Advancing the implementation of take-home naloxone by community pharmacists: Testing the role of COM-B

INTRODUCTION

Opioid-related overdose fatalities are rising despite the increased accessibility of take-home naloxone (THN). Targeted implementation strategies are needed to improve the distribution of naloxone. This study investigates the effectiveness of a short video targeting pharmacists that addresses implementation barriers.

METHODS

A pre-post, mixed methods design was adopted to examine the effect of a brief behaviour change intervention (an educational video informed by the capability, opportunity, motivation affecting behaviour (COM-B) model), on factors affecting pharmacists' implementation of THN in Western Australia. Paired samples t-tests for were used to investigate intentions, knowledge, skill, confidence, feasibility, appropriateness, acceptability, attitudes, anticipated patient reactions, social support and implementation climate. Structural equation modelling examined the associations between constructs and to test the proposed mediation of motivation on capability and opportunity affecting intentions to discuss and provide THN.

RESULTS

We analysed data from 102 participants. At follow-up and after all participants had viewed the video, participants had significantly improved intentions, skill, confidence, anticipated reactions, social support and perceptions that THN implementation was feasible, appropriate and acceptable. No significant differences were seen for attitudes, knowledge or implementation climate. The proposed mediation effect of motivation on the associations between opportunity and intentions and capability and intentions was not supported.

DISCUSSION AND CONCLUSIONS

A short video directly targeting identified implementation barriers has the ability to improve key influences in the provision of THN. Dissemination of information to community pharmacists is a challenge. Implementation strategies addressing knowledge and targeting other levels of influence on intentions and behaviour are required.

Predicting the employment of teledentistry in clinical practice by the Saudi dental community using a theoretical model

Introduction

There are very few scholastic studies applying a theory-driven methodology to analyse the employment of teledentistry in clinical practice by the Saudi dental community. The objective of this research was to predict the employment of teledentistry in clinical practice by the Saudi dental community using the UTAUT (Unified Theory of Acceptance and Use of Technology) model.

Methods

A countrywide survey was executed from November 2022 to April 2023 among the dental community (pre-graduate students, graduates, post-graduate students, general dentists, and specialist dentists) involved in clinical practice. The survey employed the UTAUT model, which has four fundamental constructs: performance expectancy (PE), effort expectancy (EE), social influence (SI) and facilitating conditions (FC). These constructs are known to impact the user's behavioural intention (BI). The four fundamental constructs were independent, and BI was the dependent variable. A Likert scale with five scores was used to record each variable. Descriptive statistics were used to describe all the constructs. Cronbach's alpha scores were used to measure the inner consistency of the Likert scale. Simple linear regression and multiple linear regression were used to determine the correlation between all the constructs and the overall model's prediction. The Statistical Package for the Social Sciences was applied for analysis. The study had 80% power and an alpha threshold of .05.

Results

The electronic survey was sent to 3000 participants, out of whom 2143 responded (response rate = 71.43%). PE (R2= 26%, p < .01) was the most significant predictor of the Saudi dental community BI to employ teledentistry in clinical practice, followed by SI (R2= 24%, p < .01), EE (R2= 19%, p < .01) and FC (R2= 6%, p < .01). With statistically significant predictive power, the UTAUT model explained 32% of the variance in the BI (R2= 0.32, p < .01).

Conclusions

Each UTAUT construct and the entire model were significantly correlated with the employment of teledentistry in clinical practice by the Saudi dental community. PE had the most salient correlation, followed by SI, EE and FC. The participants have perceived the benefits of teledentistry, increasing the future likelihood of its utilisation. The Saudi government could consider the UTAUT constructs to promote teledentistry in tandem with Vision 2030.

Paediatric nurses' burnout, quality of life and perceived patient adverse events during the COVID-19 pandemic: Testing an integrated model using structural equation modelling

PURPOSE

A model was hypothesised by integrating two theoretical models: the compassion satisfaction-compassion fatigue and empowerment models. This study aimed to assess the extent to which this integrated model can explain the relationships between paediatric nurses' burnout quality of life, perceived patient safety and work-related variables during the COVID-19 pandemic.

BACKGROUND

Nurses' burnout is negatively associated with quality of life (QOL) and positively with patient safety. Several theoretical models were introduced to explain burnout determinants and outcomes such as Golembiewski, Munzenrider and Stevenson model, Leiter and Maslach's process model, and Lee and Ashforth's model. However, few models described burnout in relation to QOL or patient safety.

METHODS

A sample of 225 paediatric nurses responded to questionnaires about burnout, QOL, adverse events and work-related variables. Compassion satisfaction - compassion fatigue and empowerment models were integrated into a single model and tested using structural equation modelling analysis. This study was prepared and is reported according to the STROBE checklist.

RESULTS

The final model explained 65% of the variance of burnout and 37% of the variance of QOL. The work-related variables (co-workers' support, job satisfaction, satisfaction with the monthly salary, participation in continuous education and exposure to violence) are predicting paediatric nurses' burnout and quality of life.

CONCLUSION

The Compassion satisfaction - compassion fatigue -Empowerment integrated model allows for assessing the different paths in the relationship between work-related variables and burnout.

RELEVANCE TO CLINICAL PRACTICE

These results might be essential for nursing managers to develop strategies that improve nurses' work environment and minimise their burnout during COVID-19 pandemic. These strategies should focus on enhancing co-workers' support, job satisfaction and participation in continuous education. Furthermore, paediatric nurses should be protected from any violence.

Experimental Study on Thermal Conductivity of Water-Based Magnetic Fluid Loaded with Different Nanoparticles

Magnetic fluids, a new type of energy transfer fluid with tunable properties, have garnered significant interest from researchers worldwide. Hybrid magnetic fluids prepared by adding different types of nanoparticles exhibit superior thermophysical properties and functional characteristics. In this paper, we prepared a water-based magnetic fluid loaded with multi-walled carbon nanotubes (MCNTs), silver (Ag), and copper (Cu) to enhance thermal conductivity. Using a transient double hot-wire method, we designed and built an experimental measurement system for the thermal conductivity of magnetic fluids with an average measurement error of less than 5%. We studied the thermal conductivity of hybrid magnetic fluids under different conditions and evaluated the advantages and disadvantages of various models, including the Maxwell model, H&C model, Tim model, Y&C model, and Evans model. Our results show that MF+MCNTs, MF+Ag, and MF+Cu nanofluids can all improve the thermal conductivity of the carrier fluid, with MF+MCNTs exhibiting the best improvement effect of 10.93%. Among the five models evaluated, the Evans model had the best predictive effect with a deviation range within 5%. This work provides theoretical and practical reference for enhancing the thermal conductivity of magnetic fluids and provides a more accurate theoretical model for calculating the thermal conductivity of hybrid magnetic fluids.

Crashworthiness of Foam-Filled Cylindrical Sandwich Shells with Corrugated Cores

Inspired by material hybrid design, novel hybrid sandwich shells were developed by filling a corrugated cylindrical structure with aluminum foam to achieve higher energy absorption performance. The crushing behavior of the foam-filled corrugated sandwich cylindrical shells (FFCSCSs) was investigated using theoretical and numerical methods. Numerical results revealed a significant enhancement in the energy absorption of FFCSCSs under axial compression, showcasing a maximum specific energy absorption of 60 kJ/kg. The coupling strengthening effect is highly pronounced, with a maximum value of F¯c/F¯ reaching up to 40%. The mechanism underlying this phenomenon can be approached from two perspectives. Firstly, the intrusion of folds into the foam insertions allows for more effective foam compression, maximizing its energy absorption capacity. Secondly, foam causes the folds to bend upwards, intensifying the mutual compression between the folds. This coupling mechanism was further investigated with a focus on analyzing the influence of parameters such as the relative density of the foam, the wall thickness of the sandwich shell, and the material properties. Moreover, a theoretical model was developed to accurately predict the mean crushing force of the FFCSCSs. Based on this model, the influence of various variables on the crushing behavior of the structure was thoroughly investigated through parametric studies.

Modeling soil bacterial diversity: challenges and opportunities

Understanding the mechanisms structuring soil bacterial diversity has critical implications to advance the parametrization of species distribution models. This forum article discusses recent advances in the use of the metabolic theory of ecology applicable to soil microbiology, and highlights challenges and opportunities to inform future empirical and theoretical studies.

Accuracy of the FY-L formula in calculating intraocular lens power after small-incision lenticule extraction

Purpose

The study aimed to assess the accuracy of the FY-L formula in calculating intraocular lens (IOL) power after small-incision lenticule extraction (SMILE).

Methods

For the post-SMILE IOL calculation of the same eye, the IOL power targeting the pre-SMILE eyes' lowest myopic refractive error was used. The FY-L formula, the Emmetropia Verifying Optical Formula (EVO-L), the Barrett True-K no history, and the Shammas-L, respectively, were used to calculate the predicted refractive error of target IOL power. A comparison was made between the change in spherical equivalent induced by SMILE (SMILE-Dif) and the variance between IOL-Dif (IOL-Induced Refractive Error) before and after SMILE. The prediction error (PE) was defined as SMILE-Dif minus IOL-Dif. The proportion of eyes with PEs within ±0.25 D, ±0.50 D, ±0.75 D, and ±1.00 D, the numerical and absolute prediction errors (PEs and AEs), and the median absolute error (MedAE) were compared.

Results

In total, 80 eyes from 42 patients who underwent SMILE were included in the study. The FY-L formula generated the sample's lowest mean PE (0.06 ± 0.76 D), MAE (0.58 ± 0.50 D), and MedAE (0.47 D), respectively. The PEs in ±0.25 D, ±0.50 D, ±0.75 D, and ±1.00 D comprised 28.8%, 46.3%, 70.0%, and 87.5%, respectively, for the FY-L formula. Compared to other formulas, the FY-L formula produced the highest value with PEs for the percentage of eyes in ±0.50 D, ±0.75 D, and ±1.00 D.

Conclusion

This study demonstrates that the FY-L formula provides satisfactory outcomes in estimating the IOL power in the eyes after SMILE.

Recent Advances in THz Detection of Water

The frequency range of terahertz waves (THz waves) is between 0.1 and 10 THz and they have properties such as low energy, penetration, transients, and spectral fingerprints, which are especially sensitive to water. Terahertz, as a frontier technology, have great potential in interpreting the structure of water molecules and detecting biological water conditions, and the use of terahertz technology for water detection is currently frontier research, which is of great significance. Firstly, this paper introduces the theory of terahertz technology and summarizes the current terahertz systems used for water detection. Secondly, an overview of theoretical approaches, such as the relaxation model and effective medium theory related to water detection, the relationship between water molecular networks and terahertz spectra, and the research progress of the terahertz detection of water content and water distribution visualization, are elaborated. Finally, the challenge and outlook of applications related to the terahertz wave detection of water are discussed. The purpose of this paper is to explore the research domains on water and its related applications using terahertz technology, as well as provide a reference for innovative applications of terahertz technology in moisture detection.

A Novel Thermal Tactile Sensor Based on Micro Thermoelectric Generator for Underwater Flow Direction Perception

Underwater vehicles can operate independently in the exploitation of marine resources. However, water flow disturbance is one of the challenges underwater vehicles must face. The underwater flow direction sensing method is a feasible way to overcome the challenges but faces difficulties such as integrating the existing sensors with underwater vehicles and high-cost maintenance fees. In this research, an underwater flow direction sensing method based on the thermal tactility of the micro thermoelectric generator (MTEG) is proposed, with the theoretical model established. To verify the model, a flow direction sensing prototype is fabricated to carry out experiments under three typical working conditions. The three typical flow direction conditions are: condition No. 1, in which the flow direction is parallel to the x-axis; condition No. 2, in which the flow direction is at an angle of 45° to the x-axis; and condition No. 3, which is a variable flow direction condition based on condition No. 1 and condition No. 2. According to the experimental data, the variations and orders of the prototype output voltages under three conditions fit the theoretical model, which means the prototype can identify the flow direction of three conditions. Besides, experimental data show that in the flow velocity range of 0~5 m/s and the flow direction variation range of 0~90°, the prototype can accurately identify the flow direction in 0~2 s. The first time utilizing MTEG on underwater flow direction perception, the underwater flow direction sensing method proposed in this research is cheaper and easier to be applied on the underwater vehicles than traditional underwater flow direction sensing methods, which means it has great application prospects in underwater vehicles. Besides, the MTEG can utilize the waste heat of the underwater vehicle battery as the energy source to achieve self-powered work, which greatly enhances its practical value.

Thermoreversible Tissue Adhesion with Hydrogel Through a Topological Entanglement Approach

Achieving thermoreversible adhesion between hydrogel and living tissues in a facile way is challenging. Existing strategies bring difficulty to the chemical design and synthesis of hydrogels. Herein, an approach to achieve tough thermoreversible tissue adhesion with hydrogel is proposed, which uses a polymer solution with heat-induced sol-gel transition as the interfacial polymer matrix, with no chemical design required for the hydrogel network. When the interfacial polymer matrix is introduced to the interface of the hydrogel and living tissues, it can gelate in situ within the substrate networks under a temperature stimulus, and topologically entangle with the preexisting networks of the substrates, which generates a strong adhesion. By triggering with another temperature stimulus, the newly formed network dissociates, to realize an easy detachment. Thermoreversible adhesion is demonstrated between polyacrylamide hydrogel and various porcine tissues as examples, and the mechanism of this adhesion strategy is studied by varying various influence factors. A theoretical model that can fit and predict the effects of different parameters on the adhesion energies is also established. This adhesion strategy based on topological entanglement among a thermoreversible polymer system and the substrates may broaden the achieving methods of thermoreversible tissue adhesion. This article is protected by copyright. All rights reserved.

Analysis of Mechanical Properties and Fatigue Life of Microturbine Angular Contact Ball Bearings under Eccentric Load Conditions

Angular contact ball bearings are common basic components in rotating machinery. During the operation of the bearing, the rolling slips, resulting in contact sliding friction between it and the raceway, which in turn causes wear in the rolling element and increase in the radial clearance of the bearing. The increase in clearance also affects the stiffness of the bearing, which in turn affects the natural frequency and fatigue life of the bearing. At present, there are few studies on the influence of bearing wear (variation of clearance) on life. In this paper, the finite element model based on the theory of contact mechanics is established for the angular contact ball bearing with medium- and high-speed rotation, and the mechanical properties and fatigue life influenced by the internal action of the bearing are analyzed. The effects of radial load and deflection angle on the mechanical properties and fatigue life of the bearing are also studied. Based on the analysis results of bearing contact mechanical properties and clearance changes, the calculation method of bearing life under rolling element wear is established. The influence of the variation of clearance and preload clearance on bearing life is analyzed, and the optimal preload is obtained. The research results of this paper can provide a theoretical basis for optimizing the installation of angular contact ball bearings, reasonably determining the service conditions, and prolonging the service life of bearings, which is necessary for engineering practice.

An examination and proposed theoretical model of risk and protective factors for bereavement outcomes for family members of individuals who engaged in medical aid in dying: A systematic review

BACKGROUND

Medical Aid in Dying is an end-of-life option that allows a physician to provide a patient with a prescription to end their life. Though Medical Aid in Dying intends to reduce suffering for a patient, opponents argue Medical Aid in Dying may increase suffering for the family members during bereavement. To better understand the bereavement outcomes for family members/friends following Medical Aid in Dying, an exhaustive review of the risk and protective factors for bereavement outcomes is warranted.

AIM

This systemic review aimed to identify studies that examined bereavement outcomes of family members of individuals who engage in Medial Aid in Dying, identify risk and protective factors for bereavement outcomes, and propose a theoretical model to enhance conceptual clarity.

DESIGN

A mixed-method systematic review.

DATA SOURCES

Ten databases were searched on June 16, 2021 and later conducted two updates (latest April 25, 2022).

RESULTS

Thirteen articles met inclusion criteria. Risk and protective factors were identified pre-Medical Aid in Dying and risk factors post-Medical Aid in Dying. Few studies compared bereavement outcomes for family members of individuals utilizing Medical Aid in Dying to family members who lost someone to natural loss.

CONCLUSIONS

This study provides equivocal results about the effects of Medical Aid in Dying on family members following the loss. The theoretical model outlines potential risk and protective factors. This model provides a greater understanding of possible universal risk and protective factors for family members of individuals who engaged in Medical Aid in Dying.

Coupled Effect of Chloride Corrosion and Repeated Uniaxial Compressive Loading on Unsaturated Concrete

Concrete structure performance continuously deteriorates during operation, and the performance is simultaneously affected by chloride corrosion and repeated traffic loading. Repeated-loading-induced cracks have an impact on the rate of chloride corrosion. Chloride-induced concrete corrosion also affect the stress level of the structure under loading. Therefore, the coupled effect of repeated loading and chloride corrosion on the structural performance needs to be investigated. An upgraded test device was developed for chloride corrosion testing of unsaturated concrete structures under repeated loading. Based on the experimental results, considering the influence of repeated loading on the moisture diffusion coefficient and the chloride diffusion coefficient, a chloride transport model for unsaturated concrete under the coupled effect of repeated uniaxial compressive loading and corrosion was established. The chloride concentration under coupled loading was determined by the Crank-Nicolson finite difference method and the Thomas algorithm, and then chloride transport under the coupled effect of repeated loading and corrosion was analyzed. The results showed that the stress level and the repeated loading cycles directly affect the relative volumetric water content and chloride concentration in unsaturated concrete. The effect of chloride corrosion is more severe in unsaturated concrete compared to saturated concrete.

Reinforcement Corrosion in RC Hollow Piers: Destructive and Non-Destructive Tests

In this work, cyclic-load tests on reduced-scale corroded reinforced-concrete hollow cross-section bridge piers have been experimentally performed and compared to the results of similar non-corroded piers. Piers were aged by using an imposed electric current and sodium chloride water solution before performing a mechanical cyclic-load test. The corrosion process has been detected with Non-Destructive Evaluation techniques by means of SonReb method (to check concrete degradation) and by measuring corrosion potential (to check steel degradation). The crack pattern was recorded by dedicated cameras, and an LVDT system was set up to monitor the cyclic-load test. Experimental results focused on degradation monitoring and mechanical performance under cyclic loads. During the cyclic-load mechanical test, the first cracks on the piers surface occurred diagonally, inclined at about 45°. This is the consequence of the failure mode change from ductile failure, as expected for slender designed piers, to brittle shear failure. The flexural failure occurred in the case of non-corroded piers. Presented tests can provide a useful contribution of experimental data to analyse the behaviour of corroded reinforced concrete hollow bridge piers, scarcely tested. In particular, the cyclic response can be a useful reference for the proposition/validation of nonlinear capacity models for the evaluation of the seismic capacity of corroded bridge piers.

Effects of condyle on disc status of the reducing and nonreducing anterior disc displacement of the temporomandibular joint based on 3D reconstructive imaging: a pilot study

OBJECTIVES

Morphologic study is a common approach in the field of anterior disc displacement (ADD) pathology; however, analysis based on 3D reconstructive imaging has not been investigated. This study investigated the association between ADD and the status of the mandibular condyle and articular fossa.

METHOD AND MATERIALS

Thirty-four patients were divided into a normal articular disc position (NADP) group, an ADD with reduction (ADDwR) group, and an ADD without reduction (ADDwoR) group. Images reconstructed were used to determine multiple grouped comparisons of these three different types of disc position, and the diagnostic efficacy for the morphologic parameters with significant grouped difference was analyzed to assess.

RESULTS

The condylar volume and condylar superficial area of the NADP, ADDwR, and ADDwoR groups exhibited obvious changes (P < .05). A multivariate logistic ordinal regression model showed that the condylar volume (odds ratio [OR], 1.011; regression coefficient [RC] = .011, P = .018), superior joint space (OR, 8.817; RC = 2.177; P < .001), and medial joint space (OR, 1.492; RC = 0.400; P = .047) had a significantly positive impact on the groups.

CONCLUSION

The mandibular condyle and articular fossa in temporomandibular joint ADD exhibited altered dimensions. The condylar volume, condylar superficial area, superior joint space, and medial joint space could be considered as promising biometric markers for assessing ADD, and were investigated in this current pilot study. (Quintessence Int 2023;54:156-166; doi: 10.3290/j.qi.b3512027).

Destructive Effect of High-Temperature Heat Flow of Solid Slow-Release Energetic Materials on a Steel Target

To investigate the high-temperature heat flow's destructive effect of solid slow-release energetic materials on a steel target, we prepared a sample of solid slow-release energetic materials, eruption devices, and a complete test system to conduct the destruction of high-temperature heat flow on the steel target. In addition, we proposed the energy density to characterise the high-temperature heat flow performance and numerically simulated the destructive effect of the high-temperature heat flow on the steel target. The numerical simulation results were in good agreement with the test results, and the error between them was under 8.5%. Based on the test and simulation results, the steady-state melting model of the steel target was established under the action of high-temperature heat flow. Moreover, a time-varying model of the melting hole shape was found. The results showed that the model of destroying the steel target with the high-temperature heat flow of solid slow-release energetic materials was highly accurate. Therefore, the model could provide theoretical guidance for designing and applying solid slow-release energetic materials in ammunition destruction, metal cutting, the simulation of the laser thermal effect, etc.

Procrastination in University Students: A Proposal of a Theoretical Model

Procrastination is a phenomenon that affects university students and consists of not finishing a task or finishing it late, which has a direct impact on their academic performance. This is relevant because, in a context of high competition, higher education institutions and their decision-makers need to be aware of the factors that influence university students' procrastination in order to implement actions that favor student attraction and retention. Based on the above, this research aims to propose a theoretical model of procrastination in university students, based on the literature review and content validation assessment through a semi-structured questionnaire. The proposed model is made up of nine dimensions: Psychological, Physiological, Social, Academic, Leisure, Time Management, Resources, Labor, and Environmental. Dimensions were obtained based on adequate levels of content validity provided by the literature and the questionnaire. In the future, the research proposes to study the way in which these dimensions are present in procrastination and design a scale that allows for their measurement.

The Complexity of Nutritional Problems in Persons with Dementia: Expanding a Theoretical Model

BACKGROUND

Persons with dementia are at risk of developing nutritional problems. Theoretical models on nutritional problems have been developed, but have not been evaluated with healthcare professionals.

OBJECTIVE

This study aimed to explore the comprehensiveness and applicability of a theoretical model of nutritional problems in persons with dementia for daily nursing home practice.

METHODS

A qualitative design employing a combined deductive and inductive approach was used. Healthcare professionals were eligible to participate if they 1) had expert knowledge of and experience with nutritional problems related to dementia, and 2) worked in a nursing home affiliated with an academic network covering the east and south of the Netherlands. Three focus group interviews with 20 healthcare professionals from seven professions were held. We conducted thematic analysis and we compared themes with existing theoretical models from the literature.

RESULTS

We identified six themes, four of which corresponded with the existing models (observing and analysing nutritional problems; consequences of nutritional problems; functioning of the person with dementia; environmental factors). Interprofessional collaboration and ethical factors were identified as new themes. The analyses indicated interactions within each theme, between themes, and a bidirectional connection between themes.

CONCLUSIONS

This study demonstrated the relevance of interprofessional collaboration and ethical considerations in nutritional problems related to dementia. It uncovered complex bidirectional relations within and between factors regarding nutritional problems. All aspects should be taken into account to minimize the consequences of nutritional problems for persons with dementia.

Theoretical and experimental studies on the oil-based emulsion spray

Oil-based emulsion is a common herbicide formulation in agricultural spray, and its atomization mechanism is different from that of water spray. In this paper, a theoretical model based on the characteristics of spray sheets was proposed to predict the spray droplet size for oil-based emulsion spray. An image processing method was used to measure droplet size distributions for different spray pressures and nozzle configurations, and the measured results were used to validate the theoretical model. The results show that oil-based emulsion spray is characterized by the web structure constituted by perforations. The liquid originally occupied by spray sheets eventually gathers in these web structures. The proposed theoretical model is based on the size of the nozzle exit, the angle of spray sheets, and the perforation number in the web structure, which are relatively easy to obtain. The theoretical droplet size is in inverse proportion to the square root of the perforation number in the web structure while in proportion to the square root of the area of the nozzle exit. The captured images of spray sheets and the measured droplet size distribution show consistency with the theoretical prediction. The difference between theoretical results and measured volumetric median diameter is less than 10% for different spray pressures and nozzles.

Nutrition in People with Dementia: What We Know and What We Need to Know to Upskill Those Who Care

Feeding and swallowing difficulties and their consequences on the nutritional status of people with dementia have been the subject of recurrent research, albeit strong evidence is still lacking. When a person no longer swallows safely, it is the caregivers who face difficulties of providing adequate care. Therefore, it is important to understand and analyze their perspectives on the topic. Despite the recent development of theoretical models to manage mealtimes and nutrition intake, the participation of health professionals and caregivers in these types of studies are still limited. The study of van Buuren et al., which this commentary refers to, aimed to identify key factors that contribute to the development of a conceptual model to step up nutritional care in dementia.

Acquired von Willebrand syndrome in patients with monoclonal gammopathy of undetermined significance investigated using a mechanistic approach

BACKGROUND

Acquired von Willebrand syndrome (AVWS) has been reported to occur in association with monoclonal gammopathy, usually of undetermined significance (MGUS). It may present as a type 1 or type 2 von Willebrand factor (VWF) defect depending on the patient's representation of large VWF multimers.

MATERIALS AND METHODS

The mathematical model by Galvanin et al., already employed for studying inherited von Willebrand disease (VWD), was used to explore the pathogenic mechanisms behind MGUS-associated AVWS.

RESULTS

The patients studied showed significantly reduced VWF levels and function; an increased VWF propeptide to VWF antigen ratio; and all VWF multimers present but in reduced quantities, with the low-molecular-weight VWF forms being significantly more represented than those of higher molecular weight. Our mathematical model revealed a significantly increased VWF elimination rate constant, with values similar to those of type Vicenza VWD. An even more increased VWF proteolysis rate constant was observed, with values one order of magnitude higher than in type 2A VWD but, in contrast, no loss of large multimers. The model predicted the same elimination rate for high- and low-molecular-weight VWF multimers, but proteolysis of the high-molecular-weight forms also contributes to the pool of low-molecular-weight oligomers, which explains why they were relatively over-represented.

DISCUSSION

In MGUS-associated AVWS the increase of both clearance and proteolysis contributes to the circulating levels and multimer pattern of VWF, with a phenotype that appears to be a combination of type Vicenza and type 2A VWD. Hence, the mechanisms behind the onset of AVWS seem to differ from those of inherited VWD.

Understanding the experiences and needs in autism education: A semi-structured interview among Chinese American parents of autistic children

Background and Aims

The diversity of the autistic population seeking professional services and education in the United States has increased. As the diagnosis of autism increases among the Chinese American immigrant population, there is also an increasing need to learn about this population and provide appropriate intervention and education for this group. However, current education and intervention provided for autistic individuals tend to be culturally blind. Gaps were found in our understanding of the cultural context and its relationship with the education mechanisms among Chinese American autistic families. The current study intends to investigate how Chinese American parents perceive the education materials and intervention strategies received by their autistic children as well as their experiences and needs in the education process.

Method

Semi-structured interviews were conducted among 10 Chinese American parents (one father and nine mothers) online. They all had children who had a formal diagnosis of autism spectrum disorder and received some intervention or education. Thematic analysis was used to analyse the results.

Results

The study suggested that most Chinese American parents were satisfied with the current education materials and intervention strategies provided to their autistic children. Due to cultural-related stigma, parents differ in their perceptions of children's autism diagnosis and characteristics as well as their expectations of children's culturally sensitive education. A theoretical model was created to provide culture-centered interpretation of the interconnected relationship between their pre- and post-immigration contexts and parenting attitudes.

Conclusions

Culture plays a critical role in understanding Chinese American parents' experiences, needs, and expectations of culturally sensitive education for their autistic children. Interconnected relationships were found between contexts and parenting attitudes, which were largely influenced by cultural-related stigma.

Implications

Suggestions and implications were provided for institutions and professionals working with Chinese American families and children. It is critical for them to learn about the experiences, needs, and attitudes of Chinese American parents to provide Chinese American autistic children with more appropriate and culturally sensitive education.

A Shear-Mode Magnetoelectric Heterostructure with Enhanced Magnetoelectric Response for Stray Power-Frequency Magnetic Field Energy Harvesting

This paper devises a magnetoelectric (ME) heterostructure to harvest ambient stray power-frequency (50 Hz or 60 Hz) magnetic field energy. The device explores the shear piezoelectric effect of the PZT-5A plates and the magnetostrictive activity of the Terfenol-D plates. The utilization of the high-permeability films helps to enhance the magnetoelectric response to the applied alternating magnetic field. A theoretical model is developed based on the piezomagnetic and piezoelectric constitutive equations as well as the boundary conditions. The ME response of the device is characterized theoretically and experimentally. The measured ME voltage coefficient attains 165.2 mV/Oe at the frequency of 50 Hz, which shows a good agreement with the theoretical result. The feasibility for extracting energy from the 50 Hz magnetic field is validated. Under an external alternating magnetic field of 30 Oe, a maximum power of 8.69 μW is generated across an optimal load resistance of 693 kΩ. Improvements of the ME heterostructure are practicable, which allows an enhancement of the ME voltage coefficient and the maximum power by optimizing the structural parameters and utilizing PMN-PT with a higher shear-mode piezoelectric voltage coefficient (g₁₅).

Stress-Induced Microcracking and Fracture Characterization for Ultra-High-Temperature Ceramic Matrix Composites at High Temperatures

In this paper, we estimated the temperature-dependent critical inclusion size for microcracking under residual stress and applied stress for particulate-reinforced ultra-high-temperature ceramic matrix composites. The critical flaw size and applied stress for the stable growth of radial cracks under different temperatures were also estimated. It was found that under a lower applied stress, the critical inclusion size was sensitive to the temperature. Under higher applied stresses, the sensitivity became smaller. For ceramic materials with pre-existing microcracks, the crack resistance could be improved by increasing the service stress when the service stress was low. As the temperature increased, the critical flaw size of the materials decreased; the applied stress first increased and then decreased. Finally, a temperature-dependent fracture strength model of composites with a pre-existing critical flaw was proposed. A good agreement was obtained between the model prediction and the experimental data. In this work, we show a method for the characterization of the effects of temperature on the fracture behavior of ceramic-based composites.

Theoretical Modeling Method for Material Removal Characteristics of Abrasive Water Jet Polishing under Rotating Oblique Incidence

Abrasive water jet polishing (AWJP), as an ultra-precision machining technology, has unique machining advantages. However, the machining application of nozzles in vertical and inclined states is greatly limited because rotational symmetric material removal characteristics and the largest amount of central material removal cannot be obtained. At the same time, considering the many controllable and uncontrollable factors in AWJP, it is difficult to accurately model the removal characteristics obtained by machining. Based on the idea of the Preston equation and the calculation of fluid dynamics, this study first analyzed the material removal characteristics of a single abrasive particle and used FLUENT fluid simulation software to obtain the pressure and velocity distributions at different positions in the processes of nozzle rotation and tilt polishing. By analyzing the influence of the pressure and velocity distributions on material removal and the surface shear stress of the workpiece, a theoretical model of the material removal characteristics of abrasive water jet polishing under rotating oblique incidence was established. Finally, the effectiveness of the theoretical removal model was verified by comparing and analyzing experimental and theoretical results.

Thermally driven single-electron stochastic resonance

Stochastic resonance (SR) in a single-electron system is expected to allow information to be correctly carried and processed by single electrons in the presence of thermal fluctuations. Here, we comprehensively study thermally driven single-electron SR. The response of the system to a weak voltage signal is formulated by considering the single-electron tunneling rate, instead of the Kramers' rate generally used in conventional SR models. The model indicates that the response of the system is maximized at finite temperature and that the peak position is determined by the charging energy. This model quantitatively reproduces the results of a single-electron device simulator. Single-electron SR is also demonstrated using a GaAs-based single-electron system that integrates a quantum dot and a high-sensitivity charge detector. The developed model will contribute to our understanding of single-electron SR and will facilitate accurate prediction, design, and control of single-electron systems.

Relationships Among Environmental Variables, Physical Capacity, Balance Self-Efficacy, and Real-World Walking Activity Post-Stroke

BACKGROUND

Social and physical environmental factors affect real-world walking activity in individuals with stroke. However, environmental factors are often non-modifiable, presenting a challenge for clinicians working with individuals with stroke whose real-world walking is limited due to environmental barriers.

OBJECTIVE

The purpose of this work was to test a model hypothesizing the relationships among environmental factors (specifically, living situation and area deprivation), modifiable factors, and real-world walking activity to understand opportunities for intervention. We hypothesized that balance self-efficacy would mediate the relationship between the environment and real-world walking and that physical capacity would moderate this mediation.

METHODS

This was a cross-sectional study of 282 individuals with chronic (≥6 months) stroke. We tested the indirect effect to determine if mediation was present. Multiple group structural equation modeling was used to test if physical capacity moderated this mediation. A χ² difference test was used to compare the moderation model against the null (no moderation) model.

RESULTS

Balance self-efficacy mediated the relationship between area deprivation and real-world walking (indirect effect: β = -0.04, P = .04). Both the moderation and null models fit the data equally well statistically (χ²(5) = 6.9, P = .23). We therefore accepted the simpler (null) model and concluded that the mediation was not moderated.

CONCLUSIONS

Targeting balance self-efficacy may be an effective approach to improving real-world walking in persons with stroke who experience barriers within the physical environment. A stroke survivor's physical capacity may not impact this approach. Future work should consider utilizing more specific measures of the social and physical environment to better understand their influences on real-world walking activity in individuals with stroke. However, the results of this work provide excellent targets for future longitudinal studies targeting real-world walking activity in stroke.

Monitoring COVID-19 in Colombia during the first year of the pandemic

Background:

COVID-19 cases in Medellín, the second largest city in Colombia, were monitored during the first year of the pandemic using both mathematical models based on transmission theory and surveillance from each observed epidemic phase.

Design and Methods:

Expected cases were estimated using mandatory reporting data from Colombia’s national epidemiological surveillance system from March 7, 2020 to March 7, 2021. Initially, the range of daily expected cases was estimated using a Borel-Tanner stochastic model and a deterministic Susceptible-Infected-Removed (SIR) model. A subsequent expanded version of the SIR model was used to include asymptomatic cases, severe cases and deaths. The moving average, standard deviation, and goodness of fit of estimated cases relative to confirmed reported cases were assessed, and local transmission in Medellin was contrasted with national transmission in Colombia.

Results:

The initial phase was characterized by imported case detection and the later phase by community transmission and increases in case magnitude and severity. In the initial phase, a maximum range of expected cases was obtained based on the stochastic model, which even accounted for the reduction of new imported cases following the closure of international airports. The deterministic estimate achieved an adequate fit with respect to accumulated cases until the conclusion of the mandatory national quarantine and gradual reopening, when reported cases increased. The estimated new cases were reasonably fit with the maximum reported incidence.

Conclusion:

Adequate model fit was obtained with the reported data. This experience of monitoring epidemic trajectory can be extended using models adapted to local conditions.

Patient and public involvement in oesophageal cancer survivorship research

BACKGROUND

Good clinical research is often conducted in close collaboration between patients, the public, and researchers. Few studies have reported the development of patient and public involvement (PPI) in research outside the United States and the United Kingdom, and for patients with more aggressive cancers. The study aimed to describe and evaluate the development of PPI in oesophageal cancer survivorship research in Sweden by the use of a framework to support the process.

METHODS

Oesophageal cancer survivors were recruited to a PPI research collaboration at Karolinska Institutet, Sweden. The development process was supported by the use of a framework for PPI, 'Patient and service user engagement in research'. Insights, benefits, and challenges of the process were described and discussed among the collaborators.

RESULTS

The collaboration resulted in joint publications with a more patient- and family-focussed perspective. It also contributed to the development of information folders about survivorship after oesophageal cancer surgery and national conference arrangements for patients, their families, healthcare workers, and researchers. Since the PPI contributors were represented in patient organisations and care programmes, the dissemination of research results increased. Their contributions were highly valued by the researchers, but also revealed some challenges. The use of a structured framework contributed to support and facilitated the process of establishing PPI in research collaboration.

CONCLUSIONS

A genuine interest in establishing PPI in research and an understanding and respect for the patients' expertise in providing a unique inside perspective was imperative for a successful collaboration. Research focus should not only be on mortality and reductions in daily life, but also on positive outcomes. Using a framework supports development and avoids pitfalls of PPI collaboration.

PATIENT AND PUBLIC CONTRIBUTION

Patient partners were equal collaborators in all aspects of the study.

Enhancement of Aging in Place: An Evolving Understanding of Person-Centered Dementia Care in Home Settings

BACKGROUND

There has been a rich body of literature on informal caregivers of persons with dementia (PWD). However, little has been discussed on how to facilitate person-centered dementia care in home settings with spouses as primary caregivers. We tend to take it for granted that spouses provide person-centered care for PWD. However, being spouses of PWD and living with them for several decades does not necessarily mean that it is easier for them to provide person-centered dementia care and maintain valued and healthy relationships.

OBJECTIVE

The current study aimed to explore dyadic experiences of PWD and their spousal caregivers and develop a culturally and contextually-sensitive understanding of person-centered dementia care in home-based settings.

METHODS

A total of 20 dyads of PWD and their care partners were selected for this study. A trained qualitative interviewer conducted a one-on-one interview with each participant with dementia and their care partners separately. We adopted both conventional and directed content analyses.

RESULTS

Our findings provide examples of care partners provide person-centered care, resulting in a profound positive impact on their wellbeing. Adaptive leadership and collaborative work emerged as a key finding in facilitating person-centered dementia care. Cultural relevancy of person-centered dementia care was also interpreted from the data. The study findings provide implications for the evolving of person-centered dementia care model in home-based settings.

CONCLUSION

Findings from this study highlight the significance of facilitating person-centered dementia care in home-based settings between PWD and their primary family caregivers.

The relationship between the manifestations of mobbing and reactions of mobbing victims

BACKGROUND

The study concerned workplace mobbing, a phenomenon affecting about 3-20% of the Polish population. The aim of the article is to distinguish the manifestations of mobbing, to study the coexistence of mobbing manifestations, and to search for the relationships between the symptoms of mobbing, reactions to mobbing and methods of dealing with mobbing used by victims.

MATERIAL AND METHODS

Information on the above variables was obtained using a questionnaire on mobbing, risk factors, and responses to mobbing. The questionnaire was completed by 781 people (women: 66%, men: 34%). The average age of the respondents was 29 years. The current statistical analysis included: distinguishing the manifestations of mobbing by means of a confirmatory factor analysis, studying the coexistence of mobbing manifestations by means of a cluster analysis, and detecting the relationships between mobbing manifestations, reactions to mobbing and ways of dealing with it based on the system of structural equations.

RESULTS

The results of the research revealed 3 categories of relationships: a co-occurrence of mobbing manifestations, a relationship of mobbing manifestations with reactions to mobbing, and a relationship of mobbing reactions with methods of dealing with mobbing.

CONCLUSIONS

Mobbing was found in 22% of the examined group. The study revealed the existence of 5 clusters of mobbing manifestations (i.e., subgroups of respondents characterized by experiencing at least 1 of the mobbing manifestations). In the most numerous clusters in which the symptoms of mobbing were diagnosed, unfriendly working conditions prevailed. In the context of mobbing, people were found to more often react with passivity or with using interpersonal coping methods. However, they rarely turned to institutions for help or used aggression against the mobber. Med Pr. 2022;73(1).

Theoretical and Experimental Investigation on the 3D Surface Roughness of Material Extrusion Additive Manufacturing Products

Material extrusion (ME), one of the most widely used additive manufacturing technique, has the advantages of freedom of design, wide range of raw materials, strong ability to manufacture complex products, etc. However, ME products have obvious surface defects due to the layer-by-layer manufacturing characteristics. To reveal the generation mechanism, the three-dimensional surface roughness (3DSR) of ME products was investigated theoretically and experimentally. Based on the forming process of bonding neck, the 3DSR theoretical model in two different directions (vertical and parallel to the fiber direction) was established respectively. The preparation of ME samples was then completed and a series of experimental tests were performed to determine their surface roughness with the laser microscope. Through the comparison between theoretical and experimental results, the proposed model was validated. In addition, sensitivity analysis is implemented onto the proposed model, investigating how layer thickness, extrusion temperature, and extrusion width influence the samples' surface roughness. This study provides theoretical basis and technical insight into improving the surface quality of ME products.

Theoretical model and measurement of shared decision making in web-based pharmaceutical care consultation

Objectives

We aimed to construct a theoretical model and an observer-based measurement of shared decision making (SDM) in web-based pharmaceutical care consultation.

Methods

We first constructed a theoretical model through analysis of SDM models and interviews with 24 key informants. Then, the initial measurement was formulated, and the content was evaluated by 16 key informants alone. A cross-sectional study was executed, where 300 provider-patient encounters were collected at the online platform ‘Good Doctor Website’, for reliability and validity assessment. Content validity was evaluated by appropriateness score, that is the median of 7–9 and without disagreement. Interrater reliability was evaluated by Spearman correlation coefficient using 30 out of 300 samples. Single indicator validity was tested by Pearson correlation analysis, and convergent validity was evaluated by the Multiple Indicators Multiple Causes (MIMIC) model using 300 samples.

Results

Theoretical model constructed included four elements: ‘comprehensive understanding of the patient's condition’, ‘exchanging ideas on medication options’, ‘achieving a medication plan’, and ‘providing decision support’. Measurement constructed included four dimensions and 19 items, and four dimensions were in accordance with four elements of the theoretical model. We found median scores of these dimensions and items were 7–9 and without disagreement, indicating good content validity. Spearman correlation coefficients of 19 items were greater than 0.750, suggesting good interrater reliability. Pearson coefficients between 19 items and their external variables were significant (p < 0.001), and MIMIC model results showed that the R² values of dimensions 1–4 were over 0.5, indicating good single indicator validity and convergent validity.

Conclusions

Characteristics of web-based pharmaceutical care consultation, highlighting the importance of medication history, medication regimen, and detailed medication plan, were observed in the theoretical model. Measurement constructed had good reliability and validity and may be used by health policymakers to improve the quality of pharmaceutical care consultation online.

Development and Proof-of-Concept Evaluation of a Sensory Science-Based Model for Product Development of Vegetable-Based Products for Children

Children's vegetable intake is too low, and a key barrier to the inadequate intake is low acceptance. To facilitate successful development of new vegetable-based products for children, a sensory science approach to product development has been taken. A new theoretical model is proposed, the CAMPOV model: Children's Acceptance Model for Product development of Vegetables. The model is informed by scientific literature and considers biological, psychological, and situational, and intrinsic and extrinsic product factors relevant to children's acceptance of vegetables, with a focus on modifiable factors at the product level. Simultaneously, 14 new vegetable-based product concepts for children were developed and evaluated through focus groups with 5-8-year-olds (n = 36) as a proof-of-concept evaluation of the model. Children had high interest in six of the concepts. Factors identified from the literature that positively associated with the children's interest in the concepts included bright colours, bite-sized pieces, good taste, fun eating experience, and familiarity. The CAMPOV model and proof-of-concept evaluation results can guide further sensory and consumer research to increase children's acceptance of food products containing vegetables, which will in turn provide further insights into the validity of the model. The food industry can use the model as a framework for development of new products for children with high sensory appeal.

Study on Mechanical Characteristics of Segmental Joints of a Large-Diameter Shield Tunnel under Ultrahigh Water Pressure

At present, there is no clear design standard for segmental joints of large-diameter shield tunnels under high water pressure. In this paper, a theoretical calculation model for the bending stiffness of segmental joints under high water pressure is proposed. The numerical simulation method is used to investigate the failure and crack formation processes of single-layer and double-layer lining segments under large axial forces. The effects of axial force, bolt strength, and concrete strength on the bending stiffness of joints are then studied using a theoretical calculation model of segmental joints. The results show that under extremely high water pressure, the influence of double lining on joint stiffness is limited. It is more rational and safe to compute the bending stiffness of segmental joints using this theoretical model rather than the numerical simulation method. The parameter analysis reveals that increasing the bolt strength has a minor impact on bending stiffness and deformation, whereas increasing the concrete strength has the opposite effect. The influence of ultimate bearing capacity and deformation decreases non-linearly as the axial force increases.

Determinants of Intention to Use Artificial Intelligence-Based Diagnosis Support System Among Prospective Physicians

Background: This study aimed to develop a theoretical model to explore the behavioral intentions of medical students to adopt an AI-based Diagnosis Support System.

Methods: This online cross-sectional survey used the unified theory of user acceptance of technology (UTAUT) to examine the intentions to use an AI-based Diagnosis Support System in 211 undergraduate medical students in Vietnam. Partial least squares (PLS) structural equational modeling was employed to assess the relationship between latent constructs.

Results: Effort expectancy (β = 0.201, p < 0.05) and social influence (β = 0.574, p < 0.05) were positively associated with initial trust, while no association was found between performance expectancy and initial trust (p > 0.05). Only social influence (β = 0.527, p < 0.05) was positively related to the behavioral intention.

Conclusions: This study highlights positive behavioral intentions in using an AI-based diagnosis support system among prospective Vietnamese physicians, as well as the effect of social influence on this choice. The development of AI-based competent curricula should be considered when reforming medical education in Vietnam.

Olfactory landmarks and path integration converge to form a cognitive spatial map

The convergence of internal path integration and external sensory landmarks generates a cognitive spatial map in the hippocampus. We studied how localized odor cues are recognized as landmarks by recording the activity of neurons in CA1 during a virtual navigation task. We found that odor cues enriched place cell representations, dramatically improving navigation. Presentation of the same odor at different locations generated distinct place cell representations. An odor cue at a proximal location enhanced the local place cell density and also led to the formation of place cells beyond the cue. This resulted in the recognition of a second, more distal odor cue as a distinct landmark, suggesting an iterative mechanism for extending spatial representations into unknown territory. Our results establish that odors can serve as landmarks, motivating a model in which path integration and odor landmarks interact sequentially and iteratively to generate cognitive spatial maps over long distances.

Model of Social Support for Patients Treated for Cancer

Social support can be one of the main factors in better assessing the quality of life at any stage of the recovery process. It should meet the patient's needs so that they can develop constructive methods of coping with the disease. In order to explain the factors influencing social support for cancer patients, a theoretical research model was formulated. It is presented in a graphic form in this article. In order to verify the model, the authors' questionnaire and other standardised questionnaires were used. The experimental group consisted of 170 hospitalised oncological patients being treated for cancer. Personality structure, through its relationship with state of health (0.40) and attitude developed to the disease (0.64), influenced the support experienced by the treated patients (0.40). The surveyed patients, who were characterised by positive self-esteem and experience of life satisfaction despite various difficult situations, perceived to a greater degree the emotional and instrumental support provided to them. During cancer treatment, those patients who showed a need for help and did not experience negative emotions were characterised by an increased need for support. The research results can be introduced into evidence-based medical practice, which could significantly improve the quality of nursing and medical care for patients.

Government Epidemic Prevention and Economic Growth Path Under Public Health Emergency: Theoretical Model and Simulation Analysis

This paper constructs a partial equilibrium model under public health emergency shocks based on economic growth theory, and investigates the relationship between government intervention and virus transmission and economic growth path. We found that both close contacts tracing measures and isolation measures are beneficial to human capital stock and economic output per capita, and the effect of close contact tracing measures is better than that of isolation measures. For infectious diseases of different intensities, economic growth pathways differed across interventions. For low contagious public health emergencies, the focus should be on the coordination of isolation and tracing measures. For highly contagious public health emergencies, strict isolation, and tracing measures have limited effect in repairing the negative economic impact of the outbreak. The theoretical model provides a basic paradigm for the future researches to study economic growth under health emergencies, with good scalability and robustness.

[Behavioral imaging of serum albumin during matrine transport based on capillary electrophoresis]

Matrine (MT) is an alkaloid widely used in the treatment of tumor diseases. It is the main medicinal ingredient in the dried roots of kuh-seng (Sophora flavescens Ait). However, there have been few studies on its transport mechanism. Serum albumin (SA) is the most abundant protein in blood. SA combines easily with many substances, including MT. MT and human serum albumin (HSA) were analyzed by capillary electrophoresis (CE) under in vitro conditions. The capillary tubing was 50 μm. The total length of the capillary was 60 cm, the total effective length was 50 cm. The interaction models of ligand-receptor binding were constructed by the mobility and frontal analysis (FA) methods. The purpose of establishing the interaction model was to study the binding of MT and SA. The phosphate buffer solution (PBS, 0.02 mol/L) was prepared in double distilled water. All solutions were prepared in PBS (0.02 mol/L). All solutions were filtered twice through a 0.45 μm microporous membrane, degassed for 5 min at a time. In the mobility method, different gradient MT solutions were used as running buffers. Their concentrations were 1.0×10^-4-1.0×10^-3 mol/L, with the gradient of 1.0×10^-4 mol/L. And the HSA solution containing (0.5% (v/v)) acetone was used as test sample. Its concentration was 1.0×10^-5 mol/L. The nonlinear fitting method was used to obtain the binding parameters of MT and HSA. In the FA method, different gradient MT-HSA solutions were used as test samples. Their concentrations were 1.0×10^-4-1.0×10^-3 mol/L, with the gradient of 1.0×10^-4 mol/L. And the PBS solution (0.02 mol/L) was used as running buffer. Then three equations were used to obtain the binding parameters of MT and HSA. And the applicability of the models was analyzed using the binding parameters. These three equations were nonlinear regression equation, Scatchard linear equation, and Klotz linear equation. Using the mobility method, the apparent binding constant K_B was 8.072×10³ mol/L. According to the FA method, three apparent binding constants were obtained for MT and HSA. The apparent binding constant K_B of HSA and MT by nonlinear regression equation, Scatchard linear equation and Klotz linear equation were 1.434×10³, 1.781×10³ and 2.133×10³ mol/L. The comparison was as follows, K_{B(nonlinear regression equation)} < K_{B(Scatchard linear equation)} < K_{B(Klotz linear equation)}. The number of binding sites was about 1.0. It was indicating that MT had only a single type of binding site with HSA. By analyzing the applicability of the model, the correlation coefficients (r) of the three equations were obtained. The comparison was as follows, r_{(Klotz linear equations)} > r_{(nonlinear regression equations)} > r_{(Scatchard linear equations)}. The results showed that both the methods were all suitable for analyzing the MT-SA system. The FA method could calculate the apparent binding constants and the numbers of binding sites. Therefore, it was more suitable for the analysis of MT and HSA. And the Klotz linear equation was the best fit for the theoretical model among the three equations. The combined parameters indicated that the interaction of MT with HSA had only one binding site. And the binding of MT with HSA was stable. This experimental method could be used to determine the binding status of MT and HSA. It is useful to further explore the binding mechanism of MT and HSA. This work provides valuable information on the interaction mechanism of typical alkaloids with SA. It will be useful in studies of the blood transport mechanisms of alkaloids.

Health and Risk Behaviors of Bystanders: An Integrative Theoretical Model of Bystanders' Reactions to Mistreatment

This article constructs a comprehensive theoretical model that outlines bystanders' emotional and behavioral responses to the mistreatment of adolescent peers. The model captures bystanders' risk and health risk behaviors, which have been overlooked in the context of their reactions; when addressed at all in connection with bystanders of bullying among adolescents, they have been treated separately. Here, we present bystanders' emotional and cognitive reactions and their impact on bystanders' responses including a set of responses that demonstrate risk and health risk behaviors that are directed to the bystander as a victim by proxy. The theoretical framework is the conservation of resources theory, which posits that personal resources (i.e., potency and moral disengagement) and social resources impact the process that leads to bystanders' reactions. Previous models have overlooked the integrative viewpoint of bystanders, and comprehensive models that explain bystanders' behavioral and emotional responses have received little attention especially with regards to adolescents. Two recent models overlooked core features embedded in the current model, including the risk and health risk behaviors that it integrates. The proposed model presents a novel and more comprehensive view of bystanders' reactions and the process underlying these reactions. It integrates existing knowledge embedded in other existing models. At the same time, this perspective indicates the centricity of potency as a key resource that dictates the emotional response and behaviors of bystanders. This potentially allows for new applications in the mitigation of adverse impacts that follow the witnessing of mistreatment. The article discusses these applications, which are based on previous findings, their implications for practice, and directions for future empirical research necessary to validate the model.

Distinct roles of red-blood-cell-derived and wall-derived mechanisms in metabolic regulation of blood flow

OBJECTIVE

A theoretical model is used to analyze combinations of RBC-derived and wall-derived (RBC-independent) mechanisms for metabolic blood flow regulation, with regard to their oxygen transport properties.

METHODS

Heterogeneous microvascular network structures are derived from observations in rat mesentery and hamster cremaster. The effectiveness of metabolic blood flow regulation using combinations of RBC-dependent and RBC-independent mechanisms is simulated in these networks under conditions of reduced oxygen delivery and increased oxygen demand.

RESULTS

Metabolic regulation by a wall-derived mechanism results in higher predicted total blood flow rate and number of flowing vessels, and lower tissue hypoxic fraction, than regulation by combinations of RBC-derived and wall-derived signals. However, a combination of RBC-derived and wall-derived signals results in a higher predicted median tissue P_O2 than either mechanism acting alone.

CONCLUSIONS

Model results suggest complementary roles for RBC-derived and wall-derived mechanisms of metabolic flow regulation, with the wall-derived mechanism responsible for avoiding hypoxia, and the RBC-derived mechanism responsible for maintaining P_O2 levels high enough for optimal tissue function.

Is mitochondrial reactive oxygen species production proportional to oxygen consumption? A theoretical consideration

It has been assumed that at the whole organismal level, the mitochondrial reactive oxygen species (ROS) production is proportional to the oxygen consumption. Recently, a number of researchers have challenged this assumption, based on the observation that the ROS production per unit oxygen consumed in the resting state of mitochondrial respiration is much higher than that in the active state. Here, we develop a simple model to investigate the validity of the assumption and the challenge of it. The model highlights the significance of the time budget that mitochondria operate in the different respiration states. The model suggests that under three physiologically possible conditions, the difference in ROS production per unit oxygen consumed between the respiration states does not upset the proportionality between the whole animal ROS production and oxygen consumption. The model also shows that mitochondrial uncoupling generally enhances the proportionality.

Cause or Effect? The Role of Prognostic Uncertainty in the Fear of Cancer Recurrence

Background

Fear of cancer recurrence (FCR) is an important cause of suffering for cancer survivors, and both empirical evidence and theoretical models suggest that prognostic uncertainty plays a causal role in its development. However, the relationship between prognostic uncertainty and FCR is incompletely understood.

Objective

To explore the relationship between prognostic uncertainty and FCR among patients with ovarian cancer (OC).

Design

A qualitative study was conducted utilizing individual in-depth interviews with a convenience sample of patients with epithelial ovarian cancer who had completed first-line treatment with surgery and/or chemotherapy. Semi-structured interviews explored participants’ (1) understanding of their prognosis; (2) experiences, preferences, and attitudes regarding prognostic information; and (3) strategies for coping with prognostic uncertainty. Inductive qualitative analysis and line-by-line software-assisted coding of interview transcripts was conducted to identify key themes and generate theoretical insights on the relationship between prognostic uncertainty and FCR.

Results

The study sample consisted of 21 participants, nearly all of whom reported experiencing significant FCR, which they traced to an awareness of the possibility of a bad outcome. Some participants valued and pursued prognostic information as a means of coping with this awareness, suggesting that prognostic uncertainty causes FCR. However, most participants acknowledged fundamental limits to both the certainty and value of prognostic information, and engaged in various strategies aimed not at reducing but constructing and maintaining prognostic uncertainty as a means of sustaining hope in the possibility of a good outcome. Participants’ comments suggested that prognostic uncertainty, fear, and hope are connected by complex, bi-directional causal pathways mediated by processes that allow patients to cope with, construct, and maintain their uncertainty. A provisional dual-process theoretical model was developed to capture these pathways.

Conclusion

Among patients with OC, prognostic uncertainty is both a cause and an effect of FCR—a fear-inducing stimulus and a hope-sustaining response constructed and maintained through various strategies. More work is needed to elucidate the relationships between prognostic uncertainty, fear, and hope, to validate and refine our theoretical model, and to develop interventions to help patients with OC and other serious illnesses to achieve an optimal balance between these states.

Experimental Investigation and Modeling of Damage Accumulation of EN-AW 2024 Aluminum Alloy under Creep Condition at Elevated Temperature

The paper is focused on creep-rupture tests of samples made of the 2024 alloy in the T3511 temper under uniaxial tensile stress conditions. The basic characteristics of the material at the temperatures of 100, 200 and 300 °C were determined, such as the Young’s modulus E, yield point σ_y, ultimate tensile strength σ_c and parameters K and n of the Ramberg–Osgood equation. Creep tests were performed for several different levels of nominal axial stress (load) at each temperature. It was observed that in the process of creep to failure at 200 and 300 °C, as the stress decreases, the creep time increases and, at the same time, the strain at rupture increases. However, such a regularity is maintained until a certain transition stress value σ_t is reached. Reducing the stress below this value results in a decreased value of the strain at rupture. A simple model of creep damage accumulation was proposed for the stress range above the transient value. In this model, the increase in the isotropic damage state variable was made dependent on the value of axial stress and the increase in plastic axial strain. Using the results of experimental creep-rupture tests and the failure condition, the parameters of the proposed model were determined. The surface of fractures obtained in the creep tests with the use of SEM technology was also analyzed.

Fiber-Based Gas Filter Assembled via In Situ Synthesis of ZIF-8 Metal Organic Frameworks for an Optimal Adsorption of SO2: Experimental and Theoretical Approaches

For environmental protection from exposure to airborne toxic gases, metal organic frameworks (MOFs) have drawn great attention as gas adsorbent options, with their advantages in chemical tailorability and large porosity. To develop a fiber-based gas filter that is effective against SO₂ gas, zeolite imidazole framework-8 (ZIF-8) was applied to polypropylene nonwoven by various methods. Among the tested methods, the sol-gel impregnation method showed the highest ZIF-8 loading efficiency. There existed an optimal loading of ZIF-8 for the maximum adsorption efficiency, and it was associated with the accessibility of gas molecules to the ZIF-8 pores and active sites. Dominant adsorption processes and mechanisms were investigated by fitting the theoretical sorption models to experimental data. The results demonstrate that the increased ZIF-8 loading to fibers, beyond a certain level, may hinder the diffusivity and increase the barrier effect, eventually decreasing the adsorption efficiency. This study is novel and significant in that a multifaceted approach, including experimental analysis, theoretical investigation, and computational modeling, was made for scrutinizing the intricate phenomena occurring in the gas sorption process. The results of this study provide the fundamental yet practical information on the manufacturing considerations for the optimal design of MOF-loaded fibrous adsorbents.

From Topological Analyses to Functional Modeling: The Case of Hippocampus

Topological data analyses are widely used for describing and conceptualizing large volumes of neurobiological data, e.g., for quantifying spiking outputs of large neuronal ensembles and thus understanding the functions of the corresponding networks. Below we discuss an approach in which convergent topological analyses produce insights into how information may be processed in mammalian hippocampus—a brain part that plays a key role in learning and memory. The resulting functional model provides a unifying framework for integrating spiking data at different timescales and following the course of spatial learning at different levels of spatiotemporal granularity. This approach allows accounting for contributions from various physiological phenomena into spatial cognition—the neuronal spiking statistics, the effects of spiking synchronization by different brain waves, the roles played by synaptic efficacies and so forth. In particular, it is possible to demonstrate that networks with plastic and transient synaptic architectures can encode stable cognitive maps, revealing the characteristic timescales of memory processing.

An Integrated Model of Nature and Nurture Factors that Contribute to Addiction and Recovery

BACKGROUND

In the context of the opioid epidemic and growing awareness of addiction as a public health concern, there are efforts to inform the public, patients, families, and policy makers about the factors that contribute to addiction and facilitate recovery. Several theoretical models provide useful frameworks for this discussion, but each of them has limitations.

OBJECTIVES

This paper presents an accessible yet comprehensive theoretical model that integrates empirical evidence about addiction etiology and recovery using the nature-nurture paradigm.

RESULTS

The model presents substance use along a continuum, and identifies risk and protective factors in multiple domains that have been identified by research. The domains on the nature side of the model include genetic and biological factors, comorbid psychiatric and medical disorders, physiological reinforcement of substance use, and changes to neural mechanisms. The domains on the nurture side of the model include sociocultural factors, environmental factors, personality, emotions, cognitions, psychological reinforcement of substance use, and cognitive and behavioral changes. The progression from increased or decreased substance use to addiction or recovery is mediated by changes in neural mechanisms and cognitive and behavioral changes, which have feedback loops with the physiological and psychological reinforcement.Conclusions/Importance: This model is a useful heuristic, consistent with a public health framework, for discussing addiction and recovery with patients, their families, and the public. This integrated model of nature and nurture factors has the potential to inform clinical practice, consultation, research, prevention programs, educational programs, and public policy.

Theoretical analysis of the hydrodynamic filtering system in the balaenid whales suspension feeding

Balaenid whales are giant filter feeders that feed on the dense aggregations of prey. Through their unique oral filters, they can effectively filter water out and leave prey in their mouths. In this study, a theoretical model is established to analyze the hydrodynamic filtering system in the balaenid whales suspension feeding. First, the appropriate velocity profiles in the anteroposterior and mediolateral directions are adopted to approximate the flow field in the anteroposterior channel along the tongue (APT channel). Then, a four-stage Runge-Kutta method is used to calculate the particle trajectories and predict the corresponding filter cake profile by solving the particle motion equations. Finally, the effects of three crucial parameters, i.e. the APT channel widthD_T, the fringe layer permeabilityK, and the food particle diameterd_p, are discussed. The results show that the particle trajectories consist of a series of backward-outward arcs and the food particles tend to accumulate in the posterior region of the oral cavity. The growing parabolic filter cake profiles are formed except for the case of extremely low permeability. A smallD_Tand largeKmake the tendency of particle posterior aggregation obviously. So squeezing the tongue and having larger fringe layer permeability are both conducive to the swallowing process. But the change ind_phas less influence on this tendency. The proposed theoretical analysis method is a fast and low-cost calculation method. The study on the balaenid whales' filter feeding biomechanics and hydrodynamics is helpful to guide the design of the high-efficiency bionic filters.

Allostatic load and the cannabinoid system: implications for the treatment of physiological abnormalities in post-traumatic stress disorder (PTSD)

It is becoming clear that post-traumatic stress disorder (PTSD) is not simply a psychiatric disorder, but one that involves pervasive physiological impairments as well. These physiological disturbances deserve attention in any attempt at integrative treatment of PTSD that requires a focus beyond the PTSD symptoms themselves. The physiological disturbances in PTSD range over many systems, but a common thread thought to underlie them is that the chronic effects of PTSD involve problems with allostatic control mechanisms that result in an excess in what has been termed "allostatic load" (AL). A pharmacological approach to reducing AL would be valuable, but, because of the large range of physiological issues involved - including metabolic, inflammatory, and cardiovascular systems - it is unclear whether there exists a simple comprehensive way to address the AL landscape. In this paper, we propose that the cannabinoid system may offer just such an approach, and we outline evidence for the potential utility of cannabinoids in reducing many of the chronic physiological abnormalities seen in PTSD which are thought to be related to excess AL.