A review on intelligence of cellulose based materials

Cellulose based materials are widely used in various fields such as papermaking, packaging, composite materials, textiles and clothing due to their diverse types, environmental friendliness, natural degradation, high specific strength, and low cost. The intelligence of cellulose based materials will further expand their application fields. This article first gives an in-depth analyzation on the intelligent structural design of these materials according to the two major categories of isotropic and anisotropic, then lists the main preparation methods of cellulose based intelligent materials. Subsequently, this article systematically summarizes the recent intelligent response methods and characteristics of cellulose based materials, and extensively elaborates on the intelligent application of these materials. Finally, the prospects for the intelligence of cellulose based materials are discussed.

Enhancing thromboresistance of neurovascular nickel-titanium devices with responsive heparin hydrogel coatings

BACKGROUND

Neurointerventional devices, particularly laser-cut thin-strut stents made of self-expanding nickel-titanium alloy, are increasingly utilized for endovascular applications in intracranial arteries and dural venous sinuses. Preventing thrombosis and stroke necessitates systemic anticoagulant and antiplatelet therapies with the risk of bleeding complications. Antithrombotic coatings present a promising solution.

METHODS

In this study, we investigated the potential of hydrogels composed of four-armed poly(ethylene glycol) (starPEG) and heparin, with or without coagulation-responsive heparin release, as coatings for neurovascular devices to mitigate blood clot formation. We evaluated the feasibility and efficacy of these coatings on neurovascular devices through in vitro Chandler-Loop assays and implantation experiments in the supra-aortic arteries of rabbits.

RESULTS

Stable and coagulation-responsive starPEG-heparin hydrogel coatings exhibited antithrombotic efficacy in vitro, although with a slightly reduced thromboprotection observed in vivo. Furthermore, the hydrogel coatings demonstrated robustness against shear forces encountered during deployment and elicited only marginal humoral and cellular inflammatory responses compared with the reference standards.

CONCLUSION

Heparin hydrogel coatings offer promising benefits for enhancing the hemocompatibility of neurointerventional devices made of self-expanding nickel-titanium alloy. The variance in performance between in vitro and in vivo settings may be attributed to differences in low- and high-shear blood flow conditions inherent to these models. These models may represent the differences in venous and arterial systems. Further optimization is warranted to tailor the hydrogel coatings for improved efficacy in arterial applications.

Study of mechanical property and biocompatibility of graphene oxide/MEO2MA hydrogel scaffold for wound healing application

Wound healing is a complex biological process crucial for restoring tissue integrity and preventing infections. The development of advanced materials that facilitate and expedite the wound-healing process has been a focal point in biomedical research. In this study, we aimed to enhance the wound-healing potential of hydrogel scaffolds by incorporating graphene oxide and poly (ethylene glycol) methyl ether methacrylate (MEO2MA). Various masses of graphene oxide were added to MEO2MA hydrogels via free radical polymerisation. Comprehensive characterizations, encompassing mechanical properties, and biocompatibility assays, were conducted to evaluate the hydrogels' suitability for wound healing. In vitro experiments demonstrated that the graphene oxide-based hydrogels exhibited a proper swelling degree and tensile strength, responding effectively to moisture conditions and adhesiveness for wound healing. Notably, the tensile strength significantly increased to 626 kPa in the graphene oxide hydrogels. Biocompatibility assessments revealed that the graphene oxide/MEO2MA hydrogels were non-toxic to human dermal fibroblast cell growth, with no significant difference in cell viability observed in the graphene oxide/MEO2MA hydrogel (H-HG) group. In a rat skin experiment, the wound-healing rate of the hydrogel incorporating graphene oxide surpassed that of the pristine hydrogel after a 15-day treatment, achieving over 95% wound closure in the H-HG group. The histopathological analysis further supported the efficacy of the H-HG hydrogel dressing in promoting more effective tissue regeneration. These results collectively highlight the potential of the graphene oxide/MEO2MA hydrogel scaffold as a promising dressing for medical applications.

Penumbra-targeted CircOGDH siRNA-loaded nanoparticles alleviate neuronal apoptosis in focal brain ischaemia

BACKGROUND

Nanoparticles (NPs) are a class of substances that can be loaded with therapeutic agents delivered to specific areas. In our earlier research, we identified a neuron-derived circular RNA (circRNA), circular oxoglutarate dehydrogenase (CircOGDH), as a promising therapeutic target for acute ischaemic stroke. This study dedicated to explore a prospective preliminary strategy of CircOGDH-based NP delivered to the ischaemic penumbra region in middle cerebral artery occlusion/reperfusion (MCAO/R) mice.

METHODS

Immunofluorescence in primary cortex neurons and in vivo fluorescence imaging revealed endocytosis of Poly(lactide-co-glycolide) (PLGA) poly amidoamine(PAMAM)@CircOGDH small interfering RNA (siRNA) NPs. Western blotting analysis and CCK8 assay were performed to evaluate the apoptotic level in ischaemic neurons treated with PLGA-PAMAM@CircOGDH siRNA NPs. Quantitative reverse transcription PCR experiments, mice behaviour test, T2 MRI analysis, Nissl and TdT-mediated dUTP nick end labeling (TUNEL) co-staining were performed to evaluate the apoptosis level of ischaemic penumbra neurons in MCAO/R mice. Biosafety evaluation of NPs in MCAO/R mice was detected by blood routine examination, liver and kidney function examination and HE staining.

RESULTS

PLGA-PAMAM@CircOGDH siRNA NPs were successfully assembled. Endocytosis of PLGA-PAMAM@CircOGDH siRNA NPs in ischaemic neurons alleviated neuronal apoptotic level in vitro and in vivo. Furthermore, mice behaviour test showed that the neurological defects of MCAO/R mice were significantly alleviated after the tail injection of PLGA-PAMAM@CircOGDH siRNA NPs, and no toxic effects were observed.

CONCLUSION

In conclusion, our results suggest that PLGA-PAMAM@CircOGDH siRNA NPs can be delivered to the ischaemic penumbra region and alleviate neuron apoptosis in MCAO/R mice and in ischaemic neurons; therefore, our study provides a desirable approach for using circRNA-based NPs for the treatment of ischaemic stroke.

Material-common and material-specific neural activity during encoding of words and scenes: A neuroimaging meta-analysis

This study examined the extent to which neural activity during memory encoding demonstrates material-commonness or material-specificity. A meta-analysis of functional magnetic resonance imaging studies was conducted to compare the brain regions associated with subsequent memory effects for word and scene stimuli. The main results were as follows. First, significant subsequent memory effects for both words and scenes were primarily observed within the dorsal attention network. This finding aligns with the perspective that temporal fluctuations in attention modulate the intensity of encoding activity, influencing the success and failure of encoding. Second, multiple prefrontal cortex regions, particularly the left inferior frontal cortex, exhibited stronger subsequent memory effects for words compared to scenes. Conversely, multiple visual processing regions revealed an opposite pattern, with heightened subsequent memory effects for scenes relative to words. These findings suggest that words are more strongly encoded through semantic processing, whereas scenes are primarily encoded through visuo-perceptual processing. In conclusion, these results clarify the material specificity and commonness of encoding-related neural activity, emphasizing the significant role of attention and the distinctions between verbal and pictorial information.

A review on life cycle environmental impacts of emerging solar cells

The development of solar technologies requires increased efficiency in converting solar radiation to energy, as well as innovative materials and structure to go beyond the conventional power conversion ratio. In line with these innovations, there are concerns about greenhouse gas emissions of the solar cells, materials for the solar technologies and other relevant environmental impacts of the manufacturing processes. This review is conducted on life cycle assessments of solar cells, considering the climate change and natural resource shortage context. It is identified that the majority of existing life cycle assessments on solar cells take into account four typical environmental impacts: energy consumption, greenhouse gas emissions, material depletion, and toxicity. Though the diverse methodological aspects make it difficult to directly compare these environmental impacts among various types of solar cells, the obtained results hinder that emerging solar cells such as perovskite solar cells or tandem solar cells are likely to have better environmental profiles than conventional silicon based and thin film solar cells, in terms of energy consumption, greenhouse gas emissions and material consumption. However, the emerging solar cells may utilize toxic materials in which their eco-toxicity and human toxicity should be further considered during the design of the technologies. Moreover, it is identified that the energy and environmental hotspot lies in the manufacturing process, regardless of impact indicators and types of solar cells.

Pros and Cons in Various Immobilization Techniques and Carriers for Enzymes

In recent years, enzyme immobilization technology has been developed, and studies on immobilized enzyme materials have become very prominent. With the immobilization technique, enzymes and compatible carrier materials are combined or enzyme crystals/aggregates are used in a carrier-free fashion, by physical, chemical, or biochemical methods. As a kind of biocatalyst, immobilized enzymes can catalyze certain chemical reactions with high selectivity and high efficiency under relatively mild reaction conditions and eliminate pollution to the environment. Considering the current status and applications of immobilized enzyme technology and materials emerging in the last 5 years, this mini-review introduces the advantages and disadvantages of various enzyme immobilization techniques with carriers as well as the pros and cons of different materials for immobilization. The future prospects of immobilization technology and carrier materials are outlined, aiming to provide a reference for further research and applications of sustainable technology.

Peripheral intravenous catheter material and design to reduce device failure: A systematic review and meta-analysis

BACKGROUND

Patients require vascular access for medical treatments, diagnostic procedures and symptom management. Current failure rates of peripheral intravascular catheters (PIVCs) are unacceptably high (40-50%). This systematic review aimed to determine the effect of different PIVC materials and designs on the incidence of PIVC failure.

METHODS

A systematic search was conducted in November 2022 using CINAHL, PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases. Randomised controlled trials that compared PIVC novel PIVC material/design and standard material/design were included. The primary outcome was all causes of PIVC failure, any reason for device removal due to cessation of device function; and secondary outcomes included individual PIVC complications and infection (local or systemic), and dwell times. Quality appraisal was conducted using the Cochrane risk of bias tool. A meta-analysis was performed using random effects model.

RESULTS

Seven randomised controlled trials were eligible for inclusion. In meta-analysis, the impact of material and design on PIVC failure in the studies favoured the intervention arms (RR 0.71, 95% CI 0.57-0.89), however there was substantial heterogeneity (I2 = 81%, 95% CI 61-91%). Through subgroup analyses, a significant difference on PIVC failure favoured the closed system over the open system (RR 0.85, 95% CI 0.73 to 0.99; I2 = 23%, 95% CI 0-90%).

CONCLUSION

Catheter material and design can impact PIVC outcome. Conclusive recommendations are limited due to the small number of studies and inconsistent reporting of clinical outcomes. Further rigorous research of PIVC types is necessary to improve clinical practice and device selection pathways should reflect the resulting evidence.

The potential of industry 4.0 for renewable energy and materials development - The case of multinational energy companies

The study's primary objective is to identify the implications of Industry 4.0 (I4.0) implementation for renewable energy management and materials development. The study aims to establish a new perspective that promotes adopting emerging clean energy technologies. The study adopts a transdisciplinary approach and critical synthesis of existing literature. Thematic analysis and inferences from three case illustrations are used to gain insights into the value and strategies of I4.0 implementation for achieving a sustainable and low-carbon future. The literature review on I 4.0 provides a deeper understanding of its concepts and potential benefits. The study highlights the improved efficiency, productivity, and sustainability that I4.0 technologies, such as IoT, AI, and advanced manufacturing, can bring to various industries. The study's findings have significant implications for the practical implementation of I4.0. By cohesively identifying and addressing economic, regulatory, and technical obstacles, I4.0 can be effectively implemented for renewable energy and materials development. The study is a valuable reference for students, researchers, scholars, and practitioners. It may guide the design and implementation of I4.0 strategies and supports the transition toward a sustainable and low-carbon future.

Current status and future prospects of stomatology research

Research in stomatology (dental medicine) continues to expand globally and is oriented towards solving clinical issues, focusing on clarifying the clinical relevance and potential mechanisms of oral‍-‍systemic connections via clinical epidemiology, oral microecological characterization, and the establishment of animal models. Interdisciplinary integration of materials science and tissue engineering with stomatology is expected to lead to the creation of innovative materials and technologies to better resolve the most prevalent and challenging clinical issues such as peri-implantitis, soft and hard tissue defects, and dentin hypersensitivity. With the rapid development of artificial intelligence (AI), 5th generation mobile communication technology (5G), and big data applications, "intelligent stomatology" is emerging to build models for better clinical diagnosis and management, accelerate the reform of education, and support the growth and advancement of scientific research. Here, we summarized the current research status, and listed the future prospects and limitations of these three aspects, aiming to provide a basis for more accurate etiological exploration, novel treatment methods, and abundant big data analysis in stomatology to promote the translation of research achievements into practical applications for both clinicians and the public.

Study on degradation of cooking fume by compound filter material and UV photodegradation

Environmental contamination issues have steadily surfaced with the rapid development of the cooking industry. In this paper, the front end of the cooking fume exhaust was filtered by the filter material, and then, the ultraviolet photolysis technology was used for in-depth treatment. The filter material filtration performance of glass fiber, molecular sieve, and composite filter material was studied by the filter efficiency, filter resistance, and quality factor three filter performance indexes. The results show that the filter wind speed has a significant influence on the filter material fume filtration characteristics. The filtration efficiency of the pre-filter material changes the least with the increase of the wind speed when the wind speed is 18 m·s^-1 and the filter material tilt Angle is 60°; meanwhile, the pressure drop of the two kinds of filter material is reduced, and the quality factor is improved. Under the optimal wind speed and angle, the composite filter material of glass fiber and molecular sieve combined with UV photolysis technology was used to study the treatment of formaldehyde and acrolein, which are two volatile organic pollutants with high content in cooking fume, and the mineralization mechanism of formaldehyde and acrolein under UV light was analyzed. The results showed that the removal rates of formaldehyde and acrolein could reach 99.84% and 99.75%, respectively.

You can touch this! Brain correlates of aesthetic processing of active fingertip exploration of material surfaces

The haptic exploration and aesthetic processing of all kinds of materials' surfaces are part of everyday life. In the present study, functional near-infrared spectroscopy (fNIRS) was used to investigate the brain correlates of active fingertip exploration of material surfaces and subsequent aesthetic judgments of their pleasantness (feels good or bad?). In absence of other sensory modalities, individuals (n = 21) performed lateral movements on a total of 48 textile and wood surfaces varying in terms of their roughness. Behavioral results confirmed the influence of the stimuli's roughness on aesthetic judgments, with smoother textures being rated as feeling better than rough textures. At the neural level, fNIRS activation results revealed an overall increased engagement of the contralateral sensorimotor areas as well as left prefrontal areas. Moreover, the perceived pleasantness modulated specific activations of left prefrontal areas with increasing pleasantness showing greater activations of these regions. Interestingly, this positive relationship between the individual aesthetic judgments and brain activity was most pronounced for smooth woods. These results demonstrate that positively valenced touch by actively exploring material surfaces is linked to left prefrontal activity and extend previous findings of affective touch underlying passive movements on hairy skin. We suggest that fNIRS can be a valuable tool to provide new insights in the field of experimental aesthetics.

Distal cerebral vasospasm treatment following aneurysmal subarachnoid hemorrhage using the Comaneci device: technical feasibility and single-center preliminary results

BACKGROUND

Balloon-assisted mechanical angioplasty for cerebral vasospasm following aneurysmal subarachnoid hemorrhage (aSAH) has a number of limitations, including transient occlusion of the spastic blood vessel. Comaneci is an FDA-approved device for temporary coil embolization assistance which has recently also been approved for the treatment of distal symptomatic refractory vasospasm. We aimed to report the feasibility, efficacy and safety of our experience with Comaneci angioplasty for refractory distal vasospasm (up to the second segment of the cerebral arteries) following aSAH.

METHODS

This is a retrospective analysis of a prospective series of 18 patients included between April 2019 and June 2021 with aSAH and symptomatic vasospasm refractory to medical therapy, who were treated using Comaneci-17-asssisted mechanical distal angioplasty. Immediate angiographic results, procedure-related complications, and clinical outcomes were assessed. Inter-rater reliability of the scores was determined using the intraclass correlation coefficient.

RESULTS

Comaneci-assisted distal angioplasty was performed in 18 patients, corresponding to 31 target arteries. All distal anterior segments were easily accessible with the Comaneci-17 device. Vasospasm improvement after Comaneci mechanical angioplasty was seen in 22 distal arteries (71%) (weighted Cohen's kappa (κ_w) 0.73, 95% CI 0.69 to 0.93). Vasospasm recurrence occurred in three patients (16.67%) and delayed cerebral infarction in three patients (16.67%), with a mean±SD delay between onset of symptoms and imaging follow-up (MRI/CT) of 32.61±8.93 days (κ_w 0.98, 95% CI 0.88 to 1).

CONCLUSION

This initial experience suggests that distal mechanical angioplasty performed with the Comaneci-17 device for refractory vasospasm following aSAH seems to be safe, with good feasibility and efficacy.

A Review of Challenges and Opportunities for Microbially Removing 1,4-Dioxane to Meet Drinking-Water and Groundwater Guidelines

1,4-Dioxane is an emerging contaminant in drinking-water sources and contaminated sites. Microbial removal of 1,4-dioxane has attracted a lot of attention, but faces a challenge: being not able to continuously metabolize 1,4-dioxane to below most drinking-water and groundwater guidelines. The 1,4-dioxane concentrations in most drinking-water sources and contaminated sites are too low to sustain biomass growth. This minireview discusses strategies that may potentially address the challenge. The strategies include: 1) finding oligotrophs for which the minimum 1,4-dioxane concentrations to sustain biomass are low, 2) determining conditions that maximize 1,4-dioxane co-metabolism or co-oxidation, 3) creating novel materials as biomass carriers and contaminant concentrators, and 4) lowering the life-cycle costs of technologies that combine biodegradation with (electro)chemical oxidation or phytoremediation.

Bioresorbable flow diverters for the treatment of intracranial aneurysms: review of current literature and future directions

The use of flow diverters is a rapidly growing endovascular approach for the treatment of intracranial aneurysms. All FDA-approved flow diverters are composed of nitinol or cobalt-chromium, which will remain in the patient for the duration of their life. Bioresorbable flow diverters have been proposed by several independent investigators as the next generation of flow diverting devices. These devices aim to serve their transient function of occluding and healing the aneurysm prior to being safely resorbed by the body, eliminating complications associated with the permanent presence of conventional flow diverters. Theoretical advantages of bioresorbable flow diverters include (1) reduction in device-induced thrombosis; (2) reduction in chronic inflammation and device-induced stenosis; (3) reduction in side branch occlusion; (4) restoration of physiological vasomotor function; (5) reduction in imaging artifacts; and (6) use in pediatric applications. Advances made in the similar bioresorbable coronary stenting field highlight some of these advantages and demonstrate the feasibility and safety of bioresorbable endovascular devices in the clinic. The current work aims to review the progress of bioresorbable flow diverters, identify opportunities for further investigation, and ultimately stimulate the advancement of this technology.

Use of Conventional Cigarette Smoking and E-Cigarette Vaping for Experimental Stroke Studies in Mice

Cigarette smoking is a major prodromal factor for the onset of many adverse health effects that may occur in the short run and is the leading cause of preventable disease, disability, and death in the United States. Moreover, it is well established that chronic smoking is associated with vascular endothelial dysfunction in a causative and dose-dependent manner primarily related to the release of reactive oxygen species (ROS), nicotine, and the induction of oxidative stress (OS)-driven inflammation. Preclinical studies have also shown that nicotine (the principal e-liquid ingredient used in e-cigarettes) can also cause OS, exacerbating cerebral ischemia and secondary brain injury. Likewise, chronic e-Cig vaping could be prodromal to cerebrovascular impairment and promote cerebrovascular conditions favoring stroke onset and worsening post-ischemic brain injury. Therefore, using mouse models is crucial to understand how xenobiotics such as those released by conventional and/or e-cigs can impact the onset and severity of stroke as well as post-stroke recovery. To appropriately model human-like smoking/vaping behavior in mice, however, the exposure to these xenobiotics must be standardized and undertaken in a controlled environment. This chapter describes a well-validated protocol to reproduce standardized chronic tobacco smoke or e-cigarette vape exposure in mice in the setting of a mouse transient ischemic stroke model.

Research status, challenges and future prospects of renewable synthetic fuel catalysts for CO2 photocatalytic reduction conversion

In recent years, with global climate change, the utilization of carbon dioxide as a resource has become an important goal of human society to achieve carbon peaking and carbon neutrality. Among them, the catalytic conversion of carbon dioxide to generate renewable fuels has received great attention. As one of these methods, photocatalysis has its unique properties and mechanism, which can only rely on sunlight without inputting other energy. It is an emerging discipline with great development prospects. The core of photocatalysis lies in the development of photocatalysts with high activity, high selectivity, low cost, and high durability. This review first introduces the background and mechanism of photocatalysis, then introduces various types of photocatalysts based on different substrates, and analyzes the methods and mechanisms to improve the activity and selectivity of photocatalysts. Finally, combining the plasmon effect with photocatalysis, the review analyzes the promoting effect of the plasmon effect on the photocatalytic carbon dioxide synthesis of renewable fuels, which provides a new idea for it.

Biomechanical comparison of different rod-to-rod connectors to a conventional titanium- and cobalt chromium posterior spinal fixation system

Introduction

Several types of rod-to-rod connectors are available for the extension of spinal fixation systems. However, scientific literature regarding the mechanical performance of different rod-to-rod connector systems is lacking.

Research question

The goal of this study was to evaluate the mechanical characteristics of axial and lateral rod connectors in comparison to a conventional pedicle screw rod (titanium and cobalt chromium) construct.

Material and method

Six types of instrumentations were investigated in a standardized test model to quantify the mechanical differences: 1: titanium rod; 2: titanium rod with axial connector; 3: titanium rod with lateral connector; 4: cobalt chromium rod; 5: cobalt chromium rod with axial connector; 6: cobalt chromium rod with lateral connector. All groups were tested in static compression, static torsion and dynamic compression and statistically compared regarding failure load and stiffness.

Results

In static compression loading, the use of connectors increased the construct stiffness, but unaffected the yield load. The use of a cobalt chromium rod significantly increased by approximately 40% the yield load and stiffness in comparison to the titanium rod configurations. Under dynamic compression, a similar or higher fatigue strength for all tested groups in comparison to the titanium rod configuration was evaluated, with the exception of titanium rod with axial connector.

Conclusion

Biomechanically, using rod connectors is a secure way for the extension of a construct and is mechanically equal to a conventional screw rod construct. However, in clinical use, attention should be paid regarding placement of the connectors at high loaded areas.

Optimization of soil microbial fuel cell for sustainable bio-electricity production: combined effects of electrode material, electrode spacing, and substrate feeding frequency on power generation and microbial community diversity

BACKGROUND

Microbial fuel cells (MFCs) are among the leading research topics in the field of alternative energy sources due to their multifunctional potential. However, their low bio-energy production rate and unstable performance limit their application in the real world. Therefore, optimization is needed to deploy MFCs beyond laboratory-scale experiments. In this study, we investigated the combined influence of electrode material (EM), electrode spacing (ES), and substrate feeding interval (SFI) on microbial community diversity and the electrochemical behavior of a soil MFC (S-MFC) for sustainable bio-electricity generation.

RESULTS

Two EMs (carbon felt (CF) and stainless steel/epoxy/carbon black composite (SEC)) were tested in an S-MFC under three levels of ES (2, 4, and 8 cm) and SFI (4, 6, and 8 days). After 30 days of operation, all MFCs achieved open-circuit voltage in the range of 782 + 12.2 mV regardless of the treatment. However, the maximum power of the SEC-MFC was 3.6 times higher than that of the CF-MFC under the same experimental conditions. The best solution, based on the interactive influence of the two discrete variables, was obtained with SEC at an ES of 4.31 cm and an SFI of 7.4 days during an operating period of 66 days. Analysis of the experimental treatment effects of the variables revealed the order SFI < ES < EM, indicating that EM is the most influential factor affecting the performance of S-MFC. The performance of S-MFC at a given ES value was found to be dependent on the levels of SFI with the SEC electrode, but this interactive influence was found to be insignificant with the CF electrode. The microbial bioinformatic analysis of the samples from the S-MFCs revealed that both electrodes (SEC and CF) supported the robust metabolism of electroactive microbes with similar morphological and compositional characteristics, independent of ES and SFI. The complex microbial community showed significant compositional changes at the anode and cathode over time.

CONCLUSION

This study has demonstrated that the performance of S-MFC depends mainly on the electrode materials and not on the diversity of the constituent microbial communities. The performance of S-MFCs can be improved using electrode materials with pseudocapacitive properties and a larger surface area, instead of using unmodified CF electrodes commonly used in S-MFC systems.

Impact of Ureteral Stent Material on Stent-related Symptoms: A Systematic Review of the Literature

Context

Ureteral stents are essential implants that are used on a daily basis. Since their invention, advances in stent design have been directed towards alleviating stent-related symptoms. It remains unclear how the material composition of the stent affects stent-related symptoms.

Objective

To review the literature and define the clinical impact of ureteral stent material on stent-related symptoms.

Evidence acquisition

A literature search of the Embase, MEDLINE (PubMed), and Web of Science databases was conducted on December 17, 2021 to collect articles comparing stent composition materials regarding stent-related symptoms. Thirteen publications met the inclusion criteria, of which only one met the high-quality requirements of the Cochrane Collaboration tool for assessing the risk of bias in randomized trials.

Evidence synthesis

Most trials, including the highest quality trial, seem to support that silicone double-J (DJ) stents reduce stent-related symptoms compared to nonsilicone DJ stents. Regarding physical properties, it seems that “soft” or “flexible” DJ stents reduce stent-related symptoms. However, since there was only one high-quality study with a low risk of bias, it is impossible to draw a definitive conclusion owing to the lack of quality data.

Conclusions

Silicone DJ stents, and by extension “soft” DJ stents, appear to reduce stent-related symptoms compared to nonsilicone polymers and “hard” DJ stents. No definitive conclusion can be drawn owing to a lack of quality evidence. Creating a standard for measuring and reporting physical stent properties should be the first step for further research.

Patient summary

A ureteral stent is a small hollow tube placed inside the ureter to help urine drain from the kidney. We reviewed the literature on the impact of stent material on stent-related symptoms. We found that silicone may reduce stent-related symptoms, but no definitive conclusion can be drawn and further studies are needed.

The nano delivery systems and applications of mRNA

The current COVID-19 epidemic has greatly accelerated the application of mRNA technology to our real world, and during this battle mRNA has proven it's unique advantages compared to traditional biopharmaceutical and vaccine technology. In order to overcome mRNA instability in human physiological environments, mRNA chemical modifications and nano delivery systems are two key factors for their in vivo applications. In this review, we would like to summarize the challenges for clinical translation of mRNA-based therapeutics, with an emphasis on recent advances in innovative materials and delivery strategies. The nano delivery systems include lipid delivery systems (lipid nanoparticles and liposomes), polymer complexes, micelles, cationic peptides and so on. The similarities and differences of lipid nanoparticles and liposomes are also discussed. In addition, this review also present the applications of mRNA to other areas than COVID-19 vaccine, such as infectious diseases, tumors, and cardiovascular disease, for which a variety of candidate vaccines or drugs have entered clinical trials. Furthermore, mRNA was found that it might be used to treat some genetic disease, overcome the immaturity of the immune system due to the small fetal size in utero, treat some neurological diseases that are difficult to be treated surgically, even be used in advancing the translation of iPSC technology et al. In short, mRNA has a wide range of applications, and its era has just begun.

Systematic review and meta-analysis for the impact of rod materials and sizes in the surgical treatment of adolescent idiopathic scoliosis

PURPOSE

To assess surgical and safety outcomes associated with different rod materials and diameters in adolescent idiopathic scoliosis (AIS) surgery.

METHODS

A systematic literature review and meta-analysis evaluated the surgical management of AIS patients using pedicle screw fixation systems (i.e., posterior rods and pedicle screws) with rods of different materials and sizes. Postoperative surgical outcomes (e.g., kyphosis and coronal correction) and complications (i.e., hyper/hypo-lumbar lordosis, proximal junctional kyphosis, revisions, reoperations, and infections) were assessed. Random-effects models (REMs) pooled data for outcomes reported in ≥ 2 studies.

RESULTS

Among 75 studies evaluating AIS surgery using pedicle screw fixation systems, 46 described rod materials and/or diameters. Two studies directly comparing titanium (Ti) and cobalt-chromium (CoCr) rods found that CoCr rods provided significantly better postoperative kyphosis angle correction vs. Ti rods during a shorter follow-up (0-3 months, MD = - 2.98°, 95% CI - 5.79 to - 0.17°, p = 0.04), and longer follow-up (≥ 24 months, MD = - 3.99°, 95% CI - 6.98 to - 1.00, p = 0.009). Surgical infection varied from 2% (95% CI 1.0-3.0%) for 5.5 mm rods to 4% (95% CI 2.0-7.0%) for 6 mm rods. Reoperation rates were lower with 5.5 mm rods 1% (95% CI 0.0-3.0%) vs. 6 mm rods [6% (95% CI 2.0-9.0%); p = 0.04]. Differences in coronal angle, lumbar lordosis, proximal junctional kyphosis, revisions, and infections did not differ significantly (p > 0.05) among rods of different materials or diameters.

CONCLUSION

For AIS, CoCr rods provided better correction of thoracic kyphosis compared to Ti rods. Patients with 5.5 mm rods had fewer reoperations vs. 6.0 and 6.35 mm diameter rods.

LEVEL OF EVIDENCE

III.

Sonoproduction of nanobiomaterials - A critical review

Ultrasound (US) demonstrates remarkable potential in synthesising nanomaterials, particularly nanobiomaterials targeted towards biomedical applications. This review briefly introduces existing top-down and bottom-up approaches for nanomaterials synthesis and their corresponding synthesis mechanisms, followed by the expounding of US-driven nanomaterials synthesis. Subsequently, the pros and cons of sono-nanotechnology and its advances in the synthesis of nanobiomaterials are drawn based on recent works. US-synthesised nanobiomaterials have improved properties and performance over conventional synthesis methods and most essentially eliminate the need for harsh and expensive chemicals. The sonoproduction of different classes and types of nanobiomaterials such as metal and superparamagnetic nanoparticles (NPs), lipid- and carbohydrate-based NPs, protein microspheres, microgels and other nanocomposites are broadly categorised based on the physical and/or chemical effects induced by US. This review ends on a good note and recognises US-driven synthesis as a pragmatic solution to satisfy the growing demand for nanobiomaterials, nonetheless some technical challenges are highlighted.

Human pressure tolerance and effects of different padding materials with implications for development of exoskeletons and similar devices

In this study, we assessed pressure tolerance in 16 healthy participants at the thigh, chest, and pelvic area, using different surfaces (1 cm², 20 cm² and different components, used in exoskeleton design), and the effects of different padding materials. Our results showed substantial variability in pressure tolerance among the participants, as well as lower pressure tolerance in females. Regarding the force applied with the exoskeleton components, male participants had higher discomfort threshold (230.3 ± 44.9 N compared to females (116.1 ± 24.6 N) in the chest area. For the applications with 20 cm² surface, the males also showed higher pain threshold at the thigh (89.3 ± 41.8 N vs. 34.6 ± 27.2 N) and the pelvis (97.6 ± 37.0 N vs. 56.1 ± 29.5 N). All padding materials increased pressure tolerance for 10-38% (p < 0.001), but little differences between materials were observed.

Considering the influence of heating rate, complex hardening and dynamic strain aging in AISI 1045 machining: experiments and simulations

In the modelling of machining operations, constitutive models must consider the material behavior subject to high plastic strains, high strain rates, high temperatures and high heating rates. A new material model for AISI 1045, which captures time-dependent plastic response associated with interrupted austenite transformation under short (sub-second) heating times, is deployed to simulate orthogonal cutting experiments. High speed video and digital image correlation measurements are used to capture chip behavior. The new model, which also includes complex strain hardening and dynamic strain aging effects, show better agreement with experiments at high cutting speeds compared with a basic Johnson-Cook material model from the literature.

Factors contributing to stability and instability in alpha-amylase activity in diluted saliva samples over time

For the measurement of salivary alpha-amylase (sAA) activity, saliva samples first have to be diluted. There is some evidence for instability, that is, a decline of sAA activity in diluted samples. It is not clear which factors during dilution may contribute to this phenomenon and how quickly this decline of sAA activity occurs. Several experiments were conducted to investigate whether and how the material of the container (polystyrene (PS), polypropylene (PP), glass; experiment 1) and the diluent (saline (NaCl) solution, phosphate buffer saline (PBS), ultra-pure water; experiment 2) may affect sAA stability in diluted samples over a broad time window of up to 5 h. To study the velocity of the phenomenon in a fine-grained temporal resolution, sAA activity during the dilution process was studied (experiment 3). The results suggest that the (in)stability of sAA activity in diluted samples is determined by the interaction of material, diluent, and time. The sAA activity was relatively stable if saliva samples were diluted with a NaCl solution or PBS in glass tubes. However, sAA activity in diluted samples decreased in plastic containers (PS, PP), or if ultra-pure water was used as the diluent. There was a clear time effect on this decline. However, the decline appears to require some time to evolve and may not occur immediately during the dilution process. To conclude, the dilution of saliva samples should preferably be conducted with NaCl solution or PBS in glass containers. If glass containers are not available, PS and PP containers can be used if the dilution is processed quickly (within 25 min) and the measurement is initiated immediately upon dilution.

The valorisation of residual waste bales by urban mining

In the last decade, the approach to waste management has undergone severe changes. The urgent need to face the sustainable demand for energy and materials while limiting the burdens associated to traditional waste handling practices have figured out the concept of waste as a resource. New strategies boosting the extensive recovery and diverting waste from disposal activities have been promoted and framed in the wider context of the urban mining, promoting the full exploitation of waste as resource for either new materials or energy production. Such approach has been recently proposed to handle over 5 million tons of pretreated municipal solid waste produced and stored in the form of bales in Campania Region, in southern Italy, between 2000 and 2009. However, since the feasibility of this approach is related to the waste composition as well as to the selection process, an experimental study was performed at an industrial mechanical treatment plant to assess the potential for valorisation of this waste. Results showed that the overall sustainability of the urban mining strategies for the management of Campania waste bales is tightly linked to the flexibility of the selection process scheme to be adopted, which should make the waste recovery fit the market demand of either material or energy.

Miniaturized high-throughput synthesis and screening of responsive hydrogels using nanoliter compartments

The traditional pipeline of hydrogel development includes individual one-by-one synthesis and characterization of hydrogels. This approach is associated with the disadvantages of low-throughput and high cost. As an alternative approach to classical one-by-one synthesis, high-throughput development of hydrogels is still tremendously under-represented in the field of responsive material development, despite the urgent requirement for such techniques. Here, we report a platform that combines highly miniaturized hydrogel synthesis with screening for responsive properties in a high-throughput manner. The platform comprises a standard glass slide patterned with 1 ​× ​1 ​mm hydrophilic regions separated by superhydrophobic liquid-impermeable barriers, thus allowing deposition of various precursor solutions onto the hydrophilic spots without cross-contamination. The confinement of these solutions provided by the hydrophilic/superhydrophobic pattern allows encapsulation of cells within the hydrogel, and enables variation in hydrogel height and width. We have also proved the proper mixing of chemicals within the nanoliter-sized droplets. We have successfully implemented this platform for the synthesis of hydrogels, constructing 53 unique hydrogels, to demonstrate the versatility and utility of the platform. Photodegradation studies were performed on 20 hydrogels, revealing structure/function relationships between the hydrogel composition and photodegradability, and covering the range of degradability from non-degradable to rapidly degradable materials.

Octacalcium phosphate collagen composite (OCP/Col) enhance bone regeneration in a rat model of skull defect with dural defect

Cranial bone defects are a major issue in the field of neurosurgery, and improper management of such defects can cause cosmetic issues as well as more serious infections and inflammation. Several strategies exist to manage these defects clinically, but most rely on synthetic materials that are prone to complications; thus, a bone regenerative approach would be superior. We tested a material (octacalcium phosphate collagen composite [OCP/Col]) that is known to enhance bone regeneration in a skull defect model in rats. Using a critical-sized rat skull defect model, OCP/Col was implanted in rats with an intact dura or with a partial defect of the dura. The results were compared with those in a no-treatment group over the course of 12 weeks using computed tomographic and histological analysis. OCP/Col enhanced bone regeneration, regardless of whether there was a defect of the dura. OCP/Col can be used to treat skull defects, even when the dura is injured or removed surgically, via bone regeneration with enhanced resorption of OCP/Col, thus limiting the risk of infection greatly.

Hardware removal rates after surgical treatment of proximal femur fractures : Nationwide trends in Finland in 1997-2016

BACKGROUND

Various internal fixation methods have been used to treat proximal femur fractures and occasionally the fixation material is removed. However, nationwide trends of hardware removals are not known. Thus, this study investigated the hardware removal rates after proximal femur fractures in Finland during 1997-2016.

MATERIALS AND METHODS

Finnish adults aged 18 years or older in 1997-2016 formed the basic study population. From the National Hospital Discharge Register patients with trochanteric femur fracture treated with an intramedullary nail (IMN) or dynamic hip screw (DHS), and patients with femoral neck fracture treated with screw fixation, were included. Hardware removal and secondary prosthesis rates were assessed.

RESULTS

Altogether 41,253 patients underwent proximal femoral fracture fixation surgery in Finland in 1997-2016. Of these, 16,152 were DHS surgery and 15,724 IMN surgery and 8491 underwent screw operation of femoral neck fracture. The total removal rates of DHS and IMN were 5.5% and 5.4%. The total removal rate of screw fixations of the femoral neck was higher, 18.5%. The total removal rates during the first 3 years after the IMN more than halved in 1997-2013, from 7.6% to 3.7%, whereas the removal rate of the DHS or screw fixation of femoral neck fractures did not show consistent trend. The rate of secondary prosthesis operations following DHS and IMN was low (1.8% for both). This was in clear contrast to the prosthesis rate following screw fixations of the femoral neck (7.2%).

CONCLUSIONS

IMN operations largely replaced DHS operations in trochanteric fractures of the proximal femur in Finland in 1997-2016. The removal and secondary prosthesis rates of the DHS and IMN were clearly lower than the corresponding rates after screw fixations of the femoral neck fracture.

LEVEL OF EVIDENCE

III, Epidemiologic study.

Biomechanical comparison between stainless steel, titanium and carbon-fiber reinforced polyetheretherketone volar locking plates for distal radius fractures

INTRODUCTION

As the popularity of volar locked plate fixation for distal radius fractures has increased, so have the number and variety of implants, including variations in plate design, the size and angle of the screws, the locking screw mechanism, and the material of the plates.

HYPOTHESIS

Carbon-fiber reinforced polyetheretherketone (CFR-PEEK) plate features similar biomechanical properties to metallic plates, representing, therefore, an optimal alternative for the treatment of distal radius fractures.

MATERIALS AND METHODS

Three different materials-composed plates were evaluated: stainless steel volar lateral column (Zimmer); titanium DVR (Hand Innovations); CFR-PEEK DiPHOS-RM (Lima Corporate). Six plates for each type were implanted in sawbones and an extra-articular rectangular osteotomy was created. Three plates for each material were tested for load to failure and bending stiffness in axial compression. Moreover, 3 constructs for each plate were evaluated after dynamically loading for 6000 cycles of fatigue.

RESULTS

The mean bending stiffness pre-fatigue was significantly higher for the stainless steel plate. The titanium plate yielded the higher load to failure both pre and post fatigue. After cyclic loading, the bending stiffness increased by a mean of 24% for the stainless steel plate; 33% for the titanium; and 17% for the CFR-PEEK plate. The mean load to failure post-fatigue increased by a mean of 10% for the stainless steel and 14% for CFR-PEEK plates, whereas it decreased (-16%) for the titanium plate. Statistical analysis between groups reported significant values (p<001) for all comparisons except for Hand Innovations vs. Zimmer bending stiffness post fatigue (p=.197).

DISCUSSION

The significant higher load to failure of the titanium plate, makes it indicated for patients with higher functional requirements or at higher risk of trauma in the post-operative period. The CFR-PEEK plate showed material-specific disadvantages, represented by little tolerance to plastic deformation, and lower load to failure.

LEVEL OF EVIDENCE

N/A.

Impact of test protocols and material binding on the efficacy of antimicrobial wipes

BACKGROUND

The use of effective cleaning/disinfectant products is important to control pathogens on healthcare surfaces. With the increasing number of wipe products available, there is a concern that combination of a formulation with the wrong material will decrease the efficacy of the product. This study aimed to use a range of efficacy test protocols to determine the efficacy of four formulations before and after binding to three commonly used wiping materials.

METHODS

Two quaternary ammonium (QAC)-based products, one hydrogen-peroxide-based product and one neutral cleaner were combined with microfibre, cotton or non-woven materials and tested for efficacy against Pseudomonas aeruginosa and Staphylococcus aureus with two surface tests (ASTM E2197-17 and EN13697-15) and two 'product' tests (ASTM E2967-15 and EN16615-15).

FINDINGS

Overall, the impact of using different materials on formulation efficacy was limited, except for an alkyl(C_12-16)dimethylbenzylammonium chloride-based product used at 0.5% v/v. The hydrogen peroxide product was the most efficacious regardless of the material used. The results from wipe test ASTM E2967-15 were consistent with those from the surface tests, but not with EN16615-15 which was far less stringent.

CONCLUSIONS

The use of different wiping cloth materials may not impact severely on the efficacy of potent disinfectants, despite the absorption of different volumes of formulation by the materials. QAC-based formulations may be at higher risk when a low concentration is used. There were large differences in efficacy depending on the standard test performed, highlighting the need for more stringency in choosing the test to make a product claim on label.

Nickel-Related Adverse Reactions in the Treatment of Cerebral Aneurysms: A Literature Review

BACKGROUND

Nickel is the most common metal allergen and predominantly affects women. It is also the ubiquitous component in the alloys used to manufacture intracranial devices for aneurysm treatments, including aneurysm clips, self-expanding stents, flow-diverting stents, and endosaccular occlusion devices. Adverse events related to nickel allergy after deployment of such devices are uncommon but can be severe, resulting in dilemmas in the choice of treatment strategies and devices in managing nickel-sensitive patients with intracranial aneurysms.

METHODS

A literature search was performed in accordance with the PRISMA guidelines to identify studies reporting on nickel-related adverse events in patients being treated for cerebral aneurysm. The materials of the culprit devices, clinical presentation, histological features, and treatments were reviewed. Clinical considerations and management options for nickel allergy patients were evaluated.

RESULTS

Nickel is a major component of the cobalt alloy used in aneurysm clips and also of nitinol, which is commonly used in flow diverters and intracranial stents. Our literature review identified 9 articles reporting 10 unique cases of nickel-related adverse events after aneurysm treatment. Five of the cases occurred after aneurysm clipping, and the other 5 were attributed to endovascular devices. Two patients presented with dermatologic manifestations and 8 with neurologic manifestations, including cerebral edema and cerebritis.

CONCLUSIONS

Neurologic complications related to nickel in cerebral aneurysm treatments are rare but remain concern owing to the high prevalence of nickel allergy in the population. Surgeons and interventionists should consider the metal allergy history and its potential clinical significance in managing nickel-allergic patients with aneurysms.

[Surface modifications of implants. Part 2 : Clinical application]

The chemical composition, surface structure and topography of a biomaterial have an essential influence on the effects of an implant in the human body. In orthopedic and trauma surgery they make a relevant contribution to solve the current and future challenges. Particularly high are the requirements of permanent implants in bone. Besides material aging due to oxidation, implants are subjected to cyclic loading that leads to relevant biomechanical wear and abrasion. To date significant efforts have been made to minimize adverse implant-associated immunoreactions as well as the risk of periprosthetic infections. This review gives an overview of surface modifications of implants designed for clinical application and their effects in vivo. Beside material-specific and biological principles, different surface modifications for distinct clinical applications are presented. Furthermore, current developmental strategies for the targeted clinical application of implant surfaces are outlined.

[Surface modifications of implants. Part 1 : Material technical and biological principles]

The biological effects of implants in vivo are not only dependent on the implantation site and patient-specific factors but are also influenced by the physicochemical composition and the surface topography of the biomaterial. In cases of permanent implants applied to bone, primary stability, the promotion of rapid osteointegration and antimicrobial properties of the implant are strived for; however, surface modifications are also found on biomaterials which only temporarily come into contact with tissue. These include not only osteosynthesis materials, jig or implant templates but also surgical instruments. This article summarizes the relevant technical principles of materials for the assessment of implant surfaces. Besides technical material-specific and biological principles, different surface modifications for targeted clinical applications are presented. Furthermore, current developmental strategies are outlined.

Advances in Ureteral Stent Design and Materials

Purpose of Review

There are three technological parameters that play a key role on the performance of an ideal stent. These are its material, design and surface coating. This article highlights some fundamental developments that took place in these three areas of stent’s technology, in order to contribute to the identification of an ideal stent.

Recent Findings

In addition to technological developments concerning stent’s material, design and surface coating, the flow dynamic performance of stents has recently attracted increasing attention. Notably, it has been postulated that the local flow field in a stent is correlated with the deposition of crystals and microorganisms. These findings could potentially revolutionise future stent’s designs, and complement developments made on materials and coatings.

Summary

The most relevant changes in materials, designs and surface coatings of ureteric stents are reviewed in this article. These are described in the context of a specific cause of stent’s failure they aim to address, with a particular focus on encrustation and biofilm formation.

A randomized study of four different types of tympanostomy ventilation tubes - Full-term follow-up

OBJECTIVE

To evaluate the impact of tympanostomy ventilation tube material (silicone vs fluoroplastic) and shape (short vs long) regarding time to extrusion, occurrence of otorrhea, occlusion, tube removal and occurrence of persistent perforation.

METHODS AND MATERIAL

Four different types of ventilation tubes were used; Long Armstrong tubes, Donaldson tubes, Shepard tubes and straight tubes, representing four specific combinations of VT material (silicone or fluoroplastic) and shape (short, double flanged or long, single flanged). Four hundred children scheduled for bilateral tube insertion were included in a randomized trial. The patients received one type of tube in the right ear and another type in the left ear. The incidence of tube extrusion and complications were monitored postoperatively every third month by an otolaryngologist.

RESULTS

Twenty-two children were excluded during surgery. Out of the studied 378 children the mean age was 35.3 months. 63.8% were boys. Short tubes extruded earlier than long tubes; hazard ratio (HR) 4.84 (95% CI 3.50-6.69, p < 0.001). Long Armstrong tubes were least prone to extrude. Silicone tubes resulted in significantly longer time to first infection in a VT ear, HR 1.68 (95% CI 1.03-2.76, p = 0.039). Donaldson tubes rendered the longest mean time to first infection (p = 0.025). Infections did not affect tube extrusion rates significantly (p = 0.879). No significant differences were found regarding tube occlusion, tube extraction or persistent perforation.

CONCLUSIONS

Long tubes are less prone to extrude early. Long Armstrong tubes have the least propensity to extrude early. Silicone tubes render significantly longer time to first infection. Donaldson tubes result in least infections. Infection does not affect extrusion rates significantly.

LEVEL OF EVIDENCE

1b.

Materials and Applications of Smart Diagnostic Contact Lens Systems

Contact lenses were originally developed for the purpose of vision correction, but they have recently been used for various purposes. Because contact lenses are minimally invasive, they are used in diagnostic and drug delivery applications. In particular, interest in using contact lenses for the purpose of diagnosing diseases by fusing contact lenses with information technology (IT), nanotechnology (NT), and biotechnology (BT) is increasing. These contact lens-based platforms are getting more attention as Google and Novartis develop contact lenses for diabetes diagnosis. Therefore, this chapter introduces materials that can be used for contact lens materials and diagnostic contact lenses, and discusses future prospects.

Development of a standard reference material containing 22 chlorinated hydrocarbon gases at 1 μmol/mol in nitrogen

A gas standard mixture containing 22 chlorinated hydrocarbons in high purity nitrogen was prepared using a two-step weighing method and a gasifying apparatus developed in-house. The concentration of each component was determined using a gas chromatograph with flame ionization detection (GC/FID). Linear regression analysis of every component was performed using the gas standard mixture with concentrations ranging from 1 to 10 μmol/mol, showing the complete gasification of volatile organic compound (VOCs) species in a selected cylinder. Repeatability was also examined to ensure the reliability of the preparation method. In addition, no significant difference was observed between domestic treated and imported treated cylinders, which were conducive to reduction of the cost of raw materials. Moreover, the results of stability testing at different pressures and long-term stability tests indicated that the gas standard at 1 μmol/mol level with relative expanded uncertainties of 5% was stable above 2 MPa for a minimum of 12 months. Finally, a quantity comparison was conducted between the gas standard and a commercial gas standard from Scott Specialty Gases (now Air Liquide America Specialty Gases). The excellent agreement of every species suggested the favorable accuracy of our gas standard. Therefore, this reference material can be applied to routine observation of VOCs and for other purposes.

Influence of the material for preformed moulds on the polymerization temperature of resin materials for temporary FPDs

PURPOSE

Temperature increase of 5.5 ℃ can cause damage or necrosis of the pulp. Increasing temperature can be caused not only by mechanical factors, e.g. grinding, but also by exothermic polymerization reactions of resin materials. The aim of this study was to evaluate influences of the form material on the intrapulpal temperature during the polymerization of different self-curing resin materials for temporary restorations.

MATERIALS AND METHODS

30 provisonal bridges were made of 5 resin materials: Prevision Temp (Pre), Protemp 4 (Pro), Luxatemp Star (Lux), Structure 3 (Str) and an experimental material (Exp). Moulds made of alginate (A) and of silicone (S) and vacuum formed moulds (V) were used to build 10 bridges each on a special experimental setup. The intrapulpal temperatures of three abutment teeth (a canine, a premolar, and a molar,) were measured during the polymerization every second under isothermal conditions. Comparisons of the maximum temperature (T_Max) and the time until the maximum temperature (t_TMax) were performed using ANOVA and Tukey Test.

RESULTS

Using alginate as the mould material resulted in a cooling effect for every resin material. Using the vacuum formed mould, T_Max increased significantly compared to alginate (P<.001) and silicone (P<.001). In groups Lux, Pro, and Pre, t_TMax increased when the vacuum formed moulds were used. In groups Exp and Str, there was no influence of the mould material on t_TMax.

CONCLUSION

All of the mould materials are suitable for clinical use if the intraoral application time does not exceed the manufacturer's instructions for the resin materials.

Application of Materials as Medical Devices with Localized Drug Delivery Capabilities for Enhanced Wound Repair

The plentiful assortment of natural and synthetic materials can be leveraged to accommodate diverse wound types, as well as different stages of the healing process. An ideal material is envisioned to promote tissue repair with minimal inconvenience for patients. Traditional materials employed in the clinical setting often invoke secondary complications, such as infection, pain, foreign body reaction, and chronic inflammation. This review surveys the repertoire of surgical sutures, wound dressings, surgical glues, orthopedic fixation devices and bone fillers with drug eluting capabilities. It highlights the various techniques developed to effectively incorporate drugs into the selected material or blend of materials for both soft and hard tissue repair. The mechanical and chemical attributes of the resultant materials are also discussed, along with their biological outcomes in vitro and/or in vivo. Perspectives and challenges regarding future research endeavors are also delineated for next-generation wound repair materials.

The impacts of different embolization techniques on splenic artery embolization for blunt splenic injury: a systematic review and meta-analysis

BACKGROUND

Splenic artery embolization (SAE) has been an effective adjunct to the Non-operative management (NOM) for blunt splenic injury (BSI). However, the optimal embolization techniques are still inconclusive. To further understand the roles of different embolization locations and embolic materials in SAE, we conducted this system review and meta-analyses.

METHODS

Clinical studies related to SAE for adult patients were researched in electronic databases, included PubMed, Embase, ScienceDirect and Google Scholar Search (between October 1991 and March 2013), and relevant information was extracted. To eliminate the heterogeneity, a sensitivity analysis was conducted on two reduced study sets. Then, the pooled outcomes were compared and the quality assessments were performed using Newcastle-Ottawa Scale (NOS). The SAE success rate, incidences of life-threatening complications of different embolization techniques were compared by χ² test in 1st study set. Associations between different embolization techniques and clinical outcomes were evaluated by fixed-effects model in 2nd study set.

RESULTS

Twenty-three studies were included in 1st study set. And then, 13 of them were excluded, because lack of the necessary details of SAE. The remaining 10 studies comprised 2nd study set, and quality assessments were performed using NOS. In 1st set, the primary success rate is 90.1% and the incidence of life-threatening complications is 20.4%, though the cases which required surgical intervention are very few (6.4%). For different embolization locations, there was no obvious association between primary success rate and embolization location in both 1st and 2nd study sets (P > 0.05). But in 2nd study set, it indicated that proximal embolization reduced severe complications and complications needed surgical management. As for the embolic materials, the success rate between coil and gelfoam is not significant. However, coil is associated with a lower risk of life-threatening complications, as well as less complications requiring surgical management.

CONCLUSIONS

Different embolization techniques affect the clinical outcomes of SAE. The proximal embolization is the best option due to the less life-threatening complications. For commonly embolic material, coil is superior to gelfoam for fewer severe complications and less further surgery management.

Clinical and epidemiological differences between implant-associated and implant-free orthopaedic infections

PURPOSE

Although there have been many publications regarding the risk factors for implant-associated orthopaedic infections, none have investigated how clinical presentations and epidemiology may differ between infections with and without osteosynthetic material.

METHODS

We pooled clinical data from several databases of adult patients with orthopaedic infections hospitalized at Geneva University Hospitals from January 2004 to December 2014.

RESULTS

Among 2740 episodes of orthopaedic infections, 76% were implant-free osteoarticular or soft tissue infections. Among the 665 (24% of the total episodes) infections that involved osteosynthetic material, 319 (49%) were total joint arthroplasties, 143 single plates, and 50 single nails. The remainders were mixed implant infections, pins, wires, screws, cerclages or spondylodeses. The implant-associated, compared to the implant-free, infections were significantly more frequently associated with female sex, older age, bacteraemia and skin commensal infections, e.g. coagulase-negative staphylococci, corynebacteria or propionibacteria. In contrast, implant-associated infections were significantly less frequently associated with immune suppression, abscess formation, infections due to Staphylococcus aureus or streptococci, polymicrobial pathogens and foot infections. The serum CRP levels at admission were similar (median 82 vs. 75 mg/L).

CONCLUSIONS

Compared to implant-free infections, implant-associated orthopaedic infections are more likely monomicrobial, bacteraemic and due to skin commensals. They involve more often female and older patients, but are less often associated with immune suppression, abscess formation and foot infections.

A randomized study of four different types of tympanostomy ventilation tubes - One-year follow-up

OBJECTIVE

To compare four different types of tympanostomy ventilation tubes (VT); long-shaft and short-shaft silicone tubes and long-shaft and short-shaft fluoroplastic tubes, regarding time to extrusion and events of otorrhea.

METHODS

A prospective randomized controlled trial in children with bilateral recurrent acute otitis media or secretory otitis media; four hundred children were randomized to receive one type of VT in the right ear and another type in the left ear. Postoperatively the children were assessed every third month by an otolaryngologist to monitor the incidence of otorrhea and tube extrusion.

RESULTS

Out of the 400 children, 22 were excluded during surgery. Mean age was 35.3 months. A majority (63.8%) were boys. Forty-eight children were lost to follow up during the first year. Significantly more short-shaft VTs were extruded after 12 months compared to long-shaft VTs, regardless of material. Significantly higher incidence of otorrhea was found in the fluoroplastic VT ears compared to the silicone ones, regardless of length of tube.

CONCLUSION

Long-shaft VTs last longer in the eardrum during the first year of treatment. Silicone tubes render a reduced risk of otorrhea during the first year of treatment.

Computational fluid dynamics of cerebral aneurysm coiling using high-resolution and high-energy synchrotron X-ray microtomography: comparison with the homogeneous porous medium approach

BACKGROUND

Computational modeling of intracranial aneurysms provides insights into the influence of hemodynamics on aneurysm growth, rupture, and treatment outcome. Standard modeling of coiled aneurysms simplifies the complex geometry of the coil mass into a homogeneous porous medium that fills the aneurysmal sac. We compare hemodynamics of coiled aneurysms modeled from high-resolution imaging with those from the same aneurysms modeled following the standard technique, in an effort to characterize sources of error from the simplified model.

MATERIALS

Physical models of two unruptured aneurysms were created using three-dimensional printing. The models were treated with coil embolization using the same coils as those used in actual patient treatment and then scanned by synchrotron X-ray microtomography to obtain high-resolution imaging of the coil mass. Computational modeling of each aneurysm was performed using patient-specific boundary conditions. The coils were modeled using the simplified porous medium or by incorporating the X-ray imaged coil surface, and the differences in hemodynamic variables were assessed.

RESULTS

X-ray microtomographic imaging of coils and incorporation into computational models were successful for both aneurysms. Porous medium calculations of coiled aneurysm hemodynamics overestimated intra-aneurysmal flow, underestimated oscillatory shear index and viscous dissipation, and over- or underpredicted wall shear stress (WSS) and WSS gradient compared with X-ray-based coiled computational fluid dynamics models.

CONCLUSIONS

Computational modeling of coiled intracranial aneurysms using the porous medium approach may inaccurately estimate key hemodynamic variables compared with models incorporating high-resolution synchrotron X-ray microtomographic imaging of complex aneurysm coil geometry.

Preparation of Internal Quality Control Material for Lymphocyte Subset Analysis

Lymphocyte subset analysis is widely used in clinical laboratories, and more than two levels of daily QC materials are required for reliable results. Commercially available, expensive QC materials have short shelf lives and may not be suitable in resource-poor settings. We compared different methods for preparing homemade QC material, including fixation with 1%, 2%, or 4% paraformaldehyde (PFA); freezing with 10% dimethylsulfoxide (DMSO), 0.1% bovine serum albumin-phosphate buffered saline, or after ethanolic dehydration; and using cryopreservation temperatures of -20℃, -80℃, or -196℃. We found an optimal experimental condition, which is 'fixation with 4% PFA, freezing with 10% DMSO, and storage at 80℃'. To evaluate long-term stability of QC materials prepared in this optimal condition, two levels of QC materials (QM1 and QM2) were thawed after 30, 33, 35, 37, 60, 62, 64, and 67 days of cryopreservation. Lymphocyte subset was analyzed with BD Multitest IMK kit (BD Biosciences, USA). QM1 and QM2 were stable after 1-2 months of cryopreservation (CV <3% for CD3, CD4, and CD8 and 5-7% for CD16/56 and CD19). We propose this method as an alternative cost-effective protocol for preparing homemade internal QC materials for lymphocyte subset analysis in resource-poor settings.

Effects of material properties and object orientation on precision grip kinematics

Successfully picking up and handling objects requires taking into account their physical properties (e.g., material) and position relative to the body. Such features are often inferred by sight, but it remains unclear to what extent observers vary their actions depending on the perceived properties. To investigate this, we asked participants to grasp, lift and carry cylinders to a goal location with a precision grip. The cylinders were made of four different materials (Styrofoam, wood, brass and an additional brass cylinder covered with Vaseline) and were presented at six different orientations with respect to the participant (0°, 30°, 60°, 90°, 120°, 150°). Analysis of their grasping kinematics revealed differences in timing and spatial modulation at all stages of the movement that depended on both material and orientation. Object orientation affected the spatial configuration of index finger and thumb during the grasp, but also the timing of handling and transport duration. Material affected the choice of local grasp points and the duration of the movement from the first visual input until release of the object. We find that conditions that make grasping more difficult (orientation with the base pointing toward the participant, high weight and low surface friction) lead to longer durations of individual movement segments and a more careful placement of the fingers on the object.

Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: a single-center series with special emphasis on covered cortical branches and perforating arteries

BACKGROUND

Data regarding anatomic and clinical results of flow diversion treatment in complex bifurcation aneurysms of the anterior circulation are scarce.

OBJECTIVE

To present our results of treatment of these lesions with special emphasis on the fate of 'jailed' cortical branches and perforating arteries.

METHODS

Seventeen patients were treated with flow diverters (FDs) for 18 aneurysms of the middle cerebral artery bifurcation (n=13) and the anterior communicating artery complex (n=5). Nineteen cortical branches were covered. A single FD was used in all patients.

RESULTS

At latest follow-up (mean 7.9 months; range 3-36; median 4.0) 2/19 (10.5%) of the covered branches were occluded, 9/19 (47.4%) showed a decreased caliber and the remaining branches were unchanged. All branch modifications were clinically asymptomatic. Mortality and permanent morbidity were 0%. Symptomatic ischemic events in perforator territories occurred in three patients (17.6%), which were reversible in all of them within 24 h. Follow-up MRI disclosed asymptomatic lacunar defects corresponding to covered perforating artery territories in five patients (29.4%). Altogether, perforator lesions-symptomatic and asymptomatic-occurred in 7/17 patients (41.2%). 33.3% of the aneurysms were occluded at latest follow-up; decreased diameters were seen in the other 66.7%.

CONCLUSIONS

Flow diversion of bifurcation aneurysms is feasible with low rates of permanent morbidity and mortality. Caliber reduction and asymptomatic occlusion of covered cortical branches seems to be common, yet ischemic complications are rather linked to perforator occlusions. Our results on aneurysm occlusion rates are preliminary and longer follow-up periods are warranted.

[Posterior capsule opacification]

Posterior capsule opacification (PCO) is the most common complication after cataract surgery, with an incidence of 30%. It tends to be considered a normal event in the natural history of cataract surgery. Better understanding of its pathophysiology and advancement of intraocular lens material and design along with the improvement of phacoemulsification technique have contributed to decrease the incidence of PCO. Although treatment by Nd: YAG laser posterior capsulotomy is quick and non-invasive, the opening of the posterior capsule may be associated with numerous complications. Prevention remains the best measure for controlling this pathology.

Unrealistic statistics: how average constitutive coefficients can produce non-physical results

The coefficients of constitutive models are frequently averaged in order to concisely summarize the complex, nonlinear, material properties of biomedical materials. However, when dealing with nonlinear systems, average inputs (e.g. average constitutive coefficients) often fail to generate average behavior. This raises an important issue because average nonlinear constitutive coefficients of biomedical materials are commonly reported in the literature. This paper provides examples which demonstrate that average constitutive coefficients applied to nonlinear constitutive laws in the field of biomedical material characterization can fail to produce average stress-strain responses and in some cases produce non-physical responses. Results are presented from a literature survey which indicates that approximately 90% of tissue measurement studies that employ a nonlinear constitutive model report average nonlinear constitutive coefficients. We suggest that reviewers and editors of future measurement studies discourage the reporting of average nonlinear constitutive coefficients. Reporting of individual coefficient sets for each test sample should be considered and discussed as designation for a "best practice" in the field of biomedical material characterization.