Evidence for multiple potential drivers of increased phosphorus in high-elevation lakes

Total phosphorus (TP) concentrations have increased in many remote mountain waterbodies across the western United States, and reports of algal blooms in these systems have increased in frequency. Explanations for observed TP increases are uncertain, and typical landscape drivers, such as agricultural/urban runoff, are implausible. We investigated multiple atmospheric and terrestrial-P loading mechanisms to explain the observed decadal increase in TP, including a novel hypothesis that warming soils may lead to elevated P fluxes to receiving water bodies. Using northern Utah mountains ranges as a case study, we measured prospective inputs of total and bioavailable P via dust deposition. Terrestrial loading was evaluated through soil leaching experiments designed to simulate soil acidification and recovery, as well as observed decadal increases in soil temperatures and extended growing season. In the Uinta Mountains, dust-P flux appears to be one of the most plausible mechanisms for P increases where we estimated bioavailable dust-P loading ranged from 1.6 to 23.1 mg P m^-2 yr^-1. However, our results revealed that an increase of soil pH by 0.5 units could lead to a rise in leached P, ranging from 4.7 to 65 mg P m^-2. Rising temperatures also showed the potential to increase soil P leaching; Observed average historical (~ +3 °C) and future (+2 °C) increases in temperature led to a prospective increase in leached P from 2 to 264 mg SRP m^-2. While we found that pH shifts can mobilize significant amounts of P in some locations, we found no evidence of pH changes through time in the Uinta Mountains. However, summer soil temperatures increased at most locations. The mechanisms evaluated in this study can help explain the widespread observed increases in P across Western US lakes, but the mechanisms that dominate in any given region are likely to vary based on local to regional factors.

Challenges and solutions in adapting an AI-powered health management tool for South African

Background

Africa has the lowest density of healthcare workers in the world and artificial intelligence (AI) technology can assist doctors and patients to bridge that gap. This paper describes the 3 challenges we identified to adapt Ada, an AI-powered health management tool, to assist pregnant women and mothers in South Africa (SA).

Challenges and solutions

Localization

Maternal and child health challenges in SA differ from those in the West. We adapted Ada's knowledge base to account for regional differences in incidence and disease presentation. We optimized 51 maternal and pediatric health conditions.

Readability

An improved readability leads to better understanding of medical content. We calculated the readability score of Ada's consumer-facing medical content using the Automated Readability Index and deemed it too high (grade 11.0±1.8, range=5.8-17.5). Using Content Design London's Readability Guidelines, we reduced the readability score of Ada's content to below grade 8 (7.4±0.8, range=4.6-10.2) while maintaining medical accuracy.

Different approaches to AI

The majority of medical research is conducted in high-income countries and tends to recruit people with high literacy levels. This means the differences in underrepresented populations and low-income countries are not captured in medical research. When this data is applied to technology and AI, it can lead to bias. To reduce this bias, we use a white-box approach. This allows us to deliver solutions to meet the needs of a specific population. Using the expertise of medical doctors with clinical experience in low-income areas, we curated a medical knowledge base that was specific to our target population.

Conclusions

AI solutions can only improve health outcomes in low-income countries if they are designed and adapted with the needs of the local population in mind. By partnering with local health departments, AI health companies can assist doctors and patients to reduce the burden on vulnerable healthcare systems.

Key messages

White-box AI-approach makes it possible to build AI solutions that capture the differences in underrepresented populations and low-income countries. By partnering with local health departments, AI health companies can assist patients and doctors in reducing the burden on vulnerable healthcare systems.

CaRdiac Arrest Survival Score (CRASS) - A tool to predict good neurological outcome after out-of-hospital cardiac arrest

AIM

The aim of this study was to develop a score to predict the outcome for patients brought to hospital following out-of-hospital cardiac arrest (OHCA).

METHODS

All patients recorded in the German Resuscitation Registry (GRR) who suffered OHCA 2010-2017, who had ROSC or ongoing CPR at hospital admission were included. The study population was divided into development (2010-2016: 7985) and validation dataset (2017: 1806). Binary logistic regression analysis was used to derive the score. The probability of hospital discharge with good neurological outcome was defined as 1/(1 + e^-X), where X is the weighted sum of independent variables.

RESULTS

The following variables were found to have a significant positive (+) or negative (-) impact: age 61-70 years (-0·5), 71-80 (-0·9), 81-90 (-1·3) and > = 91 (-2·3); initial PEA (-0·9) and asystole (-1·4); presumable trauma (-1·1); mechanical CPR (-0·3); application of adrenalin > 0 - < 2 mg (-1·1), 2 - <4 mg (-1·6), 4 - < 6 mg (-2·1), 6 - < 8 mg (-2·5) and > = 8 mg (-2·8); pre emergency status without previous disease (+0·5) or minor disease (+0·2); location at nursing home (-0·6), working place/school (+0·7), doctor's office (+0·7) and public place (+0·3); application of amiodarone (+0·4); hospital admission with ongoing CPR (-1·9) or normotension (+0·4); witnessed arrest (+0·6); time from collapse until start CPR 2 - < 10 min (-0·3) and > = 10 min (-0·5); duration of CPR <5 min (+0·6). The AUC in the development dataset was 0·88 (95% CI 0·87-0·89) and in the validation dataset 0·88 (95% CI 0·86-0·90).

CONCLUSION

The CaRdiac Arrest Survival Score (CRASS) represents a tool for calculating the probability of survival with good neurological function for patients brought to hospital following OHCA.

Architecture of Anoteropora latirostris (Bryozoa, Cheilostomata) and implications for their biomineralization

Cheilostome Bryozoa Anoteropora latirostris, a colonial marine invertebrate, constructs its skeleton from calcite and aragonite. This study presents firstly correlated multi-scale electron microscopy, micro-computed tomography, electron backscatter diffraction and NanoSIMS mapping. We show that all primary, coarse-grained platy calcitic lateral walls are covered by fine-grained fibrous aragonite. Vertical lateral walls separating autozooid chambers have aragonite only on their distal side. This type of asymmetric mineralization of lateral walls results from the vertical arrangement of the zooids at the growth margins of the colony and represents a type of biomineralization previously unknown in cheilostome bryozoans. NanoSIMS mapping across the aragonite-calcite interface indicates an organic layer between both mineral phases, likely representing an organic template for biomineralization of aragonite on the calcite layer. Analysis of crystallographic orientations show a moderately strong crystallographic preferred orientation (CPO) for calcite (7.4 times random orientation) and an overall weaker CPO for aragonite (2.4 times random orientation) with a high degree of twinning (45%) of the aragonite grains. The calculated Young's modulus for the CPO map shows a weak mechanical direction perpendicular to the colony's upper surface facilitating this organism's strategy of clonal reproduction by fragmentation along the vertical zooid walls.

An automatable platform for genotoxicity testing of nanomaterials based on the fluorometric γ-H2AX assay reveals no genotoxicity of properly surface-shielded cadmium-based quantum dots

The large number of nanomaterial-based applications emerging in the materials and life sciences and the foreseeable increasing use of these materials require methods that evaluate and characterize the toxic potential of these nanomaterials to keep safety risks to people and environment as low as possible. As nanomaterial toxicity is influenced by a variety of parameters like size, shape, chemical composition, and surface chemistry, high throughput screening (HTS) platforms are recommended for assessing cytotoxicity. Such platforms are not yet available for genotoxicity testing. Here, we present first results obtained for application-relevant nanomaterials using an automatable genotoxicity platform that relies on the quantification of the phosphorylated histone H2AX (γ-H2AX) for detecting DNA double strand breaks (DSBs) and the automated microscope system AKLIDES® for measuring integral fluorescence intensities at different excitation wavelengths. This platform is used to test the genotoxic potential of 30 nm-sized citrate-stabilized gold nanoparticles (Au-NPs) as well as micellar encapsulated iron oxide nanoparticles (FeOx-NPs) and different cadmium (Cd)-based semiconductor quantum dots (QDs), thereby also searching for positive and negative controls as reference materials. In addition, the influence of the QD shell composition on the genotoxic potential of these Cd-based QDs was studied, using CdSe cores as well as CdSe/CdS core/shell and CdSe/CdS/ZnS core/shell/shell QDs. Our results clearly revealed the genotoxicity of the Au-NPs and its absence in the FeOx-NPs. The genotoxicity of the Cd-QDs correlates with the shielding of their Cd-containing core, with the core/shell/shell architecture preventing genotoxicity risks. The fact that none of these nanomaterials showed cytotoxicity at the chosen particle concentrations in a conventional cell viability assay underlines the importance of genotoxicity studies to assess the hazardous potential of nanomaterials.

An Exploratory Study of People's Perceptions and Experiences of Wellbeing

This paper describes an exploratory study aimed at understanding peoples perceptions and experiences of wellbeing. As health and wellbeing are considered by world and national health authorities to be closely related, occupational therapists along with other health workers need to know more about wellbeing, particularly from the perspective of ‘the people’.

Using a questionnaire, seven cluster samples of 20 people, giving a total of 140 participants, were asked to define their concept of wellbeing, how it felt to them and how often they experienced the feeling. Data were also collected about nationality, marital status, employment, income, religion and levels of education because these have been identified as affecting wellbeing. In this study, wellbeing was described as happiness, peace, mind and body health and self-esteem, and was strongly associated with occupations as varied as work, relaxation and dressing up; relationships; and environments. No particular associations were found with any of the demographic data.

Navigating a Robotic Wheelchair in a Railway Station during Rush Hour

This paper describes the hardware design, control, and navigation system of and some preliminary experiments with the robotic wheelchair Mobility Aid for elderly and disabled people (MAid). MAid’s general task is to transport people with severely impaired motion skills. The authors did not set out to reinvent and redevelop the set of standard skills of so-called intelligent wheelchairs, such as Follow Wall, FollowCorridor, PassDoorway, which are commonly described in the literature. These maneuvers require motion control skills that disabled people, in spite of their disabilities, are eager to learn and quite good at using. Instead, this work focused on generalizing the approach to fine motion control by considering those maneuvers identified as very burdensome due to their duration and required concentration. One of these functions is deliberative locomotion in rapidly changing, large-scale environments, such as shopping malls, entry halls of theaters, and concourses of airports or railway stations, where tens or hundreds of people and objects move around. MAid’s performance was tested in the central station of Ulm during rush hour and in the exhibition halls of the Hannover Messe ’98, the largest industrial fair in the world. Altogether, MAid has survived more than 36 h of testing in public, crowded environments with heavy passenger traffic.

Effect of propofol on hypoxia re-oxygenation induced neuronal cell damage in vitro*

Propofol may protect neuronal cells from hypoxia re-oxygenation injury, possibly via an antioxidant actions under hypoxic conditions. This study investigated the molecular effects of propofol on hypoxia-induced cell damage using a neuronal cell line. Cultured human IMR-32 cells were exposed to propofol (30 μm) and biochemical and molecular approaches were used to assess cellular effects. Propofol significantly reduced hypoxia-mediated increases in lactate dehydrogenase, a marker of cell damage (mean (SD) for normoxia: 0.39 (0.07) a.u.; hypoxia: 0.78 (0.21) a.u.; hypoxia+propofol: 0.44 (0.17) a.u.; normoxia vs hypoxia, p<0.05; hypoxia vs hypoxia+propofol, p<0.05), reactive oxygen species and hydrogen peroxide. Propofol also diminished the morphological signs of cell damage. Increased amounts of catalase, which degrades hydrogen peroxide, were detected under hypoxic conditions. Propofol decreased the amount of catalase produced, but increased its enzymatic activity. Propofol protects neuronal cells from hypoxia re-oxygenation injury, possibly via a combined direct antioxidant effect along with induced cellular antioxidant mechanisms.

The effect of real-time gait retraining on hip kinematics, pain and function in subjects with patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome (PFPS) is the most common overuse injury in runners. Recent research suggests that hip mechanics play a role in the development of this syndrome. Currently, there are no treatments that directly address the atypical mechanics associated with this injury.

OBJECTIVE

The purpose of this study was to determine whether gait retraining using real-time feedback improves hip mechanics and reduces pain in subjects with PFPS.

METHODS

Ten runners with PFPS participated in this study. Real-time kinematic feedback of hip adduction (HADD) during stance was provided to the subjects as they ran on a treadmill. Subjects completed a total of eight training sessions. Feedback was gradually removed over the last four sessions. Variables of interest included peak HADD, hip internal rotation (HIR), contralateral pelvic drop, as well as pain on a verbal analogue scale and the lower-extremity function index. We also assessed HADD, HIR and contralateral pelvic drop during a single leg squat. Comparisons of variables of interest were made between the initial, final and 1-month follow-up visit.

RESULTS

Following the gait retraining, there was a significant reduction in HADD and contralateral pelvic drop while running. Although not statistically significant, HIR decreased by 23% following gait retraining. The 18% reduction in HADD during a single leg squat was very close to significant. There were also significant improvements in pain and function. Subjects were able to maintain their improvements in running mechanics, pain and function at a 1-month follow-up. An unexpected benefit of the retraining was an 18% and 20% reduction in instantaneous and average vertical load rates, respectively.

CONCLUSIONS

Gait retraining in individuals with PFPS resulted in a significant improvement of hip mechanics that was associated with a reduction in pain and improvements in function. These results suggest that interventions for PFPS should focus on addressing the underlying mechanics associated with this injury. The reduction in vertical load rates may be protective for the knee and reduce the risk for other running-related injuries.

Correlation and agreement between the bispectral index vs. state entropy during hypothermic cardio-pulmonary bypass

BACKGROUND

The bispectral index (BIS) and spectral entropy enable monitoring the depth of anaesthesia. Mild hypothermia has been shown to affect the ability of electroencephalography monitors to reflect the anaesthetic drug effect. The purpose of this study was to investigate the effect of hypothermia during a cardio-pulmonary bypass on the correlation and agreement between the BIS and entropy variables compared with normothermic conditions.

METHODS

This prospective clinical study included coronary artery bypass grafting patients (n=25) evaluating correlation and agreement (Bland-Altman analysis) between the BIS and both spectral and response entropy during a hypothermic cardio-pulmonary bypass (31-34 degrees C) compared with nomothermic conditions (34-37.5 degrees C). Anaesthesia was maintained with propofol and sufentanil and adjusted clinically, while the anaesthetist was blinded to the monitors.

RESULTS

The BIS and entropy values decreased during cooling (P<0.05), but the decrease was more pronounced for entropy variables compared with BIS (P<0.05). The correlation coefficients (bias+/-SD; percentage error) between the BIS vs. spectral state entropy and response entropy were r(2)=0.56 (1+/-11; 42%) and r(2)=0.58 (-2+/-11; 43%) under normothermic conditions, and r(2)=0.17 (10+/-12; 77%) and r(2)=0.18 (9+/-11; 68%) under hypothermic conditions, respectively. Bias was significantly increased under hypothermic conditions (P<0.001 vs. normothermia).

CONCLUSION

Acceptable agreement was observed between the BIS and entropy variables under normothermic but not under hypothermic conditions. The BIS and entropy variables may therefore not be interchangeable during a hypothermic cardio-pulmonary bypass.

A comparison of the i-gel with the LMA-Unique in non-paralysed anaesthetised adult patients

SUMMARY

This study assessed two disposable devices; the newly developed supraglottic airway device i-gel and the LMA-Unique in routine clinical practice. Eighty patients (ASA 1-3) undergoing minor routine gynaecologic surgery were randomly allocated to have an i-gel (n = 40) or LMA-Unique (n = 40) inserted. Oxygen saturation, end-tidal carbon dioxide, tidal volume and peak airway pressure were recorded, as well as time of insertion, airway leak pressure, postoperative sore-throat, dysphonia and dysphagia for each device. Time of insertion was comparable with the i-gel and LMA-Unique. There was no failure in the i-gel group and one failure in the LMA-Unique group. Ventilation and oxygenation were similar between devices. Mean airway pressure was comparable with both devices, whereas airway leak pressure was significantly higher (p < 0.0001) in the i-gel group (mean 29 cmH(2)O, range 24-40) compared with the LMA-Unique group (mean 18 cmH(2)O, range 6-30). Fibreoptic score of the position of the devices was significantly better in the i-gel group. Post-operative sore-throat and dysphagia were comparable with both devices. Both devices appeared to be simple alternatives to secure the airway. Significantly higher airway leak pressure suggests that the i-gel may be advantageous in this respect.

Influence of different remifentanil concentrations on the performance of the surgical stress index to detect a standardized painful stimulus during sevoflurane anaesthesia

BACKGROUND

Although measurement of cerebral hypnotic drug effect and muscle relaxation is common clinical routine during anaesthesia, a reliable measurement of the neurophysiological effects evoked by a painful stimulus is still missing. Recently, the surgical stress index (SSI) has been introduced as a surrogate measure of 'nociception'. The present study aimed to examine the influence of increasing remifentanil concentrations on the ability of SSI to detect a standardized painful stimulus during sevoflurane anaesthesia.

METHODS

Twenty-four patients received incremental or decremental doses of 0, 2, and 4 ng ml(-1) remifentanil effect-site concentration (Ce(remi)) during 0.7 MAC sevoflurane. Painful tetanic stimulation was applied at least 5 min after changing Ce(remi). SSI, heart rate (HR), response entropy (RE), state entropy (SE), RE-SE difference, and bispectral index (BIS) were obtained in each patient before and after stimulation. Further prediction of an author-defined response to painful stimulus was analysed.

RESULTS

SSI and BIS, but not HR, SE, RE, or RE-SE difference were significantly altered after stimulation. Change in SSI (Delta SSI) was significantly dependent on Ce(remi), as Delta SSI was [median (inter-quartile range)] 20 (15-31), 10 (1-19), and 3 (1-10) at 0, 2, and 4 ng ml(-1) Ce(remi). In 10 out of 63 cases, SSI detected response to stimulation, not detected by another variable. SSI was unable to predict movement after stimulation as P(K) value is 0.59 (0.09).

CONCLUSIONS

The SSI response to tetanic stimulation was dependent on the remifentanil concentration.

Influence of anaesthesia resident training on the duration of three common surgical operations

We investigated the influence of resident training on anaesthesia workflow of three standard procedures--laparoscopic cholecystectomy, diagnostic gynaecological laparoscopy and transurethral prostate gland resection (TURP)--comparing 259 non-emergency resident vs 341 consultant cases from 20 German hospitals. Each hospital provided 10 random cases for each procedure, yielding 600 cases for analysis. Standard time intervals as documented in the hospital information system were: 'Case Time' (the time from the start of anaesthesia induction to discharge of the patient to the recovery area) and 'Anaesthesia Control Time' (which was the Case Time minus the time from the start of surgery to the end of surgical closure). Case Time was significantly shorter for consultants in all three procedures (p < 0.05, analysis of variance) and Anaesthesia Control Time shorter for consultants only in gynaecological laparoscopy and TURP. Patient comorbidity, patient age and geographical location of the hospital were not influential factors in the analysis of variance. We conclude that resident training significantly increases duration of elective operative times.

[The gynecological TURP syndrome. Severe hyponatremia and pulmonary edema during hysteroscopy]

Fluid overload and dilutional hyponatremia are rare but typical complications of endoscopic transurethral resection of the prostate gland (TURP syndrome). Less commonly, this complication caused by excessive absorption of hypotonic, electrolyte-free non-conductive distention solution, may also occur during endoscopic surgery of the uterus, e.g. operative hysteroscopy. A case report is presented of a 44-year-old woman scheduled for operative hysteroscopy for intracavital myoma under general anaesthesia, suffering from severe absorption syndrome leading to hyponatremia of 106 mEq/l and pulmonary edema necessitating subsequent admission to ICU. Anatomical and physiological as well as technical aspects of this syndrome are discussed. Recommendations for anesthesiology management are offered and a possible treatment of acute hyponatremia is discussed.