bluuebunny/crossref_metadata_2025 huggingface dataset:
Tacrolimus Exposure Prediction Using Machine Learning
Authors: Woillard Jean‐Baptiste , Labriffe Marc , Debord Jean , Marquet Pierre
Published: November 2020

The aim of this work is to estimate the area‐under the blood concentration curve of tacrolimus (TAC) following b.i.d. or q.d. dosing in organ transplant patients, using Xgboost machine learning (ML) models. A total of 4,997 and 1,452 TAC interdose area under the curves (AUCs) from patients on b.i.d. and q.d. TAC, sent to our Immunosuppressant Bayesian Dose Adjustment expert system (www.pharmaco.chu‐limoges.fr/) for AUC estimation and dose recommendation based on TAC concentrations measured at least at 3 sampling times (predose, ~ 1 and 3 hours after dosing) were used to develop 4 ML models based on 2 or 3 concentrations. For each model, data splitting was performed to obtain a training set (75%) and a test set (25%). The Xgboost models in the training set with the lowest root mean square error (RMSE) in a 10‐fold cross‐validation experiment were evaluated in the test set and in 6 independent full‐pharmacokinetic (PK) datasets from renal, liver, and heart transplant patients. ML models based on two or three concentrations, differences between these concentrations, relative deviations from theoretical times of sampling, and four covariates (dose, type of transplantation, age, and time between transplantation and sampling) yielded excellent AUC estimation performance in the test datasets (relative bias < 5% and relative RMSE < 10%) and better performance than maximum a posteriori Bayesian estimation in the six independent full‐PK datasets. The Xgboost ML models described allow accurate estimation of TAC interdose AUC and can be used for routine TAC exposure estimation and dose adjustment. They will soon be implemented in a dedicated web interface.
Performance and Sustainability Tradeoffs of Oxidized Carbon Nanotubes as a Cathodic Material in Lithium‐Oxygen Batteries
Authors: Falinski Mark M. , Albalghiti Eva M. , Backhaus Andreas , Zimmerman Julie B.
Published: November 2020

Climate change mitigation efforts will require a portfolio of solutions, including improvements to energy storage technologies in electric vehicles and renewable energy sources, such as the high‐energy‐density lithium‐oxygen battery (LOB). However, if LOB technology will contribute to addressing climate change, improvements to LOB performance must not come at the cost of disproportionate increases in global warming potential (GWP) or cumulative energy demand (CED) over their lifecycle. Here, oxygen‐functionalized multi‐walled carbon nanotube (O‐MWCNT) cathodes were produced and assessed for their initial discharge capacities and cyclability. Contrary to previous findings, the discharge capacity of O‐MWCNT cathodes increased with the ratio of carbonyl/carboxyl moieties, outperforming pristine MWCNTs. However, increased oxygen concentrations decreased LOB cyclability, while high‐temperature annealing increased both discharge capacity and cyclability. Improved performance resulting from MWCNT post‐processing came at the cost of increased GWP and CED, which in some cases was disproportionately higher than the level of improved performance. Based on the findings presented here, there is a need to simultaneously advance research in improving LOB performance while minimizing or mitigating the environmental impacts of LOB production.
In Situ Classification of Cell Types in Human Kidney Tissue Using 3D Nuclear Staining
Authors: Woloshuk Andre , Khochare Suraj , Almulhim Aljohara F. , McNutt Andrew T. , Dean Dawson , Barwinska Daria , Ferkowicz Michael J. , Eadon Michael T. , Kelly Katherine J. , Dunn Kenneth W. , Hasan Mohammad A. , El‐Achkar Tarek M. , Winfree Seth
Published: November 2020

To understand the physiology and pathology of disease, capturing the heterogeneity of cell types within their tissue environment is fundamental. In such an endeavor, the human kidney presents a formidable challenge because its complex organizational structure is tightly linked to key physiological functions. Advances in imaging‐based cell classification may be limited by the need to incorporate specific markers that can link classification to function. Multiplex imaging can mitigate these limitations, but requires cumulative incorporation of markers, which may lead to tissue exhaustion. Furthermore, the application of such strategies in large scale 3‐dimensional (3D) imaging is challenging. Here, we propose that 3D nuclear signatures from a DNA stain, DAPI, which could be incorporated in most experimental imaging, can be used for classifying cells in intact human kidney tissue. We developed an unsupervised approach that uses 3D tissue cytometry to generate a large training dataset of nuclei images (NephNuc), where each nucleus is associated with a cell type label. We then devised various supervised machine learning approaches for kidney cell classification and demonstrated that a deep learning approach outperforms classical machine learning or shape‐based classifiers. Specifically, a custom 3D convolutional neural network (NephNet3D) trained on nuclei image volumes achieved a balanced accuracy of 80.26%. Importantly, integrating NephNet3D classification with tissue cytometry allowed in situ visualization of cell type classifications in kidney tissue. In conclusion, we present a tissue cytometry and deep learning approach for in situ classification of cell types in human kidney tissue using only a DNA stain. This methodology is generalizable to other tissues and has potential advantages on tissue economy and non‐exhaustive classification of different cell types.
Review of registered clinical trials for the treatment of COVID‐19
Authors: Babaei Fatemeh , Mirzababaei Mohammadreza , Nassiri‐Asl Marjan , Hosseinzadeh Hossein
Published: November 2020

Coronavirus disease 2019 (COVID‐19) is a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). The disease was first reported in December 2019 in Wuhan, China, but now more than 200 countries have been affected and the coronavirus pandemic is still ongoing. The severity of COVID‐19 symptoms can range from mild to severe. FDA approved remdesivir as a treatment of COVID‐19 so far. Various clinical trials are underway to find an effective method to treat patients with COVID‐19. This review aimed at summarizing 219 registered clinical trials in the ClinicalTrials.gov database with possible mechanisms, and novel findings of them, and other recent publications related to COVID‐19. According to our analyses, various treatment approaches and drugs are being investigated to find an effective drug to cure COVID‐19 and among all strategies, three important mechanisms are suggested to be important against COVID‐19 including antiviral, anti‐inflammatory, and immunomodulatory properties. Our review can help future studies get on the way to finding an effective drug for COVID‐19 treatment by providing ideas for similar researches.
Integration of solar dryer with a hybrid system of gasifier‐solid oxide fuel cell/micro gas turbine: Energy, economy, and environmental analysis
Authors: Safari Sadegh , Ghasedi Amir Hossein , Ozgoli Hassan Ali
Published: November 2020

A novel approach is presented to reduce the moisture content of biomass by employing a solar dryer. The impact of decreasing moisture contents on the key parameters of the system is investigated. Also, the effect of air mass flux on drying rate of biomass is evaluated and discussed considering three alternative air mass flux rates as well as two different time periods for drying and discharging biomass, namely 15 and 30 min. Results demonstrate that moisture reduction improves the output power and efficiency of the system from 265 kW and 30% up to 295 kW and 57.6%, respectively; in other words, employing solar dryer leads to an improvement of electrical efficiency up to 27.6%. The best efficiency performance of system is achieved by the 15 min drain time and air mass flux of 0.011 kgm−2s−1, while the best power generation of the system will be obtained by the 30 min drain time and air mass flux of 0.011 kgm−2s−1. Furthermore, the levelized cost of electricity analysis exhibits 0.39 $/kWh at the best performance of the system. The environmental analysis shows that the designed power plant has the potential to drop up to 721 tons of CO2/year, which has yielded an environmental benefit of 17,304 $/year when compared to a coal‐fired power plant of the same capacity.
Applications of the RTgill-W1 Cell Line for Acute Whole-Effluent Toxicity Testing: In Vitro–In Vivo Correlation and Optimization of Exposure Conditions
Authors: Scott Justin , Belden Jason B. , Minghetti Matteo
Published: November 2020

The cell line RTgill-W1 was evaluated as an in vitro alternative model for acute fish whole-effluent toxicity (WET) testing. We determined the 50% effective concentration (EC50) that reduces the viability of RTgill-W1 cells for selected toxicants commonly found in effluent samples and correlated those values with the respective 50% lethal concentration (LC50) of freshwater (fathead minnow, Pimephales promelas) and marine (sheepshead minnow, Cyprinodon variegatus) fish species obtained from the literature. Excluding low water-soluble organics and the volatile sodium hypochlorite, significant correlations were measured for metal, metalloids, ammonia, and higher water-soluble organics between in vitro EC50 values and in vivo LC50 values for both species. Typically, toxicity studies with RTgill-W1 cells are conducted by adding salts to the exposure medium, which may affect the bioavailability of toxicants. Osmotic tolerance of RTgill-W1 cells was found between 150 and 450 mOsm/kg, which were set as the hypoosmotic and hyperosmotic limits. A subset of the toxicants were then reexamined in hypoosmotic and hyperosmotic media. Copper toxicity decreased in hyperosmotic medium, and nickel toxicity increased in hypoosmotic and hyperosmotic media. Linear alkylbenzene sulfonate toxicity was not affected by the medium osmolality. Overall, RTgill-W1 cells have shown potential for applications in measuring metal, metalloids, ammonia, and water-soluble organic chemicals in acute WET tests, as well as complementing current toxicity identification and reduction evaluation strategies. In the present study, RTgill-W1 cells have been established as a valid animal alternative for WET testing, and we show that through manipulation of medium osmotic ranges, sensitivity to nickel was enhanced. Environ Toxicol Chem 2021;40:1050–1061. © 2020 SETAC

Abstract

Utilizing RTgill-W1 cells as an in vitro animal alternative for acute whole-effluent toxicity testing. EC50 = median effective concentration; LAS = linear alkylbenzene sulfonate; LC50 = median lethal concentration; QAC = quaternary ammonium compound (74.5% benzyldimethyldodecylammonium chloride, 22.3% benzyldimethyltetradecylammonium chloride).
Public health insurance and the labor market: Evidence from China's Urban Resident Basic Medical Insurance
Authors: Si Wei
Published: November 2020

This study provides empirical evidence on the labor market effects of public health insurance using evidence from China. In 2007, China launched a national public health insurance program, Urban Resident Basic Medical Insurance (URBMI), targeting residents in urban areas who were not insured by employment‐based health insurance. Using panel data from the China Health and Nutrition Survey, I identify the impacts of the program based on its staggered implementation across cities. I find that URBMI did not have a significant average causal effect on labor force participation. However, it did increase employment mobility, as evidenced by the decrease in long‐term employment and expansion of fixed‐term contract jobs and self‐employment. After the program was implemented, job lock declined and job flexibility increased, especially among women, the less educated, and individuals with good health status. The results also suggest increased employment for unhealthy workers, indicating a direct health improvement effect.
Can we mitigate the effect of natural disasters on child health? Evidence from the Indian Ocean tsunami in Indonesia
Authors: Lépine Aurélia , Restuccio Maria , Strobl Eric
Published: November 2020

The 2004 Indian Ocean tsunami was an international natural disaster unlike any seen before, killing 166,561 people in Aceh province, Indonesia. It prompted an unprecedented humanitarian response and was a catalyst in ending almost 30 years of civil conflict in Aceh. Since the tsunami was followed by a multitude of events, we first conduct a systematic review to identify those events in Indonesia. We then use a synthetic control method to estimate the combination of those effects on child mortality indicators in Aceh for the 13 years that followed the disaster using data from 258,918 children born between 1990 and 2017. The results show a significant increase in under‐5 mortality only the year after the tsunami and no effect in the medium term. However, younger and older children were affected differently in the medium term. In fact, we show a decrease in child mortality among children aged 1–4 years. In contrast, we observe an increase in mortality among children under‐1 in 2009 and 2010. Overall, the resilience of Aceh province points to the importance of coordinated international disaster responses after natural disasters.
Adjunctive testing by cytology, p16/Ki‐67 dual‐stained cytology or HPV16/18 E6 oncoprotein for the management of HPV16/18 screen‐positive women
Authors: Torres‐Ibarra Leticia , Lorincz Attila T. , Wheeler Cosette M. , Cuzick Jack , Hernández‐López Rubí , Spiegelman Donna , León‐Maldonado Leith , Rivera‐Paredez Berenice , Méndez‐Hernández Pablo , Lazcano‐Ponce Eduardo , Salmerón Jorge
Published: November 2020

High‐risk human papillomavirus type 16/18 (HPV16/18) genotyping is unable to accurately discriminate nonprogressive infections from those that will progress to cervical cancer. Our study aimed to assesses if additional testing either with liquid‐based cytology (LBC) or the putative progression markers p16/Ki‐67 and HPV16/18 E6 oncoprotein (E6) can improve the efficiency of HPV16/18 genotyping for triaging high‐risk HPV (hrHPV)‐positive women through better cancer risk stratification. Women attending colposcopy after positive HPV16/18 genotyping results within the Forwarding Research for Improved Detection and Access for Cervical Cancer Screening and Triage (FRIDA) hrHPV‐based screening study in Tlaxcala, Mexico, underwent further testing with LBC, p16/Ki‐67 dual‐stained (DS) cytology and E6. We calculated measures of test performance for detecting histologically confirmed cervical intraepithelial neoplasia grade 2 or higher (CIN2+) and grade 3 or higher (CIN3+). A number of 475 (64.3%) of 739 HPV16/18‐positive women had complete results for all tests. Triage positivity rates were 14.1%, 18.5% and 24.4%, for LBC, E6 and DS, respectively. Compared with LBC, DS had higher sensitivity (24.4% vs 60.0%) although lower specificity (87.0% vs 79.3%) for CIN3+ (P < .001), whereas E6 had a sensitivity of 37.8% and a specificity of 83.5%. No invasive cancer was missed by DS or E6, but 75% were in normal cytology. DS test was associated with nearly 75% reduction of colposcopy referrals compared with the direct referral of all HPV16/18‐positive women, giving the least number of colposcopies (n = 4.3) per CIN3+ detected. We show that adjunctive testing of HPV16/18‐positive women with DS may greatly reduce unnecessary colposcopy referrals within HPV‐based screening employing HPV16/18 genotyping while retaining acceptable sensitivity for CIN2+ and CIN3+.
Effect of the immune responses induced by implants in a integrated three‐dimensional micro‐nano topography on osseointegration
Authors: Yang Yun , Zhang Ting , Jiang Mengyang , Yin Xiaojie , Luo Xiayan , Sun Huiqiang
Published: November 2020

In order to explore the abilities of an integrated three‐dimensional micro‐nano topography in immunomodulation and promoting bone formation, present study focuses on the titanium sheets used in the micro‐nano topography by treating them with the sandblasted, large‐grit and acid‐etched (SLA)and alkaline thermal reaction. Further, we characterized and obtained the surface morphology, roughness, and hydrophilicity of the titanium sheets. Moreover, we detected their in vitro cytocompatibility and cell proliferation as well. In addition, investigation was carried out for the immunomodulatory ability of the titanium sheets in a micro‐nano topography by observing the expression of M1 (classical activated macrophage) and M2 (alternatively activated macrophage) type marker factors, inflammatory factors, and morphological changes of RAW264.7 cells cultured on the titanium sheets in different topographies. Through cell migration experiments and coculture, we observed the effects of different titanium sheet immune environments on osteoblast migration, extracellular matrix mineralization, and osteoblast gene expression. These results showed that the micro‐nano topography constructed through SLA and alkaline thermal treatment improved the hydrophilicity and promoted the cell proliferation. Moreover, it promoted RAW264.7 cells to polarize as M2 phenotype, thereby leading to the anti‐inflammatory effect of local microenvironments. This facilitated osteoblasts to secrete bone morphogenetic protein‐2 (BMP2) and vascular endothelial growth factor. Nonetheless, these findings provided a theoretical basis for the molecular biological mechanism related to implants in a micro‐nano topography which promoted the osteointegration while offering a meaningful theoretical basis for the clinical treatment of such implants.
An insight on egg white: From most common functional food to biomaterial application
Authors: Dong Xuan , Zhang Yu‐Qing
Published: November 2020

Natural egg white tis widely used as an ingredient in nutritional foods and for food processing. Due to its characteristic foaming, emulsification, adhesion, and gelation, and its heat setting, biocompatibility, and low cost, research into the application and development of egg white in biomaterials, especially medical biomaterials, have been receiving attention. The composition and characteristics of egg white protein, and the physical mixing and chemically cross‐linking of egg white with other materials used to make degradable packaging films, bioceramics, bioplastics, biomimetic films, hydrogels, 3D scaffolds, bone regeneration, biopatterning, biosensors, and so forth, are reviewed in detail in this report. The novel egg white‐based biomaterials in various forms and applications could be constructed mostly through physical treatments such as ultrasonic wave, ultraviolet, laser and other radiation or high‐temperature calcination. Furthermore, the application and prospects for the use of egg white in biomaterials is also discussed.
Patterns of Load-to-Strength Ratios Along the Spine in a Population-Based Cohort to Evaluate the Contribution of Spinal Loading to Vertebral Fractures
Authors: Mokhtarzadeh Hossein , Anderson Dennis E , Allaire Brett T , Bouxsein Mary L
Published: November 2020

Vertebral fractures (VFx) are common among older adults. Epidemiological studies report high occurrence of VFx at mid-thoracic and thoracolumbar regions of the spine; however, reasons for this observation remain poorly understood. Prior reports of high ratios of spinal loading to vertebral strength in the thoracolumbar region suggest a possible biomechanical explanation. However, no studies have evaluated load-to-strength ratios (LSRs) throughout the spine for a large number of activities in a sizeable cohort. Thus, we performed a cross-sectional study in a sample of adult men and women from a population-based cohort to: 1) determine which activities cause the largest vertebral LSRs, and 2) examine patterns of LSRs along the spine for these high-load activities. We used subject-specific musculoskeletal models of the trunk to determine vertebral compressive loads for 109 activities in 250 individuals (aged 41 to 90 years, 50% women) from the Framingham Heart Study. Vertebral compressive strengths from T4 to L4 were calculated from computed tomography–based vertebral size and bone density measurements. We determined which activities caused maximum LSRs at each of these spinal levels. We identified nine activities that accounted for >95% of the maximum LSRs overall and at least 89.6% at each spinal level. The activity with the highest LSR varied by spinal level, and three distinct spinal regions could be identified by the activity producing maximum LSRs: lateral bending with a weight in one hand (upper thoracic), holding weights with elbows flexed (lower thoracic), and forward flexion with weight (lumbar). This study highlights the need to consider a range of lifting, holding, and non-symmetric activities when evaluating vertebral LSRs. Moreover, we identified key activities that produce higher loading in multiple regions of the spine. These results provide the first guidance on what activities to consider when evaluating vertebral load-to-strength ratios in future studies, including those examining dynamic motions and the biomechanics of VFx. © 2020 American Society for Bone and Mineral Research (ASBMR).
Shoulder movement complexity in the aging shoulder: A cross‐sectional analysis and reliability assessment
Authors: Overbeek Celeste L. , Geurkink Timon H. , de Groot Fleur A. , Klop Ilse , Nagels Jochem , Nelissen Rob G. H. H. , de Groot Jurriaan H.
Published: November 2020

Healthy individuals perform a task such as hitting the head of a nail with an infinite coordination spectrum. This motor redundancy is healthy and allows for learning through exploration and uniform load distribution across muscles. Assessing movement complexity within repetitive movement trajectories may provide insight into the available motor redundancy during aging. We quantified complexity of repetitive arm elevation trajectories in the aging shoulder and assessed test–retest reliability of this quantification. In a cross‐sectional study using 3D‐electromagnetic tracking, 120 asymptomatic subjects, aged between 18 and 70 years performed repetitive abduction and forward/anteflexion movements. Movement complexity was calculated using the Approximate Entropy (ApEn‐value): [0,2], where lower values indicate reduced complexity. Thirty‐three participants performed the protocol twice, to determine reliability (intraclass correlation coefficient [ICC]). The association between age and ApEn was corrected for task characteristics (e.g., sample length) with multiple linear regression analysis. Reproducibility was determined using scatter plots and ICC's. Higher age was associated with lower ApEn‐values during abduction (unstandardized estimate: −0.003/year; 95% confidence interval: [−0.005; −0.002]; p < .001). ICC's revealed poor to good reliability depending on differences in sample length between repeated measurements. The results may imply more stereotype movement during abduction in the ageing shoulder, making this movement prone to the development of shoulder complaints. Future studies may investigate the pathophysiology and clinical course of shoulder complaints by assessment of movement complexity. To this end, the ApEn‐value calculated over repetitive movement trajectories may be used, although biasing factors such as sample length should be taken into account.
Stability indicating RP‐HPLC method for determination of dimethyl fumarate in presence of its main degradation products: Application to degradation kinetics
Authors: Habib Ahmed A , Hammad Sherin F , Amer Mona M , Kamal Amira H
Published: November 2020

A stability‐indicating reverse phase‐high‐perfromance liquid chromatography method for the quantitative determination of dimethyl fumarate in presence of its main degradation products was developed. The chromatographic conditions were optimized using two‐level full factorial design, chromatographic analysis was performed using Inertsil® column (250 × 4.6 mm, 5 μm) maintained at 25°C. Mobile phase was a mixture of water (pH 2.6 adjusted with phosphoric acid) and methanol (40:60, v/v) at a flow rate 1.0 mL/min, detection was performed at 210 nm using diode array detector. Stress degradation of dimethyl fumarate under acidic, alkaline, neutral, oxidative, photolytic, and thermal conditions was carried out, it was found to be very susceptible to hydrolysis under acidic and alkaline conditions; further investigation of degradation kinetics over pH range 1–9 was carried out. The degradation rate constant (K), t1/2 and t90 were calculated. Dimethyl fumarate show decreasing in stability in the following pH order: 7 < 5 < 3 < 1 < 9. The method was validated as per ICH guidelines, the method was found to be linear over concentration range 10–150 μg/mL with coefficient of determination (r2) 0.9997. The method was successfully applied for dimethyl fumarate determination in Marclerosis® dosage form within run time less than eight minutes without interference from excipients.
Cheminformatics Analysis of Fluoroquinolones and their Inhibition Potency Against Four Pathogens
Authors: Borrel Alexandre , Melander Christian , Fourches Denis
Published: November 2020

Drug‐resistant bacteria are a worldwide public health concern. As the prevalence of multi‐drug resistant pathogens outpaces the discovery of new antibacterials, it is of importance to explore the structure‐activity relationships for series of known bactericides with proven scaffolds. Herein, we assembled a set of 507 fluoroquinolone analogues all experimentally tested for their inhibition potency against four pathogens: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pneumoniae. We relied on cheminformatics techniques to characterize and cluster them based on their structural similarity and analyzed the structure‐activity relationships identified for each cluster of fluoroquinolones. Then, we utilized machine learning techniques to develop and validate predictive QSAR models for computing the inhibition potencies (pMIC) of analogues for each pathogen. These QSAR models afforded reasonable external prediction performances (R2≥0.6, MAE∼0.4). This study confirmed that (i) there are both global and local inter‐pathogen concordance regarding the antibacterial potency of fluoroquinolones, (ii) small clusters of fluoroquinolone analogues are characterized by unique patterns of strain selectivity and potency, the latter being potentially useful to design new analogues with enhanced potency and/or selectivity towards a given pathogen, and (iii) robust QSAR models were obtained allowing for future design of new bioactive fluoroquinolones.
Ion collection efficiency of ionization chambers in ultra‐high dose‐per‐pulse electron beams
Authors: Kranzer Rafael , Poppinga Daniela , Weidner Jan , Schüller Andreas , Hackel Thomas , Looe Hui Khee , Poppe Björn
Published: November 2020

Purpose

The ion collection efficiency of vented ionization chambers has been investigated in an ultra‐high dose‐per‐pulse (DPP) electron beam. The role of the chamber design and the electric field strength in the sensitive air volume have been evaluated.

Methods

An advanced Markus chamber and three specially designed parallel plate air‐filled ionization chambers (EWC: End Window Chamber) with varying electrode distance of 0.5, 1, and 2 mm have been investigated. Their ion collection efficiencies were determined experimentally using two methods: extrapolation of Jaffé plots and comparison against a DPP‐independent reference detector. The latter was achieved by calibrating a current transformer against alanine dosimeters. All measurements were performed in a 24 MeV electron beam with DPP values between 0.01 and 3 Gy. Additionally, the numerical approach introduced by Gotz et al. was implemented taking into account space charge effects at these ultra‐high DPPs. The method has been extended to obtain time‐resolved and position‐dependent electric field distortions within the air cavity.

Results

The ion collection efficiency of the investigated ionization chambers drops significantly in the ultra‐high DPP range. The extent of this drop is dependent on the electrode distance, the applied chamber voltage and thus the field strength in the sensitive air volume. For the Advanced Markus chamber, a good agreement between the experimental, numerical and the results of Petersson et al. could be shown. Using the three EWCs with different electrode spacing, an improvement of the ion collection efficiency and a reduction of the polarity effect with decreasing electrode distance could be demonstrated. Furthermore, the results revealed that the determination of the ion collection efficiency from the Jaffé plots and therefore also from two‐voltage method typically underestimate the ion collection efficiency in the region of high dose‐per‐pulse (3 to 130 mGy) and overestimate the ion collection efficiency at ultra‐high dose‐per‐pulse (>1 Gy per pulse).

Conclusions

In this work, the ion collection efficiency determined with different methods and ionization chambers have been compared and discussed. As expected, an increase of the electric field in the ionization chamber, either by applying a higher bias voltage or a reduction of the electrode distance, improves the ion collection efficiency and also reduces the polarity effect. For the Advanced Markus chamber, the experimental results obtained by comparison against a reference agree well with the numerical solution. Based on these results, it seems possible to keep the recombination loss less than or equal to 5% up to a dose‐per‐pulse of 3 Gy with an appropriately designed ionization chamber, which corresponds to the level accepted in conventional radiotherapy dosimetry protocols.
Time‐evolving coupling functions for evaluating the interaction between cerebral oxyhemoglobin and arterial blood pressure with hypertension
Authors: Li Wenhao , Zhang Ming , Huo Congcong , Xu Gongcheng , Chen Wei , Wang Daifa , Li Zengyong
Published: November 2020

Purposes

This study aimed to investigate the network coupling between arterial blood pressure (ABP) and changes in cerebral oxyhemoglobin concentration (Δ [O2Hb]/Δ [HHb]) oscillations based on dynamical Bayesian inference in hypertensive subjects.

Methods

Two groups of subjects, consisting of 30 healthy (Group Control, 55.1 ± 10.6 y), and 32 hypertensive individuals (Group AH, 58.9 ± 8.7 y), participated in this study. A functional near‐infrared spectroscopy system was used to measure the Δ [O2Hb] and Δ [HHb] signals in the bilateral prefrontal cortex (LPFC/RPFC), motor cortex (LMC/RMC), and occipital lobe (LOL/ROL) during the resting state (12 min). Based on continuous wavelet analysis and coupling functions, the directed coupling strength (CS) between ABP and cerebral hemoglobin was identified and analyzed in three frequency intervals (I: 0.6–2 Hz, II: 0.145–0.6 Hz, III: 0.01–0.08 Hz). The Pearson correlations between the CS and blood pressure parameters were calculated in the hypertension group.

Results

In interval I, Group AH exhibited a significantly higher CS for the coupling from ABP to Δ [O2Hb] than Group Control in LMC, RMC, LOL, and ROL. In interval III, the CS from ABP to Δ [O2Hb] in LPFC, RPFC, LMC, RMC, LOL, and ROL was significantly higher in Group AH than in Group Control. For the patients with hypertension, diastolic blood pressure was negatively and pulse pressure was positively related to the CS from ABP to Δ [O2Hb] oscillations in interval III.

Conclusions

The higher CS from ABP to Δ [O2Hb] in interval I indicated that the components of cardiac activity in cerebral hemoglobin oscillations were more directly responsive to the changes in systematic ABP in patients with hypertension than in healthy subjects. Meanwhile, the higher CS from ABP to Δ [O2Hb] in interval III indicated that the cerebral hemoglobin oscillations were susceptible to changes in blood pressure in hypertensive subjects. The results may serve as evidence of impairment in cerebral autoregulation after hypertension. The Pearson correlation results showed that diastolic blood pressure and pulse pressure might be regarded as predictors of cerebral autoregulation function in patients with hypertension, and may be useful for hypertension stratification. This study provides novel insights into the interaction mechanism between ABP and cerebral hemodynamics and could help in the development of new assessment techniques for cerebral vascular disease.
Free‐breathing diffusion tensor MRI of the whole left ventricle using second‐order motion compensation and multitasking respiratory motion correction
Authors: Nguyen Christopher T. , Christodoulou Anthony G. , Coll‐Font Jaume , Ma Sen , Xie Yibin , Reese Timothy G. , Mekkaoui Choukri , Lewis Gregory D. , Bi Xiaoming , Sosnovik David E. , Li Debiao
Published: November 2020

Purpose

We aimed to develop a novel free‐breathing cardiac diffusion tensor MRI (DT‐MRI) approach, M2‐MT‐MOCO, capable of whole left ventricular coverage that leverages second‐order motion compensation (M2) diffusion encoding and multitasking (MT) framework to efficiently correct for respiratory motion (MOCO).

Methods

Imaging was performed in 16 healthy volunteers and 3 heart failure patients with symptomatic dyspnea. The healthy volunteers were scanned to compare the accuracy of interleaved multislice coverage of the entire left ventricle with a single‐slice acquisition and the accuracy of the free‐breathing conventional MOCO and MT‐MOCO approaches with reference breath‐hold DT‐MRI. Mean diffusivity (MD), fractional anisotropy (FA), helix angle transmurality (HAT), and intrascan repeatability were quantified and compared.

Results

In all subjects, free‐breathing M2‐MT‐MOCO DT‐MRI yielded DWI of the entire left ventricle without bulk motion‐induced signal loss. No significant differences were seen in the global values of MD, FA, and HAT in the multislice and single‐slice acquisitions. Furthermore, global quantification of MD, FA, and HAT were also not significantly different between the MT‐MOCO and breath‐hold, whereas conventional MOCO yielded significant differences in MD, FA, and HAT with MT‐MOCO and FA with breath‐hold. In heart failure patients, M2‐MT‐MOCO DT‐MRI was feasible yielding higher MD, lower FA, and lower HAT compared with healthy volunteers. Substantial agreement was found between repeated scans across all subjects for MT‐MOCO.

Conclusion

M2‐MT‐MOCO enables free‐breathing DT‐MRI of the entire left ventricle in 10 min, while preserving quantification of myocardial microstructure compared to breath‐held and single‐slice acquisitions and is feasible in heart failure patients.
Movements and Macrohabitat Use of Alligator Gar in Relation to a Low Head Lock and Dam System
Authors: Lochmann Steve , Brinkman Eric L. , Hann Dylan A.
Published: November 2020

Loss of habitat, targeted removals, and overharvest has contributed to the decline of Alligator Gar Atractosteus spatula. There is agreement among commercial fishers, some recreational anglers, conservationists, and natural resource managers that this species warrants conservation. Appropriate management actions require research to further understand the life history and ecology of Alligator Gar populations. We conducted a movement study of 16 Alligator Gar in the lower Ouachita River, Arkansas–Louisiana, for 1 year using acoustic telemetry. The Alligator Gar were stationary at least 28% of the year. We documented 1,552 movement events during the study. The mean (SD) movement rate during the movement events was 1.13 (0.18) km/h, but it varied among individuals. Only 2 of the 16 Alligator Gar were detected upstream of Felsenthal Dam. The tailwater habitat just below Felsenthal Dam was used heavily by the Alligator Gar. The linear home range was 11.9 (7.1) river kilometers. Due to the hydrology of the system, access to the floodplain is not a hindrance to the lateral movement of Alligator Gar in the Ouachita River. The Felsenthal Dam did seem to hinder longitudinal movement, even though high water allowed the fish to move over and around the dam during spring and early summer. Management plans to rebuild Alligator Gar populations in regulated river systems should consider the negative consequences of barriers to lateral or longitudinal movement.
Evaluation of Management Strategies for an Incidental Catch-and-Release Steelhead Fishery
Authors: McCormick Joshua L. , Dobos Marika E. , Bowersox Brett J. , Copeland Timothy
Published: November 2020

Managing fisheries for species of conservation concern, such as steelhead Oncorhynchus mykiss fisheries in Idaho where wild steelhead are incidentally caught and released, requires a tradeoff between providing opportunity for anglers to fish for hatchery-origin steelhead and managing conservation risk for wild steelhead. Understanding population-level effects of catch-and-release fishing is critical for effectively balancing this tradeoff. We used an integrated population model to evaluate population-level effects of incidental catch-and-release mortality on steelhead in Idaho and assessed the effectiveness of alternative management strategies for meeting fishery and population objectives. When simulated catch-and-release mortality or encounter rates were low, fishery, abundance, and conservation risk objectives were easily met by implementing fisheries annually, regardless of adult abundance. However, when simulated catch-and-release mortality rates were high, management strategies that required the population to surpass minimum thresholds for pre-season abundance were more likely to meet goals for minimizing conservation risk but limited fishing opportunity substantially. Results of this study provide managers with a framework that can be used to manage fisheries to meet fishery goals in the form of hatchery steelhead harvest while maintaining sustainable populations and minimizing risk to wild steelhead. The results also suggest that when implemented properly, it is possible to meet fisheries and conservation objectives simultaneously.
Movement and Space Use of Grass Carp in the Sandusky River, Ohio: Implications for Lake Erie Eradication Efforts
Authors: Harris Cleyo , Brenden Travis O. , Vandergoot Christopher S. , Faust Matthew D. , Herbst Seth J. , Buszkiewicz John T. , Nathan Lucas R. , Fischer Jason L. , Krueger Charles C.
Published: November 2020

The Grass Carp Ctenopharyngodon idella is an invasive species to the Laurentian Great Lakes that was first detected in the 1980s. The western basin of Lake Erie is the putative invasion front for the Great Lakes, with spawning known to occur in two of the basin’s tributaries (Sandusky and Maumee rivers). Targeted removal is being used to reduce Grass Carp abundance, with an ultimate aim of eradication in part to prevent spread and establishment in the other Great Lakes; response efforts are being concentrated in the Sandusky River due to its heavy use by Grass Carp and because it is the tributary where spawning occurs consistently. The goal of this research was to identify areas in the Sandusky River where Grass Carp aggregate and identify variables that influence movement to improve efficiency of response efforts. Movement and space use of 27 Grass Carp were monitored using acoustic telemetry. Detection data were used to estimate movement and daily detection rates and also used in a spatial capture–recapture model to estimate activity centers of tagged fish. Grass Carp movement was highest when daily discharge and water temperature exceeded 31 m3/s and 18°C, respectively, and next highest when discharge exceeded 31 m3/s and temperature was between 4.5°C and 18.0°C. Daily detection rates at receivers and concentrations of activity centers suggested that aggregations occurred between river kilometers (RKMs) 34 and 36 and at RKM 45. During spawning conditions, Grass Carp also aggregated near RKM 48.6, which is proximal to suspected spawning locations. We recommend concentrating response efforts in these general locations and using passive capture gear when Grass Carp are the most mobile. Response efforts could be further refined by using a variety of acoustic telemetry monitoring techniques, including fine-scale positioning, real-time receivers, and mobile tracking to provide precise location and timing for removal actions.
Simple (thienylmethylene)oxindole‐based polymer materials as donors for efficient non‐fullerene polymer solar cells
Authors: Li Hongneng , Sun Rui , Wang Wei , Wu Yao , Wang Tao , Min Jie
Published: November 2020

Although the significant progress in the power conversion efficiencies (PCEs) of non‐fullerene polymer solar cells (PSCs) has proved their commercial potential, the development of efficient photovoltaic materials from easily available raw materials and simple chemical synthesis is still lagging. In this work, three copolymers donors (PTEI‐H, PTEI‐F, and PTEI‐Cl) based on easily synthesized (Z)‐3‐(thiophen‐2‐yl‐methylene)‐indolin‐2‐one (TEI) as electron‐deficient unit were synthesized and characterized. As compared to the polymer PTEI‐H, the fluorinated and chlorinated polymers (PTEI‐F and PTEI‐Cl) show broader band gaps and deeper HOMO energy levels. However, after blending with small molecule acceptor Y6, the as‐cast PTEI‐H devices exhibit a PCE of 8.27%, outperforming those of the PTEI‐F devices (7.22%) and PTEI‐Cl devices (6.50%). The relatively high photovoltaic performance of the PTEI‐H devices are associated with their increased short‐circuit current density and fill factor values, resulting from the efficient exciton dissociation and charge generation, balanced charge transport properties, and reduced recombination loss. In consideration of the merits of the structural simplicity and synthetic accessibility of TEI unit, we believe it is a potential electron‐deficient moiety in developing high‐performance polymer donors for possible mass‐production of non‐fullerene PSCs.
Heat transfer analysis on MHD flow over a stretchable Riga wall considering Entropy generation rate: A numerical study
Authors: Shah Faisal , Khan Muhammad Ijaz , Chu Yu‐Ming , Kadry Seifedine
Published: November 2020

Current paper explores the MHD two‐dimensional stagnation point flow over a stretchable Riga wall in the presence of porous medium. Cattaneo‐Christove heat and mass flux model is used to examine the heat and mass transfer analysis. Particular interest is paid to the analysis of entropy generation due to heat and mass diffusion. Transformations are used to convert the given partial differential equation into ordinary differential system. The governing equations are solved numerically using the built‐in shooting method. The impacts of emanating parameters are examined through graphs. The impact of various important flow parameters are discussed graphically on the entropy generation, velocity, Bejan number, concentration, and temperature profile.
How can social–ecological system models simulate the emergence of social–ecological crises?
Authors: Brown Calum , Rounsevell Mark
Published: November 2020

The idea that human impacts on natural systems might trigger large‐scale, social–ecological ‘crises’ or ‘breakdowns’ is attracting increasing scientific, societal and political attention, but the risks of such crises remain hard to assess or ameliorate.

Social–ecological systems have complex dynamics, with bifurcations, nonlinearities and tipping points all emerging from the interaction of multiple human and natural processes. Computational modelling is a key tool in understanding these processes and their effects on system resilience. However, models that operate over large geographical extents often rely on assumptions such as economic equilibrium and optimisation in social–economic systems, and mean‐field or trend‐based behaviour in ecological systems, which limit the simulation of crisis dynamics.

Alternative forms of modelling focus on simulating local‐scale processes that underpin the dynamics of social–ecological systems. Recent improvements in data resources and computational tools mean that such modelling is now technically feasible across large geographical extents.

We consider the contributions that the different types of model can make to simulating social–ecological crises. While no models are able to predict exact outcomes in complex social–ecological systems, we suggest that one new approach with substantial promise is hybrid modelling that uses existing model architectures to isolate and understand key processes, revealing risks and associated uncertainties of crises emerging. We outline convergent and efficient functional descriptions of social and ecological systems that can be used to develop such models, data resources that can support them, and possible ‘high‐level’ processes that they can represent.

A free Plain Language Summary can be found within the Supporting Information of this article
The influence of fiber alignment, structure and concentration on mechanical behavior of carbon nanofiber/epoxy composites: Experimental and numerical study
Authors: Chanda Amit , Sinha Sujeet K , Datla Naresh V
Published: November 2020

The mechanical properties of epoxy‐based nanocomposites largely depend on fiber alignment, structure, concentration, and loading condition. To study the influence of these factors on the nonlinear stress‐strain behavior of epoxy nanocomposites, random and aligned carbon nanofiber (CNF)/epoxy composites were fabricated and tested under different strain rates. The elastic modulus and tensile strength were found to be increased as CNF concentrations increased for both random and transversely aligned nanocomposites. This behavior was accurately captured by a three‐dimensional representative volume element (RVE), where the fiber orientation and waviness were modeled from the experimental observation. This RVE predicted the increase in elastic modulus and tensile strength with increase in CNF concentration and strain rate as well as when the CNF alignment changes from transverse to longitudinal.
Digitalising diabetes support groups in response to the coronavirus COVID‐19 outbreak: a collaborative initiative
Authors: Sauchelli Sarah
Published: November 2020

Peer support groups are groups of people who share something in common and use their experiences to help each other. As the pandemic persists and health care teams are adjusting to the changing circumstances, facilitating access to peer support groups that can hold meetings via a digital platform can provide a unique source of additional help for diabetes self‐management and mental wellbeing.