bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting Platinum Dissolution and Performance Degradation under Drive Cycle Operation of Polymer Electrolyte Fuel Cells
Authors: Baroody Heather A. , Kjeang Erik
Published: April 2021

A protocol is presented that allows for fuel cell performance degradation to be determined based on a vehicle drive cycle. Four stages are outlined beginning with the conversion of vehicle velocity data to a cell voltage profile. The amount of platinum dissolved in the system and oxide coverage on platinum particles are simultaneously calculated by considering several degradation mechanisms including Ostwald ripening and platinum particles loss to the membrane. The platinum loss is used to determine the Electrochemically Active Surface Area (ECSA) loss in the catalyst layer. The voltage loss due to platinum degradation is then determined from the ECSA data. The results show that longer times at higher upper potential limits lead to more platinum degradation and thus performance loss as expected. Accelerated Stress Test data is reproduced within the acceptable error. The model is applied to real-world data from a vehicle drive cycle showing that the model simplifications and assumptions outlined are reasonable and prove predictive capabilities. Although more experimental data would be beneficial to fully validate the model, the present work provides a complete, physics-based catalyst degradation model that can be integrated with performance models to predict durability and optimize future system designs and operating conditions. This paper is part of the JES Focus Issue on Proton Exchange Membrane Fuel Cell and Proton Exchange Membrane Water Electrolyzer Durability.
Outcome-based student assessment enhances academic performance in basic medical laboratory course
Authors: Li Kai-Feng , Liu Bo-Zhi , Wu Fei-Fei , Sun Xia-Cheng , Tian Fei , Wu You-Sheng , Ji Le-Le , Liu Nan-Nan , Zhang Hai-Feng , Wang Ya-Yun
Published: April 2021

Basic medical laboratory courses (BMLCs) play an important role in medical educational courses helping the student acquire three important skills of surgical operating, collaborative learning, and problem solving. The outcome-based student assessment (OBSA) is a learning evaluation method that establishes specific evaluation points based on performance of students in three aspects: surgical operating, collaborative learning, and problem solving in the BMLC curriculum practices. The purpose of the present randomized controlled trial study is to explore the efficiency of OBSA program in BMLCs. The 233 students attending BMLCs were randomly divided into 2 groups, 118 in the OBSA group and 115 in the control group. We conducted multiple-choice examination questions (MCQs) test and two questionnaires with the method of two-sample t test for statistics. The results of MCQs in total eight BMLC blocks showed that the academic performance of the OBSA group was significantly better than that of the control group ( P < 0.05). In addition, the average scores of direct observation of procedural skills (DOPS) and mini-experimental evaluation exercise in OBSA group were significantly higher than those in control group ( P < 0.05). The majority of the medical students preferred the OBSA and considered OBSA could effectively improve their surgical operating skills (83.9%), collaborative learning skills (92.1%), and problem-solving skills (91.1%). From the above, OBSA is an effective evaluation method for the implementation of the BMLC curriculum.
Nutrition education on obesity and diabetes to medical students
Authors: Pérez-Cornejo Patricia , Corral-Fernandez Nancy E. , Guzman-Hernandez Maria Luisa , Gopalan Chaya
Published: April 2021

It is important for medical students to understand the relationship between nutrition, obesity, and diabetes to educate their patients in the future. However, medical training does not always include nutritional education. An experiential learning project was incorporated into the medical school curriculum as an effort to implement nutrition in the physiology course. First-year medical students ( n = 140) received lectures on the regulation of blood glucose levels and their relationship to carbohydrates with different glycemic indexes (GI), obesity, and diabetes. Lectures were followed by a laboratory exercise where students calculated their body mass index (BMI), percentage body fat, and percentage muscle using a Bioelectrical Impedance Commercial Scale. While 63% of students had normal BMI, 31% were overweight or obese and 5% were underweight. A subgroup of 54 students tested different types of breakfasts with varying GI and provided blood samples at 0, 30, 60, 90, and 120 min. Their glucose responses were plotted based on the breakfast GI. Pre- and posttests were conducted to assess the teaching intervention where the Wilcoxon signed ranks test indicated that posttest ranks were significantly higher than pretest ranks (Z = −6.6, P < 0.001), suggesting the intervention was beneficial to students.
Validating The Core Concept Of “Mass Balance”
Authors: Michael Joel , Modell Harold
Published: April 2021

We have created a conceptual framework for the core concept of “mass balance.” Unlike the previous conceptual frameworks that we have created and validated, the framework for “mass balance” is simply a description in words of the fundamental mass balance equation and the implications of the equation. We surveyed physiology faculty and asked them to rate the importance of “mass balance” as defined by the conceptual framework and also to rate the importance for their students of being able to apply the core concept to liquids, gases, solutes, and solids. Respondents indicated that “mass balance” is important and that our conceptual framework provides a useful tool for teaching and learning. We discuss several examples of how “mass balance” can be used in making sense about a variety of physiological phenomena.
Gastrointestinal jabberwocky to bioengineering design: using function diagrams to teach physiology
Authors: Wilson Thad E. , Barrett Kim E.
Published: April 2021

Function diagrams put the focus on physiology and physiological concepts rather than the associated anatomy. Function diagrams could potentially serve as an elaboration tool and memory aid (mnemonic) to improve learning and recall. The function diagram prototype of the gastrointestinal system can aid in the instruction of difficult gastrointestinal physiology topics using a sequential focus on fundamental gastrointestinal functions.
Zinc pyrithione activates the volume-regulated anion channel through an antioxidant-sensitive mechanism
Authors: Figueroa Eric E. , Denton Jerod S.
Published: April 2021

Leucine-rich repeat-containing 8 (LRRC8) volume-regulated anion channels (VRACs) play important physiological roles in diverse cell types and may represent therapeutic targets for various diseases. To date, however, the pharmacological tools for evaluating the druggability of VRACs have been limited to inhibitors, as no activators of the channel have been reported. We therefore performed a fluorescence-based high-throughput screening (HTS) of 1,184 Food and Drug Administration-approved drugs for compounds that increase VRAC activity. The most potent VRAC potentiator identified was zinc pyrithione (ZPT), which is used commercially as an antifouling agent and for treating dandruff and other skin disorders. In intracellular Yellow Fluorescent Protein YFP(F46L/H148Q/I152L)-quenching assays, ZPT potentiates the rate and extent of swelling-induced iodide influx dose dependently with a half-maximal effective concentration (EC50) of 5.7 µM. Whole cell voltage-clamp experiments revealed that coapplication of hypotonic solution and 30 µM ZPT to human embryonic kidney 293 or human colorectal carcinoma 116 cells increases the rate of swelling-induced VRAC activation by approximately 10-fold. ZPT potentiates swelling-induced VRAC currents after currents have reached a steady state and activates currents in the absence of cell swelling. Neither ZnCl2 nor free pyrithione activated VRAC; however, treating cells with a mixture of ZnCl2 and pyrithione led to robust channel activation. Finally, the effects of ZPT on VRAC were inhibited by reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) and NAD(P)H oxidase inhibitor diphenyleneiodonium chloride, suggesting the mechanism of action involves ROS generation. The discovery of ZPT as a potentiator/activator of VRAC demonstrates the utility of HTS for identifying small-molecule modulators of VRAC and adds to a growing repertoire of pharmacological tool compounds for probing the molecular physiology and regulation of this important channel.
Monochorionic Diamniotic Vasa Previa Pregnancy: A Medical Student Perspective
Authors: Samuel Joshua M. , Ali Fatima , Faro Jonathan , Baum Jonathan D.
Published: April 2021

Monochorionic diamniotic twins and vasa previa are uncommon. We present a case that was followed from ultrasound diagnosis to delivery.
Seismic Evaluation and Retrofit of Reinforced Concrete Buildings with Masonry Infills Based on Material Strain Limit Approach
Authors: Shendkar Mangeshkumar R. , Kontoni Denise-Penelope N. , Mandal Sasankasekhar , Maiti Pabitra Ranjan , Tavasoli Omid
Published: April 2021

The seismic evaluation and retrofit of reinforced concrete (RC) structures considering masonry infills is the correct methodology because the infill walls are an essential part of RC structures and increase the stiffness and strength of structures in seismically active areas. A three‐dimensional four‐storey building with masonry infills has been analyzed with nonlinear static adaptive pushover analysis by using the SeismoStruct software. Two models have been considered in this study: the first model is a full RC‐infilled frame and the second model is an open ground storey RC‐infilled frame. The infill walls have been modeled as a double strut nonlinear cyclic model. In this study, the “material strain limit approach” is first time used for the seismic evaluation of RC buildings with masonry infills. This method is based on the threshold strain limit of concrete and steel to identify the actual damage scenarios of the structural members of RC structures. The two models of the four‐storey RC building have been retrofitted with local and global strengthening techniques (RC‐jacketing method and incorporation of infills) as per the requirements of the structure to evaluate their effect on the response reduction factor (R) because the R‐factor is an important design tool that shows the level of inelasticity in a structure. A significant increase in the response reduction factor (R) and structural plan density (SPD) has been observed in the case of the open ground storey RC‐infilled frame after the retrofit. Thus, this paper aims to present a most effective way for the seismic evaluation and retrofit of any reinforced concrete structure through the material strain limit approach.
Evaluation of the DWT-PCA/SVD Recognition Algorithm on Reconstructed Frontal Face Images
Authors: Asiedu Louis , Essah Bernard O. , Iddi Samuel , Doku-Amponsah K. , Mettle Felix O.
Published: April 2021

The face is the second most important biometric part of the human body, next to the finger print. Recognition of face image with partial occlusion (half image) is an intractable exercise as occlusions affect the performance of the recognition module. To this end, occluded images are sometimes reconstructed or completed with some imputation mechanism before recognition. This study assessed the performance of the principal component analysis and singular value decomposition algorithm using discrete wavelet transform (DWT-PCA/SVD) as preprocessing mechanism on the reconstructed face image database. The reconstruction of the half face images was done leveraging on the property of bilateral symmetry of frontal faces. Numerical assessment of the performance of the adopted recognition algorithm gave average recognition rates of 95% and 75% when left and right reconstructed face images were used for recognition, respectively. It was evident from the statistical assessment that the DWT-PCA/SVD algorithm gives relatively lower average recognition distance for the left reconstructed face images. DWT-PCA/SVD is therefore recommended as a suitable algorithm for recognizing face images under partial occlusion (half face images). The algorithm performs relatively better on left reconstructed face images.
Change of Tensile Properties with Aging Time and Temperature in Al‐Si‐Cu‐Mg 354 Cast Alloys with/without Minor Addition of Ni and/or Zr
Authors: Hernandez-Sandoval J. , Abdelaziz M. H. , Elsharkawi E. A. , Samuel A. M. , Samuel F. H.
Published: April 2021

The principal aim of the present research work was to investigate the effects of minor additions of nickel and zirconium on the strength of cast aluminum alloy 354 at room temperature (25°C). A decrease in tensile properties of ∼10% with the addition of 0.4 wt.% nickel is attributed to a nickel‐copper reaction which interferes with the formation of Al2Cu precipitates. The platelet‐like phases (Al,Si)3(Zr,Ni,Fe) and (Al,Si)3(Zr,Ti) are the main features observed in the microstructures of the tensile samples of alloys with Zr additions. The reduction in mechanical properties is due to the increase in the percentage of intermetallic phases formed during solidification; such particles would act as stress concentrators, decreasing the alloy ductility. The main effect of Zr addition lies in a significant reduction in the alloy grain size ∼40%, rather than an increase in the mechanical properties. Quality index charts could be used in assessing the effects of the Ni and Zr additions to the base alloy, as well as evaluating the heat treatment relationships to the alloy tensile properties, in particular when the system shows multiple precipitation reactions. Due to the high liquidus temperature of the Al‐Zr binary phase diagram, addition of Zr beyond 0.2% is not recommended to avoid undissolved Zr.
Rotation Speed Control of the Rotary Valve in MWD Tools Based on Speed Feedforward Compensation
Authors: Zhang Lingtan , Shen Yue , Wang Long , Jia Jia , Wei Lingzhi
Published: April 2021

The rotary valve speed control, seriously affected by the nonlinear characteristic of rotary valve load torque, affects the generation of drilling fluid pressure phase shift keying (PSK) signal and its quality. The calculation model feedforward of the load torque acts on the speed control system and enables the motor voltage to change according to the law of calculation model, and the linearization correction of the speed system is performed. Additionally, the flow measurement is introduced into the calculation model of the load torque to track the load torque change with the flow, suppressing the influence of large changes in flow rate on open-loop control of rotary valve speed. The closed-loop proportional-integral-derivative (PID) control is formed by negative feedback of speed, and the PID parameter value rule is established based on the rapid decay control of transient component in the rotary valve speed step response, which speeds up the tracking of the rotary valve speed following the control voltage pulse and reduces the distortion of the drilling fluid pressure PSK signal, increasing the frequency of the drilling fluid pressure carrier and improving the transmission rate of downhole information. Simulink simulation indicates that the closed-loop PID control of rotary valve speed can track the change of control voltage pulse quickly and strongly suppress the interference influences from flow measurement error and load torque calculation model deviation.
Resource Allocation for SWIPT Systems with Nonlinear Energy Harvesting Model
Authors: Hu Yifan , Liu Mingang , Feng Yizhi
Published: April 2021

In this paper, we study the resource allocation for simultaneous wireless information and power transfer (SWIPT) systems with the nonlinear energy harvesting (EH) model. A simple optimal resource allocation scheme based on the time slot switching is proposed to maximize the average achievable rate for the SWIPT systems. The optimal resource allocation is formulated as a nonconvex optimization problem, which is the combination of a series of nonconvex problems due to the binary feature of the time slot‐switching ratio. The optimal problem is then solved by using the time‐sharing strong duality theorem and Lagrange dual method. It is found that with the proposed optimal resource allocation scheme, the receiver should perform EH in the region of medium signal‐to‐noise ratio (SNR), whereas switching to information decoding (ID) is performed when the SNR is larger or smaller. The proposed resource allocation scheme is compared with the traditional time switching (TS) resource allocation scheme for the SWIPT systems with the nonlinear EH model. Numerical results show that the proposed resource allocation scheme significantly improves the system performance in energy efficiency.
Impact of Personal Protection Habits on the Spread of Pandemics: Insights from an Agent-Based Model
Authors: Álvarez-Pomar Lindsay , Rojas-Galeano Sergio
Published: April 2021

Background. After several waves of spread of the COVID-19 pandemic, countries around the world are struggling to regain their economies by slowly lifting mobility restrictions and social distance measures applied during the crisis. Meanwhile, recent studies provide compelling evidence on how contact distancing, the use of face masks, and handwashing habits can reduce the risk of SARS-CoV-2 transmission. In this context, we investigated the effect that these personal protection habits can have in preventing new waves of contagion. Methods. We extended an agent-based COVID-19 epidemic model in a simulated community to incorporate the mechanisms of these aforementioned personal care habits and measure their incidence in person-to-person transmission. A full factorial experiment design was performed to illustrate the extent to which the interplay between these personal habits is effective in mitigating the spread of disease. A global sensitivity analysis was performed on the parameters that control these habits to further validate the results. Results. We found that observing physical distance is the dominant habit in reducing disease transmission, although adopting either or both of the other two habits is necessary to some extent to suppress a new outbreak entirely. When physical distance is not observed, adherence to the use of masks or handwashing has a significant decrease in infections and mortality, but the epidemic still unfolds. We also found that in all scenarios, the combined effect of adhering to the three habits is more powerful than adopting them separately. Conclusions. Our findings suggest that a broad adherence of the population to voluntary self-care habits would help contain unfold of new outbreaks. The purpose of our model is illustrative and contributes to ratify the importance of urging citizens to adopt the amalgam of personal care habits as a primary collective protection measure to prevent communities from returning to confinements, while immunisation is carried out in late stages of the pandemic.
Wear Characteristics of Dense Fine Particles Solid‐Liquid Two‐Phase Fluid Centrifugal Pump with Open Impellers
Authors: Wang Yanping , Han Chuanfeng , Zhou Ye , Lin Zhe , Ma Jianfeng , Li Xiaojun , Zhang Wei
Published: April 2021

The demand for a centrifugal pump with open impellers for conveying dense fine particles in solid‐liquid two‐phase flow has increased significantly in actual engineering. The wear of dense fine particles on the centrifugal pump is also exceedingly prominent, which affects the engineering efficiency and economic benefits. The two‐phase flow in the open centrifugal pump is three‐dimensional and unsteady; the movement of high‐volume concentration particles in the centrifugal pump and its mutual influence on the two‐phase flow, which results in the calculation of wear, are very intricate. To study the wear characteristics of the centrifugal pump with open impeller with high‐volume concentration particles more accurately, numerical simulation and experimental comparison are carried out for the impeller wear of dense fine particles transported by the centrifugal pump with open impellers. Considering the relationship between particles and walls, we used the Fluent 18.0 built‐in rebound function and wear model. The RNG k‐ε model and the DDPM model were adopted in the numerical simulation, and the numerical solution for centrifugal pump wear was performed under flow rate (9.6 m3·h−1, 12.8 m3·h−1, 16 m3·h−1, and 19.2 m3·h−1), different particle sizes (0.048 mm, 0.106 mm, 0.15 mm, 0.27 mm, and 0.425 mm), and different particle volume concentrations (10%, 15%, 20%, 25%, and 30%), respectively. By comparing the serious wear positions of the impeller, the experimental results correspond well with the numerical simulation, which can be used to predict and study the wear characteristics of the impeller. The results show that the most serious area of blade wear is the middle part of the pressure surface, followed by the middle part of the upper part of the blade. The wear of the impeller is greatly affected by relevant parameters, such as pump flow rate, particle diameter, and particle volume concentration. These results can provide some basis for the wear‐resistant design of dense fine particle impeller.
Magnetohydrodynamic Fluctuating Free Convection Flow of Second-Grade Fluid Flow in a Porous Medium
Authors: Ali Farhad , Khan Momin , Gohar Madeha
Published: April 2021

The article’s objective is to study the magnetohydrodynamic fluctuating free convection flow of incompressible electrically conducting viscoelastic fluid in a porous medium in the presence of a pressure gradient. The flow is between two parallel plates; the lower plate is at rest, while the upper plate moves with a free stream velocityUt. A uniform magnetic field of strength B0 is applied transversely to the fluid motion. The dimensional governing equations and physical initial and boundary conditions are nondimensionalized by inserting appropriate dimensionless variables. Furthermore, Lighthill’s method is used to obtain exact analytical solutions for the velocity, temperature, and concentration distributions. Finally, the influences of inserted parameters are studied through plots and discussed physically. The numerical results are calculated and presented in tabular form for skin friction. It is worth mentioning that when the viscoelastic parameterα1tends to zero, the obtained general solution is reduced to Newtonian fluid, which shows the validity and correctness of our obtained exact solutions.
Monte Carlo Node Localization Based on Improved QUARTE Optimization
Authors: Song Ling , Jiang Xiaoyu , Wang Liying , Hu Xiaochun
Published: April 2021

Wireless sensor network (WSN) is a research hot spot of scholars in recent years, in which node localization technology is one of the key technologies in the field of wireless sensor network. At present, there are more researches on static node localization, but relatively few on mobile node localization. The Monte Carlo mobile node localization algorithm utilizes the mobility of nodes to overcome the impact of node velocity on positioning accuracy. However, there are still several problems: first, the demand for anchor nodes is large, which makes the positioning cost too high; second, the sampling efficiency is low, and it is easy to fall into the infinite loop of sampling and filtering; and third, the positioning accuracy and positioning coverage are not high. In order to solve the above three problems, this paper proposes a Monte Carlo node location algorithm based on improved QUasi‐Affine TRansformation Evolutionary (QUATRE) optimization. The algorithm firstly selects the high‐quality common nodes in the range of one hop of unknown nodes as temporary anchor nodes, and takes the temporary anchor nodes and anchor nodes as the reference nodes for positioning, so as to construct a more accurate sampling area; then, the improved QUATRE optimization algorithm is used to obtain the estimated location of unknown nodes in the sampling area. Simulation experiments show that the Monte Carlo node positioning algorithm based on the improved QUATRE optimization has higher positioning accuracy and positioning coverage, especially when the number of anchor nodes is relatively small.
Behaviour of Precast Column Foundation Connection under Reverse Cyclic Loading
Authors: Hemamathi L. , Jaya K. P.
Published: April 2021

Precast column foundation connection is one of the critical connections under reverse cyclic loading, and the present study focuses on this connection. Three types of connections were considered, such as (i) base plate connection, (ii) pocket connection, and (iii) grouted sleeve connection. All the above connections were designed, and experimental investigation was carried out on 1 : 2 scaled models by subjecting the column to lateral reverse cyclic loading. Displacement‐controlled loading pattern has been adopted for the testing of the specimens. The structural response of the connection was studied for their (i) load‐displacement hysteresis behaviour, (ii) stiffness degradation, (iii) energy dissipation, and (iv) ductility. The results were then compared with that of the monolithic connection. The precast connection was more ductile, and the energy dissipated by the pocket connection was high compared to the base plate and grouted sleeve connection. The ductility and the load‐carrying of grouted sleeve connection were small compared to other connections. The results of the study showed the precast column foundation can be used in seismic prone areas.
Idiopathic Sclerosing Encapsulating Peritonitis in a Patient with Atypical Symptoms and Imaging Findings
Authors: Wetherell Joseph , Woolley Katherine , Chadha Rishi , Kostka Julia , Adilovic Edin , Nepal Pankaj
Published: April 2021

Sclerosing encapsulating peritonitis is a rare condition caused by a fibrotic membrane covering the small bowel which may lead to abdominal pain or obstruction. The cause may be primary and idiopathic or secondary to several diseases, treatments, and/or medications. The condition typically presents with bowel obstruction, and only one previous case has described ascites as the presenting sign. Sclerosing encapsulating peritonitis is typically diagnosed intraoperatively. We present a case of a patient who presented with atypical clinical symptoms including respiratory distress, recurrent abdominal ascites, and failure to thrive who was diagnosed nonoperatively.
Studying Three Abstract Artists Based on a Multiplex Network Knowledge Representation
Authors: Gutiérrez Luis Fernando , Zarama Roberto , Valdivia Juan Alejandro
Published: April 2021

Discovering the influences between paintings and artists is very important for automatic art analysis. Lately, this problem has gained more importance since research studies are looking into explanations about the origin and evolution of artistic styles, which is a related problem. This paper proposes to build a multiplex artwork representation based on artistic formal concepts to gain more understanding about the aforementioned problem. We complement and built our approach on the previous notion of Creativity Implication Network. We used the recently proposed MultiRank algorithm to suggest possible explanations of the dynamic of some artistic styles. Our results corroborate some well‐known facts about the artists analyzed and give qualitative and quantitative information that show the possibilities and strengths of the proposed framework. We plan to expand our analysis to include more abstract artworks. Ideally, we are going to be able to validate more our results and test how our methodology could be used to generate visual artifacts too.
Liraglutide Regulates the Kidney and Liver in Diabetic Nephropathy Rats through the miR-34a/SIRT1 Pathway
Authors: Xiao Shan , Yang Ye , Liu Yue-Tong , Zhu Jun
Published: April 2021

Purpose. To explore the regulatory effects of liraglutide on the kidney and liver through the miR-34a/SIRT1 pathway with related factors in diabetic nephropathy (DN) rats. Methods. DN rats were randomly divided into two groups (

n
=
10

) and were injected with liraglutide or normal saline twice a day. The 24-hour urine microalbumin content and biochemical index levels were measured. qRT-PCR was performed to detect the expression of miR-34a in the kidney and liver tissues. The levels of SIRT1, HIF-1a, Egr-1, and TGF-β1 in kidney and liver tissues were determined using qRT-PCR, western blot, and immunohistochemistry. Electron microscopy and HE staining were used to observe the ultrastructure and pathological changes. Results. Liraglutide treatment in DN rats decreased blood glucose, 24-hour urine microalbumin, TC, TG, LDL-C, UA, Cr, UREA, ALT, and AST levels and increased the level of HDL-C (

P
<
0.05

). Compared with the control group, the miR-34a levels were significantly decreased in kidney and liver tissues followed by liraglutide treatment (

P
<
0.05

). The levels of SIRT1 in the liraglutide group are significantly higher than those in the control group with the kidney and liver tissues (

P
<
0.05

). Conversely, the contents of HIF-1a, Egr-1, and TGF-β1 were significantly lower in the liraglutide group than in the control group (

P
<
0.05

). Electron microscopy showed that the kidney of the liraglutide-treated group exhibited minor broadening of the mesangial areas, fewer deposits, and a well-organized foot process. HE staining revealed that the kidney of the liraglutide-treated rats had a more regular morphology of the glomerulus and Bowman sac cavity and lighter tubular edema. Additionally, the liraglutide-treated DN rats had a clear hepatic structure, a lower degree of steatosis, and mild inflammatory cell infiltration. Conclusion. Liraglutide, through its effect on the miR-34a/SIRT1 pathway, may have a protective role in the kidney and liver of DN rats.
A Case of Large Aplasia Cutis Congenita with Underlying Skull Defect: Effective Surgical Treatment with Integra® Dermal Regeneration Template
Authors: Scotti Andrea , Benanti Elisa , Augelli Federica , Baruffaldi Preis Franz Wilhelm
Published: April 2021

Introduction: Aplasia cutis congenita (ACC) is a rare congenital abnormality characterized by the absence of a portion of skin at birth which most commonly involves the scalp and can affect the galea, the pericranium, the bone, and the dura mater. It can be an isolated condition or associated with other disorders. Case Report: We present a case of ACC with a large defect of the scalp and the underlying bone treated with the use of Integra® Dermal regeneration template. At 5 months of follow-up, the wound is completely healed and the bony defect greatly reduced. Contraction of the area of alopecia was observed. Discussion: Several surgical and conservative options have been described to treat this congenital condition: advanced dressing, skin graft, local flaps, free flaps, and other methods. In our case, we used Integra® Dermal templates which provide a barrier for infections, promote cellular activity for a rapid vascularization, and improve healing.
Long Noncoding RNA SPRY4-IT1 Modulates Ketamine-Induced Neurotoxicity in Human Embryonic Stem Cell-Derived Neurons through EZH2
Authors: Huang Jingyuan , Xu Yan , Wang Fang , Wang Haili , Li Lu , Deng Yanan , Cai Liang
Published: April 2021

Objective: This study aimed to investigate whether long noncoding RNA sprouty receptor tyrosine kinase signaling antagonist 4-intronic transcript 1 (SPRY4-IT1) is involved in the regulation of ketamine-induced neurotoxicity. Methods: Human embryonic stem cells (hESCs) were induced into neurons in vitro and treated with ketamine. Apoptosis and neurite degeneration assays were used to determine ketamine-induced neurotoxicity and qRT-PCR to determine SPRY4-IT1 expression. SPRY4-IT1 was downregulated in hESC-induced neurons to examine its regulation on ketamine-induced neurotoxicity. The correlation between enhancer of zeste homolog 2 (EZH2) and SPRY4-IT1 was also examined. EZH2 was upregulated in SPRY4-IT1-downregualted hESC-induced neurons to further examine its participation in SPRY4-IT1-mediated ketamine neurotoxicity. Results: Ketamine-induced dose-dependent apoptosis, neurite degeneration, and SPRY4-IT1 upregulation in hESC-induced neurons. Lentivirus-mediated SPRY4-IT1 downregulation protected ketamine neurotoxicity. EZH2 expression was positively correlated with SPRY4-IT1 in hESC-induced neurons. EZH2 overexpression markedly reversed the protective effects of SPRY4-IT1 knockdown on ketamine neurotoxicity. Conclusions: SPRY4-IT1 is involved in anesthesia-induced neurotoxicity, possibly through the regulation on EZH2 gene.
Severity of Small Vessel Disease Biomarkers Reduces the Magnitude of Cognitive Recovery after Ischemic Stroke
Authors: Sagnier Sharmila , Catheline Gwenaëlle , Munsch Fanny , Bigourdan Antoine , Poli Mathilde , Debruxelles Sabrina , Renou Pauline , Olindo Stéphane , Rouanet François , Dousset Vincent , Tourdias Thomas , Sibon Igor
Published: April 2021

Objective: The objective of this study was to evaluate the impact of radiological biomarkers suggestive of cerebral small vessel disease (SVD) on the evolution of cognitive performances after an ischemic stroke (IS). Methods: We studied patients with a supratentorial IS recruited consecutively to a prospective monocentric longitudinal study. A cognitive assessment was performed at baseline, 3 months, and 1 year and was based on a Montreal Cognitive Assessment, an Isaacs set test of verbal fluency (IST), and a Zazzo’s cancellation task (ZCT) for the evaluation of attentional functions and processing speed. The following cerebral SVD biomarkers were detected on a 3-T brain MRI performed at baseline: white matter hyperintensities (WMHs), deep and lobar microbleeds, enlarged perivascular spaces in basal ganglia and centrum semiovale, previous small deep infarcts, and cortical superficial siderosis (cSS). Generalized linear mixed models were used to evaluate the relationship between these biomarkers and changes in cognitive performances. Results: A total of 199 patients (65 ± 13 years, 68% male) were analyzed. Overall, the cognitive performances improved, more significantly in the first 3 months. Severe WMH was identified in 34% of the patients, and focal cSS in 3.5%. Patients with severe WMH and focal cSS had overall worse cognitive performances. Those with severe WMH had less improvement over time for IST (β = −0.16, p = 0.02) and the number of errors to ZCT (β = 0.19, p = 0.02), while those with focal cSS had less improvement over time for ZCT completion time (β = 0.14, p = 0.01) and number of errors (β = 0.17, p = 0.008), regardless of IS volume and location, gray matter volume, demographic confounders, and clinical and cardiovascular risk factors. Conclusion: The severity of SVD biomarkers, encompassing WMH and cSS, seems to reduce the magnitude of cognitive recovery after an IS. The detection of such SVD biomarkers early after stroke might help to identify patients with a cognitive vulnerability and a higher risk of poststroke cognitive impairment.
Feasibility and Oncologic Outcome of Salvage Surgery in Isolated Seminal Vesicle Remnants after Radical Prostatectomy
Authors: Pfister David , Nestler Tim , Hartmann Florian , Haidl Friederike , Pullankavumkal Jasmin , Schmidt Matthias , Heidenreich Axel
Published: April 2021

Background: To demonstrate the feasibility of resecting isolated locally relapsing seminal vesicle remnants after primary radical prostatectomy and radiotherapy. Early oncologic outcomes and prognostic risk factors for relapse are demonstrated. Objectives and Methods: A total of 32 patients underwent open resection of locoregional prostate cancer recurrence in seminal vesicles, as documented on either MRI, 11C-choline, or 68Ga-PSMA PET/CT scans. Age, PSA-DT, PSA, and time to recurrence after primary treatment resection status were used in a uni- and multivariate Cox regression analysis for biochemical relapse after surgery. Results: Median patient age at time of salvage surgery was 70 (57–77) years. Median PSA and PSA-DT was 2.79 (0.4–61.54) ng/mL and 5.4 (1.6–20.1) months, respectively. Median surgical time and hospital stay was 132 (75–313) min and 5.5 (4–13) days, respectively. After a mean follow-up of 29 (2–92) months, 3 patients died at 8, 14, and 40 months after salvage surgery, and 6 (18.75%) patients remain without biochemical relapse and further treatment. Median progression-free survival was 12 (1–81) months. In the univariable Cox regression analysis, age at time of surgery, preoperative PSA, and the time from primary treatment to salvage surgery were identified as significant parameters for biochemical relapse. Only the interval from primary to salvage surgery was significant in the multivariate analysis with a hazard ratio of 1.008 (95% CI: 1.001–1.015, p = 0.018). In the entire cohort, 4 adjunctive surgeries (3 ureteroneocystostomies and 1 nephrectomy) were needed due to local progressive disease. Conclusion: Seminal vesicle resection is feasible with no significant intra- or postoperative complications. Almost all patients progressed to biochemical or systemic relapse. Salvage surgery must be seen as a preventive for local symptoms, in our experience most often postrenal ipsilateral obstruction.
Epidemiology of COVID-19 Infection in Hospitalized End-Stage Kidney Disease Patients in a Predominantly African-American Population
Authors: Navarrete José E. , Tong David C. , Cobb Jason , Rahbari-Oskoui Frederic F. , Hosein Darya , Caberto Sheryl C. , Lea Janice P. , Franch Harold A.
Published: April 2021

Background: End-stage kidney disease patients on dialysis are particularly susceptible to COVID-19 infection due to comorbidities, age, and logistic constraints of dialysis making social distancing difficult. We describe our experience with hospitalized dialysis patients with COVID-19 and factors associated with mortality. Methods: From March 1, 2020, to May 31, 2020, all dialysis patients admitted to 4 Emory Hospitals and tested for COVID-19 were identified. Sociodemographic information and clinical and laboratory data were obtained from the medical record. Death was defined as an in-hospital death or transfer to hospice for end-of-life care. Patients were followed until discharge or death. Results: Sixty-four dialysis patients with COVID-19 were identified. Eighty-four percent were African-American. The median age was 64 years, and 59% were males. Four patients were on peritoneal dialysis, and 60 were on hemodialysis for a median time of 3.8 years, while 31% were obese. Fever (72%), cough (61%), and diarrhea (22%) were the most common symptoms at presentation. Thirty-three percent required admission to intensive care unit, and 23% required mechanical ventilation. The median length of stay was 10 days, while 11 patients (17%) died during hospitalization and 17% were discharged to a temporary rehabilitation facility. Age >65 years (RR 13.7, CI: 1.9–100.7), C-reactive protein >100 mg/dL (RR 8.3, CI: 1.1–60.4), peak D-dimer >3,000 ng/mL (RR 4.3, CI: 1.03–18.2), bilirubin >1 mg/dL (RR 3.9, CI: 1.5–10.4), and history of peripheral vascular disease (RR 3.2, CI: 1.2–9.1) were associated with mortality. Dialysis COVID-19-infected patients were more likely to develop thromboembolic complications than those without COVID-19 (RR 3.7, CI: 1.3–10.1). Conclusion: In a predominantly African-American population, the mortality of end-stage kidney disease patients admitted with COVID-19 infection was 17%. Age, C-reactive protein, D-dimer, bilirubin, and history of peripheral vascular disease were associated with worse survival.
Different Types of Auricular Keloids and Treatment by Intralesional Cryosurgery: Best Practice for Obtaining Long-Lasting Clinical Results
Authors: Har-Shai Yaron , Har-Shai Lior , Zouboulis Viktor A. , Zouboulis Christos C.
Published: April 2021

Background: Auricular keloids belong to the most perplexing medical conditions, which have significant psychosocial impact on the patient’s body image and quality of life. Summary: The article is purposed to provide dermatologists and plastic surgeons with the best proven practice using intralesional cryosurgery for the treatment of the different auricular keloid types in order to obtain superior clinical results by minimizing the probability of recurrence. In the past 20 years, the authors have developed novel procedures in order to increase the effectiveness of intralesional cryosurgery on auricular keloids, including hydrodissection, warm gauze technique, and excision of dangling skin. Long-lasting clinical results with a low recurrence rate and a satisfactory aesthetic outcome are achieved with no deformation of the ear framework.
Putative Anti-Immobility Action of Acute Insulin Is Attributable to an Increase in Locomotor Activity in Healthy Wistar Rats
Authors: Gutiérrez-García Ana G. , Contreras Carlos M.
Published: April 2021

Background/Aims: Anti-immobility actions of insulin in diabetic rats that are subjected to the forced swim test (FST) have been reported. In this test, low doses of antidepressants exert actions after long-term treatment, without affecting locomotor activity in healthy rats. Few studies have compared acute and chronic actions of insulin with antidepressants in healthy rats. Methods: We hypothesized that if insulin exerts a true anti-immobility action, then its effects must be comparable to fluoxetine in both a 1-day treatment regimen and a 21-day treatment regimen in healthy, gonadally intact female Wistar rats. Results: The results showed that low levels of glycemia were produced by all treatments, including fluoxetine, and glycemia was lower in proestrus-estrus than in diestrus-metestrus. None of the treatments or regimens produced actions on indicators of anxiety in the elevated plus maze. Insulin in the 1-day regimen increased the number of crossings and rearings in the open field test and caused a low cumulative immobility time in the FST. These actions disappeared in the 21-day regimen. Compared with the other treatments, fluoxetine treatment alone or combined with insulin produced a longer latency to the first period of immobility and a shorter immobility time in the chronic regimen in the FST, without affecting locomotor activity, and more pronounced actions were observed in proestrus-estrus (i.e., a true anti-immobility effect). Conclusion: These results indicate that insulin does not produce a true antidepressant action in healthy rats. The purported antidepressant effects that were observed were instead attributable to an increase in locomotor activity only in the 1-day regimen.
Effect of Bias Gas Flow on Tracheal Cytokine Concentrations in Ventilated Extremely Preterm Infants: A Randomized Controlled Trial
Authors: Bach Katinka P. , Kuschel Carl A. , Patterson Nicola , Skwish Hana , Huth Sabine , Phua Hui Hui , Bloomfield Frank H.
Published: April 2021

Background: The objective of this study was to determine whether ventilator bias gas flow affects tracheal aspirate (TA) cytokine concentrations in ventilated extremely preterm infants. Methods: This is a randomized controlled trial in a tertiary neonatal unit in New Zealand. Preterm infants (<28 weeks’ gestation/<1,000 g) requiring intubation in the first 7 days after birth were randomized to bias gas flows of 4 or 10 L/min. Cytokine concentrations in TA and plasma were measured at 24, 72, and 120 h after the onset of ventilation. The primary outcome measure was concentration of interleukin (IL)-8 in TA 24 h after the onset of mechanical ventilation. Results: Baseline demographics were similar in babies randomized to 4 (n = 50) and 10 (n = 45) L/min bias gas flow. TA IL-8 concentrations were not different between groups. Plasma IL-8 concentrations decreased over time (p < 0.05). Respiratory support and incidence of bronchopulmonary dysplasia at 36 weeks’ corrected gestational age were similar between groups. Fewer babies ventilated at 4 L/min developed necrotizing enterocolitis (NEC) ≥ stage 2 (n = 0 vs. n = 5; p = 0.02) and fewer died (n = 1 vs. n = 5, p = 0.06). Conclusions: Lower bias gas flow in ventilated extremely preterm infants did not alter TA cytokine concentrations but the lower incidence of NEC and mortality warrants further investigation.
Revising the Maximal Contrast Dose for Predicting Acute Kidney Injury following Coronary Intervention
Authors: Hattar Laith , Assaker Jean-Pierre , Aoun Joe , Price Lori Lyn , Carrozza Joseph , Jaber Bertrand L.
Published: April 2021

Introduction: The maximal allowable contrast dose (MACD = 5 × body weight/serum creatinine) is an empiric equation that has been used and validated in several studies to mitigate the risk of contrast-induced acute kidney injury (CI-AKI). However, coefficient 5 (referred to as factor K) was empirically devised and never disputed. The aim of this study was to refine the MACD equation for the prediction of CI-AKI following percutaneous coronary interventions (PCIs). Methods: This is a single-center, retrospective cohort study of adults undergoing PCI. Electronic medical records were reviewed to identify patients who underwent PCI between 2010 and 2019, derived from the National Cardiovascular Data Registry Cath-PCI registry for our hospital. Factor K (defined as contrast volume × serum creatinine/body weight) was calculated for every patient. A receiver operating characteristic (ROC) curve was constructed, and the Youden index was used to identify the optimal cut-off value for factor K in predicting severe (stages 2–3) CI-AKI. Results: Of the 3,506 patients undergoing PCI, 255 (7.2%) developed CI-AKI, and 68 (26.7%) of the 255 experienced severe AKI. Factor K predicted all-stage CI-AKI (area under the ROC curve 0.649; 95% CI 0.611, 0.686) but had better performance for predicting severe (stages 2–3) AKI (0.736; 95% CI 0.674, 0.800). The optimal cut-off value for factor K in predicting severe CI-AKI was 2.5, with a corresponding sensitivity of 68.7% and specificity of 70.5%. On subgroup analyses, optimal cut-off values for factor K for high-risk groups were not significantly different from those of low-risk groups. Conclusion: Our study indicates that factor K in the MACD equation is an independent risk factor for the development of severe CI-AKI, with an optimal cut-off value of 2.5. If our findings are validated, the MACD equation should be revised to incorporate the coefficient of 2.5 instead of 5.