bluuebunny/crossref_metadata_2025 huggingface dataset:
Presence of Gram‐negative bacteria and Staphylococcus aureus on the skin of blood donors in the Democratic Republic of the Congo
Authors: Heroes Anne‐Sophie , Okitale Patient , Ndalingosu Natacha , Vandekerckhove Philippe , Lunguya Octavie , Jacobs Jan
Published: December 2022

Background

Skin bacteria may contaminate blood products but few data are available on sub‐Saharan Africa (sSA). We assessed the presence of Gram‐negative bacteria and Staphylococcus aureus on blood donor skin and evaluated skin antisepsis in the Democratic Republic of the Congo (DRC).

Study Design and Methods

Among blood donors at the National Blood Transfusion Center (NBTC) and at a rural hospital, the antecubital fossa skin of the non‐disinfected arm (not used for blood collection) was swabbed (25cm2 surface) and cultured for total and Gram‐negative bacterial counts. Bacteria were identified with MALDI‐TOF and tested for antibiotic susceptibility by disk diffusion. For evaluation of the NBTC antisepsis procedure (i.e., ethanol 70%), the culture results of the disinfected arm (used for blood collection) were compared with those of the non‐disinfected arm.

Results

Median total bacterial counts on 161 studied non‐disinfected arms were 1065 Colony‐Forming Units (CFU) per 25 cm2, with 43.8% (70/160) of blood donors growing Gram‐negative bacteria and 3.8% (6/159) Staphylococcus aureus (2/6 methicillin‐resistant). Non‐fermentative Gram‐negative rods predominated (74/93 isolates, majority Pseudomonas spp., Acinetobacter spp.). Enterobacterales comprised 19/93 isolates (mostly Pantoea spp. and Enterobacter spp.), 5/19 were multidrug‐resistant. In only two cases (1.9%, 2/108) the NBTC antisepsis procedure met the acceptance criterion of ≤2 CFU/25 cm2.

Conclusion

Skin bacterial counts and species among blood donors in DRC were similar to previously studied Caucasian populations, including cold‐tolerating species and bacteria previously described in transfusion reactions. Prevention of contamination (e.g., antisepsis) needs further evaluation and customization to sSA.
Prevalence of incidental humeral intracondylar fissures in brachycephalic breed dogs in CT studies
Authors: Franklin Chantelle , Herrtage Michael , Harris Karen , Genain Marie‐Aude
Published: December 2022

Humeral intracondylar fissures (HIF) have been predominantly reported in spaniel breeds and proposed to be possible risk factors for humeral condyle fractures (HCF). We hypothesized that the prevalence of incidental HIF in French Bulldogs may be greater than that of other brachycephalic breeds. A retrospective, observational, prevalence study was performed using CT examinations of French bulldogs and other brachycephalic breed dogs presenting for an unrelated condition. Two European College of Veterinary Diagnostic and Imaging‐certified radiologists reviewed the images of the humeral condyles of these dogs. A classification system was devised to grade the findings. We considered a Score 1 to be normal, Score 2 to have centralised sclerosis, Score 3 to have a partial fissure and Score 4 to have a complete fissure. A total of 228 elbows were reviewed from 122 dogs. Of this population, 145 elbows were from French Bulldogs, 54 were from Pugs, and the remainder were from a mix of other brachycephalic breeds. The prevalence of HIF (score 3 or 4) in elbows of the French bulldog, pug and other breed groups was 6.9% (CI 2.8–11%), 5.6% (CI 0–11.7%), and 3.4% (CI 0–10.15%), respectively. At a dog level, the prevalence of HIF (score 3 or 4 present in at least one elbow) was found to be 11.8% (CI 4.6–19%) in French Bulldogs, 11.1% (CI 0–22.9%) in Pugs, and 5.26% (CI 0–15%) in the other breed group. There was no significant difference between the breed groups. The inter‐reviewer reliability for CT scoring of HIF based on Cohen's weighted kappa was low at 0.19.
Reliability of State-of-Health of the Flexible Li-Ion Batteries Under Various Flexing Conditions and Calendar Aging
Authors: Lall Pradeep , Jang Hyesoo
Published: December 2022

Due to the necessity for flexibility without compromising the Li-ion battery (LIB) state of health (SOH), LIB is a critical challenge for flexible hybrid electronic (FHE) devices. A thin form factor-based LIB with a thickness of less than 1 mm is regarded as the candidate material to suit such demands since it can be folded, bent, and twisted with minimal performance loss. Furthermore, LIB has high specific power (W/Kg) and specific energy (Wh/Kg), as well as a smaller memory effect, making it more appealing for wearable applications. While much research has been done on the chemo-physical effects of repeated charging and discharging LIB, such as solid electrolyte interphase (SEI) development, material deterioration, and so on, but such impacts owing to repeated flexure LIB have not been much studied. The deterioration of the reliability of thin-flexible power sources was investigated in this work under twist, flexing, and flex-to-install to simulate stresses of daily motions of the human body by utilizing motion-control setups in a lab setting. Furthermore, an AI-based regression model has been developed to forecast the SOH of the battery based on many variables such as physical, atmospheric, and chemo-mechanical experimental circumstances that may be difficult to address by manpower. Based on the various variables and their interactions, the generated models are expected to be used to predict battery life and assess the acceleration factors between test circumstances and usage conditions for a range of test scenarios.
Predictions of Airside Economization-Based Air-Cooled Data Center Environmental Burden Reduction
Authors: Chen Li , Wemhoff Aaron P.
Published: December 2022

Modern data centers, which consume roughly 3% of global electricity, continue to experience increased demand. Therefore, green data centers that consume less energy and have minimal environmental impact are desirable. This study examines the potential energy savings and environmental benefits of applying airside economization with evaporative cooling in air-cooled data centers in the continental U.S. A generic data center that employs a Computer Room Air Conditioning (CRAC)-based cooling system with a total IT load of 400 kW is modeled at 925 locations using the National Renewable Energy Laboratory’s (NREL’s) TMY3 database. The energy savings and environmental benefits are evaluated in terms of key data center performance metrics: Power Usage Effectiveness (PUE), Carbon Usage Effectiveness (CUE), and the recently proposed Water Scarcity Usage Effectiveness (WSUE) metric, which quantifies the holistic impact of water consumption on regional water availability. Results are aggregated and analyzed at the U.S. State level. It is found that airside economization implementation in the continental U.S. is feasible 6.57% and 21.5% of the year on average based on ASHRAE recommended and allowable envelopes, respectively. Furthermore, results indicate that carbon footprint and water scarcity footprint can be reduced by up to 16% when economization is implemented based on the ASHRAE allowable envelope.
A Study on Parameters That Impact the Thermal Fatigue Life of BGA Solder Joints
Authors: Arun Deo Karthik , Kono Raymond-Noel , Cai Chongyang , Yang Junbo , Lai Yangyang , Park Seungbae
Published: December 2022

Estimation of the thermal fatigue life of solder joints and identification of parameters that enhance the fatigue life are important steps in the development stage of BGA packages. In this study, different parameters of Sn-Ag-Cu 305 BGA (Ball Grid Array) solder balls are investigated to understand their impact on the number of cycles to failure under thermal fatigue life tests. Initially, accelerated thermal cycling fatigue tests on two electronic packages were conducted by three different vendors and it was observed that the results were significantly different. The first part of this study dwells into understanding the influence of parameters such as the solder mask design; SMD and NSMD, the variation in the solder ball geometry, copper pad thickness and diameter and material properties of the PCB on the accelerated thermal cycling performance of the BGA packages. The later part deals with understanding the root cause for the variation in the estimated life of two BGA packages by the three different vendors.
Thermal Optimization of a Silicon Carbide, Half-Bridge Power Module
Authors: Moreno Gilberto , Major Joshua , DeVoto Douglas , Khan Faisal , Narumanchi Sreekant , Feng Xuhui , Paret Paul
Published: December 2022

This project describes the modeling process to design the packaging and heat exchanger for a half-bridge wide-bandgap (WBG) power semiconductor module. The module uses two silicon carbide, metal-oxide-semiconductor field-effect transistor (MOSFET) devices per switch position that are soldered to an aluminum nitride, direct-bond copper (DBC) substrate. A baseplate cooling configuration (e.g., no thermal grease) is used along with a water-ethylene glycol, jet-impingement-style heat exchanger. The heat exchanger was designed to be fabricated using prototyping equipment from the National Renewable Energy Laboratory, complies with automotive standards (for minimal channel sizes, flow rates, and coolant), and considers reliability aspects (i.e., erosion/corrosion). Device-scale computational fluid dynamics (CFD) is used first to design the slot jet impingement cooling configuration and compute the effective heat transfer coefficient (HTC) of the concept. The computed HTCs are then used as boundary conditions for a finite element study to optimize the package geometry (e.g., device layout and baseplate thickness) to minimize thermal resistance and minimize temperature variation between the module’s four devices. Finally, a fluid manifold is designed to generate the slot jets and cool the devices. Module-scale CFD predicts a relatively low junction-to-fluid thermal resistance of 16.7 mm2·K/W, a 1.4°C temperature variation between devices, and a total pressure drop of 5,860 Pa (0.85 psi) for the design. The thermal resistance of the module design is about 67% lower than the 2015 BMW i3 power electronics/modules thermal resistance.
Thermomechanical Reliability of BGA Packages With Different Underfill Reinforcement Methods
Authors: Lai Yangyang , Cai Chongyang , Pan Ke , Yang Junbo , Ha Jonghwan , Yin Pengcheng , Deo Karthik , Park Seungbae
Published: December 2022

In this paper, an experimental approach is presented to investigate the influence of second level underfill on the thermomechanical behavior of two BGA packages during thermal cycles. Two different flip chip packages with two major underfill reinforcement methods (corner bonding and full bottom surface bonding) and no-underfill were studied. To quantitatively measure the deformation of solder balls, all the BGA packages were cross-sectioned before thermal cycles. The two-dimensional digital image correlation (DIC) technique was used to capture the in-plane deformation of the critical solder ball in thermal cycling intervals. The accumulated plastic strain of the BGA solder was calculated after every 10 thermal cycles. The temperature of each cycle was set from −40 to 100 °C at a 20°C/second rate. The experiment results showed that Package A with fully underfilled and corner underfilled both alleviated the averaged plastic strain on the critical solder ball in comparison with the no-underfilled Package A. However, Package B with corners underfilled had a larger plastic strain than the package without underfill. The material properties of underfill applied in the two reinforcement methods are identical. The results indicate that inappropriate underfilling methods can adversely affect the thermomechanical reliability of the packages. The underfill material and reinforcement methods are associated with the stiffness rigidity and the compact CTE of the package itself. In the respect of thermomechanical reliability, second level underfilling should be individually specified for varied packages.
Length-Scale Effects in Average Viscoplastic Behavior of Sintered Silver Materials: Empirical Exploration With Indentation Methods
Authors: Leslie David , Dasgupta Abhijit , Damian Andrei
Published: December 2022

Sintered silver materials (with and without epoxy matrices) are used in microelectronics, as high-temperature interconnect materials, and also as conductor trace materials in printed electronic circuitry. The sintering process results in an interconnected assemblage of discrete agglomerated particles. This results in intrinsic length-scale effects under the action of different stress gradients. In other words, the effective homogenized average continuum-scale material behavior changes with the local magnitude of the stress gradients. Consequently, regions of sharp, localized stress concentrations have to be modeled with different effective continuum material properties, compared with the properties that are relevant for regions that have a uniform stress field. In this study, the focus in on the effective creep behavior, in particular. This length-scale effect is empirically explored in this study using nanoindentation with indenters of different tip radii, causing different stress gradients. Properties estimated by each indenter are compared to demonstrate the dependence of the effective continuum properties on the local length scale effects (generated by the ratio of the tip radius to the characteristic discrete dimension of the sintered particles).
ANN Based Assessment of State-of-Health Reliability of Flexible Li-Ion Batteries Under Dynamic Flexing and Calendar Aging
Authors: Lall Pradeep , Jang Hyesoo
Published: December 2022

Wearable electronics have garnered much attention owing to benefits such as closer integration of form with function, flexibility, and light-weighting. Power sources used with FHE may be subject to dynamic flexing in addition to flex-to-install during the usage life of the product. While thick block batteries have been studied extensively in prior research — the impact of stresses of daily motion on the state of health degradation of thin-flexible batteries in conjunction with the use parameters is not well understood. Use conditions, including storage duration, operating temperature, flexing frequency, interval, and flex radius, might vary. Machine learning (ML) methods are needed prediction of state-of-health (SOH) degradation of the battery in various environmental conditions. It is not cost-effective to measure battery response in every condition, while the ANN ML might be able to assess conditions not previously measured. In this regard, it is expected that the ANN might be able to train the simulation. In this study, the simulation of SOH degradation on charging/discharging the flexible battery in dynamic folding, twisting and static folding with a calendar-aged battery in high temperature have been conducted. Accordingly, the ANN ML model has been trained with the simulation datasets to substitute the simulation. The generated data will be used for cross-validation of ML model and simulation for the battery life prediction. There is an expectation that such a combined method for data analysis might be helpful for time efficiency and cost reduction of research.
Characterization and Reliability Analysis of Direct-Write Additively Printed Flexible Humidity Sensor With Super Capacitive Material for Wearable Astronaut Sensor in Harsh Environments
Authors: Lall Pradeep , Jang Hyesoo , Hill Curtis
Published: December 2022

Using additive technologies to fabricate printed circuit boards eliminates the need for expensive manufacturing - software-based design and production permit production flexibility, as well as quicker tool modifications and design evolution. In addition, additive printing techniques can be applied to various surfaces and shapes. This adaptability to a wide range of applications enables the construction of novel applications, such as biosensors, by designers. Several previous studies have focused on developing additively printed humidity sensors because of their potential for flexibility and integration. Flexure in the operating environment has been known to cause performance degradation in prior generations of temperature and humidity sensor technologies. This study uses the direct write printing method with a nScrypt printer to print the humidity sensor. Characterization of the sensor has been done by studying the process-performance interactions of temperature coefficient to resistance and sensitivity to humidity. Sensor accuracy, hysteresis, repeatability, linearity, and stability have been quantified concerning printing recipe and encapsulation. A folding reliability test has been conducted to assess the viability of the sensor in operation to mimic real-life use conditions. The cyclic folding motions are administered every 13 seconds with the same folding diameter and travel distance on every three samples, with single trace and multi-trace sensing materials and trace with polyimide encapsulation. Furthermore, chemo-electrical measurement with cyclic voltammetry method has been conducted to assess water possession under high humidity conditions. It is found that encapsulation might help improve the humid and mechanical reliability of the additively printed humidity sensor.
A Control Strategy for Minimizing Temperature Fluctuations in High Power Liquid to Liquid CDUs Operated at Very Low Heat Loads
Authors: Heydari Ali , Shahi Pardeep , Radmard Vahideh , Eslami Bahareh , Chowdhury Uschas , Hinge Chandraprakash , Reddy Cinthaparthy Lochan Sai , Miyamura Harold , Modi Himanshu , Agonafer Dereje , Rodriguez Jeremy
Published: December 2022

The rising demand for high-performance central and graphical processing units has resulted in the need for more efficient thermal management techniques like direct-to-chip liquid cooling. Direct Liquid Cooling using cold plates is one of the most efficient and investigated cooling technologies since the 1980s. Major data and cloud providers are actively deploying liquid-cooled data center infrastructure due to rising computational demands. Liquid to liquid heat exchangers used in liquid-cooled data centers is also referred to as coolant distribution units (CDUs). Most of these CDUs selected by the data center operator is based on the heat load of the data center and the available head with that CDU. In this study, three 52U racks with six high-power TTV-based servers (Thermal Test Vehicles) in each rack were designed and deployed. Each server consists of eight GPU TTVs and six NV switch heaters. A 450-kW liquid-cooled CDU is used, and propylene glycol 25% is used as a coolant. Typical CDUs are designed to operate at 20 to 30% of the rated heat load to achieve a stable secondary coolant supply temperature. The present study will investigate the operations of CDU at very low heat loads, like 1% to 10% of the CDU’s rated capacity. At these low loads, large fluctuations in secondary side supply temperature were observed. This large fluctuation can lead to the failure of the 3-way valve used in CDUs at the primary side. In this paper, a control strategy is developed to stabilize the secondary supply temperature within ± 0.5 °C at very low loads using the combination of a flow control valve on the primary side and PID control settings within the CDU.
Transient CFD Analysis of Dynamic Liquid-Cooling Implementation at Rack Level
Authors: Modi Himanshu , Shahi Pardeep , Sivakumar Akiilessh , Saini Satyam , Bansode Pratik , Shalom Vibin , Rachakonda Amrutha Valli , Gupta Gautam , Agonafer Dereje
Published: December 2022

Direct to chip liquid-cooling technique has been widely implemented for the cooling of processors with high thermal design power. To further enhance the efficiency of liquid cooling, ongoing research focuses on the optimizations at the cold plate level or by changing the flow configurations. But in all cases, the coolant which is pumped across the rack is pumped at a constant flow rate irrespective of the workload utilization at the individual server, resulting in excess pumping of coolant. A practical approach is to dynamically vary the flow rate to each server as per server workload utilization. In this study, transient analysis is performed by varying the flow rate across individual servers at rack level using CFD. A CFD model mimicking four servers placed at different heights on a standard 42U rack is developed. The flow variation through each of the servers is done using a damper arrangement representing a flow control device. A controller is integrated to automate the process of opening and closing of FCD to vary the flow based on the average outlet temperature from each server. A baseline simulation with all servers running at maximum power dissipation with a constant coolant flow rate is compared with cases where the coolant flow rate is controlled dynamically for varying thermal design power (TDP). The results shown analyze the impact of the dynamic response of the flow control device on transient thermal and hydraulic characteristics across the rack is done.
Power Usage Effectiveness Analysis of a High-Density Air-Liquid Hybrid Cooled Data Center
Authors: Heydari Ali , Eslami Bahareh , Radmard Vahideh , Rebarber Fred , Buell Tyler , Gray Kevin , Sather Sam , Rodriguez Jeremy
Published: December 2022

Environmental impacts of ever-growing computational requirements have raised worldwide concerns and significant efforts have been dedicated to reducing power consumption, water usage, and eventually the carbon footprint. Cloud architecture and services have undergone substantial development to become more sustainable and reliable with implementing advanced cooling solutions. In this research, a bottom-up approach has been presented to investigate the energy optimization opportunities of an air-liquid hybrid cooling method compared to the pure air cooling for a 1.7 MW data center. A gradual transition from 100% air cooling to 25%–75% air and liquid cooling has been studied to capture the changes in IT, fan, facility, and the total data center power consumption. Various system design optimizations such as supply air temperature (SAT), facility chiller water temperature, economization and secondary fluid temperature are embedded in this work to highlight the importance of proper setpoint conditions on both primary and secondary sides. Computational fluid dynamics (CFD) and flow network modeling (FNM) are utilized to precisely assess the performance of air and liquid cooling by evaluating the required flow rate, pressure drop, and critical case temperature of computing components as well as temperature change of cooling medium. Energy consumption of the selected cooling equipment is measured based on the BIN data for CRAH and CDU’s performance models. Power usage effectiveness (PUE) measured and compared with Total Usage Effectiveness (TUE) which appears to be a more suitable metric to weigh a data center’s design efficiency by not limiting the fan power to the IT boundary. For the most optimized case, we obtained up to 27% lower consumption in the facility power and 15.5% lower usage in the whole data center site. Increasing the percentage of liquid cooling contribution significantly diminishes the power intake which addresses concerns about natural resources limit as one of the most critical requirements of a sustainable design.
SOH Degradation Estimation of Thin Flexible Li-Ion Power Sources Subjected to Accelerated Life Cycling With Randomized Charge-Discharge and C-Rates
Authors: Lall Pradeep , Soni Ved
Published: December 2022

The growing need for wearable devices, fitness accessories, and biomedical equipment has led to the upsurge in research and development of thin, flexible battery research and development. Studying degradation of such power sources used in consumer electronics devices is essential from multiple perspectives, as it allows the manufacturer to determine device warranty, affects the user purchasing decision, and can also be used to inform the user of their device’s battery health and remaining useful life in real-time. In order to achieve these goals via empirical methods, batteries are generally subjected to accelerated life cycling tests with various operating conditions, and their degradation data gathered is then used to model their SOH degradation. However, in the real world, the charge-discharge depth and charge-discharge rates for every cycle are hardly constant and vary greatly for the same user over time and for different users who use their devices differently. The real task for such developed battery models is to estimate the SOH of batteries being used in real-world scenarios with such random variations of charge-discharge depth and C-rates. To this end, the current work conducts accelerated life cycling tests of batteries with random variation in these two parameters, individually and simultaneously. Finally, multiple iterations of the SOH estimation models have been presented with different predictor variables to minimize the model validation error.
Experimental Probing of the Bias Dependent Self-Heating in AlGaN/GaN HEMTs With a Transparent Indium Tin Oxide Gate
Authors: Karim Anwarul , Kim Tae Kyoung , Shoemaker Daniel , Song Yiwen , Kwak Joon Seop , Choi Sukwon
Published: December 2022

The demand for high power and high-frequency radio frequency (RF) power amplifiers makes AlGaN/GaN high electron mobility transistors (HEMTs) an attractive option due to their large critical field, high saturation velocity, and reduced device footprint as compared to Si-based counterparts. However, due to the high operating power densities, intense device self-heating occurs, which degrades the electrical performance and compromises the device’s reliability. The self-heating behavior of AlGaN/GaN HEMTs is known to be not solely a function of the dissipated power but is highly bias-dependent. As the operation of RF power amplifiers involves alteration of the device operation from fully-open to pinched-off channel conditions, it is critical to experimentally map the full channel temperature profile as a function of bias conditions. However, such measurement is difficult using optical thermography techniques due to the lack of optical access underneath the gate electrode, where the peak temperature is expected to occur.

To address this challenge, an AlGaN/GaN HEMT employing a transparent gate made of indium tin oxide (ITO) was fabricated, which enables full channel temperature mapping using Raman spectroscopy. It was found that the maximum channel temperature rise under a partially pinched-off condition is more than ∼93% higher than that for an open channel condition, although both conditions would lead to an identical power dissipation level. The channel peak temperature probed in an ITO-gated device (underneath the gate) is ∼33% higher than the highest channel temperature that can be measured for a standard metal-gated AlGaN/GaN HEMT (i.e., next to the metal gate structure) operating under an identical bias condition. This indicates that one may significantly underestimate the device’s thermal resistance when solely relying on performing thermal characterization on the optically accessible region of a standard AlGaN/GaN HEMT. The outcomes of this study are important in terms of conducting a more accurate lifetime prediction of the device lifetime and designing thermal management solutions.
Nanosecond pulsed plasma discharge for remediation of simulated wastewater containing thiazine and azo dyes as model pollutants
Authors: Farooq Muhammad , Ismail Siddiqa , Rehman N. U.
Published: December 2022

Plasmas generated over and under the surface of water have immense scope for wastewater remediation due to in situ generation of redox-rich species. Remediation of simulated wastewater using underwater plasma discharge is reported in this paper. During the plasma discharge, an increase in energy coupling from source to discharge channel was noted with an increase in the applied pulsed DC voltage from 5 to 9kV. Higher energy coupling resulted in elevation of gas temperature and electron temperature. Concentrations of hydroxyl radicals and hydrogen peroxide, estimated spectrochemically in effluent water, also increased with the applied voltage. On the other hand, ozone concentration showed a decreasing trend with increasing applied voltage and the peak ozone density was obtained at the lower end of the applied voltage, i.e., at 5kV. With higher energy dissipation, a pronounced discharge and, hence, greater emission intensities of ultraviolet radiation, atomic oxygen, and atomic hydrogen were observed in discharge spectra. The oxidative-reductive stress produced by underwater discharge resulted in a degradation efficiency of 75.5% for methylene blue solution (thiazine dye) corresponding to energy yields of 3.55g/kWh. Similarly, the degradation efficiency of 81.4% for methyl orange solution (azo dye) with an energy yield of 4.73g/kWh was achieved with this discharge. From the considerations of collision theory, activation energies of 67.17kJ/mol for methylene blue and 75.32kJ/mol for methyl orange degradation were estimated for the plasma discharge. Fourier-transform infrared spectroscopy was utilized to further reveal the possible effects of plasma therapy on different bonds of the dyes. Additionally, gas chromatography mass spectrometry analyses were used to suggest the possible degradation pathways of the two dyes. Instant dye degradation in flowing samples was compared with contemporary dye degradation results listed in literature to show the effectiveness of the used technique.
Differentiating interactions of antimicrobials with Gram-negative and Gram-positive bacterial cell walls using molecular dynamics simulations
Authors: Vaiwala Rakesh , Sharma Pradyumn , Ganapathy Ayappa K.
Published: December 2022

Developing molecular models to capture the complex physicochemical architecture of the bacterial cell wall and to study the interaction with antibacterial molecules is an important aspect of assessing and developing novel antimicrobial molecules. We carried out molecular dynamics simulations using an atomistic model of peptidoglycan to represent the architecture for Gram-positive S. aureus. The model is developed to capture various structural features of the Staphylococcal cell wall, such as the peptide orientation, area per disaccharide, glycan length distribution, cross-linking, and pore size. A comparison of the cell wall density and electrostatic potentials is made with a previously developed cell wall model of Gram-negative bacteria, E. coli, and properties for both single and multilayered structures of the Staphylococcal cell wall are studied. We investigated the interactions of the antimicrobial peptide melittin with peptidoglycan structures. The depth of melittin binding to peptidoglycan is more pronounced in E. coli than in S. aureus, and consequently, melittin has greater contacts with glycan units of E. coli. Contacts of melittin with the amino acids of peptidoglycan are comparable across both the strains, and the D-Ala residues, which are sites for transpeptidation, show enhanced interactions with melittin. A low energetic barrier is observed for translocation of a naturally occurring antimicrobial thymol with the four-layered peptidoglycan model. The molecular model developed for Gram-positive peptidoglycan allows us to compare and contrast the cell wall penetrating properties with Gram-negative strains and assess for the first time binding and translocation of antimicrobial molecules for Gram-positive cell walls.
Role Model or Quitter? Social Media’s Response to Simone Biles at Tokyo 2020
Authors: Doehler Steph
Published: December 2022

During the Tokyo 2020 Olympics, Team USA athlete Simone Biles withdrew from several gymnastics events midcompetition, citing mental health issues. Biles, one of the most recognizable stars of the Games, faced intense scrutiny from both the world’s media and the general public in the immediate aftermath. The purpose of this study was to analyze the Facebook narrative surrounding Biles’s withdrawal within the theoretical context of framing, as crafted through user comments on various public high-profile Facebook pages. A total of 87,714 user comments were collected and analyzed using the qualitative software Leximancer. The themes emerging from the data suggested a polarizing narrative, with many users supporting Biles, engaging in the wider discussion surrounding athlete mental health, while others condemned her action, suggesting she quit on the biggest sporting stage.
Stomatal CO
2
/bicarbonate sensor consists of two interacting protein kinases, Raf-like HT1 and non-kinase-activity requiring MPK12/MPK4
Authors: Takahashi Yohei , Bosmans Krystal C. , Hsu Po-Kai , Paul Karnelia , Seitz Christian , Yeh Chung-Yueh , Wang Yuh-Shuh , Yarmolinsky Dmitry , Sierla Maija , Vahisalu Triin , Waszczak Cezary , McCammon J. Andrew , Kangasjärvi Jaakko , Zhang Li , Kollist Hannes , Trac Thien , Schroeder Julian I.
Published: December 2022

The continuing rise in the atmospheric carbon dioxide (CO
2
) concentration causes stomatal closing, thus critically affecting transpirational water loss, photosynthesis, and plant growth. However, the primary CO
2
sensor remains unknown. Here, we show that elevated CO
2
triggers interaction of the MAP kinases MPK4/MPK12 with the HT1 protein kinase, thus inhibiting HT1 kinase activity. At low CO
2
, HT1 phosphorylates and activates the downstream negatively regulating CBC1 kinase. Physiologically relevant HT1-mediated phosphorylation sites in CBC1 are identified. In a genetic screen, we identify dominant active HT1 mutants that cause insensitivity to elevated CO
2
. Dominant HT1 mutants abrogate the CO
2
/bicarbonate-induced MPK4/12-HT1 interaction and HT1 inhibition, which may be explained by a structural AlphaFold2- and Gaussian-accelerated dynamics-generated model. Unexpectedly, MAP kinase activity is not required for CO
2
sensor function and CO
2
-triggered HT1 inhibition and stomatal closing. The presented findings reveal that MPK4/12 and HT1 together constitute the long-sought primary stomatal CO
2
/bicarbonate sensor upstream of the CBC1 kinase in plants.
High-resolution cryo-EM structure of the
Shigella
virus Sf6 genome delivery tail machine
Authors: Li Fenglin , Hou Chun-Feng David , Yang Ruoyu , Whitehead Richard , Teschke Carolyn M. , Cingolani Gino
Published: December 2022

Sf6 is a bacterial virus that infects the human pathogen
Shigella flexneri.
Here, we describe the cryo–electron microscopy structure of the Sf6 tail machine before DNA ejection, which we determined at a 2.7-angstrom resolution. We built de novo structures of all tail components and resolved four symmetry-mismatched interfaces. Unexpectedly, we found that the tail exists in two conformations, rotated by ~6° with respect to the capsid. The two tail conformers are identical in structure but differ solely in how the portal and head-to-tail adaptor carboxyl termini bond with the capsid at the fivefold vertex, similar to a diamond held over a five-pronged ring in two nonidentical states. Thus, in the mature Sf6 tail, the portal structure does not morph locally to accommodate the symmetry mismatch but exists in two energetic minima rotated by a discrete angle. We propose that the design principles of the Sf6 tail are conserved across P22-like Podoviridae.
Optogenetic polymerization and assembly of electrically functional polymers for modulation of single-neuron excitability
Authors: Sessler Chanan D. , Zhou Yiming , Wang Wenbo , Hartley Nolan D. , Fu Zhanyan , Graykowski David , Sheng Morgan , Wang Xiao , Liu Jia
Published: December 2022

Ionic conductivity and membrane capacitance are two foundational parameters that govern neuron excitability. Conventional optogenetics has emerged as a powerful tool to temporarily manipulate membrane ionic conductivity in intact biological systems. However, no analogous method exists for precisely manipulating cell membrane capacitance to enable long-lasting modulation of neuronal excitability. Genetically targetable chemical assembly of conductive and insulating polymers can modulate cell membrane capacitance, but further development of this technique has been hindered by poor spatiotemporal control of the polymer deposition and cytotoxicity from the widely diffused peroxide. We address these issues by harnessing genetically targetable photosensitizer proteins to assemble electrically functional polymers in neurons with precise spatiotemporal control. Using whole-cell patch-clamp recordings, we demonstrate that this optogenetic polymerization can achieve stepwise modulation of both neuron membrane capacitance and intrinsic excitability. Furthermore, cytotoxicity can be limited by controlling light exposure, demonstrating a promising new method for precisely modulating cell excitability.
Loss of endothelial CFTR drives barrier failure and edema formation in lung infection and can be targeted by CFTR potentiation
Authors: Erfinanda Lasti , Zou Lin , Gutbier Birgitt , Kneller Laura , Weidenfeld Sarah , Michalick Laura , Lei Disi , Reppe Katrin , Teixeira Alves Luiz Gustavo , Schneider Bill , Zhang Qi , Li Caihong , Fatykhova Diana , Schneider Paul , Liedtke Wolfgang , Sohara Eisei , Mitchell Timothy J. , Gruber Achim D. , Hocke Andreas , Hippenstiel Stefan , Suttorp Norbert , Olschewski Andrea , Mall Marcus A. , Witzenrath Martin , Kuebler Wolfgang M.
Published: December 2022

Pneumonia is the most common cause of the acute respiratory distress syndrome (ARDS). Here, we identified loss of endothelial cystic fibrosis transmembrane conductance regulator (CFTR) as an important pathomechanism leading to lung barrier failure in pneumonia-induced ARDS. CFTR was down-regulated after
Streptococcus pneumoniae
infection ex vivo or in vivo in human or murine lung tissue, respectively. Analysis of isolated perfused rat lungs revealed that CFTR inhibition increased endothelial permeability in parallel with intracellular chloride ion and calcium ion concentrations ([Cl
−
]

i

and [Ca
2+
]

i

). Inhibition of the chloride ion–sensitive with-no-lysine kinase 1 (WNK1) protein with tyrphostin 47 or WNK463 replicated the effect of CFTR inhibition on endothelial permeability and endothelial [Ca
2+
]

i

, whereas WNK1 activation by temozolomide attenuated it. Endothelial [Ca
2+
]

i

transients and permeability in response to inhibition of either CFTR or WNK1 were prevented by inhibition of the cation channel transient receptor potential vanilloid 4 (TRPV4). Mice deficient in
Trpv4
(
Trpv4
−/−
) developed less lung edema and protein leak than their wild-type littermates after infection with
S. pneumoniae
. The CFTR potentiator ivacaftor prevented lung CFTR loss, edema, and protein leak after
S. pneumoniae
infection in wild-type mice. In conclusion, lung infection caused loss of CFTR that promoted lung edema formation through intracellular chloride ion accumulation, inhibition of WNK1, and subsequent disinhibition of TRPV4, resulting in endothelial calcium ion influx and vascular barrier failure. Ivacaftor prevented CFTR loss in the lungs of mice with pneumonia and may, therefore, represent a possible therapeutic strategy in people suffering from ARDS due to severe pneumonia.
Mutations in
troABCD
against Copper Overload in a
copA
Mutant of Streptococcus suis
Authors: Yang Xia , Peng Wei , Wang Yanna , Yan Kang , Liu Zewen , Gao Ting , Yang Keli , Liu Wei , Guo Rui , Li Chang , Chen Huanchun , Tian Yongxiang , Zhou Danna , Bei Weicheng , Yuan Fangyan
Published: December 2022

Metal homeostasis plays a critical role during the process of bacterial infection. We identified three important potential candidate genes involved in maintenance of intracellular copper homeostasis.
Conjunctival amelanotic melanoma presenting as a multifocal pink lesion
Authors: Kenworthy Matthew Keith , Kenworthy Sarah Jane , De Guzman Paolo , Morlet Nigel
Published: December 2022

Conjunctival amelanotic malignant melanoma is a rare form of melanoma, which lacks visible pigment and is commonly located underneath the eyelids in the bulbar conjunctiva. In this report, we described a case of a Caucasian women in her 70s who presented with unilateral irritation and tenderness following cataract surgery. On eversion of the eyelid, two elevated pink lesions were noted. Tumour - Node - Metastasis staging with the American Joint Committee on Cancer staging system eighth edition was T3C and required multiple excisions and reconstruction procedures. This case exemplified the diagnostic pitfall of conjunctival amelanotic malignant melanoma, which is a potentially life-threatening disease and the importance of histopathology in the diagnostic process.
Paraneoplastic syndrome due to angiomatoid fibrous histiocytoma: a known presentation of an uncommon diagnosis in a rare site and age
Authors: Or Omer , Olshinka Noam , Shussman Noam , Diment Judith
Published: December 2022

A woman in her 70s presented with a small subcutaneous retrosacrococcygeal mass and a history of elevated erythrocyte sedimentation rate present for several years. It was misdiagnosed as an inflammatory process of unclear origin. She underwent further investigation with the appearance of weight loss and weakness. A sacrococcygeal mass was noted on CT scan. A core needle biopsy was inconclusive for chordoma versus myoepithelioma. Wide surgical resection of the tumour including the coccygeal bone was performed. Following surgery, all the systemic symptoms resolved with normalisation of inflammatory markers. The pathological examination showed a relatively circumscribed multinodular myxoid tumour with lymphatic tissue cuff. Pan-sarcoma fusion analysis detected an EWSR1 (Exon7)-CREB1 (Exon7) fusion gene. The lesion was diagnosed as angiomatoid fibrous histiocytoma with paraneoplastic syndrome presentation of several years’ duration.
Strategies used by the soft drink industry to grow and sustain sales: a case-study of The Coca-Cola Company in East Asia
Authors: Huse Oliver , Reeve Erica , Bell Colin , Sacks Gary , Baker Phillip , Wood Benjamin , Backholer Kathryn
Published: December 2022

Background

The market and non-market activities of the food and beverage industry contribute to unhealthy and unsustainable dietary patterns, increasingly in low-income and middle-income countries (LMICs). We aimed to describe how The Coca-Cola Company (TCCC), as the world market leader in the sugar-sweetened beverage sector, operationalises their activities in LMICs in East Asia, among the world’s most highly populated yet under-researched countries, to illustrate the ways in which these activities may negatively influence health outcomes.

Methods

We adopted a theoretically-guided qualitative research design and documentary analysis method. Data sources included: industry documents and web pages, marketing case studies obtained from the World Advertising Research Centre, media reports, global trade summaries and websites of industry associations. To guide data analysis, we synthesised a conceptual framework from existing commercial determinants of health literature, to describe ways in which the market and non-market activities of TCCC influence health.

Results

TCCC leverages subsidiary companies and investments in international networks to expand its supply chains. The company engages in frequent political activities to minimise the implementation of nutrition policies that may impact profits. The company markets products, particularly on digital and mobile devices, often targeting children, adolescents and mothers, and undertakes public relations activities related to human rights, environmental sustainability and community and economic supports, and these public relations activities are often integrated into marketing campaigns. The identified activities of TCCC are frequently in direct contrast to efforts to improve the healthfulness of population diets in East Asia LMICs.

Conclusions

A public health analysis of the market and non-market activities of corporations active in unhealthy commodity industries needs to be broad in scope to cover the diverse set of strategies used to increase their market power and influence. Governments should consider a suite of policy options to attenuate these commercial determinants of unhealthy diets.
International variation in evidence-based emergency department management of bronchiolitis: a retrospective cohort study
Authors: Lirette Marie-Pier , Kuppermann Nathan , Finkelstein Yaron , Zemek Roger , Plint Amy C , Florin Todd Adam , Babl Franz E , Dalziel Stuart , Freedman Stephen , Roland Damian , Lyttle Mark David , Schnadower David , Steele Dale , Fernandes Ricardo M , Stephens Derek , Kharbanda Anupam , Johnson David W , Macias Charles , Benito Javier , Schuh Suzanne
Published: December 2022

Objectives

We aimed to evaluate the international variation in the use of evidence-based management (EBM) in bronchiolitis. We hypothesised that management consistent with full-EBM practices is associated with the research network of care, adjusted for patient-level characteristics. Secondary objectives were to determine the association between full-EBM and (1) hospitalisation and (2) emergency department (ED) revisits resulting in hospitalisation within 21 days.

Design

A secondary analysis of a retrospective cohort study.

Setting

38 paediatric EDs belonging to the Paediatric Emergency Research Network in Canada, USA, Australia/New Zealand UK/Ireland and Spain/Portugal.

Patients

Otherwise healthy infants 2–11 months old diagnosed with bronchiolitis between 1 January 2013 and 31 December, 2013.

Outcome measures

Primary outcome was management consistent with full-EBM, that is, no bronchodilators/corticosteroids/antibiotics, no chest radiography or laboratory testing. Secondary outcomes included hospitalisations during the index and subsequent ED visits.

Results

1137/2356 (48.3%) infants received full-EBM (ranging from 13.2% in Spain/Portugal to 72.3% in UK/Ireland). Compared with the UK/Ireland, the adjusted ORs (aOR) of full-EBM receipt were lower in Spain/Portugal (aOR 0.08, 95% CI 0.02 to 0.29), Canada (aOR 0.13 (95% CI 0.06 to 0.31) and USA (aOR 0.16 (95% CI 0.07 to 0.35). EBM was less likely in infants with dehydration (aOR 0.49 (95% CI 0.33 to 0.71)), chest retractions (aOR 0.69 (95% CI 0.52 to 0.91)) and nasal flaring (aOR 0.69 (95% CI 0.52 to 0.92)). EBM was associated with reduced odds of hospitalisation at the index visit (aOR 0.77 (95% CI 0.60 to 0.98)) but not at revisits (aOR 1.17 (95% CI 0.74 to 1.85)).

Conclusions

Infants with bronchiolitis frequently do not receive full-EBM ED management, particularly those outside of the UK/Ireland. Furthermore, there is marked variation in full-EBM between paediatric emergency networks, and full-EBM delivery is associated with lower likelihood of hospitalisation. Given the global bronchiolitis burden, international ED-focused deimplementation of non-indicated interventions to enhance EBM is needed.