bluuebunny/crossref_metadata_2025 huggingface dataset:
N95 respirators alter facial skin physiological functions and lipidome composition in health care personnel
Authors: Li Min , Wang Feifei , Tao Meng , Zhang Yue , Pan Ruoxin , Gu Duoduo , Zhong Hui , Xu Yang
Published: March 2024

Background

During the coronavirus disease 2019 pandemic, wearing medical respirators and masks was essential to prevent transmission.

Objective

To quantify the effects of N95 mask usage by measuring facial skin biophysical characteristics and changes in the lipidome.

Methods

Sixty healthy volunteers wore N95 respirators for 3 or 6 h. Facial images were acquired and physiological parameters were measured in specific facial areas, before and after mask‐wearing. Lipidome analysis was also performed.

Results

After N95 respirator usage, facial erythema was observed in both the 3 and 6 h groups. Both sebum secretion and trans‐epidermal water loss increased significantly in mask‐covered cheeks and chins after 6 h of mask wearing compared with before mask wearing (p < 0.05). Principal component analysis revealed significant differences in lipid composition after mask wearing compared with before. The ceramide subclass NS exhibited a positive correlation with stratum corneum hydration, whereas the AP subclass was negatively correlated with trans‐epidermal water loss in the 6 h group.

Conclusion

Prolonged wear of N95 respirators may impair facial skin function and alter lipidome composition.
Using simulation to teach paediatric complex care
Authors: Bruton Lucas , Spewak Michael
Published: March 2024

Background

Training paediatric residents regarding the care of children with medical complexity (CMC) remains an important challenge given how frequently these patients are treated by trainees and the lack of educational activities specific to these patients. Our goal was to develop and assess a novel simulation regarding the acute care of CMC to improve residents' perceived confidence in areas related to CMC care.

Approach

We developed a case of a patient with multiple chronic medical conditions who presented with acute vital sign changes and worsening discomfort due to an occult femur fracture related to a recent transfer. Paediatric residents worked in teams to complete a full physical exam, create a differential diagnosis, evaluate laboratory and imaging results and create a management plan.

Evaluation

Thirty‐three residents out of a total possible sample of 97 (34%) participated in the simulation, which was evaluated using pre‐ and post‐surveys immediately before and after the simulation assessing resident confidence completing tasks related to CMC care. Residents perceived significant improvement in confidence regarding evaluating a differential diagnosis of vital sign and exam changes in CMC (p = 0.023), managing vital sign and exam changes in CMC (p = 0.009) and communicating with team members of CMC (p = 0.049).

Implications

An innovative high‐fidelity and low‐stakes simulation was effective in teaching trainees about acute management of concerns related to CMC. This simulation may be appropriate for implementation at other institutions, serving as a foundation for use in resident education regarding CMC.
Association rule mining of air quality through an improved Apriori algorithm: A case study in 244 Chinese cities
Authors: Shen Keyi , Tian Ye , Hu Bisong , Luo Jin , Qi Shuhua , Chen Songli , Lin Hui
Published: March 2024

Predicting air pollution is complex due to intertwined factors among local climate, built environment, and development stages. This study leverages K‐means clustering and an improved Apriori algorithm to investigate the combined effects of local meteorological, morphological, and socioeconomic factors on air quality in 244 prefectural‐level Chinese cities. Results reveal that the secondary industry in GDP and saturation vapor pressure strongly relate to air quality. Severe air pollution occurs when urban development is coupled with reduced green areas and high temperatures, confirming that a single factor cannot predict air quality well. For example, we find that combining low population, low regional GDP, high maximum temperatures, and longer roads worsens air quality in small urban built‐up areas. Additionally, temperature and altitude differences associate with highway passenger volume, regional GDP, and population differently. Given our rules mining methods have broader applications in diversified urban environments, this study provides new insights for improving air quality and local Sustainable Development Goals.
Creative fictions: Incentive work and humanitarian labour in South Sudan
Authors: Newhouse Léonie S.
Published: March 2024

The career of the incentive has been meteoric and global, cropping up in peace‐building, state‐building, global health, and humanitarian contexts across the world. In this paper, I consider incentive work from the vantage point of independence‐era South Sudan. In doing so, I build conversations between geography and spatially sensitive anthropology about the power of social forms to shape action, through an attention to the porous and polyvalent logics of legitimation entailed in ‘creative fictions’. Attention to the modes of legitimation help to understand not only what social forms do, but also how they emerge, travel, and are appropriated and repurposed for use by new sets of actors. In tracing the transit of incentive work from development practice into humanitarian programming, I understand incentive work as a creative fiction—an intangible social form that animates and channels action to generative ends. While incentive work emerged as a tidy solution to constraints within the humanitarian sector on who might be paid for what kind work, the social form of incentive work proliferated. Set free from those constraints, incentive work offered up channels of accumuclation to new actors—including mid‐level state functionaries—by mobilizing and ligitimating claims on un‐ and under‐compensated labour though a call to voluntas, the morally inflected volitional ethos of volunteerism.
Evaluation of platelets componentized with the Reveos Automated Blood Processing System and stored for 7 days at room temperature in a non‐Di(2‐ethylhexyl) phthalate (DEHP) platelet pooling set
Authors: Reddoch‐Cardenas Kristin M. , Perez Samantha L. , Ferdin Justin N. , Meledeo Michael A.
Published: March 2024

Background

Platelet concentrates (PCs) used for transfusion can be produced by apheresis or derived from whole blood (WB). The Reveos device is the first US Food and Drug Administration‐approved automated blood processing system that can produce PCs. In this work, we evaluated the quality and function of Reveos‐collected PCs stored for 7 days at room temperature.

Study Design and Methods

WB was collected from healthy donors and componentized on the day of collection (Fresh) or after an overnight hold (Overnight). PCs were produced (n = 7 Fresh; n = 6 Overnight), stored at room temperature in plasma, and evaluated on days 1 and 7 for quality metrics, platelet activation, clot formation, and aggregation response.

Results

Platelet count was comparable between Fresh and Overnight PCs. A drop in pH was reported in Fresh day 7 PCs (p < .001, vs. day 1) but not in Overnight. Overnight units displayed the lowest levels of P‐selectin expression (p = .0008, vs. day 7 Fresh). Reduced clot strength and increased lysis were observed in both Fresh and Overnight units on day 7 (vs. day 1). Overnight‐hold PCs resulted in the highest clot strength on day 7 (p = .0084, vs. Fresh). No differences in aggregation were reported between groups.

Conclusion

Reveos‐processed PCs produced from overnight‐hold WB performed better in hemostatic function assays and displayed reduced activation compared to fresh WB‐derived PCs, although both PC groups maintained platelet quality throughout storage. Utilization of overnight WB for PC preparation with Reveos holds promise as an alternative method of producing platelets for transfusion purposes.
Sodium iodide symporter immunolabelling as a predictor of clinical iodide uptake in canine thyroid carcinoma: A preliminary study
Authors: Dark Katelin V. , Skinner Owen T. , Kim Dae Young , Karnia James J. , Mickelson Megan A. , Maitz Charles A.
Published: March 2024

Thyroid follicular tumours may take up iodide via the sodium‐iodide symporter. Knowledge of iodide uptake could then allow treatment with I‐131 in dogs with high‐risk tumours. The objective of this study was to determine the relationship between clinically detectable iodide uptake (as determined by scintigraphy and/or thyroxine concentrations) and sodium iodide symporter immunohistochemical labelling on histologically fixed thyroid tumours. Nineteen dogs were identified who were diagnosed with thyroid carcinoma and underwent surgery from November 2017 to July 2021. All had recorded thyroid hormone concentrations and were hyperthyroid and/or underwent preoperative nuclear imaging using planar scintigraphy (technetium‐99m or I‐123), or I‐124 PET‐CT. All dogs subsequently underwent surgery to remove the thyroid mass. Twenty‐two tumours were submitted for histopathologic analysis immediately following surgery, which confirmed a diagnosis of thyroid carcinoma for each tumour. Images and/or thyroid hormone concentrations were reviewed for the included cases, and tumours were sorted into an avid/functional group (group 1) and a non‐avid/functional group (group 2). The tumour tissues were re‐examined histologically using sodium iodide symporter (NIS) immunohistochemistry (IHC). Group 1 contained 15 avid/functional tumours. Twelve of these tumours had membranous NIS IHC labelling. Group 2 contained 7 non‐avid tumours. One of these tumours had membranous NIS IHC labelling. This resulted in an overall sensitivity and specificity for identification of avid/functional tumours with membranous NIS of 80.0% and 85.7%, respectively. NIS IHC may predict ion trapping in canine follicular thyroid tumours. Further studies using iodide‐based imaging are warranted to better determine the clinical utility of this diagnostic modality.
The association of bacterial agents and flagellated protozoans in the etiopathogenesis of subspectacular abscesses in snakes
Authors: Hellebuyck Tom , Kotyk Michael , Solanes Vilanova Ferran , Čepička Ivan
Published: March 2024

Objectives

To describe the etiology, clinical pathology, and treatment of subspectacular abscesses (SAs) in 16 snakes.

Animals Studied

Sixteen snakes from private captive collections that were presented at a veterinary teaching hospital and diagnosed with SAs.

Procedures

Exudate was collected from SAs via percutaneous aspiration or by performing a partial spectaculectomy and submitted to direct light microscopic examination and/or microbiological examination.

Results

Bacterial isolates were cultured from exudate samples in 12 out of 16 snakes and comprised Pseudomonas aeruginosa isolates that showed identical antimicrobial susceptibility patterns in seven cases. Direct light microscopic examination demonstrated the presence of flagellated protozoa in the exudate in 10 out of 16 snakes and in all of these snakes, concurrent oropharyngeal flagellated protozoan infection could be demonstrated. Combined flagellated protozoan and bacterial SA infection was demonstrated in six snakes. Comparison of small subunit ribosomal RNA gene sequences of flagellated protozoans that were detected in the exudate of SAs from four snakes revealed they represented the parabasalians Monocercomonas colubrorum and Hypotrichomonas acosta in one and three cases, respectively. In all snakes, successful treatment of the SAs was achieved following surgical debridement of the subspectacular space combined with antimicrobial treatment.

Conclusion

Bacteria as well as flagellates are considered to reach the subspectacular space through ascending infection from the oral cavity via the lacrimal duct. Although opportunistic bacterial infection presumably constitutes the predominant cause of SAs in snakes, the role of flagellate infection in the pathogenesis of this disorder should be further elucidated.
Moments of zeta and correlations of divisor‐sums: Stratification and Vandermonde integrals
Authors: Baluyot Siegfred , Conrey Brian
Published: March 2024

We refine a recent heuristic developed by Keating and the second author. Our improvement leads to a new integral expression for the conjectured asymptotic formula for shifted moments of the Riemann zeta‐function. This expression is analogous to a formula, recently discovered by Brad Rodgers and Kannan Soundararajan, for moments of characteristic polynomials of random matrices from the unitary group.
New Challenges: Archaeological heritage management and the archaeology of the 18th to 20th centuries. Foreword
Authors:   Historic Environment Scotland, Hale Alex , Kersting Thomas
Published: March 2024

In many places across Europe, it has long been common practice to protect, preserve and research monuments of the recent past. The many ways to approach archaeologies of the near present and recent past creates both a challenge and an opportunity for archaeological heritage management, and were considered in a number of papers from the 2023 EAC symposium and are now published here.
Massacres in the Arnsberg Forest (abstract)
Authors:   Aussenstelle Olpe, LWL-Archaeologie für Westfalen, Baales Michael , Weidner Marcus ,   LWL, Institut für westfälische Regionalgeschichte, Zeiler Manuel ,   Aussenstelle Olpe, LWL-Archaeologie für Westfalen
Published: March 2024

In recent years, an historical reappraisal by one of us (MW) has been carried out on one of the worst crimes outside of prisons and concentration camps committed in Germany by the SS and Wehrmacht in the final months of the Second World War. In the Arnsberg Forest near Warstein and Meschede (southern Westphalia, western Germany), 208 forced labourers were massacred by the 'Division for Vengeance' (Division zur Vergeltung) of SS General Hans Kammler in March 1945. In the course of this joint project, archaeological research conducted by the Olpe Department of the LWL-Archäologie für Westfalen (Westphalian Archaeological Heritage Service) has pinpointed the exact location of the crime scenes and provided clues for the reconstruction of the course of events in the field (Warstein Langenbachtal, Suttrop, Meschede-Eversberg). It has also enabled the recovery of finds belonging to both the victims and perpetrators. We have also been able to locate and examine the two temporary cemeteries (Warstein Melkeplätzchen, Suttrop). This has provided information about the history of exhumation of the victims in 1964, as well as clarifying the whereabouts of the Soviet obelisk from the Melkeplätzchen, the provisional cemetery of the Langenbach victims located close to the crime scene. This work has also allowed a follow-up search in the temporary cemetery in Suttrop for seven victims who, according to the exhumation documents of 1964, are presumably still lying there. Between 2018 and 2021, almost all of aspects addressed above could be clarified with new insights gained. Our results were summarised at the EAC conference in Bonn 2023 (although not published in this theme). Several publications already report on them and they are listed below. In addition to several German language publications, there is also an extensive English language publication (Baales et al. 2022) where the essential aspects of the interdisciplinary project are presented. In addition, the historical context, research project and numerous images are presented on several websites listed below.
The Protection of Archaeological Monuments from the 19th and 20th Centuries in Sweden
Authors:   Riksantikvarieämbetet, Gill Alesander
Published: March 2024

When the Swedish Historic Environment Act was amended in 2014, it became possible to safeguard specific sites of archaeological interest from the 19th and 20th centuries. However, since 2014, few younger sites have received protection. The most likely reason for this is related to a scarcity of resources at the county administrative boards.
Integral Transform Solution for Natural Convection Within Horizontal Concentric Annular Cavities
Authors: Pereira Luiz M. , Quaresma João N. N. , Pérez Guerrero Jesús S. , Cotta Renato M.
Published: March 2024

Natural convection inside horizontal concentric annular cavities is dealt with through the generalized integral transform technique (GITT), offering a hybrid numerical-analytical solution of the continuity, Navier–Stokes, and energy equations in cylindrical coordinates. The flow is in steady-state, laminar regime, two-dimensional, buoyancy-induced, and the governing equations are written in the streamfunction-only formulation. Two strategies of integral transformation are adopted to verify the best computational performance, namely, the usual one with eigenvalue problems for both streamfunction and temperature defined in the radial variable, and a novel alternative with eigenvalue problems defined in the azimuthal angular coordinate. First, the eigenfunction expansions convergence behavior is analyzed to critically compare the two integral transform solution strategies. Then, test cases for different aspect ratios and Rayleigh numbers are validated with experimental data from the classical work of Kuehn and Goldstein. A maximum relative deviation of 5% is found comparing the GITT results for the average Nusselt number against the experimental data, while an 8% maximum relative deviation is found comparing against an empirical correlation by the same authors. It is concluded that the GITT solution with the eigenvalue problem in the angular coordinate yields better convergence rates than the more usual eigenfunction expansion in the radial variable. This is due to the originally homogeneous boundary conditions in the angular direction, which do not require filtering for convergence enhancement, as opposed to the required filter in the radial direction that introduces a source term in the filtered equation for the streamfunction.
Effect of Strip-Fin Height on Jet Impingement Heat Transfer in a Rectangular Channel at Two Jet-to-Target Surface Spacings
Authors: Alzahrani Yasser S. , Wright Lesley M. , Han Je-Chin
Published: March 2024

An experimental investigation of heat transfer performance in a rectangular impingement channel featuring staggered strip-fins was completed. Four configurations were considered to study the effects of varying the strip-fin height (H/d = 1.5 and 2.75) at two jet-to-target surface spacings (z/d = 3 and 6) on the heat transfer, pressure loss, and crossflow magnitude for a long impingement channel with in-line, 4 × 12 impinging jets. Also, the effect of the reference temperature choice, either jet inlet temperature or local bulk temperature, for calculating the local heat transfer coefficients was considered. The regionally averaged heat transfer coefficients were measured at seven Reynolds numbers, based on the jet diameter (10k–70k) utilizing the copper plate experimental method. The empirical correlations were expressed for the area averaged Nusselt number estimation of impingement channels with strip-fin or pin-fin roughness elements. The results showed that the long strip-fin channel with z/d = 3 provided the best thermal performance. The discharge coefficients are similar for all configurations between Rejet = 10k and 50k. The results are compared with the impingement channels with conventional pin-fins. They show that strip-fin channels provide lower pressure drop with marginally better heat transfer coefficients compared to the conventional pin-fin channels. However, when the channel weight is considered, strip-fins would increase the roughness material volume more than the conventional pin-fins.
The Design and Optimization of Additively Manufactured Radial Compressor of a Miniature Gas Turbine Engine
Authors: Ergin Cagdas C. , Verstraete Tom , Saracoglu Bayindir H.
Published: March 2024

This paper presents a multidisciplinary design methodology for a single-stage radial compressor of a small-scale gas turbine jet engine. The entire engine, producing more than 600 N thrust with an engine diameter of less than 30 cm, will be manufactured by additive manufacturing (AM) in a single piece. Therefore, it is crucial to pinpoint the design limitations that may arise due to the AM methods. The preliminary design calculations are carried out in the Von Karman Institute for Fluid Dynamics (VKI's) in-house centrifugal compressor off-design (CCOD) code. The detailed design and optimization studies coupled with computational fluid dynamics (CFD) simulations are performed to improve the aerodynamic performance of the radial compressor by using the sequential quadratic programming (SQP) method with an Adjoint solver in the VKI's in-house computer aided design and optimization (CADO) tool. In the final design, a large increase in thrust is obtained and the manufacturing constraints are satisfied.
Experimental Analysis of the Improvement of Heat Transfer in Tube Heat Exchangers Via Passive Flow Generators Using Wire Coil Inserts
Authors: Ibrahim Farah Arina , Muhamad Mohd Ridha , Mohd Zubir Mohd Nashrul , Omar Mohd Bin , Siri Zailan , Hasan Rony Mehedy , Eid Mohamed Moustafa Abdelhalim Ahmed
Published: March 2024

Due to their high performance and low-cost demands, internally treated tube heat exchanger surfaces are one of the passive heat transfer enhancements that have caught the industry's attention. At bulk temperatures of 30 °C, an experiment for the insertion of 1 mm and 0.5 mm wire coils with a constant pitch length of 8 mm was carried out in this study. The results on the improvement of heat transfer, including the velocity profile, Nusselt number (6000 < Re < 20,000), friction factor, and thermal enhancement efficiency, were significant. Based on a lower surface temperature recorded beyond the uncertainty value, the results demonstrated an improvement in heat transfer for smaller diameter of wire coil inserts. It's interesting that this improvement is concentrated at low Reynolds numbers, indicating that there may be a point at which an increase in wire thickness does not necessarily result in an equivalent improvement in heat transfer. For both wire thicknesses, a Nusselt number increase of up to five times was visible. The friction factor penalty, however, varies depending on the wire thickness, with a higher magnitude (3.2-fold increase) obtained for 1 mm as opposed to a 1.8-fold increase for the lower counterpart. This distinction results in the 0.5 mm coil insert gaining better overall performance with an average of 2.2 for the thermal performance ratio, further solidifying the advantage of this technique for enhancing heat transfer in conduits. The diameter of the wire coil is found to be a key factor in improving heat transfer and convection on the boundary layer surface.
The Optimization of Distribution and Fan Parameters in Heat Treatment Furnaces Through the Integration of Numerical Simulation and Machine Learning
Authors: Zhao Jinfu , Xu Mingzhe , Wang Li , Zhao Tengxiang , Kong Ling , Yang Haokun , Huang Zhixin , Wang Yuhui
Published: March 2024

The present study employed numerical simulation technology to investigate the distribution of workpieces within a low-temperature trolley heat furnace and analyze the influence of circulating fan parameters on heat treatment quality. This analysis was integrated with machine learning technology to guide heat treatment production. The research findings indicate that when the number of workpieces remains constant, their position has a significant impact on airflow velocity distribution, heating rate, and temperature uniformity within the furnace. Additionally, wind pressure from the circulating fan affects both fluid field and temperature field; the increasing wind pressure leads to higher flow rates in the furnace as well as increases heating rates for workpieces. Heating efficiency exhibits a nonlinear relationship with wind pressure increment. By adjusting air pressure distribution from the circulating fan, workpiece temperature uniformity can be improved by 64%. Furthermore, machine learning technique demonstrates excellent performance in predicting workpiece temperatures with a maximum relative error of 2.4%, while maintaining consistent trends in temperature uniformity.
Normative Standards for Isokinetic and Anthropometric Classifications of University-Level Netball Players
Authors: Duvenage Kyra-Kezzia , Willemse Yolandi , de Ridder Hans , Kramer Mark
Published: March 2024

Context: The purpose of the study was to develop normative ranges and standards for knee and shoulder isokinetic and anthropometric values. These standards can be qualitatively interpreted and allow practitioners to classify isokinetic and anthropometric values more objectively for university-level netball players. Design: Posttest only observational study design. All players were only evaluated once during the in-season to generate normative ranges. Methods: A total of 51 female players volunteered. Participants were evaluated on an isokinetic dynamometer at 60° per second to obtain knee-extensor and knee-flexor values as well as shoulder-flexor and shoulder-extensor values. A total of 16 anthropometric variables were collected including stature, body mass, 8 skinfolds, and 6 circumferences. Between-group differences were calculated to determine whether playing level was a differentiating factor in data. Results: Normative standards were developed for isokinetic parameters associated with the knee and shoulder joints as well as skinfolds and circumference measures. No statistically significant between-group differences were evident (χ2Kruskal–Wallis[2] = 3.96, P = .140). Conclusion: These standards can be used by coaches and practitioners to set attainable goals for individual players or those from secondary leagues, classify individual and team-based performances, and facilitate decision-making processes.
Metabolic mechanism and pharmacological study of albendazole in secondary hepatic alveolar echinococcosis (HAE) model rats
Authors: Li Chaoqun , zhang Yaogang , Pang Mingquan , Zhang Yong , Hu Chunhui , Fan Haining
Published: March 2024

Albendazole (ABZ) is the primary treatment for alveolar echinococcosis (AE); however, its limited solubility impacts oral bioavailability, affecting therapeutic outcomes. In this study, various ABZ-solubilizing formulations, including albendazole crystal dispersion system (ABZ-CSD), albendazole hydrochloride-hydroxypropyl methylcellulose phthalate composite (T
ABZ-HCl-H
), and albendazole hydroxyethyl sulfonate-hydroxypropyl methylcellulose phthalate composite (T
ABZ-HES-H
), were developed and evaluated. Physicochemical properties as well as liver enzyme activity were analyzed and their pharmacodynamics in an anti-secondary hepatic alveolar echinococcosis (HAE) rat model were investigated. The formulations demonstrated improved solubility, exhibiting enhanced inhibitory effects on microcysts in HAE model rats compared to albendazole tablets. However, altered hepatic drug-metabolizing enzymes in HAE model rats led to increased ABZ levels and reduced ABZ-SO production, potentially elevating drug toxicity. These findings emphasize the importance of dose adjustments in patient administration, considering the impact of alveolar echinococcosis on rat hepatic drug metabolism.
Complete genome sequence of
Anaerotignum
sp. strain MB30-C6, isolated from sewage sludge of the wastewater treatment plant at a steel factory
Authors: Feng Fu , Wu Chih-Hung , Shih Chao-Jen , Wu Yen-Chi , Lai Shu-Jung , You Yi-Ting , Chen Sheng-Chung
Published: March 2024

We report the complete genome sequence of
Anaerotignum
sp. strain MB30-C6, which was isolated from the dehydrated sludge collected at the wastewater treatment plant of Sanming Steel Co. Ltd. in Fujian, China. The resulting genome of strain MB30-C6 is a single contig of 3,104,838 bp with 39.49% GC content.
Glycerol metabolism impacts biofilm phenotypes and virulence in
Pseudomonas aeruginosa
via the Entner-Doudoroff pathway
Authors: Pan Somalisa , Underhill Simon A. M. , Hamm Christopher W. , Stover Mylissa A. , Butler Daxton R. , Shults Crystal A. , Manjarrez Jacob R. , Cabeen Matthew T.
Published: March 2024

Pseudomonas aeruginosa
is a ubiquitous bacterium and a notorious opportunistic pathogen that forms biofilm structures in response to many environmental cues. Biofilm formation includes attachment to surfaces and the production of the exopolysaccharide Pel, which is present in both the PAO1 and PA14 laboratory strains of
P. aeruginosa
. Biofilms help protect bacterial cells from host defenses and antibiotics and abet infection. The carbon source used by the cells also influences biofilm, but these effects have not been deeply studied. We show here that glycerol, which can be liberated from host surfactants during infection, encourages surface attachment and magnifies colony morphology differences. We find that glycerol kinase is important but not essential for glycerol utilization and relatively unimportant for biofilm behaviors. Among downstream enzymes predicted to take part in glycerol utilization, Edd stood out as being important for glycerol utilization and for enhanced biofilm phenotypes in the presence of glycerol. Thus, gluconeogenesis and catabolism of anabolically produced glucose appear to impact not only the utilization of glycerol but also glycerol-stimulated biofilm phenotypes. Finally, waxworm moth larvae and nematode infection models reveal that interruption of the Entner-Doudoroff pathway, but not abrogation of glycerol phosphorylation, unexpectedly increases
P. aeruginosa
lethality in both acute and chronic infections, even while stimulating a stronger immune response by
Caenorhabditis elegans
.

IMPORTANCE

Pseudomonas aeruginosa
, the ubiquitous environmental bacterium and human pathogen, forms multicellular communities known as biofilms in response to various stimuli. We find that glycerol, a common carbon source that bacteria can use for energy and biosynthesis, encourages biofilm behaviors such as surface attachment and colony wrinkling by
P. aeruginosa
. Glycerol can be derived from surfactants that are present in the human lungs, a common infection site. Glycerol-stimulated biofilm phenotypes do not depend on phosphorylation of glycerol but are surprisingly impacted by a glucose breakdown pathway, suggesting that it is glycerol utilization, and not its mere presence or cellular import, that stimulates biofilm phenotypes. Moreover, the same mutations that block glycerol-stimulated biofilm phenotypes also impact
P. aeruginosa
virulence in both acute and chronic animal models. Notably, a glucose-breakdown mutant (Δ
edd
) counteracts biofilm phenotypes but shows enhanced virulence and stimulates a stronger immune response in
Caenorhabditis elegans
.
Fatty acids of
Helicobacter pylori
lipoproteins CagT and Lpp20
Authors: McClain Mark S. , Boeglin William E. , Algood Holly M. Scott , Brash Alan R.
Published: March 2024

Bacterial lipoproteins are post-translationally modified by the addition of acyl chains that anchor the protein to bacterial membranes. This modification includes two ester-linked and one amide-linked acyl chain on lipoproteins from Gram-negative bacteria.
Helicobacter pylori
lipoproteins have important functions in pathogenesis (including delivering the CagA oncoprotein to mammalian cells) and are recognized by host innate and adaptive immune systems. The number and variety of acyl chains on lipoproteins impact the innate immune response through Toll-like receptor 2. The acyl chains added to lipoproteins are derived from membrane phospholipids.
H. pylori
membrane phospholipids have previously been shown to consist primarily of C14:0 and C19:0 cyclopropane-containing acyl chains. However, the acyl composition of
H. pylori
lipoproteins has not been determined. In this study, we characterized the acyl composition of two representative
H. pylori
lipoproteins, Lpp20 and CagT. Fatty acid methyl esters were prepared from both purified lipoproteins and analyzed by gas chromatography-mass spectrometry. For comparison, we also analyzed
H. pylori
phospholipids. Consistent with previous studies, we observed that the
H. pylori
phospholipids contain primarily C14:0 and C19:0 cyclopropane-containing fatty acids. In contrast, both the ester-linked and amide-linked fatty acids found in
H. pylori
lipoproteins were observed to be almost exclusively C16:0 and C18:0. A discrepancy between the acyl composition of membrane phospholipids and lipoproteins as reported here for
H. pylori
has been previously reported in other bacteria including
Borrelia
and
Brucella
. We discuss possible mechanisms.

IMPORTANCE

Colonization of the stomach by
Helicobacter pylori
is an important risk factor in the development of gastric cancer, the third leading cause of cancer-related death worldwide.
H. pylori
persists in the stomach despite an immune response against the bacteria. Recognition of lipoproteins by TLR2 contributes to the innate immune response to
H. pylori
. However, the role of
H. pylori
lipoproteins in bacterial persistence is poorly understood. As the host response to lipoproteins depends on the acyl chain content, defining the acyl composition of
H. pylori
lipoproteins is an important step in characterizing how lipoproteins contribute to persistence.
Genetic and chemical control of tuberculostearic acid production in
Mycobacterium avium
subspecies
paratuberculosis
Authors: Bannantine John P. , Duffy Shannon C. , Colombatti Olivieri María A. , Behr Marcel A. , Biet Franck , Price Neil P. J.
Published: March 2024

Tuberculostearic acid (TBSA) is a fatty acid unique to mycobacteria and some corynebacteria and has been studied due to its diagnostic value, biofuel properties, and role in membrane dynamics. In this study, we demonstrate that TBSA production can be abrogated either by addition of pivalic acid to mycobacterial growth cultures or by a
bfaA
gene knockout encoding a flavin adenine dinucleotide (FAD)-binding oxidoreductase.
Mycobacterium avium
subspecies
paratuberculosis
(
Map
) growth and TBSA production were inhibited in 0.5-mg/mL pivalic acid-supplemented cultures, but higher concentrations were needed to have a similar effect in other mycobacteria, including
Mycobacterium smegmatis
. While
Map
C-type strains, isolated from cattle and other ruminants, will produce TBSA in the absence of pivalic acid, the S-type
Map
strains, typically isolated from sheep, do not produce TBSA in any condition. A SAM-dependent methyltransferase encoded by
bfaB
and FAD-binding oxidoreductase are both required in the two-step biosynthesis of TBSA. However, S-type strains contain a single-nucleotide polymorphism in the
bfaA
gene, rendering the oxidoreductase enzyme vestigial. This results in the production of an intermediate, termed 10-methylene stearate, which is detected only in S-type strains. Fatty acid methyl ester analysis of a C-type
Map bfaA
knockout revealed the loss of TBSA production, but the intermediate was present, similar to the S-type strains. Collectively, these results demonstrate the subtle biochemical differences between two primary genetic lineages of
Map
and other mycobacteria as well as explain the resulting phenotype at the genetic level. These data also suggest that TBSA should not be used as a diagnostic marker for
Map
.

IMPORTANCE

Branched-chain fatty acids are a predominant cell wall component among species belonging to the
Mycobacterium
genus. One of these is TBSA, which is a long-chain middle-branched fatty acid used as a diagnostic marker for
Mycobacterium tuberculosis
. This fatty acid is also an excellent biolubricant. Control of its production is important for industrial purposes as well as understanding the biology of mycobacteria. In this study, we discovered that a carboxylic acid compound termed pivalic acid inhibits TBSA production in mycobacteria. Furthermore,
Map
strains from two separate genetic lineages (C-type and S-type) showed differential production of TBSA. Cattle-type strains of
Mycobacterium avium
subspecies
paratuberculosis
produce TBSA, while the sheep-type strains do not. This important phenotypic difference is attributed to a single-nucleotide deletion in sheep-type strains of
Map
. This work sheds further light on the mechanism used by mycobacteria to produce tuberculostearic acid.
Antibacterial peptide Reg4 ameliorates
Pseudomonas aeruginosa
-induced pulmonary inflammation and fibrosis
Authors: Wan Xiaoyu , Wang Weipeng , Zhu Jing , Xiao Yongtao
Published: March 2024

Pseudomonas aeruginosa
(
P. aeruginosa
) is a Gram-negative facultative anaerobe that has become an important cause of severe infections in humans, particularly in patients with cystic fibrosis. The development of efficacious methods or mendicants against
P. aeruginosa
is still needed. We previously reported that regenerating islet-derived family member 4 (Reg4) has bactericidal activity against
Salmonella
Typhimurium, a Gram-negative flagellated bacterium. We herein explore whether Reg4 has bactericidal activity against
P. aeruginosa
. In the
P. aeruginosa
PAO1-chronic infection model, Reg4 significantly inhibits the colonization of PAO1 in the lung and subsequently ameliorates pulmonary inflammation and fibrosis. Reg4 recombinant protein suppresses the growth motility and biofilm formation capability of PAO1
in vitro
. Mechanistically, Reg4 not only exerts bactericidal action via direct binding to the
P. aeruginosa
cell wall but also enhances the phagocytosis of alveolar macrophages in the host. Taken together, our study demonstrates that Reg4 may provide protection against
P. aeruginosa
-induced pulmonary inflammation and fibrosis via its antibacterial activity.

IMPORTANCE

Chronic lung infection with
Pseudomonas aeruginosa
is a leading cause of morbidity and mortality in patients with cystic fibrosis. Due to the antibiotic resistance of
Pseudomonas aeruginosa
, antimicrobial peptides appear to be a potential alternative to combat its infection. In this study, we report an antimicrobial peptide, regenerating islet-derived 4 (Reg4), that showed killing activity against clinical strains of
Pseudomonas aeruginosa
PAO1 and ameliorated PAO1-induced pulmonary inflammation and fibrosis. Experimental data also showed Reg4 directly bound to the bacterial cell membrane and enhanced the phagocytosis of host alveolar macrophages. Our presented study will be a helpful resource in searching for novel antimicrobial peptides that could have the potential to replace conventional antibiotics.
Modification of Archean cratons in southern Africa with foundered segments dropped into the shallow lower mantle
Authors: Xi Jiaji , Yu Youqiang , Zhao Dapeng , Hu Jiashun
Published: March 2024

Subducted slabs have been detected in the lower mantle for almost 30 years, yet the presence of foundered cratonic segments in the lower mantle is still unclear and inadequately investigated. We present the first P-wave radial anisotropy tomography of southern Africa (our model SA-RAnis2024), which reveals a contrasting feature of preserved northwest and modified southeast Kalahari cratonic root. Segments from the modified cratonic lithosphere are inferred to have dropped into the shallow lower mantle where seismic evidence of isolated high-velocity anomalies are observed. We detect such a high-velocity anomaly under the southwest margin of the Kalahari craton, which possibly detached from the southeast Zimbabwe craton at ca. 60 Ma based on plate reconstructions. Foundered segments can be partially brought back up to shallow depths, and contribute to the geochemical heterogeneity of younger lithosphere, through large-scale mantle convection.
One-year efficacy of myopia control by the defocus distributed multipoint lens: a multicentric randomised controlled trial
Authors: Chen Xiaoqin , Li Mengdi , Li Jun , Wu Min , Liu Xiaonan , Yu Cui , Guo Xingyi , Wang Yanbo , Wang Yansong , Lu Wenli , Li Lihua , Wang Yan
Published: March 2024

Aims

To report the 1-year results of the efficacy of a defocus distributed multipoint (DDM) lens in controlling myopia progression in a multicentre, randomised controlled trial.

Methods

Overall, 168 children aged 6–13 years were recruited and randomly assigned to wear a DDM lens (n=84) or single-vision (SV) lens (n=84) in three centres. Cycloplegic autorefraction (spherical equivalent refraction (SER)) and axial length (AL) were measured. Linear mixed model analysis was performed to compare between-group SER and AL changes. Logistic regression analysis was used to analyse the between-group difference in rapid myopia progression (SER increase≥0.75 D per year or AL growth≥0.40 mm per year).

Results

After 1 year, mean changes in SER were significantly lower in the DDM group (−0.47±0.37 D) than in the SV group (−0.71±0.42 D) (p<0.001). Similarly, mean changes in AL were significantly lower in the DDM group (0.21±0.17 mm) than in the SV group (0.34±0.16 mm) (p<0.001). After adjusting for age, sex, daily wearing time and parental myopia, rapid myopia progression risk was higher in the SV group than in the DDM group (OR=3.51, 95% CI: 1.77 to 6.99), especially for children who wore a lens for >12 hours per day, boys and younger children (6–9 years) with ORs (95% CIs) of 10.82 (3.22 to 36.37), 5.34 (1.93 to 14.78) and 8.73 (2.6 to 29.33), respectively.

Conclusions

After 1 year, DDM lenses effectively retarded myopia progression in children. Longer daily wearing time of DDM lens improved the efficacy of myopia control. Future long-term studies are needed for validation.

Trial registration number

NCT05340699
.
Towards global elimination of lymphatic filariasis: a systematic review of the application of spatial epidemiological methods to enhance surveillance and support elimination programmes
Authors: Martin Beatris Mario , Cadavid Restrepo Angela , Mayfield Helen J , Lau Colleen L
Published: March 2024

Background

In recent decades, spatial epidemiology has increasingly been used to study neglected tropical diseases (NTDs). Spatial methods are particularly relevant when transmission is strongly driven by sociodemographic and environmental factors, resulting in heterogeneous disease distribution. We use lymphatic filariasis (LF)—an NTD targeted for global elimination—as a case study to examine how spatial epidemiology has been used to enhance NTD surveillance.

Methods

We conducted a systematic literature review of spatial analytical studies of LF published in English across PubMed, Embase, Web of Science and Scopus databases, before 15 November 2022. Additional papers were identified from experts’ suggestions. Studies that employed spatial analytical methods were included, but those that applied only visualisation tools were excluded.

Findings

Sixty-one eligible studies published between 1997 and 2023 were identified. The studies used a wide range of spatial methods. Thirty-one (50.8%) studies used spatial statistical modelling, with model-based geostatistics being the most common method. Spatial autocorrelation and hotspot analysis were applied in 30 studies (49.2%). The most frequent model outputs were prevalence maps (17 studies, 27.9%), followed by risk maps based on environmental suitability (7 studies, 11.5%) and maps of the odds of seroprevalence being above a predetermined threshold (7 studies, 11.5%).

Interpretation

By demonstrating the applicability of spatial methods for investigating transmission drivers, identifying clusters and predicting hotspots, we highlight innovative ways in which spatial epidemiology has provided valuable evidence to support LF elimination. Spatial analysis is particularly useful in low-prevalence settings for improving hotspot detection and enhancing postelimination surveillance.

PROSPERO registration number

CRD42022333804.
Changes in fertility intention among married Chinese couples with two children during COVID-19: a cross-sectional study
Authors: Ning Ni , Tan Xiangmin , Li Ying , Tang Jingfei , Lommel Lisa , Sun Mei
Published: March 2024

Background

A three-child policy was implemented in China to stimulate a rise in fertility levels and coincided with the COVID-19 pandemic. Data suggested that COVID-19 has a negative impact on fertility intention.

Aim

To describe married couples’ changes in intention to have a third child during the COVID-19 pandemic and determine factors associated with altered intentions.

Methods

An online survey was conducted in October 2021, including sociodemographic characteristics, change of intention to have a third child after the COVID-19 pandemic outbreak, reasons for increased or decreased intention, and the Fertility Intention Scale (FIS). Bivariate and multivariable logistic regression were used to test the potential factors associated with changes in intention.

Results

A total of 1308 participants provided responses. Following the COVID-19 outbreak, 35.8% of participants decreased their third-child intention, while 2.8% of participants increased their third-child intention. Males (aOR 1.90, 95% CI 1.42 to 2.54), youngsters (aOR 1.77, 95% CI 1.08 to 2.93) and those living in Estern China (aOR 2.12, 95% CI 1.13 to 3.98) were more likely to decrease their third-child intention. Perceived risk (aOR 1.07, 95% CI 1.03 to 1.10) and policy support (aOR 1.06, 95% CI 1.03 to 1.09) as measured on the FIS decreased couples’ intention to have a third child. Social support (aOR 0.94, 95% CI 0.91 to 0.98) as measured on the scale protected participants from decreased intention.

Conclusions

During severe public health emergencies, strong prevention and control policies, together with enhancing support from partners and healthcare professionals for women, are necessary to improve intentions to give birth.
Understanding the impact of COVID-19 on women’s access to and experiences of contraceptive services in England: a qualitative study
Authors: McMillan Lauren , Gadsby Erica , Howell Rebecca , Ussher Michael , Hunt Kate , Ford Allison
Published: March 2024

Background

The COVID-19 pandemic response prompted rapid changes to how contraceptive services were delivered in England. Our aim was to examine women’s experiences of accessing contraceptive services since March 2020 and to understand any inequalities of access.

Methods

We conducted telephone interviews with 31 women aged 17–54 years who had accessed contraceptive services in England since March 2020. The sample was skewed to include participants with lower educational attainment and higher deprivation. Interview transcripts were thematically analysed using inductive and deductive approaches.

Results

Few differences were found regarding educational attainment. Participants using contraceptive injections (all living in areas in the most deprived quintile) reported the greatest access challenges. Some switched method or stopped using contraception as a result. More general barriers reported by participants included service closures, unclear booking processes, and lack of appointment availability. Many participants welcomed the flexibility and convenience of remote contraceptive services. However, telephone appointments posed challenges for those at school or living with parents, and some described them as rushed and inconducive to asking questions or raising concerns. Those accessing contraception for the first time or nearing menopause felt they were unable to access sufficient support and guidance during the pandemic. Some participants voiced concerns around the lasting effects of COVID-19 on appointment availability and inadequate service delivery.

Conclusions

Women’s experiences of accessing contraceptive services in England since March 2020 are diverse. While remote services were suitable for some, COVID-19 restrictions unequally impacted women depending on their method of contraception and life stage.