bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling the thermal effects of stimulus airflow from the Dolphin aesthesiometer on a model eye surface
Authors: Mungalsingh Melanie A. , Thompson Benjamin , Peterson Sean D. , Murphy Paul J.
Published: December 2024

Purpose

To assess the ability of the Dolphin air‐pulse aesthesiometer to present multiple stimuli, which are separated temporally (in sequence) or spatially (simultaneously).

Methods

Two studies were performed to explore the cooling effects induced by double air‐puff stimuli generated by a novel aesthesiometer composed of two micro‐blower integrated units. The stimuli were delivered sequentially or simultaneously at the same or different spatial locations to an in vitro eye model monitored using thermography. The model eye was based on a 2‐cm LED dome light mounted on a circuit board with an 8‐V supply producing a baseline 32°C temperature. Single and repeated air‐pulse stimuli varying in intensity, duration, inter‐stimulus delay and stimulus location were presented to the model. The cooling effect produced was observed using a thermal camera and quantified using image analysis software.

Results

The instrument can deliver single stimuli, repeated single stimuli with a variable time delay or multiple stimuli either simultaneously or with a time delay between them. The thermal effects of stimuli were evaluated by measuring (relative to pre‐stimulus baseline) the local temperature change and the diameter of the model eye surface region with ≥1°C reduction. Repeated stimuli at the same location produced a significantly greater effect than a single stimulus of the same intensity (larger area of cooling after the second stimulus compared to the first [|M|{SE} = 1.48 mm {0.06}, p < 0.001]). Spatially separated stimuli produced separate cooling zones, with the amount of cooling relative to stimulus intensity (rm‐ANOVA, F2,8 = 276.01, p < 0.001, 2 = 0.96).

Conclusions

The combined use of two micro‐blower units allows increased options for modification of stimulus intensity and timing of delivery that enables the production of alternative stimulus presentations and intensity compared to a single stimulus. This adaptability may enable future in vivo study of corneal sensory nerve summation.
Behavioral Determinants of Older Adults’ and Caregivers' Willingness to Deprescribe: A Systematic Review
Authors: Alves Jorge Sara , Van den Broucke Stephan , Koumba Maguena Ruth‐Janet , Spinewine Anne
Published: December 2024

Background

Deprescribing is a strategy to optimize medication use and to prevent medication harm. Despite the fact that behavioral theories have been shown to be useful in explaining health behaviors, the literature on deprescribing relies almost exclusively on attitudes as an explanatory factor for deprescribing behavior. This study systematically reviews the literature that made explicit use of the constructs included in health behavior theories (HBTs) to explain older adults’ and informal caregivers’ deprescribing behavior and outcomes.

Methods

Studies were screened from five electronic databases by two reviewers. Quantitative interventional and non‐interventional studies applying at least one HBTs or construct from these theories to older adults' or informal caregiver' intention or behavior to deprescribe, were included. Studies that used the patients’ attitudes toward deprescribing (PATD) questionnaire or its revised version were excluded.

Results

A total of 11 non‐interventional studies and 11 interventional studies were identified, seven of which applied HBTs, and the other 15 used constructs from the HBTs. Health literacy and locus of control were identified as moderator variables. Only two studies targeted informal caregivers’ deprescribing intentions or behavior.

Conclusions

HBTs are not systematically used. However, combining the main HBT constructs reported in the literature offers a better explanation of the (intention to) engage in deprescribing.

Trail Registration

The study protocol (ID: CRD42022378157) was published on PROSPERO.
Auto‐Bäcklund Transformations for New Matrix First and Second Painlevé Hierarchies
Authors: Gordoa Pilar Ruiz , Pickering Andrew
Published: December 2024

We define a new doubly extended matrix second Painlevé hierarchy, and in addition a new extended matrix first Painlevé hierarchy. For the former, we present three auto‐Bäcklund transformations (auto‐BTs) that constitute nontrivial extensions to our new hierarchy of previously derived results on the auto‐BTs of a much simpler matrix second Painlevé hierarchy; for the latter, we define an auto‐BT analagous to the third of these matrix second Painlevé auto‐BTs. In addition, for both of our new hierarchies, we define a new class of auto‐BT. In the scalar reduction, these then give rise to a new Bäcklund process for the second Painlevé equation, as well as to a similar Bäcklund process for the first Painlevé equation. These new Bäcklund processes provide mappings of arbitrary constants appearing in solutions.
The Riemann Problem for the Flow Pattern in Deviated Pipes Carrying Isentropic Two‐Phase Flows
Authors: Shah Sarswati
Published: December 2024

We study the Riemann problem for the one‐dimensional two‐phase isentropic flow in deviated pipes. The model under consideration is nonconservative and conditionally strictly hyperbolic. The generalized Rankine–Hugoniot conditions are established for the present system with nonconservative products to define weak solutions. Exact Riemann solutions are presented in fully explicit forms for the nonhomogeneous model, where the elementary waves are discussed along parabolic curves. Moreover, it is demonstrated that a delta shock wave appears in the Riemann solutions under specific conditions when the pressure vanishes.
Uniform Asymptotic Expansions for the Zeros of Parabolic Cylinder Functions
Authors: Dunster T. M. , Gil Amparo , Ruiz‐Antolin Diego , Segura Javier
Published: December 2024

The real and complex zeros of the parabolic cylinder function are studied. Asymptotic expansions for the zeros are derived, involving the zeros of Airy functions, and these are valid for positive or negative and large in absolute value, uniformly for unbounded (real or complex). The accuracy of the approximations of the complex zeros is then demonstrated with some comparative tests using a highly precise numerical algorithm for finding the complex zeros of the function.
DESIGN AND SIZING OF STAND-ALONE PHOTOVOLTAIC SYSTEMS FOR REMOTE AREAS
Authors: Ira Devi Sara  , Rosmin Norzanah , Muhammad Bahi  , Mohd Zulkepli Hammad Daniel
Published: December 2024

As solar photovoltaic technology becomes more affordable globally, Stand-Alone Photovoltaic (SAPV) systems are being recognized as a viable solution for powering essential services in areas lacking grid connectivity. The paper begins with a comprehensive review of SAPV systems, highlighting their categorization, benefits, and typical applications, especially in remote areas. Subsequently, it delves into the design and sizing aspects of these systems, emphasizing the importance of choosing appropriate components, including PV modules, batteries, charge controllers, inverters, and cables. A detailed methodology outlines the intuitive design process, incorporating factors like site selection, solar potential assessment, daily energy needs calculation, and component sizing. This systematic yet straightforward methodology bridges the gap between theoretical design principles and practical implementation. To demonstrate the applicability of the proposed approach, a case study is included, offering real-world insights and best practices for SAPV system deployment. This study contributes to the field of renewable energy by addressing specific challenges associated with SAPV system design in off-grid areas, such as the need for accurate solar irradiation data and precise component sizing. By providing a structured framework and practical guidance, this work serves as a valuable reference for researchers, engineers, and policymakers aiming to optimize SAPV systems for sustainable development and to enhance energy access in remote regions.
A Review of Medical Device Procurement at National Level: Integrating Support Systems for Clinical Engineers Towards Efficient, Transparent and Standardized Procurement Processes
Authors: Mohamad Salim Maheza Irna , Ahmed Al-Ashwal Rania Hussein , Tan Tian Swee , Abuzairi Tomy
Published: December 2024

This study explores the role and the key support system required by clinical engineers in enhancing national-level medical device procurement to ensure efficiency, safety and standardization. Using WHO's 2022 data from 11 South-East Asian countries as a foundation, the review identifies critical gaps in the national-level procurement infrastructure, particularly in the availability of regulatory support, standardized procurement processes and technical specifications to support the national level procurement practice. These deficiencies highlight the need for a robust framework that supports clinical engineers in making informed, evidence-based procurement decisions. The study also emphasizes the importance of Health Technology Assessment (HTA) and Clinical Evidence Databases (CED) as essential tools for evaluating the safety, effectiveness and long-term performance of medical devices. In addition to technical evaluation, the research highlights the necessity of standardized procurement guidelines and detailed technical specifications to reduce variability in device quality and ensure compliance with national and international standards. The role of continuous education and training is also examined, stressing that clinical engineers must stay updated on advancements in medical technology, regulatory requirements and sustainability practices to effectively support procurement processes. By continuously upgrading their knowledge and skills, clinical engineers can ensure that procurement decisions are aligned with the current best practices and healthcare priorities. Collaboration among key stakeholders including governments, regulatory authorities, manufacturers and clinical engineers is identified as crucial for establishing transparent, efficient, and equitable procurement systems. Regulatory bodies must ensure that all devices meet stringent safety and performance standards, while manufacturers need to provide accurate technical data and engage in sustainable production practices. Governments, in turn, play a critical role in centralizing procurement processes, standardizing guidelines and facilitating partnerships across the public and private sectors. This research concludes that by effectively putting clinical engineering support systems in place, national procurement strategies can be significantly enhanced. It is hoped that this integration will not only streamline procurement processes but also improve healthcare delivery and patient outcomes in ensuring that devices procured at the national level meet the highest standards of safety, quality, and sustainability.
PGMI.Vision: A Mobile Application for Breast Mammographic Image Quality Evaluation with Usability Analysis
Authors: Abdulla Hamid Syakirah Athirah , Wan Mustaffa Fikr Wan Siti Khadijah , Khairi Fatin Liyana , Abdille Mahdi Osman , Aulia Salma  , Jais Nur Afifah Zahidah , Ahmed al-Babakri Turki Salem , Anil Husna Aqilah Hannani , Hamizun Nur Farisha Hanna , Sahalan Mariaulpa
Published: December 2024

The PGMI classification approach is used in Malaysia to assess mammography quality. However, the PGMI criteria lack objectivity and clear definitions, leading to inconsistent evaluations by different readers. This challenge ensures that all mammography facilities fulfil the basic quality criteria. This study aims to develop a mobile application for objective mammography quality assessment and usability evaluation. Figma was utilized as a design tool for this project to create the PGMI mobile application, called PGMI.Vision, due to its interactive design capabilities and collaborative features. The app includes two important mammography views: craniocaudal (CC) and mediolateral oblique (MLO) each breast, resulting in a set of four images. The study involved 27 participants and used the Usefulness, Satisfaction, and Ease of Use (USE) Questionnaire for evaluation. Usability testing showed the average score for Usefulness was 81.67%, Ease-of-Use was 81.82%, Ease of Learning was 80.93%, and Satisfaction was 79.68%. The overall average score was 81.02%, which exceeds typical benchmarks in USE Questionnaire studies, indicating high user satisfaction and usability. These high scores suggest PGMI.Vision is user-friendly and exhibit significant potential for future use.
Synthesis and Characterization of Nano-Hydroxyapatite Particles by Using Co-Precipitation Method for Bone Scaffold
Authors: Mohd Amin Murfiqah Taufiqiah , Jusoh Norhana , Abdul Samad Adlisa
Published: December 2024

Hydroxyapatite has become an important material for bone scaffold fabrication. Various method has been investigated in developing nano-hydroxyapatite that mimicking the native bone properties. Co-precipitation approach is the best synthesis method due to capability in producing hydroxyapatite with controlled size and morphology. However, to determine the parameters in producing good hydroxyapatite has become a challenge. Therefore, the aim of this study is to synthesis the nano-hydroxyapatite with right size and composition via co-precipitation method. In this study, calcium nitrate tetrahydrate and ammonium phosphate dibasic were mixed for 3 hours at pH11 before left ageing for 24 hours. The morphology of the hydroxyapatite nanoparticle was in rod-like look as observed by Transmission Electron Microscopy (TEM). The average diameter of the hydroxyapatite nanoparticle was 8.49 ± 0.36 nm, whereas the average length was 37.46 ± 1.86 nm. Energy Dispersive X-ray Spectroscopy (EDX) analysis yield the result of Ca/P ratio of 1.43 which is close to the stoichiometry of hydroxyapatite, 1.67. Produced nanoparticle confirmed co-precipitation method is the best choice in synthesizing nano size hydroxyapatite that suitable for bone tissue engineering application.
Anion Titration Studies of Tetramide Compounds as A Potential Chromate Separation Materials
Authors: Abdul Kadir Maisara , Razak Fazira Ilyana , Haris Nur Shuhaila Haryani
Published: December 2024

This study describes the synthesis and characterization of two tetraamide compounds namely, 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]ethane (L1) and 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]propane (L2) which were prepared by reacting N-6-[(4-pyridylmethylamino)carbonyl]-pyridine-2-carboxylic acid methyl ester with ethane-1,2-diamine and propane-1,3-diamine, respectively. These types of compounds are commonly studied for anion separation materials due to their pre-organized structure that is readily intended to capture anion via hydrogen bonding. Characterization of L1 and L2 was conducted by Fourier Transform Infrared spectroscopy (FTIR), 1H and 13C Nuclear Magnetic Resonance (NMR). The structure conformation was supported by theoretical studies which were conducted through DFT analysis. Evaluation of the potential of these compounds to interact with chromate anions was investigated using the UV-Vis titration technique. The results showed that L1 has a good affinity towards chromate anions compared to L2. This result concluded that the utilization of smaller spacer units such as ethyl contributed to the ease of binding of a molecular host to chromate anions through NH amide binding pockets, compared to the use of a lengthier spacer.
Remediation of Acidic Soil with Mission Grass (Pennisetum polystachion) Grounds
Authors: Khamis Aidee Kamal , Asli Umi Aisah , Mohd Noor Norfakhrina , Dib Julián Rafael , Zailani Siti Nazrah
Published: December 2024

Lime (CaCO3) application is the most common practice to neutralise soil acidity before planting. However, the effectiveness of liming depends on its reactivity and interactions with various soil types. Therefore, mission grass (Pennisetum polystachion; PP) grounds have been proposed as an alternative for soil acidity remediation, owing to their rapidly decomposable residue and release of basic cations. This study evaluated the ability of PP to increase the pH and the relationship between pH and redox potential (Eh) in loamy soil and sandy soil. The addition of 2.5% (w/w) CaCO3 rapidly increased the pH in loamy soil but gradually decreased the pH in sandy soil, with a value of 7.30 and 7.50, respectively, on day 20. The addition of 2.5% (w/w) PP increased the pH in loamy soil and sandy soil to 5.60 and 6.50, respectively, on day 20. The Eh value in loamy soil was significantly lower after the addition of PP compared with CaCO3 (+50.0 mV and + 200.0 mV, respectively). In sandy soil, the addition of PP produced a lower Eh value on day 20 compared with the addition of CaCO3. The fluctuating Eh values in both soil types were associated with soil moisture, electrical conductivity and organic matter and should be measured systematically with pH. The addition of PP was beneficial in slowly increasing the soil pH over time, thus influencing the favourable reducing condition as indicated by the lower Eh values. The application of PP as an alternative and a complement to the conventional liming practice should be further studied to reduce the adverse impacts on the soil to establish a balance between agricultural productivity and sustainable agriculture.
Antibacterial Activity of the Chemically Synthesized Zinc Oxide Nanoparticles against Gram-Negative and Gram-Positive Bacteria
Authors: Wazir Arshad Hussain , Khan Qudratullah , Ahmad Afaq , Ullah Inayat
Published: December 2024

Zinc oxide nanoparticles (ZnO NPs) are highly important due to their high photocatalytic and antibacterial activities. ZnO NPs are used as antibacterial agents because they have significant antibacterial properties, inexpensive, easy to synthesize, high surface area-to-volume ratio, and non-toxic to human cells, making them effective and safe for medicinal applications. This study also concentrates on the preparation and characterization of ZnO NPs and their antibacterial activities. A simple chemical process was performed to synthesize ZnO NPs from an aqueous solution of zinc salt (zinc chloride) and an aqueous solution of sodium hydroxide under an alcoholic methanol media. The obtained product was analyzed using Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-Vis) and X-ray diffractometry (XRD). The mean crystallite size of ZnO nanocrystals was 32.64 nm, as calculated from main X-ray diffraction peaks employing the Scherrer formula. FTIR analysis revealed the presence of carbonyl and carboxyl functional groups on the surface of ZnO nanoparticles, which enhance interactions with bacterial cell membranes and contribute to their antibacterial activity. ZnO nanoparticles with a prominent and broad absorption peak at a maximum wavelength (λmax) of 375 nm demonstrate highly effective antibacterial properties. The synthesized ZnO nanoparticles displayed antibacterial activity against pathogenic strains of Klebsiella pneumoniae, Escherichia coli (gram-negative), and Staphylococcus aureus (gram-positive). The results indicated that the chemically synthesized ZnO nanoparticles exhibited effective antibacterial properties.
Tetracycline Biodegradation by Shigella flexneri strain TA_E_3 Isolated from Wastewater Treatment Plant
Authors: Jaffar Muhammad Syahmi , Mohd Zain Nor Azimah
Published: December 2024

Although the transformation of tetracycline (TEC) by abiotic mechanisms has been extensively reported in literature, knowledge on the potential degradation of TEC by microbial activities in aquatic environments is still scarce. Some limitations are present for tetracycline biodegradation including the typical metabolite products that have been produced by the Shigella flexneri TA_E_3. Therefore, the purpose of this study is to investigate the by-products produced during biodegradation of tetracyclines by using Shigella flexneri TA_E_3 as model, and to determine the possible TEC degradation by-products and metabolic pathway. The changes in the concentration of the TEC were measured within 6 hours of degradation. TEC degradation by-products produced from biodegradation by strain TA_E_3 have been studied. The result shows that danazol is the main biodegradation product identified using LC-MS Q TOF analysis. Potential degradation pathways were then proposed including the removal of amide, carbonyl, and amine groups, alongside the isomerisation of the parent compound. The findings of this work can serve as a theoretical foundation for more accurate predictions of antibiotic destiny, transit, and degradation in aquatic environments.
Optimization of Piper sarmentosum Extract Concentration and Exposure Time to Inhibit Biofilm Formation of Dental Plaque-Causing Bacteria
Authors: Yong Sze Min , Ab Latif Nurriza , Ab Latif Nurzila
Published: December 2024

Streptococcus mutans and Streptococcus sobrinus are the primary oral pathogens that can lead to the formation of dental plaque. Piper sarmentosum is a medicinal plant has the potential alternative solution to solve the problem. The objectives of this project were to optimize the extraction concentration, total phenolic compounds (TPC) and total flavonoid compounds (TFC) in P. sarmentosum by using 80% methanol and 95% ethanol as the extraction solvents and the exposure time of the extract of P. sarmentosum to inhibit the biofilm formation of both S. mutans and S. sobrinus. The extract with higher TPC and TFC was screened by using GC-MS analysis. The minimum inhibitory concentration (MIC) of the plant extract against the oral pathogen was determined by using an MTT colourimetric assay. The anti-adherence and biofilm-inhibitory assays were performed when the exposure time of the plant extract towards the oral pathogen reached 1, 3, 6 and 24 hours. The 80% methanolic extract exerts a higher ability to extract more phenolic and flavonoid compounds compared with 95% ethanol as the extraction solvent. The MIC of the 80% methanolic extract towards S. mutans and S. sobrinus was 50 mg/mL and 100 mg/mL, respectively. A dose-dependent manner was observed in both anti-adherence and biofilm inhibitory assays. The best biofilm-inhibitory activity was observed when the exposure time of the plant extract towards the oral pathogen reached 1 hour. These findings served as preliminary ideas about the potential of P. sarmentosum to develop into oral care products.
The Lelek fan admits a completely scrambled weakly mixing homeomorphism
Authors: Oprocha Piotr
Published: December 2024

We prove that the Lelek fan admits a completely scrambled weakly mixing homeomorphism. This is then used to show that for every there is a continuum of topological dimension admitting a weakly mixing completely scrambled homeomorphism. This provides a final answer to a question from 2001.
Hip Adduction and Abduction Strength Reference Values of Gaelic Football and Rugby Union Players: A Cross-Sectional Study
Authors: O’Connor Ciaran , McIntyre Martin , Delahunt Eamonn , Thorborg Kristian
Published: December 2024

Purpose: The purpose of this research was to report isometric hip adduction and abduction strength reference values of men’s and women’s Gaelic football and rugby union players and compare values between sexes and between sports. Methods: This cross-sectional cohort study consisted of 331 club-level athletes. Maximum isometric hip adduction squeeze and abduction press strength values were measured with a ForceFrame across several testing positions. Results: Hip adduction squeeze and abduction press strength reference values for men’s and women’s Gaelic and rugby union footballers were provided with mean and 1 SD. A 2-way analysis of variance demonstrated significant sport × sex interaction main effects for hip adduction squeeze (η2 = .159–.228), abduction press (η2 = .099–.144), and adduction:abduction ratio (η2 = .120). Men demonstrated significantly greater relative (Newtons per kilogram) maximum isometric hip adduction squeeze (15.5%–26.4%, 0.48–1.00 N/kg) and hip abduction press (9.6%–19.6%, 0.20–0.67 N/kg) strength across all testing positions when compared with women of the same sport. Male Gaelic football players demonstrated significantly greater hip adduction (8.7%–14.0%, 0.30–0.52 N/kg) and abduction (6.1%–8.6%, 0.16–0.31 N/kg) strength (Newtons per kilogram) than their rugby counterparts, while no significant between-sports differences in strength were observed between female athletes. Conclusion: Reference values are provided with mean and 1 SD. Sport and sex interaction had significant main effects for hip adduction, abduction, and adduction:abduction ratio, with medium to large effect sizes. Male athletes demonstrate significantly greater hip strength than female athletes of the same sport, and male Gaelic players demonstrate greater hip strength than male rugby players.
On Belay: Navigating the Enrollment Cliff in Kinesiology
Authors: Sutherland Sue , Goodway Jacqueline D.
Published: December 2024

This paper addresses a critical issue in higher education by providing an overview of the enrollment cliff, its implications for Kinesiology programs in the United States, and strategies to tackle the enrollment cliff. Survey your Landscape—institutions across the United States brace for demographic shifts expected to reshape the student population over the coming decade and beyond. Know your own Rock Face—Kinesiology programs are varied in scope and size based on factors such as location, institution type, size, and curriculum and/or subprograms. However, there are common issues that each program faces that can exacerbate the impact of the enrollment cliff. Plan your Route, Anchors, and Safety System—Kinesiology programs must adopt a multifaceted approach that emphasizes recruitment, retention, and resource optimization. By strategically aligning program offerings with market demand, engaging in proactive outreach, and fostering strong partnerships, Kinesiology programs can successfully climb the enrollment cliff.
Increasing rates of
erm
(B) and
erm
(N) in human
Campylobacter coli
and
Campylobacter jejuni
erythromycin-resistant isolates between 2018 and 2023 in France
Authors: Jehanne Quentin , Bénéjat Lucie , Ducournau Astrid , Aptel Johanna , Pivard Marie , Gillet Léo , Jauvain Marine , Lehours Philippe
Published: December 2024

Macrolides are the first-line compounds used for the treatment of campylobacteriosis. Macrolide resistance remains low in France, with mutations in
23S rDNA
being the main associated resistance mechanism. However, two erythromycin methyltransferases have also been identified
: erm
(B), which is mainly described in animal reservoirs, and
erm
(N), which is strictly described in humans. In France, between 2018 and 2023, erythromycin-resistant
Campylobacter
species strains were systematically sequenced and analyzed
via
an in-house bioinformatics pipeline, leading to the identification of the resistomes, MLST and cgMLST, as well as the characterization of the source of contamination. In this study, the genomes of 280 erythromycin-resistant strains were sequenced over a 6-year period. The identification of erythromycin-associated resistance markers revealed a predominance of
23S rDNA
mutations, in 90% of cases, but also
erm
-type methyltransferases in 10% of cases: 75% for
erm
(N) and 25% for
erm
(B). Over this period, an important increase in the rate of
erm
-positive isolates was observed: 2% in 2018 compared with 13% in 2023, with 10% for
erm
(N) and 3% for
erm
(B).
erm
(N) has been found exclusively within a CRISPR–Cas9 operon, whereas
erm
(B) has been found within diverse types of resistance genomic islands. Each
erm
(N)- or
erm
(B)-positive isolate had at least two other resistance markers (mostly ciprofloxacin, tetracycline, or ampicillin) and often carried aminoglycoside-associated resistance genes. The majority of the
erm
-positive isolates were obtained from chicken. The increasing rates of
erm
-positive and multiresistant isolates make the monitoring of erythromycin-resistant
Campylobacter
strains, specifically within the chicken meat production, a topic of serious importance.
Microbial hauberks: composition and function of surface layer proteins in gammaproteobacterial methanotrophs
Authors: Hamilton Richard , Gebbie William , Bowman Chynna , Mantanona Alex , Kalyuzhnaya Marina G.
Published: December 2024

Many species of proteobacterial methane-consuming bacteria (methanotrophs) form a hauberk-like envelope represented by a surface (S-) layer protein (SLP) matrix. While several proteins were predicted to be associated with the cell surface, the composition and function of the hauberk matrix remained elusive. Here, we report the identification of the genes encoding the hauberk-forming proteins in two gamma-proteobacterial (Type I) methanotrophs,
Methylotuvimicrobium buryatense
5GB1 (EQU24_15540) and
Methylotuvimicrobium alcaliphilum
20Z
R
(MEALZ_0971 and MEALZ_0972). The proteins share 40% amino acid (AA) sequence identity with each other and are distantly related to the RsaA proteins from
Caulobacter crescentus
(20% AA sequence identity). Deletion of these genes resulted in loss of the characteristic hauberk pattern on the cell surface. A set of transcriptional fusions between the MEALZ_0971 and a superfolder green fluorescent protein (sfGFP) further confirmed its surface localization. The functional roles of the hauberk and cell-surface-associated proteins, including MEALZ_0971, MEALZ_0972, EQU24_15540, and a copper-induced CorA protein, were further investigated via gene expression studies and phenotypic tests. The hauberk core protein of
M. alcaliphilum
20Z
R
showed constitutive expression across 18 growth conditions with reduced growth at high salinity, high methanol, and metal-limited conditions, suggesting a role in cell-envelope stability and metal scavenging. Overall, understanding the genetics, composition, and cellular functions of S-layers contributes to our knowledge of methanotroph adaptation to environmental perturbations and opens a promising prospect for (nano)biotechnology applications.

IMPORTANCE

Understanding the genetics, composition, and cellular functions of the cell envelope proteins, such as S-layers, contributes to our knowledge of microbial cell biology and stress responses and molecular adaptations to environmental perturbations. In addition, this study opens a promising prospect for (nano)biotechnology applications of methane-derived self-assembling protein materials.
Genomic and metabolic characterization of
Trueperella pyogenes
isolated from domestic and wild animals
Authors: Magossi Gabriela , Gzyl Katherine E. , Holman Devin B. , Nagaraja T. G. , Amachawadi Raghavendra , Amat Samat
Published: December 2024

Trueperella pyogenes
is an important bacterial pathogen implicated in infections such as mastitis, metritis, pneumonia, and liver abscesses in both domestic and wild animals, as well as endocarditis and prosthetic joint infections in humans. Understanding the genomic and metabolic features that enable
T. pyogenes
to colonize different anatomical sites within a host and its inter-kingdom transmission and survival is important for the effective control of this pathogen. We employed whole-genome sequencing, phenotype microarrays, and antimicrobial susceptibility testing to identify genomic, metabolic and phenotypic features, and antimicrobial resistance (AMR) genes in
T. pyogenes
recovered from different livestock, companion, and wildlife animals. For comparative genomic analysis, 83
T. pyogenes
genomes, including 60 isolated in the current study and 23 publicly available genomes were evaluated. These genomes represented
T. pyogenes
strains originating from 16 different body sites of 11 different animal hosts (e.g., cattle, swine, ovine, deer, bison, horse, chamois, and cat). Additionally, 49
T. pyogenes
isolates (cattle, sheep, deer, swine, and cats) were evaluated for phenotypic AMR using disk diffusion, and for metabolic profiling using the Biology GENIII MicroPlates. The
T. pyogenes
strains were found not to be host- or body site-specific. The presence of conserved virulence genes (
plo
and
fimA
), as well as genotypic and phenotypic AMR may contribute to the ability of
T. pyogenes
to cause infections in livestock, wildlife, and pets. Most of the tested isolates metabolized diverse carbon sources and chemical compounds, suggesting that this metabolic versatility may enhance the survival, competitiveness, and pathogenic potential of
T. pyogenes
.

IMPORTANCE

Trueperella pyogenes
is an important animal pathogen with zoonotic potential, posing a significant health concern to both animals and humans due to its ability to cause infections across different animal host species and tissues. Current understanding of this pathogen’s adaptability and survival mechanisms is limited. Here, we evaluated the genomic, virulence, metabolic, and antimicrobial resistance (AMR) characteristics of
T. pyogenes
recovered from 16 different body sites of 11 different animal hosts (livestock, companion, and wild animals). We identified multiple AMR and virulence genes that may enable
T. pyogenes
for sustained infection and transmission. Additionally,
T. pyogenes
strains displayed metabolic versatility which could also contribute to its ability to thrive in diverse environments. Understanding the genomic and metabolic, and AMR characteristics that enable
T. pyogenes
to colonize different anatomical sites within a host and its transmission between different animal species is important for the effective control of this pathogen.
Novel inhibition of
Staphylococcus aureus
sortase A by plantamajoside: implications for controlling multidrug-resistant infections
Authors: Chen Yujia , Li Wei , Wang Li , Wang Bingmei , Suo Jian
Published: December 2024

In confronting the significant challenge posed by multidrug-resistant (MDR) pathogens, particularly methicillin-resistant
Staphylococcus aureus
(MRSA), the development of innovative anti-infective strategies is essential. Our research focuses on sortase A (SrtA), a vital enzyme for anchoring surface proteins in
S. aureus
. We discovered that plantamajoside (PMS), a phenylpropanoid glycoside extracted from
Plantago asiatica L
. (Plantaginaceae), acts as an effective and reversible inhibitor of SrtA, with a notable IC
50
value of 22.93 µg/mL. This breakthrough provides a novel approach to combat both resistance and virulence in MRSA. PMS significantly inhibits
S. aureus
adhesion to fibrinogen, reducing biofilm formation and hindering the anchoring of staphylococcal protein A to the cell wall. Live-dead cell assays demonstrated increased survival rates in PMS-treated MRSA-infected A549 cells. Fluorescence quenching experiments revealed a robust interaction between PMS and SrtA, with mechanistic analyses pinpointing the critical R197 amino acid residue as the target site.
In vivo
, PMS was highly effective in a
Galleria mellonella
infection model, reducing mortality rates in MRSA-infected larvae. Additionally, PMS demonstrated therapeutic efficacy in a mouse pneumonia model, improved survival rates, reduced the bacterial load in pulmonary tissues, and mitigated lung damage. These results validate PMS as a promising compound to mitigate MRSA virulence and thwart resistance by targeting SrtA. This study highlights PMS as a leading candidate for controlling MRSA infections, showing the potential of targeting specific bacterial mechanisms in the fight against MDR infections.

IMPORTANCE

The increasing issue of antibiotic resistance, particularly in methicillin-resistant
Staphylococcus aureus
(MRSA), demands innovative solutions. Our study presents plantamajoside (PMS) as a novel inhibitor of sortase A (SrtA), a key enzyme in
S. aureus
pathogenicity. By targeting SrtA, PMS shows promise in curbing the ability of MRSA to adhere, invade, and form biofilms, thereby reducing its virulence without exerting selective pressure for resistance. This research is significant because it introduces a potential new strategy in the antimicrobial arsenal, aligning with the global effort to combat drug-resistant infections. This study is crucial because it identifies a natural compound that can reduce the harmful effects of MRSA, a type of bacteria that is very hard to treat owing to resistance to many antibiotics. This discovery could lead to new treatments that are less likely to cause bacteria to become resistant, which is a major win in the fight against infections that are difficult to cure.
Are we serologically prepared against an avian influenza pandemic and could seasonal flu vaccines help us?
Authors: Sanz-Muñoz Iván , Sánchez-Martínez Javier , Rodríguez-Crespo Carla , Concha-Santos Corina S. , Hernández Marta , Rojo-Rello Silvia , Domínguez-Gil Marta , Mostafa Ahmed , Martinez-Sobrido Luis , Eiros Jose M. , Nogales Aitor
Published: December 2024

The current situation with H5N1 highly pathogenic avian influenza virus (HPAI) is causing a worldwide concern due to multiple outbreaks in wild birds, poultry, and mammals. Moreover, multiple zoonotic infections in humans have been reported. Importantly, HPAI H5N1 viruses with genetic markers of adaptation to mammals have been detected. Together with HPAI H5N1, avian influenza viruses H7N9 (high and low pathogenic) stand out due to their high mortality rates in humans. This raises the question of how prepared we are serologically and whether seasonal vaccines are capable of inducing protective immunity against these influenza subtypes. An observational study was conducted in which sera from people born between years 1925–1967, 1968–1977, and 1978–1997 were collected before or after 28 days or 6 months post-vaccination with an inactivated seasonal influenza vaccine. Then, hemagglutination inhibition, viral neutralization, and immunoassays were performed to assess the basal protective immunity of the population as well as the ability of seasonal influenza vaccines to induce protective responses. Our results indicate that subtype-specific serological protection against H5N1 and H7N9 in the representative Spanish population evaluated was limited or nonexistent. However, seasonal vaccination was able to increase the antibody titers to protective levels in a moderate percentage of people, probably due to cross-reactive responses. These findings demonstrate the importance of vaccination and suggest that seasonal influenza vaccines could be used as a first line of defense against an eventual pandemic caused by avian influenza viruses, to be followed immediately by the use of more specific pandemic vaccines.

IMPORTANCE

Influenza A viruses (IAV) can infect and replicate in multiple mammalian and avian species. Avian influenza virus (AIV) is a highly contagious viral disease that occurs primarily in poultry and wild water birds. Due to the lack of population immunity in humans and ongoing evolution of AIV, there is a continuing risk that new IAV could emerge and rapidly spread worldwide, causing a pandemic, if the ability to transmit efficiently among humans was gained. The aim of this study is to analyze the basal protection and presence of antibodies against IAV H5N1 and H7N9 subtypes in the population from different ages. Moreover, we have evaluated the humoral response after immunization with a seasonal influenza vaccine. This study is strategically important to evaluate the level of population immunity that is a major factor when assessing the impact that an emerging IAV strain would have, and the role of seasonal vaccines to mitigate the effects of a pandemic.
Genome sequence of bovine herpesvirus 5 (BoHV-5) isolate from India
Authors: Verma Assim , Kamboj Himanshu , Khandelwal Nitin , Kumar Ram , Riyesh Thachamvally , Kumar Naveen
Published: December 2024

Recently, we identified bovine herpesvirus 5 (BoHV-5) in a vaginal swab from aborted cattle. It was unusual in two aspects: first, its association with abortion (it is otherwise mainly associated with encephalitis), and second, it is the first report from India (as it is mostly restricted to South American countries). In this study, we conducted the genome sequencing of the BoHV-5 isolate and provided insights into its phylogenetic relationships with other BoHV-5 strains. These findings contribute valuable knowledge toward understanding the epidemiology and evolution of BoHV-5.
A thermodynamic bottleneck in the TCA cycle contributes to acetate overflow in
Staphylococcus aureus
Authors: Shahreen Nabia , Ahn Jongsam , Alsiyabi Adil , Chowdhury Niaz Bahar , Shinde Dhananjay , Chaudhari Sujata S. , Bayles Kenneth W. , Thomas Vinai C. , Saha Rajib
Published: December 2024

During aerobic growth,
S. aureus
relies on acetate overflow metabolism, a process where glucose is incompletely oxidized to acetate, for its bioenergetic needs. Acetate is not immediately captured as a carbon source and is excreted as waste by cells. The underlying factors governing acetate overflow in
S. aureus
have not been identified. Here, we show that acetate overflow is favored due to a thermodynamic bottleneck in the TCA cycle specifically involving the oxidation of succinate to fumarate by succinate dehydrogenase. This bottleneck reduces flux through the TCA cycle, making it more efficient for
S. aureus
to generate ATP via acetate overflow metabolism. Additionally, the protein allocation cost of maintaining ATP flux through the restricted TCA cycle is greater than that of acetate overflow metabolism. Finally, we show that the TCA cycle bottleneck provides
S. aureus
the flexibility to redirect carbon toward maintaining redox balance through lactate overflow when oxygen becomes limiting, albeit at the expense of ATP production through acetate overflow. Overall, our findings suggest that overflow metabolism offers
S. aureus
distinct bioenergetic advantages over a thermodynamically constrained TCA cycle, potentially supporting its commensal–pathogenic lifestyle.
Fish oil and vitamin D in pregnancy for the prevention of early childhood asthma: study protocol for two double-blinded, randomised controlled trials
Authors: Brustad Nicklas , Vahman Nilo , Ralfkiaer Ulrik , Mikkelsen Marianne , Brandt Sarah , Kyvsgaard Julie Nyholm , Vinding Rebecca , Stokholm Jakob , Chawes Bo , Bønnelykke Klaus
Published: December 2024

Introduction

Previous randomised controlled trials (RCTs) have indicated a protective role of pregnancy supplementation with fish oil and high-dose vitamin D, respectively, on offspring asthma, infections and several other disorders in early childhood. However, current evidence is not considered sufficient for recommending these supplements in pregnancy. In two RCTs, we aim to investigate whether these protective effects can be confirmed in larger trials with the goal of changing clinical practice and improving child health.

Methods and analysis

Randomisation of 4000 pregnant women to either (1) (n=2000) the fish oil trial of 2.4 g/day (55% eicosapentaenoic acid (EPA) and 37% docosahexaenoic acid (DHA)) in triacylglycerol form versus placebo or (2) (n=2000) the vitamin D trial of high-dose (3200 IU/day) vitamin D versus placebo on top of the recommended 400 IU/day. Supplementation begins in gestational week 24 (22–26) until 1 week after delivery. Allocation to the trials will be determined based on the preinterventional maternal blood levels of EPA+DHA with a dried blood screening test. Women with low levels (below 4.7% of total fatty acids) will be assigned to the fish oil RCT, and women with high levels will be assigned to the vitamin D RCT. Maternal blood will be used for genetic, metabolomic and proteomic profiling. A 3-year follow-up of the children with longitudinal registration of parent-reported symptoms, diagnoses, medication use and hospitalisations will be performed. The primary outcome is persistent wheeze or asthma until age 3 years, with predefined analyses of effect modification by maternal genotypes. Secondary outcomes are lower respiratory tract infections, gastrointestinal infections, croup, troublesome lung symptoms, eczema, allergy, bone fractures, developmental milestones, mental health, cognition and growth until age 3 years. A follow-up on both primary and secondary outcomes is planned after unblinding, from age 3–6 years.

Ethics and dissemination

The RCTs are approved by the Danish local ethics committee (H-23055833). The studies are registered at ClinicalTrials.gov (NCT06560255andNCT06570889). Study results will be communicated to the medical community, including publications in peer-reviewed journals. All results will be published and available onwww.copsac.com.

Trial registration number

NCT06560255andNCT06570889.
Oesophageal pH testing: everything you wanted to know but were too afraid to ask
Authors: Norton Benjamin Charles , Zarate-Lopez Natalia
Published: December 2024

Reflux of gastric content into the oesophagus is a normal physiological phenomenon, but in the context of troublesome symptoms including heartburn, regurgitation and/or oesophageal chest pain, it is denoted gastro-oesophageal reflux disease (GORD). Unfortunately, many patients do not respond adequately to acid suppression therapy leading to overprescription of proton pump inhibitors (PPIs), major healthcare costs and reduced quality of life. Most patients with reflux have a normal endoscopy, which means oesophageal pH testing becomes critical to determine the role of reflux on symptoms. Oesophageal pH testing can be catheter-based or wireless, and modern impedance catheters provide additional adjunctive information to support the diagnosis. In this educational review, we cover the fundamental aspects of when, how and why to organise oesophageal pH testing. We then discuss how testing is used to determine reflux phenotypes, which in turn are essential to guide clinical decision-making in the management of PPI-refractory GORD.
Targeted screening of at-risk patients with chronic heartburn using a non-endoscopic capsule sponge device can enhance the detection of Barrett’s oesophagus
Authors: Norton Benjamin Charles , Telese Andrea , Papaefthymiou Apostolis , Duku Margaret , Murray Charles , Johnson Gavin , Murino Alberto , Cohen Richard , Lorenz Robert R , Haidry Rehan
Published: December 2024

Introduction

Chronic heartburn from acid reflux can lead to Barrett’s oesophagus (BE), which in turn may predispose to oesophageal adenocarcinoma (OAC). The 5-year survival for OAC remains poor, but earlier identification improves outcomes. Swallowable non-endoscopic capsule sponge tests (eg, EndoSign) have been investigated to aid early diagnosis as a screening tool.

Methods

In February 2024, Heartburn Cancer UK (HCUK) charity in collaboration with Cleveland Clinic London launched a campaign to raise awareness on chronic heartburn and OAC. Members of the public with chronic heartburn were invited to self-refer using an online screening tool targeting high-risk individuals. Those eligible were offered EndoSign at a mobile testing unit. Samples were analysed for cellular atypia, trefoil factor 3 and p53. Individuals with cellular abnormalities were invited to undergo gastroscopy for the primary outcome of BE detection.

Results

In total, 78 individuals (mean age 57.1 (SD 9.4), 85.9% male) were invited to undergo EndoSign with 65 confirming. Sixty individuals (92.3%) could swallow the capsule with no detachments or adverse events. Among 54 conclusive results, 12 (22.2%) had positive findings: intestinal metaplasia (n=10), cellular atypia (n=1) and ulceration (n=1). Eleven individuals chose to undergo gastroscopy. BE was detected in eight (14.8%) with a median Prague classification of C2M3. Three had an irregular squamocolumnar junction. There was one BE-associated low-grade dysplasia (1.9%). The positive predictive value for detection of BE was 72.7% (95% CI 43.5 to 91.7%).

Conclusion

Through a targeted charity campaign, capsule sponge testing in an at-risk population can enhance the detection of BE and associated dysplasia.