bluuebunny/crossref_metadata_2025 huggingface dataset:
SMT-738: a novel small-molecule inhibitor of bacterial lipoprotein transport targeting Enterobacteriaceae
Authors: Breidenstein E. B. M. , Khan N. , Duffy T. , Coward C. , Avis T. , Abdulle O. , Li C.-M. , Mason C. S.
Published: December 2023

Carbapenem-resistant
Enterobacteriaceae
(CREs) are described by the Centers for Disease Control as an urgent threat, and there is a critical need for new therapeutic agents able to treat infections caused by these pathogens. Herein, we describe the microbiological profile, the mechanism f action, and the
in vitro
safety as well as the pharmacokinetic (PK)/PD profile of SMT-738, a small molecule belonging to a new chemical class. SMT-738 is active against Enterobacterales [including multi-drug-resistant
Escherichia coli
with 90% of isolates having a minimum inhibitory concentration (MIC
90
) of 1 µg/mL and
Klebsiella pneumoniae
2 µg/mL] and inactive against a broad panel of Gram-negative and Gram-positive pathogens. SMT-738 displays rapid bactericidal activity (2–4 h) and has a low propensity for resistance development (less than ~10
−9
). Characterization of resistant mutants following exposure to SMT-738 identified mutations within the lipoprotein transport complex (LolCDE), a clinically unexploited and essential bacterial molecular target in Gram-negative bacteria. SMT-738 has a promising
in vitro
toxicology profile. Furthermore, PK studies demonstrated that when dosed intravenously, SMT-738 maintained exposure levels across infection sites (bloodstream/urinary tract/lung). Proof-of-concept studies across multiple murine
in vivo
infection models (bloodstream/pneumonia/urinary tract) demonstrated that SMT-738 significantly reduced the bacterial burden compared to baseline and vehicle control. SMT-738 represents a promising novel drug candidate being developed to address clinically challenging serious life-threatening infections caused by highly resistant
Enterobacteriaceae
including CRE.
Seasonal trends in lysogeny in an Appalachian oak-hickory forest soil
Authors: Jacoby Melaina L. , Hogg Graham D. , Assaad Madeleine R. , Williamson Kurt E.
Published: December 2023

Since 1989, investigations into viral ecology have revealed how bacteriophages can influence microbial dynamics within ecosystems at global scales. Most of the information we know about temperate phages, which can integrate themselves into the host genome and remain dormant via a process called lysogeny, has come from research in aquatic ecosystems. Soil environments remain under-studied, and more research is necessary to fully understand the range of impacts phage infections have on the soil bacteria they infect. The aims of this study were to compare the efficacy of different prophage-inducing agents and to elucidate potential temporal trends in lysogeny within a soil bacterial community. In addition to mitomycin C and acyl-homoserine lactones, our results indicated that halosulfuron methyl herbicides may also be potent inducing agents. In optimizing chemical induction assays, we determined that taking steps to reduce background virus particles and starve cells was critical in obtaining consistent results. A clear seasonal trend in inducible lysogeny was observed in an Appalachian oak-hickory forest soil. The average monthly air temperature was negatively correlated with inducible fraction and burst size, supporting the idea that lysogeny provides a mechanism for phage persistence when temperatures are low and host metabolism is slower. Furthermore, the inducible fraction was negatively correlated with both soil bacterial and soil viral abundance, supporting the idea that lysogeny provides a mechanism for temperate phage persistence when host density is lower. The present study is the first of its kind to reveal clear seasonal trends in inducible lysogeny in any soil.

IMPORTANCE

Lysogeny is a relationship in which certain viruses that infect bacteria (phages) may exist within their bacterial host cell as a segment of nucleic acid. In this state, the phage genome is protected from environmental damage and retains the potential to generate progeny particles in the future. It is thought that lysogeny provides a mechanism for long-term persistence for phages when host density is low or hosts are starved—two conditions likely to be found in soils. In the present study, we provide the first known evidence for a seasonal trend in lysogeny in a forest soil. Based on clear relationships observed between lysogeny, temperature, and soil microbial abundance, we find support for previous hypotheses regarding the factors governing lysogeny.
RND multidrug efflux transporters: similar appearances, diverse actions
Authors: Pos Klaas Martinus
Published: December 2023

In a recent study by Inga V. Leus, Sean R. Roberts, Anhthu Trinh, Edward W. Yu, and Helen I. Zgurskaya (J Bacteriol, 2023,
https://doi.org/10.1128/jb.00217-23
), it was found that the clinically relevant resistance–nodulation–cell division (RND)-type AdeABC antibiotic efflux pump from
Acinetobacter baumannii
exhibits close communication between its antibiotic binding sites. Alterations in one of them can have far-reaching impacts on the drug translocation pathway. These insights could reshape our understanding of RND-type efflux pump mechanisms.
Flankophile: a bioinformatic pipeline for prokaryotic genomic synteny analysis
Authors: Thorn Alix Vincent , Aarestrup Frank M. , Munk Patrick
Published: December 2023

Analysis of flanking region sequences can be useful when comparing mobile prokaryotic sequences from different bacterial isolates or metagenomes. Here, we report a new bioinformatics tool, a pipeline called Flankophile, which can analyze flanking regions and sequence variants. The main feature of Flankophile is that it visualizes flanking region synteny and sequence variants in publication-ready plots with distance trees, gene annotations, and metadata. Antimicrobial resistance is a significant threat to human health, and surveillance of the spread of antimicrobial resistance is essential. The study of acquired antimicrobial resistance genes (ARGs) is an obvious use case for Flankophile due to the typically diverse genetic context of the genes. Flanking sequences offer a stronger epidemiological signal than the gene sequence alone. To demonstrate Flankophile, we applied it to 2,057 sequenced bacterial isolates and 273 metagenomes from humans and pigs in Denmark and compared the ARGs found in each host reservoir. Gene variant results showed that just ca. 4% of all unique ARG variants found (
N
= 1,052) were detected in samples from both humans and pigs. Flanking region analysis of ARG variants frequently detected in this study showed multiple examples of genes where the entire 3,000-base pair flanking region was identical in samples from both hosts but also cases where no overlap was observed, and the clustering showed a complete separation of the samples from pigs and the samples from humans.

IMPORTANCE

The Flankophile pipeline enables the analysis and visualization of flanking regions of prokaryotic sequences of interest on large data sets in one step and in a consistent manner. A specific tool for flanking region analysis with automated visualization has not been developed before, and Flankophile will make flanking region analysis easier and accessible to more people. Flankophile will be especially useful in the field of genomic epidemiology of acquired antimicrobial resistance genes. Here, information from flanking region sequences can be instrumental in rejecting or supporting the possibility of a recent common source of the same resistance gene found in different samples.
Antimicrobial combinations against
Helicobacter pylori
including benzoxadiazol-based flavodoxin inhibitors:
in vitro
characterization
Authors: Beyria Lilha , Gourbeyre Ophelie , Salillas Sandra , Mahía Alejandro , Díaz de Villegas María Dolores , Aínsa José Antonio , Sancho Javier , Bousquet-Mélou Alain , Ferran Aude A.
Published: December 2023

Antimicrobial resistance of
Helicobacter pylori
(
Hp
) threatens currently available treatment regimens and prompts the development of antimicrobial drugs against new bacterial targets. One such class of drugs is
Hp
-flavodoxin (
Hp
-fld) inhibitors, which target an essential metabolic pathway in
Hp
. The aim of this study was to characterize the effects of these inhibitors against
Hp
over time when used alone or combined with conventional antibiotics. Four benzoxadiazol-based fld inhibitors were initially tested for their
in vitro
potency, with compound IV displaying the highest efficacy. This compound was then combined with clarithromycin, metronidazole, amoxicillin, levofloxacin, and rifampicin in further experiments. Checkerboard assays indicated that compound IV exhibited additive activity when combined with these antibiotics. The study further investigated the time course of antibacterial effects by exposing a high inoculum of
Hp
to compound IV and each antibiotic, alone or in combination. At just four times the minimum inhibitory concentration, compound IV demonstrated bactericidal effects within 6 h. However, the regrowth of bacteria occurred between 24 and 48 h of exposure. Similar patterns of killing followed by regrowth were observed for conventional antibiotics alone. However, the addition of compound IV to the antibiotics clearly limited regrowth over 72 h. These findings suggest that compound IV can effectively eliminate spontaneous mutants that are resistant to conventional antibiotics or prevent new mutations during drug exposure.
Hp
-fld inhibitors, such as compound IV, hold promise as new drugs to be integrated into
Hp
infection treatment, potentially reducing the development of resistance and shortening the duration of treatment.

IMPORTANCE

The antimicrobial resistance of
Helicobacter pylori
(
Hp
) currently poses a threat to available treatment regimens. Developing antimicrobial drugs targeting new bacterial targets is crucial, and one such class of drugs includes
Hp
-flavodoxin (
Hp
-fld) inhibitors that target an essential metabolic pathway in
Hp
. Our study demonstrated that combining these new drugs with conventional antibiotics used for
Hp
infection treatment prevented the regrowth observed with drugs used alone.
Hp
-fld inhibitors show promise as new drugs to be incorporated into the treatment of
Hp
infection, potentially reducing the development of resistance and shortening the treatment duration.
Targeted amplification and genetic sequencing of the severe acute respiratory syndrome coronavirus 2 surface glycoprotein
Authors: Keller Matthew W. , Keong Lisa M. , Rambo-Martin Benjamin L. , Hassell Norman , Lacek Kristine A. , Wilson Malania M. , Kirby Marie K. , Liddell Jimma , Owuor D. Collins , Sheth Mili , Madden Joseph , Lee Justin S. , Kondor Rebecca J. , Wentworth David E. , Barnes John R.
Published: December 2023

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein is a highly immunogenic and mutable protein that is the target of vaccine prevention and antibody therapeutics. This makes the encoding S-gene an important sequencing target. The SARS-CoV-2 sequencing community overwhelmingly adopted tiling amplicon-based strategies for sequencing the entire genome. As the virus evolved, primer mismatches inevitably led to amplicon dropout. Given the exposure of the spike protein to host antibodies, mutation occurred here most rapidly, leading to amplicon failure over the most insightful region of the genome. To mitigate this, we developed a targeted method to amplify and sequence the S-gene. We evaluated 20 distinct primer designs through iterative
in silico
and
in vitro
testing to select the optimal primer pairs and run conditions. Once selected, periodic
in silico
analysis monitors primer conservation as SARS-CoV-2 evolves. Despite being designed during the beta wave, the selected primers remain >99% conserved through Omicron as of 19 October 2023. To validate the final design, we compared targeted S-gene data to National SARS-CoV-2 Strain Surveillance whole-genome data for 321 matching samples. Consensus sequences for the two methods were highly identical (99.998%) across the S-gene. This method can serve as a complement to whole-genome surveillance or can be leveraged where only S-gene sequencing is of interest.

IMPORTANCE

The COVID-19 pandemic was accompanied by an unprecedented surveillance effort. The resulting data were and will continue to be critical for surveillance and control of SARS-CoV-2. However, some genomic surveillance methods experienced challenges as the virus evolved, resulting in incomplete and poor quality data. Complete and quality coverage, especially of the S-gene, is important for supporting the selection of vaccine candidates. As such, we developed a robust method to target the S-gene for amplification and sequencing. By focusing on the S-gene and imposing strict coverage and quality metrics, we hope to increase the quality of surveillance data for this continually evolving gene. Our technique is currently being deployed globally to partner laboratories, and public health representatives from 79 countries have received hands-on training and support. Expanding access to quality surveillance methods will undoubtedly lead to earlier detection of novel variants and better inform vaccine strain selection.
Microbial network and fermentation modulation of Napier grass and sugarcane top silage in southern Africa
Authors: Du Zhumei , Yamasaki Seishi , Oya Tetsuji , Nguluve Damiao , Euridse Denise , Tinga Benedito , Macome Felicidade , Cai Yimin
Published: December 2023

To effectively alleviate the shortage of animal feed in the tropics, we applied a screening lactic acid bacteria (LAB) strain (
Lactiplantibacillus plantarum
MO1) and a commercial inoculant (
L. plantarum
LP1) to prepare silage from early flowering Napier grass and after harvest sugarcane tops in southern Africa. The microbial community structure, co-occurrence network, and fermentation characteristics of silage were analyzed using PacBio single-molecule real-time sequencing technology. Strain MO1, isolated from corn silage, was characterized by strong acid tolerance and the ability to produce lactic acid. Before ensiling, the dominant microbial community in both Napier grass and sugarcane top were Gram-negative harmful microbes. After ensiling, the main microbial community shifted from Gram-negative to Gram-positive bacteria, and the microbial alpha diversity of all silages significantly decreased (
P
< 0.05). Compared to the control, fermentation of the LAB-treated silages was accelerated and
L. plantarum
became the dominant microbial community, while the lactic acid content increased (
P
< 0.05) and the pH was reduced (
P
< 0.05). In the MO1-treated silages, the relative abundance of LAB was markedly increased and formed a co-occurrence microbial network with
L. plantarum
as the dominant microorganism. It also led to the global and overview maps, as a special class of metabolic pathways in the Kyoto Encyclopedia of Genes and Genomes database was enhanced and the carbohydrate metabolism and amino acid metabolism pathways were weakened, thereby improving the flavor and quality of the silages compared to the LP1-treated ones. Strain MO1 can modulate the microbial community and metabolic pathways and achieve clean fermentation. It is of great significance to alleviate feed shortage and promote sustainable production of livestock.

IMPORTANCE

Feed shortage in the tropics is a major constraint to the production of livestock products such as milk and meat. In order to effectively utilize of local feed resources, the selected lactic acid bacteria (LAB) strain was used to prepare Napier grass and sugarcane top silage. The results showed that the two silages inoculated with LAB formed a co-occurrence microbial network dominated by
Lactiplantibacillus
during the fermentation process, regulated the microbial community structure and metabolic pathways, and improved the silage fermentation quality. This is of great significance for alleviating feed shortage and promoting sustainable production of livestock.
Strangulated bowel obstruction caused by vaginal perforation due to vaginal cancer in a patient with chronic uterine prolapse
Authors: Fukai Shota , Maeda Shimpei , Chikazawa Kenro , Rikiyama Toshiki
Published: December 2023

A woman in her 90s with chronic uterine prolapse presented with abdominal pain and a vaginal mass. The patient had generalised peritonitis and a strangulated bowel obstruction originating from a perforated posterior vagina. We performed partial intestinal resection and a total hysterectomy, including excision of the perforation of the vaginal site and the adnexa. The patient died on postoperative day 8 due to worsening systemic sepsis. The pathological diagnosis revealed an invasive carcinoma in the perforated area of the vagina. Obstetric factors are the most frequent cause of female genital tract perforation, and chronic uterine prolapse is associated with this condition; however, vaginal cancer has never been reported as a cause of perforation. Therefore, close collaboration in gynaecology should be considered to investigate whether vaginal perforation and uterine prolapse are related to cancer.
Endometriosis with colonic mucosal colonisation: a diagnostic confounder
Authors: Adler Jeremy , Algashaamy Khaled , Garcia de Buitrago Monica T , Pinto Andre , Montgomery Elizabeth Anne
Published: December 2023

Aims

Secondary mucosal colonisation by a carcinoma originating from a distant site is a pattern of metastasis to the intestines and hepatobiliary tract and a mimic of primary neoplasia. Although endometriosis is considered benign, its ability to spread widely underscores its quasi-neoplastic nature. After noting that endometriotic glands can colonise the colonic mucosa along the basement membrane, mimicking metastatic disease, we conducted an intradepartmental review of intestinal specimens showing endometriosis obtained from 2016 to 2023 to characterise and quantify the incidence of this phenomenon.

Methods

Material from 38 lower gastrointestinal specimens with a primary or ancillary diagnosis of endometriosis was identified from our surgical pathology database. Slides were reviewed, documenting the extent and micro-anatomic location affected by endometriosis, with a focus on identifying examples showing mucosal colonisation.

Results

The most common site of involvement was the distal colon (23 cases; 11 of rectum, 9 of sigmoid colon and 3 of rectosigmoid) followed by the appendix (N=10), cecum (N=2), small intestine (N=2) and ‘colon not otherwise specified’ (N=1). Mucosal involvement was identified in eight cases (21%), half of which demonstrated seamless colonisation of the epithelium by endometriotic glands. In two of these, the procedure was prompted by the presence of a rectal mass or stricture with concern for malignancy.

Conclusion

Endometriosis occasionally (4/38; 10.5%) colonises colonic epithelium, potentially mimicking a metastasis or intraepithelial neoplasia/dysplasia. Although unusual, this phenomenon was observed in half of specimens from patients with mucosal involvement in whom a mass or stricture suggested malignancy, a potentially misleading pattern of endometriosis.
Potential contribution of vaccination uptake to occupational differences in risk of SARS-CoV-2: analysis of the ONS COVID-19 Infection Survey
Authors: Rhodes Sarah , Demou Evangelia , Wilkinson Jack , Cherrie Mark , Edge Rhiannon , Gittins Matthew , Katikireddi Srinivasa Vittal , Kromydas Theocharis , Mueller William , Pearce Neil , van Tongeren Martie
Published: December 2023

Objectives

To assess variation in vaccination uptake across occupational groups as a potential explanation for variation in risk of SARS-CoV-2 infection.

Design

We analysed data from the UK Office of National Statistics COVID-19 Infection Survey linked to vaccination data from the National Immunisation Management System in England from 1 December 2020 to 11 May 2022. We analysed vaccination uptake and SARS-CoV-2 infection risk by occupational group and assessed whether adjustment for vaccination reduced the variation in risk between occupational groups.

Results

Estimated rates of triple vaccination were high across all occupational groups (80% or above), but were lowest for food processing (80%), personal care (82%), hospitality (83%), manual occupations (84%) and retail (85%). High rates were observed for individuals working in health (95% for office based, 92% for those in patient-facing roles) and education (91%) and office-based workers not included in other categories (90%). The impact of adjusting for vaccination when estimating relative risks of infection was generally modest (ratio of hazard ratios across all occupational groups reduced from 1.37 to 1.32), but was consistent with the hypothesis that low vaccination rates contribute to elevated risk in some groups.

Conclusions

Variation in vaccination coverage might account for a modest proportion of occupational differences in infection risk. Vaccination rates were uniformly very high in this cohort, which may suggest that the participants are not representative of the general population. Accordingly, these results should be considered tentative pending the accumulation of additional evidence.
A Graph-Based Neural Approach to Linear Sum Assignment Problems
Authors: Aironi Carlo , Cornell Samuele , Squartini Stefano
Published: December 2023

Linear assignment problems are well-known combinatorial optimization problems involving domains such as logistics, robotics and telecommunications. In general, obtaining an optimal solution to such problems is computationally infeasible even in small settings, so heuristic algorithms are often used to find near-optimal solutions. In order to attain the right assignment permutation, this study investigates a general-purpose learning strategy that uses a bipartite graph to describe the problem structure and a message passing Graph Neural Network (GNN) model to learn the correct mapping. Comparing the proposed structure with two existing DNN solutions, simulation results show that the proposed approach significantly improves classification accuracy, proving to be very efficient in terms of processing time and memory requirements, due to its inherent parameter sharing capability. Among the many practical uses that require solving allocation problems in everyday scenarios, we decided to apply the proposed approach to address the scheduling of electric smart meters access within an electricity distribution smart grid infrastructure, since near-real-time energy monitoring is a key element of the green transition that has become increasingly important in recent times. The results obtained show that the proposed graph-based solver, although sub-optimal, exhibits the highest scalability, compared with other state-of-the-art heuristic approaches. To foster the reproducibility of the results, we made the code available at https://github.com/aircarlo/GNN_LSAP .
Search for new physics in semileptonic decays of K and B as implied by the g−2 anomaly in FSM
Authors: Bordes José , Chan Hong-Mo , Tsou Sheung Tsun
Published: December 2023

The framed standard model (FSM), constructed to explain, with some success, why there should be three and apparently only three generations of quarks and leptons in nature falling into a hierarchical mass and mixing pattern, 10 suggests also, among other things, a scalar boson U, with mass around 17 MeV and small couplings to quarks and leptons, 11 which might explain 9 the [Formula: see text] anomaly reported in experiment. 12 The U arises in FSM initially as a state in the predicted “hidden sector” with mass around 17[Formula: see text]MeV, which mixes with the standard model (SM) Higgs [Formula: see text], acquiring thereby a coupling to quarks and leptons and a mass just below 17[Formula: see text]MeV. The initial purpose of this paper is to check whether this proposal is compatible with experiment on semileptonic decays of Ks and Bs where the U can also appear. The answer to this we find is affirmative, in that the contribution of U to new physics as calculated in the FSM remains within the experimental bounds, but only if [Formula: see text] lies within a narrow range just below the unmixed mass. As a result from this, one has an estimate [Formula: see text]–17[Formula: see text]MeV for the mass of U, and from some further considerations the estimate [Formula: see text][Formula: see text]eV for its width, both of which may be useful for an eventual search for it in experiment. If found, it will be, for the FSM, not just the discovery of a predicted new particle, but the opening of a window into a whole “hidden sector” containing at least some, perhaps even the bulk, of the dark matter in the universe.
Kernel-Induced Matriarch Path Tracking Elephant Herding Optimization Technique for Identification and Classification of Cancer Types Using Support Vector Machines
Authors: Senbagamalar L. , Logeswari S.
Published: December 2023

Abnormal cells in the human body that keep on mutating are termed to be cancer in medical terms. There are multiple types of cancer identified in human beings. It is very much essential to identify and classify the type of cancer in its earlier stage. This objective can be satisfied by artificial intelligence which has a subfield of machine learning to create a generalized model that could identify and classify cancer with increased performance. To perform the identification and classification of various cancer types, in this paper, two techniques are adopted. The optimized feature set computation was done using the Kernel-Induced Matriarch path tracking Elephant Herding Optimization (KIM-EHO) and the classification for the given samples was done using the Support Vector Machines (SVM). The proposed techniques are implemented with the benchmark datasets and the results proved that the proposed methodologies outperformed the existing methods in terms of accuracy, specificity, sensitivity and time complexity.
Deep Residual Network with Pelican Cuckoo Search for Traffic Sign Detection
Authors: T. Kumaravel , P. Natesan
Published: December 2023

The timely and precise discovery of traffic signs is considered an effective part of modeling automated vehicle driving. However, the dimension of traffic signs accounted for a lower ratio of input pictures which elevated the complexity of discovery. Hence, a new model is devised using faster region-based convolution neural network (faster R-CNN) traffic for detecting traffic signs. The Region of Interest (RoI) extraction and Median filter are executed for discarding the superfluous data from the dataset. The method extracted a Pyramid Histogram of Oriented Gradient (PHoG), local vector pattern (LVP), CNN and ResNet features for generating beneficial information. It is used to lessen the loss of contextual data and the data augmentation is further applied for making the training of the model more stable and time-saving. The traffic sign recognition is executed with faster R-CNN wherein the tuning of hyperparameters such as batch normalization rate, epoch and learning rate is determined by the proposed pelican cuckoo search (PCS). The method revealed improved efficacy without presenting additional computational costs in the model. Moreover, the faster R-CNN is termed the finest technique to enhance the discovery of traffic signs. The proposed PCS-based faster R-CNN outperformed with the highest precision 92.7%, specificity of 93.7% and [Formula: see text]-measure of 93.2%.
Person Identification System Using Periocular Biometrics Based on Hybrid Optimal Dense Capsule Network
Authors: Bhamare Deepali R. , Patil Pravin S.
Published: December 2023

Person identification using periocular images has emerged as a challenging scenario in efficient biometric analysis, particularly under less constrained environments. Accurate recognition is significant in rendering effective measures during the COVID-19 pandemic. In this research paper, the person identification process is performed based on a deep learning model. Several effectual methods have already been developed, but certain drawbacks still exist, like deteriorated image quality, high computational cost, increased error, less training ability, a requirement of high storage space and accuracy rate degradation. Hence, the proposed work introduces a Hybrid Optimal Dense Capsule network-based Periocular biometric system (HodCP) to conquer these demerits. The proposed work involves pre-processing, dimensionality reduction, hybrid feature extraction and Image matching. The pre-processing step is undertaken using Parabolic Contrast Enhancement (PCE) to balance the image contrast and enhance the image quality. Then the Two-Dimensional Principal Component Analysis (2D_PCA) is employed to minimize the image dimensionality. Deep features are extracted in the hybrid feature extraction process using Dense Convolutional-121 Capsule Network (DenseCapsNet). The net loss and hyperparameter tuning are performed through African Vultures Optimization (AVO) algorithm. Finally, image matching is performed using Weighted Distance Similarity (WDS), which identifies the similarity between the query image and a set of image samples based on the distance score. The simulation tool used for analyzing better performance is PYTHON. The data required to process the proposed work are collected from four benchmark datasets. The proposed work provides a better accuracy rate of CASIA-Iris-Mobile-V1.0 (99.01%), UBIPr (99.12%), Facemask detection dataset (98.67%) and Glasses versus without glasses dataset (98.83%), which is superior to the existing methods.
Limit Cycles of a Planar Piecewise Linear System with an Improper Node
Authors: Xiao Ning , Wu Kuilin
Published: December 2023

This paper is concerned with the number of limit cycles for a planar piecewise linear (PWL) system with two zones separated by a straight line. Assume that one of the subsystems of the PWL system has an improper node. The number of limit cycles for saddle-improper node type, focus-improper node type and center-improper node type (the focus or the center is a virtual or boundary equilibrium) are studied. First, we introduce displacement functions and study the number of zeros of displacement functions for different types. Then, we give the parameter regions where the exact number of limit cycles is one or two (at least two) for different types.
A Novel Conservative Chaotic Circuit with a Cubic Root
Authors: Sun Changchun , He Kai , Xu Qicheng , Zhang Xinguo
Published: December 2023

A new conservative chaotic system with a cubic root is constructed in this paper. The system has no equilibria. An offset parameter is introduced into the system. By modulating different offset parameters and corresponding initial conditions, multiple coexisting conservative chaotic attractors can be generated consequently. By replacing the offset parameter with an appropriate sign function, multiscroll conservative chaotic attractors can be generated effectively by connecting multiple coexisting chaotic attractors based on offset boosting. Moreover, the number of scrolls tend to be infinite. Finally, a novel chaotic circuit with a cubic root is designed successfully by connecting two multipliers in opposite directions. The hardware implementation of the chaotic circuit is also completed to further verify the existence of conservative chaos and the consistency with the numerical simulations.
Periodic Center Manifolds for Nonhyperbolic Limit Cycles in ODEs
Authors: Lentjes Bram , Windmolders Mattias , Kuznetsov Yuri A.
Published: December 2023

In this paper, we deal with a classical object, namely, a nonhyperbolic limit cycle in a system of smooth autonomous ordinary differential equations. While the existence of a center manifold near such a cycle was assumed in several studies on cycle bifurcations based on periodic normal forms, no proofs were available in the literature until recently. The main goal of this paper is to give an elementary proof of the existence of a periodic smooth locally invariant center manifold near a nonhyperbolic cycle in finite-dimensional ordinary differential equations by using the Lyapunov–Perron method. In addition, we provide several explicit examples of analytic vector fields admitting (non)-unique, (non)-[Formula: see text]-smooth and (non)-analytic periodic center manifolds.
Grazing-Induced Dynamics of the Piecewise-Linear Chua’s Circuit
Authors: Fu Shihui , Chávez Joseph Páez , Lu Qishao
Published: December 2023

In this paper, we consider the piecewise-linear Chua’s circuit, which is well known for its rich variety of bifurcation, chaotic and other nonlinear phenomena. Suitable switching boundaries are introduced based on the piecewise-linear representation of Chua’s diode. In this way, we derive analytical conditions for a grazing bifurcation to occur, when one or two families of periodic orbits have a zero-velocity contact with the switching boundaries. In connection to this phenomenon, we also study the focus-center-limit cycle bifurcation and its implications regarding the system dynamics, from both analytical and numerical points of view. Furthermore, a detailed parametric study of Chua’s circuit is carried out via path-following techniques for nonsmooth dynamical systems, implemented via the continuation software COCO. This study reveals the presence of codimension-one bifurcations of limit cycles, such as those mentioned above, as well as classical (fold and period-doubling) bifurcations. The analysis confirms the presence of coexisting attractors, which are produced by a hysteresis loop induced by the interaction of a fold and a focus-center-limit cycle bifurcation.
Allocation of Portfolio Risk and Outside Options: Which is the Best Coalition Structure Value to Solve the Low-Risk Anomaly?
Authors: Hiller Tobias
Published: December 2023

In this paper, we enhance the application of coalition structure (CS) games to the distribution of portfolio risk across individual assets in a portfolio. In a recent paper, CS games were applied for the first time as a risk measure that takes into account the contributions of individual assets to portfolio risk and contributions to the risk of the stock market as a whole. We enhance this approach by using five values for CS games in a simulation study. In this simulation, it can be shown that using CS games has an even higher potential to solve the so-called low-risk puzzle than shown in previous literature.
Simulation of Air Flow Field and Temperature Distribution in the Ward of a Newly-Built Hospital of Post-COVID-19
Authors: Wang Leilei , Xia Jiangling
Published: December 2023

In order to solve the problem of uneven distribution of air conditioning temperature and air velocity in the ward, it is easy to produce the uncomfortable feeling of cold and hot and wind blowing. Taking the standard double room general ward of a newly built hospital as the research object, a mathematical model was established, and CFD software was used to numerically simulate the temperature field and velocity field of the air in the ward, optimize the location of the air outlet, and put forward the suggestion of the optimal installation location of the hospital bed. The results show that when the fan coiler air supply outlet is close to the west wall and the fresh air outlet is far away from the west wall, the inhomogeneity of the distribution of the temperature field and velocity field in the ward is reduced, and at this time, the temperature and velocity distribution of the air in the ward is more uniform, so that the patients’ overall feeling in the ward is more comfortable, and at this time, the installation position of the air outlet is more reasonable; and it is determined that the optimal placement of the beds in the room is at the locations of [Formula: see text] = 2 m, [Formula: see text] = 2.5 m and [Formula: see text] = 2 m, [Formula: see text] = 4.5 m, and at this time the two beds are at the same time, which is more reasonable. When [Formula: see text] = 4.5 m, the temperature difference between the two beds is less than 0.5 K, the wind speed difference is not more than 0.08 m/s, and the velocity gradient direction is the same.
Evaluation of Flexible Electrochromic Device Based on V2 O5 Film Prepared by Electrophoresis
Authors: Huang Shenghuai , Yang Mingqing , Zhang Shiyu , Wang Lei , Niu Chunhui , Lv Yong
Published: December 2023

The red V2O5 sol was prepared by facile alternating stirring and ultrasonic dispersion route. A V2O5 film fabricated on ITO-PET by electrophoresis method was used to demonstrate a flexible electrochromic device. The effects of applied voltage and electrophoresis time for V2O5films were investigated in detail. When the electrophoresis time was kept 30 s, the applied voltage was above 3 V to deposit uniform V2O5-PET film. The electrophoresis time could more significantly regulate the deposition of V2O5 on ITO-PET film. A flexible electrochromic device with “sandwich” structure was fabricated using V2O5 film, and its electrochromic performance of the device was evaluated. The flexible V2O5 electrochromic devices show the multicolor electrochromic performance of yellow, yellow-green, green and orange-red. The coloration efficiency values of V2O5 devices were 21.6 cm2C[Formula: see text] (from initial yellow to green) and 26.9 cm2C[Formula: see text] (from green to orange-red), respectively, and the highest transmittance modulation range was 51% at 741 nm. The work provided a facile and green method for fabrication of flexible V2O5 electrochromic device.
A variational framework for higher order perturbations
Authors: Chiaffredo Federico , Fatibene Lorenzo , Ferraris Marco , Ricossa Emanuele , Usseglio Davide
Published: December 2023

A covariant, global, variational framework for perturbations in field theories is presented. Perturbations are obtained as vertical vector fields on the configuration bundle and they drag, exactly, solution into solutions.

The flow of a perturbation drags solutions into solutions and the dragged perturbed solutions can be expanded in a series with respect to the flow parameter, hence it contains perturbations at any order.

Mechanics is included as a special case. As a simple application, we recover the well-known discussion about stability of geodesics on a sphere [Formula: see text].
Evolution of physical systems and nonlinear realized symmetries
Authors: Cirilo-Lombardo Diego Julio
Published: December 2023

In this work, a new method to determine and to describe the evolution of physical systems (in classical or quantum regimes) is proposed. The main idea is based in the observation that the complete determination of dynamics of the system is connected to the nonlinear realization (NLR) of the symmetry group associated with the symmetry of the Hamiltonian [Formula: see text] of the system. The Maurer–Cartan forms, when they are parametrically associated to the projection on the hypersurface induced by the group in question via pullback, of the Hamiltonian components (based on the generators of the symmetry group by which it is defined) give rise to a fundamental system of equations by which the precise evolution can be determined. Such a system of equations under certain conditions that we will specify in this paper coincides with the system obtained through the Wei–Norman method, thus showing explicitly that our proposal is more general due the universal character of equations from the NLRs approach. As example, the important problem of the Caldirola–Kanai inverted Hamiltonian is completely solved, showing at the same time a new interpretation of what NLRs refer to.
A Distributed Optimization Approach for Collaborative Object Lifting Using Multiple Aerial Robots
Authors: Liu Jinxin , Sun Chao , Feng Zhi , Guan Renhe , Chang Jindong , Hu Guoqiang
Published: December 2023

In the past decade, multi-robot collaborative object transport has garnered significant attention, with the majority of research targeting transport strategies. This study recasts the collaborative object lifting challenge into an optimization problem framework. Within this setup, each robot leverages a local evaluation function to determine its lifting location. Collectively, these robots strive to optimize a unified evaluation function. An intertwined equation constraint is embedded within the optimization schema, ensuring that the system’s mass center remains stable throughout the lifting process. Furthermore, we impose local feasibility constraints, thereby delimiting the optimal lifting location to a specified region. This research introduces several algorithms, differentiated based on the constraints applied to robot velocity. By harnessing these algorithms, robots can autonomously pinpoint the most apt lifting location that aligns with predetermined criteria. This methodology necessitates a robot to engage in exchanges of auxiliary variables solely with its immediate peers. Noteworthily, parameters such as location, velocity, and mass are accessed in a localized manner, reinforcing data privacy and reducing communication burdens. The paper concludes with a robust mathematical validation that underscores asymptotic convergence to the exact optimal lifting location, underpinned by numerical simulations which attest to the potency of the proposed algorithms.
Mechanism and Kinetics of Na2Sx (x ≤ 2) Precipitation in Sodium-Sulfur and Sodium/(Oxygen)-Sulfur Batteries
Authors: Zhang Qipeng , Yang Tairan , Li Zheng
Published: December 2023

Room-temperature sodium-sulfur (RT Na-S) batteries have attracted ever-increasing attention because of their enhanced energy density and low price. Although the performance of RT Na-S batteries is obtained in many other research, the basic mechanism and kinetics have not involved yet, especially in discharge product growth, which affects electrochemical performance. Meanwhile, designed additional redox activities (in the presence of oxygen) could simultaneously suppress sodium polysulfide shuttling and enhance energy density according to our group reported. However, the kinetic study of the intermediate has not been explored. In this work, we discussed the deposition of low-order sodium polysulfide (Na2Sx, x ≤ 2) in different potentials and types of glyme-solvents in Na-S and Na/(O2)-S system. The results show that the morphology of deposition Na2Sx (x ≤ 2) is affected by interfacial energy barrier controlled by overpotentials and the radius of sodium ions, which produced the precipitation of particle shape rather than film. Potentiostatic experiments show the kinetics are elevated in the presence of oxygen. In addition, the exchange current density of different sodium polysulfides was studied. The high-order sodium polysulfide has a lower exchange current density than that of low-order sodium polysulfide in Na-S system, requiring greater driving force, while transformation of the intermediate from high-order oxy-sulfur to low-order oxy-sulfur species require less impulse in Na/(O2)-S systems. This paper provides new understandings of the deposition mechanism and kinetics of Na2Sx (x ≤ 2) Na-S and Na/(O2)-S system in and to choose the appropriate solvent and potential.
Lithium-Ion Cells in Automotive Applications: Tesla 4680 Cylindrical Cell Teardown and Characterization
Authors: Ank Manuel , Sommer Alessandro , Abo Gamra Kareem , Schöberl Jan , Leeb Matthias , Schachtl Johannes , Streidel Noah , Stock Sandro , Schreiber Markus , Bilfinger Philip , Allgäuer Christian , Rosner Philipp , Hagemeister Jan , Rößle Matti , Daub Rüdiger , Lienkamp Markus
Published: December 2023

Battery research depends upon up-to-date information on the cell characteristics found in current electric vehicles, which is exacerbated by the deployment of novel formats and architectures. This necessitates open access to cell characterization data. Therefore, this study examines the architecture and performance of first-generation Tesla 4680 cells in detail, both by electrical characterization and thermal investigations at cell-level and by disassembling one cell down to the material level including a three-electrode analysis. The cell teardown reveals the complex cell architecture with electrode disks of hexagonal symmetry as well as an electrode winding consisting of a double-sided and homogeneously coated cathode and anode, two separators and no mandrel. A solvent-free anode fabrication and coating process can be derived. Energy-dispersive X-ray spectroscopy as well as differential voltage, incremental capacity and three-electrode analysis confirm a NMC811 cathode and a pure graphite anode without silicon. On cell-level, energy densities of 622.4 Wh/L and 232.5 Wh/kg were determined while characteristic state-of-charge dependencies regarding resistance and impedance behavior are revealed using hybrid pulse power characterization and electrochemical impedance spectroscopy. A comparatively high surface temperature of ∼70 °C is observed when charging at 2C without active cooling. All measurement data of this characterization study are provided as open source.
Combined repetitive inhalant endotoxin and collagen-induced arthritis drive inflammatory lung disease and arthritis severity in a testosterone-dependent manner
Authors: Poole Jill A. , Thiele Geoffrey M. , Ramler Elizabeth , Nelson Amy J. , Duryee Michael J. , Schwab Aaron D. , Gleason Angela , Hunter Carlos D. , Gaurav Rohit , Wyatt Todd A. , England Bryant R. , Mikuls Ted R.
Published: December 2023

Our study shows that testosterone acts as a key immunomodulatory hormone contributing to critical features of rheumatoid arthritis (RA)-associated lung disease in the setting of airborne endotoxin (lipopolysaccharide; LPS) exposures and concomitant arthritis induction in mice. The exaggerated airway inflammation observed following combined exposures in male mice was accompanied by increases in profibrotic mediators, netosis, and increased expression of lung autoantigens, all relevant to the pathogenesis of lung disease in arthritis.
The Elusive Hypertrophy of the Python Heart
Authors: Jensen Bjarke , Wang Tobias
Published: December 2023

The Burmese python, one of the world’s largest snakes, has reached celebrity status for its dramatic physiological responses associated with digestion of enormous meals. The meals elicit a rapid gain of mass and function of most visceral organs, particularly the small intestine. There is also a manyfold elevation of oxygen consumption that demands the heart to deliver more oxygen. It therefore made intuitive sense when it was reported that the postprandial response entailed a 40% growth of heart mass that could accommodate a rise in stroke volume. Many studies, however, have not been able to reproduce the 40% growth of the heart. We collated published values on postprandial heart mass in pythons, which include several instances of no change in heart mass. On average, the heart mass is only 15% greater. The changes in heart mass did not correlate to the mass gain of the small intestine or peak oxygen consumption. Hemodynamic studies show that the rise in cardiac output does not require increased heart mass but can be fully explained by augmented cardiac filling and postprandial tachycardia. Under the assumption that hypertrophy is a contingent phenomenon, more recent experiments have employed two interventions such as feeding with a concomitant reduction in hematocrit. The results suggest that the postprandial response of the heart can be enhanced, but the 40% hypertrophy of the python heart remains elusive.