bluuebunny/crossref_metadata_2025 huggingface dataset:
In-Silico Model Validation of Impact on a Composite Helmet Shell
Authors: Jennings Turner , Amini Rouzbeh , Müftü Sinan
Published: May 2024

Numerical impact simulation plays a critical role in the development and improvement of helmet systems. Due to the curvature of the helmet, the selection of impact position on the helmet may affect the ability to correlate results between numerical models and experimental results. In this study, high-velocity impact simulations were performed on composite plates, as well as a model of a modern composite helmet to validate helmet model performance. Results of the composite plate simulation show a non-converging increase in composite deformation with mesh refinement, indicating that model validation is a function of both material properties and mesh selection. Results of impact on the helmet model show that the calculated deformation of the helmet increases by up to 35% with a 20 mm change in impact position. The positional variation of helmet deformation is most pronounced on the front of the helmet. Due to the significant effect that impact position has on helmet deformation, the numerical model validation cannot be performed against experimental tests of a “small” sample size.
Performance Analysis of Liquid-to-Air Heat Exchanger of High-Power Density Racks
Authors: Heydari Ali , Gharaibeh Ahmad R. , Tradat Mohammad , Soud Qusai , Manaserh Yaman , Radmard Vahideh , Eslami Bahareh , Rodriguez Jeremy , Sammakia Bahgat
Published: May 2024

The ability of traditional room-conditioning systems to accommodate expanding information technology loads is limited in contemporary data centers (DCs), where the storage, storing, and processing of data have grown quickly as a result of evolving technological trends and rising demand for online services, which has led to an increase in the amount of waste heat generated by IT equipment. Through the implementation of hybrid air and liquid cooling technologies, targeted, on-demand cooling is made possible by employing a variety of techniques, which include but are not limited to in-row, overhead, and rear door heat exchanger (HX) cooling systems. One of the most common liquid cooling techniques will be examined in this study based on different conditions for high-power density racks (+50 kW). This paper investigates the cooling performance of a liquid-to-air in-row coolant distribution unit (CDU) in test racks containing seven thermal test vehicles (TTVs) under various conditions, focusing on cooling capacity and HX effectiveness under different supply air temperatures (SAT). This test rig has the necessary instruments to monitor and analyze the experiments on both the liquid coolant and the air sides. Moreover, another experiment is conducted to assess the performance of the CDU that runs under different control fan schemes, as well as how the change of the control type will affect the supply fluid temperature and the TTV case temperatures at 10%, 50%, and 100% of the total power. Finally, suggestions for the best control fan scheme to use for these systems and units are provided at the conclusion of the study.
Molecular mechanism of trehalose 6-phosphate inhibition of the plant metabolic sensor kinase SnRK1
Authors: Blanford Jantana , Zhai Zhiyang , Baer Marcel D. , Guo Gongrui , Liu Hui , Liu Qun , Raugei Simone , Shanklin John
Published: May 2024

SUCROSE-NON-FERMENTING1-RELATED PROTEIN KINASE1 (SnRK1), a central plant metabolic sensor kinase, phosphorylates its target proteins, triggering a global shift from anabolism to catabolism. Molecular modeling revealed that upon binding of KIN10 to GEMINIVIRUS REP-INTERACTING KINASE1 (GRIK1), KIN10’s activation T-loop reorients into GRIK1’s active site, enabling its phosphorylation and activation. Trehalose 6-phosphate (T6P) is a proxy for cellular sugar status and a potent inhibitor of SnRK1. T6P binds to KIN10, a SnRK1 catalytic subunit, weakening its affinity for GRIK1. Here, we investigate the molecular details of T6P inhibition of KIN10. Molecular dynamics simulations and in vitro phosphorylation assays identified and validated the T6P binding site on KIN10. Under high-sugar conditions, T6P binds to KIN10, blocking the reorientation of its activation loop and preventing its phosphorylation and activation by GRIK1. Under these conditions, SnRK1 maintains only basal activity levels, minimizing phosphorylation of its target proteins, thereby facilitating a general shift from catabolism to anabolism.
Monocytes in type 1 diabetes families exhibit high cytolytic activity and subset abundances that correlate with clinical progression
Authors: Pant Tarun , Lin Chien-Wei , Bedrat Amina , Jia Shuang , Roethle Mark F. , Truchan Nathan A. , Ciecko Ashley E. , Chen Yi-Guang , Hessner Martin J.
Published: May 2024

Monocytes are immune regulators implicated in the pathogenesis of type 1 diabetes (T1D), an autoimmune disease that targets insulin-producing pancreatic β cells. We determined that monocytes of recent onset (RO) T1D patients and their healthy siblings express proinflammatory/cytolytic transcriptomes and hypersecrete cytokines in response to lipopolysaccharide exposure compared to unrelated healthy controls (uHCs). Flow cytometry measured elevated circulating abundances of intermediate monocytes and >2-fold more CD14
+
CD16
+
HLADR
+
KLRD1
+
PRF1
+
NK-like monocytes among patients with ROT1D compared to uHC. The intermediate to nonclassical monocyte ratio among ROT1D patients correlated with the decline in functional β cell mass during the first 24 months after onset. Among sibling nonprogressors, temporal decreases were measured in the intermediate to nonclassical monocyte ratio and NK-like monocyte abundances; these changes coincided with increases in activated regulatory T cells. In contrast, these monocyte populations exhibited stability among T1D progressors. This study associates heightened monocyte proinflammatory/cytolytic activity with T1D susceptibility and progression and offers insight to the age-dependent decline in T1D susceptibility.
Nanocavity in hollow sandwiched catalysts as substrate regulator for boosting hydrodeoxygenation of biomass-derived carbonyl compounds
Authors: Zheng Fengbin , Cao Zhouwen , Lin Tian , Tu Bin , Shao Shengxian , Yang Caoyu , An Pengfei , Chen Wenxing , Fang Qiaojun , Wang Yinglong , Tang Zhiyong , Li Guodong
Published: May 2024

Hydrodeoxygenation of oxygen-rich molecules toward hydrocarbons is attractive yet challenging in the sustainable biomass upgrading. The typical supported metal catalysts often display unstable catalytic performances owing to the migration and aggregation of metal nanoparticles (NPs) into large sizes under harsh conditions. Here, we develop a crystal growth and post-synthetic etching method to construct hollow chromium terephthalate MIL-101 (named as HoMIL-101) with one layer of sandwiched Ru NPs as robust catalysts. Impressively, HoMIL-101@Ru@MIL-101 exhibits the excellent activity and stability for hydrodeoxygenation of biomass-derived levulinic acid to gamma-valerolactone under 50°C and 1-megapascal H
2
, and its activity is about six times of solid sandwich counterparts, outperforming the state-of-the-art heterogeneous catalysts. Control experiments and theoretical simulation clearly indicate that the enrichment of levulinic acid and H
2
by nanocavity as substrate regulator enables self-regulating the backwash of both substrates toward Ru NPs sandwiched in MIL-101 shells for promoting reaction with respect to solid counterparts, thus leading to the substantially enhanced performance.
Comparison of the performance of two targeted metagenomic virus capture probe-based methods using reference control materials and clinical samples
Authors: Mourik Kees , Sidorov Igor , Carbo Ellen C. , van der Meer David , Boot Arnoud , Kroes Aloysius C. M. , Claas Eric C. J. , Boers Stefan A. , de Vries Jutte J. C.
Published: May 2024

Viral enrichment by probe hybridization has been reported to significantly increase the sensitivity of viral metagenomics. This study compares the analytical performance of two targeted metagenomic virus capture probe-based methods: (i) SeqCap EZ HyperCap by Roche (ViroCap) and (ii) Twist Comprehensive Viral Research Panel workflow, for diagnostic use. Sensitivity, specificity, and limit of detection were analyzed using 25 synthetic viral sequences spiked in increasing proportions of human background DNA, eight clinical samples, and American Type Culture Collection (ATCC) Virome Virus Mix. Sensitivity and specificity were 95% and higher for both methods using the synthetic and reference controls as gold standard. Combining thresholds for viral sequence read counts and genome coverage [respectively 500 reads per million (RPM) and 10% coverage] resulted in optimal prediction of true positive results. Limits of detection were approximately 50–500 copies/mL for both methods as determined by ddPCR. Increasing proportions of spike-in cell-free human background sequences up to 99.999% (50 ng/mL) did not negatively affect viral detection, suggesting effective capture of viral sequences. These data show analytical performances in ranges applicable to clinical samples, for both probe hybridization metagenomic approaches. This study supports further steps toward more widespread use of viral metagenomics for pathogen detection, in clinical and surveillance settings using low biomass samples.

IMPORTANCE

Viral metagenomics has been gradually applied for broad-spectrum pathogen detection of infectious diseases, surveillance of emerging diseases, and pathogen discovery. Viral enrichment by probe hybridization methods has been reported to significantly increase the sensitivity of viral metagenomics. During the past years, a specific hybridization panel distributed by Roche has been adopted in a broad range of different clinical and zoonotic settings. Recently, Twist Bioscience has released a new hybridization panel targeting human and animal viruses. This is the first report comparing the performance of viral metagenomic hybridization panels.
Temperate phage-antibiotic synergy across antibiotic classes reveals new mechanism for preventing lysogeny
Authors: Al-Anany Amany M. , Fatima Rabia , Nair Gayatri , Mayol Jordan T. , Hynes Alexander P.
Published: May 2024

A recent demonstration of synergy between a temperate phage and the antibiotic ciprofloxacin suggested a scalable approach to exploiting temperate phages in therapy, termed temperate phage-antibiotic synergy, which specifically interacted with the lysis-lysogeny decision. To determine whether this would hold true across antibiotics, we challenged
Escherichia coli
with the phage HK97 and a set of 13 antibiotics spanning seven classes. As expected, given the conserved induction pathway, we observed synergy with classes of drugs known to induce an SOS response: a sulfa drug, other quinolones, and mitomycin C. While some β-lactams exhibited synergy, this appeared to be traditional phage-antibiotic synergy, with no effect on the lysis-lysogeny decision. Curiously, we observed a potent synergy with antibiotics not known to induce the SOS response: protein synthesis inhibitors gentamicin, kanamycin, tetracycline, and azithromycin. The synergy results in an eightfold reduction in the effective minimum inhibitory concentration of gentamicin, complete eradication of the bacteria, and, when administered at sub-optimal doses, drastically decreases the frequency of lysogens emerging from the combined challenge. However, lysogens exhibit no increased sensitivity to the antibiotic; synergy was maintained in the absence of RecA; and the antibiotic reduced the initial frequency of lysogeny rather than selecting against formed lysogens. Our results confirm that SOS-inducing antibiotics broadly result in temperate-phage-specific synergy, but that other antibiotics can interact with temperate phages specifically and result in synergy. This is the first report of a means of chemically blocking entry into lysogeny, providing a new means for manipulating the key lysis-lysogeny decision.

IMPORTANCE

The lysis-lysogeny decision is made by most bacterial viruses (bacteriophages, phages), determining whether to kill their host or go dormant within it. With over half of the bacteria containing phages waiting to wake, this is one of the most important behaviors in all of biology. These phages are also considered unusable for therapy because of this behavior. In this paper, we show that many antibiotics bias this behavior to “wake” the dormant phages, forcing them to kill their host, but some also prevent dormancy in the first place. These will be important tools to study this critical decision point and may enable the therapeutic use of these phages.
Post-market surveillance of six COVID-19 point-of-care tests using pre-Omicron and Omicron SARS-CoV-2 variants
Authors: Exner Hannah M. , Gregorchuk Branden S. J. , Castor AC-Green , Crisostomo Leandro , Kolsun Kurt , Giesbrecht Shayna , Dust Kerry , Alexander David C. , Bolaji Ayooluwa , Quill Zoe , Head Breanne M. , Meyers Adrienne F. A. , Sandstrom Paul , Becker Michael G.
Published: May 2024

Post-market surveillance of test performance is a critical function of public health agencies and clinical researchers that ensures tests maintaining diagnostic characteristics following their regulatory approval. Changes in product quality, manufacturing processes over time, or the evolution of new variants may impact product performance. During the COVID-19 pandemic, a plethora of point-of-care tests (POCTs) was released onto the Canadian market. This study evaluated the performance characteristics of several of the most widely distributed POCTs in Canada, including four rapid antigen tests (Abbott Panbio, BTNX Rapid Response, SD Biosensor, and Quidel QuickVue) and two molecular tests (Abbott ID NOW and Lucira Check IT). All tests were challenged with 149 SARS-CoV-2 clinical positives, including multiple variants up to and including Omicron XBB.1.5, as well as 29 clinical negatives. Results were stratified based on whether the isolate was Omicron or pre-Omicron as well as by reverse transcriptase quantitative PCR Ct value. The test performance of each POCT was consistent with the manufacturers' claims and showed no significant decline in clinical performance against any of the variants tested. These findings provide continued confidence in the results of these POCTs as they continue to be used to support decentralized COVID-19 testing. This work demonstrates the essential role of post-market surveillance in ensuring reliability in diagnostic tools.

IMPORTANCE

Post-market surveillance of diagnostic test performance is critical to ensure their reliability after regulatory approval. This is especially critical in the context of the COVID-19 pandemic as the use of point-of-care tests (POCTs) became widespread. Our study focused on four rapid antigen tests (Abbott Panbio, BTNX Rapid Response, SD Biosensor, and Quidel QuickVue) and two molecular tests (Abbott ID NOW and Lucira Check IT) that were widely distributed across Canada, assessing their performance using many SARS-CoV-2 variants, including up to Omicron subvariant XBB.1.5. Overall, we found no significant difference in performance against any variant, reinforcing confidence in their use. As concerns in test efficacy have been raised by news outlets, particularly regarding the BTNX Rapid Response, this work is even more timely and crucial. Our research offers insights into the performance of widely used COVID-19 POCTs but also highlights the necessity for post-market surveillance.
Multi-scale, open-system magmatic and sub-solidus processes contribute to the chemical and isotopic characteristics of the Jurassic Guadalupe Igneous Complex, Sierra Nevada, California, USA
Authors: Ratschbacher Barbara C. , Ardill Katie , Keller C. Brenhin , Schoene Blair , Paterson Scott R. , Putirka Keith D. , Lackey Jade Star , Paige Matthew L.
Published: May 2024

The chemical and isotopic characteristics of a solidified pluton represent the integration of magmatic and sub-solidus processes operating across a range of spatial and temporal scales during pluton construction, crystallization, and cooling. Disentangling these processes and understanding where chemical and isotopic signatures were acquired requires the combination of multiple tools tracing processes at different time and length scales. We combine whole-rock oxygen and Sr-Nd isotopes, zircon oxygen isotopes and trace elements, and mineral compositions with published high-precision U-Pb zircon geochronology to evaluate differentiation within the bimodal Guadalupe Igneous Complex, Sierra Nevada, California (USA). The complex was constructed in ~300 k.y. between 149 and 150 Ma. Felsic magmas crystallized as centimeter- to meter-sized segregations in gabbros in the lower part of the complex and as granites and granophyres structurally above the gabbros. A central mingling zone separates the mafic and felsic units. Pluton-wide δ18O(whole-rock), δ18O(zircon), and Sr-Nd isotopic ranges are too large to be explained by in situ, closed-system differentiation, instead requiring open-system behavior at all scales. Low δ18O(whole-rock) and δ18O(zircon) values indicate assimilation of hydrothermally altered marine host rocks during ascent and/or emplacement. In situ differentiation processes operated on a smaller scale (meters to tens of meters) for at least ~200 k.y. via (1) percolation and segregation of chemically and isotopically diverse silicic interstitial melt from a heterogeneous gabbro mush; (2) crystal accumulation; and (3) sub-solidus, high-temperature, hydrothermal alteration at the shallow roof of the complex to modify the chemical and isotopic characteristics. Whole-rock and mineral chemistry in combination with geochronology allows deciphering open-system differentiation processes at the outcrop to pluton scale from magmatic to sub-solidus temperatures over time scales of hundreds of thousands to millions of years.
A randomized phase II trial to examine modified vaccinia Ankara-5T4 vaccine in patients with relapsed asymptomatic ovarian cancer (TRIOC)
Authors: Michael Agnieszka , Wilson William , Sunshine Sunny , Annels Nicola , Harrop Richard , Blount Daniel , Pandha Hardev , Lord Rosemary , Ngai Yen , Nicum Shibani , Stylianou Laura , Gwyther Stephen , McNeish Iain A , Hackshaw Allan , Ledermann Jonathan
Published: May 2024

Background

Immunotherapy directed at 5T4 tumor antigen may delay the need for further chemotherapy. An attenuated modified vaccinia Ankara virus containing the gene encoding for 5T4 (MVA-5T4) was studied in asymptomatic relapsed ovarian cancer.

Objective

To assess the effectiveness and safety of MVA-5T4 as treatment for asymptomatic relapsed ovarian cancer.

Methods

TRIOC was a phase II randomized (1:1), placebo-controlled, double-blind multicenter study. The primary aim was to assess the effectiveness and safety of MVA-5T4 as a treatment for asymptomatic patients with relapsed ovarian cancer. Eligible patients had International Federation of Gynecology and Obstetrics (FIGO) stage IC1–III or IVA epithelial ovarian, fallopian tube, or primary peritoneal carcinoma, Eastern Cooperative Oncology Group (ECOG) 0–1, with relapse defined by a rise in CA-125 to twice the upper limit of normal or low-volume disease on CT scan. The primary endpoint was disease progression (including deaths from ovarian cancer) at 25 weeks. Following a brief suspension, the trial restarted as a single-arm study. The revised single-arm design required 45 evaluable patients treated with MVA-5T4 to detect a 25-week progression rate of 50%, assuming an expected 70% rate without MVA-5T4; 85% power with one-sided 5% significance.

Results

A total of 94 eligible patients were recruited, median age was 65 years (range 42–82), median follow-up 34 months (range 2–46). Overall, 59 patients received MVA-5T4 and 35 patients received placebo. The median number of MVA-5T4 injections received was 7 (range 0–9), compared with a median of 6 (range 1–12) for patients receiving placebo. Median progression-free survival was the same in both arms (3.0 months). The 25-week progression rate was similar in both arms: 80.0% for patients treated with MVA-5T4 and 85.7% for those receiving placebo (risk difference −5.7%, 95% CI −21.4% to 10.0%). Median time to clinical intervention was improved with MVA-5T4: 7.6 months (range 6.7–9.5) vs 5.6 (range 4.9–7.6),

Conclusion

MVA-5T4 vaccination in patients with asymptomatic relapse was well-tolerated but did not improve the progression rate at 25 weeks. The majority of patients who received MVA-5T4 had clinical intervention later than those assigned to placebo.

Trial registration number

NCT01556841
.
Data discrepancies: Italian ministry reports on abortion, contextualised
Authors: Pullan Danielle , Gannon Payton
Published: May 2024

The Italian Ministry of Health reports annually on activities related to abortion and fertility, providing quantitative data that looks ripe for analysis. Actors ranging from activists to medical providers to European courts have criticised the data as misleading, but the Ministry reports have not changed. In this piece, we bring together different perspectives on this data from inside and outside academia and offer guidance on how it should—and should not—be used in research.

In this article, we collect a wide variety of publications ranging from civil society groups’ reports to court decisions, academic articles and investigative reporting and harmonise the way they engage with the Italian Ministry of Health’s data regarding abortion and particularly conscientious objection.

Analyses rooted in the demographic and medical data about abortion seekers, the abortion rates over time, the different methods of abortion, etc are trustworthy and can be used to extrapolate levels of abortion access. This dataset on conscientious objectors systematically undercounts objectors, implying a false equivalence between people who do not object and people who actually work in an abortion service. We recommend that the Ministry report both the number of objectors and the number of medical doctors working in abortion services.

The Italian Ministry of Health produces some valuable data about abortion, but conscientious objection is the key feature of abortion access in Italy, and this key datapoint is flawed. The Ministry could improve clarity and increase citizens’ trust in government reports by adding data on the number of abortion providers.
Availability, cost and affordability of essential medicines for chronic respiratory diseases in low-income and middle-income countries: a cross-sectional study
Authors: Stolbrink Marie , Ozoh Obianuju B , Halpin David M G , Nightingale Rebecca , Meghji Jamilah , Plum Catherine , Allwood Brian William , Jayasooriya Shamanthi , Mortimer Kevin
Published: May 2024

Contemporary data on the availability, cost and affordability of essential medicines for chronic respiratory diseases (CRDs) across low-income and middle-income countries (LMICs) are missing, despite most people with CRDs living in LMICs. Cross-sectional data for seven CRD medicines in pharmacies, healthcare facilities and central medicine stores were collected from 60 LMICs in 2022–2023. Medicines for symptomatic relief were widely available and affordable, while preventative treatments varied widely in cost, were less available and largely unaffordable. There is an urgent need to address these issues if the Sustainable Development Goal 3 is to be achieved for people with asthma by 2030.
Safety and efficacy of hemp-derived products in animal feeds—a narrative review
Authors: Mohamed Neijat , House James D.
Published: May 2024

The current interest in hemp is not limited to the medicinal use for humans, it is also gaining attention as a valuable feed ingredient for animals. For instance, the processing of whole hemp seed (HS) for the extraction of the oil can result in various feed materials for animals, including HS hulls, dehulled HS, HS oil, and HS cake/meal. However, currently, HS-derived products are not approved as feed ingredients in Canada, in part, because the safety and efficacy of these derivatives, like other jurisdictions, require certification by regulatory bodies for their use in animal feeds. In this context, this document reviews previous studies testing the application of hemp-derived products in various animal feeds, including poultry, swine, ruminants, as well as in aquaculture production to support their safety and efficacy. Furthermore, the document attempts to review available data on the transfer of delta-9-tetrahydrocannabinol (THC; the psychoactive component) into animal products. Hence, the aim of this work is to support future policy directions and guidelines for the application of various hemp-derived products in animal feeds.
Climate, wildfire, and volcanic ash drivers of ecosystem change in high mountain forests, British Columbia, Canada
Authors: Hebda Richard J. , Brown Kendrick J.
Published: May 2024

Northwest North America has unique high elevation Picea–Abies forests and parkland classified in British Columbia as the Engelmann Spruce–Subalpine–fir (ESSF) Biogeoclimatic zone. These ecosystems occur on a topographically and climatically complex landscape, juxtaposed with diverse vegetation types including alpine tundra, inland rain forest, dry conifer forest, and grasslands. Spatio-temporal ecosystem disturbance is varied, driven by factors such as climate variation, wildfire, volcanic eruptions, and insect herbivory. A pollen and charcoal record derived from a lake sediment core from the ESSF reveals a unique late-glacial to modern vegetation history progressing from alpine steppe through dry open conifer forest to moist spruce–fir ecosystems, the latter arising only 4600 years ago, late by comparison to other ESSF sites in the region. Repeated disturbance in the mid Holocene by wildfire coupled with volcanic ash deposition and increased climatic variation resulted in recurring Pinus contorta-dominated seral forest stands before cooling and moistening in the late Holocene led to stable Picea–Abies forest. With rapid climate change, changing disturbance regimes, and timber harvest, the management of dry ESSF forests needs to consider that this forest-type could transform into parkland or open seral pine stands, with a high frequency disturbance regime.
Spin–orbit-coupled Bose gas with Rydberg interactions confined in a two-dimensional optical lattice
Authors: Wang Lin-Xue , Kong Fang , Yang Hong-Li , Zhai Hao-Han , Liu Hui , Yang Xue-Ying , Zhang Xiao-Fei
Published: May 2024

We consider the ground state of Rydberg-dressed Bose gas with spin–orbit coupling and confined in a two-dimensional optical lattice. The effects of system’s parameters, especially the nonlocal Rydberg interaction and spin–orbit coupling, on the ground-state structure of such a system are explored in full parameter space. It is found that in the absence of spin–orbit coupling, the ground-state structure of the system changes from the initial optical lattice structure to a two-dimensional periodic one with the cell size decreasing with the strength of Rydberg interaction. In the presence of spin–orbit coupling, both the phase and the internal structure of unit cell show strong dependence on the strength of spin–orbit coupling. Finally, the strong interacting gas is also considered.
Intraspecific variation in the functional response of an invasive crayfish under different temperatures
Authors: Chicatun Victoria , Sheppard Noemie L. M. , Ricciardi Anthony
Published: May 2024

Non-native species can react to changes to their thermal environment by altering their feeding behaviour, thereby potentially causing shifts in predator–prey dynamics and competitive dominance over native species. In this study, we measured intraspecific variation in the functional response (i.e., predation rate as a function of prey density) of the rusty crayfish Faxonius rusticus (Girard, 1852) at two temperatures (18 °C and 26 °C) in the laboratory. We compared six invasive populations spanning a 2° latitudinal gradient in eastern North America to test the prediction that under warmer conditions individuals from more southerly populations exhibit a higher functional response than those from northern populations. Temperature, latitude, and the interaction between these two variables had significant effects on attack rates and handling times of individual crayfish from the tested populations. Contrary to our prediction, the attack rates of individuals from northern populations were consistently higher than those from southern populations at both temperatures. We propose that these interpopulation differences in functional response could arise, at least in part, from countergradient selection. Our results suggest that climate warming promotes spatiotemporal variation in per capita effects across latitudinally distributed populations of aquatic invasive species.
Kobayashi complete domains in complex manifolds
Authors: Masanta Rumpa
Published: May 2024

In this paper, we give sufficient conditions for Cauchy-completeness of Kobayashi hyperbolic domains in complex manifolds. The first result gives a sufficient condition for completeness for relatively compact domains in several large classes of manifolds. This follows from our second result, which may be of independent interest, in a much more general setting. This extends a result of Gaussier to the setting of manifolds.
The secret structure of the gravitational vacuum
Authors: Mathur Samir D.
Published: May 2024

We argue that the vacuum of quantum gravity must contain a hierarchical structure of correlations spanning all length scales. These correlated domains (called “vecros”) correspond to virtual fluctuations of black hole microstates. Larger fluctuations are suppressed by their larger action, but this suppression is offset by a correspondingly larger phase space of possible configurations. We give an explicit lattice model of these vecro fluctuations, noting how their distribution changes as the gravitational pull of a star becomes stronger. At the threshold of formation of a closed trapped surface, these virtual fluctuations transition into on-shell black hole microstates (fuzzballs). Fuzzballs radiate from their surface like normal bodies, resolving the information paradox. We also argue that any model without vecro-type extended vacuum correlations cannot resolve the paradox.
Mathematical Solution for Vibrational Response of Shear and Normal Deformable Advanced Metal Foam CMBS Treated with Nanocomposite Actuators
Authors: Arshid Ehsan , Azimi Mohadese , Moradi Mahdi , El Ouni Mohamed Hechmi , Alashker Yasser
Published: May 2024

This research focuses on examining the vibrational properties of intelligent curved microbeams (CMBs) that incorporate metal foams and are enhanced with carbon nanotubes-reinforced piezoelectric (CNTRP) actuators. An advanced four-variable theory for shear and normal deformation is applied in the polar coordinate framework to investigate the microstructure, thereby negating the need for a shear correction factor. Additionally, the modified couple stress theory (MCST) is utilized to account for scale effects. The structural attributes exhibit thickness-dependent alterations following predefined functions. The governing equations of motion are deduced using Hamilton’s principle. In instances where the structure has simply supported ends, Fourier series functions are utilized to solve these equations. The outcomes are cross-validated in contradiction with previously documented works with more straightforward setups. The inquiry investigates the effects of critical parameters on the vibrational response of the structure. The results are corroborated in simpler scenarios using existing data in the literature to ensure accuracy.
Harvesting Vibration Energy of a Longitudinally Vibrating Rod within a Width Frequency Band by Designing Variable Stiffness Equipment
Authors: Nie Xiuyi , Li Di , Cui Haijian , Chen Mingfei
Published: May 2024

Structural vibrations are widespread in various structures and contain abundant vibration energy. While numerous studies have focused on harvesting vibration energy from beams, plates, and cylinders, few have addressed the longitudinal vibration energy harvesting from rods, thus presenting challenges in achieving broadband vibration energy harvesting from longitudinally vibrating rods. Considering the engineering context and existing limitations, this study investigates the broadband harvesting of longitudinal vibration energy from a rod system. The study introduces a longitudinal vibration energy trapping mechanism (LVETM), with variable stiffness equipment as its key component. It validates the theory for broadband harvesting of longitudinal vibration energy in the rod system using variable stiffness support. The stiffness coefficients of the LVETM can be effectively controlled by altering its state, thereby laying the foundation for the theory of broadband harvest of longitudinal vibration energy in rod systems. Additionally, the output voltage responses from the longitudinally vibrating rod system indicate a region for broadband vibration energy harvesting. Within this region, controlling the states of LVETM can enhance the output voltage responses of the longitudinally vibrating rod. Overall, this research presents an effective method for broadband harvesting of vibration energy from longitudinally vibrating rods.
Natural Vibration Characteristics of a Cantilever Beam Parametrically Excited by Pitch Motion
Authors: Li Liang , Zhu Weidong , Wang Long , Wang Zhan , Li Yinghui
Published: May 2024

Natural vibration characteristics of a cantilever beam that is parametrically excited by pitch motion are theoretically investigated in this work. A partial differential equation governing the parametrically excited bending vibration of the beam is established by employing the generalized Hamiltonian principle. Normal modal functions of the bending vibration are obtained based on the method of separation of variables. It reveals that the dynamic pitch motion cannot change the modal shapes of the bending vibration of a uniform beam. Principal vibrations of the beam are studied by taking into account two cases of [Formula: see text] and [Formula: see text], where [Formula: see text] and [Formula: see text] are the first and second principal bending stiffness, respectively. The bending stiffness is considered as the superposition of a constant stiffness with a small perturbation. With the aid of the Fourier series theory and the method of multiple scales, the principal vibrations of the parametrically excited system at non-resonant and resonant cases are analyzed by introducing a small natural parameter [Formula: see text], while natural vibration characteristics of the beam are obtained and the orthogonal properties of modal functions are illustrated. Theoretical methods provided in this work are verified by using the finite element method, assumed modes method and direct numerical integrations to the governing equation based on a rectangular beam model. It reveals that theoretical results coincide with numerical results very well. Finally, the influences of design parameters including the beam height, beam width, beam length, slender ratio, aspect ratio, pitch amplitude, pitch frequency and pitch phase on natural frequencies of a harmonic pitching beam are discussed. It shows that the width, height, length, slender ratio, aspect ratio and pitch amplitude have dramatic influences on the natural frequencies of the pitching beam, while the pitch frequency and pitch phase have little effect on natural frequencies.
Betti splittings and multigraded Betti numbers of cover ideals of bipartite graphs
Authors: Murai Satoshi , Shiina Mitsuki
Published: May 2024

In this paper, we study Betti splittings of cover ideals of bipartite graphs. We prove that if [Formula: see text] is the cover ideal of a bipartite graph then the [Formula: see text]-partition of [Formula: see text] is a Betti splitting for any [Formula: see text]. We also prove that multigraded Betti numbers of any squarefree monomial ideal can appear in a certain part of multigraded Betti numbers of the cover ideal of a bipartite graph.
Class-preserving automorphisms of descending HNN extensions of abelian groups
Authors: Zhou Wei , Kim Goansu
Published: May 2024

We consider descending HNN extensions [Formula: see text], where [Formula: see text] is abelian. We show that class-preserving automorphisms of descending HNN extensions are all inner if [Formula: see text] is abelian and [Formula: see text]. It follows that outer automorphism groups of such conjugacy separable descending HNN extensions are residually finite.
M-injective hulls of topological modules
Authors: Anwar Yunita Septriana , Wijayanti Indah Emilia , Surodjo Budi , Sari Dewi Kartika
Published: May 2024

Let [Formula: see text] be a topological ring and [Formula: see text] be a topological [Formula: see text]-module. An [Formula: see text]-module [Formula: see text] is called topological [Formula: see text]-injective if, for every continuous monomorphism [Formula: see text] with [Formula: see text] an open submodule of [Formula: see text], and for every continuous homomorphism [Formula: see text], there exists a continuous homomorphism [Formula: see text] that extends [Formula: see text]. A topological [Formula: see text]-injective hull of [Formula: see text] is a minimal topological [Formula: see text]-injective extension of [Formula: see text]. If [Formula: see text] is a topological module in the category [Formula: see text], then [Formula: see text] has injective hulls in the categories [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], which are not necessarily the same in general. A topological [Formula: see text]-injective hull of [Formula: see text] in [Formula: see text] is the trace of [Formula: see text] in [Formula: see text], where [Formula: see text] is a topological injective hull of [Formula: see text] in [Formula: see text]. If [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] are injective hulls of [Formula: see text] in [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively, then [Formula: see text] and [Formula: see text]. Furthermore, we prove that an infinite direct sum of topological [Formula: see text]-injective hulls is homeomorphic to a topological [Formula: see text]-injective hull of the direct sum of topological [Formula: see text]-modules in [Formula: see text] if the direct sum of topological [Formula: see text]-injective hulls is an open submodule in the direct product of topological [Formula: see text]-injective hulls.
*-Reverse derivations on alternative algebras
Authors: de Barros Dylene Agda Souza , Ferreira Bruno Leonardo Macedo , Guzzo Henrique
Published: May 2024

If [Formula: see text] is an alternative algebra containing a nontrivial symmetric idempotent, [Formula: see text] is a multiplicative ∗-reverse derivation and [Formula: see text] is a multiplicative Jordan ∗-reverse derivation, then under a mild condition on [Formula: see text] we prove that [Formula: see text] and [Formula: see text] are additives. Furthermore if [Formula: see text] is a Jordan ∗-reverse derivation, then under a mild condition on [Formula: see text] and [Formula: see text] we prove that [Formula: see text] is the form [Formula: see text], where [Formula: see text] is a ∗-reverse derivation of [Formula: see text] and [Formula: see text] is a singular Jordan ∗-reverse derivation of [Formula: see text]. Moreover, [Formula: see text] and [Formula: see text] are uniquely determined.
DESIGN OF SOFT EXOSKELETON STRUCTURE FOR HAND REHABILITATION ACTUATED BY SHAPE MEMORY ALLOY
Authors: ZUO KEXIN , WANG LICHAO , ZHENG SHUFANG , LI JIAN , WANG YANGWEI
Published: May 2024

Based on the previously designed hand rehabilitation exoskeleton structure, we propose a wearable soft hand rehabilitation device (HRD) actuated by shape memory alloy (SMA) wires. In order to accommodate the force and strain required for finger flexion and extension, the HRD with SMA wires-driven range extension mechanism has been redesigned to be 36.7% less long than the previous structure. In addition, we also designed the supporting structure for the SMA wires to stabilize the length of SMA wires and keep them tight to ensure the best actuation effect. Compared to previous work, the Coupled statics model is justified by analyzing the relationship between finger joint angles and fingertip forces during grasping. The experimental results show that the maximum sum of joint angle of the metacarpophalangeal (MCP) joint, proximal interphalangeal (PIP) joint, and distal interphalangeal (DIP) joint of the index finger is about 150°. The maximum fingertip forces of different fingers are different, ranging from 2 N to 7 N, depending on the geometrical size of each finger. The maximum operating temperature of the device is 31.7°C, which is within the safe range. This study demonstrates the feasibility of using the HRD to assist hand function rehabilitation.
MECHANICAL AND THERMAL PROPERTIES OF ROBOCASTED POLYCAPROLACTONE SCAFFOLDS
Authors: JAMIN ILANI MOHD , YAHYA MOHD YAZID , TAKAHASHI HIROSHI , ÖCHSNER ANDREAS , SULONG MOHD AYUB
Published: May 2024

Tissue scaffold engineering technology can eliminate the impediments in revision surgery. A decent understanding of the mechanical compression properties of biomaterials is required for producing increasingly suitable materials for their use as tissue engineering scaffolds. The biomaterial must not only possess structural integrity but also appropriate biodegradability with sufficient sustainability. This study presents a numerical simulation method and the material behavior results that quantify the mechanical compression properties of a polycaprolactone (PCL) cube-cell model using the finite element method (FEM). The main interest of this study is to observe and quantify the quasi-static compression behavior and the effective thermal conductivity of the PCL scaffolds. It is modeled as such as it undergoes degradation due to surface erosion by the body fluid onto the scaffold. The effective elastic modulus, 0.2% offset yield stress, plateau stress and effective thermal conductivity were evaluated numerically. Results show a phenomenologically decreasing trend of these general properties for PCL scaffolds computed by numerical methods. The volumetric decrease in PCL promotes weakening of the scaffold at its strut causing failure under compression. The effective thermal conductivity decreases as the volume decreases due to the lower PCL substance possessed in the unit cell, which is naturally a thermal insulator.
Identifying jumps in high-frequency time series by wavelets
Authors: Duran William R. , Morettin Pedro A.
Published: May 2024

We discuss a volatility functional model and show that jumps asymptotically impact the volatility estimate. This result is useful because our model shows that significant variations affect the estimation of the volatility and historically price series have structures with this type of behavior. We also discuss a method for detecting and locating jumps at different levels and show that the jumps tend to be detected by wavelet coefficients at lower resolution levels accurately. By checking the wavelet coefficients on the different levels, we can find dyadic intervals in some levels, whose corresponding absolute value of the wavelet coefficient exceeds a threshold, and is significantly higher than the others. We applied the procedure in a simulation study and to a series of Google stocks.
On generalization of Hermite–Hadamard–Mercer inequalities for interval-valued functions with generalized geometric–arithmetic convexity
Authors: Fahad Asfand , Qian Youhua , Ali Zammad , Younus Awais
Published: May 2024

In this paper, we introduce a new convexity notion for inter-valued functions, known as Geometrically–Arithmetically Cr-[Formula: see text]-convex functions (abbreviated as GA-Cr-[Formula: see text]-CFs) and explore its properties. The family of GA-Cr-[Formula: see text]-CFs simultaneously covers the family of GA-CFs, GA-[Formula: see text]-CFs and GA-Cr-CFs. On the other hand, we demonstrate its equivalence with convex functions (CFs), [Formula: see text]-CFs, Cr-CFs and Cr-[Formula: see text]-CFs via exponential function. We also investigate necessary and sufficient conditions for GA-Cr-[Formula: see text]-CFs via two corresponding real-valued GA-[Formula: see text]-CFs. Due to significance and applications of mathematical inequalities, we apply our findings and propose several inequalities such as Jensen–Mercer inequality (JMI), Hermite–Hadamard inequality (HHI) and weighted Hermite–Hadamard-type inequalities (wHHIs) for GA-Cr-[Formula: see text]-CFs. Through our results, we re-capture many known results and inequalities for subclasses of GA-Cr-[Formula: see text]-CFs studied in the recent literature.
Darboux and generalized Darboux transformations for the fractional integrable derivative nonlinear Schrödinger equation
Authors: Zhang Sheng , Zhang Yuying , Xu Bo , Li Xinyu
Published: May 2024

Analytical methods provide crucial mathematical insights into the stable solitary waves hidden in nonlinear phenomena. The nonlinear Schrödinger (NLS) equation is one of the most important typical integrable soliton models. From a mathematical perspective, the essence of the celebrated derivative NLS (DNLS) equation’s difference from the classical NLS equation lies in its cubic potential being differentiated once by the spatial variable and multiplied by the imaginary unit, which leads to the former having some characteristics that the latter cannot have. This paper extends the DNLS equation to the fractional integrable case with conformable derivative operators, and uses Darboux transformations (DTs) and generalized DT (GDT) to solve it exactly. Specifically, Lax pairs generating the fractional DNLS equation are first given. Based on the given Lax pairs, then the n-fold DTs and GDT for the fractional DNLS equation are derived. Some special exact solutions of the fractional DNLS equation are further obtained by employing the derived n-fold DTs and GDT. Finally, several novel space–time structures and dynamical evolutions of the obtained exact solutions are analyzed. This paper reveals through the DT and GDT methods that the double power-law fractional orders in the exact solutions of the fractional DNLS equation can be used to dominate the variable velocity propagation and anomalous diffusion in fractional dimensional media at different geometric scales.
Dynamical behaviors of a stochastic HIV/AIDS epidemic model with Ornstein–Uhlenbeck process
Authors: Shang Jia-Xin , Li Wen-He
Published: May 2024

AIDS is a chronic infectious disease that has been having a major impact on human health and social stability. In this paper, based on the deterministic SIATR model, a stochastic SIATR model is developed to account for the spread of AIDS by introducing the Ornstein–Uhlenbeck process. First, the existence and uniqueness of the global positive solution of the model are investigated. Second, a threshold [Formula: see text] is set: when [Formula: see text], the disease will become extinct; when [Formula: see text], the disease will persist. Then, it is shown that there exists a stationary distribution for the model when [Formula: see text]. On this basis, we derive the exact expression for the probability density function of the model in the neighborhood of the quasi-equilibrium state. Finally, the results of the previous proof are verified by several numerical simulations.