bluuebunny/crossref_metadata_2025 huggingface dataset:
Extremophile enzyme activity lab: using catalase from
Pyrobaculum calidifontis
to highlight temperature sensitivity and thermostable enzyme activity
Authors: Scott Joseph W. , Steel J. Jordan
Published: January 2024

There are places on earth that are considered to possess extreme physico-chemical characteristics as they relate to life. Surprisingly, there are microbes that have adapted various strategies that enable them to form robust communities in these environments. The microbes that live in these environments, called extremophiles, are described as being thermophilic, psychrophilic, halophilic, acidophilic, alkaliphilic, barophilic, and so on. Given that extremophiles were not discovered until relatively recently due to a view point that the environments in which they inhabited were not conducive to life, it is reasonable to conclude that the concept of extremophiles may be hard to grasp for students. Herein is described a laboratory exercise adapted from laboratory exercises that use mesophilic catalase enzymes to illustrate the influence of physico-chemical parameters on enzyme activity. Catalase is an enzyme that accelerates the degradation of hydrogen peroxide to water and oxygen gas. In addition to mesophilic catalases, the catalase from
Pyrobaculum calidifontis
, a hyperthermophile with an optimal growth temperature of 90°C, is used to highlight the adaptation of an enzyme to an extreme environment. A visual comparison of bubble production by the hyperthermophilic and mesophilic enzymes after heating at high temperatures dramatically illustrates differences in thermostability that will likely reinforce concepts that are given in a pre-laboratory lecture that discusses not only the extremophiles themselves but also their applications in biotechnology and possible role in the field of astrobiology.
Characterization of phage evolution and phage resistance in drug-resistant
Stenotrophomonas maltophilia
Authors: Han Pengjun , Lin Wei , Fan Huahao , Tong Yigang
Published: January 2024

Phage therapy is a promising approach to treat infections caused by drug-resistant
Stenotrophomonas maltophilia (S. maltophilia)
. However, the rapid development of phage resistance has hindered the therapeutic application of phages.
In vitro
evolutionary studies of bacteria–phage co-cultures can elucidate the mechanism of resistance development between phage and its host. In this study, we investigated the resistance trends between
S. maltophilia
and its phage and found that inhibition of phage adsorption is the primary strategy by which bacteria resist phage infection
in vitro
, while phages can re-infect bacterial cells by identifying other adsorption receptors. Although the final bacterial mutants were no longer infected by phages, they incurred a fitness cost that resulted in a significant reduction in virulence. In addition, the combination treatment with phage and aminoglycoside antibiotics could prevent the development of phage resistance in
S. maltophilia in vitro
. These findings contribute to increasing the understanding of the co-evolutionary relationships between phages and
S. maltophilia
.
Temperature influences commensal-pathogen dynamics in a nasal epithelial cell co-culture model
Authors: Huffines Joshua T. , Boone RaNashia L. , Kiedrowski Megan R.
Published: January 2024

Chronic rhinosinusitis (CRS) is an inflammatory disease of the paranasal sinuses, and microbial dysbiosis associated with CRS is thought to be a key driver of host inflammation that contributes to disease progression.
Staphylococcus aureus
is a common upper respiratory tract (URT) pathobiont associated with higher carriage rates in CRS populations, where
S. aureus
-secreted toxins can be identified in CRS tissues. Although many genera of bacteria colonize the URT, few account for the majority of sequencing reads. These include
S. aureus
and several species belonging to the genus
Corynebacterium
, including
Corynebacterium propinquum
and
Corynebacterium pseudodiphtheriticum
, which are observed at high relative abundance in the healthy URT. Studies have examined bacterial interactions between major microbionts of the URT and
S. aureus
, but few have done so in the context of a healthy versus diseased URT environment. Here, we examine the role of temperature in commensal, pathogen, and epithelial dynamics using an air-liquid interface cell culture model mimicking the nasal epithelial environment. Healthy URT temperatures change from the nares to the nasopharynx and are increased during disease. Temperatures representative of the healthy URT increase persistence and aggregate formation of commensal
C. propinquum and C. pseudodiphtheriticum
, reduce
S. aureus
growth, and lower epithelial cytotoxicity compared to higher temperatures correlating with the diseased CRS sinus. Dual-species colonization revealed species-specific interactions between
Corynebacterium
species and
S. aureus
dependent on temperature. Our findings suggest URT mucosal temperature plays a significant role in mediating polymicrobial and host-bacterial interactions that may exacerbate microbial dysbiosis in chronic URT diseases.

IMPORTANCE

Chronic rhinosinusitis is a complex inflammatory disease with a significant healthcare burden. Although presence of
S. aureus
and microbial dysbiosis are considered mediators of inflammation in CRS, no studies have examined the influence of temperature on
S. aureus
interactions with the nasal epithelium and the dominant genus of the healthy URT,
Corynebacterium
. Interactions between
Corynebacterium
species and
S. aureus
have been documented in several studies, but none to date have examined how environmental changes in the URT may alter their interactions with the epithelium or each other. This study utilizes a polarized epithelial cell culture model at air-liquid interface to study the colonization and spatial dynamics of
S. aureus
and clinical isolates of
Corynebacterium
from people with CRS to characterize the role temperature has in single- and dual-species dynamics on the nasal epithelium.
A shift between mineral and nonmineral sources of iron and sulfur causes proteome-wide changes in
Methanosarcina barkeri
Authors: Fausset Hunter , Spietz Rachel L. , Cox Savannah , Cooper Gwendolyn , Spurzem Scott , Tokmina-Lukaszewska Monika , DuBois Jennifer , Broderick Joan B. , Shepard Eric M. , Boyd Eric S. , Bothner Brian
Published: January 2024

Iron (Fe) and sulfur (S) are required elements for life, and changes in their availability can limit the ecological distribution and function of microorganisms. In anoxic environments, soluble Fe typically exists as ferrous iron [Fe(II)] and S as sulfide (HS
−
). These species exhibit a strong affinity that ultimately drives the formation of sedimentary pyrite (FeS
2
). Recently, paradigm-shifting studies indicate that Fe and S in FeS
2
can be made bioavailable by methanogens through a reductive dissolution process. However, the impact of the utilization of FeS
2
, as opposed to canonical Fe and S sources, on the phenotype of cells is not fully understood. Here, shotgun proteomics was utilized to measure changes in the phenotype of
Methanosarcina barkeri
MS grown with FeS
2
, Fe(II)/HS
−
, or Fe(II)/cysteine. Shotgun proteomics tracked 1,019 proteins overall, with 307 observed to change between growth conditions. Functional characterization and pathway analyses revealed these changes to be systemic and largely tangential to Fe/S metabolism. As a final step, the proteomics data were viewed with respect to previously collected transcriptomics data to deepen the analysis. Presented here is evidence that
M. barkeri
adopts distinct phenotypes to exploit specific sources of Fe and S in its environment. This is supported by observed protein abundance changes across broad categories of cellular biology. DNA adjacent metabolism, central carbon metabolism methanogenesis, metal trafficking, quorum sensing, and porphyrin biosynthesis pathways are all features in the phenotypic differentiation. Differences in trace metal availability attributed to complexation with HS
−
, either as a component of the growth medium [Fe(II)/HS
−
] or generated through reduction of FeS
2
, were likely a major factor underpinning these phenotypic differences.

IMPORTANCE

The methanogenic archaeon
Methanosarcina barkeri
holds great potential for industrial bio-mining and energy generation technologies. Much of the biochemistry of this microbe is poorly understood, and its characterization will provide a glimpse into biological processes that evolved close to life’s origin. The discovery of its ability to extract iron and sulfur from bulk, solid-phase minerals shifted a longstanding paradigm that these elements were inaccessible to biological systems. The full elucidation of this process has the potential to help scientists and engineers extract valuable metals from low-grade ore and mine waste generating energy in the form of methane while doing so.
A late Eocene lamprophyre-carbonatite association in the SE Tibetan Plateau: Rapid basalt-induced H2O-saturated partial melting of the upper crust
Authors: Yang Tiannan , Xin Di , Xue Chuandong , Dong Mengmeng , Jiang Lili
Published: January 2024

The processes by which lamprophyres and associated carbonatites are generated remain subject to debate. The Wase Basin on the SE Tibetan Plateau contains trachytes, rhyolites, and minor carbonatites that were emplaced at 37–36 Ma. Coeval lamprophyre dikes are widespread in the adjacent regions. Geochemically and petrographically, both the extrusive trachytes and dikes can be classified as lamprophyre. The numerous millimete r-sized SiO2-rich and calcite-rich ocelli that occur within the trachytes and dikes are solidified pseudomorphs of felsic and calcic melt drops, respectively. These ocelli combined with inherited granitic zircons suggest magma mixing between the calcic melt or felsic melt and basaltic melt. Petrographic evidence, mineral compositions, and zircon textures and U-Pb ages (827–682 Ma) suggest that the felsic melt and the calcic melt were generated by rapid H2O-saturated partial melting of Neoproterozoic granite and limestone, respectively, at >800 °C and <2 kbar, according to available experimental data. These melts were separated from each other and were stored at upper crustal depths, forming a zone of transient magma lenses or parcels. Melts mixed when an ascending basaltic magma intersected this zone. Reaction between the basaltic melt and the calcic melt occurred when they mixed, which formed clinopyroxene of predominantly diop side-hedenbergite solid solution. The observed heterogeneity of the upper crust combined with the variable degrees of magma mixing account for the great chemical diversity of the lamprophyres of SE Tibet. This model sheds new light on the petrogenesis of other lamprophyre-carbonatite associat ions elsewhere.
Chronostratigraphy of Miocene strata in the Berkeley Hills (California Coast Ranges, USA) and the arrival of the San Andreas transform boundary
Authors: Gerasimov Stacey H. , Hodgin Eben B. , Crowley James L. , Swanson-Hysell Nicholas L.
Published: January 2024

Miocene strata of the Claremont, Orinda, and Moraga formations of the Berkeley Hills (California Coast Ranges, USA) record sedimentation and volcanism during the passage of the Mendocino triple junction and early evolution of the San Andreas fault system. Detrital zircon laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) age spectra indicate a change in sedimentary provenance between the marine Claremont formation (Monterey Group) and the terrestrial Orinda and Moraga Formations associated with uplift of Franciscan Complex lithologies. A sandstone from the Claremont formation produced a detrital zircon chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) maximum depositional age of 13.298 ± 0.046 Ma, indicating younger Claremont deposition than previously interpreted. A trachydacite tuff clast within the uppermost Orinda Formation yielded a CA-ID-TIMS U-Pb zircon date of 10.094 ± 0.018 Ma, and a dacitic tuff within the Moraga Formation produced a CA-ID-TIMS U-Pb zircon date of 9.974 ± 0.014 Ma. These results indicate rapid progression from subsidence in which deep-water siliceous sediments of the Claremont formation were deposited to uplift that was followed by subsidence during deposition of terrestrial sediments of the Orinda Formation and subsequent eruption of the Moraga Formation volcanics. We associate the Orinda tuff clast and Moraga volcanics with slab-gap volcanism that followed the passage of the Mendocino triple junction. Given the necessary time lag between triple junction passage and the removal of the slab that led to this volcanism, subsidence associated with ca. 13 Ma Claremont sedimentation and subsequent Orinda to Moraga deposition can be attributed to basin formation along the newly arrived transform boundary.
Radiation-Geochemical Characteristics of Cryoconite Sediments on the Witte Glacier (Novaya Zemlya Archipelago)
Authors: Miroshnikov A. Yu. , Asadulin En. E. , Kudikov A. V. , Aliev R. A. , Fedulov V. Yu. , Khvostikov V. A. , Flint M. V.
Published: January 2024

The article presents the results of studying specific organomineral formations—cryoconite sediments—samples of which were taken on the surface of the Witte Glacier (Medvezhiy Bay, Novaya Zemlya) on cruise 76 of the R/V Akademik Mstislav Keldysh. The specific activities of 137Cs, 241Am, 207Bi, 210Pb, and 7Be were measured in 14 samples. Analysis of the materials suggests that cryoconite contains radioactive contamination deposited in the glacier in the period from September 1957 to December 1962 as a result of atmospheric nuclear explosions at the Sukhoy Nos test site, located 100 km from the glacier. Extremely high Bi, Ag, Sb, Mo, Pb, Sn contents and a strong correlation with anthropogenic radionuclides may indicate the technogenic emission of these elements during the destructive impact of nuclear explosions on bedrock, the metallogenic specialization of which corresponds to rich polymetallic mineralization.
Nitidine Chloride Inhibits Proliferation and Induces Mitochondrial-Mediated Apoptosis of Human Melanoma A375 and A2058 Cells In Vitro
Authors: Yexian Li  , Yao Yue , Zeng Linxi , Zhang Jinfang , Zhang Guoqiang
Published: January 2024

Melanoma is a malignant tumor transforming from normal melanocytes, with strong invasion and low survival rate. Nitidine chloride (NC) is a natural benzophenidine alkaloid extracted from the roots of traditional Chinese medicine zanthoxylum nitidum. In recent years, many studies have found that NC may have strong anti-tumor activity. However, the efficacy of NC against melanoma has rarely been reported, and the potential molecular mechanism remains unknown. Our study explored the effects of NC on the proliferation and apoptosis of human melanoma A375 and A2058 cells. CCK-8 was utilized to detect the effects of different concentrations of NC on the proliferation of A375 and A2058 cells. Within a certain concentration and time range, NC can inhibit the viability of A375 and A2058 cells significantly in a time-dose-dependent manner. In addition, NC-induced apoptosis was confirmed by DAPI staining and flow cytometry analysis of Annexin V-FITC/PI. Moreover, we observed that the ratio of Bax/Bcl-2 in the cytoplasm increases, activating Caspase-3/-9 and ultimately inducing apoptosis via the mitochondrial pathway. Our study indicated that NC has anti-tumor properties against human melanoma cells through inhibiting proliferation and inducing apoptosis. Therefore, the results provide new insights for future work on the utilization of NC in malignant melanoma treatment.
Dichotomic Role of Low-Concentration EGCG in the Oxaliplatin Sensitivity of Colorectal Cancer Cells
Authors: Wang Zhiyong , Wang Min , Huang Jiahao , Lin Mao , Wei Pei
Published: January 2024

Although epigallocatechin-3-gallate (EGCG) can potentiate chemotherapeutic drugs at high concentrations, its clinical translation is hampered by exceeding possible concentration thresholds. This study proposes a dichotomous use of low-concentration EGCG in chemotherapy. During the first cycle of combined treatment with oxaliplatin (OXA), low-concentration EGCG antagonized the cytotoxic effect of OXA on colorectal cancer (CRC) cells. However, when OXA was subsequently administered, the sensitivity of CRC cells markedly increased. Although low-concentration EGCG counteracted OXA, it reduced the OXA-induced secretion of vascular endothelial growth factor by tumor cells, thereby contributing to the increase in the sensitivity of tumor cells to the second round of OXA treatment. Therefore, low-concentration EGCG showed potential as a viable adjunct to modulate chemosensitivity in CRC.
Immunoliposomes As a Promising Antiviral Agent against SARS-CoV-2
Authors: Bobik T. V. , Simonova M. A. , Rushkevich N. U. , Kostin N. N. , Skryabin G. A. , Knorre V. D. , Schulga A. A. , Konovalova E. V. , Proshkina G. M. , Gabibov A. G. , Deev S. M.
Published: January 2024

According to the World Health Organization, as of January 3, 2020 to September 13, 2023, there were approximately 23 million confirmed cases of COVID-19 reported in the Russian Federation, about 400 thousand of which were fatal. Considering the high rate of mutation of the RNA-containing virus genome, which inevitably leads to the emergence of new infectious strains (Eris and Pyrola), the search for medicinal antiviral agents remains an urgent task. Moreover, taking into account the actively mutating receptor-binding domain, this task requires fundamentally new solutions. This study proposes a candidate immunoliposomal drug that targets the S protein of SARS-CoV-2 by the monoclonal neutralizing antibody P4A1 and ensures the penetration of a highly active ribonuclease into the virus-infected cell, which degrades, among cellular RNA, viral RNA too. We demonstrate a more than 40-fold increase in the neutralizing activity of the developed drug compared to the free monoclonal neutralizing antibody.
Neuronal and Muscle Differentiation of Mammalian Cells Is Accompanied by a Change in PHF10 Isoform Expression
Authors: Bayramova D. O. , Azieva A. M. , Feoktistov A. V. , Georgieva S. G. , Soshnikova N. V.
Published: January 2024

The PBAF chromatin remodeling complex of the SWI/SNF family plays a critical role in the regulation of gene expression during tissue differentiation and organism development. The subunits of the PBAF complex have domains responsible for binding to N-terminal histone sequences. It determines the specificity of binding of the complex to chromatin. PHF10, a specific subunit of the PBAF complex, contains a DPF domain, which is a unique chromatin interaction domain. A PHF10 isoform that lacks the DPF domain is also present in vertebrate cells. This work shows that during neuronal and muscle differentiation of human and mouse cells, the expression of PHF10 isoforms changes: the form that does not have DPF replaces the form in which it is present. Replacement of PHF10 isoforms in the PBAF complex may affect its selectivity in the regulation of genes in differentiating cells.
Effects of anisotropy on the electronic structure and nonlinear optical rectification in a quantum dot with hydrogen molecular ion
Authors: Sari H.
Published: January 2024

In this study, the effects of anisotropy and quantum dot size on energy levels and nonlinear optical rectification of a $$D_{2}^{ + }$$

D

2

+

molecular complex confined to a two-dimensional quantum dot are investigated. The energy eigenvalues and corresponding eigenfunctions of the resulting eigenvalue equation are obtained using the adiabatic approach and the two-dimensional diagonalization method. We conclude that the evolution of the energy spectrum depends predominantly on the anisotropy-induced change of geometric confinement size. In addition, it has been determined that the peak position of the nonlinear optical rectification shifts to lower or higher energies as the asymmetry of the system increases, depending on whether the QD is in the oblate or prolate case. This feature can be considered an advantage in tuning the nonlinear optical properties of systems based on two-dimensional semiconductor heterostructures.
Impact of population size on epidemic spreading in a bipartite metapopulation network with recurrent mobility
Authors: Wang Hao-Jie , Xu Yuan-Hao , Li Ming , Hu Mao-Bin
Published: January 2024

The mobility pattern of a population plays a key role in the spread of epidemics. Despite extensive work on epidemic spreading, little attention has been paid to the impact of subpopulation size. This paper investigates the spread of epidemics on a bipartite metapopulation network considering recurrent mobility patterns and different sizes of subpopulations. With the Markovian process approach, the epidemic threshold can be predicted as a function of subpopulation size and epidemic parameters. Simulation and theoretical results indicate that there exists a critical mobility intensity below which the epidemic will be eliminated, while limiting the size of the subpopulation can suppress the epidemic. Additionally, the epidemic threshold will approach zero when the size of the public area is large. The results can help the prevention of epidemic spreading under recurrent crowd mobility.
Modeling of mixed traffic flow and safety evaluation in the upstream area of the bus station
Authors: Li Chuan-Yao , Li Bing-Qian , Yin Jie , Chen Liang
Published: January 2024

The mixed traffic flow of various types of vehicles at bus station is severe, which has an impact on the overall safety of traffic. Especially upstream of bus station, since buses need to change lane in order to stop at the bus station, it interacts with social vehicles. Thus, in this paper, a two-lane CA model considering the mixed traffic flow composing of buses, cars and nonmotorized vehicles upstream of a bus station is proposed. Through several field surveys, the movement characteristics of the vehicles are obtained and the basic parameters are calibrated. For comparison, five cases about bus stops are studied. Several indexes (i.e. parallel time, blind area dwell time, time to collision, potential collision energy) are analyzed to assess the safety upstream of the bus station. Four safety indices are used to examine, based on simulation findings, the impact of bus station on vehicle safety and the significance of establishing exclusive nonmotorized vehicle lanes and exclusive bus lanes. Finally, several safety-related recommendations for drivers and management are provided. These findings offer a theoretical basis for driver management and optimal design of bus stations.
Quantifying the relationship between mobility patterns and socioeconomic status of dockless bike-sharing users
Authors: Yang Yu , Gao Tianli , Xu Zikun , Zhang Yongping , Liu Chenxin , Shang Fan , Li Ruiqi
Published: January 2024

Cycling is among the healthiest, greenest, and most affordable means of transportation for a better future city, but mobility patterns of cyclists with different income have rarely been studied due to the limitation of data availability. Newly emergent dockless bike-sharing platforms that record detailed trip information provide us a unique opportunity. Attributing to its better usage flexibility and accessibility, dockless bike-sharing is booming over the past few years worldwide and reviving the cycling fashion in cities. In this work, by exploiting massive platform-collected trip records in four diversified Chinese cities, we reveal that individual mobility patterns, including radius of gyration and average travel distance, are similar among the users with different income, indicating that human beings all follow similar physical rules. However, collective mobility patterns, in terms of average range and diversity of visitation, and commuting direction, exhibit different behaviors and spatial patterns across income categories. Hotspot locations that attract a high volume of cycling activities are quite different over groups, and locations with either a lower or higher income level have a relatively low user ratio. Cyclists from lower income groups are inclined to visit less flourishing locations across all four cities, and have a higher fraction to commute toward the city center in larger cities and away from the city center in smaller cities. Middle income groups of cyclists generally have a higher visitation diversity except in Shanghai. Our findings would be helpful on designing better promotion strategies for dockless bike-sharing platforms and toward the transition to a more inclusive and sustainable transportation.
Numerical investigations of the fractional order derivative-based accelerating universe in the modified gravity
Authors: Alderremy A. A. , Gómez-Aguilar J. F. , Sabir Zulqurnain , Raja Muhammad Asif Zahoor , Aly Shaban
Published: January 2024

In this work, a Liouville–Caputo fractional order (FO) derivative for the mathematical system based on the accelerating universe in the modified gravity (AUMG), i.e. FO-AUMG is proposed to get more accurate solutions. The nonlinear dynamics of the FO-AUMG is classified into five dynamics. The performances of the designed nonlinear FO-AUMG are numerically stimulated with the stochastic procedures of Levenberg–Marquardt backpropagated (LMB) scheme-based neural networks. The statics for FO-AUMS is used for the nonlinear FO-AUMG as 72%, 16% and 12% for training, authorization, and testing. Twenty neurons in hidden layers have been used to approximate the solution of the nonlinear FO-AUMS. The comparison of three different cases of the nonlinear FO-AUMS is performed with dataset generated by Adams method. To validate the uniformity, legitimacy, precision, and competence of LMB-based adaptive neural networks, the outcomes of the state transitions parameters, regression, correlation, error-histogram plots have been exploited.
Effects of polarizing film arrangement on the viewing angle of polymer-dispersed liquid crystal films
Authors: Wu Yung-Lung , Wu Chang-Mou
Published: January 2024

Polymer-dispersed liquid crystal (PDLC) film is an electrically controlled dimming film in which the orientation of the liquid crystal molecules can be changed by applying an electric field. When the liquid crystals are perpendicular to the PDLC film, the film is transparent. Birefringence occurs after light passes through the liquid crystal molecules, resulting in two beams of light with perpendicular vibration directions. Therefore, PDLC film appears hazy when viewed from the side. In this study, a polarizing film was introduced to reduce the side-view haze, and its influence on the haze at different angles and positions was investigated. Experiment results revealed that aligning the PDLC film along the polarizing film’s absorption axis reduced the haze at all angles. When the polarizing film was attached to each side of the PDLC film and the absorption axis angle of the films was 0∘, a wide-viewing-angle PDLC film was obtained; at a 45∘ tilt, the haze only increased by 0.33%, and at 60∘ it maintained a clear field of view. This may be because only light in the same direction as the absorption axis passed through the film, reducing the amount of light that did not match the polymer refractive index.
NaYF4:Yb3+/Ho3+ up-conversion luminescence and its low temperature sensing characteristics
Authors: Hou Jin , Wang Zhaojin , Xu Xinyi , Zhao Xin , Zhang Tian
Published: January 2024

Pure hexagonal [Formula: see text]-NaYF4 micron crystals were synthesized by the hydrothermal method with the up-conversion luminescence properties studied by doping Yb[Formula: see text]/Ho[Formula: see text]. The up-conversion fluorescence spectra and fluorescence lifetime of [Formula: see text]-NaYF4 micron crystals were determined by FLS-980 transient fluorescence spectrometer. By changing the doping concentration of Yb[Formula: see text]/Ho[Formula: see text], the optimal doping concentration was confirmed to be 20%Yb[Formula: see text]/2%Ho[Formula: see text]. The fluorescence spectrum was obtained by changing pump power, the relationship between power and intensity was analyzed, and the [Formula: see text]-NaYF4 micron crystal green and red emission up-conversion process was obtained into a two-photon process. The 5F[Formula: see text]I8 and 5S[Formula: see text]I8 of the sample were thermally coupled to obtain a large absolute sensitivity (Sa) of low temperature. The maximum absolute sensitivity within the range of 64–194[Formula: see text]K is 0.0097[Formula: see text]K[Formula: see text] at 144[Formula: see text]K, while maximum absolute sensitivity at 333[Formula: see text]K is 0.00335[Formula: see text]K[Formula: see text] in the range of 293–493[Formula: see text]K. The experimental results show that the sensing characteristics of [Formula: see text]-NaYF4:Yb[Formula: see text]/Ho[Formula: see text] at low temperature are better than those at high temperature, and it has the potential to be used in the field of temperature sensing.
MICROSTRUCTURE AND WEAR BEHAVIOR CHARACTERIZATION OF STIR-CAST ALUMINUM 6063 ALLOY AND ITS FOAM: A COMPARATIVE STUDY
Authors: NAWAZ ALI , RANI SUSHILA
Published: January 2024

In this research work, aluminum 6063 alloy foam was synthesized through stir casting using varying amounts of titanium hydride as a foaming agent. A comparative microstructural and wear behavior analysis of stir-cast aluminum 6063 alloy and its foam is presented. The oxide and aluminide phases present as intermetallic compounds in the stir-cast aluminum 6063 alloy foam ensure the stability of the synthesized foam. In order to optimize the effect of wear parameters on the tribological properties of stir-cast aluminum 6063 alloy foam, the L933 orthogonal array (OA) was designed and modeled statistically. The tribological properties of stir-cast aluminum 6063 alloy and its foam were evaluated by pin-on-disc tests. The optimal tribological properties of the synthesized foam are 0.29 coefficient of friction, 8.6 N frictional force, and 0.00025 mm3/N-m specific wear rate. The tribological properties of stir-cast aluminum 6063 alloy foam are superior to those of aluminum 6063 alloy and comparable to other aluminum foams described in the literature.
Inverse limits of automorphisms of truncated polynomials and applications related to Jacobian conjecture
Authors: Chang Hao , Shu Bin , Yao Yu-Feng
Published: January 2024

In this note, we investigate Jacobian conjecture through investigation of automorphisms of polynomial rings in characteristic [Formula: see text]. Making use of the technique of inverse limits, we show that under Jacobian condition for a given homomorphism [Formula: see text] of the polynomial ring [Formula: see text], if [Formula: see text] preserves the maximal ideals, then [Formula: see text] is an automorphism.
Nil clean graphs associated with commutative rings
Authors: Bozorgzadeh Moloukkhatoon , Moghimi Hosein Fazaeli , Samiei Mahdi
Published: January 2024

Let [Formula: see text] be a commutative ring with identity and [Formula: see text] be the set of all nilpotent elements of [Formula: see text]. The nil clean graph of [Formula: see text], denoted by [Formula: see text], is a graph whose vertices are all nonzero nil clean elements of [Formula: see text] and two distinct vertices [Formula: see text] and [Formula: see text] are adjacent if and only if [Formula: see text] or [Formula: see text]. In this paper, we focus on [Formula: see text], the subgraph of [Formula: see text] induced by the set [Formula: see text]. It is observed that [Formula: see text] has a crucial role in [Formula: see text]. We prove that [Formula: see text] is connected with [Formula: see text] and [Formula: see text]. We investigate also the interplay between the ring-theoretic properties of [Formula: see text] and the graph-theoretic properties of [Formula: see text]. Moreover, the clique number and the chromatic number of [Formula: see text] for some classes of rings are determined.
The Study of Core–Shell Cobalt Ferrite–Barium Titanate Magnetoelectric Nanoparticles in Targeting and Optimized Drug Delivery: An Overview
Authors: Hossain Shadeeb , Guo Ruyan , Bhalla Amar
Published: January 2024

This review provides a comprehensive understanding of magnetoelectric (ME) nanocomposite, cobalt ferrite–barium titanate (CFO–BTO) as a potential candidate for targeting specific cells. The synthesized core–shell material uses strain-mediated coupling between magnetostrictive and piezoelectric material. CFO–BTO has the competitive advantage of a high ME coefficient and is biocompatible. The shape and size play a pivotal role in passive drug delivery due to the enhanced permeability and retention effect at tumor sites. Surfactants can also enhance drug absorption and influence the interaction with nanoparticle composite. A comparison between external magnetic field–frequency parameters to navigate the ME nanoparticle and trigger release of the drug at site is also reviewed. Coating the nanoparticles with a layer of surfactant can reduce the threshold external magnetic field for navigation and triggering of drug particle release, making the prospect viable for clinical studies.
Quadrature formulas on combinatorial graphs
Authors: Pesenson Isaac Z. , Pesenson Meyer Z. , Führ Hartmut
Published: January 2024

The goal of the paper is to establish quadrature formulas on combinatorial graphs. Three types of quadrature formulas are developed. Quadrature formulas of the first type are obtained through interpolation by variational splines. This set of formulas is exact on spaces of variational splines on graphs. Since bandlimited functions can be obtained as limits of variational splines we obtain quadrature formulas which are approximately exact on spaces of bandlimited functions. Accuracy of this type of quadrature formulas is given in terms of geometry of the set of nodes of splines and in terms of smoothness of functions which is measured by means of the combinatorial Laplace operator. Quadrature formulas of the second type are obtained through point-wise sampling for bandlimited functions and based on existence of certain frames in appropriate subspaces of bandlimited functions. The third type quadrature formulas are based on the average sampling over subgraphs. Our quadrature formulas which are based on sampling are exact on a relevant subspaces of bandlimited functions. The results of the paper have potential applications to problems that arise in data mining.
An Adaptive PML Finite Volume Algorithm for the Scattering by Periodic Gratings
Authors: Wang Zhoufeng , Cheng Yao
Published: January 2024

In this paper, we studied the finite volume formulations for solving the diffraction grating problem that is truncated by the perfectly matched layer (PML) technique. Based on a reliable the a-posteriori error estimate, an adaptive PML finite volume method is discussed for the numerical approximation of the diffraction grating problem. The PML parameters are obtained numerically by sharp a-posteriori error estimates of the PML finite volume method such as the thickness of the layer and the medium property. It is worth mentioning in the a-posteriori error estimates that we derive the error representation formula and use a [Formula: see text]-orthogonality property of the residual similar to the Galerkin orthogonality used in the finite element method. Furthermore, the lower bound is established to demonstrate the efficiency of the a-posteriori error estimates. Numerical experiments are given to illustrate the accuracy and robustness of our adaptive algorithm.
Generalized B-curvature tensor within the framework of Lorentzian β-Kenmotsu manifold
Authors: Singh Gyanvendra Pratap , Prajapati Pawan , Mishra Anand Kumar , Rajan
Published: January 2024

The objective of this paper is to study some curvature properties of generalized [Formula: see text]-curvature tensor on Lorentzian [Formula: see text]-Kenmotsu manifold. Here first, we describe certain vanishing properties of generalized [Formula: see text]-curvature tensor on Lorentzian [Formula: see text]-Kenmotsu manifold and obtained several interesting results. Next, we formulate [Formula: see text] semi-symmetric condition on Lorentzian [Formula: see text]-Kenmotsu manifold. Again, we discussed the generalized [Formula: see text] pseudo-symmetric condition on Lorentzian [Formula: see text]-Kenmotsu manifold. We also characterized generalized [Formula: see text] [Formula: see text]-recurrent Lorentzian [Formula: see text]-Kenmotsu manifold. Further, we deal with Lorentzian [Formula: see text]-Kenmotsu manifold satisfying [Formula: see text] condition.
The Q-deformed SUC, BUC hierarchies and the multi-component generalizations
Authors: Wang Fei , Zhu Min , Yan Zhaowen
Published: January 2024

In this paper, we construct two kinds of [Formula: see text]-differential integrable hierarchies. The first one is the [Formula: see text]-universal character of B-type (BUC) and lattice [Formula: see text]-BUC hierarchies expressed by [Formula: see text]-shift operators. It is also shown that the lattice [Formula: see text]-BUC hierarchy reduces to the [Formula: see text]-BUC hierarchy with certain conditions. The other one is the [Formula: see text]-deformed generalized symplectic Schur functions and the [Formula: see text]-deformed generalized Q-functions defined by [Formula: see text]-derivative operators. By means of the [Formula: see text]-deformed vertex operators, the [Formula: see text]-deformed symplectic universal character (SUC) and BUC hierarchies have been presented. Moreover, it is proved that [Formula: see text]-deformed generalized symplectic Schur functions and generalized Q-functions are solutions of the [Formula: see text]-deformed SUC and BUC hierarchies, respectively. Meanwhile, by using multi-component tau functions, we establish the multi-component [Formula: see text]-deformed SUC and BUC hierarchies. In addition, based upon the discrete tau functions, the multi-component modified [Formula: see text]-deformed SUC and BUC hierarchies have been discussed.
Generalized stochastic Korteweg-de Vries equations, their Painlevé integrability, N-soliton and other solutions
Authors: Akpan Udoh , Akinyemi Lanre , Ntiamoah Daniel , Houwe Alphonse , Abbagari Souleymanou
Published: January 2024

In this study, we study two generalized stochastic Korteweg-de Vries (KdV) equations. The Painlevé property of these nonlinear models is tested using Kruksal’s method, which establishes the model’s integrability. As a result, using Hirota’s bilinear approach and symbolic computation, the N-soliton solutions are constructed. In addition, the extended hyperbolic function method (EHFM), the modified Kudryashov method (MKM), and the sub-equation method (SEM) are used to acquire the bright soliton, dark soliton, singular soliton, periodic, rational, and exponential solutions. To help understand the dynamic features of the derived soliton solutions, we present a number of 2D, 3D, and contour graphs using appropriate parametric values.
Bianchi type-VI perfect fluid cosmological model in f(Q,T) gravity
Authors: Narzary Metoka , Dewri Mukunda
Published: January 2024

A spatially homogeneous and anisotropic Bianchi type-VI cosmological model in the framework of [Formula: see text] gravity has been studied by considering three different functional forms of [Formula: see text] i.e. [Formula: see text], [Formula: see text] and [Formula: see text]. The field equation of [Formula: see text] gravity has been solved with the help of the Bianchi type-VI line element. The cosmological parameters of the models are evaluated, and the dynamical aspects of the model have been discussed. The result agrees with the observations of accelerated expansion of the universe.
Nonlinear Forced Vibration of Curved Beam with Nonlinear Viscoelastic Ends
Authors: Mohamed N. , Mohamed S. A. , Eltaher M. A.
Published: January 2024

This article develops a mathematical formulation to investigate the nonlinear forced vibration of curved viscoelastic beam with nonlinear viscoelastic boundary conditions around buckled position numerically, for the first time. The nonlinear integro-differential equation of buckling problem and the corresponding nonlinear nonhomogeneous boundary conditions are discretized by the differential integral quadrature method (DIQM) and after that, they are solved via Newton-iterative method to compute the nonlinear static deflection paths. By employing DIQM, the linear vibration problem is converted to a linear eigenvalue problem that is solved easily. The Galerkin technique is implemented to reduce the nonlinear partial integro-differential equation governing the nonlinear dynamic problem into Duffing-type equation. The Duffing equation is discretized via periodic spectral differentiation matrix operators. Finally, the pseudo-arc length continuation algorithm is applied to solve the nonlinear eigenvalue problem resulting from the discretized duffing equation. Validation of numerical techniques implemented in the solutions is proved with previous works. Parametric studies are conducted to deliberate the influences of the amplitude of initial curvature, axial load, linear and nonlinear support parameters on the static and dynamic behaviors of straight and curved beams. It should be noted that the proposed algorithm computes both stable and unstable solutions.
A Novel Weak-Form Space Quadrature Element Method and Application in Analysis of Non-Homogeneous Truss Structure
Authors: Wang Kai , Feng Chuang , Zhou Ding
Published: January 2024

This work proposes an improved weak-form quadrature element (IWQE) method for analyzing non-homogeneous space truss structures. The present method combines the high accuracy of the traditional WQE method with the universality of the standard finite element (FE) method. In the analysis, the structure is divided into a series of non-homogeneous elements with large sizes, and discrete function values are used to describe unknown mechanical properties in an element. Chebyshev–Lobatto differential quadrature and Gauss–Lobatto integral quadrature are used to deal with the energy variation of the element. Therefore, the endpoints of the element are included in the quadrature points, resulting in symmetric and positive definite stiffness matrix and diagonal mass matrix that represent internal point displacements by its endpoints in advance, significantly reducing order. All the elements can be easily and conveniently implemented as in FE. Both displacement and force boundary conditions are considered, leading to easier element assembly and smaller global matrices than traditional WQE while maintaining higher accuracy than FE. A non-homogeneous space truss composed of 40 bars is taken as an example to demonstrate the merits of the proposed method in accuracy, efficiency and robustness. The order of the global matrix equation is only 51 in present method.
Dynamic Modeling and Analysis of Soft Dielectric Elastomer Balloon Actuator with Polymer Chains Crosslinks, Entanglements and Finite Extensibility
Authors: Singh Akhil Pratap , Sharma Atul Kumar
Published: January 2024

Soft dielectric elastomers (SDEs) represent a category of intelligent electroactive materials utilized in electro-mechanical actuation technology. The dynamic performance of these materials during actuation is notably affected by intrinsic factors like crosslinks, entanglements and the limited extensibility of polymer chains. In this paper, we provide a theoretical framework for modeling the dynamic behavior of a balloon actuator made up of soft dielectric elastomer. To account for the inherent characteristics of polymer chain networks, we employ a physics-based nonaffine material model proposed by Davidson and Goulbourne. The governing equation for dynamic motion is established using Euler–Lagrange’s equation of motion for conservative systems. The reported dynamic modeling framework is then utilized to explore the transient response, stability, periodicity and resonance properties of a dielectric elastomer balloon (DEB) actuator for varying levels of polymer chain crosslinks, entanglements and finite extensibility parameters. To assess the periodicity and stability of the nonlinear vibrations exhibited by the DEB actuator, we present Poincaré maps and phase-plane plots. The results demonstrate that changes in the density of polymer chain entanglements lead to transitions between quasi-periodic and aperiodic vibrations. These findings represent an essential initial step toward the design and production of intelligent soft actuators with diverse applications in future technologies.
Persistent homotopy groups of metric spaces
Authors: Mémoli Facundo , Zhou Ling
Published: January 2024

In this paper, we study notions of persistent homotopy groups of compact metric spaces. We pay particular attention to the case of fundamental groups, for which we obtain a more precise description via a persistent version of the notion of discrete fundamental groups due to Berestovskii–Plaut and Barcelo et al. Under fairly mild assumptions on the spaces, we prove that the persistent fundamental group admits a tree structure which encodes more information than its persistent homology counterpart. We also consider the rationalization of the persistent homotopy groups and by invoking results of Adamaszek–Adams and Serre, we completely characterize them in the case of the circle. Finally, we establish that persistent homotopy groups enjoy stability in the Gromov–Hausdorff sense. We then discuss several implications of this result including that the critical spectrum of Plaut et al. is also stable under this notion of distance.
Modulation mechanism of electronic and optical properties of Cs2SnX6 (X = Cl, Br and I) under hydrostatic or uniaxial pressure
Authors: Peng Cheng , Wei Jianwei , Wu Junhua , Ma Zengwei , Qiao Chenkai , Zeng Hui
Published: January 2024

The air-stable, low-toxicity double perovskite structure [Formula: see text] (X = Cl, Br and I) has attracted great attention due to its excellent potential in optoelectronic and photovoltaic applications. We used density functional theory to theoretically study the pressure response mechanism of double perovskite [Formula: see text]. The results show that pressure can effectively regulate the electronic structure and optical absorption properties of [Formula: see text]. When subjected to hydrostatic pressure ranging from 0 to 50 GPa, the bandgaps of [Formula: see text], [Formula: see text] and [Formula: see text] all exhibit a phenomenon of first decreasing and then increasing during the change. [Formula: see text] exhibits semimetallic properties when the valence band and conduction band begin to overlap under hydrostatic pressure of 2 GPa or higher. In addition, with increasing pressure, the optical absorption peak of [Formula: see text] shows a significant blue shift, and the absorption coefficient in the visible and near-infrared regions gradually increases. When a uniaxial pressure is applied to [Formula: see text] crystal, it significantly reduces in one direction and expands in the other two perpendicular directions. The structure changes from cubic phase to tetragonal phase. The optical absorption coefficient in the direction of pressure first increases and the others decrease.
Distance matrices for conjugate skew gain graphs
Authors: Shahul Hameed K. , Ramakrishnan K. O. , Biju K.
Published: January 2024

A conjugate skew gain graph is a skew gain graph with the labels (also called, the conjugate skew gains) from the field of complex numbers on the oriented edges such that they get conjugated when we reverse the orientation. In this paper, we introduce distance matrices for conjugate skew gain graphs and characterize balanced conjugate skew gain graphs using these matrices. We provide explicit formulae for the distance spectra of certain conjugate skew gain graphs.