bluuebunny/crossref_metadata_2025 huggingface dataset:
Crosslinking degree variations enable programming and controlling soft fracture via sideways cracking
Authors: Moreno-Mateos Miguel Angel , Steinmann Paul
Published: December 2024

Large deformations of soft materials are customarily associated with strong constitutive and geometrical nonlinearities that originate new modes of fracture. Some isotropic materials can develop strong fracture anisotropy, which manifests as modifications of the crack path. Sideways cracking occurs when the crack deviates to propagate in the loading direction, rather than perpendicular to it. This fracture mode results from higher resistance to propagation perpendicular to the principal stretch direction. It has been argued that such fracture anisotropy is related to deformation-induced anisotropy resulting from the microstructural stretching of polymer chains and, in strain-crystallizing elastomers, strain-induced crystallization mechanisms. However, the precise variation of the fracture behavior with the degree of crosslinking remains to be understood. Leveraging experiments and computational simulations, here we show that the tendency of a crack to propagate sideways in the two component Elastosil P7670 increases with the degree of crosslinking. We explore the mixing ratio for the synthesis of the elastomer that establishes the transition from forward to sideways fracturing. To assist the investigations, we construct a novel phase-field model for fracture where the critical energy release rate is directly related to the crosslinking degree. Our results demonstrate that fracture anisotropy can be modulated during the synthesis of the polymer. Then, we propose a roadmap with composite soft structures with low and highly crosslinked phases that allow for control over fracture, arresting and/or directing the fracture. The smart combination of the phases enables soft structures with enhanced fracture tolerance and reduced stiffness. By extending our computational framework as a virtual testbed, we capture the fracture performance of the composite samples and enable predictions based on more intricate composite unit cells. Overall, our work offers promising avenues for enhancing the fracture toughness of soft polymers.
Shear capacity of corrugated web steel beams strengthened with CFRP strips
Authors: EL Aghoury Mohamed A. , Dyab Alshaymaa K. , Ibrahim Sherif M. , Saddek Amr B.
Published: December 2024

In recent years, there has been significant advancement in strengthening techniques for steel structures using carbon-fiber reinforced polymer (CFRP). While numerous studies have focused on CFRP strengthening of steel beams with flat webs, similar investigations on corrugated web steel beams (CWSBs) remain limited despite their increasing application in various steel structures. This study presents numerical and analytical investigations aimed at evaluating the effectiveness of CFRP strengthening for CWSBs and developing a design procedure to predict the shear buckling capacity of strengthened CWSBs. The research employs a finite element (FE) model developed using ANSYS software, validated against previous experimental work by the same authors, which accurately reflects the overall behavior of CWSBs. A parametric study is conducted on 105 CWSBs using the validated FE model to assess the impact of various geometrical parameters, including beam web slenderness ratio, length and thickness of CFRP strips, and different CFRP strip schemes. Results demonstrate that CFRP strengthening can enhance the shear capacity of CWSBs by up to 74.50%. The study identifies the arrangement of CFRP strips on both sides of the web as the most effective parameter for controlling the efficiency of the CFRP strengthening technique. Conversely, changes in CFRP strips up to 70% of web height have minimal effect. A proposed design procedure for predicting the design shear buckling strength of CFRP-strengthened CWSBs shows good consistency with FE model results.
Genetic, phytochemical and morphological identification and genetic diversity of selected Moringa species
Authors: Hamada Fatma A. , Sabah Saleh S. , Mahdy Ehab M.B. , El-Raouf Hany S. Abd , El-Taher Ahmed M. , El-leel Omneya F.A. , Althobaiti Ashwaq T. , Ghareeb Mosad A. , Randhir Reena , Randhir Timothy O.
Published: December 2024

Moringa is the sole genus in the family Moringaceae used for medicinal and nutrient purposes. Morphological features, phytochemical attributes, and molecular characterization were used for the genetic association and classification among Moringa oleifera, M. peregrina, and M. stenopetala. Moringa peregrina recorded a similarity of 84% lonely and placed M. stenopetala with M. oleifera into a cluster score with a similarity of 95.3%. M. peregrina is characterized by phenolic content (243 mg/100 g), flavonoids (7 mg/100 g), and antioxidant activity (1226.85 mg/100 g). GC-MS analysis revealed that M. oleifera contained twenty compounds with 2-decenal (E) (39.14%), 2-undecenal (15.51%), nonanal (3.60%), and 2-octenal, (E) (2.48%), while M. peregrina identified eighteen compounds with 2-decenal (Z) (25.42%), 2-docecen-1-al (9.35%), and 13-Docosenoic acid, methyl ester, (Z) (4.16%). M. stenopetala identified fifteen compounds containing 2-decenal (E) (26.67%), 2-undecenal (24.10%), and nonanal (4.40%). A broad sense of similarity has been scored between M. oleifera and M. stenopetala by the phytochemical compositions, especially the similarity in the main compounds such as 2-decenal (E), 2-undecenal, and nonanal. It can be concluded that efforts need to be expanded to pay attention to study Moringa taxa, due to the rarity of Moringa peregrina, and the focus should be on sustainable utilization and conservation. The potential of these taxa would greatly benefit indigenous species in terms of their maintenance, and there is a need for more comprehensive bio-prospecting studies. Therefore, this study evaluates the variability among Moringa and highlights the significance of leaf and seed ultrastructure to provide more information and evaluate potential approaches.
Quantitative and qualitative analysis of bioaerosols emissions from the domestic eastern wastewater treatment plant, Alexandria, Egypt
Authors: El-Bestawy Ebtesam , Ibrahim Mohammed Mahmoud , Shalaby El sayed Ahmed
Published: December 2024

Bioaerosol studies showed that wastewater treatment plants (WWTPs) are a significant source of bioaerosol emissions. In this study, 170 samples of total bacteria, total coliform, and total fungi were collected from 10 sites within a domestic WWTP, Alexandria, Egypt, using the sedimentation technique. According to the Index of Microbial Air Contamination (IMA) classes, the total bacteria range was 108–5120 CFU/dm2/hour, and all samples were classified as “very poor” except one sample of an office, which was classified as “poor.” The total coliform range was 0–565 CFU/dm2/hour, and 6 samples were classified as “very poor,” while one sample was classified as “poor.” The total fungi range was 0–209 CFU/dm2/hour, and 9 samples were classified as “very poor,” while 4 samples were classified as “poor.” After the conversion to CFU/m3, the counts of total bacteria, total coliforms, and total fungi were 897 − 42.7 × 103, 0–4.71 × 103, and 0–2.69 × 103 CFU/m3, respectively. Several identified bioaerosols have been reported before as a cause of human infections. They included Lysinibacillus fusiformis, Bacillus cereus, Alcaligenes faecalis, Klebsiella sp., Escherichia coli, Aspergillus spp., Penicillium spp., Rhizopus sp., Candida sp., and Rhodotorula sp. These results indicated an increased health risk to WWTP staff, which needs more attention and more efficient control measures.
Antibacterial, antioxidant, cytotoxicity, and phytochemical screening of Moringa oleifera leaves
Authors: El-Sherbiny Gamal M. , Alluqmani Amira J. , Elsehemy Islam A. , Kalaba Mohamed H.
Published: December 2024

Bacterial resistance to antibiotics remains a significant clinical challenge, contributing to persistently high rates of morbidity and mortality. Achieving treatment success is increasingly difficult, necessitating the evaluation of new antibiotics and complementary approaches, including source control and alternative therapies. This study aimed to investigate the antibacterial, antioxidant, cytotoxic, and phytochemical properties of Moringa oleifera leaf extract using high-performance liquid chromatography (HPLC), and to evaluate the pharmacokinetic properties of its major compound. The extract demonstrated strong antibacterial activity against standard strains and foodborne bacterial species. It also showed significant antioxidant potential, supported by the presence of high concentrations of phenolic and flavonoid compounds. HPLC analysis identified multiple bioactive compounds, with quercetin as the predominant component. The cytotoxicity study confirmed the safety of the extract at low and moderate concentrations, and ADMET analysis indicated favorable pharmacokinetic characteristics of quercetin. In conclusion, Moringa oleifera exhibits promising potential for medical and food industry applications due to its significant antibacterial and antioxidant activities, combined with a strong safety profile and rich phytochemical content.
Synthesis of silylbut-1-en-3-ynes and buta-1,3-dienes as building blocks via hydrosilylation of 1,4-bis(trimethylsilyl)buta-1,3-diyne
Authors: Stefanowska-Kątna Kinga , Walkowiak Jędrzej , Franczyk Adrian
Published: December 2024

The selective and efficient synthesis of (E)-1,2,4-trisilylbut-1-en-3-ynes obtained via Pt-catalyzed hydrosilylation of 1,4-bis(trimethylsilyl)buta-1,3-diyne is described. Optimized reaction conditions (Pt(PPh3)4) or Pt2(dvs)3, 100 °C, toluene, 18 h) yielded compounds with high isolation yields (76–95%). The modification of (E)-1,2,4-trisilylbut-1-en-3-ynes was further tested in protodesilylation, halodesilylation, hydrosilylation, and Pd-based cross-coupling reactions, resulting in a broad spectrum of new products. These compounds represent new families of buta-1,3-dienes, (E,E)-2,3-bissilylbuta-1,3-dienes, (E,E)-1,2,3-trisilylbuta-1,3-dienes, and (E,E)-1,2,3-trisilylbuta-1,3-dienes, which are ideally suited to silicon-based transformations and are perfect models for the investigation of the reactivity of one silyl group in the presence of another.
Differential characteristics of vaginal versus endometrial microbiota in IVF patients
Authors: Polifke Alina , von Schwedler Annika , Gulba Rebecca , Bensmann Ralf , Dilthey Alexander , Nassar Najib N. R. , Finzer Patrick
Published: December 2024

Abnormal female reproductive tract microbiota are associated with gynecological disorders such as endometriosis or chronic endometritis and may affect reproductive outcomes. However, the differential diagnostic utility of the vaginal or the endometrial microbiome and the impact of important technical covariates such as the choice of hypervariable regions for 16 S rRNA sequencing remain to be characterized. The aim of this retrospective study was to compare vaginal and endometrial microbiomes in IVF patients diagnosed with implantation failure (IF) and/or recurrent pregnancy loss (RPL) and to investigate the overlap between established vaginal and endometrial microbiome classification schemes. An additional aim was to characterize to which extent the choice of V1-V2 or V2-V3 16 S rRNA sequencing schemes influences the characterization of genital microbiomes. We compared microbiome composition based on V1-V2 rRNA sequencing between matched vaginal smear and endometrial pipelle-obtained biopsy samples (n = 71); in a sub-group (n = 61), we carried out a comparison between V1-V2 and V2-V3 rRNA sequencing. Vaginal and endometrial microbiomes were found to be Lactobacillus-dominated in the majority of patients, with the most abundant Lactobacillus species typically shared between sample types of same patient. Endometrial microbiomes were found to be more diverse than vaginal microbiomes (average Shannon entropy = 1.89 v/s 0.75, p = 10−5) and bacterial species such as Corynebacterium sp., Staphylococcus sp., Prevotella sp. and Propionibacterium sp. were found to be enriched in the endometrial samples. The use of two widely used clinical classification schemes to detect microbiome dysbiosis in the reproductive tract often led to inconsistent results vaginal community state type (CST) IV, which is associated with bacterial vaginosis, was detected in 9.8% of patients; however, 31,0% of study participants had a non-Lactobacillus-dominated (NLD) endometrial microbiome associated with unfavorable reproductive outcomes. Results based on V2-V3 rRNA sequencing were generally consistent with V1-V2-based; differences were observed for a small number of species, e.g. Bifidobacterium sp., Propionibacterium sp. and Staphylococcus sp. and with respect to slightly increased detection rates of CST IV and NLD. Our study showed that endometrial microbiomes differ substantially from their vaginal counterparts, the application of a trans-cervical sampling method notwithstanding. Characterization of endometrial microbiomes may contribute to the improved detection of women with an unfavorable reproductive outcome prognosis in IVF patients..
A framework to automatically detect near-falls using a wearable inertial measurement cluster
Authors: Gießler Maximilian , Werth Julian , Waltersberger Bernd , Karamanidis Kiros
Published: December 2024

Accurate and automatic assessments of body segment kinematics via wearable sensors are essential to provide new insights into the complex interactions between active lifestyle and fall risk in various populations. To remotely assess near-falls due to balance disturbances in daily life, current approaches primarily rely on biased questionnaires, while contemporary data-driven research focuses on preliminary fall-related scenarios. Here, we worked on an automated framework based on accurate trunk kinematics, enabling the detection of near-fall scenarios during locomotion. Using a wearable inertial measurement cluster in conjunction with evaluation algorithms focusing on trunk angular acceleration, the proposed sensor-framework approach revealed accurate distinguishment of balance disturbances related to trips and slips, thereby minimising false detections during activities of daily living. An important factor contributing to the framework’s high sensitivity and specificity for automatic detection of near-falls was the consideration of the individual’s gait characteristics. Therefore, the sensor-framework presents an opportunity to substantially impact remote fall risk assessment in healthy and pathological conditions outside the laboratory.
Mitigating polysulfide crossover in lithium–sulfur batteries with polymer-coated separators
Authors: Nuwayhid R. Blake , Yeom Junghoon , Ford Hunter O. , Neale Zachary G. , Swift Michael W. , Bernstein Noam , Carter Rachel E. , Long Jeffrey W.
Published: December 2024

Initiated chemical vapor deposition (iCVD) coating of commercial battery separators enhance Li–S cell performance through mitigation of polysulfide crossover and stabilization of the Li anode/electrolyte interface.
Environmental and biomedical applications of 2D transition metal borides (MBenes): recent advancements
Authors: Iravani Siavash , Zarepour Atefeh , Khosravi Arezoo , Zarrabi Ali
Published: December 2024

This review aims to systematically investigate the environmental and biomedical applications of MBenes and their composites.
Matchbox Janus membrane fog collector with highly efficient directional transport
Authors: Hu Feifeng , Zhang Huayang , Tian Guangyi , Xie Shangzhen , Guo Zhiguang
Published: December 2024

In this paper, a Matchbox Janus membrane fog collector (MJMFC) prepared by chemical etching and thiol modification is described. It offers directional transport and rapid drainage, enhancing continues and efficient fog collection.
Layer-number-dependent photoswitchability in 2D MoS2-diarylethene hybrids
Authors: Park Sewon , Ji Jaehoon , Pillai Srajan , Fischer Henry , Rouillon Jean , Benitez-Martin Carlos , Andréasson Joakim , You Jeong Ho , Choi Jong Hyun
Published: December 2024

Optoelectronic properties of atomically-thin MoS2 flakes are modulated using photochromic diarylethene molecules. The layer-number-dependent charge transfer behaviors at the hybrid heterointerface are elucidated.
Wavelength-selective duotone single-component photochromic gallophosphate-oxalate with multidirectional UVB/UVC/NIR photoswitch electron transfer
Authors: Yi Zhihui , Wang Tieqiang , Li Xu , Wu Junbiao , Wang Zhuopeng , Liang Zhiqiang , Li Jiyang
Published: December 2024

A wavelength-selective duotone photochromic complex can visually distinguish UVB and UVC to colorimetrically detect indoor UVC and outdoor UVB, and exhibits modulated NIR photothermal conversion and high-speed photoswitching decoloration behavior.
Bismuth-based nanoparticles and nanocomposites: synthesis and applications
Authors: Kumar Sujit , Premkumar M. , Giri Jayant , Hasnain S. M. Mozammil , Zairov Rustem , Wu Jundao , Huang Zeai
Published: December 2024

In the vast landscape of materials science, bismuth emerges as a compelling element with unique properties and diverse applications.
Pyrazine derivative synthesis in a continuous-flow system: a green synthesis of pyrazinamide from pyrazine esters and amines catalyzed by Lipozyme® TL IM from Thermomyces lanuginosus
Authors: Zhang Ao-Ying , Huang Zong-Hao , Du Li-Hua , Lin Hang , Xie Han-Jia , Yan Bing-Lin , Xue Miao Miao , Wang Lin , Shao Wen-Xuan , Fu Guo-Neng , Luo Xi-Ping
Published: December 2024

The continuous flow synthesis of a series of pyrazinamide derivatives catalyzed by Lipozyme® TL IM was successfully achieved with good scalability. A continuous production of pyrazinamide derivatives was first performed coupled with enzymes.
Experimental verification of halomethyl carbinol synthesis from carbonyl compounds using a TiCl4–Mg bimetallic complex promoter
Authors: Michalak Olga , Żurawicka Sylwia , Kubiszewski Marek , Krzeczyński Piotr , Leś Andrzej , Filipek Sławomir , Cybulski Marcin
Published: December 2024

A mechanism for the formation of vicinal 1,2-diols in the presence of a bimetallic TiCl4–Mg promoter is proposed, supported by the analysis of experimental data (twelve examples) and theoretical DFT calculations (DFT/B3LYP).
Structure–reactivity relationships in CO2 hydrogenation to C2+ chemicals on Fe-based catalysts
Authors: Zhu Jie , Shaikhutdinov Shamil , Cuenya Beatriz Roldan
Published: December 2024

This review critically discusses recent in situ and operando studies on Fe-based catalysts in CO2 hydrogenation, in particular focusing on the effect of composition, promoters, support and particle size.
Folded–twisted mechanisms control dynamic redox properties, photophysics and electron transfer of anthanthrene-quinodimethanes
Authors: Cárdenas Valdivia Abel , Lirette Frédéric , Marín-Beloqui José M. , Carreras Abel , Casanova David , Boismenu-Lavoie Joël , Morin Jean-François , Casado Juan
Published: December 2024

The synthesis, electrochemical, spectroelectrochemical, photophysical and light induced electron transfer reactions in two new anthanthrene quinodimethanes have been studied and analyzed in the context of dynamic electrochemistry.
Bay-substituted perylene diimide-based donor–acceptor type copolymers: design, synthesis, optical and energy storage behaviours
Authors: Das Lalmohan , Das Puspendu , Ahamed Sk Mustak , Datta Ayan , Pal Arun K. , Datta Ayan , Malik Sudip
Published: December 2024

Four bay-substituted perylene diimide (PDI) copolymers have been designed and synthesized successfully to demonstrate the effect of bay-substituent on the photo-physical and capacitive properties.
A distinctive edge-graphited hard carbon for advanced sodium-ion batteries
Authors: Huang Jiuxiang , Zhang Qingwei , Yuan Mengwei , Chen Chaosheng , Bi Changwang , Lin Jianbo , Deng Hao , Du Haoshen , Liu Xiao , Chen Yanting , Gong Haiguang , Ni Qiao
Published: December 2024

A novel type of edge-graphitized hard carbon material was reported, which significantly reduced the sodium ion diffusion energy barrier, decreased the irreversible capacity loss and contributed to high ion diffusion kinetics.
Emerging bioengineering breakthroughs in precision diagnosis and therapy for endometriosis and adenomyosis
Authors: Peng Yujie , Zhang Meng , Yan Jingjing , Wang Rong , Xin Yu , Zheng Xiaoling , Zhu Libo , Fei Weidong , Zhao Mengdan
Published: December 2024

This review highlights the potential of bioengineering breakthroughs to transform the diagnosis and management of endometriosis and adenomyosis, emphasizing their role in advancing precision medicine and improving women's health.
Nanoporous and morphology-transforming g-CNNPs for trace-level detection of mefenamic acid in urine samples and in vitro protein denaturation inhibition
Authors: Gangadharan Anusree S. , Thangadurai Daniel T. , Manjubaashini Nandhakumar , Nataraj Devaraj
Published: December 2024

Nanoporous and morphology transforming g-CNNPs (size ca. 3.0 nm) are utilized for ultra-low concentration detection of MEF in urine samples at pH 7.0 and protein denaturation inhibition.
Prevalence of Parent-Reported Problematic Eating Behaviors and Skills at 8–24 Months of Age in Infants Born at Less Than 34 Weeks Gestation
Authors: Pados Britt F. , Briceno Grace , Feaster Victoria , Chiu Michelle
Published: December 2024

Purpose:

The purpose of this study was to describe the evolution and prevalence of parent-reported problematic feeding behaviors and eating skills in infants born prior to 34 weeks at the time of eating solid foods between 8 and 24 months of age, and to explore the associations between problematic feeding and the impact on the parent and family.

Method:

Parents of eligible children (
N
= 35) completed an online survey when their child was 8, 10, 12, 18, and 24 months corrected age. The survey included the Pediatric Eating Assessment Tool (PediEAT), Child Oral and Motor Proficiency Scale (ChOMPS), and the Feeding Impact Scales–Family and Parent.

Results:

The prevalence of problematic feeding behaviors, as measured by the PediEAT, decreased from 63% at 8 months to 29% at 24 months. The prevalence of problematic eating skills, as measured by the ChOMPS, ranged from 30% to 56% between 8 and 24 months, with the highest prevalence between 10 and 18 months. The impact of feeding on the family and parent, as measured by the Feeding Impact Scales, was higher in families of children with problematic feeding than those without problematic feeding; however, given the small sample size, this was only statistically significant at 10 and 24 months.

Conclusions:

The prevalence of problematic feeding in this population of infants under 34 weeks was 43%–44% over the first 2 years of life. Infants born preterm should be considered at elevated risk for problematic feeding and monitored closely with timely referrals. Identifying prevention strategies in the neonatal intensive care unit will be critical.
Protocoles anesthésiques et prise en charge de la douleur chez les ruminants de compagnie
Authors: Bouaicha Faten
Published: December 2024

Les interventions chirurgicales de convenance ou dans un contexte pathologique sont des actes quotidiens pour les vétérinaires. Avec l’apparition d’un nouveau statut social pour les animaux de ferme, notamment petits camélidés et petits ruminants, le niveau d’exigence des propriétaires augmente. Le vétérinaire, garant du bien-être de l’animal, se doit de connaître les différents protocoles anesthésiques ainsi que les avantages et les limites de chacun. Aussi, les protocoles anesthésiques décrits peuvent avoir un degré d’analgésie insuffisant, d’où l’importance de les coupler à une bonne prise en charge de la douleur.

Nous abordons dans cet article les différents protocoles anesthésiques et analgésiques utilisés chez les petits ruminants et camélidés de compagnie.
Les arthrites chez les bovins
Authors: Robcis Rodolphe
Published: December 2024

Les arthrites chez le bovin sont un motif courant de consultation, avec pour signe premier d’appel une boiterie qu’il conviendra de caractériser. Dans les cas aigus, les quatre signes cardinaux de l’inflammation (rougeur, chaleur, gonflement, douleur) sont observables. Dans les cas les plus chroniques, une ankylose de l’articulation concernée associée à un remaniement majeur des aplombs sont à noter. Identifier l’origine la plus probable de l’arthrite présente un intérêt épidémiologique, mais permet également de traiter l’affection à la source quand il s’agit d’une arthrite consécutive à un phénomène bactériémique. Le recours aux examens complémentaires est utile dans le but de confirmer avec certitude le diagnostic, d’établir un pronostic et d’orienter vers la prise en charge la plus adaptée. Ces examens complémentaires incluent l’examen du liquide synovial (biochimie et cytologie), l’échographie et la radiographie de l’articulation en question.
Towards advanced forecasting of solar energetic particle events with the PARASOL model
Authors: Afanasiev Alexandr , Wijsen Nicolas , Vainio Rami
Published: December 2024

Gradual solar energetic particle (SEP) events are generally attributed to the particle acceleration in shock waves driven by coronal mass ejections (CMEs). Space-weather effects of such events are important, so there has been continuous effort to develop models able to forecast their various characteristics. Here we present the first version of a new such model with the primary goal to address energetic storm particle (ESP) events. The model, PARASOL, is built upon the PArticle Radiation Asset Directed at Interplanetary Space Exploration (PARADISE) test-particle simulation model of SEP transport, but includes a semi-analytical description of an inner (i.e., near the shock) part of the foreshock region. The semi-analytical foreshock description is constructed using simulations with the SOLar Particle Acceleration in Coronal Shocks (SOLPACS) model, which simulates proton acceleration self-consistently coupled with Alfvén wave generation upstream of the shock, and subsequent fitting of the simulation results with suitable analytical functions. PARASOL requires input of solar wind and shock magnetohydrodynamic (MHD) parameters. We evaluate the performance of PARASOL by simulating the 12 July 2012 SEP event, using the EUropean Heliospheric FORecasting Information Asset (EUHFORIA) MHD simulation of the solar wind and CME in this event. The PARASOL simulation has reproduced the observed ESP event (E ≲ 5 MeV) in the close vicinity of the shock within one order of magnitude in intensity.
Lewis Acid Catalyzed Regioselective Substitution of 2-Indolylmethanols with Pyrroles
Authors: Gao Jun-Nan , Tan Wen-Xin , Yang Shuang , Wang Da-Hua , Zhang Yu-Chen , Shi Feng , Wang Ning-Yi , Han Jiebin
Published: December 2024

A Lewis acid catalyzed regioselective C2′-electrophilic substitution of 2-indolylmethanols with pyrroles has been established, which affords indole-based tetraarylmethanes in overall high yields (up to 99%) with excellent regioselectivities. Moreover, such indole-based tetraarylmethanes exhibit potent cytotoxicity against HepG2 cancer cells, which demonstrates their potential applications in medicinal chemistry. This reaction not only represents the regioselective C2′-electrophilic substitution of 2-indolylmethanols with aryl nucleophiles (Ar-Nu), but also provides a new strategy for the synthesis of biologically important tetraarylmethanes.
Pseudocyst-Portal Vein Fistula with Hepatic Pseudocysts as Life-Threatening Complication of Pancreatitis: A Case Series with Review of Literature
Authors: Das Pritam , Thakur Dhruv , Borah Gourav Jyoti , Wodeyar Naganath Kashinath , Balankhe Kartik , Kumar S. Rakesh , Mohindra Samir
Published: December 2024

Pseudocyst-portal vein fistula (PPVF) manifesting as hepatic pseudocyst is a very rare vascular complication of pancreatitis. We present three cases of pancreatitis manifesting as PPVF with hepatic pseudocyst. One of them had a symptomatic pseudocyst with nonpatent portal vein with sepsis, which was managed with endoscopic drainage. The second case had a symptomatic pseudocyst with nonpatent portal vein without any manifestation of sepsis or gastrointestinal (GI) bleed, which was managed conservatively with gradual improvement. The third case manifested with sepsis with organ failure and GI bleed; portal vein reconstruction was planned, but the patient succumbed to sepsis. During a follow-up of 12 months, the first two patients had an uncomplicated course. Patency of the portal vein played a key role in determining the further course of treatment. In case of a nonpatent portal vein, endoscopic drainage may be preferred in case of symptomatic patients, whereas asymptomatic patients may be managed conservatively.
Superconducting glass with diagonal disorder
Authors: Pedan A. G. , Kulik I. O.
Published: December 2024

A model of the superconducting transition in a system with localized negative U pairing centers is studied in the limit U≫t (t is the width of the conduction band): the superconducting glass model. The critical temperature depends nonexponentially on the magnitude of the interaction U. However, the final expressions for the thermodynamic quantities presented differ little from the predictions of the standard BCS theory of superconductivity. A value of 2Δ0/Tc exceeding 4 is obtained and depends weakly on the electron concentration. The effect of diagonal disorder (spread in site energies) on the magnitude of Tc and the behavior of the system near the percolation threshold are examined. In contrast to the BCS model, the model of superconducting glass is extremely sensitive to the structural state of the lattice. The tunnel effect in superconducting glasses is examined and the accessible experimental information is discussed.
Characteristics of photoluminescence of antiferromagnetic KMnF3
Authors: Aksenov A. E. , Fedorov Yu. M. , Leksikov A. A.
Published: December 2024

The photoluminescence of KMnF3 is investigated in the range 10–100 °K. Its behavior in the interval 10–66°K is determined by the presence of three centers, which bum out in succession with increasing temperature, and above 60 °K the luminescence stems from a single center. A number of features, related to phase transitions occurring in KMnF3 in the temperature range 76–100 °K, were discovered in the temperature dependence of the intensity of its luminescence.
Magnetoacoustic electron resonances in ferromagnets with a periodic domain structure
Authors: Bass F. G. , Fal’ko V. L.
Published: December 2024

The propagation of ultrasound in ferromagnetic conductors with a periodic domain structure is investigated. A specific distribution of the magnetic induction B leads to the fact that, for electrons with a closed Fermi surface in the plane normal to B, trajectories passing through the whole domain structure are possible in addition to closed ones. The interaction of such electrons with a sound wave has a resonant character. The resonance occurs at a sound frequency ω given by ωres = nπΩ/2arcsin (α/2Rmax) (Ω = eB/mc; Rmax = Vf /Ω; a is the size of a domain; n = 1, 2 ...). In addition to the time resonance, the absorption coefficient undergoes geometric oscillations with a period smaller than 2Rmax and dependent on the size α.
Electrical conductivity and lateral focusing under charge carrier reflection from normal metal–superconductor boundaries
Authors: Bezuglyi E. V. , Korzh S. A.
Published: December 2024

We investigate the electrical conductivity and lateral focusing of charge carriers in a thin normal layer, in which current leads and potential contacts are located on the vacuum boundary, and its other surface borders a super-conductor (layered superconducting structure or the intermediate state of a type-I superconductor). It is shown that experimental study of these effects can yield useful information about the configuration of the n–s boundaries, as well as about the properties of the superconductor.
Acoustic echo at bubblons
Authors: Manykin É. A. , Ozhovan M. I. , Poluéktov P. P.
Published: December 2024

The coherent effect of acoustic echo at bubblons in liquid helium is investigated. It is shown that the coherent acoustic response signal yields complete information about the system of bubblons.
Capillary constant and surface tension of para-hydrogen and ortho deuterium over a wide temperature range
Authors: Baidakov V. G. , Khvostov K. V.
Published: December 2024

We have measured the capillary constant a2 and calculated the surface tension σ for para hydrogen, for hydrogen in equilibrium at 77 °K, and for ortho deuterium, using a differential capillary method over the temperature range 20.7 °K−0.96 Tc. We have studied the surface properties of hydrogen and deuterium as a function of the ortho–para composition. We propose simple equations which describe the temperature dependence of a2 and σ within the experimental error.
On the theory of quantum oscillation phenomena in cylindrical conductors
Authors: Nedorezov S. S.
Published: December 2024

The quantum energy levels and density of states for conduction electrons with a quadratic anisotropic dispersion law are obtained in a cylindrical conductor in an arbitrary magnetic field H. It is shown that the anisotropy of the Fermi surface causes localization of electron states with respect to the angle φ (in the cross section plane of the conductor). For not too low temperatures the data on the states govern quantum size oscillations of the electronic characteristics of the conductors. An analysis of the quantum oscillations of thermodynamic quantities is executed in weak magnetic fields. Oscillation frequencies equidistant in H are calculated for electrons in thin cylindrical bismuth single crystals.
ESR studies of atoms trapped in superfluid helium. I. Technique. ESR spectra of nitrogen atoms
Authors: Gordon E. B. , Pel’menev A. A. , Pugachev O. F. , Khmelenko V. V.
Published: December 2024

A low-temperature attachment to a standard ESR spectrometer for the investigation of atoms and radicals trapped in superfluid helium is described. The ESR spectra of nitrogen atoms in He II are obtained for the first time. An analysis of the spectra indicates that under the conditions for accumulation of nitrogen atoms in this work the trapped concentrations are low: [N]t/N2 ≳ 0.13%. These concentrations are still obtained when the temperature is increased to 4.2 °K. Annealing of the sample at T > 8 °K leads to reduction of its atom content.
On singularities of a superconductor order parameter due to an electronic topological phase transition
Authors: Makarov V. I.
Published: December 2024

It is shown that if the difference between the Fermi energy εF and the critical energy εK at which an electronic topological transition occurs takes a value in the energy range 0 ≤ | εF − εK | ≤ ωr under the effect of elastic lattice deformations, then two kinds of root singularities occur in the dependence of the superconductor order parameter Δ (p,ω) on the momentum p and the frequency ω is the characteristic frequency of the order of the boundary frequency of the phonon spectrum). The first kind of singularity in Δ (p,ω) is related to the fact that according to the Éliashberg equation, a layer of isoenergetic surfaces ε(p) = εF ± ω′ takes part in the formation of the function Δ (p,ω). The quantity ω′ varies over the range from zero to ωr If the surface ε(p) = εK is in this layer, then for a virtual change in the Fermi energy εF ± ω′ at the frequency ω′ = | εF − εK | an electronic topological transition occurs. The singularity in Δ(p,ω) indeed corresponds to this “virtual” topological transition, which exerts no influence on the properties of metals in the normal state. These singularities will be observed in a broad range of elastic stresses (pressures) satisfying the condition | εF − εK | ≲ ωr. The second kind of singularity is associated with the fact that the topology of the Fermi surface changes under the effect of elastic stresses. Then two new points of tangency of sections of the Fermi surface form ε(p + q) = εF (or old ones vanish) in the neighborhood of the point q + p = pk with the isoenergetic phonon surfaces ωλ (q) = ω (pk is the singular point on the surface ε(p) = εK at which V(pK) = ∇pε(p) = 0). In this case the singularities in Δ(p,ω) will be observed at pressures P ≳ P0. The pressure P0 corresponds to the condition β = | εF − εK | ≃ (Δ0m1/3S)2/3 (Δ0 is the magnitude of the energy gap in the superconductor, m is the mass of an electron, and S is the speed of sound).
Low-temperature absorption of a strong electromagnetic wave by electrons in a surface inversion layer
Authors: Glazman L. I.
Published: December 2024

We have determined the absorption of an electromagnetic wave and the carrier temperature in a thin inversion layer. We have studied the short pulse regime for a strong field as well as the cw regime. Two absorption mechanisms, related to scattering of carriers by a superlattice potential and by phonons (both bulk and surface), are analyzed. The latter mechanism may be the dominant one in the absence of a superlattice and when the surface is sufficiently homogeneous. The condition for lasing (in the absence of an external high frequency field) is determined for drift of the carriers along a surface superlattice.
Macroscopic quantum tunneling in a system with dissipation
Authors: Dmitrenko I. M. , Tsoi G. M. , Shnyrkov V. I.
Published: December 2024

A study of the fine structure of the high-frequency current-voltage characteristics of a SQUID in the temperature range from 4.2−0.5 °K has been carried out. The dependence found cannot be explained within the framework of existing ideas. It is concluded that dissipation increases the probability of macroscopic quantum tunneling in the system.
Nonlinear absorption of transverse sound in bismuth
Authors: Kukushkin V. A.
Published: December 2024

The deformation contribution to the nonlinear coefficient of absorption of transverse sound in bismuth is investigated in the case where the sound wavelength is much smaller than the electron mean free path. It is shown that the longitudinal electron current in the sound field is equal to zero, even though the sound attenuation is attributable to the longitudinal motion of particles. This effect is not specific to bismuth. The conditions for the experimental observation of nonlinear absorption of transverse sound in bismuth are analyzed.
Flux quantization effects in metal microcylinders in a tilted magnetic field
Authors: Brandt N. B. , Bogachek E. N. , Gitsu D. V. , Gogadze G. A. , Kulik I. O. , Nikolaeva A. A. , Ponomarev Ya. G.
Published: December 2024

Oscillatory phenomena of the type of “flux quantization” have been studied in normal microcylinders in a tilted magnetic field. It is shown that the oscillation period in the flux Φ = HπR2 (H is the magnetic field and R is the cylinder radius) increases with increasing field tilt angle θ relative to the cylinder axis according to a law ΔΦ = Φ0/cosΘ where Φ0 = hc/e is the flux quantum for a normal metal. The experimental data found in the present work agree with such a dependence, which allows us to interpret it as a manifestation of the Aharonov–Bohm effect in solids.
Photo-induced diffusion of copper atoms in crystalline xenon
Authors: Samovarov V. N. , Fugol’ I. Ya. , Khomenko S. N.
Published: December 2024

Diffusion of copper atoms in crystalline xenon is studied with specimens illuminated by light at frequencies lying within the impurity absorption band of isolated copper atoms. Experimental data on the change with time of the intensity of the impurity absorption band for resonant irradiation are used to determine the photo-induced diffusion coefficient D. It is established that at 10 °K and moderate pump radiation D > 1.8 · 10−17cm2/sec. The experimental results allow the conclusion that the elementary diffusion act is of an exchange nature.
Detection of an electric field temperature domain in a metal specimen
Authors: Tszyan Yu. N. , Logvinov I. I.
Published: December 2024

A negative differential conductivity regime is realized in indium and gallium rings in contact with liquid helium, permitting observation of formation of a temperature-induced electric field domain.
Stimulation of the weak ferromagnetic moment in an antiferromagnet by nonresonant magnetic and sound pumping
Authors: Seminozhenko V. P. , Sobolev V. L.
Published: December 2024

The effect of a nonresonant alternating magnetic field on the magnitude of the weak ferromagnetic moment of an antiferromagnet is investigated theoretically. It is shown that nonresonant parallel pumping leads to the stimulation of the weak moment. The analogous effect of increasing the weak moment in a nonequilibrium state relative to its equilibrium value at a given temperature is also possible by nonresonant sound pumping. Numerical estimates are presented for MnCO3 and α-Fe2O3.
Sound in films of solutions of two superfluid liquids
Authors: Adamenko I. N. , Poluéktov Yu. M.
Published: December 2024

Equations are derived for long-wave disturbances in films of solutions of two superfluid liquids. It is shown that two wave modes can propagate in such films, representing coupled oscillations of the film thickness, temperature, and concentration. Nonlinear simple third-sound waves are investigated with allowance for the contribution due to the finiteness of the temperature.
Surface tension of hydrogen isotopes and the quantum-mechanical law of corresponding states
Authors: Baidakov V. G.
Published: December 2024

Generalized expressions for the temperature dependence of the surface tension and the capillary constant of classical and semiquantum cryogenic liquids are obtained in terms of the law of corresponding states. The surface tension of all molecular compounds of hydrogen isotopes is calculated.
Magnetic interactions and phase transitions in crystals in the system Mn1−tFet As
Authors: Gribanov I. F. , Zavadskiĭ É. A. , Sivachenko A. P.
Published: December 2024

The magnetic properties of single crystals in the system Mn1−tFet As are investigated experimentally. It is established that under all variations in the external conditions (pressure, temperature, Fe concentration), an “easy surface” type of anisotropy occurs. A model is proposed for the magnetic ordering of the high-pressure phase, which has a spontaneous magnetic moment. The magnetic interactions in the isostructural alloys Mn1−t Tt As (T = V, Cr, Fe, Co, Ni), as well as in MnAs1−tPt are analyzed. It is shown that isotropic superexchange and exchange via the conduction electrons play the most important role in the formation of the observed magnetic structures, in particular, the double a-type spiral. The results obtained are used to interpret the effect of pressure and magnetic field on the magnetic behavior of the system studied.
Electron paramagnetic resonance in the low dimensional antiferromagnets CsMnCl3 · 2H2O and BaMnF4
Authors: Anders A. G. , Volotskii S. V.
Published: December 2024

We have studied the EPR spectrum of the quasi-one-dimensional system CsMnCl3 · 2H2O and quasi-two-dimensional BaMnF4 over a wide range of temperatures. In the immediate neighborhood of the Néel point a change is observed in the character of the critical broadening of the resonance line (a crossover), which indicates a change in the spin dynamics of these low dimensional systems. We discuss possible reasons for the change in the dynamics related to the influence of the weak exchange and interion anisotropy. It is shown that these mechanisms do not provide a quantitative description of the effect. We have studied the angular dependence of the width and shape of the resonant absorption line at low and high temperatures. In the EPR spectrum of CsMnCl3 · 2H2O a half-field satellite line is observed. These results are interpreted on the basis of models for the one- and two-dimensional structures, respectively, taking into account the changes in the spatial and temporal characteristics of the correlation functions.
Microcontact spectroscopy of magnons in rare earth metals
Authors: Akimenko A. I. , Verkin A. B. , Ponomarenko N. M. , Yanson I. K.
Published: December 2024

Microcontact spectra of Gd, Tb, and Ho in the ferromagnetic phase are studied. It is shown that the microcontact spectra are mostly proportional to the energy dependence of the magnon density of states, but for Tb and Ho phonon features are also observed. The anomalous microcontact spectra of Gd are studied; it is proposed that they relate to the quasiamorphous state of Gd. The thermal magnetic anomaly in microcontact spectra of Gd, Tb, Ho, and Dy is investigated.
On the effect of quasiparticle damping on the “gap” of a superconductor at the topological electron transition
Authors: Makarov V. I. , Yatsenko A. A.
Published: December 2024

The effect of scattering processes on the singularities of the order parameter Δ(p,ω) of a superconductor in the case when, under the action of external influences, the Fermi surface ε(p) = εF changes its topology at the critical energy εcr is investigated. It is shown that, for εF—εcr≲Δ the effect of the scattering processes on the root singularities of Δ(p,ω) is effectively [(εF —εcr)/ms2]1/2 times weaker (m is the electron mass and s is the velocity of sound). The Δ(p,ω) singularities that can be observed experimentally manifest themselves in the Fermi-surface-averaged quantity Δ(ω).
Dynamics of spin waves in parametric excitation by a stepped periodic magnetic field of arbitrary amplitude
Authors: Zvyagin A. A. , Serebryannyi V. Ya. , Frishman A. M. , Tsukernik V. M.
Published: December 2024

A magnon system is investigated under conditions of paramagnetic excitation by a longitudinal periodic magnetic field with a rectangular waveform of arbitrary amplitude. In contrast to the customary resonance approximation, the calculated growth rate is finite, and for sufficiently large linear damping parametric instability does not set in for any pump field.
Raman scattering study of the phase transition in potassium dysprosium tungstate
Authors: Popkov Yu. A. , Fomin V. I. , Pelikh L. N.
Published: December 2024

We have studied the Raman scattering spectrum of crystalline KDy(WO4)2 over the temperature range 2–300°K. Of the 36 Raman active vibrational modes predicted by group theoretical analysis, we have observed 34. No anomalies are observed in the behavior of the phonon spectrum at the phase transition (Tc =10 °K). This leads us to conclude that the phase transition takes place with preservation of the center of inversion and without multiplication of the unit cell volume. At low temperatures two additional lines are observed at frequencies of 10 and 135 cm−1 (T = 77 °K), which are absent in the spectrum of the isomorphic compound KY (WO4)2. These lines are attributed to the electronic transitions of the Dy3+ ion. In a detailed study of the low frequency line near the phase transition we observed a change in its spectral position (an increase of the frequency to 18 cm−1 at T = 2 °K) and its linewidth. All the properties of the behavior of this electronic transition are well decribed in terms of a model of the cooperative Jahn–Teller effect.
Internal friction in solid hydrogen
Authors: Gol’ter A. É. , Roshchupkin A. M.
Published: December 2024

The first results are given from experimental investigations of the frequency and temperature dependences of internal friction in solid hydrogen. These dependences are explained within the framework of the laws governing the thermally activated motion of defects.
Controllable non-Hermitian qubit–qubit coupling in superconducting quantum circuit
Authors: Wang Hui , Zhao Yan-Jun , Xu Xun-Wei
Published: December 2024

We propose a theoretical scheme to realize the controllable non-Hermitian qubit–qubit coupling by adding a high-loss resonator in a tunable coupling superconducting quantum circuit. By changing the effective qubit–qubit coupling, the phase and amplitude of resonator–qubit interaction, and the qubits’ quantum states, we can continually tune the energy level attraction, the position of EP (exceptional point), and the non-reciprocity in the non-Hermitian superconducting circuit. The EPs and non-reciprocity can affect the quantum states’ evolutions and exchange efficiencies for two qubits in the non-Hermitian superconducting circuit. The controllable non-Hermitian and non-reciprocal interactions between two qubits provide new insights and methods for exploring the unconventional quantum effects in superconducting quantum circuits.