bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic transport properties of two-dimensional tetragonal zinc chalcogenides
Authors: Zhu Yaoyun , Meng Shuang , Zhou Jia
Published: April 2023

The electronic transport properties of two-dimensional (2D) tetragonal ZnX (X = S, Se) monolayers have been studied using density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods.
Can we predict ambident regioselectivity using the chemical hardness?
Authors: Miranda-Quintana Ramón Alain , Vela Alberto , De Proft Frank , Martínez González Marco , Gázquez José L.
Published: April 2023

The hard/soft acid/base (HSAB) principle is a cornerstone in our understanding of chemical reactivity preferences.
Evolution of the full energy structure of Mn4+in fluoride phosphors under high pressure conditions
Authors: Leśniewski Tadeusz
Published: April 2023

In this paper the full energy structure of Mn4+under elevated pressure in a number of fluoride hosts is determined based on crystal field and Racah parameters obtained from high pressure optical spectra.
Relating band edge DOS occupancy statistics associated excited state electron entropy generation to free energy loss and intrinsic Voc deficit of solar cells
Authors: Huang Like
Published: April 2023

This work relates the band edge DOS occupancy statistics associated excited state electrons entropy generation to the intrinsic Voc loss of solar cells and puts forward the “band edge DOS engineering” as a new avenue towards photovoltaic performance improvement.
θ-[Mo8O26]4−-based multifunctional hybrid material for high catalytic performance on the cycloaddition of CO2, esterification and knoevenagel condensation
Authors: Zhang Zhengguo , Lv Hongxiao , Yang Kun , Zhang Xiutang
Published: April 2023

Aθ-[Mo8O26]4−-based hybrid material of [Cu2(BPPP)2]{θ-[Mo8O26]} (NUC-62) exhibits high catalytic performance on the cycloaddition of CO2with epoxides, esterification of aromatic acid and Knoevenagel condensation of aldehydes and malononitrile.
Sustainable keratin recovery process using a bio-based ionic liquid aqueous solution and its techno-economic assessment
Authors: Polesca Cariny , Al Ghatta Amir , Passos Helena , Coutinho João A. P. , Hallett Jason P. , Freire Mara G.
Published: April 2023

A sustainable process for keratin recovery from chicken feathers using a bio-based ionic liquid was developed. The minimum selling price calculated for keratin is 22 $ per kg, suitable for biomedical and cosmetic applications.
Light-initiated aggregation of gold nanoparticles for synergistic chemo-photothermal tumor therapy
Authors: Xia Huawei , Zhu Jinfeng , Men Changhe , Wang Anna , Mao Qiulian , Feng Yali , Li Jiachen , Xu Jingwei , Cheng Xiaju , Shi Haibin
Published: April 2023

The combination of chemotherapy with photothermal therapy (PTT) has attracted extensive attention due to its excellent synergetic effect attributing to the fact that hyperthermia can effectively promote the tumor uptake of chemotherapeutic drugs.
Rhodium-embedded UV photodetectors based on localized surface plasmon resonance on AlN/GaN
Authors: Hu Xun , Chen Baiyi , Huang Changfeng , Qiu Hongwei , Gao Na , Wu Yaping , Cai Duanjun , Huang Kai , Kang Junyong , Zhang Rong
Published: April 2023

We report a remarkably enhanced responsivity of metal–semiconductor–metal photodetectors embedded with a large-scale periodicity and highly uniform rhodium nanoparticle array based on localized surface plasmon resonance.
Inside a nanocrystal-based photodiode using photoemission microscopy
Authors: Cavallo Mariarosa , Alchaar Rodolphe , Bossavit Erwan , Zhang Huichen , Dang Tung Huu , Khalili Adrien , Prado Yoann , Silly Mathieu G. , Utterback James K. , Ithurria Sandrine , Dudin Pavel , Avila José , Pierucci Debora , Lhuillier Emmanuel
Published: April 2023

Photoemission microscopy applied to infrared nanocrystal photodiode.
Selection of an aggregation-caused quenching-based fluorescent tracer for imaging studies in nano drug delivery systems
Authors: Ji Xin , Cai Yifan , Dong Xiaochun , Wu Wei , Zhao Weili
Published: April 2023

In order to develop and optimize nano drug delivery systems (NDDSs), it is crucial to understand theirin vivofate.
Flexible multi-color electroluminescent devices with a high transmission conducting hydrogel and an organic dielectric
Authors: Yu Yongjie , He Kun , Xu Haibo , Xiao Zhen , Chen Liang , Xu Shiqing , Bai Gongxun
Published: April 2023

A flexible and color-changing AC luminescent device with wide color range was prepared by using a hydrogel as the electrode and nanoscale PVDF as the dielectric layer.
Comprehensive high-throughput screening of photopolymerization under light intensity variation using inline NMR monitoring
Authors: Ammini Gayathri Dev , Hooker Jordan P. , Van Herck Joren , Kumar Anil , Junkers Tanja
Published: April 2023

Continuous flow chemistry offers an exceptionally high degree of operational flexibility to handle photochemical transformations.
Designing Ce single-atom-sites coupled with CeO2 nanoparticles for oxygen reduction enhancement
Authors: Liu Jianping , Li Guijun , Xu Chuanlan , Chen Hongdian , Jin Rong , Sun Lingtao , Shu Chenyang , Chen Haifeng , Guo Chaozhong , Li Honglin , Si Yujun
Published: April 2023

This work proposed a novel supramolecular-gel-pyrolysis method to design a non-noble 3D porous CeO2/SACe-N–C composite that functioned as an efficient catalyst with dense Ce-N4O4|CeO2 coupling sites for the ORR in a zinc–air battery.
Engineering a non-noble plasmonic center in MOF-derived Z-scheme heterojunctions for enhanced photoelectrochemical water splitting
Authors: Li Chuanping , Hang Tianxiang , Zhou Hui , Ge Ping , Li Shuoren , Zhu Xian-Dong
Published: April 2023

A plasmonic Z-scheme catalyst is designed by the in situ derivation of NH2-MIL-125 and oxygen-vacancy engineering. The catalyst exhibits superior water oxidation activity in the PEC water splitting applications.
Recent advances in separation membranes based on porous organic molecular materials
Authors: Yu Saisai , Yang Miao , Liu Yuanhan , Liu Ming
Published: April 2023

This mini-review summarises the recent advances in separation membranes based on porous organic molecular materials, an emerging subclass of porous materials.
Efficient blue fluorescent OLEDs based on a D–π–A emitter with the hybridized localized and charge-transfer state
Authors: Xia Xin , Cao Wenjuan , Zhang Ming , Li Feng
Published: April 2023

We designed a D–π–A emitter, 4-(10-(4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)anthracen-9-yl)-N,N-diphenylaniline (TAZ-An-TPA), with TAZ, anthracene, triphenylamine (TPA) as acceptor, π-bridge and donor, respectively.
Completely non-fused ring acceptors with low non-radiative energy loss enabled by end-group modulation
Authors: Li Hao , Li Jiayao , Yang Chenyi , Wang Jingwen , Ryu Du Hyeon , Ma Lijiao , Yang Yi , Shin Won Suk , Zhang Shaoqing , Hou Jianhui
Published: April 2023

Four non-fused-ring electron acceptors with modified end groups, namely FC8-0F, FC8-1F, FC8-2F and FC8-2Cl, were designed and synthesized. Among them, the FC8-2Cl-based OSC exhibits a remarkable PCE of 13.28% with low energy loss.
Identification of PPT1 as a lysosomal core gene with prognostic value in hepatocellular carcinoma
Authors: Tian Wei , Li Chenyu , Ren Jiaqi , Li Pengfei , Zhao Jingyuan , Li Shuai , Dong Deshi
Published: April 2023

Hepatocellular carcinoma (HCC) is the most frequent cancer worldwide with a poor prognosis. Unfortunately, there are few reports on effective biomarkers for HCC, identification of novel cancer targets is urgently needed. Lysosomes are central organelles for degradation and recycling processes in cells, and how lysosome-related genes are involved in the progression of hepatocellular carcinoma remains unclear. The aim of the present study was to identify key lysosome-related genes affecting HCC. In the present study, lysosome-related genes involved in HCC progression were screened based on the TCGA (The Cancer Genome Atlas) dataset. Differentially expressed genes (DEGs) were screened, and core lysosomal genes were obtained in combination with prognostic analysis and protein interaction networks. Two genes were associated with survival, and their prognostic value was validated by prognostic profiling. After mRNA expression validation and IHC, the palmitoyl protein thioesterase 1 (PPT1) gene was identified as an important lysosomal-related gene. We demonstrated that PPT1 promotes the proliferation of HCC cells in vitro. In addition, quantitative proteomics and bioinformatics analysis confirmed that PPT1 acts by affecting the metabolism, localization, and function of various macromolecular proteins. The present study reveals that PPT1 could be a promising therapeutic target for the treatment of HCC. These findings provided new insights into HCC and identified candidate gene prognosis signatures for HCC.
Merging galaxy clusters in IllustrisTNG
Authors: Łokas Ewa L.
Published: April 2023

Mergers between galaxy clusters are an important stage in the formation of the large-scale structure of the Universe. Some of the mergers show a spectacular bow shock that formed as a result of recent passage of a smaller cluster through a bigger one, the classic example of this being the so-called bullet cluster. In this paper, I describe ten examples of interacting clusters identified among 200 of the most massive objects, with total masses above 1.4 × 1014 M⊙, from the IllustrisTNG300 simulation by searching for prominent bow shocks in their temperature maps. Despite different mass ratios of the two merging clusters, the events are remarkably similar in many respects. In all cases, the companion cluster passed close to the main one only once, between 0.9 and 0.3 Gyr ago, with the pericenter distance of 100–530 kpc and a velocity of up to 3400 km s−1. The subcluster, typically an order of magnitude smaller in mass than the main cluster before the interaction, loses most of its dark matter and gas in the process. The displacement between the collisionless part of the remnant and the bow shock is such that the remnant typically lags behind the shock or coincides with it, with a single exception of the merger occurring with the largest velocity. Usually about 1% of the gas cells in the merging clusters are shocked, and the median Mach numbers of these gas cells are around two. Due to the relatively small size of the simulation box, no close analog of the bullet cluster was found, but I identified one case that is similar in terms of mass, velocity, and displacement. The presented cases bear more resemblance to less extreme observed interacting clusters such as A520 and Coma.
Multi-scale relationship between coke gasification kinetics and its microstructure evolution in the blast furnace
Authors: Liu Qihang , Wang Di , Zhao Xiaowei , Yang Shuangping , Wu Keng
Published: April 2023

There is a precise theoretical correspondence between the microscopic chemistry and physical structure of coke and its apparent rate constantkreaand pore diffusion coefficientDeffof carbon loss process, and a certain precise mathematical relationship betweenkrea/Deffand the degradation gradient or degradation behavior of coke in blast furnace should exist. This is the key basis for predicting and evaluating coke degradation behavior in blast furnace through coke microstructure. In this work, the evolution relationship between the chemical and physical structure of coke and the macroscopic kinetic parameterskrea,Deffwas studied by gasification experiment of coke with different particle sizes. The results show that with the deepening of coke solution loss, minerals gradually precipitate on the surface of coke, and play a catalytic role in the process of solution loss, resulting in a decrease in activation energy and an increase inkrea. At this point, the micropores in coke expand and merge into mesopores and macropores, the diffusion path of CO2molecule decreases, the diffusion activation energy decreases, andDeffincreases gradually. In the middle and late period of solution loss, the active components in coke are consumed and the ash in coke is precipitated, which increases the activation energy and decreases thekrea. Moreover, the number of macropores in coke is further increased, and the tortuous degree of porous structure is greatly reduced, which leads to the decrease of diffusion activation energy and the increase ofDeff.krea/Deffrepresents the gradient reaction ability of coke on the macro level. The higher thekrea/Deffvalue, the greater the reaction gradient of coke under the same conditions, which further affects the degradation gradient and degradation behavior of coke in the blast furnace.
Evolution of inclusions in the whole process of GCr15 bearing steel
Authors: Xing Lidong , Bao Yanping , Wang Min
Published: April 2023

Inclusions have an important effect on the fatigue performance of bearing steels. Therefore, the study of the evolution of inclusions in the whole process and the reasonable control of inclusions (quantity, type, size, etc.) in steel can improve the production stability and fatigue performance of bearing steel. In this study, with the help of thermodynamic calculations and experimental studies, the evolution of the whole-process refining slag, oxygen and nitrogen content, and inclusions in bearing steel produced in a plant is systematically investigated. Overall, the refining slag composition of the refining process fluctuates less, and the oxygen content during LF refining and RH refining has been trending down, with an oxygen content of 5.7 × 10‒6 in the bearing steel billets. Although the cleanliness level is good for bearing steels, there is still room for improvement in refining slag composition, refining time, protected casting, and cut waste length.
Georacial Epidemiological Estimates of Glucose-6-Phosphate Dehydrogenase Deficiency among Newborns in the United States
Authors: Vidavalur Ramesh , Bhutani Vinod K.
Published: April 2023

Objective Glucose-6-phosphate dehydrogenase deficiency (G6PDd) is the most common inherited enzyme deficiency disorder worldwide and a major risk factor for the development of severe hyperbilirubinemia. Racial diversity of phenotypes and genotypes in affected individuals is likely to exist in the United States because of changing population demographics. The aim of the present study was to predict an empirical estimate of annual prevalence of G6PDd in newborns adjusted for geography (state of birth), maternal racial identity, and sex of the infant.

Study Design Birth statistics (2019) from National Center for Vital Statistics and CDC-WONDER data and race-specific prevalence of G6PDd in the United States were evaluated from published sources. We developed Simpson's diversity index (DI) for each State and correlated these to rates of G6PDd in neonates. Descriptive statistics including modeled prevalence and its association with DI were assessed using the Spearman's rho correlation test. We modeled state-specific prevalence for six states (California, Washington DC, Illinois, Massachusetts, New York, and Pennsylvania) using population-level allele frequencies and race, based on Hardy–Weinberg equilibrium.

Results We estimated 78,010 (95% confidence interval: 76,768–79,252) newborns had G6PDd at birth in 2019 with cumulative median prevalence of 17.3 (interquartile range: 12.4–23.2) per 1,000 live births for United States. A strong association was noted for DI and prevalence of G6PDd (p < 0.0005). Five states (Washington DC, Mississippi, Louisiana, Georgia, and Maryland) have the highest projected G6PDd prevalence, with a range of 35 to 48 per 1,000 live births. The probability of G6PDd for female heterozygotes, based on male prevalence, ranged from 1.1 to 7.5% for each cohort in the select six states.

Conclusion States with diverse populations are likely to have higher rates of G6PDd. These prevalence estimates exceeded by several-fold when compared with disorders screened by existing state mandated newborn screening panels. These discrepancies are further confounded by known risk of severe neonatal hyperbilirubinemia that results with G6PDd and the life-long risk of hemolysis. Combined universal newborn predischarge screening for G6PDd and bilirubin could alert and guide a clinician's practices for parental education and closer medical surveillance during the vulnerable neonatal time period.

Key Points
Pharmacy Students' Knowledge and Attitudes about Homeopathy: A Descriptive Survey Conducted in Turkey
Authors: Renda Gülin , Gökkaya İçim , Kandemir Gamze , Özyiğit Tuğçe , Kurt Tuğba
Published: April 2023

Background Homeopathy belongs to “Traditional and Complementary Medicine” (TCM) and is defined in the TCM regulation in Turkey as a holistic practice method that aims to improve health status with personalized medicines. The international and national literature includes a limited number of studies that examine individuals' knowledge, attitudes and behaviors toward homeopathy. Although in Turkey the Regulation on Pharmacists and Pharmacies states that the sale of homeopathic medicines is allowed only in pharmacies, no study was found that evaluated awareness about homeopathy among pharmacy students.

Objective The present study aims to assess pharmacy students' knowledge and attitudes toward homeopathy and to identify the factors that influence them.

Methods This descriptive study was conducted between December 1, 2021 and February 1, 2022 among the students of the Faculty of Pharmacy, Karadeniz Technical University (KTU), through a face-to-face survey. In total, 418 questionnaires suitable for data quality were included in the study. The SPSS 23.0 statistical program was used to analyze the data and the statistical significance level was taken as p < 0.05.

Results It was determined that 73% of the participants had heard about TCM practices and 55% had heard of homeopathy. Students in the fifth grade (p = 0.0001) and those working in an income-generating job (p = 0.026) were found to be those most aware of homeopathy. The students of the Faculty of Pharmacy correctly knew the basic working principles of homeopathy (p = 0.002). The source from which students obtained the most information about homeopathy was undergraduate courses. 80.4% of the participants thought that homeopathy should be applied by pharmacists. 47.0% of the students wanted to learn more about homeopathy or to carry out studies in the field of homeopathy in their careers.

Conclusion The results of this research revealed a high awareness amongst KTU pharmacy students about the practice of homeopathy.
Enhanced Clinical Decision-Making and Delivery of Minimally Invasive Care Using the ICCMS4D Integrated with Hands-Free Fluorescence-Based Loupes and a Chemomechanical Caries Removal Agent
Authors: Hiltch Gal , Steier Liviu , de Figueiredo José Antonio Poli
Published: April 2023

The purpose of this case report was to evaluate an approach for enhanced clinical decision-making while providing minimally invasive treatment, using the combined International Caries Classification and Management System (ICCMS 4D) with hands-free fluorescence-enhanced loupes (Reveal, Designs for Vision Inc., New York City, NY, United States) and a chemo-mechanical caries removal agent (Papacárie Duo Gel, Formula & Acao, Sao Paulo, Brazil). In recent decades, a shift towards a conservative approach to caries management has developed. The use of adequate operative techniques and correct decision-making are of paramount importance for early caries detection and tooth-preserving operative care. The use of noninvasive fluorescence-based adjuncts for enhanced diagnostic accuracy has gained popularity. Fluorescence describes the absorption of photons by a molecule, followed by its partial emission at a longer wavelength. Fluorescence detection of bacterial activity is largely based on the red/orange fluorescence emanating from bacterial metabolism, and has been shown to be found particularly in active caries and mature anaerobic plaque. The combined approach of using the standardized visual International Caries Detection and Assessment System (ICDAS) with fluorescence as an operative adjunct was shown to enhance the advantages of both systems. The approach may potentially increase detection sensitivity without compromising the specificity of the visual tactile method. A recent hands-free device is aimed to combine simultaneous diagnosis and therapy (theragnosis) using fluorescence, while overcoming possible obstacles to workflow continuity. The “Reveal” fluorescence-enhanced loupes are fitted with a dual white light/fluorescence light, and are said to allow the clinician to conduct any operational procedure with optional fluorescence guidance, from detection to caries removal, to treatment completion. Using the described method, a comprehensive pathway that emphasizes evidence-based information, correct clinical decision-making, and a minimally invasive therapeutic approach was proposed. The approach may represent a potential advancement in providing minimally invasive caries care.
Maternal Blood Fatty Acid Levels in Fetal Growth Restriction
Authors: Grohmann Raquel Margiotte , Marçal Vivian Macedo Gomes , Corazza Isabela César , Peixoto Alberto Borges , Júnior Edward Araujo , Nardozza Luciano Marcondes Machado
Published: April 2023

Objective: To assess the maternal blood levels of fatty acids (FAs) in pregnancies with fetal growth restriction (FGR).

Methods: This prospective cross-sectional study included pregnant women with gestational age between 26 and 37 + 6 weeks with FGR and appropriate for gestational age (AGA) fetuses. The levels of saturated, trans, monounsaturated, and polyunsaturated FAs were measured using centrifugation and liquid chromatography. The Student's t-test, Mann–Whitney test, and general linear model, with gestational age and maternal weight as covariants, were used to compare FA levels and the FGR and AGA groups. The Chi-square was used to evaluate the association between groups and studied variables.

Results: Maternal blood sample was collected from 64 pregnant women, being 24 FGR and 40 AGA. A weak positive correlation was found between the palmitoleic acid level and maternal weight (r = 0.285, p = 0.036). A weak negative correlation was found between the gamma-linoleic acid level and gestational age (r = − 0.277, p = 0.026). The median of the elaidic acid level (2.3 vs. 4.7 ng/ml, p = 0.045) and gamma-linoleic acid (6.3 vs. 6.6 ng/ml, p = 0.024) was significantly lower in the FGR than the AGA group. The palmitoleic acid level was significantly higher in the FGR than AGA group (50.5 vs. 47.6 ng/ml, p = 0.033).

Conclusion: Pregnant women with FGR had lower elaidic acid and gamma-linoleic acid levels and higher palmitoleic acid levels than AGA fetuses.
Electrical Status Epilepticus during Sleep: Risk Factors, Clinical Course, and Treatment Approaches
Authors: Aleksandrova Iliyana , Asenova Asya , Dimova Petia , Deneva Daniela , Rodopska Elena , Slavkova Elena , Bojinova Veneta
Published: April 2023

Background The efforts of clinicians are focused on determining the predictors for electrical status epilepticus in sleep (ESES) manifestation, due to the negative effect of ESES on cognition. Treatment approaches remain a leading problem because of therapeutic resistance.

Objective We looked for potential risk factors for ESES manifestation and summarize the clinical course and therapeutic approaches in patients with idiopathic and symptomatic ESES.

Patients and Methods We retrospectively reviewed the medical data of 51 children with idiopathic ESES and 20 children with symptomatic ESES.

Results We observed an earlier age of seizure onset (p = 0.0002) and a higher percentage of cases with multiple seizures (p < 0.00001) and with postictal paralysis (p < 0.00001) in idiopathic ESES compared with childhood epilepsy with centrotemporal spikes. In the idiopathic ESES, the treatment consisted of corticosteroids in patients with permanent ESES remission and transient remission, levetiracetam (LEV) children with permanent ESES remission and transient, clonazepam (CZP) children with permanent ESES remission and transient, ethosuximide (ESM), and sulthiame. The patients with symptomatic ESES had more unfavorable evolution, as 19 children had persistent or relapsing ESES course.

Conclusion We consider the earlier age of seizure onset (below 5 years) and the presence of multiple seizures and postictal paresis as risk factors for ESES manifestation. ESES is characterized by a significant therapeutic resistance, especially in the group of symptomatic cases. Good results are observed with LEV, ESM, CZP, and steroids.
Assessing human emotional responses to the design of public spaces around subway stations: a human factors research
Authors: Yang Liu , Zhu Yuan , Chatzimichailidou Mikela , Liu Xiaoyun
Published: April 2023

Transit-oriented development (TOD) is a powerful urban planning strategy to enhance sustainability and provide socioeconomic benefits for cities. The human-centered design of public spaces around subway stations is a critical issue in TOD. In this study, a socio-technical system-based perspective was adopted to investigate the impact of using different design strategies in public spaces around subway stations on human emotional responses. The novelty of this study lies in performing a human factors experiment to examine human emotional reactions to outdoor public spaces surrounding transit stations using a comprehensive method combining physiological assessment and subjective self-report. Thirty-four participants were recruited for the experiment, which was conducted at the catchment areas of two subway stations in Nanjing, China. Urban design characteristics related to open space enclosure and visual elements, natural elements, pedestrian access, surrounding buildings or walls, and land use and activities were tested in both semi-underground and above-ground public spaces. Additionally, human emotions were assessed using the pleasure, arousal, and dominance model and by investigating the four response systems that predominantly reflect people’s emotional states. These results led to design and policy suggestions that could assist practitioners and researchers in selecting relevant approaches for human-oriented and place-based TOD planning.

Graphical abstract
Folding the best bookmark with calculus
Authors: Piccone Ashley
Published: April 2023

A simple spiral notebook with a folded page demonstrates bifurcation and makes for a powerful education tool.
Magnetic perturbations of the Robin Laplacian in the strong coupling limit
Authors: Fahs Rayan
Published: April 2023

This paper is devoted to the asymptotic analysis of the eigenvalues of the Laplace operator with a strong magnetic field and Robin boundary condition on a smooth planar domain and with a negative boundary parameter. We study the singular limit when the Robin parameter tends to infinity, which is equivalent to a semi-classical limit involving a small positive semi-classical parameter. The main result is a comparison between the spectrum of the Robin Laplacian with an effective operator defined on the boundary of the domain via the Born–Oppenheimer approximation. More precisely, the low-lying eigenvalue of the Robin Laplacian is approximated by those of the effective operator. When the curvature has a unique non-degenerate maximum, we estimate the spectral gap and find that the magnetic field does not contribute to the three-term expansion of the eigenvalues. In the case of the disc domains, the eigenvalue asymptotics displays the contribution of the magnetic field explicitly.
Development and characteristics study of compact Penning ion source
Authors: Murtaza Ghulam , Siddique Muhammad Tariq , Shakeel-ur-Rehman
Published: April 2023

A compact-size Penning ion source with a small discharge volume (1.24 cm3) is developed. It consists of two concentric cylinders of different heights that act as cathodes and one hollow cylindrical anode. A homogeneous magnetic field is achieved within the discharge volume with geometrical optimization of the ion source. As a result, dense plasma is generated at low discharge power. The dynamics of the pulse mode discharge at low pulse width and frequency of anode voltage are studied. A high discharge (hundreds of amperes) current pulse with low delay time and fast rise time is recorded. The ion source is equally efficient to operate in continuous as well as pulse modes of ionization for various gases. It is operated in a wide range of low pressure at low anode voltage. An extraction system is designed to extract ions efficiently in the axial direction at a variable extraction voltage. The beam current of 200 µA in continuous mode and 6 A fast pulse in the pulsed mode of discharge have been measured. Variable beam current can be extracted with variable extraction voltage for any potential application.
Sonomechanobiology: Vibrational stimulation of cells and its therapeutic implications
Authors: Ambattu Lizebona August , Yeo Leslie Y.
Published: April 2023

All cells possess an innate ability to respond to a range of mechanical stimuli through their complex internal machinery. This comprises various mechanosensory elements that detect these mechanical cues and diverse cytoskeletal structures that transmit the force to different parts of the cell, where they are transcribed into complex transcriptomic and signaling events that determine their response and fate. In contrast to static (or steady) mechanostimuli primarily involving constant-force loading such as compression, tension, and shear (or forces applied at very low oscillatory frequencies ( ≤ 1 Hz) that essentially render their effects quasi-static), dynamic mechanostimuli comprising more complex vibrational forms (e.g., time-dependent, i.e., periodic, forcing) at higher frequencies are less well understood in comparison. We review the mechanotransductive processes associated with such acoustic forcing, typically at ultrasonic frequencies ( > 20 kHz), and discuss the various applications that arise from the cellular responses that are generated, particularly for regenerative therapeutics, such as exosome biogenesis, stem cell differentiation, and endothelial barrier modulation. Finally, we offer perspectives on the possible existence of a universal mechanism that is common across all forms of acoustically driven mechanostimuli that underscores the central role of the cell membrane as the key effector, and calcium as the dominant second messenger, in the mechanotransduction process.
Laboratory study of Kelvin–Helmholtz instability at ion kinetic scales
Authors: Zhang Xiao , Liu Yu , Lei Jiuhou , Huang Kexin , Jin Rong , Dang Tong
Published: April 2023

Kelvin–Helmholtz instability (KHI) is considered important in transporting energy and mass at the magnetopause of Earth and other planets. However, the ion kinetic effect influences the generation and evolution of KHI, as the spatial length of the magnetopause may be smaller than the Larmor radius of the ion; this influence is not yet fully understood. In this investigation, laboratory experiments were designed to study the excitation of KHI at the ion kinetic scale. The ion kinetic scale was modeled by controlling the ratio of the Larmor radius and the electric scale length ρ i / L E > 1, and the KHI was excited at the spatial scale of LE by a controllable sheared E × B flow. It was found that the ion kinetic effect on KHI growth manifests as the ion Larmor radius reaches the shear length scale, and the KHI is suppressed as the ion Larmor radius increases. Incorporating a theoretical analysis by substituting our experimental parameters, the suppression of the KHI was attributed to the fact that the KHI linear growth rate decreases with the ratio change of the ion Larmor radius because the relative orientations of the ion diamagnetic drift velocity ( V d) and the shear flow velocity ( V 0) are opposite. Our experimental conditions ( V d / V 0 < 0) are similar to the dusk-side conditions of the magnetospheres of Earth and Mercury under northward interplanetary magnetic fields; therefore, this result can be extended to understand the evolution of KHI in the planetary boundary layer.
Effect of surface potential pinning on strain behavior of AlGaN/GaN device structures
Authors: Blanton Eric W. , Prusnick Timothy A. , Green Andrew J. , Glavin Nicholas , Snure Michael
Published: April 2023

Understanding the varied strain effects in AlGaN/GaN devices is crucial for realizing optimized flexible electronics systems and strain sensors. Here, we report on the effects of surface potential pinning, altered by the deposition of device-relevant SiNx passivation and Ni gate layers, on the strain-dependent carrier density, ns, of AlGaN/GaN two-dimensional electron gas structures. Flexible van der Pauw samples were made by separating AlGaN/GaN layers from the sapphire growth substrate using a two-dimensional boron nitride van der Waals release layer and transferring them to flexible substrates. For bare surface samples, we observed relatively large decreases in ns with tensile strain (Δns of −2 × 1011 cm−2 at 0.1% uniaxial strain), indicating an unpinned AlGaN surface potential. For the SiNx and Ni covered samples, the ns-strain trends were nearly flat, indicating a more pinned surface potential. Additionally, sub-bandgap 400 nm light is shown to effectively pin the surface potential as evidenced by flattening the ns-strain trend, the mechanism of which we explain in terms of the persistent photoconductivity effect. These observations could have important implications in tuning strain sensors and minimizing device variability in flexible electronics.
The nanofluidic capacitor: Differential capacitance in the absence of reservoirs
Authors: Matse Mpumelelo , Berg Peter
Published: April 2023

Within the framework of the classical, mean-field Poisson–Boltzmann (PB) theory, we carry out direct numerical simulations to determine the differential capacitance of a closed nanochannel of a circular cross section, embedded in a polymeric host with charged walls and sealed at both ends by metal electrodes under an external potential bias. Our approach employs the modified PB equation, which accounts for the finite size of ions and the dependency of the electrolyte’s relative permittivity on the local electric field. In view of the absence of reservoirs, the modified PB equation becomes subject to global algebraic constraints, without prior knowledge of a bulk electrolyte concentration. Equilibrium ion distributions and differential capacitance curves are investigated as functions of electrolyte properties and the surface charge density modulation. This modulation leads to asymmetric differential capacitance curves that can be tuned. More generally, our approach provides a transparent numerical framework for accurately simulating confined nanofluidic systems with new physical properties that may be exploited in novel iontronic circuit elements.
Intelligent autoencoder for space-time-coding digital metasurfaces
Authors: Chen Xiao Qing , Zhang Lei , Cui Tie Jun
Published: April 2023

Space-time-coding (STC) digital metasurfaces provide a powerful platform for simultaneous spatiotemporal modulations of electromagnetic waves. Therefore, the fast and accurate generation of STC matrices based on desired harmonic scattering patterns can help STC metasurfaces enhance their practicality in various applications. Here, we propose a physics-driven vector-quantized (PD-VQ) intelligent autoencoder model that consists of an encoder, a vector-quantizer layer, and a physics-driven decoder. The physical operation mechanism between the STC matrix and the harmonic scattering pattern is introduced into the decoding module of the PD-VQ intelligent autoencoder, so that the autoencoder can be trained in an unsupervised manner without the need for large amount of manually labeled data. Taking a target harmonic scattering pattern as input, the trained PD-VQ autoencoder can quickly output the optimized discrete STC matrix, which takes only about 78 ms. We present a series of simulation examples to verify the reliability and accuracy of the proposed approach and also demonstrate its good generalization capability. Based on the proposed PD-VQ intelligent autoencoder, the STC digital metasurfaces enable agile multi-frequency harmonic beamforming.
Numerical simulation of flow-induced vibration of a circular cylinder close to a free surface at low Reynolds number
Authors: Qi Xiang , Dai Shaoshi , Ren Chengjiao , Dong Qianqian , Xiong Chengwang
Published: April 2023

The flow-induced vibration of a two-degree-of-freedom cylinder near a free surface at low Reynolds number (Re = 200) is numerically investigated using the lattice Boltzmann method and a free-surface model. The effects of the Froude number and submergence depth on the characteristics of the flow field and cylinder vibration are discussed. With the approach of the free surface, the wake behind the cylinder interacts with the free surface, resulting in a switch in the vortex shedding mode and the fluctuation of the free surface, which in turn affects the vibration of the cylinder. Additionally, a decrease in the normalized submergence depth h ∗ results in a decrease in the transverse amplitude of vibration and an increase in the streamwise amplitude. The topology of the cylinder vibration trajectory changes from a curve of eight to a teardrop, half-moon, or ellipse shape and gradually loses symmetry. Seven characteristic parameters are extracted from the trajectory of the cylinder, among which the amplitude of the vibration frequency and the phase difference of the vibration in different directions mainly affect the symmetry and topological structure of the trajectory.
Antenna bandwidth engineering through time-varying resistance
Authors: Mostafa M. H. , Ha-Van N. , Jayathurathnage P. , Wang X. , Ptitcyn G. , Tretyakov S. A.
Published: April 2023

The operational bandwidth of resonant circuits is limited by the resonator's size, which is known as the Chu limit. This limit restricts miniaturization of antennas, as the antenna bandwidth is inversely proportional to its size. Here, we propose slow time modulation of resistive elements to engineer bandwidth of small antennas. The temporal modulation of resistance induces virtual impedance that is fully controlled by the modulation parameters. We show how the virtual impedance can be used to optimize the frequency response of a resonant circuit, leading to enhanced matching at multiple frequencies simultaneously. We experimentally verify the proposed technique, demonstrating enhancement of radiation of a broadband modulated signal radiated by a small antenna.
A perspective on the doping of transition metal dichalcogenides for ultra-scaled transistors: Challenges and opportunities
Authors: Younas Rehan , Zhou Guanyu , Hinkle Christopher L.
Published: April 2023

To support the ever-growing demand for faster, energy-efficient computation, more aggressive scaling of the transistor is required. Two-dimensional (2D) transition metal dichalcogenides (TMDs), with their ultra-thin body, excellent electrostatic gate control, and absence of surface dangling bonds, allow for extreme scaling of the channel region without compromising the mobility. New device geometries, such as stacked nanosheets with multiple parallel channels for carrier flow, can facilitate higher drive currents to enable ultra-fast switches, and TMDs are an ideal candidate for that type of next generation front-end-of-line field effect transistor (FET). TMDs are also promising for monolithic 3D (M3D) integrated back-end-of-line FETs due to their ability to be grown at low temperature and with less regard to lattice matching through van der Waals (vdW) epitaxy. To achieve TMD FETs with superior performance, two important challenges must be addressed: (1) complementary n- and p-type FETs with small and reliable threshold voltages are required for the reduction of dynamic and static power consumption per logic operation, and (2) contact resistance must be reduced significantly. We present here the underlying strengths and weaknesses of the wide variety of methods under investigation to provide scalable, stable, and controllable doping. It is our Perspective that of all the available doping methods, substitutional doping offers the ultimate solution for TMD-based transistors.
Existence results for a class of p(x)-Kirchhoff-type equations with critical growth and critical frequency
Authors: He Rui , Liang Sihua
Published: April 2023

This article deals with a class of p(x)-Laplace equations with critical growth and critical frequency. By using the variational methods and some analytical skills, we obtain the existence and multiplicity of nontrivial solutions for this problem. The novelty of this paper lies in two aspects: (1) this equation contains the degenerate case, which corresponds to the Kirchhoff term K vanishing at zero and (2) our paper is about the appearance of critical terms, which can be viewed as a partial extension of the results of Zhang et al. [Electron. J. Differ. Equations 2018, 1–20] concerning the existence of solutions to this problem in the subcritical case.
Probe experiment on basic plasma parameter investigation in a quasi-gasdynamic ion source GISMO
Authors: Polyakov A. V. , Izotov I. V. , Skalyga V. A. , Vybin S. S. , Kiseleva E. M. , Bokhanov A. F.
Published: April 2023

Plasma parameters in a 28 GHz gasdynamic continuous electron cyclotron resonance discharge (ECR) with a high volumetric energy input were investigated with a Langmuir probe. The knowledge of the dependencies of plasma density and temperature on external parameters is useful for tuning the ECR source to the desired mode of operation. The design features of the plasma chamber and the configuration of the magnetic field made it possible to use the approximation a non-magnetized flat probe to calculate the temperature and electron density at various gas pressures and power of the heating microwave. A movable tungsten probe was used, allowing for studying plasma parameters along the magnetic field at various distances from the plasma electrode. At high powers, the electron density in the plug turned out to be close to the cutoff density (about 10 13   cm − 3). A fraction of warm ( > 30 eV) electrons, appearing at high powers, was found, which explains the formation of a pure proton beam in a number of experiments at the same facility. The abrupt increase in the temperature of the warm fraction with power was also found, which makes it of great interest to perform experiments on a multi-charged ions production in heavy gases.
Ultraviolet control of bacterial biofilms in microfluidic chips
Authors: Ramos Gabriel , Toulouze Clara , Rima Maya , Liot Olivier , Duru Paul , Davit Yohan
Published: April 2023

Polydimethylsiloxane (PDMS) microfluidic systems have been instrumental in better understanding couplings between physical mechanisms and bacterial biofilm processes, such as hydrodynamic effects. However, precise control of the growth conditions, for example, the initial distribution of cells on the substrate or the boundary conditions in a flow system, has remained challenging. Furthermore, undesired bacterial colonization in crucial parts of the systems, in particular, in mixing zones or tubing, is an important factor that strongly limits the duration of the experiments and, therefore, impedes our ability to study the biophysics of biofilm evolving over long periods of time, as found in the environment, in engineering, or in medicine. Here, we develop a new approach that uses ultraviolet-C (UV-C) light-emitting diodes (LEDs) to confine bacterial development to specific zones of interest in the flow channels. The LEDs are integrated into a 3D printed light guide that is positioned upon the chip and used to irradiate germicidal UV-C directly through the PDMS. We first demonstrate that this system is successful in controlling undesired growth of Pseudomonas aeruginosa biofilm in inlet and outlet mixing zones during 48 h. We further illustrate how this can be used to define the initial distribution of bacteria to perturb already formed biofilms during an experiment and to control colonization for seven days—and possibly longer periods of time—therefore opening the way toward long-term biofilm experiments in microfluidic devices. Our approach is easily generalizable to existing devices at low cost and may, thus, become a standard in biofilm experiments in PDMS microfluidics.
Water advancing and receding process as a liquid–vapor interface geometrical question
Authors: Yan ZeXiang , Wang ShengKun , Guan RunCheng , Guo Zeqi , Li ChenHui , Lv Xianglian , Yuan WeiZheng , He Yang
Published: April 2023

Existing wetting theories have difficulty accurately describing advancing/receding processes on micro-structured surfaces. A strategy is proposed to solve this problem by recognizing it as a liquid–vapor interface geometrical question. The wetting chip method is proposed to realize the microscopic observation of liquid–vapor interface variations. A wetting model based on the liquid–vapor interface shape (LVIS model) is established to describe the analytical relationships between the apparent contact angles, liquid–vapor interface radius, substrate geometry, and chemical nature of liquid. The LVIS model is divided into four typical time points and three transition stages, and its predictions agree with the experimental measurements. In contrast to traditional theories, the apparent contact angles in a quasi-equilibrium state should be separated into advancing and receding processes, and in this state, apparent contact angles vary with changes in the parameters of micro-pillar width and spacing. This strategy has the potential to accurately describe the wetting process on micro-structure surfaces.
Effects of doping and minority carrier lifetime on mid-wave infrared InGaAs/InAsSb superlattice nBn detector performance
Authors: Newell A. T. , Logan J. V. , Carrasco R. A. , Alsaad Z. M. , Hains C. P. , Duran J. M. , Ariyawansa G. , Balakrishnan G. , Maestas D. , Morath C. P. , Hawkins S. D. , Hendrickson A. , Webster P. T.
Published: April 2023

The effect of majority carrier concentration and minority carrier lifetime on the performance of mid-wave infrared ( λ cutoff = 5.5   μ m ) nBn detectors with variably doped InGaAs/InAsSb type-II superlattice absorbers is investigated. The detector layer structures are grown by molecular beam epitaxy such that their absorbing layers are either undoped, uniformly doped with a target density of 4 × 1015 cm−3, or doped with a graded profile, and variable-area mesa detector arrays are fabricated. Each material's temperature-dependent minority carrier lifetime is determined by time-resolved photoluminescence, and majority carrier concentration is extracted from capacitance–voltage measurements. Detector performance is evaluated with dark current and photocurrent measurements, from which quantum efficiency and shot-noise-limited noise-equivalent irradiance are calculated. The two doped detectors have lower dark current densities compared to their undoped counterpart due to the reduction in diffusion current as well as suppression of depletion current. Although both intentionally doped devices exhibit lower minority carrier lifetimes relative to the undoped device, the device with graded doping maintains a comparable quantum efficiency to the undoped device. Ultimately, the graded doping structure exhibits the highest sensitivity with a shot noise-limited noise-equivalent irradiance of 6.3 × 1010 photons/cm2 s in low-background light conditions, within a factor of 4× of an infrared detector pixel with Rule 07 dark current density and unity quantum efficiency. A detailed analysis of the dark current, quantum efficiency, and minority carrier lifetime provides insight into the material and device design factors that must be considered to realize a device with optimal sensitivity.