bluuebunny/crossref_metadata_2025 huggingface dataset:
Data Privacy and Security in Cloud Computing Environments
Authors: Maheswari J. Uma , Vijayalakshmi S. , N Rajiv Gandhi , Alzubaidi Laith H. , Anvar Khonimkulov , Elangovan R.
Published: July 2023

The globe has adopted the cloud computing environment, which organizes data and manages space for data storage, processing, and access. This technical development has brought up questions regarding data security and privacy in cloud computing environments, though. The purpose of this abstract is to offer a thorough review of the issues, solutions, and future developments related to data privacy and security in cloud computing. Keeping data private and secure while it is being processed and stored in outside data centres is the main difficulty in cloud computing systems. The abstract discusses the dangers of insider threats, data breaches, and illegal access to sensitive information. It digs further into the legal and compliance criteria that businesses must follow in order to protect user data in the cloud. In result, data privacy and security in cloud computing environments remain critical concerns for organizations and individuals alike. In the survey the overview of how to use cloud storage globally and its challenges, solution and future innovation is well explained. It underscores the importance of robust encryption, access controls, user awareness, and emerging technologies in safeguarding data in the cloud. By addressing these concerns, organizations can leverage the power of cloud computing while maintaining the confidentiality, integrity, and availability of their data.
Identification of Brain Tumor on Mri images with and without Segmentation using DL Techniques
Authors: TAM Akshaya , P PrasanthiSreeja , Jayashankari J. , Mohamed Aezeden , Iroda Sodikova , Vijayan V.
Published: July 2023

Brain cancer is a critical disease that results in the deaths of many individuals. Early detection and classification of brain tumors is essential for effective treatment and improved patient outcomes. However, current manual examination of MRI images for tumor detection can be time-consuming and imprecise. In this project, we propose a computer-based system that utilizes image processing techniques and convolutional neural networks (CNNs) for accurate and efficient brain tumor detection and classification. Our system involves several stages, including image pre-processing, segmentation, feature extraction, and classification. By training a CNN on a large dataset of MRI images with known tumor types, our system can accurately detect and classify brain tumors based on extracted features. The results of our experiments demonstrate the effectiveness of our systemin accurately detecting and classifying brain tumors, with potential to greatly improve the accuracy and speed of diagnosis, and ultimately lead to improved patient outcomes. To explicitly depict the tumor region, we have also added the segmentation procedure.
Employee Quality of Life in Office Automation Through Service Innovation: A Fuzzy Approach
Authors: Bharanitharan M. , Madhumita G.
Published: July 2023

Managers have to make different decisions about using different types of information at the same time. Managing the performance of employees and quality of life in printing industries and Information Technology Parks, individually or collectively is an important aspect of decision making. Effectively managing an organization's human resources and evaluating employees to support personal development, improved organizational performance, and input into the organization's strategy depend on performance appraisals. This is due to the absence of quantitative and systematic techniques. The problems include improper data, qualitative and quantitative measurements, and the performance evaluation is the main task for the industrial sectors. Fuzzy control is used to calculate the overall achievement index by aggregating the performance results for some selected parameters and presenting them as numerical values, which will certainly facilitate the evaluation of the appraisal calculation of the human resources staff. Consequently, the current research utilizes the characteristics of data technologies and provides a method to quantitatively and automatically assess employee performance in office automation. The results show that an independent aspect of workplace performance appraisal is the automated employee performance appraisal system.
DAF Extinguisher For On Road Vehicles
Authors: Vijayalakshmi G. , Narayanan R. Lakshmi , M Isravel , Pathak Shudhanshu , Azam Khalikov , Senthilkumar R.
Published: July 2023

A hardware-based variant known as an automatic fire extinguisher is used to put out fires when they start accidentally. Boards made of calcium silicate that can endure extremely high temperatures are used to coat the shield. Thermocouple ends are heated to a cut-off temperature, over which the robot begins responding to the fire, to change the robot's sensitivity to temperature. The biggest plus to this is that it automatically switches on when it senses a fire in its immediate vicinity using a thermocouple and moves in that direction in an attempt to put it out. In extreme situations, the temperature sensor acts as a backup for the thermocouple, as it detects fire or heating temperature the extinguishing agent is released and it flows through the solenoid valve for extinguishment of fire. Both life and property at the same instance of time. our system reduce the risk factors of rescuing life and property by immediately extinguishing the fire at first foremost the incident happens and the DAF EXTINGUISHER automatically does all the work and extinguishing the fire.
Sustainability achievement through the effective conversion of aquatic biomass into biofuel and its investigation in the CI engine
Authors: Rangasamy Krishnan , P Naveenchandran
Published: July 2023

Scientists are interested in biofuels because of their potential as a renewable energy source and alternative fuel. Biofuel has quickly become the industry standard because of the positive impact it has on the environment. The process of recycling materials into useful energy sources has grown in popularity in response to the significant increase in energy demand brought about by the worldwide population. Because of this, energy conversion via crassipes hydrophytes will be a hot topic in the near future. The production of biofuels from Crassipes hydrophytes has contributed greatly to re-establishing environmental equilibrium. Biofuel is the most advantageous feedstock for producing biodiesel, both monetarily and environmentally. Oxygenated fuels are a feasible option for reducing harmful exhaust fumes from motor vehicles. To achieve the goals of energy recovery from crassipes hydrophytes, this study provides an overview of biofuel as a potential alternative fuel for diesel engines. This study examines the efficiency and pollution levels of diesel engines running on biofuel blends generated from crassipes hydrophytes.
Experimental investigation on split type window Air conditioner using HFC and HC mixture as ecofriendly refrigerant alternate to HCFC-22
Authors: Karthik Ganapathi , Parthiban A. , Sasikumar C. , Krishnan B. Radha
Published: July 2023

This paper reports on an experimental study evaluating a window air conditioner's performance when R152a/R290/R600/R600a refrigerant mixture (by various mass percentages) is used as a possible alternative to R-22. Alternative refrigerants are local, cheap, and environmentally friendly. Unmodified R-22 window AC was charged with R152a/R290/R600/R600a. During the experiment, parameters such as coefficient of performance, refrigeration effect, pressure ratio, compressor discharge temperature, refrigerant mass flow rate, and compressor power are analyzed. The present work shows that R152a-15%/R290-15%/R600-35%/R600a-35% is the best-performing alternative refrigerant. Proposed blends and R22's performance were compared.
Performance Comparison of Tray, Bed and Integrated Drying Chamber in Closed Loop Heat Pump Dryer for Bermuda Grass
Authors: M Ashok Kumar , G Kumaresan , M Sivagaminathan , S Rajakarunakaran , R Siva Subramanian
Published: July 2023

Drying plays a crucial role in various industries such as food production, agriculture, Siddha, Ayurveda, and medical fields. To achieve controlled drying conditions, a heat pump dryer is considered an effective method, allowing for precise control of parameters like temperature, humidity, and air velocity. In this study, a heat pump dryer was designed and constructed to investigate the drying characteristics of Bermuda grass (Cynodon dactylon) at different velocities (1.5 m/s, 2.0 m/s, and 2.5 m/s) using three types of drying chambers: fluidized bed dryer, tray dryer, and combined dryer (a combination of bed and tray). The heat pump system utilized R134a as the refrigerant. The performance of the heat pump dryer in the three drying chambers was analyzed using Bermuda grass as the drying product. The Moisture Removal Rate (MRR) was calculated for various combinations of velocity and drying chamber, and it was observed that the combined dryer achieved a higher MRR at all three velocities compared to the tray and fluidized bed dryers.
Deep Learning Approach For Emotions Detection
Authors: Anupama  , Save Vibhuti , Biswas Ankur , Kumar Vinod , Lourens Melanie , Madhura K. , Sharma Anjali
Published: July 2023

The design and implementation of intelligent space, global, and healthcare arrangements have developed very essential since they automatically monitor both the surroundings and the individuals in it to offer support and facilities. Furthermost offer additional provision for the physical aspects of people at the cost of emotional aspects. For that reason, providing psychological and expressive healthcare is also imperative to advance excellence of life. Sentiment recognition is important and advantageous in social computer and social machine communication presentations as emotions specify mental state and requirements. Physiological signals-based emotion identification is a significant area of study with a bright potential for applications. Multiple HRV catalogs, comprising time-domain (MEAN, SDNN, and RMSSD) and frequency-domain (LFn, HFn, and LF/HF) indices were derived using RR intermission (RRI) time sequences that were recovered from ECGs. The most effective combination of ECG mood characteristics is chosen for classification using the Tabu Exploration Procedure(Happy, Sad and Fear). In order to categorize the test data, a deep convolutional neural system is finally created.
Early Postoperative Results in Robotic-Arm-Assisted Total Knee Replacement versus Conventional Technique: First Latin American Experience
Authors: Figueroa David , Guiloff Rodrigo , Prado Tomas , Figureoa Loreto , Sotomayor Juan Jose , Alarcon Alberto , Figueroa Francisco , Vaisman Alex , Calvo Rafael
Published: July 2023

Early results with robotic-arm-assisted total knee arthroplasty (TKA) are encouraging; nevertheless, literature might be unrepresentative, as it comes mostly from American, European, and Asian countries. There is limited experience and no comparative clinical reports in Latin America, a region of mainly low- and middle-income countries with limited access to these promising technologies. This study aims to compare the early postoperative results of the first Latin American experience with robotic-arm-assisted TKA versus conventional TKA. A cohort study was performed, including 181 consecutive patients (195 knees) with advanced symptomatic knee osteoarthritis (OA) undergoing primary TKA between March 2016 and October 2019. The cohort included 111 consecutive patients (123 knees) undergoing conventional TKA, followed by 70 consecutive patients (72 knees) undergoing robotic-arm-assisted TKA. The same surgical team (surgeon 1 and surgeon 2) performed all procedures. Patients with previous osteotomy, posttraumatic OA, and revision components were not considered. The same anesthetic and rehabilitation protocol was followed. The investigated clinical outcomes (for the first 60 postoperative days) were: surgical tourniquet time, time to home discharge, time to ambulation, postoperative daily pain (Visual Analog Scale), opioid use, range of motion, blood loss, complications, and postoperative mechanical axis. The early clinical postoperative results of this first Latin American comparative experience of robotic-arm-assisted TKA versus conventional technique showed lower opioids requirements and faster functional recovery of ambulation in those patients operated with the robotic system; nevertheless, surgical times were higher, without differences in total postoperative complications and other clinical outcomes.
Development of Novel Catalytic Direct Syntheses of N-Unsubstituted Ketimines and Their Applications to One-Pot Reactions
Authors: Morimoto Hiroyuki , Ohshima Takashi , Kondo Yuta
Published: July 2023

Herein, we summarize our recent efforts toward developing catalytic methods for the synthesis of N-unsubstituted ketimines and their applications to one-pot reactions for producing various nitrogen-containing compounds. This account provides detailed background, optimization, scope, and mechanistic information. We hope this work will stimulate future studies on the implementation of N-unsubstituted ketimines.

1 Introduction

2 Scandium-Catalyzed Synthesis of N-Unsubstituted Ketimines

3 Tetra-n-butylammonium Fluoride Catalyzed Synthesis of N-Unsubstituted Ketimines

4 Conclusion
Visible-Light-Driven Selenyl-Radical-Mediated Cascade Spirocyclization of 3-(2-Isocyanobenzyl)indoles with Diselenides
Authors: Qi Lin , Wang Li-Jing , Cao Tong-Yang , Dong Yi-Chen , Cao Jie-Hui
Published: July 2023

We present a facile, visible-light-driven, selenyl-radical-mediated, cascade spirocyclization of 3-(2-isocyanobenzyl)indoles with diselenides that affords various selenylated spiro[indole-3,3′-quinoline] derivatives under mild conditions. This protocol has good functional-group tolerance and a broad substrate scope; both diaryl and dialkyl diselenides are tolerated.
End-of-Life and Palliative Care Issues for Patients Living with Pulmonary Arterial Hypertension: Barriers and Opportunities
Authors: Ali Hyeon-Ju , Sahay Sandeep
Published: July 2023

Pulmonary arterial hypertension (PAH) is a progressive, incurable disease that results in significant symptom burden, health care utilization, and eventually premature death. Despite the advancements made in treatment and management strategies, survival has remained poor. End-of-life care is a challenging issue in management of PAH, especially when patients are in younger age group. End-of-life care revolves around symptom palliation and reducing psychosocial disease burden for a dying patient and entails advanced care planning that are often challenging. Thus, support from palliative care specialist becomes extremely important in these patients. Early introduction to palliative care in patients with high symptom burden and psychosocial suffering is suggested. Despite of the benefits of an early intervention, palliative care remains underutilized in patients with PAH, and this significantly raises issues around end-of-life care in PAH. In this review, we will discuss the opportunities offered and the existing barriers in addressing high symptom burden and end-of-life care issues. We will focus on the current evidence, identify areas for future research, and provide a call-to-action for better guidance to PAH specialists in making timely, appropriate interventions that can help mitigate end-of-life care issues.
Programmable dual-band acoustic topological insulator with dynamically movable interface states
Authors: Ge Yong , Shi Bin-jie , Xia Jian-ping , Sun Hong-xiang , Yuan Shou-qi , Xue Haoran , Zhang Baile
Published: July 2023

Topological acoustic interface states in one-dimensional (1D) acoustic topological insulators (ATIs) are zero-dimensional (0D) topological states localized at an interface. Unlike topological edge states that can propagate to deliver information in acoustic waveguides, the 0D topological interface states generally cannot serve as information carriers to deliver information from one location to another due to their intrinsic localization. Here, we design and demonstrate a 1D ATI with a movable interface, enabling the 0D topological acoustic interface states to deliver information from one location to another. The ATI design is based on two types of elemental building blocks—denoted as “1” and “0”—which are programmable. These elements of 1 and 0, when periodically arranged, can form topologically distinct crystals, whose interface hosts acoustic topological interface states in two bandgaps simultaneously. Since these two types of elements can switch from each other with external control, a programmable 1D dual-band ATI can be constructed. By programming coding sequences of 1 and 0 elements, we can observe dynamically movable 0D topological interface states riding on a moving interface along the 1D ATI in both bandgaps. Our work opens an avenue to develop topological acoustic devices with programmable and dynamic functions, which may have a variety of potential applications in the fields of energy trapping, topological pumping, information processing, and sound communication.
Diverse 3D auxetic unit cell inverse design with deep learning
Authors: Fang Xi , Shen Hui-Shen , Wang Hai
Published: July 2023

The use of metamaterial structures with auxeticity can result in exceptional mechanical properties, such as high energy absorption and fracture resistance. However, traditional design approaches rely heavily on researchers' subjective experiences, while existing inverse design methods limit design possibilities by ignoring generative diversity. In this study, we report a deep-learning-based inverse design approach for 3D auxetic unit cells that overcomes these limitations by providing diverse and accurately conditioned design options. We construct a dataset of symmetric 3D auxetic unit cells and apply an elastic modulus optimization network to generate diversified spatial topological structures with negative Poisson's ratios and optimized stiffness. The resulting 3D unit cells exhibit improved mechanical properties, as confirmed by finite element simulations and experiments. Our approach offers better coverage of the design space and generates optimized 3D unit cells with rich and diverse properties.
Hot electron preheat in hydrodynamically scaled direct-drive inertial confinement fusion implosions on the NIF and OMEGA
Authors: Rosenberg M. J. , Solodov A. A. , Stoeckl C. , Hohenberger M. , Bahukutumbi R. , Theobald W. , Edgell D. , Filkins T. , Betti R. , Marshall F. J. , Shah R. C. , Turnbull D. P. , Christopherson A. R. , Lemos N. , Tubman E. , Regan S. P.
Published: July 2023

Hot electron preheat has been quantified in warm, directly driven inertial confinement fusion implosions on OMEGA and the National Ignition Facility (NIF), to support hydrodynamic scaling studies. These CH-shell experiments were designed to be hydrodynamically equivalent, spanning a factor of 40 in laser energy and a factor of 3.4 in spatial and temporal scales, while preserving the incident laser intensity of 1015 W/cm2. Experiments with similarly low levels of beam smoothing on OMEGA and NIF show a similar fraction (∼0.2%) of laser energy deposited as hot electron preheat in the unablated shell on both OMEGA and NIF and similar preheat per mass (∼2 kJ/mg), despite the NIF experiments generating a factor of three more hot electrons (∼1.5% of laser energy) than on OMEGA (∼0.5% of laser energy). This is plausibly explained by more absorption of hot electron energy in the ablated CH plasma on NIF due to larger areal density, as well as a smaller solid angle of the imploding shell as viewed from the hot electron generating region due to the hot electrons being produced at a larger standoff distance in lower-density regions by stimulated Raman scattering, in contrast to in higher-density regions by two-plasmon decay on OMEGA. The results indicate that for warm implosions at intensities of around 1015 W/cm2, hydrodynamic equivalence is not violated by hot electron preheat, though for cryogenic implosions, the reduced attenuation of hot electrons in deuterium–tritium plasma will have to be considered.
Thermodynamic effects on nanobubble's collapse-induced erosion using molecular dynamic simulation
Authors: Ghoohestani Marzieh , Rezaee Sasan , Kadivar Ebrahim , el Moctar Ould
Published: July 2023

Using molecular dynamics simulation, we studied thermodynamic effects of a nanobubble's collapse-induced erosion occurring at different ambient temperatures. We analyzed the dynamics of a single nanobubble collapsing near an aluminum (Al) solid boundary immersed in water at temperatures ranging 10–60 °C (283–333 K). We used a momentum mirror protocol to investigate the nanobubble's collapse-induced shock wave as the associated nanojet formed and moved toward the solid boundary. The results showed that the nanojet was formed during the collapse process after the collision of the nanobubble with the shock wave. On the aluminum surface, the erosion at lower ambient temperatures was greater than at higher ambient temperatures.
Green's function integral method for pressure reconstruction from measured pressure gradient and the interpretation of omnidirectional integration
Authors: Wang Qi , Liu Xiaofeng
Published: July 2023

Accurately and efficiently measuring the pressure field is of paramount importance in many fluid mechanics applications. The pressure gradient field of a fluid flow can be determined from the balance of the momentum equation based on the particle image velocimetry measurement of the flow kinematics, which renders the experimental evaluation of the material acceleration and the viscous stress terms possible. In this paper, we present a novel method of reconstructing the instantaneous pressure field from the error-embedded pressure gradient measurement data. This method utilized the Green's function of the Laplacian operator as the convolution kernel that relates pressure to the pressure gradient. A compatibility condition on the boundary offers equations to solve for the boundary pressure. This Green's function integral (GFI) method has a deep mathematical connection with the state-of-the-art omnidirectional integration (ODI) for pressure reconstruction. As mathematically equivalent to ODI in the limit of an infinite number of line integral paths, GFI spares the necessity of line integration along zigzag integral paths, rendering generalized implementation schemes for both two and three-dimensional problems with arbitrary inner and outer boundary geometries while bringing in improved computational simplicity. In the current work, GFI is applied to pressure reconstruction of simple canonical and isotropic turbulence flows embedded with error in two-dimensional and three-dimensional domains, respectively. Uncertainty quantification is performed by eigenanalysis of the GFI operator in domains with both simply and multiply connected shapes. The accuracy and the computational efficiency of GFI are evaluated and compared with ODI.
A self-powered human gait monitoring sensor for osteoarthritis prevention
Authors: Ding Yunyi , Luo Yichen , Zhou Xue , Zhang Shaojie , Zhang Bin , Li Yayu
Published: July 2023

Recently, wearable sensors for human motion posture and medical diagnosis have received widespread attention. However, most wearable sensors rely on a power supply, and their preparation technology still faces limitations. Here, we used eyebrow powder to fabricate a triboelectric nanogenerator (E-TENG) for bio-mechanical energy harvesting and gait monitoring of patients with osteoarthritis. Under a maximum separation distance (5 mm) and a maximum motion frequency (6 Hz), the E-TENG device can attain a open-circuit voltage (Voc) of 169 V and a short-circuit current (Isc) of 5.5 µA. Meanwhile, the maximum output power of the E-TENG can arrive at 175 µW (load resistance: 20 MΩ). The E-TENG can detect human gait patterns (walking, running, and jumping), finger motion, and elbow joint movements. Further research has shown that the E-TENG can be used for gait recognition and monitoring in patients with osteoarthritis, providing reference data for osteoarthritis prevention and treatment. This research can promote the application of TENG devices based on cosmetic materials in medical diagnosis and adjuvant treatment.
System-, teacher-, and student-level interventions for improving participation in online learning at scale in high schools
Authors: Asanov Igor , Asanov Anastasiya-Mariya , Åstebro Thomas , Buenstorf Guido , Crépon Bruno , McKenzie David , Flores T. Francisco Pablo , Mensmann Mona , Schulte Mathis
Published: July 2023

Many school systems across the globe turned to online education during the COVID-19 pandemic. This context differs significantly from the prepandemic situation in which massive open online courses attracted large numbers of voluntary learners who struggled with completion. Students who are provided online courses by their high schools also have their behavior determined by actions of their teachers and school system. We conducted experiments to improve participation in online learning before, during, and right after the COVID-19 outbreak, with 1,151 schools covering more than 45,000 students in their final years of high school in Ecuador. These experiments tested light-touch interventions at scale, motivated by behavioral science, and were carried out at three levels: that of the system, teacher, and student. We find the largest impacts come from intervening at the system level. A cheap, online learning management system for centralized monitoring increased participation by 0.21 SD and subject knowledge by 0.13 SD relative to decentralized management. Centralized management is particularly effective for underperforming schools. Teacher-level nudges in the form of benchmarking emails, encouragement messages, and administrative reminders did not improve student participation. There was no significant impact of encouragement messages to students, or in having them plan and team-up with peers. Small financial incentives in the form of lottery prizes for finishing lessons did increase study time, but was less cost-effective, and had no significant impact on knowledge. The results show the difficulty in incentivizing online learning at scale, and a key role for central monitoring.
Mycoplasma DnaK increases DNA copy number variants in vivo
Authors: Benedetti Francesca , Silvestri Giovannino , Saadat Saman , Denaro Frank , Latinovic Olga S. , Davis Harry , Williams Sumiko , Bryant Joseph , Ippodrino Rudy , Rathinam Chozha V. , Gallo Robert C. , Zella Davide
Published: July 2023

The human microbiota affects critical cellular functions, although the responsible mechanism(s) is still poorly understood. In this regard, we previously showed that
Mycoplasma fermentans
DnaK, an HSP70 chaperone protein, hampers the activity of important cellular proteins responsible for DNA integrity. Here, we describe a novel DnaK knock-in mouse model generated in our laboratory to study the effect of
M. fermentans
DnaK expression in vivo. By using an array-based comparative genomic hybridization assay, we demonstrate that exposure to DnaK was associated with a higher number of DNA copy number variants (CNVs) indicative of unbalanced chromosomal alterations, together with reduced fertility and a high rate of fetal abnormalities. Consistent with their implication in genetic disorders, one of these CNVs caused a homozygous
Grid2
deletion, resulting in an aberrant ataxic phenotype that recapitulates the extensive biallelic deletion in the
Grid2
gene classified in humans as autosomal recessive spinocerebellar ataxia 18. Our data highlight a connection between components of the human urogenital tract microbiota, namely
Mycoplasmas
, and genetic abnormalities in the form of DNA CNVs, with obvious relevant medical, diagnostic, and therapeutic implications.
Threatened North African seagrass meadows have supported green turtle populations for millennia
Authors: de Kock Willemien , Mackie Meaghan , Ramsøe Max , Allentoft Morten E. , Broderick Annette C. , Haywood Julia C. , Godley Brendan J. , Snape Robin T. E. , Bradshaw Phil J. , Genz Hermann , von Tersch Matthew , Dee Michael W. , Palsbøll Per J. , Alexander Michelle , Taurozzi Alberto J. , Çakırlar Canan
Published: July 2023

“Protect and restore ecosystems and biodiversity”
is the second official aim of the current UN Ocean Decade (2021 to 2030) calling for the identification and protection of critical marine habitats. However, data to inform policy are often lacking altogether or confined to recent times, preventing the establishment of long-term baselines. The unique insights gained from combining bioarchaeology (palaeoproteomics, stable isotope analysis) with contemporary data (from satellite tracking) identified habitats which sea turtles have been using in the Eastern Mediterranean over five millennia. Specifically, our analysis of archaeological green turtle (
Chelonia mydas
) bones revealed that they likely foraged on the same North African seagrass meadows as their modern-day counterparts. Here, millennia-long foraging habitat fidelity has been directly demonstrated, highlighting the significance (and long-term dividends) of protecting these critical coastal habitats that are especially vulnerable to global warming. We highlight the potential for historical ecology to inform policy in safeguarding critical marine habitats.
RNA polymerase sliding on DNA can couple the transcription of nearby bacterial operons
Authors: Tenenbaum Debora , Inlow Koe , Friedman Larry J. , Cai Anthony , Gelles Jeff , Kondev Jane
Published: July 2023

DNA transcription initiates after an RNA polymerase (RNAP) molecule binds to the promoter of a gene. In bacteria, the canonical picture is that RNAP comes from the cytoplasmic pool of freely diffusing RNAP molecules. Recent experiments suggest the possible existence of a separate pool of polymerases, competent for initiation, which freely slide on the DNA after having terminated one round of transcription. Promoter-dependent transcription reinitiation from this pool of posttermination RNAP may lead to coupled initiation at nearby operons, but it is unclear whether this can occur over the distance and timescales needed for it to function widely on a bacterial genome in vivo. Here, we mathematically model the hypothesized reinitiation mechanism as a diffusion-to-capture process and compute the distances over which significant interoperon coupling can occur and the time required. These quantities depend on molecular association and dissociation rate constants between DNA, RNAP, and the transcription initiation factor
σ
70
; we measure these rate constants using single-molecule experiments in vitro. Our combined theory/experimental results demonstrate that efficient coupling can occur at physiologically relevant
σ
70
concentrations and on timescales appropriate for transcript synthesis. Coupling is efficient over terminator–promoter distances up to ∼1,000 bp, which includes the majority of terminator–promoter nearest neighbor pairs in the
Escherichia coli
genome. The results suggest a generalized mechanism that couples the transcription of nearby operons and breaks the paradigm that each binding of RNAP to DNA can produce at most one messenger RNA.
Discovery of charge order in a cuprate Mott insulator
Authors: Kang Mingu , Zhang Chao C. , Schierle Enrico , McCoy Stephen , Li Jiarui , Sutarto Ronny , Suter Andreas , Prokscha Thomas , Salman Zaher , Weschke Eugene , Cybart Shane , Wei John Y. T. , Comin Riccardo
Published: July 2023

Copper oxide superconductors universally exhibit multiple forms of electronically ordered phases that break the native translational symmetry of the CuO
2
planes. In underdoped cuprates with correlated metallic ground states, charge/spin stripes and incommensurate charge density waves (CDWs) have been experimentally observed over the years, while early theoretical studies also predicted the emergence of a Coulomb-frustrated ‘charge crystal’ phase in the very lightly doped, insulating limit of CuO
2
planes. Here, we search for signatures of CDW order in very lightly hole-doped cuprates from the 123 family
R
Ba
2
Cu
3
O

7 − 
δ

(
R
BCO;
R
: Y or rare earth), by using resonant X-ray scattering, electron transport, and muon spin rotation measurements to resolve the electronic and magnetic ground states fully. Specifically, Pr is used to substitute Y at the
R
-site to systematically suppress the superconductivity and access the extremely low hole-doping regime of the cuprate phase diagram without changing the oxygen stoichiometry. X-ray scattering data taken on Pr-doped YBCO thin films reveal an in-plane CDW order that follows the same linear evolution of wave vector versus hole concentration as oxygen-underdoped YBCO but extends all the way to the insulating and magnetically ordered Mott limit. Combined with the recent observation of charge crystal phase on an insulating surface of Bi
2
Sr
2
CaCu
2
O

8 + 
z

, our results in
R
BCO suggest that this electronic symmetry breaking is universally present in very lightly doped CuO
2
planes. These findings bridge the gap between the Mott insulating state and the underdoped metallic state and underscore the prominent role that Coulomb-frustrated electronic phase separation plays among all cuprates.
mthl1
, a potential
Drosophila
homologue of mammalian adhesion GPCRs, is involved in antitumor reactions to injected oncogenic cells in flies
Authors: Chen Di , Lan Xiao , Huang Xiaoming , Huang Jieqing , Zhou Xiaojing , Liu Jiyong , Hoffmann Jules A.
Published: July 2023

Injection of OCs into adult male flies induces a strong transcriptomic response in the host flies featuring in particular genes encoding bona fide G coupled proteins, among which the gene for
methuselah
like 1
is prominent. The injection is followed after a 3-d lag period, by the proliferation of the oncogenic cells. We hypothesized that through the product of
mthl1
the host might control, at least in part, this proliferation as a defense reaction. Through a combination of genetic manipulations of the
mthl1
gene (loss of function and overexpression of
mthl1
), we document that indeed this gene has an antiproliferative effect. Parallel injections of primary embryonic
Drosophila
cells or of various microbes do not exhibit this effect. We further show that
mthl1
controls the expression of a large number of genes coding for chemoreceptors and genes implicated in regulation of development. Of great potential interest is our observation that the expression of the mouse gene coding for the
adhesion G-protein-coupled receptor E1
(
Adgre1,
also known as
F4/80
), a potential mammalian homologue of
mthl1
, is significantly induced by B16-F10 melanoma cell inoculation 3 d postinjection in both the bone marrow and spleen (nests of immature and mature myeloid-derived immune cells), respectively. This observation is compatible with a role of this GPCR in the early response to injected tumor cells in mice.
Pumping iron: A multi-omics analysis of two extremophilic algae reveals iron economy management
Authors: Davidi Lital , Gallaher Sean D. , Ben-David Eyal , Purvine Samuel O. , Fillmore Thomas L. , Nicora Carrie D. , Craig Rory J. , Schmollinger Stefan , Roje Sanja , Blaby-Haas Crysten E. , Auber Robert P. , Wisecaver Jennifer H. , Merchant Sabeeha S.
Published: July 2023

Marine algae are responsible for half of the world's primary productivity, but this critical carbon sink is often constrained by insufficient iron. One species of marine algae,
Dunaliella tertiolecta
, is remarkable for its ability to maintain photosynthesis and thrive in low-iron environments. A related species,
Dunaliella salina
Bardawil, shares this attribute but is an extremophile found in hypersaline environments. To elucidate how algae manage their iron requirements, we produced high-quality genome assemblies and transcriptomes for both species to serve as a foundation for a comparative multiomics analysis. We identified a host of iron-uptake proteins in both species, including a massive expansion of transferrins and a unique family of siderophore-iron-uptake proteins. Complementing these multiple iron-uptake routes, ferredoxin functions as a large iron reservoir that can be released by induction of flavodoxin. Proteomic analysis revealed reduced investment in the photosynthetic apparatus coupled with remodeling of antenna proteins by dramatic iron-deficiency induction of TIDI1, which is closely related but identifiably distinct from the chlorophyll binding protein, LHCA3. These combinatorial iron scavenging and sparing strategies make
Dunaliella
unique among photosynthetic organisms.
Unveiling singlet oxygen spin trapping in catalytic oxidation processes using in situ kinetic EPR analysis
Authors: Wu Jing-Hang , Chen Fei , Yang Tian-Hao , Yu Han-Qing
Published: July 2023

Singlet oxygen (
1
O
2
) plays a pivotal role in numerous catalytic oxidation processes utilized in water purification and chemical synthesis. The spin-trapping method based on electron paramagnetic resonance (EPR) analysis is commonly employed for
1
O
2
detection. However, it is often limited to time-independent acquisition. Recent studies have raised questions about the reliability of the
1
O
2
trapper, 2,2,6,6-tetramethylpiperidine (TEMP), in various systems. In this study, we introduce a comprehensive, kinetic examination to monitor the spin-trapping process in EPR analysis. The EPR intensity of the trapping product was used as a quantitative measurement to evaluate the concentration of
1
O
2
in aqueous systems. This in situ kinetic study was successfully applied to a classical photocatalytic system with exceptional accuracy. Furthermore, we demonstrated the feasibility of our approach in more intricate
1
O
2
-driven catalytic oxidation processes for water decontamination and elucidated the molecular mechanism of direct TEMP oxidation. This method can avoid the false-positive results associated with the conventional 2D
1
O
2
detection techniques, and provide insights into the reaction mechanisms in
1
O
2
-dominated catalytic oxidation processes. This work underscores the necessity of kinetic studies for spin-trapping EPR analysis, presenting an avenue for a comprehensive exploration of the mechanisms governing catalytic oxidation processes.
Densified vertically lamellar electrode architectures for compact energy storage
Authors: Ju Zhengyu , Checko Shane , Xu Xiao , Calderon John , Raigama Kasun U. , Takeuchi Kenneth J. , Marschilok Amy C. , Takeuchi Esther S. , Yu Guihua
Published: July 2023

As one of the most compact electrochemical energy storage systems, lithium-ion batteries (LIBs) are playing an indispensable role in the process of vehicle electrification to accelerate the shift to sustainable mobility. Making battery electrodes thicker is a promising strategy for improving the energy density of LIBs which is essential for applications with weight or volume constraints, such as electric-powered transportation; however, their power densities are often significantly restricted due to elongated and tortuous charge traveling distances. Here, we propose an effective methodology that couples bidirectional freeze-casting and compression-induced densification to create densified vertically lamellar electrode architectures for compact energy storage. The vertically lamellar architectures not only overcome the critical thickness limit for conventional electrodes but also facilitate and redistribute the lithium-ion flux enabling both high rate capability and stable cyclability. Furthermore, this proposed methodology is universal as demonstrated in various electrochemical active material systems. This study offers a facile approach that realizes simultaneous high energy and high power in high-loading battery electrodes and provides useful rationales in designing electrode architectures for scalable energy storage systems.
Friction extrusion of AZ91/bioactive glass gradient composite
Authors: Motavallian Pourya , Rabiee Sayed Mahmood , Jamshidi Aval Hamed
Published: July 2023

The effect of the pre-friction extrusion microstructure of AZ91 billet on the microstructure, mechanical properties, and corrosion resistance of AZ91-bioactive glass surface composite rods was investigated. The results show that friction extrusion on AZ91 alloy billet with cast microstructure results in agglomerated bioactive glass particles in the composite rod microstructure. Compared to as-cast AZ91 alloy, friction extrusion on AZ91 alloy billet with cast microstructure results in 93% more corrosion resistance. Also, friction extrusion on AZ91 alloy billet with extruded microstructure leads to a gradient AZ91-bioactive glass composite rod with ultimate tensile strength, yield strength, and corrosion resistance of 9, 2, and 74% higher than AZ91 alloy rods, respectively.
Ultra high-speed single-molecule fluorescence imaging
Authors: Huang Zengxin , Kanchanawong Pakorn
Published: July 2023

In two articles in this issue, Fujiwara et al. developed an ultrasensitive high-speed camera capable of single-molecule fluorescence imaging at a microsecond timescale (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202110160). This major leap in detection speed enables the organization of plasma membrane and integrin-based adhesions to be probed in unprecedented detail (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202110162).
Bilevel inverse problems in neuromorphic imaging
Authors: Antil Harbir , Sayre David
Published: July 2023

Event or neuromorphic cameras are novel biologically inspired sensors that record data based on the change in light intensity at each pixel asynchronously. They have a temporal resolution of microseconds. This is useful for scenes with fast moving objects that can cause motion blur in traditional cameras, which record the average light intensity over an exposure time for each pixel synchronously. This paper presents a bilevel inverse problem framework for neuromorphic imaging. Existence of solution to the inverse problem is established. Second order sufficient conditions are derived under special situations for this nonconvex problem. A second order Newton type solver is derived to solve the problem. The efficacy of the approach is shown on several examples.
Edge passivation oxidation-enhanced spin caloritronics in zigzag blue phosphorus nanoribbons
Authors: Xu Jintao , Li Mingjun , Wang Qian , Zhang Xiaojiao , Fei Jiajia , Shi Yuechao , Zhang Bei , Long Meng-Qiu
Published: July 2023

In this study, the spin caloritronics of zigzag blue phosphorus nanoribbons (ZBPNRs) with edge hydrogenation and oxidation were studied using first-principles calculations and the non-equilibrium Green’s function method. Three different cases were considered: two edges of the ZBPNR were oxidized (2O-ZBPNR) and hydrogenated (2H-ZBPNR), one edge was oxidized, and the other was hydrogenated (HO-ZBPNR). Our results show that a perfect thermal spin filtering effect (SFE) and a negative differential thermoelectric resistance (NDTR) can be observed in structures with both 2O-ZBPNR and HO-ZBPNR, whereas these features were not found for 2H-ZBPNR. Furthermore, we confirmed that edge oxygen atoms in ZBPNRs offer different transport pathways for spin-up and spin-down states, leading to thermal SFE, and devices with oxygen-passivated ZBPNRs exhibited strong spin figures of merit (∼38) and large spin Seebeck coefficients (∼9 mV K−1).
State estimation of the dynamic behavior of plasma properties in a Hall effect thruster discharge
Authors: Troyetsky D E , Greve C M , Tsikata S , Hara K
Published: July 2023

The dynamic behaviors of the plasma properties in a Hall effect thruster discharge channel are estimated using a physics-constrained extended Kalman filter (PC-EKF) with a zero-dimensional global plasma model. The state estimates obtained using the global plasma EKF model are augmented by experimental data, in this case a discharge current signal. The use of state estimation allows for the determination of time-resolved plasma behaviors that may be difficult to measure experimentally, such as electron temperature and bulk velocity. The model is applied to investigate the plasma behavior at various thruster operating conditions, i.e. at varying discharge voltages and discharge currents. The estimated plasma properties are used to determine the classical electron collision frequency and the anomalous electron scattering frequency, which are shown to vary in time.
Optical properties of γ-sensing β-GaLaS3:Er crystal
Authors: Halyan V V , Yatcynyuk T K , Yukhymchuk V O , Virko S V , Lyaschuk Yu M , Valakh M Ya , Ivashchenko I A , Lebed O O , Skoryk M A , Litvinchuk A P
Published: July 2023

An erbium-doped β-GaLaS3 crystal has been grown by the solution-melt method, and the effect of γ-irradiation on their vibrational and radiative properties has been investigated. Experiments have demonstrated that the crystal is transparent in the near and mid-infrared (IR) regions (transparency ∼62% in the range of 350–7100 cm−1), which allows it to be used as an effective matrix for creating lasers in this spectral range. For the first time, the vibrational spectrum of the crystal and the density of phonon states have been calculated using the density-functional theory (DFT) method. Both the original and γ-irradiated β-GaLaS3:Er crystals were investigated by Raman and IR spectroscopy. It has been established that irradiation with a dose of up to 5000 Gray does not lead to structural changes in the crystals. The effect of the formed defects is more clearly manifested in the IR reflection spectra, compared to the Raman spectra. The mechanism of the occurrence of excited states and the emission of Er ions embedded in the lattice has been established, and the effect of γ-irradiation on the radiative properties of β-GaLaS3:Er due to the occurrence of radiation-induced defects has been analyzed. A model has been constructed that explains the Stokes and anti-Stokes radiation of the erbium ions in the crystal. It has been demonstrated that the grown crystal has good prospects for sensor and laser technology of the near and mid-IR ranges due to relatively high values of optical transparency and the intense radiative capacity of the erbium ions.
Equal-spin Andreev reflection in antiferromagnet/normal/superconductor junctions with Rashba spin–orbit coupling
Authors: Niu Zhi Ping , Zhang Yong Mei
Published: July 2023

We have theoretically investigated the Andreev reflection (AR)-induced conductance spectra through antiferromagnet/normal layer/superconductor junctions with hexagonal lattices. When the PT symmetry is broken by the staggered sublattice potential, antiferromagnet may exhibit spin polarization. A gap-edge conductance peak is usually shown, reflecting the characteristic of conventional AR. Equal-spin AR can be generated by the spin-flip scattering caused by Rashba spin–orbit coupling in the normal layer. Surprisingly, when the equal-spin AR process dominates, the conductance peak divides into two peaks near the singlet-gap energy, indicating the existence of spin-triplet pairings in the antiferromagnet. Furthermore, as the amplitudes of the conventional and equal-spin ARs can be modulated by the staggered sublattice potential and electrostatic potential, a conversion from the conductance peak to the conductance peak splitting can be realized, which can help us to distinguish between the spin-singlet and spin-triplet pairings. These findings make the antiferromagnet/superconductor junctions as promising platforms for future superconducting spintronics applications.