bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel and Practical Synthesis of Isavuconazonium Sulfate via Anion Exchange Resin
Authors: Huang Lei , Zhang Yi , Chen Hua , Wang Wei-Wei , Li Jian-Qi , Liu Yu
Published: July 2022

In this study, an efficient and practical process for the synthesis of isavuconazonium sulfate (compound 1), an antifungal agent, was described. Highlights in the synthesis route are the usage of the ion exchange resin instead of H2SO4 to introduce the HSO4
− anion in the formulation of quaternary ammonium salt (1), and the reaction condition was further optimized to facilitate the scale-up. The overall yield of the process was 57.0% and the high-performance liquid chromatography purity of product was 97.25%, which was higher than that of the reference-listed drug.
Predictors of 30-Day Pulmonary Complications after Video-Assisted Thoracoscopic Surgery Lobectomy
Authors: Holleran Timothy J. , Napolitano Michael A. , Duggan John P. , Peters Alex S. , Amdur Richard L. , Antevil Jared L. , Trachiotis Gregory D.
Published: July 2022

Background Pulmonary complications are the most common adverse event after lung resection, yet few large-scale studies have examined pertinent risk factors after video-assisted thoracoscopic surgery (VATS) lobectomy. Veterans, older and less healthy compared with nonveterans, represent a cohort that requires further investigation. Our objective is to determine predictors of pulmonary complications after VATS lobectomy in veterans.

Methods A retrospective review was conducted on patients who underwent VATS lobectomy from 2008 to 2018 using the Veterans Affairs Surgical Quality Improvement Program database. Patients were divided into two cohorts based on development of a pulmonary complication within 30 days. Patient characteristics were compared via multivariable analysis to determine clinical predictors associated with pulmonary complication and reported as adjusted odds ratios (aORs) with 95% confidence intervals. Patients with preoperative pneumonia, ventilator dependence, and emergent cases were excluded.

Results In 4,216 VATS lobectomy cases, 480 (11.3%) cases had ≥1 pulmonary complication. Preoperative factors independently associated with pulmonary complication included chronic obstructive pulmonary disease (COPD) (aOR = 1.37 [1.12–1.69]; p = 0.003), hyponatremia (aOR = 1.50 [1.06–2.11]; p = 0.021), and dyspnea (aOR = 1.33 [1.06–1.66]; p = 0.013). Unhealthy alcohol consumption was associated with pulmonary complication via univariable analysis (17.1 vs. 13.0%; p = 0.016). Cases with pulmonary complication were associated with increased mortality (12.1 vs. 0.8%; p < 0.001) and longer length of stay (12.0 vs. 6.8 days; p < 0.001).

Conclusion This analysis revealed several preoperative factors associated with development of pulmonary complications. It is imperative to optimize pulmonary-specific comorbidities such as COPD or dyspnea prior to VATS lobectomy. However, unhealthy alcohol consumption and hyponatremia were linked with development of pulmonary complication in our analysis and should be addressed prior to VATS lobectomy. Future studies should explore long-term consequences of pulmonary complications.
Awareness and Knowledge of Colorectal Cancer Screening Among Medical Students at the University of Aleppo: A Cross-Sectional Study
Authors: Zayegh Obada , Hmidi Zina Shikh , Nawlo Ahmad A , Al-Mouakeh Ahmad , Amin Basel , Banjah Bassel , Chammout Anwar , Alsayid Muhammad
Published: July 2022

Background Colorectal cancer (CRC) is the third leading cause of malignancy in Syria. The aim of our study was to assess the awareness and knowledge of CRC and its screening methods among medical students at the University of Aleppo.

Methods A cross-sectional study of medical students at the University of Aleppo was conducted using a self-administered 12-element questionnaire. The questionnaire consisted of demographics, awareness of CRC, knowledge of CRC and its screening methods. Awareness of CRC included three questions asking students if they ever heard of CRC and its screening methods. Knowledge of CRC was evaluated through three sets of questions about CRC risk factors, signs and symptoms, and preventative methods. The students were selected randomly during academic lectures. A χ
2 or Fisher's exact tests for categorical variables were used for statistical analysis, as appropriate. A two-sided p < 0.05 was considered statistically significant. We stratified students based on pre-clinical versus clinical years and average academic score.

Results A total of 824 students completed the questionnaire. The majority of students were aware of CRC (98.9%) and CRC screening methods (79.8%). Students had poor knowledge of CRC risk factors (16.5% for non-modifiable factors and 11.7% for modifiable factors), signs and symptoms (52.6%), and protective factors (9.9%). Only 31.7% of students were able to identify the appropriate age to initiate screening for average-risk individuals. Clinical students had better awareness and knowledge of CRC and its screening methods. Clinical students with higher academic score showed better awareness and knowledge in some elements.

Conclusion Our study reported high awareness and poor knowledge rates of CRC and its screening methods among medical students at the University of Aleppo. Although clinical students had higher awareness and knowledge of CRC compared to pre-clinical students, the impact of academic score revealed variable results.
Resumption of Antiplatelet Therapy after Major Bleeding
Authors: Geisler Tobias , Poli Sven , Huber Kurt , Rath Dominik , Aidery Parwez , Kristensen Steen D. , Storey Robert F. , Ball Alex , Collet Jean-Philippe , Berg Jurriën ten
Published: July 2022

Major bleeding is a common threat in patients requiring antiplatelet therapy. Timing and intensity with regard to resumption of antiplatelet therapy represent a major challenge in clinical practice. Knowledge of the patient's bleeding risk, defining transient/treatable and permanent/untreatable risk factors for bleeding, and weighing these against thrombotic risk are key to successful prevention of major adverse events. Shared decision-making involving various disciplines is essential to determine the optimal strategy. The present article addresses clinically relevant questions focusing on the most life-threatening or frequently occurring bleeding events, such as intracranial hemorrhage and gastrointestinal bleeding, and discusses the evidence for antiplatelet therapy resumption using individual risk assessment in high-risk cardiovascular disease patients.
Angina Outcomes in Secondhand Smokers: Results from the National Health and Nutrition Examination Survey 2007–2018
Authors: Chaar Suzanne , Yoon Jeik , Abdulkarim Joud , Villalobos José , Garcia Jeanette , López Castillo Humberto
Published: July 2022

Objective The aim of the study is to examine the relationship between secondhand smoke (SHS) and angina using the National Health and Nutrition Examination Survey database over a 12-year period.

Methods Self-reported smoking status and cotinine levels were used to identify exposure groups (smokers, nonsmokers, and secondhand smokers), and medical history of angina was also collected via a self-report survey. The association between exposure to SHS and angina was analyzed using odd ratios with 95% confidence intervals calculated using two logistic regression models.

Results The study found that when aggregating data from all 12 years, secondhand smokers are 42.9% significantly more likely to report having experienced angina, while smokers were 97.7% significantly more likely to report having angina compared with nonsmokers.

Conclusions This study is the first of its kind to examine data from a national database over a 12-year period to determine an association between SHS and angina outcomes, thus highlighting the importance of reducing SHS exposure to improve cardiovascular health.
Lipid-Based Nanocarrier Systems for Drug Delivery: Advances and Applications
Authors: Zhao Yan-Qi , Li Li-Jun , Zhou Er-Fen , Wang Jiang-Yue , Wang Ying , Guo Lin-Miao , Zhang Xin-Xin
Published: July 2022

Lipid-based nanocarriers have been extensively investigated for drug delivery due to their advantages including biodegradability, biocompatibility, nontoxicity, and nonimmunogenicity. However, the shortcomings of traditional lipid-based nanocarriers such as insufficient targeting, capture by the reticuloendothelial system, and fast elimination limit the efficiency of drug delivery and therapeutic efficacy. Therefore, a series of multifunctional lipid-based nanocarriers have been developed to enhance the accumulation of drugs in the lesion site, aiming for improved diagnosis and treatment of various diseases. In this review, we summarized the advances and applications of lipid-based nanocarriers from traditional to novel functional lipid preparations, including liposomes, stimuli-responsive lipid-based nanocarriers, ionizable lipid nanoparticles, lipid hybrid nanocarriers, as well as biomembrane-camouflaged nanoparticles, and further discussed the challenges and prospects of this system. This exploration may give a complete idea viewing the lipid-based nanocarriers as a promising choice for drug delivery system, and fuel the advancement of pharmaceutical products by materials innovation and nanotechnology.
Do subcultures play a role in facilitating academic quality?—A case study of a Saudi higher education institution
Authors: Aldhobaib Meshal Abdulaziz
Published: July 2022

This study aims to examine the relationship between various subcultures present in a higher education institution and the facilitation and realisation of academic quality criteria. Via a qualitative ethnographic approach consisting of in-depth interviews, observations and document analyses of a single higher education institution, it presents evidence of a type of subgroup (termed the quality subgroup) that has emerged in the targeted academic programmes. This quality subgroup has a positive impact on accomplishing academic quality criteria. In the same vein, the study highlights other types of subgroups that have a negative impact on such criteria. The findings underline a range of theoretical implications relating to organisational culture, subcultures and culture-quality theory and methodology. They also present a range of practical implications, most importantly, how the quality subgroup members work on quality standards and how they succeed in listing their academic programmes for academic accreditation. Finally, the findings of the study shed light on vital features and changes in the Saudi higher education institutions’ working environments (due to critical legal and social changes) that contribute to cultural studies and human resource practices in Saudi organisations. Such practical implications are argued to advance higher education institutions’ policies and management. A comprehensive discussion of the study theory and practical implications is included in the conclusion section.
Toward a terrestrial biogeographical regionalisation of the world: historical notes, characterisation and area nomenclature
Authors: Morrone Juan J. , Ebach Malte C.
Published: July 2022

An interim hierarchical classification (i.e. biogeographical regionalisation or area taxonomy) of the world’s terrestrial regions is provided, following the work of Morrone published in Australian Systematic Botany in 2015. Area names are listed according to the International Code of Area Nomenclature so as to synonymise redundant names. The interim global terrestrial regionalisation to the subregion level recognises 3 kingdoms, 2 subkingdoms, 8 regions, 21 subregions and 5 transition zones. No new names are proposed for the regions; however, Lydekker’s Line is renamed Illiger’s Line. We note that some regions still require area classification at the subregion level, particularly the Palearctic, Ethiopian and Oriental regions. Henceforth, the following interim global regionalisation may be used as a template for further revisions and additions of new areas in the future.
Monitoring methods influence native predator detectability and inferred occupancy responses to introduced carnivore management
Authors: Jessop Tim S. , Gillespie Graeme R.
Published: July 2022

Context Management actions that suppress introduced predator densities can benefit the population recovery of native species. Nevertheless, ensuring that predator management produces measurable population-level benefits can be influenced by multiple factors affecting species detection. Monitoring designs using multiple survey methods may perform better than increasing sampling effort with single-method protocols. Aims This study aimed to estimate individual and cumulative detection probabilities and site occupancy estimates from the use of five different monitoring methods to survey a native mesopredator, the lace monitor (Varanus varius). Second, we assessed the effect of lethal red fox (Vulpes vulpes) baiting on lace monitor detection probabilities and site occupancy estimates collected from each monitoring method. Methods Multi-method sampling for Varanus varius occurred at 76 sites across lethal fox baited and non-baited habitats in East Gippsland, Victoria. Bayesian site occupancy models were used to estimate the effects of detection method and fox-baiting treatments on Varanus varius detection probability and site occupancy. Key results Method-specific detection probabilities (P = 0.00–0.12) and site occupancy estimates (Ψ = 0–0.53) varied considerably among methods, but combinations of multi-method monitoring improved lace monitor detection probability (P = 0.11–0.18) and site occupancy (Ψ = 0.87 ± [0.66–0.93]−0.91 ± [0.76–0.97] mean ± [95% credible intervals]) above any single method. However, there was extreme heterogeneity in the size and direction of the introduced predator baiting effect on method-specific lace monitor detection. Three methods (box traps and two different visual search surveys) all indicated lace monitor detection probabilities increased in fox-baited sites. However, sand pads reported a decrease in lace monitor detection at fox-baited sites, whereas pipe traps obtained no detections. Conclusions Combining detection data from all methods led to the inference of a positive fox-baiting effect, albeit with a smaller magnitude and better certainty than that estimated using a reduced method monitoring design, which had fewer detection data after excluding biased detection from sand pads. Implications Using a multi-method monitoring approach improved lace monitor detection and reduced sampling effort. However, depending on sampling methodology, the management effects on lace monitors can change.
Characterisation of AlCrCuFeMox high entropy alloys for nuclear fuel cladding
Authors: Zhu Xincheng , Tao Zhenrui , Wang Chunji , Zhang Yanwei , Bai Guanghai , Lan Rui
Published: July 2022

High entropy alloys (HEAs) have great potential used for accident-tolerant fuel (ATF) due to their excellent properties. The ATF properties of AlCrCuFeMo x HEAs were systematically investigated. The AlCrCuFeMo x had the typical dendrite morphology and Cu and Al elements segregated in the interdendrite region. After 1200°C water vapour oxidation, compact and continuous α-Al2O3 oxide film formed on the surface and effectively protected the inner from further oxidation. When x = 1, the HEA had the best oxidation resistance (59 mg/dm2 weight gain after 1 h), two orders lower than that of the traditional Zr-1Nb alloy for nuclear fuel cladding. Under normal operation water condition, the performance of the present HEAs is not as good as Zr-1Nb due to the segregation of Cu and dispersed Al2O3 formed on the surface.
Assessing the health and ecological security of a human induced watershed in central iran
Authors: Sadeghi Seyed Hamidreza , Vafakhah Mehdi , Moosavi Vahid , Pourfallah Asadabadi Sanaz , Sadeghi Padideh Sadat , Khaledi Darvishan Abdulvahed , Bagheri Fahraji Reza , Mosavinia Seyed Hossein , Majidnia Abdolghasem , Gharemahmudli Sudabeh , Rekabdarkolaei Hamidreza Moradi
Published: July 2022

Assessment of the watershed health and associated ecological security is crucial for the proper land resources management, notably when sufficient money and time have lacked. The present study aimed to prepare health and ecological security for the Pishkuh Watershed in Yazd Province, central Iran. To prepare the health atlas of the Pishkuh Watershed, the conceptual framework of pressure, state, response (PSR) was employed. The pressure index was investigated by analyzing the driving forces of natural and human-induced factors. Then, the existing conditions of the natural environment and the watershed performance were analyzed using the state index. Besides, the response index was also calculated as a criterion for expressing the degree of community response or different watershed outcomes to the driving forces imposed on the watershed system. The study results revealed that some 91 and 9% of the watershed were classified as moderately healthy and relatively unhealthy. The results of the ecological security index further showed that some 41% of the area was categorized as relatively poor status. The results of the current study can be used by local managers and decision-makers to adaptively designate appropriate, economic, and goal-targeted solutions for the resources management in the region.
Self-consistent equation for torsion arising as a consequence of the Dirac sea quantum fluctuations in external classical electromagnetic and gravitational fields
Authors: Vergeles S N
Published: July 2022

The quantum fluctuations of the Dirac field in external classical gravitational and electromagnetic fields are studied. A self-consistent equation for torsion is calculated, which is obtained using one-loop fermion diagrams.
FeynGrav: FeynCalc extension for gravity amplitudes
Authors: Latosh B
Published: July 2022

Package ‘FeynGrav’ which provides a framework to operate with Feynman rules for gravity within ‘FeynCalc’ is presented. We present a framework to deal with Feynman rules for general relativity and non-supersymmetric matter minimally coupled to gravity. Applicability of the package is tested with 2 → 2 on-shell tree level graviton scattering, polarization operators, and one-loop scalar-gravitational interaction structure.
Decoherence effects in quantum nondemolition measurement induced entanglement between Bose–Einstein condensates
Authors: Gao Shuai , Ilo-Okeke Ebubechukwu O , Mao Yuping , Kondappan Manikandan , Aristizabal-Zuluaga Juan E , Ivannikov Valentin , Byrnes Tim
Published: July 2022

We study the robustness of quantum nondemolition (QND) measurement induced entanglement between Bose–Einstein condensates (BECs). We consider an experimental scheme where two BECs are placed in the paths of a Mach–Zehnder interferometer, and a QND interaction creates entanglement between coherent light and the atoms. We analyze the two dominant channels of decoherence, atomic dephasing and photon loss on the entangled states produced by this scheme. We calculate the effect of dephasing on the variance and expectation values of the spin operators, entanglement and correlation criteria. Our analysis does not use the Holstein–Primakoff approximation, and is capable of modelling long light–atom interaction times, producing non-Gaussian states beyond the two-mode squeezed states. In the presence of dephasing, the entangled states are robust in the macroscopic limit as long as the dimensionless interaction time is less than

1
/

N

, where N is the number of atoms in the BEC. For photon loss, the entangled states generated by long interaction times show a remarkable robustness that makes the scheme promising for various quantum information applications.
A review of recent progress on directional metasurfaces: concept, design, and application
Authors: Chen Ke , Feng Yijun
Published: July 2022

Metasurfaces have provided a new paradigm to control electromagnetic waves by manipulating the spatially varying distribution of subwavelength artificial structures across the interface. Directional metasurfaces, a kind of metasurface with direction-dependent properties, possess different wave functionalities upon the incidence wave coming from opposite directions. The diversified wave-manipulation capabilities of directional metasurfaces show advantages of compactness, flatness, scalability, direction-dependence, etc, exhibiting promising potentials for a plethora of applications. Here, we present a review on the recent progress of directional metasurfaces, including the concept origin, the practical realization of meta-structures, the design method for direction-dependent wavefront tailoring, and the application aspects of directional metasurfaces. In the conclusion, we present possible further research directions in this field based on our own perspectives.
Photonic spin Hall effect in symmetrical structure containing Dirac semimetal materials
Authors: Qi Song , Da Haixia , Yan Xiaohong
Published: July 2022

Three-dimensional Dirac semimetal (3DDS) has attracted wide attraction due to its adjustable thickness and Fermi energy. However, the performance of photonic spin Hall effect in the structures with 3DDS is still unknown. In this work, we establish a symmetrical structure composed of the periodic 3DDS and Si to study the dependence of spin shift on the thickness and Fermi energy of 3DDS. We find that the magnitude and the position of the spin shift can be controlled by either the thickness or Fermi energy of 3DDS, whose maximum positive and negative spin shifts can reach up to

11.57
λ

and

−
8.29
λ

when the thickness of 3DDS, the Fermi energy, the repetition number of 3DDS and Si and the beam waist are

100

nm

,

0.15
 

eV

, 4 and

30
λ

, respectively. The enhanced spin shift is excited by surface plasmon resonance and the response of

r

s

/

r

p

with the incident angle can explain when and why the spin shift peak (valley) appears. In addition, the control of the repetition number of (3DDS-Si)
N
and (Si-3DDS)
N
is an effective way to adjust the magnitude and the position of the spin shift peak (valley). The realization of large and tunable spin shift in the symmetrical structure containing Dirac semimetal shows its great potential in the application of sensors, switches and optoelectronic devices.
Ligand-metal bonding effects in resonance enhanced x-ray Bragg diffraction
Authors: Lovesey S W , van der Laan G
Published: July 2022

Chlorine covalently bonded to an open shell metal is present in many materials with desirable or intriguing physical properties. Materials include highly luminescent nontoxic alternatives to lead halide perovskites for optoelectronic applications K2CuCl3 and Rb2CuCl3, enantiomorphic CsCuCl3 that presents magneto-chiral dichroism at a low temperature, and cubic K2RuCl6 that possesses a singlet ground state generated by antiparallel spin and orbital angular momenta. Structural chirality of CsCuCl3 has been confirmed by resonant x-ray Bragg diffraction. We explore likely benefits of the technique at the chlorine K-edge using a symmetry informed method of calculation applied to chlorine multipoles. Already, a low energy feature in corresponding x-ray absorption spectra of many compounds has been related to the chlorine-metal bond. Bragg diffraction from chlorine in cubic K2RuCl6 is treated in detail. Diffraction patterns for rhombohedral compounds that present space-group forbidden Bragg spots are found to be relatively simple.
Methods of improving brain dose estimates for internally deposited radionuclides
*
Authors: Leggett Richard W , Tolmachev Sergei Y , Avtandilashvili Maia , Eckerman Keith F , Grogan Helen A , Sgouros George , Woloschak Gayle E , Samuels Caleigh , Boice Jr John D
Published: July 2022

The US National Council on Radiation Protection and Measurements (NCRP) convened Scientific Committee 6–12 (SC 6–12) to examine methods for improving dose estimates for brain tissue for internally deposited radionuclides, with emphasis on alpha emitters. This Memorandum summarises the main findings of SC 6–12 described in the recently published NCRP Commentary No. 31, ‘Development of Kinetic and Anatomical Models for Brain Dosimetry for Internally Deposited Radionuclides’. The Commentary examines the extent to which dose estimates for the brain could be improved through increased realism in the biokinetic and dosimetric models currently used in radiation protection and epidemiology. A limitation of most of the current element-specific systemic biokinetic models is the absence of brain as an explicitly identified source region with its unique rate(s) of exchange of the element with blood. The brain is usually included in a large source region called Other that contains all tissues not considered major repositories for the element. In effect, all tissues in Other are assigned a common set of exchange rates with blood. A limitation of current dosimetric models for internal emitters is that activity in the brain is treated as a well-mixed pool, although more sophisticated models allowing consideration of different activity concentrations in different regions of the brain have been proposed. Case studies for 18 internal emitters indicate that brain dose estimates using current dosimetric models may change substantially (by a factor of 5 or more), or may change only modestly, by addition of a sub-model of the brain in the biokinetic model, with transfer rates based on results of published biokinetic studies and autopsy data for the element of interest. As a starting place for improving brain dose estimates, development of biokinetic models with explicit sub-models of the brain (when sufficient biokinetic data are available) is underway for radionuclides frequently encountered in radiation epidemiology. A longer-term goal is development of coordinated biokinetic and dosimetric models that address the distribution of major radioelements among radiosensitive brain tissues.
On-site calibration method of the AACMM based on a high-precision CNC machine tool
Authors: Wang Wen , Sun Jiahuan , Sun Tao , Lu Keqing , Yang He , Chen Zhanfeng , Wang Chuanyong , Weng Yixin , Cui Xueguang
Published: July 2022

An articulated arm coordinate measuring machine (AACMM) is a kind of instrument used to test workpieces in the industrial field, and its measurement uncertainty depends on the on-site environmental factors to a certain extent. If there is a problem with the AACMM during on-site testing, it needs to be re-calibrated to ensure the measurement uncertainty. In this work, a fast on-site calibration method for the AACMM is proposed using a high-precision computer numerical control (CNC) machine tool. The AACMM is fixed on the machine tool table. The calibration artifact is clamped on the machine tool spindle. This calibration artifact can move to any point in the global space of the AACMM along with the operation of the spindle. Then, a virtual calibration artifact with calibration points is achieved using the CNC machine tool. The positions of these points are calculated using the improved Hammersley sequence. The calibration method using a high-precision CNC machine tool is experimentally verified through the single-point articulation performance test of ASME B89.4.22-2004 and the length measurement test of ISO 10360-12. The calibration method proposed in this work only uses an on-site high-precision CNC machine tool, one of the most common machines in many industrial fields, as the calibration instrument for the AACMM calibration. No extra equipment is required, which is convenient and beneficial to calibrate the AACMM. In addition, the CNC machine tool can construct different kinds of virtual structures for the AACMM calibration, such as virtual rods, virtual circles, virtual balls and even non-uniform 3D artifacts with complex curved surfaces. This may give rise to many novel calibration methods and further improve the calibration accuracy.
Calibration of line-structured light vision sensors based on simultaneous polarization imaging
Authors: Zhu Zhenmin , Zhao Yan , Liu Shibin , Liu Yongjie , Wang Wu , Tang Liang
Published: July 2022

Stray light from line-structured light vision sensors easily interferes with the center extraction accuracy of a structured light strip. In this paper, a high-accuracy calibration technique using polarized beam splitting simultaneous imaging is proposed. First, two polarization component images with different polarization directions are obtained through a single measurement. The method overcomes problems related to stray light and errors caused by the shaking of the instruments. Therefore, false polarization information can be avoided in this way. Second, an image fusion algorithm is used to improve the imaging quality of the light bar. Experiments are performed to show that the light strips no longer have local overexposure, and the calibration accuracy of the system is improved.
Cu2O/Ti3C2T
x
nanocomposites for detection of triethylamine gas at room temperature
Authors: Zhou Ming , Yao Yu , Han Yutong , Xie Lili , Zhu Zhigang
Published: July 2022

Triethylamine gas is one of the harmful volatile organic compounds for human health and the ecological environment. Therefore, in order to prevent the detrimental effects of triethylamine gas, it has greatly requirement to be accurately detected. Unfortunately, Cu2O has a low triethylamine gas response and slow recovery. Because of this, we prepared Cu2O/Ti3C2T
x
nanocomposites by a facile ultrasonication technique. Cu2O is uniformly dispersed on the surface and interlayers of multilayer Ti3C2T
x
to form a stable hybrid heterostructure. The optimized Cu2O/Ti3C2T
x
nanocomposite sensor’s response to 10 ppm triethylamine at room temperature is 181.6% (∣
R
g-R
a
∣/R
a × 100%). It is 3.5 times higher than the original Cu2O nanospheres (52.1%). Moreover, due to the characteristics of high carrier migration rate and excellent conductivity of Ti3C2T
x
, the response recovery rate (1062 s/74 s) of Cu2O/Ti3C2Tx composites is greatly improved than pristine Cu2O (3169 s/293 s). In addition, Cu2O/Ti3C2T
x
nanocomposites sensor also shows excellent repeatability, outstanding selectivity, and long-term stability. Thus, the Cu2O/Ti3C2T
x
nanocomposites sensor has broad application prospects for detecting triethylamine gas at room temperature.
Prediction of negative refraction in Dirac semimetal metamaterial
Authors: Da Haixia , Song Qi , Hu Pengya , Ye Huapeng
Published: July 2022

Negative refraction materials are indispensable building blocks in the optoelectric devices for their unique functionalities of controlling the light propagations, such as, superlens and transformation optics. However, material realizations of negative refraction are still limited to the conventional metals, semiconductors as well as magnetic materials. Here, we show that three dimensional Dirac semimetals have the opportunity to enable the negative refraction, which can be achieved through alternatively stacking three dimensional Dirac semimetals and the dielectric layers together. It is found that the effective perpendicular and parallel permittivities in this multilayered stack display the respective negative and positive values over a certain frequency region, which enables its negative group refractive angle and it can be controlled by the Fermi energy of Dirac semimetals. The spectra of transmittance in the multilayered structure for transverse magnetic wave also reveals an incident angle-independent transmittance dip, which originates from the zero value of the real part of the effective perpendicular permittivity. Our findings unveil the essential role of three dimensional Dirac semimetals in producing the negative group refraction responses and promise their applications in the metamaterial-based devices.
Nano-graphite field-emission cathode for space electric propulsion systems
Authors: Kleshch Victor I , Ismagilov Rinat R , Mukhin Vsevolod V , Orekhov Anton S , Filatyev Alexander S , Obraztsov Alexander N
Published: July 2022

Improving the thruster efficiency is a crucial challenge for the development of space electric propulsion systems, especially advanced air-breathing thrusters utilizing the surrounding rarefied atmosphere as fuel. A significant reduction in thruster power consumption can be achieved by using field emission (FE) cathodes that do not require heating and have the highest energy efficiency. In this work, we study FE from nano-graphite thin films, consisting of carbon nanostructures with a high aspect ratio, and demonstrate their suitability for use in the space electric propulsion systems. The films shown appropriate FE characteristics in a wide range of gas pressures at high current loads in constant and pulsed operation modes. Based on the obtained experimental results, nano-graphite cathodes were employed for the design of an electron gun with increased reliability and minimized energy losses associated with electron extraction. The possibility of using such a gun in a specific air-breathing satellite operating in low Earth orbits is demonstrated.
Applications of artificial intelligence in stereotactic body radiation therapy
Authors: Mancosu Pietro , Lambri Nicola , Castiglioni Isabella , Dei Damiano , Iori Mauro , Loiacono Daniele , Russo Serenella , Talamonti Cinzia , Villaggi Elena , Scorsetti Marta , Avanzo Michele
Published: July 2022

This topical review focuses on the applications of artificial intelligence (AI) tools to stereotactic body radiation therapy (SBRT). The high dose per fraction and the limited number of fractions in SBRT require stricter accuracy than standard radiation therapy. The intent of this review is to describe the development and evaluate the possible benefit of AI tools integration into the radiation oncology workflow for SBRT automation. The selected papers were subdivided into four sections, representative of the whole radiotherapy process: ‘AI in SBRT target and organs at risk contouring’, ‘AI in SBRT planning’, ‘AI during the SBRT delivery’, and ‘AI for outcome prediction after SBRT’. Each section summarises the challenges, as well as limits and needs for improvement to achieve better integration of AI tools in the clinical workflow.
Genuine multipartite entanglement subject to the Unruh and anti-Unruh effects
Authors: Wu Shu-Min , Zeng Hao-Sheng , Liu Tonghua
Published: July 2022

We study the acceleration effect on the genuine tripartite entanglement for one or two accelerated detector(s) coupled to the vacuum field. Surprisingly, we find that the increase and decrease in entanglement have no definite correspondence with the Unruh and anti-Unruh effects. Specifically, Unruh effect can not only decrease but also enhance the tripartite entanglement between detectors; also, anti-Unruh effect can not only enhance but also decrease the tripartite entanglement. We give an explanation of this phenomenon. Finally, we extend the discussion from tripartite to N-partite systems.
Inferring Markovian quantum master equations of few-body observables in interacting spin chains
Authors: Carnazza Francesco , Carollo Federico , Zietlow Dominik , Andergassen Sabine , Martius Georg , Lesanovsky Igor
Published: July 2022

Full information about a many-body quantum system is usually out-of-reach due to the exponential growth—with the size of the system—of the number of parameters needed to encode its state. Nonetheless, in order to understand the complex phenomenology that can be observed in these systems, it is often sufficient to consider dynamical or stationary properties of local observables or, at most, of few-body correlation functions. These quantities are typically studied by singling out a specific subsystem of interest and regarding the remainder of the many-body system as an effective bath. In the simplest scenario, the subsystem dynamics, which is in fact an open quantum dynamics, can be approximated through Markovian quantum master equations. Here, we formulate the problem of finding the generator of the subsystem dynamics as a variational problem, which we solve using the standard toolbox of machine learning for optimization. This dynamical or ‘Lindblad’ generator provides the relevant dynamical parameters for the subsystem of interest. Importantly, the algorithm we develop is constructed such that the learned generator implements a physically consistent open quantum time-evolution. We exploit this to learn the generator of the dynamics of a subsystem of a many-body system subject to a unitary quantum dynamics. We explore the capability of our method to recover the time-evolution of a two-body subsystem and exploit the physical consistency of the generator to make predictions on the stationary state of the subsystem dynamics.
Competition between collective and individual conical intersection dynamics in an optical cavity
Authors: Csehi András , Vendrell Oriol , Halász Gábor J , Vibók Ágnes
Published: July 2022

Light-induced nonadiabatic phenomena arise when molecules or molecular ensembles are exposed to resonant external electromagnetic fields. The latter can either be classical laser or quantized cavity radiation fields, which can couple to either the electronic, nuclear or rotational degrees of freedom of the molecule. In the case of quantized radiation fields, the light–matter coupling results in the formation of two new hybrid light–matter states, namely the upper and lower ‘polaritons’. Light-induced avoided crossings and light-induced conical intersections (CIs) between polaritons exist as a function of the vibrational and rotational coordinates of single molecules. For ensembles of N molecules, the N − 1 dark states between the two optically active polaritons feature, additionally, so-called collective CIs, involving the coordinates of more than one molecule to form. Here, we study the competition between intramolecular and collective light-induced nonadiabatic phenomena by comparing the escape rate from the Franck–Condon region of a single molecule and of a molecular ensemble coupled to a cavity mode. In situations where the polaritonic gap would be large and the dark-state decay channels could not be reached effectively, the presence of a seam of light-induced CI between the polaritons facilitates again the participation of the dark manifold, resulting in a cooperative effect that determines the overall non-radiative decay rate from the upper into the lower polaritonic states.
Local equilibrium properties of ultraslow diffusion in the Sinai model
Authors: Padash Amin , Aghion Erez , Schulz Alexander , Barkai Eli , Chechkin Aleksei V , Metzler Ralf , Kantz Holger
Published: July 2022

We perform numerical studies of a thermally driven, overdamped particle in a random quenched force field, known as the Sinai model. We compare the unbounded motion on an infinite 1-dimensional domain to the motion in bounded domains with reflecting boundaries and show that the unbounded motion is at every time close to the equilibrium state of a finite system of growing size. This is due to time scale separation: inside wells of the random potential, there is relatively fast equilibration, while the motion across major potential barriers is ultraslow. Quantities studied by us are the time dependent mean squared displacement, the time dependent mean energy of an ensemble of particles, and the time dependent entropy of the probability distribution. Using a very fast numerical algorithm, we can explore times up top 1017 steps and thereby also study finite-time crossover phenomena.
Evaluation of load-independent microhardness values in Plateau regions of Vanadium substituted Bi-2212 ceramics
Authors: Ulgen Asaf Tolga , Okur Semih , Erdem Umit , Pakdil Murat , Turgay Tahsin , Yildirim Gurcan
Published: July 2022

This study reveals extensively effect of homovalent V/Bi partial replacement in Bi2.0−xVxSr2.0Ca1.1Cu2.0Oy ceramic matrix (0.00 ≤ x ≤ 0.30) on the key mechanical design performance parameters and load-independent Vickers microhardness parameters in plateau limit region by means of experimental microhardness tests and semi-empiric approaching models. It is found that the vanadium substitution level of x = 0.01 is observed to be optimum amount in the Bi-2212 crystal lattice for refinement of fundamental mechanical properties due to the enhancement in stabilization of durable tetragonal phase, surface residual compressive stress and elastic recovery mechanism. Conversely, from the replacement level of x = 0.01 onwards, the lattice strain field and stress concentration sites enhance significantly depending on the increase of microscopic structural problems, interaction problems between adjacent layers and crack-initiating flaws in Bi-2212 ceramic system. Correspondingly, stress-induced phase transformation begins to play predominant role, and excess vanadium substituted ceramic materials are easily broken at relatively smaller test load. Moreover, the models indicate that every ceramic compound shows standard indentation size effect (ISE) feature due to predominant behavior of elastic recovery in crystal structure. Hence, presence of optimum vanadium ions strengthens typical ISE characteristic behavior. Furthermore, among semi-empirical models the indentation-induced cracking (IIC) model exhibits the highest performance to inspect real microhardness values of Bi2.0−xVxSr2.0Ca1.1Cu2.0Oy ceramic compounds in the plateau limit region.
A cosmological underdensity does not solve the Hubble tension
Authors: Castello Sveva , Högås Marcus , Mörtsell Edvard
Published: July 2022

A potential solution to the Hubble tension is the hypothesis
that the Milky Way is located near the center of a matter
underdensity. We model this scenario through the
Lemaître-Tolman-Bondi formalism with the inclusion of a
cosmological constant (ΛLTB) and consider a generalized
Gaussian parametrization for the matter density profile. We
constrain the underdensity and the background cosmology with a
combination of data sets: the Pantheon Sample of type Ia supernovae
(both the full catalogue and a redshift-binned version of it), a
collection of baryon acoustic oscillations data points and the
distance priors extracted from the latest Planck data
release. The analysis with the binned supernovae suggests a
preference for a -13 % density drop with a size of approximately
300 Mpc, interestingly matching the prediction for the so-called KBC
void already identified on the basis of independent analyses using
galaxy distributions. The constraints obtained with the full
Pantheon Sample are instead compatible with a homogeneous cosmology
and we interpret this radically different result as a cautionary
tale about the potential bias introduced by employing a binned
supernova data set. We quantify the level of improvement on the
Hubble tension by analyzing the constraints on the B-band absolute
magnitude of the supernovae, which provides the calibration for the
local measurements of H
0. Since no significant difference is
observed with respect to an analogous fit performed with a standard
ΛCDM cosmology, we conclude that the potential presence of a
local underdensity does not resolve the tension and does not
significantly degrade current supernova constraints on H
0.
Explaining the UHECR spectrum, composition and large-scale anisotropies with radio galaxies
Authors: Eichmann B. , Kachelrieß M. , Oikonomou F.
Published: July 2022

Radio galaxies are promising candidates as the sources of ultrahigh energy
cosmic rays (UHECRs). In this work, we examine if the stringent constraints
imposed by the dipole and quadropole anisotropies as well as the UHECR
spectrum and composition allow that radio galaxies are the dominant
extragalactic cosmic ray sources. In order to calculate the UHECR flux
emitted by individual
radio galaxies, we constrain their properties using information from the
radio-CR correlation and a dynamical evolution model. In
addition to the UHECR flux from individual, local sources, we
include the diffuse flux emitted by the bulk of non-local radio galaxies based
on their radio luminosity distribution. Analyzing the source parameters within
a range around their expected properties, we finally determine the
configurations of local sources describing well the UHECR spectrum, composition
and large-scale anisotropies. We obtain a good description of all data
even in the case that we include only a small number of local sources. In
particular, we find that scenarios where few sources like Fornax A and Virgo A
dominate the flux above the ankle, while low-luminosity radio galaxies
contribute an isotropic background dominating below the ankle,
provide a good fit to the data.
A Region Selection Method for Real-time Local Correlation Tracking of Solar Full-disk Magnetographs
Authors: Bai Yang , Lin Jia-Ben , Bai Xian-Yong , Yang Xiao , Wang Dong-Guang , Deng Yuan-Yong , Zhu Xiao-Ming , Hu Xing , Huang Wei , Tong Li-Yue
Published: July 2022

Hundreds of images with the same polarization state are first registered to compensate for the jitters during an observation and then integrated to realize the needed spatial resolution and sensitivity for solar magnetic field measurement. Due to the feature dependent properties of the correlation tracker technique, an effective method to select the feature region is critical for low-resolution full-disk solar filtergrams, especially those with less significant features when the Sun is quiet. In this paper, we propose a region extraction method based on a Hessian matrix and information entropy constraints for local correlation tracking (CT) to get linear displacement between different images. The method is composed of three steps: (1) extract feature points with the Hessian matrix, (2) select good feature points with scale spaces and thresholds, and (3) locate the feature region with the two-dimensional information entropy constraints. Both the simulated and observational experiments demonstrated that our region selection method can efficiently detect the linear displacement and improve the quality of a ground-based full-disk solar magnetogram. The local CT with the selected regions can obtain displacement detection results as good as the global CT and at the same time significantly reduce the average calculation time.
Effect of magnetic geometry on the energy partition between ions and electrons in the scrape-off layer of magnetic fusion devices
Authors: Li Y. , Xu G. , Dudson B. , Liu X. , Huang Z. , Killer C. , Feng Y. , Liu S. , Yan N. , Morales J. , Tsitrone E. , Brezinsek S. , Liang Y. , Eldon D. , Xiao C. , Geiger J. , Grulke O. , Otte M. , the WEST Team  , the W7-X Team
Published: July 2022

A universal energy partition mechanism between ions and electrons has been confirmed to exist in the scrape-off layer of both the WEST tokamak and the W7-X stellarator. A peaked plasma density structure induced by an infinite magnetic connection length structure is observed to destroy this dependence and enhance the local ion and electron temperature ratio in the stellarator. A theoretical analysis reveals that the ratio of ion and electron parallel heat conduction is predominant in determining this universality, while electrons would further be cooled in the density-peaked region.