bluuebunny/crossref_metadata_2025 huggingface dataset:
An off‐resonance insensitive orthogonal CSPAMM sequence (ORI‐O‐CSPAMM) for the acquisition of CSPAMM and MICSR grids in half scan time
Authors: Mella Hernán , Wang Hui , Montalba Cristian , Uribe Sergio
Published: July 2021

Purpose

To develop an Off‐Resonance Insensitive Orthogonal CSPAMM sequence (ORI‐O‐CSPAMM) for the acquisition of CSPAMM and MICSR grids in half of the acquisition time.

Methods

Phantom and mid‐level left ventricle short‐axis tagged images were acquired using CSPAMM, ORI‐CSPAMM, O‐CSPAMM, and the proposed ORI‐O‐CPAMM sequences to interrogate and compare its behavior under off‐resonance effects produced by vegetable oil and subcutaneous and epicardial fat. The images were compared in terms of signal and the capacity to obtain complex difference and MICSR images.

Results

Like ORI‐CSPAMM, the proposed ORI‐O‐CSPAMM sequence removed almost completely the off‐resonance artifacts produced during the tagging preparation. Tagging grids without DC components were obtained with ORI‐O‐CSPAMM using complex difference and MICSR from only two complementary images, which reduced the scan time to a half compared to CSPAMM and ORI‐CSPAMM. The removal of off‐resonance effects and the capacity to obtain MICSR images are advantages of ORI‐O‐CSPAMM over the O‐CSPAMM sequence.

Conclusion

We developed a novel and fast tagging sequence designed to remove off‐resonance effects during the tagging preparation, and to obtain complex difference and MICSR grids in half of the scan time compared to CSPAMM and ORI‐CSPAMM sequences, which could allow its application to clinical protocols.
Complementary time‐frequency domain networks for dynamic parallel MR image reconstruction
Authors: Qin Chen , Duan Jinming , Hammernik Kerstin , Schlemper Jo , Küstner Thomas , Botnar René , Prieto Claudia , Price Anthony N. , Hajnal Joseph V. , Rueckert Daniel
Published: July 2021

Purpose

To introduce a novel deep learning‐based approach for fast and high‐quality dynamic multicoil MR reconstruction by learning a complementary time‐frequency domain network that exploits spatiotemporal correlations simultaneously from complementary domains.

Theory and Methods

Dynamic parallel MR image reconstruction is formulated as a multivariable minimization problem, where the data are regularized in combined temporal Fourier and spatial (x‐f) domain as well as in spatiotemporal image (x‐t) domain. An iterative algorithm based on variable splitting technique is derived, which alternates among signal de‐aliasing steps in x‐f and x‐t spaces, a closed‐form point‐wise data consistency step and a weighted coupling step. The iterative model is embedded into a deep recurrent neural network which learns to recover the image via exploiting spatiotemporal redundancies in complementary domains.

Results

Experiments were performed on two datasets of highly undersampled multicoil short‐axis cardiac cine MRI scans. Results demonstrate that our proposed method outperforms the current state‐of‐the‐art approaches both quantitatively and qualitatively. The proposed model can also generalize well to data acquired from a different scanner and data with pathologies that were not seen in the training set.

Conclusion

The work shows the benefit of reconstructing dynamic parallel MRI in complementary time‐frequency domains with deep neural networks. The method can effectively and robustly reconstruct high‐quality images from highly undersampled dynamic multicoil data ( and yielding 15 s and 10 s scan times respectively) with fast reconstruction speed (2.8 seconds). This could potentially facilitate achieving fast single‐breath‐hold clinical 2D cardiac cine imaging.
Reloading in barodesy employing the asymptotic state boundary surface
Authors: Bode Manuel , Fellin Wolfgang , Medicus Gertraud
Published: July 2021

The reloading behaviour of the soil is dominated by effects of the recent deformation history as well as by the overall stress history, indicated by overconsolidation. The stiffness of an overconsolidated soil is higher than the stiffness of normally consolidated soil. In basic hypoplastic and barodetic models, the stiffness for reloading is underestimated, and thus so‐called ratcheting effects appear. In this article, we propose a relation to improve the reloading behaviour of barodesy: we introduce an extension, which increases the stiffness in dependence of the distance to the asymptotic state boundary surface and the current dilatancy. Thus, within an intermediate strain range, the stress‐strain behaviour is improved and ratcheting effects are significantly reduced. The behaviour of the proposed extension is verified by simulation of typical element tests and validated by a comparison with experimental results.
Robust tensor train component analysis
Authors: Zhang Xiongjun , Ng Michael K.
Published: July 2021

Robust Principal Component Analysis plays a key role in various fields such as image and video processing, data mining, and hyperspectral data analysis. In this paper, we study the problem of robust tensor train (TT) principal component analysis from partial observations, which aims to decompose a given tensor into the low TT rank and sparse components. The decomposition of the proposed model is used to find the hidden factors and help alleviate the curse of dimensionality via a set of connected low‐rank tensors. A relaxation model is to minimize a weighted combination of the sum of nuclear norms of unfolding matrices of core tensors and the tensor norm. A proximal alternating direction method of multipliers is developed to solve the resulting model. Furthermore, we show that any cluster point of the convergent subsequence is a Karush‐Kuhn‐Tucker point of the proposed model under some conditions. Extensive numerical examples on both synthetic data and real‐world datasets are presented to demonstrate the effectiveness of the proposed approach.
A total‐Lagrangian material point method for coupled growth and massive deformation of incompressible soft materials
Authors: Zhang Zijian , Pan Yunxiang , Wang Jianhua , Zhang Hongwu , Chen Zhen , Zheng Yonggang , Ye Hongfei
Published: July 2021

A total‐Lagrangian material point method (TLMPM) with a mixed formulation is proposed in this article for the mechanical analysis of incompressible soft materials coupling the mass growth and massive deformation. In this work, the growth‐induced large deformation behavior is handled within the framework of the material point method (MPM) based on the multiplicative decomposition of deformation gradient. To overcome the volumetric locking caused by the incompressibility of soft materials, a weak‐form equation for hydrostatic pressure is implemented into a mixed MPM framework. To deal with the massive deformation caused by growth, the total‐Lagrangian formulation is further introduced into the mixed MPM. The TLMPM discretized via the B‐spline basis functions is then developed in the proposed solution procedure. The efficiency and accuracy of the proposed method are demonstrated by several representative two‐ and three‐dimensional numerical examples with large deformation such as the free growth of blocks and constrained growth of rings. The challenging problems including the volumetric growth of bilayers with complex geometry and the strain‐driven growth of skin are further investigated using the proposed TLMPM to illustrate its ability for evaluating the growth phenomena and behaviors as observed in nature and engineering.
A scoping review of alternative methods of delivering ethics education in nursing
Authors: Tanaka Maki , Tezuka Sonoe
Published: July 2021

Aim

We conducted a scoping review of nursing ethics education to examine educational formats that go beyond traditional lectures.

Design

This study was a scoping review.

Methods

We used seven databases and relevant search terms, including nursing ethics, morals, values, nursing students and nursing ethics education.

Results

Of 5,190 papers, 14 quasi‐experimental studies met the inclusion criteria. All papers examined practices and self‐study added to traditional lecture styles (i.e. the control group). Five practices emerged as follows: combined web (i.e. Internet) and lecture, web‐based self‐study, simulation, group learning and analysing ethical issues. The purpose, method and evaluation method differed based on the country in which the study was conducted. These educational interventions yielded significant differences in knowledge and in nursing students' critical thinking and ethical sensitivity postintervention. Multi‐faceted ethics education will lay the foundation for effective practical training and practice.
Indonesian president's transformational leadership in the critical era
Authors: Asmawi M. Rosul , Fulazzaky Mohamad Ali
Published: July 2021

Leadership research tends to focus on the importance of transformational leadership in normal times; there have been few studies to date on transformational leadership in a crisis. Leadership effectiveness was identified as the most important mechanism, particularly in times of crisis. This paper aims to reflect on the President of Indonesia's crisis leadership model in order to generate transformative leadership characteristics to deal with the situation. This study showed that Indonesian presidents generally exhibit strong idealized influence and inspirational motivation, but they were often weak in intellectual stimulation and individualized consideration. What is currently needed by Indonesia in facing a crisis is a transformative leader who always strives to advance the nation and avoiding to prioritize their group for the sake of national unity and sovereignty, understands the problems faced by their subordinates, motivates them to seek new approaches in performing their duties, organizational tasks, listens attentively to input from subordinates, and especially willing to pay attention to the needs of subordinates. During a crisis, transformational leadership is necessarily required to manage the economy, politics, and society in Indonesia. This study compared transformative leadership from previous presidents towards the present president, Joko Widodo, through literature studies and examined the presence of leadership style for each president. Five indicators of successful transformative leadership must be accomplished, including strives to advance the nation and avoiding to prioritize their group for the sake of national unity and sovereignty, understands the problems faced by their subordinates, motivates them to seek new approaches in performing their duties, organizational tasks, listens attentively to input from subordinates, and especially willing to pay attention to the needs of subordinates.
Pingo drilling reveals sodium–chloride‐dominated massive ice in Grøndalen, Spitsbergen
Authors: Demidov Vasiliy , Wetterich Sebastian , Demidov Nikita , Schirrmeister Lutz , Verkulich Sergey , Koshurnikov Andrey , Gagarin Vladimir , Ekaykin Aleksey , Terekchov Anton , Veres Arina , Kozachek Anna
Published: July 2021

Drilling of a 21.8‐m‐deep borehole on top of the 10.5‐m‐high Nori pingo that stands at 32 m asl in Grøndalen Valley (Spitsbergen) revealed a 16.1‐m‐thick massive ice enclosed by frozen sediments. The hydrochemical compositions of both the massive ice and the sediment extract show a prevalence of Na+ and Cl− ions throughout the core. The upper part of the massive ice (stage A) has low mineralization and shows an isotopically closed‐system trend in δ18O and δD isotopes decreasing down‐core. Stage B exhibits high mineralization and an isotopically semi‐open system. The crystallographic structure of Nori pingo’s massive ice provides evidence of several large groundwater intrusions that support the defined formation stages. Analysis of local aquifers leads to suggest that the pingo was hydraulically sourced through a local fault zone by low mineralized sodium–bicarbonate groundwater of a Paleogene strata aquifer. This groundwater was enriched by sodium and chloride ions while filtering through marine valley sediments with residual salinity. The comparison between the sodium–chloride‐dominated massive ice of the Nori pingo and the sodium–bicarbonate‐dominated ice of the adjacent Fili pingo that stands higher up the valley may serve as an indicator for groundwater source patterns of other Nordenskiöld Land pingos.
Real‐world evidence with The Rezūm System: A retrospective study and comparative analysis on the efficacy and safety of 12 month outcomes across a broad range of prostate volumes
Authors: Ines Matthew , Babar Mustufa , Singh Sandeep , Iqbal Nazifa , Ciatto Michael
Published: July 2021

Background

To provide 12‐month unbiased outcomes with The Rezūm System (Rezūm), a convective water vapor thermal therapy for patients with lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). Results from this retrospective, real‐world evidence (RWE) study were compared to those of previous studies with the aim to evaluate the device's safety and efficacy in a real‐world patient population.

Methods

Patients 45 years or older with an International Prostate Symptom Score (IPSS) score ≥8, prostate volume (PV) between 20cc and 120cc, who were 12 months posttreatment, and had at least one follow‐up were included. Patients were broken into groups based on baseline PV; 30–80cc, <30cc, and >80cc. IPSS, PV, quality of life (QoL), maximum urinary flow rate (Qmax), adverse events (AE), postvoid residual, prostate‐specific antigen, BPH medication usage, and International Index of Erectile Function were collected and analyzed at baseline, 1, 3, 6, and/or 12 months.

Results

A total of 179 patients were included in a retrospective study. IPSS, QoL, and Qmax significantly improved at follow‐up time points (p < .05). There were no significant differences at 12 months in IPSS and QoL point reduction or Qmax improvement between the previous studies and any of the RWE groups. BPH medication reduction was seen at 3 months and remained durable up to 12 months. When compared to previous studies, the RWE study had similar rates of urinary retention, urinary tract infection, and dysuria but significantly higher rates of hematuria for the 30–80cc (71.7%), <30cc (58.8%), and >80cc (80.0%) groups (p < .001).

Conclusions

The RWE study shows rapid and durable relief in LUTS, consistent with that observed in literature. Although Rezūm had a reasonably acceptable AEs profile, patients should be counseled preoperatively for AEs. As a first line therapy, Rezūm is an attractive option for men with BPH irrespective of their prostate size.
Development and validation of a predictive model for determining clinically significant prostate cancer in men with negative magnetic resonance imaging after transrectal ultrasound‐guided prostate biopsy
Authors: Liu Gang , Zhu Yuze , Yao Zichuan , Jiang Yunzhong , Wu Bin , Bai Song
Published: July 2021

Background

The interpretation of negative magnetic resonance imaging (MRI) screening results for clinically significant prostate cancer (csPCa) (International Society of Urological Pathology grade ≥group 2) is debatable and poses a clinical dilemma for urologists. No nomograms have been developed to predict csPCa in such populations. In this study, we aimed to develop and validate a model for predicting the probability of csPCa in men with negative MRI (PI‐RADS score 1–2) results after transrectal ultrasound‐guided systematic prostate biopsy.

Methods

The development cohort consisted of 728 patients with negative MRI results who underwent subsequent prostate biopsy at our center between January 1, 2014 and December 31, 2017. The patients' clinicopathologic data were recorded. The Lasso regression was used for data dimension reduction and feature selection, then multivariable binary logistic regression was used to build a predictive model with regression coefficients. The model was validated in an independent cohort of 334 consecutive patients from January 1, 2018 and June 30, 2020. The performance of the predictive model was assessed with respect to discrimination, calibration, and decision curve analysis.

Results

The predictors incorporated in this model included age, history of previous negative prostate biopsy, prostate specific antigen density (PSAD), and lower urinary tract symptoms, with PSAD being the strongest predictor. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.875 (95% confidence interval, 0.816–0.933) and good calibration (unreliability test, p = .540). Decision curve analysis demonstrated that the model was clinically useful.

Conclusion

This study presents a good nomogram that can aid pre‐biopsy risk stratification for the detection of csPCa, and that may help inform biopsy decisions in patients with negative MRI results.
Urban sustainability and the subjective well‐being of migrants: The role of risks, place attachment, and aspirations
Authors: Szaboova Lucy , Safra de Campos Ricardo , Adger W. Neil , Abu Mumuni , Codjoe Samuel Nii Ardey , Franco Gavonel Maria , Das Shouvik , Siddiqui Tasneem , Rocky Mahmudol Hassan , Hazra Sugata
Published: July 2021

While material conditions of migrant populations on average tend to improve over time as they become established in new destinations, individual trajectories of material and subjective well‐being often diverge. Here, we analyse how social and environmental factors in the urban environment shape the subjective well‐being of migrant populations. We hypothesise these factors to include (a) perceived social and environmental risk, (b) attachment to place, and (c) migrant aspirations. We analyse data from a cross‐sectional survey of 2641 individual migrants in seven cities across Ghana, India, and Bangladesh. The results show that the persistence of inferior material conditions, exposure to environmental hazards, and constrained access to services and employment affect migrants' subjective well‐being. Hence, social and environmental risks constitute urban precarity for migrants whose social vulnerability persist in their destination. Meeting migration‐related aspirations and developing an affinity to urban destinations have the potential to mitigate negative sentiments from perceived risks. These findings have implications for future urban planning and sustainability.
Metal−Insulator Transition in Strained Graphene: A Quantum Monte Carlo Study
Authors: Zhang Lufeng , Ma Chi , Ma Tianxing
Published: July 2021

Motivated by the possibility of a strain tuning effect on electronic properties of graphene, the semimetal−Mott insulator transition process on the uniaxial honeycomb lattice is numerically studied using the determinant quantum Monte Carlo method. As the simulations are based on the half‐filled‐repulsive Hubbard model, the system is sign‐problem free. Herein, the temperature‐dependent DC conductivity to characterize electronic transport properties is used. The data suggest that metal is suppressed in the presence of strain. More interestingly, within the finite‐size‐scaling study, a novel antiferromagnetic phase arises at around . Therefore, a phase diagram generated by the competition between interactions, and strain is established, which may help to expand the application of strain effect on graphene.
Bacosides from Bacopa monnieri extract: An overview of the effects on neurological disorders
Authors: Banerjee Samarpita , Anand Uttpal , Ghosh Suchhanda , Ray Durga , Ray Puja , Nandy Samapika , Deshmukh Ganpat Dewaji , Tripathi Vijay , Dey Abhijit
Published: July 2021

From ancient history, complementary and alternative medicines have played a significant role as holistic therapeutic treatments of various human diseases including cancer, diabetes, neurological diseases, and skin problems. One Indian medicinal plant (herb), Bacopa monnieri has been used in many parts of the world as such medicine, particularly for the treatment of various neurological disorders. It is well known as a potent “tonic for the human brain,” which serves as a memory enhancer. Multiple studies proved that this herb contains a plethora of potential bioactive, phytochemical compounds with synergistic properties. The main purpose of the present review is to shed light on the use of Bacopa monnieri and its active principles (bacosides) in the management of neurological disorders. Furthermore, the signaling pathways modulated by bacosides have been critically discussed in this review. Moreover, we have critically summarized the present knowledge of this perennial creeping herb based upon the literature mining from different scientific engines.
Towards development of a tele‐mentoring framework for minimally invasive surgeries
Authors: Shabir Dehlela , Abdurahiman Nihal , Padhan Jhasketan , Trinh May , Balakrishnan Shidin , Kurer Mohamed , Ali Omar , Al‐Ansari Abdulla , Yaacoub Elias , Deng Zhigang , Erbad Aiman , Mohammed Amr , Navkar Nikhil V.
Published: July 2021

Background

Tele‐mentoring facilitates the transfer of surgical knowledge. The objective of this work is to develop a tele‐mentoring framework that enables a specialist surgeon to mentor an operating surgeon by transferring information in a form of surgical instruments' motion required during a minimally invasive surgery.

Method

A tele‐mentoring framework is developed to transfer video stream of the surgical field, poses of the scope and port placement from the operating room to a remote location. From the remote location, the motion of virtual surgical instruments augmented onto the surgical field is sent to the operating room.

Results

The proposed framework is suitable to be integrated with laparoscopic as well as robotic surgeries. It takes on average 1.56 s to send information from the operating room to the remote location and 0.089 s for vice versa over a local area network.

Conclusions

The work demonstrates a tele‐mentoring framework that enables a specialist surgeon to mentor an operating surgeon during a minimally invasive surgery.
Consequences of COVID‐19 pandemic on solid waste management: Scenarios pertaining to developing countries
Authors: Almulhim Abdulaziz I. , Ahmad Imran , Sarkar Silpi , Chavali Murthy
Published: July 2021

Undoubtedly the most searched and spoken word of last year is coronavirus disease 2019 (COVID‐19), which initially originated in Wuhan, China near the end of 2019. COVID‐19 is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Albeit almost all countries shut down their borders to prevent rapid spread of the virus. However, the number of cases continues to increase in developing countries at a faster rate due to community and cluster transmission. The severity of this epidemic made it a pandemic as it progressed to over 200 countries. The World Health Organization (WHO), governments, and national disease control and prevention units worked together to break the chain and are working to contain the catastrophic impact of COVID‐19. They formulated and recommended various guidelines like social distancing, frequent hand washing, and social distancing to inhibit the spread of the virus. WHO also advised that the general population and medical personnel wear face masks, face shields, gloves, and aprons. As a result, this waste category has substantially increased and, if not disposed of properly, may cause the infection or help to catalyze COVID‐19. In developing countries, poor solid waste management may aggravate chances of spreading COVID‐19. Sustainable solid waste management is a critical parameter for the health, wellbeing, and development of society. The measures adopted to contain and restrict the spread of the COVID‐19 pandemic and minimize the degrees of freedom in commercial events affected solid waste management considerably. During this crucial time, the services provided by waste management agencies and personnel are invaluable and these services help to prevent the improper disposal of waste, which may lead to health risks due to the spread of COVID. COVID‐19 is a new and novel virus and experts are learning more about it overtime and with evolving science. This review paper provides insight into different types of solid wastes generated during the pandemic, their consequences, and the implication of various policies.
Adaptive iterative learning control for discrete‐time nonlinear systems with multiple iteration‐varying high‐order internal models
Authors: Yu Miao , Chai Sheng
Published: July 2021

In this work, an adaptive iterative learning control (AILC) method is designed for a class of parametric discrete‐time nonlinear systems with random initial condition, unknown time‐varying input gain and multiple time‐iteration‐varying factors including multiple unknown time‐iteration‐varying parameters and unknown time‐iteration‐varying external disturbance. The iteration‐varying factors can be generated by virtue of multiple iteration‐varying high‐order internal models, respectively, where iteration‐varying high‐order internal model means it has iteration‐varying order or coefficients. Moreover, the parameter updating law is designed based on the recursive least squares algorithm. Using the designed AILC based on iteration‐varying high‐order internal model, the learning convergence in the iteration domain is guaranteed through rigorous theoretical analysis under Lyapunov theory. Finally, two simulation examples are given to demonstrate that the proposed scheme is effective.
Unveiling Crystal Orientation in Quasi‐2D Perovskite Films by In Situ GIWAXS for High‐Performance Photovoltaics
Authors: Liang Dong , Dong Chong , Cai Lei , Su Zhenhuang , Zang Jiaqing , Wang Chenyue , Wang Xuechun , Zou Yatao , Li Yajuan , Chen Li , Zhang Liujiang , Hong Zhiwei , El‐Shaer Abdelhamid , Wang Zhao‐Kui , Gao Xingyu , Sun Baoquan
Published: July 2021

Quasi‐2D perovskites are enchanting alternative materials for solar cells due to their intrinsic stability. The manipulation of crystal orientation of quasi‐2D perovskites is indispensable to target efficient devices, however, the origin of orientation during the film fabrication process still lacks in‐depth understanding and convincing evidence yet, which hinders further boosting the performance of photovoltaic devices. Herein, the crystallizing processes during spin‐coating and annealing are probed by in situ grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), and the incident‐angle‐dependent GIWAXS is conducted to unveil the phase distribution in the films. It is found that undesirable lead iodide sol–gel formed intermediate phase would disturb oriented crystalline growth, resulting in random crystal orientation in poor quasi‐2D films. A general strategy is developed via simple additive agent incorporation to suppress the formation of the intermediate phase. Accordingly, highly oriented perovskite films with reduced trap density and higher carrier mobility are obtained, which enables the demonstration of optimized quasi‐2D perovskite solar cells with a power conversion efficiency of 15.2% as well as improved stability. This work paves a promising way to manipulate the quasi‐2D perovskites nucleation and crystallization processes via tuning nucleation stage.
Inner Encapsulating Approach for Moisture‐Stable Perovskite Solar Cells
Authors: Kim Yong Ryun , Kim Juae , Kim Heejoo , Yoon Chang-Jae , Yun Jun-Tae , Kim Ju-Hyeon , Gu Ayeong , Suh Hongsuk , Lee Kwanghee
Published: July 2021

The degradation of the perovskite layer in atmospheric air is a critical bottleneck for the commercialization of perovskite solar cells (PSCs). As the moisture and oxygen in air penetrate the charge transport layer/top metal electrode interface, both adjacent layers and perovskite layers decompose in the PSCs. Herein, moisture‐stable inverted PSCs (I‐PSCs) based on methylammonium lead triiodide (MAPbI3) by introducing amine‐functionalized small molecules as metal adhesive layers (MALs) between the electron transport layer (ETL) and metal electrode (here, Cu) are demonstrated. A strong coordination bond of CuN forms at the Cu/MAL interface, leading to the layer–layer growth mode for the dense formation of Cu electrodes with a strong adhesion to the ETL. Thus, this modified electrode prevents the ingress of moisture into the I‐PSCs, resulting in outstanding moisture stability; the efficiency of I‐PSCs retains 90% of the initial efficiency after 200 days of exposure to atmospheric air (25 °C, relative humidity [RH] ≈20–40%). Under harsher conditions (e.g., 25 °C/RH65%, 25 °C/RH85% and immersion in water) for a considerable time period, the modified I‐PSCs manifest relatively no degradation compared with the pristine I‐PSCs. It is believed that this breakthrough provides a significant impact on improving the stability of I‐PSCs.
High‐Temperature Perovskite Solar Cells
Authors: Dong Zijing , Li Weiping , Wang Hailiang , Jiang Xiaoyu , Liu Huicong , Zhu Liqun , Chen Haining
Published: July 2021

Herein, high‐temperature (over 200 °C) perovskite solar cells (PSCs) are fabricated and studied for the first time. Inorganic CsPbI2Br perovskite is used as absorber and carbon nanotubes (CNTs) are directly used as the hole extraction electrode. Such device retains over 80% of its initial power conversion efficiency (PCE) after heating at 200 °C for 45 h, enabling its operation at high temperatures. By recording reverse and forward J–V curves at different temperatures (25–220 °C), temperature coefficients of photovoltaic parameters are obtained. Compared with conventional high‐temperature solar cells (Si, CuInGaSe, and GaAs), CsPbI2Br devices show superior VOC and FF temperature coefficients but inferior JSC temperature coefficients. As a result, PCE temperature coefficients of CsPbI2Br devices are superior over Si and CuInGaSe solar cells, and are comparable with those of GaAs solar cells. Meanwhile, the mitigation of charge accumulation at elevated temperatures results in a gradual decrease in J–V hysteresis. Therefore, this study may expand the application of PSCs into high‐temperature fields, such as space exploration.
Effects of stiffeners on the capacities of cold‐formed steel channel members
Authors: Pham Ngoc Hieu , Vu Quoc Anh
Published: July 2021

This paper investigates the effects of stiffeners on the compressive and flexural capacities of cold‐formed steel channel members. Stiffeners are added on the web of the channel section to form a new section called SupaCee. This new section is shown to be more innovative and stable than the traditional channel section. The structural advantages of this new section are investigated by comparing the capacities of SupaCee and channel members under compression and bending. The capacities are determined by using the direct strength method (DSM) according to AS/NZS 4600:2018 with the support of THIN‐WALL‐2, a buckling analysis program. It was found that the stiffeners are effective for small section dimensions and thicknesses, but become ineffective for large section dimensions.
Contagious bovine pleuropneumonia: Seroprevalence and its associated risk factors in selected districts of Afar region, Ethiopia
Authors: Negash Wossene , Dubie Teshager
Published: July 2021

Background

In pastoral and lowland areas of the country particularly in Afar region, studies suggested higher prevalence of contagious bovine pleuropneumonia (CBPP) than mid and highland agro‐ecologies. Though CBPP is a prime constraint to cattle productivity in the region, research outputs pertaining to CBPP are unavailable compared to highland areas. Thus, the objectives of the current study were to determine seroprevalence of CBPP and assess risk factors in selected districts of Afar region.

Methods

A cross‐sectional study was conducted on cattle aged 6 months and above from February 2018 to January 2019 in selected districts of the region. A total of 420 blood samples were collected and sera were separated for further serologic analysis. Using competitive enzyme linked immunosorbent assay (c‐ELISA), antibodies against Mycoplasma mycoides subspecies mycoides small colony (MmmSc) were detected at National Veterinary Institute, Ethiopia. Data were analysed using Stata version 14.0.

Result

Of 420 samples tested by c‐ELISA, 158 samples were found to be positive for CBPP providing an overall seroprevalence of 37.6%. Among the three risk factors considered (age, sex and district) assessed, only two (age and district) were found to be associated significantly with the disease (p < 0.05) at 95% CI and p‐value less than 5% applying logistic regression.

Conclusion

The study has revealed a higher prevalence of CBPP over the study areas urging a coordinated act to be set in place.
Rare atrioventricular septal defects in veterinary species: Complete atrioventricular septal defect in a dog and double‐outlet right atrium in a cat
Authors: Saunders Rebecca S.
Published: July 2021

Case 1: A 9‐year‐old Yorkshire terrier mix was referred for evaluation of heart failure presumed to be secondary to myxomatous mitral valve disease. Case 2: A 6‐year‐old Domestic Longhair cat was referred for evaluation of heart failure presumed to be secondary to hypertrophic cardiomyopathy. Thoracic radiographs revealed pulmonary overcirculation suggestive of a cardiac shunt in both cases. Echocardiographic findings confirmed the diagnosis of rare atrioventricular septal defects (AVSDs): complete AVSD (case 1) and double‐outlet right atrium (case 2). Complete AVSDs are rare congenital cardiac defects in veterinary species that result from inappropriate embryogenesis of the atrioventricular septum. Sequelae include congestive heart failure and possibly shunt reversal due to concomitant pulmonary hypertension. Few veterinary reports describe the natural timeline of this condition and outcomes. This report describes both a dog and cat that presented symptomatic in adulthood, were diagnosed via echocardiography and medically managed long‐term.
Restricted active space configuration interaction methods for strong correlation: Recent developments
Authors: Casanova David
Published: July 2021

In this review we outline the theory and recent progress of the restricted active space configuration interaction (RASCI) methodology within the hole and particle approximation. The RASCI is a single reference approach based on the splitting of the orbital space in different subsets, in which the target CI space is expressed by the concomitant number of electrons and empty orbitals in each subspace. Initially, the method was born as a spin complete version of the spin‐flip ansatz able to deal with any number of unpaired electrons. Since then, the method has experienced several improvements related to its theoretical foundations, its efficient implementation, in the characterization of RASCI wave functions, and in the calculation of molecular properties. It has shown to be especially suitable for the characterization of medium to large molecular diradicals and polyradicals, and to the study of photophysical processes involving open‐shell species and/or multiexcitonic states, like in the singlet fission reaction. But, despite this success, several limitations emerge from the sever truncation of the excitation operator, which might translate into inaccurate relative energies between different regions of the potential energy surface, and overestimated (or underestimated) excitation energies. These errors are associated with the lack of dynamic correlation, which has motivated the development and implementation of various improvements based on multi‐reference perturbation theory and to blend the RASCI wave function with density functional theory through range separation of electron–electron interactions. Finally, we discuss some of the properties available from RASCI wave functions and give potential future developments.

This article is categorized under:

Electronic Structure Theory > Ab Initio Electronic Structure Methods

Software > Quantum Chemistry

Quantum Computing > Theory Development
Duality of positive and negative integrable hierarchies via relativistically invariant fields
Authors: Lou S. Y. , Hu X. B. , Liu Q. P.
Published: July 2021

Abstract

It is shown that the relativistic invariance plays a key role in the study of integrable systems. Using the relativistically invariant sine-Gordon equation, the Tzitzeica equation, the Toda fields and the second heavenly equation as dual relations, some continuous and discrete integrable positive hierarchies such as the potential modified Korteweg-de Vries hierarchy, the potential Fordy-Gibbons hierarchies, the potential dispersionless Kadomtsev-Petviashvili-like (dKPL) hierarchy, the differential-difference dKPL hierarchy and the second heavenly hierarchies are converted to the integrable negative hierarchies including the sG hierarchy and the Tzitzeica hierarchy, the two-dimensional dispersionless Toda hierarchy, the two-dimensional Toda hierarchies and negative heavenly hierarchy. In (1+1)-dimensional cases the positive/negative hierarchy dualities are guaranteed by the dualities between the recursion operators and their inverses. In (2+1)-dimensional cases, the positive/negative hierarchy dualities are explicitly shown by using the formal series symmetry approach, the mastersymmetry method and the relativistic invariance of the duality relations. For the 4-dimensional heavenly system, the duality problem is studied firstly by formal series symmetry approach. Two elegant commuting recursion operators of the heavenly equation appear naturally from the formal series symmetry approach so that the duality problem can also be studied by means of the recursion operators.
Leading logs in QCD axion effective field theory
Authors: Alonso-Álvarez Gonzalo , Ertas Fatih , Jaeckel Joerg , Kahlhoefer Felix , Thormaehlen Lennert J.
Published: July 2021

Abstract

The axion is much lighter than all other degrees of freedom introduced by the Peccei-Quinn mechanism to solve the strong CP problem. It is therefore natural to use an effective field theory (EFT) to describe its interactions. Loop processes calculated in the EFT may however explicitly depend on the ultraviolet cutoff. In general, the UV cutoff is not uniquely defined, but the dimensionful couplings suggest to identify it with the Peccei-Quinn symmetry-breaking scale. An example are K+ → π+ + a decays that will soon be tested to improved precision in NA62 and KOTO and whose amplitude is dominated by the term logarithmically dependent on the cutoff. In this paper, we critically examine the adequacy of using such a naive EFT approach to study loop processes by comparing EFT calculations with ones performed in complete QCD axion models. In DFSZ models, for example, the cutoff is found to be set by additional Higgs degrees of freedom and to therefore be much closer to the electroweak scale than to the Peccei-Quinn scale. In fact, there are non-trivial requirements on axion models where the cutoff scale of loop processes is close to the Peccei-Quinn scale, such that the naive EFT result is reproduced. This suggests that the existence of a suitable UV embedding may impose restrictions on axion EFTs. We provide an explicit construction of a model with suitable fermion couplings and find promising prospects for NA62 and IAXO.
Charge-Swapping Q-balls and Their Lifetimes
Authors: Xie Qi-Xin , Saffin Paul M. , Zhou Shuang-Yong
Published: July 2021

Abstract

For scalar theories accommodating spherically symmetric Q-balls, there are also towers of quasi-stable composite Q-balls, called charge swapping Q-balls (CSQs). We investigate the properties, particularly the lifetimes, of these long-lived CSQs in 2+1D and 3+1D using numerical simulations with efficient second order absorbing boundary conditions. We find that the evolution of a CSQ typically consists of 4 distinct stages: initial relaxation, first plateau (CSQ stage), fast decay and second plateau (oscillon stage). We chart the lifetimes of CSQs for different parameters of the initial conditions and of the potential, and show the attractor behavior and other properties of the CSQs.
Driven black holes: from Kolmogorov scaling to turbulent wakes
Authors: Andrade Tomas , Pantelidou Christiana , Sonner Julian , Withers Benjamin
Published: July 2021

Abstract

General relativity governs the nonlinear dynamics of spacetime, including black holes and their event horizons. We demonstrate that forced black hole horizons exhibit statistically steady turbulent spacetime dynamics consistent with Kolmogorov’s theory of 1941. As a proof of principle we focus on black holes in asymptotically anti-de Sitter spacetimes in a large number of dimensions, where greater analytic control is gained. We focus on cases where the effective horizon dynamics is restricted to 2+1 dimensions. We also demonstrate that tidal deformations of the horizon induce turbulent dynamics. When set in motion relative to the horizon a deformation develops a turbulent spacetime wake, indicating that turbulent spacetime dynamics may play a role in binary mergers and other strong-field phenomena.
Supersymmetric graphene on squashed hemisphere
Authors: Gupta Rajesh Kumar , Ray Augniva , Sil Karunava
Published: July 2021

Abstract

We compute the partition function of $$ \mathcal{N} $$
N
= 2 supersymmetric mixed dimensional QED on a squashed hemisphere using localization. Mixed dimensional QED is an abelian gauge theory coupled to charged matter fields at the boundary. The partition function is a function of the complex gauge coupling τ, the choice of R-symmetry and the squashing deformation. The superconformal R-symmetry is determined using the 3-dimensional F-maximization. The free energy as a function of squashing deformation allows computing correlation functions that contain the insertion of the energy-momentum tensor. We compute the 2-point correlation function of the energy-momentum tensor of 3-dimensional theory by differentiating the free energy with respect to the squashing parameter. We comment on the behaviour of the 2-point function as we change the complex coupling τ.
Floating norms for individualising the ANB angle and the WITS appraisal in orthodontic cephalometric analysis based on guiding variables
Authors: Paddenberg Eva , Proff Peter , Kirschneck Christian
Published: July 2021

Purpose

The sagittal skeletal relationship of maxilla and mandible (skeletal class) can generally be determined via lateral cephalograms (ANB angle or Wits appraisal) by comparing measurements to empirical norms based on the respective population mean. However, values differing from these empirical norms also enable a therapeutically desired, normal class I occlusion depending on individual craniofacial pattern, thus requiring floating norms based on guiding variables. As available regression equations consider only few predictor variables and are not up-to-date regarding a contemporary patient collective, the aim of this study was to establish improved and extended regression equations for individualising the ANB angle and Wits appraisal.

Methods

This retrospective, cross-sectional multicentre study was based on 71 Caucasian male and female subjects of any age with normal dental occlusion. We cephalometrically analysed digitised pretreatment lateral radiographs and performed multiple linear regression analyses to identify suitable skeletal predictor variables for individualising the ANB angle and Wits appraisal.

Results

Inter- and intrarater reliability tests showed mostly perfect measurement concordance. Both original regression equations by Panagiotidis/Witt and Järvinen could be updated for a contemporary population with new regression coefficients. The equation for individualising the ANB could be further optimised in its prediction reliability by adding the skeletal predictor variables NL-NSL, NSBa, facial axis (Ricketts) and index (Hasund), whereas the recalculated Wits equation could not be further improved by additional guiding variables.

Conclusions

The improved regression formulae for individualising the ANB angle and Wits appraisal should help to improve the assessment of sagittal skeletal class in clinical orthodontic practice.
12 × 6 Gy stereotactic radiotherapy for lung tumors. Is there a difference in response between lung metastases and primary bronchial carcinoma?
Authors: Lubgan Dorota , Semrau Sabine , Lambrecht Ulrike , Gaipl Udo S. , Fietkau Rainer
Published: July 2021

Purpose

The aim of this study was to evaluate the safety and long-term tumor control after stereotactic radiotherapy (SRT) with 12 × 6 Gy of patients with primary bronchial carcinoma (BC) or with pulmonary metastases (MET) of various solid tumors. Local progression-free survival (LPFS), progression-free survival (PFS), overall survival (OS), and prognostic factors were compared.

Methods

Between May 2012 and January 2020, 168 patients with 206 pulmonary lesions (170 MET and 36 primary BC) were treated with 12 × 6 Gy (BED10116 Gy). The irradiated pulmonary MET were from the following cancers: 47 (27.6%) head and neck, 37 (21.8%) rectum or colon, 30 (17.6%) bronchial, 13 (7.6%) malignant melanoma, 9 (5.3%) esophageal, 9 (5.3%) sarcoma, and 25 (14.8%) other.

Results

The median follow-up was 16.26 months (range: 0.46–89.34) for BC and 19.18 months (0.89–91.11) for MET. Survival rates at 3 years were: OS 43% for BC and 35% for MET; LPFS BC 96% and MET 85%; PFS BC 35% and MET 29%. The most frequently observed grade 3 adverse events (AEs) were pneumonitis (5.9% BC, 4.8% MET), pulmonary fibrosis (2.9% BC, 4% MET), and pulmonary embolism (2.9% BC, 0.8% MET). The favorable prognostic effects on overall survival of patients with MET were female gender (log-rank:p < 0.001), no systemic progression (log-rank;p = 0.048, multivariate COX regressionp = 0.039), and malignant melanoma histology (log-rank;p = 0.015, multivariate COX regressionp = 0.020). For patients with BC, it was tumor location within the lower lobe (vs. upper lobe, log-rankp = 0.027). LPFS of patients with metastatic disease was beneficially influenced by female gender (log-rank:p = 0.049).

Conclusion

The treatment concept of 12 × 6 Gy is associated with 96% local progression-free survival for BC and 85% for pulmonary metastases after 3 years. There was no difference in response after SRT of primary lung carcinoma or pulmonary metastases.