bluuebunny/crossref_metadata_2025 huggingface dataset:
The Merger of Isocyanide‐Based Multicomponent Reaction and Ring‐Closing Metathesis (IMCR/RCM)
Authors: Pharande Shrikant G.
Published: January 2021

Isocyanide‐based multicomponent reaction (IMCR) is an excellent synthetic tool for the synthesis of versatile and complex organic molecules in a one‐pot manner. Their extraordinary ability in generating intermediate adducts bearing bi‐ or multi‐functional groups helps in the construction of even more complex products via their combination with various post‐transformation processes. Another efficient tool in modern organic synthesis is the ruthenium‐catalyzed ring‐closing olefin metathesis (RCM). Merging both expedient reactions would give us an extremely powerful approach towards the facile synthesis of complex cyclic olefins which are otherwise difficult to access. Despite their vast utility in various fields of organic chemistry, there is not a single exclusively devoted review on the potential synthetic utility of the IMCR/RCM merger. Thus, in this review, we have discussed the numerous useful IMCR/RCM combination strategies for the synthesis of cyclic olefins from the literature from 1999 until 2019. This review is organized according to the ring size formed during the process.
Direct hydroxylation of 1,4‐Dichlorobenzene to 2,5‐Dichlorophenol over Activated Carbon Catalysts
Authors: Guo Lixian , Liu Li , Pang Conglin , Li Guiying , Hu Changwei
Published: January 2021

The direct hydroxylation of 1,4‐dichlorobenzene (1,4‐DCB) to 2,5‐dichlorophenol (2,5‐DCP) with green oxidant, to replace the conventional multi‐step processes attracted much attention. In this work, activated carbons were prepared by modification firstly using nitric acid, and then the resultant samples were treated with hydrogen peroxide or thermally under nitrogen flow. The prepared samples were applied as heterogeneous catalysts in the one‐step hydroxylation of 1,4‐DCB, and were characterized by XRD, BET, XPS, and Boehm titration. Acetonitrile, isopropanol, glacial acetic acid, and the mixture of them were used as the reaction solvents and EPR was carried to characterize the reaction systems in these solvents. The reaction parameters, such as the feeding speed of H2O2, moles of 1,4‐DCB used, molar ratio of H2O2 to 1,4‐DCB, mass ratio of catalyst to 1,4‐DCB, reaction temperature, and reaction time were optimized. It was found that the direct hydroxylation of 1,4‐DCB could be efficiently catalyzed by activated carbon with acetonitrile as a suitable solvent. Under the optimized conditions, the highest 2,5‐DCP yield of 14.4 % with selectivity of 86.4 % was obtained. The amount of oxygen functional groups on the activated carbon samples resulted in differences in adsorption capacity of 1,4‐DCB and decomposition rate of H2O2, the integrated effect of which might be responsible for the activity.
Connecting the dots: A network approach to post‐traumatic stress symptoms in Chinese healthcare workers during the peak of the Coronavirus Disease 2019 outbreak
Authors: Hoorelbeke Kristof , Sun Xiaoxiao , Koster Ernst H. W. , Dai Qin
Published: January 2021

Healthcare workers are at elevated risk to develop symptoms of post‐traumatic stress disorder (PTSD) in response to an outbreak of a highly infectious disease. The current study set‐out to model the complex interrelations between PTSD symptoms during the peak of the Coronavirus Disease 2019 outbreak in 291 Chinese healthcare workers and 291 matched control cases that were selected from the general population. For this purpose, we estimated regularized partial correlation networks. Within the network of healthcare workers, we observed a central role for avoidance of reminders of the traumatic event, physiological cue reactivity, anger/irritability, re‐experiencing, and startle. We identified three clusters of closely interconnected PTSD symptoms in healthcare workers, consisting of (a) symptoms of re‐experiencing and anxious arousal, (b) symptoms of avoidance and amnesia and (c) symptoms of emotional numbing and dysphoric arousal. Respectively, startle, avoidance of reminders and feeling detached emerged as bridging nodes in these communities. Although yielding highly similar network models, the PTSD symptom structure of healthcare workers showed several unique features compared to the matched control sample. This is informative for interventions aimed at targeting PTSD symptoms in healthcare workers in the context of a public health emergency.
Understanding Superatomic Ag Nanohydrides
Authors: He Xiang , Walter Michael , Jiang De‐en
Published: January 2021

Bulk Ag hydrides are extremely challenging to make even at very high pressures, but they may become stable as the particle size shrinks to the nanometer regime. Here, the formation and electronic structure of Ag nanohydrides are investigated from a superatomic perspective by density functional theory. It is found that as the coverage increases, adsorption energy of hydrogen atoms on Ag38 cluster to form Ag38H2n nanohydride (n is from 1 to 15) can be energetically favorable with respect to bare Ag38 and H2. Furthermore, the adsorbed hydrogen atoms contribute their 1s electrons to the superatom electron count and behave as a metal instead of a ligand. The electronic structure of the silver nanohydrides follows the superatomic complex model, leading to magic or relatively more stable compositions such as Ag38H2, Ag38H20, and Ag38H30, which correspond to 40‐electron, 58‐electron, and 68‐electron shell closings, respectively. Angular momentum analyses of the superatomic orbitals suggest a convoluted interaction of geometry, symmetry, and orbital splitting.
Carbon‐Supported Single Metal Site Catalysts for Electrochemical CO2 Reduction to CO and Beyond
Authors: Zhu Yuanzhi , Yang Xiaoxuan , Peng Cheng , Priest Cameron , Mei Yi , Wu Gang
Published: January 2021

The electrochemical CO2 reduction reaction (CO2RR) is a promising strategy to achieve electrical‐to‐chemical energy storage while closing the global carbon cycle. The carbon‐supported single‐atom catalysts (SACs) have great potential for electrochemical CO2RR due to their high efficiency and low cost. The metal centers’ performance is related to the local coordination environment and the long‐range electronic intercalation from the carbon substrates. This review summarizes the recent progress on the synthesis of carbon‐supported SACs and their application toward electrocatalytic CO2 reduction to CO and other C1 and C2 products. Several SACs are involved, including MNx catalysts, heterogeneous molecular catalysts, and the covalent organic framework (COF) based SACs. The controllable synthesis methods for anchoring single‐atom sites on different carbon supports are introduced, focusing on the influence that precursors and synthetic conditions have on the final structure of SACs. For the CO2RR performance, the intrinsic activity difference of various metal centers and the corresponding activity enhancement strategies via the modulation of the metal centers’ electronic structure are systematically summarized, which may help promote the rational design of active and selective SACs for CO2 reduction to CO and beyond.
Nanotechnology for Hepatocellular Carcinoma: From Surveillance, Diagnosis to Management
Authors: Wu Han , Wang Ming‐Da , Liang Lei , Xing Hao , Zhang Cheng‐Wu , Shen Feng , Huang Dong‐Sheng , Yang Tian
Published: January 2021

Hepatocellular carcinoma (HCC) remains the fourth leading cause of cancer‐related death worldwide. However, the clinical diagnosis and treatment modalities are still relatively limited, which urgently require the development of new effective technologies. Recently, nanotechnology has gained extensive attention in HCC surveillance, imaging and pathological diagnosis, and therapeutic strategies. Typically, nanomedicines have been focused on early HCC diagnosis and precise treatment of advanced HCC, which has developed and improved a variety of new technologies and agents for future clinical practice. Furthermore, strategies of facilitating drug release and delivery in current treatment processes such as ablation, systematic therapy, transcatheter arterial chemoembolization, molecular targeted therapy, and immune‐modulating therapy have also been studied widely. This review summarizes the recent advances in this area according to current clinical HCC guidelines: 1) Nanoparticle‑based HCC surveillance; 2) Nanotechnology for HCC diagnosis; 3) Therapeutic advances for HCC Management; 4) Limitations of applications in nanotechnology for HCC; 5) Conclusions and perspectives. Although there are still many limitations and difficulties to overcome, the investigations of nanomedicines are believed to show potential applications in clinical practice.
Visible‐Light Induced Sustainable Water Treatment Using Plasmo‐Semiconductor Nanogap Bridge Array, PNA
Authors: Murphy Emma , Liu Yunbo , Krueger Daniel , Prasad Meghna , Lee Somin Eunice , Park Younggeun
Published: January 2021

The development of sustainable methods for energy‐intensive water treatment processes continues to be a challenging issue. Plasmonic‐semiconductor nanoparticles, which absorb large amounts of sunlight in the visible range for conversion into chemical energy efficiently, can form the basis of a sustainable water treatment method. However, the potential uses of plasmonic semiconductor particles for water treatment have not been fully explored yet because of the limitations associated with the imbalance between light capture, charge transfer, and the required recycling steps for the particles themselves. Herein, a significantly improved visible‐light‐induced water treatment method that uses a plasmo‐semiconductor nanogap bridge array (PNA) is reported. As an arrangement of antenna‐reactors, the PNA enables the balancing of the largely enhanced electromagnetic field in the plasmonic nanogap coupling region and optimal separation of charge carriers in the semiconductor. The simultaneous effects of visible‐light absorption and charge transfer lead to the generation of a highly enhanced visible‐light‐induced OH radical (•OH). Consequently, visible‐light‐induced 5‐log N/N0 water disinfection and 100% chemical decomposition for sustainable water treatment were demonstrated. Owing to the large light absorption, charge carrier utilization, and array‐oriented scalability, the PNA will be valuable in various sustainable energy and environmental applications.
Band Edge Engineering for the Improvement of Open‐Circuit Voltage: Ag‐Based Selenized Cu2ZnSn(SSe)4 Surface Regulated by Lithium
Authors: Cui Yingru , Zhao Ke , Liu Chengyan , Xiang Huiwen , Liang Hanzhen , Jia Yu
Published: January 2021

Open‐circuit voltage (Voc) of kesterite Cu2ZnSn(SSe)4 (CZTSSe) solar cells is severely stalemated by the pinning of fermi energy level due to the excessive p‐type CuZn acceptor near the buffer/absorber interface. Although the formation of CuZn can be suppressed by Ag incorporation, the high formation energy of p‐type AgZn defects results in the expected weak n‐type surface difficult to be maintained. Based on the doping limit rule, it is found that Ag‐based selenized kesterite (Ag2ZnSnSe4) facilitating the formation of n‐type defects by lowering the conduction band is conducive to the stable weak n‐type surface rather than suppressing the formation of p‐type defects by lowering the valence band. Furthermore, Li post‐treatment makes part of strong n‐type region into the expected weak n‐type due to the low formation energy of p‐type LiZn, which is greatly convenient for experimental implementation. This study presents that Ag‐based selenized CZTSSe surface combined with Li post‐treatment is a feasible way to overcome Voc‐deficit of kesterite solar cells and highlights that band edge engineering is a promising way for designing an expected n‐ or p‐type characteristic of chalcogenide semiconductors by extrinsic doping.
Exploring reliable edge‐cloud computing for service latency optimization in sustainable cyber‐physical systems
Authors: Cao Kun , Wei Tongquan , Chen Mingsong , Li Keqin , Weng Jian , Tan Wuzheng
Published: January 2021

In recent years, the advance in information technology has promoted a wide span of emerging cyber‐physical systems (CPS) applications such as autonomous automobile systems, healthcare monitoring, and process control systems. For these CPS applications, service latency management is extraordinarily important for the sake of providing high quality‐of‐experience to terminal users. Edge‐cloud computing, integrating both edge computing and cloud computing, is regarded as a promising computation paradigm to achieve low service latency for terminal users in CPS. However, existing latency‐aware edge‐cloud computing methods dedicated for CPS fail to jointly consider energy budgets and reliability requirements, which may greatly degrade the sustainability of CPS applications. In this article, we explore the problem of minimizing service latency of edge‐cloud computing coupled CPS under the constraints of energy budgets and reliability requirements. We propose a two‐stage approach composed of static and dynamic service latency optimization. At static stage, Monte‐Carlo simulation with integer‐linear‐programming technique is adopted to find the optimal computation offloading mapping and task backup number. At dynamic stage, a backup‐adaptive dynamic mechanism is developed to avoid redundant data transmissions and executions for achieving additional energy savings and service latency enhancement. Experimental results show that our solution is able to reduce system service latency by up to 18.3% compared with representative baseline solutions.
Providing high‐level self‐adaptive abstractions for stream parallelism on multicores
Authors: Vogel Adriano , Griebler Dalvan , Fernandes Luiz Gustavo
Published: January 2021

Stream processing applications are common computing workloads that demand parallelism to increase their performance. As in the past, parallel programming remains a difficult task for application programmers. The complexity increases when application programmers must set nonintuitive parallelism parameters, that is, the degree of parallelism. The main problem is that state‐of‐the‐art libraries use a static degree of parallelism and are not sufficiently abstracted for developing stream processing applications. In this article, we propose a self‐adaptive regulation of the degree of parallelism to provide higher‐level abstractions. Flexibility is provided to programmers with two new self‐adaptive strategies, one is for performance experts, and the other abstracts the need to set a performance goal. We evaluated our solution using compiler transformation rules to generate parallel code with the SPar domain‐specific language. The experimental results with real‐world applications highlighted higher abstraction levels without significant performance degradation in comparison to static executions. The strategy for performance experts achieved slightly higher performance than the one that works without user‐defined performance goals.
Formation and Control of Transverse Corner Cracks in the Continuous Casting Slab of a Microalloyed Steel
Authors: Wang Yadong , Ren Qiang , Zhang Lifeng , Yang Xiaogang , Yang Wen , Ren Ying , Zhang Haijie
Published: January 2021

To investigate transverse corner cracks for a microalloyed steel continuous casting slab, the metallography, microtopography, and three‐dimensional (3D) morphology of cracks are studied, respectively. High‐temperature mechanical properties are investigated and compared from two positions where samples are extracted from both the slab corner and surface of the slab center. The thermal history of the slab is simulated and optimized experiments are conducted. Transverse corner cracks are generated on the valley of oscillation marks. Mold powder and wear elements of the mold are not detected. Microstructures are refined near the cracks. Cracks are generated in secondary cooling zones and the cracking temperature is higher than Ar3 temperature. The extension path of cracks is not linear and cracks extend along the grain boundary. The third brittle temperature ranges (TBTR) are 764–832 °C and 793–808 °C in the two positions, respectively. The temperature at the slab corner in the bending and straightening zone falls into the brittle zone during the original water cooling condition, leading to the formation of cracks. The secondary cooling scheme is optimized to prevent the temperature at the slab corner in the bending and straightening zone from entering the TBTR, significantly reducing the occurrence of transverse corner cracks.
Design process for system of systems reconfigurations
Authors: Petitdemange Franck , Borne Isabelle , Buisson Jérémy
Published: January 2021

Systems of systems (SoSs) constitute a particular class of systems, whose constituents are themselves systems in their own right. Such systems present architectures that dynamically change in a way that is not necessarily intended at the time of design. We target a kind of SoS that is subject to evolutionary development and propose a reconfiguration design process that guides the architect in charge of SoS engineering by indicating the tasks that must be accomplished to develop a reconfiguration for evolutionary development. Finally, our process is applied to design a reconfiguration in the context of a realistic case study inspired by the French emergency services .
Effects of Constant Parameters on Optimum Design of Axially Symmetric Cylindrical Reinforced Concrete Walls
Authors: Kayabekir Aylin Ece
Published: January 2021

This paper presents a metaheuristic‐based optimization methodology for optimum design of axially symmetric cylindrical reinforced concrete walls that are a type of thin shells. In the methodology, recently proposed metaheuristic algorithm called Jaya algorithm is conducted with well‐known method called flexibility theory. The thickness of the wall is defined as a design variable of the optimization problem and the total material cost, including concrete and steel bars, is the objective function. Reinforced concrete design is done according to rules of regulation ACI 318‐Building code requirements for structural concrete. The proposed method is performed for different numerical cases of design constants to investigate effects of the wall height, dome height and thickness, and specific weight of stored liquid on optimum parameters for different support conditions. The investigation includes the optimum design of axially symmetric cylindrical reinforced concrete walls with and without domes. Analyzes were done for a total of 13,650 different situations, and various expressions such as linear, parabolic, and exponential were also proposed to assist engineers in their practical applications. According to the results of the analysis, it has been revealed that each investigated case has an effect on the optimum results and the proposed equations are successful in finding values quite close to the optimum design.
Lihengia: A new genus of Asteraceae distinct from Dubyaea
Authors: Chen You‐Sheng , Xu Lian‐Sheng , Ke Rui , Harris Aj , Li Hui‐Min
Published: January 2021

A new genus, Lihengia, is established for two species presently treated within Dubyaea, which is proved to be paraphyletic in the present study, even after exclusion of Lihengia. Dubyaea is a genus of about 15 species endemic to the Sino‐Himalayan region that are treated within subtribe Crepidinae of tribe Cichorieae within Asteraceae. Stebbins suggested that Dubyaea may contain species representing direct ancestors of several widerspread genera in tribe Cichorieae, thus making phylogenetic reconstruction challenging. We tested the monophyly of Dubyaea using a molecular phylogeny reconstructed from ITS and five plastid fragment sequences (petD, psbA‐trnH, 5′trnL(UAA)‐trnF, rpl32‐trnL(UAG), trnQ(UUG)‐5′rps16) and sampling comprising Dubyaea and related species within the tribe Cichorieae. We resolved Dubyaea species within at least two separate clades of tribe Cichorieae. Most species of Dubyaea occurred in subtribe Crepidinae, while Dubyaea sect. Amoena was placed in subtribe Lactucinae. Based on our findings, we erect Lihengia as a new genus to accommodate the species of D. sect. Amoena, and, consequently, we propose two new combinations. We discuss the morphological and cytological support for the new genus.
Maximum Allowable Output Power and Optimum Capacity of PV Generator in Power Distribution System under Constant Output Power Control of Power Conditioning System
Authors: Tsusaka Akihiro , Tsukamoto Masumi , Isobe Yuka , Nakao Toshiki , Matsumura Toshiro , Yukita Kazuto , Goto Yasuyuki , Yokomizu Yasunobu , Iioka Daisuke , Shimizu Hirotaka , Iwatsuki Hideki , Kunii Yasuyuki , Uenishi Hirokazu , Ishikawa Hiroyuki , Fukae Takayuki , Mineta Yuto , Kanazawa Yuki
Published: January 2021

In recent years, it has been discovered that the magnitude of the connection node voltage is affected by the output power from a photovoltaic (PV) generator and the line impedance when the PV generator, in an increasing trend, is introduced into the distribution system. In this paper, power flow is qualitatively discussed using basic circuit theory comprising the voltage and current vector diagram. A magnitude and its operation point of the maximum allowable output power from the PV generator were successfully derived in the vector diagram where the power conditioning system was operated with a constant output power and constant power factor controls. Furthermore, an optimum capacity of the PV generator was also clarified in the vector diagram to effectively utilize the output power of the PV generator. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
Achieving a good impression: Reputation management and performance goals
Authors: Good Kayla , Shaw Alex
Published: January 2021

Whether a student wants to improve their ability (i.e., has learning goals) or demonstrate it (i.e., has performance goals) plays an important role in their learning and motivation; students focused on the latter tend to avoid taking on challenges and seeking help when they need it. In the achievement literature, these different goals are thought to result primarily from holding different mindsets about whether one's ability is malleable or fixed. We argue, however, that this traditional framework has largely overlooked the powerful role that reputational concerns play in influencing which achievement goals students pursue. Specifically, reputational concerns may drive students to pursue performance goals and “prove” their ability to others, irrespective of their mindsets. We argue that closely investigating these concerns may help uncover new mechanisms by which performance goals are fostered and maintained as well as new strategies for developing interventions aimed at encouraging learning goals. Finally, we offer suggestions for how the achievement and reputation management literatures can be productively brought to bear on one another in future research.

This article is categorized under:

Psychology > Reasoning and Decision Making

Psychology > Emotion and Motivation

Psychology > Development and Aging
Wind turbine event detection by support vector machine
Authors: Hu Congcong , Albertani Roberto
Published: January 2021

Considering the increase in the deployment of wind energy conversion systems, improving the coexistence between wind turbines and wildlife with an efficient method for blade impact assessment is of primary importance. Automated blade‐impacts on potential wildlife monitoring can support the development and operations of wind farms. A substantial challenge is represented by the typical case of impacts vibrations signature embedded in the operational vibrations of the wind turbine. A heterogeneous multisensor system for automatic eagle detection and deterrent, including an automatic blade‐event detection module, was developed providing the necessary field data. An automated blade event detection system, based on support vector machine, a form of machine learning, was developed and tested. Training of the algorithm was performed using features extracted from vibration signals and energy distribution graphs obtained from numerical simulations of blade impacts. Performance of the method, evaluated using numerical simulations at different levels of signal‐to‐noise ratios, relative to artificial impacts, showed the best results when trained using combined raw vibration signal and time marginal integration graphs, exhibiting an overall accuracy of 93% at
. The proposed model was tailored for improving specificity (i.e., false negative error), a critical aspect for endangered species events. Performance of the trained algorithm evaluating field data exhibited an improvement in impact detection from a visually identifiable rate of 42% to true positive prediction rate of 75%. The system could perform, with appropriate training, diverse functions as components health monitoring or lighting strike automatic monitoring.
Review of life cycle greenhouse gases, air pollutant emissions and costs of road medium and heavy‐duty trucks
Authors: Machado Pedro G. , Teixeira Ana C. R. , Collaço Flavia M. A. , Mouette Dominique
Published: January 2021

The desired energy transition to guarantee net‐zero greenhouse gases (GHGs) emissions needs to take place in every sector of the global economy. The transport sector is responsible for a large share of energy consumption and GHGs emissions while contributing to the increase in air pollution. Although new technologies are available, the use of diesel in road transport is still predominant. These new technologies, nonetheless, still present inconsistencies in their environment, economic performances and do not necessarily provide improvements when considering the entire fuel life cycle used in medium and heavy‐duty trucks. This systematic review addresses the uncertainties in life cycle studies regarding the road transport sector fuel consumption, GHGs, and air pollutant emissions economic analyses. Results show that there are higher chances of reducing GHGs emissions through biogas or fuel‐cell hydrogen trucks, while PM2.5and NOx emissions have higher chances of being reduced with fuel‐cell hydrogen or natural gas trucks. There is, however, a reduced interest by the scientific community in the transport literature in dealing with air pollutants, and the focus is mainly on GHGs emissions. When it comes to economic viability, natural gas and hybrid trucks are the best substitutes.

This article is categorized under:

Energy and Transport > Economics and Policy

Energy and Transport > Climate and Environment

Energy and Climate > Climate and Environment
The clinical characterization of the patient with primary psychosis aimed at personalization of management
Authors: Maj Mario , van Os Jim , De Hert Marc , Gaebel Wolfgang , Galderisi Silvana , Green Michael F. , Guloksuz Sinan , Harvey Philip D. , Jones Peter B. , Malaspina Dolores , McGorry Patrick , Miettunen Jouko , Murray Robin M. , Nuechterlein Keith H. , Peralta Victor , Thornicroft Graham , van Winkel Ruud , Ventura Joseph
Published: January 2021

The current management of patients with primary psychosis worldwide is often remarkably stereotyped. In almost all cases an antipsychotic medica­tion is prescribed, with second‐generation antipsychotics usually preferred to first‐generation ones. Cognitive behavioral therapy is rarely used in the vast majority of countries, although there is evidence to support its efficacy. Psychosocial interventions are often provided, especially in chronic cases, but those applied are frequently not validated by research. Evidence‐based family interventions and supported employment programs are seldom implemented in ordinary practice. Although the notion that patients with primary psychosis are at increased risk for cardiovascular diseases and diabetes mellitus is widely shared, it is not frequent that appropriate measures be implemented to address this problem. The view that the management of the patient with primary psychosis should be personalized is endorsed by the vast majority of clinicians, but this personalization is lacking or inadequate in most clinical contexts. Although many mental health services would declare themselves “recovery‐oriented”, it is not common that a focus on empowerment, identity, meaning and resilience is ensured in ordinary practice. The present paper aims to address this situation. It describes systematically the salient domains that should be considered in the characterization of the individual patient with primary psychosis aimed at personalization of management. These include positive and negative symptom dimensions, other psychopathological components, onset and course, neurocognition and social cognition, neurodevelopmental indicators; social functioning, quality of life and unmet needs; clinical staging, antecedent and concomitant psychiatric conditions, physical comorbidities, family history, history of obstetric complications, early and recent environmental exposures, protective factors and resilience, and internalized stigma. For each domain, simple assessment instruments are identified that could be considered for use in clinical practice and included in standardized decision tools. A management of primary psychosis is encouraged which takes into account all the available treatment modalities whose efficacy is supported by research evidence, selects and modulates them in the individual patient on the basis of the clinical characterization, addresses the patient’s needs in terms of employment, housing, self‐care, social relationships and education, and offers a focus on identity, meaning and resilience.
A Fluorescent Titanium‐based Metal‐Organic Framework Sensor for Nitro‐aromatics Detection
Authors: Zhang Xin , Yan Yu , Chen Faqiang , Bai Gongxun , Xu Hui , Xu Shiqing
Published: January 2021

A rare fluorescent nanoscale titanium‐based metal‐organic framework (MOF) material, Ti6(μ3‐O)6(μ2‐OH)6(BTB)2(DMF)2 (ZSTU‐2) was synthesized and realized for highly sensitive sensing of nitro‐aromatic compounds. ZSTU‐2 exhibited high fluorescence intensity with blue luminescence and stability in water. ZSTU‐2 exhibited significant luminescent quenching effects upon the addition of nitro‐aromatic compounds, especially for picric acid (PA). The limit of detection (LOD) for PA reaches 2.37 μM and the Ksv value is 2.266×104 M−1.
Dark initial state radiation and the kinetic mixing portal
Authors: Rizzo Thomas G.
Published: January 2021

Abstract

Data from Planck measurements of the cosmic microwave background (CMB) place important constraints on models with light dark matter (DM) and light mediators especially when both lie in the mass range below∼1 GeV. In models involving kinetic mixing where the dark photon acts as the mediator, these constraints are easily satisfied and the appropriate DM relic density achievable if the DM is, e.g., a complex scalar, wherep-wave annihilation occurs, or is the lighter component of a split pseudo-Dirac state where co-annihilation dominates. In both of these cases, although higher order in the dark gauge coupling,gD, the corresponding annihilation processes including dark photon initial state radiation (ISR) will be dominantlys-wave with essentially temperature independent cross sections. The rates for these dark ISR associated processes, though not yielding cross sections large enough to contribute to the relic density, can still run into possible conflicts with the bounds arising from the CMB. In this paper we perform a preliminary study of the present and potential future constraints that the CMB imposes on the parameter spaces for both of these scenarios due to the existence of this dark ISR. Further analyses of the effects of dark ISR in DM annihilation is clearly warranted.
A high-frequency non-resonant elliptical vibration-assisted cutting device for diamond turning microstructured surfaces
Authors: Wang Zhengjian , Luo Xichun , Liu Haitao , Ding Fei , Chang Wenlong , Yang Liang , Zhang Jianguo , Cox Andrew
Published: January 2021

In recent years, research has begun to focus on the development of non-resonant elliptical vibration-assisted cutting (EVC) devices, because this technique offers good flexibility in manufacturing a wide range of periodic microstructures with different wavelengths and heights. However, existing non-resonant EVC devices for diamond turning can only operate at relatively low frequencies, which limits their machining efficiencies and attainable microstructures. This paper concerns the design and performance analysis of a non-resonant EVC device to overcome the challenge of low operational frequency. The structural design of the non-resonant EVC device was proposed, adopting the leaf spring flexure hinge (LSFH) and notch hinge prismatic joint (NHPJ) to mitigate the cross-axis coupling of the reciprocating displacements of the diamond tool and to combine them into an elliptical trajectory. Finite element analysis (FEA) using the mapped meshing method was performed to assist the determination of the key dimensional parameters of the flexure hinges in achieving high operational frequency while considering the cross-axis coupling and modal characteristics. The impact of the thickness of the LSFH on the sequence of the vibrational mode shape for the non-resonant EVC device was also quantitatively revealed in this study. Moreover, a reduction in the thickness of the LSFH can reduce the natural frequency of the non-resonant EVC device, thereby influencing the upper limit of its operational frequency. It was also found that a decrease in the neck thickness of the NHPJ can reduce the coupling ratio. Experimental tests were conducted to systematically evaluate the heat generation, cross-axis coupling, modal characteristics and diamond tool’s elliptical trajectory of a prototype of the designed device. The test results showed that it could operate at a high frequency of up to 5 kHz. The cross-axis coupling ratio and heat generation of the prototype are both at an acceptable level. The machining flexibility and accuracy of the device in generating microstructures of different wavelengths and heights through tuning operational frequency and input voltage have also been demonstrated via manufacturing the micro-dimple arrays and two-tier microstructured surfaces. High-precision microstructures were obtained with 1.26% and 10.67% machining errors in wavelength and height, respectively.
Absence of the celiac trunk and anomalous very low origin of the common hepatic artery arising independently from the abdominal aorta just above aortic bifurcation in patient undergoing radical pancreaticoduodenectomy
Authors: Mrowiec Sławomir , Król Robert , Jabłońska Beata
Published: January 2021

Purpose

Knowledge of anomalies of the celiac trunk is very important during various surgical procedures (such as pancreatic and gastric resections including Appleby operation, liver resections and liver transplantations) and as well as radiologic procedures (such as chemoembolization of pancreatic and hepatic tumors).

Methods

A 77-years-old woman was admitted to our department for surgical treatment of ampullary adenocarcinoma G2 confirmed in endoscopic retrograde cholangiopancreatography (ERCP) with papillotomy and ampullary biopsy. In the contrast-enhanced computed tomography, the ampullary tumor was not visible, but the main pancreatic duct within pancreatic head and isthmus was dilated (indirect radiological tumor signs). An absence of the celiac trunk (CT) was established via computed tomography. Therefore, computed tomography-based angiography (angio-CT) of the abdominal aorta (AA) was performed before operation.

Results

Angio-CT confirmed an extremely rare vascular anomaly: an absence of CT. The left gastric (LGA), splenic (SA), and common hepatic (CHA) arteries connected above origin of the superior mesenteric artery (SMA) from the AA. Pylorus-preserving pancreaticoduodenectomy (PD) was performed. This anomaly was also confirmed intraoperatively. The postoperative course was uneventful and the patient was discharged on postoperative day 10. There were no signs of recurrence of the tumor during the 6 months follow-up.

Conclusion

The proper preoperative identification of anomalies within major abdominal vessels and its relationship to the tumor is very important to avoid intraoperative vascular injury and major postoperative complications.
The mechanism of filler items in the response time concealed information test
Authors: Lukács Gáspár , Ansorge Ulrich
Published: January 2021

The response time concealed information test (RT-CIT) can reveal that a person recognizes a relevant (probe) item among other, irrelevant items, based on slower responding to the probe compared to the irrelevant items. Therefore, if this person is concealing the knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be unveiled. Adding familiarity-related filler items to the task has been shown to substantially increase the validity of the method, but assumptions for this effect have never been tested before. In the present series of three experiments (N = 511), we tested several factors, most of which were found to indeed influence the enhancing effects of fillers. First, larger enhancement is achieved when a smaller proportion of fillers shares the response key with the target. Second, familiarity context does play a role in the enhancement, and the target sharing its response key with the familiarity-referring fillers leads to larger enhancement. Third, mere symbolic fillers (such as simple arrow-like characters) also lead to enhancement, but filler words without task-relevant meaning are not effective. Fourth, small visual differences (lettercase or underlining) between fillers and the rest of the items have no significant influence. All this provides justification for the original structure of the fillers and also demonstrates that the enhancement is highly generalizable: Fillers have a potential to improve the RT-CIT regardless of deception scenario, item types, or the examinee's language comprehension.
Ecological, (epi)genetic and physiological aspects of bet-hedging in angiosperms
Authors: Gianella Maraeva , Bradford Kent J. , Guzzon Filippo
Published: January 2021

Key message

Bet-hedging is a complex evolutionary strategy involving morphological, eco-physiological, (epi)genetic and population dynamics aspects. We review these aspects in flowering plants and propose further research needed for this topic.

Bet-hedging is an evolutionary strategy that reduces the temporal variance in fitness at the expense of a lowered arithmetic mean fitness. It has evolved in organisms subjected to variable cues from the external environment, be they abiotic or biotic stresses such as irregular rainfall or predation. In flowering plants, bet-hedging is exhibited by hundreds of species and is mainly exerted by reproductive organs, in particular seeds but also embryos and fruits. The main example of bet-hedging in angiosperms is diaspore heteromorphism in which the same individual produces different seed/fruit morphs in terms of morphology, dormancy, eco-physiology and/or tolerance to biotic and abiotic stresses in order to ‘hedge its bets’ in unpredictable environments. The objective of this review is to provide a comprehensive overview of the ecological, genetic, epigenetic and physiological aspects involved in shaping bet-hedging strategies, and how these can affect population dynamics. We identify several open research questions about bet-hedging strategies in plants: 1) understanding ecological trade-offs among different traits; 2) producing more comprehensive phylogenetic analyses to understand the diffusion and evolutionary implications of this strategy; 3) clarifying epigenetic mechanisms related to bet-hedging and plant responses to environmental cues; and 4) applying multi-omics approaches to study bet-hedging at different levels of detail. Clarifying those aspects of bet-hedging will deepen our understanding of this fascinating evolutionary strategy.
Population genetics and host specificity of Varroa destructor mites infesting eastern and western honeybees
Authors: Lin Zheguang , Wang Shuai , Neumann Peter , Chen Gongwen , Page Paul , Li Li , Hu Fuliang , Zheng Huoqing , Dietemann Vincent
Published: January 2021

In a globalized world, parasites are often brought in contact with new potential hosts. When parasites successfully shift host, severe diseases can emerge at a large cost to society. However, the evolutionary processes leading to successful shifts are rarely understood, hindering risk assessment, prevention, or mitigation of their effects. Here, we screened populations ofVarroa destructor, an ectoparasitic mite of the honeybee genusApis, to investigate their genetic structure and reproductive potential on new and original hosts. From the patterns identified, we deduce the factors that influenced the macro- and microevolutionary processes that led to the structure observed. Among the mite variants identified, we found two genetically similar populations that differed in their reproductive abilities and thus in their host specificity. These lineages could interbreed, which represents a threat due to the possible increased virulence of the parasite on its original host. However, interbreeding was unidirectional from the host-shifted to the nonshifted native mites and could thus lead to speciation of the former. The results improve our understanding of the processes affecting the population structure and evolution of this economically important mite genus and suggest that introgression between shifted and nonshifted lineages may endanger the original host.
Effectiveness of cetuximab as preemptive postsurgical therapy for oral squamous cell carcinoma patients with major risk: a single‐center retrospective cohort study
Authors: Fukumoto Chonji , Sawatani Yuta , Shiraishi Ryo , Zama Manabu , Shimura Michiko , Hasegawa Tomonori , Komiyama Yuske , Fujita Atsushi , Wakui Takahiro , Kawamata Hitoshi
Published: January 2021

A retrospective cohort study was performed to investigate the effectiveness of preemptive postsurgical therapy with cetuximab for patients with a major risk of recurrence or metastasis after clinical complete resection of primary oral squamous cell carcinoma (OSCC). The study period was from 2007 to 2019 for patients treated at the Department of Oral and Maxillofacial Surgery, Dokkyo Medical University School of Medicine. OSCC patients with major risk (n = 88) in the follow-up period were divided into groups with no postsurgical treatment (NP group), with standard postsurgical treatment (SP group), and with postsurgical treatment including cetuximab (CP group), and prognosis were compared among those groups. The 5-year overall survival rate was significantly higher in patients who received postsurgical treatment with cetuximab (CP) compared to that in the other two groups ((CP vs. NP, p = 0.028; CP vs. SP, p = 0.042). Furthermore, we performed multivariate analysis to evaluate the effects of the main components of the treatment. Among CDDP, radiotherapy, and cetuximab, only cetuximab significantly contributed to improved survival by univariate analysis (crude HR:0.228, 95%CI:0.05–0.968, p = 0.045). cetuximab also showed the same tendency in multivariate analysis, although p value did not reach significant level (Adjusted HR: 0.233, 95%CI: 0.053–1.028, p = 0.054). The results suggest that the postsurgical treatment with cetuximab as a preemptive postsurgical therapy after complete surgical resection of a visible tumor is considerably effective for OSCC patients with major risk, in other words, invisible dormant metastasis.
The Proteins of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2 or n-COV19), the Cause of COVID-19
Authors: Yoshimoto Francis K.
Published: January 2021

The devastating effects of the recent global pandemic (termed COVID-19 for “coronavirus disease 2019”) caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) are paramount with new cases and deaths growing at an exponential rate. In order to provide a better understanding of SARS CoV-2, this article will review the proteins found in the SARS CoV-2 that caused this global pandemic.
RNA and DNA Binding Epitopes of the Cold Shock Protein TmCsp from the Hyperthermophile Thermotoga maritima
Authors: von König Konstanze , Kachel Norman , Kalbitzer Hans Robert , Kremer Werner
Published: January 2021

Prokaryotic cold shock proteins (CSPs) are considered to play an important role in the transcriptional and translational regulation of gene expression, possibly by acting as transcription anti-terminators and “RNA chaperones”. They bind with high affinity to single-stranded nucleic acids. Here we report the binding epitope of TmCsp from Thermotoga maritima for both single-stranded DNA and RNA, using heteronuclear 2D NMR spectroscopy. At “physiological” growth temperatures of TmCsp (≥ 343 K), all oligonucleotides studied have dissociation constants between 1.6 ((dT)7) and 25.2 ((dA)7) μM as determined by tryptophan fluorescence quenching. Reduction of the temperature to 303 K leads to a pronounced increase of affinity for thymidylate (dT)7 and uridylate (rU)7 heptamers with dissociation constants of 4.0 and 10.8 nM, respectively, whereas the weak binding of TmCsp to cytidylate, adenylate, and guanylate heptamers (dC)7, (dA)7, and (dT)7 is almost unaffected by temperature. The change of affinities of TmCsp for (dT)7 and (rU)7 by approximately 3 orders of magnitude shows that it represents a cold chock sensor that switches on the cold shock reaction of the cell. A temperature dependent conformational switch of the protein is required for this action. The binding epitope on TmCsp for the ssDNA and RNA heptamers is very similar and comprises β-strands 1 and 2, the loop β1–β2 as well as the loops connecting β3 with β4 and β4 with β5. Besides the loop regions, surprisingly, mainly the RNA-binding motif RNP1 is involved in ssDNA and RNA binding, while only two amino acids, H28 and W29, of the postulated RNA-binding motif RNP2 interact with the uridylate and thymidylate homonucleotides, although a high affinity in the nanomolar range is achieved. This is in contrast to the binding properties of other CSPs or cold shock domains, where RNP1 as well as RNP2 are involved in binding. TmCsp takes up a unique position since it is the only one which possesses a tryptophan residue instead of a usually highly conserved phenylalanine or tyrosine residue at the end of RNP2. NMR titrations suggest that neither (dT)7 nor (rU)7 represent the full binding motif and that non-optimal intercalation of W29 into these oligonucleotides blocks the access of the RNP2 site to the DNA or RNA. NMR-experiments with (dA)7 suggest an interaction of W29 with the adenine ring. Full binding seems to require at least one single purine base well-positioned within a thymine- or uracil-rich stretch of nucleic acids.
Using Penalized EM Algorithm to Infer Learning Trajectories in Latent Transition CDM
Authors: Wang Chun
Published: January 2021

Cognitive diagnostic models (CDMs) have arisen as advanced psychometric models in the past few decades for assessments that intend to measure students’ mastery of a set of attributes. Recently, quite a few studies attempted to extend CDMs to longitudinal versions, and they all tended to model transition probabilities from non-mastery to mastery or vice versa for each attribute separately, with an exception of a few studies (e.g., Chen et al. 2018; Madison & Bradshaw 2018). However, these pioneering works have not taken into consideration the attribute relationships and the ever-changing attributes in a learning period. In this paper, we consider a profile-level latent transition CDM (TCDM hereafter), which can not only identify transition probabilities across the same attributes over time, but also the transition pathways across different attributes. Two versions of the penalized expectation-maximization (PEM) algorithms are proposed to shrink the probabilities associated with impermissible transition pathways to 0 and, thereby, help explore attribute relationships in a longitudinal setting. Simulation results reveal that PEM with group penalty holds great promise for identifying learning trajectories.