bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Distinct Structures of Membrane‐Associated Homodimers of GTP‐ and GDP‐Bound KRAS4B Revealed by Paramagnetic Relaxation Enhancement
Authors: Lee Ki‐Young , Fang Zhenhao , Enomoto Masahiro , Gasmi‐Seabrook Genevieve , Zheng Le , Koide Shohei , Ikura Mitsuhiko , Marshall Christopher B. 
Published: March 2020

AbstractKRAS homo‐dimerization has been implicated in the activation of RAF kinases, however, the mechanism and structural basis remain elusive. We developed a system to study KRAS dimerization on nanodiscs using paramagnetic relaxation enhancement (PRE) NMR spectroscopy, and determined distinct structures of membrane‐anchored KRAS dimers in the active GTP‐ and inactive GDP‐loaded states. Both dimerize through an α4–α5 interface, but the relative orientation of the protomers and their contacts differ substantially. Dimerization of KRAS‐GTP, stabilized by electrostatic interactions between R135 and E168, favors an orientation on the membrane that promotes accessibility of the effector‐binding site. Remarkably, “cross”‐dimerization between GTP‐ and GDP‐bound KRAS molecules is unfavorable. These models provide a platform to elucidate the structural basis of RAF activation by RAS and to develop inhibitors that can disrupt the KRAS dimerization. The methodology is applicable to many other farnesylated small GTPases.
Slurry‐Coated Sulfur/Sulfide Cathode with Li Metal Anode for All‐Solid‐State Lithium‐Sulfur Pouch Cells
Authors: Yuan Hong , Nan Hao‐Xiong , Zhao Chen‐Zi , Zhu Gao‐Long , Lu Yang , Cheng Xin‐Bing , Liu Quan‐Bing , He Chuan‐Xin , Huang Jia‐Qi , Zhang Qiang 
Published: March 2020

AbstractAll‐solid‐state lithium‐sulfur batteries are strongly considered as the most promising next‐generation electrochemical energy storage systems due to their high safety and energy density. However, in view of practical application, it is difficult to obtain large‐scale solid‐state sulfur cathode continuously. Herein we achieve the large‐scale fabrication of solid sulfur cathode by a facile slurry‐coating process through the screening of various solvents and binder contents. The composite cathodes in all‐solid‐state lithium‐sulfur pouch cells exhibit a high specific capacity of 1169 mAh g−1 and excellent cycling stability. Furthermore, a practical lithium‐sulfur pouch cell with an areal discharge capacity of up to 2.3 mAh cm−2 is also demonstrated. This work makes a leap towards the practical application of all‐solid‐state lithium‐sulfur batteries.
Introducing the 21st Century's New Four Horsemen of the Coronapocalypse
Authors: Cheong Kang Hao , Jones Michael C. 
Published: March 2020

AbstractAs the world struggles through the COVID‐19 pandemic, we should also be asking what systems‐level measures will be needed to prevent this or even worse disasters from happening in the future. We argue that the pandemic is merely one of potentially myriad and pleiomorphic future global disasters generated by the same underlying dynamical system. We explain that there are four broad but easily identifiable systemic, pathologically networked conditions that are hurtling civilization toward potential self‐destruction. As long as these conditions are not resolved, we should consider catastrophe as an inevitable emergent endpoint from the dynamics. All four conditions can be reversed with collective action to begin creating an enduring and thriving post‐ COVID‐19 world. This will require maximal application of the precautionary principle.
Improved confidence intervals for a difference of two cause‐specific cumulative incidence functions estimated in the presence of competing risks and random censoring
Authors: Scosyrev Emil 
Published: March 2020

AbstractA cause‐specific cumulative incidence function (CIF) is the probability of failure from a specific cause as a function of time. In randomized trials, a difference of cause‐specific CIFs (treatment minus control) represents a treatment effect. Cause‐specific CIF in each intervention arm can be estimated based on the usual non‐parametric Aalen–Johansen estimator which generalizes the Kaplan–Meier estimator of CIF in the presence of competing risks. Under random censoring, asymptotically valid Wald‐type confidence intervals (CIs) for a difference of cause‐specific CIFs at a specific time point can be constructed using one of the published variance estimators. Unfortunately, these intervals can suffer from substantial under‐coverage when the outcome of interest is a rare event, as may be the case for example in the analysis of uncommon adverse events. We propose two new approximate interval estimators for a difference of cause‐specific CIFs estimated in the presence of competing risks and random censoring. Theoretical analysis and simulations indicate that the new interval estimators are superior to the Wald CIs in the sense of avoiding substantial under‐coverage with rare events, while being equivalent to the Wald CIs asymptotically. In the absence of censoring, one of the two proposed interval estimators reduces to the well‐known Agresti–Caffo CI for a difference of two binomial parameters. The new methods can be easily implemented with any software package producing point and variance estimates for the Aalen–Johansen estimator, as illustrated in a real data example.
Sitagliptin affects gastric cancer cells proliferation by suppressing Melanoma‐associated antigen‐A3 expression through Yes‐associated protein inactivation
Authors: Wang Qi , Lu Pan , Wang Tao , Zheng Qianqian , Li Yan , Leng Sean X. , Meng Xin , Wang Biao , Xie Jisheng , Zhang Haiyan 
Published: March 2020

AbstractSitagliptin is an emerging oral hypoglycemic agent that inhibits the development of a wide variety of tumors. Current researches indicate that the abnormal activation of Yes‐associated protein (YAP) promotes the proliferation and poor prognosis of multiple tumors. However, the ability of sitagliptin to regulate YAP and its effects on gastric cancer (GC) cells remain unclear. Here, we first showed that sitagliptin inhibited the proliferation of GC cells, and this inhibition was regulated by Hippo pathway. Sitagliptin phosphorylated YAP in a large tumor suppressor homolog‐dependent manner, thereby inhibiting YAP nuclear translocation, and promoted YAP cytoplasm retention. This inhibition can be blocked by adenosine 5′‐monophosphate‐activated protein kinase (AMPK). Moreover, sitagliptin could reduce the expression of tumor‐testis antigen Melanoma‐associated antigen‐A3 through YAP. In conclusion, sitagliptin may have a potential inhibitory effect on GC by AMPK/YAP/melanoma‐associated antigen‐A3 pathway.
Understanding Substrate Selectivity of Phoslactomycin Polyketide Synthase by Using Reconstituted in Vitro Systems
Authors: Geyer Kyra , Sundaram Srividhya , Sušnik Peter , Koert Ulrich , Erb Tobias J. 
Published: March 2020

AbstractPolyketide synthases (PKSs) use simple extender units to synthesize complex natural products. A fundamental question is how different extender units are site‐specifically incorporated into the growing polyketide. Here we established phoslactomycin (Pn) PKS, which incorporates malonyl‐ and ethylmalonyl‐CoA, as an in vitro model to study substrate specificity. We combined up to six Pn PKS modules with different termination sites for the controlled release of tetra‐, penta‐ and hexaketides, and challenged these systems with up to seven different extender units in competitive assays to test for the specificity of Pn modules. While malonyl‐CoA modules of Pn PKS exclusively accept their natural substrate, the ethylmalonyl‐CoA module PnC tolerates different α‐substituted derivatives, but discriminates against malonyl‐CoA. We show that the ratio of extender transacylation to hydrolysis controls incorporation in PnC, thus explaining site‐specific selectivity and promiscuity in the natural context of Pn PKS.
Pure Hydrogen and Propylene Coproduction in Catalytic Membrane Reactor‐Assisted Propane Dehydrogenation
Authors: Saidi Majid , Safaripour Maryam 
Published: March 2020

AbstractPropane dehydrogenation on a commercial Pt‐Sn/Al2O3 catalyst in a Pd‐Ag membrane reactor is considered. A mathematical model is developed to evaluate the performance of the catalytic membrane reactor for the process of propane dehydrogenation. Design and operating conditions are systematically evaluated for key performance metrics such as propane conversion, propylene selectivity, hydrogen selectivity, and hydrogen recovery under different operating conditions. The results confirm that the high performance of the membrane reactor is related to the continuous removal of hydrogen from the reaction zone to shift the reaction equilibrium towards the formation of more propylene and hydrogen.
Thermal Hysteresis and Bursting Rate in Sucrose Solutions with Antifreeze Proteins
Authors: Kiran-Yildirim Bercem , Gaukel Volker 
Published: March 2020

AbstractAntifreeze proteins (AFPs) modify the ice shape and inhibit further growth leading to thermal hysteresis (TH). Numerous studies have been performed with the addtition of AFPs to preserve frozen products but the influence of sucrose on the effects of AFPs has not been investigated as of yet. Therefore, the TH activities of type I antifreeze protein (AFP I) and antifreeze glycoprotein (AFGP) were measured as a function of concentration, type of AFPs, and also sucrose concentration. The results showed that the TH values rose with increase in concentration of AFPs and sucrose concentration. The crystals experienced shape modification and grew in the c‐axis direction in the presence of both AFPs. The bursting rate of crystals changed depending on both the concentrations of AFPs and sucrose.
Analysis of Transient Inhomogeneous Flow and Thermal Characteristics in a Drying Room via Large Eddy Simulation
Authors: Li Jin , Zhao Peng , Shi Yajun , Chang Xing , Zhang Chungang , Guo Yong , Liu Yali , Liu Chongying , Chen Yan , Yin Dachuan 
Published: March 2020

AbstractTo optimize the flow structure in a soft‐capsule drying room, the notable inhomogeneous characteristics of flow behavior and thermal feature are numerically explored. An advanced three‐dimensional numerical model is established and a verified large eddy simulation (LES) model is adopted. The results indicated that there is a highly inhomogeneous flow structure especially approaching the bilateral region of the drying room, mainly caused by the large velocity gradient whereas a relatively uniform flow structure is observed in the middle region. In the drying process, the inhomogeneous flow feature is sensitive to the increased inlet velocity and aspect ratio λ. It was found that a suitable inlet velocity and a small aspect ratio λ can provide a better drying flow environment.
Methyl Ethyl Ketone Production through an Intensified Process
Authors: Torres-Vinces Leopoldo , Contreras-Zarazua Gabriel , Huerta-Rosas Brenda , Sánchez-Ramírez Eduardo , Segovia-Hernández Juan Gabriel 
Published: March 2020

AbstractMethyl ethyl ketone (MEK) is widely used in the industry and is mainly produced from petroleum. Some works have projected MEK as a possible fuel since its performance in spark engines has overcome the performance of gasoline in certain indexes. Two intensified alternatives to produce MEK are introduced here, consisting of a reactive distillation column, an extractive distillation column, and three conventional distillation columns. The direct alternative resulted as the most promising when it was evaluated based on energy consumption, greenhouse gas emissions, and an environmental index. The obtained energy consumption for MEK production was 11.62 MJ kgMEK−1 for the entire process. Moreover, those intensified alternatives showed better performance indexes in comparison with a conventional process.
Staged Condensation of Coal Tar from the Pyrolysis of Coal in a Screw Pyrolyzer
Authors: Liu Ermei , Wang Ze , Li Songgeng , Song Wenli , Zhang Hua 
Published: March 2020

AbstractStaged condensation of coal tar was studied with a three‐staged condensation system (first stage S1, 100–300 °C; second stage S2, 30–70 °C; third stage S3, 0 °C) to perform on‐line preliminary removal of dust and fundamental fractionation of tar components. The dust and heavy components are predominantly distributed in S1. The polycyclic aromatic hydrocarbons are abundant in S1. Aliphatics and monocyclic phenols are abundant in S2, and the tar in S3 is rich in aliphatics and monocyclic aromatic hydrocarbons. With increasing S2 temperature from 30 to 70 °C, the total organics in the water phase in S2 and S3 are least at an S2 temperature of 50 °C, which is advantageous for post‐treatment of wastewater.
One‐Pot Fabrication of Crumpled N‐Doped Graphene Anchored with Cobalt for High‐Performance Lithium–Sulfur Batteries
Authors: Mao Wutao , Ma Chao , Ni Ping , Li Maolong , Ding Yiming , Zhang Shaojie , Pan Junli , Cao Fengpu , Bao Keyan 
Published: March 2020

AbstractThe commercialization of sulfur batteries is hindered by a few inherent drawbacks. In this study, crumpled N‐doped graphene anchored with cobalt (Co‐NCG) was fabricated in one pot via a sample solvothermal method and applied to lithium‐sulfur (Li−S) batteries. The crumpled structure not only gives graphene a large specific surface area and abundant pores, but also endows graphene superb stability by preventing its restacking; these features are beneficial for loading and efficient utilization of sulfur. The lone pair electrons on the nitrogen atom underwent strong chemical interactions with Li ions, which lent the Co‐NCG/S material the ability to chemically immobilize polysulfide species. Cobalt acts as an electrocatalyst in the battery and kinetically accelerates sulfur redox reactions. As a result of these multifunctional arrangements, the Co‐NCG/S cathode showed excellent capacity retention and reaction kinetics and high sulfur loading capacity.
An Efficient and Stable MoS2/Zn0.5Cd0.5S Nanocatalyst for Photocatalytic Hydrogen Evolution
Authors: Liu Wenxiang , Lu Lele , Li Qiang , Wu Boyuan , Zhang Ruizhe , Shi Wei , Cheng Peng 
Published: March 2020

AbstractPhotocatalytic hydrogen evolution by water splitting is highly important for the application of hydrogen energy and the replacement of fossil fuel by solar energy, which needs the development of efficient catalysts with long‐term catalytic stability under light irradiation in aqueous solution. Herein, Zn0.5Cd0.5S solid solution was synthesized by a metal–organic framework‐templated strategy and then loaded with MoS2 by a hydrothermal method to fabricate a MoS2/Zn0.5Cd0.5S heterojunction for photocatalytic hydrogen evolution. The composition of MoS2/Zn0.5Cd0.5S was fine‐tuned to obtain the optimized 5 wt % MoS2/Zn0.5Cd0.5S heterojunction, which showed a superior hydrogen evolution rate of 23.80 mmol h−1 g−1 and steady photocatalytic stability over 25 h. The photocatalytic performance is due to the appropriate composition and the formation of an intimate interface between MoS2 and Zn0.5Cd0.5S, which endows the photocatalyst with high light‐harvesting ability and effective separation of photogenerated carriers.
Group 6 Oxyfluoro‐Anion Salts of [XeF5]+ and [Xe2F11]+: Syntheses and Structures of [XeF5][M2O2F9] (M=Mo, W), [Xe2F11][M′OF5] (M′=Cr, Mo, W), [XeF5][HF2]⋅CrOF4, and [XeF5][WOF5]⋅XeOF4
Authors: Bortolus Mark R. , Mercier Hélène P. A. , Schrobilgen Gary J. 
Published: March 2020

AbstractThe reactions of the fluoride‐ion donor, XeF6, with the fluoride‐ion acceptors, M′OF4 (M′=Cr, Mo, W), yield [XeF5]+ and [Xe2F11]+ salts of [M′OF5]− and [M2O2F9]− (M=Mo, W). Xenon hexafluoride and MOF4 react in anhydrous hydrogen fluoride (aHF) to give equilibrium mixtures of [Xe2F11]+, [XeF5]+, [(HF)nF]−, [MOF5]−, and [M2O2F9]− from which the title salts were crystallized. The [XeF5][CrOF5] and [Xe2F11][CrOF5] salts could not be formed from mixtures of CrOF4 and XeF6 in aHF at low temperature (LT) owing to the low fluoride‐ion affinity of CrOF4, but yielded [XeF5][HF2]⋅CrOF4 instead. In contrast, MoOF4 and WOF4 are sufficiently Lewis acidic to abstract F− ion from [(HF)nF]− in aHF to give the [MOF5]− and [M2O2F9]− salts of [XeF5]+ and [Xe2F11]+. To circumvent [(HF)nF]− formation, [Xe2F11][CrOF5] was synthesized at LT in CF2ClCF2Cl solvent. The salts were characterized by LT Raman spectroscopy and LT single‐crystal X‐ray diffraction, which provided the first X‐ray crystal structure of the [CrOF5]− anion and high‐precision geometric parameters for [MOF5]− and [M2O2F9]−. Hydrolysis of [Xe2F11][WOF5] by water contaminant in HF solvent yielded [XeF5][WOF5]⋅XeOF4. Quantum‐chemical calculations were carried out for M′OF4, [M′OF5]−, [M′2O2F9]−, {[Xe2F11][CrOF5]}2, [Xe2F11][MOF5], and {[XeF5][M2O2F9]}2 to obtain their gas‐phase geometries and vibrational frequencies to aid in their vibrational mode assignments and to assess chemical bonding.
Dicht‐ und Klebstoffe auf Silikonbasis
Authors: Wolf Andreas T. 
Published: March 2020

ZusammenfassungDer Vergleich verschiedener Anwendungsgebiete von Dicht‐ und Klebstoffen auf Silikonbasis zeigt rasch, dass ihr breites Leistungs‐ und Anwendungsspektrum sowohl auf ihrer Polymerstruktur als auch auf der Formulierung beruht. Diese synthetischen Werkstoffe sind gekennzeichnet durch einen großen Temperatureinsatzbereich, sehr gute elektrische Eigenschaften, hohe Flexibilität, exzellente UV‐Beständigkeit, gute chemische Beständigkeit, hervorragende Witterungsbeständigkeit, geringe Brennbarkeit, keine oder nur sehr geringe Toxizität, sowie einfache Verarbeitung und Anwendung. Diese inhärenten Eigenschaften der Silikone, die auf der besonderen Natur der Siloxanbindung beruhen, können durch Variation der Produktformulierung, zum Beispiel durch den Zusatz von Füllstoffen oder anderen chemischen Additiven, noch verändert werden. Hierdurch lassen sich spezifische Funktionen und Eigenschaften verbessern oder hinzufügen. Ebenso lassen sich über die Formulierung des Kleb‐ oder Dichtstoffes dessen rheologische und mechanische Eigenschaften einstellen sowie die Hafteigenschaften beeinflussen.
Expedient Synthesis of Ketones viaN‐Heterocyclic Carbene/Nickel‐Catalyzed Redox‐Economical Coupling of Alcohols and Alkynes†
Authors: Li Yu‐Qing , Li Feng , Shi Shi‐Liang 
Published: March 2020

Summary of main observation and conclusionAn N‐heterocyclic carbene/nickel‐catalyzed direct coupling of alcohols and internal alkynes to form α‐branched ketones has been developed. This methodology provides a new approach to afford branched ketones, which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes. This redox‐neutral and redox‐economical coupling is free from any oxidative or reductive additives as well as stoichiometric byproducts. These reactions convert both benzylic and aliphatic alcohols and alkynes, two basic feedstock chemicals, into various α‐branched ketones in a single chemical step.
Pd‐Catalyzed Asymmetric Intramolecular Arylative Dearomatization of para‐Aminophenols†
Authors: Xu Ren‐Qi , Yang Ping , Zheng Chao , You Shu‐Li 
Published: March 2020

Summary of main observation and conclusionAsymmetric arylative dearomatization reactions of para‐aminophenols are realized by a Pd‐catalyst consisting of a TADDOL (α,α,α',α'‐tetraaryl‐2,2‐disubstituted 1,3‐dioxolane‐4,5‐dimethanol)‐derived chiral phosphoramidite ligand. The tetracyclic products bearing the key skeleton of Erythrina alkaloids are afforded in reasonable yields (up to 73%) with good to excellent enantioselectivity (up to 97% ee). Concise total synthesis of (–)‐3‐demethoxyerythratidinone is achieved by employing this method as the key step.
Longitudinal pain and pain interference in long‐term survivors of childhood cancer: A report from the Childhood Cancer Survivor Study
Authors: Karlson Cynthia W. , Alberts Nicole M. , Liu Wei , Brinkman Tara M. , Annett Robert D. , Mulrooney Daniel A. , Schulte Fiona , Leisenring Wendy M. , Gibson Todd M. , Howell Rebecca M. , Srivastava Deokumar , Oeffinger Kevin C. , Robison Leslie L. , Armstrong Gregory T. , Zeltzer Lonnie K. , Krull Kevin R. 
Published: March 2020

BackgroundThe objective of this study was to characterize the prevalence and risk of pain, pain interference, and recurrent pain in adult survivors of childhood cancer in comparison with siblings.MethodsThis study analyzed longitudinal data from survivors (n = 10,012; 48.7% female; median age, 31 years [range, 17‐57 years]; median time since diagnosis, 23 years) and siblings (n = 3173) from the Childhood Cancer Survivor Study. Survivors were diagnosed between 1970 and 1986 at 1 of 26 participating sites. Associations between risk factors (demographics, cancer‐related factors, and psychological symptoms) and pain, pain interference, and recurrent pain (5 years apart) were assessed with multinomial logistic regression. Path analyses examined cross‐sectional associations between risk factors and pain outcomes.ResultsTwenty‐nine percent of survivors reported moderate to severe pain, 20% reported moderate to extreme pain interference, and 9% reported moderate to severe recurrent pain. Female sex, a sarcoma/bone tumor diagnosis, and severe/life‐threatening chronic medical conditions were associated with recurrent pain. Depression and anxiety were associated with increased risk for all pain outcomes. Poor vitality mediated the effects of anxiety on high pain and pain interference (root mean square error of approximation, 0.002).ConclusionsA large proportion of adult survivors report moderate to severe pain and pain interference more than 20 years after their diagnosis. Increased screening and early intervention for pain interference and recurrent pain are warranted.
An asynchronous computation architecture for enhancing the performance of the Weather Research and Forecasting model
Authors: Bayá Rodrigo , Pedemonte Martín , Gutiérrez Arce Alejandro , Ezzatti Pablo 
Published: March 2020

SummaryThe Weather Research and Forecasting (WRF) model does not usually show an adequate scalability for small‐sized domains in large computing platforms. With this in mind, we propose a novel asynchronous software architecture for the WRF model that decouples the calculation of the solar radiation from the rest of the model. The experimental evaluation was conducted on real‐world data for forecasting the photovoltaic energy fed into the electrical grid of Uruguay by twelve solar power plants. The experimental results show that the proposed architecture can make a better use of the hardware resources available on the computing platform, reducing the total runtime of the WRF while maintaining the numerical accuracy.
A class‐AB flipped voltage follower cell with high symmetrical slew rate and high current sourcing/sinking capability
Authors: Jindal Caffey , Pandey Rishikesh 
Published: March 2020

SummaryThe paper presents a class‐AB flipped voltage follower (FVF) cell based on quasi‐floating gate and bulk‐driven techniques. The quasi‐floating gate technique is used to increase the current sinking capability, whereas the bulk‐driven technique is used to enhance the current sourcing capability by reducing the threshold voltage. Using these two techniques, the proposed class‐ AB FVF cell offers high current sinking and sourcing capabilities. Also, it provides high symmetrical slew rate without any additional circuitry. The physical layout of the proposed class‐ AB FVF cell has been designed in Cadence Virtuoso Layout XL editor using BSIM3v3 180‐nm CMOS technology, and post‐layout simulation results have been presented to validate its performance. The corner analysis of the proposed class‐ AB FVF cell has also been performed with temperature and supply voltage as design variables to show its performance under extreme conditions.