bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselective Bioamination of Aromatic Alkanes Using Ammonia: A Multienzymatic Cascade Approach
Authors: Wang Hui , Zheng Yu‐Cong , Chen Fei‐Fei , Xu Jian‐He , Yu Hui‐Lei 
Published: January 2020

AbstractChiral amines are common drug building blocks and important active pharmaceutical ingredients. Preparing these functionalized compounds from simple materials, such as alkanes, is of great interest. We recently developed an artificial bioamination cascade for the C−H amination of cyclic alkanes by combining P450 monooxygenase, alcohol dehydrogenase, and amine dehydrogenase. Herein, this system has been extended to the synthesis of chiral aromatic amines. In the first hydroxylation step, process optimization increased the conversion to 77 %. Two stereoselectively complementary alcohol dehydrogenases and an amine dehydrogenase were selected for the bioconversion of aromatic hydrocarbons to amines. The amination reaction was optimized with respect to cofactor addition and enzyme dosage. Isopropanol was added to decrease ketone intermediate accumulation in the amination step, which further enhanced the overall conversion. This cascade system converted a panel of hydrocarbon substrates into the corresponding amines with excellent optical purity (>99 % ee) and moderate conversion ratios (13–53 %).
Molybdenum Disulfide Based Nanomaterials for Rechargeable Batteries
Authors: Wu Junxiong , Ciucci Francesco , Kim Jang‐Kyo 
Published: January 2020

AbstractThe rapid development of electrochemical energy storage systems requires new electrode materials with high performance. As a two‐dimensional material, molybdenum disulfide (MoS2) has attracted increasing interest in energy storage applications due to its layered structure, tunable physical and chemical properties, and high capacity. In this review, the atomic structures and properties of different phases of MoS2 are first introduced. Then, typical synthetic methods for MoS2 and MoS2‐based composites are presented. Furthermore, the recent progress in the design of diverse MoS2‐based micro/nanostructures for rechargeable batteries, including lithium‐ion, lithium‐sulfur, sodium‐ion, potassium‐ion, and multivalent‐ion batteries, is overviewed. Additionally, the roles of advanced in situ/operando techniques and theoretical calculations in elucidating fundamental insights into the structural and electrochemical processes taking place in these materials during battery operation are illustrated. Finally, a perspective is given on how the properties of MoS2‐based electrode materials are further improved and how they can find widespread application in the next‐generation electrochemical energy‐storage systems.
Exploring the Biocatalytic Potential of Fe/α‐Ketoglutarate‐Dependent Halogenases
Authors: Voss Moritz , Honda Malca Sumire , Buller Rebecca 
Published: January 2020

AbstractFreestanding Fe/α‐ketoglutarate‐dependent halogenases are oxidoreductases that catalyze the installation of halogen atoms into unactivated sp3‐hybridized carbon centers with high stereo‐ and regioselectivity. Since their discovery in 2014, a small number of indole alkaloid and amino acid halogenases have been identified and characterized. First enzyme engineering examples suggest that the accessible substrate range of these enzymes may be expanded through the use of rational enzyme design and directed evolution. Structural investigations of non‐heme iron halogenases acting on freestanding as well as tethered substrates are beginning to inform about the principles of the underlying halogenation mechanism.
Towards the Molecular Design of Spin‐Crossover Complexes of 2,6‐Bis(pyrazol‐3‐yl)pyridines
Authors: Nikovskiy Igor , Polezhaev Alexander , Novikov Valentin , Aleshin Dmitry , Pavlov Alexander , Saffiulina Elnara , Aysin Rinat , Dorovatovskii Pavel , Nodaraki Lydia , Tuna Floriana , Nelyubina Yulia 
Published: January 2020

AbstractThe molecular design of spin‐crossover complexes relies on controlling the spin state of a transition metal ion by proper chemical modifications of the ligands. Herein, the first N,N’‐disubstituted 2,6‐bis(pyrazol‐3‐yl)pyridines (3‐bpp) are reported that, against the common wisdom, induce a spin‐crossover in otherwise high‐spin iron(II) complexes by increasing the steric demand of a bulky substituent, an ortho‐functionalized phenyl group. As N,N’‐disubstituted 3‐bpp complexes have no pendant NH groups that make their spin state extremely sensitive to the environment, the proposed ligand design, which may be applicable to isomeric 1‐bpp or other families of popular bi‐, tri‐ and higher denticity ligands, opens the way for their molecular design as spin‐crossover compounds for future breakthrough applications.
Preparation and evaluation of biselector bonded‐type multifunctional chiral stationary phase based on dialdehyde cellulose and 6‐monodeoxy‐6‐monoamino‐β‐cyclodextrine derivatives
Authors: Gao Jie , Quan Kaijun , Li Hui , Li Zhan , Zhao Liang , Qiu Hongdeng 
Published: January 2020

AbstractA novel biselector bonded‐type multifunctional chiral stationary phase (MCSP) was prepared by covalently crosslinking dialdehyde cellulose (DAC) with 6‐monodeoxy‐6‐monoamino‐β‐cyclodextrine (CD) via Schiff base reaction. The biselector bonded‐type MCSP had good chiral and achiral chromatographic performance in normal phase (NP) and reversed phase (RP) modes. Seven and eight enantiomers were successfully separated on the prepared biselector bonded‐type MCSP in NP and RP modes, respectively. The biselector bonded‐type MCSP showed enhanced chiral resolution ability compared with single selector chiral stationary phases due to the simultaneous introduction of DAC and 6‐monodeoxy‐6‐monoamino‐β‐CD on the surface of silica gel. Aromatic compounds including polycyclic aromatic hydrocarbons, anilines, phenols, phenylates, and aromatic acids were choosed as analytes to investigate the achiral chromatographic performance of the biselector bonded‐type MCSP in NP and RP modes. Chromatographic evaluation results showed that the above aromatic compounds were essentially capable of achieving baseline separation by hydrophobic interaction, π‐π interaction, and π‐π electron‐donor‐acceptor interaction. Moreover, the host‐guest inclusion effect of 6‐monodeoxy‐6‐monoamino‐β‐CD and the multiple interactions made the biselector bonded‐type MCSP have good steric selectivity. The preparation method of the biselector bonded‐type MCSP was simple and provided a new idea and strategy for the preparation of the subsequent novel biselector MCSP.
Chiral combinatorial preparation and biological evaluation of unique ceramides for inhibition of sphingomyelin synthase
Authors: Koolath Sajeer , Murai Yuta , Suga Yoshiko , Monde Kenji 
Published: January 2020

AbstractEnantiomers or diastereomers of chiral bioactive compounds often exhibit different biological and toxicological properties. Here, we report the efficient synthesis of four stereoisomers of sphingosine and derivatization of unique chiral ceramides through a combinatorial chemistry by solid‐phase activated resin ester. In addition, to test the effectivity of stereochemistry of ceramide, we demonstrated a cell‐based assay of sphingomyelin synthase inhibition in the presence ofchiral unique ceramides, which suggested that libraries of this sort will be a rich source of biologically active synthetic molecules.
Effect of chemical structure of benzofuran derivatives and reaction conditions on enantioselective properties of Aureobasidium pullulans microorganism contained in Boni Protect antifungal agent
Authors: Kołodziejska Renata , Studzińska Renata , Tafelska‐Kaczmarek Agnieszka , Pawluk Hanna , Stasiak Bartosz , Kwit Marcin , Woźniak Alina 
Published: January 2020

AbstractBioorganic asymmetric reduction of carbonyl compounds is one of the most important fundamental and practical reactions for producing chiral alcohols. The stereoselective bioreduction of prochiral ketones of benzofuran derivatives in the presence of yeast‐like fungus Aureobasidium pullulans contained in the antifungal Boni Protect agent was studied. Biotransformations were carried out under moderate conditions in an aqueous and two‐phase system and without multiplication of the bioreagent. Despite similar chemical structure, each of the used ketone has been reduced with varying efficiency and selectivity. One of the reasons for these results is the presence of a whole set of oxidoreductases in A. pullulans cells that are sensitive to the smallest changes in the structure of prochiral substrate. The unsymmetrical methyl ketones were biotransformed with the highest selectivity. Aureobasidium pullulans microorganism is less effective in the reduction of unsymmetrical halomethyl ketones. The presence of a heteroatom in the alkyl group significantly decreases the selectivity of the process. Finally, as a result of the preferred hydride ion transfer from the dihydropyridine ring of the cofactor to the carbonyl double bond on the re side, secondary alcohols of the S and R configuration were obtained with moderate to high enantioselectivity (55‐99%).
A mode transformation algorithm based on traffic prediction in virtual multi‐OLT PON
Authors: Zhan Nianfei , Gan Chaoqin , Lin Wei , Guo Yaqin , Liu Pengfei 
Published: January 2020

SummaryIn this paper, a mode transformation algorithm based on traffic prediction in virtual multiple optical line terminal (OLT) passive optical network (PON) is proposed. By proposing exponential smoothing algorithm based on weight update (WU‐ESA), user traffic is predicted well. WU‐ESA is a combination of two algorithms: exponential smoothing algorithm (ESA) and genetic algorithm (GA). The weight in ESA is optimized by GA based on real‐number encoding. By setting two periods, GA part and ESA part can be separated effectively. By presenting elastic packing algorithm (EPA), the load balance problem in virtual multi‐OLT PON is solved. EPA is implemented based on WU‐ESA. By the simulation and analysis, the effectiveness of the proposed algorithms is demonstrated. Compared with traditional mode transformation algorithm, EPA shows good performances in delay, throughput, and packet loss. Compared with traditional mode transformation algorithm, the EPA makes the packet loss decrease by at least 5% when the system load is greater than 0.9. Meanwhile, the delay of the two subsystems can be kept at a relatively balanced level by the implement of EPA. For throughput, the use of EPA improves the throughput by 20% when the system load is high.
Oversight of Right‐to‐Try and Expanded Access Requests for Off‐Trial Access to Investigational Drugs
Authors: Chapman Carolyn Riley , Eckman Jared , Bateman‐House Alison S. 
Published: January 2020

ABSTRACTFor decades, the U.S. Food and Drug Administration (FDA) has provided an “expanded access” pathway that allows patients who meet qualifying conditions to gain access outside a clinical trial to an investigational medical product being tested to see if it is safe and effective for a specific use. The Right to Try (RTT) Act, enacted in 2018, created a second mechanism for off‐trial, or non‐trial, access to investigational drugs. In contrast to the expanded access pathway, the federal RTT pathway does not require the involvement of the FDA or an institutional review board (IRB). Given that physicians, drug manufacturers, and medical institutions now have a choice whether to assist individual patients through the expanded access or the federal RTT pathway, we review the differences between these options and discuss the benefits and burdens of IRB involvement in requests to access interventions through the pathways. We also suggest ways in which IRB oversight may be further improved.
Larval dispersal in a changing ocean with an emphasis on upwelling regions
Authors: Bashevkin Samuel M. , Dibble Connor D. , Dunn Robert P. , Hollarsmith Jordan A. , Ng Gabriel , Satterthwaite Erin V. , Morgan Steven G. 
Published: January 2020

AbstractDispersal of benthic species in the sea is mediated primarily through small, vulnerable larvae that must survive minutes to months as members of the plankton community while being transported by strong, dynamic currents. As climate change alters ocean conditions, the dispersal of these larvae will be affected, with pervasive ecological and evolutionary consequences. We review the impacts of oceanic changes on larval transport, physiology, and behavior. We then discuss the implications for population connectivity and recruitment and evaluate life history strategies that will affect susceptibility to the effects of climate change on their dispersal patterns, with implications for understanding selective regimes in a future ocean. We find that physical oceanographic changes will impact dispersal by transporting larvae in different directions or inhibiting their movements while changing environmental factors, such as temperature, pH, salinity, oxygen, ultraviolet radiation, and turbidity, will affect the survival of larvae and alter their behavior. Reduced dispersal distance may make local adaptation more likely in well‐connected populations with high genetic variation while reduced dispersal success will lower recruitment with implications for fishery stocks. Increased dispersal may spur adaptation by increasing genetic diversity among previously disconnected populations as well as increasing the likelihood of range expansions. We hypothesize that species with planktotrophic (feeding), calcifying, or weakly swimming larvae with specialized adult habitats will be most affected by climate change. We also propose that the adaptive value of retentive larval behaviors may decrease where transport trajectories follow changing climate envelopes and increase where transport trajectories drive larvae toward increasingly unsuitable conditions. Our holistic framework, combined with knowledge of regional ocean conditions and larval traits, can be used to produce powerful predictions of expected impacts on larval dispersal as well as the consequences for connectivity, range expansion, or recruitment. Based on our findings, we recommend that future studies take a holistic view of dispersal incorporating biological and oceanographic impacts of climate change rather than solely focusing on oceanography or physiology. Genetic and paleontological techniques can be used to examine evolutionary impacts of altered dispersal in a future ocean, while museum collections and expedition records can inform modern‐day range shifts.
Earlier fall precipitation and low severity fire impacts on cheatgrass and sagebrush establishment
Authors: Bishop Tara B. B. , Nusink Baylie C. , Lee Molinari Rebecca , Taylor Justin B. , St. Clair Samuel B. 
Published: January 2020

AbstractIn arid and semiarid ecosystems, invasion by exotic grasses may be driving state changes in vegetation defined by losses of native shrub communities. Changes in wildfire regimes and fall precipitation timing related to climate change may promote fluctuations in resource availability that reinforces invasion and state changes in vegetation. The objective of this study was to investigate how earlier fall precipitation timing and fire affected the germination, establishment, and growth of the dominant native shrub Wyoming big sagebrush (Artemisia tridentatasubsp.wyomingensis), and one of the most problematic invaders, cheatgrass (Bromus tectorumL.) in the Great Basin. We extracted soil cores from Rush Valley, Utah (UT),USA, on the eastern side of the Great Basin ecoregion and placed them in a common garden in Provo,UT, and planted seeds of sagebrush and cheatgrass in individual cores. We measured the response of sagebrush and cheatgrass to experimental fire and two fall precipitation timing pulses in a full factorial design. Water was added for two weeks in early September (early fall treatment) and mid‐October (late fall treatment). We measured seedling emergence, plant height, biomass, density, seed production, and survival. Early fall precipitation did not significantly affect the amount of cheatgrass or sagebrush seedling emergence. Early fall precipitation significantly increased cheatgrass density, height, biomass, and seed production, and sagebrush height and biomass, but not density. Surprisingly, cheatgrass did not respond positively to fire. In contrast, fire increased sagebrush density (twofold) and survival. These findings indicate that fire can have positive impacts on sagebrush establishment. The data suggest that projected increases in fall moisture in the Great Basin due to climate change are likely to have positive impacts on both cheatgrass and sagebrush. However, additional studies are needed to identify how fall precipitation timing and fire might impact competitive interactions between sagebrush and cheatgrass and the bearing on invasion success at influencing state changes in the Great Basin.
H2FPEF score for predicting future heart failure in stable outpatients with cardiovascular risk factors
Authors: Suzuki Satoru , Kaikita Koichi , Yamamoto Eiichiro , Sueta Daisuke , Yamamoto Masahiro , Ishii Masanobu , Ito Miwa , Fujisue Koichiro , Kanazawa Hisanori , Araki Satoshi , Arima Yuichiro , Takashio Seiji , Usuku Hiroki , Nakamura Taishi , Sakamoto Kenji , Izumiya Yasuhiro , Soejima Hirofumi , Kawano Hiroaki , Jinnouchi Hideaki , Matsui Kunihiko , Tsujita Kenichi 
Published: January 2020

AbstractAimsThe prediction of future heart failure (HF) in stable outpatients is often difficult for general practitioners and cardiologists. Recently, the H2FPEF score (0–9 points) has been proposed for the discrimination of HF with preserved ejection fraction from non‐cardiac causes of dyspnoea. The six clinical and echocardiographic variables that constitute the H2FPEF score include the following: (i) obesity (H); (ii) the use of ≥2 antihypertensive drugs (H); (iii) atrial fibrillation (F); (iv) pulmonary hypertension (P); (v) an age > 60 years (E); and (vi) E/e' > 9 (F). We performed an external validation study that investigated whether the H2FPEF score could predict future HF‐related events in stable outpatients with cardiovascular risk factor(s) in Japan.Methods and resultsIn this prospective cohort study, after exclusion of 195 from 551 consecutive, stable Japanese outpatients with at least one cardiovascular risk factor who were enrolled between September 2010 and July 2013, the remaining 356 outpatients (171 men, 185 women, mean age 73.2 years) were eligible for the analysis. We calculated the H2FPEF score (0–9 points), and followed up the patients for an average of 517 days. In all of the 356 patients, the mean H2FPEF score was 3.1 ± 1.8, and 15 developed HF‐related events during the follow‐up period, including cardiovascular death (n = 2) and hospitalization for HF decompensation (n = 13). Multivariate Cox proportional hazards analysis showed that the H2FPEF score was an independent predictor of future HF‐related events (P < 0.001 for all three models). Kaplan–Meier survival curves showed a significantly higher probability of HF‐related events in the outpatients with a high H2FPEF score (P < 0.001). In receiver operating characteristic (ROC) curve analysis, the H2FPEF score was significantly associated with the occurrence of future HF‐related events (P < 0.001). In ROC curve analysis, the sensitivity, specificity, and positive likelihood ratio of a H2FPEF score of 7 points to predict HF‐related events were 47%, 96%, and 11.4%, respectively.ConclusionsThe H2FPEF score could provide useful information for future HF‐related events in stable outpatients with cardiovascular risk factor(s) in Japan.
Stroke risk and atrial mechanical dysfunction in cardiac amyloidosis
Authors: Ballantyne Brennan , Manian Usha , Sheyin Olusegun , Davey Ryan , De Sabe 
Published: January 2020

AbstractAmyloidosis is associated with poor prognosis, and patients with cardiac involvement have especially poor outcomes. Cardiac amyloidosis leads to higher rates of atrial arrhythmia and an increased risk of intracardiac thrombus formation. However, atrial mechanical dysfunction due to protein deposition in amyloidosis may lead to thrombus formation in the absence of atrial arrhythmia. We present a 42‐year‐old male patient with familial transthyretin amyloidosis who suffered an embolic stroke that originated from a left atrial appendage thrombus in the absence of any documented atrial fibrillation. This case highlights atrial mechanical dysfunction in patients with cardiac amyloidosis and the need to better stratify thrombotic risk in this population with integration of echocardiographic parameters and transesophageal echocardiography.
Pd/CNT Catalysts for Glycerol Electro‐oxidation: Effect of Pd Loading on Production of Valuable Chemical Products
Authors: Ahmad Muhammad Sheraz , Cheng Chin Kui , Kumar Ravinder , Singh Sharanjit , Saeed Khater Ahmed , Ong Huei Ruey , Abdullah Hamidah , Khan Maksudur Rahman 
Published: January 2020

AbstractGlycerol (C3H8O3), a waste product of biodiesel, is considered as a suitable substrate for electro‐oxidation process to generate high value‐added products. A suitable active catalyst could improve the yield of desirable organic compounds from electro‐oxidation of glycerol. In this work, palladium nanoparticles supported over activated multi‐walled carbon nanotubes (MWCNTs) with varying loadings of 5 %–40 % were prepared using chemical reduction method and used to study their potential for electro‐oxidation of glycerol to produce various high value‐added products. The catalysts were characterized by different physicochemical methods, such as X‐ray diffraction (XRD), N2 adsorption‐desorption, and Transmission electron microscopy (TEM), whereas the electro‐oxidation activity of the catalysts was analysed using cyclic voltammetry (CV) and chronoamperometry (CA), and the products were identified by high performance liquid chromatography (HPLC). The electrochemical surface area (SESA) and mass activity (MA) were increased from 176.98 m2 g−1 to 282.29 m2 g−1 and 12.22 mA mg−1 to 49.53 mA mg−1 by increasing the Pd‐loading from 5 % to 20 %, respectively. While the further increase to 40 % Pd loading, the SESA and MA values decreased to 231.45 m2 g−1 and 47.63 mA mg−1respectively. The results found that the optimum 20 % Pd‐loading showed the excellent electrochemical properties due to uniform distribution of Pd‐metal particles over MWCNTs. High performance liquid chromatography (HPLC) showed the tartronic acid, glyceric acid and glyceraldehyde as dominant products. Mechanism of the reaction has also been proposed based on product distribution.