bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversible Functionalization of Clickable Polyacrylamide Gels with Protein and Graft Copolymers
Authors: Neira Hector D. , Jeeawoody Shaheen , Herr Amy E. 
Published: September 2020

AbstractModular strategies to fabricate gels with tailorable chemical functionalities are relevant to applications spanning from biomedicine to analytical chemistry. Here, the properties of clickable poly(acrylamide‐co‐propargyl acrylate) (pAPA) hydrogels are modified via sequential in‐gel copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) reactions. After optimization, in‐gel CuAAC reactions proceed with rate constants of ≈0.003 s−1, ensuring uniform modifications for gels <200 μm thick. Using the modular functionalization approach and a cleavable disulfide linker, pAPA gels are modified with benzophenone (BP) and acrylate groups. BP groups allow gel functionalization with unmodified proteins using photoactivation. Acrylate groups enable copolymer grafting onto the gels. To release the functionalized unit, pAPA gels are treated with disulfide reducing agents, triggering ≈50% release of immobilized protein and grafted copolymers. The molecular mass of grafted copolymers (≈6.2 kDa) is estimated by monitoring the release process, expanding the tools available to characterize copolymers grafted onto hydrogels. Investigation of the efficiency of in‐gel CuAAC reactions revealed limitations of the sequential modification approach, as well as guidelines to convert the singly functional pAPA gels into gels with three distinct functionalities. Taken together, this modular framework to engineer multifunctional hydrogels benefits application of hydrogels in drug delivery, tissue engineering, and separation science.
MoS2/Polymer Heterostructures Enabling Stable Resistive Switching and Multistate Randomness
Authors: Chai Jianwei , Tong Shiwun , Li Changjian , Manzano Carlos , Li Bing , Liu Yanpeng , Lin Ming , Wong Laimun , Cheng Jianwei , Wu Jing , Lau Aaron , Xie Qidong , Pennycook Stephen J. , Medina Henry , Yang Ming , Wang Shijie , Chi Dongzhi 
Published: September 2020

AbstractResistive random‐access memories (ReRAMs) based on transition metal dichalcogenide layers are promising physical sources for random number generation (RNG). However, most ReRAM devices undergo performance degradation from cycle to cycle, which makes preserving a normal probability distribution during operation a challenging task. Here, ReRAM devices with excellent stability are reported by using a MoS2/polymer heterostructure as active layer. The stability enhancement manifests in outstanding cumulative probabilities for both high‐ and low‐resistivity states of the memory cells. Moreover, the intrinsic values of the high‐resistivity state are found to be an excellent source of randomness as suggested by a Chi‐square test. It is demonstrated that one of these cells alone can generate ten distinct random states, in contrast to the four conventional binary cells that would be required for an equivalent number of states. This work unravels a scalable interface engineering process for the production of high‐performance ReRAM devices, and sheds light on their promising application as reliable RNGs for enhanced cybersecurity in the big data era.
Blocking Ion Migration Stabilizes the High Thermoelectric Performance in Cu2Se Composites
Authors: Yang Dongwang , Su Xianli , Li Jun , Bai Hui , Wang Shanyu , Li Zhi , Tang Hao , Tang Kechen , Luo Tingting , Yan Yonggao , Wu Jinsong , Yang Jihui , Zhang Qingjie , Uher Ctirad , Kanatzidis Mercouri G. , Tang Xinfeng 
Published: September 2020

AbstractThe applications of mixed ionic–electronic conductors are limited due to phase instability under a high direct current and large temperature difference. Here, it is shown that Cu2Se is stabilized through regulating the behaviors of Cu+ ions and electrons in a Schottky heterojunction between the Cu2Se host matrix and in‐situ‐formed BiCuSeO nanoparticles. The accumulation of Cu+ ions via an ionic capacitive effect at the Schottky junction under the direct current modifies the space‐charge distribution in the electric double layer, which blocks the long‐range migration of Cu+ and produces a drastic reduction of Cu+ ion migration by nearly two orders of magnitude. Moreover, this heterojunction impedes electrons transferring from BiCuSeO to Cu2Se, obstructing the reduction reaction of Cu+ into Cu metal at the interface and hence stabilizes the β‐Cu2Se phase. Furthermore, incorporation of BiCuSeO in Cu2Se optimizes the carrier concentration and intensifies phonon scattering, contributing to the peak figure of merit ZT value of ≈2.7 at 973 K and high average ZT value of ≈1.5 between 400 and 973 K for the Cu2Se/BiCuSeO composites. This discovery provides a new avenue for stabilizing mixed ionic–electronic conduction thermoelectrics, and gives fresh insights into controlling ion migration in these ionic‐transport‐dominated materials.
Reduced Graphene Oxide‐Encapsulated Microfiber Patterns Enable Controllable Formation of Neuronal‐Like Networks
Authors: Wang Juan , Wang Haoyu , Mo Xiumei , Wang Hongjun 
Published: September 2020

AbstractScaffold‐guided formation of neuronal‐like networks, especially under electrical stimulation, can be an appealing avenue toward functional restoration of injured nervous systems. Here, 3D conductive scaffolds are fabricated based on printed microfiber constructs using near‐field electrostatic printing (NFEP) and graphene oxide (GO) coating. Various microfiber patterns are obtained from poly(l‐lactic acid‐co‐caprolactone) (PLCL) using NFEP and complexity is achieved via modulating the fiber overlay angles (45°, 60°, 75°, 90°), fiber diameters (15 to 148 µm), and fiber spatial organization (spider web and tubular structure). Upon coating GO onto PLCL microfibers via a layer‐by‐layer (L‐b‐L) assembly technique and in situ reduction into reduced GO (rGO), the obtained conductive scaffolds, with 25–50 layers of rGO, demonstrate superior conductivity (≈0.95 S cm−1) and capability of inducing neuronal‐like network formation along the conductive microfibers under electrical stimulation (100–150 mV cm−1). Both electric field (0–150 mV cm−1) and microfiber diameter (17–150 µm) affect neurite outgrowth (PC‐12 cells and primary mouse hippocampal neurons) and the formation of orientated neuronal‐like networks. With further demonstration of such guidance to neuronal cells, these conductive scaffolds may see versatile applications in nerve regeneration and neural engineering.
One‐Step Synthesis of Charge‐Transfer Salt Nanosensors on Microelectrode Patterns
Authors: Yu Xuecheng , Kilani Mohamed , Siddiqui Abdurrafay , Mao Guangzhao 
Published: September 2020

AbstractDespite extensive research on nanowires and nanosensors, the lack of manufacturing methods limits nanosensor commercialization. Here a new way of making nanowire sensors is demonstrated. Nanowire crystals of charge‐transfer salt, tetrathiafulvalene bromide or (TTF)Br, are electrochemically deposited across lines of microelectrodes made by photolithography to complete the sensor circuitry. A novel concept is the direct synthesis of nanowires on sensor substrates using pre‐existing patterns to direct the nanowire nucleation and crystallization. The gas sensing capability of the nanowire assembly is demonstrated for the detection of ammonia at a concentration range of 1–100 ppm by measuring the changes in its electrical impedance. The selectivity toward ammonia against water vapor, one of the most persistent challenges for wide adoption of nanosensors for gas detection, can be tuned by (TTF)Br nanowire chemical composition during synthesis. This work demonstrates a proof of concept toward scalable manufacturing of nanosensor devices via one‐step, substrate‐directed nucleation and crystallization.
Reprogramming Epoxide Hydrolase to Improve Enantioconvergence in Hydrolysis of Styrene Oxide Scaffolds
Authors: Li Fu‐Long , Qiu Yan‐Yan , Zheng Yu‐Cong , Chen Fei‐Fei , Kong Xu–Dong , Xu Jian‐He , Yu Hui‐Lei 
Published: September 2020

AbstractEnantioconvergent hydrolysis by epoxide hydrolase is a promising method for the synthesis of important vicinal diols. However, the poor regioselectivity of the naturally occurring enzymes results in low enantioconvergence in the enzymatic hydrolysis of styrene oxides. Herein, modulated residue No. 263 was redesigned based on structural information and a smart variant library was constructed by site‐directed modification using an “optimized amino acid alphabet” to improve the regioselectivity of epoxide hydrolase from Vigna radiata (VrEH2). The regioselectivity coefficient (r) of variant M263Q for the R‐isomer of meta‐substituted styrene oxides was improved 40–63‐fold, and variant M263V also exhibited higher regioselectivity towards the R‐isomer of para‐substituted styrene oxides compared with the wild type, which resulted in improved enantioconvergence in hydrolysis of styrene oxide scaffolds. Structural insight showed the crucial role of residue No. 263 in modulating the substrate binding conformation by altering the binding surroundings. Furthermore, increased differences in the attacking distance between nucleophilic residue Asp101 and the two carbon atoms of the epoxide ring provided evidence for improved regioselectivity. Several high‐value vicinal diols were readily synthesized (>88% yield, 90%–98% ee) by enantioconvergent hydrolysis using the reprogrammed variants. These findings provide a successful strategy for enhancing the enantioconvergence of native epoxide hydrolases through key single‐site mutation and more powerful enzyme tools for the enantioconvergent hydrolysis of styrene oxide scaffolds into single (R)‐enantiomers of chiral vicinal diols.magnified image
Cucurbit[6]uril‐Derived Nitrogen‐Doped Hierarchical Porous Carbon Confined in Graphene Network for Potassium‐Ion Hybrid Capacitors
Authors: Qiu Daping , Guan Jingyu , Li Min , Kang Cuihua , Wei Jinying , Wang Feng , Yang Ru 
Published: September 2020

AbstractPotassium‐ion hybrid capacitors (PIHCs) have attracted tremendous attention because their energy density is comparable to that of lithium‐ion batteries, whose power density and cyclability are similar to those of supercapacitors. Herein, a pomegranate‐like graphene‐confined cucurbit[6]uril‐derived nitrogen‐doped carbon (CBC@G) with ultra‐high nitrogen‐doping level (15.5 at%) and unique supermesopore‐macropores interconnected graphene network is synthesized. The carbonization mechanism of cucurbit[6]uril is verified by an in situ TG‐IR technology. In a K half‐cell configuration, CBC@G anode demonstrates a superior reversible capacity (349.1 mA h g−1 at 0.1 C) as well as outstanding rate capability and cyclability. Moreover, systematic in situ/ex situ characterizations, and theory calculations are carried out to reveal the origin of the superior electrochemical performances of CBC@G. Consequently, PIHCs constructed with CBC@G anode and KOH‐activated cucurbit[6]uril‐derived nitrogen‐doped carbon cathode demonstrate ultra‐high energy/power density (172 Wh kg−1/22 kW kg−1) and extraordinary cyclability (81.5% capacity retention for 5000 cycles at 5 A g−1). This work opens up a new application field for cucurbit[6]uril and provides an alternative avenue for the exploitation of high‐performance PIHCs.
Alterations of the Human Gut Microbiome in Chronic Kidney Disease
Authors: Ren Zhigang , Fan Yajuan , Li Ang , Shen Quanquan , Wu Jian , Ren Lingyan , Lu Haifeng , Ding Suying , Ren Hongyan , Liu Chao , Liu Wenli , Gao Dan , Wu Zhongwen , Guo Shiyuan , Wu Ge , Liu Zhangsuo , Yu Zujiang , Li Lanjuan 
Published: September 2020

AbstractGut microbiota make up the largest microecosystem in the human body and are closely related to chronic metabolic diseases. Herein, 520 fecal samples are collected from different regions of China, the gut microbiome in chronic kidney disease (CKD) is characterized, and CKD classifiers based on microbial markers are constructed. Compared with healthy controls (HC, n = 210), gut microbial diversity is significantly decreased in CKD (n = 110), and the microbial community is remarkably distinguished from HC. Genera Klebsiella and Enterobacteriaceae are enriched, while Blautia and Roseburia are reduced in CKD. Fifty predicted microbial functions including tryptophan and phenylalanine metabolisms increase, while 36 functions including arginine and proline metabolisms decrease in CKD. Notably, five optimal microbial markers are identified using the random forest model. The area under the curve (AUC) reaches 0.9887 in the discovery cohort and 0.9512 in the validation cohort (49 CKD vs 63 HC). Importantly, the AUC reaches 0.8986 in the extra diagnosis cohort from Hangzhou. Moreover, Thalassospira and Akkermansia are increased with CKD progression. Thirteen operational taxonomy units are correlated with six clinical indicators of CKD. In conclusion, this study comprehensively characterizes gut microbiome in non‐dialysis CKD and demonstrates the potential of microbial markers as non‐invasive diagnostic tools for CKD in different regions of China.
The Performance‐Determining Role of Lewis Bases in Dye‐Sensitized Solar Cells Employing Copper‐Bisphenanthroline Redox Mediators
Authors: Fürer Sebastian O. , Milhuisen Rebecca A. , Kashif Muhammad K. , Raga Sonia R. , Acharya Shravan S. , Forsyth Craig , Liu Maning , Frazer Laszlo , Duffy Noel W. , Ohlin C. André , Funston Alison M. , Tachibana Yasuhiro , Bach Udo 
Published: September 2020

AbstractCopper redox mediators have enabled open‐circuit voltages (VOC) of over 1.0 V in dye‐sensitized solar cells (DSCs) and have helped to establish DSCs as the most promising solar cell technology in low‐light conditions. The addition of additives such as 4‐tert‐butylpyridine (tBP) to these electrolytes has helped in achieving high solar cell performances. However, emerging evidence suggests that tBP coordinates to the Cu(II) species and limits the performance of these electrolytes. To date, the implications of this coordination are poorly understood. Here, the importance of Lewis base additives for the successful implementation of copper complexes as redox mediators in DSCs is demonstrated. Two redox couples, [Cu(dmp)2]+/2+ and [Cu(dpp)2]+/2+ (with dmp = 2,9‐dimethyl‐1,10‐phenanthroline and dpp = 2,9‐diphenyl‐1,10‐phenanthroline) in combination with three different Lewis bases, TFMP (4‐(trifluoromethyl)pyridine), tBP, and NMBI (1‐methyl‐benzimidazole), are considered. Through single‐crystal X‐ray diffraction analysis, absorption, and 1H‐NMR spectroscopies, the coordination of Lewis bases to the Cu(II) centers are studied. This coordination efficiently suppresses recombination losses and is crucial for high performing solar cells. If, however, the coordination involves a ligand exchange, as is the case for [Cu(dpp)2]+/2+, the redox mediator regeneration at the counter electrode is significantly retarded and the solar cells show current limitations.
Mock Oral Board Examinations via Web‐based Video Teleconferencing in the Era of COVID‐19
Authors: Chhabra Neeraj , Winfield Ashlea , Dyer Sean , Hedayati Tarlan 
Published: September 2020

AbstractOwing to infection control measures necessitated by the COVID‐19 pandemic, many educational didactic components within residency programs have needed to adapt to virtual formats. We describe and evaluate the transition of an in‐person mock oral board certification examination to an entirely virtual format.Oral board cases consisting of two single cases and one triple case were adapted to a virtual format using a Web‐based video teleconferencing platform. Faculty examiners underwent 20‐minute training sessions prior to the examination. Both resident examinees and faculty examiners completed postexamination surveys. The system usability scale (SUS) was used to assess the usability of the new format by the faculty examiners.Fifteen resident examinees completed the mock virtual oral board examination with eight faculty examiners. All faculty members completed the postexamination survey. The mean (±SD) SUS score was 90.6 (±11.5) out of a maximum of 100. Eleven of 15 (73%) resident examinees completed the postexamination survey. All respondents agreed or strongly agreed that examiner instructions were easy to understand and that examiners were adept at using the Web‐based platform. Some technical issues were encountered including audio difficulties for some examiners. Respondents were split regarding personal preference for virtual or in‐person mock oral board formats.Utilizing video teleconferencing software to provide a virtual, Web‐based alternative to in‐person mock oral board examination was feasible, and the virtual format was shown to have high usability despite minimal training time for experienced faculty examiners.
Gas–liquid flows through porous media in microgravity: The International Space Station Packed Bed Reactor Experiment
Authors: Motil Brian J. , Ramé Enrique , Salgi Paul , Taghavi Mahsa , Balakotaiah Vemuri 
Published: September 2020

AbstractExperimental results on pressure drop and flow patterns for gas–liquid flow through packed beds obtained in the International Space Station with two types of packing are presented and analyzed. It is found that the pressure drop depends on the packing wettability in the viscous–capillary (V–C) regime and this dependence is compared with previously published results developed using short duration low‐gravity aircraft tests. Within the V–C regime, the capillary contribution is the dominant force contributing to the pressure drop for the wetting case (glass) versus the viscous contribution dominating for the non‐wetting case (Teflon). Outside of the V–C regime, it is also found that hysteresis effects that are often strong in normal gravity gas–liquid flows are greatly diminished in microgravity and pressure drop is nearly independent of packing wettability. A flow pattern transition map from bubble to pulse flow is also compared with the earlier aircraft data.
Local gas–liquid slip velocity distribution in bubble columns and its relationship with heat transfer
Authors: Zhang Xi‐Bao , Luo Zheng‐Hong 
Published: September 2020

AbstractThe knowledge of the local gas–liquid slip velocity distribution can offer a better understanding for the complex transport phenomena in bubble columns. In this work, CFD–PBM simulations are carried out to investigate the effect of superficial gas velocities, axial positions, and scale of bubble columns on the time‐averaged radial profiles of gas–liquid slip velocities. Furthermore, the relationship between local slip velocities and local heat transfer coefficients in pilot‐scale bubble columns at superficial gas velocities of 0.05 m/s, 0.20 m/s, and 0.35 m/s is studied. The results indicate that the slip velocities decrease with the increase of r/R (r‐radial position, R‐column radius), while increase with increasing superficial gas velocities in general. In the fully developed region, the axial positions have small impact on the local slip velocities. A strong linear relation between heat transfer coefficients and slip velocities in the fully flow developed region is observed.
Improving mixing performance by curved‐blade static mixer
Authors: Mahmoodi Hassan , Razzaghi Kiyanoosh , Shahraki Farhad 
Published: September 2020

AbstractThis article addresses design modification to a flat‐blade static mixer to enhance mixing performance. The static mixer elements used in this work consist of four blades with curvature made to intensify turbulent‐like flow, while reducing the pressure drop. The blades were mounted on a cylindrical housing with 45° rotation relative to the axial direction. The mixer assembly was used in three different arrangements of 8, 10, and 14 elements for a range of Reynolds number between 600 and 7,000. The coefficient of variance (COV) of samples was used to measure the mixing quality. The curved‐blade mixer provides considerable improvement in mixing quality compared with the flat‐blade mixer and comparable to the SMX mixer. Compared with the flat‐blade static mixer, the new design reduces the COV by up to about 50%. This effect is more pronounced when the number of mixing elements increases. Furthermore, the friction factors for the modified mixer, obtained at a wide range of Reynolds number, were apparently smaller than those for the flat‐blade, SMX, and SMV mixers. The correlation presented for the friction factor, when all mixer arrangements and aspect ratios were considered, supports the experimental data with ±15% deviation.
Multi‐stage economic model predictive control for a gold cyanidation leaching process under uncertainty
Authors: Jia Runda , You Fengqi 
Published: September 2020

ABSTRACTIn order to dynamically operate the gold cyanidation leaching process (GCLP) under uncertainty, a multi‐stage economic model predictive control (EMPC) is proposed for GCLP for the transient and steady‐state economic optimization. The proposed multi‐stage EMPC is composed of two steps. In the first step, the unmeasurable uncertain parameters are estimated by using Tikhonov regularization based method, so as to avoid amplification and propagation of the noise measurements into the estimation. Based on the estimated results, the scenario tree for multi‐stage EMPC is generated from the historical data using a data‐driven approach, and the control inputs are obtained from solving the resulting large nonlinear programming problem (NLP) at each sampling point. The resulting uncertainty model and the probability of each scenario are more consistent with the actual industrial GCLP, and the solutions are less conservative. The efficiency of the proposed multi‐stage EMPC is verified through a simulated industrial GCLP. Compared with other EMPC methods, including classic EMPC and multi‐stage EMPC with box uncertainty region, the proposed method can reduce the economic cost while accounting for the constraints at the same time.
RP2‐associated retinal disorder in a Japanese cohort: Report of novel variants and a literature review, identifying a genotype–phenotype association
Authors: Fujinami Kaoru , Liu Xiao , Ueno Shinji , Mizota Atsushi , Shinoda Kei , Kuniyoshi Kazuki , Fujinami‐Yokokawa Yu , Yang Lizhu , Arno Gavin , Pontikos Nikolas , Kameya Shuhei , Kominami Taro , Terasaki Hiroko , Sakuramoto Hiroyuki , Nakamura Natsuko , Kurihara Toshihide , Tsubota Kazuo , Miyake Yozo , Yoshiake Kazutoshi , Iwata Takeshi , Tsunoda Kazushige ,   Japan Eye Genetics Consortium Study Group
Published: September 2020

AbstractThe retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X‐linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2‐associated retinal disorder (RP2‐RD) from four Japanese families in a nationwide cohort. A systematic review of RP2‐RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10–47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52–2.0)/1.10 (0.52–1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2‐RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.