bluuebunny/crossref_metadata_2025 huggingface dataset:
Structures in multiple conformations reveal distinct transition metal and proton pathways in an Nramp transporter
Authors: Bozzi Aaron T , Zimanyi Christina M , Nicoludis John M , Lee Brandon K , Zhang Casey H , Gaudet Rachelle
Published: February 2019

Nramp family transporters—expressed in organisms from bacteria to humans—enable uptake of essential divalent transition metals via an alternating-access mechanism that also involves proton transport. We present high-resolution structures of Deinococcus radiodurans (Dra)Nramp in multiple conformations to provide a thorough description of the Nramp transport cycle by identifying the key intramolecular rearrangements and changes to the metal coordination sphere. Strikingly, while metal transport requires cycling from outward- to inward-open states, efficient proton transport still occurs in outward-locked (but not inward-locked) DraNramp. We propose a model in which metal and proton enter the transporter via the same external pathway to the binding site, but follow separate routes to the cytoplasm, which could facilitate the co-transport of two cationic species. Our results illustrate the flexibility of the LeuT fold to support a broad range of substrate transport and conformational change mechanisms.
Flexible nitrogen utilisation by the metabolic generalist pathogen Mycobacterium tuberculosis
Authors: Agapova Aleksandra , Serafini Agnese , Petridis Michael , Hunt Debbie M , Garza-Garcia Acely , Sohaskey Charles D , de Carvalho Luiz Pedro Sório
Published: January 2019

Bacterial metabolism is fundamental to survival and pathogenesis. We explore how Mycobacterium tuberculosis utilises amino acids as nitrogen sources, using a combination of bacterial physiology and stable isotope tracing coupled to mass spectrometry metabolomics methods. Our results define core properties of the nitrogen metabolic network from M. tuberculosis, such as: (i) the lack of homeostatic control of certain amino acid pool sizes; (ii) similar rates of utilisation of different amino acids as sole nitrogen sources; (iii) improved nitrogen utilisation from amino acids compared to ammonium; and (iv) co-metabolism of nitrogen sources. Finally, we discover that alanine dehydrogenase is involved in ammonium assimilation in M. tuberculosis, in addition to its essential role in alanine utilisation as a nitrogen source. This study represents the first in-depth analysis of nitrogen source utilisation by M. tuberculosis and reveals a flexible metabolic network with characteristics that are likely a product of evolution in the human host.
Surface color and predictability determine contextual modulation of V1 firing and gamma oscillations
Authors: Peter Alina , Uran Cem , Klon-Lipok Johanna , Roese Rasmus , van Stijn Sylvia , Barnes William , Dowdall Jarrod R , Singer Wolf , Fries Pascal , Vinck Martin
Published: February 2019

The integration of direct bottom-up inputs with contextual information is a core feature of neocortical circuits. In area V1, neurons may reduce their firing rates when their receptive field input can be predicted by spatial context. Gamma-synchronized (30–80 Hz) firing may provide a complementary signal to rates, reflecting stronger synchronization between neuronal populations receiving mutually predictable inputs. We show that large uniform surfaces, which have high spatial predictability, strongly suppressed firing yet induced prominent gamma synchronization in macaque V1, particularly when they were colored. Yet, chromatic mismatches between center and surround, breaking predictability, strongly reduced gamma synchronization while increasing firing rates. Differences between responses to different colors, including strong gamma-responses to red, arose from stimulus adaptation to a full-screen background, suggesting prominent differences in adaptation between M- and L-cone signaling pathways. Thus, synchrony signaled whether RF inputs were predicted from spatial context, while firing rates increased when stimuli were unpredicted from context.
Transsynaptic interactions between IgSF proteins DIP-α and Dpr10 are required for motor neuron targeting specificity
Authors: Ashley James , Sorrentino Violet , Lobb-Rabe Meike , Nagarkar-Jaiswal Sonal , Tan Liming , Xu Shuwa , Xiao Qi , Zinn Kai , Carrillo Robert A
Published: February 2019

The Drosophila larval neuromuscular system provides an ideal context in which to study synaptic partner choice, because it contains a small number of pre- and postsynaptic cells connected in an invariant pattern. The discovery of interactions between two subfamilies of IgSF cell surface proteins, the Dprs and the DIPs, provided new candidates for cellular labels controlling synaptic specificity. Here we show that DIP-α is expressed by two identified motor neurons, while its binding partner Dpr10 is expressed by postsynaptic muscle targets. Removal of either DIP-α or Dpr10 results in loss of specific axonal branches and NMJs formed by one motor neuron, MNISN-1s, while other branches of the MNISN-1s axon develop normally. The temporal and spatial expression pattern of dpr10 correlates with muscle innervation by MNISN-1s during embryonic development. We propose a model whereby DIP-α and Dpr10 on opposing synaptic partners interact with each other to generate proper motor neuron connectivity.
A theory on individual characteristics of successful coding challenge solvers
Authors: Wyrich Marvin , Graziotin Daniel , Wagner Stefan
Published: February 2019

Background

Assessing a software engineer’s ability to solve algorithmic programming tasks has been an essential part of technical interviews at some of the most successful technology companies for several years now. We do not know to what extent individual characteristics, such as personality or programming experience, predict the performance in such tasks. Decision makers’ unawareness of possible predictor variables has the potential to bias hiring decisions which can result in expensive false negatives as well as in the unintended exclusion of software engineers with actually desirable characteristics.

Methods

We conducted an exploratory quantitative study with 32 software engineering students to develop an empirical theory on which individual characteristics predict the performance in solving coding challenges. We developed our theory based on an established taxonomy framework by Gregor (2006).

Results

Our findings show that the better coding challenge solvers also have better exam grades and more programming experience. Furthermore, conscientious as well as sad software engineers performed worse in our study. We make the theory available in this paper for empirical testing.

Discussion

The theory raises awareness to the influence of individual characteristics on the outcome of technical interviews. Should the theory find empirical support in future studies, hiring costs could be reduced by selecting appropriate criteria for preselecting candidates for on-site interviews and potential bias in hiring decisions could be reduced by taking suitable measures.
Software engineering principles to improve quality and performance of R software
Authors: Russell Seth , Bennett Tellen D. , Ghosh Debashis
Published: February 2019

Today’s computational researchers are expected to be highly proficient in using software to solve a wide range of problems ranging from processing large datasets to developing personalized treatment strategies from a growing range of options. Researchers are well versed in their own field, but may lack formal training and appropriate mentorship in software engineering principles. Two major themes not covered in most university coursework nor current literature are software testing and software optimization. Through a survey of all currently available Comprehensive R Archive Network packages, we show that reproducible and replicable software tests are frequently not available and that many packages do not appear to employ software performance and optimization tools and techniques. Through use of examples from an existing R package, we demonstrate powerful testing and optimization techniques that can improve the quality of any researcher’s software.
Methods of body temperature assessment in Conolophus subcristatus, Conolophus pallidus (Galaìpagos land iguanas), and Amblyrhynchus cristatus X C. subcristatus hybrid
Authors: Valle Carlos A. , Grijalva Colon J. , Calle Paul P. , Muñoz-Pérez Juan Pablo , Quezada Galo , Vera Carlos A. , Lewbart Gregory A.
Published: February 2019

Since cardiovascular, respiratory, and metabolic systems of reptiles are affected by temperature, accurate measurements are of great importance in both captive husbandry and research. Ectothermic animals generally have core body temperatures close to ambient temperature but can differ from the immediate environment if they are using sunlight to thermoregulate. Many zoological facilities and exotic pet caregivers have begun using infrared temperature guns to assess ambient temperatures of reptile enclosures but there are currently few studies assessing the efficacy of these devices for measuring the body temperatures of reptiles. Conolophus subcristatus, Conolophus pallidus (Galápagos land iguanas), and Amblyrhynchus cristatus X C. subcristatus hybrid are robust land iguanas endemic to the Galápagos archipelago. By comparing the infrared body temperature measurements of land iguanas against virtual simultaneous collection of cloacal temperatures obtained using a thermocouple thermometer, we sought to assess the efficacy of this non-invasive method. We found that internal body temperature can be predicted with a high level of accuracy from three external body temperature sites, providing a good non-invasive method that avoids the capture of animals.
Transcriptome-wide characterization and functional analysis of MATE transporters in response to aluminum toxicity in Medicago sativa L.
Authors: Min Xueyang , Jin Xiaoyu , Liu Wenxian , Wei Xingyi , Zhang Zhengshe , Ndayambaza Boniface , Wang Yanrong
Published: January 2019

Multidrug and toxic compound extrusion (MATE) transporters contribute to multidrug resistance and play major determinants of aluminum (Al) tolerance in plants. Alfalfa (Medicago sativa L.) is the most extensively cultivated forage crop in the world, yet most alfalfa cultivars are not Al tolerant. The basic knowledge of the MATE transcripts family and the characterisation of specific MATE members involved in alfalfa Al stress remain unclear. In this study, 88 alfalfa MATE (MsMATE) transporters were identified at the whole transcriptome level. Phylogenetic analysis classified them into four subfamilies comprising 11 subgroups. Generally, five kinds of motifs were found in group G1, and most were located at the N-terminus, which might confer these genes with Al detoxification functions. Furthermore, 10 putative Al detoxification-related MsMATE genes were identified and the expression of five genes was significantly increased after Al treatment, indicating that these genes might play important roles in conferring Al tolerance to alfalfa. Considering the limited functional understanding of MATE transcripts in alfalfa, our findings will be valuable for the functional investigation and application of this family in alfalfa.
A new species of Escallonia (Escalloniaceae) from the inter-Andean tropical dry forests of Bolivia
Authors: Zapata Felipe , Villarroel Daniel
Published: January 2019

Over the last two decades, renewed fieldwork in poorly explored areas of the tropical Andes has dramatically increased the comparative material available to study patterns of inter- and intraspecific variation in tropical plants. In the course of a comprehensive study of the genus Escallonia, we found a group of specimens with decumbent branching, small narrowly elliptic leaves, inflorescences with up to three flowers, and flowers with red petals. This unique combination of traits was not present in any known species of the genus. To evaluate the hypothesis that these specimens belonged to a new species, we assessed whether morphological variation between the putative new species and all currently known Escallonia species was discontinuous. The lack of overlap in tolerance regions for vegetative and reproductive traits combined with differences in habit, habitat, and geographic distribution supported the hypothesis of the new species, which we named Escallonia harrisii. The new species grows in sandstone inter-Andean ridges and cliffs covered with dry forest, mostly on steep slopes between 1,300–2,200 m in southern Bolivia. It is readily distinct in overall leaf and flower morphology from other Escallonia species in the region, even though it does not grow in sympatry with other species. Because E. harrisii is locally common it may not be threated at present, but due to its restricted geographic distribution and the multiple threats of the tropical dry forests it could become potentially vulnerable.
A reassessment of Asterolasia correifolia (Rutaceae) with descriptions of the newly recognised A. exasperata and A. sola
Authors: Alvarez Philippa R. , Duretto Marco F.
Published: February 2019

Asterolasia correifolia (A.Juss.) Benth. (Rutaceae) is revised and a narrower circumscription adopted; it is now considered to be endemic to New South Wales (NSW). Plants from the Northern Tablelands (NSW) and the Carnarvon Range (Queensland) represent distinct species and A. exasperata P.R.Alvarez & Duretto and A. sola Duretto & P.R.Alvarez are newly described for them. These species are distinguished from A. correifolia by leaf shape, the size of the hairs on the stems and leaves, and by having smaller inflorescences. Descriptions, illustrations, ecological and conservation notes are provided for A. correifolia, A. exasperata, and A. sola. A key to Asterolasia for eastern Australia is also provided.
Amide‐Forming Ligation Reactions
Authors: Pattabiraman Vijaya R. , Ogunkoya Ayodele O. , Bode Jeffrey W.
Published: January 2019

One of the long‐standing pursuits of synthetic organic chemists is the development of chemical methods for the synthesis of peptides and proteins as tools for understanding biological processes and providing therapeutic solutions to human diseases. The advent of chemoselective ligation reactions for the chemical synthesis of peptides and proteins has enabled synthetic chemists to realize this long‐held dream. In an amide‐forming ligation reaction, two uniquely placed functional groups within the peptide allow peptide or protein segments to be joined in a chemoselective manner with an amide bond. In this chapter, some of the early methods based on principles of the capture/rearrangement strategy for ligation of peptides are catalogued, followed by some of the most versatile and well‐established contemporary methods for the preparation of linear/cyclic peptides and proteins such as the native chemical ligation (NCL) and the α‐ketoacid–hydroxylamine (KAHA) ligation. The chapter concludes with some of the most promising new generation ligation methods such as the potassium acyltrifluoroborate–hydroxylamine (KAT) ligation. The tremendous progress in the past two decades in the development of several ligation methods that rely on a pair of unique functional groups is set to expand the horizons of fully functional proteins and multi‐protein assemblies that are purely synthetically prepared. Although contemporary ligation reactions do not match the speed and efficiency at which proteins are assembled in biological systems, the repertoire of chemoselective amide‐forming ligation methods has already enabled synthetic protein chemistry to surpass biology in terms of chemical and structural diversity.
A Terminally Tetrafluorinated Nonfullerene Acceptor for Well‐Performing Alloy Ternary Solar Cells
Authors: Lv Ruizhi , Chen Dong , Liao Xunfan , Chen Lie , Chen Yiwang
Published: January 2019

Fabricating ternary solar cells is a pivotal strategy to improve the power conversion efficiencies (PCEs) of organic photovoltaic devices. However, it is still a challenge to simultaneously improve the performance parameters of ternary devices. Therefore, the third ingredient in ternary blends should be precisely designed or selected. Herein, a new medium‐bandgap small‐molecule acceptor, namely, 3,9‐bis(2‐methylene‐(3‐(1‐(3,5‐dimethylphenyl)‐1cyanomethylene)indanone))‐5,5,11,11‐tetrakis‐(4‐hexylphenyl)dithieno[2,3‐d:2′,3′‐d′]‐sindaceno[1,2‐b:5,6‐b′]dithiophene (ITIF), is synthesized by end‐capping with a new fluorinated, asymmetric terminal group, (Z)‐2‐(3,5‐difluorophenyl)‐2‐(3‐oxo‐2,3‐dihydro‐1H‐inden‐1‐ylidene) acetonitrile. Replacing the CN substituent with the asymmetric 3,5‐difluorophenyl substituent obviously up‐shifts the lowest unoccupied molecular orbital (LUMO) level of ITIF to −3.78 eV, enlarges the bandgap to 1.82 eV, and improves the absorption coefficient to ≈50% higher than that of 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)indanone))‐5,5,11,11‐tetrakis‐(4‐hexylphenyl)dithieno[2,3‐d:2′,3′‐d′]‐sindaceno[1,2‐b:5,6‐b′]dithiophene (ITIC). Due to the similar structures, ITIF and ITIC can combine as an alloyed acceptor, which makes it convenient to tune the morphology and optical and electrochemical properties of ternary blends. The enhanced absorption coefficient of ITIF and the rapid fluorescence resonance energy transfer from ITIF to ITIC remarkably improve the absorption of the ternary blend film, hence compensating for the external quantum efficiency (EQE) curves. When ITIF is introduced into ternary solar cells based on poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione)] (PBDB‐T):ITIF:ITIC blends, the PCEs of the ternary devices are increased from 9.2% to 10.5%, and the short‐circuit currents, open‐circuit voltages, and fill factors are simultaneously improved.
Superhydrophilic Graphdiyne Accelerates Interfacial Mass/Electron Transportation to Boost Electrocatalytic and Photoelectrocatalytic Water Oxidation Activity
Authors: Li Jian , Gao Xin , Li Zhenzhu , Wang Jing‐Hao , Zhu Lei , Yin Chen , Wang Yang , Li Xu‐Bing , Liu Zhongfan , Zhang Jin , Tung Chen‐Ho , Wu Li‐Zhu
Published: January 2019

Graphdiyne (GDY), with a highly π‐conjugated structure of sp2‐ and sp‐hybridized carbon, has triggered a huge interest in water splitting. However, all of the systems perform with no consideration of the surface wettability of GDY. Herein, for the first time, the fabrication of superhydrophilic GDY electrode via air‐plasma for oxygen evolution is described. As a representative catalyst, ultrathin CoAl‐LDH (CO32−) nanosheets have been successfully assembled onto the superhydrophilic GDY electrostatically. The resulting superhydrophilic CoAl‐LDH/GDY electrode exhibites superior activity with an overpotential of ≈258 mV to reach 10 mA cm−2. The turnover frequency (TOF) is calculated to be ≈0.60 s−1 at η = 300 mV, which is the best record in both CoAl‐based and GDY‐based layered double hydroxides (LDH) electrocatalysts for oxygen evolution. Density functional theory (DFT) calculations reveal that superhydrophilic GDY has stronger interactions with catalysts and attracts H2O molecules around catalysts, thus facilitating interfacial mass/electron transportation. Further, the fabrication is capable of improving the photoelectrochemical oxygen evolution activity remarkably. The results show the great potential of superhydrophilic GDY to boost water oxidation activity by promoting interfacial mass/electron transportation.
Highly Surface‐Wrinkled and N‐Doped CNTs Anchored on Metal Wire: A Novel Fiber‐Shaped Cathode toward High‐Performance Flexible Li–CO2 Batteries
Authors: Li Yinchuan , Zhou Jingwen , Zhang Tingbo , Wang Tianshuai , Li Xuelian , Jia Yafu , Cheng Jianli , Guan Qun , Liu Enzuo , Peng Huisheng , Wang Bin
Published: January 2019

Li–CO2 batteries are regarded as a promising candidate for the next‐generation high‐performance electrochemical energy storage system owing to their ultrahigh theoretical energy density and environmentally friendly CO2 fixation ability. Until now, the majority of reported catalysts for Li–CO2 batteries are in the powder state. Thus, the air electrodes are produced in 2D rigid bulk structure and their electrochemical properties are negatively influenced by binder. The nondeformable feature and unsatisfactory performance of the cathode have already become the main obstacles that hinder Li–CO2 batteries toward ubiquity for wearable electronics. In this work, for the first time, a flexible hybrid fiber is reported comprising highly surface‐wrinkled and N‐doped carbon nanotube (CNT) networks anchored on metal wire as the cathode integrated with high performance and high flexibility for fiber‐shaped Li–CO2 battery. It exhibits a large discharge capacity as high as 9292.3 mAh g−1, an improved cycling performance of 45 cycles, and a decent rate capability. A quasi‐solid‐state flexible fiber‐shaped Li–CO2 battery is constructed to illustrate the advantages on mechanical flexibility of this fiber‐shaped cathode. Experiments and theoretical simulations prove that those doped pyridinic nitrogen atoms play a critical role in facilitating the kinetics of CO2 reduction and evolution reaction, thereby enabling distinctly enhanced electrochemical performance.
Extended Electrochemical Window of Solid Electrolytes via Heterogeneous Multilayered Structure for High‐Voltage Lithium Metal Batteries
Authors: Duan Hui , Fan Min , Chen Wan‐Ping , Li Jin‐Yi , Wang Peng‐Fei , Wang Wen‐Peng , Shi Ji‐Lei , Yin Ya‐Xia , Wan Li‐Jun , Guo Yu‐Guo
Published: January 2019

In response to the call for safer high‐energy‐density storage systems, high‐voltage solid‐state Li metal batteries have attracted extensive attention. Therefore, solid electrolytes are required to be stable against both Li anode and high‐voltage cathodes; nevertheless, the requirements still cannot be completely satisfied. Herein, a heterogeneous multilayered solid electrolyte (HMSE) is proposed to broaden electrochemical window of solid electrolytes to 0–5 V, through different electrode/electrolyte interfaces to overcome the interfacial instability problems. Oxidation‐resistance poly(acrylonitrile) (PAN) is in contact with the cathode, while reduction tolerant polyethylene glycol diacrylate contacts with Li metal anode. A Janus and flexible PAN@Li1.4Al0.4Ge1.6(PO4)3 (80 wt%) composite electrolyte is designed as intermediate layer to inhibit dendrite penetration and ensure compact interface. Paired with LiNi0.6Co0.2Mn0.2O2 and LiNi0.8Co0.1Mn0.1O2 cathodes, which are rarely used in solid‐state batteries, the solid‐state Li metal batteries with HMSE exhibit excellent electrochemical performance including high capacity and long cycle life. Besides, the Li||Li symmetric batteries maintain a stable polarization less than 40 mV for more than 1000 h under 2 mA cm−2 and effective inhibition of dendrite formation. This study offers a promising approach to extend the applications of solid electrolytes for high‐voltage solid‐state Li metal batteries.
Uncovering the Effect of Lattice Strain and Oxygen Deficiency on Electrocatalytic Activity of Perovskite Cobaltite Thin Films
Authors: Liu Xi , Zhang Lei , Zheng Yun , Guo Zheng , Zhu Yunmin , Chen Huijun , Li Fei , Liu Peipei , Yu Bo , Wang Xinwei , Liu Jiang , Chen Yan , Liu Meilin
Published: January 2019

Developing cost effective electrocatalysts with high oxygen evolution reaction (OER) activity is essential for large‐scale application of many electrochemical energy systems. Although the impacts of either lattice strain or oxygen defects on the OER performance of oxide catalysts have been extensively investigated, the effects of both factors are normally treated separately. In this work, the coupled effects of both strain and oxygen deficiency on the electrocatalytic activity of La0.7Sr0.3CoO3−δ (LSC) thin films grown on single crystal substrates (LaAlO3 (LAO) and SrTiO3 (STO)) are investigated. Electrochemical tests show that the OER activities of LSC films are higher under compression than under tension, and are diminished as oxygen vacancies are introduced by vacuum annealing. Both experimental and computational results indicate that the LSC films under tension (e.g., LSC/STO) have larger oxygen deficiency than the films under compression (e.g., LSC/LAO), which attribute to smaller oxygen vacancy formation energy. Such strain‐induced excessive oxygen vacancies in the LSC/STO increases the eg state occupancy and enlarges the energy gap between the O 2p and Co 3d band, resulting in lower OER activity. Understanding the critical role of strain–defect coupling is important for achieving the rational design of highly active and durable catalysts for energy devices.
Isomerization of Perylene Diimide Based Acceptors Enabling High‐Performance Nonfullerene Organic Solar Cells with Excellent Fill Factor
Authors: Luo Zhenghui , Liu Tao , Chen Zhanxiang , Xiao Yiqun , Zhang Guangye , Huo Lijun , Zhong Cheng , Lu Xinhui , Yan He , Sun Yanming , Yang Chuluo
Published: January 2019

A strategy that employs the central‐core regiochemistry to develop two isomeric perylene diimide (PDI)‐based small molecular acceptors (SMAs), BPT‐Se and BPT‐Se1, is introduced, and the effect of the central‐core regiochemistry on the optical, electronic, charge‐transport, photovoltaic, and morphological properties of the molecules and their devices is investigated. The PDBT‐T1:BPT‐Se1‐based device delivers a power conversion efficiency (PCE) of 9.54% with an excellent fill factor (FF) of 73.2%, while the BPT‐Se‐based device yields a PCE of 7.78%. The large improvement of PCE upon isomerization of BPT‐Se should be ascribed to the concurrent enhancement of FF, short circuit current ( JSC), and open circuit voltage (VOC) of the PDBT‐T1:BPT‐Se1 devices. The higher FF of the organic solar cells (OSCs) based on PDBT‐T1:BPT‐Se1 can be attributed to the higher charge dissociation and charge collection efficiency, less bimolecular combination, more balanced µh/µe, better molecular packing and a more favorable morphology. It is worth mentioning that the FF of 73.2% is the highest value for PDI‐based SMAs OSCs to date. The result shows that regiochemistry of the central core in PDI‐based SMAs greatly affects the physicochemical properties and photovoltaic performance. The success of the isomerization strategy offers exciting prospects for the molecular design of PDI‐based SMAs.
The acceptability of serum sample storage for hepatitis C viral load analysis in chronic hepatitis C patients
Authors: Huang Ying‐Chou , Liu Shu‐Fen , Liu Hung‐Yin , Huang Chung‐Feng , Yeh Ming‐Lun , Dai Chia‐Yen , Tsai Pei‐Chien , Chen Shinn‐Cherng , Yu Ming‐Lung , Chuang Wan‐Long , Huang Jee‐Fu
Published: January 2019

The detectable time duration of stored serum sample containing hepatitis C virus (HCV) remains to be elucidated. This study aimed to elucidate the viral load changes of the stored serum samples under 4°C conditions. We measured the viral loads collected from 13 patients (8 males, age = 60.5 ± 17.5 years). The samples were kept under 4°C conditions before analysis. Besides baseline viral load, the samples then were measured at days 3, 5, 7, 9, and 11 after collection, respectively. The measured viral loads at different time points were compared with baseline samples by using the Abbott RealTime HCV Assay in an m2000 PCR System. The viral loads of the 13 patients ranged between 0.151 and 10 648.491 KIU/mL at baseline. There were no significant differences in viral load changes between the baseline and the samples of other time points. The differences were within 0.45 log10 IU/mL (P > 0.05) at different time points. The study demonstrated that serum samples kept at 4°C for 11 days were acceptable for molecular analysis.
Ectodermal dysplasias: Classification and organization by phenotype, genotype and molecular pathway
Authors: Wright John Timothy , Fete Mary , Schneider Holm , Zinser Madelaine , Koster Maranke I. , Clarke Angus J. , Hadj‐Rabia Smail , Tadini Gianluca , Pagnan Nina , Visinoni Atila F. , Bergendal Birgitta , Abbott Becky , Fete Timothy , Stanford Clark , Butcher Clayton , D'Souza Rena N. , Sybert Virginia P. , Morasso Maria I.
Published: January 2019

An international advisory group met at the National Institutes of Health in Bethesda, Maryland in 2017, to discuss a new classification system for the ectodermal dysplasias (EDs) that would integrate both clinical and molecular information. We propose the following, a working definition of the EDs building on previous classification systems and incorporating current approaches to diagnosis: EDs are genetic conditions affecting the development and/or homeostasis of two or more ectodermal derivatives, including hair, teeth, nails, and certain glands. Genetic variations in genes known to be associated with EDs that affect only one derivative of the ectoderm (attenuated phenotype) will be grouped as non‐syndromic traits of the causative gene (e.g., non‐syndromic hypodontia or missing teeth associated with pathogenic variants of EDA “ectodysplasin”). Information for categorization and cataloging includes the phenotypic features, Online Mendelian Inheritance in Man number, mode of inheritance, genetic alteration, major developmental pathways involved (e.g., EDA, WNT “wingless‐type,” TP63 “tumor protein p63”) or the components of complex molecular structures (e.g., connexins, keratins, cadherins).
In‐vitro evaluation of a ciprofloxacin‐ and ivacaftor‐coated sinus stent against Pseudomonas aeruginosa biofilms
Authors: Cho Do‐Yeon , Lim Dong‐Jin , Mackey Calvin , Weeks Christopher G. , Garcia Jaime A. Peña , Skinner Daniel , Zhang Shaoyan , McCormick Justin , Woodworth Bradford A.
Published: January 2019

Background

We recently developed a novel ciprofloxacin‐coated sinus stent capable of releasing antibiotics over a sustained period of time. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that has synergistic bactericidal activity with ciprofloxacin and also enhances sinus mucociliary clearance. The objective of this study was to optimize and evaluate the efficacy of a ciprofloxacin‐ and ivacaftor‐releasing biodegradable sinus stent (CISS) in vitro.

Methods

A CISS was created by coating ciprofloxacin/ivacaftor‐embedded nanoparticles with an acrylate and ammonium methacrylate copolymer onto a biodegradable poly‐L‐lactic acid stent. In‐vitro evaluation of the CISS included: (1) assessment of drug stability in nanoparticles by zeta potential, and drug‐coating stability within the CISS using scanning electron microscopy (SEM); (2) determination of ciprofloxacin‐ and ivacaftor‐release kinetics; and (3) assessment of anti‒Pseudomonas aeruginosa biofilm formation by calculating relative optical density units (RODUs) compared with control stents at 590‐nm optical density.

Results

The presence of drugs and a uniform coating on the stent were confirmed by zeta potential and SEM. Sustained drug release was observed through 21 days without an initial burst release. Anti‐biofilm formation was observed after placing the CISS for 3 days onto a preformed 1‐day P aeruginosa biofilm. The CISS significantly reduced biofilm mass compared with bare stents and controls (RODUs at 590‐nm optical density; CISS, 0.31 ± 0.01; bare stent, 0.78 ± 0.12; control, 1.0 ± 0.00; p = 0.001; n = 3).

Conclusion

The CISS maintains a uniform coating and sustained delivery of drugs providing a marked reduction in P aeruginosa biofilm formation. Further studies evaluating the efficacy of CISS in a preclinical model are planned.
Does bilateral inferior turbinate reduction affect long‐term quality‐of‐life outcomes in patients undergoing endoscopic sinus surgery?
Authors: Scangas George A. , Bleier Benjamin S. , Husain Qasim , Holbrook Eric H. , Gray Stacey T. , Metson Ralph
Published: January 2019

Background

The objective of this study was to evaluate the impact of bilateral inferior turbinate reduction (BITR) on patient‐reported quality of life (QOL) following endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS).

Methods

This was a prospective cohort study. Patients with CRS, who were recruited from 10 different otolaryngologic practices between 2011 and 2014, completed the 22‐item Sino‐Nasal Outcome Test (SNOT‐22), Chronic Sinusitis Survey (CSS), and EuroQol 5 Dimension (EQ‐5D) survey at baseline, and at 12, 24, 36, and 48 months after ESS. A total of 113 patients who underwent ESS with BITR were compared to 788 patients who underwent ESS without BITR.

Results

Significant demographic and comorbid differences between BITR and non‐BITR cohorts included age (41 vs 49 years, p < 0.0001), presence of asthma (19% vs 36%, p < 0.0001), prior sinus surgery (22% vs 53%, p < 0.0001), and concurrent septoplasty (80% vs 53%, p < 0.0001), respectively. On univariate analysis, patients who underwent ESS with or without BITR were found to have statistically significant improvement in disease‐specific (SNOT‐22 and CSS) and general (EQ‐5D) QOL scores at years 1 through 4 (p < 0.05). On multivariate regression, however, the performance of BITR was not associated with any improvements in these outcome measures.

Conclusion

Patients undergoing ESS achieve similar long‐term improvement in both disease‐specific and general QOL regardless of the performance of concurrent BITR.
Single‐Electron Pumps and Quantum Current Metrology in the Revised SI
Authors: Scherer Hansjörg , Schumacher Hans Werner
Published: January 2019

The consequences of the revision of the International System of Units for electrical quantum metrology are discussed herein. Possible applications of single‐electron transport pump devices and other topical state‐of‐the‐art metrology methodologies based on quantum electrical effects are reviewed, with a focus on their potential for and implications on electrical metrology in the future.
Thermoresponsive Polymer Brush Modulation on the Direction of Motion of Phoretically Driven Janus Micromotors
Authors: Ji Yuxing , Lin Xiankun , Zhang Hongyue , Wu Yingjie , Li Junbai , He Qiang
Published: January 2019

We report a thermoresponsive poly(N‐isopropylacrylamide) (PNIPAM) brush functionalized Janus Au–Pt bimetallic micromotor capable of modulating the direction of motion with the change of the ambient temperature. The PNIPAM@Au–Pt micromotor moved along the Au–Pt direction with a speed of 8.5 μm s−1 in 1.5 % H2O2 at 25 °C (below the lower critical solution temperature (LCST) of PNIPAM), whereas it changed the direction of motion (i.e., along the Pt–Au direction) and the speed decreased to 2.3 μm s−1 at 35 °C (above LCST). Below LCST, PNIPAM brushes grafted on the Au side were hydrophilic and swelled, which permitted the electron transfer and proton diffusion on the Au side, and thus the motion is regarded as a self‐electrophoretic mechanism. However, PNIPAM brushes above LCST became hydrophobic and collapsed, and thus the driving mechanism switched to the self‐diffusiophoresis like that of Pt‐modified Janus silica motors. These motors could reversibly change the direction of motion with the transition of the hydrophobic and hydrophilic states of the grafted PNIPAM brushes. Such a thermoresponsive polymer brush functionalization method provides a new strategy for engineering the kinematic behavior of phoretically driven micro/nanomotors.
Mechanismusabhängige Regulation der ultraschnellen Dynamik von Wasser an Grenzflächen in Komplexen mit intrinsisch ungeordneten Proteinen
Authors: Chowdhury Aritra , Kovalenko Sergey A. , Aramburu Iker Valle , Tan Piau Siong , Ernsting Nikolaus P. , Lemke Edward A.
Published: January 2019

In diesem Beitrag wird das Zusammenspiel von Dynamik und Molekülerkennung bei intrinsisch ungeordneten Proteinen (IDPs) durch die Anwendung von zeitauflösenden Messtechniken im fs‐ bis ns‐Bereich beleuchtet. Die Konformations‐ und Wasserdynamik an Grenzflächen sowie deren Abschwächung durch die Bindung an ein Partnermolekül wurde anhand zweier IDPs, IBB und Nup153FG, untersucht. Beide Proteine binden an denselben Transportrezeptor (Importinβ), jedoch durch grundlegend verschiedene Bindungsmechanismen. Die Fluktuation des Lösungsmittels an der dynamischen Grenzfläche des Nup153FG‐Importinβ‐Komplexes blieb weitgehend ungestört und beschleunigte sich leicht im Vergleich zum ungebundenen Zustand. Im Gegensatz dazu wurde im IBB‐Importinβ‐Komplex eine beträchtliche relative Verlangsamung der Wasserdynamik an der starreren Grenzfläche beobachtet. Die Ergebnisse zeigen eine Korrelation zwischen der Hydratationsdynamik an Grenzflächen und der Plastizität von IDP‐Komplexen, was eine funktionelle Relevanz einer solchen Regulation impliziert, insbesondere auch für den nukleozytoplasmatischen Transport.
Light‐Gated Synthetic Protocells for Plasmon‐Enhanced Chemiosmotic Gradient Generation and ATP Synthesis
Authors: Chen Zhaowei , De Queiros Silveira Gleiciani , Ma Xuedan , Xie Yunsong , Wu Yimin A. , Barry Edward , Rajh Tijana , Fry H. Christopher , Laible Philip D. , Rozhkova Elena A.
Published: January 2019

Herein, we present a light‐gated protocell model made of plasmonic colloidal capsules (CCs) assembled with bacteriorhodopsin for converting solar energy into electrochemical gradients to drive the synthesis of energy‐storage molecules. This synthetic protocell incorporated an important intrinsic property of noble metal colloidal particles, namely, plasmonic resonance. In particular, the near‐field coupling between adjacent metal nanoparticles gave rise to strongly localized electric fields and resulted in a broad absorption in the whole visible spectra, which in turn promoted the flux of photons to bacteriorhodopsin and accelerated the proton pumping kinetics. The cell‐like potential of this design was further demonstrated by leveraging the outward pumped protons as “chemical signals” for triggering ATP biosynthesis in a coexistent synthetic protocell population. Hereby, we lay the ground work for the engineering of colloidal supraparticle‐based synthetic protocells with higher‐order functionalities.
Die selektive Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen
Authors: Wiesenfeldt Mario P. , Nairoukh Zackaria , Dalton Toryn , Glorius Frank
Published: January 2019

Die Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen und kann daher zur Verkürzung von Synthesewegen genutzt werden. Diese nützliche Transformation wird industriell verwendet und sollte weitere Durchbrüche in den angewandten Wissenschaften ermöglichen. Von zentraler Bedeutung für die Anwendung bei der Herstellung komplexer Moleküle ist die Kontrolle der Diastereo‐, Enantio‐ und Chemoselektivität. Im Allgemeinen ergibt die Hydrierung multisubstituierter Arene überwiegend das cis‐Isomer. Die Enantiokontrolle kann über chirale Auxiliare, Brønsted‐Säuren oder Übergangsmetallkatalysatoren erfolgen. Jüngere Arbeiten zeigen hoch chemoselektive Transformationen. Derartige Verfahren und die zugrunde liegenden Strategien werden hier erläutert, wobei der Schwerpunkt auf präparativ nützlichen Reaktion mit leicht verfügbaren Katalysatoren liegt.
Permeation von kleinen Molekülen durch Membrankanäle: Chemische Modifikation zur Quantifizierung des Transports über OmpF
Authors: Wang Jiajun , Bafna Jayesh Arun , Bhamidimarri Satya Prathyusha , Winterhalter Mathias
Published: January 2019

Biologische Kanäle erleichtern den Austausch von Molekülen über Membranen, es fehlen jedoch allgemeine Instrumente zur Quantifizierung des Transports. Häufig werden die funktionellen Eigenschaften von Membrankanälen mittels Elektrophysiologie untersucht. Frühere Studien der Ionenstromfluktuationen lassen jedoch keinen Rückschluss auf einen erfolgreichen Transport zu, d. h. die Unterscheidung zwischen einer Translokation und nur Bindung. Um beide Prozesse zu unterscheiden, wurde eine zusätzliche Barriere am Kanalausgang eingefügt, die als Zähler erfolgreicher Permeation dient. Hierzu vergleichen wir die Aufenthaltsdauer der Moleküle im nativen Kanal (wt) mit einer am Ausgang chemisch modifizierten Cysteinmutante. Als Beispiel verwenden wir den gut untersuchten Außenmembrankanal von E. coli, OmpF. Wie dessen bekannter Struktur zu entnehmen ist, ist die Glutaminsäure E181 unterhalb des Selektionsfilters und daher optimal geeignet. Das einzige Cystein im ansonsten cysteinfreien Protein wird über eine kovalente Bindung mit einem der beiden Blocker unterschiedlicher Größe (MTSES oder GLT) funktionalisiert. Mit diesem Konstrukt wird der Durchgang von unterschiedlichen Polyargininen als Model quantifiziert. In einer weiteren Messreihe wird Norfloxacin als Beispiel für die Permeation von Antibiotika untersucht.
Selective Emergence of the Halogen Bond in Ground and Excited States of Noble‐Gas–Chlorine Systems
Authors: Pirani Fernando , Cappelletti David , Falcinelli Stefano , Cesario Diego , Nunzi Francesca , Belpassi Leonardo , Tarantelli Francesco
Published: January 2019

Molecular‐beam scattering experiments and theoretical calculations prove the nature, strength, and selectivity of the halogen bonds (XB) in the interaction of halogen molecules with the series of noble gas (Ng) atoms. The XB, accompanied by charge transfer from the Ng to the halogen, is shown to take place in, and measurably stabilize, the collinear conformation of the adducts, which thus becomes (in contrast to what happens for other Ng‐molecule systems) approximately as bound as the T‐shaped form. It is also shown how and why XB is inhibited when the halogen molecule is in the 3Πu excited state. A general potential formulation fitting the experimental observables, based on few physically essential parameters, is proposed to describe the interaction accurately and is validated by ab initio computations.
Mechanism‐Dependent Modulation of Ultrafast Interfacial Water Dynamics in Intrinsically Disordered Protein Complexes
Authors: Chowdhury Aritra , Kovalenko Sergey A. , Aramburu Iker Valle , Tan Piau Siong , Ernsting Nikolaus P. , Lemke Edward A.
Published: January 2019

The recognition of intrinsically disordered proteins (IDPs) is highly dependent on dynamics owing to the lack of structure. Here we studied the interplay between dynamics and molecular recognition in IDPs with a combination of time‐resolving tools on timescales ranging from femtoseconds to nanoseconds. We interrogated conformational dynamics and surface water dynamics and its attenuation upon partner binding using two IDPs, IBB and Nup153FG, both of central relevance to the nucleocytoplasmic transport machinery. These proteins bind the same nuclear transport receptor (Importinβ) with drastically different binding mechanisms, coupled folding–binding and fuzzy complex formation, respectively. Solvent fluctuations in the dynamic interface of the Nup153FG‐Importinβ fuzzy complex were largely unperturbed and slightly accelerated relative to the unbound state. In the IBB‐Importinβ complex, on the other hand, substantial relative slowdown of water dynamics was seen in a more rigid interface. These results show a correlation between interfacial water dynamics and the plasticity of IDP complexes, implicating functional relevance for such differential modulation in cellular processes, including nuclear transport.
Exploiting the Hydrogen Bond Donor/Acceptor Properties of PN‐Heterocycles: Selective Anion Receptors for Hydrogen Sulfate
Authors: Deng Chun‐Lin , Bard Jeremy P. , Lohrman Jessica A. , Barker Joshua E. , Zakharov Lev N. , Johnson Darren W. , Haley Michael M.
Published: January 2019

We describe two novel hybrid receptors combining a phosphorus‐/nitrogen‐containing (PN) phosphonamidate heterocycle with urea recognition units in an arylethynyl backbone. Structural, spectroscopic and computational studies reveal that the origin of superior binding for hydrogen sulfate (HSO4−) anion is correlated with the formation of strong hetero‐complementary hydrogen bonds with the phosphonamidate motif. We further demonstrate that the hybrid host system is capable of capturing/transporting the HSO4−anion from an aqueous, biphasic system.
Near‐Infrared Afterglow Semiconducting Nano‐Polycomplexes for the Multiplex Differentiation of Cancer Exosomes
Authors: Lyu Yan , Cui Dong , Huang Jiaguo , Fan Wenxuan , Miao Yansong , Pu Kanyi
Published: January 2019

The detection of exosomes is promising for the early diagnosis of cancer. However, the development of suitable optical sensors remains challenging. We have developed the first luminescent nanosensor for the multiplex differentiation of cancer exosomes that bypasses real‐time light excitation. The sensor is composed of a near‐infrared semiconducting polyelectrolyte (ASPN) that forms a complex with a quencher‐tagged aptamer. The afterglow signal of the nanocomplex (ASPNC), being initially quenched, is turned on in the presence of aptamer‐targeted exosomes. Because detection of the afterglow takes place after the excitation, background signals are minimized, leading to an improved limit of detection that is nearly two orders of magnitude lower than that of fluorescence detection in cell culture media. Also, ASPNC can be easily tailored to detect different exosomal proteins by changing the aptamer sequence. This enables an orthogonal analysis of multiple exosome samples, potentially permitting an accurate identification of the cellular origin of exosomes for cancer diagnosis.
Damage growth‐based constitutive model of satin weave composites under different temperatures and strain rates
Authors: Hu Xueyao , Guo Weiguo , Wang Jianjun , Yuan Kangbo
Published: January 2019

In this study, a constitutive model, which took into account the temperature and strain rate dependences of progressive damage behavior, was developed to describe the compressive behavior of satin weave carbon/epoxy composites over the temperature range of 298–448 K and strain rate range of 0.001–1100 s−1. To further understand the mechanical behavior of satin weave carbon/epoxy composites, systematic experiments were first conducted using electronic universal testing machine and enhanced split Hopkinson pressure bar (SHPB) system. In addition, the progressive damage mechanism was observed with scanning electron microscope (SEM) and digital image correlation (DIC) technique. Results showed that the modulus and damage growth of composites are temperature and strain rate sensitive. Under quasi‐static compression, failure mode changed from shear fracture to kink‐band formation with increasing temperature. Samples failed predominantly by delamination under dynamic compression. It is shown that the mechanical behavior of satin weave composites obtained by the constitutive model agrees well with the experimental data over a wide range of temperature and strain rate. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47575.
Synergistic effects of polyethylene glycol and organic montmorillonite on the plasticization and enhancement of poly(lactic acid)
Authors: Chen Wenting , Chen Hao , Yuan Ya , Peng Shaoxian , Zhao Xipo
Published: January 2019

Poly(lactic acid) (PLA)/polyethylene glycol (PEG)/organic montmorillonite (OMMT) composites were prepared by melt blending, and their mechanical, rheological behavior, crystalline behavior, and thermal stability were investigated. Results showed that the elongation‐at‐break and notch‐impact strength of PLA/15PEG/1.5OMMT were 466.45% and 4.34 kJ m−2, respectively, which were nearly 42 and 2 times higher than those of PLA, respectively. The elongation‐at‐break of PLA/15PEG/1.5OMMT was also 33 times higher than that of PLA/15PEG and 30 times that of PLA/1.5OMMT. With addition of PEG, PLA chains could insert to OMMT effectively and increase the layer space of OMMT. The characteristics of dynamic behavior and fracture morphology showed that the plasticizer PEG could soften the PLA matrix, leading to easy plastic deformation. OMMT was well distributed in the PLA matrix and able to transfer the stress of external forces, thereby contributing to the matrix yielding initiation and expansion of polymer composites. The synergistic effect of OMMT and PEG was determined by studying the mechanical properties of PLA/PEG/OMMT composite. Differential scanning calorimetry and thermogravimetry studies revealed that OMMT as a nucleating agent improved crystallization and thermal stability. Thus, the synergistic effect of OMMT and PEG balanced the stiffness and toughness of PLA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47576.