bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divergent receptor proteins confer responses to different karrikins in two ephemeral weeds
Authors: Sun Yueming Kelly , Yao Jiaren , Scaffidi Adrian , Melville Kim T. , Davies Sabrina F. , Bond Charles S. , Smith Steven M. , Flematti Gavin R. , Waters Mark T. 
Published: March 2020

AbstractWildfires can encourage the establishment of invasive plants by releasing potent germination stimulants, such as karrikins. Seed germination of Brassica tournefortii, a noxious weed of Mediterranean climates, is strongly stimulated by KAR1, the archetypal karrikin produced from burning vegetation. In contrast, the closely-related yet non-fire-associated ephemeral Arabidopsisthaliana is unusual because it responds preferentially to KAR2. The α/β-hydrolase KARRIKIN INSENSITIVE 2 (KAI2) is the putative karrikin receptor identified in Arabidopsis. Here we show that B. tournefortii expresses three KAI2 homologues, and the most highly-expressed homologue is sufficient to confer enhanced responses to KAR1 relative to KAR2 when expressed in Arabidopsis. We identify two amino acid residues near the KAI2 active site that explain the ligand selectivity, and show that this combination has arisen independently multiple times within dicots. Our results suggest that duplication and diversification of KAI2 proteins could confer differential responses to chemical cues produced by environmental disturbance, including fire.
Hyperoxia induces glutamine-fuelled anaplerosis in retinal Müller cells
Authors: Singh Charandeep , Tran Vincent , McCollum Leah , Bolok Youstina , Allan Kristin , Yuan Alex , Hoppe George , Brunengraber Henri , Sears Jonathan E. 
Published: March 2020

AbstractAlthough supplemental oxygen is required to promote survival of severely premature infants, hyperoxia is simultaneously harmful to premature developing tissues such as in the retina. Here we report the effect of hyperoxia on central carbon metabolism in primary mouse Müller glial cells and a human Müller glia cell line (M10-M1 cells). We found decreased flux from glycolysis entering the tricarboxylic acid cycle in Müller cells accompanied by increased glutamine consumption in response to hyperoxia. In hyperoxia, anaplerotic catabolism of glutamine by Müller cells increased ammonium release two-fold. Hyperoxia induces glutamine-fueled anaplerosis that reverses basal Müller cell metabolism from production to consumption of glutamine.
Enhanced optical path and electron diffusion length enable high-efficiency perovskite tandems
Authors: Chen Bin , Baek Se-Woong , Hou Yi , Aydin Erkan , De Bastiani Michele , Scheffel Benjamin , Proppe Andrew , Huang Ziru , Wei Mingyang , Wang Ya-Kun , Jung Eui-Hyuk , Allen Thomas G. , Van Kerschaver Emmanuel , García de Arquer F. Pelayo , Saidaminov Makhsud I. , Hoogland Sjoerd , De Wolf Stefaan , Sargent Edward H. 
Published: March 2020

AbstractTandem solar cells involving metal-halide perovskite subcells offer routes to power conversion efficiencies (PCEs) that exceed the single-junction limit; however, reported PCE values for tandems have so far lain below their potential due to inefficient photon harvesting. Here we increase the optical path length in perovskite films by preserving smooth morphology while increasing thickness using a method we term boosted solvent extraction. Carrier collection in these films – as made – is limited by an insufficient electron diffusion length; however, we further find that adding a Lewis base reduces the trap density and enhances the electron-diffusion length to 2.3 µm, enabling a 19% PCE for 1.63 eV semi-transparent perovskite cells having an average near-infrared transmittance of 85%. The perovskite top cell combined with solution-processed colloidal quantum dot:organic hybrid bottom cell leads to a PCE of 24%; while coupling the perovskite cell with a silicon bottom cell yields a PCE of 28.2%.
Intermolecular [3+3] ring expansion of aziridines to dehydropiperi-dines through the intermediacy of aziridinium ylides
Authors: Eshon Josephine , Nicastri Kate A. , Schmid Steven C. , Raskopf William T. , Guzei Ilia A. , Fernández Israel , Schomaker Jennifer M. 
Published: March 2020

AbstractThe importance of N-heterocycles in drugs has stimulated diverse methods for their efficient syntheses. Methods that introduce significant stereochemical complexity are attractive for identifying new bioactive amine chemical space. Here, we report a [3 + 3] ring expansion of bicyclic aziridines and rhodium-bound vinyl carbenes to form complex dehydropiperidines in a highly stereocontrolled rearrangement. Mechanistic studies and DFT computations indicate that the reaction proceeds through formation of a vinyl aziridinium ylide; this reactive intermediate undergoes a pseudo-[1,4]-sigmatropic rearrangement to directly furnish heterocyclic products with net retention at the new C-C bond. In combination with asymmetric silver-catalyzed aziridination, enantioenriched scaffolds with up to three contiguous stereocenters are rapidly delivered. The mild reaction conditions, functional group tolerance, and high stereospecificity of this method are well-suited for appending piperidine motifs to natural product and complex molecules. Ultimately, our work establishes the value of underutilized aziridinium ylides as key intermediates for converting small, strained rings to larger N-heterocycles.
Quantifying bone marrow fat using standard T1-weighted magnetic resonance images in children with typical development and in children with cerebral palsy
Authors: Zhang Chuan , Slade Jill M. , Miller Freeman , Modlesky Christopher M. 
Published: March 2020

AbstractExcess bone marrow adiposity may have a negative effect on bone growth and development. The aim of this study was to determine whether a procedure using standard T1-weighted magnetic resonance images provides an accurate estimate of bone marrow fat in children with typical development and in children with mild spastic cerebral palsy (CP; n = 15/group; 4–11 y). Magnetic resonance imaging was used to acquire T1-weighted images. It was also used to acquire fat and water images using an iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) technique. Bone marrow fat volume and fat fraction in the middle-third of the tibia were determined using the standard T1-weighted images (BMFVT1 and BMFFT1, respectively) and the fat and water images (BMFVIDEAL and BMFFIDEAL, respectively). In both groups, BMFVT1 was highly correlated with (both r > 0.99, p < 0.001) and not different from (both p > 0.05) BMFVIDEAL. In both groups, BMFFT1 was moderately correlated with (both r = 0.71, p < 0.01) and not different from (both p > 0.05) BMFFIDEAL. There was no group difference in BMFVT1 or BMFVIDEAL (both p > 0.05). BMFFIDEAL was higher in children with CP (p < 0.05), but there was no group difference in BMFFT1 (p > 0.05). We conclude that a procedure using standard T1-weighted magnetic resonance images can produce estimates of bone marrow fat volume similar to estimates from the IDEAL technique in children. However, it is less sensitive to variation in the bone marrow fat fraction.
Efficiency and irreversibility of movements in a city
Authors: Biazzo Indaco , Ramezanpour Abolfazl 
Published: March 2020

AbstractWe know that maximal efficiency in physical systems is attained by reversible processes. It is then interesting to see how irreversibility affects efficiency in other systems, e.g., in a city. In this study, we focus on a cyclic process of movements (home to workplace and back to home) in a city to investigate the above question. To this end, we present a minimal model of the movements, along with plausible definitions for the efficiency and irreversibility of the process; more precisely, we take the inverse of the total travel time per number of trips for efficiency and the relative entropy of the forward and backward flow distributions for the process irreversibility. We perform numerical simulations of the model for reasonable choices of the population distribution, the mobility law, and the movement strategy. The results show that the efficiency of movements is indeed negatively correlated with the above measure of irreversibility. The structure of the network and the impact of the flows on the travel times are the main factors here that affect the time intervals of arriving to destinations and returning to origins, which are usually larger than the time interval of the departures. This in turn gives rise to diverging of the backward flows from the forward ones and results to entropy (disorder or uncertainty) production in the system. The findings of this study might be helpful in characterizing more accurately the city efficiency and in better understanding of the main working principles of these complex systems.
Three-dimensional observation and analysis of remineralization in dentinal caries lesions
Authors: Yoshihara Kumiko , Nagaoka Noriyuki , Nakamura Akiko , Hara Toru , Hayakawa Satoshi , Yoshida Yasuhiro , Van Meerbeek Bart 
Published: March 2020

AbstractThe remineralization mechanism in dental caries lesions is not completely understood. This study reports on ultrastructural and chemical changes observed within arrested caries lesions. Carious human teeth were observed using scanning electron microscopy (SEM) and focused-ion-beam (FIB)-SEM. The crystals detected in the caries lesions were characterized by transmission electron microscopy (TEM), along with chemical element mapping using energy-dispersive spectroscopy (EDS)-STEM. FIB-SEM 3D reconstructions revealed a severely damaged dentin surface abundantly covered by bacteria. Although the dentin tubules were clogged up to a depth of 100 μm, bacterial invasion into dentin tubules was not observed. TEM crystal analysis and EDS-STEM revealed the presence of Ca and P, as well as of Mg within the HAp crystals deposited inside the dentin tubules. It was concluded that extensive remineralization with deposition of Mg-HAp crystals had occurred in dentin tubules of caries-arrested dentin. Understanding the natural remineralization process is thought to be helpful for developing clinical biomimetic remineralization protocols.
Biocompatible Mesoporous Hollow Carbon Nanocapsules for High Performance Supercapacitors
Authors: Wang Lijian , Liu Fenghua , Ning Yuesheng , Bradley Robert , Yang Chengbin , Yong Ken-Tye , Zhao Binyuan , Wu Weiping 
Published: March 2020

AbstractA facile and general method for the controllable synthesis of N-doped hollow mesoporous carbon nanocapsules (NHCNCs) with four different geometries has been developed. The spheres (NHCNC-1), low-concaves (NHCNC-2), semi-concaves (NHCNC-3) and wrinkles (NHCNC-4) shaped samples were prepared and systematically investigated to understand the structural effects of hollow particles on their supercapacitor performances. Compared with the other three different shaped samples (NHCNC-1, NHCNC-2, and NHCNC-4), the as-synthesized semi-concave structured NHCNC-3 demonstrated excellent performance with high gravimetric capacitance of 326 F g−1 (419 F cm−3) and ultra-stable cycling stability (96.6% after 5000 cycles). The outstanding performances achieved are attributed to the unique semi-concave structure, high specific surface area (1400 m2 g−1), hierarchical porosity, high packing density (1.41 g cm−3) and high nitrogen (N) content (up to 3.73%) of the new materials. These carbon nanocapsules with tailorable structures and properties enable them as outstanding carriers and platforms for various emerging applications, such as nanoscale chemical reactors, catalysis, batteries, solar energy harvest, gas storage and so on. In addition, these novel carbons have negligible cytotoxicity and high biocompatibility for human cells, promising a wide range of bio applications, such as biomaterials, drug delivery, biomedicine, biotherapy and bioelectronic devices.
Electrochemical and thermodynamic study on the corrosion performance of API X120 steel in 3.5% NaCl solution
Authors: Shahzad Khuram , Sliem Mostafa H. , Shakoor R. A. , Radwan A. Bahgat , Kahraman Ramazan , Umer Malik Adeel , Manzoor Umair , Abdullah Aboubakr M. 
Published: March 2020

AbstractThe present work studied the effect of temperature on the corrosion behavior of API X120 steel in a saline solution saturated with CO2 in absence and presence of polyethyleneimine (PEI) as an environmentally safe green inhibitor. The effect of PEI on the corrosion behavior of API X120 steel was investigated using destructive and non-destructive electrochemical techniques. The overall results revealed that PEI significantly decreases the corrosion rate of API X120 steel with inhibition efficiency of 94% at a concentration of 100 μmol L−1. The adsorption isotherm, activation energy and the thermodynamic parameters were deduced from the electrochemical results. It is revealed that the adsorption of PEI on API X120 steel surface follows Langmuir adsorption isotherm adopting a Physi-chemisorption mechanism. Finally, the samples were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques to elucidate the effect of aggressiveness of corrosive media on the surface morphology and the corrosion performance of API X120 steel. The surface topography result indicates that the API X120 steel interface in PEI presence is smoother than CO2 with Cl− ions or Cl− ions only. This is attributed to the compact protective film limits the aggressive ions transfer towards the metallic surface and reduces the corrosion rate. Moreover, PEI inhibition mechanism is based on its CO2 capturing ability and the PEI adsorption on the steel surface beside the siderite layer which give the PEI molecules the ability to reduce the scale formation and increase the corrosion protection due to capturing the CO2 from the brine solution.
The Value of Cardiopulmonary Exercise Testing in Determining Severity in Patients with both Systolic Heart Failure and COPD
Authors: Goulart Cássia da Luz , dos Santos Polliana Batista , Caruso Flávia Rossi , Arêas Guilherme Peixoto Tinoco , Marinho Renan Shida , Camargo Patricia de Faria , Alexandre Tiago da Silva , Oliveira Claudio R. , da Silva Andréa Lúcia Gonçalves , Mendes Renata Gonçalves , Roscani Meliza Goi , Borghi-Silva Audrey 
Published: March 2020

AbstractOur aim was to identify optimal cardiopulmonary exercise testing (CPET) threshold values that distinguish disease severity progression in patients with co-existing systolic heart failure (HF) and chronic obstructive pulmonary disease (COPD), and to evaluate the impact of the cut-off determined on the prognosis of hospitalizations. We evaluated 40 patients (30 men and 10 woman) with HF and COPD through pulmonary function testing, doppler echocardiography and maximal incremental CPET on a cycle ergometer. Several significant CPET threshold values were identified in detecting a forced expiratory volume in 1 second (FEV1) < 1.6 L: 1) oxygen uptake efficiency slope (OUES) < 1.3; and 2) circulatory power (CP) < 2383 mmHg.mlO2.kg−1. CPET significant threshold values in identifying a left ventricular ejection fraction (LVEF) < 39% were: 1) OUES: < 1.3; 2) CP < 2116 mmHg.mlO2.kg−1.min−1 and minute ventilation/carbon dioxide production (V̇E/V̇CO2) slope>38. The 15 (38%) patients hospitalized during follow-up (8 ± 2 months). In the hospitalizations analysis, LVEF < 39% and FEV1 < 1.6, OUES < 1.3, CP < 2116 mmHg.mlO2.kg−1.min−1 and V̇E/V̇CO2 > 38 were a strong risk predictor for hospitalization (P ≤ 0.050). The CPET response effectively identified worsening disease severity in patients with a HF-COPD phenotype. LVEF, FEV1, CP, OUES, and the V̇E/V̇CO2 slope may be particularly useful in the clinical assessment and strong risk predictor for hospitalization.
Comparison of several Real-Time PCR Kits versus a Culture-dependent Algorithm to Identify Enteropathogens in Stool Samples
Authors: Valledor Silvia , Valledor Inés , Gil-Rodríguez María Concepción , Seral Cristina , Castillo Javier 
Published: March 2020

AbstractThis study aims to validate the current diagnostic method for the clinical detection of gastroenteritis. We analyzed 400 stool samples to detect three of the most common enteropathogens: Salmonella spp., Campylobacter spp., and Yersinia enterocolitica. All specimens were tested with a routine clinical diagnosis algorithm and with five real-time PCR assays. A total of 98 specimens (24.5%) were positive for enteropathogens. We found 24 samples positive for Salmonella enterica, 71 positive for Campylobacter spp., and 4 positive for Yersinia enterocolitica. All evaluated methods exhibited a good performance in identifying Salmonella and Yersinia enterocolitica, being the highest positive percent agreement (PPA) value of 95.8% and 100%, respectively. The clinical algorithm showed the highest PPA value identifying Salmonella, due to the enrichment in selenite broth. However, the evaluated methods showed notable differences in the identification of Campylobacter species, obtaining a wide range of PPA values: 59.2%–100%. The clinical algorithm showed the lowest PPA value since it was only able to detect Campylobacter jejuni and Campylobacter coli species. This study revealed the importance of implementing the real-time PCR technique in a clinical algorithm: it improved the accuracy of the diagnosis and provided results in a shorter time compared to routine clinical methods.
Neighborhood Preference of Amino Acids in Protein Structures and its Applications in Protein Structure Assessment
Authors: Liu Siyuan , Xiang Xilun , Gao Xiang , Liu Haiguang 
Published: March 2020

AbstractAmino acids form protein 3D structures in unique manners such that the folded structure is stable and functional under physiological conditions. Non-specific and non-covalent interactions between amino acids exhibit neighborhood preferences. Based on structural information from the protein data bank, a statistical energy function was derived to quantify amino acid neighborhood preferences. The neighborhood of one amino acid is defined by its contacting residues, and the energy function is determined by the neighboring residue types and relative positions. The neighborhood preference of amino acids was exploited to facilitate structural quality assessment, which was implemented in the neighborhood preference program NEPRE. The source codes are available via https://github.com/LiuLab-CSRC/NePre.
X-ray Crystallography and Electron Paramagnetic Resonance Spectroscopy Reveal Active Site Rearrangement of Cold-Adapted Inorganic Pyrophosphatase
Authors: Horitani Masaki , Kusubayashi Kazuki , Oshima Kyoka , Yato Akane , Sugimoto Hiroshi , Watanabe Keiichi 
Published: March 2020

AbstractInorganic pyrophosphatase (PPase) catalyses the hydrolysis reaction of inorganic pyrophosphate to phosphates. Our previous studies showed that manganese (Mn) activated PPase from the psychrophilic bacterium Shewanella sp. AS-11 (Mn-Sh-PPase) has a characteristic temperature dependence of the activity with an optimum at 5 °C. Here we report the X-ray crystallography and electron paramagnetic resonance (EPR) spectroscopy structural analyses of Sh-PPase in the absence and presence of substrate analogues. We successfully determined the crystal structure of Mn-Sh-PPase without substrate and Mg-activated Sh-PPase (Mg-Sh-PPase) complexed with substrate analogue (imidodiphosphate; PNP). Crystallographic studies revealed a bridged water placed at a distance from the di-Mn centre in Mn-Sh-PPase without substrate. The water came closer to the metal centre when PNP bound. EPR analysis of Mn-Sh-PPase without substrate revealed considerably weak exchange coupling, whose magnitude was increased by binding of substrate analogues. The data indicate that the bridged molecule has weak bonds with the di-Mn centre, which suggests a ‘loose’ structure, whereas it comes closer to di-Mn centre by substrate binding, which suggests a ‘well-tuned’ structure for catalysis. Thus, we propose that Sh-PPase can rearrange the active site and that the ‘loose’ structure plays an important role in the cold adaptation mechanism.
The effect of synbiotic preparations on the intestinal microbiota and her metabolism in broiler chickens
Authors: Śliżewska Katarzyna , Markowiak-Kopeć Paulina , Żbikowski Artur , Szeleszczuk Piotr 
Published: March 2020

AbstractThe aim of the research was to determine the effect of newly elaborated synbiotic preparations on the count of dominant intestinal microorganisms, on the profile of fatty acids (short chain – SCFA and branched chain – BCFA), the lactic acid produced and the performance of chickens. The studies determined the composition of the dominant intestinal microbiota with use of the culture method. The fatty acid profile was also determined using the high-performance liquid chromatography method (HPLC). Moreover, the performance of chickens was determined such as the daily cumulative mortality rate, the feed conversion ratio (FCR) and the European Production Efficiency Factor (EPEF). It was found that synbiotics had a beneficial effect on parameters of the performance of chickens, and also resulted in increase in the count of beneficial bacteria and to the restriction in growth of potential pathogens in the gastrointestinal tract. Synbiotics caused an increase in the concentration of lactic acid and SCFA and a decrease in the concentration of BCFA in the broiler’s excreta. These results showed a beneficial effect of the tested synbiotics on the intestinal microbiota, their metabolism and the performance of broiler chickens. The elaborated synbiotics can be successfully used as feed additives for broiler chickens.
Replicative conditioning of Herpes simplex type 1 virus by Survivin promoter, combined to ERBB2 retargeting, improves tumour cell-restricted oncolysis
Authors: Sasso Emanuele , Froechlich Guendalina , Cotugno Gabriella , D’Alise Anna Morena , Gentile Chiara , Bignone Veronica , De Lucia Maria , Petrovic Biljana , Campadelli-Fiume Gabriella , Scarselli Elisa , Nicosia Alfredo , Zambrano Nicola 
Published: March 2020

AbstractOncolytic virotherapy is emerging as a promising therapeutic option for solid tumours. Several oncolytic vectors in clinical testing are based on attenuated viruses; thus, efforts are being taken to develop a new repertoire of oncolytic viruses, based on virulent viral genomes. This possibility, however, raises concerns dealing with the safety features of the virulent phenotypes. We generated a double regulatedHerpes simplextype-1 virus (HSV-1), in which tumour cell restricted replicative potential was combined to selective entry via ERBB2 receptor retargeting. The transcriptional control of the viral alpha4 gene encoding for the infected cell protein-4 (ICP4) by the cellular Survivin/BIRC5promoter conferred a tumour cell-restricted replicative potential to a virulent HSV-1 genome. The combination of the additional ERBB2 retargeting further improved the selectivity for tumour cells, conferring to the double regulated virus a very limited ability to infect and propagate in non-cancerous cells. Accordingly, a suitable replicative and cytotoxic potential was maintained in tumour cell lines, allowing the double regulated virus to synergizein vivowith immune checkpoint (anti-PD-1) blockade in immunocompetent mice. Thus, restricting the replicative spectrum and tropism of virulent HSV-1 genomes by combination of conditional replication and retargeting provides an improved safety, does not alter the oncolytic strength, and is exploitable for its therapeutic potential with immune checkpoint blockade in cancer.