bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring dynamic interactions of single nanoparticles at interfaces for surface-confined electrochemical behavior and size measurement
Authors: Ma Hui , Chen Jian-Fu , Wang Hai-Feng , Hu Pei-Jun , Ma Wei , Long Yi-Tao 
Published: May 2020

AbstractWith the development of new instruments and methodologies, the highly dynamic behaviors of nanoparticle at the liquid-solid interface have been studied. However, the dynamic nature of the electrochemical behavior of individual nanoparticles on the electrode interface is still poorly understood. Here, we generalize scaling relations to predict nanoparticle-electrode interactions by examining the adsorption energy of nanoparticles at an ultramicroelectrode interface. Based on the theoretical predictions, we investigate the interaction-modulated dynamic electrochemical behaviors for the oxidation of individual Ag nanoparticles. Typically, significantly distinct current traces are observed owing to the adsorption-mediated motion of Ag nanoparticles. Inspired by restraining the stochastic paths of particles in the vicinity of the electrode interface to produce surface-confined current traces, we successfully realize high-resolution size measurements of Ag nanoparticles in mixed-sample systems. This work offers a better understanding of dynamic interactions of nanoparticles at the electrochemical interface and displays highly valuable applications of single-entity electrochemistry.
Light-powered Escherichia coli cell division for chemical production
Authors: Ding Qiang , Ma Danlei , Liu Gao-Qiang , Li Yang , Guo Liang , Gao Cong , Hu Guipeng , Ye Chao , Liu Jia , Liu Liming , Chen Xiulai 
Published: May 2020

AbstractCell division can perturb the metabolic performance of industrial microbes. The C period of cell division starts from the initiation to the termination of DNA replication, whereas the D period is the bacterial division process. Here, we first shorten the C and D periods of E. coli by controlling the expression of the ribonucleotide reductase NrdAB and division proteins FtsZA through blue light and near-infrared light activation, respectively. It increases the specific surface area to 3.7 μm−1 and acetoin titer to 67.2 g·L−1. Next, we prolong the C and D periods of E. coli by regulating the expression of the ribonucleotide reductase NrdA and division protein inhibitor SulA through blue light activation-repression and near-infrared (NIR) light activation, respectively. It improves the cell volume to 52.6 μm3 and poly(lactate-co-3-hydroxybutyrate) titer to 14.31 g·L−1. Thus, the optogenetic-based cell division regulation strategy can improve the efficiency of microbial cell factories.
Chemical modification of proteins by insertion of synthetic peptides using tandem protein trans-splicing
Authors: Khoo K. K. , Galleano I. , Gasparri F. , Wieneke R. , Harms H. , Poulsen M. H. , Chua H. C. , Wulf M. , Tampé R. , Pless S. A. 
Published: May 2020

AbstractManipulation of proteins by chemical modification is a powerful way to decipher their function. However, most ribosome-dependent and semi-synthetic methods have limitations in the number and type of modifications that can be introduced, especially in live cells. Here, we present an approach to incorporate single or multiple post-translational modifications or non-canonical amino acids into proteins expressed in eukaryotic cells. We insert synthetic peptides into GFP, NaV1.5 and P2X2 receptors via tandem protein trans-splicing using two orthogonal split intein pairs and validate our approach by investigating protein function. We anticipate the approach will overcome some drawbacks of existing protein enigineering methods.
Therapeutic vaccination with IDLV-SIV-Gag results in durable viremia control in chronically SHIV-infected macaques
Authors: Blasi Maria , Wescott Elizabeth C. , Baker Erich J. , Mildenberg Benjamin , LaBranche Celia , Rountree Wes , Haynes Barton F. , Saunders Kevin O. , Moody M. Anthony , Negri Donatella , Santra Sampa , Cara Andrea , Klotman Mary E. 
Published: May 2020

AbstractDespite incredible scientific efforts, there is no cure for HIV infection. While antiretroviral treatment (ART) can help control the virus and prevent transmission, it cannot eradicate HIV from viral reservoirs established before the initiation of therapy. Further, HIV-infected individuals reliably exhibit viral rebound when ART is interrupted, suggesting that the host immune response fails to control viral replication in persistent reservoirs. Therapeutic vaccines are one current approach to improving antiviral host immune responses and enhance long term virus control. In the present study, we used an integrase defective lentiviral vector (IDLV) expressing SIV-Gag to boost anti-Gag specific immune responses in macaques chronically infected with the tier-2 SHIV-1157(QNE)Y173H. A single immunization with IDLV-SIV-Gag induced durable (>20 weeks) virus control in 55% of the vaccinated macaques, correlating with an increased magnitude of SIV-Gag specific CD8+ T-cell responses. IDLV-based therapeutic vaccines are therefore an effective approach to improve virus specific CD8+ T-cell responses and mediate virus control.
Reactants, products, and transition states of elementary chemical reactions based on quantum chemistry
Authors: Grambow Colin A. , Pattanaik Lagnajit , Green William H. 
Published: May 2020

AbstractReaction times, activation energies, branching ratios, yields, and many other quantitative attributes are important for precise organic syntheses and generating detailed reaction mechanisms. Often, it would be useful to be able to classify proposed reactions as fast or slow. However, quantitative chemical reaction data, especially for atom-mapped reactions, are difficult to find in existing databases. Therefore, we used automated potential energy surface exploration to generate 12,000 organic reactions involving H, C, N, and O atoms calculated at the ωB97X-D3/def2-TZVP quantum chemistry level. We report the results of geometry optimizations and frequency calculations for reactants, products, and transition states of all reactions. Additionally, we extracted atom-mapped reaction SMILES, activation energies, and enthalpies of reaction. We believe that this data will accelerate progress in automated methods for organic synthesis and reaction mechanism generation—for example, by enabling the development of novel machine learning models for quantitative reaction prediction.
Post-treatment levels of plasma 25- and 1,25-dihydroxy vitamin D and mortality in men with aggressive prostate cancer
Authors: Nair-Shalliker Visalini , Bang Albert , Egger Sam , Clements Mark , Gardiner Robert A. , Kricker Anne , Seibel Markus J. , Chambers Suzanne K. , Kimlin Michael G. , Armstrong Bruce K. , Smith David P. 
Published: May 2020

AbstractVitamin D may reduce mortality from prostate cancer (PC). We examined the associations of post-treatment plasma 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D concentrations with PC mortality. Participants were PC cases from the New South Wales Prostate Cancer Care. All contactable and consenting participants, at 4.9 to 8.6 years after diagnosis, were interviewed and had plasma 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) measured in blood specimens. Cox regression allowing for left-truncation was used to calculate adjusted mortality hazards ratios (HR) and 95% confidence intervals (95% CI) for all-cause and PC-specific mortality in relation to vitamin D levels and other potentially-predictive variables. Of the participants (n = 111; 75·9% response rate), there were 198 deaths from any cause and 41 from PC in the study period. Plasma 25(OH)D was not associated with all-cause or PC-specific mortality (p-values > 0·10). Plasma 1,25(OH)2D was inversely associated with all-cause mortality (HR for highest relative to lowest quartile = 0·45; 95% CI: 0·29–0·69), and PC-specific mortality (HR = 0·40; 95% CI: 0·14–1·19). These associations were apparent only in men with aggressive PC: all-cause mortality HR = 0·28 (95% CI·0·15–0·52; p-interaction = 0·07) and PC-specific mortality HR = 0·26 (95% CI: 0·07–1.00). Time spent outdoors was also associated with lower all-cause (HR for 4th relative to 1st exposure quartile = 0·42; 95% CI: 0·24–0·75) and PC-specific (HR = 0·48; 95% CI: 0·14–1·64) mortality, although the 95% CI for the latter was wide. The inverse association between post-treatment plasma 1,25(OH)2D levels and all-cause and PC-specific mortality in men with aggressive PC, suggest a possible beneficial effect of vitamin D supplementation in these men.
Mutualistic cross-feeding in microbial systems generates bistability via an Allee effect
Authors: Vet Stefan , Gelens Lendert , Gonze Didier 
Published: May 2020

AbstractIn microbial ecosystems, species not only compete for common resources but may also display mutualistic interactions as a result from metabolic cross-feeding. Such mutualism can lead to bistability. Depending on the initial population sizes, species will either survive or go extinct. Various phenomenological models have been suggested to describe bistability in mutualistic systems. However, these models do not account for interaction mediators such as nutrients. In contrast, nutrient-explicit models do not provide an intuitive understanding of what causes bistability. Here, we reduce a theoretical nutrient-explicit model of two mutualistic cross-feeders in a chemostat, uncovering an explicit relation to a growth model with an Allee effect. We show that the dilution rate in the chemostat leads to bistability by turning a weak Allee effect into a strong Allee effect. This happens as long as there is more production than consumption of cross-fed nutrients. Thanks to the explicit relationship of the reduced model with the underlying experimental parameters, these results allow to predict the biological conditions that sustain or prevent the survival of mutualistic species.
Assessment of soil fertility and potato crop nutrient status in central and eastern highlands of Kenya
Authors: Mugo James. N. , Karanja Nancy N. , Gachene Charles K. , Dittert Klaus , Nyawade Shadrack O. , Schulte-Geldermann Elmar 
Published: May 2020

AbstractInherent low soil fertility remains a hindrance to potato production in Kenya and continues to pose a threat to food security. A study was conducted in Nyandarua and Meru counties to assess the soil fertility status in smallholder potato farms. Soil and plant tissue samples were collected and analysed for selected nutrients (pH, OC, N, P, K, S, Ca, Mg, Zn, B and Cu) from 198 farms. Critical nutrient levels were used to assess the sufficiency levels of nutrients for potato growth. Soils in the sampled farms were weakly to strongly acidic (pH-CaCl2 3.9–6.6) and had low to high soil organic matter content (1.5–97.5 g Kg−1). The percent of farms in Meru and Nyandarua with nutrient contents below critical levels were 66% and 20% for N, 46% and 85% for P, 67% and 31% for S, 9% and 51% for Cu, and 87% and 80% for B, respectively. Low tissue nutrient concentrations were observed for N, P, K, and S irrespective of the sites. Soil pH correlated strongly with majority of the analyzed soil and tissue nutrients. These results affirm the need to design integrative soil fertility management strategies to correct the impoverished soil fertility status in the study area.
Differentiation of Hispanic biogeographic ancestry with 80 ancestry informative markers
Authors: Setser Casandra H. , Planz John V. , Barber Robert C. , Phillips Nicole R. , Chakraborty Ranajit , Cross Deanna S. 
Published: May 2020

AbstractAncestry informative single nucleotide polymorphisms (SNPs) can identify biogeographic ancestry (BGA); however, population substructure and relatively recent admixture can make differentiation difficult in heterogeneous Hispanic populations. Utilizing unrelated individuals from the Genomic Origins and Admixture in Latinos dataset (GOAL, n = 160), we designed an 80 SNP panel (Setser80) that accurately depicts BGA through STRUCTURE and PCA. We compared our Setser80 to the Seldin and Kidd panels via resampling simulations, which models data based on allele frequencies. We incorporated Admixed American 1000 Genomes populations (1000 G, n = 347), into a combined populations dataset to determine robustness. Using multinomial logistic regression (MLR), we compared the 3 panels on the combined dataset and found overall MLR classification accuracies: 93.2% Setser80, 87.9% Seldin panel, 71.4% Kidd panel. Naïve Bayesian classification had similar results on the combined dataset: 91.5% Setser80, 84.7% Seldin panel, 71.1% Kidd panel. Although Peru and Mexico were absent from panel design, we achieved high classification accuracy on the combined populations for Peru (MLR = 100%, naïve Bayes = 98%), and Mexico (MLR = 90%, naïve Bayes = 83.4%) as evidence of the portability of the Setser80. Our results indicate the Setser80 SNP panel can reliably classify BGA for individuals of presumed Hispanic origin.
Generation of few-cycle multi-millijoule 2.5 μm pulses from a single-stage Cr2+:ZnSe amplifier
Authors: Wu Yi , Zhou Fangjie , Larsen Esben W. , Zhuang Fengjiang , Yin Yanchun , Chang Zenghu 
Published: May 2020

AbstractLasers capable of generating attosecond X-ray pulses in the water window (282 to 533 eV) through high-order harmonic generation are normally based on inefficient, multi-stage optical parametric amplifiers or optical parametric chirped pulse amplifiers pumped by femtosecond or picosecond lasers. Here we report a very efficient single amplification stage laser based on traditional chirped pulse amplification capable of producing 4 mJ, near-transform limited 44 fs (<6 cycles), 1 kHz pulses centered at 2.5 μm. The ≈90 GW peak power is the highest value ever reached at this wavelength. In order to fully compress the laser pulses our system is built in a nitrogen box. Our system utilizes water cooled chromium doped zinc selenide (Cr2+:ZnSe) as the gain medium and is pumped by a commercial nanosecond holmium doped yttrium-aluminum-garnet (Ho:YAG) laser.
Trait impulsivity and acute stress interact to influence choice and decision speed during multi-stage decision-making
Authors: Raio Candace M. , Konova Anna B. , Otto A. Ross 
Published: May 2020

AbstractImpulsivity and stress exposure are two factors that are associated with changes in reward-related behavior in ways that are relevant to both healthy and maladaptive decision-making. Nonetheless, little empirical work has examined the possible independent and joint effects of these factors upon reward learning. Here, we sought to examine how trait impulsivity and acute stress exposure affect participants’ choice behavior and decision speed in a two-stage sequential reinforcement-learning task. We found that more impulsive participants were more likely to repeat second-stage choices after previous reward, irrespective of stress condition. Exposure to stress, on the other hand, was associated with an increased tendency to repeat second-stage choices independent of whether these choices previously led to a reward, and this tendency was exacerbated in more impulsive individuals. Such interaction effects between stress and impulsivity were also found on decision speed. Stress and impulsivity levels interacted to drive faster choices overall (again irrespective of reward) at both task stages, while reward received on the previous trial slowed subsequent first-stage choices, particularly among impulsive individuals under stress. Collectively, our results reveal novel, largely interactive effects of trait impulsivity and stress exposure and suggest that stress may reveal individual differences in decision-making tied to impulsivity that are not readily apparent in the absence of stress.
Surgical Outcomes of Patients with Diagnostic Preoperative Monocular Occlusion in Intermittent Exotropia
Authors: Lee Jin Young , Song Ji Eun , Chang Hae Ran , Choi Chul Young , Han So Young 
Published: May 2020

AbstractWe evaluated surgical outcomes of bilateral rectus (BLR) recession in patients with intermittent exotropia who underwent diagnostic monocular occlusion. Records of patients with intermittent exotropia who were preoperatively examined one-hour monocular occlusion and underwent BLR recession were reviewed retrospectively. Patients were classified into two groups based on change in exodeviation angle: responders (≥5 change in prism diopters [PD] after occlusion) or non-responders (<5 PD change after occlusion). BLR recession amount was determined by maximal angle deviation after occlusion tests in both groups. Overall follow-up period was 38.81 ± 24.09 months for non-responders (n = 106) and 38.52 ± 19.87 months for responders (n = 142) (p = 0.766). There was no difference in deviation before monocular occlusion between the two groups. Mean angle of deviation at distance (24.23 ± 6.27 PD) and near fixation (25.46 ± 6.78 PD) increased to distance (29.95 ± 6.43 PD) and near deviation (32.15 ± 6.17 PD) after occlusion in the responder group. At postoperative 1 year, surgical success rate was higher in responders (71.1%) than in non-responders (52.8%) (p = 0.003). Kaplan-Meier survival analysis revealed significantly higher surgical success in responders (p = 0.001, log-rank test). Preoperative diagnostic monocular occlusion in patients with intermittent exotropia can influence surgical outcomes by identifying the latent exodeviation angle.
Cork oak and climate change: Disentangling drought effects on cork chemical composition
Authors: Leite Carla , Oliveira Vanda , Miranda Isabel , Pereira Helena 
Published: May 2020

AbstractClimate change induces in the Mediterranean region more frequent and extreme events, namely, heat waves and droughts, disturbing forest species and affecting their productivity and product quality. The cork oak (Quercus suber) is present along the western Mediterranean basin and its outer bark (cork) is sustainably collected and used for several products, mainly wine bottle stoppers. Since most cork properties arise from its chemical composition, this research studies the effect of drought on cork chemical composition (suberin, lignin, polysaccharides and extractives) and on polysaccharide and suberin monomeric composition. Three sets of cork samples, from the same site, were examined: in one set the cork grew without drought; in another two drought events occurred during cork growth and in the third one drought event happened. The results show that, in general, drought does not affect the proportion of the main components of cork, the monomers of suberin or of polysaccharides, with few exceptions e.g. drought increased ethanol extractives and xylose in polysaccharides and decreased arabinose in polysaccharides. The variability associated to the tree is much more relevant than the effect of drought conditions and affects all the parameters analyzed. Therefore, our research suggests that the tree genetic information, or its expression, plays a much more important role on the chemical composition of cork than the drought conditions occurring during cork growth. In practical terms, the potential increased occurrence of droughts arising from climatic changes will not compromise the performance of cork as a sealant for wine bottles.
Feasibility between Bifidobacteria Targeting and Changes in the Acoustic Environment of tumor Tissue for Synergistic HIFU
Authors: Xu Die , Zou Wenjuan , Luo Yong , Gao Xuan , Jiang Binglei , Wang Yaotai , Jiang Fujie , Xiong Jie , Chen Chun , Tang Yu , Qiao Hai , Li Huanan , Zou Jianzhong 
Published: May 2020

AbstractHigh intensity focused ultrasound (HIFU) has been recently shown as a rapidly developing new technique for non-invasive ablation of local tumors whose therapeutic efficiency can be significantly improved by changing the tissue acoustic environment (AET). Currently, the method of changing AET is mainly to introduce a medium with high acoustic impedance, but there are some disadvantages such as low retention of the introduced medium in the target area and a short residence time during the process. In our strategy, anaerobic bacterium Bifidobacterium longum (B. longum) which can colonize selectively in hypoxic regions of the animal body was successfully localized and shown to proliferate in the hypoxic zone of tumor tissue, overcoming the above disadvantages. This study aimed to explore the effects of Bifidobacteria on AET (including the structure and acoustic properties of tumor tissues) and HIFU ablation at different time. The results show that the injection of Bifidobacteria increased the collagen fibre number, elastic modulus and sound velocity and decreased neovascularization in tumor tissues. The number of collagen fibres and neovascularization decreased significantly over time. Under the same HIFU irradiation intensity, the B. longum injection increased the coagulative necrosis volume and decreased the energy efficiency factor (EEF). This study confirmed that Bifidobacteria can change the AET and increase the deposition of ultrasonic energy and thereby the efficiency of HIFU. In addition, the time that Bifidobacteria stay in the tumor area after injection is an important factor. This research provides a novel approach for synergistic biologically targeted HIFU therapy.
Neurocognitive mechanisms underlying working memory encoding and retrieval in Attention-Deficit/Hyperactivity Disorder
Authors: Ortega Rodrigo , López Vladimir , Carrasco Ximena , Escobar María Josefina , García Adolfo M. , Parra Mario A. , Aboitiz Francisco 
Published: May 2020

AbstractWorking memory (WM) impairments in ADHD have been consistently reported along with deficits in attentional control. Yet, it is not clear which specific WM processes are affected in this condition. A deficient coupling between attention and WM has been reported. Nevertheless, most studies focus on the capacity to retain information rather than on the attention-dependent stages of encoding and retrieval. The current study uses a visual short-term memory binding task, measuring both behavioral and electrophysiological responses to characterize WM encoding, binding and retrieval comparing ADHD and non-ADHD matched adolescents. ADHD exhibited poorer accuracy and larger reaction times than non-ADHD on all conditions but especially when a change across encoding and test displays occurred. Binding manipulation affected equally both groups. Encoding P3 was larger in the non-ADHD group. Retrieval P3 discriminated change only in the non-ADHD group. Binding-dependent ERP modulations did not reveal group differences. Encoding and retrieval P3 were significantly correlated only in non-ADHD. These results suggest that while binding processes seem to be intact in ADHD, attention-related encoding and retrieval processes are compromised, resulting in a failure in the prioritization of relevant information. This new evidence can also inform recent theories of binding in visual WM.