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Bin Du, Bihua Cao, Weiqi He, Fuhong Li
The ability to learn from feedback is important for children's adaptive behavior and school learning. Feedback has two main components, informative value and valence. How to disentangle these two components and what is the developmental neural correlates of using the informative value of feedback is still an open question. In this study, 23 children (7-10 years old) and 19 adults (19-22 years old) were asked to perform a rule induction task, in which they were required to find a rule, based on the informative value of feedback...
2018: Frontiers in Psychology
Roshan A Karunamuni, Joshua Kuperman, Tyler M Seibert, Natalie Schenker, Rebecca Rakow-Penner, V S Sundar, Jose R Teruel, Pal E Goa, David S Karow, Anders M Dale, Nathan S White
Background High b-value diffusion-weighted imaging has application in the detection of cancerous tissue across multiple body sites. Diffusional kurtosis and bi-exponential modeling are two popular model-based techniques, whose performance in relation to each other has yet to be fully explored. Purpose To determine the relationship between excess kurtosis and signal fractions derived from bi-exponential modeling in the detection of suspicious prostate lesions. Material and Methods This retrospective study analyzed patients with normal prostate tissue (n = 12) or suspicious lesions (n = 13, one lesion per patient), as determined by a radiologist whose clinical care included a high b-value diffusion series...
January 1, 2018: Acta Radiologica
Amin J Barakat, Margarita Raygada, Owen M Rennert
Barakat syndrome also known as HDR syndrome (Online Mendelian Inheritance in Man [OMIM] 146255), was first described by Barakat et al. in . It is a rare genetic disorder characterized by the triad of hypoparathyroidism "H," sensorineural deafness "D," and renal disease "R." The defect is caused by deletions in chromosome 10p14 or mutations in the GATA3 gene. Although the syndrome has been phenotypically defined by this triad the literature identifies cases with different components with, or without GATA3 defects making the definition of the syndrome confusing...
April 16, 2018: American Journal of Medical Genetics. Part A
Huan Li, Feng Liu, Wei Peng, Kang Yan, Haixu Zhao, Ting Liu, Hui Cheng, Peixi Chang, Fangyan Yuan, Huanchun Chen, Weicheng Bei
Gram-negative bacteria have evolved numerous two-component systems (TCSs) to cope with external environmental changes. The CpxA/CpxR TCS consisting of the kinase CpxA and the regulator CpxR, is known to be involved in the biofilm formation and virulence of Escherichia coli . However, the role of CpxA/CpxR remained unclear in Actinobacillus pleuropneumoniae , a bacterial pathogen that can cause porcine contagious pleuropneumonia (PCP). In this report, we show that CpxA/CpxR contributes to the biofilm formation ability of A...
2018: Frontiers in Cellular and Infection Microbiology
Li Zhang, Jun Ding, Hanyu Zheng, Sensong An, Hongtao Lin, Bowen Zheng, Qingyang Du, Gufan Yin, Jerome Michon, Yifei Zhang, Zhuoran Fang, Mikhail Y Shalaginov, Longjiang Deng, Tian Gu, Hualiang Zhang, Juejun Hu
The mid-infrared (mid-IR) is a strategically important band for numerous applications ranging from night vision to biochemical sensing. Here we theoretically analyzed and experimentally realized a Huygens metasurface platform capable of fulfilling a diverse cross-section of optical functions in the mid-IR. The meta-optical elements were constructed using high-index chalcogenide films deposited on fluoride substrates: the choices of wide-band transparent materials allow the design to be scaled across a broad infrared spectrum...
April 16, 2018: Nature Communications
Cinta Gomez-Silvan, Marcus H Y Leung, Katherine A Grue, Randeep Kaur, Xinzhao Tong, Patrick K H Lee, Gary L Andersen
BACKGROUND: A majority of indoor residential microbes originate from humans, pets, and outdoor air and are not adapted to the built environment (BE). Consequently, a large portion of the microbes identified by DNA-based methods are either dead or metabolically inactive. Although many exceptions have been noted, the ribosomal RNA fraction of the sample is more likely to represent either viable or metabolically active cells. We examined methodological variations in sample processing using a defined, mock BE microbial community to better understand the scope of technique-based vs...
April 16, 2018: Microbiome
Bardia Nouriziabari, Susmita Sarkar, Stephanie E Tanninen, Robert D Dayton, Ronald L Klein, Kaori Takehara-Nishiuchi
Trace eyeblink conditioning is a hippocampus-dependent associative learning paradigm which is impaired in patients with Alzheimer's disease (AD) and animal AD models. Learning in this paradigm accompanies changes in oscillatory activity in forebrain regions, some of which are loci of pathogenic changes in prodromal AD stages. These observations motivated us to examine how cortical event-related potentials (ERPs) during this paradigm are affected by two features of the asymptomatic, AD-related brain abnormality, entorhinal tau accumulation and mild cholinergic deficit...
April 11, 2018: Journal of Alzheimer's Disease: JAD
Iqbal Ahmad, Muhammad Furqan Mobeen, Muhammad Ali Sheraz, Sofia Ahmed, Zubair Anwar, Ruby Saeed Shaikh, Imtiaz Hussain, Saiyed Muhammad Ali
The photodegradation of ascorbic acid (AH2 ) in the presence of nicotinamide (NA) at pH 2.0-12.0 has been studied using a 30 W UV radiation source. The reaction follows first-order kinetics and the values of apparent first-order rate constants (kobs ) at 1 × 10-3  M NA concentration range from 1.17 (pH 2.0) to 3.61 × 10-3  min-1 (pH 12.0). The values of these rate constants (k0 ) in the absence of NA range from 0.50 (pH 2.0) to 1.75 × 10-3  min-1 (pH 12.0), indicating that the values of kobs for the photodegradation of AH2 in the presence of NA are about 2 fold compared to those of the AH2 alone...
April 8, 2018: Journal of Photochemistry and Photobiology. B, Biology
Partha Pratim Pal, S Ramakrishna, Tamar Seideman
The Landauer expression for computing current-voltage characteristics in nanoscale devices is efficient but not suited to transient phenomena and a time-dependent current because it is applicable only when the charge carriers transition into a steady flux after an external perturbation. In this article, we construct a very general expression for time-dependent current in an electrode-molecule-electrode arrangement. Utilizing a model Hamiltonian (consisting of the subsystem energy levels and their electronic coupling terms), we propagate the Schrödinger wave function equation to numerically compute the time-dependent population in the individual subsystems...
April 14, 2018: Journal of Chemical Physics
Junzi Liu, Lan Cheng
An atomic mean-field (AMF) spin-orbit (SO) approach within exact two-component theory (X2C) is reported, thereby exploiting the exact decoupling scheme of X2C, the one-electron approximation for the scalar-relativistic contributions, the mean-field approximation for the treatment of the two-electron SO contribution, and the local nature of the SO interactions. The Hamiltonian of the proposed SOX2CAMF scheme comprises the one-electron X2C Hamiltonian, the instantaneous two-electron Coulomb interaction, and an AMF SO term derived from spherically averaged Dirac-Coulomb Hartree-Fock calculations of atoms; no molecular relativistic two-electron integrals are required...
April 14, 2018: Journal of Chemical Physics
Lisa Gottschlich, Miriam Bortfeld-Miller, Christoph Gäbelein, Sebastian Dintner, Julia A Vorholt
Two-component systems constitute phosphotransfer signaling pathways and enable adaptation to environmental changes, an essential feature for bacterial survival. The general stress response (GSR) in the plant-protecting alphaproteobacterium Sphingomonas melonis Fr1 involves a two-component system consisting of multiple stress-sensing histidine kinases (Paks) and the response regulator PhyR; PhyR in turn regulates the alternative sigma factor EcfG, which controls expression of the GSR regulon. While Paks had been shown to phosphorylate PhyR in vitro, it remained unclear if and under which conditions direct phosphorylation happens in the cell, as Paks also phosphorylate the single domain response regulator SdrG, an essential yet enigmatic component of the GSR signaling pathway...
April 2018: PLoS Genetics
David J Glugla, Madeline B Chosy, Marvin D Alim, Kimberly K Childress, Amy C Sullivan, Robert R McLeod
We demonstrate that multiple exposures of a two-component holographic photopolymer can quadruple the refractive index contrast of the material beyond the single-exposure saturation limit. Quantitative phase microscopy of isolated structures written by laser direct-write lithography is used to characterize the process. This technique reveals that multiple exposures are made possible by diffusion of the chemical components consumed during writing into the previously exposed regions. The ultimate index contrast is shown to be limited by the solubility of fresh components into the multiply exposed region...
April 15, 2018: Optics Letters
Martyn Dade-Robertson, Helen Mitrani, Javier Rodriguez Corral, Meng Zhang, Luis Hernan, Aurelie Guyet, Anil Wipat
In this paper, we describe the first steps in the design of a synthetic biological system based on the use of genetically modified bacteria to detect elevated pressures in soils and respond by cementing soil particles. Such a system might, for example, enable a self- constructed foundation to form in response to load using engineered bacteria which could be seeded and grown in the soils. This process would reduce the need for large-scale excavations and may be the basis for a new generation of self-assembling and responsive bio-based materials...
April 13, 2018: Bioinspiration & Biomimetics
Brian P Landry, Rohan Palanki, Nikola Dyulgyarov, Lucas A Hartsough, Jeffrey J Tabor
Two-component systems (TCSs) are the largest family of multi-step signal transduction pathways in biology, and a major source of sensors for biotechnology. However, the input concentrations to which biosensors respond are often mismatched with application requirements. Here, we utilize a mathematical model to show that TCS detection thresholds increase with the phosphatase activity of the sensor histidine kinase. We experimentally validate this result in engineered Bacillus subtilis nitrate and E. coli aspartate TCS sensors by tuning their detection threshold up to two orders of magnitude...
April 12, 2018: Nature Communications
Weihua Wang, Alexander Kevin Zinsmaier, Ethan Firestone, Ruizhu Lin, Tatiana A Yatskievych, Sungchil Yang, Jinsheng Zhang, Shaowen Bao
Traumatic brain injury (TBI) is a major cause of neurological disorder and death in civilian and military populations (citation?). It comprises two components-direct injury from the traumatic impact and secondary injury from ensuing neural inflammatory responses. Blocking tumor necrosis factor-alpha (TNF-α), a central regulator of neural inflammation, has been shown to improve functional recovery after TBI. However, the mechanisms underlying those therapeutic effects are still poorly understood. Here we examined effects of 3,6'-dithiothalidomide (dTT), a potentially therapeutic TNF-α inhibitor, in mice with blast-induced TBI...
April 13, 2018: Journal of Neurotrauma
Yi Chen, Hui Zhang, Wenzhao Zhou, Chao Deng, Jian Liao
This study set out with the aim of investigating the solvent effects on dimethyl phthalate (DMP) using FTIR characterization, solvent parameter correlation and DFT calculation. DMP exposed to 17 organic solvents manifested varying shift in the carbonyl stretching vibration frequency (νCO ). Non-alkanols induced Band I and alkanols produced Band I and Band II. Through correlating the νCO with the empirical solvent scales including acceptor parameter (AN), Schleyer's linear free energy parameter (G), and linear free salvation energy relationships (LSER), Band I was mainly ascribed to non-specific effects from either non-alkanols or alkanol polymers ((alkanol)n )...
April 3, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Jian-Geng Chiou, Samuel A Ramirez, Timothy C Elston, Thomas P Witelski, David G Schaeffer, Daniel J Lew
Rho-GTPases are master regulators of polarity establishment and cell morphology. Positive feedback enables concentration of Rho-GTPases into clusters at the cell cortex, from where they regulate the cytoskeleton. Different cell types reproducibly generate either one (e.g. the front of a migrating cell) or several clusters (e.g. the multiple dendrites of a neuron), but the mechanistic basis for unipolar or multipolar outcomes is unclear. The design principles of Rho-GTPase circuits are captured by two-component reaction-diffusion models based on conserved aspects of Rho-GTPase biochemistry...
April 12, 2018: PLoS Computational Biology
R Semino, J C Moreton, N A Ramsahye, S M Cohen, G Maurin
The microscopic interfacial structures for a series of metal-organic framework/polymer composites consisting of the Zr-based UiO-66 coupled with different polymers are systematically explored by applying a computational methodology that integrates density functional theory calculations and force field-based molecular dynamics simulations. These predictions are correlated with experimental findings to unravel the structure-compatibility relationship of the MOF/polymer pairs. The relative contributions of the intermolecular MOF/polymer interactions and the flexibility/rigidity of the polymer with respect to the microscopic structure of the interface are rationalized, and their impact on the compatibility of the two components in the resulting composite is discussed...
January 14, 2018: Chemical Science
Michiyo Matsumoto-Nakano
Streptococcus mutans has been implicated as a primary causative agent of dental caries in humans. An important virulence property of the bacterium is its ability to form biofilm known as dental plaque on tooth surfaces. In addition, this organism also produces glucosyltransferases, multiple glucan-binding proteins, protein antigen c, and collagen-binding protein, surface proteins that coordinate to produce dental plaque, thus inducing dental caries. Bacteria utilize quorum-sensing systems to modulate environmental stress responses...
February 2018: Japanese Dental Science Review
Elisabeth Tamayo, Simon A B Knight, Ascensión Valderas, Andrew Dancis, Nuria Ferrol
Arbuscular mycorrhizal (AM) fungi can improve iron (Fe) acquisition of their host plants. Here, we report a characterization of two components of the high-affinity reductive Fe uptake system of Rhizophagus irregularis, the ferric reductase (RiFRE1) and the high affinity Fe permeases (RiFTR1-2). In the extraradical mycelia (ERM), Fe deficiency induced activation of a plasma membrane-localized ferric reductase, an enzyme that reduces Fe(III) sources to the more soluble Fe(II). Yeast mutant complementation assays showed that RiFRE1 encodes a functional ferric reductase and RiFTR1 an iron permease...
April 6, 2018: Environmental Microbiology
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