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System dynamics

Michael K Yeung, Sophia L Sze, Jean Woo, Timothy Kwok, David H K Shum, Ruby Yu, Agnes S Chan
BACKGROUND: Some functional magnetic resonance imaging studies have reported altered activations in the frontal cortex during working memory (WM) performance in individuals with mild cognitive impairment (MCI), but the findings have been mixed. The objective of the present study was to utilize near-infrared spectroscopy (NIRS), an alternative imaging technique, to examine neural processing during WM performance in individuals with MCI. METHODS: Twenty-six older adults with MCI (7 males; mean age 69...
October 27, 2016: Dementia and Geriatric Cognitive Disorders
Michael D Besmer, Frederik Hammes
Short-term fluctuations in bacterial concentrations in drinking water systems, occurring on time scales of hours-to-weeks, are essentially unexplored due to a lack of microbial monitoring tools that allow high frequency measurements. Here, we applied fully automated online flow cytometry to measure the total cell concentrations (TCC) in both raw water (karstic groundwater) and treated water (flocculation - ultrafiltration (UF) - ozonation - granular active carbon (GAC) filtration) during a period of 70 days at high temporal resolution (n > 4000 for both water types)...
October 18, 2016: Water Research
Rene Daer, Josh P Cutts, David A Brafman, Karmella A Haynes
In order to efficiently edit eukaryotic genomes, it is critical to test the impact of chromatin dynamics on CRISPR/Cas9 function and develop strategies to adapt the system to eukaryotic contexts. So far, research has extensively characterized the relationship between the CRISPR endonuclease Cas9 and the composition of the RNA-DNA duplex that mediates the system's precision. Evidence suggests that chromatin modifications and DNA packaging can block eukaryotic genome editing by custom-built DNA endonucleases like Cas9; however, the underlying mechanism of Cas9 inhibition is unclear...
October 26, 2016: ACS Synthetic Biology
Mércia Mascarenhas Fernandes Cerqueira, Rafanielly de Oliveira Alves, Maria Geralda Gomes Aguiar
The scope of this study is to describe the experiences of mothers of children with intellectual disabilities who have been treated in a specialized institution in Feira de Santana, State of Bahia, during their therapeutic itineraries. The study adopted a qualitative approach and was conducted by means of semi-structured interviews. The results revealed that the discovery that their child has an intellectual disability is accepted by their mothers with emotions of shock, denial, anger, negotiation, depression and subsequent acceptance...
October 2016: Ciência & Saúde Coletiva
André David Kovac, Maximilian Koall, Gordon Pipa, Hazem Toutounji
Delays are ubiquitous in biological systems, ranging from genetic regulatory networks and synaptic conductances, to predator/pray population interactions. The evidence is mounting, not only to the presence of delays as physical constraints in signal propagation speed, but also to their functional role in providing dynamical diversity to the systems that comprise them. The latter observation in biological systems inspired the recent development of a computational architecture that harnesses this dynamical diversity, by delay-coupling a single nonlinear element to itself...
2016: PloS One
James S Pryke, Francois Roets, Michael J Samways
Southern Africa's grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects...
2016: PloS One
Alireza Mashaghi, Sergey Bezrukavnikov, David P Minde, Anne S Wentink, Roman Kityk, Beate Zachmann-Brand, Matthias P Mayer, Günter Kramer, Bernd Bukau, Sander J Tans
The Hsp70 system is a central hub of chaperone activity in all domains of life. Hsp70 performs a plethora of tasks, including folding assistance, protection against aggregation, protein trafficking, and enzyme activity regulation, and interacts with non-folded chains, as well as near-native, misfolded, and aggregated proteins. Hsp70 is thought to achieve its many physiological roles by binding peptide segments that extend from these different protein conformers within a groove that can be covered by an ATP-driven helical lid...
October 26, 2016: Nature
Andrew B Rosenkrantz, James S Babb, Samir S Taneja, Justin M Ream
Purpose To test the impact of existing Prostate Imaging Reporting and Data System (PI-RADS) version 2 (V2) decision rules, as well as of proposed adjustments to these decision rules, on detection of Gleason score (GS) 7 or greater (GS ≥7) prostate cancer. Materials and Methods Two radiologists independently provided PI-RADS V2 scores for the dominant lesion on 343 prostate magnetic resonance (MR) examinations. Diagnostic performance for GS ≥7 tumor was assessed by using MR imaging-ultrasonography fusion-targeted biopsy as the reference...
October 26, 2016: Radiology
Sheng-Heng Chung, Chi-Hao Chang, Arumugam Manthiram
Sulfur exhibits a high theoretical capacity of 1,675 mA h g-1 via a distinct conversion reaction, which is different from the insertion reactions in commercial lithium-ion batteries. In consideration of its conversion-reaction battery chemistry, a custom design for electrode materials could establish the way for attaining high-loading capability while simultaneously maintaining high electrochemical utilization and stability. In this study, this process is undertaken by introducing carbon cotton as an attractive electrode-containment material for enhancing the dynamic and static stabilities of lithium-sulfur (Li-S) batteries...
October 26, 2016: ACS Nano
Jung Jae Park, Byung Kwan Park
PURPOSE: To evaluate the role of Prostate Imaging Reporting and Data System v. 2 (PI-RADSv2) in triaging patients with prostate cancer according to Prostate Cancer Research International: Active Surveillance (PRIAS). MATERIALS AND METHODS: Between January 2012 and December 2014, 456 patients with biopsy-proven cancer underwent multiparametric 3T magnetic resonance imaging (MRI) using T2 -weighted, diffusion-weighted, and dynamic contrast-enhanced MRI sequences, and then radical prostatectomy...
October 26, 2016: Journal of Magnetic Resonance Imaging: JMRI
Burcin Yavuz, Uday B Kompella
Although the eye is an accessible organ for direct drug application, ocular drug delivery remains a major challenge due to multiple barriers within the eye. Key barriers include static barriers imposed by the cornea, conjunctiva, and retinal pigment epithelium and dynamic barriers including tear turnover and blood and lymphatic clearance mechanisms. Systemic administration by oral and parenteral routes is limited by static blood-tissue barriers that include epithelial and endothelial layers, in addition to rapid vascular clearance mechanisms...
October 26, 2016: Handbook of Experimental Pharmacology
Praveenkumar Sappidi, Upendra Natarajan
The intermolecular structure and solvation enthalpy of anionic polyelectrolyte atactic Na(+)-polyethacrylate (PEA) in aqueous solution, as a function of added salt concentration C s (dilute to concentrated) and valency (NaCl versus CaCl2), were investigated via molecular dynamics simulations with explicit-ion-solvent and atomistic polymer description. An increase in C s leads to a decrease in α, which stabilizes to a constant value beyond critical C s. A significant reduction in R g in the presence of CaCl2 salt was observed, due to ion bridging of PEA by Ca(2+) ions, in agreement with results available in literature on other similar polycarboxylates...
November 2016: Journal of Molecular Modeling
Wang Heping, Geng Xingguo, Li Xiaoguang, Zang Duyang
This paper presents an exploration of the separation behavior and pattern formation in a shear binary fluid with dynamic temperature after slow cooling via coupled lattice Boltzmann method. The phase separation procedure can be divided into three different stages: spinodal decomposition, domain growth, and domain stretch. The effect of thermal diffusion was observed to be more significant than that of shear convection in the spinodal decomposition stage, while the opposite was observed in the domain growth stage...
October 2016: European Physical Journal. E, Soft Matter
Jennifer Hochheim, Angela Kranz, Karin Krumbach, Sascha Sokolowsky, Lothar Eggeling, Stephan Noack, Marco Bocola, Michael Bott, Jan Marienhagen
OBJECTIVES: To explore systemic effects of mutations in the UDP-N-acetylmuramoylalanyl-D-glutamate 2,6-diaminopimelate ligase (MurE) of Corynebacterium glutamicum, that leads to extracellular L-lysine accumulation by this bacterium. RESULTS: The analysis of a mutant cohort of C. glutamicum strains carrying all possible 20 amino acids at position 81 of MurE revealed unexpected effects on cellular properties. With increasing L-lysine accumulation the growth rate of the producing strain is reduced...
October 25, 2016: Biotechnology Letters
Slavica Pavlov-Dolijanovic, Nebojsa Petrovic, Nada Vujasinovic Stupar, Nemanja Damjanov, Goran Radunovic, Dragan Babic, Dragana Sobic-Saranovic, Vera Artiko
We assess the usefulness of (99m)Tc-pertechnetate hand perfusion scintigraphy in patients with Raynaud's phenomenon (RP). The study population consisted of 18 patients with primary RP, 25 patients with secondary RP within systemic sclerosis (SSc), and ten healthy individuals. Gamma camera dynamic first-pass study during the first 60 s and a static scintigraphy after 5 min were recorded following a bolus injection of (99m)Tc-pertechnetate via a cubital vein. Regions of interest were drawn on the summed images around the fingers and the palmar region...
October 25, 2016: Rheumatology International
Saowalak Kalapanulak, Treenut Saithong, Chinae Thammarongtham
To understand how biological processes work, it is necessary to explore the systematic regulation governing the behaviour of the processes. Not only driving the normal behavior of organisms, the systematic regulation evidently underlies the temporal responses to surrounding environments (dynamics) and long-term phenotypic adaptation (evolution). The systematic regulation is, in effect, formulated from the regulatory components which collaboratively work together as a network. In the drive to decipher such a code of lives, a spectrum of technologies has continuously been developed in the post-genomic era...
October 26, 2016: Advances in Biochemical Engineering/biotechnology
Martina Zangheri, Fabio Di Nardo, Mara Mirasoli, Laura Anfossi, Augusto Nascetti, Domenico Caputo, Giampiero De Cesare, Massimo Guardigli, Claudio Baggiani, Aldo Roda
A novel and disposable cartridge for chemiluminescent (CL)-lateral flow immunoassay (LFIA) with integrated amorphous silicon (a-Si:H) photosensors array was developed and applied to quantitatively detect human serum albumin (HSA) in urine samples. The presented analytical method is based on an indirect competitive immunoassay using horseradish peroxidase (HRP) as a tracer, which is detected by adding the luminol/enhancer/hydrogen peroxide CL cocktail. The system comprises an array of a-Si:H photosensors deposited on a glass substrate, on which a PDMS cartridge that houses the LFIA strip and the reagents necessary for the CL immunoassay was optically coupled to obtain an integrated analytical device controlled by a portable read-out electronics...
October 25, 2016: Analytical and Bioanalytical Chemistry
Fabio D Steffen, Roland K O Sigel, Richard Börner
Carbocyanine dyes have a long-standing tradition in fluorescence imaging and spectroscopy, due to their photostability and large spectral separation between individual dye species. Herein, we explore the versatility of cyanine dyes to probe the dynamics of nucleic acids and we report on the interrelation of fluorophores, RNA, and metal ions, namely K(+) and Mg(2+). Photophysical parameters including the fluorescence lifetime, quantum yield and dynamic anisotropy are monitored as a function of the nucleic acid composition, conformation, and metal ion abundance...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
L Guariguata, C Guell, T A Samuels, E A J A Rouwette, J Woodcock, I R Hambleton, N Unwin
BACKGROUND: Diabetes is highly prevalent in the Caribbean, associated with a high morbidity and mortality and is a recognised threat to economic and social development. Heads of Government in the Caribbean Community came together in 2007 and declared their commitment to reducing the burden of non-communicable diseases (NCDs), including diabetes, by calling for a multi-sectoral, systemic response. To facilitate the development of effective policies, policymakers are being engaged in the development and use of a system dynamics (SD) model of diabetes for Caribbean countries...
October 26, 2016: Health Research Policy and Systems
Mohammad A Kaisar, Ravi K Sajja, Shikha Prasad, Vinay V Abhyankar, Taylor Liles, Luca Cucullo
The blood-brain barrier (BBB) is a dynamic biological interface which actively controls the passage of substances between the blood and the central nervous system (CNS). From a biological and functional standpoint, the BBB plays a crucial role in maintaining brain homeostasis inasmuch that deterioration of BBB functions are prodromal to many CNS disorders. Conversely, the BBB hinders the delivery of drugs targeting the brain to treat a variety of neurological diseases. Area covered: This article reviews recent technological improvements and innovation in the field of BBB modeling including static and dynamic cell-based platforms, microfluidic systems and the use of stem cells and 3D printing technologies...
October 26, 2016: Expert Opinion on Drug Discovery
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