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https://www.readbyqxmd.com/read/27932963/distinct-neural-substrates-for-maintaining-locations-and-spatial-relations-in-working-memory
#1
Kara J Blacker, Susan M Courtney
Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM): spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27932679/tendon-collagen-synthesis-declines-with-immobilization-in-elderly-humans-no-effect-of-anti-inflammatory-medication
#2
Kasper Dideriksen, Anders Ploug Boesen, Søren Reitelseder, Christian Couppe, Rene Brüggebusch Svensson, Peter Schjerling, S Peter Magnusson, Lars Holm, Michael Kjaer
BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAID) are used as pain killers during periods of unloading caused by traumatic occurrences or diseases. However, it is unknown how the tendon protein turnover and mechanical properties responds to unloading and subsequent loading in elderly humans, and especially whether NSAIDs affect tendon adaptation during such periods. Thus, we studied the influence of NSAID upon the human patellar tendon protein synthesis and mechanical properties during immobilization and subsequent rehabilitating resistance training...
December 8, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27932447/unloading-of-homologous-recombination-factors-is-required-for-restoring-double-stranded-dna-at-damage-repair-loci
#3
Yulia Vasianovich, Veronika Altmannova, Oleksii Kotenko, Matthew D Newton, Lumir Krejci, Svetlana Makovets
Cells use homology-dependent DNA repair to mend chromosome breaks and restore broken replication forks, thereby ensuring genome stability and cell survival. DNA break repair via homology-based mechanisms involves nuclease-dependent DNA end resection, which generates long tracts of single-stranded DNA required for checkpoint activation and loading of homologous recombination proteins Rad52/51/55/57. While recruitment of the homologous recombination machinery is well characterized, it is not known how its presence at repair loci is coordinated with downstream re-synthesis of resected DNA We show that Rad51 inhibits recruitment of proliferating cell nuclear antigen (PCNA), the platform for assembly of the DNA replication machinery, and that unloading of Rad51 by Srs2 helicase is required for efficient PCNA loading and restoration of resected DNA As a result, srs2Δ mutants are deficient in DNA repair correlating with extensive DNA processing, but this defect in srs2Δ mutants can be suppressed by inactivation of the resection nuclease Exo1...
December 8, 2016: EMBO Journal
https://www.readbyqxmd.com/read/27932408/early-responses-of-human-periodontal-ligament-fibroblasts-to-cyclic-and-static-mechanical-stretching
#4
Adamantia Papadopoulou, Anna Iliadi, Theodore Eliades, Dimitris Kletsas
OBJECTIVE: To compare the mechanotransduction caused by cyclic and static mechanical strains in human periodontal ligament fibroblasts (hPDLFs) cultured under identical conditions. MATERIALS AND METHODS: hPDLFs, originating from the same donors, were exposed either to cyclic or to static tensile strain using specially designed devices and under identical culture conditions. Activation of all members of mitogen-activated protein kinases (MAPKs) was monitored by western immunoblot analysis...
December 8, 2016: European Journal of Orthodontics
https://www.readbyqxmd.com/read/27932212/atmospheric-deposition-of-particles-at-a-sensitive-alpine-lake-size-segregated-daily-and-annual-fluxes-from-passive-sampling-techniques
#5
Anna Y-C Tai, L-W Antony Chen, Xiaoliang Wang, Judith C Chow, John G Watson
Lake Tahoe, a North American alpine lake long appreciated for its clear water and geographic setting, has experienced a trend of declining water clarity due to increasing nutrient and particle inputs. Contributions from atmospheric deposition of particulate matter (PM) could be important, yet they are inadequately quantified. This study established a yearlong deposition monitoring network in the northern Lake Tahoe Basin. Dry deposition was quantified on surrogate surfaces while wet deposition was based on particles suspended in precipitation at 24-hour resolution...
December 5, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27931851/spanish-broom-spartium-junceum-l-fibers-impregnated-with-vancomycin-loaded-chitosan-nanoparticles-as-new-antibacterial-wound-dressing-preparation-characterization-and-antibacterial-activity
#6
T Cerchiara, A Abruzzo, R A Ñahui Palomino, B Vitali, R De Rose, G Chidichimo, L Ceseracciu, A Athanassiou, B Saladini, F Dalena, F Bigucci, B Luppi
In this work, we propose as new wound dressing, the Spanish Broom fibers impregnated with vancomycin (VM) loaded chitosan nanoparticles. Spanish Broom fibers were extracted by patented method DiCoDe and the morphological, physical and mechanical properties were investigated. Chitosan nanoparticles were prepared by ionic gelation using different weight ratios between chitosan (CH) and tripolyphosphate (TPP). Nanoparticles were characterized in terms of size, zeta potential, yield, encapsulation efficiency, stability and drug release...
December 5, 2016: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/27930304/emergent-oscillations-assist-obstacle-negotiation-during-ant-cooperative-transport
#7
Aviram Gelblum, Itai Pinkoviezky, Ehud Fonio, Nir S Gov, Ofer Feinerman
Collective motion by animal groups is affected by internal interactions, external constraints, and the influx of information. A quantitative understanding of how these different factors give rise to different modes of collective motion is, at present, lacking. Here, we study how ants that cooperatively transport a large food item react to an obstacle blocking their path. Combining experiments with a statistical physics model of mechanically coupled active agents, we show that the constraint induces a deterministic collective oscillatory mode that facilitates obstacle circumvention...
December 5, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27929139/a-piezoelectric-micro-generator-worked-at-low-frequency-and-high-acceleration-based-on-pzt-and-phosphor-bronze-bonding
#8
Gang Tang, Bin Yang, Cheng Hou, Guimiao Li, Jingquan Liu, Xiang Chen, Chunsheng Yang
Recently, piezoelectric energy harvesters (PEHs) have been paid a lot of attention by many researchers to convert mechanical energy into electrical and low level vibration. Currently, most of PEHs worked under high frequency and low level vibration. In this paper, we propose a micro cantilever generator based on the bonding of bulk PZT wafer and phosphor bronze, which is fabricated by MEMS technology, such as mechanical chemical thinning and etching. The experimental results show that the open-circuit output voltage, output power and power density of this fabricated prototype are 35 V, 321 μW and 8664 μW cm(-3) at the resonant frequency of 100...
December 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27929104/microneedles-with-controlled-bubble-sizes-and-drug-distributions-for-efficient-transdermal-drug-delivery
#9
Qi Lei Wang, Dan Dan Zhu, Xu Bo Liu, Bo Zhi Chen, Xin Dong Guo
Drug loaded dissolving microneedles (DMNs) fabricated with water soluble polymers have received increasing attentions as a safe and efficient transdermal drug delivery system. Usually, to reach a high drug delivery efficiency, an ideal drug distribution is gathering more drugs in the tip or the top part of DMNs. In this work, we introduce an easy and new method to introduce a bubble with controlled size into the body of DMNs. The introduction of bubbles can prevent the drug diffusion into the whole body of the MNs...
December 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27928670/tensile-strength-and-failure-load-of-sutures-for-robotic-surgery
#10
Ahmad Abiri, Omeed Paydar, Anna Tao, Megan LaRocca, Kang Liu, Bradley Genovese, Robert Candler, Warren S Grundfest, Erik P Dutson
BACKGROUND: Robotic surgical platforms have seen increased use among minimally invasive gastrointestinal surgeons (von Fraunhofer et al. in J Biomed Mater Res 19(5):595-600, 1985. doi: 10.1002/jbm.820190511 ). However, these systems still suffer from lack of haptic feedback, which results in exertion of excessive force, often leading to suture failures (Barbash et al. in Ann Surg 259(1):1-6, 2014. doi: 10.1097/SLA.0b013e3182a5c8b8 ). This work catalogs tensile strength and failure load among commonly used sutures in an effort to prevent robotic surgical consoles from exceeding identified thresholds...
December 7, 2016: Surgical Endoscopy
https://www.readbyqxmd.com/read/27928595/-left-ventricular-unloading-in-cardiogenic-shock
#11
A Schäfer, J Bauersachs
Cardiogenic shock is an acute life-threatening condition, which results in impaired end-organ perfusion and oxygenation. Invasive ventilation and medicinal treatment with inotropes or vasopressors are necessary in most cases; however, they are also associated with reduced long-term prognosis. Frequently, medical treatment is not even sufficient to stabilize the patient; therefore, dedicated mechanical circulatory support devices that actively reduce the load on the left ventricle were developed to allow myocardial recovery or to gain time until definitive treatment...
December 7, 2016: Herz
https://www.readbyqxmd.com/read/27928513/suzuki-miyaura-cross-coupling-optimization-enabled-by-automated-feedback
#12
Brandon J Reizman, Yi-Ming Wang, Stephen L Buchwald, Klavs F Jensen
An automated, droplet-flow microfluidic system explores and optimizes Pd-catalyzed Suzuki-Miyaura cross-coupling reactions. A smart optimal DoE-based algorithm is implemented to increase the turnover number and yield of the catalytic system considering both discrete variables-palladacycle and ligand-and continuous variables-temperature, time, and loading-simultaneously. The use of feedback allows for experiments to be run with catalysts and under conditions more likely to produce an optimum; consequently complex reaction optimizations are completed within 96 experiments...
December 1, 2016: Reaction Chemistry & Engineering
https://www.readbyqxmd.com/read/27928013/herpes-simplex-virus-1-ul41-protein-suppresses-the-ire1-xbp1-signal-pathway-of-the-unfolded-protein-response-via-its-rnase-activity
#13
Pengchao Zhang, Chenhe Su, Zhangtao Jiang, Chunfu Zheng
: During viral infection, accumulation of viral proteins can cause stress in the endoplasmic reticulum (ER) and trigger the unfolded protein response (UPR) to restore the ER homeostasis. Inositol-requiring enzyme 1 (IRE1)-dependent pathway is the most conserved one of the three UPR signal pathways. Upon activation, IRE1 splices out an intron from the unspliced inactive form X-box binding protein 1 (XBP1(u)) mRNA and produces a transcriptionally potent spliced form (XBP1(s)). Previous studies have reported that the IRE1/XBP1 pathway is inhibited upon herpes simplex virus 1 (HSV-1) infection, however, the underlying molecular mechanism is still illusive...
December 7, 2016: Journal of Virology
https://www.readbyqxmd.com/read/27928004/the-effect-of-hiv-1-env-on-serinc5-antagonism
#14
Saina Beitari, Shilei Ding, Qinghua Pan, Andrés Finzi, Chen Liang
: SERINC5 is able to restrict HIV-1 infection by drastically impairing the infectivity of viral particles. Current studies have shown that HIV-1 Nef protein counters SERINC5 through down regulating SERINC5 from the cell surface and preventing virion incorporation of SERINC5. In addition, the Env proteins of some HIV-1 strains can also overcome SERINC5 inhibition. However, it is unclear how HIV-1 Env does so and why HIV-1 has two mechanisms to resist SERINC5 inhibition. Results of this study show that neither Env nor Nef prevents high-level ectopic SERINC5 from incorporation into HIV-1 particles, except that Env, but not Nef, is able to resist the inhibition of virion-associated SERINC5...
December 7, 2016: Journal of Virology
https://www.readbyqxmd.com/read/27926851/energy-output-from-a-single-outer-hair-cell
#15
Kuni H Iwasa
Electromotility of outer hair cells (OHCs) has been extensively studied with in vitro experiments because of its physiological significance to the cochlear amplifier, which provides the exquisite sensitivity and frequency selectivity of the mammalian ear. However, these studies have been performed largely under load-free conditions or with static load, while these cells function in vivo in a dynamic environment, receiving electrical energy to enhance mechanical oscillation in the inner ear. This gap leaves uncertainties in addressing a key issue, how much mechanical energy an OHC provides...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27925440/enhancing-bioactive-properties-of-silk-fibroin-with-diatom-particles-for-bone-tissue-engineering-applications
#16
Thi Duy Hanh Le, Volha Liaudanskaya, Walter Bonani, Claudio Migliaresi, Antonella Motta
Many studies have highlighted the role of silicon in human bone formation and maintenance. Silicon, in fact, is considered to nucleate the precipitation of hydroxyapatite and to reduce the bone resorption. For this reason, we have combined silk fibroin with silicon releasing diatom particles, as potential material for bone tissue engineering applications. Sponges of fibroin loaded with different amounts and sizes of diatom particles were prepared by solvent casting-particulate leaching method, and their morphology, porosity and mechanical properties were evaluated...
December 7, 2016: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/27925236/stresses-and-strains-analysis-using-different-palatal-expander-appliances-in-upper-jaw-and-midpalatal-suture
#17
Larissa Carvalho Trojan, Libardo Andrés González-Torres, Ana Claudia Moreira Melo, Estevam Barbosa de Las Casas
Rapid maxillary expansion (RME) is the technique of increasing the transverse dimension of the upper jaw using lateral forces applied by palatal expander. Usually, this palatal appliance is anchored on posterior teeth. The purposes of this computer simulation study were to analyze the stress and strain distribution generated in the maxilla, mainly in midpalatal suture (MPS), during RME by tooth-borne and bone-borne expanders and to study the correlation between mechanical strain and Wolff's Law. The analysis was performed with finite element models developed based on Cone Beam computed tomography (CT)...
December 7, 2016: Artificial Organs
https://www.readbyqxmd.com/read/27924355/avp-dynamically-increases-paracellular-na-permeability-and-transcellular-nacl-transport-in-the-medullary-thick-ascending-limb-of-henle-s-loop
#18
REVIEW
Nina Himmerkus, Allein Plain, Rita D Marques, Svenja R Sonntag, Alexander Paliege, Jens Leipziger, Markus Bleich
The medullary thick ascending limb of Henle's loop (mTAL) is crucial for urine-concentrating ability of the kidney. It is water tight and able to dilute the luminal fluid by active transcellular NaCl transport, fueling the counter current mechanism by increasing interstitial osmolality. While chloride is exclusively transported transcellularly, approx. 50% of sodium transport occurs via the paracellular route, driven by the lumen-positive transepithelial potential. Antidiuretic hormone (AVP) is known to increase active NaCl transport to support collecting duct water reabsorption...
December 6, 2016: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/27923980/humanin-skeletal-muscle-protein-levels-increase-after-resistance-training-in-men-with-impaired-glucose-metabolism
#19
Eva-Karin Gidlund, Ferdinand von Walden, Mika Venojärvi, Ulf Risérus, Olli J Heinonen, Jessica Norrbom, Carl Johan Sundberg
Humanin (HN) is a mitochondrially encoded and secreted peptide linked to glucose metabolism and tissue protecting mechanisms. Whether skeletal muscle HN gene or protein expression is influenced by exercise remains unknown. In this intervention study we show, for the first time, that HN protein levels increase in human skeletal muscle following 12 weeks of resistance training in persons with prediabetes. Male subjects (n = 55) with impaired glucose regulation (IGR) were recruited and randomly assigned to resistance training, Nordic walking or a control group...
December 2016: Physiological Reports
https://www.readbyqxmd.com/read/27923658/temporal-regulation-of-gap-junctional-communication-between-tenocytes-subjected-to-static-tensile-strain-with-physiological-and-non-physiological-amplitudes
#20
Eijiro Maeda, Haicheng Pian, Toshiro Ohashi
The present study has been performed on temporal changes in gap junctional intercellular communication (GJIC) between tenocytes under static tensile strain with the magnitude of 0% (no strain), 4% (physiological magnitude) or 8% (overloading magnitude) during a 24-h culture period. Tenocytes were isolated from rabbit Achilles tendon and seeded on a stretchable microgroove substrate. GJIC was evaluated as intercellular diffusion coefficient of calcein (DGJ) using fluorescence loss in photobleaching (FLIP) protocol accompanied with a mathematical model of molecular diffusion both within the cell and between the cells...
December 3, 2016: Biochemical and Biophysical Research Communications
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