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David Hasler, Dominik Obrist
The flow field past a prosthetic aortic valve comprises many details that indicate whether the prosthesis is functioning well or not. It is, however, not yet fully understood how an optimal flow scenario would look, i.e. which subtleties of the fluid dynamics in place are essential regarding the durability and compatibility of a prosthetic valve. In this study, we measured and analyzed the 3D flow field in the vicinity of a bio-prosthetic heart valve in function of the aortic root size. The measurements were conducted within aortic root phantoms of different size, mounted in a custom-built hydraulic setup, which mimicked physiological flow conditions in the aorta...
2018: PloS One
Caleb J Bashor, James J Collins
Engineering synthetic gene regulatory circuits proceeds through iterative cycles of design, building, and testing. Initial circuit designs must rely on often-incomplete models of regulation established by fields of reductive inquiry-biochemistry and molecular and systems biology. As differences in designed and experimentally observed circuit behavior are inevitably encountered, investigated, and resolved, each turn of the engineering cycle can force a resynthesis in understanding of natural network function...
March 16, 2018: Annual Review of Biophysics
Masao Morita, Yuichi Kobayashi
The stereoselective synthesis of resolvin D4 (RvD4) was achieved using the Wittig reaction of the C1-C10 dienal with the known C11-C22 phosphonium salt. The (S,E)-enantiomer (S)-10, corresponding to the C1-C8 part, was synthesized in 95% ee by the asymmetric transfer hydrogenation reaction of the corresponding acetylenic ketone followed by Red-Al reduction. Sharpless epoxidation of this alcohol using Ti(O-i-Pr)4/L-(+)-DIPT as a catalyst produced anti epoxy alcohol with >99% ee as the sole product in 82% yield...
March 16, 2018: Journal of Organic Chemistry
Siwapon Srisonphan
Advanced surface engineering aims to produce surfaces with well-controlled wettabilities; however, precise control over water imbibition and liquid spreading on patterned surfaces remains a challenge. Nonthermal atmospheric plasma (NAP) treatment can dramatically change wettability; however, for coated biological objects, such as seeds, plasma interaction is not entirely understood. Herein, we employed atmospheric hybrid cold plasma (HCP) to elucidate how NAP fundamentally interacts with seed surfaces. We show that nonthermal atmospheric plasma can control water imbibition (WI) and liquid spreading on seeds...
March 16, 2018: ACS Applied Materials & Interfaces
Jejoong Yoo, Aleksei Aksimentiev
In contrast to ordinary polymers, the vast majority of biological macromolecules adopt highly ordered three-dimensional structures that define their functions. The key to folding of a biopolymer into a unique 3D structure or to an assembly of several biopolymers into a functional unit is a delicate balance between the attractive and repulsive forces that also makes such self-assembly reversible under physiological conditions. The all-atom molecular dynamics (MD) method has emerged as a powerful tool for studies of individual biomolecules and their functional assemblies, encompassing systems of ever increasing complexity...
March 16, 2018: Physical Chemistry Chemical Physics: PCCP
Sophie Meuret, Toon Coenen, Steffi Woo, Yong-Ho Ra, Zetian Mi, Albert Polman
Cathodoluminescence (CL) imaging spectroscopy provides two-dimensional optical excitation images of photonic nanostructures with deep-subwavelength spatial resolution. So far, CL imaging was unable to provide a direct measurement of the excitation and emission probabilities of photonic nanostructures in a spatially resolved manner. Here, we demonstrate that by mapping the cathodoluminescence autocorrelation function g(2) together with the CL spectral distribution the excitation and emission rates can be disentangled at every excitation position...
March 16, 2018: Nano Letters
Ayori Mitsutake, Hiroshi Takano
Molecular dynamics simulation is a powerful method for investigating the structural stability, dynamics, and function of biopolymers at the atomic level. In recent years, it has become possible to perform simulations on time scales of the order of milliseconds using special hardware. However, it is necessary to derive the important factors contributing to structural change or function from the complicated movements of biopolymers obtained from long simulations. Although some analysis methods for protein systems have been developed using increasing simulation times, many of these methods are static in nature (i...
March 15, 2018: Biophysical Reviews
Sarah Freitas Magalhães, Sofia Calvo-Rodriguez, Mário Marcos do Espírito Santo, Gerardo Arturo Sánchez Azofeifa
Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation...
March 15, 2018: International Journal of Biometeorology
Lokesh K Narnoliya, Rajender S Sangwan, Sudhir P Singh
Rose-scented geranium (Pelargonium sp.) is widely known as aromatic and medicinal herb, accumulating specialized metabolites of high economic importance, such as essential oils, ascorbic acid, and tartaric acid. Ascorbic acid and tartaric acid are multifunctional metabolites of human value to be used as vital antioxidants and flavor enhancing agents in food products. No information is available related to the structural and functional properties of the enzymes involved in ascorbic acid and tartaric acid biosynthesis in rose-scented geranium...
March 15, 2018: Molecular Biology Reports
Liting Jin, Ying Qu, Liliana J Gomez, Stacey Chung, Bingchen Han, Bowen Gao, Yong Yue, Yiping Gong, Xuefeng Liu, Farin Amersi, Catherine Dang, Armando E Giuliano, Xiaojiang Cui
Purpose: Conditional reprogramming methods allow for the inexhaustible in vitro proliferation of primary epithelial cells from human tissue specimens. This methodology has the potential to enhance the utility of primary cell culture as a model for mammary gland research. However, few studies have systematically characterized this method in generating in vitro normal human mammary epithelial cell models. Results: We show that cells derived from fresh normal breast tissues can be propagated and exhibit heterogeneous morphologic features...
February 20, 2018: Oncotarget
Guillermo de Anda-Jáuregui, Kai Guo, Brett A McGregor, Junguk Hur
The quintessential biological response to disease is inflammation. It is a driver and an important element in a wide range of pathological states. Pharmacological management of inflammation is therefore central in the clinical setting. Anti-inflammatory drugs modulate specific molecules involved in the inflammatory response; these drugs are traditionally classified as steroidal and non-steroidal drugs. However, the effects of these drugs are rarely limited to their canonical targets, affecting other molecules and altering biological functions with system-wide effects that can lead to the emergence of secondary therapeutic applications or adverse drug reactions (ADRs)...
2018: Frontiers in Physiology
Luqing Wei, Hong Chen, Guo-Rong Wu
The neurovisceral integration model has shown a key role of the amygdala in neural circuits underlying heart rate variability (HRV) modulation, and suggested that reciprocal connections from amygdala to brain regions centered on the central autonomic network (CAN) are associated with HRV. To provide neuroanatomical evidence for these theoretical perspectives, the current study used covariance analysis of MRI-based gray matter volume (GMV) to map structural covariance network of the amygdala, and then determined whether the interregional structural correlations related to individual differences in HRV...
2018: Frontiers in Human Neuroscience
Sini M Kinnunen, Marja Tölli, Mika J Välimäki, Erhe Gao, Zoltan Szabo, Jaana Rysä, Mónica P A Ferreira, Pauli Ohukainen, Raisa Serpi, Alexandra Correia, Ermei Mäkilä, Jarno Salonen, Jouni Hirvonen, Hélder A Santos, Heikki Ruskoaho
Transcription factors are fundamental regulators of gene transcription, and many diseases, such as heart diseases, are associated with deregulation of transcriptional networks. In the adult heart, zinc-finger transcription factor GATA4 is a critical regulator of cardiac repair and remodelling. Previous studies also suggest that NKX2-5 plays function role as a cofactor of GATA4. We have recently reported the identification of small molecules that either inhibit or enhance the GATA4-NKX2-5 transcriptional synergy...
March 15, 2018: Scientific Reports
Xiao-Ling Yang, Yolandi van der Merwe, Jeffrey Sims, Carlos Parra, Leon C Ho, Joel S Schuman, Gadi Wollstein, Kira L Lathrop, Kevin C Chan
Although elevated intraocular pressure (IOP) and age are major risk factors for glaucoma, their effects on glaucoma pathogenesis remain unclear. This study examined the onset and progression of glaucomatous changes to ocular anatomy and physiology, structural and physiological brain integrity, and visuomotor behavior in the DBA/2J mice via non-invasive tonometry, multi-parametric magnetic resonance imaging (MRI) and optokinetic assessments from 5 to 12 months of age. Using T2-weighted MRI, diffusion tensor MRI, and manganese-enhanced MRI, increasing IOP elevation at 9 and 12 months old coincided with anterior chamber deepening, altered fractional anisotropy and radial diffusivity of the optic nerve and optic tract, as well as reduced anterograde manganese transport along the visual pathway respectively in the DBA/2J mice...
March 15, 2018: Scientific Reports
Yanting Wang, Wenxian Lan, Zhenzhen Yan, Jing Gao, Xinlian Liu, Sheng Wang, Xiying Guo, Chunxi Wang, Hu Zhou, Jiuping Ding, Chunyang Cao
Large-conductance Ca2+ - and voltage-dependent K+ (BK) channels display diverse biological functions while their pore-forming α subunit is coded by a single Slo1 gene. The variety of BK channels is correlated with the effects of BKα coexpression with auxiliary β (β1-β4) subunits, as well as newly defined γ subunits. Charybdotoxin (ChTX) blocks BK channel through physically occluding the K+ -conduction pore. Human brain enriched β4 subunit (hβ4) alters the conductance-voltage curve, slows activation and deactivation time courses of BK channels...
March 15, 2018: Scientific Reports
Tiffany A Thibaudeau, Raymond T Anderson, David M Smith
Protein accumulation and aggregation with a concomitant loss of proteostasis often contribute to neurodegenerative diseases, and the ubiquitin-proteasome system plays a major role in protein degradation and proteostasis. Here, we show that three different proteins from Alzheimer's, Parkinson's, and Huntington's disease that misfold and oligomerize into a shared three-dimensional structure potently impair the proteasome. This study indicates that the shared conformation allows these oligomers to bind and inhibit the proteasome with low nanomolar affinity, impairing ubiquitin-dependent and ubiquitin-independent proteasome function in brain lysates...
March 15, 2018: Nature Communications
Michael D Oberst, Catherine Auge, Chad Morris, Stacy Kentner, Kathy Mulgrew, Kelly McGlinchey, James Hair, Shino Hanabuchi, Qun Du, Melissa Damschroder, Hui Feng, Steven Eck, Nicholas Buss, Lolke de Haan, Andrew J Pierce, Haesun Park, Andrew Sylwester, Michael K Axthelm, Louis Picker, Nicholas P Morris, Andrew Weinberg, Scott A Hammond
Ligation of OX40 (CD134, TNFRSF4) on activated T cells by its natural ligand (OX40L, CD252, TNFSF4) enhances cellular survival, proliferation, and effector functions such as cytokine release and cellular cytotoxicity. We engineered a recombinant human OX40L IgG4P Fc fusion protein termed MEDI6383 that assembles into a hexameric structure and exerts potent agonist activity following engagement of OX40. MEDI6383 displayed solution phase agonist activity that was enhanced when the fusion protein was clustered by Fc gamma receptors (FcγRs) on the surface of adjacent cells...
March 15, 2018: Molecular Cancer Therapeutics
Sean C Edington, Andrea Gonzalez, Thomas R Middendorf, D Brent Halling, Richard W Aldrich, Carlos R Baiz
The Ca2+ -sensing protein calmodulin (CaM) is a popular model of biological ion binding since it is both experimentally tractable and essential to survival in all eukaryotic cells. CaM modulates hundreds of target proteins and is sensitive to complex patterns of Ca2+ exposure, indicating that it functions as a sophisticated dynamic transducer rather than a simple on/off switch. Many details of this transduction function are not well understood. Fourier transform infrared (FTIR) spectroscopy, ultrafast 2D infrared (2D IR) spectroscopy, and electronic structure calculations were used to probe interactions between bound metal ions (Ca2+ and several trivalent lanthanide ions) and the carboxylate groups in CaM's EF-hand ion-coordinating sites...
March 15, 2018: Proceedings of the National Academy of Sciences of the United States of America
Daniel E O'Brien, Douglas M Shaw, Hyekyung P Cho, Alan J Cross, Steven S Wesolowski, Andrew S Felts, Jonas Bergare, Charles S Elmore, Craig W Lindsley, Colleen M Niswender, P Jeffrey Conn
Allosteric modulation of metabotropic glutamate receptor 2 (mGlu2) has demonstrated efficacy in preclinical rodent models of several brain disorders, leading to industry and academic drug discovery efforts. Although the pharmacology and binding sites of some mGlu2 allosteric modulators have been characterized previously, questions remain about the nature of the allosteric mechanism of cooperativity with glutamate and whether structurally diverse allosteric modulators bind in an identical manner to specific allosteric sites...
March 15, 2018: Molecular Pharmacology
Doodipala Samba Reddy
Neurosteroids like allopregnanolone (AP) are positive allosteric modulators of synaptic and extrasynaptic GABA-A receptors. AP and related neurosteroids exhibit a greater potency for δ-containing extrasynaptic receptors. The δGABA-A receptors, which are expressed extrasynaptically in the dentate gyrus and other regions, contribute to tonic inhibition, promoting network shunting as well as reducing seizure susceptibility. Levels of endogenous neurosteroids fluctuate with ovarian cycle. Natural and synthetic neurosteroids maximally potentiate tonic inhibition in the hippocampus and provide robust protection against a variety of limbic seizures and status epilepticus...
2018: Vitamins and Hormones
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