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https://www.readbyqxmd.com/read/28433000/elastic-moduli-of-electrospun-mats-importance-of-fiber-curvature-and-specimen-dimensions
#1
Vijay Kumar, Amit Rawal
Success of tissue engineering relies on the architecture and properties of porous scaffolds. Electrospun nonwoven scaffolds in the form of mats are unique materials due to large surface area to volume ratio, high porosity, versatility in surface functionalities and excellent mechanical properties. Maneuvering the mechanical behavior of the electrospun mat is a major challenge both from theoretical and experimental perspectives. Herein, we report a two-dimensional (2D) analytical model of normalized elastic moduli of electrospun mats by formulating a relationship with the governing fiber and structural parameters...
April 12, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28432818/characterization-of-decellularized-ovine-small-intestine-submucosal-layer-as-extracellular-matrix-based-scaffold-for-tissue-engineering
#2
Morteza Rashtbar, Jamshid Hadjati, Jafar Ai, Issa Jahanzad, Mahmoud Azami, Sadegh Shirian, Somayeh Ebrahimi-Barough, Esmaeil Sadroddiny
Extracellular matrix-based scaffolds derived from mammalian tissues have been used in tissue engineering applications. Among all the tissues, decellularized small intestine submucosal layer (SIS) has been recently investigated for its exceptional characteristics and biocompatibilities. These investigations have been mainly focused on the decellularized porcine SIS; however, there has not been any report on ovine SIS (OSIS) layer. In this study, OSIS was decellularized and its physical, chemical, and morphological properties were evaluated...
April 22, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/28432333/metabolomic-and-proteomic-analysis-of-maize-embryonic-callus-induced-from-immature-embryo
#3
Fei Ge, Hongmei Hu, Xing Huang, Yanling Zhang, Yanli Wang, Zhaoling Li, Chaoying Zou, Huanwei Peng, Lujiang Li, Shibin Gao, Guangtang Pan, Yaou Shen
The low ratio of embryonic callus (EC) induction has inhibited the rapid development of maize genetic engineering. Still, little is known to explain the genotype-dependence of EC induction. Here, we performed a large-scale, quantitative analysis of the maize EC metabolome and proteome at three typical induction stages in two inbred lines with a range of EC induction capabilities. Comparison of the metabolomes and proteomes suggests that the differential molecular responses begin at an early stage of development and continue throughout the process of EC formation...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28432100/casein-kinase-i-isoform-hrr25-is-a-negative-regulator-of-haa1-in-the-weak-acid-stress-response-pathway-in-saccharomyces-cerevisiae
#4
Morgan E Collins, Joshua J Black, Zhengchang Liu
Haa1 is a transcription factor that adapts Saccharomyces cerevisiae cells to weak organic acid stresses by activating the expression of various genes. Many of these genes encode membrane proteins such as TPO2 and YRO2 How Haa1 is activated by weak acids is not clear. Here, we show that casein kinase I isoform Hrr25 is an important negative regulator of Haa1. Haa1 is known to be multiply phosphorylated. We found that mutations in HRR25 lead to reduced Haa1 phosphorylation and increased expression of Haa1-target genes, and that Hrr25 interacts with Haa1...
April 21, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28432097/diazotrophy-overcomes-the-deleterious-growth-phenotype-of-glne-deletion-in-azotobacter-vinelandii
#5
Florence Mus, Alex Tseng, Ray Dixon, John W Peters
Overcoming the inhibitory effects of excess environmental ammonium on nitrogenase synthesis or activity, or preventing ammonium assimilation, have both been considered as strategies to increase the amount of fixed nitrogen transferred from bacterial to plant partners in associative or symbiotic plant-diazotroph relationships. The GlnE adenylyltransferase/adenylyl-removing enzyme catalyzes reversible adenylylation of glutamine synthetase (GS), thereby affecting the post translational regulation of ammonium assimilation critical for appropriate coordination of carbon and nitrogen assimilation...
April 21, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28431498/migrant-workers-in-italy-an-analysis-of-injury-risk-taking-into-account-occupational-characteristics-and-job-tenure
#6
Massimiliano Giraudo, Antonella Bena, Giuseppe Costa
BACKGROUND: Migrants resident in Italy exceeded 5 million in 2015, representing 8.2% of the resident population. The study of the mechanisms that explain the differential health of migrant workers (as a whole and for specific nationalities) has been identified as a priority for research. The international literature has shown that migrant workers have a higher risk of total and fatal injury than natives, but some results are conflicting. The aim of this paper is to study the injury risk differentials between migrants, born in countries with strong migratory pressure (SMPC), and workers born in high income countries (HIC), taking into account individual and firm characteristics and job tenure...
April 22, 2017: BMC Public Health
https://www.readbyqxmd.com/read/28430676/a-biomimetic-alternative-to-synthetic-hydroxyapatite-boron-containing-bone-like-hydroxyapatite-precipitated-from-simulated-body-fluid
#7
Mert Calis, Tugrul Tolga Demirtas, Alper Vatansever, Gulseren Irmak, Ahmet Hamdi Sakarya, Pergin Atilla, Figen Ozgur, Menemse Gumusderelioglu
BACKGROUND: Biological hydroxyapatite (HA), has several mechanical and physical advantages over the commercially available synthetic apatite (CAP-HA). The aim of this in vivo study was to investigate the effect of osteoinductive "bone-like hydroxyapatite" obtained from simulated body fluid (SBF) combined with osteoinductive "boron" (B) on bone healing. MATERIALS: Bone like nanohydroxyapatite (SBF-HA) was precipitated from 10× simulated body fluid (10×SBF). Thirty Sprague-Dawley rats were randomly divided into 5 experimental groups (n = 6 each)...
April 20, 2017: Annals of Plastic Surgery
https://www.readbyqxmd.com/read/28430301/towards-a-bioengineered-kidney-recellularization-strategies-for-decellularized-native-kidney-scaffolds
#8
Michele Fedecostante, Oana G Onciu, Koen G C Westphal, Rosalinde Masereeuw
Patients with end-stage renal disease often undergo dialysis as a partial substitute for kidney function while waiting for their only treatment option: a kidney transplant. Several research directions emerged for alternatives in support of the ever-growing numbers of patients. Recent years brought big steps forward in the field, with researchers questioning and improving the current dialysis devices as well as moving towards the design of a bioengineered kidney. Whole-organ engineering is also being explored as a possibility, making use of animal or human kidney scaffolds for engineering a transplantable organ...
April 20, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28429713/gating-of-tonb-dependent-transporters-by-substrate-specific-forced-remodelling
#9
Samuel J Hickman, Rachael E M Cooper, Luca Bellucci, Emanuele Paci, David J Brockwell
Membrane proteins play vital roles in inside-out and outside-in signal transduction by responding to inputs that include mechanical stimuli. Mechanical gating may be mediated by the membrane or by protein(s) but evidence for the latter is scarce. Here we use force spectroscopy, protein engineering and bacterial growth assays to investigate the effects of force on complexes formed between TonB and TonB-dependent transporters (TBDT) from Gram-negative bacteria. We confirm the feasibility of protein-only mediated mechanical gating by demonstrating that the interaction between TonB and BtuB (a TBDT) is sufficiently strong under force to create a channel through the TBDT...
April 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28429711/single-photon-test-of-hyper-complex-quantum-theories-using-a-metamaterial
#10
Lorenzo M Procopio, Lee A Rozema, Zi Jing Wong, Deny R Hamel, Kevin O'Brien, Xiang Zhang, Borivoje Dakić, Philip Walther
In standard quantum mechanics, complex numbers are used to describe the wavefunction. Although this has so far proven sufficient to predict experimental results, there is no theoretical reason to choose them over real numbers or generalizations of complex numbers, that is, hyper-complex numbers. Experiments performed to date have proven that real numbers are insufficient, but the need for hyper-complex numbers remains an open question. Here we experimentally probe hyper-complex quantum theories, studying one of their deviations from complex quantum theory: the non-commutativity of phases...
April 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28429326/wax-ester-fermentation-and-its-application-for-biofuel-production
#11
Hiroshi Inui, Takahiro Ishikawa, Masahiro Tamoi
In Euglena cells under anaerobic conditions, paramylon, the storage polysaccharide, is promptly degraded and converted to wax esters. The wax esters synthesized are composed of saturated fatty acids and alcohols with chain lengths of 10-18, and the major constituents are myristic acid and myristyl alcohol. Since the anaerobic cells gain ATP through the conversion of paramylon to wax esters, the phenomenon is named "wax ester fermentation". The wax ester fermentation is quite unique in that the end products, i...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28429319/biochemistry-and-physiology-of-heavy-metal-resistance-and-accumulation-in-euglena
#12
Rafael Moreno-Sánchez, Sara Rodríguez-Enríquez, Ricardo Jasso-Chávez, Emma Saavedra, Jorge D García-García
Free-living microorganisms may become suitable models for removal of heavy metals from polluted water bodies, sediments, and soils by using and enhancing their metal accumulating abilities. The available research data indicate that protists of the genus Euglena are a highly promising group of microorganisms to be used in bio-remediation of heavy metal-polluted aerobic and anaerobic acidic aquatic environments. This chapter analyzes the variety of biochemical mechanisms evolved in E. gracilis to resist, accumulate and remove heavy metals from the environment, being the most relevant those involving (1) adsorption to the external cell pellicle; (2) intracellular binding by glutathione and glutathione polymers, and their further compartmentalization as heavy metal-complexes into chloroplasts and mitochondria; (3) polyphosphate biosynthesis; and (4) secretion of organic acids...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28428821/genome-wide-search-for-candidate-genes-for-yeast-robustness-improvement-against-formic-acid-reveals-novel-susceptibility-trk1-and-positive-regulators-and-resistance-haa1-regulon-determinants
#13
Sílvia F Henriques, Nuno P Mira, Isabel Sá-Correia
BACKGROUND: Formic acid is an inhibitory compound present in lignocellulosic hydrolysates. Understanding the complex molecular mechanisms underlying Saccharomyces cerevisiae tolerance to this weak acid at the system level is instrumental to guide synthetic pathway engineering for robustness improvement of industrial strains envisaging their use in lignocellulosic biorefineries. RESULTS: This study was performed to identify, at a genome-wide scale, genes whose expression confers protection or susceptibility to formic acid, based on the screening of a haploid deletion mutant collection to search for these phenotypes in the presence of 60, 70 and 80 mM of this acid, at pH 4...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28428782/a-recombinant-potato-virus-y-infectious-clone-tagged-with-the-rosea1-visual-marker-pvy-ros1-facilitates-the-analysis-of-viral-infectivity-and-allows-the-production-of-large-amounts-of-anthocyanins-in-plants
#14
Teresa Cordero, Mohamed A Mohamed, Juan-José López-Moya, José-Antonio Daròs
Potato virus Y (PVY) is a major threat to the cultivation of potato and other solanaceous plants. By inserting a cDNA coding for the Antirrhinum majus Rosea1 transcription factor into a PVY infectious clone, we created a biotechnological tool (PVY-Ros1) that allows infection by this relevant plant virus to be tracked by the naked eye with no need for complex instrumentation. Rosea1 is an MYB-type transcription factor whose expression activates the biosynthesis of anthocyanin pigments in a dose-specific and cell-autonomous manner...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28428541/tissue-engineered-cornea-constructed-with-compressed-collagen-and-laser-perforated-electrospun-mat
#15
Bin Kong, Wei Sun, Guoshi Chen, Song Tang, Ming Li, Zengwu Shao, Shengli Mi
While Plastic Compressed (PC) collagen technique is often used to fabricate bioengineered constructs, PC collagen gels are too weak to be sutured or conveniently handled for clinical applications. To overcome this limitation, electrospun poly (lactic-co-glycolide) (PLGA) mats, which have excellent biocompatibility and mechanical properties, were combined with PC collagen to fabricate sandwich-like hybrid constructs. By laser-perforating holes with different sizes and spacings in the electrospun mats to regulate the mechanical properties and light transmittance of the hybrid constructs, we produced hybrid constructs with properties very suitable to apply in corneal tissue engineering...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28427825/molecular-mechanisms-of-the-yeast-adaptive-response-and-tolerance-to-stresses-encountered-during-ethanol-fermentation
#16
REVIEW
Choowong Auesukaree
During ethanol fermentation, yeast cells encounter various stresses including sugar substrates-induced high osmolarity, increased ethanol concentration, oxygen metabolism-derived reactive oxygen species (ROS), and elevated temperature. To cope with these fermentation-associated stresses, appropriate adaptive responses are required to prevent stress-induced cellular dysfunctions and to acquire stress tolerances. This review will focus on the cellular effects of these stresses, molecular basis of the adaptive response to each stress, and the cellular mechanisms contributing to stress tolerance...
April 17, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28427634/enhanced-porosity-and-permeability-of-three-dimensional-alginate-scaffolds-via-acoustic-microstreaming-induced-by-low-intensity-pulsed-ultrasound
#17
Gepu Guo, Yong Ma, Yang Guo, Chunbing Zhang, Xiasheng Guo, Juan Tu, Alfred C H Yu, Junru Wu, Dong Zhang
The shear stress resulting from the microstreaming induced by low-intensity pulsed ultrasound (LIPUS) has been often used to improve the permeability of cell membrane or porous engineering scaffolds. In the present study, three-dimensional (3-D) scaffold culture systems were constituted to simulate the in vivo microenvironment, providing benefits for cell growth. In order to investigate the mechanism underlying the enhanced porosity and permeability of the 3-D alginate scaffolds by using LIPUS with varied acoustic intensities, two quantitative imaging techniques (i...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427621/engineering-design-and-prototype-development-of-a-full-scale-ultrasound-system-for-virgin-olive-oil-by-means-of-numerical-and-experimental-analysis
#18
Maria Lisa Clodoveo, Vito Moramarco, Antonello Paduano, Raffaele Sacchi, Tiziana Di Palmo, Pasquale Crupi, Filomena Corbo, Vito Pesce, Elia Distaso, Paolo Tamburrano, Riccardo Amirante
The aim of the virgin olive oil extraction process is mainly to obtain the best quality oil from fruits, by only applying mechanical actions while guaranteeing the highest overall efficiency. Currently, the mechanical methods used to extract virgin oils from olives are basically of two types: the discontinuous system (obsolete) and the continuous one. Anyway the system defined as "continuous" is composed of several steps which are not all completely continuous, due to the presence of the malaxer, a device that works in batch...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427327/analysis-of-transcriptome-data-reveals-multifactor-constraint-on-codon-usage-in-taenia-multiceps
#19
Xing Huang, Jing Xu, Lin Chen, Yu Wang, Xiaobin Gu, Xuerong Peng, Guangyou Yang
BACKGROUND: Codon usage bias (CUB) is an important evolutionary feature in genomes that has been widely observed in many organisms. However, the synonymous codon usage pattern in the genome of T. multiceps remains to be clarified. In this study, we analyzed the codon usage of T. multiceps based on the transcriptome data to reveal the constraint factors and to gain an improved understanding of the mechanisms that shape synonymous CUB. RESULTS: Analysis of a total of 8,620 annotated mRNA sequences from T...
April 20, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28427272/biological-technologies-for-the-remediation-of-co-contaminated-soil
#20
Shujing Ye, Guangming Zeng, Haipeng Wu, Chang Zhang, Juan Dai, Jie Liang, Jiangfang Yu, Xiaoya Ren, Huan Yi, Min Cheng, Chen Zhang
Compound contamination in soil, caused by unreasonable waste disposal, has attracted increasing attention on a global scale, particularly since multiple heavy metals and/or organic pollutants are entering natural ecosystem through human activities, causing an enormous threat. The remediation of co-contaminated soil is more complicated and difficult than that of single contamination, due to the disparate remediation pathways utilized for different types of pollutants. Several modern remediation technologies have been developed for the treatment of co-contaminated soil...
April 21, 2017: Critical Reviews in Biotechnology
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