4,947 research outputs found
Fabrication of Microfiber Patterns with Ivy Shoot-Like Geometries Using Improved Electrospinning
Fibers and fibrous structures are used extensively in various fields due to their many advantages. Microfibers, as well as nanofibers, are considered to be some of the most valuable forms of advanced materials. Accordingly, various methods for fabricating microfibers have been developed. Electrospinning is a useful fabrication method for continuous polymeric nano- and microfibers with attractive merits. However, this technique has limitations in its ability to control the geometry of fibrous structures. Herein, advanced electrospinning with direct-writing functionality was used to fabricate microfiber patterns with ivy shoot-like geometries after experimentally investigating the effects of the process conditions on the fiber formation. The surface properties of the fibers were also modified by introducing nanoscale pores through the use of higher levels of humidity during the fabrication process.ope
Regular Schur labeled skew shape posets and their 0-Hecke modules
Assuming Stanley's -partition conjecture holds, the regular Schur labeled
skew shape posets with underlying set are precisely the
posets such that the -partition generating function is symmetric and the
set of linear extensions of , denoted , is a left weak Bruhat
interval in the symmetric group . We describe the permutations
in in terms of reading words of standard Young tableaux when
is a regular Schur labeled skew shape poset, and classify 's up to
descent-preserving isomorphism as ranges over regular Schur labeled skew
shape posets. The results obtained are then applied to classify the -Hecke
modules associated with regular Schur labeled skew shape posets
up to isomorphism. Then we characterize regular Schur labeled skew shape
posets as the posets whose linear extensions form a dual plactic-closed subset
of . Using this characterization, we construct distinguished
filtrations of with respect to the Schur basis when is a
regular Schur labeled skew shape poset. Further issues concerned with the
classification and decomposition of the -Hecke modules are
also discussed.Comment: 44 page
Real-Time Monitoring of Nitric Oxide Dynamics in the Myocardium: Biomedical Application of Nitric Oxide Sensor
Nitric oxide (NO) is an important physiological mediator that regulates a wide range of cellular processes in many tissues. Therefore, the accurate and reliable measurement of physiological NO concentration is essential to the understanding of NO signaling and its biological role. Most methods used for NO detection are indirect including spectroscopic approaches such as the Griess assay for nitrite and detection of methemoglobin after NO reaction with oxyhemoglobin. These methods cannot accurately reflect the changes in NO concentration in vivo and in real time. Therefore, direct methods are necessary for investigating biological process and diseases related to NO in biological conditions. There is a growing interest in the development of electrochemically based sensors for direct, in vivo, and real-time monitoring of NO. Electrochemical methods offer simplicity, good sensitivity, high selectivity, fast response times, and long-term calibration stability compared to other techniques including electron paramagnetic resonance, chemiluminescence, and fluorescence. In this article, we present real-time NO dynamics in the myocardium during myocardial ischemia-reperfusion (IR) utilizing electrochemical NO microsensor. And applications of electrochemical NO sensor for the evaluation of cardioprotective effects of therapeutic treatments such as drug administration and ischemic preconditioning are reviewed
Structural behavior of concrete filled carbon fiber reinforced polymer sheet tube column
In order to examine both static and dynamic behaviors of Concrete Filled Carbon Fiber Reinforced Polymer Sheet Tube (CFCST) columns, experimental tests have been performed. The main variables of this experimental program included the number and wrapping angles of CFRP sheets. Stress versus strain relation of CFCST specimens was investigated by uni-axial tests. And, six full-scaled CFCST columns subjected to quasi-static lateral loading, as well as constant axial compression, were tested. Finally, an analytical procedure to predict the response of CFCST columns subjected to both axial and lateral loadings has been suggested in conjunction with the findings from the experimental tests
Preparative Synthesis of dTDP-L-Rhamnose Through Combined Enzymatic Pathways
dTDP-L-rhamnose, an important precursor of O-antigen, was prepared on a large scale from dTMP by executing an one-pot reaction in which six enzymes are involved. Two enzymes, dTDP-4-keto-6-deoxy-D-glucose 3,5-epimerase and dTDP-4-keto-rhamnose reductase, responsible for the conversion of dTDP-4-keto-6-deoxy- D-glucose to dTDP-L-rhamnose, were isolated from their putative sequences in the genome of Mesorhizobium loti, functionally expressed in Escherichia coli, and their enzymatic activities were identified. The two enzymes were combined with an enzymatic process for dTDP-4- keto-6-deoxy-D-glucose involving TMP kinase, acetate kinase, dTDP-glucose synthase, and dTDP-glucose 4,6- dehydratase, which allowed us to achieve a preparative scale synthesis of dTDP-L-rhamnose using dTMP and glucose-1-phosphate as starting materials. About 82% yield of dTDP-L-rhamnose was obtained based on initial dTMP concentration at 20 mM dTMP, 1 mM ATP, 10 mM NADH, 60 mM acetyl phosphate, and 80 mM glucose-1- phosphate. From the reaction with 20 ml volume, approximately 180 mg of dTDP-L-rhamnose was obtained in an overall yield of 60% after two-step purification, that is, anion exchange chromatography and gel filtration for desalting. The purified product was identifiedbyHPLC, ESI-MS,andNMR,showingabout95%purity
Characterization of GDP-mannose Pyrophosphorylase from Escherichia Coli O157:H7 EDL933 and Its Broad Substrate Specificity
GDP-mannose pyrophosphorylase gene (ManC) of Escherichia coli (E. coli) O157 was cloned and expressed as a highly soluble protein in E. coli BL21 (DE3). The enzyme was subsequently purified using hydrophobic and ion exchange chromatographies. ManC showed very broad substrate specificities for four nucleotides and various hexose-1-phosphates, yielding ADP-mannose, CDP-mannose, UDP-mannose, GDP-mannose, GDP-glucose and GDP-2-deoxy-glucose
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