2,120 research outputs found
Cloning, purification and characterization of the 6-phospho-3-hexulose isomerase YckF from Bacillus subtilis
The enzyme 6-phospho-3-hexulose isomerase (YckF) from Bacillus subtilis has been prepared and crystallized in a form suitable for X-ray crystallographic analysis. Crystals were grown by the hanging-drop method at 291 K using polyethylene glycol 2000 monomethylether as precipitant. They diffract beyond 1.7 A using an in-house Cu Kalpha source and belong to either space group P6(5)22 or P6(1)22, with unit-cell parameters a = b = 72.4, c = 241.2 A, and have two molecules of YckF in the asymmetric unit
Proactive inventory policy intervention to mitigate risk within cooperative supply chains
This exploratory paper will investigate the concept of supply chain risk management involving supplier monitoring within a cooperative supply chain. Inventory levels and stockouts are the key metrics. Key to this concept is the assumptions that (1) out-of-control supplier situations are causal triggers for downstream supply chain disruptions, (2) these triggers can potentially be predicted using statistical process monitoring tools, and (3) carrying excess inventory only when needed is preferable as opposed to carrying excess inventory on a continual basis. Simulation experimentation will be used to explore several supplier monitoring strategies based on statistical runs tests, specifically "runs up and down" and/or "runs above and below" tests. The sensitivity of these tests in detecting non-random supplier behavior will be explored and their performance will be investigated relative to stock-outs and inventory levels. Finally, the effects of production capacity and yield rate will be examined. Results indicate out-of-control supplier signals can be detected beforehand and stock-outs can be significantly reduced by dynamically adjusting inventory levels. The largest benefit occurs when both runs tests are used together and when the supplier has sufficient production capacity to respond to downstream demand (i.e., safety stock) increases. When supplier capacity is limited, the highest benefit is achieved when yield rates are high and, thus, yield loss does not increase supplier production requirements beyond its available capacity
TCT-142 Clinical Characteristics and Outcomes of Patients Undergoing Transcatheter Aortic Valve Replacement With STS PROM of ≤3%
Background Transcatheter aortic valve replacement (TAVR) is the preferred treatment for most patients with aortic stenosis deemed at intermediate or higher risk for surgical aortic valve replacement (SAVR). Determination of the risk of SAVR is mainly based on the Society of Thoracic Surgeons (STS) risk calculator. However, federal regulations permit the heart team latitude to offer TAVR for patients with ≤3% predicted risk of mortality (PROM) whose perceived risk is not adequately accounted for by the STS risk model. Limited data is available on the clinical characteristics and outcomes of these patients Methods The study group involved 2,539 patients who underwent TAVR from 2013 to 2017 within 7 hospitals in 5 Western states in the Providence St. Joseph Health system. The local TAVR site staff completed surveys identifying the clinical factors driving the heart team\u27s decision to proceed with TAVR. Clinical data was also collected per the TVT registry requirements. Results We identified 332 TAVR patients with STS PROM ≤3% and 2,207 patients with STS PROM \u3e3%. The percentage of TAVR patients with an STS PROM increased over time from 5.1% in 2013 to 16.6% in 2017. The most common factors (≥1 possible) influencing the heart team\u27s decision to proceed with TAVR in the ≤3% STS PROM group were frailty (63%), hostile chest (23%), severe lung disease (14%), morbid obesity (10%), and liver disease (8%). The baseline characteristics and outcomes of both groups are listed in the Table. Conclusion The proportion of TAVR patients with STS PROM ≤3% tripled from 2013 to 2017. In comparison to those with STS PROM \u3e3%, they were younger and more often men. The most common reasons driving the decision to favor TAVR over SAVR were frailty, hostile chest, and severe lung disease. TAVR patients with STS PROM ≤3% had shorter hospital stays and were more likely to be alive at 1 year
Structural Insights from Molecular Dynamics Simulations of Tryptophan 7-Halogenase and Tryptophan 5-Halogenase
Many natural organic
compounds with pharmaceutical applications,
including antibiotics (chlortetracycline and vancomycin), antifungal
compounds (pyrrolnitrin), and chemotherapeutics (salinosporamide A
and rebeccamycin) are chlorinated. Halogenating enzymes like tryptophan
7-halogenase (PrnA) and tryptophan 5-halogenase (PyrH) perform regioselective
halogenation of tryptophan. In this study, the conformational dynamics
of two flavin-dependent tryptophan halogenasesî—¸PrnA and PyrHî—¸was
investigated through molecular dynamics simulations, which are in
agreement with the crystallographic and kinetic experimental studies
of both enzymes and provide further explanation of the experimental
data at an atomistic level of accuracy. They show that the binding
sites of the cofactor-flavin adenine dinucleotide and the substrate
do not come into close proximity during the simulations, thus supporting
an enzymatic mechanism without a direct contact between them. Two
catalytically important active site residues, glutamate (E346/E354)
and lysine (K79/K75) in PrnA and PyrH, respectively, were found to
play a key role in positioning the proposed chlorinating agent, hypochlorous
acid. The changes in the regioselectivity between PrnA and PyrH arise
as a consequence of differences in the orientation of substrate in
its binding site
Repeat coronary angioplasty: Correlates of a second restenosis
AbstractTo identify the correlates of a second restenosis after repeat percutaneous coronary angioplasty, the records of 384 patients with single vessel disease who underwent repeat angioplasty for restenosis complicating a first elective angioplasty were examined. A second restenosis occurred in 47 (31%) of 151 patients having angiographic follow-up. Univariate correlates of a second restenosis were an interval between the first and the second angioplasty <5 months (41 versus 20% of patients had restenosis, p < 0.01), male gender (35 versus 12%, p < 0.05), lesion length ≥15 mm before the second angioplasty (62 versus 28%, p < 0.05), diameter stenosis >90% before the second angioplasty (67 versus 29%, p < 0.05), final gradient >20 mm Hg after the second angioplasty (52 versus 28%, p < 0.05) and an additional site requiring dilation at the time of the second angioplasty (50 versus 29%, p = 0.10).Multivarlate predictors of a second restenosis were an interval of <5 months between the first and the second angioplasty (p = 0.001), male gender (p = 0.001), lesion length ≥15 mm before the second angioplasty (p = 0.001) and the need to have an additional site dilated at the time of the second angioplasty (p = 0.002). Patients at increased risk of restenosis after the second angioplasty can be identified and may serve as a useful population for intervention studies
Biocatalytic and Chemo-Enzymatic Synthesis of Quinolines and 2-Quinolones by Monoamine Oxidase (MAO-N) and Horseradish Peroxidase (HRP) Biocatalysts
The oxidative aromatization of aliphatic N-heterocycles is a fundamental organic transformation for the preparation of a diverse array of heteroaromatic compounds. Despite many attempts to improve the efficiency and practicality of this transformation, most synthetic methodologies still require toxic and expensive reagents as well as harsh conditions. Herein, we describe two enzymatic strategies for the oxidation of 1,2,3,4-tetrahydroquinolines (THQs) and N-cyclopropyl-N-alkylanilines into quinolines and 2-quinolones, respectively. Whole cells and purified monoamine oxidase (MAO-N) enzymes were used to effectively catalyze the biotransformation of THQs into the corresponding aromatic quinoline derivatives, while N-cyclopropyl-N-alkylanilines were converted into 2-quinolone compounds through a horseradish peroxidase (HRP)-catalyzed annulation/aromatization reaction followed by Fe-mediated oxidation
How does conformational flexibility influence key structural features involved in activation of anaplastic lymphoma kinase?
Anaplastic Lymphoma Kinase (ALK) plays a major role in developing tumor processes and therefore has emerged as a validated therapeutic target. Applying atomistic molecular dynamics simulations on the wild type enzyme and the nine most frequently occurring and clinically important activation mutants we revealed important conformational effects on key interactions responsible for the activation of the enzyme
Sterol 3β-glucosyltransferase biocatalysts with a range of selectivities, including selectivity for testosterone
The main objectives of this work were to characterise a range of purified recombinant sterol 3β-glucosyltransferases and show that rational sampling of the diversity that exists within sterol 3β-glucosyltransferase sequence space can result in a range of enzyme selectivities. In our study the catalytically active domain of the Saccharomyces cerevisiae 3β-glucosyltransferase was used to mine putative sterol 3β-glucosyltransferases from the databases. Selected diverse sequences were expressed in and purified from Escherichia coli and shown to have different selectivities for the 3β-hydroxysteroids ergosterol and cholesterol. Surprisingly, three enzymes were also selective for testosterone, a 17β-hydroxysteroid. This study therefore reports for the first time sterol 3β-glucosyltransferases with selectivity for both 3β- and 17β-hydroxysteroids and is also the first report of recombinant 3β-glucosyltransferases with selectivity for steroids with a hydroxyl group at positions other than C-3. These enzymes could therefore find utility in the pharmaceutical industry for the green synthesis of a range of glycosylated compounds of medicinal interest
1977: Abilene Christian College Bible Lectures - Full Text
Seeking The Lost
Being the Abilene Christian University Annual Bible Lectures 1977
Published by
ABILENE CHRISTIAN UNIVERSITY Book Store
ACU Station Abilene, Texas 7960
Search for Interstellar Water in the Translucent Molecular Cloud toward HD 154368
We report an upper limit of 9 x 10^{12} cm-2 on the column density of water
in the translucent cloud along the line of sight toward HD 154368. This result
is based upon a search for the C-X band of water near 1240 \AA carried out
using the Goddard High Resolution Spectrograph of the Hubble Space Telescope.
Our observational limit on the water abundance together with detailed chemical
models of translucent clouds and previous measurements of OH along the line of
sight constrain the branching ratio in the dissociative recombination of H_3O+
to form water. We find at the level that no more than 30% of
dissociative recombinations of H_3O+ can lead to H_2O. The observed spectrum
also yielded high-resolution observations of the Mg II doublet at 1239.9 \AA
and 1240.4 \AA, allowing the velocity structure of the dominant ionization
state of magnesium to be studied along the line of sight. The Mg II spectrum is
consistent with GHRS observations at lower spectral resolution that were
obtained previously but allow an additional velocity component to be
identified.Comment: Accepted by ApJ, uses aasp
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