2,282 research outputs found
Alloy Design to Prevent Intergranular Corrosion of Low-Cr Ferritic Stainless Steel with Weak Carbide Formers
Effect of weak carbide formers, Mo, Mn and Si, on intergranular corrosion (IGC) of low-Cr ferritic stainless steel is analyzed after IGC test using TEM and three dimensional atom probe. The co-addition ofMo, Mn and Si to low-Cr ferritic stainless steel effectively prevents IGC by forming along grain boundaries CMn4MoSi intermetallic compounds, which act not only as carbon trap sites but also as diffusion barrier against solute Cr diffusion toward grain boundaries. The low solubility of Cr in the CMn4MoSi intermetallic compound results in replenishing Cr in the Cr-depleted area. (C) The Author(s) 2015. Published by ECS. All rights reserved.114Ysciescopu
Functional features of an ssi signal of plasmid pGKV21 in Escherichia coli
A single-strand initiation (ssi) signal was detected on the Lactococcus lactis plasmid pGKV21 containing the replicon of pWV01 by its ability to complement the poor growth of an M13 phage derivative (M13??lac182) lacking the complementary-strand origin in Escherichia coli. This ssi signal was situated at the 229-nucleotide (nt) DdeI-DraI fragment and located within the 109 nt upstream of the nick site of the putative plus origin. SSI activity is orientation specific with respect to the direction of replication. We constructed an ssi signal-deleted plasmid and then examined the effects of the ssi signal on the conversion of the single-stranded replication intermediate to double-stranded plasmid DNA in E. coli. The plasmid lacking an ssi signal accumulated much more plasmid single-stranded DNA than the wild-type plasmid did. Moreover, deletion of this region caused a great reduction in plasmid copy number or plasmid maintenance. These results suggest that in E. coli, this ssi signal directs its lagging-strand synthesis as a minus origin of plasmid pGKV21. Primer RNA synthesis in vitro suggests that E. coli RNA polymerase directly recognizes the 229-nt ssi signal and synthesizes primer RNA dependent on the presence of E. coli single-stranded DNA binding (SSB) protein. This region contains two stem-loop structures, stem-loop I and stem-loop II. Deletion of stem-loop I portion results in loss of priming activity by E. coli RNA polymerase, suggesting that stem-loop I portion is essential for priming by E. coli RNA polymerase on the SSB-coated single-stranded DNA template.open5
An expression signature of the angiogenic response in gastrointestinal neuroendocrine tumours: correlation with tumour phenotype and survival outcomes.
BACKGROUND: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are heterogeneous with respect to biological behaviour and prognosis. As angiogenesis is a renowned pathogenic hallmark as well as a therapeutic target, we aimed to investigate the prognostic and clinico-pathological role of tissue markers of hypoxia and angiogenesis in GEP-NETs. METHODS: Tissue microarray (TMA) blocks were constructed with 86 tumours diagnosed from 1988 to 2010. Tissue microarray sections were immunostained for hypoxia inducible factor 1α (Hif-1α), vascular endothelial growth factor-A (VEGF-A), carbonic anhydrase IX (Ca-IX) and somatostatin receptors (SSTR) 1–5, Ki-67 and CD31. Biomarker expression was correlated with clinico-pathological variables and tested for survival prediction using Kaplan–Meier and Cox regression methods. RESULTS: Eighty-six consecutive cases were included: 51% male, median age 51 (range 16–82), 68% presenting with a pancreatic primary, 95% well differentiated, 51% metastatic. Higher grading (P=0.03), advanced stage (P<0.001), high Hif-1α and low SSTR-2 expression (P=0.03) predicted for shorter overall survival (OS) on univariate analyses. Stage, SSTR-2 and Hif-1α expression were confirmed as multivariate predictors of OS. Median OS for patients with SSTR-2+/Hif-1α-tumours was not reached after median follow up of 8.8 years, whereas SSTR-2-/Hif-1α+ GEP-NETs had a median survival of only 4.2 years (P=0.006). CONCLUSION: We have identified a coherent expression signature by immunohistochemistry that can be used for patient stratification and to optimise treatment decisions in GEP-NETs independently from stage and grading. Tumours with preserved SSTR-2 and low Hif-1α expression have an indolent phenotype and may be offered less aggressive management and less stringent follow up
The Escherichia coli transcriptome mostly consists of independently regulated modules
Underlying cellular responses is a transcriptional regulatory network (TRN) that modulates gene expression. A useful description of the TRN would decompose the transcriptome into targeted effects of individual transcriptional regulators. Here, we apply unsupervised machine learning to a diverse compendium of over 250 high-quality Escherichia coli RNA-seq datasets to identify 92 statistically independent signals that modulate the expression of specific gene sets. We show that 61 of these transcriptomic signals represent the effects of currently characterized transcriptional regulators. Condition-specific activation of signals is validated by exposure of E. coli to new environmental conditions. The resulting decomposition of the transcriptome provides: a mechanistic, systems-level, network-based explanation of responses to environmental and genetic perturbations; a guide to gene and regulator function discovery; and a basis for characterizing transcriptomic differences in multiple strains. Taken together, our results show that signal summation describes the composition of a model prokaryotic transcriptome
Localized microstimulation of primate pregenual cingulate cortex induces negative decision-making
The pregenual anterior cingulate cortex (pACC) has been implicated in human anxiety disorders and depression, but the circuit-level mechanisms underlying these disorders are unclear. In healthy individuals, the pACC is involved in cost-benefit evaluation. We developed a macaque version of an approach-avoidance decision task used to evaluate anxiety and depression in humans and, with multi-electrode recording and cortical microstimulation, we probed pACC function as monkeys performed this task. We found that the macaque pACC has an opponent process-like organization of neurons representing motivationally positive and negative subjective value. Spatial distribution of these two neuronal populations overlapped in the pACC, except in one subzone, where neurons with negative coding were more numerous. Notably, microstimulation in this subzone, but not elsewhere in the pACC, increased negative decision-making, and this negative biasing was blocked by anti-anxiety drug treatment. This cortical zone could be critical for regulating negative emotional valence and anxiety in decision-making.National Institutes of Health (U.S.) (Javits Merit Grant R01 NS025529)United States. Office of Naval Research (N000140710903)National Parkinson Foundation (U.S.) (Lynn Diamond Fellowship
Proteins identification of wheat-rye translocation lines by MALDI-TOF-TOF mass spectrometry and ESI-QTOF/MS
Proteins identification of wheat-rye translocation lines by MALDI-TOF-TOF mass spectrometry and ESI-QTOF/MS
OBJECTIVE: To examine the relationship between Timed Up and Go (TUG) performance, verbal executive function (EF) performance, and quality-of-life (QOL) measures in Parkinson's disease (PD). DESIGN: Cross-sectional. SETTING: Sixteen movement disorder centers from across the United States. PARTICIPANTS: Patients with PD (N=1964). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: TUG test, immediate and delayed 5-word recall, verbal fluency, PD QOL Questionnaire. RESULTS: TUG performance and verbal EF performance were significantly associated with, and predictors of, QOL measures, having the greatest association and predictability with the mobility domain of the QOL measures. CONCLUSIONS: The TUG test and verbal EF tests have QOL correlates, making the combined evaluation of mobility, cognitive, and QOL decline a potential examination tool to evaluate the sequelae of PD
Controlled Orientation of Active Sites in a Nanostructured Multienzyme Complex
Multistep cascade reactions in nature maximize reaction efficiency by co-assembling related enzymes. Such organization facilitates the processing of intermediates by downstream enzymes. Previously, the studies on multienzyme nanocomplexes assembled on DNA scaffolds demonstrated that closer interenzyme distance enhances the overall reaction efficiency. However, it remains unknown how the active site orientation controlled at nanoscale can have an effect on multienzyme reaction. Here, we show that controlled alignment of active sites promotes the multienzyme reaction efficiency. By genetic incorporation of a non-natural amino acid and two compatible bioorthogonal chemistries, we conjugated mannitol dehydrogenase to formate dehydrogenase with the defined active site arrangement with the residue-level accuracy. The study revealed that the multienzyme complex with the active sites directed towards each other exhibits four-fold higher relative efficiency enhancement in the cascade reaction and produces 60% more D-mannitol than the other complex with active sites directed away from each other.ope
Lipid-Core Plaque Assessed by Near-Infrared Spectroscopy and Procedure Related Microvascular Injury
BACKGROUND AND OBJECTIVES: Microvascular damage due to distal embolization during percutaneous coronary intervention (PCI) is an important cause of periprocedural myocardial infarction. We assessed the lipid-core plaque using near-infrared spectroscopy (NIRS) and microvascular dysfunction invasively with the index of microcirculatory resistance (IMR) and evaluated their relationship.
METHODS: This study is pilot retrospective observational study. We analyzed 39 patients who performed NIRS before and after PCI, while fractional flow reserve, thermo-dilution coronary flow reserve (CFR) and IMR were measured after PCI. The maximum value of lipid core burden index (LCBI) for any of the 4-mm segments at the culprit lesion (culprit LCBI4mm) was calculated at the culprit lesion. We divided the patients into 2 groups using a cutoff of culprit LCBI4mm >/=500.
RESULTS: Mean pre-PCI LCBI was 333+/-196 and mean post-PCI IMR was 20+/-14 U. Post-PCI IMR was higher (15.6+/-7.3 vs. 42.6+/-17.6 U, p/=25 U) was higher in the high LCBI group (9.4% vs. 85.7%, p<0.001). However, there were no significant differences in the incidences of creatine Kinase-MB (9.4% vs. 14.3%, p=0.563) and troponin-I elevation (12.5% vs. 14.3%, p=1.000).
CONCLUSIONS: A large lipid-core plaque at the 'culprit' lesion is observed higher incidence of post-PCI microvascular dysfunction after PCI. Prospective study with adequate subject numbers will be needed
Stent dislodgement force of drug-eluting coronary stents: a bench test
BACKGROUND: Coronary stent dislodgement can cause critical complications. The dislodgement force of coronary drug-eluting stents (DES) remains unknown. This study aimed to compare the dislodgement force and pattern of contemporary DES. METHODS: Five DES designs which commonly used in clinical practice were tested. The force at which the stent dislodges relative to the balloon was measured. For the shim test, peak displacement force, defined as the first peak force that occurs during stent displacement and peak dislodgement force, defined as the peak force required to completely dislodge the stent from the delivery system, were measured. Three examples of each of the stents were tested using the shim test. RESULTS: The peak displacement force of Orsiro (3.1+/-0.8 N) was lower than that of Xience Sierra (5.8+/-0.5 N) [Firehawk 3.8+/-0.2 N, Resolute Onyx 4.5+/-1.5 N, Synergy 4.8+/-0.5 N (P=0.024)]. The peak dislodgement force was lowest in Orsiro (3.2+/-0.8 N) when compared to the other stents (Firehawk 6.6+/-0.6 N, Resolute Onyx 7.4+/-0.3 N, Synergy 11.8+/-0.4 N, Xience Sierra 11.1+/-1.6 N) (P<0.001); this remained significant in the multiple comparison analysis. During pullback of the stents, most stents buckled without removal. However, the whole Orsiro stent was completely removed from the delivery system. CONCLUSIONS: The dislodgement force of DESs differed between stent designs. The Orsiro stent was lower than that of other DES; additionally, it easily removed the whole stent from the delivery system. During the coronary intervention, operators should consider stent design and be cautious when pulling DES back in lesions with calcifications or a previously implanted stent, which are at high risk for stent dislodgement
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