81 research outputs found
Tool flow management in batch manufacturing systems for cylindrical components
The objective of the research is to study the design of and operating strategies
for advanced tool flow systems in highly automated turning systems. A prototype
workstation has been built to aid this process. The thesis consists of three main
parts. In the first part the current flexible manufacturing technology is reviewed
with emphasis laid on tool flow and production scheduling problems. The
'State-of-the-Art' turning systems are studied, to highlight the requirement of the
computer modelling of tool flow systems.
In the second part, the design of a computer model using fast modelling
algorithms is reported. The model design has concentrated on the tool flow system performance forecasting and improving. Attention has been given to the full
representation of highly automatic features evident in turning systems.
A number of contemporary production scheduling rules have been
incorporated into the computer model structure, with the objectives of providing a
frontend to the tool flow model, and to examine the tool flow problems
interactively with the production scheduling rules.
The user-interface of the model employs conversational type screens for tool
flow network specification and data handling, which enhances its user friendliness
greatly. An effective, fast, and easy to handle data base management system for
tool, part, machine data entries has been· built up to facilitate the model
performance.
The third part of the thesis is concerned with the validation and application of
the model with industry supplied data to examine system performance, and to
evaluate alternative strategies. Conclusions drawn from this research and the
recommendations for further work are finally indicated
Data_Sheet_1_The effect of small incision lenticule extraction on contrast sensitivity.docx
The improvements due to small incision lenticule extraction (SMILE) in vision, e.g., in spherical equivalent (SE) and visual acuity (VA), has been widely recognized. However, the contrast sensitivity (CS) change after SMILE was not certain. Here, we investigated the effect of SMILE on CS before, 1 day after and 7 days after surgery and then clarified the corresponding mechanism by using a perceptual template model (PTM). In addition, the relationship among SE, VA, and CS was discussed. The quick contrast sensitivity function (qCSF) was applied to measure CS with high precision and accuracy. We found that (1) CS was significantly improved 1 day after SMILE and was also increased 7 days after the surgery, (2) CS improvements were dependent on spatial frequency and external noise, (3) the increase in CS was due to the decreased internal additive noise and an enhanced perceptual template, and (4) Greater SE improvements predicted better VA improvements 1 day after SMILE, and a positive correlation between SE improvements and AULCSF improvements 7 days after SMILE was observed. These findings help us better understand the effect of SMILE and provide effective indicators for future visual research.</p
Image_1_MsTHI1 overexpression improves drought tolerance in transgenic alfalfa (Medicago sativa L.).TIF
In recent years, drought stress caused by global warming has become a major constraint on agriculture. The thiamine thiazole synthase (THI1) is responsible for controlling thiamine production in plants displaying a response to various abiotic stresses. Nonetheless, most of the THI1 activities in plants remain largely unknown. In this study, we extracted MsTHI1 from alfalfa and demonstrated its beneficial impact on improving the resistance of plants to stress conditions. The highest levels of MsTHI1 expression were identified in alfalfa leaves, triggered by exposure to cold, drought, salt, or alkaline conditions. The upregulation of MsTHI1 in drought-stressed transgenic plants resulted in enhanced accumulation of vitamin B1 (VB1), chlorophyll a (Chl a), chlorophyll b (Chl b), soluble protein, higher soil and plant analyzer development (SPAD) value, and the activity of peroxidase (POD), maintained Fv/Fm, and decreased lipid peroxidation. Moreover, overexpression of MsTHI1 upregulated the transcription of THI4, TPK1, RbcX2, Cu/Zn-SOD, CPK13, and CPK32 and downregulated the transcription of TH1 and CPK17 in transgenic alfalfa under drought stress. These results suggested that MsTHI1 enhances drought tolerance by strengthening photosynthesis, regulating the antioxidant defense system, maintaining osmotic homeostasis, and mediating plant signal transduction.</p
Image_1_Axillary management in patients with clinical node-negative early breast cancer and positive sentinel lymph node: a systematic review and meta-analysis.tif
BackgroundThe omission of axillary lymph node dissection (ALND) or axillary radiation (AxRT) remains controversial in patients with clinical node-negative early breast cancer and a positive sentinel lymph node.MethodsWe conducted a comprehensive review by searching PubMed, Embase, Web of Science, and Cochrane databases (up to November 2023). Our primary outcomes were overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and axillary recurrence (AR).ResultsWe included 26 studies encompassing 145,548 women with clinical node-negative early breast cancer and positive sentinel lymph node. Pooled data revealed no significant differences between ALND and sentinel lymph node biopsy (SLNB) alone in terms of OS (hazard ratio [HR]0.99, 95% confidence interval [CI] 0.91-1.08, p=0.84), DFS (HR 1.04, 95% CI 0.90-1.19, p=0.61), LRR (HR 0.76, 95% CI 0.45-1.20, p=0.31), and AR (HR 1.01, 95% CI 0.99-1.03, p=0.35). Similarly, no significant differences were observed between AxRT and SLNB alone for OS (HR 0.57, 95% CI 0.32-1.02, p=0.06) and DFS (HR 0.52, 95% CI 0.26-1.05, p=0.07). When comparing AxRT and ALND, a trend towards higher OS was observed the AxRT group (HR 0.08, 95% CI 0.67-1.15), but the difference did not reach statistical significance (p=0.35, I2Â =Â 0%). Additionally, no significant differences significance observed for DFS or AR (p=0.13 and p=0.73, respectively) between the AxRT and ALND groups.ConclusionOur findings suggest that survival and recurrence rates are not inferior in patients with clinical node-negative early breast cancer and a positive sentinel lymph node who receive SLNB alone compared to those undergoing ALND or AxRT.</p
Table_1_MsTHI1 overexpression improves drought tolerance in transgenic alfalfa (Medicago sativa L.).DOCX
In recent years, drought stress caused by global warming has become a major constraint on agriculture. The thiamine thiazole synthase (THI1) is responsible for controlling thiamine production in plants displaying a response to various abiotic stresses. Nonetheless, most of the THI1 activities in plants remain largely unknown. In this study, we extracted MsTHI1 from alfalfa and demonstrated its beneficial impact on improving the resistance of plants to stress conditions. The highest levels of MsTHI1 expression were identified in alfalfa leaves, triggered by exposure to cold, drought, salt, or alkaline conditions. The upregulation of MsTHI1 in drought-stressed transgenic plants resulted in enhanced accumulation of vitamin B1 (VB1), chlorophyll a (Chl a), chlorophyll b (Chl b), soluble protein, higher soil and plant analyzer development (SPAD) value, and the activity of peroxidase (POD), maintained Fv/Fm, and decreased lipid peroxidation. Moreover, overexpression of MsTHI1 upregulated the transcription of THI4, TPK1, RbcX2, Cu/Zn-SOD, CPK13, and CPK32 and downregulated the transcription of TH1 and CPK17 in transgenic alfalfa under drought stress. These results suggested that MsTHI1 enhances drought tolerance by strengthening photosynthesis, regulating the antioxidant defense system, maintaining osmotic homeostasis, and mediating plant signal transduction.</p
Dual Activation Strategy to Achieve C–C Cleavage of Cyclobutanes: Development and Mechanism of Rh and Zn Cocatalyzed [4 + 2] Cycloaddition of Yne-Vinylcyclobutanones
Reported here is the Rh and Zn cocatalyzed [4 + 2] cycloaddition
of newly designed yne-vinylcyclobutanones, which can generate 5/6
or 6/6 bicyclic products with an all-carbon quaternary bridgehead
center. The reaction has a broad scope and can realize chirality transfer
from enantioenriched substrates to the cycloadducts. The key to the
success of this [4 + 2] reaction is the introduction of a vinyl group
to cyclobutanones, which helps the C–C cleavage of vinylcyclobutanones
via oxidative addition. This C–C cleavage step is synergistically
aided by Zn coordination to the carbonyl group of vinylcyclobutanones.
Of the same importance, visual kinetic analysis and computational
studies have been carried out to support the dual activation in the
rate-determining C–C cleavage, to derive the rate law of the
[4 + 2] reaction, to understand another role of Zn in helping the
in situ generation of the cationic Rh catalyst and preventing catalyst
deactivation, and to analyze the key transition states and intermediates
involved
Image_2_MsTHI1 overexpression improves drought tolerance in transgenic alfalfa (Medicago sativa L.).TIF
In recent years, drought stress caused by global warming has become a major constraint on agriculture. The thiamine thiazole synthase (THI1) is responsible for controlling thiamine production in plants displaying a response to various abiotic stresses. Nonetheless, most of the THI1 activities in plants remain largely unknown. In this study, we extracted MsTHI1 from alfalfa and demonstrated its beneficial impact on improving the resistance of plants to stress conditions. The highest levels of MsTHI1 expression were identified in alfalfa leaves, triggered by exposure to cold, drought, salt, or alkaline conditions. The upregulation of MsTHI1 in drought-stressed transgenic plants resulted in enhanced accumulation of vitamin B1 (VB1), chlorophyll a (Chl a), chlorophyll b (Chl b), soluble protein, higher soil and plant analyzer development (SPAD) value, and the activity of peroxidase (POD), maintained Fv/Fm, and decreased lipid peroxidation. Moreover, overexpression of MsTHI1 upregulated the transcription of THI4, TPK1, RbcX2, Cu/Zn-SOD, CPK13, and CPK32 and downregulated the transcription of TH1 and CPK17 in transgenic alfalfa under drought stress. These results suggested that MsTHI1 enhances drought tolerance by strengthening photosynthesis, regulating the antioxidant defense system, maintaining osmotic homeostasis, and mediating plant signal transduction.</p
Image_2_Axillary management in patients with clinical node-negative early breast cancer and positive sentinel lymph node: a systematic review and meta-analysis.tif
BackgroundThe omission of axillary lymph node dissection (ALND) or axillary radiation (AxRT) remains controversial in patients with clinical node-negative early breast cancer and a positive sentinel lymph node.MethodsWe conducted a comprehensive review by searching PubMed, Embase, Web of Science, and Cochrane databases (up to November 2023). Our primary outcomes were overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and axillary recurrence (AR).ResultsWe included 26 studies encompassing 145,548 women with clinical node-negative early breast cancer and positive sentinel lymph node. Pooled data revealed no significant differences between ALND and sentinel lymph node biopsy (SLNB) alone in terms of OS (hazard ratio [HR]0.99, 95% confidence interval [CI] 0.91-1.08, p=0.84), DFS (HR 1.04, 95% CI 0.90-1.19, p=0.61), LRR (HR 0.76, 95% CI 0.45-1.20, p=0.31), and AR (HR 1.01, 95% CI 0.99-1.03, p=0.35). Similarly, no significant differences were observed between AxRT and SLNB alone for OS (HR 0.57, 95% CI 0.32-1.02, p=0.06) and DFS (HR 0.52, 95% CI 0.26-1.05, p=0.07). When comparing AxRT and ALND, a trend towards higher OS was observed the AxRT group (HR 0.08, 95% CI 0.67-1.15), but the difference did not reach statistical significance (p=0.35, I2Â =Â 0%). Additionally, no significant differences significance observed for DFS or AR (p=0.13 and p=0.73, respectively) between the AxRT and ALND groups.ConclusionOur findings suggest that survival and recurrence rates are not inferior in patients with clinical node-negative early breast cancer and a positive sentinel lymph node who receive SLNB alone compared to those undergoing ALND or AxRT.</p
Steady-state kinetic parameters of <i>C. glutamicum</i> Mca mutants for <i>N</i>-deacetylation of <i>N</i>-acetyl-D-glucosamine (GlcNAc).
<p>Assays were performed in the presence of 10 µM enzyme and 0–5.0 mM GlcNAc in 50 mM HEPES (pH 7.5) at 30°C.</p><p>Steady-state kinetic parameters of <i>C. glutamicum</i> Mca mutants for <i>N</i>-deacetylation of <i>N</i>-acetyl-D-glucosamine (GlcNAc).</p
Image_3_Leymus chinensis resists degraded soil stress by modulating root exudate components to attract beneficial microorganisms.TIF
Phytoremediation is an effective means to improve degraded soil nutrients and soil structure. Here, we investigated the remediation effects of Leymus chinensis on the physicochemical properties and structure of degraded soil after 3 years of cultivation and explored the bacterial and fungal drivers in root exudates by metabolomics and high-throughput sequencing. The results showed that root exudates increased soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP) and soil aggregates, and organic acids in root exudates reduced pH and activated insoluble nutrients into forms that are available to plants, such as available nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), and available phosphorus (AP). The cultivation of L. chinensis restored the diversity and richness of soil microorganisms and recruited potential beneficial bacteria and fungi to resist degraded soil stress, and L. chinensis also regulated the abundances of organic acids, amino acids and fatty acids in root exudates to remediate degraded soils. Spearman correlation analysis indicated that glutaric acid, 3-hydroxybutyric acid and 4-methylcatechol in root exudates attracted Haliangium, Nitrospira and Mortierella to the rhizosphere and dispersed the relative abundance of the harmful microorganisms Fusicolla and Fusarium. Our results demonstrate that L. chinensis enhances soil fertility, improves soil structure, promotes microbial diversity and abundance, and recruits potentially beneficial microorganisms by modulating root exudate components.</p
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