465 research outputs found
The Friedberg-Lee model at finite temperature and density
The Friedberg-Lee model is studied at finite temperature and density. By
using the finite temperature field theory, the effective potential of the
Friedberg-Lee model and the bag constant and have been
calculated at different temperatures and densities. It is shown that there is a
critical temperature when
and a critical chemical potential for fixing
the temperature at . We also calculate the soliton solutions
of the Friedberg-Lee model at finite temperature and density. It turns out that
when (or ), there is a bag constant (or
) and the soliton solutions are stable. However, when (or
) the bag constant (or ) and there is no soliton solution anymore, therefore, the
confinement of quarks disappears quickly.Comment: 12 pages, 11 figures; version accepted for publication in Phys. Rev.
Contrast-free detection of myocardial fibrosis in hypertrophic cardiomyopathy patients with diffusion-weighted cardiovascular magnetic resonance.
BackgroundsPrevious studies have shown that diffusion-weighted cardiovascular magnetic resonance (DW-CMR) is highly sensitive to replacement fibrosis of chronic myocardial infarction. Despite this sensitivity to myocardial infarction, DW-CMR has not been established as a method to detect diffuse myocardial fibrosis. We propose the application of a recently developed DW-CMR technique to detect diffuse myocardial fibrosis in hypertrophic cardiomyopathy (HCM) patients and compare its performance with established CMR techniques.MethodsHCM patients (N = 23) were recruited and scanned with the following protocol: standard morphological localizers, DW-CMR, extracellular volume (ECV) CMR, and late gadolinium enhanced (LGE) imaging for reference. Apparent diffusion coefficient (ADC) and ECV maps were segmented into 6 American Heart Association (AHA) segments. Positive regions for myocardial fibrosis were defined as: ADC > 2.0 μm(2)/ms and ECV > 30%. Fibrotic and non-fibrotic mean ADC and ECV values were compared as well as ADC-derived and ECV-derived fibrosis burden. In addition, fibrosis regional detection was compared between ADC and ECV calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) using ECV as the gold-standard reference.ResultsADC (2.4 ± 0.2 μm(2)/ms) of fibrotic regions (ADC > 2.0 μm(2)/ms) was significantly (p < 0.01) higher than ADC (1.5 ± 0.2 μm(2)/ms) of non-fibrotic regions. Similarly, ECV (35 ± 4%) of fibrotic regions (ECV > 30%) was significantly (p < 0.01) higher than ECV (26 ± 2%) of non-fibrotic regions. In fibrotic regions defined by ECV, ADC (2.2 ± 0.3 μm(2)/ms) was again significantly (p < 0.05) higher than ADC (1.6 ± 0.3 μm(2)/ms) of non-fibrotic regions. In fibrotic regions defined by ADC criterion, ECV (34 ± 5%) was significantly (p < 0.01) higher than ECV (28 ± 3%) in non-fibrotic regions. ADC-derived and ECV-derived fibrosis burdens were in substantial agreement (intra-class correlation = 0.83). Regional detection between ADC and ECV of diffuse fibrosis yielded substantial agreement (κ = 0.66) with high sensitivity, specificity, PPV, NPV, and accuracy (0.80, 0.85, 0.81, 0.85, and 0.83, respectively).ConclusionDW-CMR is sensitive to diffuse myocardial fibrosis and is capable of characterizing the extent of fibrosis in HCM patients
Dynamic changes in transcripts during regeneration of the secondary vascular system in Populus tomentosa Carr. revealed by cDNA microarrays
<p>Abstract</p> <p>Background</p> <p>Wood is the end product of secondary vascular system development, which begins from the cambium. The wood formation process includes four major stages: cell expansion, secondary wall biosynthesis, lignification, and programmed cell death. Transcriptional profiling is a rapid way to screen for genes involved in these stages and their transitions, providing the basis for understanding the molecular mechanisms that control this process.</p> <p>Results</p> <p>In this study, cDNA microarrays were prepared from a subtracted cDNA library (cambium zone <it>versus </it>leaf) of Chinese white poplar (<it>Populus tomentosa </it>Carr.) and employed to analyze the transcriptional profiles during the regeneration of the secondary vascular system, a platform established in our previous study. Two hundred and seven genes showed transcript-level differences at the different regeneration stages. Dramatic transcriptional changes were observed at cambium initiation, cambium formation and differentiation, and xylem development, suggesting that these up- or downregulated genes play important roles in these stage transitions. Transcription factors such as AUX/IAA and PINHEAD, which were previously shown to be involved in meristem and vascular tissue differentiation, were strongly transcribed at the stages when cambial cells were initiated and underwent differentiation, whereas genes encoding MYB proteins and several small heat shock proteins were strongly transcribed at the stage when xylem development begins.</p> <p>Conclusion</p> <p>Employing this method, we observed dynamic changes in gene transcript levels at the key stages, including cambium initiation, cambium formation and differentiation, and xylem development, suggesting that these up- or downregulated genes are strongly involved in these stage transitions. Further studies of these genes could help elucidate their roles in wood formation.</p
Transcriptome, microRNA, and degradome analyses of the gene expression of Paulownia with phytoplamsa
Primers of P. tomentosa miRNAs for qRT-PCR analysis. (DOCX 20.7 kb
Involvement of C2H2 zinc finger proteins in the regulation of epidermal cell fate determination in Arabidopsis
Cell fate determination is a basic developmental process during the growth of multicellular organisms. Trichomes and root hairs of Arabidopsis are both readily accessible structures originating from the epidermal cells of the aerial tissues and roots respectively, and they serve as excellent models for understanding the molecular mechanisms controlling cell fate determination and cell morphogenesis. The regulation of trichome and root hair formation is a complex program that consists of the integration of hormonal signals with a large number of transcriptional factors, including MYB and bHLH transcriptional factors. Studies during recent years have uncovered an important role of C2H2 type zinc finger proteins in the regulation of epidermal cell fate determination. Here in this minireview we briefly summarize the involvement of C2H2 zinc finger proteins in the control of trichome and root hair formation in Arabidopsis .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109574/1/jipb12221.pd
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The role of imaging in 2019 novel coronavirus pneumonia (COVID-19).
Almost the entire world, not only China, is currently experiencing the outbreak of a novel coronavirus that causes respiratory disease, severe pneumonia, and even death. The outbreak began in Wuhan, China, in December of 2019 and is currently still ongoing. This novel coronavirus is highly contagious and has resulted in a continuously increasing number of infections and deaths that have already surpassed the SARS-CoV outbreak that occurred in China between 2002 and 2003. It is now officially a pandemic, announced by WHO on the 11th of March. Currently, the 2019 novel coronavirus (SARS-CoV-2) can be identified by virus isolation or viral nucleic acid detection; however, false negatives associated with the nucleic acid detection provide a clinical challenge and thus make the imaging examination crucial. Imaging exams have been a main clinical diagnostic criteria for the 2019 novel coronavirus disease (COVID-19) in China. Imaging features of multiple patchy areas of ground glass opacity and consolidation predominately in the periphery of the lungs are characteristic manifestations on chest CT and extremely helpful in the early detection and diagnosis of this disease, which aids prompt diagnosis and the eventual control of this emerging global health emergency. Key Points • In December 2019, China, an outbreak of pneumonia caused by a novel, highly contagious coronavirus raised grave concerns and posed a huge threat to global public health. • Among the infected patients, characteristic findings on CT imaging include multiple, patchy, ground-glass opacity, crazy-paving pattern, and consolidation shadows, mainly distributed in the peripheral and subpleural areas of both lungs, which are very helpful for the frontline clinicians. • Imaging examination has become the indispensable means not only in the early detection and diagnosis but also in monitoring the clinical course, evaluating the disease severity, and may be presented as an important warning signal preceding the negative RT-PCR test results
Microencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery
Xiang Li1, Nicolas Anton1, Thi Minh Chau Ta1, Minjie Zhao2, Nadia Messaddeq3, Thierry F Vandamme11University of Strasbourg, Faculty of Pharmacy, UMR CNRS 7199 Laboratory of Conception and Application of Bioactive Molecules (Biogalenic Pharmacy team); 2University of Strasbourg, Faculty of Pharmacy, CNRS UMR 7178, IPHC, Laboratory of Analytic Chemistry and Food Science; 3Institute of Genetics and Molecular and Cellular Biology (IGBMC), UMR University of Strasbourg/CNRS/INSERM/Coll&egrave;ge de France, Illkirch, FranceBackground: Nanoemulsions consist of very stable nanodroplets of oil dispersed in an aqueous phase, typically below 300 nm in size. They can be used to obtain a very fine, homogeneous dispersion of lipophilic compounds in water, thus facilitating their handling and use in nanomedicine. However, the drawback is that they are suspended in an aqueous media. This study proposes a novel technique for drying lipid nanoemulsion suspensions to create so-called Trojan particles, ie, polymer microparticles (around 2 &micro;m) which very homogeneously &ldquo;entrap&rdquo; the nano-oil droplets (around 150 nm) in their core.Methods: Microencapsulation of the nanoemulsions was performed using a spray-drying process and resulted in a dried powder of microparticles. By using a low-energy nanoemulsification method and relatively gentle spray-drying, the process was well suited to sensitive molecules. The model lipophilic molecule tested was vitamin E acetate, encapsulated at around 20% in dried powder.Results: We showed that the presence of nanoemulsions in solution before spray-drying had a significant impact on microparticle size, distribution, and morphology. However, the process itself did not destroy the oil nanodroplets, which could easily be redispersed when the powder was put back in contact with water. High-performance liquid chromatography follow-up of the integrity of the vitamin E acetate showed that the molecules were intact throughout the process, as well as when conserved in their dried form.Conclusion: This study proposes a novel technique using a spray-drying process to microencapsulate nanoemulsions. The multiscale object formed, so-called Trojan microparticles, were shown to successfully encapsulate, protect, and release the lipid nanodroplets.Keywords: nanoemulsions, microparticles, Trojan particle, spray-drying, low-energy emulsification, vitamin E acetat
Diagnostic Accuracy of Three-Dimensional Whole-Heart Magnetic Resonance Angiography to Detect Coronary Artery Disease with Invasive Coronary Angiography as a Reference: A Meta-Analysis
Objective: We aimed to evaluate the diagnostic performance of three-dimensional whole-heart magnetic resonance coronary angiography (MRCA) in detecting coronary artery disease (CAD) with invasive coronary angiography as the reference standard. Methods: We searched PubMed and Embase for studies evaluating the diagnostic performance of three-dimensional whole-heart MRCA for the diagnosis of CAD with invasive coronary angiography as the reference standard. The bivariate mixed-effects regression model was applied to synthesize available data. The clinical utility of whole-heart MRCA was calculated by the posttest probability based on Bayes’s theorem. Results: Eighteen studies were included, of which 16 provided data at the artery level. Patient-based analysis revealed a pooled sensitivity of 0.90 (95% confidence interval [CI] 0.87–0.93) and specificity of 0.79 (95% CI 0.73–0.84), while the pooled estimates were 0.86 (95% CI 0.82–0.89) and 0.89 (95% CI 0.84–0.92), respectively, at the artery level. The areas under the summary receiver operating characteristic curve were 0.93 (95% CI 0.90–0.95) and 0.92 (95% CI 0.90–0.94) at the patient and artery levels, respectively. With a pretest probability of 50%, the patients’ posttest probabilities of CAD were 81% for positive results and 11% for negative results. Conclusions: Whole-heart MRCA can be an alternative noninvasive method for diagnosis and assessment of CAD
Icacina senegalensis (Icacinaceae), traditionally used for the treatment of malaria, inhibits in vitro Plasmodium falciparum growth without host cell toxicity
<p>Abstract</p> <p>Background</p> <p>With the aim of discovering new natural active extracts against malaria parasites, <it>Icacina senegalensis </it>was selected after an ethnopharmacological survey conducted on plants used in traditional malaria treatment in Senegal.</p> <p>Methods</p> <p>Different concentrations of the plant extract and fractions were tested on synchronized <it>Plasmodium falciparum </it>cultures at the ring stage using the parasite lactate dehydrogenase assay. Their haemolytic activity and <it>in vitro </it>cytoxicity were evaluated. The chromatographic profiles of active fractions were also established.</p> <p>Results</p> <p>The plant extract and fractions revealed anti-plasmodial activity (IC<sub>50 </sub>< 5 μg/mL) with no toxicity (Selectivity indexes >10). The dichloromethane fraction showed stronger anti-plasmodial activity than the total extract.</p> <p>Conclusion</p> <p>Anti-plasmodial activity and toxicity of <it>I. senegalensis </it>are reported for the first time and showed promising results in malaria field research.</p
Serum uric acid as a predictor of mortality in patients with stroke: results from National Health and Nutrition Examination Survey 2007–2016
ObjectiveThis research endeavors to explore the relationship between serum uric acid (SUA) concentration and all-cause mortality in stroke patients.MethodsWe undertook a cross-sectional analysis utilizing data derived from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2016. The concentrations of SUA served as the independent variable, while the dependent variable was defined as all-cause mortality in stroke patients. The quartile method was utilized to classify uric acid levels into four distinct categories. Subsequently, three models were developed, and Cox proportional hazards regression was used to assess the effect of varying uric acid concentrations on the risk of all-cause mortality among stroke patients.ResultsThe study included a total of 10,805 participants, of whom 395 were stroke patients. Among all populations, the group with elevated levels of uric acid (Q4) exhibited a significant association with the overall mortality risk among stroke patients in all three models (model 1 p < 0.001, model 2 p < 0.001, model 3 p < 0.001). In the male population, there was no significant correlation observed between uric acid levels and the overall mortality risk among stroke patients in model 3 (Q2 p = 0.8, Q3 p = 0.2, Q4 p = 0.2). However, within the female population, individuals with high uric acid levels (Q4) demonstrated a noteworthy association with the overall mortality risk among stroke patients across all three models (model 1 p < 0.001, model 2 p < 0.001, model 3 p < 0.001).ConclusionThis cross-sectional investigation reveals a significant correlation between SUA levels and all-cause mortality in stroke patients, with a noticeable trend observed among females. Consequently, SUA may serve as a promising biomarker for assessing the prognosis of individuals affected by stroke
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