3,605 research outputs found
Electrospun nanosized cellulose fibers using ionic liquids at room temperature
Aiming at replacing the noxious solvents commonly employed, ionic-liquid-based solvents have been recently explored as novel non-volatile and non-flammable media for the electrospinning of polymers. In this work, nanosized and biodegradable cellulose fibers were obtained by electrospinning at room temperature using a pure ionic liquid or a binary mixture of two selected ionic liquids. The electrospinning of 8 wt% cellulose in 1-ethyl-3-methylimidazolium acetate medium (a low viscosity and room temperature ionic liquid capable of efficiently dissolving cellulose) showed to produce electrospun fibers with average diameters within (470 Âą 110) nm. With the goal of tailoring the surface tension of the spinning dope, a surface active ionic liquid was further added in a 0.10 : 0.90 mole fraction ratio. Electrospun cellulose fibers from the binary mixture composed of 1-ethyl-3-methylimidazolium acetate and 1-decyl-3-methylimidazolium chloride ionic liquids presented average diameters within (120 Âą 55) nm. Scanning electron microscopy, X-ray diffraction analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric assays were used as core methods to evaluate the structural integrity, morphology and crystallinity of the raw, electrospun, and regenerated samples of cellulose. Moreover, the photoluminescence spectra of both raw and electrospun fibers were acquired, and compared, indicating that the cellulose emitting centers are not affected by the dissolution of cellulose in ionic liquids. Finally, the use of non-volatile solvents in electrospinning coupled to a water coagulation bath allows the recovery of the ionic fluid, and represents a step forward into the search of environmentally friendly alternatives to the conventional approaches
Case report: Fatal infantile hypertonic myofibrillar myopathy with compound heterozygous mutations in the CRYAB gene
BackgroundFatal infantile hypertonic myofibrillar myopathy (FIHMM) is an autosomal recessive hereditary disease characterized by amyotrophy, progressive flexion contracture and ankylosis of the trunk and limb muscles, apnea and respiratory failure, and increased creatine phosphate levels. It is caused by mutations in the CRYAB gene, and only around 18 cases including genetic mutations have been reported worldwide. All patients with FIHMM develop respiratory distress, progressive stiffness of the limbs, and have a poor prognosis. However, no effective treatment for CRYAB-associated respiratory failure has been reported. Here, we report a case of FIHMM with a novel heterozygous missense mutation.Case PresentationA 2-year-old female developed scoliosis of the lumbar spine and restrictive ventilatory dysfunction in infancy. She was admitted to the hospital with labored breathing on the third day after the second injection of inactivated poliomyelitis vaccine. Acute respiratory failure, pneumothorax, and cardiac arrest arose in the patient during hospitalization, and progressive stiffness of the trunk and limb muscles appeared, accompanied by obvious abdominal distension and an increase in phosphocreatine kinase levels. Screenings for genetic metabolic diseases in the blood and urine were normal. Electromyography revealed mild myogenic damage. A muscle biopsy indicated the accumulation of desmin, Îą-crystallin, and myotilin in the musculus biceps brachii, and dense granules were observed in muscle fibers using electron microscopy. Mutation analysis of CRYAB revealed a novel heterozygous missense mutation in the proband, c.302Aâ>âC (p.His101Pro) and c.3Gâ>âA (p.Met1Ile), which inherited from her asymptomatic, heterozygous carrier parents, respectively. The proband was finally diagnosed as FIHMM. One month after the FIHMM diagnosis, the child died of respiratory failure.ConclusionWe report a case of FIHMM with a novel heterozygous missense mutation of CRYAB. This finding might improve our understanding of FIHMM and highlight a novel mutation in the Chinese population
Identification of host proteins interacting with Toxoplasma gondii GRA15 (TgGRA15) by yeast two-hybrid system
Background
Toxoplasma gondii, an obligate intracellular protozoan parasite, possesses the remarkable ability to co-opt host cell machinery in order to maintain its intracellular survival. This parasite can modulate signaling pathways of its host through the secretion of polymorphic effector proteins localized in the rhoptry and dense granule organelles. One of such effectors is T. gondii type II-specific dense granule protein 15, TgGRA15, which activates NF-ÎşB pathway. The aim of the present study was to identify the host interaction partner proteins of TgGRA15.
Methods
We screened a yeast two-hybrid mouse cDNA library using TgGRA15 as the bait. TgGRA15 (PRU strain, Type II) was cloned into the pGBKT7 vector and expressed in the Y2HGold yeast strain. Then, the bait protein expression was validated by western blotting analysis, followed by auto-activation and toxicity tests in comparison with control (Y2HGold yeast strain transformed with empty pGBKT7 vector).
Results
This screening led to the identification of mouse Luzp1 and AW209491 as host binding proteins that interact with TgGRA15. Luzp1 contains three nuclear localizing signals and is involved in regulating a subset of host non-coding RNA genes.
Conclusions
These findings reveal, for the first time, new host cell proteins interacting with TgGRA15. The identification of these cellular targets and the understanding of their contribution to the host-pathogen interaction may serve as the foundation for novel therapeutic and prevention strategies against T. gondii infection
Development and validation of a nomogram for assessing survival in patients with COVID-19 pneumonia
Background: The outbreak of coronavirus disease (COVID-19) in 2019 has spread worldwide and continues to cause great threat to peoplesâ health as well as put pressure on the accessibility of medical systems. Early prediction of survival of hospitalized patients will help the clinical management of COVID-19, but such a prediction model which is reliable and valid is still lacking.
Methods: We retrospectively enrolled 628 confirmed cases of COVID-19 using positive RT-PCR tests for SARS-CoV-2 in Tongji Hospital in Wuhan, China. These patients were randomly grouped into a training cohort (60%) and a validation cohort (40%). In the training cohort, least absolute shrinkage and selection operator (LASSO) regression analysis and multivariate Cox regression analysis were utilized to identify prognostic factors for in-hospital survival of patients with COVID-19. A nomogram based on the three variables was built for clinical use. Areas under the ROC curves (AUC), concordance index (C-index) and calibration curve were used to evaluate the efficiency of the nomogram in both the training and validation cohorts.
Results: Hypertension, higher neutrophil-to-lymphocyte ratio and increased NT-proBNP value were found to be significantly associated with poorer prognosis in hospitalized patients with COVID-19. The three predictors were further used to build a prediction nomogram. The C-index of the nomogram in the training and validation cohorts was 0.901 and 0.892, respectively. The AUC in the training cohort was 0.922 for 14- day and 0.919 for 21-day probability of in-hospital survival, while in the validation cohort was 0.922 and 0.881, respectively. Moreover, the calibration curve for 14- day and 21-day survival also showed high coherence between the predicted and actual probability of survival.
Conclusion: We managed to build a predictive model and constructed a nomogram for predicting in-hospital survival of patients with COVID-19. This model represents good performance and might be utilized clinically in the management of COVID-19.
Keywords:
Coronavirus; COVID-19; nomogram; prediction; surviva
Antibiotic prescribing for upper respiratory infections among children in rural China: a cross-sectional study of outpatient prescriptions
Background: Overuse of antibiotics contributes to the development of antimicrobial resistance. Objective: This study aims to assess the condition of antibiotic use at health facilities at county, township and village levels in rural Guangxi, China. Methods: We conducted a cross-sectional study of outpatient antibiotic prescriptions in 2014 for children aged 2â14 years with upper respiratory infections (URI). Twenty health facilities were randomly selected, including four county hospitals, eight township hospitals and eight village clinics. Prescriptions were extracted from the electronic records in the county hospitals and paper copies in the township hospitals and village clinics. Results: The antibiotic prescription rate was higher in township hospitals (593/877, 68%) compared to county hospitals (2736/8166, 34%) and village clinics (96/297, 32%) (p < 0.001). Among prescriptions containing antibiotics, county hospitals were found to have the highest use rate of broad-spectrum antibiotics (82 vs 57% [township], vs 54% [village], p < 0.001), injectable antibiotics (65 vs 43% [township], vs 33% [village], p < 0.001) and multiple antibiotics (47 vs 15% [township], vs 0% [village], p < 0.001). Logistic regression showed that the likelihood of prescribing an antibiotic was significantly associated with patients being 6â14 years old compared with being 2â5 years old (adjusted odds ratio [aOR] = 1.3, 95% CI 1.2â1.5), and receiving care at township hospitals compared with county hospitals (aOR = 5.0, 95% CI 4.1â6.0). Prescriptions with insurance copayment appeared to lower the risk of prescribing antibiotics compared with those without (aOR = 0.8, 95% CI 0.7â0.9). Conclusions: Inappropriate use of antibiotics was high for outpatient childhood URI in the four counties of Guangxi, China, with the highest rate found in township hospitals. A significant high proportion of prescriptions containing antibiotics were broad-spectrum, by intravenous infusion or with multiple antibiotics, especially at county hospitals. Urgent attention is needed to address this challenge
Tumor Suppression by RNA from C/EBPβ 3â˛UTR through the Inhibition of Protein Kinase CÎľ Activity
BACKGROUND: Since the end of last century, RNAs from the 3'untranslated region (3'UTR) of several eukaryotic mRNAs have been found to exert tumor suppression activity when introduced into malignant cells independent of their whole mRNAs. In this study, we sought to determine the molecular mechanism of the tumor suppression activity of a short RNA from 3'UTR of C/EBPβ mRÎÎ (C/EBPβ 3'UTR RNA) in human hepatocarcinoma cells SMMC-7721. METHODOLOGY/PRINCIPAL FINDINGS: By using Western blotting, immunocytochemistry, molecular beacon, confocal microscopy, protein kinase inhibitors and in vitro kinase assays, we found that, in the C/EBPβ 3'UTR-transfectant cells of SMMC-7721, the overexpressed C/EBPβ 3'UTR RNA induced reorganization of keratin 18 by binding to this keratin; that the C/EBPβ 3'UTR RNA also reduced phosphorylation and expression of keratin 18; and that the enzyme responsible for phosphorylating keratin 18 is protein kinase CÎľ. We then found that the C/EBPβ 3'UTR RNA directly inhibited the phosphorylating activity of protein kinase CÎľ; and that C/EBPβ 3'UTR RNA specifically bound with the protein kinase CÎľ-keratin 18 conjugate. CONCLUSION/SIGNIFICANCE: Together, these facts suggest that the tumor suppression in SMMC-7721 by C/EBPβ 3'UTR RNA is due to the inhibition of protein kinase CÎľ activity through direct physical interaction between C/EBPβ 3'UTR RNA and protein kinase CÎľ. These facts indicate that the 3'UTR of some eukaryotic mRNAs may function as regulators for genes other than their own
Psoriasis Regression Analysis of MHC Loci Identifies Shared Genetic Variants with Vitiligo
Psoriasis is a common inflammatory skin disease with genetic components of both immune system and the epidermis. PSOR1 locus (6q21) has been strongly associated with psoriasis; however, it is difficult to identify additional independent association due to strong linkage disequilibrium in the MHC region. We performed stepwise regression analyses of more than 3,000 SNPs in the MHC region genotyped using Human 610-Quad (Illumina) in 1,139 cases with psoriasis and 1,132 controls of Han Chinese population to search for additional independent association. With four regression models obtained, two SNPs rs9468925 in HLA-C/HLA-B and rs2858881 in HLA-DQA2 were repeatedly selected in all models, suggesting that multiple loci outside PSOR1 locus were associated with psoriasis. More importantly we find that rs9468925 in HLA-C/HLA-B is associated with both psoriasis and vitiligo, providing first important evidence that two major skin diseases share a common genetic locus in the MHC, and a basis for elucidating the molecular mechanism of skin disorders
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A Search for Dark Higgs Bosons
Recent astrophysical and terrestrial experiments have motivated the proposal
of a dark sector with GeV-scale gauge boson force carriers and new Higgs
bosons. We present a search for a dark Higgs boson using 516 fb-1 of data
collected with the BABAR detector. We do not observe a significant signal and
we set 90% confidence level upper limits on the product of the Standard
Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots
for b/w printin
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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