544 research outputs found
Facile synthesis of nano-Li4 Ti5O12 for high-rate Li-ion battery anodes
One of the most promising anode materials for Li-ion batteries, Li4Ti5O12, has attracted attention because it is a zero-strain Li insertion host having a stable insertion potential. In this study, we suggest two different synthetic processes to prepare Li4Ti5O12 using anatase TiO2 nanoprecursors. TiO2 powders, which have extraordinarily large surface areas of more than 250 m2 g-1, were initially prepared through the urea-forced hydrolysis/precipitation route below 100°C. For the synthesis of Li4Ti5O12, LiOH and Li2CO3 were added to TiO2 solutions prepared in water and ethanol media, respectively. The powders were subsequently dried and calcined at various temperatures. The phase and morphological transitions from TiO2 to Li4Ti5O12 were characterized using X-ray powder diffraction and transmission electron microscopy. The electrochemical performance of nanosized Li4Ti5O12 was evaluated in detail by cyclic voltammetry and galvanostatic cycling. Furthermore, the high-rate performance and long-term cycle stability of Li4Ti5O12 anodes for use in Li-ion batteries were discussed
Comparative proteomic analysis of early salt stress-responsive proteins in roots of SnRK2 transgenic rice
<p>Abstract</p> <p>Background</p> <p>The rice roots are highly salt-sensitive organ and primary root growth is rapidly suppressed by salt stress. Sucrose nonfermenting 1-related protein kinase2 (SnRK2) family is one of the key regulator of hyper-osmotic stress signalling in various plant cells. To understand early salt response of rice roots and identify SnRK2 signaling components, proteome changes of transgenic rice roots over-expressing OSRK1, a rice SnRK2 kinase were investigated.</p> <p>Results</p> <p>Proteomes were analyzed by two-dimensional electrophoresis and protein spots were identified by LC-MS/MS from wild type and OSRK1 transgenic rice roots exposed to 150 mM NaCl for either 3 h or 7 h. Fifty two early salt -responsive protein spots were identified from wild type rice roots. The major up-regulated proteins were enzymes related to energy regulation, amino acid metabolism, methylglyoxal detoxification, redox regulation and protein turnover. It is noted that enzymes known to be involved in GA-induced root growth such as fructose bisphosphate aldolase and methylmalonate semialdehyde dehydrogenase were clearly down-regulated. In contrast to wild type rice roots, only a few proteins were changed by salt stress in OSRK1 transgenic rice roots. A comparative quantitative analysis of the proteome level indicated that forty three early salt-responsive proteins were magnified in transgenic rice roots at unstressed condition. These proteins contain single or multiple potential SnRK2 recognition motives. In vitro kinase assay revealed that one of the identified proteome, calreticulin is a good substrate of OSRK1.</p> <p>Conclusions</p> <p>Our present data implicate that rice roots rapidly changed broad spectrum of energy metabolism upon challenging salt stress, and suppression of GA signaling by salt stress may be responsible for the rapid arrest of root growth and development. The broad spectrum of functional categories of proteins affected by over-expression of OSRK1 indicates that OSRK1 is an upstream regulator of stress signaling in rice roots. Enzymes involved in glycolysis, branched amino acid catabolism, dnaK-type molecular chaperone, calcium binding protein, Sal T and glyoxalase are potential targets of OSRK1 in rice roots under salt stress that need to be further investigated.</p
Effects of Infrared Radiation and Heat on Human Skin Aging in vivo
Sunlight damages human skin, resulting in a wrinkled appearance. Since natural sunlight is polychromatic, its ultimate effects on the human skin are the result of not only the action of each wavelength separately, but also interactions among the many wavelengths, including UV, visible light, and infrared (IR). In direct sunlight, the temperature of human skin rises to about 40°C following the conversion of absorbed IR into heat. So far, our knowledge of the effects of IR radiation or heat on skin aging is limited. Recent work demonstrates that IR and heat exposure each induces cutaneous angiogenesis and inflammatory cellular infiltration, disrupts the dermal extracellular matrix by inducing matrix metalloproteinases, and alters dermal structural proteins, thereby adding to premature skin aging. This review provides a summary of current research on the effects of IR radiation and heat on aging in human skin in vivo
Modulation of Skin Collagen Metabolism in Aged and Photoaged Human Skin In Vivo
To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen α1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin
Seroprevalence of Tissue Invading Parasitic Infections Diagnosed by ELISA in Korea
Seroprevalence of the IgG antibodies for Clonorchis sinensis, Paragonimus westermani, Taenia solium metacestode (cysticercus), and Spirometra erinacei plerocercoid (sparganum) was measured using enzyme-linked immunosorbent assay (ELISA) in sera of patients in Korea from 1993 to 2006. A total of 74,448 specimens referred nationwide from 121 hospitals revealed an IgG positive rate of 7.6% for the 4 parasites. The IgG positive rate (18.7%) for the 4 parasites in 1993 decreased gradually to 6.6% in 2006. Individual positive rate decreased from 5.2% (1993) to 1.6% (2006) for C. sinensis, from 2.8% (1993) to 1.1% (2006) for P. westermani, from 8.3% (1993) to 2.2% (2006) for cysticercus, and from 2.6% (1993) to 1.6% (2006) for sparganum. The positive rate was highest (21.2%) in the group of patients who ranged in age from 50-59 yr old, and in the group that was referred from the Seoul area (55.9%). In conclusion, our results suggest that tissue invading parasitic infections should always be included in differential diagnosis for patients with eosinophilia associated lesions of the central nervous system, liver, and lungs in Korea
Case Report Squamous cell carcinoma of the small bowel manifesting as a jejunal perforation: a case report
Abstract: Squamous cell carcinoma arising from the small intestine is rare and difficult to identify as a primary or metastatic feature. We report a case of small intestinal squamous cell carcinoma manifesting as subacute peritonitis due to perforation. An 80-year-old man was admitted to our hospital with intermittent postprandial abdominal pain. He was diagnosed with acute peritonitis due to gastrointestinal perforation. During explorative laparotomy, a perforation site was detected in the jejunum and segmental resection to correct the perforation was performed including the perforation site located at the 70 cm inside the jejunum from the Treitz ligament. The pathology results revealed squamous cell carcinoma in the resected segment of the jejunum with two perforation sites
Outcome prediction of pediatric drowning
Purpose Despite the well-known mortality of pediatric drowning, there is a paucity of evidence on the implications of an initial evaluation on the relevant outcome of drowning. This study aimed to investigate the association of initial clinical findings with outcome of children undergoing drowning. Methods This retrospective study was conducted using the medical records of 56 children undergoing drowning who visited 3 Korean academic hospitals from January 2000 through May 2020. We analyzed information regarding the prehospital resuscitation, drowning time, a 4-tiered chest radiographic grade, and the baseline characteristics. The grade was defined based on the findings of initial chest radiographs. The poor outcomes were defined as the need for intensive care unit care or death aftercare. We analyzed the association of the prehospital resuscitation, submersion time, and the radiographic grade with the poor outcomes using binary logistic regression. Results Among the 56 children, 31 (55.4%) were aged 1-4 years. Prehospital resuscitation and 1-5 minutes of submersion time were noted in the 25 (44.6%) and 30 children (53.6%), respectively. The chest radiographic grades 1 through 4 accounted for 17 (30.4%), 20 (35.7%), 12 (21.4%), and 3 children (5.4%), respectively. Poor outcomes occurred in 17 children (30.4%), including 3 deaths (5.4%). The association with the poor outcomes was noted in the submersion time of longer than 5 minutes (adjusted odds ratio, 21.49; 95% confidence interval, 1.11-415.73; compared with < 1 minute) while not in the submersion time and chest radiographic grade. Conclusion This study confirms that submersion time is an outcome predictor of drowning
Heterogeneous nuclear ribonucleoprotein A1 post-transcriptionally regulates Drp1 expression in neuroblastoma cells.
Excessive mitochondrial fission is associated with the pathogenesis of neurodegenerative diseases. Dynamin-related protein 1 (Drp1) possesses specific fission activity in the mitochondria and peroxisomes. Various post-translational modifications of Drp1 are known to modulate complex mitochondrial dynamics. However, the post-transcriptional regulation of Drp1 remains poorly understood. Here, we show that the heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) regulates Drp1 expression at the post-transcriptional level. hnRNP A1 directly interacts with Drp1 mRNA at its 3'UTR region, and enhances translation potential without affecting mRNA stability. Down-regulation of hnRNP A1 induces mitochondrial elongation by reducing Drp1 expression. Moreover, depletion of hnRNP A1 suppresses 3-NP-mediated mitochondrial fission and dysfunction. In contrast, over-expression of hnRNP A1 promotes mitochondrial fragmentation by increasing Drp1 expression. Additionally, hnRNP A1 significantly exacerbates 3-NP-induced mitochondrial dysfunction and cell death in neuroblastoma cells. Interestingly, treatment with 3-NP induces subcellular translocation of hnRNP A1 from the nucleus to the cytoplasm, which accelerates the increase in Drp1 expression in hnRNP A1 over-expressing cells. Collectively, our findings suggest that hnRNP A1 controls mitochondrial dynamics by post-transcriptional regulation of Drp1.This research was supported by a grant of the Korea–UK Collaborative Alzheimer's Disease Research Project by Ministry of Health & Welfare, Republic of Korea (A120196, HI14C1913) and was supported by the Basic Science Research Program of the National Research Foundation, Republic of Korea (2014R1A2A1A11053431). We are grateful to Wellcome Trust, Principal Research Fellowship to DCR (095317/Z/11/Z)This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.bbagrm.2015.10.01
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