224 research outputs found
Measuring Complex Refractive Indices of a Nanometer-Thick Superconducting Film Using Terahertz Time-Domain Spectroscopy with a 10 Femtoseconds Pulse Laser
Superconducting thin films are widely applied in various fields, including switching devices, because of their phase transition behaviors in relation to temperature changes. Therefore, it is important to quantitatively determine the optical constant of a superconducting material in the thin-film state. We performed a terahertz time-domain spectroscopy, based on a 10 femtoseconds pulse laser, to measure the optical constant of a superconducting GdBa2Cu3O7-x (GdBCO) thin film in the terahertz region. We then estimated the terahertz refractive indices of the 70 nm-thick GdBCO film using a numerical extraction process, even though the film thickness was approximately 1/10,000 times smaller than the terahertz wavelength range of 200 mu m to 1 mm. The resulting refractive indices of the GdBCO thin film were consistent with the theoretical results using the two-fluid model. Our work will help to further understand the terahertz optical properties of superconducting thin films with thicknesses under 100 nm, as well as provide a standard platform for characterizing the optical properties of thin films without the need of Kramers-Kronig transformation at the terahertz frequencies
Raman Scattered HeII 6545 in the Young and Compact Planetary Nebula NGC 6790
We present the high resolution spectra of the youn and compact planerary
nebula NGC 6790 obtained with the echelle spectrograph at Bohyunsan Optical
Astronomy Observatory and report the discovery of Raman scattered He II 6545 in
this object. This line feature is formed in a thick neutral region surrounding
the hot central star, where He II 1025 line photons are scattered inelastically
by hydrogen atoms. A Monte Carlo technique is adopted to compute the line
profile with a simple geometric model, in which the neutral region is in the
form of a cylindrical shell that is expanding from the central star. From our
line profile analysis, the expansion velocity of the HI region lies in the
range V_exp = 15- 19 Km/s. Less stringent constraints are put on the HI column
density N_HI and covering factor C, where the total flux of Raman He II 6545 is
consistent with the product of N_HI and C being CN_HI ~ 0.5 X 10^20 cm^-2. The
Monte Carlo profiles from stationary emission models exhibit deficit in the
wing parts. A much better fit is obtained when the He II emission region is
assumed to take the form of a ring that slowly rotates with a rotation speed ~
18Km/s. Brief discussions are presented regarding the mass loss processes and
future observations
Efficacy and safety evaluation of black ginseng (Panax ginseng C.A. Mey.) extract (CJ EnerG): broad spectrum cytotoxic activity in human cancer cell lines and 28-day repeated oral toxicity study in Sprague-Dawley rats
Abstract
Background
Ginseng (Panax ginseng C.A. Mey.) has been used as a valuable ingredient in traditional medicine for thousands of years mostly in Asian countries due to its therapeutic effects in various diseases. Among the processed ginseng products, black ginseng is produced by a repeated steaming and drying process of ginseng roots and has been known for its superior efficacy based on high accumulation of minor ginsenosides as recently discovered. Despite its popularity and increasing use, the toxicity information on black ginseng still remained largely lacking, raising safety concerns. This study was therefore carried out to determine the repeated oral toxicity of black ginseng extract (BGE; CJ EnerG) with evaluation of cytotoxic activity as validation of its pharmacological activity for toxicity testing.
Methods
Prior to the toxicity test, we examined the cytotoxicity of BGE in six cancer cell lines derived from distinct human tissues in comparison with red ginseng extract (RGE), ginsenosides Rg5 and 20(S)-Rg3, and then assessed 28-day repeated oral toxicity in Sprague-Dawley (SD) rats using daily administration of up to 2000 mg/kg BGE.
Results
BGE showed higher cytotoxicity than RGE in all the cell lines used in this study. Interestingly, the efficacy of BGE closely resembled the cytotoxic pattern of Rg5, suggesting Rg5 as the main effector in the cytotoxic activity of BGE. During the toxicity study, BGE-treated groups showed no noticeable abnormality in clinical signs, body weight gain, food and water consumption and urinalysis. Furthermore, hematological, serum biochemical and histopathological analyses did not find any BGE-related toxicity.
Conclusion
Our findings demonstrated that BGE has broad-spectrum in vitro cytotoxic activity, and that NOAEL of BGE in SD rats is > 2000 mg/kg, providing the essential safety information for human consumption
TonEBP suppresses IL-10-mediated immunomodulation
TonEBP is a key transcriptional activator of M1 phenotype in macrophage, and its high expression is associated with many inflammatory diseases. During the progression of the inflammatory responses, the M1 to M2 phenotypic switch enables the dual role of macrophages in controlling the initiation and resolution of inflammation. Here we report that in human and mouse M1 macrophages TonEBP suppresses IL-10 expression and M2 phenotype. TonEBP knockdown promoted the transcription of the IL-10 gene by enhancing chromatin accessibility and Sp1 recruitment to its promoter. The enhanced expression of M2 genes by TonEBP knockdown was abrogated by antagonism of IL-10 by either neutralizing antibodies or siRNA-mediated silencing. In addition, pharmacological suppression of TonEBP leads to similar upregulation of IL-10 and M2 genes. Thus, TonEBP suppresses M2 phenotype via downregulation of the IL-10 in M1 macrophagesope
In vivo and in vitro safety evaluation of fermented Citrus sunki peel extract: acute and 90-day repeated oral toxicity studies with genotoxicity assessment
Abstract
Background
Citrus sunki Hort. ex Tanaka peel has been traditionally used as an ingredient in folk medicine due to its therapeutic effects on promotion of splenic health and diuresis as well as relief of gastrointestinal symptoms. Although a growing interest in health-promoting natural products and the development of highly concentrated products have facilitated consumption of C. sunki peel, its safety assessment has not been explored, posing a potential health risk. In this study, we carried out a series of systemic and genetic toxicity tests on fermented C. sunki peel extract (FCPE) to provide the essential information required for safe use in human.
Methods
We conducted acute and 90-day repeated oral toxicity studies in Sprague-Dawley rats to evaluate systemic toxicity, and three genotoxicity assays to measure bacterial mutation reversion, cellular chromosome aberration and in vivo micronucleus formation.
Results
Single oral administration of FCPE did not cause any clinical signs and lethality in all animals, establishing LD50 to be over 2000 mg/kg BW. Repeated administration of up to 2000 mg/kg BW FCPE for 90 days revealed no test substance-related toxicity as demonstrated in analysis of body weight gain, food/water intake, blood, serum biochemistry, organweight and histopathology, collectively determining that the no-observable-adverse-effect-level of FCPE is over 2000 mg/kg BW. In addition, we detected no mutagenicity and clastogenicity in FCPE at 5000 μg/plate for the in vitro assays and 2000 mg/kg BW for the in vivo micronucleus test.
Conclusion
FCPE did not cause systemic and genetic toxicity in our model systems at the tested dose levels. These results suggest a guideline for safe consumption of C. sunki peel in human
Acute Kidney Injury due to Menstruation-related Disseminated Intravascular Coagulation in an Adenomyosis Patient: A Case Report
The authors report a case of acute kidney injury (AKI) resulting from menstruation-related disseminated intravascular coagulation (DIC) in an adenomyosis patient. A 40-yr-old woman who had received gonadotropin for ovulation induction therapy presented with anuria and an elevated serum creatinine level. Her medical history showed primary infertility with diffuse adenomyosis. On admission, her pregnancy test was negative and her menstrual cycle had started 1 day previously. Laboratory data were consistent with DIC, and it was believed to be related to myometrial injury resulting from heavy intramyometrial menstrual flow. Gonadotropin is considered to play an important role in the development of fulminant DIC. This rare case suggests that physicians should be aware that gonadotropin may provoke fulminant DIC in women with adenomyosis
CRISPR/Cas9-induced knockout and knock-in mutations in Chlamydomonas reinhardtii
Genome editing is crucial for genetic engineering of organisms for improved traits, particularly in microalgae due to the urgent necessity for the next generation biofuel production. The most advanced CRISPR/Cas9 system is simple, efficient and accurate in some organisms; however, it has proven extremely difficult in microalgae including the model alga Chlamydomonas. We solved this problem by delivering Cas9 ribonucleoproteins (RNPs) comprising the Cas9 protein and sgRNAs to avoid cytotoxicity and off-targeting associated with vector-driven expression of Cas9. We obtained CRISPR/Cas9-induced mutations at three loci including MAA7, CpSRP43 and ChlM, and targeted mutagenic efficiency was improved up to 100 fold compared to the first report of transgenic Cas9-induced mutagenesis. Interestingly, we found that unrelated vectors used for the selection purpose were predominantly integrated at the Cas9 cut site, indicative of NHEJ-mediated knock-in events. As expected with Cas9 RNPs, no off-targeting was found in one of the mutagenic screens. In conclusion, we improved the knockout efficiency by using Cas9 RNPs, which opens great opportunities not only for biological research but also industrial applications in Chlamydomonas and other microalgae. Findings of the NHEJ-mediated knock-in events will allow applications of the CRISPR/Cas9 system in microalgae, including safe harboring techniques shown in other organisms.
CRISPR/Cas9-induced knockout and knock-in mutations in Chlamydomonas reinhardtii
Genome editing is crucial for genetic engineering of organisms for improved traits, particularly in microalgae due to the urgent necessity for the next generation biofuel production. The most advanced CRISPR/Cas9 system is simple, efficient and accurate in some organisms; however, it has proven extremely difficult in microalgae including the model alga Chlamydomonas. We solved this problem by delivering Cas9 ribonucleoproteins (RNPs) comprising the Cas9 protein and sgRNAs to avoid cytotoxicity and off-targeting associated with vector-driven expression of Cas9. We obtained CRISPR/Cas9-induced mutations at three loci including MAA7, CpSRP43 and ChlM, and targeted mutagenic efficiency was improved up to 100 fold compared to the first report of transgenic Cas9-induced mutagenesis. Interestingly, we found that unrelated vectors used for the selection purpose were predominantly integrated at the Cas9 cut site, indicative of NHEJ-mediated knock-in events. As expected with Cas9 RNPs, no off-targeting was found in one of the mutagenic screens. In conclusion, we improved the knockout efficiency by using Cas9 RNPs, which opens great opportunities not only for biological research but also industrial applications in Chlamydomonas and other microalgae. Findings of the NHEJ-mediated knock-in events will allow applications of the CRISPR/Cas9 system in microalgae, including "safe harboring" techniques shown in other organisms142561sciescopu
Pulmonary Complications After Hematopoietic Stem Cell Transplantation
Despite advanced effective prophylaxes, pulmonary complications still occur in a high proportion of all hematopoietic stem cell recipients, accounting for considerable morbidity and mortality. The aim of our study was to describe the causes, incidences and mortality rates secondary to pulmonary complications and risk factors of such complications following hematopoietic stem cell transplantation (HSCT). We reviewed the medical records of 287 patients who underwent either autologous or allogeneic HSCT for hematologic disorders from February 1996 to October 2003 at Samsung Medical Center (134 autografts, 153 allografts). The timing of pulmonary complications was divided into pre-engraftment, early and late period. The spectrum of pulmonary complications included infectious and non-infectious conditions. 73 of the 287 patients (25.4%) developed pulmonary complications. Among these patients, 40 (54.8%) and 29 (39.7%) had infectious and non-infectious conditions, respectively. The overall mortality rate from pulmonary complications was 28.8%. Allogeneic transplant, grade II-IV acute graft-versus-host disease (GVHD) and extensive chronic GVHD were the risk factors with statistical significance for pulmonary complications after HSCT. The mortality rates from pulmonary complications following HSCT were high, especially those of viral and fungal pneumonia, diffuse alveolar hemorrhage and idiopathic pneumonia syndrome
Tonicity-responsive enhancer-binding protein promotes hepatocellular carcinogenesis, recurrence and metastasis
Objectives: Hepatocellular carcinoma (HCC) is a common cancer with high rate of recurrence and mortality. Diverse aetiological agents and wide heterogeneity in individual tumours impede effective and personalised treatment. Tonicity-responsive enhancer-binding protein (TonEBP) is a transcriptional cofactor for the expression of proinflammatory genes. Although inflammation is intimately associated with the pathogenesis of HCC, the role of TonEBP is unknown. We aimed to identify function of TonEBP in HCC.
Design: Tumours with surrounding hepatic tissues were obtained from 296 patients with HCC who received completion resection. TonEBP expression was analysed by quantitative reverse transcription-quantitative real-time PCR (RT-PCR) and immunohfistochemical analyses of tissue microarrays. Mice with TonEBP haplodeficiency, and hepatocyte-specific and myeloid-specific TonEBP deletion were used along with HCC and hepatocyte cell lines.
Results: TonEBP expression is higher in tumours than in adjacent non-tumour tissues in 92.6% of patients with HCC regardless of aetiology associated. The TonEBP expression in tumours and adjacent non-tumour tissues predicts recurrence, metastasis and death in multivariate analyses. TonEBP drives the expression of cyclo-oxygenase-2 (COX-2) by stimulating the promoter. In mouse models of HCC, three common sites of TonEBP action in response to diverse aetiological agents leading to tumourigenesis and tumour growth were found: cell injury and inflammation, induction by oxidative stress and stimulation of the COX-2 promoter.
Conclusions: TonEBP is a key component of the common pathway in tumourigenesis and tumour progression of HCC in response to diverse aetiological insults. TonEBP is involved in multiple steps along the pathway, rendering it an attractive therapeutic target as well as a prognostic biomarker
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