6,188 research outputs found

    Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements

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    The thermal conductivity k of the iron-arsenide superconductor LiFeAs (Tc ~ 18K) was measured in single crystals at temperatures down to T~50mK and in magnetic fields up to H=17T, very close to the upper critical field Hc2~18T. For both directions of the heat current, parallel and perpendicular to the tetragonal c-axis, a negligible residual linear term k/T is found as T ->0, revealing that there are no zero-energy quasiparticles in the superconducting state. The increase in k with magnetic field is the same for both current directions and it follows closely the dependence expected for an isotropic superconducting gap. There is no evidence of multi-band character, whereby the gap would be different on different Fermi-surface sheets. These findings show that the superconducting gap in LiFeAs is isotropic in 3D, without nodes or deep minima anywhere on the Fermi surface. Comparison with other iron-pnictide superconductors suggests that a nodeless isotropic gap is a common feature at optimal doping (maximal Tc).Comment: 4 pages, 3 figure

    Toxicological Study on MUNOPHIL, Water Extract of Panax ginseng and Hericium erinaceum in Rats

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    AbstractObjectiveAs data on the safety profile of Panax ginseng and Hericium erinaceum is lacking, the safety of these two compounds was examined in a series of toxicological studies.Materials and MethodsMUNOPHIL, the water extract mixture of Panax ginseng and Hericium erinaceum was tested in an oral subchronic 28-day toxicity study in rats at doses of 1250, 2500 and 5000 mg/kg/day.ResultsIn repeated dose toxicity studies, no mortality was observed when varying doses of the extracts were administered once daily for a period of 28 days. There were no significant differences in body weight, absolute and relative organ weights between controls and treated rats of both sexes. Hematological analysis showed no differences in most parameters examined. In the biochemistry parameter analysis, no significant change occurred. Pathologically, neither gross abnormalities nor his-topathological changes were observed. Therefore, MUNOPHIL appears to be safe and non-toxic in these studies and a no-observed adverse effect level in rats was established at 5000 mg/kg/day.ConclusionThe data could provide satisfactory preclinical evidence of safety to launch clinical trials on standardized formulation of plant extracts

    Titanium dioxide induces apoptotic cell death through reactive oxygen species-mediated Fas upregulation and Bax activation

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    Background: Titanium dioxide (TiO2) has been widely used in many areas, including biomedicine, cosmetics, and environmental engineering. Recently, it has become evident that some TiO2 particles have a considerable cytotoxic effect in normal human cells. However, the molecular basis for the cytotoxicity of TiO2 has yet to be defined.Methods and results: In this study, we demonstrated that combined treatment with TiO2 nanoparticles sized less than 100 nm and ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-dependent upregulation of Fas and conformational activation of Bax in normal human cells. Treatment with P25 TiO2 nanoparticles with a hydrodynamic size distribution centered around 70 nm (TiO2P25-70) together with ultraviolet A irradiation-induced caspase-dependent apoptotic cell death, accompanied by transcriptional upregulation of the death receptor, Fas, and conformational activation of Bax. In line with these results, knockdown of either Fas or Bax with specific siRNA significantly inhibited TiO2-induced apoptotic cell death. Moreover, inhibition of reactive oxygen species with an antioxidant, N-acetyl-L-cysteine, clearly suppressed upregulation of Fas, conformational activation of Bax, and subsequent apoptotic cell death in response to combination treatment using TiO2P25-70 and ultraviolet A irradiation.Conclusion: These results indicate that sub-100 nm sized TiO2 treatment under ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-mediated upregulation of the death receptor, Fas, and activation of the preapoptotic protein, Bax. Elucidating the molecular mechanisms by which nanosized particles induce activation of cell death signaling pathways would be critical for the development of prevention strategies to minimize the cytotoxicity of nanomaterials.This work was supported by the Korea Ministry of Environment and The Eco-Technopia 21 Project (091-091-081)

    A Highly Sensitive Enzyme-Amplified Immunosensor Based on a Nanoporous Niobium Oxide (Nb2O5) Electrode

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    We report on the development of an enzyme-amplified sandwich-type immunosensor based on a thin gold film sputtered on an anodic nanoporous niobium oxide (Au@Nb2O5) electrode. The electrocatalytic activity of enzymatically amplified electroactive species and a stable electrode consisting of Au@Nb2O5 were used to obtain a powerful signal amplification of the electrochemical immunobiosensor. The method using this electrochemical biosensor based on an Au@Nb2O5 electrode provides a much better performance than those based on conventional bulk gold or niobium oxide electrodes. Our novel approach does not require any time-consuming cleaning steps to yield reproducible electrochemical signals. In addition, the strong adhesion of gold films on the niobium oxide electrodes offers a very stable substrate during electrochemical biosensing. Cyclic voltammetry measurements indicate that non-specific binding of proteins to the modified Au@Nb2O5 surface is sufficiently low to be ignored in the case of our novel system. Finally, we demonstrated the ability of the biosensor based on an Au@Nb2O5 offering the enhanced performance with a high resolution and sensitivity. Therefore, it is expected that the biosensor based on an Au@Nb2O5 has great potential for highly efficient biological devices

    Long-Term Glycaemic Durability of Early Combination Therapy Strategy versus Metformin Monotherapy in Korean Patients with Newly Diagnosed Type 2 Diabetes Mellitus

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    We assessed the glycaemic durability with early combination (EC; vildagliptin+metformin [MET], n=22) versus MET monotherapy (n=17), among newly-diagnosed type 2 diabetes mellitus (T2DM) enrolled (between 2012 and 2014) in the VERIFY study from Korea (n=39). Primary endpoint was time to initial treatment failure (TF) (glycosylated hemoglobin [HbA1c]>= 7.0% at two consecutive scheduled visits after randomization [end of period 1]). Time to second TF was assessed when both groups were receiving and failing on the combination (end of period 2). With EC the risk of initial TF significantly reduced by 78% compared to MET (n=3 [15%] vs. n=10 [58.7%], P=0.0228). No secondary TF occurred in EC group versus five patients (29.4%) in MET. Patients receiving EC treatment achieved consistently lower HbA1c levels. Both treatment approaches were well tolerated with no hypoglycaemic events. In Korean patients with newly diagnosed T2DM, EC treatment significantly and consistently improved the long-term glycaemic durability as compared with MET.Peer reviewe

    Generalized Pustular Psoriasis and Hepatic Dysfunction Associated with Oral Terbinafine Therapy

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    We report a case of 61-yr-old man with stable psoriasis who progressively developed generalized pustular eruption, erythroderma, fever, and hepatic dysfunction following oral terbinafine. Skin biopsy was compatible with pustular psoriasis. After discontinuation of terbinafine and initiating topical corticosteroid and calcipotriol combination with narrow band ultraviolet B therapy, patient'S condition slowly improved until complete remission was reached 2 weeks later. The diagnosis of generalized pustular psoriasis (GPP) induced by oral terbinafine was made. To our knowledge, this is the first report of GPP accompanied by hepatic dysfunction associated with oral terbinafine therapy

    THE ANTERIOR CRUCIATE LIGAMENT INURY PREVENTION PROGRAM: A META-ANALYSIS

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    The purpose of this study was to evaluate the effect of a neuromuscular protocol on the prevention of anterior cruciate ligament (ACL) injury by performing meta-analysis. An extensive literature review was conducted to identify relevant studies, and eventually, only seven randomized controlled trials or prospective cohort studies were included in the analysis. Subgroup analysis revealed that an age under 18, soccer rather than handball, pre- and in-season training rather than either pre or in-season training, and the plyometrics and strengthening components rather than balancing were significant. Metaanalysis showed that pre- and in-season neuromuscular training with an emphasis on plyometrics and strengthening exercises was effective at preventing ACL injury in female athletes, especially in those under 18 years of age

    Prostate Cancer with Solitary Metastases to the Bilateral Testis

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    We present the case of an 81-year-old patient with testicular metastasis from prostate carcinoma. After the initial diagnosis of prostate cancer, he had an 8-year course of hormonal therapy and showed no clinical evidence of metastasis to other organs. Asymptomatic metastasis of prostate carcinoma to the testis is a rare clinical condition. We diagnosed his condition, based on histopathology following a subcapsular orchiectomy and transurethral resection of the prostate

    Decision tree-based approach for online management of PEM fuel cells for residential application

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    This thesis demonstrates a new intelligent technique for the online optimal management of PEM fuel cells units for onsite energy production to supply residential utilizations. Classical optimization techniques are based on offline calculations and cannot provide the necessary computational speed for online performance. In this research, a Decision Tree (DT) algorithm is employed to obtain the optimal, or quasioptimal, settings of the fuel cell online and in a general framework. The main idea is to employ a classification technique, trained on a sufficient subset of data, to produce an estimate of the optimal setting without repeating the optimization process. A database is extracted from a previously-performed Genetic Algorithm (GA)-based optimization has been used to create a suitable decision tree, which was intended for generalizing the optimization results. The approach provides the flexibility of adjusting the settings of the fuel cell online according to the observed variations in the tariffs and load demands. Results at different operating conditions are presented to confirm the high accuracy of the proposed generalization technique. The accuracy of the decision tree has been tested by evaluating the relative error with respect to the optimized values. Then, the possibility of pruning the tree has been investigated in order to simplify its structure without affecting the accuracy of the results. In addition, the accuracy of the DTs to approximate the optimal performance of the fuel cell is compared to that of the Artificial Neural Networks (ANNs) used for the same purpose. The results show that the DTs can somewhat outperform the ANNs with certain pruning levels
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