1,241 research outputs found
Powerful Actuation of Magnetized Microtool by Focused Magnetic Field on a Disposable Microfluidic Chip
Anti – inflammatory and antioxidant effects of Tetrapleura Tetraptera (Schumach & Thonn.) taub. fruit extract in Carrageenan/Kaolin-induced acute monoarthritis in rats
Background: Tetrapleura tetraptera has been reported traditionally for the treatments of various ailments, which include convulsion, leprosy, inflammation and rheumatic pains, schistosomiasis, asthma and hypertension. The antiinflammatory activity of the aqueous extract of T. tetraptera fruit in egg albumin-induced paw oedema as well as in vitro anti-inflammatory and antioxidant activity had been documented. However, there had been no studies on the antiarthritic properties of the plant.Objectives: The present study was designed to investigate in vivo anti-inflammatory and anti-oxidant activities of the methanol extract Tetrapleura tetraptera in carrageenan/kaolin-induced acute monoarthritis in rat.Materials and methods: The acute toxicity of the methanol plant extract was determined using Lorke’s method. In vivo carrageenan/kaolin induced arthritis assay was performed on Tetrapleura tetraptera (TtME) extract (100, 200 and 400 mg/kg) using albino rats. Indomethacin (10 mg/kg) and normal saline were employed as positive and negative controls, respectively. Histological study was performed on the knee joint of the animals after collection of blood for antioxidants analysis.Results: Acute toxicity study showed that TtME is safe by oral administration up to 5000 mg/kg body weight. Oral administration of TtME and indomethacin (10 mg/kg) produced a significant (p < 0.05) time and dose-dependent decrease in joint diameter. There was a decrease in malondialdehyde and increase in glutathione and superoxide dismutase. The histological assessment revealed no major adverse effects on the animals.Conclusion: Tetrapleura tetraptera fruit extract possesses anti-arthritic activity, which may be attributed to its antiinflammatory and antioxidant activity.Keywords: Tetrapleura tetraptera, Antioxidant, Anti-inflammatory, Anti-arthritic activity, Histopatholog
WIDGET: System Performance and GRB Prompt Optical Observations
The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for
a fully automated, ultra-wide-field survey aimed at detecting the prompt
optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the
HETE-2 and Swift/BAT pointing directions covering a total field of view of 62
degree x 62 degree every 10 secounds using an unfiltered system. This
monitoring survey allows exploration of the optical emission before the
gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r'
system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten
simultaneous and one pre-trigger GRB observations. The efficiency of
synchronized observation with HETE-2 is four times better than that of Swift.
There has been no bright optical emission similar to that from GRB 080319B. The
statistical analysis implies that GRB080319B is a rare event. This paper
summarizes the design and operation of the WIDGET system and the simultaneous
GRB observations obtained with this instrument.Comment: 19 pages, 11 figures, Accepted to appear in PAS
Spectral Cross-calibration of the Konus-Wind, the Suzaku/WAM, and the Swift/BAT Data using Gamma-Ray Bursts
We report on the spectral cross-calibration results of the Konus-Wind, the
Suzaku/WAM, and the Swift/BAT instruments using simultaneously observed
gamma-ray bursts (GRBs). This is the first attempt to use simultaneously
observed GRBs as a spectral calibration source to understand systematic
problems among the instruments. Based on these joint spectral fits, we find
that 1) although a constant factor (a normalization factor) agrees within 20%
among the instruments, the BAT constant factor shows a systematically smaller
value by 10-20% compared to that of Konus-Wind, 2) there is a systematic trend
that the low-energy photon index becomes steeper by 0.1-0.2 and Epeak becomes
systematically higher by 10-20% when including the BAT data in the joint fits,
and 3) the high-energy photon index agrees within 0.2 among the instruments.
Our results show that cross-calibration based on joint spectral analysis is an
important step to understanding the instrumental effects which could be
affecting the scientific results from the GRB prompt emission data.Comment: 82 pages, 88 figures, accepted for publication in PAS
Spectral Evolutions in Gamma-Ray Burst Exponential Decays Observed with Suzaku WAM
This paper presents a study on the spectral evolution of gamma-ray burst
(GRB) prompt emissions observed with the Suzaku Wide-band All-sky Monitor
(WAM). By making use of the WAM data archive, 6 bright GRBs exhibiting 7
well-separated fast-rise-exponential-decay (FRED) shaped light curves are
presented and the evaluated exponential decay time constants of the
energy-resolved light curves from these FRED peak light curves are shown to
indicate significant spectral evolution. The energy dependence of the time
constants is well described with a power-law function tau(E) ~ E^gamma, where
gamma ~ -(0.34 +/- 0.12) in average, although 5 FRED peaks show consistent
value of gamma = -1/2 which is expected in synchrotron or inverse-Compton
cooling models. In particular, 2 of the GRBs were located with accuracy
sufficient to evaluate the time-resolved spectra with precise energy response
matrices. Their behavior in spectral evolution suggests two different origins
of emissions. In the case of GRB081224, the derived 1-s time-resolved spectra
are well described by a blackbody radiation model with a power-law component.
The derived behavior of cooling is consistent with that expected from radiative
cooling or expansion of the emission region. On the other hand, the other 1-s
time-resolved spectra from GRB100707A is well described by a Band GRB model as
well as with the thermal model. Although relative poor statistics prevent us to
conclude, the energy dependence in decaying light curve is consistent with that
expected in the former emission mechanism model.Comment: 11 pages, 7 figures, 5 tables. PASJ accepte
Low energy effective action on a self-gravitating D-brane
Recently the study of braneworld on the self-gravitating D-brane has been
initiated and derived the gravitational equation on the brane by holographic
and geometrical projection methods. Surprisingly, in common with these two
methods, the matter on the brane cannot be the source of the gravity on the
brane at leading order. In this paper we will propose the low energy effective
action on the D-brane coupled with gravity which derives the same results.Comment: 8 pages, minor corrections, accepted for publication in Physical
Review
Photochemical Processes in a Rhenium(I) Tricarbonyl N-Heterocyclic Carbene Complex Studied by Time-Resolved Measurements
We carried out time-resolved infrared (TR-IR) and emission lifetime measurements on a Re(I) carbonyl complex having an N-heterocyclic carbene ligand, namely, fac-[Re(CO)3(PyImPh)Br], under photochemically reactive (in solution in acetonitrile) and nonreactive (in solution in dichloromethane) conditions to investigate the mechanism of photochemical ligand substitution reactions. The TR-IR measurements revealed that no reaction occurs on a picosecond time scale and the cationic product, namely, fac-[Re(CO)3(PyImPh)(MeCN)](+), is produced on a nanosecond time scale only in solution in acetonitrile, which indicates that the reaction proceeds thermally from the excited state. Because no other products were observed by TR-IR, we concluded that this cationic product is an intermediate species for further reactions. The measurements of the temperature-dependent emission lifetime and analysis using transition-state theory revealed that the photochemical substitution reaction proceeds from a metal-to-ligand charge transfer excited state, the structure of which allows the potential coordination of a solvent molecule. Thus, the coordinating capacity of the solvent determines whether the reaction proceeds or not. This mechanism is different from those of photochemical reactions of other types of Re(I) carbonyl complexes owing to the unique characteristics of the carbene ligand
Down-regulation of transcription elogation factor A (SII) like 4 (TCEAL4) in anaplastic thyroid cancer
BACKGROUND: Anaplastic thyroid cancer (ATC) is one of the most aggressive human malignancies and appears to arise mainly from transformation of pre-existing differentiated thyroid cancer (DTC). However, the carcinogenic mechanism of anaplastic transformation remains unclear. Previously, we investigated specific genes related to ATC based on gene expression profiling using cDNA microarray analysis. One of these genes, transcription elongation factor A (SII)-like 4 (TCEAL4), encodes a member of the transcription elongation factor A (SII)-like gene family. The detailed function of TCEAL4 has not been described nor has any association between this gene and human cancers been reported previously. METHODS: To investigate the role of TCEAL4 in ATC carcinogenesis, we examined expression levels of TCEAL4 in ACLs as well as in other types of thyroid cancers and normal human tissue. RESULTS: Expression of TCEAL4 was down-regulated in all 11 ACLs as compared to either normal thyroid tissues or papillary and follicular thyroid cancerous tissues. TCEAL4 was expressed ubiquitously in all normal human tissues tested. CONCLUSION: To our knowledge, this is the first report of altered TCEAL4 expression in human cancers. We suggest that loss of TCEAL4 expression might be associated with development of ATC from DTC. Further functional studies are required
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