367 research outputs found
Determination and Distribution Study of Pogostone in Rat Tissues by Ultra-Fast Liquid Chromatography
Purpose: To develop and validate a rapid, sensitive and reliable ultra-fast liquid chromatography (UFLC) method with photodiode array (PDA) detection for the determination of pogostone (PO) in rat tissues using honokiol as internal standard (IS).Methods: Rats were randomly divided into two groups (intravenous administration group and oral administration group) and given of a single dose of 10 mg/kg PO by intravenous administration and oral administration, respectively. After intravenous injection, the rats were sacrificed at 15, 60 and 360 min, while rats, after oral administration, were euthanasized at 30, 90 and 360 min, respectively. For the analysis of the preparation, optimal chromatographic conditions were determined using Acquity UPLC BEH C18 column with acetonitrile-water containing 0.1 % formic acid (55:45, v/v) as the mobile phase, at a flow rate of 400 μL/min. UV detection wavelength was set at 310 nm with temperature maintained at 30 °C.Results: Good linear relationship of calibration curve (r > 0.9984) was achieved over the range of 0.1 - 40 μg/mL for all the tissue samples. The limit of quantification (LOQ) and limit of detection (LOD) were 0.1 and 0.05 μg/mL, respectively. This method proved to have good precision, accuracy, stability, extraction recovery and matrix effect for tissue distribution studies of PO in rats.Conclusion: The developed method is suitable for tissue distribution studies in rats following intravenous and oral administration of PO at a dose of 10 mg/kg.Keywords: Ultra-fast liquid chromatography, Tissue distribution, Pogostone, Honokiol, Rat
Systematic Parameterization, Storage, and Representation of Volumetric DICOM Data
Tomographic medical imaging systems produce hundreds to thousands of slices, enabling three-dimensional (3D) analysis. Radiologists process these images through various tools and techniques in order to generate 3D renderings for various applications, such as surgical planning, medical education, and volumetric measurements. To save and store these visualizations, current systems use snapshots or video exporting, which prevents further optimizations and requires the storage of significant additional data. The Grayscale Softcopy Presentation State extension of the Digital Imaging and Communications in Medicine (DICOM) standard resolves this issue for two-dimensional (2D) data by introducing an extensive set of parameters, namely 2D Presentation States (2DPR), that describe how an image should be displayed. 2DPR allows storing these parameters instead of storing parameter applied images, which cause unnecessary duplication of the image data. Since there is currently no corresponding extension for 3D data, in this study, a DICOM-compliant object called 3D presentation states (3DPR) is proposed for the parameterization and storage of 3D medical volumes. To accomplish this, the 3D medical visualization process is divided into four tasks, namely pre-processing, segmentation, post-processing, and rendering. The important parameters of each task are determined. Special focus is given to the compression of segmented data, parameterization of the rendering process, and DICOM-compliant implementation of the 3DPR object. The use of 3DPR was tested in a radiology department on three clinical cases, which require multiple segmentations and visualizations during the workflow of radiologists. The results show that 3DPR can effectively simplify the workload of physicians by directly regenerating 3D renderings without repeating intermediate tasks, increase efficiency by preserving all user interactions, and provide efficient storage as well as transfer of visualized data. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s40846-015-0097-5) contains supplementary material, which is available to authorized users
New insight into kinetics behavor of the structural formation process in Agar gelation
A time-resolved experimental study on the kinetics and relaxation of the
structural formation process in gelling Agar-water solutions was carried out
using our custom-built torsion resonator. The study was based on measurements
of three naturally cooled solutions with agar concentrations of 0.75%, 1.0% and
2.0% w/w. It was found that the natural-cooling agar gelation process could be
divided into three stages, sol stage (Stage I), gelation zone (Stage II) and
gel stage (Stage III), based on the time/temperature evolutions of the
structural development rate (SDR). An interesting fluctuant decaying behavior
of SDR was observed in Stage II and III, indicative of a sum of multiple
relaxation processes and well described by a multiple-order Gaussisn-like
equation: . More interestingly, the temperature dependences of the fitted
values of Wn in Stage II and Stage III were found to follow the different
Arrhenius laws, with different activation energies of EaII= 39-74 KJ/mol and
EaIII~7.0 KJ/mol. The two different Arrhenius-like behaviors respectively
suggest that dispersions in Stage II be attributed to the relaxation of the
self-assembly of agar molecules or the growth of junction zones en route to
gelation, in which the formation or fission of hydrogen bonding interactions
plays an important role; and that dispersions in Stage III be attributed to the
relaxation dynamics of water released from various size domains close to the
domain of the viscous flow of water during the syneresis process.Comment: 24 pages, 4 figures, 1 tabl
Nanogrids and Beehive-Like Nanostructures Formed by Plasma Etching the Self-Organized SiGe Islands
A lithography-free method for fabricating the nanogrids and quasi-beehive nanostructures on Si substrates is developed. It combines sequential treatments of thermal annealing with reactive ion etching (RIE) on SiGe thin films grown on (100)-Si substrates. The SiGe thin films deposited by ultrahigh vacuum chemical vapor deposition form self-assembled nanoislands via the strain-induced surface roughening (Asaro-Tiller-Grinfeld instability) during thermal annealing, which, in turn, serve as patterned sacrifice regions for subsequent RIE process carried out for fabricating nanogrids and beehive-like nanostructures on Si substrates. The scanning electron microscopy and atomic force microscopy observations confirmed that the resultant pattern of the obtained structures can be manipulated by tuning the treatment conditions, suggesting an interesting alternative route of producing self-organized nanostructures
Systemic chemotherapy with doxorubicin, cisplatin and capecitabine for metastatic hepatocellular carcinoma
BACKGROUND: Although numerous chemotherapeutic agents have been tested, the role of systemic chemotherapy for hepatocellular carcinoma (HCC) has not been clarified. New therapeutic strategies are thus needed to improve outcomes, and we designed this study with new effective drug combination. METHODS: Twenty-nine patients with histologically-confirmed, metastatic HCC received a combination chemotherapy with doxorubicin 60 mg/m(2 )and cisplatin 60 mg/m(2 )on day 1, plus capecitabine 2000 mg/m(2)/day as an intermittent regimen of 2 weeks of treatment followed by a 1-week rest. RESULTS: The median age was 49 years (range, 32–64) and 19 patients were hepatitis B virus seropositive. Child-Pugh class was A in all patients and 4 had Zubrod performance status of 2. The objective response rate was 24% (95% CI 9–40) with 6 stable diseases. The chemotherapy was generally well tolerated despite one treatment-related death. CONCLUSION: Combination chemotherapy with doxorubicin, cisplatin and capecitabine produced modest antitumor activity with tolerable adverse effects in patients with metastatic HCC
Direct Measurement of B(D0->phiX0) and B(D+->phiX+)
The first measurement of B(0->phi X0) and an upper limit for B(D+->phi X+)
are determined from 22.3 pb-1 of e+e- annihilation data at a C. M. energy of
4.03 GeV. The data were recorded by the Beijing Spectrometer (BES) at BEPC. A
recoil charge method is applied for the first time to charm threshold data to
determine the charge of the D meson in the recoil from 9054+-309+-416
reconstructed D0, D+ mesons. The branching fractions B(D->phiX0)
=(1.71+0.76-0.71+-0.17)%, and B(D+->phiX+) <1.8% are determined from 10 events
with a reconstructed D and a recoiling phi. In addition, a 90% C.L. upper limit
of B(D+->phi e+X0)<1.6% is determined from a search for semileptonic decays of
the D+.Comment: Submitted to Phys. Rev.
Adolescents' experience of comments about their weight – prevalence, accuracy and effects on weight misperception
<p>Abstract</p> <p>Background</p> <p>Weight comments are commonly received by adolescents, but the accuracy of the comments and their effects on weight misperception are unclear. We assessed the prevalence and accuracy of weight comments received by Chinese adolescents from different sources and their relation to weight misperception.</p> <p>Methods</p> <p>In the Hong Kong Student Obesity Surveillance (HKSOS) project 2006–07, 22612 students aged 11–18 (41.5% boys) completed a questionnaire on obesity. Students responded if family members, peers and professionals had seriously commented over the past 30 days that they were "too fat" or "too thin" in two separate questions. The accuracy of the comments was judged against the actual weight status derived from self-reported height and weight. Self-perceived weight status was also reported and any discordance with the actual weight status denoted weight misperception. Logistic regression yielded adjusted odd ratios for weight misperception by the type of weight comments received.</p> <p>Results</p> <p>One in three students received weight comments, and the mother was the most common source of weight comments. Health professional was the most accurate source of weight comments, yet less than half the comments were correct. Adolescents receiving incorrect comments had increased risk of having weight misperception in all weight status groups. Receiving conflicting comments was positively associated with weight misperception among normal weight adolescents. In contrast, underweight and overweight/obese adolescents receiving correct weight comments were less likely to have weight misperception.</p> <p>Conclusion</p> <p>Weight comments, mostly incorrect, were commonly received by Chinese adolescents in Hong Kong, and such incorrect comments were associated with weight misperception.</p
Deficient NRG1-ERBB signaling alters social approach: relevance to genetic mouse models of schizophrenia
Growth factor Neuregulin 1 (NRG1) plays an essential role in development and organization of the cerebral cortex. NRG1 and its receptors, ERBB3 and ERBB4, have been implicated in genetic susceptibility for schizophrenia. Disease symptoms include asociality and altered social interaction. To investigate the role of NRG1-ERBB signaling in social behavior, mice heterozygous for an Nrg1 null allele (Nrg1+/−), and mice with conditional ablation of Erbb3 or Erbb4 in the central nervous system, were evaluated for sociability and social novelty preference in a three-chambered choice task. Results showed that deficiencies in NRG1 or ERBB3 significantly enhanced sociability. All of the mutant groups demonstrated a lack of social novelty preference, in contrast to their respective wild-type controls. Effects of NRG1, ERBB3, or ERBB4 deficiency on social behavior could not be attributed to general changes in anxiety-like behavior, activity, or loss of olfactory ability. Nrg1+/− pups did not exhibit changes in isolation-induced ultrasonic vocalizations, a measure of emotional reactivity. Overall, these findings provide evidence that social behavior is mediated by NRG1-ERBB signaling
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Search for ψ(2S) production in e+e- annihilations at 4.03 GeV
A search is performed for the production of the (Formula presented) in (Formula presented) annihilation at a center-of-mass energy of 4.03 GeV using the BES detector operated at the Beijing Electron Positron Collider (BEPC). The kinematic features of the reconstructed (Formula presented) signal are consistent with its being produced only in association with an energetic photon resulting from initial state radiation (ISR). Limits are placed on (Formula presented) production from the decay of unknown charmonia or metastable hybrids that might be produced in (Formula presented) annihilations at 4.03 GeV. Under the assumption that the observed cross section for (Formula presented) production is due entirely to ISR, the partial width (Formula presented) of the (Formula presented) is measured to be (Formula presented). © 1998 The American Physical Society
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