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M Increase (m + increase)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Hepatitis B viral load predicts survival of HCC patients undergoing systemic chemotherapy,

HEPATOLOGY, Issue 6 2007
Winnie Yeo
HCC is a common cause of morbidity and mortality. For patients who are not candidates for curative surgery, systemic chemotherapy is one of the standard treatments. In parts of China and the Far East, over 80% of HCC patients have chronic HBV infection. In this study, we aimed to assess the relationship between pre-chemotherapy HBV viral load and the survival of HCC patients. HBV infection status was determined prior to chemotherapy in 188 patients, 170 of whom had evidence of HBV chronic infection/exposure (160 hepatitis B surface antigen [HBsAg]-positive, 10 HBsAg-negative/hepatitis B core antibody,positive). Of these, 125 had pretreatment HBV DNA levels determined via real-time PCR. Virological data were analyzed using conventional clinical variables to identify factors that influenced survival. Multivariate analysis revealed that high total bilirubin (P = 0.0016; hazard ratio = 1.040 per 1 ,M increase; 95% CI 1.015,1.065), HCV infection (P = 0.0095; hazard ratio = 6.955; 95% CI 1.606,30.129), and high HBV DNA level (P = 0.0217; hazard ratio = 1.650; 95% CI 1.076,2.531) affected survival significantly. Exploratory analysis revealed that high levels of pretreatment HBV DNA had a significantly higher incidence of severe hepatitis during chemotherapy. Conclusion: For HCC patients with HBV chronic infection/exposure, a high viral load prior to treatment is an adverse factor for survival and may be associated with a higher incidence of severe hepatitis during chemotherapy. Future strategies to improve the prognosis of HCC patients undergoing chemotherapy should consider supportive therapy that incorporates antiviral therapies to reduce HBV viral load. (HEPATOLOGY 2007;45:1382,1389.) [source]

Peristaltic transport and heat transfer of a MHD Newtonian fluid with variable viscosity

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2010
S. Nadeem
Abstract The influence of temperature-dependent viscosity and magnetic field on the peristaltic flow of an incompressible, viscous Newtonian fluid is investigated. The governing equations are derived under the assumptions of long wavelength approximation. A regular perturbation expansion method is used to obtain the analytical solutions for the velocity and temperature fields. The expressions for the pressure rise, friction force and the relation between the flow rate and pressure gradient are obtain. In addition to analytical solutions, numerical results are also computed and compared with the analytical results with good agreement. The results are plotted for different values of variable viscosity parameter ,, Hartmann number M, and amplitude ratio ,. It is found that the pressure rise decreases as the viscosity parameter , increases and it increases as the Hartmann number M increases. Finally, the maximum pressure rise (,=0) increases as M increases and , decreases. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Towards an isotopic ecology of herbivory in the Puna ecosystem: new results and patterns on Lama glama

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 2 2009
H. D. Yacobaccio
Abstract We present stable isotopic data obtained in order to elucidate the diet of current domestic camelids and their feeding areas, as a necessary step for the interpretation of archaelogical assemblages, and to answer questions regarding past diet, herd structure, foraging zones and interaction with human populations. Seventeen new ,13C collagen isotope values from Lama glama bones were measured in order to start a systematic study of the isotopic ecology of herbivory in the Puna ecosystem of Jujuy province, Argentina. These values were compared with those previously available, and a reliable correlation between altitude and variation in isotopic values was found: of the order of ,2, depletion for each 500,m increase in altitude. These results were interpreted as related to variation in vegetal assemblage due to altitude. We consider that the outcomes of this research exceed the scope of our study area, being important to the Argentine Puna as a whole, and will also contribute to the development of current animal population ecological models applied to the interpretation of archaeological remains. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Height-related trends in leaf xylem anatomy and shoot hydraulic characteristics in a tall conifer: safety versus efficiency in water transport

NEW PHYTOLOGIST, Issue 1 2008
D. R. Woodruff
Summary ,,Hydraulic vulnerability of Douglas-fir (Pseudotsuga menziesii) branchlets decreases with height, allowing shoots at greater height to maintain hydraulic conductance (Kshoot) at more negative leaf water potentials (,l). ,,To determine the basis for this trend shoot hydraulic and tracheid anatomical properties of foliage from the tops of Douglas-fir trees were analysed along a height gradient from 5 to 55 m. ,,Values of ,l at which Kshoot was substantially reduced, declined with height by 0.012 Mpa m,1. Maximum Kshoot was reduced by 0.082 mmol m,2 MPa,1 s,1 for every 1 m increase in height. Total tracheid lumen area per needle cross-section, hydraulic mean diameter of leaf tracheid lumens, total number of tracheids per needle cross-section and leaf tracheid length decreased with height by 18.4 µm2 m,1, 0.029 µm m,1, 0.42 m,1 and 5.3 µm m,1, respectively. Tracheid thickness-to-span ratio (tw/b)2 increased with height by 1.04 × 10,3 m,1 and pit number per tracheid decreased with height by 0.07 m,1. ,,Leaf anatomical adjustments that enhanced the ability to cope with vertical gradients of increasing xylem tension were attained at the expense of reduced water transport capacity and efficiency, possibly contributing to height-related decline in growth of Douglas fir. [source]

Analysis of quantum efficiency and optical enhancement in amorphous Si p,i,n solar cells

PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 4 2002
Steven S. Hegedus
The effect of i -layer thickness, tin oxide texture, and back reflector (BR) on optical enhancement has been systematically studied in a series of 20 a-Si p,i,n solar cells. The internal quantum efficiency has been analyzed by a simple model based on the work of Schade and Smith. The enhancement of optical absorption is characterized by m, a wavelength-dependent fitting parameter representing the increase in optical pathlength relative to the i -layer thickness d. Solar cells with an Al BR have negligible optical enhancement, with m,<,1.5, consistent with large parasitic absorption at the Al/Si interface as reported by others. Solar cells on highly textured SnO2 with ZnO/Al or ZnO/Ag BR have peak values of m,,,3,4, with ZnO/Ag having slightly larger values than ZnO/Al. It was found that m has a strong dependence on the product ,d, and that maximum values of m increase with reflectivity of the BR. It is shown that a major source of parasitic absorption loss at long wavelengths is light trapping in the textured SnO2 front contact. Copyright © 2002 John Wiley & Sons, Ltd. [source]