Lactate dehydrogenase isozyme 5 from rabbit skeletal muscle is activated by citrate, cis-aconitate, isocitrate, alpha-ketoglutarate, succinate, fumarate, malate, aspartate, and glutamate. In the presence of these activators the shape of the pyruvate saturation curve is changed from sigmoid to hyperbolic. Lactate dehydrogenase isozyme 1 from rabbit heart gives a hyperbolic pyruvate saturation cu...

BACKGROUND The aim of this study was to assess the sigmoid line of elasticity in the human aorta. METHODS AND RESULTS The pressure-diameter relation was measured in the descending aorta in 120 subjects. In an additional group of 6 subjects, transient vena caval occlusion produced 5 sets of pressure-diameter data. We found that the best fit curve of the pooled pressure-diameter data was a thir...

Starting instead from a symmetric-antisymmetric reformulation we first show SSIM to be a contrast or visibility function in the classic sense. Furthermore, the previously enigmatic structural covariance is revealed to be the difference of variances. The second step, eliminating the intrinsic quadratic nature of SSIM, allows a near linear correlation with human observer scores, and without invok...

background : colorectal cancer is the most common cancer and the second leading cause of cancer deaths. annually it is the cause of more than 500000 deaths worldwide. therefore, detection and treatment of these tumors could potentially enhance recovery and improve prognosis. this study determines the frequency of colorectal tumors among patients who underwent colonoscopies in imam khomeini hosp...

in this article, the prcsigrnoid avenue to pertroclivai region is introduced and the advantage of such an approach is disusscd. ten patients were operated on by this approach. two illustrative cases are also presented.

Presented here is a system to standardize clinical studies of nutrient effects, using nutrient-specific physiological criteria. These guidelines are based mainly on analysis of the typical sigmoid curve of biological response to nutrients and are intended for design, interpretation, and pooling of studies of nutrient effects. Five rules have been articulated for individual studies of nutrients,...

The logistic sigmoid function curve provides an accurate description of the baroreflex input-output relationship and is the most commonly used equation for this purpose. The threshold (Thr) and saturation (Sat) values for the baroreflex are commonly defined as the values of mean arterial pressure (MAP) at which the reflexly controlled variable (e.g., heart rate or sympathetic nerve activity) is...

Dry matter accumulation data for juvenile Indian Olive saplings was modelled using linear and non- regression models. The gathered bimonthly two years i.e., twelve readings. Linear, Quadratic, Power, Sigmoid, Exponential models performed quite well cumulative growth (Adj. R2 > 0.93). Sigmoid model (Chapman- Richard) demonstrated upper asymptotic values ranged between 179.96- 334.49 grams all...

Article history: Received 25 August 2008 Received in revised form 22 November 2008 Accepted 26 November 2008 Ecotones are gradual transitions between two adjacent ecological systems. Ecotones are characterized by their spatial properties which are reflected in an ecotone width and location and the temporal variation across time during succession or environmental change on both a local and a glo...

Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow v...