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Development of hypertension stems from both environmental and genetic factors wherein the kidney plays a central role. Spontaneously hypertensive rats (SHR) and the nonhypertensive Wistar-Kyoto (WKY) controls are widely used as a model for studying hypertension. The present study examined the renal gene expression profiles between SHR and WKY at a prehypertensive stage (3 wk of age) and hypertensive stage (9 wk of age). Additionally, age-related changes in gene expression patterns were examined from 3 to 9 wk in both WKY and SHR. Five to six individual kidney samples of the same experimental group were pooled together, and quadruplicate hybridizations were performed using the National Institute of Environmental Health Sciences Rat version 2.0 Chip, which contains ~6,700 genes. Twenty two genes were found to be differentially expressed between SHR and WKY at 3 wk of age, and 104 genes were differentially expressed at 9 wk of age. Soluble epoxide hydrolase (Ephx2) was found to be significantly upregulated in SHR at both time points and was the predominant outlier. Conversely, elastase 1 (Ela1) was found to be the predominant gene downregulated in SHR at both time points. Analysis of profiles at 3 vs. 9 wk of age identified 508 differentially expressed genes in WKY rats. In contrast, only 211 genes were found to be differentially expressed during this time period in SHR. The altered gene expression patterns observed in the age-related analysis suggested significant differences in the vascular extracellular matrix system between SHR and WKY kidney. Together, our data highlight the complexity of hypertension and the numerous genes involved in and affected by this condition. soluble epoxide hydrolase; hypertension; arachidonic acid; elastase; real-time polymerase chain reaction

Various applications in science and engineering depend upon computing real solutions to systems of analytic equations which depend upon real parameters. Locally in the parameter space, the qualitative behavior of the solutions remains the same except at critical parameter values. This article develops a singular value homotopy that aims to compute critical parameter values. Several examples are presented including computing critical parameter values for nonlinear boundary value problems, turning points for a steady-state system connected to learning and memory, and computing the maximum Gaussian curvature of a surface. [ABSTRACT FROM AUTHOR]

Implicit–Explicit (IMEX) schemes are widely used for time integration methods for approximating solutions to a large class of problems. In this work, we develop accurate a posteriori error estimates of a quantity-of-interest for approximations obtained from multi-stage IMEX schemes. This is done by first defining a finite element method that is nodally equivalent to an IMEX scheme, then using typical methods for adjoint-based error estimation. The use of a nodally equivalent finite element method allows a decomposition of the error into multiple components, each describing the effect of a different portion of the method on the total error in a quantity-of-interest. [ABSTRACT FROM AUTHOR]

In this paper we analyze the convergence of the domain decomposition method applied to transport problems on networks. In particular, we derive estimates for the number of required iterations for linear problems. These estimates can be used to determine when the implementation of domain decomposition methods would be beneficial for this type of problems. [ABSTRACT FROM AUTHOR]

This paper is a review of the progress of daylighting technology in the UK. It recalls the first recorded quantitative studies in 1865 and traces developments from the work of P. J. Waldram in 1923 to the continuing research of the present day in the context of energy conservation. Methods of calculating and measuring daylight are reviewed as well as those for calculating and predicting the amount of sunlight received. Work on the subjective aspects of view, adequacy and glare is reviewed, together with their incorporation into standards of provision. An overall window design procedure using current knowledge about subjective and objective environmental requirements is suggested. [ABSTRACT FROM PUBLISHER]

This paper discusses daylight glare as a source of visual discomfort in terms of glare from the unobstructed sky and not glare related to direct or reflected sunlight. There is a difference between the glare experienced from a window and the glare experienced from a large source of artificial light of the same subtended area as the sky, due to the pyschological differences in the visual content of the field of view. There is also a difference in the discomfort glare produced by one small source or a number of small sources and a source with the same glare index subtending a large solid angle, due to the effect of the larger source on the adaptation level of the visual mechanism. The paper reviews the laboratory studies using artificial light sources of large area which were carried out in England and the USA and also the studies using daylight seen through real windows which were carried out in France and in England independently. The link between the practical studies and the laboratory studies is indicated and the derivation of quantitative requirements is shown. The analysis of the theoretical results indicates the effect of the various parameters involved. The conclusion is that discomfort glare from a single window (except for a rather small one) is practically independent of size and distance from the observer but is critically dependent on the sky luminance. Practical guidance is given on the design of windows and their surroundings to reduce the problems of glare from the sky, which is otherwise certain to be uncomfortable for a very large part of the year. The requirements for the balance of interior and exterior luminances are discussed, and a method of calculation and its practical application is put forward. [ABSTRACT FROM PUBLISHER]

The glare ratings of 17 commercial luminaires have been calculated and compared for the British and German systems of discomfort glare limitation. For some circumstances it is clear that there are considerable differences between the two systems but simple conversion tables are derived relating to room surface-reflectance and flux fraction ratio, which when applied enable a basic linear relationship between the two glare ratings to be used for most practical circumstances. [ABSTRACT FROM PUBLISHER]

The relationship of preferred ceiling luminance to that of recessed louvered fittings at different luminance levels was determined by observations in a model representing a windowless office. By optical simulation, observations were also made to determine optimum luminance of surface-mounted fittings in relation to illuminance. Preferred luminance levels gave a degree of glare approaching IES recommended limits at 500 lux, but a lower degree was required at higher levels. Preferred ceiling luminances with the surface-mounted fittings were in the region of 150-200 cd/m2. [ABSTRACT FROM PUBLISHER]

A field study has been made in eight offices in a new municipal building to determine the fluorescent lamp colours preferred by the staff for supplementing daylight and providing the night-time lighting. Four of the offices were glazed with clear glass and four with tinted 'Anti-sun' glass. Office areas and ceiling heights varied as did the illumination levels in the different offices. It is concluded that for supplementing natural daylight the Daylight (CCT 4300 K) lamp is best on account of its compatibility with daylight and its high luminous efficacy. This lamp was also well accepted for night-time lighting. The White (CCT 3500 K) lamp was in general the second choice. [ABSTRACT FROM PUBLISHER]

Possible methods of lighting deep hospital-ward-units, having restricted fenestration and reduced ceiling height have been investigated at the Building Research Station in co-operation with the Department of Health and Social Security. The experimental work was conducted in a full-scale mock-up of a six-bed bay, 7-9 m deep and 6-25 m wide with a 2-75 m ceiling height. With such a ceiling height and restricted fenestration, the daylight falls below the recommended minimum daylight factor and a sense of gloominess at the rear of the ward is experienced. Methods of supplementing the available daylight with artificial lighting were developed to dispel the gloominess by increasing the luminance of critical surfaces. Recommended levels of additional luminance required on the upper quarter of the side walls at the back of the bed-space and on the window wall were determined by subjective observations for glazed areas of 30 and 20 per cent of the window wall area. The results are summarized in tables, and details of experimental designs of suitable lighting fittings are given. [ABSTRACT FROM PUBLISHER]