Renal function is crucially dependent on renal microstructure which provides the basis for the regulatory mechanisms that control the transport of water and solutes between filtrate and plasma and the urinary concentration. This study provides new, detailed information on mouse renal architecture, including the spatial course of the tubules, lengths of different segments of nephrons, histotopography of tubules and vascular bundles, and epithelial ultrastructure at well-defined positions along Henle's loop and the distal convolution of nephrons. Three-dimensional reconstruction of 200 nephrons and collecting ducts was performed on aligned digital images, obtained from 2.5-m-thick serial sections of mouse kidneys. Important new findings were highlighted: (1) A tortuous course of the descending thin limbs of long-looped nephrons and a winding course of the thick ascending limbs of short-looped nephrons contributed to a 27% average increase in the lengths of the corresponding segments, (2) the thick-walled tubules incorporated in the central part of the vascular bundles in the inner stripe of the outer medulla were identified as thick ascending limbs of long-looped nephrons, and (3) three types of short-looped nephron bends were identified to relate to the length and the position of the nephron and its corresponding glomerulus. The ultrastructure of the tubule segments was identified and suggests important implications for renal transport mechanisms that should be considered when evaluating the segmental distribution of water and solute transporters within the normal and diseased kidney. T he renal architecture is arranged elaborately to fulfill the physiologic demands for reabsorption of filtered substances and for urine concentration. The architecture includes the formation of the renal zones, the population of short-looped nephrons (SLN) and long-looped nephrons (LLN), the distribution of the tubule segments of nephrons, the tubular-vascular histotopography in medulla, and the epithelial configurations of the different tubule segments.From the 1960s to the 1980s, Kriz and others studied the renal microstructure, including the distribution of nephrons, the tubular-vascular relations in the medullary zones, and the ultrastructure of the epithelia along Henle's loop. Simultaneously, the diversities in renal structure were demonstrated between different species, including rat, mouse, hamster, and rabbit (1-3). In the late 1980s, a standard nomenclature for the kidney structure, which has been widely adopted, was published (4). With the development of digital techniques, three-dimensional (3D) representations of the tubule segments of nephrons were performed to a limited extent at the proximal tubules (PT) (5), distal tubule (6), and at the thin limbs (TL) of the LLN in the inner medulla (IM) (7) of rats. Two mathematical regionalbased models combining morphologic and immunohistochemical findings have been set up to simulate the urine concentration mechanism in rat medulla (8).At present, a large body of basic nephrol...

Abstract. Mice are prime targets of experimental gene modification and have become object of an increasing number of biologic studies in renal physiology, development, and molecular biology. Phenotypic changes in response to gene modification require detailed information on normal structure. However, detailed analyses of normal mouse kidney structure and organization are lacking. This study describes the 3D organization and ultrastructural, segmental variation of the mouse kidney proximal tubule. A total of 160 proximal tubules in three C57/BL/6J mouse kidneys were analyzed on 800 serial sections from each kidney from the surface to the inner stripe of the outer zone of medulla. All tubules were reconstructed in 3D and visualized by interactive computer graphics. A quantitative ultrastructural analysis of the mouse proximal tubule at every 300 to 400 m was performed. The 3D representation revealed a distinct organization of the mouse proximal tubule, each occupying a separate domain within the cortex. Superficial proximal tubules have long straight parts converging into clusters within the medullary rays. Tubules originating deeper within the cortex become longer and increasingly tortuous. In the medullary rays, these are arranged in layers outside the clusters of more superficial tubules. In contrast to rat and human kidney, no major segmental variation in the ultrastructure of the proximal tubule was identified, and no parameters enabled definition of distinct segments in this strain of mice. In conclusion, significant new information on the 3D organization of the murine proximal tubule has been obtained. Quantitative, ultrastructural analyses of mouse proximal tubules reveal substantial differences compared with other species.Over the last decade, the mouse kidney has become the target for an increasing number of functional and morphologic studies. Gene-deleted and transgenic mice have become important tools for the study of a variety of physiologic and pathophysiologic parameters. To be able to recognize structural changes in genetically modified kidneys, it is therefore pertinent to obtain information on the normal architecture of mouse nephrons.In the literature, structural and functional parameters of the mouse proximal tubule are often correlated to the segmentation well described in other species. The rat proximal tubule segmentation has been intensively studied at the ultrastructural level, subdividing it into three segments (1); studies on mouse proximal tubules often refer to this segmentation. Although the ultrastructure of mouse proximal tubules has been described to some extent (see reference 2), detailed information, including the verification of any segmental, structural variation is required.Only little information on the three-dimensional organization of the mouse renal proximal tubule is available, limited mainly to the identification of a convoluted and a straight part, the latter being located in the medullary rays. A more detailed description of the tubular organization may be of interest ...

Bisphosphonates inhibit bone loss through inhibition of osteoclast-mediated bone resorption. At low doses, vitamin D metabolites can prevent bone loss in models of osteopenia in rats by an antiresorptive effect, while at high doses they also stimulate osteoblast activity and show an anabolic effect. Therefore, combined therapy with bisphosphonates and vitamin D analogs might be expected to be more effective than either treatment alone.

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Highlights of the article " Solid oxide fuel cells powered by biomass gasification for high efficiency power generation"  Design and operation of a gasification-SOFC system with minimal gas cleaning  Experimental results from full load, part load and long-term tests with product gas  Electric efficiencies around 40% biomass-to-power for small-scale power generation  Modeled gasification-SOFC combined cycle concepts with efficiencies up to 62% ABSTRACT 10 Increased use of bioenergy is a very cost-effective and flexible measure to limit changes in the 11 climate and the infrastructure. One of the key technologies toward a higher implementation of 12 biomass is thermal gasification, which enables a wide span of downstream applications. In 13 order to improve efficiencies, flexibility and possibly costs of current biomass power 14 generating systems, a power plant concept combining solid oxide fuel cells (SOFC) and 15 gasification is investigated experimentally. The aim of the study is to examine the commercial 16 operation system potential of these two technologies. Investigations are done by combining 17 the commercial TwoStage Viking gasifier developed at the Technical University of Denmark 18 and a state-of-the-art SOFC stack from Topsoe Fuel Cell for high efficiency power 19 generation. A total of 5 tests were performed including polarization tests at various gas flows 20 to study part-load operation; and a longer test to investigate stability. The study shows 21 experimentally the potential and feasibility of a SOFC-gasification system with a commercial 22 gasifier and a SOFC stack by measuring the highest reported values of such a system, with 23 biomass-to-electricity efficiencies up to 43%. Results from related modeling studies are also ACCEPTED MANUSCRIPT 2 24 presented, showcasing the intriguing potential of the system with modeled cycle electric 25 efficiencies up to 62%. 26 27

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A nondestructive and noninvasive method for numeric characterization (quantification) of the structural composition of human bone tissue has been developed and tested. In order to quantify and to compare the structural composition of bones from 2D computed tomography (CT) images acquired at different skeletal locations, a series of robust, versatile, and adjustable image segmentation and structure assessment algorithms were developed. The segmentation technique facilitates separation from cortical bone and standardizes the region of interest. The segmented images were symbol-encoded and different aspects of the bone structural composition were quantified using six different measures of complexity. These structural examinations were performed on CT images of bone specimens obtained at the distal radius, humeral mid-diaphysis, vertebral body, femoral head, femoral neck, proximal tibia, and calcaneus. In addition, the ability of the noninvasive and nondestructive measures of complexity to quantify trabecular bone structure was verified by comparing them to conventional static histomorphometry performed on human fourth lumbar vertebral bodies. Strong correlations were established between the measures of complexity and the histomorphometric parameters except for measures expressing trabecular thickness. Furthermore, the ability of the measures of complexity to predict vertebral bone strength was investigated by comparing the outcome of the complexity analysis of the CT images with the results of a biomechanical compression test of the third lumbar vertebral bodies from the same population as used for histomorphometry. A multiple regression analysis using the proposed measures including structure complexity index, structure disorder index, trabecular network index, index of a global ensemble, maximal L-block, and entropy of x-ray attenuation distribution revealed an excellent relationship (r=0.959, r2=0.92) between the measures of complexity and compressive bone strength. In conclusion, the image segmentation techniques and the assessment of bone architecture by measures of complexity have been successfully applied to analyze high-resolution peripheral quantitative computed tomography (pQCT) and CT images obtained from the distal radius, humeral mid-diaphysis, third and fourth lumbar vertebral bodies, proximal femur, proximal tibia, and calcaneus. The proposed approach is of broad interest as it can be applied for the quantification of structures and textures originating from different imaging modalities in other fields of science.

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