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121.
Maria-Grazia Ascenzi Andre Lutz Xia Du Laureen Klimecky Neal Kawas Talia Hourany Joelle Jahng Jesse Chin Yin Tintut Udo Nackenhors Joyce Keyak 《Journal of biomechanics》2014
To improve bone strength prediction beyond limitations of assessment founded solely on the bone mineral component, we investigated the effect of hyperlipidemia, present in more than 40% of osteoporotic patients, on multiscale structure of murine bone. Our overarching purpose is to estimate bone strength accurately, to facilitate mitigating fracture morbidity and mortality in patients. Because (i) orientation of collagen type I affects, independently of degree of mineralization, cortical bone?s micro-structural strength; and, (ii) hyperlipidemia affects collagen orientation and μCT volumetric tissue mineral density (vTMD) in murine cortical bone, we have constructed the first multiscale finite element (mFE), mouse-specific femoral model to study the effect of collagen orientation and vTMD on strength in Ldlr−/−, a mouse model of hyperlipidemia, and its control wild type, on either high fat diet or normal diet. Each µCT scan-based mFE model included either element-specific elastic orthotropic properties calculated from collagen orientation and vTMD (collagen-density model) by experimentally validated formulation, or usual element-specific elastic isotropic material properties dependent on vTMD-only (density-only model). We found that collagen orientation, assessed by circularly polarized light and confocal microscopies, and vTMD, differed among groups and that microindentation results strongly correlate with elastic modulus of collagen-density models (r2=0.85, p=10−5). Collagen-density models yielded (1) larger strains, and therefore lower strength, in simulations of 3-point bending and physiological loading; and (2) higher correlation between mFE-predicted strength and 3-point bending experimental strength, than density-only models. This novel method supports ongoing translational research to achieve the as yet elusive goal of accurate bone strength prediction. 相似文献
122.
A procedure for creating and imaging capillary bridges in slit-pore geometry is presented. High aspect ratio hydrophobic pillars are fabricated and functionalized to render their top surfaces hydrophilic. The combination of a physical feature (the pillar) with a chemical boundary (the hydrophilic film on the top of the pillar) provides both a physical and chemical heterogeneity that pins the triple contact line, a necessary feature to create stable long but narrow capillary bridges. The substrates with the pillars are attached to glass slides and secured into custom holders. The holders are then mounted onto four axis microstages and positioned such that the pillars are parallel and facing each other. The capillary bridges are formed by introducing a fluid in the gap between the two substrates once the separation between the facing pillars has been reduced to a few hundred micrometers. The custom microstage is then employed to vary the height of the capillary bridge. A CCD camera is positioned to image either the length or the width of the capillary bridge to characterize the morphology of the fluid interface. Pillars with widths down to 250 µm and lengths up to 70 mm were fabricated with this method, leading to capillary bridges with aspect ratios (length/width) of over 1001. 相似文献
123.
Eib DW Holling TM Zwijsen A Dewulf N de Groot E van den Eijnden-van Raaij AJ Huylebroeck D Martens GJ 《Mechanisms of development》2000,97(1-2):167-171
A novel transmembrane protein (designated X7365) containing two follistatin modules and an epidermal growth factor (EGF) domain has been described in the hypothalamic-pituitary axis of Xenopus laevis. We have now cloned the highly conserved mouse orthologue (M7365), and its mRNA was detected in many mesodermal and (neuro)ectodermal tissues in 8.5-day-old mouse embryos. During further development, M7365 mRNA expression became restricted to certain regions in the brain and to ganglia. In the adult mouse, the brain is the major site of M7365 expression. 相似文献
124.
We report here on the cloning of cDNAs coding bovine and equine orthologs of mouse epididymis-restricted and sperm-bound glutathione peroxidase 5 (GPX5), a selenium-independent member of the multigenic GPX family in mammals. The complete sequence of bovine GPX5 as well as a partial sequence of the equine GPX5 were characterized, conceptually translated and aligned with other known mammalian GPX5 proteins. Using Northern blotting assays, we show that the level of expression of GPX5 is high in bovine but low in equine and that in both species the regionalization of GPX5 expression in epididymis is not totally identical to what was reported for rodent mouse GPX5. An antibody was produced against GPX5 and used in Western blot assays as well as in immunohistochemistry assays on bovine epididymis sections. It shows that the protein is essentially present in the cytoplasmic compartment of the caput segment 2 epithelium of the bovine epididymis. Unlike in the mouse model, bovine GPX5 seems to be poorly secreted and does not seem to be present on cauda epididymal spermatozoa. 相似文献
125.
Sherwood Githens III Doris R. G. Holmquist Joelle F. Whelan John R. Ruby 《In vitro cellular & developmental biology. Plant》1980,16(9):797-808
Summary Interlobular and intralobular ducts isolated from the pancreas of the rat by digestion with collagenase and chymotrypsin were
cultured in an agarose matrix containing CMRL-1066 supplemented with insulin, dexamethasone,l-glutamine, soybean trypsin inhibitor, antibiotics, and fetal bovine serum. The cut ends of most interlobular ducts sealed
to create encolosed lumina. Some ducts retained their original cylindrical organization; others enlarged to varying degrees,
resulting in structures that ranged from cylindrical to spherical in shape. The duct walls consisted of viable epithelium
and connective tissue, although the amount of connective tissue declined with age. Both epithelial and connective tissue cells
became flattened in the enlarged ducts. Intralobular and small interlobular ducts often remained associated with the larger
interlobular ducts. These duct fragments have been cultured for as long as 6 weeks.
This study was supported by National Cancer Institute Grant CA 19177 through the National Pancreatic Cancer Project and by
Biomedical Research Support Grant RR 07196 from the Division of Research Resources, National Institutes of Health. 相似文献
126.
Paul Tavernier Jeroen Dewulf Sophie Roelandt Stefan Roels 《European Journal of Wildlife Research》2011,57(5):1065-1075
We describe the prototype of an electronic tool for risk assessment with dynamic ranking of wildlife-borne pathogens in function
of their need for surveillance. Data about pathogens, their hosts and occurrences are obtained from literature and are classified
as qualitative scores under six main criteria with their sub-criteria, corresponding to the elements of a standard risk assessment.
Pathogen-specific data are reviewed by experts. The information is processed per pathogen through an algorithm and through
summing up of the values obtained by converting four-tiered qualitative sub-criteria scores to weighted five-tiered numerical
values. For a consistent comparison between pathogens, the “unknown” sub-criteria scores are assigned a median value of 3,
allowing preservation of the sub-criteria concerned and their weights for the risk assessment, but minimizing the effect of
this score on the outcome. Irregular data availability is further accommodated by a different data processing for comprehensiveness
and refinement requirements, which is realised by a respective first- and second-level ranking of pathogens, the latter using
additional quantitative and qualitative data for the release assessment. Continuous data updates are necessary to reflect
the current situation in the field. Output flexibility is implemented by the possibility to run queries based on the choice
of a region, a specific target group susceptible to the pathogens and a set of weights for the sub-criteria. 相似文献
127.
128.
Kevin Holvoet Imca Sampers Benedicte Callens Jeroen Dewulf Mieke Uyttendaele 《Applied and environmental microbiology》2013,79(21):6677-6683
Fresh produce is known to carry nonpathogenic epiphytic microorganisms. During agricultural production and harvesting, leafy greens can become contaminated with antibiotic-resistant pathogens or commensals from animal and human sources. As lettuce does not undergo any inactivation or preservation treatment during processing, consumers may be exposed directly to all of the (resistant) bacteria present. In this study, we investigated whether lettuce or its production environment (irrigation water, soil) is able to act as a vector or reservoir of antimicrobial-resistant Escherichia coli. Over a 1-year period, eight lettuce farms were visited multiple times and 738 samples, including lettuce seedlings (leaves and soil), soil, irrigation water, and lettuce leaves were collected. From these samples, 473 isolates of Escherichia coli were obtained and tested for resistance to 14 antimicrobials. Fifty-four isolates (11.4%) were resistant to one or more antimicrobials. The highest resistance rate was observed for ampicillin (7%), followed by cephalothin, amoxicillin-clavulanic acid, tetracycline, trimethoprim, and streptomycin, with resistance rates between 4.4 and 3.6%. No resistance to amikacin, ciprofloxacin, gentamicin, or kanamycin was observed. One isolate was resistant to cefotaxime. Among the multiresistant isolates (n = 37), ampicillin and cephalothin showed the highest resistance rates, at 76 and 52%, respectively. E. coli isolates from lettuce showed higher resistance rates than E. coli isolates obtained from soil or irrigation water samples. When the presence of resistance in E. coli isolates from lettuce production sites and their resistance patterns were compared with the profiles of animal-derived E. coli strains, they were found to be the most comparable with what is found in the cattle reservoir. This may suggest that cattle are a potential reservoir of antimicrobial-resistant E. coli strains in plant primary production. 相似文献
129.
Berger Markus Sonderegger Thomas Alvarenga Rodrigo Bach Vanessa Cimprich Alexander Dewulf Jo Frischknecht Rolf Guinée Jeroen Helbig Christoph Huppertz Tom Jolliet Olivier Motoshita Masaharu Northey Stephen Peña Claudia A. Rugani Benedetto Sahnoune Abdelhadi Schrijvers Dieuwertje Schulze Rita Sonnemann Guido Valero Alicia Weidema Bo P. Young Steven B. 《The International Journal of Life Cycle Assessment》2020,25(4):798-813
The International Journal of Life Cycle Assessment - Assessing impacts of abiotic resource use has been a topic of persistent debate among life cycle impact assessment (LCIA) method developers and... 相似文献
130.
van Oers Lauran Guinée Jeroen B. Heijungs Reinout Schulze Rita Alvarenga Rodrigo A. F. Dewulf Jo Drielsma Johannes Sanjuan-Delmás David Kampmann Tobias C. Bark Glenn Uriarte Ainara Garcia Menger Pierre Lindblom Mats Alcon Lucas Ramos Manuel Sevilla Torres Juan Manuel Escobar 《The International Journal of Life Cycle Assessment》2020,25(11):2255-2273
The International Journal of Life Cycle Assessment - The methods for assessing the impact of using abiotic resources in life cycle assessment (LCA) have always been heavily debated. One of the main... 相似文献