Buckling Cascade of Thin Plates: Forms, Constraints and Similarity

We experimentally study compression of thin plates in rectangular boxes with variable height. A cascade of buckling is generated. It gives rise to a self-similar evolution of elastic reaction of plates with box height which surprisingly exhibits repetitive vanishing and negative stiffness. These features are understood from properties of Euler's equation for elastica

Intra-plant variation in seed weight and seed protein content of cowpea

Open Access JournalSeed size and protein content are the major breeding objectives for cowpeas (Vigna unguiculata). However, intra-plant variation in these traits causes heterogeneous seed quality and seed depreciation. To determine the causes and severity of intra-plant variation in cowpea single seed weight and protein content, seeds from individual plants were analyzed in relation to their positional effects. Associations between positional variables and seed traits were revealed by additive Bayesian network analysis, and the graphical models were compared for different accessions. Intra-plant variation in single seed weight and protein content were large compared to the variations in genetic resources, and these variations are thought to be related to the source/sink ratio within a plant. In accessions with longer flowering periods, the later-flowering peduncles on the upper nodes produced comparatively larger seeds due to a greater availability of assimilated carbon from leaves that maintain their greenness. While, in accessions with shorter flowering periods, the earlier-flowering peduncles on the lower nodes produced relatively larger seeds because less carbon is available at the later filling periods due to rapid senescence. For all accessions, protein content was higher in seeds derived from later-flowering peduncles and in pods with lower seed numbers. The nitrogen source/sink ratio may be higher in the later filling period because of a smaller number of filling seeds and a higher availability of nitrogen remobilized from senescing leaves and stems

A study of incremental sheet forming by using water jet

In this work, a variant of the incremental sheet forming (ISF) process, namely the incremental sheet forming by using water jet (ISF-WJ), was studied. In the investigation, an ISF-WJ prototype machine was designed and developed. Different design concepts of the water jet nozzle were proposed and evaluated to achieve the maximum forming pressure by performing computational fluid dynamic (CFD) simulations. Based on the forming pressure distribution modeled by CFD simulations, finite element (FE) models were developed to study the sheet deformation behavior under the ISF-WJ process condition. Based on the understanding gained from the numerical study, experiments were conducted to validate the ISF-WJ process and the developed prototype machine. The results suggest that ISF-WJ is a feasible process to achieve improved surface finish of thin sheet parts. In addition, this study has found that water jet pressure plays an important role in preventing sheet wrinkling and obtaining an accurate geometry of formed parts

A Time- and Cost-Saving Method of Producing Rat Polyclonal Antibodies

Producing antibodies usually takes more than three months. In the present study, we introduce a faster way of producing polyclonal antibodies based on preparation of the recombinant oligopeptide as antigen followed by immunization of rats. Using this method, we produced antisera against two mouse proteins: ERGIC-53 and c-Kit. An expression vector ligated with a pair of complementary synthetic oligodeoxyribonucleotides encoding the protein was introduced into bacteria, and the recombinant oligopeptide fused with the carrier protein glutathione-S-transferase was purified. Wistar rats were immunized by injecting the emulsified antigen subcutaneously into the hind footpads, followed by a booster injection ­after 2 weeks. One week after the booster, the sera were collected and examined for the antibody titer by immunohistochemistry. Antisera with 1600-fold titer at the maximum were obtained for both antigens and confirmed for their specificity by Western blotting. Anti-­ERGIC-53 antisera recognized acinar cells in the sublingual gland, and anti-c-Kit antisera recognized spermatogenic and Leydig cells in the testis. These antisera were applicable to fluorescent double immunostaining with mouse monoclonal or rabbit polyclonal antibodies. Consequently, this method enabled us to produce specific rat polyclonal antisera available for immunohistochemistry in less than one month at a relatively low cost

Duodenum-Preserving Resection of the Head of the Pancreas: The Significance as a Diagnostic Therapy for the Lesion in the Pancreatic Head

A 75-year-old man who was diagnosed as having mucin-producing pancreatic cystic lesion ofthe main pancreatic duct by duodenoscopic examination was reported. Because of the low malignant potential of such lesions, duodenum-preserving resection of the head of the pancreas was performed, and the intra-operative histological examination showed no malig-nancy of the resected pancreatic head and no other surgical procedures, such as lymph-adenectomy nor pancreato-duodenectomy were necessary. The significance of this case report lies in that a less invasive operation should be selected at first to diagnose whether the lesion is malignant or not, and als0 that the selected operation itself must be sufficient to resect an adequate part of the pancreatic tissue involving the cystic lesion, ifnot malignant. Here, we report the process to select the procedure and the surgical technique

Relative risks of chronic kidney disease for mortality and end-stage renal disease across races are similar

Some suggest race-specific cutpoints for kidney measures to define and stage chronic kidney disease (CKD), but evidence for race-specific clinical impact is limited. To address this issue, we compared hazard ratios of estimated glomerular filtration rates (eGFR) and albuminuria across races using meta-regression in 1.1 million adults (75% Asians, 21% Whites, and 4% Blacks) from 45 cohorts. Results came mainly from 25 general population cohorts comprising 0.9 million individuals. The associations of lower eGFR and higher albuminuria with mortality and end-stage renal disease (ESRD) were largely similar across races. For example, in Asians, Whites, and Blacks, the adjusted hazard ratios (95% confidence interval) for eGFR 45-59 versus 90-104 ml/min per 1.73 m(2) were 1.3 (1.2-1.3), 1.1 (1.0-1.2), and 1.3 (1.1-1.7) for all-cause mortality, 1.6 (1.5-1.7), 1.4 (1.2-1.7), and 1.4 (0.7-2.9) for cardiovascular mortality, and 27.6 (11.1-68.7), 11.2 (6.0-20.9), and 4.1 (2.2-7.5) for ESRD, respectively. The corresponding hazard ratios for urine albumin-to-creatinine ratio 30-299 mg/g or dipstick 1+ versus an albumin-to-creatinine ratio under 10 or dipstick negative were 1.6 (1.4-1.8), 1.7 (1.5-1.9), and 1.8 (1.7-2.1) for all-cause mortality, 1.7 (1.4-2.0), 1.8 (1.5-2.1), and 2.8 (2.2-3.6) for cardiovascular mortality, and 7.4 (2.0-27.6), 4.0 (2.8-5.9), and 5.6 (3.4-9.2) for ESRD, respectively. Thus, the relative mortality or ESRD risks of lower eGFR and higher albuminuria were largely similar among three major races, supporting similar clinical approach to CKD definition and staging, across races