An efficient Galerkin meshfree flat shell formulation is presented for the analysis of buckling behaviors of stiffened plate structures. Both plate bending and membrane deformations are approximated ...by the reproducing kernel particle method (RKPM). The governing equation is transformed into a weak form, and it is discretized by the scattered nodes. The stiffness matrix is numerically integrated with the nodal integration technique, i.e., the stabilized conforming nodal integration (SCNI). The RKPM and SCNI based flat shell modeling approach can address the shear locking problem. Additionally, the present discretization is further improved by involving a drilling rotation component, which is to effectively model the stiffeners. There are six degrees of freedom per node. A singular kernel is also introduced into a set of the interpolants to model the web/flange connection, as well as the imposition of the essential boundary conditions. A generalized eigenvalue problem is analyzed for evaluating buckling loads/modes of the stiffened plate structures. The accuracy of the numerical results and the effectiveness of the proposed method are examined through several numerical examples.
•An improved meshfree flat shell formulation is presented.•The flat shell formulation is discretized by reproducing kernel particle method.•Stiffened plate structures are analyzed.•High accuracy computations are carried out employing the present formulation.
During forensic casework, it is vital to be able to obtain valuable information from burnt bone fragments to ascertain the identity of the victim. Here, we report the findings of an experimental ...study on burnt bovine compact bone segments. Compact bones were cut to size and heated in an electric furnace at a temperature range of 100–1,100 °C with 100 °C increments. Heat-induced alterations to the bone color, weight, volume, and density were monitored using gross morphology and micro-focus X-ray computed tomography. We found that the increase in temperature caused the color of the compact bones to change in order of yellow, brown, gray, and white. In contrast to the weight reduction that occurred immediately after burning, we measured no significant reduction in volume even at 600 °C; however, volume reduced drastically once the temperature reached 700 °C. Light microscopic histological observations of burnt bone revealed heat-induced alterations such as cracking and separation of the osteons at higher temperatures. In addition to these findings, we sought to examine the survival of DNA in the burnt bones using polymerase chain reaction of mitochondrial DNA. No amplification was found in the specimens burnt at 250 °C or higher, indicating the likely difficulty in testing the DNA of burnt bones from forensic casework. The results of this study will enable an estimation of the burning temperatures of burnt bones found in forensic cases and will provide an important framework with which to interpret data obtained during anthropological testing and DNA typing.
SUMMARY
Gastric pull-up is a common procedure to reconstruct the continuity of the upper digestive tract after esophageal resection. However, this technique sometimes causes postoperative anastomotic ...leakage or stricture, resulting from insufficient blood flow at the distal end. To overcome this problem, additional microvascular venous anastomoses were performed. The purpose of this study was to compare the outcomes of post-surgical anastomotic leakage and stricture in patients with and without additional microvascular venous superdrainage after cervical esophageal and hypopharyngeal resection and gastric tube reconstruction. A total of 29 consecutive patients with esophageal or hypopharyngeal cancer who underwent total esophagectomy and hypopharyngectomy with gastric tube reconstruction in the National Organization Nagasaki Medical Center between April 2014 and May 2016 were analyzed in this study. Of these patients, 20 underwent additional venous anastomoses (superdrainage group), and 9 did not undergo additional procedures (standard group). We compared the frequency of post-surgical stricture and leakage in the two groups retrospectively. Three of nine patients (33.3%) developed postoperative leakage in the standard group, and 1 of 20 (5.0%) did so in the superdrainage group. Six of nine patients (66.7%) showed postoperative anastomotic stricture in the standard group, but none did so in the superdrainage group. Patients who did not undergo additional venous superdrainage were significantly more likely to develop postsurgical leakage (P < 0.05, Chi-square test) and anastomotic stricture (P < 0.001, Chi-square test). Our study revealed that only additional venous anastomoses could reduce the incidence of postoperative anastomotic leakage and stricture. This procedure is of merit to perform after total esophagectomy and hypopharyngectomy with gastric tube reconstruction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Dual phase 980 MPa grade (DP980) steel sheets were resistance spot welded using a pulsed current, and the effects of the pulsed current on the strength properties of the joints were investigated. The ...pulsed current improved the mechanical properties of the joints in cross tensile tests. In situ observations during tear tests revealed that the ductility of the nugget was improved and that the propagation of cracks into the nugget was inhibited when the pulsed current was used. Microstructural observations and electron probe microanalysis (EPMA) of the nugget showed that the segregation of phosphorus at the nugget was reduced in the joint welded using the pulsed current, suggesting that the pulsed current improved the ductility of the nugget by altering their microstructures.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The control of magnetism with an electric field is a challenging area with the potential to affect fields related to magnetic data storage, sensors and magnetic random access memory. Although there ...are some successful examples of such control based on the use of magnetic metals and semiconductors, energy loss caused by current flow is a problem that needs to be addressed. In particular, the repeatable control of magnetization with an electric field can be disturbed by joule heat loss. In this regard, non-centrosymmetric insulating magnets are good candidates for controlling magnetization without energy loss, in which the linear magnetoelectric effect has an essential role. Moreover, such magnets exhibit an unconventional magneto-optical effect, which allows the time-resolved detection of the magnetization direction. Here, we show a periodic oscillation of the magnetization direction by ±20 in a non-centrosymmetric soft magnet (Cu,Ni)B2O4, which is induced by an a.c. electric field of 2 kHz. The present study provides a strategy for identifying materials in which the magnetization direction can be modulated at high speed with an electric field.
ABSTRACT
Small hepatocytes have hepatocyte-like characteristics and high proliferation activity. Most small hepatocyte studies report on in vitro rat or human hepatocytes. Only a few studies of small ...hepatocytes after bile duct ligation have been reported, and none of these have focused on these cells in birds. In this study, small hepatocytes appearing in bile duct ligation chicken liver were examined using the morphological method with histological, immunohistochemical, and ultrastructural studies. Nine Boris Brown hens (over 744-d old) were used. In all chickens, both the common hepatoenteric duct and hepatocystic duct were ligated, and the livers were examined 1, 4, 6, 9, and 13 weeks after bile duct ligation. Histologically, the small cells were half the size of normal liver cells, and mitotic figures were often observed. The nuclei showed two forms: large and small. Many small cells were negative for periodic acid-Schiff stain, but positive cells were rarely observed. The cells existed in colonies on the side of the sinusoid of the hepatic lamina. Immunohistochemically, the small cells with large nuclei were strongly positive for CD44, albumin and proliferation cell nuclear antigen, and the cells with small nuclei were weakly positive. In the CD44-positive cell colony, negative cells were often observed to have mature hepatocyte-like morphology. Moreover, many of the cells were PAN cytokeratin negative. Ultrastructurally, the small cells had more nuclei with rich heterochromatin, poor cytoplasmic organelles, and narrow cytoplasm with a high electron density than mature hepatocytes. Moreover, cells having a middle ultrastructural characteristic existed between the small cells and mature hepatocytes. The small hepatocellular colony of the chicken appeared as a regeneration-related change in the liver after bile duct ligation. The cell had high cell proliferation activity and morphological, immunohistochemical, and ultrastructural characteristics similar to those of the mammalian small hepatocyte, as well as a similar progenitor cell.
Highlights • We showed variations of the Japanese face from 3D facial images of 1126 individuals. • These results can be used as standard reference data for the facial image comparison. • The ...statistics were carefully acquired by making good use of the 3D capture system. • The statistics consists of a larger Japanese sample than that has been reported before. • All results except those for the “upper/lower lip ratio” showed normal distribution.
Awareness of variations in the hepatic vasculature and biliary system is extremely important for avoiding iatrogenic injury in upper-abdominal surgery. The objective of this study is to describe a ...rare case of abnormal vascular and biliary structures in the hepatocystic triangle (HCT) (the modern Calot’s triangle). During anatomical dissection of the coeliac trunk (CT) in an old man, the authors observed the presence of a hepatosplenic trunk arising from the CT and bifurcating into common hepatic and splenic arteries. The common hepatic artery divided into hepatic artery proper and gastroduodenal artery. The presence of accessory right hepatic artery (ARHA) arising from the superior mesenteric artery was also notable. The aberrant artery ascended retropancreatically ventral to the splenic vein, then posterolaterally to the portal vein before termination into the right hepatic lobe in the HCT. Within this triangle, there was an aberrant bile duct originating in the right hepatic lobe and ending in the common hepatic duct. This accessory duct crossed the ARHA and an associated branch (the cystic artery). There is no known previous report on the co-existence of an ARHA and an aberrant bile duct within the HCT, in addition to the hepatosplenic trunk. The clinical implications of the current case are addressed in discussion.
Objective
Streptococcus mutans, a major pathogen of dental caries, is considered to be one of the causative agents of infective endocarditis (IE). Two types of cell surface collagen‐binding proteins, ...Cnm and Cbm, have been identified in the organism. The aim of the present study was to analyze these proteins as possible etiologic factors for IE.
Materials and Methods
The binding activities of S. mutans strains to collagen types I, III, and IV were analyzed relative to the presence of Cnm and Cbm, as were their adhesion and invasion properties with human umbilical vein endothelial cells (HUVEC). In addition, distributions of the genes encoding Cnm and Cbm in S. mutans‐positive heart valve specimens extirpated from IE and non‐IE patients were analyzed by PCR.
Results
Most of the Cbm‐positive strains showed higher levels of binding to type I collagen as well as higher rates of adhesion and invasion with HUVEC as compared to the Cnm‐positive strains. Furthermore, the gene encoding Cbm was detected significantly more frequently in heart valve specimens from IE patients than from non‐IE patients.
Conclusions
These results suggest that the collagen‐binding protein Cbm of S. mutans may be one of the potential important factor associated with the pathogenesis of IE.
BACKGROUND Epigenetic regulation may be involved in modulation of gene expression during the normal cyclic changes of the human endometrium. We investigated expression of DNA methyltransferases ...(DNMTs) in endometrium during the menstrual cycle and the influence of sex steroid hormones on DNMT in endometrial stromal cells (ESC) in culture. METHODS Expression of DNMT1, DNMT3a and DNMT3b was assessed by immunohistochemistry and real-time RT–PCR in endometrial tissue (n = 42 women). ESC (n = 3 women) were cultured with estradiol and medroxyprogesterone acetate (E + MPA) for 17 days, and DNMT mRNA levels were measured by real-time RT–PCR. RESULTS Nuclei of both epithelial and stromal cells immunostained for DNMT1, DNMT3a and DNMT3b during each phase of the menstrual cycle. Tissue levels of DNMT1 and DNMT3a mRNA were significantly lower in the mid-secretory phase than in the proliferative phase (P < 0.01). For DNMT3b, the change in mRNA levels showed a similar trend to that for DNMT3a. In ESC culture, DNMT3a and DNMT3b mRNA levels were significantly decreased by E + MPA treatment (P < 0.01 and P < 0.05, respectively) at Day 8 and Day 17. CONCLUSIONS DNMT mRNAs declined in the human endometrium during the secretory phase, and E + MPA down-regulated DNMT3a and DNMT3b mRNAs in ESC in culture. These results suggest that DNMTs have regulatory functions in gene expression that is associated with decidualization.
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