A technique for combined dynamic compression-shear test

It is critically important to study the dynamic response of materials under a combined compression-shear loading for developing constitutive laws more accurately and fully. We present a novel technique to achieve the combined compression and shear loadings at high strain rates. The main apparatus consists of a strike bar, an incident bar, and two transmission bars. The close-to-specimen end of the incident bar is wedge-shaped with 90°. In each experiment, there are two identical specimens, respectively, agglutinated between one side of the wedge and one of transmission bars. When a loading impulse travels to specimens along the incident bar, because of the special geometrical shape, the specimen-incident bar interface gets an axial and a transverse velocity. Specimens endure a combined compression-shear loading at high strain rates. The compression stress and strain of the specimens are deduced from signals recorded by strain gages mounted on the bars. The shear stress is measured by two piezoelectric transducers of quartz (Y-cut with rotation angle 17.7°) embedded at the close-to-specimen end of transmission bars; the shear strain is measured with a novel optical technique, which is based on the luminous flux method. An analytic model was proposed and validated by the numerical simulations. The simulation results yield good agreement with the analytic results. The proposed technique was then validated through experiments carried out on lead specimens, by comparing experimental results with that of the split Hopkinson pressure bar experiments.

The technique and outcomes of branch-patch arterial reconstruction in living donor liver transplantation

BACKGROUND

Although living donor liver transplantation (LDLT) is now an established therapeutic modality for end-stage liver disease, technical dilemmas exist. The pretransplant imaging findings may not clearly define the surgical anatomy of the hepatic artery (HA), especially its diameter. A tiny artery (<2 mm) has always been found during the hilar dissection. Its size is discrepant to the diameter to the recipient arterial stump. The aim of this paper was to report a hepatic arterial reconstruction technique for small diameter (<2 mm) vessels in a partial liver graft.

METHODS

Since January 2002 to May 2007, we performed 9 LDLT with small hepatic arteries (<2 mm), which were analyzed retrospectively for this report. In this technique, we transect the donor hepatic artery proximally and distally to the tiny graft artery, take off and create a patch for arterial anastomosis. Computed tomographic angiography is used to evaluate the vascular anatomy and to measure the diameter of the graft HAs.

RESULTS

All donors were discharged without any vascular complications. One donor experienced a bile leakage from the dissections plane of the liver, which was treated by draining the abdominal cavity. Eight of the 9 patients survived without evidence of hepatic artery thrombosis during 32 months (range, 14-72); one subject died due to cytomegalovirus infection.

CONCLUSION

The arterial reconstruction technique enabled use of tiny arteries, eliminating the problems of diameter discrepancy without increasing donor complications.

Can body mass index, waist circumference, waist-hip ratio and waist-height ratio predict the presence of multiple metabolic risk factors in Chinese subjects?

BACKGROUND

Obesity is associated with metabolic risk factors. Body mass index (BMI), waist circumference, waist-hip ratio (WHR) and waist-height ratio (WHtR) are used to predict the risk of obesity related diseases. However, it has not been examined whether these four indicators can detect the clustering of metabolic risk factors in Chinese subjects.

METHODS

There are 772 Chinese subjects in the present study. Metabolic risk factors including high blood pressure, dyslipidemia, and glucose intolerance were identified according to the criteria from WHO. All statistical analyses were performed separately according to sex by using the SPSS 12.0.

RESULTS

BMI, waist circumference and WHtR values were all significantly associated with blood pressure, glucose, triglyceride and also with the number of metabolic risk factors in both male and female subjects (all of P < 0.05). According to receiver operating characteristic (ROC) analysis, the area under curve values of BMI, waist circumference and WHtR did not differ in male (0.682 vs. 0.661 vs. 0.651) and female (0.702 vs. 0.671 vs. 0.674) subjects, indicating that the three values could be useful in detecting the occurrence of multiple metabolic risk factors. The appropriate cut-off values of BMI, waist circumference and WHtR to predict the presence of multiple metabolic risk factors were 22.85 and 23.30 kg/m² in males and females, respectively. Those of waist circumference and WHtR were 91.3 cm and 87.1 cm, 0.51 and 0.53 in males and females, respectively.

CONCLUSION

The BMI, waist circumference and WHtR values can similarly predict the presence of multiple metabolic risk factors in Chinese subjects.

New trends of HCV infection in China revealed by genetic analysis of viral sequences determined from first-time volunteer blood donors

Recently, we studied hepatitis C virus (HCV) sera-prevalence among 559 890 first-time volunteer blood donors in China. From randomly selected 450 anti-HCV positive donors, we detected HCV RNA in 270 donors. In this study, we amplified HCV E1 and/or NS5B sequences from 236 of these donors followed by DNA sequencing and phylogenetic analysis. The results indicate new trends of HCV infection in China. The HCV genotype distribution differed according to the donors' region of origin. Among donors from Guangdong province, we detected subtypes 6a, 1b, 3a, 3b, 2a, and 1a at frequencies of 49.7%, 31.0%, 7.6%, 5.5%, 4.1%, and 2.1%, respectively. Among donors from outside Guangdong, we detected 1b, 2a, 6a, 3b, 3a, 6e, and 6n at frequencies 57.1%, 13.2%, 11.0%, 9.9%, 4.4%, 2.2%, and 2.2%, respectively. Although we found no significant differences among regions in age or gender, subtype 6a was more common (P < 0.001) in donors from Guangdong than those from elsewhere, whilst subtypes 1b (P < 0.02) and 2a (P < 0.001) were more frequent outside Guangdong. Disregarding origins, the male/female ratio was higher for subtype 6a-infected donors (P < 0.05) than for subtype 1b donors, whilst the mean age of subtype 2a donors was 8-10 years older (P < 0.05) than that for all other subtypes. Detailed phylogenetic analysis of our sequence data provides further insight into the transmission of HCV within China, and between China and other countries. The predominance of HCV 6a among blood donors in Guangdong is striking and mandates studies into risk factors for its acquisition.

Bridging the gap between education and practice in public health, with particular reference to less-developed provinces in China

Ongoing healthcare system reform is one of the most important issues in China. There is an increasing awareness that public health education should be reformed to meet the demands of public health practice. This paper summarizes the current status of increasing public healthcare demand and public health service capacity in China, especially in less-developed provinces, and introduces the current public health educational system and public health administration structure. The paper also provides evidence for a considerable gap between public health education and practice, and suggests possible measures to bridge the gap.

Sonographic Assessment of Ceftriaxone-Associated Biliary Pseudolithiasis in Chinese Children

In this randomized, single-blind, case-controlled, prospective study, the incidence and outcome of ceftriaxone-associated biliary pseudolithiasis in Chinese children was evaluated via ultrasonography. A total of 108 children diagnosed with hepatobiliary infection or pneumonia were randomized to receive ceftriaxone or ceftazidime. Serial gallbladder sonograms were obtained on days 1, 5 − 7 and 10 − 14 of therapy. Gallstones were detected in 43.10% of patients in the ceftriaxone-treated group and in 2.00% of the ceftazidime-treated group. The incidence of pseudolithiasis was significantly higher in the ceftriaxone-treated than the ceftazidime-treated group. Biliary precipitation abnormalities appeared after 2 − 7 days of treatment. After gallstones were found, the drug was stopped and symptoms resolved within 1 − 2 days. This study suggests that the risk of ceftriaxone-associated biliary pseudolithiasis should be considered when treating Chinese children.

Gate-voltage control of chemical potential and weak antilocalization in Bi₂Se₃

We report that Bi₂Se₃ thin films can be epitaxially grown on SrTiO₃ substrates, which allow for very large tunablity in carrier density with a back gate. The observed low field magnetoconductivity due to weak antilocalization (WAL) has a very weak gate-voltage dependence unless the electron density is reduced to very low values. Such a transition in WAL is correlated with unusual changes in longitudinal and Hall resistivities. Our results suggest a much suppressed bulk conductivity at large negative gate voltages and a possible role of surface states in the WAL phenomena.

CEST-FISP: a novel technique for rapid chemical exchange saturation transfer MRI at 7 T

Chemical exchange saturation transfer (CEST) and magnetization transfer techniques provide unique and potentially quantitative contrast mechanisms in multiple MRI applications. However, the in vivo implementation of these techniques has been limited by the relatively slow MRI acquisition techniques, especially on high-field MRI scanners. A new, rapid CEST-fast imaging with steady-state free precession technique was developed to provide sensitive CEST contrast in ∼20 sec. In this study at 7 T with in vitro bovine glycogen samples and initial in vivo results in a rat liver, the CEST-fast imaging with steady-state free precession technique was shown to provide equivalent CEST sensitivity in comparison to a conventional CEST-spin echo acquisition with a 50-fold reduction in acquisition time. The sensitivity of the CEST-fast imaging with steady-state free precession technique was also shown to be dependent on k-space encoding with centric k-space encoding providing a 30-40% increase in CEST sensitivity relative to linear encoding for 256 or more k-space lines. Overall, the CEST-fast imaging with steady-state free precession acquisition technique provides a rapid and sensitive imaging platform with the potential to provide quantitative CEST and magnetization transfer imaging data.

Characterization of Durham virus, a novel rhabdovirus that encodes both a C and SH protein

The family Rhabdoviridae is a diverse group of non-segmented, negative-sense RNA viruses that are distributed worldwide and infect a wide range of hosts including vertebrates, invertebrates, and plants. Of the 114 currently recognized vertebrate rhabdoviruses, relatively few have been well characterized at both the antigenic and genetic level; hence, the phylogenetic relationships between many of the vertebrate rhabdoviruses remain unknown. The present report describes a novel rhabdovirus isolated from the brain of a moribund American coot (Fulica americana) that exhibited neurological signs when found in Durham County, North Carolina, in 2005. Antigenic characterization of the virus revealed that it was serologically unrelated to 68 other known vertebrate rhabdoviruses. Genomic sequencing of the virus indicated that it shared the highest identity to Tupaia rhabdovirus (TUPV), and as only previously observed in TUPV, the genome encoded a putative C protein in an overlapping open reading frame (ORF) of the phosphoprotein gene and a small hydrophobic (SH) protein located in a novel ORF between the matrix and glycoprotein genes. Phylogenetic analysis of partial amino acid sequences of the nucleoprotein and polymerase protein indicated that, in addition to TUPV, the virus was most closely related to avian and small mammal rhabdoviruses from Africa and North America. In this report, we present the morphological, pathological, antigenic, and genetic characterization of the new virus, tentatively named Durham virus (DURV), and discuss its potential evolutionary relationship to other vertebrate rhabdoviruses.

Transplantation of umbilical cord mesenchymal stem cells alleviates lupus nephritis in MRL/lpr mice

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease, which, despite the advances in immunosuppressive medical therapies, remains potentially fatal in some patients, especially in treatment-refractory patients. This study found that transplantation of umbilical cord mesenchymal stem cells (UC-MSCs) has the same therapeutic effect as transplantation of bone marrow mesenchymal stem cells (BM-MSCs), which has been reported to be efficient in treating SLE-related symptoms in MRL/lpr mice. Multi-treatment (at the 18th, 19th, and 20th weeks of age) of 1 × 10(6) UC-MSCs was able to decrease the levels of 24-h proteinuria, serum creatinine, and anti-double-stranded DNA (dsDNA) antibody, and the extent of renal injury such as crescent formation in MRL/lpr mice. A lower, but still significant, reduction in these parameters was also observed in mice receiving a single dose of UC-MSCs (at the 18th week). UC-MSCs treatment also inhibited expression of monocyte chemotactic protein-1 (MCP-1) and high-mobility group box 1 (HMGB-1) expression in a similar fashion. UC-MSCs labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) were found in the lungs and kidneys 1 week post infusion. In addition, after 11 weeks post UC-MSCs infusion, human cells were found in kidney of UC-MSCs-treated mice. These findings indicated that UC-MSCs transplantation might be a potentially promising approach in the treatment of lupus nephritis, possibly by inhibiting MCP-1 and HMGB-1 production.

Tris[2-(1H-imidazol-2-yl)imidazol-1-ido]cobalt(III)

In the title compound, [Co(C₆H₅N₄)₃], the Co^III atom adopts a distorted octa­hedral CoN₆ coordination geometry, arising from three N,N′-bidentate deprotonated 2,2′-biimidazole ligands. The dihedral angles between the five-membered rings of the ligands are 4.1 (2), 9.4 (2) and 10.5 (2)°. In the crystal, mol­ecules are linked by N—H⋯N hydrogen bonds, generating a layered network lying in (11).

Hexakis(dimethyl-ammonium) di-μ(6)-oxido-tetra-μ(3)-oxido-tetra-deca-μ(2)-oxido-octa-oxidodeca-vanadate(V) monohydrate

In the title compound, (C(2)H(8)N)(6)[V(10)O(28)]·H(2)O, the [V(10)O(28)](6-) polymetalate anion has crystallographic mirror symmetry with six V atoms and 12 O atoms lying on the mirror plane. Each of the V(V) atoms adopts a distorted octa-hedral geometry. Eight terminal O atoms are bonded to V(V) atoms with double bonds and the others act as bridging atoms. In the crystal structure, a network of N-H⋯O and O-H⋯O hydrogen bonds helps to establish the packing.