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This paper is concerned with radially positive solutions of the k-Hessian equation involving a Matukuma-type source... [ABSTRACT FROM AUTHOR]

The present paper is concerned with the dynamic recrystallization of the Ti-6Al-4V alloy. Electron Backscatter Diffraction (EBSD) observations are performed after high-temperatures tensile tests, with the temperature ranging from 700 to ~950 °C, and the strain rates varying between 10−4 and 10−2/s. Based on the analysis of flow behavior, the dominant mechanism is identified, and a mechanism map is proposed. In particular, the conditions of 890 °C and strain rates ranging from 10−3 to ~10−2/s serve as the delineating boundary of dynamic recovery (DRV) and dynamic recrystallization (DRX). For superplastic deformation, the dominant softening mechanism is DRV. Consequently, the occurrence of continuous dynamic recrystallization (CDRX) can naturally be ascribed to the process of grain refinement. Then, a multi-scales physical-based constitutive model of CDRX is developed, demonstrating a good agreement is obtained between the experimental and calculated grain sizes, so the above model could be used to describe the grain growth for superplastic deformation. In conclusion, DRV and DRX in the superplastic forming of Ti-6Al-4V are studied in this study, the condition boundaries of their occurrence are distinguished, and a constitutive equation-based CDRX recrystallization mechanism is given, which might be employed in the fracture mechanism research. [ABSTRACT FROM AUTHOR]

The paper is devoted to investigating a semilinear parabolic equation with a nonlinear gradient source term: ut = uxx + xm|ux|p, t > 0, 0 < x < 1,where p > m + 2, m ≥ 0. Zhang and Hu [Discrete Contin. Dyn. Syst. 26 (2010) 767-779] showed that finite time gradient blowup occurs at the boundary and the accurate blowup rate is also obtained for super-critical boundary value. Throughout this paper, we present a complete large time behavior of a classical solution : is global and converges to the unique stationary solution in norm for subcritical boundary value, and blows up in infinite time for critical boundary value. Gradient growup rate is also established by the method of matched asymptotic expansions. In addition, gradient estimate of solutions is obtained by the Bernstein-type arguments. [ABSTRACT FROM AUTHOR]

This paper is concerned with two properties of positive weak solutions of quasilinear elliptic equations with nonlinear gradient terms. First, we show a Liouville-type theorem for positive weak solutions of the equation involving the m -Laplacian operator − Δ m u = u q | ∇ u | p in R N , where N ⩾ 1 , m > 1 and p , q ⩾ 0. The technique of Bernstein gradient estimates is utilized to study the case p < m. Moreover, a Liouville-type theorem for supersolutions under subcritical range of exponents q (N − m) + p (N − 1) < N (m − 1) is also established. Then, we use a degree argument to obtain the existence of positive weak solutions for a nonlinear Dirichlet problem of the type − Δ m u = f (x , u , ∇ u) , with f satisfying certain structure conditions. Our proof is based on a priori estimates, which will be accomplished by using a blow-up argument together with the Liouville-type theorem in the half-space. As another application, some new Harnack inequalities are proved. [ABSTRACT FROM AUTHOR]

Objective: The bone marrow mesenchymal stem cells (BMSCs) have the capacity to differentiate into insulin-producing cells (IPCs) in vitro. However, low differentiation efficiency and poor maturity are the main obstacles. To investigate the feasibility of BMSCs differentiation into IPCs in diabetic pancreatic microenvironment of pigs., Methods: BMSCs were isolated and purified from the bone marrow of a 4-week-old male pig. Fifteen female pigs (aged 8 to 10 weeks, weighing 8 to 10 kg) were randomly divided into 3 groups: normal control group (group A, n=5), diabetic control group (group B, n=5), and BMSCs transplanted group (group C, n=5). The pigs of groups B and C were treated by auris vein injections of streptozocin and alloxan for 3 days to induce diabetes mellitus (DM) model, whose blood glucose level 2 days all greater than 17 mmol/L was successful DM model. A total of 1.1 mL of the 3rd passage BMSCs labeled with enhanced green fluorescent protein (EGFP), with cell density of 5 x 10(7)/ mL, were injected into subcapsular pancreas of group C at multiple points, normal saline at the same dosage into those of groups A and B. After 30 days of monitoring blood glucose, the histological analysis of islet number and size were done; the immunofluorescence staining was used to detect the protein expression of insulin in the new-formed islets. The EGFP+ cells were collected from the sections using laser-capture microdissection; RT-PCR was used to detect insulin mRNA and pancreatic and duodenal homeobox factor 1 (PDX1) mRNA expressions from EGFP+ cells, and the insulin and sex determining region of the Y chromosome (SRY) genes were detected by fluorescence in situ hybridization (FISH)., Results: The blood glucose level decreased significantly in group C when compared with that in group B from 18 days and gradually decreased with time (P < 0.05). The histological observation showed that the number of islets was increased significantly in group C when compared with that in group B (10.9 +/- 2.2 vs. 4.6 +/- 1.4, P < 0.05), and there was no significant difference when compared with that in group A (10.9 +/- 2.2 vs.12.6 +/- 2.6, P > 0.05). The size of new-formed islets in group C was significantly smaller than that in group A [(47.2 +/- 19.6) microm vs. (119.6 +/- 27.7) microm, P < 0.05]. The immunofluorescence staining showed that new-formed islets of group C expressed insulin protein. RT-PCR showed that the microdissected EGFP+ cells of group C expressed insulin mRNA and PDX-1 mRNA. FISH showed that the new-formed islet cells of group C contained SRY gene in Y chromosome and insulin double positive cells., Conclusion: BMSCs can differentiate into IPCs in diabetic pancreatic microenvironment of pigs.

Objectives: : This study observed whether mesenchymal stem cells (MSCs) adopt beta-cell fate upon diabetic microenvironment., Methods: : We transplanted male porcine MSCs to diabetic female pigs by directly injecting into pancreas. Recipients' sera and pancreatic tissue were analyzed to assess the therapeutic effect. Islets were collected from the sections using laser-capture microdissection. The RNAs from these specimens were extracted and analyzed for insulin and pancreas duodenum homeobox 1 messenger RNA (mRNA) expression. SRY gene was detected from the specimens., Results: : Compared with untreated diabetic controls, blood glucose level decreased greatly in recipients from 18 days (15.44 +/- 0.31 mmol/L vs 16.66 +/- 0.11 mmol/L) and insulin increased from 14 days (0.048 +/- 0.006 U/L vs 0.030 +/- 0.004 U/L). Hematoxylin and eosin-stained sections demonstrated increased islets in recipients and few lymphocytes present. The newly formed islets were smaller than normal islets (47.2 mum +/- 19.6 vs 119.6 +/- 27.7 mum). Reverse transcription-polymerase chain reaction showed that microdissected cells expressed insulin and pancreas duodenum homeobox 1 mRNA (79.3% +/- 16.2% of control, 65.2% +/- 14.8% of control, respectively). Immunoreactivity showed that the transplanted MSCs expressed insulin. SRY gene and insulin mRNA double-positive cells were found in microdissected cells by fluorescence in situ hybridization., Conclusions: This study shows that MSCs could adopt beta-cell fate in diabetic pancreatic microenvironment without obvious immune rejections. Stem cell transplantation in orthotope is a promising therapy for diabetes.

To analyze the polymorphism of TAP gene and the shared rates of alleles between mothers and their infants in Chinese patients with pre-eclampsia, TAP1 and TAP2 genotyping was performed by the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in 42 patients, 106 normal pregnant women, and their neonates. The allelic frequency of TAP and the alleles shared in maternal-fetus were compared and analyzed in the two groups. Our results showed that, with totally eight alleles of TAP1 and TAP2 examined in the samples, no significant difference was found in allelic frequencies between pre-eclampsia group and control group, as well as between mothers and their neonates. Similar finding was obtained in the comparison with shared alleles. In conclusion, our results do not support a role for the polymorphisms of TAP in the etiology of pre-eclampsia.

The activity of the NK cells in patients with preeclampsia was studied to investigate the pathogenesis of preeclampsia. By using MTT and 51Cr releasing technique, the proliferation and killing ability of the NK cells in maternal and umbilical blood from preeclampsia patients (n = 18) and normal third trimester pregnant women (n = 18) were detected. The NK-92 cell line was as the positive control. The results showed that the NK cell counts of umbilical blood in preeclampsia patients and normal third trimester pregnant women were significantly greater than those of maternal blood (both P<0.05). Compared with that in normal third trimester pregnant women, the proliferative ability of the NK cells in preeclampsia patients was apparently increased (P<0.05). Compared with that in maternal blood, the proliferative ability of the NK cells in umbilical blood from both preeclampsia patients and normal third trimester pregnant women was dramatically increased. The killing ability of the NK cells in preeclampsia patients was significantly higher than that in normal third trimester pregnant women (P <0.05). It was suggested that both number and function of the NK cells in preeclampsia women were increased, and that in umbilical blood was greater than that in maternal blood, speculating that the function of the NK cells may affect the maintenance of the maternal and fetal immune tolerance during pregnancy.