Photo-stability of pulsed laser deposited Ge(x)As(y)Se(100-x-y) amorphous thin films

Quest for photo-stable amorphous thin films in ternary Ge(x)As(y)Se(100-x-y) chalcogenide system is reported. Studied layers were fabricated using pulsed laser deposition technique. Scanning electron microscope with energy dispersive X-ray analyzer, Raman scattering spectroscopy, transmittance measurements, variable angle spectroscopic ellipsometry, and non-linear imaging technique with phase object inside the 4f imaging system were employed to characterize prepared thin films. Their photo-stability/photo-induced phenomena in as-deposited and relaxed states were also investigated, respectively. In linear regime, we found intrinsically photo-stable relaxed layers within Ge(20)As(20)Se(60) composition. This composition presents also the highest optical damage threshold under non-linear optical conditions.

A link between endoplasmic reticulum stress-induced β-cell apoptosis and the group VIA Ca2+-independent phospholipase A2 (iPLA2β)

Endoplasmic reticulum (ER) stress is becoming recognized as an important contributing factor in various diseases, including diabetes mellitus. Prolonged ER stress can cause β-cell apoptosis; however, the underlying mechanism(s) that contribute to this process are not well understood. Early reports suggested that arachidonic acid metabolites and a Ca(2+)-independent phospholipase A(2) (iPLA(2)) activity play a role in β-cell apoptosis. The PLA(2) family of enzymes catalyse the hydrolysis of the sn-2 substituent (i.e. arachidonic acid) of membrane phospholipids. In light of our findings that the pancreatic islet β-cells are enriched in arachidonate-containing phospholipids and express the group VIA iPLA(2)β, we considered the possibility that iPLA(2)β participates in ER stress-induced β-cell apoptosis. Our work revealed a novel mechanism, involving ceramide generation and triggering of mitochondrial abnormalities, by which iPLA(2)β participates in the β-cell apoptosis process. Here, we review our evidence linking ER stress, β-cell apoptosis and iPLA(2)β. Continued studies in this area will increase our understanding of the contribution of iPLA(2)β to the evolution of diabetes mellitus and will further our knowledge of factors that influence β-cell health in diabetes mellitus and identify potential targets for future therapeutic interventions to prevent β-cell death.

Osteoblastic cell response on fluoridated hydroxyapatite coatings: the effect of magnesium incorporation

Magnesium (Mg) ions were incorporated into fluoridated hydroxyapatite (HA) coating by the sol-gel dip-coating method. Mg in the coating was measured by x-ray photoelectron spectroscopy (XPS). The changes of calcium and magnesium concentrations were recorded to monitor the dissolution behavior of the coatings. In vitro cell responses were evaluated using MG63 cells in terms of cell morphology, proliferation and differentiation. The substitution of Mg and F ions into the HA crystal structure was confirmed by XPS. Only a limited amount of Mg can be incorporated into HA lattice. The dissolution test revealed that Mg incorporation increased the solubility of the coating in the tris-buffered saline solution. The highest solubility was achieved at x = 1.5 (Ca((10-x))Mg(x)(PO(4))(6) F(OH). In the cell culture test, well-spread cells were observed on all the coatings. Also, a significantly positive effect of Mg ions on cell proliferation and late differentiation was found at x = 1.5. Mg incorporation stimulates osteoblastic cell responses on fluoridated hydroxyapatite coatings.

Identification and consequences of galectin-3 expression in pituitary tumors

Although the mechanisms regulating pituitary tumor development and progression are still unclear, new information on the molecular mechanisms involved in the pathogenesis of human pituitary tumors have accumulated. Recent evidence suggests that galectin-3 plays an important role in pituitary tumorigenesis and in tumor progression. Galectin-3 is expressed in a variety of tumors and the intensity of expression and localization depend on tumor progression, invasiveness and metastatic potential. Galectin-3 expression has been used as a potential diagnostic and/or prognostic marker in a variety of neoplasms. This review summarizes existing information regarding the structural and functional properties of galectin-3 protein as well as the LGALS3 gene in pituitary tumorigenesis. Given its role in pituitary tumor cell proliferation and in apoptosis, galectin-3 may be a target for the treatment of aggressive pituitary tumors.

A two-terminal write-once-read-many-times-memory device based on an aluminum nitride thin film containing Al nanocrystals

A switching from a high-conduction state to a low-conduction state occurs in an AIN thin film containing Al nanocrystals (nc-Al) when the nc-Al is charged with electrons. The switching is explained in terms of breaking of the conductive percolation paths of the nc-AI as a result of the charging of the nc-Al. A write-once-read many times-memory (WORM) device is demonstrated based on this phenomenon. The device can be switched by charging the nc-Al with a voltage of +10 V for 100 ms, yielding a current ratio of the two memory states of more than 300 at the reading voltage of 1 V. The charged state (i.e., the low-conduction state) remains unchanged after more than 1 x 106 read cycles, and its retention time is predicted to be more than 10 years.

Evolution of galanin receptor genes: insights from the deuterostome genomes

Galanin exerts its biological activities through three different G protein-coupled receptors, Galr1, Galr2 and Galr3. To obtain insights into the evolution of Galrs, we searched the genomes of the deuterostomes by extensive BLAST survey and phylogenetic analyses. The Galr2 and Galr3 share similar genomic structures, and most of them are composed of 2 exons and 1 intron. However, most of Galr1 are composed of 3 extrons and 2 introns. We did not detect the typical Galr genes in the genomic databases of invertebrate deutserotomes, but three Galr1/Alstr homologs and two Galr1/Gpr151 homologs in amphioxus, two Galr1/Gpr151 homologs in sea squirt and one Galr1/Gpr151 homologs in sea urchin were identified. It is highly possible that the Galr genes in vertebrates may evolve from the homologous genes of Galr1/Alstr/Gpr151 in invertebrate deuterostomes. We also proposed that Galr3 genes were the products of Galr2 duplication during evolution, while Galr2 genes may evolve from Galr1.

Brain death disrupts structure and function of pig liver

OBJECTIVE

To observe the effects of brain death on hepatic structure and function in pigs and to assess the role of nuclear factor kappaB (NF-kappaB).

MATERIALS AND METHODS

Twelve healthy pigs were randomly allocated to 2 groups of 6 each: a control group with Foley balloon catheter placement intracalvarium only, and a group with brain death established for 24 hours. Serum and hepatic tissue were obtained at 6, 12, and 24 hours after initial confirmation of brain death. Aspartate aminotransferase and alanine aminotransferase concentrations were determined using automated biochemistry analysis. Interleukin-1beta was determined using an enzyme-linked immunosorbent assay. The NF-kappaB messenger RNA was determined using real-time polymerase chain reaction, and NF-kappaB p65 using immunohistochemistry.

RESULTS

Concentrations of aspartate aminotransferase, alanine aminotransferase, and interleukin-1beta in serum, and NF-kappaB messenger RNA and NF-kappaB p65 in hepatic tissue were higher in the brain-dead group compared with the control group, and all increased over time (P<.05).

CONCLUSION

The NF-kappaB activated by brain death promotes synthesis and release of inflammatory mediators, resulting in hepatic dysfunction.

Prognostic factors in survival of colorectal cancer patients with synchronous liver metastasis

AIM

To determine the factors affecting the survival in colorectal cancer patients with synchronous liver metastases.

METHOD

A total of 168 patients who had been treated colorectal cancer with synchronous liver metastases at Guangxi Medical University from January 2000 to December 2005 were identified. Criteria studied consisted of gender, age, time of symptoms, primary tumour location, primary tumour circumference, histological type, grade (tumour differentiation), T-status, N-status, large bowel obstruction, type of operation, primary tumour resection, ascities, location, number and diameter of liver lesions, preoperative CEA and chemotherapy. Survival curves were plotted using the Kaplan-Meier method. Multivariate analysis was conducted by Cox regression analysis.

RESULTS

The mean survival time for all patients was 18.71 (SEM = 1.59) months. The 1, 2, 3 and 5-year survival rates were 55.95%, 23.21%, 12.30%, 8.0% respectively. Univariate analysis share of grade (tumour differentiation), N-status, large bowel obstruction, operation, primary tumour resection, location, number and the most diameter of liver lesions, extrahepatic transfer, preoperative CEA level and chemotherapy to be predictors of survival. In the Cox regression analysis, the N-status, large bowel obstruction, operation, diameter of liver lesion and extrahepatic transfer were independent factors related to survival.

CONCLUSION

Tumour differentiation, N-status, bowel obstruction, operation, primary tumour resection, location of liver metastasis, number of liver metastasis, diameter of liver metastasis, extrahepatic transfer, preoperative CEA level and chemotherapy are related to the survival of patients with colorectal cancer and synchronous liver metastases.

Effectiveness and safety of CEUS-guided haemostatic injection for blunt splenic trauma: an animal experiment

The aim of this study was to investigate whether complications occur after haemostatic agents are injected into blunt splenic injuries. After undergoing ultrasound (US), contrast-enhanced US (CEUS) and contrast-enhanced computed tomography (CECT) examinations, dogs with grade III-IV injury received the minimally invasive therapy. After treatment, CEUS was performed to observe changes in the regions treated. In the immediate group, dogs underwent laparotomy 30 min after treatment to observe the haemostatic effect. In the survival group, animals underwent CEUS and CECT examinations to observe the short-term healing outcome and complications at 3, 7, 14, and 21 days after the injection. After undergoing CEUS and CECT examinations, 12 dogs with grade III-IV injury received the minimally invasive therapy. Before injection, CEUS examinations showed anechoic and/or hypoechoic perfusion defects and active bleeding at the injury sites, and CECT showed traumatic lesions as low-density regions without enhancement. After treatment, CEUS demonstrated the disappearance of active bleeding, and hyperechoic spots emerged at the injury sites. Uneven density regions were displayed on CECT. Treated areas were covered by blood clots and glue membrane in the immediate-group animals. Three weeks later, CEUS showed a decrease of hyperechoic spots in the survival group, and the splenic parenchyma enhanced uniformly on CECT. Laparotomy showed that the greater omentum had moved upwards and partly covered the wound in four animals, and the injury sites had completely healed. Histopathological examination showed that fibrous connective tissue covered the splenic capsule and that the haemostatic glue had degraded. No complication occurred, such as delayed splenic haemorrhage, splenic abscesses, splenic pseudoaneurysms, intestinal obstruction or intestinal adhesions. CEUS-guided haemostatic injection is not only effective in stopping active bleeding immediately, but it is also safe in that no complications occurred during the 3 weeks of follow-up. This study indicates that CEUS-guided percutaneous injection may provide a safe, feasible and effective therapy for blunt splenic trauma.

Higher moments of net proton multiplicity distributions at RHIC

We report the first measurements of the kurtosis (κ), skewness (S), and variance (σ2) of net-proton multiplicity (Np-Np) distributions at midrapidity for Au+Au collisions at square root of s(NN)=19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (μB) between 200 and 20 MeV. Our measurements of the products κσ2 and Sσ, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the square root of s(NN) dependence of κσ2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for μB below 200 MeV.

Three-particle coincidence of the long range pseudorapidity correlation in high energy nucleus-nucleus collisions

We report the first three-particle coincidence measurement in pseudorapidity (Δη) between a high transverse momentum (p⊥) trigger particle and two lower p⊥ associated particles within azimuth |Δϕ|<0.7 in square root of s(NN)=200 GeV d+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range Δη correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured Δη. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

Expansion of mouse sertoli cells on microcarriers

BACKGROUND

Sertoli cells (SCs) have been described as the 'nurse cells' of the testis whose primary function is to provide essential growth factors and create an appropriate environment for development of other cells [for example, germinal and nerve stem cells (NSCs), used here]. However, the greatest challenge at present is that it is difficult to obtain sufficient SCs of normal physiological function for cell transplantation and biological medicine, largely due to traditional static culture parameter difficult to be monitored and scaled up.

OBJECTIVE

Operational stirred culture conditions for in vitro expansion and differentiation of SCs need to be optimized for large-scale culture.

MATERIALS AND METHODS

In this study, the culturing process for primary SC expansion and maintaining lack of differentiation was optimized for the first time, by using microcarrier bead technology in spinner flask culture. Effects of various feeding/refreshing regimes, stirring speeds, seed inoculum levels of SCs, and concentrations of microcarrier used for expansion of mouse SCs were also explored. In addition, pH, osmotic pressure and metabolic variables including consumption rates of glucose, glutamine, amino acids, and formation rates of lactic acid and ammonia, were investigated in culture.

RESULTS

After 6 days, maximal cell densities achieved were 4.6 x 10(6) cells/ml for Cytodex-1 in DMEM/FBS compared to 4.8 x 10(5) cells/ml in static culture. Improved expansion was achieved using an inoculum of 1 x 10(5) cells/ml and microcarrier concentration of 3 mg/ml at stirring speed of 30 rpm. RESULTS indicated that medium replacement (50% changed everyday) resulted in supply of nutrients and removal of waste products inhibiting cell growth, that lead to maintenance of cultures in steady state for several days. These conditions favoured preservation of SCs in the undifferentiated state and significantly increased their physiological activity and trophic function, which were assessed by co-culturing with NSCs and immunostaining.

CONCLUSION

Data obtained in this study demonstrate the vast potential of this stirred culture system for efficient, reproducible and cost-effective expansion of SCs in vitro. The system has advantages over static culture, which has major obstacles such as lower cell density, is time-consuming and susceptible to contamination.

A comparison of oxygenation methods fro high-density perfusion culture of animal cells

A perfusion culture system was developed to investigate the oxygenation of high-density hybridoma cell cultures. The culture system was composed of a stirred-tank bioreactor and an external microfiltration hollow fiber cartridge for medium perfusion. Cell growth and antibody production were examined with large bubble ( approximately 5 mm in diameter), micron-sized bubble ( approximately 80 mum in diameter), and silicone tubing oxygenation techniques. Comparable cell growth and monoclonal antibody (MAb) production were found for both the micron-sized and large oxygenation methods, provided that large bubbles were enriched with pure oxygen. Relatively low cell growth and MAb production were attained with the bubble-free silicone tubing oxygenation. It is concluded that direct bubble oxygenation can be applied successfully in high-density animal cell cultures, provided that the culture medium is supplemented with Pluronic F-68. The accumulation of ammonia in the culture medium rather than oxygen limitation was found to be one of the possible problems that eventually inhibited cell growth. This and the fouling of the filtration cartridge during long-term cultivation were found to be more problematic than simple bubble oxygenation of high-density cell culture. The micron-sized bubble oxygenation method is highly recommended for high-density animal cell cultures, provided that Pluronic F-68 is supplemented into the culture medium.