Above-bandgap voltages from ferroelectric photovoltaic devices

In conventional solid-state photovoltaics, electron-hole pairs are created by light absorption in a semiconductor and separated by the electric field spaning a micrometre-thick depletion region. The maximum voltage these devices can produce is equal to the semiconductor electronic bandgap. Here, we report the discovery of a fundamentally different mechanism for photovoltaic charge separation, which operates over a distance of 1-2 nm and produces voltages that are significantly higher than the bandgap. The separation happens at previously unobserved nanoscale steps of the electrostatic potential that naturally occur at ferroelectric domain walls in the complex oxide BiFeO(3). Electric-field control over domain structure allows the photovoltaic effect to be reversed in polarity or turned off. This new degree of control, and the high voltages produced, may find application in optoelectronic devices.

Studies on long-term infection of human cells with Porcine endogenous retrovirus

A major concern in pig-to-human xenotransplantations is the potential risk of transmission of Porcine endogenous retroviruses (PERVs) integrated in the pig genome. Our previous work has shown that PERV provirus genes and gag protein can be detected in human embryonic kidney HEK-293 cells during a long-term infection with PERV (Yu et al., Transplant. Proc. 37, 496-499, 2005). In this study, we continued studying the long-term (>6 months) PERV infection of HEK-293 cells. The results showed no significant differences in morphology, growth, apoptosis, and [(3)H]-thymidine incorporation between PERV-infected and uninfected cells. The PERV LTR sequence showed only an insignifcant mutation after the long-term infection. PERV infection had no effect on the transcription of genes of Human endogenous retrovirus (HERV) naturally occurring in HEK-293 cells. Summing up, this study indicated that a long-term PERV infection of HEK-293 cells in vitro does not result in any significant changes in host cells as well as in PERV LTR sequence.

Safety profile of dexlansoprazole MR, a proton pump inhibitor with a novel dual delayed release formulation: global clinical trial experience

BACKGROUND

Dexlansoprazole MR is a dual delayed release formulation of dexlansoprazole, an enantiomer of lansoprazole.

AIM

To assess safety of dexlansoprazole MR in phase 3 clinical trials.

METHODS

Data from 4270 patients receiving dexlansoprazole MR 30 mg (n = 455), 60 mg (n = 2311) or 90 mg (n = 1864); lansoprazole 30 mg (n = 1363); or placebo (n = 896) in six randomized controlled trials and a 12-month safety study were pooled. Safety was assessed via adverse events, vital signs, electrocardiograms, clinical laboratory results and gastric biopsies. Adverse events were summarized per 100 patient-months of exposure to account for imbalances in study drug exposure.

RESULTS

The number of patients with > or =1 treatment-emergent adverse event per 100 patient-months was higher in placebo (24.49) and lansoprazole (21.06) groups than in any dexlansoprazole MR (15.64-18.75) group. Fewer patients receiving dexlansoprazole MR discontinued therapy because of an adverse event (P < or = 0.05 vs. placebo). Seven patients died of events considered unrelated to study drug. Mean serum gastrin rose in all groups except placebo; increases were not dose-related. No clinically concerning trends were seen in gastric biopsy results. Endocrine cell hyperplasia, dysplasia and neoplasia were not observed.

CONCLUSION

Dexlansoprazole MR 30-90 mg has a safety profile comparable to that of lansoprazole.

Role of hepcidin in murine brain iron metabolism

Brain iron homeostasis is maintained by a balance of both iron uptake and release, and accumulating evidence has revealed that brain iron concentrations increase with aging. Hepcidin, an iron regulatory hormone produced by hepatocytes in response to inflammatory stimuli, iron, and hypoxia, has been shown to be the long-sought hormone responsible for the regulation of body iron balance and recycling in mammals. In this study, we report that hepcidin is widely expressed in the murine brain. In cerebral cortex, hippocampus and striatum, hepcidin mRNA levels increased with aging. Injection of hepcidin into the lateral cerebral ventricle resulted in decreased Fpn1 protein levels in cerebral cortex, hippocampus, and striatum. Additionally, treatment of primary cultured neurons with hepcidin caused decreased neuronal iron release and Fpn1 protein levels. Together, our data provide further evidence that hepcidin may be involved in the regulation of brain iron metabolism.

Heat-induced protein structure and subfractions in relation to protein degradation kinetics and intestinal availability in dairy cattle

The objectives of this study were to reveal protein structures of feed tissues affected by heat processing at a cellular level, using the synchrotron-based Fourier transform infrared microspectroscopy as a novel approach, and quantify protein structure in relation to protein digestive kinetics and nutritive value in the rumen and intestine in dairy cattle. The parameters assessed included 1) protein structure alpha-helix to beta-sheet ratio; 2) protein subfractions profiles; 3) protein degradation kinetics and effective degradability; 4) predicted nutrient supply using the intestinally absorbed protein supply (DVE)/degraded protein balance (OEB) system for dairy cattle. In this study, Vimy flaxseed protein was used as a model feed protein and was autoclave-heated at 120 degrees C for 20, 40, and 60 min in treatments T1, T2, and T3, respectively. The results showed that using the synchrotron-based Fourier transform infrared microspectroscopy revealed and identified the heat-induced protein structure changes. Heating at 120 degrees C for 40 and 60 min increased the protein structure alpha-helix to beta-sheet ratio. There were linear effects of heating time on the ratio. The heating also changed chemical profiles, which showed soluble CP decreased upon heating with concomitant increases in nonprotein nitrogen, neutral, and acid detergent insoluble nitrogen. The protein subfractions with the greatest changes were PB1, which showed a dramatic reduction, and PB2, which showed a dramatic increase, demonstrating a decrease in overall protein degradability. In situ results showed a reduction in rumen-degradable protein and in rumen-degradable dry matter without differences between the treatments. Intestinal digestibility, determined using a 3-step in vitro procedure, showed no changes to rumen undegradable protein. Modeling results showed that heating increased total intestinally absorbable protein (feed DVE value) and decreased degraded protein balance (feed OEB value), but there were no differences between the treatments. There was a linear effect of heating time on the DVE and a cubic effect on the OEB value. Our results showed that heating changed chemical profiles, protein structure alpha-helix to beta-sheet ratio, and protein subfractions; decreased rumen-degradable protein and rumen-degradable dry matter; and increased potential nutrient supply to dairy cattle. The protein structure alpha-helix to beta-sheet ratio had a significant positive correlation with total intestinally absorbed protein supply and negative correlation with degraded protein balance.

Electric modulation of conduction in multiferroic Ca-doped BiFeO3 films

Many interesting materials phenomena such as the emergence of high-Tc superconductivity in the cuprates and colossal magnetoresistance in the manganites arise out of a doping-driven competition between energetically similar ground states. Doped multiferroics present a tantalizing evolution of this generic concept of phase competition. Here, we present the observation of an electronic conductor-insulator transition by control of band-filling in the model antiferromagnetic ferroelectric BiFeO3 through Ca doping. Application of electric field enables us to control and manipulate this electronic transition to the extent that a p-n junction can be created, erased and inverted in this material. A 'dome-like' feature in the doping dependence of the ferroelectric transition is observed around a Ca concentration of approximately 1/8, where a new pseudo-tetragonal phase appears and the electric modulation of conduction is optimized. Possible mechanisms for the observed effects are discussed on the basis of the interplay of ionic and electronic conduction. This observation opens the door to merging magnetoelectrics and magnetoelectronics at room temperature by combining electronic conduction with electric and magnetic degrees of freedom already present in the multiferroic BiFeO3.

Relationship and prognosis of hospho-Akt and CD44v6 in breast cancer

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Background: The purpose of this study was to investigate the relationship between pAkt and CD44v6 expression of breast cancer after surgery. We also evaluated the expression patterns and predictive value of pAKT and CD44v6 in breast cancer tissues. Methods: Expression of pAkt and CD44v6 protein was detected using immunohistochemistry in 98 patients. The correlation between the expression of pAkt, CD44v6, and other disease-related characteristics with treatment outcome was investigated. Kaplan-Meier survival analysis and Cox regression were used to observe the correlation between variables and the prognostic value. Results: Of all these 98 cases, 37 cases (37.8%) were observed as positive for pAkt expression, and there were 25 cases (51.0%) pAKT positive expression in the lymph node (+) and 15 (30.6%) in lymph node (-) of 49 cases. pAkt expression had no significant difference in node-positive group and node-negative group. We examined the relationship between pAKT and HER2 expression, pAkt expression was positively correlated with HER-2 expression (p = 0.009). A statistically significant difference in positive staining for pAkt was observed between CD44V6-positive and CD44V6-negative tumors (p = 0.016). CD44v6 positive tumors showed a statistically very highly significant association between node-positive and node-negative (p = 0.013). For prognosis value, a week relationship was observed between pAkt and OS, but DFS was inversely associated with pAkt staining intensity (p = 0.061, p = 0.004). There had a statistical correlation between CD44v6 overexpression and OS and DFS (p = 0.026 and 0.006 respectively). Univariate analysis revealed that lymph node status and CD44V6 were significantly associated with decreased OS and DFS, but there had no significant difference between variables and OS and DFS by multivariate analysis. Conclusions: Our data suggested that there had a intensive relationship between pAKT and CD44v6 expression in breast cancer tissues. We demonstrated that both pAkt and CD44v6 were significantly assiociated with a decreased OS and DFS in breast cancer patients. pAKT and CD44v6 overexpressed in cancer cells may be sensitive markers for predicting the treatment outcome in breast cancer patients.

No significant financial relationships to disclose.

Observation of ferromagnetic resonance in SrRuO3 by the time-resolved magneto-optical Kerr effect

We report the observation of ferromagnetic resonance (FMR) in SrRuO3 using the time-resolved magneto-optical Kerr effect. The FMR oscillations in the time-domain appear in response to a sudden, optically induced change in the direction of easy-axis anisotropy. The high FMR frequency, 250 GHz, and large Gilbert damping parameter, alpha approximately 1, are consistent with strong spin-orbit coupling. We find that the parameters associated with the magnetization dynamics, including alpha, have a nonmonotonic temperature dependence, suggestive of a link to the anomalous Hall effect.

Conduction at domain walls in oxide multiferroics

Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO(3). The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features.

Understanding the differences in molecular conformation of carbohydrate and protein in endosperm tissues of grains with different biodegradation kinetics using advanced synchrotron technology

Conventional "wet" chemical analyses rely heavily on the use of harsh chemicals and derivatization, thereby altering native seed structures leaving them unable to detect any original inherent structures within an intact tissue sample. A synchrotron is a giant particle accelerator that turns electrons into light (million times brighter than sunlight) which can be used to study the structure of materials at the molecular level. Synchrotron radiation-based Fourier transform IR microspectroscopy (SR-FTIRM) has been developed as a rapid, direct, non-destructive and bioanalytical technique. This technique, taking advantage of the brightness of synchrotron light and a small effective source size, is capable of exploring the molecular chemistry within the microstructures of a biological tissue without the destruction of inherent structures at ultraspatial resolutions within cellular dimensions. This is in contrast to traditional 'wet' chemical methods, which, during processing for analysis, often result in the destruction of the intrinsic structures of feeds. To date there has been very little application of this technique to the study of plant seed tissue in relation to nutrient utilization. The objective of this study was to use novel synchrotron radiation-based technology (SR-FTIRM) to identify the differences in the molecular chemistry and conformation of carbohydrate and protein in various plant seed endosperms within intact tissues at cellular and subcellular level from grains with different biodegradation kinetics. Barley grain (cv. Harrington) with a high rate (31.3%/h) and extent (78%), corn grain (cv. Pioneer) with a low rate (9.6%/h) and extent of (57%), and wheat grain (cv. AC Barrie) with an intermediate rate (23%/h) and extent (72%) of ruminal DM degradation were selected for evaluation. SR-FTIRM evaluations were performed at the National Synchrotron Light Source at the Brookhaven National Laboratory (Brookhaven, NY). The molecular structure spectral analysis involved the fingerprint regions of ca. 1720-1485 cm(-1) (attributed to protein amide I C=O and C-N stretching; amide II N-H bending and C-N stretching), ca. 1650-950 cm(-1) (non-structural CHO starch in endosperms), and ca. 1185-800 cm(-1) (attributed to total CHO C-O stretching vibrations) together with agglomerative hierarchical cluster and principal component analyses. Analyses involving the protein amide I features consistently identified differences between all three grains. Other analyses involving carbohydrate features were able to differentiate between wheat and barley but failed however to differentiate between wheat and corn. These results suggest that SR-FTIRM plus the multivariate analyses can be used to identify spectral features associated with the molecular structure of endosperm from grains with different biodegradation kinetics, especially in relation to protein structure. The Novel synchrotron radiation-based bioanalytical technique provides a new approach for plant seed structural molecular studies at ultraspatial resolution and within intact tissue in relation to nutrient availability.

Genetic structure of Oryza rufipogon Griff. in China

Oryza rufipogon Griff. (common wild rice; CWR) is the ancestor of Asian cultivated rice (Oryza sativa L.). Investigation of the genetic structure and diversity of CWR in China will provide information about the origin of cultivated rice and the grain quality and yield. In this study, we used 36 simple sequence repeat (SSR) markers to assay 889 accessions, which were highly representative of whole germplasm in China. The analysis revealed a hierarchical genetic structure within CWR. First, CWR has diverged into two ecotypic populations, a south subtropical population (SSP) and a middle subtropical population (MSP), probably owing to natural selection by the different climates. The distribution of specific alleles and haplotypes indicated that Chinese CWR had both indica-like and japonica-like variations; the SSP was an indica-like type, whereas the MSP was more japonica-like. The SSP and MSP further diverged into five (HN, GD-GX1, GX2, FJ and YN) and two (JX-HuN1 and HuN2) geographical populations, respectively. The genetic data suggest the isolation by distance, although water systems also appear to play an important role in the formation of homogenous populations, and occasionally landscape was also involved. The population GD-GX1, which grew widely in Guangdong and Guangxi provinces, was the largest geographical population in China. It had a high level of genetic diversity (GD) and the closest genetic relationship with other inferred populations. The population HN, with the smallest SSR molecular weights and the highest level of GD, may be the most ancestral population.

Protein value of a new genotype oat (CDC SO-I) for the NRC dairy model: Protein degradation balance and kinetics, protein fractions and total metabolizable protein supply

Recently, a new genotype of oat has been developed specifically for feed purposes by the Crop Development Centre called CDC SO-I (“SuperOat”) containing a low-lignin hull and a high-fat groat. However, no quantitative evaluation of protein supply from CDC SO-I to dairy cow has been done in terms of potential protein degradation balance (PDB) and total metabolizable protein (MP) supply. These data are crucial in order to develop more efficient, competitive and optimal feeding the new genotype of oat (CDC SO-I) for livestock. Unlike DVE/OEB, PBI, ARC and NKJ-NJF models, NRC-2001 is a total digestible nutrient (TDN-) based model which is more popular in North America. The objectives of this study were to use the NRC model with inputs based on laboratory and in situ techniques to predict the potential nutrient supply to dairy cows from CDC SO-I in comparison with two conventional oat varieties, CDC Dancer and Derby, in western Canada. The quantitative predictions were made in terms of: (1) Rumen-synthesized microbial protein truly absorbed in the small intestine (AMCP); (2) Rumen undegraded feed protein truly absorbed in the small intestine (ARUP); (3) Endogenous protein in the digestive tract (AECP); (4) Total metabolizable protein supply in the small intestine (MP), and (5) Protein degraded balance (PDB). The results show that using the NRC model, the predicted PDB and total MP supplies to dairy cattle were significantly increased from the newly developed genotype of oat (CDC SO-I). Compared with the normal oat, CDC Dancer, CDC SO-I significantly increased (P < 0.05) ARUP, by 24%, and total MP supply by 9%, but did not change (P > 0.05) AMCP, AECP and PDB, with averages of 55.7, 4.5 and -11.96 g kg-1 dry matter (DM), respectively. Compared with the normal variety, Derby, CDC SO-I significantly increased (P < 0.05) AMCP, by 19%, total MP supply by 13% and increased PDB by 114%, but did not change (P > 0.05) ARUP and AECP values with averages of 19.2 and 4.5 g kg-1 DM, respectively. In conclusion, CDC SO-I oat increased total absorbed metabolizable protein supply to dairy cattle by 9–13% in comparison with the two conventional oat varieties used in western Canada. However, although CDC SO-I improved protein degraded balance, it still had a negative value (-10.6 g kg-1 DM), indicating the potential imbalance between microbial protein synthesis from available rumen-degradable crude protein (CP) and potential energy from fermentation in the rumen. Key words: TDN-based model, dairy cattle, oat genotype, protein degradation balance, metabolizable protein supply

Beta2-glycoprotein I inhibits vascular endothelial growth factor and basic fibroblast growth factor induced angiogenesis through its amino terminal domain

BACKGROUND

Beta-2 glycoprotein I (beta(2)GPI) is a plasma glycoprotein which interacts with various proteins of the coagulation and fibrinolysis system. beta(2)GPI has recently been shown to have anti-angiogenic properties.

OBJECTIVES

We undertook this study to investigate the specific domain of beta(2)GPI involved in the anti-angiogenic function and its effect on downstream signaling of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF).

METHODS

Various preparations of beta(2)GPI were used on human umbilical vein endothelial cells (HUVECs) in the absence or presence of VEGF and bFGF. The effect on HUVECs' proliferation, migration and tubule formation in Matrigel matrix was investigated. The effect of beta(2)GPI on the mRNA expression of VEGF receptors and phosphorylation of signaling molecules was also studied.

RESULTS

beta(2)GPI is shown in this study to be an anti-angiogenic molecule in vitro by inhibiting VEGF and bFGF-induced proliferation, migration and papillary-like tubule formation of HUVECs. This inhibition was achieved by native, proteolytically clipped and domain deletion mutants, domain I-IV (DI-IV) but not domain II-V (DII-V) of beta(2)GPI. Native beta(2)GPI was found to downregulate the expression of the VEGF receptor KDR/Flk-1 on endothelial cells and to block the phosphorylation of VEGF's downstream effector molecules in the MAPK/ERK and PI3K/Akt/GSK3beta pathways.

CONCLUSIONS

These results indicate that beta(2)GPI has anti-angiogenic functions which depend on the presence of domain I. This anti-angiogenic activity may have important implications for the therapeutic manipulation of angiogenesis in various disease states.

Transmission of porcine endogenous retrovirus to human cells in nude mouse

Xenotransplantation is associated with the risk of Porcine endogenous retrovirus (PERV) transmission, since it has been shown that PERV can infect human cells in vitro (Specke et al., Virology 285, 177-180, 2001). We evaluated the possibility of PERV infection of human cells in nude mice model. Porcine kidney cells PK15 carrying PERV and human liver cancer cells SMMC-7721 were injected separately into the right and left axilla of nude mice, respectively. Two months later, pig cytochrome oxidase II (COII) gene, PERV DNA, PERV mRNA, and PERV-Gag protein were detected in the mass formed in both axillas and in several organs of nude mice. The pig COII genes were detected in the right and left axilla, but not in other organs of nude mice implicating that the microchimerism of pig cells occurred in human SMMC-7721 cells and induced the formation of the mass. PERV gene and gag protein were detected in all mouse tissues except liver. These data indicated that (i) PERV may be transmitted from porcine to mouse cells, (ii) PERV genes and proteins were detectable in the mass formed by injection of human cells and consequently (iii) there was a possibility of PERV transmission to human cells after xenotransplantation.