First Report of Rust of Plumeria rubra Caused by Coleosporium plumeriae in Guangdong Province, China

Plumeria spp. are ornamental trees commonly planted in parks and gardens, and Plumeria rubra cultivars (Frangipani) is most common in Guangdong Province, China. A rust disease of P. rubra was observed on leaves of susceptible plants from August to December 2013. Ten nurseries were surveyed in September 2013, and 91% (220 of 240) of the plumeria plants were infected with rust. Symptoms first appeared as chlorotic spots (about 1 mm in diameter) appearing on adaxial leaf surfaces and then spread to whole leaf, and infection further resulted in leaf necrosis and abscission. Therefore, the ornamental value of diseased trees was greatly diminished. Bright yellow or yellow-orange uredinia were hypophyllous and produced under the epidermis. Urediniospores were catenulate, globose, ovoid or ellipsoid, and sometimes angular in appearance, ranging from 20.0 to 42.0 μm in length by 14.1 to 25.6 μm in width. Their walls were verrucose and 1.3 to 3.2 μm thick. No teliospores were observed. The rust was identified as Coleosporium plumeriae Pat. based on urediniospore morphology (2). Species identity was confirmed with a 1,551-bp sequence (GenBank Accession No. KF879087) of ITS rDNA amplified with rust-specific primers Rust2inv and LR6 (1). The amplicon had a 100% similarity to C. plumeriae (GU145555). Pathogenicity was confirmed by spraying a urediniospores suspension (15,000 spores ml^-1) on five plants of P. rubra cultivar. Five leaves of each plant were inoculated and sealed in plastic bags, while five control plants were applied with sterile water. Plants were held at 28°C for 36 h in a dew chamber. All inoculated leaves developed typical rust symptoms with the uredinia appearing after 9 days, no symptoms developed on any control plants. Urediniospores were produced on infected leaves and pathogen identity was confirmed by morphology and re-sequencing of the ITS rDNA. Plumeria rust was first found in Hong Kong (4) and then in Hainan and Yunnan Provinces, China (3). However, this is the first report of plumeria rust in Guangdong Province, China. Frangipani has large, colorful flowers in the summer, and this rapidly spreading disease causes severe damage and affects their aesthetic value in the second half of the year. References: (1) M. C. Aime. Mycoscience 47:112, 2006. (2) N. Patouillard. Bull. Soc. Mycol. Fr. 18:171, 1902. (3) Q. Wang et al. New Dis. Rep. 23, doi:10.5197/j.2044-0588.2011.023.010, 2011. (4) J. Yan et al. Mycosystema 25:327, 2006 (in Chinese).

Association of the tumour necrosis factor-α polymorphisms rs361525 and rs1800629 with susceptibility to psoriasis: a meta-analysis

BACKGROUND

Evidence has suggested that tumour necrosis factor (TNF)-α may be involved in the aetiology of psoriasis, but the underlying association of the TNF-α polymorphisms -238G/A (rs361525) and -308G/A (rs1800629) with the risk of psoriasis is still unconfirmed.

AIM

This meta-analysis was performed to determine whether the TNF-α -238G/A and -308G/A polymorphisms are associated with susceptibility to psoriasis.

METHODS

Eligible studies were identified by searching PubMed, EMBASE, CNKI (China National Knowledge Infrastructure), CBM (Chinese biomedical literature database) and WANFANG databases within a range of published years from 1990 to August 2012. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the different associations.

RESULTS

In total, 17 studies with 2847 cases and 2222 controls were found for -238G/A and 20 studies with 2975 cases and 2243 controls for -308G/A. The pooled results showed an overall increased risk of psoriasis for the -238G/A polymorphism (OR = 2.06, 95% CI = 1.45-2.94, P < 0.001 for AA/GA vs. GG) and a reduced psoriasis risk with the -308G/A polymorphism (OR = 0.68, 95% CI = 0.59-0.79, P < 0.001 for AA/GA vs. GG). This association was only present in early-onset psoriasis (OR = 3.68, 95% CI = 2.17-6.24, P < 0.001 for -238G/A; OR = 0.56, 95% CI = 0.43-0.72, P < 0.001 for -308G/A), whereas there was no association (OR = 0.98, 95% CI = 0.56-1.70, P = 0.92 for -238G/A) or a unreliable association (OR = 0.66, 95% CI = 0.46-0.94, P = 0.02 for -308G/A) in late-onset psoriasis.

CONCLUSIONS

This meta-analysis suggests that the TNF-α -238 and -308 promoter polymorphisms may play different roles in conferring susceptibility to psoriasis. Functional and well-designed studies should be conducted to confirm these results.

Effect of strain on voltage-controlled magnetism in BiFeO₃-based heterostructures

Voltage-modulated magnetism in magnetic/BiFeO₃ heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO₃ and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO₃ film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO₃ that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO₃-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO₃-based heterostructures.

Virtual screening methods as tools for drug lead discovery from large chemical libraries

Virtual screening methods have been developed and explored as useful tools for searching drug lead compounds from chemical libraries, including large libraries that have become publically available. In this review, we discussed the new developments in exploring virtual screening methods for enhanced performance in searching large chemical libraries, their applications in screening libraries of ~ 1 million or more compounds in the last five years, the difficulties in their applications, and the strategies for further improving these methods.

Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts

The aim of this study was to evaluate the susceptibility of 43 strains of lactic acid bacteria, isolated from Chinese yogurts made in different geographical areas, to 11 antibiotics (ampicillin, penicillin G, roxithromycin, chloramphenicol, tetracycline, chlortetracycline, lincomycin, kanamycin, streptomycin, neomycin, and gentamycin). The 43 isolates (18 Lactobacillus bulgaricus and 25 Streptococcus thermophilus) were identified at species level and were typed by random amplified polymorphic DNA analysis. Thirty-five genotypically different strains were detected and their antimicrobial resistance to 11 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, chloramphenicol, chlortetracycline, tetracyclines, lincomycin, streptomycin, neomycin, and gentamycin was found among the 35 strains tested. All of the Strep. thermophilus strains tested were susceptible to penicillin G and roxithromycin, whereas 23.5 and 64.7% of Lb. bulgaricus strains, respectively, were resistant. All of the Strep. thermophilus and Lb. bulgaricus strains were found to be resistant to kanamycin. The presence of the corresponding resistance genes in the resistant isolates was investigated through PCR, with the following genes detected: tet(M) in 1 Lb. bulgaricus and 2 Strep. thermophilus isolates, ant(6) in 2 Lb. bulgaricus and 2 Strep. thermophilus isolates, and aph(3')-IIIa in 5 Lb. bulgaricus and 2 Strep. thermophilus isolates. The main threat associated with these bacteria is that they may transfer resistance genes to pathogenic bacteria, which has been a major cause of concern to human and animal health. To our knowledge, the aph(3')-IIIa and ant(6) genes were found in Lb. bulgaricus and Strep. thermophilus for the first time. Further investigations are required to analyze whether the genes identified in Lb. bulgaricus and Strep. thermophilus isolates might be horizontally transferred to other species.

First Report of Bacterial Soft Rot on Tagetes patula Caused by Dickeya dieffenbachiae in China

French marigold (Tagetes patula L.), originally from Mexico, is an annual herb widely planted in China because of its beautiful color, long flowering, and strong adaptability, and has been used widely for ornamentation and decorating. French marigold is also rich in patuletin, quercetagetin, and patulitrin, and is therefore applied medicinally for treating colds and coughs. In early summer 2012, soft rot symptoms on French marigold were found at three flower nurseries in Guangzhou, Guangdong Province, P. R. China, and approximately 25% of the plants had the symptoms. The symptoms included tissue collapse of the stems at the soil line followed by wilting of the whole plants. Within 1 week, the infected stems showed vascular discoloration, turned brown and then inky black, and eventually the whole plant collapsed after the basal stem was infected. Bacteria were successfully isolated from eight symptomatic plants on nutrient agar media incubated at 30°C for 48 h. Ten isolates were selected randomly for further characterization. They were gram negative, degraded pectate, negative for oxidase and positive for indole production, and utilized malonate, glucose, and sucrose but not glucopyranoside, trehalose, or palatinose. Polymerase chain reactions (PCR) were performed using the 16S primers 27f and 1495r (4) for molecular identification. Subsequent DNA sequencing showed that the representative tested strain TP1 (GenBank Accession No. JX575747) was 99% identical to that of Dickeya dieffenbachiae (JF419463) using BLASTn. Further genetic analysis of strain TP1 was performed targeting several housekeeping genes, i.e., dnaX (GenBank Accession No. JX575748) with primers dnaxf and dnaxr (3), gyrB (JX575749) with primers of gyrbf1 and gyrbr1 (1), and gapA (JX575750) with primers of gapa326f and gapa845r (2). They were most homologous to the sequences of D. dieffenbachiae, since they had 97%, 96%, and 97% identity with GenBank accessions GQ904794, JF311653, and GQ891968, respectively. Pathogenicity was confirmed by injecting all 10 original bacterial isolates into each of 10 French marigold seedlings, with approximately 100 μl of a bacterial suspension at 1 × 108 CFU/ml. Ten plants inoculated with 100 μl of sterile water served as controls. Plants were placed in a greenhouse at 30 to 32°C and 90% relative humidity. Within 48 h, soft rot symptoms appeared on all inoculated seedlings, while the control plants appeared normal. D. dieffenbachiae was reisolated from the diseased tissues, and confirmed to be the same as the inoculated pathogen by conducting a 16S rDNA sequence comparison. Previously, black spot, botrytis blight, oedema, powdery mildew, southern bacterial wilt, and damping off have been found on T. patula. To our knowledge, it is the first report of a soft rot caused by D. dieffenbachiae on French marigold. Because of the popularity and high economic value of French marigold, identification of this progressing bacterial disease is important to maintain safe production and beautiful scenery. References: (1) B. R. Lin et al. Plant Dis. 96:452, 2012. (2) S. Nabhan et al. Plant Pathol. 61:498, 2012. (3) M. Sławiak et al. Eur. J. Plant Pathol. 125:245, 2009. (4) W. G. Weisburg. J. Bacteriol. 173:697, 1991.

Kinetic, isotherm and thermodynamic studies of the adsorption of crystal violet by activated carbon from peanut shells

The adsorption of crystal violet dye from aqueous solutions onto an activated carbon prepared from peanut shells was analyzed in this study. The effects of particle size, initial concentration, time and temperature on crystal violet removal were studied in batch experiments. Experimental results showed that the adsorption equilibrium was achieved within 100 min for all studied concentrations. Analysis of adsorption results showed that the adsorption isotherms could be well fitted to the Langmuir model. Kinetic parameters, rate constants, equilibrium adsorption capacities and related correlation coefficients for pseudo first-order and second-order kinetic models were calculated and discussed. The results revealed that the adsorption kinetics was in good agreement with the pseudo second-order equation. Thermodynamic parameters such as the change of Gibbs free energy (ΔG°), change of enthalpy (ΔH°) and change of entropy (ΔS°) have also been determined and it has been found that the adsorption process should be spontaneous, endothermic and physisorption in nature.

First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. carotovorum in Guangdong Province of China

Potato (Solanum tuberosum L.) is a major crop in China, with 80.0 million tons being produced in 2010 on 3.3 million ha. Pectobacterium carotovorum subsp. carotovorum Jones 1901; Hauben et al. 1999 causes soft rot worldwide on a wide range of hosts including potato, carrot, and cabbage. During spring 2010, a soft rot with a foul smell was noted in stored potato tubers of different cultivars in the Guangdong Province. Symptoms on tubers appeared as tan, water-soaked areas with watery ooze. The rotted tissues were white to cream colored. Stems of infected plants with typical inky black symptoms could also be found in the fields prior to harvest. Three different potato fields were surveyed, and 13% of the plants had the symptoms. Twenty-seven samples (three symptomatic tubers per sample) were collected. Bacteria were successfully isolated from all diseased tissues on nutrient agar media supplemented with 5% sucrose and incubated at 26 ± 1°C for 36 h. After purification on tripticase soy agar media, four typical strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) were identified using the following deterministic tests: gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, sensitive to erythromycin, negative for phosphatase, unable to produce acid from α-methyl-glucoside, and produced acid from trehalose. Biolog analysis (Ver 4.20.05, Hayward, CA) identified the strains as P. carotovorum subsp. carotovorum (SIM 0.808, 0.774, 0.782, and 0.786, respectively). The identity of strains 7-3-1 (GenBank Accession No. JX258132), 7-3-2 (JX258133), and 8-3-1 (JX196705) was confirmed by 16S rRNA gene sequencing (4), since they had 99% sequence identity with other P. carotovorum subsp. carotovorum strains (GenBank Accession Nos. JF926744 and JF926758) using BLASTn. Further genetic analysis of strain 8-3-1 was performed targeting informative housekeeping genes, i.e., acnA (GenBank Accession No. JX196704), gabA (JX196706), icdA (JX196707), mdh (JX196708), mtlD (JX196709), pgi (JX196710), and proA (JX196711) (2). These sequences from strain 8-3-1 were 99 to 100%, homologous to sequences of multiple strains of P. carotovorum subsp. carotovorum. Therefore, strain 8-3-1 grouped with P. carotovorum subsp. carotovorum on the phylogenetic trees (neighbor-joining method, 1,000 bootstrap values) of seven concatenated housekeeping genes when compared with 60 other strains, including Pectobacterium spp. and Dickeya spp. (3). Pathogenicity of four strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) was evaluated by depositing a bacterial suspension (10⁶ CFU/ml) on the potato slices of cultivar 'Favorita' and incubating at 30 ± 1°C. Slices inoculated with just water served as non-inoculated checks. The strains caused soft rot within 72 h and the checks had no rot. Bacteria were reisolated from the slices and were shown to be identical to the original strains based on morphological, cultural, and biochemical tests. Although this pathogen has already been reported in northern China (1), to our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of potato in Guangdong Province of China. References: (1) Y. X. Fei et al. J. Hexi Univ. 26:51, 2010.(2) B. Ma et al. Phytobacteriology 97:1150, 2007. (3) S. Nabhan et al. Plant Pathol. 61:498, 2012. (4) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

Nanoscale phase boundaries: a new twist to novel functionalities

In functional materials, nanoscale phase boundaries exhibit exotic phenomena that are notably absent in their parent phases. Over the past two decades, much of the research into complex oxides (such as cuprate superconductors, CMR manganites and relaxor ferroelectrics) has demonstrated the key role that nanoscale inhomogeneities play in controlling the electronic and/or ionic structure of these materials. One of the key characteristics in such systems is the strong susceptibility to external perturbations, such as magnetic, electric and mechanical fields. A direct consequence of the accommodation of a large number of cationic substitutions in complex oxides is the emergence of a number of physical phenomena from essentially the same crystal framework. Recently, multiferroic behavior, which is characterized by the co-existence and potential coupling of multiple ferroic order parameters, has captured considerable worldwide research interest. The perovskite, BiFeO(3), exhibits robust ferroelectricity coupled with antiferromagnetism at room temperature. A rather unique feature of this material system is its ability to "morph" its ground state when an external mechanical constraint is imposed on it. A particularly striking example is observed when a large (~4 to 5%) compressive strain is imposed on a thin film through the epitaxial constraint from the underlying substrate. Under these conditions, the ground state rhombohedral phase transforms into a tetragonal-like (or a derivative thereof) phase with a rather large unit cell (c/a ratio of ~1.26). When the epitaxial constraint is partially relaxed by increasing the film thickness, this tetragonal-like phase evolves into a "mixed-phase" state, consisting of a nanoscale admixture of the rhombohedral-like phase embedded in the tetragonal-like phase. Such a system gives us a new pathway to explore a variety of mechanical, magnetic and transport phenomena in constrained dimensions. This article reviews our progress to date in this direction and also captures some possible areas of future research. We use the electromechanical response and the magnetic properties as examples to illustrate that its novel functionalities are intrinsically due to the phase boundaries and not the constituent phases. The possible origin of the giant piezoelectric response and enhanced magnetic moment across the boundaries is proposed based on the flexoelectric and flexomagnetic effects.

Identification of direct forkhead box O1 targets involved in palmitate-induced apoptosis in clonal insulin-secreting cells using chromatin immunoprecipitation coupled to DNA selection and ligation

AIMS/HYPOTHESIS

The transcription factor, forkhead box (FOX)O1, is involved in fatty acid-induced apoptosis in pancreatic beta cells, but the precise mechanism is poorly understood. We aimed to identify which direct downstream targets of FOXO1 are involved in palmitate-induced apoptosis in the pancreatic beta cell line MIN6.

METHODS

Chromatin immunoprecipitation (ChIP) coupled to a DNA selection and ligation technique (ChIP-DSL) was used to identify the direct targets of FOXO1. The mRNA level was examined by real-time PCR assay. The ChIP-DSL results were verified using ChIP-PCR and luciferase assay, respectively. The cell apoptosis rate was determined by TUNEL assay and by scoring cells with pycnotic nuclei.

RESULTS

We identified 189 target genes and selected 106 targets for expression analysis in MIN6 cells treated with palmitate. The results showed that six genes were significantly upregulated and four were downregulated. Binding of FOXO1 to the promoters was determined by ChIP-PCR and confirmed by luciferase assay. Among the ten up- and downregulated genes, mRNA expression of A930038C07Rik was significantly decreased and that of Ppa1 was increased in 8-week-old db/db mice. The apoptosis assay showed that overproduction of the protein 'RIKEN cDNA A930038C07' (A930038C07Rik) drastically enhanced palmitate-induced apoptosis, while pyrophosphatase (inorganic) 1 (PPA1) partially protected the cells from apoptosis. Knockdown of PPA1, moreover, significantly increased apoptosis.

CONCLUSIONS/INTERPRETATION

We identified for the first time FOXO1 targets in MIN6 cells treated with palmitate, thus revealing the important roles of A930038C07Rik and PPA1 in palmitate-induced cell apoptosis. These results shed light on the mechanisms of palmitate-induced apoptosis in pancreatic beta cells.

Overexpression of ECM1 contributes to migration and invasion in cholangiocarcinoma cell

Although the expression of extracellular matrix protein-1 (ECM1) has been documented in several tumor models, the function of ECM1 has remained unclear. In this study, expression of ECM1 was detected by real time PCR and immunohistochemistry. The role and mechanism of ECM1 overexpression in cholangiocarcinoma (CCA) cells were assessed by wound-healing, matrigel invasion assay and Western blotting. Expression of ECM1 was significantly elevated in CCA tissues than that in adjacent noncancerous, cholangitis and normal bile duct tissues. Its overexpression was associated with poor differentiation, lymph node metastasis, poor prognosis, and the level of CA199, MMP-9, estrogen receptor. Knockdown of ECM1 suppressed migration and invasion of CCA cells. Using PI3K or IKK inhibitor reduced the level of phospho-Akt or phospho-IκBα as well as ECM1. Taken together, overexpression of ECM1 may contribute to CCA initiation and progression through promoting migration and invasion of CCA cells, its overexpression was associated with Akt/NF-κB signaling axis.

Interface control of bulk ferroelectric polarization

The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.

Temperature-dependent ideal strength and stacking fault energy of fcc Ni: a first-principles study of shear deformation

Variations of energy, stress, and magnetic moment of fcc Ni as a response to shear deformation and the associated ideal shear strength (τ(IS)), intrinsic (γ(SF)) and unstable (γ(US)) stacking fault energies have been studied in terms of first-principles calculations under both the alias and affine shear regimes within the {111} slip plane along the <112> and <110> directions. It is found that (i) the intrinsic stacking fault energy γ(SF) is nearly independent of the shear deformation regimes used, albeit a slightly smaller value is predicted by pure shear (with relaxation) compared to the one from simple shear (without relaxation); (ii) the minimum ideal shear strength τ(IS) is obtained by pure alias shear of {111}<112>; and (iii) the dissociation of the 1/2[110] dislocation into two partial Shockley dislocations (1/6[211] + 1/6[121]) is observed under pure alias shear of {111}<110>. Based on the quasiharmonic approach from first-principles phonon calculations, the predicted γ(SF) has been extended to finite temperatures. In particular, using a proposed quasistatic approach on the basis of the predicted volume versus temperature relation, the temperature dependence of τ(IS) is also obtained. Both the γ(SF) and the τ(IS) of fcc Ni decrease with increasing temperature. The computed ideal shear strengths as well as the intrinsic and unstable stacking fault energies are in favorable accord with experiments and other predictions in the literature.

Electric-field control of nonvolatile magnetization in Co40Fe40B20/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O3 structure at room temperature

We report a large and nonvolatile bipolar-electric-field-controlled magnetization at room temperature in a Co(40)Fe(40)B(20)/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O(3) structure, which exhibits an electric-field-controlled looplike magnetization. Investigations on the ferroelectric domains and crystal structures with in situ electric fields reveal that the effect is related to the combined action of 109° ferroelastic domain switching and the absence of magnetocrystalline anisotropy in Co(40)Fe(40)B(20). This work provides a route to realize large and nonvolatile magnetoelectric coupling at room temperature and is significant for applications.

Microscopic origin of the giant ferroelectric polarization in tetragonal-like BiFeO(3)

We report direct experimental evidence for a room-temperature, ∼130  μC/cm(2) ferroelectric polarization from the tetragonal-like BiFeO(3) phase. The physical origin of this remarkable enhancement of ferroelectric polarization has been investigated by a combination of x-ray absorption spectroscopy, scanning transmission electron microscopy, and first principles calculations. A large strain-induced Fe-ion displacement relative to the oxygen octahedra, combined with the contribution of Bi 6s lone pair electrons, is the mechanism driving the large ferroelectric polarization in this tetragonal-like phase.

Molecular cloning, functional characterization and phylogenetic analysis of TRAIL in Japanese pufferfish Takifugu rubripes

In this study, the complementary DNA (cDNA) of Japanese pufferfish Takifugu rubripes tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) was cloned by reverse-transcription PCR. The open reading frame of the TRAIL consisted of 870 bases. The deduced amino-acid sequence of the TRAIL showed a high homology with the sequences of other teleosts. Recombinant soluble TRAIL was fused with a small ubiquitin-related modifier gene to enhance the soluble expression level in Escherichia coli BL21 (DE3). In vitro, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide (MTT) assay indicated that the purified soluble TRAIL was able to induce apoptosis of Jurkat and HeLa cells in a dose-dependent manner.

Current progress of the biological single-ion microbeam at FUDAN

A biological microbeam for precisely positioned single-ion/single cell irradiation is built in the Institute of Modern Physics in Fudan University, Shanghai, China, based on the tandem accelerator (2 × 3MV) in the laboratory. In this paper, the developing progress of the FUDAN microbeam is reported, including the newly constructed beam line, the microbeam collimator, the ion detection system, and the cell-imaging and targeting systems. Statistical models are proposed for evaluating the spatial resolution and dosage precision of the microbeam. By taking the collimated ions as a Gaussian beam, the spatial resolution can be evaluated by the full width at half maximum of the 2-D Gaussian distribution, which is determined by fitting the proportions of peripheral pits outside specific radii in the pit clusters etched on ion track detectors to a 2-D Gaussian distribution. In the preset hitting of defined ion number, by taking the real delivered number of ions as an independent identically distributed random variable (iidrv), according to the Law of Large Numbers and Central Limit Theorem, the expected value μ and standard deviation σ of the real delivered ion number in a preset N-ion hitting can be determined by approaching the normal distribution of N (μ, σ (2)/n) with the proportions of the mean counts of pits in multiple pit clusters on ion track detectors. By the values of μ, σ and additional assumptions, statistical dosage precision evaluations can be made on the preset hitting. From the linear fit curve of μ(N) and the power function fit curve of σ(N) on different preset ion numbers, characteristic factors k, b, A, p can be extracted for a precision evaluation independent of the specific preset ion number.

An integrated mathematical model of thrombin-, histamine-and VEGF-mediated signalling in endothelial permeability

BACKGROUND

Endothelial permeability is involved in injury, inflammation, diabetes and cancer. It is partly regulated by the thrombin-, histamine-, and VEGF-mediated myosin-light-chain (MLC) activation pathways. While these pathways have been investigated, questions such as temporal effects and the dynamics of multi-mediator regulation remain to be fully studied. Mathematical modeling of these pathways facilitates such studies. Based on the published ordinary differential equation models of the pathway components, we developed an integrated model of thrombin-, histamine-, and VEGF-mediated MLC activation pathways.

RESULTS

Our model was validated against experimental data for calcium release and thrombin-, histamine-, and VEGF-mediated MLC activation. The simulated effects of PAR-1, Rho GTPase, ROCK, VEGF and VEGFR2 over-expression on MLC activation, and the collective modulation by thrombin and histamine are consistent with experimental findings. Our model was used to predict enhanced MLC activation by CPI-17 over-expression and by synergistic action of thrombin and VEGF at low mediator levels. These may have impact in endothelial permeability and metastasis in cancer patients with blood coagulation.

CONCLUSION

Our model was validated against a number of experimental findings and the observed synergistic effects of low concentrations of thrombin and histamine in mediating the activation of MLC. It can be used to predict the effects of altered pathway components, collective actions of multiple mediators and the potential impact to various diseases. Similar to the published models of other pathways, our model can potentially be used to identify important disease genes through sensitivity analysis of signalling components.

Large field-induced strains in a lead-free piezoelectric material

Piezoelectric materials exhibit a mechanical response to electrical inputs, as well as an electrical response to mechanical inputs, which makes them useful in sensors and actuators. Lead-based piezoelectrics demonstrate a large mechanical response, but they also pose a health risk. The ferroelectric BiFeO(3) is an attractive alternative because it is lead-free, and because strain can stabilize BiFeO(3) phases with a structure that resembles a morphotropic phase boundary. Here we report a reversible electric-field-induced strain of over 5% in BiFeO(3) films, together with a characterization of the origins of this effect. In situ transmission electron microscopy coupled with nanoscale electrical and mechanical probing shows that large strains result from moving the boundaries between tetragonal- and rhombohedral-like phases, which changes the phase stability of the mixture. These results demonstrate the potential of BiFeO(3) as a substitute for lead-based materials in future piezoelectric applications.

Reversible electric control of exchange bias in a multiferroic field-effect device

Electric-field control of magnetization has many potential applications in magnetic memory storage, sensors and spintronics. One approach to obtain this control is through multiferroic materials. Instead of using direct coupling between ferroelectric and ferromagnetic order parameters in a single-phase multiferroic material, which only shows a weak magnetoelectric effect, a unique method using indirect coupling through an intermediate antiferromagnetic order parameter can be used. In this article, we demonstrate electrical control of exchange bias using a field-effect device employing multiferroic (ferroelectric/antiferromagnetic) BiFeO(3) as the dielectric and ferromagnetic La(0.7)Sr(0.3)MnO(3) as the conducting channel; we can reversibly switch between two distinct exchange-bias states by switching the ferroelectric polarization of BiFeO(3). This is an important step towards controlling magnetization with electric fields, which may enable a new class of electrically controllable spintronic devices and provide a new basis for producing electrically controllable spin-polarized currents.

Acute effects of sublingual buprenorphine on brain responses to heroin-related cues in early-abstinent heroin addicts: an uncontrolled trial

Replacement therapy with buprenorphine is clinically effective in reducing withdrawal and craving for heroin during detoxification but not in decreasing the probability of relapse after detoxification. This study examined the acute effects of buprenorphine on brain responses to heroin-related cues to reveal the neurobiological and therapeutic mechanisms of addiction and relapse. Fifteen heroin addicts at a very early period of abstinence, were studied in two separate periods 10-15 min apart: an early period (5-45 min) and a later period (60-105 min) after sublingual buprenorphine, roughly covering the onset and peak of buprenorphine plasma level. During both periods, fMRI scanning with heroin-related visual stimuli were performed followed by questionnaires. Under effect of buprenorphine, brain responses to heroin-related cues showed decrease in amygdala, hippocampus, ventral tegmental area (VTA) and thalamus but no changes in ventral striatum and orbital-prefrontal-parietal cortices. As an uncontrolled trial, these preliminary results suggest that buprenorphine has specific brain targets in reducing withdrawal and craving during early abstinence, and that ventral striatum and orbital-prefrontal-parietal cortices may be the key targets in developing therapy for drug addiction and relapse.

Interface ferromagnetism and orbital reconstruction in BiFeO3-La(0.7)Sr(0.3)MnO3 heterostructures

We report the formation of a novel ferromagnetic state in the antiferromagnet BiFeO3 at the interface with ferromagnet La(0.7)Sr(0.3)MnO3. Using x-ray magnetic circular dichroism at Mn and Fe L(2,3) edges, we discovered that the development of this ferromagnetic spin structure is strongly associated with the onset of a significant exchange bias. Our results demonstrate that the magnetic state is directly related to an electronic orbital reconstruction at the interface, which is supported by the linearly polarized x-ray absorption measurement at the oxygen K edge.

Neural correlates of the orthographic neighborhood size effect in Chinese

Word recognition research with alphabetical scripts has revealed a facilitatory neighborhood size effect, whereby naming of words with more orthographic neighbors is faster than that of words with fewer neighbors. Preliminary behavioral evidence in Chinese revealed both facilitatory and inhibitory neighborhood size effects, depending on whether there are higher-frequency neighbors (HFNs) than the target. This functional magnetic resonance imaging study examined the neural substrates of the neighborhood size effect with silent naming. Neighborhood size and the HFN factor were factorially manipulated. Behavioral results replicated previous findings showing that larger neighborhood size facilitated naming in the absence of HFNs, but inhibited naming in their presence. Imaging results identified greater activation in the left middle frontal gyrus for small than larger neighborhood size, and bilateral inferior frontal activations for the with-HFN condition as compared with the without-HFN condition. Critically, there was an interaction in the right middle occipital gyrus showing greater activation for large than for small neighborhood size in the absence of HFNs but no neighborhood size effect in their presence. The results support a proposal that, in addition to a facilitatory contribution from orthographic activation of neighborhoods, naming is also affected by whether there are higher-frequency neighbors, particularly in scripts with deep orthography, where orthographically similar words can be pronounced very differently.