Elastic trapping of dislocation loops in cascades in ion-irradiated tungsten foils

Using in situ transmission electron microscopy (TEM), we have observed nanometre scale dislocation loops formed when an ultra-high-purity tungsten foil is irradiated with a very low fluence of self-ions. Analysis of the TEM images has revealed the largest loops to be predominantly of prismatic 1/2〈111〉 type and of vacancy character. The formation of such dislocation loops is surprising since isolated loops are expected to be highly mobile, and should escape from the foil. In this work we show that the observed size and number density of loops can be explained by the fact that the loops are not isolated-the loops formed in close proximity in the cascades interact with each other and with vacancy clusters, also formed in cascades, through long-range elastic fields, which prevent the escape of loops from the foil. We find that experimental observations are well reproduced by object Kinetic Monte Carlo simulations of evolution of cascades only if elastic interaction between the loops is taken into account. Our analysis highlights the profound effect of elastic interaction between defects on the microstructural evolution of irradiated materials.

Risk factors of venous thrombosis in patients with ankle fractures

AIM

Deep vein thrombosis (DVT) is a major complication that can occur after injuries. our aim was to explore the incidence and risk factors of venous thromboembolism in patients with ankle fractures.

METHODS

Consecutive patients with an isolated fracture of the ankle presenting at our centre between Sept 2004 and May 2012 were studied. They were investigated for venous thrombosis by Doppler sonography (DUS) before surgery. Univariate and multivariate logistic regressions analyses were performed to identify the incidence and risk factors for venous thromboembolism.

RESULTS

A total of 2347 patients were studied in the research. Of these, only 119 patients suffered from DVT. The multivariable analyses showed that diabetes, less activity and the time from injury were the key risk factors for thrombosis.

CONCLUSION

In patients with ankle fracture, the risk of thrombosis was low and it may not need warrant routine thromboprophylaxis. However, most cases had no significant symptoms, is necessary to grasp the indications for high risk patients to reduce the incidence rate of venous thrombosis.

Matrine-induced apoptosis of human nasopharyngeal carcinoma cells via in vitro vascular endothelial growth factor-A/extracellular signal-regulated kinase1/2 pathway inactivation

Matrine, a main active extract from Sophora flavescens Ait, has been demonstrated to exert anticancer effects on various cancer cell lines, such as malignant melanoma, breast cancer, and lung cancer. However, it is currently unclear whether matrine could also elicit an inhibitory effect on growth of nasopharyngeal carcinoma (NPC), let alone the possible molecular mechanisms. Therefore, in a previous study, we investigated matrine-induced proliferation inhibition and apoptosis in NPC cells. It was shown that proliferation of human NPC cells (CNE1 and CNE2) was significantly diminished by matrine in a dose- and time-dependent manner, and apoptosis was induced in both 2 NPC cells, particularly in CNE2 cells. Moreover, the increased apoptosis rate in matrine-treated CNE2 cells confirmed the proapoptotic activity of matrine. We further found that matrine treatment dose- and time-dependently reduced the levels of vascular endothelial growth factor-A (VEGF-A), and inactivated extracellular signal-regulated kinase1/2 (ERK1/2), followed by increased expression of downstream target caspase-3. Overall, we conclude that matrine could induce apoptosis of human NPC cells via VEGF-A/ERK1/2 pathway, which supports the potential use of matrine in clinically treating NPC.

Multiple amino acid mutations in viral RNA polymerase may synergistically enhance the transmissibility and/or virulence of the 2009 pandemic influenza (H1N1) virus

Influenza viruses may change their transmissibility and virulence via single or multiple point mutations in the functional regions of their structural proteins. In this study, we compared sequences of all three subunits of viral RNA polymerase, i.e. PA, PB1 and PB2, of the 2009 pandemic influenza A (H1N1) virus isolates from different stages of the pandemic and found that the frequencies of three mutations, including V14I and K716Q in PA and K736G in PB1, showed a similar trend. Interestingly, the death rate of infected patients during the pandemic matched the frequency of the three mutations with a 2-months delay. These findings suggest that the combined mutations may have acted synergistically in enhancing the transmissibility and/or virulence of the 2009 pandemic virus. If definitely proved, this hypothesis could guide the rational design of antiviral therapeutics targeting the RNA polymerase of influenza viruses.

Scatter hoarding and hippocampal cell proliferation in Siberian chipmunks

Food hoarding, especially scatter hoarding and retrieving food caches, requires spatial learning and memory and is an adaptive behavior important for an animal's survival and reproductive success. In the present study, we examined the effects of hoarding behavior on cell proliferation and survival in the hippocampus of male and female Siberian chipmunks (Tamias sibiricus). We found that chipmunks in a semi-natural enclosure displayed hoarding behavior with large individual variations. Males ate more scatter-hoarded seeds than females. In addition, the display of hoarding behavior was associated with increased cell proliferation in the hippocampus and this increase occurred in a brain region-specific manner. These data provide further evidence to support the notion that new cells in the adult hippocampus are affected by learning and memory tasks and may play an important role in adaptive behavior.

The prevalence of isolated calf deep vein thrombosis in patients with pulmonary embolism

AIM

Due to discordant results, the risk of isolated calf deep vein thrombosis (DVT) -associated pulmonary embolism (PE) is not well established. This study aimed to detect the prevalence of isolated calf DVT in patients with PE, discussing the importance of isolated calf DVT.

METHODS

We retrospectively reviewed all the inpatients that were both diagnosed PE and DVT between November 2002 and February 2010 in our hospital, analyzed the prevalence of isolated calf DVT and the relevance details.

RESULTS

Among all the 63 patients who were diagnosed both PE and DVT, isolated calf DVT was detected in 23 limbs in 16 patients (16/63=25.4%). Soleal vein was the most frequently involved, with 14 limbs. Ten of the patients had low risk PE, 3 had submassive PE and 3 had massive PE. In the 6 patient who had submassive and massive PE, 4 had bilateral leg calf DVT and all 6 were multiple calf vein involvement.

CONCLUSION

Our results reflected the prevalence of PE at presentation, which was high and included severe cases. Though, as reported, PE during surveillance was the most precisely way to reflect PE in isolated calf DVT, but such a risk of PE at presentation should not just be ignored and its importance still needs to be discussed. Well-designed and adequately powered studies are needed to give strong evidence to recognize the real risk of isolated calf DVT, either at presentation or at surveillance, to distinguish the one with high risk and determine appropriate way to treat it.

Microwave photonic signal processing

Photonic signal processing offers the advantages of large time-bandwidth capabilities to overcome inherent electronic limitations. In-fibre signal processors are inherently compatible with fibre optic microwave systems that can integrate with wireless antennas, and can provide connectivity with in-built signal conditioning and electromagnetic interference immunity. Recent methods in wideband and adaptive signal processing, which address the challenge of realising programmable microwave photonic phase shifters and true-time delay elements for phased array beamforming; ultra-wideband Hilbert transformers; single passband, widely tunable, and switchable microwave photonic filters; and ultra-wideband microwave photonic mixers, are described. In addition, a new microwave photonic mixer structure is presented, which is based on using the inherent frequency selectivity of the stimulated Brillouin scattering loss spectrum to suppress the carrier of a dual-phase modulated optical signal. Results for the new microwave photonic mixer demonstrate an extremely wide bandwidth operation of 0.2 to 20 GHz and a large conversion efficiency improvement compared to the conventional microwave photonic mixer.

Terbinafine inhibits KSR1 and suppresses Raf-MEK-ERK signaling in oral squamous cell carcinoma cells

Terbinafine inhibits the proliferation of many types of cancer cells, but the underlying mechanism remains to be determined. By computer simulation, we found that kinase suppressor of Ras 1 (KSR1) is a possible target of terbinafine. Treatment of human oral squamous cell carcinoma (OSCC) KB cells with either terbinafine or siRNA to knockdown KSR1 reduced proliferation and induced apoptosis, which was accompanied by suppression of the Raf-MEK-ERK pathway. In vivo, KSR1 expression was significantly associated with the clinical staging of OSCC and the smoking habit of patients. Kaplan Meyer survival analysis demonstrated that the cumulative survival time of patients without KSR1 expression was significantly longer than those with KSR1 overexpression. Our data provide the basis for developing terbinafine to treat OSCC.

[Determination of commonly abused dyes in food by liquid chromatography-tandem mass spectrometry]

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of commonly abused dyes in candy, sirup, liquid milk and fruit juice. The test sample was dissolved and diluted with water, then cleaned up by polyamide solid phase extraction. The LC separation was performed on an Agilent XDB-C18 column with 20 mmol/L ammonium acetate solution and acetonitrile as the mobile phase in a gradient elution mode. The dyes were determined by MS/MS in negative electrospray ionization mode, and quantified by matrix-matched external standard method. The calibration curves showed good linearity in the range of 0.5 - 50 mg/L with the correlation coefficients (r) greater than 0.99. The limits of quantitation (S/N > 10) were 0.5 mg/kg, and the limits of detection (S/N > 3) were 0.1 mg/kg. The recoveries of dyes in food samples at the three spiked levels of 0.5, 5 and 50 mg/kg were in the range of 62.6% - 115.3% with the relative standard deviations (RSDs) of 2.6% - 26.3%. The method can meet the requirements for the determination of the dyes in food samples for import and export inspection.

Novel surface display system for heterogonous proteins on Lactobacillus plantarum

AIMS

To establish a novel cell surface display system that would enable the display of target proteins on Lactobacillus plantarum.

METHODS AND RESULTS

BlastP analysis of the amino acids sequence data revealed that the N-terminus of the putative muropeptidase MurO from L. plantarum contained two putative lysin motif (LysM) repeat regions, implying that the MurO was involved in bacterial cell wall binding. To investigate the potential of MurO for surface display, green fluorescent protein (GFP) was fused to MurO at its C-terminus and the resulting fusion protein was expressed in Escherichia coli. After being mixed with L. plantarum cells in vitro, GFP was successfully displayed on the surfaces of L. plantarum cells. Increases in the fluorescence intensities of chemically pretreated L. plantarum cells compared to those of nonpretreated cells suggested that the peptidoglycan was the binding ligand for MurO. SDS sensitivity assay showed that the GFP fluorescence intensity was reduced after being treated with SDS. To demonstrate the applicability of the MurO-mediated surface display system, β-galactosidase from Bifidobacterium bifidium, in place of GFP, was functionally displayed on the surface of L. plantarum cells via MurO.

CONCLUSIONS

The MurO was a novel anchor protein for constructing a surface display system for L. plantarum.

SIGNIFICANCE AND IMPACT OF STUDY

The success in surface display of GFP and β-galactosidase opened up the feasibility of employing the cell wall anchor of MurO for surface display in L. plantarum.

[Determination of linuron and its metabolite 3,4-dichloroaniline residues in meat and meat products using liquid chromatography-tandem mass spectrometry]

A method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of linuron and its metabolite 3, 4-dichloroaniline residues in pork, liver, kidney, casings, canned steam pork and sausage. The sample was extracted with a mixture of acetone-acetonitrile (5: 95, v/v). Most of the lipids in the extract were eliminated by freezing-lipid filtration. After Florisil solid phase extraction cleanup, the linuron and its metabolite residues were determined by LC-MS/MS, and quantified by internal standard meth-od. In the range of 1 - 500 microg/L, both linuron and 3,4-dichloroaniline showed good linearity with the correlation coefficients (r) more than 0. 998. The limit of quantification (S/N > 10) was 10 microg/kg, and the limit of detection (S/N > 3) was 5 microg/kg for each analyte. The recoveries of linuron and 3,4-dichloroaniline in meat and meat products at three spiked levels were in the ranges of 88.3% - 101.2% and 91.6% - 101. 6%, and the relative standard deviations were in the ranges of 4. 8% - 13. 7% and 4. 7% - 11. 8%, respectively. The results demonstrated that the proposed method can meet the requirements for the determination of linuron and 3,4-dichloroaniline in meat and meat products.

Characterization of 236 novel alleles at the HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci from China Marrow Donor Program

Two hundred and thirty-six novel human leukocyte antigen (HLA) alleles are described from volunteer donors of the China Marrow Donor Program: 71 HLA-A alleles, 79 HLA-B alleles, 43 HLA-C, 16 HLA-DRB1 alleles, 26 HLA-DQB1 and 1 HLA-DPB1. Two hundred and thirteen (90.3%) of the 236 novel alleles are single nucleotide substitution variants when compared with their most homologous allele. Seventy-eight of these single nucleotide variants are silent substitutions. The remaining novel alleles differ from their most similar allele by two to four nucleotide substitutions. Some of the novel alleles encode amino acid changes at positions not previously reported to be polymorphic, such as codons 57, 62, 67, 41 and 52 in HLA-A alleles; codons 133, 156, 201 and 215 in HLA-B alleles; codons 74, 208 and 225 in HLA-C; codons 25, 32 and 72 in HLA-DRB1; codons 20, 39 and 77 in HLA-DQB1.

Principles of strategic drug delivery to the brain (SDDB): development of anorectic and orexigenic analogs of leptin

The blood-brain barrier (BBB) presents a tremendous challenge for the delivery of drugs to the central nervous system (CNS). This includes drugs that target brain receptors for the treatment of obesity and anorexia. Strategic drug delivery to brain (SDDB) is an approach that considers in depth the relations among the BBB, the candidate therapeutic, the CNS target, and the disease state to be treated. Here, we illustrate principles of SDDB with two different approaches to developing drugs based on leptin. In normal body weight humans and in non-obese rodents, leptin is readily transported across the BBB and into the CNS where it inhibits feeding and enhances thermogenesis. However, in obesity, the transport of leptin across the BBB is impaired, resulting in a resistance to leptin. As a result, it is difficult to treat obesity with leptin or its analogs that depend on the leptin transporter for access to the CNS. To treat obesity, we developed a leptin agonist modified by the addition of pluronic block copolymers (P85-leptin). P85-leptin retains biological activity and is capable of crossing the BBB by a mechanism that is not dependent on the leptin transporter. As such, P85-leptin is able to cross the BBB of obese mice at a rate similar to that of native leptin in lean mice. To treat anorexia, we developed a leptin antagonist modified by pegylation (PEG-MLA) that acts primarily by blocking the BBB transporter for endogenous, circulating leptin. This prevents blood-borne, endogenous leptin from entering the CNS, essentially mimicking the leptin resistance seen in obesity, and resulting in a significant increase in adiposity. These examples illustrate two strategies in which an understanding of the interactions among the BBB, CNS targets, and candidate therapeutics under physiologic and diseased conditions can be used to develop drugs effective for the treatment of brain disease.

Determination of methanol in cosmetics by headspace and multidimensional gas chromatography with mass spectrometric detection

A novel, reliable, and robust analytical method using headspace and multidimensional GC coupled to MS was successfully developed for determining the methanol content in cosmetics. The methanol was quantitatively analyzed and confirmed by heart-cutting multidimensional GC and mass selective detection in full scan mode. The average recovery was 99.8% with an RSD of 4.3%; the LOQ was 5 mg/kg. The proposed method showed good accuracy and precision while minimizing erroneous results due to false positives compared with conventional single-column GC analysis.

Determination of Methanol in Cosmetics by Headspace and Multidimensional Gas Chromatography with Mass Spectrometric Detection

A novel, reliable, and robust analytical method using headspace and multidimensional GC coupled to MS was successfully developed for determining the methanol content in cosmetics. The methanol was quantitatively analyzed and confirmed by heart-cutting multidimensional GC and mass selective detection in full scan mode. The average recovery was 99.8 with an RSD of 4.3; the LOQ was 5 mg/kg. The proposed method showed good accuracy and precision while minimizing erroneous results due to false positives compared with conventional single-column GC analysis.

Regulation of non-AU-rich element containing c-fms proto-oncogene expression by HuR in breast cancer

The role of RNA-binding proteins in cancer biology is recognized increasingly. The nucleocytoplasmic shuttling and AU-rich RNA-binding protein HuR stabilizes several cancer-related target mRNAs. The proto-oncogene c-fms, whose 3'untranslated region (3'UTR) is not AU-rich, is associated with poor prognosis in breast cancer. Using a large breast-cancer tissue array (N=670), we found nuclear HuR expression to be associated with nodal metastasis and independently with poor survival (P=0.03, RR 1.45), as well as to be co-expressed with c-fms in the breast tumors (P=0.0007). We described c-fms mRNA as a direct target of HuR in vivo, and that HuR bound specifically to a 69-nt region containing 'CUU' motifs in 3'UTR c-fms RNA. Overexpressing or silencing HuR significantly up- or down-regulated c-fms RNA expression, respectively. We also found that known glucocorticoid stimulation of c-fms RNA and protein is largely dependent on the presence of HuR. HuR, by binding to the 69-nt wild type, but not mutant, c-fms sequence can regulate reporter gene expression post-transcriptionally. We are the first to describe that HuR can regulate gene expression by binding non-AU-rich sequences in 3'UTR c-fms RNA. Collectively, our findings suggest that HuR plays a supportive role for c-fms in breast cancer progression by binding a 69-nt element in its 3'UTR, thus regulating its expression.