Multi-Level Thresholding Image Segmentation Based on Improved Slime Mould Algorithm and Symmetric Cross-Entropy.

Multi-level thresholding image segmentation divides an image into multiple regions of interest and is a key step in image processing and image analysis. Aiming toward the problems of the low segmentation accuracy and slow convergence speed of traditional multi-level threshold image segmentation methods, in this paper, we present multi-level thresholding image segmentation based on an improved slime mould algorithm (ISMA) and symmetric cross-entropy for global optimization and image segmentation tasks. First, elite opposition-based learning (EOBL) was used to improve the quality and diversity of the initial population and accelerate the convergence speed. The adaptive probability threshold was used to adjust the selection probability of the slime mould to enhance the ability of the algorithm to jump out of the local optimum. The historical leader strategy, which selects the optimal historical information as the leader for the position update, was found to improve the convergence accuracy. Subsequently, 14 benchmark functions were used to evaluate the performance of ISMA, comparing it with other well-known algorithms in terms of the optimization accuracy, convergence speed, and significant differences. Subsequently, we tested the segmentation quality of the method proposed in this paper on eight grayscale images and compared it with other image segmentation criteria and well-known algorithms. The experimental metrics include the average fitness (mean), standard deviation (std), peak signal to noise ratio (PSNR), structure similarity index (SSIM), and feature similarity index (FSIM), which we utilized to evaluate the quality of the segmentation. The experimental results demonstrated that the improved slime mould algorithm is superior to the other compared algorithms, and multi-level thresholding image segmentation based on the improved slime mould algorithm and symmetric cross-entropy can be effectively applied to the task of multi-level threshold image segmentation.

Active metasurface in the near-infrared region by gating ultrathin TiN films.

Ultrathin titanium nitride (TiN) films have become a novel material flatform for constructing active metasurfaces in the near-infrared region. In this Letter, we numerically achieved the dual functions of switchable linear dichroism (LD) and tunable perfect absorption in a G-shape gold resonators/TiN film hybrid metasurface by gating ultrathin TiN films. As the carrier density of TiN decreases, the modulation depth for LD strength is about 70% at 1211 nm. Meanwhile, the response wavelength of perfect absorption (∼1) shifts to the blue by around 130 nm with a change of carrier density of 12%. Our proposed active metasurface with the capability of strength-switchable LD and wavelength-tunable perfect absorption has considerable potential in dynamic electro-optic modulation and flat photonic devices with reconfigurable functionalities.

Ultrafast and surfactant-free synthesis of Sub-3 nm nanoalloys by shear-assisted liquid-metal reduction.

The uniform and surfactant-free synthesis of ultrafine alloy nanoparticles (NPs) still remains an ongoing challenge. Here, we developed a general route for synthesizing sub-3 nm nanoalloys on a carbon support via a shear-assisted liquid-metal reduction (SA-LMR) strategy. The utilization of shearing treatment resulted in the rapid release of electrons from the liquid sodium-potassium (NaK) alloy, which enabled the ultrafast reduction of precursor metal ions to metallic nanoalloys at room temperature. As a model system, Pt-Cu NPs with uniform distribution were synthesized and characterized by spectroscopic and microscopic techniques. The size, composition and structure of the Pt-Cu NPs could be tuned by controlling the volume of liquid NaK alloy and the reaction time. To prove the universality and utility of our method, the binary Pt-M (Fe, Co, Ni, and Cu) and ternary Pt-Cu-Fe nanoalloys deposited on a carbon support were prepared as hydrogen evolution reaction (HER) catalysts. This facile, rapid and universal synthesis technique has the potential to be employed in the large-scale production of nanomaterials and suggests a new direction for nanoalloys.

Characterization of HIV-1 genotype specific antigens for the detection of recent and long-term HIV-1 infection in China.

To characterize HIV-1 gp41 as an antigen for developing HIV-1 incidence assay and to investigate the impact of HIV-1 genetic diversity on the assay performance, a number of truncated peptides were synthesized to identify the immunodominant epitopes (IDEs) of HIV-1 gp41 protein. Subsequently, the mixed peptides (MP3) or the recombinant protein (MP4) containing HIV-1 gp41 IDEs of the major HIV-1 genotype CRF01_AE, CRF07_BC/ CRF08_BC and subtype B in China were used to verify the sensitivity and specificity of HIV-1 recency testing. We identified the QKFLG and GKIIC motifs located in the loop region of HIV-1 gp41 as the two major IDEs. The surrounding amino acids EAQQHLLQLT and WNSSWSN could block the binding of gp41 peptide and anti-HIV antibody with low avidity, making the gp41 peptide p57 suitable for distinguishing recent and long-term HIV-1 infections. Furthermore, MP3 or MP4-based immunoassay could significantly improve the assay sensitivity and showed 93.33% (140/150) vs. 94.59% (35/37) and 94.08% (143/152) vs. 94.59% (35/37) concordance with commercially available LAg-Avidity EIA test among the cross-sectional and longitudinal samples, respectively. The estimated mean duration of recent infection (MDRI) was 130 days (95% CI: 83-167) and 166 days (95% CI: 123-202) for MP3 and MP4 assays, respectively. Our preliminary results indicate that the HIV-1 gp41 peptide-based immunoassay specifically targeting the major HIV-1 genotype CRF01_AE, CRF07_BC/CRF08_BC and subtype B could serve as a simple incidence assay for differentiating recent and long-term HIV-1 infections in China.

Free-Standing SnO2@rGO Anode via the Anti-solvent-assisted Precipitation for Superior Lithium Storage Performance.

Metal oxides have been attractive as high-capacity anode materials for lithium-ion batteries. However, oxide anodes encounter drastic volumetric changes during lithium ion storage through the conversion reaction and alloying/dealloying processes, leading to rapid capacity decay and poor cycling stability. Here, we report a free-standing SnO2@reduced graphene oxide (SnO2@rGO) composite anode, in which SnO2 nanoparticles are tightly wrapped within wrinkled rGO sheets. The SnO2@rGO sheet is assembled in high porosity via an anti-solvent-assisted precipitation of dispersed SnO2 nanoparticles and graphene oxide sheets in the distilled water, followed by the filtration and post-annealing processes. Significantly enhanced lithium storage performance has been obtained of the SnO2@rGO anode compared with the bare SnO2 anode material. A high charge capacity above 700 mAh g-1 can be achieved with a satisfying 95.6% retention after 50 cycles at a current density of 500 mA g-1, superior to reserved 126 mAh g-1 and a much lower 16.8% retention of the bare SnO2 anode. XRD pattern and HRTEM images of the cycled SnO2@rGO anode material verify the expected oxidation of Sn to SnO2 at the fully-charged state in the 50th cycle. In addition, FESEM and TEM images reveal the well-preserved free-standing structure after cycling, which accounts for high reversible capacity and excellent cycling stability of such a SnO2@rGO anode. This work provides a promising SnO2-based anode for high-capacity lithium-ion batteries, together with an effective fabrication adoptable to prepare different free-standing composite materials for device applications.

Genetic characterization of a novel HIV-1 CRF01_AE/CRF07_BC recombinant form among men who have sex with men in Guangdong, China.

Genome recombination is a major strategy employed by HIV to generate new variants for the benefit of escaping immune surveillance. Near full-length genome phylogenic analysis was utilized to characterize HIV diversity in a male patient in Guangdong, China. The result showed a unique recombinant form (URF) composed of two circulating recombinant forms, CRF01_AE (92%) and CRF07_BC (8%), using six recombinant breakpoints, nt 2794, 3092, 4482, 5988, 7021, and 7722. The emergence of this URF indicates that HIV-1 co-infection or super-infections are common. The increasing genetic complexity of the HIV-1 epidemic in China warrants continued investigation.

Metabolic syndrome is associated with increased risk of Barrett esophagus: A meta-analysis.

BACKGROUND: Barrett esophagus (BE) is considered precursor condition of esophageal adenocarcinoma. Its incidence and prevalence are increasing in general population. Studies reported that metabolic syndrome (MS) or diabetes mellitus (DM) is related to increased risk of BE. Current study was to assess and better understand the relationship between MS /DM and BE. METHODS: Electronic search was conducted in the database Pubmed/Medline (-December, 2015), Embase (-December, 2015), Cochrane Library (-December, 2015), and Web of Knowledge (-December, 2015). Studies included were assessed with summary odds ratios (ORs) with 95% confidence intervals (CIs) and compared exposure group with control group. The heterogeneity was examined by the funnel plot and the Egger's test. Subgroup analyses and sensitive analyses were performed for the detection of possible heterogeneity and impact on stability of analysis results. RESULTS: Twelve publications met the criteria and included 355,311 subjects were analyzed. The pooled results showed MS was closely associated with increased risk of BE (OR = 1.23; 95%CI 1.03-1.47; P = 0.024), and yet DM did not significantly increase the risk of BE (OR = 1.07; 95%CI 0.82-1.38; P = 0.627). Substantial heterogeneities were detected. No significant publication bias was detected by Egger's test (P = 0.23). CONCLUSIONS: Based on the results of current meta-analysis, MS is associated with increased risk of BE. Further long-term follow-up prospective study needs to verify the current results, and definite pathophysiological mechanism needs to be further investigated and clearly elucidated.

[Association of CCR5, CCR2 and SDF1 gene polymorphisms with HIV-1 infection in Chinese population: a meta-analysis].

OBJECTIVE: To explore the association of CCR5δ32, CCR2-64I and SDFl-3 A gene polymorphisms with HIV-1-infection in Chinese population. METHODS: A meta-analysis was performed to identify case-control studies of CCR5δ32, CCR2-64I and SDFl-3 A polymorphisms from the literatures. RESULTS: Fourteen studies of CCR5δ32 were found, involving a total of 1607 cases and 1632 controls. Compared with the wild-type homozygote wt/wt, the pooled odds ratios (95%CI) of wt/mt, mt/mt, and wt/mt+mt/mt genotypes of CCR5δ32 gene polymorphisms were 1.156 (0.808, 1.654), 0.997 (0.198, 5.022), and 1.149 (0.808, 1.634), respectively. Twelve studies of CCR2-64I were identified, including 1415 cases and 1239 controls. Compared with the wild-type homozygote wt/wt, the pooled odds ratios (95%CI) of wt/mt, mt/mt, and wt/mt+mt/mt genotypes of CCR2-64I gene polymorphisms were 1.005 (0.844, 1.197), 1.191 (0.808, 1.754), and 1.028 (0.870, 1.214), respectively. Ten studies of SDFl-3 A were found, involving 1179 cases and 1003 controls. Compared with the wild-type homozygote wt/wt, the pooled odds ratios (95%CI) of wt/mt, mt/mt, and wt/mt + mt/mt genotypes of SDF1-3 A gene polymorphisms were 1.010 (0.830, 1.228), 1.188 (0.860, 1.643), and 1.038 (0.861, 1.250). CONCLUSION: CCR5δ32, CCR2-64I and SDFl-3 A gene polymorphisms do not show strong correlations to HIV-1-infection in Chinese population. These 3 genes may not have protective effect against HIV-1 infection in Chinese population, suggesting the susceptibility of Chinese population to the infection.

[Inhibitory effect of resveratrol against enterovirus type 71 in vitro].

OBJECTIVE: To observe the inhibitory effect of resveratrol against the cytopathogenicity of enterovirus type 71. METHODS: The cytotoxicity of resveratrol on Vero cells was detected using cell counting kit-8 (CCK-8). The antiviral activity of resveratrol in different stages of infection, with ribavirin as the control, was evaluated by determining the virus inhibition rate, medium effective concentration (IC(50)), and selection index (SI). RESULTS: Resveratrol was nonpoisonous to Vero cells with an median toxic concentration (TC50) of 307.6 mmol/L. Resveratrol produced an obvious inhibitory effect against enterovirus type 71 only before the cell infection by the virus (IC(50)=20.2 mmol/L , SI=15.2), and once the cells were infected, resveratrol no longer had such antiviral effect. CONCLUSIONS: Resveratrol may offer some protection against enterovirus type 71 in vitro.

A randomized controlled trial of low-dose recombinant human interferons alpha-2b nasal spray to prevent acute viral respiratory infections in military recruits.

The military population has a high disease burden of acute viral respiratory infections in China. To assess the efficacy and safety of a low-dose recombinant human interferon alpha-2b (rIFNalpha-2b) nasal spray in preventing acute viral respiratory infections in military population, we performed this randomized controlled trial. The results showed that application of the rIFNalpha-2b nasal spray had the benefits in prevention of infections caused by influenza A virus, influenza B virus parainfluenza viruses 1-3 and adenovirus species B. However, no benefit was seen in preventing respiratory syncytial virus. No severe adverse events were reported. Therefore, the rIFNalpha-2b nasal spray was effective and well tolerated for preventing common viral respiratory infections in the military recruits.

[Study on serum p53 protein in cops in Guangzhou city].

OBJECTIVE: Serum p53 protein overexpression was detected in population exposed to traffic exhaust gas to study the relation between traffic exhaust gas and the increased risk in p53 gene mutation. METHODS: Serum p53 protein expression was measured by enzyme-linked immunosorbent assay. Relationship between different types of job and serum p53 protein overexpression were studied by pearson Chi-square tests. RESULTS: Results on serum p53 protein overexpression on jobs outside of office (5.74%) were not significantly higher than jobs inside the office. However, it suggested that traffic police men (12.12%) working outside of office, with whose length of service longer than 30 years had a significant overexpression of serum p53 protein than the others (5.36%) whose length of service was less than 30 years (P < 0.05, OR = 2.43, 95% CI: 1.11 - 5.33). Overexpression rate of p53 protein appeared to be 6.89% in the group whose average weekly exposure hours were more than 40 hours, which was significant higher than the group whose exposed hours were less than 40 hours (P < 0.05, OR = 1.71, 95% CI: 1.03 - 2.81). CONCLUSION: The result suggested that traffic exhaust gas was likely to cause mutation of p53 gene and increasing the incidence of lung cancer.

[Psychological health status of students taking part in medical support for military training on the sea].

OBJECTIVE: To investigate the adaptability and psychological health status of the students from the military medical universities enrolled in the medical support service for military training on the sea, so as to provide more pertinent and specific psychological advice for students in military medical universities. METHODS: The psychological health status of 139 students were assessed by issuing a self-rating symptom scale (SCL-90) before the training and later before the maneuvers commenced, respectively. RESULTS: Except for obsessive-compulsive and interpersonal sensitivity factors, significant increases were recorded in the scores for other factors immediately before the maneuvers as compared with those recorded before the training (P<0.01, P<0.05). The positive symptom rates of various factors measured before the maneuvers were also higher. CONCLUSIONS: It is the essential task for daily psychological health education to help the students foster psychological self-regulation ability and cope with stresses to strengthen their psychological well-being. Building self-confidence, improving the adaptability and conquering fears should be the primary concern of the psychological advisors before military actions.