138 research outputs found

    USE OF CROSS-POL MULTI-TEMPORAL SAR DATA FOR IMAGE SEGMENTATION

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    The contribution to the image segmentation of multi-temporal SAR data acquired with VV - VH polarization is analyzed. The backscattering intensity, the short time interferometric coherence and the decorrelation time of scatterers have been used to separate different ground backscattering behavior both in VV and VH polarization. Then, these six parameters have been projected into a domain with reduced dimensionality by means of a Covariance Matrix Analysis. The resulting covariance values show that the main contribution to the image segmentation from the VH polarization comes when the short time interferometric coherence is different from that of the VV polarization. Preliminary results are presented on an agricultural area. Moreover, the VV-VH complex coherence has been exploited to identify urban areas and permanent scatterers. It has been verified that the coherence phase in urban environments can be only 0 or pi accordingly to the theory of dihedral and trihedral backscattering

    Promoting influenza prevention for elderly people in Hong Kong using health action process approach: Study protocol

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    Background: People 65 years or older are at greater risk of serious complications from the seasonal influenza compared with young. To promote elderly people's behavioral compliance toward influenza prevention, the aim of the current project is to develop, implement, and evaluate a theory-based low-administration-cost intervention building on a leading psychological theory, the Health Action Process Approach (HAPA). Methods: The target group is Hong Kong Chinese elderly people aged 65 or older who rarely or never adopt any preventive actions. This project will be conducted in three phases over 24 months. In phase 1, intervention program will be developed building on the HAPA theoretical framework which comprises both the initiation and maintenance of influenza prevention behaviors. In phase 2, intervention will be implemented and evaluated using a randomized controlled trial, including: (a) behavior initiation only, (b) behavior initiation + behavior maintenance, and (c) control group. Both the initiation and maintenance components will comprise weekly-delivered telephone-based individual intervention sessions in 3 months. In phase 3, outcome evaluation of behavioral and psychological variables and process evaluation will be conducted. The effectiveness of the intervention will be analyzed using a series of linear mixed models on each behavioral and psychological outcome variable. Structural equation modelling will be used to test the hypothesized theoretical sequence in the HAPA model. Discussion: The proposed project is expected to design theory-based intervention materials to promote the influenza prevention behaviors in Hong Kong elderly people and provide information on its effectiveness and the potential changing mechanism of behavior initiation and maintenance. Trial registration: This randomized controlled trial was funded by the Health and Medical Research Fund (HMRF), Food and Health Bureau of the Government of the Hong Kong Special Administrative Region (Ref: 16151222) and was registered on 13/10/2017 at CCRB Clinical Trials Registry of the Chinese University of Hong Kong, a Partner Registry of a WHO Primary Registry (Ref: CUHK-CCRB00567)

    The central region of the msp gene of Treponema denticola has sequence heterogeneity among clinical samples, obtained from patients with periodontitis

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    <p>Abstract</p> <p>Background</p> <p><it>Treponema denticola </it>is an oral spirochete involved in the pathogenesis and progression of periodontal disease. Of its virulence factors, the major surface protein (MSP) plays a role in the interaction between the treponeme and host. To understand the possible evolution of this protein, we analyzed the sequence of the <it>msp </it>gene in 17 <it>T. denticola </it>positive clinical samples.</p> <p>Methods</p> <p>Nucleotide and amino acid sequence of MSP have been determined by PCR amplification and sequencing in seventeen <it>T. denticola </it>clinical specimens to evaluate the genetic variability and the philogenetic relationship of the <it>T. denticola msp </it>gene among the different amplified sequence of positive samples. In silico antigenic analysis was performed on each MSP sequences to determined possible antigenic variation.</p> <p>Results</p> <p>The <it>msp </it>sequences showed two highly conserved 5' and 3' ends and a central region that varies substantially. Phylogenetic analysis categorized the 17 specimens into 2 principal groups, suggesting a low rate of evolutionary variability and an elevated degree of conservation of <it>msp </it>in clinically derived genetic material. Analysis of the predicted antigenic variability between isolates, demonstrated that the major differences lay between amino acids 200 and 300.</p> <p>Conclusion</p> <p>These findings showed for the first time, the nucleotide and amino acids variation of the <it>msp </it>gene in infecting <it>T. denticola</it>, <it>in vivo</it>. This data suggested that the antigenic variability found in to the MSP molecule, may be an important factor involved in immune evasion by <it>T. denticola</it>.</p

    Prognostic significance of osteopontin expression in early-stage non-small-cell lung cancer

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    Osteopontin (OPN) is a multifunctional protein, which has recently been shown to be linked to tumorigenesis, progression and metastasis in different malignancies. Since non-small-cell lung cancer (NSCLC)'s prognosis remains bad, with few predictors of outcome, the purpose of this study was to evaluate if OPN might be involved in NSCLC's biology and therefore represent a prognostic marker and a target for new therapeutic trials. Immunohistochemistry was used to detect OPN expression, evaluated as percentage of neoplastic cells with cytoplasmic immunoreactivity, in a wide cohort of patients with stage I NSCLC (136 cases). The median value of this series (20% of positive cells) was used as the cutoff value to distinguish tumours with low (<20%) from tumours with high (⩾20%) OPN expression. A statistically significant correlation between high levels of OPN and shorter overall (P=0.034) and disease-free (P=0.011) survival in our patients was shown. Our results support the hypothesis that high OPN expression is a significantly unfavourable prognostic factor for the survival of patients with stage I NSCLC. This conclusion has notable importance in terms of the biological characterization of early-stage tumours and therapeutic opportunities

    Soluble Serum CD81 Is Elevated in Patients with Chronic Hepatitis C and Correlates with Alanine Aminotransferase Serum Activity

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    Aim: Cellular CD81 is a well characterized hepatitis C virus (HCV) entry factor, while the relevance of soluble exosomal CD81 in HCV pathogenesis is poorly defined. We performed a case-control study to investigate whether soluble CD81 in the exosomal serum fraction is associated with HCV replication and inflammatory activity. Patients and Methods: Four cohorts were investigated, patients with chronic hepatitis C (n = 37), patients with chronic HCV infection and persistently normal ALT levels (n = 24), patients with long term sustained virologic response (SVR, n = 7), and healthy volunteers (n = 23). Concentration of soluble CD81 was assessed semi-quantitatively after differential centrifugation ranging from 200 g to 100,000 g in the fifth centrifugation fraction by immunoblotting and densitometry. Results: Soluble CD81 was increased in patients with chronic hepatitis C compared to healthy subjects (p = 0.03) and cured patients (p = 0.017). Patients with chronic HCV infection and persistently normal ALT levels and patients with long term SVR had similar soluble CD81 levels as healthy controls (p>0.2). Overall, soluble CD81 levels were associated with ALT levels (r = 0.334, p = 0.016) and severe liver fibrosis (p = 0.027). Conclusion: CD81 is increased in the exosomal serum fraction in patients with chronic hepatitis C and appears to be associated with inflammatory activity and severity of fibrosis

    Analysis of Thyroid Response Element Activity during Retinal Development

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    Thyroid hormone (TH) signaling components are expressed during retinal development in dynamic spatial and temporal patterns. To probe the competence of retinal cells to mount a transcriptional response to TH, reporters that included thyroid response elements (TREs) were introduced into developing retinal tissue. The TREs were placed upstream of a minimal TATA-box and two reporter genes, green fluorescent protein (GFP) and human placental alkaline phosphatase (PLAP). Six of the seven tested TREs were first tested in vitro where they were shown to drive TH-dependent expression. However, when introduced into the developing retina, the TREs reported in different cell types in both a TH-dependent and TH-independent manner, as well as revealed specific spatial patterns in their expression. The role of the known thyroid receptors (TR), TRα and TRβ, was probed using shRNAs, which were co-electroporated into the retina with the TREs. Some TREs were positively activated by TR+TH in the developing outer nuclear layer (ONL), where photoreceptors reside, as well as in the outer neuroblastic layer (ONBL) where cycling progenitor cells are located. Other TREs were actively repressed by TR+TH in cells of the ONBL. These data demonstrate that non-TRs can activate some TREs in a spatially regulated manner, whereas other TREs respond only to the known TRs, which also read out activity in a spatially regulated manner. The transcriptional response to even simple TREs provides a starting point for understanding the regulation of genes by TH, and highlights the complexity of transcriptional regulation within developing tissue
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