167 research outputs found

    A Fractal Model for Capillary Pressure of Porous Media

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    Abstract: Capillary pressure is a basic parameter in the study of the behavior of porous media containing two or more immiscible fluid phases. In this study, the capillary pressure of porous media is predicted based on based on fractal property of pore in porous media. The formula of calculating the capillary pressure of porous media is given. The capillary pressure of porous media is expressed as a function of porosity, fractal dimension of pore and saturation. Based on the parametric effect analysis, we conclude that the capillary pressure of porous media is negatively correlated with the porosity and saturation. Besides, it is shown that the capillary pressure of unsaturated porous media decreases with the increase of saturation. No additional empirical constant is introduced. This model contains less empirical constants than the conventional correlations. The model predictions are compared with the existing experimental data and good agreement between the model predictions and experimental data is found. The validity of the present fractal model is thus verified

    Immunogenicity and Protective Efficacy against Murine Tuberculosis of a Prime-Boost Regimen with BCG and a DNA Vaccine Expressing ESAT-6 and Ag85A Fusion Protein

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    Heterologous prime-boost regimens utilizing BCG as a prime vaccine probably represent the best hope for the development of novel tuberculosis (TB) vaccines. In this study, we examined the immunogenicity and protective efficacy of DNA vaccine (pcD685A) expressing the fusion protein of Ag85A and ESAT-6 (r685A) and its booster effects in BCG-immunized mice. The recombinant r685A fusion protein stimulated higher level of antigen-specific IFN-γ release in tuberculin skin test- (TST-) positive healthy household contacts of active pulmonary TB patients than that in TST-negative population. Vaccination of C57BL/6 mice with pcD685A resulted in significant protection against challenge with virulent Mycobacterium tuberculosis H37Rv when compared with the control group. Most importantly, pcD685A could act as a BCG booster and amplify Th1-type cell-mediated immunity in the lung of BCG-vaccinated mice as shown the increased expression of IFN-γ. The most significant reduction in bacterial load of both spleen and lung was obtained in mice vaccinated with BCG prime and pcD685A DNA booster when compared with BCG or pcD685A alone. Thus, our study indicates that pcD685A may be an efficient booster vaccine against TB with a strong ability to enhance prior BCG immunity

    TiAVox: Time-aware Attenuation Voxels for Sparse-view 4D DSA Reconstruction

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    Four-dimensional Digital Subtraction Angiography (4D DSA) plays a critical role in the diagnosis of many medical diseases, such as Arteriovenous Malformations (AVM) and Arteriovenous Fistulas (AVF). Despite its significant application value, the reconstruction of 4D DSA demands numerous views to effectively model the intricate vessels and radiocontrast flow, thereby implying a significant radiation dose. To address this high radiation issue, we propose a Time-aware Attenuation Voxel (TiAVox) approach for sparse-view 4D DSA reconstruction, which paves the way for high-quality 4D imaging. Additionally, 2D and 3D DSA imaging results can be generated from the reconstructed 4D DSA images. TiAVox introduces 4D attenuation voxel grids, which reflect attenuation properties from both spatial and temporal dimensions. It is optimized by minimizing discrepancies between the rendered images and sparse 2D DSA images. Without any neural network involved, TiAVox enjoys specific physical interpretability. The parameters of each learnable voxel represent the attenuation coefficients. We validated the TiAVox approach on both clinical and simulated datasets, achieving a 31.23 Peak Signal-to-Noise Ratio (PSNR) for novel view synthesis using only 30 views on the clinically sourced dataset, whereas traditional Feldkamp-Davis-Kress methods required 133 views. Similarly, with merely 10 views from the synthetic dataset, TiAVox yielded a PSNR of 34.32 for novel view synthesis and 41.40 for 3D reconstruction. We also executed ablation studies to corroborate the essential components of TiAVox. The code will be publically available.Comment: 10 pages, 8 figure

    Determination of ramosetron in rat plasma by LC-ESI-MS and its application

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    A sensitive and simple liquid chromatography/electrospray mass spectrometry (LC-ESI-MS) method for determination of ramosetron in rat plasma using one-step protein precipitation was developed and validated. After addition of midazolam as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. Chromatographically separation was achieved on an SB-C18 (2.1 mm × 150 mm, 5 μm) column with acetonitrile-0.1 % formic acid as the mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantification using target fragment ions m/z 280 for ramosetron and m/z 326 for the IS. Calibration plots were linear over the range of 10-1000 ng/mL for ramosetron in rat plasma. Lower limit of quantification (LLOQ) for Ramosetron was 10 ng/mL. Mean recovery of ramosetron from plasma was in the range of 88.5-92.8 %. CV of intra-day and inter-day precision were both less than 15 %. This method is simple and sensitive enough to be used in pharmacokinetic study for determination of ramosetron in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Transcranial direct current stimulation regulates phenotypic transformation of microglia to relieve neuropathic pain induced by spinal cord injury

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    ObjectiveNeuropathic pain is a common complication after spinal cord injury (SCI). Transcranial direct current stimulation (tDCS) has been confirmed to be effective in relieving neuropathic pain in patients with SCI. The aim of this study is to investigate the effect of tDCS on neuropathic pain induced by SCI and its underlying mechanism.Materials and methodsThe SCI model was induced by a clip-compression injury and tDCS stimulation was performed for two courses (5 days/each). The motor function was evaluated by Basso-Beattie-Bresnahan (BBB) score, and the thermal withdrawal threshold was evaluated by the thermal radiation method. The effects of tDCS on the cerebral cortex, thalamus, midbrain, and medulla were detected by the enzyme-linked immunosorbent assay (ELISA) and immunofluorescence.ResultsThe results showed that SCI reduced the thermal withdrawal threshold and increased the concentration of inflammatory cytokines in the cortex, thalamus, midbrain, and medulla, including the tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). In addition, the activation of microglia and the proportion of M1 phenotypic polarization increased significantly in the ventral posterolateral (VPL), ventral tegmental (VTA), and periaqueductal gray (PAG) regions after SCI. After tDCS treatment, the thermal withdrawal threshold and motor function of SCI rats were significantly improved compared to the vehicle group. Meanwhile, tDCS effectively reduced the concentration of pro-inflammatory cytokines in the cortex, thalamus, midbrain, and medulla and increased the concentration of anti-inflammatory cytokines interleukin-10 (IL-10) in the thalamus. In addition, tDCS reduced the proportion of the M1 phenotype of microglia in VPL, VTA, and PAG regions and increase the proportion of the M2 phenotype.ConclusionThe results suggest that tDCS can effectively relieve SCI-induced neuropathic pain. Its mechanism may be related to regulating the inflammatory and anti-inflammatory cytokines in corresponding brain regions via promoting the phenotypic transformation of microglia

    The mediating effect of resilience on mental health literacy and positive coping style among Chinese empty nesters: A cross-sectional study

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    ObjectivesEmpty nesters in China have limited mental health literacy (MHL), which may lead to poorer health outcomes. Studies demonstrate that MHL is associated with both resilience and positive coping style. However, the potential mechanism of MHL, resilience and positive coping style remain unclear. Therefore, the study aims to investigate the possible mediating role of resilience in the relationship between MHL and positive coping style.MethodIn this cross-sectional study, a total of 363 empty nesters from Huzhou, China were surveyed in 2022. The Chinese version of Mental Health Literacy Scale (C-MHLS), the Chinese version of 10-item Connor-Davidson Resilience Scale (CD-RISC-10) and the Simplified Coping Style Questionnaire (SCSQ-19) were used to assess MHL, resilience, and positive coping style, respectively.ResultsPositive coping style was significantly correlated with MHL and resilience, and MHL was positively correlated with resilience (p < 0.01). MHL can significantly and positively predict the positive coping style, and resilience played a partial intermediary role between MHL and positive coping style, with the intermediary effect of 77.36%.ConclusionThis study indicates that MHL not only directly affected positive coping style, but also indirectly influences positive coping style by increasing the resilience of empty nesters. The results provide an empirical evidence for the development of intervention programs to improve positive coping style directly and indirectly. Consequently, community health servicers should take targeted measures which focus on MHL and resilience as breakthrough points to stimulate positive coping style of empty nesters, and ultimately achieve their overall well-being

    Effect of Parental Migration on the Intellectual and Physical Development of Early School-Aged Children in Rural China

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    Abstract OBJECTIVE: The purpose of this study is to estimate the effect of parent migration on intellectual and physical development of early school-aged children in rural China. DESIGN: setting and participants: The present cross-sectional study participants were a subset from a controlled, cluster-randomized, double-blind trial. From October 2012 to September 2013, the offspring of women who participated in a large trial were examined in the present study. Wechsler intelligence scale for children (WISC-IV) in which validity and reliability were shown to be satisfactory was used to measure the intellectual function and trained anthropometrists measured weight and height of children using standard procedures. RESULTS: The mean difference of FSIQ scores between non-migration and both-parent migration groups was -3.68 (95%CI: -5.49, -1.87). After adjusting for the confounders, the mean difference of full-scale IQ between non-migration and both-parent migration group was -1.97 (95%CI: -3.92, -0.01), the mean differences of perceptual reasoning index and processing speed index were -2.41 (95%CI: -4.50, -0.31) and -2.39 (95%CI: -4.42, -0.35) between two groups respectively. CONCLUSION: Our results emphasized the impairment of both-parental migration in intellectual function (FSIQ, PRI, PSI) of children. These findings have important policy implications for the Chinese government to prevent the impairment of left-behind children. Further research is required to clarify the mechanisms by which both-parental migration influence the impairment in intellectual function of children

    Associations of B Vitamin-Related Dietary Pattern during Pregnancy with Birth Outcomes: A Population-Based Study in Northwest China

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    This study aimed to derive a maternal dietary pattern to explain the variation in B vitamins during pregnancy and to investigate this pattern in relation to birth outcomes. A total of 7347 women who gave birth to live newborns less than one year were included. Their dietary pattern during pregnancy was derived using the reduced-rank regression method with six B vitamins as response variables. Associations between dietary pattern score and birth weight, gestational age at delivery, birth weight Z score, low birth weight, preterm, and small-for-gestational-age (SGA) were estimated using generalised linear mixed models. We identified a high B-vitamin dietary pattern characterised by high intakes of animal foods, vegetables, fungi and algae, legumes, and low intakes of oils and cereals. Women in the highest quartile of this pattern score had newborns with a 44.5 g (95% CI: 13.8, 75.2 g) higher birth weight, 0.101 (95% CI: 0.029, 0.172) higher birth weight Z score, and 27.2% (OR: 0.728; 95% CI: 0.582, 0.910) lower risk of SGA than those in the lowest quartile. Our study suggested that adherence to the high B-vitamin dietary pattern during pregnancy was associated with a higher birth weight and a lower risk of SGA

    The Enhancing Effects of the Light Chain on Heavy Chain Secretion in Split Delivery of Factor VIII Gene

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    Coagulation factor VIII (FVIII) is secreted as a heterodimer consisting of a heavy chain (HC) and a light chain (LC), which can be expressed independently and reassociate with recovery of biological activity. Because of the size limitation of adeno-associated virus (AAV) vectors, a strategy for delivering the HC and LC separately has been developed. However, the FVIII HC is secreted 10–100-fold less efficiently than the LC. In this study, we demonstrated that the F309S mutation and enhanced B-domain glycosylations alone are not sufficient to improve FVIII HC secretion, which suggested a role of the FVIII LC in regulating HC secretion. To characterize this role of the FVIII LC, we compared FVIII HC secretion with and without the LC via post-translational protein trans-splicing. As demonstrated in vitro, ligation of the LC to the HC significantly increased HC secretion. Such HC secretion increases were also confirmed in vivo by hydrodynamic injection of FVIII intein plasmids into hemophilia A mice. Moreover, similar enhancement of HC secretion can also be observed when the LC is supplied in trans, which is probably due to the spontaneous association of the HC and the LC in the secretion pathway. In sum, enhancing the secretion of the FVIII HC polypeptide may require the proper association of the FVIII LC polypeptide in cis or in trans. These results may be helpful in designing new strategies to improve FVIII gene delivery

    Identification of Genome-Wide Variations among Three Elite Restorer Lines for Hybrid-Rice

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    Rice restorer lines play an important role in three-line hybrid rice production. Previous research based on molecular tagging has suggested that the restorer lines used widely today have narrow genetic backgrounds. However, patterns of genetic variation at a genome-wide scale in these restorer lines remain largely unknown. The present study performed re-sequencing and genome-wide variation analysis of three important representative restorer lines, namely, IR24, MH63, and SH527, using the Solexa sequencing technology. With the genomic sequence of the Indica cultivar 9311 as the reference, the following genetic features were identified: 267,383 single-nucleotide polymorphisms (SNPs), 52,847 insertion/deletion polymorphisms (InDels), and 3,286 structural variations (SVs) in the genome of IR24; 288,764 SNPs, 59,658 InDels, and 3,226 SVs in MH63; and 259,862 SNPs, 55,500 InDels, and 3,127 SVs in SH527. Variations between samples were also determined by comparative analysis of authentic collections of SNPs, InDels, and SVs, and were functionally annotated. Furthermore, variations in several important genes were also surveyed by alignment analysis in these lines. Our results suggest that genetic variations among these lines, although far lower than those reported in the landrace population, are greater than expected, indicating a complicated genetic basis for the phenotypic diversity of the restorer lines. Identification of genome-wide variation and pattern analysis among the restorer lines will facilitate future genetic studies and the molecular improvement of hybrid rice
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