129 research outputs found

    Fluid flow through deformation band

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    Cataclastic deformation bands, which are common in porous sandstone, have the potential to restrict fluid flow. Geological studies have shown that permeability of deformation band shear zones can be one to five orders of magnitude less than for the sandstone host rock. However, recent studies based on simplified analytical estimates have shown that fluid flow in jointed deformation bands may not be retarded since joints play an important role in conducting fluids. In this study, 2 dimensional finite element analysis (FEA) is used to simulate the total discharge flow rate through jointed deformations. Variations of single planar and conjugate jointed deformation bands are considered. The study includes a sensitivity analysis of joint aperture, joint and deformation band orientation, joint spacing, and deformation band thickness in order to evaluate the influence of these parameters on the total discharge flow rate via jointed deformation bands. This study also considers the influence of spatial distribution of deformation band, deformation band orientations, and deformation band continuity on fluid flow and provides the comparison with jointed deformation band to investigate whether joints still play a significant role --Abstract, page iii

    Recombinant TAT–gelonin fusion toxin: Synthesis and characterization of heparin/protamine‐regulated cell transduction

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    Protein toxins, such as gelonin, are highly desirable anti‐cancer drug candidates due to their unparalleled potency and repetitive reaction mechanism in inhibiting protein translation. However, for its potential application in cancer therapy, there remains the cell membrane barrier that allows permeation of only small molecules, which must be overcome. To address this challenge, we conjugated gelonin with a protein transduction domain (PTD), the TAT peptide, via genetic recombination. The chimeric TAT–gelonin fusion protein (TAT‐Gel) retained equipotent N ‐glycosidase activity yet displayed greater cell uptake than unmodified recombinant gelonin (rGel), thereby yielding a significantly augmented cytotoxic activity. Remarkably, TAT‐Gel displayed up to 177‐fold lower IC 50 (avg. 54.3 n M ) than rGel (avg. IC 50 : 3640 n M ) in tested cell lines. This enhanced cytotoxicity, however, also raised potential toxicity concerns due to the non‐selectivity of PTD in its mediated cell transduction. To solve this problem, we investigated the plausibility of regulating the cell transduction of TAT‐Gel via a reversible masking using heparin and protamine. Here, we demonstrated, both in vitro and in vivo , that the cell transduction of TAT‐Gel can be completely curbed with heparin and yet this heparin block can be efficiently reversed by the addition of protamine. This reversible tight regulation of the cell transduction of TAT‐Gel by heparin and protamine sheds light of possible application of TAT‐Gel in achieving a highly effective yet safe drug therapy for the treatment of tumors. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 409–419, 2015.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109572/1/jbma35188.pd

    Correlation model between mesostructure and gradation of asphalt mixture based on statistical method

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    Asphalt mixture has complex gradation and mesostructure. Accurate prediction of the relationship between gradation and mesostructure is of great significance for the establishment of mesostructure numerical simulation model and image-based gradation detection. In this paper, featurization, stepwise regression, econometric hypothesis test are utilized for establishing the predicting models. Firstly, asphalt mixtures with 64 kinds of gradation are scanned by Computed Tomography (CT) to obtain the mesostructure images; Then a series of mesostructure parameters of voids and aggregates are put forward. On this basis, the relationship model between gradation and mesostructure is established and verified by featurization and statistical modeling method. The results show that for predicting the passing percentage of the 4.75 mm sieve and the mean value of average distance between aggregate centroids for 9.5–4.75 mm aggregates, the prediction error of passing percentage is acceptable. It illustrates that the relationship model between gradation and mesostructure established by statistical method is effective, and it is significance for material design and testing under the condition of big data in the future

    Protease‐Activatable Hybrid Nanoprobe for Tumor Imaging

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108698/1/adfm201400419.pd

    Prevalence and Prognostic Significance of HPV in Laryngeal Squamous Cell Carcinoma in Northeast China

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    Background/Aims: Human papillomavirus (HPV) is an etiological risk factor for a subset of head and neck squamous cell carcinomas. HPV has been proven to be a powerful prognostic biomarker for oropharyngeal cancer, but its role in the larynx has not been explored in depth. Here, we sought to evaluate the prevalence and genotype distribution of HPV in patients with laryngeal squamous cell carcinoma (LSCC) in northeast China. Methods: HPV DNA in specimens from 211 patients diagnosed with LSCC was analyzed by the polymerase chain reaction and in situ hybridization, and p16 overexpression was evaluated by immunohistochemistry. p16 expression was scored positive if strong and diffuse nuclear and cytoplasmic staining was present in > 75% of tumor cells. Results: In this study, infection with HPV and p16 expression were not absolutely consistent. Among all patients, 132 (62.6%) were positive for HPV DNA (HPV+), while 23 (10.9%) were inconsistent for HPV and p16. Multivariate analysis indicated that HPV, but not p16, is an independent prognostic factor for overall survival in LSCC. Overall survival was significantly improved in HPV+ LSCC patients compared with the HPV-negative group (hazard ratio, 0.395; 95% confidence interval, 0.185–0.843; p = 0.016). Among the 132 HPV+ patients, 28 (21.2%) were HPV-16 single infection. Conclusion: This study indicates that HPV DNA is a more reliable surrogate marker than p16 for the prediction of survival in patients with LSCC

    Cerebrospinal fluid oligoclonal bands in Chinese patients with multiple sclerosis: the prevalence and its association with clinical features

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    BackgroundCerebrospinal fluid oligoclonal band (CSF-OCB) is an established biomarker in diagnosing multiple sclerosis (MS), however, there are no nationwide data on CSF-OCB prevalence and its diagnostic performance in Chinese MS patients, especially in the virtue of common standard operation procedure (SOP).MethodsWith a consensus SOP and the same isoelectric focusing system, we conducted a nationwide multi-center study on OCB status in consecutively, and recruited 483 MS patients and 880 non-MS patients, including neuro-inflammatory diseases (NID, n = 595) and non-inflammatory neurological diseases (NIND, n=285). Using a standardized case report form (CRF) to collect the clinical, radiological, immunological, and CSF data, we explored the association of CSF-OCB positivity with patient characters and the diagnostic performance of CSF-OCB in Chinese MS patients. Prospective source data collection, and retrospective data acquisition and statistical data analysis were used.Findings369 (76.4%) MS patients were OCB-positive, while 109 NID patients (18.3%) and 6 NIND patients (2.1%) were OCB-positive, respectively. Time from symptom onset to diagnosis was significantly shorter in OCB-positive than that in OCB-negative MS patients (13.2 vs 23.7 months, P=0.020). The prevalence of CSF-OCB in Chinese MS patients was significantly higher in high-latitude regions (41°-50°N)(P=0.016), and at high altitudes (>1000m)(P=0.025). The diagnostic performance of CSF-OCB differentiating MS from non-MS patients yielded a sensitivity of 76%, a specificity of 87%.InterpretationThe nationwide prevalence of CSF-OCB was 76.4% in Chinese MS patients, and demonstrated a good diagnostic performance in differentiating MS from other CNS diseases. The CSF-OCB prevalence showed a correlation with high latitude and altitude in Chinese MS patients

    Roles of Mineralogical Phases in Aqueous Carbonation of Steelmaking Slag

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    Mineralogical phases of steelmaking slags have significant influences on the carbonation of the slags. In this paper, the effects of temperature and reaction time on the conversion of calcium-related phases and the carbonation degree of a slag sample were studied. The experimental conditions were a liquid-to-solid ratio of 20 mL/g, a carbon dioxide flow rate of 1 L/min and a slag particle size of 38–75 μm. The results show that the optimum carbonation temperature and reaction time are 60 °C and 90 min, respectively, and calcite phase content is about 26.78% while the conversion rates of Ca3Al2O6, CaSiO3, Ca2SiO4 and free CaO are about 40%, 42.46%, 51% and 100%, respectively, and the carbon dioxide sequestration efficiency is about 170 g/kg slag

    Spectrophotometric pH Measurements of Surface Seawater at In-situ Conditions: Absorbance and Protonation Behavior of Thymol Blue

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    The proton exchange behavior of thymol blue (HI− ⇔ I2− + H+) and the molar absorbance characteristics of unprotonated (I2−) and protonated (HI−) forms of this indicator make thymol blue particularly well suited to pH observations in the upper ocean. In-situ Spectrophotometric measurements of seawater pH using sulfonephthalein indicators require assessment of the influence of temperature on indicator molar absorbance characteristics and the influence of temperature and salinity on indicator equilibrium characteristics. Our investigation of the physical/chemical behavior of thymol blue indicates that seawater pH can be described using the following equation: pHT= pK2+ log(R − e1e2− R · e3) \u3epHT= pK2+ log(R − e1e2− R · e3) where pHT = − log[H+]T, [H+]T = [H+] + [HSO4−], K2− [H+]T[I2−][HI−]−, R =596A435A \u3eK2− [H+]T[I2−][HI−]−, R =596A435A (where λA is absorbance at wavelength λ), and pK2= 4.706ST+ 26.3300 − 7.172181ogT − 0.017316 × S \u3epK2= 4.706ST+ 26.3300 − 7.172181ogT − 0.017316 × S e1= − 0.00132 + 1.600 × 10−5Te2 = 7.2326 − 0.0299717T+ 4.600 × 10−5 T2e3 = 0.0223 + 0.0003917 T Using the equations given above, K2 and [H+]T are expressed in units of molkg-soln \u3emolkg-soln
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