290 research outputs found

    Controlling the Density of Plasma Species in Ar/CF4 Radiofrequency Capacitively Coupled Plasma Discharges

    Full text link
    In this manuscript, a fluid model is utilized to calculate the density of plasma species assuming geometrically symmetric Ar/CF4 Radiofrequency Capacitively Coupled Plasmas. The electrodes are driven by a sinusoidal waefront with an amplitude of 200 V and a frequency of 13.56 MHz. The gap between the electrodes is 5cm. The plasma species density is calculated as a function of the gas pressure, electron temperature, and the gas composition. In a good agreement with recent experimental results, CF3+CF^+_3 and F are dominant for all considered simulation parameters. The results explain the pathways to perform atomic layer etching and nanolayer deposition processes. In order to reveal the effect of electron heating on the discharge dynamics, The spatiotemporal electron energy equation is coupled to the fluid model. Tailoring the driven potential has been found to control the concentration of some plasma species. When the plasma is driven with the fundamental frequency, Ohmic and stochastic heating allows electrons to be heated symmetrically. Higher harmonics give rise to an electrical asymmetry and electron heating asymmetry between the powered and grounded sheaths. The electron temperature depends on the driven harmonics; it adjusts gain and loss rates and some plasma species densities

    Repeatability of Corneal Elevation Maps in Keratoconus Patients Using the Tomography Matching Method

    Get PDF
    To assess repeatability of corneal tomography in successive measurements by Pentacam in keratoconus (KC) and normal eyes based on the Iterative Closest Point (ICP) algorithm. The study involved 143 keratoconic and 143 matched normal eyes. ICP algorithm was used to estimate six single and combined misalignment (CM) parameters, the root mean square (RMS) of the difference in elevation data pre (PreICP-RMS) and post (PosICP-RMS) tomography matching. Corneal keratometry, expressed in the form of M, J0 and J45 (power vector analysis parameters), was used to evaluate the effect of misalignment on corneal curvature measurements. The PreICP-RMS and PosICP-RMS were statistically higher (P < 0.01) in KC than normal eyes. CM increased significantly (p = 0.00), more in KC (16.76 ± 20.88 μm) than in normal eyes (5.43 ± 4.08 μm). PreICP-RMS, PosICP-RMS and CM were correlated with keratoconus grade (p < 0.05). Corneal astigmatism J0 was different (p = 0.01) for the second tomography measurements with misalignment consideration (−1.11 ± 2.35 D) or not (−1.18 ± 2.35 D), while M and J45 kept similar. KC corneas consistently show higher misalignments between successive tomography measurements and lower repeatability compared with healthy eyes. The influence of misalignment is evidently clearer in the estimation of astigmatism than spherical curvature. These higher errors appear correlated with KC progression

    Comparative DNA Analysis of Solid Tumors by Flow Cytometric and Image Analyses of Touch Imprints and Flow Cell Suspensions

    Get PDF
    Comparative DNA analysis by flow cytometric (FCM) and image analyses (IA) has shown a high concordance rate. When present, discordance has been attributed to the presence of aneuploid cell populations detected only by IA, yet missed by FCM. This phenomenon has been explained by loss of aneuploid cells during FCM cell processing, differences in sampling area, or misinterpretation of the DNA histograms. To determine which factors are responsible for the discordance between IA and FCM, 82 fresh solid tumors from various sites were examined. Flow cytometric analysis was performed on cell suspensions isolated from the tumors, whereas IA was performed on touch imprints (IAT) and on cytosmears of the same cell suspension used for FCM (IAF). Comparison between IAT and IAF (IAT/IAF) assessed cell processing and sampling area differences, whereas IAF/FCM comparison assessed differences in apparatus and methodology as possible contributing factors to discordance. Furthermore, DNA histograms of IAT, IAF, and FCM were analyzed in the discordant cases to determine whether the discordance was due primarily to different cell populations detected (true discordance) or due to differences in histogram interpretation of the same cell populations (false discordance). IAT/IAF and IAF/FCM concordance rates (90% and 88%) were not significantly different from that of IAT/FCM (87%). False discordance accounted for most of the discordant cases in IAT/FCM comparison (six cases, 67%), whereas true discordance was seen in three cases. In all three truly discordant cases, the DNAaneuploid cell populations detected only by IAT yet missed by FCM were also detected by IAF. This study demonstrates that discordance between IA and FCM is probably not due to cell loss during FCM cell processing or sampling area differences, but may be due to differences in assessing DNA ploidy in the interpretation of IA histograms and/or dilution of aneuploid cells by normal diploid cells in FCM

    Impact of drying on techno-functional and nutritional properties of food proteins and carbohydrates - A comprehensive review

    Get PDF
    This is the final version. Available on open access from Taylor & Francis via the DOI in this recordData availability statement: There is no data available for this article.Foods comprise of many macromolecules that have varying techno-functional and nutritional properties. The isolated proteins and carbohydrates from them are increasingly being used as potential ingredients in the food industries. Numerous processes like drying for food processing and preservation cause variations in functional and nutritional attributes of proteins and carbohydrates in different degrees in the food products that can ultimately affect their possible applications. This article explores different drying technologies being used in the food industries, including freeze-drying, microwave-assisted drying, infrared drying, vacuum drying, spray drying, and oven drying. Based on the evaluation of multiple studies, it can be inferred that these drying methods have the potential to contribute to low drying performance, high operational costs, and strong environmental impact. Moreover, they can affect the nutritional value of macronutrients such as proteins, starches, gums, and dietary fibers present in foods, the integrity of the food structures, and their functional properties. Understanding the correlation between the drying technique used and the functional and nutritional attributes of macromolecules will help to provide better insight into the importance of the different drying methods. Optimization of the operational parameters of the different drying methods could be vital and needs to be evaluated to avoid the degradation of the proteins and carbohydrates and the loss of their properties

    Use of quercetin in animal feed : effects on the P-gp expression and pharmacokinetics of orally administrated enrofloxacin in chicken

    Get PDF
    Modulation of P-glycoprotein (P-gp, encoded by Mdr1) by xenobiotics plays central role in pharmacokinetics of various drugs. Quercetin has a potential to modulate P-gp in rodents, however, its effects on P-gp modulation in chicken are still unclear. Herein, study reports role of quercetin in modulation of P-gp expression and subsequent effects on the pharmacokinetics of enrofloxacin in broilers. Results show that P-gp expression was increased in a dose-dependent manner following exposure to quercetin in Caco-2 cells and tissues of chicken. Absorption rate constant and apparent permeability coefficient of rhodamine 123 were decreased, reflecting efflux function of P-gp in chicken intestine increased by quercetin. Quercetin altered pharmacokinetic of enrofloxacin by decreasing area under curve, peak concentration, and time to reach peak concentration and by increasing clearance rate. Molecular docking shows quercetin can form favorable interactions with binding pocket of chicken xenobiotic receptor (CXR). Results provide convincing evidence that quercetin induced P-gp expression in tissues by possible interaction with CXR, and consequently reducing bioavailability of orally administered enrofloxacin through restricting its intestinal absorption and liver/kidney clearance in broilers. The results can be further extended to guide reasonable use of quercetin to avoid drug-feed interaction occurred with co-administered enrofloxacin or other similar antimicrobials.Peer reviewedFinal Published versio

    Effect of dust storm intensity variations on total path attenuation prediction

    Get PDF
    This paper proposes a novel dust-storm total path attenuation prediction model. This model is formulated as a function of specific attenuation (dB/km) and the effective distance, which considers the non-uniform dust storm intensity variations throughout the link. The effective distance is obtained as a combination of the total link distance and the reduction factor. The reduction factor is developed based on the modeled 2-D structure of the observed dust storm characteristics. A measurement campaign of atmospheric characteristics, their properties, and effects on several microwave links operated in Khartoum-Sudan was conducted. In an earlier report, an empirical dust storm attenuation prediction model was proposed based on short-distance links by assuming uniform dust storm intensity variations. However, it was observed that the dust intensity varies with the distance, which affects total attenuation, and this issue is not addressed yet. One year measurement on the 6.2 km and 7.6 km long microwave links operating at 21.2 GHz and 14.5 GHz are used to validate the proposed dust storm total path attenuation model

    Phase II Open Label Study of Valproic Acid in Spinal Muscular Atrophy

    Get PDF
    UNLABELLED:Preliminary in vitro and in vivo studies with valproic acid (VPA) in cell lines and patients with spinal muscular atrophy (SMA) demonstrate increased expression of SMN, supporting the possibility of therapeutic benefit. We performed an open label trial of VPA in 42 subjects with SMA to assess safety and explore potential outcome measures to help guide design of future controlled clinical trials. Subjects included 2 SMA type I ages 2-3 years, 29 SMA type II ages 2-14 years and 11 type III ages 2-31 years, recruited from a natural history study. VPA was well-tolerated and without evident hepatotoxicity. Carnitine depletion was frequent and temporally associated with increased weakness in two subjects. Exploratory outcome measures included assessment of gross motor function via the modified Hammersmith Functional Motor Scale (MHFMS), electrophysiologic measures of innervation including maximum ulnar compound muscle action potential (CMAP) amplitudes and motor unit number estimation (MUNE), body composition and bone density via dual-energy X-ray absorptiometry (DEXA), and quantitative blood SMN mRNA levels. Clear decline in motor function occurred in several subjects in association with weight gain; mean fat mass increased without a corresponding increase in lean mass. We observed an increased mean score on the MHFMS scale in 27 subjects with SMA type II (p<or=0.001); however, significant improvement was almost entirely restricted to participants <5 years of age. Full length SMN levels were unchanged and Delta7SMN levels were significantly reduced for 2 of 3 treatment visits. In contrast, bone mineral density (p<or=0.0036) and maximum ulnar CMAP scores (p<or=0.0001) increased significantly. CONCLUSIONS:While VPA appears safe and well-tolerated in this initial pilot trial, these data suggest that weight gain and carnitine depletion are likely to be significant confounding factors in clinical trials. This study highlights potential strengths and limitations of various candidate outcome measures and underscores the need for additional controlled clinical trials with VPA targeting more restricted cohorts of subjects. TRIAL REGISTRATION:ClinicalTrials.gov

    Update to the College of American Pathologists Reporting on Thyroid Carcinomas

    Get PDF
    Background The reporting of thyroid carcinomas follows the recommendations of the College of American Pathologists (CAP) protocols and includes papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary carcinoma. Despite past and recent efforts, there are a number of controversial issues in the classification and diagnosis of thyroid carcinomas (TC) that, potentially impact on therapy and prognosis of patients with TC. Discussion The most updated version of the CAP thyroid cancer protocol incorporates recent changes in histologic classification as well as changes in the staging of thyroid cancers as per the updated American Joint Commission on Cancer staging manual. Among the more contentious issues in the pathology of thyroid carcinoma include the defining criteria for tumor invasiveness. While there are defined criteria for invasion, there is not universal agreement in what constitutes capsular invasion, angioinvasion and extrathyroidal invasion. Irrespective of the discrepant views on invasion, pathologists should report on the presence and extent (focal, widely) of capsular invasion, angioinvasion and extrathyroidal extension. These findings assist clinicians in their assessment of the recurrence risk and potential for metastatic disease. It is beyond the scope of this paper to detail the entire CAP protocol for thyroid carcinomas; rather, this paper addresses some of the more problematic issues confronting pathologists in their assessment and reporting of thyroid carcinomas. Conclusion The new CAP protocol for reporting of thyroid carcinomas is a step toward improving the clinical value of the histopathologic reporting of TC. Large meticulous clinico-pathologic and molecular studies with long term follow up are still needed in order to increase the impact of microscopic examination on the prognosis and management of TC

    Fast preparation route to high-performances textured Sr-doped Ca 3 Co 4 O 9 thermoelectric materials through precursor powder modification

    Get PDF
    This work presents a short and very efficientmethod to produce high performance textured Ca3Co4O9thermoelectric materials through initial powders modifica-tion. Microstructure has shown good grain orientation, andlow porosity while slightly lower grain sizes were obtained insamples prepared from attrition milled powders. All samplesshow the high density of around 96% of the theoretical value.These similar characteristics are reflected in, approximately,the same electrical resistivity and Seebeck coefficient valuesfor both types of samples. However, in spite of similar powerfactor (PF) at low temperatures, it is slightly higher at hightemperature for the attrition milled samples. On the otherhand, the processing time reduction (from 38 to 2 h) whenusing attrition milled precursors, leads to lower mechanicalproperties in these samples. All these data clearly point out tothe similar characteristics of both kinds of samples, with adrastic processing time decrease when using attrition milledprecursors, which is of the main economic importance whenconsidering their industrial production
    corecore