Modeling of a microfluidic electrochemical cell for the electro-reduction of CO2 to CH3OH

This study focuses on developing a mathematical model for the electrochemical reduction of CO2 into CH3OH in a microfluidic flow cell. The present work is the first attempt to model the electro-reduction of CO2 to alcohols, which is a step forward toward the scale up of the process to industrial operation. The model features a simple geometry of a filter press cell in which the steady state isothermal reduction takes place. All significant physical phenomena occurring inside the cell are taken into account, including mass and charge balances and transport, fluid flow and electrode kinetics. The model is validated and fitted against experimental data and shows an average error of 20.2%. The model quantitatively demonstrated the dominance of the hydrogen evolution over the CH3OH production and the limitations imposed on the process due to the mass transfer of the reactants to the cathode, especially CO2. Also, the model shows that based on the flow pattern of CH3OH, more conductive membrane materials could be used to decrease the potential drop around the membrane in order to improve the process performance

Insertion/Deletion markers for assessing the genetic variation and the spatial genetic structure of Tunisian Brachypodium hybridum populations

The wild annual grass Brachypodium hybridum, an allotetraploid species derived from the natural hybridization between the diploid species B. distachyon (2n=10) and B. stacei (2n=20). This trio of species has been suggested as a model system for polyploidy. Brachypodium hybridum is the most widespread Brachypodium species in Tunisia. Natural diversity can be used as a powerful tool to uncover gene function and, in the case of B. hybridum, to understand the functional consequences of polyploidy. Here, we examined the spatial distribution of genetic variation of B. hybridum across its entire range in Tunisia and tested underlying factors that shaped its genetic variation. Population genetic analyses were conducted on 145 individuals from 9 populations using 8 InDel markers. Results indicated a relatively high level of within-population genetic diversity (He = 0.35) and limited among-population differentiation (FPT = 0.20) for this predominantly self-pollinating grass. UPGMA cluster analyses, PCoA and Bayesian clustering supported the demarcation of the populations into 3 groups that were not correlated with location or altitude, suggesting a loose genetic affinity of B. hybridum populations in relation to their geographical locations, and no obvious genetic structure among populations across the study area. This pattern was associated with a considerable amount of an asymmetric gene flow between populations. Overall, the obtained results suggest that the long-distance seed-dispersal is the most important factor in shaping the spatial genetic structure of B. hybridum in Tunisia. They also provide key guidelines for on-going and future work including breeding programs and genome-wide association studies

Numerical identification of classical and nonclassical moduli of 3D woven textiles and analysis of scale effects

International audienceHomogeneous anisotropic couple-stress continuum model as substitutes of 3D woven textiles are presently developed. The architecture of the considered fabric preforms is obtained from an idealized geometry and organization of the yarns within a representative unit cell. The effective properties are obtained based on the finite element response of the representative volume element (RVE) under prescribed boundary conditions. Specific boundary conditions including both traction and displacement boundary conditions are applied on the structure boundaries. The effective classical and nonclassical mechanical moduli are deduced by an equivalent strain energy method. The characteristic bending lengths are identified from the resulting homogenized moduli. We model 2D and 3D textiles either as a one phase solid (dry textiles), or as a two-phase material consisting of the set of yarns and a softer surrounding phase representing the resin. The effects of scale on the predicted classical and nonclassical moduli of these textiles are investigated by varying the size of the textile unit cell over which the boundary conditions are applied. The analysis delivers classical moduli that are independent of unit cell size, whereas the couple stress moduli depend on the cell size. The developed approach is quite general and applicable to any composite materials

Role of quantitative diffusion weighted

Purpose: To evaluate the diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant breast lesions. Patients and methods: Forty patients with positive diagnoses at mammography or breast ultrasound were included in this study. Patients were imaged with dynamic contrast enhanced MRI and DWI before biopsy of their breast tumors. Apparent diffusion coefficient (ADC) map was utilized to select the region of interest (ROI) for ADC calculation. DWI was performed using three sets of b value (0, 400, and 800 s/mm2). Results: The final analysis comprised 40 breast lesions, 18 of which were malignant and 22 were benign. Significant results were obtained between ADC values of benign and malignant lesions (p < 0.001). The cut-off ADC value for benign and malignant lesions was 1.25 × 10–3 mm2/s. Conclusion: The present study provides consistent evidence to support DWI as a diagnostic tool for breast lesion characterization and as a useful adjunct to standard breast MRI protocols in aiding the diagnosis of breast cancer

Complications of Port A Cath implantation: A single institution experience

Objectives: To determine the complications associated with Port A Cath insertion in cancer patients. Methods: The records 250 patients, who received a subcutaneous port catheter between 2009 and 2013, were analyzed retrospectively with regard to implantation complications and complications in the course of Port A Cath use. Results: The average duration over which the Port A Cath remained in place was 22 months. Postoperative complications occurred in 29 patients (11.6%); of these, 4 (1.6%) were perioperative and 25 (10%) were long-term complications. Perioperative complications were in the form of inadvertent arterial rupture. Long-term complications included the following: infection in 10 patients (4%), mechanical failure in 5 patients (2%), thrombosis in 4 patients (1.6%), suture disruption in 3 patients (1.2%), extravasation in 2 patients (0.8%), and catheter migration in one patient (0.4%). Conclusion: Port A Cath implantation is associated with some risk of serious complications. Care of the catheter and the patient should be maintained to decrease the risk of complications

Chemoembolization follow-up of hepatocellular carcinoma with diffusion-weighted MR imaging

Purpose: To assess the treatment response of hepatocellular carcinoma (HCC) after transarterial chemoembolization with diffusion weighted magnetic resonance (MR) imaging with a 1.5 T system. Materials and methods: Thirty patients with 30 HCC focal lesions were prospectively evaluated for early treatment response after transarterial chemoembolization using dynamic contrast enhanced MRI and diffusion weighted MRI before and after the procedure. Diameter of arterially enhancing portions and apparent diffusion coefficient (ADC) values of lesions were recorded. The significance of differences between ADC values of completely responding and partially responding lesions was calculated. Results: Tumor ADC value increased from 1.2 + 0.1 × 103 mm2/s to 1.49 + 0.3 × 103 mm2/s after treatment (p < 0.001). There was a significant positive correlation between the percent change in the mean ADC and the percent change in the diameter of the enhancing tumor tissue after chemoembolization. The best predictive cutoff value for differentiation between complete and partial response was 24% change in the mean ADC. Conclusion: Responding HCC lesions exhibited decreases in arterial enhancement and increases in ADC values. Percent change in the mean ADC values was predictive of response to chemoembolization

Value of central vein sign in discriminating multiple sclerosis plaques from other white matter lesions

Introduction: Susceptibility weighted (SW) magnetic resonance imaging (MRI) can visualize the vein/s around which multiple sclerosis (MS) plaques are centered. This study's purpose was to assess the ability of the central vein sign (CVS) to differentiate MS plaques from non MS white matter lesions (WMLs). Methods: Out of 18 patients, 9 had MS, 3 had systemic lupus erythematosus, 4 had hypertensive microangiopathy and 2 had Behcet’s disease. 3 T MRI examination was performed to obtain fluid attenuated inversion recovery (FLAIR) and the SW images. Lesions more than 3 mm were identified and analyzed for location and existence of the CVS. Results: Out of 572 MS lesions, 281 lesions were positive for the CVS, while only 66 out of 279 non MS lesions were CVS positive with a statistically significant difference between the two groups (p < 0.001). As regards the percentage of perivenous lesions per patient; using a cutoff value of 30%, MRI accurately segregated all patients with MS and 8/9 non MS patients. Conclusion: Though the CVS is not found solely in MS lesions it is more frequent in MS WMLs as compared to non MS WML and thus is reliable adjunctive tool in differentiation of MS plaques from WMLs of alternative etiologies. Keywords: Central vein sign, Multiple sclerosis, Susceptibility weighted imaging, White matter lesion

Adaptive differentiation among populations of the Mediterranean dry grassland species Brachypodium retusum : The role of soil conditions, grazing, and humidity

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Thymol-Loaded Eudragit RS30D Cationic Nanoparticles-Based Hydrogels for Topical Application in Wounds: In Vitro and In Vivo Evaluation

Natural medicines formulated using nanotechnology-based systems are a rich source of new wound-treating therapeutics. This study aims to develop thymol-loaded cationic polymeric nanoparticles (CPNPs) to enhance the skin retention and wound healing efficacy of thymol. The developed materials exhibited entrapment efficiencies of 56.58 to 68.97%, particle sizes of 36.30 to 99.41 nm, and positively charged zeta potential. In Vitro sustained release of thymol up to 24 h was achieved. Selected thymol CPNPs (F5 and C2) were mixed with methylcellulose to form hydrogels (GF5 and GC2). An In Vivo skin-retention study revealed that GF5 and GC2 showed 3.3- and 3.6-fold higher retention than free thymol, respectively. An In Vitro scratch-wound healing assay revealed a significant acceleration in wound closure at 24 h by 58.09% (GF5) and 57.45% (GC2). The potential for free thymol hydrogel, GF5, and GC2 to combat MRSA in a murine skin model was evaluated. The bacterial counts, recovered from skin lesions and the spleen, were assessed. Although a significant reduction in the bacterial counts recovered from the skin lesions was shown by all three formulations, only GF5 and GC2 were able to reduce the bacterial dissemination to the spleen. Thus, our study suggests that Eudragit RS30D nanoparticles-based hydrogels are a potential delivery system for enhancing thymol skin retention and wound healing activity