Numerical Analysis for the Oxidation of Phenol with TiO2 in Wastewater Photocatalytic Reactors

Phenolic compounds in wastewater (even at low levels) are found to be quite toxic to humans due to their carcinogenic effects. Photocatalysis has been widely studied for the removal of phenol from industrial wastewater. In this study, photocatalytic oxidation of phenol, under UV irradiation in the presence of TiO2, has been numerically investigated. Phenol mass balance and forward finite difference method (explicit) along with various assumed/calculated parameters, from previous works, were used to numerically plot phenol concertation profiles in water with different initial phenol concentrations. Phenol compounds were observed to be totally oxidized at the bottom of the reactor and the maximum conversion rates occur near the reactor walls. It was found that higher irradiation times increase phenol oxidation rates due to higher water hydrolysis. Oxidation rate of phenol (consumption) increases with the increase in initial phenol concentration

Segmentation of corpus callosum using diffusion tensor imaging: validation in patients with glioblastoma

Abstract Background This paper presents a three-dimensional (3D) method for segmenting corpus callosum in normal subjects and brain cancer patients with glioblastoma. Methods Nineteen patients with histologically confirmed treatment naïve glioblastoma and eleven normal control subjects underwent DTI on a 3T scanner. Based on the information inherent in diffusion tensors, a similarity measure was proposed and used in the proposed algorithm. In this algorithm, diffusion pattern of corpus callosum was used as prior information. Subsequently, corpus callosum was automatically divided into Witelson subdivisions. We simulated the potential rotation of corpus callosum under tumor pressure and studied the reproducibility of the proposed segmentation method in such cases. Results Dice coefficients, estimated to compare automatic and manual segmentation results for Witelson subdivisions, ranged from 94% to 98% for control subjects and from 81% to 95% for tumor patients, illustrating closeness of automatic and manual segmentations. Studying the effect of corpus callosum rotation by different Euler angles showed that although segmentation results were more sensitive to azimuth and elevation than skew, rotations caused by brain tumors do not have major effects on the segmentation results. Conclusions The proposed method and similarity measure segment corpus callosum by propagating a hyper-surface inside the structure (resulting in high sensitivity), without penetrating into neighboring fiber bundles (resulting in high specificity)

Arcuate Fasciculus Abnormalities and Their Relationship with Psychotic Symptoms in Schizophrenia

Disruption of fronto-temporal connections involving the arcuate fasciculus (AF) may underlie language processing anomalies and psychotic features such as auditory hallucinations in schizophrenia. No study to date has specifically investigated abnormalities of white matter integrity at particular loci along the AF as well as its regional lateralization in schizophrenia. We examined white matter changes (fractional anisotropy (FA), axial diffusivity (AD), asymmetry indices) along the whole extent of the AF and their relationship with psychotic symptoms in 32 males with schizophrenia and 44 healthy males. Large deformation diffeomorphic metric mapping and Fiber Assignment Continuous Tracking were employed to characterize FA and AD along the geometric curve of the AF. Our results showed that patients with schizophrenia had lower FA in the frontal aspects of the left AF compared with healthy controls. Greater left FA and AD lateralization in the temporal segment of AF were associated with more severe positive psychotic symptoms such as delusions and hallucinations in patients with schizophrenia. Disruption of white matter integrity of the left frontal AF and accentuation of normal left greater than right asymmetry of FA/AD in the temporal AF further support the notion of aberrant fronto-temporal connectivity in schizophrenia. AF pathology can affect corollary discharge of neural signals from frontal speech/motor initiation areas to suppress activity of auditory cortex that may influence psychotic phenomena such as auditory hallucinations and facilitate elaboration of delusional content

Computation of metallic nanofluid natural convection in a two-dimensional solar enclosure with radiative heat transfer, aspect ratio and volume fraction effects

As a model of nanofluid direct absorber solar collectors (nano-DASCs), the present article describes recent numerical simulations of steady-state nanofluid natural convection in a two-dimensional enclosure. Incompressible laminar Newtonian viscous flow is considered with radiative heat transfer. The ANSYS FLUENT finite volume code (version 19.1) is employed. The enclosure has two adiabatic walls, one hot (solar receiving) and one colder wall. The Tiwari-Das volume fraction nanofluid model is used and three different nanoparticles are studied (Copper (Cu), Silver (Ag) and Titanium Oxide (TiO2)) with water as the base fluid. The solar radiative heat transfer is simulated with the P1 flux and Rosseland diffusion models. The influence of geometrical aspect ratio and solid volume fraction for nanofluids is also studied and a wider range is considered than in other studies. Mesh-independence tests are conducted. Validation with published studies from the literature is included for the copperwater nanofluid case. The P1 model is shown to more accurately predict the actual influence of solar radiative flux on thermal fluid behaviour compared with Rosseland radiative model. With increasing Rayleigh number (natural convection i.e. buoyancy effect), significant modification in the thermal flow characteristics is induced with emergence of a dual structure to the circulation. With increasing aspect ratio (wider base relative to height of the solar collector geometry) there is a greater thermal convection pattern around the whole geometry, higher temperatures and the elimination of the cold upper zone associated with lower aspect ratio. Titanium Oxide nano-particles achieve slightly higher Nusselt number at the hot wall compared with Silver nano-particles. Thermal performance can be optimized with careful selection of aspect ratio and nano-particles and this is very beneficial to solar collector designers

Preparation of Bio-Inspired Melanin Nanoplatforms Chelated with Manganese Ions as a Potential T1 MRI Contrast Agent

Commercial contrast agents demonstrated release risk of the toxic gadolinium ions, and designing of highly stable complexes of biogenic element such as Mn is challenging. In this contribution, Mn-melanin nanoparticles have been prepared and reacted with m-PEG. The effect of initial amount of Mn ions on the Mn absorption and its release by melanin nanoparticles (MNP) has been investigated. It has been found that MNP absorb and release more Mn ion by increasing the initial amount of Mn ions. It has been found that time and temperature has no significant effect on Mn absorption by MNP. It is found that the hydrodynamic size of MNP is in accordance with size of MNP which measured with TEM analysis (5.5±2 nm) and the effect of chain of m-PEG and conformational alteration of MNP is responsible of hydrodynamic size variation. The zeta potential of MNP is decreased by PEGylation and reaction with Mn ions. MNP�Mn-PEG demonstrated low toxicity up to 3.45 mg/mL after 24 h for human embryonic kidney cells. Finally, the r1 value of MNP�Mn-PEG is 10 fold higher than Dotarem as the commercial MRI contrast agent which can be administrated at much lower doses to achieve similar contrast of Dotarem. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei

Adult choledochal cysts in 23 patients: a brief report

Background: Choledochal cyst is a congenital disease of hepatobiliary system. Patients with the disease differ in terms of gender and symptoms. In this study, we aimed to evaluate the patients from clinical signs and symptoms, diagnostic methods and treatment perspectives.Methods: In this retrospective study, we evaluated the data from the medical records of patients with choledochal cyst admitted in Ghaem and Omid hospitals affiliated to Mashhad University of Medical Sciences in Mashhad, Iran during 1994 to 2011.Results: The medical records of 23 (18 women and 5 men) patients were evaluated. The mean age of the patients was 24.6 years. The most common type of the disease was choledochal cyst type 1. The most common type of surgery performed in the patients, respectively was resection of biliary cyst, cholecystectomy and Roux-en-Y hepaticojejunostomy. No mortality was observed during the hospital stay or follow-up period. Surgical complications were minor and patients recovered by conservative measures.Conclusion: Regarding the favorable results of surgical treatment of choledochal cysts, timely and definite diagnosis of this congenital anomaly and proper planning for its surgery are of special importance