Numerical Study of Diodicity Mechanism in Different Tesla-Type Microvalves

AbstractMicrovalve is one of the most important components in microfluidic systems and micropumps. In this paper, three-dimensional incompressible flow through a Tesla-type microvalve is simulated using FLUENT computational fluid dynamic package. The flow is laminar and SIMPLE algorithm is used. The second-order upwind method is implemented for discretizing convective terms. The diodicity mechanism is investigated in detail for three different microvalves. Effect of several series Tesla-type microvalves on diodicity is also studied. The numerical analyses reveal that the mechanism of diodicity occurs at the T-junction and side channel. If inlet and outlet channels are eliminated, diodicity can be increased by 2. Pressure field analysis shows that the pressure drop is much severe at the junction of the reverse flow compared to the forward flow. The obtained numerical results are compared with those of experimental and a good agreement between them is noticed

Adding wheat and rapeseed meal to corn-soy diets affects intestinal morphology and nutrient digestibility in broilers

This study was conducted to investigate the effects of thyme essential oil and enzyme supplementation on rations with two different energy (wheat or corn) and protein resources (soy or rapeseed meals) on gut morphology and protein digestibility of broiler chickens. Three hundred eighty-four male Ross-308 broiler chickens were used with a 23 factorial arrangement with treatments according to a completely randomized design. The morphological examinations of the intestine were carried out on 1-cm long excised segments from duodenum, jejunum and ileum. Adding wheat to the diet increased small intestine length in birds compared to other feedstuffs (P <0.05). Duodenum crypt depth and jejunum villi length were also higher in groups fed with rations containing wheat (P <0.05). Groups that received thyme essential oil and enzyme supplementation had increased length of the duodenum (P <0.05). However, the two- and three-factor interaction effects were not significant. Protein digestibility was not affected by treatment (P >0.05). Feeding wheat to broiler chickens may increase the surface area for nutrient absorption in the small intestine as compensation for the anti-nutritive activity of non-starch polysaccharides in wheat-based diets. Wheat based diets are expected to be acceptable for broilers when supplemented with appropriate enzymes or thyme essential oil

Influence of the counter anion and steric hindrance of pyrazolyl and imidazolyl flexible ligands on the structure of zinc-based coordination polymers

Treatments of flexible 1,4-bis(3,5-dimethylpyrazolyl)butane (bbd), 1,4-bis(imidazolyl)butane (bib) and 1,4-bis(2-methylimidazolyl)butane (bmib) ligands with zinc salts at room temperature, resulted in the formation of four novel metal\u2013organic coordination architectures: [ZnI2(l-bbd)]n (1), [Zn(NCS)2(l-bbd)]n (2), {[Zn(l-bib)2](ClO4)2 (Et2O)0.5 (H2O)0.25}n (3) and {[Zn(l-bmib)2](ClO4)2 (H2O)4}n (4). X-ray crystallographic analyses show different 1D and 3D polymeric structures for compounds 1\u20134 due to the variation of the counter anions, solvent, steric hindrance and position of donating atoms in the structure of flexible ligands. In 1 and 2, one-dimensional (1D) zig-zag polymeric chains are formed via metal centers and l-bbd ligands. Complex 3 shows a 3-fold interpenetrated 3D architecture with 10^3-ths network topology. In contrast to 3, in the structure of 4 neighboring Zn(II) ions are interconnected by a double-bridging l-bmib ligands to form an infinite 1D polymeric double chain. The conformations of the flexible ligands were analyzed in detail

Three Cationic: Nonporous CuI-Coordination Polymers: Structural Investigation and Vapor Iodine Capture

Three cationic nonporous copper(I) coordination polymers containing bis-pyrazolyl flexible ligands have been prepared and characterized, namely, [Cu(\u3bc-bdb)1.5](PF6)n (1), [Cu(\u3bc-bpb)2](PF6)n (2), and [Cu(\u3bc-bpmb)2](PF6)n (3) (bdb = 1,4-bis(3,5-dimethylpyrazolyl) methyl)benzene; bpb = 1,4-bis(pyrazolyl)butane; bpmb = 1,4-bis(pyrazolyl)methyl)benzene). All compounds were characterized by infrared, powder X-ray diffraction, elemental and thermal analyses, and single-crystal X-ray diffraction. Compound 1, with methyl-substituted pyrazolyl ligand, forms a chain of alternating rings and ribbons in which the copper(I) centers are three coordinated in distorted trigonal planar geometry. In compounds 2 and 3 copper(I) atoms adopt distorted tetrahedral geometries giving two-dimensional sheet structures with 44-sql topology. Interestingly, iodine sorption experiments show that colorless crystals of 2 and 3 remain unchanged in the presence of iodine vapors, while the three-coordinated compound 1 immediately absorbs iodine and turns dark. Anion exchange behavior of compounds 1 and 2 was also investigated both in solution and in the solid state

Multi-locus sequence type analysis of Shigellas pp. Isolates from Tehran, Iran

Background and Objectives: Strains of Shigella spp. can cause shigellosis, or bacillary dysentery. That is a public health problem worldwide. The aim of this study was to describe the population structure and genetic relatedness of multidrug resistant S. sonnei and S. flexneri isolated during a one year period from children with diarrhea in Tehran, Iran. Materials and Methods: A total of 70 Shigella spp. were detected during the study period. Twenty MDR isolates of Shigella spp. were randomly selected and used in this study. Bacterial identification was performed by conventional biochemical and serological and confirmed by molecular method. After antimicrobial susceptibility testing, we used Multilocus sequence typing (MLST) for subtyping isolates. Results: We found 14 Shigella sonnei and 6 Shigella flexneri isolates. Results of MLST showed five sequence types (ST) (145, 152, 241, 245, 1502) and BURST analysis revealed the largest number of single locus variant (SLV) and highest frequency (FREQ) for ST152. ST 152 with nine members was predicted as the founder by BURST. Frequency for ST 1502 and ST 245 was four isolates and the least frequency was seen for ST 241 and 145 with one and two members, respectively. ST 145 and ST 245 were described as singletons in BURST. All isolates with ST145 and ST245 were identified as Shigella flexneri. Conclusion: Annual Multi locus sequence typing of MDR Shigella would help us in better understanding of dominant species and comparing our results with the same studies in other countries especially our neighbor countries in source tracking purposes. © Tehran University of Medical Science. All rights reserved

Prevalence of chronic kidney disease and its associated risk factors: The first report from Iran using both microalbuminuria and urine sediment

Background: The incidence of major risk factors of chronic kidney disease (CKD) in the world is on the rise, and it is expected that this incidence and prevalence, particularly in developing countries, will continue to increase. Using data on urinary sediment and microalbuminuria, we aimed to estimate the prevalence of CKD in northeast Iran. Methods: In a cross-sectional study, the prevalence of CKD in a sample of 1557 regionally representative people, aged � 18 years, was analyzed. CKD was determined based on glomerular filtration rate (GFR) and microalbuminuria. Life style data, urine and blood samples were collected. Urine samples without any proteinuria in the initial dipstick test were checked for qualitative microalbuminuria. If the latter was positive, quantitative microalbuminuria was evaluated. Results: 1557 subjects with a mean age of 56.76 ± 12.04 years were enrolled in this study. Based on the modifcation of diet in renal disease (MDRD) equation, 137 subjects (8.89%) were categorized as CKD stages III-V. Based on urine abnormalities, the prevalence of combined CKD stages I and II was 10.63%, and based on macro- and microalbuminuria it was 14.53%. The prevalence of CKD was significantly associated with sex, age, marital status, education, diabetes mellitus (DM), hypertension (HTN), ischemic heart disease (IHD), waist to hip ratio, myocardial infarction (MI), and cerebrovascular accident (CVA). Conclusion: CKD and its main risk factors are common and represent a definite health threat in this region of Iran. Using and standardizing less expensive screening tests in low resource countries could be a good alternative that may improve the outcome through early detection of CKD

The effect of intrathecal delivery of bone marrow stromal cells on hippocampal neurons in rat model of Alzheimer�s disease

Objective(s): Intracerebral injection of bone marrow stromal cells (BMSCs) is being investigated as a therapeutic tool to prevent Alzheimer's disease (AD). Our aim was to investigate the effects of BMSCs by intrathecal injection in AD rat model. Materials and Methods: BMSCs were obtained from the bone marrow of Wistar rat and transplanted into AD rat model via intrathecal injection. The rat model had received an injection of � amyloid into the hippocampus for histological and immunohistochemical studies. Results: Histological examination of the brains in transplanted rats compared to controls demonstrated the migration of BrdU-labeled BMSCs from the site of delivery, confirmed the differentiation of BMSCs transplanted cells into the cholinergic neurons, and increased number of healthy and decreased number of dark neurons. Conclusion: Our results showed that BMSCs intratechal administration could be a promising method for treatment of Alzheimer�s disease in rat model. © 2015, Iranian Journal of Basic Medical Sciences. All rights reserved