Ultrastructural Islet Study of Early Fibrosis in the Ren2 Rat Model of Hypertension Emerging Role of the Islet Pancreatic Pericyte-Stellate Cell

Type 2 diabetes mellitus is a multifactorial disease with polygenic and environmental stressors resulting in multiple metabolic toxicities and islet oxidative stress. We have integrated the role of the islet renin-angiotensin system (RAS) in the pathogenesis of early islet fibrosis utilizing the transgenic (mRen2)27 rodent model of hypertension and tissue RAS overexpression. The Ren2 pancreatic islet tissue was evaluated with transmission electron microscopy to study both early cellular and extracellular matrix remodeling. Major remodeling differences in the Ren2 model were found to be located within the islet exocrine interface, including deposition of early fibrillar-banded collagen (fibrosis) and cellular remodeling of the pericyte suggesting proliferation, migration, hypertrophy and activation as compared to the Sprague Dawley controls.This research was supported by the investigator initiated grants NIH (R01 HL73101-01A1), the Veterans Affairs Merit System (0018) grant and Novartis Pharmaceuticals. Male transgenic Ren2 rats and male Sprague-Dawley controls were kindly provided by Dr. Carlos M. Ferrario, Wake Forest University School of Medicine, Winston-Salem, North Carolina through the Transgenic Core Facility supported in part by NIH grant HL-51952

Adaptive Lagrangian–Eulerian computation of propagation and rupture of a liquid plug in a tube

Liquid plug propagation and rupture occurring in lung airways can have a detrimental effect on epithelial cells. In this study, a numerical simulation of a liquid plug in an infinite tube is conducted using an Eulerian–Lagrangian approach and the continuous interface method. A reconstruction scheme is developed to allow topological changes during plug rupture by altering the connectivity information about the interface mesh. Results prior to the rupture are in reasonable agreement with the study of Fujioka et al . in which a Lagrangian method is used. For unity non‐dimensional pressure drop and a Laplace number of 1000, rupture time is shown to be delayed as the initial precursor film thickness increases and rupture is not expected for thicknesses larger than 0.10 of tube radius. During the plug rupture process, a sudden increase of mechanical stresses on the tube wall is recorded, which can cause tissue damage. The peak values of those stresses increase as the initial precursor film thickness is reduced. After rupture, the peaks in mechanical stresses decrease in magnitude as the plug vanishes and the flow approaches a fully developed behavior. Increasing initial pressure drop is shown to linearly increase maximum variations in wall pressure and shear stress. Decreasing the pressure drop and increasing the Laplace number appear to delay rupture because it takes longer for a fluid with large inertial forces to respond to the small pressure drop. Copyright © 2010 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88023/1/2422_ftp.pd

A new model for predicting the grain size of electrodeposited nanocrystalline nickel coatings containing sulphur, phosphorus or boron based on typical systems

Controlling the grain size in electrodeposited coatings for the prevention of corrosion is highly important. To understand the relationship with grain size and electrochemical performance many experiments need to be undertaken to vary the grain size of the deposit. In the present work the (crystallite) grain size of electrodeposited Ni coatings formed in the presence of metalloids such as boron (B), sulphur (S) and phosphorus (P) was estimated from analysing mass transfer at the cathode-electrolyte interface. A mathematical model has been proposed which indicates that the grain size of the deposit is directly proportional to current efficiency and the deposition rate while being inversely proportional to the current density and metalloid (B, S, P) content in the coatings. A simple relationship is developed which is in agreement with experimental data and data that is reported in the literature. The development of such a model should significantly decrease the amount of experimentation required to achieve the desired grain size in such systems (Ni-B, Ni-S, Ni-P coatings) obtained by electrodeposition

FRICTION STIR WELDING OF AA6063- EXPERIMENTATION AND TESTING

Generally, for joining process for soft materials such as aluminum alloys and also for hard materials like steels friction stir welding is usedas it avoids many of the common problems obtained in fusion welding. Also if we gone through joining of aluminum alloys could be usually faced problems in many cases available in various fields like automotive, aerospace, ship building industries, electronics etc. where fusion welding is not possible due to large difference in physical and chemical properties of the components to be joined. Mainly the problems occurred in the welding processes like porosity formation, solidification cracking, and chemical reaction may arise during fusion welding of dissimilar materials. Even if good welded joints may be obtained in some limited cases with special attentions to the joint design and preparation, process parameters and filler metals

Effect of addition of different reinforcements on the microstructure and mechanical characterization of the Al-Flyash composites

The aim of this work is to investigate the influence of the addition of silicon carbide and molybdenum disulfide on the microstructure and the tensile strength of the Al-Flyash hybrid composites prepared using the stir casting technique. The composite with aluminum 6061 alloy as the matrix and flyash as the reinforcement, with different weight fractions, is investigated to study its microstructure and the tensile strength. The same has been compared with the hybrid composites with Aluminum-Flyash/SiC and Aluminum-Flyash/MoS2 for different weight fractions of the reinforcements. The tensile tests were conducted as per ASTM standard testing procedures at room temperature. From the results it is identified that tensile strength of the Al6061-Flyash composite is lesser than the Al6061-Flyash/SiC and Al6061-Flyash/MoS2 hybrid composites. It is also observed that increment in the composition of the SiC and MoS2 causes the increment in the tensile strength of the hybrid composite. This increment in the tensile strength is due to good interface bonding and uniform distribution of the reinforcements in the composite

Mechanical properties, thermal stability and corrosion behavior of electrodeposited Ni-B/AlN nanocomposite coating

The present study focuses on the development of Ni-B alloy AlN nanocomposite coating employing a novel electrodeposition technique from citrate bath. The influence of incorporation of AlN particles on structure, thermal stability and mechanical properties of Ni-B alloy coatings has been studied. The addition of AlN particles resulted in improved hardness, elastic modulus of Ni-B coatings by 52% and 46% respectively but also resulted in lower thermal stability. The nanocomposite Ni-B-AlN coatings illustrated increased corrosion protection efficiency over their Ni-B counterpart by a factor of 3.Authors are thankful to Qatar University , Doha, Qatar for funding and supporting the execution of this research.Scopu