Using Experiential and Collaborative Learning to Promote Careers in Engineering

This paper discusses the design of the Girls Accelerating and Learning STEM (G.A.L.S.) one-week residential summer camp designed to encourage young girls to pursue engineering careers. Specifically, the camp exposed participants to the fields of computer science and engineering using experiential learning to develop participant interest and skills. At the end of the program, students participated in team competitions and presented their work. The end-of-program survey data showed that the G.A.L.S. camp had an impact on the enhancement of student interest in engineering as a potential career. The paper will provide details on the program components, and further discuss the impacts of the program and how it can be used as a model for future programs.Cockrell School of Engineerin

Membrane synthesis for produced water filtration

Oil and gas exploration and production yields produced water (PW) which contains metal and oil. High volumes of PW pose threats to the public and environment, creating a major ecological problem. Forward Osmosis and membrane technology have been at the forefront as a pretreatment before discharge and as an option to remove oil contaminates in PW filtrate so that it can be used for other processes. Fabricated membranes are investigated for their effectiveness and efficiency in produced water filtration. Poly (vinyl) alcohol (PVA) /polysulfone (PSf) composite membranes with silver nanoparticle prevent microbial foulant accumulation during filtration. Functionalized composite membranes with a spacing element (1,4-butanediol diglycidal ether (1,4-BDE)) and metal chelating ligand(s) (iminodiacetic acid (IDA), nitrilotriacetic acid (NTA) or N-(2-hydroxyethyl) ethylenediamine N-N’-N’ triacetic acid (HEDT)) bind metals present in the PW. Enzymes (membrane monooxygenase, soluble rubredoxin, rubredoxin reductase and alkane hydroxylases) have been shown to treat contaminated soils therefore enzymes within the membrane via glutaraldehyde crosslinking will be shown to breakdown the hydrocarbon contaminated water. Preliminary data for composite PVA/PSf membrane show promising results for PW filtration with maintaining flux while preventing fouling

Investigation of biofouling resistant poly(vinyl alcohol)/cellulose acetate ultrafiltration membranes

Biofouling is detrimental to water filtration processes and decreases the durability of membranes. Therefore, membranes, that are resistant to the accumulation of microorganisms, are a necessity for water filtration. In this study, Cellulose Acetate (CA) and Poly(vinyl alcohol) blend membranes were prepared by the phase inversion method. To increase the rejection of foulants through the membrane, silver (Ag+) was added then reduced (Ag0) to decrease metal leaching. The casting solution consisted of 15% (w/v) polymer and 85% (w/v) N-Methyl 2-Pyrrolidone. Of the 15% (w/v) polymer concentration, different PVA concentrations were compared: 2% (w/v) 5% (w/v) and 10% (w/v). The membranes were analyzed for metal attachment, protein rejection, and water/foulant flux. Membranes were characterized with FTIR, XPS, SEM and Serial Dilution. FTIR confirmed the presence of the PVA’s hydroxyl group and a decrease in the intensity of the CA’s carbonyl group when blended. Additionally, membranes blended with PVA efficiently reduce adsorption of protein onto the membrane surface. Reduced silver membranes efficiently eradicate the growth of E.coli over a 5-hour time span pending E.coli colony concentration. SEM micrographs indicated differences in pore morphology with PVA while EDS confirms the presence of silver on membrane surface and sublayer. The water flux data displayed a great disparity when comparing CA membranes to PVA/CA membranes with a dramatic increase when blended with a surface modifier. Furthermore, a 28% increase in rejection was observed with the blended polymer

Evaluating alternative crosslinking agents in poly(vinyl alcohol) hydrogels membranes

Hydrogels are a network of polymer chains with properties that absorb, store and transport solutions. A hydrogel membrane has a permeability that allows influx and excretion. Therefore, it is the ideal material for medicated membranes. This study investigates the crosslinking of poly(vinyl alcohol) (PVA) hydrogel membranes using different agents and explores the usability of the candidate membranes as drug delivery systems. The model protein, bovine albumin serum (BSA), was used to test the stability and controlled drug release rate characteristics of the candidate hydrogel membranes. This investigation also evaluated the stability different crosslinkers for hydrogel membranes. Glutaraldehyde (GA) and an alternative crosslinking method of ultraviolet irradiation with the sensitizer, sodium benzoate (SB), were used to crosslink PVA containing BSA. In GA crosslinked membranes, BSA release diffusion experiments showed 48%, 45%, and 63% recovery of protein at pH 6.5, 7.4 and 8.0, respectively; this confirmed that this system is suited for physiological conditions and controlled release. Although SB has been used for membrane fabrication, our Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) results indicate that UV(SB)-crosslinked films are not suited for drug delivery, despite the release of BSA

Mucin pattern reflects the origin of the adenocarcinoma in Barrett's esophagus: a retrospective clinical and laboratorial study

<p>Abstract</p> <p>Background</p> <p>Mucin immunoexpression in adenocarcinoma arising in Barrett's esophagus (BE) may indicate the carcinogenesis pathway. The aim of this study was to evaluate resected specimens of adenocarcinoma in BE for the pattern of mucins and to correlate to the histologic classification.</p> <p>Methods</p> <p>Specimens were retrospectively collected from thirteen patients who underwent esophageal resection due to adenocarcinoma in BE. Sections were scored for the grade of intestinal metaplasia. The tissues were examined by immunohistochemistry for MUC2 and MUC5AC antibodies.</p> <p>Results</p> <p>Eleven patients were men. The mean age was 61 years old (varied from 40 to 75 years old). The tumor size had a mean of 4.7 ± 2.3 cm, and the extension of BE had a mean of 7.7 ± 1.5 cm. Specialized epithelium with intestinal metaplasia was present in all adjacent mucosas. Immunohistochemistry for MUC2 showed immunoreactivity in goblet cells, while MUC5AC was extensively expressed in the columnar gastric cells, localizing to the surface epithelium and extending to a variable degree into the glandular structures in BE. Tumors were classified according to the mucins in gastric type in 7/13 (MUC5AC positive) and intestinal type in 4/13 (MUC2 positive). Two tumors did not express MUC2 or MUC5AC proteins. The pattern of mucin predominantly expressed in the adjacent epithelium was associated to the mucin expression profile in the tumors, p = 0.047.</p> <p>Conclusion</p> <p>Barrett's esophagus adenocarcinoma shows either gastric or intestinal type pattern of mucin expression. The two types of tumors developed in Barrett's esophagus may reflect the original cell type involved in the malignant transformation.</p

Expanding the Number of ‘Druggable’ Targets: Non‐Enzymes and Protein–Protein Interactions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95062/1/cbdd.12066.pd

Development and Characterization of Membranes with PVA Containing Silver Particles: A Study of the Addition and Stability

Developing technologies for the reduction of biofouling and enhancement of membrane functionality and durability are challenging but critical for the advancement of water purification processes. Silver (Ag) is often used in the process of purification due to its anti-fouling properties; however, the leaching of this metal from a filtration membrane significantly reduces its effectiveness. Our study was designed to integrate the positive characteristics of poly vinyl alcohol (PVA) with the controlled incorporation of nano-scale silver ions across the membrane. This approach was designed with three goals in mind: (1) to improve antifouling activity; (2) to prevent leaching of the metal; and (3) to extend the durability of the functionalized membrane. The fabrication method we used was a modified version of manual coating in combination with sufficient pressure to ensure impregnation and proper blending of PVA with cellulose acetate. We then used the spin coater to enhance the cross-linking reaction, which improved membrane durability. Our results indicate that PVA acts as a reducing agent of Ag+ to Ag0 using X-ray photoelectron spectroscopy analysis and demonstrate that the metal retention was increased by more than 90% using PVA in combination with ultraviolet-photo-irradiated Ag+ reduced to Ag0. The Ag+ ions have sp hybrid orbitals, which accept lone pairs of electrons from a hydroxyl oxygen atom, and the covalent binding of silver to the hydroxyl groups of PVA enhanced retention. In fact, membranes with reduced Ag displayed a more effective attachment of Ag and a more efficient eradication of E. coli growth. Compared to pristine membranes, bovine serum albumin (BSA) flux increased by 8% after the initial addition of Ag and by 17% following ultraviolet irradiation and reduction of Ag, whereas BSA rejection increased by 10% and 11%, respectively. The implementation of this hybrid method for modifying commercial membranes could lead to significant savings due to increased metal retention and membrane effectiveness. These enhancements would ultimately increase the membrane&rsquo;s longevity and reduce the cost/benefit ratio

Characterization of PVA-IDA Hydrogel Crosslinked with 1.25%, 2.5% and 5% Glutaraldehyde

Hydrogel membranes continue to be investigated forpotential use in a number of applications includingbioseparations, water purification, controlled drug release, toname a few. The potential of hydrogels to overcomedisadvantages typically associated with packed bedchromatography such as low protein loading, elution conditionsand regeneration increase their potential applicability and use forbiological separations. However, these materials typically providelimited selectivity between proteins of similar size, low proteinloading and durability. To overcome these limitations, poly vinylalcohol (PVA) hydrogels were functionalized with metal affinityligand to provide a selective means to enhance protein loadingand improve protein separation characteristics. Additionally, thecrosslink ratio was varied from 1.25 % (v/v) to 5.0 % (v/v) tofurther enhance membrane selectivity while also increasingmembrane durability. Characterization and comparison ofmembranes with varied degrees of crosslinking and examinationof structural properties and behaviors of membranes weredetermined for this study. Atomic Absorption Spectroscopy(AAS), Fourier Transform Infrared spectroscopy (FTIR), andScanning Electron Microscopy (SEM) were used to characterizeand to examine IMAH membranes after functionalization.Results demonstrate successful functionalization of the poly vinylalcohol membrane with metal affinity ligands. The FTIR resultsshowed different band frequencies for specific groups associatedwith PVA cross-linked with glutaraldehyde. The presence of thechelator did not impact the swelling properties of the membrane;however, the Bound Copper Content (BCC) was increased by50%for the IDA-Me2+ membranes as the crosslinking ratio increasedfrom 1.25% to 5% GA (v/v).Moreover, an increase in cross-linking ratio resulted in structuralchanges that enhanced copper attachment which increasedprotein solubility

Osmotically Driven Membrane Processes - Approach, Development and Current Status

Osmotically driven membrane processes (ODMPs) including forward osmosis (FO) and pressure-retarded osmosis (PRO) have attracted increasing attention in fields such as water treatment, desalination, power generation, and life science. In contrast to pressure-driven membrane processes, e.g., reverse osmosis, which typically employs applied high pressure as driving force, ODMPs take advantages of naturally generated osmotic pressure as the sole source of driving force. In light of this, ODMPs possess many advantages over pressure-driven membrane processes. The advantages include low energy consumption, ease of equipment maintenance, low capital investment, high salt rejection, and high water flux. In the past decade, over 300 academic papers on ODMPs have been published in a variety of application fields. The number of such publications is still rapidly growing. The ODMPs' approach, fabrications, recent development and applications in wastewater treatment, power generation, seawater desalination, and gas absorption are presented in this book