Effect of Differences in the Primary Structure of the A-Chain on the Aggregation of Insulin Fragments

Bovine and human insulin have similar primary structures. In this article, the region of the insulin A-chain of bovine and human insulin where the amino acid composition is different was studied. Bovine insulin fragment (BIF) and human insulin fragment (HIF) were synthesized in solid-phase peptide synthesis. The effects of pH, temperature, urea, ionic strength, and stirring on the formation of fibrils were studied using a fractional factorial resolution III experimental design. Fibrillation was monitored by fluorescence and infrared spectroscopy and optical microscopy. Both fragments formed fibrils at pH 1.6 and a temperature of 60 °C. The lag time and apparent aggregation growth rate constant were determined using a two-parameter kinetic model. It was found that the bovine insulin fragment has a shorter lag time than the human insulin one, whereas the exponential phase rate was faster for HIF than for BIF. An increase in β-sheets content with time was observed in both fragments. The increase in β-sheets was preceded by an initial decrease in α-helices followed by an intermediate increase during the transition from the lag phase to elongation phase. Temperature and ionic strength are among the most important experimental factors during the lag phase, whereas ionic strength is replaced by pH during the elongation phase for both the fragments. Congo red binding confirmed the presence of ringlike oligomer structures rich in antiparallel β-sheets, which tend to form fibrils rich in parallel β-sheets

On One-dimensional Self-assembly of Surfactant-coated Nanoparticles

Nanometer-sized metal and semiconductor particles possess novel properties. To fully realize their potential, these nanoparticles need to be fabricated into ordered arrays or predesigned structures. A promising nanoparticle fabrication method is coupled surface passivation and self-assembly of surfactant-coated nanoparticles. Due to the empirical procedure and partially satisfactory results, this method still represents a major challenge to date and its refinement can benefit from fundamental understanding. Existing evidences suggest that the self-assembly of surfactant-coated nanoparticles is induced by surfactant-modified interparticle interactions and follows an intrinsic road map such that short one-dimensional (1D) chain arrays of nanoparticles occur first as a stable intermediate before further assembly takes place to form higher dimensional close-packed superlattices. Here we report a study employing fundamental analyses and Brownian dynamics simulations to elucidate the underlying pair interaction potential that drives the nanoparticle self-assembly via 1D arrays. We find that a pair potential which has a longer-ranged repulsion and reflects the effects of surfactant chain interdigitation on the dynamics is effective in producing and stabilizing nanoparticle chain arrays. The resultant potential energy surface is isotropic for dispersed nanoparticles but becomes anisotropic to favor the growth of linear chain arrays when self-assembly starts

Hogar Iglesia: Implementacion de un Programa para el Crecimiento de la Iglesia Adventista Hispana de Alexandria, Virginia

Problem. Alexandria church has not successfully executed a long-term program for small groups that achieved the involvement of members in missionary work. Throughout the years, it has not been able to establish a fixed growth rate for such involvement, which in turn should transform into a new lifestyle of testimony. When this strategy for small groups was implemented, there were significant results, however the program’s leaders became frustrated and skeptical after not being provided with a set plan for follow-up, solidification, and continuity. The purpose of this investigation was focused on developing and implementing a program for church growth, based on small groups, that rouses a unified and effective response in church members to accomplish healthy and steady increase not only in local membership, but also causes the establishment of new churches, and a spike in tithes. Consequentially, the small groups would not be merely a temporal strategy, but would also serve as a healthy new way of life for entire church, which wouldn’t be affected by pastoral rotations, or any other change in local leadership. The bibliographic revision required the extraction of similar situations by other authors. The Bible concepts and Ellen G. White’s writings were considered basic in this study. In reference to the detected ecclesiastical problem and the literary study, a church growth program based on the biblical model, known as “small groups” in the contemporary age, was developed. The program designed for and implemented in Alexandria Spanish SDA Church was titled “Home churches, a joyous experience.” Results. The plan was evaluated according to five variables: 1. The numeric growth of membership as a direct consequence of the home churches and discipleship program. Alexandria Spanish SDA church experienced an average growth of 207%. 2. The increase in tithes. A growth of 448% was achieved. 3. The establishment of new congregations. At least three new churches were founded. In 1996, after 40 year’s work, there were a total of 15 Spanish churches in the Potomac Conference territory. In 2006, after only 10 year’s work, that number grew to over 50 Spanish churches and congregations. 4. The number of Small Groups involved in Evangelism per year. An average of three to four evangelistic campaigns were held by each home church annually. This represented approximately 34 campaigns per home church, for a time of ten years. 5. The purchase of an adequate church building to definitively establish the church. This was achieved in October 2000

Situación de las principales enfermedades del cultivo de la soja en el período 2004/2005 - 2014/2015 en el Noroeste Argentino

En el Noroeste Argentino (NOA), el número de las patologías identificadas en el cultivo de soja y sus respectivos niveles de infección se fueron incrementando con los sucesivos años de cultivo. El uso de cultivares susceptibles, el monocultivo y la labranza cero, entre otros, son los principales factores que contribuyeron al incremento de estos problemas que se manifestaron con mayor severidad a partir de la década de 1990 (Ploper, 2004).Fil: González, Victoria. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: de Lisi, Vicente. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Reznikov, Sebastian. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina; ArgentinaFil: Aguaysol, Natalia C.. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Forciniti, Jorge. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Devani, Mario. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Ploper, Leonardo Daniel. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina; Argentin

A Blended Textbook-Free Chemical and Biochemical Process Safety Class

The Chemical Engineering Department of Missouri S&T has taught a chemical process safety class for more than twenty years. However, students pursuing a biochemical engineering emphasis program were not required to take that class. The department started a new curriculum two years ago that include a safety class for everyone. A new class was developed that includes elements of both chemical and biochemical process safety. There are several unique features of the new class that I would like to share: 1) it is offered in blended mode with two in class meetings per week followed by a series of online discussions; 2) it uses one of the design projects in senior design as a case study. Therefore, the material covered in class as well as the topics of the discussions are concentrated on a particular process; 3) a textbook is not required or recommended. Instead, the students use primary sources as well as information freely available on line published by various companies; and 4) this is a communications intensive class. The discussions are used to both improve the written communication skills of the students as well as to dig deep into a selected number of topics covering both chemical and biochemical processes. The discussions start with a brief posting about a manuscript that the students are asked to read. That is followed by a discussion that uses several prompts developed by the instructor. Student participation in the discussions have been excellent, providing valuable information to the class as well as to the instructor

Chemical Engineering at... Missouri S&T

One in a continuing series of profiles on chemical engineering departments

Industrial Bioseparations: Principles and Practice

Industrial Bioseparations offers comprehensive coverage of bioseparations including all unit operations. This new book offers a careful balance between the fundamentals of bioseparations processing and the practical applications in industry today. It is laid out in a methodical way with preliminary chapters covering general approaches to bioseparations for commercially important biomacromolecules, thermodynamics and mass transfer principles, and following chapters addressing unit operations such as filtration and chromatography. Lab experiments are included which emphasize obtaining scale up parameters as well as commonly used operating conditions are included

Surface Enrichment of Proteins at Quartz / Water Interfaces: A Neutron Reflectivity Study

Neutron reflectivity (NR) was used to study the adsorption of human serum albumin and human fibrinogen on quartz. The proteins were individually and sequentially adsorbed from heavy water and heavy water/methanol mixtures at pH 4 and 7.0. The technique allows for the subnanometer resolution of the adsorbed layer thickness and gross morphology. under the conditions of our measurements we found that fibrinogen formed a distinct layer that we interpret as a mat of the protein three layers thick whereas albumin formed only diffuse layers. The adsorption pattern of the two proteins changed radically when one protein was adsorbed on top of the other (previously adsorbed). In general our measurements indicate that the adsorbed protein layers on quartz are rather loosely bound and that these layers, incorporating as much as 80% water, extend further into the bulk fluid than might have been expected