1,159 research outputs found
Kinetic characterization of the critical step in HIV-1 protease maturation
HIV maturation requires multiple cleavage of long polyprotein chains into functional proteins that include the viral protease itself. Initial cleavage by the protease dimer occurs from within these precursors, and yet only a single protease monomer is embedded in each polyprotein chain. Self-activation has been proposed to start from a partially dimerized protease formed from monomers of different chains binding its own N termini by self-association to the active site, but a complete structural understanding of this critical step in HIV maturation is missing. Here, we captured the critical self-association of immature HIV-1 protease to its extended amino-terminal recognition motif using large-scale molecular dynamics simulations, thus confirming the postulated intramolecular mechanism in atomic detail. We show that self-association to a catalytically viable state requires structural cooperativity of the flexible ÎČ-hairpin âflapâ regions of the enzyme and that the major transition pathway is first via self-association in the semiopen/open enzyme states, followed by enzyme conformational transition into a catalytically viable closed state. Furthermore, partial N-terminal threading can play a role in self-association, whereas wide opening of the flaps in concert with self-association is not observed. We estimate the association rate constant (k(on)) to be on the order of âŒ1 Ă 10(4) s(â1), suggesting that N-terminal self-association is not the rate-limiting step in the process. The shown mechanism also provides an interesting example of molecular conformational transitions along the association pathway
Assessment of Entrepreneurial Education and Diversity Management: a Gateway to Sustainable Development in Nigeria
The study assessed the contributions of entrepreneurship Education course in enhancing management/ entrepreneurial skills of informal entrepreneurs and diversity management. Informal entrepreneurs are those who passed through the technical/vocational schools and have certificates with which they are carrying out their entrepreneurship as a result of the fact that they are not able to move forward academically. Two research questions guided the study. The population, which was used as the sample for the study because of its small size, was 41 informal entrepreneurs in Delta North Senatorial District of Delta State. The instruments for data collection were a 140 item questionnaire. The mean was used for data analysis. Results showed that the entrepreneurship knowledge given to these informal entrepreneurs were adequate but are not re-enforced and some of the trade areas get less of what they are supposed to get. Attention also should be given to the technical aspect. The informal entrepreneurs in their fields of business have seen the entrepreneurship education as very important. Based on these, recommendations were made
Collaborative business process management through harmonized messaging
Workflow systems in specific and Business Process Management Technologies in general, have significantly contributed to overcoming some of the integration problems of intra and inter enterprise process control and monitoring. However, the complexity of the interactions between heterogeneous and autonomous systems with in the enterprise and often between trading partners in ever increasing. A number of initiatives and proposals are underway to provide solutions for process specification and communication. However, the focus is often on defining APIs and interfaces rather than the semantics of the underlying interactions. On the other hand messaging technologies are well positioned as the key enabling technology for facilitating these interactions. Although messaging systems have traditionally had a different agenda dominated by scalability and performance, we see a great potential in the enhancement of current messaging infrastructure, in its new role in facilitating complex, long running interactions for dynamic and collaborative processes operating in decentralized environments like the web. In this paper, we primarily present a vision for a technology aimed at providing a level of harmonization to multiple messages to form a single custom definable backbone. We will provide the foundation framework for the harmonized messaging technology and identify fundamental issues for the management of such complex interactions
Synthesis of new Polyimides Derived from 4- minoantipyrine
In the present study, new five polymers of acryloyl chloride have been synthesized by reaction 4-aminoantipyrine with many substituted acid chloride (A-E). Then condensation of polyacryloyl chloride with the product in one step (A-E), in a suitable solvent in the presence amount of (Et3N) to obtain new polyimides(A1-E5). The prepared compounds were characterized by UV. FT-IR, 1H-NMR and 13C-NMR spectroscopy and measuring of other physical properties such as softening point, melting point and solublities
Production and Economics Evaluation of Pilot Scale Essential Oil Extract from Eucalyptus Citriodora Leaves
In this study, essential oil was extracted from eucalyptus citriodora leaves plant species (lemon-scented gum) in a pilot plant using steam distillation technology. The extraction pattern of the oil was monitored over time and economic analysis of the production was carried out. Five batches were carried out in a day and the results revealed that the daily production of the oil was 0.579 liters in a loading capacity of 100kg of leaves. It was also observed that the total production cycle per batch was 1.96 hours out of which 80 minutes were the actual extraction time with lag period of 37 minutes. The results further revealed that 66.7% of the oil was extracted in 40 minutes while 95.6% in 80 minutes. Liquefied petroleum gas (LPG) was used as source of energy with daily consumption of 7.5 kg at a cost of N2,400.00K. The economic analysis on annual basis revealed that the operating cost was N1,742,400.00K. The production output of the oil was estimated at 138.96 litres with expected selling price of N4,863,600.00K at the rate of N35,000.00K per litre and expected profit after tax of N2,115,871.00K. From this economic analysis carried out based on the practical data generated in the pilot plant, this project is highly profitable and is strongly recommended to potential investors and entrepreneurs. This will help in providing jobs for our teaming unemployed youths mostly in rural areas where these raw materials are in abundant thereby increasing nationâs foreign earning due to its export potential
Generalized mean-field study of a driven lattice gas
Generalized mean-field analysis has been performed to study the ordering
process in a half-filled square lattice-gas model with repulsive nearest
neighbor interaction under the influence of a uniform electric field. We have
determined the configuration probabilities on 2-, 4-, 5-, and 6-point clusters
excluding the possibility of sublattice ordering. The agreement between the
results of 6-point approximations and Monte Carlo simulations confirms the
absence of phase transition for sufficiently strong fields.Comment: 4 pages (REVTEX) with 4 PS figures (uuencoded
Efficient Compliance Checking Using BPMN-Q and Temporal Logic
Abstract. Compliance rules describe regulations, policies and quality constraints business processes must adhere to. Given the large number of rules and their frequency of change, manual compliance checking can be-come a time-consuming task. Automated compliance checking of process activities and their ordering is an alternative whenever business pro-cesses and compliance rules are described in a formal way. This paper introduces an approach for automated compliance checking. Compliance rules are translated into temporal logic formulae that serve as input to model checkers which in turn verify whether a process model satisfies the requested compliance rule. To address the problem of state-space explo-sion we employ a set of reduction rules. The approach is prototypically realized and evaluated.
An Intervention to Increase Condom Use Among Users of Chlamydia Self-Sampling Websites (Wrapped): Intervention Mapping and Think-Aloud Study.
BACKGROUND: Young people aged 16-24 years are disproportionately affected by sexually transmitted infections (STIs). STIs can have serious health consequences for affected individuals and the estimated annual cost of treatment to the National Health Service is ÂŁ620 million. Accordingly, the UK government has made reducing the rates of STIs among this group a priority. A missed opportunity to intervene to increase condom use is when young people obtain self-sampling kits for STIs via the internet. OBJECTIVE: Our aim was to develop a theory-based tailored intervention to increase condom use for 16-24-years-olds accessing chlamydia self-sampling websites. METHODS: The intervention, Wrapped, was developed using Intervention Mapping and was co-designed with young people. The following steps were performed: (1) identification of important determinants of condom use and evidence of their changeability using computer and digital interventions; (2) setting the intervention goal, performance objectives, and change objectives; (3) identification of Behavior Change Principles (BCPs) and practical strategies to target these determinants; and (4) development of intervention materials able to deliver the BCPs and practical strategies. RESULTS: Users of existing chlamydia self-sampling websites are signposted to Wrapped after placing an order for a sampling kit. Salient barriers to condom use are identified by each user and relevant intervention components are allocated to target these. The components include the following: (1) a sample box of condoms, (2) an online condom distribution service, (3) a product for carrying condoms, (4) a condom demonstration video, (5) a series of videos on communication about condom use, and (6) erotic films of real couples discussing and demonstrating condom use. CONCLUSIONS: This intervention will be directed at young people who may be particularly receptive to messages and support for behavior change due to their testing status
Anisotropic dynamical scaling in a spin model with competing interactions
Results are presented for the kinetics of domain growth of a two-dimensional
Ising spin model with competing interactions quenched from a disordered to a
striped phase. The domain growth exponent are and for
single-spin-flip and spin-exchange dynamics, as found in previous simulations.
However the correlation functions measured in the direction parallel and
transversal to the stripes are different as suggested by the existence of
different interface energies between the ground states of the model. In the
case of single-spin-flip dynamics an anisotropic version of the
Ohta-Jasnow-Kawasaki theory for the pair scaling function can be used to fit
our data.Comment: 4 pages, REVTeX fil
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