OPTIMIZATION APPROACH FOR DESIGN OF SPUR GEAR BASED ON GENETIC ALGORITHM

Abstract -  The problem of designing spur gear with minimum mass and smaller size without violating the constraints plays a major role in today's industrial world, since the most commonly encountered mechanical power transmission require low weight. This paper presents an genetic approach to reduce the weight and thickness of the gear, also increases the power transmitting capacity and effectiveness using genetic algorithm (GA). It can be observed that the proposed optimal design with GA has the potential to yield considerably better solutions than the traditional heuristics. At the same time, the GA offer a better understanding of the trade-offs between various constraints.   Key words: Optimal design, genetic algorithm, Spur gea

Intelligent Microcontainers : Fabrication, Characterization And Tunable Release Properties For Drug Delivery

Polyelectrolyte capsules fabricated by layer-by-layer (LbL) technique are introduced as a simple and efficient carrier system for spontaneous deposition of proteins and low molecular water soluble drug. The objective of the work was to investigate the applicability of polyelectrolyte capsules as vehicles for sustained or controlled delivery of drugs. Two different polymeric systems composed of weak and strong polyelectrolytes were chosen to study the loading and release behavior in order to meet the requirements of biomedical applications. In the first system, the wall permeability of weak polyelectrolyte (PAH/PMA) capsules could be readily manipulated from open to closed state by simply varying the pH. The open and closed state of the capsules could be attributed to the charge density variation of weak polyelectrolytes, which induces the capsule wall to undergo a transition from continuous to nanoporous morphology due to phase segregation. Bovine Serum Albumin (BSA) was spontaneously deposited in the hollow capsules and deposition was investigated by CLSM, SEM and AFM techniques. The driving force for spontaneous deposition was electrostatic interaction between the preloaded polystyrene sulfonate (PSS) and BSA. The deposition was uniform and concentration of BSA in the capsule interior reached a few hundred times greater than that of bulk. The amount of loading was significantly influenced by the loading pH, loading concentration and charge density of substance to be loaded at the corresponding pH. The deposition was successful up to the isoelectric point of BSA (pH = 4.8) and there was no loading observed above that, since the deposition is based on electrostatic attraction between PSS and BSA. During the release at physiological pH of 7.4, charge reversal of BSA occurred which induced electrostatic repulsion between PSS and BSA thereby triggering the movement of BSA from the interior to the bulk. Release continued up to 5 h in water and a total release of 63 % was observed which increased to 72 % when release was performed in PBS. Spontaneous deposition of low molecular weight, water soluble drug, ciprofloxacin hydrochloride was performed in the same manner and its release profile was studied. Controlling diffusion of smaller drug molecules is extremely difficult in drug delivery applications. Cross linking of capsule wall components could be used to control the release rates of smaller drug molecules. Cross linking density is dependent on the cross linking time and increases the stiffness of the capsule wall. Release of ciprofloxacin hydrochloride was possible even up to 6 h after cross linking. Antibacterial studies showed that the drug released even after 25 h has a significant effect on the bacterial pathogen E.coli. The second system included weak and strong polyelectrolytes (PAH & DS) and a novel route was employed to fabricate optically addressable capsules that could be laser activated for delivery of drugs. This approach involved a combination of LbL assembly and polyol reduction method wherein PEG was used to reduce AgNO3 to Ag nanoparticles (NPs). The capsules were prepared via LbL assembly of PAH and DS on silica template followed by synthesis of silver NPs in the layers and subsequent dissolution of the silica core. The sulfonate groups of DS present in the polyelectrolyte film act as binding sites for the adsorption of silver ions which are then reduced to silver NPs in the presence of PEG. The size of the silver NPs formed was influenced by the AgNO3 concentration used. At lower concentration, smaller particles of uniform distribution were observed which turned into larger particles of random distribution when the concentration of AgNO3 is increased. Silver NPs embedded capsules ruptured when exposed to laser and was significantly influenced by silver NPs size, their distribution, laser intensity and time of exposure. The synthesis of silver NPs increased the permeability of the capsules to higher molecular weight substances like dextran caused by the defects, discontinuities and pores created on the polymeric network due to the newly formed silver NPs. Encapsulation of FITC-dextran was performed using thermal encapsulation method by exploiting temperature induced shrinking of the capsules at elevated temperatures. During heat treatment the porous morphology transformed into smooth pore free structure which prevented the movement of dextran into the bulk and hence enrichment inside the capsules. The loaded dextran was readily released when exposed to laser and the release could be controlled from linear to burst release in order to meet practical requirements in biomedical applications

Impact of alcohol consumption on the risk of developing Depression. A Comparative study in young and middle aged adult.

Introduction:Alcohol use disorder (AUD) is a prevalent mental health disorder that affects millions of individuals worldwide. Alcohol is a substance that can lead to several negative physical and mental health outcomes, like depression. This study aims to fill this gap by investigating the prevalence of these mental health issues among young adults and middle-aged adults who use alcohol.Objectives: This study evaluates alcohol consumption levels and mental health indicators in young and middle-aged adults, considering socioeconomic factors.Methods: This cross-sectional study in Erode Tertiary Care Hospitals examines alcohol consumption\u27s correlation with mental health in 252 young and middle-aged adults (18-59 years). Utilizing ROSOFTWARE, a 5% margin of error and 95% confidence interval determined the sample size. Inclusion criteria involved individuals with depression, and a history of alcohol use, while severe mental health disorders and Comorbidities were excluded. Data collection employed standardized tools like the Hamilton Depression, alongside a socio-demographic and alcohol consumption questionnaire. Spanning six months, the study aims to offer insights into alcohol\u27s impact on mental health in this demographic.Result and Discussion: In our study young and middle-aged adults (18-59 years) were compered for determine the mental health effect of alcohol consumption by Hamilton scale. Among 128 young adults and 124 middle aged adult, indicated a positive relationship between the alcohol and mental health. Interestingly, both age group had mental health problem but the young adults were more prone then middle aged adult because of brain development and structural changes.Conclusion: This study compares the impact of alcohol consumption on Depression in young and middle-aged adults. It highlights higher risks of Depression in young adults. These findings emphasize age-related differences in alcohol\u27s impact on mental health and offering insights for tailored prevention and intervention strategies to address associated burdens in both age groups

Computational modelling of meiotic entry and commitment

In response to developmental and environmental conditions, cells exit the mitotic cell cycle and enter the meiosis program to generate haploid gametes from diploid germ cells. Once cells decide to enter the meiosis program they become irreversibly committed to the completion of meiosis irrespective of the presence of cue signals. How meiotic entry and commitment occur due to the dynamics of the regulatory network is not well understood. Therefore, we constructed a mathematical model of the regulatory network that controls the transition from mitosis to meiosis in Schizosaccharomyces pombe. Upon nitrogen starvation, yeast cells exit mitosis and undergo conjugation and meiotic entry. The model includes the regulation of Mei2, an RNA binding protein required for conjugation and meiotic entry, by multiple feedback loops involving Pat1, a kinase that keeps cells in mitosis, and Ste11, a transcription activator required for the sexual differentiation. The model accounts for various experimental observations and demonstrates that the activation of Mei2 is bistable, which ensures the irreversible commitment to meiosis. Further, we show by integrating the meiosis-specific regulation with a cell cycle model, the dynamics of cell cycle exit, G1 arrest and entry into meiosis under nitrogen starvation. © 2017 The Author(s)

Polyelectrolyte/silver nanocomposite multilayer films as multifunctional thin film platforms for remote activated protein and drug delivery

We demonstrate a nanoparticle loading protocol to develop a transparent, multifunctional polyelectrolyte multilayer film for externally activated drug and protein delivery. The composite film was designed by alternate adsorption of poly(allylamine hydrochloride) (PAH) and dextran sulfate (DS) on a glass substrate followed by nanoparticle synthesis through a polyol reduction method. The films showed a uniform distribution of spherical silver nanoparticles with an average diameter of 50 +/- 20 nm, which increased to 80 +/- 20 nm when the AgNO3 concentration was increased from 25 to 50 mM. The porous and supramolecular structure of the polyelectrolyte multilayer film was used to immobilize ciprofloxacin hydrochloride (CH) and bovine serum albumin (BSA) within the polymeric network of the film. When exposed to external triggers such as ultrasonication and laser light the loaded films were ruptured and released the loaded BSA and CH. The release of CH is faster than that of BSA due to a higher diffusion rate. Circular dichroism measurements confirmed that there was no significant change in the conformation of released BSA in comparison with native BSA. The fabricated films showed significant antibacterial activity against the bacterial pathogen Staphylococcus aureus. Applications envisioned for such drug-loaded films include drug and vaccine delivery through the transdermal route, antimicrobial or anti-inflammatory coatings on implants and drug-releasing coatings for stents. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

A facile route to synthesize silver nanoparticles in polyelectrolyte capsules

We are reporting a novel green approach to incorporate silver nanoparticles (NPs) selectively in the polyelectrolyte capsule shell for remote opening of polyelectrolyte capsules. This approach involves in situ reduction of silver nitrate to silver NPs using PEG as a reducing agent (polyol reduction method). These nanostructured capsules were prepared via layer by layer (LbL) assembly of poly(allylamine hydrochloride) (PAH) and dextran sulfate (DS) on silica template followed by the synthesis of silver NPs and subsequently the dissolution of the silica core. The size of silver nanoparticles synthesized was 60 +/- 20 nm which increased to 100 +/- 20 nm when the concentration of AgNO3 increased from 25 mM to 50 mM. The incorporated silver NPs induced rupture and deformation of the capsules under laser irradiation. This method has advantages over other conventional methods involving chemical agents that are associated with cytotoxicity in biological applications such as drug delivery and catalysis. (C) 2011 Elsevier B.V. All rights reserved