KINETICS AND MODELING OF TANNASE PRODUCTION USING ASPERGILLUS FOETIDUS IN BATCH FERMENTATION

Objective: To produce tannase enzyme using Aspergillus foetidus with red gram husk as substrate in batch fermentor and investigate the suitable un structured kinetic model for the system.Methods: The present study was done via two steps. At first to study the maximum production of tannase enzyme by Aspergillus foetidus (MTCC 3557) using red gram husk as a substrate in a modular ferment or followed by to develop the kinetic model of tannase production.Results: The maximum tannase activity and biomass concentration were found to be 157.26 U/ml and 7.12 g/l respectively at the end of 96 hours of fermentation. The biomass yield coefficient (YX/S) and the product yield coefficient (YP/S) were found to be 0.23 g of biomass/g of substrate and 21.2 U/g of substrate respectively. Logistic model, Luedeking-Piret model and substrate utilization kinetic model were found to represent closely the experimental data of growth kinetics, product formation kinetics and substrate utilization kinetics respectively.Conclusion: Tannase enzyme production was studied using A. foetidus with redgram husk as substrate by modular fermenter and suitable models were predicted. The kinetic parameters were also estimated by fitting the data to the model using the Lineweaver-Burk method.Â

Differences In Perceptions And Fast Food Eating Behaviours Between Indians Living In High- And Low-Income Neighbourhoods Of Chandigarh, India

Increased density of fast food restaurants is associated with increased prevalence of obesity in developed countries. However, less is known about this relationship in developing countries undergoing rapid urbanization and how differences in neighbourhood income affect the patronage of fast food outlets. The purpose of the study is to explore the differences in fast food preferences, perceptions, and patronage between Indians living in high- and low-income neighbourhoods.METHODS:This cross-sectional study recruited 204 men and women (35 to 65 years in age) from high- and low-income neighbourhoods who completed a questionnaire on fast food consumption. The questionnaire asked participants to define fast food and to provide reasons for and frequency of visits to fast food restaurants. The differences were analyzed using Chi square and t-tests for categorical and continuous variables, respectively.RESULTS:Participants from a high-income neighbourhood were more likely to perceive Western -style fast food as fast food, while people from the low-income neighbourhood were more likely to identify food sold by street vendors as fast food (p <0.001). Furthermore, compared to participants from the high-income neighbourhood, people from the low-income neighbourhood were more likely to report buying food from street vendors while less likely to dine out at both fast food and non-fast food restaurants (p<0.001). Although the high-income neighbourhood group was more likely to report enjoying eating at fast food restaurants than their low-income neighbourhood counterparts, there were no significant differences in the reasons for visiting fast food restaurants (convenience, price, social enjoyment, and quality of meals) between the two groups. Both groups preferred home cooked over restaurant meals, and they recognized that home cooked food was healthier.CONCLUSIONS:Overall, consumption of fast food was low. People from a high-income neighbourhood dined out more frequently and were more likely to perceive Western-style food as fast food compared to their counterparts from the low-income neighbourhood

Safety and feasibility of single use cholecystoscopy for guiding laser or mechanical cholelithotripsy, and mechanical cholelithotomy

PURPOSEPatients with acute calculus cholecystitis and contraindications to cholecystectomy receive cholecystostomy drainage catheters, many of which remain in place until end of life. This study aims to assess safety, feasibility, and early clinical outcomes of percutaneous cholecystoscopy using the LithoVue endoscope, laser/mechanical cholelithotripsy, and mechanical cholelithotomy for management of symptomatic cholelithiasis.METHODSThis was a single-institute retrospective analysis of 17 patients with acute calculus cholecystitis who had contraindications to cholecystectomy, underwent cholecystostomy catheter placement between 2015 and 2017, and stone removal between 2017 and 2018. The LithoVue 7.7- 9.5 F endoscope was used in combination with laser/mechanical cholelithotripsy, mechanical retrograde, and balloon-assisted anterograde cholelithotomy to remove gallstones and common bile duct stones. Surgical contraindications ranged from cardiopulmonary disease to morbid obesity to neoplastic processes. Timing and number of interventions, as well as technical and clinical successes, were assessed.RESULTSThe median time interval from cholecystostomy catheter placement to cholelithotripsy was 58 days, after an average of 2 tube exchange procedures. Technical and clinical success were achieved in all patients (stone-free gallbladder and cholecystostomy tube removal). On average, three sessions of cholecystoscopy and laser and mechanical cholelithotripsy were required for complete gallstone extraction. The mean interval time between the first cholelithotripsy session and removal of cholecystostomy was 71.8±60.8 days. There were neither major nor minor procedure-related complications.CONCLUSIONPercutaneous cholecystoscopy using the LithoVue endoscope, in combination with laser/ mechanical cholelithotripsy and mechanical cholelithotomy, is feasible, safe, well-tolerated, and was able to remove the cholecystostomy tube in the patients with contraindication to cholecystectomy

American option pricing under stochastic volatility : a simulation-based approach

We consider the problem of pricing American options when the volatility of the underlying asset price is stochastic. No specific stochastic volatility model is assumed for the stochastic process. We propose a simulation-based approach to pricing such options. Iteratively, the method determines the optimal exercise boundary and the associated price function for a general stochastic volatility model. Given an initial guess of the optimal exercise boundary, the Retrospective Approximation (RA) technique is used to calculate the associated value function. Using this function, the exercise boundary is improved and the process repeated till convergence. This method is a simulation based variant of the exercise-policy improvement scheme developed in Chockalingam and Muthuraman (2007). An illustration of the method is provided when using the Heston (1993) model to represent the dynamics of the volatility, together with comparisons against existing methods to validate our numerical results

Strategic risk, banks, and Basel III: estimating economic capital requirements

Purpose: Basel III regulations require banks to protect themselves against strategic risk. This paper aims to provide a comprehensive and measurable definition of this risk and proposes a framework to estimate economic capital requirements. Design/methodology/approach: The paper studies the literature and solicits expert opinion in formulating a comprehensive and measurable definition of strategic risk. The paper postulates that the economic capital for a bank’s strategic risk should be estimated using the cost of equity as the profitability threshold, rather than zero and develops a simulation-based framework to estimate economic capital. Findings: The framework closely matches the actual economic capital outlay for strategic risk from our case study of ABN AMRO. It is shown that a bank’s strategic growth plans can fall into one of two scenarios based on risk-return characteristics. In one scenario, the required economic capital outlay will increase, and decrease in the other. Practical implications: This framework is generalizable and makes use of widely accepted and used practices in banks, making it readily implementable in practice. It does not introduce errors resulting from model selection, parameterizations or complex calculations. Social implications: Society would be worse off in the absence of banking and lending services. Banks need to take risks to grow and stay competitive. The framework facilitates better strategic risk management, protecting banks from collapse and reducing the need for taxpayer-funded bailouts. Originality/value: The paper provides a measurable and practitioner-verified definition of strategic risk and proposes a simple framework to estimate economic capital requirements, a crucial topic, given the threats and increased levels of strategic risk facing banks

Buyer-backed purchase-order financing for SME supplier with uncertain yield

Access to adequate working capital is often a challenge for SMEs, especially if SME faces the risk of an uncertain yield. We identify conditions under which a strong buyer should either offer “backing”or guar- antee for the purchase-order finance for a cash-constrained, risky SME supplier, or end the relationship. By offering a backing, buyer shares the default risk faced by the bank, in order to keep the SME supplier in business. To identify the possible benefits of this scheme, we compare the buyer’s operational and financial decisions under three financing mechanisms: buyer-backed purchase order financing, purchase order financing with no backing and purchase order financing with a fixed buyer-backing. The non-linear optimization problem is solved using KKT optimality conditions and sufficiency is established through invexity. We perform numerical experiments for all the models for different levels of yield risks of the supplier. We are able to separate conditions to suggest when (1) no backing is required; (2) when backing should be offered to sustain the supplier, and (3) when an alternative supplier should be located. We find that backing has the following benefits: buyer can use backing as a substitute to higher purchase price; it helps the supplier to stay operative till a higher shock level; shared risk of default leads the bank to offer financing at a lower rate; finally resulting in consistently higher buyer profits despite the added risk. The separation condition as described above can also be used by managers to compare two suppliers