Optimisation of lipase-catalysed interesterification reaction for modulating rheological and heat transfer properties of frying oil

The present work reports the optimisation of enzyme interesterification reaction of rice bran oil (RBO) and refined, bleached, deodorized, palm olein (RBDPO) blend using immobilized 1,3-specific lipase, to improve the kinematic viscosity and heat transfer coefficient of oil, important for characterising heat transfer during the frying process. Four variables, namely RBO (20–80%) in RBO–RBDPO blend, reaction temperature (25–65 °C), enzyme concentration (1–13%, w/w) and reaction time (1–13 h) were selected and optimised using response surface methodology (RSM) coupled with central composite rotatable design (CCRD). The optimisation results predicted that optimum reaction conditions for preparing enzyme interesterified oil, having minimum kinematic viscosity (2.63 × 10⁻⁶ m² s⁻¹) and maximum heat transfer coefficient (262.0 Wm⁻² °C⁻¹) were at 62% RBO, temperature 65 °C, enzyme concentration 10% (w/w) and time 6.4 h. The predicted values were validated experimentally and corroborated with DSC melting profile and triacylglycerol molecular species data. This investigation could help snack food industries to develop suitable oils for frying operations.     

Herpes simplex encephalitis: treatment with surgical decompression and cytosine arabinoside

Herpes simplex encephalitis in a 21-year-old man presented as a flu-like illness, followed by inappropriate behaviour, drowsiness and focal neurologic signs. Investigations indicated a lesion in the right temporal lobe. The diagnosis was confirmed by isolation of the virus from a cerebral biopsy. Pronounced clinical improvement was noted when cytosine arabinoside therapy was started in the postoperative period. This report supports the observation by some authors that cytosine arabinoside may be of value in the treatment of herpes simplex encephalitis.     

The immunosuppressive effect of concanavalin A in monkeys

These studies were performed to evaluate the immunosuppressive effect of concanavalin A (ConA) in monkeys. Bonnet monkeys (Macaca radiata) weighing between 2.5-3.5 kg were used. Following the exchange of full thickness skin allografts in randomly selected animals, gross and histopathological studies of the rejection reaction were performed. Gross observations showed the allograft reaction in control animals to be a well defined phenomenon occurring at 9.0 +/- 0.7 days. In contrast the rejection process in animals that received i.v. ConA was a poorly defined prolonged process occurring at 14.8 +/- 3.9 days (single 75-mg dose of ConA), and 19.0 +/- 2.2 days (75 mg 1 day before and 25 mg 3 days after grafting). In monkeys that received the double dose schedule of ConA, histopathological studies showed distinct retardation of the rejection reaction with reduced lymphocytic infiltration of the graft-host junction. Control grafts showed almost complete rejection in 7-9 days while allografts on ConA-treated animals showed corresponding degrees of destruction only by the 15th day. These studies indicate that ConA does have an immunosuppressive effect in vivo in monkeys. The local and systemic toxic effects of ConA encountered in these animals have been reported and its haematological effects in vivo briefly described.     

Permanent cardiac pacemakers in children: technical considerations

Placement of permanent cardiac pacemakers in children presents technical problems that are not encountered in the adult. Problems unique to pacemaker implantation in children are related to the patient's size, the relative bulkiness of pulse generators, the lack of subcutaneous tissue, and the child's growth and long life expectancy. Based on our experience with implantation of 27 permanent cardiac pacemakers in 13 children, we have found that the use of small pulse generators, placement of epicardial leads, insertion of properitoneal pulse generators, and use of recharabeable pacemakers are satisfactory methods in children.     

Design tool and its experimental validation for SOA-based photonic signal processing

This paper reports a unified, accurate and fast simulation tool, able to describe photonic SOA-based digital processing schemes. The model exploits cross gain modulation in SOAs in time resolved analysis in which each amplifier can be thought of as a point amplifier. Simulation and experimental comparisons of the steady state and dynamic amplified spontaneous emission noise behaviour of SOA are carried out. Details of multistage modelling useful for long nonlinear SOA has been described. Implementation of schemes such as combinatorial logic functions may require many cascading SOAs and contribution of ASE noise from each amplifier also been taken into account. A procedure of the extraction of parameters from the commercial SOA utilised in the experiment is laid down. Various sources of degradation have been identified and the method for evaluation of bit error rate for complex SOA based combinatorial network has been outlined. The tool is validated through the implementation of a photonic bit comparator. Important design guidelines are extracted by the proposed tool.     

Selftuning control of some pilot plant processes

This paper reviews the results of some experimental tests carried out to evaluate the performance of selftuning (ST) controllers for temperature control of a continuous stirred tank heater, composition control of a binary distillation column and pH control of an acidic effluent. All the pilot plant units have been controlled using a single variant selftuning control, and a newly developed multivariant ST controller was used for simultaneous control of the terminal compositions of the distillation column. The control performance of the units operating under ST control is compared to that obtained using very well tuned proportional plus integral (PI) or proportional plus integral plus derivative (PID) conventional controllers. Control of pH is shown using a technique of electrochemical neutralisation coupled with a single variant ST controller. The control algorithms have been programmed on a number of microprocessor- and minicomputer-based systems. Z80 for stirred tank heater control, LS1-11 for pH control and HP1000 distributed computer system for distillation control.