Biomedical subjects

Anil Menon

Publications and source records attributed to Anil Menon.

6 recordsLinked to original sources

PubMed2004

Predicting polymorphic transformation curves using a logistic equation.

The commonly used solid-state reaction models (for example-Prout-Tompkins, Avrami-Erofe'ev) describe the polymorphic transformation data only over a certain range, alpha from 10% to 90%. Predictions based on a fit to a fraction of the data are inadequate because we ignore the early induction phase of the reaction, which is important for predictive purposes. A four-parameter logistic equation describes the data over the entire curve for polymorphic transformation at high temperatures. We use the parameters of the logistic equation to predict the transformation curves. The predicted curves agree with the experimental data.

Algorithms↗

PubMed2003

Case studies in blend sampling using a front-loading thief.

In-process testing is employed in pharmaceutical systems for monitoring and detecting process failures. Blend sampling is a useful in-process test. The present article outlines case studies in which sampling thieves with front-loading and side-vented mechanisms were compared. Blend uniformity analysis (BUA) using a front-loading sampling thief helped confirm or discover blend homogeneity issues and guide the product development process to rational decision points by providing quick responses to actual or impending failure with a low probability of falsely declaring a failure that is not present.

Pharmaceutical Preparations↗

PubMed2003

Time-mortality relationships for Tribolium castaneum (Coleoptera: Tenebrionidae) life stages exposed to elevated temperatures.

The use of elevated temperatures (> or = 40-60 degrees C) or heat treatments for managing insects in food-processing facilities is a viable alternative to space fumigation with methyl bromide. Quantitative data are lacking on the responses of life stages of the red flour beetle, Tribolium castaneum (Herbst), an important pest of food-processing facilities worldwide, to elevated temperatures used during heat treatments. We determined time-mortality relationships for eggs, young (neonate) larvae, old larvae, pupae, and adults of T. castaneum, exposed to constant temperatures of 42, 46, 50, 54, 58, and 60 degrees C. Generally, mortality of each stage increased with an increase in temperature and exposure time. Young larvae were the most heat-tolerant stage, especially at temperatures > or = 50 degrees C. Exposure for a minimum of 7.2 h at > or = 50 degrees C was required to kill 99% of young larvae, whereas the other stages required < or = 1.8 h. Heat treatments that control young larvae should control all other stages of T. castaneum, and young larvae should be used as test insects to evaluate efficacy against T. castaneum during an actual facility heat treatment. These results provide the basis for successful use of elevated temperatures for management of T. castaneum life stages associated with food-processing facilities.

Animals↗

PubMed2002

Sequential experimentation in product development. I.

Investigations proceed as an iterative and recursive learning process, involving a sequence of experiments. Evaluating the results from a prior set of experiments allows the investigator to design and predict the next experimental cycle better. The investigator looks at what has gone before with a view to improve and extend the inquiry. This communication reiterates the value of sequential experimentation in product development. A fluid-bed granulation study is used to illustrate the sequential approach. Acceptable solutions were achieved using technical knowledge, a sequence of factorial designs, and graphical data analysis.

Pilot Projects↗

PubMed2002

Spring: a general framework for collaborative, real-time surgical simulation.

We describe the implementation details of a real-time surgical simulation system with soft-tissue modeling and multi-user, multi-instrument, networked haptics. The simulator is cross-platform and runs on various Unix and Windows platforms. It is written in C++ with OpenGL for graphics; GLUT, GLUI, and MUI for user interface; and supports parallel processing. It allows for the relatively easy introduction of patient-specific anatomy and supports many common file formats. It performs soft-tissue modeling, some limited rigid-body dynamics, and suture modeling. The simulator interfaces to many different interaction devices and provides for multi-user, multi-instrument collaboration over the Internet. Many virtual tools have been created and their interactions with tissue have been implemented. In addition, a number of extra features, such as voice input/output, real-time texture-mapped video input, stereo and head-mounted display support, and replicated display facilities are presented.

Computer Communication Networks↗

PubMed1996

Characterization of a Class of Sigmoid Functions with Applications to Neural Networks.

We study two classes of sigmoids: the simple sigmoids, defined to be odd, asymptotically bounded, completely monotone functions in one variable, and the hyperbolic sigmoids, a proper subset of simple sigmoids and a natural generalization of the hyperbolic tangent. We obtain a complete characterization for the inverses of hyperbolic sigmoids using Euler's incomplete beta functions, and describe composition rules that illustrate how such functions may be synthesized from others. These results are applied to two problems. First we show that with respect to simple sigmoids the continuous Cohen-Grossberg-Hopfield model can be reduced to the (associated) Legendre differential equations. Second, we show that the effect of using simple sigmoids as node transfer functions in a one-hidden layer feedforward network with one summing output may be interpreted as representing the output function as a Fourier series sine transform evaluated at the hidden layer node inputs, thus extending and complementing earlier results in this area. Copyright 1996 Elsevier Science Ltd

Journal Article↗