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Biomedical subjects

K Murali

Publications and source records attributed to K Murali.

11 recordsLinked to original sources
PubMed2005

Synthesis and antidepressant activity of some 1,3,5-triphenyl-2-pyrazolines and 3-(2''-hydroxy naphthalen-1''-yl)-1,5-diphenyl-2-pyrazolines.

Five new 1,3,5-triphenyl-2-pyrazolines were synthesised by reacting 1,3-diphenyl-2-propene-1-one with phenyl hydrazine hydrochloride and another five new 3-(2''-hydroxy naphthalen-1''-yl)-1,5-diphenyl-2-pyrazolines were synthesised by reacting 1-(2'-hydroxynaphthyl)-3-phenyl-2-propene-1-one with phenyl hydrazine hydrochloride. The structures of the compounds were proved by means of their IR, (1)H NMR spectroscopic data, and microanalyses. The antidepressant activity of these compounds was evaluated by the 'Porsolt behavioural despair test' on Swiss-Webster mice.1-Phenyl-3-(2''-hydroxyphenyl)-5-(4'-dimethylaminophenyl)-2-pyrazoline, 5-(4'-dimethylaminophenyl)-1,3-diphenyl-2-pyrazoline, 1-phenyl-3-(2''-hydroxynaphthalen-1''-yl)-5-(3',4',5'-trimethoxyphenyl)-2-pyrazoline, 1-phenyl-3-(4''-methylphenyl)-5-(4'-dimethylaminophenyl)-2-pyrazoline and 1-phenyl-3-(4''-bromophenyl)-5-(4'-dimethyl amino phenyl)-2-pyrazoline reduced immobility times 25.63-59.25% at 100mg/kg dose level. In addition, it was found that the compounds possessing electron-releasing groups such as dimethyl amino, methoxy and hydroxyl substituents, on both the aromatic rings at positions 3 and 5 of pyrazolines, considerably enhanced the antidepressant activity when compared to the pyrazolines having no substituents on the phenyl rings.

Animals↗
PubMed2005

Commentary from the front lines: American physician assistants working in a United Kingdom emergency department.

Physician assistants (PAs) have been an integral part of the emergency medicine team in the USA for the past 30 years. This review outlines the reasons why PAs can play a vital role in UK National Health Service (NHS). The experience of American PAs working in one NHS trust are discussed, highlighting the cultural differences in the environment of the emergency departments in the two countries that will influence the scope of practice of PAs in the UK.

Emergency Medical Technicians↗
PubMed2003

Experimental realization of chaos control by thresholding.

We report the experimental verification of thresholding as a versatile tool for efficient and flexible chaos control. The strategy here simply involves monitoring a single state variable and resetting it when it exceeds a threshold. We demonstrate the success of the technique in rapidly controlling different chaotic electrical circuits, including a hyperchaotic circuit, onto stable fixed points and limit cycles of different periods, by thresholding just one variable. The simplicity of this controller entailing no run-time computation, and the ease and rapidity of switching between different targets it offers, suggests a potent tool for chaos based applications.

Journal Article↗
PubMed2003

Realization of the fundamental NOR gate using a chaotic circuit.

We report the experimental verification of a simple threshold controller, which clips the chaos to periods of widely ranging orders, in a chaotic circuit. Then we use this to implement the fundamental NOR gate thus obtaining a proof of principle experiment demonstrating the universal computing capability of chaotic systems.

Journal Article↗
PubMed2003

A novel method of demonstrating rectal prolapse.

BACKGROUND: Full thickness rectal prolapse may be difficult to view in the outpatient setting. We present a novel method to demonstrate it using equipment commonly found in the Urology clinic.

Equipment Design↗
PubMed2002

Ergodic chaos-based communication schemes.

Recent studies have shown the applicability of synchronized chaotic systems to the area of communications in different ways. At the same time synchronization based signal recovery and estimation of parameters severely suffer due to the presence of channel noise. By exploiting the ergodic properties of chaotic signals effectively, a simple technique called the mean-value method is introduced. This method is shown to be capable of estimating chaos system parameters from the transmitted chaotic signal efficiently for a low signal-to-noise ratio. A suitable demodulator has been designed for ergodic chaotic parameter modulation scheme for digital signal communication. Further, the mean-value technique incorporates a noncoherent receiver to recover analog information signal from the chaos masked signal efficiently. It is found that the proposed chaotic masking scheme is robust even in the presence of strong noise. In addition, this scheme has the potential advantage of a very simple hardware realization, which promises enhanced signal recovery performances.

Journal Article↗
PubMed2002

Systematic review of the efficacy and safety of colorectal stents.

BACKGROUND: Colorectal stents are being used for palliation and as a 'bridge to surgery' in obstructing colorectal cancers. METHODS: A systematic review of the published data on stenting for the treatment of colorectal obstruction was carried out by searching Medline and other online databases for the period from January 1990 to December 2000. A total of 58 publications (case series, single case reports and reviews) was found, of which 29 case series were included in the analysis. Technical and clinical success, complications and reobstruction, both in palliation and as a 'bridge to surgery', were assessed. Both descriptive statistics and pooled analyses were carried out. RESULTS: Pooled results showed that stent insertion was attempted in 598 instances. Technical success was achieved in 551 (92 per cent) and clinical success in 525 (88 per cent). Palliation was achieved in 302 (90 per cent) of 336 cases, while 223 (85 per cent) of 262 insertions succeeded as a 'bridge to surgery' (95 per cent had a one-stage surgical procedure). There were three deaths (1 per cent). Perforation occurred 22 times (4 per cent). Stent migration was reported in 54 (10 per cent) of 551 technically successful cases. The rate of stent reobstruction was 52 (10 per cent) of 525, mainly in the palliative group. CONCLUSION: Evidence suggests that colorectal stents offer good palliation, and are safe and effective as a 'bridge to surgery'. Stent usage can avoid the need for a stoma, and is associated with low rates of mortality and morbidity. Dilatation of malignant strictures at the time of stent placement appears to be dangerous and should be avoided.

Adult↗
PubMed2001

Simple electronic circuit model for doubly stochastic resonance.

We have recently reported the phenomenon of doubly stochastic resonance [Phys. Rev. Lett. 85, 227 (2000)], a synthesis of noise-induced transition and stochastic resonance. The essential feature of this phenomenon is that multiplicative noise induces a bimodality and additive noise causes stochastic resonance behavior in the induced structure. In the present paper we outline possible applications of this effect and design a simple lattice of electronic circuits for the experimental realization of doubly stochastic resonance.

Journal Article↗
PubMed2000

Digital signal transmission with cascaded heterogeneous chaotic systems.

A new chaos based secure communication scheme is proposed to transmit digital signals by combining the concepts of chaotic-switching and chaotic-modulation approaches. In this scheme two heterogeneous chaotic circuits are used both at the transmitter and receiver modules. First a binary message signal is scrambled by two chaotic attractors produced by a set of chaotic systems (No. 1) of the drive module. The so produced small amplitude scrambled chaotic signal is further directly injected or modulated by different chaotic system (No. 2) within the drive module. Then the chaotic signal generated by this second chaotic system No. 2 is transmitted to the response module through the channel. An appropriate feedback loop is constructed in the response module to achieve synchronization among the variables of the drive and response modules and the binary information signal is recovered by using the synchronization error followed by low-pass filtering and thresholding. Simulation results are reported in which the quality of the recovered signal is higher and the encoding of the information signal is potentially secure. The effect of perturbing factors like channel noise and nonidentity of parameters are also considered.

Journal Article↗