Study of aberrations of stepper lenses in-situ using phase shifting point diffraction interferometry

Stepper lenses are tested by the lens manufacturer using various interferometric methods like phase measurement interferometry (PMI), before they are assembled onto the stepper or scanner. Once the system is set up, there are a few methods to study the lens aberrations in-situ using interferometry. The methods currently used are direct ones like direct aerial image measurement (DAIM) or indirect ones in which images of lines and spaces are formed in the photoresist and the aberrations inferred from scanning electron microscope (SEM) images of these. We propose using phase shifting point diffraction interferometry (PSPDI) for the purpose of measuring aberrations in-situ. The method has the advantages of being simple, and of having relaxed coherence length requirements and applicability over a wide wavelength range. We present results from a prototype experiment done on a 436 nm optic on an optical bench using a 442 nm He-Cd laser as source

Niacin production test in mycobacteria: Replacement of benzidine - cyanogen bromide reagent by o-tolidne - cyanogen bromide

The identification of M. tuberculosis depends primarily on the niacin production test. Runyon and others (1959) described a method based on the observations of Konno (1956) using aniline as the reagent. However, the aniline reagent gives a yellow colour which can cause difficulty in the interpretation of the results, particularly in the case of the chromogenic mycobacteria. Hence several workers prefer the test employing benzidine (Medveczky, 1960) or o-tolidine (Guttierrez-Vazquez, 1960), since the pink colour produced in these tests is easier to read. The standard method for niacin production test at this Centre has been the one using benzidine. However, satisfactory supplies of benzidine are no longer available, as the manufacture of this compound’ has recently been stopped. Hence it was decided to investigate the test using o-tolidine. Though other workers (Tarshis, 1960, 1961; Gangadharam and Droubi, 1971) have compared the benzidine and o-tolidine methods on small numbers of cultures, no large scale investigation of these two methods has been reported. Therefore a direct controlled comparison of these two methods was undertaken, the results of which are reported here

Identification of critical residues in loop E in the 5-HT(3AS)R binding site

BACKGROUND: The serotonin type 3 receptor (5-HT(3)R) is a member of a superfamily of ligand gated ion channels. All members of this family share a large degree of sequence homology and presumably significant structural similarity. A large number of studies have explored the structure-function relationships of members of this family, particularly the nicotinic and GABA receptors. This information can be utilized to gain additional insights into specific structural and functional features of other receptors in this family. RESULTS: Thirteen amino acids in the mouse 5-HT(3AS)R that correspond to the putative E binding loop of the nicotinic α7 receptor were chosen for mutagenesis. Due to the presence of a highly conserved glycine in this region, it has been suggested that this binding loop is comprised of a hairpin turn and may form a portion of the ligand-binding site in this ion channel family. Mutation of the conserved glycine (G147) to alanine eliminated binding of the 5-HT(3)R antagonist [(3)H]granisetron. Three tyrosine residues (Y140, Y142 and Y152) also significantly altered the binding of 5-HT(3)R ligands. Mutations in neighboring residues had little or no effect on binding of these ligands to the 5-HT(3AS)R. CONCLUSION: Our data supports a role for the putative E-loop region of the 5-HT(3)R in the binding of 5-HT, mCPBG, d-tc and lerisetron. 5-HT and mCPBG interact with Y142, d-tc with Y140 and lerisetron with both Y142 and Y152. Our data also provides support for the hypothesis that this region of the receptor is present in a loop structure

Drug resistance in tuberculosis and issues related to multidrug resistance in planning for TB control in India

There is no clear evidence of an increase in the prevalence of initial drug resistance in India over the years. However, relatively high prevalence of acquired resistance has been reported. The level of initial drug resistance is said to be an epidemiological marker to assess the success of the National TB Programme. This also influences the design of the regimens to be employed as well as policy decisions

Drug resistance in tuberculosis in India

The current global concern in the treatment of tuberculosis (TB) is the emergence of resistance to the two most potent drugs viz., isoniazid and rifampicin. The level of initial drug resistance is an epidemiological indicator to assess the success of the TB control programme. Though drug resistance in TB has frequently been reported from India, most of the available information is localized, sketchy or incomplete. A review of the few authentic reports indicates that there is no clear evidence of an increase in the prevalence of initial resistance over the years. However, a much higher prevalence of acquired resistance has been reported from several regions, though based on smaller numbers of patients. A strong TB control programme and continuous surveillance studies employing standardized methodology and rigorous quality control measures will serve as useful parameters in the evaluation of current treatment policies as well as the management of multidrug resistant (MDR) TB cases

Anxiolytic activity of ethanolic and aqueous extract of Ficus carica Linn fruits in swiss albino mice

Background: Benzodiazepams are mainly used to treat anxiety but these drugs produce serious adverse effects, hence herbal drugs are preferred. The present study was undertaken to evaluate the anti-anxiety activity of ethanolic and aqueous extract of Ficus carica (FC) Linn fruits in swiss albino mice.Methods: Male swiss albino rats weighing 25-30gms were divided into six groups and six animals in each group. Diazepam (1.0 mg/kg), AEFC (200 and 400 mg/kg) and EEFC (200 and 400 mg/kg) were suspended in 1% gum acacia and administered orally. The EEFC and AEFC (both extracts at 200 and 400mg/kg/p.o) and vehicle were administered for 7 days once daily p.o. and the last dose was given on the 7lh day, 60 min prior to exposure to the experimental paradigms viz., Elevated plus maze, T- maze model and Hole -board model.Results: Both the extracts of FC significantly increased the number of entries into, time spent and rears in the open arms. Also, it increased the percentile ratio of open arm to total arm entries in elevated plus maze. In T- maze, the both the extracts FC showed a significant increase in baseline latency and decrease in escape and avoidance. In the hole-board model a significant increase in the exploratory behavior like head-dipping and line crossing, rearing was observed after treatment with EEFC and AEFC. FC also decreases the nor-adrenaline levels and increase in serotonin and dopamine levels in the brain. These behavioural changes were significantly higher than that produced by the standard anxiolytic drug diazepam.Conclusions: It was concluded that ethanolic and aqueous extracts of Ficus carica fruits having antianxiety activity