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We have prepared the composites of a room temperature nematic liquid crystal mixture by dispersing small fractions of Multi-Walled Carbon Nanotubes into its matrix. The electro-optical and dielectr...

Poly-crystalline Si film is an important material for its applications in microelectronics and solar cells. In order to realize poly-crystalline Si for practical application with high performance, it needs to be fabricated at room temperature. In this paper, we present a novel technique to develop poly-crystalline Si thin films at room temperature using 500 keV Xe+ ion irradiation. Here, the Al-induced crystallization process is employed to reduce the crystallization temperature. For that, c-Al (50 nm)/a-Si (150 nm) bilayer thin films have been used for ion irradiation experiments. Structural studies show that crystallization of Si starts at a threshold fluence of 3 × 1015 ions cm−2, and crystallinity is found to increase with increasing ion fluence. The results are explained in terms of displacement spike and thermal spike due to the interaction of energetic ions with target atoms. The transport of ions in matter Monte Carlo computer simulation code has been used to estimate the number of displacements due to ion irradiation. Generation of a sufficient amount of free Si atoms at threshold fluence and diffusion of these free Si atoms along the Al grain boundary starts the nucleation process.

We have prepared the composite of a room temperature nematic liquid crystalline material namely 4-(trans-4′-n-hexylcyclohexyl) isothiocyanatobenzoate (6CHBT) and silver nanoparticles (AgNPs...

We have prepared the composites of a room temperature Nematic Liquid Crystals and Single-Walled Carbon Nanotubes. Effect of dispersion of nanotubes on various dielectric and electro-optic p...

Single-wall carbon nanotubes (SWCNTs) were dispersed in the nematic matrix of a room temperature pristine liquid crystalline material. Thermodynamic, electro-optical and dielectric parameters of nematic host dispersed with SWCNTs were investigated. The alignment and reorientation of SWCNTs with external electric field in nematic matrix were also studied. The inclusion of SWCNTs changes the physical parameters such as transition temperature, switching threshold voltage, orientational order, dielectric anisotropy, splay elastic constants and activation energy of host nematic liquid crystal. The switching threshold voltage reduces and the steepness of the transmission voltage curve improves for the composite systems. This shows that dispersion of SWCNTs enhances the orientational order of nematic liquid crystals media. Consequently overall improvements were observed for the display parameters of dispersed systems.

Thermodynamic and electro-optical characterization of a ferroelectric liquid crystalline material, namely ((S) (+) 4-(1-methylheptyloxy) phenyl 4′-octyloxybiphenyl-4-carboxylate) possessing paraelectric SmA*, ferroelectric SmC*, hexatic SmBh* and SmI* phases has been carried out. Phase identification has been done by optical and thermodynamic studies. Switching parameters viz. spontaneous polarization, switching time and rotational viscosity have been determined. The spontaneous polarization has been found to increase with decreasing temperature in SmC* phase. The switching time is found of the order of few milliseconds.

We have prepared the composites of a room temperature nematic liquid crystalline material namely 4-(trans-4′-n-hexylcyclohexyl) isothiocyanatobenzoate (6CHBT) and gold nanoparticles (GNPs). Thermodynamic, electro-optical and dielectric properties have been investigated. Effect of dispersion of GNPs on various electro-optical and display parameters of host liquid crystalline material have been studied. Physical parameters such as threshold voltage, dielectric anisotropy and splay elastic constant have altered for composite systems. Due to the dispersion of GNPs, nematic to isotropic transition temperature is significantly increased. Relaxation frequency corresponding to flip-flop motion of the 6CHBT molecules about their short axes has increased due to the presence of GNPs.

The optical properties of cadmium selenide quantum dots were investigated in the nematic liquid crystals, which were used as an anisotropic medium. The effects of anisotropic media on the optical properties of immersed quantum dots were studied through ultra-violet absorption/transmission spectroscopy. The optical band gap and refractive index of immersed quantum dots were calculated for isotropic and anisotropic medium. The influences of anisotropic medium on the optical properties of quantum dots were discussed in terms of anchoring of liquid crystals molecules on the surfaces of immersed quantum dots.

Composites were prepared by inserting Single-Walled Carbon Nanotubes (SWCNTs) in the Nematic Liquid Crystal (NLC) to fasten the reorientation dynamics of the system under the electric field. Dispersion of SWCNTs in NLC medium enhanced the orientational order and consequently the display parameters of composite systems improved. Various display parameters such as orientational order, dielectric anisotropy, threshold voltage and splay elastic constant were explored for pure and composite systems.

BACKGROUND Diagnosis of tuberculosis (TB) in children remains challenging due to the paucibacillary nature of the disease. Detection of TB using urine lipoarabinomannan (LAM) antigen was evaluated in children with presumed TB. MATERIAL and METHODS Children with presumed intrathoracic tuberculosis (ITTB) and lymph node TB (LNTB) were enrolled. Expectorated or induced sputum or gastric aspirates from ITTB patients and fine-needle cytological aspirates from LNTB patients were subjected to Ziehl-Neelsen staining, MGIT™960™ culture and Xpert® MTB/RIF testing. Urine samples were tested to detect LAM, and the sensitivity and specificity calculated. RESULTS Of 280 children with presumed ITTB and 101 with presumed LNTB, respectively 71 (25.3%) and 25 (24.7%) were categorised as 'confirmed TB', 70 (25%) and 33 (32.7%) as 'unconfirmed TB', and 139 (49.6%) and 43 (42.5%) as 'unlikely TB'. Respectively 8 (2.8%) children with ITTB and 3 (2.9%) with LNTB were positive on smear, 56 (20.0%) and 23 (22.7%) on Xpert, and 50 (17.8%) and 9 (8.9%) on culture. LAM assay sensitivity was 73.2% in confirmed ITTB cases, and 76% in confirmed LNTB cases; LAM assay specificity in children with ITTB and those with LNTB initiated on anti-tuberculosis treatment was respectively 92% and 93%. Detection of TB using the LAM assay was significantly better than detection using Xpert (P CONCLUSION Urinary LAM testing showed high specificity and sensitivity, was detected in more cases initiated on treatment than reference tests, and improved disease detection by 38.5% in ITTB patients and by 41.6% in LNTB patients. .

The effect of Iron Oxide Nanoparticles (γ-Fe2O3 NPs) on a room temperature nematic liquid crystalline material namely 4-(4′-hexylcyclohexyl) isothiocyanatobenzene (6CHBT) has been studied. The ferronematic composites have been characterized using differential scanning calorimetry, polarizing optical microscopy, dielectric spectroscopy and electro-optical measurements. It is found that the ferronematic with the low concentration of γ-Fe2O3 NPs enhanced the orientational ordering of nematic matrix due to the strong orientational coupling between magnetic dipole moments associated to nanoparticles and nematic liquid crystal director, which is the essential feature of these systems. It resulted the improvement of various parameters of liquid crystals important for the application. In the ferronematics, the nematic to isotropic transition temperature increased as compared to that of the pure material. Dielectric spectroscopy has shown an increase of dielectric anisotropy in the composite systems. Electro-optical results reveal a decrement in both the splay elastic constant and the electric threshold voltage, in line with a noteworthy improvement of the steepness of transmission- voltage curves.

Thermodynamical, optical, dielectric and electro-optical characterisation of nematic liquid crystals (LCs) and silver nanoparticle (NP) composites have been carried out. Transition temperatures of pure and composites systems have been measured. Thermodynamical studies suggest increase of clearing temperature of the composite material as compared to the pure material. Threshold voltage for switching from bright to dark state and splay elastic constant of the pure and composite materials have been determined. From frequency dependence of dielectric measurements, permittivity, loss, relaxation frequency and dielectric strength of flip-flop mechanism of LC molecules in the nematic phase have been calculated. Dielectric properties of composites have been explained in reference of Maier and Meier theory. The effects of doping of NPs on dielectric and electro-optic properties of LC-NP composites have been discussed.

Purpose: The purpose of this study was to evaluate the identification of Mycobacterium tuberculosis which is often plagued with ambiguity. It is a time consuming process requiring 4-8 weeks after culture positivity, thereby delaying therapeutic intervention. For a successful treatment and disease management, timely diagnosis is imperative. We evaluated a rapid, proteomic based technique for identification of clinical mycobacterial isolates by protein profiling using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Materials and Methods: Freshly grown mycobacterial isolates were used. Acetonitrile/trifluoroacetic acid extraction procedure was carried out, following which cinnamic acid charged plates were subjected to identification by MALDI-TOF MS. Results: A comparative analysis of 42 clinical mycobacterial isolates using the MALDI-TOF MS and conventional techniques was carried out. Among these, 97.61% were found to corroborate with the standard methods at genus level and 85.36% were accurate till the species level. One out of 42 was not in accord with the conventional assays because MALDI-TOF MS established it as Mycobacterium tuberculosis (log (score) >2.0) and conventional methods established it to be non-tuberculous Mycobacterium. Conclusions: MALDI-TOF MS was found to be an accurate, rapid, cost effective and robust system for identification of mycobacterial species. This innovative approach holds promise for early therapeutic intervention leading to better patient care.

Studies on Pneumocystis jirovecii dihydropteroate synthase (DHPS) genotypes among non-HIV immunocompromised patients from developing countries are rare. In the present prospective investigation, 24 (11.8%) cases were found to be positive for Pneumocystis jirovecii out of 203 non-HIV patients with a clinical suspicion of Pneumocystis pneumonia (PCP). Dihydropteroate synthase (DHPS) genotype 1 (Thr55+Pro57) was noted in 95.8% P. jirovecii isolates in the present study in contrast to only 4.1% of patients with DHPS genotype 4 (Thr55Ala + Pro57Ser).

ON SEMI-SYMMETRIC CONNECTION PARAMETERS IN FINSLER SUBSPACES

Land application of wastewater in the northern-tier United States during winter months has been suggested as a means to reduce cost of building storage lagoons. A study was initiated in 1996 to assess land application of potato-processing wastewater on a 120-ha field at Park Rapids, MN. One objective of this study was to evaluate the effects of soil P levels and temperature on P leaching in soil columns. In this paper, we report the P sorption, desorption, and leaching characteristics of a high-P (>200 mg kg(-1)) and a low-P (

Twenty male buffalo calves of 6-9 months of age (average body weight, 97 kg) were randomly allocated into two main groups of four (control) and sixteen (supplemented) calves. The supplemented group was further divided in to four equal sub-groups, with the two groups supplemented with a liquid preparation of urea-molasses, UML1, containing fish meal and UML2, containing formaldehyde treated deoiled mustard cake (FDMC) and the other two, with a semi-solid preparation, UMC1 with FDMC and deoiled rice bran (DORB) contributing similar level of CP as in UML2 and UMC2 with double the level of FDMC to that in UMC1. The control group was fed with DORB along with ad libitum wheat straw at 40:60 ratios. The rest of the groups were fed on the above diet supplemented with 500 g (as fed basis) of urea-molasses preparations. The experimental feeding was carried out for 24 weeks including a metabolism trial towards the end of experimental feeding. Daily feed intake and fortnightly change in live weight were also recorded during the study. Catalytic supplementation of 500 g urea-molasses induced 8-25% higher voluntary feed intake of wheat straw, resulting in 15-25% higher DM and OM intake. The digestibility of DM, OM, total carbohydrate, NDF, ADF, hemicellulose and cellulose in all the dietary groups were comparable. The CP digestibility of calves in supplemented groups were higher (p

Polydimethylsiloxane (PDMS) is a widely used silicone polymer that is introduced into wastewater treatment systems where it is removed with sludge. PDMS subsequently enters the terrestial environme...

Silicone polymers [poly(dimethylsiloxane)s, PDMS] are used in down-the-drain consumer products and enter soil through disposal of municipal sludge. We examined PDMS hydrolysis over a range of soil moistures in soils from different geographical regions. [14C]PDMS 350 cSt was added (50 mg kg-1) to a Michigan Alfisol (Londo sandy clay loam) at six water potentials. Hydrolysis (5-week incubation) was 16, 2.0, 0.14, and 0.09% wk-1 at −76, −18, −5.4, and −1.2 MPa, respectively. Hydrolysis at −0.26 and −0.05 MPa was too slow to distinguish from experimental variability. When dry Londo soil was amended with PDMS and then remoistened to −0.05 MPa, hydrolysis was 0.19% wk-1, meaning that remoistening of soil slows the reaction. Similarly, PDMS hydrolysis in remoistened soils (−0.04 to −0.1 MPa) from Ohio (Alfisol), Georgia (Ultisol), and Puerto Rico (Oxisol) was 0.41, 1.25, and 1.26% wk-1, respectively. Best-fit regression equations (R 2 > 0.99) showed a linear dependence of rate constant on water potential from −0...

Nutrient acquisition and growth of citronella Java (Cymbopogon winterianus Jowitt) was studied in a P-deficient sandy soil to determine the effects of mycorrhizal symbiosis and soil compaction. A pasteurized sandy loam soil was inoculated either with rhizosphere microorganisms excluding VAM fungi (non-mycorrhizal) or with the VAM fungus, Glomus intraradices Schenck and Smith (mycorrhizal) and supplied with 0, 50 or 100 mg P kg-1 soil. The soil was compacted to a bulk density of 1.2 and 1.4 Mg m-3 (dry soil basis).

The effect of row spacings (45, 60 and 75 cm) and various amounts of nitrogen fertilizer (0,100,200 and 300 kg N/ha) on plant growth, essential oil production and composition of Scotch spearmint was studied in the field during 1987 and 1988 in Lucknow, India. Nitrogen application increased plant height and leaf area index while decreased leaf-stem ratio and oil concentration, irrespective of row spacings. The green herbage and oil yields increased significantly up to an application of 200 kg N/ha at 45 or 60 cm row spacing as against up to 300 kg N/ha at 75 cm row spacing. The higher N application at 75 cm row spacing, however, did not increase oil yield compared to application of 200 kg N/ha at 60 cm row spacing. Row spacing influenced various response functions and optimum N rate. At optimum N, response per kg N, net return per kg N and benefit-cost ratio were highest at 60 cm row spacing. Oil concentration and composition in green herb were related to leaf area index and N concentration in the...

During the last five decades, a number of combinatorial generalizations and interpretations have occurred for the identities of the Rogers-Ramanujan type. The object of this paper is to give a most general known analytic auxiliary functional generalization which can be used to give combinatorial interpretations of generalizedq-identities of the Rogers-Ramanujan type. The derivation realise the theory of basic hypergeometric series with two unconnected bases.

Nano structuring of silicon surface by low energy ion irradiation is reported. Semi insulating n‐Si (100) has been irradiated by 50 keV Ar+ ion beam at an angle of 50° with respect to surface normal. The irradiated sample’s surfaces were analyzed by Atomic Force Microscopy. Irradiation caused formation of nano‐sized elliptical dots aligned in rows perpendicular to ion beam direction at fluence of 1×1017 ions/cm2. At higher fluences of 3×1017 ions/cm2 and 7×1017 ions/cm2 self organized ripples were developed on the surface.

Mehra, U.R., Challa, J. and Singh, U.B. 1993. Nutrient utilisation and rumen fermentation pattern in buffaloes fed rations supplemented with formaldehyde treated urea molasses mineral blocks. J. Appl. Anim. Res., 4: 67–72. To overcome the problem of hygroscopic nature of urea molasses mineral blocks (UMMB), formaldehyde and phosphoric acid were added to these (FUMMB). Eight postulated male buffaloes weighing around 350 kg were divided into two groups and were offered the UMMB without or with formaldehyde and phosphoric acid as a lick. One kg wheat bran and ad libitum wheat straw were fed individually. The UMMB contained 37 parts sugarcane molasses, 10 parts each of urea, cement and fish meal, 32 parts wheat bran, 1 part common salt and 0.1 part vitablend. Besides these, 225 ml formaldehyde and 45 ml phosphoric acid per 100 kg block were added to FUMMB. Dry matter intake, digestibility and rumen fermentation pattern were similar in both the groups. As FUMMB was not found to be hygroscopic, it is r...

Pneumocystis jiroveci (also known as P. carinii) causes fatal pneumonia in patients with AIDS and other immunocompromised patients. Co-trimoxazole (trimethoprim + sulphamethoxazole, TMP-SMZ) is the drug of choice for treatment and prophylaxis. Widespread use of sulpha medication has raised the possible selection of resistant P. jiroveci strains worldwide. Non-synonymous polymorphisms associated with sulpha resistance have been observed in P. jiroveci dihydropteroate synthase (DHPS) gene at codons 55 and 57. In view of this, we investigated mutation at DHPS locus amongst P. jiroveci isolates obtained at a tertiary care hospital in north India.Microscopic examination of P. jiroveci in 69 clinical samples obtained from patients suspected to have P. carinii pneumonia (PCP), was performed by Grocott's Gomori methenamine silver and direct fluorescent antibody staining. Molecular studies were carried out by polymerase chain reaction (PCR) using major surface glycoprotein (MSG) as the target gene. Investigations for DHPS mutations were carried at specific 55th and 57th codon using PCR-RFLP (restriction fragment length polymorphism) assay.Microscopic examination detected P. jiroveci in four cases and MSG gene was amplified in five cases. Further, amplification of DHPS gene was successful in four of the five cases positive by MSG gene PCR. No point mutation was observed and all four isolates presented wild-type sequences at DHPS gene by RFLP analysis.Although our findings suggest that in Indian subpopulation, point mutations in DHPS gene of P. jiroveci are not as common as in other parts of the developed world, further studies are needed.

Twenty male buffalo calves of about 9–13 months of age were divided at random into five groups of four animals each. All the animals were individually offered wheat bhoosa (chopped straw) ad libitum and wheat bran and oil-extracted rice bran each at 500 g day−1. Calves of Groups 2, 3, 4 and 5 were given urea molasses mineral block (UMMB as lick) ad libitum. In addition, calves of Groups 3, 4 and 5 were supplemented with fish meal at the rate of 50, 100 and 150 g, respectively. The UMMB contained 38% molasses, 10% urea, 10% cement, 40% wheat bran, 1% salt and 1% mineral mixture. After a feeding period of 130 days, a metabolism trial of 7 days duration was conducted. The average daily dry matter intake was higher (P It may be concluded that the prevailing practice in the rural areas of developing countries of keeping growing calves solely on wheat bhoosa and a small amount of poor-grade concentrate is not satisfactory. This feed can be economically supplemented with UMMB and 100 g fish meal to maintain a fairly good growth rate for the calves.

The effect of small amounts of fish meal on the utilization of ammoniated wheat bhoosa (chopped straw) was examined in seven groups of three buffalo calves. All animals were offered ammoniated wheat straw (69.5%) mixed manually with molasses (29%), common salt (0.5%), a mineral supplement (1.0%) and a vitamin supplement (25 g (100 kg)−1 feed) which was compressed into a block weighing 6–7 kg. The blocks were supplemented with fish meal at the rate of 0, 25, 50, 100 or 200 g day−1; two additional groups received 25 or 50 g fish meal day−1 and 500 g oil-extracted rice bran per animal. A metabolism trial of 7 days duration was conducted at the end of a 95-day feeding trial. Dry matter intake was significantly increased in animals supplemented with fish meal. There were no significant differences in the digestibility of nutrients. Daily live weight gains were 105, 125, 209, 230 and 301 g in the groups offered increasing quantities of fish meal and 323 and 389 g in the groups offered 25 and 50 g fish meal and rice bran. It is concluded that a complete feed block containing ammoniated wheat straw, molasses, minerals, salts, vitamins and a small amount of bypass protein is suitable for animals experiencing drought and famine. The blocks occupy less space than uncompressed feed and are easy to handle and store.

The past decade has seen a rapid expansion of directly observed treatment, short-course (DOTS) centers throughout India, under the guidance of the Revised National Tuberculosis Control Programme (RNTCP). While expansion has been rapid and extensive, few reports exist detailing individual DOTS centers' experiences, their challenges, and their successes. We present a brief report on the status of a DOTS center being run at a large tertiary care center in northern India for almost four years (2001-2005).The DOTS center followed RNTCP guidelines for the evaluation and treatment of suspected TB cases. A register carrying detailed information of all patients seen at the DOTS center was kept by the senior clinician. Data from this register were extracted and analyzed for descriptive measures.A total of 1490 patients were evaluated. Of the 768 patients with cough, 27 per cent (211) were found to be sputum positive for acid-fast bacilli (AFB). Among patients who were initiated on anti-tuberculosis medications, cure was achieved in 92 per cent (71 of 77) of new sputum smear positive patients; treatment completion was achieved in 91 per cent (91 of 100) of extrapulmonary TB (EPTB) and 75 per cent (46 of 61) of sputum-negative pulmonary TB patients. Overall treatment success was achieved in 86 per cent (229 of 266).Treatment results were in keeping with the RNTCP guidelines. Tertiary care centers appear to be excellent place for education of medical students and operational research. The latter is much needed, as HIV-TB co-infection, multi-drug resistant TB, and EPTB continue to be major public health threats even in the era of DOTS.

In 1993, Government of India started the Revised National Tuberculosis Control Programme (RNTCP). A model Directly Observed Therapy, Short-Course (DOTS) centre was established at the All India Institute of Medical Sciences (AIIMS) to (i) identify the challenges and opportunities in establishing DOTS centres at tertiary care facilities, (ii) to teach the strategies of RNTCP to medical and paramedical staff, and (iii) to undertake relevant operational research connected with tuberculosis (TB) treatment and control. In this communication, we describe the experience of establishing a DOTS centre at India's premier medical institute and discuss the lessons learned.Since September 2001 through November 2002 AIIMS employees and their dependants diagnosed with tuberculosis were enrolled for treatment at AIIMS DOTS centre. One hundred sixty-eight patients were diagnosed as suffering from tuberculosis. Of these 49 patients were referred out and remaining 119 patients were treated at AIIMS DOTS centre.Treatment success was achieved in 80% (20/25) of new smear positive cases and the DOTS centre achieved other targets set up by the RNTCP. As the results of the pilot study at AIIMS DOTS centre were favourable, the facilities of AIIMS DOTS centre were extended to the general public from September 2002 onwards.Despite tremendous patient load at tertiary care facilities, it is possible to achieve targets established by the RNTCP. However, additional research needs to be conducted especially relating to drug resistance and surrogate markers of failure under RNTCP.

Dengue fever (DF) is endemic in India and dengue hemorrhagic fever (DHF) has been reported with increasing frequency in the last decade. We evaluated three commercial assays for detection of antibodies to dengue virus, to assess their performance in a diagnostic laboratory. Sera from 58 patients collected during a febrile outbreak in New Delhi in 1997 were studied. The methods evaluated were MRL Diagnostic Dengue Fever Virus IgM Capture ELISA, Pan Bio Dengue Duo IgM and IgG Capture ELISA and Pan Bio Rapid Immunochromatographic test. The MRL ELISA correctly identified 97.8% (43 of 44) of samples as dengue positive while the Pan Bio Duo ELISA and Pan Bio RIT identified 95.45% (42 of 44). The sensitivities of both Pan Bio Duo ELISA and Pan Bio RIT for primary dengue and secondary dengue were 100% and 93.54% respectively. The specificity of three assays were MRL IgM ELISA 100%, Pan Bio Duo ELISA 92.8% and Pan Bio RIT 85.7%.

The present study comprised of three genotypes (V1-Naveen 2000+, V2-Sun-7711 and V3-Solan Lalima), three mulches (M0-No mulch, M1-Pine needle mulch and M2-black polyethylene) and three biofertilizers (B0-recommended NPK, B1-100% NPK+Azotobacter (1 g plant−1)+PSB (1 g plant−1) and B2-75% NPK+Azotobacter (1 g plant−1)+PSB (1 g plant−1). Thus, there were 27 treatment combinations which were replicated thrice in split-split plot design. Among varieties, number of days to first flowering and first harvest and maximum yield was observed with the variety V2 (Sun-7711). Among the mulch materials and biofertilizers, M2 (Black polythene) and B1 (100% NPK+Azotobacter (1 g plant−1)+PSB (1 g plant−1) were recorded to be the best regarding number of days to first flowering and first harvest and fruit yield. The first order interactions viz., varieties×mulch, biofertilizers×mulch and varieties×biofertilizers significantly affected most of the characters under study. Maximum fruit yield was obtained with treatment combinations of V2M2 (Sun-7711 applied with black polyethylene mulch), B2M2 (75% NPK+Azotobacter (1 g plant−1)+PSB (1 g plant−1) applied with black polyethylene mulch) and V2B2 (Sun-7711 with 75% NPK+Azotobacter (1 g plant−1)+PSB (1 g plant−1). Further in three factor interaction, the highest fruit yield (1037.33 q ha−1) was obtained with the treatment combination of Sun-7711, 75% NPK+Azotobacter (1 g plant−1)+PSB (1 g plant−1) and black polyethylene mulch (V2B2M2).

The recent emergence of dengue hemorrhagic fever/dengue shock syndrome (DHF/ DSS) in India has been a source of concern. In the present study a quantitative comparison of 406 nucleotide long sequence from the capsid-premembrane junction region (C-PrM) of 9 dengue virus type 2 (DEN-2) isolates from Delhi with 10 DEN-2 isolates from diverse geographic areas provided sufficient information for estimating genetic relationships. The data indicated that the 1996 epidemic of DHF in Delhi was caused by genotype IV strains of DEN-2. This genotype, perhaps, displaced genotype V strains of DEN-2, which was circulating genotype in 1967. The period during which this displacement had occurred is not clear from the present study. Nonetheless, similar experience in four countries in Latin America and in Sri Lanka suggest that the introduction of new genotypes of DEN-2 displacing the circulating genotype may be associated with the appearance of DHF/DSS. More work is required to elucidate this hypothesis. Transitions at nucleotide positions 406 and 431 resulted in amino acid substitutions near (aa position 104, methionine --valine) and at the hinge region (aa position 112, valine --alanine) of C-PrM, respectively in all/most genotypes of group III and IV DEN-2 viruses analysed. Most of these virus strains have been isolated from DHF/DSS outbreaks. Significance of this observation is discussed. The data presented in this study suggest the utility of C-PrM sequence analysis for molecular epidemiology of dengue viruses.

Volatile fatty acid (VFA) production rates were measured by isotope dilution technique in the rumen of buffalo calves fed on wheat straw plus concentrate, green maize, cow pea and berseem. Correlations derived between the VFA production rates and their concentration and DOM were significant except in animals fed on cow pea. The VFA production rates were also significantly correlated with the TDN intake in all the four feeds tested. The regression equations obtained for the four feeds were different, which suggested that VFA production may vary with the quantity and quality of feed digested. These experiments suggest the use of different regression equations for different feeds.

SUMMARYA technique is described for thein vivoestimation of the rate of production of bacteria in the rumen of buffalo calves. The animals were given their daily ration in 12 equal amounts at 2-h intervals. The bacterial cells from the rumen were labelled either with14C or36S byin vitroincubation in the presence of [U-14C]DL-leucine or35S-sodium sulphate. Labelled bacterial cells were injected in a single dose into the rumen. Samples of the ruminal fluid were drawn at various time intervals for 9 h and the specific radio-activity of the bacteria determined. The dilution in the specific radioactivity was used to calculate the turn-over time and rates of production of bacteria in the rumen. The average turnover time was 308 min. The production rate of bacteria averaged 211 mg/min (20·3 g/mole VFA produced).