Nano-compositional imaging of the lanthanum silicide system at THz wavelengths

Terahertz scattering-type scanning near-field optical microscopy (THz-sSNOM) provides a noninvasive way to probe the low frequency conductivity of materials and to characterize material compositions at the nanoscale. However, the potential capability of atomic compositional analysis with THz nanoscopy remains largely unexplored. Here, we perform THz near-field imaging and spectroscopy on a model rare-earth alloy of lanthanum silicide (La-Si) which is known to exhibit diverse compositional and structural phases. We identify subwavelength spatial variations in conductivity that is manifested as alloy microstructures down to much less than 1 μm in size and is remarkably distinct from the surface topography of the material. Signal contrasts from the near-field scattering responses enable mapping the local silicon/lanthanum content differences. These observations demonstrate that THz-sSNOM offers a new avenue to investigate the compositional heterogeneity of material phases and their related nanoscale electrical as well as optical properties.

Comparative evaluation of native top feeds of western Himalayas for utilization as goat's ration in mash and block form

The current research was undertaken to scrutinize the effect of leaf meal mixture as concentrate mixture in the ration of goats. Leaf meal mixture (LMM) was prepared using equal quantities of ten top-foliages namely Acacia nilotica, Celtis australis, Ficus palmata, Ficus religiosa, Grewia optiva, Melia azadarach, Morus alba, Quercus incana, Salix alba and Zizyphus jujube obtained from district Poonch of Jammu region in western Himalayas. The LMM prepared was substituted for 15% in the concentrate mixture being fed to the goats. The study constituted of two trials. Concentrate mixture offered to the animals was in mash and multi-nutrient block in first and second trial respectively. A total of twelve non-descript, adult male goats were selected for each trial. Goats of 0-14 months age (27.71 ± 2.96 kg live body weight) of for first trial while goats of 12-16 months age (27.02 ± 2.93 kg live weight) for second trial were divided into control and treatment groups as per randomized block design and fed ad-lib wheat straw and concentrate mixture @ (20 g/kgW0.75). No significant variation was observed (p > 0.05) in body weight, feed and DM intake among all groups in both trials. Comparable intake as well as digestibility of various nutrients like DM, OM, CP, EE, CF, NFE, NDF, ADF and TDN were found between the two groups during individual trials. There was a positive nitrogen, calcium and phosphorus balance among all experimental animals in both the trials. Serum enzymes ALT, AST and haemato-biochemical parameters like total protein, albumin, globulin, albumin: globulin and blood urea nitrogen (BUN) showed no significant differences during both trials in all groups, being within normal physiological levels. However, haemoglobin concentration was significantly higher (P < 0.05) in treatment group with respect to the control group in first trial. On the basis of current results, it can be established that leaf meal mixture can successfully be used to replace concentrate mixture up to 15% in the ration of goats without expecting any adverse impacts on their growth and overall health.

Spent marigold flower meal as an alternate feed for goats

This research trial is aimed to study the nutritional qualities and significance of feeding spent marigold flower meal (SMFM) in goats. SMFM and diet containing iso-nitrogenous concentrate mixture with different levels of spent marigold flower meal (0-30%) were studied for in vitro degradation. Depending upon the in vitro results, concentrate mixture containing 15% level of SMFM was selected for in vivo trial. In vivo studies were conducted for a period of 60 days, and 12 local, non-descript, adult male goats (10-14 months age; 31.09 ± 2.91 kg body weight) were randomly assigned to two groups and were fed on ad libitum wheat straw with either conventional (control) or SMFM containing concentrate mixture (treatment). Results of the study showed that there was no variation in body weight of the goats between periods and between groups. DM and OM intake along with their digestibility were similar among the two groups. The digestibility of all other nutrients was comparable between the two groups. Nitrogen, calcium and phosphorus balance were positive in both the groups without any significant disparity. Moreover, experimental goats did not differ in biochemical parameters, without any significant difference between periods and dietary treatments except AST level which was significantly higher (P > 0.05) in treatment group. So, this study successfully demonstrates that SMFM could be incorporated in the concentrate mixture, up to 15% without any discernable difference in the performance of goats.

Magnetic ground states of Ce3TiSb5, Pr3TiSb5and Nd3TiSb5determined by neutron powder diffraction and magnetic measurements

TheR₃TiSb₅ternary compounds, withRa light rare earth (La to Sm) have been reported to crystallize with the anti-Hf₅CuSn₃-type hexagonal structure (Pearson's symbolhP18; space-groupP6₃/mcm, N. 193). An early article that reported possible superconductivity in some of these intermetallic phases (namely those withR= La, Ce, and Nd) caught our attention. In this work, we have now refined the crystal structure of theR₃TiSb₅compounds withR= Ce, Pr and Nd by Rietveld methods using high-resolution neutron powder diffraction data. The magnetic ground states of these intermetallics have been investigated by low-temperature magnetization and high-intensity neutron diffraction. We find two different magnetic transitions corresponding to two related magnetic structures atT_N1= 4.8 K (k₁= [0, 1/2, 1/8]) andT_N2= 3.4 K (k₂= [0, 0, 1/8]), respectively for Ce₃TiSb₅. However, the magnetic ordering appears to occur following a peculiar hysteresis: thek₂-type magnetic structure develops only after thek₁-type phase fraction has first slowly ordered with time and the size of the ordered Ce³⁺magnetic moment has become large enough to induce the second magnetic transition. AtT= 1.5 K the maximum amplitude of the Ce moment in the coexisting phases amounts toμ_Ce= 2.15 μ_B. For Nd₃TiSb₅an antiferromagnetic ordering belowT_N= 5.2 K into a relatively simpler commensurate magnetic structure with a magnetic moment ofμ_Nd= 2.14(3)μ_Band magnetic propagation vector ofk= [0, 0, 0], was determined. No evidence of superconductivity has been found in Nd₃TiSb₅. Finally, Pr₃TiSb₅does not show any ordering down to 1.5 K in neutron diffraction while an antiferromagnetic ground state is detected in magnetization measurements. There is no sign of magnetic contribution from Ti atoms found in any of the studied compounds.

Sensitivity Enhancement of a Concave Shaped Optical Fiber Refractive Index Sensor Covered with Multiple Au Nanowires

In the present paper, a new kind of concave shaped refractive index sensor (CSRIS) exploiting localized surface plasmon resonance (LSPR) is proposed and numerically optimized. The LSPR effect between polaritons and the core guided mode of designed CSRIS is used to enhance the sensing performance. The sensor is characterized for two types of sensing structures coated with gold (Au) film and Au nanowires (AuNWs), respectively. The influence of structural parameters such as the distance (D) of the concave shaped channel (CSC) from the core, the diameter of the nanowire (d_n) and the size (s) of the CSC are investigated here. In comparison to Au film, the AuNWs are shown to significantly enhance the sensitivity and the performance of the designed sensor. An enhanced sensitivity of 4471 nm/RIU (refractive index unit) is obtained with AuNWs, for a wide range of analytes refractive index (n_a) varying between 1.33 to 1.38. However, for conventional Au film; the sensitivity of 808.57 nm/RIU is obtained for the same range of analytes.

Improved thermomechanical and electrical properties of reduced graphene oxide reinforced polyaniline - dodecylbenzenesulfonic acid/divinylbenzene nanocomposites

HYPOTHESIS

Various efforts are going on to improve the electrical properties of carbon fiber reinforced polymer (CFRP) composites. Conducting polymer is one the promising material to achieve the desired electrical properties of CFRP composites without compromising the mechanical properties as a lighting sticking material.

EXPERIMENTS

In present study, in addition to conducting polymer polyaniline (PANI), another conducting phase reduced graphene oxide (RGO) was incorporated in PANI based system. The RGO was synthesized and incorporated in different weight (0-0.5 wt%) fraction in dodecylbenzenesulfonic acid (DBSA) doped PANI-divinylbenzene (DVB) polymer to get PANI-DBSA/DVB nanocomposite. The mechanical and interfacial interaction was analyzed by universal testing machine (UTM) and transmitted electron microscopy (TEM).

FINDINGS

The addition of optimum 0.3 wt% RGO improved flexural strength and modulus of PANI-DSBA/RGO-DVB composite by 153% and 32% respectively over neat PANI-DBSA/DVB nanocomposite. The maximum electrical conductivity 0.301 S/cm, glass transition temperature (T_g) and thermal stability of nanocomposite realized at 0.3 wt% of RGO. Raman spectroscopy and HRTEM confirmed the improvement of interfacial bonding by H-bonding and π-π interaction. For the 1st time we are reporting RGO utilisation for the improvement of thermomechanical and electrical interfacial properties of PANI-DBSA/DVB nanocomposite for the structural applications.

Non-hysteretic first-order phase transition with large latent heat and giant low-field magnetocaloric effect

First-order magnetic transitions (FOMTs) with a large discontinuity in magnetization are highly sought in the development of advanced functional magnetic materials. Isosymmetric magnetoelastic FOMTs that do not perturb crystal symmetry are especially rare, and only a handful of material families, almost exclusively transition metal-based, are known to exhibit them. Yet, here we report a surprising isosymmetric FOMT in a rare-earth intermetallic, Eu₂In. What makes this transition in Eu₂In even more remarkable is that it is associated with a large latent heat and an exceptionally high magnetocaloric effect in low magnetic fields, but with tiny lattice discontinuities and negligible hysteresis. An active role of the Eu-5d and In-4p states and a rather unique electronic structure borne by In to Eu charge transfer, altogether result in an unusual exchange mechanism that both sets the transition in motion and unveils an approach toward developing specific magnetic functionalities ad libitum.

Crystal, magnetic, calorimetric and electronic structure investigation of GdScGe1-x Sb x compounds

Experimental investigations of crystal structure, magnetism and heat capacity of compounds in the pseudoternary GdScGe-GdScSb system combined with density functional theory projections have been employed to clarify the interplay between the crystal structure and magnetism in this series of RTX materials (R  =  rare-earth, [Formula: see text]  =  transition metal and X  =  p-block element). We demonstrate that the CeScSi-type structure adopted by GdScGe and CeFeSi-type structure adopted by GdScSb coexist over a limited range of compositions [Formula: see text]. Antimony for Ge substitutions in GdScGe result in an anisotropic expansion of the unit cell of the parent that is most pronounced along the c axis. We believe that such expansion acts as the driving force for the instability of the double layer CeScSi-type structure of the parent germanide. Extensive, yet limited Sb substitutions [Formula: see text] lead to a strong reduction of the Curie temperature compared to the GdScGe parent, but without affecting the saturation magnetization. With a further increase in Sb content, the first compositions showing the presence of the CeFeSi-type structure of the antimonide, [Formula: see text], coincide with the appearance of an antiferromagnetic phase. The application of a finite magnetic field reveals a jump in magnetization toward a fully saturated ferromagnetic state. This antiferro-ferromagnetic transformation is not associated with a sizeable latent heat, as confirmed by heat capacity measurements. The electronic structure calculations for [Formula: see text] indicate that the key factor in the conversion from the ferromagnetic CeScSi-type to the antiferromagnetic CeFeSi-type structure is the disappearance of the induced magnetic moments on Sc. For the parent antimonide, heat capacity measurements indicate an additional transition below the main antiferromagnetic transition.

Effect of condensed tannins from Ficus infectoria and Psidium guajava leaf meal mixture on nutrient metabolism, methane emission and performance of lambs

Objective

The study examined the effect of condensed tannins (CT) containing Ficus infectoria and Psidium guajava leaf meal mixture (LMM) supplementation on nutrient metabolism, methane emission and performance of lambs.

Methods

Twenty four lambs of ~6 months age (average body weight 10.1±0.60 kg) were randomly divided into 4 dietary treatments (CT-0, CT-1, CT-1.5, and CT-2 containing 0, 1.0, 1.5, and 2.0 percent CT through LMM, respectively) consisting of 6 lambs each in a completely randomized design. All the lambs were offered a basal diet of wheat straw ad libitum, oat hay (100 g/d) along with required amount of concentrate mixture to meet their nutrient requirements for a period of 6 months. After 3 months of experimental feeding, a metabolism trial of 6 days duration was conducted on all 24 lambs to determine nutrient digestibility and nitrogen balance. Urinary excretion of purine derivatives and microbial protein synthesis were determined using high performance liquid chromatography. Respiration chamber study was started at the mid of 5th month of experimental feeding trial. Whole energy balance trials were conducted on individual lamb one after the other, in an open circuit respiration calorimeter.

Results

Intake of dry matter and organic matter (g/d) was significantly (p<0.05) higher in CT-1.5 than control. Digestibility of various nutrients did not differ irrespective of treatments. Nitrogen retention and microbial nitrogen synthesis (g/d) was significantly (p<0.01) higher in CT-1.5 and CT-2 groups relative to CT-0. Total body weight gain (kg) and average daily gain (g) were significantly (linear, p<0.01) higher in CT-1.5 followed by CT-1 and CT-0, respectively. Feed conversion ratio (FCR) by lambs was significantly (linear, p<0.01) better in CT-1.5 followed by CT-2 and CT-0, respectively. Total wool yield (g; g/d) was linearly (p<0.05) higher for CT-1.5 than CT-0. Methane emission was linearly decreased (p<0.05) in CT groups and reduction was highest (p<0.01) in CT-2 followed by CT-1.5 and CT-1. Methane energy (kcal/d) was linearly decreased (p<0.05) in CT groups.

Conclusion

The CT supplementation at 1% to 2% of the diet through Ficus infectoria and Psidium guajava LMM significantly improved nitrogen metabolism, growth performance, wool yield, FCR and reduced methane emission by lambs.

Role of limited hydrogen and flow interval on the growth of single crystal to continuous graphene by low-pressure chemical vapor deposition

A method for defect-free large crystallite graphene growth remains unknown despite much research effort. In this work, we discuss the role of flow duration of H₂ gas for the production of graphene as per requirement and production at a minimum flow rate considering the safety issue of hydrogen utilization. The copper substrate used for growth was treated for different time intervals (0 to 35 min) in H₂ flow prior to growth. Structural and chemical changes occurring in the copper substrate surface were probed by grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy. The results were correlated with the Raman spectroscopy data, which can quantify the quality of graphene. With increasing H₂ flow interval, secondary nucleation sites were observed and growth favored few-layer graphene structures. The surface-adsorbed oxygen molecules and its conversion to an OH terminated surface with increasing hydrogen flow interval was found to be a key factor in enhancing nucleation density. The Stranski-Krastanov type of nucleation was observed for samples grown with different time intervals of H₂ treatment, except 5 min of H₂ flow prior to growth for which the Volmer-Weber type of growth favored monolayer graphene crystallite growth.

Tetragonal to triclinic structural transition in the prototypical CeScSi induced by a two-step magnetic ordering: a temperature-dependent neutron diffraction study of CeScSi, CeScGe and LaScSi

An investigation on the ground state magnetism of CeScSi, CeScGe (tetragonal CeScSi-type, tI12, space group I4/mmm) by temperature-dependent powder neutron diffraction has been carried out, as debated and controversial data regarding the low temperature magnetic behaviours of these two compounds were reported. Our studies reveal that, while cooling, long-range magnetic ordering in CeScSi and CeScGe takes place by a two-step process. A first transition leads to a magnetic structure with the Ce moments aligned ferromagnetically onto two neighbouring tetragonal basal a-b planes of the CeScSi-type structure; the double layers are then antiferromagnetically coupled to each other along the c-axis. The transition temperature associated with the first ordering is T _N ~ 26 K and T _N ~ 48 K for the silicide and the germanide, respectively. Here the spin directions are rigorously confined to the basal plane, with values of the Ce magnetic moments of μ _Ce  =  0.8-1.0 μ _B. A second magnetic transition, which takes place at slightly lower temperatures, results in a canting of the ordered magnetic moments out of the basal plane which is accompanied by an increase of the magnetic moment value of Ce to μ _Ce  =  1.4-1.5 μ _B. Interestingly, the second magnetic transition leads to a structural distortion in both compounds from the higher-symmetry tetragonal space group I4/mmm to the lower-symmetry and triclinic I-1 (non-standard triclinic). Magnetic symmetry analysis shows that the canted structure would not be allowed in the I4/mmm space group; this result further confirms the structural transition. The transition temperatures T _S from I4/mmm to I-1 are about 22 K in CeScSi and 36 K in CeScGe, i.e. well below the temperature of the first onset of antiferromagnetic order observed in this work (or below the ordering temperature, previously reported as either T _C or T _N). This result, along with the synchronism of the magnetic and structural transitions, suggests a magnetostructural origin of this structural distortion. We have also carried out powder neutron diffraction for LaScSi as a non-magnetically-ordering reference compound and compared the results with those of CeScSi and CeScGe compounds.

Modelling of microalgal growth and lipid production in Dunaliella tertiolecta using nitrogen-phosphorus-potassium fertilizer medium in sintered disk chromatographic glass bubble column

A comprehensive mathematical model involving NPK-10:26:26 fertilizer, NaCl, NaHCO3, light and temperature operating variables for Dunaliella tertiolecta cultivation is formulated to predict microalgae-biomass and lipid productivity. Proposed model includes Monod/Andrews kinetics for the absorption of essential nutrients into algae-biomass and Droop model involving internal nutrient cell quota for microalgae growth, assuming algae-biomass is composed of sugar, functional-pool and neutral-lipid. Biokinetic model parameters are determined by minimizing the residual-sum-of-square-errors between experimental and computed microalgae-biomass and lipid productivity using genetic algorithm. Developed model is validated with the experiments of Dunaliella tertiolecta cultivation using air-agitated sintered-disk chromatographic glass-bubble column and the effects of operating variables on microalgae-biomass and lipid productivity is investigated. Finally, parametric sensitivity analysis is carried out to know the sensitivity of model parameters on the obtained results in the input parameter space. Proposed model may be helpful in scale-up studies and implementation of model-based control strategy in large-scale algal cultivation.

Effect of tanniferous leaf meal based multi-nutrient blocks on feed intake, hematological profile, immune response, and body weight changes in Haemonchus contortus infected goats

Aim:

The aim was to assess the effect of multi nutrient block (MNB) supplementation with and without tanniferous leaf meal mixture on feed intake, hematological profile, immune response, and body weight changes of goats that were experimentally infected with Haemonchus contortus.

Materials and Methods:

Total 12 adult male goats of similar age and body weight (26.49±0.87) were allocated in 3 groups in completely randomized design. MNB supplemented in first two groups i.e. in T₁ (no infection) and T₂ (H. contortus infection @ 1500 L₃/goat) group, while, MNB-condensed tannin (CT) supplemented in T₃ (H. contortus infection @ 1500 L₃/goat + CT source). All goats were fed concentrate mixture @ 100 g/day/goat, ad lib wheat straw and MNB or MNB-CT to meet their requirement for maintenance. Body weights were recorded and blood and fecal samples were collected at 0 day and thereafter at 15 days intervals for a period of 75 days for the assessment of body weight changes, hematological profile and H. contortus loads. Both humoral and cell-mediated immune (CMI) response were assessed at the end of feeding trial.

Results:

Mean hemoglobin and packed cell volume (PCV) levels were found to be highest (p<0.001, p<0.05) in T₁ group followed by T₃ group and lowest values were observed in T₂ group. However, The PCV values between T₁ and T₃ groups were found to be statistically non-significant (p<0.05). The humoral and CMI response were significantly (p<0.036) higher in T₃ group as compared to T₂ group. MNB-CT supplementation significantly (p<0.001) reduced fecal egg counts in T₃ group as compared to MNB supplemented T₂ group.

Conclusion:

Supplementation of MNB-CT could be used as an alternative sustainable method to control H. contortus and maintained health status and performance of goats in face of parasitic challenge.

Prevalence of lymphatic filariasis in a tea garden worker population of Dibrugarh (Assam), India after six rounds of mass drug administration

BACKGROUND & OBJECTIVES

Lymphatic filariasis (LF) is endemic in the state of Assam and mass drug administration (MDA) programme for LF elimination is being implemented in the state since 2004. A study on prevalence of microfilaria (mf), disease endemicity and vector infection was carried out in a tea garden population of Dibrugarh, Assam (India) to assess the effect of ongoing MDA programme on elimination of LF.

METHODS

Finger prick thick blood smears (20 mm3) were made from individuals aged ≥2 yr old during night blood survey in between 2000-0000 hrs during the period of November 2012 to February 2013. Blood smears were dehaemoglobinised, stained with Giemsa and examined under microscope for presence of mf. Indoor resting mosquitoes were collected during 0600-1000 hrs and female Culex quinquefasciatus were dissected and examined under microscope for larval forms of the parasite.

RESULTS

A total of 634 blood smears were collected and screened for mf and 47 (7.41%) individuals were found microfilaraemic, with predominance of males (74.5%). Highest mf rate (20.0%) was seen in the males of 30-39 yr age group while in females, age group of 10-19 yr recorded maximum mf rate (5.48%). Entomological collection and dissection of Cx. quinquefasciatus revealed presence of larval stages of the parasite and infection and infectivity rates recorded were 13.20 and 3.70%, respectively. Chronic clinical manifestations in the form of elephantiasis and hydrocele were recorded in 33 (5.73%) subjects of the 575 examined.

INTERPRETATION & CONCLUSION

Mass drug administration data showed six rounds of MDA with drug distribution coverage in between 63.42 and 95.93% in the study population. Out of 634 individuals examined 47 were found microfilaraemic giving an overall infection rate of 7.41%. Mosquito vector infection and infectivity rates were 13.20 and 3.70%, respectively. Presence of high mf rate, vector infectivity rate and clinical cases in the study population after six rounds of MDA warrants concerted efforts to be made for effective implementation and monitoring of MDA for success of LF elimination programme.

Microfilarial periodicity of Wuchereria bancrofti in Assam, Northeast India

BACKGROUND & OBJECTIVES

Wuchereria bancrofti has shown nocturnal periodicity in India and other endemic countries of the world except pacific regions where non-periodic or diurnal sub-periodic forms have been reported. Presence of sub-periodic form of W. bancrofti in Andaman and Nicobar Islands, India and a case report of sub- periodic form of W. bancrofti from Mysore, India provide basis for exploring the periodicity pattern of microfilaria of W. bancrofti prevalent in Assam, Northeastern region of India. State of Assam has unique geographical location as its Northeastern region shares international boundaries with Nepal, China, Bhutan, Myanmar and Bangladesh. Evolutionary association of W. bancrofti found in Assam is not known and possibility of its link with W. bancrofti form, prevalent in neighbouring countries may not be ruled out. Hence, this study was undertaken to know the microfilarial periodicity of W. bancrofti in Assam.

METHODS

Ten microfilaria positive adult male individuals having moderate to high microfilaraemia were selected. Informed written consent from each participant was obtained. The presence of microfilaria was observed at two hourly intervals over a period of 24 h using 50 μl of finger prick peripheral blood samples. Peripheral blood smears were processed, stained and examined under microscope and microfilaria counts were recorded.

RESULTS

Data collected were calculated and analyzed using modified statistical method, and the periodicity curve was prepared. Typical nocturnal periodicity was observed at a peak time of 0003 hrs with a periodicity index of 136.2.

INTERPRETATION & CONCLUSION

Analysis of the data revealed nocturnal periodicity of the W. bancrofti prevalent in the Assam with peak periodicity about one hour ahead of the other states in India. Findings will be helpful in evaluation and monitoring of ongoing MDA programme for elimination of LF in Assam.

Length weight relationship and condition factor of selected freshwater fish species found in river Ganga, Gomti and Rapti, India

This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rite rita, Sperato seenghala, Sperota aor, Mostacembalus armatus, Macrognathus puncolus, Gudusia chopra, Clupisoma garua, Puntius sophore, Puntius ticto, Rasbora daniconius, Amblypharyngodon mole, Chanda noma, Colisa fociatus and Colisa sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at p< 0.001. The condition factor (K) varied considerably from 0.76 and 2.95, with a mean K = 1.43 which may be attributed to different environmental conditions of the river basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries.

Instability range of microsolvated multiply charged negative ions: prediction from detachment energy of stable hydrated clusters

We have presented a first-principle theory-based derivation of an exact expression for the solvent number-dependent electron-detachment energy of a solvated species in the thermodynamic limit. We also propose a generalized equation bridging the electron detachment energies for small and infinitely large clusters, thus providing a new route to calculate the ionization potential of a negatively charged ion from the electron-detachment energies of its stable hydrated clusters. Most importantly, it has the ability to predict the instability range of microhydrated anions. The calculated results for the ionization potential for a number of ions are found to be in good agreement with the available experimental results, and the predicted instability range for the doubly charged anions SO₄²⁻ and C₂O₄²⁻ is also consistent with experimental and ab initio results.

2-Azetidinone--a new profile of various pharmacological activities

2-azetidinone, a β-lactam four member heterocyclic compound involved in research aimed to evaluate new products that possess interesting biological activities. These compounds reported for their antimicrobial and antifungal activities. Successful introduction of aztreonam as a potent inhibitor of cephalosporinase and ezetimibe as a cholesterol absorption inhibitor proved potential of 2-azetidinone moiety. Subsequently 2-azetidinones were highlighted as a potent mechanism based inhibitor of several enzymes like human tryptase, chymase, thrombin, leukocyte elastase, human cytomegalovirus protease and serine protease enzyme. These derivatives also known to possess antitubercular, anti-inflammatory, antitumor, anti-HIV, antiparkinsonian, antidiabetic and vasopressin V1a antagonist activity. The present review article focuses on the pharmacological profile of 2-azetidinones with their potential activities.

Influence of an enzyme cocktail and phytase individually or in combination in Ven Cobb broiler chickens

1. An experiment (21 d) was conducted to determine if the response of chicks to a cocktail of xylanase, amylase, and protease (XAP) or Escherichia coli-derived phytase individually or in combination when fed a nutritionally marginal maize-soybean meal diet is age-dependent. 2. A total of 250 one-day-old Ven Cobb broiler chicks were allocated to 5 dietary treatments in a randomised complete block design. The treatments were as follows: (1) positive control with supplemental inorganic P; (2) negative control (NC) marginal in P and ME; (3) NC plus XAP to provide (per kg of diet) 650, 1650 and 4000 U of xylanase, amylase, and protease, respectively; (4) NC plus phytase added to provide 1000 phytase units/kg; and (5) NC plus a combination of XAP and phytase. 3. Low ME and P in the NC diet depressed weight gain and gain:feed. A cocktail of XAP alone did not improve performance, but phytase supplementation improved weight gain. The enzymes were additive in their effects on growth performance. 4. The enzymes had no effect on ileal digestible energy. Ileal N digestibility was higher in diets with XAP or phytase individually compared with NC. Both phytase and XAP individually and in combination improved ileal P digestibility compared with NC. 5. Total tract nutrient retention and ME increased as the birds grew older. There were age x diet interactions in total tract retention of P and Ca; improvement in P retention due to phytase use decreased by 50% as the chicks matured. 6. The current study shows that a combination of XAP and phytase improved performance, but the enhancement in performance appears to be due mainly to phytase. Both XAP and phytase were effective in improving P digestibility and retention of chicks receiving nutritionally marginal maize-soybean meal. 7. The data also showed that the chicks benefited more from the enzyme addition at a younger age and that the contribution of the enzymes to nutrient retention decreased with age in chickens.

Effect of change in symptoms, respiratory status, nutritional profile and quality of life on response to treatment for advanced non-small cell lung cancer

INTRODUCTION

Quality of life (QOL), and pulmonary and nutritional parameters are important outcome measures during treatment of lung cancer; however, the effect of chemotherapy on these factors and their relationship with clinical response is unclear.

METHODS

Patients with non-small cell lung cancer (NSCLC) were evaluated for symptom profile, nutritional status (using anthropometry), pulmonary functions by spirometry and six minute walk distance (6 MWD), and QOL using the WHO-QOL Bref 26 questionnaire, before and after chemotherapy.

RESULTS

Forty-four patients were studied (mean (SD) age, 55 (10) years, 75% males). The majority (98%) had stage III or IV disease and 72% were current / ex-smokers with median pack-years of 27.0 (range, 0.5-90). Some 61% had a Karnofsky Performance Scale (KPS) 70 or 80. The commonest symptoms were coughing, dyspnea, chest pain, anorexia and fever (79%, 72%, 68%, 57% and 40%, respectively). The mean (SD) 6 MWD was 322.5 (132.6) meters. The mean (SD) percentage forced vital capacity (FVC %), and forced expiratory volume in one second (FEV1 %) were 64.7 (18.8) and 57.8 (19.4), respectively. The mean (SD) QOL scores for the physical, psychological, social, and environmental domains were 52.9 (20.5), 56.1 (17.9), 64.5 (21.8), 57.1 (16.6), respectively. Fourteen patients (32%) responded to chemotherapy. Non-responders had significantly higher baseline occurrence of fever, anorexia, and weight loss, higher pack-years of smoking and poorer KPS compared to responders. Overall, chemotherapy caused significant decline in the frequency of coughing, dyspnea, chest pain, fever, anorexia, weight loss, and improvement in hemoglobin and albumin levels. There was no significant improvement in pulmonary functions, nutritional status, or QOL scores after treatment.

CONCLUSIONS

Lung cancer patients have a poor QOL. Although chemotherapy provides significant symptomatic benefit, this does not translate into similar benefit in respiratory and nutritional status or QOL. Patients with constitutional symptoms, higher smoking burden, and poor KPS are less likely to respond to chemotherapy. Management of NSCLC must include strategies to improve various aspects of QOL, nutritional status and pulmonary reserve to achieve comprehensive benefit.

Theoretical studies on photoelectron and IR spectral properties of Br2∙−(H2O)n clusters

We report vertical detachment energy (VDE) and IR spectra of Br2.-.(H2O)n clusters (n=1-8) based on first principles electronic structure calculations. Cluster structures and IR spectra are calculated at Becke's half-and-half hybrid exchange-correlation functional (BHHLYP) with a triple split valence basis function, 6-311++G(d,p). VDE for the hydrated clusters is calculated based on second order Moller-Plesset perturbation (MP2) theory with the same set of basis function. On full geometry optimization, it is observed that conformers having interwater hydrogen bonding among solvent water molecules are more stable than the structures having double or single hydrogen bonded structures between the anionic solute, Br2.-, and solvent water molecules. Moreover, a conformer having cyclic interwater hydrogen bonded network is predicted to be more stable for each size hydrated cluster. It is also noticed that up to four solvent H2O units can reside around the solute in a cyclic interwater hydrogen bonded network. The excess electron in these hydrated clusters is localized over the solute atoms. Weighted average VDE is calculated for each size (n) cluster based on statistical population of the conformers at 150 K. A linear relationship is obtained for VDE versus (n+3)(-1/3) and bulk VDE of Br2.- aqueous solution is calculated as 10.01 eV at MP2 level of theory. BHHLYP density functional is seen to make a systematic overestimation in VDE values by approximately 0.5 eV compared to MP2 data in all the hydrated clusters. It is observed that hydration increases VDE of bromine dimer anion system by approximately 6.4 eV. Calculated IR spectra show that the formation of Br2.--water clusters induces large shifts from the normal O-H stretching bands of isolated water keeping bending modes rather insensitive. Hydrated clusters, Br2.-.(H2O)n, show characteristic sharp features of O-H stretching bands of water in the small size clusters.

Structure, energy, and IR spectra of I2∙−.nH2O clusters (n=1–8): A theoretical study

The authors report theoretical results on structure, bonding, energy, and infrared spectra of iodine dimer radical anion hydrated clusters, I(2) (-).nH(2)O (n=1-8), based on a systematic study following density functional theory. Several initial guess structures are considered for each size cluster to locate minimum energy conformers with a Gaussian 6-311++G(d,p) split valence basis function (triple split valence 6-311 basis set is applied for iodine). It is observed that three different types of hydrogen bonded structures, namely, symmetrical double hydrogen bonding, single hydrogen bonding, and interwater hydrogen bonding structures, are possible in these hydrated clusters. But conformers having interwater hydrogen bonding arrangements are more stable compared to those of double or single hydrogen bonded structures. It is also noticed that up to four solvent H(2)O units can reside around the solute in interwater hydrogen bonding network. At the maximum six H(2)O units are independently linked to the dimer anion having four double hydrogen bonding and two single hydrogen bonding, suggesting the hydration number of I(2) (-) to be 6. However, conformers having H(2)O units independently linked to the iodine dimer anion are not the most stable structures. In all these hydrated clusters, the odd electron is found to be localized over two I atoms and the two atoms are bound by a three-electron hemi bond. The solvation, interaction, and vertical detachment energies are calculated for all I(2) (-).nH(2)O clusters. Energy of interaction and vertical detachment energy profiles show stepwise saturation, indicating geometrical shell closing in the hydrated clusters, but solvation energy profile fails to show such behavior. A linear correlation is observed between the calculated energy of interaction and vertical detachment energy. It is observed that formation of I(2) (-)-water cluster induces significant shifts from the normal O-H stretching modes of isolated H(2)O. However, bending mode of H(2)O remains insensitive to the successive addition of solvent H(2)O units. Weighted average energy profiles and IR spectra are reported for all the hydrated clusters based on the statistical population of individual conformers at room temperature.

Analgesic activity of Calotropis gigantea flower

The alcoholic extract of the flowers of Calotropis gigantea was administered orally and explored for its analgesic activity in chemical and thermal models in mice. In acetic acid induced writhing test, an inhibition of 20.97% and 43.0% in the number of writhes was observed at the doses of 250 and 500 mg/kg, respectively. In the hot plate method the paw licking time was delayed. The analgesic effect was observed after 30 min of dose administration which reached its maximum after 90 min.

Microhydration shell structure in Cl2∙−∙nH2O clusters: A theoretical study

We present the results of a detailed study on structure and electronic properties of hydrated cluster Cl2*-.nH2O (n = 1-7) based on a nonlocal density functional, namely, Becke's [J. Chem. Phys. 98, 1372 (1993)] half and half hybrid exchange-correlation functional with a split valence 6-311++G(d,p) basis function. Geometry optimizations for all the clusters are carried out with various possible initial guess structures without any symmetry restriction. Several minimum energy structures (conformers) are predicted with a small difference in total energy. There is a competition between the binding of solvent H2O units with Cl2*- dimer radical anion directly through ion-molecule interaction and forming interwater hydrogen-bonding network in Cl2*-.nH2O (n > or = 2) hydrated cluster. Structure having interwater H-bonded network is more stable over the structure where H2O units are connected to the solute dimer radical anion Cl2*- rather independently either by single or double H bonding in a particular size (n) of hydrated cluster Cl2*-.nH2O. At the maximum four solvent H2O units reside in interwater H-bonding network present in these hydrated clusters. It is observed that up to six H2O units are independently linked to the anion having four double H bondings and two single H bondings suggesting the primary hydration number of Cl2*- to be 6. In all these clusters, the odd electron is found to be mostly localized over the two Cl atoms and these two atoms are bound by a three-electron hemibond. Calculated interaction (between solute and different water clusters) and vertical detachment energy profiles show saturation at n = 6 in the hydrated cluster Cl2*-.nH2O (n = 1-7). However, calculated solvation energy increases with the increase in number of solvent H2O molecules in the cluster. Interaction energy varies linearly with vertical detachment energy for the hydrated clusters Cl2*-.nH2O (n < or = 6). Calculation of the vibration frequencies show that the formation of Cl2*(-)-water clusters induces significant shifts from the normal stretching modes of isolated water. A clear difference in the pattern of IR spectra is observed in the O-H stretching region of water from hexa- to heptahydrated cluster.

Quality of life in newly diagnosed patients with lung cancer in a developing country: is it important?

There are no data regarding quality of life (QoL) assessments in lung cancer in developing countries like India. Quality of life was evaluated in 76 newly diagnosed lung cancer patients by using the World Health Organization Quality of Life questionnaire in Hindi (WHOQoL-Bref) (men 87%). The mean age was 55 years (SD = 10). Cough, dyspnoea, chest pain and haemoptysis were present in 83%, 72%, 66% and 43% of patients respectively. The median duration of symptoms was 5.9 months (range 1-13). Eighty-nine per cent had non-small cell lung cancer. The median pack-years smoked was 23 (range 0.5-88). Most patients (53%) had a Karnofsky's Performance Status (KPS) of 70 and 83% had stage III or IV disease. Quality of life did not correlate with age, gender, presence or duration of symptoms, histological type, stage of disease or degree of smoking. The physical and psychological domains of QoL correlated significantly with the KPS (P = 0.001 and P = 0.01 respectively). Patients with a KPS of 80 had better physical (P < 0.001), psychological (P < 0.01) and social (P < 0.05) QoL than those with a KPS of 70. In conclusion, patients with lung cancer in a developing country like India have an unsatisfactory QoL. The Karnofsky's Performance Scale is a simple and reliable surrogate marker for assessing QoL in these patients. Larger multi-centric studies may help in providing a more comprehensive evaluation of the effect of various demographic and clinical variables on QoL in this setting.

A comparative ab initio study of Br2•− and Br2 water clusters

The work presents ab initio results on structure and electronic properties of Br2*-.nH2O(n=1-10) and Br2.nH2O(n=1-8) hydrated clusters to study the effects of an excess electron on the microhydration of the halide dimer. A nonlocal density functional, namely, Becke's half-and-half hybrid exchange-correlation functional is found to perform well on the present systems with a split valence 6-31++G(d,p) basis function. Geometry optimizations for all the clusters are carried out with several initial guess structures and without imposing any symmetry restriction. Br2*-.nH2O clusters prefer to have symmetrical double hydrogen-bonding structures. Results on Br2.nH2O(n>or=2) cluster show that the O atom of one H2O is oriented towards one Br atom and the H atom of another H2O is directed to other Br atom making Br2 to exist as Br+-Br- entity in the cluster. The binding and solvation energies are calculated for the Br2*-.nH2O and Br2.nH2O clusters. Calculations of the vibrational frequencies show that the formation of Br2*- and Br2 water clusters induces significant shifts from the normal modes of isolated water. Excited-state calculations are carried out on Br2*-.nH2O clusters following configuration interaction with single electron excitation procedure and UV-VIS absorption profiles are simulated. There is an excellent agreement between the present theoretical UV-VIS spectra of Br2*-.10H2O cluster and the reported transient optical spectra for Br2*- in aqueous solution.

Survival in small cell lung cancer in India: Prognostic utility of clinical features, laboratory parameters and response to treatment

BACKGROUND

Predictors of survival and response to treatment in patients with small cell lung cancer (SCLC) are ill-defined and unclear. In an attempt to assess the impact of common presenting symptoms and laboratory values on survival, we undertook this retrospective review of patients with SCLC. To our knowledge, there is no study on survival in SCLC patients from the Indian subcontinent.

DESIGN

Retrospective Cohort study.

MATERIALS AND METHODS

All newly diagnosed small cell lung cancer cases from December 2001 through December 2004, were identified and clinical data on presenting symptoms and laboratory findings from their hospital records, noted. The influence of various pretreatment factors on survival was investigated using Kaplan-Meier plots and Cox multivariate regression model.

RESULTS

76 subjects were included (84% males, 91% smokers). 57% patients had five or more symptoms at presentation. Cumulative symptom burden was strongly associated with survival (P =0.02). Survival was also significantly related with Karnofsky performance status (KPS) (P =0.04), disease extent (P =0.03) and symptomatic response to treatment (P< 0.001). Patients with higher hemoglobin (P =0.02), serum sodium (P =0.04) and serum globulin (P =0.02), survived significantly longer. By multivariate regression analysis, hemoglobin, KPS and brain metastases, were significant predictors of survival (P =0.01, P =0.02, P< 0.01 respectively).

CONCLUSION

Cumulative symptom burden, KPS, disease extent and symptomatic assessment of improvement after treatment, are useful predictors of survival. This has important clinical implications, keeping in view, the infrastructure and cost involved in more objective tests like CT scan, for evaluation of disease extent and prognosis. These findings can provide a simple basis for predicting prognosis in small cell lung cancer, especially in developing countries like ours.

Non small cell lung cancer (NSCLC): current status and future prospects

The incidence of lung cancer is rising dramatically and it is now the commonest cause of mortality and morbidity not only in the industrialised countries, but in developing nations like India as well. Tobacco smoking has consistently been demonstrated to be an important aetiological factor, though lung cancer occurs in non-smokers also. In spite of great advances in radiological and molecular diagnostic techniques, the ideal screening marker for early detection of lung cancer has still not been found. Histological diagnosis and staging is essential for selecting the mode of therapy in patients with lung cancer. Stages I and II are amenable to surgery. However, advanced stage III and IV need an individualised combination of surgery, chemotherapy and radiotherapy. With a better understanding of the cellular mechanisms operating in carcinogenesis, newer target specific modalities are being developed and tested in order to stem this disease, which threatens to assume epidemic proportions.

Studies on (beta,1-->5) and (beta,1-->6) linked octyl Gal(f) disaccharides as substrates for mycobacterial galactosyltransferase activity

The emergence of multi-drug resistant (MDR) strains of Mycobacterium tuberculosis (MTB) and the continuing pandemic of tuberculosis emphasizes the urgent need for the development of new anti-tubercular agents with novel drug targets. The recent structural elucidation of the mycobacterial cell wall highlights a large variety of structurally unique components that may be a basis for new drug development. This publication describes the synthesis, characterization, and screening of several octyl Galf(beta,1-->5)Galf and octyl Galf(beta,1-->6)Galf derivatives. A cell-free assay system has been utilized for galactosyltransferase activity using UDP[14C]Galf as the glycosyl donor, and in vitro inhibitory activity has been determined in a colorimetric broth microdilution assay system against MTB H37Ra and three clinical isolates of Mycobacterium avium complex (MAC). Certain derivatives showed moderate activities against MTB and MAC. The biological evaluation of these disaccharides suggests that more hydrophobic analogues with a blocked reducing end showed better activity as compared to totally deprotected disaccharides that more closely resemble the natural substrates in cell wall biosynthesis.

Studies on alpha(1-->5) linked octyl arabinofuranosyl disaccharides for mycobacterial arabinosyl transferase activity

The appearance multi-drug resistant Mycobacterium tuberculosis (MTB) throughout the world has prompted a search for new, safer and more active agents against tuberculosis. Based on studies of the biosynthesis of mycobacterial cell wall polysaccharides, octyl 5-O-(alpha-D-arabinofuranosyl)-alpha-D-arabinofuranoside analogues were synthesized and evaluated as inhibitors for M. tuberculosis and Mycobacterium avium. A cell free assay system has been used for the evaluation of these disaccharides as substrates for mycobacterial arabinosyltransferase activity.

Synthesis of disaccharides related to the mycobacterial arabinogalactan

Several novel glycofuranoses disaccharides related to mycobacterial cell wall polysaccharides were synthesized regio- and stereoselectively using 2,3,5-tri-O-benzoyl-alpha-D-arabinofuranosyl trichloroacetimidate as a glycosyl donor.

Carcinoma of the gallbladder: a retrospective review of 99 cases

Since the first description of the carcinoma of the gallbladder, about two centuries ago, this disease has evaded all attempts at early detection and a potential cure. There are only a few studies involving the Indian population, which has a high incidence of gallbladder cancer. Indians are ethnically and culturally different from their Western counterparts, for whom the incidence of this disease is comparatively low. The present study was conducted prospectively on 99 consecutive cases of carcinoma of the gallbladder of 736 patients with biliary diseases admitted to one surgical unit at the University Hospital. The staging, histological type, and grade were correlated with the clinical outcome. Abdominal pain (82.8%) and abdominal mass (73.7%) were the main presenting features. The diagnosis was obtained by ultrasonography (USG) in 93 of 99 cases and confirmed by fine-needle aspiration cytology (FNAC) in 70 patients. Ultrasonography, however, was found to be inadequate for accurate staging of the disease. Based on the TNM classification, 3 (3.0%), 12 (12.1%), 14 (14.1%), 12 (12.1%), and 58 (58.6%) patients had stage 0, I, II, III, and IV disease, with a corresponding mean survival of 28.3, 13.8, 7.5, 5.2, and 3.7 months, respectively. Carcinoma of the gallbladder is difficult to diagnose early due to its vague symptomatology. A high index of suspicion and health education seem to be the only answers available for early detection and improvement of survival.

Altered immunomodulating and toxicological properties of degraded Quillaja saponaria Molina saponins

Quillaja saponins are readily hydrolyzed under physiological conditions, yielding deacylated forms that are significantly less toxic than their precursors. Yet, deacylated saponins are unable to stimulate a strong primary immune response. Although deacylated saponins elicit a strong total IgG response, their capacity to stimulate a Thl type IgG isotype profile (i.e. high levels of IgG2a and IgG2b) has been significantly diminished. Instead, an IgG profile closer to that of a Th2 immune response is stimulated (i.e. high IgG1 levels). Deacylated saponins have also lost their capacity to elicit an effective T cell immunity, as shown by their stimulation of a marginal lymphoproliferative response and their inability to elicit the production of cytotoxic lymphocytes (CTL). Modification of the immune-modulating properties brought by the degradation of quillaja saponins during vaccine storage may change the intended immune response from a Th1 to a Th2 type. This alteration would have negligible effects on vaccines depending on Th2 immunity mediated by neutralizing antibodies. However, the performance of vaccines directed against intracellular pathogens as well as therapeutic cancer vaccines may be seriously affected by the loss of their capacity to stimulate both a Th1 immune response and the production of CTL.

Development of semisynthetic triterpenoid saponin derivatives with immune stimulating activity

Aldehyde-containing triterpene saponins have adjuvant properties, but only those from Quillaja saponaria Molina stimulate the production of cytotoxic T lymphocytes (CTL) against exogenous antigens. Quillaja saponins have two normonoterpene ester moieties, linked linearly to their fucosyl residue, that play a critical role in the stimulation of CTL. These ester moieties are also responsible for these saponins' instability and toxicity. Based on the structure-activity relationships for the different groups of Q. saponaria saponins, new semi-synthetic analogs were developed that have the adjuvanticity of quillaja saponins, yet with less toxicity and greater stability in aqueous solutions. The quillaja saponin analogs were prepared by replacing their hydrolytically unstable ester groups with another lipophilic chain linked by a stable amide bond on these saponins' glucuronic acid residue. One of these analogs, GPI-0100, is a dodecylamide saponin derivative that stimulates an antibody isotype profile that corresponds to a Th1 type immune response, as well as CTL production against exogenous antigens.

Possible involvement of cholinergic and adrenergic mechanisms in changing contractility of guinea pig ileum by Ipomoea carnea

The study aimed to elucidate the mechanism (s) of action of Ipomoea carnea leaf juice (ILJ) in changing contractility of guinea pig ileum. ILJ produced dose-dependent (10-10000 microg/ml) triphasic responses. The initial contractile phase was blocked by atropine (1 microg/ml) but had additive effect with acetylcholine (2 ng/ml) or carbachol (2 ng/ml). Neostigmine (30 ng/ml) or lignocaine (50 microg/ml) failed to alter the response. In cold-induced denervated preparations, this phase was augmented. The relaxatory phase of ILJ was not modified by phenoxybenzamine (35 microg/ml) but was reduced by propranolol (1 microg/ml) and abolished by lignocaine (50 microg/ml). The final contractile phase of ILJ was not affected by atropine (1 microg/ml). These results suggest that the triphasic response of ILJ is possibly mediated through cholinergic, adrenergic and non-cholinergic mechanisms, respectively.

Studies on beta-D-Gal(f)-(1-->4)-alpha-L-Rha(p) octyl analogues as substrates for mycobacterial galactosyl transferase activity

The biochemically unique structures of sugar residues in the outer cell wall of Mycobacterium tuberculosis (MTB) make the pathways for their biosynthesis and utilization attractive targets for the development of new and selective anti-tubercular agents. A cell-free assay system for galactosyltransferase activity using UDP[14C]Gal as the glycosyl donor, as well as an in vitro colorimetric broth micro-dilution assay system, were used to determine the activities of three beta-D-gal(f)(1-->4)-alpha-L-rham(p) octyl disaccharides as substrates and antimycobacterial agents respectively. The cell-free enzymatic studies using compounds 8 and 10 suggested that these disaccharides bind to and are effective substrates for a putative mycobacterial galactosyltransferase. The modified acceptor 8 was found to be a slower but prolonged binder as compared to the less substituted analogue 10 as evidenced by their Km and Vmax values. Moderate antimycobacterial activity was observed with compounds 8 and 9 against MTB H37Ra and three clinical isolates of Mycobacterium avium complex (MAC).