Ab initioinvestigation of the lattice dynamics and thermophysical properties of BCC vanadium and niobium

In the present work, we have performed the phonon dispersion calculations of body-centered cubic vanadium (V) and niobium (Nb) with the supercell approach using different supercell size. Using DFT method, the calculated phonon spectra of V and Nb are found to be in a good agreement with the available experimental data. Our calculated results show a 'dip'-like feature in the longitudinal acoustic phonon mode along the Γ-H high symmetric path for both transition metals in the case of supercell size4×4×4. However, in supercell size2×2×2and3×3×3, the 'dip'-like feature is not clearly visible. In addition to this, thermodynamical properties are also computed, which compare well with the experimental data. Apart from this, the phonon lifetime due to electron-phonon interactions (τephph) and phonon-phonon interactions (PPIs) (τphph) are calculated. The effect of PPIs is studied by computing the average phonon lifetime for all acoustic branches. The value ofτephphof V (Nb) is found to be 23.16 (24.70)×10-15s at 100 K, which gets decreased to 1.51 (1.85)×10-15s at 1000 K. Theτphphof V (Nb) is found to be 8.59 (18.09)×10-12and 0.83 (1.76)×10-12s at 100 and 1000 K, respectively. Nextly, the lattice thermal conductivity is computed using linearized phonon Boltzmann equation. The present work suggests that studying the variation of phonon dispersion with supercell size is crucial for understanding the phonon properties of solids accurately.

Existence of nodal-arc and its evolution into Weyl-nodes in the presence of spin-orbit coupling in TaAs & TaP

In this work, we report the existence ofnodal-arc, which acts as the building block of all the nodal-rings in TaAs & TaP. Thisnodal-arcis found to be capable of generating all the nodal-rings in these materials upon the application of space-group symmetry operations including time-reversal symmetry. The arcs are obtained to be dispersive with the energy spread of ∼109 (∼204) meV in TaAs (TaP). Also, the orbitals leading to bands-inversion and thus the formation ofnodal-arcsare found to be Ta-5d& As-4p(P-3p) in TaAs (TaP). The area of nodal-rings is found to be highly sensitive to the change in hybridization-strength, where the increase in hybridization-strength leads to the decrease in the area of nodal-rings. In the presence of spin-orbit coupling (SOC), all the points on these arcs get gaped-up and two pairs of Weyl-nodes are found to evolve from them. Out of the two pair, one is found to be situated close to the joining point of the two arcs forming a ring. This causes the evolution of each nodal-ring into three pairs of Weyl-nodes. The coordinates of these Weyl-nodes are found to be robust to the increase in SOC-strength from ∼0.7-3.5 eV. All the results are obtained at thefirst-principlelevel. This work provides a clear picture of the existence ofnodal-arcdue to accidental degeneracy and its evolution into Weyl-nodes under the effect of SOC.

Evidence of charge susceptibility and multiplef-chybridization configurations with the La doping in CeGe: a DFT + DMFT study

Kondo coupling has been extensively investigated in several Ce-based systems. However, the search for materials showing the interplay between the Kondo effect, spin-orbit interaction, and crystal-field effect along with the presence of local charge susceptibility; remains a challenge for the condensed matter community. Actually, in Ce-based systems, the strong coupling of the conduction electrons to the local magnetic moments usually hides these properties. Here, we present a detailed investigation of Ce_0.6La_0.4Ge through a combined density functional theory and dynamic mean-field theory study. Our investigations give evidence of the significant charge susceptibility and the multiple differentf-chybridization configurations. The weakening of the magnetization owing to the dilution of the Ce-site is the main cause for the appearance of such properties, which is believed to occur due to the presence of the relevant local moment andf-chybridization over the competition with the on-site Coulomb interaction.

Does Liposuction for Lymphedema Worsen Lymphatic Injury?

Liposuction for treatment of lymphedema is an effective and time-tested treatment. However, as there is a fear regarding further lymphatic damage caused by liposuction, we objectively compared lymphatic function pre- and post-liposuction. All patients with solid-predominant lymphedema who were treated during the study period of June 2014 and November 2018 were included. Patients were assessed using patient-reported baselines/outcomes, lymphedema- specific quality of life scale (LYMQOL), limb circumference/volume measurements, and indocyanine green lymphography (ICGL) preoperatively and at predefined postoperative time intervals. Fifty-seven limbs from 41 patients were included. Mean lipoaspirate volumes were 2035 mL, 5385 mL, and 3106 mL for the arm, thigh, and leg, respectively with a mean adipose fraction of the lipoaspirate of 71%. All patients underwent redundant skin excision with the "flying squirrel" technique. The mean follow-up was 10.7 months (range 3 - 48 months) with a mean limb volume reduction of 32.2% and all patients reporting satisfactory relief of symptoms. All showed statistically significant improvement in LYMQOL in symptoms, appearance, and function. On ICGL, none showed worsened lymphatic drainage, rather, all showed improved lymph drainage. Furthermore, the improved lymph drainage was found to be progressive during the study period in all patients. Our study results demonstrate that treating extremity lymphedema with liposuction does not worsen lymphatic function and in fact, paradoxically, it induces progressive improvement in lymph drainage.

Possible realization of three-dimensional quantum spin liquid behavior in HoVO4

The study of geometrically frustrated magnetic systems with unusual crystal field ground states offers a possibility of realizing the new aspects of physics of disordered systems. In this study, we report our results of structural, magnetic susceptibility, heat capacity measurements, along with density functional theory (DFT) calculations on HoVO₄; a compound in which the presence of a distorted kind of HoO₈polyhedral leads to multiple magnetic interaction paths. The observed broad maximum below 10 K in the temperature response of DC susceptibility curves implies the presence of short-range correlations. AC susceptibility rules out the possibility of any kind of spin freezing. Temperature dependent heat capacity measurement at zero field indicate towards the absence of long-range ordering, along with the presence of a broad maximum centered around 14 K. The residual heat capacity exhibits a characteristic power-law (T^α) behavior with the exponentαnearly equal to 2, which is analogous to that observed for other three-dimensional (3D) quantum spin liquid (QSL) systems. The DFT calculations signify the presence of dominant second and third nearest neighbor interactions, which in turn lead to magnetic frustration in our system. Our investigations suggest that HoVO₄can be a candidate for realizing a 3D QSL state.

Evidence of phase stability, topological phonon and temperature-induced topological phase transition in rocksalt SnS and SnSe

Both SnS and SnSe have been experimentally and theoretically confirmed as topological crystalline insulators in native rocksalt structure. Here, phononic structure, thermodynamic properties and temperature dependent electron-phonon interaction (EPI) have investigated for both the materials in rocksalt phase. Previously performed theoretical studies have predicted the phase instability of SnS in this crystal structure at ambient condition. But, after a detailed study performing on the phonon calculation of SnS, we have predicted the phase stability of SnS with considering the Sn 4porbitals as valence states inab-initiocalculation. The importance of long range Coulomb forces along with the themodynamical properties are also described in detailed for both materials. The computed value of Debye temperature (ΘD) for SnS (SnSe) is ∼315.0 K (∼201.7 K). The preliminary evidence of topological phonon is found alongX-Wdirection, where the linear band touching is observed as compared to type II Weyl phononic material ZnSe (Liuet al2021Phys. Rev.B103094306). The topological phase transition is seen for these materials due to EPI, where non-linear temperature dependent bandgap is estimated. The predicted value of transition temperature for SnS (SnSe) is found to be ∼700 K, where after this temperature the non-trivial to trivial topological phase is seen. The strength of EPI shows more stronger impact on the electronic structure of SnS than SnSe material. The reason of non-linear behaviour of bandgap with rise in temperature is discussed with the help of temperature dependent linewidths and lineshifts of conduction band and valence band due to EPI. The present study reveals the phase stability of SnS along with the comparative study of thermal effect on EPI of SnS and SnSe. Further, the possibility of temperature induced topological phase transition provides one of important behaviour to apply these two materials for device making application.

Experimental and computational approaches to study the high temperature thermoelectric properties of novel topological semimetal CoSi

Here, we study the thermoelectric properties of topological semimetal CoSi in the temperature range 300-800 K by using combined experimental and density functional theory (DFT) based methods. CoSi is synthesized using arc melting technique and the Rietveld refinement gives the lattice parameters ofa=b=c= 4.445 Å. The measured values of Seebeck coefficient (S) shows the non-monotonic behaviour in the studied temperature range with the value of ∼-81μV K^-1at room temperature. The |S| first increases till 560 K (∼-93μV K^-1) and then decreases up to 800 K (∼-84μV K^-1) indicating the dominating n-type behaviour in the full temperature range. The electrical conductivity,σ(thermal conductivity,κ) shows the monotonic decreasing (increasing) behaviour with the values of∼5.2×105(12.1 W m^-1 K^-1) and∼3.6×105(14.2 W m^-1 K^-1) Ω^-1 m^-1at 300 K and 800 K, respectively. Theκexhibits the temperature dependency as,κ∝T^0.16. The DFT based Boltzmann transport theory is used to understand these behaviour. The multi-band electron and hole pockets appear to be mainly responsible for deciding the temperature dependent transport behaviour. Specifically, the decrease in the |S| above 560 K and change in the slope ofσaround 450 K are due to the contribution of thermally generated charge carriers from the hole pockets. The temperature dependent relaxation time (τ) is computed by comparing the experimentalσwith calculatedσ/τand it shows temperature dependency of 1/T^0.35. Further this value ofτis used to calculate the temperature dependent electronic part of thermal conductivity (κ_e) and it gives a fairly good match with the experiment. Present study suggests that electronic band-structure obtained from DFT provides a reasonably good estimate of the transport coefficients of CoSi in the high temperature region of 300-800 K.

Exploring temperature dependent electron-electron interaction of rocksalt SnS and SnSe within Matsubara-time domain

Both experimental and theoretical studies show non-trivial topological behaviour in native rocksalt phase for SnS and SnSe and categorize these materials in topological crystalline insulators. Here, the detailed electronic structures studies of SnS and SnSe in the rocksalt phase are carried out using many-bodyGWbased theory and density functional theory both for ground states and temperature dependent excited states. The estimated values of fundamental direct bandgaps aroundL-point usingG₀W₀(mBJ) are ∼0.27 (∼0.13) eV and ∼0.37 (∼0.17) eV for SnS and SnSe, respectively. The strength of hybridization between Sn 5pand S 3p(Se 4p) orbitals for SnS (SnSe) shows strongk-dependence. The behaviour ofW¯(ω), which is the averaged value of diagonal matrix elements of fully screened Coulomb interaction, suggests to use full-GWmethod for exploring the excited states because the correlation effects within these two materials are relatively weak. The temperature dependent electronic structure calculations for SnS and SnSe provide linearly decreasing behaviour of bandgaps with rise in temperatures. The existence of collective excitation of quasiparticles in form of plasmon is predicted for these compounds, where the estimated values of plasmon frequency are ∼9.5 eV and ∼9.3 eV for SnS and SnSe, respectively. The imaginary part of self-energy and mass renormalization factor (Z_k(ω)) due to electron-electron interaction (EEI) are also calculated alongW-L-Γ direction for both the materials, where the estimated ranges ofZ_k(ω) are 0.70 to 0.79 and 0.71 to 0.78 for SnS and SnSe, respectively, along thisk-direction. The present comparative study reveals that the behaviour of temperature dependent EEI for SnS and SnSe are the almost same and EEI is important for high temperature transport properties.

Instrument for simultaneous measurement of Seebeck coefficient and thermal conductivity in the temperature range 300-800 K with Python interfacing

Fabrication and characterization of an instrument for the high-temperature simultaneous measurement of the Seebeck coefficient (S) and thermal conductivity (κ) have been carried out with Python automation. The steady-state-based Fourier's law of thermal conduction is employed for κ measurement. The parallel thermal conductance technique is implemented for heat loss measurement. Introducing a thin heater and insulating heater base minimizes the heat loss and makes it easier to arrive at high temperatures. Measurement of S is carried out using the differential method. The same thermocouples are used to measure the temperature as well as voltage for S measurement. Care of temperature dependent S of the thermocouple has also been taken. Simple design, small size, and lightweight make this instrument more robust. All the components for making a sample holder are easily available in the market and can be replaced as per the user's demand. This instrument can measure samples with various dimensions and shapes in the temperature range 300-800 K. The instrument is validated using different classes of samples, such as nickel, gadolinium, Fe₂VAl, and LaCoO₃. A wide range of S values from ∼-20 to ∼600 μV/K and κ values from ∼1.1 to ∼23.5 W/m K are studied. The measured values of S and κ are in good agreement with the reported data.

Understanding the Seebeck coefficient of LaNiO3compound in the temperature range 300-620 K

Transition metal oxides have been attracted much attention in thermoelectric community from the last few decades. In the present work, we have synthesized LaNiO₃by a simple solution combustion process. To analyse the crystal structure and structural parameters we have used Rietveld refinement method wherein FullProf software is employed. The room temperature x-ray diffraction indicates the rhombohedral structure with space groupR3¯c(No. 167). The refined values of lattice parameters area=b=c= 5.4071 Å. Temperature dependent Seebeck coefficient (S) of this compound has been investigated by using experimental and computational tools. The measurement ofSis conducted in the temperature range 300-620 K. The measured values ofSin the entire temperature range have negative sign that indicates n-type character of the compound. The value ofSis found to be ∼-8μV/K at 300 K and at 620 K this value is ∼-12μV/K. The electronic structure calculation is carried out using DFT +Umethod due to having strong correlation in LaNiO₃. The calculation predicts the metallic ground state of the compound. Temperature dependentSis calculated using BoltzTraP package and compared with experiment. The best matching between experimental and calculated values ofSis observed when self-interaction correction is employed as double counting correction in spin-polarized DFT +U(=1 eV) calculation. Based on the computational results maximum power factors are also calculated for p-type and n-type doping of this compound.

Anab initiostudy of topological and transport properties of YAuPb

In the last few decades, the study of topological materials has been carried out on an extensive scale. Half-Heusler alloys are well known for their topological behaviours. In this work, we present a detailed study of topological properties of a ternary half-Heusler alloy, YAuPb, using the tight-binding approach. We have calculated some important topological properties which includes-finding nodes and their chiralities, Berry curvature (Ω) and the surface-states. Five pairs of characteristic nodes with equal and opposite chiralities are obtained. Based on the study of these properties, we categorise the material as non-trivial topological semimetal. Besides the topological behaviours, we present a comparative study of temperature dependent transport properties corresponding to the chemical potential (μ) of the Fermi level and the node points. The temperature range chosen for the study is 50-300 K. The results obtained from the calculations of electrical conductivity per unit relaxation time (σ/τ) and the electronic part of thermal conductivity per unit relaxation time (κ₀) indicates the conducting nature of the material to both the heat and electricity. At the Fermi level, the value of Seebeck coefficient (S) is found to be ∼-9.07(-35.95) μV K^-1at 50(300) K. The negative value ofSindicates the n-type behaviour of the compound. The calculated value of electronic specific heat (Pauli magnetic susceptibility) corresponding to Fermi level is ∼0.03(0.18) × 10^-2 J mol^-1 K^-1(∼1.21(1.14) × 10^-10 m³ mol^-1) at 50(300) K. This work suggests that YAuPb is a promising candidate of non-trivial topological semimetals which can be employed in transmission of heat and electricity, and as n-type material within the temperature range of 50-300 K.

Studying the lifetime of charge and heat carriers due to intrinsic scattering mechanisms in FeVSb half-Heusler thermoelectric

This work, presents a study of lifetime of carriers due to intrinsic scattering mechanisms viz. electron-electron interaction (EEI), electron-phonon interaction (EPI) and phonon-phonon interaction (PPI) in a promising half-Heusler thermoelectric FeVSb. Using the full-GWmethod, the effect of EEI and temperature on the valence and conduction band extrema and band gap are studied. The lifetime of carriers with temperature are estimated at these band extrema. At 300 K, estimated value of lifetime at VBM (CBM) is ∼1.91 × 10^-14 s (∼2.05 × 10^-14 s). The estimated ground state band gap considering EEI is ∼378 meV. Next, the effect of EPI on the lifetime of electrons and phonons with temperature are discussed. The comparison of two electron lifetimes suggests that EEI should be considered in transport calculations along with EPI. The average acoustic, optical and overall phonon lifetimes due to EPI are studied with temperature. Further, the effect of PPI is studied by computing average phonon lifetime for acoustic and optical phonon branches. The lifetime of the acoustic phonons are higher compared to optical phonons which indicates acoustic phonons contribute more to lattice thermal conductivity (κ_ph). The comparison of phonon lifetime due to EPI and PPI suggests that, above 500 K EPI is the dominant phonon scattering mechanism and cannot be ignored inκ_phcalculations. Lastly, a prediction of the power factor and figure of merit of n-type and p-type FeVSb is made by considering the temperature dependent carrier lifetime for the electronic transport terms. This study shows the importance of considering EEI in electronic transport calculations and EPI in phonon transport calculations in FeVSb. Our study is expected to provide results to further explore the thermoelectric transport in this material.

Investigating the effect of temperature dependent many-body interactions on electronic structures of SnTe in the Matsubara-time domain

Recently, SnTe has gained attention due to its non-trivial topological nature and eco-friendly thermoelectric applications. We report a detailed temperature dependent electronic structure of this compound using DFT andGWmethods. The calculated values of bandgaps by using PBEsol andG₀W₀methods are found to be in good agreement with the experiment, whereas mBJ underestimates the bandgap. The averaged value of diagonal matrix elements of fully screened Coulomb interaction (W̄) atω= 0 eV for Sn (Te) 5porbitals is ∼1.39 (∼1.70) eV. The nature of frequency dependentW̄(ω)reveals that the correlation strength of this compound is relatively weaker and hence the excited electronic state can be properly studied by full-GWmany-body technique. The plasmon excitation is found to be important in understanding this frequency dependentW̄(ω). The temperature dependent electron-electron interactions (EEI) reduces the bandgaps with increasing temperature. The value of bandgap at 300 K is obtained to be ∼161 meV. The temperature dependent lifetimes of electronic state alongW-L-Γ direction are also estimated. This work suggests that EEI is important to explain the high temperature transport behaviour of SnTe.

Early detection of Pseudomonas aeruginosa and Escherichia coli. using zinc tetraphenylporphyrin

The sensory characteristics of food are considerably effected by the metabolic processes of various micro-organisms in the food stored in the field or at ambient temperature. Also, this microbial contamination can pose serious health hazards to public health. Chemical analysis of the complex mixture of volatiles produced during bacterial growth and investigation methods of these microorganisms presents a big challenge. There remains major unmet need to shorten and improve detection methods. Therefore, early detection of the microorganisms will open many frontiers for quality control in the foodstuffs industry. Accordingly, the aim of this study was to assess the feasibility and performance of chemoreceptive sensors for the rapid detection of bacterial pathogens, specifically Pseudomonas aeruginosa and Escherichia coli.

In Uv/vis study, zinc tetraphenyl porphyrin solutions (in DMF) was tested with various volatile compounds, such as propanal, hexanal and heptanal which are commonly found to be released during the growth of bacteria. These sensors were used to detect the bacterial odours of two pathogenic species (E.coli and P.aeruginosa) during their growth cycle at 4 °C and ambient temperature.

Hypochromic shifts in Uv/vis and hydrogen bonding in FT-IR studies confirmed the interaction between the volatiles and porphyrin. The porphyrin used detected the presence of microorganisms after 12 hrs incubation and showed more sensitivity for volatiles released during aerobic activity P. aeruginosa as compared to E. coli at 4 °C and ambient temperature.

Zinc tetraphenyl porphyrin based chemoreceptive membranes has been proved successful for the detection of P. aeruginosa. Hence, the present study proves wide scope of improvement over current laboratory techniques for the detection of pathogens in terms of speed, ease of use, and cost.

Key messages

The developed technique allows rapid detection of spoiled food. Chemoreceptive property of porphyrin has been exploited for the early detection of bacteria.

Probing the Electronic Structure of Hybrid Perovskites in the Orientationally Disordered Cubic Phase

Hybrid organic-inorganic lead halide perovskites are projected as new generation photovoltaic and optoelectronic materials with improved efficiencies. However, their electronic structure so far remains poorly understood, particularly in the orientationally disordered cubic phase. We performed electronic structure investigations using angle-resolved photoemission spectroscopy on two prototypical samples (MAPbBr₃ and MAPbCl₃) in their cubic phase, and the results are compared with the calculations within two theoretical models where MA⁺ is orientationally (1) disordered (MA⁺ ion is replaced by spherically symmetric Cs⁺ ion) and (2) ordered (MA oriented along (100) direction) but keeping the symmetry of the unit cell cubic. Degeneracy of the valence bands and behavior of constant energy contours are consistent with model 1, which supports strongly the disordered nature of the orientation of the MA⁺ ions in the cubic phase. Band structure calculations also reveal that spin-orbit coupling induced Rashba splitting is suppressed by the orientational disorder.

Thermoelectric properties, efficiency and thermal expansion of ZrNiSn half-Heusler by first-principles calculations

In this work, we try to understand the experimental thermoelectric (TE) properties of a ZrNiSn sample with DFT and semiclassical transport calculations using SCAN functional. SCAN and mBJ provide the same band gapEgof ∼0.54 eV. ThisEgis found to be inadequate to explain the experimental data. The better explanation of experimental Seebeck coefficientSis done by consideringEgof 0.18 eV which suggests the non-stoichiometry and/or disorder in the sample. In the calculation ofSand other TE properties temperature dependence on chemical potential is included. In order to look for the possible enhanced TE properties obtainable in ZrNiSn withEgof ∼0.54 eV, power factor and optimal carrier concentrations are calculated. The optimal electron and hole concentrations required to attain highest power factors are ∼7.6 × 1019cm-3and ∼1.5 × 1021cm-3, respectively. The maximum figure of meritZTcalculated at 1200 K for n-type and p-type ZrNiSn are ∼0.5 and ∼0.6, respectively. The % efficiency obtained for n-type ZrNiSn is ∼4.2% while for p-type ZrNiSn is ∼5.1%. TheZTare expected to be further enhanced to ∼1.1 (n-type) and ∼1.2 (p-type) at 1200 K by doping with heavy elements for thermal conductivity reduction. The phonon properties are also studied by calculating dispersion, total and partial density of states. The calculated Debye temperature of 382 K is in good agreement with experimental value of 398 K. The thermal expansion behaviour in ZrNiSn is studied under quasi-harmonic approximation. The average linear thermal expansion coefficientαave(T) of ∼7.8 × 10-6K-1calculated in our work is quite close to the experimental values. The calculated linear thermal expansion coefficient will be useful in designing the thermoelectric generators for high temperature applications.

First-principles electronic structure, phonon properties, lattice thermal conductivity and prediction of figure of merit of FeVSb half-Heusler

In this work, we have studied the electronic structure of a promising thermoelectric half-Heusler FeVSb using FP-LAPW method and SCAN meta-GGA including spin-orbit coupling. Using the obtained electronic structure and transport calculations we try to address the experimental Seebeck coefficient S of FeVSb samples. The good agreement between the experimental and calculated S suggests the band gap could be ∼0.7 eV. This is supported by the obtained mBJ band gap of ∼0.7 eV. Further, we study and report the phonon dispersion, density of states and thermodynamic properties. The effect of long range Coulomb interactions on phonon frequencies are also included by nonanalytical term correction. Under quasi-harmonic approximation, the thermal expansion behaviour up to 1200 K is calculated. Using the first-principles anharmonic phonon calculations, the lattice thermal conductivity κ _ph of FeVSb is obtained under single-mode relaxation time approximation considering the phonon-phonon interaction. At 300 K, the calculated κ _ph is ∼18.6 W m^-1 K^-1 which is higher compared to experimental value. But, above 500 K the calculated κ _ph is in good agreement with experiment. A prediction of figure of merit ZT and efficiency for p-type and n-type FeVSb is made by finding out optimal carrier concentration. At 1200 K, a maximum ZT of ∼0.66 and ∼0.44 is expected for p-type and n-type FeVSb, respectively. For p-type and n-type materials, maximum efficiency of ∼12.2% and ∼6.0% are estimated for hot and cold temperature of 1200 K and 300 K, respectively. A possibility of achieving n-type and p-type FeVSb by elemental doping/vacancy is also discussed. Our study is expected to help in further exploring the thermoelectric material FeVSb.

Two functionals approach in DFT for the prediction of thermoelectric properties of Fe2ScX (X = P, As, Sb) full-Heusler compounds

In the quest for new thermoelectric materials with high power factors, full-Heusler compounds having flat band are found to be promising candidates. In this direction, Fe₂ScX (X  =  P,As,Sb) compounds are investigated using mBJ for the band gap and SCAN to describe the electronic bands and phonon properties for thermoelectric applications. The band gaps obtained from mBJ are 0.81 eV, 0.69 eV and 0.60 eV for Fe₂ScX compounds. The phonon dispersion, phonon density of states (DOS) and partial DOS are calculated. The phonon contributions to specific heat are obtained as a function of temperature under harmonic approximation. The electronic band structutre calculated from mBJ and SCAN functionals are qualitatively compared. The effective mass values are calculated at the band extrema from SCAN functional. The thermoelectric parameters are calculated for both hole and electron dopings under semiclassical theory. We use a simple, but reasonable method to estimate the phonon relaxation time ([Formula: see text]). Using the specific heat, estimated [Formula: see text] and slopes (phase velocity) of acoustic branches in the linear region, lattice thermal conductivity ([Formula: see text]) at 300 K is calculated for three compounds. The obtained values of [Formula: see text] with constant [Formula: see text] are 18.2, 13.6 and 10.3 Wm^-1 K^-1, respectively. Finally, the temperature dependent figure of merit ZT values are calculated for optimal carrier concentrations in the doping range considered, to evaluate the materials for thermoelectric application. The ZT values for n-type Fe₂ScX, in 900-1200 K, are 0.34-0.43, 0.40-0.48 and 0.45-0.52, respectively. While, the p-type Fe₂ScX have ZT values of 0.25-0.34, 0.20-0.28 and 0.18-0.26, respectively in the same temperature range. The ZT values suggest that, Fe₂ScX compounds can be promising materials in high temperature power generation application on successful synthesis and further [Formula: see text] reduction by methods like nanostructuring.

The Interpeduncular Angle: A Practical and Objective Marker for the Detection and Diagnosis of Intracranial Hypotension on Brain MRI

BACKGROUND AND PURPOSE

Classic findings of intracranial hypotension on MR imaging, such as brain stem slumping, can be variably present and, at times, subjective, potentially making the diagnosis difficult. We hypothesize that the angle between the cerebral peduncles correlates with the volume of interpeduncular cistern fluid and is decreased in cases of intracranial hypotension. We aimed to investigate its use as an objective assessment for intracranial hypotension.

MATERIALS AND METHODS

Brain MRIs of 30 patients with intracranial hypotension and 30 age-matched controls were evaluated by 2 fellowship-trained neuroradiologists for classic findings of intracranial hypotension and the interpeduncular angle. Group analysis was performed with a Student t test, and receiver operating characteristic analysis was used to identify an ideal angle threshold to maximize sensitivity and specificity. Interobserver reliability was assessed for classic findings of intracranial hypotension using the Cohen κ value, and the interpeduncular angle, using the intraclass correlation.

RESULTS

The interpeduncular angle had excellent interobserver reliability (intraclass correlation coefficient value = 0.833) and was significantly lower in the intracranial hypotension group compared with the control group (25.3° versus 56.3°; P < .001). There was significant correlation between the interpeduncular angle and the presence of brain stem slumping (P < .001) and in cases with ≥3 classic features of intracranial hypotension (P = .01). With a threshold of 40.5°, sensitivity and specificity were 80% and 96.7%, respectively.

CONCLUSIONS

The interpeduncular angle is a sensitive and specific measure of intracranial hypotension and is a reliably reproducible parameter on routine clinical MR imaging.

Effects of correlations and temperature on the electronic structures and related physical properties of FeSi and CoSi: a comprehensive study

Here, we report detailed investigations of the temperature dependent (100-800 K) electronic structures of FeSi and CoSi by using a DFT+DMFT method where self-consistently calculated values of U and J are used. The calculated spectral functions are found to provide fairly good representation for the experimentally observed photoemission spectra for both the compounds. For FeSi, the density of states (DOS) closer to the Fermi level are found to increase with the increase in temperature up to 450 K and then they decrease, whereas, for CoSi DOS continuously decrease with an increase in temperature. The electronic states of FeSi are greatly influenced by electronic correlations while they are moderately influenced in CoSi. From momentum resolved spectral functions, the excitations have shown enhanced broadening with temperature rise in FeSi whereas an opposite behavior is observed in CoSi. In FeSi, the maximum effect of temperature on the lifetime of [Formula: see text] quasiparticles states is observed where it first decreases to 400 K and then increases, and finally becomes almost infinite at 800 K. The temperature dependent behavior of DOS and quasiparticle lifetime help us in understanding the experimentally observed electrical resistivity and Seebeck coefficient for these compounds. The calculated effective magnetic moment [Formula: see text] for Fe (∼2.5 [Formula: see text], which is closer to the experimental value) is temperature independent. The electronic structures of these compounds are showing the existence of mixed configurations with [Formula: see text] and [Formula: see text] for FeSi and CoSi, respectively. Average electrons in the d orbitals are found as  ∼6.5 and  ∼7.7 for FeSi and CoSi, respectively, with charge fluctuations [Formula: see text] 0.9 are obtained for both materials. This suggests that both the compounds are lying in the intermediate coupling regime of electronic correlations.

Evaluation of effectiveness of Mass Vaccination Campaign against Peste des petits ruminants in Chhattisgarh state, India

The study evaluated the effectiveness of 'Mass Vaccination Campaign (MVC)' implemented against the contagious transboundary OIE notified Peste des petits ruminants (PPR) in sheep and goats on the lines of 'pulse polio campaign' for humans in Chhattisgarh state, India. The effectiveness was evaluated on the axes of adequacy, financial viability under with and without MVC through differencing under various scenarios and options and programme impact from a farmer's perspective. The adequacy evaluation revealed that the reported outbreaks, diagnosed and death cases declined under PPR-MVC inconsonance with increased vaccination coverage. Furthermore, the seroconversion increased during post PPR-MVC implies elevated immunity levels in the sheep and goat population. The estimated mean mortality loss was USD 45.2 and USD 16.5 per animal in goats and sheep, respectively, whereas the treatment and opportunity cost of labour was USD 1.9 and USD 2.5 per animal respectively. Under the low PPR incidence scenario, benefit: cost ratio, net present value and internal rate of return were 4.9:1, 48.9 million USD and 146.6%, whereas it was 12.4:1,142.7 million USD and 430.4% and 13.5:1,156.7 million USD and 430.4% under medium and high incidence scenarios. Furthermore, the option of vaccinating 100% risk population during the first year followed by 30% during subsequent years to cover naïve population will maximize benefits than 100% coverage every year; nevertheless, benefits outweighs cost manifolds in both of these options. The farmers had a positive opinion on the overall services provided under PPR-MVC and the results provide the empirical evidence on effectiveness of 'mass vaccination' for its replication in other states of India or countries with similar socio-economic and rearing environments.

Role of HAMP Genetic Variants on Pathophysiology of Iron Deficiency Anemia

Hepcidin is a 25-amino acid peptide hormone produced by hepatocytes and plays a key role in body iron metabolism. Hepcidin deficiency is the cause of iron overload in hereditary hemochromatosis, iron-loading anemia, and its excess is associated with anemia of inflammation, chronic disease and iron deficiency anemia (IDA). The aims of this study was to evaluate HAMP gene mutation, namely IVS2 + 1(-G) (c.148-150 + 1del) and Gly71 Asp (c.212G > A (rs104894696) association with iron status in IDA conditions. Our study participants were 500 IDA patients and 550 age and sex-matched healthy controls. Hepcidin, ferritin and CRP analysis was done by ELISA method while ESR analysis was done according to Wintrobe method. CBC analysis was done by auto-analyzer. Two mutations in the HAMP genes were analysed by PCR RFLP method. Among the IDA patients, 7 were heterozygous for Met50del IVS2 + 1(-G) mutation. Nine IDA patients were heterozygous for G71D G-A mutation and homozygous were not identified in both mutations.Controls were showing heterozygous frequency 1.8 and 2.1% of Met50del IVS2 + 1(-G) and G71D G-A mutations respectively. Mutation of HAMP (Met50del IVS2 + 1(-G) and G71D G-A) were clinically associated with IDA and act as modulator of disease.

An important role of temperature dependent scattering time in understanding the high temperature thermoelectric behavior of strongly correlated system: La0.75Ba0.25CoO3

In the present work, we report the temperature dependent thermopower (α) behavior of La_0.75Ba_0.25CoO₃ compound in the temperature range 300-600 K. Using the Heikes formula, the estimated value of α corresponding to high-spin configuration of Co³⁺ and Co⁴⁺ ions is found to be  ∼16 [Formula: see text], which is close to the experimental value, ∼13 [Formula: see text], observed at  ∼600 K. The temperature dependent TE behavior of the compound is studied by combining the WIEN2K and BoltzTrap code. The self consistency field calculations show that the compound have ferromagnetic ground state structure. The electronic structure calculations give half metallic characteristic with a small gap of  ∼50 meV for down spin channel. The large and positive value for down spin channel is obtained due to the unique band structure shown by this spin channel. The temperature dependent relaxation time for both the spin-channel charge carriers is considered to study the thermopower data in temperature range 300-600 K. For evaluation of α, almost linear values of [Formula: see text] and a non-linear values of [Formula: see text] are taken into account. By taking the temperature dependent values of relaxation time for both the spin channels, the calculated values of α using two current model are found to be in good agreement with experimental values in the temperature range 300-600 K. At 300 K, the calculated value of electrical conductivity by using the same value of relaxation time, i.e. 0.1 [Formula: see text] 10^-14 seconds for spin-up and [Formula: see text] seconds for spin-dn channel, is found to be equal to the experimentally reported value.

Fabrication of setup for high temperature thermal conductivity measurement

In this work, we report the fabrication of an experimental setup for high temperature thermal conductivity (κ) measurement. It can characterize samples with various dimensions and shapes. Steady state based axial heat flow technique is used for κ measurement. Heat loss is measured using parallel thermal conductance technique. Simple design, lightweight, and small size sample holder is developed by using a thin heater and limited components. Low heat loss value is achieved by using very low thermal conductive insulator block with small cross-sectional area. Power delivered to the heater is measured accurately by using 4-wire technique and for this, the heater is developed with 4 wires. This setup is validated by using Bi_0.36Sb_1.45Te₃, polycrystalline bismuth, gadolinium, and alumina samples. The data obtained for these samples are found to be in good agreement with the reported data. The maximum deviation of 6% in the value κ is observed. This maximum deviation is observed with the gadolinium sample. We also report the thermal conductivity of polycrystalline tellurium from 320 K to 550 K and the nonmonotonous behavior of κ with temperature is observed.

Electronic structure of Mo1-x Re x alloys studied through resonant photoemission spectroscopy

We studied the electronic structure of Mo-rich Mo1-x Re x alloys ([Formula: see text]) using valence band photoemission spectroscopy in the photon energy range 23-70 eV and density of states calculations. Comparison of the photoemission spectra with the density of states calculations suggests that, with respect to the Fermi level E F, the d states lie mostly in the binding energy range 0 to  -6 eV, whereas s states lie in the binding energy range  -4 to  -10 eV. We observed two resonances in the photoemission spectra of each sample, one at about 35 eV photon energy and the other at about 45 eV photon energy. Our analysis suggests that the resonance at 35 eV photon energy is related to the Mo 4p-5s transition and the resonance at 45 eV photon energy is related to the contribution from both the Mo 4p-4d transition (threshold: 42 eV) and the Re 5p-5d transition (threshold: 46 eV). In the constant initial state plot, the resonance at 35 eV incident photon energy for binding energy features in the range E F (BE  =  0) to  -5 eV becomes progressively less prominent with increasing Re concentration x and vanishes for x  >  0.2. The difference plots obtained by subtracting the valence band photoemission spectrum of Mo from that of Mo1-x Re x alloys, measured at 47 eV photon energy, reveal that the Re d-like states appear near E F when Re is alloyed with Mo. These results indicate that interband s-d interaction, which is weak in Mo, increases with increasing x and influences the nature of the superconductivity in alloys with higher x.

Synthesis, spectroscopic, thermal and antimicrobial studies of neodymium(III) and samarium(III) complexes derived from tetradentate ligands containing N and S donor atoms

Trivalent lanthanide complexes of the type [Ln(L)Cl(H2O)2] (where Ln=Nd(III) or Sm(III) and LH2=Schiff bases derived by the condensation of 3-(phenyl/substitutedphenyl)-4-amino-5-mercapto-1,2,4-triazole with diacetyl/benzil) have been synthesized by the reactions of anhydrous lanthanide(III) chloride with Schiff bases in methanol. The structures of the complexes have been proposed on the basis of elemental analysis, electrical conductance, magnetic moment, spectroscopic measurements (IR, 1H, 13C NMR and UV-vis spectra) and X-ray diffraction studies. The spectral data reveal that the Schiff base ligands behave as dibasic tetradentate chelating agents having coordination sites at two thiol sulfur atoms and two azomethine nitrogen atoms. The presence of coordinated water in metal complexes was confirmed by thermal and IR data of the complexes. All the Schiff bases and their metal complexes have also been screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus and antifungal activities against Aspergillus niger, Curvularia pallescens and Colletotrichum capsici.

Emissions of amides (N,N-dimethylformamide and formamide) and other obnoxious volatile organic compounds from different mattress textile products

The emission rates of N,N-dimethylformamide (DMF), formamide (FAd), and certain hazardous volatile organic compounds (VOCs) were measured from seventeen mattress textile samples with four different raw material types: polyurethane (PU: n=3), polyester/polyethylene (PE: n=7), ethylene vinyl acetate (EV: n=3), and polyvinyl chloride (PC: n=4). To simulate the emissions in a heated room during winter season, measurements were made under temperature-controlled conditions, i.e., 50°C by using a mini-chamber system made of a midget impinger. Comparison of the data indicates that the patterns were greatly distinguished between DMF and FAd. PU products yielded the highest mean emission rates of DMF (2940 μg m(-2)h(-1): n=3) followed by PE (325 μg m(-2)h(-1): n=7), although its emission was not seen from other materials (EV and PC). In contrast, the pattern of FAd emission was moderately reversed from that of DMF: EV>PC>PE>PU. The results of our analysis confirm that most materials used for mattress production have the strong potential to emit either DMF or FAd in relatively large quantities while in use in children׳s care facilities, especially in winter months. Moreover, it was also observed that an increase in temperature (25°C to 50°C) had a significant impact on the emission rate of FAd and other hazardous VOCs. In addition to the aforementioned amides, the study revealed significant emissions of a number of hazardous VOCs, such as aromatic and carbonyl compounds.

Investigation of thermoelectric properties of half-metallic Co₂MnGe by using first principles calculations

By combining the electronic structures obtained from first principles calculations with Boltzmann transport theory we have investigated the electronic, magnetic and transport properties of the Co2MnGe Heusler compound. The density of state plots, dispersion curves and the total energy of paramagnetic and ferromagnetic (FM) phases clearly show the half-metallic FM ground state for the compound, with an indirect band gap of about 400 meV in the minority spin channel. It has an integer value of the magnetic moment equal to 5 μ(B). In the FM phase a very large value (∼ 550 µV K(-1)) of the Seebeck coefficient (S) is obtained for down-spin electrons due to the existence of an almost flat conduction band along X in the Γ direction. The two-current model has been used to find the total S and the obtained value is about 10 µV K(-1). The calculated values of the Seebeck coefficient, resistivity and electronic thermal conductivity show nice agreement with the experimental results.

Impact of integrated nutrient management on tomato yield under farmers field conditions

Field trials were conducted in farmer's field of district Chandauli, Uttar Pradesh, India to assess the impact of integrated nutrient management (INM) on the performance of tomato crop during rabi (2008) and kharif (2009) season. Before conducting trials technological gap between actual and potential productivity were analyzed by interviewing growers to find out the major causes for low yield. Overall gap in use of fertilizers was recorded 64.90 % whereas overall mean gap in technology was 43.83%. On-farm experiments on INM were conducted by applying FYM (10t ha(-1)) + (NPK (150:80:60 kg ha(-1)) followed by dipping seedling roots in 1% Azotobacter solution for 15 min and foliar spray with 20 ppm ferrous ammonium sulphate after 30, 45 and 75 days of transplantation. The plant height, root length, number of primary branches, average fruit weight increased in INM plots as compared to farm practice. The increment in yield was found to be 28.84 and 33.86% during rabi and kharif season respectively. The maximum marketable yield obtained in INM plot during kharif and rabi seasons was 1025 q ha(-1) and 955 q ha(-1) respectively, whereas as farm practice yielded 740 q ha(-1) and 713 q ha(-1) during the same seasons. The percent loss from total production was recorded 8.5 % and 8.8 % in control plot and only 4.9 % and 5.7 % in INM plot during rabi and kharif seasons respectively. The higher fruit weight and lower incidence of disease and pest were observed in INM field in comparison to farm practice. The benefit cost ratio with INM treatment was recorded 4.25 and 4.23 in rabi and kharif season respectively against the benefit cost ratio of 2.98 and 2.82 in control plot during the same respective seasons.

Nitrogen- and fluorine-doped ZrO2: a promising p-n junction for an ultraviolet light-emitting diode

In this work we study the effect of nitrogen (N) and fluorine (F) doping on the electronic properties of ZrO(2) by using ab initio electronic structure calculations. Our calculations show the importance of on-site Coulomb correlation in estimating the correct band gap of ZrO(2). The N and F doping provide hole- and electron-type impurity states in the band gap closer to the top of the valence band and the bottom of the conduction band, respectively. The formation of such impurity states may be exploited in fabricating a p-n junction expected to be useful in making an ultraviolet light-emitting diode.

Implication of local moment at Ti and Fe sites for the electrical and magneto-transport properties of degenerate semiconducting Ti₁-xFexO₂-d epitaxial films

We have investigated the effect of local magnetic moment on the electrical and magneto-transport properties of thin films of the degenerate semiconductor Ti(1-x)Fe(x)O(2-d) (x = 0,0.04). The electrical measurements of these films reveal high temperature metallic behavior and resistivity minima. The behavior below the resistivity minimum temperature is ascribed to Kondo like scattering. The coupling between the local moment and the charge carriers is reflected in the magnetoresistance measurements in these films. This work indicates competition between the magnetic ordering mechanism by J(RKKY) and the moment screening mechanism by J(Kondo). Accordingly the role of carrier density in achieving the magnetic ordering in such materials either by defect engineering or by transition metal doping is discussed.

Effect of non-magnetic impurities on the magnetic states of anatase TiO₂

The electronic and magnetic properties of TiO₂, TiO₁.₇₅, TiO₁.₇₅N₀.₂₅, and TiO₁.₇₅F₀.₂₅ compounds have been studied by using ab initio electronic structure calculations. TiO₂ is found to evolve from a wide-band-gap semiconductor to a narrow-band-gap semiconductor to a half-metallic state and finally to a metallic state with oxygen vacancy, N-doping and F-doping, respectively. The present work clearly shows the robust magnetic ground state for N-and F-doped TiO₂. The N-doping gives rise to a magnetic moment of ~ 0.4 μ(B) at the N site and ~ 0.1 μ(B) each at two neighboring O sites, whereas F-doping creates a magnetic moment of ~ 0.3 μ(B) at the nearest Ti atom. Here we also discuss the possible cause of the observed magnetic states in terms of the spatial electronic charge distribution of Ti, N, and F atoms responsible for bond formation.

Peristaltic transport of multilayered power-law fluids with distinct viscosities: a mathematical model for intestinal flows

This paper is concerned with the theoretical study of two-dimensional peristaltic flow of power-law fluids in three layers with different viscosities. The analysis is carried out under low Reynolds number and long wavelength approximations. The shapes of the interfaces are described by a system of non-linear algebraic equations which are solved numerically as streamlines. It is found that the non-uniformity in the intermediate and peripheral layers diminishes when the viscosity of the intermediate layer is increased and that of the outermost layer is kept unaltered for both the pseudo-plastic and dilatant fluids. Similar are the observations when the viscosity of the outermost layer is increased and that of the intermediate layer is kept fixed. The flow rate increases with the viscosities of the peripheral and the intermediate layers but the viscosity of the outermost layer is more effective. However, the knowledge of the effect of the viscosity of the intermediate layer facilitates us to achieve the required flow rate without disturbing the outermost layer. An increase in the flow behaviour index too favours larger flow rates. The trapping limits increase with the viscosity of the intermediate layer but decrease with the viscosity of the outermost layer and the flow behaviour index. Thus, a medicinal intervention that creates a more viscous intermediate layer and reduces pseudo plasticity may reduce constipation.

Extractive fermentation for enhanced production of alkaline phosphatase from Bacillus licheniformis MTCC 1483 using aqueous two-phase systems

A study was made to find out maximum partitioning of Bacillus licheniformis alkaline phosphatase in different ATPSs composed of different molecular weight of PEG X (X=2000, 4000, 6000) with salts (magnesium sulphate, sodium sulphate, sodium citrate) and polymers (dextran 40, dextran T500). Physicochemical factors such as effect of system pH, system temperature and production media were evaluated for partitioning of alkaline phosphatase. PEG 4000 [9.0% (w/v)] and dextran T500 [9.6% (w/v)] were selected as most suitable system components for alkaline phosphatase production by B. licheniformis based on greater partition coefficient (k=5.23). The two-phase system produced fewer enzymes than the homogeneous fermentation (control) in early stage of fermentation, but after 72 h the enzyme produced in the control system was less than that in the ATPS. Total alkaline phosphatase yield in ATPS fermentation was 3907.01 U/ml and in homogeneous fermentation 2856.50 U/ml.

Cutaneous fungal granulomas due to Alternaria spp. infection in a horse in New Zealand

Equine cutaneous fungal granulomas have been previously referred to in New Zealand (Fairley 1998), and are described in the veterinary literature from around the world, including North America and Australia (Pascoe and Summers 1981; Genovese et al. 2001; Valentine et al. 2006), but no peer-reviewed reports appear published in the literature in New Zealand. Described here is a case of multiple cutaneous fungal granulomas caused by Alternaria spp. in a horse in New Zealand.

Importance of conduction electron correlation in a Kondo lattice, Ce₂CoSi₃

Kondo systems are usually described by the interaction of the correlation induced local moments with the highly itinerant conduction electrons. Here, we study the role of electron correlations among conduction electrons in the electronic structure of a Kondo lattice compound, Ce₂CoSi₃, using high resolution photoemission spectroscopy and ab initio band structure calculations, where Co 3d electrons contribute in the conduction band. High energy resolution employed in the measurements helped to reveal the signatures of Ce 4f states derived Kondo resonance features at the Fermi level and the dominance of Co 3d contributions at higher binding energies in the conduction band. The lineshape of the experimental Co 3d band is found to be significantly different from that obtained from the band structure calculations within the local density approximations, LDA. Consideration of electron-electron Coulomb repulsion, U, among Co 3d electrons within the LDA + U method leads to a better representation of experimental results. The signature of an electron correlation induced satellite feature is also observed in the Co 2p core level spectrum. These results clearly demonstrate the importance of the electron correlation among conduction electrons in deriving the microscopic description of such Kondo systems.

Regioselective [3+2] cycloaddition of chalcones with a sugar azide: easy access to 1-(5-deoxy-D-xylofuranos-5-yl)-4,5-disubstituted-1H-1,2,3-triazoles

[3+2] Cycloaddition of 5-azido-5-deoxy-1,2-O-isopropylidene-alpha-d-xylofuranose with 1,3-diphenyl-prop-3-enones, followed by oxidation of the intermediate triazolines in a tandem manner, led to the regioselective formation of 4-benzoyl-1-(5-deoxy-1,2-O-isopropylidene-alpha-d-xylofuranos-5-yl)-5-phenyl-1H-1,2,3-triazoles in moderate to good yields.

Potato processing scenario in India: Industrial constraints, future projections, challenges ahead and remedies - A review

Indian potato (Solanum tuberosum L.) processing industry has emerged fast due to economic liberalization coupled with growing urbanization, expanding market options and development of indegenous processing varieties. India's first potato processing varieties 'Kufri Chipsona-1' and 'Kufri Chipsona-2' were developed in 1998, followed by an improved processing variety 'Kufri Chipsona-3' in 2005 for the Indian plains and first chipping variety 'Kufri Himsona' for the hills. These varieties have >21% tuber dry matter content, contain low reducing sugars (<0.1% on fresh wt) and are most suitable for producing chips, French fries and dehydrated products. The availability of these varieties and standardization of storage techniques for processing potatoes at 10-12°C with sprout suppressant isopropyl N-(3-chlorophenyl) carbamate have revolutionized the processing scenario within a short span of 10 years. Currently about 4% of total potato produce is being processed in organized and unorganized sector. Potato processing industry mainly comprises 4 segments: potato chips, French fries, potato flakes/powder and other processed products. However, potato chips still continue to be the most popular processed product. The major challenge facing the industries lies in arranging round the year supply of processing varieties at reasonable price for their uninterrupted operation, besides several others which have been discussed at length and addressed with concrete solutions.

Lithium stabilizes the polarized lens epithelial phenotype and inhibits proliferation, migration, and epithelial mesenchymal transition

Posterior capsule opacification (PCO) is a common complication of cataract surgery caused by epithelial mesenchymal transition (EMT) and aberrant lens cell growth. One path to prevention depends on maintaining the quiescent lens epithelial phenotype. Here we report that lithium chloride (LiCl) is a potent stabilizer of the lens epithelial phenotype. In lens epithelial explants (controls), at low cell density, cells readily depolarized, spread out, and proliferated. By contrast, in the presence of LiCl, cells did not spread out or exhibit migratory behaviour. Using concentrations of 1-30 mM LiCl we also showed that cell proliferation is inhibited in a dose-dependent manner. Confocal microscopy and immunohistochemistry for ZO-1 and E-cadherin showed that LiCl treatment maintained tight junctions at the apical margins of cells. Taken together with measurements of cell heights, this showed that the cells in LiCl-treated explants maintained the apical baso-lateral polarity and cobblestone-like packing that is characteristic of lens epithelial cells in vivo. Significantly, the effects of LiCl also extended to blocking the potent EMT/cataract-promoting effects of transforming growth factor beta (TGFbeta) on lens epithelial cells. In TGFbeta-treated explants, cells progressively dissociated from one another, taking on various elongated spindle shapes and strongly expressing alpha-smooth muscle actin (alpha-SMA). These features are characteristic of PCO. In both rat and human capsulorhexis explants, LiCl treatment effectively blocked the accumulation of alpha-SMA and maintained the cells in a polarized, adherent, cobblestone-packed monolayer. These findings highlight the feasibility of applying molecular strategies to stabilize lens epithelial cells and prevent aberrant differentiation and growth that leads to cataract.

The effect of aluminium phosphide on the human brain: a histological study

The study was conducted on 317 cases of poisoning in the Varanasi region, India, between January 2002 and August 2003. Aluminium phosphide (Celphos) was used by 239 victims (75.40% of the total) and was used in 69.03% of male and 30.96% of female cases. It was commoner in males from both rural and urban areas and in the 21-30 year age group. Microscopic investigation of the cerebral and cerebellar cortex showed distinct changes due to the effect of celphos. Findings in the cerebral cortex revealed disorganisation of the different layers, round shaped neurons with a convex border, degenerated Nissl granules in the cytoplasm and a deeply stained degenerated eccentric nucleus. Findings in the cerebellar cortex included degenerated neurons, the infiltration of round cells into the molecular layer and the disappearance of the processes of Purkinje cells. Degenerate nuclei were surrounded by scavenger cells in the granular layer. The subcortical zone of the brain revealed a paucity of glial cells, degeneration of nerve fibres and the appearance of necrotic patches.

Characterization of cytotoxin-producing Aeromonas caviae (strain HT10) isolated from a sulfur spring in Orissa, India

During a study of microbial diversity, a bacterial strain designated HT10, was isolated from sediment collected from an unexplored sulfur spring at Athamallik, Orissa, India. Various biochemical tests and 16S rDNA sequence analysis revealed that strain HT10 is Aeromonas caviae. The growth temperature of this strain ranged from 12 to 43 degrees C and the optimum temperature was 30 degrees C. The strain HT10 showed cytotoxic and alpha-hemolytic activity. This is the first report on the isolation of Aeromonas caviae from sulfur spring.

Imidazoline and Its Derivatives : An Overview

Imidazoline derivatives, a class of novel cationic surfactants are presently gaining importance in global detergent market due to their wide range of applications. These are extensively used mainly as fabric softeners and antistatic agents. The present communication reviews the preparation, reaction scheme, reaction rates and properties of imidazoline derivatives. The analysis of imidazoline derivatives, its mode of action, their biodegradation and various applications have also been discussed.