Stabilization of Guanidinate Anions [CN3]5− in Calcite-Type SbCN3

The stabilization of nitrogen-rich phases presents a significant chemical challenge due to the inherent stability of the dinitrogen molecule. This stabilization can be achieved by utilizing strong covalent bonds in complex anions with carbon, such as cyanide CN⁻ and NCN²⁻ carbodiimide, while more nitrogen-rich carbonitrides are hitherto unknown. Following a rational chemical design approach, we synthesized antimony guanidinate SbCN₃ at pressures of 32–38 GPa using various synthetic routes in laser-heated diamond anvil cells. SbCN₃, which is isostructural to calcite CaCO₃, can be recovered under ambient conditions. Its structure contains the previously elusive guanidinate anion [CN₃]⁵⁻, marking a fundamental milestone in carbonitride chemistry. The crystal structure of SbCN₃ was solved and refined from synchrotron single-crystal X-ray diffraction data and was fully corroborated by theoretical calculations, which also predict that SbCN₃ has a direct band gap with the value of 2.20 eV. This study opens a straightforward route to the entire new family of inorganic nitridocarbonates.     

In Silico Mining of Conserved miRNAs of Indian Catfish <Emphasis Type="Italic">Clarias batrachus</Emphasis> (Linnaeus, 1758) from the Contigs,ESTs, and BAC End Sequences

MicroRNAs are small non-coding RNAs which play significant role in RNA interference. The present work deals with mining of the conserved miRNA and their target genes from the contigs, ESTs, and BAC end sequences of commercially important catfish, Clarias batrachus, from India. A total of 138, 1 and 1 conserved pre-miRNA sequences, were mined from the contigs, ESTs, and BAC end sequences, respectively. The analysis of families of the conserved pre-miRNA revealed conservation of the fish-specific family mir-430 and other important families, such as mir-455, let-7, mir-133, and mir-137. The mir-455 is involved in hypoxia signaling, let-7 family represents potential anti-tumor molecules involved in human cancer therapy, whereas mir-133 and mir-137 have high therapeutic potentials. Using an alternate computational in silico approach, mining of mature miRNAs resulted in identification of 210 mature miRNAs from contigs, 1 from EST, and 2 each from forward as well as reverse BAC end sequences. Target prediction of these putative miRNAs resulted in the identification of 66,758 and 18,747 target genes in C. batrachus and Danio rerio, respectively. Functional annotation of these miRNAs indicated their involvement in diverse biological functions. The findings of the present study can serve as a valuable resource for further functional genomics studies in C. batrachus.     

Interaction of a weak discontinuity wave with a characteristic shock in a dusty gas

In this paper, the evolution of a characteristic shock in a dusty gas is investigated and its interaction with a weak discontinuity wave is studied. The transport equation for the amplitude of the weak discontinuity wave, which is of Bernoulli type, is obtained. The amplitudes of the reflected and transmitted waves after interaction of the weak discontinuity with the characteristic shock are evaluated by using the results of the general theory of wave interaction.      

Laser Raman spectroscopic study of water in gelatin–surfactant solutions and gels

A Raman spectroscopic study was carried out on water in gelatin at 4% w/v in gel (25 °C) and sol (40–60 °C) states at various concentrations (0.5, 1, 5, 10 and 15 mM) of anionic surfactant, sodium dodecyl sulfate (SDS). The in-phase collective stretching mode vibration of hydrogen-bonded -OH oscillators, centered around 3250 cm⁻¹ in a tetrahedral network of water molecules, was observed to be significantly affected by temperature and the presence of SDS. According to our observation this may be due to the thinning of the hydration water around the gelatin molecules due to strong thermal agitation. The peak center of the collective bands of water decreased linearly with SDS concentration in the gel state which implied that with the increase in concentration of SDS, the -OH oscillators gradually lost their attachment to gelatin chains and were replaced by SDS molecules. Ultimately this resulted in a thinning of the hydration layer around the gelatin and the oscillation frequency of -OH oscillators moved towards 3250 cm⁻¹ at 1 mM SDS concentration resulting in increased coupling of -OH oscillators to form the tetrahedral network at the critical micelle concentration (cmc) of SDS. The variation in the peak amplitudes and the systematic reversal of their trend about the cmc axis was surprising. At 40 °C the amplitude of the peak at 3250 cm⁻¹ increased drastically due to a possible coil expansion by about 7–8% which accommodated more interstitial water into the pseudonetwork leading to an increase in the number of nearest neighbors and for about 6% increase in the C value. However, at the cmc the peak amplitude was observed to be independent of temperature. Continuous shifting of the peak center and full width at half-maxima towards lower values was observed with increasing SDS concentrations in the gel state. Received: 28 September 1998 Accepted in revised form: 8 March 1999     

Bacterial synthesized metal and metal salt nanoparticles in biomedical applications: An up and coming approach

In the present scenario, metal nanoparticles have elicited a great deal of interest in biomedical applications because of their unique properties and antimicrobial potentials. Over the past few years, the green nanotechnology has materialized as a momentous approach for the synthesis and fabrication of noble metal salt and metal nanoparticles. The green route synthesis exploits diverse reducing and stabilizing agents from bacterial resources for the successful synthesis of metal nanoparticles. This review mainly focuses on the biosynthesis of the most commonly studied metal and metal salt nanoparticles such as gold, silver, platinum, palladium, copper, cadmium, titanium oxide, zinc oxide, zinc sulphate, cadmium sulphide and many more. These noble nanoparticles can be exploited in pharmaceutical industry as antimicrobial and anti-biofilm agents, targeted delivery of anticancer drugs, biosensors, etc.     

Monitoring the phase evolution in LiCoO2 electrodes during battery cycles using in-situ neutron diffraction technique

LiCoO₂ (LCO) with average particle distribution of 8 μm (LCO-A) and 11 μm (LCO-B) exhibit substantial differences in cycle performance. The half-cells have similar first-cycle discharge capacities of 173 and 175 mAh/g at 0.25 C, but after 100 cycles, the discharge capacities are substantially different, that is, 114 and 141 mAh/g for LCO-A and LCO-B, respectively. Operando neutron powder diffraction of full LCO||Li₄Ti₅O₁₂ batteries show differences in the LCO reaction mechanism underpinning the electrochemical behavior. LCO-A follows a purely solid solution reaction during cycling compared to the solid solution and two-phase reaction mechanism in LCO-B. The absence of the two-phase reaction in LCO-A is consistent with a homogeneous distribution of Li throughout the particle. The two-phase reaction in LCO-B reflects two distinguishable distributions of Li within the particles. The faster capacity decay in LCO-A is correlated to an increase in electrode cracking during battery cycles.     

Elevated viscosities in a simulated moving bed for γ‐aminobutyric acid recovery

Process streams of agro‐food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub‐sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ‐aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ‐aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.     

Effect of uranium oxide loading on the enthalpy increment (∆H) and heat capacity (Cp) values of modified borosilicate glass for radwaste immobilisation

Journal of Thermal Analysis and Calorimetry - Enthalpy increments (?H) of alkali borosilicate glasses (BSG) with and without uranium oxide were measured by drop calorimetry. The heat capacity...     

A 3D‐QSAR Study of Celebrex‐Based Pdk1 Inhibitors Using Comfa Method

A 3D‐QSAR study of celebrex‐based compounds of PDK1 inhibitors using comparative molecular field analysis (CoMFA) was carried out. The structures of the compounds were obtained using quantum chemistry calculation. CoMFA calculations for a number of grouped subsets of compounds gave q² values of correlation in the range from 0 to 0.8. The low q² values should be mainly due to the narrow span of biological activity. Calculations for several subsets of 11–13 compounds gave high q² values, with 0.5–0.8. Factors affecting the results of the calculations are discussed. Calculated results with high q² values suggest that further chemical modifications of the compounds could lead to enhanced activity and could be an aid in the design of celebrex‐based cancer drugs.