Investigation on thiourea crystal grown in presence of ammonium acetate

The optically good quality single crystals of thiourea crystal grown in presence of ammonium acetate have been grown by slow evaporation solution growth technique. The single crystal X-ray diffraction and FTIR have been studied for grown crystal. The UV-Vis transmittance spectrum has been recorded in the range of 200-900 nm. Theoretical calculations have been carried out to determine the linear optical constants such as extinction coefficient and refractive index. The analysis of third order non-linear optical properties like non-linear absorption coefficient (b), non-linear refractive index (n2) and susceptibility (3) have been calculated using Z-scan technique. The dielectric and mechanical strength of doped crystals have been investigated and results are discussed

Ammonia Gas Sensing Characteristics of Spin Coated Polyaniline Films

The conductive layer of emeraldine base polyaniline (PANI) thin film coated on silicon has successfully tested for ammonia. The bulk PANI powder was synthesized by oxidative polymerization of aniline using ammonium peroxidisulfate in an acidic medium and dissolved in N-methyl pyrrolidone (NMP) for coating the thin film on Silicon using spin coater. FTIR, UVvisible, and SEM were used to characterize the PANI thin film. The electrical conductivity of the PANI films has been studied by measuring the change in electrical conductivity by Four Probe Set up on exposure to ammonia gas (NH3) at different concentrations from 100 ppm to 500 ppm. margin

A comparative study of Tam3 and Ac transposition in transgenic tobacco and petunia plants

Transposition of the Anthirrinum majus Tam3 element and the Zea mays Ac element has been monitored in petunia and tobacco plants. Plant vectors were constructed with the transposable elements cloned into the leader sequence of a marker gene. Agrobacterium tumefaciens-mediated leaf disc transformation was used to introduce the transposable element constructs into plant cells. In transgenic plants, excision of the transposable element restores gene expression and results in a clearly distinguishable phenotype. Based on restored expression of the hygromycin phosphotransferase II (HPTII) gene, we established that Tam3 excises in 30% of the transformed petunia plants and in 60% of the transformed tobacco plants. Ac excises from the HPTII gene with comparable frequencies (30%) in both plant species. When the β-glucuronidase (GUS) gene was used to detect transposition of Tam3, a significantly lower excision frequency (13%) was found in both plant species. It could be shown that deletion of parts of the transposable elements Tam3 and Ac, removing either one of the terminal inverted repeats (TIR) or part of the presumptive transposase coding region, abolished the excision from the marker genes. This demonstrates that excision of the transposable element Tam3 in heterologous plant species, as documented for the autonomous element Ac, also depends on both properties. Southern blot hybridization shows the expected excision pattern and the reintegration of Tam3 and Ac elements into the genome of tobacco plants.

Role of Conserved Non-Coding Regulatory Elements in LMW Glutenin Gene Expression

Transcriptional regulation of LMW glutenin genes were investigated in-silico, using publicly available gene sequences and expression data. Genes were grouped into different LMW glutenin types and their promoter profiles were determined using cis-acting regulatory elements databases and published results. The various cis-acting elements belong to some conserved non-coding regulatory regions (CREs) and might act in two different ways. There are elements, such as GCN4 motifs found in the long endosperm box that could serve as key factors in tissue-specific expression. Some other elements, such as the AACA/TA motifs or the individual prolamin box variants, might modulate the level of expression. Based on the promoter sequences and expression characteristic LMW glutenin genes might be transcribed following two different mechanisms. Most of the s- and i-type genes show a continuously increasing expression pattern. The m-type genes, however, demonstrate normal distribution in their expression profiles. Differences observed in their expression could be related to the differences found in their promoter sequences. Polymorphisms in the number and combination of cis-acting elements in their promoter regions can be of crucial importance in the diverse levels of production of single LMW glutenin gene types

Molecular modeling of temperature dependence of solubility parameters for amorphous polymers

A molecular modeling strategy is proposed to describe the temperature (T) dependence of solubility parameter (δ) for the amorphous polymers which exhibit glass-rubber transition behavior. The commercial forcefield “COMPASS” is used to support the atomistic simulations of the polymer. The temperature dependence behavior of δ for the polymer is modeled by running molecular dynamics (MD) simulation at temperatures ranging from 250 up to 650 K. Comparing the MD predicted δ value at 298 K and the glass transition temperature (Tg) of the polymer determined from δ–T curve with the experimental value confirm the accuracy of our method. The MD modeled relationship between δ and T agrees well with the previous theoretical works. We also observe the specific volume (v), cohesive energy (Ucoh), cohesive energy density (ECED) and δ shows a similar temperature dependence characteristics and a drastic change around the Tg. Meanwhile, the applications of δ and its temperature dependence property are addressed and discussed

Emerging roles of ATF2 and the dynamic AP1 network in cancer

Cooperation among transcription factors is central for their ability to execute specific transcriptional programmes. The AP1 complex exemplifies a network of transcription factors that function in unison under normal circumstances and during the course of tumour development and progression. This Perspective summarizes our current understanding of the changes in members of the AP1 complex and the role of ATF2 as part of this complex in tumorigenesis.Fil: Lopez Bergami, Pablo Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Lau, Eric . Burnham Institute for Medical Research; Estados UnidosFil: Ronai, Zeev . Burnham Institute for Medical Research; Estados Unido

Synthesis and characterization of polypyrrole–polyvinyl alcohol composite film with various organic acids dopants and their gas sensing behavior

446-450Polypyrrole–polyvinyl alcohol (PPY-PVA ) composite films with various organic acids such as camphor sulphonic acid (CSA), dodecyl benzene sulphonic acid (DBSA) and p-toluene sulphonic acid (p-TSA), have been synthesized in situ by chemical oxidative polymerization method. These synthesized films are characterized by using electrochemical technique, conductivity measurement, UV-visible spectroscopy, FTIR and SEM. It is observed that the PPY-PVA composite films provide good electrochemical properties, conductivity as well as polymer matrix with uniform and porous surface morphology which can be used for the immobilization of biocomponent. The current-voltage characterization reveals that these films are conducting in nature with ohmic behavior. The PPY-PVA doped composites thin films are used for different concentrations (ppm) of trimethyl ammonia and ammonia gas for their sensitivity at room temperature (304K). Results reveal that with organic acids dopant electrical property and environmental stability of PPY-PVA composites film are enhanced

PPY-PVA Blend Thin Films as a Ammines Gas Sensor

Synthesis of polypyrrole–polyvinyl alcohol blend thin by in situ chemical oxidative polymerization, on glass substrate for development of Ammonia and Trimethyl ammine hazardous gas sensor. The all experimental process carried out at room temperature (304 k). These polymer materials were characterized by Chemical analyses, spectral studies (UV-visible and IR) and conductivity measurement by four –probe technique. The surface morphology as seen in the SEM image was observed to be granular, tubular, uniformly covering the entire substrate surface having porous in nature. The current–voltage characterization show that these thin films have conducting in nature having ohmic behaviors. The sensor was used for different concentration (ppm) of TMA and Ammonia gas investigation at room temperature (304 k). This study found to possess improved electrical, mechanical and environmental stability PPY-PVA films