Flavour characteristics of Piper betle L.

The betel leaves are aromatic with varied taste ranging from sweet to pungent due to the presence of essential oil. Compounds that contribute to the pungency flavour and stimulating properties of the leaf are of interest to the flavour industry. The results of investigations carried out so far on the chemical analysis of essential oil of betel leaves have been reViewed. The results of the gas chromatography and mass spectrometry (GCMS) of the oil of all the five recognized varieties of Piper betle are discussed. The yield and composition of essential oil of betel leaves have been influenced by age and position of the leaf on the stem, season of harvest, potassium nutrition etc. Promoting the use of this important essential oil in flavour industry and confectionerles so as to utilise the surplus leaves from the assembling and wholesale markets which will otherwise go waste is suggested. &nbsp

Reactivity of some tetra substituted furans and thiophenes towards BF3-Et(2)O catalysed Diels-Alder reaction

Some tetra substituted furans and thiophenes were reacted with methyl acrylate under BF3-etherate catalysed Diels-Alder conditions. While the derivatives of furan underwent Diels-Alder reaction in a facile manner, an observation of 2,5-dimethyl-3,4-dianisylthiophene undergoing Diels-Alder reaction with methyl acrylate is remarkable. (C) 1997, Elsevier Science Ltd

Purification and characterization of a 29 kDa poly(A)-binding protein from chickpea <i>(Cicer arietinum) </i>epicotyl

258-262A poly(A)-binding protein (PABP) with mol wt 29,000 has been purified from chickpea (Cicer arietillum) epicotyl by ammonium sulfate fractionation and Cibacron blue F3-GA chromatography, making a complex with poly(A) and elution of PABP-poly(A) complex at 45°C from oligo d(T)-cellulose . The elution pattern and binding properties show that the purified protein is different from the PABP (mol. wt 72,000) reported earlier from our laboratory

Purification and characterization of a poly(A)-binding protein from chickpea (<i>Cicer arietinum) </i>epicotyl

107-113A poly(A)-binding protein (PABP) with mol wt 72,000 has been purified from chickpea (Cicer arietinum) epicotyls by ammonium sulfate fractionation , Cibacron blue F3-GA and poly(A) agarose chromatography. The binding properties and the specificity of binding show that the purified protein is an analogue of PABPs in other eukaryotes. This PABP is highly susceptible to proteolysis and upon degradation forms a polypeptide fragment of mol wt 21,000 which has an independent poly(A) binding activity

A comparison of the DNMR behaviour of methyl 5,6-bis(2-methoxyphenyl)-1,4-dimethyl-7-oxobicyclo[2.2.1]hept-5-en-2-<i style="mso-bidi-font-style:normal">endo</i>-carboxylate and its 7-oxa analogue

735-741Methyl 5,6-Bis(2-methoxyphenyl)-1,4-dimethyl-7-oxobicyclo[2.2.1] hept-5-en-2-endo-carboxylate, a moderately crowded norbornenone ester, exhibits complex VT-DNMR behav iour. A similar behaviour is not seen in its 7-oxa analogue, showing that conformational transmission from position 7 has a crucial influence on the distance parameters that govern the dynamic processes involving the substituents on the bicycloheptene framework

SLL REDUCTION IN APERIODIC LINEAR ARRAY ANTENNA SYSTEM WITH SCAN ANGLES

ABSTRACT: In modern wireless communication system one of the criteria is control over the antenna beam pattern. Antenna array provides better control over the beam pattern and provides flexibility of scanning in the required direction. The important parameter for consideration in array is spacing between elements. As the spacing between elements is increased beyond half wavelength, the steerability from broadside will significantly reduce due to appearance of grating lobe. In this paper a model of thinned aperiodic linear phased arrays is presented. Differential Evolution algorithm is used for synthesizing the performance of peak side lobe levels Keywords: Antenna arrays, Differential Evolution algorithm, Driving point impedance, Scan angle, thinned aperiodic arrays. I.INTRODUCTION The traditional way of creating linear thinned array is by exciting a number of elements in a uniform spaced linear array. The first thinned array was created by removing elements randomly or by trial and error Ошибка! Источник ссылки не найден., Ошибка! Источник ссылки не найден. . The problem with this arbitrary technique was poor side lobe suppression. This is due to the non-optimal locations of radiating elements. The recent work in thinned arrays made use of different optimization algorithms to remove elements in such a way to have minimum peak side lobe level. Most work on thinning arrays is concentrated only in optimizing an array with low side lobe levels at broadside. As these arrays are scanned a small angle away from broadside, grating lobe appears Ошибка! Источник ссылки не найден., Ошибка! Источник ссылки не найден.. This paper presents a model of thinned aperiodic linear phased arrays for various scan angles. DE algorithm is used for synthesizing the performance of peak side lobe levels. The optimization process causes the perturbation added to each element in periodic array to create an aperiodic array. II. ANTENNA ARRAY CONFIGURATION For a single element antenna the dimension of element gives the aperture. For linear array, the aperture is decided by the distance between two farthest elements. With the help of antenna arrays pattern control and beam scanning are possible. A basic array geometry and coordinate system is shown i

<span style="font-size: 19.5pt;mso-bidi-font-size:14.5pt;font-family:"Times New Roman","serif"; color:black">A systemic resistance inducing antiviral protein with N-glycosidase activity from <i>Bougainvillea xbuttiana </i>leaves </span>

600-603<span style="font-size: 13.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif";="" color:black"="">An antiviral protein from Bougainvillea xbuttiana leaves induced systemic resistance in host plants N. glutinosa and Cyamopsis tetragonoloba against TMV and SRV, respectively which was reversed by actinomycin D, when applied immediately or shortly after antiviral protein treatment. When the inhibitor was applied to the host plant leaves post inoculation, it was effective if applied upto 4 h after virus infection. It <span style="font-size:13.5pt;mso-bidi-font-size:8.5pt; font-family:" times="" new="" roman","serif";color:black"="">also delayed the expression of symptoms in systemic hosts of TMV. The inhibitor showed characteristic N- glycosidase activity on <span style="font-size:14.5pt;mso-bidi-font-size: 9.5pt;font-family:" times="" new="" roman","serif";color:black;mso-bidi-font-style:="" italic"="">25S <span style="font-size:13.5pt;mso-bidi-font-size: 8.5pt;font-family:" times="" new="" roman","serif";color:black"="">rRNA of tobacco ribosomes, suggesting that it could also be interfering with virus multiplication through ribosome-inactivation process. </span

Purification and properties of antiviral proteins from the leaves of <i><span style="font-size:14.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-ansi-language:EN-US;mso-fareast-language:EN-US; mso-bidi-language:AR-SA">Bougainvillea xbuttiana</span></i>

342-347A non-phytotoxic, resistance inducing, proteinaceous antiviral principle was purified by ammonium sulphate fractionation, ion exchange chromatography and gel filtration from the leaves of Bougainvillea xbuttiana. It imparted resistance against tobacco mosaic virus (TMV) and sunnhemp rosette virus (SRV) in their respective test hosts viz. Nicotiana gilutinosa, N. tabacum var. Samsun NN, and Cyamopsis tetragonoloba, respectively. The purified principle eluted as a single peak upon gel filtration, but exhibited two polypeptides on SDS-PAGE with Mr 28,000 and 24,000. The two polypeptides were found to be highly basic, rich in lysine with <span style="font-size:14.0pt;font-family:Arial; mso-fareast-font-family:" times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">pI <span style="font-size:14.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">around 10.0 and 10.5, respectively. Since this principle effected local lesion inhibition in both treated and untreated top leaves of test host, it might be acting in the initial stages of virus infection as a systemic inducer.</span

RNA Cleavage Properties of Nucleobase-Specific RNase MC1 and Cusativin Are Determined by the Dinucleotide-Binding Interactions in the Enzyme-Active Site

Knowledge of the cleavage specificity of ribonucleases is critical for their application in RNA modification mapping or RNA-protein binding studies. Here, we detail the cleavage specificity and efficiency of ribonuclease MC1 and cusativin using a customized RNA sequence that contained all dinucleotide combinations and homopolymer sequences. The sequencing of the oligonucleotide digestion products by a semi-quantitative liquid chromatography coupled with mass spectrometry (LC-MS) analysis documented as little as 0.5&ndash;1% cleavage levels for a given dinucleotide sequence combination. While RNase MC1 efficiently cleaved the [A/U/C]pU dinucleotide bond, no cleavage was observed for the GpU bond. Similarly, cusativin efficiently cleaved Cp[U/A/G] dinucleotide combinations along with UpA and [A/U]pU, suggesting a broader specificity of dinucleotide preferences. The molecular interactions between the substrate and active site as determined by the dinucleotide docking studies of protein models offered additional evidence and support for the observed substrate specificity. Targeted alteration of the key amino acid residues in the nucleotide-binding site confirms the utility of this in silico approach for the identification of key interactions. Taken together, the use of bioanalytical and computational approaches, involving LC-MS and ligand docking of tertiary structural models, can form a powerful combination to help explain the RNA cleavage behavior of RNases