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Pearl millet [Pennisetum glaucum (L.) R. Br.] is an important component of agri‐food system in areas experiencing drought and high temperature and for increasing the resilience to climatic stresses and addressing malnutrition. The purpose of this review is to examine strategies for improving productivity, stress resilience, and nutritional quality of pearl millet and to understand its consumption pattern. Genetic diversification of hybrid parental lines remains strategically important to breed diverse, disease‐resistant and drought‐tolerant hybrids. Resistance to diseases, tolerance to drought, and high temperature and greater contents of iron and zinc are targeted in improving hybrid parental lines. Lodging resistance, compact panicles, panicle exertion, and improved seed set are universal traits, whereas duration, tillering ability, seed color, and seed size have a strong regional preference. The strategy of developing high‐yielding and disease‐resistant hybrids with adaptation to challenged agro‐ecologies has led to increase in yield from 303 to 1219 kg/ha between 1960 and 2020. Yield and stress resilience are to be increased further using conventional breeding and new tools like genomic selection, speed breeding, genome editing, and precision phenotyping. Mainstreaming grain nutritional traits, viz., iron and zinc contents in genetic improvement are essential to develop high‐yielding and nutrient‐rich pearl millet. There is need to enhance the consumption of pearl millet by strengthening existing value‐chain, providing consumer a choice of diverse range of food products, creating awareness about its health benefits and promotion through government schemes. Core Ideas: Pearl millet has an important role in increasing climatic resilience of agri‐food system and reducing malnutrition.Strategies of enhancing yield focused on hybrid development, disease resistance, and genetic diversification.Use of adapted germplasm and elite materials proved effective in amalgamating drought tolerance and productivity.In future, yield is to be increased along with resilience using conventional, genomics‐assisted, and speed breeding.There is need to enhance the consumption of nutritious pearl millet by strengthening value‐chain and creating awareness. Plain Language Summary: Pearl millet is an important component of agri‐food system in areas experiencing drought and high temperature. It would have a greater role in future for increasing the resilience to climate stresses and as nutrient‐rich crop for addressing malnutrition. The purpose of this review is to examine strategies for improving productivity, environmental resilience, and nutritional quality of pearl millet and to understand its consumption dynamics. Yield improvement remains a top priority in breeding high‐yielding cultivars. Strategies of enhancing yield were influenced by availability of new knowledge and opportunities. Programs up to 1960s focused on the development of open‐pollinating varieties using a diverse range of genetic resources. Discovery of cytoplasmic male sterility (CMS), availability of stable male‐sterile lines, and effective restorers created new opportunities to exploit heterosis at the commercial scale through the development of hybrids that provided 15%–20% yield advantage over traditional cultivars. [ABSTRACT FROM AUTHOR]

The Palaeogene sedimentary succession of the Inner Fold Belt, exposed in Botsa, Kohima District of Nagaland, contains a rich ichnofossil assemblage, with trace fossils being common in the lower part. The present investigation was aimed at establishing the palaeoenvironmental conditions of the Palaeogene sedimentary rocks of the study area. Based on the various parameters, two lithofacies; siltstone‐sandstone and mudstone facies have been identified. The trace fossils recorded comprise 10 ichnogenera representing 12 ichnospecies namely, Chondrites intricatus, Diplocraterion isp., Lockeia siliquaria, Monocraterion isp., Nereites isp., Palaeophycus tubularis, Planolites beverleyensis, Scolicia plana, Scolicia prisca, Skolithos verticalis, Thalassinoides horizontalis and Thalassinoides suevicus. Based on integrated lithofacies and trace fossils analysis, an upper shoreface to offshore transition shallow marine palaeoenvironment with fluctuating energy conditions is envisaged for the Palaeogene sedimentary rocks of the study area. [ABSTRACT FROM AUTHOR]

Raman and photoluminescence spectroscopic studies on oxygen vacancy‐induced structural disorder in Gd2Ti2O7‐δ single crystals grown by optical floating zone technique under argon atmosphere are reported. The oxygen vacancies in Gd2Ti2O7‐δ wafers decrease with thermal annealing in air atmosphere. The full width at half maximum of X‐ray diffraction rocking curve decreases from 245 to 157 arcsec and the optical transmittance increases from 23% to 87% (at 1000 nm) upon post growth thermal annealing. Raman spectroscopic studies reveal a monotonic increase in intensity of O–Gd–O (Eg) and Ti–O (A1g) stretching modes with thermal annealing. Since these modes are associated with modulation of oxygen x parameter which is sensitive to Ti–O octahedron distortion, the increase in Raman intensity indicates an improvement in structural ordering of oxygen sub‐lattice in Gd2Ti2O7‐δ. Moreover, the photoluminescence studies also corroborate the Raman analysis in terms of reduction of structural defects associated with oxygen vacancies as a function of thermal annealing. This study demonstrates the effectiveness of using Raman spectroscopy to probe the structural disorder in Gd2Ti2O7‐δ crystals. [ABSTRACT FROM AUTHOR]

Oligocene Barail sandstones in parts of the Naga Hills, west of Kohima town, Nagaland, north‐east India have been studied for their provenance and tectonic environments using mineral assemblages and heavy mineral contents. Moderate to well‐sorted litharenite to sublith‐arenite Barail sandstones are dominated by monocrystalline quartz and are represented by both undulose and non‐undulose varieties. Of the two feldspars, plagioclase dominates over K‐feldspar. Rock fragments are second in abundance and constituted of chert, siltstones, schist, and volcanic fragments. The heavy mineral assemblage of Barail sandstones is represented by euhedral, subhedral/subrounded, and well‐rounded zircon, tourmaline, rutile, staurolite, sillimanite, and kyanite. Opaques are represented by rounded iron oxides. Detailed petrography coupled with heavy mineral assemblage points towards a mixed provenance dominated by a sedimentary source of recycled orogenic provenance in a foreland basinal set‐up. Our study further reveals that sediments were mainly supplied from a north‐east direction. However, at the higher stratigraphic levels, contributions were also made from the west. In response to changing plate interaction with time, contributions were made from the Indo‐Myanmar Ranges, the Shillong Plateau and/or the Karbi‐Anglong Massif, and also from the sediments formed under earlier tectonic regimes of the Assam‐Arakan Orogenic Belt. [ABSTRACT FROM AUTHOR]

An experimental study of native oxidation of silicon during electron beam evaporation is carried out. A set of SiOx thin films is prepared at varying e‐beam current (50–300 mA) without inflow of oxygen gas from external supply. The O:Si stoichiometry ratio of grown SiOx films, as estimated through X‐ray photoelectron spectroscopy (XPS) measurement, is found to be mainly governed by the deposition rate. Optical analysis using transmission spectrophotometry and spectroscopic ellipsometry measurements reveal gradual variation of refractive index (1.58–4.09@650 nm) and bandgap (3.65–1.90 eV) of grown films with the increase in e‐beam current. Such high contrast changes in Si‐based optical materials just by variations of e‐beam current are not reported previously. Deposition rate‐dependent oxidation and optical constants are confirmed by investigating two separate films at lower substrate heights. Finally, utilizing the quasicontinuous variation of optical constants of SiOx films, antireflection (AR) coating is designed and experimentally demonstrated on Si wafer and achieved reflectance loss of ≈2.7% in wavelength range of 400–900 nm. The native oxidation under varying e‐beam current is envisaged to be an effective and a facile method for preparing quasicontinuously tunable silicon‐based optical materials. [ABSTRACT FROM AUTHOR]

Homogeneous multiwalled carbon nanotube/montmorillonite hybrid filler (HMM) dispersion was prepared by co‐ultrasonication and was subsequently used to prepare ethylene‐co‐vinyl acetate (EVA) nanocomposites by solution blending method. XRD and TEM analysis of HMM confirm significant interaction between the montmorillonite (MMT) layers and multiwalled carbon nanotubes (MWCNT) in line with previous reports. Analysis of the nanocomposites shows the constituent fillers to be homogeneously dispersed in EVA matrix. Mechanical properties of neat EVA are remarkably improved with HMM content up to 3 wt% followed by reversion. Maximum improvement observed in tensile strength, elongation at break, and toughness are 424%, 109%, and 1122%, respectively. Results show maximum thermal stability at 4 wt% and best dielectric response at 1 wt% HMM content. Exceptional mechanical and dielectric properties of EVA nanocomposites attained may be attributed to homogeneous dispersion of fillers and improved polymer–filler interaction. Comparison shows excellent synergy between MWCNT and MMT towards mechanical reinforcement of EVA. POLYM. ENG. SCI., 58:1155–1165, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The fatigue life prediction model based on crack propagation from micro-structural features is derived and presented for planar and randomly oriented Discontinuous Reinforced Metal Matrix Composites (DRMMCs). The model contains the influence of micro-structural properties such as aspect ratio, volume fraction of particle/fibre and constraint between particle and the matrix. The effect of residual thermal stresses generated within the matrix during development of composite is considered. The particle/fibre plays a dominant role in the development of the cyclic plastic zone size ahead of the crack tip; moreover, it enhances the cyclic plastic deformation characteristics of DRMMC. The theoretical model-based evaluations for low cycle fatigue in DRMMCs are within the proximity of the experimental results. [ABSTRACT FROM AUTHOR]

ABSTRACT A new synthetic route was applied to develop carbon nanofiber (CNF)-layered double hydroxide (LDH) hybrid through a noncovalent assembly using sodium dodecyl sulfate as bridging linker between magnesium-aluminum LDH and CNF and then characterized. Furthermore, this hybrid was used as nanofiller in thermoplastic polyurethane-acrylonitrile butadiene rubber (TN; 1:1 w/w) blend. Mechanical measurements showed that the 0.50 wt % hybrid loaded TN blend exhibited the maximum improvements in the elongation at break, tensile strength, and storage modulus of 1.51 times and 167 and 261% (25 °C), respectively. Differential scanning calorimetric analysis and thermogravimetric analysis showed maximum improvements in the melting temperature (5 °C), crystallization temperature (17 °C), and thermal stability (14 °C) in the 0.50 wt % surfactant modified carbon nanofiber-LDH loaded blend compared to the neat blend. Such enhancement in the properties of the TN nanocomposites could be attributed to the homogeneous dispersion, strong filler-blend interfacial interaction, and synergistic effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43470. [ABSTRACT FROM AUTHOR]

A theory for evaluating the temperature variation of second, third and fourth order elastic constants (SOECs, TOECs and FOECs) for face centred cubic crystal structure solids is developed on the basis of Coulomb and Born-Mayer potential using nearest-neighbour distance and hardness parameter. The theory thus obtained is first applied to get the higher order elastic constants for TiC and TiN crystals at different temperatures. In addition to elastic properties we have reported electronic properties of these titanium based compounds using Spin Polarised Relativistic Korringa-Kohn-Rostoker (SPR-KKR) method based on Green Function theory. Energy bands are interpreted in term of density of states. The effect of temperature on higher order elastic constants is discussed in view of the theory proposed. A crossover in energy bands predicts that TiC and TiN are metallic in nature which is in tune with available data. [ABSTRACT FROM AUTHOR]

Stellaria devendrae sp. nov. (Caryophyllaceae) is here described and illustrated from the Uttarakhand state of the Indian western Himalaya. It differs from the allied S. monosperma Buch.-Ham. ex D. Don and S. paniculata Edgew. in having sub-sessile, oblanceolate or obovate leaves with non amplexicaul, rounded to sub-auricled leaf base; an inflorescence of a terminal, regularly and simply branched panicle of cymes; larger flowers (5-8 mm across); 5-lobed floral disc; relatively larger sepals (4-7 mm long); petal lamina lobed for more than 1/2 to 4/5 of the lamina; filaments opposite sepals with prominent nectar glands at base; adjoining filaments not fused at base, and an inconspicuously reticulate-papillate seed surface. [ABSTRACT FROM AUTHOR]

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BACKGROUND An unstructured model for batch culture production of L-asparaginase by Bacillus aryabhattai ITBHU02, by means of the Luedeking-Piret incorporated logistic equation, was developed explaining the correlation between growth dynamics and enzyme production kinetics with respect to glucose depletion at different levels. The main goal was to build up a means for process optimization, design, control and analysis of L-asparaginase production. Various thermodynamic parameters were estimated to comprehend enzyme stability and affiliated industrial applicability. RESULTS Specific growth rate maxima were increased with increasing initial glucose concentration, whereas the specific productivity was best supported at a glucose concentration 5.0 g L-1. The fermentative production of L-asparaginase was greatly influenced by oxygen supply, reaching a maximum level at an aeration rate of 0.6 vvm. The activation energies for growth and death rate were 33.8±6.0 and 99.8±9.0 kJ mol-1, respectively, with activation enthalpy values of enzyme formation and thermal deactivation 70.2±9.0 and 46.1±11.0 kJ mol-1, respectively. CONCLUSION The economic production of L-asparaginase by B. aryabhattai was achieved efficiently at low glucose concentration and mild aeration. Endogenous metabolism of the strain for L-asparaginase synthesis was thermostable up to 40°C, which makes the strain commercially important as it can be utilized for cost-effective L-asparaginase production within countries such as India, where 35-40°C temperatures are quite common. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The long-term oxidation performance of an alloy is critically linked to the early-stage oxidation behavior of high-temperature alloys. This study investigates early-stage oxidation behavior in terms of oxidation kinetics, scale evolution, and residual stresses developed within a scale of the commercially available cobalt-rich alloys: HAYNES® 188, 6B, 25, and HR-160® and a newly developed nitride-dispersion strengthened NS-163® alloy (HAYNES®, HR-160®, NS-163® are registered trademarks of Haynes International, Inc). Short-term isothermal oxidation exposures were conducted in flowing air at 982 °C for durations of 1-50 h. Oxidation kinetics was assessed by weight-change behavior, which showed that 188 alloy exhibited the lowest weight-gain, while for similar times HR-160 alloy underwent weight-loss. SEM/EDS analysis was performed to characterize oxides formed in these alloys, while stresses developed in the oxides of different alloys were measured using synchrotron X-ray radiation. The results in this paper clearly demonstrated the effects of alloy composition on the scale evolution and the amount of stresses developed in oxides. [ABSTRACT FROM AUTHOR]

The synthesis of a new series of 4-aryl-3-chloro-2-oxo- N-[3-(10 H-phenothiazin-10-yl)propyl]azetidine-1-carboxamides, 4a- 4m, is described. Phenothiazine on reaction with Cl(CH2)3Br at room temperature gave 10-(3-chloropropyl)-10 H-phenothiazine ( 1), and the latter reacted with urea to yield 1-[3-(10 H-phenothiazin-10-yl)propyl]urea ( 2). Further reaction of 2 with several substituted aromatic aldehydes led to N-(arylmethylidene)- N′-[3-(phenothiazin-10-yl)propyl]ureas 3a- 3m, which, on treatment with ClCH2COCl in the presence of Et3N, furnished the desired racemic trans-2-oxoazetidin-1-carboxamide derivatives 4a- 4m. The structures of all new compounds were confirmed by IR, and 1H- and 13C-NMR spectroscopy, FAB mass spectrometry, and chemical methods. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the preparation of thermoplastic polyurethane (PU) nanocomposites by using solution intercalation method. It notes the use of dodecyl layered double hydroxide (DS-LDH) in the study, as well as X-ray diffraction and transmission electron microscopy analysis. Results of the study showed an improvement in the mechanical properties of nanocomposite containing DS-LDH.

The article discusses the preparation of ethylene vinyl acetate (EVA-45)/ethylene propylene diene terpolymer (EPDM) blend-layered double hydroxide (LDH) nanocomposites via solution bending with varying amounts of organo LDH (DS-LDH). These nanocomposites were investigated by x-ray diffraction and transmission electron microscopy, and measuring their mechanical properties revealed that they have greater tensile strength and elongation at break than EVA/EPDM blends. Dynamic mechanical thermal analysis was also used to evaluate the storage modulus of the polymers at glass transition temperature. Scanning electron microscopy revealed improvements in fracture behavior.

The article examines the preparation of the rubber nanocomposites containing ethylene vinyl acetate (EVA) having 60 wt % of vinyl acetate content and organomodified layered double hydroxide (DS-LDH) as nanofiller. XRD and TEM analysis showed the formation of totally exfoliated EVA/DS-LDH nanocomposites for 1 wt % filler loading followed by partly exfoliated structure for 5-8 wt % of DS-LDH content. The nanocomposites exhibited improved tensile strength and elongation at break.

India is like a microcosm of the world in terms of its diversity; religion, climate and ethnicity which leads to genetic variations in the populations. As a highly polymorphic marker, the human leukocyte antigen (HLA) system plays an important role in the genetic differentiation studies. To assess the genetic diversity of HLA class II loci, we studied a total of 1336 individuals from north India using DNA-based techniques. The study included four endogamous castes (Kayastha, Mathurs, Rastogies and Vaishyas), two inbreeding Muslim populations (Shias and Sunnis) from north India and three northeast Indian populations (Lachung, Mech and Rajbanshi). A total of 36 alleles were observed at DRB1 locus in both Hindu castes and Muslims from north, while 21 alleles were seen in northeast Indians. At the DQA1 locus, the number of alleles ranged from 11 to 17 in the studied populations. The total number of alleles at DQB1 was 19, 12 and 20 in the studied castes, Muslims and northeastern populations, respectively. The most frequent haplotypes observed in all the studied populations were DRB1*0701-DQA1*0201-DQB1*0201 and DRB1*1501-DQA1*0103-DQB1*0601. Upon comparing our results with other world populations, we observed the presence of Caucasoid element in north Indian population. However, differential admixturing among Sunnis and Shias with the other north Indians was evident. Northeastern populations showed genetic affinity with Mongoloids from southeast Asia. When genetic distances were calculated, we found the north Indians and northeastern populations to be markedly unrelated. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the exfoliation of magnesium aluminum layered double hydroxide (LDH) nanolayers with ethylene vinyl acetate (EVA) matrix and the effect of filler loading on the mechanical and thermal properties of EVA/dodecyl sulphate-LDH (DS-LDH) nanocomposites. Results of the study showed that EVA-45 nanocomposites with DS-LDH content exhibited higher tensile strength and elongation than neat EVA-45.

The leaves of Indian yew Taxus wallichiana, growing in Gulmarg, Jammu and Kashmir, on hydrodistillation, gave 0.025% oil on a fresh weight basis. GC and GC-MS analysis of the oil resulted in the identification of 62 constituents, representing 93.3% of the oil. The main constituents identified in the leaf oil were ( E)-2-octen-1-ol (14.5%), n-pentacosane (8.1%), caryophyllene oxide (7.1%), 1-octanol (6.5%), hexanoic acid (5.5%) and ( Z)-3-hexenol (4.1%). Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses the development of a new ternary nanocomposite by solution method. The nanocomposite was developed using ethylene propylene diene terpolymer, ethylene vinyl acetate copolymer and organically modified layered silicate from sodium morillonite. A certain amount of organically modified layered silicate loadings has been measured and its mechanical properties showed a significant increase in tensile strength, elongation at break, and modulus at different elongations.

The rhizome essential oils of Curcuma angustifolia from Central and Southern India were subjected to GC/MS analysis, which resulted in the identification of 81 and 78 constituents, accounting for more than 95 and 99% of the oil contents, respectively. The major constituents in the rhizome oil from Central India were xanthorrhizol isomer (12.7%), methyl eugenol (10.5%), palmitic acid (5.2%) and camphor (4.2%), while the rhizomes oil from Travancore (Southern India) had germacrone (12.8%), camphor (12.3%), isoborneol (8.7%), curdione (8.4%) and 1,8-cineole (4.8%) as major constituents. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The essential oil composition of four accessions, C-62, P-17, C-45 and C-59, with control LK of Mentha × piperita, cultivated at the CIMAP Research Farm, Lucknow, were analysed by GC and GC-MS, which resulted in the identification of 61, 74, 67, 68 and 55 constituents, representing 99.7%, 99.6%, 99.7%, 92.3% and 91.6% of the oils, respectively. The performance of accessions C-62, P-17, C-45 and C-59 against the control LK was also evaluated. The yield of fresh material, 17.2, 18.2, 17.5, 16.4 and 18.0 tons/ha, and the production of essential oils, 72.6, 145.5, 80.1, 74.6 and 75.8 kg/ha, was satisfactory. Accessions C-62, C45 and P-17 were found suitable for cultivation of peppermint, with acceptable amounts of menthol, menthone and menthyl acetate. It is interesting to observe that menthofuran was also absent in all the four accessions except the control. The essential oil of accession P-17 was superior over the other accessions, with an almost twice higher oil yield and an oil profile composition comparable to those of other accessions. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The essential oils of Palmarosa ( Cymbopogon martinii (Roxb.) Wats. var. motia Burk) flowering herbs from three different geographical locations in India, viz. Hyderabad,Lucknow and Amarawati were analysed by high-resolution GC and GC -MS. In all three samples, geraniol (67.6 -83.6%) was the major constituent and, although the composition of the three oils was similar, quantitative differences in the concentration of some constituents were observed. The GC and GC -MS analysis of the Hyderabad, Lucknow and Amarawati oils resulted in the identification of 40, 38 and 33 constituents, representing 98.5%, 99.7% and 99.8% of the oils,respectively. Among the three oils analysed, Amarawati oil was of the highest quality due to higher geraniol (83.6%) and lower geranyl acetate (2.3%) and geranial (1.0%) content. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we present a fairly rigorous analysis of a helically inner-cladded annular step-index waveguide. Using the sheath-helix boundary conditions on the inner core-cladding boundary and simple step-index boundary conditions on the outer core-cladding boundary, the modal characteristic equation of the waveguide is derived by taking a vector approach and dispersion curves are drawn. We observe the effect of the pitch angle of the helical windings on the modal dispersion characteristics of the proposed waveguide. The main feature of the waveguide is the occurrence of negative dispersion and band gap. This property may be attributed to the periodicity of the inner helical cladding. The width of the forbidden region increases with the pitch angle and thereafter at the pitch angle ≈90° the region is not found. It is also observed that the lowest cutoff value for the usual curves slightly decreases with the increase in the pitch angle. Thus the pitch angle acts as the controlling factor for the negative dispersion and photonic band gap. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 69–74, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10828 [ABSTRACT FROM AUTHOR]

This paper presents a comparative study of dispersion characteristics of metal-clad waveguides with concave-lens-like cross sections. Using the point-matching method under weak-guidance approximation, the modal characteristic equation is derived and the modal dispersion curves are obtained. The proposed waveguide may be conceived as a distortion of the square waveguide with a transverse compression at one pair of its parallel sides in order to become concave lens shaped. We find that, the effect of the concave lens shaped distortion is to shift the lowest cutoff value (Vc) towards a larger V value, and increases the number of modes. It is also observed that the lowest cutoff value increases gradually with the increase in the compression depth. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 388–392, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10772 [ABSTRACT FROM AUTHOR]

In this paper, we present a comparative study of different types of concave lens-shaped dielectric waveguides and a dielectric square waveguide. Using the point-matching technique under the weak-guidance approximation, a general characteristic equation has been derived and modal dispersion curves are obtained and interpreted. This waveguide cross section may be considered as a distortion of the square waveguide with a transverse compression at one pair of parallel sides in order to form the concave lens shape. Some important insights have been drawn about the comparison of their dispersion curves. It is observed that the cutoff value of the lowest order mode (Vc) increases with an increase in compression depth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 337–342, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10600 [ABSTRACT FROM AUTHOR]

Using a fairly rigorous analysis, a general characteristic equation for an annular step-index fiber with helical windings on the core-cladding boundaries was derived. We present the modal dispersion characteristics for some lower-order modes of this dielectric waveguide. We also use the variation of helix pitch angles of the windings and discuss their effect on the dispersion curves of the proposed waveguide. An important property, the presence of band gap, was found for some particular combinations of pitch angles. This may be attributed to the periodicity of the helical structure. We can say that pitch angle acts as a controlling factor for the propagation modes. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 338–344, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10315 [ABSTRACT FROM AUTHOR]

In this communication, we present a comparative study of different types of dielectric trapezoidal waveguides. Using a numerical method, we obtain the modal characteristic equations of these trapezoidal waveguides. The modal characteristic equations are obtained in this case by using a point-matching method under the weak guidance approximation. Dispersion curves are also obtained. The modal characteristics of trapezoidal waveguides are compared with those of square waveguides in detail. Some important insights have been obtained, which are distortions of a square shape into a trapezoidal shape responsible for the slight increase in the lowest cutoff value (Vc); the distortion from a square shape to a trapezoidal shape is also responsible for the increase in the number of modes. This study can be viewed as a tolerance study of the waveguide with the square cross section under a trapezoidal distortion. ©2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 461–464, 2002. [ABSTRACT FROM AUTHOR]

Eight- to ten-year old French hybrid Vidal 256 grapevines in southern Maryland produced berries about one-third normal size but did not express any obvious leaf symptoms. Electron microscopy of negatively stained tissue-dip preparations and sectioned material from such vines showed individual and membrane-associated 28 nm spherical virus-like particles and closterovirus- like particles. The spherical particles were characterized as an isolate of tomato ringspot virus (TomRSV-G) that infected a wide range of herbaceous hosts by mechanical inoculation, but did not infect tomato, bean or petunia plants susceptible to the type strain of TomRSV. The closterovirus-like particles did not react, by immunosorbent electron microscopy, with antisera to grapevine virus A (grapevine stem-pitting associated virus of Conti et al. 1980) or the 2200 nm Swiss grapevine leaf roll closterovirus (GuGLERI et al. 1984). [ABSTRACT FROM AUTHOR]

Arginase (EC 3.5.3.1) activity increased in the cotyledon, while it declined rapidly in the embryonic axis of Bengal gram (Cicer arietinum L. cv. Desi type) seeds during germination. The decrease in enzyme activity in the embryonic axis was accompanied by changes in the properties of arginase in vitro such as decreased stability, increased heat lability and failure to bind to DEAE-cellulose. These alterations were due to the presence of a low-molecular-weight factor in the extract, which was purified and identified as a hexose derivative. During germination the concentration of the factor increased in the embryonic axis, while no detectable level of the factor was present in the cotyledons. We postulate that the factor may have a role in the regulation of arginase activity in vivo. [ABSTRACT FROM AUTHOR]