MONOCOT POLLEN FLORA OF PASCHIM MEDINIPUR DISTRICT, WEST BENGAL WITH A NOTE ON POLLEN DISPERSAL MECHANISM

During the present investigation pollen morphological studies of 66 species belonging to 19 families of monocots in Paschim Medinipur district have been worked out by light microscopy. The studied families are Agavaceae, Amaryllidaceae, Arecaceae, Asphodelaceae, Cannaceae, Colchicaceae, Commelinaceae, Costaceae, Cyperaceae, Hemerocallidaceae, Hydrocharitaceae, Iridaceae, Liliaceae, Limnocharitaceae, Musaceae, Poaceae, Pontederiaceae, Typhaceae and Zingiberaceae. The apertural patterns are mostly belong to two different categories viz. monosulcate form (Agavaceae, Amaryllidaceae, Arecaceae, Asphodelaceae, Colchicaceae, Commelinaceae, Costaceae, Hemerocallidaceae, Hydrocharitaceae, Iridaceae, Liliaceae, Limnocharitaceae, Musaceae, Poaceae, Pontederiaceae) and anaporate type (Cyperaceae, Poaceae and Typhaceae). The shape of the pollen grains with monosulcate apertures are mostly oblate to peroblate type whereas taxa showing anaporate apertures are more or less spheroidal. Regarding the mode of pollen dispersal plant taxa with monosulcate apertures and apiculate surface ornamentations (e.g., reticulate, rugulate, spinulate, verrucate) are entomophilous (mainly melittophilous) whilest anaporate with smooth or minutely apiculate surface features are anemophilous. Here, entomophilous taxa provide rewards as pollen grains and nectar to the honeybee speecies, therefore, contribute as resource mobilizer for sustainance of honeybee colonies.Â

In situ electron beam irradiated rapid growth of bismuth nanoparticles in bismuth-based glass dielectrics at room temperature

In this study, in situ control growth of bismuth nanoparticles (Bi(0) NPs) was demonstrated in bismuth-based glass dielectrics under an electron beam (EB) irradiation at room temperature. The effects of EB irradiation were investigated in situ using transmission electron microscopy (TEM), selected-area electron diffraction and high-resolution transmission electron microscopy. The EB irradiation for 2-8 min enhanced the construction of bismuth nanoparticles with a rhombohedral structure and diameter of 4-9 nm. The average particle size was found to increase with the irradiation time. Bismuth metal has a melting point of 271 A degrees C and this low melting temperature makes easy the progress of energy induced structural changes during in situ TEM observations. This is a very useful technique in nano-patterning for integrated optics and other applications

Single-Step Synthesis and Surface Plasmons of Bismuth-Coated Spherical to Hexagonal Silver Nanoparticles in Dichroic Ag:Bismuth Glass Nanocomposites

Here, we report for the first time the synthesis of bismuth-coated silver nanoparticles in dichroic bismuth glass nanocomposites by a novel and simple one-step melt quench technique without using any external reducing agent. The metallic silver nanoparticles (Ag NPs) were generated first, and subsequently, metallic bismuth was deposited on the Ag NPs and formed a thick layer. The reduction of Bi(3+) to Bi(o) and subsequently its deposition on the Ag NPs (which were formed earlier than Bi(o)) in the K(2)O-Bi(2)O(3)-B(2)O(3) (KBB) glass system have been explained by their standard reduction potentials. The UV-vis absorption spectra show a prominent surface plasmon resonance (SPR) absorption band at 575 nm at lower concentrations (up to 0.01 wt%); three bands at 569, 624 and 780 nm at medium concentration (0.02-0.03 wt%); and two weak bands at 619 and 817 nm at highest concentration (0.06 wt%) of silver. They have been explained by the electrodynamics theories. TEM images reveal the conversion of spheroidal (5-15 nm) to hexagonal (10-35 nm) shaped Ag NPs with the increase in concentration of silver (up to 0.06 wt%). SAED pattern confirms the crystalline planes of rhombohedral bismuth and cubic silver. Thermal treatment at 360 A degrees C, which is the glass transformation temperature (T (g)) of the sample containing lower concentration of silver (0.007 wt%), shows red-shifted SPR band due to increase in size of NPs. Whereas the sample containing higher concentration (0.06 wt%) of silver under similar treatment exhibited changes in SPR spectral profile happened due to conversion to spherical NPs from hexagonal shape and reduction in size (10-20 nm) of NPs after heat treatment for 65 h. HRTEM images corroborate the different orientations of the NPs. FESEM images reveal hexagonal disk like structure having different orientations. Dichroic nature of the nanocomposites has been explained with the size and shape of Ag nanoparticles. We believe that this work will create new avenues in the area of nanometal-glass hybrid nanocomposites and the materials have significant applications in the field of optoelectronics and nanophotonics

Studies on the effect of sodium arsenate & cadmium chloride on Pithophora oedogonia (Mont.) Wittrock 1877

Cadmium and Arsenic are heavy metals although not common in our environment, its threat in certain places are aggravated due to anthropogenic factors. To know its critical role on plants the investigation was made using Na2HAsO4 and CdCl2 treatment on Pithophora oedogonia (Mont.) Wittrock 1877. The observations were made after 14 days of treatment. The changes were noted. In both cases, the treated cells exhibited gradual disruption of cell wall and cell membrane. The chlorophyll content initially increased and finally decreased due to the notable destruction of chloroplasts in both treated cells. A profuse number of akinetes were observed at 100 ppm and 150 ppm of Na2HAsO4 and CdCl2 treated media. Decrease in protein content was started at 100 ppm in both cases. The lipid content initially decreased at 50 ppm and at 100 ppm lipid profile increased in terms of toleration to the Na2HAsO4 and CdCl2 stress. Pithophora oedogonia (Mont.) Wittrock 1877 exhibited more sensitivity to CdCl2 stress & showing abrupt changes in chlorophyll-a and chlorophyll-b production. The carotenoid production shown more sensitivity in Na2HAsO4 stress. Total phenol production was decreased initially and at 200 ppm CdCl2 stress had shown significant enhancement than the control set but at the 200 ppm of Na2HAsO4 shown inhibitory effect

A Method for Determination of Protein Concentration in a Given Unknown Sample Using Absorbance Difference Between 205 nm and 280 nm

Nowadays, determining the protein content of a sample is a common experiment that is conducted in laboratories. Although there are several ways to measure protein content, dye-based spectrophotometric methods are most frequently used in laboratories. In dye-based approaches, protein assays are mostly carried out at a certain wavelength. Protein concentration tests like Lowry’s take a long time; whereas Bradford’s is quick but requires expensive chemicals. In order to reduce the usage of time and money associated with protein assay, we first looked into and then proposed an easy, affordable, and more accurate technique of determining protein concentration that uses standard curves but doesn’t use any dyes. The difference of two UV wavelength absorbance values at 205 nm and 280 nm was used to determine the protein concentration where one absorbance was recorded for the presence of peptide bonds and another for aromatic proteins. The proposed method has many advantages as it consumes minimum time and chemicals but the major setback is anionic detergents, which can shift the absorbance spectra abruptly

Photoluminescence enhancement of Eu(3+) by energy transfer from Bi(2+) to Eu(3+) in bismuth glass nanocomposites

Bi(2+)-enhanced photoluminescence of Eu(3+) doped Bi(0)-bismuth glass nanocomposites are demonstrated here. The generation of bismuth nanoparticles (NPs) and its typical surface plasmon resonance at 460 nm are controlled by the oxidative method instead of the conventional reduction technique during melt-quench processing. TEM images evidence the presence of spherical Bi(0) NPs of 10-15 nm sizes and SAED pattern reveals their crystalline rhombohedral phase formation. The enhanced photoluminescence of Eu(3+) is found to occur at 613 and 703 nm due to (5)D(0 ->)(7)F(2) and (5)D(0)->(7)F(4) transitions respectively. We believe that it has happened due to energy transfer from Bi(2+) to Eu(3+)

Controlled oxidative synthesis of Bi nanoparticles and emission centers in bismuth glass nanocomposites for photonic application

Here we demonstrate an oxidative process to control metallic bismuth (Bi(0)) nanoparticles (NPs) creation in bismuth glass nanocomposites by using K(2)S(2)O(8) as oxidant and enhanced transparency of bismuth glasses. Formation of Bi(0) NPs has been monitored by their distinct surface plasmon resonance (SPR) band at 460 nm in the UV-visible absorption spectra. It is further confirmed by the transmission electron microscopy (TEM) images which disclose the formation of spherical Bi(0) NPs whereas the selected area electron diffraction (SAED) pattern reveals their crystalline rhombohedral phase. These glasses are found to exhibit visible and near infrared (NIR) luminescence bands at 630 and 843 nm respectively on excitation at 460 nm of the SPR band. It is realized that the luminescence center of bismuth species is an uncertain issue, however, it is reasonable to consider that the emission band at 630 nm is due to the combination of (2)D(5/2) -> (4)S(3/2) of Bi(0) and (2)P(3/2) (1) -> (2)P(1/2) of Bi(2+) transitions, and that of NIR emission band at 843 nm is attributed to the (2)D(3/2) -> (4)S(3/2) of Bi(0) transition. (C) 2011 Elsevier B.V. All rights reserved

Resolving Power of Optical Instruments Using Finite Element Method

The provided simulation takes in various tasks in various parameters to calculate the resolving power of the optical instruments and also conveniently simulates their behavior. To calculate the resolving power of the optical instruments such as prism,telescope or microscope a special technique known as “FINITE ELEMENT METHOD” has been used. Basically in this method the convex lens is divided into several segments and resolving power of each segment is computed separately, details of which is provided in the concerned topic. Finally a software model has been developed for prism, single convex lens and combination of lenses to study and show the required behavior. This software model is developed using Visual C++

Determination of Nectar Resources through Body Surface Pollen Analysis: A Study with the Stingless Bee Tetragonula iridipennis Smith (Apidae: Meliponini) in West Bengal, India

Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is difficult in cavity-nesting natural stingless bee colonies. Furthermore, it is detrimental to the wild bee’s colony and may threaten their survivability. We analyzed adhered body surface pollen of incoming nectar foragers (which were smeared incidentally during nectar foraging) as an alternative method to determine nectariferous flora of Tetragonula iridipennis in West Bengal, India. By this method, we have identified 75 pollen types. The number of obtained pollen types was lower in the human-altered habitats of Midnapore city (44 pollen types) than the semi-natural habitats of Garhbeta (71 pollen types). Excluding a few pollen types of non-nectariferous plants, most of the pollen types came from nectariferous plants of both crop and non-crop species. Non-crop flowering plants (viz. Ailanthus excelsa, Borassus flabellifer, Eucalyptus tereticornis, Lannea coromandelica, Peltophorum pterocarpum, and Tectona grandis) provided a significant amount of nectar to the bee species and, therefore, play an important role in the conservation of the bee species

Effects of TiO(2)-SiO(2) fillers on thermal and dielectric properties of bismuth glass microcomposite dielectrics for plasma display panel

The combined effects of TiO(2) and SiO(2) fillers on thermal and dielectric properties of new lead-free environmental friendly zinc bismuth borate, ZnO-Bi(2)O(3)-B(2)O(3) (ZBIB) glass microcomposite dielectrics have been investigated from the viewpoint of application as rear glass dielectric layer of plasma display panels (PDPs). The interaction of fillers with glass occurred during firing has also been explored by XRD, SEM and FTIR spectroscopic analyses. All the properties are found to be regulated by the covalent character (a fundamental property) of resultant microcomposite dielectrics. In this work, the co-addition of TiO(2)-SiO(2) filler to ZBIB glass is found to be more effective to adjust the required properties to employ with PD200 glass substrate in PDP technology