GaAs Clusters in the Quantum Size Regime: Growth on High Surface Area Silica by Molecular Beam Epitaxy

Molecular beam epitaxy has been used to grow microcrystalline clusters of gallium arsenide (GaAs) in the size range from 2.5 to 60 nanometers on high-purity, amorphous silica supports. High-resolution transmission electron microscopy reveals that clusters as small as 3.5 nanometers have good crystalline order with a lattice constant equal to that of bulk GaAs. Study of the microcrystallite surfaces by x-ray photoelectron spectroscopy shows that they are covered with a shell (1.0 to 1.5 nanometers thick) of native oxides of gallium and arsenic (Ga(2)O(3) and As(2)O(3)), whose presence could explain the low luminescence efficiency of the clusters. Optical absorption spectra of the supported GaAs are consistent with the blue-shifted band edge expected for semiconductor microcrystallites in the quantum size regime.     

Biochemical Composition of Pulp and Seed of Wild Jack (Artocarpus hirsutus Lam.) Fruit

Plant Foods for Human Nutrition - Wild jack (Artocarpus hirsutus Lam.) is an endemic perennial tree of Western Ghats of India. Wild jack, a timber purpose tree, is distributed in several Kaan...     

Chemical analysis and nutritional assessment of Teramnus labialis (L.) Spreng. (Fabaceae)

Seeds of Teramnus labialis (L.) Spreng.(Fabaceae), used as food by Malayali tribals in theKollihills of Salem District, Tamil Nadu in SouthIndia, were investigated for their nutritional value. These seeds were analyzed for proximate composition,total (true) seed proteins, seed proteinfractions, amino acid composition, fatty acidcomposition, minerals and antinutritional factors. Crude protein, crude fat, ash, and nitrogen freeextracts constituted 22.86%, 6.10%, 4.62%, and,58.15%, respectively, of the seed weight. The caloricvalue of 100 g dry matter of seed material was 378.94kcal. The essential amino acids lysine, leucine +isoleucine, arginine, valine and histidine werepresent in relatively large quantities. Theunsaturated fatty acids constituted more than 60% ofthe crude fat. Concentrations of minerals such aspotassium, magnesium, calcium, and, phosphorus werehigh. Antinutritional factors such as total freephenols, tannins, L-DOPA, hydrogen cyanide andphytic acid were present in minute quantities. Theseantinutritional factors are potentially eliminated using the conventional method of soaking the seeds in water,boiling with water and decanting prior to consumption.     

Soil–plant–animal continuum in relation to macro and micro mineral status of dairy cattle in subtropical hill agro ecosystem

The purpose of the present study was to study the soil–plant–animal continuum in subtropical hilly areas. Soil (n?=?96), fodder (n?=?96), and blood serum samples from dairy cattle (n?=?120) were collected from eight districts of Mizoram, a hilly state in India. The samples were digested using diacid mixture (HNO₃:HClO₄; 10:4) and analyzed for macro (Ca, P, Mg, Na, and K) and micro (Cu, Co, Mn, Fe, and Zn) mineral concentrations. The macro and micro mineral concentrations varied among the different districts. The correlation values between fodder and cattle were significant for all the minerals studied except for P and K. The correlation value between fodder and cattle was highly significant (P?<?0.01) for Ca (0.878), Mg (0.88), Cu (0.885), and Zn (0.928). However, such correlations were not observed between the mineral levels in cattle and mineral levels in soil except for Ca (0.782). Equations developed in the present study for prediction of Ca (R ²?=?0.797), Mg (R ²?=?0.777), Zn (R ²?=?0.937), Fe (R ²?=?0.861), and Cu (R ²?=?0.794) had significant R ² values. Further, it is inferred that dairy cattle reared under smallholder production system were deficient in most of the minerals and supplementation of required minerals is essential for optimum production.     

Development of NILs from heterogeneous inbred families for validating the rust resistance QTL in peanut (Arachis hypogaea L.)

Heterogeneous inbred families segregating for rust resistance were identified from the two crosses involving susceptible (TAG 24 and TG 26) and resistant (GPBD 4) varieties of peanut. Rust‐resistant (less than score 5) and rust‐susceptible (more than score 5) plants were identified in each HIF and evaluated under rust epiphytotic conditions. The set of plants belonging to the same HIF, but differing significantly in rust resistance, not in other morphological and productivity traits, was regarded as near‐isogenic lines (NILs). Largely, rust‐resistant NILs had GPBD 4‐type allele, and susceptible NILs carried either TAG 24 or TG 26‐type allele at the three SSR loci (IPAHM103, GM1536 and GM2301) linked to a major genomic region governing rust resistance. Comparison of the remaining genomic regions between the NILs originating from each of the HIFs using transposon markers indicated a considerably high similarity of 86.4% and 83.1% in TAG 24 × GPPBD 4 and TG 26 × GPBD 4, respectively. These NILs are useful for fine mapping and expression analysis of rust resistance.     

Evaluation of somaclonal variation for genetic improvement of patchouli (<Emphasis Type="Italic">Pogostemon patchouli</Emphasis>), an exclusively vegetatively propagated aromatic plant

Patchouli (Pogostemon patchouli) is an important, exclusively vegetatively propagated aromatic plant, whose essential oil is widely used in perfumery and cosmetic products. Forty SC1 generation (first generation following in vitro phase) somaclones selected randomly from about 400 somaclones developed from the variety Johore, were multiplied through stem cuttings and evaluated in SC₂ and SC₃ generations to study the extent of somaclonal variation generated for plant height, herb yield, essential oil content, essential oil yield, and seven constituents of the essential oil. Significant or highly significant somaclonal variation was observed for plant height, herb yield, essential oil content, essential oil yield, and contents of patchouli alcohol, α-guaiene, α,δ-patchoulene, and α-bulnesene in the essential oil. The number of somaclones significantly superior to the parental variety for plant height, herb yield, essential oil content, and patchouli alcohol content in the essential oil ranged from 8–16 and the maximum superiority over the parental variety for these traits ranged from 21–79%. Broad-sense heritability estimates of plant height, herb yield, and essential oil content were 0.60–0.70 while those of essential oil yield and patchouli alcohol content were 0.44 and 0.47, respectively. Heritability estimates of other studied essential oil constituents were generally low (0.12–0.38). A high positive correlation was observed between essential oil yield and herb yield suggesting that selection for herb yield would be effective in improving essential oil yield. Patchouli alcohol content in the essential oil was negatively correlated with all the studied traits. Somaclonal variation, heritabilities of traits, and inter-trait correlations are reported for the first time in patchouli.     

Influence of plant growth stage on the essential oil content and composition in Davana (Artemisia pallens wall.)

The influence of three plant growth stages (full emergence of flower heads, anthesis, and initiation of seed set) on the essential oil content and composition in Davana (Artemisia pallens Wall) was investigated over two successive seasons. The essential oil content was found to be higher at the full emergence of flower heads than at anthesis and initiation of seed set stages. The contents of davanone, the major constituent of davana oil, and linalool decreased while those of (Z)- and (E)-methyl cinnamate, (E)-ethyl cinnamate, bicyclogermacrene, davana ether, 2-hydroxyisodavanone, and farnesol increased from flower heads emergence stage to the initiation of seed set stage. These results support the general practice of harvesting the crop at full bloom stage. Five compounds, viz., (Z)- and (E)-methyl cinnamates, (Z)- and (E)-ethyl cinnamates, and geranyl acetate, were identified for the first time in davana oil.     

Antibacterial activity of Urena lobata root.

The methanol extract of Urena lobata root showed a broad spectrum of antibacterial activity.     

Chlorophyll Dynamics in Rice (Oryza sativa) Before and After Flowering Based on SPAD (Chlorophyll) Meter Monitoring and its Relation with Grain Yield

The rice plant at any point in time is composed of leaves of physiologically different ages, so it follows that the leaves differ in their contributions to the growth of the whole plant and its grain yield. As the leaf chlorophyll content (Soil Plant Analytical Division value) is the best indicator of photosynthetic activity in rice, the chlorophyll content of rice before and after flowering was determined in a weed management field experiment on direct wet seeded rice. The results indicated that the leaf chlorophyll content at 79 days after sowing correlated well with the grain yield of rice. Multiple regression models also indicated the dependence of rice yield on leaf chlorophyll content before and after flowering.