The onset of AlN nucleation on Si(111) and Si(110) surfaces during gas source molecular beam epitaxy with ammonia was carried out by reflection high energy electron diffraction. Exposing the clean Si surfaces to NH3 flux at 600 °C yields the formation of crystalline Si3N4 on both (111) and (110) surfaces. An 8×8 Si3N4 structure was observed for the Si(111) surface. On the Si(110) surface a 2.87 Å periodic structure was observed for electron beam directed along [001] azimuth and 2.46 Å periodic structure for the [1¯12] azimuth. Together, these periodic structures confirm the formation of Si3N4 (0001) plane on both Si(111) and Si(110) surfaces.

Hexagonal boron nitride (h-BN) has emerged as an important extreme bandgap semiconductor as well as a two-dimensional material. Achieving the ability for tuning the optoelectronic properties through alloying and heterojunction will further expand the applications of h-BN. By utilizing h-BN epilayer as a template, the synthesis of BN-rich B 1−x Ga x N alloys and quantum wells crystalized in the hexagonal phase has been demonstrated for the first time by metal organic chemical vapor deposition. The incorporation of Ga tends to enhance the conductivity. A blue shift in the band-edge emission upon the formation of h-BN/BGaN/BN QW has been observed, indicating the feasibility for heterojunction formation.

Xeromphis uliginosa Retz. is an indigenous plant of Bangladesh. Traditionally this plant is used to treat many diseases. In order to explore the medicinal quality of this plant systematically, the crude methanol extract of roots was screened for antidiabetic activity in rats model. The antidiabetic action was determined by using oral glucose tolerance test (OGTT) and alloxan induced antidiabetic test. In OGTT, both doses (200 and 400 mg/kg body weight) of methanol extract reduced the blood glucose significantly (p < 0.05) after 1 h on administration and continued to remain lower up to 3 h. However, the extract significantly (p < 0.05) attenuated the blood glucose level in diabetic rats at a dose of 500 mg/kg body weight which was comparable to the standard drug used (glibenclamide).

This study highlighted the structure, species composition and biomass carbon stock in the Abies Pindrow dominant community in Dir Kohistan, temperate region of Pakistan. The results showed that stem density varied between 3 ha -1 in Acer ceasium to 273 ha -1 in Abies pindrow, with a total stand density of 350 trees ha -1 . The importance value index (IVI) varied between 2.27 (Acer ceasium) and 62.22 (Abies pindrow). The mean basal area was recorded at 132.15 m 2 ha -1 . The average stem volume was measured at 120 m 3 ha -1. The mean stem and total tree biomass carbon was 639 and 967 t ha -1 respectively. Similarly, the understory vegetation and litter, dead wood and cone biomass carbon was found 1.43 t ha -1 and 12.02 t ha -1 respectively. Soil carbon (0-30 cm) was calculated by using Walkey-Black methods multiplied by mean soil bulk density measurements. The average soil organic carbon was calculated 70.75 t ha -1 . The Total average carbon stock of the community was calculated at 568.63 t ha -1 . These results provide the evidence that, Abies Pindrow dominant community has a greater potential of sequestering carbon. Upon proper carbon management the ecosystem might be included in the carbon trading of Kyoto protocol.

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