Darrang College

Urban street trees are a key component of green infrastructure, yet how road typology influences their diversity, structure, and composition remains poorly understood in rapidly urbanizing Indian cities. We quantified street-tree composition, abundance, and health across four road categories in southern Guwahati, northeast India, using a spatially stratified survey of 143 roadside transects (200 m each). We tested whether street-tree composition and structure differed among road types, and whether contemporary planting and management practices were associated with compositional simplification. A total of 1,455 trees representing 80 species and 29 families were recorded. Species richness and Shannon diversity were highest along large roads and lowest along highways. Species composition differed significantly among road categories, although road type explained only a modest proportion of the variation. Five species collectively accounted for approximately 45% of all individuals, indicating strong compositional dominance. Mean diameter at breast height (DBH) was 21.9 ± 22.3 cm, and mean health scores indicated generally good tree condition. Tree diameter and health differed significantly among road categories, and native species comprised approximately 70% of all recorded individuals. Size-class distributions revealed a predominance of younger trees, indicating recent planting efforts and increasing reliance on smaller ornamental species. Our findings provide the first quantitative baseline of street-tree assemblages in Guwahati and demonstrate that road typology is associated with differences in urban forest composition and structure. Diversifying planting programmes, conserving mature canopy trees, and adopting road-specific greening strategies will be essential for enhancing ecological resilience in rapidly urbanizing cities.

The process of water treatment is aimed at reducing or removing contaminants either chemical or biological in water for its utilization in safe drinking or any other essential purposes. Polymer nanocomposites that show responsiveness to external stimulants play a vital role in this process and purify water by actuating stimuli and by reviving the polymers successively. In response to environmental changes, these polymer nanocomposites can firmly undergo physical as well as chemical characteristic changes like shrinkage, and expansion, or show alterations in optical and electrical features on the basis of the induced stimulants. So far, numerous polymeric compounds that are sensitive to light, heat, CO2, etc. including prefabricated nano polymers, nanoparticles, etc. have been employed in water treatment. This book chapter emphasizes the efficacy of different smart polymeric nanocomposites in removing harmful pollutants including toxic ions, water-soluble ions, and harmful organic colorants in the water treatment process.

Ethnopharmacological relevance: Persicaria hydropiper is a medicinal herb that also holds significant culinary value in Southeast Asia. Among the Mishing tribe of Assam, the roots of this plant are traditionally used for female contraception. Aim of the study: The present study aimed to evaluate the potential toxicological effects of the methanolic root extract of P. hydropiper, which was administered to female mice to prevent conception. Materials and Methods: The assessment included acute toxicity tests, behavioural studies, biochemical analyses (SGOT and SGPT levels), histological examinations of the liver and kidney and genotoxicity tests using micronucleus assays. Results: No notable signs of acute or behavioural toxicity were observed in extract-treated mice. In fact, treated groups exhibited central nervous system stimulating and anxiolytic effects at a dose of 1000 mg/kg body weight. A significant increase in locomotor activity was recorded on Day 1, Day 5, Day 6 and in ovariectomized (OVX) mice (81.7±0.40, 80.8±0.72, 82.0±0.26 and 80.3±0.15 cases/5 min, respectively), along with higher head-dip counts on Day 1, Day 4, Day 5 and Day 6 (34.5±0.43, 35.1±0.28, 35.0±0.26 and 33.6±1.45, respectively). Histological sections of liver and kidney tissues revealed nearly normal structures. Genotoxicity evaluations showed no significant variation in micronucleus frequency. However, a marked increase in SGOT was detected in ovariectomized females (123.65±2.86 IU/l), while SGPT levels rose in the Day 1, 2, 3 and 6 treated groups (52.52±1.81, 52.01±1.95, 54.84±2.00 and 49.37±1.78, respectively), suggesting mild hepatotoxic effects. Conclusion: Studies on the toxicological aspects of any traditional medicine are necessary for the proper formulation of a drug. Most of the parameters selected for toxicity detection showed no significant alteration between the control and treated mice groups. Only mild hepatotoxicity was observed in the extract-treated group of female albino mice. Moreover, some improvements in terms of exploratory behaviour could be observed in the treated groups. Thus, the extract may be considered low or non-toxic at this present dose. Further studies are necessary to investigate toxicological impacts on other tissues and to identify the potentially toxic compounds within the extract, which could aid in the development of antifertility agents derived from this plant.

A Pd(II)-catalyzed cascade annulation of 4-hydroxy-3-maleimidecoumarin with alkynes has been demonstrated. This unique strategy highlights an interesting process for the cascade formation of three rings (three-, five-, and six-membered) of carbocycles and heterocycles through spiro-annulation followed by cyclization. This strategy offers an attractive platform for synthesizing various coumarin-fused complex structures in good yields. Additionally, six synthesized compounds have been unambiguously confirmed by single-crystal X-ray diffraction analysis.

We investigate the consequences of annealing on the structure, microstructure, magnetic, and electrical transport of Mn2Ni1.6Sn0.4 ribbons. The 40-60 mu m thick ribbons were formed by melt spinning of the bulk ingot synthesized by RF induction melting. Ribbons were annealed at 600 degrees C for 12 hrs and the other at 800 degrees C for 2 hrs in vacuum. All ribbons crystallize into a cubic symmetry (space group F (4) over bar 3m). The orthorhombic phase appears as the secondary one. In ribbons annealed at 600 degrees C, the crystallite size decreases from similar to 47 nm to similar to 29 nm, and annealing at 800 degrees C doubles the crystallite size to similar to 96 nm. The least amount of microstrains (17x10(-4)) in the as-synthesized ribbon is consistent with the occurrence of the superlattice peaks (111) and (200). Lower intensities of the superlattice peaks in 600 degrees C and 800 degrees C ribbons are consistent with higher microstrains (25x10(-4) and 24x10(-4)). Hence, a higher degree of Ni-Mn ordering improves magnetic properties in annealed samples. The as-synthesized ribbon has an austenite-phase Curie temperature of T-C(A)similar to 303K, which enhances to T-C(A)similar to 320K and T-C(A)similar to 310K after annealing at 600 degrees C and 800 degrees C. The ribbon annealed at 600 degrees C has the highest saturation moment. All the ribbons show the exchange-bias (EB) effect, and the most pronounced effect is seen in the 800 degrees C annealed ribbon. Microstructure uniformization and relative strengths of the Ni-Mn and Mn-Mn interactions improve the magnetics. Near T-C, MT=(M0TC-T)(beta) is satisfied (beta = 0.31, 0.36, and 0.37, for as-synthesized, 600 degrees C and 800 degrees C annealed ribbons). The low-temperature spontaneous magnetization obeys the Bloch law M(T) = M(0) (1-AT(3/2)), with a deviation in 600 degrees C annealed ribbon due to spin freezing. The rho-T has been fitted in the different temperature ranges using the various combinations in rho T=rho(0)+A(ph)T+BsdT alpha. At T < 85 K, the resistivity of the as-synthesized ribbon follows rho T=rho(0)+BsdT alpha, with alpha approximate to 1.47, while for the 600 degrees C annealed ribbon, alpha approximate to 1.49. The exponent alpha similar to 1.5 supports the existence of the spin glass state in the lower temperature region of as-synthesized and 600 degrees C annealed ribbons. In the high-temperature range, the linear rho-T behavior is described by rho T=rho(0)+A(ph)T and consistent with the electron-phonon scattering.