查看更多>>摘要：? 2022 Elsevier B.V.Shape memory polyurethane (SMPU) has been widely recognized as promising potential smart materials. While, porous SMPU presented imperfect shape memory and mechanical properties. In this work, nanocellulose was incorporated in SMPU to improve the comprehensive properties of the porous SMPU by 3D printing prototyping. The shape fixation ratio (Rf) and the shape recovery rate (Rr) were improved to above 99.0%, with adding appropriate proportion of cellulose nanocrystals (CNCs) and ball milled nanocellulose (BMC). And the highest tensile strength of the 3D printed SMP composite was 12.05 MPa, which was 71% higher than pure PU (7.02 MPa), more importantly, these composites have tunable glass transition temperature (Tg), that is to say, when under the appropriate preparation, the composites with Tg close to human body temperature can be obtained, which enables the potential applications in smart biomaterials.
查看更多>>摘要：? 2022 Elsevier B.V.The purpose of this study was to establish a jujube (Zizyphus jujuba Mill.)–cotton (Gossypium hirsutum Linn.) intercropping agroforestry system in the south and north of Xinjiang Uygur Autonomous Region and to determine the impact of intercropping systems on microclimate, yield, and income compared with sole-cropping planting. Therefore, a two-year field experiment was carried out in the Hotan and Shihezi areas to measure photosynthetically active radiation (PAR) on the space-time scale, air temperature on the time scale, wind speed and windproof efficiency on the time scale, and yield and income. Through correlation analysis, the relationship between intercropping microclimate and intercropping yield were revealed. Compared with corresponding sole-cropping cotton, the PAR of intercropping in Hotan and Shihezi was 13.04% and 12.75% lower, respectively, and the closer to the tree alley, the smaller it was. Intercropping changed the daily dynamics of air temperature, especially at high temperatures, under which the decrease range was significant. Intercropping has buffer effect and latent heat release on air temperature and the maximum temperature in Hotan and Shihezi intercropping was 13.57% and 6.49 lower than that in sole-cropping, respectively. Intercropping reduced the wind speed, the greater the wind speed in a certain range, the stronger the windproof efficiency. The maximum windproof efficiency of Hotan intercropping was 50.92%, and that of Shihezi was 48.56%. The intercropping system had advantages in land equivalent ratio (LER), yield, and income. The income of intercropping was 11622.38–12528.55 USD·hm?2, 55.41–61.91% higher than that of sole-cropping cotton and 19.19–20.37% higher than that of sole-cropping jujube. The results showed that the development of jujube-cotton intercropping could protect the growing environment of cotton and increase farmers' economic income by improving the field microclimate.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, the chemical profile of the leaf essential oil of hitherto uninvestigated shrub Clausena austroindica B.C.Stone & K.K.N.Nair and its insecticidal potential against two stored product pests, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) are being investigated. Essential oils from the leaves of C. austroindica collected from two locations in south India were isolated by hydrodistillation and analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Six to eight compounds comprising 99.41–99.44% were characterized with trans-anethole (phenyl propanoid) as the major component (95.12–97.44%) in leaf essential oils. Trans-anethole was isolated from the leaf oil by column chromatography, characterized by Fourier Transform Infrared (FT-IR), ultraviolet-visible (UV-Vis), 1H-, 13C- and distortionless enhancement by polarization transfer (DEPT 135) nuclear magnetic resonance (NMR) spectroscopy, and quantified by external standardization. Insecticidal activity of C. austroindica leaf oil and trans-anethole were assessed against the rice weevil (S. oryzae) and red flour beetle (T. castaneum) by contact and fumigant toxicity assays. Mammalian cell toxicity of C. austroindica leaf oil and trans-anethole was also tested against L929 cell lines using (3-(4,5-dimethylthiazol-2-yl)?2,5-diphenyltetrazolium bromide) MTT assay and quantification of reactive oxygen species (ROS). C. austroindica leaf oil and trans-anethole demonstrated superior contact and fumigant toxicities against adult beetles of S. oryzae and T. castaneum. C. austroindica leaf oil and trans-anethole showed potential fumigant toxicity against S. oryzae (lethal concentration 50 (LC50) 38.80 & 76.98 μL/L) and T. castaneum (LC50 35.65 & 29.10 μL/L). Relatively less prominent viz., S. oryzae: LC50 leaf oil 469.70 μL/L, trans-anethole 2543.20 μL/L; T. castaneum: LC50 leaf oil, 1090.70 μL/L, trans-anethole 2050.84 μL/L, but significant contact toxicities were displayed by the leaf oil and trans-anethole against the two stored product pests. Both C. austroindica leaf oil and trans-anethole (< 2.0 μg/mL) have not demonstrated any mammalian cell (L929 cell line) toxicity. Our study demonstrates the potential of C. austroindica leaf essential oil as a new botanical insecticide for controlling stored product pests. Its major component, trans-anethole, also showed prominent insecticidal activity.
查看更多>>摘要：? 2022 Elsevier B.V.Sandalwood (Santalum album L.) is a hemiparasite unable to absorb the required nutrients directly from the soil. Therefore, it needs a suitable host for successful cultivation. The effect of hosts on the growth and development of sandalwood was studied in an eleven-year-old plantation in the Northern dry zone of Karnataka. The sandalwood trees grown with Prosopis (Prosopis juliflora L.) exhibited better growth in terms of tree height (6.58 m), canopy spread (4.64 m), canopy volume (48.60 m3), stem girth (40.70 cm), main stem volume (36.79 dm3) and its annual increment (16.39%). They were also summer hardy and recorded higher chlorophyll, free proline, and soluble sugar in leaves. The summer leafiness of sandalwood was associated with the free proline content in its leaf (r = 0.927), which was in turn correlated with the free proline content in leaves of their respective hosts (r = 0.899). The sandalwood trees with Prosopis also exhibited signs of early heartwood development, thus making Prosopis a suitable host for the commercial cultivation of sandalwood in hot semi-arid conditions.
查看更多>>摘要：? 2022 Elsevier B.V.To discover non-food bioactive natural-product-based pesticides for crop protection, new osthole esters ((2′E)? 4′-(isoxazolin-5''-yl)carbonyloxyosthole derivatives) containing the isoxazoline fragment were constructed by structural modification of a natural coumarin osthole isolated from Cnidium monnieri. The configurations of three compounds were confirmed by X-ray crystallography. Their agricultural activities were evaluated against two typically crop-threatening pests Mythimna separata Walker and Tetranychus cinnabarinus Boisduval. Against T. cinnabarinus, compounds 4 (LC50: 0.75 mg/mL) and 5h (LC50: 0.76 mg/mL) displayed ≥ 1.5-fold acaricidal activity of osthole and good control effects in the greenhouse. Against M. separata, compounds 5a (final mortality rate (FMR): 55.1%), 5c (FMR: 62.0%), and 5o (FMR: 55.1%) at 1 mg/mL showed 1.5–1.6 folds growth inhibitory activity of osthole. It suggested that introduction of the acryloyloxy group at the C-4′ position of osthole was important for insecticidal and acaricidal activities, and compound 4 can be further structurally modified as pesticidal agents.
NSTL
Elsevier