Stable Isotopes (δ13C and δ15N) and Trace Elements of Invertebrates and Fish from the Coastal Waters of Ha Tinh Province, Central Vietnam.

Stable isotope signatures (δ13C, δ15N) and trace elements (TEs) were analyzed from invertebrates and fish to assess food web structure and the biomagnification or biodilution of Cu, Pb, Cd, Zn, Mn, Cr, Hg and As in coastal waters of Ha Tinh Province, Central Vietnam. δ13C and δ15N values of purported food sources (sediments, phytoplankton, macroalgae, and zooplankton) ranged from -21.24 ± 0.39‰ to -16.72 ± 1.02‰ and from 3.02 ± 0.70‰ to 7.30 ± 0.42‰, respectively. The δ13C and δ15N values in invertebrates and fish ranged from -19.75 ± 0.10‰ to -18.68 ± 0.40‰, and from 7.02 ± 1.21‰ to 9.10 ± 0.29‰. The δ15N values showed that the food web structure could be divided into four trophic levels. The benthic invertebrates had significantly higher concentrations of Cu, Pb, Zn, Cd and As. Hg concentrations tended to accumulate higher in the crabs and fish. The biodilution of Pb, Cd, Zn, Cr was observed throughout the food web, whereas biomagnification was observed for Cr, Mn, and As in bivalves; Cd and Zn in gastropods; Pb, Cd, Zn, and As in crabs; Cd in prawns and Hg in fish.

PMMA Bone Cements Modified with Silane-Treated and PMMA-Grafted Hydroxyapatite Nanocrystals: Preparation and Characterization.

In this study, vinyltrimethoxysilane-treated hydroxyapatite (vHAP) and PMMA-grafted HAP (gHAP) were successfully prepared from original HAP (oHAP). Three kinds of HAP (oHAP, vHAP and g HAP) were used as additives for the preparation of three groups of HAP-modified PMMA bone cements (oHAP-BC, vHAP-BC and gHAP-BC). The setting, bending and compression properties of the bone cements were conducted according to ISO 5833:2002. The obtained results showed that the maximum temperature while curing the HAP-modified bone cements (HAP-BCs) decreased from 64.9 to 60.8 °C and the setting time increased from 8.1 to 14.0 min, respectively, with increasing HAP loading from 0 to 15 wt.%. The vHAP-BC and gHAP-BC groups exhibited higher mechanical properties than the required values in ISO 5833. Electron microscopy images showed that the vHAP and gHAP nanoparticles were dispersed better in the polymerized PMMA matrix than the oHAP nanoparticles. FTIR analysis indicated the polar interaction between the PO4 groups of the HAP nanoparticles and the ester groups of the polymerized PMMA matrix. Thermal gravimetric analysis indicated that mixtures of ZrO2/HAPs were not able to significantly improve the thermal stability of the HAP-BCs. DSC diagrams showed that the incorporation of gHAP to PMMA bone cement with loadings lower than 10 wt.% can increase Tg by about 2.4 °C.

First record of fall armyworm Spodoptera frugiperda (J.E. Smith (Lepidoptera: Noctuidae) on maize in Viet Nam.

The neotropical fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) is an important lepidopteran pest with a broad geographical distribution (Goergen et al. 2015, Early et al. 2018, Sharanabasappa et al. 2018). Larvae of S. frugiperda feed on more than 350 plant species, including several economically-important crops such as maize, sugarcane or rice (Montezano et al. 2018). Following its invasion of the African continent and of South Asia in 2016 and 2018 respectively, FAW has caused important crop losses and associated livelihood impacts (Baudron et al., 2019). During 2019, FAW rapidly spread across Southeast Asia and FAW-attributed feeding damage was recorded on maize in Viet Nam. In Viet Nam, maize is the second most important staple food crop after rice, is extensively used for livestock production and poultry feed, and thus plays a central role in sustaining rural livelihoods (Dang et al. 2004). Hence, the recent FAW invasion and the anticipated pest-induced yield losses will carry important repercussions for local maize value chains and are likely to degrade farmers' revenue base. In this study, we conducted a morphological and molecular identification of locally-collected FAW individuals to better characterize the species' invasion history in Viet Nam.