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Background: The vegetable leafminer, Liriomyza sativae (Blanchard) is a serious pest of vegetable and ornamental crops in the whole Vietnam. Previous studies indicate that biology of Liriomyza leafminers depends on host plant. The objective of this study was to understand the performance of L. sativae on kidney bean (Phaseolus vulgaris L.) and pak choi (Brassica rapa var. chinensis). Methods: The experiment was carried out at the Laboratory of Entomology, Faculty of Agronomy, University of Agriculture and Forestry, Hue University, Vietnam during 2020 and 2021. The development time of immature stages, longevity and fecundity of L. sativae were investigated on kidney bean and pak choi. Result: The total developmental time from egg to adult emergence of the vegetable leafminer fed on kidney bean was shorter (17.1 days) than that on pak choi (18.2 days). Fecundity of the adults on kidney bean (190.2 eggs) were larger than that on pak choi (73.3 eggs). The results indicated that pak choi was less suitable host plant than kidney bean.

Background: The coconut black-headed caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae) has been a serious defoliator of coconut plants in many coconut producing countries including Vietnam. Trichospilus pupivorus Ferrière (Hymenoptera: Eulophidae) is pupal endo-parasitoid of O. arenosella with high percent parasitism and abundance in the coconut fields and appears to be a good biological control agent against the coconut black-headed caterpillar in Vietnam. The objective of this study was to investigate the developmental biology of T. pupivorus on O. arenosella. Methods: The experiment was carried out at the Faculty of Agronomy, Nong Lam University, Viet Nam during 2020 and 2021. The developmental biology of T. pupivorus on O. arenosella was studied in the laboratory at a constant temperature of 28°C and a photoperiod of 12L: 8D. Result: Total developmental time from egg to adult emergence was 14.0 days. The females laid a mean of 124.2 eggs during an average lifespan of 9.4 days. The number of progenies emergence from a single pupa of O. arenosella was 103.8. The offspring sex ratio was female-biased (8.0%). The results would contribute to the knowledge of the biology of this parasitoid to optimize a mass rearing system for a biological control program against O. arenosella.

It has been reported that the superconductivity of Bi2Sr2Ca2Cu3O10+δ (Bi-2223) can be further enhanced by cation doping with alkaline material such as Na-doping at Ca sites. We investigated the mechanism of the enhancement of superconductivity in Bi1.6Pb0.4Sr2Ca2-xNaxCu3O10+δ (x = 0.00 to 0.06) in terms of valence state and local atomic displacement by way of Cu K-edge X-ray absorption fine structure (XAFS) spectroscopy. The usage of the extended XAFS regularization method enabled us to obtain the pair distribution function and the effective interatomic potential of the in-plane Cu–O pairs. The analysis of XAFS spectra revealed that distortion in the CuO2 plane is relieved as Na contents increase, thereby providing a more stable structure. Furthermore, upon Na-doping, the in-plane Cu–O bond becomes contracted, accompanied by an increase of the average valence states. As a consequence, the increase in the Cu valence by Na-doping seems to induce an adjustment of the CuO2 plane in a direction to drive the superconductivity to enhance.

In this work, we investigated a correlation between superconductivity and interlayer coupling of two different alkaline (Na and K)-substituted Bi1·6Pb0·4Sr2Ca2Cu3O10+δ (BSCCO) polycrystalline samples. The excess conductivity analysis by the Aslamazov-Larkin (AL) and Lawrence-Doniach (LD) theories showed that Na substitution at the Ca site induced a gradual broadening of 3D fluctuation region with increasing interlayer coupling strength, which explains a systematic increase of Tc and a decrease of normal state resistivity. On the other hand, exactly the opposite results were observed in the K-substituted samples in place of Sr. Extended x-ray absorption fine structure (EXAFS) studies revealed that substitution of Na and K generated completely different effects on the local structure around Cu atoms. It is noticeable that the Cu–O bond distance was found to decrease monotonically with the varying amounts of Na, which indicates that the CuO2 layer is stabilized. On the while, the opposite was observed to occur with the varying amounts of K. Unlike the Cu–Ca bond which was the least affected by the substitution, the Cu–Sr bond distance increased drastically with K substitution. All these findings indicate that Na substitution at the Ca site enhances superconductivity with no loss of interlayer interaction, while K substitution at the Sr site weakens superconductivity due to the diminished interlayer interaction.

In terrestrial ecosystems, changes in soil nutrient availability, plant growth or natural enemies can generate important shifts in abundance of organisms at various trophic levels. In agroecosystems the performance of (invasive) herbivores and their impacts on crops is of particular concern. Scientists are presently challenged with making reliable inferences on invader success, natural enemy performance and efficacy of biological control, particularly in tropical agroecosystems. In this study, we assess how trophic regulatory forces (bottom-up vs. top down) influence the success of three globally important pests of cassava. We examine the mealybug species (Hemiptera: Pseudococcidae) of differing host breadth and invasion history: Phenacoccus manihoti, Paracoccus marginatus, and Pseudococcus jackbeardsleyi. Potted plant fertilizer trials were combined with a regional survey in Vietnam, Laos and Cambodia of 65 cassava fields of similar size and age, but with varying soil fertility. Relative abundance of each mealybug invader was mapped along a soil fertility gradient, and contrasted with site-specific measures of parasitism. Potted plant trials revealed strong bottom-up effects for P. manihoti, such that impacts of nitrogen and potassium additions were propagated through to higher trophic levels and substantially boost development and fitness of its specialist parasitoid, Anagyrus lopezi (Hymenoptera: Encyrtidae). Field surveys indicate that mealybug performance is highly species-specific and context-dependent. For example, field-level abundance of P. jackbeardsleyi and P. marginatus, was related to measures of soil fertility parameters, soil texture and plant disease incidence. Furthermore, for P. manihoti, in-field abundance is equally associated with soil texture (i.e., silt content). Principal component analysis (PCA) and regression suggested that P. manihoti and P. marginatus are disproportionately favored in low-fertility conditions, while P. jackbeardsleyi prospers in settings with high organic carbon and phosphorus. Parasitism of P. manihoti by A. lopezi varied greatly with field and soil fertility conditions, and was highest in soils with intermediate fertility levels and where management practices include the addition of fertilizer supplements. Our characterization of the relative performance of invasive mealybugs and strength of parasitism across variable soil fertility conditions will help guide parasitoid release programs and soil management practices that enhance mealybug biological control.

The effect of substrate surface decoration on the critical current density (J c ) of GdBa 2 Cu 3 O 7 − δ (GdBCO) thin films has been investigated. Prior to GdBCO deposition, uniformly-distributed Gd 2 O 3 nanoparticles were applied to a substrate surface by using the pulsed laser deposition technique. GdBCO films deposited on Gd 2 O 3 -decorated SrTiO 3 (STO) substrates showed an enhanced in-field J c in comparison with that of GdBCO film on untreated STO. The J c enhancement may be attributed to both the Gd 2 O 3 nanoparticles located at the film/substrate interface and to induced linear defects that were nearly parallel to the c -axis of the film, as confirmed by the transmission electron microscope analysis. A significantly improved pinning force F p in terms of a larger F pmax values was obtained with Gd 2 O 3 decoration.

The coordination of the functional activities of intestinal CYP3A4 and P-gp in limiting the absorption of xenobiotics in Caco-2 cells was investigated. Growing Caco-2 cells were exposed to increasing concentrations of doxorubicin (1–2 μM) in plastic flasks to encourage a subpopulation of cells, that displayed an intrinsically higher multidrug resistance (mdr) phenotype than the parent cells, to survive and grow. Doxorubicin-exposed (hereinafter referred to as type I cells) and nonexposed Caco-2 cells (parent cells) on collagen-coated inserts were also treated with either 0 (control) or 0.25 μM 1α,25-dihydroxyvitamin D3 to promote cellular CYP3A4 expression. Increased P-gp protein expression, as detected by Western blotting, was noted in type I cells (213 ± 54.35%) compared to that of parent cells (100 ± 6.05%). Furthermore, they retained significantly less [3H]vincristine sulphate (p

A coupled ice, ocean model for forecasting ice conditions on the Newfoundland shelf region is assessed by comparing hindcasts with satellite‐tracked ice beacon displacements and with changes in offshore ice edge location, ice thickness and southern ice extent derived from ice charts. The beacon velocity fields contain short timescale fluctuations which are not resolved by the model. The ratio of rms displacement error divided by the rms beacon displacement is 0.48 after 1 day and 0.23 after 8 days. The decrease in the scaled displacement error with increasing time is related to the short timescale motions. The skill in modelling displacement of the offshore ice edge is lower than in modelling ice displacement. Between mid‐February and mid‐April 1997, the effect of ice melt on the ice edge was a mean onshore displacement of 35 km overcoming an offshore advection of 24 km in 5 days.

Ultrasound transmission and reflection are utilized to characterize the particle retention in depth of fluid-saturated porous samples under a flow of silt solution. The effect of the concentration of particles in the fluid is investigated via measurements of “comparison coefficients” which are the ratio of the Fourier transforms of the reflected (transmitted) signals before and after the particle flow. Numerical computations of the latter coefficients using Biot–Stoll’s theory are compared to the experimental data. The frequential evolution of physical parameters such as bulk and shear moduli are sought. To this end, a gradient descent algorithm is utilized to minimize the differences between the experimental and calculated comparison coefficients. Several concentrations of suspended particles are investigated to check the validity of this inversion method and a good agreement between theory and experiments is observed.

Introduction: Although prenatal diagnosis is widely offered in Vietnam to avoid the birth of a child with a serious genetic disease, preimplantaion genetic diagnosis (PGD) is currently not allowed. To obtain PGD approval, Ministry of Health requires demonstration of competence and safety through well designed research studies. To this end, we designed a prospective study to evaluate survival rate of frozen biopsied embryos and determine post thaw aneuploidy rates. Materials and Methods: A total of 227 day-2-embryos cryopreserved between 2002 and 2007 using either slow freezing or vitrification were consented to research by 37 couples. Following thawing, the embryos were cultured for 24 hours. Only embryos which had further divided and possessed more than 6 blastomeres with less than 20% of fragmentation were selected for the study. One blastomere from each embryo was biopsied using laser assisted hatching system to open its zona pellucida and then the blastomere was fixed in Carnoy’s solution. Chromosomal aneuploidy was assessed by fluorescence in situ hybridization (FISH) analysis using MultiVysion CEP probes (Abbott) for chromomosomes X, Y, 13, 18 and 21. Biopsied embryos were further cultured to the blastocyst stage (72h later). Results: From a total of 227 frozen-thawed embryos, 64.76% (147/227) survived after thawing and 45.81% (104/227) embryos met the selection criteria for further analysis. Of these, 97.1% (101/104) survived after the biopsy procedure and 61.39% (62/101) developed further to blastocyst/hatched embryos. All 101 blastomeres generated clear FISH signals for all 5 chromosomes with 35.6% (36/101) of the embryos demonstrating euploidy. Among 62 blastocyst/hatched embryos that developed, 41.94% (26/62) were euploid and 58.06% (36/62) were aneuploid at the cleavage stage. Conclusion: This study of cryopreserved embryos donated to research conducted at the Infertility Department, TuDu Hospital demonstrates successful biopsy and FISH procedures in a clinical IVF setting. These outcomes compare favorably to that published for well established PGD laboratories by the ESHRE PGD Consortium1 findings demonstrate high competence and safety standards for PGS that should convince the Health Ministry to formulate regulations for clinical PGD and finally approve this reproductive option for at risk couples in Vietnam.