A Study on the Damage and Economic Threshold of the Soybean Aphid at the Seedling Stage

Both plot inoculation experiments and field pest scouting at the seedling stage indicated that soybean yield losses were closely related to the number of soybean aphids and the proportion of plants colonized by soybean aphids. The main factors affecting the soybean yield were decrease in plant height and number of pods and seeds, owing to injury by soybean aphids at the seedling stage. Under existing production conditions, the economic injury level was 3.36%. The control threshold was 500 soybean aphids per 100 plants, with 35% of plants colonized by soybean aphids.Originating text in Chinese.Citation: Wang, Xibei, Fang, Yihao, Lin, Zhizhong, Zhang, Lirong, Wang, Huadi. (1994). A Study on the Damage and Economic Threshold of the Soybean Aphid at the Seedling Stage. Plant Protection (Institute of Plant Protection, CAAS, China), 20, 12-13

Baicalin Protects Mice Brain From Apoptosis in Traumatic Brain Injury Model Through Activation of Autophagy

Autophagy is associated with secondary injury following traumatic brain injury (TBI) and is expected to be a therapeutic target. Baicalin, a neuroprotective agent, has been proven to exert multi-functional bioactive effects in brain injury diseases. However, it is unknown if Baicalin influences autophagy after TBI. In the present study, we aimed to explore the effects that Baicalin had on TBI in a mice model, focusing on autophagy as a potential mechanism. We found that Baicalin administration significantly improved motor function, reduced cerebral edema, and alleviated disruption of the blood-brain barrier (BBB) after TBI in mice. Besides, TBI-induced apoptosis was reversed by Baicalin evidenced by Nissl staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and the level of cleaved caspase-3. More importantly, Baicalin enhanced autophagy by detecting the autophagy markers (LC3, Beclin 1, and p62) using western blot and LC3 immunofluorescence staining, ameliorating mitochondrial apoptotic pathway evidenced by restoration of the TBI-induced translocation of Bax and cytochrome C. However, simultaneous treatment with 3-MA inhibited Baicalin-induced autophagy and abolished its protective effects on mitochondrial apoptotic pathway. In conclusion, we demonstrated that Baicalin enhanced autophagy, ameliorated mitochondrial apoptosis and protected mice brain in TBI mice model

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Regrown Extrinsic Base InP HBT with Sub-100nm Emitter Contact

This work presents the efforts pursued to optimize InP HBTs for power amplifiers above 100 GHz. Emitter width We reduction to sub-100nm dimension is achieved using a novel cosputtered Ti4wt%W emitter metal, and high power ICP dry etching. The cosputtering process enables fine-tuning of TiW alloy composition for vertical dry etch profile along sidewalls of the 600nm tall emitter metal, retaining sub-100nm emitter width from top to bottom. Base contacts are formed by low-temperature MOCVD regrowth (490 ◦C) of thick p-GaAs (> 4 × 20 cm−3) extrinsic base on the intrinsic p-InGaAs or pGaAsSb base layer, and subsequent UV i-line lift-off of e-beam deposited Pt/Ti/Pd/Au metal stack. Low overall base contact resistivity ρb,c is extracted by TLM on scaled sub100nm We DC “large area” devices to be 0.98 ± 0.4Ω-um2, which meets the requirement for >2THz fmax scaling. The larger bandgap of p-GaAs allows direct abutment of the regrown extrinsic base against sides of the n-InP emitter semiconductor, while blocking undesired electron injection into the extrinsic base. The extended regrown extrinsic base, thus, lowers Rgap by a factor of >2 between the base contact metal and emitter semiconductor, a significant contributor to Rbb in deep submicron HBTs, thanks to themuch lower sheet resistance of the extrinsic base (ρs,ex < 300Ω/sq). Hydrogen passivation of carbon dopants in the p-InGaAs intrinsic base layer is found, and partially reversed with an in-situ N2 anneal in MOCVD before temperature ramp down. Lateral hydrogen out-diffusion is believed to limit carbon dopant reactivation as the smallest We devices showed the lowest apparent intrinsic base sheet resistance (ρs,in = 1900Ω/sq) after the N2 anneal. While the added base spreading resistance Rspread underneath emitter semiconductor is manageable in sub-100nm We devices, DC devices with a GaAsSb intrinsic base are studied as a passivation-proof alternative to InGaAs for maximum Rbb scaling. Collector-base capacitance Ccb scaling is intentionally excluded in this work, so is vertical epitaxial scaling for higher fT , as both face challenges in terms of lithographic and semiconductor doping limits. RF device integration faced tremendous logistic difficulties due to the pandemic lockdown. Nevertheless, working RF devices with fmax in excess of 300GHz are demonstrated. In addition, a detailed review of conventional InP HBT scaling roadmap shows drawbacks of continued Ccb, and fT scaling in sub-100nm We process (e.g., high Rgap, and stagnating Ccb) previously overlooked due to simplified assumptions. It can be shown that conventional beyond-130-nm technology nodes offer comparable or worse device performance, a trend that can be reversed by the insertion of the regrown extrinsic base process module already a reality in SiGe HBT

Export Promotion through Exchange Rate Policy: Exchange Rate Depreciation or Stabilization?

Exchange rate movements affect exports in two ways -- its depreciation and its variability (risk). A depreciation raises exports, but the associated exchange rate risk could offset that positive effect. The present paper investigates the net effect for eight Asian countries using a dynamic conditional correlation bivariate GARCH-M model that simultaneously estimates time varying correlation and exchange rate risk. Depreciation encourages exports, as expected, for most countries, but its contribution to export growth is weak. Exchange rate risk contributes to export growth in Malaysia and the Philippines, leading to positive net effects. Exchange rate risk generates a negative effect for six of the countries, resulting in a negative net effect in Indonesia, Japan, Singapore, Taiwan and a zero net effect in Korea and Thailand. Since the negative effect of exchange rate risk may offset, or even dominate, positive contributions from depreciation, policy makers need to reduce exchange rate fluctuation along with and possibly before efforts to depreciate the currency

Does Exchange Rate Risk Affect Exports Asymmetrically? Asian Evidence

The effects of exchange rate risk have interested researchers, since the collapse of fixed exchange rates. Little consensus exists, however, regarding its effect on exports. Previous studies implicitly assume symmetry. This paper tests the hypothesis of asymmetric effects of exchange rate risk with a dynamic conditional correlation bivariate GARCH(1,1)-M model. The asymmetry means that exchange rate risk (volatility) affects exports differently during appreciations and depreciations of the exchange rate. The data include bilateral exports from eight Asian countries to the US. The empirical results show that real exchange rate risk significantly affects exports for all countries, negative or positive, in periods of depreciation or appreciation. For five of the eight countries, the effects of exchange risk are asymmetric. Thus, policy makers can consider the stability of the exchange rate in addition to its depreciation as a method of stimulating export growth