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Herein, an electroreductive carboxylation of organic carbon-halogen bonds (X=Br and Cl) promoted by catalytic amounts of naphthalene as an organic mediator is reported. This transformation proceeds smoothly under mild conditions with a broad substrate scope of 59 examples, affording the valuable and versatile carboxylic acids in moderate to excellent yields without the need of costly transition metal, wasted stoichiometric metal reductants, or sacrificial anodes. Further late-stage carboxylations of natural product and drug derivatives demonstrate its synthetic utility. Mechanistic studies confirmed the activation of carbon-halogen bonds via single-electron transfer and the key role of naphthalene in this reaction.

Background Rice stripe virus (RSV) is one of the most serious rice diseases in East Asia. The small brown planthopper (SBPH), Laodelphax striatellus, is an economically important rice pest. SBPH transmits RSV horizontally and vertically, resulting in serious rice economic losses. Exposure to sublethal doses of insecticides can induce many physiological and cellular changes in insects. However, the mechanism underlying triazophos-induced RSV vertical transmission remains unclear. Here, we investigated the role of vitellogenin (Vg) in triazophos-induced RSV vertical transmission. Results RSV vertical transmission rates were significantly induced by sublethal exposure to triazophos. The transcript abundance of viral RNA3 segment (RNA3) and capsid protein (CP) in the ovaries of SBPH were also significantly increased. Triazophos induced the expression level of Vg in L. striatellus (LsVg) and increased the contents of ovarian protein and fat body protein. Knockdown of Vg significantly reduced the expression levels of LsVg and Vg receptor (LsVgR), and decreased RSV accumulations in the ovaries. Double-stranded Vg (dsVg)-mediated down-regulation could be rescued by exposure to triazophos. Vertical transmission rate of the dsVg-injected group was significantly decreased compared with the dsGFP-injected group, and triazophos significantly rescued the RSV vertical transmission rate of the dsVg-injected group. Conclusion Our results indicate that triazophos-induced RSV vertical transmission is associated with Vg. This work will help us to further elucidate sublethal doses of insecticides-mediated effects and develop new strategies for pest control. © 2019 Society of Chemical Industry.

Background Thyroid nodules are very common. Ultrasound (US) and fine needle aspiration (FNA) are both integral in cancer screening. This study investigated the concordance between thyroid nodule sizes measured by US and gross pathologic examination and their relationship with malignancy. Methods A retrospective design was used to select consecutive patients with proven carcinoma of the thyroid. The number and maximum diameter of nodules, rates and types of malignancy, as well as predictors of malignancy were determined. Results The 10 944 patients examined had 15 283 thyroid nodules, 44.6% of which were malignant. Of the 4449 nodules sampled by FNA and the 8748 not sampled by FNA, 76.5% and 30.5% were malignant, respectively. The sensitivity, specificity, positive and negative predictive values (NPVs), and overall accuracy of FNA based on final pathology were 97.9%, 96.3%, 98.8%, 93.5%, and 97.5%, respectively. Nodule sizes determined by US were comparable with most nodules having either the same size range (n = 2959, 77.7%) or differing only by one size range (n = 770, 20.5%). Conclusions Thyroid nodule size is inversely related to malignancy risk, as larger nodules have lower malignancy rates. Nodule size estimated by US shows relatively good correlation with final pathologic size. However, thyroid nodules should undergo FNA regardless of size. If the FNA is not benign, nodule size should influence therapeutic decision making.

This study focused on using carbon-14-labeled few-layer graphene (FLG) to determine its uptake, distribution, transformation, and depuration in rice plants. After 7 d hydroponic exposure to FLG suspension at 250 μg L-1 , roots accumulated 694.8 mg kg-1 graphene and shoots had 53.7 mg kg-1 graphene from intra-plant translocation. FLG could likely pass through the cell wall and membrane and enter the chloroplast in the shoots. After 14 days of depuration, only about 15 % of the accumulated FLG were eliminated into the depuration solution with about 70 % of graphene retained in the plants. About 9 % of the accumulated FLG was degraded to 14 CO2 and proposed that reaction with OH. in the leaves may likely contribute to the degradation of FLG, which had structural defects. These findings have an important impact on the long-term environmental fate of graphene-related materials in soil-plant systems.

This paper investigates the optimal control design methodology for linear systems which are collaboratively manipulated by multiple agents based on choices such that certain team targets are achieved. By minimizing the average energy cost subject to the set of specified target-state constraints based on modern variation theory and the Lagrange method, a series of optimal control solutions are established for linear scalar and vector systems jointly controlled by two agents. In addition, a set of sub-optimal controls are derived, which can lead to a tight upper bound on the average energy cost.

A seed mix strategy has been used to provide refuge to susceptible insects for resistance management in planting transgenic maize expressing Bacillus thuringiensis Berliner (Bt) proteins. To determine whether larval movement in a seed mix planting creates favorable conditions for resistant heterozygotes of a target pest, performance of Cry1Ab-susceptible (SS) and -heterozygous resistant (RS) populations of the sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), was evaluated in sequential feeding on non-Bt and Cry1Ab (event MON 810) maize plant tissue. For each insect population, nine feeding sequences were employed. SS and RS feeding on non-Bt plants for their entire larval stages survived well and >60% of the adult pairs produced viable eggs, with an average of 269 progeny per female, whereas none of the two populations on Bt maize plants survived to the pupal stage. SS larvae could not develop to adults if the larvae fed on non-Bt plants for ≤15 days and then moved to Bt plants. In contrast, 4.2–29.2% of RS larvae that fed on non-Bt plants for ≥9 days and then moved to Bt plants developed to adults, and 63.6% of pairs of these adults produced viable eggs, with an average of 185 progeny per female. For SS larvae that fed on Bt plants for 1 or 2 days and then moved to non-Bt plants, few larvae developed to adults with varied emergence times, whereas 28.1 and 13.5% RS larvae feeding on Bt plants for 1 and 2 days, respectively, successfully developed to adults; 43.8% of pairs of these adults produced viable eggs, with an average of 220 progeny per female. For the case of the single Bt gene maize plants (event MON 810), the results suggest that RS insects may have advantages in survival and reproduction over SS if RS larvae hatch and feed on Bt plants during the first 1 or 2 days and then move to non-Bt plants. This advantage is less for RS larvae that hatch and feed on non-Bt plants first and then move to Bt plants, unless the larval movement occurs in the later stages (e.g., fourth or fifth instars).

Recently, a new method called the local polynomial periodogram-Hough transform (LHT) was proposed for linear frequency modulated (LFM) signal detection. In this letter, a closed-form expression of the output signal-to-noise ratio is derived for the LHT, showing that the method exhibits a threshold effect for LFM signal detection. Comparisons with the pseudo-Wigner-Hough transform (PWHT) show that the threshold of the LHT is lower (better) than that of the PWHT.