Pesticides in Greenhouse Airborne Particulate Matter: Occurrence, Distribution, Transformation Products, and Potential Human Exposure Risks.

Pesticides are frequently sprayed in greenhouses to ensure crop yields, where airborne particulate matter (PM) may serve as a carrier in depositing and transporting pesticides. However, little is known about the occurrence and fate of PM-borne pesticides in greenhouses. Herein, we examined the distribution, dissipation, and transformation of six commonly used pesticides (imidacloprid, acetamiprid, prochloraz, triadimefon, hexaconazole, and tebuconazole) in greenhouse PM (PM1, PM2.5, and PM10) after application as well as the associated human exposure risks via inhalation. During 35 days of experiment, the six pesticides were detected in all PM samples, and exhibited size- and time-dependent distribution characteristics, with the majority of them (>64.6%) accumulated in PM1. About 1.0-16.4% of initially measured pesticides in PM remained after 35 days, and a total of 12 major transformation products were elucidated, with six of them newly identified. The inhalation of PM could be an important route of human exposure to pesticides in the greenhouse, where the estimated average daily human inhalation dose (ADDinh) of the six individual pesticides was 2.1-1.2 × 104 pg/kg day-1 after application (1-35 days). Our findings highlight the occurrence of pesticides/transformation products in greenhouse PM, and their potential inhalation risks should be further concerned.

Ultrathin Two-dimensional Layered Composite Carbosilicates from in situ Unzipped Carbon Nanotubes and Exfoliated Bulk Silica.

A key task in today's inorganic synthetic chemistry is to develop effective reactions, routes, and associated techniques aiming to create new functional materials with specifically desired multilevel structures and properties. Herein, we report an ultrathin two-dimensional layered composite of graphene ribbon and silicate via a simple and scalable one-pot reaction, which leads to the creation of a novel carbon-metal-silicate hybrid family: carbosilicate. The graphene ribbon is in situ formed by unzipping carbon nanotubes, while the ultrathin silicate is in situ obtained from bulk silica or commercial glass; transition metals (Fe or Ni) oxidized by water act as bridging agent, covalently bonding the two structures. The unprecedented structure combines the superior properties of the silicate and the nanocarbon, which triggers some specific novel properties. All processes during synthesis are complementary to each other. The associated synergistic chemistry could stimulate the discovery of a large class of more interesting, functionalized structures and materials.

Effects of industrial green total factor energy efficiency on haze abatement: A spatial econometric analysis based on China's 272 cities.

Environmental issues represented by haze pollution have become the focus of all sectors of society. Industrial activities, especially industrial energy consumption play an important role in it. After the energy consumption of provincial industrial sectors is decomposed into urban industrial sectors through nighttime light data, this study measures the industrial green total factor energy efficiency (IGTFEE) of Chinese cities from 2003 to 2017, and the haze abatement effect of IGTFEE is investigated from the perspective of spatial correlation. The results show that China's haze pollution and IGTFEE present a positive spatial cluster. Additionally, China's haze pollution has obvious path dependence that shows a monotonous decreasing trend as the aggravation of haze pollution. Meanwhile, although haze pollution shows a serious leakage effect, it plays a warning role in haze control in surrounding areas. This effect is stronger in the most severely polluted areas that have higher economic levels. Not only does the improvement of IGTFEE have a positive effect on local haze abatement but can control haze pollution in spatially related areas through spillover effects and spatial feedback effects. However, the effects are significantly heterogeneous and asymmetric across quantiles, where IGTFEE has a marginal diminishing distribution on haze abatement at the middle and low quantiles, but the haze pollution has intensified at the high quantiles due to the energy rebound effect. The results also reveal that haze abatement conforms to the spatial EKC hypothesis in China. Meanwhile, industrial agglomeration, environmental regulations, and industrial upgrading are vital drivers for haze abatement.

Is the sky of smart city bluer? Evidence from satellite monitoring data.

How to win the "Blue Sky Protection Campaign" is becoming the focus all over the world, especially in developing economies, while the implementation of the smart cities initiative (SCI) is seen to be a feasible program to address the negative environmental externalities through Information and Communication Technologies (ICTs), but it lacks the quantitative evidence so far. This study aims to examine the impacts and potential mechanisms of SCI on air pollution governance from the objective satellite monitoring data within a quasi-natural experiment framework. We find that SCI directly reduces the air pollutants concentration such as PM2.5, SO2, NO2, and smog in urban China and improves the air quality very well, which also has significant and positive spillovers on air pollution governance in adjacent cities. This encouraging phenomenon can also be achieved through contributing to green technological innovation, industrial structure upgrading, and decentralizing urban spatial structure, such that most of can be attributed to the technological effect. Heterogeneity analyses demonstrate that the governance effect of air pollution is more obvious in large smart cities, and increases with the expansion of city size. Additionally, the effect performs better in resource-based smart cities and smart cities with stronger financing capacity and air pollution pressure.

[Clinical and genetic analysis of a patient with isolated 17,20 lyase deficiency presenting with pubertal gynecomastia].

OBJECTIVE: To explore the clinical and genetic basis for a patient with isolated 17,20 lyase deficiency presenting with pubertal gynecomastia. METHODS: Clinical manifestation, steroid analysis as well as genetic testing were carried out for a 14-year-old boy featuring puberty gynecomastia. RESULTS: The patient was admitted due to puberty gynecomastia for 2 years. Physical examination showed Tanner B5, G2 and normal blood pressure. Laboratory examination showed normal range of serum potassium and blood gas. Steroid analysis revealed extremely high pregnenolone, progesterone, 17-hydropregnenolone and 17-hydroprogesterone, Correspondingly, the DHEA, androstenedione, testosterone and dihydrotestosterone were low. He was found to harbor compound heterozygous variants of CYP17A1 gene (c.1304T>C/p.F435S and c.1346G>A/p.R449H), among which the R449H variant may result in isolated 17,20 lyase deficiency by altering the structure of redox-partner binding site. CONCLUSION: Isolated 17,20 lyase is a rare cause for puberty gynecomastia. The p.R449H variant of the CYP17A1 gene can result in isolated 17,20 lyase deficiency.

Evaluation of changes in shoulder balance and prediction of final shoulder imbalance during growing-rod treatment for early-onset scoliosis.

BACKGROUND: Obtaining and maintaining final shoulder balance after the entire treatment course is essential for early-onset scoliosis (EOS) patients. The relatively small number of growing-rod (GR) graduates who complete final fusion has resulted in an overall paucity of research on the GR treatment of EOS and a lack of research on the shoulder balance of EOS patients during GR treatment. METHODS: Twenty-four consecutive patients who underwent GR treatment until final fusion were included. Radiographic shoulder balance parameters, including the radiographic shoulder height (RSH), clavicle angle (CA), and T1 tilt angle (T1T), before and after each step of the entire treatment were measured. Shoulder balance changes from GR implantation to the last follow-up after final fusion were depicted and analysed. Demographic data, surgical-related factors, and radiographic parameters were analysed to identify risk factors for final shoulder imbalance. The shoulder balance of patients at different time points was further analysed to explore the potential effect of the series of GR treatment steps on shoulder balance. RESULTS: The RSH showed substantial improvement after GR implantation (P = 0.036), during the follow-up period after final fusion (P = 0.021) and throughout the entire treatment (P = 0.011). The trend of change in the CA was similar to that of the RSH, and the T1T improved immediately after GR implantation (P = 0.037). Further analysis indicated that patients with shoulder imbalance before final fusion showed significantly improved shoulder balance after fusion (P = 0.045), and their RSH values at early postfusion and the final follow-up did not show statistically significant differences from those in the prefusion shoulder balance group (P > 0.05). Early postfusion shoulder imbalance (odds ratio (OR): 19.500; 95% confidence interval (CI) = 1.777-213.949; P = 0.015) was identified as an independent risk factor for final shoulder imbalance. CONCLUSIONS: Shoulder balance could be improved by GR implantation but often changes during the multistep lengthening process, and the final result is relatively unpredictable. Final fusion could further adjust the prefusion shoulder imbalance. Focusing on the prefusion shoulder balance of GR graduates and providing patients with early shoulder balance after fusion might be necessary.

Heterologous expression of heat stress-responsive AtPLC9 confers heat tolerance in transgenic rice.

BACKGROUND: As global warming becomes increasingly severe, it is urgent that we enhance the heat tolerance of crops. We previously reported that Arabidopsis thaliana PHOSPHOINOSITIDE-SPECIFIC PHOSPHOLIPASE C9 (AtPLC9) promotes heat tolerance. RESULTS: In this study, we ectopically expressed AtPLC9 in rice to examine its potential to improve heat tolerance in this important crop. Whereas AtPLC9 did not improve rice tolerance to salt, drought or cold, transgenic rice did exhibit greater heat tolerance than the wild type. High-throughput RNA-seq revealed extensive and dynamic transcriptome reprofiling in transgenic plants after heat stress. Moreover, the expression of some transcription factors and calcium ion-related genes showed specific upregulation in transgenic rice after heat stress, which might contribute to the enhanced heat tolerance. CONCLUSIONS: This study provides preliminary guidance for using AtPLC9 to improve heat tolerance in cereal crops and, more broadly, highlights that heterologous transformation can assist with molecular breeding.

Calmodulin regulates a TRP channel (ADF1) and phospholipase C (PLC) to mediate elevation of cytosolic calcium during acidic stress that induces deflagellation in Chlamydomonas.

Calcium has been implicated in the motility, assembly, disassembly, and deflagellation of the eukaryotic flagellum or cilium (exchangeable terms). Calmodulin (CaM) is known to be critical for flagellar motility; however, it is unknown whether and how CaM is involved in other flagella-related activities. We have studied CaM in Chlamydomonas, a widely used organism for ciliary studies. CaM is present in the cell body and the flagellum, with enrichment in the basal body region. Loss of CaM causes shortening of the nucleus basal body connector and impairs flagellar motility and assembly but not flagellar disassembly. Moreover, the cam mutant is defective in pH shock-induced deflagellation. The mutant deflagellates, however, upon mechanical shearing and treatment with mastoparan or detergent undergo permeabilization in the presence of calcium, indicating the cam mutant is defective in elevations of cytosolic calcium induced by pH shock, rather than by the deflagellation machinery. Indeed, the cam mutant fails to produce inositol 1,4,5-trisphosphate. Biochemical and genetic analysis showed that CaM does not directly activate PLC. Furthermore, CaM interacts with ADF1, a transient receptor channel that functions in acid-induced calcium entry. Thus, CaM is a critical regulator of flagellar activities especially those involved in modulating calcium homeostasis during acidic stress.-Wu, Q., Gao, K., Zheng, S., Zhu, X., Liang, Y., Pan, J. Calmodulin regulates a TRP channel (ADF1) and phospholipase C (PLC) to mediate elevation of cytosolic calcium during acidic stress that induces deflagellation in Chlamydomonas.

An Improved ACKF/KF Initial Alignment Method for Odometer-Aided Strapdown Inertial Navigation System.

For a land-vehicle strapdown inertial navigation system (SINS), the problem of initial alignment with large misalignment angle in-motion needs to be solved urgently. This paper proposes an improved ACKF/KF initial alignment method for SINS aided by odometer. The SINS error equation with large misalignment angle is established first in the form of an Euler angle. The odometer/gyroscope dead reckoning (DR) error equation is deduced, which makes the observation equation linear when the position is taken as the observation of the Kalman filter. Then, based on the cubature Kalman filter, the Sage-Husa adaptive filter and the characteristics of the observation equation, an improved ACKF/KF method is proposed, which can accomplish initial alignment well in the case of unknown measurement noise. Computer simulation results show that the performance of the proposed ACKF/KF algorithm is superior to EKF, CKF and AEKF method in accuracy and stability, and the vehicle test validates its advantages.

An Optimization-Based Initial Alignment and Calibration Algorithm of Land-Vehicle SINS In-Motion.

For a running freely land-vehicle strapdown inertial navigation system (SINS), the problems of self-calibration and attitude alignment need to be solved simultaneously. This paper proposes a complete alignment algorithm for the land vehicle navigation using Inertial Measurement Units (IMUs) and an odometer. A self-calibration algorithm is proposed based on the global observability analysis to calibrate the odometer scale factor and IMU misalignment angle, and the initial alignment and calibration method based on optimal algorithm is established to estimate the attitude and other system parameters. This new algorithm has the capability of self-initialization and calibration without any prior attitude and sensor noise information. Computer simulation results show that the performance of the proposed algorithm is superior to the extended Kalman filter (EKF) method during the oscillating attitude motions, and the vehicle test validates its advantages.

Molecular mechanisms governing plant responses to high temperatures.

The increased prevalence of high temperatures (HTs) around the world is a major global concern, as they dramatically affect agronomic productivity. Upon HT exposure, plants sense the temperature change and initiate cellular and metabolic responses that enable them to adapt to their new environmental conditions. Decoding the mechanisms by which plants cope with HT will facilitate the development of molecular markers to enable the production of plants with improved thermotolerance. In recent decades, genetic, physiological, molecular, and biochemical studies have revealed a number of vital cellular components and processes involved in thermoresponsive growth and the acquisition of thermotolerance in plants. This review summarizes the major mechanisms involved in plant HT responses, with a special focus on recent discoveries related to plant thermosensing, heat stress signaling, and HT-regulated gene expression networks that promote plant adaptation to elevated environmental temperatures.

Efficacy and safety of polymer-free stent versus polymer-permanent drug-eluting stent in patients with acute coronary syndrome: a meta-analysis of randomized control trials.

BACKGROUND: The efficacy and safety of polymer-free stent (PFS) versus permanent polymer drug-eluting stent (PPDES) in patients undergoing percutaneous coronary intervention (PCI) remain controversial. Our meta-analysis was undertaken to evaluate and compare the efficacy and safety of PFS with those of PPDES in patients undergoing PCI. METHODS: We searched PubMed, Cochrane Library, EMBASE, and Clinical Trials.gov databases for randomized controlled trials (RCTs). The primary endpoints were incidence of stent thrombosis (ST) and target-lesion revascularization (TLR). The secondary endpoints included the incidence of major adverse cardiovascular events (MACE), myocardial infarction (MI), cardiac death (CD), late lumen loss (LLL), and diameter stenosis (DS). Subgroup analyses were also conducted based on the follow-up time. RESULTS: Eleven RCTs met the including criteria, and 8616 patients were included in the study. No significant differences were observed between PFS and PPDES treatments in the incidence of ST (RR 0.90; 95% CI: 0.62-1.31; P = 0.58; I 2  = 0), TLR (RR 0.87; 95% CI: 0.76-1.00; P = 0.05; I 2  = 37%), CD (RR 0.89; 95% CI: 0.72-1.10; P = 0.28; I 2  = 0), MI (RR 0.87; 95% CI: 0.71-1.05; P = 0.15; I 2  = 0), LLL (SMD 0.01; 95% CI: -0.29-0.30; P = 0.96; I2 = 90%), and DS (SMD -0.01; 95% CI: - 0.25 to 0.23; P = 0.93; I2 = 83%). Meanwhile, the patients with PFS had a lower incidence of MACE (RR 0.87; 95% CI: 0.78-0.97; P = 0.01; I 2  = 0) than those with PPDES. CONCLUSION: In the overall analysis, patients with PFS presented a lower risk of MACE versus PPDES, but no significant difference were obtained in the risk of ST, TLR, MI, CD, DDD and DS. In the Short term follow up, patients with PSF presented a lower risk of TLR compared with PPDES.

A Facile Green Synthesis of Silver Nanoparticles Based on Poly-L-Lysine.

In this paper, we report a novel synthesis method for silver nanoparticles with facilely controllable morphology under mild conditions. The particles were synthesized by reducing silver nitrate in the presence of water soluble polymer of poly-L-Lysine (PLL) which was used as reducing agent and stabilizer. Experimental results revealed that size variation and overall formation mechanism of the resulting silver particles were mostly determined by the conformation of PLL which was in turn controlled by pH of solution and temperature. Due to biological activity and response ability of PLL to outer stimuli, the method provides a facile and controllable method for producing silver particles with different morphologies. We believe that the synthesis method will contribute to applications of the PLL and silver particles in biomaterials.

Association of longevity with TNF-α G308A and IL-6 G174C polymorphic inflammatory biomarkers in Caucasians: a meta-analysis.

BACKGROUND: Mutations in genes encoding tumor necrosis factor (TNF)-α and interleukin (IL)-6 were previously shown to affect mortality. Single nucleotide polymorphisms (SNPs) in the functional promoter regions of TNF-α (G308A) and IL-6 (G174C) are among the most widely studied. OBJECTIVES: To determine whether TNF-α G308A and IL-6 G174C SNPs confer susceptibility to longevity, we performed a meta-analysis to comprehensively estimate the association between these SNPs and longevity in long-lived individuals (LLI, aged ≥ 80 years). MATERIALS AND METHODS: Studies addressing the role of TNF-α and IL-6 SNPs in longevity were identified from the PubMed database. Pooled ORs with 95 % confidence intervals (CIs) were used to assess the association between SNPs and longevity. RESULTS: The meta-analysis was based on four studies of TNF-α G308A and nine of IL-6 G174C, covering a total of 2945 LLI individuals and 2992 controls. Overall, no significantly increased risks were observed for G308A [A vs. G (additive model): OR = 0.98, 95 % CI = 0.79-1.22, p = 0.852; AA + AG vs. GG (dominant model): OR = 0.97, 95 % CI = 0.75-1.24, p = 0.791] or for G174C [C vs. G (additive model): OR = 1.07, 95 % CI = 0.94-1.22, p = 0.293; CC + CG vs. GG (dominant model): OR = 1.09, 95 % CI = 0.93-1.28, p = 0.299]. There was no change in the significance when a cutoff age of ≥ 90 years was introduced. CONCLUSIONS: We found no evidence that the TNF-α G308A and IL-6 G174C SNPs affected the probability of reaching an advanced age in Caucasians, and that they have little effect on delaying the onset and progression of age-related diseases, but this does not rule out the possibility of population-specific effects caused by different genes and/or environmental factors and their interactions.

Marine n-3 PUFA protects hearts from I/R injury via restoration of mitochondrial function.

OBJECTIVES: Overwhelming evidence shows that dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) elicits protective effects on patients with cardiovascular disease. However, the detailed mechanisms underlying n-3 PUFA-mediated cardioprotection are unknown, and examined in the present study. METHODS: We evaluated heart performances with Langendorff perfusion apparatus. Meanwhile, whole mitochondria were purified from non-perfused hearts for functional assessment, and lipid peroxidation level was measured as well. RESULTS: Compared with control groups, hearts from n-3 PUFA-supplemented rats showed improved functional recovery and reduced tissue injury following ischemia/reperfusion (I/R). Furthermore, the mitochondrial function of PUFA-treated hearts was significantly enhanced, as demonstrated by biochemical analysis of respiratory chain activity. In addition, thiobarbituric acid-reactive substance or TBARS assay revealed that lipid peroxidation product, malondialdehyde or MDA, in the mitochondria was significantly reduced by PUFA treatment. CONCLUSION: Taken together, our data indicate that marine n-3 PUFA could improve cardiac performance after I/R injury by restoring mitochondrial respiratory activities and attenuating lipid peroxidation.

Arabidopsis thaliana phosphoinositide-specific phospholipase C isoform 3 (AtPLC3) and AtPLC9 have an additive effect on thermotolerance.

The heat stress response is an important adaptation, enabling plants to survive challenging environmental conditions. Our previous work demonstrated that Arabidopsis thaliana Phosphoinositide-Specific Phospholipase C Isoform 9 (AtPLC9) plays an important role in thermotolerance. During prolonged heat treatment, mutants of AtPLC3 showed decreased heat resistance. We observed no obvious phenotypic differences between plc3 mutants and wild type (WT) seedlings under normal growth conditions, but after heat shock, the plc3 seedlings displayed a decline in thermotolerance compared with WT, and also showed a 40-50% decrease in survival rate and chlorophyll contents. Expression of AtPLC3 in plc3 mutants rescued the heat-sensitive phenotype; the AtPLC3-overexpressing lines also exhibited much higher heat resistance than WT and vector-only controls. The double mutants of plc3 and plc9 displayed increased sensitivity to heat stress, compared with either single mutant. In transgenic lines containing a AtPLC3:GUS promoter fusion, GUS staining showed that AtPLC3 expresses in all tissues, except anthers and young root tips. Using the Ca(2+)-sensitive fluorescent probe Fluo-3/AM and aequorin reconstitution, we showed that plc3 mutants show a reduction in the heat-induced Ca(2+) increase. The expression of HSP genes (HSP18.2, HSP25.3, HSP70-1 and HSP83) was down-regulated in plc3 mutants and up-regulated in AtPLC3-overexpressing lines after heat shock. These results indicated that AtPLC3 also plays a role in thermotolerance in Arabidopsis, and that AtPLC3 and AtPLC9 function additionally to each other.

Correction: Gao et al. Research on Compressive Strength of Manufactured Sand Concrete Based on Response Surface Methodology. Materials 2024, 17, 195.

In the original publication [...].

Plasma exchange treatment of a diabetic ketoacidosis child with hyperlipidemia to avoid pancreatitis: a case report.

Type 1 diabetes mellitus (T1DM) is a metabolic disorder characterized by an absolute deficiency of insulin due to pancreatic failure. Diabetes ketoacidosis (DKA) has emerged as one of the most common complications of T1DM. Although exceedingly rare, the onset of T1DM with DKA may result in lipemia secondary to severe hypertriglyceridemia (HTG), accounting for several cases in the pediatric population. Along this line, plasma exchange treatment in children with DKA and severe hyperlipidemia has only been reported in some cases. In this case report, the diagnosis of an 11-year-old girl with diabetes ketoacidosis accompanied by severe HTG, along with subsequent plasma exchange treatment, is presented. Initially, the patient received initial management with crystalloid fluid bolus and intravenous insulin therapy. Despite rapid correction of acidosis, persistent HTG subsequently prompted the plasma exchange treatment. A total of three sessions were administered over 2 days, leading to a significant reduction in the triglyceride levels and corneal opacity resolution, indicating a successful therapeutic intervention.

Amino acid-induced synthesis of chiral AgAuPt nanoparticles with branched structure for circularly polarized enantioselective photoelectrocatalytic water splitting.

Chiral Plasmonic nanomaterials have gradually illustrated intriguing circularly polarized light (CPL)-dependent properties in photocatalysis due to their unique chiral optical activity. However, the connection between chiral characteristics and catalytic performance of these materials in cooperative systems is rarely reported and remains a challenge task. In this work, branched AgAuPt nanoparticles induced by L/d-cysteine (Cys) with strong and perfectly symmetric circular dichroism (CD) signals are synthesized. Chiral branched AgAuPt nanoparticles firstly exhibit superior typical electrocatalytic performance. In the photoelectrocatalytic system, chiral branched AgAuPt nanoparticles demonstrate selective catalytic water splitting performance. Specifically, chiral branched AgAuPt with related CPL irradiation exhibits enhanced acidic hydrogen evolution reaction (HER) performance. Under the continuous irradiation of related CPL, the chiral catalyst generates more heat, which further increases the catalytic activity. This contribution of heat is supported by density functional theory (DFT) calculation results. The changes in chiroptical activity during this process are recorded by variable temperature CD spectra. This work provides a novel paradigm for designing chiral catalysis systems and emphasizes the profound promise of chiral plasmonic nanomaterials as chiral catalysts.

Comparative uptake, translocation and metabolism of phenamacril in crops under hydroponic and soil cultivation conditions.

Many studies investigate the plant uptake and metabolism of xenobiotics by hydroponic experiments, however, plants grown in different conditions (hydroponic vs. soil) may result in different behaviors. To explore the potential differences, a comparative study on the uptake, translocation and metabolism of the fungicide phenamacril in crops (wheat/rice) under hydroponic and soil cultivation conditions was conducted. During 7-14 days of exposure, the translocation factors (TFs) of phenamacril were greatly overestimated in hydroponic-wheat (3.6-5.2) than those in soil-wheat systems (1.1-2.0), with up to 3.3 times of difference between the two cultivation systems, implying it should be cautious to extrapolate the results obtained from hydroponic to field conditions. M-144 was formed in soil pore water (19.1-29.9 µg/L) in soil-wheat systems but not in the hydroponic solution in hydroponics; M-232 was only formed in wheat shoots (89.7-103.0 µg/kg) under soil cultivation conditions, however, it was detected in hydroponic solution (20.1-21.2 µg/L), wheat roots (146.8-166.0 µg/kg), and shoots (239.2-348.1 µg/kg) under hydroponic conditions. The root concentration factors (RCFs) and TFs of phenamacril in rice were up to 2.4 and 3.6 times higher than that in wheat for 28 days of the hydroponic exposure, respectively. These results highlighted that cultivation conditions and plant species could influence the fate of pesticides in crops, which should be considered to better assess the potential accumulation and transformation of pesticides in crops.