Using three-dimensional modelling of the anterior sclera to investigate the scleral profile in myopic eyes.

PURPOSE: This study used three-dimensional (3D) modelling to investigate scleral profiles in myopic eyes and compare them with emmetropic eyes. METHODS: In this prospective observational study, the eyes of 151 participants were analysed using the corneoscleral profile module (CSP) of the Pentacam HR. Non-rotationally symmetrical ellipsoids were fitted to the anterior scleral sagittal height. Three radii were analysed, namely the nasal-temporal (Rx), superior-inferior (Ry) and anterior-posterior (Rz) orientations. Additionally, the area index (AI) and aspherical parameters (Qxy, Qxz and Qyz) of the anterior sclera-fitted ellipsoid (ASFE) were quantified. RESULTS: The findings showed an increase in Rx (-0.349 mm/D), Ry (-0.373 mm/D), Rz (-1.232 mm/D) and AI (-36.165 mm2 /D) with increasing myopia. From emmetropia to high myopia, the vertical and horizontal planes of the anterior sclera became increasingly prolate (emmetropia, Qxz: 0.02, Qyz: 0.01; low myopia, Qxz: -0.28, Qyz: -0.28; high myopia, Qxz: -0.41, Qyz: -0.43). There were no significant differences in the coronal plane across the three groups (H = 2.65, p = 0.27). The anterior scleral shape of high myopes in the horizontal and vertical planes was more prolate than that of emmetropes and low myopes (Qxz, high myopes vs. low myopes: p = 0.03, high myopes vs. emmetropes: p < 0.001; Qyz, high myopes vs. low myopes: p = 0.04, high myopes vs. emmetropes: p < 0.001). CONCLUSIONS: As the degree of myopia increased, non-uniform anterior scleral enlargement was observed. These findings provide a better understanding of the anterior segment with varying degrees of myopia.

3-D reconstruction of rice leaf tissue for proper estimation of surface area of mesophyll cells and chloroplasts facing intercellular airspaces from 2-D section images.

BACKGROUND AND AIMS: The surface area of mesophyll cells (Smes) and chloroplasts (Sc) facing the intercellular airspace (IAS) are important parameters for estimating photosynthetic activity from leaf anatomy. Although Smes and Sc are estimated based on the shape assumption of mesophyll cells (MCs), it is questionable if the assumption is correct for rice MCs with concave-convex surfaces. Therefore, in this study, we establish a reconstruction method for the 3-D representation of the IAS in rice leaf tissue to calculate the actual Smes and Sc with 3-D images and to determine the correct shape assumption for the estimation of Smes and Sc based on 2-D section images. METHODS: We used serial section light microscopy to reconstruct 3-D representations of the IAS, MCs and chloroplasts in rice leaf tissue. Actual Smes and Sc values obtained from the 3-D representation were compared with those estimated from the 2-D images to find the correct shape-specific assumption (oblate or prolate spheroid) in different orientations (longitudinal and transverse sections) using the same leaf sample. KEY RESULTS: The 3-D representation method revealed that volumes of the IAS and MCs accounted for 30 and 70 % of rice leaf tissue excluding epidermis, respectively, and the volume of chloroplasts accounted for 44 % of MCs. The shape-specific assumption on the sectioning orientation affected the estimation of Smes and Sc using 2-D section images with discrepancies of 10-38 %. CONCLUSIONS: The 3-D representation of rice leaf tissue was successfully reconstructed using serial section light microscopy and suggested that estimation of Smes and Sc of the rice leaf is more accurate using longitudinal sections with MCs assumed as oblate spheroids than using transverse sections with MCs as prolate spheroids.

Non-equilibrium shapes and dynamics of active vesicles.

Active vesicles, constructed through the confinement of self-propelled particles (SPPs) inside a lipid membrane shell, exhibit a large variety of non-equilibrium shapes, ranging from the formation of local tethers and dendritic conformations, to prolate and bola-like structures. To better understand the behavior of active vesicles, we perform simulations of membranes modelled as dynamically triangulated surfaces enclosing active Brownian particles. A systematic analysis of membrane deformations and SPP clustering, as a function of SPP activity and volume fraction inside the vesicle is carried out. Distributions of membrane local curvature, and the clustering and mobility of SPPs obtained from simulations of active vesicles are analysed. There exists a feedback mechanism between the enhancement of membrane curvature, the formation of clusters of active particles, and local or global changes in vesicle shape. The emergence of active tension due to the activity of SPPs can well be captured by the Young-Laplace equation. Furthermore, a simple numerical method for tether detection is presented and used to determine correlations between the number of tethers, their length, and local curvature. We also provide several geometrical arguments to explain different tether characteristics for various conditions. These results contribute to the future development of steerable active vesicles or soft micro-robots whose behaviour can be controlled and used for potential applications.

Interactions of organophosphorus pesticides with ATP-binding cassette (ABC) drug transporters.

Although pharmaceutical companies have to study drug-transporter interaction, environmental contaminant interactions with these transporters are not well characterised. In this study, we demonstrated using in vitro transfected cell line that some organophosphorus pesticides are able to interact with drug efflux transporters like P-glycoprotein, BCRP and MRPs.According to our results, dibrom was found to inhibit only Hoechst binding site of P-gp with an IC50 closed to 77 µM, phosmet inhibited BCRP efflux with an IC50 of 42 µM and only profenofos was able to inhibit BCRP, MRPs and P-gp at two binding sites. As profenofos appeared to be a potent ABC transporter inhibitor, we studied its potential substrate property towards P-gp.Using a docking approach, we developed an in silico tool to study pesticide properties to be a probe or inhibitor of P-gp transporter. From both in silico and in vitro results, profenofos was not considered as a P-gp substrate.Combining both in vitro and docking methods appears to be an attractive approach to select pesticides that would not pass into the blood systemic circulation.

Analytical analysis of anisotropic thermophoresis of a charged spheroidal colloid in aqueous media for extremely thin EDL cases.

Thermophoresis of charged spheroids has been widely applied in biology and medical science. In this work, we report an analysis of the anisotropic thermophoresis of diluted spheroidal colloids in aqueous media for extremely thin EDL cases. Under the boundary layer approximation, we formulate the thermophoretic velocity, the thermophoretic force, and the thermodiffusion coefficient of a randomly dispersed spheroid. The parametric studies show that under the aforementioned conditions, the thermophoresis is anisotropic and its thermodiffusion coefficient should be considered as a vector, DT . The thermodiffusion coefficient values and directions of DT are strongly related to the aspect ratio and the angle θ between the externally applied temperature gradient and the particle's axis of revolution: The increasing aspect ratio enlarges the thermodiffusion coefficient value DT of prolate (oblate) spheroids to a constant value when θ < 60° (θ > 45°), and it reduces DT of prolate (oblate) spheroids to a constant value when θ > 60° (θ < 45°). The thermodiffusion coefficient direction of both prolate and oblate spheroids deviates slightly from -∇T∞ for a small aspect ratio, and such deviation becomes serious for a large aspect ratio.

A bacteriophage infecting Mesorhizobium species has a prolate capsid and shows similarities to a family of Caulobacter crescentus phages.

Mesorhizobium phage vB_MloS_Cp1R7A-A1 was isolated from soil planted with chickpea in Saskatchewan. It is dissimilar in sequence and morphology to previously described rhizobiophages. It is a B3 morphotype virus with a distinct prolate capsid and belongs to the tailed phage family Siphoviridae. Its genome has a GC content of 60.3% and 238 predicted genes. Putative functions were predicted for 57 genes, which include 27 tRNA genes with anticodons corresponding to 18 amino acids. This represents the highest number of tRNA genes reported yet in a rhizobiophage. The gene arrangement shows a partially modular organization. Most of the structural genes are found in one module, whereas tRNA genes are in another. Genes for replication, recombination, and nucleotide metabolism form the third module. The arrangement of the replication module resembles the replication module of Enterobacteria phage T5, raising the possibility that it uses a recombination-based replication mechanism, but there is also a suggestion that a T7-like replication mechanism could be used. Phage termini appear to be long direct repeats of just over 12 kb in length. Phylogenetic analysis revealed that Cp1R7A-A1 is more closely related to PhiCbK-like Caulobacter phages and other B3 morphotype phages than to other rhizobiophages sequenced thus far.

Persistent prolate polymersomes for enhanced co-delivery of hydrophilic and hydrophobic drugs.

Self-assembled polymersomes encapsulate, protect, and deliver hydrophobic and hydrophilic drugs. Though spherical polymersomes are effective, early studies suggest that non-spherical structures may enhance specificity of delivery and uptake due to similarity to endogenous uptake targets. Here we describe a method to obtain persistent non-spherical shapes, prolates, via osmotic pressure and the effect of prolates on uptake behavior. Polyethylene glycol-b-poly(lactic acid) polymersomes change in diameter from 145 ± 6 nm to 191 ± 1 nm and increase in polydispersity from 0.05 ± 0.02 to 0.12 ± 0.01 nm after addition of 50 mM salt. Transmission and scanning electron microscopy confirm changes from spheres to prolates. Prolate-like polymersomes maintain their shape in 50 mM NaCl for seven days. Nile Red and bovine serum albumin-Fluorescein dyes are taken up in greater amounts by SH-SY5Y neural cells when encapsulated in polymersomes. Prolate polymersomes may be taken up more efficiently in neural cells than spherical polymersomes.

The toxicity assessment of phosmet on development, reproduction, and gene expression in Daphnia magna.

The use of pesticides to control pests, weeds, and diseases or to regulate plant growth is indispensable in agricultural production. However, the excessive use of these chemicals has led to significant concern about their potential negative impacts on health and the environment. Phosmet is one such pesticide that is commonly used on plants and animals against cold moth, aphids, mites, suckers, and fruit flies. Here, we investigated the effects of phosmet on a model organism, Daphnia magna using acute and chronic toxicity endpoints such as lethality, mobility, genotoxicity, reproduction, and gene expression. We performed survival experiments in six-well plates at seven different concentrations (0.01, 0.1, 1, 10, 25, 50, 100 µM) as well as the control in three replicates. We observed statistically significant mortality rates at 25 µM and above upon 24 h of exposure, and at 1 µM and above following 48 h of exposure. Genotoxicity analysis, reproduction assay and qPCR analysis were carried out at concentrations of 0.01 and 0.1 µM phosmet as these concentrations did not show any lethality. Comet assay showed that exposure to phosmet resulted in significant DNA damage in the cells. Interestingly, 0.1 µM phosmet produced more offspring per adult compared to the control group indicating a hormetic response. Gene expression profiles demonstrated several genes involved in different physiological pathways, including oxidative stress, detoxification, immune system, hypoxia and iron homeostasis. Taken together, our results indicate that phosmet has negative effects on Daphnia magna in a dose- and time-dependent manner and could also induce lethal and physiological toxicities to other aquatic organisms.

Exploring microscopic pollen morphology in herbaceous Flora: Insights and analysis using scanning electron microscopy.

Microscopic techniques can be applied to solve taxonomic problems in the field of plant systematic and are extremely versatile in nature. This study was focused on the new approaches to visualizing the imaging, tool to cover the micro-structural techniques applied to the pollen study of flowers. The current research was proposed to evaluate microscopic pollen morphological attributes using light and scanning electron microscopy of herbaceous flora from Samarkand, Uzbekistan. A total of 13 herbaceous species, classified into 11 different families were collected, pressed, and identified, and then acetolyzed their pollen to visualize under light and scanning electron microscopy. Herbaceous flora can be characterized by small to very large-sized pollen morphotypes presenting four types of pollen shapes, prolate spheroidal (six species), spheroidal (three species) and prolate and oblate (two species each). The polar diameter and equatorial distance were calculated maximum in Hibiscus syriacus 110.55 and 111.2 µm respectively. Pollen of six different types was found namely tricolporate pollen observed in seven species, tricolpate and pantoporate in two species each, sulcate in Gagea olgae and hexacolpate pollen was examined in Salvia rosmarinus. Exine ornamentation of pollen was examined tectate perforate, verrucate-reticulate, micro-reticulate, reticulate, reticulate-cristatum, gemmate-echinate, echinate-perforate, perforate-striate, rugulate, rugulate-striate, bi-reticulate, reticulate-perforate and perforate-micro-reticulate showing great variations. Exine thickness was noted highest for Rosa canina 2.9 µm and minimum in Punica granatum 0.65 µm. This study of pollen imaging visualization of herbaceous flora contributes to the opportunity for the taxonomic evaluation of and fills knowledge gaps in studies of herbaceous flora identification using classical microscopic taxonomic tools for their accurate identification. RESEARCH HIGHLIGHTS: Pollen in unexplored herbaceous flora of the Samarkand region was studied with light and scanning electron microscopic pollen study. There is a high variation in observed pollen micromorphological characters. Pollen microscopic morphology has important taxonomic value for the identification of herbaceous species.

Facile synthesis of gold nanostars for the duplex detection of pesticide residues in grapes using SERS.

In recent years, concerns have been raised regarding the contamination of grapes with pesticide residues. As consumer demand for safer food products grows, regular monitoring of pesticide residues in food has become essential. This study sought to develop a rapid and sensitive technique for detecting two specific pesticides (phosmet and paraquat) present on the grape surface using the surface-enhanced Raman spectroscopy (SERS) method. Gold nanostars (AuNS) particles were synthesized, featuring spiky tips that act as hot spots for localized surface plasmon resonance, thereby enhancing Raman signals. Additionally, the roughened surface of AuNS increases the surface area, resulting in improved interactions between the substrate and analyte molecules. Prominent Raman peaks of mixed contaminants were acquired and used to characterize and quantify the pesticides. It was observed that the SERS intensity of the Raman peaks changed in proportion to the concentration ratio of phosmet and paraquat. Moreover, AuNS exhibited superior SERS enhancement compared to gold nanoparticles. The results demonstrate that the lowest detectable concentration for both pesticides on grape surfaces is 0.5 mg/kg. These findings suggest that SERS coupled with AuNS constitutes a practical and promising approach for detecting and quantifying trace contaminants in food. PRACTICAL APPLICATION: This research established a novel surface-enhanced Raman spectroscopy (SERS) method coupled with a simplified extraction protocol and gold nanostar substrates to detect trace levels of pesticides in fresh produce. The detection limits meet the maximum residue limits set by the EPA. This substrate has great potential for rapid measurements of chemical contaminants in foods.

Breaking the take home pesticide exposure pathway for agricultural families: workplace predictors of residential contamination.

BACKGROUND: Pesticides used in agriculture can be taken into worker homes and pose a potential risk for children and other family members. This study focused on identification of potential intervention points at the workplace. METHODS: Workers (N = 46) recruited from two tree fruit orchards in Washington State were administered a 63-item pesticide safety questionnaire. Dust was collected from commuter vehicles and worker homes and analyzed for four organophosphorus (OP) pesticides (azinphosmethyl, phosmet, chlorpyrifos, malathion). RESULTS: Geometric mean azinphosmethyl concentrations in dust for three worker groups (16 pesticide handlers, 15 green fruit thinners, 15 organic orchard workers) ranged from 0.027-1.5 µg/g, with levels in vehicle dust higher than in house dust, and levels in house dust from handlers' homes higher than levels from tree fruit thinners' homes. Vehicle and house dust concentrations of azinphosmethyl were highly associated (R(2) = 0.44, P < 0.001). Significant differences were found across worker groups for availability of laundry facilities, work boot storage, frequency of hand washing, commuter vehicle use, parking location, and safety training. CONCLUSIONS: These findings support a focus on intervention activities to reduce take home pesticide exposure closer to the source of contamination; specifically, the workplace and vehicles used to travel to the workplace.

New insight into environmental oxidation of phosmet insecticide initiated by HO˙ radicals in gas and water - a theoretical study.

Phosmet is an organophosphorus insecticide widely used in agriculture to control a range of insects; recently, it was banned by the European Union in 2022 due to its harmful effects. However, its environmental degradation and fate have not yet been evident. Thus, phosmet oxidation by HO˙ radicals was theoretically studied in this work using the DFT approach at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level of theory. Three different mechanisms were considered, including formal hydrogen transfer (FHT), radical adduct formation (RAF), and single electron transfer (SET). The mechanisms, kinetics, and lifetime were studied in the gas and aqueous phases, in addition to its ecotoxicity evaluation. The results show that FHT reactions were dominant in the gas phase, while RAF was more favourable in the aqueous phase at 298 K, while SET was negligible. The branching ratio indicated that H-abstractions at the methyl and the methylene groups were the most predominant, while the most favourable HO˙-addition was observed at the phosphorus atom of the dithiophosphate group. The overall rate constant values varied from 1.2 × 109 (at 283 K) to 1.40 × 109 M-1 s-1 (at 323 K) in the aqueous phase and from 6.29 × 1010 (at 253 K) to 1.32 × 1010 M-1 s-1 (at 323 K) in the gas phase. The atmospheric lifetime of phosmet is about 6 hours at 287 K, while it can persist from a few seconds to several years depending on the temperature and [HO˙] concentration in the aqueous environment. The QSAR-based ecotoxicity evaluation indicates that phosmet and its degradation products are all dangerous to aquatic organisms, although the products are less toxic than phosmet. However, they are generally developmental toxicants and mutagenicity-negative compounds.

A novel strategy for identification of pesticides in different categories by concentration-independent model based on a nanozyme with multienzyme-like activities.

Conventional rapid detection methods are difficult to identify or distinguish various pesticide residues at the same time. And sensor arrays are also limited by the complexity of preparing multiple receptors and high cost. To address this challenge, a single material with multiple properties is considered. Herein, we first found that different categories of pesticides have diverse regulatory behaviors on the multiple catalytic activities of Asp-Cu nanozyme. Thus, a three-channel sensor array based on the laccase-like, peroxidase-like, and superoxide dismutase-like activities of Asp-Cu nanozyme was constructed and successfully used for the discrimination of eight kinds of pesticides (glyphosate, phosmet, isocarbophos, carbaryl, pentachloronitrobenzene, metsulfuron-methyl, etoxazole, and 2-methyl-4-chlorophenoxyacetic acid). In addition, a concentration-independent model for qualitative identification of pesticides has been established, and 100% correctness was achieved in the recognition of unknown samples. Then, the sensor array also exhibited excellent interference immunity and was reliable for real sample analysis. It provided a reference for pesticide efficient detection and food quality supervision.

Lethal and sublethal effects of toxic bait formulations on Doryctobracon areolatus (Hymenoptera: Braconidae) and implications for integrated fruit fly management.

The use of toxic baits has become one of the main methods of management of fruit flies in Brazil. The application of toxic baits may cause side effects on the native parasitoid Doryctobracon areolatus (Hymenoptera: Braconidae). Based on the results, formulations made from the food attractants 3% Biofruit, 1.5% Ceratrap, 1.25% Flyral, 3% Isca Samaritá, 3% Isca Samaritá Tradicional, and 7% sugarcane molasses associated with the Malathion 1000 EC and the ready-to-use toxic bait Gelsura (containing the active ingredient alpha-cypermethrin) were classified as harmful (class 4) to D. areolatus (mortality > 85% at 96 HAE). In contrast, for toxic baits formulated with insecticide phosmet, the mortality ranged from 38% to 72%, classified as slightly harmful or moderately harmful. However, when phosmet was added to the 3% Samaritá Tradicional bait, the mortality was only 3.9% (class 1-harmless), similar to the toxicity observed for the Success 0.02 CB ready-to-use bait (0.24 g a.i. spinosad/l) (<5% mortality). Although toxic baits were formulated with spinosyn-based insecticides, all toxic bait formulations were classified as harmless or slightly harmful (<50% mortality) to D. areolatus, with the exception of 1.5% Ceratrap + spinetoram and 7% Sugarcane molasses + spinosad (≈ 60% mortality-moderately harmful). In addition, these formulations did not show sublethal effects in reducing the parasitism and emergence rate of the F1 generation of D. areolatus in A. fraterculus larvae. The results serve as a basis for the correct use of toxic food baits without affecting the biological control.

Understanding the impact of a non-ionic surfactant alkylphenol ethoxylate on surface-enhanced Raman spectroscopic analysis of pesticides on apple surfaces.

Pesticide active ingredients (AIs) are often applied with adjuvants to facilitate the stability and functionality of AIs in agricultural practice. The objective of this study is to investigate the role of a common non-ionic surfactant, alkylphenol ethoxylate (APEO), on the surface-enhanced Raman spectroscopic (SERS) analysis of pesticides as well as its impact on pesticide persistence on apple surfaces, as a model fresh produce surface. The wetted areas of two AIs (thiabendazole and phosmet) mixed with APEO were determined respectively to correct the unit concentration applied on apple surfaces for a fair comparison. SERS with gold nanoparticle (AuNP) mirror substrates was applied to measure the signal intensity of AIs with and without APEO on apple surfaces after a short-term (45 min) and a long-term (5 days) exposure. The limit of detection (LOD) of thiabendazole and phosmet using this SERS-based method were 0.861 ppm and 2.883 ppm, respectively. The result showed that APEO decreased the SERS signal for non-systemic phosmet, while increased SERS intensity of systemic thiabendazole on apple surfaces after 45 min pesticide exposure. After 5 days, the SERS intensity of thiabendazole with APEO was higher than thiabendazole alone, and there was no significant difference between phosmet with and without APEO. Possible mechanisms were discussed. Furthermore, a 1% sodium bicarbonate (NaHCO3) washing method was applied to test the impact of APEO on the persistence of the residues on apple surfaces after short-term and long-term exposures. The results indicated that APEO significantly enhanced the persistence of thiabendazole on plant surfaces after a 5-day exposure, while there was no significant impact on phosmet. The information obtained facilitates a better understanding of the impact of the non-ionic surfactant on SERS analysis of pesticide behavior on and in plants and helps further develop the SERS method for studying complex pesticide formulations in plant systems.

Palyno-taxonomic approach through light and scanning electron microscopy for the identification of herbaceous Asteraceae species from Sikaram Mountain Pak-Afghan border.

Due to the diverse and rich taxa, Asteraceae needs to explore from the untouched area. In this study, the pollen study was intended to assess the taxonomic value for Asteraceous taxa growing on the Sikaram Mountain Pak-Afghan border. Both microscopic techniques (LM and SEM) play a significant role in the identification and classification of herbaceous species of Asteraceae for their taxonomic and systematic implication. Pollen was observed and measured for the 15 species of Asteraceae. For investigated taxa 15 pollen characters with size, shape, polar view, pollen type, aperture orientation, and exine sculpturing in the eurypalynous pollen. Consequently, the pollen grains are usually Tricolporate, triangular to circular in polar view, while, the shape of pollen varies from subulate, oblate, and prolate along with prolate to spheroidal whereas, sculpturing also varies from Scabrate to micro reticulate, echino-perforate, Scabrate to echinate, echinate to granulate and echinate were observed. Similarly, among the quantitative data minimum values of polar and equatorial were 15.8 ± 0.74 µm in Filago pyramidata and 17.85 ± 0.39 µm in Heteropappus altaicus was measured respectively, while; the length of the spine with the least value of 2.45 ± 0.31 µm in Hertia intermedia and highest with 7.55 ± 0.31 µm was observed in Cirsium wallichii. The Exine thickness is a minimum of 1.70 ± 0.35 µm in Launaea nudicaulis and a maximum of 5.65 ± 3.59 µm in Cirssium vulgare. In addition, the highest pollen fertility (87%) in Centaurea iberica while the highest pollen sterility (32%) was recorded in Cirsium verutum. Furthermore, clustering via UPGMA, PCA, and PCoA analysis was performed for the separation of closely related taxa. It is concluded from this research work that palynological study has a crucial role in taxonomic, pure, and applied sciences. This study can be further authenticated and improved by a Phylogenetic study based on chloroplast DNA analysis & whole genome sequencing. RESEARCH HIGHLIGHTS: Pollen ultrastructure among 15 Asteraceous taxa. Micromorphological attributes measured via LM and SEM. Exine sculpture elements patterns provide accurate identification. Taxonomic keys were developed for its systematics implications.

Contributions of nearby agricultural insecticide applications to indoor residential exposures.

BACKGROUND: Pesticide exposure has been associated with adverse health effects. We evaluated relationships between proximity to agricultural insecticide applications and insecticides in household dust, accounting for land use and wind direction. METHODS: We measured concentrations (ng/g) of nine insecticides in carpet-dust samples collected from 598 California homes. Using a geographic information system (GIS), we integrated the California Pesticide Use Reporting (CPUR) database to estimate agricultural use within residential buffers with radii of 0.5 to 4 km. We calculated the density of use (kg/km2) during 30-, 60-, 180-, and 365-day periods prior to dust collection and evaluated relationships between three density metrics (CPUR unit-based, agricultural land area adjusted, and average daily wind direction adjusted) and dust concentrations. We modeled natural-log transformed concentrations using Tobit regression for carbaryl, chlorpyrifos, cypermethrin, diazinon, and permethrin. Odds of detection were modeled with logistic regression for azinphos-methyl, cyfluthrin, malathion, and phosmet. We adjusted for season, year, occupation, and home/garden uses. RESULTS: Chlorpyrifos use within 1-4 km was associated with 1 to 2-times higher dust concentrations in both the 60- and 365-day periods. Carbaryl applications within 2-4 km of homes 60-days prior to dust collection were associated with 3 to 7-times higher concentrations and the 4 km trend was strongest using the wind-adjusted metric (p-trend = 0.04). For diazinon, there were 2-times higher concentrations for the 60-day metrics in the 2 km buffer and for the CPUR and wind-adjusted metrics within 4 km. Cyfluthrin, phosmet, and azinphos-methyl applications within 4 km in the prior 365-days were associated with 2-, 6-, and 3-fold higher odds of detection, respectively. CONCLUSIONS: Agricultural use of six of the nine insecticides within 4 km is an important determinant of indoor contamination. Our findings demonstrated that GIS-based metrics for quantifying potential exposure to fugitive emissions from agriculture should incorporate tailored distances and time periods and support wind-adjustment for some, but not all insecticides.

Multispectroscopic studies of binding interaction of phosmet with bovine hemoglobin.

Phosmet is a phthalimide derived broad spectrum organophosphate pesticide which is vastly used across the globe to protect several ornamental or horticulture crops. The toxicity of phosmet is of utmost concern because of its direct effect on the nervous system of the victim after exposure. The mechanism of phosmet toxicity was explored by the interaction with the model blood protein which is hemoglobin. Bovine Hemoglobin (BHb) is a major protein of red blood cells (RBCs) that plays an important role in the exchange of gases for respiration and ensures adequate oxygen supply to tissues for oxygenation. In the current study, the interaction of BHb with phosmet was revealed using various spectroscopic techniques. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) studies of BHb in the presence of phosmet showed secondary structural changes in the protein post binding, Fluorescence study shows the involvement of the dynamic quenching predominantly, Van't Hoffs thermodynamic study showed negative enthalpy value and free energy change and negative entropy change that revealed the involvement of hydrogen bonding and van der Waal forces predominantly further revealing spontaneous nature of binding interaction. The shift in Ultraviolet-visible spectra also revealed the nature of the interaction. In-silico study finally deduced the involvement of hydrogen bonding and polar interaction. The study inferred the moderate interaction of BHb with phosmet.

Sensitive fluorescent detection of phosmet and chlortetracycline in animal-derived food samples based on a water-stable Cd(II) chain-based zwitterionic metal-organic framework.

The residues of pesticides and antibiotics have always been a major concern in agriculture and food safety. In order to provide a new method for the rapid detection of organophosphorus pesticides and antibiotics, a novel Cd(II) chain-based zwitterionic metal-organic framework MOF 1 with high sensitivity fluorescence sensing performance was successfully synthesized. A series of researches showed that the water- and pH-stable bifunctional MOF 1 has a great ability to detect phosmet (PSM) and chlortetracycline (CTC) in water through fluorescence quenching effect, with high detection sensitivity, low detection limits (0.0124 µM and 0.0131 µM), short response time (40 s) and reusability. Practical application results revealed that MOF 1 could detect PSM and CTC in milk, beef, chicken and egg samples, with satisfactory recoveries (95.2%-103.7%). As a novel fluorescence probe, MOF 1, is known the first case that can detect PSM in animal-derived samples, and the first dual-function material capable of detecting PSM and CTC. Mechanism studies displayed that competitive absorption and photoinduced electron transfer clearly authenticate the high quenching performance of the material.

Structure and interactions in fluids of prolate colloidal ellipsoids: comparison between experiment, theory, and simulation.

The microscopic structure of fluids of simple spheres is well known. However, the constituents of most real-life fluids are non-spherical, leading to a coupling between the rotational and translational degrees of freedom. The structure of simple dense fluids of spheroids - ellipsoids of revolution - was only recently determined by direct experimental techniques [A. P. Cohen, E. Janai, E. Mogilko, A. B. Schofield, and E. Sloutskin, Phys. Rev. Lett. 107, 238301 (2011)]. Using confocal microscopy, it was demonstrated that the structure of these simple fluids cannot be described by hard particle models based on the widely used Percus-Yevick approximation. In this paper, we describe a new protocol for determining the shape of the experimental spheroids, which allows us to expand our previous microscopy measurements of these fluids. To avoid the approximations in the theoretical approach, we have also used molecular dynamics simulations to reproduce the experimental radial distribution functions g(r) and estimate the contribution of charge effects to the interactions. Accounting for these charge effects within the Percus-Yevick framework leads to similar agreement with the experiment.