Hopf physical reservoir computer for reconfigurable sound recognition.

The Hopf oscillator is a nonlinear oscillator that exhibits limit cycle motion. This reservoir computer utilizes the vibratory nature of the oscillator, which makes it an ideal candidate for reconfigurable sound recognition tasks. In this paper, the capabilities of the Hopf reservoir computer performing sound recognition are systematically demonstrated. This work shows that the Hopf reservoir computer can offer superior sound recognition accuracy compared to legacy approaches (e.g., a Mel spectrum + machine learning approach). More importantly, the Hopf reservoir computer operating as a sound recognition system does not require audio preprocessing and has a very simple setup while still offering a high degree of reconfigurability. These features pave the way of applying physical reservoir computing for sound recognition in low power edge devices.

Fate characteristics of the chiral pesticide dufulin in flooded anaerobic soils and its interaction with soil microorganisms.

Dufulin (DFL), a plant antiviral agent synthesized in China, has been widely used to control viral diseases in rice, tobacco, tomato, and other crops. However, its fate in flooded anaerobic soils, which is essential for environmental risk assessment, remains unknown. Using the 14C tracer technique, the fate of 14C-labeled DFL isomers in flooded anaerobic soils was systematically investigated in this study. Over the 100-day incubation, a small part of 14C-DFL enantiomer was mineralized to 14CO2 (< 10.44 %) or entered the surface water phase (< 6.69 %), with most of the 14C (> 80.40 %) remaining in the subsoil. The residues in all tested soils were gradually converted from extractable residues (ERs) to nonextractable residues (NERs). At the end of incubation, the fraction of 14C-NERs reached 5.38-23.77 %. The half-life (t1/2) of the DFL parent in soil is relatively long under submerged anaerobic conditions, especially in Fluvo-aquic soil, up to 277.26-315.07 days, which exceeds the risk threshold recommended by the Stockholm Convention (< 180 days). Soil type and microbial activity influenced the fate of DFL in flooded soils and microbial analysis showed that 2.0 mg kg-1 DFL had no obvious impact on soil bacterial richness and function. Pseudomonas spp. was estimated to be a potentially efficient degrading genus for DFL. No enantioselective behaviors were detected in this study. This research provides a theoretical basis for evaluating the environmental impact and ecological safety of DFL application.

Insights into the Fate of the Novel Pesticide Vanisulfane from Animal Manure in Plant-Soil Systems: Assisted by Carbon-14 Labeling.

Pesticide use can result in plant residues, which can be ingested by livestock consuming plant-derived feed and appear in manure. When this manure is applied as a fertilizer, pesticides can contaminate plant-soil systems. Few studies have focused on pesticide infiltration from applying pesticide-contaminated manure to land. In this study, the fate of pesticide vanisulfane from chicken manure was studied in radish-soil and cabbage-soil systems assisted by carbon-14 labeling. Vanisulfane and its metabolites mostly appeared as bound residues (BRs) after introduction, and BR release was found at 35 d. Notably, manure contaminated with vanisulfane and its metabolites exhibited higher plant accumulation and phytotoxicity than manure contaminated with only the parent. Four metabolites were identified, and germination toxicity assays illustrated that a metabolite with an aldehyde structure induced phytotoxicity. This study provides valuable information on pesticide contamination from manure and emphasizes the importance of considering pesticide metabolites when assessing environmental risks.

Understanding the metabolism of the novel plant antiviral agent dufulin by different positional 14C labeling in cherry radishes.

Dufulin is a new type of plant antiviral agent. However, its metabolism in plants, which is very important for environmental risk assessment, is still unclear. In this study, we used 14C markers at different positions and high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (HPLC-QTOF-MS) to qualitatively and quantitatively analyze dufulin metabolites in cherry radish. By combining ion pairs with unique abundance ratios, we clarified the metabolite structures, inferred the metabolic pathway of dufulin, and clarified the criteria for residues. The extractable residue of dufulin from cherry radish stem and leaf tissues was above 98 % and that in the succulent root was above 87 %. In the stem and leaf tissues and succulent root, dufulin underwent both phase I and phase II metabolism, and four metabolites were produced, including a conjugate of glucose malonate and hydroxylated dufulin, which was confirmed by comparison with a standard. However, the proportions and concentrations of the four metabolites did not meet the residue criteria, so only the dufulin precursor compound was included as a residue. This study provides reliable data for evaluating the impacts of dufulin on the environment and human health and for objectively examining the safety of dufulin.

Accumulation and biotransformation of the novel vanillin-derived pesticide, vanisulfane, in laying hens after dietary exposure.

Vanisulfane is a novel plant antiviral agent with promising prospects to prevent and control viral crop diseases. However, human health risk assessment after vanisulfane exposure from animal-derived food products remains limited. To gain insight into the accumulation and biotransformation of vanisulfane in livestock, laying hens were dietary exposed to 14C-vanisulfane. Although more than 80 % of the applied dose was observed in the excreta, vanisulfane and its metabolites accumulated in tissues, especially the liver and kidney, and was found to be transferred to eggs. A total of eight metabolites associated with both phase I and phase II metabolism were identified via 14C tracing and LC-QTOF-MS. Phase I metabolism included oxidation, hydroxylation, dechlorination and demethylation, and phase II metabolism was associated with sulfonic acid and glucuronide conjugation. The high percentages of metabolites in laying hens' tissues and organs, illustrated the active biotransformation of vanisulfane in vivo, which suggests that the marker residues of vanisulfane should consider its major metabolites. A digestive model was also used to determine the digestive fate of vanisulfane. This study improves our understanding of vanisulfane accumulation and biotransformation in laying hens, which will be helpful for risk assessments of foods derived from animals exposed to pesticides.

Nonstereoselective behavior of novel chiral organophosphorus pesticide Dufulin in cherry radish by different absorption methods.

Dufulin is a biologically derived antiviral agent chemically synthesized by α-phosphoramidate in sheep and is effective against viral diseases in plants such as tobacco, rice, cucumber and tomato. However, the environmental behaviors and fate of Dufulin under different cultivation systems remain unknown. This study investigates the absorption, translocation and accumulation of 14C-Dufulin stereoisomers introduced by pesticide leaf daubing and by mixing the pesticide with soil in different tissues of cherry radish. We particularly focused on whether the behaviors of Dufulin enantiomers in plants were stereoselective. In the leaf uptake experiments, S-Dufulin and R-Dufulin were transported both up and down, while more than 93% of the pesticide remained in the labeled leaves. During the radicular absorption experiments, both enantiomers of Dufulin were taken up by radish roots and moved to the upper part of the plant, while less than 0.2% Dufulin was absorbed from the soil. Hence, it was easier for Dufulin to enter plants through the leaf surface than through the roots. However, we found in this trial that the stereoisomers of Dufulin underwent nonstereoselective absorption and translocation, which implies that rac-Dufulin and its metabolites should be a major research priority. Overall, our results provide a relatively accurate prediction of the risk assessment of Dufulin, which will help guide its rational use in the environment as well as ensure eco-environmental safety and human health.

Diverse positional 14C labeling-assisted metabolic analysis of pesticides in rats: The case of vanisulfane, a novel vanillin-derived pesticide.

Information on pesticide metabolites is crucial for accurate environmental risk assessment. However, identifying the various metabolites of a novel pesticide is challenging since the potential metabolic pathways are unknown. In this study, we coupled diverse positional 14C labeling with high-resolution mass spectrometry to quantitatively and qualitatively study pesticide metabolism in rats. With the unique M/(M + 2) ratios derived from 14C, precursor compounds of metabolites could be better distinguished from impurity ions. Additionally, the use of diverse 14C labeling positions is a powerful tool to elucidate the complete metabolic fate of novel contaminants. Vanisulfane is a novel vanillin-derived antiviral agent with encouraging prospects for the efficient control of cucumber mosaic virus in China, but its metabolic pathways in mammals are still poorly understood. Thus, the metabolism of vanisulfane was studied in rats of both sexes by this strategy. The results showed that phase I and phase II metabolism occurred in both sexes. The former included mainly oxidation reactions, and the latter involved binding reactions that formed glucuronide, sulfate and amino acid conjugates. Sex-related differences were observed in the experiment, with earlier appearance of downstream metabolites and a preference for sulfate conjugate formation in males compared to females. This research facilitates the risk evaluation of vanisulfane, and offers an effective framework for screening unknown pesticide metabolic pathways, which could be applied to establish the metabolic profiles of other novel contaminants with limited information.

Translocation and metabolism of the chiral neonicotinoid cycloxaprid in oilseed rape (Brassica napus L.).

Neonicotinoids have been banned in some countries because of increased nontarget resistance and ecological toxicity. Cycloxaprid is a potentially promising substitute, but its metabolism in plants is still poorly understood. The study aims to clarify the translocation of cycloxaprid, identify its metabolites, propose possible metabolic pathways and compare differences between enantiomers in oilseed rape via 14C tracing technology and HPLC-QTOF-MS. The results showed that most cycloxaprid remained in the treated leaves, and only a small amount translocated to the anthers. Seven metabolites were identified, and the possible metabolic pathway was divided into two phases. Phase Ⅰ metabolism included two metabolites obtained via cleavage of the oxa-bridged seven-membered ring. Phase II metabolism was responsible for glucose conjugate formation. The possible metabolic pathways revealed that the proportion of phase I metabolites gradually decreased over time, and the phase II metabolites transformed from monosaccharide and disaccharide conjugates to trisaccharide and tetrasaccharide conjugates. The levels of metabolites were significantly different between the enantiomers. In particular, the main metabolite was M4, which has confirmed biological toxicity. M2 was the only metabolite detected in rapeseed. The results will promote the scientific application of cycloxaprid in agriculture and could have implications for assessing environmental risk.

Sex-related deposition and metabolism of vanisulfane, a novel vanillin-derived pesticide, in rats and its hepatotoxic and gonadal effects.

A series of vanillin derivatives have recently been synthesized as effective candidate antiviral agents, with vanisulfane exhibiting pronounced curative and protective activities against cucumber mosaic virus and potato virus Y. However, research on some new pesticides usually ignores their various metabolites and sex-related toxicity. Assisted by 14C labeling, a trial was conducted to investigate the tissue distribution, excretion, and metabolism of vanisulfane in male and female rats for the first time. The results showed that 83.30-87.51% of applied 14C activity was excreted in urine and feces within 24 h of oral administration, and 14C was most abundant in the liver and kidney in both sexes. Interestingly, sex differences were observed in the experiment, with lower body clearance in males than in females 24 h after treatment and preferences for biliary and renal excretion of the pesticide in male and female rats, respectively. A high degradation rate was found for vanisulfane in the plasma; thus, the metabolites of vanisulfane were investigated using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with 14C labeling. One glucuronic acid conjugate and two oxidation metabolites were detected, supporting the monitoring of vanisulfane in vivo. Additionally, rats exposed to vanisulfane exhibited hepatic steatosis in both sexes, along with mild gonadal effects in males. This research offers an effective method for conducting environmental behavioral research and provides new insights for evaluating the potential risks of novel pesticides in mammals from a sex perspective.

Characterization and mitigation of aerosols and spatters from ultrasonic scalers.

BACKGROUND: Dental procedures often produce aerosols and spatter, which have the potential to transmit pathogens such as severe acute respiratory syndrome coronavirus 2. The existing literature is limited. METHODS: Aerosols and spatter were generated from an ultrasonic scaling procedure on a dental manikin and characterized via 2 optical imaging methods: digital inline holography and laser sheet imaging. Capture efficiencies of various aerosol mitigation devices were evaluated and compared. RESULTS: The ultrasonic scaling procedure generated a wide size range of aerosols (up to a few hundred µm) and occasional large spatter, which emit at low velocity (mostly < 3 m/s). Use of a saliva ejector and high-volume evacuator (HVE) resulted in overall reductions of 63% and 88%, respectively, whereas an extraoral local extractor (ELE) resulted in a reduction of 96% at the nominal design flow setting. CONCLUSIONS: The study results showed that the use of ELE or HVE significantly reduced aerosol and spatter emission. The use of HVE generally requires an additional person to assist a dental hygienist, whereas an ELE can be operated hands free when a dental hygienist is performing ultrasonic scaling and other operations. PRACTICAL IMPLICATIONS: An ELE aids in the reduction of aerosols and spatters during ultrasonic scaling procedures, potentially reducing transmission of oral or respiratory pathogens like severe acute respiratory syndrome coronavirus 2. Position and airflow of the device are important to effective aerosol mitigation.

Droplet evaporation residue indicating SARS-COV-2 survivability on surfaces.

We conducted a systematic investigation of droplet evaporation on different surfaces. We found that droplets formed even with distilled water do not disappear with evaporation but instead shrink to a residue of a few micrometers lasting over 24 h. The residue formation process differs across surfaces and humidity levels. Specifically, under 40% relative humidity, 80% of droplets form residues on plastic and uncoated and coated glass, while less than 20% form on stainless steel and none on copper. The formation of residues and their variability are explained by modeling the evaporation process considering the presence of nonvolatile solutes on substrates and substrate thermal conductivity. Such variability is consistent with the survivability of SARS-CoV-2 measured on these surfaces. We hypothesize that these long-lasting microscale residues can potentially insulate the virus against environmental changes, allowing them to survive and remain infectious for extended durations.

Risk assessment of airborne transmission of COVID-19 by asymptomatic individuals under different practical settings.

The lack of quantitative risk assessment of airborne transmission of COVID-19 under practical settings leads to large uncertainties and inconsistencies in our preventive measures. Combining in situ measurements and computational fluid dynamics simulations, we quantify the exhaled particles from normal respiratory behaviors and their transport under elevator, small classroom, and supermarket settings to evaluate the risk of inhaling potentially virus-containing particles. Our results show that the design of ventilation is critical for reducing the risk of particle encounters. Inappropriate design can significantly limit the efficiency of particle removal, create local hot spots with orders of magnitude higher risks, and enhance particle deposition causing surface contamination. Additionally, our measurements reveal the presence of a substantial fraction of faceted particles from normal breathing and its strong correlation with breathing depth.

Risk assessment of airborne transmission of COVID-19 by asymptomatic individuals under different practical settings.

The lack of quantitative risk assessment of airborne transmission of COVID-19 under practical settings leads to large uncertainties and inconsistencies in our preventive measures. Combining in situ measurements and numerical simulations, we quantify the exhaled particles from normal respiratory behaviors and their transport under elevator, small classroom and supermarket settings to evaluate the risk of inhaling potentially virus-containing particles. Our results show that the design of ventilation is critical for reducing the risk of particle encounters. Inappropriate design can significantly limit the efficiency of particle removal, create local hot spots with orders of magnitude higher risks, and enhance particle deposition causing surface contamination. Additionally, our measurements reveal the presence of substantial fraction of crystalline particles from normal breathing and its strong correlation with breathing depth.

Machine learning holography for 3D particle field imaging.

We propose a new learning-based approach for 3D particle field imaging using holography. Our approach uses a U-net architecture incorporating residual connections, Swish activation, hologram preprocessing, and transfer learning to cope with challenges arising in particle holograms where accurate measurement of individual particles is crucial. Assessments on both synthetic and experimental holograms demonstrate a significant improvement in particle extraction rate, localization accuracy and speed compared to prior methods over a wide range of particle concentrations, including highly dense concentrations where other methods are unsuitable. Our approach can be potentially extended to other types of computational imaging tasks with similar features.