A computational and experimental study of cis-trans isomeric pesticides based on collision-induced dissociation of high-resolution mass spectrometry.

RATIONALE: Pesticide isomers are widely available in agricultural production and may vary widely in biological activity, potency, and toxicity. Chromatographic and mass spectrometric analysis of pesticide isomers is challenging due to structural similarities. METHODS: Based on liquid chromatography time-of-flight mass spectrometry, identification of cis-trans isomeric pesticides was achieved through retention time, characteristic fragment ions, and relative abundance ratio. Furthermore, theoretical and basic research has been conducted on the differences in characteristic fragment ions and their relative abundance ratios of cis-trans isomers. On the one hand, the cleavage pathways of six cis-trans isomers were elucidated through collision-induced dissociation to explain different fragment ions of the isomers. On the other hand, for those with the same fragment ions but different abundance ratios, energy-resolved mass spectrometry combined with computational chemical density functional theory in terms of kinetics, thermodynamics, and bond lengths was employed to explain the reasons for the differences in characteristic fragment ions and their abundance ratios. RESULTS: A high-resolution mass spectrometry method was developed for the separation and analysis of cis-trans isomers of pesticides in traditional Chinese medicine Radix Codonopsis, and six pesticide isomers were distinguished by retention time, product ions, and relative abundance ratios. The limits of quantification of the six pesticides were up to 10 µg/kg, and the linear ranges of them were 10-200 µg/kg, with coefficients of determination (R2) > 0.99, which demonstrated the good linearity of the six pesticides. The recoveries of the pesticides at spiked concentrations of 10, 20, and 100 µg/kg reached 70-120% with relative standard deviations ≤20%. CONCLUSIONS: It was demonstrated that the application of the method was well suited for accurate qualitative and quantitative analysis for isomers with different structures, which could avoid false-negative results caused by ignoring other isomers effectively.

Thermochemical and Kinetic Investigation of Pentanol Oxidation Initiated by Hydrogen, Methyl, Hydroxyl, and Hydroperoxyl Radicals.

n-Pentanol is acknowledged as a prospective alternative and a supplement to traditional fossil fuels. H-abstraction reaction assumes a pivotal role in initiating the chain reaction during n-pentanol combustion. To investigate the oxidation characteristics of n-pentanol, the composite quantum chemical methods CBS-QB3 and G4 are employed to obtain thermochemical and kinetic parameters in the H-abstraction reaction of n-pentanol. The calculated isobaric heat capacity provides accurate predictions of the experimental results. Branching ratios underscore that H-abstraction at the Cα site serves as the primary channel between n-pentanol and H/CH3/È®H2. For the reaction between n-pentanol and È®H, the Cß site emerges as the most favorable channel due to the significant variational effect. The overall rate coefficient for H-abstraction from n-pentanol by È®H radicals is expressed as k = 3565.11 × T2.93 exp (1465.44/T) (cm3 mol-1 s-1), and the data obtained at the CBS-QB3 level demonstrate good agreement with experimental observations. Furthermore, the original model is modified based on current results, and the improved model demonstrates superior predictive capabilities for jet-stirred reactor (JSR) data and ignition delay times. Reaction path and sensitivity analyses are employed to identify fuel consumption pathways and critical reactions in the combustion of n-pentanol.

Quercetin improves diabetic kidney disease by inhibiting ferroptosis and regulating the Nrf2 in streptozotocin-induced diabetic rats.

Diabetic kidney disease (DKD) is a leading factor in end-stage renal disease. The complexity of its pathogenesis, combined with the limited treatment efficacy, necessitates deeper insights into potential causes. Studies suggest that ferroptosis-driven renal tubular damage contributes to DKD's progression, making its counteraction a potential therapeutic strategy. Quercetin, a flavonoid found in numerous fruits and vegetables, has demonstrated DKD mitigation in mouse models, though its protective mechanism remains ambiguous. In this study, we delved into quercetin's potential anti-ferroptotic properties, employing a DKD rat model and high glucose (HG)-treated renal tubular epithelial cell models. Our findings revealed that HG prompted unusual ferroptosis activation in renal tubular epithelial cells. However, quercetin counteracted this by inhibiting ferroptosis and activating NFE2-related factor 2 (Nrf2) expression in both DKD rats and HG-treated HK-2 cells, indicating its renal protective role. Further experiments, both in vivo and in vitro, validated that quercetin stimulates Nrf2. Thus, our research underscores quercetin's potential in DKD treatment by modulating the ferroptosis process via activating Nrf2 in a distinct DKD rat model, offering a fresh perspective on quercetin's protective mechanisms.

Scientific Machine Learning of 2D Perovskite Nanosheet Formation.

We apply a scientific machine learning (ML) framework to aid the prediction and understanding of nanomaterial formation processes via a joint spectral-kinetic model. We apply this framework to study the nucleation and growth of two-dimensional (2D) perovskite nanosheets. Colloidal nanomaterials have size-dependent optical properties and can be observed in situ, all of which make them a good model for understanding the complex processes of nucleation, growth, and phase transformation of 2D perovskites. Our results demonstrate that this model nanomaterial can form through two processes at the nanoscale: either via a layer-by-layer chemical exfoliation process from lead bromide nanocrystals or via direct nucleation from precursors. We utilize a phenomenological kinetic analysis to study the exfoliation process and scientific machine learning to study the direct nucleation and growth and discuss the circumstances under which it is more appropriate to use phenomenological or more complex machine learning models. Data for both analysis techniques are collected through in situ spectroscopy in a stopped flow chamber, incorporating over 500,000 spectra taken under more than 100 different conditions. More broadly, our research shows that the ability to utilize and integrate traditional kinetics and machine learning methods will greatly assist in the understanding of complex chemical systems.

Allograft inflammatory factor-1 enhances inflammation and oxidative stress via the NF-κB pathway in diabetic kidney disease.

Inflammation and glomerular endothelial dysfunction promote diabetic kidney disease (DKD) progression, but the mechanisms are not fully understood. Allograft inflammatory factor-1 (AIF-1) is a protein that regulates inflammatory reactions and immune responses. This study aimed to explore the mechanism of AIF-1 in a DKD animal model and mouse renal glomerular endothelial cells (MRGECs). We injected AIF-1-shRNA into the tail vein to knockdown AIF-1 in db/db mice. Metabolic index, renal pathological changes and inflammatory factors were measured in each group. Lentiviral transfection was used to overexpress AIF-1 in MRGECs. Inflammatory factors, oxidative stress and nuclear factor-κB (NF-κB) pathway-related proteins were examined. AIF-1 expression was upregulated in glomerular endothelial cells in renal tissues of db/db mice. Knockdown of AIF-1 reversed kidney injury and renal inflammation in db/db mice. In a 30 mM high-glucose environment, overexpression of AIF-1 in MRGECs activated the NF-κB pathway and induced inflammation and oxidative stress. Moreover, this damage could be attenuated by the addition of an NF-κB inhibitor (BAY 11-7082). In conclusion, AIF-1 facilitates glomerular endothelial cell inflammation and oxidative stress in DKD via the NF-κB signaling pathway. Our results provide evidence for the molecular mechanism of DKD and may offer a potential target for DKD treatment.

Spin-induced linear polarization of photoluminescence in antiferromagnetic van der Waals crystals.

Antiferromagnets are promising components for spintronics due to their terahertz resonance, multilevel states and absence of stray fields. However, the zero net magnetic moment of antiferromagnets makes the detection of the antiferromagnetic order and the investigation of fundamental spin properties notoriously difficult. Here, we report an optical detection of Néel vector orientation through an ultra-sharp photoluminescence in the van der Waals antiferromagnet NiPS3 from bulk to atomically thin flakes. The strong correlation between spin flipping and electric dipole oscillator results in a linear polarization of the sharp emission, which aligns perpendicular to the spin orientation in the crystal. By applying an in-plane magnetic field, we achieve manipulation of the photoluminescence polarization. This correlation between emitted photons and spins in layered magnets provides routes for investigating magneto-optics in two-dimensional materials, and hence opens a path for developing opto-spintronic devices and antiferromagnet-based quantum information technologies.

Real-world medication persistence among HIV-1 patients initiating integrase inhibitor-based antiretroviral therapy in Japan.

INTRODUCTION: Medication persistence has rarely been studied for integrase strand transfer inhibitor (INSTI)-based regimens among patients living HIV (PLWH) in Asia. This study investigated medication persistence for newly prescribed INSTI-based regimens in Japan by comparing single-tablet regimens (STRs) versus multiple-tablet regimens (MTRs), based on the Medical Data Vision database. METHODS: Adult PLWH with ≥2 claims for antiretroviral therapy (ART) of interest between 1 January 2017 and 30 June 2018 were included if they had a ≥3-month continuous enrolment prior to the index date and a ≥6-month follow-up after the index date. Medication persistence was measured as the duration from initiation to discontinuation of the prescribed INSTI-based regimen. RESULTS: Overall, 487 patients were included, with 220 in the STR cohort and 267 in the MTR cohort. Persistence was longer in the STR cohort than in the MTR cohort (mean days on the index regimens: 384.2 vs. 317.3, P < 0.001). MTRs were associated with a higher risk of discontinuation than STRs (hazard ratio [HR], 1.72; 95% confidence interval [CI], 1.18-2.52; P = 0.005). Other factors that were associated with discontinuation were backbone (emtricitabine/tenofovir disoproxil fumarate vs. emtricitabine/tenofovir alafenamide: HR, 5.64; 95% CI, 3.68-8.66; P < 0.001), third agent (raltegravir vs. elvitegravir/cobicistat: HR, 2.06; 95% CI, 1.10-3.86; P = 0.024), age (HR, 1.02; 95% CI, 1.01-1.03; P = 0.007), and the number of non-ART index medications (HR, 1.16; 95% CI, 1.12-1.21; P < 0.001). CONCLUSIONS: Among PLWH newly prescribed an INSTI-based regimen in Japan, STRs were associated with longer persistence than MTRs.

Spontaneous Polarity Flipping in a 2D Heterobilayer Induced by Fluctuating Interfacial Carrier Flows.

Polarity often refers to the charge carrier type of a semiconductor or the charging state of a functional group, generally dominating their functionality and performance. Herein we uncover a spontaneous and stochastic polarity-flipping phenomenon in monolayer WSe2, which randomly switches between the n-type and p-type states and is essentially triggered by fluctuating carrier flows from or to the adjacent WS2 monolayer. We have traced such fluctuating carrier flows by interfacial photocurrent measurements in a zero-bias two-terminal device. Such polarity flipping results in switching between the negative and positive correlations between the emission intensities of WS2 and WSe2 in the heterobilayer, which is further well-controlled by the electrostatic gate-tuning experiments in a capacitor-structure device. Our work not only demonstrates giant and intermittent carrier flows through long-range coupling in 2D heterostructures and a consequent spontaneous polarity flipping phenomenon but also provides a two-emitter system with a switchable correlation sign that could project future applications in optical logic devices.

Biphasic Functions of Sodium Fluoride (NaF) in Soft and in Hard Periodontal Tissues.

Sodium fluoride (NaF) is widely used in clinical dentistry. However, the administration of high or low concentrations of NaF has various functions in different tissues. Understanding the mechanisms of the different effects of NaF will help to optimize its use in clinical applications. Studies of NaF and epithelial cells, osteoblasts, osteoclasts, and periodontal cells have suggested the significant roles of fluoride treatment. In this review, we summarize recent studies on the biphasic functions of NaF that are related to both soft and hard periodontal tissues, multiple diseases, and clinical dentistry.

The Potential Roles of Dec1 and Dec2 in Periodontal Inflammation.

Periodontal inflammation is a common inflammatory disease associated with chronic inflammation that can ultimately lead to alveolar attachment loss and bone destruction. Understanding autophagy and pyroptosis has suggested their significant roles in inflammation. In recent years, studies of differentiated embryo-chondrocyte expressed genes 1 and 2 (Dec1 and Dec2) have shown that they play important functions in autophagy and in pyroptosis, which contribute to the onset of periodontal inflammation. In this review, we summarize recent studies on the roles of clock genes, including Dec1 and Dec2, that are related to periodontal inflammation and other diseases.

[Allergen Analysis of 4622 Children with Allergic Diseases in Shaanxi Province].

OBJECTIVE: To study the distributional characteristics of allergens in children with allergic diseases in Shaanxi province. METHODS: A total of 4 622 children diagnosed with allergic diseases in the Asthma Center, Department of Pediatrics, Xijing Hospital from March 2015 to February 2019 were selected. Serum allergen-specific immunoglobulin E (sIgE) of 19 common kinds of allergens were examined with enzyme-linked immunosorbent assay (ELISA). The children were divided into different groups according to sex, age and geographical regions, and the distributional characteristics of allergens of the different groups were compared. RESULTS: The overall positive rate for the 19 allergens of the 4 622 children was 62.8%. The ranking of the positive rates for individual allergens from high to low were as follows: 24.2% for milk, 18.0% for mold mix, 16.7% for dog dander, 16.4% for house dust mite, 11.7% for cat dander, 10.7% for cashew, 10.6% for weed pollen, 8.8% for egg white, 7.8% for house dust, 7.7% for tree pollen, 5.6% for amaranth, 4.9% for mulberry tree, 3.6% for mango, 3.2% for beef, 2.8% for cockroach, 2.1% for crab, 1.5% for shrimp, 0.8% for pineapple, and 0.3% for shellfish. Analysis based on sex showed that the allergen positive rates in boys were higher than those in girls. Analysis by age difference showed that generally the positive rates for inhaled allergens increased along with the increase in patient age, while the positive rates for ingested allergens decreased along with the increase in patient age. Analysis by geographical regions showed that the positive rate of house dust mite in the patients from the southern part of Shaanxi, the positive rate of weed pollen in the patients from the northern part of Shaanxi and the positive rates of milk and egg white in the patients from the central part of Shaanxi were higher than those in other areas. The cluster analysis and correlation analysis showed that the 19 allergens could be roughly divided into 4 categories. There were moderate correlations among tree pollen, mulberry tree and amaranth. There were moderate correlations among mulberry tree, mango and amaranth. There was moderate correlation between shrimp and crab, and there were mild or weak correlations among most of the other allergens. CONCLUSION: Among the 4 622 children with allergic diseases in Shaanxi Province who were treated in the Asthma Center, Department of Pediatrics, Xijing Hospital, male patients showed higher sensitivity to allergens. The positive rates of inhaled allergens increased, while the positive rates of ingested allergens decreased with increase in patient age. There were regional differences in the distribution of allergens. Some allergens were correlated with each other, which may be related to cross-reaction.

[Heart sound classification based on sub-band envelope and convolution neural network].

Automatic classification of heart sounds plays an important role in the early diagnosis of congenital heart disease. A kind of heart sound classification algorithms based on sub-band envelope feature and convolution neural network was proposed in this paper, which did not need to segment the heart sounds according to cardiac cycle accurately. Firstly, the heart sound signal was divided into some frames. Then, the frame level heart sound signal was filtered with Gammatone filter bank to obtain the sub-band signals. Next, the sub-band envelope was extracted by Hilbert transform. After that, the sub-band envelope was stacked into a feature map. Finally, type Ⅰ and type Ⅱ convolution neural network were selected as classifier. The result shown that the sub-band envelope feature was better in type Ⅰ than type Ⅱ. The algorithm is tested with 1 000 heart sound samples. The test results show that the overall performance of the algorithm proposed in this paper is significantly improved compared with other similar algorithms, which provides a new method for automatic classification of congenital heart disease, and speeds up the process of automatic classification of heart sounds applied to the actual screening.

Elucidating the Weakly Reversible Cs-Pb-Br Perovskite Nanocrystal Reaction Network with High-Throughput Maps and Transformations.

Advances in automation and data analytics can aid exploration of the complex chemistry of nanoparticles. Lead halide perovskite colloidal nanocrystals provide an interesting proving ground: there are reports of many different phases and transformations, which has made it hard to form a coherent conceptual framework for their controlled formation through traditional methods. In this work, we systematically explore the portion of Cs-Pb-Br synthesis space in which many optically distinguishable species are formed using high-throughput robotic synthesis to understand their formation reactions. We deploy an automated method that allows us to determine the relative amount of absorbance that can be attributed to each species in order to create maps of the synthetic space. These in turn facilitate improved understanding of the interplay between kinetic and thermodynamic factors that underlie which combination of species are likely to be prevalent under a given set of conditions. Based on these maps, we test potential transformation routes between perovskite nanocrystals of different shapes and phases. We find that shape is determined kinetically, but many reactions between different phases show equilibrium behavior. We demonstrate a dynamic equilibrium between complexes, monolayers, and nanocrystals of lead bromide, with substantial impact on the reaction outcomes. This allows us to construct a chemical reaction network that qualitatively explains our results as well as previous reports and can serve as a guide for those seeking to prepare a particular composition and shape.

Direct Observation of Symmetry-Dependent Electron-Phonon Coupling in Black Phosphorus.

Electron-phonon coupling in two-dimensional nanomaterials plays a fundamental role in determining their physical properties. Such interplay is particularly intriguing in semiconducting black phosphorus (BP) due to the highly anisotropic nature of its electronic structure and phonon dispersions. Here we report the direct observation of symmetry-dependent electron-phonon coupling in BP by performing the polarization-selective resonance Raman measurement in the visible and ultraviolet regimes, focusing on the out-of-plane Ag1 and in-plane Ag2 phonon modes. Their intrinsic resonance Raman excitation profiles (REPs) were extracted and quantitatively compared. The in-plane Ag2 mode exhibits remarkably strong resonance enhancement across the excitation wavelengths when the excitation polarization is parallel to the armchair (Ag2//AC) direction. In contrast, a dramatically weak resonance effect was observed for the same mode with the polarization parallel to zigzag (Ag2//ZZ) direction and for the out-of-plane Ag1 mode (Ag1//AC and Ag1//ZZ). Analysis on quantum perturbation theory and first-principles calculations on the anisotropic electron distributions in BP demonstrated that electron-phonon coupling considering the symmetry of the involved excited states and phonon vibration patterns is responsible for this phenomenon. Further analysis of the polarization-dependent REPs for Ag phonons allows us to resolve the existing controversies on the physical origin of Raman anomaly in BP and its dependence on excitation energy, sample thickness, phonon modes, and crystalline orientation. Our study gives deep insights into the underlying interplay between electrons and phonons in BP and paves the way for manipulating the electron-phonon coupling in anisotropic nanomaterials for future device applications.

Superstrong and Tough Hydrogel through Physical Cross-Linking and Molecular Alignment.

Hydrogels are attracting increasing attention due to their potential use in various fields. However, most of the existing hydrogels have limitations in either dissipating mechanical energy or maintaining high stretchability under deformation, thus do not possess high mechanical properties. Herein, poly(vinyl alcohol) (PVA)-tannic acid (TA) hydrogels with both high mechanical strength and stretchability were obtained via a step-by-step physical cross-linking and molecular alignment method. Saline-triggered physical interactions serve as "sacrifice domains" to dissipate energy and endow PVA-based hydrogel with high mechanical strength (≈16 MPa) and stretchability (≈1000%). Due to the reversible arranging and disassociating property of physical interactions, PVA-TA hydrogels show excellent shape memory performance. We further demonstrated an effective approach to fabricate strong and aligned PVA-TA thread. The resultant well-aligned PVA-TA dry thread reveals an ultrahigh mechanical tensile strength of up to 750 MPa, nearly 45 times higher than PVA-TA thread with no alignment. Wide-angle X-ray two-dimensional diffraction images further confirmed the alignment of PVA fibers in stretching direction. In addition, we applied the PVA-TA hydrogel as suture and evaluated the cytotoxicity and biocompatibility of the PVA-TA suture.

Antibacterial Activity of Nitric Oxide-Releasing Hyperbranched Polyamidoamines.

Hyperbranched polyamidoamines (h-PAMAM) were prepared using a one-pot reaction to have similar molecular weight to third generation PAMAM (G3-PAMAM) dendrimers, and then functionalized with N-diazeniumdiolate nitric oxide (NO) donors. A wide range of NO storage capacities (∼1-2.50 µmol mg-1) and NO-release kinetics (t1/2 ∼30-80 min) were achieved by changing the extent of propylene oxide (PO) modification. The therapeutic potential of these materials was evaluated by studying their antibacterial activities and toxicity against common dental pathogens and human gingival fibroblast cells, respectively. Our results indicate that the combination of NO release and PO modification is necessary to yield h-PAMAM materials with efficient bactericidal action without eliciting unwarranted cytotoxicity. Of importance, NO-releasing PO-modified h-PAMAM polymers exhibited comparable biological properties (i.e., antibacterial action and cytotoxicity) to defect-free G3-PAMAM dendrimers, but at a substantially lower synthetic burden.

Gate-Tunable Resonant Raman Spectroscopy of Bilayer MoS2.

The gate-tunable phonon properties in bilayer MoS2 are shown to be dependent on excitation energy. Raman intensity, Raman shift, and linewidth are affected by resonant excitation, while a nonresonant laser does not influence the intensity significantly. The gate-dependent Raman shift of A1g mode (either blue-, red-, or no-shift) is a result of the combined effect of antibonding electron and resonant-related decoupling effect. Although the decoupling effect cannot be directly measured due to the resonant background, it can be indirectly and qualitatively probed by observing A1g mode. This study on gate-tunable resonant Raman spectroscopy has clarified the influence of carrier doping on phonon properties and demonstrates a new degree of freedom in manipulating phonons in 2D material systems.

Ultrafast Photogenerated Hole Extraction/Transport Behavior in a CH3 NH3 PbI3 /Carbon Nanocomposite and Its Application in a Metal-Electrode-Free Solar Cell.

Aligned and flexible electrospun carbon nanomaterials are used to synthesize carbon/perovskite nanocomposites. The free-electron diffusion length in the CH3 NH3 PbI3 phase of the CH3 NH3 PbI3 /carbon nanocomposite is almost twice that of bare CH3 NH3 PbI3 , and nearly 95 % of the photogenerated free holes can be injected from the CH3 NH3 PbI3 phase into the carbon nanomaterial. The exciton binding energy of the composite is estimated to be 23 meV by utilizing temperature-dependent optical absorption spectroscopy. The calculated free carriers increase with increasing total photoexcitation density, and this broadens the potential of this material for a broad range of optoelectronics applications. A metal-electrode-free perovskite solar cell (power conversion efficiency: 13.0 %) is fabricated with this perovskite/carbon composite, which shows great potential for the fabrication of efficient, large-scale, low-cost, and metal-electrode-free perovskite solar cells.

Synthesis, Structure, Band Gap, and Near-Infrared Photosensitivity of a New Chalcogenide Crystal, (NH4)4Ag12Sn7Se22.

A new chalcogenide crystal, (NH4)4Ag12Sn7Se22 (FJSM-STS), has been solvothermally synthesized. The crystal structure, which is composed of arrays of [Sn3Se9]n(6n-) chains interconnecting [SnAg6Se10]n(10n-) and [Ag3Se4]n(5n-) layers, is unprecedented among the reported A/Ag/Sn/Q (A = cation; Q = S, Se, and Te) compounds. Optical absorption together with theoretical calculations of the band structure indicate a direct band gap of 1.21 eV for FJSM-STS, which is close to the ideal band gap to maximize the photoconversion efficiency proposed by Shockley and Queisser. The toxic-metal-free crystal of FJSM-STS exhibits obvious photosensitivity in the near-infrared range. The variates of power and temperature on the photosensitivity have been studied.

Purified plasmonic lasing with strong polarization selectivity by reflection.

As miniaturized light sources of size beyond the optical diffraction limit, surface plasmon lasers are of particular interest for numerous exciting applications. Although convincing demonstrations of plasmonic lasing have been reported with the metal-insulator-semiconductor (MIS) hybrid design using semiconductor nanomaterials, it remains a challenge that conventional photonic lasing may be triggered and misinterpreted as plasmonic lasing. One way to address this issue is to cut off photonic modes in the waveguide by strictly restricting the semiconductor thickness. Here we propose a novel hybrid design, namely the dielectric-metal-insulator-semiconductor (DMIS) design that potentially solves the challenge. Taking advantage of strong polarization selectivity by reflection effect in favor of the plasmonic mode, whispering-gallery mode cavities based on the proposed DMIS design suppress possible photonic lasing modes and relieve the semiconductor thickness for purified plasmonic lasing. Using these cavities, we demonstrate room-temperature purified plasmon lasing with cadmium sulphide square nanobelts atop of a deposited multilayer film. Approaches for further improvement of the plamsonic lasing performance are discussed. Our design provides a reliable platform for developing better surface plasmon nanolasers using new semiconductor nanomaterials.