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As the negative repercussions of environmental devastation, such as air quality decline and air pollution, become more apparent, environmental consciousness is growing across the world, forcing nations to take steps to mitigate the damage. China pledged to achieve air quality improvement goal to combat global environment issue, yet the spatial-temporal differentiation and its driving factors of environment-meteorology-economic index for air quality are not fully analysed. To promote regional collaborative control of air pollution and achieve sustainable urban development, spatial and temporal different and its driving factors of air quality in Shandong Province during 2013-2020. Results revealed that concentrations of sulfur dioxide (SO2), nitrogen dioxide (NO2), particulate matter 2.5 (PM2.5), particulate matter 10 (PM10), and carbon monoxide (CO-95per) exhibited decreasing trend (SO2 concentrations decreasing 84 % and CO-95per concentrations decreasing 90 %). Air quality was improved from inland areas to coastal areas. Pollutant indicators of SO2, NO2, PM10, PM2.5, and CO-95per demonstrated significant positive correlation (P < 0.05). Air temperature and precipitation are significantly negatively correlated with concentrations of SO2, NO2, PM10, PM2.5, and CO-95per but significantly positively correlated with ozone (O3-8 h). SO2, NO2, PM2.5, PM10, CO-95per, and proportion of days with heavy pollution are strongly positively correlated with proportion of secondary industry but strongly negatively correlated with proportion of tertiary industry and volume of household waste. Except for O3-8 h, pollutant index of Provincial Capital Economic Circle (PCEC) and Southern Shandong Economic Circle (SSEC) has significant negative correlation (P < 0.05) with regional gross domestic product and investment in environmental protection; however, investment in environmental protection of Eastern Shandong Economic Circle (ESEC) has no significant correlation with air pollution index. There was significant negative correlation between vegetable sowing area and SSEC pollutant index. The relationship between pollution emission and investment in environmental protection has shifted from high pollution-low investment to low pollution-low investment in PCEC, ESEC and SSEC, and the inflection point was in 2020 for PCEC, 2019 for ESEC, and 2020 for SSEC. Those results provide empirical evidence and theoretical support for the improvement of regional air quality, aiming to achieve high-quality development. According to these findings, it has been found that meteorological elements, pollutant emission, socio-economic factors and agricultural data affect air quality. Those results could provide meaningful and significant supporting for synergistic regulation of diverse pollutants.

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Both nitrogen-doped carbon (NC) and metal-nitrogen-carbon (MNC) materials have been extensively investigated in lithium-sulfur batteries to alleviate the "shuttle effect". MNC are generally synthesized using NC as the parent material, wherein nitrogen atoms in NC serve as the "bridge" to coordinate with metal atoms. So far, an important scientific issue has not been settled: does the introduction of metal sites into NC certainly enhance the Li-S battery performance? In this work, NC and MNC materials derived from the same precursor, a nitrogen-rich porous polymer, are systematically compared as cathode hosts for Li-S battery through theoretical calculations and experimental investigation. Li-S cell with NC as the cathode sulfur host exhibits better cycle performance at low current densities (0.1 and 0.2C), whereas MNC materials predominate at higher current densities (such as 1C and 2C). Based on theoretical calculation and experimental results, it is concluded that the introduction of metal sites into NC through nitrogen bonding promoted the catalytic capability for faster sulfur redox reaction kinetics, whereas the adsorption energy toward polysulfides decreased. This work provides important guidance for more targeted design of advanced materials for lithium-sulfur battery application in the future.

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Introduction: Acute primary angle closure (APAC) is an emergency ophthalmic presentation and a major cause of irreversible blindness in China. However, only a few studies have focused on the characteristics of optic disc hemorrhage (ODH) during an APAC attack, including its shape, depth, location, scope, and duration after intraocular pressure (IOP) control, along with changes in the optic nerve. This study aimed to analyze the characteristics of ODH and optic nerve changes in patients during their first APAC episode. Methods: This retrospective study involved 32 eyes from 32 patients with APAC who received sequential treatment and analyzed the following parameters: the highest IOP and its duration, ODH, retinal nerve fiber layer thickness (RNFLT), and mean deviation (MD). We compared parameters obtained from the affected eye (ODH group) and contralateral unaffected eye (control group), as well as intragroup comparisons. Results: The mean IOP in the ODH group was 64.28 ± 10.36 mmHg, with a duration of 4.44 ± 2.35 days. Flame and splinter shapes accounted for 84.38% of the ODH. The mean ODH duration was 4.81 ± 3.25 weeks. ODH during APAC was isolated to one sector in 59.38% of cases, mostly occurring in the temporal superior and temporal inferior (each accounting for 21.88% of the cases). There was a positive correlation between the extent of hemorrhage and the highest IOP duration (p < 0.001). RNFLT was significantly thickened within 72 h post-IOP control but was thinned by 2 weeks. By 6 months, the thinning stabilized, and there was no difference noted between the ODH and control groups at 12 months. MD partly improved at 6 months post-IOP control, and ODH scope significantly affected the MD (p < 0.001). The duration of high IOP was positively correlated to the ODH scope and MD damage. Discussion: Timely and effective IOP management is essential for recovering visual function following an APAC attack.

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Purpose: To explore stable and sensitive indicators for clinical diagnosis of acute angle closure (AAC) secondary to lens subluxation (LS) through quantitative analysis of CASIA 2 imaging.Design: A prospective cross-sectional study. Methods: Setting: Clinical practice.Participants: 23 patients with unilateral acute angle closure secondary to lens subluxation and 23 cataract patients without lens subluxation were recruited. Lens subluxation was confirmed by ultrasound biomicroscope diagnosis. The contralateral eyes without LS served as fellow control group. The cataract eyes without LS were enrolled in blank control group.Intervention: Participants underwent ophthalmologic examinations including slit-lamp biomicroscope, best corrected visual acuity, intraocular pressure, central corneal thickness measurement, axial length, gonioscopy, ultrasound biomicroscope and 360-degree anterior chamber and crystalline lens scan protocols of CASIA 2 system.Main outcome measures: Automated circumferential anterior segment and lens morphological parameters under anterior segment optical coherence tomography were analyzed via three-dimensional analysis. Results: Significant differences were found in the front and back radius of the lens, the front and back radius of steep curvature of the lens, lens thickness, lens decentration, lens diameter, iris-trabecular contact (ITC) index, ITC area, anterior chamber depth (ACD), lens vault (LV), and iris volume between LS and controls. Among these parameters, LV, the anterior radius of steep curvature of the lens and ACD demonstrated the highest prediction power (AUC = 0.87, 0.89, and 0.86, respectively). The prediction power of tilt/axis was much higher in the Gaussian Naive Bayes model (AUCs = 0.90) than in the logistic model (AUCs = 0.74). Combination of LV_mean, LV_std, tilt and tilt axis in Gaussian Naive Bayes model presented as most stable and excellent diagnostic markers for AAC secondary to LS (AUCs = 0.98). Conclusions: The combination of markers including lens tilt and lens vault in the mathematic model facilitate clinical work as it not only provides novel diagnostic indications and possible prompt treatment for AAC secondary to lens subluxations, but also enhances our understanding of the pathogenic role of zonulopathy in angle closure glaucoma.

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As volatile organic compounds (VOCs), pentamethylbenzene (5-PeMB) and hexamethylbenzene (6-HeMB) are found widely in petroleum and coal tar. Through combustion and industrial generation entering into the atmosphere, they can produce photochemical smog and secondary organic aerosols (SOA) to endanger human health and ecoenvironment eventually. In order to reveal their environmental chemistry, the OH-initiated degradation mechanisms of 5-PeMB and 6-HeMB were studied based on density functional theory (DFT). Result showed that addition pathways were the most favorable with energy barriers of 20.7 and 25.3 kJ/mol, respectively, in the two reactions. The degradation rate constants at 298 K were calculated to be 2.69 × 10-10 and 1.28 × 10-10 cm3 molecule-1 ·s-1, coinciding with the available experimental values. In the presence of OH radicals, the atmospheric lifetimes were estimated to be 2.17 and 2.78 h, respectively, for 5-PeMB and 6-HeMB. According to the quantitative structure-activity relationship (QSAR) model, the toxicity during the degradation process is decreased to fish, daphnia, and green algae.

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Nitrous acid (HONO) is hazardous to the human respiratory system, and the hydrolysis of NO2 is the source of HONO. Hence, the investigation on the removal and transformation of HONO is urgently established. The effects of amide on the mechanism and kinetics of the formation of HONO with acetamide, formamide, methylformamide, urea, and its clusters of the catalyst were studied theoretically. The results show that amide and its small clusters reduce the energy barrier, the substituent improves the catalytic efficiency, and the catalytic effect order is dimer > monohydrate > monomer. Meanwhile, the clusters composed of nitric acid (HNO3), amides, and 1-6 water molecules were investigated in the amide-assisted nitrogen dioxide (NO2) hydrolysis reaction after HONO decomposes by combining the system sampling technique and density functional theory. The study on thermodynamics, intermolecular forces, optics properties of the clusters, as well as the influence of humidity, temperature, atmospheric pressure, and altitude shows that amide molecules promote the clustering and enhance the optical properties. The substituent facilitates the clustering of amide and nitric acid hydrate and lowers the humidity sensitivity of the clusters. The findings will help to control the atmospheric aerosol particle and then reduce the harm of poisonous organic chemicals on human health.

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Objective: Previous laboratory reports implicate heat shock protein (HSP)-specific T-cell responses in glaucoma pathogenesis; here, we aimed to provide direct clinical evidence by correlating systemic HSP-specific T-cell levels with glaucoma severity in patients with primary open-angle glaucoma (POAG). Design: Cross-sectional case-control study. Subjects: Thirty-two adult patients with POAG and 38 controls underwent blood draw and optic nerve imaging. Methods: Peripheral blood monocytes (PBMC) were stimulated in culture with HSP27, α-crystallin, a member of the small HSP family, or HSP60. Both interferon-γ (IFN-γ)+ CD4+ T helper type 1 cells (Th1) and transforming growth factor-ß1 (TGF-ß1)+ CD4+ regulatory T cells (Treg) were quantified by flow cytometry and presented as a percentage of total PBMC counts. Relevant cytokines were measured using enzyme-linked immunosorbent assays. Retinal nerve fiber layer thickness (RNFLT) was measured with OCT. Pearson's correlation (r) was used to assess correlations. Main Outcome Measures: Correlations of HSP-specific T-cell counts, and serum levels of corresponding cytokine levels with RNFLT. Results: Patients with POAG (visual field mean deviation, -4.7 ± 4.0 dB) and controls were similar in age, gender, and body mass index. Moreover, 46.9% of POAG and 60.0% of control subjects had prior cataract surgery (P = 0.48). Although no significant difference in total nonstimulated CD4+ Th1 or Treg cells was detected, patients with POAG exhibited significantly higher frequencies of Th1 cells specific for HSP27, α-crystallin, or HSP60 than controls (7.3 ± 7.9% vs. 2.6 ± 2.0%, P = 0.004; 5.8 ± 2.7% vs. 1.8 ± 1.3%, P < 0.001; 13.2 ± 13.3 vs. 4.3 ± 5.2, P = 0.01; respectively), but similar Treg specific for the same HSPs compared with controls (P ≥ 0.10 for all). Concordantly, the serum levels of IFN-γ were higher in POAG than in controls (36.2 ± 12.1 pg/ml vs. 10.0 ± 4.3 pg/ml; P < 0.001), but TGF-ß1 levels did not differ. Average RNFLT of both eyes negatively correlated with HSP27- and α-crystallin-specific Th1 cell counts, and IFN-γ levels in all subjects after adjusting for age (partial correlation coefficient r = -0.31, P = 0.03; r = -0.52, p = 0.002; r = -0.72, P < 0.001, respectively). Conclusions: Higher levels of HSP-specific Th1 cells are associated with thinner RNFLT in patients with POAG and control subjects. The significant inverse relationship between systemic HSP-specific Th1 cell count and RNFLT supports the role of these T cells in glaucomatous neurodegeneration. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

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Neovascular glaucoma (NVG) is a devastating secondary glaucoma characterized by the appearance of neovascular over the iris and the proliferation of fibrovascular tissue in the anterior chamber angle. Proliferative diabetic retinopathy (PDR) is one of the leading causes of NVG. Currently increasing diabetes population drive the prevalence rate of NVG into a fast-rising lane. The pathogenesis underlying NVG makes it refractory to routine management for other types of glaucoma in clinical practice. The combination of panretinal photocoagulation (PRP), anti-vascular endothelial growth factor (VEGF) injections, anti-glaucoma drugs, surgical intervention as well as blood glucose control is needed. Early diagnosis and aggressive treatment in time are crucial in halting the neovascularization process and preserving vision. This review provides an overview of NVG secondary to diabetic retinopathy (DR), including the epidemiology, pathogenesis and management, so as to provide a better understanding as well as potential therapeutic strategies for future treatment.

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This comment addresses a systematic error in the potential energy surfaces of the title reactions presented in the original article by Alkorta et al. The NO3 radical has D3h symmetry in the electronic ground state while the M08HX functional employed in the original article predicts an incorrect C2v geometry and energy. By combining thermodynamic data for the OH + HNO3 → H2O + NO3 reaction with spectroscopic data and results from M08HX calculations on HNO3, H2O and the OH radical, the ground state NO3 radical energy is estimated to be 37 kJ mol-1 lower than reported for the C2v geometry.

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The presence of chloride ions can facilitate the COD removal efficiency due to the involvement of active chlorine species in the electro-oxidation process, but few attentions have been paid to the negative effect of the electro-generated oxychlorides on electro-oxidation performance. In this study, the effects of oxychlorides were investigated as functions of current density and phenol concentration using DSA anodes in terms of the evaluation of the COD removal performance and the biological toxicity. The results show that oxychlorides formed in the electro-oxidation system could result in the over-evaluation of the COD removal performance. Increasing current density (15-50 mA cm-2) aggravated the over-evaluation of COD removal (4%-18%), owing to the enhancement in the electrochemical generation of oxychlorides. The increase of phenol concentration inhibited the production of oxychlorides, but the effect of oxychlorides on COD values at phenol concentration of 200 mg L-1 (82 mg L-1) was higher than that at 100 mg L-1 (51 mg L-1). The ClO3- was predominantly responsible for over-evaluation of the COD removal. In addition, bioassays with chlorella indicated that the electro-generated oxychlorides significantly increased the biological toxicity of the treated Cl--containing wastewater. This work provides new guidance for the correct evaluation of COD treatment performance and highlight the importance of minimizing toxic inorganic chlorinated byproducts during electro-oxidation of Cl--containing wastewater.

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1,2,3-Trimethylbenzene (1,2,3-TMB) is an important volatile organic compound (VOC) present in petroleum wastewater and the atmosphere. This compound can be degraded by OH radicals via abstraction, addition and substitution mechanisms. Results show that the addition mechanism is dominant and H-abstraction is subdominant, while methyl abstraction and substitution mechanisms are negligible in the gas and aqueous phases. Moreover, H-abstraction products undergo further reactions with O2, NO, NO2, H2O, and OH radicals in the atmosphere. Time-dependent density functional theory (TDDFT) calculations show that the degraded products, including 2,3,4-trimethylphenyl-nitroperoxoite, 1,2,3-trimethyl-4-nitrobenzene, 1,2,3-trimethyl-5-nitrobenzene, 2,6-dimethylbenzyl nitroperoxoite, 2,3-dimethylphenyl nitroperoxoite, 2,6-dimethylbenzaldehyde, and 2,3-dimethylbenzaldehyde, can photolyze under the sunlight. Kinetically, the calculated total rate constant is 5.57 × 10-11 cm3 molecule-1·s-1 at 1 atm and 298 K, which is consistent with available experimental values measured in the atmosphere. In addition, the calculated total reaction rate constant in water is close to that in the gas phase. In terms of ecotoxicity, all degradation products are less toxic than the initial reactant to fish, green algae and daphnia. For mammals represented by rats, 1,2,3-TMB and its products are moderately toxic, except for 2,3-dimethylphenol and 2,6-dimethylphenol, which are slightly toxic.

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Known organophosphorus pesticides are used widely in agriculture to improve the production of crops. Based on the literature, the degradation of some organophosphorus pesticides was studied theoretically. However, the mechanisms and variation of toxicity during the degradation of mevinphos and monocrotophos are still unclear in the environment, especially in wastewater. In this study, the reaction mechanisms for the degradation of the two representative organophosphorus pesticides (i.e., mevinphos and monocrotophos) in presence of OH radicals in the atmosphere and water are proposed using quantum chemical methods wB97-XD/6-311 + +G(3df,2pd)//wB97-XD/6-311 + +G(d,p). Result shows that the dominant channel is OH-addition to the C atom in CC bond with energy barriers being 15.6 and 14.7 kJ/mol, in the atmosphere and water, respectively, for mevinphos. As for monocrotophos, H-abstraction from NH group via barriers of 8.2 and 10.6 kJ/mol is more feasible in both the atmosphere and water. Moreover, the subsequent reactions of the major products in the atmosphere with NO and O2 were also studied to evaluate the atmospheric chemistry of mevinphos and monocrotophos. Kinetically, the total rate constant is 2.68 × 10-9 and 3.86 × 10-8 cm3 molecule-1·s-1 for mevinphos and monocrotophos in the atmosphere and 4.91 × 1010 and 7.77 × 1011 M-1 s-1 in the water at 298 K, thus the lifetime is estimated to be 36.46-364.60 s (2.53-25.31 s) in the atmosphere, and 1.41 × 10-2 - 1.41 × 10-1 s (8.92 ×10-4 - 8.92 ×10-3 s) in the advanced oxidation processes (AOPs) system. Furthermore, ecotoxic predictions for rats and three aqueous organisms imply their toxicity are reduced during degradation by using ECOSAR and T.E.S.T program based quantitative structure and activity relationship (QSAR) method.

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Acephate (O,S-dimethyl acetylphosphoramidothioate) is a typical organophosphorus pesticide used widely in agriculture. It can be released into the atmosphere and water during production and application. In this work, mechanisms in the ·OH initiated degradation of acephate were investigated using quantum chemical methods. Results show that addition, substitution and H-abstraction mechanisms can take place, with the latter being dominant. Moreover, the subsequent reactions of dominant products with O2 and NO in the atmosphere were considered, as well. The rate constant in the atmosphere and aqueous phase was calculated by transition state theory (TST) with the Wigner tunneling contribution. The total rate constant in the atmosphere and aqueous phase is 7.86 × 10-10 and 1.83 × 10-12 cm3 per molecule per s, respectively, the latter being in accordance with the available experimental value of 1.50 × 10-12 cm3 per molecule per s. Moreover, the ecotoxicity of acephate and degradation products was assessed in fish, daphnia, green algae and rats.

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As one of the volatile organic compounds (VOCs) in the environment, 1,2,4,5-tetramethylbenzene (1,2,4,5-TeMB) present in oily wastewater, and it can occur substitution, abstraction, and addition reactions with OH radicals in the atmosphere and wastewater. Electrostatic potential (ESP) and average local ionization energy (ALIE) prediction indicate that H atoms from CH3 group and the benzene ring are the most active sites in 1,2,4,5-TeMB. The result shows that potential energy surfaces (PESs) in the gas and aqueous phase are similar, and the relevant barriers in the latter one are higher. The dominant channel is H abstraction from the benzene ring, and the subdominant one is OH radical addition to the benzene ring. Furthermore, subsequent reactions of dominant products with O2, NO2, NO, and OH radicals in the atmosphere are studied, as well. The total reaction rate constant is calculated to be 2.36×10-10 cm3 molecule-1 s-1 at 1 atm and 298 K in the atmosphere, which agrees well with the experimental data. While the total rate constant in the aqueous phase is much lower than that in the gas phase. Ecologic toxicity analysis shows that 1,2,4,5-TeMB is very toxic to fish, daphnia, and green algae; and OH-initiated degradation in the environment will reduce its toxicity.

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Deliberate addition of mildly oxidative chlorate (ClO3-), so-called "chemical oxygen demand (COD) remover", into wastewater in China or electrochemical production of ClO3- from Cl- induces the false COD reduction, which would bring about false appearance of effluents meeting the COD discharge standards. In this study, an easy sulfite-based reduction method was developed for the first time to remove ClO3- from the water samples before COD determination to eliminate this interference of ClO3-. In this reaction system, keeping the reaction temperature of sulfite reducing ClO3- at 60 °C was crucial for fast ClO3- removal rate, fixed molar [sulfite]ini/[chlorate]ini ratio value and the synchronous exhaustion of sulfite and ClO3-, which were of great significance for the real application of this improved COD determination method. The ClO3- interference on COD determination could be successfully eliminated after 20 min reduction of ClO3- by sulfite at pHini 4.0∼6.0 with the molar [sulfite]ini/[chlorate]ini ratio value in the range of 5∼6 when concentration of ClO3- was below 5 mM. Despite of the involvement of SO4·- in the sulfite reducing ClO3- system, the degradation of organic matters by SO4·- could be greatly impeded due to the lessened dissolved oxygen for SO4·- production at high reaction temperature and the scavenging of SO4·- by sulfite. In this reaction system, ClO2, ClO2- and ClO- were also generated and could be further reduced by sulfite stoichiometrically via oxygen transfer process with Cl- as the final product. In general, this study pioneered an effective, fast and convenient method for COD determination of the ClO3--laden wastewaters and evaluating the real electrochemical wastewater treatment performance in terms of COD removal.

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Glaucoma is a leading cause of blindness worldwide. It is suggested that primary open angle glaucoma (POAG), the most common form of glaucoma, may be associated with significant metabolic alternations, but the systemic literature review and meta-analysis in the area have been missing. Altered metabolomic profiles in the aqueous humor and plasma may serve as possible biomarkers for early detection or treatment targets. In this article, we performed a systematic meta-analysis of the current literature surrounding the metabolomics of patients with POAG and metabolites associated with the disease. Results suggest several metabolites found to be specifically altered in patients with POAG, suggesting broad generalizability and pathways for future research.

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BACKGROUND: Laser peripheral iridotomy (LPI) is effective in primary angle-closure suspects (PACS); however, predictors for anterior segment alterations after LPI are limited. We aimed to evaluate the anterior segment biometric parameters before and after LPI in PACS using the recently developed, CASIA 2 device of anterior segment optical coherence tomography (AS-OCT). METHODS: We performed LPI in 52 PACS. Anterior segment parameters, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber volume (ACV), iris curvature (ICURVE), iridotrabecular contact (ITC), lens vault (LV), lens thickness (LT), radius of the lens, angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) at different distances (i.e., 500 µm from the sclera spur), were evaluated before and after LPI using CASIA 2. RESULTS: Eyes of PACS after LPI had a greater ACV, AOD, ARA, TISA, and TIA, and a lower ITC and ICURVE (all p < 0.001) than those before LPI. On a 360° scan, the anterior chamber angle in the superior quadrant increased the most after the LPI. A higher baseline LT was significantly associated with a greater postoperative increase in AOD 500, ARA 500, TISA 500, and TIA 500 (p = 0.001, p = 0.010, p = 0.004, and p < 0.001, respectively). CONCLUSIONS: We found that LPI widens the anterior chamber angle in the PACS, especially, in the superior quadrant around the iridotomy hole. Eyes with a thicker lens are more likely to experience angle opening because of the LPI.

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Dimetridazole (DMZ) and ornidazole (ONZ) have been widely used to treat anaerobic and protozoal infections. The residues of DMZ/ONZ persist in the water environment. The mechanisms and kinetics of hydroxyl-initiated oxidation, the primary DMZ/ONZ degradation method, were evaluated by quantum chemical methods.·OH-induced degradation of DMZ and ONZ shared many mechanistic and kinetic characteristics. The most feasible degradation pathway involved forming OH-imidazole adducts and NO2. The OH-imidazole adducts were subsequently degraded into double·OH imidazole intermediates. The rate coefficients for·OH degradation of DMZ and ONZ were 4.32 × 109 M-1 s-1 and 4.42 × 109 M-1 s-1 at 298 K, respectively. The lifetimes of DMZ and ONZ treated with·OH at concentrations of 10-9-10-18 mol L-1 at 298 K were τDMZ = 0.231-2.31 × 108 s and τONZ = 0.226-2.26 × 108 s, respectively. Toxicity assessment showed that the first degradation products of DMZ and ONZ exhibited enhanced aquatic toxicity, whereas most of the secondary degradation products were not harmful to aquatic organisms. Some of transformation products were still developmental toxicant or mutagenicity positive.

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The degradation reactions of propylamino and dipropylamino radicals in the presence of NO, NO2 and O2 were investigated at the CCSD(T)/6-311++G (2d, 2p)//B3LYP/6-311++G (d,p) levels of theory. Result indicates that nitrosamines, nitramines, nitroso-oxy compounds and imines can be formed at atmosphere. Time dependent density functional theory (TDDFT) calculation shows that nitrosamines and nitroso-oxy compounds can photolyze under sunlight, while nitramines cannot undergo photolysis in the daytime. Moreover, the ecotoxicity assessment result implies that the degradation of propyl-substituted amines by OH radicals, NO and NO2 will reduce their toxicity to fish, daphnia and green algae in the aquatic environment.

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The OH-initiated degradation of 2-amino-2-methyl-1-propanol [CH3C(NH2)(CH3)CH2OH, AMP] was investigated in a large atmospheric simulation chamber, employing time-resolved online high-resolution proton-transfer reaction-time-of-flight mass spectrometry (PTR-ToF-MS) and chemical analysis of aerosol online PTR-ToF-MS (CHARON-PTR-ToF-MS) instrumentation, and by theoretical calculations based on M06-2X/aug-cc-pVTZ quantum chemistry results and master equation modeling of the pivotal reaction steps. The quantum chemistry calculations reproduce the experimental rate coefficient of the AMP + OH reaction, aligning k(T) = 5.2 × 10-12 × exp (505/T) cm3 molecule-1 s-1 to the experimental value kexp,300K = 2.8 × 10-11 cm3 molecule-1 s-1. The theoretical calculations predict that the AMP + OH reaction proceeds via hydrogen abstraction from the -CH3 groups (5-10%), -CH2- group, (>70%) and -NH2 group (5-20%), whereas hydrogen abstraction from the -OH group can be disregarded under atmospheric conditions. A detailed mechanism for atmospheric AMP degradation was obtained as part of the theoretical study. The photo-oxidation experiments show 2-amino-2-methylpropanal [CH3C(NH2)(CH3)CHO] as the major gas-phase product and propan-2-imine [(CH3)2C═NH], 2-iminopropanol [(CH3)(CH2OH)C═NH], acetamide [CH3C(O)NH2], formaldehyde (CH2O), and nitramine 2-methyl-2-(nitroamino)-1-propanol [AMPNO2, CH3C(CH3)(NHNO2)CH2OH] as minor primary products; there is no experimental evidence of nitrosamine formation. The branching in the initial H abstraction by OH radicals was derived in analyses of the temporal gas-phase product profiles to be BCH3/BCH2/BNH2 = 6:70:24. Secondary photo-oxidation products and products resulting from particle and surface processing of the primary gas-phase products were also observed and quantified. All the photo-oxidation experiments were accompanied by extensive particle formation that was initiated by the reaction of AMP with nitric acid and that mainly consisted of this salt. Minor amounts of the gas-phase photo-oxidation products, including AMPNO2, were detected in the particles by CHARON-PTR-ToF-MS and GC×GC-NCD. Volatility measurements of laboratory-generated AMP nitrate nanoparticles gave ΔvapH = 80 ± 16 kJ mol-1 and an estimated vapor pressure of (1.3 ± 0.3) × 10-5 Pa at 298 K. The atmospheric chemistry of AMP is evaluated and a validated chemistry model for implementation in dispersion models is presented.