RESUMO
As a promising direct measurement method of atmospheric hydroperoxyl radicals (HO2), bromide chemical ionization mass spectrometry (Br-CIMS) has been first demonstrated by Sanchez et al. (Atmos. Meas. Tech. 2016, 9, 3851-3861). However, field application of this method is currently still sparse, and there is still a gap between measured HO2 concentrations and calculated ones derived from the atmospheric equilibrium between HO2 and peroxynitric acid (HO2NO2). In this work, we constructed an improved Br-CIMS with optimizations of custom-built front-end devices, chamber pressures, and instrumental voltages to achieve a 3σ detection limit of 0.5 ppt at an integration time of 60 s and a sensitivity of 1-3 cps ppt-1 under a total reagent ion signal of 0.2 MHz for HO2 detection. HO2NO2, a product from atmospheric reactions between HO2 and NO2, can also be detected by Br-CIMS, whose interference on the HO2 measurement was found but nearly eliminated by regulating key CIMS voltages to minimize the decomposition of (BrHO2NO2)- ions in the MS. In addition, a 2 week field campaign was carried out in urban Shanghai, demonstrating that the interference of HO2 from ambient HO2NO2 was less than 10% of the true HO2 signal under our optimized CIMS voltage setting. Our study suggests that Br-CIMS is a reliable technique for atmospheric HO2 measurements.
RESUMO
Objective: To investigate the effect of icariin on the transformation efficiency of germ cell-like cells from mouse induced pluripotent stem cells into sperm cells in vitro. Methods: Firstly, mouse induced pluripotent stem cells were induced and cultured to transform into germ cell-like cells, and the primordial germ cell-like cells were identified by Western blot and RT-PCR. Then, different concentrations of icariin (0.1μg/mL, 1μg/mL, 10μg/mL and 100μg/mL) were added into the culture medium, and the obtained primitive germ cell-like cells were cultured, Western blot and RT-PCR were used to identify the obtained sperm cells, the transformation efficiency was compared. Results: The primordium germ cell-like cells obtained from mouse induced pluripotent stem cells in vitro specially expressed Oct-4 protein, C-kit protein, Mvh mRNA, Fragilis mRNA and Stella mRNA. The sperm cells were specially expressed VASA, SCP3 and γH2AX proteins. RT-PCR showed that the sperm cells were specially expressed Ddx4, Tp2 and Prm1 mRNA. Compared with the control group, the expression level of VASA protein (1.744±0.283, 2.882±0.373, 6.489±0.460), SCP3 protein (2.250±0.306, 7.058±0.521, 8.654±0.804), γH2AX protein (4.304±0.433, 5.713±0.339, 9.268±0.545), Ddx4 mRNA (1.374±0.145, 2.846±0.194, 4.021±0.154), Tp2 mRNA (1.358±0.130, 3.623±0.326, 5.811±0.390) and Prm1 mRNA (1.326±0.162, 3.487±0.237, 4.666±0.307) in 0.1μg/mL, 1μg/mL, 10μg/mL icariin experimental groups were all lower than that of VASA protein (10.560±0.413), SCP3 protein (13.804±0.642), γH2AX protein (11.874±0.464), Ddx4 mRNA (6.4005±0.361), Tp2 mRNA (7.314±0.256) and Prm1 mRNA (7.334±0.390) in 100μg/mL icariin experimental group. (AU)
Objetivo: Investigar el efecto de icariina en la eficiencia de la conversión in vitro inducida en espermatozoides de cultivos de células germinativas derivadas de la transformación de células madre pluripotentes inducidas de ratón. Métodos: Primero se indujeron y cultivaron células madre pluripotentes inducidas de ratón para transformarlas en células similares a las células germinales, y las células similares a las células germinales primordiales se identificaron mediante Western blot y RT-PCR. A continuación, se añadieron diferentes concentraciones de icariina (0,1μg/mL, 1μg/mL, 10μg/mL and 100μg/mL) al medio de cultivo, y se cultivaron las células primitivas similares a células germinales obtenidas, se utilizaron Western blot y RT-PCR para identificar las células espermáticas obtenidas, y se comparó la eficacia de la transformación. Resultados: Las células germinales primitivas obtenidas in vitro a partir de células madre pluripotentes inducidas de ratón expresaron especialmente la proteína Oct-4, la proteína C-kit, el ARNm de Mvh, el ARNm de Fragilis y el ARNm de Stella. Los espermatozoides expresaban especialmente las proteínas VASA, SCP3 y γH2AX. La RT-PCR mostró que los espermatozoides expresaban especialmente los ARNm Ddx4, Tp2 y Prm1. En comparación con el grupo de control, el nivel de expresión de la proteína VASA (1,744±0,283; 2,882±0,373; 6,489±0,460), la proteína SCP3 (2,250±0,306; 7,058± 0,521; 8,654±0,804), proteína γH2AX (4,304±0,433; 5,713±0,339; 9,268±0,545), ARNm Ddx4 (1,374±0,145; 2,846±0,194; 4,021±0,154), ARNm Tp2 (1,358±0,130; 3,623±0,326; 5,811±0,390) y ARNm Prm1 (1,326±0,162; 3,487±0,237; 4,666±0,307) en grupos experimentales de 0,1μg/mL, 1μg/mL, 10μg/mL de icariina fueron todos más bajos que los de la proteína VASA (10,560±0,413), proteína SCP3 (13,804±0,642), proteína γH2AX (11,874±0,464), ARNm Ddx4 (6,4005±0,361), ARNm Tp2 (7,314±0,256) y ARNm Prm1 (7,334±0,390) en 100μg/mL icariina grupo experimental. (AU)
Assuntos
Animais , Camundongos , Epimedium , Células-Tronco Pluripotentes Induzidas , Infertilidade , Flavonoides/farmacologia , Flavonoides/efeitos adversos , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/efeitos adversos , Sêmen , AzoospermiaRESUMO
BACKGROUND: Testicular volume in neonates is a potential indicator of testicular development during the fetal period, particularly the masculinization programming window. Reliable measurements of testicular volume provide an opportunity for early detection of testicular abnormalities. This study aimed to assess the testicular volume in neonates and evaluate its relationship with gestational week and birth weight in Hainan Province, China. METHODS: Data on 458 neonates who underwent ultrasonography examinations at our institution from 2018 to 2022 were collected. The neonates were categorized by gestational week, birth weight, and presence of cryptorchidism. We evaluated the testicular volume among different groups and its relationship to gestational week and birth weight. RESULTS: There was no significant difference between the right and left testicular volume in neonates without cryptorchidism. However, a significant difference was observed between normal birth weight and low birth weight neonates in terms of testicular volume. Similarly, there was a significant difference between premature and full-term neonates in testicular volume. Bilateral testicular volume showed positive and significant correlations with gestational week and birth weight. Additionally, a significant difference was noted in testicular volume between the affected side in neonates with cryptorchidism and the same side in normal birth weight full-term neonates. CONCLUSIONS: We established the normal range of testicular volume for neonates in Hainan Province and demonstrated that testicular volume is positively correlated with both birth weight and gestational week. Cryptorchidism also affects testicular volume during the neonatal period, likely due to reduced androgenic exposure in utero, particularly during the masculinization programming window. The findings of this study have significant implications for assessing testis development during fetal development.
Assuntos
Criptorquidismo , Masculino , Recém-Nascido , Humanos , Peso ao Nascer , Criptorquidismo/diagnóstico por imagem , China , Desenvolvimento Fetal , Instalações de SaúdeRESUMO
OBJECTIVE: To investigate the effect of icariin on the transformation efficiency of germ cell-like cells from mouse induced pluripotent stem cells into sperm cells in vitro. METHODS: Firstly, mouse induced pluripotent stem cells were induced and cultured to transform into germ cell-like cells, and the primordial germ cell-like cells were identified by Western blot and RT-PCR. Then, different concentrations of icariin (0.1µg/mL, 1µg/mL, 10µg/mL and 100µg/mL) were added into the culture medium, and the obtained primitive germ cell-like cells were cultured, Western blot and RT-PCR were used to identify the obtained sperm cells, the transformation efficiency was compared. RESULTS: The primordium germ cell-like cells obtained from mouse induced pluripotent stem cells in vitro specially expressed Oct-4 protein, C-kit protein, Mvh mRNA, Fragilis mRNA and Stella mRNA. The sperm cells were specially expressed VASA, SCP3 and γH2AX proteins. RT-PCR showed that the sperm cells were specially expressed Ddx4, Tp2 and Prm1 mRNA. Compared with the control group, the expression level of VASA protein (1.744±0.283, 2.882±0.373, 6.489±0.460), SCP3 protein (2.250±0.306, 7.058±0.521, 8.654±0.804), γH2AX protein (4.304±0.433, 5.713±0.339, 9.268±0.545), Ddx4 mRNA (1.374±0.145, 2.846±0.194, 4.021±0.154), Tp2 mRNA (1.358±0.130, 3.623±0.326, 5.811±0.390) and Prm1 mRNA (1.326±0.162, 3.487±0.237, 4.666±0.307) in 0.1µg/mL, 1µg/mL, 10µg/mL icariin experimental groups were all lower than that of VASA protein (10.560±0.413), SCP3 protein (13.804±0.642), γH2AX protein (11.874±0.464), Ddx4 mRNA (6.4005±0.361), Tp2 mRNA (7.314±0.256) and Prm1 mRNA (7.334±0.390) in 100µg/mL icariin experimental group. CONCLUSIONS: Icariin can promote the transformation of mouse induced pluripotent stem cells into sperm cells in vitro, and it is concentration-dependent manner in a certain concentration range.
Assuntos
Células-Tronco Pluripotentes Induzidas , Masculino , Animais , Camundongos , Células-Tronco Pluripotentes Induzidas/metabolismo , Diferenciação Celular , Sêmen , Espermatozoides , RNA Mensageiro/metabolismoRESUMO
Gas-phase dimethylamine (DMA) has recently been identified as one of the most important vapors to initiate new particle formation (NPF), even in China's polluted atmosphere. Nevertheless, there remains a fundamental need for understanding the atmospheric life cycle of DMA, particularly in urban areas. Here we pioneered large-scale mobile observations of the DMA concentrations within cities and across two pan-region transects of north-to-south (â¼700 km) and west-to-east (â¼2000 km) in China. Unexpectedly, DMA concentrations (mean ± 1σ) in South China with scattered croplands (0.018 ± 0.010 ppbv, 1 ppbv=10-9 L/L) were over three times higher than those in the north with contiguous croplands (0.005 ± 0.001 ppbv), suggesting that nonagricultural activities may be an important source of DMA. Particularly in non-rural regions, incidental pulsed industrial emissions led to some of the highest DMA concentration levels in the world (>2.3 ppbv). Besides, in highly urbanized areas of Shanghai, supported by direct source-emission measurements, the spatial pattern of DMA was generally correlated with population (R2 = 0.31) due to associated residential emissions rather than vehicular emissions. Chemical transport simulations further show that in the most populated regions of Shanghai, residential DMA emissions can contribute for up to 78% of particle number concentrations. Shanghai is a case study for populous megacities, and the impacts of nonagricultural emissions on local DMA concentration and nucleation are likely similar for other major urban regions globally.
RESUMO
Monocyclic aromatic hydrocarbons (MAHs) and polycyclic aromatic hydrocarbons (PAHs) are both well known as hazardous air pollutants and also important anthropogenic precursors of tropospheric ozone (O3) and secondary organic aerosols (SOA). In recent years, there have been intensive studies covering MAHs emission from various sources and their behavior under stimulated photochemical conditions. Yet in-situ measurements of PAHs presence and variations in ambient air are sparse. Herein we conducted large geometrical scale mobile measurements for 16 aromatic hydrocarbons (AHs, including 7 MAHs and 9 PAHs) in eastern China between October 27 and November 8, 2019. This unique dataset has allowed for some insights in terms of AHs concentration variations, accompanying chemical composition, source contributions and spatial distributions in eastern China. In general, AHs showed a clear concentration variability between the south and the north of the Yangtze River Delta (YRD). The concentrations of PAHs were approximately 9% of AHs, but contributed 23% of SOA formation potential. Source apportionment via positive matrix factorization (PMF) model revealed that industrial processes as the largest source (44%) of observed AHs, followed by solvent usage (21%), vehicle exhaust (19%), coal combustion (11%) and coking processes (6%). In the perspective of PAHs sources, coal combustion emissions were identified as the dominating factor of a share of 41%-52% in eastern China. Our findings complemented the simultaneously monitoring information of PAHs and MAHs in eastern China, revealed the importance of PAHs to SOA formation and highlighted the necessity of formulating strategies to reduce emissions from anthropogenic sources and reduce risks to human health.
Assuntos
Poluentes Atmosféricos , Ozônio , Hidrocarbonetos Policíclicos Aromáticos , Humanos , Monitoramento Ambiental , Poluentes Atmosféricos/análise , Emissões de Veículos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , China , Carvão Mineral/análiseRESUMO
Objective: Ankle dorsiflexion during walking causes the tibia to roll forward relative to the foot to achieve body forward. Individuals with ankle dorsiflexion restriction may present altered movement patterns and cause a series of dysfunction. Therefore, the aim of this research was to clearly determine the effects of peak ankle dorsiflexion angle on lower extremity biomechanics and pelvic motion during walking and jogging. Method: This study involved 51 subjects tested for both walking and jogging. The motion capture system and force measuring platforms were used to synchronously collect kinematics and kinetics parameters during these activities. Based on the peak ankle dorsiflexion angle during walking, the 51 subjects were divided into a restricted group (RADF group, angle <10°) and an ankle dorsiflexion-unrestricted group (un-RADF group, angle >10°). Independent-Sample T-tests were performed to compare the pelvic and lower limb biomechanics parameters between the groups during walking and jogging test on this cross-sectional study. Results: The parameters that were significantly smaller in the RADF group than in the un-RADF group at the moment of peak ankle dorsiflexion in the walking test were: ankle plantar flexion moment (p < 0.05), hip extension angle (p < 0.05), internal ground reaction force (p < 0.05), anterior ground reaction force (p < 0.01), pelvic ipsilateral tilt angle (p < 0.05). In contrast, the external knee rotation angle was significantly greater in the RADF group than in the un-RADF group (p < 0.05). The parameters that were significantly smaller in the RADF group than in the un-RADF group at the moment of peak ankle dorsiflexion in the jogging test were: peak ankle dorsiflexion angle (p < 0.01); the anterior ground reaction force (p < 0.01), the angle of pelvic ipsilateral rotation (p < 0.05). Conclusion: This study shows that individuals with limited ankle dorsiflexion experience varying degrees of altered kinematics and dynamics in the pelvis, hip, knee, and foot during walking and jogging. Limited ankle dorsiflexion alters the movement pattern of the lower extremity during walking and jogging, diminishing the body's ability to propel forward, which may lead to higher injury risks.
RESUMO
During the Covid-19 outbreak, strict lockdown measures led to notable reductions in transportation-related emissions and significantly altered atmospheric pollution characteristics in urban and suburban areas. In this work, we compare comprehensive online measurements of PM2.5 major components and organic molecular markers in a suburban location in Shanghai, China before lockdown (Dec. 28, 2019 to Jan. 23, 2020) and during lockdown (Jan. 24 to Feb. 9, 2020). The NOx levels declined sharply by 59% from 44 to 18 ppb during the lockdown, while O3 rose two times higher to 42 ppb. The PM2.5 level dropped from 64 to 49 µg m-3 (-24%). The major components all showed reductions, with the reduction of nitrate most prominent at -58%, followed by organics at -19%, and sulfate at -17%. Positive matrix factorization analysis identifies fourteen source factors, including nine primary sources and five secondary sources. The secondary sources consist of sulfate-rich factor, nitrate-rich factor, and three secondary organic aerosol (SOA) factors, with SOA_I being anthropogenic SOA, SOA_II associated with later generation products of organic oxidation, and SOA_III being biogenic SOA. The combined secondary sources contributed to 69% and 63% (40 and 22 µg m-3) of PM2.5 before and during lockdown, respectively, among which the reductions in the nitrate-rich (-55%) factor was the most prominent. Among primary sources, large reductions (>80%) were observed in contributions from industrial, cooking, and vehicle emissions. Unlike some studies reporting that the restriction during the Covid-19 resulted in enhanced secondary sulfate and SOA formation, we observed decreases in both secondary inorganic and SOA formation despite the overall elevated oxidizing capacity in the suburban site. Our results indicate that the formation change in secondary inorganic and organic compounds in response to substantial reductions in urban primary precursors are different for urban and suburban environments.
RESUMO
Secondary organic aerosol, formed through atmospheric oxidation processes, plays an important role in affecting climate and human health. In this study, we conducted a comprehensive campaign in the megacity of Shanghai during the 2019 International Import Expo (EXPO), with the first deployment of a chemical ionizationâOrbitrap mass spectrometer for ambient measurements. With the ultrahigh mass resolving power of the Orbitrap mass analyzer (up to 140,000 Th/Th) and capability in dealing with massive spectral data sets by positive matrix factorization, we were able to identify the major gas-phase oxidation processes leading to the formation of oxygenated organic molecules (OOM) in Shanghai. Nine main factors from three independent sub-range analysis were identified. More than 90% of OOM are of anthropogenic origin and >60% are nitrogen-containing molecules, mainly dominated by the RO2 + NO and/or NO3 chemistry. The emission control during the EXPO showed that even though the restriction was effectual in significantly lowering the primary pollutants (20-70% decrease), the secondary oxidation products responded less effectively (14% decrease), or even increased (50 to >200%) due to the enhancement of ozone and the lowered condensation sink, indicating the importance of a stricter multi-pollutant coordinated strategy in primary and secondary pollution mitigation.
Assuntos
Poluentes Atmosféricos , Ozônio , Aerossóis/química , Poluentes Atmosféricos/análise , China , Humanos , Ozônio/análise , Material Particulado/análiseRESUMO
Background: Metanephric adenoma is an extremely rare renal neoplasm, especially in pediatrics. Chemotherapy combined with surgery in metanephric adenoma has not been reported. Methods: We describe a case of metanephric adenoma in a child less than 2 years old, which were treated by chemotherapy combined with surgery. Results: Nephron sparing surgery was performed after regular chemotherapy, and the pathological result was metanephric adenoma. Conclusion: Pediatric metanephric adenoma is extremely rare; the clinical manifestations and imaging examinations lack specificity. Nephron sparing surgery is recommended as the preferred treatment for metanephric adenoma. Long-term follow-up and more in-depth molecular genetic research are still needed to determine the benign or malignant of metanephric adenoma and whether chemotherapy drugs have an effect on it.
RESUMO
OBJECTIVE: To assess the testicular volume in children with unilateral cryptorchidism of different ages in Hainan Province, China. METHODS: The study included 424 children (ranging in age from 0 month to 4 years) with unilateral cryptorchidism or normal who were treated from 2017 to 2021 at our institution. They were divided into different groups according to age. We evaluated the correlation of testicular volume between the children with cryptorchidism and the normal children among different groups. RESULTS: There was a significant difference in testicular volume between the affected side and the healthy side. There was no difference in testicular volume between the left side and the right side of each control group. There were significant differences between the affected side of cryptorchid groups and the same side of the control groups. There were no significant differences between the healthy side of cryptorchid groups and the same side of the control groups. There were no significant differences between the affected side of left cryptorchid groups and right cryptorchid groups. There were no significant differences between the healthy side of left cryptorchid groups and right cryptorchid groups. There were significant differences in testicular volume among different age groups of the control group, while there were no differences in the cryptorchid groups. CONCLUSIONS: The development of testicular volume in children with unilateral inguinal cryptorchidism is affected in earlier age, and there was no compensatory testicular adaptation in the healthy testis.
Assuntos
Criptorquidismo , Criança , China/epidemiologia , Humanos , Masculino , TestículoRESUMO
Organic acids are important contributors to the acidity of atmospheric precipitation, but their existence in the Chinese atmosphere is largely unclear. In this study, twelve atmospheric gaseous organic acids, including C1-C9 alkanoic acids, methacrylic acid, pyruvic acid, and benzoic acid, were observed in the suburb of Wangdu, Hebei Province, a typical rural site in the northern China plain from 16th December, 2018 to 22nd January, 2019, using a Vocus® Proton-Transfer-Reaction time-of-flight mass spectrometer (Vocus PTR-ToF). The quantification of C2-C4 alkanoic acids by the Vocus PTR-ToF was calibrated according to the titration of a NaOH solution by C2-C4 alkanoic acids from home-made permeation sources, and the other organic acids except for formic acid were quantified based on the kcap-sensitivity linearity in the Vocus PTR-ToF, whereas formic acid was not quantified because our instrument setting led to a significant underestimation in its concentration. The average total concentration of eleven gaseous organic acids was 6.96 ± 5.20 ppbv (parts per billion by volume). The average concentration of acetic acid was the highest (3.86 ± 3.00 ppbv), followed by propanoic acid, butyric acid, and methacrylic acid. Domestic straw burning was likely the dominant source of the observed gaseous organic acids according to the good correlations between acetonitrile and organic acids and between particulate K+ and organic acids, and traffic emissions could also have contributed. During episodes with continuously high concentrations of organic acids, short-distance transport dominated in Wangdu according to the backward trajectory analysis. Baoding, Shijiazhuang, and Hengshui areas were the main source areas based on potential source contribution function and concentration weighing track analysis.
Assuntos
Poluentes Atmosféricos , Gases , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Compostos Orgânicos/análiseRESUMO
The understanding at a molecular level of ambient secondary organic aerosol (SOA) formation is hampered by poorly constrained formation mechanisms and insufficient analytical methods. Especially in developing countries, SOA related haze is a great concern due to its significant effects on climate and human health. We present simultaneous measurements of gas-phase volatile organic compounds (VOCs), oxygenated organic molecules (OOMs), and particle-phase SOA in Beijing. We show that condensation of the measured OOMs explains 26-39% of the organic aerosol mass growth, with the contribution of OOMs to SOA enhanced during severe haze episodes. Our novel results provide a quantitative molecular connection from anthropogenic emissions to condensable organic oxidation product vapors, their concentration in particle-phase SOA, and ultimately to haze formation.
Assuntos
Poluentes Atmosféricos , Compostos Orgânicos Voláteis , Aerossóis/análise , Poluentes Atmosféricos/análise , Pequim , HumanosRESUMO
Molecular clustering is the initial step of atmospheric new particle formation (NPF) that generates numerous secondary particles. Using two online mass spectrometers with and without a chemical ionization inlet, we characterized the neutral clusters and the naturally charged ion clusters during NPF periods in urban Beijing. In ion clusters, we observed pure sulfuric acid (SA) clusters, SA-amine clusters, SA-ammonia (NH3) clusters, and SA-amine-NH3 clusters. However, only SA clusters and SA-amine clusters were observed in the neutral form. Meanwhile, oxygenated organic molecule (OOM) clusters charged by a nitrate ion and a bisulfate ion were observed in ion clusters. Acid-base clusters correlate well with the occurrence of sub-3 nm particles, whereas OOM clusters do not. Moreover, with the increasing cluster size, amine fractions in ion acid-base clusters decrease, while NH3 fractions increase. This variation results from the reduced stability differences between SA-amine clusters and SA-NH3 clusters, which is supported by both quantum chemistry calculations and chamber experiments. The lower average number of dimethylamine (DMA) molecules in atmospheric ion clusters than the saturated value from controlled SA-DMA nucleation experiments suggests that there is insufficient DMA in urban Beijing to fully stabilize large SA clusters, and therefore, other basic molecules such as NH3 play an important role.
RESUMO
BACKGROUND: Code Blue is a popular hospital emergency code that is used to alert the emergency response team to any medical emergency requiring critical care. By retrospectively studying Code Blue cases in a children's hospital, we looked for high-risk factors associated with survival and how to improve the effectiveness of Code Blue systems through training. METHODS: Data were collected on age, gender, department, diagnosis, time of Code Blue call activation, time between call and arrival of the Code Blue team, treatment details and outcome before and after the training process from January 2016 to December 2019. Chi-square test and logistic regression analysis were used to analyze the data. RESULTS: A total of 139 Code Blue cases from the period of January 2016 to December 2019 were retrospectively studied. The wards where Code Blues occurred most frequently were the infectious diseases ward (n=31, 22.3%), the hematology and oncology ward (n=30, 21.6%), and the cardiology ward (n=15, 10.8%). Age, inpatient status, time of arrival, the time of cardiopulmonary resuscitation (CPR), and the cause of shock were all risk factors for death. After the training, the arrival time and recovery time were significantly reduced (P<0.01). The proportion of patients who were transferred to the ICU had increased (P<0.05), and the proportion of deaths had decreased (P<0.01). The survival curve improved (P<0.05). CONCLUSIONS: It is very important to summarize the risk factors related to Code Blue. It is clear that the efficacy of the Code Blue events improved after training of the hospital staff in the Children's Hospital.
RESUMO
Atmospheric gas-to-particle conversion is a crucial or even dominant contributor to haze formation in Chinese megacities in terms of aerosol number, surface area and mass. Based on our comprehensive observations in Beijing during 15 January 2018-31 March 2019, we are able to show that 80-90% of the aerosol mass (PM2.5) was formed via atmospheric reactions during the haze days and over 65% of the number concentration of haze particles resulted from new particle formation (NPF). Furthermore, the haze formation was faster when the subsequent growth of newly formed particles was enhanced. Our findings suggest that in practice almost all present-day haze episodes originate from NPF, mainly since the direct emission of primary particles in Beijing has considerably decreased during recent years. We also show that reducing the subsequent growth rate of freshly formed particles by a factor of 3-5 would delay the buildup of haze episodes by 1-3 days. Actually, this delay would decrease the length of each haze episode, so that the number of annual haze days could be approximately halved. Such improvement in air quality can be achieved with targeted reduction of gas-phase precursors for NPF, mainly dimethyl amine and ammonia, and further reductions of SO2 emissions. Furthermore, reduction of anthropogenic organic and inorganic precursor emissions would slow down the growth rate of newly-formed particles and consequently reduce the haze formation.
RESUMO
Understanding the atmospheric new particle formation (NPF) process within the global range is important for revealing the budget of atmospheric aerosols and their impacts. We investigated the seasonal characteristics of NPF in the urban environment of Beijing. Aerosol size distributions down to â¼1 nm and H2SO4 concentration were measured during 2018-2019. The observed formation rate of 1.5 nm particles (J1.5) is significantly higher than those in the clean environment, e.g., Hyytiälä, whereas the growth rate is not significantly different. Both J1.5 and NPF frequency in urban Beijing show a clear seasonal variation with maxima in winter and minima in summer, while the observed growth rates are generally within the same range around the year. We show that ambient temperature is a governing factor driving the seasonal variation of J1.5. In contrast, the condensation sink and the daily maximum H2SO4 concentration show no significant seasonal variation during the NPF periods. In all four seasons, condensation of H2SO4 and (H2SO4)n(amine)n clusters contributes significantly to the growth rates in the sub-3 nm size range, whereas it is less important for the observed growth rates of particles above 3 nm. Therefore, other species are always needed for the growth of larger particles.
Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Pequim , Monitoramento Ambiental , Tamanho da Partícula , Material Particulado/análise , Estações do AnoRESUMO
Atmospheric new particle formation (NPF) is an important global phenomenon that is nevertheless sensitive to ambient conditions. According to both observation and theoretical arguments, NPF usually requires a relatively high sulfuric acid (H2SO4) concentration to promote the formation of new particles and a low preexisting aerosol loading to minimize the sink of new particles. We investigated NPF in Shanghai and were able to observe both precursor vapors (H2SO4) and initial clusters at a molecular level in a megacity. High NPF rates were observed to coincide with several familiar markers suggestive of H2SO4-dimethylamine (DMA)-water (H2O) nucleation, including sulfuric acid dimers and H2SO4-DMA clusters. In a cluster kinetics simulation, the observed concentration of sulfuric acid was high enough to explain the particle growth to ~3 nanometers under the very high condensation sink, whereas the subsequent higher growth rate beyond this size is believed to result from the added contribution of condensing organic species. These findings will help in understanding urban NPF and its air quality and climate effects, as well as in formulating policies to mitigate secondary particle formation in China.
RESUMO
The evaluation of a meteorological disaster can be regarded as a multiple-criteria decision making problem because it involves many indexes. Firstly, a comprehensive indexing system for an agricultural meteorological disaster is proposed, which includes the disaster rate, the inundated rate, and the complete loss rate. Following this, the relative weights of the three criteria are acquired using a novel proposed evolutionary algorithm. The proposed algorithm consists of a differential evolution algorithm and an evolution strategy. Finally, a novel evaluation model, based on the proposed algorithm and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), is presented to estimate the agricultural meteorological disaster of 2008 in China. The geographic information system (GIS) technique is employed to depict the disaster. The experimental results demonstrated that the agricultural meteorological disaster of 2008 was very serious, especially in Hunan and Hubei provinces. Some useful suggestions are provided to relieve agriculture meteorological disasters.
Assuntos
Agricultura , Algoritmos , Técnicas de Apoio para a Decisão , Desastres , Modelos Teóricos , Tempo (Meteorologia) , China , Sistemas de Informação GeográficaRESUMO
A hierarchical titanosilicate, with epitaxially grown MFI nanosheets on microsized TS-1 crystals, has been prepared through a desilication-recrystallization method using a diammonium surfactant as the secondary structure-directing agent (SDA). This core/shell material features multiple mesoporosities, significantly improved epoxidation activity as well as easy separation in synthesis and catalytic reactions.