A molecular perspective for global modeling of upper atmospheric NH3 from freezing clouds.

Ammonia plays a key role in the neutralization of atmospheric acids such as sulfate and nitrates. A few in situ observations have supported the theory that gas-phase NH3 concentrations should decrease sharply with altitude and be extremely low in the upper troposphere and lower stratosphere (UTLS). This theory, however, seems inconsistent with recent satellite measurements and is also not supported by the aircraft data showing highly or fully neutralized sulfate aerosol particles by ammonium in the UTLS in many parts of the world. Here we reveal the contributions of deep convective clouds to NH3 in the UTLS by using integrated cross-scale modeling, which includes molecular dynamic simulations, a global chemistry transport model, and satellite and aircraft measurements. We show that the NH3 dissolved in liquid cloud droplets is prone to being released into the UTLS upon freezing during deep convection. Because NH3 emission is not regulated in most countries and its future increase is likely persistent from agricultural growth and the warmer climate, the effect of NH3 on composition and phase of aerosol particles in the UTLS can be significant, which in turn can affect cirrus cloud formation, radiation, and the budgets of NOx and O3.

[Effects of maternal exposure to nano-alumina during pregnancy on neurodevelopment in offspring mice].

OBJECTIVE: To observe the effects of maternal exposure to nano-alumina during pregnancy on the neurodevelopment in offspring mice. METHODS: Female ICR mice began to be exposed to nano-alumina 10 d before mating, and the nano-alumina exposure lasted till offspring mice were born. All the female mice were randomly divided into 5 groups: solvent control group (saline), nano-carbon group (11.76 mg/ml), micro-alumina group (50 mg/ml), 50 nm alumina group (50 mg/ml), and 13 nm alumina group (50 mg/ml). All the mice were treated by nasal drip (10 µl/time) 3 times daily till offspring mice were born. Physiological indices, reflex and sensory function test, endurance test, Morris water maze test, positioning and navigation test, and open field test were used to evaluate the neurodevelopment of newborn mice. RESULTS: On day 28, the body weight of 13 nm alumina group (16.73±4.04 g) was significantly lower than that of solvent control group (20.45±2.50 g) (P<0.01); the 13 nm alumina group had significantly delayed time to ear opening compared with the solvent control group (4.91±0.78 d vs 4.45±0.50 d, P<0.01); compared with the solvent control group, the nano-carbon group, micro-alumina group, 50 nm alumina group, and 13 nm alumina group had significantly delayed time to eruption of teeth (10.05±0.23 d vs 10.32±0.48 d, 10.75±0.45 d, 10.32±0.47 d, and 10.79±0.49 d, P<0.05 or P<0.01). On days 4 and 7 after birth, compared with the solvent control group, other groups had significantly decreased proportions of mice which passed the cliff avoidance test (P < 0.05 or P < 0.01). On days 12 and 14 after birth, compared with the solvent control group, the nano-carbon group, 50 nm alumina group, and 13 nm alumina group had significantly reduced pre-suspension time in the endurance test (P < 0.05 or P < 0.01). The Morris water maze and positioning and navigation tests showed that the 13 nm alumina group had a significantly increased 5 d incubation period compared with the solvent control group (P < 0.05); compared with the solvent control group, other groups had significantly reduced numbers of platform crossings (P < 0.05 or P < 0.01). The open field test showed that the nano-carbon group and 13 nm alumina group had reduced numbers of rearings compared with the solvent control group (P < 0.05); compared with the solvent control group, other groups had significantly reduced numbers of modifications (P < 0.01). CONCLUSION: Maternal exposure to nano-alumina (13 nm) during pregnancy has inhibitory effects on the physical development and early behavioral development in newborn mice and can also inhibit the learning and memory abilities and adaptability to new environment in offspring mice. The neurodevelopmental toxicity of nano-alumina to newborn mice increases as the particle sizes of nano-alumina decrease, which has been demonstrated by the endurance test and number of rearings.

Resolving and Predicting Neighborhood Vulnerability to Urban Heat and Air Pollution: Insights From a Pilot Project of Community Science.

Urban heat and air pollution, two environmental threats to urban residents, are studied via a community science project in Los Angeles, CA, USA. The data collected, for the first time, by community members, reveal the significance of both the large spatiotemporal variations of and the covariations between 2 m air temperature (2mT) and ozone (O3) concentration within the (4 km) neighborhood scale. This neighborhood variation was not exhibited in either daily satellite observations or operational model predictions, which makes the assessment of community health risks a challenge. Overall, the 2mT is much better predicted than O3 by the weather and research forecast model with atmospheric chemistry (WRF-Chem). For O3, diurnal variation is better predicted by WRF-Chem than spatial variation (i.e., underestimated by 50%). However, both WRF-chem and the surface observation show the overall consistency in describing statistically significant covariations between O3 and 2mT. In contrast, satellite-based land surface temperature at 1 km resolution is insufficient to capture air temperature variations at the neighborhood scale. Community engagement is augmented with interactive maps and apps that show the predictions in near real time and reveals the potential of green canopy to reduce air temperature and ozone; but different tree types and sizes may lead to different impacts on air temperature, which is not resolved by the WRF-Chem. These findings highlight the need for community science engagement to reveal otherwise impossible insights for models, observations, and real-time dissemination to understand, predict, and ultimately mitigate, urban neighborhood vulnerability to heat and air pollution.

Improving surface PM2.5 forecasts in the United States using an ensemble of chemical transport model outputs: 2. bias correction with satellite data for rural areas.

This work serves as the second of a two-part study to improve surface PM2.5 forecasts in the continental U.S. through the integrated use of multi-satellite aerosol optical depth (AOD) products (MODIS Terra/Aqua and VIIRS DT/DB), multi chemical transport model (CTM) (GEOS-Chem, WRF-Chem and CMAQ) outputs and ground observations. In part I of the study, a multi-model ensemble Kalman filter (KF) technique using three CTM outputs and ground observations was developed to correct forecast bias and generate a single best forecast of PM2.5 for next day over non-rural areas that have surface PM2.5 measurements in the proximity of 125 km. Here, with AOD data, we extended the bias correction into rural areas where the closest air quality monitoring station is at least 125 - 300 km away. First, we ensembled all of satellite AOD products to yield the single best AOD. Second, we corrected daily PM2.5 in rural areas from multiple models through the AOD spatial pattern between these areas and non-rural areas, referred to as "extended ground truth" or EGT, for today. Lastly, we applied the KF technique to update the bias in the forecast for next day using the EGT. Our results find that the ensemble of bias-corrected daily PM2.5 from three models for both today and next day show the best performance. Together, the two-part study develops a multi-model and multi-AOD bias correction technique that has the potential to improve PM2.5 forecasts in both rural and non-rural areas in near real time, and be readily implemented at state levels.

Depressive symptoms and occupational stress among Chinese female nurses: the mediating effects of social support and rational coping.

The study reported here was designed to investigate the relationship between depressive symptoms and occupational stress in female nurses in China during the period June-July 2008. The hypothesis tested was that social support and rational coping would mediate the effects of occupational stress on depressive symptoms. Our structural equation modeling revealed that social support and rational coping were negatively correlated with depressive symptoms. Social support and rational coping mediated the effects of occupational stress on depressive symptoms. Role overload, role insufficiency, and role boundary were predictive of depressive symptoms. These results indicated that lessening occupational stress and strengthening social support and rational coping could decrease depressive symptoms among Chinese female nurses.

Simulated seasonal variations in wet acid depositions over East Asia.

The air quality modeling system Regional Atmospheric Modeling System-Community Multi-scale Air Quality (RAMS-CMAQ) was applied to analyze temporospatial variations in wet acid deposition over East Asia in 2005, and model results obtained on a monthly basis were evaluated against extensive observations, including precipitation amounts at 704 stations and SO4(2-), NO3-, and NH4+ concentrations in the atmosphere and rainwater at 18 EANET (the Acid Deposition Monitoring Network in East Asia) stations. The comparison shows that the modeling system can reasonably reproduce seasonal precipitation patterns, especially the extensive area of dry conditions in northeast China and north China and the major precipitation zones. For ambient concentrations and wet depositions, the simulated results are in reasonable agreement (within a factor of 2) with observations in most cases, and the major observed features are mostly well reproduced. The analysis of modeled wet deposition distributions indicates that East Asia experiences noticeable variations in its wet deposition patterns throughout the year. In winter, southern China and the coastal areas of the Japan Sea report higher S04(2-) and NO3- wet depositions. In spring, elevated SO4(2-) and NO3-wet depositions are found in northeastern China, southern China, and around the Yangtze River. In summer, a remarkable rise in precipitation in northeastern China, the valleys of the Huaihe and Yangtze rivers, Korea, and Japan leads to a noticeable increase in SO4(2-) and NO3- wet depositions, whereas in autumn, higher SO4(2-) and NO3-wet depositions are found around Sichuan Province. Meanwhile, due to the high emission of SO2, high wet depositions of SO4(2-) are found throughout the entire year in the area surrounding Sichuan Province. There is a tendency toward decreasing NO3- concentrations in rainwater from China through Korea to Japan in both observed and simulated results, which is a consequence of the influence of the continental outflow from Eurasia. The same tendency is not found for SO4(2-).

[Changes of brain oxidative stress induced by nano-alumina in ICR mice].

OBJECTIVE: To investigate the brain oxidative stress injury induced by nano-alumina particles in ICR mice. METHODS: Sixty male ICR mice were randomly divided into 6 groups: control group, solvent control group, 100 mg/kg micro-alumina particles group, 3 groups exposed to nano-alumina particles at the doses of 50, 100 and 200 mg/kg. The mice were exposed by nasal drip for 30 days. Then levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) in brain tissues of mice were detected. RESULTS: There was no difference of SOD activity in mouse brain between control group [(17.32 +/- 6.23)U/gHb] and 50 mg/kg nano-alumina particles group [(17.89 +/- 1.82) U/gHb]. The SOD activity [(4.93 +/- 2.30)U/gHb] in 200 mg/kg nano-alumina particles group was significantly lower than that in control group (P < 0.05). The MDA levels in 3 nano-alumina particles groups were (0.76 +/- 0.13), (1.00 +/- 0.30) and (1.16 +/- 0.39)nmol/ml, respectively, which were significantly higher than that [( 0.24 +/- 0.09)nmol/ml] in control group (P < 0.05). The GSH levels in 3 nano-alumina particles groups were (0.72 +/- 0.08), (0.55 +/- 0.19) and (0.61 +/- 0.20)mg/gpro, respectively, which were significantly lower than that [(1.55 +/- 0.34)mg/gpro]] in control group (P < 0.05). The CAT activity in 50 and 100 mg/kg nano-alumina particles groups were (10.40 +/- 3.84) and (10.40 +/- 2.00)U/mgpro, respectively, which were significantly higher than that [(5.79 +/- 0.96) U/mgpro] in control group (P < 0.05). The CAT activity [(3.25 +/- 1.04)U/mgpro] in 200 mg/kg nano-alumina particles group was significantly lower than that in control group (P < 0.05 ). CONCLUSION: Nano-alumina particles can induce the oxidative stress damage in brain tissues of mice.

Tubgcp3 is a mitotic regulator of planarian epidermal differentiation.

Tubgcp3/GCP3 (The centrosomal protein γ-tubulin complex protein 3) is a component of the γ-tubulin small complexes (γ-TuSCs) and γ-tubulin ring complexes (γ-TuRCs), which play critical roles in mitotic spindle formation during mitosis. However, its function in stem cell development has not been thoroughly elucidated. The planarian flatworm, which contains a large number of adult somatic stem cells (neoblasts), is a unique model to study stem cell lineage development in vivo. Here, we identified a homolog of Tubgcp3 in planarian Dugesia japonica, and found that Tubgcp3 is required for the maintenance of epidermal lineage. RNAi targeting Tubgcp3 resulted in tissue homeostasis and regeneration defect. Knockdown of Tubgcp3 reduced cell divisions and led to a loss of the mature epidermal cells. Our findings indicate that Tubgcp3 is a mitotic regulator and plays a crucial role in planarian epidermal differentiation.

Improving Surface PM2.5 Forecasts in the United States Using an Ensemble of Chemical Transport Model Outputs: 1. Bias Correction With Surface Observations in Nonrural Areas.

This work is the first of a two-part study that aims to develop a computationally efficient bias correction framework to improve surface PM2.5 forecasts in the United States. Here, an ensemble-based Kalman filter (KF) technique is developed primarily for nonrural areas with approximately 500 surface observation sites for PM2.5 and applied to three (GEOS-Chem, WRF-Chem, and WRF-CMAQ) chemical transport model (CTM) hindcast outputs for June 2012. While all CTMs underestimate daily surface PM2.5 mass concentration by 20-50%, KF correction is effective for improving each CTM forecast. Subsequently, two ensemble methods are formulated: (1) the arithmetic mean ensemble (AME) that equally weights each model and (2) the optimized ensemble (OPE) that calculates the individual model weights by minimizing the least-square errors. While the OPE shows superior performance than the AME, the combination of either the AME or the OPE with a KF performs better than the OPE alone, indicating the effectiveness of the KF technique. Overall, the combination of a KF with the OPE shows the best results. Lastly, the Successive Correction Method (SCM) was applied to spread the bias correction from model grids with surface PM2.5 observations to the grids lacking ground observations by using a radius of influence of 125 km derived from surface observations, which further improves the forecast of surface PM2.5 at the national scale. Our findings provide the foundation for the second part of this study that uses satellite-based aerosol optical depth (AOD) products to further improve the forecast of surface PM2.5 in rural areas by performing statistical analysis of model output.

[Role of Ezh2 in the all-trans retinoic acid induced P19 neural differentiation].

OBJECTIVE: To study the role of Ezh2 in the all-trans retinoic acid RA induced P19 neural differentiation. METHODS: The expression of Ngn1 in the RA induced P19 cells was detected at the mRNA and protein levels using real time RT-PCR and Western blot assays. The binding of Ezh2 and H3K27me3 on the Ngn 1 promoter was analyzed using chromatin immunoprecipitation assay. RESULT: In the RA induced P19 cells, the recruitment of Ezh2 and its methylated substrate H3K27me3 on the promoter of Ngn 1 gene elevated in the first 2 days, and then declined rapidly, followed by the initiation of neuronal differentiation. CONCLUSIONS: Ezh2 produces a repressive histone mark H3K27me3 in the early stage of RA induced P12 cells. By avoiding the premature expression of Ngn1 gene, Ezh2 can ensure the normal differentiation of P19 cells.

Comparison of the life-history parameters and competition outcome with Moina macrocopa between two morphs of Brachionus forficula.

In rotifers, the costs of morphological defenses, especially the development of long spines, have been investigated for several decades. However, the obtained results were inconsistent and the underlying reasons were complicated. Investigations on more species might be helpful to find out the reasons. In the present study, Brachionus forficula was selected as the model organism. The differences in developmental durations, life-table demography, starvation resistant time and the competitive ability with Moina macrocopa were compared between B. forficula with long (LPS) and short (SPS) posterior spines. The results showed that LPS showed relatively longer durations of juvenile stage at 1.0 × 106, 2.0 × 106 and 4.0 × 106 cells/ml Scenedesmus obliquus, and longer embryo stage at 2.0 × 106 cells/ml S. obliquus than SPS. The intrinsic rate of population increase and net reproduction rate were lower in LPS than SPS, suggesting the energy input to reproduction decreased. The starvation resistant time was also reduced in LPS, in comparison to SPS, further supporting that LPS consumed more energy, which might be directed to the development of long spines. All these results revealed that LPS spent more energy for individual growth than SPS, which might be used to develop long spines. Moreover, the maximum population density and population growth rate of LPS were always lower than those of SPS, suggesting that LPS might have a weaker competition ability with M. macrocope than SPS.

LncRNA-LINC00152 down-regulated by miR-376c-3p restricts viability and promotes apoptosis of colorectal cancer cells.

Recent studies have demonstrated that the crucial regulatory roles of long noncoding RNAs (lncRNAs) in tumorigenesis. Expression levels of several lncRNAs are abnormally up-regulated or down-regulated and play a primary role in colorectal cancer (CRC) cell tumorigenesis. However, the potential role and regulatory mechanisms of the novel human lncRNA, LINC00152, in CRC cells are poorly understood. Here, we found that LINC00152 expression was significantly decreased in CRC tissues and CRC cell lines, and this change was more frequent in patients with advanced stage (tumor-node-metastasisi (TNM) III and IV). Overexpression of LINC00152 (LINC000152over) resulted in decreased cell viability and increased apoptosis in CSC cell lines (HT-29 and SW480). Furthermore, decreased Ki-67 and B-cell lymphoma-2 (Bcl-2), and increased Fas, were observed in CSC cells. However, a change in Bax expression was undetected. Interestingly, microRNA (miR)-376c-3p down-regulated the expression of LINC00152 in CSC cells. Overexpression of miR-376c-3p (miR-376c-3pover) enhanced viability and limited apoptosis of CSC cells. In addition, miR-376c-3pover suppressed the effect of LINC00152over on the viability and apoptosis of CSC cells. Taken together, these data indicate that LINC00152 in CSC cells negatively regulated by miR-376c-3p, restricts cell viability and stimulates cell apoptosis, possibly by modulating the expression of Ki-67, Bcl-2, and Fas. MiR-376c-3p/LINC00152 plays an important role in the pathogenesis of CRC and may serve as a potential target for its diagnosis and treatment.

[Expression of recombinant human alanine aminotransferase (ALT) isoenzyme 2 and preparation of anti-ALT2 monoclonal antibody].

AIM: To clone and express human alanine aminotransferase 2 (ALT2) in E.coli Rosetta (DE3), and to prepare monoclonal antibodies(mAb) against ALT2 for diagnostic purpose. METHODS: The gene encoding alanine aminotransferase 2 (ALT2) was cloned from hepatoma carcinoma cell by RT-PCR, and then inserted into pET28a vector. Recombination plasmids (pET28a-ALT2) were transformed into E.coli BL21. Human ALT2 was expressed as His-tagged fusion proteins and purified by immobilized Ni(2+);-affinity chromatography. The purified fusion ALT2 protein was used as an antigen to prepare mAb against it. RESULTS: The fusion ALT2 protein was expressed in recombinant E.coli Rosetta (DE3). The enzymatic activity of purified His-tag ALT2 is over 10 000 U/L. Mice were immunized with the purified fusion ALT2 protein, and 5 mAbs against ALT2 were generated. CONCLUSION: Two mAbs with high specificity for ALT2 were selected for further quantitative diagnostic reagent development.