Ozone production in four major cities of China: sensitivity to ozone precursors and heterogeneous processes

Abstract. Despite a large volume of research over a number of years, our understandings of the key precursors that control tropospheric ozone production and the impacts of heterogeneous processes remain incomplete. In this study, we analyze measurements of ozone and its precursors made at rural/suburban sites downwind of four large Chinese cities – Beijing, Shanghai, Guangzhou and Lanzhou. At each site the same measurement techniques were utilized and a photochemical box model based on the Master Chemical Mechanism (v3.2) was applied, to minimize uncertainties in comparison of the results due to differences in methodology. All four cities suffered from severe ozone pollution. At the rural site of Beijing, export of the well-processed urban plumes contributed to the extremely high ozone levels (up to an hourly value of 286 ppbv), while the pollution observed at the suburban sites of Shanghai, Guangzhou and Lanzhou was characterized by intense in-situ ozone production. The major anthropogenic hydrocarbons were alkenes and aromatics in Beijing and Shanghai, aromatics in Guangzhou, and alkenes in Lanzhou. The ozone production was found to be in a VOCs-limited regime in both Shanghai and Guangzhou, and a mixed regime in Lanzhou. In Shanghai, the ozone formation was most sensitive to aromatics and alkenes, while in Guangzhou aromatics were the predominant ozone precursors. In Lanzhou, either controlling NOx or reducing emissions of olefins from the petrochemical industry would mitigate the local ozone production. The potential impacts of several heterogeneous processes on the ozone formation were assessed. The hydrolysis of dinitrogen pentoxide (N2O5), uptake of the hydroperoxyl radical (HO2) on particles, and surface reactions of NO2 forming nitrous acid (HONO) present considerable sources of uncertainty in the current studies of ozone chemistry. Further efforts are urgently required to better understand these processes and refine atmospheric models

Thylakoid-bound ascorbate peroxidase increases resistance to salt stress and drought in Brassica napus

Reactive oxygen species (ROS) are cellular indicators of stress. In plants, they function as secondary messengers in response to environmental stress. Ascorbate peroxidase (APX) is an important enzyme directly involved in the scavenging of ROS. In this study, we aimed at identifying the function of the Brassica napus thylakoid APX (tAPX). Germination efficiencies of seeds of B. napus plants over expressing tAPX were higher than those of the seeds of the control plants; this was true both on Murashige and Skoog medium with 300 mM mannitol and with 150 mM NaCl. Further experiments showed that 40-day-old seedlings of the control plants turned yellow, withered, and subsequently died, when treated with 150 mM NaCl for 12 days. In contrast, transgenic plants over expressing tAPX survived this treatment and had at least three green leaves at the end of the experiment. When 40-dayold seedlings were withheld water for 10 days, followed by a 2 day recovery, the control plants exhibited smaller leaves and shorter stems in comparison to tAPX-over expressing plants. In addition, compared with control plants, tAPX-overexpressing plants show reduced hydrogen peroxide accumulation and increased APX relative activity. Our results demonstrate that tAPX plays an important role in resistance to salt stress and drought in plants.Key words: tAPX, transgenic lines, Brassica napus, salt stress, water deficiency

A contemplating review on different synthesis methods of 2D-Molybdenum disulfide (MoS2) nanosheets

The current challenges arising from the rapid development in science and technology attracted researchers to focus on the development of new advanced materials like two-dimensional (2D) nanomaterials, which offer exceptional features that can be used to resolve different industrial problems, which include enhancing energy storage and conversion systems, improving electronic and optoelectronic devices, advancing catalysis and sensing applications, enabling flexible and transparent electronics, advancing healthcare technologies, and addressing environmental concerns such as pollution monitoring and remediation. There are many different layered-structure materials on earth. To get the desired form of these materials, various scientific approaches are applied in laboratories and processing industries. As a result, different methods have been developed for the synthesis of 2D materials. Among various 2D materials, molybdenum disulfide (MoS2) is one of the emerging and promising transition metal dichalcogenides (TMDs) materials that has remarkable electrical, magnetic, optical, and mechanical characteristics. Furthermore, MoS2 nanosheets, when incorporated in different materials, produce promising results, such as better catalytic activities, improved hydrogen production, a super-capacitive feature, and enhanced battery performances, etc. Therefore, in this review, we have focused on significant and practical techniques for synthesizing 2D-MoS2 nanosheets developed by different researchers over the years. We comprehensively discuss their applications, characteristics, as well as provide a brief introduction to the physical and chemical properties of 2D MoS2 nanosheets. Furthermore, we address the current challenges associated with the synthesis of these nanosheets. These discussions highlights that the choice of synthesis method mainly relies on factors such as material type, resources, complexity, environmental impact, scalability, cost, and desired properties of 2D MoS2 nanosheets. Additionally, this literature review also outlines future research directions aimed at overcoming these challenges and advancing synthesis processes to enable the economically feasible scaled-up production of 2D MoS2 nanosheets

Electric-field-induced alignment of electrically neutral disk-like particles: modelling and calculation

This work reveals a torque from electric field to electrically neutral flakes that are suspended in a higher electrical conductive matrix. The torque tends to rotate the particles toward an orientation with its long axis parallel to the electric current flow. The alignment enables the anisotropic properties of tiny particles to integrate together and generate desirable macroscale anisotropic properties. The torque was obtained from thermodynamic calculation of electric current free energy at various microstructure configurations. It is significant even when the electrical potential gradient becomes as low as 100 v/m. The changes of electrical, electroplastic and thermal properties during particles alignment were discussed

Creación, re significación y uso de recursos simbólicos y discursivos durante el gobierno de Evo Morales (2006-2019)

Trabajo de conclusión de curso presentado al Instituto Latinoamericano de Economía, Sociedad y Política de la Universidad Federal de Integración Latino Americana, como requisito parcial para acceder a la Licenciatura en Relaciones Internacionales e Integración Orientador: Prof. Dra. Paula Daniela FernandezDurante los trece años de gobierno de Evo Morales (2006-2019) junto a su partido el Movimiento al Socialismo (MAS), se observan grandes contradicciones entre su discurso político de orden indigenista y sus prácticas políticas, algunas que se remiten a formas políticas de gobiernos tradicionales y de corte occidental. En este sentido se pueden apreciar sus herramientas simbólicas y discursivas, que por un lado toman la imagen de Morales como el único camino posible para el “proceso de cambio”, y otros que resignifican elementos del mundo indígena para ser incorporados al ideario del MAS. De este modo el objetivo de este trabajo es describir y analizar los recursos simbólicos y discursivos utilizados por el gobierno de Evo Morales y el MAS en el periodo 2006- 2019 a fin de legitimarse y consolidarse en el poder.Durante os treze anos de governo de Evo Morales (2006-2019) com seu partido, o Movimento ao Socialismo (MAS), existem grandes contradições entre seu discurso político de uma ordem indigenista e suas práticas políticas, algumas que se referem a formas políticas de governos tradicionais e ocidentais. Nesse sentido, podem ser apreciadas suas ferramentas simbólicas e discursivas, que por um lado tomam a imagem de Morales como o único caminho possível para o “processo de mudança” e outras que ressignificam elementos do mundo indígena a serem incorporados à ideologia do MAS. Assim, o objetivo deste trabalho é descrever e analisar os recursos simbólicos e discursivos utilizados pelo governo de Evo Morales e pelo MAS no período 2006-2019 para legitimar e consolidar no poder

Screening for inborn errors of metabolism in high-risk children: a 3-year pilot study in Zhejiang Province, China

<p>Abstract</p> <p>Background</p> <p>Tandem mass spectrometry (MS/MS) has been available in China for 8 years. This technique makes it possible to screen for a wide range of previously unscreened inborn errors of metabolism (IEM) using a single test. This 3-year pilot study investigated the screening, diagnosis, treatment and outcomes of IEM in symptomatic infants and children.</p> <p>Methods</p> <p>All children encountered in the Newborn Screening Center of Zhejiang Province during a 3-year period with symptoms suspicious for IEM were screened for metabolic diseases. Dried blood spots were collected and analyzed by tandem mass spectrometry. The diagnoses were further confirmed by clinical symptoms and biochemical analysis. Neonatal intrahepatic cholestasis caused by citrin deficiency, ornithine transcarbamylase deficiency and primary carnitine deficiency were confirmed by DNA analysis.</p> <p>Results</p> <p>A total of 11,060 symptomatic patients (6,720 boys, 4,340 girls) with a median age of 28.8 months (range: 0.04-168.2 months) were screened. Among these, 62 were diagnosed with IEM, with a detection rate of 0.56%. Thirty-five were males and 27 females and the median age was 3.55 months (range 0.07-143.9 months). Of the 62 patients, 27 (43.5%) had aminoacidemias, 26 (41.9%) had organic acidemias and nine (14.5%) had fatty acid oxidation disorders.</p> <p>Conclusions</p> <p>Because most symptomatic patients are diagnosed at an older age, mental retardation and motor delay are difficult to reverse. Additionally, poor medication compliance reduces the efficacy of treatment. More extensive newborn screening is thus imperative for ensuring early diagnosis and enhancing the treatment efficacy of IEM.</p

Plasmonically Enhanced Reflectance of Heat Radiation from Low-Bandgap Semiconductor Microinclusions

Increased reflectance from the inclusion of highly scattering particles at low volume fractions in an insulating dielectric offers a promising way to reduce radiative thermal losses at high temperatures. Here, we investigate plasmonic resonance driven enhanced scattering from microinclusions of low-bandgap semiconductors (InP, Si, Ge, PbS, InAs and Te) in an insulating composite to tailor its infrared reflectance for minimizing thermal losses from radiative transfer. To this end, we compute the spectral properties of the microcomposites using Monte Carlo modeling and compare them with results from Fresnel equations. The role of particle size-dependent Mie scattering and absorption efficiencies, and, scattering anisotropy are studied to identify the optimal microinclusion size and material parameters for maximizing the reflectance of the thermal radiation. For composites with Si and Ge microinclusions we obtain reflectance efficiencies of 57 - 65% for the incident blackbody radiation from sources at temperatures in the range 400 - 1600 {\deg}C. Furthermore, we observe a broadbanding of the reflectance spectra from the plasmonic resonances due to charge carriers generated from defect states within the semiconductor bandgap. Our results thus open up the possibility of developing efficient high-temperature thermal insulators through use of the low-bandgap semiconductor microinclusions in insulating dielectrics.Comment: Main article (8 Figures and 2 Tables) + Supporting Information (8 Figures

Radiotherapy-induced cell death activates paracrine HMGB1-TLR2 signaling and accelerates pancreatic carcinoma metastasis

Background: Dying cells after irradiation could promote the repopulation of surviving cancer cells leading to tumor recurrence. We aim to define the role of dying cells in promoting pancreatic cancer cells metastasis following radiotherapy.Methods: Using the transwell system as the in vitro co-culture model, a small number of untreated pancreatic cancer cells were seeded in the upper chamber, while a larger number of lethally treated pancreatic cancer cells were seeded in the lower chamber. A series of experiments were conducted to investigate the role of dying-cell-derived HMGB1 on the invasion of pancreatic cancer in vitro and cancer metastasis in vivo. We then designed shRNA knockdown and Western blot assays to detect signaling activity.Results: We found that dying pancreatic cancer cells significantly promote the invasion of pancreatic cancer cells in vitro and cancer metastasis in vivo. HMGB1 gene knockdown attenuated the migration-stimulating effect of irradiated, dying cells on living pancreatic cancer cells. Finally, we showed that dying-cell-derived HMGB1 functions in a paracrine manner to affect cancer-cell migration dependent on acquiring an epithelial-mesenchymal transition (EMT) phenotype and PI3K/pAkt activation. This process is mediated by the receptor for TLR2.Conclusion: Our study indicates that, during radiotherapy, dying pancreatic cancer cells activate paracrine signaling events that promote the mobility of surviving tumor cells. We suggest a strategy to inhibit HMGB1 for preventing pancreatic carcinoma relapse and metastasis