Identification of sources of elevated concentrations of polycyclic aromatic hydrocarbons in an industrial area in Tianjin, China

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104 soil samples from this area ranged from 68.7 to 5,590 ng g (-aEuro parts per thousand 1) dry weight with a mean of a16PAHs 814 +/- 813 ng g (-aEuro parts per thousand 1), which suggests that there exists mid to high levels of PAH contamination. The concentration of a16PAHs in one soil sample from Tianjin Port was exceptionally high (48,700 ng g (-aEuro parts per thousand 1)). Ninety-three of the 105 soil samples were considered to be contaminated with PAHs (> 200 ng g (-aEuro parts per thousand 1)), and 25 were heavily polluted (> 1,000 ng g (-aEuro parts per thousand 1)). The sites with high PAHs concentration are mainly distributed around chemical industry parks and near highways. Two low molecular weight PAHs, naphthalene and phenanthrene, were the dominant components in the soil samples, which accounted for 22.1% and 10.7% of the a16PAHs concentration, respectively. According to the observed molecular indices, house heating in winter, straw stalk combustion in open areas after harvest, and petroleum input were common sources of PAHs in this area, while factory discharge and vehicle exhaust were the major sources around chemical industrial parks and near highways. Biological processes were probably another main source of low molecular weight PAHs

Regional differences and sources of organochlorine pesticides in soils surrounding chemical industrial parks

Concentrations of organochlorine pesticides (OCPs; dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB)) were investigated in 105 soil samples collected in vicinity of the chemical industrial parks in Tianjin, China. OCP concentrations significantly varied in the study area, high HCH and DDT levels were found close to the chemical industrial parks. The intensity of agricultural activity and distance from the potential OCP emitters have important influences on the OCP residue distributions. Principal component analysis indicates that HCH pollution is a mix of historical technical HCH and current lindane pollution and DDT pollution input is only due to technical DDT sources. The significant correlations of OCP compounds reveal that HCHs, DDTs and HCB could have some similar sources of origin

Process intensification of BaSO4 nanoparticle preparation with agitation of microbubbles

AbstractThis study presents a novel technique for the controllable preparation of BaSO4 nanoparticles via the introduction of microbubbles into the reaction system. A high-concentration system based on barite industry was used, with saturated aqueous Na2SO4 and BaS solutions as the reactants. Microbubbles were generated by a membrane dispersion microreactor. The mixing performance was characterized using parallel competing reactions. The effects of various operation parameters on the nanoparticles were determined, and the reaction conditions were optimized. The results showed that the mixing performance could be improved by introducing microbubbles. The BaSO4 nanoparticles were controllably prepared, with a relatively narrow size distribution. The average particle size could likewise be reduced to approximately 40nm. A dimensionless micromixing scale of the microbubble flow was defined, and a model for predicting the BaSO4 particle size was proposed. The calculated results were consistent with the experimental data

Surgical excision promotes tumor growth and metastasis by promoting expression of MMP-9 and VEGF in a breast cancer model

Surgery is still the main curative therapeutic modality for breast cancer. Although surgery often results in the successful removal of the primary tumor, its process could increase the risk of metastases of residual cancer cells. Understanding of the connection between breast cancer metastasis and surgical wound will lead to the establishment of a proper treatment strategy for postoperative cancer patient. Aim: To study the influence of surgical procedure on the metastasis of primary breast cancer. Methods: We established MDA-MB-435 human breast cancer xenograft model. Levels of Pro-matrix metalloproteinase 9 (Pro-MMP-9) and vascular endothelial growth factor (VEGF) in host serum and tumors were tested at different time points with ELISA and zymography and correlated to tumor growth and postoperative metastasis. Results: Our study demonstrated surgical wound had promoting effect on tumor growth and pulmonary metastasis of human breast cells, if tumor cells remain in bodies. This effect might be related to the postoperative interaction of cancer and host cells, which resulted in expression of Pro-MMP-9. Surgical process could also increase the VEGF expression in tumor tissues. Conclusions: Surgical wound-produced host Pro-MMP-9 and tumor cell VEGF might be important mediators leading to metastasis of residual breast cancer after surgery.Хирургическое лечение до сих пор остается главным терапевтическим подходом при лечении больных раком молочной железы. Хотя хирургическое удаление опухоли в большинстве случаев достаточно эффективно, в то же время оно может увеличить риск метастазирования остаточных опухолевых клеток. Понимание связи между метастазированием при раке молочной железы и операционной раной позволит выбрать наилучшую стратегию постоперационного лечения. Цель: определить влияние хирургического вмешательства на метастазирование опухоли. Методы: была создана модель рака молочной железы человека в виде ксенотрансплантата MDA-MB-435. Уровень Pro-матричной металлопротеиназы 9 (Pro-MMP-9) и фактора роста эндотелия сосудов (VEGF) в сыворотке реципиента и опухолях оценивались в разные временные промежутки методом ELISA и зимографии. При этом определяли наличие корелляции между этими показа- и зимографии. При этом определяли наличие корелляции между этими показа и зимографии. При этом определяли наличие корелляции между этими показателями, ростом опухоли и постоперационными метастазами. Результаты: было показано, что операционная рана способствует росту опухоли молочной железы и ее метастазированию в легкие в случае, когда при удалении опухоли в ране остаются опухолевые клетки. Это может быть связано с постоперационным взаимодействием опухолевых и окружающих их нормальных клеток, которое приводит к экспрессии Pro-MMP-9. Удаление опухоли может также способствовать увеличению экспрессии VEGF опухолевыми клетками. Выводы: Pro-MMP-9, экспрессируемый нормальными клетками, окружающими постоперационную рану, а также VEGF, продуцируемый опухолевыми клетками, могут быть важными медиаторами метастазирования остаточных опухолевых клеток после хирургического вмешательства

Chemically dealloyed Fe-based metallic glass with void channels-like architecture for highly enhanced peroxymonosulfate activation in catalysis

Metallic glasses (MGs) with their intrinsic disordered atomic structure and widely controllable atomic components have recently emerged as fascinating functional materials in wastewater treatment. Compared to crystalline alloys, the less-noble atomic components in monolithic metallic glass are more efficient to be selectively dissolved during dealloying process. This work reported a facile chemical dealloying approach to fabricate a void channels-like structured MG with the elemental components of Fe73.5Si13.5B9Cu1Nb3 for methylene blue (MB) degradation. Results indicated that the dealloyed Fe73.5Si13.5B9Cu1Nb3 MGs with the void channels-like morphology presented a significant improvement of catalytic efficiency and reusability. The dye degradation reaction rate (kobs) of the dealloyed Fe73.5Si13.5B9Cu1Nb3 MGs presented 3 times higher than their as-spun MGs. More importantly, the dealloyed Fe73.5Si13.5B9Cu1Nb3 MGs can be reused up to 25 times without significantly loosing catalytic efficiency. It was also found that the dealloyed Fe73.5Si13.5B9Cu1Nb3 MGs exhibited a greater corrosion resistance in the simulated dye solution compared to the as-spun ribbons, demonstrating a robust self-healing ability in catalytic activity. This work provides a novel view for designing MG catalysts with high efficiency and stability in worldwide energy and environmental concerns

Entanglement and four wave mixing effects in the dissipation free nonlinear interaction of two photons at a single atom

We investigate the nonlinear interaction between two photons in a single input pulse at an atomic two level nonlinearity. A one dimensional model for the propagation of light to and from the atom is used to describe the precise spatiotemporal coherence of the two photon state. It is shown that the interaction generates spatiotemporal entanglement in the output state similar to the entanglement observed in parametric downconversion. A method of generating photon pairs from coherent pump light using this quantum mechanical four wave mixing process is proposed.Comment: 10 pages, including 3 figures, correction in eq.(7), updated references, final version for publication in PR

Generation of spatial antibunching with free propagating twin beams

We propose and implement a novel method to produce a spatial anti-bunched field with free propagating twin beams from spontaneous parametric down-conversion. The method consists in changing the spatial propagation by manipulating the transverse degrees of freedom through reflections of one of the twin beams. Our method use reflective elements eliminating losses from absorption by the objects inserted in the beams.Comment: Submitted for publication in Phys. Rev.

Effects of Sc and Zr on the texture and mechanical anisotropy of high strength Al - Zn - Mg alloy sheets

Texture, mechanical anisotropy and microstructure of aged Al–Zn–Mg, Al–Zn–Mg–0.1Sc–0.1Zr and Al–Zn–Mg–0.25Sc–0.1Zr (wt.%) alloy sheets were investigated by tensile tests and electron microscopy. Sc and Zr additions do not change the texture of homogenized and cold rolled alloys, but transfer the cube texture of the aged Al–Zn–Mg alloy into -fiber rolling texture. With increasing Sc and Zr additions, the strength significantly increases, and mechanical anisotropy is enhanced. The strength is highest parallel to the rolling direction, whereas it is lowest at a 45° angle to the rolling direction. The higher strength is mainly due to grain boundary strengthening and precipitation strengthening caused by Al₃ScxZr₁₋x nano-particles. The stronger mechanical anisotropy is ascribed to the rolling texture, due to the inhibitory effect of Al₃ScxZr₁₋x on recrystallization. A new model was successfully established to reveal the interrelation between Sc and Zr additions, texture and yield strength anisotropy of Al–Zn–Mg sheets

Respuestas del δ13C foliar y características foliares a la precipitación y temperatura en un ecosistema árido del noroeste de China

El δ13C foliar es ampliamente usado para explicar estrategias relacionadas con la disponibilidad de recursos en diferentes ambientes. Sin embargo, la respuesta conjunta del δ13C foliar a la precipitación y temperatura así como la relación entre el δ13C foliar y las características foliares no están claras. El δ13C foliar y su relación con las características foliares [tamaño de hoja (LS), longitud foliar (LL), ancho foliar (LW), relación entre la longitud y el ancho foliar (L:W), área foliar específica (SLA) y concentración de N foliar (en una base de peso seco) (Nmass)] fueron investigadas en la especie de arbusto dominante Nitraria tangutorum Bobr en la región árida (Dengkou y Minqin) del noroeste de China. El estudio se efectuó bajo condiciones de varias cantidades de precipitación simuladas (PGS) y temperaturas ambientales (TGS) en las estaciones de crecimiento de 2008, 2009 y 2010. Los resultados mostraron que LS, LW, LL, SLA y Nmass se incrementaron significativamente cuando las cantidades de PGS se incrementaron, pero hubo tendencias de reducción en dichas características cuando las TGS aumentaron. Sin embargo, la mayoría de las relaciones negativas entre las características foliares y las TGS no fueron obvias en Minqin. En ambos sitios, L:W se incrementó cuando las PGS y TGS aumentaron. Hubo un cambio en la relación negativa entre el δ13C foliar-PGS a través de Minqin y Dengkou, lo cual condujo a la falta de efectos de la precipitación en el δ13C foliar a través de ambos sitios, y mayor δ13C foliar a menor precipitación en Minqin. A través de Minqin y Dengkou, PGS solo pudo explicar un 14% de la variación en el δ13C foliar. La combinación de PGS y TGS pudo explicar un 64% de la variación en el δ13C foliar. Las características foliares (LW y L:W) mejoraron aún más la estimación del δ13C foliar. Las combinaciones de PGS, TGS, LW y L:W pudieron explicar un 84% de la variación en el δ13C foliar. Nuestro estudio demostró la importancia de las características foliares en explorar las respuestas del δ13C foliar a cambios globales en ecosistemas áridos.Leaf δ13C is widely used to explain plant strategies related to resource availability in different environments. To understand the coupled response of leaf δ13C to precipitation, temperature and the relationship between leaf δ13C and leaf traits in arid ecosystems, the leaf δ13C and leaf traits (leaf size (LS), leaf length (LL), leaf width (LW), leaf length to width ratio (L:W), specific leaf area (SLA) and mass-based leaf nitrogen concentration (Nmass)) of Nitraria tangutorum Bobr. under simulated increasing precipitation (PGS) and ambient temperature (TGS) in plant growing season from 2008 to 2010 and the relationships between leaf δ13C and leaf traits were investigated in the arid region (Dengkou and Minqin) of northwestern China. Our results showed that LS, LW, LL, SLA and Nmass significantly increased with increasing PGS, but had downward tendencies with increasing TGS although the majority of the negative relationships between leaf traits and TGS were not obvious in Minqin. At the two study sites, L:W increased simultaneously with increasing PGS and TGS. There was a shift in the negative leaf δ13C-PGS relationship across Minqin and Dengkou, which conduce to the lacking effect of precipitation on leaf δ13C across the two sites and higher leaf δ13C in lower precipitation fields in Minqin. Across Minqin and Dengkou, PGS could only explain 14% of the variation in leaf δ13C. The combinations of PGS and TGS could explain 64% of the variation in leaf δ13C. Leaf traits (LW and L:W) could be used to further improve the estimation of leaf δ13C. The combinations of PGS, TGS, LW and L:W could explain 84 % of the variation in leaf δ13C. Our study demonstrated the importance of leaf traits in exploring the responses of leaf δ13C to global changes in arid ecosystems.Fil: Xin, Z.M.. Chinese Academy of Forestry. Institute of Desertification Studies; China. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Liu, M.H.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Lu, Q.. Chinese Academy of Forestry. Institute of Desertification Studies; China. State Forestry Administration. Kumtag Desert Ecosystem Research Station; ChinaFil: Busso, Carlos Alberto. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. State Forestry Administration. Kumtag Desert Ecosystem Research Station; ChinaFil: Zhu, Y.J.. State Forestry Administration. Kumtag Desert Ecosystem Research Station; China. Chinese Academy of Forestry. Institute of Desertification Studies; ChinaFil: Li, Z.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Huang, Y.R.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Li, X.L.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Luo, F.M.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Bao, F.. Chinese Academy of Forestry. Institute of Desertification Studies; ChinaFil: Qian, J.Q.. Henan Agricultural University. College of Forestry; ChinaFil: Li, Y.H.. Chinese Academy of Forestry. Institute of Desertification Studies; China. State Forestry Administration. Kumtag Desert Ecosystem Research Station; Chin

Electroluminescence enhancement in mid-infrared InAsSb resonant cavity light emitting diodes for CO 2 detection

In this work, we demonstrated a mid-infrared resonant cavity light emitting diode (RCLED) operating near 4.2 μm at room temperature, grown lattice-matched on a GaSb substrate by molecular beam epitaxy, suitable for CO 2 gas detection. The device consists of a 1 λ-thick microcavity containing an InAs 0.90 Sb 0.1 active region sandwiched between two high contrast, lattice-matched AlAs 0.08 Sb 0.92 /GaSb distributed Bragg reflector (DBR) mirrors. The electroluminescence emission spectra of the RCLED were recorded over the temperature range from 20 to 300 K and compared with a reference LED without DBR mirrors. The RCLED exhibits a strong emission enhancement due to resonant cavity effects. At room temperature, the peak emission and the integrated peak emission were found to be increased by a factor of ∼ 70 and ∼ 11, respectively, while the total integrated emission enhancement was ∼ × 33. This is the highest resonant cavity enhancement ever reported for a mid-infrared LED operating at this wavelength. Furthermore, the RCLED also exhibits a superior temperature stability of ∼ 0.35 nm/K and a significantly narrower (10×) spectral linewidth. High spectral brightness and temperature stable emission entirely within the fundamental absorption band are attractive characteristics for the development of next generation CO 2 gas sensor instrumentation. © 2019 Author(s)