Physical characteristics of nanoparticles emitted from incense smoke

Incense is habitually burned in various religious settings ranging from the Eastern temples to the Western churches and in residential homes of their devotees, representing one of the most significant sources of combustion-derived particulate matter in indoor air. Incense smoke has been known to be associated with adverse health effects, which could be due to the release of the submicron-sized particles, including ultrafine and nanoparticles. However, there is currently a lack of information available in the literature on the emission rates of particles from incense smoke in terms of their particle number, a metric generally regarded as a better indicator of health risks rather than the particle mass. In this study, real-time characterization of the size distribution and number concentration of sub-micrometer-sized particles (5.6–560 nm) emitted from incense smoke was made, for the first time, for four different brands of sandalwood and aloeswood incense sticks commonly used by different religious groups. In addition, the respective emission rates were determined on hourly and mass basis based on mass balance equations. The measurements showed that the particle emission rates ranged from 5.10 × 10¹² to 1.42 × 10¹³ h^–1 or 3.66 × 10¹² to 1.23 × 10¹³ g^–1 and that the peak diameters varied from 93.1 to 143.3 nm. Airborne particles in the nanometer range (5.6–50 nm), in the ultrafine range (50–100 nm) and in the accumulation mode range (100–560 nm) accounted for 1% to 6%, 16% to 55% and 40% to 60% of the total particle counts, respectively, depending on the brand of incense sticks. To assess the potential health threat due to inhalation of particles released from incense burning, the number of particles of different sizes that can be possibly deposited in the respiratory tract were evaluated for an exposed individual based on known deposition fractions in the literature. The findings indicate that incense smoke may pose adverse health effects depending on exposure duration and intensity.     

Trilinolein,a Natural Triacylglycerol,Protects Cerebral Ischemia through Inhibition of Neuronal Apoptosis and Ameliorates Intimal Hyperplasia via Attenuation of Migration and Modulation of Matrix Metalloproteinase-2 and RAS/MEK/ERK Signaling Pathway in VSMCs

Cerebrovascular disease is one of the leading causes of disability and death worldwide, and seeking a potential treatment is essential. Trilinolein (TriL) is a natural triacylglycerol presented in several plants. The effects of TriL on cerebrovascular diseases such as cerebral ischemia and carotid stenosis have never been studied. Accordingly, we investigated the protection of TriL on cerebral ischemia/reperfusion (I/R) and vascular smooth muscle cell (VSMC) migration in vivo and in vitro. The cerebral infarction area, the intima to media area (I/M ratio), and proliferating cell nuclear antigen (PCNA)-staining of the carotid artery were measured. Platelet-derived growth factor (PDGF)-BB-stimulated A7r5 cell migration and potential mechanisms of TriL were investigated by wound healing, transwell, and Western blotting. TriL (50, 100, and 200 mg/kg, p.o.) reduced: the cerebral infarction area; neurological deficit; TUNEL-positive apoptosis; intimal hyperplasia; and PCNA-positive cells in rodents. TriL (5, 10, and 20 µM) significantly inhibited PDGF-BB-stimulated A7r5 cell migration and reduced matrix metalloproteinase-2 (MMP-2), Ras, MEK, and p-ERK protein levels in PDGF-BB-stimulated A7r5 cells. TriL is protective in models of I/R-induced brain injury, carotid artery ligation-induced intimal hyperplasia, and VSMC migration both in vivo and in vitro. TriL could be potentially efficacious in preventing cerebral ischemia and cerebrovascular diseases.     

Kirkendall porosity in barium titanate–strontium titanate diffusion couple

Inter-diffusion between perovskites BaTiO₃ and SrTiO₃ diffusion couple has been studied by determining the crystalline phases and analyzing the microchemistry and microstructure of undoped BaTiO₃–SrTiO₃ stacks sintered at 1250 °C in air. The Kirkendall effect manifested by: (1) an inter-diffusion zone containing (Ba_1−xSr_x)TiO₃ and (Sr_1−xBa_x)TiO₃ solid solutions, (2) the migration of the initial BaTiO₃–SrTiO₃ interface, and (3) the Kirkendall porosity was observed. The inter-diffused regions on both sides of the initial interface contain grains exhibiting the characteristic core–shell structure with distinctive solute contents between core and shell. TiO₂-rich polytitanates, notably Ba₄Ti₁₃O₃₀ and Ba₆Ti₁₇O₄₀ containing a minor amount of Sr from inter-diffusion, have been detected at the BaTiO₃ side near the initial BaTiO₃–SrTiO₃ interface. An analogy between the BaTiO₃–SrTiO₃ diffusion couple and Kirkendall's original α-brass-Cu couple is presented.     

Solar water oxidation in sputter-deposited nanocrystalline WO3 photoanodes via tuning of Ar:O2 flow rate combinations

Thin film WO₃ photoanodes were prepared by reactive sputtering in Ar and O₂ gas mixtures of various flow rate combinations. Furnace annealed films were nanocrystalline monoclinic WO₃ with (002), (020) and (200) plane orientations. Water oxidation in 0.33 M H₂SO₄ electrolyte under simulated solar illumination showed that photoanodes deposited in highest Ar and O₂ flow rate combinations exhibited highest photocurrent of 4.1 mA cm⁻² (at 1.3 V vs Ag/AgCl) compared to 3–3.8 mA cm⁻² for photoanodes deposited in lower flow rate combinations. The higher photocurrents were ascribed to lower bulk resistivity and charge transfer resistance at the WO₃/electrolyte interface. These photoanodes consisted of randomly oriented (002), (020) and (200) planes in contrast to the preferentially orientated (002) and (200) planes of photoanodes which were highly resistive with poorer photocurrent responses. These results were interpreted in terms of the effects of Ar:O₂ flow rate combinations on the distribution of oxygen vacancies and formation of crystallographic shear planes in the sputtered films.     

紫外吸收剂插层蒙脱土对沥青老化性能的影响

采用有机插层剂对钠基蒙脱土进行有机化处理,得到有机蒙脱土(OMMT),分别将其与不同类型的紫外吸收剂(UVA)进行复合插层,制备得到UVA插层OMMT,并通过X射线衍射试验对UVA插层OMMT的结构进行了表征;同时通过熔融共混法,制备了 UVA插层OMMT改性沥青,并采用常规性能试验、薄膜烘箱老化试验和紫外光(UV)老...     

Characterization and source apportionment of particulate matter < or = 2.5 micrometer in Sumatra, Indonesia, during a recent peat fire episode

An intensive field study was conducted in Sumatra, Indonesia, during a peat fire episode to investigate the physical and chemical characteristics of particulate emissions in peat smoke and to provide necessary data for source-receptor analyses. Ambient air sampling was carried out at three different sites located at varying distances from the peatfires to determine changes in mass and number concentrations of PM2.5 and its chemical composition (carbonaceous and nitrogenous materials, polycyclic aromatic hydrocarbons, water-soluble inorganic and organic ions, and total and water-soluble metals). The three sites represent a rural site directly affected by the local peat combustion, a semirural site, and an urban site situated downwind of the peat fires. The mass concentration of PM2.5 and the number concentration of airborne particles were as high as 1600 microg/m3 and 1.7 x 10(5) cm(-3), respectively, in the vicinity of peat fires. The major components of PM2.5 in peat smoke haze were carbonaceous particles, particularly organic carbon, NO3-, and SO4(2-), while the less abundant constituents included ions such as NH4+, NO2-, Na+, K+, organic acids, and metals such as Al, Fe, and Ti. Source apportionment by chemical mass balance receptor modeling indicates that peat smoke can travel long distances and significantly affect the air quality at locations downwind.