Impact of shipping emissions regulation on urban aerosol composition changes revealed by receptor and numerical modelling.

Various shipping emissions controls have recently been implemented at both local and national scales. However, it is difficult to track the effect of these on PM2.5 levels, owing to the non-linear relationship that exists between changes in precursor emissions and PM components. Positive Matrix Factorisation (PMF) identifies that a switch to cleaner fuels since January 2020 results in considerable reductions in shipping-source-related PM2.5, especially sulphate aerosols and metals (V and Ni), not only at a port site but also at an urban background site. CMAQ sensitivity analysis reveals that the reduction of secondary inorganic aerosols (SIA) further extends to inland areas downwind from ports. In addition, mitigation of secondary organic aerosols (SOA) in coastal urban areas can be anticipated either from the results of receptor modelling or from CMAQ simulations. The results in this study show the possibility of obtaining human health benefits in coastal cities through shipping emission controls.

Emissions from ships' activities in the anchorage zone: A potential source of sub-micron aerosols in port areas.

Busan Port is among the world's top ten most air-polluted ports, but the role of the anchorage zone as a significant contributor to pollution has not been studied. To assess the emission characteristics of sub-micron aerosols, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in Busan, South Korea from September 10 to October 6, 2020. The concentration of all AMS-identified species and black carbon were highest when the winds came from the anchorage zone (11.9 µg·m-3) and lowest with winds from the open ocean (6.64 µg·m-3). The positive matrix factorization model identified one hydrocarbon-like organic aerosol (HOA) and two oxygenated organic aerosol (OOA) sources. HOAs were highest with winds from Busan Port, while oxidized OOAs were predominant with winds from the anchorage zone (less oxidized) and the open ocean (more oxidized). We calculated the emissions from the anchorage zone using ship activity data and compared them to the total emissions from Busan Port. Our results suggest that emissions from ship activities in the anchorage zone should be considered a significant source of pollution in the Busan Port area, especially given the substantial contributions of gaseous emissions (NOx: 8.78%; volatile organic compounds: 7.52%) and their oxidized moieties as secondary aerosols.

Sedimentation history and excess metal deposition in estuarine barrier-island system of the Nakdong River, South Korea.

Human activities, such as dam construction and reclamation, can affect sedimentation rates as well as sediment topography and transport in estuaries such as the Nakdong River Estuary. To investigate the sedimentation history, two sediment cores (1-2 m long) were sampled in tidal flats of the estuary. In addition, surface sediments were collected to study present sedimentation environments that appear to be three environments locally: 1) fine-grained sediment deposition; 2) sediments under stronger hydraulic energy; and 3) sandy sediments with good sorting. At the fine sediment deposition, environmental sensitive fraction of elements (Cu, Pb, As, and Co) show an increased sedimentation flux after the dam construction. On the other hand, organic matter-normalized Pb-210 concentrations in sediment core reveal that marine-originated organic matter is predominant in the upper ~45 cm of sediment layers, indicating a significant change in sedimentation history related to massive sedimentation within the Nakdong River Estuary.

Opposite response modes of NADW dynamics to obliquity forcing during the late Paleogene.

Although the responses of North Atlantic Deep Water (NADW) is deeply connected to orbital rhythms, those under different tectonic and atmospheric boundary conditions remain unknown. Here, we report suborbitally resolved benthic foraminiferal stable isotope data from J-anomaly Ridge in the North Atlantic from ca. 26.4-26.0 Ma. Our results indicate that the formation of NADW during that time interval was increased during the obliquity-paced interglacial periods, similar to in the Plio-Pleistocene. During the late Oligocene, the interglacial poleward shifts of the stronger westerlies in the southern hemisphere, which occurred due to the higher thermal contrasts near the upper limit of the troposphere, reinforced the Antarctic Circumpolar Current (ACC) and, in turn, the Atlantic meridional overturning circulation (AMOC). However, such a response mode in deep ocean circulation did not occur during the middle Eocene because of different tectonic boundary conditions and the immature states of the ACC. Instead, the middle Eocene interglacial conditions weakened the formation of the proto-type NADW due to less heat loss rate in high-latitude regions of the North Atlantic during high obliquity periods. Our findings highlight the different responses of deep ocean circulation to orbital forcing and show that climate feedbacks can be largely sensitive to boundary conditions.

Preparation, characterization, and evaluation of celecoxib eutectic mixtures with adipic acid/saccharin for improvement of wettability and dissolution rate.

Celecoxib (CEL) is a selective cyclooxygenase-2 (COX-2) inhibitor therapeutically indicated for the treatment of rheumatoid arthritis, osteoarthritis, acute pain, and inflammation. However, its poor solubility and dissolution rate significantly hinders its broader application. In this study, eutectic mixtures, as binary pharmaceutical compositions of CEL with adipic acid (ADI) and saccharin (SAC), were identified through a phase diagram and Tammann's triangle intended to improve the wettability and dissolution rate of poorly water-soluble CEL. The contact angles at 0s in the liquid-solid interface were approximately θs (theta) 79.7 ±â€¯0.50° and 86.65 ±â€¯0.45° for CEL-ADI and CEL-SAC, respectively, which were much lower than the value obtained for CEL (92.05 ±â€¯0.75° θ). Moreover, a comparison of the disk intrinsic dissolution rate and powder dissolution properties demonstrated that eutectic mixtures significantly increased the dissolution rate compared with CEL and physical mixtures. A general relationship was elucidated and indicated that the dissolution rate was increased as the contact angle decreased (correlation coefficient, r = 0.9966 ±â€¯0.0031). Therefore, CEL-ADI and CEL-SAC eutectics may offer a novel formulation strategy to enhance the solubility and oral bioavailability of CEL.

Enhancing the solubility and bioavailability of poorly water-soluble drugs using supercritical antisolvent (SAS) process.

Poor water solubility and poor bioavailability are problems with many pharmaceuticals. Increasing surface area by micronization is an effective strategy to overcome these problems, but conventional techniques often utilize solvents and harsh processing, which restricts their use. Newer, green technologies, such as supercritical fluid (SCF)-assisted particle formation, can produce solvent-free products under relatively mild conditions, offering many advantages over conventional methods. The antisolvent properties of the SCFs used for microparticle and nanoparticle formation have generated great interest in recent years, because the kinetics of the precipitation process and morphologies of the particles can be accurately controlled. The characteristics of the supercritical antisolvent (SAS) technique make it an ideal tool for enhancing the solubility and bioavailability of poorly water-soluble drugs. This review article focuses on SCFs and their properties, as well as the fundamentals of overcoming poorly water-soluble drug properties by micronization, crystal morphology control, and formation of composite solid dispersion nanoparticles with polymers and/or surfactants. This article also presents an overview of the main aspects of the SAS-assisted particle precipitation process, its mechanism, and parameters, as well as our own experiences, recent advances, and trends in development.

Cyclosporine Amicellar delivery system for dry eyes.

BACKGROUND: The objectives of this study were to develop stable cyclosporine A (CsA) ophthalmic micelle solutions for dry-eye syndrome and evaluate their physicochemical properties and therapeutic efficacy. MATERIALS AND METHODS: CsA-micelle solutions (MS-CsA) were created by a simple method with Cremophor EL, ethanol, and phosphate buffer. We investigated the particle size, pH, and osmolarity. In addition, long-term physical and chemical stability for MS-CsA was observed. To confirm the therapeutic efficacy, tear production in dry eye-induced rabbits was evaluated using the Schirmer tear test (STT). When compared to a commercial product, Restasis, MS-CsA demonstrated improvement in goblet-cell density and conjunctival epithelial morphology, as demonstrated in histological hematoxylin and eosin staining. RESULTS: MS-CsA had a smaller particle size (average diameter 14-18 nm) and a narrow size distribution. Physicochemical parameters, such as particle size, pH, osmolarity, and remaining CsA concentration were all within the expected range of 60 days. STT scores significantly improved in MS-CsA treated groups (P<0.05) in comparison to those of the Restasis-treated group. The number of goblet cells for rabbit conjunctivas after the administration of MS-CsA was 94.83±8.38, a significantly higher result than the 65.17±11.51 seen with Restasis. The conjunctival epithelial morphology of dry eye-induced rabbits thinned with loss of goblet cells. However, after 5 days of treatment with drug formulations, rabbit conjunctivas recovered epithelia and showed a relative increase in the number of goblet cells. CONCLUSION: The results of this study indicate the potential use of a novel MS for the ophthalmic delivery of CsA in treating dry eyes.

Historical trend in heavy metal pollution in core sediments from the Masan Bay, Korea.

The spatiotemporal distribution and their mass accumulation rate (MAR) of heavy metals were investigated to evaluate the time-dependent historical trends of heavy metal concentration. The three short cores used for this study were collected from the catchment area (MS-PC5, 60cm length), the central part (MS-PC4, 40cm length) and the offshore (MS-PC2, 60cm length) of the Masan Bay, Korea. The concentration of heavy metals (Co, Ni, Cu, Zn, Cr and Pb) in catchment area is as much as 1.5-2 times higher than central part of the Bay, and about 2 times higher than offshore area approximately. In particular, MAR of metals (Cu, Zn and Pb) show clear spatiotemporal variation, so that MAR's of heavy metal may provide more accurate information in evaluating the degree of pollution. Temporally, the heavy metal concentration had been increased since the late 1970s, but it seems to decrease again since the 2004yr in catchment area. This may came from concentrated efforts for the government to reduce industrial waste release.

Oceanobacillus profundus sp. nov., isolated from a deep-sea sediment core.

A halotolerant, facultatively alkaliphilic bacterium, designated CL-MP28T, was isolated from the surface of a sediment core sample collected at a depth of 2247 m in the Ulleung Basin of the East Sea, Korea. Phylogenetic analysis of the 16S rRNA gene sequence of strain CL-MP28T revealed an affiliation with the genus Oceanobacillus. The sequence similarities between the isolate and type strains of members of the genus Oceanobacillus were in the range 95.0-96.0 %, indicating that strain CL-MP28T represented a novel species within the genus. The strain was found to be Gram-positive, rod-shaped and motile by means of peritrichous flagella and was shown to produce ellipsoidal spores. The strain was strictly aerobic and able to grow with NaCl at concentrations in the range 0-14 % (w/v) at pH 7.5. The strain grew at temperatures of 15-42 degrees C and at pH 6.5-9.5. The major fatty acids were anteiso-C(15 : 0) (64.9 %), anteiso-C(17 : 0) (11.9 %) and iso-C(16 : 0) (7.7 %). The major isoprenoid quinone was MK-7. The DNA G+C content was 40.2 mol%. According to the 16S rRNA gene sequence, DNA-DNA relatedness and physiological data and the fatty acid composition, CL-MP28T could be assigned to the genus Oceanobacillus, but is distinguishable from the recognized species of this genus. Strain CL-MP28T therefore represents a novel species within the genus Oceanobacillus, for which the name Oceanobacillus profundus sp. nov. is proposed. The type strain is CL-MP28T (=KCCM 42318T=DSM 18246T).