Investigation of the thermal tolerance of silicon-based lateral spin valves.

Improvement in the thermal tolerance of Si-based spin devices is realized by employing thermally stable nonmagnetic (NM) electrodes. For Au/Ta/Al electrodes, intermixing between Al atoms and Au atoms occurs at approximately 300 °C, resulting in the formation of a Au/Si interface. The Au-Si liquid phase is formed and diffuses mainly along an in-plane direction between the Si and AlN capping layers, eventually breaking the MgO layer of the ferromagnetic (FM) metal/MgO electrodes, which is located 7 µm away from the NM electrodes. By changing the layer structure of the NM electrode from Au/Ta/Al to Au/Ta, the thermal tolerance is clearly enhanced. Clear spin transport signals are obtained even after annealing at 400 °C. To investigate the effects of Mg insertion in FM electrodes on thermal tolerance, we also compare the thermal tolerance among Fe/Co/MgO, Fe/Co/Mg/MgO and Fe/Co/MgO/Mg contacts. Although a highly efficient spin injection has been reported by insertion of a thin Mg layer below or above the MgO layer, these thermal tolerances decrease obviously.

Estimating transboundary transported anthropogenic sulfate deposition in Japan using the sulfur isotopic ratio.

High emissions of air pollutants from Northeast Asia are strongly influenced by air quality as well as by ecosystems. This study investigated the spatiotemporal variations in the sulfur isotopic ratio (δ34S) in atmospheric deposition at eleven monitoring stations in Japan from 2011 to 2016 and estimated the amount of transboundary transported anthropogenic sulfate (TRB) deposition using mass balance calculations. The δ34S of sulfate in precipitation ranged from -0.42 to +22.7‰. Sea salt (SS), TRB, and domestic anthropogenic sources (DOM) were the dominant sources of sulfate deposition in Japan. TRB sulfate deposition was largest on the Sea of Japan side, with an annual average value of 1.5 ±â€¯0.3-6.9 ±â€¯0.5 mg m-2 d-1 (36-44%), followed by Mt. Happo (4.5 ±â€¯0.1 mg m-2 d-1; 88%), the Pacific Ocean side (1.5 ±â€¯0.8, 4.3 ±â€¯0.9 mg m-2 d-1; 24-50%), and the remote islands in the North Pacific Ocean (1.1 ±â€¯0.2, 2.0 ±â€¯0.8 mg m-2 d-1; 19-32%). TRB sulfate deposition on the Sea of Japan side was 2-12 times higher in winter and 1-2 times higher in summer than that of DOM. In contrast, TRB sulfate deposition on the Pacific Ocean side was 1.5-3 times higher in summer than in winter due to high precipitation levels. In Tokyo, the annual contribution from DOM sulfate deposition is approximately three times higher than that from TRB. Annual TRB sulfate deposition is lowest at Ogasawara at 1.1 ±â€¯0.2 mg m-2 d-1, and the annual oceanic DMS contribution to sulfate deposition is high, accounting for 1.3 mg m-2 d-1 (20 ±â€¯6%). The contribution of Asian dust was estimated to be 1-5.2 mg m-2 d-1(3-6%), which occurred in a single Asian dust event on the Sea of Japan side.

Time-dependent distinct roles of Toll-like receptor 4 in a house dust mite-induced asthma mouse model.

House dust mites (HDMs) are a common source of allergens that trigger both allergen-specific and innate immune responses in humans. Here, we examined the effect of allergen concentration and the involvement of Toll-like receptor 4 (TLR4) in the process of sensitization to house dust mite allergens in an HDM extract-induced asthma mouse model.　Intranasal administration of HDM extract induced an immunoglobulin E response and eosinophilic inflammation in a dose-dependent manner from 2.5 to 30 µg/dose. In TLR4-knockout mice, the infiltration of eosinophils and neutrophils into the lung was decreased compared with that in wild-type mice in the early phase of inflammation (total of three doses). However, in the late phase of inflammation (total of seven doses), eosinophil infiltration was significantly greater in TLR4-knockout mice than in wild-type mice. This suggests that the roles of TLR4 signaling are different between the early phase and the later phase of HDM allergen-induced inflammation. Thus, innate immune response through TLR4 regulated the response to HDM allergens, and the regulation was altered during the phase of inflammation.

Perfluoroalkyl substances in waters along the Grand Canal, China.

The Grand Canal, also known as the Beijing-Hangzhou Grand Canal, is a UNESCO World Heritage Site and the longest canal in the world. It is an important trunk line of the South-to-North Water Diversion Project in China. The contamination status and spatial distributions of perfluoroalky substances (PFASs) in waters of the Grand Canal were investigated. The total concentrations of PFASs (∑PFASs) range from 7.8 ng/L to 218.0 ng/L, with high ∑PFASs occurring in the southern part of the Grand Canal which is located in a highly urbanized and economically developed region. The dominance of PFOA showed a decreasing trend toward north while shorter chain homologue proportions increased in the northern part of the Canal which mainly traverses underdeveloped and rural areas in Eastern China. Positive correlations were observed between ∑PFASs and the population density as well as GDP per capita. Intersection with large rivers may affect the contamination levels and composition of PFASs in the water of the Grand Canal near the intersection sites.

Particle size specific distribution of perfluoro alkyl substances in atmospheric particulate matter in Asian cities.

Seasonal and local characteristics of perfluorinated alkylated substances (PFASs) were examined using size-segregated particles including an ultrafine range. The examination included sampling and analysis of ambient particles collected at four sites located in different environments in three different countries, Japan (Kanazawa and Okinawa), Hong Kong and India. To minimize the evaporation artefacts derived from PFASs during the sampling, an air sampler that permitted particles smaller than 0.1 µm (PM0.1) to be separated at a moderate pressure drop (<5-15 kPa), was used for all of the air sampling procedures. In the case of Kanazawa, a local city in Japan, the concentration of PFASs was found to be dominated by carboxylates, especially PFOA, PFNA and PFDA regardless of the particle size and sampling period. Ultrafine particles were found to be the largest contributor to the mass fraction of PFCAs, while the maximum PFOS mass fractions were determined to be in the coarse-sized fractions. The seasonal difference in the total PFAS concentration can be largely attributed to precipitation. The results were basically similar for all sites that were examined. The type of land use may be a more influencing factor on the mass fraction of the PFASs than the country of origin. The dependency of PFAS mass fraction on the specific surface of the particle suggests that ultrafine PFAS particles are segregated, not only by gas deposition but could also be segregated by a mechanism involving compositional dependence or the primary source of the particles. Other possible sources of PFASs, other than from traffic are also possible.

Improvement of virus removal by pilot-scale coagulation-ultrafiltration process for wastewater reclamation: Effect of optimization of pH in secondary effluent.

Reclaimed water (i.e., reused advanced-treated wastewater) offers an alternative water resource. To reduce the health risks associated with its use, efficient virus removal such as with advanced wastewater treatment processes is important. Virus removal by coagulation followed by ultrafiltration (UF) for the treatment of drinking water has been well examined. But its efficacy in wastewater reclamation purpose using secondary treated effluent (SE) from wastewater treatment plant (WWTP) as feed water is unclear. Here, we optimized the virus removal efficiency of coagulation-UF in pilot-scale wastewater reclamation plants using SE as feed water, using the F-specific RNA bacteriophage MS2 as a model virus, at two wastewater treatment plants in Japan. We investigated how using coagulation as a pretreatment for UF improved virus removal efficiency. The efficiency varied greatly between SEs. To reveal the cause of the variation, we conducted laboratory-scale batch coagulation experiments. The efficiency of viral coagulation was negatively correlated with the concentration of dissolved organic matter in the feed water. The optimum pH for coagulation differed between SEs, and the efficiency of coagulation could be dramatically improved by optimizing the pH. We confirmed that the virus removal efficiency in the pilot-scale facility actually could be improved by adjusting the pH. In addition, we confirmed that coagulation-sedimentation-UF with pH adjustment could operate stably for more than 30 days at the pilot scale, with a high virus removal rate. Thus, the wastewater reclamation process described here offers promise in terms of reduced health risks and practical operation.

Extensive water ice within Ceres' aqueously altered regolith: Evidence from nuclear spectroscopy.

The surface elemental composition of dwarf planet Ceres constrains its regolith ice content, aqueous alteration processes, and interior evolution. Using nuclear spectroscopy data acquired by NASA's Dawn mission, we determined the concentrations of elemental hydrogen, iron, and potassium on Ceres. The data show that surface materials were processed by the action of water within the interior. The non-icy portion of Ceres' carbon-bearing regolith contains similar amounts of hydrogen to those present in aqueously altered carbonaceous chondrites; however, the concentration of iron on Ceres is lower than in the aforementioned chondrites. This allows for the possibility that Ceres experienced modest ice-rock fractionation, resulting in differences between surface and bulk composition. At mid-to-high latitudes, the regolith contains high concentrations of hydrogen, consistent with broad expanses of water ice, confirming theoretical predictions that ice can survive for billions of years just beneath the surface.

Comparison of ultrasonographic joint and tendon findings in hands between early, treatment-naïve patients with systemic lupus erythematosus and rheumatoid arthritis.

Although both systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) may lead to joint deformity, SLE arthritis is typically non-erosive and often accompanied by Jaccoud's deformity. Therefore, we examined characteristics of joint and tendon lesions in patients with SLE and RA by ultrasonography. Fifteen treatment-naïve SLE patients and 40 treatment-naïve RA patients with joint symptoms were included in this study. The hand joints and related tendons were ultrasonographically examined using grey-scale (GS) and power Doppler (PD). Joint involvement was comparably observed in patients with SLE and RA (80% versus 95%, p = 0.119). However, tendon involvement was more frequent in SLE than in RA (93% versus 65%, p = 0.045), especially in the wrist joints (73% versus 40%, p = 0.037). When we investigated the intensity of US findings, the joint synovitis score (GS + PD) per affected joint was lower in SLE than RA (2.0 versus 2.6, p = 0.019), while tendon inflammation score was not significantly different (2.1 versus 2.2, p = 0.738). Finally, the examination of concordance between joint and tendon involvement in the same finger revealed that joint lesion appeared in only 49% of fingers having tendon involvement in the SLE group, which was significantly less than 74% in the RA group ( p = 0.010). Thus, as compared with RA, SLE arthropathy is characterized by the predominance of tenosynovitis/periextensor tendon inflammation, which is likely to develop independently from joint synovitis.

Dawn arrives at Ceres: Exploration of a small, volatile-rich world.

On 6 March 2015, Dawn arrived at Ceres to find a dark, desiccated surface punctuated by small, bright areas. Parts of Ceres' surface are heavily cratered, but the largest expected craters are absent. Ceres appears gravitationally relaxed at only the longest wavelengths, implying a mechanically strong lithosphere with a weaker deep interior. Ceres' dry exterior displays hydroxylated silicates, including ammoniated clays of endogenous origin. The possibility of abundant volatiles at depth is supported by geomorphologic features such as flat crater floors with pits, lobate flows of materials, and a singular mountain that appears to be an extrusive cryovolcanic dome. On one occasion, Ceres temporarily interacted with the solar wind, producing a bow shock accelerating electrons to energies of tens of kilovolts.

Anti-IL-31 receptor antibody is shown to be a potential therapeutic option for treating itch and dermatitis in mice.

BACKGROUND AND PURPOSE: IL-31, which is described as a pruritogenic cytokine, is linked to the itching that is associated with allergic and non-allergic eczema, but the precise pruritogenic mechanism of IL-31 and its potential as a therapeutic target for atopic dermatitis (AD) have not been determined. EXPERIMENTAL APPROACH: We investigated the effects of existing drugs on the scratching behaviour induced by an i.v. injection of IL-31 to clarify whether IL-31 induced pruritus indirectly. In addition, we studied the effects of an anti-IL-31 receptor α subunit (anti-IL-31 receptor α) neutralizing antibody on chronic pruritus-inducing dermatitis in an AD-like model to determine whether IL-31 not only induces scratching behaviour, but is also the causative factor in an AD phenotype. KEY RESULTS: The scratching behaviour induced by an i.v. injection of IL-31 was inhibited by pretreatment with an anti-IL-31 receptor α-neutralizing antibody. In contrast, it was not inhibited significantly by a non-sedative antihistamine (terfenadine), immunosuppressants (dexamethasone and tacrolimus), or a µ-opioid receptor antagonist (naloxone). The anti-IL-31 receptor α-neutralizing antibody reduced the ear swelling and dermatitis score in a chronic pruritus-inducing AD-like model. Moreover, treatment with the anti-IL-31 receptor α-neutralizing antibody showed therapeutic effects on the dermatitis even if it was injected after the disease had developed. CONCLUSIONS AND IMPLICATIONS: Anti-IL-31 receptor α is a potential novel therapeutic approach for escaping from the itch-scratch cycle and also a treatment for dermatitis in AD.

Decreased immunoglobulin G levels after living-donor liver transplantation is a risk factor for bacterial infection and sepsis.

BACKGROUND: Several studies have suggested an association between post-transplant immunoglobulin (Ig) levels and the development of infection in solid organ transplantation. We therefore conducted exploratory analyses of potential factors associated with bacterial infection/sepsis after living-donor liver transplantation (LDLT). METHODS: Blood samples from 177 recipients who received primary LDLT between September 1999 and November 2011 were available for study. Hypogammaglobulinemia was defined as having at least 1 IgG level <650 mg/dL within 7 days after LDLT. Risk factors for developing post-transplant bacterial infection and sepsis within 3 months after LDLT were analyzed. RESULTS: Fifty (28.2%) recipients experienced bacterial infection within 3 months of LDLT. Eighty-four (47.5%) recipients had hypogammaglobulinemia, although no recipients had hypogammaglobulinemia before LDLT. Hypogammaglobulinemia, undergoing hepaticojejunostomy, and portal pressure at closure >15 mmHg were independent risk factors for developing bacterial infection within 3 months of LDLT (P < 0.0001 P = 0.0008, and P = 0.011, respectively). The odds ratio (OR) and confidence interval (CI) for hypogammaglobulinemia were 4.79 and 2.27-10.7, respectively. Twenty-four (13.6%) recipients developed bacterial sepsis within 3 months. Hypogammaglobulinemia, operative time >14 h, model for end-stage liver disease score >15, and no mycophenolate mofetil use were independent risk factors for developing bacterial sepsis (P = 0.009, P = 0.001, P = 0.003, and P = 0.005, respectively). The OR and CI for hypogammaglobulinemia were 3.83 and 1.38-12.0, respectively. CONCLUSIONS: Hypogammaglobulinemia within 7 days of LDLT was a significant risk factor for post-transplant bacterial infection and sepsis.

The protein Ocular albinism 1 is the orphan GPCR GPR143 and mediates depressor and bradycardic responses to DOPA in the nucleus tractus solitarii.

BACKGROUND AND PURPOSE: L-DOPA is generally considered to alleviate the symptoms of Parkinson's disease by its conversion to dopamine. We have proposed that DOPA is itself a neurotransmitter in the CNS. However, specific receptors for DOPA have not been identified. Recently, the gene product of ocular albinism 1 (OA1) was found to exhibit DOPA-binding activity. Here, we have investigated whether OA1 is a functional receptor of DOPA in the nucleus tractus solitarii (NTS). EXPERIMENTAL APPROACH: We examined immunohistochemical expression of OA1 in the NTS, and the effects of DOPA microinjected into the depressor sites of NTS on blood pressure and heart rate in anaesthetized rats, with or without prior knock-down of OA1 in the NTS, using shRNA against OA1. KEY RESULTS: Using a specific OA1 antibody, OA1-positive cells and nerve fibres were found in the depressor sites of the NTS. OA1 expression in the NTS was markedly suppressed by microinjection into the NTS of adenovirus vectors carrying the relevant shRNA sequences against OA1. In animals treated with OA1 shRNA, depressor and bradycardic responses to DOPA, but not those to glutamate, microinjected into the NTS were blocked. Bilateral injections into the NTS of DOPA cyclohexyl ester, a competitive antagonist against OA1, suppressed phenylephrine-induced bradycardic responses without affecting blood pressure responses. CONCLUSION AND IMPLICATIONS: OA1 acted as a functional receptor for DOPA in the NTS, mediating depressor and bradycardic responses. Our results add to the evidence for a central neurotransmitter role for DOPA, without conversion to dopamine.

Impact of human T cell leukemia virus type 1 in living donor liver transplantation.

Human T cell leukemia virus type 1 (HTLV-1) is an endemic retrovirus in southwestern Japan, which causes adult T cell leukemia (ATL) or HTLV-1 associated myelopathy in a minority of carriers. Here, we investigated the impact of HTLV-1 status in living donor liver transplantation (LDLT). Twenty-six of 329 (7.9%) HTLV-1 carriers underwent primary LDLT. One recipient negative for HTLV-1 before LDLT received a graft from an HTLV-1 positive donor. Eight donors were HTLV-1 positive. Twenty-seven recipients (13 male and 14 female; mean age 52.5 years) were reviewed retrospectively. ATL developed in four recipients who ultimately died. The intervals between LDLT and ATL development ranged from 181 to 1315 days. Of the four ATL recipients, two received grafts from HTLV-1 positive donors and two from negative donors. The 1-, 3- and 5-year HTLV-1 carrier survival rates were 91.3%, 78.3% and 66.3%, respectively. Fulminant hepatic failure as a pretransplant diagnosis and a pretransplant MELD score ≥ 15 was identified as risk factors for ATL development in this study (p = 0.001 and p = 0.041, respectively). In conclusion, LDLT can be performed for HTLV-1 positive recipients. However, when fulminant hepatic failure is diagnosed, LDLT should not be performed until further studies have revealed the mechanisms of ATL development.

Olive oil polyphenol oleuropein inhibits smooth muscle cell proliferation.

OBJECTIVES: The Mediterranean diet, with a high content of olive oil, is associated with a reduced risk of coronary artery disease. The aim of this study was to determine the effect of oleuropein, one of the polyphenols in olive oil, on vascular smooth muscle cell (SMC) proliferation in vitro. DESIGN: This was an experimental study. MATERIALS AND METHODS: Bovine vascular SMCs were cultured in the presence of 100 µM of oleuropein. On days 1, 3 and 5, cell number was counted. Cell cycle analysis was performed by flow cytometry. Cell cycle regulators were assessed by immunoblotting. RESULTS: Cell proliferation in the presence of oleuropein was significantly inhibited by 92%. Cell cycle analysis revealed that oleuropein treatment blocked cells in the G1-S phase compared with the non-treated group. Among G1 phase regulators, retinoblastoma protein, cyclinD, p21 and p27 were not affected by oleuropein, but extracellular signal-regulated kinase 1/2 (ERK1/2) activation was inhibited. Growth of SMC treated with 100 µM of the mitogen-activated protein (MAP) kinase/ERK kinase 1 (MEK1) inhibitor PD98059 was also significantly inhibited by 70%. CONCLUSIONS: Oleuropein inhibited SMC proliferation through a cell cycle block between the G1 and the S phases, which may be regulated by ERK1/2. These results suggest a mechanism by which olive oil consumption may have beneficial effects on cardiovascular mortality by inhibiting SMC proliferation.

Risk factors for portal venous thrombosis after splenectomy in patients with cirrhosis and portal hypertension.

BACKGROUND: Portal venous thrombosis (PVT) is a potentially fatal complication following splenectomy. Its mechanisms and risk factors are poorly understood, especially in patients with cirrhosis and portal hypertension. This study investigated risk factors for PVT following splenectomy in such patients. METHODS: All consecutive patients with cirrhosis who underwent splenectomy in Kyushu University Hospital between 1998 and 2004 were included in this retrospective study. They were divided into two groups based on the presence or absence of postoperative PVT. Preoperative and operative factors were compared, and the relationships between formation of PVT and its independent variables were analysed. In some cases, portal venous flow was measured before and after splenectomy using duplex Doppler ultrasonography. RESULTS: PVT developed after surgery in 17 (24 per cent) of 70 patients studied. Multivariable analysis showed that increased splenic vein diameter and low white cell count were significant independent risk factors for PVT. Portal venous flow after splenectomy was greatly reduced in the PVT group, but not in patients without PVT. CONCLUSION: Large splenic vein diameter and low white cell count are independent risk factors for PVT after splenectomy in patients with cirrhosis and portal hypertension.

An innovative technique for endoscopic submucosal dissection of early gastric cancer using a new spring device.

BACKGROUND AND STUDY AIMS: In recent years, endoscopic submucosal dissection (ESD) has been applied for the treatment of gastric tumors, and the en-bloc resection rate of early gastric cancer has greatly improved. Herein, we introduce spring-assisted ESD, for quicker submucosal dissection. PATIENTS AND METHODS: ESD was carried out in 32 patients (20 men, 12 women; mean age 72.6 years, range 53 - 88 years) for early gastric cancer, with tumors over 10 mm in diameter. The patients were divided retrospectively into two groups (spring-assisted ESD, n = 20; conventional ESD, n = 12). To comparatively evaluate the performance speed of ESD, the circumferential length and the area of the resected specimen were calculated by the approximation formula for ellipse. Then, the circumferential cutting speed, the submucosal dissection speed, and the total ESD speed were calculated as index scores. The scores for spring-assisted ESD and conventional ESD were compared. RESULTS: The mean (+/-SD) circumferential cutting speeds in spring-assisted ESD and conventional ESD were 0.53 +/- 0.27 and 0.60 +/- 0.30 cm/minute, respectively ( P = 0.51). The mean submucosal dissection speeds in spring-assisted ESD and conventional ESD were 0.67 +/- 0.41 and 0.32 +/- 0.24 cm (2)/minute, respectively ( P = 0.005). The mean total ESD speeds in spring-assisted ESD and conventional ESD were 0.25 +/- 0.10 and 0.17 +/- 0.07 cm (2)/minute, respectively ( P = 0.015). The mean total ESD times were 57 and 75 minutes in the spring and conventional group, respectively ( P = 0.30). CONCLUSION: Using the aforementioned indices, we evaluated the performance speed of ESD. Spring-assisted ESD may allow faster submucosal dissection.

Discussion on the application of UV/H(2)O(2), O(3) and O(3)/UV processes as technologies for sewage reuse considering the removal of pharmaceuticals and personal care products.

The applicability of O(3), UV/H(2)O(2) and O(3)/UV treatment processes as technologies for water reuse considering pharmaceuticals and personal care products (PPCPs) removal was investigated. Electrical energies required for the effective removal of various PPCPs in secondary effluent were 0.09 kWh/m(3), 0.54 kWh/m(3) and 1.09 kWh/m(3) for O(3), UV/H(2)O(2) and O(3)/UV treatments, respectively, showing that O(3) treatment is the most cost-effective treatment option for the PPCPs removal. O(3) treatment showed the effective PPCPs removal at O(3) dose of 6 mg/L; however, the formation of bromate is expected for O(3) treatment using O(3) dose of more than 4 mg/L. In particular, bromate formation will be a critical issue when the reclaimed water is used for direct/indirect potable reuses. Therefore, in order to suppress the bromate formation as well as achieve the effective PPCPs removal, O(3)/UV treatment will be recommended. UV/H(2)O(2) treatment will be also a profitable treatment method because no bromate will be formed during the process. The evaluation for ecological risk of PPCPs by the applied processes showed that all the processes could decrease the ecological risk caused by parent PPCPs considerably. This means that the investigated treatment processes can play an important role in reducing unpredictable side effects caused by PPCPs in the aquatic environment.

A pilot study to assess the efficacy of photodynamic therapy for Japanese patients with actinic keratosis in relation to lesion size and histological severity.

BACKGROUND/PURPOSE: Topical 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) is effective for actinic keratosis (AK); few studies have examined Oriental patients. The aim of this study is to assess the efficacy of PDT for the treatment of Japanese AK patients classified by lesion size and histological severity. METHODS: Thirty patients with solitary AK lesions were divided into two groups according to diameter: a small lesion group (SL), diameter < or =10 mm and a larger lesion group (LL), diameter >10 mm, and histological severity: Group I (mild and moderate) and Group II (severe). After application of 20% ALA for 4 h, exposure to an excimer-dye laser at 630 nm was performed at a dose of 50 J/cm(2) three times at an interval of 7 days. Therapeutic effects were assessed and followed for 12 months. RESULTS: In all 10 SL patients, atypical cells disappeared after PDT and did not recur for 12 months. However, for the 20 LL patients, recurrence was seen in 2 of the 14 Group I patients, while 4 of 6 Group II patients showed residual tumor cells after the first PDT session. CONCLUSION: The present study demonstrated that ALA-PDT might be useful for treatment of Japanese AK. The therapeutic outcome might depend on the lesion size and the histopathological severity.

Total fluorine, extractable organic fluorine, perfluorooctane sulfonate and other related fluorochemicals in liver of Indo-Pacific humpback dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides) from South China.

The concentrations of 10 PFCs (perfluorinated compounds: PFOS, PFHxS, PFOSA, N-EtFOSA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, and PFHpA) were measured in liver samples of Indo-Pacific humpback dolphins (Sousa chinensis) (n=10) and finless porpoises (Neophocaena phocaenoides) (n=10) stranded in Hong Kong between 2003 and 2007. PFOS was the dominant PFC in the tissues at concentrations ranging at 26-693 ng/g ww in dolphins and 51.3-262 ng/g ww in porpoises. A newly developed combustion ion chromatography for fluorine was applied to measure total fluorine (TF) and extractable organic fluorine (EOF) in these liver samples to understand PFC contamination using the concept of mass balance analysis. Comparisons between the amounts of known PFCs and EOF in the livers showed that a large proportion (approximately 70%) of the organic fluorine in both species is of unknown origin. These investigations are critical for a comprehensive assessment of the risks of these compounds to humans and other receptors.