Despite many studies on seafloor hydrothermal systems conducted to date, the generation mechanism of seafloor massive sulfide (SMS) deposits is not yet fully understood. To elucidate this mechanism, ...this study clarifies the three‐dimensional regional temperature distribution and fluid flow of a seafloor hydrothermal system of the Iheya North Knoll, middle Okinawa Trough. Lateral flow and boiling of hydrothermal fluids below a caprock were the main features found by the simulation. A caprock formation generated by anhydrite precipitation and hydrothermal alteration is the most plausible cause of these features, because caprocks can increase the temperature and induce boiling of fluids by preventing seawater inflow. Such a formation also gradually makes the top of the conduit less permeable; thus, lateral flow occurs. Consequently, vapor‐rich hydrothermal fluids poor in metals are discharged from vents as white smokers, whereas liquid‐dominated hydrothermal fluids rich in metals flow laterally below the caprocks, forming subseafloor SMS deposits.
Plain Language Summary
In seafloor hydrothermal systems, the seawater heated by magma circulates under the seafloor and forms seafloor massive sulfide (SMS) deposits. Recently, SMS deposits have attracted interest as a new metal resource, the generation mechanism and model of which must be established for accurate resource exploration. However, the mechanism is not yet fully understood. To address this problem, we applied a hydrothermal flow simulation and clarified the temperature distribution and fluid flow in the Iheya North Knoll, southwestern Japan. The result revealed that lateral flow and boiling of hydrothermal fluids occur below the seafloor. A low permeability caprock formation generated by anhydrite and clay mineral development is the most plausible cause of these occurrences, because a caprock can increase the temperature and induce boiling of fluids by suppressing the seawater inflow. This formation also makes fluid outlets less permeable, thus induces lateral flow. Consequently, vapor‐rich hydrothermal fluids poor in metals are discharged from vents, while liquid‐dominated hydrothermal fluids rich in metals flow laterally below the caprocks, forming subseafloor SMS deposits.
Key Points
Numerical simulation of multiphase fluid flow revealed regional temperature, fluid‐flow patterns, and physical property distributions
Integration of results with geologic interpretations provided a plausible generation mechanism of seafloor massive sulfide deposits
Formation of caprocks below the seafloor induces boiling and lateral flow of hydrothermal fluid and, consequently, the deposit generation
Although seafloor massive sulfide (SMS) deposits are crucially important metal resources that contain high‐grade metals such as copper, lead, and zinc, their internal structures and generation ...mechanisms remain unclear. This study obtained detailed near‐seafloor images of electrical resistivity in a hydrothermal field off Okinawa, southwestern Japan, using deep‐towed marine electrical resistivity tomography. The image clarified a semi‐layered resistivity structure, interpreted as SMS deposits exposed on the seafloor, and another deep‐seated SMS layer at about 40‐m depth below the seafloor. The images reinforce our inference of a new mechanism of SMS evolution: Upwelling hydrothermal fluid is trapped under less‐permeable cap rock. The deeper embedded SMS accumulates there. Then hydrothermal fluids expelled on the seafloor form exposed SMS deposits.
Plain Language Summary
Hydrothermal circulation of seawater through the permeable ocean crust engenders formation of seafloor massive sulfide (SMS) deposits, which present high potential for metal mining. Geophysical surveys using modes such as electrical and electromagnetic methods have revealed that SMS deposits exhibit lower resistivity than the surrounding host rock. However, because detailed geophysical images of internal structures of SMS deposits are lacking, the spatial distribution of SMS deposits and the evolutionary processes of SMS deposits remain unclear. For this study, we applied a deep‐towed marine electrical resistivity tomography (ERT) system to capture detailed images of electrical resistivity structures of SMS deposits in the Iheya North hydrothermal field, Okinawa Trough, southwestern Japan. An optimal sub‐seafloor resistivity section reveals a semi‐layered structure consisting of double low‐resistivity SMS layers: exposed and deep‐seated ones. Between the SMS layers, a cap rock layer is recognized as a moderately resistive zone. This detailed structure offers an explanation of how the SMS deposits accumulate: Hydrothermal fluids upwelling from the deep crust are trapped by less‐permeable cap rock, which results in the precipitation and accumulation of SMS deposits below the cap rock. Then fluids passing through the cap rock to the seafloor produce SMS deposits on the seafloor.
Key Points
Deep‐towed marine electrical resistivity tomography revealed massive sulfide deposits on the seafloor as low‐resistivity zones
Low‐resistivity zones are semi‐layered with deposits exposed on the seafloor and other deposits at 40‐m depth below the seafloor
Detailed near‐seafloor images of electrical resistivity offer an explanation of how the SMS deposits accumulate
Inflammation-based prognostic scores including the Glasgow Prognostic Score (GPS), neutrophil to lymphocyte ratio (NLR), and Prognostic Nutritional Index (PNI) are associated with survival in ...patients with hepatocellular carcinoma (HCC). The aim of this study was to investigate the prognostic value of these inflammation-based prognostic scores in patients with HCC.
In total, 150 patients with newly diagnosed HCC were prospectively evaluated. Patients were divided according to the GPS, modified GPS, NLR, platelet to lymphocyte ratio (PLR), Prognostic Index (PI), and PNI. The area under the receiver operating characteristics curve (AUC) was calculated to compare the predictive ability of each of the scoring systems. A univariate and multivariate analysis were performed to identify the clinicopathological variables associated with overall survival.
The GPS consistently had a higher AUC value at 6 months (0.768), 12 months (0.787), and 24 months (0.758) in comparison with other inflammation-based prognostic scores. A multivariate analysis showed that the GPS was independently associated with overall survival.
This study demonstrates that the GPS, an inflammation-based prognostic score, is an independent marker of poor prognosis in patients with HCC and is superior to the other inflammation-based prognostic scores in terms of prognostic ability.
Epigenetic gene regulation linked to oncogenic pathways is an important focus of cancer research. KDM3A, a histone H3 lysine 9 (H3K9) demethylase, is known to have a pro-tumorigenic function. Here, ...we showed that KDM3A contributes to liver tumor formation through the phosphatidylinositol 3-kinase (PI3K) pathway, which is often activated in hepatocellular carcinoma. Loss of Kdm3a attenuated tumor formation in Pik3ca transgenic (Tg) mouse livers. Transcriptome analysis of pre-cancerous liver tissues revealed that the expression of activator protein 1 (AP-1) target genes was induced by PI3K activation, but blunted upon Kdm3a ablation. Particularly, the expression of Cd44, a liver cancer stem marker, was regulated by AP-1 in a Kdm3a-dependent manner. We identified Cd44-positive hepatocytes with epithelial-mesenchymal transition-related expression profiles in the Pik3ca Tg liver and confirmed their in vivo tumorigenic capacity. Notably, the number and tumor-initiating capacity of Cd44-positive hepatocytes were governed by Kdm3a. As a mechanism in Kdm3a-dependent AP-1 transcription, Kdm3a recruited c-Jun to the AP-1 binding sites of Cd44, Mmp7 and Pdgfrb without affecting c-Jun expression. Moreover, Brg1, a component of the SWI/SNF chromatin remodeling complex, interacted with c-Jun in a Kdm3a-dependent manner and was bound to the AP-1 binding site of these genes. Finally, KDM3A and c-JUN were co-expressed in 33% of human premalignant lesions with PI3K activation. Our data suggest a critical role for KDM3A in the PI3K/AP-1 oncogenic axis and propose a novel strategy for inhibition of KDM3A against liver tumor development under PI3K pathway activation.
Endoscopic submucosal dissection (ESD) provides a high en bloc resection rate with less invasiveness than surgical resection for large or scarring gastrointestinal neoplasms. However, detailed ...outcomes in colorectal ESD are still lacking. The aim of our study was to elucidate short- and long-term outcomes of colorectal ESD.
310 consecutive colorectal epithelial neoplasms (146 adenomas, 164 carcinomas), in 290 patients, which fulfilled our indication criteria and were treated with ESD between July 2000 and December 2008 were studied. ESD was done by three skilled endoscopists. As short-term outcomes, rates of en bloc resection, en bloc plus R0 resection, and major complications were analyzed. As long-term outcomes, disease-free and overall survival were assessed in 224 patients.
Rates of en bloc resection and en bloc plus R0 resection were 90.3 % and 74.5 %, respectively. Eight patients underwent additional colectomy due to histopathologically proven possible node-positive cancer. Intraoperative perforations occurred with 14 lesions (4.5 %), which were treated successfully only by endoscopic clipping. Emergent surgery was needed for one case of postoperative perforation. Blood transfusion due to intraoperative massive bleeding was required in 1 case (0.3 %). Postoperative bleeding occurred with four lesions (1.3 %), and was endoscopically managed without blood transfusion. Local recurrence was detected in 4 lesions (4/202 patients, 2.0 %); resection had been piecemeal in all 4. During a median follow-up of 38.7 months (range 12.8 - 104.2), the 3- and 5-year overall/disease-specific survivals were 97.1/100 % and 95.3/100 %, respectively.
Colorectal ESD showed favorable long-term outcomes. It may largely replace colectomy for node-negative colorectal epithelial neoplasia.
Summary
The present study aimed to develop and validate a model for predicting the need for emergency front‐of neck airway (eFONA) procedures among trauma patients. This was a multicentre ...retrospective cohort study using data from the Japan Trauma Data Bank between January 2004 and December 2017. Only adult trauma patients were included. The cohort was divided into development and validation cohorts. A simple scoring system was developed to predict the necessity for emergency front‐of neck airway procedures in the development cohort using a logistic regression model. The external validity and diagnostic ability of the scoring system was assessed in the validation cohort. In total, 198,182 out of 294,274 patients were included; emergency front‐of‐neck airway occurred in 467 patients (0.24%) they were divided into development (n = 100,120 with 0.22% undergoing emergency front‐of neck airway) and validation (n = 98,062 with 0.25% undergoing emergency front‐of neck airway) cohorts. The ‘eFONA’ prediction scoring system was developed in the development cohort, with a score of +1 for each of the following: Eye opening (no eye opening in response to any stimuli); Fall from height or motor bike; Oral–maxillofacial injury; Neck tracheal injury; and Airway management by paramedics. In the validation cohort, the C‐statistic of the scoring system was 0.820. Setting the cut‐off value at one for rule‐out, the sensitivity and negative likelihood ratios were 0.86 and 0.22, respectively. Setting the cut‐off value at two for rule‐in, the specificity and positive likelihood ratios were 0.91 and 6.6, respectively. The present scoring system may assist in predicting the need for emergency front‐of neck airway procedures among the general trauma population.
As a promising candidate of optical home network, a novel Gigabit Ethernet prepared by inexpensive partially fluorinated polymer-based graded-index plastic optical fiber (GI POF) was proposed. Poly ...(2,2,2-trifluoroethyl methacrylate) (P3FMA) was selected as a base material for the GI POF because of its high transparency, low material dispersion, and low cost. The transmission characteristics were investigated, and it was clarified that the newly developed GI POF has low-loss (71 dB/km at 650 nm), high humidity stability, and high-bandwidth (4.86 GHz for 50-m transmission) property. Moreover, 1.25-Gbps data transmission over 50 m was demonstrated by P3FMA-based GI POF.
Coral–algal symbioses are essential for the survival of corals. Algal endosymbionts, specifically the dinoflagellate genus
Symbiodinium
, are divided into several genetic clades. The composition of
...Symbiodinium
within corals plays an important role in the tolerance and/or sensitivity of host corals to local environments, due to individual
Symbiodinium
-specific physiological characteristics. While the majority of gamete-spawning corals acquire
Symbiodinium
from the surrounding environment, little is known about whether corals specifically select or randomly acquire
Symbiodinium
from the environmental population. In the present study, we compared the
Symbiodinium
clade composition of newly recruited
Acropora
corals with that of the environmental pool (water column, sediments, and adult colonies). More than 90 % of recruits harbored clades A and/or D until 6 months after settlement, despite the
Symbiodinium
environmental pool being mainly composed of clade C (mainly ITS1 type C2), and to a lesser extent clades A and D. In addition, the environmentally dominant type C2
Symbiodinium
was not detected in
Acropora
recruits, while a few recruits harbored ITS1 types C1 or C15. Therefore, the clade composition of recruits may not reflect the abundance/density of
Symbiodinium
populations in the environment. Some members of clades A and D are known to exhibit tolerance to a wide range of environments. ITS1 type C1 also exhibits greater tolerance to thermal stress compared to ITS1 type C2. These tolerance characteristics of certain
Symbiodinium
may be vital for the initial survival of
Acropora
recruits, even if these
Symbiodinium
are rare in the environment.
Transgenic mice expressing HCV core protein develop hepatic steatosis and hepatocellular carcinoma (HCC), but the mechanism underlying this process remains unclear. Because PPARα is a central ...regulator of triglyceride homeostasis and mediates hepatocarcinogenesis in rodents, we determined whether PPARα contributes to HCV core protein--induced diseases. We generated PPARα-homozygous, -heterozygous, and -null mice with liver-specific transgenic expression of the core protein gene (Ppara+/+:HCVcpTg, Ppara+/-:HCVcpTg, and Ppara-/-:HCVcpTg mice. Severe steatosis was unexpectedly observed only in Ppara+/+:HCVcpTg mice, which resulted from enhanced fatty acid uptake and decreased mitochondrial β-oxidation due to breakdown of mitochondrial outer membranes. Interestingly, HCC developed in approximately 35% of 24-month-old Ppara+/+: HCVcpTg mice, but tumors were not observed in the other genotypes. These phenomena were found to be closely associated with sustained PPARα activation. In Ppara+/-:HCVcpTg mice, PPARα activation and the related changes did not occur despite the presence of a functional Ppara allele. However, long-term treatment of these mice with clofibrate, a PPARα activator, induced HCC with mitochondrial abnormalities and hepatic steatosis. Thus, our results indicate that persistent activation of PPARα is essential for the pathogenesis of hepatic steatosis and HCC induced by HCV infection.
Despite numerous lines of epidemiologic evidence connecting HCV infection and the development of hepatocellular carcinoma (HCC), it remains controversial whether HCV itself plays a direct role or an ...indirect role in the pathogenesis of HCC. Through the use of transgenic mice, it has become evident that the core protein of HCV has oncogenic potential. HCV is directly involved in hepatocarcinogenesis, albeit other factors such as inflammation and environmental factors might also play a role. The direct involvement of HCV in hepatocarcinogenesis would be achieved via 2 pathways. In one pathway, the core protein acts on the function of mitochondria, leading to the overproduction of oxidative stress, which yields genetic aberrations in cell growth-related genes. The other pathway involves the modulation of cellular gene expressions and intracellular signal transductions, such as mitogen-activated protein kinase pathway, which results in the activation of transcription factors and cell cycle machineries. The combination of these alterations would be hypothesized to provoke the development of HCC in HCV infection. This would be a mechanism for HCC development in HCV infection that is distinct from those for other cancers. The presence of the HCV core protein, to which an oncogenic potential is ascribed, might allow some of the multiple steps to be bypassed in hepatocarcinogenesis. Therefore, unlike in other cancers, HCV infection can elicit HCC in the absence of a complete set of genetic aberrations. Such a scenario, "non-Vogelstein type" carcinogenesis, may explain the unusually high incidence and multicentric nature of HCC development in HCV infection.
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