124 research outputs found
Study of Gasoline Pre-chamber combustion at Lean Operation
Regulations and other demands to enhance automobile fuel economy are growing increasingly strict to reduce CO2 as a measure to address the issues of global warming. The goal of this study was to enhance the fuel economy in high-load operation of a gasoline engine for hybrid vehicles, which is a useful means of addressing this issue. Technology for achieving lean combustion in high-load operation was studied to realize higher brake thermal efficiency by increasing the ratio of specific heat compared to theoretical air-fuel ratio (stoichiometric) EGR combustion. Issues for applying lean combustion to high-load operation include 1) the increased oxygen molarity results in increased knocking tendency compared to stoichiometric EGR combustion, and 2) increased leanness results in greater combustion variation due to the ignition delay period and the delayed second half of the combustion period. In order to solve these issues at lean operation, several combustion methods are examined on test bench. In this test study, Pre-chamber stratified combustion has an advantage of lean operation performance. Ignitability and high-speed combustion period of pre-chamber combustion was secured by setting the ignition areas inside the pre-chamber to the rich side relative to the total air-fuel ratio (A/F). NOx emissions are an issue for stratified combustion, but NOx emissions can be reduced by setting the pre-chamber A/F to approximately 23 and by making the pre-chamber volume sufficiently small compared to the main combustion chamber volume. Tests were performed using a single-cylinder engine to determine the pre-chamber volume and the diameter and number of jet nozzles. The pre-chamber volume and the diameter and number of jet nozzles were set under the restriction of dP/dθ, which is the index of combustion noise, as the target value or less. This specification realized minimum advance for the best torque (MBT) operation with an A/F of 35 at 2000 rpm, IMEP 810 kPa. The heat release characteristics of prechamber combustion shows that unlike the typical combustion pattern using strong flow, the heat release characteristics have two peaks. The first peak is the flame state wherein the jet flame has spread throughout the entire combustion chamber. This shows that the amount of heat released inside the pre-chamber enabled the flame jets from the jet nozzles to spread within the main combustion chamber. The second peak is the state wherein the unburned gas around the spread jet flames is all burning instantaneously. This combustion state results in rapid and stable combustion during the second half of combustion. This combustion characteristic realized MBT lean combustion in high-load operation. The balance between the compression ratio and the surface volume ratio (S/V) was reviewed to counter the drop in efficiency due to the increased S/V as a result of adding a pre-chamber, and this enabled MBT operation at 2000 rpm, IMEP 870 kPa, A/F 35 with an IMEP variation rate of 1.2 %, a main combustion period of 18 deg, and NOx of 30 ppm. Together with the effects of heat insulation coating inside the pre-chamber, this enhanced the brake thermal efficiency by +2 point compared to stoichiometric EGR combustion
Evaluation of adaptation to myrmecochory in etaerio-bearing plants Duchesnea chrysantha and D. indica(Rosaceae)
Duchesnea(Rosaceae)has fruits(etaerios)like strawberry(Fragaria)and is so far thought to be a bird-disseminated plant. However, its achenes possess appendages that are morphologically like elaiosomes, suggest-ing that ants would disseminate those achenes and seeds. In 1998 and 1999, we tested whether achenes(seeds) of two closely-related species D . chrysantha and D . indica, growing in Kurehayama Park and the surroundings, Toyama City, central Japan, would be removed and dispersed or not removed by ants. Four ant species(Lasius niger, Paratrechina flavipes, Pristomyrmex pungens and Tetramorium caespitum)were observed to carry the achenes to their nests. Ants frequently removed achenes of D . chrysantha but did not remove those of D . indica. Viable seeds of D . chrysantha were found at a depth from 0 to 40 cm in the soils, while those of D . indica were found only at the top layer(0to 10cm). These results suggest that the achenes of D . chrysantha may be effec-tively dispersed by ants rather than those of D . indica. We consider that D . chrysantha is amphichorous, i.e., etaerios are eaten and achenes are disseminated by birds and in the case of fruits that have not been eaten by birds, achenes drop off from the receptacle and are removed and dispersed by ants. 富山市呉羽山公園と隣接する空地に於いて, 1998 年と1999 年にヘビイチゴとヤブヘビイチゴの痩果を用いアリが運ぶかどうかの実験を行ったところ,4 種のアリ(トビイロケアリ,アメイロアリ,アミメアリ,トビイロシワアリ)が運搬した。最もよく運搬したトビイロシワアリを使用し,ヘビイチゴ群落内とヤブヘビイチゴ群落内でそれぞれどちらの痩果がよく運搬されるのかを調べたところ,ヘビ イチゴの痩果が顕著に運搬された。一方,ヤブヘビイチゴはほとんど運搬されなかった。また,痩果の付属体の有無でアリの運搬の差を調べたところ,付属体の未除去のヘビイチゴが非常によく運搬された。また,これら付属体は種子の付着部の発達したもので,多くの被子植物のエライオソームに類似していた(中西1988 の図参照)。秋に上記の場所でボーリングを行い,50 cm の土のコアーを取り,10 cm毎のサンプルに分け,それぞれのサンプルからの発芽植物を調べた。その結果,10 cm 以上の深さから出土したヘビイチゴ種子の発芽を確認した。 以上の結果から,ヘビイチゴの痩果はアリ散布であり,この植物は鳥散布に加えて,アリ散布も行う二又散布であると考えられた。
Closure of tracheoesophageal fistula with prefabricated deltopectoral flap
Tracheoesophageal fistula (TEF) is a serious complication associated with impaired quality of life. However, a successful TEF closure is difficult owing to the high incidence of recurrence. We utilized a prefabricated deltopectoral (DP) flap for closure of a TEF that occurred after an extended total thyroidectomy. Prefabrication of the inner soft tissue lining the DP flap with a split skin graft was performed prior to surgical closure of a TEF. Esophageal and tracheal mucosa were sutured to the split thickness side and full thickness side of the prefabricated DP flap, respectively. A successful closure of the fistula was achieved with this procedure. Prefabricated DP flap is a useful procedure for the surgical treatment of TEF. © 2014.Embargo Period 12 month
Study protocol of the SACURA trial: a randomized phase III trial of efficacy and safety of UFT as adjuvant chemotherapy for stage II colon cancer
BACKGROUND: Adjuvant chemotherapy for stage III colon cancer is internationally accepted as standard treatment with established efficacy, but the usefulness of adjuvant chemotherapy for stage II colon cancer remains controversial. The major Western guidelines recommend adjuvant chemotherapy for “high-risk stage II” cancer, but this is not clearly defined and the efficacy has not been confirmed. METHODS/DESIGN: SACURA trial is a multicenter randomized phase III study which aims to evaluate the superiority of 1-year adjuvant treatment with UFT to observation without any adjuvant treatment after surgery for stage II colon cancer in a large population, and to identify “high-risk factors of recurrence/death” in stage II colon cancer and predictors of efficacy and adverse events of the chemotherapy. Patients aged between 20 and 80 years with curatively resected stage II colon cancer are randomly assigned to a observation group or UFT adjuvant therapy group (UFT at 500–600 mg/day as tegafur in 2 divided doses after meals for 5 days, followed by 2-day rest. This 1-week treatment cycle is repeated for 1 year). The patients are followed up for 5 years until recurrence or death. Treatment delivery and adverse events are entered into a web-based case report form system every 3 months. The target sample size is 2,000 patients. The primary endpoint is disease-free survival, and the secondary endpoints are overall survival, recurrence-free survival, and incidence and severity of adverse events. In an additional translational study, the mRNA expression of 5-FU-related enzymes, microsatellite instability and chromosomal instability, and histopathological factors including tumor budding are assessed to evaluate correlation with recurrences, survivals and adverse events. DISCUSSION: A total of 2,024 patients were enrolled from October 2006 to July 2010. The results of this study will provide important information that help to improve the therapeutic strategy for stage II colon cancer. TRIAL REGISTRATION: ClinicalTrials.gov NCT00392899
Saliva and Plasma Reflect Metabolism Altered by Diabetes and Periodontitis
Periodontitis is an inflammatory disorder caused by disintegration of the balance between the periodontal microbiome and host response. While growing evidence suggests links between periodontitis and various metabolic disorders including type 2 diabetes (T2D), non-alcoholic liver disease, and cardiovascular disease (CVD), which often coexist in individuals with abdominal obesity, factors linking periodontal inflammation to common metabolic alterations remain to be fully elucidated. More detailed characterization of metabolomic profiles associated with multiple oral and cardiometabolic traits may provide better understanding of the complexity of oral-systemic crosstalk and its underlying mechanism. We performed comprehensive profiling of plasma and salivary metabolomes using untargeted gas chromatography/mass spectrometry to investigate multivariate covariation with clinical markers of oral and systemic health in 31 T2D patients with metabolic comorbidities and 30 control subjects. Orthogonal partial least squares (OPLS) results enabled more accurate characterization of associations among 11 oral and 25 systemic clinical outcomes, and 143 salivary and 78 plasma metabolites. In particular, metabolites that reflect cardiometabolic changes were identified in both plasma and saliva, with plasma and salivary ratios of (mannose + allose):1,5-anhydroglucitol achieving areas under the curve of 0.99 and 0.92, respectively, for T2D diagnosis. Additionally, OPLS analysis of periodontal inflamed surface area (PISA) as the numerical response variable revealed shared and unique responses of metabolomic and clinical markers to PISA between healthy and T2D groups. When combined with linear regression models, we found a significant correlation between PISA and multiple metabolites in both groups, including threonate, cadaverine and hydrocinnamate in saliva, as well as lactate and pentadecanoic acid in plasma, of which plasma lactate showed a predominant trend in the healthy group. Unique metabolites associated with PISA in the T2D group included plasma phosphate and salivary malate, while those in the healthy group included plasma gluconate and salivary adenosine. Remarkably, higher PISA was correlated with altered hepatic lipid metabolism in both groups, including higher levels of triglycerides, aspartate aminotransferase and alanine aminotransferase, leading to increased risk of cardiometabolic disease based on a score summarizing levels of CVD-related biomarkers. These findings revealed the potential utility of saliva for evaluating the risk of metabolic disorders without need for a blood test, and provide evidence that disrupted liver lipid metabolism may underlie the link between periodontitis and cardiometabolic disease.Sakanaka A., Kuboniwa M., Katakami N., et al. Saliva and Plasma Reflect Metabolism Altered by Diabetes and Periodontitis. Frontiers in Molecular Biosciences, 8, , 742002. https://doi.org/https://doi.org/10.3389/fmolb.2021.742002
Salivary metabolic signatures of carotid atherosclerosis in patients with type 2 diabetes hospitalized for treatment
Atherosclerosis is a life-threatening disease associated with morbidity and mortality in patients with type 2 diabetes (T2D). This study aimed to characterize a salivary signature of atherosclerosis based on evaluation of carotid intima-media thickness (IMT) to develop a non-invasive predictive tool for diagnosis and disease follow-up. Metabolites in saliva and plasma samples collected at admission and after treatment from 25 T2D patients hospitalized for 2 weeks to undergo medical treatment for diabetes were comprehensively profiled using metabolomic profiling with gas chromatography-mass spectrometry. Orthogonal partial least squares analysis, used to explore the relationships of IMT with clinical markers and plasma and salivary metabolites, showed that the top predictors for IMT included salivary allantoin and 1,5-anhydroglucitol (1,5-AG) at both the baseline examination at admission and after treatment. Furthermore, though treatment induced alterations in salivary levels of allantoin and 1,5-AG, it did not modify the association between IMT and these metabolites (pinteraction > 0.05), and models with these metabolites combined yielded satisfactory diagnostic accuracy for the high IMT group even after treatment (area under curve = 0.819). Collectively, this salivary metabolite combination may be useful for non-invasive identification of T2D patients with a higher atherosclerotic burden in clinical settings.Sakanaka A, Katakami N, Furuno M, Nishizawa H, Omori K, Taya N, Ishikawa A, Mayumi S, Inoue M, Tanaka Isomura E, Amano A, Shimomura I, Fukusaki E and Kuboniwa M (2022) Salivary metabolic signatures of carotid atherosclerosis in patients with type 2 diabetes hospitalized for treatment. Front. Mol. Biosci. 9:1074285. doi: 10.3389/fmolb.2022.107428
Expression of interleukin-33 is correlated with poor prognosis of patients with squamous cell carcinoma of the tongue
Objective: The aim of this study was to clarify the role of IL-33 in tumor progression. Methods: Surgical specimens from 81 patients with squamous cell carcinoma of the tongue were studied using immunohistochemistry. Primary tumor sections were analyzed for IL-33 and ST2 expression. To examine the influence of IL-33 on the microenvironment of the tumor, we determined the mast cell density (MCD) and microvessel density of the stroma. Results: Patients with high IL-33 expression had a significantly worse prognosis (p = 0.004). IL-33 expression was significantly elevated in patients with local and nodal recurrence (p = 0.014 and p = 0.019). ST2 expression was also associated with a worse prognosis (p = 0.024) and was significantly elevated in patients with nodal recurrence (p = 0.004). MCD was associated with worse prognosis (p = 0.038) and correlated significantly with IL-33 expression (r = 0.626, p < 0.001). Micovessels in the stroma were significantly increased in the high IL-33 group (p < 0.001). Conclusion: These data suggest that the IL-33/ST2 axis contributes to tumor aggressiveness and affects the tumor microenvironment. Immunohistochemical evaluation of IL-33 and ST2 is useful for identifying patients at a high risk for poor prognosis. © 2014 Elsevier Ireland Ltd. All rights reserved
Early gastric cancer detection in high-risk patients: a multicentre randomised controlled trial on the effect of second-generation narrow band imaging
Objective: Early detection of gastric cancer has been the topic of major efforts in high prevalence areas. Whether advanced imaging methods, such as second-generation narrow band imaging (2G-NBI) can improve early detection, is unknown. Design: This open-label, randomised, controlled tandem trial was conducted in 13 hospitals. Patients at increased risk for gastric cancer were randomly assigned to primary white light imaging (WLI) followed by secondary 2G-NBI (WLI group: n=2258) and primary 2G-NBI followed by secondary WLI (2G-NBI group: n=2265) performed by the same examiner. Suspected early gastric cancer (EGC) lesions in both groups were biopsied. Primary endpoint was the rate of EGC patients in the primary examination. The main secondary endpoint was the positive predictive value (PPV) for EGC in suspicious lesions detected (primary examination). Results: The overall sensitivity of primary endoscopy for the detection of EGC in high-risk patients was only 75% and should be improved. 2G-NBI did not increase EGC detection rate over conventional WLI. The impact of a slightly better PPV of 2G-NBI has to be evaluated further. Trial registration number: UMIN000014503
Assessment of Outcomes From 1-Year Surveillance After Detection of Early Gastric Cancer Among Patients at High Risk in Japan
[Importance] Single endoscopic examination often misses early gastric cancer (GC), even when both high-definition white light imaging and narrow-band imaging are used. It is unknown whether new GC can be detected approximately 1 year after intensive index endoscopic examination. [Objective] To examine whether new GC can be detected approximately 1 year after intensive index endoscopic examination using both white light and narrow-band imaging. [Design, Setting, and Participants] This case-control study was a preplanned secondary analysis of a randomized clinical trial involving 4523 patients with a high risk of GC who were enrolled between October 1, 2014, and September 22, 2017. Data were analyzed from December 26, 2019, to April 21, 2021. Participants in the clinical trial received index endoscopy to detect early GC via 2 examinations of the entire stomach using white light and narrow-band imaging. The duration of follow-up was 15 months. The secondary analysis included 107 patients with newly detected GC (case group) and 107 matched patients without newly detected GC (control group) within 15 months after index endoscopy. [Interventions] Surveillance endoscopy was scheduled between 9 and 15 months after index endoscopy. If new lesions suspected of being early GC were detected during surveillance endoscopy, biopsies were obtained to confirm the presence of cancer. [Main Outcomes and Measures] The primary end point was the rate of new GC detected within 15 months after index endoscopy. The main secondary end point was identification of risk factors associated with new GC detected within 15 months after index endoscopy. [Results] Among 4523 patients (mean [SD] age, 70.6 [7.5] years; 3527 men [78.0%]; all of Japanese ethnicity) enrolled in the clinical trial, 4472 received index endoscopy; the rate of early GC detected on index endoscopy was 3.0% (133 patients). Surveillance endoscopy was performed in 4146 of 4472 patients (92.7%) who received an index endoscopy; the rate of new GC detected within 15 months after index endoscopy was 2.6% (107 patients). Among 133 patients for whom early GC was detected during index endoscopy, 110 patients (82.7%) received surveillance endoscopy within 15 months after index endoscopy; the rate of newly detected GC was 10.9% (12 patients). For the secondary analysis of risk factors associated with newly detected GC, characteristics were well balanced between the 107 patients included in the case group vs the 107 patients included in the matched control group (mean [SD] age, 71.7 [7.2] years vs 71.8 [7.0] years; 94 men [87.9%] in each group; 82 patients [76.6%] vs 87 patients [81.3%] with a history of gastric neoplasm). Multivariate analysis revealed that the presence of open-type atrophic gastritis (odds ratio, 6.00; 95% CI, 2.25-16.01; P < .001) and early GC detection by index endoscopy (odds ratio, 4.67; 95% CI, 1.08-20.21; P = .04) were independent risk factors associated with new GC detection. [Conclusions and Relevance] In this study, the rate of new GC detected by surveillance endoscopy approximately 1 year after index endoscopy was similar to that of early GC detected by index endoscopy. These findings suggest that 1-year surveillance is warranted for patients at high risk of GC
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