To investigate the antibacterial mechanism of carvacrol and thymol against Escherichia coli. The time-kill curve results showed that carvacrol and thymol at 200 mg l⁻¹ could inhibit the growth of E. ...coli. Flow cytometry and fluorescent dyes were used to explore the effect of two components on membrane permeability and membrane potential. In membrane permeability experiment, the mean fluorescence intensity of cells treated with 200 mg l⁻¹ carvacrol or thymol were lower than nonexposed cells. The ratio of red to green fluorescence intensity of DiOC₂(3) reflected the change of membrane potential. Carvacrol and thymol at 200 mg l⁻¹ caused the ratio of red/green decreasing from 0·42 of control to 0·08 and 0·07, respectively. Carvacrol and thymol had desired antimicrobial effect on E. coli. The antibacterial effects were attributed to their ability to permeabilize and depolarize the cytoplasmic membrane. This study showed the potential use of flow cytometry as a suitable method to investigate the mode of antibacterial action of essential oil components.
Compared to non-cavitating flow, cavitating flow is much complex owing to the numerical difficulties caused by cavity generation and collapse. In this paper, the cavitating flow around a NACA66 ...hydrofoil is studied numerically with particular emphasis on understanding the cavitation structures and the shedding dynamics. Large Eddy Simulation (LES) was coupled with a homogeneous cavitation model to calculate the pressure, velocity, vapor volume fraction and vorticity around the hydrofoil. The predicted cavitation shedding dynamics behavior, including the cavity growth, break-off and collapse downstream, agrees fairly well with experiment. Some fundamental issues such as the transition of a cavitating flow structure from 2D to 3D associated with cavitation-vortex interaction are discussed using the vorticity transport equation for variable density flow. A simplified one-dimensional model for the present configuration is adopted and calibrated against the LES results to better clarify the physical mechanism for the cavitation induced pressure fluctuations. The results verify the relationship between pressure fluctuations and the cavity shedding process (e.g. the variations of the flow rate and cavity volume) and demonstrate that the cavity volume acceleration is the main source of the pressure fluctuations around the cavitating hydrofoil. This research provides a better understanding of the mechanism driving the cavitation excited pressure pulsations, which will facilitate development of engineering designs to control these vibrations.
•The tip-leakage cavitating flow is simulated by LES with Cartesian cut-cell mesh.•Three types of cavitating vortical flows, including TLV, TSV and IV, are analyzed from Euler/Lagrangian ...viewpoints.•Three stages for the spatial–temporal evolution of tip-leakage cavitating flow are discussed.•The physical mechanism for cavitation-turbulence interaction is clarified.
Cavitation within a tip leakage flow remains a challenging issue in a variety of axial hydraulic machines. It is still not possible nowadays to predict cavitation occurrence in such a flow with acceptable accuracy. In the present study, we have carried out numerical simulations of a tip leakage cavitating flow, generated by a straight NACA0009 hydrofoil. We have used the LES method combined with the Schnerr–Sauer cavitation model. The numerical results agree well with experimental data. The evolution of the tip leakage cavitating flow, involving tip-leakage vortex (TLV), tip-separation vortex (TSV) and induced vortex (IV), is analyzed from Eulerian and Lagrangian viewpoints. The results show that the spatial evolution of the tip leakage cavitating flow can be divided into three stages: Stage Ⅰ, Independent development of the TLV and TSV; Stage Ⅱ, Fusion of the TLV and TSV; and Stage Ⅲ, Development of the IV and dissipation of the TLV. The Lagrangian coherent structures (LCSs) obtained from the numerical results indicate that the TLV cavitation significantly influence the local flow patterns. The vorticity transport equation was then used to further analyze the influence of the cavitation on the vortices. The results demonstrate that the stretching term dominates the TLV evolution and the dilatation term is responsible for the vorticity reduction inside the TLV cavity. The results also show how the cavitation influences the local turbulence and that the transport term in the turbulent kinetic energy equation influences the turbulence distribution near the TLV cavity.
To evaluate the dose–response relationship between cigarette smoking and pancreatic cancer and to examine the effects of temporal variables.
We analyzed data from 12 case–control studies within the ...International Pancreatic Cancer Case–Control Consortium (PanC4), including 6507 pancreatic cases and 12 890 controls. We estimated summary odds ratios (ORs) by pooling study-specific ORs using random-effects models.
Compared with never smokers, the OR was 1.2 (95% confidence interval CI 1.0–1.3) for former smokers and 2.2 (95% CI 1.7–2.8) for current cigarette smokers, with a significant increasing trend in risk with increasing number of cigarettes among current smokers (OR = 3.4 for ≥35 cigarettes per day, P for trend <0.0001). Risk increased in relation to duration of cigarette smoking up to 40 years of smoking (OR = 2.4). No trend in risk was observed for age at starting cigarette smoking, whereas risk decreased with increasing time since cigarette cessation, the OR being 0.98 after 20 years.
This uniquely large pooled analysis confirms that current cigarette smoking is associated with a twofold increased risk of pancreatic cancer and that the risk increases with the number of cigarettes smoked and duration of smoking. Risk of pancreatic cancer reaches the level of never smokers ∼20 years after quitting.
Gut mucosal microbes evolved closest to the host, developing specialized local communities. There is, however, insufficient knowledge of these communities as most studies have employed sequencing ...technologies to investigate faecal microbiota only. This work used shotgun metagenomics of mucosal biopsies to explore the microbial communities' compositions of terminal ileum and large intestine in 5 healthy individuals. Functional annotations and genome-scale metabolic modelling of selected species were then employed to identify local functional enrichments. While faecal metagenomics provided a good approximation of the average gut mucosal microbiome composition, mucosal biopsies allowed detecting the subtle variations of local microbial communities. Given their significant enrichment in the mucosal microbiota, we highlight the roles of Bacteroides species and describe the antimicrobial resistance biogeography along the intestine. We also detail which species, at which locations, are involved with the tryptophan/indole pathway, whose malfunctioning has been linked to pathologies including inflammatory bowel disease. Our study thus provides invaluable resources for investigating mechanisms connecting gut microbiota and host pathophysiology.
Pancreatitis is a known risk factor for pancreatic cancer; however, an unknown fraction of the disease is thought to be a consequence of tumor-related duct obstruction.
A pooled analysis of a history ...of pancreatitis and risk of pancreatic cancer was carried out considering the time interval between diagnoses and potential modification by covariates. Adjusted pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from 10 case–control studies (5048 cases of ductal pancreatic adenocarcinoma and 10 947 controls) taking part in the International Pancreatic Cancer Case-Control Consortium (PanC4).
The association between pancreatitis and pancreatic cancer was nearly three-fold at intervals of >2 years between diagnoses (OR: 2.71, 95% CI: 1.96–3.74) and much stronger at intervals of ≤2 years (OR: 13.56, 95% CI: 8.72–21.90) probably reflecting a combination of reverse causation and antecedent misdiagnosis of pancreas cancer as pancreatitis. The younger (<65 years) pancreatic cancer cases showed stronger associations with previous (>2 years) pancreatitis (OR: 3.91, 95% CI: 2.53–6.04) than the older (≥65 years) cases (OR: 1.68, 95% CI: 1.02–2.76; P value for interaction: 0.006).
Despite a moderately strong association between pancreatitis (diagnosed before >2 years) and pancreatic cancer, the population attributable fraction was estimated at 1.34% (95% CI: 0.612–2.07%), suggesting that a relatively small proportion of pancreatic cancer might be avoided if pancreatitis could be prevented.
Polysaccharides from Auricularia auricula (AAP) extracted in hot water and precipitated by ethanol were chemically well defined, including 42.5% total carbohydrate, 19.6% uronic acids, 15.8% sulfate ...groups, 1.7% N, and 20.3% ash. Gas chromatography analysis demonstrated that the neutral sugars were mainly composed of rhamnose, xylose, and glucose and smaller amounts of mannose, galactose, and arabinose. The present study was designed to investigate the antioxidant capacity of AAP on blood lipid metabolism and lipoprotein lipase (LPL) activity in ICR mice fed cholesterol-enriched diet (CED) for the 1st time. Furthermore, the relationship between the atherosclerotic index (AI) and LPL activity to total antioxidant capacity (TAC) was studied. Thirty-six ICR mice were randomly assigned to 3 groups (n= 12). The mice in control group (NG) received regular diet and the mice in model group (MG) received CED; these 2 groups were provided with distilled water by oral gavage. The experimental group (EG) was fed CED with oral gavage of AAP (120 mg/kg/d body weight) for an 8-wk period. After 2, 4, 6, and 8 wk, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels of the serum were determined by enzymatic methods. The results indicated that the polysaccharides significantly lowered the concentrations of serum TC and LDL-C compared with the CED control group (P < 0.05). Moreover, oral administration of polysaccharides significantly improved TAC, LPL activity, and decreased MDA level, as well as AI. These conclusions revealed the beneficial effects of AAP on the preventive actions against hypercholesterolemia.
Aim
Intussusception in adults is rare and requires surgery in most cases. While abdominal laparoscopic surgery (LS) is becoming more popular, there are few reports on the outcomes of adult ...intussusception treated with LS. This study compared the feasibility of LS vs open surgery (OS) for adult intussusception.
Method
We reviewed retrospectively the medical records of adult patients with intussusception from three tertiary hospitals between 2000 and 2016. The patients were divided into LS and OS groups, and their surgical outcomes were compared.
Results
Surgery was indicated in 71 patients with intussusception (41 LS and 30 OS). The median age of the patients was 49.0 and 51.5 years in the LS and OS groups, respectively (P = 0.930). Overall, nine (12.7%) patients had a negative laparotomy or laparoscopy with spontaneous reduction of the intussusception. Conversion to OS from LS was necessary in one patient (2.4%). The operative time and intra‐operative and postoperative complication rates were not significantly different. However, there were more serious complications such as bowel perforation and major vessel injury in the LS group. The patients in the LS group had a shorter time to first food intake and hospital stay vs patients in the OS group (4.0 vs 6.0 days, P < 0.001, and 7.0 vs 10.5 days, P < 0.001, respectively).
Conclusion
LS may be feasible for adult intussusception; there may be more severe intra‐operative complications than in OS.
Heavy alcohol drinking has been related to pancreatic cancer, but the issue is still unsolved.
To evaluate the role of alcohol consumption in relation to pancreatic cancer, we conducted a pooled ...analysis of 10 case–control studies (5585 cases and 11 827 controls) participating in the International Pancreatic Cancer Case–Control Consortium. We computed pooled odds ratios (ORs) by estimating study-specific ORs adjusted for selected covariates and pooling them using random effects models.
Compared with abstainers and occasional drinkers (<1 drink per day), we observed no association for light-to-moderate alcohol consumption (≤4 drinks per day) and pancreatic cancer risk; however, associations were above unity for higher consumption levels (OR = 1.6, 95% confidence interval 1.2–2.2 for subjects drinking ≥9 drinks per day). Results did not change substantially when we evaluated associations by tobacco smoking status, or when we excluded participants who reported a history of pancreatitis, or participants whose data were based upon proxy responses. Further, no notable differences in pooled risk estimates emerged across strata of sex, age, race, study type, and study area.
This collaborative-pooled analysis provides additional evidence for a positive association between heavy alcohol consumption and the risk of pancreatic cancer.
Chronic inflammation (CI) is a risk factor for pancreatic cancer (PC) including the most common type, ductal adenocarcinoma (PDAC), but its role and the mechanisms involved are unclear. To ...investigate the role of CI in PC, we generated genetic mouse models with pancreatic specific CI in the presence or absence of TP53. Mice were engineered to express either cyclooxygenase-2 (COX-2) or IκB kinase-2 (IKK2), and TP53
or TP53
specifically in adult pancreatic acinar cells by using a full-length pancreatic elastase promoter-driven Cre. Animals were followed for >80 weeks and pancreatic lesions were evaluated histologically and immunohistochemically. The presence of K-ras mutations was assessed by direct sequencing, locked nuclei acid (LNA)-based PCR, and immunohistochemistry. We observed that sustained COX-2/IKK2 expression caused histological abnormalities of pancreas, including increased immune cell infiltration, proliferation rate and DNA damage. A minority of animals with CI developed pre-neoplastic lesions, but cancer was not observed in any TP53
animals within 84 weeks. In contrast, all animals with CI-lacking TP53 developed various subtypes of PC, including acinar cell carcinoma, ductal adenocarcinoma, sarcomatoid carcinoma and neuroendocrine tumors, and all died within 65 weeks. No evidence of K-ras mutations was observed. Variations in the activity of the Hippo, pERK and c-Myc pathways were found in the diverse cancer subtypes. In summary, chronic inflammation is extremely inefficient at inducing PC in the presence of TP53. However, in the absence of TP53, CI leads to the development of several rare K-ras-independent forms of PC, with infrequent PDAC. This may help explain the rarity of PDAC in persons with chronic inflammatory conditions.
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