Esophageal squamous cell carcinoma : opportunities for prevention

Esophageal squamous cell carcinoma (ESCC) is the predominant histological subtype of esophageal cancer, a highly fatal malignant neoplasm. Most ESCC patients are diagnosed at a late stage when tumors are unresectable or have metastasized. The median survival is less than one year, highlighting a great need for early diagnosis and preventive measures. The overall aim of the thesis is to provide a better knowledge of how ESCC can be prevented. Study I is an incidence study based on the data collected directly from 30 cancer registries in 20 countries for 1970-2015. Cross-sectional analyses of the year 2012 showed that the highest incidence rate of ESCC was in Japan (9.7/100,000 person-years). The incidence had decreased continuously in men globally but slightly increased in women from Japan, the Netherlands, New Zealand, Norway, and Switzerland. Age-period-cohort analyses revealed that birth-cohort effects were strong determinants for the incidence trends. Study II is a systematic review and meta-analysis assessing tobacco smoking cessation and risk of ESCC. We found 41 relevant studies from 15,009 publications. The random-effects model was applied to estimate pooled risk ratios (RRs) with 95% confidence intervals (CIs). Compared with current smokers, those who stopped smoking 5-9 years earlier had a decreased risk of ESCC (RR 0.59, 95% CI 0.47-0.75), and the risk reduction was stronger in those who had stopped smoking 10-20 years earlier and reached almost the level of nonsmokers in those who had stopped smoking >20 years ago (RR 0.34, 95% CI 0.25-0.47). Thus, smoking cessation seems to reduce the risk of ESCC strongly. Study III is a Swedish nationwide population-based cohort study in 2005-2015. Among 8.4 million participants, we identified 411,603 metformin users for the study who were compared with ten times as many age- and sex-matched nonusers of metformin. Hazard ratios (HRs) were estimated using multivariable cause-specific proportional hazards modeling. The ESCC incidence rate was 3.5/100,000 person-years in metformin users and 5.3/100,000 person-years in nonusers. Compared with nonusers, ever-users of metformin had an HR of 0.68 (95% CI 0.54-0.85) and new metformin users had an HR of 0.44 (95% CI 0.28-0.64). Thus, metformin use may prevent ESCC. Study IV is a Swedish nationwide case-control study in 1995-1997, including 167 ESCC cases and 820 randomly selected control participants who were all personally interviewed.A risk prediction model was developed based on the predictors: age, sex, smoking, alcohol use, education, duration of the partnership, and childhood residence. The area under the receiver operating characteristic curve was 0.81 (95% CI 0.77-0.84). With these predictors, an individual’s absolute risk of ESCC within the next five years can be predicted. In summary, this thesis indicates that ESCC remains common cancer globally, that prevention of this tumor may be possible by smoking cessation and metformin use, and those high-risk individuals can be identified by a risk prediction model, which may enable earlier tumor detection

Studying top quark decay into the polarized W-boson in the TC2 model

We study the decay mode of top quark decaying into Wb in the TC2 model where the top quark is distinguished from other fermions by participating in a strong interaction. We find that the TC2 correction to the decay width $\Gamma (t \to b W)$ is generally several percent and maximum value can reach 8% for the currently allowed parameters. The magnitude of such correction is comparable with QCD correction and larger than that of minimal supersymmetric model. Such correction might be observable in the future colliders. We also study the TC2 correction to the branching ratio of top quark decay into the polarized W bosons and find the correction is below $1$. After considering the TC2 correction, we find that our theoretical predictions about the decay branching ratio are also consistent with the experimental data.Comment: 8 pages, 4 figure

Principle and Development of Phage-Based Biosensors

Detection and identification of pathogenic bacteria is important in the field of public health, medicine, food safety, environmental monitoring and security. Worldwide, the common cause of mortality and morbidity is bacterial infection often due to misdiagnosis or delay in diagnosis. Existing bacterial detection methods rely on conventional culture or microscopic techniques and molecular methods that often time consuming, laborious and expensive, or need trained users. In recent years, biosensor remained an interesting topic for bacterial detection and many biosensors involving different bio-probes have been reported. Compared to antibodies, nucleic acids and enzymes etc., based biosensors, bacteriophages can be cheaply produced and are relatively much stable to elevated temperature, extreme pH, and diverse ionic strength. Therefore, there is an urgent need for phage-based biosensor for bacterial pathogen detection. Furthermore, bearing high affinity and specificity, bacteriophages are perfect bio-recognition probes in biosensor development for bacterial detection. In this regard, active and oriented phages immobilization is the key step toward phage-based biosensor development. This chapter compares different bacterial detection techniques, and introduces the basic of biosensor and different bio-probes involved in biosensor development. Further we highlight the involvement and importance of phages in biosensor and finally we briefed different phage immobilization approaches used in development of phage-based biosensors

Applications of Phage-Based Biosensors in the Diagnosis of Infectious Diseases, Food Safety, and Environmental Monitoring

Environmental pollution and food safety are becoming serious concerns to human health in developing countries. To combat such issues, researchers have developed different approaches for on-spot detection and screening of infectious disease, caused by pathogens and toxins in food and water samples. One such approach is the development of phage- and phage-component-based sensors that are highly specific, sensitive, rapid, efficient, cheap, and portable analyte screening platforms. Such sensors overcome the limitations of conventional screening approaches. This chapter highlights different food and environmental contaminations and represents the potential of phage-based biosensor for bacterial detection. It summarizes different applications of phage-based sensors in the fields of food safety and environmental monitoring and highlights current challenges and perspective. In general, this chapter brings together the technologies related to phage-based sensors and food and environmental safety, by compiling the efforts of engineers and scientists from multidisciplinary areas

EFFECT OF DROUGHT STRESS ON PHYSIOLOGICAL GROWTH PARAMETERS OF TOMATO INBRED LINES AT GERMINATION STAGE

This study was carried out to investigate the effect of water stress condition in growth parameters of 35 tomato inbred lines. Those inbred lines are collected from different countries and they were screened with osmotic concentration of 12.5 % polyethylene glycol 6000 while their respective control treatments were treated using distilled water for twelve days at germination stage. The relative percentages of shoot length, root length, shoot weight; root weight and relative germination rate were computed to determine the effect of water stress on the growth parameters of the inbred lines. According the experiment’s result, drought tolerant inbred lines have longer root length and higher root weight than the susceptible inbred lines. Shoot length and shoot weight was not much affected by the drought situation at the germination stage. The most drought tolerant inbred lines have the highest relative germination rate and the drought susceptible inbred lines have a lower relative germination rate. The highest germination percentage was recorded at control treatments than in the PEG treatments

Oxidative damage from repeated tissue isolation for subculturing causes degeneration in Volvariella volvacea

The fungal fruiting body is the organized mycelium. Tissue isolation and mycelium succession are common methods of fungal species purification and rejuvenation in the production of edible mushrooms. However, repeated succession increases strain degeneration. In this study, we examined the effect of repeated tissue isolation from Volvariella volvacea fruitbodies on the occurrence of degeneration. The results showed that less than four times in succession improved production capacity, however, after 12 successions, the traits indicating strain degeneration were apparent. For instance, the density of aerophytic hyphae, hyphal growth rate and hyphal biomass were gradually reduced, while the hyphae branching was increased. Also, other degenerative traits such as prolonged production cycles and decreased biological efficiency became evident. In particular, after 19 successions, the strain degeneration became so severe no fruiting bodies were produces anymore. Meanwhile, with the increase in successions, the antioxidant enzyme activity decreased, reactive oxygen species (ROS) increased, the number of nuclei decreased, and the mitochondrial membrane potential decreased along with morphological changes in the mitochondria. This study showed that repeated tissue isolation increased oxidative damage in the succession strain due to the accumulation of ROS, causing cellular senescence, in turn, degeneration in V. volvacea strain

Xiaolangdi 貯水池の水中の微量物質に関する研究

As one of the strategic projects, Xiaolangdi Dam Project has many functions, including flood control, water supply for municipal and irrigation, etc. And water quality of Xiaolangdi reservoir will directly affects industrial and agricultural production and health of residents in the reservoir area and downstream areas. So the fate of toxic heavy metals in water of the Xiaolangdi is highly concerned. Samples of surface water from Mingzhudao and Zhangling in the Xiaolangdi reservoir，were analyzed to assess the water quality. Nine trace elements, including Hg, Se, Cd，Cr, Cu, Zn, Fe, Mn and F were determined. Concentrations of As, Cr, Cu, and Zn were lower than the detection limit in the Xiaolangdi water. The mean concentration of mercury in the studied areas was higher than the III class of Chinese surface water quality standards limit, while other elements were lower than the limit. And the concentration of mercury increases as water depth increases，it may be due to sedimentation of mercury micro-organisms or biogeochemical cycle of mercury. Se and Cd in the Xiaolangdi Reservoir were distributed evenly, and their contents changed little with water depth.特集 : 「資源、新エネルギー、環境、防災研究国際セミナー

Preliminary Study on Environmental Geochemistry in the Paleo-sediment of the Yellow River of Wuzhi, China

This work studied trace elements in the paleo-sediment of the Yellow River of Wuzhi, Jiaozuo, Henan Province, using the flame atomic absorption spectrometry and atomic fluorescence spectrometry to analyze the concentration of trace elements (Cu、Ni、Mn、Zn、Pb、Cr、Fe、As). The concentrations of the eight trace elements in the paleo-sediment of the Yellow River ranged between 6.42 and 28.35 mg·kg-1 (mean 15.09 mg·kg-1), 13.69 and 39.24 mg·kg-1 (21.31 mg·kg-1), 158.8 and 338.65 mg·kg-1 (219.56 mg·kg-1), 178.25 and 309.75 mg·kg-1 (239.49 mg·kg-1), 14.16 and 27.19 mg·kg-1 (20.22 mg·kg-1), 27.25 and 67.71 mg·kg-1 (37.84 mg·kg-1), 17830 and 34080 mg·kg-1 (25942 mg·kg-1) and 26.315 and 532.01 mg·kg-1 (141.71 mg·kg-1), respectively. The results showed that the impact of human activities is one of the main factors, especially the destruction of natural vegetation of the middle reaches of Loess Plateau in the Qin and Han Dynasties and the development of industry and agriculture.特集 : 「資源、新エネルギー、環境、防災研究国際セミナー