Intracellular Porphyromonas gingivalis exploits recycling pathway to exit from infected cells

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Reduction of spatter generation using atmospheric gas in laser powder bed fusion of Ti-6Al-4V

Laser powder bed fusion (LPBF), a typical additive manufacturing (AM) process, is a promising approach that enables high-accuracy manufacturing of arbitrary structures; therefore, it has been utilized in the aerospace and medical fields. However, several unexplained phenomena significantly affect the quality of fabricated components. In particular, it has been reported that the generation of spatters adversely affects the stability of fabrication process and degrades the performance of the fabricated components. To realize high-quality components, it is essential to suppress the generation of spatters. Thus far, the suppression of spatter generation has been attempted based on the process parameters; however, this has not been adequately discussed in terms of the fabrication atmosphere. Therefore, in this study, we focused on the fabrication atmosphere and investigated spatter generation using gas with different physical properties rather than conventionally used argon. It was observed that the spatter generation during the fabrication of the Ti6Al4V alloy could be significantly suppressed by changing the atmospheric gas, even under constant LPBF process parameters. We proved that the fabrication atmosphere is an important factor to be considered, apart from the process parameters, in AM technology.Amano H., Yamaguchi Y., Ishimoto T., et al. Reduction of spatter generation using atmospheric gas in laser powder bed fusion of Ti-6Al-4V. Materials Transactions 62, 1225 (2021); https://doi.org/10.2320/matertrans.MT-M2021059

The Effect of Minimum and Maximum Air Temperatures in the Summer on Heat Stroke in Japan: A Time-Stratified Case-Crossover Study

An increase in the global surface temperature and changes in urban morphologies are associated with increased heat stress especially in urban areas. This can be one of the contributing factors underlying an increase in heat strokes. We examined the impact of summer minimum air temperatures, which often represent nighttime temperatures, as well as a maximum temperature on a heat stroke. We collected data from the records of daily ambulance transports for heat strokes and meteorological data for July and August of 2017–2019 in the Tottori Prefecture, Japan. A time-stratified case-crossover design was used to determine the association of maximum/minimum air temperatures and the incidence of heat strokes. We used a logistic regression to identify factors associated with the severity of heat strokes. A total of 1108 cases were identified with 373 (33.7%) calls originating in the home (of these, 59.8% were the age of ≥ 75). A total of 65.8% of cases under the age of 18 were related to exercise. Days with a minimum temperature ≥ 25 °C had an odds ratio (95% confidence interval) of 3.77 (2.19, 6.51) for the incidence of an exercise-related heat stroke (reference: days with a minimum temperature < 23 °C). The odds ratio for a heat stroke occurring at home or for calls for an ambulance to the home was 6.75 (4.47, 10.20). The severity of the heat stroke was associated with older age but not with air temperature. Minimum and maximum air temperatures may be associated with the incidence of heat strokes and in particular the former with non-exertional heat strokes

Spatial Characteristics of Groundwater Chemistry in Unzen, Nagasaki, Japan

Nitrate pollution in groundwater is a serious problem in Shimabara Peninsula, Nagasaki, Japan. A better understanding of the hydrogeochemical evolution of groundwater in vulnerable aquifers is important for health and environment. In this study, groundwater samples were collected at 12 residential and 57 municipal water supply wells and springs in July and August 2018. Nitrate (NO3-N) concentration at eight sampling sites (12%) exceeded Japanese drinking water standard for NO3 + NO2-N (10 mg L-1). The highest nitrate concentration was 19.9 mg L-1. Polluted groundwater is distributed in northeastern, northwestern, and southwestern areas, where land is used for intensive agriculture. Correlation analysis suggests that nitrate sources are agricultural fertilizers and livestock waste. Dominant groundwater chemistry is (Ca+Mg)-HCO3 or (Ca+Mg)-(SO4+NO3) type. Groundwater with higher nitrate concentration is of (Ca+Mg)-(SO4+NO3) type, indicating nitrate pollution affecting water chemistry. Principal component analysis extracted two important factors controlling water chemistry. The first principal component explained dissolved ions through water-rock interaction and agricultural activities. The second principal component explained cation exchange and dominant agricultural effects from fertilizers. Hierarchical cluster analysis classified groundwater into four groups. One of these is related to the dissolution of major ions. The other three represent nitrate pollution

Plasma Oxytocin Concentrations During and After Gestation in Japanese Pregnant Women Affected by Anxiety Disorder and Endometriosis

[Background] Oxytocin has a key role in mother-infant bonding, maternal care, social interaction, and stress-related psychiatric disorders. However, the factors determining oxytocin concentrations during and after pregnancy such as medical history related to nursing or parental behavior are unknown. To elucidate these, we analyzed the relationships between oxytocin concentrations during and after pregnancy, and medical history assessed in the Japan Environment and Children’s Study (JECS). [Methods] We then selected the pregnant women with a medical history of anxiety disorder and endometriosis as cases and pregnant women without medical history as controls adjusting the cohort for age and parity for a nested case-control study, after which 162 women remained for analysis. We evaluated 162 pregnant women from JECS using answers provided in a questionnaire and by measuring plasma oxytocin concentration by ELISA during the first (T1) and second (T2) trimesters of pregnancy, and after childbirth (T3). [Results] Oxytocin concentration increased in a time dependent manner, consistent with previous reports. There were weak negative correlations between oxytocin concentration at T1 and the mother’s age and height, but no correlation with other factors. The mean oxytocin concentrations of pregnant women with a history of an anxiety disorder (n = 7) and endometriosis (n = 13) were significantly lower than those of pregnant women with no such history at T2 and T3. [Conclusion] These results suggest that oxytocin concentrations during and after pregnancy were affected by a past history of anxiety disorder and endometriosis. This is the first study of the relationship between oxytocin concentration and endometriosis. To elucidate the molecular mechanisms, further study is needed

Spatiotemporal variation of nitrate concentrations in soil and groundwater of an intensely polluted agricultural area

Nitrate pollution in groundwater is a serious problem in many parts of the world. However, due to the diffuse and common spatially over-lapping character of potential several non-point pollution sources, it is often difficult to distinguish main nitrate sources responsible for the pollution. For this purpose, we present a novel methodology applied to groundwater for an intensely polluted area. Groundwater samples were collected monthly from April 2017 to March 2018 in Shimabara City, Nagasaki, Japan. Soil samples were collected seasonally at soil surface and 50 cm depth at 10 locations during the same period. Sequential extraction by water and extract agents was performed using calcium phosphate for anions and strontium chloride for cations. Mean nitrate concentration in groundwater close to a livestock waste disposal site (hereinafter called “LWDS”) was 14.2 mg L−1, which is exceeding Japanese drinking water standards (10 mg L−1). We used coprostanol concentration, which is a fecal pollution indicator, to identify pollution sources related to livestock waste. For this purpose, we measured coprostanol (5β) and cholestanol (5α) and then calculated the sterol ratio (5β/(5β + 5α)). The ratios for three groundwater sampling sites were 0.28, 0.26, and 0.10, respectively. The sterol ratios indicated no pollution (< 0.3). However, the detection of coprostanol originating from animal and human waste showed that groundwater was clearly affected by this pollution source. Nitrate levels in the soil were relatively high in samples collected close to the LWDS and coprostanol contents were affected by livestock waste. Soil and groundwater nitrate concentrations displayed a complex but strong relationship. Nitrate contents were shown to be transported downstream from source areas in both soil and groundwater

Groundwater Quality and Potential Pollution in the Southern Shimabara Peninsula, Japan

Nitrate pollution in groundwater is a severe problem in Shimabara Peninsula, Nagasaki Prefecture, Japan. Previous studies have investigated water quality characteristics in the northern part of the peninsula and shown serious effects of nitrate pollution in the groundwater. The present study aimed to investigate the groundwater quality in the southern areas of the peninsula for improved understanding of the water quality status for the entire peninsula. Groundwater samples were collected at 56 locations in Minami-Shimabara City from 28 July to 4 August 2021. The spatial distribution of water quality constituents was assessed by Piper-trilinear and Stiff diagrams for major ion concentrations. One agricultural area in the western parts exceeded Japanese recommended standards for water. According to the Piper-trilinear diagram, 44 sampling sites (78.6%) were classified as alkaline earth carbonate type, nine sites (16.1%) as alkaline earth non-carbonate type, and three sites (5.3%) as alkaline carbonate type. Stiff diagrams displayed Ca-HCO3 water type for most of the sites. Na-HCO3 and Mg-HCO3 types were found in coastal areas. Principal component analyses showed that the first component corresponded to dissolved constituents in groundwater and denitrification, the second effects of ion exchange and low nitrate pollution, and the third effects of severe nitrate pollution. Hierarchical cluster analysis was used to classify the groundwater into five groups. The first group included sites with relatively high nitrate concentration. The second group had relatively low ion concentration, distributed from center to eastern parts. The third group included intermediate ion concentration, distributed at lower altitudes along the coastal line. The fourth and fifth groups had a higher ion concentration, especially characterized by high sodium and bicarbonate concentration

The Effects of Drought Severity and Its Aftereffects on Mortality in Bangladesh

[Background] Drought has been a considerable problem for many years in northern Bangladesh. However, the health impacts of drought in this region are not well understood. [Methods] This study analyzed the impact of drought duration and severity on select causes of mortality in northern Bangladesh. Rainfall data from three meteorological stations (Rangpur, Dinajpur and Nilphamari) in northern Bangladesh were used to assess drought and non-drought periods, and the Standardized Precipitation Index was used to categorize mild, moderate, severe, and extreme drought. Mortality data from 2007 to 2017 for the three areas were collected from the Sample Vital Registration System, which is a survey of 1 million people. The generalized linear model with Poisson regression link was used to identify associations between mortality and the drought severity and 1-month preceding SPI. [Results] Only severe and extreme drought in the short-term drought periods affected mortality. Long-term drought was not associated with natural cause mortality in Rangpur and Nilphamari. In Dinajpur, mild and moderate drought was associated with circulatory- and respiratory-related mortality. [Conclusion] The impact of drought on mortality varied by region. This study improves our understanding of how droughts affect specific causes of mortality and will help policy makers to take appropriate measures against drought impacts on selected cause of mortality. Future research will be critical to reduce drought-related risks of health

Effect of a helium gas atmosphere on the mechanical properties of Ti-6Al-4V alloy built with laser powder bed fusion: A comparative study with argon gas

In metal additive manufacturing, the microstructures and associated mechanical properties of metal specimens can be controlled over a wide range. Although process parameters are considered important in the fabrication of functional parts, the effect of atmospheric gas has not been comprehensively documented. In laser powder bed fusion (LPBF), gas flow is used to eliminate fumes generated by laser irradiation. Simultaneously, the gas removes heat from the laser-irradiated part, which is exposed to high temperature. In this study, we investigated the capacity of helium as an alternative to argon, which is conventionally used as the LPBF atmosphere gas. He has a higher thermal conductivity and lower gas density than Ar, which may result in enhanced heat removal from the Ti-6Al-4V alloy during fabrication. Numerical simulations suggest a greater cooling rate under He flow. Further, the material built under He flow contained finer α' martensite grains and showed improved mechanical properties compared to those fabricated under Ar flow, despite the identical laser irradiation conditions. Thus, He gas is advantageous in LPBF for fabricating products with superior mechanical performance through microstructural refinement, and this is a result of its capacity for cooling and fume generation inhibition. Therefore, this study reveals the importance of the choice of atmospheric gas because of its effects on the characteristics of metallic specimens fabricated using LPBF.Amano H., Ishimoto T., Suganuma R., et al. Effect of a helium gas atmosphere on the mechanical properties of Ti-6Al-4V alloy built with laser powder bed fusion: A comparative study with argon gas. Additive Manufacturing, 48, 102444. https://doi.org/10.1016/j.addma.2021.102444