Longitudinal evaluation of aflatoxin exposure in two cohorts in south-western Uganda

Aflatoxins (AF) are a group of mycotoxins. AF exposure causes acute and chronic adverse health effects such as aflatoxicosis and hepatocellular carcinoma in human populations, especially in the developing world. In this study, AF exposure was evaluated using archived serum samples from human immunodeficiency virus (HIV)-seronegative participants from two cohort studies in south-western Uganda. AFB1-lysine (AFB-Lys) adduct levels were determined via HPLC fluorescence in a total of 713 serum samples from the General Population Cohort (GPC), covering eight time periods between 1989 and 2010. Overall, 90% (642/713) of the samples were positive for AFB-Lys and the median level was 1.58 pg mg(-1) albumin (range = 0.40-168 pg mg(-1) albumin). AFB-Lys adduct levels were also measured in a total of 374 serum samples from the Rakai Community Cohort Study (RCCS), across four time periods between 1999 and 2003. The averaged detection rate was 92.5% (346/374) and the median level was 1.18 pg mg(-1) albumin (range = 0.40-122.5 pg mg(-1) albumin). In the GPC study there were no statistically significant differences between demographic parameters, such as age, sex and level of education, and levels of serum AFB-Lys adduct. In the RCCS study, longitudinal analysis using generalised estimating equations revealed significant differences between the adduct levels and residential areas (p = 0.05) and occupations (p = 0.02). This study indicates that AF exposure in people in two populations in south-western Uganda is persistent and has not significantly changed over time. Data from one study, but not the other, indicated that agriculture workers and rural area residents had more AF exposure than those non-agricultural workers and non-rural area residents. These results suggest the need for further study of AF-induced human adverse health effects, especially the predominant diseases in the region

Durability tests of ball valve prototype with flowmeter operation

The results of the investigation of the prototypical ball valve are presented in this article. The innovation of the tested valve is a ball with a built-in measuring orifice. The valve has been subjected to durability tests. Leakage under three temperatures: ambient, -30°C and +100°C was analyzed. Sealing elements of the valve were tested for roughness and deviation of shape before and after the cycles of operation. Ball valve operation means cycles of open/close. It was planned to perform 1000 cycles at each temperature condition accordingly. Tests of the valve were performed under gas pressure equal to 10 MPa. The research was carried out under the Operational Program “Intelligent Development” (POIR 01.01.01-00-0013 / 15 “Development of devices for measurement of media flow on industrial trunk-lines”

Durability Tests of Ball Valve Prototype with Flowmeter Operation

The results of the investigation of the prototypical ball valve are presented in this article. The innovation of the tested valve is a ball with a built-in measuring orifice. The valve has been subjected to durability tests. Leakage under three temperatures: ambient, -30°C and +100°C was analyzed. Sealing elements of the valve were tested for roughness and deviation of shape before and after the cycles of operation. Ball valve operation means cycles of open/close. It was planned to perform 1000 cycles at each temperature condition accordingly. Tests of the valve were performed under gas pressure equal to 10 MPa. The research was carried out under the Operational Program “Intelligent Development” (POIR 01.01.01-00-0013 / 15 “Development of devices for measurement of media flow on industrial trunk-lines”

Crankshaft seals with reduced frictional resistance

W artykule omówiona została współpraca elastomerowego pierścienia uszczelniającego z wałem pod kątem zużycia i strat na pokonanie sił tarcia, konstrukcja klasycznego uszczelnienia oraz uszczelnienia o obniżonym oporze ruchu. Ponieważ układ warga uszczelnienia-wał to specyficzna para cierna, skoncentrowano się na lokalnych warunkach styku w skali mikro jako parametrze decydującym o globalnych oporach ruchu w skali makro. Ponieważ wystąpienie przedwczesnej awarii uszczelnienia mimo niedużych kosztów samego elementu generuje poważne koszty naprawy oraz przestój taboru transportowego problem trwałości i niezawodności pracy opisywanego typu uszczelnień pozostaje wciąż aktualny.The article discusses the cooperation of the elastomeric sealing ring with the shaft in terms of wear and losses to over-come friction forces, the construction of a classic seal and a seal with reduced resistance to movement. Because the lip-shaft system is a specific friction pair, the focus has been on local micro contact conditions as a parameter that determines global motion resistances on a macro scale. Since the occurrence of premature sealing failure in spite of small costs of the element itself generates serious costs of repair and downtime of the transport fleet, the problem of durability and reliability of the described type of seals remains valid

Crankshaft seals with reduced frictional resistance

W artykule omówiona została współpraca elastomerowego pierścienia uszczelniającego z wałem pod kątem zużycia i strat na pokonanie sił tarcia, konstrukcja klasycznego uszczelnienia oraz uszczelnienia o obniżonym oporze ruchu. Ponieważ układ warga uszczelnienia-wał to specyficzna para cierna, skoncentrowano się na lokalnych warunkach styku w skali mikro jako parametrze decydującym o globalnych oporach ruchu w skali makro. Ponieważ wystąpienie przedwczesnej awarii uszczelnienia mimo niedużych kosztów samego elementu generuje poważne koszty naprawy oraz przestój taboru transportowego problem trwałości i niezawodności pracy opisywanego typu uszczelnień pozostaje wciąż aktualny.The article discusses the cooperation of the elastomeric sealing ring with the shaft in terms of wear and losses to over-come friction forces, the construction of a classic seal and a seal with reduced resistance to movement. Because the lip-shaft system is a specific friction pair, the focus has been on local micro contact conditions as a parameter that determines global motion resistances on a macro scale. Since the occurrence of premature sealing failure in spite of small costs of the element itself generates serious costs of repair and downtime of the transport fleet, the problem of durability and reliability of the described type of seals remains valid

Techniques of Preparing Plant Material for Chromatographic Separation and Analysis

This paper discusses preparation techniques of samples of plant material for chromatographic analysis. Individual steps of the procedures used in sample preparation, including sample collection from the environment or from tissue cultures, drying, comminution, homogenization, leaching, extraction, distillation and condensation, analyte enrichment, and obtaining the final extracts for chromatographic analysis are discussed. The techniques most often used for isolation of analytes from homogenized plant material, i.e., Soxhlet extraction, ultrasonic solvent extraction (sonication), accelerated solvent extraction, microwave-assisted extraction, supercritical-fluid extraction, steam distillation, as well as membrane processes are emphasized. Sorptive methods of sample enrichment and removal of interferences, i.e., solid-phase extraction, and solid-phase micro-extraction are also discussed

Cortisol awakening response in patients with psychosis: systematic review and meta-analysis

The cortisol awakening response (CAR), defined as the increase in cortisol release in response to waking up, shows associations with social and environmental risk factors of schizophrenia and has been studied as a potential biomarker in schizophrenia. We report a systematic review and meta-analysis of 11 studies and 879 participants focusing on the CAR of patients with schizophrenia, first-episode psychosis, and at-risk mental states. Random-effects meta-analysis showed that CAR is attenuated in patients with psychosis compared to healthy controls (g = −0.426, 95% CI −0.585 to −0.267, p < 0.001, 11 between-group comparisons, n = 879). Subgroup analysis showed flattened CAR in patients with schizophrenia (g = −0.556, 95% CI −1.069 to −0.044, p < 0.05, 2 between-group comparisons, n = 114) and first-episode psychosis (g = −0.544, 95% CI −0.731 to −0.358, p < 0.001, 6 between-group comparisons, n = 505), but not in individuals with at-risk mental states. These distinctive alterations of hypothalamic-pituitary-adrenal axis function may have important implications for CAR as a marker for transition risk. However, the lack of objective verification of sampling adherence in these studies may limit the interpretation of the results

Kolumnowa chromatografia cieczowa w rozdzielaniu i analizie peptydów i białek

Szybka ekspansja zastosowań peptydów i białek w biochemii i w medycynie, stymuluje ogromny wzrost zainteresowania metodami rozdzielania peptydów. Elektroforeza żelowa i kapilarna to najczęściej dotychczas wykorzystywane metody rozdzielania peptydów i białek, w celach identyfikacyjnych i analitycznych. Metody te nie są jednak przydatne do otrzymywania użytkowych ilości tych substancji. Obecnie HPLC jest najistotniejszą metodą oczyszczania i otrzymywania peptydów i białek. Ponadto techniki HPLC znajdują coraz większe zastosowanie w rozwijającej się proteomice. W pracy dokonano przeglądu najważniejszych technik chromatografii cieczowej, metod oraz procedur stosowanych do rozdzielania peptydów i białek jak również obecnych trendów w tym obszarze