Genotoxic biomonitoring of agricultural workers exposed to pesticides in the north of Sinaloa State, Mexico

Genotoxic damage was evaluated in 70 agricultural workers, 25 women and 45 men, exposed to pesticides in Las Grullas, Ahome, Sinaloa, Mexico, with an average of 7 years of exposure. The effect was detected through the sister chromatid exchanges (SCE) in lymphocytes of peripheral blood and micronuclei (MN) and other nuclear anomalies (NA) in buccal exfoliated cells. Also, the influence on cellular proliferation kinetics (CPK) was studied by means of the replication index (RI) and the cytotoxic effect was examined with the mitotic index (MI). The non-exposed group consisted of 70 other persons, 21 women and 47 men from the city of Los Mochis, Sinaloa, Mexico. Significant differences between the exposed and the non-exposed groups were observed in SCE, CPK, MI, MN and NA. Analysis of variance revealed that age, gender, smoking and alcohol consumption did not have a significant effect on genetic damage. However, there was a correlation between exposure time to pesticides and SCE frequency. These results could have been due to the exposure of workers to pesticides containing different chemical compounds. This study afforded valuable data to estimate the possible risk to health associated with pesticide exposure.     

基于升流式厌氧污泥床反应器的微生物燃料电池的研究

构建了一种基于升流式厌氧污泥床反应器（UASB）的微生物燃料电池（MFCs）,利用UASB高效去除COD能力及连续进样方式,获得稳定电能输出。考察了水力停留时间、进液方式、电极材料、离子交换膜种类、溶液离子强度等因素对于MFCs性能的影响。实验结果表明：在水力停留时间6h、连续进液、高纯石墨板电极以及均相阳离子交换膜条件下,连续运行3个月,放电功率稳定在145mW／m^2,开路电压0．78V,放电电流最高可达321mA／m^2。     

Octanoic acid confers to royal jelly varroa-repellent properties

The mite Varroa destructor Anderson & Trueman is a parasite of the honeybee Apis mellifera L. and represents a major threat for apiculture in the Western world. Reproduction takes place only inside bee brood cells that are invaded just before sealing; drone cells are preferred over worker cells, whereas queen cells are not normally invaded. Lower incidence of mites in queen cells is at least partly due to the deterrent activity of royal jelly. In this study, the repellent properties of royal jelly were investigated using a lab bioassay. Chemical analysis showed that octanoic acid is a major volatile component of royal jelly; by contrast, the concentration is much lower in drone and worker larval food. Bioassays, carried out under lab conditions, demonstrated that octanoic acid is repellent to the mite. Field studies in bee colonies confirmed that the compound may interfere with the process of cell invasion by the mite.     

Prevalence and trends of distracted driving in Canada

Introduction: This study evaluates prevalence and trends in distracted driving in Canada based on multiple indicators collected from the Road Safety Monitor (RSM) and Canada’s National Fatality Database maintained by the Traffic Injury Research Foundation (TIRF). Method: Data from the RSM on self-reported distracted driving behaviors were analyzed using multivariate techniques including logistic regression analysis in various years spanning from 2004 to 2019. Data from TIRF’s National Fatality Database from 2000 to 2016 were also analyzed using piecewise regression analysis to evaluate trends and prevalence of driver distraction. Results: Significantly more Canadians reported talking on their phone hands-free or handheld phone while driving in 2019 compared to 2010. There was a 102% increase in the percentage that reported texting while driving in 2019 (9.7%) compared to 2010 (4.8%). For every 10-year increase in age, drivers were 44% less likely to text, 38% less likely to use a handheld phone, and 28% less likely to use a hands-free phone. Males were 62% more likely to use a handheld phone and 50% more likely to use a hands-free phone than females. Findings related to drivers’ perceived danger of distracted driving and attitudes are also presented. Although the number of distraction-related fatalities has not increased substantially from 2000 to 2016, the percentage of all fatalities where distraction was a contributing factor has increased. Unlike drinking drivers, distracted drivers more often kill other road users in crashes than kill themselves. Conclusions: In conclusion, while most Canadians appear to understand that one of the high-risk forms of distracted driving (i.e., texting while driving) is indeed dangerous, there is a minority who are unaware of, or resistant to, this fact. Practical Applications: Enforcement activities and education initiatives to combat distracted driving ought to be tailored to the target audience based on the patterns uncovered.     

Mechanism of the uptake of metal cations by Algal Cell Walls

Nondisintegrated sprayed dried cells of Scenedesmus obliquus have been applied for the study of the cumulation of metal cations. It has been found that algal cell walls behave predominantely as polyfunctional weakly acidic cation exchangers. Equilibrium constants for different exchange reactions have been determined radiometrically which allow to calculate the form of algal cell walls in various experimental conditions. Metal cations present in microconcentrations may be cumulated predominantly by another cell wall ligands in comparison with the cumulation of macroconcentrations of the same cations.     

Changes in the cell size of the diatom Cylindrotheca closterium in a hyperhaline pond

Cell length of the diatom Cylindrotheca closterium (Ehr.) Reimann & Lewin was investigated on a fortnightly basis from January to April 2000 in a hyperhaline pond (Sardinia, Mediterranean Sea) and relationships, with changes in temperature, salinity, and nitrite concentrations were assessed using single and multiple regression analyses. Results of our study indicate that C. closterium cell size was inversely related to temperature changes, but that salinity and nitrite concentrations may have a major idiosyncratic effect on cell size variability.     

Cell size dependent toxicity thresholds of polycyclic aromatic hydrocarbons to natural and cultured phytoplankton populations

The toxicity of pyrene and phenanthrene to phytoplankton was studied by analyzing the effect on the growth, abundance and cell viability of cultured species and natural communities of the Atlantic Ocean and the Mediterranean Sea. A decrease in cell abundance, and growth rate was observed as concentration of PAHs increased, with catastrophic cell mortality induced at the highest PAH concentration tested. A strong positive linear relationship was observed between the LC50 (the PAH concentration at which cell population will decline by a half), and the species cell volume, for both phenanthrene and pyrene. Natural communities were however significantly more sensitive to PAHs than cultured phytoplankton, as indicated by the lower slope (e.g. 0.23 and 0.65, respectively, for pyrene) of the relationship LC50 vs. cell volume. The results highlight the importance of cell size in determining the phytoplankton sensitivity to PAHs identifying the communities from the oligotrophic ocean to be more vulnerable.     

Trophic transfer of pyrene metabolites and nonextractable fraction from Oligochaete (Lumbriculus variegatus) to juvenile brown trout (Salmo trutta)

Cell lines of Etroplus suratensis established in our laboratory were evaluated for their potential use as screening tools for the ecotoxicological assessment of tannery effluent. The cytotoxic effect of tannery effluent in three cell lines derived from eye, kidney and gill tissue of E. suratensis was assessed using multiple endpoints such as Neutral Red (NR) assay, Coomassie Blue (CB) protein assay and Alamar Blue (AB) assay. Acute toxicity tests on fish were conducted by exposing E. suratensis for 96 h to tannery effluent under static conditions. The toxic effect of tannery effluent on the survival of fish was found to be concentration and time dependent. The tannery effluent at the concentration of 15% caused 100% mortality at 96 h whereas the lower concentration (0.5%) caused 13.33% mortality. The cytotoxicity of tannery effluent was found to be similar in the three cell lines tested, independent of the toxic endpoints employed. EC₅₀ values, the effective concentration of tannery effluent resulting in 50% inhibition of cytotoxicity parameters after 48 h exposure to tannery effluent were calculated for eye, kidney and gill cell lines using NR uptake, AB and cell protein assays. Statistical analysis revealed good correlation with r² = 0.95-0.99 for all combinations between endpoints employed. Linear correlations between each in vitro EC₅₀ and the in vivo LC₅₀ data, were highly significant p < 0.001 with r² = 0.977, 0.968 and 0.906 for AB₅₀, NR₅₀, and CB₅₀, respectively.     

X射线粉末法计算晶胞参数及粉末图指标化的微机程序

本文介绍了一个用BASIC语言编写的微机程序,即CDI程序。该程序是根据最小二乘修正加上外推的原理编制的,用于粉末衍射数据的晶胞参数计算和粉末图指标化。CDI程序可以处理所有晶系的衍射数据并得出令人满意的计算结果。程序已在IBMPC/XT,长城0520CH及C.S.重型微机上运行了好几年并解决了一系列实际问题。     

Better understanding of the activated sludge process combining fluorescence-based methods and flow cytometry: A case study

This study aims to demonstrate the validity of fluorescence-based methods, together with flow cytometry, as a complementary tool to conventional physicochemical analyses carried out in wastewater treatment plants (WWTPs), for the control of the currently largely unknown activated sludge process. Staining with SYTO 9, propidium iodide and 5-(and 6)-carboxy-2′,7′-difluorodihydrofluorescein diacetate (carboxy-H₂DFFDA) was used for cell viability and oxidative stress monitoring of the bacterial population forming the activated sludge of a WWTP. Throughout the period of research, several unstable periods were detected, where the non-viable bacteria exceeded the 75% of the total bacterial population in the activated sludge, but only in one case the cells with oxidative stress grew to 9%, exceeding the typical values of 2%–5% of this plant. These periods coincided in two cases with high values of total suspended solids (SST) and chemical oxygen demand (COD) in the effluent, and with an excess of ammonia in other case. A correlation between flow cytometric and physicochemical data was found, which enabled to clarify the possible origin of each case of instability in the biological system. This experience supports the application of bacterial fluorescence staining, together with flow cytometric analysis, as a simple, rapid and reliable tool for the control and better understanding of the bacteria dynamics in a biological wastewater treatment process.