The cytotoxicity of nici2 for mammalian cells in culture†

The effects of NiCl₂ were studied in two human cell lines, HeLa and diploid embryonic fibroblasts as well as in V79 Chinese hamster cells and in L‐A mouse fibroblasts. NiCl₂ produces a dose‐dependent depression of proliferation, mitotic rate, and viability, accompanied by an increasing release of lactic dehydrogenase and stimulation of lactic acid production. The plating efficiency is reduced, as are DNA and protein synthesis and, to a lesser degree, RNA synthesis.

The cytotoxicity of NiCl₂ is comparable in degree to those of PbCl₂ and MnCl₂, but is weaker than those of HgCl₂ and CdCl₂. However, the different sensitivities of different cell lines must also be considered.

NiCl₂ effects are more severe in serum‐free medium than in medium containing serum or serum albumin indicating that serum constituents, notably albumin, bind the metal effectively and inhibit cellular uptake; this confirms earlier reports on the serum binding and slow uptake of NiCl₂.

Synchronized cells are most sensitive in the Gl and early S phases of the cell cycle. In the Painter test the depression of DNA synthesis persists following cessation of exposure to NiCI₂. These findings contribute an explanation for the known genotoxic effects of nickel.     

How age and sex drive the foraging behaviour in the king penguin

As predicted by life history theory, once recruited into the breeding population and with increasing age, long-lived animals should be able to manage more efficiently the conflict between self-maintenance and reproduction. Consequently, breeding performances should improve with age before stabilizing at a certain level. Using temperature–depth recorders and isotopic analysis, we tested how age affects the foraging behaviour of king penguin Aptenodytes patagonicus during one trip in the chick-rearing phase. Depending on sex and age, king penguins expressed two different foraging strategies. Older birds gained more daily mass per unit body mass than younger ones. Older females conducted shorter trips, dived deeper and performed more prey pursuits. They also had higher blood levels of δ¹⁵N than younger individuals and males indicating sex- and age-specific dietary regimes. However, we found no differences in carbon isotopic signature, suggesting that individuals exploited the same foraging areas independently of sex and age. Our results suggest that king penguins are able to increase the quantity of energy extracted with increasing age and that such a strategy is sex-related. Our study is the first to reveal of an interaction between age and sex in determining foraging efficiency in king penguins.     

Hydrogeochemical and biomedical insights into germanium potential of curative waters: a case study of health resorts in the Sudetes Mountains (Poland)

Germanium is considered to be a non-essential element; however, little is still known about its significance for living organisms. It exerts prophylactic and therapeutic effects in the treatment of serious diseases such as cancer, HIV infection, and others. Germanium does not exhibit acute toxicity, but, as it tends to accumulate in various organs and tissues, undesirable and even dangerous side effects have been reported after prolonged and/or high dosage application. In general, inorganic compounds of germanium are more toxic than its organic compounds. Further studies should be performed to elucidate the exact molecular mechanism of germanium action, to determine the safe and effective dose of germanium via curative/mineral waters, and to understand the applications and benefits of using germanium-enriched waters in balneotherapy. The geochemistry of curative (cold CO₂-rich, thermal) waters from spas in the Sudetes (Poland) was clarified in terms of components and mineral phases which might govern germanium. Germanium and silicon in thermal (above 20 °C) waters presumably result from the solubility of silicates in crystalline (granites, gneisses) aquifer rocks and might be controlled by neo-formed quartz. The cold CO₂-rich waters revealed a significant diversity of aqueous chemistry and relationships of germanium with iron, silicon, or arsenic. Locally, both in sedimentary (sandstones) and metamorphic (gneisses) aquifer rocks, primary (silicates) and/or secondary (oxides) iron-containing minerals likely release germanium into solution. In the CO₂-rich waters of the western part of the K?odzko Region, germanium distinctly correlates with arsenic. It is hypothesized that both elements are co-sourced from crystalline basement and/or migration of substances of post-magmatic origin along deep-seated dislocations related to the seismically active Po?í?í-Hronov fault zone. This area was proposed as the most prospective one for finding waters rich in germanium in the Sudetes.     

Changes in transport accessibility as a result of flooding: a case study of the Mazovia Province (Eastern Poland)

This paper presents the results of research investigating the impact of flooding on the temporal aspect of transport accessibility at national, regional and local levels in the Mazovia Province – an administrative region in Poland. For the purposes of this study the authors measured the theoretical journey times by private transport between settlement units for two variants: journeys made under normal circumstances, that is, without a flood; and journeys made during a flood event, which would necessitate diversions to avoid flooded road sections. This allowed the theoretical journey time differences to be calculated. It was assumed that vehicles move at the highest permissible speed along routes allowing the shortest travel times. The methods of accessibility assessment employed in this paper are based on distance measurements and use isochrones and a cumulative approach. Analysis carried out by the authors has shown that for interregional, intraregional and local journeys, the flooding of a part of the Mazovia region results in changes in travel times, but their absolute and relative magnitudes vary widely. It was found that in the case of national scale journeys the majority of relative journey time increases were no greater than three times the normal duration, while on a local scale they do not exceed 75%. For areas with a high risk of flooding there should be obligatory analyses of changes in transport accessibility; this would facilitate effective flood risk management. Appropriate traffic management in crisis situations would facilitate emergency and rescue services and help inhabitants and any other persons in flooded areas.     

An ecosystem model for estimating potential shellfish culture production in sheltered coastal waters

A generic ecosystem model has been developed for estimating the potential production of shellfish culture and the effect of that cultivation on the pelagic ecosystem in sheltered coastal waters. The model describes the dynamics of a simple food web, nutrient cycling and growth of shellfish. The design of the model is closely tied to the temporal and spatial scales that are important in determining the sustainable production level for a particular embayment. The pelagic ecosystem, mussel energetics, population dynamics and hydrodynamics are coupled to allow fully dynamic predictions of the effect of the shellfish density. When applied to Beatrix Bay, an intensive culture embayment in the Pelorus Sound of New Zealand, the model successfully captured main features of the observed system behaviour. The hydrodynamic regime of the bay controls mussel growth and production. Although high fluxes of water into the bay suppress nutrient and carbon cycling signals in the system, the model simulations demonstrated that the mussel cultivation can have considerable effects on the ecosystem of the bay including food depletion and nutrient cycling. One of the most obvious effects is nutrient enhancement through mussel excretion at low cultivation densities, which promotes primary production particularly during the N-limitation period in summer. The sensitivity analysis identified uncertainty in some parameters and indicated areas for which experimental studies could lead to model improvement. The modelling exercise has established a primary predictive tool for managing mussel aquaculture of a coastal embayment to estimate relationships between the stock level and the growth rate of mussels, and the potentially achievable harvest and stocking density.     

High-Velocity Stretching of Renewable Polymer Blends

Journal of Polymers and the Environment - We evaluated the influence of blending various renewable polymer grades and amounts to allow for high stretchability during stretching at 800 mm/s...     

The Influence of Anchor Devices on the Performance of Retractable Type Fall Arresters Protecting Against Falls From a Height

Retractable type fall arresters are part of the equipment used for protecting people against falls from a height. They are an intermediate part between full body harness worn by a man and the structural anchor at the worksite. The most important task of retractable type fall arresters is to arrest people’s falls and to reduce their harmful consequences. Information received from users as well as laboratories testing protective equipment indicates that the performance of such equipment is incorrect under specific conditions. The paper is concerned with an analysis of the conditions in which retractable type fall arresters demonstrate intermittent performance and with an explanation of that phenomenon. The results of tests investigating anchor devices and the performance of retractable type fall arresters are presented. External and internal factors contributing to intermittent performance have been determined and guidelines for safer use of these devices have been developed.     

Simulation of Reflected and Scattered Laser Radiation for Designing Laser Shields

This paper presents a computer simulation of reflected and scattered laser radiation for calculating the angle of laser shields performed with the Laser Shield Solver computer program. The authors describe a method of calculating the shield angle for laser shields which protect workers against reflected and scattered laser radiation and which are made from different materials. The main assumptions of the program, which calculates and simulates reflected laser radiation from any material and which can be used for designing shield angles, are presented. Calculations are compared with measurements of reflected laser radiation. The results for one type of laser and different materials which interacted with a laser beam showed that the Laser Shield Solver was an appropriate tool for designing laser shields and its simulations of reflected laser radiation distribution have practical use.     

Identification of Driver Model Parameters

The paper presents a driver model, which can be used in a computer simulation of a curved ride of a car. The identification of the driver parameters consisted in a comparison of the results of computer calculations obtained for the driver-vehicle-environment model with different driver data sets with test results of the double lane-change manoeuvre (Standard No. ISO/TR 3888:1975, International Organization for Standardization [ISO], 1975) and the wind gust manoeuvre. The optimisation method allows to choose for each real driver a set of driver model parameters for which the differences between test and calculation results are smallest. The presented driver model can be used in investigating the driver-vehicle control system, which allows to adapt the car construction to the psychophysical characteristics of a driver.     

Deposition and Retention of Ultrafine Aerosol Particles in the Human Respiratory System. Normal and Pathological Cases

The particle number concentration in ambient air is dominated by nanometersized particles. Recent epidemiological studies report an association between the presence of nanoparticles in inhaled air at the workplace and acute morbidity and even mortality in the elderly. A theoretical model of deposition of 20 nm particles in the human alveolus was formulated. Gas flow structure and deposition rate were calculated for alveoli with different elastic properties of lung tissue. Data obtained in the paper show increased convective effects and diffusional rate of deposition of nanoparticles for alveoli with higher stiffness of the alveolar wall. The retention of deposited particles is also higher in these pathological alveoli. Results of our calculations indicate a possibility of existence of a positive loop of coupling in deposition and retention of nanoparticles in the lung with pathological changes.