Context: Cadmium is an important predictor of lung function, including forced vital capacity, forced expiratory volume and peak flow. Current evidence supports the notion that cadmium may be an important risk factor for cardiovascular fitness. Objectives: The purpose of this study was to determine the effect of cadmium exposure on cardiovascular fitness in representative sample of US white, blacks and Mexican Americans. The study also sought to determine if the relationship between cadmium and cardiovascular fitness varies by gender and racial/ethnic group. Methods: The data utilized for this study were obtained from National Health and Nutrition Examination Survey (NHANES). One-thousand nine hundred and sixty three subjects with data on cardiovascular fitness were eligible for this investigation. In NHANES, cardiovascular measurements were taken in series consisting of two minutes warm up exercise, two-three minutes exercise testing and two minutes resting period .The goal was to elicit 75% of predetermined age-specific heart rate by the end of the stress test. Cadmium was measured in the laboratory by taking urine sample of participants. Gender and race/ethnic specific multivariate linear regression analyses were performed to determine relationship of urinary cadmium with VO2 max. Results: There were gender and racial/ethnic difference in the relationship between urinary cadmium and VO2 max. In males and females, increased concentration of urinary cadmium was associated with decreased VO2 max across racial/ethnic groups (except in black males. The greatest negative association between cadmium and VO2 max was observed in black females (beta=-0.330) while the lowest value was recorded for white females (Beta=-0.074). The association was statistically significant in white males (Beta=-0.402, P =0.020) and Mexican American females (Beta=-0.290, P=0.026). Conclusion: There was inverse association between urinary cadmium and estimated VO2 max in a US nationally representative sample of White, Black and Mexican Americans. The impact of the gender and racial/ethnic differences in the association between urinary cadmium and VO2 max is not clear and warrants further investigation.

The subject matter of the Master thesis is the potential unemployed, who will loose their source of living after the decommissioning of the Ignalina Nuclear Power Plant, their expectations concerning social guarantees, which are provided for in the policy carried out by the Republic of Lithuania in this particular case. With the view to fulfilling the tasks set in the thesis, literature and other sources on the topic in the Internet, social studies on the decommissioning of the Nuclear Power Plant were analysed, interviews with the employees of the nuclear power plant, who will gradually loose their jobs due to the decommissioning of the power plant, were conducted. The Master thesis consists of three parts. The first part considers the problems encountered by the potential unemployed due to the integration of Lithuania into the European Union, threats posed by the increased competition of labour force and free movement of labour in the European Union area, social consequences of loosing a job and former social status, as well as problems relating to the necessity of re-qualification and taking new personal initiatives in order to cope with the threat of unemployment. The second part reviews the legal acts, following which the potential unemployed can hope for social security after the decommissioning of the Nuclear Power Plant, social studies and readiness of the Ignalina Nuclear Power Plant region and Visaginas town to meet the future changes in the labour market, and... [to full text]

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Lietuvos valstybėje vienas iš svarbiausių ir reikšmingiausių kultūriniu rekreaciniu palikumu yra Trakų rajonas. Šis kraštas išsiskiria iš visos valstybės tuo, kad jame yra saugoma kopmpleksinės apsaugos objektai – ir gamtiniai ir kultūriniai. Tai nulėmė šio krašto gili istorinė praeitis ir dėkinga geografinė padėtis. Šio darbo svarbumas yra tame, kad nagrinėjamas kultūrinis rekreacinis potencialas yra visame Trakų rajone ir analizuojama per dvi sritis - saugomas teritorijas ir administracines rajono ribas. Taip pat labai svarbu tai, kad darbas yra pritakytas edukaciniam panaudojimui. Rajono istorinei ir teritorinei raidai didžiausios įtakos turėjo geografinė padėtis ir istoriniai vingiai, nulėmę visos Lietuvos ir įpatingai pietrytinės dalies užgrobimus, okupaciją ir padalijimus. Didžiausias indėlis į rekreacijos plėtrą yra padarytas 1991 metais įsteigtus Trakų istorinį nacionalinį parką. Čia saugomi įpatingos reikšmės ir svarbos Lietuvos is¬toriniam valstybingumui kultūriniai ir gamtiniai kompleksiniai objektai. Taip pat daug padaryta 1992 metais įsteigtus Aukštadvario ir Neries regioninius parkus. Čia saugomos kultūros paveldo vertybės, gamtinė aplinka ir apylinkių kraš¬tovaizdis. Ištyrus Trakų rajono kultūrinį rekreacinį potencialą seniūnijų ribose, galima teigti, kad turtingiausias ir vertingiausias palikimas yra Trakų seniūnijoje. Ji išsiskiria iš visų aštuonių rajono seniūnijų savo istorinėmis, architektūrinėmis, archeologinėmis, gamtinėmis vertybėmis. Taip pat... [toliau žr. visą tekstą] / Trakai district is one of the most important ones in Lithuania from the point of view of its recreational and cultural heritage. This land is exceptional because it comprises the objects of complex protection – both natural and cultural. This was influenced by rich historical background of the land and its beneficial geographical position. What makes this final paper significant is that the analyzed cultural recreational potential covers the whole Trakai district and is investigated through two areas – the protected territories and the administrative borders of the district. It is also important that the paper is adapted for educational purposes. The geographical position and historic evolution (that determined the occupation and division of the whole Lithuania, especially its south-eastern part) had the biggest influence on historic and territorial development of the district. The biggest contribution to the development of recreation was made in 1991 when Trakai Historical National Park was established. It protects cultural and natural objects that are of special importance for Lithuanian historical statehood. Much work was also did in 1992 when Aukštadvaris and Nėris regional parks were established. The cultural heritage valuables, natural surroundings and local scenery is protected here. Having analyzed Trakai district cultural recreational potential it is possible to state that Trakai ward has the richest and the most valuable heritage. It stands out of all eight district... [to full text]

Šiandien dėl sėslaus gyvenimo būdo blogėja vaikų fizinė būklė, nuolat susiduriama su sveikatos problemomis. Todėl būtina daug aktyviau siekti kūno kultūros tikslų: ugdyti mokinius, motyvuoti būti fiziškai aktyviais, ugdyti jų pasitikėjimą savimi, puoselėti jų požiūrį į sveiką gyvenseną, jos propagavimą ir kūno stiprinimą. Fizinis aktyvumas yra svarbiausias veiksnys, skatinantis organizmą augti ir tobulėti. Kiekviena judėjimo forma optimizuoja žmogaus ne tik motorikos, bet ir jo psichinės bei socialinės brandos vyksmą. Moksliškai nustatyta, kad fizinis pajėgumas, aktyvumas ir sveikata yra labai glaudžiai susiję. Todėl gvildenamos fizinio pajėgumo problemos atskleidžia nagrinėjamos temos aktualumą. Tyrime dalyvavo 7–9 metų amžiaus mokiniai (51 mergaitė, 52 berniukai). / Nowadays when the life is getting more and more sedentary, children physical state is getting worse too, health disorder issues happen to be more often. That’s why it is a must more actively seek for the main physical culture aims: educate pupil, motivate them to be physically active, develop their self – confidence, foster their attitude for the healthy life, propagate it and all in all strengthen their body. In this case the main factor is a physical activity, which allows organism to grow and improve. Every kind of movement optimizes not only person’s motility, but also his mental and social mutuality growth. It was approved scientifically that physical potential, physical activity and health is very close link. That’s how solving the issues of the physical potential problems reveal the actuality of this work. 7-9 years age pupil were questioned in this investigation (51 girl, 52 boys). The object of the research: Physical potential of girls and boys.

Processing information in the nervous system is energetically expensive, constraining the ability of the system to survive disturbances caused by stress. While some organisms compensate for extreme changes in the abiotic features of their environment, the mechanisms underlying this are poorly understood. We used the locust Descending Contralateral Movement Detector (DCMD) neuron to study how the propagation characteristics of action potentials (APs) change following an acute energy stress in control and heat shock (HS) pre-treated animals. We also attempted to determine if Ca2+ is involved in the DCMD AP and the possible changes indicated above. Conduction velocity decreased over an hour of recording in all groups, except those with minimal dissections, and we observed an increase in AP half-width and a decrease in the slope of the rising phase of the AP over time. After HS pre-treatment the response to a standard looming stimulus was delayed, showed significantly fewer APs and a lower peak frequency compared to controls. Brief application of sodium azide (NaN3) as an acute metabolic inhibitor did not subsequently affect DCMD’s conduction velocity or ability to fire at high frequencies during the recording period. There were no significant differences from control animals with extracellular Ca2+ manipulations; however we cannot conclude that Ca2+ does not contribute to DCMD’s AP because Na+ could have flowed through Ca2+ channels in the absence of extracellular Ca2+. Furthermore, examination of possible performance impairments with decreased Ca2+ currents, to indicate if Ca2+ current manipulation may account for the performance impairment, could not be conducted because no differences in AP characteristics were observed with Ca2+ manipulations. We suggest that the slowing of propagation in all groups represents a response to energetic stress and that HS modifies neuronal properties in ways that can be interpreted as saving energy in case of future stressors. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2009-08-11 08:36:26.571

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Nanotechnology as a science is emerging rapidly. As materials are synthesized and utilized at the nanometer size scale, concerns of potential health and safety effects are arising. In an effort to elucidate the physicochemical characteristics of nanoparticles influential in toxicological studies, surface properties of metal oxide and carbonaceous nanoparticles were measured. These properties include zeta potential, dissolution and surface-bound chemical components. Subsequently, the role of these properties in oxidative stress was examined in vitro. This work identifies the influence that pH has on the zeta potential of nanoparticles. The zeta potential has the ability to alter colloidal stability, as the largest nanoparticle agglomerate is seen at or near the isoelectric point for each of the particles tested. Furthermore, it was observed that metal oxide nanoparticles which exhibit a charged surface at physiological pH, lead to decreased in vitro cellular viability as compared to those that were neutral. Thus, nanoparticle zeta potential may be an important factor to consider when attempting to predict nanoparticle toxicity. Real world exposure to nanoparticles is a mixture of various particulates and organics. Therefore, to simulate this particle mixture, iron oxide (Fe2O3) and engineered carbon black (ECB) were utilized in combination to identify potential synergistic reactions. Following in vitro exposure, both nanoparticle types are internalized into endosomes, where liberated Fe3+ reacts with hydroquinone moieties on the ECB surface yielding Fe2+. This bioavailable iron may then generate oxidative stress through intracellular pathways including the Fenton reaction. As oxidative stress is common in particulate toxicology, a comparison between the antioxidant defenses of epithelial (A549) and mesothelial (MeT-5A) cell lines was made. The A549 cell line exhibits alterations in the NRF2-KEAP1 transcription factor system and therefore retains high basal levels of phase II antioxidants. Both cell types were exposed to 33 nm silica where intracellular oxidant generation coupled with markers of oxidative stress were observed. While the MeT-5A cells exhibited a decrease in cell viability, the A549 cell line did not. Therefore, proper characterization of both material and biological systems prior to toxicity testing will help to further define the risks associated with the use of nanotechnology.

Polymeric nano and microparticles are important tools for an increasing variety of applications in the life sciences such as cellular delivery, sensing and imaging, with a fundamental requirement being particle functionalisation. Herein, the use of zeta potential measurements is described as a convenient tool to allow a variety of chemical reactions to be rapidly monitored on particles. To allow multifunctionalisations these particles need to be orthogonally modified. As part of this thesis, novel dual-functionalised aminomethyl and boronic acid particles were synthesised. These particles could be modified via amide formation and palladiummediated cross coupling, with applications demonstrated in cellular delivery and cellbased cargo release. The requirement for bright fluorescent particles for applications in the life sciences was addressed by the synthesis and analysis of particles prepared using polymerisable fluorescein derivatives. Although nanoparticles are a promising technology to solve a variety of problems, their behaviour in biological systems is not fully understood. Herein, the effects of the particle’s surface chemistry on cellular uptake and toxicity were investigated.

The presented studies investigate dynamics of action potential duration (APD) tobetter understand the underlying mechanism for repolarization alternans.We recorded trans-membrane potentials (TMP) in canine endocardial muscle tissueusing standard glass microelectrode under the control of an explicit diastolic interval (DI)control pacing protocol, i.e. feedback protocol. During sequential sinusoidal DI activation,the trajectory of APD dynamics has multiple values of APD correspondent to the sameDI, i.e. restitution is a bi-modal relationship. Our results indicate that: 1) there is a delay,similar to hysteresis, of change in APD responding to change in DI, 2) and the timecourse of the delay is asymmetric for fast or slow pacing history. The alternans wasobserved during constant DI pacing, i.e. the DI preceding each APD was invariant orchanged within a limited range. This finding suggests that alternans of APD do not needthe oscillation of preceding DI, i.e. DI dependent restitution is not a necessary conditionfor the alternans. This result implies that DI independent component exists in themechanism of the alternans. Nonetheless, the amplitude of alternans was statisticallylarger during constant pacing cycle length (PCL) pacing than that during constant DIpacing, even though both PCL and DI pacing trials used similar average activation rate.These results also demonstrate the ability of the feedback protocol to analyze the memoryeffects and dissect different components in the mechanism of alternans.Two computational models, Luo-Rudy dynamics (LRD) and cardiac ventricle model(CVM) were used to study the hysteresis in restitution. By perturbing membrane current:L-type calcium current, rapid and slow potassium rectifier, and intracellular calciumtransfer rate in sarcoplasmic reticulum (SR) and using sinusoidal DI pacing sequence, weshowed that the asymmetric calcium current across the membrane and its interaction withcalcium buffer in SR during increasing and decreasing DI phase plays an important rolein the hysteresis. CVM was used to study the alternans during constant DI pacing.However CVM failed to replicate the alternans that occurred in the experiments. Thisresult implies that CVM lacks the electrophysiological kinetics related to alternans thatwas shown in our experiment.