111 research outputs found
Penetratin and Derivatives Acting as Antibacterial Agents
The synthesis, in vitro evaluation and conformational study of penetratin and structurally related derivatives acting as antibacterial agents are reported. Among the compounds evaluated here, two methionine sulphoxide derivatives (RQIKIWFQNRRM[O]KWKK-NH2 and RQIKIFFQNRRM[O]KFKK-NH2) exhibited the strongest antibacterial effect in this series. In order to better understand the antimicrobial activity obtained for these peptides, we performed an exhaustive conformational analysis using different approaches. Molecular dynamics simulations were performed using two different media (water and trifluoroethanol/water). The results of these theoretical calculations were corroborated using experimental CD measurements. The electronic study for these peptides was carried out using molecular electrostatic potentials obtained from RHF/6-31G(d) calculations. In addition, the non-apeptide RQIRRWWQR-NH2 showed strong inhibitory action against the Gram-negative and Gram-positive bacteria tested in this study
Mobilisation of arsenic from bauxite residue (red mud) affected soils: effect of pH and redox conditions
The tailings dam breach at the Ajka alumina plant, western Hungary in 2010 introduced ~1 million m3 of red mud suspension into the surrounding area. Red mud (fine fraction bauxite residue) has a characteristically alkaline pH and contains several potentially toxic elements, including arsenic. Aerobic and anaerobic batch experiments were prepared using soils from near Ajka in order to investigate the effects of red mud addition on soil biogeochemistry and arsenic mobility in soil–water experiments representative of land affected by the red mud spill. XAS analysis showed that As was present in the red mud as As(V) in the form of arsenate. The remobilisation of red mud associated arsenate was highly pH dependent and the addition of phosphate to red mud suspensions greatly enhanced As release to solution. In aerobic batch experiments, where red mud was mixed with soils, As release to solution was highly dependent on pH. Carbonation of these alkaline solutions by dissolution of atmospheric CO2 reduced pH, which resulted in a decrease of aqueous As concentrations over time. However, this did not result in complete removal of aqueous As in any of the experiments. Carbonation did not occur in anaerobic experiments and pH remained high. Aqueous As concentrations initially increased in all the anaerobic red mud amended experiments, and then remained relatively constant as the systems became more reducing, both XANES and HPLC–ICP-MS showed that no As reduction processes occurred and that only As(V) species were present. These experiments show that there is the potential for increased As mobility in soil–water systems affected by red mud addition under both aerobic and anaerobic conditions
Advances in Understanding Environmental Risks of Red Mud After the Ajka Spill, Hungary
In the 5 years since the 2010 Ajka red mud spill (Hungary), there have been 46 scientific studies assessing the key risks and impacts associated with the largest single release of bauxite-processing residue (red mud) to the environment. These studies have provided insight into the main environmental concerns, as well as the effectiveness of remedial efforts that can inform future management of red mud elsewhere. The key immediate risks after the spill were associated with the highly caustic nature of the red mud slurry and fine particle size, which once desiccated, could generate fugitive dust. Studies on affected populations showed no major hazards identified beyond caustic exposure, while red mud dust risks were considered equal to or lesser than those provided by urban dusts of similar particle size distribution. The longer-term environmental risks were related to the saline nature of the spill material (salinization of inundated soils) and the release and the potential cycling of oxyanion-forming metals and metalloids (e.g., Al, As, Cr, Mo, and V) in the soil–water environment. Of these, those that are soluble at high pH, inefficiently removed from solution during dilution and likely to be exchangeable at ambient pH are of chief concern (e.g., Mo and V). Various ecotoxicological studies have identified negative impacts of red mud-amended soils and sediments at high volumes (typically [5 %) on different test organisms, with some evidence of molecularlevel impacts at high dose (e.g., genotoxic effects on plants and mice). These data provide a valuable database to inform future toxicological studies for red mud. However, extensive management efforts in the aftermath of the spill greatly limited these exposure risks through leachate neutralization and red mud recovery from the affected land. Monitoring of affected soils, stream sediments, waters and aquatic biota (fungi, invertebrates and fish) have all shown a very rapid recovery toward prespill conditions. The accident also prompted research that has also highlighted potential benefits of red mud use for critical raw material recovery (e.g., Ga, Co, V, rare earths, inform), carbon sequestration, biofuel crop production, and use as a soil ameliorant
HIV risk behaviors among female IDUs in developing and transitional countries
Abstract Background A number of studies suggest females may be more likely to engage in injection and sex risk behavior than males. Most data on gender differences come from industrialized countries, so data are needed in developing countries to determine how well gender differences generalize to these understudied regions. Methods Between 1999 and 2003, 2512 male and 672 female current injection drug users (IDUs) were surveyed in ten sites in developing countries around the world (Nairobi, Beijing, Hanoi, Kharkiv, Minsk, St. Petersburg, Bogotá, Gran Rosario, Rio, and Santos). The survey included a variety of questions about demographics, injecting practices and sexual behavior. Results Females were more likely to engage in risk behaviors in the context of a sexual relationship with a primary partner while males were more likely to engage in risk behaviors in the context of close friendships and casual sexual relationships. After controlling for injection frequency, and years injecting, these gender differences were fairly consistent across sites. Conclusion Gender differences in risk depend on the relational contexts in which risk behaviors occur. The fact that female and male risk behavior often occurs in different relational contexts suggests that different kinds of prevention interventions which are sensitive to these contexts may be necessary.</p
Longitudinal Determinants of Consistent Condom Use by Partner Type Among Young Injection Drug Users: The Role of Personal and Partner Characteristics
We investigated the longitudinal influence of individual-, relationship- and social-level factors on condom use by partner type among young injections drug users (IDUs) enrolled in the Collaborative Injection Drug Users Study-III/Drug Users Intervention Trial (CIDUS-III/DUIT) from 2002 to 2004. Based on longitudinal analysis using generalized estimating equations (GEE), consistent condom use with main partners was more commonly reported among males and those with greater self-efficacy for condom use; main partner’s desire for pregnancy and needle sharing were negatively associated with consistent condom use. Among those with casual partners, having fewer sex partners was associated with consistent condom use. Positive attitudes toward condom use and partner norms supporting condom use were associated with greater consistent condom use with both partner types. These findings suggest that intervention strategies targeting individual- and partner-level factors may provide avenues for intervening upon sexual risks among young IDUs
Evidence-based hydro- and balneotherapy in Hungary-a systematic review and meta-analysis
Balneotherapy is appreciated as a traditional treatment modality in medicine. Hungary is rich in thermal mineral waters. Balneotherapy has been in extensive use for centuries and its effects have been studied in detail. Here, we present a systematic review and meta-analysis of clinical trials conducted with Hungarian thermal mineral waters, the findings of which have been published by Hungarian authors in English. The 122 studies identified in different databases include 18 clinical trials. Five of these evaluated the effect of hydro- and balneotherapy on chronic low back pain, four on osteoarthritis of the knee, and two on osteoarthritis of the hand. One of the remaining seven trials evaluated balneotherapy in chronic inflammatory pelvic diseases, while six studies explored its effect on various laboratory parameters. Out of the 18 studies, 9 met the predefined criteria for meta-analysis. The results confirmed the beneficial effect of balneotherapy on pain with weight bearing and at rest in patients with degenerative joint and spinal diseases. A similar effect has been found in chronic pelvic inflammatory disease. The review also revealed that balneotherapy has some beneficial effects on antioxidant status, and on metabolic and inflammatory parameters. Based on the results, we conclude that balneotherapy with Hungarian thermal-mineral waters is an effective remedy for lower back pain, as well as for knee and hand osteoarthritis. © 2013 The Author(s)
Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study
Izloženost genotoksičnim agensima iz životnog okoliša tijekom prenatalnog razvoja i djetinjstva
Health disorders and diseases related to environmental exposure in children such as cancer and immunologic disturbances (asthma, allergies) are on the rise. However, complex transplacental and prepubertal genotoxicology is given very limited consideration, even though intrauterine development and early childhood may be critical for elucidating the cancer aetiology. The foetus is transplacentally exposed to contaminants in food and environment such as various chemicals, drugs, radiochemically contaminated water and air. Target organs of xenobiotic action may differ between the mother and the foetus due to specific stage of developmental physiology and enzyme distribution. This in turn may lead to different levels of clastogenic and aneugenic metabolites of the same xenobiotic in the mother and the foetus. Adult’s protective behaviour is not sufficient to isolate children from radioisotopes, pesticides, toxic metals and metalloids, environmental tobacco smoke, endocrine disrupting chemicals, and various food contaminants, which are just a part of the stressors present in a polluted environment. In order to improve legislation related to foetus and child exposure to genotoxic and possibly carcinogenic agents, oncologists, paediatricians, environmental health specialists, and genotoxicologists should work together much more closely to make a more effective use of accumulated scientific data, with the final aim to lower cancer incidence and mortality.Unatoč velikim naporima da se smanji okolišna izloženost u djece se dalje bilježi trend porasta pojavnosti karcinoma i imunosnih poremećaja (astma, alergije). Premda su intrauterini razvoj i rano djetinjstvo kritično razdoblje za tumačenje etiologije nastanka karcinoma, transplacentalna i prepubertetna genotoksikologija
do danas su slabo istražene. Fetus je transplacentalno izložen brojnim fizikalnim i kemijskim čimbenicima: kontaminantima iz hrane i okoliša, radiokemijski kontaminiranoj vodi, zraku te lijekovima. Ciljna tkiva za djelovanje ksenobiotika mogu biti različita u majke i fetusa zbog različitosti u razvojnoj fiziologiji i distribuciji enzima. Zbog toga u organizmu majke i fetusa mogu nastati različite razine klastogenih i aneugenih metabolita istog ksenobiotika.
Zaštitna uloga odraslih u namjeri da spriječe negativne utjecaje onečišćenog okoliša na djetetovo zdravlje često je ograničena jer su radioizotopi, olovo, PCB, pasivno pušenje, živa, endokrino aktivne tvari, pesticidi i kontaminanti prisutni u svim životnim područjima tijekom razvoja i rasta djeteta. Kako bi se poboljšalo zakonodavstvo vezano uz izloženost djece genotoksičnim i vjerojatno kancerogenim tvarima, tijekom razvoja potrebna je bolja suradnja onkologa, pedijatara, stručnjaka zdravstvene ekologije i genotoksikologa.
Na taj način ostvarilo bi se uspješnije iskorištavanje postojećih znanstvenih podataka u cilju smanjenja incidencije karcinoma i mortaliteta
The effect of dopamine agonists on adaptive and aberrant salience in Parkinson's disease
Clinical evidence suggests that after initiation of dopaminergic medications some patients with Parkinson's disease (PD) develop psychotic symptoms, such as hallucinations and delusions. Here, we tested the hypothesis that the neurocognitive basis of this phenomenon can be defined as the formation of arbitrary and illusory associations between conditioned stimuli and reward signals, called aberrant salience. Young, never-medicated PD patients and matched controls were assessed on a speeded reaction time task in which the probe stimulus was preceded by conditioned stimuli that could signal monetary reward by color or shape. The patients and controls were re-evaluated after 12 weeks during which the patients received a dopamine agonist (pramipexole or ropinirole). Results indicated that dopamine agonists increased both adaptive and aberrant salience in PD patients, that is, formation of real and illusory associations between conditioned stimuli and reward, respectively. This effect was present when associations were assessed by means of faster responding after conditioned stimuli signaling reward (implicit salience) and overt rating of stimulus-reward links (explicit salience). However, unusual feelings and experiences, which are subclinical manifestations of psychotic-like symptoms, were specifically related to irrelevant and illusory stimulus-reward associations (aberrant salience) in PD patients receiving dopamine agonists. The learning of relevant and real stimulus-reward associations (adaptive salience) was not related to unusual experiences. These results suggest that dopamine agonists may increase psychotic-like experiences in young patients with PD, possibly by facilitating dopaminergic transmission in the ventral striatum, which results in aberrant associations between conditioned stimuli and reward
The worldwide NORM production and a fully automated gamma-ray spectrometer for their characterization
Materials containing radionuclides of natural origin, which is modified by
human made processes and being subject to regulation because of their
radioactivity are known as NORM. We present a brief review of the main
categories of non-nuclear industries together with the levels of activity
concentration in feed raw materials, products and waste, including mechanisms
of radioisotope enrichments. The global management of NORM shows a high level
of complexity, mainly due to different degrees of radioactivity enhancement and
the huge amount of worldwide waste production. The future tendency of
guidelines concerning environmental protection will require both a systematic
monitoring based on the ever-increasing sampling and high performance of gamma
ray spectroscopy. On the ground of these requirements a new low background
fully automated high-resolution gamma-ray spectrometer MCA_Rad has been
developed. The design of Pb and Cu shielding allowed to reach a background
reduction of two order of magnitude with respect to laboratory radioactivity. A
severe lowering of manpower cost is obtained through a fully automation system,
which enables up to 24 samples to be measured without any human attendance. Two
coupled HPGe detectors increase the detection efficiency, performing accurate
measurements on sample volume (180 cc) with a reduction of sample transport
cost of material. Details of the instrument calibration method are presented.
MCA_Rad system can measure in less than one hour a typical NORM sample enriched
in U and Th with some hundreds of Bq/kg, with an overall uncertainty less than
5%. Quality control of this method has been tested. Measurements of certified
reference materials RGK-1, RGU-2 and RGTh-1 containing concentrations of K, U
and Th comparable to NORM have been performed, resulting an overall relative
discrepancy of 5% among central values within the reported uncertainty.Comment: 21 pages, 4 figures, 6 table
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