PRODUCTION OF HETEROGENEOUS SUPERALKALI CLUSTERS Li n F (n= 2 -6) BY KNUDSEN -CELL MASS SPECTROMETRY

The superalkali clusters are important because they can be considered as potential building block for the assembly of novel nanostructured materials with unique structural, electronic, optical, magnetic, and thermodynamic properties. We have modified and used the Knudsen cell mass spectrometer in order to obtain and measurement of the ionization potentials of the superalkali clusters. In this work the clusters Li n F (n = 2 -6) have produces in the vapor over a mixture of lithium fluoride and lithium iodide by means of Knudsen cell which is placed into ionization chamber of the magnetic sector mass spectrometer. The simultaneous production and mass spectrometric detection of the ionic of clusters provide information on the conditions of formation and the distribution of these ion species. It is observed that the ions of clusters with an even numbered of lithium atoms are more stable than the ions of clusters with an odd numbered of lithium atoms. The clusters Li 5 F and Li 6 F were detected experimentally for the first time with their ionization energies of (4.29±0.25) eV, and (4.24±0.25) eV, respectively

A single dose of microplastic particles induces changed in organ weight of male Wistar rats

Increased plastic usage creates environmental problems due to its accumulation and degradation into microplastic particles (MP), less than 5 mm in diameter. Particles from various sources like food and beverages contaminated with polyethylene terephthalate (PET) could accumulate in different tissues exerting adverse effects. Since data regarding potential acute toxicity in doses that represent realistic/daily ingested MP doses are entirely lacking, male Wistar rats were exposed to a single dose (1.4, 35 or 125 mg/kg) of PET-generated MP by oral gavage. Changes in wet organ weight to body weight ratio of testicles, adrenal glands and kidneys were examined 24 h following the treatment. Results point to increased organ/body weight ratio of testicles in rats exposed to two higher MP doses, while adrenal glands were augmented only after treatment with 125 mg/kg. Further research is needed to gain insight into the underlying mechanisms of the observed phenomenon

The correlation between endothelin-1 levels and spirometry in dialysis patients compared to healthy subjects

Background and Aim. Several studies demonstrated a six-fold increase in plasma concentration of endothelin-1 (ET-1) in diaysis patients (hemodialysis and peritoneal dialysis) compared to healthy control subjects. However, the effects of ET-1 on respiratory function in these patients are less known. The aim of this study was to determine the potential differences in spirometric values in relation to ET-1 levels. Methods. The study included 28 patients (15 male, 13 female, mean age 55.9±16. 2 years) with end stage renal diseases (ESRD) receiving regular hemodialysis (HD), 23 patients (10 males, 13 females, mean age 55.8±15.8 years) with ESRD treated with continuous ambulatory peritoneal dialysis (CAPD) without any cardiovascular or respiratory diseases, and 30 healthy volunteers (14 male, 16 female, mean age 51.8±15.6 years) in control group. In each of the three groups the participants were divided into two additional sub-groups according to the serum levels of ET-1. The spirometry values were recorded before the onset of hemodialysis and prior to emptying the peritoneal cavity in CAPD patients. The results were analyzed using standard statistical methods (Student’s t-test). Results. Patients who were treated with HD or CAPD were found to have significant difference in values of most pulmonary function parameters between subjects with ET-1 levels lower than 6,6 pg/ml and subjects with ET-1 levels higher than 6,6 pg/ml. In the control group there was no difference in pulmonary function parameters in correlation with ET-1 levels. ET-1 values in patients of both dialysis groups were significantly higher compared to healthy subjects. Conclusions. Higher levels of ET-1 in dialysis patients over healthy subjects is associated with lower parameters of lung function tests. A possible pathophysiological mechanism for deterioration of pulmonary function might be explained by progression of inflammation, pulmonary oedema also known as “uraemic lung” or/and the progression of pulmonary hypertension

Effects of single orally administrated different sized microplastic particles – acute toxicity study in adult male rats

Introduction: As a result of human activity, the amount of plastic waste has increased immensely in the environment. While the main concern has been orientated toward visible litter, more recently fragments of plastic less than 5 mm in diameter, called microplastic particles (MP), raised the attention due to their ability to induce toxic effects in organisms. The toxicity of MP increases with a decrease in size since smaller sized particles are absorbed systematically and accumulated in different organs/tissues, including brain. Aim: Present study is designed to compare possible toxic acute effects of different sized MP, originating from polyethylene-terephthalate bottles, on toxicity signs, sensory-motor functions and relative brain weight in young male Wistar rats. Methods: Rats (n = 24) were divided in four experimental groups: (I) intact (controls); Q that orally received a 2.5 ml of Milli-Q; P1/P2 that were respectively orally administrated with 35 mg/kg of MP in median diameter of either 40 or 70 μm dissolved in a 2.5 ml of Milli-Q. 24 h after treatments, using toxicity clinical test, we assessed the agitation, convulsion, piloerection, sleepiness and lethargy. Parameters were valued as: – (no effect), + (mild effect), ++ (moderate effect) and +++ (major effect). Then, we evaluated sensory-motor functions by monitoring: consciousness (scored 0/1 point), respiration (scored 0/1), spontaneous activity (scored 0/1/2/3), forepaw outstretching (scored 0/1/2), climbing (scored 0/1), visual placing (scored 0/1), cage grasp (scored 0/1), gait posture (scored 0/1/2), geotaxis (scored 0/1), hearing (scored 0/1) and pacing/circling (scored 0/1). Total score was expressed as the sum of average scores of all investigated parameters and graded on the scale from 0 to 15. Then, rats were weighed and sacrificed, while their brains were carefully removed and weighed. The relative brain weights were calculated as the ratio of brain (wet tissue, mg) weight to body weight (g). For toxicity clinical testing a descriptive analysis was used while other data were analysed by One-way analysis of variance followed by Tukey’s posthoc test. Results were considered significant at p < 0.05. Results: Clinical toxicity signs were similar between groups while results of sensory-motor test point to unaltered sensory-motor functions upon MP treatments compared to controls (F (3, 20) = 0.9538; P = 0.4336). The absence of changes might be attributed to acute treatment, brief evaluation period and lack of cumulative effect upon MP treatments. Nonetheless, only smaller sized MP led to an increase in relative brain weight compared to controls (F (3, 20) = 3.425; P = 0.0369; p < 0.05) which might indicate the capability of smaller sized MP to cross blood-brain barrier and be accumulated in the brain inducing oxidative stress and inflammatory response. Although larger sized MP did not cause changes in relative brain weight, the possible modulations of additional parameters that were not the focus of this study should not be omitted. Conclusion: According to the presented results, even a smaller sized MP applied in a single dose could be harmful to health, thus, greater control of plastic usage and disposal is essential for humanity

Phonon-induced spin relaxation of conduction electrons in aluminum

Spin-flip Eliashberg function $\alpha_S^2F$ and temperature-dependent spin relaxation time $T_1(T)$ are calculated for aluminum using realistic pseudopotentials. The spin-flip electron-phonon coupling constant $\lambda_S$ is found to be $2.5\times 10^{-5}$. The calculations agree with experiments validating the Elliott-Yafet theory and the spin-hot-spot picture of spin relaxation for polyvalent metals.Comment: 4 pages; submitted to PR

Progesterone exerts protective effects in rat permanent bilateral common carotid artery occlusion model

Introduction: Cerebral hypoperfusion (CH), a reduced cerebral blood flow, characteristic for aging and neurodegenerative disorders, might be associated with a pro-oxidative state in the brain due to the generation of reactive oxygen species (ROS) that cause neuronal damage. These overgenerated pro-oxidants might be reduced, disabled and neutralized by the endogenous antioxidant enzymes, including superoxide dismutase (SOD) and catalase (CAT). A sex steroid hormone, progesterone, in several experimental models of neuronal injury exerts anti-oxidative properties upregulating anti-oxidative molecules and thus promoting neuroprotection. However, its efficacy in the state of CH is still unknown and it is necessary to better understand the mechanism underlying this hormone’s neuroprotective effects. Aim: We investigated whether progesterone is able to modulate CH-induced pro-oxidative/anti-oxidative imbalance, as well as SOD and CAT activities, in the prefrontal cortex of three-month-old male Wistar rats subjected to permanent bilateral common carotid artery occlusion (2VO). Methods: The appropriate actions were undertaken to reduce the distress of the animals in agreement with the European Community Council Directive of 86/609/EEC and 010/63/EU for animal experiments. All experimental procedures were allowed by the Ethical Committee for the Use of Laboratory Animals of VINČA Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Republic of Serbia (protocol authorization numbers 02/11 and 323-07-04253/2016-05). Following chloral hydrate anaesthesia, 8 rats randomly assigned in 2VO groups were double occluded with 5–0 silk suture, while 4 animals from sham operated group were subjected to the same surgical procedure but without actual ligation of carotid arteries. Four hours following the surgical procedure animals from sham operated group, used as controls, were subcutaneously treated with vehicle (commercial flax oil, 1 mg/kg/day, S + V), while animals in 2VO groups were subjected to either progesterone (1.7 mg/kg/day, 2VO + P) or vehicle (commercial flax oil, 1 mg/kg/day, 2VO + V). Following 7 days lasting treatments, pro-oxidative/anti-oxidative balance was assessed according to the method of Alamdari et al. [1]; while activities of anti-oxidative enzymes were determined as described in the study by Tatalović et al. [2]. One-way analysis of variance (ANOVA) test followed by Tukey’s post hoc test was employed to analyse data. The values of p < 0.05 or less were considered statistically significant. Results: Obtained results demonstrate that compared to controls, 2VO and vehicle treatment induced a significant increase of pro-oxidants levels (p < 0.01) as well as the activities of both investigated anti-oxidative enzymes, although only the CAT activity was significantly increased (p < 0.05). Following progesterone treatment, pro-oxidants levels were lowered to the control level which caused the difference between the 2VO groups (p < 0.05). In parallel, no statistically significant change in SOD activity was observed, while CAT was upregulated (p < 0.05). Conclusion: Presented results suggest that in the prefrontal cortex in the state of CH, progesterone, by modulating the CAT activity, downregulates overgenerated reactive species, reduces CH-induced oxidative stress and exerts anti-oxidative outcomes

Increasing transparency through the open city toolkit

Degbelo, A., Granell, C., Trilles, S., Bhattacharya, D., & Wissing, J. (2020). Tell Me How My Open Data Is Re-used: Increasing Transparency Through the Open City Toolkit. In S. Hawken, H. Han, & C. Pettit (Eds.), Open Cities, Open Data: Collaborative Cities in the Information Era (pp. 311-330). [Chapter 14] Springer Singapore. https://doi.org/10.1007/978-981-13-6605-5_14The Open Data movement has been gaining momentum in recent years, with increasingly many public institutions making their data freely accessible. Despite much data being already open (and more to come), finding information about the actual usage of these open datasets is still a challenge. This chapter introduces two tools of the Open City Toolkit (OCT) that tackle this issue: a tool to increase transparency and interactive guidelines. Interviews with city council employees confirmed the utility of the transparency tool. Both tools can be used by city councils (for planning purposes) and by users interested to know more about the value of current open datasets (for information purposes).authorsversionpublishe

Effects of chronic oral D-galactose treatment on general health status in male Wistar rats

D-galactose (d-gal) is an important physiological nutrient. According to the widely accepted aging metabolic theory d-gal at high levels can be converted into aldose and hydroperoxide, resulting in the overproduction of reactive oxygen species (ROS). Increased ROS levels may subsequently cause oxidative stress, inflammation, mitochondrial dysfunction, and apoptosis which are hallmarks of natural senescence as well as various pathological conditions. We investigated the effects of chronic oral d-gal intake (200 mg/kg and 500 mg/kg for 6 weeks) on physiological, neurological and toxicity parameters in 3 months old male Wistar rats. The obtained results indicate that body weight, food intake, serum glucose, neurological and toxicity status remained unaffected while urine proteins were significantly increased in d-gal treated rats. Although there was no effect on the general health status of the animals, our findings suggest that chronic oral d-gal administration may lead to renal dysfunction

Modulation of redox parameters in rat liver induced by flaxseed oil

Flaxseed oil, extracted from ripened flaxseeds, is functional food source that is associated with health benefits in many diseases, including cardiovascular, cancer, osteoporosis, etc. Besides saturated fatty acids and monounsaturated fatty acids, it also contains easily oxidized polyunsaturated fatty acids of the n-3 family. In current study, we tested the effects of commercial flaxseed oil in rat liver by measuring parameters related to free radical challenge (pro/antioxidant balance (PAB), lipid peroxidation (LPO) products and glutathione (GSH) level). Overall, applied treatment maintains general prooxidant load and antioxidant capacity since the level of PAB was unchanged. However, it exerts significant modulatory effect on particular redox parameters by increasing the amount of LPO products and consequently the susceptibility of tissue to free radical oxidative damage, which challenges the antioxidant defence system that in return elevates GSH concentration

Spin relaxation of conduction electrons in polyvalent metals: A realistic calculation

Relaxation of electronic spins in metals is significantly enhanced whenever a Fermi surface crosses Brillouin zone boundaries, special symmetry points, or lines of accidental degeneracy. A realistic calculation shows that if aluminum had one valence electron, its spin relaxation would be slower by nearly two orders of magnitude. This not only solves a longstanding experimental puzzle, but also provides a way of tailoring spin dynamics of electrons in a conduction band.Comment: 12 pages, 3 figures; to appear in PR