We investigate the global asymptotic behavior of solutions of the system of difference equations xn+1 = (a+xn)/(b+yn), yn+1 = (d+yn)/(e+xn), n = 0,1,..., where the parameters a, b, d, and e are positive numbers and the initial conditions x0 and y0 are arbitrary nonnegative numbers. In certain range of parameters, we prove the existence of the global stable manifold of the unique positive equilibrium of this system which is the graph of an increasing curve. We show that the stable manifold of this system separates the positive quadrant of initial conditions into basins of attraction of two types of asymptotic behavior. In the case where a = d and b = e, we find an explicit equation for the stable manifold to be y = x.
We develop a many-body description of the nonadiabatic dynamics of quasiparticles in surface bands valid on an extremely ultrashort time scale by combining the formalism for the calculation of quasiparticle survival probabilities with the self-consistent treatment of the electronic response of the system. Applying this approach to the benchmark Cu(111) surface, we assess the behavior and intervals of preasymptotic electron and hole dynamics in surface bands and locate the transition to the asymptotic regime of the exponential quasiparticle decay characterized by the corrected Fermi golden rule-type of transition rate. The general validity of these findings enables distinguishing the various regimes of ultrafast electron dynamics that may be revealed in time resolved experiments.
In this paper we investigate the possible impact on the ecosystems of the active ingredients in pharmaceutical and personal care products (PPCPs). These molecules are in their nature biologically active substances whose effects, once released into the environment, remain unclear. Commonly used drugs and cosmetics have been detected in drinking and surface waters suggesting possible consequences for environment and human health. Considering the possible bioaccumulation in the food chain and chronic toxicity due to a combination effect it is necessary to better understand their environmental fate. Pharmacologically and cosmetic active substances involved in our study were chosen according to their wide application in central Europe and to their suspected toxicity and bioaccumulation (nonsteroidal anti-inflammatory drugs NSAIDs, sunscreen agents, antiseptics). For isolation and identification of the selected compounds GC-MS procedure has been developed in our laboratory. To determine the presence of PPCP in the Slovene aquatic environment, different water samples (river, potable, well, lake, sea, swimming pool and waste water) were analyzed. The results show that the average PPCP contamination in Slovenian waters is comparable to published results for Central and Western Europe. To understand the environmental fate of these substances we studied the biodegradation paths in controlled conditions using laboratory scale bioreactor facilities. Degradation experiments were made with spiked water samples of different concentrations of pollutants (1μg/L-1ng/L) starting with activated biomass from the active wastewater treatment plant. After 6 months of continuous operation, a steady removal of all observed compounds (NSAID representatives) was achieved (up to 90%). In the future other PPCP representatives will be studied and the reactor configuration will be optimized.
Surface and waste waters are complex mixtures that may contain thousands of different pollutants of different origins (industrial, agricultural and domestic). Many of them show toxic and/or genotoxic effects and are therefore potentially hazardous for humans and the environment. It is extremely difficult to quantify the risk associated with xenobiotics in environmental samples because they usually occur in concentrations too low to allow chemical analytical determination. Additionally, single and combined biological effects of most of the micropollutants are not known. The best approach to evaluate potential toxic/genotoxic risks of such mixtures is to use biological test systems with living cells or organisms that give a global response to the pool of micropollutants present in the sample. In this study we evaluated the cytotoxic/genotoxic potential of 51 different water samples (river, potable, well, lake, and waste waters) potentially contaminated with pharmaceutical and personal care products (PPCP). The samples were evaluated for their genotoxic potential with the bacterial SOS/umu test with Salmonella typhimurium TA1535/pSK1002 and for their cytotoxic potential with mammalian cell based MTT assay with human hepatoma (HepG2) cells. Genotoxicity of seven selected samples was further tested with the comet assay with metabolically competent HepG2 cells. The results from the present study confirmed that biological tests are indispensable for the reliable assessment of cytotoxic and genotoxic potential of surface and waste waters. There is also a need for chemical analytical characterisation of cytotoxic/genotoxic samples in order to identify and quantify the compounds responsible for the cytotoxicity/genotoxicity.
The position of mandible in centric relation is the initial position in prosthodontic rehabilitation. This fact is especially significant today when, due to development of implantology, the use of osseointegrated prostheses is increasingly discussed. The aim of the study is to define if the peak of the articulating surface of mandible in centric relation position is directed towards the zenith of madibular fossa, or is in the retroposition. The research was conducted on macerated human sculls in anthropometric system, based on objective measuring techniques and methods. The results showed that if the zenith of mandibular fossa is determined according to the vertical line of the Frankfurt horizontal, the peak of the mandibular caput articulating surface is in retroposition. The relation of the lower joint surface to the mandibular fossa zenith is the same on both right and left side. The correlation coefficient demonstrates a high correlation between the sides, highly significant with probability level of p<0,01. If the peak of mandibular fossa is determined according to the vertical line of the Frankfurt horizontal, the peak of the articulating surface of mandibular caput is in retroposition in relation to the peak of the upper jaw surface. This original scientific work will help better understanding of x-ray analysis and understanding of relationship of TMJ surfaces, what is necessary for treatment of TMD and occlusal imbalances.
It was performed electroneurographic (ENG) studies with surface electrodes and examined nervus medianus (NM) in 60 patients (38 females), average age of 50,28 years (X+/-SD=50,28+/-11), with clinical diagnosis of carpal tunnel syndrome (CTS) and at least one border or discrete abnormal value of conventional electrophysiological tests. It was also examined 57 healthy individuals (33 females) as control group, average age of 45,65 years (X+/-SD=45,65+/-9,68). The sensitivity and specificity of sensory-motor index (SMI), terminal latency index (TLI) and residual latency (RL) were calculated and compared. SMI is determinate by using following formula: distal distance (DD) (in cm)/distal motor latency (DML) (in ms) + sensory conduction velocity (SCV) (in m/s)/motor conduction velocity (MCV) (in m/s) of NM. SCV of NM was measured by antidromic technique in segment wrist-index finger and MCV of NM in forearm segment above wrist. SMI mean value of control group was 3,45 (X+/-SD=3,45+/-0,45) with lower limit of normal value 2,82 and in patients with CTS 2,13 (X+/-SD=2,13 +/-0,37). The sensitivity of SMI in patients with CTS was 98,51%. SMI is useful parameter in electroneurographical diagnosis of CTS and it's determination is easy and fast and specially important in cases with border or discrete abnormal values of other NM electrophysiological parameters, when SMI values can indicate incipient phase of CTS evolution. In rare cases (about 1%) of CTS with selective NM motor axons affection, SMI may have normal value (false negative result), but DML is always prolonged in this cases. SMI is not dependent on age and DD values in patients with CTS and control subjects.
The purpose of this study was to obtain age estimation formulae using the length of periodontosis, transparency of the root and root height in each tooth group for the current male population in Bosnia and Herzegovina and to compare these formulae with Lamendin's and Prince's formulae. The research was undertaken on 847 single rooted teeth from 200 identified deceased persons, individuals who died between the ages of 23 and 85 years. Periodontosis, transparency and root height were measured according to Lamendin's procedure. All teeth were grouped in two ways: according to the tooth groups and to the age groups. The highest coefficients of correlation are obtained for maxillary canines (R = 0,731) and mandibular canines (R = 0,706) and the maxillary lateral incisors showed the lowest mean error (ME = 6,63 years). In age groups, the lowest mean error was obtained in the 40-49 years age group (ME = 5,15 years). Equations developed in this study give statistically significantly better age estimations in comparison to the original Lamendin and Prince formulae for the whole sample as well as for each tooth group, except for mandibular central incisors. Age estimation with models developed for each tooth group (except for mandibular lateral incisors) was statistically significantly better than models based on the whole sample.
Physical effort is a strong physiological stimulus that provokes an increase in blood growth hormone (GH) concentration. Interactions between GH and body composition are very complex. Seven athletes and seven age-matched controls completed a single 30-min bout of upright cycling exercise (5 % of VO(2max).) in order to estimate the influence of body composition on serum GH concentration during exercise. The serum GH concentration was measured in blood samples by standard immunoradiometric (IRMA) method. Anthropometric measurements were used for the calculation of body composition. There were no significant differences in total body mass or body mass index between the groups. The athletes had significantly less fat and higher bone and muscle mass. Serum GH concentration was 2.39 times higher in the athlets versus the control in the period of rest. During acute exercise, the serum GH concentration increased in both groups. No statistically significant differences between the groups in serum GH concentration were found either during the exercise or in the recovery. No correlation between body composition and serum GH concentration was found. Body composition depends on the level of physical activities but if the total body mass is in physiologycal range it does not influence the serum GH response to acute exercise.
Diabetes mellitus can be looked upon as an array of diseases, all of which exhibit common symptoms. While pathogenesis of IDDM (insulin dependant diabetes mellitus) is well understood, the same is not true for diabetes mellitus type II. In the latter case, relative contribution of the two factors (insulin resistance or decreased insulin secretion) varies individually, being highly increased in peripheral tissues and strictly dependant on insulin for glucose uptake. Moreover, in patients with diabetes mellitus type II, disbalance at the level of regulation of glucose metabolism as well as lipid metabolism has been noted in skeletal muscles. It is normal to assume that in this type of diabetes, these changes are reflected at the level of total activity of enzyme creatine kinase. This experimental work was performed on a group of 80 regular patients of Sarajevo General Hospital. Forty of those patients were classified as patients with diabetes type I and forty as patients with diabetes type II. Each group of patients was carefully chosen and constituted of equal number of males and females. The same was applied for adequate controls. Concentration of glucose was determined for each patient with GOD method, while activity of creatine kinase was determined with CK-NAC activated kit. Statistical analysis of the results was performed with SPSS software for Windows. Obtained results point out highly expressed differences in enzyme activity between two populations examined. Changes in enzyme activity are more expressed in patients with diabetes type II. Positive correlation between concentration of glucose and serum activity of the enzyme is seen in both categories of diabetic patients which is not the case for the patients in control group. At the same time, correlation between age and type of diabetes does exist . This is not followed at the level of enzyme activity or concentration of glucose.
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