57 research outputs found
Performance of Diversity System Output Signal in Mobile Cellular System in the Presence of alpha-mu all Short Term Fading and Gamma Long Term Fading
In this paper, wireless mobile communication system with macrodiversity reception is considered. Macrodiversity system is consisting of macrodiversity selection combining (SC) receiver and three microdiversity SC receivers. Propagation channel suffers alpha-mu short term fading and Gamma long term fading resulting in system performance degradation. Analytical closed form expression for average level crossing rate (LCR) of macrodiversity SC receiver output signal envelope is obtained Mathematical results are analyzed, presenting the influence of long term fading parameters and short term fading parameters on average level crossing rate. Obtained results can be used in the process of simulation and design of real-world environments mobile cellular telecommunication systems
Jedan primer poboljÅ”anja hidrauliÄke upravljivosti sistema za preÄiÅ”Äavanje vode
Water treatment plant "Å trand" consists of 24 filtration fields placed in two filtering plants, "Old" and "New". Filtering plants are supplied with water from two aeration tanks by pressurized pipeline. Present state of filtration fields operation is U-shaped vessel, considering the filtration fields as tanks (in hydraulic sense). Automatic system keeps the water level constant in the field by downstream control. Clogging of filter material increases the water level, and response of control unit is opening of downstream valve as compensation. The valve opening should represent the level of filter clogging. Unfortunately, since all filtration fields are hydraulically connected, the change of water level in one filter will reflect on state of all other filters, preventing the automatic system to function correctly. That was the reason why the system works unstable, and why there is no correct information on filter clogging status. The present paper deals with hydraulic solution of filtration fields separation including design of flume for flow rate measurement. The mathematical model of flow was also presented together with gained experience.U okviru postrojenja za preÄiÅ”Äavanje vode "Å trand" u Novom Sadu, nalaze se dvadeset i Äetiri filtarska polja. RasporeÄena su u dve filtarske stanice "Staru" i "Novu". Voda se u fitarska polja dovodi gravitaciono, cevovodima pod pritiskom, iz dva bazena za aeraciju. Automatski sistem upravljanja održava konstantan nivo u filtarskom polju pomoÄu nizvodnog regulacionog zatvaraÄa. Svako poveÄanje nivoa (usled zapuÅ”avanja ispune) automatika kompenzuje otvaranjem zatvaraÄa, Äija bi otvorenost trebala ujedno i da pokazuje stepen zaprljanosti ispune. Trenutno stanje je takvo da su sva filtarska polja hidrauliÄki spojena zbog potopljenosti dovodnih cevovoda tako da regulisanje nivoa nizvodnim zatvaraÄem na jednom filtru, utiÄe na nivo vode u svim ostalim filtrima. Ova Äinjenica dovodi do otežanog upravljanja, nestabilnosti u radu postrojenja, a stepen otvorenosti nizvodnog ventila nije direktno povezan sa stanjem ispune na odreÄenom polju. U radu je prikazano hidrauliÄko reÅ”enje razdvajanja polja sa projektovanjem mernog objekta, jednaÄine matematiÄkog modela, rezultati dobijeni na fiziÄkom modelu preliva, kao i neki problemi na koje se nailazilo u radu
Performance analysis of EGC combining over correlated Nakagami-m fading channels
In this paper, performance analysis of diversity technique with equal gain
combining method (EGC) with two branches for the detection of signals in
wireless communication systems is presented. In the following analysis, it is
assumed that the fading via channels is Nakagami-m correlated. The first
order statistical characteristics of the system are analysed. Useful formulae
for the probability density function (pdf) and cumulative distribution
function (CDF) of EGC output SIR are derived, and the effects of the fading
severity on the output signal are observed
Small Cell Neuroendocrine Tumor of the Larynx ā A Small Case Series
Neuroendocrine tumors are the most common nonsquamous types of laryngeal neoplasms. They are classified as typical carcinoids, atypical carcinoids, small-cell neuroendocrine carcinomas, and paragangliomas. The aim of the paper is to present four patients with small-cell neuroendocrine tumor arising in larynx. There were one woman and three men whose ages were 47ā77 years; all of them had metastases when first seen. The clinical presentation and management of such type of tumor are discussed. Small-cell neuroendocrine carcinomas are very aggressive neoplasms. Patients could benefit from surgery, but radiotherapy and chemotherapy remain the treatment of choice. Examination of a large series is
required to define the most useful diagnostic methods and the most successful treatment modalities
MoguÄnosti upotrebe pljuvaÄke kao dijagnostiÄke teÄnosti u stomatologiji
Saliva is a secretion of the salivary and mucous glands and is of major importance in the maintainance of oral health. Over the last few decades, saliva has been evaluated as a diagnostic fluid in medicine for determining systemic disease markers as well as for monitoring numerous drugs, narcotics, and hormones. The biochemical analysis of saliva is particularly important in dentistry. The estimation of the risk of appearance and diagnosis of disease, monitoring of disease progression, evaluation of therapy efficacy for caries, periodontitis, premalignant and malignant oral lesions, as well as infectious diseases of the oral cavity, can be assessed by analyzing different constituent: of saliva, individuals at risk of caries can be identified using test: that determine saliva flow rate, saliva buffer capacity, and colonization of the oral cavity by cariogenic bacteria. Today, these rapid and simple diagnostic tests are used routinely in caries risk determination. The study and use of saliva-based diagnostics have increased over the last few decades. Clinical testing of saliva shows much promise. However, there is a need for much additional research in this area, before the true clinical value of saliva as a diagnostic fluid in dentistry can be determined.PljuvaÄka je sekret pljuvaÄnih i mukoznih žlezda koji je znaÄajan za održavanje oralnog zdravlja. Poslednjih decenija sve viÅ”e se razmatra moguÄnost njene primene kao zamena krvi, odnosno krvnom serumu i plazme, radi dokazivanja pokazatelja sistemskih oboljenja, kao i za nadgledanje primene lekova, droga i hormona. Analiziranje biohemijskog sastava pljuvaÄke posebno je znaÄajno u stomatologiji za procenu rizika nastanka, praÄenja toka bolesti i kontrole rezultata primenjenog leÄenja zubnog karijesa, parodontopatije, oralnih karcinoma i infektivnih oboljenja usne duplje. U proceni rizika nastanka karijesa na zubima rutinski se izvode ispitivanja kojima se odreÄuju koliÄina izluÄene pljuvaÄke, njen puferski kapacitet i stepen kolonizacije usne duplje kariogenim vrstama bakterija. Jednostavnost izvoÄenja ovih ispitivanja omoguÄava da ih u stomatoloÅ”koj ordinaciji primenjuje lekar praktiÄar, Å”to predstavlja veliku pomoÄ u proceni rizika za nastanak zubnog karijesa. Zbog bliskog kontakta s oralnim tkivima, pljuvaÄka sadrži brojne biohemijske pokazatelje patoloÅ”kih procesa lokalizovanih u ovim tkivima (enzimi, imunoglobulini, ostali proteini, fenotipski pokazatelji). Ispitivanje pomenutih pokazatelja je znaÄajno kao dopuna kliniÄkom dijagnostikovanju ukoliko ono ne pruža dovoljno informacija
Transient bacteremia caused by Atopobium vaginae after caesarean delivery: Case report
Introduction: Genital microbiome of woman is still a puzzle to this day. It consists of a large number of different bacterial species and phenotypes that make up the normal genital flora, while in the cases of its change there is a predominance of certain, especially anaerobic species, which is the case with bacterial vaginosis. These types are mostly rare causing invasive infections, but under certain conditions can lead to severe infections, such as multiple parts of the genital tract, and to an unwanted outcome in the pregnancy. Case report: This paper presents an extremely rare case of transient bacteremia caused by Atopobium vaginae type in a patient following a cesarean section where empirical therapy gave a positive effect and the patient recovered and released home with healthy newborn. Conclusions: During the clinical work it is important to be aware of the different anaerobic species present in the genital tract of women microbiome like Atopobium vaginae and should adjust the empirical therapy, which was the case here
Association of Myeloperoxidase and the Atherogenic Index of Plasma in Children with End-Stage Renal Disease
Background: The aim of this study was to explore oxidative stress status, especially the enzyme myeloperoxidase in children with end-stage renal disease. Also, we investigated possible associations between the atherogenic index of plasma and these parameters. Methods: Lipid status parameters, oxidative stress status parameters, and myeloperoxidase concentration were measured in the sera of 20 children in the last stage of chronic renal disease (ESRD) and 35 healthy children of matching age and sex. The Atherogenic Index of Plasma (AIP) was calculated according to the appropriate equation. Results: We did not find any significant differences in myeloperoxidase concentrations between the investigated groups (p = 0.394). Oxidative stress parameters were, however, significantly higher in the patient group (p lt 0.001), as well as the atherogenic index of plasma (p lt 0.001). Myelo per oxidase concentration and advanced oxidation protein product (AOPP) concentration were independently associated with increased AIP in the patient group (p lt 0.05). Conclusions: Changes in AIP in children with ERSD are associated with the oxidative stress status and myeloper oxidase concentration
Alterations of HDL Particles in Children with End-Stage Renal Disease
Background: Unfavorable lipid profile presents one of most important risk factor for cardiovascular disease in renal pathology. Myeloperoxidase (MPO) as enzyme which oxidizes lipoproteins and paraoxonase1 (PON1) as anti-oxidative enzyme have been involved in pathogenesis of cardiovascular disease. In the present study we sought to assess oxidative stress status, lipoprotein subclasses distribution as well as functionality of high density lipoprotein (HDL) trough MPO/PON1 ratio in children with chronic kidney disease (CKD) and children after renal transplantation. Methods: PON1 activity and oxidative stress parameters were measured spectrophotometrically, while MPO concentration was determined using immunoassay. Separation of lipoprotein subclasses was performed by vertical gradient gel electrophoresis in 19 children with different stage of CKD and 19 post-transplantation patients (PT). Results: CKD patients had increased MPO/PON1 ratio and higher prevalence of smaller HDL subclasses when compared to PT subjects. Also, there was a significant positive correlation between MPO level and MPO/PON1 ratio with relative proportion of smaller HDL subclasses. Conclusions: Children with CKD have impaired HDL distribution that is improved after kidney transplantation. Since that measurement of HDL distribution and functionality arenot routinely available, MPO/PON1 ratio may be useful marker that could provide necessary information
Associations of Apgar score and size at birth with lipoprotein subclasses in juvenile obesity
N Background/aim: Juvenile obesity is associated with several metabolic abnormalities, one of them being atherogenic dyslipidemia. Suboptimal fetal growth is associated with obesity risk in childhood, but also with increased rate of metabolic diseases in later life. This study investigated associations of neonatal data (Apgar score, birth weight and birth length) with low-density lipoprotein and high-density lipoprotein (LDL and HDL) subclasses in a group of obese children, as well as a possible impact of breastfeeding duration on obesity-associated lipoprotein subclasses distributions. Materials and methods: We included 42 obese children, aged 14.2 +/- 2.1 years. LDL and HDL subfractions were separated by gradient gel electrophoresis and biochemical parameters were assessed by routine methods. Results: Compared with obese children with Apgar >= 9, the group with Apgar lt 9 had significantly higher percentages of small, dense LDL particles (P lt 0.05), due to reduced LDL I (P lt 0.01) and increased LDL III subclasses (P lt 0.05). Birth weight was positively associated with the proportions of LDL I particles (P lt 0.001), whereas birth height positively correlated with the amount of HDL 2b subclasses (P lt 0.05). The group of never or less than 3 months breastfed children had significantly smaller LDL size (P lt 0.01) and lower proportion of HDL 2a particles (P lt 0.05) than their >= 3 months breastfed peers. Conclusion: The results showed significant associations of neonatal characteristics with LDL and HDL particle distributions in obese children. In addition, our results point toward positive aspects of longer breastfeeding duration on lipoprotein particle distributions in obese children
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