OPTIMIZATION AND PERFORMANCE ANALYSIS OF THE 30-BIT FIXED-POINT DIGITAL FORMAT

The 32-bit floating-point format (FP32) is standardly used for digital representation of data in computers, providing high quality of digital representation in a very wide dynamic range of data. However, the FP32 format has a very high computational complexity, requiring the use of expensive and powerful hardware, as well as high energy consumption. Hence, the implementation of the FP32 format on devices such as smart sensors, embedded and edge devices that have limited hardware resources becomes very problematic. On the other hand, the fixed-point format has significantly less computational complexity, consumes less power, requires less area on chip and provides faster calculations than the floating-point format, being much more suitable for implementation on devices with limited hardware resources.The main goal of this paper is to find a fixed-point format that will be a good replacement for the FP32 format, in the sense that it provides the same performance as the FP32 format and at the same time significantly reduces the computational complexity. Therefore, the paper considers the 30-bit fixed-point format, optimizes the value of its parameters and evaluates its performance, using the analogy between the fixed-point digital representation and uniform quantization. As the main result, the paper shows that the 30-bit fixed-point format can achieve a better quality (i.e. higher SQNR) of digital representation for 3.352 dB compared to the FP32 format, saving at the same time 2 bits per each piece of data (which can be a significant saving for a large amount of data) and significantly reducing the complexity of the implementation. Therefore, the proposed 30-bit fixed-point format can be successfully used as a replacement for the FP32 format on devices with limited resources

DESIGN AND ANALYSIS OF DIFFERENT TECHNIQUES FOR ANALOG-TO-DIGITAL CONVERSION OF VIBRATION SIGNALS FOR WIRELESS MEASUREMENT SYSTEMS

The aim of this paper is to design, analyze and compare four different systems for ADC (analog-to-digital conversion) of vibration signals. Measurement of vibration signals is of particular importance in many areas, such as predictive maintenance or structural health monitoring. Wireless systems for vibration measurements becomes very topical, due to much easier and cheaper installation compared to wired systems. Due to the lack of transmission bandwidth and energy in wireless measurement systems, the amount of digital data being sent has to be reduced; hence, we have to apply ADC systems that can achieve the required digital signal quality, reducing the bit-rate. Four ADC systems are analyzed, for possible application in wireless measurement systems: PCM (pulse code modulation) based on uniform quantization; DPCM (differential PCM) to exploit high correlation of vibration signals; two adaptive ADC systems to cope with significant variations of characteristics of vibration signals in time - APCM (adaptive PCM) with adaptation on variance and ADPCM (adaptive DPCM), with double adaptation (both on variance and correlation). These ADC models are designed and optimized specifically for vibration signals, based on the analysis of 20 vibration signals from a referent database. An experiment is done, applying designed ADC systems for digitalization of vibration signals. APCM, DPCM and ADPCM systems allow significant bit-rate reduction compared to the PCM system, but with the increasing of complexity, hence the compromise between the bit-rate reduction and complexity is needed

Primary percutaneous transluminal coronary angioplasty in the acute infarction of the right ventricle

Background. Predilection site for the acute myocardial infarction of the right ventricle, (AMI-RV) is the upper third of the right coronary artery and for this reason such an infarction is followed by numerous complications, primarily by conduction disorders and very often by sudden and rapid cardiogenic shock development. Methods. Primary percutaneous transluminal coronary angioplasty (PPTCA) was performed on three patients in whom the acute infarction of the right ventricular was diagnosed and who had been hospitalized six hours after the beginning of chest pain. In all three patients intracoronary stent was implanted. On the admission patients had been in the threatening cardiogenic shock, with the prominent chest pain and with the elevation of ST-segment in V4R>2 mV. In the course of intervention patients were administered low-molecular intracoronary heparin with direct platelet glycoprotein IIb/IIIa inhibitors (abciximab), according to the established procedure applied in such cases. Results. The complete dilatation of the infarcted artery was established with the signs of reperfusion and the further clinical course was completely normal, there was no heart failure and patients had no subjective difficulties. Conclusion. Invasive approach in the treatment of AMI-RV is justifiable, and possibly the therapy of choice of these patients, providing well trained and equipped team is available

Odnos između parametara gojaznosti i vrednosti C-reaktivnog proteina kod predgojaznih i gojaznih žena

Background/Aim. Overweight/obesity has become important health problem in developed countries. It may be related to a presence of low-grade inflammation in white adipose tissue. The aim of this study was to investigate the levels of inflammatory marker C-reactive protein (CRP) and its relation to anthropometric parameters in overweight and obese females. Methods. This study included 200 apparently healthy, overweight and obese women (18-45 years). Their standard and alternative anthropometric parameters [body mass index (BMI), percentage of fat (%F), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body adiposity index (BAI)] were determined and correlated to serum CRP concentration. Results. Average CRP level was 5.56 ± 2.43 mg/L, and it significantly positively correlated to all investigated anthropometric parameters. There was significant difference between overweight and obese group in all investigated anthropometric parameters, as well as in CRP values. When investigated separately, according to BMI, values regarding obese females showed significant correlation between CRP and every investigated anthropometric parameter. In overweight subjects, no such correlation was recorded. In the obese group, all investigated parameters were significantly related to F. In overweight subjects, body weight (BW), BMI, WC and WHtR showed significant relation to F. Conclusion. The significant difference between the overweight and obese group in all parameters of central obesity was found as well as in the CRP levels. In the obese group, we found strong correlation between adiposity measured by fat percentage and parameters of central obesity, while in the overweight group WHR and BAI did not correlate to fat percentage. Our results confirmed that CRP is a valuable marker of metabolic risk in obese females, and BMI, although not so new, is still reliable parameter of adiposity.Uvod/Cilj. Prekomerna telesna masa i gojaznost postali su značajan zdravstveni problem u razvijenim zemljama, a mogu biti povezani sa prisustvom hronične inflamacije niskog intenziteta u belom masnom tkivu. Cilj rada bio je da se ispitaju nivoi markera inflamacije, C-reaktivnog proteina (CRP), i njegova povezanost sa standardnim antropometrijskim parametrima kod predgojaznih i gojaznih žena. Metode. Studijom je bilo obuhvaćeno 200 zdravih žena (18-45 god) kojima su određeni standardni i alternativni antropometrijski parametari [indeks telesne mase (BMI), procenat masti (%F), obim struka (WC), odnos obima struka i kukova (WHR), odnos obima struka i visine (WHtR), kao i indeks telesne masnoće (BAI)] koji su zatim korelisani sa koncentracijama CRP u serumu. Rezultati. Prosečna vrednost nivoa CRP u serumu u celoj grupi iznosila je 5,56 ± 2,43 mg/L i utvrđena je njegova značajna pozitivna korelacija sa svim ispitivanim antropometrijskim parametrima. Uočena je statistički značajna razlika između grupa predgojaznih i gojaznih žena u svim ispitivanim antropometrijskim parametrima, kao i u pogledu koncentracije CRP. U grupi gojaznih ispitanica utvrđena je značajna povezanost između CRP i svih antropometrijskih parametara, dok u predgojaznoj grupi nije zabeležena statistička značajnost. U grupi gojaznih, svi antropometrijski pokazatelji pokazali su značajnu korelaciju sa procentom telesne masti, a kod predgojaznih žena, korelacija je bila značajna samo za telesnu masu, BMI, WC i WHtR. Zaključak. Između predgojaznih i gojaznih ispitanica postoji značajna razlika u pogledu svih pokazatelja centralne gojaznosti, kao i u pogledu koncentacije CRP u serumu. U grupi gojaznih, pokazana je značajna korelacija između sadržaja masti, izraženog kao procenat masnoće, i svih pokazatelja visceralne distribucije masti, dok u grupi predgojaznih značajna povezanost nije urađena za WHR i BAI. Naši rezultati potvrđuju da CRP može predstavljati značajan marker metaboličkog rizika kod gojaznih žena, kao i da je BMI, iako spada u tradicionalne parametre, i dalje pouzdan pokazatelj sadržaja telesne masti

Gene expression of chemokines CX3CL1 and CXCL16 and their receptors, CX3CR1 and CXCR6, in peripheral blood mononuclear cells of patients with relapsing-remitting multiple sclerosis - a pilot study

Background/Aim. In vitro and in vivo studies show that CX3CL1 and CXCL16 chemokines and their specific receptors, CX3CR1 and CXCR6, respectively, mediate mechanism of neuroinflammation during the pathogenesis of multiple sclerosis (MS). The aim of this study was to investigate relative messenger ribonucleic acid (mRNA) levels of CX3CL1, CXCL16, CX3CR1 and CXCR6 in peripheral blood mononuclear cells, as potential molecular markers of relapsing-remitting (RR) MS. Methods. The study included 43 unrelated RR MS patients, 20 of them with clinically active disease (relapse) and 23 with clinically stable disease (remission), and 28 unrelated healthy subjects as controls. Real-time polymerase chain reactions (PCR) were performed using TaqMan? gene expression assays. Relative expression (mRNA) level of each target gene in each sample of peripheral blood mononuclear cells was calculated as the mean normalized expression. Results. The levels of CX3CR1 mRNA were significantly higher in clinically active RR MS patients compared to controls [fold change = 1.38, p (Mann-Whitney U test) = 0.009], and significantly lower in clinically stable vs active RR MS patients [fold change = - 1.43, p (t-test) = 0.03]. Stable RR MS patients had significantly higher CXCL16 mRNA levels than controls [fold change = 1.33, p (Mann-Whitney U test) = 0.006]. A trend of increased CXCR6 gene expression was found in active RR MS patients compared to controls [fold change = 1.23, p (Mann-Whitney U test) = 0.08]. In either active or stable RR MS patients there were no significant correlations of the clinical parameters with expression levels of the target genes. Conclusion. The current results show that increased CX3CR1 mRNA levels in peripheral blood mononuclear cells could represent a proinflammatory molecular marker of clinically active RR MS

The association of ACE I/D gene polymorphism with severe carotid atherosclerosis in patients undergoing carotid endarterectomy

Introduction: The ACE I/D polymorphism was mostly investigated in association with intima-media thickness, rarely with severe atherosclerotic phenotype. Materials and methods: We investigated the association of I/D polymorphism with severe carotid atherosclerosis (CA) (stenosis GT 70%) in asymptomatic and symptomatic patients undergoing carotid endarterectomy. The 504 patients subjected to endarterectomy and 492 healthy controls from a population in Serbia were investigated as a case-control study. Results: The univariate logistic regression analysis revealed ACE DD as a significant risk factor for severe CA (odds ratio [OR] = 1.3, 95% confidence interval [CI] 1.0-1.7, p = 0.04). After adjustment for the common risk factors (age, hypertension, smoking, and HDL) ACE was no longer significant. However, we found a significant independent influence of DD genotype on plaque presence in a normotensive subgroup of patients (OR 1.8, CI 1.2-3.0, p = 0.01, corrected for multiple testing). In symptomatic patients D allele carriers were significantly more frequent compared with asymptomatic patients (OR 1.6 CI 1.0-2.6, p = 0.05). Conclusions: Our data suggests that ACE I/D is not an independent risk factor for severe CA. On the other hand, a significant independent genetic influence of ACE I/D appeared in normotensive and symptomatic patients with severe CA. This should be considered in further research toward resolving the complex genetic background of severe CA phenotype

Angiotensin II receptor type 2 (AT2R) -1332 A/G gene polymorphism as a risk factor for multiple sclerosis

Multiple sclerosis (MS) is a complex inflammatory,demyelinating disease of central nervous system (CNS). All the essen-tial components of the renin-angiotensin system (RAS) are presentedin the mammalian brain. The angiotensin II (Ang II), biologicallyactive octapeptide is not only a vasoconstrictor, but also a pro-inflam-matory factor. Many of the classical and of the hypothetical functionsof brain Ang II are mediated by stimulation of AT1 receptors (AT1R).Brain AT2 receptors (AT2R) are highly expressed during development.In the adults, AT2R are restricted to areas predominantly involved inthe process of sensory information. The AT2R1332 A/G polymorph-ism was proposed to influence AT2R protein expression, and is themost studied polymorphism in this gene, in other diseases. Recently,the striking appearance of the RAS in MS brain was described.However, the role of AT2R remains to be clarified. Thus, the aim ofour study was to establish if there is an association between AT2R1332 A/G gene polymorphism and predisposition of MS Methods:Subjected group consisted of 122 female and 70 malepatients with MS and 75 female and 50 male controls from populationof Serbia. Genotyping was done by PCR and restriction digestion withEcoRI enzyme.Results:The genotype and allele frequencies for AT2R1332A/Ggene polymorphism are analyzed separately in females and males,since this gene is located on X chromosome. We detected significantoverrepresentation of1332A/G AA genotype (OR 1.6, 95% CI:1.0–2.7, p<0.05) in female patients with MS compared to female controls.In hemizygous males we didn’t found any difference between patientsand controls.Conclusion:The role of RAS genes in MS was neglected untilrecently. Than, it was shown that the role of RAS in the CNS isbeyond the regulation of cardiovascular function. Until now AT2R(1332A/G) gene polymorphism was widely studied and associatedwith hypertension and other vascular disease. Until now, there wereno studies concerning role of Ang II receptor polymorphisms in MS.This study suggest possible role of AT2R in MS. Further studies areneeded to elucidate this result.ECTRIMS : The 26th Congress of the European Committee for Treatment and Research in Multiple Sclerosis : Book of abstract

Reverse order law for the Moore–Penrose inverse

In this paper we present new results related to the reverse order law for the Moore-Penrose inverse of operators on Hilbert spaces. Some finite dimensional results are extended to infinite dimensional settings