Computer aided planning of WLAN access networks

An Internet application was developed to support the design process of the WLAN access network. The whole program was designed as a desktop application using the following languages: HTML, CSS and JavaScript. The main task of the application facilitates the planning process of the WLAN access network, including the location of multiple base stations.  There is an example of using the program in the WLAN network planning process. The main purpose of this application as the ability to carry out network planning using multiple base stations and provide radio coverage for the entire area served by Wireless Internet Service Provider, is obtained

Properties of a wireless mesh network constructed with the use of IQRF modules in the indoor environment

The subject of the article is the design and practical implementation of the wireless mesh network. IQRF radio modules were used for the network design. The IQRF® technique has enabled the construction of a mesh network with the possibility of reconfiguration. The theoretical part contains a description of the IQRF® hardware solutions used. The practical scope includes the design part, where the configuration of the radio modules was carried out and the parameters of the radio network were set to allow its implementation in various topologies. Then, a wireless network consisting of 10 IQRF modules was launched in the P3 building of the Opole University of Technology. At this stage, configured radio modules were placed in selected rooms on all five floors of the building in order to carry out tests of the radio network constructed in this way. The tests included measuring the packet transmission delay time as well as the received signal strength. Research was carried out for several network topologies

Metrological properties of the test setup for determination shielding effectiveness of the industrial cable connectors

The paper presents results related to assessment of the repeatability and reproducibility of the measurement test setup for determination the relative value of the shielding effectiveness coefficient of the industrial connectors. The constructio of the proposed test setup, the measurement method and the procedure for the analysis of measurement results were described. To determine the value of the repeatability and reproducibility coefficient, the two–way analysis of variance was used, which additionally allows for an assessment of the influence of individual sources of variance. The measurements and their analysis were conducted for several frequencies in the range up to 1 GHz. Additionally, the expanded measurement uncertainty, including the test setup and instruments uncertainty was estimated

The efficacy of radiofrequency catheter ablation in ectopic atrial tachycardia

Background: Ectopic atrial tachycardia (EAT) is a relatively rare form of supraventricular arrhythmia, which, if persistent, may lead to tachycardia-induced cardiomyopathy (TIC), associated with an equally poor prognosis, including the risk of sudden cardiac death, as other dilated cardiomyopathies. The aim of the study was to evaluate the efficacy and course of radiofrequency catheter ablation (RFCA) in the treatment of patients with EAT. Methods: The study group comprised 33 consecutive patients (16 males and 17 females of mean age 41 ± 15 years) managed for EAT at our clinic. Each patient underwent an electrophysiological study (EPS) and atrial mapping during an episode of arrhythmia using the CARTO system. Subsequent RFCA was undergone by 32 patients. The procedure was considered successful if the arrhythmia terminated during energy application and remained non-inducible by isoprenaline. The mean follow-up period was 23 ± 13 months.Results: The ectopic focus was localised in the right atrium in 29 patients (88%) and in the left atrium in 5 patients (15%). In 6 patients more than one ectopic focus was found. The mean duration of the procedure was 159 ± 67 min and the mean duration of fluoroscopy was 25 ± 15 min. In 32 patients undergoing RFCA for the first time (the first session), the efficacy was 97%. In 2 patients with a recurrence of tachycardia and in 3 patients with EAT caused by another ectopic focus a re-ablation was performed (the second session) with an efficacy of 80%. The patient in whom re-ablation was unsuccessful underwent a third RFCA (third session). The total efficacy was 97%. Conclusions: Radiofrequency catheter ablation is an effective and safe treatment in patients with ectopic atrial tachycardia

The comparison of contrast echocardiography and tissue Doppler imaging for evaluation of reperfused myocardium in patients with acute anterior myocardial infarction

Background: Prediction of functional myocardial recovery post acute myocardial infarction should be based not only on flow patency of the infarct related artery (IRA) but also on the quality of microcirculation in at-risk segments. Myocardial blush grade (MBG) is a method of perfusion assessment which has an established value in prediction of both ventricular remodelling and prognosis. However, its invasive character encourages the search for other methods able to reflect myocardial recovery following successful reperfusion. Echocardiography is an imaging modality which has the potential to assess, noninvasively, myocardial perfusion and, quantitatively, the loss of contractile function. The aim of this study was to compare the values of myocardial contrast echocardiography (MCE), MBG and tissue Doppler imaging (TDI) in the assessment of microcirculation in patients with first acute myocardial infarction of the anterior wall. Methods: The study group consisted of 39 patients (15 female and 24 male, mean age 58.8 ± 12.2 years) with first anterior infarction within 6 hours of chest pain onset. All patients underwent angioplasty of the anterior descending artery (LAD). Myocardial blush grade was assessed directly after angioplasty, whereas MCE using SonoView contrast accompanied by TDI study was performed 4 days thereafter. Results: Neither of the quantitative MCE parameters showed significant correlation with perfusion assessed by MBG. Significant negative correlation of MBG was found with maximal systolic strain ( e) (R = -0.51, p = 0.003) and post systolic shortening (R = -0.49, p = 0.007) in infarcted segments, but this was not the case with the unaffected segments. Conclusions: Use of MCE in the assessment of myocardial perfusion in myocardial infarction is limited, as shown by poor correlation with MBG. The presence of impaired contractile function by TDI corresponds better with myocardial perfusion than MCE does

Analysis of the cytotoxicity of carbon-based nanoparticles, diamond and graphite, in human glioblastoma and hepatoma cell lines

Nanoparticles have attracted a great deal of attention as carriers for drug delivery to cancer cells. However, reports on their potential cytotoxicity raise questions of their safety and this matter needs attentive consideration. In this paper, for the first time, the cytotoxic effects of two carbon based nanoparticles, diamond and graphite, on glioblastoma and hepatoma cells were compared. First, we confirmed previous results that diamond nanoparticles are practically nontoxic. Second, graphite nanoparticles exhibited a negative impact on glioblastoma, but not on hepatoma cells. The studied carbon nanoparticles could be a potentially useful tool for therapeutics delivery to the brain tissue with minimal side effects on the hepatocytes. Furthermore, we showed the influence of the nanoparticles on the stable, fluorescently labeled tumor cell lines and concluded that the labeled cells are suitable for drug cytotoxicity tests

Long-term outcomes of cardiac resynchronization therapy are worse in patients who require atrioventricular junction ablation for atrial fibrillation than in those with sinus rhythm

Background: The aim of the study was to assess the impact of atrial fibrillation (AF) with and without the need for atrioventricular junction (AVJ) ablation on outcomes in patients undergoing cardiac resynchronization therapy (CRT).Methods: A single center cohort of 200 consecutive CRT patients was divided into three groups: 1) AF with CRT pacing < 95% in which AVJ ablation was performed (AF-ABL, n = 40; 20%), 2) AF without the need for AVJ ablation (AF-non ABL, n = 40; 20%), 3) sinus rhythm (SR, n = 120; 60%). All patients were assessed before CRT implantation and at 6-month follow-up. Positive clinical response to CRT was considered alive status without the need for heart transplantation and improvement ≥ 1 NYHA after 6 months. The comparative analysis among all study groups with respect to response-rate and long-term survival was performed.Results: The 6-month response-rate in both AF-ABL and AF-nonABL was significantly lower than in SR (52.5 and 50 vs.77.5%, respectively; both p < 0.017), though there were no differences in baseline characteristics among study groups apart from higher baseline NT-proBNP levels in AF-ABL. However, after adjustment for this confounder, and despite optimal CRT pacing burden in study groups, the remote all-cause mortality during median follow-up of 36.1 months was significantly higher in AF-ABL than in SR (adjusted HR = 2.57, 95% CI 1.09–6.02, p = 0.03). What is more, no difference in long-term survival between SR and AF-nonABL was observed.Conclusions: Despite the improvement of CRT pacing burden and thus response-rate up to the level of AF subjects without the need for ablation, the long-term survival of AF patients requiring AVJ ablation remains still worse than in SR

Atrial fibrillation in patient with concealed Wolff-Parkinson-White syndrome

 We present a case of 33-year-old woman suffered from palpitations and syncope. ECG was normal at the rest and showed irregular tachycardia with wide QRS complex (HR > 300/min) during the effort. The patient was admitted to our department in order to perform detailed diagnostics and therapy. Based on electrophysiological study we found and ablated numerous concealed accessory pathways. During 1 year observation patient stay assymptomatic

A comparison of the clinical course of preexcitation syndrome in children and adolescents and in adults

Background: Atrioventricular reentrant tachycardia (AVRT) in patients with preexcitation syndrome (PS) is the main cause of paroxysmal regular arrhythmias in children and adolescents. While the previously published data most commonly concern clinical consequences of PS in adults, few researchers have evaluated the problem in children and adolescents. The aim of the study was to compare the clinical course of PS between the population of children and adolescents below 19 years of age and the population of adult patients. Method: The study population consisted of 302 consecutive PS patients managed between January 2001 and June 2005 with radiofrequency catheter ablation (RFCA). The study population was divided into two groups: Group 1 consisting of 52 patients aged 15.38 years on average (7-18 &#177; 2.53) and Group 2 consisting of 250 adult patients aged 38.67 years on average (19-72 &#177; 13.1). Results: Patients from Groups 1 and 2 experienced their first episode of AVRT at the mean age of 13.3 years and 29.1 years, respectively (p < 0.05). The mean annual numbers of AVRT episodes in Groups 1 and 2 were 12.97 (range, 2-96; median, 8) and 8.86 (range, 2-25; median, 6), respectively (p = non-significant). Two patients from Group 1 (3.85%) and 42 patients from Group 2 (16.8%) experienced episodes of atrial fibrillation (AF) (p < 0.05). Location of the accessory pathways (AP): In Group 1, the right free wall and anteroseptal AP locations were significantly more common [11 (21.15%) and 9 (17.31%) patients, respectively, vs.q 19 (7.6%) and 13 (5.2%) patients in Group 2; p < 0.01]. In Group 2, the left anterolateral AP location was more common [81 (32.4%) vs. 4 (7.69%) in Group 1; p < 0.01]. Conclusions: In children and adolescents with PS, a significantly lower incidence of AF was found. In Group 1, RFCA was performed significantly more frequently due to the development of AVRT caused by right free wall and right anteroseptal AP, while in the group of adults, the left anterolateral AP location was found more commonly. (Cardiol J 2007; 14: 384-390

Porównanie metod echokardiografii kontrastowej oraz doplera tkankowego w ocenie reperfuzji mięśnia sercowego u pacjentów z ostrym zawałem serca

Wstęp: Przewidywania dotyczące powrotu do normy funkcji mięśnia sercowego po ostrym zawale serca powinny się opierać nie tylko na stopniu uzyskanej drożności tętnicy odpowiedzialnej za zawał (IRA), ale także na ocenie jakości mikrokrążenia w strefie segmentów objętych ryzykiem niedokrwienia. Metodą, która ma ugruntowaną wartość w zakresie rokowania i przewidywania procesów remodelingu komór, jest tak zwana skala MBG. Jednak inwazyjny charakter tej techniki zachęca do poszukiwania innych metod mogących ocenić powrót czynności mięśnia sercowego po zabiegu skutecznej reperfuzji. Echokardiografia jest techniką obrazową pozwalającą na potencjalnie nieinwazyjne określenie perfuzji mięśnia sercowego oraz ilościową ocenę utraty funkcji skurczowej serca. Celem niniejszej pracy było porównanie wartości obrazowania mięśnia sercowego za pomocą echokardiografii kontrastowej (MCE), metody MBG oraz echokardiograficznego doplera tkankowego (TDI) w zakresie oceny mikrokrążenia u pacjentów po pierwszym w życiu ostrym zawale przedniej ściany serca. Metody: Grupa badawcza składała się z 39 pacjentów (15 kobiet i 24 mężczyzn, średni wiek 58,8 &#177; 12,2 roku) z pierwszym w życiu ostrym zawałem przedniej ściany serca przyjętych do szpitala w ciągu 6 godzin od początku bólu. Wszystkich chorych poddano angioplastyce wieńcowej w zakresie gałęzi przedniej zstępującej lewej tętnicy wieńcowej (LAD). Oceny mikrokrążenia za pomocą skali MBG dokonywano bezpośrednio po zabiegu angioplastyki wieńcowej, natomiast oceny przy zastosowaniu metod MCE (kontrast SonoView) oraz TDI - 4 dni później. Wyniki: Żaden z ilościowych parametrów metody MCE nie wykazał istotnej korelacji z parametrami perfuzji uwidocznionej w skali MBG. W odniesieniu do segmentów mięśnia sercowego dotkniętych zawałem stwierdzono istotną ujemną korelację wartości skali MBG z maksymalnym skurczowym odkształceniem miokardium (e) (R = &#8211;0,51; p = 0,003) oraz ze skróceniem poskurczowym (R = &#8211;0,49; p = 0,007), przy czym zależności takich nie stwierdzono w obrębie segmentów nieobjętych niedokrwieniem. Wnioski: Zastosowanie metod echokardiografii kontrastowej w ocenie perfuzji mięśnia sercowego w przebiegu zawału serca ma ograniczone zastosowanie, na co wskazuje słaba korelacja parametrów MCE z oceną metodą MBG. Stwierdzenie upośledzenia regionalnej funkcji kurczliwej mięśnia sercowego za pomocą TDI lepiej odzwierciedla zaburzenia perfuzji serca niż stosowane metody echokardiografii kontrastowej