92 research outputs found
Short and long term outcomes of primary angioplasty in patients aged 75 years and over
The treatment of elderly patients with ST segment elevated myocardial infarction (STEMI) remains controversial. This study aimed to investigate the effects of primary angioplasty in elderly patients on in-hospital and long term major adverse cardiac events (MACE).Materials and methods: From October 2003 to March 2008, we retrospectively enrolled 220 patients aged 75 years and over with STEMI who underwent primary angioplasty. Patients’ characteristics, in-hospital and long term events were recorded.Results: Male/Female ratio of patients was 129/91 and mean age was 78.7 ± 3.6 (range, 75-97) years, and 58.6% of male). Of these patients 29.2% were diabetics, 69.8% were hypertensive, 34.4% were smoker and 43.5% were anemic at admission. Anterior myocardial infarction was diagnosed in 52.3% of patients. Mean pain-balloon time was 222 ± 116 minutes. Eighty two (38.2%) of these 220 patients had three-vessel disease and 12 (5.7%) were diagnosed as cardiogenic shock. Procedural success was observed in 79.6% of patients. Heart failure was observed 27.7% in hospital and intra aortic pump was used in 14.5% of patients. There was no significant difference between age groups in long term major cardiac events and in hospital mortality. Diabetes, leukocyte count at admission and in hospital heart failure were independent predictors of short term MACE and low hemoglobin level at admission and peak CKMB levels were independent predictors of long term MACE.Conclusions: Primary angioplasty in patients aged 75 years and over seems to be associated with low procedural complication, high procedural success, improved short and long term survival
Bragg gratings inscription using PMMA polymer optical fibers drawn from preforms with specific thermal pre-treatment
In this work, fiber Bragg gratings (FBGs) are inscribed in various undoped poly(methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and inscription time and their temperature and strain sensitivities are investigated. The polymer optical fiber Bragg gratings (POFBGs) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. The PMMA POFs drawn from a preform without specific thermal pre-treatment need more inscription time than the fibers drawn from a preform that has been pre-annealed at 80ºC for 2 weeks. Using both UV lasers, for the latter fiber less than half the inscription time is needed compared with a commercial undoped PMMA POF and other homemade POFs, where the preforms have not had a well-defined thermal pre-treatment. The effect on a POF from a preform that has been annealed prior to drawing is different as previously shown in the literature, where these POFs are much less sensitive to thermal treatment. Also, a proper polymerization process plays a key role as will be discussed. These results indicate the impact of preform thermal pre-treatment as well as polymerization process before the PMMA POFs drawing, which can be an essential characteristic in view of developing POF sensors technology
Analysis of the process leading to termination of pregnancy in the third trimester
Objective: To evaluate fetal anomalies and processes leading to termination of pregnancy in the third trimester. Methods: The study includes all cases who underwent termination of pregnancy after 28 weeks of gestation due to fetal anomalies between 2017 and 2022. Results: Forty four of third trimester terminations were carried out in our clinic due to fetal anomalies incompatible with life or associated with severe sequelae. Structural anomalies including 35 (79.5%) cases were the most common reason of terminations followed by chromosomal or genetic abnormalities in 8 (18.2%) cases and intrauterine cytomegalovirus infection in 1 (2.3%) case. The processes leading to the third trimester termination were evaluated by dividing 44 patients into 5 groups. (1) Delayed diagnosis due to inadequate prenatal care (25 patients, 56.8%); (2) patients diagnosed with late-onset findings (5 patients, 11.4%); (3) patients with abnormal findings in prenatal care or history but delayed diagnosis (5 patients, 11.4%); (4) patients with abnormal findings requiring further evaluation (4 patients, 9.0%); (5) patients with a definitive diagnosis but latency in the decision of family for termination of pregnancy (5 patients, 11.4%). Conclusion: Termination of pregnancy in the third trimester has an important role in countries where unfollowed pregnancies are common and access to health services is poor due to low socio-economic status
Fast bragg grating inscription in PMMA polymer optical fibres:impact of thermal pre-treatment of preforms
In this work, fibre Bragg gratings (FBGs) were inscribed in two different undoped poly- (methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. Two PMMA POFs are used in which the primary and secondary preforms (during the two-step drawing process) have a different thermal treatment. The PMMA POFs drawn in which the primary or secondary preform is not specifically pre-treated need longer inscription time than the fibres drawn where both preforms have been pre-annealed at 80 °C for 2 weeks. Using both UV lasers, for the latter fibre much less inscription time is needed compared to another homemade POF. The properties of a POF fabricated with both preforms thermally well annealed are different from those in which just one preform step process is thermally treated, with the first POFs being much less sensitive to thermal treatment. The influence of annealing on the strain and temperature sensitivities of the fibres prior to FBG inscription is also discussed, where it is observed that the fibre produced from a two-step drawing process with well-defined pre-annealing of both preforms did not produce any significant difference in sensitivity. The results indicate the impact of preform thermal pre-treatment before the PMMA POFs drawing, which can be an essential characteristic in the view of developing POF sensors technology
Ion-Pairing Limits Crystal Growth in Metal-Oxygen Batteries
Aprotic alkali metal-oxygen batteries are widely considered to be promising
high specific energy alternatives to Li-ion batteries. The growth and
dissolution of alkali metal oxides such as Li2O2 in Li-O2 batteries and NaO2
and KO2 in Na- and K-O2 batteries, respectively, is central to the discharge
and charge processes in these batteries. However, crystal growth and
dissolution of the discharge products, especially in aprotic electrolytes, is
poorly understood. In this work, we chose the growth of NaO2 in Na-O2 batteries
as a model system and show that there is a strong correlation between the
electrolyte salt concentration and the NaO2 crystal size. With a combination of
experiments and theory, we argue that the correlation is a direct manifestation
of the strong cation-anion interactions leading to decreased crystal growth
rate at high salt concentrations. Further, we propose and experimentally
demonstrate that cation-coordinating crown molecules are suitable
electrochemically stable electrolyte additives that weaken ion-pairing and
enhance discharge capacities in metal-oxygen batteries while not negatively
affecting their rechargeability.Comment: 13 Pages, 4 Figures, 14 pages of Supplementary Informatio
Electromagnetic Compatibility (EMC) Evaluation of a Prototype Solar-Charged Electric Race-Car
This technical report presents and analyses measured results of the electromagnetic compatibility (EMC) profile of a prototype solar-charged electric race-car during driving and charging conditions. Laboratory measurements and setups were based on CISPR 12 and IEC 61851-21-1 automotive EMC standards and on non-legislative exploratory EMC test methodologies, developed by the EC’s JRC. Results and main findings of more than 100 different setups managed on VeLA 9 validated automotive EMC semi-anechoic chamber, are methodologically extracted from measured data and analysed. The basis of this scientific activity was established to fulfil the objectives of the Interoperability and Electromagnetic Compatibility of Electric Vehicles and their Charging Infrastructure Work Package (WPK INTEC 6311) under the INTEROP-STORE Project (PRJ 208), in collaboration with Bochum University of Applied Sciences, Germany.JRC.C.4-Sustainable Transpor
The effect of local corticosteroid injection on F-wave conduction velocity and sympathetic skin response in carpal tunnel syndrome
The aim of this study was to evaluate the efficacy of steroid injection for the treatment of the carpal tunnel syndrome (CTS), with F-wave parameters and sympathetic skin response (SSR). Seventeen hands of 10 women patients were treated with local steroid injection with 2-month follow-up. All patients underwent single injection into the carpal tunnel. Response to injection was measured nerve conduction studies (NCSs), median nerve F waves, and SSR before and after treatment. To determine the normal values, 42 hands of 21 healthy women were also studied. There was a significant improvement of sensory and motor nerve conduction values when compared to baseline values (P < 0.01). At the end of follow-up period, the median sensory distal latency and the sensory latency differences between the median and the ulnar nerve were improved 35 and 65%, respectively. The maximum, mean F-wave amplitudes and chronodispersion showed a slight improvement with respect to baseline values and controls, but statistical significance was not achieved after treatment. Although no statistically significant improvements were observed in SSR parameters, slightly decreased amplitudes and increased habituation of SSR were noted at the end of the treatment. The present study shows that the local steroid injection results in improvement in NCSs values, but the F-wave parameters were not effectual in short-term outcome of CTS treatment. These findings suggest that the sensory latency differences between the median and the ulnar wrist-to-digit 4 are better parameters in the median nerve recovery after treatment than the median sensory distal latency. Furthermore, the SSR does not seem to be a sensitive method in follow-up of CTS treatment
Eş eksenli elektrotlar ile magnezyum üretimi.
Main reason for the current losses in electrolytic magnesium production is the reaction between electrode products. Present study was devoted to effective separation of chlorine gas from the electrolysis environment by a new cell design and thus reducing the extent of back reaction between magnesium and chlorine to decrease energy consumption values. The new cell design was tested by changing temperature, cathode surface, current density, anode cathode distance and electrolyte composition. Both the voltages and the current efficiencies were considered to be influenced by the amount and hydrodynamics of chlorine bubbles in inter-electrode region. Cell voltages were also found to be affected from the nucleation of magnesium droplets and changes in electrolyte composition that took place during the electrolysis. A hydrodynamic model was used to calculate net cell voltage by including the resistance of chlorine bubbles on anode surface to theoretical decomposition voltage during electrolysis. Good correlations were obtained between experimental and calculated voltages. The same model was used to calculate current efficiencies by considering chlorine diffusion from bubble surfaces. A general agreement was obtained between calculated and experimental current efficiencies. Desired magnesium deposition morphology and detachment characteristics from cathode were obtained when MgCl2-NaCl-KCl-CaCl2 electrolytes were employed. Current efficiencies higher than 90% could be achieved using the above electrolyte. The cell consumes around 8 kWhkg-1 Mg at 0.43 Acm-2 as a result of high chlorine removal efficiency and capability of working at low inter-electrode distances. Furthermore, the cell was capable of producing magnesium with less than the lowest energy consumption industrially obtained, at about double the commonly practiced industrial current density levels.Ph.D. - Doctoral Progra
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