Effect of adenosine on myocardial protection increased exercise tolerance and decrease the frequency of angina in elderly patients with chronic total occlusion of coronary arteries

It were investigated the effects of adenosine on the cases of myonecrosis after non-urgent percutaneous coronary intervention (PCI). This was a prospective, randomized, open-label study. Patients who were scheduled for non-urgent PCI were eligible. All patients were pretreated with aspirin and clopidogrel. Myonecrosis was measured by creatine kinase-myocardial band (CK-MB) and troponins elevation after PCI. A total of 49 patients were randomized into two groups: the adenosine (n = 39) and standard (n = 30) group. The adenosine group received 10 mg adenosine bolus before wiring of each lesion, whereas the standard group did not. Pretreatment with 10 mg of adenosine a decreases the incidence of myonecrosis after undergoing percutaneous coronary intervention and restoration of exercise endurance, save the patients from having anginal attacks of a chronic total occlusion in coronary arteries comparing with that without pretreatment.Изучено влияние интракоронарного введения триггера ишемического прекондиционирования (ИП) аденозина на снижение частоты развития ассоциированного с чрескожными коронарными вмешательствами (ЧКВ) инфаркта миокарда (ИМ), толерантностть к физической нагрузке (ТФН), частоту ангинозных приступов у пожилых больных при проведении операций реканализации хронических окклюзий коронарных артерий (ХОКА). Пациенты разделены на две группы: I группа - интракоронарное введение 10 мг аденозина перед ЧКВ (п=39) и II группа - пациенты, которым ЧКВ проводили без введения аденозина (п=30). Определяли тропонин I (Тн I), MB фракцию креатинфосфокиназы (МВ-КФК) за 1 час до ЧКВ, через 18-24 часа и на 5-е сутки после ЧКВ. Оценивали частоту развития ассоциированного с ЧКВ инфаркта миокарда (ИМ) согласно критериям ESC/ACCF/AHA/WHF (2007), необходимости в повторном чрескожном коронарном вмешательстве (ЧКВ) и экстренной операции аортокоронарного шунтирования (АКШ) в госпитальном периоде, через 12 месяцев и 3 года. С целью оценки влияния интракоронарного введения аденозина на толерантность к физической нагрузке оценивали пороговую мощность нагрузки (ПМ), продолжительность физической нагрузки (ПН), двойное произведение (ДП), и частоту приступов стенокардии в сутки через 24 часа, месяц и 12 месяцев и 3 года после операции. Интракоронарное ведение триггера ишемического прекондиционирования аденозина снижает частоту развития периоперационной ишемии и ассоциированного с ЧКВ инфаркта миокарда, что приводит к статистически достоверному повышению толерантности к физической нагрузке, продолжительности физической нагрузке, двойного произведения и значительно снижает частоту приступов стенокардии в сравнении с контрольной группой

Microstructural evolution in solution heat treatment of gas- atomised Al alloy (7075) powder for cold spray

Cold gas dynamic spray is being explored as a repair technique for high-value metallic components, given its potential to produce pore and oxide-free deposits of between several micrometers and several millimeters thick with good levels of adhesion and mechanical strength. However, feedstock powders for cold spray experience rapid solidification if manufactured by gas atomization and hence can exhibit non-equilibrium microstructures and localized segregation of alloying elements. Here, we used sealed quartz tube solution heat treatment of a precipitation hardenable 7075 aluminum alloy feedstock to yield a consistent and homogeneous powder phase composition and microstructure prior to cold spraying, aiming for a more controllable heat treatment response of the cold spray deposits. It was shown that the dendritic microstructure and solute segregation in the gas-atomized powders were altered, such that the heat-treated powder exhibits a homogeneous distribution of solute atoms. Micro-indentation testing revealed that the heat-treated powder exhibited a mean hardness decrease of nearly 25% compared to the as received powder. Deformation of the powder particles was enhanced by heat treatment, resulting in an improved coating with higher thickness (* 300 lm compared to * 40 um for untreated feedstock). Improved particle–substrate bonding was evidenced by formation of jets at the particle boundaries

Non-destructive residual stress investigations of natural polycrystalline diamonds

Three natural polycrystalline diamond samples have been investigated non-destructively in their raw as-discovered forms. The samples originate from different locations in the world and possibly have different mechanisms of formation. The study reveals that the stones are primarily composed of cubic diamond with varying amounts of impurities that emanate from their excessive porosities and entrapped environmental contamination, contributed by the areas in which they were formed and subsequently discovered. Residual stress analyses of the cubic diamond phase with Xray and neutron diffraction techniques revealed low stress values in the interior regions of the diamonds.6 page(s