The influence of Si/Al ratio on the distribution of OH groups in zeolites with MWW topology

A series of MWW-type zeolites of increasing Si/Al ratio were investigated with respect to their acidic properties. Concentration of the Brønsted acid centers located at the external crystal surface was invariant for the entire series. Ethanol conversion to ethyl-tert-butyl ether, proceeding only at the external surface, was also constant. The OH groups in MWW zeolites were found to be homogeneous with proton affinity value equal to 1142.7 kJ/mol

Sol-gel synthesis of iron oxide-silica composite microstructures

Spherical silica particles doped with iron oxide have been synthesized via base-catalyzed one-pot sol–gel process using tetraethoxysilane (TEOS) and iron(III) eth- oxide (ITE) as co-precursors. In the modified Sto ̈ ber pro- cess adopted, depending on the concentration of ITE in the starting composition, materials of various morphologies were observed under a scanning electron microscope and an atomic force microscope. The presence of ITE signifi- cantly affected the formation process of particulate silica; the spherical particles were formed accompanied by the co- presence of irregular-shaped finer aggregates. The fraction of the aggregates with rough surfaces increased with an increase of the ITE content in the reaction mixture. Both the spherical particles and irregular-shaped aggregates contained iron hydroxide and they exhibited paramagnetic behavior. The chemical composition and physicochemical properties of the materials were determined using various complementary spectroscopic methods

A novel system for patient ventilation and dosing of hyperpolarized ^{3}He for magnetic resonance imaging of human lungs

A versatile ventilator for controlling a patient’s breath cycle and dosing 3He gas has been designed and constructed. It is compatible with a medical magnetic resonance imaging scanner and can be incorporated into routine human lungs imaging procedure that employs hyperpolarized noble gas as a contrast agent. The system adapts to the patient’s lung volume and their breath cycle rhythm, providing maximum achievable comfort during the medical examination. Good quality magnetic resonance lung images of healthy volunteers were obtained. The system has the capability of recycling the exhaled gas to recover the expensive 3He isotope, and can be also adapted to human lung imaging with hyperpolarized 129Xe

Wpływ niewielkiego i zaawansowanego niedokrwienia na przepływ w mikrokrążeniu skórnym u pacjentów z miażdżycowym niedokrwieniem kończyn dolnych

Introduction. The aim of the study was to characterize the changes in the microcirculation in patients with varying severity of atherosclerotic ischaemia of the lower limbs (PAOD). Material and methods. The study included 27 healthy subjects, 79 patients with PAOD category 0 and 1 according to the Rutherford classification, and 137 patients with PAOD category 3 and 4. The study evaluated cutaneous blood flow, flowmotion bonds, percutaneous partial pressure of oxygen and flow-mediated vasodilation. Results. Even mild PAOD exhibits a worse systemic vascular function expressed as a reduction in the scope of flow-mediated vasodilation, and locally in TcpO2 decrease. Increase in local changes in advanced forms of PAOD were observed as further reduction in TcpO2 and a drastic reduction or exhaustion of the functional microcirculatory reserve. Among the evaluated risk factors for atherosclerosis only diabetes and smoking significantly modified perfusion, which resulted in a significant decrease in the values of vasodilation and TcpO2. Conclusions. The study revealed the occurrence of adverse changes in microcirculation, also in patients with poorly discernible signs of limb ischaemia. It can be assumed that these may also occur in the patients who underwent a haemodynamically effective revascularization.Wstęp. Celem badań było scharakteryzowanie zmian w mikrokrążeniu u pacjentów z różnym stopniem zaawansowania miażdżycowego niedokrwienia kończyn dolnych (PAOD). Materiał i metody. Do badania włączono 27 zdrowych osób, 79 pacjentów z PAOD w 0 i 1 kategorii oraz 137 pacjentów z PAOD w 3 i 4 kategorii według klasyfikacji Rutherforda. Oceniano skórny przepływ krwi, pasma flowmotion, przezskórne ciśnienie parcjalne tlenu i wazodylatację indukowaną przepływem. Wyniki. Już w łagodnej postaci PAOD występuje ogólnoustrojowe pogorszenie funkcji naczyń, wyrażone zmniejszeniem zakresu wazodylatacji indukowanej przepływem, a miejscowo zmniejszeniem TcpO2. W zaawansowanych postaciach PAOD obserwowano pogłębienie zmian miejscowych w postaci dalszego obniże­nia TcpO2 i radykalnego zmniejszenia lub też wyczerpania rezerwy czynnościowej mikrokrążenia. Spośród ocenianych czynników ryzyka rozwoju miażdżycy tylko cukrzyca i palenie tytoniu znamiennie modyfikowały perfuzję, istotnie zmniejszając wartości wazodylatacji i TcpO2. Wnioski. W przeprowadzonym badaniu wykazano występowanie niekorzystnych zmian w mikrokrążeniu także u pacjentów ze słabo zaznaczonymi objawami niedokrwienia kończyn. Można przypuszczać, że mogą one występować również u pacjentów po skutecznych hemodynamicznie zabiegach rewaskularyzacji

In vitro antileukemic activity of novel adenosine derivatives bearing boron cluster modification

A series of adenosine derivatives bearing a boron cluster were synthesized and evaluated for their cytotoxicity against primary peripheral mononuclear cells from the blood of 17 patients with leukemias (16 CLL and 1 very rare PLL), as well as from 5 healthy donors used as a control. Among the tested agents, two, i.e., compounds 1 and 2, displayed high in vitro cytotoxicity and proapoptotic potential on leukemic cells, with only scarce activity being seen against control cells. Biological tests related to apoptosis revealed the activation of the main execution apoptotic enzyme, procaspase-3, in CLL and PLL cells exposed to compounds 1 and 2. Moreover, the above compounds indicated high activity in the proteolysis of the apoptotic markers PARP-1 and lamin B1, fragmentation of DNA, and the induction of some changes in the expression of the Mcl-1, protein apoptosis regulator in comparison with control cells