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A method for preparing ultrathin sections (- 20 nm) of inorganic solids has been developed using ultramicrotomy of resin-embedded crystal fragments. Undamaged crystals, oriented along a crystallographic direction, could be imaged with transmission electron microscopy (TEM) at a resolution better than 0.5 nm. The true internal structure of the crystals could be investigated by imaging the second in
Vitamin C is one of the most effective natural antioxidants. However, due to its poor solubility in non-aqueous environments, its use is restricted to water-based systems. In order to extend its advantages to lipophilic media, vitamin C must be converted into amphiphilic derivatives. Two new vitamin C-based surfactants were synthesized: a bolaform derivative (1,12-diascorbyl dodecanedioate, BOLA12
Mesoporous silica can be formed with amphiphilic molecules acting as structure-directing templates in dilute systems. The templating properties of five related triblock copolymers, (EO)x-(PO)y-(EO)x (Pluronic L101, P103, P104, P105, and F108), have been investigated regarding the length of the EO blocks as well as the temperature of the synthesis. It was found that the number of EO units is essent
Acute hemorrhage is a leading cause of death in trauma, and women are more susceptible to hypovolemic circulatory stress than men. The mechanisms underlying the susceptibility are not clear, however. The aim of the present study was to examine the compensatory mechanisms to defend central blood volume during experimental hypovolemia in women and men. Twenty-two women (23.1 +/- 0.4 yr) and 16 men (
Diabetes mellitus is associated with decreased haemodynamic stability and reduced tolerance to hypovolaemia. Compensatory haemodynamic responses during experimental hypovolaemia in type 1 diabetes patients with (DMR+) and without (DMR-) retinopathy as well as healthy controls (C) were studied. Lower body negative pressure created hypovolaemic circulatory stress. Volumetric techniques were used to
The cardiovascular regulation in humans depends to a major extent on sympathetic reflexes originating from volume receptors in the arterial as well as the cardiopulmonary region. With experimental approaches, such as lower body negative pressure (LBNP) and tilting, signs of reduced efficiency with ageing have been shown. However, a confounding factor may be an age-related decline in venous capacit
AIMS/HYPOTHESIS: Patients with Type I (insulin-dependent) diabetes mellitus have a reduced transcapillary fluid absorption from skeletal muscle and skin and thus defective plasma volume regulation during hypovolaemia. Our aim was to find whether a defective capillary filtration coefficient or impaired transcapillary driving force are aetiologic factors for this reduction.METHODS: We investigated 1
OBJECTIVES: Diabetes mellitus is associated with a high cardiovascular morbidity which has been linked to disturbances in microvascular function. This study was designed to examine the transcapillary fluid absorption during experimental hypovolaemia in type 1 diabetes.SUBJECTS: Twelve males with type 1 diabetes (age 25 +/- 3 years, duration 8 +/- 1 years) with no clinical microangiopathy and 12 he
Venous compliance in the calf of humans and its importance for capacitance function in relation to age were studied with the aid of 22, 44, and 59 mmHg lower body negative pressure (LBNP). Negative pressure transmission to the calf as well as changes in calf volume were studied, and venous compliance was calculated [change in volume with pressure change (dV/dP)]. The change in capacitance response
Venous compliance in the legs of aging man has been found to be reduced with decreased blood pooling (capacitance response) in dependent regions, and this might lead to misinterpretations of age-related changes in baroreceptor function during orthostasis. The hemodynamic response to hypovolemic circulatory stress was studied with the aid of lower-body negative pressure (LBNP) of 60 cmH(2)O in 33 h
This work presents a method for information fusion in source localization applications. The method utilizes the concept of optimal mass transport in order to construct estimates of the spatial spectrum using a convex barycenter formulation. We introduce an entropy regularization term to the convex objective, which allows for low-complexity iterations of the solu- tion algorithm and thus makes the
AIMS: To evaluate the effect of adding insulin to sulphonylurea (SU) and the effect of SU withdrawal on glycaemic control in Type 2 diabetic patients who failed on treatment with SU alone.METHOD: One hundred and seventy-five patients were included in a placebo-controlled multicentre study. During phase I (4 months), premixed insulin was added to glibenclamide therapy; during phase II (1-4 months,
The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument onboard the Rosetta spacecraft has measured molecular oxygen (O 2 ) in the coma of comet 67P/Churyumov-Gerasimenko (67P/C-G) in surprisingly high abundances. These measurements mark the first unequivocal detection of O 2 in a cometary environment. The large relative abundance of O 2 in 67P/C-G despite its high react
The origin of cometary volatiles remains a major open question in planetary science. Comets may have either agglomerated from crystalline ices condensed in the protosolar nebula (PSN) or from amorphous ice originating from the molecular cloud and interstellar medium. Here, based on the recent argon, krypton, and xenon measurements performed by the ROSINA mass spectrometer on board the European Spa
Radiolytic production has been proposed as a potential source for the molecular oxygen observed in comet 67P/Churyumov-Gerasimenko. Radiolysis can be exogenic or endogenic, the latter due to radionuclides present in the dust constitutive of the comet nucleus. We investigated the possibility of forming a significant amount of molecular oxygen through endogenic radiolysis. We applied a model of radi
The four massive Galilean satellites are believed to have formed within a circumplanetary disk during the last stages of Jupiter's formation. While the existence of a circum-Jovian disk is supported by hydrodynamic simulations, no consensus exists regarding the origin and delivery mechanisms of the building blocks of the forming satellites. The opening of a gap in the circumsolar disk would have e
Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with a mean abundance of 3.80 ±0.85% by the ROSINA mass spectrometer on board the Rosetta spacecraft. To account for the presence of this species in comet 67P/Churyumov-Gerasimenko, it has been shown that the radiolysis of ice grain precursors of comets is a viable mechanism in low-density environments, such as molec
