Role of counterions in the adsorption and micellization behavior of 1:1 ionic surfactants at fluid interfaces─demonstrated by the standard amphiphile system of alkali perfluoro-n-octanoates

In our latest communication, we proved experimentally that the ionic surfactant’s surface excess is exclusively determined by the size of the hydrated counterion.[Lunkenheimer, Langmuir, 2017, 33, 10216−1022410.1021/acs.langmuir.7b00786]. However, at this stage of research, we were unable to decide whether this does only hold for the two or three lightest ions of lithium, sodium, and potassium, respectively. Alternatively, we could also consider the surface excess of the heavier hydrated alkali ions of potassium, rubidium, and cesium, having practically identical ion size, as being determined by the cross-sectional area of the related anionic extended chain residue. The latter assumption has represented state of art. Searching for reliable experimental results on the effect of the heavier counterions on the boundary layer, we have extended investigations to the amphiphiles’ solutions of concentrations above the critical concentration of micelle formation (cmc).We provided evidence that the super-micellar solutions’ equilibrium surface tension will remain constant provided the required conditions are followed. The related σcmccmccmc+ > Na+ > K+ > (NH4)+ > Rb+ > Cs+. Therefore, we have to extend our model of counterion effectiveness put forward in our previous communication. It represents a general principle of the counterion effect

Обеспечение безопасности радиоактивных источников на гипотетическом объекте

Объектом исследования является вопросы организации и функционирования систем физической защиты, учета и контроля ядерных материалов. Целью работы является создание методического подхода для описания и построения гипотетического объекта и его систем безопасности, с дальнейшем его применением в учебных целях по специальности Безопасность и нераспространение ядерных материалов.The object of research is the organization and functioning of systems of physical protection, accounting and control of nuclear materials. The aim of the work is to create a methodological approach to the description and construction of a hypothetical object and its security systems, with its further application for educational purposes in the specialty safety and non-proliferation of nuclear materials

Photothermal treatment of cutaneous lesions

This thesis reviews the understanding of the processes involved in the laser treatment of cutaneous blemishes. The current treatment protocol for the treatment of vascular lesions - double scanning with transient blanching used at St George's Hospital is shown to give excellent results. The protocol takes advantage of the precise control provided by the SCANALL automatic scanner and the 5 W, 578 nm output of the copper vapour laser. The clinical endpoint - transient blanching - is shown to be due to a temporary halting of blood flow (probably by vasoconstriction) rather than coagulation necrosis of overlying tissues. Various models of the laser treatment of vascular lesions are presented and examined. A histological study of the double scanning, transient blanching protocol shows that tissue damage is confined to vascular and perivascular tissue. Cosmetic lightening is due to a reduction in both the number and size of the vessels in the upper dermis. The protocol is also investigated by interview and postal survey. The incidence of adverse effects is small. For example, there are only two 1 cm² adverse skin texture changes in 64000cm² of treated area. Patients receiving treatment for telangiectasia and spider naevus are satisfied with the outcome after one or two treatments, but many with port-wine stain cease treatment after four sessions when government funding runs out. Patient perception of the success is compared with the surgeon's perception. Patients often needed to be reminded of the size and severity of their original lesion with a photograph. The thesis reports on a parallel investigation of the use of millisecond scale pulses of white light for the treatment of tattoos. A xenon flash-lamp system is designed, constructed, and used in a clinical trial. This includes building pulse forming networks to produce rectangular current pulses of differing lengths. During the clinical trial the system produced a strong inflammatory response in the skin adjacent to the pigment, and lightening of the tattoo. Modelling, histology and other literature studies lead to the conclusion that the pulse length is too long to cause the explosive rupture of pigment-containing cells observed after Q-switched laser treatment, and too short to cause sufficient necrosis and phagocytosis of the pigment-containing cells for it to be useful clinically. The thesis also describes the construction of a device to measure muscle tension during tendon transfer surgery. The device uses diffraction to measure the separation of the fundamental unit of muscle tissue - the sarcomere

Low angular momentum flow model of Sgr A* activity

Sgr A* is the closest massive black hole and can be observed with the highest angular resolution. Nevertheless, our current understanding of the accretion process in this source is very poor. The inflow is almost certainly of low radiative efficiency and it is accompanied by a strong outflow and the flow is strongly variable but the details of the dynamics are unknown. Even the amount of angular momentum in the flow is an open question. Here we argue that low angular momentum scenario is better suited to explain the flow variability. We present a new hybrid model which describes such a flow and consists of an outer spherically symmetric Bondi flow and an inner axially symmetric flow described through MHD simulations. The assumed angular momentum of the matter is low, i.e. the corresponding circularization radius in the equatorial plane of the flow is just above the innermost stable circular orbit in pseudo-Newtonian potential. We compare the radiation spectrum from such a flow to the broad band observational data for Sgr A*.Comment: Proceedings of the AHAR 2008 Conference: The Universe under the Microscope; Astrophysics at High Angular Resolution, Bad Honef

Experimental investigation of the elasticity of the human diaphragm

<p>Abstract</p> <p>Background</p> <p>Traumatic diaphragmatic ruptures affect mainly the left side. In an experimental study in human corpses we examined the stretch behaviour of the left and right diaphragmatic halves.</p> <p>Methods</p> <p>In a total of 8 male and 8 female corpses each diaphragmatic half was divided into 4 different segments. Each segments stretch behaviour was investigated. In steps of 2 N the stretch was increased up to 24 N.</p> <p>Results</p> <p>In the female the left diaphragm showed a stronger elasticity compared to the right. Additionally the left diaphragm in females showed a higher elasticity in comparison to the left in males. Traumatic diaphragmatic ruptures affect mostly the central tendineous part or the junction between tendineous and muscular part of the diaphragmatic muscle. Accordingly we found a lower elasticity in these parts compared with the other diaphragmatic segments.</p> <p>Conclusion</p> <p>In summary it can be said that albeit some restrictions we were able to determine the elasticity of different diaphragmatic segments quantitatively and reproduceably with our presented method. Thereby a comparison of results of different diaphragmatic segments as well as of both diaphragmatic halves and of both genders was possible</p

Decreased endothelin receptor B expression in large primary uveal melanomas is associated with early clinical metastasis and short survival

The most devastating aspect of cancer is the metastasis of tumour cells to organs distant from the original tumour site. The major problem facing oncologists treating uveal melanoma, the most common cancer of the eye, is metastatic disease. To lower mortality, it is necessary to increase our understanding of the molecular genetic alterations involved in this process. Using suppression subtractive hybridisation, we have analysed differential gene expression between four primary tumours from patients who have developed clinical metastasis and four primary tumours from patients with no evidence of metastasis to date. We have identified endothelin receptor type B as differentially expressed between these tumours and confirmed this observation using comparative multiplex RT–PCR. In a further 33 tumours, reduced endothelin receptor type B expression correlated with death from metastatic disease. Reduced expression also correlated with other known prognostic indicators, including the presence of epithelioid cells, chromosome 3 allelic imbalance and chromosome 8q allelic imbalance. Endothelin receptor type B expression was also reduced in four out of four primary small cell lung carcinomas compared to normal bronchial epithelium. We also show that the observed down-regulation of endothelin receptor type B in uveal melanoma was not due to gene deletion. Our findings suggest a role for endothelin receptor type B in the metastasis of uveal melanoma and, potentially, in the metastasis of other neural crest tumours

Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form