1,506 research outputs found
Differenzialdiagnose Nausea und Erbrechen
Zusammenfassung: Nausea und Erbrechen sind häufig. Sie können eine physiologische Antwort auf ein exogenes Toxin sein, aber auch Ausdruck einer organischen, psychischen oder funktionellen Erkrankung. Trotz der Fülle der Differenzialdiagnose gelingt es meist durch sorgfältige Anamnese und wenige Untersuchungen, den Auslöser zu finden. Die Ursachen akuter Beschwerden unterscheiden sich teilweise von denen chronischer. Bei Frauen im gebärfähigen Alter ist eine Schwangerschaft auszuschließen. Eine symptomatische Therapie kann bereits zu Beginn eingeleitet werden. Die Klärung chronischer Ursachen ist schwieriger. Funktionstests wie die Messung der Magenentleerung ergänzen die Diagnostik. Sie sollen nur in spezialisierten Zentren mit entsprechender Erfahrung durchgeführt werden. Ruminieren und Regurgitation sind von Erbrechen abzugrenzen. Findet sich keine Ursache für die Beschwerden, kann von einer funktionellen Erkrankung ausgegangen werde
Novel structural features of the ripple phase of phospholipids
We have calculated the electron density maps of the ripple phase of
dimyristoylphosphatidylcholine (DMPC) and palmitoyl-oleoyl phosphatidylcholine
(POPC) multibilayers at different temperatures and fixed relative humidity. Our
analysis establishes, for the first time, the existence of an average tilt of
the hydrocarbon chains of the lipid molecules along the direction of the ripple
wave vector, which we believe is responsible for the occurrence of asymmetric
ripples in these systems
Emerging trends for urban freight transport-The potential for sustainable micromobility
Aim
Active transportation referring to non-motorized modes of transport is promoted and popularized both in practice and in the scientific literature, while their use for urban freight transport has been largely neglected. Thus the main scope of the paper is to indicate the development potential of micromobility use in urban freight transport and to check its influence on urban sustainability.
Methods
The authors have hypothesized that active means of transport, with a focus on micromobility, have great development potential in freight transportation in cities. The implemented methods for analyzing the relationship between users’ characteristics, micromobility, and its impact on urban sustainable development, were logit and probit modelling. The authors’ system includes an analysis of factors connected with the topics of sustainability and micromobilty, that have met an essential scientific gap that this paper addresses.
Logistic (logit) regression is used mainly for binary, ordinal, and multi-level outcomes to find the probability of success (i.e. occurrence of some event). Probit regression, however, is primarily used in binary response models and assumes the normal distribution of data.
Results
The main finding of the article has led the authors to the statement that active means of transport, including micromobility have great development potential in freight transportation in cities.
Conclusions
Knowledge of the acceptance of micromobility solutions is essential for municipal authorities in shaping the development of urban transport systems. Thus proper strategies and actions need to be prioritized to leverage the sustainability-related co-benefits of active transport
Preparation of metallic target of 100Mo for production of 99mTc in cyclotron
Introduction
Technetium-99m, the daughter of 99Mo is the most commonly used radioisotope in nuclear medicine [1–2]. Current global crisis of 99Mo supply, aging of nuclear reactors and staggering costs force the search for alternative sources of 99mTc. Radioisotope Centre POLATOM joined the IAEA Coordinated Research Project on “Accelerator-based Alternatives to Non-HEU Production of 99Mo/99mTc”. The planned outcome of this project is development of 99mTc production method using the reaction of 100Mo(p,2n)99mTc [3] in Polish cyclotron.
This work presents the results concerning preparation of 100Mo target for irradiation with protons.
Material and Methods
The manufacturing of Mo target was performed using pressing of molybdenum powder into pellets and its sintering in hydrogen atmosphere at 1600 oC [4]. For this purpose a tantalum and stainless steel plates were used as support. Several pellets using molybdenum powder with particles size of 2 µm in diameter were pressed at different values of pressure.
Results and Conclusion
The optimized parameters of pressing molyb-denum pellets with various sizes are given in TABLE 1. It was found that the pellets did not adhere neither to the tantalum nor stainless steel plates but they conducted electricity very well. Pellets prepared with higher pressure were more mechanically resistant, however application, even the highest used pressure did not ensure its satisfactory stability.
In order to improve mechanical strength, pressed Mo pellets were sintered in hydrogen atmosphere at temperature of 1600 °C. As a result of this process dimensions of Mo pellets decreased: diameter by 13 %, thickness by 12 %, weight by 1.5 %, volume by 34 % while density increased by 50 %. The changes of these parameters are associated with reduction of molybdenum oxide and removal of oxygen from intermetallic space. It was confirmed by photos of microscopic cross section of pellets before and after sintering. It was observed, that after sintering Mo pellets got a metallic form with very high hardness and mechanical strength
Evidence of environmental strains on charge injection in silole based organic light emitting diodes
Using d. functional theory (DFT) computations, the authors demonstrated a
substantial skeletal relaxation when the structure of
2,5-bis-[4-anthracene-9-yl-phenyl]-1,1-dimethyl-3,4-diphenyl-silole (BAS) is
optimized in the gas-phase comparing with the mol. structure detd. from
monocrystal x-ray diffraction. The origin of such a relaxation is explained by
a strong environmental strains induced by the presence of anthracene entities.
Also, the estn. of the frontier orbital levels showed that this structural
relaxation affects mainly the LUMO that is lowered of 190 meV in the gas phase.
To check if these theor. findings would be confirmed for thin films of BAS, the
authors turned to UV photoemission spectroscopy and/or inverse photoemission
spectroscopy and electrooptical measurements. The study of the c.d. or voltage
and luminance or voltage characteristics of an ITO/PEDOT/BAS/Au device clearly
demonstrated a very unusual temp.-dependent behavior. Using a thermally
assisted tunnel transfer model, this behavior likely originated from the
variation of the electronic affinity of the silole deriv. with the temp. The
thermal agitation relaxes the mol. strains in thin films as it is shown when
passing from the cryst. to the gas phase. The relaxation of the intramol. thus
induces an increase of the electronic affinity and, as a consequence, the more
efficient electron injection in org. light-emitting diodes
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EFFECT OF LOW DOSES OF LOW-LET RADIATION ON THE INNATE ANTITUMOR REACTIONS IN RADIORESISTANT AND RADIOSENSITIVE MICE
BALB/c and C57BL/6 mice differ in their Th1/Th2 lymphocyte and M1/M2 macrophage phenotypes, radiosensitivity, and post-irradiation tumor incidence. In this study we evaluated the effects of repeated low-level exposures to X-rays on the development of artificial tumor colonies in the lungs of animals from the two strains and cytotoxic activities of natural killer (NK) cells and macrophages obtained from these mice. After ten daily irradiations of BALB/c or C57BL/6 mice with 0.01, 0.02, and 0.1 Gy X-rays NK cell-enriched splenocytes collected from the animals demonstrated significant and comparable up-regulation of their anti-tumor cytotoxic function. Likewise, peritoneal macrophages collected from the two irradiated strains of mice exhibited the similarly stimulated cytotoxicities against susceptible tumor cells and produced significantly more nitric oxide. These results were accompanied by the significantly reduced numbers of the neoplastic colonies induced in the lungs by intravenous injection of syngeneic tumor cells. The obtained results indicate that ten low-level irradiations with X-rays stimulate the generally similar anti-tumor reactions in BALB/c and C57BL/6 mice
Thermodynamic study of benzocaine insertion into different lipid bilayers
Despite the general consensus concerning the role played by sodium channels in the molecular mechanism of local anesthetics, the potency of anaesthetic drugs also seems to be related with their solubility in lipid bilayers. In this respect, this work represents a thermodynamic study of benzocaine insertion into lipid bilayers of different compositions by means of molecular dynamics simulation. Thus, the free energy profiles associated with benzocaine insertion into symmetric lipid bilayers composed of different proportions of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylserine were studied. From the simulation results, a maximum in the free energy (ΔG) profile was measured in the region of the lipid/solution interface. This free energy barrier appears to be very much dependent on the lipid composition of the membrane. On the other hand, the minimum free energy (ΔG) within the bilayer remained almost independent of the lipid composition of the bilayer. By repeating the study at different temperatures, it was seen how the spontaneity of benzocaine insertion into the lipid bilayer is due to an increase in the entropy associated with the process.Fil: LĂłpez Cascales, JosĂ© Javier. Universidad Politecnica de Cartagena; EspañaFil: Oliveira Costa, Sara D.. Universidad Politecnica de Cartagena; EspañaFil: Porasso, Rodolfo Daniel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico San Luis. Instituto de Matemática Aplicada de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias FĂsico Matemáticas y Naturales. Departamento de FĂsica; Argentin
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