Magnetic resonance spectral characterization of diffusion with chemical shift resolution

We present a modulated gradient spin-echo method (MGSE), which uses a train of sinusoidally shaped gradient pulses separated by 180-degree RF pulses. The RF pulses efficiently refocus chemical shifts and de-phasing due to susceptibility differences, resulting in undistorted, high-resolution diffusion weighted spectra. This allows for simultaneous spectral characterization of diffusion of several molecular components with different chemical shifts. Feasibility of the technique is demonstrated by following the diffusion of water, oil, and water-soluble salt in a highly concentrated water-in-oil emulsion

Upper secondary schools students\u27 knowledge and attitudes toward Eurasian Lynx

Znanje o živalih in stališča ljudi do živali pomembno vplivajo na ohranjanje in varovanje živalskih vrst. V raziskavi smo analizirali znanje in stališča dijakov o evrazijskem risu (Lynx lynx). Z anketnim vprašalnikom s preizkusom znanja smo anketirali dijake z območja Kočevja in Gorenjske. Zanimalo nas je znanje dijakov glede na spol, letnik izobraževanja in glede na to, ali se šolajo na območju, kjer je ris prisoten ali ne. Poleg znanja smo preverjali še stališča ter kako nanje vpliva znanje in območje šolanja. Ugotovili smo, da imajo dijaki malo znanja o evrazijskem risu, najmanj na področju ekologije. Na znanje vplivata spol, (dijaki imajo več znanja od dijakinj) in letnik izobraževanja (največ znanja imajo drugi letniki najmanj pa prvi). Med območji šolanja ni razlik v znanju. V analizi stališč dijakov smo ugotovili, da na stališča vpliva znanje. Dijaki z več znanja imajo bolj pozitivna stališča, kot dijaki s manj znanja. Poleg znanja na stališča vpliva območje šolanja. Dijaki, ki se izobražujejo na območju pojavljanja risa, imajo bolj pozitivna stališča do te živali, kot dijaki, ki živijo na območju, kjer risa ni. Za nadaljnje ohranjanje risa na območju Slovenije so pomembna pozitivna stališča vseh interesnih skupin do te živali. Pomembno je, da že v času gimnazijskega izobraževanja dijaki pridobijo čim več informacij o tej živali in razvijejo pozitivna stališča do nje.People\u27s knowledge and attitudes towards animals have a significant impact on the conservation and protection of these animals. In this study, we analyzed upper secondary school students\u27 knowledge and attitudes toward the Eurasian lynx (Lynx lynx). In order to test this, we created a questionnaire with a knowledge test and distributed it to students within two distinct regions of Slovenia (Kočevje and Gorenjska). We surveyed their degree of knowledge in regard to the Eurasian lynx based on the following factors: sex, year of education, and whether they were being educated in an area where the Eurasian lynx is present or not. We statistically assessed how their attitudes were influenced by degree of knowledge about the lynx and the region in which they were being educated. We found that students in both regions have little knowledge about the Eurasian lynx, and the least knowledge about the lynx as related to ecology. There was a difference in knowledge according to school year and according to sex, with males having more knowledge about the Eurasian lynx than females. There was no regional difference in knowledge between schools in Slovenia. In the analysis of the students\u27 attitudes, we found that knowledge influenced attitudes. Students with more knowledge about the lynx had more positive attitudes than students with less knowledge. In addition, region impacted students’ attitudes. Students who are educated in the area where the lynx is present have a more positive attitude towards this animal than the students who live in the area where the lynx is not present. When it comes to both conservation and protection of the Eurasian lynx in Slovenia, positive attitudes play a very important role. It is essential that upper secondary schools students are given as much knowledge as possible about the Eurasian lynx in order to develop positive attitudes towards it

Micelle Forms in Lyotropic Nematics and Cholesterics

Nematic and cholesteric lyotropic liquid crystals (lyomesophases based on micelles) with positive and negative diamagnetic aniiSotropy wexe studied by polaxizing microscopy. The textures of nematics oriented in a magnetic field confirm the disc- · like and rodlike structure of the lyomesophases. The textures of cholesterics show a characteristic helical structure where the pitch of the helix depends on the composition and temperature

Micelle Forms in Lyotropic Nematics and Cholesterics

Nematic and cholesteric lyotropic liquid crystals (lyomesophases based on micelles) with positive and negative diamagnetic aniiSotropy wexe studied by polaxizing microscopy. The textures of nematics oriented in a magnetic field confirm the disc- · like and rodlike structure of the lyomesophases. The textures of cholesterics show a characteristic helical structure where the pitch of the helix depends on the composition and temperature

Investigations of vesicle gels by pulsed and modulated gradient NMR diffusion techniques

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Vesicle gels are surfactant systems that form stiff gels with rather low amounts of surfactant. So far their structures have mostly been investigated using scattering techniques, which are generally appropriate for the study of structures on the nm-length-scale. Here we examine these gels using two complementary diffusion NMR techniques, which are both sensitive to structures on the μm-scale. The presented results imply structural features on the μm-scale, indicating a more complex structure than just that of densely packed small vesicles, as previously found for these systems. It is demonstrated that a combination of the diffusion NMR methods, described here, can provide useful insights, when morphological features extend over a wide range of length scales

Skupno etično odločanje zdravstvenih delavcev

Introduction: Making shared ethical decisions about patients' further healthcare involves coordinating the opinions of healthcare professionals, and patients and their relatives. The purpose of the research was to examine the joint ethical decision-making of healthcare professionals. Methods: A review of the scientific literature performed in the COBISS, Springer Link and PubMed databases was used. To search for literature in the Slovenian language, the following words were used: "etika", "zdravstveni delavci", "skupne odločitve" and in the English language: "ethics", "health professionals", "shared decision making". The literature review was carried out using the PRISMA diagram. Results were synthesized using thematic analysis. Results: 19 articles were included in the final analysis. We created three thematic categories: (1) ethical competence of healthcare workers, (2) problems in the area of joint ethical decision-making and (3) new approaches to joint ethical decision-making to improve outcomes in clinical practice. In the field of joint ethical decision-making of healthcare professionals, the importance of ethical competence, issues in the field of joint ethical decision-making and new approaches to joint ethical decision-making for improving results in clinical practice is demonstrated. Discussion and conclusion: The findings of the research contribute to illuminating the importance of joint ethical decision-making and giving an insight into the factors of joint ethical decision-making. The end result of certain ethical decisions that affect the interaction of healthcare professionals and all levels in healthcare are important

Dynamics of Air-Fluidized Granular System Measured by the Modulated Gradient Spin-echo

The power spectrum of displacement fluctuation of beads in the air-fluidized granular system is measured by a novel NMR technique of modulated gradient spin-echo. The results of measurement together with the related spectrum of the velocity fluctuation autocorrelation function fit well to an empiric formula based on to the model of bead caging between nearest neighbours; the cage breaks up after a few collisions \cite{Menon1}. The fit yields the characteristic collision time, the size of bead caging and the diffusion-like constant for different degrees of system fluidization. The resulting mean squared displacement increases proportionally to the second power of time in the short-time ballistic regime and increases linearly with time in the long-time diffusion regime as already confirmed by other experiments and simulations.Comment: 4 figures. Submited to Physical Review Letters, April 200

Coupling between Smectic and Twist Modes in Polymer Intercalated Smectics

We analyse the elastic energy of an intercalated smectic where orientationally ordered polymers with an average orientation varying from layer to layer are intercalated between smectic planes. The lowest order terms in the coupling between polymer director and smectic layer curvature are added to the smectic elastic energy. Integration over the smectic degrees of freedom leaves an effective polymer twist energy that has to be included into the total polymer elastic energy leading to a fluctuational renormalization of the intercalated polymer twist modulus. If the polymers are chiral this in its turn leads to a renormalization of the cholesteric pitch.Comment: 8 pages, 1 fig in ps available from [email protected] Replaced version also contains title and abstract in the main tex

Quantification of microscopic diffusion anisotropy disentangles effects of orientation dispersion from microstructure: Applications in healthy volunteers and in brain tumors

AbstractThe anisotropy of water diffusion in brain tissue is affected by both disease and development. This change can be detected using diffusion MRI and is often quantified by the fractional anisotropy (FA) derived from diffusion tensor imaging (DTI). Although FA is sensitive to anisotropic cell structures, such as axons, it is also sensitive to their orientation dispersion. This is a major limitation to the use of FA as a biomarker for “tissue integrity”, especially in regions of complex microarchitecture. In this work, we seek to circumvent this limitation by disentangling the effects of microscopic diffusion anisotropy from the orientation dispersion.The microscopic fractional anisotropy (μFA) and the order parameter (OP) were calculated from the contrast between signal prepared with directional and isotropic diffusion encoding, where the latter was achieved by magic angle spinning of the q-vector (qMAS). These parameters were quantified in healthy volunteers and in two patients; one patient with meningioma and one with glioblastoma. Finally, we used simulations to elucidate the relation between FA and μFA in various micro-architectures.Generally, μFA was high in the white matter and low in the gray matter. In the white matter, the largest differences between μFA and FA were found in crossing white matter and in interfaces between large white matter tracts, where μFA was high while FA was low. Both tumor types exhibited a low FA, in contrast to the μFA which was high in the meningioma and low in the glioblastoma, indicating that the meningioma contained disordered anisotropic structures, while the glioblastoma did not. This interpretation was confirmed by histological examination.We conclude that FA from DTI reflects both the amount of diffusion anisotropy and orientation dispersion. We suggest that the μFA and OP may complement FA by independently quantifying the microscopic anisotropy and the level of orientation coherence