44 research outputs found
Self-assembly of Microcapsules via Colloidal Bond Hybridization and Anisotropy
Particles with directional interactions are promising building blocks for new
functional materials and may serve as models for biological structures.
Mutually attractive nanoparticles that are deformable due to flexible surface
groups, for example, may spontaneously order themselves into strings, sheets
and large vesicles. Furthermore, anisotropic colloids with attractive patches
can self-assemble into open lattices and colloidal equivalents of molecules and
micelles. However, model systems that combine mutual attraction, anisotropy,
and deformability have---to the best of our knowledge---not been realized.
Here, we synthesize colloidal particles that combine these three
characteristics and obtain self-assembled microcapsules. We propose that mutual
attraction and deformability induce directional interactions via colloidal bond
hybridization. Our particles contain both mutually attractive and repulsive
surface groups that are flexible. Analogous to the simplest chemical bond,
where two isotropic orbitals hybridize into the molecular orbital of H2, these
flexible groups redistribute upon binding. Via colloidal bond hybridization,
isotropic spheres self-assemble into planar monolayers, while anisotropic
snowman-like particles self-assemble into hollow monolayer microcapsules. A
modest change of the building blocks thus results in a significant leap in the
complexity of the self-assembled structures. In other words, these relatively
simple building blocks self-assemble into dramatically more complex structures
than similar particles that are isotropic or non-deformable
Mastitis diagnostics and performance monitoring: a practical approach
In this paper a review is given of frequently used mastitis diagnostic methods in modern dairy practice. Methods used at the quarter, cow, herd and regional or national level are discussed, including their usability for performance monitoring in udder health. Future developments, such as systems in which milk-derived parameters are combined with modern analytical techniques, are discussed. It is concluded that, although much knowledge is available and science is still developing and much knowledge is available, it is not always fully exploited in practice
Quantitative imaging of concentrated suspensions under flow
We review recent advances in imaging the flow of concentrated suspensions,
focussing on the use of confocal microscopy to obtain time-resolved information
on the single-particle level in these systems. After motivating the need for
quantitative (confocal) imaging in suspension rheology, we briefly describe the
particles, sample environments, microscopy tools and analysis algorithms needed
to perform this kind of experiments. The second part of the review focusses on
microscopic aspects of the flow of concentrated model hard-sphere-like
suspensions, and the relation to non-linear rheological phenomena such as
yielding, shear localization, wall slip and shear-induced ordering. Both
Brownian and non-Brownian systems will be described. We show how quantitative
imaging can improve our understanding of the connection between microscopic
dynamics and bulk flow.Comment: Review on imaging hard-sphere suspensions, incl summary of
methodology. Submitted for special volume 'High Solid Dispersions' ed. M.
Cloitre, Vol. xx of 'Advances and Polymer Science' (Springer, Berlin, 2009);
22 pages, 16 fig
The effects of dissection-room experiences and related coping strategies among Hungarian medical students
Background:
Students get their first experiences of dissecting human cadavers in the practical classes of anatomy
and pathology courses, core components of medical education. These experiences form an important part of the
process of becoming a doctor, but bring with them a special set of problems.
Methods:
Quantitative, national survey (n = 733) among medical students, measured reactions to dissection
experiences and used a new measuring instrument to determine the possible factors of coping.
Results:
Fifty per cent of students stated that the dissection experience
does not affect them
. Negative effects were
significantly more frequently reported by women and students in clinical training (years 3,4,5,6). The predominant
factor in the various coping strategies for dissection practicals is
cognitive coping
(rationalisation, intellectualisation).
Physical
and
emotional
coping strategies followed, with similar mean scores. Marked gender differences also
showed up in the application of coping strategies: there was a clear dominance of emotional-based coping among
women. Among female students, there was a characteristic decrease in the physical repulsion factor in reactions to
dissection in the later stages of study.
Conclusions:
The experience of dissection had an emotional impact on about half of the students. In general,
students considered these experiences to be an important part of becoming a doctor. Our study found that
students chiefly employed cognitive coping strategies to deal with their experiences.
Dissection-room sessions are important for learning emotional as well as technical skills. Successful coping is
achieved not by repressing emotions but by accepting and understanding the negative emotions caused by the
experience and developing effective strategies to deal with them.
Medical training could make better use of the learning potential of these experiences
Population biology of Allocreadium lobatum Wallin, 1909 (Digenea: Allocreadiidae) in the creek chub, Semotilus atromaculatus, mitchill (Osteichthyes: Cyprinadae), in a Nebraska Creek, USA
Determining the validity of hospital laboratory reference intervals for healthy young adults participating in early clinical trials of candidate vaccines.
This was a retrospective study to determine the validity of institutional reference intervals for interpreting biochemistry and hematology results in healthy adults in the context of clinical trials of preventive vaccines. An example population of 974 healthy adults participating in clinical trials at the Jenner Institute, Oxford, UK, between 1999 and 2009 was studied. Methods for calculating the central 95% ranges and determining the coefficients of within person variation were demonstrated. Recommendations have been made as to how these data can be usefully applied to the interpretation of blood results in healthy adult subjects for the purposes of clinical trial inclusion decisions and post-vaccination safety monitoring
Incidental Diagnosis in Healthy Clinical Trial Subjects
Previously unrecognized medical conditions identified in volunteers for early phase clinical studies have significant clinical and ethical implications for the participant. It is therefore crucial that the potential for unexpected diagnosis is addressed during the informed consent process. But the frequency of incidental diagnosis in healthy volunteers who attend for clinical trial screening remains unclear. To assess this we retrospectively analyzed 1,131 independent screening visits for 990 volunteers at a single academic center over a 10-year period to describe the frequency and nature of new clinical findings. Overall 23 of 990 volunteers (2.3%) were excluded at screening for a newly diagnosed medical abnormality. Some clinically important conditions, such as nephrotic syndrome and familial hypercholesterolemia were identified. The frequency of abnormalities was associated with increasing age in males (p= 0.02 χ2 for trend) but not females (p= 0.82). These data will assist those planning and conducting phase I/II vaccine trials in healthy volunteers, and importantly should strengthen the informed consent of future trial participants. Clin Trans Sci 2012; Volume 5: 348-350 © 2012 Wiley Periodicals, Inc