Conformal lattice of magnetic bubble domains in garnet film

We report experimental observations of magnetic bubble domain arrays with no apparent translational symmetry. Additionally the results of comparative numerical studies are discussed. Our goal is to present experimental evidence for natural occurence of conformal structures.Comment: 7 pages, 2 figures, LaTeX2e, accepted as paper E090 at JEMS'01 (Joint European Magnetic Symposia, formerly EMMA + MRM), August 28th to September 1st, 2001, Grenoble, Franc

Subspecies typing of Streptococcus agalactiae based on ribosomal subunit protein mass variation by MALDI-TOF MS

Background: A ribosomal subunit protein (rsp)-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) method was developed for fast subspecies-level typing of Streptococcus agalactiae (Group B Streptococcus, GBS), a major cause of neonatal sepsis and meningitis. Methods: A total of 796 GBS whole genome sequences, covering the genetic diversity of the global GBS population, were used to in silico predict molecular mass variability of 28 rsp and to identify unique rsp mass combinations, termed “rsp-profiles”. The in silico established GBS typing scheme was validated by MALDI-TOF MS analysis of GBS isolates at two independent research sites in Europe and South East Asia. Results: We identified in silico 62 rsp-profiles, with the majority (>80%) of the 796 GBS isolates displaying one of the six rsp-profiles 1-6. These dominant rsp-profiles classify GBS strains in high concordance with the core-genome based phylogenetic clustering. Validation of our approach by in-house MALDI-TOF MS analysis of 248 GBS isolates and external analysis of 8 GBS isolates showed that across different laboratories and MALDI-TOF MS platforms, the 28 rsp were detected reliably in the mass spectra, allowing assignment of clinical isolates to rsp-profiles at high sensitivity (99%) and specificity (97%). Our approach distinguishes the major phylogenetic GBS genotypes, identifies hyper-virulent strains, predicts the probable capsular serotype and surface protein variants and distinguishes between GBS genotypes of human and animal origin. Conclusion: We combine the information depth of whole genome sequences with the highly cost efficient, rapid and robust MALDI-TOF MS approach facilitating high-throughput, inter-laboratory, large-scale GBS epidemiological and clinical studies based on pre-defined rsp-profiles

SY30-3THE USE OF SOPHISMS IN SUSTAINING DISULFIRAM

Disulfiram's use is not supported by scientific evidence but nevertheless largely advocated and used. This would be less odd in case of lacking or just preliminary evidence. What is peculiar in the case of disulfiram's prescription is its persistence against evidence. Hence arise the question how it is possible that its use can be supported, i.e. by what type of arguments. The goal of an argument is to persuade, the goal of logic and argumentation is additionally to persuade for good reasons. In this sense, a good argument would give good reasons to believe the conclusion. Fallacies are bad arguments, either because they have weak logic, or because they rely on a false premise. Sophisms are intentionally used fallacies, an attempt to persuade opponents that a specific conclusion is true, by means other than by proposing relevant evidence. Proponents of fallacious arguments may use them either because they are incapable or because they are unwilling to accept their arguments to be fallacious. We therefore formulate the hypothesis that the frequency use of fallacious arguments within our otherwise supposedly evidence based discipline may be indicative of (a) a scientifically immature discipline, and/or (b) a moralistically intermingled disciplin

The ‘Golden Age’ of synesthesia inquiry in the late Nineteenth Century (1876–1895)

Synesthesia is a rare neurological trait that causes unusual, often cross-sensory, experiences (e.g., seeing colors when listening to music). This article traces the history of synesthesia in the period 1876 to 1895. In this period, there was considerable debate over the nature of synesthesia, its causes, and how it should be named. The issue also attracted the leading thinkers of the time and, within a few years, the number of reported cases of synesthesia jumped from around ten to more than 100. For this reason, this period can be regarded as the “golden age” for synesthesia research in the nineteenth century. In this time, scientists debated whether synesthesia was a form of pathology or an alternative manifestation of intelligence. The differing roles of heredity and environment were contested, and there were several explanations proposed as to its neural basis. These enquiries went to the heart of the debate as to whether synesthetic experiences are special in any way or, instead, a more vivid manifestation of a more general capacity for forming associations

Magnetoliposomes: opportunities and challenges

Combining liposomes with magnetic nanoparticles is an intriguing approach to create multifunctional vesicles for medical applications, which range from controlled drug delivery vehicles to diagnostic imaging enhancers. Over the past decade, significant effort has been invested in developing such hybrids - widely known as magnetoliposomes - and has led to numerous new concepts. This review provides an overview on of the current state of the art in this field. The concept of magnetic fluid hyperthermia and stimuli-responsive nanoparticles for drug delivery is briefly recapitulated. The materials needed for these hybrids are addressed as well. The three typically followed approaches to associate magnetic nanoparticles to the liposomes are described and discussed more in detail. The final chapters are dedicated to the analytical methods used to characterize these hybrids and to theoretical considerations relevant for bilayer-embedded nanoparticle

Ellipsometric measurements by use of photon pairs generated by spontaneous parametric down-conversion

We present a novel interferometric technique for performing ellipsometric measurements. This technique relies on the use of a non-classical optical source, namely, polarization-entangled twin photons generated by spontaneous parametric down-conversion from a nonlinear crystal, in conjunction with a coincidence-detection scheme. Ellipsometric measurements acquired with this scheme are absolute; i.e., they do not require source and detector calibration.Comment: 10 pages, accepted for publication in Optics Letter

Cellular uptake and cell-to-cell transfer of polyelectrolyte microcapsules within a triple co-culture system representing parts of the respiratory tract

Polyelectrolyte multilayer microcapsules around 3.4 micrometers in diameter were added to epithelial cells, monocyte-derived macrophages, and dendritic cells in vitro and their uptake kinetics were quantified. All three cell types were combined in a triple co-culture model, mimicking the human epithelial alveolar barrier. Hereby, macrophages were separated in a three-dimensional model from dendritic cells by a monolayer of epithelial cells. While passing of small nanoparticles has been demonstrated from macrophages to dendritic cells across the epithelial barrier in previous studies, for the micrometer-sized capsules, this process could not be observed in a significant amount. Thus, this barrier is a limiting factor for cell-to-cell transfer of micrometer-sized particles

Collective and single cell behavior in epithelial contact inhibition

Control of cell proliferation is a fundamental aspect of tissue physiology central to morphogenesis, wound healing and cancer. Although many of the molecular genetic factors are now known, the system level regulation of growth is still poorly understood. A simple form of inhibition of cell proliferation is encountered in vitro in normally differentiating epithelial cell cultures and is known as "contact inhibition". The study presented here provides a quantitative characterization of contact inhibition dynamics on tissue-wide and single cell levels. Using long-term tracking of cultured MDCK cells we demonstrate that inhibition of cell division in a confluent monolayer follows inhibition of cell motility and sets in when mechanical constraint on local expansion causes divisions to reduce cell area. We quantify cell motility and cell cycle statistics in the low density confluent regime and their change across the transition to epithelial morphology which occurs with increasing cell density. We then study the dynamics of cell area distribution arising through reductive division, determine the average mitotic rate as a function of cell size and demonstrate that complete arrest of mitosis occurs when cell area falls below a critical value. We also present a simple computational model of growth mechanics which captures all aspects of the observed behavior. Our measurements and analysis show that contact inhibition is a consequence of mechanical interaction and constraint rather than interfacial contact alone, and define quantitative phenotypes that can guide future studies of molecular mechanisms underlying contact inhibition

Characterizing nanoparticles in complex biological media and physiological fluids with depolarized dynamic light scattering

Light scattering is one of the few techniques available to adequately characterize suspended nanoparticles (NPs) in real time and in situ. However, when it comes to NPs in multicomponent and optically complex aqueous matrices – such as biological media and physiological fluids – light scattering suffers from lack of selectivity, as distinguishing the relevant optical signals from the irrelevant ones is very challenging. We meet this challenge by building on depolarized scattering: Unwanted signals from the matrix are completely suppressed. This approach yields information with an unprecedented signal-to-noise ratio in favour of the NPs and NP-biomolecule corona complexes, which in turn opens the frontier to scattering-based studies addressing the behaviour of NPs in complex physiological/biological fluids

Taylor dispersion of nanoparticles

The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced “industrial” particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori