Overtwisted energy-minimizing curl eigenfields

We consider energy-minimizing divergence-free eigenfields of the curl operator in dimension three from the perspective of contact topology. We give a negative answer to a question of Etnyre and the first author by constructing curl eigenfields which minimize $L^2$ energy on their co-adjoint orbit, yet are orthogonal to an overtwisted contact structure. We conjecture that $K$-contact structures on $S^1$-bundles always define tight minimizers, and prove a partial result in this direction.Comment: published versio

Sum-over-states vs quasiparticle pictures of coherent correlation spectroscopy of excitons in semiconductors; femtosecond analogues of multidimensional NMR

Two-dimensional correlation spectroscopy (2DCS) based on the nonlinear optical response of excitons to sequences of ultrafast pulses, has the potential to provide some unique insights into carrier dynamics in semiconductors. The most prominent feature of 2DCS, cross peaks, can best be understood using a sum-over-states picture involving the many-body eigenstates. However, the optical response of semiconductors is usually calculated by solving truncated equations of motion for dynamical variables, which result in a quasiparticle picture. In this work we derive Green's function expressions for the four wave mixing signals generated in various phase-matching directions and use them to establish the connection between the two pictures. The formal connection with Frenkel excitons (hard-core bosons) and vibrational excitons (soft-core bosons) is pointed out.Comment: Accepted to Phys. Rev.

Indignation for moral violations suppresses the tongue motor cortex: Preliminary TMS evidence

We commonly label moral violations in terms of 'disgust', yet it remains unclear whether metaphorical expressions linking disgust and morality are genuinely shared at the cognitive/neural level. Using transcranial magnetic stimulation (TMS), we provide new insights into this debate by measuring motor-evoked potentials (MEPs) from the tongue generated by TMS over the tongue primary motor area (tM1) in a small group of healthy participants presented with vignettes of moral transgressions and non-moral vignettes. We tested whether moral indignation, felt while evaluating moral vignettes, affected tM1 excitability. Vignettes exerted a variable influence on MEPs with no net effect of the moral category. However, in accordance with our recent study documenting reduced tM1 excitability during exposure to pictures of disgusting foods or facial expressions of distaste, we found that the vignettes of highly disapproved moral violations reduced tM1 excitability. Moreover, tM1 excitability and moral indignation were linearly correlated: the higher the moral indignation, the lower the tM1 excitability. Respective changes in MEPs were not observed in a non-oral control muscle, suggesting a selective decrease of tM1 excitability. These preliminary findings provide neurophysiological evidence supporting the hypothesis that morality might have originated from the more primitive experience of oral distaste

Tight Beltrami fields with symmetry

Let $M$ be a compact orientable Seifered fibered 3-manifold without a boundary, and $\alpha$ an $S^1$-invariant contact form on $M$. In a suitable adapted Riemannian metric to $\alpha$, we provide a bound for the volume $\text{Vol}(M)$ and the curvature, which implies the universal tightness of the contact structure $\xi=\ker\alpha$.Comment: 26 page

Off-axis electron holography of bacterial cells and magnetic nanoparticles in liquid

The mapping of electrostatic potentials and magnetic fields in liquids usingelectron holography has been considered to be unrealistic. Here, we showthat hydrated cells ofMagnetospirillum magneticumstrain AMB-1 and assem-blies of magnetic nanoparticles can be studied using off-axis electronholography in a fluid cell specimen holder within the transmission electronmicroscope. Considering that the holographic object and reference waveboth pass through liquid, the recorded electron holograms show sufficientinterference fringe contrast to permit reconstruction of the phase shift ofthe electron wave and mapping of the magnetic induction from bacterialmagnetite nanocrystals. We assess the challenges of performingin situmagne-tization reversal experiments using a fluid cell specimen holder, discussapproaches for improving spatial resolution and specimen stability, and outlinefuture perspectives for studying scientific phenomena, ranging from interpar-ticle interactions in liquids and electrical double layers at solid–liquidinterfaces to biomineralization and the mapping of electrostatic potentialsassociated with protein aggregation and folding

The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX): Description and Early Pilot Survey Results

The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) will outfit the 10 m HET with a new wide field and an array of 150 integral-field spectrographs to survey a 420 sq. deg. area in the north Galactic cap. Each fiber-coupled unit spectrograph will cover 350-550 nm, simultaneously. This instrument, called VIRUS, will produce ~34,000 spectra per exposure, and will open up the emission-line universe to large surveys for the first time. The survey will detect 0.8 million Lyman-alpha emitting (LAE) galaxies with 1.9<z<3.5 and more than a million [OII] emitting galaxies with z<0.5. The 3-D map of LAE galaxies in 9 cubic Gpc volume will be used to measure the expansion history at this early epoch using baryonic acoustic oscillations and the shape of the power spectrum. The aim of HETDEX is to provide a direct detection of dark energy at z~3. The measurement will constrain the evolution of dark energy and will also provide 0.1%-level accuracy on the curvature of the Universe, ten times better than current. The prototype of the VIRUS unit spectrograph (VIRUS-P) is a powerful instrument in its own right. Used on the McDonald 2.7 m, it covers the largest area of any integral field spectrograph, and reaches wavelengths down to 340 nm. VIRUS-P is being used for a pilot survey to better measure the properties of LAE galaxies in support of HETDEX. We report initial results from this survey.Comment: 4 pages, 1 Postscript figure. Paper presented at conference "Panoramic Views of the Universe", Hayama, Japan, December 2007 (ASP Conference Series, in press

Lipid nanocarriers for hyperproliferative skin diseases

Hyperproliferative skin diseases (HSD) are a group of diseases that include cancers, pre-cancerous lesions and diseases of unknown etiology that present different skin manifestations in terms of the degree and distribution of the injuries. Anti-proliferative agents used to treat these diseases are so diverse, including 5-aminolevulinic acid, 5-fluorouracil, imiquimod, methotrexate, paclitaxel, podophyllotoxin, realgar, and corticosteroids in general. These drugs usually have low aqueous solubility, which consequently decreases skin permeation. Thus, their incorporation in lipid nanocarriers has been proposed with the main objective to increase the effectiveness of topical treatment and reduce side effects. This manuscript aims to describe the advantages of using lipid nanoparticles and liposomes that can be used to load diversity of chemically different drugs for the treatment of HSD.This research was funded by the Portuguese Science and Technology Foundation (FCT/MCT), European Funds (PRODER/COMPETE)—project UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020. The work is also supported by the National Science Centre within the MINIATURA 4 for a single research activity (grant no: 2020/04/X/ST5/00789) and by the START 2021 Program of the Foundation for Polish Science (FNP) granted to Aleksandra Zielínskainfo:eu-repo/semantics/publishedVersio

Lipid Nanocarriers for Hyperproliferative Skin Diseases

Hyperproliferative skin diseases (HSD) are a group of diseases that include cancers, pre-cancerous lesions and diseases of unknown etiology that present different skin manifestations in terms of the degree and distribution of the injuries. Anti-proliferative agents used to treat these diseases are so diverse, including 5-aminolevulinic acid, 5-fluorouracil, imiquimod, methotrexate, paclitaxel, podophyllotoxin, realgar, and corticosteroids in general. These drugs usually have low aqueous solubility, which consequently decreases skin permeation. Thus, their incorporation in lipid nanocarriers has been proposed with the main objective to increase the effectiveness of topical treatment and reduce side effects. This manuscript aims to describe the advantages of using lipid nanoparticles and liposomes that can be used to load diversity of chemically different drugs for the treatment of HSD. Keywords: lipid nanoparticles; liposomes; hyperproliferative skin diseases; antiproliferative drugs; skin cance

Useful immunohistochemical indicators in canine mast cell tumours

Morphological and immunohistochemical analysis of 45 canine mast cell tumours was performed to determine whether the proteins examined are useful for a more precise description of tumour morphology and a more reliable determination of the prognosis in patients. Tissue sections were stained according to the standard haematoxylin and eosin (HE) technique and with toluidine blue to demonstrate cytoplasmic granules. Immunohistochemical studies were performed, using the cell markers CD117 (c-kit), p16 and von Willebrand factor (FVIII). In CD117 three different staining patterns were observed: (1) membranous reaction, (2) intense staining of cytoplasm, and (3) a diffuse, delicate cytoplasmic reaction. Von Willebrand antibody was evaluated on the basis of the number of blood vessels stained. p16 expression was evaluated by scoring positive nuclear reaction. Positive expression was demonstrated for all examined antigens, but their level of expression differed depending on the grades of tumour malignancy. Statistical analysis of the results documented a pronounced positive correlation between the markers studied and the grade of tumour malignancy (P < 0.001). It was shown that each of the cell markers examined represents a useful prognostic indicator for patients with mast cell tumours. The calculated correlation coefficients demonstrate a strong association between the expressions of CD117, FVIII and p16, and the histological malignancy of a tumour

Shifting attention in viewer- and object-based reference frames after unilateral brain injury

The aims of the present study were to investigate the respective roles that object- and viewer-based reference frames play in reorienting visual attention, and to assess their influence after unilateral brain injury. To do so, we studied 16 right hemisphere injured (RHI) and 13 left hemisphere injured (LHI) patients. We used a cueing design that manipulates the location of cues and targets relative to a display comprised of two rectangles (i.e., objects). Unlike previous studies with patients, we presented all cues at midline rather than in the left or right visual fields. Thus, in the critical conditions in which targets were presented laterally, reorienting of attention was always from a midline cue. Performance was measured for lateralized target detection as a function of viewer-based (contra- and ipsilesional sides) and object-based (requiring reorienting within or between objects) reference frames. As expected, contralesional detection was slower than ipsilesional detection for the patients. More importantly, objects influenced target detection differently in the contralesional and ipsilesional fields. Contralesionally, reorienting to a target within the cued object took longer than reorienting to a target in the same location but in the uncued object. This finding is consistent with object-based neglect. Ipsilesionally, the means were in the opposite direction. Furthermore, no significant difference was found in object-based influences between the patient groups (RHI vs. LHI). These findings are discussed in the context of reference frames used in reorienting attention for target detection