Boojums and the Shapes of Domains in Monolayer Films

Domains in Langmuir monolayers support a texture that is the two-dimensional version of the feature known as a boojum. Such a texture has a quantifiable effect on the shape of the domain with which it is associated. The most noticeable consequence is a cusp-like feature on the domain boundary. We report the results of an experimental and theoretical investigation of the shape of a domain in a Langmuir monolayer. A further aspect of the investigation is the study of the shape of a ``bubble'' of gas-like phase in such a monolayer. This structure supports a texture having the form of an inverse boojum. The distortion of a bubble resulting from this texture is also studied. The correspondence between theory and experiment, while not perfect, indicates that a qualitative understanding of the relationship between textures and domain shapes has been achieved.Comment: replaced with published version, 10 pages, 13 figures include

Towards a Tetravalent Chemistry of Colloids

We propose coating spherical particles or droplets with anisotropic nano-sized objects to allow micron-scale colloids to link or functionalize with a four-fold valence, similar to the sp3 hybridized chemical bonds associated with, e.g., carbon, silicon and germanium. Candidates for such coatings include triblock copolymers, gemini lipids, metallic or semiconducting nanorods and conventional liquid crystal compounds. We estimate the size of the relevant nematic Frank constants, discuss how to obtain other valences and analyze the thermal distortions of ground state configurations of defects on the sphere.Comment: Replaced to improve figures. 4 figures Nano Letter

The Critical Behaviour of Potts models with symmetry breaking fields

The $Q$-state Potts model in two dimensions in the presence of external magnetic fields is studied. For general $Q\geq3$ special choices of these magnetic fields produce effective models with smaller $Z(Q')$ symmetry $(Q'< Q)$. The phase diagram of these models and their critical behaviour are explored by conventional finite-size scaling and conformal invariance. The possibility of multicritical behavior, for finite values of the symmetry breaking fields, in the cases where $Q>4$ is also analysed. Our results indicate that for effective models with $Z(Q')$ symmetry $(Q'\leq4)$ the multicritical point occurs at zero field. This last result is also corroborated by Monte Carlo simulations.Comment: 15 pages (standart LaTex), 2 figure (PostScript) available by request to [email protected]

Hexatic Order and Surface Ripples in Spherical Geometries

In flat geometries, two dimensional hexatic order has only a minor effect on capillary waves on a liquid substrate and on undulation modes in lipid bilayers. However, extended bond orientational order alters the long wavelength spectrum of these ripples in spherical geometries. We calculate this frequency shift and suggest that it might be detectable in lipid bilayer vesicles, at the surface of liquid metals and in multielectron bubbles in liquid helium at low temperatures. Hexatic order also leads to a shift in the threshold for the fission instability induced in the later two systems by an excess of electric charge.Comment: 5 pages, 1 figure; revised version; to appear in Phys. Rev. Let

Novel Phases and Reentrant Melting of Two Dimensional Colloidal Crystals

We investigate two-dimensional (2d) melting in the presence of a one-dimensional (1d) periodic potential as, for example, realized in recent experiments on 2d colloids subjected to two interfering laser beams. The topology of the phase diagram is found to depend primarily on two factors: the relative orientation of the 2d crystal and the periodic potential troughs, which select a set of Bragg planes running parallel to the troughs, and the commensurability ratio p= a'/d of the spacing a' between these Bragg planes to the period d of the periodic potential. The complexity of the phase diagram increases with the magnitude of the commensurabilty ratio p. Rich phase diagram, with ``modulated liquid'', ``floating'' and ``locked floating'' solid and smectic phases are found. Phase transitions between these phases fall into two broad universality classes, roughening and melting, driven by the proliferation of discommensuration walls and dislocations, respectively. We discuss correlation functions and the static structure factor in these phases and make detailed predictions of the universal features close to the phase boundaries. We predict that for charged systems with highly screened short-range interactions these melting transitions are generically reentrant as a function of the strength of the periodic potential, prediction that is in accord with recent 2d colloid experiments. Implications of our results for future experiments are also discussed.Comment: 37 pages, 24 figure

Static Scaling Behavior of High-Molecular-Weight Polymers in Dilute Solution: A Reexamination

Previous theories of dilute polymer solutions have failed to distinguish clearly between two very different ways of taking the long-chain limit: (I) $N \to\infty$ at fixed temperature $T$, and (II) $N \to\infty$, $T \to T_\theta$ with $x \equiv N^\phi (T-T_\theta)$ fixed. I argue that the modern two-parameter theory (continuum Edwards model) applies to case II --- not case I --- and in fact gives exactly the crossover scaling functions for $x \ge 0$ modulo two nonuniversal scale factors. A Wilson-type renormalization group clarifies the connection between crossover scaling functions and continuum field theories. [Also contains a general discussion of the connection between the Wilson and field-theoretic renormalization groups. Comments solicited.]Comment: 10 pages including 1 figure, 181159 bytes Postscript (NYU-TH-93/05/01

EORTC consensus recommendations for the treatment of mycosis fungoides/Sézary syndrome - Update 2023.

On behalf of the EORTC Cutaneous Lymphoma Tumours Group (EORTC-CLTG) and following up on earlier versions published in 2006 and 2017 this document provides an updated standard for the treatment of mycosis fungoides and Sézary syndrome (MF/SS). It considers recent relevant publications and treatment options introduced into clinical practice after 2017. Consensus was established among the authors through a series of consecutive consultations in writing and a round of discussion. Treatment options are assigned to each disease stage and, whenever possible and clinically useful, separated into first- and second line options annotated with levels of evidence. Major changes to the previous version include the incorporation of chlormethine, brentuximab vedotin, and mogamulizumab, recommendations on the use of pegylated interferon α (after withdrawal of recombinant unpegylated interferons), and the addition of paragraphs on supportive therapy and on the care of older patients. Still, skin-directed therapies are the most appropriate option for early-stage MF and most patients have a normal life expectancy but may suffer morbidity and impaired quality of life. In advanced disease treatment options have expanded recently. Most patients receive multiple consecutive therapies with treatments often having a relatively short duration of response. For those patients prognosis is still poor and only for a highly selected subset long term remission can be achieved with allogeneic stem cell transplantation. Understanding of the disease, its epidemiology and clinical course, and its most appropriate management are gradually advancing, and there is well-founded hope that this will lead to further improvements in the care of patients with MF/SS

Guidelines on the use of extracorporeal photopheresis

Peer reviewe

Herringbone ordering and lattice distortions in a planar-molecule model for Langmuir monolayers

A model of planar molecules, made up of "atoms" interacting by Lennard-Jones potentials and arranged to mimic the cross section of alkyl chains, is used to study the problem of backbone plane ordering in Langmuir monolayers. It is shown that two minima of the interaction energy are reached if molecules lie on the sites of a centered rectangular lattice in a herringbone configuration with two different dihedral angles. These orientationally ordered phases can be related to the so-called herringbone and pseudoherringbone structures, whose lattice distortions qualitatively agree with those determined by means of grazing incidence x-ray diffraction experiments on Langmuir monolayers. A third energy minimum is obtained for a configuration of parallel molecules on an oblique lattice, which has also been observed in some experiments. The competition between the three phases is investigated, upon varying geometric parameters of the model molecules and surface pressure. The effect of temperature is analyzed in a mean field approximation, by taking into account the orientational entropy contribution on a lattice system with variable unit cell parameters. In this framework the transition to an orientationally disordered phase is also pointed out

Characteristics associated with significantly worse quality of life in mycosis fungoides/Sezary syndrome from the Prospective Cutaneous Lymphoma International Prognostic Index (PROCLIPI) study

Background Mycosis fungoides (MF) and Sezary Syndrome (SS) are the most common cutaneous T-cell lymphomas. MF/SS is accompanied by considerable morbidity from pain, itching and disfigurement. Aim To identify factors associated with poorer health-related quality of life (HRQoL) in patients newly diagnosed with MF/SS. Methods Patients enrolled into Prospective Cutaneous Lymphoma International Prognostic Index (PROCLIPI; an international observational study in MF/SS) had their HRQoL assessed using the Skindex-29 questionnaire. Skindex-29 scores were analysed in relation to patient- and disease-specific characteristics. Results The study population consisted of 237 patients [60 center dot 3% male; median age 60 years, (interquartile range 49-70)], of whom 179 had early MF and 58 had advanced MF/SS. In univariate analysis, HRQoL, as measured by Skindex-29, was worse in women, SS, late-stage MF, those with elevated lactate dehydrogenase, alopecia, high modified Severity Weighted Assessment Tool and confluent erythema. Linear regression models only identified female gender (beta = 8 center dot 61; P = 0 center dot 003) and alopecia (beta = 9 center dot 71, P = 0 center dot 02) as independent predictors of worse global HRQoL. Item-level analysis showed that the severe impairment in symptoms [odds ratio (OR) 2 center dot 14, 95% confidence interval (CI) 1 center dot 19-3 center dot 89] and emotions (OR 1 center dot 88, 95% CI 1 center dot 09-3 center dot 27) subscale scores seen in women was caused by more burning/stinging, pruritus, irritation and greater feelings of depression, shame, embarrassment and annoyance with their diagnosis of MF/SS. Conclusions HRQoL is significantly more impaired in newly diagnosed women with MF/SS and in those with alopecia. As Skindex-29 does not include existential questions on cancer, which may cause additional worry and distress, a comprehensive validated cutaneous T-cell lymphoma-specific questionnaire is urgently needed to more accurately assess disease-specific HRQoL in these patients.Peer reviewe