Multidomain Skyrmion Lattice State in Cu2OSeO3.

Magnetic skyrmions in chiral magnets are nanoscale, topologically protected magnetization swirls that are promising candidates for spintronics memory carriers. Therefore, observing and manipulating the skyrmion state on the surface level of the materials are of great importance for future applications. Here, we report a controlled way of creating a multidomain skyrmion state near the surface of a Cu2OSeO3 single crystal, observed by soft resonant elastic X-ray scattering. This technique is an ideal tool to probe the magnetic order at the L3 edge of 3d metal compounds giving an average depth sensitivity of ∼50 nm. The single-domain 6-fold-symmetric skyrmion lattice can be broken up into domains, overcoming the propagation directions imposed by the cubic anisotropy by applying the magnetic field in directions deviating from the major cubic axes. Our findings open the door to a new way to manipulate and engineer the skyrmion state locally on the surface or on the level of individual skyrmions, which will enable applications in the future.

Néel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8.

Following the early prediction of the skyrmion lattice (SkL)--a periodic array of spin vortices--it has been observed recently in various magnetic crystals mostly with chiral structure. Although non-chiral but polar crystals with Cnv symmetry were identified as ideal SkL hosts in pioneering theoretical studies, this archetype of SkL has remained experimentally unexplored. Here, we report the discovery of a SkL in the polar magnetic semiconductor GaV4S8 with rhombohedral (C3v) symmetry and easy axis anisotropy. The SkL exists over an unusually broad temperature range compared with other bulk crystals and the orientation of the vortices is not controlled by the external magnetic field, but instead confined to the magnetic easy axis. Supporting theory attributes these unique features to a new Néel-type of SkL describable as a superposition of spin cycloids in contrast to the Bloch-type SkL in chiral magnets described in terms of spin helices.

In situ self-assembled organic interface layers for the controlled growth of oligothiophene thin films on ferroelectric Pb(Zr(0.2)Ti(0.8))O3.

We introduce an in situ vacuum procedure for the optimal preparation and analysis of self-assembled monolayers (SAMs) as used in organic molecular electronics on ferroelectric lead zirconate titanate (PZT) substrates. Excellent ordering of oligothiophene semiconductor layers is heavily promoted through the presence of an interfacial bi-functional SAM layer that binds to both the oxidic PZT surface and the organic semiconductor molecules. The described method can be extended to other material combinations, featuring a variety of substrate materials and molecular functionalities.

Unwinding of a skyrmion lattice by magnetic monopoles.

Skyrmion crystals are regular arrangements of magnetic whirls that exist in a wide range of chiral magnets. Because of their topology, they cannot be created or destroyed by smooth rearrangements of the direction of the local magnetization. Using magnetic force microscopy, we tracked the destruction of the skyrmion lattice on the surface of a bulk crystal of Fe(1-x)Co(x)Si (x = 0.5). Our study revealed that skyrmions vanish by a coalescence, forming elongated structures. Numerical simulations showed that changes of topology are controlled by singular magnetic point defects. They can be viewed as quantized magnetic monopoles and antimonopoles, which provide sources and sinks of one flux quantum of emergent magnetic flux, respectively.

Interface dipole formation of different ZnPcCl(8) phases on Ag(111) observed by Kelvin probe force microscopy.

Recently, we investigated the adsorption of octachloro zinc phthalocyanine (ZnPcCl(8)) on Ag(111) by scanning tunneling microscopy. Compared to the standard phthalocyanine, halogenated phthalocyanine molecules show a much more complex binding behavior, which results in the formation of three different structural phases. These phases follow from the ordering process with the formation of 8, 4 and 0 intermolecular hydrogen-halogen bonds (Abel et al 2006 ChemPhysChem 7 82). In the present work we investigate these phases by Kelvin probe force microscopy in order to quantitatively deduce the electric interface barrier of the first monolayer. Our measurements reveal that the binding behavior does not only affect the structural ordering but also the interface dipole formation, which leads to different work functions. The fact that we observe interface barriers of opposite signs between ordered and disordered molecular layers underlines the importance of exactly knowing the molecular arrangement at the interface when assembling organic molecule devices.

Adult polyglucosan body disease.

We describe a case of adult polyglucosan body disease with characteristic clinical symptoms of peripheral neuropathy, upper motor neuron signs, and bowel and bladder dysfunction. Sural nerve biopsy revealed diagnostic intra-axonal polyglucosan bodies. On electron microscopic examination, the inclusions were located mainly within myelinated nerve fibers and consisted of branched filaments that were 6 to 8 nm wide. The diagnosis of adult polyglucosan body disease was confirmed by a skin biopsy from the axilla showing similar inclusions in myoepithelial cells of apocrine glands. This report provides additional evidence that skin biopsy, to date advocated by a single case report only, may be a less invasive and simpler diagnostic alternative to sural nerve or brain biopsies.

[Case report of jellyfish injury]. / Fallstudie einer Quallenverletzung.

We are presenting a 47-year-old woman who was stung by jellyfish while bathing in the sea of Thailand. Immediately after the injury she developed sharp pain and urticarial erythema of the skin of the knees accompanied by muscle cramps of the entire body. After a few days a toxic contact dermatitis with edematous swelling and ulcerations developed, which did not respond to topical antibiotics or corticosteroids. Three weeks later the patient presented with a disseminated urticarial eruption, which at first responded well to topical treatment and systemic corticosteroids. Over the next few weeks, however, a relapse of the eruption and the ulcerations occurred. Raised titres of IgG and IgM antibodies against different jellyfish from the Indian and Pacific Ocean were detected in the patient's serum by the enzyme-linked immunosorbent assay. Antibodies against bees (class 1) and wasps (class 4) were found by the radioallergosorbent test. The clinical features and the immunological findings led to the diagnosis of toxic and allergic contact dermatitis to jellyfish venom. First aid and secondary treatment of jellyfish injuries are suggested.

[Low dosage cyclosporin A therapy in pyoderma gangrenosum. Experiences with 6 patients]. / Niedrig dosierte Cyclosporin-A-Therapie bei Pyoderma gangraenosum. Erfahrungen bei 6 Patienten.

Pyoderma gangraenosum can cause great therapeutic problems. High dosed corticosteroids are the treatment of choice. However, recalcitrant pyoderma gangraenosum or side effects from corticosteroid treatment may require therapeutic alternatives. Pyoderma gangraenosum responds excellently to treatment with cyclosporine A. Because of side effects and drug interactions, the patients must be selected and carefully and closely monitored. Six patients with pyoderma gangraenosum, unresponsive to various topical and systemic therapies, were treated with oral cyclosporine A at mean daily doses of approximately 3 mg/kg. Marked improvement of the skin lesions and complete healing occurred in all patients over a period of 3-6 months. Only one patient suffered a relapse after discontinuation of the treatment. No severe irreversible side effects occurred. The results show that low-dose cyclosporine A treatment can be considered a first-line treatment of pyoderma gangraenosum.

Cutaneous bacillary angiomatosis in a patient with chronic lymphocytic leukemia.

BACKGROUND: Bacillary angiomatosis is a recently described vascular disorder that is associated with infection by Bartonella henselae (formerly known as Rochalimaea henselae) and Bartonella quintana (formerly known as Rochalimaea quintana); this disorder usually occurs in patients with human immunodeficiency virus infection. We report a case of cutaneous bacillary angiomatosis that occurred in a patient with chronic lymphocytic leukemia. OBSERVATIONS: A 55-year-old man with chronic lymphocytic B-cell leukemia, Rai stage IV, presented with multiple angiomatous papules that clinically resembled pyogenic granulomas. Histopathologic examination revealed circumscribed lobules of small vessels with plump endothelial cells, numerous neutrophils, and abundant nuclear dust; these features were diagnostic for bacillary angiomatosis. The diagnosis was confirmed by the Grocott-Gomori methenamine-silver nitrate stain that revealed argyrophilic bacteria and by ultrastructural demonstration of bacillary structures with trilaminar walls. Treatment with clarithromycin led to complete resolution of the lesions within 4 weeks. CONCLUSIONS: This case emphasizes that (1) bacillary angiomatosis must be considered in the differential diagnosis of vascular lesions in immunocompromised patients without human immunodeficiency virus infection, (2) Grocott-Gomori methenamine-silver nitrate stain is a simple and satisfactory alternative to the Warthin-Starry stain for the demonstration of bacilli in this condition, and (3) clarithromycin is an effective oral antibiotic for the treatment of this disease.

[Cutaneous apocrine mixed tumor with follicular differentiation]. / Apokriner kutaner Mischtumor mit follikulärer Differenzierung.

An 85-year-old man presented with a firm, papillomatous nodule on the upper lip, which had been growing slowly for 30 years. Histopathologic examination revealed an apocrine mixed tumour with follicular differentiation. Mixed tumours of the skin are rare benign neoplasms, which are composed of different tissue components, e.g. epithelial and glandular elements and myxoid or chondroid components. Mixed tumours with apocrine differentiation can be discriminated from mixed tumours with eccrine differentiation. Criteria for apocrine differentiation are: decapitation secretion, elongated gland-like and duct-like structures lined with two rows of epithelial cells and branching of tubular structures. Follicular structures are another clue to the apocrine differentiation of neoplasms. The designation mixed tumour is preferable to chondroid syringoma, because most mixed tumours show apocrine differentiation. The differential diagnosis of apocrine mixed tumour includes fibroadenoma, hidradenoma, mucinous adenocarcinoma, adenoid cystic carcinoma, and rare soft tissue tumours like the myxoid chondrosarcoma.

Acquired relapsing self-healing Blaschko dermatitis.

We describe a 44-year-old woman who had a unilateral relapsing linear dermatosis for 12 years. The lesions consisted of erythematous, discrete and grouped papules and papulovesicles that were localized to the left side of the upper and lower limbs, chest, abdomen, and back. They were distributed along Blaschko's lines. There was also a diffuse erythematous scaly hyperkeratosis of both palms. The lesions healed spontaneously. Examination of biopsy specimens from the back and the left palm revealed acute and subacute spongiotic dermatitis, respectively. This dermatosis was first described by Grosshans and Marot in 1990 and termed "Blaschkite de l'adulte." Because the disease is acquired, relapsing, heals spontaneously, follows Blaschko's lines, and is characterized histopathologically by a spongiotic dermatitis, we propose the term "acquired relapsing self-healing Blaschko dermatitis."