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Notes: Over the last decade, x-ray magnetic circular dichroism (XMCD) and x-ray resonant magnetic scattering (XRMS) have become important experimental techniques in the study of magnetic materials. In order to reduce systematic errors in these measurements, typical XMCD and XRMS experiments are carried out using magnetization switching, although there are many situations where polarization switching is clearly desirable. Recently, fast polarization modulation techniques have been developed using either polarization conversion optical elements, such as phase plate, or special insertion devices. At the National Synchrotron Light Source (NSLS), an elliptically polarized wiggler (EPW), jointly developed by NSLS, Advanced Photon Source, and BINP of Novosibirsk, for this purpose. The EPW consists of a permanent magnet vertical wiggler and an electromagnet horizontal wiggler. The polarization of the device can be switched up to 100 Hz by switching the electromagnet. To take advantage of the fast switching capability, a phase sensitive detection system was also implemented. The sensitivity of using fast polarization modulation is demonstrated by measuring the element specific hysteresis loop and MCD spectrum of Cu induced moment at the interface of a Co/Cu multilayer. By comparing with results obtained using conventional measurements from similar samples, it clearly shows the advantages of using polarization modulation for small MCD effects. The sensitivity of this technique and the possibility of performing magnetic field dependent measurements of using polarization modulation have been applied to a number of magnetic systems. First, the spatial distribution of Cr induced moment in an ideal exchange-biased Fe/Cr multilayer was measured using soft-x-ray XRMS. Specular reflectivity was measured as a function of both angle and energy near Cr and Fe L3 edges. The Cr induced moment was clearly observed. Moreover, the spatial distribution of the induced Cr moment was determined by combining the measurements with detailed simulation of the energy and angle dependent specular reflectivity. Second, the magnetic behavior and spatial distribution of the interfacial Ni spins in an exchange-biased Co/NiO bilayer were studied using angle and energy dependent specular reflectivity as well as total electron yield. These results will be discussed in relation to several existing models of interface spin structures for exchange bias. Other applications of polarization modulation will also be discussed. © 2002 American Institute of Physics.

Notes: A serious problem of high-power GaAs/AlGaAs laser diodes is the strong mirror heating, which is caused by the carrier density and the correlated nonradiative surface recombination at the cleaved mirrors. Therefore the top electrode was segmented in three parts and the influence of a separate controllable potential in the mirror region on the temperature has been studied. The local temperature was measured using spatially resolved Raman scattering. A substantial reduction of the mirror temperature is possible by applying a suitable potential to the mirror contacts. This may lead to an improvement in reliability in the case where the high mirror temperature is responsible for the degradation of the laser.

Notes: On 7 May 1993, a 9-month-old baby boy was referred to the Pediatric Outpatient Clinic of the University Department of Dermatology in Trieste. For 8 months he had been suffering from a relapsing multiple annular erythema. Physical examination revealed a generalized, asymmetric, elevated, urticarial erythema characterized by arched, ring-shaped polycyclic patches (Fig 1). Furthermore, the infant had a generalized lymphoadenopathy, but no other general symptoms were found. The baby's parents reported that the lesions had first appeared 3 weeks after birth, had regressed spontaneously in 2–3 weeks, and had relapsed four times before our observation. The lesion-free periods between the relapses had become shorter and shorter and the clinical manifestations had become more and more serious. Fever (about 39°C), which had accompanied the cutaneous eruptions, had disappeared during the first day.A skin punchbiopsy specimen was taken from a lesion for histologic examination and polymerase chain reaction (PCR). The biopsy was formalin fixed and paraffin embedded. Microscopic examination demonstrated no changes in the epidermis, and a superficial and deep perivascular, periadnexial, and interstitial infiltrate composed of lymphocytes with spare plasma cells and some neutrophils. Modified Warthin-Starry silver stain applied to paraffin sections showed numerous spirochetal bodies strongly resembling Borrelia burgdorferi (Bb) in epidermis and dermis. After histologic examination, five tissue sections of 6–8 μm were cut from each paraffin block and deparaffinized, rehydrated, and digested with proteinase K. The deoxyribonucleic acid (DNA) was extracted and precipitated.2 A sequence of about 80 bases related to the Bb flagellin protein was PCR amplified, using a very long amplification to avoid any risk of carry-over.2 False positive results were avoided by applying the precautions suggested by Kwok et al.3 Negative controls consisted of parallel extractions and amplifications from paraffin blocks without any tissue and with healthy skin. For the positive control, DNA extracted from Bb culture was used. Southern blot was performed to check the specificity of the amplification. After the PCR analysis, the patient presented a positive amplification for the flagellin sequence.Serologic testing for Lyme borreliosis (LB) was performed by the enzyme-linked immunosorbent assay (ELISA) using Bdflagellum as antigen, and by the immunofluorescence (IF) assay using a commercial kit which included preadsorption of the patient's serum with Treponema phagedenis. Serum for LB Western blot antibody was obtained. Serologic studies revealed LB immunoglobulin M (IgM) and immunoglobulin G (IgG) negative antibodies by indirect immunofluorescence (IFI) and flagellum ELISA. Western blotting was also negative.The patient had a negative history for tick bites and had not taken any drug before the onset of skin lesions. Laboratory findings were not contributory: the erythrocyte sedimentation rate was slightly elevated (24 mm), but all the other routine tests were normal. The IgM rheumatoid factor and antinuclear antibodies were absent. No cryoglobulins were identified. Serology for syphilis (venereal disease research laboratory (VDRL) and Treponema pallidum hemagglutination) was also negative. Assays for antibodies to toxoplasmosis, mononucleosis, rubella, cytomegalovirus, and herpes simplex, afetoprotein determination, and genetic evaluation were unrevealing. Bacterial growth was not revealed in blood culture. No pathogens were identified through urine culture.Electrocardiogram(ECG), echogram of the heart and abdominal organs. X-ray of the chest, and neurologic and ophthalmologic examination showed no pathologic results.The mother, a 32-year-old woman, had not recalled any tick bite and had had no symptoms during pregnancy, but she had taken part in outdoor activities in an area in the northeast of Italy known to be endemic for LB.4 Since there had been no suspicion of Bb infection during pregnancy, serologic tests for LB had not been performed. At the 39th week, after an uneventful pregnancy, she gave birth to a healthy male infant. When we observed her son, she was investigated by IFI for IgM and IgG titers against Bb antigen. The serum antibody titer to Sfa was slightly high (IgG, 1:128; cut-off, 1:64). Treponema pallidum hemagglutination was negative.We treated the baby with oral josamycin, 250 mg twice a day for 14 days, and after 1 week the lesions had disappeared.Three months later, numerous papular erythemato-edematous lesions, pink in color and about 3–4 mm in diameter, resembling a strophulus, were present on the arms and legs. Treatment with josamycin, 350 mg twice a day for a further 14 days, heaied the lesions. A month later, another eruption of papular lesions, a diffuse lymphoadenopathy, and a bluishred discoloration appeared in the legs. Serum for LB IFI, ELISA, and Western blot antibodies was obtained. Antibodies to 6b could not be detected by IFI and ELISA, but Western blot assay was positive in the IgG class: a band of reactivity with Borrelia garinii with a molecular weight of 41 kD was observed, together with three strong bands of reactivity with both Bb sensu stricto and Borrelia afzeliiaX 30, 41, and 61 kD.The patient received a 14-day course of amoxiciliin, 800 mg in three oral doses daily. At the following observation, 1 month later, no lesions were found.When the chiid was 2 years of age, a multiple annular erythema appeared again. Generalized lymphoadenopathy was also present. The patient received a 14-day course of amoxiciliin, 1 g in three oral doses daily, and, subsequently, a 21-day course of josamycin, 500 mg twice a day orally. The skin lesions resolved after a few days and, at the end of the treatment, lymphoadenopathy had also disappeared.One year later, a multiple annular erythema and a generalized lymphoadenopathy appeared again. A biopsy from a skin lesion was aseptically ground and inoculated in Barbour Stoeuner Kelly II medium. The culture was incubated at 34°C and checked under a dark field microscope to verify the presence of spirochetes at 3-day intervais. After 10 days, some spirochetes with the typical morphology of Borreliae were observed under the microscope. Subcultures which were performed from this tube did not develop any growth of Borreliae during the time of observation (1 month). The patient again received a 14-day course of amoxiciliin, 1 g in three oral doses dally, and, subsequently, a 21-day course of josamycin, 500 mg twice a day orally, which resulted in a rapid resolution of the lesions.The child, now 4 years of age, has no lesions and shows normal anatomic and functional development.

Notes: A 39-year-old woman, had a lesion on her right thigh that first developed when she was 6 weeks old. This lesion was said to have resembled “spider bites,” and was initially treated with cryotherapy. It continued to enlarge and was biopsied in May 1969, when she was 13 years old. The patient was told she had “neurofibroma.” In 1971, the lesion was rebiopsied and a question of a sarcoma was raised in the pathology report. She underwent extensive surgery to remove the lesion, requiring a skin graft at the operation sife. Multiple lesions subsequently developed around her graft. Biopsies of several lesions were interpreted as dermatofibroma, and she was referred to the Indiana University, Department of Dermatology. When seen in 1995, she had a well-healed 30 cmx14 cm hypopigmenfed split-thickness skin graft present on the lateral right thigh. The margin of the graft was outlined by multiple red-brown firm papules and plaques. Some of the papules and plaques extended beyond the margin of the graft by several centimeters (Fig. 1). Histopathology of the satellite lesions showed epidermal hyperplasia and diffuse spindle cell proliferation in the upper and lower dermis (Fig. 2). The majority of the spindle cells stained positively for Factor Xllla (a marker for dermal dendrocytes). They did not stain with CD34 (a marker for dermatofibrosarcoma protuberans).