Magnetic vortex core reversal by excitation with short bursts of an alternating field

The vortex state, characterized by a curling magnetization, is one of the equilibrium configurations of soft magnetic materials and occurs in thin ferromagnetic square and disk-shaped elements of micrometre size and below. The interplay between the magnetostatic and the exchange energy favours an in-plane, closed flux domain structure. This curling magnetization turns out of the plane at the centre of the vortex structure, in an area with a radius of about 10 nanometres--the vortex core. The vortex state has a specific excitation mode: the in-plane gyration of the vortex structure about its equilibrium position. The sense of gyration is determined by the vortex core polarization. Here we report on the controlled manipulation of the vortex core polarization by excitation with small bursts of an alternating magnetic field. The vortex motion was imaged by time-resolved scanning transmission X-ray microscopy. We demonstrate that the sense of gyration of the vortex structure can be reversed by applying short bursts of the sinusoidal excitation field with amplitude of about 1.5 mT. This reversal unambiguously indicates a switching of the out-of-plane core polarization. The observed switching mechanism, which can be understood in the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application in data storage.

Laterality of hand, foot, eye, and ear in twins

Information on handedness, footedness, eyedness, and earedness was collected from 33 monozygotic (MZ) twin pairs and 67 dizygotic (DZ) twin pairs. The incidence of nonright-sidedness in the twins is not higher than that reported in the literature for singletons. Similar results are found for the other lateralities. The results of assessing handedness with preference tests do not differ from those carried out with performance tests. There are no differences in incidence of nonright-sidedness between MZ and DZ twins. The concordance of lateralities is similar in MZ and DZ twins. The proportions of Right-Right, Right-Nonright, and Nonright-Nonright pairs in both groups of twins show a binomial distribution. The present results do not confirm a genetic hypothesis of determination of sidedness in humans and are comparable with the results obtained by other twin studies.

Analysing a magnetic molecule detection system--computer simulation

The detection of single molecules, e.g. in biology is possible by marking the interesting molecules with magnetic beads and detect the influence of the beads on giant magnetoresistance (GMR)/tunnel magnetoresistance (TMR)/spin valve (SV) sensors. The development of suitable multilayers has been studied experimentally as well as theoretically in order to optimize the sensor parameters. A finite difference (FD) method including the usually used contributions to the total energy [exchange, antiferromagnetically (af) coupling, anisotropy and magnetostatic] is used for the simulation with additional contributions to the local field according to the stray fields of the beads. In this work, we will show the results of micromagnetic calculations of the magnetization behavior of GMR/TMR sensors considering also the interaction between the domains in the magnetic layers of the sensor and the bead area. We can present first calculations where the bead particles (signal source) and the magnetic layers (sensor device) are considered as a whole magnetic ensemble.

Detection and manipulation of biomolecules by magnetic carriers

The detection and manipulation of single molecules on a common platform would be of great interest for basic research of biological or chemical systems. A promising approach is the application of magnetic carriers. The principles are demonstrated in this contribution. It is shown that paramagnetic beads can be detected by highly sensitive magnetoresistive sensors yielding a purely electronic signal. Different configurations are discussed. The capability of the sensors to detect even single markers is demonstrated by a model experiment. In addition, the paramagnetic beads can be used as carriers for biomolecules. They can be manipulated on-chip via currents running through specially designed line patterns. Thus, magnetic markers in combination with magnetoresistive sensors are a promising choice for future integrated lab-on-a-chip systems.

[The new features of the bibliography database manager EndNote 6.0 and 7.0]

The bibliography database manager EndNote shows since 1999 a dramatically technical development. A new improved version is published every year. Because the version 7.0 was recently (June 2003) released, we want to describe some aspects of the new version. We also would like to examine, for which user the use of the respective version is recommendable. The use of the software package EndNote 6.0 and also 7.0 for Windows is described. The main reason for getting Endnote 6 is its clearly improved functions and features: Organize a variety of charts equations or pictures and the use of Microsoft-templates. The version 7.0 can be recommended especially to scientist who much works with a Palm particularly. It is also possible to work not only with Microsoft-Word but also with other word processors and creating a bibliography with topic headings. Altogether EndNote 6.0 and also 7.0 provides an excellent combination of features and ease of use. The versions 6.0 or 7.0 are useful especially for people, who every single day use EndNote. EndNote 7.0 is for user of a Palm a special recommendable version.

Comparison of a prototype magnetoresistive biosensor to standard fluorescent DNA detection

We present a comparative analysis of a magnetoresistive biosensor to standard fluorescent DNA detection. The biosensor consists of giant magnetoresistive (GMR) type Cu/Ni(80)Fe(20) multilayers in the second antiferromagnetic coupling maximum. Each of the 206 elements of the magnetoresistive biosensor is patterned into a spiral-shaped line that can cover the area of a typical DNA spot (70 microm diameter). The probe DNA is assembled on top of the sensor elements in different concentrations ranging from 16 pg/microl to 10 ng/microl. Complementary biotin-labeled analyte DNA is hybridized to the probe DNA at a concentration of 10 ng/microl. A number of different commercially available magnetic microspheres are investigated to determine the most appropriate markers. The experimental comparison shows that the relative sensitivity of the magnetoresistive biosensor is superior to the fluorescent detection at low probe DNA concentrations.

Absence of intrinsic electric conductivity in single dsDNA molecules

The intrinsic dc conductivity of long, individual lambda phage dsDNA molecules has been investigated by ultrasensitive low current-voltage-spectroscopy (IV) under ambient conditions and controlled low humidity inert gas atmosphere on microfabricated metal-insulator-metal gap structures. We found a strong dependence of the measured conductivity on the apparent humidity, which we attribute to capillary condensation of water to the immobilized DNA molecules, giving rise to additional ionic currents. Additional IV-spectroscopy experiments under controlled argon atmosphere always revealed a significant drop in electrical conductivity to 4 x 10(-15)AV(-1)microm(-1), indicating almost no considerable contribution of electrical long range charge transport.

[Burning mouth syndrome--etiology, differentialdiagnostical aspects and therapy]

Burning Mouth Syndrome (BMS) or glossodynia is a chronic pain syndrome that mainly affects middle-aged/elderly women. This condition is probably of multifactorial origin, often idiopathic, and its etiopathogenesis remains largely enigmatic. Visible pathologic lesions of the oral mucosa or processes are usually not evident. Etiologic factors that have been reported include several disorders (e. g. hematologic disorders, denture factors, the climacteric, infections, endocrinological, neurological or psychiatric disorders). On the other hand psychological factors, such as anxiety, depression and phobias have been reported to play a significant role at the beginning of this nosological entity. BMS related to nutritional deficiency is uncommon. A systemic approach to assessment is essential and the opinion of other specialities, particularly internal medicine, dentistry or neurology, may be of help. Treatment is of the underlying cause but in many cases no specific aetiological factor is identified. Non-indicated substitution therapy of suspected but unproved deficiency states must be avoided. Treatment approaches were divided into topical and systemic strategies. However, there is little research evidence that provides clear guidance for those treating patients with BMS.

Review article: hepatitis vaccination in patients with chronic liver disease

Evidence regarding the outcomes of viral super-infection in patients with chronic liver disease and practical strategies for hepatitis A and B vaccination of these individuals are reviewed. Patients with acute hepatitis A and chronic hepatitis B have a more severe clinical course and a higher death rate compared with otherwise healthy individuals with hepatitis A, and these differences are most pronounced in older patients and those with histological evidence of chronic hepatitis or cirrhosis, rather than in asymptomatic hepatitis B carriers. Patients with acute hepatitis A super-infection and chronic hepatitis C have an increased risk of fulminant hepatitis and death. In addition, patients with other chronic liver diseases also appear to be at increased risk for more severe disease with superimposed hepatitis A. Patients with chronic hepatitis B and hepatitis C virus co-infection have more severe laboratory abnormalities, more severe histological disease, a greater frequency of cirrhosis and complications of cirrhosis, and a higher incidence of hepatocellular carcinoma. Vaccines for both hepatitis A and B are safe and effective if used early in the course of chronic liver disease. Hepatitis A and B vaccination should be part of the routine management of patients with chronic liver disease, preferably as early as possible in the natural course of their disease.

Loss of BRCA2 correlates with reduced long-term survival of sporadic breast cancer patients

BACKGROUND

The present study was undertaken to analyze the prognostic value of loss of heterozygosity (LOH) at 13q12-13, 17q21 and 17p13, harboring BRCA2, BRCA1 and p53 to predict the clinical course of sporadic breast cancer patients.

MATERIALS AND METHODS

LOH analysis was performed by PCR amplification of genomic DNA using nine microsatellite markers. Fifty-three sporadic breast cancer patients were followed clinically for a median of 55 months. Disease-free and overall survival was documented as the endpoint for statistical evaluation.

RESULTS

Patients presenting with LOH in their tumor samples at at least one of the loci examined were found to have a reduced overall survival time compared to those retaining heterozygosity (61% versus 48%). Focusing on the three target regions, patients with LOH at the BRCA2 locus died earlier compared to patients retaining heterozygosity (69% versus 50%) and, in addition, BRCA2 LOH-positive patients showed a shorter metastasis-free interval (30 versus 37 months). In a multivariate analysis, LOH at the 13q12-13 locus was found to be a significant predictor for reduced long-term survival (risk ratio 2.33, 95% C.I., 1.0-5.3; p<0.05) and earlier metastases manifestation (risk ratio 2.32, 95% C.I., 1.0-5.3, p<0.05).

CONCLUSION

Allelic loss at the BRCA2 locus may be of use as a negative predictor for metastases-free and overall survival.

3-O-methyl-6-[18F]fluoro-L-DOPA and its evaluation in brain tumour imaging

3-O-Methyl-6-[(18)F]fluoro-L-DOPA (OMFD) is a major metabolite of 6-[(18)F]fluoro-L-DOPA. Although synthesis of OFMD was primarily established to study the dopaminergic system, as it is an amino acid analogue, uptake in experimental tumours has been found. The aim of this study was to evaluate the applicability of OMFD for brain tumour imaging and to obtain initial estimates of whole-body biodistribution and radiation dosimetry in humans. Nineteen patients with suspected or confirmed brain tumours were investigated with OMFD and dynamic brain PET, complemented by whole-body PET in seven patients. Tracer kinetics were compared for normal brain and intracerebral lesions. Tissue accumulation was quantified with standardised uptake values (SUVs). Whole-body distribution in combination with tracer kinetics from animal experiments was used for the calculation of radiation dosimetry data. On the basis of OMFD PET, viable brain tumour was suspected in 16 patients with SUVs of 3.0+/-0.8 and a tumour to non-tumour ratio of 1.9+/-0.5. Highest tumour and normal brain uptake occurred between 15 and 30 min, with a subsequent slow decrease. Late whole-body tracer distribution was uniform without specific organ accumulation. Elimination occurred via urine. The mean radiation dose to the whole body was estimated at 0.016 mSv/MBq, with the kidneys as dose-critical organ (0.033 mGy/MBq). In conclusion, OMFD enables the visualisation of brain tumours with SUVs similar to other fluorinated amino acids. The whole-body radiation exposure from OMFD is comparable to that from FDG imaging.

Comparison of functional brain PET images and intraoperative brain-mapping data using image-guided surgery

OBJECTIVE

Knowledge about the spatial localization of eloquent brain areas is essential for resecting lesions in the vicinity of these areas. The classical approach is to perform surgery on the awake patient under local anesthesia using brain-mapping techniques. As an alternative, the location of eloquent areas can be visualized by preoperative functional brain-imaging techniques, for example, positron emission tomography (PET), functional magnetic resonance imaging (fMRI), or magnetoencephalography (MEG). Using functional activation PET, both methods were combined by integration into a frameless navigation system (BrainLAB) and used to map speech-eloquent areas.

PATIENTS AND METHODS

Speech-eloquent areas were localized preoperatively in seven patients with a left-sided glioma using 2-[(18)F]-2-desoxy-D-glucose PET. Patients were scanned under silence conditions (i.e., with the patient remaining silent in a sound-proof cabin), and speech was activated using a verb-generation paradigm. The PET data were transferred to the neuronavigation workstation and matched with a preoperative 3D-MRI using an automatic image-fusion algorithm. Intraoperative speech localization was performed using brain-mapping techniques under local anesthesia with bipolar cortical stimulation. The stimulator position was mapped into the MRI/PET data set by neuronavigational tracking of the instrument.

RESULTS

Functional PET images were integrated into the MRI-based neuronavigational system and could be transferred exactly to the operative field. By the additional integration of cortical stimulation, intraoperative electrophysiological findings can be directly compared with preoperative functional images. Seven patients with left-sided glioma were operated on using this protocol, confirming the technical feasibility. In three of seven patients, preoperative PET findings were not supported by intraoperative mapping.

CONCLUSIONS

This matching and mapping technique is suitable for monitoring eloquent speech areas during surgical resection of extensive left-sided low-grade gliomas, allowing a direct comparison between intraoperative electrophysiological brain mapping and preoperative functional brain-imaging findings. The sensitivity and specificity of functional imaging techniques can now be evaluated by reconciling the data with the intraoperative stimulation results.

[Manual lymph drainage as therapy of edema in the head and neck area]

Depending on its genesis, edema must be treated by medication or diet. Simultaneous application of lymph drainage may be beneficial in some cases, especially in combined edema. The manual lymphdrainage is a special method of massage. In some kinds of edema, in particular lymphedema, only therapeutic lymph drainage introduced into medicine by Vodder, Asdonk and Kuhnke can attain an improvement, since there is no drug which acts on the lymphatic system. We report about primary and secondary lymphedemas of the face and head. Secondary lymphedemas are a result of surgical therapy, cancer therapy, irradiation or are caused of tumors or their metastases respectively. Depending on the state of the edema a lymphatic drainage treatment is indicated palliatively.

[Ototoxicity of aminoglycoside antibiotics]

In gram-negative infections aminoglycosides still remain to present a first-line antibiotic. Their use is limited by the high risk for side effects and especially nephrotoxicity and ototoxicity. The more recently developed members of this group, although purporting to be less ototoxic, are also capable of producing inner ear damage in sufficiently high doses. This paper reviews the morphological, histochemical, and electrophysiological evidence concerning the mode of action of aminoglycosides on the auditory and vestibular systems and discusses the available methods for the detection of possible clinical ototoxicity. With recent advances in aminoglycoside monitoring techniques, the risk of toxicity has been greatly reduced. Guidelines are proposed about the prevention of ototoxicity and the management of patients with established auditory or vestibular dysfunction.

Surgery of low-grade gliomas near speech-eloquent regions: brainmapping versus preoperative functional imaging

The identification of eloquent areas is of utmost importance in the surgery of tumors located near speech-eloquent brain areas, since the classical concept of a constant localization was proven to be untrue and the spatial localization of these areas may show large interindividual differences. Some neurosurgical centers apply intraoperative electrophysiological methods that, however, necessitate the performance of surgery in the awake patient. This might be a severe burden both for the patient and the operating team in a procedure that lasts several hours; in addition, electrical stimulation may generate epileptic seizures. Alternatively, methods of functional brain imaging (e.g., PET, fMRI, MEG) may be applied, which allow individual localization of speech-eloquent areas. Matching of these image data with a conventional 3D-CT or MRI now allows the exact transfer of this information into the surgical field by neuronavigation. Whereas standards concerning electrophysiological stimulation techniques that could prevent a permanent postoperative worsening of language are available, until now it remains unclear whether the resection of regions shown to be active in functional brain imaging will cause a permanent postoperative deficit.

[EndNote 5 reference manager--functions--improvements--personal experiences]

Bibliography database managers are used to manage information recourses: specifically, to maintain a database to references and create bibliographies and reference lists for written works. A good reference management program should make it easy to read and to record the elements that a reference comprises, e.g. authors name, year of publication, title of article etc. It should offer tools that let you find and retrieve references quickly, and it should be able to produce the bibliography in the format required for a particular publication. You can create your database reference by reference or you can download batches of references from one of the popular searching services (e.g. MEDLINE) and you can search in the Internet. When you want to cite a reference you simply paste the reference wherever you want your intext citation to appear. There are many computer programs, but very few stands out as truly useful, time saving, and work enhancing. One of them is EndNote. The reference manager EndNote 5.0 was recently released in Germany. As long-time fans of this excellent program, we upgraded from the previous version. The use of the software package EndNote 5.0 for Windows is described. The main reason for getting EndNote 5.0 is its clearly improved functions and features: especially the co-operation with Microsoft Word (cite while you write) and the spelling examination. Altogether EndNote 5.0 provides also an excellent combination of features and ease of use.

[Ear drops--therapeutic aspects and application]

Ear drops are widely used in the topical treatment of inflammatory disorders of the external meatus and the eardrum. This paper gives some aspects of the therapeutic effects and installation of ear drops. The role of topical ear drops as a possible cause of ototoxicity is reviewed. Although experimental data confirm the presence of ototoxicity due to topical ear drops, the clinical relevance still remains debatable. The fact that currently used ear drops may produce a sensorineural hearing loss should not be ignored.

[Diagnosis of allergic rhinitis]

Allergic diseases remains an important problem that affects people of all ages. The prevalence of allergic rhinitis amounts to 10 to 16% in Central Europe with a tendency to be on the rise. Allergic rhinitis constitutes one of the commonest causes for visits to a general practitioner. Correct diagnosis is important for optimal management. A thorough history should be taken, followed by general and endoscopic examinations and confirmatory investigations. Careful examination should reveal obvious alternative causes of symptoms, such as polyps or tumours. If allergy is suspected, this can be confirmed by further tests, particularly the skin-prick test, measurements of serum specific IgE, the nasal provocation test of allergens or zytological examination.

[Rhinitis in old age]

The chronic rhinitis is a frequent problem with age. In the nose, normal physiologic changes of aging include loss of nasal tip support, atrophy of mucus-producing mucosal glands, and decreased olfaction. The fragmentation and weakening of the cartilage of the septum also causes airflow changes contributing to nasal stuffiness. These changes contribute to geriatric rhinitis, the symptoms of which are often attributed by the older patient to "allergies" or "sinus trouble". An understanding of these anatomic changes, linked with a thorough history and physical examination, allows the physician to properly manage geriatric rhinitis. Earnest causes like tumors or mycosis must be excluded. The treatment depends on the etiology of the rhinitis and also the symptoms of the patient. Therapy includes avoidance of all sorts of allergens (dust, fumes, sprays) and appropriate attention to minimizing home environmental and occupational exposures. Pharmacotherapy most often involves liquifying--not drying--nasal secretions with oral and topical preparations. Conservative surgical treatment is occasionally indicated.

[Why 2 ears?]

Having two ears instead of just one is advantageous in several respects. The danger of deafness is decreased, the auditory field is enlarged, spatial perception is possible on the basis of binaural disparities. Auditory deprivation presents as loss of discrimination over time in the unaided ear of individuals with a unilateral hearing loss. Earedness and ear preference ensure the choice of the dominant ear for definite actions like eavesdropping, telephone or listen.