Imaging of super-fast dynamics and flow instabilities of superconducting vortices.

Quantized magnetic vortices driven by electric current determine key electromagnetic properties of superconductors. While the dynamic behavior of slow vortices has been thoroughly investigated, the physics of ultrafast vortices under strong currents remains largely unexplored. Here, we use a nanoscale scanning superconducting quantum interference device to image vortices penetrating into a superconducting Pb film at rates of tens of GHz and moving with velocities of up to tens of km/s, which are not only much larger than the speed of sound but also exceed the pair-breaking speed limit of superconducting condensate. These experiments reveal formation of mesoscopic vortex channels which undergo cascades of bifurcations as the current and magnetic field increase. Our numerical simulations predict metamorphosis of fast Abrikosov vortices into mixed Abrikosov-Josephson vortices at even higher velocities. This work offers an insight into the fundamental physics of dynamic vortex states of superconductors at high current densities, crucial for many applications.Ultrafast vortex dynamics driven by strong currents define eletromagnetic properties of superconductors, but it remains unexplored. Here, Embon et al. use a unique scanning microscopy technique to image steady-state penetration of super-fast vortices into a superconducting Pb film at rates of tens of GHz and velocities up to tens of km/s.

Velocimetry of superconducting vortices based on stroboscopic resonances.

An experimental determination of the mean vortex velocity in superconductors mostly relies on the measurement of flux-flow resistance with magnetic field, temperature, or driving current. In the present work we introduce a method combining conventional transport measurements and a frequency-tuned flashing pinning potential to obtain reliable estimates of the vortex velocity. The proposed device is characterized using the time-dependent Ginzburg-Landau formalism, where the velocimetry method exploits the resonances in mean vortex dissipation when temporal commensuration occurs between the vortex crossings and the flashing potential. We discuss the sensitivity of the proposed technique on applied current, temperature and heat diffusion, as well as the vortex core deformations during fast motion.

Stroboscopic phenomena in superconductors with dynamic pinning landscape.

Introducing artificial pinning centers is a well established strategy to trap quantum vortices and increase the maximal magnetic field and applied electric current that a superconductor can sustain without dissipation. In case of spatially periodic pinning, a clear enhancement of the superconducting critical current arises when commensurability between the vortex configurations and the pinning landscape occurs. With recent achievements in (ultrafast) optics and nanoengineered plasmonics it has become possible to exploit the interaction of light with superconductivity, and create not only spatially periodic imprints on the superconducting condensate, but also temporally periodic ones. Here we show that in the latter case, temporal matching phenomena develop, caused by stroboscopic commensurability between the characteristic frequency of the vortex motion under applied current and the frequency of the dynamic pinning. The matching resonances persist in a broad parameter space, including magnetic field, driving current, or material purity, giving rise to unusual features such as externally variable resistance/impedance and Shapiro steps in current-voltage characteristics. All features are tunable by the frequency of the dynamic pinning landscape. These findings open further exploration avenues for using flashing, spatially engineered, and/or mobile excitations on superconductors, permitting us to achieve advanced functionalities.

Why Croatian patients increasingly opt for treatment in private medical clinics?

The professional conduct of medical professionals should be a guarantee to the citizens of Croatia that, if they become patients, their medical institutions, regardless of whether they are private or state-owned, will provide them with a good-quality and timely medical care. Efficient organization of medical care depends on the entire medical community, and patient's satisfaction is a result of its members' interaction. Unacceptably long waiting lists, preoccupied primary care doctors, insufficient quantities of drugs and financial resources make the functioning of public medical institutions difficult. The objective of this article is to assess the reasons why patients opt for treatments in privately owned medical centers. The survey has been conducted in February 2008 on 200 patients of one privately owned health institution in Zagreb. The questionnaire consisting of 13 questions, compared different aspects of treatment in private and public health care institutions. Answers pointed out that three most frequent difficulties the patients meet while being treated in public institutions are long waiting lists for examination or surgery, too long waiting times in outpatient clinics, and indifference of the medical staff. The average grade of satisfaction with treatment is 4.57 in public institutions and 8.89 in private institutions (Tab. 8, Ref. 14).

Predictive value of assessment of disc-radicular conflict of the cervical segment by somatosensory evoked potentials.

Somatosensory evoked potentials (SSEP) of the n. medianus, with clinically significant neurological findings helps in diagnosing a number of different cervical spine lesions. SSEP of the n. medianus and neurological observations also aid in diagnosticis of the disc-radicular conflict. A final diagnosis is set by the computerised tomography (CT). The tested positive predictive value of assessment of disc-radicular conflict of the cervical spine by means of SSEP is 87%. The 95% confidence interval (CI) is 0.87 (0.81-0.93) (Tab. 3, Fig. 4, Ref. 23). Full Text (Free, PDF) www.bmj.sk.

Alzheimer's disease patients: quality of life in the Republic of Croatia.

The most common among dementias is Alzheimer's disease (AD). At the beginning it is controllable by medications but, as the disease advances, the patient needs a 24-hour care and very often one family member has to devote him/herself to the permanent care of the ill. AD dictates both patient's and family member's lives. The illness demands routine, patient behaviour, adjustments in living conditions as well as a lot of sacrifice. Although AD patients need adequate care in medical and social institutions, the caregiver's role is crucial. Therefore, the care for AD patients implicates the care for family members, i.e. caregivers. Such care should consist of medical care to caregivers, joint planning of the progress of illness and full daily patient care as well as legal advice. Croatia still hasn't got a fully developed care system for neither of the participants in the Alzheimer's disease (Ref. 22). Full Text (Free, PDF) www.bmj.sk.

Lamotrigine in the treatment of pain syndromes and neuropathic pain.

Anti-epileptic drugs are increasingly used in the treatment of pain syndromes and neuropathic pain. Sodium channel blockers can be effective in the treatment of pain. The object of our interest is the efficiency of lamotrigine in treating the pain. A MEDLINE search was conducted to identify pertinent studies, case reports, letters, and reviews in English published from 1986 to May 2007. The search has indicated efficiency in treating a number of painful syndromes and neuropathic pain; central pain, trigeminal neuralgia and trigeminal neuralgia in multiple sclerosis, pain in multiple sclerosis, SUNCT syndrome, cluster headache, glossopharyngeal neuralgia, neuropathic pain, allodynia, neuralgia after nerve section, postherpetic neuralgia, HIV-associated neuropathy. Further researches are required on the role of lamotrigine in treating the spinal cord injury pain, neuralgia after nerve section, postoperative analgesic requirement, and in migraine (Tab. 1, Ref. 46). Full Text (Free, PDF) www.bmj.sk.

Spondylodiscitis.

Spondylodiscitis is the most common complication of sepsis or local infection, usually of an abscess. Very often it develops in patients immunocompromised by a malignant disease, infection, or during immunosupression for organ transplantations etc. Presently, the basic diagnostic examinations to establish spondylodiscitis are the magnetic resonance (MRI) and biopsy, with microbiological tests. Lately, infection causes are increasingly proven by PCR method. In this paper we describe the causes of spondylodiscitis by reviewing the existing literature. The main causative organisms are staphylococci and Mycobacterium tuberculosis. The causes of spondylodiscitis are assigned to a large number of bacteria, fungi, zoonoses, which is to be taken into consideration in diagnostic treatment of patients (Ref. 51). Full Text (Free, PDF) www.bmj.sk.

An acute headache and hydrocephalus caused by the dermoid cyst.

We present a case report of a 41-year-old man with an acute headache and hydrocephalus caused by the dermoid cyst. The dermoid cyst of the third brain ventricle caused an acute hydrocephalus and an increased intracranial pressure (with neurological signs such as nausea, vomiting, oedema papilae n. optici) and, consequently, an acute intensive headache. Computed tomography scans demonstrated a mass in the third ventricle extending into the prepontine cistern, whereas any initially established cerebrospinal fluid ventriculoperitoneal shunt required further revision (Fig. 2, Ref. 12). Full Text (Free, PDF) www.bmj.sk.

Spectrophotometric assay of xanthine oxidase with 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) (ABTS) as chromogen.

A new method for the determination of xanthine oxidase activity, based on the oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) (ABTS) by use of uricase and peroxidase, is described. The absorbance increase of the oxidized form of ABTS, measured after 10 min at 410 nm is proportional to xanthine oxidase activity. The method is sensitive, precise (CV below 8.3%), and linear up to 20 U/l. The analytical recovery of the ABTS-method was quantitative. Comparison with the UV and colorimetric NBT-method gave good correlation (r greater than or equal to 0.984). Reference values for serum xanthine oxidase activities determined with the new ABTS-method on 83 healthy persons are 0 to 1.20 U/l.

Effects on analgesic and antirheumatic drugs on the assay of serum enzymes.

Interference by some commonly used analgesic and antirheumatic drugs in the spectrophotometric and colorimetric assays of serum enzymes was examined. None of the investigated methods was significantly influenced by caffeine, phenacetin, ibuprofen or indomethacin. Acetylsalicylic acid affected the continuous assays of creatine kinase and lactate dehydrogenase (with pyruvate as substrate), and the colorimetric assay of alanine aminotransferase. Aminophenazone interfered with the colorimetric method for determination of aspartate aminotransferase and alanine aminotransferase, while phenobarbital interfered only with the continuous method for lactate dehydrogenase (with L-lactate as substrate). Ketoprofen interfered with the colorimetric assays of lactate dehydrogenase and aspartate aminotransferase, while diclofenac affected the continuous assay of aspartate aminotransferase. None of the tested drugs interfered with the continuous methods for the determination of alkaline phosphatase and alpha-hydroxybutyrate dehydrogenase.

Human red cell adenylate kinase polymorphism in Srbija, Yugoslavia.

Red cell adenylate kinase (AK) phenotypes were determined in 283 unrelated adults in Srbija (Yugoslavia). The gene frequencies observed were: AK1 0.961 and AK2 0.039. The adenylate kinase activity was estimated in all haemolysates; no significant differences were found between individuals of different phenotypes.