Dynamic micro-Hall detection of superparamagnetic beads in a microfluidic channel

We report integration of an InAs quantum well micro-Hall magnetic sensor with microfluidics and real-time detection of moving superparamagnetic beads. Beads moving within and around the Hall cross area result in positive and negative Hall voltage signals respectively. Relative magnitudes and polarities of the signals measured for a random distribution of immobilized beads over the sensor are in good agreement with calculated values and explain consistently the shape of the dynamic signal.

Surface spin flip probability of mesoscopic Ag wires

Spin relaxation in mesoscopic Ag wires in the diffusive transport regime is studied via nonlocal spin valve and Hanle effect measurements performed on Permalloy/Ag lateral spin valves. The ratio between momentum and spin relaxation times is not constant at low temperatures. This can be explained with the Elliott-Yafet spin relaxation mechanism by considering the momentum surface relaxation time as being temperature dependent. We present a model to separately determine spin flip probabilities for phonon, impurity and surface scattering and find that the spin flip probability is highest for surface scattering.

Negative nonlocal resistance in mesoscopic gold Hall bars: absence of the giant spin Hall effect

We report the observation of negative nonlocal resistances in multiterminal mesoscopic gold Hall bar structures whose characteristic dimensions are larger than the electron mean-free path. Our results can only be partially explained by a classical diffusive model of the nonlocal transport, and are not consistent with a recently proposed model based on spin Hall effects. Instead, our analysis suggests that a quasiballistic transport mechanism is responsible for the observed negative nonlocal resistance. Based on the sensitivity of our measurements and the spin Hall effect model, we find an upper limit for the spin Hall angle in gold of 0.023 at 4.5 K.

A quantitative morphometric study of rectal mucosa in adult and aged healthy subjects

Rectal mucosa is relatively susceptible to pathological processes and frequently it is affected by various diseases. However, there is a notable lack of quantitative data regarding normal rectal mucosa, which would provide a reference for histoquantitative studies of the pathologically changed tissue. Therefore, we obtained the tissue from 27 healthy patients subjected to diagnostic rectoscopy during active screening for asymptomatic cancer of the large intestine, in which no disease was found. Using computer-aided morphometric analysis, we studied all structural elements of the rectal mucosa. The patients were divided into four groups according to the age and sex: adult males, elderly males, adult females and elderly females. The patients under 60 years of age were grouped as adult and those older than 60 years as aged subjects. A decreased height of surface epithelium was registered in both elderly male and female groups. This finding, however, was significant only when adult and elderly male groups were compared. The tendency towards reduction of the mucosal height was also registered comparing male adult and elderly groups. The number of crypts per 0.1 mm2 of tissue increased with aging in both males and females, whereby the crypts were always more numerous in males than in females. The increase in number of crypts in male subjects was accompanied by a decrease in their diameter and perimeter. The changes associated with ageing were discrete and affected only the male subjects.

[Recall of metamizole from the market in countries with modern pharmacotherapy]

Metamizole sodium (noraminophenazon sodium) is a pyrazolone derivate with analgesic, antipyretic and antiinflammatory activity, introduced in therapy in 1921. Since then, it was widely used all over the world, even in the counter preparations. In seventies its use was connected with severe, sometimes fatal side effects (agranulocytosis), resulting in gradual withdrawal of the drug. Metamizol has been withdrawn from the market in many developed countries, its use severely restricted in some of them, or permitted only in parenteral preparations for strictly defined indications (exceptionally severe pain such as posttraumatic, postoperative, abdominal colics and high body temperature unresponsive to the other antipyretics. In contrast to that, preparations containing metamizole are still in use in many countries, in some even as over the counter drugs.

[Mortality in malignant brain tumors in Yugoslavia]

Malignant tumours of head and neck, as a common group of diseases, is mentioned in Yugoslavia for the first time in 1972, where as the american authors have been studying this group of diseases as a whole since 1954 (1969). The data about death persons of malignant brain tumours (codes 191), of all causes of death (codes 000-999), of defined death causes of all the neoplasms (codes 140-209) and neoplasms of head and necks (codes 140-149, 160-161, 190-193), according to the eighth and ninth Revision of the International Classification of Diseases, Lesions and Death Causes, are based on official data of the Institute of Statistics of Yugoslavia for the period 1969-1988 (1988). In the analysis of mortality were used the standardized death rates according to the method of direct standardization after the world population by Segi (1976), further specific death rates according to sex and age, proportions and linear trend (1983). The results of these researches have shown that in the period from 1969 to 1988 there were recorded in Yugoslavia 13687 dead of malignant brain tumours in all. The average standardized mortality rate was 2.94 per 100,000 inhabitants; it is higher in men (3.59), than in women (2.40). On the basis of the results of linear trend it is shown that the average standardized rates of total mortality are increasing (y = 2.94 + 0.16x); it is in the males y = 3.59 + 0.23x, in females y = 2.40 + 0.12x. Age specific mortality rates are the highest in the group 55-64 years (10.37%). In this group the risk of dying is much greater in the males (13.63%), than in the females (7.85%).