Self-assembled growth of Au islands on a Mo(110) surface.

The self-assembled growth of epitaxial Au(111) islands on a Mo(110) buffer layer has been investigated as a function of growth temperature and amount of deposited material by reflection high energy electron diffraction and atomic force microscopy. At the growth temperature of 385 degrees C the dendrite-shaped islands coexist with the compact ones. The uniform islands formed at 500 degrees C adopt mostly a shape of truncated pyramids with a well developed (111) top plane and {111} and {100} side facets. As the growth temperature reaches 800 degrees C the Au islands take less regular shapes due to occurrence of coalescence. The averaged area and height of the islands increase with the deposition temperature and the amount of deposited material. The surface density of the islands decreases with increasing temperature. The epitaxial relations at the interface between the Au islands and the Mo buffer determined from the angular dependence of the electron diffraction pattern favour the Nishiyama-Wassermann growth mode. Factors responsible for the island-like growth and possible mechanisms of diffusion are discussed in details.

On defects' role in enhanced perpendicular magnetic anisotropy in Pt/Co/Pt, induced by ion irradiation.

Modifications of magnetic and magneto-optical properties of Pt/Co(d Co )/Pt upon Ar+ irradiation (with energy 1.2, 5 and 30 keV) and fluence, F at the range from 2 · 1013-2 · 1016 Ar+ cm-2) were studied. Two 'branches' of increased perpendicular magnetic anisotropy (PMA) and enhanced magneto-optical response are found on 2D (d Co , F) diagrams. The difference in F between 'branches' is driven by ion energy. Structural features correlated with magnetic properties have been analysed thoroughly by x-ray diffraction, Rutherford backscattering spectrometry and positron annihilation spectroscopy. Experimental results are in agreement with TRIDYN numerical calculations of irradiation-induced layers intermixing. Our work discusses particularly structural factors related to crystal lattice defects and strain, created and modified by irradiation, co-responsible for the increase in the PMA.

Features of motor control in patients with proximal childhood spinal muscle atrophy (pilot study).

The differences in the motor performance during different tasks between 19 subjects suffering from SMA and 10 healthy controls were observed. The simultaneous EMG activity of twelve lower limbs and lower trunk muscles was recorded with surface electrodes. EMG data were automatically reduced and compared with data evaluated from performed by physiotherapist manual testing of muscle strength. Results showed characteristic differences between healthy and spinal muscular atrophy (SMA) subjects: 1. SMA patients display generally more activity occurring in numerous muscle groups and more spinal levels are activated. 2. SMA patients reveal a disturbed functional relation between the posterior and anterior compartments of muscles. 3. EMG activity in SMA patients is spreading out also to the contralateral muscle groups even during slight, unilateral singlejoint movements. Oligosegmental, plurisegmental and brain sources are probably responsible for mentioned phenomena. The reciprocal influences between reduced number of motoneurons (in SMA) and function of central movement generators results in different mode of movement execution in SMA patients.

Motor unit changes in inflammatory myopathy and progressive muscular dystrophy.

The aim of present study was to analyse the motor unit (MU) changes in progressive muscle dystrophy (PMD) and in inflammatory myopathy (IM) and to evaluate eventual neurogenic factors in MU reorganisation. The material consisted of 20 patients with (PMD), 20 patients with (IM) and 20 healthy age-matched volunteers. The shape of concentric needle motor unit potentials (cn MUPs), including their duration, amplitude, area, size index and number of phases, the interference pattern and the amplitude and area of macro MUPs were evaluated. The cn emg data satisfied the classical criteria for myopathy in all examined patients, at least in one of the tested muscles. A decreased amplitude and/or area of macro MUPs, compatible with myopathy, were observed in 32 of the 40 patients. In some cases of chronic IM and PDM the long duration polyphasic potentials were recorded. The size index (SI) value of long polyphasic MUPs was usually decreased or normal. This feature indicated that desynchronisation of "myopathic" MUPs results from a reduced number of muscle fibers and their degeneration and regeneration. The results indicated no difference in MU reorganization between PMD and IM and no evidence of neurogenic factors in MU changes.

[Macro EMG in neuromuscular diseases]. / Zastosowanie metody makro-emg w diagnostyce chorób nerwowo-miesniowych.

The aim of this study is the introducing of macro-emg method as electrophysiological test used in diagnosis of neuromuscular diseases. The macro motor unit potentials (macro MUPs) obtained by recording macroelectrode (modified single-fibre electrode) represents temporal and spatial summation of individual single fiber action potentials belonging to whole motor unit territory--so the uptake area is larger for macroelectrode than for the concentric electrode, commonly used in emg routine work, when central main complex is generated only from less than 15 muscle fibers [10, 12, 13]. Additional information obtained by macro-emg method is spatial organisation of muscle fibers within the motor unit, so-called fiber density (F.D) In our study macro-emg examinations were performed in 20 healthy subjects, aged 21-55, without signs and symptoms of neuromuscular disorders. Macro MUPs were recorded using special programme for macro-emg and performed on electromyograph Counterpoint. 37 muscles (20 BB and 17 RF) were examined, and median values of amplitude, area of macro MUPs and F.D. in healthy subjects of different age were analyzed. Mean values of median for amplitude and area of macro MUPs in BB and RF muscles show respectively--148 microV, 382 microV x ms, and 319 microV, 763 microV x ms. Parameters of macro MUPs obtained in healthy subjects were compared to results obtained in 10 patients with myopathy and lower motor neuron lesion. Our results have confirmed the value of macro-emg method for investigating of the pathophysiological changes in motor units in neurogenic disorders, in myopathy the study should be continued.

[Urolithiasis and urinary tract abnormalities in children: own experience]. / Kamica moczowa u dzieci a wady ukladu moczowego w obserwacji wlasnej.

The study aimed analyzing case histories of 36 children (21 girls and 15 boys), from between 3 weeks and 17 years old, with urinary tract abnormalities, admitted to the Pediatric Nephrology Department for renal stone disease within a 5-year period (1995-1999). Most common clinical manifestations, requiring further urinary tract investigation, were: pain, urinary tract infections caused mainly by Gram-negative bacteria, and erythrocyturia. Most frequent anomalies observed in our patients were those resulting in urinary outlet obstruction. Disturbances in uremic acid and oxalate metabolism were abnormalities we have often found in the examined children. The majority of patients underwent a successful conservative treatment. The obtained results indicate that disorders in the urine flow are main risk factors for crystallization in children with urinary tract abnormalities.

[Polycystic renal disease in infants]. / Torbielowatosc nerek u niemowlat.

In the light of the observation of 4 infants with polycystic renal disease the clinical manifestation, diagnosis (with stress laid on USG) and therapeutic management are discussed. Attention is called to the possibility of adult-type polycystic renal disease in neonatal period and infancy. This type of nephropathy is supposed by the authors to be in 2 living children.

[Acute renal failure in neonates and infants]. / Ostra niewydolnosc nerek u noworodków i niemowlat.

Causes, course and prognosis in 90 cases of the acute renal failure in neonates and infants have been discussed. All cases were treated between 1971 and 1985. Recently, an increase in the incidence of the acute renal failure is being noted. The acute diarrhoea and hemolytico-uremic syndromes are the most frequent cause of the acute renal failure. Consequences of the acute renal failure and its complications require further nephrological care.

The solid state reaction of Fe with the Si(111) vicinal surface: splitting of bunched steps.

The solid state reaction of deposited Fe (four monolayers, ML) with vicinal Si(111) substrate induced by subsequent thermal treatment has been studied using scanning tunnelling microscopy. At the lower range of annealing temperatures up to 400 °C the bunched steps of bare substrate are reproduced by the surface of the covering iron silicide layer. At 400 °C the onset of three-dimensional growth of iron silicide islands is observed. In comparison to the samples covered with smaller amounts of Fe it appears at a lower annealing temperature. Above 500 °C the bunched steps split into lower ones but more densely distributed due to proceeding reactions between Fe-rich iron silicide and Si substrate. As a consequence, at 700 °C the well-developed three-dimensional nanocrystallites of iron silicide are randomly distributed on the Si surface. This observation is in contrast to the formation of a regular array of iron silicide crystallites upon deposition of 2 ML of Fe.

New possibilities for tuning ultrathin cobalt film magnetic properties by a noble metal overlayer.

Complementary multiscale magneto-optical studies based on the polar Kerr effect are carried out on an ultrathin cobalt wedge covered with a silver wedge and subsequently with the Au thick layer. A few monolayers of Ag are found to have a substantial effect on magnetic anisotropy, the coercivity field, and Kerr rotation. The silver overlayer thickness-driven magnetic reorientation from easy axis to easy plane generates a new type of 90 degrees magnetic wall for cobalt thicknesses between 1.3 and 1.8 nm. The tuning of the wall width in a wide range is possible. Tailoring of the overlayer structure can be used for ultrathin film magnetic patterning.

Modification of motor control of wrist extension by mesh-glove electrical afferent stimulation in stroke patients.

OBJECTIVE: To study the effect of mesh-glove afferent stimulation on motor control of voluntary wrist movement in stroke patients who have chronic neurological deficits. DESIGN: Case series. Motor control was evaluated by surface EMG of the arm muscles and kinematics of voluntary wrist movements on 3 occasions: before and immediately after the initial session of mesh-glove stimulation, and then after a daily mesh-glove stimulation program conducted over several months. SETTING: Tertiary care center. PATIENTS: The inclusion criteria were: a history of stroke lasting longer than 6 months; completion of a rehabilitation program during early recovery; and preserved cognitive and communicative ability. Fourteen referred patients (age 63 +/- 9yr; time since stroke 31 +/- 22mo) fulfilled the criteria and completed the daily stimulation program. INTERVENTION: A single initial and then daily mesh-glove electrical afferent stimulation was applied to the hand of the involved upper limb for 20 to 30min. MAIN OUTCOME MEASURES: Surface EMGs from the affected biceps brachii and wrist extensor muscles and amplitudes of wrist movements were analyzed. RESULTS: The single, initial mesh-glove application had no effect on outcome measures. Following a daily mesh-glove stimulation program, however, both the amplitude of wrist extension movement and wrist extensor integrated EMG were significantly increased while coactivation of biceps brachii decreased. These findings were most prominent in subjects with partially preserved voluntary wrist movements. CONCLUSION: We conclude that daily mesh-glove stimulation can modify altered motor control and improve voluntary wrist extension movement in stroke subjects with chronic neurological deficits.