We report on angle-resolved photoelectron spectroscopy results of thin dysprosium-silicide layers formed on Si(1
1
1), taken with a toroidal analyzer allowing to image the energy surfaces in
k
||
...-space. At monolayer dysprosium coverages, where hexagonal DySi
2 grows with a
1
×
1
superstructure, electron pockets are observed at the
M
¯
points with highly anisotropic effective masses, and around a hole pocket at the
Γ
¯
point also an anisotropic dispersion is found. The band filling of these two bands amounts to one, indicating an even number of electrons assigned to the surface unit cell. Similar features are found for multilayer coverages, where hexagonal Dy
3Si
5 layers are formed with a
3
×
3
R
30
°
superstructure. Here, the influence of zone folding effects due to the
3
×
3
R
30
°
reconstructed layers in the bulk silicide is only weak because of the high surface sensitivity of the experiments.
Endocardial pacing system implantation has been performed in 15 children of mean age 37 months (ranging from 1 day to 89 months), Endocardial lead fixation was performed by means of slowly resorbable ...suture (Dexon) to allow spontaneous lead migration as the child grows. During a mean follow‐up period of 61 months (range 17–108 months), none of the patients needed reintervention for correcting the lead length to allow growth.
The effect of right ventricular pacing on left ventricular relaxation was studied in 13 patients (age 62 +/- 3 years), with the atrial sensing ventricular pacing mode (VDD). A control group of ...similar age (64 +/- 4 years) consisted of 11 patients with atrial pacing (AAI). The timing of events was determined in both groups at similar R-R intervals (921 +/- 77 ms vs 967 +/- 37 ms). The loading conditions as estimated by peak systolic wall stress (afterload) and end-diastolic left ventricular dimensions (preload) were approximately the same in both groups. The ratio of late to early filling velocities were similar in both groups. Dominant changes were: increased preejection period (142 +/- 13 ms vs 95 +/- 15 ms); and higher velocities of isovolumic relaxation flow (60 +/- 34 cm/s vs 25 +/- 4 cm/s) in patients with ventricular pacing. The isovolumic relaxation time was longer in patients with VDD pacing (127 +/- 14 ms vs 108 +/- 12 ms). Anterior systolic interventricular septal motion (paradoxal motion) was recorded in nine patients with VDD pacing and in none of the patients with AAI pacing. Isovolumic relaxation flow was detected during atrial pacing in five (45%) patients and in 13 (100%) patients during atrial sensing ventricular pacing, indicating asynchronous left ventricular relaxation. This data shows that VDD pacing compared to atrial pacing resulted in an altered activation pattern of the left ventricle, associated with delayed onset, asynchronous contraction with interventricular septal motion abnormalities and prolonged asynchronous left ventricular relaxation with abnormal motion manifested by the presence of isovolumic relaxation flow.
In patients in whom syncopal episodes are mainly caused by occasional drops in heart rate, Sudden Rate Drop intervention feature intends to provide high rate intervention pacing. New Vitatron Medical ...B.V. pacemaker system Clarity DDDR, provides AN option FOR recognizing Sudden Rate Drop and responding by intervention pacing until it detects the recovering.
In patients with carotid sinus syndrome it is possible to provoke this situation BY sinus carotidus massage. We have implanted 10 of these devices in our center, 2 of which in patients with hypersensitive carotid sinus syndrome. In both patients, we activated sudden rate drop intervention on DDD mode pacing and applied protocol for testing the necessary level of Sudden Rate Drop Intervention Rate. Both patients gave their informed consent to be submitted to this testing. Pacemaker software assumes rate intervention level of 110 bpm. We tested our patients for rate levels of 90 and 110 bpm. Massaging the carotid sinus during 5 seconds, we provoked Sudden Rate Drop Intervention 10 times, in each patient, 5 times at intervention rate of 90 and 5 times at 110 bpm. Patients were unaware of the programmed intervention rate and were merely expected to report any different sensations experienced during the testing.
In all 20 tests, pacemaker responded to sudden rate drop elicited by carotid sinus massage (100%), which was verified by selected event recordings. After the massage, neither of the patients registered any sensations at sudden rate drop intervention rate level of 90 bpm in a total od 10 tests (100%), while 8 out of 10 massages at 110 bpm intervention rate provoked palpitations (80%). On the grounds of this testing, we concluded that lowering of Sudden Rate Drop Intervention Rate Level from 110 BPM to 90 BPM does not affect the reliability of system reaction, but changes patient's awareness of heart beats.
As a final conclusion, it should be said that basic prerogatives of a pacing system: safety and efficacy with minimal energy consumption, and in this case, quality of life option that a patients practically does not feel intervention when it occurs, are all met.
Circulating tumor cells (CTCs) are present at low concentrations in the peripheral blood of patients with solid tumors. It has been proposed that the isolation, ex vivo culture, and characterization ...of CTCs may provide an opportunity to noninvasively monitor the changing patterns of drug susceptibility in individual patients as their tumors acquire new mutations. In a proof-of-concept study, we established CTC cultures from six patients with estrogen receptor-positive breast cancer. Three of five CTC lines tested were tumorigenic in mice. Genome sequencing of the CTC lines revealed preexisting mutations in the PIK3CA gene and newly acquired mutations in the estrogen receptor gene (ESR1), PIK3CA gene, and fibroblast growth factor receptor gene (FGFR2), among others. Drug sensitivity testing of CTC lines with multiple mutations revealed potential new therapeutic targets. With optimization of CTC culture conditions, this strategy may help identify the best therapies for individual cancer patients over the course of their disease.
The kinetics of the formation of the intermetallic CuTi
2 phase during isothermal annealing of thin-film Cu/Ti systems with an excess of Ti has been investigated. The thin-film Cu/Ti systems were ...deposited by magnetron sputtering of Cu and Ti in Ar at a gas pressure of 5 × 10
−2 Pa on two types of substrate at room temperature. The quantity of the phases formed after each annealing was determined by a quantitative X-ray analysis and an electrochemical anode dissolving method. It is shown that the formation of the intermetallic phase is limited by diffusion processes. On the basis of the Arrhenius' equation the activation energy and preexponential coefficient were determined.
Aorto-caval fistulas Davidovic, L B; Kostic, D M; Cvetkovic, S D ...
Cardiovascular surgery (London, England),
12/2002, Letnik:
10, Številka:
6
Journal Article
The surgical repair of 16 aorto-caval (A-C) fistulas (15 male and one female patient; average age of 61.3 years) is reviewed. Fourteen fistulas were caused by aneurysm's erosion, one by iatrogenic ...injury, while one followed abdominal blunt trauma. The interval from presumed occurrence to diagnosis ranged from 6 h to 2 years. The presence of an abdominal bruit (87.5%) was the most reliable physical finding. Congestive heart failure was prominent in three (18.7%) cases, while severe lower extremity edema in five (31.2%). Two patients (12.5%) had hematuria, two (12.5%) renal insufficiency, while four (25%) scrotal edema. The diagnosis was not recognized before the surgery in five (31.2%) cases. In all 16 cases after transaortic suture of the fistula, aortic reconstructions were performed. Four operative deaths (25%) occurred, in patients who were not correctly diagnosed before surgery. In one case the cause of death was massive bleeding, and in three MOFS. All other patients were followed from 1 to 17 years (mean 4 years and 2 months). All grafts are patent, and there is no lower extremity venous insufficiency or pelvic venous hypertension. Surgical repair of A-C fistulas is mandatory to prevent serious complications.
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