Janne J. Jokinen

Atomic Layer Epitaxy Growth of TiN Thin Films from Til4 and NH 3

TiN thin films were grown by atomic layer epitaxy using titanium tetraiodide (TiI 4 ) and ammonia (NH 3 ) as precursors. The films were characterized with Rutherford backscattering spectrometry, time-of-flight elastic recoil detection analysis, energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and resistivity measurements. Both the growth rate and film quality were markedly dependent on the growth temperature. As the temperature was increased from 400 to 500°C the growth rate increased from 0.12 to 0.30 A/cycle, and the resistivity decreased from 380 to 70 μΩ cm. Also, the oxygen content decreased with increasing temperature being about 10 atom % in the films grown at 475 to 500°C. The iodine contents were below 0.5 atom %.

Atomic layer epitaxy growth of aluminum oxide thin films from a novel Al(CH3)2Cl precursor and H2O

The deposition of Al2O3 thin films by atomic layer epitaxy was investigated using Al(CH3)2Cl as a new aluminum precursor. All the films grown in the temperature range of 125–500 °C were amorphous as examined by x-ray diffraction analysis. The residual contents of carbon, chlorine, and hydrogen in the film deposited at 200 °C were 0.2, 2.1, and 12 at. %, respectively, and diminished rapidly with increasing growth temperature. The refractive index of the films increased with deposition temperature, stabilizing at the highest value of 1.68 above 300 °C. The permittivity of the films increased from 7.3 to 8.7 with increasing growth temperature from 200 to 500 °C. The leakage current density was lowest in the film deposited at 200 °C and increased markedly at higher deposition temperatures.

Effects of intermediate zinc pulses on properties of TiN and NbN films deposited by atomic layer epitaxy

The reasons for the improvements gained by using intermediate zinc pulses in atomic layer epitaxy growth of TiN and NbN films were examined by a comprehensive characterization and comparison of films prepared from TiCl4 or NbCl5 and NH3 with and without zinc. The characterization techniques used comprise time-of-flight elastic recoil detection analysis, secondary ion mass spectrometry, Rutherford backscattering spectrometry, nuclear resonance broadening, proton backscattering spectrometry, deuteron induced reactions, proton induced X-ray emission, atomic force microscopy, scanning electron microscopy, X-ray diffraction, and Hall effect and reflectance measurements. The effect of zinc was found to be manifold: both compositional and structural changes were observed. In the case of TiN the major improvement gained by using zinc was significantly decreased oxygen contamination whereas a marked increase of grain size was the dominant effect observed with NbN. A clear correlation between the compositional and structural changes and the improvements of the electrical properties was established.

Analysis of AlN thin films by combining TOF-ERDA and NRB techniques

Light atom impurities in polycrystalline AlN thin films deposited by atomic layer epitaxy on glass substrates have been analysed by combining two high-energy ion beam techniques, namely time-of-flight elastic recoil detection analysis and nuclear resonance broadening techniques. The advantages of their combined use in depth profiling of light elements, H, C, O and Cl impurity traces in the present study, are demonstrated in the framework of optimizing the production of pure A1N thin films from AlCl3 and Al(CH3)3 aluminium sources.

Health-related quality of life after coronary artery bypass grafting: a review of randomized controlled trials.

Abstract  Objective outcome measures (i.e., survival, mortality, morbidity, complication rate, symptom recurrence, and need for re‐interventions) have long been used as benchmarks for successful cardiac surgery, including coronary artery bypass grafting (CABG). Along with these objectively measurable outcome indicators, acquired improvement by cardiac surgery in subjectively experienced health‐related quality of life (HRQoL) has gained importance during the last decade in cardiac surgical research. If an increasing proportion of adult patients referred for CABG are elderly, octogenarians or even nonagenarians, the acquired HRQoL benefit from bypass surgery should be considered to be at least as important an outcome measure as potentially marginal improvement in life expectancy or longevity alone. To achieve the maximal HRQoL benefit and to optimize patient selection, a comprehensive analysis and understanding of contributors that affect pre‐ and postoperative self‐perceived HRQoL is essential. These include patient‐related characteristics (e.g., demographics and underlying comorbidities), surgical technique‐related factors, and healthcare‐related attributes. In this paper we review the randomized controlled trials published during the last ten years to analyze the effect of CABG on HRQoL. Specifically, we focus on the differences between the on‐pump and off‐pump (OPCAB) bypass techniques, investigate the factors that contribute to post‐CABG HRQoL, and study post‐CABG HRQoL in elderly patients. (J Card Surg 2010;25:309‐317)

Pacemaker Therapy After Tricuspid Valve Operations: Implications on Mortality, Morbidity, and Quality of Life

BACKGROUND We studied the incidence and predictors of permanent pacemaker implantation after tricuspid valve operation and its implications on patient outcome in terms of survival, morbidity, and quality of life. METHODS Between 1992 and 2007, 136 consecutive patients underwent tricuspid valve repair or valve replacement with a biologic valve at Kuopio University Hospital. Comprehensive clinical data were recorded prospectively. Data for the Nottingham Health Profile quality of life analysis were collected cross-sectionally. RESULTS The mean follow-up time was 7.9 +/- 4.1 years (range, 0.8 to 15.7 years). A pacemaker was implanted in 28 patients (21%); 54% were implanted before hospital discharge. The 10-year survival of patients with a pacemaker was higher (94%) than of patients without a pacemaker (59%; p = 0.050). The need of a pacemaker was related to a significantly higher rate of transient ischemic attacks (30% vs 6%, p = 0.004), strokes (9% vs 4%; p = 0.008), and impaired physical capacity in terms of higher New York Heart Association functional class (p = 0.03) and the quality of life scores describing energy (31 vs 17; p = 0.01) and mobility (32 vs 17; p = 0.005). CONCLUSIONS The need for pacemaker implantation after tricuspid valve operations was high. Unexpectedly, the life expectancy of the patients who needed a pacemaker postoperatively was higher compared with those who did not. This beneficial effect on mortality was offset by impaired morbidity: patients with a pacemaker experienced a significantly higher rate of thromboembolic complications and impaired quality of life.

Clinical value of intra-operative transit-time flow measurement for coronary artery bypass grafting: a prospective angiography-controlled study

OBJECTIVE Transit-time flow measurement (TTFM) is the most widely used method for intra-operative graft quality control in coronary artery bypass surgery. Although it may provide the opportunity for the surgeon to promptly revise the graft before the patient is discharged from the operating room, controlled clinical data on the ultimate usefulness of the TTFM are scarce. Clear cut-off values for when to revise grafts have not been set. METHODS A total of 204 consecutive grafts (left internal mammary artery (n=46), vein graft (n=155), and radial artery (n=3)) underwent TTFM in 75 elective coronary artery bypass grafting (CABG) patients. The following parameters were recorded: mean graft flow (MGF), pulsatility index (PI), and insufficiency ratio (IR). After a mean follow-up of 199 ± 42 days, coronary angiography was performed for assessment of graft patency. RESULTS A total of 166 grafts were found to be patent (85%), and 29 (15%) were completely occluded. The median and interquartile range (IQR) of MGF for the occluded grafts at the time of surgery was 38 ml min(-1) (IQR, 2549 ml min(-1)) and for the patent grafts 45 ml min(-1) (IQR, 31-71 ml min(-1); p=ns]. The corresponding PI values were 3.3 (IQR, 2.8-5.0) and 2.2 (IQR, 1.7-3.2; p=0.003), and the IR values were 1.6 (IQR, 0.6-6.1) and 0.2 (IQR, 0-2.2; p=0.03). By receiver operating characteristic (ROC) analysis, the highest sensitivity (72%) and specificity (70%) were associated with a PI value>3.0. However, 49 out of 70 such grafts (70%) were found to be patent. Furthermore, 10 out of 16 (63%) grafts, that had a combination of low flow (MGF<15 ml min(-1)) and high PI (>3.0), were patent at control angiography. CONCLUSIONS TTFM predicts graft failure within the 6 months after CABG. However, specific cut-off recommendations for when to revise a graft cannot be set on the basis of TTFM. The cut-off values suggested in the literature lead to unnecessary graft revisions in the majority of cases, and, on the other hand, many technical defects probably remain unnoticed. Better methods to assess the quality of coronary artery bypass grafts are needed.

Critical Role of VEGF-C/VEGFR-3 Signaling in Innate and Adaptive Immune Responses in Experimental Obliterative Bronchiolitis

Chronic inflammation, a hallmark of obliterative bronchiolitis, is known to induce lymphangiogenesis. We therefore studied the role of lymphangiogenic vascular endothelial growth factor C (VEGF-C), its receptor VEGFR-3, and lymphangiogenesis during development of experimental obliterative bronchiolitis [ie, obliterative airway disease (OAD)] in rat tracheal allografts. The functional importance of VEGF-C was investigated by adenovirus-mediated overexpression of VEGF-C (AdVEGF-C), and by inhibition of VEGF-C activity with VEGFR-3-Ig (AdVEGFR-3-Ig). Analyses included histology, immunohistochemistry, and real-time RT-PCR 10 and 30 days after transplantation. In the course of OAD development, lymphangiogenesis was induced in the airway wall during the alloimmune response, which was reversed by cyclosporine A in a dose-dependent fashion. VEGF-C overexpression in tracheal allografts induced epithelial activation, neutrophil chemotaxis, and a shift toward a Th17 adaptive immune response, followed by enhanced lymphangiogenesis and the development of OAD. In contrast, inhibition of VEGF-C activity with VEGFR-3-Ig inhibited lymphangiogenesis and angiogenesis and reduced infiltration of CD4(+) T cells and the development of OAD. Lymphangiogenesis was linked to T-cell responses during the development of OAD, and VEGF-C/VEGFR-3 signaling modulated innate and adaptive immune responses in the development of OAD in rat tracheal allografts. Our results thus suggest VEGFR-3-signaling as a novel strategy to regulate T-cell responses in the development of obliterative bronchiolitis after lung transplantation.

Natural course and risk factors for impaired renal function during the first year after heart transplantation

BACKGROUND Post-operative renal failure is a common and potentially hazardous complication after heart transplantation (HTx). In this study we characterized pre- and post-operative risk factors for acute renal failure requiring renal replacement therapy (RRT). METHODS Ninety-three patients underwent orthotopic HTx between 2000 and 2007. The risk factors for RRT during the early post-operative period and predictors contributing to impaired renal function within the first post-transplant year were analyzed by regression analysis. The impact of pre-operative renal failure and early post-operative RRT on renal function within 1 year were studied. RESULTS Before HTx, 55% of patients (51 of 93) had normal renal function or mild renal failure (glomerular filtration rate [GFR] >60 ml/min/1.73 m(2)). Before discharge from the hospital, 25% (23 of 93) developed acute renal failure and required RRT. Of these, 16% (8 of 51) had pre-operatively normal renal function or mild renal failure, and 36% (15 of 42) had moderate or severe renal failure (GFR <60 ml/min/1.73 m(2); p = 0.02). The prognosticators for early RRT were prolonged graft dysfunction, re-admission to the operating room due to post-operative bleeding, poor diuresis during surgery (<1,000 ml), pre-operative pacemaker implantation, intubation time >24 hours, pre-operative GFR <60 ml/min/1.73 m(2), post-operative troponin T >6 microg/liter and pre-operative use of angiotensin receptor blocker. CONCLUSIONS Pre-operative renal failure is a significant risk factor for RRT during the immediate post-operative period and requires aggressive treatment. Patients with pre-operative renal failure secondary to severe heart failure and acute post-operative renal failure requiring RRT tend to recover within the first year post-HTx.

Beneficial effect of resin salve in treatment of severe pressure ulcers: a prospective, randomized and controlled multicentre trial

Background  Resin salve of the Norway spruce (Picea abies) has been used in folk medicine to heal wounds and infections.