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11.
A Laurila A Bloigu S N?yh? J Hassi M Leinonen P Saikku 《Canadian Metallurgical Quarterly》1997,56(3):70-75
The Sámi people in northernmost Finland have lower mortality from cardiovascular diseases than the main population of Finland. Chronic infections caused by Chlamydia pneumoniae and Helicobacter pylori, both quite recently discovered gram-negative bacteria, have been associated with atherosclerosis. We studied the prevalence of these infections in Sámi and Finnish men by analysing the C. pneumoniae and H. pylori specific serum IgG and IgA antibodies using microimmune fluorescence and enzyme linked immunosorbent assay methods, respectively. The frequency of C. pneumoniae IgG antibodies and the age adjusted geometric mean titres differed significantly between these groups. The Finns were more often sero-positive than the Sámi (76% vs. 67%, respectively), the age adjusted geometric mean titre being 71.6 in the Finns and 38.3 in the Sámi; p = 0.001. No significant difference was found in the H. pylori IgG and IgA antibody prevalences, nor in the geometric mean titres between these groups. The difference in cardiovascular mortality between the Sámi and Finns may be partly explained by the lower incidence of chlamydial infections in the Sámi. 相似文献
12.
In this paper, the optimal process parameters of a wave soldering process were defined. The optimization was performed in respect to soldering quality by minimizing a cost function describing the total repairing cost of a wave-soldered printed circuit board (PCB). The data analysis stages were as follows. First, the process data were coded into inputs for a self-organizing map (SOM). Next, a function for the repairing cost was constructed and used to find the optimal map neurons. At the last phase, the optimal parameters were approximated on the basis of the reference vectors of the optimal neurons. The results showed clearly potential in the optimization of the wave soldering process, especially in the visualization of the optimal process conditions. Therefore, it would be useful to exploit the method more widely in the electronics industry. 相似文献
13.
14.
Liukkonen M. Hiltunen T. Havia E. Leinonen H. Hiltunen Y. 《Electronics Packaging Manufacturing, IEEE Transactions on》2009,32(2):89-96
Multilayer perceptrons (MLPs ) are well-known artificial neural networks (ANNs) that are used in many different applications. In this paper, MLP neural networks were used to predict product quality in a wave soldering research case. The aims were to construct process models and to determine whether the formation of soldering defects could be predicted reliably by using the method. In addition, the scope of the research included demonstrating the prediction performance of the created models. A MLP-based variable selection procedure with a back-propagation algorithm was used to create defect formation models and to find the most important factors affecting the number of detected defects. The process parameters were used as inputs for the MLP network and each defect type in turn as a model output. In conclusion, the results were promising, and the method used showed potential considering the wider use of the data processing procedure in the electronics or any other industry. 相似文献
15.
Petra S.Pálvölgyi Daniel Sebők Imre Szenti Eva Bozo Henri Ervasti Olli Pitkänen Jari Hannu Heli Jantunen Marko E.Leinonen Sami Myllymäki Akos Kukovecz Krisztian Kordas 《Nano Research》2021,14(5):1450-1456
In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm3), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10?4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band. 相似文献
16.
Leinonen Jenni A.; Solantaus Tytti S.; Punam?ki Raija-Leena 《Canadian Metallurgical Quarterly》2003,17(3):409
This study focused on how factors outside the home affect the quality of mothering and fathering. Economic pressure and workload were evaluated along with the compensating role of social support on parenting. Information was gathered from 842 mothers and 573 fathers including 139 single-mother and 21 single-father families. The results showed that the nature of the strains, together with parental gender and family structure, influenced their effects on parenting. The results further revealed some gender- and strain-specific protective functions of social support on parenting. For example, economic pressure was related to increased punitive parenting, which was compensated by instrumental and emotional support among the mothers. Workload was related to less authoritative single fathering, which was compensated by instrumental support. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
Lipovskii AA Kuittinen M Karvinen P Leinonen K Melehin VG Zhurikhina VV Svirko YP 《Nanotechnology》2008,19(41):415304
We demonstrate that the dissolution of 10?nm metal nanoparticles localized in the subsurface layer of silicate glass by static electric field can be employed to alter the optical density and surface profile of the glass-metal composite with spatial resolution of 200?nm. The developed technique, which can be referred to as electric field imprinting (EFI), offers an attractive alternative to conventional micro-?and nano-pattering techniques. 相似文献
18.
P Toikka S Nikkari O Ruuskanen M Leinonen J Mertsola 《Canadian Metallurgical Quarterly》1999,37(3):633-637
Blood-based pneumolysin PCR was compared to blood culture and detection of pneumolysin immune complexes, as well as to detection of antibodies to pneumolysin and to C polysaccharide, in the diagnosis of pneumococcal infection in 75 febrile children. Invasive pneumococcal infection was suspected on clinical grounds in 67 of the febrile children, and viral infection was suspected on clinical grounds in 8 of the febrile children. In addition, 15 healthy persons were examined to test the specificity of the PCR assay. Plasma, serum, and leukocyte fractions were analyzed by PCR. The combination of all test results led to the diagnosis of pneumococcal infection in 25 patients. Pneumolysin PCR was positive in 44% of these children, an increase occurred in the pneumolysin antibodies in 39% and in the C polysaccharide antibodies in 30% of the patients; pneumolysin immune complexes were found in convalescent serum in 30%, pneumolysin immune complexes occurred in acute-phase serum samples in 16%, and a positive blood culture was found in 20% of the patients. None of the healthy controls had positive results by PCR. The results suggest that the diagnosis of Streptococcus pneumoniae infection from blood samples necessitates the use of several different assays. Pneumolysin PCR was the most sensitive assay, but its clinical value is reduced by the fact that three blood fractions are needed. 相似文献
19.
T Sorsa T Salo E Koivunen J Tyynel? YT Konttinen U Bergmann A Tuuttila E Niemi O Teronen P Heikkil? H Tschesche J Leinonen S Osman UH Stenman 《Canadian Metallurgical Quarterly》1997,272(34):21067-21074
Increased production of proteinases, such as matrix metalloproteinases (MMPs), is a characteristic feature of malignant tumors. Some human cancers and cell lines derived from them also express trypsinogen, but the function of the extrapancreatic trypsin has remained unclear. In this study we cloned and sequenced trypsinogen-2 cDNA from human COLO 205 colon carcinoma cells and characterized the ability of the enzyme to activate latent human type IV procollagenases (proMMP-2 and proMMP-9). As shown by cloning and N-terminal amino acid sequencing, the amino acid sequence of tumor-associated trypsin-2 is identical to that of pancreatic trypsin-2. We found that both pancreatic trypsin-2 and tumor cell-derived trypsin-2 are efficient activators of proMMP-9 and are capable of activating proMMP-9 at a molar ratio of 1:1000, the lowest reported so far. Human trypsin-2 was a more efficient activator than widely used bovine trypsin and converted the 92-kDa proMMP-9 to a single 77-kDa product that was not fragmented further. The single peptide bond cleaved by trypsin-2 in proMMP-9 was Arg87-Phe88. The generation of the 77-kDa species coincided with the increase in specific activity of MMP-9. In contrast, trypsin-2 only partially activated proMMP-2. Trypsin-2 cleaved the Arg99-Lys100 peptide bond of proMMP-2 generating 62-65-kDa MMP-2 species. Trypsin-2-induced proMMP-2 and -9 conversions were inhibited by tumor-associated trypsin inhibitor added either prior to or during activation indicating that proMMPs were not activated autocatalytically. Trypsin-2 also activated proMMPs associated with tissue inhibitor of matrix metalloproteinases, the complexes of which are thought to be the major MMP forms in vivo. The ability of human tumor cell-derived trypsin-2 to activate latent MMPs suggests a role for trypsin-2 in initiating the proteinase cascade that mediates tumor invasion and metastasis formation. 相似文献
20.
Stress corrosion cracking (SCC) susceptibility of austenitic EN1.4301 (AISI 304) and EN1.4404 (AISI 316L) stainless steels
was studied using the constant load method and polymer (PTFE) crevice former in order to study the effects of crevice on SCC
susceptibility. The uniaxial active loading tests were performed in 50 pct CaCl2 at 373 K (100 °C) and in 0.1 M NaCl at 353 K
(80 °C) under open-circuit corrosion potential (OCP) and electrochemical polarization. Pitting, crevice, and SCC corrosion
were characterized and identified by acoustic emission (AE) analysis using ∆t filtering and the linear locationing technique. The correlation of AE parameters including amplitude, duration, rise time,
counts, and energy were used to identify the different types of corrosion. The stages of crevice corrosion and SCC induced
by constant active load/crevice former were monitored by AE. In the early phase of the tests, some low amplitude AE activity
was detected. In the steady-state phase, the AE activity was low, and toward the end of the test, it increased with the increasing
amplitude of the impulses. AE allowed a good correlation between AE signals and corrosion damage. Although crevice corrosion
and SCC induced AE signals overlapped slightly, a good correlation between them and microscopical characterization and stress-strain
data was found. Especially, the activity of AE signals increased in the early and final stages of the SCC experiment under
constant active load conditions corresponding to the changes in the measured steady-state creep strain rate of the specimen.
The results of the constant active load/crevice former test indicate that a crevice can initiate SCC even in the mild chloride
solution at low temperatures. Based on the mechanistic model of SCC, the rate determining step in SCC is thought to be the
generation of vacancies by selective dissolution, which is supported by the low activity phase of AE during the steady-state
creep strain rate region. 相似文献