Das Lebenswerk der Sibirienforscherin Zoja Sokolova in einem Band

Kirjallisuusarvostelu

Narrow-band 1, 2, 3, 4, 8, 16 and 24 cycles/360º angular frequency filters

We measured human frequency response functions for seven angular frequency filters whose test frequencies were centered at 1, 2, 3, 4, 8, 16 or 24 cycles/360º using a supra-threshold summation method. The seven functions of 17 experimental conditions each were measured nine times for five observers. For the arbitrarily selected filter phases, the maximum summation effect occurred at test frequency for filters at 1, 2, 3, 4 and 8 cycles/360º. For both 16 and 24 cycles/360º test frequencies, maximum summation occurred at the lower harmonics. These results allow us to conclude that there are narrow-band angular frequency filters operating somehow in the human visual system either through summation or inhibition of specific frequency ranges. Furthermore, as a general result, it appears that addition of higher angular frequencies to lower ones disturbs low angular frequency perception (i.e., 1, 2, 3 and 4 cycles/360º), whereas addition of lower harmonics to higher ones seems to improve detection of high angular frequency harmonics (i.e., 8, 16 and 24 cycles/360º). Finally, we discuss the possible involvement of coupled radial and angular frequency filters in face perception using an example where narrow-band low angular frequency filters could have a major role.

Molecular identification of Sicilian (dß)º-thalassemia associated with ß-thalassemia and hemoglobin S in Brazil

We describe the clinical and molecular characteristics of two unrelated Brazilian families with an association of the Sicilian form of (dß)º-thalassemia with hemoglobin S and ß-thalassemia. Direct sequencing of the ß-globin gene showed only the hemoglobin S mutation in patient 1 and the ß-thalassemia IVS1-110 in patient 2. The other allele was deleted in both patients and PCR of DNA samples of the breakpoint region of both patients showed a band of approximately 1,150 bp, expected to be observed in the DNA of carriers of Sicilian (dß)º-thalassemia. The nucleotide sequence of this fragment confirmed the Sicilian deletion. There are few reports concerning the Hb S/(dß)º-thalassemia association and patient 2 is the first reported case of Sicilian type of (dß)º-thalassemia in association with ß-thalassemia documented at the molecular level.

The calcium-dependent protease of Loxosceles gaucho venom acts preferentially upon red cell band 3 transmembrane protein

Eighty micrograms red blood cell (RBC) ghosts from patients who had previously exhibited the cutaneous form of loxoscelism (presenting localized dermonecrosis) and the viscerocutaneous form of loxoscelism (presenting dermonecrosis, hemoglobinuria, hematuria, and jaundice) and from controls were incubated with 2.5 µg crude Loxosceles gaucho venom in 5 mM phosphate buffer, pH 7.4, at 37ºC. Among all membrane proteins, quantitative proteolysis of the important integral transmembrane protein 3 increased with venom dose and with incubation time from 30 to 120 min, as demonstrated by gel densitometry. Similar quantitative data were obtained for RBC ghosts from patients and from control subjects, a fact that argues against the possibility of genetic factors favoring the hemolytic viscerocutaneous form. These data suggest that the clinical forms may be different types of the same disease, with the viscerocutaneous form being the result of large amounts of intravascularly injected venom and the superficial form being the result of in situ venom action. Since protein 3 is a housekeeping integral membrane protein, whose genetic deficiency leads to hemolytic anemia, it is reasonable to relate it to the hemolysis which occurs in the viscerocutaneous form of loxoscelism. The venom protease responsible for the process was not inhibited after 120-min incubation by 0.2 mM paramethylsulfonyl fluoride or by 0.2 mM N-ethylmaleimide but was inhibited by 25 mM ethylenediaminetetraacetic acid (a calcium-chelating agent) in 5 mM phosphate buffer at pH 7.4, which suggests that the enzyme is a calcium-dependent metalloprotease.

Behavioral characteristics of the offspring of adolescent rats

The aim of this study was to test the hypothesis that, during adulthood, the offspring of adolescent rats differ in emotionality, learning and memory from the offspring of adult rats. The behavior of the offspring of adolescent (age, 50-55 days) and adult rats (age, 90-95 days) was tested in the open field, activity cage, and passive and active avoidance apparatus. The latencies during training and testing in the passive avoidance apparatus of the offspring of adolescent parents were shorter than the latencies of control offspring (P<0.001 on both training and testing days). Offspring of adolescent parents showed shorter latency time in acquisition trials during active avoidance testing compared to control offspring (P<0.001). They also showed a higher number of active avoidance responses in the last four blocks of acquisition (P<0.001) and first two blocks of extinction trials (P<0.05 and P<0.001, respectively). The offspring of adolescent parents showed higher latency on the first day of testing in the open field (P<0.01) and a lower latency on the third day of testing (P<0.01). They also showed higher activity during all three days of testing (1st and 2nd day: P<0.01; 3rd day: P<0.05). The spontaneous activity of the offspring of adolescent parents in the activity cage was higher in the last three intervals of testing (P<0.001). In summary, the offspring of adolescent parents were less anxious and tended to be more active. The results of two learning and memory tests were opposite, but could be explained by a higher exploratory drive of the offspring of adolescent parents. This was probably due to chronic malnutrition stress and the disturbed mother-infant relationship in the litters of adolescent mothers.

Evaluation of two 99mTc-DTPA radioaerosols with different characteristics in lung ventilation studies

Two radioaerosol preparations, TechneScan®-DTPA (99mTc-DTPA, 40 mCi/3 ml; IPEN-CNEN, São Paulo, SP, Brazil) and TechneScan®-DTPA/AEROSOL (99mTc-DTPA/A, 15 mCi/1.5 ml with 0.5 ml ethanol; Mallinckrodt Medical, St. Louis, MO, USA), were compared in pulmonary ventilation studies in terms of total radiocounts and clearance after inhalation. An aerosol with ethanol is supposed to better distribute the radioparticles in the lungs. Twenty normal nonsmoking volunteers (10 men and 10 women), mean age of 23.2 years (range: 20 to 35 years), were studied. Images were obtained immediately and 30, 60 and 90 min after inhalation. Total and regional counts were obtained and the clearance half-lives of both lungs were determined. There was no difference in total counts between the two types of radioaerosol at any time (mean of ~188,000 cpm for male and female subjects at time zero in both aerosols). The highest count was obtained in the middle region of both lungs (P<0.001) with both preparations. The clearance half-life did not differ between aerosols (mean of ~80-88 min for male and female subjects for both aerosols). Small nonsignificant regional differences were observed. No differences between genders or between right and left lung were observed. 99mTc-DTPA/A generated the highest output of radioaerosol. 99mTc-DTPA with alcohol costs approximately five times more than the aerosol without alcohol. The present results show that either kind of aerosol may be adopted routinely for use in pulmonary examinations without affecting diagnosis. We suggest that the amount of 740 mBq (20 mCi) of 99mTc-DTPA in 1.5 ml saline can be used for routine examinations resulting in reduction of costs in pulmonary ventilation studies without diagnostic impairment.

Infrared coagulation versus rubber band ligation in early stage hemorrhoids

The ideal therapy for early stages of hemorrhoids is always debated. Some are more effective but are more painful, others are less painful but their efficacy is also lower. Thus, comfort or efficacy is a major concern. In the present randomized study, a comparison is made between infrared coagulation and rubber band ligation in terms of effectiveness and discomfort. One hundred patients with second degree bleeding piles were randomized prospectively to either rubber band ligation (N = 54) or infrared coagulation (N = 46). Parameters measured included postoperative discomfort and pain, time to return to work, relief in incidence of bleeding, and recurrence rate. The mean age was 38 years (range 19-68 years). The mean duration of disease was 17.5 months (range 12 to 34 months). The number of male patients was double that of females. Postoperative pain during the first week was more intense in the band ligation group (2-5 vs 0-3 on a visual analogue scale). Post-defecation pain was more intense with band ligation and so was rectal tenesmus (P = 0.0059). The patients in the infrared coagulation group resumed their duties earlier (2 vs 4 days, P = 0.03), but also had a higher recurrence or failure rate (P = 0.03). Thus, we conclude that band ligation, although more effective in controlling symptoms and obliterating hemorrhoids, is associated with more pain and discomfort to the patient. As infrared coagulation can be conveniently repeated in case of recurrence, it could be considered to be a suitable alternative office procedure for the treatment of early stage hemorrhoids.

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history

Preterm delivery is the main cause of neonatal death and ultrasonographic cervical assessment has been shown to be more accurate than digital examination in recognizing a short cervix. This is a cross-sectional study, involving 1131 women at 22-24 weeks of pregnancy, designed to determine the distribution of cervical length and to examine which variables of demographic characteristics and obstetric history increase the risk of a short cervix (15 mm or less). The distribution of maternal demographic and obstetric history characteristics among patients with cervical length £15 mm was analyzed and compared to the findings for the general population. Risk ratios (RR) between subgroups were generated from this comparison. Median cervical length was 37 mm and in 1.5% of cases it was 15 mm or less. The proportion of women with a short cervix (<=15 mm) was significantly higher among patients with a low body mass index (RR = 3.5) and in those with previous fetal losses between 16-23 weeks (RR = 33.1) or spontaneous preterm deliveries between 24-32 weeks (RR = 14.1). We suggest that transvaginal sonographic measurement of cervical length be performed as part of a routine midtrimester ultrasound evaluation. There are specific variables of demographic characteristics and obstetric history which increase the risk of detecting a short cervix at 22-24 weeks.

Towards sustainable transport: A comparison of demographic and behavioural characteristics of Finnish and international car sharing users

SStrong evidence suggests that the climate is changing and that these changes are largely caused by human activities. A consensus exists among researchers that human activity is causing global warming and that actions to mitigate global warming need to be taken swiftly. The transportation sector, which relies heavily on fossil fuel burning and primarily oil, is one of the big contributors to air pollution problems at local, regional and global levels. It is the fastest growing source of greenhouse gas emissions and is estimated to be responsible for nearly a quarter of global energyrelated carbon dioxide emissions. Car sharing is a mobility solution encouraging its users to decrease private car usage in favour of communal transit and environmental goals. The idea of car sharing originates from the aspiration to decrease personal car ownership and to reduce vehicle distance travelled. This thesis seeks to complement the understanding of Finnish car sharing users and their usage through better categorization. Through better categorization and segmentation of Finnish car sharing users the thesis seeks to provide information for improved marketing insight. Research is done on the demographic and behavioural characteristics of Finnish car sharing users and they are compared with international findings about the characteristics of International car sharing users. The main research problem is Are Finnish car sharing users similar to international ones? A theoretical research framework on the determinants of individual car sharing usage is built based on international research about demographic and behaviouristic characteristics. After this a quantitative survey is performed to the customers of a Finnish car sharing organization. The data analysed in the thesis consist out of 532 answers received from the car sharing organizations customers. The data is analysed with descriptive and other exploratory methods, which create an understanding of Finnish car sharing users. At the end of the analysis the demographic and behavioural characteristics of Finnish car sharing users are compared with international ones. The research findings of the thesis indicate that the demographic and behavioural characteristics of Finnish car sharing usage largely follow those of their international counterparts. Thanks to the thesis results the car sharing organization is able to better target their customers through improved marketing insight.

Histopathological characteristics of a novel knock-in mouse prostate cancer model

Prostate cancer is relatively unique to man. There is no naturally occurring prostate cancer in the mouse. Pre-clinical studies involve the establishment of a genetically engineered mouse prostate cancer model with features close to those of the human situation. A new knock-in mouse adenocarcinoma prostate (KIMAP) model was established, which showed close-to-human kinetics of tumor development. In order to determine if the similar kinetics is associated with heterogeneous tumor architecture similar to the human situation, we utilized a new mouse histological grading system (Gleason analogous grading system) similar to the Gleason human grading system and flow cytometry DNA analysis to measure and compare the adenocarcinoma of the KIMAP model with human prostate cancer. Sixty KIMAP prostate cancer samples from 60 mice were measured and compared with human prostate cancer. Flow cytometry DNA analysis was performed on malignant prostate tissues obtained from KIMAP models. Mice with prostate cancer from KIMAP models showed a 53.3% compound histological score rate, which was close to the human clinical average (50%) and showed a significant correlation with age (P = 0.001). Flow cytometry analyses demonstrated that most KIMAP tumor tissues were diploid, analogous to the human situation. The similarities of the KIMAP mouse model with tumors of the human prostate suggest the use of this experimental model to complement studies of human prostate cancer.

Use of magnitude-squared coherence to identify the maximum driving response band of the somatosensory evoked potential

The present study proposes to apply magnitude-squared coherence (MSC) to the somatosensory evoked potential for identifying the maximum driving response band. EEG signals, leads [Fpz'-Cz'] and [C3'-C4'], were collected from two groups of normal volunteers, stimulated at the rate of 4.91 (G1: 26 volunteers) and 5.13 Hz (G2: 18 volunteers). About 1400 stimuli were applied to the right tibial nerve at the motor threshold level. After applying the anti-aliasing filter, the signals were digitized and then further low-pass filtered (200 Hz, 6th order Butterworth and zero-phase). Based on the rejection of the null hypothesis of response absence (MSC(f) > 0.0060 with 500 epochs and the level of significance set at a = 0.05), the beta and gamma bands, 15-66 Hz, were identified as the maximum driving response band. Taking both leads together ("logical-OR detector", with a false-alarm rate of a = 0.05, and hence a = 0.0253 for each derivation), the detection exceeded 70% for all multiples of the stimulation frequency within this range. Similar performance was achieved for MSC of both leads but at 15, 25, 35, and 40 Hz. Moreover, the response was detected in [C3'-C4'] at 35.9 Hz and in [Fpz'-Cz'] at 46.2 Hz for all members of G2. Using the "logical-OR detector" procedure, the response was detected at the 7th multiple of the stimulation frequency for the series as a whole (considering both groups). Based on these findings, the MSC technique may be used for monitoring purposes.

Weld joint characteristics by nano-materials addition

The need for industries to remain competitive in the welding business, has created necessity to develop innovative processes that can exceed customer’s demand. Significant development in improving weld efficiency, during the past decades, still have their drawbacks, specifically in the weld strength properties. The recent innovative technologies have created smallest possible solid material known as nanomaterial and their introduction in welding production has improved the weld strength properties and to overcome unstable microstructures in the weld. This study utilizes a qualitative research method, to elaborate the methods of introducing nanomaterial to the weldments and the characteristic of the welds produced by different welding processes. The study mainly focuses on changes in the microstructural formation and strength properties on the welded joint and also discusses those factors influencing such improvements, due to the addition of nanomaterials. The effect of nanomaterial addition in welding process modifies the physics of joining region, thereby, resulting in significant improvement in the strength properties, with stable microstructure in the weld. The addition of nanomaterials in the welding processes are, through coating on base metal, addition in filler metal and utilizing nanostructured base metal. However, due to its insignificant size, the addition of nanomaterials directly to the weld, would poses complications. The factors having major influence on the joint integrity are dispersion of nanomaterials, characteristics of the nanomaterials, quantity of nanomaterials and selection of nanomaterials. The addition of nanomaterials does not affect the fundamental properties and characteristics of base metals and the filler metal. However, in some cases, the addition of nanomaterials lead to the deterioration of the joint properties by unstable microstructural formations. Still research are ongoing to achieve high joint integrity, in various materials through different welding processes and also on other factors that influence the joint strength.

Identification of characteristics for successful university-company partnership development

The importance of university-company collaboration has increased during the last decades. The drivers for that are, on the one hand, changes in business logic of companies and on the other hand the decreased state funding of universities. Many companies emphasize joint research with universities as an enabling input to their development processes, which aim at creating new innovations, products and wealth. These factors have changed universities’ operations and they have adopted several practices of dynamic business organizations, such as strategic planning, monitoring and controlling methods of internal processes etc. The objective of this thesis is to combine different characteristics of successful university-company partnership and its development. The development process starts with identifying potential partners in the university’s interest group, which requires understanding the role of different partners in the innovation system. Next, in order to find a common development basis, matching the policy and strategy between partners is needed. The third phase is to combine the academic and industrial objectives of a joint project, which is a typical form of university-company collaboration. The optimum is a win-win situation where both partners, universities and companies, can get addedvalue. For the companies added value typically means access to new research results before their competitors. For the universities added value offers a possibility to carry on high level scientific work. The research output in the form of published scientific articles is evaluated by the international science community. Because the university-company partnership is often executed by joint projects, the different forms of this kind of projects is discussed in this study. The most challenging form of collaboration is a semi-open project model, which is not based on bilateral activities between universities and companies but on a consortium of several universities, research institutes and companies. The universities and companies are core actors in the innovation system. Thus the discussion of their roles and relations to public operators like publicly funded financiers is important. In the Finnish innovation system there are at least the following doers executing strategies and policies: EU, Academy of Finland and TEKES. In addition to these, Strategic Centres for Science, Technology and Innovation which are owned jointly by companies, universities and research organizations have a very important role in their fields of business. They transfer research results into commercial actions to generate wealth. The thesis comprises two parts. The first part consists of an overview of the study including introduction, literature review, research design, synthesis of findings and conclusions. The second part introduces four original research publications.

Effects of a PPARG gene variant on obesity characteristics in Brazil

The contribution of genetic factors to the development of obesity has been widely recognized, but the identity of the genes involved has not yet been fully clarified. Variation in genes involved in adipocyte differentiation and energy metabolism is expected to have a role in the etiology of obesity. We assessed the potential association of a polymorphism in one candidate gene, peroxisome proliferator-activated receptor-gamma (PPARGg), involved in these pathways and obesity-related phenotypes in 335 Brazilians of European descent. All individuals included in the sample were adults. Pregnant women, as well as those individuals with secondary hyperlipidemia due to renal, liver or thyroid disease, and diabetes, were not invited to participate in the study; all other individuals were included. The gene variant PPARG Pro12Ala was studied by a PCR-based method and the association between this genetic polymorphism and obesity-related phenotypes was evaluated by analysis of covariance. Variant allele frequency was PPARG Ala12 = 0.09 which is in the same range as described for European and European-derived populations. No statistically significant differences were observed for mean total cholesterol, LDL cholesterol, HDL cholesterol, or triglyceride levels among PPARG genotypes in either gender. In the male sample, an association between the PPARG Pro12Ala variant and body mass index was detected, with male carriers of the Ala variant presenting a higher mean body mass index than wild-type homozygotes (28.3 vs 26.2 kg/m², P = 0.037). No effect of this polymorphism was detected in women. This finding suggests that the PPARG gene has a gender-specific effect and contributes to the susceptibility to obesity in this population.

Clinical, epidemiological, and microbiological characteristics of bacteremia caused by high-level gentamicin-resistant Enterococcus faecalis

Enterococcus spp bacteremia is associated with high mortality and the appearance of high-level gentamicin resistance (HLGR) created additional challenges for the treatment of these infections. We evaluated the epidemiological and clinical characteristics of patients with bacteremias caused by HLGR and non_HLGR Enterococcus faecalis isolates at a teaching hospital in the State of São Paulo, Brazil. Patients with bacteremia due to E. faecalis diagnosed between January 1999 and December 2003 were included in the study. We collected clinical, epidemiological, and microbiological data from medical records. Banked isolates were typed using pulsed-field gel electrophoresis. We identified 145 cases of E. faecalis bacteremia: 66 (45.5%) were caused by HLGR isolates and 79 (54.5%) by non_HLGR. In the univariate analysis, patients with HLGR infection were older, had higher rates of bladder catheterization, and more often had treatment with cephalosporin, quinolone, and/or carbapenem compared with patients with non_HLGR infection (P < 0.05). Multivariate analysis indicated that older age, hematological malignancy, and previous use of vancomycin were independently associated with HLGR (P < 0.05). Mortality rates were not significantly different among patients with HLGR (50%) and non_HLGR (43%) infections (P = 0.40). Of the 32 genotyped isolates, 16 were distributed into 6 main electrophoresis patterns and 16 others had distinct patterns. E. faecalis bacteremia is associated with high mortality and is frequently caused by HLGR isolates at this teaching hospital. The variability among genotyped isolates suggests that endogenous infections, rather than patient-to-patient transmission of E. faecalis, are more common at this institution.