Convergent and oscillatory solutions in infinite-dimensional synchronization systems

Control systems that arise in phase synchronization problems are featured by infinite sets of stable and unstable equilibria, caused by presence of periodic nonlinearities. For this reason, such systems are often called “pendulum-like”. Their dynamics are thus featured by multi-stability and cannot be examined by classical methods that have been developed to test the lobal stability of a unique equilibrium point. In general, only sufficient conditions for the solution convergence are known that are usually derived for pendulum-like systems of Lurie type, that is, interconnections of stable LTI blocks and periodic nonlinearities, which obey sector or slope restrictions. Most typically, these conditions are written as multi-parametric frequency-domain inequalities, which should be satisfied by the transfer function of the system’s linear part. Remarkably, if the frequencydomain inequalities hold outside some bounded range of frequencies, then the absence of periodic solutions with frequencies in this range is guaranteed, which can be considered as a weaker asymptotical property. It should be noticed that validation of the frequency domain stability condition for a given structure of the known linear part of the system is a self-standing nontrivial problem. In this paper, we demonstrate that a previously derived frequency-domain conditions for stability and absence of oscillations can be substantially simplified, parameters ensuring the corresponding asymptotic property. We demonstrate the efficiency of new criteria on specific synchronization systems

Carbon dioxide balance of subarctic tundra from plot to regional scales

Peer reviewe

52. Development of network of cancer family syndrome registries in eastern Europe

It has been proven that organizing the registries of families affected by CFS is very helpful in research leading to: 1. Identification of new genes of CFS, 2. Better knowledge of correlations in CFS, 3. Identification of external factors having impact on mutated genes, 4. Description of mutation characteristic for particular populations.Thus, development of CFS registries is very important for increasing pre-clinical and clinical research facilities. Direct positive consequence will also be the improvement of quality of life by better management of patients affected by CFS. Without registries these patients are very often not identified and deprived of appropriate recommendations concerning prophylactics, surveillance and treatment. Development of CFS registries leads also to further improvement of quality of life by progress in management in families with these tumours which can be achieved by better organizing of research on CFS. Better management in CFS families decreases also health-care costs by lowering the number of cancers and increasing the number of tumours detected at their earliest clinical stage when the treatment is less expensive.The scientific objectives of the project include:-elaboration of standards for a model cancer family syndrome registries in Eastern Europe-registration of ∼ 2000 families with different types of CFS in populations of East European countries (Czech, Hungary, Latvia, Lithuania, Poland)-initiation of European collaborative studies with the use of material collected by East European CFS registries

Germline MSH2 and MLH1 mutational spectrum in HNPCC families from Poland and the Baltic States.

Peer reviewe

Survival of hereditary non-polyposis colorectal cancer patients compared with sporadic colorectal cancer patients

<p>Abstract</p> <p>Background</p> <p>Patients with hereditary non-poliposys colorectal cancer (HNPCC) have better prognosis than sporadic colorectal cancer (CRC). Aim of our retrospective study was to compare the overall survival between sporadic CRC and HNPCC patients.</p> <p>Methods</p> <p>We analyzed a cohort of 40 (25 males and 15 females) HNPCC cases with a hospital consecutive series of 573 (312 males and 261 females) sporadic CRC observed during the period 1970–1993. In 15 HNPCC patients we performed mutational analysis for microsatellite instability. Survival rates were calculated by Kaplan-Meier method and compared with log rank test.</p> <p>Results</p> <p>The median age at diagnosis of the primary CRC was 46.8 years in the HNPCC series versus 61 years in sporadic CRC group. In HNPCC group 85% had a right cancer location, vs. 57% in the sporadic cancer group. In the sporadic cancer group 61.6% were early-stages cancer (Dukes' A and B) vs. 70% in the HNPCC group (p = ns). The crude 5-years cumulative survival after the primary CRC was 94.2% in HNPCC patients vs. 75.3% in sporadic cancer patients (p < 0.0001).</p> <p>Conclusion</p> <p>Our results show that overall survival of colorectal cancer in patients with HNPCC is better than sporadic CRC patients. The different outcome probably relates to the specific tumorigenesis involving DNA mismatch repair dysfunction.</p

Genotype-phenotype correlations among BRCA1 4153delA and 5382insC mutation carriers from Latvia

<p>Abstract</p> <p>Background</p> <p>Mutations in the high penetrance breast and ovarian cancer susceptibility gene <it>BRCA1 </it>account for a significant percentage of hereditary breast and ovarian cancer cases. Genotype-phenotype correlations of <it>BRCA1 </it>mutations located in different parts of the <it>BRCA1 </it>gene have been described previously; however, phenotypic differences of specific <it>BRCA1 </it>mutations have not yet been fully investigated. In our study, based on the analysis of a population-based series of unselected breast and ovarian cancer cases in Latvia, we show some aspects of the genotype-phenotype correlation among the <it>BRCA1 </it>c.4034delA (4153delA) and c.5266dupC (5382insC) founder mutation carriers.</p> <p>Methods</p> <p>We investigated the prevalence of the <it>BRCA1 </it>founder mutations c.4034delA and c.5266dupC in a population-based series of unselected breast (n = 2546) and ovarian (n = 795) cancer cases. Among the <it>BRCA1 </it>mutation carriers identified in this analysis we compared the overall survival, age at diagnosis and family histories of breast and ovarian cancers.</p> <p>Results</p> <p>We have found that the prevalence of breast and ovarian cancer cases (breast: ovarian cancer ratio) differs significantly among the carriers of the c.5266dupC and c.4034delA founder mutations (OR = 2.98, 95%CI = 1.58 to 5.62, P < 0.001). We have also found a difference in the prevalence of breast and ovarian cancer cases among the 1^stand 2^nddegree relatives of the c.4034delA and c.5266dupC mutation carriers. In addition, among the breast cancer cases the c.4034delA mutation has been associated with a later age of onset and worse clinical outcomes in comparison with the c.5266dupC mutation.</p> <p>Conclusions</p> <p>Our data suggest that the carriers of the c.4034delA and c.5266dupC founder mutations have different risks of breast and ovarian cancer development, different age of onset and prognosis of breast cancer.</p

Prevalence of the most frequent BRCA1 mutations in Polish population

The purpose of our study was to establish the frequency and distribution of the four most common BRCA1 mutations in Polish general population and in a series of breast cancer patients. Analysis of the population frequency of 5382insC (c.5266dupC), 300T >G (p.181T >G), 185delAG (c.68_69delAG) and 3819del5 (c.3700_3704del5) mutations of the BRCA1 gene were performed on a group of respectively 16,849, 13,462, 12,485 and 3923 anonymous samples collected at birth in seven Polish provinces. The patient group consisted of 1845 consecutive female breast cancer cases. The most frequent BRCA1 mutation in the general population was 5382insC found in 29 out of 16,849 samples (0.17%). 300T >G and 3819del5 mutations were found in respectively 11 of 13,462 (0.08%) and four of 3923 (0.1%) samples. The population prevalence for combined Polish founder 5382insC and 300T >G mutations was 0.25% (1/400). The frequencies of 5382insC and 300T >G carriers among consecutive breast cancer cases were, respectively, 1.9% (35/1845) and 1.2% (18/1486). Comparing these data with the population frequency, we calculated the relative risk of breast cancer for 5382insC mutation at OR = 17 and for 300T >G mutation at OR = 26. Our results, based on large population studies, show high frequencies of founder 5382insC and 300T >G BRCA1 mutations in Polish general population. Carriage of one of these mutations is connected with a very high relative risk of breast cancer