京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20975号 / 医博第4321号 / 新制||医||1026(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 川上 浩司, 教授 鈴木 茂彦, 教授 開 祐司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Introduction: Overweight and obesity are associated with onset and progression of atrial fibrillation (AF). Catheter ablation is considered a safe and curative therapy in advanced stages of AF.In this retrospective study wewanted toinvestigate the impact of overweight and obesity on AF-recurrence after ablation,in patients with symptomatic AF undergoing successful elective catheter ablation.Methods:The study population included 90 patients with symptomatic AF who received elective catheter ablation at University Hospital Örebro between 2015-2016. Patients were categorized into 3 study groups: Lean (<25.0 kg/m2), Overweight (25.0-29.9 kg/m2) and Obese (≥30 kg/m2). Recurrence was defined as clinical symptoms and electrocardiogram (ECG)recording consistent with AF within 3 -12 months after ablation.Fisher’s exact test was used to compare AF-recurrence between BMI groups. Results:Out of 90 patients included, 3 were excluded due to missing data. BMI-categories consisted of 17 (19.6%) lean, 47 (54.0%) overweight and 23 (26,4%) obesepatients. Recurrence rates in the different groups were 5.9% in the lean group, 29.8%in the overweight group and 17.4% in the obese group.Compared to lean patients, AF-recurrence was statistically significantly higher in the overweight population (p=0.04), but not in the obese population (p=0.3). BMI was not an independent predictor of AF-recurrence after ablation in the univariate (p=0.52) and multivariate logistic regression analysis (p=0.18).Conclusion:Compared to lean patients,recurrence of AF after catheter ablation was statistically significantly higher in overweight patients, but not in obese patients. BMI seemed not to be an independent predictor of AF-recurrence.

Indiana University-Purdue University Indianapolis (IUPUI) / Objective: To investigate the effect of the size of the space between the restoration and the dentinal wall of the tooth (i.e. the dentinal portion of the gap) on the development of secondary caries. Methods: Tooth-resin-matrix composite specimens were mounted on custom-made gap-model stages. Specimens were divided into four groups (n=10). Group 1 had a uniform gap size of 30μm throughout both enamel and dentin. Group 2 had a 30μm enamel gap size with a 530μm dentinal gap. Group 3 had 525μm gaps in both enamel and dentin. Group 4 had 525μm and 1025μm gaps in enamel and dentin, respectively. Specimens were attached to plastic Petri plates, gas-sterilized and then incubated in a microbial caries model with S. mutans TH16 in (1% sucrose tryptic soy broth for 1 h, 4 times/day, and with a buffer solution for the rest of the day). After 8 days of incubation, tooth specimens were sectioned and stained with a rhodamine B solution. Digital images were taken under a confocal microscope and analyzed for lesion size at the enamel outer lesion (EOL), enamel wall lesion (EWL), dentin wall lesion next to the DEJ (DWL-A) and dentin wall lesion at 750µm from the DEJ (DWL-B). Results: No difference in EOL size was found between the groups. DWL-A and -B were larger in group 3 than groups 1and 2. Larger DWL-B was found in group 3 than group 4. Group 4 had marginally significant larger EWL than groups 1 and 2 (p=0.0652 and p=0.0648, respectively). Also, group 4 had marginally significant (p=0.0607) larger DWL-B than group 1. Conclusions: Based on the results of this study, it can be concluded that the presence of additional space at the dentinal wall area did not affect secondary caries development as long as the enamel gap was small. However, with enamel gaps of ≈500 µm, the presence of the additional gap space at the dentinal wall led to the development of smaller dentinal wall lesions at the deeper parts of the simulated cavity. Also, in uniform gaps, the size of the interface was positively correlated with size of the dentinal wall lesions.

Introduction: Oropharyngeal cancer (OPC) is a highly prevalent malignancy worldwideaffecting the tonsils, the soft palette and the base of the tongue. OPC has a high risk ofrecurrence. Patients are offered a 5-year follow-up program in order to discover earlyrecurrences. However, there exists some controversy regarding the benefit of this follow-up indetecting early recurrences. Objective: The primary aim of this study was to investigate whether recurrences of OPC weredetected in patient-initiated appointments or during routine follow-up. The secondary aim wasto compare the survival between these groups. Method and materials: This study is a retrospective cohort study regarding recurrencedetection among patients diagnosed with OPC. The Örebro Head- and neck cancer registerwas used to identify patients with recurrence of OPC. Additional data was collected frommedical records. Results: A total of 75 patients were included. Routine follow-up detected 50.7% ofrecurrences while patient-initiated visits detected 42.7% of recurrences. No statisticallysignificant difference was found in survival between these groups Conclusion: In contradiction to our hypothesis most of the recurrences were detected atroutine follow-up. There was no statistically significant difference in survival between thetwo ways of detection. These results indicate that our current follow-up program has animportance in detecting early recurrences and should not be altered.

[pt] Os codificadores universais via recorrência de padrões surgiram nos anos 70, quando foram propostos os codificadores lz77 e lz78. Devido a baixa complexidade computacional e ao bom desempenho, quando aplicados na compressão de arquivos de dados, estes codificadores se tornaram extremamente populares. Embora estes codificadores sejam universais, i.e., possuam taxas de compressão que convergem para entropia, recentemente foi mostrado que as taxas de compressão não convergem da forma mais rápida possível, nem mesmo para a classe de fontes sem memória. A redundância de um codificador universal C, dada por R, mede a rapidez com que a taxa de compressão converge para a entropia. Para fontes com número de estados finito, enquanto os melhores resultados de codificadores universais via recorrência de padrões apresentam uma redundância da ordem de 1/{log n}, existem codificadores que atingem uma redundancia de {log n} /n. Portanto, os codificadores via recorrência de padrões não são ótimos. Embora seja conhecido codificadores ótimos segundo o critério da redundância, tais codificadores possuem uma alta complexidade computacional e são pouco úteis na prática. Dentre os codificadores via recorrência de padrões, o codificador lz78 possui uma das mais baixas redundâncias para a classe de fontes com número de estados finito. De fato, não existe outro codificador desta classe, tal que a redundância seja melhor que a do lz78. Tomando como base o lz78, este trabalho propõe novas técnicas para acelerar a convergência da taxa de compressão (diminuir a redundância) dos codificadores universais via recorrência de padrões, para fontes com número de estados finito. Estas técnicas dão origem a novas versões do lz78. As redundâncias das novas versões são estabelecidas, considerando a classe de fontes com número de estados finito. Estas versões são aplicadas na compressão de arquivos de dados, e os resultados obtidos são comparados com os resultados de versões anteriores. / [en] The string matching encoders were proposed about 20 years ago, when the lz77 and lz78 were introduced. They became extremely popular because of the relationship between their low complexity and their good performance. Although these encoders are universal, that is, their compression rates converge to the source entropy, it was shown, recently, that those rates do not converge as fast as possible, even for the class of memoryless source. The redundancy of an unversal encoder C, denoted by Rc, measures how fast the compression rate converge to the entropy. In the class of Finite State Machine (FSM) source, while the best result of the string matching encoders is O 1/ {log n}, there are encoders which achieve a redundancy of O {log n}/n. Therefore, the string matching encoders are not optimal. Even though optimal encoders are known, in general, those encoders have a high complexity and are not useful in practice. Considering the class of string matching encoders, the lz78 has one of the best results over the class of FSM source. In fact, there is no encoder based on the string matching, which archives a better redundancy. This work makes use of the lz78 encoder to propose new techniques to improve the performance of sting matching encoders over the class of FSM. These techniques bring up new versions of the lz78. For the class of FSM, the redundancies of this versions are stablished. These versions are used to compress data files, and their perfoermances are compared to the performances of older versions.

The anticardiolipin antibody syndrome is relatively uncommon. It should be suspected mostly in young people with unexplained embolic or thrombotic events. A young patient with an abnormal prothrombin time, partial thromboplastin time, or venereal disease research lab test with one of the above noted vascular events would be a suspect for this disorder. Though an antibody test that will qualitatively and quantitatively measure antiphospholipid antibodies is available, its clinical application is not entirely clear. The presence of the antibody will support a diagnosis but cannot be used alone for diagnosis or treatment.

We examine results concerning the generation of primes in certain types of integer sequences. The sequences discussed all have a connection in that each satisfies a recurrence relation. Mathematicians have speculated over many centuries that these sequences contain an infinite number of prime terms, however no proof has been given as such. We examine a less direct method of showing an infinitude of primes in each sequence by showing that the sequences contain an infinite number of terms with primitive divisors.

In 1939, I.M. Sheffer proved that every polynomial sequence belongs to one and only one type. Sheffer extensively developed properties of the B-Type 0 polynomial sequences and determined which sets are also orthogonal. He subsequently generalized his classification method to the case of arbitrary B-Type k by constructing the generalized generating function A(t)exp[xH1(t) + · · · + xk+1Hk(t)] = ∑∞n=0 Pn(x)tn, with Hi(t) = hi,iti + hi,i+1t i+1 + · · · , h1,1 ≠ 0. Although extensive research has been done on characterizing polynomial sequences, no analysis has yet been completed on sets of type one or higher (k ≥ 1). We present a preliminary analysis of a special case of the B-Type 1 (k = 1) class, which is an extension of the B-Type 0 class, in order to determine which sets, if any, are also orthogonal sets. Lastly, we consider an extension of this research and comment on future considerations. In this work the utilization of computer algebra packages is indispensable, as computational difficulties arise in the B-Type 1 class that are unlike those in the B-Type 0 class.