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本研究では、TNF-αを含む炎症性サイトカインが音響障害による難聴に関連していることを踏まえ、TNF-αを標的とするモノクローナル抗体であるアダリムマブが、激しい音響への暴露から内耳を保護する可能性を検討した。本研究では、アダリムマブをマウスに投与し、内耳への影響を評価するとともに、アダリムマブの内耳への移行、聴器毒性、音響暴露への影響に関する実験も行った。実験結果から、アダリムマブは投与後に蝸牛に部分的に到達したが、音響暴露に対する感受性を高め、内耳での有毛細胞の損失が増加したことが示された。TNF-αは潜在的な治療標的になりうると考えられていたが、本研究結果からはTNF-αの過剰な抑制が内耳に悪影響を与える可能性があることが示唆された。本研究では、抗マウスTNF-α抗体の代わりに抗ヒトTNF-α抗体であるアダリムマブを使用したことや、内耳の保護を改善するために他のサイトカインの抑制を検討する必要性があることなど、いくつかの限界があることを認識している。結論として、アダリムマブの投与は、おそらく過度の TNF-α抑制により、音響暴露に対する内耳の感受性を高め、より重大な有毛細胞の損傷を引き起こす可能性があることが判明した。
Creators : 山本 陽平
目的:日本人のジェノタイプ1型C型慢性肝炎患者を対象に、異なる肝臓の線維化ステージで治療を開始する場合の、3 種類の直接作用型抗ウイルス薬(DAA: sofosbuvir-ledipasvir(SL)、glecaprevir-pibrentasvir(GP)、elbasvir plus grazoprevir(E/G))における費用対効果の評価を行うことを目的とした。 方法:異なる線維化ステージで適用される治療戦略の費用対効果を評価するために、線維化ステージの進行を反映した判断モデルを作成した。すなわち、線維化ステージに関係なく全ての患者を治療する戦略(TA)、肝線維化進行の4つのステージ以上の患者を治療する戦略(F1S:ステージF0 では治療を控え、ステージF1以上の患者に治療を開始、同様にF2S、F3S、F4Sではそれぞれのステージ以上の患者に治療を開始)、抗ウイルス剤治療を行わない(NoRx)の6つの治療戦略を比較した。費用対効果は、一生涯の時間水平で、日本における医療保険支払い者の視点で検討を行った。 結果:基本分析では、線維化が進行したステージF2の患者で治療開始する戦略(F2S)と比較して、全ての患者への治療を行う戦略(TA)において、SL、GP、E/G それぞれの質調整生存年(QALY)の増加分は0.32〜0.33であった。また、QALYあたりの増分費用効果費(ICER)はそれぞれ、24,320 米ドル、18,160 米ドル、17,410米ドルであった。費用対効果許容度曲線では、50,000米ドルの支払意思閾値においてTAが最も費用対効果が高く、3つのDAAともその支払意思閾値以内であった。 結論:日本人のジェノタイプ1型C型慢性肝炎患者において、線維化ステージに関係なく、すべての患者へ直接作用型抗ウイルス薬治療を行うことが、通常の条件下では費用対効果に優れていることが示唆された。
Creators : 末永 利一郎
Many mail filtering methods have been proposed, but they have not yet achieved perfect filtering. One of the reasons for this is the influence of modified words created by spammers to slip through the mail filtering, in which words are modified by insert symbols, spaces, HTML tags, etc. For example,“ price$ for be$t drug$! ”,“ priceC I A L I S ”, “ <font>se</font>xu<font>al</font> ”, etc. These are frequently replaced with new strings by changing the combination of symbols ,HTML tags etc. Mail filtering is a technique that captures trends in words in training mails (mails received in the past) and applies these trends to words in test mails (newly received emails). Some of the above modified words appear in both training and test mails, i.e., words that could be used as features of spam mail by using them unprocessed, while others appear only in test mails, i.e., words that have not been learned and require special processing (e.g., removal of symbols, search for similar words, etc.) for their use. However, existing methods do not make these distinctions and treat them in the same way. Therefore, in order to bring the filtering performance of the existing methods closer to perfect filtering, we developed a method in which the above modified words are separated into words that appear in both training and test mails and words that appear only in test mails, and each of these words is used for mail filtering. In this study, we treat the above modified words as ”strange words”. Typical examples of such strange words include, in addition to the above, new words included in ham mails, proper nouns used in close relationships, and abbreviations. The results of this study are as follows (1) In order to compare the filtering performance between strange words and other words, filtering experiments were conducted using existing methods with strange words, nouns, verbs, and adjectives. The results showed that the filtering performance of the strange words was the best. This means that strange words have a significant impact on the filtering performance, and we expect to improve the filtering performance of existing methods by developing a new method to utilize strange words. (2) In order to examine the breakdown of strange words, we counted the number of words that appeared in both training and test mails, and the number of words that appeared only in test mails. The results were compared with those obtained for nouns, verbs and adjectives. We found that there are a significant number of strange words that appear in both training and test mails, but only in one of the groups, i.e., ham or spam mail. Words with this appearance pattern are most useful for mail filtering. On the other hand, we found that there are many strange words that appear only in test mails, i.e., words that cannot be learned. We expect to improve the filtering performance by separating these strange words and developing a new method to use each of them. (3) For the use of strange words, we developed (A) a method for using words that appear in both training and test mails, and (B) a method for using words that appear only in test mails, respectively. (A) To examine the breakdown of strange words that appear in both training and test mails, we divided them into two categories: words that appear only in ham and spam mails, i.e., words with patterns that improve filtering performance, and words that do not, and examined their frequency of occurrence. The results showed that the words with appearance patterns that improve filtering performance tend to appear more frequently than those without such patterns. This means that by using words with a certain number of occurrences in filtering, it is possible to use more words that improve filtering performance. We developed a method to do this and conducted experiments with different threshold values to find the optimal value, and confirmed that setting the threshold around 7 improves filtering performance. (B) We compared the number of strange words that appear only in the test mails between ham and spam mails, and found that the number tends to be higher in spam mail than in ham mail. In order to utilize this difference for filtering, we proposed a method to set a uniform spam probability for strange words that appear only in the test mails, and attempted to find the optimal spam probability. As a result, setting the spam probability to 0.7 improved the filtering accuracy from 98.2% to 98.9%. By using (A) and (B) above together, both words that appear in both training and test mails and words that appear only in test mails can be used for mail filtering to increase accuracy. Mail filtering has been improved and its performance has reached its limit. In order to further improve accuracy, i.e., to approach perfect filtering, a new perspective is needed, and this paper provides one such perspective: the use of strange words. This paper is organized as follows. In Chapter 1, we review the background of mail filtering methods, discuss how spammers use strange words to slip through such filters. The purpose and structure of this paper are then presented. In Chapter 2, we will discuss related research on examples of filtering methods that have been proposed so far are given. In Chapter 3, we describe the mail datasets, word handling, and strange words used in the this paper. This is followed by an explanation of the ROC curve, which is the measure used to evaluate the filtering performance, and explanation of scatter plots and box-and-whisker plots. In Chapter 4, we compare the filtering performance between strange words and other words, and show that strange words have a significant impact on the filtering performance. Furthermore, based on the results of a breakdown of the number of strange words, we discuss the possibility of improving filtering performance by separating words that appear in both training and test mails from those that appear only in the test mails. We will work on this in the next chapters and report the results. In Chapter 5, we develop a method to use (A) above, i.e., strange words that appear in both training and test mails. From the results of counting the number of words used in the subject and body of each email, we show that the number tends to be smaller for words that degrade the filtering performance. Based on these results, we propose a method that sets a threshold for the number of words used in the subject and body of mails, and uses only those words that exceed the threshold for classification. Experiments are conducted to find the optimal value by varying the threshold, and the effect of this method on performance is reported. In Chapter 6, we develop a method to use (B) above, i.e., strange words that appear only in the test mails. We compare the number of types of these words in ham and spam mails, and show that the number tends to be larger in spam mails, and that this feature can be used as a bias for detecting spam mails. In this paper, we deal with experiments using bsfilter and develop a method to set spam probabilities uniformly for strange words that appear only in the test mails. After searching for the optimal spam probability, we report that a spam probability of 0.7 greatly improves the filtering performance. In Chapter 7, we describes the processing flow combining the methods developed in Chapter 5 and Chapter 6. The paper is then summarized, including future prospects.
Creators : Temma Seiya
Steel truss bridges, which are one of the bridge structures applicable to long spans, are widely used as marine bridges connecting mainland and remote island. Since such steel truss bridges are built on the sea, they are exposed to severe corrosive environment due to the influence of airborne salt. In addition, there are many parts where it is not easy to inspect to detect abnormalities, so it is more difficult to eliminate the risk of member damage in such steel truss bridges than in general bridges. On the other hand, once the marine bridges are built, they become an indispensable facility for the life of the island. Therefore, if there are no other traffic routes to access an island, the sustainability of the marine bridge is an important issue that is directly linked to the sustainability of the remote island life. When member damage occurs in a steel truss bridge, it depends on redundancy, which means the margin for the load-bearing capacity and load-bearing function, whether the damage develops into chain damage or remains limited damage. Bridges with redundancy could be restored by repairing even if the member damages occurred, because they did not develop into chain damages. In some cases, vehicles could pass through with traffic restrictions. Although redundancy is an important performance for maintaining life on remote islands that have no alternative traffic routes, there are few studies on evaluation and improvement methods of redundancy for long steel truss bridges used for marine bridges. The purpose of this study is to propose a method for improving the redundancy of long steel truss bridges, and three research subjects are set to achieve this purpose. The first study subject is the investigation of the effect of truss joint modeling on redundancy evaluation, and is the subject to appropriately evaluate the redundancy of steel truss bridges. The second is also the subject related to the redundancy evaluation of steel truss bridges, and is the development of dynamic response calculation method that considers the vibration characteristics of steel truss bridges, which are vibration systems with multiple degrees of freedom. The third study subject is a proposal for methods to improve the redundancy of long steel truss bridges. This paper consists of five chapters. Chapter 1 is an introduction, and describes the background of the research, the setting of the purpose and research subjects, and the previous studies. Chapter 2 describes the study on the modeling of the truss joint. In the analysis of healthy steel truss bridges with no member damage, the sectional forces can be calculated appropriately even with analysis modeling in which frame elements of truss members are rigidly connected at the truss joints, simply. On the other hand, in the redundancy analysis of steel truss bridges with member damages, it is shown that it is necessary to consider the shape of the gusset plates at the truss joints in analysis modeling. Chapter 3 describes the study on the calculation method of dynamic response caused by damage of truss members. There are cases where the dynamic response due to member damage is calculated in the same way as a single-degree-of-freedom vibration system. However, this study develops a dynamic response calculation method considering the vibration characteristics of long steel truss bridges by using the eigenvector of steel truss bridges with member damage. A method is proposed to set the magnitude of the eigenvector using balance equation of the work given to the steel truss bridge by the sectional force unloaded from damaged member and the strain energy stored in the steel truss bridge. In addition, a method is proposed to calculate the dynamic response by setting the range of vibration modes using the sum of effective mass ratio, and selecting the eigenvector that has the greatest effect on the dynamic response for each member. It is shown that the proposed calculation method gives redundancy evaluation closer to time-history-response analysis than the method that calculates the dynamic response in the same way as a single-degree-offreedom vibration system. Chapter 4 describes the study on redundancy improvement for a long steel truss bridge. A combination of the countermeasure against members that trigger chain damage and the countermeasure against members with insufficient load-bearing capacity is planned. Analysis clarifies that the X bracing, which is a reinforcing structure in X shape, is an efficient reinforcement that works against multiple member damage cases as the countermeasure against the trigger member of member chain damage. Also, the load-bearing capacity is verified by a loading test of specimens with reinforced structures. Since the subject bridge has 18 truss panels where X bracing can be installed, the placement patterns were examined by the optimization method. It is clarified that the weight of reinforcing material can be reduced by installing X-braces only at four truss panels in the alternating areas, rather than installing at all 18 truss panels. Chapter 5 describes the summary of this study and future developments.
Creators : Tajima Keiji
アミノグリコシド系抗菌薬は有害反応として聴覚障害をきたすことがあり、蝸牛基底回転の外有毛細胞が障害されやすいことが知られている。本研究では、ネオマイシンの有毛細胞障害に対するアスタキサンチンナノ製剤の保護効果を検討した。ネオマイシンを加えたCBA/Nマウスの卵形嚢培養に対し、培養液にアスタキサンチンナノ製剤を投与した群では有毛細胞の減少および酸化ストレスが有意に抑制された。さらに、アスタキサンチンナノ製剤の鼓室内投与を行い音響曝露前後の聴性脳幹反応(ABR)閾値の変化、有毛細胞減少率を評価した。アスタキサンチン投与群では音響曝露後のABR閾値変化、有毛細胞減少率が抑制される傾向が見られた。血液内耳関門の存在により、鼓室内投与に適した薬剤は限られるが、アスタキサンチンナノ製剤の形態は正円窓膜を浸透する可能性があり、内耳障害抑制の効果を有する可能性が示唆された。
Creators : 小林 由貴
The development and implementation of industrial policy are essential in shaping a country’s economic landscape. It promotes industrialization, which, in turn, generates employment opportunities, enhances productivity, and diversifies the economy. the present dissertation studies the subject of industrial policy, with a particular emphasis on resource allocation and computable general equilibrium in Ghana. Chapter 2 delves into the concept of industrial policy and its implementation in Africa in general, and Ghana, in particular. First, we examine Ghana’s past experience with industrial policy implementation and the reasons for its inability to attain the desired outcomes. Subsequently, in response to the call for a return to industrial policy, we argue in favor of a renewed implementation of industrial policy in Ghana. We posit that the likelihood of success is significantly higher with the benefit of better institutions. Chapter 3 examines the subjects of firm-level productivity, productivity distribution, and resource allocation. In the first instance, we decompose labor productivity in Ghana and draw the conclusion that within-sector resource allocation primarily drives productivity growth, with structural change playing a limited role. Next, we analyze the gross allocative effect, finding evidence that resources are migrating toward sectors of lower productivity. Finally, we also examine productivity distribution through the lens of the power law distribution, establishing that firms involved in international trade exhibit higher levels of aggregation. Thus, allocating resources to such firms leads to greater productivity, thereby minimizing resource misallocation. Chapter 4 presents a dynamic recursive computable general equilibrium for Ghana, employing a Social Account Matrix (SAM) with 2015 as the benchmark year, and we conclude this chapter with a brief analysis of SAM. Chapter 5 examines several possible simulation scenarios. We build our simulations around two industrial policy strategies: labor-intensive and capital-intensive, furthermore our simulation is informed by Ghana’s industrial policy plan. We analyze various policies such as efficiency improvement, trade protection, free trade, and taxation policy. We conclude that capital-intensive industrialization would work better under a free trade policy. Moreover, we discovered that the cost of protecting labor-intensive industries is less than the cost of safeguarding capital-intensive industries. We conclude the dissertation with a discussion of the implications of our findings. we aim to provide a comprehensive discussion of the implications of our findings, as well as acknowledge the limitations of our study and propose potential avenues for further research. By doing so, we hope to contribute to the existing body of knowledge in our field and inspire future researchers to expand upon our work.
Creators : Borges Jorge Tavares