A nationwide, multi-center, retrospective study of symptomatic small bowel stricture in patients with Crohn\u27s disease.

BACKGROUND:Small bowel stricture is one of the most common complications in patients with Crohn\u27s disease (CD). Endoscopic balloon dilatation (EBD) is a minimally invasive treatment intended to avoid surgery; however, whether EBD prevents subsequent surgery remains unclear. We aimed to reveal the factors contributing to surgery in patients with small bowel stricture and the factors associated with subsequent surgery after initial EBD.METHODS:Data were retrospectively collected from surgically untreated CD patients who developed symptomatic small bowel stricture after 2008 when the use of balloon-assisted enteroscopy and maintenance therapy with anti-tumor necrosis factor (TNF) became available.RESULTS:A total of 305 cases from 32 tertiary referral centers were enrolled. Cumulative surgery-free survival was 74.0% at 1 year, 54.4% at 5 years, and 44.3% at 10 years. The factors associated with avoiding surgery were non-stricturing, non-penetrating disease at onset, mild severity of symptoms, successful EBD, stricture length < 2 cm, and immunomodulator or anti-TNF added after onset of obstructive symptoms. In 95 cases with successful initial EBD, longer EBD interval was associated with lower risk of surgery. Receiver operating characteristic analysis revealed that an EBD interval of ≤ 446 days predicted subsequent surgery, and the proportion of smokers was significantly high in patients who required frequent dilatation.CONCLUSIONS:In CD patients with symptomatic small bowel stricture, addition of immunomodulator or anti-TNF and smoking cessation may improve the outcome of symptomatic small bowel stricture, by avoiding frequent EBD and subsequent surgery after initial EBD

宇宙望遠鏡向けミラーへのコーディエライトセラミックスの適用性検討

本稿はコーディエライトセラミックスをミラー母材に適用した場合の特徴について検討した結果を包括的にまとめたものである．本研究の中で各種試験規格に従いコーディエライトセラミックスの材料特性を改めて取得した結果によると，コーディエライトセラミックスは特に比剛性や強度，熱伝導度の観点で従来のガラスセラミックスより優れた結果が得られている．線膨張係数については温度依存性を含めて詳細な特性を取得し，特に室温近辺にて低い値となる結果を得た．また，放射線についても十分な耐性があることを試験的に確認した．製造性については，0.3m級，0.7m級，1.3m級のミラー母材を試作し，可視ミラーとして問題なく使用できることが検証された．これらの結果から，コーディエライトセラミックスは宇宙用望遠鏡のミラー母材として必要な特性を有し，特に軽量大口径の大型ミラーの実現に適しているといえる．This paper summarizes the results of an investigation into the characteristics of cordierite ceramics as a mirror substrate. For this study, the material properties of cordierite ceramics were obtained based on various standards. As a result, cordierite ceramics was found to be superior to glass ceramics in terms of specific stiffness, bending strength, and thermal conductivity. The coefficient of thermal expansion (CTE) indicates a particularly low value near the zero-crossing point at room temperature. Radiation resistance has also been experimentally confirmed. In addition, to assess manufacturability, three mirrors, each was 0.3, 0.7, and 1.3 meters in diameter, were prototyped and verified to be suitable for use as mirrors for visible wavelength. Based on these results, it was revealed that cordierite ceramics have sufficient properties as a mirror substrate for space telescopes and are suitable for lightweight large-diameter mirrors.形態: カラー図版ありPhysical characteristics: Original contains color illustrationsレポート番号: RM-23-00