Self-healing capability of large-scale engineered cementitious composites beams

YesEngineered Cementitious Composites (ECC) is a material which possesses advanced self-healing properties. Although the self-healing performance of ECC has been revealed in numerous studies, only small-scale, laboratory-size specimens have been used to assess it under fixed laboratory conditions and curing techniques. In order to evaluate the effect of intrinsic self-healing ability of ECC on the properties of structural-size, large-scale reinforced-beam members, specimens with four different shear span to effective depth (a/d) ratios, ranging from 1 to 4, were prepared to evaluate the effects of shear and flexural deformation. To ensure a realistic assessment, beams were cured using wet burlap, similar to on-site curing. Each beam was tested for mechanical properties including load-carrying capacity, deflection capacity, ductility ratio, yield stiffness, energy absorption capacity, and the influence of self-healing, by comparing types of failure and cracking. Self-healed test beams showed higher strength, energy absorption capacity and ductility ratio than damaged test beams. In test beams with an a/d ratio of 4 in which flexural behavior was prominent, self-healing application was highly successful; the strength, energy absorption capacity and ductility ratios of these beams achieved the level of undamaged beams. In addition, flexural cracks healed better, helping recover the properties of beams with predominantly flexural cracks rather than shear cracks.The authors gratefully acknowledge the financial assistance of the Scientific and Technical Research Council (TUBITAK) of Turkey provided under Project: MAG-112M876 and the Turkish Academy of Sciences, Young Scientist Award program. The second author would also like to acknowledge the financial support of TÜBITAK for the 2219 Scholarship

A novel modified PAIR technique using a trocar catheter for percutaneous treatment of liver hydatid cysts: a six-year experience

PURPOSEWe aimed to demonstrate the success and reliability of a novel puncture, aspiration, injection, and reaspiration (PAIR) technique in liver hydatid cysts.METHODSPercutaneous treatment with ultrasonographic guidance was performed in 493 hepatic hydatid cysts in 374 patients. Patients were treated with a new PAIR technique by single puncture method using a 6F trocar catheter. The results of this novel technique were evaluated with regards to efficacy and safety of the procedure and complication rates.RESULTSOut of 493 cysts, 317 were Gharbi type I (WHO CE 1) and 176 were Gharbi type II (WHO CE 3A). Of all cysts, 13 were referred to surgery because of cystobiliary fistulization. Recurrence was observed in 11 cysts one month later. Therefore, the success rate of the PAIR technique was 97.7% (469/480). Minor complications (fever, urticaria-like reactions, biliary fistula) were seen in 44 treated patients (12%, 44/374); the only major complication was reversible anaphylactic shock which was observed in two patients (0.5%, 2/374).CONCLUSIONThis novel modified PAIR technique may be superior to catheterization by Seldinger technique due to its efficiency, easier application, lower severe complication rate, and lower cost. Further comparative studies are required to confirm our observations

Merkezkaç Kuvvetiyle Eğirme Yöntemi ile Kemik Doku Mühendisliği Uygulamaları için PHBV Bazlı Kompozit Fiberlerin Geliştirilmesi

Kemik doku hastakları, travma veya cerrahi operasyonlara bağlı olarak meydana gelen kemik doku kayıpları günümüzün en yaygın problemlerinden biridir. Kemik defektleri, defekt alanına konulan uygun biyomalzemeler ile kapatılarak tedavi edilebilmektedir. Çözücü döküm ve partikül uzaklaştırma, gazla köpüklendirme, faz ayrımı, elektroeğirme, 3-boyutlu baskı, eriyik kalıplama, ve dondurup kurutma metotları bu alanda en çok kullanılan yöntemlerdendir. Son zamanlarda, merkez kaç kuvveti kullanarak polimerleri mikro ve nano çapta fiberler olarak bir toplayıcı üzerine dizebilen sistemler üretilmiştir. ‘Rotary jet spinning’ veya ‘Forcespinning’ olarak bilinen bu yöntem, diğer ‘spinning’ yöntemlerine nazaran üretim kapasitesi çok daha fazla olan, taşıyıcı morfolojisi ve fiber çaplarında üniformite kontrolü sunabilen, düşük maliyet ve yüksek verimlilik ile çalışan sistemleri içermektedir. Projede geliştirilecek olan kompozit yapıdaki doku iskelesi, Poli(3-hidroksibütrat-co-3-hidroksivalerat) (PHBV) ve hiyaluronik asit (HYA) karışımından hazırlanmış, hizalandırılmış fiber bazlı bir yapıda olacaktır. Proje kapsamında, ODTÜ’de geliştirilen PHBV-HYA fiber doku iskelelerinin kemik doku rejenerasyon kapasitesinin incelenmesi ve optimize edilmesi planlanmaktadır. Projenin ilk aşaması olarak düşünülen bu bir yıllık süreçte yeni bir yöntemin oturtulması ile doğal ve sentetik iki polimerin birlikte oluşturduğu fiber yapıdaki doku iskeleleri elde edilecek ve özellikleri incelenecektir