Fatigue Damage in Composite Cylinders

In this study, optimal angle-ply orientation of symmetric composite cylinders under fatigue loading is investigated. The fiber-reinforced plastic cylinders were manufactured from E-glass/epoxy. The layers were manufactured symmetrically in [+/- 75 degrees](2), [+/- 60 degrees](2), [+/- 55 degrees](2), and [+/- 45 degrees](2) Orientations. Burst pressure of filament-wound composite cylinders under alternating pure internal pressure was measured experimentally. Internal fatigue pressure testing method was applied to the composite cylinders in closeended condition. For this study, a PLC controlled hydraulic pressure testing machine has been employed. The static burst pressure values of specimens were measured; subsequently, fatigue test pressure was applied in 70, 60, and 50% stress levels of burst pressure for each orientation. Damage propagations of the composite cylinders on these stress levels were observed as whitening, leakage, and final failure for [+/- 60 degrees](2), [+/- 55 degrees](2), and orientations. When the damage propagation of [+/- 75 degrees](2) angle-ply cylinder was observed, whitening and leakage did not occur and final failure occurred suddenly. Stress-cycle curves obtained from the tests are given in graphics. Experimental results reveal that variation in stress levels and the winding angles have considerable effects on final failure cycles, which is also presented graphically. The optimum winding angle for the composite pressure cylinders or vessels under internal fatigue pressure load was obtained as [+/- 45 degrees](2) orientation. POLYM. COMPOS., 31:707-713, 2010. (C) 2009 Society of Plastics Engineer

Safety of clomiphene citrate: a literature review.

Clomiphene citrate (CC) is a nonsteroidal compound and induces ovulation indirectly. The wide usage of the CC raises a question; is it safe or not? In the light of this question, this review aimed to highlight all researches and insights into the association between the use of CC and risk of genotoxicity, cytotoxicity, embryotoxicity, teratogenicity and risk of different cancer types. We conducted a MEDLINE/PubMed, Scopus, Web of Science, Google Scholar search. After a careful screening process of all authors, 32 of these articles were considered as appropriate, and reviewed. Our evaluations showed that CC has genotoxic, cytotoxic, embryotoxic and teratogenic properties. There is no association between the use of CC and risk of ovarian, breast, uterine, cervix, endometrium, lung, colorectal cancer, and lymphoma. However, risk increased especially after 6 cycles of use and especially in nulligravid women. The use of CC should be restricted to 6 cycles. Moreover, malignant melanoma and thyroid cancer risk was found to be higher among CC treated women in almost all studies. Further works should be conducted especially in animal models to assess its risk features

Safety of clomiphene citrate: a literature review

Clomiphene citrate (CC) is a nonsteroidal compound and induces ovulation indirectly. The wide usage of the CC raises a question; is it safe or not? In the light of this question, this review aimed to highlight all researches and insights into the association between the use of CC and risk of genotoxicity, cytotoxicity, embryotoxicity, teratogenicity and risk of different cancer types. We conducted a MEDLINE/PubMed, Scopus, Web of Science, Google Scholar search. After a careful screening process of all authors, 32 of these articles were considered as appropriate, and reviewed. Our evaluations showed that CC has genotoxic, cytotoxic, embryotoxic and teratogenic properties. There is no association between the use of CC and risk of ovarian, breast, uterine, cervix, endometrium, lung, colorectal cancer, and lymphoma. However, risk increased especially after 6 cycles of use and especially in nulligravid women. The use of CC should be restricted to 6 cycles. Moreover, malignant melanoma and thyroid cancer risk was found to be higher among CC treated women in almost all studies. Further works should be conducted especially in animal models to assess its risk features

Znaczenie wyników elektrokardiografii w diagnozowaniu ubytku przegrody międzyprzedsionkowej

Background: Atrial septal defect (ASD) is the most frequent heart defect observed in adulthood. Although it is usually non-symptomatic, it may result in heart failure, arrhythmic complications, and paradoxical embolism-related morbidity or mortality if the diagnosis is late. Aim: This study was planned in order to investigate the importance of electrocardiographic findings in the diagnosis of ASD. Methods: Sixty-one patients with a diagnosis of ASD and 66 healthy volunteers without cardiac disease were enrolled in the study. Electrocardiographs (ECG) were performed on all patients to investigate the presence of right bundle branch block (RBBB), incomplete RBBB, defective T wave (DTW), and notch finding in the R wave of inferior derivations (crochetage R wave). ASD types and diameters were determined via transthoracic and transoesophageal echocardiography. Results: It was determined that incomplete RBBB (56% vs. 5%), DTW (48% vs. 3%), and R wave crochetage (57% vs. 8%) in inferior derivations were more frequent in ASD patients compared to the control group patients. The specificity of the defined ECG findings in the diagnosis of ASD were 95%, 97%, and 92%, respectively. No correlation was detected between the ASD diameter and incomplete RBBB, whereas significant correlation was observed between the ASD diameter and the presence of crochetage R wave (17.5 ± 4.0 mm in patients with crochetage R wave, and 20.9 ± 8.2 mm in patients without crochetage R wave, p = 0.057). Conclusions: Detection of RBBB, DTW, and crochetage R wave in superficial ECG may contribute to early detection in patients with ASD.  Wstęp: Ubytek przegrody międzyprzedsionkowej (ASD) jest najczęstszą wadą serca występującą u osób dorosłych. Zwykle nie powoduje ona objawów, lecz jeśli nie zostanie wcześnie rozpoznana, może być przyczyną niewydolności serca, zaburzeń rytmu i zatorów paradoksalnych oraz związanych z tym śmiertelności i chorobowości. Cel: Celem pracy była ocena znaczenia parametrów elektrokardiograficznych (EKG) w diagnozowaniu ASD. Metody: Do badania włączono 61 chorych z ASD i 66 osób zdrowych (bez chorób serca). U wszystkich pacjentów wykonano badanie EKG w celu sprawdzenia, czy występują: blok prawej odnogi pęczka Hisa (RBBB), niezupełny RBBB, nieprawidłowy załamek T (DTW) i wcięcia w załamku R w odprowadzeniach II, III i aVF (zazębiony załamek R). Typy i wymiary ASD określono za pomocą echokardiografii przezklatkowej i przezprzełykowej. Wyniki: Ustalono, że niezupełny RBBB (56% vs. 5%), DTW (48% vs. 3%) i zazębiony załamek R (57% vs. 8%) w odprowadzeniach II, III i aVF występowały częściej u chorych z ASD niż u osób z grupy kontrolnej. Swoistość określonych cech w EKG w stosunku do rozpoznania ASD wynosiła odpowiednio 95%, 97% i 92%. Nie wykazano żadnych korelacji między średnicą ASD a niezupełnym RBBB, stwierdzono natomiast istotne zależności między średnicą ASD a obecnością zazębionego załamka R (17,5 ± 4,0 mm u chorych z zazębionym załamkiem R i 20,9 ± 8,2 mm u pacjentów bez zazębienia załamka R; p = 0,057). Wnioski: Stwierdzenie RBBB, DTW i zazębionego załamka R w zapisie powierzchniowego EKG może się przyczynić do wczesnego wykrycia ASD.