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Article
Nugget mechanical properties of combination (rectangular and round) welded and soldered stainless steel wires

Authors: Zainab M. Hasan --- Fakhri A. Ali فخري عبد علي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 3 Pages: 169-173
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study aimed to compare the mechanical properties between four groups of newly fabricatedcombination wires according to their method of union, according to the gauges of wires and a comparison weremade between them and their originals.Materials and method: A total of 60 stainless steel combination wires were fabricated , divided into four groupsaccording to gauge of wires and their method of union, each of them with 15 samples, the groups were welded(0.016x0.022-0.016 and 0.016x0.022-0.018) and soldered (0.016x0.022-0.016 and 0.016x0.022-0.018), samples weremade according to certain parameters which were : for the welded samples: length,weight, duration of pulsationand size of copper electrode tips used; for the soldered samples: length, weight, distaince from the heat source andduration of heat applicationResults: The descriptive statistics showed that the maximum value for ultimate force and ultimate tensile strength wasfor the soldered 0.016x0.022+0.018 inches combination wires, while the minimum was for the welded0.016x0.022+0.016inches wires. Elastic modulus showed higher values for the soldered 0.016x0.022+0.016 and resiliencyvalues for the welded 0.016x0.022+0.016 were the highest. Comparison between combination wires and theiroriginals showed a decrease in the mechanical properties after soldering and welding.Conclusion: Higher gauge wires and soldering method of union showed better mechanical properties than the othergroups and both soldering and welding method showed changes in the mechanical properties of the newlyfabricated wires when comparing them with their originals

المقدمة: تھدف ھذه الدراسة إلى المقارنة بین الخواص المیكانیكیة بین أربع مجموعات من الأسلاك المركبھ وفقا لطریقتھم في الاتحاد،وفقا لقیاسات الأسلاك وتم إجراء مقارنة بینھاوبین الاسلاك الاصلیھ.المواد والطریقھ: مجموعھ من 60 سلك مصنوع من مادة الفولاذ المقاوم للصدأ ، قسمت الى أربع مجموعات وفقا لقیاسات الأسلاك وطریقةاللحام، كل واحد منھم یتكون من 15 عینة،0.022 ) وفقا لبعض الضوابط والتي كانت: الطول، الوزن،ومدة النبض وحجم نحاس االاقطاب x0.016+ 0.022 و 0.018 x0.016+ تم لحم الاسلاك ذات القیاسات التالیھ ( 0.016المستخدمة (بلنسبھ للعینات الملحومھ عن طریق التیار الكھربائي) ومدة عملیة اللحام والبعد من مصدر الحراره (للعینات الملحومھ عن طریق الحراره).0.018-0.022 ) قیم عالیة بالمقارنة مع العینات الاخرى الاقل × النتائج:أظھرت النتائج للقوه القصوى المحتملھ ولقوة الشد القصوى للعینات الملحومھ عن طریق الحراره ( 0.0160.016-0.022 ) قیم عالیھ بلمقارنھ مع العینات الاخرى × حجما والملحومة عن طریق التیار الكھربائي, و اظھرت نتائج معامل المرونھ للعینات الملحومھ عن طریق الحراره( 0.016(0.016 -0.022 × الاكبر حجما الملحومھ عن طریق التیار الكھربائي , اما نتائج معامل الطاقھ المخزونھ فقد اظھرت قیم عالیھ للعینات الملحومھ عن طریق التیار الكھربائي ( 0.016وقد لوحظ انخفاضا في الخواصالمیكانیكیھ عند مقارنة الاسلاك المركبھ مع الاسلاك الاصلیة قبل اللحیم.الخلاصةأظھرت الأسلاك ذات القیاس الأعلى وأسلوب لحام عن طریق الحراره خواصامیكانیكیة أفضل من المجموعات الأخرى وعلى حد سواء عند مقارنة الاسلاك الجدیده مع النسخ الأصلیةالخاصة بھم اظھرت النتائج انخفاضا في الخواصالمیكانیكیھ بلنسبھ للاسلاك المركبھ الجدیده.


Article
Glimpse on Hemostatic Changes Produced By Plasmapheresis

Authors: Haider H. AL-Shammari --- Mayada S. Al-Niami --- Zainab M. Hasan
Journal: Journal of the Faculty of Medicine مجلة كلية الطب ISSN: PISSN: 00419419 / EISSN: 24108057 Year: 2010 Volume: 52 Issue: 2 Pages: 161-168
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Aphaeresis is a term that means to separate or to take away. The basic idea of aphaeresis is efficient removal of a circulating cellular blood component, either cells (Cytopheresis) or plasma solute (plasmapheresis, plasma exchange).Thus, the treatment goal of aphaeresis is to remove the circulating cell or substance directly responsible for the disease process. Acceleration and development of aphaeresis applications had taken place with the arrival of automated cell separators in 1970s that ensure selectively removal of one or more of blood components from the blood and return the remainder to the individual. Plasmapheresis is separation of plasma from blood cells which are returned to the body. It is accompanied by multiple changes in haemostatic system. As many coagulation factors are removed during procedure, changes in selective parameters: Prothrombin Time (PT), Partial Thromboplastin Time (PTT), Thrombin Time (TT), Fibrinogen (FNG) & platelets count are found when the replacement fluids devoid from coagulation factor are used.
Patients and Methods: This clinico-haematological study conducted during a period of six months, from February 2004 to July 2004 at the National Blood Transfusion Center (NBTC) in Baghdad & 50 patients underwent Therapeutic Plasma Exchange (TPE) for various disorders with the use of two types of automated blood cell separators (Haemonetics MCS + which represent an intermittent flow centrifugation technique – IFC & Fresenius AS. TEC 204 which represent the continuous flow centrifugation technique - CFC) in this study, but no instrument type influenced the coagulation screening tests.
Results: The changes in all selective parameter: Prothrombin Time (PT), Partial Thromboplastin Time (PTT), Thrombin Time (TT), Fibrinogen (FNG), Platelets count, Haemoglobin (Hb) and Packed Cell Volume (PCV) were significant after Therapeutic Plasma Exchange (TPE). There was no significant difference in changes in crystalloid group from that in Fresh Frozen Plasma group. In crystalloid group, significant correlation was observed between Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Thrombin Time (TT) & volume of Plasma Exchanged (PE) /session, while spacing between sessions and the number of sessions is significantly correlated with Thrombin Time (TT). Plasma fibrinogen concentration and platelets count were decreased in the patients included in our current study.
Conclusion: There is no significant difference in changes in haemostatic system whether crystalloid or diluted Fresh Frozen Plasma (FFP) was used as replacement fluid. Thus, crystalloid, solution devoid of coagulation material can be used as a replacement fluid in the Therapeutic Plasma Exchange (TPE) if the volume of Plasma Exchanged (PE) is small. These results are of vital importance from the practical & public health point of view in minimizing the usage of blood components((i.e. Fresh Frozen Plasma (FFP) which is a potential source of Transfusion Transmissible Infections (TTIs) worldwide)) & replaced by crystalloid solution as a safer replacement fluid substitute in Therapeutic Plasma Exchange (TPE) process.

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