641 research outputs found

    Chest wall reconstruction still has place in Today’s modern practice:" a tertiary center experience"

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    Background: The key factor following chest wall resection is the preservation of the stability and integrity of the chest wall to support the respiration and protect the underlying organs. The present study aims to evaluate the use of the available grafts and prosthetic materials at our center in chest wall reconstruction with adherence to the proper surgical techniques, good perioperative and postoperative care to obtain good results. Methods: This is a retrospective single center study that concludes all patients underwent chest wall reconstruction for a variety of defects resulting from resection of tumors, trauma due to primarily firearms or motor car accidents, resection of radio necrotic tissues, infection and dehiscence of median sternotomy wounds after cardiac surgery.  Results: Study population consisted of 30 patients between January 2015and may 2018, among them were 20 male (70%) and 10 female patients (30%), with a median age of 43 ± 16.3 years, resection and reconstruction was performed in 23 cases (15 neoplastic,5 infective and  3 firearm cases) while reconstruction alone was performed in 7 (traumatic flail chest)  cases. Eighteen patients, underwent rib resection with an average 4.18 ± 2.2 ribs (range 2-6). Associated lung resection was performed in 5 patients (27.8 %): diaphragmatic resection was done in 2 cases in addition total sternal resection was performed in 5 cases. Most of the patients (96.7%) had primary healing of their wounds. there was one death (3.3%) in the early postoperative period. The average length of hospital stay for all patients was 8.7 days (range: 5–15). Respiratory complications occurred in three cases in the form of atelectasis and pneumonia at the ipsilateral side of reconstruction. Three cases suffered wound seroma which successfully managed by daily dressing and antibiotic coverage. Conclusions: according to our study and the analysis of similar studies, adequate perioperative preparation of patient undergoing chest wall resection and reconstruction with adherence to effective surgical techniques allowed us to use the available materials at our center for chest wall reconstruction with good and effective results without adding burden in terms of cost on the patient

    Microstructure and Mechanical Properties of Ti-Mo-Zr-Cr Biomedical Alloys by Powder Metallurgy

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    [EN] Titanium and its alloys have been widely used as biometals due to their excellent biocompatibility, corrosion resistance and moderate mechanical properties. Ti-15Mo-6Zr-based alloys and a series of Ti-15Mo-6Zr-xCr (x = 1, 2, 3, 4 wt.%) alloys were designed and fabricated by powder metallurgy for the first time to develop novel biomedical materials. The microstructure, internal porosity and mechanical properties of the sintered Ti-15Mo-6Zr and Ti-15Mo-6Zr-xCr alloys were investigated using scanning electronic microscopy (SEM) and bending and compression tests. The experimental results indicated that the microstructure and mechanical properties of these alloys changed as different Cr levels were added. The addition of small Cr levels further increased the β-phase stability, improving the properties of the Ti-15Mo-6Zr-xCr alloy. However, all of the alloys had good ductility, and the Ti-15Mo-6Zr-2Cr alloy had lower bending and compression moduli (31 and 23 GPa, respectively) than the Ti-15Mo-6Zr-based alloys (40 and 36 GPa, respectively). Moreover, the Ti-15Mo-6Zr-2Cr alloys exhibited higher bending and compression strength/modulus ratios, which were as large as 48.4 and 52.2, respectively; these were higher than those of the Ti-15Mo-6Zr-based alloy (41.3 and 33.6, respectively). In the search for a better implant material, β phase Ti-15Mo-6Zr-2Cr, with its low modulus, ductile properties and reasonably high strength, is a promising candidate.The authors thank the Ministry of Economy and Competitiveness for financially supporting the research project MAT2014-53764-C3-1-R and the European Commission through the Erasmus Mundus scholarship program WELCOME. The European Commission via FEDER funds allowed for the purchase of equipment for research and Microscopy Service of the Polytechnic University of Valencia.Elshalakany, AB.; Ali, S.; Amigó Mata, A.; Eessaa, AK.; Mohan, P.; Osman, T.; Amigó, V. (2017). Microstructure and Mechanical Properties of Ti-Mo-Zr-Cr Biomedical Alloys by Powder Metallurgy. Journal of Materials Engineering and Performance. 26(3):1262-1271. doi:10.1007/s11665-017-2531-zS12621271263M. Geetha, A.K. Singh, R. Asokamani, and A.K. Gogia, Ti Based Biomaterials, the Ultimate Choice for Orthopaedic Implants—A Review, Prog. Mater Sci., 2009, 54, p 397–425M. Ahmed, D.G. Savvakin, O.M. Ivasishin, and E.V. Pereloma, The Effect of Ageing on Microstructure and Mechanical Properties of Powder Ti-5Al-5Mo-5V-1Cr-1Fe Alloy, Mater. Sci. Eng., 2014, A605, p 89–97M. Niinomi, Mechanical Biocompatibilities of Titanium Alloys for Biomedical Applications, J. Mech. Behav. Biomed. Mater., 2008, 1(30–4), p 2M.P. Licausi, A. IgualMun, and V.A. Borrás, Influence of the Fabrication Process and Fluoride Content on the Tribocorrosion Behaviour of Ti6Al4V Biomedical Alloy in Artificial Saliva, J. Mech. Behav. Biomed. Mater., 2013, 20(2013), p 137–148I. Cvijovic-Alagic, N. Gubeljak, M. Rakin, Z. Cvijovic, and K. Geric, Microstructural Morphology Effects on Fracture Resistance and Crack Tip Strain Distribution in Ti-6Al-4V Alloy for Orthopedic Implants, Mater. Des., 2014, 53, p 870–880Y.C. Chen, J.H. Chern Lin, and C.P. Ju, Effects of Post-aging Cooling Condition on Structure and Tensile Properties of Aged Ti-7.5Mo Alloy, Mater. Des., 2014, 54, p 515–519E.P. Lautenschlager and P. Monaghan, Titanium and Titanium Alloys as Dental Materials, Int. Dent. J., 1993, 43, p 245–253M. Long and H.J. Rack, Titanium Alloys in Total Joint Replacement—A Materials Science Perspective, Biomaterials, 1998, 19, p 1621–1639M. Long and H.J. Rack, Titanium Alloys in Total Joint Replacement a Materials Science Perspective, Biomaterials, 1998, 19, p 1621–1639M. Niinomi, Mechanical Properties of Biomedical Titanium Alloys, Mater. Sci. Eng., A, 1998, 243, p 231–236E. Cheal, M. Spector, and W. Hayes, Role of Loads and Prosthesis Material Properties on the Mechanics of the Proximal Femur After Total Hip Arthroplasty, J. Orthop. Res., 1992, 10, p 405–422J. Fan, M. Lu, H. Cheng, J. Tian, and B. Huang, Effect of Alloying Elements Ti, Zr on the Property and Microstructure of Molybdenum, Int. J. Refract. Met. Hard Mater., 2009, 27, p 78–82W.F. Ho, S.C. Wu, S.K. Hsu, Y.C. Li, and H.C. Hsu, Effects of Molybdenum Content on the Structure and Mechanical Properties of as-Cast Ti-10Zr-Based Alloys for Biomedical Applications, Mater. Sci. Eng., C, 2012, 32, p 517–522W.F.A. Ho, Comparison of Tensile Properties and Corrosion Behavior of Cast Ti-7.5Mo with c.p. Ti, Ti-15Mo and Ti-6Al-4V Alloys, J. Alloys Compd., 2008, 464, p 580–583Y.L. Zhou and D.M. Luo, Corrosion Behavior of Ti-Mo Alloys Cold Rolled and Heat Treated, J. Alloys Compd., 2011, 509, p 6267–6272N.T.C. Oliveira and A.C. Guastaldi, Electrochemical Stability and Corrosion Resistance of Ti-Mo Alloys for Biomedical Applications, Acta Biomater., 2009, 5, p 339–405Y. Chen, L. Xu, Z. Liu, F. Kong, and Z. Chen, Microstructures and Properties of Titanium Alloys Ti-Mo for Dental Use, Trans. Nonferrous Met. Soc. China, 2006, 16, p 824–828W.-F. Ho, S.-C. Wu, H.-W. Wanga, and H.-C. Hsu, Effects of Cr Addition on Grindability of Cast Ti-10Zr Based Alloys, Mater. Chem. Phys., 2010, 121, p 465–471M.J. Donachie, Titanium: A Technical Guide, 2nd ed., ASM International, Metals Park, 2000R.G. Craig, Restorative Dental Materials, 9th ed., CV Mosby, St. Louis, 1993H.C. Hsu, S.C. Wu, S.K. Hsu, T.F. Lin, and W.F. Ho, Structure and Mechanical Properties Of as-Cast Ti-5Nb-xCr Alloys, Mater. Des., 2013, 51, p 268–273H.-C. Hsu, S.-C. Wu, S.-K. Hsu, C.-T. Li, and W.-F. Ho, Effects of Chromium Addition on Structure and Mechanical Properties of Ti-5Mo Alloy, Mater. Des., 2015, 65, p 700–706J. Syarif, T.N. Rohmannudin, M.Z. Omar, Z. Sajuri, and S. Harjanto, Stability of the Beta Phase in Ti-Mo-Cr Alloy Fabricated by Powder Metallurgy, J. Min. Metall. Sect. B Metall., 2013, 49(3), p 285–292J. Syarif, E. Kurniawan, M.R. Rasani, Z. Sajuri, M.Z. Omar, and S. Harjanto, Influence of Oxygen on Microstructures of Ti-Mo-Cr Alloy, Adv. Mater. Res., 2014, 896, p 613–616E. Delvat, D.M. Gordin, T. Gloriant, J.L. Duval, and M.D. Nagel, Microstructure, Mechanical Properties and Cytocompatibility of Stable Beta Ti-Mo-Ta Sintered Alloys, J. Mech. Behav. Biomed. Mater., 2008, 1, p 345–351P. Wang, Y. Feng, F. Liu, and L.S. Guan, Microstructure and Mechanical Properties of Ti-Zr-Cr Biomedical Alloys, Mater. Sci. Eng., C, 2015, 51, p 148–152W.-F. Ho, S.-C. Wu, H.-H. Chang, and H.-C. Hsu, Structure and Mechanical Properties of Ti-5Cr Based Alloy with Mo Addition, Mater. Sci. Eng., C, 2010, 30, p 904–90

    On beta-time fractional biological population model with abundant solitary wave structures

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    Abstract The ongoing study deals with various forms of solutions for the biological population model with a novel beta-time derivative operators. This model is very conducive to explain the enlargement of viruses, parasites and diseases. This configuration of the aforesaid classical scheme is scouted for its new solutions especially in soliton shape via two of the well known analytical strategies, namely: the extended Sinh-Gordon equation expansion method (EShGEEM) and the Expa function method. These soliton solutions suggest that these methods have widened the scope for generating solitary waves and other solutions of fractional differential equations. Different types of soliton solutions will be gained such as dark, bright and singular solitons solutions with certain conditions. Furthermore, the obtained results can also be used in describing the biological population model in some better way. The numerical solution for the model is obtained using the finite difference method. The numerical simulations of some selected results are also given through their physical explanations. To the best of our knowledge, No previous literature discussed this model through the application of the EShGEEM and the Expa function method and supported their new obtained results by numerical analysis

    Modelling and control of standing up and sitting down manoeuver

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    Exoskeleton Robot is one of the most significant examples of human-oriented robotic devices. Nevertheless, the main challenge remains the complexity of their mechanical design and human-robot interfaces. This paper is an outcome of a research to model and to simulate the support of mobility of an elderly people using exoskeleton. Exoskeleton is developed in order to complement the corporal deficiencies of an elderly person in standing up and sitting down. When the natural joint torques is integrated with the exoskeleton's torque the result is in an overall torque that is comparable to that of a physically normal person. This work focuses on standing-up and sitting-down movements. Appropriate simulation models are formulated and their performances examined against measured data. The results with PID control show that at different speed of standing up and sitting down, the joint torques can be compromised. This is done within allowable limits

    Site adaptations of Acanthogyrus (Acanthosentis) tilapiae: Observations through light and scanning electron microscopy

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    Acanthogyrus (Acanthosentis) tilapiae parasites were collected from the intestines of 300 fish belonging to three tilapia species sourced at the River Nile, Giza, Egypt. The proboscis of the parasite was characterized by three rows of hooks that curved towards the posterior of the body. The first row is supported by unmodified hooks. The parasite tegument has a series of alternative folds and a large number of pores. Sensory ganglia are located on the surface of the proboscis and body. Acanthogyrus (Acanthosentis) tilapiae provokes an aggressive host response indicated by hyperplasia of the intestinal goblet cells and focal eosinophil infiltrations. This acanthocephalan parasite shows a highly modified adaptation to its site of host infection

    Molecular detection of Epstein-Barr virus among Sudanese patients diagnosed with Hashimoto’s thyroiditis

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    Objectives: Hashimoto’s thyroiditis (HT) is the most common cause of hypothyroidism. The exact mechanism initiating the development of HT is not yet clear. This study aimed to investigate the correlation between HT and the presence of Epstein-Barr virus (EBV) in a Sudanese population. Results: EBV-LMP1 was detected in 11.1% of HT cases, which is consistent with previous studies. Studies have reported a wide range of frequencies indicating the presence of EBV in HT, and patients with autoimmune thyroiditis have increased titers of anti-EBV antibodies in their sera compared to healthy subjects. Intrathyroidal EBV-infected B cells may be responsible for the increased risk of development of B-cell lymphoma in the thyroid gland in patients with autoimmune thyroiditis. Our study suggests that regular follow-up is necessary for patients diagnosed with HT and are positive for EBV, as antiviral therapy is not applicable due to the risk of thyroid dysfunction. The study suggests an association between EBV and HT, but causation cannot be determined. The study also highlights the need for further research to determine the viral role and correlate it with the severity and progression of HT.</p

    Molecular detection of Epstein-Barr virus among Sudanese patients diagnosed with Hashimoto’s thyroiditis

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    Objectives: Hashimoto’s thyroiditis (HT) is the most common cause of hypothyroidism. The exact mechanism initiating the development of HT is not yet clear. This study aimed to investigate the correlation between HT and the presence of Epstein-Barr virus (EBV) in a Sudanese population. Results: EBV-LMP1 was detected in 11.1% of HT cases, which is consistent with previous studies. Studies have reported a wide range of frequencies indicating the presence of EBV in HT, and patients with autoimmune thyroiditis have increased titers of anti-EBV antibodies in their sera compared to healthy subjects. Intrathyroidal EBV-infected B cells may be responsible for the increased risk of development of B-cell lymphoma in the thyroid gland in patients with autoimmune thyroiditis. Our study suggests that regular follow-up is necessary for patients diagnosed with HT and are positive for EBV, as antiviral therapy is not applicable due to the risk of thyroid dysfunction. The study suggests an association between EBV and HT, but causation cannot be determined. The study also highlights the need for further research to determine the viral role and correlate it with the severity and progression of HT.</p

    Adverse pregnancy outcomes in sickle cell trait: a prospective cohort study evaluating clinical and haematological parameters in postpartum mothers and newborns

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    Background: Sickle cell trait (SCT) is a congenital condition caused by the inheritance of a single allele of the abnormal haemoglobin beta gene, HbS. Carriers of SCT are generally asymptomatic, and they do not manifest the clinical and haematological abnormalities of sickle cell anaemia (SCA). However, there is evidence that they display some symptoms in stressful situations. Pregnancy is a stressful physiological event, and it is not clear if SCT adversely affects pregnancy outcomes, particularly in those from developing countries where people regularly suffer from nutritional insufficiency. Objective: This study aims to investigate pregnancy outcomes in Sudanese women with SCT. Subjects and methods: Pregnant women with (HbAS, n=34) and without (HbAA, n=60) SCT were recruited during their first trimester at El Obeid Hospital, Kordofan, Western Sudan. Following appropriate ethical approval and informed consent from the participants, detailed anthropometric, clinical, haematological, obstetric, and birth outcome data were registered. In addition, blood samples were collected at enrolment and at delivery. Results: At enrolment in the first trimester, the SCT group did not manifest SCA symptoms, and there was no difference in the haematological parameters between the SCT and control groups. However, at delivery, the women with SCT, compared with the control group, had lower levels of hemoglobin (Hb, p=0.000), packed cell volume (PCV, p=0.000), mean corpuscular haemoglobin (MCH, p=0.002) and neutrophil counts (p=0.045) and higher mean corpuscular volume (MCV, p=0.000) and platelet counts (p=0.000). Similarly, at delivery, the babies of SCT women had lower birth weight (p=0.000), lower Hb (p=0.045), PCV (p=0.000), MCH (p=0.000), and higher neutrophil (p=0.004) and platelet counts (p=0.000) than the babies of the healthy control group. Additionally, there were more miscarriages, stillbirths, and admissions to the Special Care Baby Unit (SCBU) in the SCT group. Conclusions: The study revealed that SCT is associated with adverse pregnancy outcomes, including maternal and neonatal anaemia, low birth weight, and increased risk of stillbirth, miscarriage, and admission to SCBU. Therefore, pregnant women with SCT should be given appropriate pre-conceptual advice and multidisciplinary antenatal and postnatal care
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