Ahmet Unal

Tensile Characteristics of Costal and Septal Cartilages Used as Graft Materials

OBJECTIVES To determine the biomechanical characteristics of septal cartilage (SC) and costal cartilage (CC) taken from fresh cadavers using tensile testing and to establish CC graft material of a suitable thickness (ie, with tensile characteristics closest to those of SC). METHODS Grafts of varying thickness were harvested from the central part of the seventh-rib CC and SC of 18 fresh cadavers. Tensile testing was performed with a 0.5-kilonewton load calibrated at 7 mm/min. The results were shown as a force-elongation curve. RESULTS No significant difference according to tensile force was observed between the SC group and the 1.0-mm and 1.5-mm CC groups (P = .09 and P = .32, respectively). However, a significant difference was observed between the SC group and the 2.0-mm CC group (P = .04). Although the strength value of the CC group was 5.03 MPa, the modulus of elasticity was 1.33 MPa. In the SC group, the strength value was 12.42, but the modulus of elasticity was 1.39 MPa. The strength value of the SC group was higher than that of the CC group (P = .001), but the modulus of elasticity value of the CC group was higher than that of the SC group (P = .001). CONCLUSIONS From the standpoint of tensile testing for preparing columellar struts, 1.0-mm and 1.5-mm CC have similar characteristics to SC and thus can be used instead of it. However, it is important to determine the thickness of CC by considering the expected characteristics of the established material and the forces that affect the area in the nose where the graft will be placed.

Determining the Most Suitable Costal Cartilage Level for Rhinoplasty An Experimental Study

Objective. The aim of this study was to compare the biomechanical properties of septal cartilage (SC) and costal cartilage (CC) grafts harvested from different ribs and to find at which level CC has characteristics closest to SC. Study Design. Experimental cadaver study. Setting. Istanbul Training and Research Hospital. Material and Method. Cartilage grafts were harvested from the 6th, 7th, and 8th ribs and the SC of 10 fresh cadavers. Shaped cartilage grafts were subjected to a bending test. Results were measured, and the force-deflection curve was plotted. Flexural strength (σf) and flexural modulus of elasticity (Ef) were determined. Fractured surfaces were evaluated by scanning electron microscopy (SEM). Results. According to Fmax, it was determined that ribs 6, 7, and 8 have significantly more durability compared with the SC (Ps = .030, .004, and .001). With regard to deflection, there was no significant difference between the SC and the 6th and 7th ribs and between the 6th and 7th ribs (Ps = 1.000, .088, and .306), while a significant difference was found between the SC and the 8th rib (P = .001). According to σf, no differences were seen between the 6th and 7th rib (P = .782), while difference was detected between the 6th and 8th and the 7th and 8th ribs (p = .001). Similar trends were established in Ef values as in σf. These results were confirmed by SEM images. Conclusion. The 7th CC can be used as autograft because it shows similar properties to SC. However, the 6th CC is preferred if more flexibility is desired, and the 8th CC is preferred where more strength is needed.

Mechanical properties of PE/E-glass commingled yarn wound pipes and pipe elbows

Abstract PE pipes and fittings are used in water, chemicals, as well as gas supply and distribution. In most applications, pressurized piping systems are needed. When pressure grade is increased, pipe wall thickness increases to carry the load, and the system becomes heavier and less flexible. Reinforcing the polymer could be an alternative without the need to thicken a pipe wall. It is hard to reinforce PE however, because PE does not easily adhere to fiber. In this study, the filament winding process was applied to PE pipes and elbows. PE/E-glass commingled yarn was used to make it easier to reinforce the PE. The filament winding process was modified for the commingled yarn whereby temperature and pressure were increased. Helical and circumferential winding was carried out. The thin PE film was coated. Mechanical tests and computer structural analysis were done and results were compared.

The Effects of Local and Systemic Administration of Proline on Wound Healing in Rats

ABSTRACT Purpose: Wound healing consists of a sequence of complex molecular and cellular events. Collagen is composed mainly of proline and hydroxyproline. Proline and hydroxyproline constitute 1/3 of the amino acids in collagen, which makes up approximately 30% of the proteins within the body. The hydroxylation of proline found in collagen determines the stability of the triple helical structure of collagen. In this study, we examined the effects of local and systemic administration of proline on wound healing. Materials and Methods: 24 female Sprague-Dawley rats were used in the study and divided into three groups. Group 1: The defect created in the backs of the subjects was left to secondary healing. Group 2: 200 µl proline per day was administered topically for 30 days on the defect in the backs of the subjects. Group 3: 200 µl per day was administered intraperitoneally for 30 days on the defect in the backs of the subjects. Results: On day 21, there was a statistically significant difference between the groups in terms of the mean re-epithelialization score. On days 7 and 14, there was a statistically significant difference between the groups in terms of the mean granulation score. On days 7, 14, and 21, there was a statistically significant difference between the groups in terms of the mean collagen accumulation score. On day 30, there was a statistically significant difference between Groups 1 and 3 in terms of the mean E-mode score on mechanical tensile test. Conclusion: Our study confirmed that proline has positive effects on wound healing. However, it revealed that systemic administration of proline is more effective than local administration of proline.

Tensile properties of continuous E-glass and basalt fiber reinforced polypropylene composites

Abstract Polypropylene has a higher melt viscosity and low surface tension that lead to harder interfacial bonding in composite production. However, it has some advantages like good impact strength, low water absorption, low density, low coefficient of friction and high insulating properties. In this study, E-glass fiber and basalt fiber were used to reinforce polypropylene. Powder with compatibilizer was impregnated to E-glass and basalt fiber and prepregs were produced. Then, these were embedded into polypropylene matrix and samples were obtained. Tensile properties and fiber volume ratios were determined. Also, T-peel test was applied to check bonding at the fiber-matrix interface. Fractured parts were observed and fracture types were investigated. It was concluded that both had similar bonding strength, but E-glass reinforced polypropylene composite had higher tensile properties than basalt fiber reinforced composite.

Investigation of joints between polypropylene and polybutylene terephthalate

Abstract An effective joining between polypropylene (PP) and polybutylene terephthalate (PBT) is closely related to bonding between PP and PBT. The objective of this study is to improve the bonding between PBT and PP with a compatibilizer application between joints as tie-layer at various concentrations. Flexural strength, lap-shear strength and interlaminar shear strength of joined parts were determined to determine the adhesive bonding performance. The fracture behavior of the bonds was also investigated. It was found that using compatibilizers in a PP/PBT joining system improved the mechanical characteristics. Improved results were obtained with increasing ratios of compatibilizers in tie-layer and maximum mechanical results were achieved for 100 % compatibilizer usage in PP-PBT system.

Biomechanical strength of glass ionomer cement in incudostapedial rebridging.

OBJECTIVE To study the biomechanical properties of glass ionomer cement used for incudostapedial rebridging. METHODS Two groups were established based on the size of the gap between the incus and stapes (1.0 mm in group 1 and 2.0 mm in group 2). Glass ionomer cement was applied to the gaps, and compression tests were performed. Maximum force was measured at the fracture point, and was divided by the cross-sectional area to obtain the maximum compressive strength. RESULTS No significant difference was found in the maximum force for the two groups (p = 0.312). The glass ionomer cement diameter was significantly higher in group 2 than in group 1 (p = 0.006). The maximum compressive strength was significantly higher in group 1 than in group 2 (p = 0.042). CONCLUSION The fragility of bone cement used in this study was 25.5 per cent higher for a 2 mm gap than for a 1 mm gap. We speculate that the use of bone cement may be safer for the repair of smaller incudostapedial defects.

Importance of nasal septal cartilage perichondrium for septum strength mechanics: a cadaveric study.

BACKGROUND According to the Federal Institution of Health Insurance, ENT doctors perform more skin prick tests for the diagnosis of allergic rhinitis (AR) than other medical specialties in Belgium. However, immunotherapy (IT) is not practiced by all. This study aims to obtain insight into IT practice by ENT doctors, the type of IT performed and the reasons not to perform IT. METHODOLOGY A questionnaire was sent to all registered ENT doctors of Belgium (n=648), involving questions on type and duration of ENT practice, geography and gender. In addition, the questionnaire informed about diagnosis of AR, indication for IT, type of IT performed, and reasons not to perform IT and referral pattern. RESULTS The response rate among ENT doctors was 54%, with 7% of responders being excluded as they do not diagnose AR. 81% of Belgian ENT doctors make the indication for IT in AR patients, with 19% neglecting the indication for IT in AR patients. The two main reasons for not indicating IT are lack of expertise and the perception of high costs associated with IT. 70% of ENT specialists are practicing IT themselves, with sublingual IT being mostly performed. Interestingly, IT is mostly frequently performed by those ENT doctors with long-standing ENT practice, in private practice and in Wallonia. CONCLUSION Despite the high prevalence of AR in ENT practice, IT is most frequently performed by ENT doctors with longstanding practice, working in private practice and/or in the French speaking part of Belgium. Among the different types of IT, sublingual IT is the most frequently performed means of IT by ENT doctors.OBJECTIVE To investigate the role of inflammation in non-allergic rhinitis (NAR) patients in a large series to establish the prevalence of different NAR-subtypes, clinical features and the role of nasal cytology in the diagnostic algorithm. METHODOLOGY Patients were selected out of 3650 individuals who spontaneously presented at our institution. We consecutively enrolled 519 NAR-patients in an analytical cross-sectional study between November 2007 and June 2013 (level of evidence: 3b). All patients underwent rhinological evaluation including symptoms questionnaire, endoscopy, CT scan, allergy tests and nasal cytology. RESULTS The inflammatory cell infiltrate affects the severity of symptoms differently, allowing for identification of different phenotypes of NAR. We distinguished two groups: “NAR without inflammation”(NAR-) and “NAR with inflammation”(NAR+), in addition to different NAR-subtypes with inflammation. A significant difference was observed in terms of clinical symptoms and association with comorbidities (previously diagnosed asthma and aspirin intolerance) between NAR–, NAR+ and between different NAR+ subtypes. CONCLUSION Our data suggest that NAR- and NAR with neutrophils behave similarly, showing lower symptom score values and a lower risk of association with comorbidities compared to NAR with eosinophils and mast cells (singularly or mixed). In our belief it is very important to establish the presence and type of inflammation in non-allergic rhinitis patients and nasal cytology is a very useful test in correct differential diagnosis.OBJECTIVE To assess the applicability of the Peak Nasal Inspiratory Flow (PNIF) curves in follow-up of children in the treatment of allergic rhinitis. METHODS Prospective study of 40 patients with AR, grouped in corticosteroid spray versus physiological saline solution use. Follow up for 10 weeks through clinical score and PNIF percentages in relation to the reference curves, with was-out at week 8. Statistical assessment of the effect of treatment on variation of PNIF and clinical score was calculated by ANOVA model and Multiple Comparison of Means Test - Least Significant Difference. RESULTS There was a statistically significant influence of the group, time and interaction between time and group on PNIF percentages. Throughout follow up, patients from the treatment group had mean PNIF percentages significantly higher than the placebo group. Clinical score results also demonstrated a statistically significant influence between the groups, time and interaction between time and group. CONCLUSION Increase in PNIF percentage values observed in children treated with intranasal corticosteroids revealed the applicability of PNIF curves in their follow up.OBJECTIVE This study aims to examine humans ́ abilities to localize odorants within the open field. METHODOLOGY Young participants were tested on a localization task using a relatively selective olfactory stimulus (2-phenylethyl-alcohol, PEA) and cineol, an odorant with a strong trigeminal component. Participants were blindfolded and had to localize an odorant source at 2 m distance (far-field condition) and a 0.4 m distance (near-field condition) with either two nostrils open or only one open nostril. RESULTS For the odorant with trigeminal properties, the number of correct trials did not differ when one or both nostrils were used, while more PEA localization trials were correctly completed with both rather than one nostril. In the near-field condition, correct localization was possible in 72-80% of the trials, irrespective of the odorant and the number of nostrils used. Localization accuracy, measured as spatial deviation from the olfactory source, was significantly higher in the near-field compared to the far-field condition, but independent of the odorant being localized. CONCLUSION Odorant localization within the open field is difficult, but possible. In contrast to the general view, humans seem to be able to exploit the two-nostril advantage with increasing task difficulty.BACKGROUND This study was designed to assess if illness perception, mood state and coping strategies differ according to allergic rhinitis (AR) persistence and severity. METHODS Illness perception, mood profiles, coping behaviors and rhinitis symptoms were assessed by means of validated tools inpatients classified according to the Allergic Rhinitis and Its Impact on Asthma (ARIA) guidelines. RESULTS Two hundred and thirty-one patients underwent data analysis. No difference in age, sex, socio-economic status, smoking habits was detected comparing patients according to AR severity, duration or 4 ARIA classes. Patients with intermittent AR reported higher scores than those with persistent AR in confusion-bewilderment of Profile of Mood States (POMS); patients with moderate/severe rhinitis had significantly higher scores than those with mild rhinitis in TSSS, Identity and Consequences. No differences were detected in all assessed outcomes in the 4 ARIA classes. CONCLUSIONS The patients perspective about AR is independent of persistence and severity of symptoms. This may explain why AR remains under-diagnosed and under-treated, even in its most severe forms. Self-management plans should consider the patients perspective.The assessment of Chronic Rhinosinusitis, like any other disease, may involve multiple possible disease manifestations, including subjective patient-reported outcomes, objective disease (e.g. endoscopy or radiographic), and physician-driven (e.g. need for systemic medications). Disease control is often used as a global metric of disease burden and represents the extent to which disease manifestations are within an acceptable range. Achieving control is an important treatment goal.The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 is the update of similar evidence based position papers published in 2005 and 2007 and 2012(1-3). The core objective of the EPOS2020 guideline is to provide revised, up-to-date and clear evidence-based recommendations and integrated care pathways in ARS and CRS. EPOS2020 provides an update on the literature published and studies undertaken in the eight years since the EPOS2012 position paper was published and addresses areas not extensively covered in EPOS2012 such as paediatric CRS and sinus surgery. EPOS2020 also involves new stakeholders, including pharmacists and patients, and addresses new target users who have become more involved in the management and treatment of rhinosinusitis since the publication of the last EPOS document, including pharmacists, nurses, specialised care givers and indeed patients themselves, who employ increasing self-management of their condition using over the counter treatments. The document provides suggestions for future research in this area and offers updated guidance for definitions and outcome measurements in research in different settings.BACKGROUND Endoscopic dacryocystorhinostomy (EN-DCR) is a commonly used procedure in the treatment of nasolacrimal duct obstruction (NLDO). However, there is no generally accepted disease-specific questionnaire for assessing outcomes. METHODOLOGY We conducted a prospective study to initially validate a Nasolacrimal Duct Obstruction Symptom Score questionnaire(NLDO-SS) and to evaluate the long-term success of EN-DCR procedures. Seventy-six patients (86 eyes) were evaluated in follow-up visits at 1-8 years after EN-DCR. The patients completed the NLDO-SS questionnaire twice, first, at home and, second,after receiving information from the otorhinolaryngologist, during the visit. The surgical outcome was considered successful if the irrigation succeeded and if the patient symptoms were relieved as assessed with the NLDO-SS. RESULTS The diagnostic accuracy of the NLDO-SS was 84%, sensitivity 82%, specificity 85%, positive predictive value 58%, negative predictive value 95%, odds ratio 26, risk ratio 11 and usefulness index 0.55. Cronbachs alpha was 0.85, and the test-retest reliability coefficient was 0.87. The long-term success rate after EN-DCR was 79%. CONCLUSION The NLDO-SS iss a feasible clinical tool in assessing the success of EN-DCR. The success rate was found to decrease EN-DCR at long-term follow-up.

Aramid-HDPE Composites: Influence of Interface Adhesion Measured by T-peel Test on Tensile Properties

Abstract In this study, the influence of using compatibilizer as tie-layer between fiber matrix interfaces in continuous aramid fiber reinforced high density polyethylene (HDPE) composites was investigated. Maleic anhydride (MAH) grafted polyethylene and ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer were used as compatibilizers at varying layer numbers. Adhesion strength was determined by T-peel test, and tensile test was carried out. It was found that higher MFR (Melt Flow Rate) valued matrix and compatibilizer application increased the mechanical performance. The maximum strength values were obtained with EMA-GMA applications. In observations of peeled parts and cross-sectional slices, interface adhesion was investigated and failure patterns were determined. It was seen that the samples with compatibilizer had more wetted portions especially the EMA-GMA tie-layered ones.