MCBÜ Açıkerişim Sistemi :: Browsing by Author "Aslan A."

Browsing by Author "Aslan A."

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Potentiometric titration of some dicarboxylic acids in non-aqueous media
(1997) Aslan A.; Erdoǧan Y.; Demirbaš A.; Karslioǧlu S.
Five dicarboxylic acids; adipic acid, azelaic acid, suberic acid, dodecandioic acid and tetradecandioic acid were titrated potentiometrically with tetrabutylammonium hydroxide in five different non-aqueous solvents; tert-butyl alcohol, isopropyl alcohol, acetone, pyridine and N,N-dimethylformamide. The pKa values of the compounds were determined in the solvents mentioned above.
Effects of ground hazelnut shell, wood, and tea waste on the mechanical properties of cement
(Elsevier Ltd, 1998) Demirbaş A.; Aslan A.
In this study, the mechanical properties of Portland cement mixes with an admixture such as ground hazel nut shell, spruce and beech woods, and tea waste were studied. The compressive and bending strengths test results obtainned from these mixes were investigated with comparing to the control mix. From results, it was obtained that especially ground hazelnut shell and beech wood can be used as additives or partial replacement for Portland cement. © 1998 Elsevier Science Ltd.
Evaluation of lignite combustion residues as cement additives
(Elsevier Science Ltd, 1999) Demirbaş A.; Aslan A.
In this study the physical and chemical properties of lignite fly ashes obtained from electrostatic precipitator and cyclone, lignite bottom ash, cement+lignite ash mixtures, and their effects on mechanical properties of concrete were investigated. The ashes were classified into two general types based on total silica, alumina, and iron-III oxide: class A and class B. When 25% of the cement was replaced by class A lignite bottom ash (the combined three oxide contents were 30.2%), the 28-day compressive strength increased by 18.9% compared to the control mix, and when 25% of the cement was replaced by class B lignite ash (the combined three oxide contents were 78.1%), the compressive strength decreased by 3.5% compared to the control mix. The results obtained were compared with the Turkish Standards and, in general, were found to be within the limits. As a result, the lignite fly ash and bottom ash samples may be used as cementitious materials.
A radiologico-anatomical comparative study of the cochlear aqueduct
(W.B. Saunders Ltd, 2000) Tekdemir I.; Aslan A.; Ersoy M.; Karahan S.T.; Tellioglu C.
Aim: A comparative radiologico-anatomical study of the cochlear aqueduct (CA) was performed. Materials and Methods: Eight cadavers and 23 dry temporal bones were studied. High-resolution computed tomography (HRCT) was carried out on each cadaver before microdissection. Microdissection was carried out in a plane parallel to the HRCT sections. Results: The CA was found to be located an average of 7 mm inferior to the internal acoustic meatus and at the superior edge of the jugular foramen. The external aperture of the CA was triangular in shape in 18 bones (78.3%). The petrosal fossa was located just inferior to the external aperture and housed the glossopharyngeal nerve, which had an incomplete bony canal in four bones (17.4%) and a complete bony canal in three bones (13%). It was possible to demonstrate the petrosal portion of the CA on both coronal and axial HRCT. The otic capsule segment of the CA was impossible to demonstrate on coronal sections. Conclusion: The CA cannot be visualized in only one section of the plane in HRCT. Both the otic capsule and petrosal segments can be demonstrated on axial HRCT. © 2000 The Royal College of Radiologists.
Comprehensive microsurgical anatomy of the jugular foramen and review of terminology
(Churchill Livingstone, 2001) Tekdemir I.; Tuccar E.; Aslan A.; Elhan A.; Ersoy M.; Deda H.
The microsurgical anatomy of the jugular foramen was studied in 12 formalin preserved cadavers (24 foramina) and 40 dry-skulls (80 foramina). The jugular foramen was exposed by microsurgical dissection with drilling from a superior to inferior direction. Observations regarding dural architecture of the jugular foramen and relationships between neurovascular structures passing through the foramen were noted in cadavers. Normal bony construction of the foramen and its variational anatomy were examined in dry-skull specimens. Using photographs and drawings, the anatomy of the jugular foramen is presented and related terminology is discussed in the light of a literature review. © 2001 Harcourt Publishers Ltd.
Efficacy of collar treatment for patients with cervical spondylatrosis complaining of vertigo
(Society of Physical Therapy Science (Rigaku Ryoho Kagakugakkai), 2001) Unlu Z.; Cerrahoglu L.; Aslan A.; Tarhan S.
Objective: Efficacy of collar treatment on clinical symptoms and vertebral blood flow was examined in 23 patients with cervical spondylartrosis complaining of vertigo. Methods: In pretreatment and posttreatment periods, the following parameters were studied: 1) frequency of cervicocephalic symptoms, 2) influence of severity of the vertigo on daily life activity, 3) range of active cervical joint movement, 4) pain in cervical palpation, 5) vertebral blood flow by Doppler ultrasonography, and audiologic and brainstem auditory evoked potential (BAEP) examinations for hearing. Results: Following 1 month of collar treatment, vertigo and amnesia were the only symptoms which were significantly relieved (p=0.01, p=0.03). In addition, the severity of the symptoms were noticeably decreased. Range of cervical joint movements on extention, lateral flexion and rotation were increased. Cervical palpation was reduced and the pain was less. However, no change was observed in vertebral blood flow, audiometric and BAEP examinations. Conclusion: It was concluded that vertigo in cervical spondylartrosis was not a consequence of vertebrobasillar insufficiency. Hypertonicity in cervical muscles was the primary reason for vertigo in these patients.
Morphometric analysis of anatomical relationships of the facial nerve for mastoid surgery
(2001) Aslan A.; Goktan C.; Okumus M.; Tarhan S.; Unlu H.
Surgical anatomical relationships of the facial nerve (FN) with several landmarks used in mastoid surgery were studied in temporal bone axial high resolution CT scans of 90 patients (180 ears). The shortest distances between the FN and external auditory canal (EAC), sigmoid sinus (SS), posterior fossa dural plate (PFD), and joint of the bony EAC with the lateral surface of the mastoid (M) were measured. These measurements were also analysed in respect of pneumatization and side differences. On average, it was found that FN-EAC was 2.9 mm, FN-SS was 10.5 mm, FN-PFD was 7.3 mm and FN-M was 15.3 mm. FN-EAC was found to be longer in poorly pneumatized bones whereas other distances were longer in pneumatized bones. FN-M was found to be longer on the right side.
Injury to the lacrimal apparatus after endoscopic sinus surgery: Surgical implications from active transport dacryocystography
(Mosby Inc., 2001) Unlu H.H.; Goktan C.; Aslan A.; Tarhan S.
In order to evaluate the lacrimal drainage system injury after functional endoscopic sinus surgery, surgical records and postoperative active transport dacryocystography imaging of 31 patients were analyzed. Presence of the lacrimal bone dehiscence and no passage of the contrast material into the inferior meatus were noted as the signs of injury to the lacrimal canal on active transport dacryocystography. Bony dehiscence was detected in 53.2% of the operated sides but 20% of the nonoperated sides. No passage of the contrast material into the inferior meatus was observed in 14.9% of the operated sides. There were no cases of epiphora postoperatively. The lacrimal drainage system injury was more frequently observed on the left sides operated. We conclude that lacrimal drainage system injury might occur in various extents during functional endoscopic sinus surgery. However, it does not necessarily result in postoperative epiphora. Performing the middle meatal antrostomy in posteroinferior direction, and uncinectomy with backbiting forceps or a shaver might help in reducing the lacrimal injury. Active transport dacryocystography can be adopted as an alternative diagnostic tool in detection of the lacrimal injury.
Comparison of surgical outcomes in primary endoscopic dacryocystorhinostomy with and without silicone intubation
(2002) Unlu H.H.; Toprak B.; Aslan A.; Guler C.
The surgical outcome of endoscopic endonasal dacryocystorhinostomy was analyzed in 30 cases of postsaccal stenosis. Intubation with silicone tubing was used in 14 cases (46.7%) and not used in 16 cases (53.3%). Surgical success was evaluated subjectively and objectively. The patients' complaints were improved in 85.7% of cases in the intubation group, and in 81.3% of the group in which no stent was used. Postoperative endoscopic examinations revealed that the rhinostomy opening was visible in 11 cases without intubation (68.8%) and 9 cases with intubation (64.3%). Six patients in the intubation group (42.9%) had granulation tissue at the rhinostomy site. Four patients (28.6%) had complaints regarding the intubation. Considering the similar surgical success rates, and the granulation formation, patient discomfort, and cost related to intubation, we recommend endoscopic dacryocystorhinostomy without intubation as the treatment of choice in cases of chronic epiphora due to postsaccal stenosis of the lacrimal canal.
The intracranial complication of acute isolated sphenoid sinusitis
(2002) Unlu H.Halis; Aslan A.; Goktan C.; Egrilmez M.
Acute isolated sphenoid sinusitis is a rare, potentially destructive entity, which has indistinct clinical findings and non-specific symptoms. Hence, it can be easily be misdiagnosed. We present and discuss a case of an isolated sphenoiditis with intracranial complication. © 2002 Elsevier Science Ireland Ltd. All rights reserved.
Serologic examinations of hepatitis, cytomegalovirus, and rubella in patients with Bell's palsy
(2003) Unlu Z.; Aslan A.; Ozbakkaloglu B.; Tunger O.; Surucuoglu S.
Objective: The aim of this retrospective case review was to investigate serologic evidence of cytomegalovirus, rubella virus, and hepatitis A, B, and C viruses in patients with Bell's palsy. Design: A total of 24 patients with idiopathic facial paralysis, without a history of trauma, any evidence of a tumor on high-resolution computed tomographic imaging, or any otologic disease, and 33 healthy individuals as a control group were included in this study. Facial paralysis of the patient was evaluated with the House-Brackmann grading scale. Specific immunoglobulin G and M titers were determined for cytomegalovirus, rubella, hepatitis A, hepatitis B, and hepatitis C by enzyme-linked immunosorbent assay. Results: Serologic positivity for hepatitis B was found in 15 of 21 Bell's palsy patients, compared with 32.1% in the control group. The difference was statistically significant. There was no difference in the prevalence of serologic positivity for cytomegalovirus, hepatitis A, and rubella between the patient and control groups. In one Bell's palsy patient, serologic evidence of recent cytomegalovirus infection was indicated by changes in antibody titers between samples taken on presentation and on the 16th day. There was no serologic evidence of hepatitis C in either Bell's palsy patients or the control group. Conclusion: There seems to be an association between hepatitis B and idiopathic facial paralysis. In addition, cytomegalovirus might contribute to the development of Bell's palsy in some ceases with Bell's palsy. Further studies are required to confirm these data.
Surgical implications of anatomical landmarks on the lateral surface of the mastoid bone
(Springer Paris, 2004) Aslan A.; Mutlu C.; Celik O.; Govsa F.; Ozgur T.; Egrilmez M.
The aim of this study was to examine the relationships of the surgical landmarks on the lateral surface of the mastoid bone with the landmarks in a deeper location. Simple mastoidectomy was carried out without drilling over the linea temporalis inferior (LTI) on 20 adult temporal bones. The suprameatal spine, i.e., Henle spine (HS), variants were noted. Morphometric measurements were performed between these surgical landmarks, and their variations with pneumatization or HS types were evaluated. Three types of HS were identified: triangular, crest, absent. The HS-lateral semicircular canal distance was 15 mm on average and longer in bones with a triangular HS than a crest type HS (16.4 vs. 14.3 mm). The LTI was found to be located on average 4.7 mm inferior to the middle fossa dural plate (MFD). The LTI-MFD distance had a tendency to be longer in bones without an HS than with a crest type of HS (5.9 vs. 3.9 mm). Chorda tympani emerged from the facial nerve at the stylomastoid foramen in five specimens (25%). This anatomical organization was not correlated with the type of HS. Korner's septum (KS) was identified in nine bones (45%). It was present in eight of 16 (50%) bones with good pneumatization. No tendency for the existence of KS was found for any specific type of HS. This study confirms that the mastoid antrum is located 15 mm deep to the lateral surface of the mastoid bone. It should be expected to be longer in bones with a triangular HS. In addition, the MFD is located on average 5 mm above the LTI, which could be useful information for beginners or inexperienced surgeons. The ear surgeon should anticipate that the MFD might be longer in bones without an HS. © Springer-Verlag 2004.
Anatomic limitations of posterior exposure of the sinus tympani
(2004) Aslan A.; Guclu G.; Tekdemir I.; Elhan A.
Objective The sinus tympani is a challenging area for the otologic surgeon to access and from which to remove the disease process. Recently, a posterior approach to the sinus tympani through the mastoid was proposed as an alternative technique in cases of deep sinus tympani. Study design and setting The posterior approach was performed by dissecting the triangular bony area formed by the facial nerve, lateral semicircular canal, and posterior semicircular canal in 8 temporal bone specimens. Results The edges of the triangle on the facial nerve and lateral semicircular canal were almost constant at 5 mm. The edge on the posterior semicircular canal was about 4 mm. Conclusion It is possible to expose the sinus tympani from the posterior by careful dissection through this triangle, which has almost constant dimensions.
Hearing loss does not occur in young patients undergoing spinal anesthesia
(2004) Ok G.; Tok D.; Erbuyun K.; Aslan A.; Tekin I.
Although uncommon, hearing loss after spinal anesthesia has been described. Vestibulocochlear dysfunction after spinal anesthesia in which 22-gauge and 25-gauge Quincke needles were used was investigated to determine if needle size affected hearing. Patients with American Society of Anesthesiologists physical status I and II, aged 20 to 40 years, who were undergoing lower extremity surgery under spinal anesthesia were randomized into 2 groups. After intravenous hydration, 3 mL of 0.5% bupivacaine was administered for spinal anesthesia, which was performed with a 22-gauge Quincke needle in group I (n = 30) patients and a 25-gauge Quincke needle in group II (n = 30) patients. Before surgery and 2 days after surgery, pure-tone audiometry and tympanometry were performed. Preoperative and postoperative hearing data were obtained in the right and left ears for every frequency. Headache, nausea, and vomiting and cranial nerve III, IV, V, VI, VII, and VIII function were assessed on postoperative day 2. Demographic data were not different between the groups. No hypoacousis was noted at any frequency during the entire testing period in either group. Two patients from group I experienced postdural puncture headache on postoperative day 3, and neither had hearing loss. No patient had cranial nerve dysfunction. We were unable to induce hearing loss in young patients undergoing spinal anesthesia by injecting the anesthetic with a 22-gauge or a 25-gauge Quincke needle.
Effect of thermal energy produced by drilling on the facial nerve: Histopathologic evaluation in guinea pigs
(2005) Aslan A.; Vatansever H.S.; Aslan G.G.; Eskiizmir G.; Giray G.
The effect of thermal energy due to drilling around the facial nerve canal on the facial nerve was histopathologically evaluated in four guinea pigs. The bony canal of the facial nerve was drilled using a 3-mm diamond burr for one minute. The temperature changes on the facial nerve canal were noted before and after dissection. The temporal bones of the animals were histopathologically examined under light microscopy using haematoxylin & eosin (H&E) and solochrome cyanine staining for myelin, and immunohistochemical staining for neuronal nitric oxide synthase (nNOS). Compared to the control group, it was observed with H&E staining that there was oedema among the axonal fibres and with solochrome cyanine staining that the thickness of the myelin fibres was decreased, and that the severity and extent of nNOS activity was decreased in the axonal fibres. It was concluded that a temperature increase on the facial canal may potentially lead to inflammation of the nerve, and may also cause deterioration of nerve conduction to some extent.
Considerations of isolated destruction of the short process of the incus in a case of cholesteatoma
(2005) Aslan A.; Aslan G.G.
Cholesteatoma occurs frequently with the destruction of the ossicles. The most commonly eroded ossicle has been reported to be the incus. Many studies report destruction of the long process and body of the incus. However, isolated erosion of the short process of the incus is an unusual finding. We present such a case with a slight conductive hearing loss that remained unchanged at 2 1/2 years postoperatively. The short process of the incus may contribute to hearing up to 10-15 dB. It is also possible that it plays a role in epitympanic aeration by supplying an attachment surface to the incudal folds. © Springer-Verlag 2005.
Identification of unknown bodies by using CT images of frontal sinus
(Elsevier Ireland Ltd, 2007) Tatlisumak E.; Yilmaz Ovali G.; Aslan A.; Asirdizer M.; Zeyfeoglu Y.; Tarhan S.
The aim of the study was to define a simple system for the identification of unknown bodies by using CT images of frontal sinus and to discuss whether it was worth to add measurements to the system or not. The system was including simple features as F (presence or absence of frontal sinus), S (intersinus and intrasinus septum) and S (scalloping), and named as FSS system. Measurements selected for the study were width, height, anteroposterior length, total width of two sinuses, the distance between the highest points of the two sinuses and the distance of each sinus to its maximum lateral limit. The study was conducted retrospectively on the paranasal CT scans of 100 cases (38 male and 62 female) who had no apparent sinonasal pathology. All the features and measurements were coded according to the system defined by the authors for each case and coded formulas were compared. At least 93% of the formulas could be eliminated for a case by using FSS system. The rate of success was increased to 98% by adding measurements. Contrary to objective criteria of FSS system, measurements were prone to bias. Therefore, in practice success rate would be expected to be lower than calculated. In the study population, instead of making 100 measurements, eliminating the most of the cases with FSS system and later discriminating the rest by pattern matching was seen logical. © 2006 Elsevier Ireland Ltd. All rights reserved.
CT study on morphometry of frontal sinus
(2008) Tatlisumak E.; Ovali G.Y.; Asirdizer M.; Aslan A.; Ozyurt B.; Bayindir P.; Tarhan S.
The aim of this study was to determine the prevalence and morphological characteristics of the frontal sinus in an adult population. This study was conducted retrospectively on paranasal CT scans in the axial and coronal planes of 300 cases (123 male and 177 female). The mean age was 40.74 ± 13.34 (range 20-83). Measurements of the width, height and anteroposterior length for each sinus and total width were obtained from CT scans. Measurements were compared statistically with relation to side and sex. The cases were divided into subgroups according to age for each sex and each measurement parameter was also compared among the subgroups. All measurements tended to be larger on the left side and were significantly larger in males than females. There was a significant difference in the anteroposterior lengths of right and left sides in both males and females and height for males and width for females. In both sexes, the highest values of measurements were usually observed at the 31-40 age group and there was a tendency to decrease with aging. The larger diameters of the left frontal sinus imply that it may be more possibly violated during surgical interventions. Morphometric features differed significantly in the two sexes at different ages and comparison with previous studies presented great regional variability. The size of the frontal sinus was seen to be related to age and sex. The knowledge provided in the present study is useful for some surgical procedures and widens the anthropometric knowledge of humanity. © 2008 Wiley-Liss, Inc.
Neural control of Eustachian tube function
(2009) Songu M.; Aslan A.; Unlu H.H.; Celik O.
Objectives/Hypothesis: It has been hypothesized that middle ear pressure can be controlled by the Eustachian tube through a neuronal reflex arc in animal models. We aimed to define the role of the neuronal control mechanisms in regulating middle ear pressure in humans. Study Design: Prospective study. Methods: The study population consisted of 95 ears of 95 volunteers. The mechanoreceptors on the tympanic membrane and the baroreceptors in the middle ear, which are assumed to form the afferent plexus of the neuronal reflex arc, were blocked by topical administration of lidocaine hydrochloride, in various patient groups. The Eustachian tube functions forming the efferent plexus of the neuronal reflex arc were evaluated by manometric tests both before and after blocking the possible afferent plexus in each study group. Results: The baroreceptors established in the tympanic plexus might possibly have an effective role in this mechanism where the mechanoreceptors on the tympanic membrane seem to have a minor effect. Conclusions: Neuronal control mechanism could play an important role in regulating Eustachian tube function in humans. © 2009 The American Laryngological, Rhinological and Otological Society, Inc.
Surgical anatomy of the nasolacrimal duct on the lateral nasal wall as revealed by serial dissections
(2010) Tatlisumak E.; Aslan A.; Cömert A.; Ozlugedik S.; Acar H.I.; Tekdemir I.
The anatomy of the nasolacrimal duct (NLD) in relation with the lateral nasal wall was studied in 15 half-heads of human adult cadavers by serial photographs of the dissection of the lateral nasal wall. The aim of the study was to determine the intranasal anatomical relationships of the NLD with the lateral nasal wall for surgical reference during endoscopic dacryocystorhinostomy. Following removal of the nasal mucosa anterior to the uncinate process, the exposed bone was removed by drilling. The entire NLD was exposed intranasally. The relationships of the NLD with the maxillary sinus ostium and anterior nasal spine were determined, and the length of the NLD was measured. The morphology of the NLD opening was observed, and its distance from several landmarks were measured. There were three types of intranasal orifice: pin-point, triangular and slit-like. The NLD is located, on average, 24.6 ± 3.56 mm posterior to the anterior nasal spine. The nearest distances between the opening of the NLD and the nasal floor and between the opening of the NLD and the most anterior attachment of the inferior nasal concha were 13.7 ± 3.15 and 14.3 ± 2.05 mm, respectively. The length of the NLD was 21.9 ± 2.03 mm on average. The nearest distances between the NLD and the maxillary sinus ostium was 3.9 ± 0.88 mm. Cadaver dissections and the photographs of the fine dissections provide a more accurate description of the lateral nasal wall anatomy. These data provide valuable anatomical information to the surgeon performing endonasal dacryocystorhinostomy. © 2009 Japanese Association of Anatomists.

Browsing by Author "Aslan A."

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