Camphor Sulfonic Acid Doped Poly(3-hexylthiophene) Nanofilms: Optical and Electrical Properties.

Herein, we report the fabrication and characterization of Camphor Sulfonic Acid (CSA) doped Poly(3-hexylthiophene) (P3HT) nanofilms prepared at different substrate temperature on glass by simple wire bar coating method. Spectroscopic, optic, structural and electrical properties of the prepared nanofilms were characterized by atomic force microscopy (AFM), UV-Visible spectroscopy, fluorescence spectroscopy, X-ray diffraction, NKD spectroscopy, SEM and DC electrical measurements. The detailed electrical characterizations revealed that the conductivity of the P3HT nanofilms increased when the films are doped with CSA and the conductivity increased from 5.89×10⁻5 S/cm to 1.39 × 10⁻4 S/cm for 40 °C preparation temperature. Thus, it was confirmed that the substrate temperature plays an important role on the film structure and spectroscopic properties. Additionally CSA-doping changes the optical properties, especially when the films prepared at 40 °C.

Extended endoscopic transsphenoidal approach infrachiasmatic corridor.

An extended endoscopic transsphenoidal approach is required for skull base lesions extending to the suprasellar area. Inferior approach using the infrachiasmatic corridor allows access to the lesions through the tumor growth that is favorable for the extended transsphenoidal approaches. Infrachiasmatic corridor is a safer route for the inferior approaches that is made up by basal arachnoid membrane and Liliequist's membrane with its leaves (diencephalic and mesencephalic leaf). This area extends from the optic canal and tuberculum sella to the corpus mamillare. We performed extended endoscopic approach using the infrachiasmatic corridor in 52 cases, including tuberculum sella meningiomas (n:23), craniopharyngiomas (n:16), suprasellar Rathke's cleft cyst (n:6), pituitary adenoma (n:2), fibrous dysplasia (n:1), infundibular granulosa cell tumor (n:2), and epidermoid tumor (n:2). Total resection was achieved in 17 of 23 (74%) with tuberculum sellae meningioma using infrachiasmatic approach. Twenty patients presented with visual disorders and 14 of them improved. There were two postoperative cerebrospinal fluid (CSF) leakages and one transient diabetes insipidus and one permanent diabetes insipidus. Sixteen patients were operated on by the infrachiasmatic approach for craniopharyngiomas. Improvement was reached in seven of eight patients presented with visual disorders. Complete tumor resection was performed in 10 of 16 cases and cyst aspiration in 4 cases, and there were remnants in two cases. Postoperative CSF leakage was seen in two patients. Infrachiasmatic corridor provides an easier and safer inferior route for the removal of middle midline skull base lesions in selected cases.

[Sinonasal teratocarcinosarcoma]. / Sinonazal teratokarsinosarkom.

Sinonasal teratocarcinosarcoma is an extremely rare malignant neoplasm presenting with the characteristics of a malignant teratoma and carcinosarcoma. The most common sites of origin of teratocarcinosarcomas are the nasal cavity and paranasal sinuses. The clinical presentation is usually with nasal obstruction and episodes of epistaxis. Teratocarcinosarcomas are aggressive and rapidly growing tumors with a poor prognosis. The incidence of sinonasal teratocarcinomas is higher in men than women. Treatment is primarily surgery, followed by radiotherapy. In this article, we report a 46-year-old male case of sinonasal teratocarcinosarcoma who was admitted with complaints of pain and swelling around the right eye and treated surgically followed by radiotherapy.

Endoscopic distinction between capsule and pseudocapsule of pituitary adenomas.

BACKGROUND: Pseudocapsules were first identified in pituitary adenoma surgery in 1936. Since then, the distinction between pituitary capsules and pseudocapsules has been unclear, and the definitions of these entities have varied. In this study, pituitary capsules and extracapsular dissection were examined retrospectively, intra- and extrapseudocapsular resection was evaluated, and dissection of the pituitary adenoma and pseudocapsule was examined prospectively. METHODS: Between January 2009 and May 2012, endoscopic transsphenoidal pituitary surgery was performed on 224 patients in the Department of Neurosurgery, Kocaeli University Faculty of Medicine, Turkey. Data for 174 patients were analyzed retrospectively between January 2009 and December 2011, and 50 patients treated between December 2011 and May 2012 were included in a prospective study. RESULTS: In the retrospective phase of the study, capsules were examined in 21 of the 174 patients on whom extracapsular resection had been performed. In the 50 cases treated between December 2011 and May 2012, dissection of the pituitary capsule, adenohypophysis, and pseudocapsule was performed. In 30 patients in the prospective phase of the study, pseudocapsules were identified during intraoperative endoscopic observation. Remission was achieved in 28 of 33 functioning adenomas in the prospective study. The mean follow-up period in this group was 13 months. CONCLUSION: The endoscopic and histopathological evidence provided in this study demonstrates that the pituitary capsule and pseudocapsule are distinct structures. In addition, it is also shown that extracapsular dissection can be performed in functioning adenomas that invade the suprasellar region. Significantly higher rates of total resection and higher remission rates were observed in cases where extra- and intrapseudocapsular dissection was required.

Convergence of per capita ecological footprint among BRICS-T countries: evidence from Fourier unit root test.

In recent years there has been a great deal of research into environmental pollution using a variety of techniques in response to growing environmental concerns. Convergence analysis, one of these techniques, helps determine whether the developing countries will catch up with the rich countries in pollution using unit root tests. However, the vast majority of the research in the field has generally used conventional unit root tests. Since many economic series contain structural breaks, using unit root tests that account for structural breaks is essential for accurate prediction. More specifically, if the series has a fractional process, conventional unit root tests may erroneously conclude that the departure from linearity is permanent. Moreover, the existing literature mainly uses gas emissions, such as carbon dioxide, which represent pollution weakly. Therefore, we use per capita ecological footprint (EF hereafter) as a more comprehensive pollution indicator of environmental degradation. In this direction, the study aims to determine whether BRICS-T countries' EF converges to the average of the BRICS-T for the 1992-2017 period. Besides the ADF unit root test, we employed the Fourier ADF unit root test, which considers the structural breaks, and the Fractional Frequency Fourier ADF unit root test, which accounts for structural breaks by considering fractional values. Our results showed that EF converges in Russia and Turkey according to the conventional ADF test, in China and Russia according to the Fourier ADF test, and in Brazil and China according to the Fractional Fourier Frequency test.

Extended endoscopic transphenoidal approach for tuberculum sellae meningiomas.

PURPOSE: Removal of tuberculum sella (TS) meningiomas is traditionally performed through transcranial approaches. Wide use of the endoscope in transphenoidal pituitary surgery is recently accessible through the tuberculum sellae with an endoscope-assisted or purely endoscopic technique. Extended endoscopic approach is an important and alternative route for meningiomas, which are located on the midline originating from the tuberculum sella. However, cerebrospinal fluid (CSF) leakage is an important problem in extended endoscopic approaches. In this report, we discuss surgical limitations and nuances of endoscopic transphenoidal approach from a retrospective analysis of nine patients with TS meningiomas. METHODS: Endoscopic transphenoidal approach was performed for seven women and two men (mean age, 51.1 years; age range, 32-78 years) with TS meningiomas between July 2007 and March 2010 in the Department of Neurosurgery, Kocaeli, Turkey. RESULTS: Total removal was achieved in six of nine patients. An improvement of the preoperative visual deficits was observed in six of the nine patients. Multilayer closure was performed for reconstruction, and lumbar external drainage was used for all patients for 3-5 days. CSF leakage was not seen in any of the patients after the operation and removal of the drainage. CONCLUSION: Endoscopic extended transphenoidal approach is still not a standardized procedure for TS meningiomas, but it may be considered as an alternative procedure in selected cases.

Microsurgical and endoscopic anatomy of Liliequist's membrane and the prepontine membranes: cadaveric study and clinical implications.

BACKGROUND: Liliequist's membrane is mostly described as having a diencephalic leaf, mesencephalic leaf, and diencephalic-mesencephalic leaves in the literature. Also different descriptions of the prepontine membranes were reported. In this study, we visualized the regular structural forms of membranes without disturbing any attachments and defined infrachiasmatic and prepontine safety zones. We discussed the clinical significance of these structures. MATERIALS AND METHODS: The study was carried out on 24 adult human cadavers at the Morgue Specialization Department of the Forensic Medicine Institution following the initial autopsy examination. Liliequist's membrane and the prepontine membranes were explored after retraction of the frontal lobes. Dissections were performed under the operative microscope. A 0- and 30-degree, 2.7-mm angled rigid endoscope (Aesculap, Tuttlingen, Germany) was advanced through the prepontine cistern from the natural holes of membranes, or small holes were opened without damaging the surrounding structures. RESULTS: The basal arachnoid membrane (BAM) continued as Liliequist's membrane (LM) without any distinct separation in all specimens. The LM coursed over the posterior clinoids and split into two leaves as the diencephalic leaf (DL) and mesencephalic leaf (ML) in 18 specimens; the medial pontomesencephalic membrane (MPMM) coursed anterolaterally as a continuation of the ML and attached to the medial surfaces of the fifth and sixth nerves, joining with the lateral pontomesencephalic membrane (LPMM), which was also a posterolateral continuation of the ML in all specimens. The medial pontomedullar membrane (MPMdM) and lateral pontomedullar membrane (LPMdM) were observed in 21 specimens. The MPMdM membrane was a continuation of the MPMM, and the LPMdM was a continuation of the LPMM in all 21 specimens. CONCLUSION: We observed that the LM is a borderless continuation of the BAM. The MPMM and LPMM split from the ML without any interruptions. The MPMdM and LPMdM were a single membrane continuing from the MPMM and LPMM. We determined infrachiasmatic and prepontine areas that can be important for inferior surgical approaches.

Evaluation of early visual recovery in pituitary macroadenomas after endoscopic endonasal transphenoidal surgery: Quantitative assessment with diffusion tensor imaging (DTI).

BACKGROUND: Visual field analyses reflect the degree of the compression to the optic nerve that results the structural damage of the nerve. These structural damages can be evaluated by diffusion tensor imaging (DTI), which assesses the structural integrity of white matter tracts. Thus, we evaluated the quantitative assessment of early visual recovery in patients with pituitary macroadenomas, corresponding DTI with visual field analyses. METHODS: Seventy-two patients who had pituitary macroadenomas with visual field defects were included in the study retrospectively. All patients were operated on by pure endoscopic transphenoidal approach. Visual field assessment using Humphrey field analyzer and DTI with 3T magnet were performed in the preoperative and postoperative second day and sixth month. FINDINGS: Mean symptom duration was 14.7 ± 10.5 weeks in the full recovery group patients, 50.1 ± 29.1 weeks in partial recovery patients, and 92.4 ± 15.4 weeks in the ones with no recovery. There was a significant difference at p < 0.001 among the groups. On visual field analysis, the visual lost was mostly recognized at upper temporal levels preoperatively. Visual field findings of both eyes were improved in 80% of the patients. Among these, 25% revealed full recovery, 55.6% partial recovery, and 19.4% did not demonstrate significant changes. DTI assessments of affected sides revealed preoperative fractional anisotropy (FA) values below 0.400 and mean diffusivity (MD) values over 1,400 × 10(-6) mm(2) s(-1) were related with no visual improvement in the postoperative 6 months period. The percentage increase of mean FA values of the affected areas postoperatively were found to be 21.9% in totally responded patients, 20.6% in partial responded patients, and 9.8% in patients that did not respond. CONCLUSIONS: There is a correlation between DTI-derived FA values of the optic nerves and visual parameters. DTI assessments of the affected sides with FA and MD values may help to estimate the response of visual improvement to the surgical therapy in the early postoperative period.

Microsurgical anatomy of membranous layers of the pituitary gland and the expression of extracellular matrix collagenous proteins.

BACKGROUND: There are several reports about the microanatomical and histological features of sellar and parasellar membranous structures and clinical studies about MMP proteinase as a predictive factor. However, studies on collagen contents of sellar and parasellar membranous structures are limited. We demonstrated the membranous structures surrounding the pituitary gland and defined extracellular matrix (ECM) collagenous proteins, collagen I-IV expression patterns of sellar and parasellar connective tissues. METHODS: The study was carried out on ten fresh postmortem human bodies at the Forensic Medicine Institution. Cavernous sinuses were resected with sellar structures and were stored at -80°C liquid nitrogen tanks. Medial wall of the cavernous sinus, pituitary capsule and pituitary tissue samples were obtained for RT-PCR. Opposite side specimens were used for histological and immune staining studies. Collagens I-IV were studied by immunohistochemical and reverse transcription polymerase chain reaction (RT-PCR) methods. FINDINGS: The pituitary capsule and medial wall were identified as two different structures. The fibrous membrane, as the third membrane, was identified as staying whole in eight of ten specimens. Increased type IV collagen was determined in the pituitary gland, medial wall and pituitary capsule, respectively, in both RT-PCR and immunhistochemical studies. Immunhistochemical studies revealed that collagen I was strongly expressed in both the medial wall and pituitary gland. CONCLUSION: Increased type IV collagen was detected especially in pituitary tissue, the medial wall and the pituitary capsule by immune staining and RT-PCR. Type IV collagen was considered to be an important factor in the progression of adenoma and invasion.

Immunohistochemical analysis of TIMP-2 and collagen types I and IV in experimental spinal cord ischemia-reperfusion injury in rats.

BACKGROUND: Thoracic and thoracoabdominal aortic intervention carries a significant risk of spinal cord ischemia. The pathophysiologic mechanisms that cause hypoxic/ischemic injury to the spinal cord have not been totally explained. In normal spinal cord, neurons and glial cells do not express type IV collagen. Type IV collagen produced by reactive astrocytes is reported to participate in glial scar formation. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors that regulate the activity of the matrix metalloproteinases (MMPs). TIMP-2 binds strongly with MMP-2, facilitating activation by membrane-type MMP. Imbalance between TIMPs and MMPs can lead to excessive degradation of matrix components. Type IV collagen involved in the blood-brain barrier disruption and glial scar formation, TIMP-2 influences MMP-2 that controls degradation of collagen I and IV. OBJECTIVE: To examine the immunohistochemical analysis of TIMP-2 and collagen types I-IV in experimental spinal cord ischemia-reperfusion in rats. METHODS: Thirty-two male Wistar rats weighing 250-300 g were divided into four groups: group S: sham group (n = 8); group 0P: 30-minute occlusion without perfusion (n = 8); group 3P: 30-minute occlusion and 3-hour perfusion (n = 8); and group 24P: 30-minute occlusion and 24-hour perfusion (n = 8). Infrarenal aorta was cross-clamped at two sites by using two aneurysm clips for 30 minutes. Reperfusion was provided after removal of the clips. Lumbar spinal cord segments were removed for immunohistochemical analysis. RESULTS: TIMP-2 and collagen staining in 3-hour perfused (3P) group were nearly the same with sham group (S). TIMP-2 and collagen staining increased in the 24-hour perfused group. CONCLUSION: Alterations in collagen levels may relate to the biphasic breakdown of the blood-brain barrier and collagen staining in new cell types with relation to glial scar formation. Our results demonstrate that 3-hour perfusion after occlusion in hypoxic/ischemic spinal cord injury seems to be the critical reversible period.

Extended endoscopic approaches for midline skull-base lesions.

The endoscopic transsphenoidal approach has been reported in the literature as a useful tool to treat sellar and parasellar lesions. The endoscope permits a panoramic view instead of the narrow microscopic view, and it allows the inspection and removal of the lesions of sellar, parasellar, and suprasellar compartments by angled-lens endoscopes. On the basis of the experience gained with the use of the endoscope, we have performed extended endoscopic endonasal transsphenoidal approach in 13 of 200 (total endoscopic transphenoidal approaches since September 1997) patients for the last 5 years. Extended endoscopic transsphenoidal approach was performed for three patients with pituitary adenoma, two patients with craniopharyngioma, one patient with metastatic lesion, one patient with anaplastic germinoma, two patients with chordoma, one patient with chondrosarcoma, one plasmocytoma, and two patients with tuberculum sella meningioma. Total removal of the tumor was achieved in nine patients and subtotal removal was achieved in four patients. Extended approaches are essential for reaching the area from lamina cribrosa to the cranio-cervical junction. Endoscopic approach permits reaching the lesion without brain retraction and with minimal neurovascular manipulation. The main problems are related to the hemorrhage control of intracranial vessels and to the closure of the dural and bony defects, with subsequent increased risk of postoperative cerebrospinal fluid leak, tensive pneumocephalus, and/or meningitis.

Effect of smoking on rat basilar artery: correlation with inducible nitric oxide synthase and endothelin converting enzyme-1.

AIM: Smoking is an extremely important risk factor for subarachnoid hemorrhage and seems to increase rupture risk of unruptured aneurysms by accelerating their growth rate. The aim of the study was to investigate the effect of smoking on the luminal diameter with wall thicknesses of rat basilar arteries and to detect alterations of inducible nitric oxide synthase and endothelin-converting enzyme -1 in the endothelial cells. MATERIAL AND METHODS: Rats were divided into two groups. The level of middle pons slices were embedded in paraffin before they were stained with hematoxylin and eosin. Rabbit anti-human inducible nitric oxide synthase and endothelin converting enzyme-1 antibodies were used. RESULTS: Significant decrease of the vessel luminal diameter and increase of the vessel wall thickness were found in chronic smokers in our study. There was a linear and significant (p= 0,023, r =0,704) correlation between thickness of the wall and endothelin converting enzyme-1 immune reaction. Correlation was not found with inducible nitric oxide synthase (p > 0.05). CONCLUSION: This study on the comparison of vessel luminal diameter and vessel wall thickness with inducible nitric oxide synthase and endothelin converting enzyme-1 immune reactions revealed that the main effect of smoking on the vessel wall is associated with endothelin converting enzyme-1.

Effects of gel morphology on the lysozyme adsorption and desorption kinetics of temperature sensitive magnetic gel composites.

Tuning the adsorption and desorption rate constant of proteins is a hot topic for broad range of applications in biotechnology and medical science; especially controlled drug delivery and protein separation are the prominent examples in this field. In this study, Gel-MNPs (Poly(N-isopropylacrylamid) PNIPA-Magnetic Nano Particles) composites were synthesized by using different concentrations of monomer and cross-linker to observe the effect of gel morphology on the adsorption and desorption rate constant and kinetics of lysozyme protein. The synthesized composites were characterized by XRD, VSM, SEM and FTIR techniques. The characterization results showed that superparamagnetic Fe3O4 nanoparticles were synthesized inside the temperature sensitive PNIPA hydrogels. Fluorescence measurements were performed for monitoring the adsorption and desorption of lysozyme through Gel-MNPs composites. The adsorption process obeyed pseudo first and second order kinetic models at above and below the lower critical solution temperature (LCST) of PNIPA gels. Pseudo first order kinetic indicates physisorption, between the lysozyme and composite material for both adsorption and desorption. The adsorption was effective below LCST, but it was not effective at a temperatures higher than LCST; the adsorption rate constant was found between 0.59 and 0.082 s-1 at 22 °C. On the other side, samples show well desorption ability at the temperature above than LCST; the desorption rate constant was found between 0.080 and 0.092 s-1 at 45 °C. Moreover, the effects of monomer and cross-linker concentration on the adsorption and desorption kinetics are determined and discussed at the end of the manuscript.

Biochemical effects of experimental epidural hematoma on brain parenchyma of rats.

INTRODUCTION: The management of epidural hematoma is classified into surgical or conservative treatment according to clinical and radiologic parameters. In the recent years, the number of paper suggesting conservative management has been increasing. The experimental works that have been performed are based on especially the effects of epidural hematomas. Basic pathophysiologic factors on ischemia result of brain trauma are based on biochemical mediators. Nitric oxide (NO) and malondialdehyde (MDA) are the substances that play important roles in brain damage after trauma. MATERIAL AND METHOD: In this study, 36 rats are divided into three groups (n = 12/group). Epidural hematoma was achieved by 0.1 ml autolog blood in rat epidural space with balloon model. Early and late phase biochemical effects on parenchyma of epidural hematoma operated in a volume which neither alters intracranial pressure (ICP) nor creates shift effect were observed. Biochemical changes of NO and MDA levels were examined in each of three experimental groups. RESULTS: NO values increased significantly in the early group (6 hours) compared with those in the control group. Difference of NO values between the control and late groups was not significant. An increase has been found in MDA values in the control group compared with those in the early group. MDA values of the late group (30 days) were closer to that of the control group. CONCLUSION: In this study, considering biochemical results, we have found that conservative volumes which neither increase ICP nor cause brain shift do not lead to permanent changes on brain.

Arteriovenous malformation associated with multiple aneurysms including anterior communicating artery aneurysm located in the third ventricle: a case report.

Following the significant advances in neuroradiology, it has been now recognized that an intracranial arteriovenous malformation (AVM) lesion and vascular aneurysm(s) might coexist more often than estimated before. A58-yearold female seen due to a subarachnoid hemorrhage (SAH) was subsequently shown to have an AVM lesion fed by the pericallosal frontopolar, M1 segment of the middle cerebral artery along with three cerebral aneurysms. The AVM lesion was totally excised and the coexisting aneurysms were successfully clipped. As a very rare finding, one of the aneurysms originating from the Anterior Communicating Artery was localized in the 3rd ventricle penetrating the lamina terminalis.

Familial syringomyelia in two siblings: case report.

We report on syringomyelia of the thoracic spinal cord in two sisters without a Chiari or any other malformation. In both cases syringomyelia was determined by magnetic resonance imaging (MRI). Spinal MRI showed a syringomyelia between T6-T8 levels in the first sibling and between T7- T9 in the second sibling. The cranio-cervical junction was normal and tonsiller ectopia was not present. Neurological examination of both sisters was normal. They did not undergo surgery as they had mild symptoms without neurological deficit and the size of the syrinx was small. Familial syringomyelia is a very rare finding and extremely rare at only the thoracic level. Genetic and environmental factors seem to be involved in familial syringomyelia.

Chiari 1 malformation with syringomyelia: correlation of phase-contrast cine MR imaging and outcome.

AIM: This study was designed to determine the hemodynamics of cerebrospinal fluid flow in syringomyelia patients associated with Chiari I malformation using phase-contrast velocity-encoded-cine MRI and also to find out whether treatment outcomes may be predicted by these flow measurements. MATERIAL AND METHODS: Eighteen consecutive symptomatic patients with syringomyelia associated with Chiari 1 malformation were included. The PC VEC MRI was performed at the level of foramen magnum and syrinx cavity both preoperatively and 6 months postoperatively. Following surgery, the modified Asgari score was calculated, and the association between CSF flow pattern and clinical outcome was assessed. RESULTS: Evaluation of clinical symptoms at postoperative 6th month revealed improvement in 11 (61%) patients and stabilization in 5 (28%) patients whereas results were poor in 2 (11%) patients. Preoperative cine MRI flow studies showed a heterogeneous pattern at the foramen magnum level in all of the patients. Postoperative cine MR flow studies demonstrated the change from heterogeneous pattern to sinusoidal pattern in 11 patients and a decrease in heterogeneity in 7 patients. CONCLUSION: Our results indicate that CSF flow measurements using PC VEC MRI can give important information regarding the prognosis and follow-up of the patients with Chiari I malformation.

Brucellar brain abscess and bilateral arachnoid cysts, unilaterally complicated by subdural haematoma.

Arachnoid cysts are benign developmental cysts that occur along the cerebrospinal axis. Brucellar abscesses in the brain are relatively uncommon, with only a few cases reported in the literature. We report here a patient with a brucellar brain abscess and bilateral arachnoid cysts (one complicated with subdural haemorrhage), who was successfully managed with craniotomy and antibiotics.

One pot synthesis and characterization of Fe3O4 Nanorod-PNIPA Nanogel Composite for protein adsorption.

In this study, Fe3O4 Nanorod-PNIPA Nanogel Composite nanomaterial is synthesized, characterized and used for lysozyme adsorption. XRD, ATR-FTIR, AFM and SEM measurements reveal that nanorods-nanogels composite was prepared successfully. The diameter of nanorods and the average particle size of nanogels are found around 150nm and 300nm, respectively. VSM measurement shows that the Fe3O4 particles are in rod shape and has superparamagnetic behavior, no hysteresis and remnant is detected. The adsorption kinetic of lysozyme on composite material is studied via fluorescence method, and the adsorption reaction rate constant is calculated as 0.904s(-1) by using Langmuir-Hinshelwood pseudo second order model. Fe3O4 Nanorod-PNIPA Nanogel Composite is appeared as a fast catalyst for lysozyme like protein immobilization.

Effect of UV-light on the uniaxial tensile properties and structure of uncoated and TiO2 coated Bombyx mori silk fibers.

The effect of UV-light on the uniaxial tensile properties and the structure of uncoated and TiO2 coated silk fibers in the bave form by using sol-gel method was investigated with tensile testing and FT-IR/ATR spectroscopy methods after the silk filaments were exposed to UV-light with high intensity of 760W/m(2) for different times from 0.5h to 1day. It was clearly observed that TiO2 coating considerably increased the Young's modulus of the uncoated silk single filament by around 17% before the UV-irradiation. The yield point and the post yield region disappeared on the stress-strain curves of both uncoated and TiO2 coated silk filaments after UV-irradiation time higher than 1h. Except for the Young's modulus, most of the tensile characteristics of both uncoated and TiO2 coated silk filaments decreased remarkably with increasing UV-irradiation time, e.g., after 1h irradiation, although the Young's modulus slightly changed and ultimate tensile strength decreased by only around 18% and 23%, for the uncoated and TiO2 coated silk filaments, respectively; breaking extension decreased dramatically by 67% and 72%, respectively, for uncoated and TiO2 coated silk filaments. Only the Young's modulus of TiO2 coated silk filaments which can be considered as a more stable tensile characteristic became significantly higher than that of the uncoated silk filaments with increasing UV-irradiation time. After 1day irradiation, even though the uncoated silk filaments could not be tested and completely lost of their fiber properties, the TiO2 coated silk filaments showed a stress-strain curve in initial elastic region with Young's modulus of ∼13GPa which indicates considerable protective effect of TiO2 on the silk fiber structure, especially on the ß-sheet microcrystals against UV-radiation. The FT-IR/ATR spectral results showed that significant photodegradation took place in not only crystalline but also amorphous regions which were deduced from the decrease in the absorbance ratios of the bands assigned to CH3 rocking, Cα-Cß, Cα-C stretching vibrations in ß-sheet crystalline regions as well as the Amide I, II, and III bands for both crystalline and amorphous regions. Even though the ratio of crystalline to amorphous regions in uncoated silk filaments decreased significantly, the ratio in TiO2 coated silk filaments became almost constant with increasing UV-irradiation time which may indicate more stable ß-sheet microcrystals against photodegradation.