Publications by authors named "Hasan Uysal"

5 Publications

  • Page 1 of 1

The Small-Scale Treatment Plant Industry: Institutional Features of Companies, Problems and Functionality of Small-Scale Treatment Systems.

Environ Manage 2021 03 8;67(3):468-476. Epub 2020 Nov 8.

Zonguldak Bülent Ecevit University, Dept. of Environmental Eng, Zonguldak, Turkey.

The purposes of this study is to show the corporate characteristics of companies which have been operating in the fields of small-scale treatment plants' (SSTPs') design, construction, and installation processes, and to exhibit findings/perceptions of company employees on issues such as the initial investment and operating costs, common production and operating problems, the functionality of the small-scale treatment systems and the added value they provide to their customers' facilities. As a result of this study, it was determined that when the personnel participating in the survey were directly trained and recruited by the companies, which is generally the case, their training includes more practical methods and their experiences are shaped by the master-apprentice relationships in the sector. Regarding water treatment in SSTPs, the companies surveyed opted for traditional methods such as reverse osmosis and coagulation-flocculation, and preferred to use traditional biological treatment units-continuous flow or sequencing batch reactors (SBRs)- in wastewater treatment. In favor of businesses in need of water and wastewater management systems, the surveyed company employees have considered SSTPs as a successful, competitive advantage in the industry by maintaining low initial investment and operational costs while fulfilling the relevant environmental legal obligations. After examining the data regarding the opinions of company employees about SSTPs, it was found that there is a very significant relationship between the problems experienced during the installation/construction process and the problems during their operation.
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March 2021

Early Results of Stereotactic Radiosurgery in Uveal Melanoma and Risk Factors for Radiation Retinopathy

Turk J Ophthalmol 2020 06;50(3):156-162

Medicana International Hospital, Clinic of Radiation Oncology, Ankara, Turkey.

Objectives: To report treatment results and complications of stereotactic radiosurgery in uveal malignant melanoma and to identify risk factors for development of radiation retinopathy.

Materials And Methods: This was a retrospective study of 36 patients diagnosed with uveal melanoma between 2014 and 2019. Best corrected visual acuity, funduscopic findings, basal tumor diameter and tumor thickness were recorded at baseline and at follow-up visits at 3-month intervals. The response of tumors to stereotactic radiosurgery and complications were determined.

Results: The mean basal diameter of tumor was 10.2 (range: 4.0-19.4, standard deviation [SD]: ±3.3) mm x 9.7 (range: 4.5-18.0, SD: ±3.3), tumor thickness was 5.1 (range: 2.0-11.0, ±2.4) mm at baseline. The mean follow-up period was 17.2 (range: 6-48, SD: ±10.43) months. The mean visual acuity was 0.5 (SD: ±0.3) logMAR before treatment and 0.6 (SD: ±0.3) logMAR after the mean follow-up period. The most common complications after stereotactic radiosurgery were cataract (38.9%) and radiation retinopathy (27.7%). There was a statistically significant relation between radiation retinopathy development and tumor distance from the optic disc (p=0.04). The rate of eye salvage was 83.3% in this study.

Conclusion: Our short-term results show stereotactic radiosurgery was an effective and sustained treatment modality among the other eye conservation therapies.
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June 2020

Serum Levels of Melatonin and Sleep Evaluation Scales in the Diagnosis of Sleep Disorders in Patients with Idiopathic Parkinson's Disease.

Noro Psikiyatr Ars 2019 Dec 6;56(4):264-268. Epub 2018 Jul 6.

İzmir Tepecik Research and Training Hospital, Neurology Clinic, İzmir, Turkey.

Introduction: Sleep disturbances, such as difficulty in initiation of sleep, decrease in total sleep duration and efficacy, frequent awakenings, and increased daytime sleepiness are among the most common non-motor symptoms in patients with idiopathic Parkinson's disease (PD). However, patients usually do not consider these symptoms as important as their motor symptoms, and do not complain. We aimed to investigate PD patients for subtle sleep disturbances using sleep evaluation scales, and to evaluate the relationship between these tests and the serum levels of melatonin during night-sleep.

Methods: A total of 40 PD patients (19, female), older than 50 years, registered in our "Movement Disorders Out-patient Clinic", and 40 healthy, age and sex-matched control subjects (20, female) were included in the study. All subjects were assessed using Pittsburg Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Serum melatonin levels during night-sleep were measured in blood samples taken at 00:00 and 05:00 hours in every subject. Both groups were compared for demographical data, sleep evaluation scales and serum levels of melatonin.

Results: Patients with PD had significantly higher scores in PSQI and ESS than the healthy controls (p<0.001). Although the serum melatonin levels at two different time points during night sleep were lower in PD patients than the controls, these differences did not reach statistical significance (p=0.104 at 00:00 am, p=0.528 at 05:00 am). There was no significant correlation between the PSQI scores and serum melatonin levels in patient group (p>0.05). However, there was a significant but weak correlation (r=-0.353, p=0.025) between ESS scores and the serum melatonin levels measured at 05:00 hours in patients, but not between the melatonin levels measured at 00:00 hours.

Conclusion: Sleep evaluation questionnaires such as, PSQI and ESS, can provide useful information in PD patients with mild sleep disturbances. However, serum melatonin levels alone were not helpful in diagnosing the sleep disorders.
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December 2019

Challenges and differences in external radiation therapy for retinoblastoma: from standard techniques to new developments.

Tumori 2017 Sep 28;103(5):438-442. Epub 2015 Aug 28.

Department of Radiation Oncology, Ankara University School of Medicine, Cebeci Hospital, Ankara - Turkey.

Aims: The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife).

Methods: Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique.

Results: All techniques except electron provided similar target coverage. When comparing conformal plan with IMRT and SBRT, there was no significant difference in planning target volume dose distribution. The mean volume of ipsilateral bony orbit received more than 20 Gy, a suggested threshold for bone growth inhibition. The V20 Gy was 73% for the ET, 57% for the LFT, 87% for the CRT, 65% for the IMRT, 66% for the tomotherapy, and 2.7% for the SBRT.

Conclusions: This work supports the potential use of IMRT and SBRT to spare normal tissues in these patients.
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September 2017

Malignant peripheral nerve sheath tumor of the orbit: case report and literature review.

Skull Base 2004 May;14(2):109-13; discussion 113-4

Department of Neurosurgery, Medical Faculty, Ataturk University, Erzurum, Turkey.

A 68-year-old woman with progressive visual loss and exophthalmos in her right eye had been operated on for a mass in her right calf 3 years earlier. Imaging showed a huge mass invading the orbital structures and temporal pole. The presumptive diagnosis was a malignant orbital tumor. The tumor was resected totally and eroded tissues such as the lateral rectus muscle and dural compartments were repaired. The histological diagnosis was a malignant peripheral nerve sheath tumor (MPNST). The patient recovered uneventfully and was discharged 8 days after surgery. Two years later she died from a liver tumor. Few MPNSTs involving the orbit have been reported.
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May 2004