Hedging against bunker price fluctuations by using derivative products

Sercan EROL 국제이네비해양경제학회 2017 International Journal of e-Navigation and Maritime Vol.8 No.1

Recent approaches and opinions support that shipping companies must take precautionary measures against financial risks and design steadier steps for financial management. The key to developing, implementing, and managing a successful hedging strategy is to use effective forecasting systems and appropriate financial derivative products. The key objective of this study is to control risks from bunker cost fluctuations using financial derivative products. To do so, a time-series analysis is conducted using a dataset derived from a bunker index system. The artificial neural network method is used for time-series analysis with a mean absolute percentage error of 0.9182105. Next, progress predictions of bunker costs and hedging strategies are determined to use financial derivative products against their risks. Finally, this study concludes that forward agreements can serve as the perfect protection mechanism against bunker risks in tramp shipping.

A cone-beam computed tomography evaluation of buccal bone thickness following maxillary expansion

Sercan Akyalcin,Jeffrey S. Schaefer,Jeryl D. English,Claude R. Stephens,Sam Winkelmann 대한구강악안면방사선학회 2013 Imaging Science in Dentistry Vol.43 No.2

Purpose: This study was performed to determine the buccal alveolar bone thickness following rapid maxillary expansion (RME) using cone-beam computed tomography (CBCT). Materials and Methods: Twenty-four individuals (15 females, 9 males; 13.9 years) that underwent RME therapy were included. Each patient had CBCT images available befor (T1), after (T2), and 2 to 3 years after (T3) maxillary expansion therapy. Coronal multiplanar reconstruction images were used to measure the linear transverse dimension, inclinations of teeth, and thickness of the buccal alveolar bone. One-way ANOVA analysis was used to compare the changes between the three times of imaging. Pairwise comparisons were made with the Bonferroni method. The level of significance was established at p<0.05. Results: The mean changes between the points in time yielded significant differences for both molar and premolar transverse measurements beetween T1 and T2 (p<0.05) and between T1 and T3 (p<0.05). When evaluating the effect of maillary expansion on the amount of buccal alveolar bone, a decrese between T1 and T2 and an increase between T2 and T3 were found in the buccal bone thickness of both the maxillary first premolars and maxillary first molars. However, these changes were not significant. Similar changes were observe for the angular measurements. Conclusion: RME resulted in non-significant reduction of buccal bone between T1 and T2. These changes were reversible in the long-term with no evident deleterious effects on the alveolar buccal bone.

Smile esthetics

Sercan Akyalcin,Kenner Misner,Jeryl D. English,Wick G. Alexander,J. Moody Alexander,Ron Gallerano 대한치과교정학회 2017 대한치과교정학회지 Vol.47 No.2

Objective: To analyze the long-term changes in maxillary arch widths and buccal corridor ratios in orthodontic patients treated with and without premolar extractions. Methods: The study included 53 patients who were divided into the extraction (n = 28) and nonextraction (n = 25) groups. These patients had complete orthodontic records from the pretreatment (T1), posttreatment (T2), and postretention (T3) periods. Their mean retention and postretention times were 4 years 2 months and 17 years 8 months, respectively. Dental models and smiling photographs from all three periods were digitized to compare the changes in three dental arch width measurements and three buccal corridor ratios over time between the extraction and nonextraction groups. Data were analyzed using analysis of variance tests. Post-hoc multiple comparisons were made using Bonferroni correction. Results: Soft-tissue extension during smiling increased with age in both groups. The maximum dental width to smile width ratio (MDW/SW) also showed a favorable increase with treatment in both groups (p < 0.05), and remained virtually stable at T3 (p > 0.05). According to the MDW/SW ratio, the mean difference in the buccal corridor space of the two groups was 2.4 ± 0.2% at T3. Additionally, no significant group × time interaction was found for any of the buccal corridor ratios studied. Conclusions: Premolar extractions did not negatively affect transverse maxillary arch widths and buccal corridor ratios. The long-term outcome of orthodontic treatment was comparable between the study groups.

Evaluation of the Radiation Pneumonia Development Risk in Lung Cancer Cases

Yilmaz, Sercan,Adas, Yasemin Guzle,Hicsonmez, Ayse,Andrieu, Meltem Nalca,Akyurek, Serap,Gokce, Saban Cakir Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.17

Background: Concurrent chemo-radiotherapy is the recommended standard treatment modality for patients with locally advanced lung cancer. The purpose of three-dimensional conformal radiotherapy (3DCRT) is to minimize normal tissue damage while a high dose can be delivered to the tumor. The most common dose limiting side effect of thoracic RT is radiation pneumonia (RP). In this study we evaluated the relationship between dose-volume histogram parameters and radiation pneumonitis. This study targeted prediction of the possible development of RP and evaluation of the relationship between dose-volume histogram (DVH) parameters and RP in patients undergoing 3DCRT. Materials and Methods: DVHs of 41 lung cancer patients treated with 3DCRT were evaluated with respect to the development of grade ${\geq}2$ RP by excluding gross tumor volume (GTV) and planned target volume (PTV) from total (TL) and ipsilateral (IPSI) lung volume. Results: Were admitted statistically significant for p<0.05. Conclusions: The cut-off values for V5, V13, V20, V30, V45 and the mean dose of TL-GTV; and V13, V20,V30 and the mean dose of TL-PTV were statistically significant for the development of Grade ${\geq}2$ RP. No statistically significant results related to the development of Grade ${\geq}2$ RP were observed for the ipsilateral lung and the evaluation of PTV volume. A controlled and careful evaluation of the dose-volume histograms is important to assess Grade ${\geq}2$ RP development of the lung cancer patients treated with concurrent chemo-radiotherapy. In the light of the obtained data it can be said that RP development may be avoided by the proper analysis of the dose volume histograms and the application of optimal treatment plans.

A cone-beam computed tomography evaluation of buccal bone thickness following maxillary expansion

Akyalcin, Sercan,Schaefer, Jeffrey S.,English, Jeryl D.,Stephens, Claude R.,Winkelmann, Sam Korean Academy of Oral and Maxillofacial Radiology 2013 Imaging Science in Dentistry Vol.43 No.2

Purpose: This study was performed to determine the buccal alveolar bone thickness following rapid maxillary expansion (RME) using cone-beam computed tomography (CBCT). Materials and Methods: Twenty-four individuals (15 females, 9 males; 13.9 years) that underwent RME therapy were included. Each patient had CBCT images available before (T1), after (T2), and 2 to 3 years after (T3) maxillary expansion therapy. Coronal multiplanar reconstruction images were used to measure the linear transverse dimensions, inclinations of teeth, and thickness of the buccal alveolar bone. One-way ANOVA analysis was used to compare the changes between the three times of imaging. Pairwise comparisons were made with the Bonferroni method. The level of significance was established at p<0.05. Results: The mean changes between the points in time yielded significant differences for both molar and premolar transverse measurements between T1 and T2 (p<0.05) and between T1 and T3 (p<0.05). When evaluating the effect of maxillary expansion on the amount of buccal alveolar bone, a decrease between T1 and T2 and an increase between T2 and T3 were found in the buccal bone thickness of both the maxillary first premolars and maxillary first molars. However, these changes were not significant. Similar changes were observed for the angular measurements. Conclusion: RME resulted in non-significant reduction of buccal bone between T1 and T2. These changes were reversible in the long-term with no evident deleterious effects on the alveolar buccal bone.

Compartment Syndrome Following Arthroscopic Removal of a Bullet in the Knee Joint after a Low-Velocity Gunshot Injury

Mert Keskinbora,Sercan Yalçin,İsmail Oltulu,Mehmet Emin Erdil,Tuğrul Örmeci 대한정형외과학회 2016 Clinics in Orthopedic Surgery Vol.8 No.1

Gunshot injuries are getting more frequently reported while the civilian (nongovernmental) armament increases in the world. A 42-year-old male patient presented to emergency room of Istanbul Medipol University Hospital due to a low-velocity gunshot injury. We detected one entry point on the posterior aspect of the thigh, just superior to the popliteal groove. No exit wound was detected on his physical examination. There was swelling around the knee and range of motion was limited due to pain and swelling. Neurological and vascular examinations were intact. Following the initial assessment, the vascular examination was confirmed by doppler ultrasonography of the related extremity. There were no signs of compartment syndrome in the preoperative physical examination. A bullet was detected in the knee joint on the initial X-rays. Immediately after releasing the tourniquet, swelling of the anterolateral compartment of the leg and pulse deficiency was detected on foot in the dorsalis pedis artery. Although the arthroscopic removal of intra-articular bullets following gunshot injuries seems to have low morbidity rates, it should always be considered that the articular capsule may have been ruptured and the fluids used during the operation may leak into surrounding tissues and result in compartment syndrome.

Penicillin G-induced hemorrhagic cystitis

Engin Kaya,Sercan Yilmaz 대한내과학회 2015 The Korean Journal of Internal Medicine Vol.30 No.5

To the best of our knowledge, if drug-induced hemorrhagic cystitis occurs during multidrug treatment, the best way to identify the causative drug is to discontinue the drugs one by one.

Comparison of Three Different Induction Regimens for Nasopharyngeal Cancer

Kertmen, Neyran,Aksoy, Sercan,Cengiz, Mustafa,Yazici, Gozde,Keskin, Ozge,Babacan, Taner,Sarici, Furkan,Akin, Serkan,Altundag, Kadri,Gullu, H. Ibrahim Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.1

Background: The standard treatment of local advanced nasopharyngeal cancer is chemoradiotherapy. There is a lack of data concerning induction therapy. In this study we retrospectively examined patients treated with induction therapy and chemoradiotherapy. Materials and Methods: Locally advanced nasopharyngeal cancer patients treated between 1996 and 2013 in our clinic were included in the study. Three different induction regimens were administered to our patients in different time periods. The regimen dosages were: CF regimen, cisplatin $50mg/m^2$ 1-2 days, fluorouracil $500mg/m^2$ 1-5 days; DC, docetaxel $75mg/m^2$ 1 day, cisplatin $75mg/m^2$ 1 day; and DCF, docetaxel $75mg/m^2$ 1 day, cisplatin $75mg/m^2$ 1 day, 5-Fu $750mg/m^2$ 1-5 days. Most of the patients were stage III (36.4%) and stage IV (51.7%). Results: Median follow-up time was 50 months (2-201 months). Three-year progression-free survival (PFS) was 79.3%, and 5-year PFS 72.4% in all patients. Three-year overall survival (OS) was 87.4% and 5-year OS 76% in all patients. In terms of induction therapies, 3-year OS was 96.5% in the DCF group, 86.6% in the DC group and 76.3% in the CF group (p=0.03). Conclusions: There was no significant differences in response rate and PFS between the three regimens. OS in the DCF group was significantly higher than in the other groups. However, this study was retrospective and limited toxicity data were available; the findings therefore need to be interpreted with care.

Laser-Activated Organic Bleaching Process as an Environmentally Friendly Clean Alternative to Permanganate Bleaching in Denim Washing

Rıza Atav,Öner Gündüz,Sercan Yaz,Gizem Çakan,Bahadırhan Sevgili 한국섬유공학회 2023 Fibers and polymers Vol.24 No.8

Today, sustainable production has become an important concept. As the trends in the world bring about the widespread use of used-looking clothes, it has become mandatory to apply processes such as spray rodeo, which is the process done by spraying permanganate with a special spray gun or applying it with a brush to the desired area. However, permanganate has risk of causing irritation to the face and eyes, and cough, mucosal irritations, shortness of breath, etc. Therefore, it is of great importance to replace permanganate with clean alternatives. In this study, it was aimed to obtain high bleaching efficiency via laser-activated organic bleaching process and thus to obtain permanganate-like results in a sustainable way. It was found that the effects of organic bleaching agent concentration and pixel time on the degree of color fading are statistically significant and the optimum color fading could be achieved at 30% bleaching agent concentration and 300 μs pixel time. However, the bleaching agent concentration and/or pixel time can be changed according to the desired degree of color fading. Results indicated that by using laser-activated organic bleaching process, it is possible to obtain nearly same color fading effects with that of permanganate bleaching, which means a cleaner alternative has been developed.

Ifosfamide and Doxorubicin Combination Chemotherapy for Recurrent Nasopharyngeal Carcinoma Patients

Dede, Didem Sener,Aksoy, Sercan,Cengiz, Mustafa,Gullu, Ibrahim,Altundag, Kadri Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Background: We assessed the efficacy and toxicity of ifosfamide and doxorubicin combination chemotherapy (CT) regimen retrospectively in Turkish patients with recurrent or metastatic nasopharyngeal carcinoma (NPC) previously treated with platinum-based chemotherapy. Methods: A total of thirty patients who had received cisplatin based chemotherapy/chemoradiotherapy as a primary treatment received ifosfamide 2500 $mg/m^2$ days 1-3, mesna 2500 $mg/m^2$ days 1-3, doxorubicin 60 mg/m2 day 1 (IMA), repeated every 21 days. Eligible patients had ECOG PS< 2, measurable recurrent or metastatic disease, with adequate renal, hepatic and hematologic functions. Results: Median age was 47 (min-max; 17-60). Twenty six (86.7 %) were male. Median cycles of chemotherapy for each patient were 2 (range:1-6). Twenty patients were evaluable for toxicity and response. No patient achieved complete response, with nine partial responses for a response rate of 30.0% in evaluable patients. Stable disease, and disease progression were observed in five (16.7%) and six (20.0%) patients, respectively. Clinical benefit was 46.7%. Median time to progression was 4.0 months. Six patients had neutropenic fever after IMA regimen and there were one treatment-related death due to tumor lysis syndrome in first cycle of the CT. No cardiotoxicity was observed after CT and treatments were generally well tolerated. Conclusion: Ifosfomide and doxorubicin combination is an effective regimen for patients with recurrent and metastatic NPC. For NPC patients demonstrating failure of cisplatin based regimens, this CT combination may be considered as salvage therapy.