A decision support tool for the analysis of pricing, investment and regulatory processes in a decentralized electricity market

After the liberalization of the electricity generation industry, capacity expansion decisions are made by multiple self-oriented power companies. Unlike the centralized environment, decision-making of market participants is now guided by price signal feedbacks and by an imperfect foresight of the future market conditions (and competitor actions) that they will face. In such an environment, decision makers need to better understand long-term dynamics of the supply and demand sides of the power market. In this study, a system dynamics model is developed, to better understand and analyze the decentralized and competitive electricity market dynamics in the long run. The developed simulation model oversees a 20-year planning horizon; it includes a demand module, a capacity expansion module, a power generation module, an accounting and finance module, various competitors, a regulatory body and a bidding mechanism. Many features, singularities and tools of decentralized markets, such as; capacity withholding, enforced divestment, long-term contracts, price-elastic demands, incentives/disincentives, are also incorporated into the model. Public regulators and power companies are potential users of the model, for learning and decision support in policy design and strategic planning. Results of scenario analysis are presented to illustrate potential use of the model.

Anomalous Origin of Left Internal Thoracic Artery From The Second Intercostal Artery

Left internal thoracic artery (LITA) has increased importance and common use in coronary bypass grafting because of long-term better patency rate and improvement in both the duration and quality of survival of patients. LITA is a branch of the first part of the subclavian artery. We report a case in which the LITA originated from the second left intercostal artery. A 71-year-old man with a history of angina pectoris for 1 month was admitted to the hospital because of progressive increase in anginal symptoms. During the operation, it was noted that the LITA originated from the second intercostal artery. LITA used as a free graft. LITA was anastomosed to the left anterior descending coronary artery. He was free of symptoms 4 weeks after operation. To our knowledge, this is the first reported case of the LITA originating from the second intercostal artery

Predictors For Progression Of Tricuspid Insufficiency Following Left-Sided Valvular Surgery: A Retrospective Cohort Study

Background: The operative indications for severe tricuspid insufficiency in patients undergoing left-sided valvular surgery are well defined; however, for mild and moderate insufficiency, the findings are still controversial. In this study, we aimed to document the prognostic parameters for progression of tricuspid insufficiency in patients undergoing left-sided valvular surgery. Methods: 135 patients undergoing mitral valve +/- coronary bypass surgery were retrospectively examined. Patients with simultaneous tricuspid valve surgery were excluded. Demographic, clinical, and laboratory findings were recorded and the relationship with progression of tricuspid insufficiency was studied. Results: Valvular pathology was rheumatic in origin in 72.6% of patients. Tricuspid insufficiency was progressed in 69 (51.1%) of patients, while it did not change in 66 (48.9%) patients. Echocardiographic parameters recorded during follow-up revealed that left ventricular end-diastolic diameter decreased, while there was no significant change in right ventricular end-diastolic diameter. Tricuspid insufficiency was directly related with right ventricular end-diastolic diameter (P<.05), while no relationship was documented with left ventricular end-diastolic diameter. There was a statistically significant correlation between postoperative progression of tricuspid insufficiency and left atrial diameter; however, no relationship was documented with age, sex, valvular disease etiology, comorbidities, or preoperative atrial fibrillation. Risk factor analysis revealed that left atrial diameter was the only prognostic factor. Conclusion: The indications for mild and moderate tricuspid insufficiency are still not clear for patients undergoing left-sided valvular surgery. In this study, we documented that left atrial dilatation was a prognostic factor for progression of postoperative tricuspid insufficiency. In this group of patients, presence of left atrial dilatation may be an indication for tricuspid valve intervention.WoSScopu

The Impact Of Red Cell Distribution Width And Neutrophil/Lymphocyte Ratio On Long-Term Survival After Pulmonary Resection For Non-Small Cell Lung Cancer

Red cell distribution width (RDW) and Neutrophil/Lymphocyte Ratio (NLR) are widely available blood tests which can be used to reflect patients' inflammatory status. We investigated the effects of RDW and NLR levels on long-term survival after pulmonary resection for non-small cell lung cancers. Data were compiled retrospectively from 249 patients. We found a significant correlation between higher RDW and NLR levels and poorer prognosis. Overall survival rates of patients with high and normal RDW levels were 42 +/- 7 and 84 +/- 12 months, respectively (p= 0.019). In addition, disease free survival rates of patients with high and normal RDW levels were 62 +/- 6 and 76 +/- 4 months (p= 0.047), respectively. When NLR levels were divided into tertiles we observed significantly poorer overall and disease free survival in ascending tertiles. The overall and disease free survival rates in the lower through upper tertiles were; 88 +/- 6, 80 +/- 6, 50 +/- 5 months for overall and 87 +/- 6, 77 +/- 6, 47 +/- 5 months for disease free survival (p< 0.001). In conclusion, the ability to accurately predict sub-sets with poorer outcomes among patients who had undergone pulmonary resection for non-small cell lung cancers is important. RDW and NLR are biomarkers which could influence patients categorization in this regard. Preoperative measurement of these potential markers are simple, adds no additional cost to routine preoperative workup and can be used to identify patients with poorer prognosis.WoSScopu

Comparison Of Risk Scoring Systems In Congenital Heart Surgery

Hacettepe University Faculty of Medicine Department of Cardiovascular Surgery; data of 413 patients under 18 years old who had congenital heart surgery were evaluated between 01.01.2011-30.10.2012 and risk scorings were made by "RACHS-1 (Risk Adjustment in Congenital Heart Surgery)", "Aristotle Basic Complexity Score (ABS)" and "Aristotle Comprehensive Complexity Score (ACS)" systems used in evaluation of the risk of mortality and morbidity in congenital heart surgery. Data obtained were compared by Mann-Whitney U test and how effective these systems were in evaluating mortality and morbidity and their superiorities over each other were examined. Following the research, it was observed that all three systems were effective in evaluating mortality and morbidity; the most successful of them in foreseeing the event was the ACS system, ACS system was followed by RACHS-1 system and ABS system was the most incapable of these in foreseeing the event. It was seen that in detecting time related mortality, rating of these tests changed, RACHS-1 system detected the time related mortality best. It was also seen that with RACHS-1 system, a previously evaluated concept, it was possible to determine morbidity.WoSScopu

Combined Use Of Barrier Methods To Prevent Pericardial Adhesions: Is It Always Better?

Background: This study aims to investigate the effects of combined and individual use of pericardial closure, expanded polytetrafluoroethylene membrane and resorbable adhesion barrier (REPEL-CV (R)) on pericardial adhesions on a rabbit model. Methods: Thirty rabbits were randomly assigned to six groups: control, pericardium, expanded polytetrafluoroethylene, resorbable membrane, expanded polytetrafluoroethylene + resorbable membrane, and pericardium + resorbable membrane. At the postoperative five weeks, the tenacity of the adhesions was evaluated using a qualitative grading system, and histological specimens were examined. Results: Resorbable membrane group had significantly lower tenacity scores, compared to the control, pericardium, and expanded polytetrafluoroethylene groups (p<0.01). The scores of the expanded polytetrafluoroethylene + resorbable membrane and pericardium + resorbable membrane groups were lower than the control group (p<0.05 and p<0.01 respectively). Combined use of resorbable membrane, compared to the solitary use, did not produce significantly different tenacity scores. Macroscopically, in the resorbable membrane group after sternotomy, there were filmy adhesions over the epicardium which could be easily dissected digitally. In the expanded polytetrafluoroethylene + resorbable membrane and pericardium + resorbable membrane groups, there were also adhesions beneath the sternum. Conclusion: Resorbable membrane was effective in reducing postoperative pericardial adhesions when used alone or in combination with expanded polytetrafluoroethylene membrane or pericardial closure. Solitary use of resorbable membrane, compared to combined use, can be preferable, since the addition of expanded polytetrafluoroethylene membrane and pericardial closure increase substernal fibrosis.WoSScopu

Küçük Hücreli Dışı Akciğer Kanseri’nde ERCC1’in Prognostic Rolü ve 18F-FDG Tutulumu ile Korelasyonu

ERCC1 protein pozitifliği ile platin bazlı kemoterapi arasında direnç olduğu bulunmuştur. FDG tutulumunun ise KHDAK'da prognostik bir belirteç olduğu, TNM sınıflamasının ötesinde prognostik bilgi verdiği kabul edilmektedir. Bu çalışmanın amacı, KHDAK nedeniyle akciğer rezeksiyonu uy-gulanmış olan hastalarda hem ERCC1 proteininin prognostik değerinin hem de ERCC1 ekspresyonunun PET'te 18F-FDG tutulumu ile olan korelasyonunu araştırılmasıdır. KHDAK tanısıyla PET sonrası akciğer rezeksiyonu uygulanmış olan 71 hasta retrospektif olarak incelendi. ERCC1 ekspresyonu olan hastaların sağkalımı istatistiksel olarak anlamlı olmasa da daha iyi bulundu (p= 0.067). Adjuvan tedavi almayan hastalarda ERCC1 pozitif hastalarda anlamlı sağkalım avantajı olduğu görüldü (p= 0.047). Yüksek SUVmax değerleri kötü prognozu gösterdi (hazard ratio [HR]: 1.10; 95% CI, 1.02-1.18; p= 0.009). ERCC1 ekspresyonu ile ortalama SUVmax değerleri arasında anamlı korelasyon saptanmadı (p= 0.915). SUVmax >=2.5 olan hastalarda, ölen hastalarda ERCC1 pozitifliği %57.4, yaşayan hastalarda %29.4 olarak saptandı (p= 0.048). Yüksek 18F-FDG tutulumu değerleri ile kötü prognoz ilişkisi bu çalışma ile tekrar gösterilmiş oldu. Ancak, ERCC1 ekspresyonu ile SUVmax değerleri arasında güçlü bir korelasyon saptanamadıERCC1 is a protein which is found to be associated with resistance to platinum-based chemotherapy. FDG uptake is considered as a prognostic marker in patients with NSCLC and provides information beyond that of TNM staging. The aim of this study is to examine both prognostic values of ERCC1 expression and 18F-FDG uptake on PET and their relationship in patients who underwent pulmonary resection for NSCLC. Although high expression of ERCC1 was found to be associated with better survival, the difference was not considered as statistically significant (p= 0.067). There is a significant survival advantage in ERCC1 (+) patients who did not receive adjuvant therapy (p= 0.047). High maximal standard uptake value (SUVmax) was found to be associated with poor survival (hazard ratio [HR]: 1.10; 95% CI, 1.02-1.18; p= 0.009). Correlation between ERCC1 expression and mean SUVmax was statistically insignificant (p= 0.915). Among patients with SUVmax ?2.5, ERCC1 positivity was 57.4% in patients who survived and 29.4% in patients who died which was statistically significant (p= 0.048). The association between high 18F-FDG uptake on PET and poor outcome was confirmed, but we failed to detect a powerful correlation between ERCC1 expression and SUVma

Prognostic Role of Ercc1 Protein Expression and Its Correlation with 18F-Fdg Uptake on Pet in Patients with Resected Non-Small Cell Lung Cancer

ERCC1 is a protein which is found to be associated with resistance to platinum-based chemotherapy. FDG uptake is considered as a prognostic marker in patients with NSCLC and provides information beyond that of TNM staging. The aim of this study is to examine both prognostic values of ERCC1 expression and 18F-FDG uptake on PET and their relationship in patients who underwent pulmonary resection for NSCLC. Although high expression of ERCC1 was found to be associated with better survival, the difference was not considered as statistically significant (p= 0.067). There is a significant survival advantage in ERCC1 (+) patients who did not receive adjuvant therapy (p= 0.047). High maximal standard uptake value (SUVmax) was found to be associated with poor survival (hazard ratio [HR]: 1.10; 95% CI, 1.02-1.18; p= 0.009). Correlation between ERCC1 expression and mean SUVmax was statistically insignificant (p= 0.915). Among patients with SUVmax >= 2.5, ERCC1 positivity was 57.4% in patients who survived and 29.4% in patients who died which was statistically significant (p= 0.048). The association between high 18F-FDG uptake on PET and poor outcome was confirmed, but we failed to detect a powerful correlation between ERCC1 expression and SUVmax.WoSScopu