Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(116)
- Şahin, Engin(48)
- Kaya, Yunus(46)
- Özen, Soner(46)
- İspirli, Hümeyra(45)
- Pat, Suat(44)
- Şenay, Volkan(42)
- Korkmaz, Şadan(36)
- Yilmaz, Mustafa Tahsin(33)
- Kutlu, Naciye(32)
- Cuce, Erdem(31)
- Öner, Erdal(31)
- Artar, Musa(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Mercan, Emin(28)
- Bayraktar, Bülent(27)
- Bayram, Sinan(27)
- Can, Zehra(25)
- Ecem Bayram, Nesrin(25)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Ayata, Ümit(21)
- Bayram, Ozkan(21)
- Dirican, Ebubekir(20)
- Abdioglu, Murat(19)
- Ayazoglu, Rabil(19)
- Birinci, Ahmet(19)
- Kamiloğlu, Aybike(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Tozlu, Alperen(18)
- Gul, Volkan(15)
- Hasar, Ugur C.(15)
- Kadakal, Mahir(15)
- Sagdic, Osman(15)
- Ergün, Mustafa(14)
- Kadakal, Huriye(14)
Yayınlar
- MakaleYalnız künye2017Scopus SJRQ1Experimental determination of cohesion & internal friction angle on conventional concretes
Pul, Selim; Ghaffari, Amir; Öztekin, Ertekin; Hüsem, Metin; Demir, Serhat
Various failure criterions have been used for the nonlinear analysis of concrete and reinforced concrete structures. To get more accurate results from the analyses, the selected failure criterion must be appropriate with the characteristics of problem and the assumptions made in the criterion should comply with the characteristics of problem. In this study, an experimental investigation was carried out to determine the cohesion (c) and internal friction angle (?) values, which are in the compressive strength range of 14.4 MPa ≤ fcm cube ≤ 47.0 MPa (2.03 ksi ≤ fcm cube ≤ 6.82 ksi) that are used in failure criterions such as Mohr-Coulomb and Drucker-Prager preferred in end unit analyses for concrete and reinforced concrete structures. Tests are performed by using the direct shear test system, which is designed and produced for this study. Finally, cohesion and internal friction angle were determined between 2.94 and 12.34 MPa (0.43 and 1.79 ksi) and 29.8 and 41.7 degrees, respectively.
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İncele - MakaleAçık Erişim2017Scopus SJRQ1Concretes with synthetic aggregates for sustainability
Tekin, Ilker; Yasin Durgun, Muhammed; Gencel, Osman; Bilir, Turhan; Brostow, Witold; Hagg Lobland, Haley E.
We have used waste marble aggregates, marble dust and fly ash from thermic power plants as fillers in concretes for replacing natural aggregates. We have used two different kinds of cements. After curing, we have determined the workability (by slump tests), air content, unit weight, Schmidt hardness, ultrasound pulse velocity, compressive strength and carbonation depth. The concretes containing waste marble at least match or exceed the workability and strength of the control concrete type. Fly ash significantly improves the workability. Utilizing waste marble aggregate at the replacement ratio of 100% along with waste marble dust, fly ash and pozzolanic cements in concrete leads to lower cost – achieving at the same time environmentally friendly production process with decreased consumption of natural resources and energy. Our work also contributes to enhancement of sustainability by finding a use for marble waste and fly ash.
AtıfScopus28WoS24OpenAlex33İncele - MakaleAçık Erişim2017Scopus SJRQ1Inhibition behaviours of some phenolic acids on rat kidney aldose reductase enzyme: an in vitro study
Alim, Zuhal; Kilinç, Namik; Şengül, Bülent; Beydemir, Şükrü
Aldose reductase (AR) inhibitors have vital importance in the treatment and prevention of diabetic complications. In this study, rat kidney AR was purified 19.34-fold with a yield of 3.49% and a specific activity of 0.88 U/mg using DE-52 Cellulose anion exchange chromatography, gel filtration chromatography and 2′5′ ADP Sepharose-4B affinity chromatography, respectively. After purification, the in vitro inhibition effects of some phenolic acids (tannic acid, chlorogenic acid, sinapic acid, protocatechuic acid, 4-hydroxybenzoic acid, p-coumaric acid, ferulic acid, vanillic acid, syringic acid, α-resorcylic acid, 3-hydroxybenzoic acid and gallic acid) were investigated on purified enzyme. We determined IC50, Ki values and inhibition types of these phenolic acids. As a result, tannic and chlorogenic acid had a strong inhibition effect. On the other hand, gallic acid had a weak inhibition effect. In this study, all phenolic acids except for chlorogenic acid and p-coumaric acid showed non-competitive inhibition effects on rat kidney AR.
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İncele - MakaleYalnız künye2017Scopus SJRQ1Toward cost-effective and energy-efficient heat recovery systems in buildings: Thermal performance monitoring
Cuce, Pinar Mert; Cuce, Erdem
Recent studies show that it is possible to reduce heating or cooling demand of a building as using heat recovery systems. Heat recovery technology is basically utilised to mitigate the heat loss, and hence energy consumption due to HVAC. Within the scope of this study, thermal comfort analyses of a test house integrated with a novel polycarbonate heat exchanger are conducted. At pre and post-retrofit case, temperature, relative humidity and CO2 measurements are carried out for a test period of one week. The results indicate that the internal CO2 concentration is not at desirable range due to lack of ventilation in the test house at the pre-retrofit case. However, following the integration of the novel ventilation system into the test house, CO2 concentration is found to be varying notably from 350 to 400 ppm which corresponds to the actual comfort conditions for indoor environments. It is also concluded from the results that the average relative humidity inside the test house at the post-retrofit case is found to be 57%, which is in the desired range whereas it is considerably high before retrofitting.
AtıfScopus26WoS25OpenAlex33İncele - MakaleAçık Erişim2017Scopus SJRQ2Prevalence and comparing of some microbiological properties, somatic cell count and antibiotic residue of organic and conventional raw milk produced in Turkey
Ürkek, Bayram; Şengül, Mustafa; Erkaya, Tuba; Aksakal, Vecihi
The aim of this study was to investigate the effects of production systems and milk collection periods on the somatic cell count (SCC), some microbiological properties, total aerobic mesophilic bacteria (TAMB), coliform, Staphylococcus aureus (S. aureus), yeast and mould) and antibiotic residue of milk; in Turkey. Milk samples were collected from 9 conventional farms and 9 organic farms during one year time, at six different months (December 2013 to October 2014), and all farms were selected from the same geographical locations. All organically managed farms had organic production certificates given by the Republic of Turkey Ministry of Food, Agriculture and Livestock. The count of TAMB, coliform, and coagulase positive S. aureus were affected by production systems at the level of p<0.01; yeast and mold, and somatic cell count (SCC) were affected at the level of p<0.05. But, differences according to months were statistically significant only on TAMB (p<0.01) and coliform (p<0.05) counts. The general means of TAMB, coliform and yeast and mould counts of the organic milk (OM) were significantly lower (p<0.05), while the general means of SCC and coagulase positive S. aureus count of the OM was significantly higher (p<0.05) compared to conventional milk (CM). Antibiotic residue was determined in one of the CM sample and in two of the OM samples. Our study is the first research that compared conventional and organic milk in Turkey. This study indicated that the microbiological quality of OM was the higher in terms of TAMB, coliform and yeast and mould, whereas was the lower in relation to SCC and coagulase positive S. aureus counts. But, the quality of both milk types should be improved.
AtıfScopus10WoS8OpenAlex12İncele - MakaleAçık Erişim2017Scopus SJRQ1A smart building material for low/zero carbon applications: Heat insulation solar glass-characteristic results from laboratory and in situ tests
Cuce, Erdem; Riffat, Saffa B.
Heat insulation solar glass (HISG) is a recently developed smart building material to minimize energy consumption of building sector. HISG might be presumed to be a conventional photovoltaic glazing product; however, it is completely unique by having some characteristic features such as superior thermal insulation, which is competitive with triple-glazed windows using argon as inert gas, acoustic and thermal comfort, self-cleaning ability owing to TiO2 nano-coating on module surface and extraordinary energy saving potential in both summer and winter. In our previous works, comprehensive experimental and numerical works have been carried out for power generation and thermal insulation performance of HISG under various climatic conditions. Within the scope of this research, optical- and lighting-related performance parameters of this smart building material are evaluated through extensive laboratory and in situ tests. Shading coefficient, visible light intensity, and UV and IR penetration are investigated via the tests conducted in real operating conditions. It is achieved from the results that the shading coefficient of HISG is only 0.136, which yields almost 80% reduction in solar heat gain compared with ordinary glazing. It is also observed from the in situ tests that HISG has a %100 UV and 99% IR blocking rate, which is of vital importance in terms of human health and thermal comfort conditions. Glaring effects are totally resolved via HISG, which is still a challenge for the buildings with conventional glazing products, especially in summer.
AtıfScopus26WoS22OpenAlex13İncele - MakaleAçık Erişim2017Scopus SJRQ1Enhancing the Damping Behavior of Dilute Zn-0.3Al Alloy by Equal Channel Angular Pressing
Demirtas, M.; Atli, K.C.; Yanar, H.; Purcek, G.
The effect of grain size on the damping capacity of a dilute Zn-0.3Al alloy was investigated. It was found that there was a critical strain value (≈1 × 10−4) below and above which damping of Zn-0.3Al showed dynamic and static/dynamic hysteresis behavior, respectively. In the dynamic hysteresis region, damping resulted from viscous sliding of phase/grain boundaries, and decreasing grain size increased the damping capacity. While the quenched sample with 100 to 250 µm grain size showed very limited damping capacity with a loss factor tanδ of less than 0.007, decreasing grain size down to 2 µm by equal channel angular pressing (ECAP) increased tanδ to 0.100 in this region. Dynamic recrystallization due to microplasticity at the sample surface was proposed as the damping mechanism for the first time in the region where the alloy showed the combined aspects of dynamic and static hysteresis damping. In this region, tanδ increased with increasing strain amplitude, and ECAPed sample showed a tanδ value of 0.256 at a strain amplitude of 2 × 10−3, the highest recorded so far in the damping capacity-related studies on ZA alloys.
AtıfScopus8WoS7OpenAlex7İncele - MakaleYalnız künye2017Scopus SJRQ2Optical and Surface Characteristics of Mg-Doped GaAs Nanocrystalline Thin Film Deposited by Thermionic Vacuum Arc Technique
Pat, Suat; Özen, Soner; Şenay, Volkan; Korkmaz, Şadan
Magnesium (Mg) is the most promising p-type dopant for gallium arsenide (GaAs) semiconductor technology. Mg-doped GaAs nanocrystalline thin film has been deposited at room temperature by the thermionic vacuum arc technique, a rapid deposition method for production of doped GaAs material. The microstructure and surface and optical properties of the deposited sample were investigated by x-ray diffraction analysis, scanning electron microscopy, energy-dispersive x-ray spectroscopy, atomic force microscopy, ultraviolet–visible spectrophotometry, and interferometry. The crystalline direction of the deposited sample was determined to be (220) plane and (331) plane at 44.53° and 72.30°, respectively. The Mg-doped GaAs nanocrystalline sample showed high transmittance.
AtıfScopus19WoS5OpenAlex59İncele - MakaleAçık Erişim2017Scopus SJRQ2The status of renewable electricity from hydropower in Turkey
Serencam, Uğur
Turkey has many problems due to its increasing energy consumption and rapid economic growth. Foreign energy dependency adversely affects sustainable development of the country by hindering its economic development. Turkey has a yearly total 433 TWh hydropower capacity and 151 TWh yearly economical capacity. The electricity demand of Turkey will reach to around 420 TWh annually by 2020. Turkey had 521 operational hydropower plants with a total capacity of almost 24,000 MW in 2014. This corresponds to 34% of the total capacity. Within the first 8 months of 2015, 8 more hydropower plants came online with a capacity of around 1,240 MW. The share of hydro in power generation capacity went up by 1% during the first five months of the year reaching 35% from its previous 34% level in 2014.
AtıfScopus2WoS2OpenAlex2İncele - Derleme MakaleAçık Erişim2017Scopus SJRQ1Correlation coefficient of single-valued neutrosophic hesitant fuzzy sets and its applications in decision making
Şahin, Rıdvan; Liu, Peide
As a combination of the hesitant fuzzy set (HFS) and the single-valued neutrosophic set (SVNS), the single-valued neutrosophic hesitant fuzzy set (SVNHFS) is an important concept to handle uncertain and vague information existing in real life, which consists of three membership functions including hesitancy, as the truth-hesitancy membership function, the indeterminacy-hesitancy membership function and the falsity-hesitancy membership function, and encompasses the fuzzy set, intuitionistic fuzzy set (IFS), HFS, dual hesitant fuzzy set (DHFS) and SVNS. Correlation and correlation coefficient have been applied widely in many research domains and practical fields. This paper, motivated by the idea of correlation coefficients derived for HFSs, IFSs, DHFSs and SVNSs, focuses on the correlation and correlation coefficient of SVNHFSs and investigates their some basic properties in detail. By using the weighted correlation coefficient information between each alternative and the optimal alternative, a decision-making method is established to handling the single-valued neutrosophic hesitant fuzzy information. Finally, an effective example is used to demonstrate the validity and applicability of the proposed approach in decision making, and the relationship between the each existing method and the developed method is given as a comparison study.
AtıfScopus118WoS94OpenAlex108İncele - MakaleAçık Erişim2017Scopus SJRQ1Thermal regulation impact of green walls: An experimental and numerical investigation
Cuce, Erdem
Green walls can be basically defined as climbing plants grown either directly against, or on support structures integrated to external building walls. Similar to other types of green infrastructure, they are in the centre of interest owing to their remarkable benefits such as reducing internal building temperatures, mitigating building energy consumption and facilitating urban adaptation to a warming climate. In this research, thermal regulation feature of green wall systems is experimentally and numerically investigated through a case study conducted in the Jubilee Campus of University of Nottingham. Internal wall temperatures are measured time-dependently for different cases and the results are compared with those of ordinary walls for a reliable and realistic approach. Different sky conditions are also considered within the scope of this research as an independent variable. Experimental results are verified by numerical models carried out in Ecotect. The results reveal that an average of 2.5 °C reduction in internal wall temperature can be achieved via green walls with about 10 cm thick climbing vegetation of Hedera helix, which is very promising.
AtıfScopus168WoS138OpenAlex178İncele - BildiriAçık Erişim2017Optimization of RT superplasticity of UFG Zn-22Al alloy by applying ECAP at different temperatures and phase regions
Demirtas, M.; Yanar, H.; Purcek, G.; Estrin, Y.; Liao, X.
Zn-22Al alloy was subjected to either one-step or two-step equal channel pressing (ECAP) to investigate the effect of processing temperature on its microstructure and room temperature (RT) superplasticity. In one-step ECAP processes, 4 passes ECAP were applied to the alloy at different temperatures: RT, 100°C and 250°C in two-phase region below eutectoid temperature and 350°C in single-phase region above eutectoid temperature. In two-step ECAP processes, one-step ECAP-processed samples were subjected to four more passes ECAP at RT. Considering the one-step ECAP processing, RT superplasticity increased with decreasing ECAP temperature as expected, and the highest RT superplasticity was achieved as 350% after 4 passes ECAP at RT. On the other hand, application of 4 more passes ECAP at RT to the sample showing the lowest superplastic elongation after one-step ECAP (the sample processed at 350°C) resulted in the maximum RT elongation of 400% at a high strain rate of 5×10-2 s-1. These results suggest that first step temperature of two-step ECAP process is needed to increase above the eutectoid point of Zn-22Al alloy to achieve high RT superplasticity. These results were attributed to the changes in microstructure inside the single-phase and two-phase regions during the processes.
AtıfScopus12WoS10OpenAlex9İncele - MakaleAçık Erişim2017Scopus SJRQ2Effect of laser irradiation on superconducting properties of bulk MgB2 sintered at different temperatures
Erdem, O.; Yanmaz, E.
The surfaces of MgB2 bulk samples produced by a pellet/closed tube method at two different sintering temperatures of 650 and 850 °C, after hot pressing at 200 °C, were irradiated with the same irradiation dose by using an Nd:YVO4 laser in order to study the possible potentiality of laser irradiation to improve pinning performances and critical current density of MgB2 superconductor. The measurements showed that the magnetic field dependence of the critical current density values of irradiated sample sintered at 650 °C slightly increased with a narrowing in superconducting transition region as compared to the reference sample sintered at same temperature. However, irradiated sample sintered at 850 °C showed a decrease in pinning performance and similar critical temperature values as compared to the corresponding reference sample. From these results it can be said that the same laser irradiation dose affects superconducting properties of bulk MgB2 in different ways depending on sintering temperature of the superconductor.
AtıfScopus4WoS4OpenAlex4İncele - MakaleAçık Erişim2017Scopus SJRQ2The substrate effect on Ge doped GaN thin films coated by thermionic vacuum arc
Özen, Soner; Korkmaz, Şadan; Şenay, Volkan; Pat, Suat
This study focuses on characterization and understanding of the substrate effect on Ge doped GaN thin films coated onto transparent substrates. The produced films were deposited onto unheated glass and unheated polyethylene terephthalate by using thermionic vacuum arc technique. Gallium nitride and germanium pellets were used in the thin film production. Reflectance, refractive index and thicknesses of Ge doped GaN thin films were measured by optical interferometer using Cauchy model for fitting. The transmittances were determined in the wavelength range between 200 and 1000 nm by using UV–Vis double beam spectrophotometer. The optical Tauc method was used to determine the band gap energies of produced thin films. Surface morphologies of produced thin films were characterized by atomic force microscopy and also field emission scanning electron microscopy. In conclusion, the substrate effect on the optical and morphological properties of the produced thin films was observed.
AtıfScopus8WoS8OpenAlex9İncele - MakaleYalnız künye2017Scopus SJRQ2Highly Enantioselective Production of Chiral Secondary Alcohols Using Lactobacillus paracasei BD101 as a New Whole Cell Biocatalyst and Evaluation of Their Antimicrobial Effects
Yılmaz, Durmuşhan; Şahin, Engin; Dertli, Enes
Chiral secondary alcohols are valuable intermediates for many important enantiopure pharmaceuticals and biologically active molecules. In this work, we studied asymmetric reduction of aromatic ketones to produce the corresponding chiral secondary alcohols using lactic acid bacteria (LAB) as new biocatalysts. Seven LAB strains were screened for their ability to reduce acetophenones to their corresponding alcohols. Among these strains, Lactobacillus paracasei BD101 was found to be the most successful at reducing the ketones to the corresponding alcohols. The reaction conditions were further systematically optimized for this strain and high enantioselectivity (99%) and very good yields were obtained. These secondary alcohols were further tested for their antimicrobial activities against important pathogens and significant levels of antimicrobial activities were observed although these activities were altered depending on the secondary alcohols as well as their enantiomeric properties. The current methodology demonstrates a promising and alternative green approach for the synthesis of chiral secondary alcohols of biological importance in a cheap, mild, and environmentally useful process.
AtıfScopus41WoS35OpenAlex38İncele - MakaleYalnız künye2017Scopus SJRQ2Investigation on the physical properties of C-doped ZnO thin films deposited by the thermionic vacuum arc
Mohammadigharehbagh, Reza; Özen, Soner; Hakan Yudar, H.; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan
The aim of this study is to determine some physical properties of C-doped ZnO coated on a glass substrate by using the thermionic vacuum arc method. The produced C-doped ZnO thin film is characterized by using several analysis techniques. The produced thin film has a cubic crystal structure, high transmittance in the visible region, symmetrical surface distribution, and optical band gap energy of 3.34 eV. According to the XRD analysis of the produced thin film, it is a fullerene (C60)-doped polycrystalline ZnO. Hardness value and Young's modulus value were determined as 8 GPa and 140 GPa, respectively. These physical properties are adequate for future transparent electrode applications.
AtıfScopus15WoS15OpenAlex16İncele - MakaleAçık Erişim2017Scopus SJRQ1Thermal performance assessment of a novel liquid desiccant-based evaporative cooling system: An experimental investigation
Cuce, Pinar Mert
Energy consumption in buildings due to heating, cooling and air conditioning (HVAC) systems has a steadily growing trend as a consequence of enhanced indoor thermal comfort conditions. The role of cooling in HVAC oriented energy consumption is remarkable especially in regions with extreme climatic conditions such as Africa and Middle East. In hot and arid climates, cooling demand is usually met by cost-effective evaporative cooling solutions. However, in hot and humid climates, evaporative cooling systems are not capable of providing cooling as the outdoor air is already almost saturated in most cases. Therefore in this research, a novel desiccant-based evaporative cooling system is presented. For different values of inlet supply air temperature and relative humidity provided by a standard environmental chamber, temperature and relative humidity values are measured experimentally at the inlet and outlet of dehumidification and humidification unit, respectively. Since the main purpose of the system developed is to provide cost-effective thermal comfort conditions especially in humid climates, dehumidification effectiveness is calculated for each case tested. The results indicate that the system provides attractive findings for temperate and humid climatic conditions, where stand-alone evaporative cooling systems are inconclusive. For a case of average inlet relative humidity of 94.7% and average inlet air temperature of 38.6 °C, the average outlet relative humidity and air temperature are determined to be 65.5% and 33.3 °C, respectively. An average of 5.3 °C reduction is achieved in supply air temperature as well as an average of 63.7% dehumidification effectiveness which is attractive and promising.
AtıfScopus35WoS32OpenAlex37İncele - MakaleAçık Erişim2017Scopus SJRQ2Teaching word meanings to students at different reading ability: A controlled assessment of the contextual-based vocabulary instruction on reading comprehension
Ilter, Ilhan
The purpose of this study was to examine the effectiveness of contextual-based vocabulary instruction on reading comprehension of seventh-grade students at different reading ability levels in social studies. The Sentence Verification Technique test consisted of 16-items was used to determine participants' reading comprehension skills. In addition, a semi-structured interview form was used to describe participants' perceptions and experiences related to the vocabulary intervention program activities. The experimental condition received a contextual-based vocabulary instruction intervention program for eight weeks in 10 sessions; in contrast to the control condition participated in a wide reading program. As a result, this study yielded two findings: First, the results indicated that teaching students how to use contextual analysis to infer word meanings from context improved significantly their own reading comprehension scores. Second, the qualitative findings showed that poor readers could be able unlock the complexity of the meanings of unknown words and use the cognitive strategies that required to overcome their reading difficulties while reading through explicit instruction. The results suggested that it seemed as though the context-based vocabulary instruction used in this study to improve reading comprehension scores was a fairly powerful procedure for all students, both poor readers and average-high readers in the experimental condition.
AtıfScopus6WoS5OpenAlex10İncele - MakaleYalnız künye2017Scopus SJRQ1Cross-entropy measure on interval neutrosophic sets and its applications in multicriteria decision making
Şahin, Rıdvan
The neutrosophic set model is an important tool for dealing with real scientific and engineering applications because it can handle not only incomplete information but also the inconsistent information and indeterminate information which exist commonly in real situations. In this paper, we firstly propose two practical techniques converting an interval neutrosophic set into a fuzzy set and a single-valued neutrosophic set, respectively. Then, we define the interval neutrosophic cross-entropy in two different ways, which are based on extension of fuzzy cross-entropy and single-valued neutrosophic cross-entropy. Additionally, two multicriteria decision-making methods using the interval neutrosophic cross-entropy between an alternative and the ideal alternative are developed in order to determine the order of the alternatives and choose most preferred one(s). Finally, an illustrative example is presented to verify the proposed methods and to demonstrate their effectiveness and practicality.
AtıfScopus65WoS62OpenAlex72İncele - MakaleAçık Erişim2017Scopus SJRQ2Comparison of telomere length and insulin-like growth factor-binding protein 7 promoter methylation between breast cancer tissues and adjacent normal tissues in Turkish women
Kaya, Zehra; Akkiprik, Mustafa; Karabulut, Sevgi; Peker, Irem; Gullu Amuran, Gokce; Ozmen, Tolga; Gulluoglu, Bahadır M.; Kaya, Handan; Ozer, Ayse
Background: Both insulin-like growth factor-binding protein 7 (IGFBP7) and telomere length (TL) are associated with proliferation and senescence of human breast cancer. This study assessed the clinical significance of both TL and IGFBP7 methylation status in breast cancer tissues compared with adjacent normal tissues. We also investigated whether IGFBP7 methylation status could be affecting TL. Methods: Telomere length was measured by quantitative PCR to compare tumors with their adjacent normal tissues. The IGFBP7 promoter methylation status was evaluated by methylation-specific PCR and its expression levels were determined by western blotting. Results: Telomeres were shorter in tumor tissues compared to controls (P<.0001). The mean TL was higher in breast cancer with invasive ductal carcinoma (IDC; n=72; P=.014) compared with other histological type (n=29), and TL in IDC with HER2 negative (n=53; P=.017) was higher than TL in IDC with HER2 positive (n=19). However, telomeres were shortened in advanced stages and growing tumors. IGFBP7 methylation was observed in 90% of tumor tissues and 59% of controls (P=.0002). Its frequency was significantly higher in IDC compared with invasive mixed carcinoma (IMC; P=.002) and it was not correlated either with protein expression or the other clinicopathological parameters. Conclusion: These results suggest that IGFBP7 promoter methylation and shorter TL in tumor compared with adjacent tissues may be predictive biomarkers for breast cancer. Telomere maintenance may be indicative of IDC and IDC with HER2 (−) of breast cancer. Further studies with larger number of cases are necessary to verify this association.
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