Person: ERCAN, İLKER
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ERCAN
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İLKER
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Publication Evaluating the sensitive question methods; Recommended Uludag adjustment for the crosswise model(Taylor, 2021-10-27) Ahmadian, Robab; Ercan, İlker; Ahmadian, Robab; ERCAN, İLKER; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Temel Tıp Bilimleri/Biyoistatistik; 0000-0003-1550-639X; 0000-0002-2382-290X; AAE-5602-2019; ABF-2367-2020Sensitive questions are frequently asked in medical, psychological, and sociological research. In the social science literature, it is widely accepted that when respondents are asked such questions, social desirability bias affects survey research. Different methods in the literature aimed to reduce measurement errors such as social desirability bias and increase the reliability of participants' answers. These methods address the problem to increase the effectiveness of predictions by using indirect questioning techniques. The sensitive question methods evaluated in this study are randomized response technique, grouped answer method, unmatched-count technique, and crosswise model. These methods were evaluated with a comprehensive simulation study. The performances of the methods were evaluated according to the sample size and the sensitive issue prevalence in the hypothetical population. In the second part, in order to reduce the small sample size and low prevalence effect of the crosswise model, the Uludag correction of the crosswise model was proposed in the study. As a result, the crosswise model performs quite well compared to the other methods. In the use of the crosswise model, it is recommended to use the Uludag correction of the model proposed in this study in cases where low prevalence and small samples are studied.Publication IGF-1 and GH alterations in lambs with intestinal inflammation(TÜBİTAK, 2021-01-01) Temizel, Ethem Mutlu; Karakuş, Adil Ömer; Kavukcu, Fatih; Küçükşen, Duygu Udum; Ercan, İlker; TEMİZEL, ETHEM MUTLU; Karakuş, Adil Ömer; Kavukcu, Fatih; Küçükşen, Duygu Udum; ERCAN, İLKER; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/İç Hastalıkları Anabilim Dalı.; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Biyokimya Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; 0000-0002-6834-0808; 0000-0002-2382-290X; ECV-4083-2022; FBQ-7974-2022; JJZ-4815-2023; JJM-7084-2023; ABF-2367-2020Insulin-like growth factor-1 (IGF-1) acts on the development of internal organs such as the small intestine and muscle in all animal species. Similar to IGF-1, GH is also essential for growth and is an effective hormone on intestinal development during neonatal period. The aim of this study was to investigate the effects of diarrhea on IGF-1 and GH hormones in lambs with intestinal inflammation up to 63 days of age. The study material consisted of 15 healthy and 15 diarrheic lambs. Blood and fecal samples were collected on the first day of life and on the 7th, 14th, 21st, 35th, 49th and 63rd postnatal days consecutively. Diarrhea was observed on 6 animals on the 7th day and 9 animals on 14th day visitation. IGF-1 showed statistically significant differences (P < 0.01) between diarrheic and healthy animals on all measurement days. A significant association was found between the cut-off values determined after ROC analysis of the 7th day (Sens: 93.33%, Spec: 66.67%, P = 0.004) and 14th day (Sens: 73.33%, Spec: 80%, P = 0.0002) values of IGF-1 and diarrhea. Considering 14th day of IGF-1, a logistic regression analysis was performed, the risk of diarrhea is OR = 7.00 times higher if the concentration of the parameter is above the cut-off value. ROC analysis also showed significant cut-off values for GH on 14th day. In terms of sensitivity, the highest value was IGF-1's 7th day value, therefore it can be preferred for the determination of intestinal inflammation in cases with diarrhea. As a general evaluation, it is seen that the highest performance was given by the 7th day IGF-1 values according to the Youden's J index. In conclusion, elevations in IGF-1 and GH concentrations may be associated with intestinal inflammation. The inducing effect of the inflammatory response on IGF-I and GH may strengthen the relationship between the two parameters.Publication Statistical shape analysis of hand and wrist in paediatric population on radiographs(TÜBİTAK, 2020-05-19) Koç, Üral; Ercan, İlker; Özdemir, Senem; Bolu, Semih; Yabacı, Ayşegül; Taydaş, Onur; ÖZDEMİR, SENEM; ERCAN, İLKER; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Anatomi Anabilim Dalı.; 0000-0002-2382-290X; 0000-0002-0407-3608; ABF-2367-2020; IEX-0757-2023Background/aim: The goal of this study was to compare differences in hand and wrist shapes and to evaluate these according to growth and allometry in children on radiographs related to bone age.Materials and methods: The study included 263 males and 189 females. A total of 452 left hand and wrist radiographs were retrospectively collected. Standard anatomical landmarks marked on radiographs.Results: There were seen to be significant differences in comparisons of hand and wrist shapes according to sex (P = 0.009). The most suitable model in the growth models was seen as the Gompertz growth model for both females and males (model P < 0.001). For the relationship between shape and size to evaluate allometry, significant models were obtained in females (model P = 0.017, MSE = 0.0002) and in males (model P < 0.001, MSE = 0.0002). In our study, the difference between the sexes was found mostly in the radiocarpal region. It was observed that the deformation of the carpal bones started in the distal row carpal bones.Conclusion: Significant differences were found in hand and wrist shapes according to sex. Models for growth and allometry of hand and wrist shapes were found to be significant in children.Publication Statistical shape analysis of putamen in early-onset Parkinson's disease(Elsevier, 2021-10) Sığırlı, Deniz; Özdemir, Senem Turan; Erer, Sevda; Şahin, İbrahim; Ercan, İlker; Özpar, Rifat; Örün, Muhammet Okay; Hakyemez, Bahattin; SIĞIRLI, DENİZ; ERER ÖZBEK, ÇİĞDEM SEVDA; ERCAN, İLKER; ÖZPAR, RİFAT; HAKYEMEZ, BAHATTİN; Özdemir, Senem Turan; Şahin, İbrahim; Bursa Uludağ Üniversitesi/Tıp Fakültesi; 0000-0001-9031-3040; 0000-0002-3425-0740; 0000-0001-6649-9287; AAA-7472-2021; FPU-9468-2022; DVY-9744-2022; HII-7787-2022; ABF-2367-2020; AAH-5062-2021; AAI-2318-2021Objective: To investigate the shape differences in the putamen of early-onset Parkinson's patients compared with healthy controls and to assess and to assess sub-regional brain abnormalities. Methods: This study was conducted using the 3-T MRI scans of 23 early-onset Parkinson's patients and age and gender matched control subjects. Landmark coordinate data obtained and Procrustes analysis was used to compare mean shapes. The relationships between the centroid sizes of the left and right putamen, and the durations of disease examined using growth curve models. Results: While there was a significant difference between the right putamen shape of control and patient groups, there was not found a significant difference in terms of left putamen. Sub-regional analyses showed that for the right putamen, the most prominent deformations were localized in the middle-posterior putamen and minimal deformations were seen in the anterior putamen. Conclusion: Although they were not as pronounced as those in the right putamen, the deformations in the left putamen mimic the deformations in the right putamen which are found mainly in the middle-posterior putamen and at a lesser extend in the anterior putamen.Publication Evaluation of outlier detection method performance in symmetric multivariate distributions(Taylor & Francis, 2020-02-01) Uzabacı, Ender; Ercan, İlker; Alpu, Özlem; UZABACI, ENDER; ERCAN, İLKER; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Biyoistatistik Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; 0000-0002-9634-0055; 0000-0002-2382-290X; JPL-5273-2023; ABF-2367-2020Determining outliers is more complicated in multivariate data sets than it is in univariate cases. The aim of this study is to evaluate the blocked adaptive computationally efficient outlier nominators (BACON) algorithm, the fast minimum covariance determinant (FAST-MCD) method, and the robust Mahalanobis distance (RM) method in multivariate data sets. For this purpose, outlier detection methods were compared for multivariate normal, Laplace, and Cauchy distributions with different sample sizes and numbers of variables. False-negative and false-positive ratios were used to evaluate the methods' performance. The results of this work indicate that the performance of these methods varies according to the distribution type.Publication Evaluation of the corpus callosum shape in patients with obstructive sleep apnea(Springer Heidelberg, 2021-09-28) Güneş, Aygül; Sığırlı, Deniz; Ercan, İlker; Turan Özdemir, Senem; Durmuş, Yavuz; Yıldiz, Tekin; SIĞIRLI, DENİZ; ERCAN, İLKER; Turan Özdemir, Senem; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Anatomi Anabilim Dalı.; AAA-7472-2021; ABF-2367-2020; FPU-9468-2022Background The aim of this study was to examine whether or not there was a difference in corpus callosum shape between patients with mild to moderate and severe obstructive sleep apnea (OSA) compared with patients who have simple snoring.Methods The landmark coordinate data was obtained from the mid-sagittal magnetic resonance imaging (MRI) images of 70 patients who underwent polysomnography. For comparisons, mild and moderate OSA groups were combined and analyses were performed on three groups; simple snoring/control group, mild or moderate OSA group, and severe OSA group.Results The corpus callosum shape of controls was significantly different from that of the severe OSA group. The most prominent deformities were observed in the genu and rostral body of the corpus callosum for the patients with severe OSA. No significant difference was found between mild/moderate OSA group and simple snoring group in terms of global corpus callosum shape.Conclusion The data demonstrated that severe OSA patients have structural changes in the corpus callosum and deformities may vary as the severity of disease changes.Publication Dental caries severity and related factors of 1307 Turkish boarding school children(Wolters Kluwer Medknow Publications, 2021-10-01) Cubukcu, Çubukçu. Elbek; Ercan, İlker; Özkaya, Güven; ELBEK ÇUBUKÇU, ÇİĞDEM; ERCAN, İLKER; ÖZKAYA, GÜVEN; Bursa Uludağ Üniversitesi/Diş Hekimliği Fakültesi/Pedodonti Anabilim Dalı; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Bölümü; 0000-0002-2382-290X; 0000-0003-0297-846X; 0000-0002-1480-2907; A-4421-2016; AAH-2726-2021; ABF-2367-2020Background: In Turkey, dental caries is a disease which still has been considering as a real public health problem. School children of lower socioeconomic status had greater caries experience and higher caries severity in both primary and permanent dentitions. Aims: To determine the frequency of dental caries and its related factors among boarding school children. Patients and Methods: Cross-sectional study. We examined 1307 boarding school children aged 7-14 for caries status and its related factors. Data on dental health and its related factors were obtained from the archive of Ege Oral Health and Dentistry Association. Comparisons of caries severity (as decayed/missing/filled primary teeth, dmft/decayed/missing/filled permanent teeth, DMFT and significant caries index,) and examination years were made. Caries trend were also identified. Correlations between caries severity and its related factors were also performed. SPSS 20.0 was used for statistical analysis. Results: DMFT and SiC for DMFT of all children were 2.35 and 5.04, respectively. 70-year-old had the highest dmft, whereas 14-year-olds had the highest DMFT. No correlation was found between decreased dmft and tooth brushing frequency, regular dental check-ups, and oral hygiene status. There was a weak correlation between decreased DMFT and increased number of dental visits in 2008 and 2009. In children received more than one examination and/or treatment (n = 269), the SiC index for dmft was 10.52 in 2002. In 2004, the index decreased to 3.57. The SiC for DMFT was 4.09 in 2002 and 2004. No correlation was identified between decreased dmft and DMFT and tooth brushing frequency, regular dental check-ups, and oral hygiene status both for the years of 2002 and 2004. The mean dmft of 32 children had prophylaxis for dental caries in 2002 was significantly decreased in 2004. Conclusion: Caries prevalence and severity of boarding school children were high even they were followed-up regularly.Publication Three-dimensional analysis of craniofacial shape in obstructive sleep apnea syndrome using geometric morphometrics(Soc Chilena Anatomia, 2019-01-01) Can, Fatma Ezgi; Özdemir, Senem Turan; ÖZDEMİR, SENEM; Ercan, İlker; ERCAN, İLKER; Ocakoğlu, Gökhan; OCAKOĞLU, GÖKHAN; Çetinoğlu, Ezgi Demirdöğen; Ursavaş, Ahmet; URSAVAŞ, AHMET; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Anatomi Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Bioistatistik Anabilim Dalı.; 0000-0002-2382-290X; 0000-0002-1114-6051; 0000-0002-7400-9089; HLG-6346-2023; AAI-3169-2021; AAH-5180-2021; AAA-8734-2021; ABF-2367-2020; JPK-7012-2023Craniofacial morphology is a risk factor for obstructive sleep apnea syndrome. The general aim of this study was to investigate the craniofacial shape differences in adults with and without obstructive sleep apnea syndrome, using geometric morphometric methods. A descriptive study conducted in 106 adult Turkish subjects, consisting of 50 patients with OSAS diagnosed by polysonmography and 56 non-OSAS controls. Tlree dimensional craniofacial scanning processes were performed on patient subjects on the same day as the PSG. Twelve standard craniofacial landmarks were collected from each subject's 3D craniofacial scan. Geometric morphometric analysis was used to compare the craniofacial shape differences between the OSAS and non-OSAS control groups. No statistically significant difference in terms of general shape in face shapes was found between the OSAS group and control group. However, local significance differences were found. There were significant differences between the groups in some of the interlandmark distances: 11 % of the interlandmark distances were greater in OSAS patients, and 29 % were greater in controls. Greater measured distances in OSAS are concentrated in the nasal region. In the control group, the difference is not concentrated in a specific region. Given the relationship of craniofacial structural alterations and sleep disordered breathing, we hypothesized that inter-landmark distance measurements in the craniofacial anatomy of patients might be predictive of OSA.Publication Corpus callosum in schizophrenia with deficit and non-deficit syndrome: A statistical shape analysis(Bmj Publishing Group, 2021-10-27) Türk, Yaşar; Ercan, İlker; Şahin, İbrahim; Gürsel, Başak Erdemli; Uzunoğlu, Arda; Oğe, Cem; Beyazyüz, Elmas; Albayrak, Yakup; ERCAN, İLKER; Şahin, İbrahim; ERDEMLİ GÜRSEL, BAŞAK; Uzunoğlu, Arda; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı.; ABF-2367-2020; HII-7787-2022; AAH-6568-2021; IAK-9330-2023Background The corpus callosum (CC) is the most targeted region in the cerebrum that integrates cognitive data between homologous areas in the right and left hemispheres.Aims Our study used statistical analysis to determine whether there was a correlation between shape changes in the CC in patients with schizophrenia (SZ) (deficit syndrome (DS) and non-deficit syndrome (NDS)) and healthy control (HC) subjects.Methods This study consisted of 27 HC subjects and 50 schizophrenic patients (20 with DS and 30 with NDS). 3 patients with DS and 4 patients with NDS were excluded. Three-dimensional, sagittal, T1-spoiled, gradient-echo imaging was used. Standard anatomical landmarks were selected and marked on each image using specific software.Results As to comparing the Procrustes mean shapes of the CC, statistically significant differences were observed between HC and SZ (DS+NDS) (p=0.017, James's F-j=73.732), HC and DS (p<0.001, James's F-j=140.843), HC and NDS (p=0.006, James's F-j=89.178) and also DS and NDS (p<0.001, James's F-j=152.967). Shape variability in the form of CC was 0.131, 0.085, 0.082 and 0.086 in the HC, SZ (DS+NDS), DS and NDS groups, respectively.Conclusions This study reveals callosal shape variations in patients with SZ and their DS and NDS subgroups that take into account the CC's topographic distribution.Publication Combining binary and continuous biomarkers by maximizing the area under the receiver operating characteristic curve(Taylor & Francis, 2020-03-08) Ahmadian, Robab; Ercan, İlker; Sığırlı, Deniz; Yıldız, Abdulmecit; Ahmadian, Robab; ERCAN, İLKER; SIĞIRLI, DENİZ; YILDIZ, ABDULMECİT; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Nefroloji Anabilim Dalı.; 0000-0003-1550-639X; 0000-0002-2382-290X; AAE-5602-2019; ABF-2367-2020; AAA-7472-2021; ABF-2368-2020In any clinical case, a decision is made with the maximum possible accuracy. To achieve such accuracy, in the presence of multiple diagnostic tests or biomarkers, biomarker combinations aim to achieve maximum accuracy. As existing biomarker combination methods combine only continuous biomarkers, therefore in this study biomarker combination for binary biomarkers was created by suggesting an approach using Youden's J statistic for combining binary biomarkers. The proposed approach will facilitate binary and continuous biomarker combinations. A simulation study was conducted to compare the performance of our proposed combination approach according to different sample sizes. Both in the analysis of real data and the simulation studies for different samples, the proposed approach has been shown to yield favorable results and higher area under the curve.