154 research outputs found
Analytic modeling of loss and cross-coupling in capacitive micromachined ultrasonic transducers
The structural loss mechanism of capacitive micromachined ultrasonic transducer (cMUT) is investigated using finite element analysis and the normal mode theory. A single micromachined transducer membrane on an infinite silicon substrate is simulated by incorporating absorbing boundary conditions in the finite element method. This enables direct evaluation of the mechanical impedance of the membrane. Furthermore, the field distribution along the thickness of the silicon substrate due to outward radiating wave modes is obtained. The normal mode theory is applied to extract the contributions of different wave modes to the complicated field distributions. It is found that, the lowest order Lamb wave modes are responsible for the loss. Evaluation of absolute and relative power losses due to individual modes indicate that the lowest order anti-symmetric (A0) mode is the dominant radial mode in agreement with experimental measurements. The results of the analysis are used to derive a detailed equivalent circuit model of a cMUT with structural loss
Organik Tavukçuluk Projesi (Organik Yumurta Tavukçuluğu)
Bu çalışmada, dış kaynaklı beyaz (Lohmann LSL) ve yerli kahverengi (ATAK-S) yumurtacı tavukların organik ve konvansiyonel sistemde yetiştirilmelerinin yumurta verim performansı, yumurta iç ve kabuk kalitesi, yumurtanın kısımları, protein oranı, kolesterol miktarı ile yağ asitleri kompozisyonu üzerine etkileri incelenmiştir.
Her iki yetiştirme sistemde de beyaz yumurtacılar yerli kahverengi yumurtacılara kıyasla daha yüksek yumurta verim ve ağırlığına sahip olmuşlardır. Organik sistemde beyaz yumurtacıların yumurta verimi ve toplam yumurta sayısı düşerken, kahverengi yumurtacıların yükselmiştir. Beyaz yumurtacıların yaşama gücü kahverengi yumurtacılara kıyasla organik sistemde % 14 düzeyinde daha düşük olup, ölümler kanibalizmden kaynaklanmıştır. Organik sistemde yumurta ağırlığı beyaz yumurtacılarda rakamsal, kahverengi yumurtacılarda ise istatistiki olarak artmıştır. Organik sistemde yem tüketimi yönünden genotipler arasında fark bulunmazken, kafes sisteminde kahverengi yumurtacılar beyaz yumurtacılardan % 3.77 oranında daha fazla yem tüketmişlerdir. Beyaz yumurtacılar kahverengi yumurtacılara kıyasla her iki yetiştirme sisteminde de daha düşük yemden yararlanma değerine sahip olmuşlardır. Yemden yararlanma değeri organik sistemde kafes sistemine kıyasla beyaz yumurtacılarda % 21.0, kahverengi yumurtacılarda ise % 8.8 düzeyinde kötüleşmiştir. Yumurta kabuk ve iç kalitesi beyaz yumurtacılarda daha iyidir.
Yetiştirme sisteminin yumurta ak, sarı ve kabuk oranına, genotipin ak ve kabuk oranı üzerine olan etkileri önemli bulunmuştur (P<0,05). Her iki genotipte de organik yumurtaların kabuk oranının konvansiyonele kıyasla daha yüksek olduğu görülmüştür. Organik ve konvansiyonel beyaz yumurtalarda, kahverengi yumurtalara göre daha yüksek kabuk oranı olduğu tespit edilmiştir.
Yumurta protein oranı üzerinde yetiştirme sisteminin etkisi önemsiz (P>0,05), genotip etkisi önemli (P0,05).
Organik ve konvansiyonel yumurtaların linolenik ve toplam omega-3 yağ asitleri ile omega-6/omega-3 oranları arasında önemli (P<0,05) farklılıklar bulunmuştur. Organik yumurtaların omega-3 içeriği konvansiyonel yumurtalardan daha düşük, omega-6/omega-3 oranı ise daha yüksektir.
Sonuç olarak, yetiştirme sistemi ve genotip incelenen yumurta verim ve kalite parametreleri üzerine önemli etkilerde bulunmuştur
Organik Tavukçuluk Projesi (Organik Etlik Piliç Yetiştiriciliği)
Ülkemizde bu konu ile ilgili olarak ilk olan bu projede organik ve konvansiyonel etlik piliç yetiştiriciliği verim, kalite ve maliyet yönleriyle karşılaştırılmıştır. Projede aynı zamanda, organik etlik piliç yetiştiriciliğinde yerli yem katkı maddesi olan eterik yağ katkısının kullanılabilirliği araştırılmıştır. Projede yavaş gelişen ve hızlı gelişen etlik piliç genotipleri kullanılmıştır. Yavaş gelişen etlik piliçler hem organik hem de konvansiyonel, hızlı gelişen etlik piliçler sadece konvansiyonel şartlarda yetiştirilmiştir.
Yavaş gelişen etlik piliçler organik sistemde daha iyi yemden yararlanma değeri gösterirken, konvansiyonel sistemde yetiştirilen hızlı gelişen etlik piliçlere göre yaklaşık % 51 daha kötü yemden yararlanma değeri elde edilmiştir. Kalite parametreleri açısından farklılık genelde genotip farklılığından kaynaklanmıştır. Organik sistem kalite, lezzet ve sağlık açısından incelenen parametrelerde herhangi bir iyileşme sağlamamıştır. Omega-3 miktarının organik piliç etinde daha az çıkması organik sistem için beklenenin tam tersi bir durum olup, bu konuda daha fazla çalışmaya ihtiyaç vardır.
Eterik yağ karışımı katkısı, konvansiyonel hızlı gelişen grupta yemden yararlanma ve mortalite oranında önemli iyileşmeler sağlarken, yavaş gelişen etlik piliç gruplarında incelenen özellikler açısından herhangi bir farklılık oluşturmamıştır.
Gerek yemden yararlanma değerindeki kötüleşmenin, gerekse maliyetlerdeki yüksekliğin, organik piliç etinin konvansiyonel piliç etine kıyasla 2 katı fiyatla satılması ile giderilebileceği ve daha karlı bir üretim olacağı görülmüştür.
Bu proje ile ülkemizde ilk kez organik etlik piliç yetiştiriciliği başarılı bir şekilde bilimsel olarak incelenmiş ve uygulanmıştır.
Yem kompozisyonu, genotip ve gezinme alanı bitki örtüsü ile organik sistemde yetiştirilen etlik piliçlerin besi performansı ve et kalitesi arasındaki ilişkilerin ortaya konduğu daha fazla sayıda araştırmaya ihtiyaç vardır
Majör Depresif Bozukluğu Olan Ergenlerde İntihar Girişimi
Aim:In this study, we aimed to assess the sociodemographic and clinical characteristics of adolescents diagnosed with major depressive disorder (MDD), with and without suicide attempts, as well as to investigate the factors predicting suicide attempts.Materials and Methods:This study included 151 adolescents aged between 12 and 18 years, who were diagnosed with MDD between January 2021 and June 2022. This study has a retrospective design, and data including family sociodemographic characteristics, suicide attempts and characteristics, non-suicidal self-injury (NSSI) attempts, history of abuse, comorbid psychiatric disorders, and scores on depression and anxiety scales were extracted from the cases’ polyclinic records. The participants were divided into two groups as those with suicide attempts (n=40) and those without suicide attempts (NSSI n=111), and the sociodemographic and clinical data were compared between the groups. In addition, a binary logistic regression analysis was performed to identify the predictors for suicide attempts.Results:The results of the study revealed that the suicide attempt group had a higher age (p=0.023), less maternal years of education (p=0.026), higher rates of self-injurious behavior (p<0.001), more severe depression (p=0.021) and anxiety (p=0.018) symptoms, and higher rates of history of childhood abuse (p=0.001). The binary logistic regression analysis performed to predict suicide attempts in those with an MDD diagnosis determined NSSI and history of abuse to be predictors.Conclusion:A better understanding of predictive factors of suicide attempts in adolescents with depression may help establish targets for early intervention and inform more effective prevention strategies. Particularly, the presence of self-injurious behaviors and history of childhood abuse should be warning for suicide attempts
Association between aortic stiffness and left ventricular function in inflammatory bowel disease
Background: Recent studies have reported an increased incidence of both aortic stiffness and left ventricular (LV) systolic and diastolic dysfunction in patients with inflammatory bowel disease (IBD). However, the association between aortic stiffness and the LV function has not been fully defined. We aimed to investigate the relationship between aortic stiffness and the LV function in IBD patients.
Methods and Results: Seventy-two patients with IBD (56 cases of ulcerative colitis and 16 cases of Crohn’s disease) and 50 healthy controls were consecutively enrolled in this study. The LV systolic and diastolic functions were assessed using conventional echocardiographic techniques, including tissue Doppler echocardiography. The degree of aortic strain and distensibility were calculated based on the aortic diameters measured on M-mode echocardiography at the level of 3 cm above the aortic valve and the blood pressure values obtained on sphygmomanometry. There were significant differences between the IBD and control group in the degree of aortic strain and distensibility. Significant differences were also observed between the patient and control groups in the parameters of the LV systolic and diastolic functions. Moreover, aortic stiffness was found to be associated with the LV function in the patient group.
Conclusions: There is a significant relationship between aortic stiffness and LV systolic and diastolic dysfunction in patients with IBD, based on the findings of this study. The parameters of aortic elasticity measured according to 2-dimensional echocardiographic methods can be beneficial for predicting early cardiovascular risk in cases of IBD. (
Impact of transcatheter aortic valve implantation on the left ventricular mass
Background: Aortic stenosis (AS) induces pressure overload of the left ventricle (LV) and results in left ventricular hypertrophy. The remodeling of the LV in patients with AS is a complex process including structural and functional disturbances. After aortic valve replacement, reverse remodeling of LV begins. The aim of this study was to evaluate the impact of transcatheter aortic valve ımplantation (TAVI) on LV mass (LVM) in early and mid-term follow-ups after the procedure.
Methods and Results: We enrolled consecutive 75 patients who underwent successful TAVI. Transthoracic echocardiography was performed prior to TAVI and at hospital discharge, in the 1st month and 6th month of the follow-ups. The mean LV ejection fraction improved significantly after TAVI (54.2 ± 15.0% to 57.3 ± 11.7%, p < 0.001). There were no significant changes between the baseline and discharge mean LVM and LVM index values (LVMI; p = 0.1). However, LVMI decreased significantly in the 1st month of follow-up compared to baseline (123.3 ± 20.3 to 127.9 ± 21.3 g/m2, respectively, p < 0.001). Also, significant regression of LVM was observed at the 1st month of follow-up compared to baseline (228.3 ± 33.5 g vs. 236.5 ± 34.2 g, respectively, p < 0.001). Furthermore, the significant regression in both of LVM and LVMI continued at 1st and 6th months of the follow-ups (p < 0.001).
Conclusions: A significant regression of LVM was observed after TAVI. These changes may have prognostic value in patients with severe AS
Theory of Mind: Development, Neurobiology, Related Fields and Neurodevelopmental Disorders
Theory of mind is a social cognition skills demonstrated its importance in the last forty years with psychiatric clinical trials. Theory of mind is seen as an effective and necessary skill in the social function-ing of human who is a social creature as the ability to recognize the mental states and emotions of others. In the first six years of life, theory of mind has been associated with many fields. Findings related to many neurobiological bases, such as limbic-paralimbic structures, prefrontal cortex, which start with mirror neurons, help this sense of meaning. Areas associated with theory of mind development provide better understanding of theory of mind skills and deficits, the first psychopathology studies have been carried out in children with autism, and the studies about theory of mind skills in the diagnosis of neurodevelopmental disorders are becoming more and more interesting. In this review, theory of mind development, neurobiological basis and related areas will be explained and the relation of theory of mind with psychopathology will be examined
Immediate recovery of the left atrial and left ventricular diastolic function after transcatheter aortic valve implantation: A transesophageal echocardiography study
Background: Chronic increased afterload due to severe aortic stenosis (AS) results in compensatory concentric left ventricular (LV) hypertrophy and LV dysfunction. These in turn cause remodeling of the left heart. The aim of this study was to investigate the acute effect of transcatheter aortic valve implantation (TAVI) on left atrial (LA) mechanics and LV diastolic function.
Methods: The study consisted of a total of 35 consecutive patients (mean age was 77.7 ± 5.0 years, 25 female) undergoing TAVI. All TAVI procedures have been performed under the transesophageal echocardiography (TEE) guidance. Before and 24 h after TAVI, all patients underwent transthoracic echocardiography (TTE) and mitral inflow velocities with pulsed-wave (PW) Doppler including early filling wave (E), late diastolic filling wave (A), and E/A ratio were obtained. LV diastolic function was also explored by pulsed tissue Doppler imaging (TDI). Early (E’) and late (A’) diastolic annular velocities, E’/A’ ratio and E/E’ ratio were obtained. In addition, during the procedure before and minutes after the valve implantation, the left atrial appendage-peak antegrade flow velocity (LAA-PAFV) was measured and recorded with TEE.
Results: Compared with baseline, the mean mitral E, septal E’ and E’/A’ ratio increased significantly after TAVI. In addition, the LAA-PAFV increased significantly within minutes of TAVI (32.45 ± 10.7 cm/s vs. 47.6 ± 12.6 cm/s, p < 0.001).
Conclusions: TAVI improves LV diastolic function and LA performance immediately
Impact of transcatheter aortic valve implantation in patients with reduced ejection fraction
Background: Aortic stenosis increases with age. According to guidelines, left ventricular systolic dysfunction is an indication for aortic valve replacement, even in asymptomatic patients. There is no clear data on the application of transcatheter aortic valve implantation (TAVI), which is a method showing continuous improvement in recent years, in patients with reduced ejection fraction (REF) having a poor prognosis for surgical aortic valve replacement. We therefore aimed to investigate the effect of TAVI on left ventricular ejection fraction (LVEF) and also its efficacy and safety in patients with REF. Methods and results: The study included 104 patients who underwent transfemoral TAVI in our clinic. The patients were divided into two groups: LVEF ≤ 45% (REF group, n = 28) and LVEF > 45% (preserved ejection fraction [PEF] group, n = 76). Follow-up measurements were performed at baseline, discharge, 1st, 6th and 12th months. No statistical difference was found between the groups with respect to complications and mortality rates. A statistically significant difference was detected in LVEF after TAVI, either in all patients (53.9 ± 14.6, 57.0 ± 11.4, 59.4 ± 8.4, 60.4 ± 6.8, 63.2 ± 3.9, respectively, at baseline, discharge, 1st, 6th and 12th months, p < 0.001) or in the groups separately. A statistically significant increase in LVEF (p < 0.001) was determined at discharge, 1st, 6th and 12th months, whereas LVEF increased in all follow-ups of the PEF group, however this elevation reached a statistical significance only at the 1st month (p = 0.04). Conclusions: Our study has shown the positive effect of TAVI on LVEF and its effective and safe applicability in patients with REF.
Neck muscle mass index as a predictor of post laryngectomy wound complications
Objective:
We investigated the relationship between paravertebral muscle cross-sectional area (PVM CSA) at the third vertebra (C3) level using computerized tomography (CT) neck images and its relationship with complications after total laryngectomy.
Design:
Retrospective analysis of 60 advanced laryngeal cancer patients who underwent total laryngectomy was performed. The cross-sectional areas of paravertebral neck muscles using neck CT at C3 level images obtained preoperatively were analyzed.
Results:
A significant difference in PVM CSA between complication and no complication groups, F(1, 53 = 4.319, P = .043), was identified by ANCOVA. There were no significant differences in between-subject effects: T-stage (F = 1.652, P = .204), body mass index (F = 0.889, P = .35), albumin (F = .359, P = .552), age (F = 1.623 P = .208), and smoking (F = 4.319, P = .41).
Conclusion:
The PVM CSA measured at C3 level on pretreatment CT may help identify patients at higher risk of postoperative wound complications after total laryngectomy and who may particularly benefit from preoperative optimization of nutritional status
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