Determining the Efficiency of Different Preoperative Difficult Intubation Tests on Patients Undergoing Caesarean Section

Background: Pregnancy-induced anatomical and physiological changes in the airway make airway management difficult in obstetric patients; thus, preoperative evaluation of the airway is important for obstetric patients. Aims: To determine the effectiveness of the modified Mallampati test; the interincisor, sternomental and thyromental distances and the upper limb bite test. The second aim was to assess the effectiveness of the combination of the upper limb bite test with the other tests in obstetric patients. Study Design: Cross-sectional study. Methods: Pregnant women (n=250) scheduled for caesarean section were analysed. The patients' ages, heights and weights were collected. Preoperative airway evaluation was done by using a modified version of the Mallampati test. The interincisor, sternomental and thyromental distances were measured, and the upper limb bite test was performed. The laryngoscopy difficulty was evaluated by using Cormack-Lehane classification. Results: No statistically significant differences were found between groups in age, height or weight (p>0.05). The modified Mallampati test and interincisor, sternomental and thyromental distances revealed a lower number of easy intubations than that determined by the Cormack-Lehane classification and a higher number of difficult intubations than the actual number of cases (p<0.05). The sensitivity and specificity of the modified Mallampati test, the upper limb bite test, the interincisor distance test and the sternomental and thyromental distance tests were found to be 73.08, 57.69, 84.62, 80.77 and 88.46 and 90.62, 99.11, 83.04, 84.37 and 87.05, respectively. When the combinations were examined, the sensitivity and specificity of the combination of the upper limb bite test with the modified Mallampati test were found to be 57.69 and 100, respectively. When the upper limb bite test was combined with the interincisor distance, the sensitivity and specificity were 46.15 and 100, respectively. We found a sensitivity and specificity of 93.75 and 95.30, respectively, for the combination of the upper limb bite test with the thyromental distance test. The sensitivity and specificity of the combination of the upper limb bite test with the modified Mallampati test and interincisor distance test were found to be 46.15 and 100, respectively. For combination of all the tests, the sensitivity and specificity was 42.31 and 100, respectively. Conclusion: When all combinations are evaluated in the decision of difficult intubation, the combination of the upper limb bite test and thyromental distance test is superior to the use of other methods alone to predict difficult intubation in pregnant women

A distance-independent basal area growth model for oriental spruce (Picea orientalis (l.) Link) growing in mixture with oriental beech (Fagus orientalis Lipsky) in the Artvin region, North-East Turkey

In this study, we developed an individual tree basal area growth model for oriental spruce (Picea orientalis (L.) Link) growing in mixture with oriental beech (Fagus orientalis Lipsky) in the Artvin, Turkey. In our modeling approach, the basal area growth variables were divided into 4 main groups, which included size, competition, site and mixture. The parameters of these variables were biologically consistent with general growth trends of forest growth models and we found them each to be statistically significant at the probability level of 0.05. Our model explained 62.4% of the basal area growth variation of oriental spruce with a standard error of 0.836 cm2. Furthermore, we found that the absolute and relative (%) biases and the root mean square error (RMSE and RMSE%) of the 5 year basal area growth of oriental spruce were 0.00823 cm2, 0.1353%, 0.8234 cm2, 33.39% respectively. We evaluated this model by plotting the biases with respect to considerable regressor variables. These graphical analyses of the model biases showed no meaningful and evident trend of bias values along with these independent variables. Our model provides a clear frame of reference for understanding about the individual tree basal area growth patterns of for oriental spruce growing in mixture with oriental beech. This model further shows that the parameter of the mixture proportion (BP) for oriental beech trees in the mixture model component was positive, indicating that basal area growth of spruce increases as the proportion of beech in the forest mixture goes up if other variables remain constant. This positive effect of admixture may be due to the facilitation process occurring in oriental spruce stands mixed with beech trees. The facilitation pattern of beech trees in mixing spruce stands suggests that poor or degraded forest sites may be improved by mixing beech trees for forest areas in this region

Channel Model of Molecular Communication via Diffusion in a Vessel-like Environment Considering a Partially Covering Receiver

By considering potential health problems that a fully covering receiver may cause in vessel-like environments, the implementation of a partially covering receiver is needed. To this end, distribution of hitting location of messenger molecules (MM) is analyzed within the context of molecular communication via diffusion with the aim of channel modeling. The distribution of these MMs for a fully covering receiver is analyzed in two parts: angular and radial dimensions. For the angular distribution analysis, the receiver is divided into 180 slices to analyze the mean, standard deviation, and coefficient of variation of these slices. For the axial distance distribution analysis, Kolmogorov- Smirnov test is applied for different significance levels. Also, two different implementations of the reflection from the vessel surface (i.e., rollback and elastic reflection) are compared and mathematical representation of elastic reflection is given. The results show that MMs have tendency to spread uniformly beyond a certain ratio of the distance to the vessel radius. By utilizing the uniformity, we propose a channel model for the partially covering receiver in vessel-like environments and validate the proposed model by simulations

Diameter distribution modelling for pure oriental spruce

Ormanların meşcere yapıları, bu meşcerelerin günümüz ve gelecekteki çap dağılımlarının ortaya konulması ile tanımlanmaktadır. Meşcerelerin çap dağılımının modellenmesi ise, meşcerelerden elde edilebilecek ürün çeşitleri tahmini olanağı sağlaması bakımından da ormancılık planlanmasında karar verme sürecinde değerli bir bilgi olmaktadır. Bu çalışmada, Artvin yöresi saf Doğu Ladini (Picea orientalis (L.) Link) meşcerelerinden alınan 45 adet örnek alan verilerine bağlı olarak, çap dağılımlarının modellemede başarıları bakımından 2 parametreli Weibull, 3 parametreli Weibull, 2 parametreli Gamma, 3 parametreli Gamma, Beta, 2 parametreli Lognormal, 3 parametreli Lognormal, Normal, Johnson SB olasılıklı yoğunluk fonksiyonları karşılaştırılmıştır. Rennolds vd. (1988) tarafından geliştirilen hata indeksi “error index” değerlerine bağlı olarak yapılan bu karşılaştırmada, farklı çap dağılımlarını temsil etmede en başarılı fonksiyon olarak Johnson SB fonksiyonu belirlenmiştir. Daha sonra ise; Beta, 2 parametreli Weibull, Normal, 3 parametreli Gamma, 3 parametreli Weibull, 3 parametreli Lognormal, 2 parametreli Gamma, 2 parametreli Lognormal fonksiyonları gelmektedir. 4 parametreli Johnson SB fonksiyonu, farklı yapıdaki çap dağılımlarını temsil etmede kabiliyetleri ve esneklikleri oldukça yüksek olup, farklı çap dağılımlarını modelleme oldukça başarılı bir fonksiyondur.Stand dynamics were characterized by displaying actual and predicted diameter distribution. The modeling diameter distribution is valuable information to can be used to forecast the range of products, which might be expected from a stand in forest management. In this study, some probability density functions, Weibull with two parameters, Weibull with three parameters, Gamma with two parameters, Gamma with three parameters, Beta, Lognormal with two parameters, Lognormal with three parameters, Normal, Johnson SB, were compared based on describing different diameter distribution for oriental spruce (Picea orientalis (L.) Link) stands in Artvin province. The results based on error index of Rennolds et al. (1988) showed that Johnson SB function is the best successful function to describe diameter distributions, and other functions were ranged in order of merit, Beta, Weibull with two parameters, Normal, Gamma with three parameters, Weibull with three parameters, Lognormal with three parameters, Gamma with two parameters, Lognormal with two parameters. The Johnson SB with four parameters is flexible and capable to describe different diameter distributions, and so this function was successfully used to model diameter distributions

Stabilizing constant diagonal controllers for TITO systems

Proses kontrolün ilk ve en önemli amacı sistemi kararlı kılmaktır, performans üzerine yapılacak her eylem bu temel koşul sağlandığı müddetçe bir anlam taşır. Kontrolör tasarımında kullanılan yöntemlerden biri sistemi kararlı kılacak tüm kontrolörleri bulmak ve ardından, tasarımdaki diğer beklentileri sağlamak üzere, bu sınıf içinden uygun bir kontrolörde karar kılmaktır. Bu hedef doğrultusunda yapılanlar şu özellikleri de barındırmalıdır ki, iyi bir kontrolör tasarım sürecinden söz edilebilsin. Kontrolör kırılgan olmamalıdır, yani kontrolör de parametre değişimlerine karşı sistemin kararlılığını ve mümkünse performansını zedelememelidir. Kontrolörün düşük mertebeden olması, parametre ayarlama sürecinde büyük kolaylıklar sağlar, zira ne kadar az parametre o kadar basit bir tasarım süreci demektir. Öte yandan pratik anlamı dolayısıyla da az parametre, ya da düşük mertebe endüstride görev alan uygulamacılar için problemlerin daha hızlı çözülmesi anlamına gelir. Bu çalışmada çok değişkenli kontrol yapıları arasında önemli bir yer tutan karakteristik değerler ve karakteristik değer eğrileri ele alınmış, rasyonel polinomlar cisminde indirgenebilir olan karakteristik denklemler için karakteristik değerlerin reel ekseni kesim noktaları ve bu noktalar civarındaki davranışları üzerinde durulmuştur. Zira bu değerler çok girişli çok çıkışlı sistemleri kararlı kılan kontrolörlerin bulunmasında ya da verilen bir kazanç değeri için kararlılığın analiz edilmesinde hızlı hesaplanabilirlikleri yönünden önem arz etmektedirler. Bu çalışma kapsamında iki girişli iki çıkışlı (TITO) sistemleri kararlı kılan sabit köşegen kontrolörler üzerinde durulmuş, karakteristik değer eğrilerinin reel ekseni kestikleri yerler ve eğrilerin bu noktalardaki geçiş yönlerinden hareket ederek hızlı bir algoritma geliştirilmiş ve bu tür sistemleri kararlı kılan kontrolörler örnek sistem üzerinde sınanarak hesaplanmıştır. Anahtar Kelimeler: Bilgisayar cebri, blok diyagram indirgeme, PID kontrol, parametre uzayı yaklaşımı, karakteristik değer eğrileri.A control system is an interconnection of compo-nents to perform certain tasks and to generate desired output signal, when it is driven by the input signal. In contrast to an open-loop system, a closed-loop control system uses sensors to measure the actual output to adjust the input in order to achieve desired output. Most industrial control systems are no longer single-input and single-output (SISO) but multi-input and multi-output (MIMO) systems with a high coupling between the channels. In the design of all dynamical systems stability is the most important property. When a dynamic system is described by its input-output relationship such as a transfer function, the system is stable if it generates bounded outputs for any bounded inputs; bounded-input bounded-output (BIBO) stability. For a linear, time-invariant system modeled by a transfer function matrix, the BIBO stability is guaranteed if and only if all the poles of the transfer function matrix are in the open-left-half complex plane. A reasonable approach to controller design is to find the set of all stabilizing compensators and then using a member of this set to satisfy further design criteria. A complete parameterization of all stabilizing controllers for a given system was suggested by Youla. An important disadvantage of this parameterization is that the order of the controller cannot be fixed. As a result, the order of the controller tends to be quite high most of the time. Therefore, in the last few years computation of all stabilizing controllers of a given order is examined by several researchers. It is a common fact that it is more difficult to design controllers for MIMO systems because there are usually interactions between different control loops. To overcome this difficulty decentralized controllers are considered which have fewer tuning parameters compared to general multivariable controllers. For example, decentralized PID (P: proportional, I: integral, D: derivative)  controllers are widely used in process control due their simplicity and facility in working in case of actuator and/or sensor failure because it is relatively easy to tune manually as only one loop is directly affected by the failure. If a MIMO system described by a  transfer-function matrix G(s) is diagonal dominant over the bandwidth of interest, or there exists an input compensator matrix C(s) to achieve diagonal dominance, then the stability and time domain behavior of the system can be inferred from the diagonal elements of G(s)C(s). The relative gain array, the (inverse) Nyquist array approach, the block Nyquist array method, the Perron-Frobenius scaling procedure and the characteristic locus method are among the analysis and design methods to reduce the interaction in a multivariable system. However, these approaches do not provide the set of all stabilizing controllers. Generalizing the Nyquist stability criterion for MIMO case is particularly important because plotting the characteristic values of the open-loop transfer function enables us to check the stability of the closed-loop system for a gain parameter. A stable characteristic polynomial, becomes unstable if and only if at least one root crosses the imaginary axis. The parameter values of the root crossing form the stability boundaries in the parameter space, which can be classified into three cases: the real root boundary, where a root crosses the imaginary axis at the origin, the infinite root boundary, where a root leaves the left half plane at infinity and the complex root boundary, where a pair of conjugate complex roots crosses the imaginary axes. These stability boundaries separate regions in which the number of closed loop system unstable poles does not change in parameter space.The main objective of this work is to develop an efficient and fast algorithm that can be used in finding all stabilizing constant controllers of diag(k,k)-type for TITO processes. Recall that a TITO system has two characteristic values that are in the field of rational functions, if the characteristic equation is reducible in this field. Hence Nyquist stability criterion can be applied to both of the characteristic values in order to determine the conditions for stability.  Recall that the generalized Nyquist theorem requires that the net sum of encirclements of the point -1 by the characteristic values equal to the number of open-loop unstable poles of the system. Hence, it is of special importance to determine where the characteristic locus intersects with the real axis, i.e. where the imaginary part of, is zero. The direction of these crossings is also important, because the net count of crossings at an intersection point will indicate whether there are closed-loop poles to cross the imaginary axis.  Keywords: Computer Algebra, block diagram reduction, PID control, parameter space approach, characteristic value plots

Endoanal ultrasonografi ile perianal atnalı fistül tespiti: Video sunum

Today, the horseshoe fistulas are counted among the most difficultly managed perianal fistula types. This entity, which is regarded as one of a complex fistula type, affects the ischioanal fossa. Its treatment is more costly and the optimal surgical intervention required is more complex. Since it can affect more than one anatomical structure, chance of treatment failure, perioperative and postoperative complication rates and recurrence rates increase. Especially insufficient preoperative assessment leads in most cases to devastating outcomes for both the physician and the patient. Horseshoe fistulas can be diagnosed easily with magnetic resonance imaging, which is a common modality used in evaluating perianal fistulas. However, due to the high cost and dependance on an experienced radiologist for interpretation in common practice, endoanal ultrasonography (USG) has started to gain popularity. Ability of assessing the perianal anatomy and especially the sphincter complex properly just prior to surgery in operating theatre comprise the most prominent advantages of endoanal USG. In this video presentation, we aimed to show the endoanal USG images of a horseshoe fistula tract following the injection of hydrogen peroxid solution with a branule in the perianal fistula tract of a patient with a history of Crohn’s disease.Günümüzde yönetimi en zor olan perianal fistül çeşitlerinden biri de atnalı fistüllerdir. Kompleks fistüller kategorisinde değerlendirilen bu hastalık işioanal fossayı etkilemekte olup tedavisi daha maliyetli ve gereken optimal cerrahi girişimi daha komplekstir. Birden fazla anatomik yapıyı etkileyebilmesi nedeni ile tedavi başarısızlığı, peroperatif ve postoperatif komplikasyon oranlarının artması, rekürrens oranının yüksek olması ve özellikle yetersiz preoperatif değerlendirme sonucu hem hekim hem de hasta yönünden ciddi negatif sonuçlar doğabilmektedir. Perianal fistüllerde sık kullanılan bir modalite olan MR ile atnalı fistüllerin tanısı rahatlıkla konabilmektedir. Ancak maliyetin yüksek olması ve çoğunlukla yorum için bir radyoloğa ihtiyaç duyulması nedeni ile endoanal ultrasonografi (USG) son zamanlarda klinik uygulamaya daha çok girmeye başlamıştır. Endoanal USG’nin en önemli avantajları arasında ameliyat masasında eş zamanlı perianal bölge anatomisinin ve özellikle sfinkterlerin optimal şekilde değerlendirilebilmesi söylenebilir. Bu video prezentasyonda crohn hastalığı öyküsü olan bir hastada atnalı fistül traktının intraket ile oksijenli su enjeksiyonunu takiben endoanal USG görüntüsünün paylaşılması amaçlanmıştır

Simple vaginal trachelectomy for early stage cervical cancer: A tertiary cancer center experience

Objectives: Less radical fertility sparing procedures have been introduced to reduce morbidity and adverse obstetric outcome in cervical cancer. Our objective was to describe oncological and obstetric outcomes of women with early-stage cervical cancer who underwent a simple vaginal trachelectomy (SVT). Material and methods: From 01/2013 to 05/2017, 14 women underwent SVT preceded by laparoscopic pelvic lymph node dissection. Results: Patients’ median age was 32 years and all of them were nulliparous. Histology included squamous cell carcinoma and adenocarcinoma in 12 (85.7%) and 2 (14.3%) patients, respectively. Three patients had stage 1A1 with lymphovascular space invasion, 4 1A2 and 7 1B1. After obtaining final histopathology, one patient underwent radical hysterectomy due to positive surgical margin and excluded from analysis. None of the patients had lymph node metastasis. None of the 13 patients developed a recurrence within a median follow-up of 27 (6–56) months. Seven patients have conceived: 4 were term deliveries, 2 were late preterm deliveries and 1 was spontaneous abortion. Conclusions: SVT in well selected early-stage cervical cancer patients seems to be a safe treatment option with excellent oncologic outcome, preserving reproductive function. Literature data will need to be confirmed in large prospective series

Medikal tedaviye yanıtsız pruritus ani’li hastada perianal metilen mavisi enjeksiyonu: Video prezentasyon

Pruritus Ani is one of the common dermatological diseases of the perianal skin in the general population. This disease affects 1%-5% of the society. It presents as itching and burning in the perianal area. Men are affected four times more than women, and it is diagnosed most commonly in the fourth to sixth decades of life. This disease, which is most commonly seen as idiopathic, may develop secondary to infectious factors such as staph. aureus, candida albicans, thinning of the perianal skin due to the long-time use of topical steroids, dermatological diseases such as psoriasis or malignancies. The treatment of the underlying disease constitutes the main treatment for the secondary disease, and in the idiopathic disease, a wide range of treatment methods are used, from conservative treatments to various medical treatments and injection of various substances into the perianal area. In this video presentation, it is aimed to present the application of methylene blue injection to the perianal skin in a patient with idiopathic pruritus ani unresponsive to medical treatment.Pruritus ani toplumda sık karşılaşılan perianal bölgenin dermatolojik hastalıklarındandır. Bu hastalık toplumun %1-%5’ini etkilemektedir. Perianal bölgede kaşıntı ve yanma olarak prezente olur. Erkeklerde kadınlara oranla dört kat fazla görülür ve en sık görülme yaşı dördüncü ve altıncı dekatlar arasındadır. En sık idiopatik olarak görülen bu hastalık staf. aureus, candida albicans gibi enfeksiyöz etkenlere, uzun süre steroidli topikal ajanların kullanımına bağlı perianal bölge cildinin incelmesine, psoriasis gibi dermatolojik hastalıklara veya malignitelere sekonder olarak gelişebilmektedir. Sekonder hastalıkta altta yatan hastalığın tedavisi esas tedaviyi teşkil etmekte olup idiopatik hastalıkta ise konservatif tedavilerden çeşitli medikal tedavilere ve çeşitli maddelerin perianal bölgeye enjeksiyonuna kadar geniş bir yelpazede bir çok tedavi yöntemi uygulanmaktadır. Bu video prezentasyonda medikal tedaviye yantısız idiopatik pruritus anili bir hastada perianal bölgeye metilen mavisi enjeksiyonu uygulamasının sunulması amaçlanmıştır

What influences women’s contraceptive choice? A cross-sectional study from Turkey

Objectives: In our study, we tried to investigate the determinants of women’s choices about contraception with the aim of discovering whether or not there is a difference in their preferences before and after consultation with a gynaecologist. Material and methods: A total of 1058 women were enrolled. They were given detailed information regarding contraception and contraceptive methods. Subsequently, a survey which was made of 21 questions was administered. Results: Contraceptive counselling significantly changed the contraceptive choice of women. However, influences from social media and friends, their partners and religious belief affected their contraceptive choices. Significant differences in contraceptive choice were observed when women were categorized according to their marital status, education level, household income, age, and number of children. Conclusions: Although contraceptive counselling influenced Turkish women’s choices, there were still other determinants like social media and input from outside sources such as clerics and husbands, which should be overcome