Layered clay/epoxy nanocomposites: Thermomechanical, flame retardancy, and optical properties

In this study, layered clay/polymer nano-composites were developed based on epoxy resins and montmorillonite as the nanoplatelet reinforcement. Clay particles were treated with hexadecyltrimethylammonium chloride (HTCA) through an ion exchange reaction. In this way, Na+ interlay er cations of the clay is exchanged with onium cation of the surfactant that turns the hydrophilic clays (MMT) to organophilic (OMMT) characteristics. Thermal analysis results revealed that the glass transition temperature (Tg) and the dynamic mechanical properties including the storage and loss modulus of the neat epoxy resin increases by the incorporation of clay particles. It was also found that flame resistance of the polymer is improved by the addition of the clay particles

Long Memory in the Volatility of Selected Cryptocurrencies: Bitcoin, Ethereum and Ripple

This paper examines the volatility of cryptocurrencies, with particular attention to their potential long memory properties. Using daily data for the three major cryptocurrencies, namely Ripple, Ethereum, and Bitcoin, we test for the long memory property using, Rescaled Range Statistics (R/S), Gaussian Semi Parametric (GSP) and the Geweke and Porter-Hudak (GPH) Model Method. Our findings show that squared returns of three cryptocurrencies have a significant long memory, supporting the use of fractional Generalized Auto Regressive Conditional Heteroscedasticity (GARCH) extensions as suitable modelling technique. Our findings indicate that the Hyperbolic GARCH (HYGARCH) model appears to be the best fitted model for Bitcoin. On the other hand, the Fractional Integrated GARCH (FIGARCH) model with skewed student distribution produces better estimations for Ethereum. Finally, FIGARCH model with student distribution appears to give a good fit for Ripple return. Based on Kupieck's tests for Value at Risk (VaR) back-testing and expected shortfalls we can conclude that our models perform correctly in most of the cases for both the negative and positive returns

Paradoxal aspects in circumcision

[No abstract available

The evaluation of children with monosymptomatic nocturnal enuresis for attention deficit and hyperactivity disorder

WOS: 000307300500010PubMed: 22122653Objective. Monosymptomatic nocturnal enuresis (MNE) and attention deficit and hyperactivity disorder (ADHD) are multifactorial disorders and biological, social, and psychological factors may play significant roles in the development of both. Children with enuresis display a higher prevalence of ADHD compared to the normal population. This study aimed to evaluate the relationship between MNE and ADHD. Methods. A total of 64 children between the ages of 6 and 13 years who were referred due to primary MNE, their parents, and 42 healthy control cases, were evaluated in terms of attention deficit and hyperactivity by a child psychiatrist using the DSM-IV-2000-TR diagnosic scale. Results. Of the children with enuresis, 17 had predominantly inattentive type (26.6%), nine had predominantly hyperactive-impulsive type (14.1%), and eight had combined type (12.5%). In the control group, two cases had predominantly inattentive type (4.8%), two cases had predominantly hyperactive-impulsive type (4.8%), and one had combined type (2.4%). Conclusions. The prevalence of ADHD is higher in children with MNE compared to the normal population. As attention deficit may also negatively effect the treatment of enuresis, children with MNE should be evaluated in terms of attention deficit and those with positive symptoms should be provided with psychosocial support

Foreign body aspiration with the right upper lobe atelectasis

Yabancı cisim aspirasyonu ( YCA) çocuklarda sık görülen ve hayatı tehdit eden komplikasyonlara neden olabilen acil bir durumdur. YCA genellikle 3 yaş altı çocuklarda sık görülür.YCA; trakeal tam tıkanma veya perforasyon, larinks ödemi, bronkospazm, endobro nsiyal kanama, pnömotoraks, kardiyak arrest gibi ciddi sorunlara yol açabilirken, tanı konulamamış, geç dönemde ise genellikle pnömoni, bronşit atelektazi, bronşiektazi, bronş strüktürü veya bronşiyal astım gibi tanılarla karsımıza çıkabilirler. Bizim 13 a ylık olgumuzda YCAa bağlı sağ üst lob akciğer atelektazisi gelişmiş ve solunum sıkıntısına neden olmuştu. Bu olgu yabancı cisim aspirasyonunun beklenmedik bir şekilde sağ üst lob atelektazisine neden olması yönüyle sunuldu.Foreign body aspiration (FBA) is common in children and is an emergency situation that can cause life -threatening complications. FBA is usually common in children under 3 years of age. FBAs early can be lead to serious problems such as cardiac arrest complete tracheal obstruction or perforation, laryngeal edema, bronchospasm, endobronchial bleeding, pneumothorax. Undiagnosed late period, we encountered with diagnoses such as usually pneumonia, bronchitis, atelectasis, bronchiectasis, bronchial structure asthma or bronchial. The presen t case of 13 -month male infant with FBA, lung atelectasis of the right upper lobe and respiratory distress had been developed. This case is reported to emphasize FBA can cause unexpected aspect of the right upper lobe atelectasis

A Case of Bronchogenic Cyst Mimicking Foreign Body Aspiration

WOS: 000330470200013PubMed: 23823265Bronchogenic cysts (BCs) can be life threatening if they compress vital structures in infants and small children. In particular, subcarinal cysts can be life-threatening and compromise the airways. In infants, the initial presentation may be respiratory distress. We report a case of mediastinal cystic mass compressing the main left bronchus. The case was an 18-month-old boy who had been admitted with acute respiratory distress. Chest x-ray showed overdistension of the left lung and a mediastinal shift. Foreign body aspiration was diagnosed. Magnetic resonance imaging was performed, which has shown a mediastinal cystic mass; therefore, the patient underwent thoracotomy. Surgical intervention revealed a subcarinal extrapulmonary BC that compresses the left main bronchus. The diagnosis of BC was confirmed with pathological investigation. In this report, we present a case of BC with the emphasis on the differential diagnosis with foreign body aspiration

KOROZİV ÖZOFAGUS YANIĞINDA KİTOZAN VE EPİDERMAL BÜYÜME FAKTÖRÜNÜN ETKİLERİ

GİRİŞ: Koroziv özofagus yanıkları, özellikle çocukluk döneminde, kostik madde alımı sonucu oluşmakta ve sıklıkla özofagusta daralmaya neden olan fibrozis ile sonuçlanmaktadır. Bu nedenle özofagus yanıkları sonrası gelişen fibrozisin azaltılması hayati öneme sahiptir. Yara iyileşmesi amacıyla topikal bir ajan olarak kullanılan kitozanın olumlu etkisi bilinmekle birlikte, etki mekanizması halen tam açık değildir. Bu çalışmada özofagus yanığı oluşturulan deney hayvanı modelinde kitozan ve epidermal büyüme faktörünün, tedavi ve fibrozis gelişimi üzerine etkilerinin araştırılması amaçlanmıştır. MATERYAL-METOD: Wistar-Albino türü sıçanlar; intakt kontrol grubu, özofagus yanığı oluşturulan grup, yanık+kitozan verilen grup ve yanık+kitozan+ epidermal büyüme faktörü verilen grup olmak üzere, 4 gruba ayrıldı. 28.günde anestezi altında yara bölgesini içeren özofagus doku parçaları elde edildi. Dokular; ışık, elektron mikroskopik ve biyokimyasal incelemeler için uygun yöntemlerle hazırlandı. BULGULAR:Yanık oluşturulan grupta, epitelde proliferasyon, enflamatuvar hücreler, lamina propriyada aktif fibroblastlar ve kollajen liflerde belirgin bir artışın varlığı dikkati çekti. Yanık+kitozan uygulanan grupta epitelin belirgin şekilde geliştiği, hücrelerde normal yapının korunduğu izlenmekle birlikte, bazı alanlarda epitelde yara iyileşme alanları ve enflamatuvar hücreler izlenmekteydi. Lamina propriyada, yanık grubuna benzemekle birlikte, kollajen lif demetlerinin yoğunluğunda bir azalmanın varlığı ilgi çekiciydi. Yanık+kitozan+ epidermal büyüme faktörü verilen grupta epitel gelişimi ve hücrelerin ince yapısı çoğunlukla normaldi

High hydrostatic pressure assisted extraction of pectin from sugar beet pulp

This study aimed to investigate the effect of high hydrostatic pressure assisted extraction (HHPE) (250, 350 and 450 MPa at 40 degrees C for 5 min with/without acid addition) of pectin from sugar beet pulp and compare its properties with pectin obtained from conventional extraction (CE). Degree of esterification (DE), galacturonic acid (Gal-A) content, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) relaxometry experiments were performed on the obtained pectin powder. HHPE (12.23 +/- 0.13%) doubled extraction yield compared to CE (6.43 +/- 0.07%). Also, HHPE and acid addition were found to have a synergetic effect on the extraction. HHPE resulted in degradations in the polymer structure and reduced Gal-A content and DE. Pectin extracted with both methods was classified as low methoxyl pectin (LMP). According to the NMR Relaxometry results, HHPE decreased water holding capacity (WHC). In brief, HHP was shown to increase the pectin extraction yield and no changes in viscosity were observed at the concentrations studied (2 g/L)

A case of bronchogenic cyst admitted by recurrent pulmonary infection

Bronkojenik kist embriyonik foregutun anormal tomurcu klanması sonucu gelişen ender rastlanan bir bozukluktur. Bazen doğumda solunum sıkıntısına neden olurken bazen de erişkin döneme kadar asemptomatik kalabilir. Basıya bağlı klinik bulgular yenidoğan ve süt çocukluğu dönemindeki en önemli yakınmalardır. Burada tekrarlayan akciğer enfeksiyonu nedeniyle izlenen 9 aylık bronkojenik kist olgusu sunu lmuştur. Tekrarlayan akciğer enfeksiyonu etiyolojisinde bro nkojenik kistin de göz önünde bulundurulması gerektiğini vurgulama k istedik.Bronchogenic cyst is a rare disorder that result from abno rmal budding of embrionic foregut. While it sometimes ca uses to respiratory distress at birth, it may also remain asymptomatic until adulthood. Clinical symptoms due to compression are mo st frequent complaints in neonatal and infancy period. Herein, a nine month old case of bronchogenic cyst followed for recurrent pulmonary infections was presented. We would like to emphasize that the bronchogenic cyst should be considered on etiology of r ecurrent pulmonary infections