bluuebunny/crossref_metadata_2025 huggingface dataset:
Mittendrin statt nur dabei
Authors: Schlote Elke , Klug Daniel , Neumann-Braun Klaus
Published: August 2020

In diesem Artikel wird der digitale Wandel an Schulen zum Ausgangspunkt genommen, um die Konsequenzen des Einsatzes von digitalen Lernwerkzeugen für die Interaktionsstrukturen im schulischen Unterricht aus einer praxeologischen Perspektive zu reflektieren. Es wird für die Entwicklung von digitalen Lernwerkzeugen argumentiert, welche Partizipation und Kollaboration im Unterricht fördern und das strukturierende Lehrerhandeln unterstützen. Als Fallbeispiel dient die Web-App TRAVIS GO und ihr Entwicklungsprozess, in welchen Lehrpersonen aus den Sekundarstufen I und II als Co-Researcher eingebunden waren. TRAVIS GO ist eine App zur kollaborativen Re- und Dekonstruktion von audiovisuellen Medienprodukten. Im didaktischen Design von TRAVIS GO wurden die Anforderungen an problemlösendes, forschendes Lernen und kooperatives Arbeiten erfüllt und die Möglichkeit zum strukturierenden Lehrerhandeln gegeben. TRAVIS GO wird mit Fokus auf die programmseitig angebotenen Möglichkeiten zur Partizipation erstmals systematisch beschrieben und mit den Erfahrungen von Lehrpersonen im Unterrichtseinsatz zusammengebracht, welche im Forschungs- und Entwicklungsprojekt im Rahmen einer empirischen Bildungsforschung gewonnen wurden.
Lehren und Lernen mit und über Medien in Kooperation von Schule, Hochschule und Museen
Authors: Autenrieth Daniel , Baumbusch Claudia , Marquardt Anja
Published: August 2020

Der Beitrag stellt das Entwicklungsprojekt ‹Reuchlin digital› (RD) am Museum Johannes Reuchlin (MJR) in Pforzheim vor, welches im Schnittfeld von kultureller Bildung (in schulischen und ausserschulischen Kontexten), Medienpädagogik und der Lehramtsausbildung verortet ist. Johannes Reuchlin (Humanist und Zeitgenosse der Medienrevolution des Buchdrucks) setzte sich für Toleranz und die Erkundung alles Fremden ein. Seine Botschaften stehen leitmotivisch über dem Projekt. RD ist als praxisbezogenes Entwicklungs- und Modellprojekt mit evaluativen Elementen angelegt. Der Schwerpunkt des Beitrags soll auf der Darstellung theoretisch-konzeptioneller Überlegungen sowie wichtiger Zwischenergebnisse liegen. RD wurde vom Kulturamt Pforzheim initiiert (Förderpartner: Innovationsfonds BW, Arbeitsstelle literarische Museen BW) mit Kooperationspartnern verschiedener Institutionen (PH Ludwigsburg, Medien- und Filmgesellschaft BW, Schulen verschiedener Schularten). Ein zentrales Anliegen von RD ist es, durch die aktiv-produktive, kreative und kritisch-reflexive Nutzung digitaler Medien und insbesondere durch die Vermittlung visueller, auditiver und audiovisueller Ausdrucksformen neue Lernwege zu eröffnen und einen ausserschulischen Lernort unter Einbezug kultureller, ästhetischer und medialer Aspekte handlungsorientiert zu erschliessen.
Deutungshoheiten: Digitalisierung und Bildung in Programmatiken und Förderrichtlinien Deutschlands und der EU
Authors: Altenrath Maike , Helbig Christian , Hofhues Sandra
Published: August 2020

Der vorliegende Beitrag befasst sich mit diskurs- und machtpolitisch hervorgerufenen Deutungshoheiten in Bezug auf Forschung zu und über Digitalisierung und Bildung in Programmatiken und Förderrichtlinien Deutschlands und der EU. Er gründet auf der Annahme, dass Forschungs- und Wissenschaftssysteme seit geraumer Zeit in enger Abhängigkeit zu Förderprogrammen stehen, welche auf unterschiedlichen politischen Ebenen als so genannte Förderinstrumente diverser Bildungsbereiche und der Wissenschaft selbst fungieren (sollen). Bei empirischer Betrachtung werden Deutungshoheiten infolge dieser Hinwendung zu und gleichzeitigen Abwendung von Begriffen und Konzepten sichtbar – nicht nur im Zusammenhang mit Diskursen um Digitalisierung und Bildung. Folge sind die (Über-)Betonung einzelner Konzepte und die zurückhaltende Repräsentation anderer, was für die Medienpädagogik qualifikatorische Engfassungen bedeutet, die auf empirischer Basis sowie vor dem Hintergrund präsenter Konzepte zu zeigen sind.
Experience of using a combination mucoactive drug during chemotherapy in patients with MDR/XDR tuberculosis
Authors: Myshkova E. P. , Sklyuev S. V. , Zhukova E. M. , Krasnov D. V. , Petrenko T. I.
Published: August 2020

The objective: to evaluate the effectiveness of the medication containing a 7% NaCl solution and 0.1% sodium hyaluronate in patients with destructive pulmonary tuberculosis and multiple/extensive drug resistance (MDR/XDR) and inflammatory changes in the tracheobronchial tree. Subjects and methods. A prospective randomized controlled study was carried out, which included 69 patients with destructive pulmonary tuberculosis and MDR/XDR and respiratory complaints and changes in the tracheobronchial tree detected by fibrobronchoscopy. All patients underwent a complete clinical and functional examination, and by analyzing the questionnaires, the mMRC dyspnea index was calculated, the CAT test was performed, and the response to treatment was assessed using the Likert scale. The patients were randomly divided into two groups. The main group included 30 patients; in addition to anti-tuberculosis therapy, through a nebulizer, they received inhalation with the solution containing 7% NaCl and 0.1% sodium hyaluronate, 5 ml 2 times a day for 10 consecutive days, 20 inhalations. The control group (39 people) received individual chemotherapy according to the resistance profile with standard mucolytic treatment. The examination was carried out before the course with the mucoactive drug (visit I), then at the end of the course – after 10 days (visit II) and after 30 days (visit III) from the moment of inclusion in the study. The significance of differences (p) was determined at p <0.05 using χ² Pearson, Fisher's exact test, Mann-Whitney test, and paired Wilcoxon test. Results. There was an increase in the effectiveness of treatment of patients in this category according to the following criteria: disappearance or decrease of respiratory symptoms (on the 10th day from the start of treatment), early regression of inflammatory changes in the tracheobronchial tree (on the 30th day from the start of treatment in 24 (73.4%) patients in the main group, in 10 (25.1%) patients in the comparison group (RR = 3.34; 95% CI 2.78-3.90)].
Parameters of hepatotoxic reactions caused by the combination of first line anti-tuberculosis drugs in rats with different acetylation phenotypes
Authors: Mozhokina G. N. , Kazakov А. V. , Zyuzya Yu. R. , Petrova L. Yu.
Published: August 2020

The objective:in the experiment, to study specific parameters of manifestations of hepatotoxic reactions to the combination of anti-tuberculosis drugs containing isoniazid and rifampicin in rats with different acetylation phenotypes.Subjects and methods.Liver damage was modeled in rats, old females, belonging to the phenotype of rapid acetylation, and in mature males, belonging to the phenotype of slow acetylation, with a combination of basic anti-tuberculosis drugs, which were administered for 14 days. Hepatotoxic reactions were assessed by clinical observations of rats, biochemical parameters and morphological changes in the liver, which were compared with intact animals.Results of the study:in female rats (fast acetylators of isoniazid), signs of the cytolytic mechanism of liver damage prevailed (more significant elevation of ALT activity, pronounced duration of thiopental sleep, pronounced hydropic degeneration of hepatocytes with the presence of hepatocyte necrosis, venous congestion and edema of the portal tracts). In males (with the phenotype of slow acetylation of isoniazid), a significant elevation of total and direct bilirubin levels, AST activity and, to a lesser extent, ALT were observed, i.e., signs of a mixed mechanism of liver damage (cholestatic and cytolytic).
Reliability and Validity of Instruments Measuring English Teachers’ TPACK
Authors: ARSLAN Abdullah
Published: August 2020

In this study, issues of validity and reliability of a wide range of instruments used to measure technological pedagogical content knowledge level of English teachers were discussed. To this end, the search in the databases of ERIC, ScienceDirect, Scopus, EBSCOhost, and Web of Science was conducted. As a result of applying a set of criteria to publications retrieved from the databases, 60 studies (including 40 articles, 14 dissertations and 6 conference papers) were found suitable for analysis in the current study. A two-level analysis was conducted. First one was study-level analysis focusing on general characteristics of each study and the second one was an instrument-level analysis that focuses on target audience and research instruments. As a consequence of the analysis at the study-level, 128 instruments were classified into five types of instruments including, open-ended questionnaire, observation, performance assessment, interview, and self-report instruments. At the instrument-level analysis, issues of validity and reliability of those instruments and target audience were investigated. The findings revealed that 60% of the reviewed studies did not provide any index of reliability, and similarly over 80% of the studies presented no evidence of validity.
Factors Affecting Level of Children Resilience and Teachers’ Opinions about Resilience
Authors: YOLERI Sibel
Published: August 2020

This research mainly focuses on two purposes, the first of which is to examine the relationship between the resilience levels of 5-6-year-old preschool children, their temperament, and their ages. The second purpose of the research is to determine the opinions of their teachers on resilience and resilient children, the risk factors that affect the resilience and the protective factors. Accordingly, the mixed- method design was used in the study. The sample in the quantitative part of the study consisted of the parents and teachers of the 151 children enrolled in preschool education under the Usak Provincial Directorate for National Education. Qualitative data were collected from the interviews with 15 preschool teachers. The quantitative data were collected using the "Early Childhood Resilience Scale" and "The Short Temperament Scale for Children". The qualitative data were collected using the "Semi-structured Interview Form” which consists of 4 questions regarding the 15 preschool teachers’ opinions on resilience. According to the results, the age and temperament (i.e., persistence and reactivity) were found to be significant predictors of resilience. It was also found that the resilience scores of the children increased with age. The qualitative data were analyzed using descriptive and content analysis methods. The teachers expressed the highest rate of resilience as “being able to struggle”, while the characteristics of the children, who have resilience behaviour, were described as “being determined”. They expressed the concept of “domestic violence” as a risk factor that may influence resilience, and “personality traits” as the protective factor.
Computer simulation and investigation vibration parameters of a centrifugal submersible pump
Authors: Isametova Madina , Omarbekov Beknur , Nussipali Rollan , Angarbekov Ulan , Isametov Aysen
Published: August 2020

The dynamic characteristics of one of the centrifugal pump critical parts such as the rotor shaft are studied in the article whilst the highest level NASTRAN CAD PATRAN module was used to carry out the dynamic analysis. During the analysis a computational mechanical scheme has been compiled as well as force factors generating rotor vibrations have been determined. The axial, radial and hydrodynamic forces affecting the impeller and pump shaft have been calculated according to the analytical formula. Under the given boundary conditions in the FE model and the chosen method for determining the natural vibrations, a numerical solution of the equations of free and forced vibrations has been found using the algorithms of the NASTRAN program. The natural vibrations of the rotor have been determined using the Lanczos method. The dynamic stability of the shaft, the stress-strain state of the shaft and its displacement under static loads, the frequency and shape of the natural vibrations of the rotor necessary for the calculations have been determined. The amplitude-frequency characteristics of the system have been determined and analyzed for affection by external forces at the reverse and blade frequencies. Using the amplitude parameters of the forced oscillations, the dynamic gain of the rotor has been determined. Based on the amplitude-frequency parameters, the option of the number of blades for the working centrifugal impeller of the pump has been justified. The technique of computer simulation and determination of the vibroactivity parameters of a submersible centrifugal pump rotor shaft is given in the article.
Experimental study on vibration characteristics of fluid-solid coupling cantilever thin aluminum plate
Authors: Yinhanga Ma , Hanyanga Jiang , Meilingb Dai , Fujuna Yang
Published: August 2020

Compared with the general environment, the modal characteristics of structures under fluid-solid coupling will show great differences. Reasonable experimental methods can provide reliable conclusion support for fluid-solid coupling research. In order to explore the modal characteristics of structures under the action of fluids, the interference and finite element numerical calculation methods are used to study the dry and wet modal characteristics of the cantilever aluminum plate under fluid-solid coupling. According to the amplitude fluctuation resonance discrimination method, the resonant frequency and mode of the cantilever aluminum plate under different working conditions are obtained accurately. Experiments show that the effect of the fluid will greatly reduce the natural frequency of the structure and have little effect on the vibration mode. With the gradual increase of the fluid-solid coupling interface, the natural frequency drop rate and the amplitude at the gas-liquid interface remain consistent, and slightly ahead of the amplitude characteristics. At the same time, for each mode with the same characteristics, the frequency decreasing trend is linear, such as the first few pure bending vibration modes, and the first few bending and twisting combined vibration modes contain first-order twisting vibration. The experimental results and the finite element numerical results are in good agreement, which shows that the electronic speckle method is a good test method for studying fluid-solid coupling modes. Most importantly, the experimental conclusion has reliable reference value for practical engineering applications.
Fuzzy neural network control for mechanical arm based on adaptive friction compensation
Authors: Yang Hui , Wu Saiyan , Huang Gang
Published: August 2020

When tracking the trajectory of the mechanical arm in a joint space, the system is affected by friction non-linearity, unknown dynamic parameters and external disturbances that makes it difficult to improve the control accuracy of the mechanical arm. To solve the above problems, this paper introduces LuGre friction model and designs a new joint space trajectory tracking controller based on the adaptive fuzzy neural network. The controller is capable to make the adaptive adjustment of the center and width of the basis function, can approach the nonlinear link having the LuGre friction on line, and uses the sliding mode control term to reduce the approximation error. The introduction of LuGre model into the mechanical arm system can more truly simulate the friction link of the system, which is of great significance to the high precision control of the mechanical arm. The Lyapunov method is used to prove the stability of the closed-loop system. The simulation results show that the designed adaptive fuzzy neural network can effectively compensate the non-linear links including friction without precise system parameters, and the controller has strong robustness to load changes, thus realizing high-precision trajectory tracking of the mechanical arm in joint space.
Numerical analysis of the flow mechanism and axial force characteristics of the cavity in a centrifugal pump with a front inducer
Authors: Zhang Haichen , Dong Wei , Chen Diyi
Published: August 2020

At three flow conditions (0.8Qd, 1.0Qd, and 1.2Qd), the centrifugal pump cavity with front inducer was expanded at 0°, 90°, 180°, and 270°, and a flow path analysis of the axial cross section at the four angles was performed. This revealed that the circumferential and radial velocities of the liquid in the pump cavity along the same angle at different radii follow an axial and radial variation law to different degrees. The pump cavity center axial liquid velocity component along the radial distribution at different angles was analyzed, and liquid pressure in the pump cavity along the radial distribution was numerically analyzed from different points of view. The mean pump cavity pressure was plotted along the radial distribution curve, and a detailed numerical calculation of the axial force of the centrifugal pump and pump cavity was developed. The influence of flow conditions on the liquid flow mechanism and axial force characteristics in the pump cavity was thoroughly discussed. The results showed that liquid flow in the centrifugal pump cavity with the front inducer is mainly restricted by the main flow of the volute. The liquid eddy current in the pump cavity is mainly concentrated near the volute and the hub at 90° and 180° angles, and the higher the flow rate, the larger is the area of the side vortex of the impeller-cover plate, and the smaller is the area of the side vortex of the pump-cover plate. When the flow rate increases, the flow direction of the eddy current at the same angle in the pump cavity remains unchanged, but when the flow rate becomes too high, the flow direction of the eddy current at the same angle in the pump cavity changes. When the range of circumferential and radial partial velocities decreases, the rotational angular velocity increases, and the pressure decreases. At low flow rate, the larger the area of the volute corresponding to the pump cavity, the higher the speed becomes. The axial force in the pump cavity is the most important factor determining the axial force of the centrifugal pump.
Ride comfort performance of hydro pneumatic isolation for soil compactors cab in low frequency region
Authors: Jiao Renqiang , Nguyen Vanliem , Le Vanquynh
Published: August 2020

The hydro pneumatic isolation (HPI) of the cab combined by the high static stiffness and nonlinear viscous damping of the pneumatic isolation; and nonlinear adjustable damping of the hydraulic isolation are proposed. Based on the simulation and experimental studies, a nonlinear dynamic model of the soil compactor interacting with the deformable terrains is built to analyze the low frequency ride comfort of the HPI. The HPI’s performance for improving the ride comfort and health of the driver is evaluated via both the power-spectral-density and root-mean-square of acceleration responses of the driver’s seat heave, pitching and rolling cab angles. The research results show that the HPI’s characteristics with high static stiffness and nonlinear damping have an obvious impact on reducing low frequency vibration and controlling the cab shake of the vehicle in comparison with the traditional rubber mounts.
Removal Modeling of Encapsulated L.minor by Alginate Microspheres
Authors: UCUNCU TUNCA Esra , TÜRE Hasan
Published: August 2020

The aim of the study was to model the efficiency of different sorbents (Lemna minor (L), alginate microspheres (A) and encapsulated L.minor (capsA+L)) on the removal of malachite green dye(MG) by using regression analysis. One other purpose was to specify the effects of encapsulation on the removal process. Linear and cubic estimation models were constructed and it was seen that R2 values of cubic models were higher (0.988-1.0). It was observed that group (A) was less successful on MG removal compared to other groups (L>capsA+L>A). Encapsulation increased the removal capacity of microspheres but still did not attain the efficiency of (L) group that was (70.22-85.69%).
Farklı Bakteri Uygulamalarının Domates (Solanum lycopersicum L.) Bitki Gelişimi Üzerine Etkileri
Authors: UYSAL ŞAHİN Badel , DÖNMEZ Mesude Figen
Published: August 2020

Bu çalışma, 2015 yılında Iğdır ili volkanik, kumlu ve tuzlu topraklarından elde edilen 25 PGPR straininin domates (Solanum lycopersicum L.) bitkisinin gelişimine etkisini değerlendirmek amacıyla yürütülmüştür. İzole edilen bakterilerin tanısı Mikrobiyal Tanılama Sistemi (MIS) kullanılarak gerçekleştirilmiştir. Azot fikse etme ve fosfat çözme özellikleri belirlenen strainlerin domates gelişimine etkisi gübre ve kontrol uygulamaları ile kıyaslanmış, ortalama ana kök uzunluğu, ortalama yan kök uzunluğu, bitki yüksekliği, gövde çapı ve dal sayısı parametreleri incelenmiştir. Çalışmanın sonucunda; Bacillus atrophaeus, Bacillus gordonae, Bacillus licheniformis, Bacillus megaterium, Bacillus sphaericus, Bacillus subtilis, Bacillus thuringiensis kurstakii, Bacillus viscosus, Brevibacillus centrosporus, Brevibacillus choshinensis, Chryseomonas luteola, Microbacterium lacticum, Micrococcus luteus, Micrococcus lylaei, Pseudomonas balearica, Pseudomonas pseudoalcaligenes, Pseudomonas putida, Sphingobacterium faecium, Sphingomonas paucimobilis, Staphylococcus cohnii cohnii, Staphylococcus gallinarum ve Virgibacillus pantothenticus olmak üzere 14 tür tanılanmıştır. Bakteri uygulamalarının ele alınan parametreleri gübre ve hiç uygulama yapılmayan kontrol bitkilere kıyasla önemli düzeyde arttırdığı ve en yüksek etkinin Bacillus spp. türlerinde olduğu tespit edilmiştir.
Analysis of The Dynamics of The Classical Epidemic Model with Beta Distributed Random Components
Authors: KESEMEN Tülay , MERDAN Mehmet , BEKİRYAZICI Zafer
Published: August 2020

In this study, the classical epidemic model of Kermack and McKendrick is analyzed with beta distributed random components. A random analysis is done for the deterministic epidemic model by transforming the parameters and initial values of the system to random variables with beta distribution. The approximations for the expectations of the model variables are compared with the deterministic results to comment on the randomness of the cases with random parameters and random initial values. Results for some numerical characteristics of these two cases are also given to investigate the accuracy of the approximations for the expected values.
Bazı Tahıl ve Tahıl Benzeri Unların Yenilebilir Film ve Kaplama Potansiyellerinin Belirlenmesi
Authors: KARAHAN Ali Mücahit , MERAL Raciye , KILINÇÇEKER Osman
Published: August 2020

Yenilebilir filmler ve kaplamalar, gıdaların yüzeyine ince tabaka halinde uygulanan ve gıdaları dış ortamdan koruyan ve polisakkarit ve/veya protein kullanılarak ya da bitkisel kaynaklı unlar kullanılarak hazırlanan materyallerdir. Bu çalışmada, yerel satıcılardan temin edilen buğday, mısır, chia, tef, karabuğday ve kinoa unlarının protein, nişasta, nem değerleriyle su absorbsiyon oranları incelenmiş ve bu unların yenilebilir film ve kaplama olarak kullanılma potansiyelleri belirlenmiştir. Unların protein oranlarının %6.40-19.64; nişasta oranlarının %2.87-71.63 arasında değiştiği belirlenmiştir. Unların partikül büyüklükleri varyasyon göstermiş ve en ince partiküle sahip unun buğday unu, en yüksek partikül büyüklüğüne sahip unun chia unu olduğu saptanmıştır. Su absorbsiyon değerleri chia unu için en yüksek (%404.03), buğday unu için en düşük (%5.15) olarak belirlenmiştir. Çalışma sonucunda bu unların kimyasal ve fiziksel özellikler açısından yenilebilir kaplama formülünde kullanılabileceği sonucuna varılmıştır.
Kapalı Otopark Aydınlatmasında Floresan ve LED Lambanın Enerji Verimliliği Açısından Karşılaştırılması
Authors: KOCAMAN Behçet
Published: August 2020

Elektrik enerjisi tüketimi, hızlı nüfus artışı ve teknolojideki gelişmelere bağlı olarak her geçen gün artmaktadır. Aydınlatma, elektrik enerjisinin tüketiminde önemli bir yere sahiptir. Bu nedenle aydınlatmada enerji verimliliği konusunda çalışmalar ön plana çıkmaktadır. Enerji verimliliği için aydınlatmada kullanılan lambaların özellikleri etkin rol oynamaktadır. Aydınlatmada enerji verimliğini sağlamak için çeşitli LED (Işık Yayan Diyot) uygulamaları geliştirilmiş ve LED’in karakteristik özelliği nedeniyle farklı noktalarda uygulanmaktadır. Otopark gibi bazı belirli yerlerdeki aydınlatmada enerji verimliliğini artırmak için incelenmesi gerekir. Bu çalışmada, Bitlis Eren Üniversitesine ait kapalı otopark aydınlatmasında kullanılan floresan lamba yerine LED lamba kullanılmasının enerji verimliliği açısından karşılaştırılması yapılmıştır. Çalışmanın sonucunda, kapalı otopark aydınlatmasında 2 x 36 W floresan lamba yerine 48 W LED lamba kullanımıyla yılda 23 757.12 kWh enerji tasarrufu sağlanacağı ve yatırım maliyetinin de 1.83 yıl içerisinde amorti edileceği hesaplanmıştır.
T Kaotik Sisteminin Geri Besleme ile Kontrolü
Authors: EMİROGLU Selcuk , UYAROĞLU Yılmaz
Published: August 2020

Bu çalışmada, T sisteminin kaotik davranışı Lyapunov üstelleri, Kaplan-Yorke boyutu ve denge noktaları analiz edilerek gösterilmiştir. Daha sonra belirli parametreler altında kaotik davranış gösteren T sisteminin doğrusal geri beslemeli kontrol yardımıyla kontrolü araştırılmıştır. Denge noktaları etrafında kontrol edilen sistemin kararlılığını sağlamak için Routh-Hurwitz kriteri kullanılmıştır. T kaotik sistemini tek durum değişkeni geri besleme ile kontrol etmek için geri besleme katsayısı hesaplanmış daha sonra iki ve üç durum geri besleme ile sistemin kontrolü için aynı işlemler tekrarlanmıştır. Routh-Hurwitz kriteri kullanılarak geri besleme katsayıları hesaplanarak tasarlanan kontrolör T kaotik sistemine eklenmiştir. Kontrollü sistemde geri besleme katsayısı değişiminin sistemin kontrolünü nasıl etkilediği faz portreleri ile gösterilmiştir. Doğrusal geri beslemeli kontrolörün tasarlanması ve uygulanması oldukça basittir. Kontrolör basit yapıya sahip olduğundan donanımsal olarak maliyeti düşüktür ve pratik olarak gerçeklenmesi kolaydır. Geri beslemeli kontrolün uygulanmasıyla kontrollü sistemin sıfır ve diğer denge noktalarına yakınsadığı bilgisayar benzetim çalışmalarıyla gösterilmiştir.
Kanserli ve Sağlıklı Larenks Dokularında ICP-MS Yöntemi ile Eser Elementler Analizi
Authors: KOÇAK Ömer Faruk , ALBAYRAK Mevlüt , ÖZGERİŞ Fatma Betül
Published: August 2020

Eser elementler vücudun düzgün çalışması için gereklidir. Biyolojik element konsantrasyonundaki değişiklikler çok sayıda patolojik durumda gözlenmiştir. Bu çalışmanın amacı, larenks dokularındaki eser element konsantrasyonunun değerlendirilmesidir. Çalışmada larenks kanseri teşhisi konmuş 9 hastanın kanserli larenks dokuları ve aynı hastaların sağlıklı larekns dokuları kullanılmıştır. Larenks dokularındaki Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sb ve Pb seviyeleri, Endüktif Eşleşmiş Plazma Kütle Spektrometresi (ICP-MS) kullanılarak belirlenmiştir. Sonuçlar kontrol grubu ile karşılaştırıldı ve larenks kanserli dokularda Cu seviyesinin sağlıklı dokulara göre anlamlı derecede (p <0.05) yüksek olduğu ve Al, Cr, Mn, As, Se, Ag ve Sb elementlerinin derişiminin ise sağlıklı dokulara göre anlamlı derecede düşük olduğu bulundu. Bu sonuçlar, larenks kanseri etyolojisinde eser elementlerin önemli rolleri olduğunu düşündürmektedir.
Kuru Kumlarda Dane Çapı Dağılımının İçsel Sürtünme Açısına Etkisinin Kesme Kutusu Deneyleri ile Belirlenmesi
Authors: KARAKAN Eyyüb , EBREN Zelal
Published: August 2020

Laboratuvardaki içsel sürtünme açısını ve kohezyon değerlerini belirlemek için yapılan en yaygın deneylerden biri direk kesme testidir. Bu çalışma için, tamamen kuru zeminlerin dayanım parametrelerinin, farklı rölatif sıkılıklar ve normal gerilmelerdeki değişimleri incelenmiştir. Deneysel çalışma direk kesme testi, beş farklı normal gerilme ve sabit numune hacmi altında yapılmıştır. Kumun kohezyonunun sıfır olduğu varsayımı ile karşılaştırma yalnızca içsel sürtünme açısına bağlı olarak gerçekleştirilmiştir. Elde edilen kayma mukavemeti açısı değerleri ile rölatif sıkılık ve normal gerilme ilişkisi, zemin tane çapı değişimi parametresi de göz önünde bulundurularak incelenmiştir. Numunelerin test edildiği rölatif sıkılıklarda, içsel sürtünme açısı gibi fiziksel özelliklerin artışını içeren normal gerilmedeki artışla birlikte maksimum ve artık kayma gerilmesinde de bir artış olduğu görülmüştür. Ayrıca elde edilen sonuçlar, zeminin dane çapı dağılımının içsel sürtünme açısını nasıl etkilediğini göstermiştir.
Geri Dönüştürülmüş Beton Agregasının Düşük Plastisiteli Bir Kilin Mekanik Özelliklerine Etkisi
Authors: BİLGEN Gamze
Published: August 2020

Bu çalışmada, beton dayanımını belirlemek amacı ile test edilmiş olan beton numunesi atıklarının ufalanması ile elde edilmiş olan geri dönüştürülmüş beton agregalarının (GDA) yol ve dolgu yapımında alt temel malzemesi olarak kullanımı üzerine deneysel bir araştırma yapılmıştır. Beton numunesi atıkları laboratuvar ortamında el yordamı ile kırılıp elenmek sureti ile deneyler için gerekli boyutlara indirilmiştir. Bölge civarında temin edilen killi zemin, dolgu yapımında kullanılacak alt temel malzemesi olarak seçilmiştir. 425 mikron boyutundan elenerek (40 nolu elek) hazırlanmış olan GDA, alt temel zemini ile %5, %10 ve %15 oranlarında karıştırılmak sureti ile farklı karışım oranlarında örnekler hazırlanmıştır. GDA nın killi zeminin mekanik özelliklerine etkisinin belirlenmesi için hazırlanan karışımlar üzerinde; standart Proctor, serbest basınç dayanımı (UCS) ve Kaliforniya taşıma oranı (CBR) şeklinde bir seri deney gerçekleştirilmiştir. Deneysel çalışmanın sonuçlarına göre GDA düşük plastisiteli killi zeminin mekanik özelliklerini iyileştirmektedir.
Preparation of Metal Complexes of 4,5-Dichlorphthalic Acid as Nanoscale and Electronic Properties
Authors: KESKİN Mehmet Salih , YILDIKO Ümit , GÜNGÖRDÜ SOLĞUN Derya , AĞIRTAŞ Mehmet Salih
Published: August 2020

Here phthalic acid metal complexes with acid function were synthesized. Fourie transform infrared spectroscopy (FT- IR), X-ray diffraction analysis (XRD), Scanning electron microscopy-Energy Dispersive Spectrometry (SEM+EDS) devices were used for structure analysis. The structural parameters of the copper and zinc complexes of 4,5-dichlorphthalic acid were determined by the LanL2DZ basis base set of B3LYP method. Electronic properties such as HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies and molecular electrostatic potential (MEP) were obtained. Stability, charge delocalization of molecules resulting from hyperconjugative interactions were analyzed using natural bond orbital (NBO) analysis. The comparison of the theoretical and experimental FT-IR spectra of Zn and Cu-4,5-dichlorphthalic acid (DCPA) were made and R = 0.97204 for Cu and R = 0.97929 for Zn complex were found in linear fit studies. Two characterization results were found to be consistent.
İlkokul Çevresinde Gürültü Kirliliğinin Belirlenmesi: Bursa İli Örneği
Authors: YALILI  KILIÇ Melike , ADALI Sümeyye
Published: August 2020

Gürültü, insanlara rahatsızlık veren ve kent yaşamında istenmeyen bir çevre kirliliğidir. Su, hava, toprak ve katı atık gibi çevre kirliliklerinin dışında gürültü kirliliği çok fazla önemsenmemektedir. Aslında gürültü insanlarda işitme kaybı, performans düşüklüğü, dikkatini verememe, odaklanamama, zihinsel çalışamama, uyku ve denge bozukluğu gibi pek çok rahatsızlıklara neden olmaktadır. Gürültünün oluştuğu yerlerden birisi de okulların çevresidir. Özellikle zilin çalması ile öğrencilerin okul bahçesine çıkmaları veya derse başlamak için binaya girmeleri, bahçede oyun esnasında yoğun olarak gürültü oluşmasına neden olmaktadır. Bu gürültü ise, okul çevresindeki evlerde ve dükkanlarda bulunan kişilerde zaman içerisinde psikolojik, fizyolojik ve fiziksel pek çok hastalıkları ortaya çıkarır. Bu çalışmada, Bursa’nın Mudanya ilçesinde bulunan bir ilkokulun çevresinde gürültü düzeyinin belirlenmesi amacıyla ölçümler yapılmış ve sonuçlar istatistiksel olarak yorumlanmıştır. Ölçümler okul bahçesine giriş kapısı ile okul binasına giriş kapısına yakın olan iki noktada, hafta içi pazartesi, çarşamba ve cuma günleri teneffüslerde 5’er dakika boyunca gerçekleştirilmiştir. İlave olarak pazartesi ve cuma günleri bayrak törenleri esnasında 10 dakikalık periyot boyunca da ölçümler alınmıştır. Elde edilen sonuçlar, Çevresel Gürültünün Değerlendirilmesi ve Yönetimi Yönetmeliği’nde (ÇGDYY) verilen sınır değerlerle karşılaştırılmıştır. ÇGDYY’ye göre eğitim alanlarının bulunduğu mevcut yollarda gündüz saatlerinde gürültü değerlerinin 65 dBA’yı aşmaması gerektiği ifade edilmektedir. Bu çalışma kapsamında elde edilen sonuçların ÇGDYY’de verilen sınır değeri aştığı görülmüş olup, bu bölgede gürültünün azaltılması için çeşitli önerilerde bulunulmuştur.
İHA Kanatlarında Kullanılan Cam ve Karbon Elyaf Takviyeli Kompozitlerin Yapısal Performanslarının Sayısal Simülasyonlar ile İncelenmesi
Authors: ÖZTÜRK Ahmet Mesut , GÜNDOĞDU Ömer
Published: August 2020

Kompozit malzemeler yüksek özgül mukavemet, korozyon direnci, titreşim sönümleme kabiliyeti gibi birçok avantajlı özelliğe sahip oldukları için başta havacılık ve otomotiv olmak üzere birçok sektörde sıklıkla tercih edilmektedirler. Bu çalışma kapsamında kompozit malzeme ve metalik malzemelerin birlikte oluşturduğu bir insansız hava aracı kanadının yapısal davranışı teorik olarak incelenmiştir. Çalışmada iki farklı kanat geometrisi üzerinde durulmuştur. Birincisi, flap ve aileron bulundurmayan yekpare bir kabuğa sahip kanat geometrisidir. Bu kanat geometrisi Model 1 olarak isimlendirilmiştir. İkincisi ise üzerinde flap ve aileron kontrol yüzeylerini ve ilgili tüm yapısal elemanlarını barındıran kanat geometrisidir ve bu kanat geometrisi ise Model 2 olarak adlandırılmıştır. Referans alınan teorik kanat modelini yapısal olarak geliştirmek amacıyla farklı malzeme sistemlerinin kullanıldığı yeni teorik kanat modelleri oluşturulmuştur. Bu modeller yatay uçuş seyir şartları ve maksimum statik basınç yükü altında yapısal analizlere tabi tutulmuş en uygun konfigürasyonlar ortaya konulmuştur.
İnsan Serum Paraoksonaz-1 (hPON1) Üzerine Bendamustin İnhibisyon Etkisi
Authors: SÖYÜT Hakan , ULUTAŞ Yakup , KÖKSAL Ekrem
Published: August 2020

hPON1, HDL ile ilişkili ve 43-45 kDa'lık bir moleküler kütleye sahip olan bir ester hidrolazdır. Karaciğerde sentezlenir. Organofosfat ajanlarını ve sinir gazlarını hidrolize eder. LDL'nin oksidasyonuna ve lipit peroksitlerin ve bakteriyel endotoksinlerin oluşumuna karşı koruyucu bir rol oynar. LDL'nin oksidasyonunun ateroskleroz sürecinin başlangıç aşamasını oluşturması, hPON1 antioksidan özelliklerinin önemini göstermektedir. Birçok epidemiyolojik çalışma HDL kolesterol düzeyleri ile kardiyovasküler olaylar arasında ters bir ilişki olduğunu göstermiştir. Yüksek serum HDL-kolesterol ve düşük LDL-kolesterol seviyelerinin koroner kalp hastalığı ve ateroskleroz gelişimine karşı koruyucu olduğu bilinmektedir. Bu nedenle, hPON1 bir HDL bileşenidir, bu nedenle koroner arter hastalığında HDL'nin koruyucu rolüne katkıda bulunur. Bu araştırmada, in vitro koşullarda insan serumunda hPON1 enzim aktivitesi üzerine bendamustin kemoterapik ilacının inhibisyon etkisini araştırdık.
Antioxidant Potential and Tyrosinase Inhibitory Properties of Quebecol as Natural Phenolic Compound
Authors: TASLIMI Parham
Published: August 2020

In this paper, we investigated the antioxidant potential of Quebecol in vitro using several assays. These; Cu2+-Cu+ reducing, DPPH• scavenging, Fe3+-Fe2+reducing, ABTS•+ scavenging. The IC50 amounts of the Quebecol in the DPPH• and ABTS•+ methods were 14.78 and 5.38 μg m1, respectively. Tyrosinase enzyme is a functional oxidase that is extensively divided in nature. It is the main enzyme in melanin synthesis and also is involved in designating the color of mammalian hair and skin. Recently, there has been a remarkable concern to study the inhibitory activity of the tyrosinase enzyme and some inhibitory molecules isolated from natural sources. For tyrosinase enzyme, Quebecol and kojic Acid (Standard) as natural phenols have IC50 values of 4.64 and 9.28 μM.
Isolation and Characterization of CD39-like Phosphodiesterase (Cc-PDE) from Cerastes cerastes Venom: Molecular Inhibitory Mechanism of Antiaggregation and Anticoagulation
Authors: Kiheli Hamida , Chérifi Fatah , Ameziani Meriem , Saoud Samah , Hariti Ghania , Laraba-Djebari Fatima
Published: August 2020

Background:

Cerastes cerastes venom contains several bioactive proteins with inhibitory
potential of platelet aggregation and blood coagulation.

Objective:

The current study deals with purification, characterization and determination of structural
properties of Cc-PDE, the first phosphodiesterase from Cerastes cerastes venom.

Material and Methods:

The purification process consists of three successive chromatographies including
G75-Sephadex size exclusion, DEAE exchange chromatography and affinity using Sildenafil
as a main PDEs’ specific inhibitor. The amino acid sequence of purified Cc-PDE was determined
by liquid chromatography coupled off line to MALDI-TOF/TOF. Modeling and structural
features were obtained using several bioinformatics tools. In vivo and in vitro antiplatelet aggregation
and anticoagulant assays were performed.

Results:

Cc-PDE (73 506.42 Da) is a 654-residue single polypeptide with 1-22 signal peptide and
it is characterized by the presence of predominant basic amino acids suitable to alkaline pI (8.17).
Cc-PDE structure is composed of β-strands (17%) and α-helices (24%) and it shares a high identity
with homologous snake venom PDEs. Cc-PDE hydrolyzes both Bis-p-nitrophenyl phosphate (Km
= 2.60 ± 0.95 mM, Vmax = 0.017 ± 0.002569 μmol.min-1) and p-nitrophenyl phosphate (Km =
7.13 mM ± 0.04490 mM, Vmax = 0.053 ±0.012 μmol.min-1). Cc-PDE prevents ADP- and ATP-induced
platelet aggregation by hydrolyzing ADP and ATP, reducing surface P-selectin expression
and attenuating platelet function. In addition, Cc-PDE inhibits coagulation factors involved in the
intrinsic pathway demonstrated by a significant prolongation of activated partial thromboplastin
time and in vivo long-lasting anticoagulation.

Conclusion:

The obtained results revealed that Cc-PDE may have a therapeutic potential and could
be a remedy for thromboembolic diseases as an alternative of anticoagulant and antiplatelet aggregation
chemical origins.
Antinociceptive Effects of VV-Hemorphin-5 Peptide Analogues Containing Amino phosphonate Moiety in Mouse Formalin Model of Pain
Authors: Assenov Borislav , Pechlivanova Daniela , Dzhambazova Elena , Peneva Petia , Todorov Petar
Published: August 2020

Background:

Hemorphins are endogenous hemoglobin-derived peptides that belong to
the family of “atypical” opioid peptides with both affinities to opioid receptors and ability to release
other endogenous opioid peptides.

Objective:

In the present study, peptide analogues of Valorphin (VV-hemorphin-5) containing amino
phosphonate moiety synthesized by solid-phase peptide synthesis (Fmoc-strategy) were investigated
for their potential antinociceptive activities and compared to the reference VV-H in formalin-
induced model of acute and inflammatory pain in mice.

Methods:

The hemorphin analogues were prepared by replacement of the one and/or two N-terminal
Val in VV-hemorphin5 (VV-H) with ((dimethoxy phosphoryl) methyl)-L-valine and
((dimethoxy phosphoryl) methyl)-L-leucine to obtain the compounds pVV-H, pL-H, and pLV-H.
Aiming to additionally prove the importance of amino acid valine, we introduced the ((dimethoxy
phosphoryl) methyl)-L-leucine to the N-side of VV-hemorphin-5 (pLVV-H). The experiments
were carried out on adult male ICR mice. All peptides were administered intracerebroventricularly
at three doses (50, 25 and 12,5 μg/mouse). We have studied the effects of the peptides on acute (1st
phase) and inflammatory (2nd phase) pain reaction using un experimental model with intraplantar
formalin injection.

Results:

VV-H showed a significant antinociceptive effect both in the acute and inflammatory phases
of the test. Although Valorphin hexa-, hepta-, and octapeptide analogs demonstrated a significant
antinociceptive effect, they showed substantial differences considering their effective dose and
the phase of the test as compared to the Valorphin.

Discussion:

Data showed that modified heptapeptides pVV-H and pLV-H exerted the same or better
antinociception in acute and inflammatory pain, in comparison to the reference peptide, while
pL-H and pLVV-H analogues were less effective.

Conclusion:

Our study contributes to the elucidation of the role of Valine and the number of amino
acid residues in the structure of hemorphin peptide analogs in their effectiveness in suppressing
both acute and inflammatory experimental pain.
Construction and Evaluation of Peptide-Linked Lactobacillus brevis β-Galactosidase Heterodimers
Authors: Han Yuan-Yuan , Yue Hai-Yun , Zhang Xiao-Yang , Lyu Yong-Mei , Liu Li , Voglmeir Josef
Published: August 2020

Background:

β-galactosidases are enzymes that are utilized to hydrolyze lactose into galactose and glucose, and are is widely used in the food industry.

Objective:

We describe the recombinant expression of an unstudied, heterodimeric β-galactosidase originating from Lactobacillus brevis ATCC 367 in Escherichia coli. Furthermore, six different constructs, in which the two protein subunits were fused with different peptide linkers, were also investigated.

Methods:

The heterodimeric subunits of the β-galactosidase were cloned in expressed in various expression constructs, by using either two vectors for the independent expression of each subunit, or using a single Duet vector for the co-expression of the two subunits.

Results:

The co-expression in two independent expression vectors only resulted in low β-galactosidase activities, whereas the co-expression in a single Duet vector of the independent and fused subunits increased the β-galactosidase activity significantly. The recombinant β-galactosidase showed comparable hydrolyzing properties towards lactose, N-acetyllactosamine, and pNP-β-D-galactoside.

Conclusion:

The usability of the recombinant L. brevis β-galactosidase was further demonstrated by the hydrolysis of human, bovine, and goat milk samples. The herein presented fused β-galactosidase constructs may be of interest for analytical research as well as in food- and biotechnological applications.
Biophysical Characterization of Type III Pantothenate Kinase (PanK) from Acinetobacter baumannii
Authors: Singla Ankita , Sharma Pradeep , Gupta Akshita , Iqbal Naseer , Rani Chitra , Singh T.P. , Sharma Sujata
Published: August 2020

Background:

Type-III Pantothenate kinase from the multi drug resistant bacteria, Acinetobacter
baumannii (AbPanK) catalyzes the first step of the essential Coenzyme A biosynthesis
pathway. AbPanK is an attractive drug target against the bacteria since it is an essential enzyme
and its structure is significantly different from the human PanK.

Methods:

AbPanK was cloned, expressed, purified and crystallized. A good quality single crystal
was used for X-ray intensity data collection. Dynamic light scattering was done for calculating the
hydrodynamic radii and its oligomeric nature in the solution. Binding studies of this protein with
its two substrates, Pantothenate and ATP were done using spectrofluorometer.

Results:

Our results indicated that AbPanK shows a strong affinity with pantothenate with dissociation
constant of 1.2 x 10-8 M and moderate affinity towards ATP of 3.7x 10-3 M. This fact was further
substantiated by the calculations of Km of both substrates using kinase assay kit. Dynamic
light scattering studies have shown that it exists as homogenous solution with hydrodynamic radii
corresponding to the molecular weight of 29.55 kDa. A low-resolution X-ray intensity data set was
collected, which shows that AbPank crystallizes in P2 space group with cell dimensions of a= 165
Å, b= 260 Å, and, c= 197 Å and α= 90.0, β= 113.60, γ= 90.0.

Discussion:

Recombinant Pantothenate kinase from Acinetobacter baumannii was purified to homogeneity
and crystallized. The enzyme exhibits very low sequence identity (28%) to other corresponding
enzymes.

Conclusion:

The recombinant enzyme was active and its binding affinities with its substrates pantothenate
and ATP have been studied. This information would be very useful while designing the
inhibitors of this enzyme in order to fight bacterial infections associated to this pathogen.
Investigation of the Role of Aromatic Residues in the Antimicrobial Peptide BuCATHL4B
Authors: Necelis Matthew R. , Santiago-Ortiz Luis E. , Caputo Gregory A.
Published: August 2020

Background:

Antimicrobial Peptides (AMPs) are an attractive alternative to traditional
small molecule antibiotics as AMPs typically target the bacterial cell membrane. A Trp-rich peptide
sequence derived from water buffalo (Bubalus bubalis), BuCATHL4B was previously identified
as a broad-spectrum antimicrobial peptide.

Objective:

In this work, native Trp residues were replaced with other naturally occurring aromatic
amino acids to begin to elucidate the importance of these residues on peptide activity.

Methods:

Minimal Inhibitory Concentration (MIC) results demonstrated activity against seven
strains of bacteria. Membrane and bilayer permeabilization assays were performed to address the
role of bilayer disruption in the activity of the peptides. Lipid vesicle binding and quenching experiments
were also performed to gain an understanding of how the peptides interacted with lipid bilayers.

Results:

MIC results indicate the original, tryptophan-rich sequence, and the phenylalanine substituted
sequences exhibit strong inhibition of bacterial growth. In permeabilization assays, peptides
with phenylalanine substitutions have higher levels of membrane permeabilization than those substituted
with tyrosine. In addition, one of the two-tyrosine substituted sequence, YWY, behaves
most differently in the lowest antimicrobial activity, showing no permeabilization of bacterial membranes.
Notably the antimicrobial activity is inherently species dependent, with varying levels of activity
against different bacteria.

Conclusion:

There appears to be little correlation between membrane permeabilization and activity,
indicating these peptides may have additional mechanisms of action beyond membrane disruption.
The results also identify two sequences, denoted FFF and YYW, which retain antibacterial activity
but have markedly reduced hemolytic activity.
Characterization of β-Sitosterol for Potential Selective GR Modulation
Authors: Leng Yue , Sun Yonghai , Lv Chengyu , Li Zhuolin , Yuan Cuiping , Zhang Jie , Li Tiezhu , Wang Yongjun
Published: August 2020

Background:

Although glucocorticoids (GCs) are characterized as powerful agents to treat inflammatory afflictions, they are accompanied by metabolic side effects which limit their usage. β-Sitosterol, as a minor component found in extraction of vegetable oil, was reported to have anti-inflammatory effects in RAW 264.7 cells.

Objective:

To test whether β-sitosterol has an effect to dissociate transrepression from transactivation as a selective novel GR binder, this work evaluated the dissociated characteristics of β-sitosterol.

Methods:

The probable binding interaction between β-sitosterol and GR was explored by molecular docking. The GR transcriptional activity of β-sitosterol was assessed in the reporter gene assay. The ability of β-sitosterol to modulate the transactivation and transrepression of GR was evaluated by real-time quantitative PCR analysis.

Results and Discussion:

In the present study, β-sitosterol treatment cannot induce GR-mediated transactivation. β-Sitosterol exerted a potential to inhibited the expression of GR target transrepressed gene without activating the expression of GR transactivation dependent gene. Molecular docking demonstrated that β-Sitosterol was able to bind the ligand binding domain of GR but unable to induce GR activation.

Conclusion:

This work offers evidence that β-sitosterol may serve as a selective GR modulator.