741 research outputs found
Eigenvalue Asymptotics for the Schr\"odinger Operator with a Matrix Potential in a Single Resonance Domain
We consider a Schr\"odinger Operator with a matrix potential defined in
by the differential expression\begin{equation*}
L(\phi(x))=(-\Delta+V(x))\phi(x)
\end{equation*}and the Neumann boundary condition, where is the
dimensional rectangle and is a martix potential, . We obtain the asymptotic formulas of arbitrary order for the single
resonance eigenvalues of the Schr\"odinger operator in .Comment: Presented by Setenay Akduman in the International Conference
"Analysis, Topoogy and Applications (ATA 2014)", Vrnja\v{c}ka Banja, Serbia,
May 26-29, 2014, Keywords: Schr\"odinger operator, Neumann condition,
perturbation, matrix potentia
The comparative study of nursing pads by electrospun cellulose acetate, polyethylene oxide and thermoplastic polyurethane nanofibers
This study summarizes the general information about nursing pads and novel electrospun nanofiber mats as potential component for nursing pads. It also compares electrospun thermoplastic polyurethane (TPU), cellulose acetate (CA) and polyethylene oxide (PEO) nanofibers with a polypropylene conventional disposable nursing pad (NP) in terms of hydrophilicity, breathability, air permeability and swelling properties. Nanofiber mats prepared by the electrospinning method have unique properties such as smooth surface, high specific surface area and high porosity with fine pores which will lead to improved wicking properties. These properties make nanofibers potential component for disposable nursing pads. Mean diameters of produced nanofibers were 284.39, 609.70 and 219.30 nm for CA, TPU and PEO, respectively. Water contact angle measurement revealed that these nanofibers show good wettability properties better than commercial nonwoven nursing mat and air permeability results revealed that these nanofibrous mats have considerably adequate permeability. Besides, water vapor permeability results showed these nanofibers still show good breathability despite their compact structure. © Published under licence by IOP Publishing Ltd
Nanofibers in face masks and respirators to provide better protection
A facemask is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. They are generally labelled as surgical, isolation, dental or medical procedure masks. On the other hand, respirators are personal air purifiers. They are designed to protect the wearer from inhaling dangerous substances such as toxic chemicals and infectious particles. Respirators are designed to help reduce the wearer's respiratory exposure to airborne contaminants such as particles that are small enough to be inhaled - particles less than 100 microns (μm) in size. A face masks or a respirator consist entirely or substantially of filter material or comprises a face piece in which the main filter(s) form an inseparable part of the device. Nanofibers could be the key elements for filter materials in face masks or respirators. They have a very high surface area per unit mass that enhances capture efficiency and other surface area-dependent phenomena that may be engineered into the fiber surfaces (such as catalysis or ion exchange). They could enhance filter performance for capture of naturally occurring nanoparticles such as viruses, as well as micron-sized particles such as bacteria or man-made particles such as soot from diesel exhaust. © Published under licence by IOP Publishing Ltd
Purification of yeast alcohol dehyrogenase by immobilized metal affinity chromatography
Bu tezde, poli(2-hidroksietil metakrilat-glisidilmetakrilat) [poli(HEMA-GMA)] kriyojelleri, HEMA ve fonksiyonel komonomer GMA'nın çapraz bağlayıcı olarak N,N'-metilen bisakrilamid (MBAAm) kullanılarak radikalik kriyokopolimerizasyon ile hazırlanmıştır. İminodiasedik asit (IDA) fonksiyonel grupları, poli(HEMA-GMA) kriyojellerindeki epoksi gruplarının halka yapılarının açılmasıyla kriyojellere bağlanmış ve daha sonra Zn2+ iyonları ile şelatlaştırılmıştır. Kriyojeller FTIR, SEM, EDX ve şişme çalışmaları ile karakterize edilmiştir. Bu kriyojeller 30-50 'm büyüklüğünde birbirine bağlı gözeneklere sahiptir. Zn2+ ile şelatlaştırılmış poli(HEMA-GMA)-IDA kriyojellerinin denge şişme derecesi yaklaşık % 600'dür. Zn2+ ile şelatlaştırılmı şpoli(HEMA-GMA)-IDA kriyojelleri sulu çözeltiden alkol dehidrogenaz adsorpsiyonu için kullanılmış ve adsorpsiyon sürekli sistemde gerçekleştirilmiştir. Adsorpsiyona pH, alkol dehidrogenaz derişimi, sıcaklık, iyonik şiddet ve akış hızının etkisi araştırılmıştır. Maksimum alkol dehidrogenaz miktarı, 1,0 mg/mL alkol dehidrogenaz derişiminde ve 0,5 mL/dak akış hızındaki pH 5,0 asetat tamponunda 9,94 mg/g polimer olarak bulunmuştur. Adsorplanan alkol dehidrogenazın desorpsiyonupH 8,0 fosfat tamponunda 1,0 M NaCl içerisinde gerçekleştirilmiş ve % 93,5 olarak bulunmuştur. Ayrıca bu kriyojeller tek bir adımda mayadan alkol dehidrogenaz saflaştırılmasında kullanılmıştır. Desorbe edilen alkol dehidrogenazın saflığı gümüş ile boyanmış SDS-PAGE ile gösterilmiştir. Bu saflaştırma işlemi ham maya homojenatından alkol dehidrogenaz enziminin saflaştırılması için başarılı bir şekilde kullanılabilir.In this thesis, poly(2-hydroxyethyl methacrylate-glycidyl methacrylate) [poly(HEMA-GMA)] cryogels were prepared by radical cryocopolymerization of HEMA with GMA as a fonctional comonomer and N,N'-methylene-bisacrylamide(MBAAm) as a crosslinker. Iminodiacetic acid (IDA) fonctional groups were attached via ring opening of the epoxy group on the poly(HEMA-GMA) cryogels and then Zn2+ ions were chealeted with this structures. Characterization of cryogels was performed by FTIR, SEM, EDX and swelling studies. These cryogels have interconnected pores of 30-50 µm size. The equilibrium swelling degree of Zn2+ chealeted poly(HEMA-GMA)-IDA cryogels was approximately 600%. Zn2+ chealeted poly(HEMA-GMA)-IDA cryogels were used in the adsorption of alcohol dehydrogenase from aqueous solutions and adsorption was performed in continuous system. The effects of pH, alcohol dehydrogenase concentration, temperature, ionic strengt hand flow rate on adsorption were investigated. The maximum amount of alcohol dehydrogenase adsorption wasd etermined to be 9,94 mg/g cryogel at 1,0 mg/mL alcohol dehyrogenase concentration and acetate buffer at pH 5,0 with flow rate of 0,5 mL/min. Desorption of adsorbed alcohol dehyrogenase was carried out by 1,0 M NaCI at pH 8,0 phosphate buffer and desorption rate was found to be 93,5 %. Additionally, these cryogels was used for purification of alcohol dehydrogenase from yeast with a single-step. The purity of desorbed alcohol dehydrogenase was shown by silver-stained SDS-PAGE. This purification process can successfully be used for the purification of alcohol dehydrogenase from unclarified yeast homogenates
Electrospun Polyurethane Nanofibers
The electrospinning process is highlighted with the ability of fabricating fibers with diameters on the nanometer scale, small inter-fibrous pore size and high porosity, vast possibilities for functionalization with high surface area to volume or mass ratio, ease of use and instrument setup, and adaptability. It attracted a great deal of attention due to its unique properties. More than 100 different polymers have been successfully electrospun into ultrafine fibers using this technique including synthetic polymers such as polyurethane (PU). Electrospun PU nanofiber mats exhibiting good mechanical properties may have a wide variety of potential applications in high-performance air filters, protective textiles, wound dressing materials, sensors, drug delivery, etc. This chapter deals with the electrospinning of polyurethane nanofibers and their potential applications
Termination of the teaching of the Continuous Cursive Handwriting in Schools
Handwriting is a skill that is a requirement for all individuals, however, there is a deep and decisive debate about whether or not the cursive handwriting is necessary in this era of technological innovations. While the necessity of compulsory cursive handwriting education is generally addressed by educators and politicians, there is no consensus on it, and the opinions of the people with interest or concern in education (e.g. teachers, students and parents) are not so often asked. For this reason, the aim of this study is to reveal the views of teachers, students and parents on the cursive handwriting education. 57 classroom teachers, 230 primary school fourth grade students and 14 parents participated in the study from four public primary schools in Ankara. Data were collected using ‘Personal Information Form’, ‘Cursive Handwriting Education Attitude Scale’, ‘Parent Questionnaire’ and ‘Student Questionnaire’. Quantitative data were analyzed using descriptive statistics techniques and qualitative data were analyzed by content analysis. According to the findings of the study, teachers and parents are not satisfied with the use of cursive handwriting. While teachers indicated that they would prefer print letters instruction if they had given a chance to choose. Parents affirmed that they could not give support to their children during their writing education. On the other hand, most of the students stated that they had difficulty in reading even their own handwritings, although most of them declared that they like to write with the cursive handwriting
Female murderers: Examination of the relationship between childhood traumatic experiences and anger expression
Adverse childhood period and abuse experiences may lead to some problems later in life. One of these problems is aggressive behavior, which is thought to be a reflection of the child’s increasing anger (Page, 2004; Olive, 2007). Based on the fact that negative childhood experiences can lead to aggressive emotions, investigating the relationship between traumatic childhood experiences and female convicts’ aggression expression styles was considered important.Sample of the research consists of 77 females who are homicide convicts selected from correctional institutes in three different cities. Data gathered from the participants were examined by using the Turkish versions of The Childhood Trauma Questionnaire and The State-Trait Anger Scale.A positive and meaningful relationship between childhood trauma experiences and trait anger levels of participants was observed. In addition, there was a significant relationship between childhood trauma experiences and domestic violence as well as perceived problematic relationship with family members during childhood. Trait anger and internal anger were also found to be significantly related to perceived problematic relationship with family members during childhood. Results of the analyses were discussed in detail
The Relationship between Eating Behaviors of Children and Mothers, and Nutritional Status of Children
Introduction:Â Parents have a significant impact on child nutrition and the child's eating habits in long-term behavior. This study aims to examine the effects of mothers' attitudes on the eating behaviors of children and the determination of their nutritional status.Method:Â Children's eating habits and mothers' eating attitudes were examined in 417 children with face-to-face interviews using the Child Feeding Questionnaire (CFQ). The participants' anthropometric characteristics were determined, and body mass indexes (kg/m2) were calculated. AnthroPlus software was used to determine the children's BMI-for-age Z-scores. BeBiS nutrition information system was used to assess children's food intake.Results:Â The mothers' median BMI was above the overweight threshold. The lowest CFQ score was for perceived child weight, and the maximum score was for food restriction. Significant differences were found in mothers ages, mothers' BMIs, children's WAZ and BAZ scores, and BMIs, weight (p<0.001), perceived parent weight scores (p=0.04), and pressure to eat (p=0.04). Families should be conscious about nutrition for the protection and promotion of children's health
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