Effects of different reaction mediums on ring opening polymerization of poly(ε-caprolactone) by lipase

This work examined the effects of reaction conditions on ring opening polymerization of poly(ε-caprolactone) (PCL) by Candida antarctica lipase B (Novozym 435) as the catalyst. Different reaction mediums were obtained by changing of temperature, reaction time and solvent types simultaneously. The main purpose of this study was to observe molecular weight distribution, conversion rates, and thermal behaviors of PCL and to find the highest molecular weight in enzymatic reaction conditions. Three different reaction temperatures and solvent types were studied in this work. Reactions were carried out at 40, 60 and 80°C and n-hexane, toluene and diisopropyl ether were used as solvents. One more reaction series were done for toluene solution at 30°C. Moreover, experiments were undertaken at seven different time periods. During all the reactions, monomer, solvent, and enzyme concentrations were not changed. For 1 ml monomer/solvent solution (0.44 M monomer and 0.56 M solvent), 10 mg lipase were used in the experiments. All samples were analyzed by gel permeation chromatography (GPC) and hydrogen nuclear magnetic resonance (1H-NMR) to obtain molecular weights, conversion rates, and chemical structures. Fourier transform infrared spectroscopy (FTIR) analysis was performed to determine chain structures of PCL samples. Thermal behaviors of samples were analyzed by differential scanning calorimetry (DSC) to examine and compare polymers with each other.Keywords: Candida antarctica lipase, enzymatic ring-opening polymerization, polycaprolactone, biopolymer

A Study About Effect Of Soil Model On Slope Under Vibration Load

This paper presents the effect of soil material model on slope under vibration loading. Ahard consistency clay is assumed within an example slope profile with the height of 10m andangle 25 for the evaluations. The linear elastic, Mohr-Coulomb and hardening soil modelsare considered using 2D finite element method by dynamic analysis. The results indicate that the velocities evaluated by the soil models are within the safety limits and accepted for the design. The soil models almost perform same values for factor of safety (not for linear elastic)and velocities. This study is believed to be beneficial for the applications in practice

Multifunctional and Stimuli-Responsive Polymersomes for Biomedical Applications

The demand for multifunctional nanocontainers possessing both recognition ability and responsive nature is increasing greatly because of their high potential in various biomedical applications. The engineering of such smart nanovesicles is useful to enhance the efficiency of many therapeutic and diagnostic tools that have the applicability in targeted drug delivery systems as well as designing sensing devices or conducting selective reactions as nanoreactors in the scope of nanobiotechnology. For this purpose, this study demonstrates the formation of multifunctional and stimuli-responsive polymersomes comprising various abilities including pH and light sensitivity as well as many reactive groups with sufficient accessibility to be used as smart and recognitive nanocontainers. The fabrication included several steps starting from the synthesis of azide and adamantane terminated block copolymers, which were then self-assembled to prepare the polymersomes with the corresponding functional groups for the subsequent post-conjugations at the vesicle periphery. The accessible and sufficiently reactive groups were quantitatively proven when UV and IR cleavable NVOC protected amino groups as well as β-cyclodextrin molecules were conjugated to the pre-formed polymersomes through click chemistry and strong host-guest complexations. The gained light responsivity with the aid of successful NVOC attachment enabled further selective photochemical reactions triggered either by UV or NIR light leading to liberated amine groups on the polymersome surface. Therein, these released amino groups were further conjugated with a model fluorescent compound as mimicking the attachment of biorecognition elements to see the direct picture of the applicability. To realize this concept in a more localized and selective way as well as to avoid the possible side effects of UV light, the NIR-light induced photochemical reactions and further dye coupling were performed when polymersomes were immobilized onto solid substrates. This fixation was achieved by adapting the host-guest chemistry into this part and conjugating the adamantane decorated polymersomes onto β-cyclodextrin coated substrates. Several investigations including adhesion behavior, pH sensitivity and mechanical properties of the established multifunctional polymersomes under liquid phase have been performed. It has been found that the polymersome shape is highly dependent on the attractive forces of the substrate and needs to be optimized to avoid the flattening of the vesicles. For these optimization steps, different conditions were investigated including the decrease of cyclodextrin amount and additional surface passivation with PEG molecules on the solid substrates. Besides, the calculated Young’s and bending modulus of the polymersome membrane from AFM measurements showed a robust but still flexible “breathable” membrane which is an important criterion for the applicability of these smart and stable vesicles. In addition, the hosting ability as well as diffusion limits and sufficient membrane permeability of the polymersomes were observed by encapsulating gold nanoparticles as a smart cargo and doxorubicin molecules as an anticancer drug. In conclusion, the established multifunctional polymersomes are highly versatile and thus present new opportunities in the design of targeted and selective recognition systems which is highly interesting for various applications including development of microsystem devices, design of chemo/biosensors, and also for conducting enhanced, combined therapy in the field of drug delivery

Synthesis Of Polycaprolactone Via Enzymatic Ring Opening Polymerization

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2011Bu çalışma, halkalı bir ester olan ε-kaprolakton monomerinden enzimatik halka açılması polimerizasyonu ile polikaprolakton eldesi üzerine odaklanmıştır. PCL sentezi, farklı taşıyıcılar üzerine immobilize edile enzimlerin katalizörlüğünde gerçekleştirilmiş, ve poliester sentezinde yeni biyokatalizörlerin geliştirilmesi üzerine yoğunlaşılmıştır. Bu amaçla, öncelikle polimerizasyon işlemi poliester sentez işlemlerinde sıklıkla kullanılan akrilik rezin üzerine immobilize edilmiş candida antarctica lipase B (CALB) enzimi kullanılarak gerçekleştirilmiştir. Ticari ismi ‘Novozym 435’ olan bu enzimin reaksiyonda yüksek performans göstermesine rağmen, pahalı olması ve taşıyıcı ile arasındaki bağın zayıflığı çözülmesi gereken bir sorun olarak göze çarpmaktadır. Bu nedenle çalışmanın ikinci kısmında, poliester sentezinde kullanılmak üzere lipaz enzimi farklı taşıyıcılar üzerine immobilize edilmiştir. Çalışmada, taşıyıcı malzeme olarak kitin ve kitosan doğal polimerleri seçilmiştir. Deneysel çalışmanın devamında lipaz enzimi kitin ve kitosan polimerleri üzerine fiziksel adsorpsiyon ve çapraz bağlanma olmak üzere iki farklı yöntem uygulanarak immobilize edilmiştir. Elde edilen enzimlerin performansı polimerizasyon işleminde değerlendirilmiştir. Sonuçta, çapraz bağlanma yöntemi ile immobilizasyon fiziksel adsorpsiyona göre daha etkili olmuştur. Çalışmanın son kısmında elde edilen immobilize enzimlerin etkinliği 60, 70 ve 80 oC olmak üzere üç farklı sıcaklıkta halka açılımı polimerizasyonunda değerlendirilmiştir. Elde edilen polimerlerin NMR ve FTIR analizleri ile yapısal karakterizasyonu yapılmış, DSC analizi ile ısıl özellikleri incelenmiştir. Ayrıca, sıcaklığın etkisi üretilen polimerlerin molekül ağırlıkları GPC analizi ile belirlenerek gözlenmiştir.This study focused on PCL synthesis via enzymatic ring opening polymerization of ɛ-CL. It was aimed to develop different immobilized enzymes for PCL synthesis. For this purpose, firstly polymerization reaction was performed with candida antarctica lipase B (CALB) enzyme immobilized on acrylic resin. This enzyme is available commercially (trade name: novozym 435) and often used for polyester synthesis. Although it can catalyze the reaction efficiently, high costs and enzyme leakage problem leads scientists to solve these negative sides of novozym 435. Due to this, in the second part of the study, different supports are used for CALB immobilization in order to obtain efficient catalysts for PCL synthesis. As support material for immobilization process, chitin and chitosan was chosen in this study. Furthermore, immobilization methods were performed by using two different techniques: physical adsorption and cross-linking with gluteraldehyde. Resulting immobilized catalysts were evaluated in polymerization reactions and immobilized lipases via cross-linking with gluteraldehyde were more efficient than physically adsorbed enzymes. This study was concluded with evaluation of immobilized enzymes at three different temperatures (60, 70 ve 80 oC) within a time range for ROP of ɛ-CL. Obtained polymers were characterized by 1H NMR and FTIR analysis. Furthermore, DSC analysis was applied in order to observe thermal behaviors and crystallinity of polymers. Molecular weights and polydispersities of obtained polymers were determined with GPC.Yüksek LisansM.Sc

Comparison of residual shear strength determined by different methods

The shear stress of stiff or dense soils increases with the displacement and reaches itsmaximum value, and then shear stress decreases and remains a constant value. The minimumand constant shear stress of soils reached at large shear displacements is called as residualshear strength. Residual shear strength generally has a great importance in design ofengineering structures constructed on fissured overconsolidated clays and long-term slopestability analysis in geotechnical engineering. In laboratory testing, modeling the residualconditions of a soil requires large shear displacements attained in drained conditions.Reversal direct shear test (RDS), consolidated-drained triaxial test (CD) and torsional ringshear test (RS) are the widely used testing methods to determine residual shear strengthparameters. These methods have some advantages or limitations when compared with eachother. In this study, residual shear strength parameters of soil samples having different clayfractions were determined by the three different drained tests, the results were compared, andeffect of the testing methods on residual shear strength was investigated. The variation ofresidual shear strength angle versus liquid limit and plasticity index were studied. The resultswere compared with previous studies. As a result, it is found that the residual shear strengthangle determined by the ring shear test is lower than the others, and the residual shear strengthangle decreases with the increasing liquid limit and plasticity index

Antibody-Functionalized Carnauba Wax Nanoparticles to Target Breast Cancer Cells

[Image: see text] Development of safer nanomedicines for drug delivery applications requires immense efforts to improve clinical outcomes. Targeting a specific cell, biocompatibility and biodegradability are vital properties of a nanoparticle to fulfill the safety criteria in medical applications. Herein, we fabricate antibody-functionalized carnauba wax nanoparticles encapsulated a hydrophobic drug mimetic, which is potentially interesting for clinical use due to the inert and nontoxic properties of natural waxes. The nanoparticles are synthesized applying miniemulsion methods by solidifying molten wax droplets and further evaporating the solvent from the dispersion. The pH-selective adsorption of antibodies (IgG1, immunoglobulin G1, and CD340, an antihuman HER2 antibody) onto the nanoparticle surface is performed for practical and effective functionalization, which assists to overcome the complexity in chemical modification of carnauba wax. The adsorption behavior of the antibodies is studied using isothermal titration calorimetry (ITC), which gives thermodynamic parameters including the enthalpy, association constant, and stoichiometry of the functionalization process. Both antibodies exhibit strong binding at pH 2.7. The CD340-decorated wax nanoparticles show specific cell interaction toward BT474 breast cancer cells and retain the targeting function even after 6 months of storage period

Effects of local soil conditions on dynamic response of trapezoidal valleys

Geoteknik deprem mühendisliğinde karşılaşılan en önemli problemlerden biri, zemin tabakalarının deprem sırasında gösterdiği davranışın belirlenmesidir. Bir sahada oluşan deprem hareketinin özellikleri tektonik yapı, kırılma mekanizması, doğrultu etkisi, merkez üstü uzaklığı, jeolojik yapının ve yerel zemin koşullarının etkisi gibi birçok faktöre bağlıdır. Zemin tabakalarının dinamik analizi için geliştirilen hesap yöntemleri bir, iki ve üç boyutlu olarak tanımlanmaktadır. İki ve üç boyutlu analizlerde, zemin kesitindeki tabakaların iki veya üç boyutlu geometrisi gerektiği için, bir boyutlu yaklaşımın kullanımı daha fazla tercih edilmektedir. Ancak zemin tabakalarının bir boyutlu dinamik analizinde; yüzey topografyası, tabakaların eğimi ve tabakaların sınırlı enine genişliğinin etkisi ihmal edilmektedir. Zemin tabakalarının yatay yönde sınırlı genişliğe sahip olması, vadi kenarlarında dalga hareketi dönüşümlerine sebep olmakta, dolayısıyla yer hareketinin frekans içeriği ve yüzeydeki etkisi vadilerin ortasından kenarlarına doğru değişebilmektedir. Bu çalışmada, seçilen trapez kesitli simetrik vadi modellerinde yerel zemin koşullarının zemin büyütmesine etkisi incelenmiştir. Bu amaçla, kenarlarda anakaya eğimi sabit olan, derinlik ve genişliği farklı vadi modelleri kullanılarak, farklı anakaya ivme kayıtları için bir ve iki boyutlu dinamik analizler yapılmış, elde edilen sonuçlar karşılaştırılmıştır. Her modelde zemin kesitinde en üstte kil tabakasının yer aldığı kabul edilmiştir. Yapılan analizler sonucunda, vadi yüzeyindeki ivme spektrumları, Afet Bölgelerinde Yapılacak Yapılar Hakkında Yönetmelik’te tanımlanan yerel zemin sınıfları için elde edilmiştir. Yüzeyde hesaplanan en büyük ivme değerleri, anakaya ivmelerine oranlanarak zaman ortamındaki zemin büyütmeleri elde edilmiş ve uzaklığa bağlı değişimleri incelenmiştir. Anahtar Kelimeler: Yerel zemin sınıfı, zemin büyütmesi, vadi modeli, dinamik analiz.One of the most commonly encountered problems in geotechnical earthquake engineering is the evaluation of ground response. The characteristics of ground motion at a particular site depend on many factors such as tectonics of the region, epicentral distance, geological formations, bedrock depth, geotechnical site conditions, local surface and subsurface topography. The topographical characteristics include the effects of surface formations, the two and three dimensional geometry of the subsurface soil layers and bedrock to the local site ground response. The calculation methods developed for the dynamic analysis of the soil layers are usually defined as two and three dimensional according to the necessity of the problem met. The two and three dimensional geometry of the soil layers and bedrock is required to perform two and three dimensional ground response analysis, so because of the application convenience one dimensional dynamic analysis is mostly preferred. However in one dimensional ground response analysis the surface topography, two or three dimensional geometry of the subsurface and the effects of the limited width of the soil layers are being neglected. In fact because of the limited lateral width of the soil layers wave transformations at the basin edges occur, surface waves are being focused to the valley center, two dimensional resonance models may occur and consequently the amplitude and frequency content of the ground motion may change from the center of the valley to the edges. In this paper, in order to study the effects of local site conditions, the depth and width of soil layers, the frequency content and amplitude of strong ground motion to the site amplification and frequency content of surface wave motion, one and two dimensional dynamic analyses were performed for five different bedrock acceleration records by using idealized trapezoidal symmetrical valley models. The results of the one and two dimensional analyses were compared, and the variations of the amplifications with the distance from the valley edges were investigated. These models have different depths and widths. In the valley models, the soil layers were assumed to extend horizontally limited with valley edges having a constant slope angle of 45°. The topsoil layer was selected as high plasticity clay for each model. The parameters such as the thickness and initial shear wave velocities of the soil layers above bedrock, which play the main role in the determination of dynamic response, were selected in accordance with the soil groups and soil classes defined in Turkish Earthquake Design Code (1998). With this aim, the valley models were subjected to 1D and 2D dynamic analyses by using five different bedrock strong ground motion records and the results were compared .The results that will be obtained from the 1D and 2D analyses were aimed to reflect the seismotectonical structure of the North Anatolian fault in Turkey. Therefore two bedrock acceleration time histories were selected among the Turkey earthquakes. The vertical and horizontal boundary conditions become important especially in the dynamic analyses of 2D models. In this study viscous dashpots, which are, calculated proportional to the shear and pressure waves of the relevant layers were put at the vertical and horizontal layers. High amplification values were calculated at the surface of rigid valley models having local site class of Z2. In the models having local site class of Z3 or Z4, the amplifications decreased at the high bedrock acceleration values. At the models with sudden rigidity change in the soil profile, the amplifications relatively increased for the surface sections, which are located at the beginning of valley edge (X/H=1). For the deeper valley models having a graded rigidity decrement from bottom to upper layers, the amplifications decreased noticeably and the increase in the peak bedrock acceleration values made this situation more remarkable. The bedrock topography must be carefully investigated to obtain the 2D dynamic behaviour of laterally limited soil layers under earthquake excitation. So the geological and geotechnical investigations should be done carefully to satisfy this condition. When the data about the topography of soil layers and bedrock is insufficient, it will be obligatory to prefer 1D dynamic analysis based upon the assumption of horizontal soil layers extending to infinity. However 1D and 2D dynamic analyses give similar results only for the sections near the middle part of very wide valleys. Keywords: Local site condition, soil amplification, valley model, dynamic analysis

Basin edge effect on dynamic response of soil layers: 1D and 2D behaviour

Surface geology and the geotechnical properties of near surface soil layers have important effects on the earthquake ground motion. Site effects can be defined as the variation in the characteristics of incoming wavefield such as amplitude, frequency content and duration because of the geotechnical, dynamic and geometrical properties of soil layers and surface topography. The main source of site effects is the specific impedance contrast between near surface and deep soil layers. The calculation methods which were developed for the dynamic analysis of soil layers are defined as one, two and three dimensional. In one dimensional approach the soil medium is assumed as horizontally layered for simplicity and the analyses are based on the principal of body waves travelling up and down in the near surface layers. However, in fact sedimentary deposits form mediums which can only be defined by 2 or 3 dimensional methods. This kind of deposits with lateral geological discontinuities show trap behaviour. This trap affects the surface waves which develop during earthquakes and reverberate back and forth on the interface of sediment deposit and bedrock. As a result, the amplitude of surface ground motions may show variation dependent on the site where it occurs, also the frequency content of this surface motion will differ from site to site at the edge of deep deposits. In this paper, two dimensional basin edge models with four different slope values (H/D=10, 5, 2, 1) were constituted to investigate the effects of basin edge on the variation of surface motion under earthquake excitations with different frequency content. Duzce basin  shear wave velocity profile, which had been obtained from the analyses of microtremor array and single point measurements, was used to form the two dimensional geometry of soil layers and bedrock in the basin edge models. One (1D) and two dimensional (2D) dynamic analyses were performed for six different bedrock acceleration records by using these basin edge models. The results which would be obtained from the 1D and 2D analyses were aimed to reflect the seismotectonical structure of the faults in Turkey. Therefore four bedrock acceleration time histories were selected among the Turkey earthquakes. In order to eliminate the "box effects" which can occur during the two dimensional dynamic finite element analyses because of the model geometry and boundary conditions; viscous dashpots, which are calculated proportional to the shear and pressure waves of the relevant layers, were put at the vertical and horizontal layers. Modified equivalent linear method and equivalent linear methods were used in the 1D and 2D analyses respectively. After performing 1D and 2D dynamic analyses on the models, the calculated results were compared. The variations of the soil amplifications and acceleration spectrum intensity (ASI) values with the distance from the valley edges were investigated. To understand the difference between 1D and 2D dynamic behaviours, the 2D/1D spectral acceleration ratios which are known as "aggravation factors", were calculated for different period values. Remarkable increase in soil amplification, ASI and aggravation factors was observed between the rock outcropping site and X/D=3 point at basin edges. The highest aggravation factor values were obtained at 0.2 sec-0.5 sec interval for all valley models, also especially for models with H/D= 2 and 1 these values reached to peak. Regardless of the periods considered, the aggravation factors generally converged to 1 after the points X/D=5, 4, 2, 1.5 for the basin models with H/D=10, 5, 2 and 1 respectively. The 2D effects were mostly becoming negligible after these points. After this, the acceleration time histories and absolute acceleration spectrums which had been evaluated for the different points on edge surface were considered statistically and the relation between the results of 1D and 2D dynamic analyses was investigated by calculating aggravation factors for different period values. After evaluating the aggravation factors for different periods statistically, an aggravation factor relation was defined for the basin edge models with different edge slope values. It was revealed that by using the 2D/1D aggravation factor relation, the limiting effect of the second dimension at basin edges can be reflected to the spectral accelerations evaluated from the results of one dimensional dynamic analysis, as a function of the distance from rock outcrop site and seismic bedrock depth. Also the X/D values, which the aggravation factors can be neglected after, were determined. Keywords: 1D and 2D dynamic analysis, aggravation factor, ASI, basin edge effect.Deprem sırasında oluşan yer hareketinin genliğinde, frekans içeriğinde ve süresinde incelenen bölgeye bağlı meydana gelen değişimlere “yerel etkiler” denir. Yerel etkiler; başlıca, yüzeydeki zemin tabakalarıyla daha altta yer alan anakaya arasındaki özgül direnç farklılığından kaynaklanmakla birlikte, ova/vadi gibi derin oluşumlar ile bunların kenarlarında yanal jeolojik süreksizlikler tarafından meydana getirilen etkileri de kapsar. Yanal süreksizliklere sahip bu tür ortamlarda zemin tabakalarının yatay yönde sınırlı genişliğe sahip olması, vadi kenarlarında dalga hareketi dönüşümlerine sebep olmakta ve kuvvetli yer hareketinin süresi uzayabilmektedir. Bu tip durumlarda, yüzeydeki hareketin genliği ova/vadi üzerinde elde edildiği bölgeye göre değişim gösterecek ve frekans muhtevası aynı bölgede bir boyutlu analizle hesaplanana göre farklılaşabilecektir. Bu çalışmada, iki boyutlu kayma dalgası hızı profili geniş açıklıklı eş zamanlı mikrotremor ağ ve tekil mikrotremor ölçümleriyle belirlenmiş olan Düzce Ovası modelinde, kenardaki anakaya eğiminin değişmesi halinde farklı frekans içeriğine sahip deprem hareketleri karşısında  yüzey hareketinin nasıl etkileneceği anlaşılmaya çalışılmıştır. Bu amaçla, modellerde farklı noktalar için bir (1D) ve iki boyutlu (2D) dinamik analizler yapılmış, ova kenarındaki zemin büyütmelerinin ve şiddet parametrelerinin geometriye bağlı değişimi incelenmiş, ova kenarındaki kısımlar için 2D/1D spektral ivme oranları (şiddet faktörleri) hesaplanmıştır. Farklı periyotlar için hesaplanan bu değerlerin istatistiksel açıdan değerlendirilmesiyle, farklı anakaya eğimine sahip modeller için ova kenarındaki anakaya mostrasından olan uzaklığa ve sismik anakaya derinliğine bağlı şiddet faktörü ilişkisi tanımlanmış ve bir boyutlu dinamik analizin yaklaşık geçerlilik sınırları belirlenmiştir. Anahtar Kelimeler: 1D ve 2D dinamik analiz, kenar etkisi, şiddet faktörü, yerel etkiler, zemin büyütmesi

Zemin büyütmesi ve yerel koşulların spektral ivmeye etkisi

One of the most commonly encountered problems in geotechnical earthquake engineering is the evaluation of soil amplification. Soil amplification can be defined as the increase in the amplitudes of the earthquake waves. Soil amplification is mostly affected by the local soil conditions such as bedrock depth, the thickness and dynamic characteristics of the soil layers, the limited width of the soil layers and the topographical properties. The variation of ground motion is denoted as an amplification or de-amplification of amplitudes at all frequencies, which is dependent on many parameters. Some of them are inherent of the dynamic soil behavior and its physical properties such as shearing modulus, damping ratio, shear wave velocity, plasticity index etc., and others are related to the characteristics and the intensity of the incoming wave-field, geometrical features like surface/bedrock topography, lateral geological discontinuities etc. Site effects play an important role in the variation of ground motion intensity distribution during earthquakes and therefore they have to be evaluated correctly for the design of earthquake resistant buildings. In this study, in order to investigate the effects of the local soil conditions to the soil amplification, an idealized simple model consisting of a crest and basin geometry was selected. One (1D) and two-dimensional (2D) dynamic analyses were performed for the two different cases of the top basin layer as high plasticity clay and silty sand, and the obtained results were compared. Six bedrock acceleration records with different frequency content were used in the dynamic analyses. Within the scope of this study, EERA and Flushplus softwares were used in the 1D and 2D dynamic nonlinear dynamic analyses, respectively. Flushplus is a finite element dynamic analysis software that is based on equivalent linear method and it works in the frequency domain. Viscous dashpots that were calculated proportional to the shear and pressure waves of the relevant layers were set at the boundaries of vertical and horizontal layers in the 2D model. The variations of the soil amplifications with the surface geometry were investigated by the 1D and 2D dynamic analyses. The 2D/1D spectral acceleration ratios were calculated for different period values at the lowland and highland regions of the 2D model in order to understand the difference between 1D and 2D dynamic behaviors. It was understood that the peak acceleration value of the bedrock ground motion was amplified by twice in case the top basin layer was selected as silty sand and the soil amplification value reached to 4.5 for the case of top basin layer as high plasticity clay. When the top soil layer was high plasticity clay, the 2D/1D spectral acceleration ratios reached their maximum values for high frequencies at the basin edge section where X/D is between 0.5 and 0.75, while X indicates the horizontal distance and D is the depth. As approaching to the mid part of the basin, 2D/1D spectral acceleration ratios reached their maximum values at lower frequencies because of the wave transformations that occur at basin edges.  The difference between the results of 1D and 2D dynamic analyses decreased for higher frequencies with the increasing distance from the edge of the basin. When the top layer was selected as sand, the 2D/1D spectral acceleration ratios showed similar behavior for the lower frequencies, but an increase in the 2D/1D values was noticed at higher frequencies mainly for the sections 0.75Because of the limited width of the soil layers in basin and vertical boundary conditions, the 2D predominant period of the model took a lower value when compared with the results of 1D dynamic analysis. As a result the spectral acceleration values obtained by the 2D dynamic analyses were different from the spectral acceleration values calculated by 1D dynamic analysis especially at higher frequencies. The peak surface acceleration values that were calculated by the 2D analyses approached to each other regardless of the basin geometry when the non-linear behavior became dominant at the top layers. Topographical effects were negligible for very low frequencies, while the effects became significant for high frequencies or low wavelengths comparable to the geometric characteristics of the model. The intensity of the bedrock acceleration and the variation of dynamic properties with soil type play an important role in the development of non-linear dynamic behavior. Keywords: Soil amplification, local conditions, 2D dynamic analysis, spectral acceleration ratio.Bir sahada yerel koşullara bağlı olarak oluşabilecek zemin büyütmesinin belirlenmesi, geoteknik deprem mühendisliğinin önemli konularından birini oluşturmaktadır.  Anakaya seviyesinde bir kaynaktan açığa çıkan enerjinin oluşturduğu sismik dalgalar yayılımları sırasında, içinden geçtikleri ortamların özelliklerinden etkilenmekte; süre, frekans ve genliklerinde değişimler olabilmektedir. Deprem dalgalarının yüzeye yakın zemin tabakaları içinden geçerken genliklerinde meydana gelen artış zemin büyütmesi olarak tanımlanmaktadır. Zemin büyütmesi anakaya derinliği, zemin tabakalarının kalınlığı, cinsi ve dinamik özellikleri, tabakaların yanal süreksizliği ve topografik özellikler gibi yerel koşullardan etkilenmektedir. Bu çalışmada, yerel koşulların zemin büyütmesine etkisini incelemek amacıyla tepe ve ovadan oluşan bir model seçilmiş, ova bölgesinde zemin kesitinin en üstünde yüksek plastisiteli kil ve siltli kum tabakasının olması durumu için, altı anakaya depremi kullanılarak bir (1D) ve iki boyutlu(2D) dinamik analizler yapılmıştır.  Yüzeyde 19 farklı noktada farklı depremler için elde edilmiş ivme zaman geçmişleri ve ivme spektrumlarının mesafeye bağlı değişimleri incelenmiştir. Anakaya ivmelerinin, üst tabakanın kum olması durumunda zemin yüzeyinde ortalama iki kat, üst tabakanın kil olması durumunda ise daha fazla arttığı belirlenmiştir. Üst tabakanın kil olması hali için özellikle anakaya dalımının ova tabanına ulaştığı bölgenin izdüşümünde yer alan kesimlerde, spektral ivme oranlarının yüksek frekanslarda en büyük değerini aldığı, ova ortasına doğru 1D ve 2D analiz sonuçları arasındaki farkın azaldığı belirlenmiştir. 1D analizlerde sonlu farklar yöntemine dayanan, eşdeğer lineer malzeme modeli ile çalışan EERA yazılımı, 2D analizlerde ise frekans ortamında çalışan Flushplus sonlu elemanlar programı kullanılmıştır. Anahtar Kelimeler: Zemin büyütmesi, zemin koşulları, 2D dinamik analiz, spektral ivme oranı

Toward Functional Synthetic Cells: In-Depth Study of Nanoparticle and Enzyme Diffusion through a Cross-Linked Polymersome Membrane

Understanding the diffusion of nanoparticles through permeable membranes in cell mimics paves the way for the construction of more sophisticated synthetic protocells with control over the exchange of nanoparticles or biomacromolecules between different compartments. Nanoparticles postloading by swollen pH switchable polymersomes is investigated and nanoparticles locations at or within polymersome membrane and polymersome lumen are precisely determined. Validation of transmembrane diffusion properties is performed based on nanoparticles of different origin—gold, glycopolymer protein mimics, and the enzymes myoglobin and esterase—with dimensions between 5 and 15 nm. This process is compared with the in situ loading of nanoparticles during polymersome formation and analyzed by advanced multiple-detector asymmetrical flow field-flow fractionation (AF4). These experiments are supported by complementary i) release studies of protein mimics from polymersomes, ii) stability and cyclic pH switches test for in polymersome encapsulated myoglobin, and iii) cryogenic transmission electron microscopy studies on nanoparticles loaded polymersomes. Different locations (e.g., membrane and/or lumen) are identified for the uptake of each protein. The protein locations are extracted from the increasing scaling parameters and the decreasing apparent density of enzyme-containing polymersomes as determined by AF4. Postloading demonstrates to be a valuable tool for the implementation of cell-like functions in polymersomes