하상고 차이가 있는 하천합류부에서 오염물질 혼합거동에 대한 수치모델링

학위논문(박사) -- 서울대학교대학원 : 공과대학 건설환경공학부, 2022. 8. 서일원.하천합류부는 서로 다른 수리학적 특성을 가지는 두 개 이상의 하천이 하나로 합쳐지는 구간으로 급격한 흐름변화 및 수리학적 변화가 발생하며 하천수질 및 생태계에서도 중요한 역할을 한다. 합류수로에서의 유동특성을 다룬 연구는 많은 연구자들에 의해 꾸준히 이어져 왔으나, 대부분의 연구가 전단층, 재순환구역 등 합류부의 독특한 특성들에 영향을 주는 주요인자들을 파악하는데 초점을 두었다. 하지만 실제 자연하천에서는 준설작업 등으로 인한 하상고의 불일치, 홍수 등으로 인한 본류와 지류의 급격한 유량 변화 등 합류부의 흐름특성이 변화하는 경우는 빈번히 발생한다. 또한 이로인한 이차류의 발생 및 이차류강도의 변화는 합류부에서의 흐름 및 오염물 혼합의 3차원 거동을 더욱 강화시킨다. 따라서 기존의 연구들과 같이 일부 지점에서 계측된 한정적인 데이터들로는 합류부의 전체적인 특성을 정확하게 파악하기 매우 어렵다. 이런 이유로 본 연구에서는 합류부에서의 흐름특성 및 오염물의 혼합거동을 종합적으로 이해하기 위해 지류가 90°로 유입되는 합류수로에서 단차비와 유량비를 변화시키며 3차원 수치모의를 수행하였고 실내합류수로실험을 통해 획득한 유속자료를 통해 모의결과를 검증하였다. 흐름장 모의 결과, 유량비와 단차비가 증가할수록 재순환구역의 최대 폭은 증가하는 것을 확인할 수 있었다. 반면 최대 길이는 단차비가 증가하면 길어지지만 유량비가 증가하면 짧아지는 경향을 보였다. 유량비와 단차비가 증가할수록 시계방향으로 회전하는 와류가 점차 발달하는 것을 확인하였으며 유량비와 단차비에 의해 강화된 이차류가 합류부의 흐름 및 오염물의 혼합에 큰 영향을 미치는 것을 확인하였다. 이러한 경향을 정량적으로 평가하기 위해 이차류강도 (SCI)를 계산해 본 결과, 단차비와 유량비가 증가할수록 합류 후 수로의 이차류강도가 증가하는 것을 알 수 있었으며 특히, 단차비가 증가함에 따라 이차류의 영향이 하류 방향으로 긴 구간에 걸쳐 지속되는 것을 확인하였다. 농도장 모의 결과, 유량비와 단차비가 증가함에 따라 횡방향 혼합이 빠르게 완료되는 것을 확인하였다. 특히, 단차비가 큰 경우 지류의 수체가 본류수로의 반대편 제방과 부딛치며 반사되는데 이 경우 주수로의 우측하단에서 좌측상단 방향으로 오염물 혼합이 진행되는 것을 확인하였다. 3차원 수치모의을 통해 파악한 흐름특성을 기준으로 모의구간을 흐름변화구간, 흐름분리구간, 흐름회복구간으로 구분하였으며 이들 구역에서 속도기반 및 농도기반 분산계수산정법 통해 횡분산계수를 계산하였다. 본 연구에서 횡방향 분산계수를 산정한 이유는 합류부에서 오염물의 혼합거동을 2차원 이송분산모형을 이용하여 빠르고 정확하게 모의하기 위함이며 실제로 자연하천의 합류부에서 지류를 통해 유입되는 오염물의 경우 합류직후 짧은 구간에서 3차원거동을 보이지만 연직방향 혼합이 완료된 이후에는 긴 구간에서 걸쳐 횡방향, 종방향으로 2차원 거동을 보이기 때문에 계산의 효율성이나 정확도를 고려하였을 때 2차원 수치모형을 사용하는 것이 바람직하다고 할 수 있다. 합류부에서 2차원 이송분산모형을 적용하는 경우 가장 중요한 매개변수는 분산 계수인데 분산계수 산정시 합류부의 복잡한 특성을 반영하지 못한다면 오염물질의 횡분산을 과대산정하거나 과소 산정하는 결과가 나타난다. 본 연구에서는 흐름특성이 다른 합류부 특성구간 별 적절한 분산계수를 계산하는 2D 분산모형을 제안하였다. 본 연구에서 제안하는 2D분산모형의 검증을 위해 낙동강-금호강 합류부에서 수행한 자연추적자실험의 지형자료, 유속 및 전기전도도 자료를 사용하였으며 수치모의를 위해 2차원수치모형 RAMS+를 이용하였다. 수치모의 결과 전체모의구간에 동일한 분산계수를 적용하는 기존의 모의방법에 비해 본 연구에서 제안한 새로운 분산모형을 사용하는 경우 합류직후 뿐만 아니라 합류 후 긴 모의구간에서도 높은 정확도를 보이는 계산 결과를 도출하였다.A river confluence is an essential topographical node that occurs at the junction of two or more separate flowing channels, resulting in complex hydraulic and morphological changes and controlling the downstream flow paths and mixing of contaminants. In addition, given that the confluence is common in natural large and small rivers and an inevitable feature of river systems, understanding river flow dynamics and contaminant transport at confluence channels is the topic of river engineers garnered significant research interest. Several studies have been conducted on the flow characteristics of the confluence channel since about 80 years ago, most of the studies had focused on the relationship of unique characteristics, such as shear layers, flow recirculation zone (RZ), and flow deflection zone with the confluence’s plane symmetry, angle, discharge rate, and momentum flux ratio. However, flow and pollutant mixing characteristics at the confluence are three-dimensional behaviors, and in particular, as the discharge or discordance ratios changes, the effect of reinforced secondary flows dramatically affects the characteristics of flow and contaminants mixing. So, it is difficult to grasp the features of the confluence channel accurately with data obtained piecewise through traditional methods. Therefore, in this study, three-dimensional (3D) numerical simulation was performed under various conditions to understand the 3D behavior at the confluence channel comprehensively. Through 3D numerical simulation, it was identified that the direction and magnitude of the lateral flow fluctuated abruptly with the streamwise direction and changes in discharge and discordance ratios affect the dimension of the RZ. It was confirmed that the maximum width of the RZ increased as the discharge and discordance ratios increased. The maximum length increased as the discordance ratio increased but shortened as the discharge ratio increased. It also confirmed that clockwise vortices strengthened as the discharge and discordance ratios increased. To evaluate this trend quantitatively, secondary current intensity (SCI) was calculated, revealing that the secondary flow dimensions in the post-confluence channel increased as the discharge and discordance ratios increased. In addition, as the step ratio increased, the secondary flow sustained its effect over a long section in the downstream direction. The results of the pollutant simulation confirmed the occurrence of rapid lateral mixing as the discharge and discordance ratios increased. Especially, when the discordance ratio was large, the waterbody of the tributary lashed the opposite bank of the main channel and was reflected. In these cases, pollutants began to mix from the right-bottom of the main channel, and the mixing proceeded in the opposite direction of the inflow from the tributary channel. Through the findings of 3D numerical simulation, the confluence channel was divided into specific zones based on flow characteristics. In these zones, the dispersion coefficient was calculated through velocity- and concentration-based methods and confirmed that the transverse dispersion coefficient was distributed differently in each section. The 3D numerical simulation was conducted first before applying the 2D dispersion model in this study because the effect of secondary flows, etc., which play an important role in mixing contaminants at the confluence cannot be identified through the 2D model. In addition, since it is inefficient to use a 3D model when simulating the mixture of contaminants in the confluence, it is intended to quickly and accurately simulate by using a 2D dispersion coefficient reflecting the confluence characteristics. In practice, three-dimensional simulations are not often used to determine the mixing characteristics of contaminants in the long section of the confluence. When simulating the mixed behavior of pollutants introduced through tributaries, it is reasonable to use a two-dimensional advection-dispersion model to satisfy both the efficiency of the calculation and the accuracy of the simulation. But if the dispersion coefficient, the most important parameter in the two-dimensional advection-dispersion model, does not reflect the complex flow and mixing behavior at the confluence, the transverse dispersion cannot be simulated appropriately immediately after the confluence. In addition, if the same dispersion coefficient is applied throughout the simulated section at the confluence where the flow characteristics change from three dimensions to two dimensions, the lateral dispersion of the contaminant is overestimated or underestimated. Therefore, in this work, a new 2D dispersion model was proposed. First, the characteristic sections are divided by analyzing the flow characteristics identified through the 3D numerical model, and a new 2D dispersion coefficient using the discharge and discordance ratio as the main factor is applied to each section. The newly proposed empirical equation showed the remarkable effect of the discordance and discharge ratios on the transverse dispersion coefficient. The dispersion coefficient equation, which reflected the influence of the discharge and discordance ratios, yielded more accurate results than using other hydraulic parameters.Abstract of dissertation Ⅰ List of figures Ⅸ List of tables ⅩⅢ List of symbols ⅩⅤ 1. Introduction 1 1.1 Background and Necessities 1 1.2 Objectives and Methodology 7 2. Theoretical Background 10 2.1 Flow Characteristics at River Confluence 10 2.1.1 Flow Dynamics at River Confluence 10 2.1.2 Division of Flow Zones of River Confluence 14 2.1.3 Secondary Flow at Channel Confluence 19 2.1.4 Flow Controlling Factors at Confluence 23 2.1.5 Discordance of channel bed 25 2.2 Modeling Pollutant Transport at River Confluences 28 2.2.1 Mixing Characteristics at River Confluences 28 2.2.2 Numerical Modeling of Contaminant Transport at River Confluences 31 2.2.3 Dispersion Coefficients 39 2.2.3.1 Caluculation of Velocity-based Dispersion Coefficiens 39 2.2.3.2 Caluculation of Concentration-based Dispersion Coefficiens 44 3. Numerical Models 49 3.1 Numerical Model Strategy 49 3.2 3D Numerical Model 51 3.2.1 Governing Equations 51 3.2.2 Turbulence Models 55 3.3 2D Numerical Model 59 3.3.1 2D Hydrodynamic Model 59 3.3.2 2D Advection Dispersion Model 62 4. Three-dimensional Simulation of Flow and Mixing at Channel Confluence 66 4.1 Objectices of 3D Numerical Simulation 66 4.2 Experimental Data for Verification 68 4.2.1 Laboratory Confluence Channel and Experimental Equipment 68 4.2.2 Analysis of Experimental Data 73 4.3 Three-dimensional Numerical Simulation Setup 78 4.3.1 Computational Domain and Grid Sensitivity Analysis 78 4.3.2 Turbulence Model and Input Parameters 83 4.3.3 Simulation Cases 87 4.3.4 Validation of 3D Numerical Simulation 91 4.4 Analysis of Flow Dynamics 101 4.4.1 Analysis of Flow-field 101 4.4.1.1 Velocity Field 101 4.4.1.2 Flow Recirculation Zone 111 4.4.1.3 Turbulent Characteristics 117 4.4.2 Analysis of Secondary Flow 122 4.4.2.1 Characteristics of Secondary Flow 122 4.4.2.2 Analysis of Intensity of Secondary Flow 128 4.5 Analysis of Contaminant Mixing 133 4.5.1 Concentration Field 133 4.5.2 Transverse Mixing 139 4.5.2.1 Concentration Contour on y-z plane 139 4.5.2.2 Analysis of Transverse Concentration Gradient 144 5. Estimation of Dispersion Coefficients 149 5.1 Division of Mixing Zone 151 5.2 Velocity-based Transverse Dispersion Coefficients 154 5.2.1 Calculation Methods 154 5.2.2 Results of Velocity-based Dispersion Coefficients 155 5.2.2.1 Dispersion Coefficients in Zone 1 (FDZ) 155 5.2.2.2 Dispersion Coefficients in Zone 2 (FSZ) 160 5.2.2.3 Dispersion Coefficients in Zone 3 (FRZ) 164 5.3 Concentration-based Transverse Dispersion Coefficients 169 5.3.1 Calculation of Dispersion Coefficients from Concentration Data 169 5.3.2 Comparison of Velocity-based and Concentration-based Dispersion Coefficients 176 6. Two-dimensional Model Application 180 6.1 Field Experiment Data 180 6.1.1 Study Site 180 6.1.2 Data Acquisition 183 6.1.3 Experimental Setup 186 6.1.4 Analysis of Velocity Data 188 6.1.5 Analysis of EC Data 193 6.2 Application of 2D Flow Model 196 6.2.1 Reflection of Study Site Characteristics 196 6.2.2 Sensitivity Analysis and Model Application 198 6.3 Application of 2D Mixing Model 204 7. Conclusion and Future study 211 7.1 Conclusions 211 7.2 Future Study 214 References 215 국문초록 223박

Architecture and algorithms for the implementation of digital wireless receivers in FPGA and ASIC: ISDB-T and DVB-S2 cases

[EN] The first generation of Terrestrial Digital Television(DTV) has been in service for over a decade. In 2013, several countries have already completed the transition from Analog to Digital TV Broadcasting, most of which in Europe. In South America, after several studies and trials, Brazil adopted the Japanese standard with some innovations. Japan and Brazil started Digital Terrestrial Television Broadcasting (DTTB) services in December 2003 and December 2007 respectively, using Integrated Services Digital Broadcasting - Terrestrial (ISDB-T), also known as ARIB STD-B31. In June 2005 the Committee for the Information Technology Area (CATI) of Brazilian Ministry of Science and Technology and Innovation MCTI approved the incorporation of the IC-Brazil Program, in the National Program for Microelectronics (PNM) . The main goals of IC-Brazil are the formal qualification of IC designers, support to the creation of semiconductors companies focused on projects of ICs within Brazil, and the attraction of semiconductors companies focused on the design and development of ICs in Brazil. The work presented in this thesis originated from the unique momentum created by the combination of the birth of Digital Television in Brazil and the creation of the IC-Brazil Program by the Brazilian government. Without this combination it would not have been possible to make these kind of projects in Brazil. These projects have been a long and costly journey, albeit scientifically and technologically worthy, towards a Brazilian DTV state-of-the-art low complexity Integrated Circuit, with good economy scale perspectives, due to the fact that at the beginning of this project ISDB-T standard was not adopted by several countries like DVB-T. During the development of the ISDB-T receiver proposed in this thesis, it was realized that due to the continental dimensions of Brazil, the DTTB would not be enough to cover the entire country with open DTV signal, specially for the case of remote localizations far from the high urban density regions. Then, Eldorado Research Institute and Idea! Electronic Systems, foresaw that, in a near future, there would be an open distribution system for high definition DTV over satellite, in Brazil. Based on that, it was decided by Eldorado Research Institute, that would be necessary to create a new ASIC for broadcast satellite reception. At that time DVB-S2 standard was the strongest candidate for that, and this assumption still stands nowadays. Therefore, it was decided to apply to a new round of resources funding from the MCTI - that was granted - in order to start the new project. This thesis discusses in details the Architecture and Algorithms proposed for the implementation of a low complexity Intermediate Frequency(IF) ISDB-T Receiver on Application Specific Integrated Circuit (ASIC) CMOS. The Architecture proposed here is highly based on the COordinate Rotation Digital Computer (CORDIC) Algorithm, that is a simple and efficient algorithm suitable for VLSI implementations. The receiver copes with the impairments inherent to wireless channels transmission and the receiver crystals. The thesis also discusses the Methodology adopted and presents the implementation results. The receiver performance is presented and compared to those obtained by means of simulations. Furthermore, the thesis also presents the Architecture and Algorithms for a DVB-S2 receiver targeting its ASIC implementation. However, unlike the ISDB-T receiver, only preliminary ASIC implementation results are introduced. This was mainly done in order to have an early estimation of die area to prove that the project in ASIC is economically viable, as well as to verify possible bugs in early stage. As in the case of ISDB-T receiver, this receiver is highly based on CORDIC algorithm and it was prototyped in FPGA. The Methodology used for the second receiver is derived from that used for the ISDB-T receiver, with minor additions given the project characteristics.[ES] La primera generación de Televisión Digital Terrestre(DTV) ha estado en servicio por más de una década. En 2013, varios países completaron la transición de transmisión analógica a televisión digital, la mayoría de ellas en Europa. En América del Sur, después de varios estudios y ensayos, Brasil adoptó el estándar japonés con algunas innovaciones. Japón y Brasil comenzaron a prestar el servicio de Difusión de Televisión Digital Terrestre (DTTB) en diciembre de 2003 y diciembre de 2007 respectivamente, utilizando Radiodifusión Digital de Servicios Integrados Terrestres (ISDB-T), también conocida como ARIB STD-B31. En junio de 2005, el Comité del Área de Tecnología de la Información (CATI) del Ministerio de Ciencia, Tecnología e Innovación de Brasil - MCTI aprobó la incorporación del Programa CI-Brasil, en el Programa Nacional de Microelectrónica (PNM). Los principales objetivos de la CI-Brasil son la formación de diseñadores de CIs, apoyar la creación de empresas de semiconductores enfocadas en proyectos de circuitos integrados dentro de Brasil, y la atracción de empresas de semiconductores interesadas en el diseño y desarrollo de circuitos integrados. El trabajo presentado en esta tesis se originó en el impulso único creado por la combinación del nacimiento de la televisión digital en Brasil y la creación del Programa de CI-Brasil por el gobierno brasileño. Sin esta combinación no hubiera sido posible realizar este tipo de proyectos en Brasil. Estos proyectos han sido un trayecto largo y costoso, aunque meritorio desde el punto de vista científico y tecnológico, hacia un Circuito Integrado brasileño de punta y de baja complejidad para DTV, con buenas perspectivas de economía de escala debido al hecho que al inicio de este proyecto, el estándar ISDB-T no fue adoptado por varios países como DVB-T. Durante el desarrollo del receptor ISDB-T propuesto en esta tesis, se observó que debido a las dimensiones continentales de Brasil, la DTTB no sería suficiente para cubrir todo el país con la señal de televisión digital abierta, especialmente para el caso de localizaciones remotas, apartadas de las regiones de alta densidad urbana. En ese momento, el Instituto de Investigación Eldorado e Idea! Sistemas Electrónicos, previeron que en un futuro cercano habría un sistema de distribución abierto para DTV de alta definición por satélite en Brasil. Con base en eso, el Instituto de Investigación Eldorado decidió que sería necesario crear un nuevo ASIC para la recepción de radiodifusión por satélite, basada el estándar DVB-S2. En esta tesis se analiza en detalle la Arquitectura y algoritmos propuestos para la implementación de un receptor ISDB-T de baja complejidad y frecuencia intermedia (IF) en un Circuito Integrado de Aplicación Específica (ASIC) CMOS. La arquitectura aquí propuesta se basa fuertemente en el algoritmo Computadora Digital para Rotación de Coordenadas (CORDIC), el cual es un algoritmo simple, eficiente y adecuado para implementaciones VLSI. El receptor hace frente a las deficiencias inherentes a las transmisiones por canales inalámbricos y los cristales del receptor. La tesis también analiza la metodología adoptada y presenta los resultados de la implementación. Por otro lado, la tesis también presenta la arquitectura y los algoritmos para un receptor DVB-S2 dirigido a la implementación en ASIC. Sin embargo, a diferencia del receptor ISDB-T, se introducen sólo los resultados preliminares de implementación en ASIC. Esto se hizo principalmente con el fin de tener una estimación temprana del área del die para demostrar que el proyecto en ASIC es económicamente viable, así como para verificar posibles errores en etapa temprana. Como en el caso de receptor ISDB-T, este receptor se basa fuertemente en el algoritmo CORDIC y fue un prototipado en FPGA. La metodología utilizada para el segundo receptor se deriva de la utilizada para el re[CA] La primera generació de Televisió Digital Terrestre (TDT) ha estat en servici durant més d'una dècada. En 2013, diversos països ja van completar la transició de la radiodifusió de televisió analògica a la digital, i la majoria van ser a Europa. A Amèrica del Sud, després de diversos estudis i assajos, Brasil va adoptar l'estàndard japonés amb algunes innovacions. Japó i Brasil van començar els servicis de Radiodifusió de Televisió Terrestre Digital (DTTB) al desembre de 2003 i al desembre de 2007, respectivament, utilitzant la Radiodifusió Digital amb Servicis Integrats de (ISDB-T), coneguda com a ARIB STD-B31. Al juny de 2005, el Comité de l'Àrea de Tecnologia de la Informació (CATI) del Ministeri de Ciència i Tecnologia i Innovació del Brasil (MCTI) va aprovar la incorporació del programa CI Brasil al Programa Nacional de Microelectrònica (PNM). Els principals objectius de CI Brasil són la qualificació formal dels dissenyadors de circuits integrats, el suport a la creació d'empreses de semiconductors centrades en projectes de circuits integrats dins del Brasil i l'atracció d'empreses de semiconductors centrades en el disseny i desenvolupament de circuits integrats. El treball presentat en esta tesi es va originar en l'impuls únic creat per la combinació del naixement de la televisió digital al Brasil i la creació del programa Brasil CI pel govern brasiler. Sense esta combinació no hauria estat possible realitzar este tipus de projectes a Brasil. Estos projectes han suposat un viatge llarg i costós, tot i que digne científicament i tecnològica, cap a un circuit integrat punter de baixa complexitat per a la TDT brasilera, amb bones perspectives d'economia d'escala perquè a l'inici d'este projecte l'estàndard ISDB-T no va ser adoptat per diversos països, com el DVB-T. Durant el desenvolupament del receptor de ISDB-T proposat en esta tesi, va resultar que, a causa de les dimensions continentals de Brasil, la DTTB no seria suficient per cobrir tot el país amb el senyal de TDT oberta, especialment pel que fa a les localitzacions remotes allunyades de les regions d'alta densitat urbana.. En este moment, l'Institut de Recerca Eldorado i Idea! Sistemes Electrònics van preveure que, en un futur pròxim, no hi hauria a Brasil un sistema de distribució oberta de TDT d'alta definició a través de satèl¿lit. D'acord amb això, l'Institut de Recerca Eldorado va decidir que seria necessari crear un nou ASIC per a la recepció de radiodifusió per satèl¿lit. basat en l'estàndard DVB-S2. En esta tesi s'analitza en detall l'arquitectura i els algorismes proposats per l'execució d'un receptor ISDB-T de Freqüència Intermèdia (FI) de baixa complexitat sobre CMOS de Circuit Integrat d'Aplicacions Específiques (ASIC). L'arquitectura ací proposada es basa molt en l'algorisme de l'Ordinador Digital de Rotació de Coordenades (CORDIC), que és un algorisme simple i eficient adequat per implementacions VLSI. El receptor fa front a les deficiències inherents a la transmissió de canals sense fil i els cristalls del receptor. Esta tesi també analitza la metodologia adoptada i presenta els resultats de l'execució. Es presenta el rendiment del receptor i es compara amb els obtinguts per mitjà de simulacions. D'altra banda, esta tesi també presenta l'arquitectura i els algorismes d'un receptor de DVB-S2 de cara a la seua implementació en ASIC. No obstant això, a diferència del receptor ISDB-T, només s'introdueixen resultats preliminars d'implementació en ASIC. Això es va fer principalment amb la finalitat de tenir una estimació primerenca de la zona de dau per demostrar que el projecte en ASIC és econòmicament viable, així com per verificar possibles errors en l'etapa primerenca. Com en el cas del receptor ISDB-T, este receptor es basa molt en l'algorisme CORDIC i va ser un prototip de FPGA. La metodologia utilitzada per al segon receptor es deriva de la utilitzada per al receptor IRodrigues De Lima, E. (2016). Architecture and algorithms for the implementation of digital wireless receivers in FPGA and ASIC: ISDB-T and DVB-S2 cases [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61967TESI

Control of recombinant protein productivity and quality in mammalian cell culture

Various bioprocess parameters such as choice of host cell, or changes in the cell culture environment including: elevated ammonia or presence of serum, can influence the N-glycosylation of recombinant proteins with possible alterations in stability, antigenicity and clearance rate in vivo. The combination of capillary isoelectric focusing, HPLC and MALDI-mass spectrometry enabled elucidation of the composition and putative structure of the N-glycosylation of a model recombinant protein, TIMP-1. Additionally, a novel serial dual column assay was demonstrated for the rapid (< 45 mins) and routine quantification of TIMP-1 sialic acid isoforms. Cell line specific changes in the N-glycosylation of TIMP-1, produced by glutamine synthetase amplified Chinese hamster ovary (GS-CHO) and GS-NSO cell lines indicated that NSO TIMP-1 associated N-glycans exhibited reduced sialylation with significantly elevated levels of potentially immunogenic N-glycolyl neuraminic acid residues as opposed to the predominant n-acetyl neuraminic acid form. NSO, but not CHO, TEMP-1 N-glycans also had termini ending in immunogenic a1-3 linked galactose residues. A comparison of CHO recombinant protein production and N-glycosylation in 7 % serum-supplemented and serum-free media suggested that spinner-flask cultures in the latter had reduced overall cell growth (as measured by cumulative cell hours) but a higher overall cellular TIMP-1 productivity. Few changes were observed in sialylation due to variable serum content. Increases in the CHO intracellular sugar nucleotide pool of UDP-HexNAc (UDP-N- acetylglucosamine + UDP-N-acetylgalactosamine) through artificially elevated 1 Introduction ammonia concentrations coincided with reduced TIMP-1 N-glycan sialylation but predominantly unchanged antennarity. Culture supplementation with 20 mM N-acetyl-mannosamine (ManNAc), a precursor for sialic acid synthesis resulted in raised intracellular CMP-sialic acid levels and increased TIMP-1 sialylation. Elevated ammonia induced decreases in TIMP-1 sialylation were largely reversed with artificially increased intracellular CMP-NeuAc levels through ManNAc coaddition. High intracellular CMP-NeuAc overcoming UDP-GlcNAc mediated inhibition of CMP-NeuAc transport into the Golgi is a likely mechanism for this. A non-specific, pH determined reduction in sialylation is also likely

Late quaternary geochronologic, stratigraphic, and sedimentologic framework of the Trinity River incised valley: east Texas coast

Optically stimulated luminescence dates from the last glacial period falling–stage and lowstand Deweyville deposits along the Trinity River valley in Texas provided insight to their timing of deposition and allogenic controls on fluvial processes. Three distinguishable periods of incision and lateral channelbelt migration were the effect of both lowered sea levels and climate controlling factors within the drainage basin. Valley widening and deposition of the High, Middle, and Low Deweyville units were constructed and subsequently preserved as fluvial terraces during oxygen isotope stages (OIS) 3 through 2, from 65–32.5 ka, 32.5–23 ka, and 23–16 ka respectively. Although numerous workers using discharge retrodiction equations have inferred much greater discharges as the primary cause of the larger paleochannels of the glacial age Deweyville units, the reconstructed paleohydrology of the Trinity River using measurable parameters such as channel width, sediment caliber, and other geomorphic planform properties yields contrasting results to earlier studies. Sediment mass stored and exported during valley creation was assessed and calculated using a mass balance approach. Results clearly show that falling stage and lowstand fluvial deposits account for a large volumetric portion of the Trinity valley–fill sediments. Results also show that excavated sediment from the Coastal Plain represents only ca. 13% of the total hinterland derived sediment flux delivered by the Trinity system to downstream point sources over the last glacial period: periods of channel incision and valley deepening contribute little additional export of sediment, rather the process of lateral migration and channelbelt formation is contemporaneous with enhanced sediment flux to downslope systems. These results contrast long held concepts of incision and bypass during valley creation. An alternative hypothesis using a process based framework is presented as the primary cause of the larger Deweyville paleochannels. The resultant alluvial morphology of the Deweyville units was the result of floodplain longitudinal profile adjustment to sea–level change and the preexisting boundary conditions of the drainage basin and the emerging topography of the shelf, and an attempt of the fluvial system to attain the minimum channel slope required to transport upstream controls on water and sediment loads