[Poster Presentation] DETERMINATION OF ALKENYL SUCCINIC ANHYDRIDE(ASA)IN PULP AND PAPER SAMPLES

K.Sundberg,B.Holmbom,R.Ekman,J.Axberg,J.Nyman 한국펄프·종이공학회 1999 한국펄프종이학회 기타 간행물 Vol.- No.-

A method for the determination of alkenyl succinic anhydride (ASA) in pulp, paper and water samples is presented. The method, based on gas chromatography (GC), enables the determination of ASA in its different forms, that is fiber-bound ASA and unbound ASA. The latter normally comprises metal soaps of alkenyl succinic acid.<br/> In order to distinguish between bound and unbound ASA, the unbound ASA must first be extracted from the sample. In this study, we have shown that unbound ASA can be efficiently extracted from paper either with acidic acetone or acetone in the presence of KH₂PO₄. Acetone alone is not the proper solvent, since unbound ASA in paper often occurs as Ca-soaps which are not very soluble in acetone. For GC analysis, derivatization of the extracted components is necessary.<br/> Regarding determination of bound ASA, acid methanolysis on one hand, and alkaline hydrolysis followed by methylation<br/> with diazomethane on the other, gave similar recoveries of bound ASA. The different derivatization methods evaluated here, namely silylation, methylation with diazomethane, and methylation during acid methanolysis, all resulted in similar amounts of detected ASA.<br/> Resin acids may severely interfere with the quantification of ASA due to overlapping in GC analysis. This is especially true for wood-containing or rosin-sized paper grades, where resin acids are abundant. For reliable quantification, GC-MS used in selected-ion-monitoring (SIM) mode is recommended.

[Oral Session 6] THE ORIGIN AND DISTRIBUTION OF ANIONIC GROUPSIN TMP

Anna Sundberg,Andrey Pranovich,Bjarne Holmbom 한국펄프·종이공학회 1999 한국펄프종이학회 기타 간행물 Vol.- No.-

The distribution of anionic groups in the fibres, the fines, the colloidal fraction and the dissolved fraction, respectively, of thermo mechanical pulp (TMP) suspensions was determined. The influence of extraction, alkaline treatment and peroxide bleaching of spruce TMP were also studied.<br/> Spruce TMP was extracted with hexane, treated with alkali, or bleached with peroxide. Suspensions made at pH 5.5 were fractionated into long fibres, large fines, small fines, a colloidal fraction and a dissolved fraction. The charge of the fractions was determined using polyelectrolyte titration. To determine the origin of the charges, the contents of fatty acids, resin acids and acidic units in hemicelluloses in the different fractions were determined by gas chromatography.<br/> Extraction of TMP with hexane prior to fractionation increased the measured charge of the fibres. The removal of the wood resin probably uncovered some carboxyl groups on the fibre surfaces, or improved the penetration of polybrene into the pores of the fibres. The charge of the fines and the colloidal fraction was lower when the wood resin had been removed.<br/> Alkaline treatment of the TMP increased the charge of the fibres and fines, mainly because of demethylation of pectins. Alkaline treatment increased the charge also of the dissolved fraction. because of the release of pectic acids into the water phase. Alkaline peroxide bleaching further increased the charge of fibres and the dissolved fraction, most likely because of lignin oxidation. The charge of the colloidal fraction, consisting mainly of wood resin, was only slightly affected by alkaline treatment and peroxide bleaching.<br/> The anionic groups in TMP suspensions were mainly free uronic acids in the hemicelluloses. The contribution from the fatty and resin acids was substantial only for the colloidal fraction.

Wireless OFDM systems with multiple transmit and receive antennas with bit-interleaved coded modulation

Lee, Inkyu,Sundberg, C.-E.W. IEEE 2006 IEEE wireless communications Vol.13 No.3

A modified medium access control algorithm for systems with iterative decoding

Lee, I.,Sundberg, C.-E.W.,Choi, S.,Lee, W. IEEE 2006 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.5 No.2

Efficient transmission methods for fading radio channels often require an iterative decoder. This is for example the case for systems using turbo codes. Receiver decoder iterations could potentially lead to a latency problem which impacts the performance of the medium access control protocol. In this paper, we present modifications based on the carrier sense multiple access with collision avoidance (CSMA/CA) medium access control (MAC) protocol to accommodate the increased latency in the iterative processing. One area of applications is wireless local area networks (WLANs) with high data rate. The simulation results performed in the IEEE 802.11a WLAN environment by replacing the 802:11a's convolutional coding with turbo coding demonstrate that the proposed algorithm provides a throughput gain over the conventional method.

지오신세틱스를 이용한 바이오 필터 셀시스템 건설

Ronald S. Johnson,여상식,Randy Sundberg 한국토목섬유학회 2009 한국토목섬유학회지 Vol.8 No.4

Space-time bit-interleaved coded modulation for OFDM systems

Lee, Inkyu,Chan, A.M.,Sundberg, C.-E.W. IEEE 2004 IEEE transactions on signal processing Vol.52 No.3

Space-time coding techniques significantly improve transmission efficiency in radio channels by using multiple transmit and/or receive antennas and coordination of the signaling over these antennas. Bit-interleaved coded modulation gives good diversity gains with higher order modulation schemes using well-known binary convolutional codes on a single transmit and receive antenna link. By using orthogonal frequency division multiplexing (OFDM), wideband transmission can be achieved over frequency-selective fading radio channels without adaptive equalizers. In this correspondence, we combine these three ideas into a family of flexible space-time coding methods. The pairwise error probability is analyzed based on the correlated fading assumption. Near-optimum iterative decoders are evaluated by means of simulations for slowly varying wireless channels. Theoretical evaluation of the achievable degree of diversity is also presented. Significant performance gains over the wireless local area network (LAN) 802.11a standard system are reported.

Diversity Analysis for Space-Time Bit-Interleaved Coded Modulation Systems

Byoungchul Moon,Carl-Erik W. Sundberg,Dong-Joon Shin,Inkyu Lee 한국통신학회 2006 한국통신학회 학술대회논문집 Vol.2006 No.11

CYP1A1, GSTM1, and GSTT1 polymorphisms, smoking, and lung cancer risk in a pooled analysis among Asian populations.

Lee, Kyoung-Mu,Kang, Daehee,Clapper, Margie L,Ingelman-Sundberg, Magnus,Ono-Kihara, Masko,Kiyohara, Chikako,Min, Shen,Lan, Qing,Le Marchand, Loic,Lin, Pinpin,Lung, Maria Li,Pinarbasi, Hatice,Pisani, P American Association for Cancer Research 2008 Cancer Epidemiology, Biomarkers & Prevention Vol.17 No.5

<P>To evaluate the roles of CYP1A1 polymorphisms [Ile 462Val and T 6235C (MspI)] and deletion of GSTM1 and GSTT1 in lung cancer development in Asian populations, a pooled analysis was conducted on 13 existing studies included in Genetic Susceptibility to Environmental Carcinogenesis database. This pooled analysis included 1,971 cases and 2,130 controls. Lung cancer risk was estimated as odds ratios (OR) and 95% confidence intervals (95% CI) using unconditional logistic regression model adjusting for age, sex, and pack-year. The CYP1A1 6235C variant was associated with squamous cell lung cancer (TC versus TT: OR, 1.42; 95% CI, 0.96-2.09; CC versus TT: OR, 1.97; 95% CI, 1.26-3.07; P trend = 0.003). In haplotype analysis, 462Val-6235T and Ile-C haplotypes were associated with lung cancer risk with reference to the Ile-T haplotype (OR, 3.41; 95% CI, 1.78-6.53 and OR, 1.39; 95% CI, 1.12-1.71, respectively). The GSTM1-null genotype increased squamous cell lung cancer risk (OR, 1.36; 95% CI, 1.05-1.77). When the interaction was evaluated with smoking, increasing trend of lung cancer risk as pack-year increased was stronger among those with the CYP1A1 6235 TC/CC genotype compared with those with TT genotype (P interaction = 0.001) and with the GSTM1-null genotype compared with the present type (Pinteraction = 0.08, when no genotype effect with no exposure was assumed). These results suggest that genetic polymorphisms in CYP1A1 and GSTM1 are associated with lung cancer risk in Asian populations. However, further investigation is warranted considering the relatively small sample size when subgroup analyses were done and the lack of environmental exposure data other than smoking.</P>

An Efficient UEP Transmission Scheme for MIMO-OFDM Systems

이흔철,이병시,이인규,Lee, Heun-Chul,Lee, Byeong-Si,Sundberg, Carl-Erik W.,Lee, In-Kyu The Korean Institute of Communications and Informa 2007 韓國通信學會論文誌 Vol.32 No.5c

소스 코딩을 통해 얻어지는 대다수의 멀티미디어 데이터 정보는 여러 등급의 다른 비트에러민감도를 가지고 있다. 그러므로 효율적인 시스템 구현을 위해서는 데이터 고유의 비트에러민감도에 따라 서로 다른 수준의 에러 방지를 제공해야 한다. 이 논문에서는 다중안테나 (multiple-in multiple-out : MIMO) 기반의 OFDM시스템에서 효과적인 멀티미디어 정보를 전송하기 위한 차등 에러 방지 기법(Unequal error protection : UEP)을 제안한다. 차등의 에러 방지를 제공하는 시공간 코딩 기법을 설명하고 그 성능을 평가한다. MIMO 기법과 BICM (Bit-interleaved coded modulations) 기술은 보통 RCPC (Rate compatible punctured convolutional codes) 기법과 연계되어 구동된다. 이때 다중안테나 채널 이퀄라이저와 채널코딩 사이에 터보디코딩 기법을 적용하여 최상의 성능을 얻을 수 있는데 기존의 시스템에서는 동일한 에러방지기법(Equal Error Protection : EEP)을 사용하고 있다. 이 논문에서는 이런 시스템 구조에서 보통 사용되는 동일 에러 방지 기법(EEP)와 비교하여 차등 에러방지 기법(UEP)를 사용함으로써 얻을 수 있는 이득을 사용되는 전송파워와 채널밴드 측면에서 설명한다. 특히 제안된 알고리즘을 둘 또는 세 개의 전송 안테나와 두 개의 수신안테나를 갖는 다중안테나 시스템에 적용하고 8PSK 신호를 이용하여 플랫 페이딩 채널에서 성능을 평가하였다. Most multimedia source coders exhibit unequal bit error sensitivity. Efficient transmission system design should therefore incorporate the use of matching unequal error protection (UEP). In this paper, we present and evaluate a flexible space-time coding system with unequal error protection. Multiple transmit and receive antennas and bit-interleaved coded modulation techniques are used combined with rate compatible punctured convolutional codes. A near optimum iterative receiver is employed with a multiple-in multiple-out inverse mapper and a MAP decoder as component decoders. We illustrate how the UEP system gain can be achieved either as a power or bandwidth gain compared to the equal error protection system (EEP) for the identical source and equal overall quality for both the UEP and EEP systems. An example with two/three transmit and two receive antennas using BPSK modulation is given for the block fading channel.

Pharmacological Rescue of Mitochondrial Deficits in iPSC-Derived Neural Cells from Patients with Familial Parkinson's Disease

Cooper, O.,Seo, H.,Andrabi, S.,Guardia-Laguarta, C.,Graziotto, J.,Sundberg, M.,McLean, J. R.,Carrillo-Reid, L.,Xie, Z.,Osborn, T.,Hargus, G.,Deleidi, M.,Lawson, T.,Bogetofte, H.,Perez-Torres, E.,Clark American Association for the Advancement of Scienc 2012 Science Translational Medicine Vol.4 No.141

<P>Parkinson's disease (PD) is a common neurodegenerative disorder caused by genetic and environmental factors that results in degeneration of the nigrostriatal dopaminergic pathway in the brain. We analyzed neural cells generated from induced pluripotent stem cells (iPSCs) derived from PD patients and presymptomatic individuals carrying mutations in the PINK1 (PTEN-induced putative kinase 1) and LRRK2 (leucine-rich repeat kinase 2) genes, and compared them to those of healthy control subjects. We measured several aspects of mitochondrial responses in the iPSC-derived neural cells including production of reactive oxygen species, mitochondrial respiration, proton leakage, and intraneuronal movement of mitochondria. Cellular vulnerability associated with mitochondrial dysfunction in iPSC-derived neural cells from familial PD patients and at-risk individuals could be rescued with coenzyme Q(10), rapamycin, or the LRRK2 kinase inhibitor GW5074. Analysis of mitochondrial responses in iPSC-derived neural cells from PD patients carrying different mutations provides insight into convergence of cellular disease mechanisms between different familial forms of PD and highlights the importance of oxidative stress and mitochondrial dysfunction in this neurodegenerative disease.</P>