• Title/Summary/Keyword: University of Cambridge

Search Result 215, Processing Time 0.025 seconds

Generation of ovine recombinant prion protein (25-232): Characterisation via anti-PrP monoclonal antibodies and CD spectroscopy

  • Yang, Su-Jeong;Thackray, Alana;Bujdoso, Raymond
    • Korean Journal of Veterinary Service
    • /
    • v.28 no.4
    • /
    • pp.393-405
    • /
    • 2005
  • In prion pathogenesis, the structural conversion of the cellular prion protein $(PrP^c)$ to its abnormal isomer $(PrP^{Sc})$ is believed to be a major event. The susceptibility or resistance to natural sheep scrapie is associated with polymorphisms of host PrP gene (PRNP) at amino acid residues 136, to a lesser extent 154. The 112 residue in ovine PrP displays a natural polymorphism, Methionine to Threonine, which has not been thoroughly investigated. However the cell-free conversion assay showed that ARQ with Thr112 $(T_{112}ARQ)^{1)}$ presents lower convertibility to $PrP^{Sc}$than wild type ARQ $(M_{112}ARQ)$ [1] In this study we generated ovine recombinant PrPs of 112 allelic variants by metal chelate affinity chromatography and cation exchange chromatography. The final purity of the ovine PrP ARQ was more than $95\%$. These variants showed similar immunoreactivity against anti-PrP monoclonal antibodies in Western blot and ELISA. The refolded $M_{112}ARQ$ and $M_{112}ARQ$ presented the secondary structural content to similar extent via CD spectroscopy analysis. The inherited structural features of $M_{112}ARQ$ and $M_{112}ARQ$ under the different biophysical conditions are in the middle of investigation.

Ancient Human Parasites in Ethnic Chinese Populations

  • Yeh, Hui-Yuan;Mitchell, Piers D.
    • Parasites, Hosts and Diseases
    • /
    • v.54 no.5
    • /
    • pp.565-572
    • /
    • 2016
  • Whilst archaeological evidence for many aspects of life in ancient China is well studied, there has been much less interest in ancient infectious diseases, such as intestinal parasites in past Chinese populations. Here, we bring together evidence from mummies, ancient latrines, and pelvic soil from burials, dating from the Neolithic Period to the Qing Dynasty, in order to better understand the health of the past inhabitants of China and the diseases endemic in the region. Seven species of intestinal parasite have been identified, namely roundworm, whipworm, Chinese liver fluke, oriental schistosome, pinworm, Taenia sp. tapeworm, and the intestinal fluke Fasciolopsis buski. It was found that in the past, roundworm, whipworm, and Chinese liver fluke appear to have been much more common than the other species. While roundworm and whipworm remained common into the late 20th century, Chinese liver fluke seems to have undergone a marked decline in its prevalence over time. The iconic transport route known as the Silk Road has been shown to have acted as a vector for the transmission of ancient diseases, highlighted by the discovery of Chinese liver fluke in a 2,000 year-old relay station in northwest China, 1,500 km outside its endemic range.

Performance Issues with General Packet Radio Service

  • Chakravorty, Rajiv;Pratt, Ian
    • Journal of Communications and Networks
    • /
    • v.4 no.4
    • /
    • pp.266-281
    • /
    • 2002
  • The General Packet Radio Service (GPRS) is being deployed by GSM network operators world-wide, and promises to provide users with “always-on” data access at bandwidths comparable to that of conventional fixed-wire telephone modems. However, many users have found the reality to be rather different, experiencing very disappointing performance when, for example, browsing the web over GPRS. In this paper, we examine the causes, and show how unfortunate interactions between the GPRS link characteristics and TCP/IP protocols lead to poor performance. A performance characterization of the GPRS link-layer is presented, determined through extensive measurements taken over production networks. We present measurements of packet loss rates, bandwidth availability, link stability, and round-trip time. The effect these characteristics have on TCP behavior are examined, demonstrating how they can result in poor link utilization, excessive packet queueing, and slow recovery from packet losses. Further, we show that the HTTP protocol can compound these issues, leading to dire WWW performance. We go on to show how the use of a transparent proxy interposed near the wired-wireless border can be used to alleviate many of these performance issues without requiring changes to either client or server end systems.

Challenges and Some New Directions in Channel Coding

  • Arikan, Erdal;Hassan, Najeeb ul;Lentmaier, Michael;Montorsi, Guido;Sayir, Jossy
    • Journal of Communications and Networks
    • /
    • v.17 no.4
    • /
    • pp.328-338
    • /
    • 2015
  • Three areas of ongoing research in channel coding are surveyed, and recent developments are presented in each area: Spatially coupled low-density parity-check (LDPC) codes, nonbinary LDPC codes, and polar coding.

Outlier Robust Learning Algorithm for Gaussian Process Classification (가우시안 과정 분류를 위한 극단치에 강인한 학습 알고리즘)

  • Kim, Hyun-Chul;Ghahramani, Zoubin
    • Proceedings of the Korean Information Science Society Conference
    • /
    • 2007.10c
    • /
    • pp.485-489
    • /
    • 2007
  • Gaussian process classifiers (GPCs) are fully statistical kernel classification models which have a latent function with Gaussian process prior Recently, EP approximation method has been proposed to infer the posterior over the latent function. It can have a special hyperparameter which can treat outliers potentially. In this paper, we propose the outlier robust algorithm which alternates EP and the hyperparameter updating until convergence. We also show its usefulness with the simulation results.

  • PDF

Wireless operational modal analysis of a multi-span prestressed concrete bridge for structural identification

  • Whelan, Matthew J.;Gangone, Michael V.;Janoyan, Kerop D.;Hoult, Neil A.;Middleton, Campbell R.;Soga, Kenichi
    • Smart Structures and Systems
    • /
    • v.6 no.5_6
    • /
    • pp.579-593
    • /
    • 2010
  • Low-power radio frequency (RF) chip transceiver technology and the associated structural health monitoring platforms have matured recently to enable high-rate, lossless transmission of measurement data across large-scale sensor networks. The intrinsic value of these advanced capabilities is the allowance for high-quality, rapid operational modal analysis of in-service structures using distributed accelerometers to experimentally characterize the dynamic response. From the analysis afforded through these dynamic data sets, structural identification techniques can then be utilized to develop a well calibrated finite element (FE) model of the structure for baseline development, extended analytical structural evaluation, and load response assessment. This paper presents a case study in which operational modal analysis is performed on a three-span prestressed reinforced concrete bridge using a wireless sensor network. The low-power wireless platform deployed supported a high-rate, lossless transmission protocol enabling real-time remote acquisition of the vibration response as recorded by twenty-nine accelerometers at a 256 Sps sampling rate. Several instrumentation layouts were utilized to assess the global multi-span response using a stationary sensor array as well as the spatially refined response of a single span using roving sensors and reference-based techniques. Subsequent structural identification using FE modeling and iterative updating through comparison with the experimental analysis is then documented to demonstrate the inherent value in dynamic response measurement across structural systems using high-rate wireless sensor networks.

Design of RBFNNs Pattern Classifier Realized with the Aid of Face Features Detection (얼굴 특징 검출에 의한 RBFNNs 패턴분류기의 설계)

  • Park, Chan-Jun;Kim, Sun-Hwan;Oh, Sung-Kwun;Kim, Jin-Yul
    • Journal of the Korean Institute of Intelligent Systems
    • /
    • v.26 no.2
    • /
    • pp.120-126
    • /
    • 2016
  • In this study, we propose a method for effectively detecting and recognizing the face in image using RBFNNs pattern classifier and HCbCr-based skin color feature. Skin color detection is computationally rapid and is robust to pattern variation for face detection, however, the objects with similar colors can be mistakenly detected as face. Thus, in order to enhance the accuracy of the skin detection, we take into consideration the combination of the H and CbCr components jointly obtained from both HSI and YCbCr color space. Then, the exact location of the face is found from the candidate region of skin color by detecting the eyes through the Haar-like feature. Finally, the face recognition is performed by using the proposed FCM-based RBFNNs pattern classifier. We show the results as well as computer simulation experiments carried out by using the image database of Cambridge ICPR.