Viral quantitative capillary electrophoresis for counting intact viruses

The quantification of a virus plays an important role in vaccine development, clinical diagnostics, and environmental contamination assays. In all these cases, it is essential to calculate the concentration or number of intact virus particles (ivp) and estimate the degree of degradation and contamination of virus samples. In this work, we propose a cost-efficient, robust method for the quantification and characterization of intact viruses based on capillary zone electrophoresis. This separation method is demonstrated on vaccinia virus (VV) with oncolytic properties. After virus sample preparation, the solution contains intact VV as well as broken viruses and residual DNA from the host cell used for preparation. Regulatory requirements limit the amount of the host cell DNA that can be present in vaccines or human therapeutics. We apply capillary electrophoresis to separate intact virus particles and the residual DNA and to measure the level of virus contamination with DNA impurities. Intercalating YOYO-1 dye is used to detect the encapsulated and free DNA by laser-induced fluorescence. After soft lysis of VV with proteinase K, all encapsulated DNA is dissolved to the free DNA. The change in peak areas and a DNA calibration curve help determine the initial concentration of intact viruses. This viral quantitative capillary electrophoresis (Viral qCE) is able to quantify the oncolytic vaccinia virus in the range of 10(6) to 10(12) ivp/mL.     

Differential patterns of antimicrobial resistance in population subsets of Escherichia coli isolated from waste- and surface waters

The species Escherichia coli comprises different subgroups with distinct phylogeny, physiology and ecology and, thus, presumably, with different roles in antimicrobial resistance dissemination. E. coli strains isolated from raw and treated municipal wastewater and from urban water streams were characterized in terms of phylogenetic groups, antimicrobial resistance patterns and the presence of class 1 and class 2 integrons. Our main objective was to investigate the contribution of the different phylo-groups in antimicrobial resistance dissemination in urban waters. Groups A and B1 were predominant in all types of water, evidencing, respectively, the lowest and the highest resistance prevalence. Municipal wastewater treatment was accompanied by significant increases of ciprofloxacin and streptomycin resistance (p < 0.01). Antimicrobial resistance prevalence differed significantly between the different phylo-groups and within the same group, mainly in group A. Such differences contributed to explain the higher ciprofloxacin and streptomycin resistance rates observed in treated effluent in comparison with the raw wastewater. We conclude that the dynamics of the bacterial populations has a major role on the dissemination of antimicrobial resistance in the environment.     

Overdrive in the ramp histogram test of ADCs

This paper presents a study about the amount of overdrive to use when analog-to-digital converters (ADCs) are tested with the ramp histogram method. Overdrive is used to limit the error induced by input-equivalent noise in the estimation of the ADC transition voltages. This study has direct application in the new coarse ramp static test.     

Incorporating Waiting Time in Competitive Location Models

In this paper we propose a metaheuristic to solve a new version of the Maximum Capture Problem. In the original MCP, market capture is obtained by lower traveling distances or lower traveling time, in this new version not only the traveling time but also the waiting time will affect the market share. This problem is hard to solve using standard optimization techniques. Metaheuristics are shown to offer accurate results within acceptable computing times.     

Compliance with hypertension treatment: 10 years of publications in Spain

INTRODUCTION: Ten years of publications (1984-1993) about drug compliance in spanish hypertensive patients are presented. MATERIAL AND METHODS: A bibliography search of Medline (EBSCO CD-ROM ver 104.1, act Jul 1995), Indice Médico Espa?ol (CSIC CD-ROM, act Oct 1993) and other sources has been made. RESULTS: 39 articles have been located and 23 investigational publications have been analysed. All the publications, but one, have evaluated the compliance by an indirect method, mainly patient selfdeclaration. The degree of patient compliance determined by interviews, questionnaires or inquiries is 55.5% (IC 95%: 52.7-58.3). The patient compliance in the publications that use methods based in pill counts is 46.4% (IC 95%: 41.6-51.2). The treatment dropout is present in the 18.5% of the patients (IC 95%: 20.5-16.5). CONCLUSIONS: The drug compliance degree in Spanish patients with hypertension is low.     

Multigrid methods for indefinite Toeplitz matrices

In this paper we modify a multigrid technique introduced for illconditioned symmetric positive definite Toepliltz linear systems [22] in order to deal with the nondefinite case. This kind of linear systems arises in important applications such as image restoration, harmonic retrieval etc. We prove that the cost per iteration isO(nlog² n) ops andO(log² n) parallel steps while the convergence speed seems to be independent of the problem matrix-size. Therefore this technique results to be competitive with respect to the fast direct method devised by Chan and Hansen [16] and is alternative to the PCG-based algorithm introduced in [33, 32, 37].     

DTC Drives for Wide Speed Range Applications Using a Robust Flux-Weakening Algorithm

A control scheme for robust flux-weakening operation of direct-torque-control induction motor drive is proposed. The basic idea is to adjust the flux reference on the basis of the torque error, thus determining a spontaneous flux weakening. To exploit the maximum torque capability, it is necessary to estimate the maximum torque that the induction machine is able to generate at any speed. Initially, a basic version of the algorithm, requiring a simple off-line parameter tuning, is presented. Then, the algorithm is improved and completed with the online estimation of the maximum torque, hence avoiding the initial tuning process. The main features of the proposed methods are a little dependence on machine parameters and a smooth transition into and out of the flux-weakening operation mode. Experimental tests demonstrate the effectiveness of the control schemes.     

Venous lesions in Beh?et''s disease

This study examined 117 patients with mild cervical atypia or atypical squamous cells of uncertain significance; it was found that 25% had histologically proven CIN lesions by colposcopically-directed punch biopsy or cone biopsy. 18% were found to have at least CIN 2 lesions and there was 1 case of invasive cancer. These data strongly support the recommendation of early colposcopic referral in patients with mild cervical atypia.     

Intercontinental spread of a multidrug-resistant methicillin-resistant Staphylococcus aureus clone

Two hundred ten methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered between 1990 and 1997 from three Portuguese hospitals located in Lisbon and Oporto were analyzed by molecular fingerprinting techniques. The hybridization of ClaI restriction digests with the mecA- and Tn554-specific DNA probes combined with pulsed-field gel electrophoresis documented the abrupt appearance and extensive intrahospital spread of the Brazilian epidemic MRSA clone in the 1995 samples of each one of the three hospitals analyzed-suggesting the intercontinental transfer of this strain from Brazil to Portugal. The appearance of this clone may challenge the dominance of another highly epidemic imported clone-the Iberian MRSA, currently the most widely spread MRSA clone in Portuguese hospitals.     

Optimization of mass effectiveness of axisymmetric pressure vessels

The optimization problems taken into consideration in this paper consist in finding the shape and the thickness distribution of elastic axisymmetric shells in the frame of membrane theory, loaded by fixed statical forces in such a way that the cost functional reaches a maximum, while satisfying some strength mechanics constraints. In this paper the mass effectiveness of the shell is considered as a cost function and as constraint we use the bounds on the maximum normal stress which is typical for shells made from brittle or quasi-brittle materials. The paper gives some possible formulations of optimal structural design problems. Analytical investigations and corresponding solutions are presented.