Development of a transformation and selection system for the glycolipid-producing yeast Candida bombicola

Sophorolipids are surface-active compounds synthesized by the non-pathogenic yeast Candida bombicola. Over recent decades much effort has been spent to optimize culture conditions in order to improve the yield and production process. As far as we know, however, hardly any attention has been given to the genetics of the producing yeast strain itself and there are no published results available on the genetic engineering of C. bombicola. Nevertheless, this can be a useful tool for the study of the sophorolipid synthesis pathway and open up perspectives for improved production. A first step is the development of a suitable transformation and selection method. This article describes the creation and selection of an uracil auxotrophic C. bombicola mutant, which can be transformed back to prototrophy with the species' own orotidine 5'-phosphate decarboxylase or URA3 gene. Successful transformation was confirmed by a PCR-based method discriminating between the wild-type and mutated URA3 gene.     

An outcrossed canine pedigree for linkage analysis of hip dysplasia

Twenty-four hip replacements were performed with use of a medial protrusio technique to stabilize the fit of a hemispherical metal shell in the acetabulum in nineteen patients who had dysplasia of the hip. All of the hips were followed for a minimum of five years (average, seven years; range, five to thirteen years). Six of the hips were type I, seven were type II, eight were type III, and three were type IV according to the criteria of Crowe et al. The acetabular cup was implanted with the medial aspect of its dome beyond the Kohler line (drawn from the ischium along the ilioischial line) in all hips. An autogenous graft sculpted from the femoral head was used to cover 15 to 30 percent of the superolateral portion of the cup in one type-I hip, four type-III hips, and one type-IV hip. The need for these six bone grafts could have been avoided by reaming two to three millimeters more medially or by allowing 20 percent of the superolateral portion of the cup to be uncovered. Sixty to 84 percent of each bone graft was resorbed, effectively leaving the superolateral portion of the cup uncovered. The amount of the surface of the cup that was beyond the Kohler line averaged 41 percent for the six type-I hips, 43 percent for the seven type-II hips, 41 percent for six of the type-III hips, and 44 percent for one of the type-IV hips. Crossing of the ilioischial and iliopubic lines was noted on the radiographs of two type-III and two type-IV hips. Radiographs of two type-I hips and one type-II hip showed 7 to 17 percent of the surface of the dome of the cup through the internal pelvic wall (beyond the iliopubic line). None of the twenty-four metal shells were revised. A reoperation was performed on two hips to exchange a worn polyethylene insert, and three femoral components that had been fixed without cement were revised because of mechanical loosening. Wear averaged 0.26 millimeter per year in the fourteen hips that had a titanium femoral head and 0.09 millimeter per year in the nine hips that had a cobalt-chromium femoral head. The remaining hip had a ceramic femoral head, and the wear rate was 0.09 millimeter per year. The medial protrusio technique is a predictable, reproducible method for obtaining fixation of a porous-coated, hemispherical acetabular component in a dysplastic acetabulum. The technique permits the use of a porous-coated (bone-ingrowth) component; avoids the use of support bone graft and thereby reduces the operative time; facilitates rehabilitation by permitting earlier weight-bearing of the hip; and permits the use of a modular bearing surface, which may allow future exchange of only this surface rather than revision of the entire acetabular component because of excessive wear.     

Silhouette-based multi-sensor smoke detection

Fire is one of the leading hazards affecting everyday life around the world. The sooner the fire is detected, the better the chances are for survival. Today’s fire alarm systems, such as video-based smoke detectors, however, still pose many problems. In order to accomplish more accurate video-based smoke detection and to reduce false alarms, this paper proposes a multi-sensor smoke detector which takes advantage of the different kinds of information represented by visual and thermal imaging sensors. The detector analyzes the silhouette coverage of moving objects in visual and long-wave infrared registered (~aligned) images. The registration is performed using a contour mapping algorithm which detects the rotation, scale and translation between moving objects in the multi-spectral images. The geometric parameters found at this stage are then further used to coarsely map the silhouette images and coverage between them is calculated. Since smoke is invisible in long-wave infrared its silhouette will, contrarily to ordinary moving objects, only be detected in visual images. As such, the coverage of thermal and visual silhouettes will start to decrease in case of smoke. Due to the dynamic character of the smoke, the visual silhouette will also show a high degree of disorder. By focusing on both silhouette behaviors, the system is able to accurately detect the smoke. Experiments on smoke and non-smoke multi-sensor sequences indicate that the automated smoke detection algorithm is able to coarsely map the multi-sensor images. Furthermore, using the low-cost silhouette analysis, a fast warning, with a low number of false alarms, can be given.     

Corpus-based vocabulary lists for language learners for nine languages

We present the KELLY project and its work on developing monolingual and bilingual word lists for language learning, using corpus methods, for nine languages and thirty-six language pairs. We describe the method and discuss the many challenges encountered. We have loaded the data into an online database to make it accessible for anyone to explore and we present our own first explorations of it. The focus of the paper is thus twofold, covering pedagogical and methodological aspects of the lists’ construction, and linguistic aspects of the by-product of the project, the KELLY database.     

Fabrication of Functionally Graded and Aligned Porosity in Thin Ceramic Substrates With the Novel Freeze–Tape-Casting Process

Functionally graded and continuously aligned pore structures have been fabricated by a modified tape-casting process for use as solid oxide fuel cell electrodes, catalysts, sensors, and filtration/separation devices. Pore gradients from <5 to 100 μm and aligned pore tubules have been directly fabricated in various ceramic materials with thin substrate sections approximately 500–1500 μm utilizing both low-toxicity aqueous-based slips and organic solvents. This process allows for the generation of pores without the use of thermally fugitive pore formers in a single processing step with no need for tape lamination. The incorporation of tape casting, unidirectional solidification, and the freeze-drying process results in uniformly acicular pores aligned with the direction of the moving carrier film. Processing and microstructure variability will be discussed as it pertains to the effects of solids loading, freezing temperatures, and solvent type. Applications for this ceramic processing technology will also be discussed.     

Structural optimization with crashworthiness constraints

An automated structural design methodology has been devised which simultaneously considers design criteria associated with both linear elastic and crashworthiness loading conditions. This method is developed within the context of a nonlinear mathematical programming based structural optimization capability using an efficient two-phased crashworthiness analysis technique. Specially constructed nonlinear approximations for the crashworthiness constraints are employed to further reduce the computational burden during the optimization process. This methodology is demonstrated on an automobile structural design problem. It is shown that more mass efficient designs can be obtained by simultaneously considering elastic and crashworthiness design criteria as compared to a sequential approach in which the structure is first designed for the elastic loads and then modified to satisfy the crashworthiness criteria.     

SALSA: QoS-aware load balancing for autonomous service brokering

The evolution towards “Software as a Service”, facilitated by various web service technologies, has led to applications composed of a number of service building blocks. These applications are dynamically composed by web service brokers, but rely critically on proper functioning of each of the composing subparts which is not entirely under control of the applications themselves. The problem at hand for the provider of the service is to guarantee non-functional requirements such as service access and performance to each customer. To this end, the service provider typically divides the load of incoming service requests across the available server infrastructure. In this paper we describe an adaptive load balancing strategy called SALSA (Simulated Annealing Load Spreading Algorithm), which is able to guarantee for different customer priorities, such as default and premium customers, that the services are handled in a given time and this without the need to adapt the servers executing the service logic themselves. It will be shown that by using SALSA, web service brokers are able to autonomously meet SLAs, without a priori over-dimensioning resources. This will be done by taking into account a real time view of the requests by measuring the Poisson arrival rates at that moment and selectively drop some requests from default customers. This way the web servers’ load is reduced in order to guarantee the service time for premium customers and provide best effort to default customers. We compared the results of SALSA with weighted round-robin (WRR), nowadays the most used load balancing strategy, and it was shown that the SALSA algorithm requires slightly more processing than WRR but is able to offer guarantees - contrary to WRR - by dynamically adapting its load balancing strategy.     

Unexpected analyte oxidation during desorption electrospray ionization-mass spectrometry

During the analysis of surface-spotted analytes using desorption electrospray ionization-mass spectrometry (DESI-MS), abundant ions are sometimes observed that appear to be the result of oxygen addition reactions. In this investigation, the effect of sample aging, the ambient lab environment, spray voltage, analyte surface concentration, and surface type on this oxidative modification of spotted analytes, exemplified by tamoxifen and reserpine, during analysis by DESI-MS was studied. Simple exposure of the samples to air and to ambient lighting increased the extent of oxidation. Increased spray voltage also led to increased analyte oxidation, possibly as a result of oxidative species formed electrochemically at the emitter electrode or in the gas phase by discharge processes. These oxidative species are carried by the spray and impinge on and react with the sampled analyte during desorption/ionization. The relative abundance of oxidized species was more significant for the analysis of deposited analyte having a relatively low surface concentration. Increasing the spray solvent flow rate and the addition of hydroquinone as a redox buffer to the spray solvent were found to decrease, but not entirely eliminate, analyte oxidation during analysis. The major parameters that both minimize and maximize analyte oxidation were identified, and DESI-MS operational recommendations to avoid these unwanted reactions are suggested.     

Geochemical modelling of arsenic and selenium leaching in alkaline water treatment sludge from the production of non-ferrous metals

Geochemical modelling of leaching of oxyanion forming elements such as arsenic (As) and selenium (Se) is frequently not successful. A consistent thermodynamic dataset of As and Se was therefore composed, not only including precipitation, but also adsorption and solid solution, and was applied to the pH-dependent leaching behaviour of As and Se in an alkaline residue with a pH 11.1 from the lime treatment of sulphuric acid wastewaters from the production of non-ferrous metals. The As and Se content ranged up to 6.7 wt% and 0.29 wt%, respectively and speciation analysis showed that 96.3% of As occured as arsenate whereas Se speciation comprised 79% selenate and 21.0% selenite. XRD and SEM/EDX analysis showed that arsenate occurred as rauenthalite (Ca(3)(AsO(4))(2).10H(2)O), associated with gypsum, the most important mineral. Arsenate and arsenite concentrations were only slightly below equilibrium with rauenthalite and calciumarsenite (CaHAsO(3)), respectively and consideration of adsorption and solid solution only marginally improved model predictions. Selenate (Se(VI)) and selenite (Se(IV)), on the other hand, were far from equilibrium with their corresponding calcium metalate. The application of solid solutions and adsorption of Se(VI) and Se(IV) oxyanions with gypsum, calcite and ettringite significantly improved model predictions but missing thermodynamic data and especially the lack of a comprehensive model for solid solution and surface exchange with calcite and ettringite still hampered efficient modelling.