Search results for "equipment and supplies"
showing 10 items of 483 documents
Biomimetic composites with enhanced toughening using silk-inspired triblock proteins and aligned nanocellulose reinforcements
2019
Silk-like proteins produced in bacteria are used as adhesives for cellulose nanofibrils to make a new biological material.
New insights into the regulatory mechanisms of ppGpp and DksA on Escherichia coli RNA polymerase-promoter complex
2015
The stringent response modulators, guanosine tetraphosphate (ppGpp) and protein DksA, bind RNA polymerase (RNAP) and regulate gene expression to adapt bacteria to different environmental conditions. Here, we use Atomic Force Microscopy and in vitro transcription assays to study the effects of these modulators on the conformation and stability of the open promoter complex (RPo) formed at the rrnA P1, rrnB P1, its discriminator (dis) variant and lambda pR promoters. In the absence of modulators, RPo formed at these promoters show different extents of DNA wrapping which correlate with the position of UP elements. Addition of the modulators affects both DNA wrapping and RPo stability in a promo…
A free plate model can predict guided modes propagating in tubular bone-mimicking phantoms
2014
The goal of this work was to show that a non-absorbing free plate model can predict with a reasonable accuracy guided modes measured in bone-mimicking phantoms that have circular cross-section. Experiments were carried out on uncoated and coated phantoms using a clinical axial transmission setup. Adjustment of the plate model to the experimental data yielded estimates for the waveguide characteristics (thickness, bulk wave velocities). Fair agreement was achieved over a frequency range of 0.4 to 1.6 MHz. A lower accuracy observed for the thinnest bone-mimicking phantoms was caused by limitations in the wave number measurements rather than by the model itself.
Envejecimiento del cemento óseo de polimetilmetacrilato
1988
Aging of materials is an important factor in the long term behaviour of polymethylmethacrylate (PMMA) bone cement. A new method for evaluating the aging of this material by diferential scanning calorimetry is presented as well as results of measures made on an animal model and using material removed from falled artbroplasties. PMMA aging is nearly inexistent in tbe first weeks and little after sorne years.
Development of a polarimetric based optical biosensor using a free standing porous membrane
2013
The first published paper entitled Birefringent porous silicon membranes for optical sensing presents the results of the investigation on free standing silicon membranes prepared from p-type (110) surface oriented silicon as a material for optical biosensing. The birefringence and sensitivity of this type of porous membrane is theoretically simulated using the Bruggeman model which is extended to incorporate the influence that silicon oxidation has on both birefringence and sensitivity. Using this extended theoretical model a good agreement is found between the measured sensitivity values and the theoretical ones. The final section of this chapter describes the development of a statistical …
Relative Frequencies and Significance of Faecal Coliforms as Indicators Related to Water Temperature
1983
Summary The faecal coliforms at different sites of a hypereutrophic lake near Valencia (Albufera) were identified and their relative amounts established along an annual cycle. Using lauryl tryptose broth at 35°C, followed by incubation at 44.4°C in 2% brilliant green bile, Escherichia coli and Klebsiella pneumoniae are practically the only coliforms present. A positive correlation was found between the water temperature and the relative amount of these two coliforms: K. pneumoniae predominates at high water temperatures, whereas E. coli shows preponderance during the cold period. The role of K. pneumoniae as the only faecal indicator under the circumstances described in the work is emphasiz…
The Combitube, Self-Inflating Bulb, and Colorimetric Carbon Dioxide Detector to Advance Airway Management in the First Echelon of the Battlefield
2006
Combat lifesavers and Army medics are regular combat soldiers who possess skills that enable them to provide lifesaving assistance to combat casualties. Although their training is not equal to that of paramedics, combat lifesavers and Army medics are trained to assess casualties for airway obstruction, as well as the presence or absence of spontaneous ventilation. They are also familiar with the same basic airway maneuvers that are required for blind insertion of the esophageal-tracheal double-lumen airway (ETDLA). Use of the ETDLA in combination with an esophageal detector device and a colorimetric carbon dioxide detector would require skill similar to that which they already possess in pe…
Sulphate-Reducing Laboratory-Scale High-Rate Anaerobic Reactors for Treatment of Metal- and Sulphate-Containing Mine Wastewater
2002
Upflow anaerobic sludge blanket (UASB) reactors were used in this study to evaluate the feasibility of the sulphate-reducing, anaerobic high-rate process to treat metal- and sulphate-containing mining wastewater (MWW). Four simultaneous reactors, inoculated with different inocula (mesophilic granular sludge from two UASB reactors, one treating sugar refinery wastewater and the other board mill wastewater) and operated with different loadings, were for 95 days fed with synthetic feed consisting of glucose and sulphate. In all reactors, 23-72% of sulphate and 12-93% of COD were removed. Subsequently, two reactors were fed with diluted MWW (zinc as the main metal) for 77 days with hydraulic re…
Characterisation of nonoriented electric alloys under nonconventional conditions
1996
The variations of magnetic and loss characteristics of nonoriented cobalt-iron and silicon-iron sheets have been investigated using an Epstein frame. Cobalt-iron alloys have been tested under sinusoidal magnetic flux density with respect to frequency and temperature. Both kinds of alloys have also been investigated with respect to frequency, time constant wavefront and temperature under trapezoidal flux density. The qualitative behaviour is identical under both flux density conditions for all these alloys. These investigations have made it possible to model the variations of iron losses with experimental parameters, except the temperature. These quantitative evolutions differ with alloy and…
In vitro optical performance of a new aberration-free intraocular lens
2014
To assess the optical performance of the new EnVista intraocular lens (IOL). Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL’s aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield o…