955 resultados para VP latex


Relevância:

20.00% 20.00%

Publicador:

Resumo:

texdoc provides tools to create a LaTeX document from within Stata in a weaving fashion. This is especially useful if you want to produce a LaTeX document that contains Stata output, such as, e.g., a Stata Journal article or solutions to statistics homework assignments.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Responsive core-shell latex particles are used to prepare colloidosome microcapsules using thermal annealing and internal cross-linking of the shell, allowing production of the microcapsules at high concentrations. The core-shell particles are composed of a polystyrene core and a shell of poly[2-(dimethylamino)ethyl methacrylate]-b-poly[methyl methacrylate] (PDMA-b-PMMA) chains adsorbed onto the core surface, providing steric stabilisation. The PDMA component of adsorbed polymer shell confers the latex particle thermal and pH responsive characteristics, it also provides glass transitions at lower temperatures than that of the core and reactive amine groups. These features facilitate the formation of stable Pickering emulsion droplets and the immobilisation of the latex particle monolayer on these droplets to form colloidosome microcapsules. The immobilisation is achieved through thermal annealing or cross-linking of the shell at mild conditions feasible for large scale economic production. We demonstrate here that it is possible to anneal the particle monolayer on the emulsion drop surface at 75-86 ºC by using the lower glass transition temperature of the shell compared to that of the polystyrene cores (~108 ºC). The colloidosome microcapsules formed have a rigid membrane basically composed of a monolayer of particles. Chemical cross-linking has also been successfully achieved by confining a cross-linker within the disperse droplet. This approach leads to the formation of single-layered stimulus-responsive soft colloidosome membranes and provides the advantage of working at very high emulsion concentrations since inter-droplet cross-linking is thus avoided. The porosity and mechanical strength of microcapsules are also discussed here in terms of the observed structure of the latex particle monolayers forming the capsule membrane.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Доклад, поместен в сборника на Националната конференция "Образованието в информационното общество", Пловдив, май, 2009 г.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Доклад, поместен в сборника на Националната конференция "Образованието в информационното общество", Пловдив, май, 2010 г.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The analysis of white latex paint is a problem for forensic laboratories because of difficulty in differentiation between samples. Current methods provide limited information that is not suitable for discrimination. Elemental analysis of white latex paints has resulted in 99% discriminating power when using LA-ICP-MS; however, mass spectrometers can be prohibitively expensive and require a skilled operator. A quick, inexpensive, effective method is needed for the differentiation of white latex paints. In this study, LIBS is used to analyze 24 white latex paint samples. LIBS is fast, easy to operate, and has a low cost. Results show that 98.1% of variation can be accounted for via principle component analysis, while Tukey pairwise comparisons differentiated 95.6% with potassium as the elemental ratio, showing that the discrimination capabilities of LIBS are comparable to those of LA-ICP-MS. Due to the many advantages of LIBS, this instrument should be considered a necessity for forensic laboratories.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A 17 month record of vertical particle flux of dry weight, carbonate and organic carbon were 25.8, 9.4 and 2.4g/m**2/y, respectively. Parallel to trap deployments, pelagic system structure was recorded with high vertical and temporal resolution. Within a distinct seasonal cycle of vertical particle flux, zooplankton faecal pellets of various sizes, shapes and contents were collected by the traps in different proportions and quantities throughout the year (range: 0-4,500 10**3/m**2/d). The remains of different groups of organisms showed distinct seasonal variations in abundance. In early summer there was a small maximum in the diatom flux and this was followed by pulses of tinntinids, radiolarians, foraminiferans and pteropods between July and November. Food web interactions in the water column were important in controlling the quality and quantity of sinking materials. For example, changes in the population structure of dominant herbivores, the break-down of regenerating summer populations of microflagellates and protozooplankton and the collapse of a pteropod dominated community, each resulted in marked sedimentation pulses. These data from the Norwegian Sea indicate those mechanisms which either accelerate or counteract loss of material via sedimentation. These involve variations in the structure of the pelagic system and they operatè on long (e.g. annual plankton succession) and short (e.g. the end of new production, sporadic grazing of swarm feeders) time scales. Connecting investigation of the water column with a high resolution in time in parallel with drifting sediment trap deployments and shipboard experiments with the dominant zooplankters is a promising approach for giving a better understanding of both the origin and the fate of material sinking to the sea floor.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Natural rubber latex, an aqueous colloidal dispersion of polyisoprene is widely used in production of gloves, catherers, rubber bands etc. The natural rubber latex content present in products such as gloves causes allergic problems. Of the different types of allergies reported, latex is known to produce Type I and Type IV allergies. Type I is called immediate hypersensitivity and type IV is called delayed hypersensitivity. It has been reported that some of the proteins present in the latex are mainly responsible for the allergic reactions type I. Significant reduction in the allergic response (type I) of natural rubber latex can be achieved by the reduction in its protein content, however out of the total proteins present in the latex or latex film only a fraction is extractable. The major techniques employed to reduce protein content of latex include leaching, autoclaving, chlorination, use of proteolytic enzymes and use of non ionic surfactants. Sulphur vulcanization of dipped products is responsible for Type IV allergy. N-nitrosamine, a carcinogenic substance is produced as a result of sulphur vulcanization. Radiation vulcanization can be used as an alternative for sulphur vulcanization. The current research deals with techniques to reduce the allergy associated with latex products. To reduce the type I allergy, low protein latex is developed using polyethylene glycol, a non- ionic surfactant. The present study employs radiation vulcanization to eliminate type IV allergy. The effect of different cure systems and fillers on the properties of low protein latex is also investigated as a part of the study.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nos profissionais de saúde a alergia ao látex representa um importante problema de saúde ocupacional. Em contexto hospitalar, a principal fonte de exposição alergénica é a utilização de luvas látex empoadas e a inalação dos bioaerossóis que se formam pela manipulação das mesmas. Mediante consentimento informado, os participantes preencheram um inquérito de resposta fechada e realizaram os testes cutâneos (TC). Aqueles que apresentaram reacção foram encaminhados para a consulta de imunoalergologia e realizaram TC para alimentos, doseamentos séricos de imunoglobulinas (lgE total e específica). Foram incluídos no estudo 44 dos 48 participantes (a=0.1). A sensibilidade ao látex foi posta em evidência em 15 dos elementos da amostra, seis dos quais reagem ao extracto de látex utilizado nos TC. A alergia ao látex foi diagnosticada em duas pessoas. A aplicação de questionários na avaliação sensibilização ocupacional ao látex pode vir a constituir ferramenta válida de auscultação deste problema nas instituições prestadoras de cuidados de saúde. ABSTRACT: Latex allergy is a major occupational disease among health care workers. ln hospitals, the main source of allergen exposure is the powdered latex gloves latex and the inhalation of the aerosols formed by its direct manipulation. By means of informed assent, the participants filled an inquiry and carried out the SPT. Those with cutaneous reaction to the latex extract went to an immunoallergology appointment. SPT for fruit and pollen with cross reactivity to latex allergens where performed, and blood levels of total and specific lgE where determined. The study group included 44 of the 48 participants (a=0.1). Fifteen elements showed latex sensitization and six of them had cutaneous reaction to the latex extract used in the SPT. Latex allergy was found in two health care professionals. Questionnaires may provide a reliability tool to access the sensitization due to natural rubber products and the symptoms more commonly associated with it, in health care facilities.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A proper cast is essential for a successful rehabilitation with implant prostheses, in order to produce better structures and induce less strain on the implants. The aim of this study was to evaluate the precision of four different mold filling techniques and verify an accurate methodology to evaluate these techniques. A total of 40 casts were obtained from a metallic matrix simulating three unit implant-retained prostheses. The molds were filled using four different techniques in four groups (n = 10): Group 1 - Single-portion filling technique; Group 2 - Two-step filling technique; Group 3 - Latex cylinder technique; Group 4 - Joining the implant analogs previously to the mold filling. A titanium framework was obtained and used as a reference to evaluate the marginal misfit and tension forces in each cast. Vertical misfit was measured with an optical microscope with an increase of 120 times following the single-screw test protocol. Strain was quantified using strain gauges. Data were analyzed using one-way ANOVA (Tukey's test) (α =0.05). The correlation between strain and vertical misfit was evaluated by Pearson test. The misfit values did not present statistical difference (P = 0.979), while the strain results showed statistical difference between Groups 3 and 4 (P = 0.027). The splinting technique was considered to be as efficient as the conventional technique. The strain gauge methodology was accurate for strain measurements and cast distortion evaluation. There was no correlation between strain and marginal misfit.