2,067 research outputs found
In situ anticaries efficacy of dentifrices with different formulations – A pooled analysis of results from three randomized clinical trials
Objectives
Data generated from three similar in situ caries crossover studies presented the opportunity to conduct a pooled analysis to investigate how dentifrice formulations with different fluoride salts and combinations at concentrations of 1400–1450 ppm F, different abrasive systems and in some cases, carbomer (Carb), affect enamel caries lesion remineralization and fluoridation.
Methods
Subjects continuously wore modified partial dentures holding two gauze-covered partially-demineralized human enamel specimens for 14 days and brushed 2×/day with their assigned dentifrice: Study 1: sodium fluoride (NaF)/Carb/silica, NaF/silica, NaF + monofluorophosphate (MFP)/chalk; Study 2: NaF/Carb/silica, NaF + MFP/dical, amine fluoride (AmF)/silica; Study 3: NaF/Carb/silica, NaF + stannous fluoride (SnF2)/silica/hexametaphosphate (HMP). All studies included Placebo (0 ppm F) and/or dose-response controls (675 ppm F as NaF [675F-NaF]) ±Carb. Specimens were evaluated for percentage surface microhardness recovery (SMHR) and enamel fluoride uptake (EFU).
Results
All 1400–1450 ppm F dentifrices except NaF + SnF2/silica/HMP provided significantly greater lesion remineralization than Placebo (p < 0.0001): differences in SMHR ranged from 17.46% (NaF + MFP/dical) to 26.66% (AmF/silica). For EFU (back-transformed log EFU), all 1400–1450 ppm F dentifrices gave significant fluoride uptake compared to Placebo (p < 0.0001): increases in EFU ranged from 4.95 μg F/cm2 (NaF + SnF2/silica/HMP) to 16.32 μg F/cm2 (NaF/carb/silica). Dentifrices containing NaF or AmF as sole fluoride source provided the greatest remineralization and fluoridation; Carb addition did not alter fluoride efficacy; some excipients appeared to interfere with the cariostatic action of fluoride. Treatments were generally well-tolerated with ≤4 treatment-related adverse events per study.
Conclusion
Commercially available fluoride dentifrices varied greatly in their ability to remineralize and fluoridate early caries lesions.
Clinical significance
Fluoride dentifrices are the most impactful anticaries modality worldwide. While clinical caries trials have not consistently shown the superiority of one formulation over another, these findings using a sensitive in situ caries model indicated that dentifrices containing NaF or AmF as the sole fluoride source provided the greatest remineralization and fluoridation benefits
Differences in need for instruction: Dynamic testing in children with arithmetic difficulties
Dynamic testing in practice : shall I give you a hint?
This dissertation contains studies concerning dynamic testing and graduated prompt techniques of children in elementary (special) education. The focus of the studies concerned teacher' opinions and teaching practice in particular from the perspective of needs based assessmentLEI Universiteit LeidenDevelopmental pathways of social-emotional and cognitive functioning - ou
Padronização de uma bateria para a avaliação de fatores de risco psicossociais trabalhistas em trabalhadores colombianos
A battery of questionnaires to assess psychosocial risk factors at work was developed in 2010 in response to Resolution 2646 created by the Colombian Ministry of Social Protection. However, this battery presents some theoretical and practical limitations. A new battery of instruments has been designed and validated that includes instruments and risk indicators of the demand-control-social support and the effort-reward imbalance models. Other factors, not included in these models, but that Resolution 2646 suggests should be assessed, have also been added, and with this additional information, the new battery allows us to also calculate a “global indicator” of demand, control, and social support; family and social risk conditions, coping and personality; and health and wellbeing. The new battery was administered to a sample of 16,095 workers from different occupations and representative Colombian regions. An analysis of the various domains indicates that internal consistency of the various scales is high. The new battery has the following properties: it is simple to use in paper format or when administered by computer, it enables comparison between occupations, it offers unified scores for each variable, and provides information to assess the risk factors suggested by Resolution 2646. In addition, it will make it possible to compare the results obtained when analyzing Colombian workers with those obtained from studies of workers from other countries.Em 2010, desenvolveu-se uma bateria de instrumentos para avaliar fatores psicossociais trabalhistas de risco para a saĂşde, em resposta Ă Resolução 2 646 do MinistĂ©rio da Proteção Social da ColĂ´mbia. Contudo, esta conta com algumas limitações que, a partir da construção e da validação de uma nova bateria, neste estudo se pretendem superar. AlĂ©m disso, a nova bateria oferece recursos adicionais para a avaliação desses fatores: a presente bateria incorpora os instrumentos e os indicadores centrais dos modelos demanda-controle-apoio social e desiquilĂbrio esforço-recompensa e os fatores internos do trabalho nĂŁo considerados nesses modelos, mas que a Resolução considera necessários, mediram-se com testes preexistentes ou desenvolvidos pelos autores. Com os dados coletados, Ă© possĂvel calcular indicadores globais de demanda, controle e apoio social; alĂ©m de condições familiares e sociais de risco, enfrentamento, personalidade e indicadores de saĂşde e bem-estar. Para a validação, a bateria foi aplicada a uma amostra de 16 095 trabalhadores de diferentes cargos e municĂpios colombianos. As anál i ses de consistĂŞncia interna e validade permitem afirmar que a bateria Ă© simples de aplicar em papel ou digital, permitirá comparar cargos, obter pontuações unificadas por variável, oferecer um diagnĂłstico de um nĂşmero importante das variáveis sugeridas na Resolução bem como permitirá comparar os resultados dos trabalhadores colombianos com os de outros paĂses. Palavras-chave: fatores trabalhistas de risco psicossocial, Resolução 2 646 de 2008, modelo demanda-controle-apoio social, modelo desiquilĂbrio esforço-recompensa, estresse profissional, avaliação.En 2010 se desarrollĂł una baterĂa de instrumentos para evaluar factores psicosociales laborales de riesgo para la salud, en respuesta a la ResoluciĂłn 2646 de 2008 del Ministerio de la ProtecciĂłn Social de Colombia. Sin embargo, esta cuenta con algunas limitaciones que, a partir de la construcciĂłn y validaciĂłn de una nueva baterĂa, en el presente estudio se buscan superar. La nueva baterĂa ofrece recursos adicionales para la evaluaciĂłn de estos factores: incorpora los instrumentos e indicadores centrales de los modelos demanda-control-apoyo social y desequilibrio esfuerzo-recompensa, y los factores intralaborales no contemplados en dichos modelos, pero que la ResoluciĂłn considera necesarios, se midieron con pruebas preexistentes o desarrolladas por los autores. Con los datos recolectados es posible calcular indicadores globales de demanda, control y apoyo social; además de condiciones familiares y sociales de riesgo, afrontamiento, personalidad e indicadores de salud y bienestar. Para la validaciĂłn, la baterĂa se aplicĂł a una muestra de 16.095 trabajadores de diferentes ocupaciones y municipios colombianos. Los análisis de consistencia interna y validez permiten afirmar que la baterĂa es sencilla de aplicar en papel o por computador, permitirá comparar ocupaciones, obtener puntuaciones unificadas por variable, ofrecer un diagnĂłstico de un nĂşmero importante de las variables sugeridas en la ResoluciĂłn y comparar los resultados de los trabajadores colombianos con los de otros paĂses
Encoding points on hyperelliptic curves over finite fields in deterministic polynomial time
We present families of (hyper)elliptic curve which admit an efficient
deterministic encoding function
A ~ 12 kpc HI extension and other HI asymmetries in the isolated galaxy CIG 340 (IC 2487)
HI kinematic asymmetries are common in late-type galaxies irrespective of
environment, although the amplitudes are strikingly low in isolated galaxies.
As part of our studies of the HI morphology and kinematics in isolated
late-type galaxies we have chosen several very isolated galaxies from the AMIGA
sample for HI mapping. Here we present GMRT 21-cm HI line mapping of CIG 340
which was selected because its integrated HI spectrum has a very symmetric
profile, Aflux = 1.03. Optical images of the galaxy hinted at a warped disk in
contrast to the symmetric integrated HI spectrum profile. Our aim is to
determine the extent to which the optical asymmetry is reflected in the
resolved HI morphology and kinematics. GMRT observations reveal significant HI
morphological asymmetries in CIG 340 despite it's overall symmetric optical
form and highly symmetric HI spectrum. The most notable HI features are: 1) a
warp in the HI disk (with an optical counterpart), 2) the HI north/south flux
ratio = 1.32 is much larger than expected from the integrated HI spectrum
profile and 3) a ~ 45" (12 kpc) HI extension, containing ~ 6% of the detected
HI mass on the northern side of the disk. We conclude that in isolated galaxies
a highly symmetric HI spectrum can mask significant HI morphological
asymmetries. The northern HI extension appears to be the result of a recent
perturbation (10^8 yr), possibly by a satellite which is now disrupted or
projected within the disk. This study provides an important step in our ongoing
program to determine the predominant source of HI asymmetries in isolated
galaxies. For CIG 340 the isolation from major companions, symmetric HI
spectrum, optical morphology and interaction timescales have allowed us to
narrow the possible causes the HI asymmetries and identify tests to further
constrain the source of the asymmetries.Comment: 10 page
SMEs in Europe 2003
Entrepreneurship and SMEs have emerged as the engine of economic and social development throughout the
world. The role of entrepreneurship has changed dramatically and fundamentally, so that it is now seen as a
requisite ingredient generating employment, economic growth and international competitiveness in the global
economy. The purpose of this report is first to explain why the role of SMEs is crucial for international competitiveness
and a strong economic performance in Europe, and then to document the role that SMEs play in
Europe.
Entrepreneurship and SMEs are related but certainly not identical concepts. Entrepreneurs, for example, are the
main drivers of the firm creation process where young and small firms play a role. On the other hand, the entrepreneurial
energy of a country, region or industry is often described using phenomena such as firm creation and
turbulence (Carree and Thurik, 2003).
The impact that SMEs have on economic performance in Europe is explained in Chapter 2. A careful measurement
of the structure and role of SMEs is required to understand the different roles that SMEs play and how
these roles are evolving throughout Europe. In particular, a measurement of SME activity in Europe provides (in
Section 3.1) what the (static) role of SMEs is in Europe, how the role of SMEs varies across specific countries and
how it is benchmarked against the other major areas in the world. How the economic role of SMEs has been
changing over time is presented in Section 3.2.
The way in which the measurement of the structure and role of SMEs is set up hinges on two views: first it attempts
to illustrate the theory-based results surveyed in Chapter 2. Second, it is in line with the measurements
given in earlier versions of the SME Observatory reports 'SMEs in Europe'.
A report about SMEs in Europe would however not be complete if no attention is paid to the current economic
setting. The European economy is recovering from an economic downturn. Very little information is available
about the roles of SMEs in the business cycle and in particular how do SMEs respond to economic adversity. This
issue is dealt with in Chapter 4.
Finally a Synthesis is presented in Chapter 5
Utilization of trihalogenated propanes by Agrobacterium radiobacter AD1 through heterologous expression of the haloalkane dehalogenase from Rhodococcus sp strain m15-3
Utilization of trihalogenated propanes by Agrobacterium radiobacter AD1 through heterologous expression of the haloalkane dehalogenase from Rhodococcus sp strain m15-3
Trihalogenated propanes are toxic and recalcitrant organic compounds. Attempts to obtain pure bacterial cultures able to use these compounds as sole carbon and energy sources were unsuccessful. Both the haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 (DhlA) and that from Rhodococcus sp, strain m15-3 (DhaA) were found to dehalogenate trihalopropanes to 2,3-dihalogenated propanols, but the kinetic properties of the latter enzyme are much better, Broad-host-range dehalogenase expression plasmids, based on RSF1010 derivatives, were constructed with the haloalkane dehalogenase from Rhodococcus sp, strain m15-3 under the control of the heterologous promoters P-lac, P-dhlA, and P-trc. The resulting plasmids yielded functional expression in several gram-negative bacteria. A catabolic pathway for trihalopropanes was designed by introducing these broad-host-range dehalogenase expression plasmids into Agrobacterium radiobacter AD1, which has the ability to utilize dihalogenated propanols for growth. The recombinant strain AD1 (pTB3), expressing the haloalkane dehalogenase gene under the control of the dhlA promoter, was able to utilize both 1,2,3-tribromopropane and 1,2-dibromo-3-chloropropane as sole carbon sources. Moreover, increased expression of the haloalkane dehalogenase resulted in elevated resistance to trihalopropanes.</p
Utilization of trihalogenated propanes by Agrobacterium radiobacter AD1 through heterologous expression of the haloalkane dehalogenase from Rhodococcus sp strain m15-3
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