Synthesis and fluorescence properties of side-chain carboxylated 5,9-diaminobenzo[a]phenoxazinium salts

The efficient synthesis of a series of novel side-chain carboxylated 5,9-diaminobenzo[a]phenoxazinium salts is described. The ring system was prepared by the reaction of 5-alkylamino-2-nitrosophenol hydrochlorides with the appropriate N-alkylated-naphthylamine. Evaluation of the visible and fluorescence properties of the cationic dyes was carried out in ethanol and water at physiological pH. In both solvents they showed intense visible absorption maxima in the range 500-638 nm (ethanol) and 625-650 (water), and fluoresced strongly, with fluorescence maxima from 612 to 669 nm (ethanol) and from 654 to 685 nm (water). A wide variation in fluorescence quantum yields is observed, ranging from 0.051 to 0.50 and 0.065 to 0.32 in ethanol and water, respectively.Fundação para a Ciência e a Tecnologia (FCT)

Cell size distribution in a random tessellation of space governed by the Kolmogorov-Johnson-Mehl-Avrami model: Grain size distribution in crystallization

The space subdivision in cells resulting from a process of random nucleation and growth is a subject of interest in many scientific fields. In this paper, we deduce the expected value and variance of these distributions while assuming that the space subdivision process is in accordance with the premises of the Kolmogorov-Johnson-Mehl-Avrami model. We have not imposed restrictions on the time dependency of nucleation and growth rates. We have also developed an approximate analytical cell size probability density function. Finally, we have applied our approach to the distributions resulting from solid phase crystallization under isochronal heating conditions

Social theory and the politics of big data and method

This article is an intervention in the debate on big data. It seeks to show, firstly, that behind the wager to make sociology more relevant to the digital there lies a coherent if essentially unstated vision and a whole stance which are more a symptom of the current world than a resolute endeavour to think that world through; hence the conclusion that the perspective prevailing in the debate lacks both the theoretical grip and the practical impulse to initiate a much needed renewal of social theory and sociology. Secondly, and more importantly, the article expounds an alternative view and shows by thus doing that other possibilities of engaging the digital can be pursued. The article is thus an invitation to widen the debate on big data and the digital and a call for a more combative social theory

Nel positively regulates the genesis of retinal ganglion cells by promoting their differentiation and survival during development

Peer reviewedPublisher PD

The analysis of European lacquer : optimization of thermochemolysis temperature of natural resins

In order to optimize chromatographic analysis of European lacquer, thermochemolysis temperature was evaluated for the analysis of natural resins. Five main ingredients of lacquer were studied: sandarac, mastic, colophony, Manila copal and Congo copal. For each, five temperature programs were tested: four fixed temperatures (350, 480, 550, 650 degrees C) and one ultrafast thermal desorption (UFD), in which the temperature rises from 350 to 660 degrees C in 1 min. In total, the integrated signals of 27 molecules, partially characterizing the five resins, were monitored to compare the different methods. A compromise between detection of compounds released at low temperatures and compounds formed at high temperatures was searched. 650 degrees C is too high for both groups, 350 degrees C is best for the first, and 550 degrees C for the second. Fixed temperatures of 480 degrees C or UFD proved to be a consensus in order to detect most marker molecules. UFD was slightly better for the molecules released at low temperatures, while 480 degrees C showed best compounds formed at high temperatures

Making regulatory mechanisms work : lessons from cases of Private Sector Participation

This paper is about the regulation of private sector participation (PSP) in public water utilities. Using case studies from Argentina, Chile and the United Kingdom, it identifies and discusses the regulatory mechanisms that have been introduced and the issues surrounding information access, price and service quality regulation. The paper also analyses what measures have been implemented in these three cases in order to achieve regulatory accountability, independence and an adequate level of financial and human resources. The method adopted was case survey including the analysis of official regulatory documents and other relevant material and validation by an expert panel. It investigates the conditions that are necessary for regulatory mechanisms to be implemented and operated effectively in each context, and draws out some general conclusions for areas of improvement

Structural and properties of Zn-Al2O3-SiC nano-composite coatings by direct electrolytic process

In this paper, Zn-SiC and Zn-Al2O3-SiC composite coating were fabricated by electrodeposition technique from sulfates bath. The resulting composite coating was carried out by adding Al2O3/SiC particulate to a zinc-containing bath. The properties of the composite coating were investigated by SEM equipped with EDS, XRD, and AFM. The electrochemical behavior of the coating alloy was evaluated in 3.65 % NaCl with linear polarization technique and mechanically examined by durascan microhardness tester. The morphology of the thermal treated coatings at 400 °C in 6 h was viewed with high optical microscope (OPM). The results show hardness, thermal stability, and anti-corrosion properties of Zn-Al2O3-SiC were improved significantly as against Zn- SiC coating matrixes. This was attributed to dispersive strengthening effect and grain induced effort of Al2O3/SiC particulate. The decrease in corrosion and thermal stability at 15 g/L of SiC concentration may be as a result of agglomeration and the superimposed particle in the plating bath

Provider Attitudes toward the Voluntary Medical Male Circumcision Scale-Up in Kenya, South Africa, Tanzania and Zimbabwe.

Countries participating in voluntary medical male circumcision (VMMC) scale-up have adopted most of six elements of surgical efficiency, depending on national policy. However, effective implementation of these elements largely depends on providers' attitudes and subsequent compliance. We explored the concordance between recommended practices and providers' perceptions toward the VMMC efficiency elements, in part to inform review of national policies. As part of Systematic Monitoring of the VMMC Scale-up (SYMMACS), we conducted a survey of VMMC providers in Kenya, South Africa, Tanzania, and Zimbabwe. SYMMACS assessed providers' attitudes and perceptions toward these elements in 2011 and 2012. A restricted analysis using 2012 data to calculate unadjusted odds ratios and 95% confidence intervals for the country effect on each attitudinal outcome was done using logistic regression. As only two countries allow more than one cadre to perform the surgical procedure, odds ratios looking at country effect were adjusted for cadre effect for these two countries. Qualitative data from open-ended responses were used to triangulate with quantitative analyses. This analysis showed concordance between each country's policies and provider attitudes toward the efficiency elements. One exception was task-shifting, which is not authorized in South Africa or Zimbabwe; providers across all countries approved this practice. The decision to adopt efficiency elements is often based on national policies. The concordance between the policies of each country and provider attitudes bodes well for compliance and effective implementation. However, study findings suggest that there may be need to consult providers when developing national policies.\u

Are you what you emoji? How skin tone emojis and profile pictures shape attention and social inference processing

Emojis can express emotions and some aspects of the sender’s identity; however, only limited research has explored how the choice of skin tone in emojis influences the perceptions of the users. We examined the interaction between emoji skin tones and profile pictures in instant messaging, using self-reported and eye tracking measures. White participants viewed 14 screenshots of conversations (9 target and 5 fillers) where the sender used an emoji in a Darker or Lighter skin tone, or the default Yellow; alongside profile pictures displaying a Black or White individual, or a landscape as a neutral condition. Results showed that Black senders using Darker emojis were seen as warmer and closer to the receiver, but less competent, suggesting a dimensional compensation effect. Conversely, Black senders using Lighter emojis appeared more competent, but less warm. In the Neutral condition, Lighter emojis improved warmth and relationship quality, but reduced competence inferences, unlike Yellow and Darker emojis, suggesting a black sheep effect (in-group strictness). Yellow emojis were assumed to be sent by White individuals. Eye-tracking measures revealed an implicit bias towards White senders using Darker emojis, although such an impact was not observed for Black senders using Lighter emojis. Overall, findings indicate that skin tone emojis and profile pictures influence sender perception and challenge the neutrality of Yellow emojis.info:eu-repo/semantics/publishedVersio