Carbon Dots as a Fluorescence pH Nanosensor by Application of an Active Surface Preservation Strategy

In the environmental, industrial, and biomedical fields, pH monitorization is of the upmost importance. However, the most used type of pH sensors, glass pH-electrodes, still present limitations in their application in low volume samples and in cellular pH sensing, due to their size and invasive nature. Fluorescence-based sensors present a solution to such issues, providing a non-invasive solution to pH sensing. Herein, we report the rational development of carbon dots (CDs) as a pH nanosensor via an active surface preservation (ASP) method. Carbon dots (CDs) are carbon-based fluorescent nanoparticles with valuable properties such as high aqueous solubility, low cost and good biocompatibility, with remarkable fluorescence performance, been increasingly used as fluorescent nanosensors. Namely, these nanomaterials present advantages over molecular probes in terms of (photo)stability and water solubility, among others. By employing ASP strategies, the CDs will be prepared by using precursors with known active functional features. The ASP method allows the nanoparticles to retain the structural features of precursors, thus retaining their properties, without the need for costly and time-consuming post-synthesis functionalization procedures. In this work, we intend to provide a proof-of-concept of this type of strategy by utilizing the known pH-sensitivity of fluorescein to provide a pH-based response to CDs. The resulting CDs presented reversible response by fluorescence enhancement in the range of pH from 4 to 12. The nanoparticles exhibited excellent photostability, in different pH solutions. The studied CDs were also unaffected by, either variation of ionic strength or the presence of interferent species, while being compatible with human cancer cells. Finally, CDs were able to determine the pH of real samples. Thus, a selective pH fluorescent CDs-based nanosensor was developed.</jats:p

Seasonal Patterns of Growth and Senescence in \u3ci\u3eCynodon\u3c/i\u3e spp. cv Tifton 85 Grazed Swards

Growth and senescence are very important determinants of grassland productivity and correspond to key features to be considered for grazing management purposes. The present study was carried out at ESALQ, Piracicaba, S.P., Brazil and evaluated growth and senescence as a function of sward surface height. Mathematical models generated revealed that a similar pattern of response occurred as described in the literature for temperate grass species. However, a seasonal variation in response curves for growth and senescence was also observed and could be related to climatic events. Highest herbage accumulation rates were observed within the range of 15 to 20 cm of sward surface height

Avaliação do sistema radicular de Lima Ácida Tahiti em dois sistemas de manejo.

Para que as plantas cítricas tenham longevidade é necessário que o sistema radicular possa se desenvolver sem limitações. Rezende et al. (2002) registram o desenvolvimento prejudicado do sistema radicular de citros nos solos coesos dos Tabuleiros Costeiros, com as plantas geralmente exibindo sistema radicular superficial e enovelamento da raiz principal. A utilização de práticas de manejo de solo como, uso de coberturas vegetais e subsolagem, melhoram a morfologia da planta, uma melhor distribuição do sistema radicular permite explorar maior volume de solo para absorção de nutrientes e principalmente de água em profundidade. A produção citrícola nos Tabuleiros Costeiros, onde predominam Latossolos Amarelos e Argissolos Amarelos, caracterizados como profundos, ácidos e com presença de horizontes coesos (Jacomine et al., 1977), é realizada praticamente sem uso de irrigação, pois a região dispõe de uma distribuição de chuvas regular durante 9 a 10 meses/ano (CNPMF, 1993). Práticas culturais, como a utilização de leguminosas nas entrelinhas e herbicidas nas linhas, em áreas subsoladas a 0,50 m de profundidade, que foram capazes de aumentar o volume do sistema radicular dos citros neste ecossistema entre 68 e 148% e a produção de frutos entre 28 e 40%, respectivamente (Carvalho et al.,1999). O objetivo deste trabalho foi avaliar o sistema radicular da Lima Ácida Tahiti, verificando a capacidade das raízes de explorar o solo, comparando dois sistemas de cultivo.pdf 220

Barriers to cardiac rehabilitation delivery in a low-resource setting from the perspective of healthcare administrators, rehabilitation providers, and cardiac patients

Background: Despite clinical practice guideline recommendations that cardiovascular disease patients participate, cardiac rehabilitation (CR) programs are highly unavailable and underutilized. This is particularly true in low-resource settings, where the epidemic is at its’ worst. The reasons are complex, and include health system, program and patient-level barriers. This is the first study to assess barriers at all these levels concurrently, and to do so in a lowresource setting. Methods: In this cross-sectional study, data from three cohorts (healthcare administrators, CR coordinators and patients) were triangulated. Healthcare administrators from all institutions offering cardiac services, and providers from all CR programs in public and private institutions of Minas Gerais state, Brazil were invited to complete a questionnaire. Patients from a random subsample of 12 outpatient cardiac clinics and 11 CR programs in these institutions completed the CR Barriers Scale. Results: Thirty-two (35.2%) healthcare administrators, 16 (28.6%) CR providers and 805 cardiac patients (305 [37.9%] attending CR) consented to participate. Administrators recognized the importance of CR, but also the lack of resources to deliver it; CR providers noted referral is lacking. Patients who were not enrolled in CR reported significantly greater barriers related to comorbidities/functional status, perceived need, personal/family issues and access than enrollees, and enrollees reported travel/work conflicts as greater barriers than non-enrollees (all p < 0.01). Conclusions: The inter-relationship among barriers at each level is evident; without resources to offer more programs, there are no programs to which physicians can refer (and hence inform and encourage patients to attend), and patients will continue to have barriers related to distance, cost and transport. Advocacy for services is needed. Keywords: Health care services, Cardiac rehabilitation, Cardiac care facilities, Attitude of health personnelYork University Librarie

Estratégias de planejamento a partir do diagnóstico rápido participativo e da análise SWOT: um estudo na comunidade de São Bento, Salinopólis - PA.

A preocupação com o envolvimento das comunidades locais no desenvolvimento assumiu destaque nos estudos científicos, em especial, nas ciências sociais nas últimas décadas. Este artigo tem por objetivo propor estratégias que possam gerar ocupação e renda na comunidade de São Bento, no Município de Sanilópolis, no Estado do Pará, a partir das constatações da própria comunidade. O estudo aplicado, exploratório e descritivo, adotou abordagem qualitativa e utilizou técnicas de Diagnóstico Rápido Participativo (DRP), para coletar informações e análise SWOT para sistematizar os resultados do trabalho de campo. Participaram dos 19 grupos de trabalho, 53 entrevistados, caracterizando uma amostragem não probabilística por acessibilidade. Os resultados da pesquisa indicaram seis estratégias principais capazes de contribuir para a melhoria das condições de vida na região. Observa-se que engajar a comunidade no planejamento pode fundamentar ações de cidadania, contribuindo para uma realidade local mais justa, participativa e com visão de futuro

Caracterização de indicadores da qualidade do solo, com ênfase às áreas de várzea do Rio Grande do Sul.

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Avaliação da coleção de germoplasma de melancia da Embrapa Hortaliças para tolerância a virose.

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