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  1. Article ; Online: Development of Composites of PLA Filled with Different Amounts of Rice Husk Fibers for Fused Deposition Modeling

    Pereira, Daniel F. / Branco, A.C. / Cláudio, Ricardo / Marques, Ana C. / Figueiredo-Pina, C. G.

    Journal of Natural Fibers. 2023 Apr. 24, v. 20, no. 1 p.2162183-

    2023  

    Abstract: Polylactic acid (PLA) has been used as a matrix material to produce composites with natural fibers, which present several advantages, being one of them the addition of value to agricultural waste. Thus, this study aims to develop a PLA 3D filament with ... ...

    Abstract Polylactic acid (PLA) has been used as a matrix material to produce composites with natural fibers, which present several advantages, being one of them the addition of value to agricultural waste. Thus, this study aims to develop a PLA 3D filament with the incorporation of a waste agriculture product (rice husk (RH)). For that, RH fibers were prepared, and PLA was loaded up to 20% RH. The filaments were obtained by extrusion. Finally, samples were produced by fused deposition modeling (FDM). The fibers and filaments’ density and thermal stability (TGA) were determined, and their chemical structure changes due to alkali treatment were accessed by Fourier Transform Infrared Spectroscopy (FTIR). Printability tests were performed, and printed samples were characterized in terms of density, water absorption, and mechanical behavior (compression, tensile, and flexural tests). The results showed that the alkali treatment changed the chemical structure of RH fibers and TGA showed that the filaments did not degrade significantly until 250ºC. The best printability was achieved with 5% of HR content and was the one that showed the lowest mechanical properties reduction. Overall, the present work showed that RH fibers can be successfully used as a filler in PLA filaments for FDM.
    Keywords Fourier transform infrared spectroscopy ; agricultural wastes ; alkali treatment ; chemical structure ; extrusion ; mechanical properties ; polylactic acid ; rice hulls ; thermal stability ; water uptake ; Rice husk ; natural fiber-filled polymer ; additive manufacturing ; PLA ; composites
    Language English
    Dates of publication 2023-0424
    Publishing place Taylor & Francis
    Document type Article ; Online
    ZDB-ID 2182715-1
    ISSN 1544-046X ; 1544-0478
    ISSN (online) 1544-046X
    ISSN 1544-0478
    DOI 10.1080/15440478.2022.2162183
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Understanding Social–Ecological Systems using Loop Analysis

    Scotti, Marco / da Silva Pereira, Daniel F. / Bodini, Antonio

    2020  

    Abstract: The sustainable management of social–ecological systems (SESs) requires that we understand the complex structure of relationships and feedbacks among ecosystem components and socioeconomic entities. Therefore, the construction and analysis of models ... ...

    Abstract The sustainable management of social–ecological systems (SESs) requires that we understand the complex structure of relationships and feedbacks among ecosystem components and socioeconomic entities. Therefore, the construction and analysis of models integrating ecological and human actors is crucial for describing the functioning of SESs, and qualitative modeling represents an ideal tool since it allows studying dependencies among variables of diverse types. In particular, the qualitative technique of loop analysis yields predictions about how a system’s variables respond to stress factors. Different interaction types, scarce information about functional relationships among variables, and uncertainties in the values of the parameters are the rule rather than exceptions when studying SESs. Accordingly, loop analysis seems to be perfectly suitable to investigate them. Here, we introduce the key aspects of loop analysis, discuss its applications to SESs, and suggest it enables making the first steps toward the integration of the three dimensions of sustainability.
    Language English
    Publisher Society for Human Ecology
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Phytochemical Screening and Acute Toxicity of Aqueous Extract of Leaves of Conocarpus erectus Linnaeus in Swiss Albino Mice.

    Nascimento, Dayane K D / Souza, Ivone A DE / Oliveira, Antônio F M DE / Barbosa, Mariana O / Santana, Marllon A N / Pereira, Daniel F / Lira, Eduardo C / Vieira, Jeymesson R C

    Anais da Academia Brasileira de Ciencias

    2016  Volume 88, Issue 3, Page(s) 1431–1437

    Abstract: Mangroves represent areas of high biological productivity and it is a region rich in bioactive substances used in medicine production. Conocarpus erectus (Combretaceae) known as button mangrove is one of the species found in mangroves and it is used in ... ...

    Abstract Mangroves represent areas of high biological productivity and it is a region rich in bioactive substances used in medicine production. Conocarpus erectus (Combretaceae) known as button mangrove is one of the species found in mangroves and it is used in folk medicine in the treatment of anemia, catarrh, conjunctivitis, diabetes, diarrhea, fever, gonorrhea, headache, hemorrhage, orchitis, rash, bumps and syphilis. The present study aimed to investigate the acute toxicity of aqueous extract of leaves of C. erectus in Swiss albino mice. The plant material was collected in Vila Velha mangroves, located in Itamaracá (PE). The material was subjected to a phytochemical screening where extractive protocols to identify majority molecules present in leaves were used. The evaluation of acute toxicity of aqueous extract of C. erectus followed the model of Acute Toxicity Class based on OECD 423 Guideline, 2001. The majority molecules were identified: flavonoids, tannins and saponins. The LD50 was estimated at 2,000 mg/kg bw. Therefore, the aqueous extract showed low acute toxicity classified in category 5.
    Language English
    Publishing date 2016-09
    Publishing country Brazil
    Document type Journal Article
    ZDB-ID 2046885-4
    ISSN 1678-2690 ; 0001-3765
    ISSN (online) 1678-2690
    ISSN 0001-3765
    DOI 10.1590/0001-3765201620150391
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Influence of TNF-α blockers on the oral prevalence of opportunistic microorganisms in ankylosing spondylitis patients.

    Pereira, Daniel F A / Pinheiro, Marcelo M / Silva, Pollyanna F N / Teodoro, Guilherme R / Brighenti, Fernanda L / Koga-Ito, Cristiane Y

    Clinical and experimental rheumatology

    2012  Volume 30, Issue 5, Page(s) 679–685

    Abstract: Objectives: To compare the oral prevalence and antimicrobial susceptibility of candida spp., staphylococci, enterobacteriaceae, and pseudomonas spp. from ankylosing spondylitis (AS) patients receiving conventional and anti-TNF-α therapy.: Methods: ... ...

    Abstract Objectives: To compare the oral prevalence and antimicrobial susceptibility of candida spp., staphylococci, enterobacteriaceae, and pseudomonas spp. from ankylosing spondylitis (AS) patients receiving conventional and anti-TNF-α therapy.
    Methods: The study included 70 AS patients, diagnosed according to the modified New York criteria (1984). The volunteers were divided into 2 groups: a biological group (AS BioG) (n=35) (on anti-TNF-α therapy) and a conventional group (AS ConvG) (n=35). The control group (ContG) (n=70) was made up of healthy individuals matched for age, gender, and oral conditions. After clinical examination, oral rinse samples were collected and plated in specific culture media. The number of colony-forming units per milliliter (cfu/ml) was obtained, and isolates were identified using the API system. Antimicrobial susceptibility tests were performed according to the NCCLS guidelines. Prevalence and counts of microorganisms were statistically compared between the 3 groups, using the Mann-Whitney and Chi-square tests. Significance level was set at 5%.
    Results: In both the AS BioG and the AS ConvG, staphylococci counts were higher than that in the ContG (p<0.0001). Candida albicans and staphylococcus epidermidis were the most commonly found species in all the groups. Serratia marcescens and klebsiella oxytoca were more prevalent in the AS BioG and the AS ConvG, respectively. Two candida isolates (2.8%) from the AS BioG and 5 (10.8%) from the AS ConvG were resistant to amphotericin B and 5-fluorocytosine. A low percentage of staphylococci isolates was resistant to amoxicillin, ciprofloxacin, and doxycycline.
    Conclusions: Higher counts of staphylococci were observed in both AS groups, regardless of the current therapy, age, sex, and oral conditions. Anti-TNF-α therapy could not be correlated with increased counts of microorganisms.
    MeSH term(s) Adult ; Anti-Infective Agents/therapeutic use ; Bacterial Infections/diagnosis ; Bacterial Infections/drug therapy ; Bacterial Infections/epidemiology ; Bacterial Infections/microbiology ; Brazil/epidemiology ; Chi-Square Distribution ; Colony Count, Microbial ; Cross-Sectional Studies ; Female ; Humans ; Immunologic Factors/adverse effects ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Mouth/microbiology ; Mouth Diseases/diagnosis ; Mouth Diseases/drug therapy ; Mouth Diseases/epidemiology ; Mouth Diseases/microbiology ; Opportunistic Infections/diagnosis ; Opportunistic Infections/drug therapy ; Opportunistic Infections/epidemiology ; Opportunistic Infections/microbiology ; Predictive Value of Tests ; Prevalence ; Spondylitis, Ankylosing/drug therapy ; Spondylitis, Ankylosing/epidemiology ; Spondylitis, Ankylosing/immunology ; Tumor Necrosis Factor-alpha/antagonists & inhibitors ; Tumor Necrosis Factor-alpha/metabolism
    Chemical Substances Anti-Infective Agents ; Immunologic Factors ; Tumor Necrosis Factor-alpha
    Language English
    Publishing date 2012-09
    Publishing country Italy
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 605886-3
    ISSN 1593-098X ; 0392-856X
    ISSN (online) 1593-098X
    ISSN 0392-856X
    Database MEDical Literature Analysis and Retrieval System OnLINE

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