223 research outputs found

    Biopolymers by Azotobacter Vinelandii

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    An example lignocellulosic waste reuse in two consecutive steps: sorption of contaminants and enzymatic hydrolysis

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    In this study, an example of the reuse and revalorization of lignocellulosic waste from carnauba palm (Copernicia prunifera) leaves, macauba palm (Acrocomia aculeata) endocarp (shell) and European stone pine (Pinus pinea) nut shell is presented for the first time. The physical-chemical adsorption of Rhodamine B (RhB) dye for the different materials is studied in detail, together with the thermodynamic feasibility and the spontaneous and endothermic nature of the biosorption process. Subsequently, the production of total reducing sugars (TRS) is compared by enzymatic hydrolysis (before and after the adsorption process of the RhB pollutant), confirming the viability of TRS production in all cases, with yields ranging from 65.9% for pine nut shell (after adsorption) to 74.9% for the carnauba endocarp and to 84.0% for carnauba leaves (before adsorption). Hence the use of lignocellulosic materials as adsorbents does not preclude their ulterior reuse for obtaining fermentable sugars by enzymatic hydrolysis

    Rhodamine B removal with activated carbons obtained from lignocellulosic waste.

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    By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials

    Efficient microwave-assisted acid hydrolysis of lignocellulosic materials into total reducing sugars in ionic liquids

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    Different types of lignocellulosic materials (carnauba leaves, macauba shell and pine nut shell) and native cellulose have been studied for the production of total reducing sugars (TRS) through microwave-assisted acid-catalyzed hydrolysis in ionic liquids (ILs). Four reaction media have been assessed: two deep eutectic solvents (DES), choline chloride-oxalic acid (ChCl/ox) and choline chloride-urea (ChCl/urea), and two conventional ionic liquids, tetraethylammonium chloride (TEAC) and tetraethylammonium bromide (TEAB). Five acids (H2SO4, HCl, HNO3, H3PO4andp-toluensulfonic acid) have been evaluated in varying concentrations (5-30%) and time intervals (0-60 min), at different temperatures (100-140°C). Significant TRS production yields (as high as 83.7% in ChCl/ox for carnauba leaves) have been attained for both DES in combination with HNO3 10%, at 120°C for 30 min, with the additional advantage of low furfural and HMF by-products generation

    Occurrence Of Osteomuscular Symptoms In Teachers Of A Higher Education Institution

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    The objective of this study was to investigate the occurrence of musculoskeletal symptoms in teachers of a Higher Education Institution (HEI) located in João Pessoa – PB. This is a descriptive research with a quantitative approach, held at the Faculties of Nursing and Medicine (FACENE/FAMENE), in the city of João Pessoa-PB. The instrument for data collection consisted of a form with objective questions and divided into two parts, the first with data characterizing the sample and the second with the Nordic Musculoskeletal Symptoms Questionnaire. The data were analyzed quantitatively in percentage numbers and distributed in graphs. The results indicated that 30 teachers accepted to participate in the study with female predominance (67%). The regions most affected in the last 12 months were: dorsal (60%), lumbar (53%), neck, shoulders, wrists and hands (47%). Of the teachers interviewed, 20% reported having had difficulties in routine activities due to discomfort in the cervical region and 27% reported having sought medical or physiotherapeutic care due to neck pain, while 20% due to pain in the shoulders, dorsal, wrist/hands and hip/thighs. As for the occurrence of symptoms in the last week, the regions with the highest frequency of pain were shoulders (40%), neck and dorsal (27%). The significant percentage in the regions cited certifies that they are the regions most burdened in the professors and, therefore, deserve special attention in possible projects of occupational preventive action. This research evidences the necessity of new approaches and deepening on the subject, including the formulation of intervention strategies in the process of sickness of teachers. Descriptors: Work-Related Musculoskeletal Disorders. University Teachers. Worker's Health

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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