Atividade de formação interprofissional em urgência pré-hospitalar

To acting in emergencies it is important that health professionals develop specific and differentiated skills, which shows us the importance of training in emergency planning. So undergraduate courses in medicine and nursing should encourage the development of these skills and evaluate them through various instruments targeted to the different fields. The aim of this study was to implement an optional and interprofessional curricular component, focusing on interprofessional education in pre-hospital emergency for medical and nursing courses Federal University of Rio Grande do Norte (UFRN). This is an exploratory descriptive study, with 24 medical and nursing graduates of last year undergraduate of supervised training, who underwent theoretical and practical training in the care of pre-hospital emergency services. There were theoretical and practical lessons per week for one school semester, taught by doctors and nurses of the Emergency Medical Service (EMS), where the topics discussed were: basic and advanced life support, safe transport in clinical emergencies, trauma, gynecological, obstetric, pediatric and psychiatric diseases, and have been carried out practical activities in ambulances. The students were evaluated by pre-test, post-test and practical stations made through the Objective Structured Clinical Evaluation (OSCE), in the skills laboratory of the Health Sciences Center. During the activities the students were encouraged to critical and reflective thinking, highlighting the importance of integration between the various health care professionals. It was observed that 88% of the students had a score increase over the pre-test. In the evaluation process carried out by medical students and nursing UFRN have similar expectations regarding the essential skills acquired during the training activity. The results of this study will form the basis for the organization of interprofessional education activity in pre-hospital emergency medical students and nursing, as well as helped to organize practices stations, identifying basic clinical skills, and implementing student assessment tools UFRN.

Estudo sobre a relação entre a atividade geomagnética e cintilações de sinais de GPS em Natal-RN (Brasil)

To identify the relationship between GPS scintillation in Natal-RN (Brazil) and geomagnetic disturbances of any intensities and variations, this work made analysis of the ionospheric behavior and magnetic indexes (Dst , AE and Bz of the interplanetary magnetic field) concerning to different periods of the solar cycle between 2000 and 2014. Part of the data of this research originated at the UFRN observatory, from a GEC Plessey board connected to an ANP -C 114 antenna, modified by Cornell University’s Space group Plasma Physics in order to operate the ScintMon, a GPS monitoring program. This study, therefore, found several cases of inhibited scintillations after the main phase of magnetic storms, a fact that, along with others, corroborated with categorization of Aarons (1991) and models of disturbed dynamo (according to Bonelli, 2008) and over-shielding penetration, defended by Kelley et al. (1979) and Abdu (2011) [4]. In addition to these findings, different morphologies were noted in such disruptions in the GPS signal in accordance with previous magnetic activities. It also found a moderate relationship (R2 = 0.52) between the Dst rate (concerning to specific time) and the average of S4 through a polynomial function. This finding therefore, corroborating Ilma et al. (2012) [17], is an important evidence that the scintillation GPS are not directly controlled by magnetic induction of storms. Completing this work, this relation did show itself as a way of partial predicting of scintillations.

O registro de procedimentos metodológicos em projetos de intervenção arquitetônica no patrimônio edificado: o caso de Natal-RN

In the midst of growing preservationist awareness, regarding methods of architectural intervention of buildings with a recognized heritage value, there are numerous approaches on how the original heritage value can be protected. However, can these intervention projects be differentiated? Is it possible to identify how they differ (if in fact they do) from an architectural project not related to preservation? Although there are numerous theoretical studies regarding methods utilized in architectonical projects, there appear to be a lack of studies focused on an architectural intervention exclusively focused on areas or edifications that have a recognized heritage value, thereby requiring a reflection on which methodological procedures in an architectonical project serve the purpose of the preservation of the historical aspects. This discussion is of even greater importance because, at the national level, some recent discussions on this type of architectural design seem arbitrary and lack methodological rigor. Therefore, this research attempts to focus equally on the theoretical-methodological practices of preservation as well as the architectural project methods. In an attempt to address these aspects, the focus of this research centers on the case studies of the intervention projects of the maritime passenger terminal of Natal (Terminal Marítimo de Passageriros de Natal), the old government hall (Palacio do Governo - EDTAM) and the old central hotel (Hotel Central) which are situated in the area known as the historic downtown of the city of Natal, within the federal heritage protection polygon. The analyses of these is intended to identify what methodological procedures were recorded in the final product (in the graphical representation of the architectural design and other documents) delivered to IPHAN / RN, the body responsible for review and approval of these architectural projects, noting whether such procedures appear, in some way, in the final product, and if an understanding of the complexity of preservation is evident. The analyses of these projects corroborate the hypothesis that there are unique characteristics, which must be addressed in the intervention project for preservation when compared to new project design. The main characteristic to be addressed is related to the very nature of the project. It is inherent in the dialectical relationship between the need to preserve (the identified heritage values) and the need to modernize (making adaptations to contemporary life). This relationship, denominated in this dissertation as "radical restraint", must, or at least should, guide the actions in the project as well as the technical analyses of the preservationist organization. However, this radical restriction appears more evident in the guidelines put forth by legislators than in the decisions of designers. These legislators require the presentation of documents, aimed at identifying and contextualizing intervention (Ordinance No. 420 of December 22, 2010), that grant (or should grant) assistance in the decision making process. It was evident in the analyses of these documents that there existed a disconnect between the documents produced and the decisions made in the project. This fact can be seen in the total absence of dialogue about theoretical-methodological preservationist principles, which, in our view, is an essential element of the methodological procedures of the intervention project needed to guide the legislative and project design discussions.

Estudo da variabilidade da deriva vertical do plasma ionosférico sobre a região de Natal/RN, Fortaleza/CE e Cachoeira Paulista/SP para alguns casos de tempestades magnéticas de abril a setembro de 2000

In this work are presented the results of research on the variation of vertical plasma drift from the F layer that commonly occurs during the period close to the going down of the sun (between 21UT - 22UT), and consisting of an increase in the F layer in time of day and a drop at night on the cities of Natal / RN (The 33.7º, 5.6º S), Fortaleza / CE (38.45º O, 3.9º S) and Cachoeira Paulista / SP (45.0ºO, 22.7º S ). Thus, data was used (ionograms) virtual height t ( h' ) as a function of the frequency F for the layer of the ionosphere. These data were collected through ionossonda type CADI (Canadian Advanced Digital Ionosonde) to the cities of Natal and Fortaleza, and the Digisonde DPS to the town of Cachoeira Paulista. They considered only the data available 2000 maximum solar year. With the virtual height ( h' ) data reduced in the frequencies of 6MHz and 5MHz, the next step was to calculate. The results showed that the variability of the vertical drift rate F ionospheric layer periods of magnetic storms is related both to the penetration of the electric fields as the disturbance dynamo electric fields.

Mapeamento das projeções retinianas para o sistema óptico acessório, colículo superior e complexo pré-tectal do sagui (callithrix jacchus)

The accessory optical system, the pretectal complex, and superior colliculus are important control centers in a variety of eye movement, being extremely necessary for image formation, consequently to visual perception. The accessory optical system is constituted by the nuclei: dorsal terminal nucleus, lateral terminal nucleus, medial terminal nucleus and interstitial nucleus of the posterior superior fasciculus. From a functional point of view they contribute to the image stabilization, participating in the visuomotor activity where all system cells respond to slow eye movements and visual stimuli, which is important for the proper functioning of other visual systems. The pretectal complex comprises a group of nuclei situated in mesodiencephalic transition, they are: anterior pretectal nucleus, posterior pretectal nucleus, medial pretectal nucleus, olivary pretectal nucleus and the nucleus of the optic tract, all retinal projection recipients and functionally are related to the route of the pupillary light reflex and the optokinetic nystagmus. The superior colliculus is an important subcortical visual station formed by layers and has an important functional role in the control of eye movements and head in response to multisensory stimuli. Our aim was to make a mapping of retinal projections that focus on accessory optical system, the nuclei of pretectal complex and the superior colliculus, searching mainly for pretectal complex, better delineation of these structures through the anterograde tracing with the B subunit of cholera toxin (CTb) followed by immunohistochemistry and characterized (measured diameter) synaptic buttons present on the fibers / terminals of the nucleus complex pré-tectal. In our results accessory optical system, including a region which appears to be medial terminal nucleus and superior colliculus, were strongly marked by fibers / terminals immunoreactive CTb as well as pretectal complex in the nucleus: optic tract, olivary pretectal nucleus, anterior pretectal nucleus and posterior pretectal nucleus. According to the characterization of the buttons it was possible to make a better definition of these nucleus.

O Programa Nacional Biblioteca da Escola - PNBE: da gestão ao leitor na educação infantil de Natal-RN

This study aims to investigate the process of implementation of Programa Nacional Biblioteca da Escola, PNBE, and the reader's training on Childhood Education level in Natal. The promotion of literary reading is the opportunity of inclusion in a world that is connected to citizenship, to human rights and social justice, because the reading is the way which gives meaning to the life and, therefore, it is a right for everybody. The study is characterized as a qualitative research with evaluative approach. The methodological procedure that constitutes this corpus took place in three stages: the first one was about the analysis of laws and documents of national public policies for the reading promotion; questionnaires were applied by Managing Committee - Natal/RN to CMEIs and the available websites from MEC that provide distribution of the acquis; in the second stage, we adopted the semi-structured interview as a methodological procedure elaborated with open questions that focus on the program management and to the acquis of PNBE; and in the third step we visited the 21 centers of childhood education in Natal for interviewing and to do the exploratory observation in places of reading. The Informant actors in this research are: the advisors of SME - Natal and FNDE, managers and teachers in Municipal Childhood Education Centers who totalize 30 informants. This theoretical and methodological framework follows the studies of Amarilha (1993; 1994; 2002; 2006; 2010; 2012), Bardin (2001), Bogdan; Biklen (1994), Castro (2007; 2008; 2012), Demo (2000; 2006; 2008), Fischer (2006), Moreira; Caleffe (2008), Paiva (2008; 2012), Secchi (2010; 2012), Soares (2003; 2008) and Zilberman (2001; 2003; 2008). The analysis indicates that decentralization strategy which is adopted in public management model will transfer responsibilities and assumption of the PNBE, exempting the actors to planning actions ensuring the efficiency and efficacy implementation on reading policy to national and municipal levels. The qualified acquis that is distributed by MEC reaches every Childhood Education center and does not depend on teacher's desire or it action, only a few of them know about it and they do not have information about the PNBE, neither receive specific training in order to articulate it to the practice of reading with children from Childhood Education. The reading project implemented by private education system in Natal overlaps the PNBE, making it invisible. The reading places that are available for that schooling stage are summarized to the reading corners. In some CMEI, books remain stored in boxes or they are locked in the closet, out of use to the teachers and students. Thus, care for the acquisition, selecting acquis, and a preoccupation to the supply of the reading and books for this education level are lost into volumes of closed boxes, teachers are jettisoned to this process and children do not have any enchantment to the reading or books. In this context, this paper draws attention to how much we should still investigate in order to understanding the perspectives, stresses and challenges from public policies for the reading promotion in our country. We hope that the research will help to improve the management model of the PNBE, ensuring the reading democratization and therefore the reader's training in early Childhood Education.

O Programa Nacional Biblioteca da Escola - PNBE: da gestão ao leitor na educação infantil de Natal-RN

This study aims to investigate the process of implementation of Programa Nacional Biblioteca da Escola, PNBE, and the reader's training on Childhood Education level in Natal. The promotion of literary reading is the opportunity of inclusion in a world that is connected to citizenship, to human rights and social justice, because the reading is the way which gives meaning to the life and, therefore, it is a right for everybody. The study is characterized as a qualitative research with evaluative approach. The methodological procedure that constitutes this corpus took place in three stages: the first one was about the analysis of laws and documents of national public policies for the reading promotion; questionnaires were applied by Managing Committee - Natal/RN to CMEIs and the available websites from MEC that provide distribution of the acquis; in the second stage, we adopted the semi-structured interview as a methodological procedure elaborated with open questions that focus on the program management and to the acquis of PNBE; and in the third step we visited the 21 centers of childhood education in Natal for interviewing and to do the exploratory observation in places of reading. The Informant actors in this research are: the advisors of SME - Natal and FNDE, managers and teachers in Municipal Childhood Education Centers who totalize 30 informants. This theoretical and methodological framework follows the studies of Amarilha (1993; 1994; 2002; 2006; 2010; 2012), Bardin (2001), Bogdan; Biklen (1994), Castro (2007; 2008; 2012), Demo (2000; 2006; 2008), Fischer (2006), Moreira; Caleffe (2008), Paiva (2008; 2012), Secchi (2010; 2012), Soares (2003; 2008) and Zilberman (2001; 2003; 2008). The analysis indicates that decentralization strategy which is adopted in public management model will transfer responsibilities and assumption of the PNBE, exempting the actors to planning actions ensuring the efficiency and efficacy implementation on reading policy to national and municipal levels. The qualified acquis that is distributed by MEC reaches every Childhood Education center and does not depend on teacher's desire or it action, only a few of them know about it and they do not have information about the PNBE, neither receive specific training in order to articulate it to the practice of reading with children from Childhood Education. The reading project implemented by private education system in Natal overlaps the PNBE, making it invisible. The reading places that are available for that schooling stage are summarized to the reading corners. In some CMEI, books remain stored in boxes or they are locked in the closet, out of use to the teachers and students. Thus, care for the acquisition, selecting acquis, and a preoccupation to the supply of the reading and books for this education level are lost into volumes of closed boxes, teachers are jettisoned to this process and children do not have any enchantment to the reading or books. In this context, this paper draws attention to how much we should still investigate in order to understanding the perspectives, stresses and challenges from public policies for the reading promotion in our country. We hope that the research will help to improve the management model of the PNBE, ensuring the reading democratization and therefore the reader's training in early Childhood Education.

Avaliação do cuidado de enfermagem na perspectiva da segurança do paciente em unidades de terapia intensiva: na visão de profissionais, pacientes e familiares

Technological advances combined with healthcare assistance bring increased risks related to patient safety, causing health institutions to be environments susceptible to losses in the provided care. Sectors of high complexity, such as Intensive Care Units have such characteristics highlighted due to being spaces designed for the care of patients in serious medical condition, when the use of advanced technological devices becomes a necessity. Thus, the aim of this study was to assess nursing care from the perspective of patient safety in intensive care units. This is an evaluative research, which combines various forms of data collection and analysis in order to conduct a deepened investigation. Data collection occurred in loco, from April to July 2014 in hospitals equipped with adult intensive care unit services. For this, a checklist instrument and semi-structured interviews conducted with patients, families, professionals were used in order to evaluate the structure-process-outcome triad. The instrument for nursing care assessment regarding Patient Safety included 97 questions related to structure and processes. Interviews provided data for outcome analysis. The selection of interviewees/participants was based on the willingness of potential participants. The following methods were used to collect data resulting from the instrument: statistical analysis of inter-rater reliability measure known as kappa (K); observations from judges resulting from the observation process; and added information obtained from the literature on the thematic. Data analysis from the interviews was carried out with IRAMUTEQ software, which used Descending Hierarchical Classification and Similarity analysis to aid in data interpretation. Research steps followed the ethical principles presented by Resolution No. 466 of December 12, 2012, and the results were presented in three manuscripts: 1) Evaluation of patient safety in Intensive Care Units: a focus on structure; 2) Health evaluation processes: a nursing care perspective on patient safety; 3) Patient safety in intensive care units: perception of nurses, family members and patients. The first article, related to the structure, refers to the use of 24 items of the employed instrument, showing that most of the findings were not aligned with the adequacy standards, which indicates poor conditions in structures offered in health services. The second article provides an analysis of the pillar of Processes, with the use of 73 items of the instrument, showing that 50 items did not meet the required standards for safe handling due to the absence of adequate scientific guidance and effective communication in nursing care process. For the third article, results indicate that intensive care units were safe places, yet urges for changes, especially in the physical structure and availability of materials and communication among professionals, patients and families. Therefore, our findings suggest that the nursing care being provided in the evaluated intensive care units contains troubling shortcomings with regards to patient safety, thereby evidencing an insecure setting for the assistance offered, in addition to a need for urgent measures to remedy the identified inadequacies with appropriate structures and implement protocols and care guidelines in order to consolidate an environment more favorable to patient safety.

Cuidado psicossocial em saúde mental: estudo em assentamentos rurais do Rio Grande do Norte

Dwellers of agrarian reform settlements have a life conditioned by poor living and work conditions, difficulties accessing health programs, social assistance and other public policies and by this exacerbating their psychosocial and environmental vulnerability, which has an impact on their mental health. This research investigates the availability of support by the health and social assistance staff, regarding the demands of common mental disorders and alcohol abuse of dwellers of nine settlements in Rio Grande do Norte. Fifty three experts from different professional categories were interviewed individually or in groups. The results indicate that the workers suffer from poor working conditions, attributes of patrimonial heritage and welfare, which still survives in Brazilian social policies and particularly at local administrations of the countryside. The staffs have little knowledge of the local conditions and of the mental health needs, which has a negative impact on the reception and offered care. The implemented health care still corresponds to the biomedical logic, characterized by ethnocentrism, technicality, biology, cure, individualism and specialization, with little participation of the dwellers and disregarding the traditional knowledge and practices of local health care and by this not achieving the expected results. The psychosocial attendance is not well coordinated, presenting problems with the follow-up and continuity of care. The psychosocial mental health care in rural context has to face the challenge of the reorganization of the health care networks, the establishment of primary health care close to the people’s everyday life, building intersectional practices considering a health multidetermination and health education connected to these specific contexts. Due to the lack of knowledge of the specifics of the life conditions of the dwellers and the fragmentation of the psychosocial health care network, these staffs do not abide and are not ready to face the mental health needs in order to interfere with these health iniquities.

Cuidado psicossocial em saúde mental: estudo em assentamentos rurais do Rio Grande do Norte

Dwellers of agrarian reform settlements have a life conditioned by poor living and work conditions, difficulties accessing health programs, social assistance and other public policies and by this exacerbating their psychosocial and environmental vulnerability, which has an impact on their mental health. This research investigates the availability of support by the health and social assistance staff, regarding the demands of common mental disorders and alcohol abuse of dwellers of nine settlements in Rio Grande do Norte. Fifty three experts from different professional categories were interviewed individually or in groups. The results indicate that the workers suffer from poor working conditions, attributes of patrimonial heritage and welfare, which still survives in Brazilian social policies and particularly at local administrations of the countryside. The staffs have little knowledge of the local conditions and of the mental health needs, which has a negative impact on the reception and offered care. The implemented health care still corresponds to the biomedical logic, characterized by ethnocentrism, technicality, biology, cure, individualism and specialization, with little participation of the dwellers and disregarding the traditional knowledge and practices of local health care and by this not achieving the expected results. The psychosocial attendance is not well coordinated, presenting problems with the follow-up and continuity of care. The psychosocial mental health care in rural context has to face the challenge of the reorganization of the health care networks, the establishment of primary health care close to the people’s everyday life, building intersectional practices considering a health multidetermination and health education connected to these specific contexts. Due to the lack of knowledge of the specifics of the life conditions of the dwellers and the fragmentation of the psychosocial health care network, these staffs do not abide and are not ready to face the mental health needs in order to interfere with these health iniquities.

A produção oral de inglês como LE em uma escola pública de Natal: uma experiência com a abordagem baseada em tarefas

The aim of this action research of mixed-methods was investigating the role of the tasks proposed by the Task-Based Learning, TBL (WILLIS, 1996) in the process of development of speech production in English as a foreign language (EFL) at the public school. Twenty-three students from a grade of secondary school from a state school in Rio Grande do Norte were exposed systematically to the implementation of the learning tasks focused in the speech production in EFL during two months. The instruments used at the data collection – pre and post-questionnaire; field notes; focal group; and pre and post-tests - generated two kinds of data: a) qualitative (the perception of the students about their speech production and the teaching of this ability at the public school; and, the usage of strategies of communication for these learners facing TBL); and, b) quantitative (the development of pronunciation; of accuracy in the proficiency tests (test KET – Cambridge, adapted); and, of Global Oral Proficiency (POG) of these learners after the accomplishment of the learning tasks). The quantitative results of the study indicate that there was a statistically significant development of pronunciation and accuracy at the proficiency tests, after the tasks experience. The qualitative findings, in turn, represented by the learners‟ reports and from the research teacher, show that there has been greater focus on the use of communicative strategies during the learners‟ oral production throughout the intervention with the tasks.

Métodos de avaliação nutricional para a suplementação oral com zinco em crianças pré-púberes não deficientes em zinco

Background: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cellmediated immune dysfunction, and cognitive impairment. Objective: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal nonzinc- deficient children. Design: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n = 31) and an experimental group (10 mg Zn/day, n = 31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results: Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p < 0.0001). Conclusions: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Métodos de avaliação nutricional para a suplementação oral com zinco em crianças pré-púberes não deficientes em zinco

Background: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cellmediated immune dysfunction, and cognitive impairment. Objective: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal nonzinc- deficient children. Design: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n = 31) and an experimental group (10 mg Zn/day, n = 31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results: Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p < 0.0001). Conclusions: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Receptores de citocinas proinflamatórias na pré-eclâmpsia

Preeclampsia is a disease specific of human pregnancy that affects 3-8% of pregnant women, and it is one of the three leading causes of maternal mortality and morbidity. The disease is characterized by hypertension and proteinuria after the 20th week of gestation. The risk factors for this disease are not completely understood but appear to include dysregulation of the immune response arising from defects in placentation, environmental and genetic factors. This study aimed to determine whether the variation in the amount of proinflammatory cytokine receptors IL-1R2, IL-6R and TNF-αR1 would be involved in preeclampsia. They were recruited women with preeclampsia (n=24) and women who evolved during pregnancy without changes in blood pressure (n=12) were recruited. Clinical and laboratory data were collected. The cytokine receptors (IL-1R2, TNF-αR1 and IL-6R) were assessed in mononuclear cells isolated from peripheral blood using flow cytometry (Control = 8; PE = 24). C-reactive protein (CRP) was determined by CRP ultrasensitive method (Control = 7; PE = 18) was performed using sera pregnant women. Women with preeclampsia had higher weight at the beginning of the pregnancy (p=0.0171) and lower gestational age at delivery (0.0008). Classical monocytes were decreased in preeclampsia but not intermediate or non-classical monocytes. The frequency of IL-1R2 pro inflammatory cytokine receptors is decreased in women with PE only in the subpopulation of non-classical monocytes (p = 0.0011). TNF-αR1 receptor and IL-6R, had a decreased frequency in the three subpopulations of monocyte (classic, intermediate and non-classical) when compared to women with normal pregnancy. An increase in IL-1R2 receptor in TCD4+ lymphocytes, but a decrease in TNF-receptor and IL-6R in women with preeclampsia were found. No differences in the frequency of those receptors in CD3+/CD8+ in preeclampsia. There was no difference in C-reactive protein in preeclampsia. The reduction in the amount of IL-1R2, TNF- αR1 and IL-6R monocytes and lymphocytes can be involved in the regulation of inflammation observed in preeclampsia, contributing to disease.

Avaliação da influência de surfactantes químico e biológico na hidrólise enzimática de casca de coco verde após pré-tratamento ácido/alcalino e com peróxido de hidrogênio alcalino

In Brazil many types of bioproducts and agroindustrial waste are generated currently, such as cacashew apple bagasse and coconut husk, for example. The final disposal of these wastes causes serious environmental issues. In this sense, waste lignocellulosic content, as the shell of the coconut is a renewable and abundant raw material in which its use has an increased interest mainly for the 2nd generation ethanol production. The hydrolysis of cellulose to reducing sugars such as glucose and xylose is catalysed by a group of enzymes called cellulases. However, the main bottleneck in the enzymatic hydrolysis of cellulose is the significant deactivation of the enzyme that shows irreversible adsorption mechanism leading to reduction of the cellulose adsorption onto cellulose. Studies have shown that the use of surfactants can modify the surface property of the cellulose therefore minimizing the irreversible binding. The main objective of the present study was to evaluate the influence of chemical and biological surfactants during the hydrolysis of coconut husk which was subjected to two pre-treatment in order to improve the accessibility of the enzymes to the cellulose, removing this way, part of the lignin and hemicellulose present in the structure of the material. The pre-treatments applied to coconut bagasse were: Acid/Alkaline using 0.6M H2SO4 followed by 1M NaOH, and the one with Alkaline Hydrogen Peroxide at a concentration of 7.35% (v/v) and pH 11.5. Both the material no treatment and pretreated were characterized using analysis of diffraction X-ray (XRD), Scanning Electron Microscopy (SEM) and methods established by NREL. The influence of both surfactants, chemical and biological, was used at concentrations below the critical micelle concentration (CMC), and the concentrations equal to the CMC. The application of pre-treatment with coconut residue was efficient for the conversion to glucose, as well as for the production of total reducing sugars, it was possible to observe that the pretreatment fragmented the structure as well as disordered the fibers. Regarding XRD analysis, a significant increase in crystallinity index was observed for pretreated bagasse acid/alkali (51.1%) compared to the no treatment (31.7%), while that for that treated with PHA, the crystallinity index was slightly lower, around 29%. In terms of total reducing sugars it was not possible to observe a significant difference between the hydrolysis carried out without the use of surfactant compared to the addition of Triton and rhamnolipid. However, by observing the conversions achieved during the hydrolysis, it was noted that the best conversion was using the rhamnolipíd for the husk pretreated with acid/alkali, reaching a value of 33%, whereas using Triton the higher conversion was 23.8%. The coconut husk is a residue which can present a high potential to the 2nd generation ethanol production, being the rhamonolipid a very efficient biosurfactant for use as an adjuvant in the enzymatic process in order to act on the material structure reducing its recalcitrance and therefore improving the conditions of access for enzymes to the substrate increasing thus the conversion of cellulose to glucose.