Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 110
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Int J Mol Sci ; 25(10)2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38791210

RESUMO

Functional microexons have not previously been described in filamentous fungi. Here, we describe a novel mechanism of transcriptional regulation in Trichoderma requiring the inclusion of a microexon from the Xlr2 gene. In low-glucose environments, a long mRNA including the microexon encodes a protein with a GAL4-like DNA-binding domain (Xlr2-α), whereas in high-glucose environments, a short mRNA that is produced encodes a protein lacking this DNA-binding domain (Xlr2-ß). Interestingly, the protein isoforms differ in their impact on cellulase and xylanase activity. Deleting the Xlr2 gene reduced both xylanase and cellulase activity and growth on different carbon sources, such as carboxymethylcellulose, xylan, glucose, and arabinose. The overexpression of either Xlr2-α or Xlr2-ß in T. virens showed that the short isoform (Xlr2-ß) caused higher xylanase activity than the wild types or the long isoform (Xlr2-α). Conversely, cellulase activity did not increase when overexpressing Xlr2-ß but was increased with the overexpression of Xlr2-α. This is the first report of a novel transcriptional regulation mechanism of plant-cell-wall-degrading enzyme activity in T. virens. This involves the differential expression of a microexon from a gene encoding a transcriptional regulator.


Assuntos
Celulases , Proteínas Fúngicas , Regulação Fúngica da Expressão Gênica , Trichoderma , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Trichoderma/genética , Trichoderma/metabolismo , Trichoderma/enzimologia , Celulases/metabolismo , Celulases/genética , Endo-1,4-beta-Xilanases/metabolismo , Endo-1,4-beta-Xilanases/genética , Parede Celular/metabolismo , Açúcares/metabolismo
2.
J Phys Chem A ; 127(38): 7997-8014, 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37703453

RESUMO

Quantum chemical bonding descriptors based on the total and overlap density can provide valuable information about chemical interactions in different systems. However, these descriptors can be sensitive to the basis set used. To address this, different numerical treatments of electron density have been proposed to reduce the basis set dependency. In this work, we introduce overlap properties (OPs) obtained through numerical treatment of the electron density and present the topology of overlap density (TOP) for the first time. We compare the basis set dependency of numerical OP and TOP descriptors with their quantum theory of atoms in molecules (QTAIM) counterparts, considering the total electron density. Three single (C-C, C-O, and C-F) bonds in ethane, methanol, and fluoromethane and two double (C═C and C═O) bonds in ethene and formaldehyde were analyzed. Diatomic molecules Li-X with X = F, Cl, and Br were also analyzed. Eight parameters, including QTAIM descriptors and OP/TOP descriptors, are used to assess the basis dependency at the ωB97X-D level of theory using 28 basis sets from three classes: Pople, Ahlrichs, and Dunning. The study revealed that the topological overlap electron density properties exhibit comparatively lesser dependence on the basis set compared to their total electron density counterparts. Remarkably, these properties retain their chemical significance even with reduced basis set dependency. Similarly, numerical OP descriptors show less basis set dependency than their QTAIM counterparts. The excess of polarization functions increases charge concentration in the interatomic region and influences both QTAIM and OP descriptors. The basis sets Def2TZVP, 6-31++G(d,p), 6-311++G(d,p), cc-pVDZ, cc-pVTZ, and cc-pVQZ demonstrate reduced variability for the tested bond classes in this study, with particular emphasis on the triple-ζ quality Ahlrichs' basis set. We recommend against using basis sets with numerous polarization functions, such as augmented Dunning's and Ahlrichs' quadruple-ζ.

3.
Fish Shellfish Immunol ; 114: 301-310, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33984485

RESUMO

Our recent data show the valuable potential of TnP for the development of a new and safe anti-inflammatory drug due to its ability to control the traffic and activation of leukocytes in response to inflammation. Although there is considerable knowledge surrounding the cellular mechanisms of TnP, less is known about the mechanistic molecular role of TnP underlying its immunomodulatory functions. Here, we conducted investigations to identify whether miRNAs could be one of the molecular bases of the therapeutic effect of TnP. Using a zebrafish model of neutrophilic inflammation with a combination of genetic gain- and loss-of-function approaches, we showed that TnP treatment was followed by up-regulation of only four known miRNAs, and mature dre-miR-26a-1, herein referred just as miR-26a was the first most highly expressed. The knockdown of miR-26a ubiquitously resulted in a significant reduction of miR-26a in embryos, accompanied by impaired TnP immunomodulatory function observed by the loss of the control of the removal of neutrophils in response to inflammation, while the overexpression increased the inhibition of neutrophilic inflammation promoted by TnP. The striking importance of miR-26a was confirmed when rescue strategies were used (morpholino and mimic combination). Our results identified miR-26a as an essential molecular regulator of the therapeutic action of TnP, and suggest that miR-26a or its targets could be used as promising therapeutic candidates for enhancing the resolution of inflammation.


Assuntos
Anti-Inflamatórios/farmacologia , Transtornos Leucocíticos/veterinária , MicroRNAs/genética , Peptídeos/farmacologia , Animais , Anti-Inflamatórios/química , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Larva/efeitos dos fármacos , Larva/genética , Transtornos Leucocíticos/tratamento farmacológico , Conformação Proteica , Peixe-Zebra
4.
Lasers Med Sci ; 36(4): 735-742, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32583187

RESUMO

The repair of large bone defects is lengthy and complex. Both biomaterials and phototherapy have been used to improve bone repair. We aimed to describe histologically the repair of tibial fractures treated by wiring (W), irradiated or not, with laser (λ780 nm, 70 mW, CW, spot area of 0.5 cm2, 20.4 J/cm2 (4 × 5.1 J/cm2, Twin Flex Evolution®, MM Optics, Sao Carlos, SP, Brazil) per session, 300 s, 142.8 J/cm2 per treatment) or LED (λ850 ± 10 nm, 150 mW, spot area of 0.5 cm2, 20.4 J/cm2 per session, 64 s, 142.8 J/cm2 per treatment, Fisioled®, MM Optics, Sao Carlos, Sao Paulo, Brazil) and associated or not to the use of mineral trioxide aggregate (MTA, Angelus®, Londrina, PR, Brazil). Inflammation was discrete on groups W and W + LEDPT and absent on the others. Phototherapy protocols started immediately before suturing and repeated at every other day for 15 days. Collagen deposition intense on groups W + LEDPT, W + BIO-MTA + LaserPT and W + BIO-MTA + LEDPT and discrete or moderate on the other groups. Reabsorption was discrete on groups W and W + LEDPT and absent on the other groups. Neoformation varied greatly between groups. Most groups were partial and moderately filed with new-formed bone (W, W + LaserPT, W + LEDPT, W + BIO-MTA + LEDPT). On groups W + BIO-MTA and W + BIO-MTA + LaserPT bone, neoformation was intense and complete. Our results are indicative that the association of MTA and PBMT (λ = 780 nm) improves the repair of complete tibial fracture treated with wire osteosynthesis in a rodent model more efficiently than LED (λ = 850 ± 10 nm).


Assuntos
Compostos de Alumínio/farmacologia , Fios Ortopédicos , Compostos de Cálcio/farmacologia , Terapia com Luz de Baixa Intensidade , Óxidos/farmacologia , Silicatos/farmacologia , Fraturas da Tíbia/radioterapia , Fraturas da Tíbia/cirurgia , Compostos de Alumínio/uso terapêutico , Animais , Compostos de Cálcio/uso terapêutico , Combinação de Medicamentos , Óxidos/uso terapêutico , Roedores , Silicatos/uso terapêutico
5.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281181

RESUMO

Curcumin (CUR) is a natural substance extracted from turmeric that has antimicrobial properties. Due to its ability to absorb light in the blue spectrum, CUR is also used as a photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT). However, CUR is hydrophobic, unstable in solutions, and has low bioavailability, which hinders its clinical use. To circumvent these drawbacks, drug delivery systems (DDSs) have been used. In this review, we summarize the DDSs used to carry CUR and their antimicrobial effect against viruses, bacteria, and fungi, including drug-resistant strains and emergent pathogens such as SARS-CoV-2. The reviewed DDSs include colloidal (micelles, liposomes, nanoemulsions, cyclodextrins, chitosan, and other polymeric nanoparticles), metallic, and mesoporous particles, as well as graphene, quantum dots, and hybrid nanosystems such as films and hydrogels. Free (non-encapsulated) CUR and CUR loaded in DDSs have a broad-spectrum antimicrobial action when used alone or as a PS in aPDT. They also show low cytotoxicity, in vivo biocompatibility, and improved wound healing. Although there are several in vitro and some in vivo investigations describing the nanotechnological aspects and the potential antimicrobial application of CUR-loaded DDSs, clinical trials are not reported and further studies should translate this evidence to the clinical scenarios of infections.


Assuntos
Anti-Infecciosos/administração & dosagem , Curcumina/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/administração & dosagem , Curcumina/química , Humanos , Micelas , Nanomedicina/métodos , Nanopartículas/química
6.
Genet Mol Biol ; 42(2): 445-451, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31259364

RESUMO

The genus Rhinella is one of the most diverse groups of bufonid toads, currently composed by 93 valid species and naturally distributed throughout different Neotropical ecoregions. Here, we analyze nine Brazilian populations of toads representing species of the Rhinella margaritifera and Rhinella marina groups. These new data include the first description of the R. hoogmoedi and R. proboscidae karyotypes, as well as other taxonomically unresolved forms. Chromosomal analysis of the populations revealed pronounced chromosomal uniformity (2n=22), including the diploid number and chromosomal morphology. Three different NOR-bearing chromosomes were identified: in the subterminal region of pair 10q in R. hoogmoedi, Rhinella sp. 1 and Rhinella sp. 2, in subterminal region of 7p in R. proboscidae and Rhinella cf. margaritifera while in R. henseli and R. icterica was detected in interstitial region of 7p. Karyotypic uniformity of the genus permits the inference of interspecific chromosome homologies and evolutionary changes in the NOR-bearing chromosome may represent an informative character in species group level. The review of the cytogenetic data of the Rhinella species together with the new karyotypes reported here contributes to the understanding of the chromosomal evolution of these toads, which karyotypes are highly conserved despite the ample distribution of many forms.

7.
Cytogenet Genome Res ; 154(2): 79-85, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29544219

RESUMO

B chromosomes are supernumerary chromosomes found in the karyotypes of approximately 15% of all eukaryotic species. They present parasitic behavior and do not follow the standard Mendelian pattern of inheritance, resulting in an imbalance in gametogenesis. The evolutionary dynamics of B chromosomes is still unknown for many species, but studies indicate that the accumulation of repetitive sequences plays an important role in the differentiation of these elements. We analyzed morphology, frequency, and possible homologies amongst different B chromosomes found in an isolated Akodon montensis population in southern Brazil. Repetitive sequences (18S, 5S rDNA and telomeric sequences) were used to test for their accumulation on the supernumerary chromosomes and describe their localization in the species. The results indicate 4 different B chromosome morphotypes, and DNA libraries were generated for 3 of them. 18S rDNA was labelled polymorphically, except in the B chromosomes, whereas the 5S rDNA was located exclusively in an interstitial position on the long arm of chromosome 5. Chromosome painting with the B probes based on FISH revealed a homologous composition for all B chromosome morphotypes and no homology with the chromosomes in the A complement. B chromosomes found in this population may have a common origin and subsequently diversified in size and morphology.


Assuntos
Cromossomos de Mamíferos/genética , Sequências Repetitivas de Ácido Nucleico , Sigmodontinae/genética , Animais , Mapeamento Cromossômico/métodos , Coloração Cromossômica/métodos , Evolução Molecular , Feminino , Variação Genética , Masculino
8.
Lasers Med Sci ; 33(8): 1657-1666, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29687410

RESUMO

The aim of the present study was to assess, by means of Raman spectroscopy, the repair of complete surgical tibial fractures fixed with wire osteosynthesis (WO) treated or not with infrared laser (λ780 nm) or infrared light emitting diode (LED) (λ850 ± 10 nm) lights, 142.8 J/cm2 per treatment, associated or not to the use of mineral trioxide aggregate (MTA) cement. Surgical tibial fractures were created on 18 rabbits, and all fractures were fixed with WO and some groups were grafted with MTA. Irradiated groups received lights at every other day during 15 days, and all animals were sacrificed after 30 days, being the tibia removed. The results showed that only irradiation with either laser or LED influenced the peaks of phosphate hydroxyapatite (~ 960 cm-1). Collagen (~ 1450 cm-1) and carbonated hydroxyapatite (~ 1070 cm-1) peaks were influenced by both the use of MTA and the irradiation with either laser or LED. It is concluded that the use of either laser or LED phototherapy associated to MTA cement was efficacious on improving the repair of complete tibial fractures treated with wire osteosynthesis by increasing the synthesis of collagen matrix and creating a scaffold of calcium carbonate (carbonated hydroxyapatite-like) and the subsequent deposition of phosphate hydroxyapatite.


Assuntos
Fios Ortopédicos , Fixação Interna de Fraturas/métodos , Consolidação da Fratura/efeitos da radiação , Terapia com Luz de Baixa Intensidade/métodos , Análise Espectral Raman , Fraturas da Tíbia/radioterapia , Fraturas da Tíbia/cirurgia , Análise de Variância , Animais , Colágeno , Durapatita/química , Masculino , Coelhos , Tíbia/efeitos da radiação , Tíbia/cirurgia
9.
BMC Psychol ; 12(1): 236, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38671529

RESUMO

BACKGROUND: Studying individuals with varying symptoms, from mild to severe, can provide valuable insights into the spectrum of cognitive outcomes after COVID-19. We investigated the cognitive performance of adults who recovered from the novel coronavirus disease (COVID-19) without prior cognitive complaints, considering mild (not hospitalized), moderate (ward), and severe (intensive care unit) symptoms. METHODS: This cross-sectional study included 302 patients who recovered from COVID-19 (mild, n = 102; moderate, n = 102; severe, n = 98). We assessed intellectual quotient (IQ), attention, memory, processing speed, visual-constructive ability, as well as symptoms of depression, anxiety, and stress, at least eighteen months after infection. The mean length of hospitalization was Mdays=8.2 (SD = 3.9) and Mdays=14.4 (SD = 8.2) in the moderate and severe groups, respectively. RESULTS: Cognitive difficulties were present in all three groups: mild (n = 12, 11.7%), moderate (n = 40, 39.2%), and severe (n = 48, 48.9%). Using Multinomial Logistic Regression and considering the odds ratio, our results indicated that a one-point increase in sustained attention, visual memory, and working memory might decrease the odds of being categorized in the severe group by 20%, 24%, and 77%, respectively, compared to the mild group. CONCLUSIONS: Our findings provide empirical evidence regarding the long-term cognitive effects of COVID-19, particularly in individuals experiencing severe manifestations of the disease. We also highlighted the need for a comprehensive, multidimensional approach in rehabilitation programs to address the enduring cognitive impacts of COVID-19.


Assuntos
COVID-19 , Cognição , Humanos , COVID-19/psicologia , COVID-19/epidemiologia , Masculino , Feminino , Estudos Transversais , Pessoa de Meia-Idade , Adulto , Índice de Gravidade de Doença , Idoso , Atenção , Disfunção Cognitiva/psicologia , SARS-CoV-2 , Depressão/psicologia , Ansiedade/psicologia , Testes Neuropsicológicos
14.
Arq Bras Cardiol ; 2022 Sep 02.
Artigo em Português, Inglês | MEDLINE | ID: mdl-36074484

RESUMO

Clinical reasoning was born 2,500 years ago with Hippocrates, having evolved over the centuries, becoming a mixture of art and science. Several personalities throughout history have contributed to improving diagnostic accuracy. Nonetheless, diagnostic error is still common and causes a severe impact on healthcare systems. To face this challenge, several clinical reasoning models have emerged to systematize the clinical thinking process. This paper describes the history of clinical reasoning and current diagnostic reasoning methods, proposes a new clinical reasoning model, called Integrative Reasoning, and brings perspectives about the future of clinical reasoning.


O raciocínio clínico nasceu 2500 anos atrás com Hipócrates, tendo evoluído ao longo dos séculos, e se tornado uma mistura de arte e ciência. Várias personalidades ao longo da história contribuíram para melhorar a acurácia diagnóstica. Contudo, o erro diagnóstico é ainda comum e causa um grande impacto nos sistemas de saúde. Para lidar com esse desafio, vários modelos de raciocínio clínico surgiram para sistematizar o processo de pensamento clínico. Este artigo descreve a história do raciocínio clínico e os métodos atuais de raciocínio diagnóstico, propõe um novo modelo de raciocínio clínico chamado Raciocínio Integrativo, e traz perspectivas sobre o futuro do raciocínio clínico.

15.
Psicol Reflex Crit ; 35(1): 2, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34982281

RESUMO

Recent literature emphasizes how the specific stressors of the COVID-19 outbreak affect the general population and frontline professionals, including those conducting support or backup activities in health units, which can lead to vicarious traumatization. Vicarious traumatization has been used to describe negative emotional reactions in mental health professionals who assist or treat victims of traumatic events. Thus, the aim of this article is to report the actions used in the face of the psychological demands of professionals in a hospital, who were not on the frontline of COVID-19. We collected their sociodemographic information and checked the psychological impact using the depression, anxiety, and stress scale (DASS-21), which was followed by a psychoeducational program (topics related to COVID-19 control and prevention), and individual psychological care for the most severe cases. A total of 118 professionals participated in this study; they were between 20 and 67 years old. Mild to moderate anxiety was observed in 36.5% of the medical teams, 83.3% of the administrative staff, and 65.7% of general service workers, while stress symptoms were observed in 80.2%, 83.3%, and 59.9%, respectively. Depressive symptoms (35.3%) were more frequent in general service workers. The medical teams reported the benefits of primary psychological care, while the other professionals demanded more institutional support services related to the prevention and use of personal protective equipment. This study highlights relevant psychological demands that have repercussions on the daily lives of professionals. The psychoeducational program was considered positive regarding clarification actions. However, it was not perceived as effective in reducing fear, which may result from vicarious traumatization and requires other intervention modalities.

16.
Cien Saude Colet ; 27(3): 1205-1221, 2022 Mar.
Artigo em Português, Inglês | MEDLINE | ID: mdl-35293456

RESUMO

The need to request public health managers to ensure the right of access to medicines characterizes an administrative case and the method to do so is called the administrative route. This mixed method study aimed to analyze the perceptions of plaintiffs requesting medications by the administrative route about barriers to access medicines in the Brazilian public health sector. Data were gathered through focus groups and questionnaires. The results point to the interdependence of pharmaceutical services with the interfacing areas to ensure access. The barriers related to individuals reflect the commitment to develop citizenship, justifying the cost of the medicine to motivate the demand. Barriers to service provision include irregular availability of medicines, insufficient resources, and unsatisfactory quality of services. The difficulty in obtaining medical consultations and prescriptions originating in the public sector are barriers to the health sector. The barriers above the health sector are compliance with administrative procedures, corruption, and clientelism. The administrative route intensifies inequities in access to healthcare in Brazil.


A necessidade de recorrer ao gestor público de saúde para efetivar o direito ao acesso a medicamentos caracteriza a via administrativa. O estudo analisou as percepções dos usuários que acionaram a via administrativa sobre as barreiras para o acesso a medicamentos no setor público de saúde de uma capital brasileira. Foi realizado estudo de método misto com grupo focal, questionário com demandantes e descrição dos medicamentos demandados pela via administrativa. Os resultados apontam a interdependência da assistência farmacêutica com as áreas de interfaceamento para a garantia do acesso. As barreiras relativas aos indivíduos refletem o comprometimento do desenvolvimento da cidadania, justificando o custo do medicamento motivar a demanda. As barreiras à prestação dos serviços contemplam disponibilidade irregular dos medicamentos, insuficiência de recursos e qualidade insatisfatória dos serviços. A dificuldade para conseguir consultas médicas e a exigência da prescrição originada no setor público são barreiras ao setor saúde. As barreiras acima do setor saúde são cumprimento dos procedimentos administrativos, corrupção e clientelismo. A via administrativa intensifica as iniquidades no acesso à saúde no Brasil.


Assuntos
Acessibilidade aos Serviços de Saúde , Setor Público , Brasil , Grupos Focais , Humanos
18.
Toxicol Rep ; 8: 13-22, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33364179

RESUMO

The patented anti-inflammatory peptide TnP had its effectiveness recently confirmed in vivo in a murine model of multiple sclerosis and asthma. In this work, the safety of the TnP was evaluated in investigative toxicology tests using zebrafish (Danio rerio) as a model. We conducted the OECD #236 test to investigate effects of the TnP on the survival, hatching performance, and morphological formation of zebrafish embryos. After determining these endpoints, morphometric analysis termination of locomotion eartbeat rate in zebrafish larvae were evaluated to identify adverse effects such as neurotoxicity and cardiotoxicity. The results highlight a wide therapeutic index for TnP with non-lethal and safe doses rom 1 nM to 10 µM, without causing neurotoxicity or cardiotoxic effect. The low frequencyf abnormalities by TnP was associated with high safety of the molecule and the developing embryo's ability to process and eliminate it. TnP crossed the blood-brain barrier without disturbing the normal architecture of forebrain, midbrain and hindbrain. Our data reinforce the importance of zebrafish as an accurate investigative toxicology model to assess acute toxicity as well as cardiotoxicity and neurotoxicity of molecules in the preclinical phase of development.

19.
Pharmaceutics ; 13(7)2021 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-34371713

RESUMO

Doxorubicin (DOX), a chemotherapy drug successfully used in the therapy of various types of cancer, is currently associated with the mucositis development, an inflammation that can cause ulcerative lesions in the mucosa of the gastrointestinal tract, abdominal pain and secondary infections. To increase the safety of the chemotherapy, we loaded DOX into nanostructured lipid carriers (NLCs). The NLC-DOX was characterized by HPLC, DLS, NTA, Zeta potential, FTIR, DSC, TEM and cryogenic-TEM. The ability of NLC-DOX to control the DOX release was evaluated through in vitro release studies. Moreover, the effect of NLC-DOX on intestinal mucosa was compared to a free DOX solution in C57BL/6 mice. The NLC-DOX showed spherical shape, high drug encapsulation efficiency (84.8 ± 4.6%), high drug loading (55.2 ± 3.4 mg/g) and low average diameter (66.0-78.8 nm). The DSC and FTIR analyses showed high interaction between the NLC components, resulting in controlled drug release. Treatment with NLC-DOX attenuated DOX-induced mucositis in mice, improving shortening on villus height and crypt depth, decreased inflammatory parameters, preserved intestinal permeability and increased expression of tight junctions (ZO-1 and Ocludin). These results indicated that encapsulation of DOX in NLCs is viable and reduces the drug toxicity to mucosal structures.

20.
Int J Biol Macromol ; 175: 304-312, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33516854

RESUMO

Steam explosion can be used to pretreat lignocellulosic materials to decrease energy and chemical consumption during pulping to obtain environmentally friendly lignin and to improve lignin yield without changing its structure. The objective of this study was to evaluate the extraction of lignin from oil palm mesocarp fibers and sugarcane bagasse using steam explosion pretreatment followed by acetosolv. The biomasses were pretreated at 168 °C for a reaction time of 10 min. Steam explosion combined with acetosolv at lower severities was also carried out. Steam explosion followed by acetosolv increased the lignin yield by approximately 15% and 17% in oil palm mesocarp fibers and sugarcane bagasse, respectively. In addition, steam explosion decreased the reaction time of acetosolv four-fold while maintaining the lignin yield from sugarcane bagasse. Similar results were not obtained for oil palm mesocarp. High-purity and high-quality lignins were obtained using steam explosion pretreatment with structural characteristics similar to raw ones. Sugarcane bagasse lignin seems to be a better option for application in material science due its higher lignin yield and higher thermal stability. Our findings demonstrate that steam explosion is efficient for improving lignin yield and/or decreasing pulping severity.


Assuntos
Celulose/isolamento & purificação , Lignina/isolamento & purificação , Óleo de Palmeira/isolamento & purificação , Ácido Acético/química , Biomassa , Biotecnologia/métodos , Celulose/química , Etanol , Hidrólise , Lignina/química , Extratos Vegetais/isolamento & purificação , Saccharum/química , Vapor
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA