Caracterização morfológica de nanocristais de celulose por microscopia de força atômica

O isolamento de nanocristais de celulose (CNCs) de fibras vegetais é uma alternativa promissora para suaaplicação como reforço em matrizes poliméricas. A caracterização dos CNCs é fundamental para a confiabilidadeda técnica, além de determinar as aplicações possíveis a partir de cada tipo de fibra. A partir da técnicade microscopia de força atômica, um estudo da morfologia e distribuição dos CNCs de semente de manga,vagem de algaroba, pseudocaule da bananeira e fibra do mesocarpo de dendê foi realizado neste trabalho. OsCNCs foram obtidos via reação hidrolítica com ácido sulfúrico em concentrações que variaram de acordocom a fonte da fibra. Os resultados obtidos revelaram dimensões variando de 300 a 500 nm em comprimentoe 4 a 16 nm em diâmetro. A apresentação morfológica em forma de agulha demonstrou que o isolamento dasfibras de celulose em CNCs foi efetiva. A razão de aspecto associada à formação cilíndrica em agulha dosCNCs isolados evidenciou o alto potencial das fontes de dendê e de vagem de algaroba para o reforço de bionanocompósitos

Effect of combined therapy of virtual reality and transcranial direct current stimulation in children and adolescents with cerebral palsy: A study protocol for a triple-blinded randomized controlled crossover trial

Background: Transcranial direct current stimulation (tDCS) and therapy-based virtual reality (VR) have been investigated separately. They have shown promise as efficient and engaging new tools in the neurological rehabilitation of individuals with cerebral palsy (CP). However, the recent literature encourages investigation of the combination of therapy tools in order to potentiate clinic effects and its mechanisms. Methods: A triple-blinded randomised sham-controlled crossover trial will be performed. Thirty-six individuals with gross motor function of levels I to IV (aged 4–14 years old) will be recruited. Individuals will be randomly assigned to Group A (active first) or S (sham first): Group A will start with ten sessions of active tDSC combined with VR tasks. After a 1-month washout, this group will be reallocated to another ten sessions with sham tDCS combined with VR tasks. In contrast, Group S will carry out the opposite protocol, starting with sham tDCS. For the active tDCS the protocol will use low frequency tDCS [intensity of 1 milliampere (mA)] over the primary cortex (M1) area on the dominant side of the brain. Clinical evaluations (reaction times and coincident timing through VR, functional scales: Abilhand-Kids, ACTIVLIM-CP, Paediatric Evaluation of Disability Inventory-PEDI- and heart rate variability-HRV) will be performed at baseline, during, and after active and sham tDCS. Conclusion: tDCS has produced positive results in treating individuals with CP; thus, its combination with new technologies shows promise as a potential mechanism for improving neurological functioning. The results of this study may provide new insights into motor rehabilitation, thereby contributing to the better use of combined tDCS and VR in people with CP

Caracterização morfológica de nanocristais de celulose por microscopia de força atômica

RESUMO O isolamento de nanocristais de celulose (CNCs) de fibras vegetais é uma alternativa promissora para sua aplicação como reforço em matrizes poliméricas. A caracterização dos CNCs é fundamental para a confiabilidade da técnica, além de determinar as aplicações possíveis a partir de cada tipo de fibra. A partir da técnica de microscopia de força atômica, um estudo da morfologia e distribuição dos CNCs de semente de manga, vagem de algaroba, pseudocaule da bananeira e fibra do mesocarpo de dendê foi realizado neste trabalho. Os CNCs foram obtidos via reação hidrolítica com ácido sulfúrico em concentrações que variaram de acordo com a fonte da fibra. Os resultados obtidos revelaram dimensões variando de 300 a 500 nm em comprimento e 4 a 16 nm em diâmetro. A apresentação morfológica em forma de agulha demonstrou que o isolamento das fibras de celulose em CNCs foi efetiva. A razão de aspecto associada à formação cilíndrica em agulha dos CNCs isolados evidenciou o alto potencial das fontes de dendê e de vagem de algaroba para o reforço de bionanocompósitos

Development of the nanoimmunosensor-AQP461-70 for the highly specific and sensitive diagnosis of neuromyelitis optica spectrum disorders

As doenças do espectro da neuromielite óptica (ENMO) são caracterizadas por uma síndrome inflamatória do sistema nervoso central, caracterizada por neurite óptica e mielite transversa que afeta principalmente a medula espinal e os nervos ópticos. Estas síndromes têm forte indicativo de mecanismo de ação humoral (envolvendo anticorpos). O diagnóstico correto para ENMO é extremamente importante para melhorar o prognóstico dos pacientes acometidos por esta síndrome, por isso requer métodos altamente específicos e sensíveis. O teste CBA, método atual altamente recomendado para o diagnóstico do ENMO na detecção do anticorpo anti-AQP4, possui 100% de especificidade e 76% de sensibilidade. Neste trabalho, foram testados peptídeos das alças externas da proteína AQP4 (AQP461-70, AQP4131-140, AQP4141-150, e AQP4201-210), potenciais alvos do anti-AQP4, utilizando um nanoimunossensor de microscopia de força atômica para o desenvolvimento de um método de diagnóstico. Os resultados mostraram alta especificidade do nanoimunossensor-AQP461-70, tendo sido capaz de detectar o anti-AQP4 em amostras de IgGs purificadas do soro de pacientes do ENMO soropositivos com 100% de especificidade (95% IC 63,06-100,00), determinado pelo ponto de corte da força de adesão de 241,30 pN. Além disso, o nanoimunossensor distinguiu os pacientes do ENMO soropositivos dos indivíduos saudáveis, pacientes de esclerose múltipla e ENMO anti-AQP4 soronegativos, com sensibilidade de 81,25% (95% IC 56,50-99,43); resultado mais significante do que aquele obtido pelo método CBA. Os resultados indicam que as diferenças entre os fenótipos do ENMO estudados (anti-AQP4 soropositivo e anti-AQP4 soronegativo) se referem à epítopos específicos da doença. A ausência do anti-AQP4 em pacientes soronegativos pode ser devido à existência de uma sequência peptídica da proteína AQP4 diferente da AQP461-70 ou, ainda, à presença antígenos-alvo em outras proteínas que devem ser explorados para o diagnóstico deste fenótipo do ENMO.Neuromyelitis optica spectrum disorders (NMOSD) are inflammatory syndromes of the central nervous system, characterized by myelitis and optic neuritis events, which affect predominantly spinal cords and optic nerves. A precise diagnosis for NMOSD is crucial to improve patients\' prognostic, which requires highly specific and sensitive tests. The cell-based assay with a sensitivity of 76% and specificity of 100% is the most recommended test to detect anti-aquaporin-4 antibodies (AQP4-Ab). Here, four AQP4 external loop peptides (AQP461-70, AQP4131-140, AQP4141-150, and AQP4201-210) were tested with an atomic force microscopy nanoimmunosensor to develop a diagnostic assay. The results show the highest reactivity with AQP461-70-nanoimunosensor. This assay was effective in detecting AQP4-Ab in sera of NMOSD patients with 100% specificity (95% CI 63.06-100.00), determined by the cut-off adhesion force value of 241.3 pN. NMOSD patients were successfully discriminated from a set of healthy volunteers, patients with multiple sclerosis, and AQP4-Ab-negative patients. AQP461-70 sensitivity was 81.25% (95% CI 56.50-99.43). This sensitivity value was higher than the obtained by CBA method. The results with the AQP461-70-nanoimmunosensor indicate that the differences between NMOSD seropositive and seronegative phenotypes are related to disease-specific epitopes. The absence of AQP4-Ab in sera of NMOSD AQP4-Ab-negative patients may be interpreted by assuming the existence of another potential AQP4 peptide sequence or non-AQP4 antigens for NMOSD diagnosis purposes

In Vitro Antimicrobial Activity of Plant-Derived Diterpenes against Bovine Mastitis Bacteria

We evaluated the antibacterial activity of three diterpenes isolated from natural sources against a panel of microorganisms responsible for bovine mastitis. ent-Copalic acid (CA) was the most active metabolite, with promising MIC values (from 1.56 to 6.25 µg mL−1) against Staphylococcus aureus (ATCC and clinical isolate), Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus dysgalactiae. We conducted time-kill assays of CA against S. aureus, a commensal organism considered to be a ubiquitous etiological agent of bovine mastitis in dairy farms worldwide. In the first 12 h, CA only inhibited the growth of the inoculums (bacteriostatic effect), but its bactericidal effect was clearly noted thereafter (between 12 and 24 h). In conclusion, CA should be considered for the control of several Gram-positive bacteria related to bovine mastitis

Impact of the COVID-19 pandemic on patients with paediatric cancer in low-income, middle-income and high-income countries: a multicentre, international, observational cohort study

OBJECTIVES: Paediatric cancer is a leading cause of death for children. Children in low-income and middle-income countries (LMICs) were four times more likely to die than children in high-income countries (HICs). This study aimed to test the hypothesis that the COVID-19 pandemic had affected the delivery of healthcare services worldwide, and exacerbated the disparity in paediatric cancer outcomes between LMICs and HICs. DESIGN: A multicentre, international, collaborative cohort study. SETTING: 91 hospitals and cancer centres in 39 countries providing cancer treatment to paediatric patients between March and December 2020. PARTICIPANTS: Patients were included if they were under the age of 18 years, and newly diagnosed with or undergoing active cancer treatment for Acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin lymphoma, Wilms' tumour, sarcoma, retinoblastoma, gliomas, medulloblastomas or neuroblastomas, in keeping with the WHO Global Initiative for Childhood Cancer. MAIN OUTCOME MEASURE: All-cause mortality at 30 days and 90 days. RESULTS: 1660 patients were recruited. 219 children had changes to their treatment due to the pandemic. Patients in LMICs were primarily affected (n=182/219, 83.1%). Relative to patients with paediatric cancer in HICs, patients with paediatric cancer in LMICs had 12.1 (95% CI 2.93 to 50.3) and 7.9 (95% CI 3.2 to 19.7) times the odds of death at 30 days and 90 days, respectively, after presentation during the COVID-19 pandemic (p<0.001). After adjusting for confounders, patients with paediatric cancer in LMICs had 15.6 (95% CI 3.7 to 65.8) times the odds of death at 30 days (p<0.001). CONCLUSIONS: The COVID-19 pandemic has affected paediatric oncology service provision. It has disproportionately affected patients in LMICs, highlighting and compounding existing disparities in healthcare systems globally that need addressing urgently. However, many patients with paediatric cancer continued to receive their normal standard of care. This speaks to the adaptability and resilience of healthcare systems and healthcare workers globally

Twelve-month observational study of children with cancer in 41 countries during the COVID-19 pandemic

Childhood cancer is a leading cause of death. It is unclear whether the COVID-19 pandemic has impacted childhood cancer mortality. In this study, we aimed to establish all-cause mortality rates for childhood cancers during the COVID-19 pandemic and determine the factors associated with mortality