1,665 research outputs found
Herbicidal activity of volatiles from coriander, winter savory, cotton lavender, and thyme isolated by hydrodistillation and supercritical fluid extraction
The volatiles from Coriandrum sativum L., Satureja montana L., Santolina chamaecyparissus L., and Thymus vulgaris L. were isolated by hydrodistillation (essential oil) and supercritical fluid extraction (volatile oil). Their effect on seed germination and root and shoot growth of the surviving seedlings of four crops (Zea mays L., Triticum durum L., Pisum sativum L., and Lactuca sativa L.) and two weeds (Portulaca oleracea L. and Vicia sativa L.) was investigated and compared with those of two synthetic herbicides, Agrocide and Prowl. The volatile oils of thyme and cotton lavender seemed to be promising alternatives to the synthetic herbicides because they were the least injurious to the crop species. The essential oil of winter savory, on the other hand, affected both crop and weeds and can be appropriate for uncultivated fields
Addressing the non-linearity and singularity phenomena of stress-based optimal design of material microstructures
Material design is an active research field since composites have met increasingly interest, for instance, in lightweight construction as it happens in aerospace industry. One assumes in the present work a given macroscopic stress or strain field (one that may occur at a certain point of a macro-structure) and computes through homogenization the micro-stress distribution across the two (weaker and stronger) composite constituents mixed in a unit-cell domain which is representative of a periodic heterogeneous material. Stress gradients depend a lot of design details but typically the stress field is highly non-linear. In the frame of finite element models for material microstructures one pursues here an investigation about mesh convergence. Since stress distribution is strongly design dependent, that motivates one to pursue optimal design of the material microstructure to comply with admissible stress criteria. The inverse homogenization method using density-based topology optimization is applied here for such purpose. This is quite a challenge not only because of the aforementioned non-linearity of the stress field but also due to the singularity phenomena which one overcomes using standard relaxation techniques. Some preliminary results are obtained in order to get some insight into the fine structure of composite materials and the influence of the stresses therein
Buried dislocation networks designed to organize the growth of III-V semiconductor nanostructures
We first report a detailed transmission electron microscopy study of
dislocation networks (DNs) formed at shallowly buried interfaces obtained by
bonding two GaAs crystals between which we establish in a controlled manner a
twist and a tilt around a k110l direction. For large enough twists, the DN
consists of a twodimensional network of screw dislocations accommodating mainly
the twist and of a one-dimensional network of mixed dislocations accommodating
mainly the tilt. We show that in addition the mixed dislocations accommodate
part of the twist and we observe and explain slight unexpected disorientations
of the screw dislocations with respect to the k110l directions. By performing a
quantitative analysis of the whole DN, we propose a coherent interpretation of
these observations which also provides data inaccessible by direct experiments.
When the twist is small enough, one screw subnetwork vanishes. The surface
strain field induced by such DNs has been used to pilot the lateral ordering of
GaAs and InGaAs nanostructures during metal-organic vapor phase epitaxy. We
prove that the dimensions and orientations of the nanostructures are correlated
with those of the cells of the underlying DN and explain how the interface
dislocation structure governs the formation of the nanostructures
Effect of place of birth and transport on morbidity and mortality of preterm newborns
OBJETIVO: Verificar a influência do local de nascimento e do transporte sobre a morbimortalidade de recém-nascidos prematuros na Região Sul do Brasil. MÉTODOS: Estudo de coorte com recém-nascidos prematuros transferidos para a unidade de tratamento intensivo de referência (grupo transporte = 61), tendo sido acompanhados até a alta. Os dados sobre o atendimento no hospital de origem e transporte foram obtidos no momento da internação. Esse grupo foi comparado com neonatos da maternidade de referência, pareados por idade gestacional (grupo controle = 123), tendo como desfecho primário o óbito e desfechos secundários as alterações da glicemia, temperatura e saturação de oxigênio no momento da internação e a incidência de enterocolite necrosante, displasia broncopulmonar e sepses. Na associação entre as variáveis e o desfecho, foi utilizado o risco relativo. Foi adotado um nível de significância de α = 5% e β = 90%. RESULTADOS: A distância média percorrida foi de 91 km. A idade gestacional média foi de 34 semanas. Entre os recém-nascidos transferidos, 23% (n = 14) não tiveram atendimento pediátrico na sala de parto. No transporte, 33% dos recém-nascidos foram acompanhados por pediatra, e os equipamentos utilizados foram: incubadora (57%), bomba de infusão (13%), oxímetro (49%) e aparelho para aferição da glicemia (21%). O grupo transporte apresentou maior incidência de hiperglicemia, risco relativo (RR) = 3,2 (2,3-4,4), hipoglicemia, RR = 2,4 (1,4-4,0), hipertermia, RR = 2,5 (1,6-3,9), e hipoxemia, RR = 2,2 (1,6-3,0). Foram observados 18% de óbitos no grupo dos transferidos e 8,9% no grupo controle, RR = 2,0 (1,0-2,6). CONCLUSÕES: A pesquisa expõe deficiências no atendimento e transporte dos recém-nascidos, sendo necessária uma melhor organização do atendimento perinatal e do transporte na região nordeste do Rio Grande do Sul.OBJECTIVE: To evaluate the effect of place of birth and transport on morbidity and mortality of preterm newborns in the southern region of Brazil. METHODS: This cohort study included preterm newborns transported to a reference intensive care unit (transport group = 61) and followed up until discharge. Data about care in hospital of origin and transport were obtained at admission. This group was compared with infants born in the maternity ward of the reference hospital paired according to gestational age (control group = 123). Primary outcome was death, and secondary outcomes were changes in blood glucose, temperature and oxygen saturation at admission and the incidence of necrotizing enterocolitis, bronchopulmonary dysplasia and sepsis. Relative risk (RR) was used to evaluate the association between variables and outcome. The level of significance was set at α = 5% and β = 90%. RESULTS: Mean travel distance was 91 km. Mean gestational age was 34 weeks. Of the neonates in the transport group, 23% (n = 14) did not receive pediatric care in the delivery room. During transportation, 33% of newborns were accompanied by a pediatrician, and the equipment available was: incubator (57%), infusion pump (13%), oximeter (49%) and device for blood glucose test (21%). The transport group had a greater incidence of hyperglycemia (RR = 3.2; 2.3-4.4), hypoglycemia (RR = 2.4; 1.4-4.0), hyperthermia (RR = 2.5; 1.6-3.9), and hypoxemia (RR = 2.2; 1.6-3.0). The percentage of deaths was 18% in the transport group and 8.9% in the control group (RR = 2.0; 1.0-2.6). CONCLUSIONS: This study revealed deficiencies in neonatal care and transport. Perinatal care and transport should be better organized in the northeastern region of Rio Grande do Sul, Brazil
Eugenol β-amino/β-alkoxy alcohols with selective anticancer activity
Eugenol, 4-allyl-2-methoxyphenol, is the main constituent of clove essential oil and has demonstrated relevant biological activity, namely anticancer activity. Aiming to increase this activity, we synthesized a series of eugenol β-amino alcohol and β-alkoxy alcohol derivatives, which were then tested against two human cancer cell lines, namely gastric adenocarcinoma cells (AGS) and lung adenocarcinoma cells (A549). An initial screening was performed to identify the most cytotoxic compounds. The results demonstrated that three β-amino alcohol derivatives had anticancer activity that justified subsequent studies, having been shown to trigger apoptosis. Importantly, the most potent molecules displayed no appreciable toxicity towards human noncancer cells. Structure-activity relationships show that changes in eugenol structure led to enhanced cytotoxic activity and can contribute to the future design of more potent and selective drugs.This research was funded by FCT under project PTDC/ASP-AGR/30154/2017 (PO-CI-01-0145-
FEDER-030154) of COMPETE 2020, co-financed by FEDER and EU. FCT-Portugal and FEDERCOMPETE/
QREN-EU also gave financial support to the research centres CQ/UM (UIDB/00686/2020) and REQUIMTE (UIDB/50006/2020). The NMR spectrometer Bruker Avance III 400 (part of the National NMR
Network) was financed by FCT and FEDER. Renato B. Pereira acknowledges PRIMA Foundation (H2020-
PRIMA 2018—Section 2, Project MILKQUA) and FCT (PTDC/QUI-QFI/2870/2020) for the funding
Optical fiber sensors based on sol-gel materials: design, fabrication and application in concrete structures
Optical fiber sensing systems have been widely developed for several fields such as biomedical diagnosis, food technology, military and industrial applications and civil engineering. Nowadays, the growth and advances of optical fiber sensors (OFS) are focused on the development of novel sensing concepts and transducers as well as sensor cost reduction. This review provides an overview of the state-of-the-art of OFS based on sol-gel materials for diverse applications with particular emphasis on OFS for structural health monitoring of concrete structures. The types of precursors used in the development of sol-gel materials for OFS functionalization to monitor a wide range of analytes are debated. The main advantages of OFS compared to other sensing systems such as electrochemical sensors are also considered. An interdisciplinary review to a broad audience of engineers and materials scientists is provided and the relationship between the chemistry of sol-gel material synthesis and the development of OFS is considered. To the best of the authors' knowledge, no review manuscripts were found in which the fields of sol-gel chemistry and OFS are correlated. The authors consider that this review will serve as a reference as well as provide insights for experts into the application of sol-gel chemistry and OFS in the civil engineering field. (c) The Royal Society of Chemistry
Synthesis, computational and nanoencapsulation studies on eugenol-derived insecticides
A new set of alkoxy alcohols were synthesised by reaction of eugenol oxirane with aliphatic and aromatic alcohols. These eugenol derivatives were evaluated against their effect upon the viability of the insect cell line Sf9 (Spodoptera frugiperda). The most promising compounds, 4-(3-(tert-butoxy)-2-hydroxypropyl)-2-methoxyphenol and 4-(2-((4-fluorobenzyl)oxy)-3-hydroxypropyl)-2-methoxyphenol were submitted to in silico assays to predict possible targets. Throught an Inverted Virtual Screening approach, 23 common pesticide targets were screened and the top 2 targets predicted were further analyzed through molecular dynamics simulations and free energy calculations. In addition, these eugenol derivatives were subjected to encapsulation and release assays using liposome-based nanosystems of egg phosphatidylcholine/cholesterol (7:3), with encapsulation efficiencies higher than 90% and release profiles well described by both Korsmeyer-Peppas and Weibull models.This research was funded by the project PTDC/ASP-AGR/30154/2017 (POCI-01-0145-FEDER-030154) of the COMPETE 2020 program, co-financed by the FEDER and the European Union. The authors also acknowledge the Foundation for Science and Technology (FCT, Portugal) and FEDERCOMPETE-QREN-EU for financial support to the research centers CQ-UM (UID/QUI/00686/2021), CF-UM-UP (UIDB/04650/2021) and REQUIMTE (UIDB/50006/2020). Renato B. Pereira acknowledges the PRIMA Foundation (H2020-PRIMA 2018-Section 2, Project MILKQUA) and FCT (PTDC/QUI-QFI/2870/2020) for the funding. The NMR spectrometer Bruker Avance III 400 was a part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT
Concurrent agreement between an anthropometric model to predict thigh volume and dual-energy X-Ray absorptiometry assessment in female volleyball players aged 14-18 years
A variety of performance outputs are strongly determined by lower limbs volume and composition in children and adolescents. The current study aimed to examine the validity of thigh volume (TV) estimated by anthropometry in late adolescent female volleyball players. Dual-energy X-ray absorptiometry (DXA) measures were used as the reference method. Total and regional body composition was assessed with a Lunar DPX NT/Pro/MD+/Duo/Bravo scanner in a cross-sectional sample of 42 Portuguese female volleyball players aged 14-18 years (165.2 ± 0.9 cm; 61.1 ± 1.4 kg). TV was estimated with the reference method (TV-DXA) and with the anthropometric method (TV-ANTH). Agreement between procedures was assessed with Deming regression. The analysis also considered a calibration of the anthropometric approach. The equation that best predicted TV-DXA was: -0.899 + 0.876 × log10 (body mass) + 0.113 × log10 (TV-ANTH). This new model (NM) was validated using the predicted residual sum of squares (PRESS) method (R2PRESS = 0.838). Correlation between the reference method and the NM was 0.934 (95%CI: 0.880-0.964, Sy∙x = 0.325 L). A new and accurate anthropometric method to estimate TV in adolescent female volleyball players was obtained from the equation of Jones and Pearson alongside with adjustments for body mass.info:eu-repo/semantics/publishedVersio
Valorization of Oleuropein via Tunable Acid-Promoted Methanolysis
The acid-promoted methanolysis of oleuropein was studied using a variety of homogeneous and heterogeneous acid catalysts. Exclusive cleavage of the acetal bond between the glucoside and the monoterpene subunits or further hydrolysis of the hydroxytyrosol ester and subsequent intramolecular rearrangement were observed upon identification of the most efficient catalyst and experimental conditions. Furthermore, selected conditions were tested using oleuropein under continuous flow and using a crude mixture extracted from olive leaves under batch. Formation of (−)-methyl elenolate was also observed in this study, which is a reported precursor for the synthesis of the antihypertensive drug (−)-ajmalicine.Centro de Investigación y Desarrollo en Ciencias Aplicada
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