1,226 research outputs found
Biogeographic origin of the common green lacewings (Neuroptera, Chrysopidae) of the Azores archipelago, through morphology analysis
Due to a great dispersal ability and small size, insects are probably among the first island colonisers. Chrysoperla carnea sensu lato was for long considered the sole member of the Chrysopidae family in the Azores (Portugal) since it has been regarded as a complex of sibling species in Europe and North America. Its separation into different morphotypes is based on a set of pre-determined morphological traits. Their analysis leads to appraise Azorean Chrysopidae origin, comparing insular and mainland populations. Two outside
âcarnea complexâ species, namely the Nearctic C. rufilabris and the Neotropical C.
externa, were also examined to validate the method. Data analysis resulted in grouping
separately the two out-group species as expected, and clearly joins insular and Palaearctic specimens of C. lucasina. Chrysoperla agilis, although known to be present in the Azores through courtship song analysis, is morphologically similar to the two other Palaearctic species, which confirms the continental Palaearctic origin of the common green lacewings in the Azores. Madeira has probably served as a stepping-stone to the Azorean colonisation
Application of edible alginate films with pineapple peel active compounds on beef meat preservation
Alginate-based edible films containing natural antioxidants from pineapple peel were
applied in the microbial spoilage control, color preservation, and barrier to lipid oxidation of
beef steaks under storage at 4 C for five days. Di erent stabilization methods of pineapple peel
compounds were used before incorporation into alginate films, including extracted compounds with
an hydroalcoholic solvent encapsulated in microparticles, microparticles produced by spray-drying
pineapple peel juice, and particles obtained by milling freeze dried pineapple peel. Bioactive films
exhibited higher antioxidant activity (between 0.15 mol to 0.35 mol FeSO4.7H2O/g dried film) than
the alginate film without these compounds (0.02 mol FeSO4.7H2O/g dried film). Results showed
that control films without active compounds had no significant e ect on decreasing the microbial load
of aerobic mesophilic and Pseudomonas spp., while the films containing encapsulated hydroalcoholic
extract showed a significant inhibitory e ect on microbial growth of meat at two days of storage.
Alginate films containing peel encapsulated extract were e ective for maintaining the color hue and
intensity of red beef meat samples. Pineapple peel antioxidants have the potential to retard lipid
oxidation in meat samples, and the possibility of incorporation of a higher amount of pineapple peel
bioactive compounds in the films should be investigatedinfo:eu-repo/semantics/publishedVersio
Sustainable design of prefabricated solutions for the rehabilitation of ancient buildings
"Green design, materials and manufacturing processes", ISBN 978-1-138-00046-9A wood-based âkit-of-partsâ for the rehabilitation of existing buildings is under development. The aim is to merge the benefits of the standardized manufacture, with the flexibility needed to suit the specific requirements of the built heritage. The proposed system should be reversible, flexible and adaptable, while ensuring the adequate structural, thermal and acoustic performances. Mechanical joints, reversible if possible, should be used for the connections with the existing construction. Light solutions, allowing on site adjustment and future material separation are preferable.The research project presented in this paper is part of "WoodenQuark n.Âș 2011/21635" from the Portu-guese financing programme "Quadro de ReferĂȘncia EstratĂ©gico Nacional".
The authors also acknowledge the cooperation of "SRU - Sociedade de Reabilitação Urbana do Porto Vivo"
Insight into the effects of solvent treatment of natural fibers prior to structural composite casting: chemical, physical and mechanical evaluation
This paper presents an optimized washing protocol for as-received natural fibers, prior to large-scale composite manufacturing, for the structural strengthening of historic masonry. The aim was to achieve a simple protocol for standard cleaning of fiber surfaces from low molecular weight constituents that may be detrimental towards interfacial strength without damaging the fibers. The proposed procedure employs the application of the solvent sequence: ethanol, acetone, hexane, with optimized incubation times and stirring conditions. Additionally, this procedure may change the surface of the fiber, thereby enhancing the durability of the fiber-matrix interface. The washing protocol resulted in an increase of tensile strength by 56%, 52% and 22% for flax, hemp and sisal fibers, respectively, as compared to the corresponding non-washed fibers, without loss of elongation. The static contact angle measurements confirmed exposure of a higher fraction of the hydrophilic crystalline cellulose, with a higher wettability observed after washing protocols.This work was partly financed by the Portuguese Foundation for Science and Technology (FCT/MCTES) through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE) under reference UIDB/04029/2020.
IPC acknowledges the support of FCT through National Funds References UIDB/05256/2020 and
UIDP/05256/2020. The authors wish to acknowledge FCT for the PhD scholarship granted to the
first author (SFRH/BD/144106/2019)
Microencapsulation of beta-carotene by spray drying effect of wall material concentration and drying inlet temperature
Research ArticleCarotenoids are a class of natural pigments found mainly in fruits and vegetables. Among them, -carotene is regarded the most
potent precursor of vitamin A. However, it is susceptible to oxidation upon exposure to oxygen, light, and heat, which can result in
loss of colour, antioxidant activity, and vitamin activity.Thus, the objective of thiswork was to study themicroencapsulation process
of -carotene by spray drying, using arabic gum as wall material, to protect it against adverse environmental conditions. This was
carried out using the response surfacemethodology coupled to a central composite rotatable design, evaluating simultaneously the
effect of drying air inlet temperature (110-200âC) and the wall material concentration (5-35%) on the drying yield, encapsulation
efficiency, loading capacity, and antioxidant activity. In addition, morphology and particles size distribution were evaluated.
Scanning electron microscopy images have shown that the particles were microcapsules with a smooth surface when produced
at the higher drying temperatures tested,most of them having a diameter lower than 10 m.The conditions that enabled obtaining
simultaneously arabic gummicroparticles with higher -carotene content, higher encapsulation efficiency, and higher drying yield
were a wall material concentration of 11.9% and a drying inlet temperature of 173âC.The systematic approach used for the study of
-carotene microencapsulation process by spray drying using arabic gum may be easily applied for other core and wall materialsinfo:eu-repo/semantics/publishedVersio
In vitro fermentation of selected xylo-oligosaccharides by piglet intestinal microbiota
The objective of this study was to compare the in vitro fermentability of xylo-oligosaccharides (XOS) with different degrees of polymerisation
(DP) by the intestinal digesta collected in three distinct intestinal sections of the porcine intestinal tract: ileum, caecum, and distal colon.
The studied oligosaccharides included commercial short-chain XOS (DP 2e5), and medium-chain (DP 2e14) and long-chain (DP 2e25) XOS
obtained by autohydrolysis of breweryâs spent grain (BSG), corn cobs (CC) and Eucalyptus globulus wood (EUC). The oligosaccharide and
monosaccharide consumption, lactate and short-chain fatty acids concentrations were correlated with shifts on PCR titres of Bacteroides/
Prevotella, Bifidobacterium and Lactobacillus/Pediococcus populations, by using group- and genus-specific primers.
All tested XOS were extensively fermented by the piglet ileal, caecal and colonic microbiota. The rate of consumption of medium- and longchain
XOS was notably reduced in the fermentations by the ileal inoculum as compared to commercial XOS. EUC XOS, CC XOS and commercial
XOS supported an enhancement of bifidobacteria and lactobacilli replication in a first stage of the fermentations. Apparently this
stimulation was not selective, because Bacteroides/Prevotella replication increased in a second stage of the fermentations, coincident in time
with the highest consumption rates of some XOS mixtures tested. Mostly due to the slow fermentability by the ileal microbiota, medium-chain
and long-chain XOS mixtures can be regarded as promising functional candidates suitable to act as distally fermentable substrate
Inflammatory paradoxical reaction occurring in tuberculosis patients treated with haart and rifampicin
Sources of uncertainty in the closed-loop supply chain of lithium-ion batteries for electric vehicles
Due to increasing demand for electric vehicles and short innovation circles of battery, production, and recycling technology, different uncertainties need to be faced at different stages of the supply chain. However, a qualitative analysis of the uncertainties and their sources is missing. Therefore, in this paper the authors propose an empirical approach to the identification of uncertainty occurring in the closed-loop supply chain of lithium-ion batteries from electric vehicles (uncertainty in supply, process, demand, control, and environmental uncertainty). The investigation methodology consists of a content analysis of press media documents related to electric vehicles and the automotive industry. The final content analysis comprises 102 evidences of uncertainty. Consequently, the evidences of uncertainty found are classified in a spectrum between statistical uncertainty and total ignorance (levels of uncertainty). Graphs and data are described to provide detailed information. The results signal predominant environmental uncertainty besides the uncertainty within control and supply of the closed-loop. A conclusion on the investigation shows cobalt as a raw material responsible for increasing uncertainty (boomerang effect). Additionally, the content analysis evidences uncertainty with the availability, quantity, stock control policies, government regulations, and political instability with cobalt, lithium, and nickel.publishersversionpublishe
Raman spectrometry as a tool for an online control of a phototrophic biological nutrient removal process
UIDP/04378/2020 UIDB/04378/2020 PD/BD/114574/2016Real-time bioprocess monitoring is crucial for efficient operation and effective bioprocess control. Aiming to develop an online monitoring strategy for facilitating optimization, fault detection and decision-making during wastewater treatment in a photo-biological nutrient removal (photo-BNR) process, this study investigated the application of Raman spectroscopy for the quantifi-cation of total organic content (TOC), volatile fatty acids (VFAs), carbon dioxide (CO2 ), ammonia (NH3 ), nitrate (NO3 ), phosphate (PO4 ), total phosphorus (total P), polyhydroxyalkanoates (PHAs), total carbohydrates, total and volatile suspended solids (TSSs and VSSs, respectively). Specifically, partial least squares (PLS) regression models were developed to predict these parameters based on Raman spectra, and evaluated based on a full cross-validation. Through the optimization of spectral pre-processing, Raman shift regions and latent variables, 8 out of the 11 parameters that were investigatedânamely TOC, VFAs, CO2, NO3, total P, PHAs, TSSs and VSSsâcould be predicted with good quality by the respective Raman-based PLS calibration models, as shown by the high coefficient of determination (R2 > 90.0%) and residual prediction deviation (RPD > 5.0), and relatively low root mean square error of cross-validation. This study showed for the first time the high potential of Raman spectroscopy for the online monitoring of TOC, VFAs, CO2, NO3, total P, PHAs, TSSs and VSSs in a photo-BNR reactor.publishersversionpublishe
Delignification of Cistus ladanifer biomass by organosolv and alkali processes
Residues of Cistus ladanifer obtained after commercial steam distillation for essential oil
production were evaluated to produce cellulose enriched solids and added-value lignin-derived
compounds. The delignification of extracted (CLRext) and extracted and hydrothermally pretreated
biomass (CLRtreat) was studied using two organosolv processes, ethanol/water mixtures (EO), and
alkali-catalyzed glycerol (AGO), and by an alkali (sodium hydroxide) process (ASP) under different
reaction conditions. The phenolic composition of soluble lignin was determined by capillary zone
electrophoresis and by Py-GC/MS, which was also used to establish the monomeric composition of
both the delignified solids and isolated lignin. The enzymatic saccharification of the delignified solids
was also evaluated. The ASP (4% NaOH, 2 h) lead to both the highest delignification and enzymatic
saccharification (87% and 79%, respectively). A delignification of 76% and enzymatic hydrolysis
yields of 72% were obtained for AGO (4% NaOH) while EO processes led to lower delignification
(maximum lignin removal 29%). The residual lignin in the delignified solids were enriched in Gand
H-units, with S-units being preferentially removed. The main phenolics present in the ASP and
AGO liquors were vanillic acid and epicatechin, while gallic acid was the main phenolic in the EO
liquors. The results showed that C. ladanifer residues can be a biomass source for the production of
lignin-derivatives and glucan-rich solids to be further used in bioconversion processesinfo:eu-repo/semantics/publishedVersio
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