983 research outputs found
Polyhydroxyalkanoates Production by Mixed Microbial Culture under High Salinity
PTDC/BTA-BTA/30902/2017 UIDP/04378/2020 UIDB/04378/2020 LA/P/0140/2020The fishing industry produces vast amounts of saline organic side streams that require adequate treatment and disposal. The bioconversion of saline resources into value-added products, such as biodegradable polyhydroxyalkanoates (PHAs), has not yet been fully explored. This study investigated PHA production by mixed microbial cultures under 30 gNaCl/L, the highest NaCl concentration reported for the acclimatization of a PHA-accumulating mixed microbial culture (MMC). The operational conditions used during the culture-selection stage resulted in an enriched PHA-accumulating culture dominated by the Rhodobacteraceae family (95.2%) and capable of storing PHAs up to 84.1% wt. (volatile suspended solids (VSS) basis) for the highest organic loading rate (OLR) applied (120 Cmmol/(L.d)). This culture presented a higher preference for the consumption of valeric acid (0.23 ± 0.03 CmolHVal/(CmolX.h)), and the 3HV monomer polymerization (0.33 ± 0.04 CmmolHV/(CmmolX.h) was higher as well. As result, a P(3HB-co-3HV)) with high HV content (63% wt.) was produced in the accumulation tests conducted at higher OLRs and with 30 gNaCl/L. A global volumetric PHA productivity of 0.77 gPHA/(L.h) and a specific PHA productivity of 0.21 gPHA/(gX.h) were achieved. These results suggested the significant potential of the bioconversion of saline resources into value-added products, such as PHAs.publishersversionpublishe
Theory vs practice: synthesis of red lead following ancient recipes
The synthesis of red lead pigment (chemically lead oxide, Pb3O4) was carried out considering different starting lead compounds. The experimental procedure followed was established according to some recipes of ancient painting treatises and the knowledge of the phase transformation of lead oxides. The samples transformation was monitored by X-ray powder diffraction and selected samples were also characterized by scanning electron microscopy. The pure Pb3O4 phase was obtained for the transformation of PbO2 and 2PbCO3·Pb(OH)2. Morphological studies revealed that the material obtained from PbO2 presented the more homogeneous grain size distribution. The transformation of white lead Kremer Pigment resulted in a mixture of Pbr3O4 (major phase) and cerussite (PbCO3), leading to a sample with low crystallinity.info:eu-repo/semantics/publishedVersio
Mediação do trabalho prático de química no ensino universitário : uma experiência de integração no currículo
Impact of age, gender and body mass index on the efficacy of tranexamic acid in total knee arthroplasty
Background: Tranexamic acid (TXA) is effective and safe in decreasing blood loss and transfusion rate in total knee
arthroplasty (TKA). Few studies focused on the role of patients’ characteristics on the efficacy of TXA in TKA. The
purpose of this study was to conduct a retrospective analysis to investigate if age, gender and BMI influence the
efficacy of TXA in reducing perioperative blood loss in TKA.
Methods: We did an observational study including 366 consecutive patients undergoing TKA in Hospital Particular
do Algarve between January 2011 and April 2019 which were divided in two groups: intraoperative administration of
intravenous TXA (TXA Group) and no administration of TXA (Control Group). The perioperative blood loss between
groups and their relation with age, gender and BMI was compared.
Results: Of the 366 patients, 225 (61%) received TXA. In both groups, age did not correlate to the blood loss.
Women in the TXA group had less perioperative blood loss than in the control group. No such difference was found
for men. The normal weight group showed no difference in perioperative blood loss with or without TXA
administration. However, there was a statistically significant difference in the overweight and obese groups. The
mean perioperative blood loss was higher in the control group (854±342 ml) than in the TXA group (720±335 ml).
Conclusions: TXA administration is efficient in controlling TKA associated hemorrhage in overweight and obese
individuals and in women but it doesn’t have that effect in normal weight patients or in men.info:eu-repo/semantics/publishedVersio
Impact of age, gender and body mass index on the efficacy of tranexamic acid in total knee arthroplasty
Background: Tranexamic acid (TXA) is effective and safe in decreasing blood loss and transfusion rate in total knee arthroplasty (TKA). Few studies focused on the role of patients’ characteristics on the efficacy of TXA in TKA. The purpose of this study was to conduct a retrospective analysis to investigate if age, gender and BMI influence the efficacy of TXA in reducing perioperative blood loss in TKA.Methods: We did an observational study including 366 consecutive patients undergoing TKA in Hospital Particular do Algarve between January 2011 and April 2019 which were divided in two groups: intraoperative administration of intravenous TXA (TXA Group) and no administration of TXA (Control Group). The perioperative blood loss between groups and their relation with age, gender and BMI was compared.Results: Of the 366 patients, 225 (61%) received TXA. In both groups, age did not correlate to the blood loss. Women in the TXA group had less perioperative blood loss than in the control group. No such difference was found for men. The normal weight group showed no difference in perioperative blood loss with or without TXA administration. However, there was a statistically significant difference in the overweight and obese groups. The mean perioperative blood loss was higher in the control group (854±342 ml) than in the TXA group (720±335 ml).Conclusions: TXA administration is efficient in controlling TKA associated hemorrhage in overweight and obese individuals and in women but it doesn’t have that effect in normal weight patients or in men
A multivariate approach for multi-step demand forecasting in assembly industries: Empirical evidence from an automotive supply chain
PreprintDemand forecasting works as a basis for operating, business and production planning decisions in many supply chain contexts. Yet, how to accurately predict the manufacturer's demand for components in the presence of end-customer demand uncertainty remains poorly understood. Assigning the proper order quantities of components to suppliers thus becomes a nontrivial task, with a significant impact on planning, capacity and inventory-related costs. This paper introduces a multivariate approach to predict manufacturer's demand for components throughout multiple forecast horizons using different leading indicators of demand shifts. We compare the autoregressive integrated moving average model with exogenous inputs (ARIMAX) with Machine Learning (ML) models. Using a real case study, we empirically evaluate the forecasting and supply chain performance of the multivariate regression models over the component's life-cycle. The experiments show that the proposed multivariate approach provides superior forecasting and inventory performance compared with traditional univariate benchmarks. Moreover, it reveals applicable throughout the component's life-cycle, not just to a single stage. Particularly, we found that demand signals at the beginning of the life-cycle are predicted better by the ARIMAX model, but it is outperformed by ML-based models in later life-cycle stages.INCT-EN - Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção(UIDB/00319/2020
Jatrophane and lathyrane diterpenoids from Euphorbia hyberna L
A new diterpene tetraester, from the jatrophane family, and two new diterpene triesters, with a lathyrane skeleton, have been
isolated from the chloroform extract of the roots of Euphorbia hyberna L. The structures of these compounds have been established
by spectroscopic methods, including 2D NMR experiments.info:eu-repo/semantics/publishedVersio
Chemical constituents of Euphorbia hyberna L. (Euphorbiaceae)
Chemical investigation of the aerial part and the roots of Euphorbia hyberna
L. subs. hyberna. resulted in the isolation and identification of four triterpenoids
(3�-O-octadecanoyllupeol (1), glut-5-en-3�-ol (2), 24-methylenecicloartan-3�-ol
(3) and cicloart-23-ene-3�,25-diol (6)) along with the phenolic compounds ellagic
acid (4) and 3,30
-di-O-methylellagic acid (7). Although these are all known
compounds, this is the first report of their isolation from this plant.
Their structures were elucidated on the basis of spectral methods, including 2D
NMR experiences, and confirmed by comparing with the literature data.info:eu-repo/semantics/publishedVersio
Validity and Reliability of the Portuguese Version of the Dispositional Flow Scale-2 in Exercise
This study aimed to analyze the factorial validity and reliability of the Portuguese version of the Dispositional Flow Scale-2 (DFS-2; Jackson and Eklund, 2002) with a sample of 1437 exercise participants, a population in which flow has not been widely studied. The CFA adjustment indices of the nine-factor first-order structure were acceptable. Both the time transformation and loss of self-consciousness scales presented modest correlations with the remaining flow dimensions. Internal consistency estimates were satisfactory for all flow factors. Except for time transformation, all the dispositional flow scales correlated with perceived competence in and enjoyment of exercise. These findings provide support for the validity and reliability of the Portuguese version of the DFS-2 for measuring flow experiences in exercise. The use of the nine flow factor level scores rather than a single global score is recommended
- …