1,257 research outputs found
Observational Characterization of the Downward Atmospheric Longwave Radiation at the Surface in the City of São Paulo
This work describes the seasonal and diurnal variations of downward longwave atmospheric irradiance (LW) at the surface in São Paulo, Brazil, using 5-min-averaged values of LW, air temperature, relative humidity, and solar radiation observed continuously and simultaneously from 1997 to 2006 on a micrometeorological platform, located at the top of a 4-story building. An objective procedure, including 2-step filtering and dome emission effect correction, was used to evaluate the quality of the 9-yr-long LW dataset. The comparison between LW values observed and yielded by the Surface Radiation Budget project shows spatial and temporal agreement, indicating that monthly and annual average values of LW observed in one point of São Paulo can be used as representative of the entire metropolitan region of São Paulo. The maximum monthly averaged value of the LW is observed during summer (389 ± 14 W m-2; January), and the minimum is observed during winter (332 ± 12 W m-2; July). The effective emissivity follows the LW and shows a maximum in summer (0.907 ± 0.032; January) and a minimum in winter (0.818 ± 0.029; June). The mean cloud effect, identified objectively by comparing the monthly averaged values of the LW during clear-sky days and all-sky conditions, intensified the monthly average LW by about 32.0 ± 3.5 W m-2 and the atmospheric effective emissivity by about 0.088 ± 0.024. In August, the driest month of the year in São Paulo, the diurnal evolution of the LW shows a minimum (325 ± 11 W m-2) at 0900 LT and a maximum (345 ± 12 W m-2) at 1800 LT, which lags behind (by 4 h) the maximum diurnal variation of the screen temperature. The diurnal evolution of effective emissivity shows a minimum (0.781 ± 0.027) during daytime and a maximum (0.842 ± 0.030) during nighttime. The diurnal evolution of all-sky condition and clear-sky day differences in the effective emissivity remain relatively constant (7% ± 1%), indicating that clouds do not change the emissivity diurnal pattern. The relationship between effective emissivity and screen air temperature and between effective emissivity and water vapor is complex. During the night, when the planetary boundary layer is shallower, the effective emissivity can be estimated by screen parameters. During the day, the relationship between effective emissivity and screen parameters varies from place to place and depends on the planetary boundary layer process. Because the empirical expressions do not contain enough information about the diurnal variation of the vertical stratification of air temperature and moisture in São Paulo, they are likely to fail in reproducing the diurnal variation of the surface emissivity. The most accurate way to estimate the LW for clear-sky conditions in São Paulo is to use an expression derived from a purely empirical approach
MUMAL: multivariate analysis in shotgun proteomics using machine learning techniques.
BACKGROUND: The shotgun strategy (liquid chromatography coupled with tandem mass spectrometry) is widely applied for identification of proteins in complex mixtures. This method gives rise to thousands of spectra in a single run, which are interpreted by computational tools. Such tools normally use a protein database from which peptide sequences are extracted for matching with experimentally derived mass spectral data. After the database search, the correctness of obtained peptide-spectrum matches (PSMs) needs to be evaluated also by algorithms, as a manual curation of these huge datasets would be impractical. The target-decoy database strategy is largely used to perform spectrum evaluation. Nonetheless, this method has been applied without considering sensitivity, i.e., only error estimation is taken into account. A recently proposed method termed MUDE treats the target-decoy analysis as an optimization problem, where sensitivity is maximized. This method demonstrates a significant increase in the retrieved number of PSMs for a fixed error rate. However, the MUDE model is constructed in such a way that linear decision boundaries are established to separate correct from incorrect PSMs. Besides, the described heuristic for solving the optimization problem has to be executed many times to achieve a significant augmentation in sensitivity. RESULTS: Here, we propose a new method, termed MUMAL, for PSM assessment that is based on machine learning techniques. Our method can establish nonlinear decision boundaries, leading to a higher chance to retrieve more true positives. Furthermore, we need few iterations to achieve high sensitivities, strikingly shortening the running time of the whole process. Experiments show that our method achieves a considerably higher number of PSMs compared with standard tools such as MUDE, PeptideProphet, and typical target-decoy approaches. CONCLUSION: Our approach not only enhances the computational performance, and thus the turn around time of MS-based experiments in proteomics, but also improves the information content with benefits of a higher proteome coverage. This improvement, for instance, increases the chance to identify important drug targets or biomarkers for drug development or molecular diagnostics
Development of a first-contact protocol to guide assessment of adult patients in rehabilitation services networks
OBJECTIVE: This paper describes the development of the Protocol for Identification of Problems for Rehabilitation (PLPR), a tool to standardize collection of functional information based on the International Classification of Functioning, Disability and Health (ICF). DEVELOPMENT OF THE PROTOCOL: The PLPR was developed for use during the initial contact with adult patients within a public network of rehabilitation services. Steps to develop the protocol included: survey of the ICF codes most used by clinical professionals; compilation of data from functional instruments; development and pilot testing of a preliminary version in the service settings; discussion with professionals and development of the final version. The final version includes: user identification; social and health information; brief functional description (BFD); summary of the BFD; and PLPR results. Further testing of the final version will be conducted. CONCLUSIONS: The protocol standardizes the first contact between the user and the rehabilitation service. Systematic use of the protocol could also help to create a functional database that would allow comparisons between rehabilitation services and countries over time
Insights on the extraction performance of Alkanediols and Glycerol: ssing Juglans regia L. Leaves as a source of bioactive compounds
Glycerol and alkanediols are being studied as alternative solvents to extract phytochemicals
from plant material, often as hydrogen bond donors in deep eutectic solvents (DESs). Many of those
alcohols are liquid at room temperature, yet studies of their use as extraction solvents are scarce.
In this work, glycerol and a series of alkanediols (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol,
1,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, and 1,2-hexanediol) were studied for the extraction
of phenolic compounds from Juglans regia L. leaves, a rich source of this class of bioactive compounds.
The extraction yield was quantified, and the bioactivity of both extracts and pure solvents was
evaluated by measuring the anti-inflammatory and cytotoxic activities. The solvents showing the best
combined results were 1,2 and 1,3-propanediol, as their extracts presented a high amount of phenolic
compounds, close to the results of ethanol, and similar cytotoxicity against cervical carcinoma cells,
with no impact on non-tumor porcine liver cells in the studied concentration range. On the other hand,
none of the extracts (and solvents) presented anti-inflammatory activity. Overall, the results obtained
in this work contribute to the study of alternative solvents that could potentially be used also as
formulation media, highlighting the importance of walnut leaves as a source of bioactive compounds.This work was developed within the scope of the CIMO-Mountain Research Center UIDB/00690/2020
and CICECO-Aveiro Institute of Materials UIDB/50011/2020 & UIDP/50011/2020 projects, both financed by
national funds through the Portuguese Foundation for Science and Technology (FCT)/MCTES, as well as
POCI-01-0145-FEDER-006984 (LA LSRE-LCM), funded by ERDF, through POCI-COMPETE2020 and FCT.
The authors also thank the national funding from FCT, P.I., through the individual scientific employment
program-contract for L. Barros and R. C. Calhelha and V. Vieira’s grant (SFRH/BD/108487/2015). Support was
also provided by project AllNat—POCI-01-0145-FEDER-030463 (PTDC/EQU-EPQ/30463/2017), funded by FEDER
funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI), and by
national funds through the Foundation for Science and Technology (FCT/MCTES).info:eu-repo/semantics/publishedVersio
Tailloring deep eutectic solvents for the extraction of valuable compounds from natural sources using choline chloride and carboxylic acids mixtures: optimization of the extraction of phenolic compounds from Juglans regia L. leaves
Phenolic compounds are a wide group of plant secondary metabolites with increasing interest due to their antioxidant ability
and marked effects on oxidative processes related to several chronic diseases. Nowadays, they find applications in
pharmaceutical products, functional foods and natural-based cosmetics. Therefore, the extraction and identification of these
valuable compounds from different plants have become a major research area. Nevertheless, conventional solid-liquid
extraction of phenolics usually involves the use of flammable, toxic and volatile organic solvents. Deep eutectic solvents (DES)
are gaining much interest as alternative solvents to extract valuable compounds from natural matrices. DES can be considered
“designer solvents” due to the possibility of combining different HBA (hydrogen bond acceptor) and HBD (hydrogen bond
donor) to obtain solvents with specific properties to the target application. In this study, DES composed of choline chloride (CC)
and different groups of organic acids were prepared, in order to extract phenolic compounds from leaves of Juglans regia L.
(walnut leaves). The initial screening involved monocarboxylic (acetic, propionic, butyric, valeric, lactic and glycolic acids),
dicarboxylic (malonic, glutaric and malic acids), tricarboxylic (citric) and aromatic acids (phenylacetic acid, 3-phenylpropanoic
acid). The initial extraction conditions were: 50 ºC, 60 min extraction time and 20% water content. The main phenolic compounds (neochlorogenic acid, quercetin 3-O-glucoside and quercetin O-pentoside) were quantified by high performance
liquid chromatography coupled to a diode de array detector (HPLC-DAD at 280 and 370 nm). Higher extraction yields were
obtained using CC:butyric acid and CC:3-phenylpropanoic acid. For these systems, the stoichiometric ratio of HBA and HBD as
well as the water content in the DES solutions were further evaluated. Better results were obtained using DES compared to the
conventional water + ethanol mixed solvent. The present work contributes to the valorization of walnut leaves extracts using
alternative solvents that could be tailored for potential applications in the food and pharmaceutical areas.The authors thank the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO
(UID/AGR/00690/2013), L. Barros (SFRH/BPD/107855/2015) and V. Vieira (SFRH/BD/108487/2015) grants. To POCI-01-0145-FEDER-006984 (LA LSRE-LCM),
funded by ERDF, through POCI-COMPETE2020 and FCT. To Xunta de Galicia for financial support for the post-doctoral researcher of M.A. Prieto.info:eu-repo/semantics/publishedVersio
Enhanced extraction of phenolic compounds using choline chloride based deep eutectic solvents from Juglans regia L.
The extraction of phenolic compounds from walnut leaves (Juglans regia L.) was optimized using heat-assisted
extraction and deep eutectic solvents based on choline chloride and carboxylic acids. A preliminary solvent
screening was performed using a selected group of carboxylic acids as hydrogen bond donors, showing that the
highest extraction yield of phenolic compounds was obtained using choline chloride mixtures with butyric or
phenylpropionic acid at a mole ratio 1:2, with 20% of water (w/w). The extraction conditions (time, temperature
and water proportion) were then optimized by an experimental design, assisted by response surface methodology.
To evaluate the response, the three most abundant compounds identified by HPLC (neochlorogenic acid,
quercetin 3-O-glucoside and quercetin O-pentoside) were quantified. Additionally, the solid/liquid ratio effect at
the optimal conditions, in dose-response format, was studied in view of its upscale, not showing any significant
decrease until 140 g/L. The results here presented provide valuable information towards the design of a process
in a pre-industrial form for the extraction of phenolic compounds from J. regia leaves using deep eutectic solvents.The authors thank the Foundation for Science and Technology (FCT,
Portugal) and FEDER under Programme PT2020 for financial support to
CIMO (UID/AGR/00690/2013), V. Vieira (SFRH/BD/108487/2015)
grant and L. Barros contract. To project POCI-01-0145-FEDER-006984 –
Associate Laboratory LSRE-LCM funded by FEDER through
COMPETE2020 – Programa Operacional Competitividade e
Internacionalização (POCI) – and by national funds through FCT –
Fundação para a Ciência e a Tecnologia. To project CICECO‐Aveiro
Institute of Materials POCI‐01‐0145‐FEDER‐007679 (FCT Ref. UID/
CTM/50011/2013), financed by national funds through the FCT/MEC
and when appropriate co‐financed by FEDER under the PT2020
Partnership Agreement. This work is funded by the European Structural
and Investment Funds (FEEI) through POCI, within the scope of Project
POCI nº 030463. To Xunta de Galicia for financial support for the postdoctoral
researcher of M.A. Prieto.info:eu-repo/semantics/publishedVersio
Terpenes solubility in water and their environmental distribution
Terpenes and terpenoids belong to the largest and most diverse class of natural products. Due to the increasing importance of their applications and the emerging perception of their impact on the environment, the available physico-chemical characterization is insufficient. In this work the water solubility of geraniol, linalool, DL-citronellol, thymol, eugenol, carvacrol and p-cymene, in the temperature range from (298.15 to 323.15) K, and at atmospheric pressure, is studied. Due to the low solubility of these compounds a novel technique was adopted for their measurements and validated using the aqueous solubility data for sparingly soluble aromatic compounds. The thermodynamic properties of solution were derived from the experimental data at infinite dilution. It is shown that the solubility of terpenes in water is an endothermic process confirming the existence of UCST phase diagrams, and only for carvacrol and eugenol is entropically driven. The experimental information is shown in a two-dimensional chemical space diagram providing indications to their probable distribution in the environment once released.Thisworkwas developed in the scope of the project CICECO - Aveiro
Institute ofMaterials, POCI-01-0145-FEDER-007679, and Associate Laboratory
LSRE-LCM, POCI-01-0145-FEDER-006984, both funded by
FEDER under the PT2020 Partnership Agreement - Programa
Operacional Competitividade e Internacionalização (POCI) - and by national
funds through FCT - Fundação para a Ciência e a Tecnologia.
M.A.R.M acknowledges FCT for her PhD grant (SFRH/BD/87084/2012).info:eu-repo/semantics/publishedVersio
Propranolol resolution using enantioselective biphasic systems
The commercialization of chiral drugs is an increasing concern in the pharmacological field
since the differences in the pharmacological activities of enantiomers may result in serious
problems in the treatment of diseases using racemates. The resolution of chiral drugs is
important for the development of safer and more active pharmaceuticals. This work aims to
develop an enantioseparation platform for the resolution of propranolol (R/S-PRP) resorting to
esters of tartaric acid and chiral ionic liquids (CILs) as chiral selectors in biphasic systems.
More specifically, the efficiency of enantioselective liquid–liquid extraction (ELLE) systems,
both aqueous and non-aqueous biphasic systems, are here studied, aiming to do a direct
comparison between these two types of systems for the resolution of R/S-PRP. Studies were
carried to evaluate the proper phase forming components of ELLE, R/S-PRP:chiral selector
ratio, the potential of CIL over esters of tartaric acid, and the most suitable alkyl chain length
for the esters of tartaric acid. It was found that the selected organic phase formers of ELLE,
1,2-dichloroethane and ethyl acetate, greatly impact the potential of the enantiorecognition of
the system. The most efficient biphasic system identified was composed of 1,2-dichloroethane-
water, and dipentyl-L-tartrate and boric acid as chiral selectors, with a enantioselectivity of
2.54. This system was further employed for the resolution of R/S-PRP in centrifugal partition
chromatography, to assess its scalability potential, being shown that it was possible to increase
the purity of R-PRP from 59% to 75%.publishe
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