306 research outputs found
Fructo-oligosaccharides separation and purification by simulated moving bed chromatography
The interest on oligosaccharides such as fructo-oligosaccharides (FOS) has strongly increased in recent years for food and pharmaceutical applications, mainly due to their improved technological and functional properties. FOS can be produced by fermentative processes from sucrose, and can be found in mixture with other mono- and di-saccharides and salts, at the end of the process [1]. Unlike FOS, the small saccharides (SGF), namely fructose, glucose and sucrose in the mixture, are known to be cariogenic, caloric and do not present prebiotic activity. The purification of FOS from the other sugars can represent and important increment on the economic value of the final product, which can be further used in diabetic and dietetic food [2]. Different strategies have been developed for this purpose, including microbial treatment [3], ultra and nano-filtration, activated charcoal systems [4], or ion-exchange chromatography [5]. Ion exchange resins may be then used in batch or continuous chromatographic processes, as Simulated Moving Bed (SMB) chromatography, to purify sugars.
A screening of different commercial resins was previously done in order to select the most suitable to separate the oligosaccharides [5]. The resin Diaion 535Ca showed an increased recovery yield and purity of FOS (92 and 90%, respectively). In the present work, the separation process was implemented in the SMB, using the selected resin, namely. Equilibrium adsorption isotherms were determined by the Retention Time Method (RTM), for each single sugar. The resin was afterwards packed in eight SMB columns, and tested in the pilot plant. Different operation parameters, including switching time, extra time, internal flow-rates and operating pump flow-rates for feed, raffinate, desorbent, eluent and recycling streams, were tested in the plant.
The separation of fructose from glucose and FOS from the SGF was evaluated. Firstly, the separation of a binary sugar mixture of fructose/sucrose (~ 50/50%) was performed followed by the separation of FOS from a fermentative broth. Fructose was purified from 53 to 76% and sucrose from 47 to 77%. FOS and SGF were purified from 50 to 67%. The implementation of UV detectors between the SMB columns allowed following the sugar concentration profile online during the separation process. The accurate selection of the operating parameters was made using the concentration signal obtained and showed to be a crucial step for an improved separation
Trypsin purification using magnetic azocasein composite
This contribution presents an inexpensive, simple and fast procedure to purify trypsin from fish viscera based on affinity binding onto magnetic particles of azocasein composite (MAzo). This casein derivative, nonspecific protease substrate, was magnetized by co-precipitation of Fe+2 and Fe+3 ions. Intestines of fish Nile tilapia (Oreochromis niloticus) were homogenized in 0.01 M Tris-HCl buffer, pH 8.0 (one gram of tissue/ml). Afterwards, the homogenate was partially purified with ammonium sulfate (20-40% of saturation), dialyzed and then incubated with MAzo. The adsorbed proteins were firstly extensively washed with 0.01 M Tris-HCl buffer, pH 8.0, and subsequently with 3 M NaCl by collecting the magnetic azocasein composite under a magnetic field. The fractions collected by these washings were used for protein and enzyme activity determinations as well as electrophoresis. The specific activity of the protein collected with 3 M NaCl (41.82 unit/mg) showed to be 220 times higher than that found for the crude extract (0.19 unit/mg). The SDS-PAGE showed that the size of the purified protein was approximately 24 kDa, agreeing with the previously reported for the Nile tilapia trypsin molecular weight. This procedure presents the advantages of magnetic azocasein compostite reuse and can be applied for trypsin purification from other sources
Professional situation of prosthetics and orthotics recent graduates in ESTeSL 2004/2005 to 2012/2013: a sociographic portrait
Introduction – Nowadays the high unemployment rate and the emigration of young graduated population is the reason why this population has been insecure about their career and professional future in their home country. By some way the existence of a reflexive analysis about their actual professional situation could clarify the future for students and recently-graduated in prosthetics and orthotics area. Objectives – Quantifying the professional situation of the graduated population in prosthetics and orthotics on Escola Superior de Tecnologia da Saúde de Lisboa (ESTeSL) and also create a reflection tool about future professional perspectives. Methodology – Application of a questionnaire through the platform LimeSurvey® to the universe of prosthetists and orthotists graduates in ESTeSL and characterize by the quantitative data. Results/Discussion – The majority of the graduates are young and females. 78.3% of the inquired are working on the prosthetics and orthotics area and the unemployment rate is 8.7%. It’s notice a geographical mobility to the district of Lisbon to study and to work. Conclusion – The unemployment rate in prosthetics and orthotics graduates is lower than the national average. In opposition with another graduated health groups, the National Health System is a minor employer of these population. It was noticed a desertification of the big urban centres, in what concerns to the first job and actual jo
Ghrelin increases intake of rewarding food in rodents
We investigated whether ghrelin action at the level of the ventral tegmental area (VTA), a key node in the mesolimbic reward system, is important for the rewarding and motivational aspects of the consumption of rewarding/palatable food. Mice with a disrupted gene encoding the ghrelin receptor (GHS-R1A) and rats treated peripherally with a GHS-R1A antagonist both show suppressed intake of rewarding food in a free choice (chow/rewarding food) paradigm. Moreover, accumbal dopamine release induced by rewarding food was absent in GHS-R1A knockout mice. Acute bilateral intra-VTA administration of ghrelin increased 1-hour consumption of rewarding food but not standard chow. In comparison with sham rats, VTA-lesioned rats had normal intracerebroventricular ghrelin-induced chow intake, although both intake of and time spent exploring rewarding food was decreased. Finally, the ability of rewarding food to condition a place preference was suppressed by the GHS-R1A antagonist in rats. Our data support the hypothesis that central ghrelin signaling at the level of the VTA is important for the incentive value of rewarding food
Preclinical pharmacokinetics and biodistribution of anticancer dinuclear Palladium(II)-Spermine Complex (Pd2Spm) in mice
Palladium-based compounds are regarded as potential analogs to platinum anticancer drugs with improved properties. The present study assessed the pharmacokinetics and biodistribution of a dinuclear palladium(II)-spermine chelate (Pd2Spm), which has previously been shown to possess promising in vitro activity against several therapy-resistant cancers. Using inductively coupled plasma-mass spectrometry, the kinetic profiles of palladium/platinum in serum, serum ultrafiltrate and tissues (kidney, liver, brain, heart, lungs, ovaries, adipose tissue and mammary glands) were studied in healthy female Balb/c mice after a single intraperitoneal bolus injection of Pd2Spm (3 mg/kg bw) or cisplatin (3.5 mg/kg bw) between 0.5 and 48 h post-injection. Palladium in serum exhibited biphasic kinetics with a terminal half-life of 20.7 h, while the free palladium in serum ultrafiltrate showed a higher terminal half-life than platinum (35.5 versus 31.5 h). Palladium was distributed throughout most of the tissues except for the brain, with the highest values in the kidney, followed by the liver, lungs, ovaries, adipose tissue and mammary glands. The in vitro cellular accumulation was also evaluated in breast cancer cells, evidencing a passive diffusion as a mechanism of Pd2Spm’s cellular entry. This study reports, for the first time, the favorable pharmacokinetics and biodistribution of Pd2Spm, which may become a promising pharmacological agent for cancer treatmentinfo:eu-repo/semantics/publishedVersio
Formation and Evolution of Supermassive Black Holes
The correlation between the mass of supermassive black holes in galaxy nuclei
and the mass of the galaxy spheroids or bulges (or more precisely their central
velocity dispersion), suggests a common formation scenario for galaxies and
their central black holes. The growth of bulges and black holes can commonly
proceed through external gas accretion or hierarchical mergers, and are both
related to starbursts. Internal dynamical processes control and regulate the
rate of mass accretion. Self-regulation and feedback are the key of the
correlation. It is possible that the growth of one component, either BH or
bulge, takes over, breaking the correlation, as in Narrow Line Seyfert 1
objects. The formation of supermassive black holes can begin early in the
universe, from the collapse of Population III, and then through gas accretion.
The active black holes can then play a significant role in the re-ionization of
the universe. The nuclear activity is now frequently invoked as a feedback to
star formation in galaxies, and even more spectacularly in cooling flows. The
growth of SMBH is certainly there self-regulated. SMBHs perturb their local
environment, and the mergers of binary SMBHs help to heat and destroy central
stellar cusps. The interpretation of the X-ray background yields important
constraints on the history of AGN activity and obscuration, and the census of
AGN at low and at high redshifts reveals the downsizing effect, already
observed for star formation. History appears quite different for bright QSO and
low-luminosity AGN: the first grow rapidly at high z, and their number density
decreases then sharply, while the density of low-luminosity objects peaks more
recently, and then decreases smoothly.Comment: 31 pages, 13 figures, review paper for Astrophysics Update
From The Perspective Of Oil Painting Analyses The Painting State
绘画状态是古今中外优秀的艺术家所具备的普遍状态,纵观中外美术史进程上艺术家与状态的关系,可以看出绘画的状态有两层内涵,一是绘画本体作为一种状态而表现在艺术家身上,是生活与绘画不可分割的状态,即绘画的精神状态。二是指绘画语言的状态,即艺术家的绘画语言在画面上所呈现的状态。本文重点分别从绘画的精神状态分析当代中国画家刘小东和戴士和的性格、作画状态、文化立场、时代背景等,从绘画的语言状态分析了两位画家画面的结构、造型、色彩的构成、以及笔触肌理等等,总结出绘画状态的获得必须来源于生活和真实的情感表达,绘画的语言状态必须来源于孜孜不倦的练习与研究。最后结合自己的创作进一步强调绘画状态的重要性。Drawing state is the common state for all outstanding artists at all times and in all countries. There are two layers of painting state, as we can see from the relationship between the artist and the state in Chinese and foreign art's historical process. One of them is painting spirit state. it is the noumenon of painting, as it is a status and performance in the artist's life and painting,i...学位:文学硕士院系专业:艺术学院_美术学学号:1862011115342
The Herschel Virgo Cluster Survey: VI. The far-infrared view of M87
The origin of the far-infrared emission from the nearby radio galaxy M87
remains a matter of debate. Some studies find evidence of a far-infrared excess
due to thermal dust emission, whereas others propose that the far-infrared
emission can be explained by synchrotron emission without the need for an
additional dust emission component. We present Herschel PACS and SPIRE
observations of M87, taken as part of the science demonstration phase
observations of the Herschel Virgo Cluster Survey. We compare these data with a
synchrotron model based on mid-infrared, far-infrared, submm and radio data
from the literature to investigate the origin of the far-infrared emission.
Both the integrated SED and the Herschel surface brightness maps are adequately
explained by synchrotron emission. At odds with previous claims, we find no
evidence of a diffuse dust component in M87, which is not unexpected in the
harsh X-ray environment of this radio galaxy sitting at the core of the Virgo
Cluster.Comment: Letter accepted for publication in A&A (Herschel special issue
Encapsulation of Nanostructures in a Dielectric Matrix Providing Optical Enhancement in Ultrathin Solar Cells
The incorporation of nanostructures in optoelectronic devices for enhancing their
optical performance is widely studied. However, several problems related to the
processing complexity and the low performance of the nanostructures have
hindered such actions in real-life devices. Herein, a novel way of introducing gold
nanoparticles in a solar cell structure is proposed in which the nanostructures are
encapsulated with a dielectric layer, shielding them from high temperatures and
harsh growth processing conditions of the remaining device. Through optical
simulations, an enhancement of the effective optical path length of approximately
four times the nominal thickness of the absorber layer is verified with the new
architecture. Furthermore, the proposed concept in a Cu(In,Ga)Se2 solar cell
device is demonstrated, where the short-circuit current density is increased by
17.4%. The novel structure presented in this work is achieved by combining a
bottom-up chemical approach of depositing the nanostructures with a top-down
photolithographic process, which allows for an electrical contact.This work was funded in part by the Fundação para a Ciência e a Tecnologia
(FCT) under Grants IF/00133/2015, PD/BD/142780/2018 and SFRH/BD/
146776/2019. The authors also want to acknowledge the European Union’s
Horizon 2020 Research and Innovation Programme through the ARCIGS-M
project under Grant 720887, the Special Research Fund (BOF) of Hasselt
University, the FCT through the project NovaCell (PTDC/CTM-CTM/28075/
2017), and InovSolarCells (PTDC/FISMAC/29696/2017) co-funded by FCT
and the ERDF through COMPETE2020. The authors also want to acknowledge Sandra Maya for the production of images used in this work.info:eu-repo/semantics/publishedVersio
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