262 research outputs found
Valorization of hydrolysis lignin from a spruce-based biorefinery by applying -valerolactone treatment
Hydrolysis lignin, i.e., the hydrolysis residue of cellulosic ethanol plants, was extracted with the green solvent γ-valerolactone (GVL). Treatments at 170–210 ◦C were performed with either non-acidified GVL/water mixtures (NA-GVL) or with mixtures containing sulfuric acid (SA-GVL). SA-GVL treatment at 210 ◦C resulted in the highest lignin solubilization (64% (w/w) of initial content), and 76% of the solubilized mass was regenerated by water induced precipitation. Regenerated lignins were characterized through compositional analysis with sulfuric acid, as well as using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), high-performance size-exclusion chromatography (HPSEC), solid-state cross-polarization/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy, 1 H–13C heteronuclear single-quantum coherence NMR (HSQC NMR), and Fourier-transform infrared (FTIR) spectroscopy. The characterization revealed that the main difference between regenerated lignins was their molecular weight. Molecular weight averages increased with treatment temperature, and they were higher and had broader distribution for SA-GVL lignins than for NA-GVL lignins.publishedVersio
Cell assay using a two-photon-excited europium chelate
We report application of two-photon excitation of europium chelates to immunolabeling of epidermal growth factor receptor (EGFR) cell surface proteins on A431 cancer cells. The europium chelates are excited with two photons of infrared light and emit in the visible. Europium chelates are conjugated to antibodies for EGFR. A431 (human epidermoid carcinoma) cells are labeled with this conjugate and imaged using a multiphoton microscope. To minimize signal loss due to the relatively long-lived Eu3+ emission, the multiphoton microscope is used with scanning laser two-photon excitation and non-scanning detection with a CCD. The chelate labels show very little photobleaching (less than 1% during continuous illumination in the microscope for 20 minutes) and low levels of autofluorescence (less than 1% of the signal from labeled cells). The detection limit of the europium label in the cell assay is better than 100 zeptomoles
PERSPECTIVAS DE MANEJO DE CAPOROROCA (Myrsine umbellate MART.) UTILIZANDO ANÁLISE RETROSPECTIVA
A análise retrospectiva é um instrumento para avaliação rápida do potencial de crescimento utilizando-se a periodicidade do incremento em diâmetro, isto é, o crescimento dos anéis anuais. Utilizando-se esta técnica, foi avaliado o desenvolvimento e o crescimento da capororoca (Myrsine umbellata Mart.), espécie nativa da Florestal Ombrofila Mista. O presente estudo foi realizado no Município de General Carneiro PR, em área pertencente às Indústrias Pedro N. Pizzatto. Foi feita a análise de tronco e a medição dos anéis anuais em fatias retiradas nas alturas relativas a 10%, 50% e 75% da altura do ponto de inversão morfológico, bem como também na altura do DAP em quatro árvores, nas quais foram analisados o incremento em diâmetro e altura. Pelos resultados obtidos, pode-se considerar que as árvores analisadas mostraram um crescimento em diâmetro forte no estado inicial, mas seguindo uma tendência de crescimento lento e contínuo a médio prazo, até a idade de 5 anos. Com relação à altura comercial (ponto de inversão morfológico) com 2 a 4 metros, nas árvores analisadas são alcançadas dentro dos primeiros dois anos de vida.ABSTRACT A retrospective analysis is an instrument for the fast evaluation of the potential for growth using the periodical of the increment in diameter, that is, the growth of the annual rings. By applying this technique, it was evaluated the growth and the development of capororoca (Myrsine umbellata Mart.), native species of the mixed ombrofile Forest. This research was accomplished in the municipal area of General Carneiro, in Paraná, an area belonging to the industries of Pedro N. Pizzatto. It was made an analysis of the steam and the measures of the annual rings in parts which were removed from the relative heights of 10%, 50% e 75% to the height of the point of morphological inversion, as well as of the DAP height in four trees, in which were analyzed the increment in diameter and height. By the results obtained, it can be considered that the analyzed trees showed a growth in strong diameter in the initial state, but followed a tendency of a slow and continuous growth in the medium term, up to the age of 5 years old. Concerning the commercial height (morphological inversion point) of 2 to 4 meters, this is achieved within the two first years in the analyzed trees
Magnesium metallic complex coordinated phenolic used for inhibitor of reactive oxygen species (ROS) in biological system
Magnesium metallic complex coordinated phenolic used for inhibitor of reactive oxygen species (ROS) in biological system
Modeling Calcium Dynamics in Human Atria
Abstract Mathematical models of cardiac electrophysiology are an important tool to investigate the underlying mechanisms responsible of arrhythmias. In particular, an important question is the origin of atrial fibrillation (AF). Often, AF initiation is preceded by action potential duration (APD) alternans, i.e., beat to beat oscillations in the APD, that arise at slower rates in patients with persistent AF than in those without AF or with paroxymal AF. Most of these arrhythmias appear as a consequence of malfunctions in calcium dynamics that produce oscillations in intracellular calcium, inducing subsequent APD alternans through electromechanical coupling. The aim of this work is to present a human atrial mathematical model that gives insight into the presence of calcium alternans. For that the model by Nygren et al was modified in order to reproduce calcium alternans at high pacing rhythms, as has been observed in experiments. The model reproduces the nonlinear dependence of gain and fractional SR Ca release upon SR Ca load. At fast pacing rates it presents alternans, due to slow recovery from inactivation of the RyR. Finally, we compare the results from this new model with other human atrial models well established in the literature
Trends in the Management of Non-Vestibular Skull Base and Intracranial Schwannomas
The aim of this review is to analyze the latest trends in the management of nonvestibular skull base and intracranial schwannomas in order to optimize tumor control and quality of life. Non-vestibular cranial nerve schwannomas are rare lesions, representing 5-10% of cranial nerve schwannomas. Management decisions should be individualized depending on tumor size, location and associated functional deficits. Generally, large sized schwannomas exerting significant mass effect with increased intracranial pressure are treated surgically. In some cases, even after optimal skull base resection, it is not possible to achieve a gross total resection because tumor location and extent and/or to reduce morbidity. Thus, subtotal resection followed by stereotactic radiosurgery or fractioned radiotherapy offers an alternative approach. In certain cases, stereotactic radiosurgery or radiotherapy alone achieves good tumor control rates and less morbidity to gross total resection. Finally, given the slow growth rate of most of these tumors, observation with periodic radiographic follow-up approach is also a reasonable alternative for small tumors with few, if any, symptoms.Peer reviewe
Rapid adaptive radiation of Darwin's finches depends on ancestral genetic modules
Recent adaptive radiations are models for investigating mechanisms contributing to the evolution of biodiversity. An unresolved question is the relative importance of new mutations, ancestral variants, and introgressive hybridization for phenotypic evolution and speciation. Here, we address this issue using Darwin's finches and investigate the genomic architecture underlying their phenotypic diversity. Admixture mapping for beak and body size in the small, medium, and large ground finches revealed 28 loci showing strong genetic differentiation. These loci represent ancestral haplotype blocks with origins predating speciation events during the Darwin's finch radiation. Genes expressed in the developing beak are overrepresented in these genomic regions. Ancestral haplotypes constitute genetic modules for selection and act as key determinants of the unusual phenotypic diversity of Darwin's finches. Such ancestral haplotype blocks can be critical for how species adapt to environmental variability and change
International multicentre observational study to evaluate the association between perioperative red blood cell transfusions and 1-year mortality after major cancer surgery (ARCA-1) : Study design, statistical analysis plan and study protocol
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.Peer reviewedPublisher PD
The prelude to industrial whaling:Identifying the targets of ancient European whaling using zooarchaeology and collagen mass-peptide fingerprinting
Taxonomic identification of whale bones found during archaeological excavations is problematic due to their typically fragmented state. This difficulty limits understanding of both the past spatio-temporal distributions of whale populations and of possible early whaling activities. To overcome this challenge, we performed zooarchaeology by mass spectrometry on an unprecedented 719 archaeological and palaeontological specimens of probable whale bone from Atlantic European contexts, predominantly dating from ca 3500 BCE to the eighteenth century CE. The results show high numbers of Balaenidae (many probably North Atlantic right whale (Eubalaena glacialis)) and grey whale (Eschrichtius robustus) specimens, two taxa no longer present in the eastern North Atlantic. This discovery matches expectations regarding the past utilization of North Atlantic right whales, but was unanticipated for grey whales, which have hitherto rarely been identified in the European zooarchaeological record. Many of these specimens derive from contexts associated with mediaeval cultures frequently linked to whaling: the Basques, northern Spaniards, Normans, Flemish, Frisians, Anglo-Saxons and Scandinavians. This association raises the likelihood that early whaling impacted these taxa, contributing to their extirpation and extinction. Much lower numbers of other large cetacean taxa were identified, suggesting that what are now the most depleted whales were once those most frequently used.</p
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