64 research outputs found
Liquid-gas Phase Transition in Strange Hadronic Matter with Weak Y-Y Interaction
The liquid-gas phase transition in strange hadronic matter is reexamined by
using the new parameters about the interaction deduced from
recent observation of double hypernucleus. The
extended Furnstahl-Serot-Tang model with nucleons and hyperons is utilized. The
binodal surface, the limit pressure, the entropy, the specific heat capacity
and the Caloric curves are addressed. We find that the liquid-gas phase
transition can occur more easily in strange hadronic matter with weak Y-Y
interaction than that of the strong Y-Y interaction.Comment: 10 pages, 7 figure
Delivering hydrophilic and hydrophobic chemotherapeutics simultaneously by magnetic mesoporous silica nanoparticles to inhibit cancer cells
Using nanoparticles to deliver chemotherapeutics offers new opportunities for cancer therapy, but challenges still remain when they are used for the delivery of multiple drugs, especially for the synchronous delivery of hydrophilic and hydrophobic drugs in combination therapies. In this paper, we developed an approach to deliver hydrophilicâhydrophobic anticancer drug pairs by employing magnetic mesoporous silica nanoparticles (MMSNs). We prepared 50 nm-sized MMSNs with uniform pore size and evaluated their capability for the loading of two combinations of chemotherapeutics, namely doxorubicinâpaclitaxel and doxorubicinârapamycin, by means of sequential adsorption from the aqueous solution of doxorubicin and nonaqueous solutions of paclitaxel or rapamycin. Experimental results showed that the present strategy successfully realized the co-loading of hydrophilic and hydrophobic drugs with high-loading content and widely tunable ratio range. We elaborate on the theory behind the molecular interaction between the silica hydroxyl groups and drug molecules, which underlie the controllable loading, and the subsequent release of the drug pairs. Then we demonstrate that the multidrug-loaded MMSNs could be easily internalized by A549 human pulmonary adenocarcinoma cells, and produce enhanced tumor cell apoptosis and growth inhibition as compared to single-drug loaded MMSNs. Our study thus realized simultaneous and dose-tunable delivery of hydrophilic and hydrophobic drugs, which were endowed with improved anticancer efficacy. This strategy could be readily extended to other chemotherapeutic combinations and might have clinically translatable significance
Engineering Scheffersomyces segobiensis for palmitoleic acidârich lipid production
Palmitoleic acid (POA; C16:1) is an essential high- value Ï- 7- conjugated fatty acid with beneficial bioactivities and potential applications in the nu-traceutical and pharmaceutical industries. Previously, the oleaginous yeast Scheffersomyces segobiensis DSM27193 has been identified as a promis-ing production host as an alternative for POA extraction from plant or animal sources. Here, the POA-producing capacity of this host was further expanded by optimizing the fermentation process and molecular strain engineering. Specifically, a dual fermentation strategy (O-S dynamic regulation strategy) focused on the substrate and dissolved oxygen concentration was designed to eliminate ethanol and pyruvate accumulation during fermentation. Key genes influencing POA production, such as jen, dgat, ole were identified on the transcriptional level and were subsequently over-expressed. Furthermore, the phosphoketolase (Xpk)/phosphotransacetylase (Pta) pathway was intro-duced to improve the yield of the precursor acetyl-CoA from glucose. The resulting cell factory SS-12 produced 7.3 g/L of POA, corresponding to an 11-fold increase compared to the wild type, presenting the highest POA titre reported using oleaginous yeast to date. An economic evaluation based on the raw materials, utilities and facility-dependent costs showed that microbial POA production using S. segobiensis can supersede the current extraction method from plant oil and marine fish. This study reports the construction of a promising cell factory and an effective microbial fermentation strategy for commercial POA production
Ectopic tissue engineered ligament with silk collagen scaffold for ACL regeneration: A preliminary study
Anterior cruciate ligament (ACL) reconstruction remains a formidable clinical challenge because of the lack of vascularization and adequate cell numbers in the joint cavity. In this study, we developed a novel strategy to mimic the early stage of repair in vivo, which recapitulated extra-articular inflammatory response to facilitate the early ingrowth of blood vessels and cells. A vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was developed and then transferred to reconstruct the ACL in rabbits without interruption of perfusion. At 2 weeks after ACL reconstruction, more well-perfused cells and vessels were found in the regenerated ACL with ETEL, which decreased dramatically at the 4 and 12 week time points with collagen deposition and maturation. ACL treated with ETEL exhibited more mature ligament structure and enhanced ligament-bone healing post-reconstructive surgery at 4 and 12 weeks, as compared with the control group. In addition, the ETEL group was demonstrated to have higher modulus and stiffness than the control group significantly at 12 weeks post-reconstructive surgery. In conclusion, our results demonstrated that the ETEL can provide sufficient vascularity and cellularity during the early stages of healing, and subsequently promote ACL regeneration and ligament-bone healing, suggesting its clinic use as a promising therapeutic modality. Statement of Significance Early inflammatory cell infiltration, tissue and vessels ingrowth were significantly higher in the extra articular implanted scaffolds than theses in the joint cavity. By mimicking the early stages of wound repair, which provided extra-articular inflammatory stimulation to facilitate the early ingrowth of blood vessels and cells, a vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was constructed by subcutaneous implantation for 2 weeks. The fully vascularized TE ligament was then transferred to rebuild ACL without blood perfusion interruption, and was demonstrated to exhibit improved ACL regeneration, bone tunnel healing and mechanical properties. (C) 2017 Published by Elsevier Ltd on behalf of Acta Materialia Inc
Clean and Selective Oxidation of Alcohols Catalyzed by Ion-supported TEMPO
Abstract-Three different types of ion-supported TEMPO catalysts are synthesized and their catalytic activity in the chemoselective oxidation of alcohols is investigated. These new catalysts show high catalytic activity in water and can be reused for the next run by extraction of products. Recycling experiments exhibit that ion-supported TEMPO can be reused up to five times without loss of catalytic activity. This system offers a very clean, convenient, environmentally benign method for the selective oxidation of alcohols.
The ridge as a shadowing effect in hydrodynamics.
The aim of this work is to clarify the origin of the inplane/outofplane effect, in the twoparticle
correlation function, computed with the NexSPheRIO code, in Au + Au collisions at 200 AGeV. We show
that such an effect can be understood in terms of the shadowing effect caused by a peripheral highenergy
density tube
The Underestimated Halogen Bonds Forming with Protein Side Chains in Drug Discovery and Design
Halogen bonds (XBs) have been attracting
increasing attention in
biological systems, especially in drug discovery and design, for their
advantages of both improving drugâtarget binding affinity and
tuning ADME/T properties. After a comprehensive literature survey
in drug discovery and design, we found that most of the studies on
XBs between ligands and proteins have focused on the protein backbone.
Meanwhile, we also noticed that the proportion of side-chain XBs to
overall XBs decreases as structural resolution becomes lower and lower.
We postulated that protein side chains are more flexible in comparison
with backbone structures, leading to more unclear electron density
and lower resolution of the side chains. As the classic force field
used to refine protein structures from diffraction data cannot handle
XBs correctly, some of the interactions are lost during the refinement.
On the contrary, there is no change in the corresponding ratio of
hydrogen bonds (HBs) during structural resolution because HBs can
be handled well with the classic force field. Further analysis revealed
that Thr and Gln account for a large part of the decreasing XB trend,
which could be partly attributed to the misidentified N, C, or O atoms.
In addition, the lost XBs might be recovered after the atoms are reassigned,
e.g., by flipping Thr side chains. In summary, formation of XBs with
protein side chains is underestimated, and more attention should be
paid to the potential formation of XBs between organohalogens and
protein side chains during X-ray crystallography studies
Deformed even-even nuclei in a quark-meson coupling model with tensor coupling.
In this work, a new quark-meson coupling model is employed to study the ground-state properties
of axially deformed even-even nuclei. Two essential ingredients, namely, density dependence of quark mass
and tensor coupling, play important roles in our approach. In particular, it is the first time that the
deformed quark-meson coupling calculation with tensor coupling is applied to study the properties of
finite nuclei. The present work involves a systematical study of nuclei ranging from Z = 50 to Z = 82.
The ground-state binding energies, quadrupole deformations, shape coexistence, two-neutron separation
energies and the root-mean-square charge radii are calculated and compared with the experimental data.
It is shown that the ground-state properties of the deformed nuclei are reasonably well reproduced by a
model based on the sub-hadronic degrees of freedom
Further results on peripheral-tube model for ridge correlation.
Peripheral one-tube model has shown to be a nice tool for dynamically
understanding several aspects of ridge structures in long-range two-particle
correlations, observed experimentally and obtained also in our model calculations
using NexSPheRIO code. Here, we study an extension of the model,
to initial configurations with several peripheral tubes distributed randomly
in azimuth. We show that the two-particle correlation is almost independent
of the number of tubes, although the flow distribution becomes indeed
strongly event dependent. In our picture, the ridge structures are causally
connected not only in the longitudinal direction but also in azimuth
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