1,227 research outputs found
Differentiation of equine bone marrow derived mesenchymal stem cells increases the expression of immunogenic genes
Mesenchymal stem cells (MSCs) are a promising treatment for equine musculoskeletal injuries because of their ability to regulate the inflammation and to differentiate into other cell types. Since interest in allogeneic therapy is rising, concerns about MSC immunogenicity need to be addressed. Differentiated MSCs from several species increase their expression of immunogenic molecules and induce alloresponses, but equine MSC immunogenic profile after differentiation has not been reported. Therefore, the aim of this study was to assess the gene expression of immunogenic markers in tri-lineage differentiated equine bone marrow derived MSCs (eBM-MSCs). For this purpose, eBM-MSCs (n = 4) were differentiated into osteoblasts, adipocytes and chondrocytes. Differentiation was confirmed by specific staining and gene expression of lineage-related markers. Subsequently, gene expression of MHC-I, MHC-II, CD40 and CD80 was analyzed in undifferentiated (control) and tri-lineage differentiated eBM-MSCs. Osteogenesis and adipogenesis, but not chondrogenesis, significantly upregulated MHC-I; MHC-II expression significantly increased in the three lineages, while CD40 and CD80 expression did not change. Despite this, MHC-I and MHC-II upregulation after differentiation might lead to increased immunogenicity and risk of allorecognition, either eBM-MSCs differentiate in vivo after administration or they are differentiated prior to administration, with potential negative consequences for effectiveness and safety of allogeneic therapy
Noncommutativity in quantum cosmology and the Hierarchy problem
We study the quantum cosmology of an empty (4+1)-dimensional Kaluza-Klein
cosmology with a negative cosmological constant and a FRW type metric with two
scale factors, one for 4-D universe and the other for one compact extra
dimension. By assuming the noncommutativity in the corresponding
mini-superspace we suggest a solution for the Hierarchy problem, at the level
of Wheeler-DeWitt equation.Comment: 7 pages; Title, abstract and text changed; references added; to
appear in PL
Tetranuclear coordination assemblies based on half-sandwich ruthenium(II) complexes. Non covalent binding to DNA and cytotoxicity.
The reaction of [(cymene)RuCl2]2 with K2Hoxonate (H3oxonic = 4,6-dihydroxy-2-carboxy-1,3,5-triazine acid) in methanol leads to the formation of the dinuclear half-sandwich ruthenium(II) complex [(cymene)2Ru2(\u3bc-Hoxonato)Cl2] (1a). Removal of the chloride ligands of 1a by treatment with AgCF3SO3 yields [(cymene)2Ru2(\u3bc-Hoxonato)(CF3SO3)2] (1b), which, upon posterior reaction with N,N'-linkers (L = 4,4'-bipyridine (4,4'-bpy), 4,7-phenantroline (4,7-phen)), gives rise to the formation of the tetranuclear open boxes [(cymene)4Ru4(\u3bc-Hoxonato)2(\u3bc-N,N'-L)2](CF3SO3)4 (2a, L = 4,4'-bpy; 2b, L = 4,7-phen). These systems have been characterized by 1HNMR, UV-vis, and ESI-MS. The single-crystal structures of the dinuclear precursor 1a and of the clathrate 2b 824,7-phen have been determined. The interaction of these systems with cysteine, mononucleotides, and calf-thymus DNA has been studied by means of 1HNMR, UV-vis, circular dicroism, competitive binding assays, and atomic force microscopy imaging. The results show that the robust tetracationic ruthenium(II) cyclic systems 2a and 2b do not give ligand exchange reactions toward biorelevant ligands. Nevertheless, these systems are able to noncovalently bind to DNA, probably at the surface of the major groove, inducing significant conformational changes in this biomolecule. It is also interesting to note that compounds 2a and 2b, in spite of only giving supramolecular interactions with biomolecules, exhibit antitumor activity, particularly toward the human ovarian cancer cell line A2780cisR, showing acquired resistance to cisplatin, with respective 4.6 and 8.3 microM IC50 values
The helium trimer with soft-core potentials
The helium trimer is studied using two- and three-body soft-core potentials.
Realistic helium-helium potentials present an extremely strong short-range
repulsion and support a single, very shallow, bound state. The description of
systems with more than two helium atoms is difficult due to the very large
cancellation between kinetic and potential energy. We analyze the possibility
of describing the three helium system in the ultracold regime using a gaussian
representation of a widely used realistic potential, the LM2M2 interaction.
However, in order to describe correctly the trimer ground state a three-body
force has to be added to the gaussian interaction. With this potential model
the two bound states of the trimer and the low energy scattering helium-dimer
phase shifts obtained with the LM2M2 potential are well reproduced.Comment: 15 pages, 3 figures, submitted to Few-Body System
Citrate-Stabilized Gold Nanoparticles as High-Performance Electrocatalysts: The Role of Size in the Electroreduction of Oxygen
Fuel cells stand out as among the most promising alternatives for non-sustainable fossil fuel based economy. Efficient electrocatalysts for the oxygen reduction reaction (ORR) are required for the mass application of fuel cells. Citrate-stabilized gold nanoparticles (AuNPs) are proposed as potentialdependent electrocatalysts for the ORR. AuNPs were synthesized by a green, reproducible, and easy scale-up method. After exhaustive characterization, the electrocatalytic activity of the resulting AuNPs was investigated in alkaline media. Static and dynamic electrochemical studies showed a core-size dependent tendency both for their potentials and intensities. For the first time ever, the hysteresis effect in the ORR profile over Au nanoelectrocatalysts is reported herein. In addition, the electrocatalytic efficiency was comparable to those obtained for Au clusters, suggesting the benefits of the citrate stabilizing agent on the electrocatalyst performance of nanomaterials based on noble metals for ORR. These results pave the way for the design of non-coated AuNPs as strong candidates for ORR
Правовий режим як критерій поділу права на галузі
Стаття присвячена проблемам поділу системи права на приватне та публічне. У статті аналізуються наявні наукові теорії розподілу права з використанням різних критеріїв, серед яких автор виокремлює правовий режим, як основа утворення галузей вітчизняного законодавства. Ключові слова: приватне право, публічне право, режим, правовий режим.Статья посвящена проблемам разделения системы права на частное и публичное. В статье анализируются имеющиеся научные теории распределения права с использованием разных критериев, среди которых автор выделяет правовой режим, как основа образования отраслей отечественного законодательства. Ключевые слова: частное право, публичное право, режим, правовой режим.The article is sacred to the problems of division of the system of right on private and public. In the article the present scientific theories of distribution are analysed rights with the use of different criteria, among which an author distinguishes the legal mode, as basis of formation of industries of domestic legislation. Key words: private right, public law, mode, legal mode
Tailoring the ORR and HER electrocatalytic performances of gold nanoparticles through metal–ligand interfaces
The oxygen reduction (ORR) and hydrogen evolution (HER) reactions are the most important cathodic processes involved in fuel cell and water splitting technologies, respectively. The development of bifunctional electrocatalyst materials plays a key role in the rapid advancement of these hydrogen-based renewable energy strategies. This work proposes citrate-stabilized gold nanoparticles (AuNPs) as a bifunctional electrocatalyst for ORR and HER. The capping ligand has a great influence on their resulting electrocatalytic performance. A simple ligand exchange method based on concentration gradients has been optimized. The surface structure of the different ligand-stabilized AuNPs was inferred by lead underpotential deposition (Pb-UPD). Static and dynamic electrochemical studies for both ORR and HER have been performed using different ligand-stabilized AuNPs as electrocatalysts, demonstrating that the citrate ligand confers the best performance. This work suggests that non-doped chemically synthesized AuNPs may be suitable as a bifunctional electrocatalyst in fuel cells and hydrogen production
Illusions of general relativity in Brans-Dicke gravity
Contrary to common belief, the standard tenet of Brans-Dicke theory reducing
to general relativity when omega tends to infinity is false if the trace of the
matter energy-momentum tensor vanishes. The issue is clarified in a new
approach using conformal transformations. The otherwise unaccountable limiting
behavior of Brans-Dicke gravity is easily understood in terms of the conformal
invariance of the theory when the sources of gravity have radiation-like
properties. The rigorous computation of the asymptotic behavior of the
Brans-Dicke scalar field is straightforward in this new approach.Comment: 16 pages, LaTeX, to appear in Physical Review
Comparison of autologous bone marrow and adipose tissue derived mesenchymal stem cells, and platelet rich plasma, for treating surgically induced lesions of the equine superficial digital flexor tendon
Several therapies have been investigated for equine tendinopathies, but satisfactory long term results have not been achieved consistently and a better understanding of the healing mechanism elicited by regenerative therapies is needed. The aim of this study was to assess the separate effects of autologous bone marrow (BM) and adipose tissue (AT) derived mesenchymal stem cells (MSCs), and platelet rich plasma (PRP), for treating lesions induced in the superficial digital flexor tendon (SDFT) of horses. Lesions were created surgically in both SDFTs of the forelimbs of 12 horses and were treated with BM-MSCs (six tendons), AT-MSCs (six tendons) or PRP (six tendons). The remaining six tendons received lactated Ringer''s solution as control. Serial ultrasound assessment was performed prior to treatment and at 2, 6, 10, 20 and 45 weeks post-treatment. At 45 weeks, histopathology and gene expression analyses were performed. At week 6, the ultrasound echogenicity score in tendons treated with BM-MSCs suggested earlier improvement, whilst all treatment groups reached the same level at week 10, which was superior to the control group. Collagen orientation scores on histological examination suggested a better outcome in treated tendons. Gene expression was indicative of better tissue regeneration after all treatments, especially for BM-MSCs, as suggested by upregulation of collagen type I, decorin, tenascin and matrix metalloproteinase III mRNA. Considering all findings, a clear beneficial effect was elicited by all treatments compared with the control group. Although differences between treatments were relatively small, BM-MSCs resulted in a better outcome than PRP and AT-MSCs
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