Revisiting the scaling of the specific heat of the three-dimensional random-field Ising model

We revisit the scaling behavior of the specific heat of the three-dimensional random-field Ising model with a Gaussian distribution of the disorder. Exact ground states of the model are obtained using graph-theoretical algorithms for different strengths = 268 3 spins. By numerically differentiating the bond energy with respect to h, a specific-heat-like quantity is obtained whose maximum is found to converge to a constant in the thermodynamic limit. Compared to a previous study following the same approach, we have studied here much larger system sizes with an increased statistical accuracy. We discuss the relevance of our results under the prism of a modified Rushbrooke inequality for the case of a saturating specific heat. Finally, as a byproduct of our analysis, we provide high-accuracy estimates of the critical field hc = 2.279(7) and the critical exponent of the correlation exponent ν = 1.37(1), in excellent agreement to the most recent computations in the literature

Self-delivering nanoemulsions for dual fluorine-19 MRI and fluorescence detection.

Contains fulltext : 71079.pdf (publisher's version ) (Closed access)We report the design, synthesis, and biological testing of highly stable, nontoxic perfluoropolyether (PFPE) nanoemulsions for dual 19F MRI-fluorescence detection. A linear PFPE polymer was covalently conjugated to common fluorescent dyes (FITC, Alexa647 and BODIPy-TR), mixed with pluronic F68 and linear polyethyleneimine (PEI), and emulsified by microfluidization. Prepared nanoemulsions (<200 nm) were readily taken up by both phagocytic and non-phagocytic cells in vitro after a short (approximately 3 h) co-incubation. Following cell administration in vivo, 19F MRI selectively visualizes cell migration. Exemplary in vivo MRI images are presented of T cells labeled with a dual-mode nanoemulsion in a BALB/c mouse. Fluorescence detection enables fluorescent microscopy and FACS analysis of labeled cells, as demonstrated in several immune cell types including Jurkat cells, primary T cells and dendritic cells. The intracellular fluorescence signal is directly proportional to the 19F NMR signal and can be used to calibrate cell loading in vitro

(19)F MRI for quantitative in vivo cell tracking.

Contains fulltext : 89778.pdf (publisher's version ) (Closed access)Cellular therapy, including stem cell transplants and dendritic cell vaccines, is typically monitored for dosage optimization, accurate delivery, and localization using noninvasive imaging, of which magnetic resonance imaging (MRI) is a key modality. (19)F MRI retains the advantages of MRI as an imaging modality, and also allows direct detection of labeled cells for unambiguous identification and quantification, unlike typical metal-based contrast agents. Recent developments in (19)F MRI-based in vivo cell quantification, the existing clinical use of (19)F compounds and current explosive interest in cellular therapeutics have brought (19)F imaging technology closer to clinical application. We review the application of (19)F MRI to cell tracking, discussing intracellular (19)F labels, cell labeling and in vivo quantification, as well as the potential clinical uses of (19)F MRI.1 juli 201

Gene expression analysis of dendritic cells that prevent diabetes in NOD mice: analysis of chemokines and costimulatory molecules.

Contains fulltext : 96948.pdf (publisher's version ) (Closed access)We have demonstrated previously that BM-derived DCs can prevent diabetes development and halt progression of insulitis in NOD mice, the mouse model of type 1 diabetes. The DC population that was most effective in this therapy had a mature phenotype, expressed high levels of costimulatory molecules, and secreted low levels of IL-12p70. The protective DC therapy induced Treg and Th2 cells in vitro and in vivo. Microarray analysis of therapeutic and nontherapeutic DC populations revealed differences in the expression of OX40L, CD200, Ym-1, CCL2, and CCL5, which could play important roles in the observed DC-mediated therapy. The unique pattern of costimulatory molecules and chemokines expressed by the therapeutic DCs was confirmed by flow cytometry and ELISA. Using a novel cell-labeling and (19)F NMR, we observed that the chemokines secreted by the therapeutic DCs altered the migration of diabetogenic Th1 cells in vivo and attracted Th2 cells. These results suggest that the therapeutic function of DCs is mediated by a combination of costimulatory and chemokine properties that results in the attraction of diabetogenic Th1 and the induction of Th2 and/or Treg differentiation.1 september 201

Functional assessment of human dendritic cells labeled for in vivo (19)F magnetic resonance imaging cell tracking.

Item does not contain fulltextBACKGROUND AIMS: Dendritic cells (DC) are increasingly being used as cellular vaccines to treat cancer and infectious diseases. While there have been some promising results in early clinical trials using DC-based vaccines, the inability to visualize non-invasively the location, migration and fate of cells once adoptively transferred into patients is often cited as a limiting factor in the advancement of these therapies. A novel perflouropolyether (PFPE) tracer agent was used to label human DC ex vivo for the purpose of tracking the cells in vivo by (19)F magnetic resonance imaging (MRI). We provide an assessment of this technology and examine its impact on the health and function of the DC. METHODS: Monocyte-derived DC were labeled with PFPE and then assessed. Cell viability was determined by examining cell membrane integrity and mitochondrial lipid content. Immunostaining and flow cytometry were used to measure surface antigen expression of DC maturation markers. Functional tests included bioassays for interleukin (IL)-12p70 production, T-cell stimulatory function and chemotaxis. MRI efficacy was demonstrated by inoculation of PFPE-labeled human DC into NOD-SCID mice. RESULTS: DC were effectively labeled with PFPE without significant impact on cell viability, phenotype or function. The PFPE-labeled DC were clearly detected in vivo by (19)F MRI, with mature DC being shown to migrate selectively towards draining lymph node regions within 18 h. CONCLUSIONS: This study is the first application of PFPE cell labeling and MRI cell tracking using human immunotherapeutic cells. These techniques may have significant potential for tracking therapeutic cells in future clinical trials.1 april 201

209Bi NMR in the heavy-electron system YbBiPt

Bismuth NMR Knight shift and spin lattice relaxation rate 1/T1 data are reported between 35 and 325 K in the low-carrier heavy fermion system YbBiPt. The Knight shift is strongly temperature dependent and negative. Its temperature dependence tracks the bulk susceptibility with a hyperfine coupling constant Ahf = -7.88 kOe/μB. At low temperatures 1/T1 exhibits a dramatic increase, such that the average 4f spin correlation time τf shows a crossover behavior at about 75 K. The rate 1 τf is proportional to temperature above 75 K, consistent with non-interacting 4f local moments which are relaxed via Korringa-type scattering with the conduction electrons. We discuss the behavior below 75 K in terms of crystal-field effects or a strongly temperature dependent contribution from non-zero q regime of the dynamical susceptibility. © 1995

Revisiting the institutions-growth nexus in developing countries : The new evidence

In this paper we revisit the institutions-growth nexus in developing countries including the East Asian region. The region has in the past three decades not only achieved spectacular economic growth, but also experienced one of the worst financial crises, i.e. Asian financial crisis (AFC) in 1997-1998. Utilising the neoclassical growth framework augmented with institutional controls and latest estimation technique in panel data analysis, this study finds evidence of positive institutions effect on growth. Nonetheless, the evidence is limited to security of property rights only with no similar evidence on efficient bureaucracy and strong government. This study also uncovers the channel of the institutional effects on economic growth, i.e. via total factors productivity. This study adds to the literature of East Asian growth, which hitherto, to the best of our knowledge, has seen only two studies, namely Rodrik (1997) 'TFPG controversies, institutions, and economic performance in East Asia' and Campos and Nugent (1999) 'Development performance and the institutions of governance: Evidence from East Asia and Latin America' that document the evidence of institutional importance on economic growth, and these studies are however for the period before the AFC

Universality aspects of the trimodal random-field Ising model

We investigate the critical properties of the d = 3 random-field Ising model with an equal-weight trimodal distribution at zero temperature. By implementing suitable graph-theoretical algorithms, we compute large ensembles of ground states for several values of the disorder strength h and system sizes up to N = 1283. Using a new approach based on the sample-to-sample fluctuations of the order parameter of the system and proper finite-size scaling techniques we estimate the critical disorder strength hc = 2.747(3) and the critical exponents of the correlation length ν = 1.34(6) and order parameter β = 0.016(4). These estimates place the model into the universality class of the corresponding Gaussian random-field Ising model