1,206 research outputs found
Neuroanastomosis of orthotopically transplanted palmaris longus muscles
Palmaris longus (PML) muscles of rhesus monkeys were transplanted, with or without anastomosis of the median nerve, to the nerve stump of the autograft. Because PML autografts revascularize spontaneously, vascular anastomoses were not performed. Muscle fibers regenerated in all autografts with neuroanastomosis, but in only three of eight autografts without neuroanastomosis. Five autografts without neuroanastomosis were replaced by noncontractile connective tissue. Growth and differentiation of muscle fibers into three fiber types and development of capillarity were analyzed histochemically, and succinate oxidase activity of whole-muscle homogenates was determined. None of these measures reached values for control PML muscles within 100 days of transplantation. In comparison to control muscles, autografts had slower times to peak tension and less absolute tension, but similar tension per square centimeter of muscle fiber cross-sectional area. Monkey PML autografts with neuroanastomosis were similar in structure and function to cat extensor digitorum longus autografts that had not had neuroanastomosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50127/1/880020107_ftp.pd
Lack of ‘acid reversal’ of myofibrillar adenosine triphosphatase in masticatory muscle fibres of rhesus monkeys
Myofibrillar adenosine triphosphatase (ATPase) activity was demonstrated in sections of masseter and temporalis muscles and of selected limb muscles of adult rhesus monkeys. Incubations were performed either with no pre-treatment or after prior incubation in alkaline media (pH 10.2–10.4) or acidic media (pH 3.8–4.6). Without pre-treatment, fibres having high or low ATPase activity were observed in limb and masticatory muscles. Following alkaline pre-incubation the difference between high and low ATPase of limb muscle fibres is accentuated, whereas pre-incubation in acidic media (pH 4.3) results in inhibition of high and potentiation of low ATPase activities (‘acid reversal’). While pre-incubation of masticatory muscle sections at pH 10.2 accentuates differences in ATPase activity, pre-incubation at pH 10.4 abolishes ATPase activity. In contrast, masticatory muscle fibres showed no reversal of ATPase activity following acidic pre-incubation (pH 4.3). Pre-incubation at pH 3.8 abolished the ATPase activity of both limb and masticatory muscle fibres. The biochemical basis for the differences in ATPase histochemistry between masticatory and limb muscles is not known.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42847/1/10735_2005_Article_BF01024551.pd
Representations of U(1,q) and Constructive Quaternion Tensor Products
The representation theory of the group U(1,q) is discussed in detail because
of its possible application in a quaternion version of the Salam-Weinberg
theory.
As a consequence, from purely group theoretical arguments we demonstrate that
the eigenvalues must be right-eigenvalues and that the only consistent scalar
products are the complex ones. We also define an explicit quaternion tensor
product which leads to a set of additional group representations for integer
``spin''.Comment: 28 pages, Latex, Dipartimento di Fisica, Universita di Lecce
INFN-Sezione di Lecc
D4.6 Report on the results of cycle 3 demonstrators:Aggregates internal deliverables ID4.12, ID4.13, ID4.14, ID4.15, ID4.16
Hernández-Leo, D., Sligte, H., Glahn, C., Krekels, B., Keuls, C., Louys, A., Stefanov, K., Perez, M., Chacón, J., Santos, P., Mazzetti, A., Herder, E., Maxwell, K., Kiercheben, J., Griffiths, D., & Kluijfhout, E. (2009). D4.6 - Report on the results of cycle 3 demonstrators. Aggregates internal deliverables ID4.12, ID4.13, ID4.14, ID4.15, ID4.16. TENCompetence.This document includes the evaluation results of the Cycle 3 real-life evaluation activities. A cross-analysis of the results is compiled in order to present the impact indicators of the project in terms of outreach, learning benefits, organizational implications, and business opportunities identified in these experiences. The implementations and eight business/market-relevant demonstrators conducted in collaboration with external "adopter organizations" from different countries in Europe. These external organizations are Associated Partners or different units within the partners'organization. The revised pilots and the demonstrators test the tooling achieved along DIP-3. Both pilots and business demonstrators show to provide benefits to socially- and industrially-relevant scenarios. Areas of proven special impact include adult competence developmentfor social inclusion, provision of learning paths to support competence development of distributed professionals, informal competence development, human resources personal competence development, and sharing of competence profiles between organizations to support the mobility of their professionals.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org
More is the Same; Phase Transitions and Mean Field Theories
This paper looks at the early theory of phase transitions. It considers a
group of related concepts derived from condensed matter and statistical
physics. The key technical ideas here go under the names of "singularity",
"order parameter", "mean field theory", and "variational method".
In a less technical vein, the question here is how can matter, ordinary
matter, support a diversity of forms. We see this diversity each time we
observe ice in contact with liquid water or see water vapor, "steam", come up
from a pot of heated water. Different phases can be qualitatively different in
that walking on ice is well within human capacity, but walking on liquid water
is proverbially forbidden to ordinary humans. These differences have been
apparent to humankind for millennia, but only brought within the domain of
scientific understanding since the 1880s.
A phase transition is a change from one behavior to another. A first order
phase transition involves a discontinuous jump in a some statistical variable
of the system. The discontinuous property is called the order parameter. Each
phase transitions has its own order parameter that range over a tremendous
variety of physical properties. These properties include the density of a
liquid gas transition, the magnetization in a ferromagnet, the size of a
connected cluster in a percolation transition, and a condensate wave function
in a superfluid or superconductor. A continuous transition occurs when that
jump approaches zero. This note is about statistical mechanics and the
development of mean field theory as a basis for a partial understanding of this
phenomenon.Comment: 25 pages, 6 figure
Roles of Coactivators in Hypoxic Induction of the Erythropoietin Gene
Hypoxia-inducible expression of the erythropoietin (EPO) gene is mediated principally by hypoxia-inducible factor 2alpha (HIF-2alpha) in Hep3B cells under physiologic conditions. How/whether p300/CBP and the members of p160 coactivator family potentiate hypoxic induction of endogenous EPO and other HIF-2alpha and hypoxia-inducible factor 1alpha (HIF-1alpha) target genes remains unclear.We demonstrate, using chromatin immunoprecipitation (ChIP) analysis, that the histone acetyl transferase (HAT) coactivators p300, SRC-1 and SRC-3 are recruited to the 3' enhancer of the EPO gene upon hypoxic stimulation, and that each associates with the enhancer in a periodic fashion. Hypoxia induced acetylation of the EPO gene 5' promoter at histone 4 and lysine 23 of histone 3. Knocking down SRC-3, but not SRC-1 or SRC-2, using short interfering RNAs (siRNAs), reduced EPO transcriptional activity. Knocking down p300 resulted in dramatic down-regulation of hypoxic stimulation of EPO gene transcription, negated recruitment of RNA polymerase II to the gene's promoter, and eliminated hypoxia-stimulated acetylation at the promoter and recruitments of SRC-1 and SRC-3 to the enhancer. The inhibitory effects of knocking down p300 and the chromatin remodeling coactivator, Brm/Brg-1, on EPO transcription were additive, suggesting that p300 and Brm/Brg-1 act independently. p300 was also required for hypoxia induced transcription of the HIF-1alpha target gene, VEGF, but was dispensable for induction of two other HIF-1alpha target genes, PGK and LDHA. Knocking down CBP, a homolog of p300, augmented hypoxic induction of VEGF, LDHA and PGK. Different HIF target genes also exhibited different requirements for members of the p160 coactivator family.p300 plays a central coactivator role in hypoxic induction of EPO. The coactivators exhibit different specificities for different HIF target genes and each can behave differently in transcriptional regulation of different target genes mediated by the same transcription factor
Association between the choice of the conditioning regimen and outcomes of allogeneic hematopoietic cell transplantation for myelofibrosis
Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative treatment for myelofibrosis. However, the optimal conditioning regimen either with reduced intensity conditioning (RIC) or myeloablative conditioning (MAC) is not well known. Using the Center for International Blood and Marrow Transplant Research database, we identified adults aged ≥18 years with myelofibrosis undergoing allo-HCT between 2008-2019 and analyzed the outcomes separately in the RIC and MAC cohorts based on the conditioning regimens used. Among 872 eligible patients, 493 underwent allo-HCT using RIC (Fludarabine/busulfan=166, Fludarabine/melphalan=327) and 379 using MAC (Fludarabine/busulfan=247, Busulfan/cyclophosphamide=132). In multivariable analysis with RIC, Fludarabine/melphalan was associated with inferior overall survival (HR 1.80, 95% CI 1.15-2.81, p=0.009), higher early non-relapse mortality (HR 1.81, 95% CI 1.12-2.91, p=0.01) and higher acute graft versus host disease (GVHD) (grade II-IV- HR 1.45, 95% CI 1.03-2.03, p=0.03; grade III-IV HR 2.21, 95%CI 1.28-3.83, p=0.004) compared to Fludarabine/busulfan. In the MAC setting, Busulfan/cyclophosphamide was associated with a higher acute GVHD (grade II-IV HR 2.33, 95% CI 1.67-3.25, p\u3c0.001; grade III-IV HR 2.31, 95% CI 1.52-3.52, p\u3c0.001) and inferior GVHD-free relapse-free survival (GRFS) (HR 1.94, 95% CI 1.49-2.53, p\u3c0.001) as compared to Fludarabine/busulfan. Hence, our study suggests that Fludarabine/busulfan is associated with better outcomes in RIC (better overall survival, lower early non-relapse mortality, lower acute GVHD) and MAC (lower acute GVHD and better GRFS) in myelofibrosis
- …