204 research outputs found
Functional Maps Representation on Product Manifolds
We consider the tasks of representing, analyzing and manipulating maps
between shapes. We model maps as densities over the product manifold of the
input shapes; these densities can be treated as scalar functions and therefore
are manipulable using the language of signal processing on manifolds. Being a
manifold itself, the product space endows the set of maps with a geometry of
its own, which we exploit to define map operations in the spectral domain; we
also derive relationships with other existing representations (soft maps and
functional maps). To apply these ideas in practice, we discretize product
manifolds and their Laplace--Beltrami operators, and we introduce localized
spectral analysis of the product manifold as a novel tool for map processing.
Our framework applies to maps defined between and across 2D and 3D shapes
without requiring special adjustment, and it can be implemented efficiently
with simple operations on sparse matrices.Comment: Accepted to Computer Graphics Foru
Direct perturbation theory on the shift of Electron Spin Resonance
We formulate a direct and systematic perturbation theory on the shift of the
main paramagnetic peak in Electron Spin Resonance, and derive a general
expression up to second order. It is applied to one-dimensional XXZ and
transverse Ising models in the high field limit, to obtain explicit results
including the polarization dependence for arbitrary temperature.Comment: 5 pages (no figures) in REVTE
Electron Spin Resonance in S=1/2 antiferromagnetic chains
A systematic field-theory approach to Electron Spin Resonance (ESR) in the
quantum antiferromagnetic chain at low temperature (compared to the
exchange coupling ) is developed. In particular, effects of a transverse
staggered field and an exchange anisotropy (including a dipolar
interaction) on the ESR lineshape are discussed. In the lowest order
of perturbation theory, the linewidth is given as and
, respectively. In the case of a transverse staggered
field, the perturbative expansion diverges at lower temperature;
non-perturbative effects at very low temperature are discussed using exact
results on the sine-Gordon field theory. We also compare our field-theory
results with the predictions of Kubo-Tomita theory for the high-temperature
regime, and discuss the crossover between the two regimes. It is argued that a
naive application of the standard Kubo-Tomita theory to the
Dzyaloshinskii-Moriya interaction gives an incorrect result. A rigorous and
exact identity on the polarization dependence is derived for certain class of
anisotropy, and compared with the field-theory results.Comment: 53 pages in REVTEX, 7 figures in EPS included; revised version with
missing references and correction
Tensile strength assay comparing the resistance between two different autologous platelet concentrates (leucocyte-platelet rich fibrin versus advanced-platelet rich fibrin): a pilot study
Background: Since the leucocyte-platelet rich fibrin (L-PRF) was published in 2001, many studies have been developed, analyzing its properties, and also verifying new possibilities to improve it. Thereby, it emerges the advanced-platelet rich fibrin (A-PRF) with a protocol that optimizes the properties obtained by the L-PRF. Nonetheless, there is a gap in the literature to landmark the evolutive process concerning the mechanical properties in specific the resistance to tensile strength which consequently may influence the time for membrane degradation. Thus, this study had the goal to compare the resistance to the traction of membranes produced with the original L-PRF and A-PRF protocols, being the first to this direct comparison. Findings: The harvest of blood from a healthy single person, with no history of anticoagulant usage. We performed the protocols described in the literature, within a total of 13 membranes produced for each protocol (n = 26). Afterward, the membranes were prepared and submitted to a traction test assessing the maximal and the average traction achieved for each membrane. The data were analyzed statistically using the unpaired t test. Regarding average traction, A-PRF obtained a value of 0.0288 N mm−2 and L-PRF 0.0192 N mm−2 (p < 0.05 using unpaired t test). For maximal traction, A-PRF obtained 0.0752 N mm−2 and L-PRF 0.0425 N mm−2 (p < 0.05 using unpaired t test). Conclusion: With this study, it was possible to conclude that indeed A-PRF has a significative higher maximal traction score and higher average traction compared to L-PRF, indicating that it had a higher resistance when two opposing forces are applied.info:eu-repo/semantics/publishedVersio
Risk factors of post renal transplant anaemia among Sudanese patients, a study in three renal transplant centres
<p>Abstract</p> <p>Background</p> <p>There is a relative lack of recent information about late post kidney transplantation anaemia (PTA), especially in the developing countries; data are scarce about the prevalence and risk factors of PTA. Sudan was a leading country in Africa and Arab world in kidney transplantation. The first kidney transplantation in Sudan was in 1973.</p> <p>Methods</p> <p>This is a cross-sectional hospital analytic study enrolling all kidney transplanted recipients following in the transplant referral clinics at Ahmed Gassim, Selma and Ibn Sina Hospitals, Khartoum/Sudan, in the period from 1/8/2010 to 1/9/2010, clinical and laboratory data were obtained from 114 patients, anaemia was defined as Hb levels of < 13 g/dl for male patients and < 12 g/dl for female patients, exclusion criteria were pregnancy, below 18 years old patients, multiple organ transplantation, and patients with less than one year from the transplantation.</p> <p>Results</p> <p>The study showed that 39.5% of the patients were anaemic. Univariate analysis showed that late PTA is significantly associated with not using Erythropoietin (EPO) in the pre-transplant period (p = < 0.001), history of rejection (p = 0.003), longer time from transplantation (p = 0.015), and eGFR (p < 0.0001). Multivariate analysis showed that eGFR (p = < 0.001) and not use of EPO in the pre transplant period (p < 0.001) are strong predictors of PTA. The use of Angiotensin converting enzyme inhibitors/Angiotensin receptors blockers (ACEI/ARB), immunosuppressive treatments, presence or absence of co-morbidities, donor type and donor age are not significantly associated with late PTA.</p> <p>Conclusion</p> <p>The study concluded that late PTA is common and under recognized. Risk factors for late PTA include renal dysfunction, history of rejection, longer duration of transplantation and not using EPO in the pre-transplant period. Renal dysfunction and not using EPO in the pre-transplant period are major predictors of late PTA.</p
Augmented Cardiac Hypertrophy in Response to Pressure Overload in Mice Lacking ELTD1
BACKGROUND: Epidermal growth factor (EGF), latrophilin and seven transmembrane domain-containing protein 1 (ELTD1) is developmentally upregulated in the heart. Little is known about the relationship between ELTD1 and cardiac diseases. Therefore, we aimed to clarify the role of ELTD1 in pressure overload-induced cardiac hypertrophy. METHODS AND RESULTS: C57BL/6J wild-type (WT) mice and ELTD1-knockout (KO) mice were subjected to left ventricular pressure overload by descending aortic banding (AB). KO mice exhibited more unfavorable cardiac remodeling than WT mice 28 days post AB; this remodeling was characterized by aggravated cardiomyocyte hypertrophy, thickening of the ventricular walls, dilated chambers, increased fibrosis, and blunted systolic and diastolic cardiac function. Analysis of signaling pathways revealed enhanced extracellular signal-regulated kinase (ERK) and the c-Jun amino-terminal kinase (JNK) phosphorylation in response to ELTD1 deletion. CONCLUSIONS: ELTD1 deficiency exacerbates cardiac hypertrophy and cardiac function induced by AB-induced pressure overload by promoting both cardiomyocyte hypertrophy and cardiac fibrosis. These effects are suggested to originate from the activation of the ERK and JNK pathways, suggesting that ELTD1 is a potential target for therapies that prevent the development of cardiac disease
Dispersal of Adult Black Marlin (Istiompax indica) from a Great Barrier Reef Spawning Aggregation
The black marlin (Istiompax indica) is one of the largest bony fishes in the world with females capable of reaching a mass of over 700 kg. This highly migratory predator occurs in the tropical regions of the Pacific and Indian Oceans, and is the target of regional recreational and commercial fisheries. Through the sampling of ichthyoplankton and ovaries we provide evidence that the relatively high seasonal abundance of black marlin off the Great Barrier Reef is, in fact, a spawning aggregation. Furthermore, through the tracking of individual black marlin via satellite popup tags, we document the dispersal of adult black marlin away from the spawning aggregation, thereby identifying the catchment area for this spawning stock. Although tag shedding is an issue when studying billfish, we tentatively identify the catchment area for this stock of black marlin to extend throughout the Coral Sea, including the waters of Papua New Guinea, the Solomon Islands, Micronesia, New Caledonia, Kiribati, Vanuatu, Fiji, Tuvalu and Nauru
PKD1 and PKD2 mutations in Slovenian families with autosomal dominant polycystic kidney disease
BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous disorder caused by mutations in at least two different loci. Prior to performing mutation screening, if DNA samples of sufficient number of family members are available, it is worthwhile to assign the gene involved in disease progression by the genetic linkage analysis. METHODS: We collected samples from 36 Slovene ADPKD families and performed linkage analysis in 16 of them. Linkage was assessed by the use of microsatellite polymorphic markers, four in the case of PKD1 (KG8, AC2.5, CW3 and CW2) and five for PKD2 (D4S1534, D4S2929, D4S1542, D4S1563 and D4S423). Partial PKD1 mutation screening was undertaken by analysing exons 23 and 31–46 and PKD2 . RESULTS: Lod scores indicated linkage to PKD1 in six families and to PKD2 in two families. One family was linked to none and in seven families linkage to both genes was possible. Partial PKD1 mutation screening was performed in 33 patients (including 20 patients from the families where linkage analysis could not be performed). We analysed PKD2 in 2 patients where lod scores indicated linkage to PKD2 and in 7 families where linkage to both genes was possible. We detected six mutations and eight polymorphisms in PKD1 and one mutation and three polymorphisms in PKD2. CONCLUSION: In our study group of ADPKD patients we detected seven mutations: three frameshift, one missense, two nonsense and one putative splicing mutation. Three have been described previously and 4 are novel. Three newly described framesfift mutations in PKD1 seem to be associated with more severe clinical course of ADPKD. Previously described nonsense mutation in PKD2 seems to be associated with cysts in liver and milder clinical course
Platelet-rich plasma for regeneration of neural feedback pathways around dental implants: a concise review and outlook on future possibilities
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