176 research outputs found
A Thermo-Compositional Model of the African Cratonic Lithosphere
Recently, the continually increasing availability of seismic data has allowed high-resolution imaging of lithospheric structure beneath the African cratons. In this study, S-wave seismic tomography is combined with high resolution satellite gravity data in an integrated approach to investigate the structure of the cratonic lithosphere of Africa. A new model for the Moho depth and data on the crustal density structure is employed along with global dynamic models to calculate residual topography and mantle gravity residuals. Corrections for thermal effects of an initially juvenile mantle are estimated based on S-wave tomography and mineral physics. Joint inversion of the residuals yields necessary compositional adjustments that allow to recalculate the thermal effects. After several iterations, we obtain a consistent model of upper mantle temperature, thermal and compositional density variations, and Mg# as a measure of depletion, as well as an improved crustal density model. Our results show that thick and cold depleted lithosphere underlies West African, northern to central eastern Congo, and Zimbabwe Cratons. However, for most of these regions, the areal extent of their depleted lithosphere differs from the respective exposed Archean shields. Meanwhile, the lithosphere of Uganda, Tanzania, most of eastern and southern Congo, and the Kaapvaal Craton is thinner, warmer, and shows little or no depletion. Furthermore, the results allow to infer that the lithosphere of the exposed Archean shields of Congo and West African cratons was depleted before the single blocks were merged into their respective cratons
Density structure and isostasy of the lithosphere in Egypt and their relation to seismicity
A joint analysis of the new satellite–terrestrial gravity field
model with recent data on the crustal structure and seismic tomography
was conducted to create an integrative model of the crust and upper
mantle and to investigate the relation of the density structure and the
isostatic state of the lithosphere to the seismicity of Egypt. We identified
the distinct fragmentation of the lithosphere of Egypt in several blocks.
This division is closely related to the seismicity patterns in this region.
The relatively dense and strong lithosphere in the Nile Delta limits the
seismic activity within this area, while earthquakes are mainly associated
with the boundaries of this block. In the same way, the relatively strong
lithosphere in the Isthmus of Suez and northern Mediterranean prevents the Gulf
of Suez from opening further. The central part of Egypt is generally
characterized by an increased density of the mantle, which extends to the
Mediterranean at a depth of 100 km. This anomaly deepens southward to Gilf
Kebir and eastward to the Eastern Desert. The average density of the
crystalline crust is generally reduced in this zone, indicating the increased
thickness of the upper crust. The low-density anomaly under the northern Red
Sea is limited to 100–125 km, confirming the passive origin of the
extension. Most of the earthquakes occur in the crust and uppermost mantle in
this structure due to the hot and weak upper mantle underneath. Furthermore,
an asymmetric lithosphere structure is observed across the northern Red Sea.
The isostatic anomalies show the fragmentation of the crust of Sinai with the
high-density central block. Strong variations in the isostatic anomalies are
correlated with the high level of seismicity around Sinai. This tendency is
also evident in the northern Red Sea, east of the Nile Valley, and in parts of
the Western Desert.</p
Three-dimensional cephalometric evaluation of maxillary growth following in utero repair of cleft lip and alveolar-like defects in the mid-gestational sheep model
Objective: To evaluate maxillary growth following in utero repair of surgically created cleft lip and alveolar (CLA)-like defects by means of three-dimensional (3D) computer tomographic (CT) cephalometric analysis in the mid-gestational sheep model. Methods: In 12 sheep fetuses a unilateral CLA-like defect was created in utero (untreated control group: 4 fetuses). Four different bone grafts were used for the alveolar defect closure. After euthanasia, CT scans of the skulls of the fetuses, 3D re-constructions, and a 3D-CT cephalometric analysis were performed. Results: The comparisons between the operated and nonoperated skull sides as well as of the maxillary asymmetry among the experimental groups revealed no statistically significant differences of the 12 variables used. Conclusions: None of the surgical approaches used for the in utero correction of CLA-like defects seem to affect significantly postsurgical maxillary growth; however, when bone graft healing takes place, a tendency for almost normal maxillary growth can be observed. Copyright (c) 2006 S. Karger AG, Basel
Survival associated pathway identification with group Lp penalized global AUC maximization
It has been demonstrated that genes in a cell do not act independently. They interact with one another to complete certain biological processes or to implement certain molecular functions. How to incorporate biological pathways or functional groups into the model and identify survival associated gene pathways is still a challenging problem. In this paper, we propose a novel iterative gradient based method for survival analysis with group Lp penalized global AUC summary maximization. Unlike LASSO, Lp (p < 1) (with its special implementation entitled adaptive LASSO) is asymptotic unbiased and has oracle properties [1]. We first extend Lp for individual gene identification to group Lp penalty for pathway selection, and then develop a novel iterative gradient algorithm for penalized global AUC summary maximization (IGGAUCS). This method incorporates the genetic pathways into global AUC summary maximization and identifies survival associated pathways instead of individual genes. The tuning parameters are determined using 10-fold cross validation with training data only. The prediction performance is evaluated using test data. We apply the proposed method to survival outcome analysis with gene expression profile and identify multiple pathways simultaneously. Experimental results with simulation and gene expression data demonstrate that the proposed procedures can be used for identifying important biological pathways that are related to survival phenotype and for building a parsimonious model for predicting the survival times
Management of Orofacial Manifestations of Juvenile Idiopathic Arthritis: Interdisciplinary Consensus-Based Recommendations
Involvement of the temporomandibular joint (TMJ) is common in juvenile idiopathic arthritis (JIA). TMJ arthritis can
lead to orofacial symptoms, orofacial dysfunction, and dentofacial deformity with negative impact on quality of life.
Management involves interdisciplinary collaboration. No current recommendations exist to guide clinical management.
We undertook this study to develop consensus-based interdisciplinary recommendations for management of orofacial
manifestations of JIA, and to create a future research agenda related to management of TMJ arthritis in children with
JIA. Recommendations were developed using online surveying of relevant stakeholders, systematic literature review,
evidence-informed generation of recommendations during 2 consensus meetings, and Delphi study iterations involving external experts. The process included disciplines involved in the care of orofacial manifestations of JIA: pediatric
rheumatology, radiology, orthodontics, oral and maxillofacial surgery, orofacial pain specialists, and pediatric dentistry.
Recommendations were accepted if agreement was >80% during a final Delphi study. Three overarching management
principles and 12 recommendations for interdisciplinary management of orofacial manifestations of JIA were outlined.
The 12 recommendations pertained to diagnosis (n = 4), treatment of TMJ arthritis (active TMJ inflammation) (n = 2),
treatment of TMJ dysfunction and symptoms (n = 3), treatment of arthritis-related dentofacial deformity (n = 2), and
other aspects related to JIA (n = 1). Additionally, a future interdisciplinary research agenda was developed. These are
the first interdisciplinary recommendations to guide clinical management of TMJ JIA. The 3 overarching principles
and 12 recommendations fill an important gap in current clinical practice. They emphasize the importance of an interdisciplinary approach to diagnosis and management of orofacial manifestations of JIA
Giant cell tumor of the uterus: case report and response to chemotherapy
BACKGROUND: Giant cell tumor (GCT) is usually a benign but locally aggressive primary bone neoplasm in which monocytic macrophage/osteoclast precursor cells and multinucleated osteoclast-like giant cells infiltrate the tumor. The etiology of GCT is unknown, however the tumor cells of GCT have been reported to produce chemoattractants that can attract osteoclasts and osteoclast precursors. Rarely, GCT can originate at extraosseous sites. More rarely, GCT may exhibit a much more aggressive phenotype. The role of chemotherapy in metastatic GCT is not well defined. CASE PRESENTATION: We report a case of an aggressive GCT of the uterus with rapidly growing lung metastases, and its response to chemotherapy with pegylated-liposomal doxorubicin, ifosfamide, and bevacizumab, along with a review of the literature. CONCLUSION: Aggressive metastasizing GCT may arise in the uterus, and may respond to combination chemotherapy
Metastable monotectic phase separation in Co–Cu alloys
The liquid phase separation behaviour of metastable monotectic Co–Cu alloys was investigated as a function of cooling rate using a 6.5 m drop-tube facility. A range of liquid phase separated morphologies were observed including stable two-layer core–shell, evolving core–shell and dendritic structures. It was found that in the core–shell structures the core was always in the higher melting point (Co-rich) phase, irrespective of the core and shell volume fraction. In Cu–50 at% Co alloy, high cooling rates were observed to yield two episodes of liquid phase separation, corresponding to binodal, followed by spinodal decomposition. The resulting structure comprised a core–shell structure in which the Co-rich core contained a very fine dispersion of Cu-rich particles with a Cu-rich shell which may, or may not, contain a similar dispersion of Co-rich particles
Biodiversity and characterization of gram-positive, catalase-positive cocci isolated from pastırma produced under different curing processes
The aim of this study was to determine the effects of different curing temperatures (4 °C or 10 °C) and agents (KNO 3 or NaNO 2 ) on microbiological and physicochemical properties of pastırma and diversity of gram-positive, catalase-positive cocci (GCC + ) and also to investigate some technological properties of the strains. Four different groups of pastırma were produced applying different curing temperatures and agents. After production, GCC + isolated from pastırma were subjected to phenotypic and genotypic (16S rRNA sequencing) identification. Genotypically characterized strains were evaluated for their technological properties. In all groups, a w and pH were observed to be under 0.90 and over 5.5, respectively. In genotypic identification, 45 isolates were identified as Staphylococcus vitulinus, while other isolates identified were S. equorum (n = 15), S. saprophyticus (n = 15), and S. xylosus (n = 12). All of the strains could grow at different salt concentrations (8% and 15%) and temperatures (4 °C, 10 °C, and 37 °C). Four strains of S. saprophyticus showed strong lipolytic activity while nine strains of S. vitulinus had strong proteolytic activity. This study showed that different curing temperatures and agents are particularly effective on the microflora in pastırma; however, these factors do not cause a high diversity in GCC + in terms of species. © TÜBİTA
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