58 research outputs found
A rare tumor of nasal bone in a child: osteoblastoma
No full textKavurt S, Corapcioglu F, Bay S, Ustundag E, Akansel G, Muezzinoglu B. A rare tumor of nasal bone in a child: osteoblastoma. Turk J Pediatr 2011; 53: 206-209
Staging and evaluation of neoadjuvant chemotherapy response with F-18-FDG PET/CT in NUT-midline carcinoma in a child: A case report and review of the literature
No full textCongenital pineoblastoma and parameningeal rhabdomyosarcoma: concurrent two embryonal tumors in a young infant
No full textBackground: Pineoblastomas are very rare brain tumors in fetus and neonates, comprising only 0.9% of congenital brain tumors. The occurrence of multiple tumors of different histopathologic types in the same individual is a rare event, most often encountered in hereditary cancer syndromes. Case report: We report a female fetus presented with a congenital pineoblastoma at the 32nd week of gestation, with hydrocephalus and concurrent parameningeal embryonal rhabdomyosarcoma in early infancy. Results: Cytogenetic analysis showed normal karyotype in the peripheral blood of the patient, and p53 mutational analysis revealed no germ line mutations. Discussion: This is the first case with concurrent congenital pineoblastoma and parameningeal embryonal rhabdomyosarcoma in early infancy. We suggest that concurrence of these tumors could be due to mutations in other tumor suppressor genes or secondary to exposure to unknown in utero factors
Fracturing fluid effects on Young's modulus and embedment in the Niobrara Formation
No full text2014 Spring.Includes illustrations (some color).Includes bibliographical references (pages 160-164).New discoveries of shale plays and their abundant resources have directed the petroleum industry towards their development. Production from shale reservoirs has grown significantly in the past few decades spurred by successful development of plays such as the Barnett and Bakken Shales. Due to their low permeability, hydraulic fracturing is a necessity for economic production in these reservoirs, and the success of these reservoirs is dependent on optimizing hydraulic fracturing designs which are in turn dictated by an understanding of the mechanical properties of these reservoirs. The geometric growth and conductivity of fractures in these reservoirs are influenced by many factors. Young's modulus reduction, which essentially means weakening of the formation, is one of these factors. This reduction damages the reservoir and makes embedment of proppants into the fracture face a detrimental effect on fracturing success. The goal of this research project is to focus on how different fracturing fluids change the Young's modulus of the Niobrara shale and how this change affect the proppant embedment and conductivity when commonly used proppants are subjected to pressure tests in the effected Niobrara shale samples. A series of tests and associated methodology were developed and applied to investigate how the Niobrara shale's Young's modulus is affected by various fracturing fluids and to quantify associated proppant embedment. In order to achieve this, core samples at various depths from the same well were selected from the cores. The selection was made based on mineralogy data. Samples containing the highest, lowest, and median calcite percentage and porosity were selected to be imaged with QEMSCAN in order to understand the mineralogy of the samples being used. Eight selected samples were then saturated with four fracturing fluids (freshwater, KCl, KCl+friction reducer, and freshwater+KCl substitute). Four of these samples were the "expansion" samples to see if the results were more dependent on the fluid selections. Two additional samples were heated with freshwater and KCl at 180°F for five days to investigate the heat effect on Young's modulus and embedment in comparison to room temperature experiments. In order to compare in-situ saturated Young's modulus values to dry Young's modulus values of cores obtained by nanoindenter, the Gassmann fluid substitution equation was used. This method showed significant Young's modulus difference between in-situ saturated and dry core values. The saturated/room temperature and saturated/heated cores were then subjected to 3030 psi for one hour while selected proppants were placed in between them. Four different proppant types (16/30 Brady, 20/40 Ottawa, 20/40 Ceramic, and 20/40 RCS) were used in this research. Various combinations of cores affected by fluids and proppants were made in order to simulate actual treatment designs. The cores were also scanned by scanning acoustic microscope (SAM) before and after they were subjected to pressure with proppants, so that a comparison could be made and embedment profiles could be observed. The very last method was to quantify the proppant embedment caused by proppants for cores that were treated by fracturing fluids. A profilometer was used in order to achieve this. In addition to developing the study methodology, experiments showed that Young's modulus decreased with fluid exposure regardless of the fracturing fluid type and also increased after some time of saturation. The magnitude of decrease in Young's modulus values was dependent on fluid type and saturation time and very significant reaching up to approximately 80%. The Young's modulus reduction is believed to be happening due to calcite minerals dissolving in the fluids. Higher reductions experienced by KCl based fluids are believed to be due to KCl causing a detrimental chemical reaction with the calcite minerals in the samples, or possibly due to the nanoindenter measuring salt precipitates and friction reducer residue on samples. Results also showed proppant embedment and crushing are inevitable under the tested circumstances and are related to stress contact effect as well as proppant type and fluid exposure
On Constitutive Equations and Effective Stress for Deformable, Double Porosity Media
No full textTuncay and Corapcioglu [1995] used volume averaging methods to derive an effective stress principle for the bulk volumetric strain in a deformable double-porosity medium. The coefficients of the matrix pore pressure and fracture pore pressure in their equation for the effective stress are shown to be identical to those which can be obtained from the constitutive equation approach of Berryman and Wang (1995). Representative values for a fractured Berea sandstone show that a change in pore pressure within matrix blocks produces about 10% of the volume change due to an equal but opposite change in confining pressure, whereas the same change in pore pressure within fractures is about 90% as effective. A similar result is true for Westerly granite. 1 Introduction The theory of poroelasticity lies at the intersection of mechanics of porous media and fluid flow within porous media. As a consequence, papers dealing with poroelasticity appear in journals that appeal primarily to one or the oth..
Biofilms in porous media: development of macroscopic transport equations via volume averaging with closure for local mass equilibrium conditions
No full textIn this work, we upscale a pore-scale description of mass transport in a porous medium containing biofilm to develop the relevant Darcy-scale equations. We begin with the pore-scale descriptions of mass transport, interphase mass transfer, and biologically-mediated reactions; these processes are then upscaled using the method of volume averaging to obtain the macroscale mass balance equations. We focus on the case of local mass equilibrium conditions where the averaged concentrations in the fluid and biological phases can be assumed to be proportional and for which a one-equation macroscopic model may be developed. We predict the effective dispersion tensor by a closure scheme that is solved for the cases of both simple and complex unit cells. The domain of validity of the approach is clearly identified, both theoretically and numerically, and unitless groupings indicating the domain of validity are reported
Post-traumatic stress disorder and risk factors in parents of children with the diagnosis of cancer
No full textAnalysis of 136 febrile neutropenic episodes in children with cancer: Evaluation of treatment effectiveness and cost
No full textIn this study, 136 febrile neutropenic episodes were overviewed retrospectively. Factors offering treatment success and cost were analyzed. Twenty percent of the episodes were microbiologically documented and 51% of the bacterial isolates were gram negatives. The most commonly used empirical therapies in febrile episodes were the combination of two drugs (58.0%), monotherapy (14.8%), and antibiotics plus fluconazole (20.6%). In lymphoproliferative tumors duration of fever and discharge from the hospital were longer. Administration of the hematopoietic growth factors shortened neither the duration of neutropenia nor fever and hospitalization. Treatment costs were higher in lymphoproliferative tumors, in bacteremia, and in episodes where glycopeptides, antifungal drugs, and hematopoietic growth factors were used. In conclusion, duration of neutropenia was a significant independent predictive factor for duration of fever. In the lymphoproliferative tumors, duration of fever was longer and cost of treatment was more than in the solid tumors
MLL-AF4 gene rearrangement in a child with Epstein-Baff virus-related posttransplant B-cell lymphoma
No full textRecipients of solid organ allografts are known to be at increased risk of developing Epstein-Barr virus-related posttransplant lymphoproliferative diseases. A 28-month-old boy who had received a heterotopic liver transplant presented with lymphadenopathy in the abdomen, multiple nodules in the liver, and bilateral renal infiltration 19 months after transplantation. He was diagnosed with a Burkitt-like lymphoma based on bone marrow examination and the finding that the blastic cells in bone marrow were EBER-1 positive. Cytogenetic analysis of the bone marrow cells showed an MLL-AF4 rearrangement. He was treated with a combined chemotherapy regimen. He has been in continuous complete remission for 15 months now
- …
