181 research outputs found
An Association of Multiple Well Differentiated Liposarcomas, Lipomatous Tissue and Hereditary Retinoblastoma
Well differentiated liposarcoma (atypical lipomatous tumour) is a low grade tumour, with no metastatic potential unless
dedifferentiation supervenes. When superficial, it recurs locally only occasionally after marginal excision. We present a
patient in whom bilateral childhood retinoblastoma was followed by later development of massive confluent areas of low
grade liposarcoma and lipomatous tissue affecting the upper extremities and trunk. We discuss the role of mutations in the
retinoblastoma gene (RB1) in linking these conditions and demonstrate the surgical management of an extremely unusual
and challenging case
A novel investigation into the application of non-destructive evaluation for vibration assessment and analysis of in-service pipes
Flow induced vibrations that are close to resonance frequencies are a major
problem in all oil and gas processing industries, so all piping systems require
regular condition monitoring and inspection to assess changes in their dynamic
characteristics and structural integrity in order to prevent catastrophic failures.
One of the main causes of pipe failure is weak support causing low frequency
high amplitude flow-induced vibration. This causes wear and tear, especially
near joints due to their dissimilar stiffness resulting in fatigue failure of joints
caused by vibration-induced high cyclic stress. Other contributing factors in pipe
failure are poor or inadequate design, poor workmanship during installation or
maintenance and inadequate or weak and flexible support. These pipes are
usually required to work non-stop for 24 hours a day 7 days a week for weeks,
months or years at a time. Regular monitoring and in-service dynamic analysis
should ensure continuous and safe operation. A novel method of non-destructive
testing and evaluation of these pipes, while in service, is proposed in this paper.
This technique will enable early detection and identification of the root causes of
any impending failure due to excess vibration as a result of cyclic force induced
by the flow. The method pinpoints the location of the impending failure prior to
condition-based maintenance procedures. The technique relies on the combined
application of Operating Deflection Shapes (ODS) analysis and computational
mechanics utilizing Finite Element Analysis (FEA), i.e. linear elastic stress
analysis. Any structural modification to the pipes and their supports can then be
applied virtually and their effects on the system can be analysed. The effect on
vibration levels is assessed and verified. The effect of any change in the forces
corresponding to changes in the Differential Pressure (DP) at constant flow rate
through the pipes can then be estimated. It was concluded that maintaining the
differential pressure above some “critical” threshold ensures the pipe operates
under the allowable dynamic stress for a theoretically “indefinite” life cycle
A new class of pluripotent stem cell cytotoxic small molecules
10.1371/journal.pone.0085039PLoS ONE93-POLN
Genetics of Mechanosensation in the Heart
Mechanosensation (the ultimate conversion of a mechanical stimulus into a biochemical signal) as well as mechanotransduction (transmission of mechanically induced signals) belong to the most fundamental processes in biology. These effects, because of their dynamic nature, are particularly important for the cardiovascular system. Therefore, it is not surprising that defects in cardiac mechanosensation, are associated with various types of cardiomyopathy and heart failure. However, our current knowledge regarding the genetic basis of impaired mechanosensation in the cardiovascular system is beginning to shed light on this subject and is at the centre of this brief review
Evaluating the role of human papillomaviruses in conjunctival neoplasia
Mucosal, cutaneous and Epidermodysplasia verruciformis (EV)-related human papillomaviruses (HPVs) were searched by broad-spectrum PCR in 86 conjunctival neoplasia biopsies and 63 conjunctival non-neoplastic control tissue from Ugandan subjects. Seven different EV-related HPV types, including a putative new HPV, and two mucosal HPVs were detected in 25% (14 out of 56) of HIV-positive, in 10% (three out of 30) of HIV-negative conjunctival neoplasia samples, and rarely (0–1.6%) in control subjects. The absence of high-risk HPVs and the low detection frequency of EV-related HPV types in more advanced tumour stages (10%) raise doubts about their role in conjunctival carcinomas
Mutation and deletion analysis of GFRα-1, encoding the co-receptor for the GDNF/RET complex, in human brain tumours
Glial cell line-derived neurotrophic factor (GDNF) plays a key role in the control of vertebrate neuron survival and differentiation in both the central and peripheral nervous systems. GDNF preferentially binds to GFRα-1 which then interacts with the receptor tyrosine kinase RET. We investigated a panel of 36 independent cases of mainly advanced sporadic brain tumours for the presence of mutations in GDNF and GFRα-1. No mutations were found in the coding region of GDNF. We identified six previously described GFRα-1 polymorphisms, two of which lead to an amino acid change. In 15 of 36 brain tumours, all polymorphic variants appeared to be homozygous. Of these 15 tumours, one also had a rare, apparently homozygous, sequence variant at codon 361. Because of the rarity of the combination of homozygous sequence variants, analysis for hemizygous deletion was pursued in the 15 samples and loss of heterozygosity was found in 11 tumours. Our data suggest that intragenic point mutations of GDNF or GFRα-1 are not a common aetiologic event in brain tumours. However, either deletion of GFRα-1 and/or nearby genes may contribute to the pathogenesis of these tumours
HIV and HPV infections and ocular surface squamous neoplasia: systematic review and meta-analysis.
BACKGROUND: The frequency of ocular surface squamous neoplasias (OSSNs) has been increasing in populations with a high prevalence of infection with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) and infection with human papillomavirus (HPV). We aimed to quantify the association between HIV/AIDS and HPV infection and OSSN, through systematic review and meta-analysis. METHODS: The articles providing data on the association between HIV/AIDS and/or HPV infection and OSSN were identified in MEDLINE, SCOPUS and EMBASE searched up to May 2013, and through backward citation tracking. The DerSimonian and Laird method was used to compute summary relative risk (RR) estimates and 95% confidence intervals (95% CI). Heterogeneity was quantified with the I(2) statistic. RESULTS: HIV/AIDS was strongly associated with an increased risk of OSSN (summary RR=8.06, 95% CI: 5.29-12.30, I(2)=56.0%, 12 studies). The summary RR estimate for the infection with mucosal HPV subtypes was 3.13 (95% CI: 1.72-5.71, I(2)=45.6%, 16 studies). Four studies addressed the association between both cutaneous and mucosal HPV subtypes and OSSN; the summary RR estimates were 3.52 (95% CI: 1.23-10.08, I(2)=21.8%) and 1.08 (95% CI: 0.57-2.05, I(2)=0.0%), respectively. CONCLUSION: Human immunodeficiency virus infection increases the risk of OSSN by nearly eight-fold. Regarding HPV infection, only the cutaneous subtypes seem to be a risk factor
The CD14 functional gene polymorphism -260 C>T is not involved in either the susceptibility to Chlamydia trachomatis infection or the development of tubal pathology
BACKGROUND: The functional polymorphism -260 C>T in the LPS sensing TLR4 co-receptor CD14 gene enhances the transcriptional activity and results in a higher CD14 receptor density. Individuals carrying the T/T genotype also have significantly higher serum levels of soluble CD14. The T allele of this polymorphism has recently been linked to Chlamydia pneumoniae infection. We investigated the role of the CD14 -260 C>T polymorphism in the susceptibility to and severity (defined as subfertility and/or tubal pathology) of C. trachomatis infection in Dutch Caucasian women. METHODS: The different CD14 -260 C>T genotypes were assessed by PCR-based RFLP analysis in three cohorts: 1) A cohort (n = 576) of women attending a STD clinic, 2) a cohort (n = 253) of women with subfertility, and 3) an ethnically matched control cohort (n = 170). The following variables were used in the analysis: In cohort 1 the CT-DNA status, CT IgG serology status, self-reported symptoms and in cohort 2, the CT IgG serology status and the tubal status at laparoscopy. RESULTS: In the control cohort the CC, CT and TT genotype distribution was: 28.2%, 48.2%, and 23.5% respectively. No differences were found in the overall prevalence of CD14 -260 genotypes (28.1%, 50.7%, and 21.2%) in cohort 1 when compared to the control cohort. Also no differences were observed in women with or without CT-DNA, with or without serological CT responses, with or without symptoms, or in combinations of these three variables. In subfertile women with tubal pathology (cohort 2, n = 50) the genotype distribution was 28.0%, 48.0%, and 24.0% and in subfertile women without tubal pathology (n = 203), 27.6%, 49.3% and 23.2%. The genotype distribution was unchanged when CT IgG status was introduced in the analyses. CONCLUSION: The CD14 -260 C>T genotype distributions were identical in all three cohorts, showing that this polymorphism is not involved in the susceptibility to or severity of sequelae of C. trachomatis infection
Minería de datos para el descubrimiento de patrones en enfermedades respiratorias en Bogotá, Colombia
Trabajo de InvestigaciónEl presente proyecto se basa en la aplicación de minería de datos mediante el algoritmo de clustering K- means que permita la generación de un modelo descriptivo con el análisis de los datos y con el objetivo de identificar posibles comportamientos en enfermedades respiratorias en la ciudad de Bogotá.
El conjunto de clústeres generados por la herramienta RapidMiner es la
recopilación de datos de un periodo de cinco años de 2012 a 2016, en donde se contemplan el número de casos asociados a 184 diagnósticos de enfermedades respiratorias y la edad de los pacientes corresponde de 0 a 5 años.Trabajo de Investigación1. GENERALIDADES
2. OBJETIVOS
3. JUSTIFICACIÓN
4. DELIMITACIÓN
5. MARCO REFERENCIAL
6. METODOLOGÍA
7. FUENTES DE EXTRACCIÓN Y SUS VARIABLES
8. DISEÑO
9. SELECCIÓN DE ALGORITMOS DE CLUSTERING
10. RECONOCER PATRONES A PARTIR DE LA INFORMACIÓN RECOPILADA
11. CONCLUSIONES
12. TRABAJOS FUTUROS 13. REFERENCIAS BIBLIOGRÁFICAS
14. ANEXOSPregradoIngeniero de Sistema
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