223 research outputs found
Design of a Customized Neck Orthosis for FDM Manufacturing with a New Sustainable Bio-composite
The interest in developing customized external orthopaedic devices,
thanks to the advent of Additive Manufacturing (AM), has grown in recent
years. Greater attention was focused on upper limb casts, while applications to
other body’s parts, such as the neck, were less investigated. In this paper the
computer aided design (CAD) modelling, assessment and 3D printing with
fused deposition modelling (FDM) of a customized neck orthosis are reported.
The modelling, based on anatomic data of a volunteer subject, was aimed to
obtain a lightweight, ventilated, hygienic and comfortable orthosis compared to
the produced medical devices generally used for neck injuries. CAD models
with different geometrical patterns, introduced for lightening and improving
breathability, were considered, specifically, a honeycomb pattern and an elliptical
holes pattern. These models were structurally assessed by means of finite
elements analysis (FEA). Furthermore, an innovative composite material was
considered for 3D printing. The material, Hemp Bio-Plastic® (HBP), composed
by polylactic acid (PLA) and hemp shives, offers different advantages including
lightweight, improved superficial finish and antibacterial properties. The results
obtained in terms of design methodology and manufacturing by 3D printing of a
prototype have shown the feasibility to develop customized cervical orthoses,
with potentially improved performance with respect to cervical collars available
on the market also thanks to the use of the innovative composite material
The impact of excluding or including Death Certificate Initiated (DCI) cases on estimated cancer survival: A simulation study
Background
Population-based cancer registries strive to cover all cancer cases diagnosed within the population, but some cases will always be missed and no register is 100 % complete. Many cancer registries use death certificates to identify additional cases not captured through other routine sources, to hopefully add a large proportion of the missed cases. Cases notified through this route, who would not have been captured without death certificate information, are referred to as Death Certificate Initiated (DCI) cases. Inclusion of DCI cases in cancer registries increases completeness and is important for estimating cancer incidence. However, inclusion of DCI cases will generally lead to biased estimates of cancer survival, but the same is often also true if excluding DCI cases. Missed cases are probably not a random sample of all cancer cases, but rather cases with poor prognosis. Further, DCI cases have poorer prognosis than missed cases in general, since they have all died with cancer mentioned on the death certificates.
Methods
We performed a simulation study to estimate the impact of including or excluding DCI cases on cancer survival estimates, under different scenarios.
Results
We demonstrated that including DCI cases underestimates survival. The exclusion of DCI cases gives unbiased survival estimates if missed cases are a random sample of all cancer cases, while survival is overestimated if these have poorer prognosis.
Conclusion
In our most extreme scenarios, with 25 % of cases initially missed, the usual practice of including DCI cases underestimated 5-year survival by at most 3 percentage points
Exploring the impact of cancer registry completeness on international cancer survival differences: a simulation study
Background
Data from population-based cancer registries are often used to compare cancer survival between countries or regions. The ICBP SURVMARK-2 study is an international partnership aiming to quantify and explore the reasons behind survival differences across high-income countries. However, the magnitude and relevance of differences in cancer survival between countries have been questioned, as it is argued that observed survival variations may be explained, at least in part, by differences in cancer registration practice, completeness and the availability and quality of the respective data sources.
Methods
As part of the ICBP SURVMARK-2 study, we used a simulation approach to better understand how differences in completeness, the characteristics of those missed and inclusion of cases found from death certificates can impact on cancer survival estimates.
Results
Bias in 1- and 5-year net survival estimates for 216 simulated scenarios is presented. Out of the investigated factors, the proportion of cases not registered through sources other than death certificates, had the largest impact on survival estimates.
Conclusion
Our results show that the differences in registration practice between participating countries could in our most extreme scenarios explain only a part of the largest observed differences in cancer survival
Predictors of well child care adherence over time in a cohort of urban Medicaid-eligible infants
<p>Abstract</p> <p>Background</p> <p>Changes in well child care (WCC) adherence over time have not previously been examined. Our objective is to describe adherence rates to WCC over time in a low-income urban population of infants 0-24 months of age, and to identify predictors of WCC adherence in this population.</p> <p>Methods</p> <p>This is a secondary analysis of a cohort of Medicaid-eligible children followed from birth to 2 years between 2005 and 2008 with structured telephone surveys to assess maternal well-being, social support, and household and demographic information. For the 260 children attending 4 urban pediatric practices, WCC adherence was assessed based on visit data abstracted from electronic medical records. A random-intercept mixed effects logit model clustered on subject was used.</p> <p>Results</p> <p>92% of the mothers were African-American, 27% had not finished high school, 87% were single, and 43% earned < $500/month; mean age was 23. WCC adherence decreased from 88% at 6 months to 47% (12 mo), 44% (18 mo), and 67% (24 mo). The difference across time periods was statistically significant (p < 0.001). Married (OR 1.71, p = 0.02) and primiparous (OR 1.89, p < 0.001) mothers had significantly greater odds of adherence, along with women who reported having been adherent to prenatal care visits (OR 1.49, p = 0.03) and those with the lowest household income (OR 1.40, p = 0.03).</p> <p>Conclusions</p> <p>Maternal education efforts should emphasize the importance of establishing WCC, especially for mothers of more than one child. Further studies using larger, more broadly defined populations are needed to confirm our findings that efforts to increase WCC adherence should be intensified after 6 months of age, particularly for children at higher risk.</p
Mother and Adolescent Reports of Associations Between Child Behavior Problems and Mother-Child Relationship Qualities: Separating Shared Variance from Individual Variance
This study contrasts results from different correlational methods for examining links between mother and child (N = 72 dyads) reports of early adolescent (M = 11.5 years) behavior problems and relationship negativity and support. Simple (Pearson) correlations revealed a consistent pattern of statistically significant associations, regardless of whether scores came from the same reporter or from different reporters. When correlations between behavior problems and relationship quality differed, within-reporter correlations were always greater in magnitude than between-reporter correlations. Dyadic (common fate) analyses designed for interdependent data decomposed within-reporter correlations into variance shared across reporters (dyadic correlations) and variance unique to specific reporters (individual correlations). Dyadic correlations were responsible for most associations between adolescent behavior problems and relationship negativity; after partitioning variance shared across reporters, no individual correlations emerged as statistically significant. In contrast, adolescent behavior problems were linked to relationship support via both shared variance and variance unique to maternal perceptions. Dyadic analyses provide a parsimonious alternative to multiple contrasts in instances when identical measures have been collected from multiple reporters. Findings from these analyses indicate that same-reporter variance bias should not be assumed in the absence of dyadic statistical analyses
Ribosomal oxygenases are structurally conserved from prokaryotes to humans
2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases
An unusual cause of granulomatous disease
BACKGROUND: Chronic granulomatous disease (CGD) is an inherited disorder of phagocytic cells caused by an inability to generate active microbicidal oxygen species required kill certain types of fungi and bacteria. This leads to recurrent life-threatening bacterial and fungal infections with tissue granuloma formation. CASE PRESENTATION: We describe a case of X-linked Chronic granulomatous disease (CGD) diagnosed in an 18-year-old male. He initially presented with granulomatous disease mimicking sarcoidosis and was treated with corticosteroids. He subsequently developed Burkholderia cepacia complex pneumonia and further investigation confirmed a diagnosis of CGD. CONCLUSION: Milder phenotypes of CGD are now being recognised. CGD should be considered in patients of any age with granulomatous diseases, especially if there is a history of recurrent or atypical infection
Genome-wide association study identifies a variant in HDAC9 associated with large vessel ischemic stroke
Genetic factors have been implicated in stroke risk but few replicated associations have been reported. We conducted a genome-wide association study (GWAS) in ischemic stroke and its subtypes in 3,548 cases and 5,972 controls, all of European ancestry. Replication of potential
signals was performed in 5,859 cases and 6,281 controls. We replicated reported associations between variants close to PITX2 and ZFHX3 with cardioembolic stroke, and a 9p21 locus with large vessel stroke. We identified a novel association for a SNP within the histone deacetylase 9(HDAC9) gene on chromosome 7p21.1 which was associated with large vessel stroke including additional replication in a further 735 cases and 28583 controls (rs11984041, combined P =
1.87×10−11, OR=1.42 (95% CI) 1.28-1.57). All four loci exhibit evidence for heterogeneity of effect across the stroke subtypes, with some, and possibly all, affecting risk for only one subtype. This suggests differing genetic architectures for different stroke subtypes
βB1-Crystallin: Thermodynamic Profiles of Molecular Interactions
β-Crystallins are structural proteins maintaining eye lens transparency and opacification. Previous work demonstrated that dimerization of both βA3 and βB2 crystallins (βA3 and βB2) involves endothermic enthalpy of association (∼8 kcal/mol) mediated by hydrophobic interactions.Thermodynamic profiles of the associations of dimeric βA3 and βB1 and tetrameric βB1/βA3 were measured using sedimentation equilibrium. The homo- and heteromolecular associations of βB1 crystallin are dominated by exothermic enthalpy (-13.3 and -24.5 kcal/mol, respectively).Global thermodynamics of βB1 interactions suggest a role in the formation of stable protein complexes in the lens via specific van der Waals contacts, hydrogen bonds and salt bridges whereas those β-crystallins which associate by predominately hydrophobic forces participate in a weaker protein associations
Genetic interactions between a phospholipase A2 and the Rim101 pathway components in S. cerevisiae reveal a role for this pathway in response to changes in membrane composition and shape
Modulating composition and shape of biological membranes is an emerging mode of regulation of cellular processes. We investigated the global effects that such perturbations have on a model eukaryotic cell. Phospholipases A2 (PLA2s), enzymes that cleave one fatty acid molecule from membrane phospholipids, exert their biological activities through affecting both membrane composition and shape. We have conducted a genome-wide analysis of cellular effects of a PLA2 in the yeast Saccharomyces cerevisiae as a model system. We demonstrate functional genetic and biochemical interactions between PLA2 activity and the Rim101 signaling pathway in S. cerevisiae. Our results suggest that the composition and/or the shape of the endosomal membrane affect the Rim101 pathway. We describe a genetically and functionally related network, consisting of components of the Rim101 pathway and the prefoldin, retromer and SWR1 complexes, and predict its functional relation to PLA2 activity in a model eukaryotic cell. This study provides a list of the players involved in the global response to changes in membrane composition and shape in a model eukaryotic cell, and further studies are needed to understand the precise molecular mechanisms connecting them
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