1,194 research outputs found
Tracheocutaneous fistula in patients undergoing supracricoid partial laryngectomy: the role of chronic aspiration
The aim of the present retrospective controlled study was to analyse and compare risk factors for tracheocutaneous fistula in patients who received tracheostomy after supracricoid partial laryngectomy with those who received tracheostomy for other causes. We enrolled 39 patients with tracheocutaneous fistulas who were divided into two groups. The first received temporary tracheostomy for supracricoid partial laryngectomies (n = 21), while the control group consisted of patients who received temporary tracheostomy for other causes (n = 18). Risk factors believed to play a role in the pathogenesis of tracheocutaneous fistula were examined including advanced age, cardiopathy, local infections, radiotherapy, elevated body mass index, malnutrition, decannulation time and aspiration grade. The Leipzig and Pearson scale score was significantly higher in the supracricoid partial laryngectomy group (p = 0.006 and 0.031 for univariate and multivariate analyses, respectively). The penetration/aspiration scale score was significantly higher in the supracricoid partial laryngectomy group as determined by univariate analysis (p = 0.014). The decannulation time was significantly lower in the supracricoid partial laryngectomy group (p = 0.004 and 0.0004 for univariate and multivariate analyses, respectively). The number of surgical closures for tracheocutaneous fistula was significantly higher in the supracricoid partial laryngectomy group by univariate analysis (p = 0.027). These results suggest that chronic aspiration and related cough may be important pathogenic factors for tracheocutaneous fistula and could be responsible for the significantly higher rates of closure failure in patients after supracricoid partial laryngectomy
The CP12 protein family: a thioredoxin-mediated metabolic switch?
CP12 is a small, redox-sensitive protein, representatives of which are found in most photosynthetic organisms, including cyanobacteria, diatoms, red and green algae, and higher plants. The only clearly defined function for CP12 in any organism is in the thioredoxin-mediated regulation of the Calvin-Benson cycle. CP12 mediates the formation of a complex between glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) in response to changes in light intensity. Under low light, the formation of the GAPDH/PRK/CP12 complex results in a reduction in the activity of both PRK and GAPDH and, under high light conditions, thioredoxin mediates the disassociation of the complex resulting in an increase in both GAPDH and PRK activity. Although the role of CP12 in the redox-mediated formation of the GAPDH/PRK/CP12 multiprotein complex has been clearly demonstrated, a number of studies now provide evidence that the CP12 proteins may play a wider role. In Arabidopsis thaliana CP12 is expressed in a range of tissue including roots, flowers, and seeds and antisense suppression of tobacco CP12 disrupts metabolism and impacts on growth and development. Furthermore, in addition to the higher plant genomes which encode up to three forms of CP12, analysis of cyanobacterial genomes has revealed that, not only are there multiple forms of the CP12 protein, but that in these organisms CP12 is also found fused to cystathionine-β-synthase domain containing proteins. In this review we present the latest information on the CP12 protein family and explore the possibility that CP12 proteins form part of a redox-mediated metabolic switch, allowing organisms to respond to rapid changes in the external environment. © 2014 López-Calcagno, Howard and Raines
Internal Anisotropy of Collision Cascades
We investigate the internal anisotropy of collision cascades arising from the
branching structure. We show that the global fractal dimension cannot give an
adequate description of the geometrical structure of cascades because it is
insensitive to the internal anisotropy. In order to give a more elaborate
description we introduce an angular correlation function, which takes into
account the direction of the local growth of the branches of the cascades. It
is demonstrated that the angular correlation function gives a quantitative
description of the directionality and the interrelation of branches. The power
law decay of the angular correlation is evidenced and characterized by an
exponent and an angular correlation length different from the radius of
gyration. It is demonstrated that the overlapping of subcascades has a strong
effect on the angular correlation.Comment: RevteX, 8 pages, 6 .eps figures include
Graph-Based Shape Analysis Beyond Context-Freeness
We develop a shape analysis for reasoning about relational properties of data
structures. Both the concrete and the abstract domain are represented by
hypergraphs. The analysis is parameterized by user-supplied indexed graph
grammars to guide concretization and abstraction. This novel extension of
context-free graph grammars is powerful enough to model complex data structures
such as balanced binary trees with parent pointers, while preserving most
desirable properties of context-free graph grammars. One strength of our
analysis is that no artifacts apart from grammars are required from the user;
it thus offers a high degree of automation. We implemented our analysis and
successfully applied it to various programs manipulating AVL trees,
(doubly-linked) lists, and combinations of both
Verifying linearizability on TSO architectures
Linearizability is the standard correctness criterion for fine-grained, non-atomic concurrent algorithms, and a variety of methods for verifying linearizability have been developed. However, most approaches assume a sequentially consistent memory model, which is not always realised in practice. In this paper we define linearizability on a weak memory model: the TSO (Total Store Order) memory model, which is implemented in the x86 multicore architecture. We also show how a simulation-based proof method can be adapted to verify linearizability for algorithms running on TSO architectures. We demonstrate our approach on a typical concurrent algorithm, spinlock, and prove it linearizable using our simulation-based approach. Previous approaches to proving linearizabilty on TSO architectures have required a modification to the algorithm's natural abstract specification. Our proof method is the first, to our knowledge, for proving correctness without the need for such modification
Building a Prediction Model for Vacuum-Assisted Operative Vaginal Delivery Risk
Aim: The objective of this study was to evaluate the risk factors
for operative vaginal delivery and to propose a new nomogram
for predicting the risk. Methods: We retrospectively
analyzed the data of 1,955 pregnancies that occurred in
our clinic between the years 2007 and 2008. Included were
singleton pregnancies with labor diagnosis after the 36th
gestational week in which spontaneous or operative vaginal
deliveries occurred. In this study, the operative delivery was
carried out exclusively by vacuum extraction. Results: After
univariate analysis and multivariate logistic regression stepwise
model selection, maternal age, nulliparity, medically assisted
procreation, gestational age at birth, male fetus, epidural
analgesia and medical induction of labor were found
to be the most predictive variables for operative vaginal delivery.
Considering these factors we propose a new nomogram
for an objectified determination of the risk of operative
vaginal delivery. Conclusions: The new nomogram we propose
could be an important tool for an objectified determination
of the risk of operative vaginal delivery by vacuum
extraction in individualized patient counseling
Defining best practices in the management of geothermal exploration data
International audienceThe objective of this work is to define best practices in the management of geothermal exploration data. This study builds on a questionnaire to survey the geothermal data management practices in mature geothermal markets. The inquiry targeted public Regulatory entities with overview of geothermal resources as well as public and private developers. Topics covered in the questionnaire range from the country status to the database set up. The questionnaire focused on the specifications, usage and investments required for installing/maintaining information systems capable of managing exploration data. In addition, information on the different regulatory frameworks and company policies for managing/sharing exploration data has been gathered to identify the requirements imposed on the design of information systems. The responses were analyzed to identify commonalities in data management practices. They reveal that installing an Information System (IS) is the best practice to systematically and securely manage exploration data. They also provide recommendations with respect to the regulatory framework, data types, data collection methodologies, data storage, data quality control, data accessibility and dissemination, IS architecture, financial investments and human resources required to develop a state-of-the art IS. These results will guide the design of future technical assistance programs for beneficiaries of World Bank support to geothermal exploration activities and it is our belief that they will be beneficial for the geothermal sector at large
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