6,255 research outputs found
Aberrant Glycosylation in Cancer: A Novel Molecular Mechanism Controlling Metastasis
Glycosylation alterations are involved in several steps of human cancer pathogenesis. In this issue of Cancer Cell, Agrawal et al. identified the glycosyltransferase FUT8 as a previously unrecognized mediator of melanoma metastasis, establishing core fucosylation as a potential therapeutic target for prevention and treatment of metastatic tumors.The authors acknowledge funding by FEDER, COMPETE and FCT: POCI-01-0145-FEDER-007274 (UID/BIM/04293/2013), POCI-01-0145-FEDER-016585 (PTDC/BBB-EBI/0567/2014), NORTE 2020 (NORTE-01-0145-FEDER-000029), and EU 7th Framework Programme ITN 316929
Methods for estimating the case fatality ratio for a novel, emerging infectious disease.
During the course of an epidemic of a potentially fatal disease, it is important that the case fatality ratio be well estimated. The authors propose a novel method for doing so based on the Kaplan-Meier survival procedure, jointly considering two outcomes (death and recovery), and evaluate its performance by using data from the 2003 epidemic of severe acute respiratory syndrome in Hong Kong, People's Republic of China. They compare this estimate obtained at various points in the epidemic with the case fatality ratio eventually observed; with two commonly quoted, naïve estimates derived from cumulative incidence and mortality statistics at single time points; and with estimates in which a parametric mixture model is used. They demonstrate the importance of patient characteristics regarding outcome by analyzing subgroups defined by age at admission to the hospital
Effects of Gender and Seasonal Variation on the Prevalence of Bacterial Septicaemia Among Young Children in Benin City, Nigeria
Aim: To determine the effects of gender and seasonal variations on the prevalence of bacterial septicaemia among children 5 years and younger, and to identify the bacterial agents responsible for septicaemia and their antibiotic susceptibility profiles. Methods: Blood was collected from 1,724children (967 males and 757 females) aged 1 day to 5 years with clinical signs and symptoms of septicaemia. This study was carried out from 1 January to 31 December 2007 at the University of Benin Teaching Hospital, Benin City, Nigeria. The blood samples were processed to diagnosebacterial septicaemia. Bacterial isolates were identified and susceptibility test was performed using standard techniques. Results: An overall prevalence of 22.10% of confirmed bacterial septicaemia was observed in this study. Generally, gender and seasonal variations did not significantly affect the prevalence of bacterial septicaemia, though females (50.57%) during the dry season had significantly (p < 0.001) higher prevalence than their male counterparts (19.91%). Staphylococcus aureus was thepredominant bacterial isolate causing septicaemia in both seasons, while Citrobacter freundii was the least frequent. Pseudomonas aeruginosa was not recovered during the dry season. Most isolates were susceptible to gentamicin and cefuroxime, but only 1.44% of Staphylococcus aureus strains were susceptible to ceftriaxone. Conclusion: Bacterial septicaemia was observed in 22.1% of children 5 years and younger with clinical signs and symptoms of septicaemia. Seasonal variation did not affect the prevalence. Effect of gender was only noticed in the dry season, where females had a higher prevalence than males. Gentamicin and cefuroxime were the most active antibacterial agents. Rational use of antibiotics is advocated.Key words: Gender, Seasonal variation, Bacterial septicaemi
On the Computational Complexity of Vertex Integrity and Component Order Connectivity
The Weighted Vertex Integrity (wVI) problem takes as input an -vertex
graph , a weight function , and an integer . The
task is to decide if there exists a set such that the weight
of plus the weight of a heaviest component of is at most . Among
other results, we prove that:
(1) wVI is NP-complete on co-comparability graphs, even if each vertex has
weight ;
(2) wVI can be solved in time;
(3) wVI admits a kernel with at most vertices.
Result (1) refutes a conjecture by Ray and Deogun and answers an open
question by Ray et al. It also complements a result by Kratsch et al., stating
that the unweighted version of the problem can be solved in polynomial time on
co-comparability graphs of bounded dimension, provided that an intersection
model of the input graph is given as part of the input.
An instance of the Weighted Component Order Connectivity (wCOC) problem
consists of an -vertex graph , a weight function ,
and two integers and , and the task is to decide if there exists a set
such that the weight of is at most and the weight of
a heaviest component of is at most . In some sense, the wCOC problem
can be seen as a refined version of the wVI problem. We prove, among other
results, that:
(4) wCOC can be solved in time on interval graphs,
while the unweighted version can be solved in time on this graph
class;
(5) wCOC is W[1]-hard on split graphs when parameterized by or by ;
(6) wCOC can be solved in time;
(7) wCOC admits a kernel with at most vertices.
We also show that result (6) is essentially tight by proving that wCOC cannot
be solved in time, unless the ETH fails.Comment: A preliminary version of this paper already appeared in the
conference proceedings of ISAAC 201
Using Bars As Signposts of Galaxy Evolution at High and Low Redshifts
An analysis of the NICMOS Deep Field shows that there is no evidence of a
decline in the bar fraction beyond z~0.7, as previously claimed; both
bandshifting and spatial resolution must be taken into account when evaluating
the evolution of the bar fraction. Two main caveats of this study were a lack
of a proper comparison sample at low redshifts and a larger number of galaxies
at high redshifts. We address these caveats using two new studies. For a proper
local sample, we have analyzed 134 spirals in the near-infrared using 2MASS
(main results presented by Menendez-Delmestre in this volume) which serves as
an ideal anchor for the low-redshift Universe. In addition to measuring the
mean bar properties, we find that bar size is correlated with galaxy size and
brightness, but the bar ellipticity is not correlated with these galaxy
properties. The bar length is not correlated with the bar ellipticity. For
larger high redshift samples we analyze the bar fraction from the 2-square
degree COSMOS ACS survey. We find that the bar fraction at z~0.7 is ~50%,
consistent with our earlier finding of no decline in bar fraction at high
redshifts.Comment: In the proceedings of "Penetrating Bars through Masks of Cosmic Dust:
The Hubble Tuning Fork strikes a New Note
Childhood solid tumours in relation to population mixing around the time of birth
In a retrospective cohort study of 673 787 live births in the Northern Region of England, 1975 - 1994, we investigated whether a higher level of population mixing around birth was a risk factor for solid tumours, by diagnostic group (Hodgkin's disease, brain and spinal tumours, neuroblastoma, other solid tumours), diagnosed during 1975-2001 under age 15 years. Logistic regression was used to relate risk to population mixing, based on (i) all movers and (ii) incomers from outside the region. Both ward and county district level analyses were performed. There was a decreased risk of brain and spinal tumours with increasing population mixing based on incomers from outside the region (OR for trend across three categories = 0.79, 95% CI: 0.66-0.95, P = 0.01 in the ward level analysis). Although this may be because of chance, it is consistent with a role of exposure to infection and immunological response in the aetiology of these tumours. For other tumour groups, there was no consistent evidence of an association between risk and population mixing
Widespread translational control contributes to the regulation of Arabidopsis photomorphogenesis
Environmental light regulates and optimizes plant growth and development. Genomic profiling of polysome-associated mRNA reveals that light stimulates dramatic changes in translational regulation, which contribute more to light-induced gene expression changes than transcriptional regulation
Canalis Sinuosus and radiographic procedures in the region of anterior maxilla
The Canalis Sinuosus (CS) is known as an anatomical variation of anterior superior alveolar nerve being a neurovascular bundle. Frequently, the anterior maxillary region receives surgical interventions of different specialties. The knowledge concerning anatomical structures in this region, is crucial to reach predictable and safe surgical procedures. The overlapping of anatomical structures in conventional imaging examinations have a limit in observing neurovascular canal, such as the CS. Thus, Cone Beam Computed Tomography (CBCT) images may give a great support in preoperative planning, since it allows the three-dimensional reconstruction of the anatomical details of its structures. In this report, the author describes an implant rehabilitation that may have possibly injured the anterior superior alveolar nerve
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On the discovery of K-enhanced and possibly Mg-depleted stars throughout the Milky Way
Stars with unusual elemental abundances offer clues about rare astrophysical
events or nucleosynthetic pathways. Stars with significantly depleted magnesium
and enhanced potassium ([Mg/Fe] 1) have to date only been
found in the massive globular cluster NGC 2419 and, to a lesser extent, NGC
2808. The origin of this abundance signature remains unknown, as does the
reason for its apparent exclusivity to these two globular clusters. Here we
present 112 field stars, identified from 454,180 LAMOST giants, that show
significantly enhanced [K/Fe] and possibly depleted [Mg/Fe] abundance ratios.
Our sample spans a wide range of metallicities (-1.5 < [Fe/H] < 0.3), yet none
show abundance ratios of [K/Fe] or [Mg/Fe] that are as extreme as those
observed in NGC 2419. If confirmed, the identified sample of stars represents
evidence that the nucleosynthetic process producing the anomalous abundances
ratios of [K/Fe] and [Mg/Fe] probably occurs at a wide range of metallicities.
This would suggest that pollution scenarios that are limited to early epochs
(such as Population III supernovae) are an unlikely explanation, although they
cannot be ruled out entirely. This sample is expected to help guide modelling
attempts to explain the origin of the Mg-K abundance signature
PI controller tuning for load disturbance rejection using constrained optimization
© 2016, Springer-Verlag Berlin Heidelberg. In this paper, a simple and effective PI controller tuning method is presented. To take both performance requirements and robustness issues into consideration, the design technique is based on optimization of load disturbance rejection with a constraint either on the gain margin or phase margin. In addition, a simplified form of the resulting tuning formulae is obtained for first order plus dead time models. To demonstrate the ability of the proposed tuning technique in dealing with a wide range of plants, simulation results for several examples, including integrating, non-minimum phase and long dead time models, are provided
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