3,726 research outputs found
Structural and functional alterations of the tracheobronchial tree after left upper pulmonary lobectomy for lung cancer
© 2019 The Author(s). Background: Pulmonary lobectomy has been a well-established curative treatment method for localized lung cancer. After left upper pulmonary lobectomy, the upward displacement of remaining lower lobe causes the distortion or kink of bronchus, which is associated with intractable cough and breathless. However, the quantitative study on structural and functional alterations of the tracheobronchial tree after lobectomy has not been reported. We sought to investigate these alterations using CT imaging analysis and computational fluid dynamics (CFD) method. Methods: Both preoperative and postoperative CT images of 18 patients who underwent left upper pulmonary lobectomy are collected. After the tracheobronchial tree models are extracted, the angles between trachea and bronchi, the surface area and volume of the tree, and the cross-sectional area of left lower lobar bronchus are investigated. CFD method is further used to describe the airflow characteristics by the wall pressure, airflow velocity, lobar flow rate, etc. Results: It is found that the angle between the trachea and the right main bronchus increases after operation, but the angle with the left main bronchus decreases. No significant alteration is observed for the surface area or volume of the tree between pre-operation and post-operation. After left upper pulmonary lobectomy, the cross-sectional area of left lower lobar bronchus is reduced for most of the patients (15/18) by 15-75%, especially for 4 patients by more than 50%. The wall pressure, airflow velocity and pressure drop significantly increase after the operation. The flow rate to the right lung increases significantly by 2-30% (but there is no significant difference between each lobe), and the flow rate to the left lung drops accordingly. Many vortices are found in various places with severe distortions. Conclusions: The favorable and unfavorable adaptive alterations of tracheobronchial tree will occur after left upper pulmonary lobectomy, and these alterations can be clarified through CT imaging and CFD analysis. The severe distortions at left lower lobar bronchus might exacerbate postoperative shortness of breath
Effect of vitamin B 12 and n-3 polyunsaturated fatty acids on plasma homocysteine, ferritin, C-reaction protein, and other cardiovascular risk factors: a randomized controlled trial
Objectives: Vitamin B 12 and n-3 polyunsaturated fatty acids (PUFA) decrease blood homocysteine (Hcy) concentrations. However, the combined effect of these nutrients on Hcy and ferritin, and C-reactive protein is limited and inconclusive. The objective was to examine the synergistic effect of vitamin B 12 in combination of n-3 PUFA on plasma Hcy, ferritin, and other biochemical markers. Methods: In a randomized controlled trial, thirty eligible subjects were randomly divided into three groups, and assigned to receive 1000 μg of vitamin B 12 , 2 g fish oil, or 1000 μg vitamin B 12 and 2 g fish oil, respectively, for 8 weeks. Plasma phospholipids (PL) fatty acids and biochemical markers were determined. This study was registered under ClinicalTrials.gov Identifier: NCT01762072. Results: Plasma PL 20:5n-3, 22:6n-3 and n-3 PUFA was increased after 4 and 8 week supplementation of fish oil, and vitamin B 12 +fish oil. Plasma concentrations of triacylglycerol, uric acid, C-reactive protein, and ferritin were significantly decreased after 4 and 8 week supplementation of fish oil, and vitamin B 12 +fish oil. In all groups, significant changes in plasma Hcy were observed during the study period. Vitamin B 12 , fish oil, and vitamin B 12 +fish oil supplementation lowered plasma Hcy concentrations by 22%, 19%, and 39%, respectively. Conclusions: The combination of vitamin B 12 and fish oil has a synergistic effect on lowering plasma concentrations of Hcy
PKCε-dependent potentiation of TTX-resistant Nav1.8 current by neurokinin-1 receptor activation in rat dorsal root ganglion neurons
<p>Abstract</p> <p>Background</p> <p>Substance P (SP), which mainly exists in a subtype of small-diameter dorsal root ganglion (DRG) neurons, is an important signal molecule in pain processing in the spinal cord. Our previous results have proved the expression of SP receptor neurokinin-1 (NK-1) on DRG neurons and its interaction with transient receptor potential vanilloid 1 (TRPV1) receptor.</p> <p>Results</p> <p>In this study we investigated the effect of NK-1 receptor agonist on Na<sub>v</sub>1.8, a tetrodotoxin (TTX)-resistant sodium channel, in rat small-diameter DRG neurons employing whole-cell patch clamp recordings. NK-1 agonist [Sar<sup>9</sup>, Met(O<sub>2</sub>)<sup>11</sup>]-substance P (Sar-SP) significantly enhanced the Na<sub>v</sub>1.8 currents in a subgroup of small-diameter DRG neurons under both the normal and inflammatory situation, and the enhancement was blocked by NK-1 antagonist Win51708 and protein kinase C (PKC) inhibitor bisindolylmaleimide (BIM), but not the protein kinase A (PKA) inhibitor H89. In particular, the inhibitor of PKCε, a PKC isoform, completely blocked this effect. Under current clamp model, Sar-SP reduced the amount of current required to evoke action potentials and increased the firing rate in a subgroup of DRG neurons.</p> <p>Conclusion</p> <p>These data suggest that activation of NK-1 receptor potentiates Na<sub>v</sub>1.8 sodium current via PKCε-dependent signaling pathway, probably participating in the generation of inflammatory hyperalgesia.</p
A boosting method for maximizing the partial area under the ROC curve
<p>Abstract</p> <p>Background</p> <p>The receiver operating characteristic (ROC) curve is a fundamental tool to assess the discriminant performance for not only a single marker but also a score function combining multiple markers. The area under the ROC curve (AUC) for a score function measures the intrinsic ability for the score function to discriminate between the controls and cases. Recently, the partial AUC (pAUC) has been paid more attention than the AUC, because a suitable range of the false positive rate can be focused according to various clinical situations. However, existing pAUC-based methods only handle a few markers and do not take nonlinear combination of markers into consideration.</p> <p>Results</p> <p>We have developed a new statistical method that focuses on the pAUC based on a boosting technique. The markers are combined componentially for maximizing the pAUC in the boosting algorithm using natural cubic splines or decision stumps (single-level decision trees), according to the values of markers (continuous or discrete). We show that the resulting score plots are useful for understanding how each marker is associated with the outcome variable. We compare the performance of the proposed boosting method with those of other existing methods, and demonstrate the utility using real data sets. As a result, we have much better discrimination performances in the sense of the pAUC in both simulation studies and real data analysis.</p> <p>Conclusions</p> <p>The proposed method addresses how to combine the markers after a pAUC-based filtering procedure in high dimensional setting. Hence, it provides a consistent way of analyzing data based on the pAUC from maker selection to marker combination for discrimination problems. The method can capture not only linear but also nonlinear association between the outcome variable and the markers, about which the nonlinearity is known to be necessary in general for the maximization of the pAUC. The method also puts importance on the accuracy of classification performance as well as interpretability of the association, by offering simple and smooth resultant score plots for each marker.</p
The space group classification of topological band insulators
Topological band insulators (TBIs) are bulk insulating materials which
feature topologically protected metallic states on their boundary. The existing
classification departs from time-reversal symmetry, but the role of the crystal
lattice symmetries in the physics of these topological states remained elusive.
Here we provide the classification of TBIs protected not only by time-reversal,
but also by crystalline symmetries. We find three broad classes of topological
states: (a) Gamma-states robust against general time-reversal invariant
perturbations; (b) Translationally-active states protected from elastic
scattering, but susceptible to topological crystalline disorder; (c) Valley
topological insulators sensitive to the effects of non-topological and
crystalline disorder. These three classes give rise to 18 different
two-dimensional, and, at least 70 three-dimensional TBIs, opening up a route
for the systematic search for new types of TBIs.Comment: Accepted in Nature Physic
Physical mapping integrated with syntenic analysis to characterize the gene space of the long arm of wheat chromosome 1A
Background: Bread wheat (Triticum aestivum L.) is one of the most important crops worldwide and its production faces pressing challenges, the solution of which demands genome information. However, the large, highly repetitive hexaploid wheat genome has been considered intractable to standard sequencing approaches. Therefore the International Wheat Genome Sequencing Consortium (IWGSC) proposes to map and sequence the genome on a chromosome-by-chromosome basis.
Methodology/Principal Findings: We have constructed a physical map of the long arm of bread wheat chromosome 1A using chromosome-specific BAC libraries by High Information Content Fingerprinting (HICF). Two alternative methods (FPC and LTC) were used to assemble the fingerprints into a high-resolution physical map of the chromosome arm. A total of 365 molecular markers were added to the map, in addition to 1122 putative unique transcripts that were identified by microarray hybridization. The final map consists of 1180 FPC based or 583 LTC based contigs. Conclusions/Significance: The physical map presented here marks an important step forward in mapping of hexaploid bread wheat. The map is orders of magnitude more detailed than previously available maps of this chromosome, and the assignment of over a thousand putative expressed gene sequences to specific map locations will greatly assist future functional studies. This map will be an essential tool for future sequencing of and positional cloning within chromosome 1A
The conserved C-terminus of the PcrA/UvrD helicase interacts directly with RNA polymerase
Copyright: © 2013 Gwynn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a Wellcome Trust project grant to MD (Reference: 077368), an ERC starting grant to MD (Acronym: SM-DNA-REPAIR) and a BBSRC project grant to PM, NS and MD (Reference: BB/I003142/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
CD20 and CD19 targeted vectors induce minimal activation of resting B lymphocytes
B lymphocytes are an important cell population of the immune system. However, until recently it was not possible to transduce resting B lymphocytes with retro- or lentiviral vectors, making them unsusceptible for genetic manipulations by these vectors. Lately, we demonstrated that lentiviral vectors pseudotyped with modified measles virus (MV) glycoproteins hemagglutinin, responsible for receptor recognition, and fusion protein were able to overcome this transduction block. They use either the natural MV receptors, CD46 and signaling lymphocyte activation molecule (SLAM), for cell entry (MV-LV) or the vector particles were further modified to selectively enter via the CD20 molecule, which is exclusively expressed on B lymphocytes (CD20-LV). It has been shown previously that transduction by MV-LV does not induce B lymphocyte activation. However, if this is also true for CD20-LV is still unknown. Here, we generated a vector specific for another B lymphocyte marker, CD19, and compared its ability to transduce resting B lymphocytes with CD20-LV. The vector (CD19ds-LV) was able to stably transduce unstimulated B lymphocytes, albeit with a reduced efficiency of about 10% compared to CD20-LV, which transduced about 30% of the cells. Since CD20 as well as CD19 are closely linked to the B lymphocyte activation pathway, we investigated if engagement of CD20 or CD19 molecules by the vector particles induces activating stimuli in resting B lymphocytes. Although, activation of B lymphocytes often involves calcium influx, we did not detect elevated calcium levels. However, the activation marker CD71 was substantially up-regulated upon CD20-LV transduction and most importantly, B lymphocytes transduced with CD20-LV or CD19ds-LV entered the G1b phase of cell cycle, whereas untransduced or MV-LV transduced B lymphocytes remained in G0. Hence, CD20 and CD19 targeting vectors induce activating stimuli in resting B lymphocytes, which most likely renders them susceptible for lentiviral vector transduction
Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials
Recent progress in understanding the topological properties of condensed
matter has led to the discovery of time-reversal invariant topological
insulators. Because of limitations imposed by nature, topologically non-trivial
electronic order seems to be uncommon except in small-band-gap semiconductors
with strong spin-orbit interactions. In this Article we show that artificial
electromagnetic structures, known as metamaterials, provide an attractive
platform for designing photonic analogues of topological insulators. We
demonstrate that a judicious choice of the metamaterial parameters can create
photonic phases that support a pair of helical edge states, and that these edge
states enable one-way photonic transport that is robust against disorder.Comment: 13 pages, 3 figure
Combinatorial CRISPR-Cas9 screens for de novo mapping of genetic interactions.
We developed a systematic approach to map human genetic networks by combinatorial CRISPR-Cas9 perturbations coupled to robust analysis of growth kinetics. We targeted all pairs of 73 cancer genes with dual guide RNAs in three cell lines, comprising 141,912 tests of interaction. Numerous therapeutically relevant interactions were identified, and these patterns replicated with combinatorial drugs at 75% precision. From these results, we anticipate that cellular context will be critical to synthetic-lethal therapies
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