830 research outputs found
Systematic off-pump coronary artery revascularization in multivessel disease: Experience of three hundred cases
AbstractObjective: We sought to report our recent experience with off-pump coronary artery revascularization in multivessel disease. Methods: Between October 1996 and December 1998, 300 off-pump beating heart operations were performed at the Montreal Heart Institute by a single surgeon, representing 94% of all procedures undertaken during this same time frame (97% for 1998). This cohort of patients was compared with 1870 patients operated on with cardiopulmonary bypass from 1995 to 1996. Results: Mean age, sex distribution, and preoperative risk factors were comparable for the two groups. On average, 2.92 ± 0.8 and 2.84 ± 0.6 grafts per patient were completed in the beating heart and cardiopulmonary bypass groups, respectively. A majority of patients (70%) had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart “verticalization.” Ischemic time was shorter in the beating heart group (29.8 ± 0.9 vs 45 ± 0.4 minutes, P < .05). Similarly, the need for transfusion was significantly less in the beating heart group (beating heart operations, 34%; cardiopulmonary bypass, 66%; P < .005). Reduced use of postoperative intra-aortic counterpulsation, as well as a lower rise in creatine kinase MB isoenzyme, was observed in the beating heart group. Operative mortality rates (beating heart operations, 1.3%; cardiopulmonary bypass, 2%) and perioperative myocardial infarction (beating heart operations, 3.6%; cardiopulmonary bypass, 4.2%) were comparable for the two groups. Conclusion: In a majority of patients, off-pump complete coronary artery revascularization is an acceptable alternative to conventional operations, yielding good results given progressive experience, rigorous technique, and adequate coronary artery stabilization. (J Thorac Cardiovasc Surg 2000;119:221-9
A cost effective AFM setup, combining interferometry and FPGA
International audienceAtomic force microscopes (AFM) provide high resolution images of surfaces. In this paper, we focus on an interferometry method for estimation of deflections in arrays of cantilever in quasi-static regime. We propose a novel complete solution with a least square based algorithm to determine interference fringe phases and its optimized FPGA implementation. Simulations and real tests show very good results and open perspectives for real-time estimation and control of cantilever arrays in the dynamic regime
Fast Autofocusing using Tiny Transformer Networks for Digital Holographic Microscopy
The numerical wavefront backpropagation principle of digital holography
confers unique extended focus capabilities, without mechanical displacements
along z-axis. However, the determination of the correct focusing distance is a
non-trivial and time consuming issue. A deep learning (DL) solution is proposed
to cast the autofocusing as a regression problem and tested over both
experimental and simulated holograms. Single wavelength digital holograms were
recorded by a Digital Holographic Microscope (DHM) with a 10
microscope objective from a patterned target moving in 3D over an axial range
of 92 m. Tiny DL models are proposed and compared such as a tiny Vision
Transformer (TViT), tiny VGG16 (TVGG) and a tiny Swin-Transfomer (TSwinT). The
experiments show that the predicted focusing distance is
accurately inferred with an accuracy of 1.2 m in average in comparison
with the DHM depth of field of 15 m. Numerical simulations show that all
tiny models give the with an error below 0.3 m. Such
a prospect would significantly improve the current capabilities of computer
vision position sensing in applications such as 3D microscopy for life sciences
or micro-robotics. Moreover, all models reach state of the art inference time
on CPU, less than 25 ms per inference
Perfluorooctyl substituted triphenylphosphites as ligands for hydroformylation of higher olefins in fluorocarbon/hydrocarbon biphasic medium
Disturbance cues in freshwater prey fishes: Does urea function as an ‘early warning cue’in juvenile convict cichlids and rainbow trout?
Freshwater vertebrate and invertebrate prey species commonly rely on chemosensory information, including non-injury released disturbance cues, to assess local predation threats. We conducted laboratory studies to (1) determine if urea can function as a disturbance cue in juvenile convict cichlids and rainbow trout and (2) determine if the background level of urea influences the behavioral response to a subsequent pulse of urea (‘background noise’ hypothesis). In the first series of trials, juvenile cichlids and trout were exposed to urea at varying concentrations (0 to 0.5 mg L-1 for cichlids and 0 to 1.0 mg L-1 for trout). Our results suggest that both cichilds and trout exhibited functionally similar responses to urea and conspecific disturbance cues and that increasing the concentration of urea results in an increase intensity of antipredator behaviour. In the second series of trials, we pre-exposed cichlids or trout to intermediate or high concentrations of urea (or a distilled water control) and then tested for the response to a second pulse of urea at at intermediate or high concentrations (versus a distilled water control). Our results demonstrate that pre-exposure to urea reduces or eliminates the response to a second pulse of urea, supporting the background noise hypothesis. Together, our results suggest that pulses of urea, released by disturbed or stressed individuals, may function as an early warning signal in freshwater prey species [Current Zoology 58 (2): 250–259 , 2012]
The interaction between the measles virus nucleoprotein and the Interferon Regulator Factor 3 relies on a specific cellular environment
<p>Abstract</p> <p>Background</p> <p>The genome of measles virus consists of a non-segmented single-stranded RNA molecule of negative polarity, which is encapsidated by the viral nucleoprotein (N) within a helical nucleocapsid. The N protein possesses an intrinsically disordered C-terminal domain (aa 401–525, N<sub>TAIL</sub>) that is exposed at the surface of the viral nucleopcapsid. Thanks to its flexible nature, N<sub>TAIL </sub>interacts with several viral and cellular partners. Among these latter, the Interferon Regulator Factor 3 (IRF-3) has been reported to interact with N, with the interaction having been mapped to the regulatory domain of IRF-3 and to N<sub>TAIL</sub>. This interaction was described to lead to the phosphorylation-dependent activation of IRF-3, and to the ensuing activation of the pro-immune cytokine RANTES gene.</p> <p>Results</p> <p>After confirming the reciprocal ability of IRF-3 and N to be co-immunoprecipitated in 293T cells, we thoroughly investigated the N<sub>TAIL</sub>-IRF-3 interaction using a recombinant, monomeric form of the regulatory domain of IRF-3. Using a large panel of spectroscopic approaches, including circular dichroism, fluorescence spectroscopy, nuclear magnetic resonance and electron paramagnetic resonance spectroscopy, we failed to detect any direct interaction between IRF-3 and either full-length N or N<sub>TAIL </sub>under conditions where these latter interact with the C-terminal X domain of the viral phosphoprotein. Furthermore, such interaction was neither detected in <it>E. coli </it>nor in a yeast two hybrid assay.</p> <p>Conclusion</p> <p>Altogether, these data support the requirement for a specific cellular environment, such as that provided by 293T human cells, for the N<sub>TAIL</sub>-IRF-3 interaction to occur. This dependence from a specific cellular context likely reflects the requirement for a human or mammalian cellular co-factor.</p
Modeling, Filtering and Optimization for AFM Arrays
We will present new tools and results developed for Arrays of Microsystems and especially for AFM array design.For modeling,we developed a two-scale model of cantilever arrays in elastodynamics.A robust optimization toolbox is interfaced to aid for design before fabrication.Two real-time computation methods for filtering and control of the coupled cantilevers are studied.One is based on functions of operators and the Cauchy integral formula.It may be realized with PNR.The second one relies to diffusive realization to be implemented in a FPGA.Displacement measurement is done by interferometry
Metabolism of no-carrier-added 2-[18F]fluoro-L-tyrosine in rats
Background: Several fluorine-18 labelled fluoroamino acids have been evaluated as tracers for the quantitative assessment of cerebral protein synthesis in vivo by positron emission tomography (PET). Among these, 2-[18F]fluoro-L-tyrosine (2-[18F]Tyr) has been studied in mice at a low specific activity. Its incorporation into proteins is fast and metabolism via other pathways is limited. The present in vivo study was carried out in normal awake rats using no-carrier-added 2-[18F]Tyr. Under normal physiological conditions, we have studied the incorporation into proteins and the metabolism of the tracer in different brain areas.
Methods: No-carrier-added 2-[18F]Tyr was administered to awake rats equipped with chronic
arterial and venous catheters. The time course of the plasma activity was studied by arterial blood sampling. The biodistribution of the activity in the main organs was studied at the end of the
experiment. The distribution of radioactive species in plasma and brain regions was studied by
acidic precipitation of the proteins and HPLC analysis of the supernatant.
Results: The absolute uptake of radioactivity in brain regions was homogenous. In awake rats, nocarrier-added 2-[18F]Tyr exhibits a fast and almost quantitative incorporation into the proteins
fractions of cerebellum and cortex. In striatum, this incorporation into proteins and the unchanged
fraction of the tracer detected by HPLC could be lower than in other brain regions.
Conclusion: This study confirms the potential of 2-[18F]fluoro-L-tyrosine as a tracer for the
assessment of the rate of protein synthesis by positron emission tomography. The observed
metabolism suggests a need for a correction for the appearance of metabolites, at least in plasma
QUARITE (quality of care, risk management and technology in obstetrics): a cluster-randomized trial of a multifaceted intervention to improve emergency obstetric care in Senegal and Mali
<p>Abstract</p> <p>Background</p> <p>Maternal and perinatal mortality are major problems for which progress in sub-Saharan Africa has been inadequate, even though childbirth services are available, even in the poorest countries. Reducing them is the aim of two of the main Millennium Development Goals. Many initiatives have been undertaken to remedy this situation, such as the Advances in Labour and Risk Management (ALARM) International Program, whose purpose is to improve the quality of obstetric services in low-income countries. However, few interventions have been evaluated, in this context, using rigorous methods for analyzing effectiveness in terms of health outcomes. The objective of this trial is to evaluate the effectiveness of the ALARM International Program (AIP) in reducing maternal mortality in referral hospitals in Senegal and Mali. Secondary goals include evaluation of the relationships between effectiveness and resource availability, service organization, medical practices, and satisfaction among health personnel.</p> <p>Methods/Design</p> <p>This is an international, multi-centre, controlled cluster-randomized trial of a complex intervention. The intervention is based on the concept of evidence-based practice and on a combination of two approaches aimed at improving the performance of health personnel: 1) Educational outreach visits; and 2) the implementation of facility-based maternal death reviews.</p> <p>The unit of intervention is the public health facility equipped with a functional operating room. On the basis of consent provided by hospital authorities, 46 centres out of 49 eligible were selected in Mali and Senegal. Using randomization stratified by country and by level of care, 23 centres will be allocated to the intervention group and 23 to the control group. The intervention will last two years. It will be preceded by a pre-intervention one-year period for baseline data collection. A continuous clinical data collection system has been set up in all participating centres. This, along with the inventory of resources and the satisfaction surveys administered to the health personnel, will allow us to measure results before, during, and after the intervention. The overall rate of maternal mortality measured in hospitals during the post-intervention period (Year 4) is the primary outcome. The evaluation will also include cost-effectiveness.</p> <p>Trial Registration</p> <p>The QUARITE trial is registered on the Current Controlled Trials website under the number ISRCTN46950658 <url>http://www.controlled-trials.com/</url>.</p
A genomic and transcriptomic approach for a differential diagnosis between primary and secondary ovarian carcinomas in patients with a previous history of breast cancer
<p>Abstract</p> <p>Background</p> <p>The distinction between primary and secondary ovarian tumors may be challenging for pathologists. The purpose of the present work was to develop genomic and transcriptomic tools to further refine the pathological diagnosis of ovarian tumors after a previous history of breast cancer.</p> <p>Methods</p> <p>Sixteen paired breast-ovary tumors from patients with a former diagnosis of breast cancer were collected. The genomic profiles of paired tumors were analyzed using the Affymetrix GeneChip<sup>® </sup>Mapping 50 K Xba Array or Genome-Wide Human SNP Array 6.0 (for one pair), and the data were normalized with ITALICS (ITerative and Alternative normaLIzation and Copy number calling for affymetrix Snp arrays) algorithm or Partek Genomic Suite, respectively. The transcriptome of paired samples was analyzed using Affymetrix GeneChip<sup>® </sup>Human Genome U133 Plus 2.0 Arrays, and the data were normalized with gc-Robust Multi-array Average (gcRMA) algorithm. A hierarchical clustering of these samples was performed, combined with a dataset of well-identified primary and secondary ovarian tumors.</p> <p>Results</p> <p>In 12 of the 16 paired tumors analyzed, the comparison of genomic profiles confirmed the pathological diagnosis of primary ovarian tumor (n = 5) or metastasis of breast cancer (n = 7). Among four cases with uncertain pathological diagnosis, genomic profiles were clearly distinct between the ovarian and breast tumors in two pairs, thus indicating primary ovarian carcinomas, and showed common patterns in the two others, indicating metastases from breast cancer. In all pairs, the result of the transcriptomic analysis was concordant with that of the genomic analysis.</p> <p>Conclusions</p> <p>In patients with ovarian carcinoma and a previous history of breast cancer, SNP array analysis can be used to distinguish primary and secondary ovarian tumors. Transcriptomic analysis may be used when primary breast tissue specimen is not available.</p
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