3,257 research outputs found
Scientometric Analysis and Density-Equalizing Mapping
Pulmonary hypertension (PH) is characterized by the increase of the mean
pulmonary arterial pressure in the lung circulation. Despite the large number
of experimental and clinical studies conducted on pulmonary hypertension,
there is no comprehensive work that analyzed the global research activity on
PH so far. We retrieved the bibliometric data of the publications on pulmonary
hypertension for two periods from the Web of science database. Here, we set
the first investigation period from 1900 to 2007 (t1) due to the cited half
life of articles and the relating difficulties to interpret the citation
parameters. The second evaluation period (t2) covers the time interval from
2008 onwards including the year 2015. The data were analyzed and processed to
density-equalizing maps using the NewQIS platform. A total number of 18,986
publications were identified in t1 that come from 85 countries. The US
published the highest number of publications (n = 7,290), followed by the UK,
Germany, Japan and France. In t2 19,676 items could be found worked out by 130
countries. The raking started just the same with the USA as most publishing
nation with 7,127 publications on PH, followed by the UK and Germany. Japan
fell back on 6th place, whereas China came into view on the 5th position.
Analyzing the average citation rate as a parameter for research quality,
Mexico reached the highest value in t1 and Ireland in t2. While, the country
specific h-index underlined the leading position of the US research in both
evaluation periods again. The average number of international collaboration
items was expanding from none in 1978 to 530 items in 2015 with the USA as the
country with the highest number of collaboration articles. The present study
is the first large scale density-equalizing mapping and scientometric analysis
of global PH research activity. Our data draw a sketch of the global research
architecture in this field, indicating a need for specific research programs
in countries with a lower human development index
Deep-Learning-Based Segmentation of the Shoulder from MRI with Inference Accuracy Prediction
Three-dimensional (3D)-image-based anatomical analysis of rotator cuff tear patients has been proposed as a way to improve repair prognosis analysis to reduce the incidence of postoperative retear. However, for application in clinics, an efficient and robust method for the segmentation of anatomy from MRI is required. We present the use of a deep learning network for automatic segmentation of the humerus, scapula, and rotator cuff muscles with integrated automatic result verification. Trained on N = 111 and tested on N = 60 diagnostic T1-weighted MRI of 76 rotator cuff tear patients acquired from 19 centers, a nnU-Net segmented the anatomy with an average Dice coefficient of 0.91 Âą 0.06. For the automatic identification of inaccurate segmentations during the inference procedure, the nnU-Net framework was adapted to allow for the estimation of label-specific network uncertainty directly from its subnetworks. The average Dice coefficient of segmentation results from the subnetworks identified labels requiring segmentation correction with an average sensitivity of 1.0 and a specificity of 0.94. The presented automatic methods facilitate the use of 3D diagnosis in clinical routine by eliminating the need for time-consuming manual segmentation and slice-by-slice segmentation verification
Chandra Observations of the Interacting NGC 4410 Galaxy Group
We present high resolution X-ray imaging data from the ACIS-S instrument on
the Chandra telescope of the nearby interacting galaxy group NGC 4410. Four
galaxies in the inner portion of this group are clearly detected by Chandra,
including the peculiar low luminosity radio galaxy NGC 4410A. In addition to a
nuclear point source, NGC 4410A contains diffuse X-ray emission, including an
X-ray ridge extending out to about 12" (6 kpc) to the northwest of the nucleus.
This ridge is coincident with an arc of optical emission-line gas, which has
previously been shown to have optical line ratios consistent with shock
ionization. This structure may be due to an expanding superbubble of hot gas
caused by supernovae and stellar winds or by the active nucleus. The Chandra
observations also show four or five possible compact ultra-luminous X-ray (ULX)
sources (L(x) >= 10^39 erg/s) associated with NGC 4410A. At least one of these
candidate ULXs appears to have a radio counterpart, suggesting that it may be
due to an X-ray binary with a stellar-mass black hole, rather than an
intermediate mass black hole. In addition, a faint diffuse intragroup X-ray
component has been detected between the galaxies (L(x) ~ 10^41 erg/s). This
supports the hypothesis that the NGC 4410 group is in the process of evolving
via mergers from a spiral-dominated group (which typically have no
X-ray-emitting intragroup gas) to an elliptical-dominated group (which often
have a substantial intragroup medium).Comment: 27 pages, 14 figures; Accepted by Astronomical Journal; color images
at http://www.etsu.edu/physics/bsmith/research/n4410.htm
Towards the creation of decellularized organ constructs using irreversible electroporation and active mechanical perfusion
<p>Abstract</p> <p>Background</p> <p>Despite advances in transplant surgery and general medicine, the number of patients awaiting transplant organs continues to grow, while the supply of organs does not. This work outlines a method of organ decellularization using non-thermal irreversible electroporation (N-TIRE) which, in combination with reseeding, may help supplement the supply of organs for transplant.</p> <p>Methods</p> <p>In our study, brief but intense electric pulses were applied to porcine livers while under active low temperature cardio-emulation perfusion. Histological analysis and lesion measurements were used to determine the effects of the pulses in decellularizing the livers as a first step towards the development of extracellular scaffolds that may be used with stem cell reseeding. A dynamic conductivity numerical model was developed to simulate the treatment parameters used and determine an irreversible electroporation threshold.</p> <p>Results</p> <p>Ninety-nine individual 1000 V/cm 100-Îźs square pulses with repetition rates between 0.25 and 4 Hz were found to produce a lesion within 24 hours post-treatment. The livers maintained intact bile ducts and vascular structures while demonstrating hepatocytic cord disruption and cell delamination from cord basal laminae after 24 hours of perfusion. A numerical model found an electric field threshold of 423 V/cm under specific experimental conditions, which may be used in the future to plan treatments for the decellularization of entire organs. Analysis of the pulse repetition rate shows that the largest treated area and the lowest interstitial density score was achieved for a pulse frequency of 1 Hz. After 24 hours of perfusion, a maximum density score reduction of 58.5 percent had been achieved.</p> <p>Conclusions</p> <p>This method is the first effort towards creating decellularized tissue scaffolds that could be used for organ transplantation using N-TIRE. In addition, it provides a versatile platform to study the effects of pulse parameters such as pulse length, repetition rate, and field strength on whole organ structures.</p
Sequential quasi-Monte Carlo: Introduction for Non-Experts, Dimension Reduction, Application to Partly Observed Diffusion Processes
SMC (Sequential Monte Carlo) is a class of Monte Carlo algorithms for
filtering and related sequential problems. Gerber and Chopin (2015) introduced
SQMC (Sequential quasi-Monte Carlo), a QMC version of SMC. This paper has two
objectives: (a) to introduce Sequential Monte Carlo to the QMC community, whose
members are usually less familiar with state-space models and particle
filtering; (b) to extend SQMC to the filtering of continuous-time state-space
models, where the latent process is a diffusion. A recurring point in the paper
will be the notion of dimension reduction, that is how to implement SQMC in
such a way that it provides good performance despite the high dimension of the
problem.Comment: To be published in the proceedings of MCMQMC 201
Central nervous system tumors in children under 5 years of age: a report on treatment burden, survival and long-term outcomes
PURPOSE
The challenges of treating central nervous system (CNS) tumors in young children are many. These include age-specific tumor characteristics, limited treatment options, and susceptibility of the developing CNS to cytotoxic therapy. The aim of this study was to analyze the long-term survival, health-related, and educational/occupational outcomes of this vulnerable patient population.
METHODS
Retrospective study of 128 children diagnosed with a CNS tumor under 5Â years of age at a single center in Switzerland between 1990 and 2019.
RESULTS
Median age at diagnosis was 1.81Â years [IQR, 0.98-3.17]. Median follow-up time of surviving patients was 8.39Â years [range, 0.74-23.65]. The main tumor subtypes were pediatric low-grade glioma (36%), pediatric high-grade glioma (11%), ependymoma (16%), medulloblastoma (11%), other embryonal tumors (7%), germ cell tumors (3%), choroid plexus tumors (6%), and others (9%). The 5-year overall survival (OS) was 78.8% (95% CI, 71.8-86.4%) for the whole cohort. Eighty-seven percent of survivorsâ>â5Â years had any tumor- or treatment-related sequelae with 61% neurological complications, 30% endocrine sequelae, 17% hearing impairment, and 56% visual impairment at last follow-up. Most patients (72%) attended regular school or worked in a skilled job at last follow-up.
CONCLUSION
Young children diagnosed with a CNS tumor experience a range of complications after treatment, many of which are long-lasting and potentially debilitating. Our findings highlight the vulnerabilities of this population, the need for long-term support and strategies for rehabilitation, specifically tailored for young children
Correction to: Central nervous system tumors in children under 5 years of age: a report on treatment burden, survival and long-term outcomes
PURPOSE: The challenges of treating central nervous system (CNS) tumors in young children are many. These include age-specific tumor characteristics, limited treatment options, and susceptibility of the developing CNS to cytotoxic therapy. The aim of this study was to analyze the long-term survival, health-related, and educational/occupational outcomes of this vulnerable patient population. METHODS: Retrospective study of 128 children diagnosed with a CNS tumor under 5Â years of age at a single center in Switzerland between 1990 and 2019. RESULTS: Median age at diagnosis was 1.81Â years [IQR, 0.98â3.17]. Median follow-up time of surviving patients was 8.39Â years [range, 0.74â23.65]. The main tumor subtypes were pediatric low-grade glioma (36%), pediatric high-grade glioma (11%), ependymoma (16%), medulloblastoma (11%), other embryonal tumors (7%), germ cell tumors (3%), choroid plexus tumors (6%), and others (9%). The 5-year overall survival (OS) was 78.8% (95% CI, 71.8â86.4%) for the whole cohort. Eighty-seven percent of survivorsâ>â5Â years had any tumor- or treatment-related sequelae with 61% neurological complications, 30% endocrine sequelae, 17% hearing impairment, and 56% visual impairment at last follow-up. Most patients (72%) attended regular school or worked in a skilled job at last follow-up. CONCLUSION: Young children diagnosed with a CNS tumor experience a range of complications after treatment, many of which are long-lasting and potentially debilitating. Our findings highlight the vulnerabilities of this population, the need for long-term support and strategies for rehabilitation, specifically tailored for young children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11060-022-03963-3
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