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PubMed2001

A linear relation between the compressibility and density of blood.

By considering the blood as a mixture of ultrafiltrate and protein concentrate, the additive nature of compressibility and density from the components is utilized to deduce a linear relation between the compressibility and density for blood. This deduction also indicates that the intercept and slope of the linear relation are independent of the hematocrit, plasma protein concentration, and hemoglobin concentration of red blood cells. To verify experimentally this linear relation, saline and plasma dilutions on porcine or canine blood flowing in an extracorporeal circuit were carried out. The hematocrit of the experiments ranges from 0% to 55% and the plasma protein concentration ranges from 10 to 90 g/l. A resonance device in the circuit measured the density rhob of blood at 37 degrees C and an ultrasound system measured the sound velocity cb. The range of density is from 1,010 to 1,060 g/l and that of sound velocity is from 1,530 to 1,580 m/s. The linear relation that best fits the data of compressibility [computed as (rhob cb(2))-1] and density has a correlation coefficient of 0.9978. The linear relation is found to fit well the dependence of compressibility on density derived from the sound velocity data of human, horse, and porcine blood in the literature.

Animals↗
PubMed1999

Wavelet image compression--the quadtree coding approach.

Perfect reconstruction, quality scalability, and region-of-interest coding are basic features needed for the image compression schemes used in telemedicine applications. This paper proposes a new wavelet-based embedded compression technique that efficiently exploits the intraband dependencies and uses a quadtree-based approach to encode the significance maps. The algorithm produces a losslessly compressed embedded data stream, supports quality scalability, and permits region-of-interest coding. Moreover, experimental results obtained on various images show that the proposed algorithm provides competitive lossless/lossy compression results. The proposed technique is well suited for telemedicine applications that require fast interactive handling of large image sets, over networks with limited and/or variable bandwidth.

Algorithms↗
PubMed2002

[ECG signal compression based on best basis of wavelet packets].

The paper reports a kind of new compression method of ECG signal. The method is realized by means of wavelet packets transform based on best basis performed by Shanon-Weaker entropy criterion. The result of simulation shows that this is an efficient compression method characterized by larger compression ratio and less loss, and the original signal can be recovered well.

Algorithms↗
PubMedDate not supplied

External pneumatic intermittent compression for treatment of dependent pregnancy edema.

A portable external pneumatic intermittent compression (EPIC) device has been successful in reducing peripheral edema. This study explored the effectiveness of EPIC for treating dependent pregnancy edema. In the study, 42 healthy pregnant women received EPIC for 30 minutes at 40 torr while in the left lateral recumbent position: Group One with mid-thigh boots, and Group Two with below-knee boots. Prior to compression, descriptive data were gathered, leg circumference measurements made, and surface skin temperatures recorded for three sites per leg. Vital signs were taken and pedal edema subjectively indexed. Following compression, circumferences, skin temperatures, vital signs, and edema indices were rerecorded. Three volumes were calculated for each leg using a mathematical model of leg segments as conical frustum units. Mean volume reductions for each leg were significant. The mid-thigh-length boots produced greater mean volume decreases. The volume decrease for calf, lower leg, and foot frustum units were significant. EPIC holds promise as a useful treatment for dependent pregnancy edema.

Adolescent↗
PubMed1993

Compressive properties of the cartilaginous end-plate of the baboon lumbar spine.

The viscoelastic behavior of the cartilaginous end-plate of the baboon (Papio anubis) was studied in an experiment on compressive creep. Data were analyzed with the biphasic poroviscoelastic constitutive theory to assess the relative contributions of flow-dependent and flow-independent viscoelastic mechanisms to the observed creep behavior. Material coefficients describing the equilibrium compressive behavior (HA) and both flow-independent (c, tau 1, and tau 2) and flow-dependent (k) viscoelastic effects were determined for the end-plate by the curve-fitting of the theoretical solution to the experimental creep data. Biochemical analyses were performed to test for potential relationships between material properties and composition which may give rise to the viscoelastic behavior of the end-plate. The results indicate that the cartilaginous end-plate has a hydraulic permeability of 14.3 x 10(-14) m4/N-s, which is associated with rapid transport and pressurization of the interstitial fluid in response to loading and an increased emphasis on flow-independent viscoelastic effects. Biochemical analyses for water, sulfated glycosaminoglycan content, and hydroxyproline indicate that the end-plate of the baboon is compositionally similar to the cartilaginous end-plate in humans. Interpretation of the mechanical and compositional data suggests that fluid pressurization in the cartilaginous end-plate may be important in the maintenance of a uniform stress distribution across the boundary between vertebral body and intervertebral disc.

Animals↗
PubMed1982

Evaluation of tension and compression forces in the canine femur in vivo.

In order to verify the existence of tension and compression forces from the cortical surface of canine femora, rosette strain gauges and a radio telemetry system were used to observe the animals during normal locomotion. Surface strain measured from the lateral cortical surface was consistently in tension whereas surface strain measured from the medial cortical surface was in compression. This data supported in vitro work which showed that eccentric loading of bone results in the convex side of bone being in tension and the concave side of bone being in compression.

Animals↗
PubMed2002

Internet2-based 3D PET image reconstruction using a PC cluster.

We describe an approach to fast iterative reconstruction from fully three-dimensional (3D) PET data using a network of PentiumIII PCs configured as a Beowulf cluster. To facilitate the use of this system, we have developed a browser-based interface using Java. The system compresses PET data on the user's machine, sends these data over a network, and instructs the PC cluster to reconstruct the image. The cluster implements a parallelized version of our preconditioned conjugate gradient method for fully 3D MAP image reconstruction. We report on the speed-up factors using the Beowulf approach and the impacts of communication latencies in the local cluster network and the network connection between the user's machine and our PC cluster.

Algorithms↗
PubMed2025

CREMSA: compressed indexing of (ultra) large multiple sequence alignments.

MOTIVATION: Recent viral outbreaks motivate the systematic collection of pathogenic genomes in order to accelerate their study and monitor the apparition/spread of variants. Due to their limited length and temporal proximity of their sequencing, viral genomes are usually organized, and analyzed as oversized Multiple Sequence Alignments (MSAs). Such MSAs are largely ungapped, and mostly homogeneous on a column-wise level but not at a sequential level due to local variations, hindering the performances of sequential compression algorithms. RESULTS: In order to enable an efficient handling of MSAs, including subsequent statistical analyses, we introduce CREMSA (Column-wise Run-length Encoding for MSAs), a new index that builds on sparse bitvector representations to compress an existing or streamed MSA, all the while allowing for an expressive set of accelerated requests to query the alignment without prior decompression. Using CREMSA, a 65 GB MSA consisting of 1.9M SARS-CoV 2 genomes could be compressed into 22 MB using less than half a gigabyte of main memory, while executing access requests in the order of 100 ns. Such a speed up enables a comprehensive analysis of covariation over this very large MSA. We further assess the impact of the sequence ordering on the compressibility of MSAs and propose a resorting strategy that, despite the proven NP-hardness of an optimal sort, induces greatly increased compression ratios at a marginal computational cost. AVAILABILITY AND IMPLEMENTATION: CREMSA is freely accessible at https://gitlab.univ-lille.fr/cremsa/cremsa. The Snakemake workflow for the benchmarks is available at: https://gitlab.univ-lille.fr/cremsa/bench. The data used in the paper is on Zenodo at https://zenodo.org/records/14698859 and https://zenodo.org/records/15100011.

SARS-CoV-2↗
PubMed2002

Public health, GIS, and the internet.

Internet access and use of georeferenced public health information for GIS application will be an important and exciting development for the nation's Department of Health and Human Services and other health agencies in this new millennium. Technological progress toward public health geospatial data integration, analysis, and visualization of space-time events using the Web portends eventual robust use of GIS by public health and other sectors of the economy. Increasing Web resources from distributed spatial data portals and global geospatial libraries, and a growing suite of Web integration tools, will provide new opportunities to advance disease surveillance, control, and prevention, and insure public access and community empowerment in public health decision making. Emerging supercomputing, data mining, compression, and transmission technologies will play increasingly critical roles in national emergency, catastrophic planning and response, and risk management. Web-enabled public health GIS will be guided by Federal Geographic Data Committee spatial metadata, OpenGIS Web interoperability, and GML/XML geospatial Web content standards. Public health will become a responsive and integral part of the National Spatial Data Infrastructure.

Geographic Information Systems↗
PubMed1986

Sonographic evaluation of cerebral cortical mantle thickness in the fetus and neonate with hydrocephalus.

Sonographic measurement of the occipital, parietal, and frontal cerebral cortical mantle in ten neonates and ten fetuses with moderate to marked hydrocephalus was performed. In 11 of 14 (78.5 per cent) of the neonatal scans and in 10 of 12 (83 per cent) of the fetal scans, the occipital cortical mantle was less than that of the frontal cortical mantle. This difference varied from 1 to 16 mm. While prognostic data regarding compression of the cerebral mantle from ventricular dilatation exist, they are based upon measurements of the frontal-parietal and not the occipital mantle. Because of the difference observed, if these data are to be used in management, the comparable cerebral cortical mantle should be measured.

Cerebral Cortex↗
PubMed1999

Viability of deformed cells.

Most of the researchers in the field of cryobiology believe that the mechanism of damage during freezing with low cooling rates is chemical and related to the hypertonicity of the extracellular solution. However, there is some evidence to indicate that cells may be destroyed during freezing also by compression between ice crystals. We have developed an experimental procedure to study the effect of cell compression on viability. Using human prostate primary adenoma cancer cells we show that cell viability decreases steeply when cells are compressed to 30% of their original diameter. If uniform expansion of cell membrane is assumed, this corresponds to a 50% increase in the cell membrane surface area. A simple mathematical model shows that the temperature at which the compression effect may cause cell damage is related to the spacing between ice crystals. When the ice crystals are spaced at distances comparable to the cell diameter the model combined with our experimental data predicts compression damage at about -1.8 degrees C. This is consistent with experimental observation on frozen cell destruction in the presence of antifreeze proteins.

Adenocarcinoma↗