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PubMed2000

CPR artifact removal from human ECG using optimal multichannel filtering.

The purpose of this study was to assess whether the artifacts presented by precordial compressions during cardiopulmonary resuscitation could be removed from the human electrocardiogram (ECG) using a filtering approach. This would allow analysis and defibrillator charging during ongoing precordial compressions yielding a very important clinical improvement to the treatment of cardiac arrest patients. In this investigation we started with noise-free human ECGs with ventricular fibrillation (VF) and ventricular tachycardia (VT) records. To simulate a realistic resuscitation situation, we added a weighted artifact signal to the human ECG, where the weight factor was chosen to provide the desired signal-to-noise ratio (SNR) level. As artifact signals we used ECGs recorded from animals in asystole during precordial compressions at rates 60, 90, and 120 compressions/min. The compression depth and the thorax impedance was also recorded. In a real-life situation such reference signals are available and, using an adaptive multichannel Wiener filter, we construct an estimate of the artifact signal, which subsequently can be subtracted from the noisy human ECG signal. The success of the proposed method is demonstrated through graphic examples, SNR, and rhythm classification evaluations.

Biomedical Engineering↗

PubMed2005

A 2-D motion detection model for low-cost embedded reconfigurable I/O devices.

A low-cost reconfigurable embedded apparatus for two-dimensional (2-D) motion detection has been developed. This paper briefly outlines the embedded reconfigurable system architecture, and presents in-depth the 2-D motion detection model, which is directly mapped to reconfigurable hardware. Emphasis is placed on the hardware ability to adapt to individual needs of kinetically challenged persons by altering detection thresholds and delays, thus resulting into an efficient low-cost reconfigurable hardware implementation of the model. This paper also presents how the model detects complex motions through a vocabulary of simple motions, and how the system is trained to individual users' needs. Experimental results and integrated applications of the model for text processing are also presented.

Electronics, Medical↗

PubMed1996

Using the field edge correction (FEC) method to generate accurate POCRs and OCRs for asymmetric fields.

Dose planning programs originally intended for use with symmetric fields have been adapted for use with asymmetric fields. An accurate representation of the change in primary beam quality with off-axis distance and depth is essential for accurate dose calculation and is usually represented in the computer as a primary radiation profile or primary off-center ratio (POCR). The original field edge correction (FEC) method described by Cadman [Med. Phys. 22, 457 (1995)] to determine POCRs has been extended to allow accurate POCR values to be obtained to an off-axis distance defined by the corners of the largest field, typically at an off-axis distance of 28.3 cm. This technique requires only routine symmetric field measurements including beam profiles, TMRs, and collimator and phantom scatter factors. The POCRs obtained using the FEC technique were used to generate off-center ratios (OCRs) using the boundary factor technique of Chui et al. [Med. Phys. 15, 92 (1988)]. Excellent agreement with measured values was obtained for cross-beam OCRs using a 10 x 10-cm2 field defined by a single set of asymmetric jaws with a field center offset of 15 cm and for diagonal OCRs using a 20 x 20-cm2 field with each pair of jaws in a half-blocked configuration.

Biophysical Phenomena↗

PubMed2005

Editing at the crossroad of innate and adaptive immunity.

Genetic information can be altered through the enzymatic modification of nucleotide sequences. This process, known as editing, was originally identified in the mitochondrial RNA of trypanosomes and later found to condition events as diverse as neurotransmission and lipid metabolism in mammals. Recent evidence reveals that editing enzymes may fulfill one of their most essential roles in the defense against infectious agents: first, as the mediators of antibody diversification, a step crucial for building adaptive immunity, and second, as potent intracellular poisons for the replication of viruses. Exciting questions are raised, which take us to the depth of the intimate relations between vertebrates and the microbial underworld.

Animals↗

PubMed1986

Percutaneous gastrostomy and gastroenterostomy: 1. Techniques derived from laboratory evaluation.

Various techniques, guidance systems, instruments, and the postmortem effects of percutaneous gastrostomy (PG) and percutaneous gastroenterostomy (PGE) were evaluated in 30 laboratory animals and five human cadavers. Methods to distend the stomach included air, fluid, intragastric balloon, and percutaneous needle inflation; a variety of trocar systems and catheters inserted by Seldinger technique (including those adapted from other uses and several designed specifically) were assessed. Fluoroscopy was the preferred guidance system, though sonography proved valuable (liver position, depth calculation to the stomach, localization of vessels to avoid), and the entire PG procedure was performed under sonographic guidance in four animals. Although the procedure was safe in most cases, several major complications did occur: laceration of a low-lying liver with exsanguination, malpositioned catheters in the lesser sac and adjacent to the spleen, and violation of the backwall of the stomach with laceration of celiac and splenic vessels. The animals and cadavers underwent autopsy. Autopsy revealed that firm gastrocutaneous tracts were formed by 7 days. There were few instances of wound infection, intraperitoneal fluid leakage, or evidence of trauma to the stomach when the catheters were well seated. Injury to the inferior epigastric artery is a potential hazard, and in cadaver dissections was located between the middle third and outer margin of the rectus abdominis muscle. Laboratory experience has been, and continues to be, an important means to improve and use new techniques for PG and PGE.

Animals↗

PubMed1976

Biomedical results of the Skylab Program.

Skylab, the fourth in a logical sequence of USA manned space flight projects following Mercury, Gemini and Apollo, presented life scientists with their first opportunity for an in-depth study of man's response to the space environment. Extensive medical investigations were undertaken to increase our understanding of man's adaptation to the space environment and his readaptation to gravity upon return to earth. The flight durations of the three Skylab missions were progressively increased from 28 days to 59 days and, finally, 84 days. The results of these investigations of the various body systems clearly demonstrated that man can adapt to zero gravity and perform useful work during long-duration space flight. However, definite changes (some unexpected) in the vestibular, cardiovascular, musculo-skeletal, renal and electrolyte areas were documented. The most significant were: the occurrence of space motion sickness early in the missions; diminished orthostatic tolerance, both in-flight and post-flight; moderate losses of calcium, phosphorus and nitrogen; and decreased tolerance for exercise post-flight. The mechanisms responsible for these physiological responses must be understood and, if necessary, effective countermeasures developed before man can endure unlimited exposure to space flight.

Adaptation, Physiological↗

PubMed1979

Estimation of size of infarcted focus by spatial quantitative vectorcardiography in patients with acute anterior myocardial infarction.

The study included 113 patients with acute myocardial infarction of the left ventricular anterior wall. The patients were repeatedly followed up from the first hours of the affection onward in the course of the individual stages of treatment (stage of intensive monitoring and therapy; intermediate stage; initial rehabilitation with application of active therapy; early mobilization, activation and rehabilitation). A new approach to the estimation of the size of the infarcted focus is described, namely, the method using spatial quantitative vectorcardiography. It was found that the spatial localization of the 40-ms vector, especially its azimuth, is a specific indicator, with the aid of which the localization, extent and depth of the lesion in the left ventricular anterior wall can be assessed with a high probability in most instances. The compensatory adaptive and reparative capacity of the affected myocardium, estimated on the basis of spatial quantitative VCG, is closely correlated with the size of the infarcted focus.

Humans↗

PubMed1978

Radio telemetry system for obtaining body temperature during simulated diving to 1000 FSW.

An implantable radio telemetry system for transmitting deep body temperatures from dogs subjected to hyperbaric conditions was designed and tested. The design was adapted from a transmitter described by J. L. Riley, and was successfully tested both in vitro and in vivo to a simulated depth of 1000 FSW. Circuit schematic, printed circuit layout, and component layout are given.

Animals↗

PubMed1993

Anatomy of the human temporomandibular joint. An updated comprehensive review.

This article is an in-depth review of the current knowledge on human temporomandibular joints (TMJ's). All aspects of joint anatomy are described with emphasis on adaptability to biochemical stimuli throughout life. Each TMJ is a pressure-bearing compound double synovial joint. TMJ's are unique in having a movement not only controlled by the morphology of the joint per se but also by the dentition at the other end of the lever system. During life the temporal, condylar and discal articular surfaces undergo remodelling. The synovium is an important joint component which contributes to nourish and lubricate the avascular surfaces and has bactericidal properties. The joint capsule has privileged relationships anteriorly with the lateral pterygoid muscle. This muscle has two heads that show functionally reciprocal activation. The exact insertion and role of the superior head of the lateral pterygoid muscle remains controversial. The disc has a very low coefficient of friction and compensates for the lack of congruence between articular surfaces. Biomechanically it is stabilized between condyle and articular eminence by its thick rim which has special viscoelastic properties. Apart from the viscoelastic deformations the other important mechanism of disc stabilization seems to be related with the structure of some of the disc attachments.

Humans↗

PubMed2001

Factors affecting maternal role attainment among low-income, Thai, HIV-positive mothers.

This phenomenological study used content analysis of interview data to explore factors affecting maternal role attainment in a convenience sample of 39 low-income, Thai, HIV-positive mothers selected for their successful adaptation. All mothers reported feeling comfortable in their maternal roles and achieved greater than 80% of the total score on the Maternal Behavioral Questionnaire. In-depth interviews were conducted regarding the life experience of the mothers. The results revealed the mothers' uses of internal and external resources to attain their maternal roles. Six factors were identified: (a) setting a purpose for life, that is, to raise the infant; (b) keeping secrets from others; (c) a feeling of normalization; (d) having good quality of support from others; (e) having hope for an HIV cure; and (f) receiving accessible, pleasant health services that protect anonymity regarding HIV status. The results suggest that nurses can promote maternal role attainment by supporting the mothers' management style.

Adaptation, Psychological↗

PubMed2026

No receptor-binding domain adaptation detected in within-host H5N1 surveillance of 4,559 US dairy outbreak sequences.

BACKGROUND: The 2024-2026 US H5N1 clade 2.3.4.4b dairy cattle outbreak has been characterised primarily through consensus-level phylogenetics. Whether mammalian-adaptation variants are emerging at sub-consensus frequencies within infected hosts, particularly at the haemagglutinin receptor-binding domain (RBD), remains unknown because no systematic within-host variant analysis of the public sequencing corpus has been performed. METHODS: We conducted a pre-registered, corpus-wide intrahost single-nucleotide variant (iSNV) analysis of all publicly available H5N1 cattle, feline-spillover, and retail-milk sequences on the NCBI Sequence Read Archive (4559 samples across 7 BioProjects). A dual-caller concordance pipeline (iVar + LoFreq) with empirically determined allele frequency (AF) threshold (3%, set via four-criterion validation including synthetic spike-in controls) was applied to an 11-site Tier 1 mammalian-adaptation panel spanning the polymerase complex, haemagglutinin RBD, and accessory proteins. Within-host nucleotide diversity was compared across host categories. RESULTS: The HA RBD sites Q226L and G228S (H3 numbering) showed zero detections across >4300 adequately sequenced samples at all AF thresholds tested (1-5%), despite the pipeline detecting other non-synonymous variants at these exact codon positions (upper 95% CI for prevalence: 0.08%). Seven of eleven adaptation sites carried statistically significant iSNV signals after Bonferroni correction (corrected α = 0.00417), though all at low prevalence (≤2.95%). Genotype stratification showed that most polymerase-site detections reflected genotype structure rather than within-host emergence: the apparent PB2 631 L→M "reversion" was largely the ancestral avian state of the D1.1 genotype (20 of 23 detections), which never acquired the 631L mammalian adaptation, with only two genuine sub-consensus events in the B3.13 background, while consensus-level PB2 701N was a fixed feature of the D1.1 genotype (10 of 14 detections) rather than independent sub-consensus emergence. Cattle exhibited significantly higher within-host nucleotide diversity than feline-spillover samples (π = 1.59 × 10-4 vs 6.11 × 10-5; Kruskal-Wallis p = 6.6 × 10-15), a finding that persisted after depth-matching (p = 4.6 × 10-5); this may reflect prolonged mammary-gland infection, though sampling differences and host biology cannot be excluded. CONCLUSIONS: We did not detect HA receptor-switching adaptation (the acquisition of human-type α2,6 receptor binding via Q226L/G228S) at any tested allele frequency in the US dairy H5N1 outbreak. Sub-consensus mammalian-adaptation signals exist at polymerase-complex sites but at low prevalence, are genotype-structured rather than independently recurrent, and require functional characterisation before informing risk assessment.

Dairy cattle↗

PubMed2025

Landscape genomics analysis reveals the genetic basis underlying cashmere goats and dairy goats adaptation to frigid environments.

Understanding the genetic mechanism of cold adaptation in cashmere goats and dairy goats is very important to improve their production performance. The purpose of this study was to comprehensively analyze the genetic basis of goat adaptation to cold environments, clarify the impact of environmental factors on genome diversity, and lay the foundation for breeding goat breeds to adapt to climate change. A total of 240 dairy goats were subjected to genome resequencing, and the whole genome sequencing data of 57 individuals from 6 published breeds were incorporated. By integrating multiple approaches such as phylogenetic analysis, population structure analysis, gene flow and population history exploration, selection signal analysis, and genome-environment association analysis, an in-depth investigation was carried out. Phylogenetic analysis unraveled the genetic relationships and differentiation patterns among dairy goats and other goat breeds. Through signal analysis (θπ, FST, XP-CLR), we identified numerous candidate genes associated with cold adaptation in dairy goats (STRIP1, ALX3, HTR4, NTRK2, MRPL11, PELI3, DPP3, BBS1) and cashmere goats (MED12L, MARC2, MARC1, DSG3, C6H4orf22, CHD7, MYPN, KIAA0825, MITF). Genome-environment association (GEA) analysis confirmed the link between these genes and environmental factors. Moreover, a detailed analysis of the critical genes C6H4orf22 and STRIP1 demonstrated their significant roles in the geographical variations of cold adaptation and allele frequency differences among different breeds. This study contributes to understanding the genetic basis of cold adaptation, providing crucial theoretical support for precision breeding programs aimed at improving production performance in cold regions by leveraging adaptive alleles, thereby ensuring sustainable animal husbandry.

Environmental adaptation↗

PubMed2005

The watercolor illusion and neon color spreading: a unified analysis of new cases and neural mechanisms.

Coloration and figural properties of neon color spreading and the watercolor illusion are studied using phenomenal and psychophysical observations. Coloration properties of both effects can be reduced to a common limiting condition, a nearby color transition called the two-dot limiting case, which clarifies their perceptual similarities and dissimilarities. The results are explained by the FACADE neural model of biological vision. The model proposes how local properties of color transitions activate spatial competition among nearby perceptual boundaries, with boundaries of lower-contrast edges weakened by competition more than boundaries of higher-contrast edges. This asymmetry induces spreading of more color across these boundaries than conversely. The model also predicts how depth and figure-ground effects are generated in these illusions.

Adaptation, Ocular↗

PubMed2004

Experience of gastric cancer survivors and their spouses in Korea: secondary analysis.

PURPOSE: The purpose of this study was to explore the experiences of gastric cancer couples in Korea and to generate a substantive theory integrating the experiences of gastric cancer survivors and their spouses as a whole. The specific aims of this study were to explore major problems gastric cancer couples faced and how they resolved these problems, focusing on inter-relational dynamics within the couples and on similarities and differences between the couples. METHODS: This was a secondary analysis study using grounded theory techniques. The study used the data of 11 married couples which was collected from in-depth interviews from two primary studies. The unit of analysis was dyads of gastric cancer survivors and their spouses. RESULT: The basic social psychological process that emerged from the analysis was "taking charge of their health." Major categories involved in this process were identified as 1) adjusting to new diets, 2) reinforcing physical strength, 3) seeking information, 4) strengthening Ki, 5) lowering life-expectations, and 6) going their separate ways. These six categories represent major strategies in overcoming critical problems that occurred in day-to-day experiences. In terms of the process, the first five categories characterize the earlier stage of the process of "taking charge of their health," while "going their separate ways" indicates the later stage and also the beginning of their separate ways: "pursuing spiritual life" for the survivors, and "preparing for the future" for the spouses. CONCLUSIONS: The results of this study will help design family care for the people with gastric cancer by providing in-depth understanding and insight on the lives of gastric cancer couples.

Adaptation, Psychological↗

PubMed2004

Biomechanical properties of human articular cartilage under compressive loads.

The function of articular cartilage is to support and distribute loads and to provide lubrication in the diarthrodial joints. Cartilage function is described by proper mechanical and rheological properties, strain and depth-dependent, which are not completely assessed. Unconfined and confined compression are commonly used to evaluate the Young's modulus (E) and the aggregate modulus (H(A)), respectively. The Poisson's ratio (nu) can be calculated indirectly from the equilibrium compression data, or using the biphasic indentation technique; it has recently been optically evaluated by using video microscopy during unconfined compression. The transient response of articular cartilage during confined compression depends on its permeability k; a constant value of k can be easily identified by a simple analytical model of confined compression tests, whereas more complex models or direct measurements (permeation tests) are needed to study the permeability dependence on deformation. A poroelastic finite element model of articular cartilage was developed for this purpose. The elastic parameters (E,nu) of the model were evaluated performing unconfined compression creep tests on human articular cartilage disks, whereas k was identified from the confined test response. Our combined experimental and computational method can be used to identify the parameters that define the permeability dependence on deformation, as a function of depth from articular surface.

Adaptation, Physiological↗

PubMed2002

Reproducible volar partial lacerations in flexor tendons: a new device for biomechanical studies.

A device was designed to create clinically relevant, precise partial flexor digitorum profundus tendon lacerations for in vitro studies but can be adapted for in vivo studies. This caliper-based system utilizes a direct measurement of the tendon height and assumes an elliptical cross section to select the depth of the cut. The accuracy was tested on 60 cuts on 12 human tendons lacerated to an expected 50% or 75% of their cross-sectional area, based on the assumption that the cross-section was elliptical in shape. The cuts were made in portions of the tendon that varied in cross-sectional shape and size. The cut surface of the laceration was colored with Methylene blue and then the laceration was completed. The tendon cross-section was digitally imaged and the respective areas of the stained and unstained regions were evaluated using image-processing software. The mean lacerated areas were 52% (SD 5%) and 73% (SD 6%) for targeted lacerations of 50% and 75%, respectively. The device thus appears to be accurate within an acceptable 5% margin of error from the expected area, and adaptable to intra- and inter-tendinous size variations.

Biomechanical Phenomena↗

PubMed2002

Understanding the contribution of binocular vision to the control of adaptive locomotion.

Abstract. Although the contribution of binocular vision to reach-to-grasp movements has been extensively studied, it has been largely ignored in locomotion. The aim of these studies was to explore the role of binocular vision during the approach phase and step over the obstacle and the contribution of head movements to acquisition of depth information under monocular vision. Binocular and monocular vision was manipulated in different phases using either an eye patch or liquid crystal glasses. Head movement relative to the trunk was restricted in the first experiment by a modified Ferno Universal Head Immobilizer attached to a rigid board strapped to the participant's back. Whole body kinematics were collected by placing infrared diodes on anatomical landmarks and using an Optotrak imaging system. Several measures related to head and limb movement were analyzed. Three major findings emerged from these studies. First, binocular vision is important for the acquisition of accurate information about the surrounding environment: accuracy but not precision of limb elevation over the obstacle was adversely affected when binocular vision was unavailable. Second, motion parallax due to self-motion provides the most critical depth information and it can be used to partially compensate for the loss of binocular vision. Although head movement is not essential to augment depth information, it is important for reorientation of the visual field to obtain the necessary information about the moving limbs when visual field is suddenly limited under monocular vision. Third, step over the obstacle is pre-planned based on visual information acquired during the approach phase: changes in visual condition during the adaptive step do not influence the limb trajectory. Collectively these three studies provide unique insights into the contribution of binocular vision during adaptive locomotion.

Adaptation, Psychological↗

PubMed2004

Biomechanical aspects of marginal bone resorption around osseointegrated implants: considerations based on a three-dimensional finite element analysis.

OBJECTIVES: Although bone loss around implants is reported as a complication when it progresses uncontrolled, resorption does not always lead to implant loss, but may be the result of biomechanical adaptation to stress. To verify this hypothesis, a three-dimensional finite element analysis was performed and the influence of marginal bone resorption amount and shape on stress in the bone and implant was investigated. MATERIAL AND METHODS: A total of nine bone models with an implant were created: a non-resorption (Base) model and eight variations, in which three different resorption depths were combined with pure vertical or conical (vertical-horizontal) resorption. Axial and buccolingual forces were applied independently to the occlusal node at the center of the superstructure. RESULTS: Regardless of load direction, bone stresses were higher in the pure vertical resorption (A) models than in the Base model, and increased with resorption depth. However, cortical bone stress was much lower in the conical resorption models than in both the Base and A models of the same resorption depth. An opposite tendency was observed in the cancellous bone under buccolingual load. Under buccolingual load, highest stress in the implant increased linearly with the resorption depth for all the models and its location approached the void existing below the abutment screw. CONCLUSIONS: The results of this analysis suggest that a certain amount of conical resorption may be the result of biomechanical adaptation of bone to stress. However, as bone resorption progresses, the increasing stresses in the cancellous bone and implant under lateral load may result in implant failure.

Adaptation, Physiological↗