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PubMed1992

Near-infrared imaging in vivo (I): Image restoration technique applicable to the NIR projection images.

To enhance spatial resolution of NIR projection images in vivo, we performed refocusing of NIR projection images of human forearm of about 50 mm thickness. A volunteer's forearm was illuminated by parallel light beam-flux, and then projection images at 750 nm was measured with a Pertier-cooled CCD video camera and digitized. For refocusing computation, PSF of the light transmitted through the tissue was calculated by general equation proposed by van der Zee and Delpy (1988). Simple inverse, constrained least squares, and Wiener filters were tested as refocusing algorithms. Wiener filter gave the best result in terms of image quality and computation time. By applying Wiener filter to the image refocusing of NIR projection images of human forearm, we obtained enhanced spatial resolution.

Evaluation Studies as Topic↗
PubMed2026

The application of artificial intelligence in healthcare practice: A mapping review of systematic reviews.

Artificial intelligence (AI) is rapidly transforming healthcare practice, with growing evidence supporting its use in diagnosis, prognosis, treatment planning, and operational decision-making. The proliferation of systematic reviews in recent years underscores the need for an updated synthesis of the literature to inform research, policy, and practice. We searched PubMed, Web of Science, Scopus, IEEE Xplore, and CINAHL for systematic reviews and meta-analyses published between 2019 and February 2026. Eligible reviews focused on AI applications in healthcare practice, were peer-reviewed, and written in English. A total of 368 reviews met the inclusion criteria. Publication volume increased steadily, peaking in 2025. AI research was concentrated in high-density domains, such as radiology, oncology, and critical care. Across reviews, diagnostic imaging, electronic health record (EHR) data, and biomarkers/laboratory results accounted for 68% of training data sources, though newer data types, such as wearable device and sensor data, emerged from 2022 onward. Diagnosis, prognosis, and treatment comprised over 80% of AI applications, with novel uses emerging in recent years, such as AI-assisted clinical documentation (e.g., ambient documentation tools) and patient education. Ethical concerns were reported in 78.5% of reviews, with privacy, model accuracy, data and algorithmic bias, and explainability as recurrent themes. The proportion of reviews reporting ethical concerns increased from 2021 to 2025. AI applications in healthcare are expanding in scope, diversifying in data sources, and evolving toward novel clinical and operational uses. The human-centered AI or augmented intelligence paradigm, integrating computational precision with clinical expertise, holds significant promise but will require parallel advances in governance, regulatory frameworks, and ethical oversight to ensure safe adoption.

Artificial Intelligence↗
PubMed1992

Evidence of hyperplanes in the genetic learning of neural networks.

Genetic Algorithms have been successfully applied to the learning process of neural networks simulating artificial life. In previous research we compared mutation and crossover as genetic operators on neural networks directly encoded as real vectors (Manczer and Parisi 1990). With reference to crossover we were actually testing the building blocks hypothesis, as the effectiveness of recombination relies on the validity of such hypothesis. Even with the real genotype used, it was found that the average fitness of the population of neural networks is optimized much more quickly by crossover than it is by mutation. This indicated that the intrinsic parallelism of crossover is not reduced by the high cardinality, as seems reasonable and has indeed been suggested in GA theory (Antonisse 1989). In this paper we first summarize such findings and then propose an interpretation in terms of the spatial correlation of the fitness function with respect to the metric defined by the average steps of the genetic operators. Some numerical evidence of such interpretation is given, showing that the fitness surface appears smoother to crossover than it does to mutation. This confirms indirectly that crossover moves along privileged directions, and at the same time provides a geometric rationale for hyperplanes.

Algorithms↗
PubMed1986

Interactive display of three-dimensional radionuclide distributions.

Tomographic images of three-dimensional radionuclide distributions are usually presented as a set of parallel planar slices. A technique has been developed to enable the observer to perceive directly the three-dimensional morphology of the activity distribution by displaying iso-count surfaces. Computer graphics techniques have been used to present shaded surface images using a conventional nuclear medicine computer system. Because of the relatively coarse spatial sampling of radionuclide tomograms, a smooth shading algorithm based on a local polynomial fit procedure was developed. By using a simple solid model approach for data storage the program executes interactively, allowing the observer to view the reconstructed activity distribution from any aspect. The technique has been successfully applied to radionuclide tomograms of several organs, and promises to be particularly useful for the display or cardiac blood pool data.

Algorithms↗
PubMed1986

Modelling of the control of heart rate by breathing using a kernel method.

The process of the breathing (input) to the heart rate (output) of man is considered for system identification by the input-output relationship, using a mathematical model expressed as integral equations. The integral equation is considered and fixed so that the identification method reduces to the determination of the values within the integral, called kernels, resulting in an integral equation whose input-output behaviour is nearly identical to that of the system. This paper uses an algorithm of kernel identification of the Volterra series which greatly reduces the computational burden and eliminates the restriction of using white Gaussian input as a test signal. A second-order model is the most appropriate for a good estimate of the system dynamics. The model contains the linear part (first-order kernel) and quadratic part (second-order kernel) in parallel, and so allows for the possibility of separation between the linear and non-linear elements of the process. The response of the linear term exhibits the oscillatory input and underdamped nature of the system. The application of breathing as input to the system produces an oscillatory term which may be attributed to the nature of sinus node of the heart being sensitive to the modulating signal the breathing wave. The negative-on diagonal seems to cause the dynamic asymmetry of the total response of the system which opposes the oscillatory nature of the first kernel related to the restraining force present in the respiratory heart rate system. The presence of the positive-off diagonal of the second-order kernel of respiratory control of heart rate is an indication of an escape-like phenomenon in the system.

Heart Rate↗
PubMed1988

Three-dimensional structure of acyl carrier protein determined by NMR pseudoenergy and distance geometry calculations.

Distance constraints from two-dimensional NMR cross-relaxation data are used to derive a three-dimensional structure for acyl carrier protein from Escherichia coli. Several approaches to structure determination are explored. The most successful proves to be an approach that combines the early stages of a distance geometry program with energy minimization in the presence of NMR constraints represented as pseudopotentials. Approximately 450 proton to proton distance constraints including 50 long-range constraints were included in these programs. Starting structures were generated at random by the distance geometry program and energies minimized by a molecular mechanics module to give final structures. Seven of the structures were deemed acceptable on the basis of agreement with experimentally determined distances. Root-mean-square deviations from the mean of these structures for backbone atoms range from 2 to 3 A. All structures show three roughly parallel helices with hydrophobic residues facing inward and hydrophilic residues facing outward. A hydrophobic cleft is recognizable and is identified as a likely site for acyl chain binding.

Acyl Carrier Protein↗
PubMedDate not supplied

The myocardial microangiopathy in human and experimental diabetes mellitus. (A microscopic, ultrastructural, morphometric and computer-assisted symbolic-logic analysis).

The following microscopical aspects were found in the small intramural arteries in the myocardium of 30 diabetic patients: endothelial proliferations with focal protuberances leading to partial narrowing of the lumen, increased thickness of the arterial wall due to fibrosis and accumulations of neutral mucopolysaccharides: alteration of elastic fibres. Morphometrically, the arterial wall thickness and the arterial diameter were increased whereas the arterial density decreased in the diabetic heart. In 25 rats with streptozotocin-induced diabetes the small intramyocardial arteries were investigated at 11 to 40 weeks of diabetic state. Using morphometrical analysis a constant increase of arterial wall thickness paralleling the diabetes duration was found. Microscopically, the lesions consist in endothelial proliferation with bridging across the vascular lumen and slight perivascular and diffuse fibrosis. Ultrastructurally, the capillary basal lamina was thickened in the diabetic myocardium. In order to investigate the morphometrical data we used symbolic-logic as a decision method, by applying an original computer program based on the Quine-McCluskey algorithm. All our results together with the final symbolic-logic expression suggest that damage of the small intramyocardial arteries plays an important role in the pathogenesis of diabetic cardiomyopathy.

Aged↗
PubMed1991

A platform for biological sequence comparison on parallel computers.

We have written two programs for searching biological sequence databases that run on Intel hypercube computers. PSCANLIB compares a single sequence against a sequence library, and PCOMPLIB compares all the entries in one sequence library against a second library. The programs provide a general framework for similarity searching; they include functions for reading in query sequences, search parameters and library entries, and reporting the results of a search. We have isolated the code for the specific function that calculates the similarity score between the query and library sequence; alternative searching algorithms can be implemented by editing two files. We have implemented the rapid FASTA sequence comparison algorithm and the more rigorous Smith-Waterman algorithm within this framework. The PSCANLIB program on a 16 node iPSC/2 80386-based hypercube can compare a 229 amino acid protein sequence with a 3.4 million residue sequence library in approximately 16 s with the FASTA algorithm. Using the Smith-Waterman algorithm, the same search takes 35 min. The PCOMPLIB program can compare a 0.8 million amino acid protein sequence library with itself in 5.3 min with FASTA on a third-generation 32 node Intel iPSC/860 hypercube.

Algorithms↗
PubMed1988

Computer-aided sleep staging in clinical environment.

In the present paper we will comment on how we have been implementing computer-aided sleep staging (CAS) in the Department of Psychiatry, Erasmus Hospital (Free University of Brussels). Major features of our CAS include real-time stage estimation, full report and hypnogram available in the morning, and evolution of state variables throughout the night (e.g. electroencephalographic spectral characteristics, eye movement density, myographic activity). Parallel, we report an extensive validation study of this system on 50 subjects divided in two groups of 25 patients with psychiatric diseases, and 25 normal subjects.

Adult↗
PubMed1991

The immune system as a neural network: a multi-epitope approach.

The term "neural network" has been applied to arrays of simple activation units linked by weighted connections. If the connections are modified according to a defined learning algorithm, such networks can be trained to store and retrieve patterned information. Memories are distributed throughout the network, allowing the network to recall complete patterns from incomplete input (pattern completion). The major biological application of neural network theory to date has been in the neurosciences, but the immune system may represent an alternative organ system in which to search for neural network architecture. Previous applications of parallel distributed processing to idiotype network theory have focused upon the recognition of individual epitopes. We argue here that this approach may be too restrictive, underestimating the power of neural network architecture. We propose that the network stores and retrieves large, complex patterns consisting of multiple epitopes separated in time and space. Such a network would be capable of perceiving an entire bacterium, and of storing the time course of a viral infection. While recognition of solitary epitopes occurs at the cellular level in this model, recognition of structures larger than the width of an antibody binding site takes place at the organ level, via network architecture integration of, i.e. individual epitope responses. The Oudin-Cazenave enigma, the sharing of idiotypic determinants by antibodies directed against distinct regions of the same antigen, suggests that some network level of integration of the individual clonal responses to large antigens does occur. The role of cytokines in prior neural network models of the immune system is unclear. We speculate that cytokines may influence the temperature of the network, such that changes in the cytokine milieu serve to "anneal" the network, allowing it to achieve the optimum steady-state in the shortest period of time.

Artificial Intelligence↗
PubMed1990

Pharmacokinetic-pharmacogenetic modelling in the detection of polymorphisms in xenobiotic metabolism.

Study of the genetic control of xenobiotic metabolism is hindered in the areas of detecting new polymorphisms and estimating the frequency and enzyme activity of each phenotype. Using computer simulation we have looked at pharmacogenetic-pharmacokinetic models based on two alleles under Hardy-Weinberg equilibrium. The distributions of the area under the concentration-time curve (AUC) or urinary ratios were modelled and the effects of incomplete urine collections, sequential, parallel and non-linear pathways investigated. The statistical methods for the detection of bimodality in these distributions were explored. The drug/metabolite ratio, which has a good theoretical basis, was confirmed to be most sensitive and robust to changes in bioavailability, urinary excretion, hepatic blood flow and variation in non-polymorphic enzyme activity but not parallel, sequential or non-linear routes of metabolism. Graphical methods, while able to illustrate deviations from normality, were not specific in detecting bimodality and the hypothesis testing methods were found to be heavily dependent upon their assumptions.

Algorithms↗
PubMedDate not supplied

The determination of the three-dimensional structure of barley serine proteinase inhibitor 2 by nuclear magnetic resonance, distance geometry and restrained molecular dynamics.

The solution structure of the 64 residue structured domain (residues 20-83) of barley serine proteinase inhibitor 2 (BSPI-2) is determined on the basis of 403 interproton distance, 34 phi backbone torsion angle and 26 hydrogen bonding restraints derived from n.m.r. measurements. A total of 11 converged structures were computed using a metric matrix distance geometry algorithm and refined by restrained molecular dynamics. The average rms difference between the final 11 structures and the mean structure obtained by averaging their coordinates is 1.4 +/- 0.2 A for the backbone atoms and 2.1 +/- 0.1 A for all atoms. The overall structure, which is almost identical to that found by X-ray crystallography, is disc shaped and consists of a central four component mixed parallel and antiparallel beta-sheet flanked by a 13 residue alpha-helix on one side and the reactive site loop on the other.

Edible Grain↗
PubMed1990

Principles of management of shotgun wounds.

As an instrument of close range combat, the shotgun has no parallel. At short distances, its destructive capacity parallels that seen from high velocity missile injury. In this study, the history of the shotgun, wound ballistics, principles of initial therapy and special management problems related to shotgun wounds of specific sites are reviewed. An analysis of pooled data on abdominal shotgun wounds is presented. A subset of patients who do not require abdominal exploration exists. Specific problems encountered in defining this subset are enumerated. Three algorithms are presented that summarize our current management approach to shotgun wounds of the torso and extremities.

Abdominal Injuries↗
PubMed1992

Harnessing networked workstations as a powerful parallel computer: a general paradigm illustrated using three programs for genetic linkage analysis.

It is widely accepted that parallel computers, which have the ability to execute different parts of a program simultaneously, will offer dramatic speed-up for many time-consuming biological computations. The paper describes how the use of the machine-independent parallel programming language, Linda, allows parallel programs to run on an institution's network of workstations. In this way, an institution can harness existing hardware, which is often either idle or vastly underutilized, as a powerful 'parallel machine' with supercomputing capability. The paper illustrates this very general paradigm by describing the use of Linda to parallelize three widely used programs for genetic linkage analysis, a mathematical technique used in gene mapping. The paper then discusses a number of technical, administrative and social issues that arise when creating such a computational resource.

Algorithms↗
PubMed1992

Comparing machine-independent versus machine-specific parallelization of a software platform for biological sequence comparison.

A platform program that performs biological sequence comparison provides a case study to compare the relative advantages of a machine-independent approach to parallel computation versus a machine-specific approach. The program consists of two routines: (i) PSCANLIB, which compares a single biological sequence against a database of sequences, and (ii) PCOMPLIB, which compares a database of sequences against another database of sequences, or against itself. The program was first parallelized to run on the Intel Hypercube parallel computer using native Hypercube commands to coordinate the parallel computation. The parallelization logic of the program was then translated into a machine-independent parallel programming language, Linda. These two approaches to parallelization are contrasted in terms of: (i) the expressive power of the logic that coordinates the parallel computation, (ii) the portability of the machine-independent version to other parallel machines and (iii) the relative efficiency of the two versions of the program. In the benchmark tests reported, the benefits of the machine-independent approach were achieved with only a modest sacrifice in efficiency.

Algorithms↗
PubMed1987

Continuous, real-time, noninvasive monitor of blood pressure: Penaz methodology applied to the finger.

The finger blood pressure monitor measures blood pressure continuously and noninvasively by means of a technique described by J. Penaz. The size of the artery is measured when its internal pressure (arterial pressure) equals the external pressure. (At this point, transmural pressure equals zero and the arterial wall is said to be "unloaded.") This unloaded condition is maintained by continuous, automatic adjustments of external pressure on the artery, adjustments that are made simultaneously with and parallel to intraarterial pressure variations. The external pressure then constantly equals internal pressure (arterial blood pressure) and is reported by the monitor as values for systolic, mean, and diastolic pressure. A finger cuff with a built-in light source and detector is used to measure finger artery size, and an inflatable bladder is used to apply the external pressure to the artery. The monitor is microprocessor based; algorithms determine the unloaded artery size approximately every minute and automatically correct for changes possibly induced by smooth muscle contraction or relaxation, and a high-speed electropneumatic servo control system enables automatic calibration and adjustment.

Blood Pressure Determination↗
PubMed1992

[Neoplastic involvement of pulmonary fissures. Diagnostic possibility of high resolution x-ray computed tomography].

Acknowledging fissure invasion by pulmonary tumors located in contact with or in the vicinity of a fissure is an important piece of information for the therapeutic choice, especially in patients whose functional respiratory impairments are a contraindication of pneumonectomy. Fifteen patients with pulmonary neoplasms adjacent to a fissure were studied with standard computed tomography (10 mm sections), completed by high-resolution CT. The findings of the CT studies were compared with those operative reports. On surgery, the oblique fissure was infiltrated in 12 patients, unharmed in 2 others, while the horizontal fissure was infiltrated in 3 patients. Standard CT allowed diagnosing the involvement of the oblique fissure in 4 patients. Thin sections with high-resolution reconstruction algorithms allowed detecting the involvement of the oblique fissure in 13 cases, including one false-positive result. On thin sections, the fissures appear as well-delineated, dense lines. This allows an accurate study of the relationships between the tumor and the fissure, thus increasing the sensitivity of CT for the detection of tumoral extension across the fissures. The orientation of the horizontal fissure, which is almost parallel to the plane of section, makes the study of its relationships with an adjacent mass difficult, even in high-resolution CT.

Humans↗
PubMed1990

Influence of plasma glucose concentration on lumped constant of the deoxyglucose method: effects of hyperglycemia in the rat.

The lumped constant of the deoxyglucose method was determined by the steady-state, model-independent method in the brain of normal conscious rats with arterial plasma glucose concentrations varying from normoglycemia (i.e., 8 mM) to hyperglycemia (i.e., 31 mM). The lumped constant for brain was found to decrease very gradually with increasing arterial plasma glucose concentration from a value of approximately 0.45 in the midnormoglycemic range (i.e., 7-8 mM) to approximately 0.38 at 28-31 mM. 3-O-[14C]Methylglucose was used to assess the distribution of glucose within the brain structures in hyperglycemia; the results indicated that the glucose concentration, and therefore also the values for the lumped constant, remain relatively uniform in hyperglycemia with arterial plasma glucose concentrations as high as 34 mM. The values for the lumped constant for rat brain determined in the present studies were combined with those previously determined in this laboratory for hypoglycemia and normoglycemia by the same method to provide a single source for the values for the lumped constant to be used over the full range of arterial plasma glucose concentrations. In several rats the lumped constant for cephalic extracerebral tissues was also evaluated in parallel with those for the brain. The lumped constant for the cephalic extracerebral tissues was found to be about twice that for brain and to be unaffected by changes in arterial plasma glucose levels.

Algorithms↗