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Results for “Deep generative model”

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PubMed1980

Heating patterns produced by 434 MHz erbotherm UHF 69.

Thermal distributions of 434 MHz Erbotherm H 69 hyperthermia/diathermy generators in tissue-equivalent medium have been investigated. Thermocouples were used to measure temperatures at a set of grid points. Cylindrical and abdominal phantoms were heated and sectioned after heating to measure the temperatures at depth. Results indicate that there is potential for heating deep-seated tumors. The distributions were influenced by the number, shape and geometry of the applicators employed.

Diathermy↗

PubMed1997

The vanishing defibrillator syndrome: incidence, mechanism, and clinical relevance.

Intraperitoneal migration of an abdominally implanted cardioverter defibrillator is a complication not yet fully described. In a consecutive series of 195 patients, migration occurred between 1 and 20 months in 5 (8%) of the 63 patients in whom a subrectus abdomini placement of the generator was chosen. It was unrelated to the patients' clinical characteristics or the defibrillator model. Dysuria and inability to interrogate the device were present in every subject, and the diagnosis was confirmed by the characteristic abdominal x-ray appearance and the findings at the time of surgery. Adhesions involving the omentum, and in one case, the small bowels, were present in three patients and seem to be related to the length of intraabdominal permanence of the generator. Because this complication may be due to specific anatomical characteristics of the aponeurosis of the abdominal muscles, it is likely that its incidence will be unchanged by the use of smaller devices. A close follow-up of the generators implanted deep to the rectus fascia is therefore advisable.

Abdomen↗

PubMed1998

Pain processing traced by magnetoencephalography in the human brain.

The temporal and spatial processing of pain perception in human was traced by magnetoencephalography (MEG). We applied a painful CO2 laser beam to the forearm of 11 normal subjects, and estimated the activated areas using a single equivalent current dipole (ECD) at each time point, and a brain electric source analysis (BESA) as a spatio-temporal multiple source analysis method. The four-source model was found to be the most appropriate; sources 1 and 2 at the secondary sensory cortex (SII) contralateral and ipsilateral to the stimulation, and sources 3 and 4 at the anterior medial temporal area (probably the amygdalar nuclei or hippocampal formation) contralateral and ipsilateral to the stimulation, respectively. Activities in all 4 areas were temporally overlapped. Activity in the primary sensory cortex (SI) contralateral to the stimulated site was not identified. Activity in the cingulate cortex was also not clearly identified. These results are probably due to one or more of the following factors; (1) the cingulate cortex is too deep, (2) the ECDs generated in the cingulate cortex are mainly oriented radially, and (3) the ECDs generated in bilateral hemispheres interfere with each other. No significant or consistent magnetic fields were recorded after 500 msec following the stimulation, probably due to the complicated spatial and temporal overlapping of activities in multiple areas.

Adult↗

PubMedDate not supplied

Fluconazole therapy for experimental cryptococcosis and candidiasis in the rabbit.

Fluconazole is a second-generation azole compound with broad-spectrum antifungal activity. It has been examined in several animal models emphasizing important clinical sites of infection with common yeast pathogens. The drug has an excellent pharmacokinetic profile for central nervous system, renal, and ocular infections; at these sites fluconazole has been successful in the treatment of infections with Cryptococcus neoformans or Candida albicans. On the basis of the experience in animals, fluconazole should be critically evaluated in the treatment of human mycoses such as cryptococcosis of the central nervous system and renal/ocular candidiasis. This agent represents the new wave of interest in the increasingly troublesome problem of deep-seated fungal infections.

Animals↗

PubMed2025

Decoding the Functional Interactome of Non-Model Organisms with PHILHARMONIC.

Despite the widespread availability of genome sequencing pipelines, many genes remain part of the genome's "dark matter," where existing inference tools cannot even begin to guess the biological function of their proteins from sequence alone. This challenge is especially pronounced in organisms that are highly evolutionarily distant from well-studied models, where homology-based methods break down. Here, we describe PHILHARMONIC, a computational method that combines deep learning-based de novo protein interaction network inference with robust unsupervised spectral clustering and remote homology to illuminate functional organization in any non-model organism. From only a sequenced proteome, we show PHILHARMONIC predicts protein functions, functional communities, and higher-order network structure with high accuracy. We validate its performance using experimental gene expression and pathway data in D. melanogaster, and we demonstrate its broad utility by analyzing temperature sensing and stress response pathways in the reef-building coral P. damicornis and its algal symbiont C. goreaui. PHILHARMONIC provides a general-purpose engine for functional discovery and biological hypothesis generation in non-model organisms, enabling systems-level insights across the full diversity of life.

Journal Article↗

PubMed1997

Volumetric transformation of brain anatomy.

This paper presents diffeomorphic transformations of three-dimensional (3-D) anatomical image data of the macaque occipital lobe and whole brain cryosection imagery and of deep brain structures in human brains as imaged via magnetic resonance imagery. These transformations are generated in a hierarchical manner, accommodating both global and local anatomical detail. The initial low-dimensional registration is accomplished by constraining the transformation to be in a low-dimensional basis. The basis is defined by the Green's function of the elasticity operator placed at predefined locations in the anatomy and the eigenfunctions of the elasticity operator. The high-dimensional large deformations are vector fields generated via the mismatch between the template and target-image volumes constrained to be the solution of a Navier-Stokes fluid model. As part of this procedure, the Jacobian of the transformation is tracked, insuring the generation of diffeomorphisms. It is shown that transformations constrained by quadratic regularization methods such as the Laplacian, biharmonic, and linear elasticity models, do not ensure that the transformation maintains topology and, therefore, must only be used for coarse global registration.

Animals↗

PubMed2001

Chimaeras and mosaics for dissecting complex mutant phenotypes.

Back at the first half of the 1980s, there was no mammalian experimental embryology in Hungary. One of us, AN, took up the challenge of establishing a small group in the field. In the absence of local information, AN and his former colleague, Andras Paldi (AP), used their tourist passport to visit several laboratories in Western Europe and collect information and advice. This is how AN and AP ended up one day sitting in Anne McLaren's office in the MRC Mammalian Development Unit at University College, London. They never forgot her endless enthusiasm and the way she clearly explained the important points of preimplantation embryo manipulation, chimaera making and embryo transfer. As well as the extremely useful suggestions, which were crucial to starting the lab in Hungary, they also took back her deep love for embryo development. They remember her telling them, 'never waste an embryo--there is always another unanswered question it can solve'. Many who have been lucky and experienced Anne's spirit and advice later realized how useful it was to generate 'new' ideas by following the 'not wasting' principle. Our views on chimaeras presented below definitely contain elements which grew out from this principle.

Animals↗

PubMedDate not supplied

[An experimental model of the vertical transmission of the Coxsackie-group enteroviruses and its use in developing methods to prevent congenital coxsackievirus infection].

An experimental model of vertical transmission of Coxsackie group enteroviruses was developed in BALB/c mice the first generation of which was infected with Coxsackie A18 virus in the neonatal period. Persistence of the virus was demonstrated in all females of the first generation tested and in 90.9% to 100% of the animals of the next two generations. Cytochemical analysis of the enzyme status of lymphocytes revealed reliable relationship between the depression of energetic metabolism enzymes and the activity of virus amplification in the animals under study. The correction of aerobic respiration in pregnant females by administration of a complex of energy metabolism substrates and cofactors was accompanied by a significant reduction of the virus infection activity in the females and their offsprings as well as by prevention of transplacental infection in some litters. The experimental model of vertical transmission of enteroviruses is proposed for use in the development of methods for prevention of congenital Coxsackie virus infection. The authors express their deep gratitude to the sponsor of the publication--NOVRUZ Co., Turkmenistan.

Animals↗

PubMedDate not supplied

Influence of different factors on bond strength of hybrid ionomers.

A new generation of filling materials, the hybrid-ionomer cements, has been introduced recently. In many clinical situations these hybrid ionomers may be an alternative to conventional glass-ionomer cements and resins bonded with dentin bonding agents. During the past years research has focused on factors influencing bond strength of dentin bonding systems, but there is not much knowledge about the bond strength of hybrid- and glass-ionomer filling materials under different conditions. Bond strengths of four hybrid ionomers, one conventional glass-ionomer cement, and one cermet cement were determined in superficial and deep, dry and moist dentin using a simplified pulp chamber model. All materials showed significantly higher bond strength to superficial compared to deep dentin. Moisture showed no significant influence on any material neither in deep nor in superficial dentin. Bond strengths of Fuji II LC, Variglass, and Vitremer were distinctly higher than those of the conventional glass-ionomer cement (Ketac-Fil) and the cermet cement (Ketac-Silver), while that of Photac-Fil was not significantly different. Ionomer samples failed cohesively in superficial dentin in over 60% of the samples. The bonding interfaces between Fuji II LC and Variglass and the treated dentin surface showed tags but no distinct hybrid layer. Bond strength is not only dependent on the pretreatment of the dentin, but also on the glass-ionomer resin composition of the material.

Acrylic Resins↗

PubMedDate not supplied

Pulsatile and nonpulsatile flows can be quantified in terms of energy equivalent pressure during cardiopulmonary bypass for direct comparisons.

The purpose of this study was to quantify and compare pulsatile and nonpulsatile pressure and flow waveforms in terms of energy equivalent pressure (EEP) during cardiopulmonary bypass in a neonatal piglet model. EEP is the ratio of the area under the hemodynamic power curve and the flow curve. Piglets, mean weight of 3 kg, were used in physiologic pulsatile pump (n = 7), pulsatile roller pump (n = 6), and nonpulsatile roller pump (n = 7) groups. Data (waveforms of the femoral artery pressure, pump flow, and preaortic cannula extracorporeal circuit pressure) were collected during normothermic cardiopulmonary bypass at 35 degrees C (15 minutes on-pump), before deep hypothermic circulatory arrest (pre-DHCA) at 18 degrees C, and after cold reperfusion and rewarming (post-DHCA) at 36 degrees C. The pump flow rate was 150 ml/kg/min in all three groups. During pulsatile perfusion, the pump rate was 150 bpm in both pulsatile groups. Although there was no difference in mean pressures in all groups, EEP and the percentage increase of pressure (from mean pressure to EEP) of mean arterial pressure and preaortic cannula extracorporeal circuit pressure were higher with pulsatile perfusion compared with nonpulsatile perfusion (p < 0.001). In particular, the physiologic pulsatile pump group produced significantly higher hemodynamic energy compared with the other groups (p < 0.001). These results suggest that pulsatile and nonpulsatile flows can be quantified in terms of EEP for direct comparisons, and pulsatile flow generates higher energy, which may be beneficial for vital organ perfusion during cardiopulmonary bypass.

Animals↗

PubMed1998

Balancing function of the masticatory muscles during incisal biting in two murid rodents, Apodemus speciosus and Clethrionomys rufocanus.

The functional significance of masticatory muscle direction was estimated using a mechanical model in two murid rodents: the Japanese field mouse (Apodemus speciosus) and the gray red-backed vole (Clethrionomys rufocanus). Theoretical analyses of the data suggest that a balancing mechanism among the muscle forces occurs during incisal power stroke. The activation of the large deep masseter in both murids results in marked tensile separation of two hemimandibles at the flexible mandibular symphysis. Activation of the internal pterygoid decreases this large tensile force at the symphysis more efficiently than other muscles. The lines of action of the deep masseter and internal pterygoid are aligned to produce such a balancing function in both species studied here. The resultant force generated by the deep masseter on both sides is opposite in direction to the reaction force at the lower incisor tip. Therefore, the large deep masseter forms an effective mandibular support mechanism when the reaction forces during biting push the mandible downward. Because of the area of insertion and the line of action, the posterior temporalis appears to have an important role in stabilizing the position of the mandibular condyle in the glenoid fossa during incisal biting.

Animals↗

PubMed1981

[Microwave hyperthermia: influence of blood flow and thermoregulation processes (author's transl)].

Various problems are encountered during production of local, deep-seated microwave hyperthermia, involving the technology of the irradiating system, and the complexity of heat transfer in living tissues. Before starting investigations on patients, preliminary studies were conducted on different models. Taking the influence of the blood flow into account, the thermal effects of microwaves were simulated on a numerical model, and a perfused phantom. These studies were completed by investigations in animals. The analysis of findings demonstrates that, in given conditions of irradiation, the temperature distribution is strongly dependent on blood flow. This means that the phantom models are only useful to evaluate the influence of the irradiation parameters and to develop and compare the generator-applicator systems, and that accurate planning of therapeutic trials requires in vivo studies on animals as well as on patients.

Animals↗

PubMed1990

Spatially-localized NMR spectroscopy employing an inhomogeneous surface-spoiling magnetic field gradient. 2. Surface coil experiments with multicompartment phantom and rat in vivo.

The use of inhomogeneous surface-spoiling magnetic field gradients for elimination of signal from surface lying regions of a sample was theoretically examined in the companion article (W. Chen and J.J.H. Ackerman, NMR Biomed. 3, 147-157 (1990)). Using the spoiling gradient coil design described therein, this article presents experimental verification of the feasibility of such an approach to enhanced spatial localization. Single coil mode 31P NMR surface coil interrogation of both a two compartment phantom and rat in vivo are shown to provide excellent suppression of surface lying regions with minimal degradation of signal from the deep lying region of interest. Both pulse-and-collect and spin echo sequences were highly efficient in concert with spoiling gradient periods of 0.5-2 ms and driving currents of 0.5-2 A. The use of a current-generated surface spoiling gradient offers a robust means to remove surface tissue signal contributions and can be implemented with a wide range of localizing pulse sequences and imaging protocols.

Animals↗

PubMed1975

[Formation of a generator of excitation in the gigantocellular nucleus of the medulla oblongata during disruption of inhibitory processes].

Neuronal activity in the gigantocellular nucleus after injection of tetanus toxin was studied on decerebrated cats. The toxin was used as a substance producing a deep and continuous suppression of inhibitory processes. The increase in the amplitude and rate of neuronal discharges, in the integral background and evoked activity as well as in the number of active neurons and that of neurons with burst activity was recorded in the "poisoned" nucleus. The enhanced activity in the investigated regions of the poisoned nucleus might be temporarily suppressed by a strong direct electrical shock and by glycin administrations to those regions. The obtained data indicate that a pool of neurons with disturbed inhibitory processes forms a generator of enhanced excitation. The mechanisms and characteristic features of the activity of such generators are discussed. The possibility of modelling neurological syndromes by production of similar generators in various parts of the central nervous system and their relation to the earlier described phenomenon of "dispatch station" are considered.

Animals↗

PubMed1992

Numerical phase algorithm for decompression computers and application.

Present generation decompression computers employ a simplified algorithm, limiting dissolved gas build-up in tissue and blood according to a method proposed by Haldane 80 years ago. Such a model works well for single dives, but is usually liberal and theoretically incomplete for multiple exposures within 24 hr spans. Using the critical phase hypothesis in a bubble model, we have extended the classical model of Haldane to multi-exposures. This model is discussed, and a decomputer algorithm described for multi-diving. The focus is permissible bubble excess, not just dissolved gas per se, with phase constraints affecting all tissues, fast and slow, and requiring a systematic lowering of repetitive tissue tensions. Deep repetitive and shallow multi-day exposures are impacted most by the procedure. Within nucleation theory deeper-than-first dives are also treated. A set of multi-diving fractions, xi, accounting for micronuclei excitation and regeneration, reduced bubble elimination in repetitive activity, and coupled effects on tissue tension, are proposed, with xi representing a set of multiplicative factors (less than one) applied to critical tissue tensions for multi-exposures. These factors affect repetitive activity over short time spans, deeper-than-previous and continuous multi-day activities, compared to standard computer software, and are easily encoded into existing decompression meters, potentially extending their range and flexibility over exposure regimes.

Algorithms↗

PubMedDate not supplied

A prototype epithermal neutron beam for boron neutron capture therapy.

An epithermal neutron beam has been designed and tested at the Georgia Institute of Technology's 5-MW Research Reactor. The prototype facility consists of aluminum and sulfur disks in a tangential beam port for fast neutron filtration. A cadmium sheet at the port exit removes the thermal neutrons from the transmitted beam, leaving an intensely epithermal neutron beam spanning five energy decades, each contributing to the flux demanded by boron neutron capture therapy. The thermal neutron flux generated by the incident epithermal neutrons in a polyethylene head phantom peaks at a depth of 3 cm and remains above the incident thermal flux to a 7-cm depth. The beam thus provides the penetration required for treating deep-seated gliomas. Photon contamination in the prototype facility is high, and a number of basic modifications are proposed for reducing it to safer levels.

Boron↗

PubMedDate not supplied

Orthopaedic nursing research priorities: a replication and extension.

PURPOSE: This study identified current orthopaedic nursing research priorities that should be investigated to advance the practice of orthopaedic nursing. The study was accomplished by the National Association of Orthopaedic Nurses' (NAON) Research Committee via a national survey of selected NAON members. DESIGN: A descriptive design was used to determine research priorities. SAMPLE: The sample consisted of a random sample of 133 NAON members. The sample was stratified for either graduate degrees (> or = master's), other than a graduate degree (< or = bachelor's) (to insure representation from "frontline" practicing nurses), and registrants in the NAON Researcher Database and recipients of NAON Foundation or American Academy of Orthopaedic Surgeons (AAOS)/NAON grants. METHOD: A three round Delphi survey technique was used to build consensus by systematically generating, synthesizing, and analyzing opinions of a group of experts while maintaining confidentiality of the individuals. MAIN RESEARCH CLASSIFICATIONS: Nursing research priorities, Delphi method, Orthopaedic nursing. FINDINGS: The nine target research questions for orthopaedic nursing identified as high priority were grouped into the following categories: patient acuity, care delivery models, staffing issues, patient complications, pain management (in the elderly and those with altered mental status), and patient mobility. These research priority items are intended to direct the orthopaedic nurse researcher to study specific questions within these categories. CONCLUSION: Results reflect the dramatic changes occurring in orthopaedic nursing practice. Research priorities reveal the need for more research on pain and patient complications (e.g., deep vein thrombosis (DVT)) despite a preponderance of existing, published research on these topics. IMPLICATIONS FOR NURSING RESEARCH: This study identified target research questions for orthopaedic nursing. These questions may be used by orthopaedic nurses to develop nursing research proposals as well as collaborative research endeavors with other members of the orthopaedic health care team. An ongoing and wider dissemination of results of existing research to the NAON membership needs to be implemented.

Delphi Technique↗

PubMed1997

A generic morphological model of the anatomic variability in the m. flexor digitorum profundus, m. flexor pollicis longus and mm. lumbricales complex.

In the present study a generic model is presented of the anatomic variability in the muscle group formed by the m. flexor digitorum profundus, m. flexor pollicis longus and mm. lumbricales. This model provides a hypothesis about the structural causes of the frequent interdependence of tendons and muscle bellies in this muscle group. The model considers the muscle group as composed of two simple elementary building blocks: the monogastric contractile units of the FDP-FPL, and the digastric contractile elements of the lumbrical, and shows that these units can be assembled into complex entities, to which in reality a third structural element, the synovial membranes, not discussed in the present paper, adds a further complexity. The model allows to generate homologues of the existing anatomical variants, which are illustrated by typical dissection results. The present study should be of relevance to the morphologist, embryologist, surgeon, and musician/pedagogue. To the morphologist, it presents an alternative method of description or understanding of anatomic variability, based on (i) the 'atomary' concept that the anatomic structure is assembled from simple basic elements, and (ii) the local spatial constraints. To the embryologist, it raises the question to what degree the 'atomary' anatomical components of this model, which describes the macroscopic anatomy of the muscle group in detail, have an embryological basis. To the surgeon, the study presents detailed information about the scope of the variability in the deep flexor group, and the nature of its intertendinous connections. To the musician/pedagogue, it presents a visual illustration of the congenital interdependence of the muscles and tendons of an important finger motor group, as a possible cause of lack in finger independence which may hamper a fluent instrumental technique.

Dissection↗