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PubMed2002

Future of technology to augment patient support in hospitals.

This chapter explores the potential of using computer technology to support and augment psychotherapeutic interventions in hospitals, communities and homes. We describe two applications piloted at Children's Hospital Boston. The first pilot explored how patients with pediatric heart disease used the Storytelling Agent Generation Environment (SAGE) computer program to create interactive storytellers and share their personal stories. The second involved youngsters on hemodialysis for end stage renal disease using the Zora graphical multi-user environment to create a virtual city and form a therapeutic virtual community. In this chapter we show how computer technology can be used to help patients explore their identity, cope with their illness and provide mutual support and interaction. We also present design recommendations for future interventions of this kind.

Adaptation, Psychological↗

PubMed2004

[The new frontier of distance learning: the climate of the virtual lecture hall].

INTRODUCTION: The recent ECM standards outline new dilemmas not only under an economic and/or management point of view, but even under a teaching and procedural aspect. FAD seems to solve problems, allowing us to arrange courses according to our demand, but it still doesn't solve all the issues, for example, the teaching-learning model. PROBLEM ANALYSIS: The article starts analysing formative procedures to reflect in an interactive logic about object and subject in FAD, to set a dynamic learning process in a knowledge management viewpoint, where the user is fully aware that he/she will be divided from his/her tutor and from his/her colleagues in the virtual classroom. The learning environment is a crucial circumstance to assure full functionality of the course and to make the FAD experience a valuable one and repeatable in the future for different courses. CONCLUSIONS: FAD is an asynchronous activity and for this it could be moulded according to the single user's requirements. It needs a relational dimension to facilitate the learning process through the strategy sharing of problem solving.

Education, Distance↗

PubMed2005

Assessment of brain activities in immersive environments.

The primary goal of this study was to establish an objective baseline for subjects who participated in a study in an immersed environment created for the virtual reality therapy (VRT) situation. Since the effects of VRT on the subjects treated for neurosis have traditionally been measured by subjective measurements, there is a need to include objective measures. This will improve and validate the effectiveness of VRT. Fifteen college students participated in this study. Specifically, the researchers measured the activity of the subjects' brainwaves in response to the VRT using EEG technology. The preliminary data indicated that, in most cases, subjects had a decline in brain wave activity between what is deemed a normal / baseline brain activity and the brainwave activity recorded when they were when they were connected to the virtual reality equipment and under influence of an immersive scene. In rare instances, there were some subjects that showed extreme increases in brain activities. In addition, the data indicated that, in most cases, subjects are more relaxed while under the immersive influence with respect to brain activities than those that are not.

Brain↗

PubMed2003

Quantitative cell biology with the Virtual Cell.

Cell biological processes are controlled by an interacting set of biochemical and electrophysiological events that are distributed within complex cellular structures. Computational models, comprising quantitative data on the interacting molecular participants in these events, provide a means for applying the scientific method to these complex systems. The Virtual Cell is a computational environment designed for cell biologists, to facilitate the construction of models and the generation of predictive simulations from them. This review summarizes how a Virtual Cell model is assembled and describes the physical principles underlying the calculations that are performed. Applications to problems in nucleocytoplasmic transport and intracellular calcium dynamics will illustrate the power of this paradigm for elucidating cell biology.

Active Transport, Cell Nucleus↗

PubMed2004

Virtual-reality-based laparoscopic surgical training: the role of simulation fidelity in haptic feedback.

Although there have been significant advances in the development of virtual-reality-based surgical simulations, there remain fundamental questions concerning the fidelity required for effective surgical training. A dual-station experimental platform was built for the purpose of investigating these fidelity requirements. Analogous laparoscopic surgical tasks were implemented on a virtual station and a real station, with the virtual station modeling the real environment with various degrees of fidelity. After measuring the subjects' initial performance on the real station, different groups of subjects were trained on the virtual station under a variety of conditions and finally tested on the real station. Experiments involved bimanual pushing and cutting tasks on a nonlinear elastic object. The results showed that force feedback results in significantly improved training transfer as compared to training without force feedback. The training effectiveness of a linear approximation model was approximately the same as that of a more accurate nonlinear model.

Analysis of Variance↗

PubMed1997

The virtual hand. The Pulvertaft Prize Essay for 1996.

Virtual reality technologies are now at a stage in which the various disciplines can be brought together to construct a virtual human hand. Devices can be constructed to record multiple joint positions accurately in clinical environments. Joint prostheses may be tested virtually before undergoing clinical trials, albeit in a simple way at present, but may eventually be incorporated into a virtual model of the hand and driven by goniometric gloves. This will allow more detailed analyses of implant in situ behaviour. These exciting developments will provide a huge advance in our understanding of the functions of the real hand and also a potential way of assessing outcomes in a simple and repeatable fashion. We are on the edge of a new era in hand surgery when the computer scientist, biomechanic, control engineer, hand therapist and surgeon will be able to alternate between the virtual and the real world in producing better outcomes for patients.

Biomechanical Phenomena↗

PubMed2004

Validation of dynamic heart models obtained using non-linear registration for virtual reality training, planning, and guidance of minimally invasive cardiac surgeries.

Current minimally invasive techniques for beating heart surgery are associated with three major limitations: the shortage of realistic and safe training methods, the process of selecting port locations for optimal target coverage from X-rays and angiograms, and the sole use of the endoscope for instrument navigation in a dynamic and confined 3D environment. To supplement the current surgery training, planning and guidance methods, we continue to develop our Virtual Cardiac Surgery Planning environment (VCSP) -- a virtual reality, patient-specific, thoracic cavity model derived from 3D pre-procedural images. In this work, we create and validate dynamic models of the heart and its components. A static model is first generated by segmenting one of the image frames in a given 4D data set. The dynamics of this model are then extracted from the remaining image frames using a non-linear, intensity-based registration algorithm with a choice of six different similarity metrics. The algorithm is validated on an artificial CT image set created using an excised porcine heart, on CT images of canine subjects, and on MR images of human volunteers. We found that with the appropriate choice of similarity metric, our algorithm extracts the motion of the epicardial surface in CT images, or of the myocardium, right atrium, right ventricle, aorta, left atrium, pulmonary arteries, vena cava and epicardial surface in MR images, with a root mean square error in the 1 mm range. These results indicate that our method of modeling the motion of the heart is easily adaptable and sufficiently accurate to meet the requirements for reliable cardiac surgery training, planning, and guidance.

Algorithms↗

PubMed2002

The sono-degradation of phenanthrene in an aqueous environment.

Polynuclear aromatic hydrocarbon (PAH) contamination has spread throughout the globe with background levels now found in virtually all sections of the ecosystem and environment. The mutagenic and/or carcinogenic properties attributed to many of these compounds, and frequency of occurrence and concentration in the environment, has driven research into safe methods of removing contamination, whilst avoiding the use of harmful solvents or the formation of even more hazardous compounds. Ultrasound is currently used in industry and research to propagate and accelerate chemical reactions, opening reaction pathways which otherwise would not be observed. In the study of the degradation of PAHs through ultrasonic irradiation, the breakdown of an aqueous solution of phenanthrene in a sonochemical reactor utilising a 30 kHz probe system, operating in batch mode, has been investigated. The phenanthrene molecule was studied and used as a model PAH molecule. It was chosen due to the structural similarities to many of the higher order PAHs currently recognised as being hazardous to health. The influence of several parameters on the degradation of phenanthrene are reported (power ultrasound energy, temperature and light). Qualitative analysis using HPLC and quantitative analysis using UV/Vis photo-spectrometry confirmed that a 88% reduction in the peak observed phenanthrene concentration was achieved over 240 min of sonocation. Whilst there was the potential for the formation of recalcitration and rearrangement products, no higher order PAHs were observed and a 80% reduction in total monitored UV fluorescence and hence, aromaticity/conjugation, was observed.

Journal Article↗

PubMedDate not supplied

Novel 2D fingerprints for ligand-based virtual screening.

This paper describes the development of a set of new 2D fingerprints for the purposes of virtual screening in a pharmaceutical environment. The new fingerprints are based on established ones: the changes in their design included the introduction of overlapping pharmacophore feature types, feature counts for pharmacophore and structural fingerprints, as well as changes in the resolution in property description for property fingerprints. The effects of each of these changes on virtual screening performance were monitored using two types of training sets, emulating different stages in the drug discovery process. The results demonstrate that these changes all lead to an improvement in virtual screening performance.

Chemistry↗

PubMed2005

[System design of small intellectualized ultrasound hyperthermia instrument in the LabVIEW environment].

Small-scale intellectualized medical instrument has attracted great attention in the field of biomedical engineering, and LabVIEW (Laboratory Virtual Instrument Engineering Workbench) provides a convenient environment for this application due to its inherent advantages. The principle and system structure of the hyperthermia instrument are presented. Type T thermocouples are employed as thermotransducers, whose amplifier consists of two stages, providing built-in ice point compensation and thus improving work stability over temperature. Control signals produced by specially designed circuit drive the programmable counter/timer 8254 chip to generate PWM (Pulse width modulation) wave, which is used as ultrasound radiation energy control signal. Subroutine design topics such as inner-tissue real time feedback temperature control algorithm, water temperature control in the ultrasound applicator are also described. In the cancer tissue temperature control subroutine, the authors exert new improvments to PID (Proportional Integral Differential) algorithm according to the specific demands of the system and achieve strict temperature control to the target tissue region. The system design and PID algorithm improvement have experimentally proved to be reliable and excellent, meeting the requirements of the hyperthermia system.

Algorithms↗

PubMed1998

Knowing where things are parahippocampal involvement in encoding object locations in virtual large-scale space.

The involvement of the medial temporal-lobe region in allocentric mapping of the environment has been observed in human lesion and functional imaging work. Cognitive models of environmental learning ascribe a key role to salient landmarks in representing large-scale space. In the present experiments we examined the neural substrates of the topographical memory acquisition process when environmental landmarks were more specifically identifiable. Using positron emission tomography (PET), we measured regional cerebral blood flow changes while normal subjects explored and learned in a virtual reality environment. One experiment involved an environment containing salient objects and textures that could be used to discriminate different rooms. Another experiment involved a plain empty environment in which rooms were distinguishable only by their shape. Learning in both cases activated a network of bilateral occipital, medial parietal, and occipitotemporal regions. The presence of salient objects and textures in an environment additionally resulted in increased activity in the right parahippocampal gyrus. This region was not activated during exploration of the empty environment. These findings suggest that encoding of salient objects into a representation of large-scale space is a critical factor in instigating parahippocampal involvement in topographical memory formation in humans and accords with previous studies implicating parahippocampal areas in the encoding of object location.

Adult↗

PubMed2004

Frames of reference in mobile augmented reality displays.

In 3 experiments, the authors investigated spatial updating in augmented reality environments. Participants learned locations of virtual objects on the physical floor. They were turned to appropriate facing directions while blindfolded before making pointing judgments (e.g., "Imagine you are facing X. Point to Y"). Experiments manipulated the angular difference between the learning heading and the imagined heading and between the actual heading and the imagined heading. The effect of actual-imagined on pointing latency was observed for naive users but not for users with brief training or instructions concerning the fact that objects can move with body movements. The results indicated that naive users used an environment-stabilized reference frame to access information arrays, but with experience and instruction the nature of the representation changed from an environment stabilized to a body stabilized reference frame.

Environment↗

PubMed2003

Knowledge management system for benchmarking performance indicators using statistical process control (SPC) and Virtual Instrumentation (VI).

Healthcare is ever changing environment and with the Joint Commission for the Accreditation of Hospital Organization (JCAHO) emphasis on quality improvement during the past several years, and the cost-focused healthcare reforms of the 1990s, benchmarking with peer comparison, and more recently benchmarking against competitors, has taken on a new emphasis. All acute healthcare organizations accredited by JCAHO now require participation in a program titled ORYX, which is designed to use comparisons with other organizations and promote national benchmarks. The knowledge management system designed assists clinical engineering department to convert vast amounts of available data into information, which is ultimately transformed into knowledge to enable better decision-making. The systems assist in using the data as a comparison tool, to compare the performance internally and also compare performance with peer organizations using the same measures within the same measurement system. Collectively, these applications support better, faster data-driven decisions. This tool provides fast and easy access to financial and quality metrics to clinical engineering department managers, which increases their ability to perform sophisticated analysis to develop accurate models and forecasts, and make timely, data driven decisions. The project also provides a platform by means of which clinical engineering departmental procedures, data, and methods can be assessed and shared among institutions.

Artificial Intelligence↗

PubMed1993

First structure of a snake venom metalloproteinase: a prototype for matrix metalloproteinases/collagenases.

Adamalysin II, a 24 kDa zinc endopeptidase from the snake venom of Crotalus adamanteus, is a member of a large family of metalloproteinases isolated as small proteinases or proteolytic domains of mosaic haemorrhagic proteins from various snake venoms. Homologous domains have recently been detected in multimodular mammalian reproductive tract proteins. The 2.0 A crystal structure of adamalysin II reveals an ellipsoidal molecule with a shallow active-site cleft separating a relatively irregularly folded subdomain from the calcium-binding main molecular body composed of a five-stranded beta-sheet and four alpha-helices. The folding of the peptide fragment containing the zinc-binding motif HExxHxxGxxH bears only a distant resemblance to thermolysin, but is identical to that found in astacin, with the three histidines and a water molecule (linked to the glutamic acid) likewise constituting the zinc ligand; adamalysin II lacks a fifth (tyrosine) zinc ligand, however, leaving its zinc ion tetrahedrally co-ordinated. Furthermore, adamalysin II and astacin share an identical active-site basement formed by a common Metturn. Due to their virtually identical active-site environment and similar folding topology, the snake venom metalloproteinases (hitherto called adamalysins) and the astacins (and presumably also the matrix metalloproteinases/mammalian collagenases and the Serratia proteinase-like large bacterial proteinases) might be grouped into a common superfamily with distinct differences from the thermolysin family.

Amino Acid Sequence↗

PubMed2005

PRIME: a graphical interface for integrating genomic/proteomic databases.

Data mining, finding and integration of information about proteins of interest, is an essential component in modern biological and biomedical research. Even when focusing on a single organism and only on a small number of proteins, there are often dozens fo data sources containing relevant information. We are developing PRIME, a protein information environment, to serve as a virtual central database which integrates distributed heterogeneous information about proteins (linked by common identifier). PRIME has powerful capabilities to visualize all kinds of protein annotation in specialized views. These views can be displayed side by side at the same time and can be synchronized in order to show simultaneously different aspects of identical proteins. These features allow a quick and comprehensive overview of properties of single proteins or protein sets.

Computational Biology↗

PubMed2006

Intracorporeal rectal stapling following laparoscopic total mesorectal excision: overcoming a challenge.

BACKGROUND: Division of the rectum following total mesorectal excision (TME) using intracorporeal stapling devices is technically difficult due to their width and limited roticulation. More than one cartridge is often required and resultant wedging of the stump may be associated with an appreciable leak rate. METHODS: Three-dimensional reconstruction was performed of CT and MRI images from the lower abdomen of six patients undergoing laparoscopic TME using the Amira software environment. The stapling device was virtually reconstructed by in-house developed software, superimposed over the point of division of the rectum and the site of skin entry identified. RESULTS: The 45 degrees angulation of available roticulating stapling devices precludes perpendicular division of the rectum following laparoscopic TME. The optimal angulation for transverse rectal stapling varied between 62 degrees and 68 degrees . CONCLUSION: A roticulating stapler with minimum angulation of 65 degrees would achieve transverse division of the rectum following laparoscopic TME.

Aged↗

PubMed1997

The epidemiology of disease transmission.

As inhabitants of the planet Earth, we live in a veritable sea of microorganisms. Virtually every aspect of our environment is heavily populated with different forms of microbial life. From the air we breathe to the food we eat, our daily existence is in the direct presence of literally billions of microorganisms.

Communicable Disease Control↗

PubMed1997

Site-directed spin-labeling study of the structure and subunit interactions along a conserved sequence in the alpha-crystallin domain of heat-shock protein 27. Evidence of a conserved subunit interface.

Site-directed spin-labeling (SDSL) was used to investigate the secondary structure, solvent accessibility, and tertiary and quaternary interactions along the sequence located between residues 133 and 144 in the alpha-crystallin domain of human heat-shock protein 27 (HSP 27). The sequence is conserved among mammalian sHSP and shows similarity to the region of highest homology between alpha A- and alpha B-crystallins. Eleven sequential single cysteine mutants were prepared and reacted with a sulfhydryl-specific spin-label. The accessibilities of attached nitroxide side chains to a paramagnetic probe in the aqueous solution were determined. Spectral line shapes were analyzed in terms of side-chain mobility and spatial proximity to nearby nitroxides. The sequence-specific mobilities and accessibilities varied with a period of 2, consistent with the presence of a beta-strand along the sequence. At even sites, the nitroxide environment is highly ordered with virtually no accessibility to the hydrophilic probe, indicating that one face of the strand is buried. Furthermore, spin-spin interactions between nitroxides in the oligomeric structure strongly suggest that equivalent strands from different subunits are in close spatial proximity. These structural characteristics are remarkably similar to those of the equivalent sequence in alpha A-crystallin [Berengian, A. R., Bova, M. P., and Mchaourab, H. S. (1997) Biochemistry 36, 9951-9957]. In both proteins, a beta-strand spans the sequence and is located at a subunit interface, indicating that one set of interactions between subunits, and its associated symmetry, is conserved. This is the first report of sequence-specific structural similarity between alpha A-crystallin and HSP 27 and the first identification of a conserved secondary structural element in the alpha-crystallin domain.

Amino Acid Sequence↗