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PubMed2004

Planning, implementation and optimization of future space missions using an immersive visualization environment (IVE) machine.

Beginning in 1995, a team of 3-D engineering visualization experts assembled at the Lockheed Martin Space Systems Company and began to develop innovative virtual prototyping simulation tools for performing ground processing and real-time visualization of design and planning of aerospace missions. At the University of Colorado, a team of 3-D visualization experts also began developing the science of 3-D visualization and immersive visualization at the newly founded British Petroleum (BP) Center for visualization, which began operations in October, 2001. BP acquired ARCO in the year 2000 and awarded the 3-D flexible IVE developed by ARCO (beginning in 1990) to the University of Colorado, CU, the winner in a competition among 6 Universities. CU then hired Dr. G. Dorn, the leader of the ARCO team as Center Director, and the other experts to apply 3-D immersive visualization to aerospace and to other University Research fields, while continuing research on surface interpretation of seismic data and 3-D volumes. This paper recounts further progress and outlines plans in Aerospace applications at Lockheed Martin and CU.

Astronauts↗
PubMed1980

Raman and 19F(1H) nuclear Overhauser evidence for a rigid solution conformation of Escherichia coli 5-fluorouracil 5S ribonucleic acid.

Escherichia coli cells grown on a medium containing 5-fluorouracil (FU) produce 5S RNA whose uracil residues are approximately 80% replaced by FU. The Raman spectra of native and FU-5S RNA are very similar, confirming similar solution conformations for the two species and a highly base-stacked structure in solution. The 254-MHz 19F NMR spectrum of FU-5S RNA shows that the 20-odd FU residues reside in at least ten distinct chemical environments, suggesting a highly ordered structure. Comparison of theoretical and experimental 19F(1H) nuclear Overhauser enhancements demonstrates definitively that virtually all the labeled uracils are bound to a rigid macromolecular frame, with a rotational correlation time of about 19 ns or longer. Since these uracils are widely distributed throughout the nucleotide primary sequence, it may be concluded that the entire FU-5S RNA solution structure is relatively rigid, in agreement with the most recently proposed "cloverleaf" secondary structural model for native prokaryotic 5S RNA.

Escherichia coli↗
PubMedDate not supplied

Enzymatic catalysis of formation of Z-aspartame in ionic liquid - An alternative to enzymatic catalysis in organic solvents.

We present the first report of enzymatic catalysis in an ionic liquid. The virtually nonexistent vapor pressure makes ionic liquids an exciting new alternative for enzyme-catalyzed syntheses in environmentally friendly environments. Z-aspartame was synthesized in a thermolysin-catalyzed reaction of carbobenzoxy-L-aspartate and L-phenylalanine methyl ester hydrochloride in 1-butyl-3-methylimidazolium hexafluorophosphate (BP6). Ionic liquids such as BP6 are thermally stable and have a remarkable range of temperatures over which they remain liquid (300 degrees C). With an initial rate of 1.2 +/- 0.1 nmol min(-)(1) mg(-)(1), we observed a competitive rate in comparison to that of enzymatic synthesis in organic solvent. Additionally, the enzyme exhibits outstanding stability, which would normally require immobilization.

Aspartame↗
PubMed2004

Synthesis, structure and comparison of the DNA cleavage ability of metal complexes M(II)L with the N-(2-ethoxyethanol)-bis(2-picolyl)amine ligand L (M = Co, Ni, Cu and Zn).

Complexes of a N,N-bis(2-picolyl)amine (bpa) derivative with a pendant ethoxyethanol side chain (bpa(CH2)2O(CH2)2OH) (1) with late divalent transition metal ions Co(II), Ni(II), Cu(II) and Zn(II) have been studied. All complexes, [[bpa(CH2)2O(CH2)2OH]Co(NO3)](NO3) (1Co), [[bpa(CH2)2O(CH2)2OH]Ni(NO3)](NO3) (1Ni), [[bpa(CH2)2O(CH2)2OH]Cu(H2O)(NO3)](NO3) (1Cu) and [[bpa(CH2)2O(CH2)2OH]Zn(NO3)](NO3) (1Zn), were comprehensively characterized and their X-ray single crystal structures have been determined. The complexes show hexacoordinated geometries, in which 1 acts as a tetradentate (1Cu) or pentadentate (1Co, 1Ni and 1Zn) ligand. DNA cleavage experiments have been performed on supercoiled double stranded DNA plasmids in order to compare the cleavage efficiency of all four metals in the same ligand environment of 1. In this assay, 1Co and 1Cu showed the highest cleavage efficiency, whereas 1Ni and 1Zn were virtually inactive. Quantification of the gel electrophoresis bands showed that more than 80% of the plasmid has suffered at least one single strand cut in the case of 1Cu, and about 50% of the plasmid was nicked by 1Co. The differential cleavage activity is discussed in relation to the structural findings and a mechanism is proposed for 1Cu.

Amines↗
PubMed1994

Sleep and arousal, synchrony and independence, among mothers and infants sleeping apart and together (same bed): an experiment in evolutionary medicine.

Although solitary sleeping in infancy is a very recent custom, limited to Western industrialized societies, and most contemporary people practice parent-infant co-sleeping, virtually all laboratory research on sleep in human infants assumes that solitary infant sleep is the normal and desirable environment. We have used evolutionary and developmental data to challenge this view. We suggest that co-sleeping provides a sensory-rich environment which is the more appropriate environment in which to study infant sleep. In addition, two preliminary, in-laboratory, polygraphic investigations of mother-infant co-sleeping are reported in normal infants, within the peak age range for sudden infant death syndrome (SIDS). Five mother-infant pairs co-slept one night in the first study; in the second, three additional pairs slept separately for two nights and co-slept the third consecutive night. The results suggest that co-sleeping is associated with enhanced infant arousals and striking temporal overlap (synchronicity) in infant and maternal arousals, and that, possibly as a result, co-sleeping mothers and infants spend more time in the same sleep stage or awake condition. The implications of the hypothesis and preliminary results for research on the normal development of infant sleep and on SIDS are discussed.

Female↗
PubMed2001

Multilocus sequence typing system for Campylobacter jejuni.

The gram-negative bacterium Campylobacter jejuni has extensive reservoirs in livestock and the environment and is a frequent cause of gastroenteritis in humans. To date, the lack of (i) methods suitable for population genetic analysis and (ii) a universally accepted nomenclature has hindered studies of the epidemiology and population biology of this organism. Here, a multilocus sequence typing (MLST) system for this organism is described, which exploits the genetic variation present in seven housekeeping loci to determine the genetic relationships among isolates. The MLST system was established using 194 C. jejuni isolates of diverse origins, from humans, animals, and the environment. The allelic profiles, or sequence types (STs), of these isolates were deposited on the Internet (http://mlst.zoo.ox.ac.uk), forming a virtual isolate collection which could be continually expanded. These data indicated that C. jejuni is genetically diverse, with a weakly clonal population structure, and that intra- and interspecies horizontal genetic exchange was common. Of the 155 STs observed, 51 (26% of the isolate collection) were unique, with the remainder of the collection being categorized into 11 lineages or clonal complexes of related STs with between 2 and 56 members. In some cases membership in a given lineage or ST correlated with the possession of a particular Penner HS serotype. Application of this approach to further isolate collections will enable an integrated global picture of C. jejuni epidemiology to be established and will permit more detailed studies of the population genetics of this organism.

Alleles↗
PubMedDate not supplied

Helicobacter pylori: the versatile pathogen.

Helicobacter pylori is a curvilinear motile gram-negative bacillus which is now recognized as the principal cause of type B gastritis, duodenal ulcer, gastric ulcer and MALT lymphoma. There is also a high degree of association between H. pylori gastritis and gastric carcinoma and non-Hodgkin's lymphoma of the stomach. H. pylori infection of the stomach is the most frequent chronic infection in the world. H. pylori is an extraordinary pathogen with virtually unrivaled versatility. The organism possesses the capacity to colonize and prosper in the hostile acidic gastric lumen, an environment in which other microorganisms cannot survive. H. pylori contains and expresses an assortment of proinflammatory biomolecules. H. pylori also stimulates host cells to release proinflammatory substances which participate in the initiation and perpetuation of inflammation and tissue injury. H. pylori elaborates a potent urease and a variety of other enzymes necessary for colonization and expression of the organism's pathogenicity. H. pylori is usually acquired in childhood, believed usually by fecal-oral transmission. The principal lesion induced by H. pylori is type B gastritis, which begins as acute inflammation involving the antrum. Type B gastritis then extends to the entire stomach with gradual progression to chronic gastritis and variable degrees of gastric mucosal atrophy. Much now is known but much more remains to be learned about H. pylori and the diseases which this extraordinary pathogen produces.

Adult↗
PubMed2005

Spatial exploration-induced Arc mRNA and protein expression: evidence for selective, network-specific reactivation.

The immediate-early gene Arc is transcribed in neurons that are part of stable neural networks activated during spatial exploratory behaviors. Arc protein has been demonstrated to regulate AMPA-type glutamate receptor trafficking by recruiting endosomal pathways, suggesting a direct role in synaptic plasticity. The purpose of the present study is to examine the fidelity of Arc mRNA translation and the temporal dynamics of behaviorally induced Arc protein expression after rats explore a novel environment. These experiments reveal two waves of Arc protein expression after a single exploration session. In the initial wave, virtually all cells that express Arc mRNA in the hippocampus and parietal cortex also express Arc protein, indicating, at a cellular level, that mRNA transcription and translation are closely correlated from 30 min to 2 h in hippocampal CA and parietal neurons. A second wave of protein expression spans the interval from 8 to 24 h and is also remarkably specific to cells active in the original behavior-induced network. This second wave is detected in a subset of the original active network and displays the novel property that the proportions of Arc-positive neurons become correlated among regions at 24 h. This suggests that the second expression wave is driven by network activity, and the stabilization of circuits reflecting behavioral experience may occur in temporally discrete phases, as memories become consolidated. This is the first demonstration of network-selective translational events consequent to spatial behavior and suggests a role for immediate-early genes in circuit-specific, late-phase synaptic biology.

Animals↗
PubMedDate not supplied

Image-navigated endoscopic surgery: introduction of the face-mounted display system with picture-in-picture capabilities.

BACKGROUND/AIMS: The face-mounted display system with picture-in-picture capabilities was evaluated for clinical usefulness in endoscopic surgery. METHODOLOGY: The device mounts two crystal liquid color panels, being shaped like a pair of glasses. It can provide us with an ultra-large virtual screen of the endoscopic view. Furthermore, a picture-in-picture capability can materialize a multi-image environment. Twenty-five patients were enrolled in this study. RESULTS: The view obtained by the surgeon consisted of the FMD screen of the upper two-thirds and the direct view of the lower one-third. The surgeon could concentrate more on the procedure, because he could face the target organ regardless of the display position. No complications attributable to the device were encountered. With a multi-image environment, endoscopic procedure was executed without taking one's eyes off the operative field. CONCLUSIONS: The face-mounted display system will conduct us to another sphere of endoscopic surgery, i.e., an image-navigated endoscopic surgery.

Cholecystectomy, Laparoscopic↗
PubMedDate not supplied

["... and found no shade". Coping processes of patients with erythropoietic protoporphyria].

Coping with disease was studied in a group of ten persons suffering from erythropoietic protoporphyria (EPP), a chronic congenital metabolic disorder that manifests itself in extreme sensitivity to ultraviolet light. Sufferers experienced medical prophylaxis as ineffective or counterproductive. The BEFO technique (Berner Bewältigungsformen BEFO, 3 dimensions, 27 categories) was used in assessing the coping strategies. The sufferers' interviews were evaluated on the basis of transcripts. Stressors and respective coping strategies were defined and analysed for each person individually. Sufferers are confronted with their disease virtually every day. For each stressor the set of strategies tends to be specific either to the disease, the environment or it may reflect personality traits. Most of the sufferers did not develop an effective mode of adaptive behavior, i.e. coping with the pain/stigma dilemma, until they passed their third decade. While it undeniably presents an intense personal challenge, coping with disease must be seen to include major societal aspects as well.

Adaptation, Psychological↗
PubMed2003

Dynamic deformation of elastic organ model and the VR cockpit for virtual surgery and tele-surgery.

This paper describes a deformable organ model suited for a real-time surgical simulation system. This proposed organ model allows us to perform surgical maneuvers such as pressing, pinching, various incisions, resection and to show the deformation of the inner structures such as blood vessels on our system. At the same time, we have been developing a VR cockpit suited for virtual surgery and tele-surgery. Using our cockpit, our system allows us to provide the users with an environment closely resembling the open surgery situation.

Computer Simulation↗
PubMed1999

Growing crops for space explorers on the moon, Mars, or in space.

An option in the long-duration exploration of space, whether on the Moon or Mars or in a spacecraft on its way to Mars or the asteroids, is to utilize a bioregenerative life-support system in addition to the physicochemical systems that will always be necessary. Green plants can use the energy of light to remove carbon dioxide from the atmosphere and add oxygen to it while at the same time synthesizing food for the space travelers. The water that crop plants transpire can be condensed in pure form, contributing to the water purification system. An added bonus is that green plants provide a familiar environment for humans far from their home planet. The down side is that such a bioregenerative life-support system--called a controlled environment life-support system (CELSS) in this paper--must be highly complex and relatively massive to maintain a proper composition of the atmosphere while also providing food. Thus, launch costs will be high. Except for resupply and removal of nonrecycleable substances, such a system is nearly closed with respect to matter but open with respect to energy. Although a CELSS facility is small compared to the Earth's biosphere, it must be large enough to feed humans and provide a suitable atmosphere for them. A functioning CELSS can only be created with the help of today's advanced technology, especially computerized controls. Needed are energy for light, possibly from a nuclear power plant, and equipment to provide a suitable environment for plant growth, including a way to supply plants with the necessary mineral nutrients. All this constitutes the biomass production unit. There must also be food preparation facilities and a means to recycle or dispose of waste materials and there must be control equipment to keep the facility running. Humans are part of the system as well as plants and possibly animals. Human brain power will often be needed to keep the system functional in spite of the best computer-driven controls. The particulars of a CELSS facility depend strongly on where it is to be located. The presence of gravity on the Moon and Mars simplifies the design for a facility on those bodies, but a spacecraft in microgravity is a much more challenging environment. One problem is that plants, which are very sensitive to gravity, might not grow and produce food in the virtual absence of gravity. However, the experience with growing super-dwarf wheat in the Russian space station Mir, while not entirely successful because of the sterile wheat heads, was highly encouraging. The plants grew well for 123 days, producing more biomass than had been produced in space before. This was due to the high photon flux available to the plants and the careful control of substrate moisture. The sterile heads were probably due to the failure to remove the gaseous plant hormone, ethylene, from the Mir atmosphere. Since ethylene can easily be removed, it should be possible to grow wheat and other crops in microgravity with the production of viable seeds. On the ground Biosphere-2 taught us several lessons about the design and construction of a CELSS facility, but Bios-3 came much closer to achieving the goals of such a facility. Although stability was never completely reached, Bios-3 was much more stable than Biosphere-2 apparently because every effort was made to keep the system simple and to use the best technology available to maintain control. Wastes were not recycled in Bios-3 except for urine, and inedible plant materials were incinerated to restore CO2 to the atmosphere. Since much meat (about 20% of calories) was imported, closure in the Bios-3 experiments was well below 100%. But then, a practical CELSS on the Moon might also depend on regular resupply from Earth. Several important lessons have been learned from the CELSS research described in this review.

Agriculture↗
PubMed2005

Mixed messages: a qualitative study of the meanings and context of high school students' tobacco use in Turkey.

Although smoking by adults in Turkey is a widely practiced, socially accepted habit, social influences on tobacco uptake by Turkish youth have been studied little. This paper reports findings from interviews (42 10th graders plus 10 other students and 24 adults) and three focus groups in a study with high school students in Dursunbey, Turkey. Interviewees reported that youth smoking is not culturally acceptable, but that contradictory messages and pressures abound. A context in which smoking is embedded in men's and women's social environments influences many youth to become smokers. Smoking is expected of men by the time they enter military service or are economically independent. Smoking by women, especially professionals, is increasingly common. Although virtually all adults disapprove of youth's smoking as age-inappropriate behavior, ubiquitous counter-examples of adult smoking in homes, schools, coffee houses and media dilute tobacco controls. Few youth or adults expressed concern about the relationship of tobacco to health. Sanctions in family and school environments are little enforced. Students' smoking-related attitudes and behaviors appear modeled more after behavior of their teachers than their less-educated parents, and smoking is common by teachers at school. Reduction of smoking by Turkish youth calls for comprehensive, sustained programs to de-normalize tobacco use in family, school and other settings, with special attention to smoking uptake by young women.

Adolescent↗
PubMed2004

The EAG tool: a decision support system for selection of abdominal aorta aneurysm endografts.

This article describes a decision support system (the EAG tool = Effective AAA Graftmanship) that assists the vascular surgeon in deciding whether a patient is fit for an endograft procedure and that assists the vascular surgeon in selecting the proper graft and in planning the endograft procedure. The EAG tool is the first step in the development of a learning environment for AAA procedures. As such the EAG tool is part of the VREST development project aiming to create a complete set of Virtual Reality Educational Surgical Tools. The EAG tool has been validated by using the expert knowledge of five experienced AAA physicians: three vascular surgeons and two interventional radiologists. In over 3,000 assessments, the EAG tool showed a false-positive rate of 0.2%, or in other words: in only 1 out of 500 cases the EAG tool indicated the possible use of an endograft, whereas the combined group of experts believed that it was not possibe. The EAG tool proved to be more prudent than the group of experts in having a false-negative rate of 3.7%. The EAG tool thus proved to be useful in daily clinical practice. Further developments are ongoing to use the EAG tool in a learning environment, specifically for unexperienced physicians.

Aortic Aneurysm, Abdominal↗
PubMed2005

Sparse, environmentally selective expression of Arc RNA in the upper blade of the rodent fascia dentata by brief spatial experience.

After a spatial behavioral experience, hippocampal CA1 pyramidal cells express the activity-regulated, immediate early gene Arc in an environment-specific manner, and in similar proportions ( 40%) to cells exhibiting electrophysiologically recorded place fields under similar conditions. Theoretical accounts of the function of the fascia dentata suggest that it plays a role in pattern separation during encoding. The hypothesis that the dentate gyrus (DG) uses a sparse, and thus more orthogonal, coding scheme has been supported by the observation that, while granule cells do exhibit place fields, most are silent in a given environment. To quantify the degree of sparsity of DG coding and its corresponding ability to generate distinct environmental representations, behaviorally induced Arc expression was assessed using in situ hybridization coupled with confocal microscopy. The proportion of Arc(+) cells in the "upper blade" of the fascia dentata (i.e., the portion that abuts CA1) increased in an environment-specific fashion, approximately 4-fold above cage-control activity, after behavioral exploration. Surprisingly, cells in the lower blade of the fascia dentata, which are capable of expressing Arc following electrical stimulation, exhibited virtually no behaviorally-induced Arc expression. This difference was confirmed using "line scan" analyses, which also revealed no patterns or gradients of activity along the upper blade of the DG. The expression of Arc in the upper blade was quantitatively similar after exploring familiar or novel environments. When animals explored two different environments, separated by 20 min, a new group of cells responded to the second environment, whereas two separated experiences in the same environment did not activate a new set of granular cells. Thus, granule cells generate distinct codes for different environments. These findings suggest differential contribution of upper and lower blade neurons to plastic networks and confirm the hypothesis that the DG uses sparse coding that may facilitate orthogonalization of information.

Animals↗
PubMed2005

An online interactive simulation system for medical imaging education.

This report presents a recently developed web-based medical imaging simulation system for teaching students or other trainees who plan to work in the medical imaging field. The increased importance of computer and information technology widely applied to different imaging techniques in clinics and medical research necessitates a comprehensive medical imaging education program. A complete tutorial of simulations introducing popular imaging modalities, such as X-ray, MRI, CT, ultrasound and PET, forms an essential component of such an education. Internet technologies provide a vehicle to carry medical imaging education online. There exist a number of internet-based medical imaging hyper-books or online documentations. However, there are few providing interactive computational simulations. We focus on delivering knowledge of the physical principles and engineering implementation of medical imaging techniques through an interactive website environment. The online medical imaging simulation system presented in this report outlines basic principles underlying different imaging techniques and image processing algorithms and offers trainees an interactive virtual laboratory. For education purposes, this system aims to provide general understanding of each imaging modality with comprehensive explanations, ample illustrations and copious references as its thrust, rather than complex physics or detailed math. This report specifically describes the development of the tutorial for commonly used medical imaging modalities. An internet-accessible interface is used to simulate various imaging algorithms with user-adjustable parameters. The tutorial is under the MATLAB Web Server environment. Macromedia Director MX is used to develop interactive animations integrating theory with graphic-oriented simulations. HTML and JavaScript are used to enable a user to explore these modules online in a web browser. Numerous multiple choice questions, links and references for advanced study are provided in the tutorial for trainees to verify their understanding of each unit. It is expected that this tutorial will enhance medical imaging education, help trainees in subsequent analysis of image data, and form the basis for the development of more advanced technologies in the future.

Computer Simulation↗
PubMed2001

Effect of DL-alpha-lipoic acid on glutathione metabolic enzymes in aged rats.

Ageing is characterized by a failure to maintain homeostasis under conditions of physiological stress, with an increasing susceptibility to disease and death. The accumulation of errors committed by faulty biochemical reactions over a vast period generates the cumulative effect observed during ageing. The most notable among the effects of ageing are the age-related disorders where free radicals are the major cause. When the level of free radicals increases because of diet, lifestyle, environment or other influences, it results in subsequent reduction of antioxidants. Reduced glutathione is one of the most fascinating molecules virtually present in all animal cells in often quite higher concentrations. An essential mechanism that accounts for most of the metabolic and cell regulatory properties of glutathione is the thiol disulfide exchange equilibria. We evaluated the age-associated alterations in glutathione dependent enzymes, glutathione and hydroxyl radicals in young and aged rats with respect to lipoate supplementation. In aged rats, activities of glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glucose-6-phosphate dehydrogenase and the level of glutathione were low, whereas the level of hydroxyl radical was higher than in the young ones. Administration of DL-alpha-lipoic acid, a thiol antioxidant intraperitoneally to the aged rats, led to a time-dependent reduction in hydroxyl radicals and elevation in the activities/level of glutathione systems. Hence it can be suggested that lipoate, a dithiol prevents the oxidation of reduced glutathione and protects its related enzymes from peroxidative damage.

Aging↗