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PubMed2005

Recent gravity-assist trajectories for interplanetary and solar exploration.

This paper describes how lunar and planetary gravity assists have been used to design trajectories that have enabled challenging missions, currently flying or in development, at the Applied Physics Laboratory (APL) of Johns Hopkins University, to explore the Sun, and the planets closest to and farthest from it. This is a continuation of a paper presented at the first New Trends in Astrodynamics and Applications conference, January 2003. That paper concentrated on the Third International Sun-Earth Explorer (ISEE-3) halo orbit mission, later known as the International Cometary Explorer, or ICE, and the Near Earth Asteroid Rendezvous (NEAR) mission of APL, and the ground-breaking orbits that those spacecraft used to accomplish their ambitious goals. This paper gives much more information about current APL missions, MESSENGER, STEREO, and New Horizons, which were only briefly described in the previous paper.

Journal Article↗

PubMed1987

Comparative study of bacteriological contamination between primary and secondary exploration of missile head wounds.

Aerobic and anaerobic bacterial contamination of scalp wounds, indriven bone fragments, and brain tracks were studied in two groups (A and B) of nonrandomized patients with missile head wounds in a 20-month study of patients from the front lines of the Iran-Iraq war. In the 53 Group B patients, the primary debridements, most of which had been performed within 24 hours after injury, were deemed insufficient and a secondary definitive exploration was performed. Group A patients (62) had primary definitive explorations at Nemazee Hospital after a mean of 66.5 hours since injury. All of the patients had been started on dexamethasone and a combination of either ampicillin and chloramphenicol or crystalline penicillin G and chloramphenicol after field evacuation. The contamination rate of scalp wounds, bone fragments and brain tracks was slightly higher in Group A (38.4%, 22.2%, and 29.6% respectively, for Group A and 31.9%, 19.5%, and 27% for Group B, respectively). Staphylococcus albus among the gram-positive and Acinetobacter among gram-negative bacteria were the most common infecting organisms. Fifty per cent of the bacteria cultured from the brain tracks of Group A and 30.8% of those cultured from Group B patients were gram-negative. A total of 125 patients in four groups was included in our overall study of victims of missile wounds that violated the dura mater. Four patients developed meningitis at Nemazee Hospital (3 postoperatively and 1 after facial penetration). Two patients in Group B were admitted with meningitis (1 with an accompanying abscess), 1 of them 20 days and the other 60 days after exploration at two different centers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Preliminary experiences with brachial plexus exploration in children: birth injury and vehicular trauma.

The application of microsurgical techniques to the peripheral nervous system has made possible the reconstruction of the brachial plexus after vehicular and penetrating injuries. We now report our preliminary experiences utilizing these same techniques in the microsurgical management of brachial plexus birth injury. In contrast to other authors and in distinction from our own experiences with vehicular trauma in children, we did not find lesions requiring reconstruction by grafting or neurotization in any of seven plexus explorations for birth injury. The history of the surgical management of brachial plexus birth injury is reviewed, and the rationale for exploration is developed in the context of the natural history of the condition. Differences between our experiences and the existing literature are analyzed, with particular regard for timing of operation and technique of intraoperative assessment of nerve injury. All children with birth injuries of the brachial plexus require careful, repeated neurological evaluation during the first few months of life. Although the great majority make a rapid and satisfactory spontaneous recovery, the minority who do not recover are destined to suffer significant, life-long disability. Microsurgical brachial plexus exploration may benefit this select group of patients.

Accidents, Traffic↗

PubMed2004

Endoscopic exploration of the brachial plexus: technique and topographic anatomy--a study in fresh human cadavers.

OBJECTIVE: The indications for and timing of brachial plexus exploration in closed injuries are controversial. The time-consuming surgery proves its worth in some cases, whereas spontaneous regeneration might have been possible in others. The differentiation is difficult, because no investigational method reveals the exact morphological correlates of the nerve lesions. Minimally invasive, direct observation of the structures is a possible solution. Here we describe our surgical technique and the anatomic features of the normal brachial plexus appreciated with the endoscope. METHODS: Twenty-one brachial plexus in 11 fresh cadavers were investigated. Endoscopic exploration was performed at the supraclavicular and infraclavicular levels. The method involves insertion of an optic shaft-integrated retractor through a stab wound; retraction of landmark muscles produces a working space, into which other instruments are introduced for dissection. After completion of endoscopic surgery, open dissection was performed to verify the endoscopically identified structures and to assess iatrogenic injuries. RESULTS: The omohyoid muscle is a reliable landmark in the supraclavicular region, beneath which the suprascapular nerve can be observed. Following the suprascapular nerve proximally leads to the plexus trunks. Infraclavicular exploration first reveals the axillary artery. The plexus and its nerves are traced around this artery. The anatomic features were constant in all cases, with variations in fat accumulation depending on the corporeal constitution. We detected iatrogenic injuries to the medial circumflex humeral vessels in two cases. No nerve injuries were observed. CONCLUSION: The endoscopic technique combined with intraoperative nerve stimulation studies might provide important information on the type of morphological damage in closed brachial plexus injuries and thus might become an important tool for determination of the surgical treatment strategy. Clinical work is under way.

Aged↗

PubMed1997

Hippocampal histamine receptors and conflictive exploration in the rat: studies using the elevated asymmetric plus-maze.

The possible role of histamine receptors in the hippocampal formation on the exploratory motivation and emotionality of the rat was studied. An elevated asymmetric plus-maze composed of 4 different arms (no walls, single high wall, high and low walls and two high walls) arranged at 90 degrees angles was used. The exploration score, considered to be an index of exploratory motivation, and the permanency score, considered to be an index of emotionality (anxiety), were determined. Histamine was administered locally into the ventral hippocampus at three different doses (9, 45 and 90 nmol). Another group of rats was also microinjected with 45 nmol of pyrilamine (a histamine H1 receptor antagonist) or ranitidine (a histamine H2 receptor antagonist) in addition to 9 nmol of histamine in order to identify the possible type of histamine receptor involved. Histamine administration significantly inhibited the exploration score and increased the permanency score at the doses of 9 and 45 nmol in two of four arms. These effects were completely blocked by the administration of either histamine receptor antagonist. The present results suggest that in the hippocampal formation histamine inhibits exploratory motivation and decreases emotionality by activating both types of histamine receptors. Also, the elevated asymmetric plus-maze appears to be a suitable technique to quantify exploration and possibly "anxiety".

Animals↗

PubMed2005

PET and SPECT exploration of central monoaminergic transporters for the development of new drugs and treatments in brain disorders.

Membrane and vesicular monoaminergic transporters, responsible for the homeostasis of neurotransmitter pools at nerve endings, are very involved in the physiology and diseases of central nervous system. Recent progresses of cerebral molecular imaging using SPECT and PET methods allow the extend of in vivo exploration of these transporters. For this aim, an increasing number of radiopharmaceuticals labelled with [123I], [99mTc], [11C] or [18F] have been developed such as cocaine derivatives for the DAT, compounds from the diphenyl sulfide family for the SERT, and dihydrotetrabenazine derivatives for the VMAT2. These functional imaging methods can be very useful in several neurological and psychiatric disorders which involve the monoaminergic neurotransmission systems such as Parkinson's disease, ADHD, depression and autism. For example, the DAT is a specific index of the density of dopaminergic endings which progressively degenerate in Parkinson's disease. In vivo exploration of this transporter can therefore be a relevant way (i) to realize an early detection of the loss of dopaminergic neurons, (ii) to assess the progression of the disease, (iii) to validate and improve the efficacy of new therapeutic strategies such as neuroprotection and neuroreparation. In all, the extend of in vivo exploration of monoamine transporters will allow great progress for (1) knowledge of physiopathological mechanisms of brain disorders, (2) early diagnosis of cerebral dysfunctions, allowing early use of new therapies, (3) selection of homogenous classes of subjects for therapeutic assays, (4) objectiveness of drug-molecular target interaction, (5) follow-up of disease evolution and treatment.

Attention Deficit Disorder with Hyperactivity↗

PubMed1989

Effects of information conflict and complexity in visual figures on voluntary visual exploration, using structural information theory.

This study was designed to examine the effects of information conflict and complexity on voluntary visual exploration quantitatively. 31 adults viewed each of 16 slides of geometrical figures and places for as long as they wished. The stimuli had two values of information conflict and complexity which had been calculated by means of structural information theory. Free looking times indicated that only when information conflict was low, voluntary visual exploration was positively correlated with complexity. Furthermore, voluntary visual exploration correlated positively with information conflict when complexity was low.

Adult↗

PubMed1999

Influences of adult attachment in exploration.

Research into the relationship between attachment quality in both children and adults suggests links with patterns of exploration; however, exploration has been operationalized differently in studies of adults and children. This study examined adults' patterns of exploration operationalized in terms of novelty seeking, curiosity, and impulsivity, as in studies of children. Analysis indicated avoidant adults reported significantly lower curiosity than did securely attached adults, while preoccupied subjects showed no differences from either secure or avoidant groups. As in studies of children, groups did not differ on measures of novelty seeking or impulsivity.

Adult↗

PubMed2001

A preliminary study of proposed levels of relatedness in identity exploration among female late adolescents in Japan.

This study examined features of identity exploration among late adolescent Japanese girls from the viewpoint of relatedness. The expanded Ego Identity Interview was administered to 33 female university students. Five levels of relatedness were formulated in a sequence from exploration without relatedness to exploration with disagreements between one's own and others' perspectives. The results support the current view of researchers emphasizing relational aspects of identity and provide detailed features of the identity formation process from the viewpoint of relatedness among late adolescent girls in Japan.

Adolescent↗

PubMed1992

Stages of manual exploration in haptic object identification.

In a yes/no identification task using touch alone, subjects indicated whether an object belonged to a named category. Previously, we found that subjects explored in two stages--first grasping and lifting the object, then executing further exploratory procedures (Lederman & Klatzky, 1990b). We proposed that Stage 1 (grasp/lift) was sufficient to extract coarse information about multiple object properties, whereas Stage 2 was directed toward precise information about particularly diagnostic properties. In the current study, subjects were initially constrained to grasping and lifting, after which they could explore further. Accuracy was above chance after Stage 1, confirming our assumption that the grasp/lift combination was broadly useful. Stage 2 increased accuracy and confidence. It primarily elicited exploratory procedures associated with object geometry, but exploration was also influenced by diagnostic object properties.

Adult↗

PubMed2006

Using data mining to explore complex clinical decisions: A study of hospitalization after a suicide attempt.

BACKGROUND: Medical education is moving toward developing guidelines using the evidence-based approach; however, controlled data are missing for answering complex treatment decisions such as those made during suicide attempts. A new set of statistical techniques called data mining (or machine learning) is being used by different industries to explore complex databases and can be used to explore large clinical databases. METHOD: The study goal was to reanalyze, using data mining techniques, a published study of which variables predicted psychiatrists' decisions to hospitalize in 509 suicide attempters over the age of 18 years who were assessed in the emergency department. Patients were recruited for the study between 1996 and 1998. Traditional multivariate statistics were compared with data mining techniques to determine variables predicting hospitalization. RESULTS: Five analyses done by psychiatric researchers using traditional statistical techniques classified 72% to 88% of patients correctly. The model developed by researchers with no psychiatric knowledge and employing data mining techniques used 5 variables (drug consumption during the attempt, relief that the attempt was not effective, lack of family support, being a housewife, and family history of suicide attempts) and classified 99% of patients correctly (99% sensitivity and 100% specificity). CONCLUSIONS: This reanalysis of a published study fundamentally tries to make the point that these new multivariate techniques, called data mining, can be used to study large clinical databases in psychiatry. Data mining techniques may be used to explore important treatment questions and outcomes in large clinical databases and to help develop guidelines for problems where controlled data are difficult to obtain. New opportunities for good clinical research may be developed by using data mining analyses.

Adult↗

PubMed1995

Exploring nurses' storied accounts of practice.

The learning opportunities presented in nurses' storied accounts of practice are explored. This exploration is achieved through analysis and discussion of three nurse's stories documented in the literature, and uses Benner's (1991) narratives of learning theme as the conceptual framework. The narrative of learning sub themes: being open to experience, liberation, and disillusionment are examined. This examination suggests nurses stories can be used to: discover nursing knowledge, develop shared understandings of what it is to be a nurse, examine nursing's culture and ethics, document interactions for research, teaching and learning, and identify and preserve the practice of nursing. Whereas edited stories from the literature only begin to demonstrate the possibilities for learning that stories offer, through them alternative ways of learning about nursing, exploring nursing practice and developing nursing knowledge are presented.

Humans↗

PubMed1997

The effect of naloxone on object exploration, object recognition and other types of spontaneous behavior.

Object exploration was examined in naloxone injected (1 mg/kg or 4 mg/kg) and saline control rats. Naloxone rats explored an object for a shorter time than did controls, thus indicating a lower investigatory motivation. This effect was dose dependent. Higher drug dose (4 mg/kg) decreased the number of contacts with an object. Both doses increased the mean duration of contacts with an object. The naloxone groups showed intact recognition of a familiar object paired with a new one in two sessions--4 h and 24 h after the injections. The higher drug dose depressed the locomotor activity and wall leaning. Grooming was not influenced by naloxone. The normal daily fluctuations in the level of grooming and locomotion were distorted following the injection of the higher dose of naloxone. The lower dose (1 mg/kg) did not affect the rats' performance in some tests. The results could be viewed as a naloxone-related depression of the behavior containing motor elements like locomotion, wall leaning and object approaching. The prolonged contact time with an object could be the result of a lowered flexibility of movement. However, the decrease of rewarding value of exploration could not be ruled out. Possibly, naloxone exerts several different interacting behavioral effects.

Animals↗

PubMed1999

Exploring the concepts of intended, planned, and wanted pregnancy.

BACKGROUND: A variety of terms have been used to define the intention status of pregnancies. The purpose of this study was to explore how women relate to these terms and how they define the intention status of their pregnancies. Improved understanding of how women use these terms may enhance communication between physicians, patients, and families. METHODS: This qualitative study used in-depth semistructured interviews to explore how women defined the intention status of current, past, and hypothetical pregnancies. Eighteen women who were seeking prenatal care, elective abortion, or pregnancy testing were interviewed. Most of the subjects were interviewed in the first trimester of a current pregnancy. Four researchers independently reviewed the interview transcripts and summarized the points made by each subject. RESULTS: Three major themes emerged from the interviews: (1) definitions of terms related to pregnancy varied substantially among women and seemed to be highly correlated to social and cultural influences; (2) the concepts of wanted and unwanted pregnancy were qualitatively distinct from the concepts of planned and unplanned pregnancies and seemed to be more relevant to the decision to continue or abort the pregnancy; and (3) attitudes of the male partners toward the pregnancies were very influential in how women defined their pregnancies. CONCLUSIONS: Physicians should explore the attitudes and circumstances of pregnant women, rather than focusing on whether the pregnancy was planned. Support from the significant other and the woman's underlying values about parenthood seem to be of particular importance. Our results also suggest that further studies are needed to determine the best method for measuring the intention status of pregnancy for research and policy.

Adolescent↗

PubMedDate not supplied

Results of retrograde transhepatic biliary drainage after a common bile duct exploration for choledocholithiasis.

BACKGROUND/AIMS: The purpose of this study is to assess the benefits of retrograde transhepatic biliary drainage (RTBD) and a primary closure after a common bile duct (CBD) exploration for patients with choledocholithiasis. METHODOLOGY: We analyzed 143 patients with choledocholithiasis who had been managed by RTBD after undergoing a CBD exploration retrospectively over a 12-year period. The main outcome criteria were frequency of occurrence of post-operative complications which needed a relaparotomy and the clinical long-term results. In addition, the radiographic diameter changes of the CBD at the site of the primary closure and liver function tests after RTBD were also evaluated. RESULTS: The frequency of bile peritonitis in the patients undergoing the RTBD procedure was only 0.7% (1 out of 143 cases). Cholangiography via the RTBD tube revealed no severe stenosis at the site of primary closure. Liver function returned to normal on day 3 after RTBD (p<0.05). Recurrence of common bile duct stones developed in 2 patients in this series during the follow-up (1-12 years). CONCLUSIONS: RTBD and a primary closure of the CBD after CBD exploration appears to be a clinically safe and effective method for such patients with choledocholithiasis who had undergone a complete stone removal intra-operatively.

Adult↗

PubMed1999

Intelligent visualization and exploration of time-oriented clinical data.

Physicians and other care providers often need to quickly browse and interpret large numbers of time-oriented clinical data. Reducing the information overload involving such tasks is a major goal for medical information systems. We describe a conceptual architecture and software implementation specific to the task of interpretation, summarization, visualization, explanation, and interactive exploration of time-oriented clinical data and the multiple levels of meaningful concepts that can be derived from these data. We build on our work on abstraction of time-oriented clinical data using a knowledge base, acquired from expert physicians, of temporal properties of the data. The core module of the new framework is called KNAVE (Knowledge-based Navigation of Abstractions for Visualization and Explanation). Health care providers can manipulate the display though several visualization and exploration operators. These operators have semantics that are domain independent but that are customized automatically for the application by access to the domain-specific knowledge base. The display, which reflects data and derived interpretations in the patient's database, changes when the user explores key relations (e.g., the dependency hierarchy) in the knowledge base of the relevant clinical domain. Preliminary assessment of the initial prototype with several clinical users has been encouraging. The KNAVE methodology has broad ramifications for reducing the load that large numbers of time-oriented clinical data put on care providers.

Artificial Intelligence↗

PubMed2000

Pancreatic carcinoma deemed unresectable at exploration may be resected for cure: an institutional experience.

Only a minority of patients with a diagnosis of pancreatic adenocarcinoma (PA) have disease amenable to curative resection. Between April 1987 and March 1999, 40 patients with pancreatic adenocarcinoma deemed unresectable at exploration at other institutions were considered for neoadjuvant treatments and then re-evaluated for possible re-exploration. We retrospectively compared the clinical outcomes, including overall survival (OS), among three groups: Group A, 22 previously unresectable patients who were subsequently successfully resected, 20 after induction therapy; Group B, 31 patients who received preoperative chemoradiotherapy before their only operation; and Group C, 33 patients who were primarily resected, 27 of whom were then treated with adjuvant therapy. Of those resectable from Group A, 5 required portal venorrhaphy and 3 had hepatic artery reconstruction. Eighteen of the 40 patients were unresectable because of progression of disease with a mean OS of 8 months; 12 were assessed at second laparotomy; 6 were excluded from second operation on the basis of preoperative imaging studies. Kaplan-Meier curves showed no differences in OS among the three groups: OS in Group A was 34 months; Group B, 21; and Group C, 13 (P = 0.15). Margin status was comparable in all three groups (P = 0.52). As expected, nodal positivity was greatest in Group C (P = 0.001). There were no operative mortalities in Group A, and the morbidity rate was comparable with that of Groups B and C. Upon re-evaluation, many tumors (54%) previously deemed "unresectable" were surgically extirpated for cure with a median survival comparable with that of patients who did not undergo previous exploration.

Adenocarcinoma↗

PubMed1991

Human exploration of Mars.

The human exploration of Mars has the potential to return a rich harvest of scientific information about that planet, its possible past biological history and the prospects for future habitation by Earthly life. The realization of that potential will require new approaches and new technologies--a whole new paradigm in space exploration. Picture yourself exploring the surface of Mars, where your task involves conducting a detailed investigation of features larger than the United States in order to uncover a record of planetary history spanning over four billion years.

Atmosphere↗