bluuebunny/crossref_metadata_2025 huggingface dataset:
Demographic Impact of Epilepsy in Africa: Results of a 10‐year Cohort Study in a Rural Area of Cameroon
Authors: Kamgno Joseph , Pion Sébastien D. S. , Boussinesq Michel
Published: June 2003

Summary:  Purpose: To evaluate the demographic impact of epilepsy a rural area of Africa.

Methods: A cohort study was conducted between 1991 and 2001 in the Mbam Valley (Cameroon) on two groups of subjects (one of persons with epilepsy, and the other of control individuals matched for sex, age, and village of residence). At the end of the follow‐up, information on mortality, marital status, and numbers of offspring was obtained from 128 pairs of subjects.

Results: Thirty‐seven (28.9%) persons with epilepsy and six (4.7%) controls died between 1991 and 2001. The relative risk of dying during the follow‐up among the group of people with epilepsy, compared with the controls, was 6.2 (95% CI, 2.7–14.1). The most frequent causes of death in the persons with epilepsy were status epilepticus, sudden unexpected death in epilepsy (SUDEP), and drowning. Of the 90 pairs, of which both members were still alive in 2001, 15 (16.7%) persons with epilepsy were married as compared with 53 (58.9%) controls. The mean number of children was 0.9 in the subjects with epilepsy, and 1.7 in the controls (p < 0.0001).

Conclusions: Health personnel should be trained and sensitized about the devastating effect of this neglected disease in developing countries. In those areas where onchocerciasis control programs are organized by using the community‐directed‐treatment approach, the possibility that the ivermectin distributors could also be responsible for distributing antiepileptic drugs should be considered.
A New Chrna4 Mutation with Low Penetrance in Nocturnal Frontal Lobe Epilepsy
Authors: Leniger Tobias , Kananura Colette , Hufnagel Andreas , Bertrand Sonia , Bertrand Daniel , Steinlein Ortrud K.
Published: June 2003

Summary:  Purpose: To identify and characterize the mutation(s) causing nocturnal frontal lobe epilepsy in a German extended family.

Methods: Neuronal nicotinic acetylcholine receptor (nAChR) subunit genes were screened by direct sequencing. Once a CHRNA4 mutation was identified, its biophysical and pharmacologic properties were characterized by expression experiments in Xenopus oocytes.

Results: We report a new CHRNA4 mutation, causing a α4‐T265I amino acid exchange at the extracellular end of the second transmembrane domain (TM). Functional studies of α4‐T265I revealed an increased ACh sensitivity of the mutated receptors. α4‐T265I is associated with an unusual low penetrance of the epilepsy phenotype. Sequencing of the TM1‐TM3 parts of the 1 known nAChR subunits did not support a two‐locus model involving a second nAChR sequence variation.

Conclusions: nAChR mutations found in familial epilepsy are not always associated with an autosomal dominant mode of inheritance. α4‐T265I is the first nAChR allele showing a markedly reduced penetrance consistent with a major gene effect. The low penetrance of the mutation is probably caused by unknown genetic or environmental factors or both.
Long‐term Pregabalin Treatment Protects Basal Cortices and Delays the Occurrence of Spontaneous Seizures in the Lithium‐Pilocarpine Model in the Rat
Authors: André Véronique , Rigoulot Marie‐Aude , Koning Estelle , Ferrandon Arielle , Nehlig Astrid
Published: June 2003

Summary:  Purpose: To determine whether a pharmacologic treatment could delay or prevent the epileptogenesis induced by status epilepticus (SE) through the protection of some brain areas, we studied the effects of the long‐term exposure to pregabalin (PGB) on neuronal damage and epileptogenesis induced by lithium‐pilocarpine SE.

Methods: SE was induced in adult and 21‐day‐old (P21) rats. At 20 min after pilocarpine, rats received 50 mg/kg PGB (pilo‐preg) or saline (pilo‐saline). PGB treatment was given daily at the dose of 50 mg/kg for 7 days after SE and at 10 mg/kg from day 8 until killing. Neuronal damage was assessed in hippocampus and piriform and entorhinal cortices in brain sections stained with thionine and obtained from adult and P21 animals killed 6 days after SE. The number of glial fibrillary acidic protein (GFAP)‐reactive astrocytes was tested by immunohistochemistry in sections adjacent to those used for cell counting. The latency to spontaneous seizures was controlled by visual observation and EEG recording.

Results: PGB induced neuroprotection in layer II of piriform cortex and layers III–IV of ventral entorhinal cortex of adult rats, whereas no hippocampal region was protected. In P21 rats, damage was limited to the hilus and similar in pilo‐preg and pilo‐saline animals. The number of GFAP‐positive astrocytes was higher in pilocarpine‐ than in saline‐treated rats. It was decreased in pilo‐preg compared with pilo‐saline rats in layer II of the piriform cortex. Adult pilo‐preg rats became epileptic after a longer latency (39 days) than did pilo‐saline rats (22 days).

Conclusions: These data underline the antiepileptogenic consequences of long‐term PGB treatment, possibly mediated by the protection of piriform and entorhinal cortices in the lithium‐pilocarpine model of epilepsy.
Serum Carbamazepine Concentrations in Elderly Patients: A Case‐matched Pharmacokinetic Evaluation Based on Therapeutic Drug Monitoring Data
Authors: Battino Dina , Croci Danilo , Rossini Alessandro , Messina Sara , Mamoli Daniela , Perucca Emilio
Published: June 2003

Summary:  Purpose: To assess the influence of aging on the steady‐state pharmacokinetics of carbamazepine (CBZ) in a large population of patients evaluated in a therapeutic drug monitoring (TDM) setting.

Methods: The database of a large TDM service was used to identify retrospectively steady‐state serum CBZ concentrations in 157 elderly patients with epilepsy (65 years and older) treated with CBZ alone or in combination with phenobarbital (PB). CBZ apparent oral clearance (CL/F) values were calculated and compared with those determined in an equal number of controls aged 20 to 50 years, and matched for gender, body weight, and comedication.

Results: Compared with corresponding controls, mean CBZ CL/F values were 23% and 24% lower, respectively, in the groups of elderly patients receiving monotherapy (57.1 ± 20.6 vs. 74.6 ± 28.3 ml/h/kg; p < 0.0001) and PB comedication (74.7 ± 25.5 vs. 98.7 ± 34.9 ml/h/kg; p < 0.01). Within each age group, patients comedicated with PB showed significantly higher CBZ CL/F values than those on monotherapy. A negative correlation between CL/F and age was found both within the monotherapy and the PB comedicated groups. In addition, CL/F values showed a positive relation with the administered daily dosage, which persisted within subgroups homogeneous for age and comedication. The independent influence of age, CBZ dosage, and comedication on CBZ CL/F was confirmed by multiple regression analysis.

Conclusions: CBZ CL/F is decreased in an age‐dependent manner in elderly patients compared with younger subjects, presumably because a reduction in the rate of CYP3A4‐mediated drug metabolism. Elderly patients retain their sensitivity to dose‐dependent autoinduction and to heteroinduction by enzyme‐inducing AEDs, but their metabolic rates remain considerably below those observed in matched controls. As a result of this, patients in old age will require lower CBZ dosages to achieve serum concentrations comparable with those found in nonelderly adults.
Incidence and Short‐term Prognosis of Status Epilepticus in Adults in Bologna, Italy
Authors: Vignatelli Luca , Tonon Caterina , D'Alessandro Roberto ,   Bologna Group for the Study of Status Epilepticus
Published: June 2003

Summary:  Purpose: To determine the incidence and the 30‐day case fatality of status epilepticus (SE) in the adult resident population of the city of Bologna, Italy.

Methods: Over a 1‐year period (March 1, 1999 to February 29, 2000), all patients older than 20 years with SE were included. The case‐finding method was based on (a) a prospective surveillance of all public general hospitals in the city by neurologic units, and (b) a review of all discharge codes concerning epilepsy.

Results: The crude and standardized annual incidence rate of SE was 13.1 per 100,000 [95% confidence interval (CI), 9.5–17.5] and 10.7 (95% CI, 7.5–13.8). It was higher in the elderly (older than 60 years) than in young adults (26.2 vs. 5.2) and in women than in men (14.9 vs. 11.0). Acute symptomatic SE accounted for 48%, and a cerebrovascular pathology was the most frequently associated etiologic condition (41%). A history of seizures was reported in 39% of patients. The 30‐day case fatality was 39% (33% excluding postanoxic patients).

Conclusions: This study reports the first data on the epidemiology of SE in Italy. The incidence rate found in the population of Bologna is in the same range as that of the other European countries. The 30‐day case fatality is higher than all the other population studies (both European and American), despite the broadly similar clinical features of patients. Indirect evidence suggests that some inaccurate patient management could have negatively influenced the outcome of SE.
Topiramate and Lamotrigine Pharmacokinetics during Repetitive Monotherapy and Combination Therapy in Epilepsy Patients
Authors: Doose Dennis R. , Brodie Martin J. , Wilson Elaine A. , Chadwick David , Oxbury John , Berry David J. , Schwabe Stefan , Bialer Meir
Published: June 2003

Summary:  Purpose: To determine at steady state (in the same group of patients): (a) the pharmacokinetics (PK) of lamotrigine (LTG) with LTG monotherapy, (b) the PK of LTG concomitantly administered with topiramate (TPM) at three escalating TPM doses (100, 200, and 400 mg/day), (c) the PK of TPM at three escalating TPM doses while receiving fixed‐dose LTG therapy, and (d) the PK of TPM with TPM monotherapy.

Methods: This was an open‐label, sequential, single‐group, dose‐escalating PK study in which 13 patients with epilepsy not optimally controlled with LTG received stable‐dose LTG monotherapy for 2 weeks, followed by stable‐dose LTG therapy combined with escalating doses of TPM for ≤16 weeks, stable‐dose TPM therapy combined with tapered‐dose LTG therapy for 4 weeks, and stable‐dose TPM monotherapy for 2 weeks. Serial blood and urine samples were collected before and during TPM dosing, and safety data were collected throughout the study.

Results: The exposure, or area under the plasma LTG concentration–time curve within a dosing interval at steady state (AUCss), did not change in the presence of TPM, with mean AUCss values ranging at each TPM dose level between 66 and 81 mg×h/L with concomitant LTG/TPM therapy compared with 77 mg×h/L with LTG monotherapy. No significant change was found in the steady‐state peak (Cmax) and trough (Cmin) plasma levels of LTG in the presence and absence of TPM. The mean (±SD) oral clearance (CL/F) of TPM (400 mg/day) was 2.6 ± 1.1 L/h when given alone and 2.7 ± 0.7 L/h when given with LTG. The similarity of CL/F values also was reflected by the similar exposure (AUCss), Cmax, and Cmin values of TPM in the absence, and presence of LTG.

Conclusions: The results of this study show that no PK interaction between TPM and LTGwas observed at the doses used in this study.
Can Hand‐Carried Ultrasound Devices be Extended for Use by the Noncardiology Medical Community?
Authors: Duvall W. Lane , Croft Lori B. , Goldman Martin E.
Published: June 2003

Echocardiography (echo) is a powerful, noninvasive, inexpensive diagnostic imaging technique that provides important information in a variety of cardiovascular diseases. Echo provides rapid information regarding ventricular and valvular function in the clinical management of patients. Smaller, relatively inexpensive hand‐carried cardiac ultrasound (HCU) devices have become commercially available, which can be used for diagnostic cardiac imaging. Because of their relative ease of use, portability, and affordable cost, these new hand‐held systems have made point‐of‐care (bedside) echocardiography available to all medical personnel. The rate‐limiting step to the widespread use of this technology is the lack of personnel with echo training at the immediate contact point with patients. Although extensive training and experience are needed to acquire and interpret a complete echo, training medical personnel to perform and interpret a limited echo (defined as a brief, diagnosis focused exam) may fully exploit the potential of echo as a point‐of‐care diagnostic tool and may be accomplished in a short period of time. Presently there are guidelines for independent competency in echocardiography and HCU echo established by several professional organizations and as a result of these rigorous guidelines, other noncardiology medical professionals who could practically derive the greatest benefit are discouraged and virtually precluded from utilizing echo during the initial encounter with the patient. However, there is now a growing body of literature in a diverse group of noncardiology medical personnel that demonstrates that it is possible to quickly and effectively train them to perform and interpret limited echocardiograms. Medical students, medical residents, cardiology fellows with limited experience, emergency department physicians, and surgical intensive care unit staff have all been evaluated after only brief, focused training periods, and investigators found that HCU echo provided important new information, changed therapeutic management, and was vastly superior to the physical exam alone with an acceptable overall level of accuracy. The contribution of echocardiography to the field of cardiovascular disease since its invention has been significant and the newer compact, portable, ultrasound systems have the potential to revolutionize the utilization and availability of echocardiography. To maximize integration of echo into medical practice, physicians and physician extenders could be trained to perform and interpret limited echo to complement their clinical examination and improve their diagnostic skills. The challenge is to provide practical training programs to assure competency in performing point of care echocardiograms. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
The Hand‐Carried Echocardiographic Device as an Aid to the Physical Examination
Authors: DeCara Jeanne M. , Lang Roberto M. , Spencer Kirk T.
Published: June 2003

Physical examination skills have been declining over the past several decades while technology has made diagnostic testing increasingly sophisticated. For patients with cardiovascular disease, the best approach to bedside diagnosis would be one that combines both physical examination and ready access to technology at the time of the patient encounter. Most cardiac testing is not performed at the bedside due to equipment size and time limitations for these tests. Small hand‐carried echocardiographic devices are now available for rapid bedside examination. These devices compare well to full‐featured systems when used in cardiology outpatient settings and in hospitalized patients who are not critically ill. Compared with physical examination by board certified cardiologists, these devices decrease diagnostic error. Early use of hand‐carried echocardiographic devices after physical examination has been demonstrated to impact patient triage and treatment as well as uncover otherwise undetected cardiac disease. The degree of training required for responsible use of these devices is as yet unclear. However, organized training sessions have resulted in modest agreement with standard echocardiography and point‐of‐care echocardiography performed by expert echocardiographers. It is conceivable that the hand‐carried echocardiographic devices will be used in medical school curriculum to enhance medical student education in the future. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Accuracy of Hand‐Carried Ultrasound
Authors: Liang David , Schnittger Ingela
Published: June 2003

Hand‐carried ultrasound introduces a new group of devices, operators and usage patterns to echocardiography. This may have significant impact on the accuracy of the findings obtained with hand‐carried ultrasound. Although reasonable agreement can be obtained with standard echocardiography in certain circumstances, limitations in imaging modes, device image quality, operator experience, and study completeness may significantly limit the diagnostic accuracy of hand carried ultrasound. Despite this, hand‐carried ultrasound has the potential to improve significantly upon the data obtained by physical examination. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Normal Lymph Nodes Mimicking a Mediastinal Mass During Transesophageal Echocardiography
Authors: Nekkanti Rajasekhar , Nanda Navin C. , Ahmed Sujood , Sanders Colleen
Published: June 2003

We report a transesophageal echocardiographic (TEE) study in an adult patient with ischemic stroke, in whom a nodular mass lesion consistent with tumor or mediastinal lymphadenopathy appeared to be interposed between the esophageal probe and the proximal descending aorta/aortic arch. Computed tomography (CT) scan of the chest revealed no pathologic lesions, only the presence of normal mediastinal lymph nodes and a rightward displaced esophagus. This unusual, but normal rightward position of the esophagus appears to have facilitated the visualization of these normal mediastinal lymph nodes on TEE. CT scan of the chest helped clarify the benign nature of these lymph nodes, which mimicked a mediastinal mass on TEE. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Undefined Hypercoaguable State Associated With Massive Right Ventricular Thrombus and Embolism in a Previously Healthy 17‐Year‐Old Male
Authors: Maraj Suraj , Bajpai Enakshi , Crespo Guillermo , Doshi Kokila , Langan Nicholas , Jacobs Larry E. , Kotler Morris N.
Published: June 2003

A right ventricular thrombus (RVT) is an unusual finding on echocardiography. We describe a healthy young male patient who developed RVT with subsequent pulmonary embolism (PE), the etiology of which remains uncertain. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Cyclic Variation of Myocardial Integrated Backscatter and Myocardial Wall Thickness During Percutaneous Coronary Angioplasty
Authors: Tekten Tarkan , Onbasili Alper O. , Ceyhan Ceyhun , Discigil Berent
Published: June 2003

Cyclic variation of myocardial integrated backscatter (CVIBS) and change in myocardial wall thickness (WT%) were evaluated during percutaneous transluminal coronary angioplasty (PTCA). Fourteen patients who underwent PTCA of the proximal left anterior descending (LAD) coronary artery were included in the study. PTCA was performed by inflating the balloon at the site of the LAD lesion for 1 minute. CVIBS was measured at three episodes during PTCA in the parasternal short‐axis view: before the inflation, at the end of 1‐minute inflation, and at the fifth‐minute after deflation of the balloon. Three regions of interest were used to evaluate the three‐vessel territories: mid‐anteroseptal area for LAD, mid‐posterolateral area for circumflex artery, and mid‐inferior area for right coronary artery. The WT% was calculated in each area. In the LAD territory, CVIBS measured at the end of 1‐minute inflation was lower than the values obtained before PTCA,

5.2 ± 1.0

decibel (dB) versus

3.7 ± 0.7 dB (P < 0.01)

. CVIBS magnitudes increased at the fifth‐minute after the deflation back up even to higher levels than pre‐PTCA values,

6.1 ± 1.0 dB

versus

5.2 ± 1.0 dB (P < 0.01)

. The WT% values decreased during balloon inflation but did not recover to the pre‐inflation values measured at fifth‐minute after deflation. In other sites, there was no change in either CVIBS or WT% values at any time studied. The observed increase in CVIBS may be an indicator of restoration of blood flow to ischemic myocardium. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Three‐Dimensional Transesophageal Echocardiographic Demonstration of Intraatrial Baffle Obstruction
Authors: Ahmed Sujood , Nekkanti Rajasekhar , Nanda Navin C. , Yousif Abdalla M.
Published: June 2003

We report an adult patient with transposition of the great arteries status post‐Mustard procedure in whom three‐dimensional transesophageal echocardiography demonstrated intraatrial baffle obstruction. The baffle could be visualized in both long‐axis and “en face” short‐axis views. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
A Method of Detecting and Quantifying Severity of Myocardial Perfusion Defects With Intravenous Ultrasound Contrast and Breath Holding During Stress Echocardiography
Authors: Porter Thomas R. , O'Leary Edward , Silver Mary , Oehlke Heidi , Xie Feng
Published: June 2003

Although breath holding is commonly used to improve and maintain image quality during stress echocardiography, its effects on the qualitative and quantitative analysis of myocardial contrast enhancement (MCE) following intravenously injected microbubbles is unknown. The purpose of this study was to determine how breath holding affects MCE following either an intravenous bolus or continuous infusion of perfluorocarbon containing microbubbles. In 48 patients, intravenous Optison was given at peak dobutamine stress to assess myocardial perfusion. The degree of myocardial opacification was assessed immediately following a breath hold in inspiration (BHini), at the end of a breath hold (BHterm), and following expiration and a subsequent second breath hold (BHreinsp). Pulmonary venous time velocity integrals were recorded during these different phases as well. Eleven patients had quantitative coronary angiography. Mean duration of the breath hold was

7 ± 1

seconds. Pulmonary venous return fell by

29%± 18%

at BHterm

(P < 0.001)

. There was complete disappearance of MCE at BHterm in 27 of 35 bolus injection patients at peak stress, and no return of MCE following flash destruction during breath holding in 11 of 13 patients receiving continuous infusions. BHreinsp resulted in a boluslike return of contrast, with a transient, bright MCE in 44 of 48 patients, and a time intensity plot that resembled a gamma variate function. Perfusion defects were visualized in 25 patients during BHini and 28 patients during BHreinsp. Coronary artery territory agreement between perfusion assessed during BHini and BHreinsp and quantitative coronary angiography was 76% and 81%, respectively. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Visual Quantitative Estimation: Semiquantitative Wall Motion Scoring and Determination of Ejection Fraction
Authors: Lavine Steven J. , Salacata Abraham
Published: June 2003

Ejection fraction (EF) is the most commonly used parameter of left ventricular (LV) systolic function and can be assessed by echocardiography. Quantitative echocardiography is time consuming and is as accurate as visual estimation, which has significant variability. We hypothesized that each echocardiographer has developed a mental set of guidelines that relate to how much individual segment shortening constitutes normal function or hypokinesis of varying extents. We determined the accuracy of applying these guidelines to an accepted technique of EF determination using a retrospective analysis of consecutive two‐dimensional echocardiographic studies performed on patients who had radioventriculography (RVG) within 48 hours. Using a 12 segment model, we scored each segment at the base and mid‐ventricular level based on segmental excursion and thickening. The apex was scored similarly but with 1/3 of the value based on a cylinder‐cone model. EF was determined from the sum of segment scores and was estimated visually. We termed this approach visual quantitative estimation (VQE). We correlated the EF derived from VQE and visual estimation with RVG EF. In the training set, VQE demonstrated a strong correlation with RVG

(r = 0.969)

, which was significantly greater than visual estimation

(r = 0.896, P < 0.01)

. The limits of agreement for VQE (+12% to −7%) were similar to the limits of RVG agreement with contrast ventriculography (+10% to −11%) with similar intraobserver and interobserver variabilities. Similar correlation was noted in the prediction set between VQE and RVG EF

(r = 0.967, P < 0.001)

. We conclude that VQE provides highly correlated estimates of EF with RVG. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Culture‐Negative Suppurative Endocarditis Causing Severe Mitral Valve Obstruction: Complementary Use of Transesophageal and Transthoracic Echocardiography
Authors: Roychoudhury Debasish , Chaithiraphan Vithaya , Stathopoulos Ioannis A. , Fergus Icilma , Tortolani Anthony , Murkis Marina A. , Messineo Frank
Published: June 2003

Infective endocarditis causes a myriad number of serious complications. Mitral valve obstruction is a rare complication. We report a 48‐year‐old Asian female who presented with two‐week duration of fever and rapidly developed acute pulmonary edema and cardiogenic shock. Sequential transthoracic and transesophageal echocardiography revealed a rapidly growing vegetation on the anterior mitral leaflet with severe stenosis of the valve. All the blood cultures were negative. The patient underwent a successful mitral valve replacement. A review of 21 previously reported cases of mitral valve obstruction from endocarditis demonstrates the poor prognosis of this entity and supports early surgery. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Utility of Hand‐Carried Ultrasound for Consultative Cardiology
Authors: Gorcsan John
Published: June 2003

Although the stethoscope has been an important part of the bedside cardiac diagnostic examination for generations of physicians, this clinical tool has been relatively unchanged in over 150 years. Echocardiography is established as an essential diagnostic imaging method for patients with known or suspected cardiovascular diseases. However, routine echocardiography systems are large and heavy, and although they are portable, they remain inconvenient for bedside patient rounds. Technologic advances have resulted in miniaturization of electronic components and small, lightweight ultrasound systems have been recently introduced. These hand‐carried units offer clinically acceptable two‐dimensional image quality for rapid “quick‐look” bedside diagnostics, in particular focusing on global and regional left ventricular function and presence or absence of pericardial effusion. This article proposes a general approach to the rapid hand‐carried ultrasound cardiac exam as an extension of the physical examination. It details case examples and reviews the initial clinical experience of hand‐carried ultrasound on cardiac consultation rounds. Hand‐carried ultrasound has promise to have an immediate impact on bedside patient management though expediting and facilitating the delivery of medical care. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Hand Carried Echocardiography in the Critical Care Setting
Authors: Spevack Daniel M. , Spevack Daniel M. , A. Tunick Paul , Kronzon Itzhak
Published: June 2003

Miniaturized echocardiography units known as hand carried ultrasound (HCU) now exist with features similar to those used for standard echocardiography. The small size and low cost of these units may lead to increased availability of echocardiography to be performed by all physicians taking care of critically ill patients. Use of HCU by critical care physicians may allow for improved bedside diagnosis with improved accuracy over physical examination. Studies comparing HCU with standard echocardiography in the critical care setting have reported that HCU is limited by decreased image quality and that it may miss important diagnoses even when used by experienced sonographers and echocardiographers. Despite its limitations, however, HCU can often answer important clinical questions in the critically ill. This review explores the current literature on the use of HCU in the critical care setting, discusses the limitations of HCU, and examines the costs of implementing this new technology. (ECHOCARDIOGRAPHY, Volume 20, July 2003)
Third International Workshop on Low-Temperature Physics in Microgravity Environment (CWS-2002)
Authors: Osip’yan Yu. A. , Mezhov-Deglin L. P.
Published: June 2003

The Third International Workshop on Low-Temperature Physics in Microgravity Environment (CWS-2002) was held at the Chernogolovka Research Center of the Russian Academy of Sciences from the twelfth through the eighteenth of August 2002. CWS-2002 was one of the satellite conferences and seminars devoted to some rapidly developing area of low-temperature physics which are traditionally held in conjunction with the International Conference on Low-Temperature Physics, which meets once every three years (LT-23 was held in Hiroshima, Japan on August 20–27, 2002). CWS-2002 was organized by the Institute of Solid State Physics of the Russian Academy of Sciences (ISSP RAS) and the Space Materials Science Section of the Space Council of the RAS, with the support of the RAS, the Ministry of Industry, Science and Technology of the Russian Federation, the Russian Foundation for Basic Research, and the Russian Aerospace Agency (Rosaviakosmos). We are also grateful to the Organizing Committee of LT-23 (especially to Prof. Shun-ichi Kobayashi and Dr. Kimitoshi Kono), the U.S. National Aeronautics and Space Administration (NASA) and Jet Propulsion Laboratory (JPL) (Dr. M. C. Lee and Dr. U. E. Israelsson), and to the INTAS foundation (Grant 02-MO-263, principal investigator Prof. L. Esquivias). At the Workshop, roundtable discussions were held with participants from the various projects supported by INTAS in 2001 and 2002.
Main fields of study in low-temperature physics and engineering on the Russian segment of the International Space Station
Authors: Anfimov N. A. , Luk’yashchenko V. I. , Suvorov V. V. , Tsimbalyuk M. M. , Bodin B. V.
Published: June 2003

The main trends in the evolutionary development of a long-term research program for the Russian segment of the International Space Station (RS ISS) are elaborated with allowance for the proposed changes in the final configuration of the ISS, the existing ideas about the conducting of joint experiments, and the desire of the scientific community for more efficient programs with real returns on the practical level. The main fields of study in low-temperature physics and engineering are analyzed.
An overview of the low temperature microgravity physics facility capabilities
Authors: Pensinger J. F. , Croonquist A. P. , Liu F. C. , Larson M. E. , Chui T. C.
Published: June 2003

The Low Temperature Microgravity Physics Facility currently in the design phase is a multiple user and multiple flight facility intended to provide a long duration low temperature environment onboard the International Space Station. The Facility will provide a unique platform for scientific investigations requiring both low temperature and microgravity conditions. It will be attached to the Japanese Experiment Module’s Exposed Facility and can house two science instruments each flight. The Facility consists of a 180-liter superfluid helium dewar, a support enclosure, and control electronics. The facility will be launched full of cryogen, and retrieved after the cryogen is depleted. Industrial partners are responsible for building the reusable facility and standard parts of the instruments. Principal Investigators from universities and other institutions are contracted to develop major parts of the science instrument package. An overview of the detailed technical capabilities of the facility will be presented in this paper.
Physical research on the effect of microgravity on physical phenomena in cryogenic liquids; a general purpose onboard cryogenic facility for implementing this research on the International Space Station
Authors: Bondarenko S. I. , Gavrylov R. V. , Eremenko V. V. , Rusanov K. V. , Shcherbakova N. S. , Dergunov I. M. , Kryukov A. P. , Korolyov P. V. , Selyaninova Yu. Yu. , Zhukov V. M. , Kharitonov V. S. , Kutsenko K. V. , Deev V. I. , Shuvalov V. A.
Published: June 2003

A combined research plan, called “Boiling,” is created on the basis of several cryogenic research projects developed by experts in Russia and Ukraine for the International Space Station. The “Boiling” plan includes eight initial experiments aimed at investigating the influence of microgravity on boiling, heat transfer, and hydrodynamics in liquid helium under normal or superfluid conditions. The experiments are supposed to be performed with individual cells all placed inside a single onboard cryogenic experimental facility. The experiments to be performed as part of the international research program have the following special features: several artificially simulated microgravity levels produced by rotating the experimental helium cryostat; visualization of the processes occurring in liquid helium; research on boiling and hydrodynamics in a large volume of stationary liquid and in a liquid flow through a channel. When the “Boiling” research plan is completed the onboard cryogenic facility created for the International Space Station should find applications in further scientific and experimental research with helium.
Technical integration of low-temperature research on the Russian segment of the ISS and optimization of the experiment packages
Authors: Buskin S. V. , Lukjashchenko V. I. , Repin I. Yu. , Suvorov V. V. , Shuvalov V. A. , Levitskiı̆ Yu. E.
Published: June 2003

The principle of integration of the low-temperature research planned for onboard the Russian segment of the International Space Station (ISS) is discussed in relation to the features of the cryogenic experiment packages, including the object of study and the cryostatic system. Systemic questions concerning the creation of a universal cryogenic laboratory on the orbital station for conducting deep-cooling experiments in the microgravity environment of space are examined. A block diagram of the laboratory is given, a classification of the equipment is presented, and the requirements on the experiment packages are discussed.
Short-range inverse-square law experiment in space
Authors: Strayer D. M. , Paik Ho Jung , Vol Moody M.
Published: June 2003

The objective of ISLES (inverse-square law experiment in space) is to perform a null test of Newton’s law on the ISS with a resolution of one part in 105 at ranges from 100 μm to 1 mm. ISLES will be sensitive enough to detect axions with the strongest allowed coupling and to test the string-theory prediction with R⩾5 μm. To accomplish these goals on the rather noisy International Space Station, the experiment is set up to provide immunity from the vibrations and other common-mode accelerations. The measures to be applied for reducing the effects of disturbances will be described in this presentation. As designed, the experiment will be cooled to less than 2 K in NASA’s low temperature facility the LTMPF, allowing superconducting magnetic levitation in microgravity to obtain very soft, low-loss suspension of the test masses. The low-damping magnetic levitation, combined with a low-noise SQUID, leads to extremely low intrinsic noise in the detector. To minimize Newtonian errors, ISLES employs a near-null source of gravity, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are suspended on the two sides of the source mass at a distance of 100 μm to 1 mm. The signal is detected by a supercon-ducting differential accelerometer, making a highly sensitive sensor of the gravity force generated by the source mass.
Thermal gravity-driven convection of near-critical helium in enclosures
Authors: Polezhaev V. I. , Soboleva E. B.
Published: June 2003

The results of a numerical simulation of Rayleigh–Bènard convection in He3 near the thermodynamic critical point are presented. The mathematical model includes the full Navier–Stokes equations with two-scale splitting of the pressure and the van der Waals equation of state. The existing experimental data on He are used in the simulation.  The “real”  Rayleigh3 and Prandtl numbers are estimated on the basis of the scaling laws. It is shown that to simulate the experiments more closely these “real” similarity criteria must concur for the physical media and the model. The Rayleigh number characterizing convection onset is determined from the calculations. This number is shown to be in good agreement with the existing experimental and theoretical values.
Boiling of He II in a porous structure in microgravity: a model representation
Authors: Dergunov I. M. , Korolev P. V. , Kryukov A. P. , Selyaninova Yu. Yu.
Published: June 2003

The results of a modeling of the boiling of superfluid helium in a microgravity environment are presented. The evolution of the vapor film on the surface of a cylindrical heater placed inside a thick-walled cylinder with porous walls is analyzed. The methods of molecular kinetic theory are used to describe the heat and mass transfer on the interphase surface. The equation of motion of the vapor–liquid interphase surface is solved. The influence of the parameters of the experiment on the characteristics of the vapor film is studied. The results of the calculation for microgravity and terrestrial environments are compared.
Quantum computing with bits made of electrons on a helium surface
Authors: Dahm A. J.
Published: June 2003

We describe a quantum computer based on electrons supported by a helium film and localized laterally by small electrodes. Each quantum bit (qubit) is made of combinations of the ground and first excited state of an electron trapped in the image potential well at the surface. Mechanisms for preparing the initial state of the qubit, operations with the qubits, and a proposed readout are described. This system is, in principle, capable of 105 operations in a decoherence time.
Manipulation of a He4 solid–liquid interface by acoustic radiation pressure
Authors: Nomura R. , Suzuki Y. , Kimura S. , Okuda Y. , Burmistov S.
Published: June 2003

Acoustic radiation pressure is thought to be very useful for solid He4 experiments under microgravity. We observed the manipulation of a He4 solid–liquid interface by an acoustic wave. We applied a sound pulse in a direction perpendicular to the flat interface between two transducers. At low temperatures the interface moved in the sound direction. We also checked how the interface moved when sound was applied parallel to the interface. The interface dynamics during and after the sound pulse were recorded with a high speed CCD camera.
Nonlinear second-sound waves in He4–3He superfluid mixtures
Authors: Kolmakov G. V.
Published: June 2003

The Hamiltonian formalism in two-fluid hydrodynamics is generalized to the case of He4–3He superfluid mixtures. The resulting formalism is used to calculate the amplitude of the three-wave interaction for second sound and the nonlinearity coefficient of second sound in He II with a He3 impurity. It is shown that the temperature at which the nonlinearity coefficient of the second sound changes sign from negative to positive is lowered from 1.88 to 1.7 K when a 10% He3 impurity is added to the superfluid He4. Thus for weak He4–3He solutions there exists a rather wide interval of temperatures below the superfluid transition temperature Tλ in which the nonlinearity coefficient of the second sound is negative, and the shock front is formed at the trailing edge of the nonlinear second-sound heating wave.
Proximity effect at a He II–He I interface under microgravity
Authors: Kiknadze L. , Mamaladze Yu.
Published: June 2003

The proximity effect is responsible for the existence of a transition region with graded variation of the superfluid component density instead of a sharp boundary at the level where the hydrostatic pressure induces a He II–He I phase transition. Under microgravity the characteristic length of this effect increases and the conditions become more conducive for performing measurements in the transition region. The problem of expanding the thermodynamic potential in a power series near a He II–He I interface is considered. The critical size of the superfluid region is determined.
Phonons and rotons of trapped atoms in a gravitational field
Authors: Baranov D. B. , Yarunin V. S.
Published: June 2003

The excitations of trapped atoms with a Bose–Einstein condensate in a trap are determined by the conservation of the total numbers of phonons and rotons of the atomic motion, and these properties depend on the presence of a gravitational field.
ESR investigation of hydrogen and deuterium atoms in impurity-helium solids
Authors: Kiselev S. I. , Khmelenko V. V. , Bernard E. P. , Lee D. M.
Published: June 2003

Impurity-helium solids (Im–He solids) are porous solids created by injecting a beam of mixed helium and impurity gases into superfluid He4. In this work we use electron spin resonance (ESR) techniques to investigate Im–He solids containing atoms and molecules of hydrogen and/or deuterium. We have performed studies of low temperature (T∼1.35 K) tunnelling chemical reactions in which deuterium atoms replace the hydrogen atoms bound in H2 or HD molecules to produce large (up to 7.5×1017 cm−3) and relatively stable concentrations of free hydrogen atoms. The time dependence of H and D atom concentrations has been investigated for Im–He samples with different initial ratios of hydrogen and deuterium ranging from 1:20 to 1:1. The satellite ESR lines associated with the dipolar coupling of electron spins of H and D atoms to the nuclear moments of the hydrogen nuclei found in neighboring molecules have been observed in Im–He solids. The forbidden hyperfine transition of atomic hydrogen involving the mutual spin flips of electrons and protons has also been observed.
On the formation mechanism of impurity–helium solids: evidence for extensive clustering
Authors: Popov E. A. , Eloranta J. , Ahokas J. , Kunttu H.
Published: June 2003

Optical emission studies of a discharged nitrogen–helium gas injected into superfluid helium near 1.5 K are described. Analysis of atomic (α group) and molecular Vegard–Kaplan transitions clearly indicates that the emitting species are embedded inside nitrogen clusters. Cluster formation is most efficient in the crater formed on the liquid surface. Model calculations based on the classical bubble model and density functional theory suggest that under the experimental conditions only clusters consisting of more than 1000 molecules have sufficient kinetic energy for stable cavity formation to occur inside liquid helium. The results obtained suggest that impurity–helium solids formation is a consequence of extensive clustering in the gas jet.
Gas-phase absorption properties of a green fluorescent protein-mutant chromophore: The W7 clone
Authors: Boyé Séverine , Nielsen Iben B. , Nielsen Steen B. , Krogh Helle , Lapierre Alain , Pedersen Henrik B. , Pedersen Steen U. , Pedersen Ulrik V. , Andersen Lars H.
Published: June 2003

The gas-phase absorption properties of a blue GFP-mutant chromophore have been investigated in an electrostatic heavy-ion storage ring combined with an electrospray ion source. From the production of neutral photofragments, the gas-phase absorption profiles of both protonated and deprotonated forms have been obtained and compared with their homologues in the liquid phase and in the protein. Maximum absorption for the anion is found around 456 nm in solution and in the gas phase. It matches one absorption maximum in the W7 protein, which suggests that this is due to an anionic form of the chromophore—similar to the case of the GFP. For the W7 chromophore cation, the gas-phase absorption band exhibits a doublet feature in the gas-phase with maxima at 454 and 477 nm. Solvation effects are more pronounced for the cation than for the anion and the observed shifts in the absorption maxima may be explained by charge delocalization.
Using C3v symmetry with polyspherical coordinates for methane
Authors: Wang Xiao-Gang , Carrington Tucker
Published: June 2003

It is well known that the group of operators that commutes with the Hamiltonian operator can be used to facilitate the calculation of energy levels. Due to numerical errors in the computation of Hamiltonian matrix elements, it may happen that the matrix representation of a group operator does not commute with the Hamiltonian matrix although the group operator does commute with the Hamiltonian operator. We demonstrate that it is possible, even in this case, to use the single-symmetry and multisymmetry symmetry-adapted Lanczos (SAL) methods to efficiently compute energy levels. The two SAL methods are applied to the calculation of the bend levels of methane using the G6 symmetry group and polyspherical angles. We show that although potential matrix elements are corrupted by quadrature error, it is nonetheless possible to take advantage of the full symmetry of the polyspherical basis. For a CX3Y-type molecule the symmetry-adapted method of this paper would enable one to exploit all of the symmetry of the molecule.
Exterior differential systems, Janet–Riquier theory and the Riemann–Lanczos problems in two, three, and four dimensions
Authors: Dolan P. , Gerber A.
Published: June 2003

We discuss the Riemann–Lanczos problems in two, three, and four dimensions using the theory of exterior differential systems and Janet–Riquier theory. We show that the Riemann–Lanczos problem in two dimensions is always a system in involution. For each of the two possible signatures we give the general solution in both instances and show that the occurrence of characteristic coordinates need not affect the result. In three dimensions, the Riemann–Lanczos problem is not in involution as an identity occurs. This does not prevent the existence of singular solutions and we give an example for the reduced Gödel space–time. A prolongation of this problem, whereby an integrability condition is added, leads to a prolonged system in involution. The Riemann–Lanczos problem in four dimensions is not in involution and needs to be prolongated as Bampi and Caviglia suggested. But singular solutions of it can be found and we give examples for the Gödel, Kasner, and Debever–Hubaut space–times.
The Weyl–Lanczos equations and the Lanczos wave equation in four dimensions as systems in involution
Authors: Dolan P. , Gerber A.
Published: June 2003

The Weyl–Lanczos equations in four dimensions form a system in involution. We compute its Cartan characters explicitly and use Janet–Riquier theory to confirm the results in the case of all space–times with a diagonal metric tensor and for the plane wave limit of space–times. We write the Lanczos wave equation as an exterior differential system and, with assistance from Janet–Riquier theory, we compute its Cartan characters and find that it forms a system in involution. We compare these Cartan characters with those of the Weyl-Lanczos equations. All results hold for the real analytic case.
Electric field induced second harmonic generation: Second and third-order hyperpolarizabilities of 4-amino-4′-nitrodiphenyl sulfoxide
Authors: Abdel-Halim Hamzeh M.
Published: June 2003

The second-order hyperpolarizability (β), and the third-order hyperpolarizability (γ) of 4-amino-4′-nitrodiphenyl sulfoxide (ANDSO) has been determined using the technique of electric field induced second harmonic (EFISH) generation in liquid. The third order macroscopic nonlinear susceptibility of ANDSO was first determined by comparing the intensity of the frequency doubled Nd:YAG laser pulse from the EFISH cell containing ANDSO solution to that of a reference material. The microscopic hyperpolarizabilities γ and β for ANDSO were extracted from the nonlinear susceptibility using local field factors, bond additivity concept and knowledge of the dipole moment of the molecule. Comparison of β and γ obtained in the present work to those obtained by other investigators for other molecules shows a superior microscopic nonlinear properties for ANDSO.