bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of the action of povidone-iodine against human and avian influenza A viruses: its effects on hemagglutination and sialidase activities
Authors: Sriwilaijaroen Nongluk , Wilairat Prapon , Hiramatsu Hiroaki , Takahashi Tadanobu , Suzuki Takashi , Ito Morihiro , Ito Yasuhiko , Tashiro Masato , Suzuki Yasuo
Published: August 2009

Background

Influenza virus infection causes significant morbidity and mortality and has marked social and economic impacts throughout the world. The influenza surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA), act cooperatively to support efficient influenza A virus replication and provide the most important targets for anti-influenza chemotherapy. In this study, povidone-iodine (PVP-I), which has a broad-spectrum microbicidal property, was examined for its inhibitory effects against influenza virus infection in MDCK cells and the mechanisms of PVP-I action on HA and NA were revealed.

Results

Results obtained using a novel fluorescence- and chromogenic-based plaque inhibition assay showed that 1.56 mg/ml PVP-I inhibited infections in MDCK cells of human (8 strains) and avian (5 strains) influenza A viruses, including H1N1, H3N2, H5N3 and H9N2, from 23.0–97.5%. A sialidase inhibition assay revealed that PVP-I inhibited N1, N2 and N3 neuraminidases with IC50 values of 9.5–212.1 μg/ml by a mixed-type inhibition mechanism. Receptor binding inhibition and hemagglutinin inhibition assays indicated that PVP-I affected viral hemagglutinin rather than host-specific sialic acid receptors.

Conclusion

Mechanisms of reduction of viral growth in MDCK cells by PVP-I involve blockade of viral attachment to cellular receptors and inhibition of viral release and spread from infected cells. Therefore, PVP-I is useful to prevent infection and limit spread of human and avian influenza viruses.
Multiple functions of precursor BDNF to CNS neurons: negative regulation of neurite growth, spine formation and cell survival
Authors: Koshimizu Hisatsugu , Kiyosue Kazuyuki , Hara Tomoko , Hazama Shunsuke , Suzuki Shingo , Uegaki Koichi , Nagappan Guhan , Zaitsev Eugene , Hirokawa Takatsugu , Tatsu Yoshiro , Ogura Akihiko , Lu Bai , Kojima Masami
Published: August 2009

Background

Proneurotrophins and mature neurotrophins elicit opposite effects via the p75 neurotrophin receptor (p75NTR) and Trk tyrosine kinase receptors, respectively; however the molecular roles of proneurotrophins in the CNS are not fully understood.

Results

Based on two rare single nucleotide polymorphisms (SNPs) of thehuman brain-derived neurotrophic factor (BDNF)gene, we generated R125M-, R127L- and R125M/R127L-BDNF, which have amino acid substitution(s) near the cleavage site between the pro- and mature-domain of BDNF. Western blot analyses demonstrated that these BDNF variants are poorly cleaved and result in the predominant secretion of proBDNF. Using these cleavage-resistant proBDNF (CR-proBDNF) variants, the molecular and cellular roles of proBDNF on the CNS neurons were examined. First, CR-proBDNF showed normal intracellular distribution and secretion in cultured hippocampal neurons, suggesting that inhibition of proBDNF cleavage does not affect intracellular transportation and secretion of BDNF. Second, we purified recombinant CR-proBDNF and tested its biological effects using cultured CNS neurons. Treatment with CR-proBDNF elicited apoptosis of cultured cerebellar granule neurons (CGNs), while treatment with mature BDNF (matBDNF) promoted cell survival. Third, we examined the effects of CR-proBDNF on neuronal morphology using more than 2-week cultures of basal forebrain cholinergic neurons (BFCNs) and hippocampal neurons. Interestingly, in marked contrast to the action of matBDNF, which increased the number of cholinergic fibers and hippocampal dendritic spines, CR-proBDNF dramatically reduced the number of cholinergic fibers and hippocampal dendritic spines, without affecting the survival of these neurons.

Conclusion

These results suggest that proBDNF has distinct functions in different populations of CNS neurons and might be responsible for specific physiological cellular processes in the brain.
Mechanism of action of lenalidomide in hematological malignancies
Authors: Kotla Venumadhav , Goel Swati , Nischal Sangeeta , Heuck Christoph , Vivek Kumar , Das Bhaskar , Verma Amit
Published: August 2009

Immunomodulatory drugs lenalidomide and pomalidomide are synthetic compounds derived by modifying the chemical structure of thalidomide to improve its potency and reduce its side effects. Lenalidomide is a 4-amino-glutamyl analogue of thalidomide that lacks the neurologic side effects of sedation and neuropathy and has emerged as a drug with activity against various hematological and solid malignancies. It is approved by FDA for clinical use in myelodysplastic syndromes with deletion of chromosome 5q and multiple myeloma. Lenalidomide has been shown to be an immunomodulator, affecting both cellular and humoral limbs of the immune system. It has also been shown to have anti-angiogenic properties. Newer studies demonstrate its effects on signal transduction that can partly explain its selective efficacy in subsets of MDS. Even though the exact molecular targets of lenalidomide are not well known, its activity across a spectrum of neoplastic conditions highlights the possibility of multiple target sites of action.
Development and initial validation of the Bedside Paediatric Early Warning System score
Authors: Parshuram Christopher S , Hutchison James , Middaugh Kristen
Published: August 2009

Introduction

Adverse outcomes following clinical deterioration in children admitted to hospital wards is frequently preventable. Identification of children for referral to critical care experts remains problematic. Our objective was to develop and validate a simple bedside score to quantify severity of illness in hospitalized children.

Methods

A case-control design was used to evaluate 11 candidate items and identify a pragmatic score for routine bedside use. Case-patients were urgently admitted to the intensive care unit (ICU). Control-patients had no 'code blue', ICU admission or care restrictions. Validation was performed using two prospectively collected datasets.

Results

Data from 60 case and 120 control-patients was obtained. Four out of eleven candidate-items were removed. The seven-item Bedside Paediatric Early Warning System (PEWS) score ranges from 0–26. The mean maximum scores were 10.1 in case-patients and 3.4 in control-patients. The area under the receiver operating characteristics curve was 0.91, compared with 0.84 for the retrospective nurse-rating of patient risk for near or actual cardiopulmonary arrest. At a score of 8 the sensitivity and specificity were 82% and 93%, respectively. The score increased over 24 hours preceding urgent paediatric intensive care unit (PICU) admission (P < 0.0001). In 436 urgent consultations, the Bedside PEWS score was higher in patients admitted to the ICU than patients who were not admitted (P < 0.0001).

Conclusions

We developed and performed the initial validation of the Bedside PEWS score. This 7-item score can quantify severity of illness in hospitalized children and identify critically ill children with at least one hours notice. Prospective validation in other populations is required before clinical application.
Cholesterol-dependent cytolysins induce rapid release of mature IL-1β from murine macrophages in a NLRP3 inflammasome and cathepsin B-dependent manner
Authors: Chu Jessica , Thomas L Michael , Watkins Simon C , Franchi Luigi , Núñez Gabriel , Salter Russell D
Published: August 2009

This study explores the mechanism by which a bacterial toxin induces the secretion of a proinflammatory cytokine from innate immune cells.

CDC are exotoxins secreted by many Gram-positive bacteria that bind cholesterol and oligomerize to form pores in eukaryotic cell membranes. We demonstrate that CDC TLO induces caspase-1 cleavage and the rapid release of IL-1β from LPS-primed murine BMDM. IL-1β secretion depends on functional toxin pore formation, as free cholesterol, which prevents TLO binding to cell membranes, blocks the cytokine release. Secretion of the mature forms of IL-1β and caspase-1 occurs only at lower TLO doses, whereas at a higher concentration, cells release the biologically inactive proforms. IL-1β release at a low TLO dose requires potassium efflux, calcium influx, and the activities of calcium-independent PLA2, caspase-1, and cathepsin B. Additionally, mature IL-1β release induced by a low TLO dose is dependent on the NLRP3 inflammasome, and pro-IL-1β release induced by a high TLO dose occurs independently of NLRP3. These results further elucidate a mechanism of CDC-induced IL-1β release and suggest a novel, immune evasion strategy in which IL-1β-containing macrophages might release primarily inactive cytokine following exposure to high doses of these toxins.
Receptor tyrosine phosphatases control tracheal tube geometries through negative regulation of Egfr signaling
Authors: Jeon Mili , Zinn Kai
Published: August 2009

The formation of epithelial tubes with defined shapes and sizes is essential for organ development. We describe a unique tracheal tubulogenesis phenotype caused by loss of both Drosophila type III receptor tyrosine phosphatases (RPTPs), Ptp4E and Ptp10D. Ptp4E is the only widely expressed Drosophila RPTP, and is the last of the six fly RPTPs to be genetically characterized. We recently isolated mutations in Ptp4E,and discovered that, although Ptp4E null mutants have no detectable phenotypes, double mutants lacking both Ptp4E and Ptp10D display synthetic lethality at hatching owing to respiratory failure. In these double mutants,unicellular and terminal tracheal branches develop large bubble-like cysts that selectively incorporate apical cell surface markers. Cysts in unicellular branches are enlargements of the lumen that are sealed by adherens junctions,whereas cysts in terminal branches are cytoplasmic vacuoles. Cyst size and number are increased by tracheal expression of activated Egfr tyrosine kinase,and decreased by reducing Egfr levels. Ptp10D forms a complex with Egfr in transfected cells. Downregulation of Egfr signaling by the RPTPs is required for the construction of tubular lumens, whether extracellular or intracellular, by cells that undergo remodeling during branch morphogenesis. The Ptp4E Ptp10D phenotype represents the first evidence of an essential role for RPTPs in epithelial organ development. These findings might be relevant to organ development and disease in mammals, because PTPRJ(DEP-1), an ortholog of Ptp4E/Ptp10D, interacts with the hepatocyte growth factor receptor tyrosine kinase. PTPRJ corresponds to the murine Scc1(suppressor of colon cancer) gene.
Vegetally localized Xenopus trim36 regulates cortical rotation and dorsal axis formation
Authors: Cuykendall Tawny N. , Houston Douglas W.
Published: August 2009

Specification of the dorsoventral axis in Xenopus depends on rearrangements of the egg vegetal cortex following fertilization, concomitant with activation of Wnt/β-catenin signaling. How these processes are tied together is not clear, but RNAs localized to the vegetal cortex during oogenesis are known to be essential. Despite their importance, few vegetally localized RNAs have been examined in detail. In this study, we describe the identification of a novel localized mRNA, trim36, and characterize its function through maternal loss-of-function experiments. We find that trim36 is expressed in the germ plasm and encodes a ubiquitin ligase of the Tripartite motif-containing (Trim) family. Depletion of maternal trim36 using antisense oligonucleotides results in ventralized embryos and reduced organizer gene expression. We show that injection of wnt11 mRNA rescues this effect, suggesting that Trim36 functions upstream of Wnt/β-catenin activation. We further find that vegetal microtubule polymerization and cortical rotation are disrupted in trim36-depleted embryos, in a manner dependent on Trim36 ubiquitin ligase activity. Additionally, these embryos can be rescued by tipping the eggs 90° relative to the animal-vegetal axis. Taken together, our results suggest a role for Trim36 in controlling the stability of proteins regulating microtubule polymerization during cortical rotation, and subsequently axis formation.
Myosin II regulation duringC. elegansembryonic elongation:LET-502/ROCK, MRCK-1 and PAK-1, three kinases with different roles
Authors: Gally Christelle , Wissler Frédéric , Zahreddine Hala , Quintin Sophie , Landmann Frédéric , Labouesse Michel
Published: August 2009

Myosin II plays a central role in epithelial morphogenesis; however, its role has mainly been examined in processes involving a single cell type. Here we analyze the structure, spatial requirement and regulation of myosin II during C. elegans embryonic elongation, a process that involves distinct epidermal cells and muscles. We developed novel GFP probes to visualize the dynamics of actomyosin remodeling, and found that the assembly of myosin II filaments, but not actin microfilaments, depends on the myosin regulatory light chain (MLC-4) and essential light chain (MLC-5, which we identified herein). To determine how myosin II regulates embryonic elongation,we rescued mlc-4 mutants with various constructs and found that MLC-4 is essential in a subset of epidermal cells. We show that phosphorylation of two evolutionary conserved MLC-4 serine and threonine residues is important for myosin II activity and organization. Finally, in an RNAi screen for potential myosin regulatory light chain kinases, we found that the ROCK, PAK and MRCK homologs act redundantly. The combined loss of ROCK and PAK, or ROCK and MRCK, completely prevented embryonic elongation, but a constitutively active form of MLC-4 could only rescue a lack of MRCK. This result, together with systematic genetic epistasis tests with a myosin phosphatase mutation,suggests that ROCK and MRCK regulate MLC-4 and the myosin phosphatase. Moreover, we suggest that ROCK and PAK regulate at least one other target essential for elongation, in addition to MLC-4.
Association of serum glycated albumin to haemoglobin A1C ratio with hepatic function tests in patients with chronic liver disease
Authors: Bando Yukihiro , Kanehara Hideo , Toya Daisyu , Tanaka Nobuyoshi , Kasayama Soji , Koga Masafumi
Published: August 2009

Background

In patients with chronic liver disease (CLD), glycated haemoglobin (HbA1C) levels have been shown to be apparently lower than real values, whereas serum glycated albumin (GA) levels are apparently higher. The present study was aimed to examine whether both glycaemic indices are influenced by hepatic function.

Methods

Subjects consisted of 82 patients with CLD. Various indicators for hepatic function as well as HbA1C and GA were also measured. Estimated HbA1C values were calculated from the mean plasma glucose levels. Two hundred and two type 2 diabetic patients without CLD were studied as controls.

Results

Although GA was strongly correlated with HbA1C in patients with CLD as well as diabetic patients, GA levels in patients with CLD were relatively higher than those in diabetic patients. In patients with estimated HbA1C ≤5.8%, GA levels significantly increased but HbA1C levels decreased as a function of decreasing hepaplastin test (HPT). The ratio of GA/HbA1C (G/H ratio) increased as a function of decreasing HPT. In patients with estimated HbA1C >5.8%, in contrast, GA levels were independent of HPT levels. In the patients with CLD, GA and HbA1C were associated with mean plasma glucose levels and some indicators for hepatic function. The multivariate analysis revealed a significant association of G/H ratio with HPT, cholinesterase and direct bilirubin. The G/H ratio was not associated with the mean plasma glucose but with HPT and cholinesterase levels.

Conclusions

The G/H ratio correlates with hepatic function but not with plasma glucose levels. Therefore, CLD should be suspected for diabetic patients with an elevated G/H ratio.
The diagnosis and investigation of adrenal insufficiency in adults
Authors: Wallace Ian , Cunningham Sean , Lindsay John
Published: August 2009

There is considerable variation in the methods used to diagnose and investigate adrenal insufficiency in clinical practice. These include a range of adrenocorticotropin (ACTH) stimulation and other dynamic testing protocols, serum cortisol cut-off values for diagnosis and tests used for differential diagnosis. With the introduction of modern cortisol and ACTH assays, the interpretation of tests used for diagnosis and differential diagnosis has become more complex and requires local validation. This review examines the basis of normal hypothalamic–pituitary–adrenal axis function and adrenal insufficiency states based upon an evidence base accumulated over the past four decades. The role of the laboratory in the differential diagnosis and interpretation based upon assay methodology is discussed. The accurate identification of patients who may benefit from corticosteroid replacement in special settings such as critical illness is challenging and will be explored.
Multiple Risks and Mean-Variance Preferences
Authors: Eichner Thomas , Wagener Andreas
Published: August 2009

We analyze comparative static effects under uncertainty when a decision maker has mean-variance preferences and faces a generic, quasi-linear decision problem with both an endogenous risk and a background risk. In terms of mean-variance preferences, we fully characterize the effects of changes in the location, scale, and concordance parameters of the stochastic environment on optimal risk taking. Presupposing compatibility between the mean-variance and the expected-utility approach, we then translate these mean-variance properties into their analogues for von Neumann-Morgenstern utility functions.
Technical Note—Price Trends in a Dynamic Pricing Model with Heterogeneous Customers: A Martingale Perspective
Authors: Xu Xiaowei , Hopp Wallace J.
Published: August 2009

This note describes probabilistic properties of optimal price sample paths in a dynamic pricing model with a finite horizon and limited stock. We assume that customer arrivals follow a nonhomogeneous Poisson process. We show that if customers' willingness-to-pay increases rapidly over time, then the optimal price process follows a submartingale, which implies an upward price trend. Alternatively, if customers' willingness-to-pay decreases rapidly over time, then the optimal price process follows a supermartingale, which implies a downward price trend.
Short- and Long-Term Risk Stratification Using a Next-Generation, High-Sensitivity Research Cardiac Troponin I (hs-cTnI) Assay in an Emergency Department Chest Pain Population
Authors: Kavsak Peter A , Wang Xuesong , Ko Dennis T , MacRae Andrew R , Jaffe Allan S
Published: August 2009

Background: The next-generation, high-sensitivity cardiac troponin assays can measure quantifiable concentrations of cTn in a majority of individuals, but there are few studies assessing these assays for risk stratification. The present study was undertaken to determine if a research hs-cTnI assay can be useful for predicting death/myocardial infarction (MI), both short- and long-term, in an emergency department acute coronary syndrome (ACS) population.

Methods: In a cohort of 383 subjects, originally recruited in 1996, presenting to the emergency department with symptoms suggestive of ACS, the heparin plasma obtained at initial presentation was thawed and measured in 2007 with a research hs-cTnI assay. AccuTnI (Beckman Coulter) measurements were made on these same samples in 2003. The population was divided into 4 groups by hs-cTnI: <5.00, 5.00–9.99, 10.00–40.00, and >40.00 ng/L. Kaplan–Meier, Cox proportional hazards, ROC curves, and logistic regression analyses were used to identify which hs-cTnI concentrations were predictive of death/MI within 10 years after presentation.

Results: There were significant differences between the hs-cTnI groups for the probability of death/MI up to 10 years after presentation (P < 0.05). At 6 months, patients with hs-cTnI ≥10.00 ng/L were at higher risk for death/MI (hazard ratio >3.7; P < 0.05) compared with those having hs-cTnI <5.00 ng/L. ROC curve analysis for death/MI at 30 days with the hs-cTnI assay had an area under the curve of 0.74 (95% CI 0.65–0.82), with logistic models yielding an optimal assay threshold of 12.68 ng/L.

Conclusions: This research hs-cTnI assay appears useful for risk stratification for death/MI in an ACS population.
On the streets and on the road: identity in transit in TurkishGerman travelogues on screen
Authors: Burns Rob
Published: August 2009

As with the iconography of exilic and diasporic cinema generally, the TurkishGerman cinema of the 1970s and 1980s featured images of captivity and claustrophobic spaces. More recently, in tandem with a shift away from the tendency to represent the migrant as victim, this cinema has
portrayed its protagonists as on the move, either within urban environments or in transit between Turkey and Germany. Focusing primarily on this last category of film, the article will examine the significance attaching to such transnational journeys. In some cases they serve mainly as a means
of narrative closure in the form of enforced (or even self-imposed) deportation; while in genuine road movies the journey from Turkey to Germany may be represented in miserabilist terms as one of pain and despair or more positively as one of quest and self-assertion. In Fatih Akin's films,
particularly In July, Head-On and The Edge of Heaven, where the protagonists journey in the reverse direction (from Germany to Turkey), transnational travel entails a quest either for redemption or for new forms of identity.
From Turkish greengrocer to drag queen: reassessing patriarchy in recent TurkishGerman coming-of-age films
Authors: Berghahn Daniela
Published: August 2009

This article explores the critical reassessment of one particularly prevalent ethnic stereotype in TurkishGerman cinema: the stereotype of the oppressive Turkish partriarch. Comparing Yasemin (1988), a much-cited, early coming-of-age film made by German film-maker Hark Bohm,
with three recent features made by young TurkishGerman film-makers Slbiye Gnar's Karamuk (2002), Ayse Polat's Tour Abroad and Zli Aladag's controversial Rage (2006) it examines fatherdaughter and fatherson relationships and traces how these films reaffirm or invert the
clichd image of the domineering Turkish father who is out of touch with German majority culture. Drawing on Kobena Mercer's concept of the dialogic imagination, the article investigates whether these cinematic representations of the vilified or idealized father promote social change through
a multiplication of critical dialogues or whether they simply reiterate dominant discourses of domination (Mercer 2003).
Surveillance during labour
Authors: Steer Philip J.
Published: August 2009

The technology of intrapartum surveillance made rapid strides from the 1960s through the 1980s but then stagnated as increasing resort to caesarean section was made rather than improving measures of fetal condition and labour progress. However, despite caesarean section rates commonly over 30%, medicolegally expensive mistakes continue to be made because it is difficult to teach clinicians to make reliable use of existing technology. It may be that as with aircraft navigation, the safest solution is to replace human judgement with the obstetric equivalent of automatic pilots.
Limit of viability in Japan: ethical consideration
Authors: Nishida Hiroshi , Sakuma Izumi
Published: August 2009

Viability means “the quality or state of being able to live, grow and develop.” Limit of viability has been changed along with the advancement of perinatal and neonatal medicine. The viability limit defined in the Japanese Motherhood Protection Act was amended from 24 to 22 completed weeks of gestation in 1991 based on the survival rate of extremely preterm infants. Survival rates of infants at 22 and 23 weeks' gestation born between 2002 and 2004 in Japan were 31% and 56%, respectively. Though medical data are the most important means to define viability, socio-economical and ethical factors should be also considered, especially when we discuss the group of marginally viable infants. We think there are two different categories of viability limits, one from biological survival limit and another from social agreement of providing active medical intervention. Currently in Japan, the former viability definition based on purely medical data is 22 completed weeks and the latter definition is the social consensus of about 24–28 weeks' gestation.
Indicators of compliance for developmental follow-up of infants discharged from a regional NICU
Authors: Nehra Vedika , Pici Maria , Visintainer Paul , Kase Jordan S.
Published: August 2009

Aim: To identify factors associated with compliance of scheduled outpatient developmental follow-up appointments in an effort to better ensure future care.

Methods: This retrospective observational cohort study looked at patients born between January 7th 2006 and June 30th 2007 and discharged from a regional neonatal intensive care unit (RNICU). Discharge summaries were reviewed to attain information regarding 16 patient descriptives and 12 patient morbidities. Data were recorded and analyzed utilizing the statistical software SPSS 11.5.

Results: Children of older mothers were more likely to attend follow-up (compliant: 30 years vs. non-compliant: 27 years). Factors which significantly improved compliance with follow-up care were patient contact after discharge (compliant: 65% vs. non-compliant: 35%) and early intervention referral (compliant: 64% vs. non-compliant: 36%). Factors which significantly hindered compliance were maternal drug use during pregnancy (compliant: 11.8% vs. non-compliant: 88%), and patient transfer to outside NICUs [(transferred out: compliant: 3 (10.3%), non-compliant 25 (89.3%)].

Conclusions: Several factors associated with compliance have been identified. Direct patient contact after discharge positively correlated with improved follow-up attendance. The severity of patient disease in the NICU did not impact follow-up rates. As a result close attention needs to be paid to factors which influence compliance with outpatient follow-up for developmental screening.
A new obstetrical polyurethane versus stainless steel forceps: a comparison of forces generated to the base of the fetal skull during simulated deliveries
Authors: Hale Theodore M. , Shi Zhengzhuan , Idangodage Hasitha , Mercado Ray , Skupski Daniel , Veilastegui Zoila
Published: August 2009

Background: Decreasing the maximum force applied during traction to the base of the fetal skull using a less rigid polyurethane forceps is the basis of this study. Our hypothesis was that less force would be generated with polyurethane forceps than with steel forceps.

Objective: To test a new soft polyurethane obstetrical forceps for maximal force generated to the base of the skull during simulated occiput anterior deliveries and to compare this to a similar shaped steel forceps.

Methods: After designing a prototype polyurethane forceps, we used a pelvic manikin model and a fetal manikin model. Force and load sensors were attached at the inner tips of the distal forceps blade. A Tekscan 201 (accurate for measuring 0–25 pounds of force) 0.0008 inches flexible printed circuit was used that measured contact forces. Forceps with an attached calibrated sensor were applied to the fetal head while inside the pelvic model.

Results: The median maximum traction force at the base of the fetal skull was 4.60 pounds (range 4.3–4.62) for polyurethane forceps vs. 9.52 pounds (range 9.22–9.52) for steel forceps (P=0.027).

Conclusion: The polyurethane forceps applied 50% less overall mechanical force than the steel forceps at the tip of the forceps and base of the skull during simulated occiput anterior outlet deliveries.
Utility of two-dimensional echocardiography in pregnancy and post-partum period and impact on management in an inner city hospital
Authors: Dharmarajan Lekshmi , Hale Theodore M. , Velastegui Zoila , Castillo Emerita , Kanna Balavenkatesh
Published: August 2009

Aim: Evaluate the practice and appropriateness of requesting echocardiograms in patients with suspected or documented cardiac disease during gestation and puerperium, using the American College of Cardiology Foundation (ACCF) appropriateness criteria, in conjunction with clinical picture.

Methods: Retrospective observational study, to analyze echocardiograms performed during pregnancy and puerperium at a teaching hospital from 2001 to 2006 for appropriateness criteria and studying its impact on management. Sixty-seven patients pregnant or in the puerperal stage had an echocardiogram performed during that period; 58 met our criteria for inclusion.

Results: Based on clinical information and criteria of the ACCF, 51 of the 58 echocardiograms met the appropriateness criteria. Of the 51, results of 40 impacted on management; 14 of the 40 echocardiograms that had an impact were abnormal.

Conclusions: Although the ACCF appropriateness criteria have not been specifically studied in pregnancy, our study demonstrates that the criteria are applicable if used appropriately in pregnancy. Most indications in our study correlated with the appropriateness criteria. Although most findings were normal, information from echocardiograms impacted on management in the majority of patients, contributing to therapeutic decision-making. The reliability of echocardiograms performed according to appropriate criteria to assist clinical decisions was excellent even in patients with physiologic cardiovascular changes.
Adaptive Strategies of Remote Systems Operators Exposed to Perturbed Camera-Viewing Conditions
Authors: Stuart Mark A. , Manahan Meera K. , Bierschwale John M. , Sampaio Carlos E. , Legendre A. Jay
Published: August 2009

Perturbed camera views (e.g., reversed, inverted/reversed, inverted) will often be the primary mode of visual feedback for remote manipulator operators during the assembly, maintenance, and servicing of NASA's existing as well as future space craft and installations. This report describes a preliminary investigation of the use of perturbed visual feedback during the performance of simulated space-based remote manipulation tasks. The primary objective of this NASA evaluation was to determine to what extent operators exhibit adaptive strategies which allow them to perform these specific types of remote manipulation tasks more efficiently while exposed to perturbed visual feedback. A secondary objective of this evaluation was to establish a set of preliminary guidelines for enhancing remote manipulation performance and reducing the adverse effects. These objectives were accomplished by studying the remote manipulator performance of test subjects exposed to various perturbed camera-viewing conditions while performing a simulated space-based remote manipulation task. Statistical analysis of performance and subjective data revealed that remote manipulation performance was adversely affected by the use of perturbed visual feedback and performance tended to improve with successive trials in most perturbed viewing conditions. Information gathered in this study was then used to develop a set of adaptive strategies which can serve as an aid in the training of future remote systems operators and a set a preliminary guidelines concerning remotely operated systems design (e.g., camera placement, control system development, and workstation design).
Workload or Situational Awareness?: TLX vs. SART for Aerospace Systems Design Evaluation
Authors: Selcon S.J. , Taylor R.M. , Koritsas E.
Published: August 2009

Both workload and situational awareness (SA) have been recognised as important considerations in aerospace system design evaluation. This paper considers the use of subjective techniques for the measurement of workload and SA, namely the NASA TLX workload scale and the Situational Awareness Rating Technique (SART), and compares the diagnosticity and sensitivity of each within a computer-graphics flight simulation environment. Both the 10-dimensional and 3-dimensional implementations of SART were tested. Twelve RAF pilots were asked to rate a videotape of an air combat flight simulation sequence, using the TLX and SART techniques. Task difficulty was varied between the flight sequences used. The experimental group was split according to their flying experience. Task difficulty and experience were analysed as the main independent variables in the experiment. Results showed that although both scales were sensitive to task difficulty, only SART showed any differences between experience conditions. This implies that SART may have some added utility where operator capability or domain expertise is a design variable. Intercorrelations showed a substantial overlap between the two scales on a number of factors. These factors are discussed to attempt to clarify both differences and similarities between the scales, and also the degree of commonality between the concepts of workload and SA. The implications of such differences are considered within the application domain of aerospace systems design and evaluation.
Target Designation in a Perspective View, 3-D Map Using a Joystick, Hand Tracker, or Voice
Authors: Barthelemy Kristen K. , Reising John M. , Hartsock David C.
Published: August 2009

The purpose of this study was to determine which of three cursor control techniques would provide the best means of designating targets in three-dimensional space. The three techniques tested were a joystick, a hand tracker, and voice. The current study showed that the quickest and most accurate target designations occurred when using the hand tracker, and when targets were positioned in the front most part of the three-dimensional volume.
A Systems Analysis to Identify Human Factors Issues and Requirements for Data Link
Authors: Riley Victor
Published: August 2009

When developing a complex system, it is often difficult to identify the human factors issues and requirement areas associated with the system. We have developed a systematic methodology to identify human factors issues and requirement areas based on an information flow model of the system, the form of which is determined by a taxonomy of automation. We have tested the methodology on an analysis of data link, which is a communications technology intended to replace much of the air-to-ground voice communications in commercial transport aircraft. Our analysis addresses such areas as what factors may contribute to errors and what the effects of those errors may be, Cockpit Resource Management (CRM) effects and requirements, pilot and air traffic controller situation awareness and workload, and the design of the Human-Computer Interface (HCI). The analysis has brought to light a number of potentially critical issues that have not yet been addressed in the data link literature. Although the analysis does not yield quantitative system design requirements, it does lead to extensive and detailed qualitative requirement areas that may then be used to drive a System Requirements Document and guide empirical research. It is also relatively simple and inexpensive to perform.
Up/Down in (Im)possible Flight Attitude Indicators - Some Effects of Colour, Shape and Pattern -
Authors: Dahlstedt Sven
Published: August 2009

Based upon general complaints from pilots, as well as suspicions that misinterpretations of the flight attitude indicator(FAI) had contributed to some crashes, some research was initiated. The first studies concerned minor revisions of the layout of the current electromechanical spherical FAI. The results indicated that many pilots wanted some improvements of the FAI and that the present colour combination (black and white) could not be considered optimal for the Swedish pilot population.

The studies were continued with more hypothetical constructs, aiming at finding possible coding principles for future computer-generated flight attitude information. The basic idea was to try to find some visual coding dimension(s) that would trigger spontaneous interpretations of the spatial up/down dimension.

In a series of experiments a number of combinations of colours, shapes and patterns were tested on both volontary civilian subjects and military pilots. It was found that most of the tested people expressed very strong spatial associations to some of the combinations, but also that the agreement between individuals sometimes was practically negligible. Colour and shape tended to elicit the strongest responses, with the tested patterns acting more as minor moderators. Unfortunately, however, the large individual differences do not indicate that the design of a single “optimal” combination would be easy.
Headphone Localization of Speech Stimuli
Authors: Begault Durand R. , Wenzel Elizabeth M.
Published: August 2009

Recently, three-dimensional acoustic display systems have been developed that synthesize virtual sound sources over headphones based on filtering by Head-Related Transfer Functions (HRTFs), the direction-dependent spectral changes caused primarily by the outer ears. Here, 11 inexperienced subjects judged the apparent spatial location of headphone-presented speech stimuli filtered with non-individualized HRTFs. About half of the subjects “pulled” their judgements toward either the median or the lateral-vertical planes, and estimates were almost always elevated. Individual differences were pronounced for the distance judgements; 15 to 46% of stimuli were heard inside the head with the shortest estimates near the median plane. The results infer that most listeners can obtain useful azimuth information from speech stimuli filtered by non-individualized HRTFs. Measurements of localization error and reversal rates are comparable with a previous study that used broadband noise stimuli.
Electronic Map Interpretation in a Dual-Task Context
Authors: Williams Henry P. , Wickens Christopher D.
Published: August 2009

The present experiment was designed to assess the extent to which spatial and verbal-analytic (VA) information processing resources are used in performing a simulated aircraft navigation task. Subjects were required to decide whether a “match” or a “mismatch” existed between a schematic 3D perspective forward field of view and a 2D top-down map. On dual-task trials, this navigation task was concurrently performed with either a VA side-task or with one of two tracking tasks. The data suggest that a VA strategy was most likely to be used when stimuli were simple or were mismatches, whereas a spatial mental rotation strategy was apparently used to confirm complex match stimuli. These results indicate that it may be possible to specify conditions wherein navigation is likely to compete for resources critical to other cockpit activities, such as aircraft control and communication.
The National Plan for Aviation Human Factors: Maintenance Research Issues
Authors: Johnson William B.
Published: August 2009

The National Plan for Aviation Human Factors addresses Human Factors research associated with pilots, controllers, maintenance technicians, and their respective work environments. In each of the sections the plan addresses issues related to topics such as automation and advanced technology, basic scientific knowledge about human performance, information transfer, performance measurement, training and selection, and certification.

This paper describes the portions of the National Plan related to maintenance. It includes discussion of problems shared in the maintenance of aircraft and in the maintenance of the “electronic highways” called airway facilities. The paper describes the Plan's research recommendations. In addition the paper elaborates on the current Office of Aviation Medicine Human Factors in Aviation Maintenance research, associated with the National Aging Aircraft Research Program.
Evaluating Robot Procedures and Tasks for the Flight Telerobotic Servicer
Authors: Sauerwein Timothy A. , Molino John A.
Published: August 2009

NASA is developing space telerobotic systems to construct, service and maintain complex space hardware. These systems will be controlled by an astronaut operator in space. Preliminary mission procedures have been developed and typical task elements have been selected. The present study simulates some of these procedures, tasks and devices in the laboratory in order to obtain initial operator/robot system performance data.
HUD Climb/Dive Ladder Configuration and Unusual Attitude Recovery
Authors: Weinstein Lisa F. , Ercoline William R.
Published: August 2009

Twelve head-up display (HUD) experienced pilots participated in a study that examined the effects of articulated lines versus parallel, tapered lines in the top and bottom halves of the climb/dive ladder for recovering from nose-down unusual attitudes in a flight simulator. These configurations were assessed using a moving climb/dive marker (CDM) on half of the trials and a fixed pitch reference for the remaining trials. The results indicated that the climb/dive ladder configuration did not affect a pilot's reaction time to initiate a recovery. However, in terms of accuracy of the initial, significant stick input, the articulated lines in the bottom half of the HUD with a moving CDM resulted in significantly poorer performance (about 12% worse) than that associated with the other three configurations. Subjective data suggest that pilots preferred the articulated lines in the bottom half of the HUD even though their preferences did not correlate with their performance. These findings suggest that articulated lines in the bottom half of the HUD are detrimental to a pilot's ability to recover from nose-down unusual attitudes.
Response to an Automated Function Failure Cue: An Operational Measure of Complacency
Authors: Knapp Robert K. , Vardaman Jennifer J.
Published: August 2009

This report describes an experiment whose purpose was to operationally define complacency. Non-pilots performed an airspeed and altitude maintenance task on a desktop approach procedures trainer, while responding to three unpredictable reaction time cues each minute during a 20 minute trial. A separate reaction time cue was yoked to come on with this cue and extinguish automatically with it; but subjects were instructed that they had to respond to this second cue if it failed to extinguish by itself. This otherwise irrelevant cue simulated an automated function whose persistence signaled a system failure and called for detection and response on the part of the subject. The delay in response to this “complacency” probe, compared with the latencies of the ongoing reaction time task, comprised the measure of complacency. Complacency reaction time was significantly longer and, while a second complacency probe led to improved response times, evidence for complacency persisted. Non-pilot subjects tended to keep the trainer within 100 feet of the assigned altitude, and within 10 knots of the assigned airspeed. There was no evidence of degradation of performance of either the flying tasks or the reaction times as a function of time-sharing.
Microstructural Characterization of RPV Materials Irradiated to High Fluences at High Flux
Authors: Soneda Naoki , Dohi Kenji , Nishida Kenji , Nomoto Akiyoshi , Tomimatsu Minoru , Matsuzawa Hiroshi
Published: August 2009

Understanding the embrittlement of reactor pressure vessel (RPV) steels at high fluence region is very important for the long term operation of nuclear power plants. In this study, extensive microstructural analyses were performed on the RPV steels irradiated to very high fluences beyond 1020n/cm2, E>1 MeVat high fluxes under the Pressurized Thermal Shock and Nuclear Power Plant Integrity Management projects in Japan. Three dimensional atom probe analyses were performed to characterize the solute atom cluster formation in these materials. The effects of fluence, flux, and chemical compositions on the characteristics of clusters were analyzed. The formation of dislocation loops was identified in the transmission electron microscopy analyses of high and low Cu steels, and the changes in loop size and number density with fluence were studied. P segregation on grain boundaries was also studied by surface analyses as well as grain boundary chemical analyses. We found that nonhardening embrittlement due to grain boundary fracture is not a major contributor to the embrittlement in these materials and irradiation conditions. The correlation of the microstructural changes and the Charpy transition temperature shifts was studied. The volume fraction of solute atom clusters has an excellent correlation with the transition temperature shifts. The Orowan model calculations of the contributions of dislocation loops to the transition temperature shifts show that in low Cu materials, dislocation loops may be a major contributor, but in Cu containing materials its contribution is weak. Root-sum-square of the contributions of solute atom clusters and dislocation loops seems to be a reasonable model to describe the total ΔRTNDT.
Adaptation of the Micro-Deval Test for Assessing the Surface Weathering Degree of Granite
Authors: Takarli Mokhfi , Phelipot-Mardele Annabelle , Prince William
Published: August 2009

The paper summarizes recent results obtained from a new wear test performed on fresh and artificially aged rocks. Four different types of granitic rocks with different mineral compositions and grain sizes were selected for this study. Some important physical and mechanical properties of the rock specimens were also determined. Measurements performed on fresh specimens showed that the wear coefficient is affected by the mineralogical composition, especially the predominant mineral which constitutes the rock. It was determined that wear resistance increased with increasing quartz content. The results also show that there is a positive correlation between the micro-fragmentation rate, during the wear test, and the average grain sizes. Two specimens of the tested granites were subjected to an artificial hydro-physical ageing test. Based on the results of the experiment, it was concluded that the wear testing method is a good indicator of the weathering degree. It was shown that the imposed weathering process decreases the abrasion resistance of the rock and increases its micro-fragmentation ability.
High Pressure Quick Disconnect Particle Impact Tests
Authors: Rosales Keisa R. , Stoltzfus Joel M.
Published: August 2009

National Aeronautics and Space Administration (NASA) Johnson Space Center White Sands Test Facility (WSTF) performed particle impact testing to determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the environmental control and life support system (ECLSS) on the International Space Station (ISS). Testing included standard supersonic and subsonic particle impact tests on 15–5 PH stainless steel, as well as tests performed on a QD simulator. This paper summarizes the particle impact tests completed at WSTF. Although there was an ignition in test series 4, it was determined that the ignition was caused by the presence of a machining imperfection. The sum of all the test results and analysis enabled NASA to conclude that the risk of particle impact ignition hazard in the ISS ECLSS QDs was acceptable.