Distribution by Scientific Domains

Kinds of Research.

  • future research.

  • Selected Abstracts

    The VLA Low-frequency Sky Survey

    A. S. Cohen
    Abstract We present an overview of the ongoing VLA Low-frequency Sky Survey (VLSS, formerly known as 4MASS). The VLSS will map an area of 9.1 sr covering the entire sky above a declination of ,30 degrees (or 75% of the full sky), at a frequency of 74 MHz (4 meter wavelength) with an unprecedented combination of sensitivity and resolution at this low frequency. The observational challenges at this wavelength include radio frequency interference (RFI), ionospheric phase distortions and a large field of view filled with sources. These challenges have been surmounted by a variety of new algorithms. The principle data products from the survey will be a set of publicly available images along with a source catalog of approximately 80 000 objects. Thus we will create an online virtual observatory at this previously unexplored frequency which will complement other major surveys at higher frequencies such as the NVSS. The most efficient way currently know to search for high redshift radio galaxies is to select ultra steep spectrum sources from low frequency surveys. The VLSS represents an excellent opportunity to pursue this method with its unique combination of large sky coverage and very low frequency, which may be especially useful for finding objects at z > 5. The observations are now roughly 50% complete, and we expect to complete most of the rest by late 2005. Current data products and more information are available on our website (URL Basic research in radio astronomy at the Naval Research Laboratory is supported by the office of Naval Research. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Magnetic resonance spectroscopy (MRS) and its application in Alzheimer's disease

    Pravat K. Mandal
    Abstract Magnetic resonance spectroscopy (MRS) is a noninvasive tool to measure the chemical composition of tissues (in vivo) and characterize functional metabolic processes in different parts of the human organs. It provides vital biological information at the molecular level. Combined with magnetic resonance imaging (MRI), an integrated MRI/MRS examination provides anatomical structure, pathological function, and biochemical information about a living system. MRS provides a link between the biochemical alterations and the pathophysiology of disease. This article provides a comprehensive description of the MRS technique and its application in Alzheimer's disease (AD) research. This review is a primer for students and researchers seeking a firm theoretical understanding of MRS physics as well as its application in clinical AD research. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 40,64, 2007. [source]

    The cognitive phenotype of spina bifida meningomyelocele

    Maureen Dennis
    Abstract A cognitive phenotype is a product of both assets and deficits that specifies what individuals with spina bifida meningomyelocele (SBM) can and cannot do and why they can or cannot do it. In this article, we review the cognitive phenotype of SBM and describe the processing assets and deficits that cut within and across content domains, sensory modality, and material, including studies from our laboratory and other investigations. We discuss some implications of the SBM cognitive phenotype for assessment, rehabilitation, and research. © 2010 Wiley-Liss, Inc. Dev Disabil Res Rev 2010;16:31,39. [source]

    Pharmacogenetics of the neurodevelopmental impact of anticancer chemotherapy

    Philippe Robaey
    Abstract Pharmacogenetics holds the promise of minimizing adverse neurodevelopmental outcomes of cancer patients by identifying patients at risk, enabling the individualization of treatment and the planning of close follow-up and early remediation. This review focuses first on methotrexate, a drug often implicated in neurotoxicity, especially when used in combination with brain irradiation. The second focus is on glucocorticoids that have been found to be linked to adverse developmental effects in relation with the psychosocial environment. For both examples, we review how polymorphisms of genes encoding enzymes involved in specific mechanisms of action could moderate adverse neurodevelopmental consequences, eventually through common final pathways such as oxidative stress. We discuss a multiple hit model and possible strategies required to rise to the challenge of this integrative research. © 2008 Wiley-Liss, Inc. Dev Disabil Res Rev 2008;14:211,220. [source]

    Language development and fragile X syndrome: Profiles, syndrome-specificity, and within-syndrome differences

    Leonard Abbeduto
    Abstract Fragile X syndrome (FXS) is the leading inherited cause of mental retardation. In this article, we review what is known about the language and related problems of individuals with FXS. In doing so, we focus on the syndrome-specific features of the language phenotype and on the organismic (i.e., genetic and individual neurocognitive and behavioral) and environmental factors associated with within-syndrome variation in the phenotype. We also briefly review those aspects of the behavioral phenotype of FXS that are relevant for understanding syndrome-specific features of, and within-syndrome variability in, language. The review includes summaries of research on the prelinguistic foundations for language development and on each of the major components of language (i.e., vocabulary, morphosyntax, and pragmatics). Throughout the review, we point out implications of existing research for intervention as well as directions for future research. © 2007 Wiley-Liss, Inc. MRDD Research Reviews 2007;13:36,46. [source]

    Ultrasonic treatment of waste activated sludge

    Raf Dewil
    Abstract Activated sludge processes are key technologies to treat wastewater. These biological processes produce huge amounts of waste activated sludge (WAS), now commonly called biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. The ultrasonic treatment of WAS is quite novel. The present paper reports on extensive investigations using an ultrasonic treatment of WAS, to study its potential to meet one or all of four objectives: (1) reduce WAS quantities; (2) achieve a better dewaterability; (3) provoke a release of soluble chemical oxygen demand (COD) from the biosolids, preferably transformed into biodegradable organics; and (4) possibly destroy the filamentous microorganisms responsible for sludge bulking. Although meeting these objectives would help to solve the problems cited, the energy consumption could be a considerable drawback: the paper will thus assess whether all or some objectives are met, and at what operational cost. A literature survey defines the occurring phenomena (cavitation) and the important operation parameters [such as frequency, duration, specific energy input (SE)]. The experiments are carried out in a batch reactor of volume up to 2.3 L. The ultrasonic equipment consisted of a generator, a converter, and a sonotrode, supplied by Alpha Ultrasonics under the brand name of Telsonic. Three different kinds of sludge were tested, with different concentrations of dry solids (DS) between approximately 3.5 and 14 g DS/L WAS. Ultrasonic energy was introduced in a continuous manner (against possible pulsed operation). The major operational parameters studied include duration of the ultrasonic treatment and specific energy input. The applied frequency was set at 20 kHz. The release of COD from the WAS phase into the filtrate phase is a function of the specific energy input with yields of nearly 30% achievable at SE values of 30,000 kJ/kg DS. A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction in DS fraction of the sludge is proportional to the COD release rates. Although the DS content is reduced, the dewaterability of the sludge is not improved. This reflects itself in increased filtration times during vacuum filtration and in increased values of the capillary suction time (CST). This more difficult dewaterability is the result of considerably reduced floc sizes, offering an extended surface area: more surface water is bound (CST increases) and the filterability decreases as a result of clogging of the cake. To reach the same dryness as for the untreated cake, the required dosage of polyelectrolyte is nearly doubled when the SE of the ultrasound treatment is increased from 7500 to 20,000 kJ/kg DS. The ultrasonic reduction of filamentous WAS organisms is not conclusive and very little effect is seen at low intensities and short treatment durations. Microscopic analysis of the WAS identified the dominant presence of Actynomyces. The release of soluble COD and BOD certainly merit further research. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source]

    Speleothem preservation and diagenesis in South African hominin sites implications for paleoenvironments and geochronology

    Philip J. Hopley
    Plio-Pleistocene speleothems from australopithecine-bearing caves of South Africa have the potential to yield paleoenvironmental and geochronological information using isotope geochemistry. Prior to such studies it is important to assess the preservation of geochemical signals within the calcitic and aragonitic speleothems, given the tendency of aragonitic speleothems to recrystallize to calcite. This study documents the geochemical suitability of speleothems from the principal hominin-bearing deposits of South Africa. We use petrography, together with stable isotope and trace element analysis, to identify the occurrence of primary aragonite, primary calcite, and secondary calcite. This study highlights the presence of diagenetic alteration at many of the sites, often observed as interbedded primary and secondary fabrics. Trace element and stable isotopic values distinguish primary calcite from secondary calcite and offer insights into geochemical aspects of the past cave environment. ,13C values of the primary and secondary calcites range from +6 to ,9, and ,18O values range from ,4 to ,6,. The data are thus typical of meteoric calcites with highly variable ,13C and relatively invariant ,18O. High carbon isotope values in these deposits are associated with the effects of recrystallization and rapid outgassing of CO2 during precipitation. Mg/Ca and Sr/Ca ratios differ between primary and secondary calcite speleothems, aiding their identification. Carbon and oxygen isotope values in primary calcite reflect the proportion of C3 and C4 vegetation in the local environment and the oxygen isotope composition of rainfall. Primary calcite speleothems preserve the pristine geochemical signals vital for ongoing paleoenvironmental and geochronological research. © 2009 Wiley Periodicals, Inc. [source]

    Darwin would be proud: Bioturbation, dynamic denudation, and the power of theory in science

    D. L. Johnson
    Charles Darwin's worm book influenced many early researchers who, following his lead, demonstrated how soil biota mechanically generate new strata and soil horizons, as well as blur or destroy them. Such early observations on biomechanical processes failed to find visibility in our models of landscape evolution for several reasons, chief of which are (1) except for ichnology, an Earth sciences tradition of adopting frameworks where biomechanical processes are absent and (2) a lapse of over 100 years after Darwin before a genetic language backed by supporting theory appeared that could showcase the importance of such processes. Examples of influential Earth science frameworks in which biomechanical processes are absent are the V.V. Dokuchaev,USDA,H. Jenny soil formational (five factors) paradigm, W.M. Davis' geographical cycle, the W. Penck,L.C. King,R.V. Ruhe backwasting-pedimentation concept, the stratigraphic Law of Superposition, and other traditional approaches to archaeology, geomorphology, and pedology. Examples of recent genetic language that serve to ameliorate the problem are soil thickness concepts, biomantle, bioturbation, faunalturbation, floralturbation, and pedoturbation. Examples of recent supporting theory that incorporate biomechanical processes are soil evolution, biomantle evolution, dynamic pedogenesis, and the dynamic denudation framework advocated here. Dynamic denudation is a unified synthesis that elevates bioturbation to parity levels with other major archaeogenic, geomorphogenic, and pedogenic processes. The general framework and its principal elements are summarized and simulated by diagrams and augmented by photographs taken in disparate parts of the world. The model has useful explanatory and predictive value in archaeology, geomorphology, pedology, and other surficial process research. © 2002 John Wiley & Sons, Inc. [source]

    Temperature drop analysis of the thruster in a space cryogenic environment

    Ze-Juan Xiao
    Abstract Based on the conservation of energy, a coupling heat-transfer physical model and a set of mathematical equations are put forward to calculate the main components of the thruster, including the capillary injection tube, the aggregate organ, the injection plate, and the bracket when they are exposed to a space cryogenic environment. The typical temperature drop course of a 10N monopropellant thruster has been calculated by this computational model. The calculation results agree well with test data in a vacuum cryogenic simulation experiment performed on the ground. The temperature of the injection tube provides the thermal boundary conditions for the propellant temperature drop calculation while flowing through it. This provided the criterion to judge whether the propellant freezes or not. The upper stage has no air conditioning, so the injection tube is a weak link for the cryogenic reliability work of the thruster. This is considered one of the most important areas of the whole for reliability research. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(2): 85,95, 2007; Published online in Wiley InterScience ( DOI 10.1002/htj.20144 [source]

    Cellular and humoral autoimmunity directed at bile duct epithelia in murine biliary atresia,,

    HEPATOLOGY, Issue 5 2006
    Cara L. Mack
    Biliary atresia is an inflammatory fibrosclerosing lesion of the bile ducts that leads to biliary cirrhosis and is the most frequent indication for liver transplantation in children. The pathogenesis of biliary atresia is not known; one theory is that of a virus-induced, subsequent autoimmune-mediated injury of bile ducts. The aim of this study was to determine whether autoreactive T cells and autoantibodies specific to bile duct epithelia are present in the rotavirus (RRV)- induced murine model of biliary atresia and whether the T cells are sufficient to result in bile duct inflammation. In vitro analyses showed significant increases in IFN-,,producing T cells from RRV-diseased mice in response to bile duct epithelial autoantigen. Adoptive transfer of the T cells from RRV-diseased mice into naïve syngeneic SCID recipients resulted in bile duct,specific inflammation. This induction of bile duct pathology occurred in the absence of detectable virus, indicating a definite response to bile duct autoantigens. Furthermore, periductal immunoglobulin deposits and serum antibodies reactive to bile duct epithelial protein were detected in RRV-diseased mice. In conclusion, both cellular and humoral components of autoimmunity exist in murine biliary atresia, and the progressive bile duct injury is due in part to a bile duct epithelia,specific T cell,mediated immune response. The role of cellular and humoral autoimmunity in human biliary atresia and possible interventional strategies therefore should be the focus of future research. (HEPATOLOGY 2006;44:1231,1239.) [source]

    Applying cognitive adjustment theory to cross-cultural training for global virtual teams

    Julia Brandl
    Abstract Global virtual teams are faced with the challenge of developing trust in a technology-mediated context to overcome anxiety and uncertainty in their interactions. Research shows that adjustment is a function of an individual's ability to manage his or her anxiety and uncertainty in an unknown context (Gudykunst, 1995). We propose that the type of cross-cultural training (CCT) received can influence cognitive adjustment in global virtual teams. Building on phenomenology and sense-making theory, we argue that training needs to develop global virtual team members' capabilities in dealing with the unknown rather than providing ready-made concepts of cultures. Managerial implications of our theoretical discussion of cognitive adjustment and how CCT influences it are discussed, as are directions for future research. © 2009 Wiley Periodicals, Inc. [source]

    The effect of human resource management practices on the job retention of former welfare clients

    John R. Deckop
    Why should an employer hire a former welfare client?What human resource management practices can help employers retain former welfare clients? This study addresses these questions against the backdrop of changes in welfare legislation in the United States that have lessened support to welfare clients and their families and emphasized movement into the workplace. We conducted a large-scale empirical study of the effectiveness of a wide range of HRM practices and found that higher wages, better financial and health benefits, and development opportunities were positively associated with job retention. Unexpectedly, supervisory training had no relationship to retention, and appraising supervisors on providing a supportive and inclusive work environment showed a negative relationship. We provide suggestions to employers for improving the job retention of former welfare recipients along with directions for additional research. © 2006 Wiley Periodicals, Inc. [source]

    Understanding and optimizing multisource feedback

    Leanne E. Atwater
    This article integrates the most recent research results on the topic of multisource feedback with what researchers have learned over the years about performance feedback in general. We believe that this review and set of recommendations represent the state of the art at this time. We provide practitioners with new ideas about how to continue to improve the multisource feedback process in their organizations. We also suggest ideas for feedback providers and facilitators about how to maximize the success of the feedback process. Additionally, we provide "food for thought" for researchers concerning ideas for future research. © 2002 Wiley Periodicals, Inc. [source]

    International compensation practices: a ten-country comparative analysis

    Kevin B. Lowe
    This article presents a comparative study of compensation, by exploring nine items which measure pay and benefits practices in ten locations (nine countries and one region). First, similarities and differences in employee compensation are examined. Second, emerging issues for international compensation are identified. Third, gaps are identified between current practice and employee preferences for future compensation. Overall, the results of this study provide some support for previous research, although a number of counterintuitive findings are identified with respect to the ways in which culture might be expected to impact employee preferences for cross-cultural compensation practices. The research suggests several challenges for compensation practice and directions for future research. © 2002 Wiley Periodicals, Inc. [source]

    Scanning Probe Parallel Nanolithography with Multiprobe Cantilever Array Fabricated by Bulk Silicon Micromachining

    Hensy Gandjar Non-member
    Abstract This work describes a scanning probe parallel nanolithography (SPNL) technique for high throughput in nanometric patterning on single-crystal silicon (SCS) substrates. Two types of multiprobe cantilever arrays used for SPNL were fabricated by conventional micromachining. All the probes mounted on the free end of each cantilever were made of quasitrihedral pyramidal shape composed of (311) and (411) planes using the originally designed mask. Negative and positive types of nanolithography were performed on the basis of field-enhanced anodization and self-assembled monolayer mask techniques, respectively, and they succeeded in drawing a number of nanometric patterns of silicon dioxide (SiO2) on SCS substrates. After anisotropic wet etching of the SCS substrates using the SiO2 films as the mask material, we were also able to fabricate nanowires and nanogrooves. The effects of the applied voltage and scan time of cantilever arrays on wire and groove dimensions were systematically examined by atomic force microscopy (AFM) observations. An optimum condition for the parallel SPNL is proposed on the basis of this research. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Assessment, intervention, and research with infants in out-of-home placement

    Robert B. Clyman
    Infants constitute a large and increasing proportion of youth in out-of-home placement. These infants have very high rates of medical illnesses, developmental delays, and substantial risks for psychopathology. They receive varying amounts of services from a complex and poorly integrated service system that includes four principal service sectors: the child welfare, medical, early intervention, and mental health service sectors. These service systems are currently undergoing major changes in their policies, organization, and financing, such as the introduction of managed care into the child welfare system. In this article, we provide an overview of what is known about infants in out-of-home placement. We then summarize approaches to infant mental health assessment and intervention from a comprehensive perspective that addresses the infants' multiple problems and acknowledges that they need to receive services from multiple systems that are undergoing rapid change. We conclude by highlighting a number of critical areas in need of research. ©2002 Michigan Association for Infant Mental Health. [source]

    Misconduct in medical research: whose responsibility?

    K. J. Breen
    Abstract Examples of many types of misconduct in medical research continue to be reported. The true incidence is unknown because there is strong evidence of under-reporting as well as suggestions of increased detection. Risks to research participants may also be increasing, with contributing factors such as increased pressure on researchers to publish and to produce commercialization of their research. Institutions are perceived to typically respond slowly and inadequately to allegations of research misconduct. More could be done to try to prevent such mis­conduct, such as: (i) educating researchers about research ethics, (ii) assisting and protecting whistleblowers and (iii) instituting processes to adequately and promptly investigate and deal with allegations. In addition, a debate needs to take place as to whether research misconduct allegations should be dealt with at the institutional level or at a national level and whether medical boards should be routinely involved in the more serious breaches of ethical standards by medical practitioners engaged in research. (Intern Med J 2003; 33: 186,191) [source]

    Feeding and eating disorders in childhood

    Rachel Bryant-Waugh DPhil
    Abstract Objective: To review the literature related to the current DSM-IV-TR diagnostic criteria for feeding disorder of infancy or early childhood; pica; rumination disorder; and other childhood presentations that are characterized by avoidance of food or restricted food intake, with the purpose of informing options for DSM-V. Method: Articles were identified by computerized and manual searches and reviewed to evaluate the evidence supporting possible options for revision of criteria. Results: The study of childhood feeding and eating disturbances has been hampered by inconsistencies in classification and use of terminology. Greater clarity around subtypes of feeding and eating problems in children would benefit clinicians and patients alike. Discussion: A number of suggestions supported by existing evidence are made that provide clearer descriptions of subtypes to improve clinical utility and to promote research. © 2010 American Psychiatric Association. (Int J Eat Disord 2010) [source]

    Body image dissatisfaction and disordered eating in black and white women

    Marisol Perez
    Abstract Objective This study predicted and found that body image dissatisfaction and bulimic symptoms have a curvilinear relationship among undergraduate women. Results For the women in this sample, regardless of race, body image dissatisfaction correlated with bulimic symptoms, such that women who perceived themselves as bigger or smaller than the ideal body size for their ethnic group endorsed bulimic symptoms. Black and white women differed regarding their ethnic group's ideal body image and their self-perceptions of how they compared with the ideal image. Black women tended to report being underweight, whereas white women tended to report being overweight. Discussion The findings in this study suggest that some black women are not buffered against eating disorders as suggested in previous research. © 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 342,350, 2003. [source]

    Flexible models with evolving structure

    Plamen P. Angelov
    A type of flexible model in the form of a neural network (NN) with evolving structure is discussed in this study. We refer to models with amorphous structure as flexible models. There is a close link between different types of flexible models: fuzzy models, fuzzy NN, and general regression models. All of them are proven universal approximators and some of them [Takagi-Sugeno fuzzy model with singleton outputs and radial-basis function] are interchangeable. The evolving NN (eNN) considered here makes use of the recently introduced on-line approach to identification of Takagi-Sugeno fuzzy models with evolving structure (eTS). Both TS and eNN differ from the other model schemes by their gradually evolving structure as opposed to the fixed structure models, in which only parameters are subject to optimization or adaptation. The learning algorithm is incremental and combines unsupervised on-line recursive clustering and supervised recursive on-line output parameter estimation. eNN has potential in modeling, control (if combined with the indirect learning mechanism), fault detection and diagnostics etc. Its computational efficiency is based on the noniterative and recursive procedure, which combines the Kalman filter with proper initializations and on-line unsupervised clustering. The eNN has been tested with data from a real air-conditioning installation. Applications to real-time adaptive nonlinear control, fault detection and diagnostics, performance analysis, time-series forecasting, knowledge extraction and accumulation, are possible directions of their use in future research. © 2004 Wiley Periodicals, Inc. [source]

    The search for low energy conformational families of small peptides: Searching for active conformations of small peptides in the absence of a known receptor,

    Katrina W. Lexa
    Abstract Breast cancer is the most common cancer among women. Tamoxifen is the preferred drug for estrogen receptor-positive breast cancer treatment, yet many of these cancers are intrinsically resistant to tamoxifen or acquire resistance during treatment. Therefore, scientists are searching for breast cancer drugs that have different molecular targets. Previous work revealed that 8-mer and cyclic 9-mer peptides inhibit breast cancer in mouse and rat model systems, interacting with an unknown receptor, while peptides smaller than eight amino acids did not inhibit breast cancer. We have shown that the use of replica exchange molecular dynamics predicts structure and dynamics of active peptides, leading to the discovery of smaller peptides with full biological activity. These simulations identified smaller peptide analogs with a conserved turn, a ,-turn formed in the larger peptides. These analogs inhibit estrogen-dependent cell growth in a mouse uterine growth assay, a test showing reliable correlation with human breast cancer inhibition. We outline the computational methods that were tried and used with the experimental information that led to the successful completion of this research. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source]

    Some critical observations on twenty-first century graduate education in clinical psychology

    Gerald C. Davison
    A number of issues raised in the C.R. Snyder and T.R. Elliott article, "Twenty-First Century Graduate Education in Clinical Psychology: A Four Level Matrix Model" (this issue), are critically examined: the role of interpersonal and societal factors in understanding the human condition, the desirability of breadth in both undergraduate and graduate education, political and scientific issues in prevention research and application, problems in the use of randomized clinical trials for evaluating psychotherapy, and the efficacy,effectiveness debate in therapy research. © 2005 Wiley Periodicals, Inc. J Clin Psychol. [source]

    Trauma focus group therapy for combat-related PTSD: An update

    David W. Foy
    Individual cognitive,behavioral therapy involving directed exposure to memories of traumatic events has been found to be effective in treating posttraumatic stress disorder. In this article, we present updated information on an alternative group form of exposure therapy: manualized trauma-focus group therapy (TFGT), designed as an efficient means of conducting directed exposure. We describe the cognitive,behavioral and developmental models from which the approach was derived, present an overview of session topics and a case illustration, provide guidelines for referring individuals to TFGT, and offer suggestions for future research. © 2002 Wiley Periodicals, Inc. J Clin Psychol/In Session 58: 907,918, 2002. [source]

    Muscle stabilization strategies in people with medial knee osteoarthritis: The effect of instability

    Laura C. Schmitt
    Abstract The sensation of knee instability (shifting, buckling. and giving way) is common in people with medial knee osteoarthritis (OA). Its influence on knee stabilization strategies is unknown. This study investigated the influence of knee instability on muscle activation during walking when knee stability was challenged. Twenty people with medial knee OA participated and were grouped as OA Stable (OAS) (n,=,10) and OA Unstable (OAU) (n,=,10) based on self-reported knee instability during daily activities. Quadriceps strength, passive knee laxity, and varus alignment were assessed and related to knee instability and muscle cocontraction during walking when the support surface translated laterally. Few differences in knee joint kinematics between the groups were seen; however, there were pronounced differences in muscle activation. The OAU group used greater medial muscle cocontraction before, during, and following the lateral translation. Self-reported knee instability predicted medial muscle cocontraction, but medial laxity and limb alignment did not. The higher muscle cocontraction used by the OAU subjects appears to be an ineffective strategy to stabilize the knee. Instability and high cocontraction can be detrimental to joint integrity, and should be the focus of future research. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1180,1185, 2008 [source]

    Genetic marking with the ,LNGFR-gene for tracing goat cells in bone tissue engineering,

    M. C. Kruyt
    Abstract The use of bone marrow derived stromal cells (BMSC's) for bone tissue engineering has gained much attention as an alternative for autologous bone grafting. Little is known however, about the survival and differentiation of the cells, especially in the clinical application. The aim of this study was to develop a method to trace goat BMSC's in vivo. We investigated retroviral genetic marking, which allows stable expression of the label with cell division. Goat BMSC's were subjected to an amphotropic envelope containing a MoMuLV-based vector expressing the human low affinity nerve growth factor receptor (,LNGFR). Labeling efficiency and effect on the cells were analyzed. Furthermore, transduced cells were seeded onto porous ceramic scaffolds, implanted subcutaneously in nude mice and examined after successive implantation periods. Flow cytometry indicated a transduction efficiency of 40,60%. Immunohistochemistry showed survival and subsequent bone formation of the gene-marked cells in vivo. Besides, marked cells were also found in cartilage and fibrous tissue. These findings indicate the maintenance of the precursor phenotype following gene transfer as well as the ability of the gene to be expressed following differentiation. We conclude that retroviral gene marking with ,LNGFR is applicable to trace goat BMSC's in bone tissue engineering research. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

    Estimation of the aqueous solubility of organic compounds using molecular connectivity indices

    Chongli Zhong
    Abstract A correlation for estimation of the aqueous solubility of organic compounds that is based on a training set of 120 chemicals is proposed. The new model proposed is predictive and requires only molecular connectivity indices in the calculations. The calculated results of the new model are comparable to those from the existing general solubility equation (GSE) and the Klopman,Zhu models. The new model was also applied to a testing set of 80 compounds, and the predictions show that the new model is reliable with good predictive accuracy. Because the new model does not require any experimental physicochemical properties in the calculation, it is simple and easy to apply. This work shows again that molecular connectivity indices are useful structural descriptors in quantitative structure,property (QSPR) studies in pharmaceutical research. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2284,2294, 2003 [source]

    Reasoning from data: How students collect and interpret data in science investigations

    Zoe Kanari
    This study explored the understandings of data and measurement that school students draw upon, and the ways that they reason from data, when carrying out a practical science inquiry task. The two practical tasks used in the study each involved investigations of the relationships between two independent variables (IVs) and a dependent variable (DV); in both tasks, one IV covaried with the DV, whereas the other did not. Each was undertaken by 10 students, aged 10, 12, and 14 years (total n,=,60 students), working individually. Their actions were video-recorded for analysis. In a subsequent interview, each student was asked to discuss and interpret data collected by two other students, undertaking a similar (but different) practical task, shown on a video-recording. An analysis of the sample students' performance on the practical tasks and their interview responses showed few differences across task contexts, or with age, in students' reasoning, but significant differences in performance when investigating situations of covariation and non-covariation. Few students in the sample displayed sufficient understanding of measurement error to deal effectively with the latter. Investigations of non-covariation cases revealed, much more clearly than investigations of covariation cases, the students' ideas about data and measurement, and their ways of reasoning from data. Such investigations therefore provide particularly valuable contexts for teaching and research. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 748,769, 2004 [source]

    Stimulating a normal adjustment: Misbehavior, amphetamines, and the electroencephalogram at the bradley home for children

    Elizabeth Bromley
    This article uses an historical case study to describe the influence of social and contextual factors on the adoption of somatic approaches to children's misbehavior. The child guidance movement and the emergence of medicalized residential treatment facilities for children influenced the theoretical orientations of physicians treating children's behavior disorders in the United States in the 1930s. Charles Bradley and his colleagues at the Bradley Home in Rhode Island defined behavior disorders in social terms but investigated and treated misbehavior with somatic tools. The use of amphetamines and the electroencephalogram reorganized concepts of maladjustment along neurological lines, even as the research relied on the Home's social priorities. Electroencephalographic investigations especially shaped an organic concept of misbehavior. Ultimately, the somatic orientation obscured the central role of local context in Bradley Home physicians' research. © 2006 Wiley Periodicals, Inc. [source]

    Comparative proteomics analysis of human pituitary adenomas: Current status and future perspectives

    Xianquan Zhan
    Abstract This article will review the published research on the elucidation of the mechanisms of pituitary adenoma formation. Mass spectrometry (MS) plays a key role in those studies. Comparative proteomics has been used with the long-term goal to locate, detect, and characterize the differentially expressed proteins (DEPs) in human pituitary adenomas; to identify tumor-related and -specific biomarkers; and to clarify the basic molecular mechanisms of pituitary adenoma formation. The methodology used for comparative proteomics, the current status of human pituitary proteomics studies, and future perspectives are reviewed. The methodologies that are used in comparative proteomics studies of human pituitary adenomas are readily exportable to other different areas of cancer research. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:783,813, 2005 [source]

    Pathogenesis of medulloblastoma and current treatment outlook

    Jaroslaw Jozwiak
    Abstract Medulloblastoma is the most common malignant tumor of the cerebellum in children, with a tendency to metastasize via CSF pathway. Survival rate varies depending on several factors, but is rather favorable, with radiotherapy as the treatment of choice. Irradiation of the craniospinal axis results, however, in severe neuropsychological and psychosocial impairments pertaining to memory, attention, motor functioning, language, and visuospatial abilities. Precise mechanisms underlying the formation of medulloblastoma are still unclear, but implication of at least three signaling molecules is postulated: insulin-like growth factor-I, WNT, and Sonic hedgehog. Thanks to increasing knowledge on the cellular mechanisms contributing to tumor formation, it is possible to propose new therapies that could replace radiotherapy or allow decreasing irradiation doses. The current review presents recent developments in medulloblastoma pathophysiology research and proposed inhibitors that could constitute good candidates for further pharmacological research. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 6, 869,890, 2007 [source]