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Several Problems (several + problem)
Selected AbstractsAn element-wise, locally conservative Galerkin (LCG) method for solving diffusion and convection,diffusion problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2008C. G. Thomas Abstract An element-wise locally conservative Galerkin (LCG) method is employed to solve the conservation equations of diffusion and convection,diffusion. This approach allows the system of simultaneous equations to be solved over each element. Thus, the traditional assembly of elemental contributions into a global matrix system is avoided. This simplifies the calculation procedure over the standard global (continuous) Galerkin method, in addition to explicitly establishing element-wise flux conservation. In the LCG method, elements are treated as sub-domains with weakly imposed Neumann boundary conditions. The LCG method obtains a continuous and unique nodal solution from the surrounding element contributions via averaging. It is also shown in this paper that the proposed LCG method is identical to the standard global Galerkin (GG) method, at both steady and unsteady states, for an inside node. Thus, the method, has all the advantages of the standard GG method while explicitly conserving fluxes over each element. Several problems of diffusion and convection,diffusion are solved on both structured and unstructured grids to demonstrate the accuracy and robustness of the LCG method. Both linear and quadratic elements are used in the calculations. For convection-dominated problems, Petrov,Galerkin weighting and high-order characteristic-based temporal schemes have been implemented into the LCG formulation. Copyright © 2007 John Wiley & Sons, Ltd. [source] Finite-element simulation of incompressible fluid flow in an elastic vesselINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2003Harry Y. H. Chen Abstract Finite-element simulation was performed to predict the incompressible Navier,Stokes flow in a domain, partly bounded by an elastic vessel, which is allowed to vary with time. Besides satisfying the physical conservation laws, both surface and the volume conservation laws are satisfied at the discrete level for ensuring the balance between physical and geometrical variables. Several problems which are amenable to analytical solutions were tested for validating the method. The simulated results are observed to agree favourably with analytical solutions. Having verified the applicability of the finite-element code to problems involving moving grids, we consider an incompressible fluid flow bounded by rigid and elastic vessel walls. Our emphasis was placed on the validation of the formulation developed within the moving-grid framework. Copyright © 2003 John Wiley & Sons, Ltd. [source] Fabrication of Precise Fluidic Structures in LTCCINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2009Fred Barlow A number of emerging applications of low-temperature co-fired ceramic (LTCC) require embedded fluidic structure within the co-fired ceramic and or precise external dimensional tolerances. These structures enable the control of fluids for cooling, sensing, and biomedical applications, and variations in their geometry from the design can have a significant impact on the overall performance of the devices. One example of this type of application is a multilayer cooler developed recently by the authors for cooling laser diode bars. In many laser systems, laser diodes are the primary emitters, or assemblies of these diode bars are used to pump traditional laser crystals such as Nd:YLF. Assemblies of these diodes require large amounts of electrical current for proper operation, and the device operating temperature must be carefully controlled in order to avoid a shift in the output wavelength. These diodes are packaged into water-cooled assemblies and by their nature dissipate enormous amounts of heat, with waste heat fluxes on the order of 2000 W/cm2. The traditional solution to this problem has been the development of copper multilayer coolers. Assemblies of laser diodes are then formed by stacking these diode bars and coolers. Several problems exist with this approach including the erosion of the copper coolers by the coolant, a requirement for the use of deionized water within the system, and a significant CTE mismatch between the diode bar and the metal cooler. Diodes are bonded to these metal structures and liquid coolant is circulated through the metal layers in order to cool the diode bar. In contrast, the coolers developed by the authors utilize fluid channels and jets formed within LTCC as well as embedded cavity structures to control the flow of a high-velocity liquid and actively cool the laser diode bars mounted on the surface of the LTCC., The dimensional tolerances of these cooler assemblies and complex shapes that are used to control the fluid can have a significant impact on the overall performance of the laser system. This paper describes the fabrication process used to create the precise channel and jet structures used in these LTCC-based coolers, as well as some of the challenges associated with these processes. [source] The use of size,frequency diagrams to characterize prehistoric fish catches and to assess human impact on inshore fisheriesINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1-2 2001Foss Leach Abstract Archaeological collections of fish bones from previously excavated sites in New Zealand are being re-examined and selected bones measured in order to estimate original fish size, reconstruct prehistoric fish catches and assess human impact on the fishery over the course of about 800 years of New Zealand prehistory. Several problems hamper this research, such as small sample sizes, lack of significant stratigraphy at many sites, inconsistent field collection strategies and failure to retain all of the material after initial analysis. Although some common fish species show a significant decline in mean size between pre-European and early historic samples on the one hand, and modern populations on the other, we have found little support for the common belief that there was a decline in mean fish size during the pre-European period. We have observed increases over time in the mean size of snapper (Pagrus auratus), blue cod (Parapercis colias) and undifferentiated species of Labridae from several sites scattered throughout New Zealand. Distinguishing between changes in fish population structures owing to natural processes, such as surface sea water changes, and those which are the result of human over-fishing is not simple, because both processes can operate simultaneously. We draw on modern fish quota management models to separate these processes. Important factors for each species are inshore biomass and the recruitment rate at different temperature regimes. In the case of blue cod, we find that there are signs in the catch diagrams of changes in fishing technology, and that 30,80% of catches are undersized fish in terms of modern management criteria. Copyright © 2001 John Wiley & Sons, Ltd. [source] The Many Facets of Identity CriteriaDIALECTICA, Issue 2 2004Massimiliano Carrara The aim of this note is to discuss the general form and role of identity criteria. We have taken two readings into consideration which express two different functions of identity criteria. The first expresses the epistemic function whilst the second deals with the ontological function. We argue that there are several problems related to the specification of both these functions. As a consequence, we conclude that identity criteria are not necessary to provide ontological legitimacy. [source] PERORAL PANCREATOSCOPY: CURRENT STATUS AND FUTURE EXPECTATIONS USING NARROW BAND IMAGINGDIGESTIVE ENDOSCOPY, Issue 2007Yoshifumi Arisaka Peroral pancreatoscopy (POPS) under duodenoscopic assistance provide direct visual assessment of the pancreatic duct, tissue sampling, and therapeutic interventions. Sometimes, pancreatoscopy can confirm accurate diagnosis, such as differential diagnosis of filling defects between intraductal tumors and stones. However, it is often difficult to differentiate malignant from benign strictures solely on pancreatoscopy. It is currently considered that intraductal papillary mucinous neoplasm (IPMN) is the most suitable indication of POPS. POPS has several problems: image resolution, fragility and maneuverability. Concerning image resolution, the quality has been improved with the development of a video pancreatoscope. Moreover, the recently developed endoscopic optical technology of narrow band imaging (NBI) is now available to video pancreatoscopy. This will allow direct visual assessment. Although currently POPS has several problems, further improvement will assist POPS to become a useful modality in combination with NBI. [source] Composite Multienzyme Amperometric Biosensors for an Improved Detection of Phenolic CompoundsELECTROANALYSIS, Issue 22 2003B. Serra Abstract A biosensor design, in which glucose oxidase and peroxidase are coimmobilized by simple physical inclusion into the bulk of graphite-Teflon pellets, is reported for the detection of phenolic compounds. This design allows the "in situ" generation of the H2O2 needed for the enzyme reaction with the phenolic compounds, which avoids several problems detected in the performance of single peroxidase biosensors as a consequence of the presence of a high H2O2 concentration. So, a much lower surface fouling was found at the GOD-HRP biosensor in comparison with a graphite-Teflon-HRP electrode, suggesting that the controlled generation of H2O2 makes more difficult the formation of polymers from the enzyme reaction products. The construction of trienzyme biosensors, in which GOD, HRP and tyrosinase were coimmobilized into the graphite-Teflon matrix is also reported, and their performance was compared with that of GOD-HRP bienzyme electrodes. The practical applicability of the composite multienzyme amperometric biosensors was evaluated by the estimation of the phenolic compounds content in waste waters from a refinery, and the results were compared with those obtained by using a colorimetric official method based on the reaction with 4-aminoantipyrine. [source] Service restoration method considering simultaneous disconnection of distributed generators by one-bank fault of distribution systemELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2008Hirotaka Takano Abstract Distributed generators (DGs) such as fuel cells and solar cells are going to be installed in the demand side of distribution systems. The DGs can reduce distribution loss by appropriate allocation. However, there are several problems installing DGs such as service restoration of distribution system with DGs and so on. When one bank fault of distribution substation occurs in distribution system, since DGs are simultaneously disconnected from the system, it is not easy to restore isolated load by one bank switching in distribution substation. Therefore, a service restoration method to determine restoration configuration and restoration procedures (switching procedure from normal configuration to restoration configuration) taking into account simultaneous disconnection of DGs is needed. In this paper, the authors propose a computation method to determine the optimal restoration configuration and the restoration procedure considering simultaneous disconnection of DGs by one bank fault of distribution system. In the proposed algorithm, after all of the restoration configuration candidates are effectively enumerated under the operational constraints, the optimal configuration to restore the isolated load is selected among enumerated configuration candidates. After determining the optimal restoration configuration, the optimal restoration procedures are obtained by greedy algorithm. Numerical simulations are carried out for a real scale system model with 237 sectionalizing switches (configuration candidates are 2237) and 21 DGs (total output is 5250 kW which is 3% of total load) in order to examine the validity of the proposed algorithm. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(8): 44,55, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10133 [source] Collaboration, facilities and communities in day care services for older peopleHEALTH & SOCIAL CARE IN THE COMMUNITY, Issue 1 2001Sarah Burch BA Abstract Collaborative working in care for older people is often seen as a desirable goal. However, there can be problems with this approach. This paper reports on a single blind randomized controlled trial which was carried out to compare outcomes of rehabilitation in two settings: a day hospital and social services day centres augmented by visiting therapists. The subjects were 105 older patients. Principal outcome measures were the Barthel Index, Philadelphia Geriatric Centre Morale Scale and the Caregiver Strain Index. Two aspects of the trial are examined here. Firstly, we investigated whether trial patients were more disabled than regular day centre attendees. Levels of health and well being amongst trial patients were compared with those of a random sample of 20 regular attendees from both of the participating day centres and an additional voluntary sector day centre. Secondly, key staff from the different settings were interviewed to assess how well the day centre model had worked in practice. Trial patients were significantly more disabled than regular day centre attendees according to the Barthel Index (P < 0.001), but this difference was no longer significant after three months of treatment. The day centre model had several problems, principally discharge policy, acceptability, facilities and attitudes of staff and regular attendees. Positive aspects of the day centre model, as well as successful rehabilitation, included shared skills, knowledge and resources. This paper suggests that collaborative working in day centres requires multipurpose facilities. If health staff maintain a permanent presence, benefits can include improved joint working, easier access to health care and the use of rehabilitative therapy as a preventative strategy. Day care settings can be analyzed as representing different types of communities. Allowing older users a greater degree of choice in facilities may increase the acceptability of care. [source] Development of a knowledge-based system for nonpowered hand tools (Tool Expert): Part I,The scientific basisHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 3 2004Berman Kayis The need for developing a clear and concise guide for designing, selecting, and using hand tools would minimize if not eliminate acute,chronic trauma exposure factors and help improve efficiency, well-being, and morale. Despite several research efforts devoted to the exploration and understanding of the interrelation between human capabilities, task requirements, nature of tasks, and ergonomically designed hand tools, there appear to be several problems in utilizing existing knowledge in practical use. One of the most important barriers is the lack of interaction of several specialists from different backgrounds. In this article, TOOL-EXPERT, a knowledge-based system developed to assert the ergonomical nonpowered hand tool design, selection, and use, is explained, which will provide a guideline to several users from various backgrounds. The system is designed to run in any IBM-compatible personal computer system. Knowledge from several domains was included. The type of knowledge used in the research was selected to be a declarative knowledge. Altogether it includes 423 goals, 35 questions, and 40 rules. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 257,268, 2004. [source] Three-dimensional elastoplastic analysis by triple-reciprocity boundary element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 8 2007Yoshihiro Ochiai Abstract In general, internal cells are required to solve elastoplastic problems using a conventional boundary element method (BEM). However, in this case, the merit of BEM, which is ease of data preparation, is lost. Triple-reciprocity BEM can be used to solve two-dimensional elastoplasticity problems with a small plastic deformation. In this study, it is shown that three-dimensional elastoplastic problems can be solved, without the use of internal cells, by the triple-reciprocity BEM. An initial strain formulation is adopted and the initial strain distribution is interpolated using boundary integral equations. A new computer program was developed and applied to solving several problems. Copyright © 2006 John Wiley & Sons, Ltd. [source] Meshless thermo-elastoplastic analysis by triple-reciprocity boundary element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 13 2010Yoshihiro OchiaiArticle first published online: 18 SEP 200 Abstract In general, internal cells are required to solve thermo-elastoplasticity problems by a conventional boundary element method (BEM). However, in this case, the merit of BEM, which is the easy preparation of data, is lost. A conventional multiple-reciprocity boundary element method (MRBEM) cannot be used to solve elastoplasticity problems, because the distribution of initial strain or stress cannot be determined analytically. In this study, it is shown that without the use of internal cells, two-dimensional thermo-elastoplasticity problems can be solved by a triple-reciprocity BEM using a thin plate spline. Initial strain and stress formulations are adopted and the initial strain or stress distribution is interpolated using boundary integral equations. A new computer program was developed and applied to solve several problems. Copyright © 2009 John Wiley & Sons, Ltd. [source] A conservative integral for bimaterial notches subjected to thermal stressesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2004Leslie Banks-Sills Abstract In this investigation, a conservative integral based on the Betti reciprocal principle is developed to obtain stress intensity factors for a bimaterial notch in which the body is subjected to a thermal load. The bonded materials are linear elastic, isotropic and homogeneous. According to the linear theory of elasticity, stresses in the neighbourhood of the notch tip are generally singular as a result of the mismatch of the elastic constants. Eigenvalues and eigenfunctions depend upon the mechanical properties and wedge angles. They may be real, complex or power-logarithmic. Real and complex eigenvalues are considered in this study. The stress intensity factor represents the amplitude of the stress singularity and depends upon material properties, geometry and load or temperature. Because of the highly singular behaviour of one of the integrals that is part of the conservative integral, the former is carried out by a hybrid analytical/numerical scheme. The finite element method is employed to obtain displacements caused by the temperature distribution in the body. The conservative integral is applied to several problems appearing in the literature. Both good agreement between those results and the ones obtained here, as well as path stability for all problems is attained. A wide range of material parameters is also studied. Copyright © 2004 John Wiley & Sons, Ltd. [source] A new modification of the immersed-boundary method for simulating flows with complex moving boundariesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2006Jian Deng Abstract In this paper, a new immersed-boundary method for simulating flows over complex immersed, moving boundaries is presented. The flow is computed on a fixed Cartesian mesh and the solid boundaries are allowed to move freely through the mesh. The present method is based on a finite-difference approach on a staggered mesh together with a fractional-step method. It must be noted that the immersed boundary is generally not coincident with the position of the solution variables on the grid, therefore, an appropriate strategy is needed to construct a relationship between the curved boundary and the grid points nearby. Furthermore, a momentum forcing is added on the body boundaries and also inside the body to satisfy the no-slip boundary condition. The immersed boundary is represented by a series of interfacial markers, and the markers are also used as Lagrangian forcing points. A linear interpolation is then used to scale the Lagrangian forcing from the interfacial markers to the corresponding grid points nearby. This treatment of the immersed-boundary is used to simulate several problems, which have been validated with previous experimental results in the open literature, verifying the accuracy of the present method. Copyright © 2006 John Wiley & Sons, Ltd. [source] Relational problems and psychiatric symptoms in couple therapyINTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 4 2005Ann-Marie Lundblad This article describes couples attending family counselling in Sweden. The study group is compared with clinical groups and non-clinical groups. Self-rating instruments were com-pleted by 317 women and 312 men to evaluate the following: marital satisfaction (DAS), expressed emotion (QAFM), family climate (FC), psychiatric symptoms (SCL-90) and sense of coherence (SOC). This group had several problems: marital relationships, disrupted family functioning, dyadic interactions characterised by criticism and open arguments, and multiple psychological symptoms. The women were espe-cially discontent in the relationship, and they exhibited higher symptom strain and lower sense of coherence than the men did. Compared with non-clinical populations, this group was severely distressed and was similar to in-patient families in child psychiatric clinics. The low sense of coherence of the individuals in the group under study means that their sense of having a meaningful life and their ability to comprehend and manage problems were severely compromised. Adequate and comprehensive treatment within the framework of social pro-grammes should be made available to these couples and others in a similar situation. [source] Pests, pesticide use and alternative options in European maize production: current status and future prospectsJOURNAL OF APPLIED ENTOMOLOGY, Issue 5 2010M. Meissle Abstract Political efforts are made in the European Union (EU) to reduce pesticide use and to increase the implementation of integrated pest management (IPM). Within the EU project ENDURE, research priorities on pesticide reduction are defined. Using maize, one of the most important crops in Europe, as a case study, we identified the most serious weeds, arthropod pests, and fungal diseases as well as classes and amounts of pesticides applied. Data for 11 European maize growing regions were collected from databases, publications and expert estimates. Silage maize dominates in northern Europe and grain production in central and southern Europe. Crop rotations range from continuous growing of maize over several years to well-planned rotation systems. Weeds, arthropod pests and fungal diseases cause economic losses in most regions, even though differences exist between northern countries and central and southern Europe. Several weed and arthropod species cause increasing problems, illustrating that the goal of reducing chemical pesticide applications is challenging. Pesticides could potentially be reduced by the choice of varieties including genetically modified hybrids, cultural control including crop rotation, biological control, optimized application techniques for chemicals, and the development of more specific treatments. However, restrictions in the availability of alternative pest control measures, farm organization, and the training and knowledge of farmers need to be overcome before the adoption of environmentally friendly pest control strategies can reduce chemical pesticides in an economically competitive way. The complex of several problems that need to be tackled simultaneously and the link between different control measures demonstrates the need for IPM approaches, where pest control is seen in the context of the cropping system and on a regional scale. Multicriteria assessments and decision support systems combined with pest monitoring programs may help to develop region-specific and sustainable strategies that are harmonized within a EU framework. [source] ASSESSMENT OF PREFERENCE WITH CONTROLS FOR RESPONSE BIAS OPERATING IN THE TEST SITUATION: A PRACTICAL EXAMPLE USING OMEGA-3 ENRICHED WHOLEGRAIN BREADS WITH ECUADORIAN CONSUMERSJOURNAL OF SENSORY STUDIES, Issue 5 2010YAMILLA ALVAREZ-COUREAUX ABSTRACT Ecuadorian consumers performed paired preference tests between sunflower rye bread and artisan wholegrain bread enriched with omega-3 fatty acids. Preferences for each were split fairly evenly. Further difference tests suggested that these preferences were elicited by visual rather than flavor/texture cues. The preference test included a "placebo" pair of "identical" stimuli to assess statistically whether the responses to the two test stimuli were merely because of response biases operating in the test situation and not differences in their sensory attributes. The concept of an "operational preference" was introduced to understand some of the ambiguities involved in the definition of preference. PRACTICAL APPLICATIONS The measurement of preference and acceptance of foods is important for product development and decisions regarding the launching of new products on to the market. The paired preference test has several problems associated with its design and analysis, and these are worthy of investigation. This article uses a practical example to illustrate some procedures developed as solutions to these challenges. Solutions to the problems involved in preference testing are essential so that the food industry can obtain trustworthy data. [source] Anterior sciatic nerve block , new landmarks and clinical experienceACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2005M. Wiegel Background: Anterior sciatic nerve blocks can be complicated by several problems. Pain can be caused by bony contacts and, in obese patients, identification of the landmarks is frequently difficult. Methods: In a first step, 100 normal anterior-posterior pelvic X-rays were analyzed. The landmarks of the classical anterior approach were drawn on these X-rays and assessed for their sufficiency. Then, in a prospective case study, 200 consecutive patients undergoing total knee replacement were investigated. These patients received femoral and sciatic nerve catheters for postoperative pain management. Using modified anatomical landmarks, sciatic nerve catheters were inserted 5 cm distal from the insertion site of the femoral nerve block perpendicularly in the midline of the lower extremity. This midline connected the insertion site of the femoral nerve catheter to the midpoint between the medial and lateral epicondyle. Correct catheter positioning was verified by magnetic resonance imaging (MRI) in six patients. Results: Evaluation of pelvic X-rays showed that puncture following the classical landmarks pointed in 51% at the lesser trochanter, in 5% medial to the lesser trochanter and in 42% directly at the femur. In the latter patients, location of the sciatic nerve would have been difficult or even impossible. Using our modified anterior approach, the sciatic nerve could be blocked in 196 patients (98%). In nine patients (4.5%) blockade of the posterior femoral cutaneous nerve failed. Vascular puncture happened in 10 (5%) and bony contact in 35 patients (17.5%). Median puncturing depth was 9.5 (7.5,14) cm. Correct sciatic nerve catheter positioning was verified in all patients who underwent MRI. Conclusion: Our landmarks for locating the sciatic nerve help to avoid bony contacts and thereby reduce pain during puncture. Our method reliably enabled catheter placement. [source] Antifungal susceptibility testing by flow cytometry: is it the future?MYCOSES, Issue 4 2006Luís André Vale-Silva Summary The current increase in the number and significance of fungal infections, the expanding armamentarium of antifungal agents, and the emergence of the problem of antifungal drug resistance have been intensifying the importance of antifungal susceptibility testing (AST). The Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) in the United States and the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST) published standard methodologies in order to achieve higher reproducibility and allow direct inter-laboratory comparison of the susceptibility results. Nevertheless, several problems remain unresolved and the methods depend on long incubation periods of a minimum of 24 h (EUCAST) or even 48 h (CLSI). Over the last 15 years, successful applications of flow cytometric techniques to AST of both yeast and moulds have been reported. These techniques are based on the analysis of a great number of fungal cells individually and frequently rely on short incubation times of no more than a few hours. Considering these attributes, flow cytometry (FC) seems to have the potential to achieve clinical usefulness in the near future. The collection of data on the reproducibility of the results and on the correlation with clinical outcomes has barely started, however. Practical validation of the experimental methodologies is not granted before a significant amount of data addressing those questions is available. [source] Nation on the move: the construction of cultural identities in Puerto Rico and the diasporaAMERICAN ETHNOLOGIST, Issue 1 2000Jorge Duany In this article, I analyze recent intellectual debates on the Puerto Rican nation and its persistent colonial relation with the United States. First, I trace the development of a nationalist discourse on the Island, primarily among intellectuals, writers, and artists during the 20th century. I identify several problems with this discourse, especially the exclusion of ethnic and racial others from its definition of the nation. Then I argue that any serious reconceptualization of Puerto Rican identity must include the diaspora in the United States. I focus on the increasingly bilateral flow of people between the Island and the U.S. mainland,what has come to be known as circular, commuter, or revolving door migration. The Spanish folk term for this back-and-forth movement is extremely suggestive: el vaiveYi (literally meaning fluctuation). La nacion en vaiven, the nation on the move, might serve as an apt metaphor for the fluid and hybrid identities of Puerto Ricans on both sides of the Atlantic. My thesis is that massive migration,both to and from the Island,has undermined conventional definitions of the nation based exclusively on territorial, linguistic, or juridical criteria, [cultural identity, diaspora, nationalism, transnationalism, circular migration, Puerto Ricans] [source] ,Dead-in-bed' syndrome , a diabetes nightmarePEDIATRIC DIABETES, Issue 5 2008Dror Koltin Abstract:, We report in this study the death in bed of a 14-yr-old girl with type 1 diabetes and a review of the existing literature on this topic. Diagnosed at 5 yr of age, the patient followed a relatively benign disease course. Hemoglobin A1c was 6.6,8.4%, and there were no hospital admissions apart from the one at diagnosis. Hypoglycemic episodes were not excessive or severe. At age 14 yr, the patient was found dead in bed after having been well the night before. No apparent explanation could be provided. The ,dead-in-bed' syndrome accounts for 5,6% of mortality cases in patients with type 1 diabetes, amounting to two to six cases per 10 000 patient years. Theories attempting to explain the mechanism for this syndrome include hypoglycemia or cardiac autonomic dysfunction. This case emphasizes several problems faced by clinicians: the risk for sudden death in youth with diabetes, which may compromise good glycemic control, the question of early detection of autonomic dysfunction, and the need to understand this phenomenon better and search for preventive measures. [source] Intensive insulin treatment in coronary and intensive carePRACTICAL DIABETES INTERNATIONAL (INCORPORATING CARDIABETES), Issue 1 2007Dr C Jones MRCP, MB ChB Specialist Registrar Abstract Hyperglycaemia in the setting of acute illness carries a poor prognosis. The first Diabetes and Insulin-Glucose infusion in Acute Myocardial Infarction (DIGAMI) study demonstrated a reduction in total mortality with intravenous insulin to reduce hyperglycaemia followed by multi-dose subcutaneous insulin in diabetic patients following myocardial infarction. Unfortunately, there were several problems with the follow-up DIGAMI-2 study, so that it is not clear if maximum benefit was obtained by intravenous insulin, subcutaneous insulin, or a combination of both. In the surgical intensive care unit (ICU) setting, intensive insulin to restore normoglycaemia reduced total mortality in patients admitted to a surgical ICU who developed hyperglycaemia. In a follow-up study in medical ICU patients the results were disappointing, and there was no overall reduction in mortality. There is a need for a study which would combine these two complementary approaches, examining the possible benefits of using very intensive insulin treatment to achieve normoglycaemia following myocardial infarction in patients with diabetes. Copyright © 2007 John Wiley & Sons. [source] Flores hominid: New species or microcephalic dwarf?THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 11 2006Robert D. Martin Abstract The proposed new hominid "Homo floresiensis" is based on specimens from cave deposits on the Indonesian island Flores. The primary evidence, dated at , 18,000 y, is a skull and partial skeleton of a very small but dentally adult individual (LB1). Incomplete specimens are attributed to eight additional individuals. Stone tools at the site are also attributed to H. floresiensis. The discoverers interpreted H. floresiensis as an insular dwarf derived from Homo erectus, but others see LB1 as a small-bodied microcephalic Homo sapiens. Study of virtual endocasts, including LB1 and a European microcephalic, purportedly excluded microcephaly, but reconsideration reveals several problems. The cranial capacity of LB1 (, 400 cc) is smaller than in any other known hominid < 3.5 Ma and is far too small to derive from Homo erectus by normal dwarfing. By contrast, some associated tools were generated with a prepared-core technique previously unknown for H. erectus, including bladelets otherwise associated exclusively with H. sapiens. The single European microcephalic skull used in comparing virtual endocasts was particularly unsuitable. The specimen was a cast, not the original skull (traced to Stuttgart), from a 10-year-old child with massive pathology. Moreover, the calotte does not fit well with the rest of the cast, probably being a later addition of unknown history. Consideration of various forms of human microcephaly and of two adult specimens indicates that LB1 could well be a microcephalic Homo sapiens. This is the most likely explanation for the incongruous association of a small-brained recent hominid with advanced stone tools. Anat Rec Part A, 288A:1123,1145, 2006. © 2006 Wiley-Liss, Inc. [source] Structured additive regression for overdispersed and zero-inflated count dataAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 4 2006Ludwig Fahrmeir Abstract In count data regression there can be several problems that prevent the use of the standard Poisson log-linear model: overdispersion, caused by unobserved heterogeneity or correlation, excess of zeros, non-linear effects of continuous covariates or of time scales, and spatial effects. We develop Bayesian count data models that can deal with these issues simultaneously and within a unified inferential approach. Models for overdispersed or zero-inflated data are combined with semiparametrically structured additive predictors, resulting in a rich class of count data regression models. Inference is fully Bayesian and is carried out by computationally efficient MCMC techniques. Simulation studies investigate performance, in particular how well different model components can be identified. Applications to patent data and to data from a car insurance illustrate the potential and, to some extent, limitations of our approach. Copyright © 2006 John Wiley & Sons, Ltd. [source] Introductory course based on a single problem: Learning nucleic acid biochemistry from AIDS researchBIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION, Issue 6 2004Neena Grover Abstract In departure from the standard approach of using several problems to cover specific topics in a class, I use a single problem to cover the contents of the entire semester-equivalent biochemistry classes. I have developed a problem-based service-learning (PBSL) problem on HIV/AIDS to cover nucleic acid concepts that are typically taught in the second semester of a biochemistry class. Use of research articles on a specific topic allows developing problems such as one discussed here. The implementation of this problem is similar to teaching literature-based courses but is tailored to undergraduate work. Details of designing and setting up this problem, along with the pros and cons of this approach, are discussed here. [source] Human immature dental pulp stem cells share key characteristic features with limbal stem cellsCELL PROLIFERATION, Issue 5 2009B. G. Monteiro Objectives:, Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. Materials:, We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. Results and conclusions:, We have demonstrated, using immunohistochemistry and reverse transcription,polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin ,1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction. [source] Amino Acid Ligand Chirality for Enantioselective SynthesesCHEMISTRY & BIODIVERSITY, Issue 6 2010Károly Micskei Abstract Amino acids are attractive sources of chirality in stoichiometric or catalytic transition metal/organic chemistry. In spite of easy availability and other advantages, the application of these ligands is hindered by several problems. Now, at the dawn of emerging d- amino acid biochemistry, efforts in this direction are becoming increasingly important. The results of research on application of amino acid ligands for transition-metal reagents in organic syntheses are reviewed in the present work. [source] Action Mechanism of Insulin-Mimetic Vanadyl,Allixin ComplexCHEMISTRY & BIODIVERSITY, Issue 8 2008Makoto Hiromura Abstract In the 21st century, there has been a dramatic worldwide increase in the prevalence of metabolic syndromes, including diabetes mellitus (DM). Several synthetic pharmaceutical agents have been developed and used for the treatment of type-2 DM; however, these compounds have several problems such as side effects, hypoglycemia, and weight gain. Therefore, new drugs are required for DM therapy. We have proposed that some vanadyl complexes function as potent insulin-mimetic and antidiabetic agents in type-1 and type-2 DM animal models. In this article, we review the possible action mechanism of insulin-mimetic and antidiabetic vanadyl complexes, focusing on a recently proposed complex, bis(allixinato)oxovanadium(IV), with respect to the insulin-signaling pathway in cultured adipocytes. [source] | |||||||||||||||||||||||||