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Dynamic Changes (dynamic + change)
Selected AbstractsContinuous Intraoperative Transesophageal Echocardiography during Pericardiectomy for Constrictive Pericarditis Revealing Dynamic Change in Chamber SizeECHOCARDIOGRAPHY, Issue 5 2005Babak Kasravi M.D. We review a case of a 50-year-old man with diagnosis of constrictive pericarditis, who underwent pericardial stripping with continuous intraoperative transesophageal echocardiography (TEE). This patient demonstrates the immediate dynamic changes in chamber size after successful surgical removal of pericardium as demonstrated by TEE. [source] Empathy Is Associated With Dynamic Change in Prefrontal Brain Electrical Activity During Positive Emotion in ChildrenCHILD DEVELOPMENT, Issue 4 2009Sharee N. Light Empathy is the combined ability to interpret the emotional states of others and experience resultant, related emotions. The relation between prefrontal electroencephalographic asymmetry and emotion in children is well known. The association between positive emotion (assessed via parent report), empathy (measured via observation), and second-by-second brain electrical activity (recorded during a pleasurable task) was investigated using a sample of one hundred twenty-eight 6- to 10-year-old children. Contentment related to increasing left frontopolar activation (p < .05). Empathic concern and positive empathy related to increasing right frontopolar activation (ps < .05). A second form of positive empathy related to increasing left dorsolateral activation (p < .05). This suggests that positive affect and (negative and positive) empathy both relate to changes in prefrontal activity during a pleasurable task. [source] Dynamic Changes of Ictal High-Frequency Oscillations in Neocortical Epilepsy: Using Multiple Band Frequency AnalysisEPILEPSIA, Issue 2 2007Ayako Ochi Summary:,Purpose: To characterize the spatial and temporal course of ictal high-frequency oscillations (HFOs) recorded by subdural EEG in children with intractable neocortical epilepsy. Methods: We retrospectively studied nine children (four girls, five boys; 4,17 yr) who presented with intractable extrahippocampal localization-related epilepsy and who underwent extraoperative video subdural EEG (1000 Hz sampling rate) and cortical resection. We performed multiple band frequency analysis (MBFA) to evaluate the frequency, time course, and distribution of ictal HFOs. We compared ictal HFO changes before and after clinical onset and postsurgical seizure outcomes. Results: Seventy-eight of 79 seizures showed HFOs. We observed wide-band HFOs (,250Hz, ,120 electrodes) in six patients either with partial seizures alone (three patients) or with epileptic spasms (three patients). Three patients with partial seizures that secondarily generalized had wide-band HFOs (,170 Hz) before clinical onset and sustained narrow-band HFOs (60,164 Hz) with electrodecremental events after clinical onset (,28 electrodes). In four postoperatively seizure-free patients, more electrodes recorded higher-frequency HFOs inside the resection area than outside before and after clinical seizure onset. In five patients with residual seizures, electrodes recorded more HFOs that were of higher or equal frequency outside the surgical area than inside after clinical onset. Conclusion: For partial seizures alone and epileptic spasms, more electrodes recorded only wide-band HFOs; for partial seizures that secondarily generalized, fewer electrodes recorded wide-band HFOs, but in these seizures electrodes also recorded subsequent sustained narrow-band ictal HFOs. Resection of those brain regions having electrodes with ictal, higher HFOs resulted in postsurgical seizure-free outcomes. [source] Dynamic Changes of T-Wave Alternans: Does It Predict Short-Term Arrhythmia Vulnerability?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2007S. LUKE KUSMIREK M.D. [source] Behavior of Nonselective Cation Channels and Large-Conductance Ca2+ -Activated K+ Channels Induced by Dynamic Changes in Membrane Stretch in Cultured Smooth Muscle Cells of Human Coronary ArteryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2003PH.D., SHENG-NAN WU M.D. Stretch-Activated Ion Channels. Introduction: The effects of membrane stretch on ion channels were investigated in cultured smooth muscle cells of human coronary artery. Methods and Results: In the cell-attached configuration, membrane stretch with negative pressure induced two types of stretch-activated (SA) ion channels: a nonselective cation channel and a large-conductance Ca2+ -activated K+ (BKCa) channel. The single-channel conductances of SA cation and BKCa channels were 26 and 203 pS, respectively. To elucidate the mechanism of activation of these SA channels and to minimize mechanical disruption, a sinusoidal change in pipette pressure was applied to the on-cell membrane patch. During dynamic changes in pipette pressure, increases in SA cation channel activity was found to coincide with increases in BKCa channel activity. In the continued presence of cyclic stretch, the activity of SA cation channels gradually diminished. However, after termination of cyclic stretch, BKCa channel activity was greatly enhanced, but the activity of SA cation channels disappeared. Conclusion: This study is the first to demonstrate that the behavior of SA cation and BKCa channels in coronary smooth muscle cells is differentially susceptible to dynamic changes in membrane tension. [source] Dynamic Changes in Lymphocyte GRK2 Levels in Cardiac Transplant Patients: A Biomarker for Left Ventricular FunctionCLINICAL AND TRANSLATIONAL SCIENCE, Issue 1 2010Raphael E. Bonita M.D., Sc.M. Abstract G protein-coupled receptor kinase 2 (GRK2), which is upregulated in the failing human myocardium, appears to have a role in heart failure (HF) pathogenesis. In peripheral lymphocytes, GRK2 expression has been shown to reflect myocardial levels. This study represents an attempt to define the role for GRK2 as a potential biomarker of left ventricular function in HF patients. We obtained blood from 24 HF patients before and after heart transplantation and followed them for up to 1 year, also recording hemodynamic data and histological results from endomyocardial biopsies. We determined blood GRK2 protein by Western blotting and enzyme-linked immunosorbent assay. GRK2 levels were obtained before transplant and at first posttransplant biopsy. GRK2 levels significantly declined after transplant and remained low over the course of the study period. After transplantation, we found that blood GRK2 signifi cantly dropped and remained low consistent with improved cardiac function in the transplanted heart. Blood GRK2 has potential as a biomarker for myocardial function in end-stage HF. Clin Trans Sci 2010; Volume #: 1,5 [source] Process control and monitoring of reactive crystallization of L -glutamic acidAICHE JOURNAL, Issue 8 2010Hannu Alatalo Abstract The aim of the present study was to investigate feedback control of a reactive crystallization process. The present study built up a control structure needed to control the driving force of reactive crystallization using the feed rate of added acid. The concentration of the crystallizing compound and pH was used to compute feedback in the closed-loop control of semi-batch precipitation. The concentration of L -glutamic acid was determined from measured MID-IR ATR-FTIR spectra based on a multivariate model. Dynamic change of set value was based on the mass of added sulfuric acid and pH. The studied properties of the product crystals were polymorphism and crystal size. The polymorphic composition was analyzed with a Raman spectrometer and was expressed by mass fraction of the ,-polymorph. The obtained results showed that the developed feedback process control system allows effective control of forming of polymorphs. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Dynamic change of corporate environmental strategy: rhetoric and realityBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 3 2003Professor Seung-Kyu Rhee Although rhetoric involves political and symbolic posture, and does not always accurately represent reality, it plays an important role in the dynamic change process of environmental strategy. We first elaborate on the related concepts and develop frameworks to analyze corporate environmental strategy and its change. We report two case studies of Korean companies using the framework. Longitudinal case studies also provide additional implications for corporate environmental strategy in developing countries such as Korea. There is a gap between the rhetoric and reality of environmental strategy and it constantly changes over time depending on specific internal and external influences. The strength of external influences is a factor that determines whether the change is real or merely rhetorical. Internal organizational variables most likely affect the reality of environmental strategy. We show that the elaboration of rhetorical and realistic aspects of corporate environmentalism can bring out deeper insights and new theoretical developments. Copyright © 2003 John Wiley & Sons, Ltd. and ERP Environment [source] Local Housing Markets and Segregation in EnglandECONOMIC OUTLOOK, Issue 1 2005Article first published online: 2 FEB 200 In this article, Geoff Meen discusses patterns of economic segregation in England. Despite the emphasis that the government places on reducing segregation, patterns have, in fact, remained remarkably constant over, at least, the last twenty years. Dynamic changes in housing markets and migration over time help to explain these patterns, and evidence is presented on the extent to which house prices in certain local authorities have been under- or over-valued. The analysis also shows that, at the local level, housing markets exhibit non-linear behaviour, which hinders the effectiveness of housing policy in the most deprived areas and adds to economic segregation. [source] Dynamic changes in glypican-1 expression in dorsal root ganglion neurons after peripheral and central axonal injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2004Stefan Bloechlinger Abstract Glypican-1, a glycosyl phosphatidyl inositol (GPI)-anchored heparan sulphate proteoglycan expressed in the developing and mature cells of the central nervous system, acts as a coreceptor for diverse ligands, including slit axonal guidance proteins, fibroblast growth factors and laminin. We have examined its expression in primary sensory dorsal root ganglion (DRG) neurons and spinal cord after axonal injury. In noninjured rats, glypican-1 mRNA and protein are constitutively expressed at low levels in lumbar DRGs. Sciatic nerve transection results in a two-fold increase in mRNA and protein expression. High glypican-1 expression persists until the injured axons reinnervate their peripheral targets, as in the case of a crushed nerve. Injury to the central axons of DRG neurons by either a dorsal column injury or a dorsal root transection also up-regulates glypican-1, a feature that differs from most DRG axonal injury-induced genes, whose regulation changes only after peripheral and not central axonal injury. After axonal injury, the cellular localization of glypican-1 changes from a nuclear pattern restricted to neurons in noninjured DRGs, to the cytoplasm and membrane of injured neurons, as well as neighbouring non-neuronal cells. Sciatic nerve transection also leads to an accumulation of glypican-1 in the proximal nerve segment of injured axons. Glypican-1 is coexpressed with robo 2 and its up-regulation after axonal injury may contribute to an altered sensitivity to axonal growth or guidance cues. [source] Dynamic changes in the epigenomic state and nuclear organization of differentiating mouse embryonic stem cellsGENES TO CELLS, Issue 4 2007Satoru Kobayakawa Changes in nuclear organization and the epigenetic state of the genome are important driving forces for developmental gene expression. However, a strategy that allows simultaneous visualization of the dynamics of the epigenomic state and nuclear structure has been lacking to date. We established an experimental system to observe global DNA methylation in living mouse embryonic stem (ES) cells. The methylated DNA binding domain (MBD) and the nuclear localization signal (nls) sequence coding for human methyl CpG-binding domain protein 1 (MBD1) were fused to the enhanced green fluorescent protein (EGFP) reporter gene, and ES cell lines carrying the construct (EGFP-MBD-nls) were established. The EGFP-MBD-nls protein was used to follow DNA methylation in situ under physiological conditions. We also monitored the formation and rearrangement of methylated heterochromatin using EGFP-MBD-nls. Pluripotent mouse ES cells showed unique nuclear organization in that methylated centromeric heterochromatin coalesced to form large clusters around the nucleoli. Upon differentiation, the organization of these heterochromatin clusters changed dramatically. Time-lapse microscopy successfully captured a moment of dramatic change in chromosome positioning during the transition between two differentiation stages. Thus, this experimental system should facilitate studies focusing on relationships between nuclear organization, epigenetic status and cell differentiation. [source] Dynamic changes in the direction of the theta rhythmic drive between supramammillary nucleus and the septohippocampal systemHIPPOCAMPUS, Issue 6 2006Bernat Kocsis Abstract Neurons in the supramammillary nucleus (SUM) of urethane-anesthetized rats fire rhythmically in synchrony with hippocampal theta rhythm. As these neurons project to the septum and hippocampus, it is generally assumed that their role is to mediate ascending activation, leading to the hippocampal theta rhythm. However, the connections between SUM and the septohippocampal system are reciprocal; there is strong evidence that theta remains in the hippocampus after SUM lesions and in the SUM after lesioning the medial septum. The present study examines the dynamics of coupling between rhythmic discharge in the SUM and hippocampal field potential oscillations, using the directionality information carried by the two signals. Using directed transfer function analysis, we demonstrate that during sensory-elicited theta rhythm and also during short episodes of theta acceleration of spontaneous oscillations, the spike train of a subpopulation of SUM neurons contains information predicting future variations in rhythmic field potentials in the hippocampus. In contrast, during slow spontaneous theta rhythm, it is the SUM spike signal that can be predicted from the preceding segment of the electrical signal recorded in the hippocampus. These findings indicate that, in the anesthetized rat, SUM neurons effectively drive theta oscillations in the hippocampus during epochs of sensory-elicited theta rhythm and short episodes of theta acceleration, whereas spontaneous slow theta in the SUM is controlled by descending input from the septohippocampal system. Thus, in certain states, rhythmically firing SUM neurons function to accelerate the septal theta oscillator, and in others, they are entrained by a superordinate oscillatory network. © 2006 Wiley-Liss Inc. [source] Dynamic changes in nerve growth factor and substance P in the murine hair cycle induced by depilationTHE JOURNAL OF DERMATOLOGY, Issue 12 2006Zhanchao ZHOU ABSTRACT Increasing evidence suggests that various neurotrophins and neuropeptides play an important role in the progression of hair follicle cycling. Among them, nerve growth factor (NGF) and substance P (SP) have attracted special interest recently. However, the interaction between these factors during hair cycling has not yet been systematically studied. We therefore investigated the mutual relationships between NGF and SP and the mechanism by which the anagen stage of the hair cycle is initiated. Fluctuations in numbers of SP-positive nerve fibers and variations in amounts of SP, NGF, and another neurotrophic factor, glial cell-derived neurotrophic factor, in skin in the C57BL/6 mouse depilation-induced hair cycle model, together with the spatiotemporal expression patterns of each of these factors, were followed simultaneously by enzyme-linked immunosorbent assay and immunohistochemistry. The main finding was that a surge in NGF expression and a rapid increase in NGF content in skin is an initial event within 1 day after depilation, followed by elevation of SP content and numbers of SP-containing fibers 2 days after the increase in NGF. Our findings suggest that a rapid and abundant increase in NGF plays a key role in the induction and progression of anagen hair cycling through keratinocyte growth promotion. NGF may also induce plastic changes such as sprouting and hyperplasia in dermal nerve fibers and enhance their SP production. Elevated levels of SP in skin may additionally contribute to the progression of consecutive anagen hair cycles. [source] Dynamic changes in gene expression during vitellogenic stages of the white shrimp: Fenneropenaeus merguiensis de ManAQUACULTURE RESEARCH, Issue 6 2009Monwadee Wonglapsuwan Abstract Ovarian maturation is a crucial step for shrimp brood stock. A suppressive subtractive hybridization was used to identify differentially expressed genes in the ovaries during vitellogenesis of Fenneropenaeus merguiensis. Three- to sevenfold up-regulated genes were selected. A blast search identified nine unique genes. The genes that may be involved in ovarian maturation, namely translationally controlled tumour protein (TCTP), heat shock protein 70 (HSP70), H-L(3)MBT-LIKE, shrimp ovarian peritrophin (SOP), vitellin (Vn), thrombospondin (TSP) and ribosomal protein L10a (RPL10a), were further studied. The transcripts of HSP70, TCTP, SOP and RPL10a in the ovary showed their highest expression in the early stage and declined in the later stages. In contrast, the transcripts of the H-L(3)MBT-LIKE, TSP and Vn genes increased from the early stage to be significantly up-regulated during the late stage. A comparison of gene expression among organs during the vitellogenesis showed that the transcripts of HSP70, SOP, H-L(3)MBT-LIKE and TSP were down-regulated in the brain, intestine, hepatopancreas and lymphoid (except for TSP) when compared with their expression in shrimp with non-developed ovaries. The mRNA of TCTP and RPL10a was significantly over-expressed in the lymphoid and heart, whereas TCTP transcripts were significantly down-regulated in the brain during the vitellogenesis. The molecular behaviour of the transcripts in this study may, in the future, lead to an ability to stimulate the ovarian development in shrimp. [source] Dynamic changes in CD4+ CD25+ high T cell apoptosis after the diagnosis of type 1 diabetesCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2007S. Glisic-Milosavljevic Summary Because type 1 diabetes (T1D) is a chronic, autoimmune, T cell-mediated disease, interventions affecting T cells are expected to modulate the immune cascade and lead to disease remission. We propose that increased CD4+ CD25+high T cell apoptosis, a trait we discovered in recent-onset T1D subjects, reflects T1D partial remission within the first 6 months after diagnosis. Apoptosis of forkhead box P3 (FoxP3)+ CD4+ CD25+high T cells, in addition to total daily doses of insulin (TDD), blood glucose, HbA1c and age, were measured in 45 subjects with T1D at various times after diagnosis. Sixteen healthy control subjects were also recruited to the study. Higher CD4+ CD25+high T cell apoptosis levels were detected within the first 6 months of diagnosis (odds ratio = 1·39, P = 0·009), after adjustment for age, TDD and HbA1c. A proportional hazards model confirmed that the decline of apoptosis after diagnosis of T1D was related significantly to survival time (hazards ratio = 1·08, P = 0·014), with TDD and age also contributing to survival. During this time there was an inverse relationship between CD4+ CD25+high T cell apoptosis with TDD (r = ,0·39, P = 0·008). The CD4+ CD25+high T cell apoptosis levels decline significantly after the first 6 months from diagnosis of T1D and may help in the close monitoring of autoimmunity. In parallel, there is an increase in TDD during this time. We also propose that CD4+ CD25+high T cell apoptosis assay can be used to gauge the efficacy of the several immune tolerance induction protocols, now under way. [source] Dynamic wavefront aberrations and visual acuity in normal and dry eyesCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2009Yan Wang MD Purpose:, The aim was to study the dynamic properties of wavefront aberrations and visual acuity in normal and dry eyes. Methods:, Thirty dry-eye patients and 27 normal subjects participated in this study. Multi-file mode of a Hartmann-Shack wavefront sensor was used to measure dynamic wavefront aberrations for a period of 45 seconds. Dynamic measurements of visual acuity (VA) were made for 150 seconds using a multi-functional VA tester. Standard deviation of the measurements (RMS or VA) over the testing period was used to estimate instability of the dynamic wavefront aberration and VA. Results:, For most subjects, both wavefront aberration and VA changed over time and the instability varied substantially among individuals. Blink-dependent fluctuation in wavefront aberration or VA was observed for some dry-eye subjects. On average, the dry-eye group had greater instability than the normal group in either the higher order wavefront aberrations (t = 2.09, p = 0.03, for OD; t = 3.76, p = 0.001, for OS) or the VA (t = 2.09, p = 0.02, for OD; t = 204, p = 0.03, for OS). Instability of VA in the dry-eye group was significantly correlated with blink rate (r = 0.28, p = 0.02). Conclusion:, Dynamic changes in wavefront aberrations and VA are highly individual dependent, while the dry eye tends to be less stable than the normal eye. The results suggest that tear-film fluctuation might play a role in determining dynamic wavefront aberration and VA, however, contributions from other factors should not be overlooked. For dry eye, dynamic change in VA depends on blink rate. [source] Proximity to the US,Mexico border: a key to explaining geographic variation in US methamphetamine, cocaine and heroin purityADDICTION, Issue 10 2010James K. Cunningham ABSTRACT Aims Although illicit drug purity is a widely discussed health risk, research explaining its geographic variation within a country is rare. This study examines whether proximity to the US,Mexico border, the United States' primary drug import portal, is associated with geographic variation in US methamphetamine, heroin and cocaine purity. Design Distances (proximity) between the US,Mexico border and locations of methamphetamine, cocaine and heroin seizures/acquisitions (n = 239 070) recorded in STRIDE (System to Retrieve Information from Drug Evidence) were calculated for the period of 1990,2004. The association of drug purity with these distances and other variables, including time and seizure/acquisition size, was examined using hierarchical multivariate linear modeling (HMLM). Setting Coterminous United States. Findings Methamphetamine, cocaine and heroin purity generally decreased with distance from the US,Mexico border. Heroin purity, however, after initially declining with distance, turned upwards,a U-shaped association. During 2000,04, methamphetamine purity also had a U-shaped association with distance. For each of the three drugs, temporal changes in the purity of small acquisitions (<10 g) were typically more dynamic in areas closer to the US,Mexico border. Conclusions Geographic variance in methamphetamine, cocaine and heroin purity throughout the coterminous United States was associated with US,Mexico border proximity. The U-shaped associations between border-distance and purity for heroin and methamphetamine may be due to imports of those drugs via the eastern United States and southeast Canada, respectively. That said, areas closer to the US,Mexico border generally had relatively high illicit drug purity, as well as more dynamic change in the purity of small (,retail level') drug amounts. [source] Effect of temperature change on the composition of the bacterial and archaeal community potentially involved in the turnover of acetate and propionate in methanogenic rice field soilFEMS MICROBIOLOGY ECOLOGY, Issue 2 2010Matthias Noll Abstract The microbial community structure was investigated together with the path of methane production in Italian rice field soil incubated at moderate (35 °C) and high (45 °C) temperature using terminal restriction fragment length polymorphism and stable isotope fractionation. The structure of both the archaeal and bacterial communities differed at 35 °C compared with 45 °C, and acetoclastic and hydrogenotrophic methanogenesis dominated, respectively. Changing the incubation of the 45 °C soil to different temperatures (25, 30, 35, 40, 45, 50 °C) resulted in a dynamic change of both microbial community structure and stable isotope fractionation. In all treatments, acetate first accumulated and then decreased. Propionate was also transiently produced and consumed. It is noteworthy that acetate was also consumed at thermophilic conditions, although archaeal community composition and stable isotope fractionation indicated that acetoclastic methanogenesis did not operate. Instead, acetate must have been consumed by syntrophic acetate oxidizers. The transient accumulation and subsequent consumption of acetate at thermophilic conditions was specifically paralleled by terminal restriction fragments characteristic for clostridial cluster I, whereas those of clostridial clusters I and III, Acidaminococcaceae and Heliobacteraceae, paralleled the thermophilic turnover of both acetate and propionate. [source] Modelling the hydrologic effects of dynamic land-use change using a distributed hydrologic model and a spatial land-use allocation modelHYDROLOGICAL PROCESSES, Issue 18 2010Hone-Jay Chu Abstract This study develops a novel approach for modelling and examining the impacts of time,space land-use changes on hydrological components. The approach uses an empirical land-use change allocation model (CLUE-s) and a distributed hydrological model (DHSVM) to examine various land-use change scenarios in the Wu-Tu watershed in northern Taiwan. The study also uses a generalized likelihood uncertainty estimation approach to quantify the parameter uncertainty of the distributed hydrological model. The results indicate that various land-use policies,such as no change, dynamic change and simultaneous change,have different levels of impact on simulating the spatial distributions of hydrological components in the watershed study. Peak flow rates under simultaneous and dynamic land-use changes are 5·71% and 2·77%, respectively, greater than the rate under the no land-use change scenario. Using dynamic land-use changes to assess the effect of land-use changes on hydrological components is more practical and feasible than using simultaneous land-use change and no land-use change scenarios. Furthermore, land-use change is a spatial dynamic process that can lead to significant changes in the distributions of ground water and soil moisture. The spatial distributions of land-use changes influence hydrological processes, such as the ground water level of whole areas, particularly in the downstream watershed. Copyright © 2010 John Wiley & Sons, Ltd. [source] Negative regulation of endogenous protein kinase C, on the dynamic change of carbachol-induced intracellular calcium response in different melanoma cells,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2009Huan Wang Regulations of intracellular protein kinase C (PKC) on carbachol (CCh)-induced intracellular calcium ([Ca2+]i) responses were investigated in different stages of melanoma cells. We found that CCh (1,mM) significantly increased [Ca2+]i with 6-, 4-, 4-, and 25-folds intensities in WM793B, 451Lu, SK-MEL-5, and A2058 melanoma cells, respectively. Pretreatment of phorbol 12, 13-dibutyrate (PDBu, 2,µM), an activator of intracellular PKC, significantly suppressed CCh-induced peak reactions in WM793B, SK-MEL-5, and A2058 cells. RT-PCR data showed that mRNA levels of PKC, were 12-, 4-, 6-, and 0.9-folds higher in above four melanoma cells. Short interfering RNA (siRNA) targeting to PKC, in WM793B cells enhanced CCh-induced peak calcium reactions. Present data indicated that CCh-induced [Ca2+]i responses were dynamically changed in different stages of melanoma progression. Moreover, intracellular PKC, activated by exogenous agonist and expressed through endogenous gene transcription negatively regulated CCh-induced calcium responses. The functional analysis on the relationship between CCh-induced calcium response and endogenous PKC, expression might be helpful to predict the development of melanoma. J. Cell. Physiol. 221: 276,282, 2009. © 2009 Wiley-Liss, Inc. [source] Theorizing TQM: An Austrian and Evolutionary Economics InterpretationJOURNAL OF MANAGEMENT STUDIES, Issue 2 2000Todd H. Chiles Born out of management practice, the principles of TQM (total quality management) have had a profound and unparalleled impact on modern business history. However, as a body of practical knowledge, TQM has been largely atheoretical. As a consequence, this important management philosophy has remained amorphous and shrouded in considerable conceptual haziness and ambiguity. Recent theorizing, primarily emphasizing the application of organizational behaviour theories to TQM, has begun to provide greater clarity, but much work remains to be done. This paper attempts to contribute to this nascent theory-building literature by employing theory from market process economics (MPE), namely, Austrian and evolutionary economics, which explains how processes of dynamic change, adaptation, and learning are driven by entrepreneurial creativity. We contend that the patterns in this body of theory match, to a remarkable degree, the patterns of practical knowledge contained in the TQM literature. We demonstrate this ,pattern-matching' by showing that MPE effectively provides the theoretical underpinnings of TQM's three main principles , customer focus, continuous improvement and teamwork , as well as the respective TQM topics of customer perceptions, adaptation in dynamic environments, and knowledge creation. Having established MPE as a credible theoretical lens for interpreting TQM, it can be used to clarify fuzzy areas that have remained in the TQM literature with the potential to take us beyond what we know now. We illustrate this with three examples that show how we can resolve debates in TQM over incentive systems, recognize that TQM embraces methodological pluralism in the collection and analysis of data, and highlight hidden dangers that attend benchmarking. While MPE has no monopoly on theoretical interpretations of TQM, it is unique in its ability to comprehensively cover the incredible breadth of this practical body of knowledge, and in its interpretation of TQM as a dynamic economic endeavour. [source] Sp proteins play a critical role in histone deacetylase inhibitor-mediated derepression of CYP46A1 gene transcriptionJOURNAL OF NEUROCHEMISTRY, Issue 2 2010Maria Joćo Nunes J. Neurochem. (2010) 113, 418,431. Abstract We investigated whether the CYP46A1 gene, a neuronal-specific cytochrome P450, responsible for the majority of brain cholesterol turnover, is subject to transcriptional modulation through modifications in histone acetylation. We demonstrated that inhibition of histone deacetylase activity by trichostatin A (TSA), valproic acid and sodium butyrate caused a potent induction of both CYP46A1 promoter activity and endogenous expression. Silencing of Sp transcription factors through specific small interfering RNAs, or impairing Sp binding to the proximal promoter, by site-directed mutagenesis, led to a significant decrease in TSA-mediated induction of CYP46A1 expression/promoter activity. Electrophoretic mobility shift assay, DNA affinity precipitation assays and chromatin immunoprecipitation assays were used to determine the multiprotein complex recruited to the CYP46A1 promoter, upon TSA treatment. Our data showed that a decrease in Sp3 binding at particular responsive elements, can shift the Sp1/Sp3/Sp4 ratio, and favor the detachment of histone deacetylase (HDAC) 1 and HDAC2 and the recruitment of p300/CBP. Moreover, we observed a dynamic change in the chromatin structure upon TSA treatment, characterized by an increase in the local recruitment of euchromatic markers and RNA polymerase II. Our results show the critical participation of an epigenetic program in the control of CYP46A1 gene transcription, and suggest that brain cholesterol catabolism may be affected upon treatment with HDAC inhibitors. [source] Differential expression of E-cadherin in metastatic lesionscomparing to primary oral squamous cell carcinomaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 10 2006K.-F. Hung Background:, The main cause of treatment failure in resectable oral squamous cell carcinoma (OSCC) is metastasis. E-cadherin (E-cad) plays a principal role in cell adhesion and motility, and is associated with OSCC progression. The aim of this study was to investigate the clinical significance of E-cad expression in OSCC with lymph node metastasis which had radical neck dissection done. Method:, Immunohistochemistry was used to detect E-cad expression in normal oral mucosa (NOM) (n = 10), oral precancerous lesions (OPLs) (n = 20), primary OSCC (n = 45), and their paired metastatic lesions (n = 45). E-cad immunoreactivity correlated with the clinicopathologic features. Results:, E-cadherin immunoreactivity was progressively reduced in the NOM followed by OPLs and primary OSCC (58%). It decreased significantly in the advanced stages of OSCC. However, the increase in E-cad immunoreactivity was observed in the majority (60%) of metastatic lesions in relation to primary OSCC. Patients with such increased or positive immunoreactivity of E-cad in metastatic lesions exhibited worse prognosis. Conclusion:, The findings suggested a dynamic change in E-cad immunoreactivity during tumorigenesis and metastasis of OSCC. In a multivariate analysis, E-cad immunoreactivity in metastasis lesions (odds ratio 3.74, 95% CI 1.15,14.67; P = 0.040) implied the potential role of mortality predictors for OSCC cases with nodal involvement. [source] Granulocyte elastase activity in static and flow gingival crevicular fluidJOURNAL OF PERIODONTAL RESEARCH, Issue 3 2003Lijian Jin Objectives:, This study aimed to evaluate the volume of gingival crevicular fluid (GCF) and granulocyte elastase activity in static GCF (sGCF) and flow GCF (fGCF) from subjects with various periodontal conditions. Methods:, Eleven periodontally healthy, 10 gingivitis and 12 periodontitis subjects were recruited and the sites investigated consisted of healthy sites from healthy subjects (HH); healthy (HG) and gingivitis sites (GG) from gingivitis subjects; and healthy (HP), gingivitis (GP) and periodontitis sites (PP) from periodontitis subjects. fGCF samples were collected either 1 min or 5 min following sGCF collection by paper strip technique. GCF volume was determined by Periotron® 6000 and granulocyte elastase activity was assayed with a specific substrate [l -pyroglutamyl- l -prolyl- l -valine- p -nitroanilide(pGluProVal-pNA)]. Results:, At baseline, no significant differences existed in clinical and GCF parameters between the two matched sites for subsequent collection of fGCF samples either 1 min or 5 min after sGCF sampling in all subjects. The flow exudate in HG and HP sites quickly replenished to sGCF levels, while a delayed replenishment was found in HH sites, despite the similar sGCF volumes of these sites. The GCF volume and elastase levels in the fGCF at 1 min were higher in GP sites than in GG sites (P < 0.05). Overall, depletion of elastase levels in the fGCF at 1 min was observed in all subjects, whereas elastase levels in the fGCF at 5 min had replenished to sGCF levels in HP, GP, PP sites and GG sites, but had remained at a lower level in HH and HG sites. An overall positive correlation was found between sGCF and fGCF for GCF volume and elastase activity (P < 0.001); however, this correlation varied with GCF parameters and with site conditions of the subjects concerned. Conclusions:, This study shows that patterns of dynamic changes in GCF flow and elastase activity varied under different periodontal conditions. Assessment of both sGCF and fGCF may allow better insight into the dynamic change of the target components in GCF. [source] x-f choice: Reconstruction of undersampled dynamic MRI by data-driven alias rejection applied to contrast-enhanced angiographyMAGNETIC RESONANCE IN MEDICINE, Issue 4 2006Shaihan J. Malik Abstract A technique for reconstructing dynamic undersampled MRI data, termed "x-f choice," was developed and applied to dynamic contrast-enhanced MR angiography (DCE-MRA). Regular undersampling in k-t space (a hybrid of k -space and time) creates aliasing in the conjugate x-f space that must be resolved. When regions in the object containing fast dynamic change are sparse, as in DCE-MRA, signal overlap caused by aliasing is often much less than the undersample factor would imply. x-f Choice reconstruction identifies overlapping signals using a model of the full non-aliased x-f space that is automatically generated from the undersampled data, and applies parallel imaging (PI) to separate them. No extra reference scans are required to generate either the model or the coil sensitivity maps. At each location in the reconstructed images, g -factor noise amplification is compared with predicted reconstruction errors to obtain an optimized solution. Acceleration factors greater than the number of receiver coils are possible, but are limited by the sparseness of the dynamic content and the signal-to-noise ratio (SNR) (in DCE-MRA the latter is dominant). Temporal fidelity was validated for up to a factor 10 speed-up using retrospectively undersampled data from a six-coil array. The method was tested on volunteers using fivefold prospective undersampling. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Modeling and analysis of thickness gradient and variations in vacuum-assisted resin transfer molding processPOLYMER COMPOSITES, Issue 5 2008Jing Li As vacuum-assisted resin transfer molding (VARTM) is being increasingly used in aerospace applications, the thickness gradient and variation issues are gaining more attention. Typically, thickness gradient and variations result from the infusion pressure gradient during the process and material variations. Pressure gradient is the driving force for resin flow and the main source of thickness variation. After infusion, an amount of pressure gradient is frozen into the preform, which primarily contributes to the thickness variation. This study investigates the mechanism of the thickness variation dynamic change during the infusion and relaxing/curing processes. A numerical model was developed to track the thickness change of the bagging film free surface. A time-dependent permeability model as a function of compaction pressure was incorporated into an existing resin transfer molding (RTM) code for obtaining the initial conditions for relaxing/curing process. Control volume (CV) and volume of fluid (VOF) methods were combined to solve the free surface problem. Experiments were conducted to verify the simulation results. The proposed model was illustrated with a relatively complex part. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] The sourcing of technological knowledge: distributed innovation processes and dynamic changeR & D MANAGEMENT, Issue 4 2003Jeremy Howells This paper outlines the knowledge and technology sourcing practices of a range of key firms and organisations across the UK based on primary research, and analyses the key factors related to managing the technological knowledge boundaries of the firm. In particular, the paper considers the dynamic dimension considerations to such issues. As such it outlines important differences between short and long time horizons, before analysing in more detail some of the implications for firms of technological change over the long term. The paper seeks to highlight the importance of the time dimension in helping to explain why and how firms source technological knowledge externally and how they align their sourcing activities to their strategies associated with developing current and future capabilities. [source] Dynamic wavefront aberrations and visual acuity in normal and dry eyesCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2009Yan Wang MD Purpose:, The aim was to study the dynamic properties of wavefront aberrations and visual acuity in normal and dry eyes. Methods:, Thirty dry-eye patients and 27 normal subjects participated in this study. Multi-file mode of a Hartmann-Shack wavefront sensor was used to measure dynamic wavefront aberrations for a period of 45 seconds. Dynamic measurements of visual acuity (VA) were made for 150 seconds using a multi-functional VA tester. Standard deviation of the measurements (RMS or VA) over the testing period was used to estimate instability of the dynamic wavefront aberration and VA. Results:, For most subjects, both wavefront aberration and VA changed over time and the instability varied substantially among individuals. Blink-dependent fluctuation in wavefront aberration or VA was observed for some dry-eye subjects. On average, the dry-eye group had greater instability than the normal group in either the higher order wavefront aberrations (t = 2.09, p = 0.03, for OD; t = 3.76, p = 0.001, for OS) or the VA (t = 2.09, p = 0.02, for OD; t = 204, p = 0.03, for OS). Instability of VA in the dry-eye group was significantly correlated with blink rate (r = 0.28, p = 0.02). Conclusion:, Dynamic changes in wavefront aberrations and VA are highly individual dependent, while the dry eye tends to be less stable than the normal eye. The results suggest that tear-film fluctuation might play a role in determining dynamic wavefront aberration and VA, however, contributions from other factors should not be overlooked. For dry eye, dynamic change in VA depends on blink rate. [source] A Multiresolution Model for Soft Objects Supporting Interactive Cuts and LacerationsCOMPUTER GRAPHICS FORUM, Issue 3 2000Fabio Ganovelli Performing a really interactive and physically-based simulation of complex soft objects is still an open problem in computer animation/simulation. Given the application domain of virtual surgery training, a complete model should be quite realistic, interactive and should enable the user to modify the topology of the objects. Recent papers propose the adoption of multiresolution techniques to optimize time performance by representing at high resolution only the object parts considered more important or critical. The speed up obtainable at simulation time are counterbalanced by the need of a preprocessing phase strongly dependent on the topology of the object, with the drawback that performing dynamic topology modification becomes a prohibitive issue. In this paper we present an approach that couples multiresolution and topological modifications, based on the adoption of a particle systems approach to the physical simulation. Our approach is based on a tetrahedral decomposition of the space, chosen both for its suitability to support a particle system and for the ready availability of many techniques recently proposed for the simplification and multiresolution management of 3D simplicial decompositions. The multiresolution simulation system is designed to ensure the required speedup and to support dynamic changes of the topology, e.g. due to cuts or lacerations of the represented tissue. [source] Dynamic study of cerebral bioenergetics and brain function using in vivo multinuclear MRS approachesCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2005Wei Chen Abstract One of the greatest merits of nuclear magnetic resonance (NMR) methodology used in biomedical research and clinical settings is its capability of measuring various physiological parameters in vivo. Besides MR imaging (MRI), which has been routinely applied to obtain vital information in living organs at normal and diseased states, in vivo MR spectroscopy (MRS) provides an invaluable tool for determining metabolites, chemical reaction rates, bioenergetics, and their dynamic changes in the human and animals noninvasively. These MRS capabilities are further enhanced at high/ultrahigh magnetic fields because of significant gain in NMR detection sensitivity and improvement in the spectral resolution. Recent progress has shown that in vivo MRS holds great promise in many biomedical research areas,in particular, brain research. This article provides a broad review of (i) in vivo multinuclear MRS approaches, (ii) advanced MRS methodologies, and (iii) MRS applications for determining cerebral metabolism as well as bioenergetics at resting brain state and their dynamic changes in response to brain activation. © 2005 Wiley Periodicals, Inc. Concepts Magn Reson Part A 27A: 84-121, 2005 [source] | ||||||||||||||||||||||||||||||||||||||||||||||