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Interesting Observation (interesting + observation)
Selected AbstractsOxidation chemistry of acid-volatile sulfide during analysisENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2002Adrian M. Gonzalez Abstract The susceptibility of some components of sediment acid-volatile sulfide (AVS) to chemical oxidation is a critical factor impacting accurate measurement of AVS in sediment samples. This well-documented susceptibility to oxidation led to the requirement for oxygen-free conditions in the analytical method developed for AVS. In light of this acute potential to oxidize, the serendipitous finding that air can be used in the analysis of sediment AVS is counterintuitive and unexpected. To demonstrate and investigate this interesting observation, extraction experiments were performed using aqueous and solid-phase sulfide species. Experiments using air as the carrier gas showed a mean percentage recovery of sulfide matching that of traditional (nitrogen gas) analysis (i.e., >91%) and a time to completion of less than 30 min for aqueous sulfide and less than 60 min for sediment samples. These results are consistent with those of sulfide oxidation studies reported in the literature. Using air as the analytical carrier gas can provide an interesting alternative for developing an analytical method to determine AVS parameters in the field. [source] Interferon-, priming is involved in the activation of arginase by oligodeoxinucleotides containing CpG motifs in murine macrophagesIMMUNOLOGY, Issue 1pt2 2009Miriam V. Liscovsky Summary Recognition of microbial products by macrophages (M,) stimulates an inflammatory response and plays a critical role in directing the host immune response against infection. In the present work, we showed for the first time that synthetic oligodeoxynucleotides containing unmethylated cytosine guanine motifs (CpG) are able to stimulate, in the presence of interferon-, (IFN-,), both arginase and inducible nitric oxide synthase (iNOS) in murine M,. Unexpectedly, IFN-,, a cytokine believed to be an inhibitor of arginase activity, intervened in the activation of this enzyme. A significant increase in arginase activity was observed upon a short pre-incubation (1 hr) with IFN-, and subsequent CpG stimulation. Therefore, a very interesting observation of this study was that the CpG-mediated arginase activity is dependent on IFN-, priming. The increase in arginase activity as a result of stimulation with CpG plus IFN-,was correlated with augmented expression of the arginase II isoform. The use of pharmacological specific inhibitors revealed that arginase activity was dependent on p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated protein kinase (ERK), but independent of c-Jun N-terminal kinase (JNK) activation. This report reveals a singular effect of the combination of CpG and IFN-,, one of the mayor cytokines produced in response to CpG administration in vivo. [source] Pregnancy, but not the allergic status, influences spontaneous and induced interleukin-1, (IL-1,), IL-6, IL-10 and IL-12 responsesIMMUNOLOGY, Issue 1 2006Petra Amoudruz Summary In this study, we investigated how pregnancy influences cytokine production in response to stimulation of the innate and the adaptive immune system, respectively. Peripheral blood mononuclear cells (PBMCs) from allergic (n = 44) and non-allergic (n = 36) women were collected at three time-points: during the third trimester, at delivery and at a non-pregnant state 2 years after delivery. The production of interleukin-1, (IL-1,), IL-6, IL-10 and IL-12 was measured by enzyme-linked immunosorbent assay (ELISA) or enzyme-linked immunospot assay (ELISPOT). The spontaneous cytokine production, and the response following stimulation with agents that primarily activate the adaptive part of the immune system [phytohaemagglutinin (PHA), allergen extracts from cat and birch], or lipopolysaccharide (LPS) that activate innate immunity was measured in vitro. There was a significantly higher spontaneous in vitro production of IL-1,, IL-6 and IL-10 by PBMCs during pregnancy than 2 years after pregnancy, and this was not affected by the allergic status of the women. Conversely, in PHA-stimulated cell cultures there was a lower production of IL-10 and IL-12 during pregnancy than 2 years after pregnancy. LPS-induced IL-6 levels were significantly lower in PBMCs obtained during pregnancy than at 2 years after pregnancy. In addition, we made the interesting observation that in allergic women total immunoglobulin E (IgE) levels were significantly lower 2 years after pregnancy compared to the levels during pregnancy. Taken together, our results indicate that while atopic allergy in women does not have a substantial effect on cytokine production, pregnancy has an obvious effect on the immune system in terms of cytokine production as well as on the total IgE levels. [source] Rejection of periodic disturbances of unknown and time-varying frequencyINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2-3 2005Marc Bodson Abstract The paper reviews available methods for the rejection of periodic disturbances. Such disturbances are often encountered in active noise and vibration control, due to rotating machinery. The emphasis of the paper is on feedback control problems where reference sensors are not available. The case where the frequency of the disturbance is known is considered first. Two sets of algorithms are discussed: one based on the internal model principle of feedback control theory, and the second based on adaptive feedforward cancellation. An interesting observation is that algorithms originating from both approaches can be shown to be equivalent under certain conditions. When the frequency of the disturbance is unknown, an intuitive approach consists in combining a method for the rejection of disturbances of known frequency with a frequency estimator. Alternatively, one may seek to develop a stable adaptation mechanism so that the disturbance is cancelled asymptotically. While algorithms can be designed to adapt to plant and disturbance parameters, the most successful approaches use some limited plant information to adapt the magnitude, frequency, and phase parameters of the control signal. Applications are discussed throughout the paper. Copyright © 2004 John Wiley & Sons, Ltd. [source] Error resilient data transport in sensor network applications: A generic perspective,INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2009Rachit Agarwal Abstract The error recovery problem in wireless sensor networks is studied from a generic resource-constrained energy-optimization perspective. To characterize the features of error recovery schemes that suit the majority of applications, an energy model is developed and inferences are drawn based on a suitable performance metric. For applications that require error control coding, an efficient scheme is proposed based on an interesting observation related to shortened Reed,Solomon (RS) codes for packet reliability. It is shown that multiple instances (,) of RS codes defined on a smaller alphabet combined with interleaving results in smaller resource usage, while the performance exceeds the benefits of a shortened RS code defined over a larger alphabet. In particular, the proposed scheme can have an error correction capability of up to , times larger than that of the conventional RS scheme without changing the rate of the code with much lower power, timing and memory requirements. Implementation results show that such a scheme is 43% more power efficient compared with the RS scheme with the same code rate. Besides, such an approach results in 46% faster computations and 53% reduction in memory requirements. Copyright © 2008 John Wiley & Sons, Ltd. [source] The outcome of tactile touch on oxytocin in intensive care patients: a randomised controlled trialJOURNAL OF CLINICAL NURSING, Issue 19 2008Maria Henricson Aim., To explore the effects of five-day tactile touch intervention on oxytocin in intensive care patients. The hypotheses were that tactile touch increases the levels of oxytocin after intervention and over a six-day period. Background., Research on both humans and animals shows a correlation between touch and increased levels of oxytocin which inspired us to measure the levels of oxytocin in arterial blood to obtain information about the physiological effect of tactile touch. Design., Randomised controlled trial. Method., Forty-four patients from two general intensive care units, were randomly assigned to either tactile touch (n = 21) or standard treatment , an hour of rest (n = 23). Arterial blood was drawn for measurement of oxytocin, before and after both treatments. Results., No significant mean changes in oxytocin levels were found from day 1 to day 6 in the intervention group (mean ,3·0 pM, SD 16·8). In the control group, there was a significant (p = 0·01) decrease in oxytocin levels from day 1 to day 6, mean 26·4 pM (SD 74·1). There were no significant differences in changes between day 1 and day 6 when comparing the intervention group and control group, mean 23·4 pM (95% CI ,20·2,67·0). Conclusion., Our hypothesis that tactile touch increases the levels of oxytocin in patients at intensive care units was not confirmed. An interesting observation was the decrease levels of oxytocin over the six-day period in the control group, which was not observed in the intervention group. Relevance to clinical practice., Tactile touch seemed to reduce the activity of the sympathetic nervous system. Further and larger studies are needed in intensive care units to confirm/evaluate tactile touch as a complementary caring act for critically ill patients. [source] The natural course of cutaneous melanomaJOURNAL OF SURGICAL ONCOLOGY, Issue 4 2004Ulrike Leiter MD Abstract The natural course of cutaneous melanoma (CM) is determined by its metastatic spread and depends on tumor thickness, ulceration, gender, localization, and the histologic subtype of the primary tumor. CM metastasis develops via three main metastatic pathways and occurs as satellite or in-transit metastasis, as regional lymph node metastasis or as distant metastasis at the time of primary recurrence. About 50% of all CM patients with tumor progression firstly develop regional lymph node metastases. In the other 50% the first metastases are satellite or in-transit metastases (about 20%), or immediately distant metastases (about 30%). Development of distant metastasis appears to be an early event in metastatic spread and may in the majority of cases originate from the primary tumor, only few cases may develop secondarily to locoregional metastasis. Reporting of organ involvement in distant metastasis greatly differs between the results of imaging techniques and autopsy results in respect to the metastatic patterns detected, pointing out that there is a need of improved imaging systems. Proliferation, neovascularization, lymphangiogenesis, invasion, circulation, and embolism are important steps in the pathogenesis of CM metastasis, with tumor vascularity as an important independent significant prognostic factor. The expression of chemokine receptors in cancer cells associated with the expression of the respective chemokine receptor ligands in the target sites of the metastasis is an interesting observation which may stimulate the development of new therapeutic strategies. J. Surg. Oncol. 2004;86:172,178. © 2004 Wiley-Liss, Inc. [source] Single-crystal EPR studies of a perchlorate-bridged dimeric copper(II) complex with 2-[(4-methyl-pyridin-2-ylimino)-methyl]-phenolPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2007R. Srinivasan Abstract A new dimeric perchlorate-bridged copper(II) complex with the Schiff's base ligand 2-[(4-methyl-pyridin-2-ylimino)-methyl]-phenol has been synthesized. The complex has been characterized using elemental analysis, ultraviolet,visible and infrared spectroscopy, conductivity, magnetic studies and EPR techniques. Single-crystal EPR studies indicate that zero-field splitting (D) is relatively small, and that the half-field transition is not observed due to its low intensity. An interesting observation in the frozen solution is that the low-field side of the zero-field splitting line splits into seven lines, due to interaction between the two copper ions. The magnetic susceptibility data indicate a weak ferromagnetic property and that the complex is a 1:2 electrolyte. Another set of EPR resonances corresponding to higher D and g values, compared to the system reported, are noticed, whose origin is not yet known. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Analysis of multiple crystal forms of Bacillus subtilis BacB suggests a role for a metal ion as a nucleant for crystallizationACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2010M. Rajavel Bacillus subtilis BacB is an oxidase that is involved in the production of the antibiotic bacilysin. This protein contains two double-stranded ,-helix (cupin) domains fused in a compact arrangement. BacB crystallizes in three crystal forms under similar crystallization conditions. An interesting observation was that a slight perturbation of the crystallization droplet resulted in the nucleation of a different crystal form. An X-ray absorption scan of BacB suggested the presence of cobalt and iron in the crystal. Here, a comparative analysis of the different crystal forms of BacB is presented in an effort to identify the basis for the different lattices. It is noted that metal ions mediating interactions across the asymmetric unit dominate the different packing arrangements. Furthermore, a normalized B -factor analysis of all the crystal structures suggests that the solvent-exposed metal ions decrease the flexibility of a loop segment, perhaps influencing the choice of crystal form. The residues coordinating the surface metal ion are similar in the triclinic and monoclinic crystal forms. The coordinating ligands for the corresponding metal ion in the tetragonal crystal form are different, leading to a tighter packing arrangement. Although BacB is a monomer in solution, a dimer of BacB serves as a template on which higher order symmetrical arrangements are formed. The different crystal forms of BacB thus provide experimental evidence for metal-ion-mediated lattice formation and crystal packing. [source] Coupled HM analysis using zero-thickness interface elements with double nodes,Part II: Verification and applicationINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 18 2008J. M. Segura Abstract In a companion Part I of this paper (Int. J. Numer. Anal. Meth. Geomech. 2008; DOI: 10.1002/nag.735), a coupled hydro-mechanical (HM) formulation for geomaterials with discontinuities based on the finite element method (FEM) with double-node, zero-thickness interface elements was developed and presented. This Part II paper includes the numerical solution of basic practical problems using both the staggered and the fully coupled approaches. A first group of simulations, based on the classical consolidation problem with an added vertical discontinuity, is used to compare both the approaches in terms of accuracy and convergence. The monolithic or fully coupled scheme is also used in an application example studying the influence of a horizontal joint in the performance of a reservoir subject to fluid extraction. Results include a comparison with other numerical solutions from the literature and a sensitivity analysis of the mechanical parameters of the discontinuity. Some simulations are also run using both a full non-symmetric and a simplified symmetric Jacobian matrix. On top of verifying the model developed and its capability to reflect the conductivity changes of the interface with aperture changes, the results presented also lead to interesting observations of the numerical performance of the methods implemented. Copyright © 2008 John Wiley & Sons, Ltd. [source] Hall effects for MHD Oldroyd 6-constant fluid flows using finite element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2009M. Sajid Abstract This paper numerically investigates the influence of Hall current on the steady flows of an Oldroyd 6-constant fluid between concentric cylinders. The flow analysis has been performed by employing finite element method. Two flow problems are considered. These problems have been recently solved by Rana et al. (Chaos, Solitons and Fractals, in press). Here the main equation governing the flow problems in (Chaos, Solitons and Fractals, in press) is corrected first and then used in the simulation. Finally, the interesting observations are obtained by plotting graphs. Copyright © 2008 John Wiley & Sons, Ltd. [source] Numerical analysis of interfacial two-dimensional Stokes flow with discontinuous viscosity and variable surface tensionINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 5 2001Zhilin Li Abstract A fluid model of the incompressible Stokes equations in two space dimensions is used to simulate the motion of a droplet boundary separating two fluids with unequal viscosity and variable surface tension. Our theoretical analysis leads to decoupled jump conditions that are used in constructing the numerical algorithm. Numerical results agree with others in the literature and include some new findings that may apply to processes similar to cell cleavage. The method developed here accurately preserves area for our test problems. Some interesting observations are obtained with different choices of the parameters. Copyright © 2001 John Wiley & Sons, Ltd. [source] Sphingolipids in rat model of transient focal cerebral ischemia: implication for stroke injuryJOURNAL OF NEUROCHEMISTRY, Issue 2002M. Khan Lipids are essential for signal transduction in response to trauma leading to neurodegeneration. Ceramide is an important mediator of apoptosis and cell proliferation. We studied the involvement of ceramide/sphingomyelin pathway in rat brain (stroke model) after 45 min ischemia followed by 24-h reperfusion. Ischemia was performed through occlusion of right middle cerebral artery (MCA). The level of ceramide was found increased (70,100% in ischemic side of brain v/s contralateral side of brain). Sphingomyelin levels were also decreased by 20,25% in ischemic brain v/s contralateral side of brain. Increase in ceramide and decrease in sphingomyelin were in good agreement with observed apoptotic cell loss (TUNEL assay) and decrease in the level of cardiolipin (a mitochondrian specific phospholipids) in affected ischemic brain. N-acetyl cysteine (NAC), a therapeutic agent recognized as potent antioxidant provided protective effect. Pretreatment with NAC before ischemia reduced the infarct volume size, suppressed apoptosis, restored cardiolipin level and decreased the levels of free fatty acids. However, NAC did not normalize the ceramide level. These interesting observations raise a question about the role of ceramide and its relationship with apoptosis and oxidative stress in rat brain ischemia. Acknowledgements:, Supported by NIH grants NS-40144, NS-40810, NS-22576, NS-34741 and NS-37766. [source] Profound changes in the GH,IGF-I system in adolescent girls with IDDM: can IGFBP1 be used to reflect overall glucose regulation?PEDIATRIC DIABETES, Issue 3 2000MU Halldin Disturbances in the relations between insulin, growth hormone (GH) and insulin-like growth factor I (IGF-I) may be a major cause behind deteriorated metabolic control in adolescent girls with type I diabetes. These patients have increased GH secretion and low IGF-I concentrations. The aim of this study was to identify possible endocrine mechanisms behind good and poor glycaemic control in such girls, focusing on the insulin,GH,IGF-I axis. Ten girls with well-controlled insulin-dependent diabetes mellitus (IDDM), hemoglobin A1c (HbA1c) 6.5±0.4% (normal range 3.9,5.2%) and nine healthy controls were investigated and compared with 11 girls with poor glucose regulation, HbA1c 10.9±0.4%, and their corresponding controls. Serum profiles of glucose, insulin, GH and IGF-binding protein 1 (IGFBP1) were analysed in addition to IGF-I and HbA1c. Two interesting observations were made. GH concentrations were equally elevated in the two diabetic groups regardless of metabolic control (mean 24 h GH , girls with poorly controlled diabetes 10.0±1.0 mU/L vs 9.8±1.7 , girls with well-controlled diabetes; p=ns). Likewise, the IGF-I concentrations were reduced to the same extent (233±19 vs 242±23 ,g/L; p=0.75). Secondly, despite similar insulin concentrations (mean 24 h insulin , girls with poorly controlled diabetes 22.9±2.6 and girls with well-controlled diabetes 27.3±2.9 mU/L, respectively; p=0.26), there was a marked difference in IGFBP1 concentrations between the two groups with IDDM (mean IGFBP1 , girls with poorly controlled diabetes 70.5±9.1 ,g/L vs girls with well-controlled diabetes 28.6±3.3; p<0.001). Despite equally elevated GH concentrations that may induce insulin resistance, the markedly lower concentrations of IGFBP1 in the well-controlled group indicate a higher hepatic insulin sensitivity in these girls compared with those with a poor control. Furthermore, in spite of similar total IGF-I concentrations, the lower IGFBP1 concentrations may result in higher IGF-I bioactivity in the well-controlled group. This may be reflected in better growth of the well-controlled group whose height of 168.7±0.9 vs 163.6±1.2 cm was significantly different (p<0.004). IGFBP1 may be a marker of overall insulinization in adolescents with type 1 diabetes, independent of the absolute insulin dose used for therapy. [source] Estrogen signaling pathway and its imaging in human breast cancerCANCER SCIENCE, Issue 10 2009Shin-ichi Hayashi Recent remarkable progress in hormonal therapy has provided great benefit to breast cancer patients, but it also evokes novel issues: how accurately can the efficacy of each hormonal therapy be predicted and how can hormonal therapy,resistant patients be treated? These clinically important issues must be closely related to the biological events in each cancer, such as the alteration of intracellular multiple estrogen signaling pathways and the estrogen-related cancer microenvironment, which has recently revealed by molecular biological studies on estrogen and its receptors. However, the estrogen signaling status in individual breast cancers has not been clarified yet. Here we present the context of these issues and introduce our study of new tools which enable the visualization of estrogen signals in individual cancers. The assessment of estrogen receptor (ER)-, activity in individual cancers or ER-activating ability of the cancer microenvironment in each breast cancer patient revealed several new findings and interesting observations. We hope that these approaches provide new clues about the estrogen-dependent mechanisms of breast cancer development, and will be useful to advance the diagnosis and treatment of breast cancer patients. (Cancer Sci 2009; 100: 1773,1778) [source] | ||||||||||||||||