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Ln
Kinds of Ln Terms modified by Ln Selected AbstractsMaxwell Fluid Model for Generation of Stress,Strain Curves of Viscoelastic Solid Rocket PropellantsPROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 4 2010Himanshu Shekhar Abstract Solid rocket propellants are modeled as Maxwell Fluid with single spring and single dashpot in series. Complete stress,strain curve is generated for case-bonded composite propellant formulations by taking suitable values of spring constant and damping coefficient. Propellants from same lot are tested at different strain rate. It is observed that change in spring constant, representing elastic part is very small with strain rate but damping constant varies significantly with variation in strain rate. For a typical propellant formulation, when strain rate is varied from 0.00037 to 0.185 per second, spring constant (K) changed from 5.5 to 7.9,MPa, but damping coefficient (D) varied from 1400 to 4,MPas. For all strain rates, stress,strain curve is generated using developed Maxwell model and close matching with actual test curve is observed. This indicates validity of Maxwell fluid model for case-bonded solid propellant formulations. It is observed that with increases in strain rate, spring constant increases but damping coefficient decreases representing solid rocket propellant as a true viscoelastic material. It is also established that at higher strain rate, damping coefficient becomes negligible as compared to spring constant. It is also observed that variation of spring constant is logarithmic with strain rate and that of damping coefficient follows a power law. The correlation coefficients are introduced to ascertain spring constants and damping coefficients at any strain rate from that at a reference strain rate. Correlation for spring constant needs a coefficient "H," which is function of propellant formulation alone and not of test conditions and the equation developed is K2=(K1 - H)×{ln(d,2/dt)/ln(d,1/dt)}+H. Similarly for damping coefficient (D) also another constant "S" is introduced and prediction formula is given by D2=D1×{(d,2/dt)/(d,1/dt)}S. Evaluating constants "H" and "S" at different strain rates validate this mathematical formulation for different propellant formulations. Close matching of test and predicted stress,strain curve indicates propellant behavior as viscoelastic Maxwell Fluid. Uniqueness of approach is to predict complete stress,strain curves, which are not attempted by any other researchers. [source] Exact and approximative algorithms for coloring G(n,p)RANDOM STRUCTURES AND ALGORITHMS, Issue 3 2004Amin Coja-Oghlan We investigate the problem of coloring random graphs G(n, p) in polynomial expected time. For the case p , 1.01/n, we present an algorithm that finds an optimal coloring in linear expected time. For p , ln6(n)/n, we give algorithms which approximate the chromatic number within a factor of O( ). We also obtain an O(/ln(np))-approximation algorithm for the independence number. As an application, we propose an algorithm for deciding satisfiability of random 2k -SAT formulas over n propositional variables with , ln7(n)nk clauses in polynomial expected time. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2004 [source] On the noise sensitivity of monotone functionsRANDOM STRUCTURES AND ALGORITHMS, Issue 3 2003Elchanan Mossel It is known that for all monotone functions f : {0, 1}n , {0, 1}, if x , {0, 1}n is chosen uniformly at random and y is obtained from x by flipping each of the bits of x independently with probability , = n,,, then P[f(x) , f(y)] < cn,,+1/2, for some c > 0. Previously, the best construction of monotone functions satisfying P[fn(x) , fn(y)] , ,, where 0 < , < 1/2, required , , c(,)n,,, where , = 1 , ln 2/ln 3 = 0.36907 ,, and c(,) > 0. We improve this result by achieving for every 0 < , < 1/2, P[fn(x) , fn(y)] , ,, with: , = c(,)n,, for any , < 1/2, using the recursive majority function with arity k = k(,); , = c(,)n,1/2logtn for t = log2 = .3257 ,, using an explicit recursive majority function with increasing arities; and , = c(,)n,1/2, nonconstructively, following a probabilistic CNF construction due to Talagrand. We also study the problem of achieving the best dependence on , in the case that the noise rate , is at least a small constant; the results we obtain are tight to within logarithmic factors. © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 23: 333,350, 2003 [source] Synthesis and characterization of fine lithium niobate powders by sol- gel methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2007L. H. Wang Abstract Lithium niobate (LN) nanocrystal powders were prepared by low-temperature sol-gel method. Dihydrate lithium acetate as lithium source, and niobium chloride as niobium source were used as starting materials. The gel and powders were characterized by thermogravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), transmission electronmicroscopy (TEM) and Fourier transform infrared (FTIR) spectra. The results show that when the gel was heat-treated at 600°C, the fine LN nanocrystals with the size of 40-60 nm were obtained, and the size of the powders become larger with the heat-treated temperature increasing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] ,-Dystroglycan is essential for the induction of Egr3, a transcription factor important in muscle spindle formationDEVELOPMENTAL NEUROBIOLOGY, Issue 7 2010Stacey Williams Abstract Muscle spindle fibers are specialized stretch receptors that allow the perception and coordination of limb movement. The differentiation of these specialized structures is initiated by signals derived from the in growing Ia sensory neurons during development. While the direct molecular signaling mechanisms between sensory neurons and developing muscle at nascent spindle fibers have been well documented in past studies the roles of muscle basal lamina components on this process have not previously been described. As such, our initial experiments addressed potential roles for agrin (AGRN) and laminin (LN) in the expression of the transcription factor Egr3. Levels of Egr3 were monitored using immunoblot analysis and both basal lamina molecules proved effective in inducing Erg3 expression. Previous work had established neuregulin (NRG) as a critical signaling component in spindle fiber development so blocking experiments with NRG and ErbB inhibitors were then used to determine if LN-induced Egr3 expression was occurring as a result of NRG-ErbB signaling and not via other, novel pathway. Inhibiting signaling through this pathway did indeed reduce the expression of Egr3. Finally, we looked at ,-dystrogylcan, a shared receptor for AGRN and LN at neuromuscular junctions. Using a ,-dystroglycan (,-DG) silenced muscle cell line and an anti-,-DG antibody we attempted to block basal lamina/,-DG interactions. Again, and in both instances, Egr3 expression was significantly decreased. Taken together, analysis of the results from these experiments revealed that indeed AGRN, LN, and ,-DG influence Egr3 levels and therefore may play an important role in spindle fiber differentiation. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70:498,507, 2010 [source] Laminin and fibronectin modulate inner ear spiral ganglion neurite outgrowth in an in vitro alternate choice assayDEVELOPMENTAL NEUROBIOLOGY, Issue 13 2007Amaretta R. Evans Abstract Extracellular matrix (ECM) molecules have been shown to function as cues for neurite guidance in various populations of neurons. Here we show that laminin (LN) and fibronectin (FN) presented in stripe micro-patterns can provide guidance cues to neonatal (P5) inner ear spiral ganglion (SG) neurites. The response to both ECM molecules was dose-dependent. In a LN versus poly- L -lysine (PLL) assay, neurites were more often observed on PLL at low coating concentrations (5 and 10 ,g/mL), while they were more often on LN at a high concentration (80 ,g/mL). In a FN versus PLL assay, neurites were more often on PLL than on FN stripes at high coating concentrations (40 and 80 ,g/mL). In a direct competition between LN and FN, neurites were observed on LN significantly more often than on FN at both 10 and 40 ,g/mL. The data suggest a preference by SG neurites for LN at high concentrations, as well as avoidance of both LN at low and FN at high concentrations. The results also support a potential model for neurite guidance in the developing inner ear in vivo. LN, in the SG and osseus spiral lamina may promote SG dendrite growth toward the organ of Corti. Within the organ of Corti, lower concentrations of LN may slow neurite growth, with FN beneath each row of hair cells providing a stop or avoidance signal. This could allow growth cone filopodia increased time to sample their cellular targets, or direct the fibers upward toward the hair cells. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007 [source] AN ENDOCRINE CELL CARCINOMA WITH GASTRIC-AND-INTESTINAL MIXED PHENOTYPE ADENOCARCINOMA COMPONENT IN THE STOMACHDIGESTIVE ENDOSCOPY, Issue 4 2009Tsutomu Mizoshita A 77-year-old man complained of bodyweight loss, and a Borrmann 3 type lesion was observed endoscopically in the anterior wall of angular region of the stomach. The endocrine cell carcinoma (ECC) having the cytoplasmic staining of chromogranin A (CgA) was detected pathologically in the biopsy samples. The patient underwent distal gastrectomy plus systemic lymph node (LN) dissection (D2 LN dissection), and pathological examination revealed ECC invading the subserosa, and no LN metastasis (pT2N0M0). None of the gastric and intestinal endocrine cell marker expression was apparent in the ECC cells. The lesion also contained a moderately differentiated type tubular adenocarcinoma component, which was judged to be gastric-and-intestinal mixed (GI type) phenotype, using gastric and intestinal exocrine cell markers. After the surgery, he left the hospital and started oral doxifluridine (600 mg/day). The patient now (March 2008, about 19 months since the surgery) continues this chemotherapy with no recurrence. In conclusion, we experienced ECC with a GI type adenocarcinoma component. The ECC cases with the GI type adenocarcinoma component may have a relatively good prognosis, being similar to the results of advanced gastric cancers from the viewpoint of gastric and intestinal phenotypic expression. [source] Short-term symptom and quality-of-life comparison between laparoscopic Nissen and Toupet fundoplicationsDISEASES OF THE ESOPHAGUS, Issue 1 2009R. Radajewski SUMMARY Laparoscopic antireflux surgery is an established method of treatment of gastroesophageal reflux disease (GERD). This study evaluates the efficacy of Nissen versus Toupet fundoplication in alleviating the symptoms of GERD and compares the two techniques for the development of post-fundoplication symptoms and quality of life (QOL) at 12 months post-surgery. In this prospective consecutive cohort study, 94 patients presenting for laparoscopic antireflux surgery underwent either laparoscopic Nissen fundoplication (LN) (n = 51) from February 2002 to February 2004 or a laparoscopic Toupet fundoplication (LT) (n = 43) from March 2004 to March 2006, performed by a single surgeon (G. S. S.). Symptom assessment, a QOL scoring instrument, and dysphagia questionnaires were applied pre- and postoperatively. At 12 months post-surgery, patient satisfaction levels in both groups were high and similar (LT: 98%, LN: 90%; P = 0.21). The proportion of patients reporting improvement in their reflux symptoms was similar in both groups (LT: 95%, LN: 92%; P = 0.68), as were post-fundoplication symptoms (LT: 30%, LN: 37%; P = 0.52). Six patients in the Nissen group required dilatation for dysphagia compared with one in the Toupet group (LT: 2%, LN: 12%; P = 0.12). One patient in the Nissen group required conversion to Toupet for persistent dysphagia (P = 0.54). In this series, overall symptom improvement, QOL, and patient satisfaction were equivalent 12 months following laparoscopic Nissen or Toupet fundoplication. There was no difference in post-fundoplication symptoms between the two groups, although there was a trend toward a higher dilatation requirement and reoperation after Nissen fundoplication. [source] Reduction rate of lymph node metastasis as a significant prognostic factor in esophageal cancer patients treated with neoadjuvant chemoradiation therapyDISEASES OF THE ESOPHAGUS, Issue 2 2007S. Aiko SUMMARY., Tumor regression is used widely as a measure of tumor response following radiation therapy or chemoradiation therapy (CRT). In cases of esophageal cancer, a different pattern of tumor shrinkage is often observed between primary tumors and metastatic lymph nodes (MLNs). Regression of MLNs surrounded by normal tissue may be a more direct measure of the response to CRT than regression of a primary tumor as exfoliative mechanical clearance does not participate in shrinkage of MLNs. In this study we evaluated the significance of the reduction rate (RR) of MLNs as a prognostic factor in esophageal cancer patients treated with neoadjuvant CRT. Forty-two patients with marked MLNs were selected from 93 patients with esophageal carcinoma who had received neoadjuvant CRT. The RRs of the primary tumor and the MLNs were calculated from computed tomography scans. In 20 patients, surgical resection was carried out following CRT. Univariate analysis was used to determine which of the following variables were related to survival: size of the primary tumor and MLNs; RRs of both lesions; degree of lymph node (LN) metastasis; clinical stage; and surgical resection. Multivariate analysis was then performed to assess the prognostic relevance of each variable. The primary tumor was larger than the MLNs in 69% of patients before CRT and in 40% of patients after CRT. In 79% of the patients, the RR of the primary tumor was greater than the RR of the MLNs. The results of the univariate analyses showed that a high RR of the MLNs and surgical resection after CRT were associated with significantly improved survival. The multivariate analysis demonstrated that the RR of MLNs had the strongest influence on survival. The RR of LN metastasis should be evaluated as an important prognostic predictor in patients with marked LN metastasis of esophageal cancer treated with CRT. [source] Application of CE with novel dynamic coatings and field-amplified sample injection to the sensitive determination of isomeric benzoic acids in atmospheric aerosols and vehicular emissionELECTROPHORESIS, Issue 19 2007Ewa Dabek-Zlotorzynska Dr. Abstract A simple and reliable CE method with direct UV detection has been developed to separate eight isomeric benzoic acids in atmospheric aerosols and vehicular emission without complex sample pretreatment. Optimal electrophoretic conditions, with migration times under 5,min, were obtained by using a 50,mM acetate buffer (pH,4.7) containing a dynamic surface coating EOTrolÔ LN (0.005% w/v). The separations were carried out in a cathode to anode direction (,30,kV) allowing the low cathodal EOF (,1×10,9,m2V,1s,1) to extend the effective separation by slowing the movement of the studied aromatic acids. Moreover, the sensitivity of the method at 200,nm was enhanced by using a field-amplified sample injection (FASI) with electrokinetic (EK) sample injection (,2,kV, 60,s). Prior to sample injection, a short water plug (3,s at 0.5,psi) was introduced. Under these conditions, the method was capable of detecting the analytes in deionized water with LODs (S/N,=,3) as low as 0.1,,g/L for most of the studied acids. In the presence of 10,mg/L of sulphate (added to simulate a sample matrix), LODs ranged from 0.26 to 0.62,,g/L. The validation of the method has proven an excellent separation performance and accuracy for the determination of isomeric benzoic acids in the studied matrices. [source] A molecular analysis of biclonal follicular lymphoma: further evidence for bone marrow origin and clonal selectionEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2009Yuichi Nakamura Abstract We report a follicular lymphoma (FL) case presenting the coexistence of two tumor cell subpopulations in lymph node (LN) and bone marrow (BM), which exhibited an inverse pattern of immunoglobulin light (IgL) chain gene rearrangement and expression: Ig,,,+ in LN and Ig,+,, in BM. These tumor clones shared an identical BCL2-IgH recombination, accompanying t(14;18)(q32;q21) translocation, and an identical variable, diversity and joining segments joining with clone-specific VH somatic hypermutations on the untranslocated IgH allele. Our study provides further evidence that FL clones, originating from common progenitor cells, can be developed independently at different sites and with different IgL expression after immune selection. [source] The pericyte and stromal cell marker CD248 (endosialin) is required for efficient lymph node expansionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2010Siân Lax Abstract CD248 is a cell surface receptor that specifically identifies fibroblasts and pericytes during development and in association with cancer and inflammation. However, its function is poorly defined and its role in lymphoid organs not studied. Here, we used (4-hydroxy-3-nitrophenyl)acetyl chicken ,-globulin immunisation and mice lacking CD248 to study whether CD248 modulates popliteal LN (pLN) expansion and subsequent immune responses. We have found that CD248 is required for complete pLN expansion but not for co-ordination of B and T cell compartmentalisation or antibody production following (4-hydroxy-3-nitrophenyl)acetyl chicken ,-globulin immunisation. In vitro, we show that CD248 expression in human MG63 stromal cells and mouse embryonic fibroblasts leads to a pro-proliferative and pro-migratory phenotype. This correlates with a proliferating CD248+ population observed in vivo during pLN expansion. Taken together, these data highlight a role for CD248 in secondary lymphoid organ remodelling during adaptive immune responses. [source] CD8,+ DC are not the sole subset cross-presenting cell-associated tumor antigens from a solid tumorEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2010Alison M. McDonnell Abstract One of the clear paradoxes in tumor immunology is the fact that cross-presentation of cell-associated tumor antigens to CD8+ T cells is efficient, yet CTL generation is weak, and tumors continue to grow. We examined, for the first time whether this may be due to alterations in the phenotype or function of cross-presenting DC using a solid tumor model expressing a membrane bound neo-antigen (hemagglutinin, HA). Tumor antigen was constitutively cross-presented in the tumor-draining LN throughout tumor progression by CD11c+ DC. Further analysis revealed that both CD8,+ and CD8,, DC subsets, but not plasmacytoid DC, were effective at cross-presenting HA tumor antigen. The proportions of DC subsets in the tumor-draining LN were equivalent to those seen in the LN of naïve mice; however, a significant increase in the expression of the potential inhibitory B7 molecule, B7-DC, was noted and appeared to be restricted to the CD8,, DC subset. Therefore LN resident CD8,+ DC are not the sole DC subset capable of cross-presenting cell-associated tumor antigens. Migratory tumor DC subsets with altered co-stimulatory receptor expression may contribute to induction and regulation of tumor-specific responses. [source] A two-step model for Langerhans cell migration to skin-draining LNEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Eduardo J. Villablanca Abstract Although the role of Langerhans cells (LC) in skin immune responses is still a matter of debate, it is known that LC require the chemokine receptor CCR7 for migrating to skin-draining LN. A report in the current issue of the European Journal of Immunology unfolds some of the intricacies of LC migration, showing that LC need CXCR4, but not CCR7, for their migration from the epidermis to the dermis. Thus, LC migration to skin-draining LN occurs in two distinct phases: a first step from the epidermis to the dermis regulated by CXCR4 and a second CCR7-dependent step from the dermis to LN. Here we discuss the potential implications of this new two-step LC migration paradigm. [source] IL-12 and IL-18 down-regulate B cell migration in an Ly49D-dependent mannerEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2007Gili Hart Abstract In order to complete their maturation and participate in the humoral immune response, immature B cells that leave the bone marrow are targeted to specific areas in the spleen, where they differentiate into mature cells. Previously, we showed that immature B cells actively down-regulate their integrin-mediated migration to LN or to sites of inflammation, enabling their targeting to the spleen. This inhibition is mediated by IFN-,, which is transcribed and secreted at low levels by these immature B cells; its expression is subsequently down-regulated following B cell maturation. The activating and inhibitory MHC class,I receptors, Ly49D and Ly49G2, regulate IFN-, secretion in B cells, preventing their migration to antigen-enriched sites and their premature encounter with an antigen, while enabling their entry into the LN when mature. In the present study, we elucidate the pathways by which the Ly49 receptors regulate IFN-, levels. We show that Ly49D stimulation triggers a signaling cascade that increases transcription of both IL-12B and IL-18; these, in turn, can interact with their specific receptors, which are expressed at elevated levels on immature B cells. Ligation of the IL-12B and IL-18 receptors induces the secretion of IFN-,, thereby regulating their cytoskeleton rearrangement and migration. [source] T lymphocyte rolling and recruitment into peripheral lymph nodes is regulated by a saturable density of L-selectin (CD62L)EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2007Elena Galkina Dr. Abstract L-selectin mediates tethering and rolling of lymphocytes in high endothelial venules (HEV) of lymph nodes (LN) and of leukocytes at inflammatory sites. We used transgenic mice expressing varying levels of wild-type or a non-cleavable mutant form of L-selectin on T cells to determine the relationship between L-selectin density, tethering and rolling, and migration into LN. T cells expressing supraphysiological levels of either wild-type or non-cleavable L-selectin showed rolling parameters similar to C57BL/6 T cells in hydrodynamic flow assays and during rolling in Peyer's patch HEV. In contrast, PMA- or antigen-activated T cells and L-selectin+/, T cells expressing subphysiological levels of L-selectin showed reduced numbers of rolling cells with increased rolling velocity. Short-term homing studies showed that elevated expression of L-selectin above physiological levels had no effect on T cell migration to LN; however, low L-selectin expression resulted in reduced T cell homing to LN. Thus, T lymphocyte migration into LN is regulated by the density of cell surface L-selectin. In addition, there is a saturable density of L-selectin required for optimal homing to PLN in C57BL/6 mice, the L-selectin level on circulating naive T cells promotes optimal homing, and increased expression above saturating levels promotes no further increase in T cell recruitment. [source] Development of nephritis but not sialadenitis in autoimmune-prone BAFF transgenic mice lacking marginal zone B cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2006Carrie Abstract B cell-activating factor belonging to the TNF family (BAFF) is a B cell survival factor required for B cell maturation. BAFF transgenic (Tg) mice develop autoimmune disorders characterized by autoantibody production, which leads to nephritis and salivary gland destruction (sialadenitis), features reminiscent of systemic lupus erythematosus and Sjögren's syndrome (SS), respectively. Disease in BAFF Tg mice correlates with the expansion of the marginal zone (MZ) B cell compartment and the abnormal presence of MZ-like B cells in the blood, LN and inflamed salivary glands, suggesting a role for these cells in BAFF-induced autoimmunity. Lymphotoxin-, (LT,)-deficient mice show disrupted splenic architecture, lack MZ B cells and some peripheral LN, and are unable to mount T cell-dependent immune responses. BAFF Tg mice lacking LT, (LT,,-BTg) retained these defects, yet still developed nephritis associated with the presence of B-1 B cells in the kidneys. However, in contrast to old BAFF Tg mice, aging LT,,-BTg mice no longer developed sialadenitis. Thus, autoimmune disorders in BAFF Tg mice are possibly events coordinated by MZ and B-1 B cells at separate anatomical sites. [source] In vitro differentiation of lineage-negative bone marrow cells into microglia-like cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2010Daisuke Noto Abstract Microglia are believed to be the only resident immune cells in the CNS, originating from hematopoietic-derived myeloid cells and invading the CNS during development. However, the detailed mechanisms of differentiation and transformation of microglial cells are not fully understood. Here, we demonstrate that murine microglial cells show two morphological forms in vitro, namely, small round cells expressing CD11b, Iba1, triggering receptor expressing on myeloid cells-2 (TREM2), and weakly expressing major histocompatibility complex class II and large flat cells expressing only CD11b and Iba1. Moreover, lineage-negative bone marrow (LN) cells cultured with primary mixed glial culture cells could differentiate into only the small round microglia-like cells, despite the absence of CCR2 and Gr-1 expression. Addition of macrophage colony stimulating factor (M-CSF) to LN cell culture allowed the proliferation and expression of TREM2 in LN cells, and the addition of neutralizing anti-M-CSF antibodies suppressed the proliferation of LN cells despite the expression of TREM2. When LN cells were cultured with M-CSF, the number of small round cells in the culture was considerably low, indicating that the small round morphology of the immature cells is not maintained in the presence of only M-CSF. On the other hand, when LN cells were grown in the presence of astrocytes, the small round cells were maintained at a concentration of approximately 30% of the total population. Therefore, cell,cell contact with glial cells, especially astrocytes, may be necessary to maintain the small round shape of the immature cells expressing TREM2. [source] Evaluating the linear normalization technique for deriving J -resistance curvesFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 2 2003J. R. TARPANI ABSTRACT In this paper, results from the linear normalization (LN) technique of Reese and Schwalbe for deriving J- crack resistance (J,R) curves have been compared, related to J,,a (J -integral,ductile crack growth) data points, to those obtained from traditional elastic compliance technique. Research results regarding a nuclear grade steel exhibiting a wide range of elastic,plastic fracture resistance agree quite well for both techniques until a certain level of toughness of the material. Below this critical level, LN produces inconsistent results for the sub-sized compact tension specimens (0.4T C[T]). The evidence suggests that the loss of applicability of the LN technique can be determined on the basis of the , plastic factor (,pl) for the best linear correlation achieved for ,PN,,a (normalised load gradient,ductile crack growth) data. [source] Seasonal changes in the effects of elevated CO2 on rice at three levels of nitrogen supply: a free air CO2 enrichment (FACE) experimentGLOBAL CHANGE BIOLOGY, Issue 6 2003HAN-YONG KIM Abstract Over time, the stimulative effect of elevated CO2 on the photosynthesis of rice crops is likely to be reduced with increasing duration of CO2 exposure, but the resultant effects on crop productivity remain unclear. To investigate seasonal changes in the effect of elevated CO2 on the growth of rice (Oryza sativa L.) crops, a free air CO2 enrichment (FACE) experiment was conducted at Shizukuishi, Iwate, Japan in 1998,2000. The target CO2 concentration of the FACE plots was 200 µmol mol,1 above that of ambient. Three levels of nitrogen (N) were supplied: low (LN, 4 g N m,2), medium [MN, 8 (1998) and 9 (1999, 2000) g N m,2] and high N (HN, 12 and 15 g N m,2). For MN and HN but not for LN, elevated CO2 increased tiller number at panicle initiation (PI) but this positive response decreased with crop development. As a result, the response of green leaf area index (GLAI) to elevated CO2 greatly varied with development, showing positive responses during vegetative stages and negative responses after PI. Elevated CO2 decreased leaf N concentration over the season, except during early stage of development. For MN crops, total biomass increased with elevated CO2, but the response declined linearly with development, with average increases of 32, 28, 21, 15 and 12% at tillering, PI, anthesis, mid-ripening and grain maturity, respectively. This decline is likely to be due to decreases in the positive effects of elevated CO2 on canopy photosynthesis because of reductions in both GLAI and leaf N. Up to PI, LN-crops tended to have a lower response to elevated CO2 than MN- and HN-crops, though by final harvest the total biomass response was similar for all N levels. For MN- and HN-crops, the positive response of grain yield (ca. 15%) to elevated CO2 was slightly greater than the response of final total biomass while for LN-crops it was less. We conclude that most of the seasonal changes in crop response to elevated CO2 are directly or indirectly associated with N uptake. [source] DEC-205lo Langerinlo neonatal Langerhans' cells preferentially utilize a wortmannin-sensitive, fluid-phase pathway to internalize exogenous antigenIMMUNOLOGY, Issue 4 2003Bernadette M. Bellette Summary Antigen treatment of neonatal epidermis results in antigen-specific immune suppression. Compared with adult counterparts, neonatal Langerhans' cells (LC) demonstrate an impaired ability to transport antigen to the lymph node (LN). As it is possible that neonatal LC have a reduced ability to endocytose antigen, we evaluated the acquisition of endocytic function, the expression of uptake receptors and the internalization of soluble and small particulate antigens in neonatal, juvenile and adult mice. Although LC from 4-day-old mice were weakly positive for the mannose-type receptor, Langerin, they were capable of internalizing fluorescein isothiocyanate (FITC)-dextran, but to a lesser extent than LC from 6-week-old mice. However, when ratio data were calculated to account for variations in fluorescence intensity at 4°, it was demonstrated that neonatal LC continued to internalize antigen over a longer period of time than adult mice and, as the ratios were much higher, that neonatal cells were also relatively more efficient in antigen uptake. When receptors for mannan and mannose were competitively blocked, LC from neonatal mice, but not adult mice, could still efficiently internalize FITC,dextran. Consequently, the uptake of FITC,dextran, in part, occurred via alternative receptors or a receptor-independent fluid-phase pathway. A feasible pathway is macropinocytosis, as LC from 4-day-old mice demonstrated a reduction in FITC,dextran internalization by the macropinocytosis inhibitor, wortmannin. Evidence of a functional macropinocytosis pathway in neonatal LC was further supported by internalization of the soluble tracer Lucifer Yellow (LY). We conclude that neonatal LC preferentially utilize a wortmannin-sensitive, fluid-phase pathway, rather than receptor-mediated endocytosis, to internalize antigen. As neonatal LC are capable of sampling their environment without inducing immunity, this may serve to avoid inappropriate immune responses during the neonatal period. [source] Ly6 family member C4.4A binds laminins 1 and 5, associates with galectin-3 and supports cell migrationINTERNATIONAL JOURNAL OF CANCER, Issue 5 2005Claudia Paret Abstract C4.4A is a member of the Ly6 family, with low homology to uPAR. It has been detected mainly on metastasizing carcinoma cells and proposed to be involved in wound healing. So far, C4.4A has been observed as an orphan receptor, and its functional activity has not been explored. Using recombinant rat C4.4A (rrC4.4A) made in a eukaryotic expression system, we demonstrate by immunohistology that C4.4A ligands are strongly expressed in tissues adjacent to squamous epithelia of, e.g., tongue and esophagus, the expression pattern partly overlapping with laminin (LN) and complementing the C4.4A expression that is found predominantly on the basal layers of squamous epithelium. ELISA screening of several components of the extracellular matrix revealed selective binding of rrC4.4A to LN1 and LN5 and that transfection of the BSp73AS tumor line with C4.4A cDNA (BSp73AS-1B1) promoted LN1 and LN5 binding. Binding of BSp73AS-1B1 to LN5 and, less markedly, LN1 induced spreading, lamellipodia formation and migration. C4.4A also associates with galectin-3 in nontransformed tissues and tumor lines. There is evidence that the association of C4.4A with galectin-3 influences LN adhesion. C4.4A was described originally as a metastasis-associated molecule. Our findings that LN1 and LN5 are C4.4A ligands, that galectin-3 associates with C4.4A and that C4.4A ligand binding confers a migratory phenotype are well in line with the supposed metastasis association. © 2005 Wiley-Liss, Inc. [source] Real-time RT-PCR detection of CK19, CK7 and MUC1 mRNA for diagnosis of lymph node micrometastases in non small cell lung carcinomaINTERNATIONAL JOURNAL OF CANCER, Issue 5 2005Pierre Saintigny Abstract Metastatic lymph nodes (LNs) are the major prognostic factor in resected non small cell lung carcinoma (NSCLC). However, almost 50% of pN0 patients relapse, suggesting metastatic cells undetected by current staging procedures. A combination of markers [cytokeratins 19 and 7 (CK19, CK7) and mucin type 1 (MUC1) mRNAs] was therefore evaluated by real-time RT-PCR in order to detect occult cancer cells. Forty-three NSCLC tumor samples, 4 micrometastatic, 6 metastatic and 84 histologically negative mediastinal LNs from 19 patients with NSCLC were evaluated as well as blood mononuclear cells from 29 healthy volunteers and 17 benign LNs. When tested on cell lines, RT-PCR was particularly efficient for evaluation of CK19, CK7 and MUC1 mRNA expression. All tumor samples were positive for at least 1 marker and 74% of samples were positive for all 3 markers. CK7 and CK19 mRNA were not detected in benign LN and blood cells from healthy donors in contrast with MUC1 mRNA. Only CK7 and CK19 mRNA were therefore used for evaluation of mediastinal LNs: the 6 histologically metastatic and the 4 micrometastatic LNs were positive for at least one marker. Among the 84 histologically negative LNs, 6 (7%) were positive for at least one marker, potentially changing the stage of 2 out of 19 patients. In conclusion, in our feasibility study, parallel molecular detection of CK19 and CK7 mRNA can be considered a specific diagnostic tool for the assessment of microscopic lymphatic spread. Its prognostic impact remains to be evaluated in a prospective study. © 2005 Wiley-Liss, Inc. [source] Patterns of convection in the tropical pacific and their influence on New Zealand weatherINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2002John W. Kidson Abstract Characteristic patterns of convection in the tropical Pacific Ocean have previously been inferred from analysis of outgoing longwave radiation (OLR), and associated with year-to-year variations in El Niño (EN),Southern Oscillation events. This study examines both the effects of these convection patterns on the New Zealand climate, and the more general influence of tropical convection on the New Zealand sector of the Southern Hemisphere. The Southern Hemisphere circulation, as a whole, is found to be most strongly influenced by equatorial convection near the Philippines, and in a broad band over the central Pacific. Where increased convection occurs west of 160°E, La Niña-like (LN) conditions prevail. When the anomalous convective activity is located near the dateline, in ,moderate' EN conditions, SW flow prevails over New Zealand. This gives way to stronger WSW anomalies as the centre of convection is displaced further eastwards and a second centre of reduced convection becomes prominent west of the dateline in strong EN (EN+) events. The changes in wind regimes over the New Zealand region implied by the hemispheric 1000 hPa height fields are supported by mean sea-level pressure differences between a number of New Zealand and adjacent island stations. Indices of the zonal flow show a weak reduction in strength of the westerlies for LN OLR composites, and no apparent effects for EN composites, whereas EN+ conditions strongly favour above-normal westerlies. The meridional flow over New Zealand is skewed towards more frequent southerlies in both the EN and EN+ composites, whereas LN conditions favour northerly flow anomalies. A change is also observed in the frequency of New Zealand-area ,weather regimes'. Enhanced convection centred on 5°S and east of the dateline, as found in the EN+ composites, leads to an increase in zonal regimes and a corresponding decrease in blocking regimes. The direct influence of tropical OLR variations on New Zealand temperature and precipitation has also been assessed. These indicate that the response is not simply one of degree. Different spatial anomaly patterns in the climatic elements result from the varying regional circulation patterns, and these need to be considered if present climate-forecasting schemes are to be improved. Copyright © 2002 Royal Meteorological Society. [source] Mortality association of enhanced CD44v6 expression is not mediated through occult lymphatic spread in stage II colorectal cancerJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 9 2000Gerard Clarke Abstract Background and Aims: In the absence of other metastatic disease, the presence of lymph node metastasis remains the most important determinant of survival in colorectal cancer (CRC). Cluster designation 44 variant 6 (CD44v6) over-expression is associated with worse outcome in all stages of CRC. The CD44v6 is believed to confer metastatic potential through its facilitation of migration, extravasation and proliferation, although the specific means by which it conveys an adverse prognosis in CRC is unknown. The aim of the present study was to determine if CD44v6 over-expression in Stage II CRC subjects was associated with the presence of lymph node micrometastases. Methods: We assessed tumour CD44v6 expression in 43 randomly sampled subjects who had resections for Stage II CRC between 1984 and 1991 by using immunohistochemistry. Micrometastases were sought in corresponding lymph node (LN) sections using keratin immunohistochemistry. Results: There was a statistical trend between tumour CD44v6 over-expression and mortality (P = 0.09) and a significant relationship between LN cytokeratins and mortality (P = 0.01). There was no association between the detection of LN cytokeratins and tumour CD44v6 over-expression. Conclusion: We conclude that the adverse survival effect of CD44v6 over-expression is not mediated though lymphatic spread and postulate that it may therefore facilitate haematogenous metastasis. [source] Chronic Ethanol Consumption Decreases Murine Langerhans Cell Numbers and Delays Migration of Langerhans Cells as Well as Dermal Dendritic CellsALCOHOLISM, Issue 4 2008Kristin J. Ness Background:, Chronic alcoholics experience increased incidence and severity of infections, the mechanism of which is incompletely understood. Dendritic cells (DC) migrate from peripheral locations to lymph nodes (LN) to initiate adaptive immunity against infection. Little is known about how chronic alcohol exposure affects skin DC numbers or migration. Methods:, Mice received 20% EtOH in the drinking water for up to 35 weeks. Baseline Langerhans cell (LC) and dermal DC (dDC) numbers were enumerated by immunofluorescence (IF). LC repopulation after inflammation was determined following congenic bone marrow (BM) transplant and ultraviolet (UV) irradiation. Net LC loss from epidermis was determined by IF following TNF-, or CpG stimulation. LC and dDC migration into LN was assessed by flow cytometry following epicutaneous FITC administration. Results:, Chronic EtOH consumption caused a baseline reduction in LC but not dDC numbers. The deficit was not corrected following transplantation with non-EtOH-exposed BM and UV irradiation, supporting the hypothesis that the defect is intrinsic to the skin environment rather than LC precursors. Net loss of LC from epidermis following inflammation was greatly reduced in EtOH-fed mice versus controls. Ethanol consumption for at least 4 weeks led to delayed LC migration into LN, and consumption for at least 8 weeks led to delayed dDC migration into LN following epicutaneous FITC application. Conclusions:, Chronic EtOH consumption causes decreased density of epidermal LC, which likely results in decreased epidermal immunosurveillance. It also results in altered migratory responsiveness and delayed LC and dDC migration into LN, which likely delays activation of adaptive immunity. Decreased LC density at baseline appears to be the result of an alteration in the skin environment rather than an intrinsic LC defect. These findings provide novel mechanisms to at least partially explain why chronic alcoholics are more susceptible to infections, especially those following skin penetration. [source] Meeting the 12 lymph node (LN) benchmark in colon cancer,JOURNAL OF SURGICAL ONCOLOGY, Issue 1 2010A. Rajput MD Abstract Background Examining ,12 LN in colon cancer has been suggested as a quality metric. The purpose of this study was to determine whether the 12 LN benchmark is achieved at NCCN centers compared to a US population-based sample. Methods Patients with stage I,III disease resected at NCCN centers were identified from a prospective database (n,=,718) and were compared to 12,845 stage I,III patients diagnosed in a SEER region. Age, gender, location, stage, number of positive nodes were compared for NCCN and SEER data in regards to number of nodes evaluated. Multivariate logistic regression models were developed to identify factors associated with evaluating 12 LNs. Results 92% of NCCN and 58% of SEER patients had ,12 LN evaluated. For patients treated at NCCN centers, factors associated with not meeting the 12 LN target were left-sided tumors, stage I disease and BMI >30. Conclusions ,12 LN are almost always evaluated in NCCN patients. In contrast, this target is achieved in 58% of SEER patients. With longer follow-up of the NCCN cohort we will be able to link this quality metric to patterns of recurrence and survival and thereby better understand whether increasing the number of nodes evaluated is a priority for cancer control. J. Surg. Oncol. 2010;102:3,9. © 2010 Wiley-Liss, Inc. [source] Assessment of open versus laparoscopy-assisted gastrectomy in lymph node-positive early gastric cancer: A retrospective cohort analysisJOURNAL OF SURGICAL ONCOLOGY, Issue 1 2010Ji Yeong An MD Abstract Background Laparoscopy-assisted gastrectomy (LAG) is still limited for early gastric cancer (EGC) with low possibility of lymph node (LN) metastasis, due to the concern for incomplete LN dissection and controversial long-term outcomes. We assessed oncological outcomes of laparoscopy-assisted versus open gastrectomy (OG) for patients with LN positive EGC. Methods Between 2003 and 2007, 204 patients underwent surgery for LN positive EGC. We evaluated adequacy of LN dissection and early and long-term outcomes after OG (n,=,162) and LAG (n,=,42). Results Operative time was longer but hospital stay was shorter for LAG than OG. Postoperative complications occurred in 14 patients (8.6%) after OG and 1 patient (2.4%) after LAG (P,=,0.316). Mean number of retrieved LNs and number of retrieved and metastatic LNs for each station did not differ between the two groups. During median 35 months of follow-up, 14 patients (8.6%) developed recurrence after OG, compared with 4 patients (9.5%) after LAG (P,=,0.769). Overall 5-year disease-free survival was 89.9% and 89.7% after OG and LAG. Status of LN metastasis was the only independent prognostic factor for disease-free survival. Conclusions LAG is an oncologically safe procedure even for LN positive EGC. Adequate LN dissection and comparable long-term outcomes to OG can be achieved by LAG. J. Surg. Oncol. J. Surg. Oncol. 2010;102:77,81. © 2010 Wiley-Liss, Inc. [source] Improving the quality of processing gastric cancer specimens: The pathologist's perspective,JOURNAL OF SURGICAL ONCOLOGY, Issue 3 2010Alyson L. Mahar BSc Abstract Background and Objectives Research into surgeon and pathologist knowledge of guidelines for lymph node (LN) assessment in gastric cancer demonstrated a knowledge deficit. To understand factors affecting optimal assessment we surveyed pathologists to identify external barriers. Methods Pathologists were identified using two Ontario physician databases and surveyed online or by mail, with a 40% response rate. Results The majority (56%) of pathologists stated assessing an additional five LNs would not be a burden. Most (80%) pathologists disagreed with pay for performance for achieving quality standards. Qualitative analysis determined the majority of pathologists believed achieving quality standards was inherent to their profession and should not require incentives. Poor surgical specimen was identified as a barrier and underscores the importance of aiming quality improvement initiatives at the multidisciplinary team. Conclusion In addition to education, tailoring an intervention to address all barriers, including laboratory constraints may be an effective means of improving gastric cancer care. J. Surg. Oncol. 2010; 101:195,199. © 2010 Wiley-Liss, Inc. [source] Staging of esophageal carcinoma: Length of tumor and number of involved regional lymph nodes.JOURNAL OF SURGICAL ONCOLOGY, Issue 5 2006Are these independent prognostic factors? Abstract Background and Objectives New potential prognostic indicators aside from the TNM classification have been proposed. The aim of this study was to analyze the prognostic relevance of tumor length as well as number of involved regional lymph nodes (LNM) in patients with esophageal carcinoma. Methods Two hundred thirteen patients with esophageal carcinoma (116 squamous cell- and 97 adenocarcinoma) were included in this study. Treatment of choice was subtotal en bloc esophagectomy including "2-field" lymphadenectomy. The median number of examined lymph nodes (LNs) was 28. Eighty patients (38%) received preoperative radio-chemotherapy according to a standardized protocol. Histopathology consisted of tumor stage, residual tumor, grading, and number of examined and involved LN. Univariate and multivariate prognostic values were calculated. Results Length of tumor correlated with pT/ypT-category (P,<,0.01). Univariate but not multivariate analysis showed better survival for tumors ,3 cm (P,<,0.05). Patients with 1,5 LNM had significantly better prognoses than those with more than 5 LNM (Hazard ratio 2.7, 95% CI,=,1.7,4.2) (P,<,0.01). Patients without LNM and more than 15 examined LN showed significantly better prognosis than those with fewer examined LN (Hazard ratio,=,0.3, 95% CI,=,0.1,0.6) (P,<,0.01). Conclusions A revision of the TNM classification for esophageal carcinoma should subdivide the pN1-category according to the number of LNM. J. Surg. Oncol. 2006;94:355,363. © 2006 Wiley-Liss, Inc. 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