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Obvious Changes (obvious + change)
Selected AbstractsLable-Free Electrochemical DNA Sensor Based on Gold Nanoparticles/Poly(neutral red) Modified ElectrodeELECTROANALYSIS, Issue 6 2010Keying Zhang Abstract We present a new strategy for the label-free electrochemical detection of DNA hybridization based on gold nanoparticles (AuNPs)/poly(neutral red) (PNR) modified electrode. Probe oligonucledotides with thiol groups at the 5-end were covalently linked onto the surface of AuNPs/PNR modified electrode via S-Au binding. The hybridization event was monitored by using differential pulse voltammetry (DPV) upon hybridization generates electrochemical changes at the PNR-solution interface. A significant decrease in the peak current was observed upon hybridization of probe with complementary target ssDNA, whereas no obvious change was observed with noncomplementary target ssDNA. And the DNA sensor also showed a high selectivity for detecting one-mismatched and three-mismatched target ssDNA and a high sensitivity for detecting complementary target ssDNA, the detection limit is 4.2×10,12,M for complementary target ssDNA. In addition, the DNA biosensor showed an excellent reproducibility and stability under the DNA-hybridization conditions. [source] Abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea communities of an alkaline sandy loamENVIRONMENTAL MICROBIOLOGY, Issue 6 2008Ju-pei Shen Summary The abundance and composition of soil ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities under different long-term (17 years) fertilization practices were investigated using real-time polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE). A sandy loam with pH (H2O) ranging from 8.3 to 8.7 was sampled in years 2006 and 2007, including seven fertilization treatments of control without fertilizers (CK), those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): NP, NK, PK and NPK, half chemical fertilizers NPK plus half organic manure (1/2OMN) and organic manure (OM). The highest bacterial amoA gene copy numbers were found in those treatments receiving N fertilizer. The archaeal amoA gene copy numbers ranging from 1.54 × 107 to 4.25 × 107 per gram of dry soil were significantly higher than those of bacterial amoA genes, ranging from 1.24 × 105 to 2.79 × 106 per gram of dry soil, which indicated a potential role of AOA in nitrification. Ammonia-oxidizing bacteria abundance had significant correlations with soil pH and potential nitrification rates. Denaturing gradient gel electrophoresis patterns revealed that the fertilization resulted in an obvious change of the AOB community, while no significant change of the AOA community was observed among different treatments. Phylogenetic analysis showed a dominance of Nitrosospira -like sequences, while three bands were affiliated with the Nitrosomonas genus. All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin). These results suggest that long-term fertilization had a significant impact on AOB abundance and composition, while minimal on AOA in the alkaline soil. [source] Courtship in the Zig-Zag Salamander (Plethodon dorsalis): Insights into a Transition in Pheromone-Delivery BehaviorETHOLOGY, Issue 9 2005Amy L. Picard Courtship in plethodontid salamanders includes the delivery of male courtship pheromones by two distinct modes. Within the eastern Plethodon clade of the tribe Plethodontini, members of the Plethodon cinereus species group use an ancestral ,vaccination' mode of delivery, while members of the P. glutinosus group use an olfactory delivery mode. In order to shed light on this transition in delivery mode, I observed courtship behavior in P. dorsalis, a species that is phylogenetically intermediate to the P. cinereus and P. glutinosus groups. My observations indicate that P. dorsalis also is intermediate to the P. cinereus and P. glutinosus species groups in terms of courtship behavior. The context of delivery of male courtship pheromones in P. dorsalis is similar to that of the P. cinereus species group; however, the mode of pheromone delivery in P. dorsalis is olfactory. Thus, a transition in the context of pheromone delivery underlies the more obvious change in pheromone delivery mode. I discuss these findings in terms of the evolution of courtship pheromone delivery across the eastern Plethodon clade. I also report the first observations of ,premature' spermatophore deposition by male plethodontids. [source] Effect of Hydrogen on Fatigue Strength of High-Strength Steels in the VHCF Regime,ADVANCED ENGINEERING MATERIALS, Issue 7 2009Yongde Li Diffusible hydrogen or non-diffusible hydrogen can decrease the fatigue strength of high-strength steels. The hydrogen influence factor f(C) describes the hydrogen damage level of fatigue strength. Fatigue strength decreases with increasing non-diffusible hydrogen content in the range 1 ppm,<,Ci,<,3.0,ppm. Fatigue strength decreases significantly with increasing diffusible hydrogen content in the range 1 ppm,<,Cr,<,3.0,ppm, but shows almost no obvious change in the range 3.0 ppm,<,Cr,<,10.0,ppm. [source] Redistribution of the sheep neonatal Fc receptor in the mammary gland around the time of parturition in ewes and its localization in the small intestine of neonatal lambsIMMUNOLOGY, Issue 3 2002Balázs Mayer Summary Maternal immunity is mediated exclusively by colostral immunoglobulins in ruminants. As the neonatal Fc receptor (FcRn) is suggested to be involved in the transport of immunoglobulin G (IgG) in the mammary gland, we cloned this receptor from sheep and analysed its expression in the mammary gland around the time of parturition and also in the small intestine from the newborn lamb. FcRn heavy-chain mRNA was detected (by using in situ hybridization) exclusively in the acinar and ductal epithelial cells in mammary gland biopsies both before and after parturition. Immunohistochemistry revealed that the cytoplasm of the epithelial cells of the acini and ducts in the mammary gland biopsies stained homogeneously before parturition. A remarkable difference was observed in the pattern after lambing, where the apical side of the cells was strongly stained. The presence of the FcRn in the acinar and ductal epithelial cells of the mammary gland, and the obvious change in distribution before and after parturition, indicate that the FcRn plays an important role in the transport of IgG during colostrum formation in ruminants. Immunohistochemical analysis detected a strong apical and a weak basal FcRn signal in the duodenal crypt cells of a neonatal lamb, which have been previously demonstrated to secrete IgG1 in newborn ruminants. The FcRn was not detected in the duodenal enterocytes, which absorb intact IgG from the colostrum in a non-specific manner. These data suggest that FcRn is involved in IgG1 secretion in ruminant epithelial cells. [source] Photoconductivity of a Single Small-Molecule Organic Nanowire,ADVANCED MATERIALS, Issue 12 2008Xiujuan Zhang The photoconductivity of a methyl squarylium (MeSq) single-nanowire device shows a high light sensitivity, wavelength-dependent photoresponse, good response speed, and excellent stability and reproducibility. Nanodevices fabricated on flexible substrates (see figure) exhibit good mechanical bendability and no obvious change in performance after bending to a curvature of 0.5,cm,1. [source] Fibrocartilage at the entheses of the suprascapular (superior transverse scapular) ligament of man,a ligament spanning two regions of a single boneJOURNAL OF ANATOMY, Issue 5 2001B. MORIGGL The suprascapular ligament converts the suprascapular notch into a foramen separating the vessels and nerve of the same name. It connects 2 regions of the same bone and does not cross any joint, and no mechanical function has yet been attributed to it. Nevertheless, variations in its thickness and length, and its tendency to ossify, suggest that the ligament responds to changes in mechanical load. This should be reflected in the composition of the extracellular matrix. The primary purpose of the present study is to demonstrate that the suprascapular ligament has fibrocartilaginous entheses (i.e. insertion sites), even though there is no obvious change in insertional angle that directly results from joint movement. Such a change is more typical of tendons or ligaments that cross highly mobile joints. The complete ligament (including both entheses) was removed from 7 cadavers shortly after death and fixed in 90% methanol. Cryosections were immunolabelled with a panel of monoclonal antibodies against collagens (types I, II, III, VI), glycosaminoglycans (chondroitin 4 sulphate, chondroitin 6 sulphate, dermatan sulphate and keratan sulphates), proteoglycans (aggrecan and versican) and link protein. Both entheses were strongly fibrocartilaginous, and a moderately fibrocartilaginous matrix was also detected throughout the remainder of the ligament. The extracellular matrix of both entheses labelled strongly for type II collagen, aggrecan and link protein. The fibrocartilaginous character of the entheses suggests that the insertion sites of the ligament are subject to both compressive and tensile loading and are regions of stress concentration. This in turn probably reflects the complex shape of the scapula and the presence of a conspicuous indentation (the suprascapular notch) near the ligament. The loading patterns may reflect either the attachment of muscles and/or the forces transmitted to the suprascapular ligament from the neighbouring coracoclavicular ligament. [source] Reconstitution of Photosystem II Reaction Center with Cu-Chlorophyll aJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 11 2006Shuang Liu Abstract An isolated photosystem (PS) II reaction center (RC) with altered pigment content was obtained by chemical exchange of native chlorophyll a (Chl) with externally added Cu-Chl a (Cu-Chl). Pigment composition and spectroscopic properties of the RC exchanged with Cu-Chl were compared with native RC and RC treated with Chl in the same way. High-performance liquid chromatography analysis showed approximately 0.5 Cu-Chl per two pheophytin in the Cu-Chl-reconstituted RC preparation. Insertion of Cu-Chl resulted in a decrease in absorption at 670 nm and an increase at 660 nm, suggesting that the peripheral Chl may have been displaced. Fluorescence emission spectra of the Cu-Chl-reconstituted RC displayed a marked decrease in fluorescence yield and a blue shift of the band maximum, accompanied by the appearance of a broad peak at a shorter wavelength, indicating that energy transfer in the modified RC was disturbed by Cu-Chl, a quencher of the excited state. However, there were few differences in the circular dichroism (CD) spectra, suggesting that the arrangement of pigments and proteins responsible for the CD signal was not significantly affected. In addition, no obvious change in peptide components was found after the exchange procedure. (Managing editor: Ping He) [source] The p53 molecule and its prognostic role in squamous cell carcinomas of the head and neckJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 9 2000Karin Nylander Abstract: Despite intense research, the 5-year survival rate for patients with squamous cell carcinoma of the head and neck (SCCHN) is still low. Several different factors have been studied in the search for one or more factors that give important prognostic information at the time of diagnosis. Many recent studies have focused on the TP53 tumour suppressor gene, analysing its gene status and protein status. When looking at p53 protein expression, using immunohistochemistry, no correlation to patient outcome has been seen for the whole group of SCCHN. However, a significant association between p53 expression and poor patient outcome was found when looking only at patients with laryngeal squamous cell carcinomas. Also, in oral premalignant lesions, expression of p53-positive cells in the suprabasal layers of the epithelium has been seen as an indication of impending malignant development. Concerning the prognostic significance of mutations in the TP53 gene, results differ. But when restricting analysis to tumours with mutations causing an obvious change in protein, TP53 mutation was found to be a strong and independent variable for prognosticating survival. This review article gives an up-to-date overview of the p53 molecule and evaluates its possible prognostic role in SCCHN. Today it is clear that the p53 pathway is very important in SCCHN biology and potentially in its treatment. The function and importance of a few other cell cycle proteins connected to p53 are also discussed. [source] Size-dependent Raman and infrared studies of PbSe nanoparticlesJOURNAL OF RAMAN SPECTROSCOPY, Issue 9 2008F. S. Manciu Abstract Micro-probe Raman and far-infrared absorption spectroscopies were used to prove the existence of optical phonon modes of PbSe nanoparticles prepared by colloidal chemistry and preliminarily characterized by transmission electron microscopy. To the best of our knowledge, this is the first time that evidence of the surface phonon (SP) mode by Raman spectroscopy has been experimentally observed. The wavenumber of the SP mode is consistent with its prediction by a dielectric continuum model. While for different PbSe nanoparticle sizes the observed SP mode does not show any obvious change in its position, there is a clear shift by approximately 4 cm,1 toward higher wavenumber in the appearance of the LO(,) in the Raman spectra from the 3 nm to the 7 nm PbSe nanoparticles. Far-infrared measurements demonstrate the presence of the transverse optical TO(,) and of the coupled phonon modes. Copyright © 2008 John Wiley & Sons, Ltd. [source] Effect of pulsatile administration of levodopa on dyskinesia induction in drug-naïve MPTP-treated common marmosets: Effect of dose, frequency of administration, and brain exposureMOVEMENT DISORDERS, Issue 5 2003Lance A. Smith MSc Abstract Levodopa (L -dopa) consistently primes basal ganglia for the appearance of dyskinesia in parkinsonian patients and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) -treated primates. This finding may reflect its relatively short duration of effects resulting in pulsatile stimulation of postsynaptic dopamine receptors in the striatum. We have compared the relationship between L -dopa dose and frequency of administration on dyskinesia initiation in drug-naïve, MPTP-treated common marmosets. We have also studied the effect of increased brain exposure to pulsatile administration by combining a low-dose of L -dopa with the peripheral catechol- O -methyltransferase inhibitor (COMT-I), entacapone. Pulsatile administration of a low (dose range, 5.0,7.5 mg/kg p.o.) or a high (12.5 mg/kg) dose of L -dopa plus carbidopa b.i.d. produced a dose-related reversal of motor deficits. Repeated administration of low and high doses of L -dopa for 26 days to drug-naïve, MPTP-treated animals also caused a dose-related induction of peak-dose dyskinesia. Repeated administration of high-dose L -dopa b.i.d. compared to once daily caused a frequency-related improvement of motor symptoms, resulting in a more rapid and initially more intense appearance of peak-dose dyskinesia. Administration of low-dose L -dopa b.i.d. for 26 days in combination with entacapone enhanced the increase in locomotor activity and reversal of disability produced by L -dopa alone, but with no obvious change in duration of L -dopa's effect. However, combining entacapone with L -dopa resulted in the more rapid appearance of dyskinesia, which was initially more severe than occurred with L -dopa alone. Importantly, increasing pulsatile exposure of brain to L -dopa by preventing its peripheral breakdown also increases dyskinesia induction. © 2003 Movement Disorder Society [source] Effect of growth hormone on testicular dysfunction induced by methotrexate in ratsANDROLOGIA, Issue 2 2009H. Serati Nouri Summary Methotrexate (MTX) is a chemotherapeutic agent causing defective oogenesis and spermatogenesis. This study was performed to assess the role of human growth hormone (GH) on testis recovery after treatment with MTX. Forty male Wistar rats were selected and randomly divided into four groups (n = 10): control (vehicle), GH group (0.3 mg kg,1 GH for 28 days, IP), MTX group (MTX 1 mg kg,1 week,1 for 4 weeks, IP) and GH/MTX group (0.3 mg kg,1 GH for 28 day plus 1 mg kg,1 week,1 MTX for 4 weeks, IP). On days 14 and 28, five rats from each group were killed, testes of rats of all groups were removed, spermatozoa were collected from epididymis and then prepared for analysis. MTX caused significant increase in interstitial tissue and capsular thickness and decrease of testicular and body weight (P < 0.05). Moreover, it caused significant decline in seminiferous tubule diameter and epithelium thickness (P < 0.05). There was no obvious change in morphometrical parameters between MTX/GH and control groups. In MTX group, sperm parameters decreased significantly (P < 0.05). Administration of GH plus MTX reduced the effects of MTX on sperm parameters and testosterone concentration. These results suggested that GH had a protective effect on almost all destructive effects caused by MTX in rat testes and thus improved sperm parameters. [source] Color M-Mode Flow Propagation Velocity: Is It Really Preload Independent?ECHOCARDIOGRAPHY, Issue 8 2005Shih-Kai Lin M.D. Objective: This study investigates the change in flow propagation velocity (FPV) in uremic patients who undergo regular hemodialysis (H/D). Materials and Methods: We studied 93 uremic patients (44 men and 49 women; 59 ± 14-years-old) receiving regular hemodialysis. Patients were separated by baseline left ventricular ejection fraction (LVEF): 71 patients with LVEF > 50% (group 1), 13 patients with LVEF 35,50% (group 2), 7 patients with LVEF < 35% (group 3). All patients were in sinus rhythm before H/D. They received complete transthoracic echocardiographic examinations. Flow propagation velocity was measured by color M-mode echocardiography in apical four chambers view. All these parameters were obtained before and after H/D. Paired data were compared. According to different H/D amounts, we viewed the FPV response after H/D in variant baseline LVEF groups. Result: The baseline FPV became lower in patients with low LVEF. After H/D, obvious decrement of FPV occurred in group 1, but there were no obvious changes in groups 2 and 3. In fact, a slight increment of FPV was found in group 3. In patients with baseline LVEF > 50%, FPV after H/D was almost always lower, regardless of H/D amount. But there was different response in patients with baseline LVEF < 50%. Conclusion: Flow propagation velocity is preload independent in patients with LVEF < 50%, but it is preload-dependent in patients with LVEF > 50%. [source] Abnormal Excitability of Hippocampal CA3 Neurons in Noda Epileptic Rat (NER): Alteration of Seizure with AgingEPILEPSIA, Issue 2000Ryosuke Hanaya Purpose: Noda epileptic rat (NER), a mutant found in thc colony of Crj:Wistar rats, spontaneously shows tonic-clonic convulsions approximately once every 30 hours from 8,16 weeks of age. A long-lasting dcpolarization shift accompanied by repetitivc firings are observed in hippocampal CA3 pyramidal neurons of NER with seizures. Using hippocampal slice preparations of NER, the present electrophysiologi- cal study was performed to elucidate whether this abnormal firing in CA3 neurons developed with age and if abnormality of Ca2+ channel was involved. Methods: Hippocampal slices (40Opm) werc prepared from NER and normal Wistar rats (age; 4,29 weeks). A single rectangular pulse stimulus composed of 0.1-ms duration was delivered to the mossy fibers every 5 seconds though a bipolar electrode placed in the granular cell layer of the dentate gyrus. Intracellular recording was made from the CA3 pyramidal cell using a microelectrode containing 3M KCI intracellular recordings. A Ca2+ spike was elicited by applying a depolarizing pulse (InA, 120ms) in the cell through the recording electrode under a blockadc of Na+ and K+ channels using 1 pM tetrodotoxin and I 0mM tctraethylammonium added to the artificial CSF, respectivcly. Nicardipine (I-IOOnM), a Ca2+ channel blocker, was applicd to the bath. Results: Thirty-seven slices from I9 NER and 6 slices from 4 normal Wishe rats were used. There were no obvious changes in the resting membrane potentials of CA3 neurons between NER and Wistar rats tested. When a single stimulus was delivered to the mossy fibers, a long-lasting depolarization shift accompanied by repetitive firings followed by after-hyperpolarization werc also obtained i n hippocampal CA3 neurons of young NER (4,5 weeks of age) before occurrence of any seizurcs, although the depolarization shift in younger NER was shorter than that in NER aged more than 6 weeks. These abnormal firings werc evokcd in 58% and 30% of all CA3 neurons tested in the younger and mature NER (6,1 5 weeks of age), respectively. Furthermore, abnormal firing was not elicited in NER aged after I6 weeks. Agc-matched Wistar rats showed only single action potentials without any depolarization shift with single mossy fiber stimulation. Bath application of nicardipine (IOnM) inhibited this long-lasting depolarization shift and the accompanying repetitive firing followed by afterhypcrpolarization without affecting the first spike induced by mossy fiber stimulations. Furthermore, nicai-dipine (IOnM) inhibited the Ca2+ spikes elicited by applying a depolarizing pulse in the neurons of NER with seizures, although a higher dose (100nM) did not affect those in Wistar rats. Conclusions: These findings indicate that abnormal excitability of the NER CA3 pyramidal neurons is probably due to abnormality in the Ca2+ channcls. The abnorinal excitability was observed in NER at an age when tonic-clonic convulsions were not detected, suggesting that thc hippocampus may probably scrve as an epileptogenic focus in younger NER and the seizure impulses originating i n this area are transinittcd to the new other seizurc foci in mature NER. [source] Effects of soil improvement treatments on bacterial community structure and soil processes in an upland grassland soilFEMS MICROBIOLOGY ECOLOGY, Issue 1 2003Neil D. Gray Abstract Temporal temperature gradient electrophoresis (TTGE) analysis of 16S rRNA gene fragments amplified with primers selective for eubacteria and ,-proteobacterial ammonia-oxidising bacteria (AOB) was used to analyse changes in bacterial and AOB community profiles of an upland pasture following soil improvement treatments (addition of sewage sludge and/or lime). Community structure was compared with changes in activity assessed by laboratory measurements of basal respiration and ammonia oxidation potentials, and with measurements of treatment- and time-related changes in soil characteristics. The predominant bacterial populations had a high degree of similarity under all treatment regimens, which was most pronounced early in the growing season. Most of the differences that occurred between soil samples with time could be accounted for by spatial and temporal variation; however, analysis of variance and cluster analysis of similarities between 16S rDNA TTGE profiles indicated that soil improvement treatments exerted some effect on community structure. Lime application had the greatest influence. The impact of soil improvement treatments on autotrophic ammonia oxidation was significant and sustained, especially in soils which had received sewage sludge and lime treatments in combination. However, despite obvious changes in soil characteristics, e.g. pH and soil nitrogen, increasing heterogeneity in the AOB community structure over time obscured the treatment effects observed at the beginning of the experiment. Nevertheless, time series analysis of AOB TTGE profiles indicated that the AOB community in improved soils was more dynamic than in control soils where populations were found to be relatively stable. These observations suggest that the AOB populations exhibited a degree of functional redundancy. [source] A linearized implicit pseudo-spectral method for some model equations: the regularized long wave equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2003K. Djidjeli Abstract An efficient numerical method is developed for the numerical solution of non-linear wave equations typified by the regularized long wave equation (RLW) and its generalization (GRLW). The method developed uses a pseudo-spectral (Fourier transform) treatment of the space dependence together with a linearized implicit scheme in time. =10pt An important advantage to be gained from the use of this method, is the ability to vary the mesh length, thereby reducing the computational time. Using a linearized stability analysis, it is shown that the proposed method is unconditionally stable. The method is second order in time and all-order in space. The method presented here is for the RLW equation and its generalized form, but it can be implemented to a broad class of non-linear long wave equations (Equation (2)), with obvious changes in the various formulae. Test problems, including the simulation of a single soliton and interaction of solitary waves, are used to validate the method, which is found to be accurate and efficient. The three invariants of the motion are evaluated to determine the conservation properties of the algorithm. Copyright © 2003 John Wiley & Sons, Ltd. [source] Post-partum endomyometritis diagnosis and treatment: A reviewJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 6 2003William J. Ledger Abstract Over the past 80 years, obstetrical treatment strategies devised to control current problems have resulted in the emergence of new types of infection. These, in turn, have caused modifications in diagnostic techniques and treatment specifics. Currently, the two most obvious changes influencing post-partum infection care are shortened post-partum hospital care, and the widespread use of intra-partum antibiotics to prevent early onset Group B streptococcal sepsis in the newborn. In the present review, risk factors for post-partum infection are delineated and strategies for prophylaxis and treatment are given. [source] Structure and Mechanical Properties of Polyurethane/Silica Hybrid CoatingsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005Yongchun Chen Abstract Summary: Polyurethane/silica hybrid coatings were prepared via in situ (IS) or blending (BL) method using different acidic silica sols. The effects of preparation methods, silica types, and content on the structure and mechanical properties of the hybrid coatings were investigated. It was found that there existed two types of silica phases in the hybrid coatings: silica-rich agglomerate and primary silica-rich phase, whose size and compactness depended upon the silica types and the preparation methods. Introducing silica could result in obvious changes in surface free energy, atomic composition, and mechanical properties of the hybrid coatings. Typical SEM image of the fractured surface of hybrids obtained by the in situ method. [source] Expression of brain natriuretic peptide in the rat heart studies during heart growth and in relation to sympathectomyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2004Magnus Hansson Abstract Brain natriuretic peptide (BNP) might be of importance during heart development and is described to be increasingly expressed in congestive heart failure and to affect the progress of this condition. However, details in the normal expression of BNP are still unclear in various parts of the adult and growing heart, including the conduction system. In this study, we investigated the expression of BNP in relation to that of atrial natriuretic peptide (ANP) in the growing as well as in the adult rat heart. The effects of chemical sympathectomy in adult rats were also examined. Contrary to previous BNP immunohistochemical studies, the BNP antiserum was preabsorbed with an excess of ANP before staining to abolish the crossreactivity with ANP. There was a pronounced BNP immunoreaction in the auricles, the trabeculated ventricular walls, and the peripheral parts of the conduction system at 0,1 days postnatally. The degree of immunoreaction gradually decreased with increasing age. A similar developmental pattern was seen concerning ANP expression, but the magnitude of the latter clearly exceeded that for BNP. Immunoreaction for BNP was never detected in the atrioventricular (AV) node and AV bundle at any stage. In contrast to the situation for ANP previously observed, no obvious changes in BNP immunoreaction patterns were observed in response to sympathectomy. This is the first study to thoroughly demonstrate the expression of BNP in the various regions of the rat heart during growth and in the normal and sympathectomized adult stage. The observations are related to possible functions of natriuretic peptides in the growing and adult heart. Microsc. Res. Tech. 64:30,42, 2004. © 2004 Wiley-Liss, Inc. [source] The sodium-calcium exchanger is a mechanosensitive transporterTHE JOURNAL OF PHYSIOLOGY, Issue 6 2008John P. Reeves This report describes the influence of fluid flow and osmotically induced volume changes on Na+,Ca2+ exchange (NCX) activity in transfected CHO cells. Exchange activity was measured as Na+ -dependent Ca2+ or Ba2+ fluxes using the fluorescent probe fura-2. When exchange activity was initiated by superfusing Ba2+ -containing solutions over the cells for a 20 s interval, a high rate of Ba2+ uptake was observed while the solution was being applied but the rate of Ba2+ uptake declined > 10-fold when the solution flow ceased. Ba2+ efflux in exchange for extracellular Na+ or Ca2+ (Ba2+,Ca2+ exchange) was similarly biphasic. During NCX-mediated Ca2+ uptake, a rapid increase in cytosolic [Ca2+] to a peak value occurred, followed by a decline in [Ca2+]i to a lower steady-state value after solution flow ceased. When NCX activity was initiated by an alternate procedure that minimized the duration of solution flow, the rapid phase of Ba2+ influx was greatly reduced in magnitude and Ca2+ uptake became nearly monophasic. Solution superfusion did not produce any obvious changes in cell shape or volume. NCX-mediated Ba2+ and Ca2+ influx were also sensitive to osmotically induced changes in cell volume. NCX activity was stimulated in hypotonic media and inhibited in hypertonic media; the osmotically induced changes in activity occurred within seconds and were rapidly reversible. We conclude that NCX activity is modulated by both solution flow and osmotically induced volume changes. [source] Vasomotor sympathetic neural control is maintained during sustained upright posture in humansTHE JOURNAL OF PHYSIOLOGY, Issue 2 2006Qi Fu Vasomotor sympathetic activity plays an important role in arterial pressure maintenance via the baroreflex during acute orthostasis in humans. If orthostasis is prolonged, blood pressure may be supported additionally by humoral factors with a possible reduction in sympathetic baroreflex sensitivity. We tested the hypothesis that baroreflex control of muscle sympathetic nerve activity (MSNA) decreases during prolonged upright posture. MSNA and haemodynamics were measured supine and during 45 min 60 deg upright tilt in 13 healthy individuals. Sympathetic baroreflex sensitivity was quantified using the slope of the linear correlation between MSNA and diastolic pressure during spontaneous breathing. It was further assessed as the relationship between MSNA and stroke volume, with stroke volume derived from cardiac output (C2H2 rebreathing) and heart rate. Total peripheral resistance was calculated from mean arterial pressure and cardiac output. We found that MSNA increased from supine to upright (17 ± 8 (s.d.) versus 38 ± 12 bursts min,1; P < 0.01), and continued to increase to a smaller degree during sustained tilt (39 ± 11, 41 ± 12, 43 ± 13 and 46 ± 15 bursts min,1 after 10, 20, 30 and 45 min of tilt; between treatments P < 0.01). Sympathetic baroreflex sensitivity increased from supine to upright (,292 ± 180 versus,718 ± 362 units beat,1 mmHg,1; P < 0.01), but remained unchanged as tilting continued (,611 ± 342 and ,521 ± 221 units beat,1 mmHg,1 after 20 and 45 min of tilt; P= 0.49). For each subject, changes in MSNA were associated with changes in stroke volume (r= 0.88 ± 0.13, P < 0.05), while total peripheral resistance was related to MSNA during 45 min upright tilt (r= 0.82 ± 0.15, P < 0.05). These results suggest that the vasoconstriction initiated by sympathetic adrenergic nerves is maintained by ongoing sympathetic activation during sustained (i.e. 45 min) orthostasis without obvious changes in vasomotor sympathetic neural control. [source] Intra-specific effects of sea cucumber (Apostichopus japonicus) with reference to stocking density and body sizeAQUACULTURE RESEARCH, Issue 8 2010Shuanglin Dong Abstract The present studies deal with the intra-specific effects of sea cucumber Apostichopus japonicus with unlimited food resources, especially the effects of stocking density on growth variation of the animal and energetic changes of small individuals under the stress of large individuals. The results showed that with the initial body weight of 5.12±0.09,6.11±0.26 g of sea cucumber among the densities of 5, 10, 20, 30, 40 and 50 ind./100 L, the density of 20 ind./100 L was the optimum stocking density because of its highest specific growth rate, crude protein content and crude lipid content in tissue. Individual growth variation of A. japonicus increased with the increase of stocking densities, whereas no significant differences in variation were found when the density was over 30 ind./100 L (P>0.05). The low-weight individuals under the stress of heavy-weight individuals exhibited obvious changes in energetics, such as lower ingestion rate, lower energy deposited as growth but higher respiration and excretion. The coefficient of variation in growth of the animals was over 70% due to the simultaneous action of aggression and maybe a factor of chemical mediator, and led to significant changes in the energetics of small-sized individuals. [source] Study on surface morphology and selectivity of precipitated iron catalysts of FTSASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Wang Xingjun Abstract The precipitated iron catalyst was prepared by co-precipitation. The surface morphology of the catalyst was investigated under different reduction conditions by SEM (S-250, USA). Under H2 -reduction, the surface morphology of the catalyst had the obvious changes, which the diameter reduced, adhered together, came into being wads considered as a group. But the surface morphology of the catalyst had almost no change under CO reduction. The crystal structure of the catalyst was studied under different reduction conditions by X-ray diffraction (XRD) (Rigaku D/max, Japanese). It was found that the catalyst was reduced completely with H2, but it was reduced partly with CO. The crystal structure of the catalyst converted into the metallic phase with H2 reduction. However, most of the iron converted into iron oxide (Fe3O4) with CO reduction. And the predominant phase in a sample of a mature catalyst is ,-Fe5C2, which is the active phase in the Fischer-Tropsch synthesis (FTS). The experimental results showed that CO conversion and H2 conversion increase with the change of reaction temperature from 260 to 300 °C, under the conditions of pressure P = 2.6 MPa, space velocity = 0.86 Nl h,1 g-Fe,1, n(H2)/n(CO) = 2/3, and most of the hydrocarbon products are C5,11 which hold half of the hydrocarbon products. The next content is C2,4 which holds the quarter of hydrocarbon products. Then it is C12+, which is equal to 18%. And the last is C1, which is equal to 7%. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Detrital zircon geochronology and its provenance implications: responses to Jurassic through Neogene basin-range interactions along northern margin of the Tarim Basin, Northwest ChinaBASIN RESEARCH, Issue 1 2010Zhong Li ABSTRACT Previously published research from the Kuqa Subbasin along northern margin of the Tarim Basin shows five tectonic-depositional phases from Triassic to Neogene time. In order to reveal additional detailed information on the nature of provenance terrains and tectonic attributes since late Mesozoic time, five typical sandstone samples from Jurassic,Neogene strata were collected for U,Pb dating of detrital zircons. Geochronological constitution of detrital zircons of the Middle Jurassic sample is essentially unimodal and indicates major contributions from the South Tian Shan even Yili,Central Tian Shan, wherein most 370,450 Ma zircons probably resulted from tectonic accretion events between the Yili,Central Tian Shan block and South Tian Shan Ocean during Silurian and Devonian time, with sandstone provenance tectonic attributes of passive continental margin. The Lower Cretaceous sample shows a complicated provenance detrital zircon signature, with new peak ages of 290,330 Ma as well as 370(or 350),450 Ma showing evident arc orogenic provenance tectonic attribute, probably reflecting a new provenance supply that resulted from denudation process whthin the South Tian Shan and South Tian Shan suture. There are no obvious changes within age probability spectra of detrital zircons between the Cretaceous and early Paleogene samples, which suggests that similar provenance types and basin-range framework continued from Cretaceous to Early Paleogene time. However, unlike the Cretaceous and early Paleogene samples, an age spectra of the Miocene sample is relatively unimodal and similar to that of the Pliocene sample, with peak ages ranging between ,392 and ,458 Ma older than the comparable provenance ages (peak ages about 370,450 Ma) of the Middle Jurassic and Lower Cretaceous samples. Therefore, we conclude that the South Tian Shan was rapidly exhumated and the southern South Tian Shan had become the main source of clastics for the Kuqa Subbasin since the Miocene epoch. [source] The absence of apoeccrine glands in the human axilla has disease pathogenetic implications, including axillary hyperhidrosisBRITISH JOURNAL OF DERMATOLOGY, Issue 6 2007D.L. Bovell Summary Background, The existence of a third type of sweat gland in human axillary skin, the apoeccrine gland, with a capacity to produce much higher sweat output than the eccrine gland, was proposed from examination of microdissected glands. However, previous studies of axillary skin glands did not examine the entire individual glandular structure via serial sections and the markers used to identify the different glands gave conflicting results and, hence, the existence of the apoeccrine gland remains controversial. Objectives, To investigate human axillary sweat glands by serial section histology and immunofluorescence. Methods, Human axillary sweat glands were investigated by serial sectioning of paraffin wax-embedded skin samples taken by biopsy from four male and six female volunteers (age range 20,35 years). Sections were examined by light microscopy and immunofluorescence, using antibodies to antigens reported to be markers for discriminating between eccrine and apocrine gland cells: CD15, CD44, S100 and human milk fat globulin. Results, Light microscopy demonstrated that there were hair follicles and a mean ± SD of 76 ± 14 sweat glands cm,2. Eccrine and apocrine glands were found to be present; however, no glands resembling the apoeccrine glands were detected. Both types of sweat gland exhibited signs of being active, with segments of the secretory coils displaying flattened cells and dilated glandular lumina; however, this dilation did not extend to obvious changes in the width of the gland. None of the eccrine glands exhibited evidence of the presence of apocrine cells or vice versa. Immunofluorescence markers were found not to be specific and did not discriminate between the different types of glands or demonstrate the presence of apoeccrine glands. Conclusions, This is the first time that serial sections of axillary skin have been examined by histology and immunofluorescence. The markers reported to discriminate between apocrine and eccrine glands were found to be nonspecific. No evidence of apoeccrine glands was found either by histology or by immunofluorescence. [source] | ||||||||||||||||||||||