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Sample records for biphasic positive effect

  1. Acute Biphasic Effects of Ayahuasca.

    PubMed

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  2. Acute Biphasic Effects of Ayahuasca

    PubMed Central

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D.; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A.; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8–13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca’s chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered. PMID:26421727

  3. Biphasic effects of losartan potassium on immobility in mice.

    PubMed

    Vijayapandi, Pandi; Nagappa, Anantha Naik

    2005-08-01

    The effects of losartan potassium, an angiotensin AT(1) receptor blocker on immobility in forced swim test have been studied. Effect of losartan potassium, nortriptyline HCl, fluoxetine HCl and reserpine per se and in combination on forced swimming-induced immobility in mice have also been studied. In mice, losartan potassium elicits biphasic responses i.e. positive responses at lower doses (0.1, 1.0 and 5 mg/kg, i.p.) in the forced swim test, a test of potential antidepressant activity and vice versa at higher dose (20 and 100 mg/kg, i.p.). In chronic studies, enhancement in immobility was observed for losartan potassium (3 and 30 mg/kg, p.o., 21 days). In acute combination studies, losartan potassium (1 and 5 mg/kg) significantly reversed the reserpine-induced immobility, but vice versa at 100 mg/kg. Losartan potassium (0.1 and 5 mg/kg) potentiate antidepressant activity of nortriptyline (30 mg/kg, i.p.) in mice, but vice versa at 100 mg/kg. Likewise, Losartan potassium (100 mg/kg), significantly reversed antidepressant activity of fluoxetine HCl, but at 0.1 and 5 mg/kg, failed to modify fluoxetine HCl induced immobility. The obtained biphasic effect of losartan potassium on immobility in mice might be due to inhibitory effect on AT(1) receptor at lower dose and pronounced effect on AT(2) receptor at higher dose (large concentrations of losartan potassium can displace Angiotensin II (Ang II) from its AT(1) receptor to AT(2) receptor.

  4. Biphasic effect of linoleic acid on connexin 46 hemichannels

    PubMed Central

    Evangelista-Martínez, Flavio; León-Paravic, Carmen G.; Altenberg, Guillermo A.; Reuss, Luis

    2011-01-01

    Connexins form hemichannels at undocked plasma membranes and gap-junction channels (GJCs) at intercellular contacting zones. Under physiological conditions, hemichannels have low open probabilities, but their activation under pathological conditions, such as ischemia, induces and/or accelerates cell death. Connexin 46 (Cx46) is a major connexin of the lens, and mutations of this connexin induce cataracts. Here, we report the effects of linoleic acid (LA) on the electrical properties of Cx46 GJCs and hemichannels expressed in Xenopus laevis oocytes. LA has a biphasic effect, increasing hemichannel current at 0.1 μM and decreasing it at concentrations of 100 μM or higher. The effects of extracellular and microinjected LA conjugated to coenzyme A (LA-CoA) suggest that the current activation site is accessible from the intracellular but not extracellular compartment, whereas the current inhibitory site is either located in a region of the hemichannel pore inaccessible to intracellular LA-CoA, or requires crossing of LA through an organelle membrane. Experiments with other fatty acids demonstrated that the block of hemichannels depends on the presence of a hydrogenated double bond at position 9 and is directly proportional to the number of double bonds. Experiments in paired oocytes expressing Cx46 showed that LA does not affect GJCs. The block by unsaturated fatty acids reported here opens the possibility that increases in the concentration of these lipids in the lens induce cataract formation by blocking Cx46 hemichannels. PMID:21360038

  5. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    PubMed Central

    George, Lovya; Jain, Sunil K.

    2015-01-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  6. Biphasic cardiovascular and respiratory effects induced by β-citronellol.

    PubMed

    Ribeiro-Filho, Helder Veras; de Souza Silva, Camila Meirelles; de Siqueira, Rodrigo JoséBezerra; Lahlou, Saad; dos Santos, Armênio Aguiar; Magalhães, Pedro Jorge Caldas

    2016-03-15

    β-Citronellol is a monoterpene found in the essential oil of various plants with antihypertensive properties. In fact, β-citronellol possesses hypotensive actions due to its vasodilator abilities. Here we aimed to show that β-citronellol recruits airway sensory neural circuitry to evoke cardiorespiratory effects. In anesthetized rats, intravenous injection of β-citronellol caused biphasic hypotension, bradycardia and apnea. Bilateral vagotomy, perivagal capsaicin treatment or injection into the left ventricle abolished first rapid phase (named P1) but not delayed phase P2 of the β-citronellol effects. P1 persisted after pretreatment with capsazepine, ondansetron, HC-030031 or suramin. Suramin abolished P2 of apnea. In awake rats, β-citronellol induced biphasic hypotension and bradycardia being P1 abolished by methylatropine. In vitro, β-citronellol inhibited spontaneous or electrically-evoked contractions of rat isolated right or left atrium, respectively, and fully relaxed sustained contractions of phenylephrine in mesenteric artery rings. In conclusion, chemosensitive pulmonary vagal afferent fibers appear to mediate the cardiovascular and respiratory effects of β-citronellol. The transduction mechanism in P1 seems not to involve the activation of transient receptor potential vanilloid subtype 1 (TRPV1), transient receptor potential ankyrin subtype 1 (TRPA1), purinergic (P2X) or 5-HT3 receptors located on airways sensory nerves. P2 of hypotension and bradycardia seems resulting from a cardioinhibitory and vasodilatory effect of β-citronellol and the apnea from a purinergic signaling.

  7. Clinical review: Biphasic positive airway pressure and airway pressure release ventilation

    PubMed Central

    Putensen, Christian; Wrigge, Hermann

    2004-01-01

    This review focuses on mechanical ventilation strategies that allow unsupported spontaneous breathing activity in any phase of the ventilatory cycle. By allowing patients with the acute respiratory distress syndrome to breathe spontaneously, one can expect improvements in gas exchange and systemic blood flow, based on findings from both experimental and clinical trials. In addition, by increasing end-expiratory lung volume, as occurs when using biphasic positive airway pressure or airway pressure release ventilation, recruitment of collapsed or consolidated lung is likely to occur, especially in juxtadiaphragmatic lung legions. Traditional approaches to mechanical ventilatory support of patients with acute respiratory distress syndrome require adaptation of the patient to the mechanical ventilator using heavy sedation and even muscle relaxation. Recent investigations have questioned the utility of sedation, muscle paralysis and mechanical control of ventilation. Furthermore, evidence exists that lowering sedation levels will decrease the duration of mechanical ventilatory support, length of stay in the intensive care unit, and overall costs of hospitalization. Based on currently available data, we suggest considering the use of techniques of mechanical ventilatory support that maintain, rather than suppress, spontaneous ventilatory effort, especially in patients with severe pulmonary dysfunction. PMID:15566621

  8. Rigorous kinetic model considering positional specificity of lipase for enzymatic stepwise hydrolysis of triolein in biphasic oil-water system.

    PubMed

    Hermansyah, Heri; Wijanarko, Anondho; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2010-09-01

    A rigorous kinetic model describing the stepwise triglyceride hydrolysis at the oil-water interface, based on the Ping Pong Bi Bi mechanism using suspended lipase having positional specificity, was constructed. The preference of the enzyme to cleave to the ester bonds at the edge and the center of the glycerol backbone of the substrates (tri-, di- or monoglyceride) was incorporated in the model. This model was applied to the experimental results for triolein hydrolysis using suspended Porcine pancreatic lipase (an sn-1,3 specific lipase) and Candida rugosa lipase (a non-specific lipase) in a biphasic oil-water system under various operating conditions. In order to discuss the model's advantages, other models that do not consider the positional specificity of the lipase were also applied to our experimental results. The model considering the positional specificity of the lipase gave results which fit better with the experimental data and described the effect of the initial enzyme concentration, the interfacial area, and the initial concentrations of triolein on the entire process of the stepwise triolein hydrolysis. This model also gives a good representation of the rate for cleaving the respective ester bonds of each substrate by each type of lipase.

  9. Biphasic effect of bimoclomol on calcium handling in mammalian ventricular myocardium

    PubMed Central

    Nánási, Péter P; Sárközi, Sándor; Szigeti, Gyula; Jóna, István; Szegedi, Csaba; Szabó, Ágnes; Bányász, Tamás; Magyar, János; Szigligeti, Péter; Körtvély, Ágnes; Csernoch, László; Kovács, László; Jednákovits, Andrea

    2000-01-01

    Concentration-dependent effects of bimoclomol, the novel heat shock protein coinducer, on intracellular calcium transients and contractility were studied in Langendorff-perfused guinea-pig hearts loaded with the fluorescent calcium indicator dye Fura-2. Bimoclomol had a biphasic effect on contractility: both peak left ventricular pressure and the rate of force development significantly increased at a concentration of 10 nM or higher. The maximal effect was observed between 0.1 and 1 μM, and the positive inotropic action disappeared by further increasing the concentration of bimoclomol. The drug increased systolic calcium concentration with a similar concentration-dependence. In contrast, diastolic calcium concentration increased monotonically in the presence of bimoclomol. Thus low concentrations of the drug (10–100 nM) increased, whereas high concentrations (10 μM) decreased the amplitude of intracellular calcium transients.Effects of bimoclomol on action potential configuration was studied in isolated canine ventricular myocytes. Action potential duration was increased at low (10 nM), unaffected at intermediate (0.1–1 μM) and decreased at high (10–100 μM) concentrations of the drug.In single canine sarcoplasmic calcium release channels (ryanodine receptor), incorporated into artificial lipid bilayer, bimoclomol significantly increased the open probability of the channel in the concentration range of 1–10 μM. The increased open probability was associated with increased mean open time. The effect of bimoclomol was again biphasic: the open probability decreased below the control level in the presence of 1 mM bimoclomol.Bimoclomol (10 μM–1 mM) had no significant effect on the rate of calcium uptake into sarcoplasmic reticulum vesicles of the dog, indicating that in vivo calcium reuptake might not substantially be affected by the drug.In conclusion, the positive inotropic action of bimoclomol is likely due to the activation of the

  10. An effective biphase system accelerates hesperidinase-catalyzed conversion of rutin to isoquercitrin

    PubMed Central

    Wang, Jun; Gong, An; Yang, Cai-Feng; Bao, Qi; Shi, Xin-Yi; Han, Bei-Bei; Wu, Xiang-Yang; Wu, Fu-An

    2015-01-01

    Isoquercitrin is a rare, natural ingredient with several biological activities that is a key precursor for the synthesis of enzymatically modified isoquercitrin (EMIQ). The enzymatic production of isoquercitrin from rutin catalyzed by hesperidinase is feasible; however, the bioprocess is hindered by low substrate concentration and a long reaction time. Thus, a novel biphase system consisting of [Bmim][BF4]:glycine-sodium hydroxide (pH 9) (10:90, v/v) and glyceryl triacetate (1:1, v/v) was initially established for isoquercitrin production. The biotransformation product was identified using liquid chromatography-mass spectrometry, and the bonding mechanism of the enzyme and substrate was inferred using circular dichroism spectra and kinetic parameters. The highest rutin conversion of 99.5% and isoquercitrin yield of 93.9% were obtained after 3 h. The reaction route is environmentally benign and mild, and the biphase system could be reused. The substrate concentration was increased 2.6-fold, the reaction time was reduced to three tenths the original time. The three-dimensional structure of hesperidinase was changed in the biphase system, which α-helix and random content were reduced and β-sheet content was increased. Thus, the developed biphase system can effectively strengthen the hesperidinase-catalyzed synthesis of isoquercitrin with high yield. PMID:25731802

  11. The effect of collagen fibril orientation on the biphasic mechanics of articular cartilage.

    PubMed

    Meng, Qingen; An, Shuqiang; Damion, Robin A; Jin, Zhongmin; Wilcox, Ruth; Fisher, John; Jones, Alison

    2017-01-01

    The highly inhomogeneous distribution of collagen fibrils may have important effects on the biphasic mechanics of articular cartilage. However, the effect of the inhomogeneity of collagen fibrils has mainly been investigated using simplified three-layered models, which may have underestimated the effect of collagen fibrils by neglecting their realistic orientation. The aim of this study was to investigate the effect of the realistic orientation of collagen fibrils on the biphasic mechanics of articular cartilage. Five biphasic material models, each of which included a different level of complexity of fibril reinforcement, were solved using two different finite element software packages (Abaqus and FEBio). Model 1 considered the realistic orientation of fibrils, which was derived from diffusion tensor magnetic resonance images. The simplified three-layered orientation was used for Model 2. Models 3-5 were three control models. The realistic collagen orientations obtained in this study were consistent with the literature. Results from the two finite element implementations were in agreement for each of the conditions modelled. The comparison between the control models confirmed some functions of collagen fibrils. The comparison between Models 1 and 2 showed that the widely-used three-layered inhomogeneous model can produce similar fluid load support to the model including the realistic fibril orientation; however, an accurate prediction of the other mechanical parameters requires the inclusion of the realistic orientation of collagen fibrils.

  12. Decitabine has a biphasic effect on natural killer cell viability, phenotype, and function under proliferative conditions.

    PubMed

    Kopp, Lisa M; Ray, Anish; Denman, Cecele J; Senyukov, Vladimir S; Somanchi, Srinivas S; Zhu, Shiguo; Lee, Dean A

    2013-07-01

    receptor NKp44, but also causes decreased viability, proliferation, and expression of the activating receptor NKG2D. Decitabine treatment results in a biphasic effect in overall NK cell lytic function, which correlates with a biphasic pattern of global hypomethylation. Decitabine affects the expression of activating and inhibitory receptors in NK cells at low concentrations when exposed during cell proliferation. High doses of decitabine decrease NK cell proliferation and viability, likely through direct inhibition of mRNA transcription. The results of these combined effects leads to a biphasic response in hypomethylation and cytotoxicity. This suggests that optimal immunomodulation with decitabine occurs at low dose ranges and that high doses abrogate this effect through inhibition of proliferation and direct toxicity to NK cells.

  13. Effect of nanostructure on osteoinduction of porous biphasic calcium phosphate ceramics.

    PubMed

    Li, Bo; Liao, Xiaoling; Zheng, Li; Zhu, Xiangdong; Wang, Zhe; Fan, Hongsong; Zhang, Xingdong

    2012-10-01

    In order to evaluate the effect of the nanostructure of calcium phosphate ceramics on osteoinductive potential, porous biphasic calcium phosphate (BCP) ceramics with a nano- or submicron structure were prepared via microwave sintering and compared to conventional BCP ceramics. The selective protein adsorption of bovine serum albumin and lysozyme (LSZ) and the osteogenic differentiation of human mesenchymal stem cells in vitro was investigated. Porous BCP nanoceramics showed higher ability to adsorb proteins, especially low molecular weight protein of LSZ, than conventional BCP ceramics, and the BCP nanoceramics promoted bone sialoprotein expression more than conventional BCP did. Further in vivo study to investigate ectopic bone formation and bone repair efficiency proved the highly osteoinductive potential of nanostructured BCP ceramics. The results suggest that nanostructured BCP ceramics have the potential to become a new generation of bioceramics for bone tissue engineering grafts.

  14. In vitro Biphasic Effect of Honey Bee Venom on Basophils from Screened Healthy Blood Donors

    PubMed Central

    Zanoni, Giovanna; Ortolani, Riccardo; Vella, Antonio

    2011-01-01

    Apis mellifera L. bee venom is the most studied hymenoptera allergen, but many aspects of its action on human basophils remain unclear. Allergologists seek evidence of the effectiveness of bee venom immunotherapy as this approach is the chosen treatment for systemic allergic reactions. The effect of bee venom on human basophils in vitro has not been studied in detail for many reasons, including the paucity of basophils in peripheral blood, inter-individual basophil response variability, and the reliability and predictability of basophil activation tests. We conducted a brief preliminary survey of the effect of Apis bee venom on healthy asymptomatic (non-allergic) subjects. A dose of an aqueous commercial extract of Apis bee venom as high as 10 µg/mL activated resting basophils (CD63=+80-90%, CD203c=+30%), while it inhibited the expression of CD63 (-50%) following basophil stimulation by the soluble agonists formyl-Met-Leu-Phe or anti-IgE. The activation of resting basophils appeared to be dose-related. Only when basophils were activated with an IgE-mediated agonist, did bee venom extract exhibit a possible priming mechanism at the lowest doses used only via CD63, while it was ineffective via CD203c. Autocrine interleukin-3 may play a role in the observed biphasic behavior. PMID:21217927

  15. Biphasic effects of acetylstrophanthidin on automaticity in guinea pig ventricular muscle.

    PubMed

    Karagueuzian, H S; Katzung, B G

    1982-04-23

    The effects of acetylstrophanthidin (AS) on depolarization-induced automaticity and contractility of guinea pig papillary muscle were studied in a single sucrose gap chamber with microelectrode and current-clamp techniques. The concentration used, 1.4-1.8 microM, never induced automaticity in preparations at their normal resting potential. Twenty min after superfusion with AS, action potential duration (APD) was prolonged and the force of contraction increased. These were associated with an increase in slope of phase 4 depolarization and an increase in the membrane resistance (Rm) of muscles depolarized with small constant current pulses. With longer (50-80 min) periods of AS superfusion, APD became shorter, Rm decreased to less than predrug values, and in depolarized preparations, the slope of phase 4 decreased. Contractility remained unchanged throughout this second phase. All of these effects were fully reversible upon 60 min of superfusion with AS-free Tyrode solution. We suggest that the biphasic effects of AS on the automaticity of depolarized ventricular muscle cells are caused by an initial decrease followed by a later increase in transmembrane potassium conductance.

  16. Comb polymer architecture and particle size effects on the behavior of biphasic nanoparticle inks for direct-write assembly

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Jun

    Biphasic nanoparticle mixtures composed of attractive and repulsive colloidal species enable the direct-write assembly of 3D structures with much finer features than those produced by pure colloidal gels. These mixtures rely on the use of comb polymer dispersants to render one particle population stable, while the other population is attractive. In this thesis, we systematically investigate the effects of comb polymer architecture and particle size ratio on the behavior of biphasic nanoparticle inks with the overarching aim of further advancing the direct-write assembly of 3D colloidal structures. We first investigated the effects of both pure polyelectrolytes, poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA), and comb polymer dispersants composed of a PMAA backbone with methoxy-poly(ethylene oxide) (mPEO) teeth of varying molecular weights on the stability of barium titanate (BaTiO 3) suspensions. While each dispersant imparts stability to BaTiO 3 nanoparticles at low ionic strength (< 0.01 M), only the PMAA-mPEO comb polymer with the longest teeth (MWteeth = 2000) provides stability at higher ionic strengths over a broad range of particle sizes and counterion valencies. These results provide guidelines for tailoring the molecular architecture and functionality of comb polymer dispersants for optimal stabilization of the repulsive particle population within the biphasic inks. Next, particle size effects on the rheological properties of biphasic nanoparticle suspensions are studied. Shear elastic modulus, shear yield stress, and compressive yield stress are measured for mixtures of varying total volume fraction, attractive-to-repulsive volume fraction, and particle size ratio between attractive and repulsive species. Our observations indicate that the repulsive particles hinder the formation of the attractive gel network. The time required for shear elastic modulus to approach a steady-state value increases with the fraction of repulsive species

  17. Biphasic effect of Syzygium aromaticum flower bud on reproductive physiology of male mice.

    PubMed

    Mishra, R K; Singh, S K

    2016-11-01

    The flower buds of Syzygium aromaticum (clove) have been used for the treatment of male sexual disorders in indigenous medicines of Indian subcontinent. Therefore to evaluate the efficacy of Syzygium aromaticum on the male reproductive health, chronic oral exposure of aqueous extract of flower buds of Syzygium in three doses (15 mg, 30 mg and 60 mg kg(-1) BW) were studied for a single spermatogenic cycle (35 days) in Parkes (P) strain mice. Lower dose (15 mg) of Syzygium aromaticum flower buds increased serum testosterone level and testicular hydroxysteroid dehydrogenase (HSD) activities and improved sperm motility, sperm morphology, secretory activity of epididymis and seminal vesicle, and number of litters per female. On the other hand, higher doses (30 and 60 mg) of the treatment adversely affected above parameters. Further, higher doses of the extract also had adverse effects on daily sperm production, 1C cell population and on histology of testis. In conclusion, Syzygium aromaticum flower buds extract exhibits biphasic effect on reproductive physiology of male mice. Lower dose of Syzygium aromaticum flower bud extract is androgenic in nature and may have a viable future as an indigenous sexual rejuvenator, while higher doses adversely affected functional physiology of reproductive organs.

  18. Biphasic effect of falcarinol on caco-2 cell proliferation, DNA damage, and apoptosis.

    PubMed

    Young, Jette F; Duthie, Susan J; Milne, Lesley; Christensen, Lars P; Duthie, Garry G; Bestwick, Charles S

    2007-02-07

    The polyacetylene falcarinol, isolated from carrots, has been shown to be protective against chemically induced colon cancer development in rats, but the mechanisms are not fully understood. In this study CaCo-2 cells were exposed to falcarinol (0.5-100 microM) and the effects on proliferation, DNA damage, and apoptosis investigated. Low-dose falcarinol exposure (0.5-10 microM) decreased expression of the apoptosis indicator caspase-3 concomitantly with decreased basal DNA strand breakage. Cell proliferation was increased (1-10 microM), whereas cellular attachment was unaffected by <10 microM falcarinol. At concentrations above 20 microM falcarinol, proliferation of CaCo-2 cells decreased and the number of cells expressing active caspase-3 increased simultaneously with increased cell detachment. Furthermore, DNA single-strand breakage was significantly increased at concentrations above 10 microM falcarinol. Thus, the effects of falcarinol on CaCo-2 cells appear to be biphasic, inducing pro-proliferative and apoptotic characteristics at low and high concentrations of falcarinol, respectively.

  19. Biphasic Effect of Phyllanthus emblica L. Extract on NSAID-Induced Ulcer: An Antioxidative Trail Weaved with Immunomodulatory Effect.

    PubMed

    Chatterjee, Ananya; Chattopadhyay, Subrata; Bandyopadhyay, Sandip K

    2011-01-01

    Amla (Phyllanthus emblica L.), apart from its food value, can be used as a gastroprotective agent in non steroidal anti-inflammatory drug (NSAID)-induced gastropathy. It has been suggested that the antioxidative property of amla is the key to its therapeutic effect. Hence, on the basis of in vitro antioxidative potential, the ethanolic extract of amla (eAE) was selected for in vivo study in NSAID-induced ulcer. Intriguingly, eAE showed biphasic activity in ulcerated mice, with healing effect observed at 60 mg/kg and an adverse effect at 120 mg/kg.The dose-dependent study revealed that switching from anti-oxidant to pro-oxidant shift and immunomodulatory property could be the major cause for its biphasic effect, as evident from the total antioxidant status, thiol concentration, lipid peroxidation, protein carbonyl content followed by mucin content, PGE(2) synthesis and cytokine status. Further, Buthionine sulfoxamine (BSO) pretreatment established the potential impact of antioxidative property in the healing action of eAE. However, eAE efficiently reduced pro-inflammatory cytokine (TNF-α and IL-1β) levels and appreciably upregulate anti-inflammatory cytokine (IL-10) concentration. In conclusion, gastric ulcer healing induced by eAE was driven in a dose-specific manner through the harmonization of the antioxidative property and modulation of anti-inflammatory cytokine level.

  20. Nicotinic receptor-mediated biphasic effect on neuronal excitability in chick lateral spiriform neurons.

    PubMed

    Liu, Y-B; Guo, J-Z; Chiappinelli, V A

    2007-09-21

    Local neuronal circuits integrate synaptic information with different excitatory or inhibitory time windows. Here we report that activation of nicotinic acetylcholine receptors (nAChRs) leads to biphasic effects on excitability in chick lateral spiriform (SPL) neurons during whole cell recordings in brain slices. Carbachol (100 microM in the presence of 1 microM atropine) produced an initial short-term increase in the firing rates of SPL neurons (125+/-14% of control) that was mediated by postsynaptic nAChRs. However, after 3 min exposure to nicotinic agonists, the firing rate measured during an 800 ms depolarizing pulse declined to 19+/-7% (100 microM carbachol) or 26+/-8% (10 microM nicotine) of the control rate and remained decreased for 10-20 min after washout of the agonists. Similarly, after 60 s of electrically-stimulated release of endogenous acetylcholine (ACh) from cholinergic afferent fibers, there was a marked reduction (45+/-5% of control) in firing rates in SPL neurons. All of these effects were blocked by the nAChR antagonist dihydro-beta-erythroidine (30 microM). The inhibitory effect was not observed in Ca(2+)-free buffer. The nAChR-mediated inhibition depended on active G-proteins in SPL neurons and was prevented by the GABA(B) receptor antagonist phaclofen (200 microM), while the GABA(B) receptor agonist baclofen (10 microM) decreased firing rate in SPL neurons to 13+/-1% of control. The inhibitory response thus appears to be due to a nAChR-mediated enhancement of presynaptic GABA release, which then activates postsynaptic GABA(B) receptors. In conclusion, activation of nAChRs in the SPL initiates a limited time window for an excitatory period, after which a prolonged inhibitory effect turns off this window. The prolonged inhibitory effect may serve to protect SPL neurons from excessive excitation.

  1. Mechanisms of the biphasic effects of peroxides on the retinal vasculature of newborn and adult pigs.

    PubMed

    Abran, D; Hardy, P; Varma, D R; Chemtob, S

    1995-09-01

    We tested whether the ontogenic differences in the constrictor effects of peroxides on the retinal vasculature were modulated by dilator cyclo-oxygenase products. Retinal arteriole (100-200 microns) vasomotor response to H2O2, t-butyl hydroperoxide, and cumene hydroperoxide were studied in isolated eyecup preparations using video camera monitoring of vessel diameter. A time- and dose-dependent biphasic retinal vasomotor response to all peroxides was observed on tissues of newborn and adult pigs. A rapid vasoconstriction (first 2 min) was followed by a relaxation which was greater in the adult than in the newborn tissues. The constrictor as well as the dilator response to peroxides and the observed increase in prostanoids were blocked by the cyclo-oxygenase inhibitor indomethacin. The peroxide-induced relaxation was inhibited or markedly attenuated by the prostaglandin I2 synthase blockers, trans-2-phenyl cyclopropylamine and minoxidil on tissues of newborn and adult animals. These agents also prevented the increase of the prostaglandin I2 receptor-coupled second messenger, cyclic 3',5'-adenosine monophosphate. Our data indicate that prostaglandin I2 plays a major role in counteracting the initial constrictor effects of peroxides in the retinal vasculature, and that the reversal of this constriction is greater in the adult than the newborn. These findings suggest that reduced reversal of vasoconstriction by the dilator prostaglandin I2 during an oxidative stress in the newborn may facilitate vasoconstriction by the dilator prostaglandin I2 during an oxidative stress in the newborn may facilitate neovascularization in retinopathy of prematurity.

  2. Effect of nano-hydroxyapatite coating on the osteoinductivity of porous biphasic calcium phosphate ceramics

    PubMed Central

    2014-01-01

    Background Porous biphasic calcium phosphate (BCP) ceramics exhibit good biocompatibility and bone conduction but are not inherently osteoinductive. To overcome this disadvantage, we coated conventional porous BCP ceramics with nano-hydroxyapatite (nHA). nHA was chosen as a coating material due to its high osteoinductive potential. Methods We used a hydrothermal deposition method to coat conventional porous BCP ceramics with nHA and assessed the effects of the coating on the physical and mechanical properties of the underlying BCP. Next, its effects on mesenchymal stem cell (MSC) attachment, proliferation, viability, and osteogenic differentiation were investigated. Results nHA formed a deposited layer on the BCP surface, and synthesized nHA had a rod-like shape with lengths ranging from ~50–200 nm and diameters from ~15–30 mm. The nHA coating did not significantly affect the density, porosity, flexural strength, or compressive strength of the underlying BCP (P > 0.1). Scanning electron microscopy showed MSC attachment to the scaffolds, with a healthy morphology and anchorage to nHA crystals via cytoplasmic processes. The densities of MSCs attached on BCP and nHA-coated BCP scaffolds were 62 ± 26 cells/mm2 and 63 ± 27 cells/mm2 (P > 0.1), respectively, after 1 day and 415 ± 62 cells/mm2 and 541 ± 35 cells/mm2 (P < 0.05) respectively, after 14 days. According to an MTT assay, MSC viability was higher on nHA-coated BCP scaffolds than on BCP scaffolds (P < 0.05). In addition, MSCs on nHA-coated BCP scaffolds produced more alkaline phosphatase, collagen type I, and osteocalcin than MSCs on BCP scaffolds (P < 0.05). Conclusions Our results demonstrate that BCP scaffolds coated with nHA were more conducive for MSC adhesion, proliferation, and osteogenic differentiation than conventional, uncoated BCP scaffolds, indicating that nHA coating can enhance the osteoinductive potential of BCP ceramics, making this material more

  3. Velocity dependence of biphasic flow structuration: steady-state and oscillating flow effects

    NASA Astrophysics Data System (ADS)

    Tore Tallakstad, Ken; Jankov, Mihailo; Løvoll, Grunde; Toussaint, Renaud; Jørgen Mâløy, Knut; Grude Flekkøy, Eirik; Schmittbuhl, Jean; Schäfer, Gerhard; Méheust, Yves; Arendt Knudsen, Henning

    2010-05-01

    We study various types of biphasic flows in quasi-two-dimensional transparent porous models. These flows imply a viscous wetting fluid, and a lowly viscous one. The models are transparent, allowing the displacement process and structure to be monitored in space and time. Three different aspects will be presented: 1. In stationary biphasic flows, we study the relationship between the macroscopic pressure drop (related to relative permeability) and the average flow rate, and how this arises from the cluster size distribution of the lowly viscous fluid [1]. 2. In drainage situations, we study how the geometry of the invader can be explained, and how it gives rise to apparent dynamic capillary effects. We show how these can be explained by viscous effects on evolving geometries of invading fluid [2]. 3. We study the impact of oscillating pressure fields superimposed to a background flow over the flow regimes patterns [3]. Steady-State Two-Phase Flow in Porous Media: Statistics and Transport Properties. First, in stationary flow with a control of the flux of both fluids, we show how the pressure drop depends on the flow rate. We will show that the dynamics is dominated by the interplay between a viscous pressure field from the wetting fluid and bubble transport of a less viscous, nonwetting phase. In contrast with more studied displacement front systems, steady-state flow is in equilibrium, statistically speaking. The corresponding theoretical simplicity allows us to explain a data collapse in the cluster size distribution of lowly viscous fluid in the system, as well as the relation |?P|∞√Ca--. This allows to explain so called relative permeability effects by the morphological changes of the cluster size distribution. Influence of viscous fingering on dynamic saturation-pressure curves in porous media. Next, we study drainage in such models, and investigate the relationship between the pressure field and the morphology of the invading fluid. This allows to model

  4. Effect of biphasic calcium phosphate nanocomposite on healing of surgically created alveolar bone defects in beagle dogs

    NASA Astrophysics Data System (ADS)

    Wang, Lanlei; Guan, Aizhong; Shi, Han; Chen, Yangxi; Liao, Yunmao

    2009-09-01

    The aim of the present study was to investigate the effect of porous biphasic calcium phosphate nanocomposite (nanoBCP) scaffolds bioceramic. Alveolar bone defects were surgically created bilaterally at the buccal aspects of the upper second premolar in fourteen beagle dogs. After root conditioning with ethylenediaminetetraacetate (EDTA), nanoBCP was randomly filled in the defects and nothing was put into the contralaterals as controls. Dogs were killed at the 12th weeks. Histological observations were processed through a light microscopy. The results revealed that a great amount of functional periodontal fissures formed in the defects in the nanoBCP groups while minimal bone took shape in the controls. In this study, nanoBCP has proved to work well as a biocompatible and osteoconductive scaffold material to promote periodontal regeneration effectively.

  5. Manganese Exposure and Cognition Across the Lifespan: Contemporary Review and Argument for Biphasic Dose-Response Health Effects.

    PubMed

    Vollet, Kaitlin; Haynes, Erin N; Dietrich, Kim N

    2016-12-01

    Manganese (Mn) is both an essential micronutrient and potential neurotoxicant. This dual role underlies a growing body of literature demonstrating that Mn exhibits a biphasic dose-response relationship with neurocognitive outcomes. We reviewed recent epidemiologic studies from 2007 to 2016 that investigated the relationship between Mn exposure and cognitive outcomes across the lifespan: early life, school-aged children, and adulthood. In total, 27 research articles were included in this review: 12 pediatric and 15 adult studies (10 occupational and five environmental exposures). The majority of these studies provided evidence of the negative effects of Mn exposure on cognition. The pediatric literature provides evidence that both high and low levels of Mn are negatively associated with intellectual development. Future Mn research should include examination of non-linear relationships and multiple neurotoxicants across the lifespan and particularly during critical developmental windows.

  6. Lithium chloride has a biphasic effect on prostate cancer stem cells and a proportional effect on midkine levels

    PubMed Central

    Erguven, Mine; Oktem, Gulperi; Kara, Ali Nail; Bilir, Ayhan

    2016-01-01

    Prostate cancer (PCa) is the second most frequent type of cancer in men worldwide and the levels of differentiation growth factor midkine (MK) are increased in PCa. Cancer and/or the treatment process itself may lead to psychiatric disorders. Lithium chloride (LiCl) has anti-manic properties and has been used in cancer therapy; however, it has a queried safety profile. In addition, cancer stem cells are responsible for the heterogeneous phenotype of tumor cells; they are involved in progression, metastasis, recurrence and therapy resistance in various cancer types. The aims of the present study were to investigate the effect of different concentrations of LiCl on PCa stem cells (whether a shift from tumorigenic to non-tumorigenic cells occurs) and to determine if these results can be explained through changes in MK levels. Monolayer and spheroid cultures of human prostate stem cells and non-stem cells were incubated with low (1, 10 µM) and high (100, 500 µM) concentrations of LiCl for 72 h. Cell proliferation, apoptotic indices, MK levels and ultrastructure were evaluated. Cells stimulated with low concentrations showed high proliferation, low apoptotic indices, high MK levels and more healthy ultrastructure. Opposite results were obtained at high concentrations. Furthermore, stem cells were more sensitive to stimulation and more resistant to inhibition than non-stem cells. LiCl exhibited concentration-dependent effects on stem cell and non-stem cell groups. MK levels were not involved in the biphasic effect of LiCl; however, they were proportionally affected. To the best of our knowledge, the present study was the first to show the effect of LiCl on PCa stem cells through MK. PMID:27703531

  7. Effect of non-symmetric waveform on conduction block induced by high-frequency (kHz) biphasic stimulation in unmyelinated axon.

    PubMed

    Zhao, Shouguo; Yang, Guangning; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2014-10-01

    The effect of a non-symmetric waveform on nerve conduction block induced by high-frequency biphasic stimulation is investigated using a lumped circuit model of the unmyelinated axon based on Hodgkin-Huxley equations. The simulation results reveal that the block threshold monotonically increases with the stimulation frequency for the symmetric stimulation waveform. However, a non-monotonic relationship between block threshold and stimulation frequency is observed when the stimulation waveform is non-symmetric. Constant activation of potassium channels by the high-frequency stimulation results in the increase of block threshold with increasing frequency. The non-symmetric waveform with a positive pulse 0.4-0.8 μs longer than the negative pulse blocks axonal conduction by hyperpolarizing the membrane and causes a decrease in block threshold as the frequency increases above 12-16 kHz. On the other hand, the non-symmetric waveform with a negative pulse 0.4-0.8 μs longer than the positive pulse blocks axonal conduction by depolarizing the membrane and causes a decrease in block threshold as the frequency increases above 40-53 kHz. This simulation study is important for understanding the potential mechanisms underlying the nerve block observed in animal studies, and may also help to design new animal experiments to further improve the nerve block method for clinical applications.

  8. Infant flow biphasic nasal continuous positive airway pressure (BP- NCPAP) vs. infant flow NCPAP for the facilitation of extubation in infants' ≤ 1,250 grams: a randomized controlled trial

    PubMed Central

    2012-01-01

    Abstract Background The use of mechanical ventilation is associated with lung injury in preterm infants and therefore the goal is to avoid or minimize its use. To date there is very little consensus on what is considered the "best non-invasive ventilation mode" to be used post-extubation. The objective of this study was to compare the effectiveness of biphasic nasal continuous positive airway pressure (BP-NCPAP) vs. NCPAP in facilitating sustained extubation in infants ≤ 1,250 grams. Methods We performed a randomized controlled trial of BP-NCPAP vs. NCPAP in infants ≤ 1,250 grams extubated for the first time following mechanical ventilation since birth. Infants were extubated using preset criteria or at the discretion of the attending neonatologist. The primary outcome was the incidence of sustained extubation for 7 days. Secondary outcomes included incidence of adverse events and short-term neonatal outcomes. Results Sixty-seven infants received BP-NCPAP and 69 NCPAP. Baseline characteristics were similar between groups. The trial was stopped early due to increased use of non-invasive ventilation from birth, falling short of our calculated sample size of 141 infants per group. The incidence of sustained extubation was not statistically different between the BP-NCPAP vs. NCPAP group (67% vs. 58%, P = 0.27). The incidence of adverse events and short-term neonatal outcomes were similar between the two groups (P > 0.05) except for retinopathy of prematurity which was noted to be higher (P = 0.02) in the BP-NCPAP group. Conclusions Biphasic NCPAP may be used to assist in weaning from mechanical ventilation. The effectiveness and safety of BP-NCPAP compared to NCPAP needs to be confirmed in a large multi-center trial as our study conclusions are limited by inadequate sample size. Clinical Trials Registration # NCT00308789 Source of support Grant # 06-06, Physicians Services Incorporated Foundation, Toronto, Canada. Summit technologies Inc. provided additional NCPAP

  9. Effect of BMP2-Platelet-rich Plasma-Biphasic Calcium Phosphate Scaffold on Accelerated Osteogenesis in Mastoid Obliteration.

    PubMed

    Jang, Chul Ho; Choi, Cheol Hee; Cho, Yong Beom

    The aim of this study was to evaluate the synergistic effect of platelet-rich plasma (PRP) and recombinant human bone morphogenic protein (BMP)-2 on accelerated osteogenesis of hydroxyapatite/β-tricalcium phosphate mixture and biphasic calcium phosphate (BCP) in mastoid obliteration. To the best of our knowledge, there have been no studies reporting the enhancing effects of BCP, combined with BMP2 and PRP, on osteogenesis in mastoid obliteration. Mastoid obliteration was performed in a control group (BCP only, n=7), a group treated with BMP2 and BCP (experimental group I, n=7), and a group treated with BMP2, PRP and BCP (experimental group II, n=7). The animals were administered fluorescent bone labels for a qualitative evaluation of bone formation; oxytetracycline hydrochloride was administered at 2 weeks, calcein at 4 weeks, and alizarin red at 8 weeks. The animals were sacrificed 12 weeks post-surgery and osteogenesis was evaluated by micro-computed tomography, histological investigation, and histomorphometry. Both experimental groups showed accelerated osteogenesis compared to the control group. However, there were no statistically significant differences between experimental groups I and II. From these results, it can be concluded that BMP2 activated BCP for the enhancement of bone regeneration. However, no synergistic effect of BMP2 and PRP on the osteogenesis of BCP was observed.

  10. Effect of apatite formation of biphasic calcium phosphate ceramic (BCP) on osteoblastogenesis using simulated body fluid (SBF) with or without bovine serum albumin (BSA).

    PubMed

    Huang, Li; Zhou, Bo; Wu, Huayu; Zheng, Li; Zhao, Jinmin

    2017-01-01

    Although biphasic calcium phosphate ceramic (BCP) holds promise in therapy of bone defect, surface mineralization prior to implantation may improve the bioactivity to better integrate with the host. Immersion in simulated body fluid (SBF) and bovine serum albumin-simulated body fluid (BSA-SBF) are common methods to form apatite interface layer. This study was intended to investigate the effect of SBF and BSA-SBF treatment on the bioactivity of BCP in vitro. In this study, osteoblasts were grown on BCP with or without treatment of SBF or BSA-SBF, and detected with general observation, scanning electron microscope (SEM), cell proliferation assay, morphology observation, viability assay, alkaline phosphatase (ALP) activity assay, and osteogenic specific gene expression of alkaline phosphatase (ALPL), bone gamma-carboxyglutamate (gla) protein (BGLAP), bone morphogenetic protein 2 (BMP2), bone sialoprotein (BSP), type I collagen (COLI) and runt-related transcription factor 2 (RUNX2) after culture of 2, 5 and 8days. As the results shown, BCP pre-incubated in SBF and BSA-SBF up-regulated ALP activity and osteogenic related genes and proteins, which testified the positive effect of SBF and BSA-SBF. Especially, BSA-SBF enhanced the cell growth significantly. This study indicated that treatment by BSA-SBF is of importance for BCP before clinical application.

  11. Effect of Local Sustainable Release of BMP2-VEGF from Nano-Cellulose Loaded in Sponge Biphasic Calcium Phosphate on Bone Regeneration

    PubMed Central

    Sukul, Mousumi; Nguyen, Thuy Ba Linh; Min, Young-Ki; Lee, Sun-Young

    2015-01-01

    Bone regeneration is a coordinated process mainly regulated by multiple growth factors. Vascular endothelial growth factor (VEGF) stimulates angiogenesis and bone morphogenetic proteins (BMPs) induce osteogenesis during bone healing process. The aim of this study was to investigate how these growth factors released locally and sustainably from nano-cellulose (NC) simultaneously effect bone formation. A biphasic calcium phosphate (BCP)-NC-BMP2-VEGF (BNBV) scaffold was fabricated for this purpose. The sponge BCP scaffold was prepared by replica method and then loaded with 0.5% NC containing BMP2-VEGF. Growth factors were released from NC in a sustainable manner from 1 to 30 days. BNBV scaffolds showed higher cell attachment and proliferation behavior than the other scaffolds loaded with single growth factors. Bare BCP scaffolds and BNBV scaffolds seeded with rat bone marrow mesenchymal stem cells were implanted ectopically and orthotopically in nude mice for 4 weeks. No typical bone formation was exhibited in BNBV scaffolds in ectopic sites. BMP2 and VEGF showed positive effects on new bone formation in BNBV scaffolds, with and without seeded stem cells, in the orthotopic defects. This study demonstrated that the BNBV scaffold could be beneficial for improved bone regeneration. Stem cell incorporation into this scaffold could further enhance the bone healing process. PMID:25808925

  12. Biphasic effects of histamine on ethanol-induced gastric mucosal lesions: Studies with betahistine, dimaprit, (R). alpha. -methylhistamine and nizatidine

    SciTech Connect

    Morales, R.E.; Palitzsch, K.D.; Szabo, S. )

    1991-03-15

    In elucidating further the role that histamine (H) may play in gastroprotection against hemorrhagic mucosal lesions (HML) induced by ethanol (E), fasted S-D rats were treated with subcutaneous (s.c.) H 10, 15, 20 and 30 min before intragastric (i.g.) 100% E or H-agonists betahistine (H1) or dimaprit (H2) i.g. 30 min. before 75% E. All animals were killed 1 hr after E, HML were measured with stereomicrosopic planimetry and expressed as % of glandular stomach. The H2 antagonist nizatidine did not influence the extent of HML. As a follow up to previously reported nizatidine blockade of H2-induced gastroprotection against 75% E, nizatidine + H1 or nizatidine + H3 agonist (R){alpha}-methylhistamine was also tested. The H2 antagonist nizatidine abolished the gastroprotection by H3 but did not influence the H1-induced reduction of HML. H injected s.c. showed a dose- and time-dependent biphasic effect on E-induced gastric mucosal lesions. Both H1- and H2-agonists injected s.c. reduced the E-induced damage. Nizatidine alone failed to influence mucosal lesions, blocked gastroprotection induced by H2 or H3, but not by H1 agonists.

  13. The Effect of Alendronate Loaded Biphasic Calcium Phosphate Scaffolds on Bone Regeneration in a Rat Tibial Defect Model

    PubMed Central

    Park, Kwang-Won; Yun, Young-Pil; Kim, Sung Eun; Song, Hae-Ryong

    2015-01-01

    This study investigated the effect of alendronate (Aln) released from biphasic calcium phosphate (BCP) scaffolds. We evaluated the in vitro osteogenic differentiation of Aln/BCP scaffolds using MG-63 cells and the in vivo bone regenerative capability of Aln/BCP scaffolds using a rat tibial defect model with radiography, micro-computed tomography (CT), and histological examination. In vitro studies included the surface morphology of BCP and Aln-loaded BCP scaffolds visualized using field-emission scanning electron microscope, release kinetics of Aln from BCP scaffolds, alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The in vitro studies showed that sustained release of Aln from the BCP scaffolds consisted of porous microstructures, and revealed that MG-63 cells cultured on Aln-loaded BCP scaffolds showed significantly increased ALP activity, calcium deposition, and gene expression compared to cells cultured on BCP scaffolds. The in vivo studies using radiograph and histology examination revealed abundant callus formation and bone maturation at the site in the Aln/BCP groups compared to the control group. However, solid bony bridge formation was not observed at plain radiographs until 8 weeks. Micro-CT analysis revealed that bone mineral density and bone formation volume were increased over time in an Aln concentration-dependent manner. These results suggested that Aln/BCP scaffolds have the potential for controlling the release of Aln and enhance bone formation and mineralization. PMID:26561810

  14. The Effect of Covalently Immobilized FGF-2 on Biphasic Calcium Phosphate Bone Substitute on Enhanced Biological Compatibility and Activity.

    PubMed

    Moon, Kyung-Suk; Choi, Eun-Joo; Oh, Seunghan; Kim, Sungtae

    2015-01-01

    The purpose of this research was to covalently graft fibroblast growth factor 2 (FGF-2) onto biphasic calcium phosphate (BCP) via a bifunctional cross-linker technique and to estimate the optimal dose of FGF-2 resulting in the best osteogenic differentiation of human mesenchymal stem cells (hMSCs). SEM observation revealed that the surface of the 100 ng FGF-2 coated BCP was completely covered with the nanoparticles expected to be from the silane coupling agent. XRD, FT-IR, and XPS analysis showed that silane treatment, bifunctional cross-linker coating, and FGF-2 covalent grafts were conducted successfully without deforming the crystalline structure of BCP. An MTT assay demonstrated that FGF-2 coated BCP had good biocompatibility, regardless of the concentration of FGF-2, after 24 or 48 h of incubation. An alkaline phosphatase (ALP) activity assay (14 days of incubation) and the ALP gene expression level of real-time PCR analysis (7 days of incubation) revealed that 50, 100, and 200 ng FGF-2 coated BCP induced the highest activities among all experimental groups and control group (P < 0.05). Thus, low concentrations of FGF-2 facilitated excellent osteogenesis and were effective at enhancing osteogenic potential. Also, the bifunctional cross-linker technique is expected to be a more feasible way to induce osteogenic differentiation while minimizing the risk of FGF-2 overdose.

  15. Interaction of a cationic acrylate polymer with caseins: biphasic effect of Eudragit E100 on the stability of casein micelles.

    PubMed

    Ausar, Salvador F; Bianco, Ismael D; Castagna, Leonardo F; Alasino, Roxana V; Beltramo, Dante M

    2003-07-16

    When whole or skim milk was incubated with the cationic acrylate polymer Eudragit E100, a biphasic effect on the stability of casein micelles was observed. A precipitation phase was observed at low polymer/casein ratios. Strikingly, a solubilization phase of the aggregates was observed when the ratios of polymer/casein were increased. Purified alpha(s)-, beta-, and kappa-caseins or dephosphorylated caseins were equally precipitated and resolubilized by the cationic polymer, indicating no special selectivity for a particular protein or phosphate residue for these events. An increase in the size of the aggregates as the optimum precipitating amount of Eudragit E100 was reached suggests a crossbridging of the micelles by the polymer. The inhibition of the precipitation phase by high ionic strength indicates that electrostatic interactions play a critical role in complex formation. Furthermore, a dramatic reduction in size of the protein colloidal particles upon solubilization of the aggregates was observed by dynamic light scattering, indicating a dissociation of the micellar structure. Taken together, the results indicate that at low concentration Eudragit E100 may act as a precipitant of casein micelles, mainly by ionic interaction and at high concentration as an amphipathic agent, solubilizing casein micelles with a disruption of their internal structure.

  16. Biphasic dose response in low level light therapy.

    PubMed

    Huang, Ying-Ying; Chen, Aaron C-H; Carroll, James D; Hamblin, Michael R

    2009-09-01

    The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response.

  17. Biphasic Dose Response in Low Level Light Therapy

    PubMed Central

    Huang, Ying-Ying; Chen, Aaron C.-H.; Carroll, James D.; Hamblin, Michael R.

    2009-01-01

    The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response. PMID:20011653

  18. Overview of the effect of salts on biphasic ionic liquid/water solvent extraction systems: anion exchange, mutual solubility, and thermomorphic properties.

    PubMed

    Dupont, David; Depuydt, Daphne; Binnemans, Koen

    2015-06-04

    Hydrophobic (water-immiscible) ionic liquids (ILs) are frequently used as organic phase in solvent extraction studies. These biphasic IL/water extraction systems often also contain metal salts or mineral acids, which can significantly affect the IL trough (un)wanted anion exchange and changes in the solubility of IL in the aqueous phase. In the case of thermomorphic systems, variations in the cloud point temperature are also observed. All these effects have important repercussions on the choice of IL, suitable for a certain extraction system. In this paper, a complete overview of the implications of metal salts on biphasic IL/water systems is given. Using the Hofmeister series as a starting point, a range of intuitive prediction models are introduced, supported by experimental evidence for several hydrophobic ILs, relevant to solvent extraction. Particular emphasis is placed on the IL betainium bis(trifluoromethylsulfonyl)imide [Hbet][Tf2N]. The aim of this work is to provide a comprehensive interpretation of the observed effects of metal salts, so that it can be used to predict the effect on any given biphasic IL/water system instead of relying on case-by-case reports. These prediction tools for the impact of metal salts can be useful to optimize IL synthesis procedures, extraction systems and thermomorphic properties. Some new insights are also provided for the rational design of ILs with UCST or LCST behavior based on the choice of IL anion.

  19. Effects of Biphasic Current Pulse Frequency, Amplitude, Duration and Interphase Gap on Eye Movement Responses to Prosthetic Electrical Stimulation of the Vestibular Nerve

    PubMed Central

    Davidovics, Natan S.; Fridman, Gene Y.; Chiang, Bryce; Della Santina, Charles C.

    2011-01-01

    An implantable prosthesis that stimulates vestibular nerve branches to restore sensation of head rotation and vision-stabilizing reflexes could benefit individuals disabled by bilateral loss of vestibular (inner ear balance) function. We developed a prosthesis that partly restores normal function in animals by delivering pulse frequency modulated (PFM) biphasic current pulses via electrodes implanted in semicircular canals. Because the optimal stimulus encoding strategy is not yet known, we investigated effects of varying biphasic current pulse frequency, amplitude, duration and interphase gap on vestibulo-ocular reflex (VOR) eye movements in chinchillas. Increasing pulse frequency increased response amplitude while maintaining a relatively constant axis of rotation. Increasing pulse amplitude (range 0–325 μA) also increased response amplitude but spuriously shifted eye movement axis, probably due to current spread beyond the target nerve. Shorter pulse durations (range 28–340 μs) required less charge to elicit a given response amplitude and caused less axis shift than longer durations. Varying interphase gap (range 25–175 μs) had no significant effect. While specific values reported herein depend on microanatomy and electrode location in each case, we conclude that PFM with short duration biphasic pulses should form the foundation for further optimization of stimulus encoding strategies for vestibular prostheses intended to restore sensation of head rotation. PMID:20813652

  20. Post stimulus effects of high frequency biphasic electrical current on a fibre's conductibility in isolated frog nerves

    NASA Astrophysics Data System (ADS)

    Liu, Hailong; Zhu, Linlin; Sheng, Shulei; Sun, Lifei; Zhou, Hongmin; Tang, Hong; Qiu, Tianshuang

    2013-06-01

    Objective. High frequency biphasic (HFB) electrical currents are widely used in nerve blocking studies. Their safety margins largely remain unknown and need to be investigated. Approach. This study, exploring the post stimulus effects of HFB electrical currents on a nerve's conductibility, was performed on bullfrog sciatic nerves. Both compound action potentials (CAPs) and differential CAPs (DCAPs, i.e. control CAPs subtracted by CAPs following HFB currents) were obtained, and N1 and N2 components, which were the first and second upward components of DCAPs, were used for analyses of the effects introduced by HFB electrical stimulation. Main results. First, HFB currents of 10 kHz at a completely blocking threshold were applied for 5 s. The maximum amplitudes and conducting velocities of the CAPs were significantly (P < 0.02) decreased within the observed period (60 s) following HFB currents. The DCAPs displayed clear N1 and N2 components, demonstrating respectively the losses of the fibres' normal conductibility and the appearances of new delayed conductions. Decreases of N1 amplitudes along time, regarded as the recovery of the nerve's conductibility, exhibited two distinct phases: a fast one lasting several seconds and a slow one lasting longer than 5 min. Further tests showed a linear relationship between the HFB stimulation durations and recovering periods of N1 amplitudes. Supra-threshold blocking did not cause higher N1 amplitudes. Significance. This study indicates that HFB electrical currents lead to long lasting post stimulus reduction of a nerve's conductibility, which might relate to potential nerve injuries. A possible mechanism, focusing on changes in intracellular and periaxonal ionic concentrations, was proposed to underlie the reduction of the nerve's conductibility and potential nerve injuries. Greater caution and stimulation protocols with greater safety margins should be explored when utilizing HFB electrical current to block nerve conductions.

  1. Biphasic effects of orexin-A on autonomic nerve activity and lipolysis.

    PubMed

    Shen, Jiao; Tanida, Mamoru; Yao, Jia-Fei; Niijima, Akira; Nagai, Katsuya

    2008-10-24

    Previously, we showed that orexin-A, a 33-aa peptide, influences renal sympathetic nerve activity. Because the autonomic nervous system plays an important role in the regulation of lipid metabolism, we investigated the in vivo effects of orexin-A on the sympathetic nerve activity innervating white adipose tissue (WAT-SNA) and lipolysis. We found that intracerebroventricular (icv) administration of orexin-A at doses of 1 microg/rat and 10 ng/rat elevated and suppressed WAT-SNA, respectively. The effect of the high dose of orexin-A (1 microg/rat) was eliminated by pretreatment with diphenhydramine hydrochloride, a histamine H(1) receptor antagonist. In contrast, the effect of the low dose of orexin-A (10 ng/rat) was suppressed by thioperamide maleate salt, a histamine H(3) receptor antagonist. Moreover, icv administration of 1 microg/rat and 10 ng/rat of orexin-A increased and decreased the levels of plasma free fatty acids (FFAs), respectively. The effect of 1 microg/rat of orexin-A on plasma FFA was eliminated by propranolol hydrochloride, a beta-adrenergic receptor blocker, and also by diphenhydramine. The effect of orexin-A at dose of 10 ng/rat disappeared by pretreatment with atropine sulfate, a muscarinic receptor blocker, and thioperamide maleate salt. Our results suggest that high doses of orexin-A may regulate the lipolytic processes in adipose tissue through facilitation of the sympathetic nervous system, which is driven by histamine neurons through the H(1) receptor, and that the beta(3)-receptor may be involved in this enhanced lipolytic response. Low doses of orexin-A, on the other hand, may lower lipolysis by suppressing sympathetic nerve activity via the H(3)-receptor, and the muscarinic receptor may be related to this response.

  2. Biphasic effect of 1,25-dihydroxyvitamin D3 on primary mouse epidermal keratinocyte proliferation.

    PubMed

    Bollag, W B; Ducote, J; Harmon, C S

    1995-05-01

    1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] has been proposed as a physiologic regulator of keratinocyte growth and differentiation. Utilizing a proliferative serum-free culture system, we have found that a physiologic (picomolar) concentrations this hormone stimulated proliferation of primary mouse epidermal keratinocytes; at higher (nanomolar to micromolar) doses, growth was inhibited by 1,25(OH)2D3. We investigated the nature of the signal transduction mechanism underlying the response to 1,25(OH)2D3 and observed little or no effect of either low or high concentrations of the hormone on cytosolic calcium levels or Fos expression. Furthermore, the protein kinase C inhibitor, Ro 31-7549, had very little effect on the growth inhibition induced by a high dose (1 microM) of 1,25(OH)2D3. This lack of rapid signal transduction events was consistent with the inability of a short (4-hour) exposure to 1,25(OH)2D3 to initiate a complete growth-inhibitory response as measured using [3H]thymidine incorporation. Our results indicate that physiologic concentrations of 1,25(OH)2D3 are required for optimal keratinocyte growth. Furthermore, we found no evidence of rapid effects of 1,25(OH)2D3 and suggest that in mouse epidermal keratinocytes, the response to this hormone is mediated by a slow transduction pathway, such as that activated by the intracellular 1,25(OH)2D3 receptor (VDR).

  3. Biphasic effect of melanocortin agonists on metabolic rate and body temperature.

    PubMed

    Lute, Beth; Jou, William; Lateef, Dalya M; Goldgof, Margalit; Xiao, Cuiying; Piñol, Ramón A; Kravitz, Alexxai V; Miller, Nicole R; Huang, Yuning George; Girardet, Clemence; Butler, Andrew A; Gavrilova, Oksana; Reitman, Marc L

    2014-08-05

    The melanocortin system regulates metabolic homeostasis and inflammation. Melanocortin agonists have contradictorily been reported to both increase and decrease metabolic rate and body temperature. We find two distinct physiologic responses occurring at similar doses. Intraperitoneal administration of the nonselective melanocortin agonist MTII causes a melanocortin-4 receptor (Mc4r)-mediated hypermetabolism/hyperthermia. This is preceded by a profound, transient hypometabolism/hypothermia that is preserved in mice lacking any one of Mc1r, Mc3r, Mc4r, or Mc5r. Three other melanocortin agonists also caused hypothermia, which is actively achieved via seeking a cool environment, vasodilation, and inhibition of brown adipose tissue thermogenesis. These results suggest that the hypometabolic/hypothermic effect of MTII is not due to a failure of thermoregulation. The hypometabolism/hypothermia was prevented by dopamine antagonists, and MTII selectively activated arcuate nucleus dopaminergic neurons, suggesting that these neurons may contribute to the hypometabolism/hypothermia. We propose that the hypometabolism/hypothermia is a regulated response, potentially beneficial during extreme physiologic stress.

  4. Biphasic Effect of Diabetes on Neuronal Nitric Oxide Release in Rat Mesenteric Arteries

    PubMed Central

    Sastre, Esther; Caracuel, Laura; Blanco-Rivero, Javier; Callejo, María; Xavier, Fabiano E.; Balfagón, Gloria

    2016-01-01

    Introduction We analysed possible time-dependent changes in nitrergic perivascular innervation function from diabetic rats and mechanisms implicated. Materials and Methods In endothelium-denuded mesenteric arteries from control and four- (4W) and eight-week (8W) streptozotocin-induced diabetic rats the vasoconstriction to EFS (electrical field stimulation) was analysed before and after preincubation with L-NAME. Neuronal NO release was analysed in the absence and presence of L-arginine, tetrahydrobiopterine (BH4) and L-arginine plus BH4. Superoxide anion (O2-), peroxynitrite (ONOO-) and superoxide dismutase (SOD) activity were measured. Expressions of Cu-Zn SOD, nNOS, p-nNOS Ser1417, p-nNOS Ser847, and Arginase (Arg) I and II were analysed. Results EFS response was enhanced at 4W, and to a lesser extent at 8W. L-NAME increased EFS response in control rats and at 8W, but not at 4W. NO release was decreased at 4W and restored at 8W. L-arginine or BH4 increased NO release at 4W, but not 8W. SOD activity and O2- generation were increased at both 4W and 8W. ONOO- decreased at 4W while increased at 8W. Cu-Zn SOD, nNOS and p-NOS Ser1417 expressions remained unmodified at 4W and 8W, whereas p-nNOS Ser847 was increased at 4W. ArgI was overexpressed at 4W, remaining unmodified at 8W. ArgII expression was similar in all groups. Conclusions Our results show a time-dependent effect of diabetes on neuronal NO release. At 4W, diabetes induced increased O2- generation, nNOS uncoupling and overexpression of ArgI and p-nNOS Ser847, resulting in decreased NO release. At 8W, NO release was restored, involving normalisation of ArgI and p-nNOS Ser847 expressions. PMID:27272874

  5. Distribution of cortical granules and meiotic maturation of canine oocytes in bi-phasic systems.

    PubMed

    Apparicio, Maricy; Mostachio, Giuliano Q; Motheo, Tathiana F; Alves, Aracelle E; Padilha, Luciana; Pires-Butler, Eliandra A; Savi, Paula A P; Uscategui, Ricardo A R; Luvoni, Gaia C; Vicente, Wilter R R

    2015-09-01

    The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72h in base medium (BM) with 10IUmL(-1) human chorionic gonadotrophin (hCG), 1μgmL(-1) progesterone (P4) and 1μgmL(-1) oestradiol (E2); in bi-phasic System B oocytes were matured for 48h in BM with hCG and for 24h in BM with P4; in bi-phasic System C oocytes were matured for 48h in BM with hCG, P4 and E2, and for 24h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P<0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P<0.001). The stage of the oestrous cycle did not influence maturation rates.

  6. Topical hindpaw application of L-menthol decreases responsiveness to heat with biphasic effects on cold sensitivity of rat lumbar dorsal horn neurons.

    PubMed

    Klein, A H; Sawyer, C M; Takechi, K; Davoodi, A; Ivanov, M A; Carstens, M I; Carstens, E

    2012-09-06

    Menthol is used in pharmaceutical applications because of its desired cooling and analgesic properties. The neural mechanism by which topical application of menthol decreases heat pain is not fully understood. We investigated the effects of topical menthol application on lumbar dorsal horn wide dynamic range and nociceptive-specific neuronal responses to noxious heat and cooling of glabrous hindpaw cutaneous receptive fields. Menthol increased thresholds for responses to noxious heat in a concentration-dependent manner. Menthol had a biphasic effect on cold-evoked responses, reducing the threshold (to warmer temperatures) at a low (1%) concentration and increasing threshold and reducing response magnitude at high (10%, 40%) concentrations. Menthol had little effect on responses to innocuous or noxious mechanical stimuli, ruling out a local anesthetic action. Application of 40% menthol to the contralateral hindpaw tended to reduce responses to cooling and noxious heat, suggesting a weak heterosegmental inhibitory effect. These results indicate that menthol has an analgesic effect on heat sensitivity of nociceptive dorsal horn neurons, as well as biphasic effects on cold sensitivity, consistent with previous behavioral observations.

  7. Teacher Effectiveness: A Position.

    ERIC Educational Resources Information Center

    Scott, Myrtle

    1969-01-01

    This document summarizes the highlights of research on teacher effectiveness and concludes with recommendations based on a synthesis of this past work. The various methodologies that have been used are discussed, from rating scales to objective observation techniques, such as OScAR and the ecological studies. The major problems in teacher…

  8. The effects of melatonin on electrical field stimulation-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia after unilateral testicular torsion/detorsion.

    PubMed

    Barun, Süreyya; Ekingen, Gülşen; Mert Vural, Ismail; Türkyilmaz, Zafer; Başaklar, Can; Kale, Nuri; Sevim Ercan, Zeynep; Sarioğlu, Yusuf

    2005-05-01

    It is not known whether there is an impairment in vas deferens motility after unilateral testicular torsion/detorsion. Therefore, we aimed to determine whether the electrical field stimulation (EFS)-evoked biphasic contractions are altered in ipsilateral and contralateral rat vasa deferentia obtained from animals exposed to the unilateral testicular torsion/detorsion procedure. We also evaluated the effects of melatonin (MLT), which is a strong antioxidant, on these contractile responses. Rats were subjected to torsion of the left testis for 2 h and then detorsion was performed. Contractility studies were carried out 2 h or 24 h after detorsion. Vas deferens strips were prepared from both the ipsilateral and the contralateral site 2 h or 24 h after the detorsion procedure to record EFS-evoked biphasic twitch responses. The same experimental protocol was repeated for the MLT-treated rats. Both phases of EFS-evoked contractions were decreased after torsion/detorsion in the ipsilateral vas deferens. MLT treatment increased torsion/detorsion-induced reduction of both phases of contractions after 2 h and 24 h. In the contralateral vas deferens, the first phase of EFS-evoked contractions was not changed, while the second phase of contractions was diminished 2 h and 24 h after detorsion. Although MLT decreased the second phase of contractions 2 h and 24 h after detorsion, it reduced the first phase of contractions only 2 h after detorsion. These results suggest that MLT produces an inhibition on EFS-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia following unilateral testicular torsion/detorsion in the rat.

  9. Supersaturation, nucleation, and crystal growth during single- and biphasic dissolution of amorphous solid dispersions: polymer effects and implications for oral bioavailability enhancement of poorly water soluble drugs.

    PubMed

    Sarode, Ashish L; Wang, Peng; Obara, Sakae; Worthen, David R

    2014-04-01

    The influence of polymers on the dissolution, supersaturation, crystallization, and partitioning of poorly water soluble compounds in biphasic media was evaluated. Amorphous solid dispersions (ASDs) containing felodipine (FLD) and itraconazole (ITZ) were prepared by hot melt mixing (HMM) using various polymers. The ASDs were analyzed using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and HPLC. Amorphous drug conversion was confirmed using DSC and PXRD, and drug stability by HPLC. Single- and biphasic dissolution studies of the ASDs with concurrent dynamic light scattering (DLS) and polarized light microscopic (PLM) analysis of precipitated drugs were performed. HPLC revealed no HMM-induced drug degradation. Maximum partitioning into the organic phase was dependent upon the degree of supersaturation. Although the highest supersaturation of FLD was attained using Eudragit® EPO and AQOAT® AS-LF with better nucleation and crystal growth inhibition using the latter, higher partitioning of the drug into the organic phase was achieved using Pharmacoat® 603 and Kollidon® VA-64 by maintaining supersaturation below critical nucleation. Critical supersaturation for ITZ was surpassed using all of the polymers, and partitioning was dependent upon nucleation and crystal growth inhibition in the order of Pharmacoat® 603>Eudragit® L-100-55>AQOAT® AS-LF. HMM drug-polymer systems that prevent drug nucleation by staying below critical supersaturation are more effective for partitioning than those that achieve the highest supersaturation.

  10. Salt Effect Model for Aqueous Solubility of TBP in a 5 to 100% TBP/n-Dodecane-Nitric Acid-Water Biphasic System at 298.2 K

    SciTech Connect

    Kumar, Shekhar; Koganti, Sudhir Babu

    2000-02-15

    The solubilities of nonelectrolytes in aqueous electrolyte solutions have traditionally been modeled by using the Setschenow equation for salt effect. The aqueous solubility of tri-n-butyl phosphate (TBP) during operating conditions of the Purex process is an important parameter for safety considerations. Use of the Setschenow equation for aqueous solubility of TBP under limited conditions has been reported in the literature. However, there is no general model available to account for the presence of the diluent and for the case of multicomponent electrolyte solutions in which only some electrolytes are solvated and extracted by TBP. An extended salt effect model is proposed for predicting the aqueous solubility of TBP in a 5 to 100% TBP/n-dodecane-nitric acid-water biphasic system at 298.2 K. The literature data on TBP solubility were correlated to aqueous acid concentration, diluent concentration in the solvents, and an interaction parameter for electrolytic solutes (extracted or not extracted by TBP)

  11. MBCP biphasic calcium phosphate granules and tissucol fibrin sealant in rabbit femoral defects: the effect of fibrin on bone ingrowth.

    PubMed

    Le Guehennec, Laurent; Goyenvalle, Eric; Aguado, Eric; Pilet, Paul; Bagot D'Arc, Maurice; Bilban, Melitta; Spaethe, Reiner; Daculsi, Guy

    2005-01-01

    An ageing population implies an increase in bone and dental diseases, which are in turn a source of numerous handicaps. These pathologies are an expensive burden for the European health system. As no specific bioactive materials are efficient enough to cope with this burden, we have to develop an injectable, mouldable, self-hardening bone substitute to support bone tissue reconstruction and augmentation. New, highly bioactive and suitable biomaterials have been developed to replace bone grafts in orthopedic revision and maxillofacial surgery for bone augmentation. These mouldable, self-hardening materials are based on the association of MBCP Biphasic Calcium Phosphate Granules and Tissucol Fibrin Sealant. The in vivo evaluation of ingrowth in relation to the composite was made in an experiment on rabbits. The results indicate that in the presence of fibrin sealant, newly-formed bone developed at a small distance from the surface of the calcium phosphate ceramic. Two different bone apposition processes were identified. Without the fibrin component (MBCP group), bone rested directly on the surface of the granules. This observation is commonly described as osteoconduction in calcium phosphate materials. On the contrary, the presence of the fibrinogen component seemed to modify this standard osteoconduction phenomenon: the newly-formed bone essentially grew at a distance from the surface of the granules, on the fibrillar network, and could be considered as an inductive phenomenon for osteogenic cell differentiation from mesenchymal stem cells.

  12. Effects of Nano-biphasic Calcium Phosphate Composite on Bioactivity and Osteoblast Cell Behavior in Tissue Engineering Applications

    PubMed Central

    Ebrahimian-Hosseinabadi, Mehdi; Etemadifar, Mohammadreza; Ashrafizadeh, Fakhredin

    2016-01-01

    In this paper, preparation, bioactivity, and osteoblast cell behavior of cortical bone derived nano-biphasic calcium phosphate (nano-BCP) are presented. The calcined bovine bone samples with the addition of di-ammonium hydrogen phosphate were heated at 700°C for 100 min, and thus nano-BCP with the composition of 63/37 hydroxyapatite (HA)/β-tricalcium phosphate (β-TCP) was produced. Scanning electron microscopy (SEM) images, energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analysis of immersed samples in simulated body fluid (SBF) solution showed that a uniform layer was formed on the surface after 7 days with the chemical composition of HA. The results indicated that the nano-BCP sample developed excellent bioactivity after 28 days. The nano-BCP samples showed better cell proliferation compared to pure HA samples. After 7 days in cell culture, the prepared nano-BCP (HA/β-TCP) exhibited the maximum proliferation of the MG-63 osteoblast cells. PMID:28028500

  13. Effects of Nano-biphasic Calcium Phosphate Composite on Bioactivity and Osteoblast Cell Behavior in Tissue Engineering Applications.

    PubMed

    Ebrahimian-Hosseinabadi, Mehdi; Etemadifar, Mohammadreza; Ashrafizadeh, Fakhredin

    2016-01-01

    In this paper, preparation, bioactivity, and osteoblast cell behavior of cortical bone derived nano-biphasic calcium phosphate (nano-BCP) are presented. The calcined bovine bone samples with the addition of di-ammonium hydrogen phosphate were heated at 700°C for 100 min, and thus nano-BCP with the composition of 63/37 hydroxyapatite (HA)/β-tricalcium phosphate (β-TCP) was produced. Scanning electron microscopy (SEM) images, energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analysis of immersed samples in simulated body fluid (SBF) solution showed that a uniform layer was formed on the surface after 7 days with the chemical composition of HA. The results indicated that the nano-BCP sample developed excellent bioactivity after 28 days. The nano-BCP samples showed better cell proliferation compared to pure HA samples. After 7 days in cell culture, the prepared nano-BCP (HA/β-TCP) exhibited the maximum proliferation of the MG-63 osteoblast cells.

  14. Negative effects of positive reinforcement.

    PubMed

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive-those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures.

  15. Negative effects of positive reinforcement

    PubMed Central

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive—those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures. ImagesFigure 1Figure 2 PMID:22478391

  16. Effect of methanol on the phase-transition properties of glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulations: in quest of the biphasic effect.

    PubMed

    Laner, Monika; Hünenberger, Philippe H

    2015-02-01

    The effect of methanol on the phase and phase-transition properties of a 2×8×8 glycerol-1-monopalmitate bilayer patch is investigated using a series of 239 molecular dynamics simulations on the 180 ns timescale, considering methanol concentrations cM and temperatures T in the ranges 0-12.3M and 302-338 K, respectively. The results in the form of hysteresis-corrected transition temperatures Tm are compatible with the expected features of the biphasic effect, with a reversal concentration crev of about 5.2 M. Below this concentration, the main transition is between the liquid crystal (LC) and gel (GL) phases, and Tm decreases upon increasing cM. Above this concentration, the interdigitated (ID) phase is the stable ordered phase instead, and Tm slightly increases upon increasing T up to about 10 M. The analysis of the structural and dynamical properties also reveals very different sensitivities and responses of the three phases to changes in cM. In particular, the properties of the GL phase are insensitive to cM, whereas those of the LC and ID phases are altered via an increase of the area per lipid. For the LC phase, increasing cM promotes disorder and fluidity. For the ID phase, in contrast, increasing cM up to about 10 M slightly increases the ordering and rigidity. Two side issues are also addressed, concerning: (i) the occurrence tilt-precession motions in the GL and ID phases; (ii) the influence of the pressure coupling scheme employed in the simulations, semi- or fully-anisotropic, on the simulation results.

  17. Effect of self-assembled nanofibrous silk/polycaprolactone layer on the osteoconductivity and mechanical properties of biphasic calcium phosphate scaffolds.

    PubMed

    Roohani-Esfahani, S I; Lu, Z F; Li, J J; Ellis-Behnke, R; Kaplan, D L; Zreiqat, H

    2012-01-01

    We here present the first successful report on combining nanostructured silk and poly(ε-caprolactone) (PCL) with a ceramic scaffold to produce a composite scaffold that is highly porous (porosity ∼85%, pore size ∼500 μm, ∼100% interconnectivity), strong and non-brittle with a surface that resembles extracellular matrix (ECM). The ECM-like surface was developed by self-assembly of nanofibrous structured silk (20-80 nm diameter, similar to native collagen found in ECM) over a thin PCL layer which is coated on biphasic calcium phosphate (BCP) scaffolds. The effects of different concentrations of silk solution on the mechanical and physical properties of the scaffolds were also comprehensively examined. Our results showed that using silk only (irrespective of concentration) for the modification of ceramic scaffolds could drastically reduce the compressive strength of the modified scaffolds in aqueous media, and the modification made a limited contribution to improving scaffold toughness. Using PCL/nanostructured silk the compressive strength and modulus of the modified scaffolds reached 0.42 MPa (compared with 0.07 MPa for BCP) and ∼25 MPa (compared with 5 MPa for BCP), respectively. The failure strain of the modified scaffold increased more than 6% compared with a BCP scaffold (failure strain of less than 1%), indicating a transformation from brittle to elastic behavior. The cytocompatibility of ECM-like composite scaffolds was investigated by studying the attachment, morphology, proliferation and bone-related gene expression of primary human bone-derived cells. Cells cultured on the developed scaffolds for 7 days had significant up-regulation of cell proliferation (∼1.6-fold higher, P<0.001) and osteogenic gene expression levels (collagen type I, osteocalcin and bone sialoprotein) compared with the other groups tested.

  18. Biphasic effects of baclofen on phrenic motoneurons: possible involvement of two types of gamma-aminobutyric acid (GABA) receptors.

    PubMed

    Lalley, P M

    1983-08-01

    Intravenous injections of baclofen have two general dose-dependent effects on phrenic motoneurons in anesthetized cats. Small doses (0.5-1.5 mg/kg) increase the frequency of action potentials recorded from single motoneurons and from the phrenic nerve, whereas large doses (2-10 mg/kg) reduce or abolish action potentials. The increase in frequency produced by small doses is accompanied by membrane depolarization and, in most experiments, by increased input resistance. Large doses hyperpolarize phrenic motoneurons and produce greater increases in input resistance. Extracellular recording during microelectrophoretic application of baclofen reveals only one effect, depression of cell firing, at all effective current strengths. The low dose stimulatory effect of i.v. baclofen is attributed to disinhibition, whereas the depression by large doses is attributed to disfacilitation. During incomplete inhibition by baclofen, CO2 administration further depresses phrenic nerve activity. Bicuculline (100-600 micrograms/kg i.v.) and picrotoxin (900 micrograms/kg i.v.) restore firing depressed by baclofen, whereas strychnine (80-1280 micrograms/kg) does not. 3-Aminopropanesulfonic acid (5-75 mg/kg i.v.) an agonist at gamma-aminobutyric acid-A receptor sites, depresses phrenic nerve activity. It is suggested that the low dose stimulatory effects are related to actions at gamma-aminobutyric acid-B receptors, whereas the high dose depressant effects are related, at least in part, to activation of gamma-aminobutyric acid-A receptors.

  19. Biphasic nanofibrous constructs with seeded cell layers for osteochondral repair.

    PubMed

    Jin, Guang-Zhen; Kim, Jung-Ju; Park, Jeong-Hui; Seo, Seog-Jin; Kim, Joong-Hyun; Lee, Eun-Jung; Kim, Hae-Won

    2014-11-01

    Biphasic scaffolds have gained increasing attention for the regeneration of osteochondral interfacial tissue because they are expected to effectively define the interfacial structure of tissue that comprises stratified cartilage with a degree of calcification. Here, we propose a biphasic nanofiber construct made of poly(lactide-co-caprolactone) (PLCL) and its mineralized form (mPLCL) populated with cells. Primary rat articular chondrocytes (ACs) and bone marrow-derived mesenchymal stem cells (MSCs) were cultured on the layers of bare PLCL and mPLCL nanofibers, respectively, for 7 days, and the biphasic cell-nanofiber construct was investigated at 4 weeks after implantation into nude mice. Before implantation, the ACs and MSCs grown on each layer of PLCL and mPLCL nanofibers exhibited phenotypes typical of chondrocytes and osteoblasts, respectively, under proper culture conditions, as analyzed by electron microscopy, histological staining, cell growth kinetics, and real-time polymerase chain reaction. The biphasic constructs also showed the development of a possible formation of cartilage and bone tissue in vivo. Results demonstrated that the cell-laden biphasic nanofiber constructs may be useful for the repair of osteochondral interfacial tissue structure.

  20. Biphasic effect of alpha-linolenic acid on glucose-induced dysmorphogenesis and lipoperoxidation in whole rat embryo in culture.

    PubMed

    Chirino-Galindo, Gladys; Barrera-Argüelles, Jorge-Israel; Trejo-González, Ninna-Leslie; Mejía-Zepeda, Ricardo; Palomar-Morales, Martín

    2017-03-18

    Type 1 diabetes mellitus complicated with pregnancy, know as diabetic embryopathy, is the cause of neonatal malformations and low for gestational age neonates. With the use of the whole-embryo culture system, it has been demonstrated that high glucose causes embryo dysmorphogenesis, and that oxidative stress appears to be the main mechanism. In recent years, beneficial effect of omega-3 fatty acids has been demonstrated in various diabetic models, and in diabetic complications. Since diabetic embryopathy is mediated probably through membrane lipoperoxidation, This study was designed to find if omega-3 fatty acids could ameliorate the effect of high glucose over the dysmorphogenesis of whole rat embryo in culture. Postimplantational rat embryos were cultured in hyperglycemic media, with addition of alpha-linolenic acid, and morphologic and morphometric parameters were registered. Also, lipoperoxidation and fatty acids composition were measured in cultured embryos. Growth of embryos cultured in presence of glucose was very affected, whereas lipoperoxidation was increased, and it was found that Triton X-100 causes similar results than glucose. Addition of low micromolar doses of alpha-linolenic acid overcome the effect of high glucose or Triton X-100, but higher doses does not ameliorates the effects of the carbohydrate or the detergent. Paradoxically, there are not significant changes in fatty acids composition, although the U/S fatty acids ratio shows an increasing tendency by high glucose and a normalizing tendency by omega-3 fatty acids. In conclusion, glucose and Triton X-100 induces in vitro dysmorphogenesis in post-implantational rat embryos associated with increased lipoperoxidation; and this nocive effect could be ameliorated by low micromolar doses of ALA.

  1. Biphasic effects of l-ascorbate on the tumoricidal activity of non-thermal plasma against malignant mesothelioma cells.

    PubMed

    Shi, Lei; Wang, Yue; Ito, Fumiya; Okazaki, Yasumasa; Tanaka, Hiromasa; Mizuno, Masaaki; Hori, Masaru; Richardson, Des R; Toyokuni, Shinya

    2016-09-01

    Non-thermal plasma (NTP) is a recently developed technology that elicits a variety of biological effects. This includes cancer cell-specific cytotoxicity, which is mainly attributed to the regional generation of reactive oxygen species (ROS). We studied the effects of NTP on malignant mesothelioma (MM) and its modulation by l-ascorbate. l-ascorbate is a major water-soluble anti-oxidant in vivo, but its pro-oxidant activity in vitro has been well recognized. Thus, the effects of ascorbate on the efficacy of NTP is important to examine. NTP exposure dose-dependently killed MM cells, whereas MM cells tolerated 1 mM l-ascorbate. However, brief pre-treatment with a pharmacological dose (250-750 μM) of l-ascorbate immediately prior to NTP exposure significantly increased its cytotoxicity in a dose-dependent manner, which was inhibited by the iron chelator, deferoxamine. However, paradoxically, this potentiating effect of l-ascorbate was completely abolished by a prolonged 4 h pre-incubation with l-ascorbate (500 μM). MM cytotoxicity induced by NTP was associated with immediate oxidative stress evaluated by 2',7'-dichlorodihydrofluorecein diacetate, which was followed by an increase in the expression of the autophagosome marker, LC3B-II. In conclusion, MM can be a target for NTP treatment and l-ascorbate can increase or decrease its efficacy depending on the length of the pre-incubation period.

  2. Neutrophil migration across a cultured epithelial monolayer elicits a biphasic resistance response representing sequential effects on transcellular and paracellular pathways

    PubMed Central

    1992-01-01

    Migration of polymorphonuclear leukocytes across epithelia is a hallmark of many inflammatory disease states. Neutrophils traverse epithelia by migrating through the paracellular space and crossing intercellular tight junctions. We have previously shown (Nash, S., J. Stafford, and J.L. Madara. 1987. J. Clin. Invest. 80:1104-1113), that leukocyte migration across T84 monolayers, a model human intestinal epithelium, results in enhanced tight junction permeability--an effect quantitated by the use of a simple, standard electrical assay of transepithelial resistance. Here we show that detailed time course studies of the transmigration-elicited decline in resistance has two components, one of which is unrelated to junctional permeability. The initial decrease in resistance, maximal 5-13 min after initiation of transmigration, occurs despite inhibition of transmigration by an antibody to the common beta subunit of neutrophil beta 2 integrins, and is paralleled by an increase in transepithelial short-circuit current. Chloride ion substitution and inhibitor studies indicate that the early- phase resistance decline is not attributable to an increase in tight junction permeability but is due to decreased resistance across epithelial cells resulting from chloride secretion. Since T84 cells are accepted models for studies of the regulation of Cl- and water secretion, our results suggest that neutrophil transmigration across mucosal surfaces (for example, respiratory and intestinal tracts) may initially activate flushing of the surface by salt and water. Equally important, these studies, by providing a concrete example of sequential transcellular and paracellular effects on transepithelial resistance, highlight the fact that this widely used assay cannot simply be viewed as a direct functional probe of tight junction permeability. PMID:1577855

  3. Biphasic water splitting by osmocene

    PubMed Central

    Ge, Peiyu; Todorova, Tanya K.; Patir, Imren Hatay; Olaya, Astrid J.; Vrubel, Heron; Mendez, Manuel; Hu, Xile; Corminboeuf, Clémence; Girault, Hubert H.

    2012-01-01

    The photochemical reactivity of osmocene in a biphasic water-organic solvent system has been investigated to probe its water splitting properties. The photoreduction of aqueous protons to hydrogen under anaerobic conditions induced by osmocene dissolved in 1,2-dichloroethane and the subsequent water splitting by the osmocenium metal-metal dimer formed during H2 production were studied by electrochemical methods, UV-visible spectrometry, gas chromatography, and nuclear magnetic resonance spectroscopy. Density functional theory computations were used to validate the reaction pathways. PMID:22665787

  4. Biphasic dose response in low level light therapy - an update.

    PubMed

    Huang, Ying-Ying; Sharma, Sulbha K; Carroll, James; Hamblin, Michael R

    2011-01-01

    Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenosine triphosphate (ATP) and mitochondrial membrane potential show biphasic patterns, while others such as mitochondrial reactive oxygen species show a triphasic dose-response with two distinct peaks. The Janus nature of reactive oxygen species (ROS) that may act as a beneficial signaling molecule at low concentrations and a harmful cytotoxic agent at high concentrations, may partly explain the observed responses in vivo. Transcranial LLLT for traumatic brain injury (TBI) in mice shows a distinct biphasic pattern with peaks in beneficial neurological effects observed when the number of treatments is varied, and when the energy density of an individual treatment is varied. Further understanding of the extent to which biphasic dose responses apply in LLLT will be necessary to optimize clinical treatments.

  5. Multilevel Modeling of Item Position Effects

    ERIC Educational Resources Information Center

    Albano, Anthony D.

    2013-01-01

    In many testing programs it is assumed that the context or position in which an item is administered does not have a differential effect on examinee responses to the item. Violations of this assumption may bias item response theory estimates of item and person parameters. This study examines the potentially biasing effects of item position. A…

  6. Electron transport in zinc-blende wurtzite biphasic gallium nitride nanowires and GaNFETs

    DOE PAGES

    Jacobs, Benjamin W.; Ayres, Virginia M.; Stallcup, Richard E.; ...

    2007-10-19

    Two-point and four-point probe electrical measurements of a biphasic gallium nitride nanowire and current–voltage characteristics of a gallium nitride nanowire based field effect transistor are reported. The biphasic gallium nitride nanowires have a crystalline homostructure consisting of wurtzite and zinc-blende phases that grow simultaneously in the longitudinal direction. There is a sharp transition of one to a few atomic layers between each phase. Here, all measurements showed high current densities. Evidence of single-phase current transport in the biphasic nanowire structure is discussed.

  7. Effective Classroom-Management & Positive Teaching

    ERIC Educational Resources Information Center

    Sieberer-Nagler, Katharina

    2016-01-01

    This article offers practical information for primary teachers to become more knowledgable, skilled and effective in their work. Aspects of positive teaching and learning are explored. Innovative methods for transforming common classroom management struggles into opportunities for positive change and for changing negative behaviors into positive…

  8. Positive Behavior Interventions: The Issue of Sustainability of Positive Effects

    ERIC Educational Resources Information Center

    Yeung, Alexander Seeshing; Craven, Rhonda G.; Mooney, Mary; Tracey, Danielle; Barker, Katrina; Power, Anne; Dobia, Brenda; Chen, Zhu; Schofield, Jill; Whitefield, Phillip; Lewis, Timothy J.

    2016-01-01

    During the last decade, positive behavior interventions have resulted in improvement of school behavior and academic gains in a range of school settings worldwide. Recent studies identify sustainability of current positive behavior intervention programs as a major concern. The purpose of this article is to identify future direction for effective…

  9. Chitosan dressing promotes healing in third degree burns in mice: gene expression analysis shows biphasic effects for rapid tissue regeneration and decreased fibrotic signaling.

    PubMed

    Baxter, Ruth M; Dai, Tianhong; Kimball, Jess; Wang, Eugenia; Hamblin, Michael R; Wiesmann, William P; McCarthy, Simon J; Baker, Shenda M

    2013-02-01

    Burns are a significant health challenge and healing can result in scar formation. Chitosan, a derivative of chitin, has been used to promote wound healing. In this study we used gene expression profiling in a mouse model of full thickness cutaneous burn to assess the benefits of treating with a chitosan lactate dressing. Three days after wounding mice treated with chitosan showed increased expression of genes associated with formation of granulation tissue. At a later time point, seven days after wounding, genes that initially showed increased expression were now down-regulated, and there was increased expression of genes involved in remodeling suggesting that the chitosan treatment results in accelerated healing. Quantitative RT-PCR showed modulated mRNA levels for TGFβ1 by the chitosan dressing. TGFβ1 initially promotes healing but extended activity can result in scarring. Importantly we found that expression was elevated at day three, but decreased at day seven suggesting that chitosan treatment will not result in scar formation, and may even be beneficial in preventing scar formation. Additionally, the biphasic regulation of expression of TGFβ1 could be a powerful biomarker for future studies of the wound-healing potential of chitosan based and other treatments for burn wounds.

  10. Biphasic interaction of Triton detergents with the erythrocyte membrane.

    PubMed Central

    Trägner, D; Csordas, A

    1987-01-01

    Octylphenoxy polyoxyethylene ethers (Triton detergents) interact with the erythrocyte membrane in a biphasic manner, i.e. they stabilize erythrocytes against hypo-osmotic haemolysis at low concentrations (0.0001-0.01%, v/v), but become haemolytic at higher concentrations. This biphasic behaviour was demonstrated with Triton X-114, Triton X-100 and Triton X-102. However, a critical chain length is a prerequisite for the haemolytic effect, because Triton X-45, which differs from the other Tritons only by the shorter chain of the polyoxyethylene residue, does not exhibit this biphasic behaviour, but goes on protecting against osmotic rupture up to saturating concentrations. Even a 1% solution of Triton X-45 does not cause haemolysis. This structural specificity of Triton X-45, namely the lack of haemolysis and efficient stabilization against osmolysis even at higher concentrations of the detergent, is exhibited at 0 degree and 37 degrees C as well as at room temperature. Three conclusions are reached: (i) a critical chain length of the octylphenoxy polyoxyethylene ethers is required for the haemolytic effect; (ii) the different structural requirements would suggest that different mechanisms are responsible for the haemolytic and the stabilizing effect of amphiphilic substances; (iii) the results suggest that haemolysis is not caused simply by dissolution of the membrane by the detergent but is a rather more specific process. PMID:3446180

  11. Effect of gravity on vertical eye position.

    PubMed

    Pierrot-Deseilligny, C

    2009-05-01

    There is growing evidence that gravity markedly influences vertical eye position and movements. A new model for the organization of brainstem upgaze pathways is presented in this review. The crossing ventral tegmental tract (CVTT) could be the efferent tract of an "antigravitational" pathway terminating at the elevator muscle motoneurons in the third nerve nuclei and comprising, upstream, the superior vestibular nucleus and y-group, the flocculus, and the otoliths. This pathway functions in parallel to the medial longitudinal fasciculus pathways, which control vertical eye movements made to compensate for all vertical head movements and may also comprise the "gravitational" vestibular pathways, involved in the central reflection of the gravity effect. The CVTT could provide the upgaze system with the supplement of tonic activity required to counteract the gravity effect expressed in the gravitational pathway, being permanently modulated according to the static positions of the head (i.e., the instantaneous gravity vector) between a maximal activity in the upright position and a minimal activity in horizontal positions. Different types of arguments support this new model. The permanent influence of gravity on vertical eye position is strongly suggested by the vertical slow phases and nystagmus observed after rapid changes in hypo- or hypergravity. The chin-beating nystagmus, existing in normal subjects with their head in the upside-down position, suggests that gravity is not compensated for in the downgaze system. Upbeat nystagmus due to brainstem lesions, most likely affecting the CVTT circuitry, is improved when the head is in the horizontal position, suggesting that this circuitry is involved in the counteraction of gravity between the upright and horizontal positions of the head. In downbeat nystagmus due to floccular damage, in which a permanent hyperexcitation of the CVTT could exist, a marked influence of static positions of the head is also observed. Finally

  12. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    SciTech Connect

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

  13. Biphasic Effects of α-Asarone on Immobility in the Tail Suspension Test: Evidence for the Involvement of the Noradrenergic and Serotonergic Systems in Its Antidepressant-Like Activity

    PubMed Central

    Chellian, Ranjithkumar; Pandy, Vijayapandi; Mohamed, Zahurin

    2016-01-01

    Alpha (α)-asarone is one of the main psychoactive compounds, present in Acorus species. Evidence suggests that the α-asarone possess an antidepressant-like activity in mice. However, the exact dose-dependent effect of α-asarone and mechanism(s) involved in the antidepressant-like activity are not clear. The present study aimed to investigate the dose-dependent effect of α-asarone and the underlining mechanism(s) involved in the antidepressant-like activity of α-asarone in the mouse model of tail suspension test (TST). In this study, the acute effect of α-asarone per se at different doses (10–100 mg/kg, i.p.) on immobility in the TST was studied. Additionally, the possible mechanism(s) involved in the antidepressant-like effect of α-asarone was studied using its interaction with noradrenergic and serotonergic neuromodulators in the TST. The present results reveal that the acute treatment of α-asarone elicited biphasic responses on immobility such that the duration of the immobility time is significantly reduced at lower doses (15 and 20 mg/kg, i.p.) but increased at higher doses (50 and 100 mg/kg, i.p.) in the TST. Besides, α-asarone at higher doses (50 and 100 mg/kg, i.p.) significantly decreased the spontaneous locomotor activity. Moreover, pretreatment of mice with noradrenergic neuromodulators such as AMPT (100 mg/kg, i.p., a catecholamine synthesis inhibitor), prazosin (1 mg/kg, i.p., an α1-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α2-adrenoceptor antagonist) and with serotonergic neuromodulators such as PCPA (100 mg/kg, i.p., once daily for four consecutive days, a serotonin synthesis inhibitor,) and WAY100635 (0.1 mg/kg, s.c., a selective 5-HT1A receptor antagonist) significantly reversed the anti-immobility effect of α-asarone (20 mg/kg, i.p.). Taken together, our results suggest that the acute treatment with α-asarone elicited biphasic actions in the TST in which antidepressant-like effect was seen at relatively lower doses (15

  14. Micro-position sensor using faraday effect

    SciTech Connect

    McElfresh, Michael; Lucas, Matthew; Silveira, Joseph P.; Groves, Scott E.

    2007-02-27

    A micro-position sensor and sensing system using the Faraday Effect. The sensor uses a permanent magnet to provide a magnetic field, and a magneto-optic material positioned in the magnetic field for rotating the plane of polarization of polarized light transmitted through the magneto-optic material. The magnet is independently movable relative to the magneto-optic material so as to rotate the plane of polarization of the polarized light as a function of the relative position of the magnet. In this manner, the position of the magnet relative to the magneto-optic material may be determined from the rotated polarized light. The sensing system also includes a light source, such as a laser or LED, for producing polarized light, and an optical fiber which is connected to the light source and to the magneto-optic material at a sensing end of the optical fiber. Processing electronics, such as a polarimeter, are also provided for determining the Faraday rotation of the plane of polarization of the back-reflected polarized light to determine the position of the magnet relative to the sensing end of the optical fiber.

  15. Biphasic Dependence of Glioma Survival and Cell Migration on CD44 Expression Level.

    PubMed

    Klank, Rebecca L; Decker Grunke, Stacy A; Bangasser, Benjamin L; Forster, Colleen L; Price, Matthew A; Odde, Thomas J; SantaCruz, Karen S; Rosenfeld, Steven S; Canoll, Peter; Turley, Eva A; McCarthy, James B; Ohlfest, John R; Odde, David J

    2017-01-03

    While several studies link the cell-surface marker CD44 to cancer progression, conflicting results show both positive and negative correlations with increased CD44 levels. Here, we demonstrate that the survival outcomes of genetically induced glioma-bearing mice and of high-grade human glioma patients are biphasically correlated with CD44 level, with the poorest outcomes occurring at intermediate levels. Furthermore, the high-CD44-expressing mesenchymal subtype exhibited a positive trend of survival with increased CD44 level. Mouse cell migration rates in ex vivo brain slice cultures were also biphasically associated with CD44 level, with maximal migration corresponding to minimal survival. Cell simulations suggest that cell-substrate adhesiveness is sufficient to explain this biphasic migration. More generally, these results highlight the potential importance of non-monotonic relationships between survival and biomarkers associated with cancer progression.

  16. Effective Parenting: Positive Support for Families. Position Statement.

    ERIC Educational Resources Information Center

    National Association of School Psychologists, Bethesda, MD.

    Raising self-disciplined children is one challenge among many facing parents in American society today. Parents have little or no training in effective parenting, and they are often removed from extended families that have in the past been available to provide support and relief from the stress of child rearing. Discipline is often viewed as…

  17. The Biphasic Effects of Moderate Alcohol Consumption with a Meal on Ambiance-Induced Mood and Autonomic Nervous System Balance: A Randomized Crossover Trial

    PubMed Central

    Schrieks, Ilse C.; Stafleu, Annette; Kallen, Victor L.; Grootjen, Marc; Witkamp, Renger F.; Hendriks, Henk F. J.

    2014-01-01

    Background The pre-drinking mood state has been indicated to be an important factor in the mood effects of alcohol. However, for moderate alcohol consumption there are no controlled studies showing this association. Also, the mood effects of consuming alcohol combined with food are largely unknown. The aim of this study was to investigate the effects of moderate alcohol combined with a meal on ambiance-induced mood states. Furthermore effects on autonomic nervous system activity were measured to explore physiological mechanisms that may be involved in changes of mood state. Methods In a crossover design 28 women (age 18–45 y, BMI 18.5–27 kg/m2) were randomly allocated to 4 conditions in which they received 3 glasses of sparkling white wine (30 g alcohol) or alcohol-free sparkling white wine while having dinner in a room with either a pleasant or unpleasant created ambiance. Subjects filled out questionnaires (B-BAES, POMS and postprandial wellness questionnaire) at different times. Skin conductance and heart rate variability were measured continuously. Results Moderate alcohol consumption increased happiness scores in the unpleasant, but not in the pleasant ambiance. Alcohol consumption increased happiness and stimulation feelings within 1 hour and increased sedative feelings and sleepiness for 2.5 hour. Skin conductance was increased after alcohol within 1 hour and was related to happiness and stimulation scores. Heart rate variability was decreased after alcohol for 2 hours and was related to mental alertness. Conclusion Mood inductions and autonomic nervous system parameters may be useful to evaluate mood changes by nutritional interventions. Moderate alcohol consumption elevates happiness scores in an unpleasant ambiance. However, drinking alcohol during a pleasant mood results in an equally positive mood state. Trial Registration Clinicaltrials.gov NCT01426022. PMID:24465955

  18. Positive psychological effects of space missions

    NASA Astrophysics Data System (ADS)

    Ritsher, Jennifer Boyd; Ihle, Eva C.; Kanas, Nick

    2005-07-01

    Being in space is a powerful experience that can have an enduring, positive impact on the psychological well-being of astronauts and cosmonauts. We sought to examine the frequency, intensity and distribution of such salutogenic experiences among persons who have flown in space, using a questionnaire we developed based on the scientific literature and first person accounts. All participants reported positive effects of being in space, but the degree of change varied widely, and some experiences were particularly common. Three of our five predicted attitude behavior relationships were supported by the data. Response patterns did not vary according to demographics or time in space. Cluster analysis yielded two groups of participants. One group was generally more reactive and also placed a higher priority on perceptions of space than did the other group. We conclude that positive experiences are common among space travelers and seem to cluster into meaningful patterns that may be consequential for Mars missions. We consider the possible selection, training, and monitoring issues raised by our findings.

  19. Positive psychological effects of space missions.

    PubMed

    Ritsher, Jennifer Boyd; Ihle, Eva C; Kanas, Nick

    2005-01-01

    Being in space is a powerful experience that can have an enduring, positive impact on the psychological well-being of astronauts and cosmonauts. We sought to examine the frequency, intensity and distribution of such salutogenic experiences among persons who have flown in space, using a questionnaire we developed based on the scientific literature and first person accounts. All participants reported positive effects of being in space, but the degree of change varied widely, and some experiences were particularly common. Three of our five predicted attitude-behavior relationships were supported by the data. Response patterns did not vary according to demographics or time in space. Cluster analysis yielded two groups of participants. One group was generally more reactive and also placed a higher priority on perceptions of space than did the other group. We conclude that positive experiences are common among space travelers and seem to cluster into meaningful patterns that may be consequential for Mars missions. We consider the possible selection, training, and monitoring issues raised by our findings.

  20. Percutaneous biphasic electrical stimulation for treatment of obstructive sleep apnea syndrome.

    PubMed

    Hu, Lianggang; Xu, Xiaomei; Gong, Yongsheng; Fan, Xiaofang; Wang, Liangxing; Zhang, Jianhua; Zeng, Yanjun

    2008-01-01

    In this paper, we study the effect of stimulation of the genioglossus with percutaneous biphasic electrical pulses on patients with the obstructive sleep apnea syndrome (OSAS). The experiment was conducted in 22 patients clinically diagnosed with OSAS. The patients were monitored with polysomnography (PSG) in the trial. When the sleep apnea was detected, the genioglossus was stimulated with percutaneous biphasic electrical pulses that were automatically regulated by a microcontroller to achieve the optimal effect. The percutaneous biphasic electrical stimulation caused contraction of the genioglossus, forward movement of the tongue, and relieving of the glossopharyngeal airway obstruction. The SaO2, apnea time, hypoxemia time, and change of respiratory disturbance index (RDI) were compared in patients with treatment and without treatment. With percutaneous biphasic electrical stimulation of the genioglossus, the OSAS patients showed apnea time decreased (P < 0.01), RDI decreased (P < 0.01), and SaO2 increased (P < 0.01). No tissue injury or major discomfort was noticed during the trial. The stimulation of genioglossus with percutaneous biphasic electrical current pulse is an effective method for treating OSAS.

  1. Biphasic peptide amphiphile nanomatrix embedded with hydroxyapatite nanoparticles for stimulated osteoinductive response.

    PubMed

    Anderson, Joel M; Patterson, Jessica L; Vines, Jeremy B; Javed, Amjad; Gilbert, Shawn R; Jun, Ho-Wook

    2011-12-27

    Formation of the native bone extracellular matrix (ECM) provides an attractive template for bone tissue engineering. The structural support and biological complexity of bone ECM are provided within a composite microenvironment that consists of an organic fibrous network reinforced by inorganic hydroxyapatite (HA) nanoparticles. Recreating this biphasic assembly, a bone ECM analogous scaffold comprising self-assembling peptide amphiphile (PA) nanofibers and interspersed HA nanoparticles was investigated. PAs were endowed with biomolecular ligand signaling using a synthetically inscribed peptide sequence (i.e., RGDS) and integrated with HA nanoparticles to form a biphasic nanomatrix hydrogel. It was hypothesized the biphasic hydrogel would induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) and improve bone healing as mediated by RGDS ligand signaling within PA nanofibers and embedded HA mineralization source. Viscoelastic stability of the biphasic PA hydrogels was evaluated with different weight concentrations of HA for improved gelation. After demonstrating initial viability, long-term cellularity and osteoinduction of encapsulated hMSCs in different PA hydrogels were studied in vitro. Temporal progression of osteogenic maturation was assessed by gene expression of key markers. A preliminary animal study demonstrated bone healing capacity of the biphasic PA nanomatrix under physiological conditions using a critical size femoral defect rat model. The combination of RGDS ligand signaling and HA nanoparticles within the biphasic PA nanomatrix hydrogel demonstrated the most effective osteoinduction and comparative bone healing response. Therefore, the biphasic PA nanomatrix establishes a well-organized scaffold with increased similarity to natural bone ECM with the prospect for improved bone tissue regeneration.

  2. Therapeutic efficacy of endostatin exhibits a biphasic dose-response curve.

    PubMed

    Celik, Ilhan; Sürücü, Oguzkan; Dietz, Carsten; Heymach, John V; Force, Jeremy; Höschele, Iris; Becker, Christian M; Folkman, Judah; Kisker, Oliver

    2005-12-01

    We show here that recombinant endostatin protein has a biphasic effect on the inhibition of endothelial cell migration in vitro. In tumor-bearing animals, there is a similar biphasic effect on the inhibition of tumor growth and on circulating endothelial cells after once-daily s.c. injections. This biphasic effect is revealed as a U-shaped curve in which efficacy is optimal between very low and very high doses depending on the tumor type. This result may be applicable to other inhibitors of endothelial growth and to angiogenesis. Furthermore, these results have important implications for clinicians who administer angiogenesis inhibitors for cancer or other angiogenesis-dependent diseases. When these results are taken together with two previous reports of angiogenesis inhibitors with a U-shaped dose-response, they suggest that other regulators of endothelial growth may display a similar pattern.

  3. A biphasic scaffold based on silk and bioactive ceramic with stratified properties for osteochondral tissue regeneration.

    PubMed

    Li, Jiao Jiao; Kim, Kyungsook; Roohani-Esfahani, Seyed-Iman; Guo, Jin; Kaplan, David L; Zreiqat, Hala

    2015-07-14

    Significant clinical challenges encountered in the effective long-term treatment of osteochondral defects have inspired advancements in scaffold-based tissue engineering techniques to aid repair and regeneration. This study reports the development of a biphasic scaffold produced via a rational combination of silk fibroin and bioactive ceramic with stratified properties to satisfy the complex and diverse regenerative requirements of osteochondral tissue. Structural examination showed that the biphasic scaffold contained two phases with different pore morphologies to match the cartilage and bone segments of osteochondral tissue, which were joined at a continuous interface. Mechanical assessment showed that the two phases of the biphasic scaffold imitated the load-bearing behaviour of native osteochondral tissue and matched its compressive properties. In vitro testing showed that different compositions in the two phases of the biphasic scaffold could direct the preferential differentiation of human mesenchymal stem cells towards the chondrogenic or osteogenic lineage. By featuring simple and reproducible fabrication and a well-integrated interface, the biphasic scaffold strategy established in this study circumvented the common problems experienced with integrated scaffold designs and could provide an effective approach for the regeneration of osteochondral tissue.

  4. Fluency and positivity as possible causes of the truth effect.

    PubMed

    Unkelbach, Christian; Bayer, Myriam; Alves, Hans; Koch, Alex; Stahl, Christoph

    2011-09-01

    Statements' rated truth increases when people encounter them repeatedly. Processing fluency is a central variable to explain this truth effect. However, people experience processing fluency positively, and these positive experiences might cause the truth effect. Three studies investigated positivity and fluency influences on the truth effect. Study 1 found correlations between elicited positive feelings and rated truth. Study 2 replicated the repetition-based truth effect, but positivity did not influence the effect. Study 3 conveyed positive and negative correlations between positivity and truth in a learning phase. We again replicated the truth effect, but positivity only influenced judgments for easy statements in the learning phase. Thus, across three studies, we found positivity effects on rated truth, but not on the repetition-based truth effect: We conclude that positivity does not explain the standard truth effect, but the role of positive experiences for truth judgments deserves further investigation.

  5. Metal separations using aqueous biphasic partitioning systems

    SciTech Connect

    Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W.

    1996-05-01

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

  6. Biphasic Pulmonary Blastoma Associated with Cerebral Metastasis.

    PubMed

    Kilic, Dalokay; Yilmaz, Cem; Tepeoglu, Merih; Vural, Cigdem; Caner, Hakan

    2016-01-01

    Pulmonary blastoma is a very rare malignant tumor of the lungs. A biphasic pulmonary blastoma was histologically diagnosed by a characteristic finding as it was mainly constituted of immature tumor tissue that had both epithelial and mesenchymal components. We present a case of a 68-year-old man with biphasic pulmonary blastoma. The patient underwent cranial metastatectomy and left lung upper lobectomy. Although the tumor was resected, there was rapid metastasis to the cranial, liver, kidney and multiple bones. Although radiotherapy and chemotherapy were administrated, the patient died about 6 months postoperatively. Close follow-up and aggressive chemotherapy should be considered for such tumours. In the light of this case, the authors review the pathologic, clinical, radiological and therapeutic features of this very rare malignant lung tumor.

  7. Biomimetic biphasic scaffolds for osteochondral defect repair

    PubMed Central

    Li, Xuezhou; Ding, Jianxun; Wang, Jincheng; Zhuang, Xiuli; Chen, Xuesi

    2015-01-01

    The osteochondral defects caused by vigorous trauma or physical disease are difficult to be managed. Tissue engineering provides a possible option to regenerate the damaged osteochondral tissues. For osteochondral reconstruction, one intact scaffold should be considered to support the regeneration of both cartilage and subchondral bone. Therefore, the biphasic scaffolds with the mimic structures of osteochondral tissues have been developed to close this chasm. A variety of biomimetic bilayer scaffolds fabricated from natural or synthetic polymers, or the ones loading with growth factors, cells, or both of them make great progresses in osteochondral defect repair. In this review, the preparation and in vitro and/or in vivo verification of bioinspired biphasic scaffolds are summarized and discussed, as well as the prospect is predicted. PMID:26816644

  8. Comparison of single-biphasic versus sequential-biphasic shocks on defibrillation threshold in pigs.

    PubMed

    Csanadi, Z; Jones, D L; Wood, G K; Klein, G J

    1997-06-01

    Current generation implantable cardioverter defibrillators use monophasic, biphasic, or sequential pulse shocks, most of which truncate after a given time, dumping the remaining charge on the capacitor through an internal resistor. We hypothesized that having an additional current pathway, and delivering the majority of the remaining charge on a single capacitor to the two pathways using additional shock phases, would improve defibrillation efficacy. This hypothesis was tested by comparing DFTs using a simulated single capacitor, single-biphasic shock (two 5-ms pulses separated by 0.2 ms), delivered to coupled pairs of electrodes, to those using a sequential-biphasic shock (four 5-ms pulses separated by 0.2 ms) delivered to separate opposing electrodes, delivered from the same electrodes for both waveforms. In eight open-chest anesthetized pigs, four mesh electrodes (Medtronic TX-7, 6.5 cm2), were sutured on the epicardium of the anterior and posterior surfaces of each ventricle. Shocks were delivered from a 200-microF capacitor bank. Triplicate DFTs were obtained using each waveform in a randomized crossover design. Initial leading edge voltage (mean +/- SEM: 420 +/- 33 V vs 497 +/- 34 V; P < 0.05), initial peak current (4.8 +/- 0.4 A vs 13 +/- 1.1 A; P < 0.001), and delivered energy (16.9 +/- 2.6 J vs 30.4 +/- 5.3 J; P < 0.05) at the DFT were all significantly lower using sequential-biphasic shocks than those using single-biphasic shocks, respectively. We conclude that for direct heart defibrillation, it is worthwhile to combine sequential capability to biphasic shocks and deliver the remaining charge on the capacitor to the two different pathways.

  9. Cell–material interactions on biphasic polyurethane matrix

    PubMed Central

    Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-01-01

    Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  10. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  11. Biphasic effect of IL-1beta on the activity of argininosuccinate synthetase in Caco-2 cells. Involvement of nitric oxide production.

    PubMed

    Brasse-Lagnel, Carole; Lavoinne, Alain; Fairand, Alain; Vavasseur, Karine; Deniel, Nicolas; Husson, Annie

    2006-06-01

    The expression of the argininosuccinate synthetase gene (ASS), the limiting enzyme of arginine synthesis, was previously shown to be rapidly induced by a short-term (4 h) exposure to IL-1beta in Caco-2 cells [Biochimie, 2005, 403-409]. The present report shows that, by contrast, a long-term (24 h) exposure to IL-1beta inhibited the ASS activity despite an increase in both specific mRNA level and protein amount, demonstrating a post-translational effect. Concerning the mechanism involved, we demonstrate that the inhibiting effect is linked to the production of nitric oxide (NO) induced by IL-1beta. Indeed, the inhibiting effect of IL-1beta was totally blocked in the presence of l-NMMA, an inhibitor of the inducible nitric oxide synthase, or by culturing the cells in an arginine-deprived medium. Moreover, a decrease in the ASS activity was induced by culturing the cells in the presence of SNAP, a NO donor. Conversely, blocking the action of NO by antioxidant agents, the stimulatory effect of IL-1beta on ASS activity was restored, as measured at 24 h. Finally, such an inhibiting effect of NO on ASS activity may be related, at least in part, to S-nitrosylation of the protein. The physiological relevance of the antagonistic effects of IL-1beta and NO on ASS is discussed.

  12. Biphasic Affinity Chromatographic Approach for Deep Tyrosine Phosphoproteome Analysis.

    PubMed

    Deng, Zhenzhen; Dong, Mingming; Wang, Yan; Dong, Jing; Li, Shawn S-C; Zou, Hanfa; Ye, Mingliang

    2017-02-21

    Tyrosine phosphorylation (pTyr) is important for normal physiology and implicated in many human diseases, particularly cancer. Identification of pTyr sites is critical to dissecting signaling pathways and understanding disease pathologies. However, compared with serine/threonine phosphorylation (pSer/pThr), the analysis of pTyr at the proteome level is more challenging due to its low abundance. Here, we developed a biphasic affinity chromatographic approach where Src SH2 superbinder was coupled with NeutrAvidin affinity chromatography, for tyrosine phosphoproteome analysis. With the use of competitive elution agent biotin-pYEEI, this strategy can distinguish high-affinity phosphotyrosyl peptides from low-affinity ones, while the excess competitive agent is readily removed by using NeutrAvidin agarose resin in an integrated tip system. The excellent performance of this system was demonstrated by analyzing tyrosine phosphoproteome of Jurkat cells from which 3,480 unique pTyr sites were identified. The biphasic affinity chromatography method for deep Tyr phosphoproteome analysis is rapid, sensitive, robust, and cost-effective. It is widely applicable to the global analysis of the tyrosine phosphoproteome associated with tyrosine kinase signal transduction.

  13. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    PubMed

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (p<0.001) higher removal of nitrate was observed in the biphasic (42-63%) compared to the monophasic rain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (p<0.001), achieving up to 87% removal at a treatment C/N ratio of 2.0. This study demonstrates the importance of retention time, environmental conditions (i.e. saturated/unsaturated conditions), and availability of C substrate for bioremediation of pollutants, especially nitrates, in rain gardens.

  14. Activation of ganglion cells in wild-type and rd1 mouse retinas with monophasic and biphasic current pulses

    NASA Astrophysics Data System (ADS)

    Jensen, Ralph J.; Rizzo, Joseph F. III

    2009-06-01

    We and other research groups are designing an electronic retinal prosthesis to provide vision for patients who are blind due to photoreceptor degeneration. In this study, we examined the effect of stimulus waveform on the amount of current needed to activate retinal ganglion cells (RGCs) when the retinal neural network is stimulated. Isolated retinas of wild-type and rd1 mice were stimulated with cathodal and anodal monophasic current pulses of 1 ms duration and symmetric biphasic current pulses (1 ms per phase) delivered through an electrode that was located subretinally. For both wild-type and rd1 mouse retinas, cathodal current pulses were least effective in activating most RGCs. The median threshold current for a cathodal current pulse was 2.0-4.4 fold higher than the median threshold current for either an anodal or a biphasic current pulse. In wild-type mouse retinas, the median threshold current for activating RGCs with anodal current pulses was 23% lower than that with biphasic current pulses. In rd1 mouse retinas, the median threshold currents for anodal and biphasic current pulses were about the same. However, the variance in thresholds of rd1 RGCs for biphasic pulse stimulation was much smaller than for anodal pulse stimulation. Thus, a symmetric biphasic current pulse may be the best stimulus for activating the greatest number of RGCs in retinas devoid of photoreceptors.

  15. Remifentanil administration reveals biphasic phMRI temporal responses in rat consistent with dynamic receptor regulation

    PubMed Central

    Liu, Christina H.; Greve, Doug N.; Dai, Guangping; Marota, John J.A.; Mandeville, Joseph B.

    2007-01-01

    Many pharmacological stimuli influence multiple neurotransmitter systems in the brain, and the dynamics of the functional brain response can vary regionally. In this study, the temporal response of cerebral blood volume (CBV) was employed to spatially segment cerebral effects due to infusion of a potent mu-opioid receptor agonist. Repeated intravenous injection of 10 ug/kg remifentanil in rats caused reproducible regional positive, negative, and biphasic changes in CBV. Three temporal processes were identified in the cerebral response and analyzed within the framework of the general linear model. Firstly, a slow component identified CBV changes that were almost exclusively negative, and the spatial distribution was similar to the inhibition produced by morphine (200 ug/kg). The largest CBV reductions occurred in caudate, accumbens, ventral hippocampus, cingulate, and piriform cortex. Secondly, a more rapid temporal component corresponded primarily with a regional distribution of positive changes in CBV consistent with GABAergic inhibition of hippocampal interneurons and associated projections. Thirdly, a response with the dynamics of mean arterial blood pressure correlated positively with CBV changes in hypothalamus, consistent with a central mechanism for control of blood pressure. We propose that the dominant source of the temporal variance in signal is dynamic modulation of drug targets by receptor endocytosis, an established effect in vitro. These results suggest that the temporal response of fMRI signal reflects underlying neurobiological processes, so that temporal decomposition strategies may aid interpretation of pharmacological mechanisms by identifying interconnected regions or those associated with common neural targets and processes. PMID:17169578

  16. Soil decontamination using aqueous biphasic separation

    SciTech Connect

    Chaiko, D.J.; Mensah-Biney, R.; Gupta, D.

    1994-02-01

    This paper summarizes efforts to develop a biphasic extraction process for separating ultrafine particulate contaminants from soils having high amounts of silt and clay. This work has thus far dealt with the removal of refractory uranium particles from the soils at Fernald, Ohio. The separation process involves the selective partitioning of ultra-fine particles between two immiscible aqueous phases. The authors have conducted batch extraction studies and are now beginning to scaleup the process for pilot-plant testing at Argonne National Laboratory (ANL). The results of these extraction studies are discussed.

  17. Conduction block in myelinated axons induced by high-frequency (kHz) non-symmetric biphasic stimulation

    PubMed Central

    Zhao, Shouguo; Yang, Guangning; Wang, Jicheng; Roppolo, James R.; de Groat, William C.; Tai, Changfeng

    2015-01-01

    This study used the Frankenhaeuser–Huxley axonal model to analyze the effects of non-symmetric waveforms on conduction block of myelinated axons induced by high-frequency (10–300 kHz) biphasic electrical stimulation. The results predict a monotonic relationship between block threshold and stimulation frequency for symmetric waveform and a non-monotonic relationship for non-symmetric waveforms. The symmetric waveform causes conduction block by constantly activating both sodium and potassium channels at frequencies of 20–300 kHz, while the non-symmetric waveforms share the same blocking mechanism from 20 kHz up to the peak threshold frequency. At the frequencies above the peak threshold frequency the non-symmetric waveforms block axonal conduction by either hyperpolarizing the membrane (if the positive pulse is longer) or depolarizing the membrane (if the negative pulse is longer). This simulation study further increases our understanding of conduction block in myelinated axons induced by high-frequency biphasic electrical stimulation, and can guide future animal experiments as well as optimize stimulation parameters that might be used for electrically induced nerve block in clinical applications. PMID:26217217

  18. Aqueous biphasic extraction process with pH and particle control

    DOEpatents

    Chaiko, David J.; Mensah-Biney, R.

    1995-01-01

    A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica from kaolin clay.

  19. Aqueous biphasic extraction process with pH and particle control

    DOEpatents

    Chaiko, D.J.; Mensah-Biney, R.

    1995-05-02

    A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica from kaolin clay. 2 figs.

  20. Biphasic Effects of Nitric Oxide Radicals on Radiation-Induced Lethality and Chromosome Aberrations in Human Lung Cancer Cells Carrying Different p53 Gene Status

    SciTech Connect

    Su Xiaoming; Takahashi, Akihisa; Guo Guozhen; Mori, Eiichiro; Okamoto, Noritomo; Ohnishi, Ken; Iwasaki, Toshiyasu; Ohnishi, Takeo

    2010-06-01

    Purpose: The aim of this study was to clarify the effects of nitric oxide (NO) on radiation-induced cell killing and chromosome aberrations in two human lung cancer cell lines with a different p53 gene status. Methods and Materials: We used wild-type (wt) p53 and mutated (m) p53 cell lines that were derived from the human lung cancer H1299 cell line, which is p53 null. The wtp53 and mp53 cell lines were generated by transfection of the appropriate p53 constructs into the parental cells. Cells were pretreated with different concentrations of isosorbide dinitrate (ISDN) (an NO donor) and/or 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) (an NO scavenger) and then exposed to X-rays. Cell survival, apoptosis, and chromosome aberrations were scored by use of a colony-forming assay, Hoechst 33342 staining assay and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP [deoxyuridine triphosphate] nick end labeling) assay, and chromosomal banding techniques, respectively. Results: In wtp53 cells the induction of radioresistance and the inhibition of apoptosis and chromosome aberrations were observed in the presence of ISDN at low 2- to 10-{mu}mol/L concentrations before X-irradiation. The addition of c-PTIO and ISDN into the culture medium 6 h before irradiation almost completely suppressed these effects. However, at high concentrations of ISDN (100-500 {mu}mol/L), clear evidence of radiosensitization, enhancement of apoptosis, and chromosome aberrations was detected. However, these phenomena were not observed in mp53 cells at either concentration range with ISDN. Conclusions: These results indicate that low and high concentrations of NO radicals can choreograph inverse radiosensitivity, apoptosis, and chromosome aberrations in human lung cancer cells and that NO radicals can affect the fate of wtp53 cells.

  1. Two culture systems showing a biphasic effect on ovine embryo development from the 1-2 cell stage to hatched blastocysts.

    PubMed

    Ledda, S; Bogliolo, L; Leoni, G; Loi, P; Cappai, P; Naitana, S

    1995-01-01

    This study compared the effect of using either CZB or TCM 199 media on both the development of 1-2 cell ovine embryos from superovulated ewes to the blastocyst stage (Experiment 1), and the hatching process of ovine blastocysts developed in vitro (Experiment 2). For the first 5 d, the CZB medium showed higher rates of embryo development than the TCM 199 medium (p < 0.001). The embryos reaching the > 16 cell stage were 79 vs 52% and 74 vs 20% with or without an oviductal monolayer, respectively, and those reaching the blastocyst stage were 71 vs 46% and 46 vs 13% with or without cells. The CZB medium was less able to support the hatching process of the blastocysts obtained in the first experiment than was the TCM-199 medium + 10% FCS (fetal calf serum) with cells (31 vs 92%; p < 0.001) or without cells (13 vs 66%; p < 0.001). No blastocysts completely escaped from the zona pellucida (ZP) in the CZB medium compared with 80 and 61% in the TCM 199 medium with or without cells, respectively. In Experiment 3, 47% of the blastocysts migrated through the artificial opening of the ZP and hatched completely. After 24 h of culture in the CZB medium, however, they showed blastocoelic cavity breakdown. During the preliminary cleavages, the ovine embryos developed better in CZB medium than in TCM 199, but the latter was more efficient in promoting the hatching process of the blastocysts.

  2. Physiological Effects of Positive Pressure Ventilation.

    DTIC Science & Technology

    1992-05-01

    spontaneous breath (Banner, et al., 1990). This "stacking" of mechanical on spontaneous breaths could increase the peak inflation, airway , and intrapleural...J., & Gottfried, S. B. (1990). Continuous positive airway pressure reduces work of breathing and dyspnea during weaning from mechanical ventilation in...insufficiency is caused by numerous physiological aberrations, some of which can be reversed or improved by mechanical respiratory support, thus

  3. Biphasic Effect of Basic Fibroblast Growth Factor on Anterior Pituitary Folliculostellate TtT/GF Cell Coupling, and Connexin 43 Expression and Phosphorylation.

    PubMed

    Vitale, M L; Barry, A

    2015-10-01

    Basic fibroblast growth factor (bFGF) is a mitogenic and differentiating cytokine. In the anterior pituitary, folliculostellate (FS) cells constitute the major source of bFGF. bFGF affects endocrine cell proliferation and secretion in the anterior pituitary. In addition, bFGF increases its own expression by acting directly on FS cells. FS cell Cx43-mediated gap junction intercellular communication allows the establishment of an intrapituitary network for the transmission of information. In the present study, we assessed how bFGF regulates FS cell coupling. Time course studies were carried out on the FS cell line TtT/GF. Short-term bFGF treatment induced a transient cell uncoupling and the phosphorylation in Ser368 of membrane-bound Cx43 without modifying Cx43 levels. We demonstrated the involvement of the protein kinase C (PKC) isoform α in the phosphorylation of Cx43 in S368. Moreover, we showed that bFGF induced PKCα activation by stimulating its expression, phosphorylation and association with the plasma membrane. The long-term incubation with bFGF increased TtT/GF cell coupling, total Cx43 levels and Cx43 accumulation at the cell membrane of cytoplasmic projections. The Cx43 level increase was a result of the stimulation of Cx43 gene transcription as mediated by the extracellular-regulated kinase 1/2 signalling pathway. Taken together, the data show that bFGF modulates TtT/GF cell coupling by activating different pathways that lead to opposite effects on Cx43 phosphorylation and expression depending on the duration of the exposure of the cells to bFGF. A short-term bFGF exposure reduces cell-to-cell communication as a mean of desynchronising FS cells. By contrast, long-term exposure to bFGF enhances cell-to-cell communication and facilitates coordination among FS cells.

  4. Biphasic effect of duodenal ulcerogens cysteamine (C), mepirizole (M) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropryridine (MPTP) on gastric emptying in the rat

    SciTech Connect

    Pihan, G.; Kline, T.J.; Szabo, S.

    1986-03-01

    The effect of acute or chronic administration of duodenal ulcerogens on gastric emptying (GE) of a liquid meal was investigated. In Sprague-Dawley rats (150-200g) 2 ml of /sup 51/Cr in 2% dextrose (5000 CPM) was given intragastrically and the GE half life was established as 7.6 min (controls). In acute experiments, C (30mg/100g), M (40mg/100g) or MPTP (4mg/100g) injected subcutaneously all delayed GE at 1, 2, 4, 8 and 24 hr by 15-77%. Maximal GE delay (p<0.05) by 77, 48 or 71% was found 1, 1 or 2 hr after C, M or MPTP, respectively. In chronic experiments, C (22mg/100g) was given x3 on the first day and once daily (25mg/100g) for 3 or 10 additional days. M (20mg/100g) once daily and MPTP (4mg/100g) x3 daily were given for 4 or 11 days. GE was measured on the 5th and 12th day. Chronically, MPTP accelerated GE by 63 and 31% at 5 and 12 days (p<0.05) and C and M did not change GE. The severity of duodenal ulcers correlated (p<0.05) with the amount of /sup 51/Cr remaining in the stomach: r=-0.68, -0.74 and -0.70 after C, M and MPTP, respectively. Acute administration of duodenal ulcerogens delay GE in rats. Chronic treatment with duodenal ulcerogens either accelerates or does not change GE. The most severe chronic ulcers exhibit the most rapid emptying. The authors data suggest that rapid GE might be a secondary rather than a primary alteration in duodenal ulceration.

  5. Biphasic cell responses on laterally mobile films

    NASA Astrophysics Data System (ADS)

    Kourouklis, Andreas; Lerum, Ronald; Bermudez, Harry

    2013-03-01

    The engineering of polymer surfaces or matrices that are capable of controlling cell adhesion has been widely explored. In nearly all of these works, the polymer chains (and ligands) are chemically attached to the underlying substrate, and therefore these systems are inherently static. By contrast, cellular environments such as the extracellular matrix (ECM) are dynamic and remodeled by biochemical reactions and biophysical forces. Borrowing this concept from Nature, we created polymer films by an interfacial self-assembly process, whereby individual chains can exhibit lateral mobility (in-plane diffusive motion). NIH 3T3 fibroblasts seeded on such RGD-presenting polymer films show biphasic responses in spreading and adhesion strength to lateral mobility, with a minimal response for intermediate mobility values. Futhermore, preliminary immuno-staining experiments reveal that the total area of focal adhesions demonstrates a similar biphasic trend to the cellular-scale behaviors. In contrast, actin filaments or stress fibers appear to be unaffected by the substrate lateral mobility. These results show that lateral mobility is an important, although not fully explored aspect of mechano-sensing by cells, and can potentially give new perspectives on cell-ECM interactions. National Science Foundation

  6. Biphasic functions of the kinase-defective Ephb6 receptor in cell adhesion and migration.

    PubMed

    Matsuoka, Hiroshi; Obama, Hiroya; Kelly, Meghan L; Matsui, Toshimitsu; Nakamoto, Masaru

    2005-08-12

    EphB6 is a unique member in the Eph family of receptor tyrosine kinases in that its kinase domain contains several alterations in conserved amino acids and is catalytically inactive. Although EphB6 is expressed both in a variety of embryonic and adult tissues, biological functions of this receptor are largely unknown. In the present study, we examined the function of EphB6 in cell adhesion and migration. We demonstrated that EphB6 exerted biphasic effects in response to different concentrations of the ephrin-B2 ligand; EphB6 promoted cell adhesion and migration when stimulated with low concentrations of ephrin-B2, whereas it induced repulsion and inhibited migration upon stimulation with high concentrations of ephrin-B2. A truncated EphB6 receptor lacking the cytoplasmic domain showed monophasic-positive effects on cell adhesion and migration, indicating that the cytoplasmic domain is essential for the negative effects. EphB6 is constitutively associated with the Src family kinase Fyn. High concentrations of ephrin-B2 induced tyrosine phosphorylation of EphB6 through an Src family kinase activity. These results indicate that EphB6 can both positively and negatively regulate cell adhesion and migration, and suggest that tyrosine phosphorylation of the receptor by an Src family kinase acts as the molecular switch for the functional transition.

  7. Biphasic microtiter method for campylobacter recovery and enumeration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We developed a biphasic method for recovery and enumeration of campylobacters. The biphasic system was composed of 96-well microtiter plates containing Campy-Line Agar (CLA) prepared 2X for all ingredients except for 1X agar (0.1 ml per well). Samples of pure Campylobacter spp. isolates, post-chi...

  8. Biphasic Electrical Field Stimulation Aids in Tissue Engineering of Multicell-Type Cardiac Organoids

    PubMed Central

    Chiu, Loraine L.Y.; Iyer, Rohin K.; King, John-Paul

    2011-01-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence. PMID:18783322

  9. Biphasic electrical field stimulation aids in tissue engineering of multicell-type cardiac organoids.

    PubMed

    Chiu, Loraine L Y; Iyer, Rohin K; King, John-Paul; Radisic, Milica

    2011-06-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence.

  10. Somatopsychic Effects of Hypertension: A Theoretical Position.

    ERIC Educational Resources Information Center

    Gibson, Gail S.; Benson, Frank B., III

    1979-01-01

    As a consequence of somatic changes patients may suffer profound, indirect, and direct psychological effects in addition to the more direct biological ones. In order to prepare patients for living with new circumstances and feelings created by illness, intervention stragegies should address somatopsychic effects as well as others. (Author)

  11. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    SciTech Connect

    K. Osseo-Asare; X. Zeng

    2002-01-01

    The objective of this research project is to develop an aqueous biphase extraction process for the treatment of fine coals. Aqueous biphase extraction is an advanced separation technology that relies on the ability of an aqueous system consisting of a water-soluble polymer and another component, e.g., another polymer, an inorganic salt, or a nonionic surfactant, to separate into two immiscible aqueous phases. The principle behind the partition of solid particles in aqueous biphase systems is the physicochemical interaction between the solid surface and the surrounding liquid solution. In order to remove sulfur and mineral matter from fine coal with aqueous biphasic extraction, it is necessary to know the partitioning behavior of coal, as well as the inorganic mineral components. Therefore, in this research emphasis was placed on the partitioning behavior of fine coal particles as well as model fine inorganic particles in aqueous biphase systems.

  12. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    SciTech Connect

    K. Osseo-Asare; X. Zeng

    2001-06-30

    Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behaviors of hematite in the dextran (Dex)/Triton X-100 (TX100) and polyethylene glycol (PEG)/dextran systems were investigated and the effects of some ionic surfactants on solid partition were studied. In both biphase systems, the particles stayed in the bottom dextran-rich phase under all pH conditions. This behavior is attributable to the fact that the hydrophilic oxide particles prefer the more hydrophilic bottom phase. Also, the strong favorable interaction between dextran and ferric oxide facilitates the dispersion of the solids in the polysaccharide-rich phase. In the Dex/TX100 system, addition of sodium dodecylsulfate (SDS) or potassium oleate had no effect on the solid partition; on the other hand, addition of dodecyltrimethylammonium bromide (DTAB) transferred the particles to the top phase or interface at high pH values. In the PEG/Dex system, the preferred location of hematite remained the bottom phase in the presence of either SDS or DTAB. The effects of anionic surfactants on the partition behavior are attributable to the fact that they are not able to replace the strongly adsorbed polysaccharide layer on the ferric oxide surface. The results with the cationic surfactant are due to electrostatic interaction between the cationic surfactant and the charged surface of the solid particles. The difference in solids partitioning in the two systems is the result of the different distribution of DTAB in these systems. In the Dex/TX100 system, DTAB prefers the top surfactant-rich phase, while it concentrates in the bottom phase in the PEG/dextran system.

  13. High-side Digitally Current Controlled Biphasic Bipolar Microstimulator

    PubMed Central

    Hanson, Timothy L.; Ómarsson, Björn; O'Doherty, Joseph E.; Peikon, Ian D.; Lebedev, Mikhail; Nicolelis, Miguel AL.

    2012-01-01

    Electrical stimulation of nervous tissue has been extensively used as both a tool in experimental neuroscience research and as a method for restoring of neural functions in patients suffering from sensory and motor disabilities. In the central nervous system, intracortical microstimulation (ICMS) has been shown to be an effective method for inducing or biasing perception, including visual and tactile sensation. ICMS also holds promise for enabling brain-machine-brain interfaces (BMBIs) by directly writing information into the brain. Here we detail the design of a high-side, digitally current-controlled biphasic, bipolar microstimulator, and describe the validation of the device in vivo. As many applications of this technique, including BMBIs, require recording as well as stimulation, we pay careful attention to isolation of the stimulus channels and parasitic current injection. With the realized device and standard recording hardware - without active artifact rejection - we are able to observe stimulus artifacts of less than 2 ms in duration. PMID:22328184

  14. Surface modification of biphasic calcium phosphate bioceramic powders

    NASA Astrophysics Data System (ADS)

    Yang, W. Z.; Zhou, D. L.; Yin, G. F.; Li, G. D.

    2008-11-01

    Biphasic calcium phosphate (BCP)/poly L-lactide (PLLA) biocomposite is proven to be a promising bone graft material or scaffold for bone tissue engineering. To improve the interfacial compatibility of BCP bioceramic with biopolymer-PLLA, BCP powders were surface-modified in different condition to graft polymer groups onto the surface of the BCP powders. L-lactide and L-lactic acid (LA) oligomer were used to modify the BCP surface with stannous octanoate (Sn(Oct) 2) and stannous chloride (SnCl 2) as catalyst, respectively. Results show that the surface modification effect is obvious and the amount of grafted organic group is above 6.5 wt.%. Sn(Oct) 2 and SnCl 2 are the optimal catalysts for the surface grafting reaction of L-lactide and L-LA oligomer, respectively. The surface grafting slightly increase the particle size of BCP powders and reduce the tendency for their agglomeration.

  15. High-side digitally current controlled biphasic bipolar microstimulator.

    PubMed

    Hanson, Timothy L; Ómarsson, Björn; O'Doherty, Joseph E; Peikon, Ian D; Lebedev, Mikhail A; Nicolelis, Miguel A L

    2012-05-01

    Electrical stimulation of nervous tissue has been extensively used as both a tool in experimental neuroscience research and as a method for restoring of neural functions in patients suffering from sensory and motor disabilities. In the central nervous system, intracortical microstimulation (ICMS) has been shown to be an effective method for inducing or biasing perception, including visual and tactile sensation. ICMS also holds promise for enabling brain-machine-brain interfaces (BMBIs) by directly writing information into the brain. Here we detail the design of a high-side, digitally current-controlled biphasic, bipolar microstimulator, and describe the validation of the device in vivo. As many applications of this technique, including BMBIs, require recording as well as stimulation, we pay careful attention to isolation of the stimulus channels and parasitic current injection. With the realized device and standard recording hardware-without active artifact rejection-we are able to observe stimulus artifacts of less than 2 ms in duration.

  16. Recycling nanoparticle catalysts without separation based on a pickering emulsion/organic biphasic system.

    PubMed

    Liu, Huifang; Zhang, Zhiming; Yang, Hengquan; Cheng, Fangqin; Du, Zhiping

    2014-07-01

    A conceptually novel methodology is explored for in situ recycling of nanoparticle catalysts based on transforming a conventional organic/aqueous biphasic system into a Pickering emulsion/organic biphasic system (PEOBS). The suggested PEOBS exists as two phases, with the nanoparticle catalyst "anchored" in the Pickering emulsion phase, but is "continuous" between the organic phase and the continuous phase of the Pickering emulsion. Aqueous hydrogenations are used to evaluate the reaction performances of PEOBS, and the underlying principles of PEOBS are preliminarily elaborated. The unique properties of PEOBS lead to many intriguing findings, which are unlikely to be achieved in the reported biphasic systems. PEOBS exhibits more than a fourfold enhancement in catalysis efficiency in comparison with a conventional biphasic system. Impressively, PEOBS enables the organic product to be facilely isolated through simple decantation and the nanoparticle catalyst can be recycled in situ without the need for "separation". Its recycling effectiveness is justified by ten reaction cycles without significant catalyst loss. The simple protocol, in conjunction with the stability to simultaneously achieve high catalysis efficiency and excellent catalyst recyclability, makes PEOBS a promising methodology to develop more sustainable nanocatalysis.

  17. Biphasic Dose Response in Low Level Light Therapy – An Update

    PubMed Central

    Huang, Ying-Ying; Sharma, Sulbha K; Carroll, James; Hamblin, Michael R

    2011-01-01

    Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenosine triphosphate (ATP) and mitochondrial membrane potential show biphasic patterns, while others such as mitochondrial reactive oxygen species show a triphasic dose-response with two distinct peaks. The Janus nature of reactive oxygen species (ROS) that may act as a beneficial signaling molecule at low concentrations and a harmful cytotoxic agent at high concentrations, may partly explain the observed responses in vivo. Transcranial LLLT for traumatic brain injury (TBI) in mice shows a distinct biphasic pattern with peaks in beneficial neurological effects observed when the number of treatments is varied, and when the energy density of an individual treatment is varied. Further understanding of the extent to which biphasic dose responses apply in LLLT will be necessary to optimize clinical treatments. PMID:22461763

  18. Effectively Promoting Positive Character Traits in Children.

    ERIC Educational Resources Information Center

    Amish, Celeste; Markowski, Tracey; Woolwine, Katrina

    This action research project implemented strategies for effectively promoting attitude and values to elicit good character in children. The targeted population consisted of first and third grade students in three schools in a middle class community in northern Illinois. The lack of respect and poor moral values contributed to the data that are…

  19. Effects of the "Positive Action" Program on Indicators of Positive Youth Development among Urban Youth

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Vuchinich, Samuel; Ji, Peter; DuBois, David L.; Acock, Alan; Bavarian, Niloofar; Day, Joseph; Silverthorn, Naida; Flay, Brian R.

    2016-01-01

    This study evaluated effects of "Positive Action," a school-based social-emotional and character development intervention, on indicators of positive youth development (PYD) among a sample of low-income, ethnic minority youth attending 14 urban schools. The study used a matched-pair, cluster-randomized controlled design at the school…

  20. Biphasic Role of Calcium in Mouse Sperm Capacitation Signaling Pathways

    PubMed Central

    Alvau, Antonio; Escoffier, Jessica; Krapf, Dario; Sánchez-Cárdenas, Claudia; Salicioni, Ana M.; Darszon, Alberto; Visconti, Pablo E.

    2016-01-01

    Mammalian sperm acquire fertilizing ability in the female tract in a process known as capacitation. At the molecular level, capacitation is associated with up-regulation of a cAMP-dependent pathway, changes in intracellular pH, intracellular Ca2+ and an increase in tyrosine phosphorylation. How these signaling systems interact during capacitation is not well understood. Results presented in this study indicate that Ca2+ ions have a biphasic role in the regulation of cAMP-dependent signaling. Media without added Ca2+ salts (nominal zero Ca2+) still contain micromolar concentrations of this ion. Sperm incubated in this medium did not undergo PKA activation or the increase in tyrosine phosphorylation suggesting that these phosphorylation pathways require Ca2+. However, chelation of the extracellular Ca2+ traces by EGTA induced both cAMP-dependent phosphorylation and the increase in tyrosine phosphorylation. The EGTA effect in nominal zero Ca2+ media was mimicked by two calmodulin antagonists, W7 and calmidazolium, and by the calcineurin inhibitor cyclosporine A. These results suggest that Ca2+ ions regulate sperm cAMP and tyrosine phosphorylation pathways in a biphasic manner and that some of its effects are mediated by calmodulin. Interestingly, contrary to wild type mouse sperm, sperm from CatSper1 KO mice underwent PKA activation and an increase in tyrosine phosphorylation upon incubation in nominal zero Ca2+ media. Therefore, sperm lacking Catsper Ca2+ channels behave as wild-type sperm incubated in the presence of EGTA. This latter result suggests that Catsper transports the Ca2+ involved in the regulation of cAMP-dependent and tyrosine phosphorylation pathways required for sperm capacitation. PMID:25597298

  1. Tissue engineering of biphasic joint cartilage transplants.

    PubMed

    Kreklau, B; Sittinger, M; Mensing, M B; Voigt, C; Berger, G; Burmester, G R; Rahmanzadeh, R; Gross, U

    1999-09-01

    In isolated posttraumatic or idiopathic joint defects the chondral layers and adjacent subchondral spongy bone are usually destructed. For regeneration we suggest the in vitro formation of a cartilage-coated biomaterial carriers (biphases) in order to fill the correspondingjoint defects. In this study Biocoral, a natural coralline material made of calcium carbonate, and calcite, a synthetic calcium carbonate, were used as supports for the cultivation of bovine chondrocytes in a three-dimensional polymer fleece. The cell-polymer-structure was affixed to the biomaterial with a fibrin-cell-solution. The artificial cartilage formed a new matrix and fused with the underlying biomaterial. The results indicate a promising technical approach to anchor tissue engineered cartilage in joint defects.

  2. Invariance of the magnetic behavior and AMI in ferromagnetic biphase films with distinct non-magnetic metallic spacers

    NASA Astrophysics Data System (ADS)

    Silva, E. F.; Gamino, M.; Andrade, A. M. H. de; Vázquez, M.; Correa, M. A.; Bohn, F.

    2017-02-01

    We investigate the quasi-static magnetic, magnetotransport, and dynamic magnetic properties in ferromagnetic biphase films with distinct non-magnetic metallic spacer layers. We observe that the nature of the non-magnetic metallic spacer material does not have significant influence on the overall biphase magnetic behavior, and, consequently, on the magnetotransport and dynamic magnetic responses. We focus on the magnetoimpedance effect and verify that the films present asymmetric magnetoimpedance effect. Moreover, we explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the probe current frequency in order to achieve higher sensitivity values. The invariance of the magnetic behavior and the asymmetric magnetoimpedance effect in ferromagnetic biphase films with distinct non-magnetic metallic spacers place them as promising candidates for probe element and open possibilities to the development of lower-cost high sensitivity linear magnetic field sensor devices.

  3. Antibacterial activity evaluation of bioactive glass and biphasic calcium phosphate nanopowders mixtures

    NASA Astrophysics Data System (ADS)

    Nazemi, Zahra; Mehdikhani-Nahrkhalaji, Mehdi; Haghbin-Nazarpak, Masoumeh; Staji, Hamid; Kalani, Mohammad Mehdi

    2016-12-01

    The aim of this work was to evaluate the antibacterial activity of bioactive glass (BG) and biphasic calcium phosphate (BCP) nanopowders mixtures for the first time. 37S BG and BCP (50% HA-50% β-TCP) nanopowders were prepared via sol-gel technique. Characterization techniques such as X-ray diffraction, scanning electron microscopy, transition electron microscopy, and X-ray fluorescent. The antibacterial activity was studied using Escherichia coli and Salmonella typhi as gram-negative, and Staphylococcus aureus as gram-positive bacteria. The antibacterial effect of BG, BCP nanopowders, and their mixtures was evaluated at different concentrations. The 37S BG nanopowders showed minimum bactericidal concentration at 25 mg/ml. At broth concentrations below 300 mg/ml, BCP showed no antibacterial activity. BCP and BG nanopowders mixture (M2) with 60/40 ratio of BCP/BG showed noticeable antibacterial effect. It was concluded that BCP and 37S BG nanopowders mixture could be used as a good candidate for dental and orthopedic applications.

  4. The better, the bigger: The effect of graded positive performance feedback on the reward positivity.

    PubMed

    Frömer, Romy; Stürmer, Birgit; Sommer, Werner

    2016-02-01

    In this study on skill acquisition in a computerized throwing task, we examined the effect of graded correct-related performance feedback on the reward positivity of the event-related brain potential (ERP). Theories of reinforcement learning predict effects of reward magnitude and expectancy on the reward prediction error. The later is supposed to be reflected in reward positivity, a fronto-central ERP component. A sample of 68 participants learned to throw at a beamer-projected target disk while performance accuracy, displayed as the place of impact of the projectile on the target, served as graded feedback. Effects of performance accuracy in successful trials, hit frequency, and preceding trial performance on reward positivity were analyzed simultaneously on a trial-by-trial basis by means of linear mixed models. In accord with previous findings, reward positivity increased with feedback about more accurate performance. This relationship was not linear, but cubic, with larger impact of feedback towards the end of the accuracy distribution. In line with being a measure of expectancy, the reward positivity decreased with increasing hit frequency and was larger after unsuccessful trials. The effect of hit frequency was more pronounced following successful trials. These results indicate a fast trial-by-trial adaptation of expectation. The results confirm predictions of reinforcement learning theory and extend previous findings on reward magnitude to the area of complex, goal directed skill acquisition.

  5. Vorticity banding in biphasic polymer blends.

    PubMed

    Caserta, Sergio; Guido, Stefano

    2012-11-27

    Pattern formation under the action of flow is a subject of considerable scientific interest with applications going from microfluidics to granular materials. Here, we present a systematic investigation of shear-induced banding in confined biphasic liquid-liquid systems, i.e., formation of alternating regions of high and low volume fraction of droplets in a continuous phase (shear bands). This phenomenon is investigated in immiscible polymer blends sheared in a sliding parallel plate flow cell. Starting from a spatially uniform distribution of droplets, the formation of bands aligned along the flow direction is observed, eventually leading to an almost complete separation between droplet-rich and continuous phase regions. The initial band size is related to the gap dimension; the merging of bands and consequent spacing reduction has also been observed for long times. Shear banding is only observed when the viscosity of the dispersed phase is lower as compared to the continuous phase and in a limited range of the applied shear rate. Rheological measurements show that band formation is associated with a viscosity decrease with respect to the homogeneous case, thus implying that system microstructure is somehow evolving toward reduced viscous dissipation under flow.

  6. Bi-phasic growth of Listeria monocytogenes in chemically defined medium at low temperatures.

    PubMed

    Tyrovouzis, Nikolaos A; Angelidis, Apostolos S; Stoforos, Nikolaos G

    2014-09-01

    The present work reports a novel observation regarding the growth of L. monocytogenes in modified Welshimer's broth (MWB) at low temperatures. Specifically, the direct monitoring of the growth of L. monocytogenes Scott A using plate count data revealed that the pathogen displays a bi-phasic growth pattern in MWB at 7 °C. This bi-phasic growth pattern is masked (not observed) when optical density (OD) measurements are used to monitor growth due to the inability of OD readings to detect L. monocytogenes population density increases up to 10(7) CFU/mL. This bi-phasic growth phenomenon was further investigated as a function of growth temperature (4 °C, 7 °C, 10 °C, 14 °C and 18 °C), medium composition (by altering the MWB composition by ten-fold increases in different sets of medium constituents), inoculum level (10(2), 10(3), 10(4), 10(5), 10(6), and 10(7) CFU/mL) and L. monocytogenes strain (10 strains). The growth of L. monocytogenes Scott A in MWB at 7 °C, 10 °C and 14 °C was consistently bi-phasic and independent of growth rate; at 18 °C, growth was consistently mono-phasic (single-phase, typical sigmoid growth curves), whereas no growth was observed at 4 °C. The tested modifications in the composition of MWB did not influence the bi-phasic nature of L. monocytogenes Scott A growth at 7 °C, and, overall, we could not point out any strain-, or serotype-specific effects. On the other hand, the initial inoculum level appears to affect the form of the growth curve, as there was a shift towards mono-phasic growth in trials with increasing initial inocula. A mathematical model, based on a stepwise response and described through two sequential sigmoid curves, was used to describe bi-phasic growth and estimate the kinetic parameters of L. monocytogenes growth. An alternative hypothesis, based on the assumption of the existence of two subpopulations, possessing different growth kinetics, materialized under the stress imposed on L. monocytogenes cells due to the

  7. Biphasic and boundary lubrication mechanisms in artificial hydrogel cartilage: A review.

    PubMed

    Murakami, Teruo; Yarimitsu, Seido; Nakashima, Kazuhiro; Sakai, Nobuo; Yamaguchi, Tetsuo; Sawae, Yoshinori; Suzuki, Atsushi

    2015-12-01

    Various studies on the application of artificial hydrogel cartilage to cartilage substitutes and artificial joints have been conducted. It is expected in clinical application of artificial hydrogel cartilage that not only soft-elastohydrodynamic lubrication but biphasic, hydration, gel-film and boundary lubrication mechanisms will be effective to sustain extremely low friction and minimal wear in daily activities similar to healthy natural synovial joints with adaptive multimode lubrication. In this review article, the effectiveness of biphasic lubrication and boundary lubrication in hydrogels in thin film condition is focused in relation to the structures and properties of hydrogels. As examples, the tribological behaviors in three kinds of poly(vinyl alcohol) hydrogels with high water content are compared, and the importance of lubrication mechanism in biomimetic artificial hydrogel cartilage is discussed to extend the durability of cartilage substitute.

  8. Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development

    SciTech Connect

    Cheng, Xin; Chen, Jian-long; Ma, Zheng-lai; Zhang, Zhao-long; Lv, Shun; Mai, Dong-mei; Liu, Jia-jia; Chuai, Manli; Lee, Kenneth Ka Ho; Wan, Chao; Yang, Xuesong

    2014-11-15

    increased in mesenchymal cell mass treated by low concentration of Dex. Mmp-13 expression was obviously up-regulated by Dex in both mesenchymal cells and primary chondrocyte cultures. And Col10a1 expression was also increased by Dex exposure in chondrocyte. In summary, we have revealed that different concentrations of Dex exposure during early gestation could exert a biphasic effect on vertebrate skeletal development. - Highlights: • Chick embryos occurred shortening of the long bone following Dex exposure. • Dex suppressed chondrocytes proliferation and promoted apoptosis. • Dex exposure decreased ALP production and up-regulated Runx-2 and Mmp-13. • Dex exhibited biphasic effects on chondrogenic proliferation and nodule formation. • The hypertrophy and ossification were accelerated by Dex both in vivo and in vitro.

  9. Differential effects of carbamazepine on negatively versus positively reinforced responding.

    PubMed

    Caruso, Mary; Harvey, Mark T; Roberts, Celeste; Patterson, Tina G; Kennedy, Craig H

    2002-12-01

    To assess its effects on negatively versus positively reinforced operant behavior, carbamazepine (CBZ) or vehicle was acutely administered to rats. Negative reinforcement baselines consisted of a free-operant avoidance task with 5-s shock-shock and 20-s response-shock intervals. Positive reinforcement baselines consisted of responding for food pellets on a variable interval 30-s schedule. Ascending dose-effect functions were established using CBZ for negatively reinforced responding (vehicle, 25, 50, 100 mg/kg ip) and positively reinforced responding (vehicle, 12.5, 25, 50, 100 mg/kg ip). Negatively reinforced responses and avoided shocks were significantly reduced by CBZ injections at 100 mg/kg. Positively reinforced responses and food pellet deliveries were significantly reduced by CBZ injections at 25, 50, and 100 mg/kg. The results show that CBZ has differential, dose-dependent effects on negatively versus positively reinforced responding.

  10. Positivity Effect Specific to Older Adults with Subclinical Memory Impairment

    ERIC Educational Resources Information Center

    Leal, Stephanie L.; Noche, Jessica A.; Murray, Elizabeth A.; Yassa, Michael A.

    2016-01-01

    Numerous studies have suggested that older adults preferentially remember positive information ("positivity effect"), however others have reported mixed results. One potential source of conflict is that aging is not a unitary phenomenon and individual differences exist. We modified a standard neuropsychological test to vary emotional…

  11. Biphasic regulation of lysosomal exocytosis by oxidative stress.

    PubMed

    Ravi, Sreeram; Peña, Karina A; Chu, Charleen T; Kiselyov, Kirill

    2016-11-01

    Oxidative stress drives cell death in a number of diseases including ischemic stroke and neurodegenerative diseases. A better understanding of how cells recover from oxidative stress is likely to lead to better treatments for stroke and other diseases. The recent evidence obtained in several models ties the process of lysosomal exocytosis to the clearance of protein aggregates and toxic metals. The mechanisms that regulate lysosomal exocytosis, under normal or pathological conditions, are only beginning to emerge. Here we provide evidence for the biphasic effect of oxidative stress on lysosomal exocytosis. Lysosomal exocytosis was measured using the extracellular levels of the lysosomal enzyme beta-hexosaminidase (ß-hex). Low levels or oxidative stress stimulated lysosomal exocytosis, but inhibited it at high levels. Deletion of the lysosomal ion channel TRPML1 eliminated the stimulatory effect of low levels of oxidative stress. The inhibitory effects of oxidative stress appear to target the component of lysosomal exocytosis that is driven by extracellular Ca(2+). We propose that while moderate oxidative stress promotes cellular repair by stimulating lysosomal exocytosis, at high levels oxidative stress has a dual pathological effect: it directly causes cell damage and impairs damage repair by inhibiting lysosomal exocytosis. Harnessing these adaptive mechanisms may point to pharmacological interventions for diseases involving oxidative proteotoxicity or metal toxicity.

  12. Elimination of the biphasic pharmacodynamics of 15d-PGJ2 by controlling its release from a nanoemulsion

    PubMed Central

    Abbasi, Saed; Kajimoto, Kazuaki; Harashima, Hideyoshi

    2016-01-01

    15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) has a dual action of stimulating anti-inflammation and anti-proliferation when exogenously administered at high doses. However, at lower doses, it can be toxic inducing opposite actions, ie, stimulation of both inflammation and cell proliferation. This biphasic phenomenon of 15d-PGJ2 is believed to be due to its multitarget behavior. In this study, we provide a strategy for controlling such biphasic pharmacodynamics by separating its dual actions while retaining the beneficial one by using a nanoemulsion (NE). The 15d-PGJ2 was encapsulated in the NE composed of triolein/distearoyl phosphatidylcholine/Tween 80 at a high encapsulation ratio (>83%). Furthermore, NE enhanced drug retention by slowing down its release rate, which was, unconventionally, inversely dependent on the total surface area of the NE system. Next, focusing on the biphasic effect on cell proliferation, we found that the 15d-PGJ2-loaded slow-release NE showed only a dose-dependent inhibition of the viability of a mouse macrophage cell line, RAW264.7, although a fast-release NE as well as free 15d-PGJ2 exerted a biphasic effect. The observed slow-release kinetics are believed to be responsible for elimination of the biphasic pharmacodynamics of 15d-PGJ2 mainly for two reasons: 1) a high proportion of 15d-PGJ2 that is retained in the NE was delivered to the cytosol, where proapoptotic targets are located and 2) 15d-PGJ2 was able to bypass cell membrane-associated targets that lead to the induction of cellular proliferation. Collectively, our strategy of eliminating the 15d-PGJ2-induced biphasic pharmacodynamics was based on the delivery of 15d-PGJ2 to its desired site of action, excluding undesired sites, on a subcellular level. PMID:27354798

  13. Biphasic modulation of cell growth by recombinant human galectin-1.

    PubMed

    Adams, L; Scott, G K; Weinberg, C S

    1996-06-13

    Human soluble galactose-binding lectin (galectin-1) has been expressed as an Escherichia coli fusion protein, following the amplification by polymerase chain reaction of cDNA prepared from a human osteosarcoma cell line. The fusion protein is a functional beta-galactoside-binding lectin, as is the recombinant galectin when purified from the cleaved fusion protein. The recombinant galectin has a biphasic effect on cell proliferation. Unlike the fusion protein, it functions as a human cell growth inhibitor, confirming earlier findings with natural human galectin-1, though it is less effective than the natural galectin. This reaction is not significantly inhibited by lactose, and is thus largely independent of the beta-galactoside-binding site. At lower concentrations, recombinant galectin-1 is mitogenic, this activity being susceptible to inhibition by lactose, and thus attributable to the beta-galactoside-binding ability of the protein. Some tumour cells are susceptible to the growth-inhibitory effect, and the galectin-1 gene is expressed in both normal and tumour cells.

  14. Microstructure Evolution of Biphasic TiNi1+ x Sn Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Verma, Nisha; Douglas, Jason E.; Krämer, Stephan; Pollock, Tresa M.; Seshadri, Ram; Levi, Carlos G.

    2016-08-01

    The effects of thermal treatment on the microstructure of biphasic materials comprising half-Heusler (hH) and full-Heusler (fH) phases, as well as on their associated thermal conductivity, are discussed. The focus of this study was on a biphasic hH/fH alloy of nominal stoichiometry TiNi1.2Sn, synthesized by containerless (magnetic levitation) induction melting. The alloy samples were exposed to various heat treatments to generate microstructures containing second-phase precipitates ranging in size from ~10 nm to a few micrometers. The materials were characterized with regard to morphology, size, shape, and orientation relationship of the fH and hH phases, both of which were present as precipitates within larger regions of the counterpart phase. The solidification path of the alloy and its implications for the subsequent microstructure evolution during heat treatment were elucidated, and relationships with the ensuing thermal conductivity were characterized.

  15. A biphasic mercury-ion sensor: exploiting microfluidics to make simple anilines competitive ligands.

    PubMed

    Petzoldt, Martin; Eschenbaum, Carsten; Schwaebel, S Thimon; Broedner, Kerstin; Lemmer, Uli; Hamburger, Manuel; Bunz, Uwe H F

    2015-10-05

    Combining the molecular wire effect with a biphasic sensing approach (analyte in water, sensor-dye in 2-methyltetrahydrofuran) and a microfluidic flow setup leads to the construction of a mercury-sensitive module. We so instantaneously detect Hg(2+) ions in water at a 500 μM concentration. The sensor, conjugated non-water soluble polymer 1 (XFPF), merely supports dibutylaniline substituents as binding units. Yet, selective and sensitive detection of Hg(2+) -ions is achieved in water. The enhancement in sensory response, when comparing the reference compound 2 to that of 1 in a biphasic system in a microfluidic chip is >10(3) . By manipulation of the structure of 1, further powerful sensor systems should be easily achieved.

  16. Vertebral position alters paraspinal muscle spindle responsiveness in the feline spine: effect of positioning duration.

    PubMed

    Ge, Weiqing; Long, Cynthia R; Pickar, Joel G

    2005-12-01

    Proprioceptive information from paraspinal tissues including muscle contributes to neuromuscular control of the vertebral column. We investigated whether the history of a vertebra's position can affect signalling from paraspinal muscle spindles. Single unit recordings were obtained from muscle spindle afferents in the L6 dorsal roots of 30 Nembutal-anaesthetized cats. Each afferent's receptive field was in the intact muscles of the low back. The L6 vertebra was controlled using a displacement-controlled feedback motor and was held in each of three different conditioning positions for durations of 0, 2, 4, 6 and 8 s. Conditioning positions (1.0-2.2 mm dorsal and ventral relative to an intermediate position) were based upon the displacement that loaded the L6 vertebra to 50-60% of the cat's body weight. Following conditioning positions that stretched (hold-long) and shortened (hold-short) the spindle, the vertebra was repositioned identically and muscle spindle discharge at rest and to movement was compared with conditioning at the intermediate position. Hold-short conditioning augmented mean resting spindle discharge by +4.1 to +6.2 impulses s(-1); however, the duration of hold-short did not significantly affect this increase (F(4,145) = 0.49, P = 0.74). The increase was maintained at the beginning of vertebral movement but quickly returned to baseline. Conversely, hold-long conditioning significantly diminished mean resting spindle discharge by -2.0 to -16.1 impulses s(-1) (F(4,145) = 11.23, P < 0.001). The relationship between conditioning duration and the diminished resting discharge could be described by a quadratic (F(1,145) = 9.28, P = 0.003) revealing that the effects of positioning history were fully developed within 2 s of conditioning. In addition, 2 s or greater of hold-long conditioning significantly diminished spindle discharge to vertebral movement by -5.7 to -10.0 impulses s(-1) (F(4,145) = 11.0, P < 0.001). These effects of vertebral positioning

  17. A Phenomenological Model of the Electrically Stimulated Auditory Nerve Fiber: Temporal and Biphasic Response Properties

    PubMed Central

    Horne, Colin D. F.; Sumner, Christian J.; Seeber, Bernhard U.

    2016-01-01

    We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs). The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability) under both monophasic and cathodic-anodic biphasic stimulation, without changing the model's parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG) of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions. Our work extends the stochastic leaky integrate and fire (SLIF) neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model. PMID:26903850

  18. Contextual effect of positive intergroup contact on outgroup prejudice.

    PubMed

    Christ, Oliver; Schmid, Katharina; Lolliot, Simon; Swart, Hermann; Stolle, Dietlind; Tausch, Nicole; Al Ramiah, Ananthi; Wagner, Ulrich; Vertovec, Steven; Hewstone, Miles

    2014-03-18

    We assessed evidence for a contextual effect of positive intergroup contact, whereby the effect of intergroup contact between social contexts (the between-level effect) on outgroup prejudice is greater than the effect of individual-level contact within contexts (the within-level effect). Across seven large-scale surveys (five cross-sectional and two longitudinal), using multilevel analyses, we found a reliable contextual effect. This effect was found in multiple countries, operationalizing context at multiple levels (regions, districts, and neighborhoods), and with and without controlling for a range of demographic and context variables. In four studies (three cross-sectional and one longitudinal) we showed that the association between context-level contact and prejudice was largely mediated by more tolerant norms. In social contexts where positive contact with outgroups was more commonplace, norms supported such positive interactions between members of different groups. Thus, positive contact reduces prejudice on a macrolevel, whereby people are influenced by the behavior of others in their social context, not merely on a microscale, via individuals' direct experience of positive contact with outgroup members. These findings reinforce the view that contact has a significant role to play in prejudice reduction, and has great policy potential as a means to improve intergroup relations, because it can simultaneously impact large numbers of people.

  19. Contextual effect of positive intergroup contact on outgroup prejudice

    PubMed Central

    Christ, Oliver; Schmid, Katharina; Lolliot, Simon; Swart, Hermann; Stolle, Dietlind; Tausch, Nicole; Al Ramiah, Ananthi; Wagner, Ulrich; Vertovec, Steven; Hewstone, Miles

    2014-01-01

    We assessed evidence for a contextual effect of positive intergroup contact, whereby the effect of intergroup contact between social contexts (the between-level effect) on outgroup prejudice is greater than the effect of individual-level contact within contexts (the within-level effect). Across seven large-scale surveys (five cross-sectional and two longitudinal), using multilevel analyses, we found a reliable contextual effect. This effect was found in multiple countries, operationalizing context at multiple levels (regions, districts, and neighborhoods), and with and without controlling for a range of demographic and context variables. In four studies (three cross-sectional and one longitudinal) we showed that the association between context-level contact and prejudice was largely mediated by more tolerant norms. In social contexts where positive contact with outgroups was more commonplace, norms supported such positive interactions between members of different groups. Thus, positive contact reduces prejudice on a macrolevel, whereby people are influenced by the behavior of others in their social context, not merely on a microscale, via individuals’ direct experience of positive contact with outgroup members. These findings reinforce the view that contact has a significant role to play in prejudice reduction, and has great policy potential as a means to improve intergroup relations, because it can simultaneously impact large numbers of people. PMID:24591627

  20. A comparison of lipase-catalyzed ester hydrolysis in reverse micelles, organic solvents, and biphase systems

    SciTech Connect

    Yang, F.; Russell, A.J.

    1995-07-05

    The performance of lipases from Candida rugosa and wheat germ have been investigated in three reaction media using three acetate hydrolyses as model reactions (ethyl acetate, allyl acetate, and prenyl acetate). The effect of substrate properties and water content were studied for each system (organic solvent, biphasic system, and reverse micelles). Not unexpectedly, the effect of water content is distinct for each system, and the optimal water content for enzyme activity is not always the same as that for productivity. A theoretical model has been used to simulate and predict enzyme performance in reverse micelles, and a proposed partitioning model for biphasic systems agrees well with experimental results. While the highest activities observed were in the micellar system, productivity in microemulsions is limited by low enzyme concentrations. Biphasic systems, however, support relatively good activity and productivity. The addition of water to dry organic solvents, combined with the dispersion of lyophilized enzyme powders in the solvent, resulted in significant enzyme aggregation, which not surprisingly limits the applicability of the ``anhydrous`` enzyme suspension approach.

  1. Effects of the Positive Action Program on Indicators of Positive Youth Development Among Urban Youth.

    PubMed

    Lewis, Kendra M; Vuchinich, Samuel; Ji, Peter; DuBois, David L; Acock, Alan; Bavarian, Niloofar; Day, Joseph; Silverthorn, Naida; Flay, Brian R

    This study evaluated effects of Positive Action, a school-based social-emotional and character development (SECD) intervention, on indicators of positive youth development (PYD) among a sample of low-income, ethnic minority youth attending 14 urban schools. The study used a matched-pair, cluster-randomized controlled design at the school level. A multiple-measure self-report protocol assessed four key strengths and resources for PYD: self-concept, peer affiliations, ethics, and social skills. Students (n=1170) were assessed from grades 3 to 8, the duration of the intervention, with drop-outs and late entrants included in analyses. Growth curve analyses revealed evidence of favorable program effects on each of the four types of resources. The study contributes to PYD research by providing evidence for school-based interventions in low-income, urban contexts for ethnic minority youth.

  2. Effects of the Positive Action Program on Indicators of Positive Youth Development Among Urban Youth

    PubMed Central

    Lewis, Kendra M.; Vuchinich, Samuel; Ji, Peter; DuBois, David L.; Acock, Alan; Bavarian, Niloofar; Day, Joseph; Silverthorn, Naida; Flay, Brian R.

    2015-01-01

    This study evaluated effects of Positive Action, a school-based social-emotional and character development (SECD) intervention, on indicators of positive youth development (PYD) among a sample of low-income, ethnic minority youth attending 14 urban schools. The study used a matched-pair, cluster-randomized controlled design at the school level. A multiple-measure self-report protocol assessed four key strengths and resources for PYD: self-concept, peer affiliations, ethics, and social skills. Students (n=1170) were assessed from grades 3 to 8, the duration of the intervention, with drop-outs and late entrants included in analyses. Growth curve analyses revealed evidence of favorable program effects on each of the four types of resources. The study contributes to PYD research by providing evidence for school-based interventions in low-income, urban contexts for ethnic minority youth. PMID:26941548

  3. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    SciTech Connect

    K. Osseo-Asare; X. Zeng

    2001-06-30

    Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behaviors of silica in the polyethylene glycol (PEG)/dextran (Dex) and dextran/Triton X-100 (TX100) systems have been investigated, and the effects of sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) on solid partition have been studied. In both biphase systems, silica particles stayed in the top PEG-rich phase at low pH. With increase in pH, the particles moved from the top phase to the interface, then to the bottom phase. At very high pH, the solids preferred the top phase again. These trends are attributable to variations in the polymer/solid and nonionic surfactant/solid interactions. Addition of ionic surfactants into these two systems introduces a weakly charged environment, since ionic surfactants concentrate into one phase, either the top phase or the bottom phase. Therefore, coulombic forces also play a key role in the partition of silica particles because electrostatic attractive or repulsive forces are produced between the solid surface and the ionic-surfactant-concentrated phase. For the PEG/dextran system in the presence of SDS, SiO{sub 2} preferred the bottom dextran-rich phase above its pH{sub PZC}. However, addition of DTAB moved the oxide particles from the top phase to the interface, and then to the bottom phase, with increase in pH. These different behaviors are attributable to the fact that SDS and DTAB concentrated into the opposite phase of the PEG/dextran system. On the other hand, in the dextran/Triton X-100 system, both ionic surfactants concentrated in the top surfactant-rich phase and formed mixed micelles with TX100. Therefore, addition of the anionic surfactant, SDS, moved the silica particles from top phase to the

  4. Assessment of balanced biphasic defibrillation waveforms in transthoracic atrial cardioversion.

    PubMed

    Krasteva, V; Trendafilova, E; Cansell, A; Daskalov, I

    2001-01-01

    Various electrical pulses have been used for defibrillation. The monophasic damped sinusoid waveform, initiated in 60 s, was adopted in virtually all defibrillators. Biphasic pulses were introduced recently, achieving success with less energy. A biphasic exponential waveform was modelled with 4 ms duration per phase with a balanced 3:1 ratio of the first to second phase peak voltages and implemented in a defibrillator. A version obtained by chopping the pulses with a 5 kHz frequency was also used. It was hypothesized that the modelled transmembrane voltage decay time is a parameter that could be associated with successful defibrillation. The results of cardioversion for two groups of patients with the 'classic' monophasic waveform and with the biphasic pulses were compared. The mean efficient energy with the damped sinusoid was 205 +/- 85 J, versus 88 +/- 43 J with the biphasic pulses, yielding a ratio of 2.32 (1.92 to 3.2 for fibrillation and flutter, respectively). An acceptable agreement between model data and clinical results was found. The transmembrane voltage decay time ratios for monophasic versus biphasic pulses was in the approximate range of 2.5 to 3.5.

  5. Biphasic catalysis in water/carbon dioxide micellar systems

    DOEpatents

    Jacobson, Gunilla B.; Tumas, William; Johnston, Keith P.

    2002-01-01

    A process is provided for catalyzing an organic reaction to form a reaction product by placing reactants and a catalyst for the organic reaction, the catalyst of a metal complex and at least one ligand soluble within one of the phases of said aqueous biphasic system, within an aqueous biphasic system including a water phase, a dense phase fluid, and a surfactant adapted for forming an emulsion or microemulsion within the aqueous biphasic system, the reactants soluble within one of the phases of the aqueous biphasic system and convertible in the presence of the catalyst to a product having low solubility in the phase in which the catalyst is soluble; and, maintaining the aqueous biphasic system under pressures, at temperatures, and for a period of time sufficient for the organic reaction to occur and form the reaction product and to maintain sufficient density on the dense phase fluid, the reaction product characterized as having low solubility in the phase in which the catalyst is soluble.

  6. The effect of selective availability on differential GPS positioning

    NASA Astrophysics Data System (ADS)

    Tolman, Brian W.; Coco, David S.; Leach, Mark P.; Clynch, James R.

    The effect of Selective Availability (SA) on differential positioning is considered, using an extensive two-frequency P code data set which was collected during two periods: a publicly announced test of the GPS constellation in October, 1989, and after it was announced that SA had been implemented, in April 1990. The data were collected with the cooperation of several organizations, using TI 4100 receivers and atomic clocks at 6 sites, spanning baselines from 8 to 1350 kilometers, over a total of more than 25 days. A subset of this data set shows strong characteristics which are probably due to SA. Differential positions which have been computed using this 'unhealthy' data are compared to truth positions, and to identically computed positions using apparently 'healthy' data from the same period. The results and their implications for the impact that SA could have on differential positioning are presented.

  7. Biphasic nanoparticles made by electrified jetting

    NASA Astrophysics Data System (ADS)

    Lahann, Joerg

    2005-03-01

    Nano-colloids have recently attracted intense attention due to unique properties that are distinctly different from bulk solid-state materials; including unique magnetic, electronic, optical, chemical, and biological characteristics. The vision that these nano-objects could essentially act as functional components in novel device generations, which ``magically'' assemble following a master blueprint void any human manipulation, has resulted in a new ``gold rush'' in materials science. These concepts have results in the synthesis of a multitude of nano-objects, such as nano-wires, nano-rods, nano-disks, or nano-prisms.^ Recently, nano-particles with anisotropic materials distributions (biphasic nano-particles) moved in the focus of research. Our approach differs fundamentally from the above-mentioned methods in that it takes advantage of electrified polymer jets to create anisotropic materials distributions in nano-objects. jetting is a process to generate liquid jets by use of electrostatic forces. It is well-known that high electrical potentials (typically several thousand volts) applied between the jetting liquids that are fed through a capillary and a collecting substrate will induce jetting of a charged liquid. The differences in the final morphologies from similar processes are mainly determined by the properties of the jetting liquids and the process parameters. transmission electron microscopy, scanning electron microscopy, and scanning laser confocal microscopy, we demonstrate the applicability of the process to control size, shape, and materials distribution at the nanoscale. The resulting anisotropic nanoparticles may have potential applications for targeted drug delivery or as electro-rehological fluids. a) F. M. Van der Kooij, K. Kassapidou and H. N. W. Lekkerkerker, Liquid crystal phase transitions in suspensions of polydisperse plate-like particles, Nature 406, 868 (2000); b) C. A. Mirkin, R. L. Letsinger, R. C. Mucic and J. J. Storhoff, A DNA

  8. Time perspective and positivity effects in Alzheimer's disease.

    PubMed

    Bohn, Linzy; Kwong See, Sheree T; Fung, Helene H

    2016-09-01

    This study tested whether time perspective, a central tenant of socioemotional selectivity theory (Carstensen, 2006), moderates positivity effects in emotional memory. To provide measures of time perspective, young (YA; M = 22.48 years), young-old (YO; M = 67.56 years), old-old adults (OO; M = 80.24 years), and participants with moderate severity Alzheimer's disease (PAD; M = 84.28 years) completed a line task and reported subjective age. As expected, YA, YO, and OO reported successively more constrained future time perspectives. PAD showed distortion in time perspective, envisioning a future comparable with the YO, although closer matched in chronological age to OO adults. To evince positivity effects, participants were oriented to pairs of emotional images and were then tested for memory (recall and recognition) of the images. Recall and recognition memory for the images indicated an age-related advantage for positive over negative material (positivity effects). Time perspective, however, did not moderate these age effects. In memory performance, PAD were more comparable with OO adults with whom they shared a similar chronological age, rather than YO adults, who had a corresponding time perspective. These results suggest that age correlates that are shared by PAD and OO, such as reduced processing resources, rather than time perspective, may drive the age associated positivity effects. (PsycINFO Database Record

  9. INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)

    EPA Science Inventory

    In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

  10. Comparison between FEBio and Abaqus for biphasic contact problems

    PubMed Central

    Jin, Zhongmin; Fisher, John; Wilcox, Ruth

    2013-01-01

    Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of this study was to undertake a direct comparison between FEBio and Abaqus for some practical contact problems involving cartilage. Three model types, representing a porous flat-ended indentation test, a spherical-ended indentation test, and a conceptual natural joint contact model, were compared. In addition, a parameter sensitivity study was also performed for the spherical-ended indentation test to investigate the effects of changes in the input material properties on the model outputs, using both FEBio and Abaqus. Excellent agreement was found between FEBio and Abaqus for all of the model types and across the range of material properties that were investigated. PMID:23804955

  11. Biphasic Oxidation of Oxy-Hemoglobin in Bloodstains

    PubMed Central

    Bremmer, Rolf H.; de Bruin, Daniel M.; de Joode, Maarten; Buma, Wybren Jan; van Leeuwen, Ton G.; Aalders, Maurice C. G.

    2011-01-01

    Background In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO2) to met-hemoglobin (met-Hb) and hemichrome (HC). The fractions of HbO2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. Methodology The fractions of HbO2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450–800 nm), were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. Conclusions The oxidation rate of HbO2 in bloodstains is biphasic. At first, the oxidation of HbO2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene. PMID:21789186

  12. Comparison between FEBio and Abaqus for biphasic contact problems.

    PubMed

    Meng, Qingen; Jin, Zhongmin; Fisher, John; Wilcox, Ruth

    2013-09-01

    Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of this study was to undertake a direct comparison between FEBio and Abaqus for some practical contact problems involving cartilage. Three model types, representing a porous flat-ended indentation test, a spherical-ended indentation test, and a conceptual natural joint contact model, were compared. In addition, a parameter sensitivity study was also performed for the spherical-ended indentation test to investigate the effects of changes in the input material properties on the model outputs, using both FEBio and Abaqus. Excellent agreement was found between FEBio and Abaqus for all of the model types and across the range of material properties that were investigated.

  13. Position-dependent effects of polylysine on Sec protein transport.

    PubMed

    Liang, Fu-Cheng; Bageshwar, Umesh K; Musser, Siegfried M

    2012-04-13

    The bacterial Sec protein translocation system catalyzes the transport of unfolded precursor proteins across the cytoplasmic membrane. Using a recently developed real time fluorescence-based transport assay, the effects of the number and distribution of positive charges on the transport time and transport efficiency of proOmpA were examined. As expected, an increase in the number of lysine residues generally increased transport time and decreased transport efficiency. However, the observed effects were highly dependent on the polylysine position in the mature domain. In addition, a string of consecutive positive charges generally had a more significant effect on transport time and efficiency than separating the charges into two or more charged segments. Thirty positive charges distributed throughout the mature domain resulted in effects similar to 10 consecutive charges near the N terminus of the mature domain. These data support a model in which the local effects of positive charge on the translocation kinetics dominate over total thermodynamic constraints. The rapid translocation kinetics of some highly charged proOmpA mutants suggest that the charge is partially shielded from the electric field gradient during transport, possibly by the co-migration of counter ions. The transport times of precursors with multiple positively charged sequences, or "pause sites," were fairly well predicted by a local effect model. However, the kinetic profile predicted by this local effect model was not observed. Instead, the transport kinetics observed for precursors with multiple polylysine segments support a model in which translocation through the SecYEG pore is not the rate-limiting step of transport.

  14. Biphasic materials for bone grafting and hyperthermia treatment of cancer.

    PubMed

    Arcos, D; del Real, R P; Vallet-Regí, M

    2003-04-01

    Three biphasic materials have been synthesized from a magnetic glass-ceramic (Si-Ca-Fe) and a bioactive sol-gel glass (Si-P-Ca). The ratios of glass-ceramic:sol-gel glass used in this work were 1:1, 2:1, and 5:1. These materials show bioactive and magnetic properties and can be used as thermoseeds for hyperthermia treatment of bone tumors. The sol-gel glass content affects the textural properties of the glass-ceramic, giving rise to porosity, which plays a fundamental role in the formation of an apatite-like layer on the surface. On the other hand, as the sol-gel glass content increases, the magnetic properties change due to the diffusion of Fe ions to the glassy phases of the biphasic materials. The biphasic nature of these materials allows the changing of both properties, depending on the requirements of the patient.

  15. Progress on the biphase turbine at Cerro Prieto

    SciTech Connect

    Cerini, D.; Hays, L.; Studhalter, W.

    1997-12-31

    The status of a Biphase turbine power plant being installed at the Cerro Prieto geothermal field is presented. The major modules for the power plant are completed except for a back pressure steam turbine. The power plant will be started in April 1997 with the Biphase turbine alone followed by the addition of the steam turbine module two months later. The current power plant performance level is 2780 kWe due to a decline in the well. An increase in power output to 4060 kWe by adding the flow from another well is planned. The addition of five Biphase power plants with a total power output of 21.2 megawatts is described.

  16. Microfluidic electrospinning of biphasic nanofibers with Janus morphology

    PubMed Central

    Srivastava, Yasmin; Marquez, Manuel; Thorsen, Todd

    2009-01-01

    In this paper a method of electrospinning conducting and nonconducting biphasic Janus nanofibers using microfluidic polydimethylsiloxane (PDMS)-based manifolds is described. Key benefits of using microfluidic devices for nanofiber synthesis include rapid prototyping, ease of fabrication, and the ability to spin multiple Janus fibers in parallel through arrays of individual microchannels. Biphasic Janus nanofibers of polyvinylpyrrolidone (PVP)+polypyrrole (PPy)∕PVP nanofibers with an average diameter of 250 nm were successfully fabricated using elastomeric microfluidic devices. Fiber characterization and confirmation of the Janus morphology was subsequently carried out using a combination of scanning electron microscopy, energy dispersion spectroscopy, and transmission electron microscopy. PMID:19693390

  17. Case Report: Multifocal biphasic squamoid alveolar renal cell carcinoma

    PubMed Central

    Lopez, Jose Ignacio

    2016-01-01

    A multifocal biphasic squamoid alveolar renal cell carcinoma in a 68-year-old man is reported. Four different peripheral tumor nodules were identified on gross examination. A fifth central tumor corresponded to a conventional clear cell renal cell carcinoma. Biphasic squamoid alveolar renal cell carcinoma is a rare tumor that has been very recently characterized as a distinct histotype within the spectrum of papillary renal cell carcinoma. Immunostaining with cyclin D1 seems to be specific of this tumor subtype. This is the first reported case with multifocal presentation. PMID:27158455

  18. The effect of illuminant position on perceived curvature.

    PubMed

    Curran, W; Johnston, A

    1996-05-01

    In shaded scenes surface features can appear either concave or convex, depending upon the viewer's judgement about the direction of the prevailing illumination. If other curvature cues are added to the image this ambiguity can be removed. However, it is not clear to what extent, if any, illuminant position exerts an influence on the perceived magnitude of surface curvature. Subjects were presented with pairs of spherical surface patches in a curvature matching task. The patches were defined by shading and texture cues. The perceived curvature of a standard patch was measured as a function of light source position. We found a clear effect of light source position on apparent curvature. Perceived curvature decreased as light source tilt increased and as light source slant decreased. We also found that the strength of this effect is determined partly by a surface's reflectance function and partly by the relative weight of the texture cue. When a specular component was added to the stimuli, the effect of light source orientation was weakened. The weight of the texture cue was manipulated by disrupting the regular distribution of texture elements. We found an inverse relationship between the strength of the effect and the weight of the texture cue: lowering the texture cue weight resulted in an enhancement of the illuminant position effect.

  19. Histone Gene Multiplicity and Position Effect Variegation in DROSOPHILA MELANOGASTER

    PubMed Central

    Moore, Gerald D.; Sinclair, Donald A.; Grigliatti, Thomas A.

    1983-01-01

    The histone genes of wild-type Drosophila melanogaster are reiterated 100–150 times per haploid genome and are located in the segment of chromosome 2 that corresponds to polytene bands 39D2-3 to E1-2. The influence of altered histone gene multiplicity on chromatin structure has been assayed by measuring modification of the gene inactivation associated with position effect variegation in genotypes bearing deletions of the 39D-E segment. The proportion of cells in which a variegating gene is active is increased in genotypes that are heterozygous for a deficiency that removes the histone gene complex. Deletions that remove segments adjacent to the histone gene complex have no effect on the expression of variegating genes. Suppression of position effect variegation associated with reduction of histone gene multiplicity applies to both X-linked and autosomal variegating genes. Position effects exerted by both autosomal and sex-chromosome heterochromatin were suppressible by deletions of the histone gene complex. The suppression was independent of the presence of the Y chromosome. A deficiency that deletes only the distal portion of the histone gene complex also has the ability to suppress position effect variegation. Duplication of the histone gene complex did not enhance position effect variegation. Deletion or duplication of the histone gene complex in the maternal genome had no effect on the extent of variegation in progeny whose histone gene multiplicity was normal. These results are discussed with respect to current knowledge of the organization of the histone gene complex and control of its expression. PMID:17246163

  20. Panax ginseng and Eleutherococcus senticosus may exaggerate an already existing biphasic response to stress via inhibition of enzymes which limit the binding of stress hormones to their receptors.

    PubMed

    Gaffney, B T; Hügel, H M; Rich, P A

    2001-05-01

    A mechanism of action for Panax ginseng (PG) and Eleutherococcus senticosus (ES) is proposed which explains how they could produce the paradoxical effect of sometimes increasing and sometimes decreasing the stress response. The mechanism suggests that this biphasic effect results from increased occupancy of positive and negative feedback stress hormone receptors by their natural ligands due to inhibition of specific enzymes which function to limit receptor occupancy. Specifically, it is suggested that PG inhibits 11-beta hydroxysteroid dehydrogenase one and ES inhibits catechol- O -methyl transferase, both of which reside in close proximity to stress hormone receptors and catalyse the degradation of stress hormones into inactive compounds. In addition, it is suggested that the increased energy said to result from PG and ES may be a consequence of their increasing the occupancy of stress hormone receptors which function to redistribute the body's energy reserves from regeneration to activity.

  1. The Effectiveness of CASAs in Achieving Positive Outcomes for Children.

    ERIC Educational Resources Information Center

    Litzelfelner, Pat

    2000-01-01

    Evaluated effectiveness of court-appointed special advocates (CASAs) in achieving positive outcomes for children in the child welfare system, using data from court and CASA program files on 200 children. Found that CASAs may have reduced the number of placements and court continuances children experienced. More services were provided to children…

  2. Long-Term Effects of the Positive Action Program.

    ERIC Educational Resources Information Center

    Flay, Brian R.; Allred, Carol G.

    2003-01-01

    Used a matched-schools design, school-level achievement, and disciplinary data to evaluate the effectiveness of the elementary-level Positive Action program on students' performance and behavior over time. Results indicated that program participation improved student behavior, school involvement, and academic achievement into high school. The…

  3. The Positive Effects of Cognitive Learning Styles in ELT Classes

    ERIC Educational Resources Information Center

    Yagcioglu, Ozlem

    2016-01-01

    In the EFL, ESL, ESP and in the ELT classes, students are taught their courses with different kinds of methods and approaches. Cognitive learning styles are the most essential styles in foreign language education. In this paper, the positive effects of cognitive learning styles will be handled. The benefits of these styles will be highlighted.…

  4. The Theory Behind the Age-Related Positivity Effect

    PubMed Central

    Reed, Andrew E.; Carstensen, Laura L.

    2012-01-01

    The “positivity effect” refers to an age-related trend that favors positive over negative stimuli in cognitive processing. Relative to their younger counterparts, older people attend to and remember more positive than negative information. Since the effect was initially identified and the conceptual basis articulated (Mather and Carstensen, 2005) scores of independent replications and related findings have appeared in the literature. Over the same period, a number of investigations have failed to observe age differences in the cognitive processing of emotional material. When findings are considered in theoretical context, a reliable pattern of evidence emerges that helps to refine conceptual tenets. In this article we articulate the operational definition and theoretical foundations of the positivity effect and review the empirical evidence based on studies of visual attention, memory, decision making, and neural activation. We conclude with a discussion of future research directions with emphasis on the conditions where a focus on positive information may benefit and/or impair cognitive performance in older people. PMID:23060825

  5. Verapamil exerts biphasic modulation on phenobarbital transport across the blood-brain barrier: evidence from an in vivo and in vitro study.

    PubMed

    Yao, Dan; Yang, Zhi-Hong; Liu, Li; Li, Jia; Yu, Yun-Li; Zhang, Lu-Lu; Pan, Xian; Liu, Xiao-Dong; Xie, Lin; Wang, Guang-Ji

    2011-04-01

    The aim of the study was to report a concentration-dependently biphasic effect of verapamil (VER) on the transport of phenobarbital (PB) across the blood-brain barrier (BBB) in vitro and in vivo. The uptake of PB by rat brain microvessel endothelial cells (rBMECs) and transport of PB across the rBMEC monolayer from apical to basolateral and basolateral to apical were evaluated in the presence of VER. The effect of VER on PB pharmacological activity on the central nervous system (CNS) and brain distribution of PB in mice were further investigated. The results showed that VER regulated the uptake of PB by rBMECs in a concentration-dependently biphasic manner. The uptake of PB by rBMECs was decreased by low concentrations of VER (1-25 μΜ), but increased by high concentrations of VER (50-300 μM). The biphasic regulation was also observed in transport experiment. In vivo studies showed that VER altered the pharmacological effect of PB on CNS and brain concentration of PB in a biphasic manner. In contrast to low doses of VER (0.125-0.5 mg/kg) that shortened the duration time of PB-induced loss of the righting reflex, high doses of VER (2-4 mg/kg) prolonged the duration time. Further study demonstrated that brain concentration of PB was decreased by 0.125 mg/kg VER, but increased by 2 mg/kg VER. The concentration-dependently biphasic regulation was also confirmed in the uptake of rhodamine 123 by rBMECs. Our results suggested that VER may regulate the transport of PB across BBB in a concentration-dependently biphasic manner and the biphasic regulation may be involved in P-gp function.

  6. Postantibiotic effect of ceftaroline against gram-positive organisms.

    PubMed

    Pankuch, G A; Appelbaum, P C

    2009-10-01

    The postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects (SMEs) of ceftaroline, a novel injectable cephalosporin, were determined for 15 gram-positive organisms. The pneumococcal, staphylococcal, and enterococcal PAEs were 0.8 to 1.8 h, 0.7 to 2.2 h, and 0.2 to 1.1 h, respectively. The corresponding PA-SMEs (0.4 times the MIC) were 2.5 to 6.7 h, 2.9 to >0.0 h, and 7.9 to >10.3 h, respectively. The PA-SMEs were longer than the PAEs, suggesting that sub-MIC levels extend the PAE of ceftaroline against gram-positive cocci.

  7. A biphasic basal body temperature record during pregnancy.

    PubMed

    Urman, B C; McComb, P F

    1989-01-01

    A case of biphasic temperature record is reported during the course of an ectopic pregnancy. Possible implications of this phenomenon may improve our understanding of the role of ovum transmigration and the endocrinological interaction of pregnancy with hormonal control of ovulation.

  8. TREATMENT OF TYPE 2 DIABETES WITH BIPHASIC INSULIN ANALOGUES

    PubMed Central

    Rizvi, Ali A.

    2016-01-01

    The majority of patients with Type 2 diabetes require insulin therapy for treating hyperglycaemia. There are several regimens available for insulin initiation and maintenance. Insulin analogues have been developed to mimic normal physiology as closely as possible. Biphasic analogues can target both fasting and postprandial hyperglycaemia, with the added advantage of being premixed and thus convenient for the patient. A practical and feasible option is to initiate insulin with one or more biphasic preparations at mealtimes, thus providing both basal and prandial coverage. Individual titration of dose and frequency of daily injections with biphasic insulin preparations has the potential for improving glycaemic control with a high degree of patient acceptance. Drawbacks include a more rigid regimen, a relative lack of flexibility, and a somewhat higher degree of glycaemic variability and hypoglycaemia when compared to multiple daily basal-bolus injections. Awareness of the advantages and limitations of biphasic insulin analogues can assist clinicians in their appropriate use for the treatment of patients with Type 2 diabetes. PMID:27918600

  9. Bi-phase transition diagrams of metallic thin multilayers

    SciTech Connect

    Li, J.C.; Liu, W.; Jiang, Q. . E-mail: jiangq@jlu.edu.cn

    2005-02-01

    Phase transitions of metallic multilayers induced by differences in interface energy are considered thermodynamically, based on a thermodynamic model for interface energy and the Goldschmidt premise for lattice contraction. Bi-phase transition diagrams of Co/Cr, Zr/Nb, Ti/Nb and Ti/Al multilayers are constructed, which are in agreement with experimental results.

  10. Efficacy and safety of biphasic insulin aspart and biphasic insulin lispro mix in patients with type 2 diabetes: A review of the literature

    PubMed Central

    Kumar, Ajay

    2016-01-01

    Type 2 diabetes (T2D) represents an escalating burden worldwide, particularly in China and India. Compared with Caucasians, Asian people with diabetes have lower body mass index, increased visceral adiposity, and postprandial glucose (PPG)/insulin resistance. Since postprandial hyperglycemia contributes significantly to total glycemic burden and is associated with heightened cardiovascular risk, targeting PPG early in T2D is paramount. Premixed insulin regimens are widely used in Asia due to their convenience and effectiveness. Data from randomized controlled trials and observational studies comparing efficacy and safety of biphasic insulin aspart 30 (BIAsp 30) with biphasic insulin lispro mix (LM 25/50) and versus other insulin therapies or oral antidiabetic drugs (OADs) in T2D demonstrated that BIAsp 30 and LM 25/50 were associated with similar or greater improvements in glycemic control versus comparator regimens, such as basal–bolus insulin, in insulin-naÏve, and prior insulin users. Studies directly comparing BIAsp 30 and LM 25 provided conflicting glycemic control results. Safety data generally showed increased hypoglycemia and weight gain with premixed insulins versus basal–bolus insulin or OADs. However, large observational trials documented improvements in glycated hemoglobin, PPG, and hypoglycemia with BIAsp 30 in multi-ethnic patient populations. In summary, this literature review demonstrates that premixed insulin regimens are an appropriate and effective treatment choice in T2D. PMID:27186543

  11. Torsion effects on a relativistic position-dependent mass system

    NASA Astrophysics Data System (ADS)

    Vitória, R. L. L.; Bakke, K.

    2016-12-01

    We analyse a relativistic scalar particle with a position-dependent mass in a spacetime with a space-like dislocation by showing that relativistic bound states solutions can be achieved. Further, we consider the presence of the Coulomb potential and analyse the relativistic position-dependent mass system subject to the Coulomb potential in the spacetime with a space-like dislocation. We also show that a new set of relativistic bound states solutions can be obtained, where there also exists the influence of torsion of the relativistic energy levels. Finally, we investigate an analogue of the Aharonov-Bohm effect for bound states in this position-dependent mass in a spacetime with a space-like dislocation.

  12. Asymmetric effects of positive and negative affect on decision making.

    PubMed

    Cahir, Caitriona; Thomas, Kevin

    2010-02-01

    Although affect is a fundamental element of decision making, there are different theoretical accounts and conflicting empirical evidence of its influence. This experiment was done to begin a more coherent account of the influence of affect by using standardised images to induce affect and a betting task to measure decision making. Eighty-five participants were assigned to a positive, a negative, or a neutral affect condition before making decisions on two hypothetical horse races. Analysis indicated that those in the positive and negative conditions made lower-risk decisions than those in the neutral condition; however, this did not differ between the races, suggesting that task familiarity did not moderate the influence of affect. Contrary to previous research, these results indicate that positive and negative affect do not necessarily exert symmetrical effects on decision making. Implications for the major accounts of the influence of affect on decision making are discussed in relation to the findings.

  13. Position Verification for the Prostate: Effect on Rectal Wall Dose

    SciTech Connect

    Haverkort, Marie A.D.; Kamer, Jeroen B. van de; Pieters, Bradley R.; Tienhoven, Geertjan van; Assendelft, Esther; Lensing, Andrea L.; Herk, Marcel van; Reijke, Theo M. de; Stoker, Jaap; Koning, Caro C.E.

    2011-06-01

    Purpose: To evaluate the effect of gold marker (GM)-based position correction on the cumulative dose in the anorectal wall compared with traditional bony anatomy (BA)-based correction, taking into account changes in anorectal shape and position. Methods and Materials: A total of 20 consecutive prostate cancer patients, treated with curative external beam radiotherapy, were included. Four fiducial GMs were implanted in the prostate. Positioning was verified according to the shift in BA and GMs on daily electronic portal images. Position corrections were determined using on- and off-line position verification protocols according to the position of the GMs (GM-on and GM-off) and BA (BA-off). For all patients, intensity-modulated radiotherapy plans were made for the GM (8-mm planning target volume margin) and BA (10-mm planning target volume margin) protocols. The dose distribution was recomputed on 11 repeat computed tomography scans to estimate the accumulated dose to the prostate and anorectal wall while considering internal organ motion. Results: The dose that is at least received by 99% of the prostate was, on average, acceptable for all protocols. The individual patient data showed the best coverage for both GM protocols, with >95% of the prescribed dose for all patients. The anorectal wall dose was significantly lower for the GM protocols. The dose that is at least received by 30% of the rectal wall was, on average, 54.6 Gy for GM-on, 54.1 Gy for GM-off, and 58.9 Gy for BA-off (p <.001). Conclusion: Position verification with GM and reduced planning target volume margins yielded adequate treatment of the prostate and a lower rectal wall dose, even when accounting for independent movement of the prostate and anorectal wall.

  14. Atmospheric pressure loading effects on Global Positioning System coordinate determinations

    SciTech Connect

    Vandam, T.M.; Blewitt, G.; Heflin, M.B. ||

    1994-12-01

    Earth deformation signals caused by atmospheric pressure loading are detected in vertical position estimates at Global Positioning System (GPS) stations. Surface displacements due to changes in atmospheric pressure account for up to 24% of the total variance in the GPS height estimates. The detected loading signals are larger at higher latitudes where pressure variations are greatest; the largest effect is observed at Fairbanks, Alaska (latitude 65 deg), with a signal root mean square (RMS) of 5 mm. Out of 19 continuously operating GPS sites (with a mean of 281 daily solutions per site), 18 show a positive correlation between the GPS vertical estimates and the modeled loading displacements. Accounting for loading reduces the variance of the vertical station positions on 12 of the 19 sites investigated. Removing the modeled pressure loading from GPS determinations of baseline length for baselines longer than 6000 km reduces the variance on 73 of the 117 baselines investigated. The slight increase in variance for some of the sites and baselines is consistent with expected statistical fluctuations. The results from most stations are consistent with approximately 65% of the modeled pressure load being found in the GPS vertical position measurements. Removing an annual signal from both the measured heights and the modeled load time series leaves this value unchanged.

  15. Differential Effects of Arousal in Positive and Negative Autobiographical Memories

    PubMed Central

    Ford, Jaclyn Hennessey; Addis, Donna Rose; Giovanello, Kelly S.

    2014-01-01

    Autobiographical memories are characterized by a range of emotions and emotional reactions. Recent research has demonstrated that differences in emotional valence (positive v. negative emotion) and arousal (the degree of emotional intensity) differentially influence the retrieved memory narrative. Although the mnemonic effects of valence and arousal have both been heavily studied, it is currently unclear whether the effects of emotional arousal are equivalent for positive and negative autobiographical events. In the current study, multilevel models were used to examine differential effects emotional valence and arousal on the richness of autobiographical memory retrieval both between and within subjects. Thirty-four young adults were asked to retrieve personal autobiographical memories associated with popular musical cues and to rate the valence, arousal, and richness of these events. The multilevel analyses identified independent influences of valence and intensity upon retrieval characteristics at the within and between subject levels. In addition, the within subject interactions between valence and arousal highlighted differential effects of arousal for positive and negative memories. These findings have important implications for future studies of emotion and memory, highlighting the importance of considering both valence and arousal when examining the role emotion plays in the richness of memory representation. PMID:22873402

  16. The Age-related Positivity Effect and Tobacco Warning Labels

    PubMed Central

    Roberts, Megan E.; Peters, Ellen; Ferketich, Amy K.; Klein, Elizabeth G.

    2016-01-01

    Objectives This study tested whether age is a factor in viewing time for tobacco warning labels. The approach drew from previous work demonstrating an age-related positivity effect, whereby older adults show preferences toward positive and away from negative stimuli. Methods Participants were 295 daily smokers from Appalachian Ohio (age range: 21–68). All participants took part in an eye-tracking paradigm that captured the attention paid to elements of health warning labels in the context of magazine advertisements. Participants also reported on their past cessation attempts and their beliefs about the dangers of smoking. Results Consistent with theory on age-related positivity, older age predicted weaker beliefs about smoking risks, but only among those with no past-year quit attempts. In support of our primary hypothesis, older age was also related to a lower percentage of time spent viewing tobacco warning labels, both overall (text + image) and for the graphic image alone. These associations remained after controlling for cigarettes smoked per day. Conclusions Overall, findings suggest that age is an important consideration for the design of future graphic warning labels and other tobacco risk communications. For older adults, warning labels may need to be tailored to overcome the age-related positivity effect. PMID:27617273

  17. The Innuendo Effect: Hearing the Positive but Inferring the Negative

    PubMed Central

    Kervyn, Nicolas; Bergsieker, Hilary B.; Fiske, Susan T.

    2015-01-01

    Speakers can convey mixed impressions by providing only positive information. As a series of studies shows, when communicators omit information on a salient, relevant dimension of social perception, listeners make negative inferences about the target on that omitted dimension, despite directly receiving only positive information on another dimension (Studies 1 and 2a). These negative inferences mediated the effect of the innuendo manipulation on judgments about the target person's suitability for inclusion in one's group. Simulating communication, Study 2b participants read Study 2a's descriptions and showed this innuendo effect is stronger for descriptions of female as opposed to male targets in an academic domain. We discuss implications of innuendo for the communication and perpetuation of mixed impressions and their prevalence in descriptions of subordinate group members. PMID:26023243

  18. A Faraday effect position sensor for interventional magnetic resonance imaging.

    PubMed

    Bock, M; Umathum, R; Sikora, J; Brenner, S; Aguor, E N; Semmler, W

    2006-02-21

    An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.

  19. Differential Biphasic Transcriptional Host Response Associated with Coevolution of Hemagglutinin Quasispecies of Influenza A Virus

    PubMed Central

    Manchanda, Himanshu; Seidel, Nora; Blaess, Markus F.; Claus, Ralf A.; Linde, Joerg; Slevogt, Hortense; Sauerbrei, Andreas; Guthke, Reinhard; Schmidtke, Michaela

    2016-01-01

    Severe influenza associated with strong symptoms and lung inflammation can be caused by intra-host evolution of quasispecies with aspartic acid or glycine in hemagglutinin position 222 (HA-222D/G; H1 numbering). To gain insights into the dynamics of host response to this coevolution and to identify key mechanisms contributing to copathogenesis, the lung transcriptional response of BALB/c mice infected with an A(H1N1)pdm09 isolate consisting HA-222D/G quasispecies was analyzed from days 1 to 12 post infection (p.i). At day 2 p.i. 968 differentially expressed genes (DEGs) were detected. The DEG number declined to 359 at day 4 and reached 1001 at day 7 p.i. prior to recovery. Interestingly, a biphasic expression profile was shown for the majority of these genes. Cytokine assays confirmed these results on protein level exemplarily for two key inflammatory cytokines, interferon gamma and interleukin 6. Using a reverse engineering strategy, a regulatory network was inferred to hypothetically explain the biphasic pattern for selected DEGs. Known regulatory interactions were extracted by Pathway Studio 9.0 and integrated during network inference. The hypothetic gene regulatory network revealed a positive feedback loop of Ifng, Stat1, and Tlr3 gene signaling that was triggered by the HA-G222 variant and correlated with a clinical symptom score indicating disease severity. PMID:27536272

  20. The Optimal Viewing Position effect in the lower visual field.

    PubMed

    Yao-N'dré, Marina; Castet, Eric; Vitu, Françoise

    2013-01-14

    The Optimal Viewing Position (OVP) effect shows that word identification is best when the eyes first fixate near the centre of words. While this effect has been extensively studied in normal reading conditions, it has not been much investigated for words in the periphery. Here, we compared, in a perceptual identification task, the OVP effect for words presented either on the line of sight or in the lower visual field. Results confirmed the existence of an OVP effect for both central and vertically-shifted words but this effect was significantly weaker in the lower visual field. This finding provides further evidence for an important role of letter visibility in determining the shape of the OVP phenomenon. It also indicates that aligning the eyes with the centre of words is not as critical for vertically-shifted words. Implications for patients with central field loss who are forced to read in the periphery are discussed.

  1. Atmospheric pressure loading effects on Global Positioning System coordinate determinations

    NASA Technical Reports Server (NTRS)

    Vandam, Tonie M.; Blewitt, Geoffrey; Heflin, Michael B.

    1994-01-01

    Earth deformation signals caused by atmospheric pressure loading are detected in vertical position estimates at Global Positioning System (GPS) stations. Surface displacements due to changes in atmospheric pressure account for up to 24% of the total variance in the GPS height estimates. The detected loading signals are larger at higher latitudes where pressure variations are greatest; the largest effect is observed at Fairbanks, Alaska (latitude 65 deg), with a signal root mean square (RMS) of 5 mm. Out of 19 continuously operating GPS sites (with a mean of 281 daily solutions per site), 18 show a positive correlation between the GPS vertical estimates and the modeled loading displacements. Accounting for loading reduces the variance of the vertical station positions on 12 of the 19 sites investigated. Removing the modeled pressure loading from GPS determinations of baseline length for baselines longer than 6000 km reduces the variance on 73 of the 117 baselines investigated. The slight increase in variance for some of the sites and baselines is consistent with expected statistical fluctuations. The results from most stations are consistent with approximately 65% of the modeled pressure load being found in the GPS vertical position measurements. Removing an annual signal from both the measured heights and the modeled load time series leaves this value unchanged. The source of the remaining discrepancy between the modeled and observed loading signal may be the result of (1) anisotropic effects in the Earth's loading response, (2) errors in GPS estimates of tropospheric delay, (3) errors in the surface pressure data, or (4) annual signals in the time series of loading and station heights. In addition, we find that using site dependent coefficients, determined by fitting local pressure to the modeled radial displacements, reduces the variance of the measured station heights as well as or better than using the global convolution sum.

  2. Positive and negative recency effects in retirement savings decisions.

    PubMed

    Rieskamp, Jörg

    2006-12-01

    Retirement savings decisions can be influenced by the fund composition of the retirement savings plan. In 2 experiments, strong composition effects were observed, with a larger percentage of resources being invested in stock funds when more stock than bond funds were offered. Although participants changed their allocations repeatedly, the opportunity to learn did not alter the composition effects. Learning processes led to positive and negative recency effects as well, providing evidence that allocations were strongly influenced by the recent performance of the different allocation options. Two learning models were tested to explain these learning processes. The first, a local adaptation learning model, assumes that people change their behavior on the basis of recent experience, whereas the second, a reinforcement learning model, assumes that decisions are made on the basis of the totality of accumulated experience. The local adaptation model was more accurate in predicting allocation decisions, in explaining positive and negative recency effects, and in showing why composition effects are not overcome by learning.

  3. Genomic imprinting and position-effect variegation in Drosophila melanogaster.

    PubMed Central

    Lloyd, V K; Sinclair, D A; Grigliatti, T A

    1999-01-01

    Genomic imprinting is a phenomenon in which the expression of a gene or chromosomal region depends on the sex of the individual transmitting it. The term imprinting was first coined to describe parent-specific chromosome behavior in the dipteran insect Sciara and has since been described in many organisms, including other insects, plants, fish, and mammals. In this article we describe a mini-X chromosome in Drosophila melanogaster that shows genomic imprinting of at least three closely linked genes. The imprinting of these genes is observed as mosaic silencing when the genes are transmitted by the male parent, in contrast to essentially wild-type expression when the same genes are maternally transmitted. We show that the imprint is due to the sex of the parent rather than to a conventional maternal effect, differential mitotic instability of the mini-X chromosome, or an allele-specific effect. Finally, we have examined the effects of classical modifiers of position-effect variegation on the maintenance and the establishment of the imprint. Factors that modify position-effect variegation alter the somatic expression but not the establishment of the imprint. This suggests that chromatin structure is important in maintenance of the imprint, but a separate mechanism may be responsible for its initiation. PMID:10101173

  4. Resolving the limb position effect in myoelectric pattern recognition.

    PubMed

    Fougner, Anders; Scheme, Erik; Chan, Adrian D C; Englehart, Kevin; Stavdahl, Oyvind

    2011-12-01

    Reported studies on pattern recognition of electromyograms (EMG) for the control of prosthetic devices traditionally focus on classification accuracy of signals recorded in a laboratory. The difference between the constrained nature in which such data are often collected and the unpredictable nature of prosthetic use is an example of the semantic gap between research findings and a viable clinical implementation. In this paper, we demonstrate that the variations in limb position associated with normal use can have a substantial impact on the robustness of EMG pattern recognition, as illustrated by an increase in average classification error from 3.8% to 18%. We propose to solve this problem by: 1) collecting EMG data and training the classifier in multiple limb positions and by 2) measuring the limb position with accelerometers. Applying these two methods to data from ten normally limbed subjects, we reduce the average classification error from 18% to 5.7% and 5.0%, respectively. Our study shows how sensor fusion (using EMG and accelerometers) may be an efficient method to mitigate the effect of limb position and improve classification accuracy.

  5. Positive interpretation training: effects of mental imagery versus verbal training on positive mood.

    PubMed

    Holmes, Emily A; Mathews, Andrew; Dalgleish, Tim; Mackintosh, Bundy

    2006-09-01

    Therapists often assume a special association between mental imagery and emotion, though empirical evidence has been lacking. Using an interpretation training paradigm, we previously found that imagery had a greater impact on anxiety than did verbal processing of the same material (Holmes & Mathews, 2005). Although the finding of a differential impact of imagery versus verbal processing of negative material was replicated, findings did not extend to benign material. Results therefore left open the question of whether there may be a special association between imagery and positive emotion. The current experiment examined positive interpretation training. Numerous scenarios were presented with initial ambiguity as to positive outcome or not, with final information then yielding consistently positive resolutions. Participants were asked to either imagine these positive events or to listen to the same descriptions while thinking about their verbal meaning. Those participants in the imagery condition reported greater increases in positive affect and rated new descriptions as being more positive than did those in the verbal condition. Results suggest that positive training can be enhanced through imagery as opposed to verbal processing. This study also provides the first test of a standardized intervention using an "interpretive bias training" paradigm to improve positive mood.

  6. Regulation of positive and negative emotion: effects of sociocultural context

    PubMed Central

    Snyder, Sara A.; Heller, S. Megan; Lumian, Daniel S.; McRae, Kateri

    2013-01-01

    Previous research has demonstrated that the use of emotion regulation strategies can vary by sociocultural context. In a previous study, we reported changes in the use of two different emotion regulation strategies at an annual alternative cultural event, Burning Man (McRae et al., 2011). In this sociocultural context, as compared to typically at home, participants reported less use of expressive suppression (a strategy generally associated with maladaptive outcomes), and greater use of cognitive reappraisal (a strategy generally associated with adaptive outcomes). What remained unclear was whether these changes in self-reported emotion regulation strategy use were characterized by changes in the regulation of positive emotion, negative emotion, or both. We addressed this issue in the current study by asking Burning Man participants separate questions about positive and negative emotion. Using multiple datasets, we replicated our previous findings, and found that the decreased use of suppression is primarily driven by reports of decreased suppression of positive emotion at Burning Man. By contrast, the increased use of reappraisal is not characterized by differential reappraisal of positive and negative emotion at Burning Man. Moreover, we observed novel individual differences in the magnitude of these effects. The contextual changes in self-reported suppression that we observe are strongest for men and younger participants. For those who had previously attended Burning Man, we observed lower levels of self-reported suppression in both sociocultural contexts: Burning Man and typically at home. These findings have implications for understanding the ways in which certain sociocultural contexts may decrease suppression, and possibly minimize its associated maladaptive effects. PMID:23840191

  7. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    PubMed Central

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-01-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process. PMID:26843320

  8. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems.

    PubMed

    Passos, Helena; Luís, Andreia; Coutinho, João A P; Freire, Mara G

    2016-02-04

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  9. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    NASA Astrophysics Data System (ADS)

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-02-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  10. Biphasic mode of antibacterial action of aminoglycoside antibiotics-loaded elastic hydroxyapatite-glucan composite.

    PubMed

    Belcarz, Anna; Zima, Aneta; Ginalska, Grażyna

    2013-09-15

    Following the quest for new composite materials for bone tissue engineering, a novel elastic hydroxyapatite-glucan composite loaded with two aminoglycoside antibiotics was prepared. The porosity of the composite and the drug release profiles in closed-loop and semi-open systems were tested. The antibacterial activity of the drug was estimated against two Gram-positive and two Gram-negative bacterial strains causing orthopedic infections. It was found that the loaded antibiotic acted in a biphasic mode. The majority of the drug was released within 48-119 h in a pore-dependent manner and inhibited the bacterial growth in the culture medium. However, a small residual amount of the drug was bound to the composite microstructure via ionic interactions and acted as a short-lived barrier against bacterial adhesion to the composite, although the surrounding medium was no longer protected against bacterial infection. Sub-inhibitory concentrations of the released drug were observed in the medium only during the last two days of the experiment (minimized risk of occurrence of drug-resistant strains). Thus the novel drug-loaded elastic hydroxyapatite-glucan composite, demonstrating a biphasic mode of antibacterial action, may be recommended for antibiotic prophylaxis in bone substitute implantation, with less emphasis on the treatment of bone infections.

  11. Primary Esophageal Extranasal NK/T Cell Lymphoma With Biphasic Morphology

    PubMed Central

    Ye, Zi-Yin; Cao, Qing-Hua; Liu, Fang; Lu, Xiao-Fang; Li, Shu-Rong; Li, Chang-Zhao; Chen, Shao-Hong

    2015-01-01

    Abstract We report a case of esophageal extranasal NK/T cell lymphoma with biphasic morphologic features revealed by a deep large piecemeal biopsy. A 40-year-old man present with pharyngalgia, dysphagia, recurrent fever, and 5-kg weight loss for 8 months. Endoscopy demonstrated progressing longitudinal ulcers and mucosal bridges along the esophagus. The first and second biopsies obtained superficial mucosa with scattered bland-looking small lymphocytes. A subsequent large piecemeal snare abscission for biopsy showed atypical lymphoid cells infiltrating into the deep lamina propria and muscularis mucosae, whereas the superficial lamina propria was highly edematous with scant small lymphocytes. Immunohistochemical studies confirmed that both underlying atypical cells and superficial small lymphocytes were neoplastic, sharing an identical immunophenotype: positive for CD2, CD3, CD43, CD8, CD56, TIA-1 and granzyme B. Epstein-Barr virus–encoded small RNAs were found in both cells. The histologic findings were diagnostic of primary esophageal extranasal NK/T cell lymphoma. However, the patient developed bone marrow depression during chemotherapy and died of massive cerebral hemorrhage after the first cycle of chemotherapy. Primary esophageal extranodal NK/T cell lymphoma nasal type is extremely rare. We show the biphasic morphology of this disease, which highlights the importance of deep biopsy for accurate diagnosis. PMID:26181557

  12. Biphasic recruitment of microchimeric fetal mesenchymal cells in fibrosis following acute kidney injury.

    PubMed

    Roy, Edwige; Seppanen, Elke; Ellis, Rebecca; Lee, Eddy S; Khosrotehrani, Kiarash; Khosroterani, Kiarash; Fisk, Nicholas M; Bou-Gharios, George

    2014-03-01

    Fetal microchimeric cells (FMCs) enter the maternal circulation and persist in tissue for decades. They have capacity to home to injured maternal tissue and differentiate along that tissue's lineage. This raises the question of the origin(s) of cells transferred to the mother during pregnancy. FMCs with a mesenchymal phenotype have been documented in several studies, which makes mesenchymal stem cells an attractive explanation for their broad plasticity. Here we assessed the recruitment and mesenchymal lineage contribution of FMCs in response to acute kidney fibrosis induced by aristolochic acid injection. Serial in vivo bioluminescence imaging revealed a biphasic recruitment of active collagen-producing FMCs during the repair process of injured kidney in post-partum wild-type mothers that had delivered transgenic pups expressing luciferase under the collagen type I-promoter. The presence of FMCs long-term post injury (day 60) was associated with profibrotic molecules (TGF-β/CTGF), serum urea levels, and collagen deposition. Immunostaining confirmed FMCs at short term (day 15) using post-partum wild-type mothers that had delivered green fluorescent protein-positive pups and suggested a mainly hematopoietic phenotype. We conclude that there is biphasic recruitment to, and activity of, FMCs at the injury site. Moreover, we identified five types of FMC, implicating them all in the reparative process at different stages of induced renal interstitial fibrosis.

  13. Patient position alters attenuation effects in multipinhole cardiac SPECT

    SciTech Connect

    Timmins, Rachel; Ruddy, Terrence D.; Wells, R. Glenn

    2015-03-15

    Purpose: Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Methods: Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Results: Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of <1.5 for the water phantom but up to 4.2 in the anthropomorphic phantom. Changes were larger for axial than for transverse translations. These results were supported by SPS changes of up to six seen in the physical anthropomorphic phantom for axial translations. Defect width was also seen to significantly increase. The

  14. Aerobic Exercise Decreases the Positive-Reinforcing Effects of Cocaine

    PubMed Central

    Smith, Mark A.; Schmidt, Karl T.; Iordanou, Jordan C.; Mustroph, Martina L.

    2008-01-01

    Aerobic exercise can serve as an alternative, non-drug reinforcer in laboratory animals and has been recommended as a potential intervention for substance abusing populations. Unfortunately, relatively little empirical data have been collected that specifically address the possible protective effects of voluntary, long-term exercise on measures of drug self-administration. The purpose of the present study was to examine the effects of chronic exercise on sensitivity to the positive-reinforcing effects of cocaine in the drug self-administration procedure. Female rats were obtained at weaning and immediately divided into two groups. Sedentary rats were housed individually in standard laboratory cages that permitted no exercise beyond normal cage ambulation; exercising rats were housed individually in modified cages equipped with a running wheel. After 6 weeks under these conditions, rats were surgically implanted with venous catheters and trained to self-administer cocaine on a fixed-ratio schedule of reinforcement. Once self-administration was acquired, cocaine was made available on a progressive ratio schedule and breakpoints were obtained for various doses of cocaine. Sedentary and exercising rats did not differ in the time to acquire cocaine self-administration or responding on the fixed-ratio schedule of reinforcement. However, on the progressive ratio schedule, breakpoints were significantly lower in exercising rats than sedentary rats when responding was maintained by both low (0.3 mg/kg/infusion) and high (1.0 mg/kg/infusion) doses of cocaine. In exercising rats, greater exercise output prior to catheter implantation was associated with lower breakpoints at the high dose of cocaine. These data indicate that chronic exercise decreases the positive-reinforcing effects of cocaine and support the possibility that exercise may be an effective intervention in drug abuse prevention and treatment programs. PMID:18585870

  15. Bioabsorbable zinc ion induced biphasic cellular responses in vascular smooth muscle cells

    PubMed Central

    Ma, Jun; Zhao, Nan; Zhu, Donghui

    2016-01-01

    Bioabsorbable metal zinc (Zn) is a promising new generation of implantable scaffold for cardiovascular and orthopedic applications. In cardiovascular stent applications, zinc ion (Zn2+) will be gradually released into the surrounding vascular tissues from such Zn-containing scaffolds after implantation. However, the interactions between vascular cells and Zn2+ are still largely unknown. We explored the short-term effects of extracellular Zn2+ on human smooth muscle cells (SMCs) up to 24 h, and an interesting biphasic effect of Zn2+ was observed. Lower concentrations (<80 μM) of Zn2+ had no adverse effects on cell viability but promoted cell adhesion, cell spreading, cell proliferation, cell migration, and enhanced the expression of F-actin and vinculin. Cells treated with such lower concentrations of Zn2+ displayed an elongated shape compared to controls without any treatment. In contrast, cells treated with higher Zn2+ concentrations (80–120 μM) had opposite cellular responses and behaviors. Gene expression profiles revealed that the most affected functional genes were related to angiogenesis, inflammation, cell adhesion, vessel tone, and platelet aggregation. Results indicated that Zn has interesting concentration-dependent biphasic effects on SMCs with low concentrations being beneficial to cellular functions. PMID:27248371

  16. Positive effects of vegetation: urban heat island and green roofs.

    PubMed

    Susca, T; Gaffin, S R; Dell'osso, G R

    2011-01-01

    This paper attempts to evaluate the positive effects of vegetation with a multi-scale approach: an urban and a building scale. Monitoring the urban heat island in four areas of New York City, we have found an average of 2 °C difference of temperatures between the most and the least vegetated areas, ascribable to the substitution of vegetation with man-made building materials. At micro-scale, we have assessed the effect of surface albedo on climate through the use of a climatological model. Then, using the CO(2) equivalents as indicators of the impact on climate, we have compared the surface albedo, and the construction, replacement and use phase of a black, a white and a green roof. By our analyses, we found that both the white and the green roofs are less impactive than the black one; with the thermal resistance, the biological activity of plants and the surface albedo playing a crucial role.

  17. [Caloric restriction: about its positive metabolic effects and cellular impact].

    PubMed

    Ortiz-Bautista, Raúl Julián; Aguilar-Salinas, Carlos Alberto; Monroy-Guzmán, Adriana

    2013-01-01

    Caloric restriction, as a 30 to 60% decrease of ad libitum balanced caloric intake, without malnutrition, is the non-genetic strategy that has consistently extended the average and maximum lifespan of most living beings, and it has been tested from unicellular organisms like yeast Saccharomyces cerevisiae to Rhesus primates. In addition, various genetic and pharmacological caloric restriction models have shown to protect against cancer, cardiovascular and neurodegenerative diseases. Primate studies suggest that this intervention delays the onset of age-related diseases; in humans, it has physiological, biochemical and metabolic effects decreasing diabetes and cardiovascular disease risk factor. Although currently the mechanism by which caloric restriction has its positive effects at the cellular level is unknown, it has been reported to decrease oxidative stress and increase in mitochondrial biogenesis.

  18. Mutual positive effects between shrubs in an arid ecosystem

    PubMed Central

    Tirado, Reyes; Bråthen, Kari Anne; Pugnaire, Francisco I.

    2015-01-01

    One-way facilitation in plants has been found in many harsh environments and their role as structural forces governing species composition in plant communities is now well established. However, reciprocal positive effects benefiting two interacting species have seldom been reported and, in recent reviews, conceptually considered merely as facilitation when in fact there is room for adaptive strategies and evolutionary responses. We tested the existence of such reciprocal positive effects in an arid environment in SE Spain using spatial pattern analysis, a species removal experiment, and a natural experiment. We found that the spatial association between Maytenus senegalensis and Whitania frutescens, two shrub species of roughly similar size intimately interacting in our community, resulted in mutual benefit for both species. Benefits included improved water relations and nutritional status and protection against browsing, and did occur despite simultaneous competition for resources. Our data suggest two-way facilitation or, rather, a facultative mutualism among higher plant species, a process often overlooked which could be a main driver of plant community dynamics allowing for evolutionary processes. PMID:26419958

  19. Resource distribution influences positive edge effects in a seagrass fish.

    PubMed

    Macreadie, Peter I; Hindell, Jeremy S; Keough, Michael J; Jenkins, Gregory P; Connolly, Rod M

    2010-07-01

    According to conceptual models, the distribution of resources plays a critical role in determining how organisms distribute themselves near habitat edges. These models are frequently used to achieve a mechanistic understanding of edge effects, but because they are based predominantly on correlative studies, there is need for a demonstration of causality, which is best done through experimentation. Using artificial seagrass habitat as an experimental system, we determined a likely mechanism underpinning edge effects in a seagrass fish. To test for edge effects, we measured fish abundance at edges (0-0.5 m) and interiors (0.5-1 m) of two patch configurations: continuous (single, continuous 9-m2 patches) and patchy (four discrete 1-m2 patches within a 9-m2 area). In continuous configurations, pipefish (Stigmatopora argus) were three times more abundant at edges than interiors (positive edge effect), but in patchy configurations there was no difference. The lack of edge effect in patchy configurations might be because patchy seagrass consisted entirely of edge habitat. We then used two approaches to test whether observed edge effects in continuous configurations were caused by increased availability of food at edges. First, we estimated the abundance of the major prey of pipefish, small crustaceans, across continuous seagrass configurations. Crustacean abundances were highest at seagrass edges, where they were 16% greater than in patch interiors. Second, we supplemented interiors of continuous treatment patches with live crustaceans, while control patches were supplemented with seawater. After five hours of supplementation, numbers of pipefish were similar between edges and interiors of treatment patches, while the strong edge effects were maintained in controls. This indicated that fish were moving from patch edges to interiors in response to food supplementation. These approaches strongly suggest that a numerically dominant fish species is more abundant at seagrass

  20. Engineering amount of cell-cell contact demonstrates biphasic proliferative regulation through RhoA and the actin cytoskeleton

    SciTech Connect

    Gray, Darren S.; Liu, Wendy F.; Shen, Colette J.; Bhadriraju, Kiran; Nelson, Celeste M.; Chen, Christopher S.

    2008-09-10

    Endothelial cell-cell contact via VE-cadherin plays an important role in regulating numerous cell functions, including proliferation. However, using different experimental approaches to manipulate cell-cell contact, investigators have observed both inhibition and stimulation of proliferation depending on the adhesive context. In this study, we used micropatterned wells combined with active positioning of cells by dielectrophoresis in order to investigate whether the number of contacting neighbors affected the proliferative response. Varying cell-cell contact resulted in a biphasic effect on proliferation; one contacting neighbor increased proliferation, while two or more neighboring cells partially inhibited this increase. We also observed that cell-cell contact increased the formation of actin stress fibers, and that expression of dominant negative RhoA (RhoN19) blocked the contact-mediated increase in stress fibers and proliferation. Furthermore, examination of heterotypic pairs of untreated cells in contact with RhoN19-expressing cells revealed that intracellular, but not intercellular, tension is required for the contact-mediated stimulation of proliferation. Moreover, engagement of VE-cadherin with cadherin-coated beads was sufficient to stimulate proliferation in the absence of actual cell-cell contact. In all, these results demonstrate that cell-cell contact signals through VE-cadherin, RhoA, and intracellular tension in the actin cytoskeleton to regulate proliferation.

  1. The Rematee Bumper Belt(®) positional therapy device for snoring and obstructive sleep apnea: Positional effectiveness in healthy subjects.

    PubMed

    Matthews, Les; Fortier, Normand

    2013-01-01

    The present study was designed to investigate body position changes resulting from wearing a Rematee Bumper Belt (Rematee, Canada) during sleep. The majority of obstructive sleep apnea (OSA) patients will experience up to two times as many apneas and hypopneas while supine relative to lateral or prone body positions during sleep. It has been suggested that a positional therapy device could reduce the number of apneas and hypopneas in such patients. The present study was conducted to determine whether the Rematee Bumper Belt positional therapy device could prevent healthy subjects from sleeping in the supine position. Test subjects wore the belt for one to two nights. Each belt was equipped with an accelerometer that was used to measure the orientation of the belt relative to the horizontal plane. The results suggest that the belt creates an exclusion zone approximately 80° wide centred near the supine orientation, where subjects are effectively prevented to enter. Results of the present preliminary study suggests that the Rematee Bumper Belt positional therapy device is effective at limiting healthy subjects from sleeping in a supine position. The device appears to be most effective between 150° and 230°. A device with this capability may provide an inexpensive and potentially effective alternative treatment option for patients with OSA. This device has the capacity for reducing snoring and the apnea-hypopnea index in individuals with positional OSA.

  2. Regulation of the demographic structure in isomorphic biphasic life cycles at the spatial fine scale.

    PubMed

    Vieira, Vasco Manuel Nobre de Carvalho da Silva; Mateus, Marcos Duarte

    2014-01-01

    Isomorphic biphasic algal life cycles often occur in the environment at ploidy abundance ratios (Haploid:Diploid) different from 1. Its spatial variability occurs within populations related to intertidal height and hydrodynamic stress, possibly reflecting the niche partitioning driven by their diverging adaptation to the environment argued necessary for their prevalence (evolutionary stability). Demographic models based in matrix algebra were developed to investigate which vital rates may efficiently generate an H:D variability at a fine spatial resolution. It was also taken into account time variation and type of life strategy. Ploidy dissimilarities in fecundity rates set an H:D spatial structure miss-fitting the ploidy fitness ratio. The same happened with ploidy dissimilarities in ramet growth whenever reproductive output dominated the population demography. Only through ploidy dissimilarities in looping rates (stasis, breakage and clonal growth) did the life cycle respond to a spatially heterogeneous environment efficiently creating a niche partition. Marginal locations were more sensitive than central locations. Related results have been obtained experimentally and numerically for widely different life cycles from the plant and animal kingdoms. Spore dispersal smoothed the effects of ploidy dissimilarities in fertility and enhanced the effects of ploidy dissimilarities looping rates. Ploidy dissimilarities in spore dispersal could also create the necessary niche partition, both over the space and time dimensions, even in spatial homogeneous environments and without the need for conditional differentiation of the ramets. Fine scale spatial variability may be the key for the prevalence of isomorphic biphasic life cycles, which has been neglected so far.

  3. Positive Effects of Massage Therapy on a Patient with Narcolepsy

    PubMed Central

    Hill, Robyn; Baskwill, Amanda

    2013-01-01

    Purpose The purpose of this case report was to investigate the effects of massage therapy on the sleep patterns of a woman with narcolepsy. Participant The 23-year-old woman’s primary symptoms included excessive daytime sleepiness and periodic leg movements (PLM), which were associated with her diagnoses of both narcolepsy and cataplexy. Intervention Five 45-minute massage therapy treatments were administered over a five-week period. The patient’s sleep patterns were recorded each week before the treatment. A final measurement was recorded in the sixth week. The sleep patterns were monitored using the Leeds Sleep Evaluation Questionnaire, which included ten visual analogue scales. Results The results of this case report included an improvement in getting to sleep by 148%, an improvement in quality of sleep by 1100%, an improvement in awake following sleep by 121%, and an improvement in behaviour following wakening by 28% using the Leeds Sleep Evaluation Questionnaire. Conclusion This case report suggests that massage therapy had a positive effect on this patient with narcolepsy. Further research is needed to investigate the effects of massage therapy on narcolepsy and sleep patterns. PMID:23730398

  4. Aging and the optimal viewing position effect in Chinese.

    PubMed

    Liu, Pingping; Liu, Danlu; Han, Buxin; Paterson, Kevin B

    2015-01-01

    Substantial evidence indicates that where readers fixate within a word affects the efficiency with which that word is recognized. Indeed, words in alphabetic languages (e.g., English, French) are recognized most efficiently when fixated at their optimal viewing position (OVP), which is near the word center. However, little is known about the effects of fixation location on word recognition in non-alphabetic languages, such as Chinese. Moreover, studies to date have not investigated if effects of fixation location vary across adult age-groups, although it is well-established that older readers experience greater difficulty recognizing words due to visual and cognitive declines. Accordingly, the present research examined OVP effects by young and older adult readers when recognizing Chinese words presented in isolation. Most words in Chinese are formed from two or more logograms called characters and so the present experiment investigated the influence of fixation location on the recognition of 2-, 3-, and 4-character words (and nonwords). The older adults experienced generally greater word recognition difficulty. But whereas the young adults recognized words most efficiently when initially fixating the first character of 2-character words and second character of 3- and 4-character words, the older adults recognized words most efficiently when initially fixating the first character for words of each length. The findings therefore reveal subtle but potentially important adult age differences in the effects of fixation location on Chinese word recognition. Moreover, the similarity in effects for words and nonwords implies a more general age-related change in oculomotor strategy when processing Chinese character-strings.

  5. Phosphorus-doped TiO2 catalysts with stable anatase-brookite biphase structure: synthesis and photocatalytic performance.

    PubMed

    Feng, Huajun; Zhang, Min-Hong; Yu, Liya E

    2013-07-01

    Phosphorus-doped (P-doped) TiO2 catalysts with a stable anatase-brookite biphase structure were successfully synthesized by integrating ultrasonication with phosphorus doping and Pluronic P123 surfactant. The synthesized catalysts were characterized using X-ray diffraction, transmission electron microscopy, nitrogen adsorption-desorption, Fourier transform infrared, and UV-visible diffuse reflectance spectra. Ultrasonication facilitates the appearance of brookite phase. Phosphorus doping was demonstrated an effective strategy to stabilize the anatase-brookite biphase structure and inhibits undesirable grain growth. Triblock copolymer Pluronic P123 used in the reaction facilitates the formation of catalyst particles with mesoporous structure and large surface area and prevents particles from agglomeration. The low band-gap of brookite phase enables the synthesized P-doped TiO2 catalysts outperform commercial P25 TiO2 and N-doped TiO2 in the degradation of methylene blue under both solar light and visible light irradiation.

  6. Positioning the Co-op Program for Maximum Marketing Effectiveness.

    ERIC Educational Resources Information Center

    Harris, Ronald R.

    1983-01-01

    Examines the concept of positioning, which is the way that individuals perceive and are made aware of a program and believe in its benefit to them and its application to cooperative education programs. Includes a five-step plan for assessing the position of cooperative programs and six ways to implement a positioning strategy. (JOW)

  7. Indentation Analysis of Biphasic Viscoelastic Hydrogels

    PubMed Central

    Toohey, K.S.; Kalyanam, S.; Palaniappan, J.; Insana, M.F.

    2015-01-01

    Mechanical properties of soft biological materials are dependent on the responses of the two phases of which they are comprised: the solid matrix and interstitial fluid. Indentation techniques are commonly used to measure properties of such materials, but comparisons between different experimental and analytical techniques can be difficult. Most models relating load and time during spherical indentation are based on Hertzian contact theory, but the exact limitation of this theory for soft materials are unclear. Here, we examine the response of gelatin hydrogels to shear and indentation loading to quantify combined effects of the solid and fluid phases. The instantaneous behavior of the hydrogels is different for each test geometry and loading rate, but the relaxed response, measured by the relaxed modulus, is the same for all tests, within 17%. Additionally, indentation depths from 15–25% of the radius of the spherical indenter are found to minimize error in the estimate of relaxed modulus. PMID:26568646

  8. Investigation of biphasic tumor oxygen dynamics induced by hyperoxic gas intervention: the dynamic phantom approach

    NASA Astrophysics Data System (ADS)

    Kim, Jae G.; Liu, Hanli

    2008-01-01

    We have developed dynamic tumor vascular phantoms and utilized them to investigate the biphasic behavior of increases in light absorption, which is directly associated with oxygenated hemoglobin concentration that was observed in vivo from rat breast tumor experiments during carbogen/oxygen inhalation. The experimental setup for the phantom study included a continuous-wave, multichannel, near-infrared spectroscopy (NIRS) system and syringe pumps to drive the simulated blood through the dynamic vascular phantoms. The results from such phantom experiments clearly show that the two time constants observed in tumor oxygenation dynamics in vivo can result from two different perfusion rates or two different blood flow velocities. We provide experimental support for our previous hypothesis: the biphasic tumor hemodynamic feature stems from a well-perfused and poorly perfused region that could be detected with the two time constants of the NIRS signals. With a multichannel approach, noninvasive NIRS measurements may have useful and prognostic values to quantify the therapeutic effects of cancer treatments.

  9. Biopolymer-stabilized Pt nanoparticles colloid: a highly active and recyclable catalyst for biphasic catalysis

    NASA Astrophysics Data System (ADS)

    Wang, Yujia; Shen, Yueyue; Qiu, Yunfei; Zhang, Ting; Liao, Yang; Zhao, Shilin; Ma, Jun; Mao, Hui

    2016-10-01

    Noble metal nanoparticles are promising candidates to replace conventional bulk counterparts owing to their high activity and selectivity. To enable catalyst recovery, noble metal nanoparticles are often supported onto solid matrices to prepare heterogeneous catalyst. Although recycle of noble metal nanoparticles is realized by heterogenization, a loss of activity is usually encountered. In the present investigation, Pt nanoparticles with tunable particle size (1.85-2.80 nm) were facilely prepared by using polyphenols as amphiphilic stabilizers. The as-prepared Pt nanoparticles colloid solution could be used as highly active catalyst in aqueous-organic biphasic catalysis. The phenolic hydroxyls of polyphenols could constrain Pt nanoparticles in aqueous phase, and simultaneously, the aromatic scaffold of polyphenols ensured effective interactions between substrates and Pt nanoparticles. As a consequence, the obtained polyphenols-stabilized Pt nanoparticles exhibited high activity and cycling stability in biphasic hydrogenation of a series of unsaturated compounds. Compared with conventional heterogeneous Pt-C and Pt-Al2O3 catalysts, polyphenols-stabilized Pt nanoparticles showed obvious advantage both in activity and cycling stability.

  10. Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Sartore, Luciana; Pandini, Stefano; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as superabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., polymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic products. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular distribution of particles, with diameter ranging from 5 to 10 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating that cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles which induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents and chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.

  11. The positive effect of skin transpiration in peach fruit growth.

    PubMed

    Morandi, Brunella; Manfrini, Luigi; Losciale, Pasquale; Zibordi, Marco; Corelli-Grappadelli, Luca

    2010-09-01

    The effect of fruit transpiration on the mechanisms driving peach (Prunus persica (L.) Batsch) daily growth was investigated. In peach, fruit water losses increase during the season and might play a key role in determining fruit growth. Skin transpiration was reduced during the cell expansion stage by enclosing fruit in plastic bags fitted with holes. In the first year, diameter changes of bagged and control fruit were precisely monitored for 15 days, and percentage dry matter and soluble solids content were determined during the experiment and at harvest. In the second year, midday fruit water potential, daily patterns of fruit growth and of vascular and transpiration flows were monitored. Bagging reduced fruit daily growth on some days, and negatively affected both fruit dry matter percentage and soluble solids content. Fruit transpiration rate was reduced during the midday hours, thus increasing midday fruit water potential and lowering xylem inflows. In accordance with the Münch hypothesis on traslocation, these conditions likely decreased the necessary gradient needed for the transport of phloem sap to sink organs, as in the afternoon, bagged fruit showed lower phloem inflows. These data suggest that skin transpiration in peach has a positive effect on fruit growth, as it enhances fruit phloem import.

  12. Prioritizing positivity: an effective approach to pursuing happiness?

    PubMed

    Catalino, Lahnna I; Algoe, Sara B; Fredrickson, Barbara L

    2014-12-01

    A decade of research reveals the benefits of positive emotions for mental and physical health; however, recent empirical work suggests the explicit pursuit of happiness may backfire. The present study hypothesized that the pursuit of happiness is not inherently self-defeating; in particular, individuals who seek positivity, as exemplified by how they make decisions about how to organize their day-to-day lives, may be happier. This individual difference is labeled prioritizing positivity. In a community sample of young to older adults (N = 233), prioritizing positivity predicted a host of well-being outcomes (positive emotions, depressive symptomology). In addition, people high in prioritizing positivity have greater resources, and these links are explained by more frequent experiences of positive emotions. In sum, the present study suggests that seeking happiness, although a delicate art, may be a worthwhile pursuit.

  13. Effect of position and time held in that position on ground-glass opacity in computed tomography images of dogs.

    PubMed

    Lee, Sang-Kwon; Park, Seungjo; Cheon, Byunggyu; Moon, Sohyeon; Hong, Sunghwa; Cho, Hyun; Chang, Dongwoo; Choi, Jihye

    2017-03-01

    OBJECTIVE To evaluate effects of position, time in that position, and positive end-expiratory pressure on ground-glass opacity caused by physiologic atelectasis on lung CT images and to determine effects of recumbency position before CT. ANIMALS 6 healthy Beagles. PROCEDURES In a crossover study, dogs were placed in 4 positions (sternal, dorsal, right lateral, and left lateral recumbency) for 2 holding times (30 and 60 minutes). Dogs were then repositioned in sternal recumbency, and CT was performed at 2 positive end-expiratory pressures (0 and 15 mm Hg). Location, distribution, and degree of ground-glass opacities were evaluated on lung CT images. Volume and mean density of the lungs and ground-glass opacities as well as maximum density of ground-glass opacities were evaluated. RESULTS Ground-glass opacities were mainly observed in parts of the lungs that were dependent during the various positions before CT, except for sternal recumbency. Opacities were reversible and decreased or disappeared after lung inflation. Ground-glass opacities were observed most frequently and had greatest severity when dogs were positioned in left lateral recumbency before CT. Ground-glass opacities were negligible for dogs positioned in sternal recumbency before CT. CONCLUSIONS AND CLINICAL RELEVANCE Location and reversibility of ground-glass opacities may help clinicians distinguish whether they are attributable to atelectasis or a result of pathological changes. Dogs should be positioned in sternal recumbency to minimize the occurrence of ground-glass opacities, particularly when several procedures are performed before CT, which increases the time that a dog will remain in the same position.

  14. The effect of micrococcal nuclease digestion on nucleosome positioning data.

    PubMed

    Chung, Ho-Ryun; Dunkel, Ilona; Heise, Franziska; Linke, Christian; Krobitsch, Sylvia; Ehrenhofer-Murray, Ann E; Sperling, Silke R; Vingron, Martin

    2010-12-29

    Eukaryotic genomes are packed into chromatin, whose basic repeating unit is the nucleosome. Nucleosome positioning is a widely researched area. A common experimental procedure to determine nucleosome positions involves the use of micrococcal nuclease (MNase). Here, we show that the cutting preference of MNase in combination with size selection generates a sequence-dependent bias in the resulting fragments. This strongly affects nucleosome positioning data and especially sequence-dependent models for nucleosome positioning. As a consequence we see a need to re-evaluate whether the DNA sequence is a major determinant of nucleosome positioning in vivo. More generally, our results show that data generated after MNase digestion of chromatin requires a matched control experiment in order to determine nucleosome positions.

  15. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis

    NASA Astrophysics Data System (ADS)

    Gomez, Virginia; Bear, Joseph C.; McNaughter, Paul D.; McGettrick, James D.; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R.; Dunnill, Charles W.

    2015-10-01

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co

  16. Positive and negative effects of IT on cancer registries.

    PubMed

    Mohammadzadeh, Niloofar; Safdari, Reza; Rahimi, Azin

    2013-01-01

    In the new millennium people are facing serious challenges in health care, especially with increasing non- communicable diseases (NCD). One of the most common NCDs is cancer which is the leading cause of death in developed countries and in developing countries is the second cause of death after heart diseases. Cancer registry can make possible the analysis, comparison and development of national and international cancer strategies and planning. Information technology has a vital role in quality improvement and facility of cancer registries. With the use of IT, in addition to gaining general benefits such as monitoring rates of cancer incidence and identifying planning priorities we can also gain specific advantages such as collecting information for a lifetime, creating tele medical records, possibility of access to information by patient, patient empowerment, and decreasing medical errors. In spite of the powerful role of IT, we confront various challenges such as general problems, like privacy of the patient, and specific problems, including possibility of violating patients rights through misrepresentation, omission of human relationships, and decrease in face to face communication between doctors and patients. By implementing appropriate strategies, such as identifying authentication levels, controlling approaches, coding data, and considering technical and content standards, we can optimize the use of IT. The aim of this paper is to emphasize the need for identifying positive and negative effects of modern IT on cancer registry in general and specific aspects as an approach to cancer care management.

  17. Optional contributions have positive effects for volunteering public goods games

    NASA Astrophysics Data System (ADS)

    Song, Qi-Qing; Li, Zhen-Peng; Fu, Chang-He; Wang, Lai-Sheng

    2011-11-01

    Public goods (PG) games with the volunteering mechanism are referred to as volunteering public goods (VPG) games, in which loners are introduced to the PG games, and a loner obtains a constant payoff but not participating the game. Considering that small contributions may have positive effects to encourage more players with bounded rationality to contribute, this paper introduces optional contributions (high value or low value) to these typical VPG games-a cooperator can contribute a high or low payoff to the public pools. With the low contribution, the logit dynamics show that cooperation can be promoted in a well mixed population comparing to the typical VPG games, furthermore, as the multiplication factor is greater than a threshold, the average payoff of the population is also enhanced. In spatial VPG games, we introduce a new adjusting mechanism that is an approximation to best response. Some results in agreement with the prediction of the logit dynamics are found. These simulation results reveal that for VPG games the option of low contributions may be a better method to stimulate the growth of cooperation frequency and the average payoff of the population.

  18. Design and development of a low-cost biphasic charge-balanced functional electric stimulator and its clinical validation

    PubMed Central

    Shendkar, Chandrashekhar; Lenka, Prasanna K.; Biswas, Abhishek; Kumar, Ratnesh

    2015-01-01

    Functional electric stimulators that produce near-ideal, charge-balanced biphasic stimulation waveforms with interphase delay are considered safer and more efficacious than conventional stimulators. An indigenously designed, low-cost, portable FES device named InStim is developed. It features a charge-balanced biphasic single channel. The authors present the complete design, mathematical analysis of the circuit and the clinical evaluation of the device. The developed circuit was tested on stroke patients affected by foot drop problems. It was tested both under laboratory conditions and in clinical settings. The key building blocks of this circuit are low dropout regulators, a DC–DC voltage booster and a single high-power current source OP-Amp with current-limiting capabilities. This allows the device to deliver high-voltage, constant current, biphasic pulses without the use of a bulky step-up transformer. The advantages of the proposed design over the currently existing devices include improved safety features (zero DC current, current-limiting mechanism and safe pulses), waveform morphology that causes less muscle fatigue, cost-effectiveness and compact power-efficient circuit design with minimal components. The device is also capable of producing appropriate ankle dorsiflexion in patients having foot drop problems of various Medical Research Council scale grades. PMID:26609419

  19. Design and development of a low-cost biphasic charge-balanced functional electric stimulator and its clinical validation.

    PubMed

    Shendkar, Chandrashekhar; Lenka, Prasanna K; Biswas, Abhishek; Kumar, Ratnesh; Mahadevappa, Manjunatha

    2015-10-01

    Functional electric stimulators that produce near-ideal, charge-balanced biphasic stimulation waveforms with interphase delay are considered safer and more efficacious than conventional stimulators. An indigenously designed, low-cost, portable FES device named InStim is developed. It features a charge-balanced biphasic single channel. The authors present the complete design, mathematical analysis of the circuit and the clinical evaluation of the device. The developed circuit was tested on stroke patients affected by foot drop problems. It was tested both under laboratory conditions and in clinical settings. The key building blocks of this circuit are low dropout regulators, a DC-DC voltage booster and a single high-power current source OP-Amp with current-limiting capabilities. This allows the device to deliver high-voltage, constant current, biphasic pulses without the use of a bulky step-up transformer. The advantages of the proposed design over the currently existing devices include improved safety features (zero DC current, current-limiting mechanism and safe pulses), waveform morphology that causes less muscle fatigue, cost-effectiveness and compact power-efficient circuit design with minimal components. The device is also capable of producing appropriate ankle dorsiflexion in patients having foot drop problems of various Medical Research Council scale grades.

  20. Effects of Positive Unified Behavior Support on Instruction

    ERIC Educational Resources Information Center

    Scott, John S.; White, Richard; Algozzine, Bob; Algozzine, Kate

    2009-01-01

    "Positive Unified Behavior Support" (PUBS) is a school-wide intervention designed to establish uniform attitudes, expectations, correction procedures, and roles among faculty, staff, and administration. PUBS is grounded in the general principles of positive behavior support and represents a straightforward, practical implementation model. When…

  1. Position Effects in Play Equipment Preferences of Nursery School Children.

    ERIC Educational Resources Information Center

    Witt, Peter A.; Gramza, Anthony F.

    With reference to the need for delineation of parameters operative in children's play, the position preferences of four groups of nursery school subjects were studied in a laboratory playroom. A large and small trestle were interchanged between center and corner positions in a series of play sessions. The frequency with which the subjects used…

  2. Effect of stance position on kick performance in taekwondo.

    PubMed

    Estevan, Isaac; Jandacka, Daniel; Falco, Coral

    2013-01-01

    In taekwondo, the stance position can potentially affect kick performance. The aim of this study was to analyse mechanical variables in the roundhouse kick in taekwondo according to three stance positions (0°, 45°, 90°). Nine experienced taekwondo athletes performed consecutive kicking trials in a random order according to these three relative positions of the feet on the ground. Measurements for the mechanical analysis were performed using two 3D force plates and an eight-camera motion capture system. The taekwondo athletes' reaction and execution times were shorter when starting from the 0° and 45° stance positions than from the 90° position (P < 0.05). Moreover, the ground reaction force was negatively correlated with execution time and positively with velocity of thigh and shank. Our results suggest that the stance position affects the execution technique of taekwondo athletes' kicks. It is suggested that athletes should not adopt the 90° stance position because it will not enable them to achieve the best performance in the roundhouse kick.

  3. Biphasic patterns of diversification and the emergence of modules

    PubMed Central

    Mittenthal, Jay; Caetano-Anollés, Derek; Caetano-Anollés, Gustavo

    2012-01-01

    The intricate molecular and cellular structure of organisms converts energy to work, which builds and maintains structure. Evolving structure implements modules, in which parts are tightly linked. Each module performs characteristic functions. In this work we propose that a module can emerge through two phases of diversification of parts. Early in the first phase of this biphasic pattern, the parts have weak linkage—they interact weakly and associate variously. The parts diversify and compete. Under selection for performance, interactions among the parts increasingly constrain their structure and associations. As many variants are eliminated, parts self-organize into modules with tight linkage. Linkage may increase in response to exogenous stresses as well as endogenous processes. In the second phase of diversification, variants of the module and its functions evolve and become new parts for a new cycle of generation of higher-level modules. This linkage hypothesis can interpret biphasic patterns in the diversification of protein domain structure, RNA and protein shapes, and networks in metabolism, codes, and embryos, and can explain hierarchical levels of structural organization that are widespread in biology. PMID:22891076

  4. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

    PubMed

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-04-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

  5. Biphasic behavior of energy in a stepped chain

    NASA Astrophysics Data System (ADS)

    Ping-Jian, Wang; Ai-Xiang, He; Zhong-Hai, Lin; Guang-Fen, Wei; Yan-Li, Liu

    2016-06-01

    The impact energy decay in a step-up chain containing two sections is numerically studied. There is a marked biphasic behavior of energy decay in the first section. Two sections close to the interface are in compression state. The degree of compression of the first section first decreases and becomes weakest at “crossing” time of biphasic behavior of energy, then increases. The further calculations provide the dependence of the character time on mass ratio (m 1/m 2), where m 1 and m 2 are the particle mass in the first and second section respectively. The bigger the α (α = [(Ωm 1 - m 2)/(Ωm 1 + m 2)]2 with Ω = 1.345), the bigger the energy ratio is. The multipulse structure restricts the transport of energy. Project supported by the National Natural Science Foundation of China (Grant Nos. 61174007 and 61307041) and the Natural Science Foundation of Shandong Province, China (Grant No. ZR2013AL014).

  6. Positive emotions and the social broadening effects of Barack Obama.

    PubMed

    Ong, Anthony D; Burrow, Anthony L; Fuller-Rowell, Thomas E

    2012-10-01

    Past experiments have demonstrated that the cognitive broadening produced by positive emotions may extend to social contexts. Building on this evidence, we hypothesized that positive emotions triggered by thinking about Barack Obama may broaden and expand people's sense of self to include others. Results from an expressive-writing study demonstrated that African American college students prompted to write about Obama immediately prior to and after the 2008 presidential election used more plural self-references, fewer other-references, and more social references. Mediation analyses revealed that writing about Obama increased positive emotions, which in turn increased the likelihood that people thought in terms of more-inclusive superordinate categories (we and us rather than they and them). Implications of these findings for the role of positive emotions in perspective-taking and intergroup relations are considered.

  7. Canopy position has a profound effect on soybean seed composition.

    PubMed

    Huber, Steven C; Li, Kunzhi; Nelson, Randall; Ulanov, Alexander; DeMuro, Catherine M; Baxter, Ivan

    2016-01-01

    Although soybean seeds appear homogeneous, their composition (protein, oil and mineral concentrations) can vary significantly with the canopy position where they were produced. In studies with 10 cultivars grown over a 3-yr period, we found that seeds produced at the top of the canopy have higher concentrations of protein but less oil and lower concentrations of minerals such as Mg, Fe, and Cu compared to seeds produced at the bottom of the canopy. Among cultivars, mean protein concentration (average of different positions) correlated positively with mean concentrations of S, Zn and Fe, but not other minerals. Therefore, on a whole plant basis, the uptake and allocation of S, Zn and Fe to seeds correlated with the production and allocation of reduced N to seed protein; however, the reduced N and correlated minerals (S, Zn and Fe) showed different patterns of allocation among node positions. For example, while mean concentrations of protein and Fe correlated positively, the two parameters correlated negatively in terms of variation with canopy position. Altering the microenvironment within the soybean canopy by removing neighboring plants at flowering increased protein concentration in particular at lower node positions and thus altered the node-position gradient in protein (and oil) without altering the distribution of Mg, Fe and Cu, suggesting different underlying control mechanisms. Metabolomic analysis of developing seeds at different positions in the canopy suggests that availability of free asparagine may be a positive determinant of storage protein accumulation in seeds and may explain the increased protein accumulation in seeds produced at the top of the canopy. Our results establish node-position variation in seed constituents and provide a new experimental system to identify genes controlling key aspects of seed composition. In addition, our results provide an unexpected and simple approach to link agronomic practices to improve human nutrition and health

  8. Canopy position has a profound effect on soybean seed composition

    PubMed Central

    Ulanov, Alexander; DeMuro, Catherine M.

    2016-01-01

    Although soybean seeds appear homogeneous, their composition (protein, oil and mineral concentrations) can vary significantly with the canopy position where they were produced. In studies with 10 cultivars grown over a 3-yr period, we found that seeds produced at the top of the canopy have higher concentrations of protein but less oil and lower concentrations of minerals such as Mg, Fe, and Cu compared to seeds produced at the bottom of the canopy. Among cultivars, mean protein concentration (average of different positions) correlated positively with mean concentrations of S, Zn and Fe, but not other minerals. Therefore, on a whole plant basis, the uptake and allocation of S, Zn and Fe to seeds correlated with the production and allocation of reduced N to seed protein; however, the reduced N and correlated minerals (S, Zn and Fe) showed different patterns of allocation among node positions. For example, while mean concentrations of protein and Fe correlated positively, the two parameters correlated negatively in terms of variation with canopy position. Altering the microenvironment within the soybean canopy by removing neighboring plants at flowering increased protein concentration in particular at lower node positions and thus altered the node-position gradient in protein (and oil) without altering the distribution of Mg, Fe and Cu, suggesting different underlying control mechanisms. Metabolomic analysis of developing seeds at different positions in the canopy suggests that availability of free asparagine may be a positive determinant of storage protein accumulation in seeds and may explain the increased protein accumulation in seeds produced at the top of the canopy. Our results establish node-position variation in seed constituents and provide a new experimental system to identify genes controlling key aspects of seed composition. In addition, our results provide an unexpected and simple approach to link agronomic practices to improve human nutrition and health

  9. Two forms of intergroup discrimination with positive and negative outcomes: explaining the positive-negative asymmetry effect.

    PubMed

    Gardham, K; Brown, R

    2001-03-01

    The minimal group paradigm is widely used for the study of intergroup discrimination. Reliably, group members show in-group favouritism in the allocation of positive outcomes but not in the allocation of negative outcomes. Less frequently investigated has been the withdrawal of positive and negative outcomes in the minimal paradigm. In this minimal group experiment the method of discrimination (allocation vs. withdrawal) and valence of outcomes (positive vs. negative) were combined in a 2 x 2 design (N = 57). Participants showed significant in-group favouritism only in the allocate (+) condition, less in withdrawal (-), and none at all in the remaining two cells (where parity predominated). Measures of subgroup and superordinate category identification paralleled these findings, and their inclusion as covariates in the analyses of favouritism and parity measures eliminated the previously significant interactions, thus implicating recategorization as the process mediating positive-negative asymmetry effects in intergroup discrimination.

  10. An augmented Lagrangian finite element formulation for 3D contact of biphasic tissues.

    PubMed

    Guo, Hongqiang; Spilker, Robert L

    2014-01-01

    Biphasic contact analysis is essential to obtain a complete understanding of soft tissue biomechanics, and the importance of physiological structure on the joint biomechanics has long been recognised; however, up to date, there are no successful developments of biphasic finite element contact analysis for three-dimensional (3D) geometries of physiological joints. The aim of this study was to develop a finite element formulation for biphasic contact of 3D physiological joints. The augmented Lagrangian method was used to enforce the continuity of contact traction and fluid pressure across the contact interface. The biphasic contact method was implemented in the commercial software COMSOL Multiphysics 4.2(®) (COMSOL, Inc., Burlington, MA). The accuracy of the implementation was verified using 3D biphasic contact problems, including indentation with a flat-ended indenter and contact of glenohumeral cartilage layers. The ability of the method to model multibody biphasic contact of physiological joints was proved by a 3D knee model. The 3D biphasic finite element contact method developed in this study can be used to study the biphasic behaviours of the physiological joints.

  11. Effects of student ontological position on cognition of human origins

    NASA Astrophysics Data System (ADS)

    Ervin, Jeremy Alan

    In this study, the narratives from a hermeneutical dialectic cycle of three high school students were analyzed to understand the influences of ontological position on the learning of human origins. The interpretation of the narratives provides the reader an opportunity to consider the learning process from the perspective of worldview and conceptual change theories. Questions guiding this research include: Within a context of a worldview, what is the range of ontological positions among a high school AP biology class? To what extent does ontological position influence the learning of scientific concepts about human origins? If a student's ontological position is contradictory to scientific explanation of human origins, how will learning strategies and motivations change? All consenting students in an AP biology class were interviewed in order to select three students who represented three different ontological positions of a worldview: No Supernatural, Supernatural Without Impact, or Supernatural Impact. The issue of worldview is addressed at length in this work. Consenting students had completed the graduation requirements in biology, but were taking an additional biology course in preparation for college. Enrollment in an AP biology course was assumed to indicate that the selected students have an understanding of the concept of human origins at a comprehensive level, but not necessarily at an apprehension level, both being needed for conceptual change. Examination of the narratives reveals that students may alternate between two ontological positions in order to account for inconsistencies within a situation. This relativity enables the range of ontological positions to vary depending on concepts being considered. Not all Supernatural Impact positions conflict with biological understanding of human origins due to the ability of some to create a dichotomy between religion and school. Any comprehended concepts within this dichotomy lead to plagiaristic knowledge

  12. [Cancer as psychological trauma and its effects on positive illusions].

    PubMed

    Tanyi, Zsuzsanna; Bugán, Antal; Szluha, Kornélia

    2012-01-01

    Cancer as a psychological trauma can result in development of psychopathological disorders (e.g. depression), and also positive changes experienced in numerous domains of life (e.g. greater appreciation of life). Cognitivists tried to explain the potential traumatic impact of the adversities with the phenomenon that most of the people's world concepts are full of positive illusions and they mostly lack the idea that tragedies can occur also with them. However, this naive worldview can be altered by a trauma in a negative way. Moreover, according to the theory of cognitive adaptation certain positive illusions (perception of personal control, self-enhancement, unrealistic optimism, search for meaning) become even more activated by traumatic life events helping the adjustment to the adversity. More recently, researches have succeeded in proving the role of positive illusions in maintaining mental and physical health. The aim of the present study is to review the potential psychological consequences of cancer as a trauma and to display the schema-changes of trauma victims through the phenomenon of positive illusions.

  13. Oscillatory Motion of a Bi-Phasic Slug in a Teflon Reactor

    NASA Astrophysics Data System (ADS)

    Abolhasani, Milad; Jensen, Klavs

    2015-11-01

    Bi-phasic physical/chemical processes require transfer of solute/reagent molecules across the interface. Continuous multi-phase flow approaches (using gas as the continuous phase), usually fail in providing sufficient interfacial area for transfer of molecules between the aqueous and organic phases. In continuous segmented flow platforms (with a fluorinated polymer-based reactor), the higher surface tension of the aqueous phase compared to the organic phase of a bi-phasic slug, in combination with the low surface energy of the reactor wall result in a more facile motion of the aqueous phase. Thus, upon applying a pressure gradient across the bi-phasic slug, the aqueous phase of the slug moves through the organic phase and leads the bi-phasic slug, thereby limiting the available interfacial area for the bi-phasic mass transfer only to the semi-spherical interface between the two phases. Disrupting the quasi-equilibrium state of the bi-phasic slug through reversing the pressure gradient across the bi-phasic slug causes the aqueous phase to move back through the organic phase. In this work, we experimentally investigate the dynamics of periodic alteration of the pressure gradient across a bi-phasic slug, and characterize the resulting enhanced interfacial area on the bi-phasic mass transfer rate. We demonstrate the enhanced mass transfer rate of the oscillatory flow strategy compared to the continuous multi-phase approach using bi-phasic Pd catalyzed carbon-carbon and carbon-nitrogen cross coupling reactions. NSERC Postdoctoral Fellowship, Novartis Center for Continuous Manufacturing.

  14. Biphasic responses of the honeybee heart to nanomolar concentrations of amitraz.

    PubMed

    Papaefthimiou, Chrisovalantis; Papachristoforou, Alexandros; Theophilidis, George

    2013-09-01

    Amitraz is a pesticide targeting the octopaminergic receptors. In a previous study, octopamine, a biogenic amine, was found to induce a biphasic effect on the honeybee heart, inhibition at low concentrations and excitation at high concentrations. Furthermore, the honeybee heart was found to be far more sensitive to octopamine compared to other insect hearts. The objective of the present study was to investigate the effects of amitraz on the electrical and mechanical properties of the honeybee heart ex vivo and on the heart rate in vivo. In ex vivo conditions, amitraz at 10(-12) M caused a significant inhibition in the mechanical (p<0.05, n=4) and electrical properties (p<0.05, n=4). Higher concentrations such as 10(-9) and 10(-6) M induced a biphasic effect, with total inhibition for 7.86±1.26 min (n=7), followed by strong excitation of spontaneously-generated contractions (n=7). The initial elimination of heart activity was caused by strong hyperpolarization, while the subsequent excitation was caused by a depolarization in the membrane potential of pacemaker cells at 10(-9) M (n=8). In the in vivo experiments, abdominal injection or oral application of 0.20 ng of amitraz per bee induced a persistent increase of 134.28±4.07% (p<0.05, n=4) in the frequency of the cardiac action potentials. The above responses clearly show that the heart of the honeybee is extremely vulnerable to amitraz, which is nevertheless still used inside beehives, ostensibly to "protect" the honeybees against their main parasite, Varroa destructor.

  15. Frequent biphasic cellular responses of permanent fish cell cultures to deoxynivalenol (DON)

    SciTech Connect

    Pietsch, Constanze; Bucheli, Thomas D.; Wettstein, Felix E.; Burkhardt-Holm, Patricia

    2011-10-01

    Contamination of animal feed with mycotoxins is a major problem for fish feed mainly due to usage of contaminated ingredients for production and inappropriate storage of feed. The use of cereals for fish food production further increases the risk of a potential contamination. Potential contaminants include the mycotoxin deoxynivalenol (DON) which is synthesized by globally distributed fungi of the genus Fusarium. The toxicity of DON is well recognized in mammals. In this study, we confirm cytotoxic effects of DON in established permanent fish cell lines. We demonstrate that DON is capable of influencing the metabolic activity and cell viability in fish cells as determined by different assays to indicate possible cellular targets of this toxin. Evaluation of cell viability by measurement of membrane integrity, mitochondrial activity and lysosomal function after 24 h of exposure of fish cell lines to DON at a concentration range of 0-3000 ng ml{sup -1} shows a biphasic effect on cells although differences in sensitivity occur. The cell lines derived from rainbow trout are particularly sensitive to DON. The focus of this study lies, furthermore, on the effects of DON at different concentrations on production of reactive oxygen species (ROS) in the different fish cell lines. The results show that DON mainly reduces ROS production in all cell lines that were used. Thus, our comparative investigations reveal that the fish cell lines show distinct species-related endpoint sensitivities that also depend on the type of tissue from which the cells were derived and the severity of exposure. - Highlights: > DON uptake by cells is not extensive. > All fish cell lines are sensitive to DON. > DON is most cytotoxic to rainbow trout cells. > Biphasic cellular responses were frequently observed. > Our results are similar to studies on mammalian cell lines.

  16. Biphasic hormonal responses to the adrenocorticolytic DDT metabolite 3-methylsulfonyl-DDE in human cells

    SciTech Connect

    Asp, Vendela; Ulleras, Erik; Lindstroem, Veronica; Bergstroem, Ulrika; Oskarsson, Agneta; Brandt, Ingvar

    2010-02-01

    The DDT metabolite 3-methylsulfonyl-DDE (3-MeSO{sub 2}-DDE) has been proposed as a lead compound for an improved adrenocortical carcinoma (ACC) treatment. ACC is a rare malignant disorder with poor prognosis, and the current pharmacological therapy o,p'-DDD (mitotane) has limited efficacy and causes severe adverse effects. 3-MeSO{sub 2}-DDE is bioactivated by cytochrome P450 (CYP) 11B1 in mice and causes formation of irreversibly bound protein adducts, reduced glucocorticoid secretion, and cell death in the adrenal cortex of several animal species. The present study was carried out to assess similarities and differences between mice and humans concerning the adrenocorticolytic effects of 3-MeSO{sub 2}-DDE. The results support previous indications that humans are sensitive to the adrenocorticolytic actions of 3-MeSO{sub 2}-DDE by demonstrating protein adduct formation and cytotoxicity in the human adrenocortical cell line H295R. However, neither the irreversible binding nor the cytotoxicity of 3-MeSO{sub 2}-DDE in H295R cells was inhibited by the CYP11B1 inhibitor etomidate. We also report biphasic responses to 3-MeSO{sub 2}-DDE in cortisol and aldosterone secretion as well as in mRNA levels of the steroidogenic genes StAR, CYP11B1 and CYP11B2. Hormone levels and mRNA levels were increased at lower concentrations of 3-MeSO{sub 2}-DDE, while higher concentrations decreased hormone levels. These biphasic responses were not observed with o,p'-DDD or with the precursor DDT metabolite p,p'-DDE. Based on these results, 3-MeSO{sub 2}-DDE remains a viable lead compound for drug design, although the adrenocorticolytic effects of 3-MeSO{sub 2}-DDE in human cells seem more complex than in murine cells.

  17. Effects of Negative and Positive Evidence on Adult Word Learning

    ERIC Educational Resources Information Center

    Strapp, Chehalis M.; Helmick, Augusta L.; Tonkovich, Hayley M.; Bleakney, Dana M.

    2011-01-01

    This study compared negative and positive evidence in adult word learning, predicting that adults would learn more forms following negative evidence. Ninety-two native English speakers (32 men and 60 women [M[subscript age] = 20.38 years, SD = 2.80]), learned nonsense nouns and verbs provided within English frames. Later, participants produced…

  18. Canopy position has a profound effect on soybean seed composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although soybean seeds appear homogenous their composition (protein, oil and mineral concentrations) can vary significantly with canopy position. Seeds produced at the top of the canopy have higher concentrations of protein but less oil and minerals such as Mg, Fe, and Cu compared to seeds produced ...

  19. Working Positively with Sexual Offenders: Maximizing the Effectiveness of Treatment

    ERIC Educational Resources Information Center

    Marshall, William L.; Ward, Tony; Mann, Ruth E.; Moulden, Heather; Fernandez, Yolanda M.; Serran, Geris; Marshall, Liam E.

    2005-01-01

    In this article, the authors draw on literatures outside sexual offending and make suggestions for working more positively and constructively with these offenders. Although the management of risk is a necessary feature of treatment, it needs to occur in conjunction with a strength-based approach. An exclusive focus on risk can lead to overly…

  20. Design, building and test of one prototype and four final position sensor assemblies: Hall effect position sensors

    NASA Technical Reports Server (NTRS)

    1976-01-01

    This report covers the development of a three channel Hall effect position sensing system for the commutation of a three phase dc torquer motor. The effort consisted of the evaluation, modification and re-packaging of a commercial position sensor and the design of a target configuration unique to this application. The resulting design meets the contract requirements and, furthermore, the test results indicate not only the practicality and versatility of the design, but also that there may be higher limits of resolution and accuracy achievable.

  1. Light controlled reversible inversion of nanophosphor-stabilized Pickering emulsions for biphasic enantioselective biocatalysis.

    PubMed

    Chen, Zhaowei; Zhou, Li; Bing, Wei; Zhang, Zhijun; Li, Zhenhua; Ren, Jinsong; Qu, Xiaogang

    2014-05-21

    In this work, by utilizing photochromic spiropyrans conjugated upconversion nanophosphors, we have successfully prepared NIR/visible light tuned interfacially active nanoparticles for the formulation of Pickering emulsions with reversible inversion properties. By loading a model enantioselective biocatalytic active bacteria Alcaligenes faecalis ATCC 8750 in the aqueous phase, we demonstrated for the first time that the multifunctional Pickering emulsion not only highly enhanced its catalytic performance but also relieved the substrate inhibition effect. In addition, product recovery, and biocatalysts and colloid emulsifiers recycling could be easily realized based on the inversion ability of the Pickering emulsion. Most importantly, the utilization of NIR/visible light to perform the reversible inversion without any chemical auxiliaries or temperature variation showed little damage toward the biocatalysts, which was highlighted by the high catalytic efficiency and high enantioselectivity even after 10 cycles. The NIR/visible light controlled Pickering emulsion showed promising potential as a powerful technique for biocatalysis in biphasic systems.

  2. Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions.

    SciTech Connect

    Chaiko, D. J.; Hatton, T. A.; Zaslavsky, B.

    1999-05-03

    Certain radionuclide ions (e.g., TcO{sub 4}{sup 16}) exhibit unusually strong Affinities toward the polymer-rich phase in aqueous biphase systems generated by combinations of salt solutions with polymers such as poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Thus, aqueous polymer phases could potentially be used to selectively extract these ions during pretreatment of radioactive tank wastes at Hanford. To help develop a fundamental understanding of the interactions between various ions and polymers in aqueous solution, interaction enthalpies between sodium perrhenate and a random copolymer of PEG and PPG (UCON-50) were measured by microcalorimetric titration. An entropy compensation effect was observed in this system in which changes in enthalpic interactions were balanced by entropy changes such that the interaction free energy remained constant and approximately equal to zero.

  3. A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

    PubMed Central

    Smeets, Ralf; Kolk, Andreas; Gerressen, Marcus; Driemel, Oliver; Maciejewski, Oliver; Hermanns-Sachweh, Benita; Riediger, Dieter; Stein, Jamal M

    2009-01-01

    The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC) with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential) which was found to be favorable for bone regeneration and osseointegration of dental implants. PMID:19523239

  4. Regulation of the Demographic Structure in Isomorphic Biphasic Life Cycles at the Spatial Fine Scale

    PubMed Central

    Vieira, Vasco Manuel Nobre de Carvalho da Silva; Mateus, Marcos Duarte

    2014-01-01

    Isomorphic biphasic algal life cycles often occur in the environment at ploidy abundance ratios (Haploid:Diploid) different from 1. Its spatial variability occurs within populations related to intertidal height and hydrodynamic stress, possibly reflecting the niche partitioning driven by their diverging adaptation to the environment argued necessary for their prevalence (evolutionary stability). Demographic models based in matrix algebra were developed to investigate which vital rates may efficiently generate an H:D variability at a fine spatial resolution. It was also taken into account time variation and type of life strategy. Ploidy dissimilarities in fecundity rates set an H:D spatial structure miss-fitting the ploidy fitness ratio. The same happened with ploidy dissimilarities in ramet growth whenever reproductive output dominated the population demography. Only through ploidy dissimilarities in looping rates (stasis, breakage and clonal growth) did the life cycle respond to a spatially heterogeneous environment efficiently creating a niche partition. Marginal locations were more sensitive than central locations. Related results have been obtained experimentally and numerically for widely different life cycles from the plant and animal kingdoms. Spore dispersal smoothed the effects of ploidy dissimilarities in fertility and enhanced the effects of ploidy dissimilarities looping rates. Ploidy dissimilarities in spore dispersal could also create the necessary niche partition, both over the space and time dimensions, even in spatial homogeneous environments and without the need for conditional differentiation of the ramets. Fine scale spatial variability may be the key for the prevalence of isomorphic biphasic life cycles, which has been neglected so far. PMID:24658603

  5. Biphasic cultivation strategy to avoid Epo-Fc aggregation and optimize protein expression.

    PubMed

    Kaisermayer, Christian; Reinhart, David; Gili, Andreas; Chang, Martina; Aberg, Per-Mikael; Castan, Andreas; Kunert, Renate

    2016-06-10

    In biphasic cultivations, the culture conditions are initially kept at an optimum for rapid cell growth and biomass accumulation. In the second phase, the culture is shifted to conditions ensuring maximum specific protein production and the protein quality required. The influence of specific culture parameters is cell line dependent and their impact on product quality needs to be investigated. In this study, a biphasic cultivation strategy for a Chinese hamster ovary (CHO) cell line expressing an erythropoietin fusion protein (Epo-Fc) was developed. Cultures were run in batch mode and after an initial growth phase, cultivation temperature and pH were shifted. Applying a DoE (Design of Experiments) approach, a fractional factorial design was used to systematically evaluate the influence of cultivation temperature and pH as well as their synergistic effect on cell growth as well as on recombinant protein production and aggregation. All three responses were influenced by the cultivation temperature. Additionally, an interaction between pH and temperature was found to be related to protein aggregation. Compared with the initial standard conditions of 37°C and pH 7.05, a parameter shift to low temperature and acidic pH resulted in a decrease in the aggregate fraction from 75% to less than 1%. Furthermore, the synergistic effect of temperature and pH substantially lowered the cell-specific rates of glucose and glutamine consumption as well as lactate and ammonium production. The optimized culture conditions also led to an increase of the cell-specific rates of recombinant Epo-Fc production, thus resulting in a more economic bioprocess.

  6. Effect of body position on feline electrocardiographic recordings.

    PubMed

    Harvey, A M; Faena, M; Darke, P G G; Ferasin, L

    2005-01-01

    The aim of this study was to determine whether changes in body position alter feline electrocardiographic parameters. Forty-seven cats referred to the Feline Unit of the University of Bristol had electrocardiograms (ECGs) recorded. Only cats presenting in sinus rhythm were included in the study (n = 41). ECGs were recorded either as part of the investigation for potential cardiac disease (n = 38) or as a preanesthetic screen (n = 3). Standard 6-lead ECGs (leads I, II, III, aVR, aVL, and aVF) were recorded in 3 different recumbent positions in the 41 cats. Recordings were 1st made in right lateral (RL) recumbency, followed by sternal (ST) and then left lateral (LL) recumbency. Measurements were taken of the amplitude and duration of P waves and QRS complexes and duration of PQ and QT intervals from lead II was taken in the 3 different positions. Mean electrical axis (MEA) also was calculated. Repeated measures analysis of variance was performed and identified a significant difference in R wave amplitudes (P = .009) and MEA (P = .037) among the 3 different body positions. Two-tailed paired t-tests demonstrated that the R wave amplitude differed significantly both in ST (P = .025) and LL recumbency (P = .009). The mean R wave amplitude was reduced in both ST and LL recumbency when compared with RL recumbency. The MEA only was significantly different in LL recumbency (P = .037). ST and LL recumbencies should not be used for recording ECGs in cats if amplitudes and MEA are to be compared with standard references.

  7. Copper: a biphasic regulator of caprine sperm forward progression.

    PubMed

    Roy, Debarun; Dey, Souvik; Majumder, Gopal Chandra; Bhattacharyya, Debdas

    2014-02-01

    Copper is essential for spermatogenesis and its presence has been demonstrated in male and female reproductive fluids in several mammalian species. However, little is known about the physiological significance of this trace element in the regulation of forward progression of mammalian sperm cells which is essential for sperm fertility potential in vivo. The purpose of this investigation was to determine the physiological role of the bivalent copper ion (Cu(2+)) on mammalian sperm forward motility using a chemically-defined medium and caprine cauda epididymal sperm model. Sperm forward motility was significantly enhanced by Cu(2+) in a dose-dependent manner; maximal activation (approx 20%) was noted at the 5 µM level of the metal. Above 10 µM Cu(2+) sperm motility decreased, showing that Cu(2+) exerts a biphasic regulation on sperm motility. These findings have been confirmed using a spectrophotometric motility assay, an objective method of motility analysis. At lower concentrations (up to 5 µM), copper enhanced sperm membrane lipid peroxidation as well as the level of intra-sperm cyclic adenosine mono phosphate (c-AMP), but at a higher level it caused marked inhibition of both of the biochemical parameters. The observed correlation of Cu(2+)-dependent biphasic modulation of sperm membrane lipid peroxidation and intrasperm c-AMP with sperm forward motility is consistent with the view that Cu(2+) regulation of sperm motility is mediated by membrane lipid peroxidation, which in turn modulates the level of intra-sperm c-AMP, a well-known activator of sperm motility.

  8. Effective Teaching Practices that Promote a Positive Classroom Environment

    ERIC Educational Resources Information Center

    MacSuga-Gage, Ashley S.; Simonsen, Brandi; Briere, Donald E.

    2012-01-01

    Establishing effective academic instruction, effective classroom management, and building relationships can all be accomplished with the application of observable and measurable practices. How an individual applies these practices will vary, yet common components of effective teaching are omnipresent. Across academic instruction, behavior…

  9. Influence of surface porosity and pH on bacterial adherence to hydroxyapatite and biphasic calcium phosphate bioceramics.

    PubMed

    Kinnari, Teemu J; Esteban, Jaime; Martin-de-Hijas, Nieves Z; Sánchez-Muñoz, Orlando; Sánchez-Salcedo, Sandra; Colilla, Montserrat; Vallet-Regí, María; Gomez-Barrena, Enrique

    2009-01-01

    Hydroxyapatite (HA) and biphasic calcium phosphate (BCP) ceramic materials are widely employed as bone substitutes due to their porous and osteoconductive structure. Their porosity and the lowering of surrounding pH as a result of surgical trauma may, however, predispose these materials to bacterial infections. For this reason, the influence of porosity and pH on the adherence of common Gram-positive bacteria to the surfaces of these materials requires investigation. Mercury intrusion porosimetry measurements revealed that the pore size distribution of both bioceramics had, on a logarithmic scale, a sinusoidal frequency distribution ranging from 50 to 300 nm, with a mean pore diameter of 200 nm. Moreover, total porosity was 20 % for HA and 50 % for BCP. Adherence of Staphylococcus aureus and Staphylococcus epidermidis was studied at a physiological pH of 7.4 and at a pH simulating bone infection of 6.8. Moreover, the effect of pH on the zeta potential of HA, BCP and of both staphylococci was evaluated. Results showed that when pH decreased from 7.4 to 6.8, the adherence of both staphylococci to HA and BCP surfaces decreased significantly, although at the same time the negative zeta-potential values of the ceramic surfaces and both bacteria diminished. At both pH values, the number of S. aureus adhered to the HA surface appeared to be lower than that for BCP. A decrease in pH to 6.8 reduced the adherence of both bacterial species (mean 57 %). This study provides evidence that HA and BCP ceramics do not have pores sufficiently large to allow the internalization of staphylococci. Their anti-adherent properties seemed to improve when pH value decreased, suggesting that HA and BCP bioceramics are not compromised upon orthopaedic use.

  10. Effects of positive and negative delusional ideation on memory.

    PubMed

    Sugimori, Eriko; Tanno, Yoshihiko

    2010-04-01

    We investigated the relationship between levels of delusional ideation (whether positive or negative delusions) and the activation and distortion of memory by using pairs of positive and negative adjectives describing personality traits where those adjectives had similar meanings. We presented one of each pair of adjectives in the learning phase. Immediately after the learning phase in Experiment 1, we asked whether each adjective had been presented. Participants with high (positive or negative) delusional ideation were more likely to indicate that they had learned adjectives that they had not actually learned. This finding suggested that non-learned positive (or negative) adjectives that were associated with learned negative (or positive) adjectives were more likely to be activated in participants prone to positive (or negative) delusional ideation. However, in Experiment 2, two forced-choice tests were conducted immediately after the learning phase. In this context, participants, regardless of their proneness to delusional ideation, could almost always correctly distinguish what had and had not been presented, suggesting that the activation of learned items was still stronger than that for non-learned items in the immediate test. As time passed, the proportion of false alarms for positive or negative adjectives was higher in the two forced-choice tests among those with high proneness to (positive or negative) delusional ideation, suggesting that participants with delusional ideation were increasingly likely to depend on internal conditions for retrieval over time. Nous avons examiné la relation entre les niveaux d'idéation illusoire (qu'elle soit positive ou négative) et l'activation et la distorsion de la mémoire, en utilisant des paires d'adjectifs positifs et négatifs à significations similaires décrivant des traits de personnalité. Nous avons présenté un membre de chaque paire d'adjectifs lors d'une phase d'apprentissage. Dans une première exp

  11. Multipath effects in a Global Positioning Satellite system receiver

    NASA Technical Reports Server (NTRS)

    Mcdonald, Malcolm W.

    1992-01-01

    This study, as a part of a large continuing investigation being conducted by the Communications Systems Branch of the Information and Electronic Systems Laboratory at the Marshall Space Flight Center, was undertaken to explore the multipath response characteristics of a particular Global Positioning Satellite (GPS) receiver which was available in the laboratory at the beginning and throughout the entirety of the study, and to develop a suitable regime of experimental procedure which can be applied to other state-of-the-art GPS receivers in the larger investigation.

  12. Effect of sound similarity and word position on lexical selection

    PubMed Central

    Reilly, Megan; Blumstein, Sheila E.

    2014-01-01

    Spoken word production research has shown that phonological information influences lexical selection. It remains unclear, however, whether this phonological information is specified for its phonological environment (e.g., word position) or its phonetic (allophonic) realization. To examine this, two definition naming experiments were performed during which subjects produced lexical targets (e.g., “balcony”) in response to the targets’ definitions (“deck higher than a building’s first floor”) after naming a series of phonologically related or unrelated primes. Subjects produced target responses significantly more often when the primes were phonologically related to the target, regardless of whether the phonologically related primes matched the target’s word position or did not. For example, subjects were equally primed to produce the target “balcony” after the prime “ballast” or “unbalanced” relative to unrelated primes. Moreover, equal priming occurred irrespective of phonological environment or phonetic realization. The results support models of spoken word production which include context-independent phonological representations. PMID:25436217

  13. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    SciTech Connect

    S.S. KURENNOY

    2001-06-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  14. Effects of positive impression management on the Psychopathic Personality Inventory.

    PubMed

    Edens, J F; Buffington, J K; Tomicic, T L; Riley, B D

    2001-06-01

    The Psychopathic Personality Inventory (PPI; S. O. Lilienfeld & B. P. Andrews, 1996) is a self-report test that has shown considerable promise as a screening measure for psychopathy. A current limitation of the PPI is that no data exist regarding the impact of response sets such as positive impression management. Although the PPI contains a validity scale (Unlikely Virtues) designed to identify response biases such as "faking good," its utility has not yet been assessed. In this study a repeated measures analogue design was employed in which 186 respondents completed the PPI both under standard conditions and with specific instructions to create a favorable impression of themselves. In the "fake good" condition, participants were able to appear significantly less psychopathic, with those who obtained higher scores in the standard instruction condition showing the largest decreases in their PPI scores. Receiver Operating Characteristic analyses indicated that, although the Unlikely Virtues scale significantly differentiated between "fake good" and honest protocols (area under the curve = .73), a considerable number of misclassifications occurred. The clinical and forensic implications of these findings are discussed.

  15. Positive and Negative Recency Effects in Retirement Savings Decisions

    ERIC Educational Resources Information Center

    Rieskamp, Jorg

    2006-01-01

    Retirement savings decisions can be influenced by the fund composition of the retirement savings plan. In 2 experiments, strong composition effects were observed, with a larger percentage of resources being invested in stock funds when more stock than bond funds were offered. Although participants changed their allocations repeatedly, the…

  16. Positioning for Effectiveness: Applying Marketing Concepts to Distance Education.

    ERIC Educational Resources Information Center

    Levenburg, Nancy

    1997-01-01

    Demonstrates how colleges can use distance education to attract and retain a "critical mass" of learners for distance programs. Explores alternative ways to view distance education market opportunities and determine which avenues to pursue. Suggests how to be more effective in all aspects of distance education programs. (13 citations) (YKH)

  17. Modeling Item-Position Effects within an IRT Framework

    ERIC Educational Resources Information Center

    Debeer, Dries; Janssen, Rianne

    2013-01-01

    Changing the order of items between alternate test forms to prevent copying and to enhance test security is a common practice in achievement testing. However, these changes in item order may affect item and test characteristics. Several procedures have been proposed for studying these item-order effects. The present study explores the use of…

  18. Carbon dioxide stimulates the production of amylovorin L by Lactobacillus amylovorus DCE 471, while enhanced aeration causes biphasic kinetics of growth and bacteriocin production.

    PubMed

    Neysens, Patricia; De Vuyst, Luc

    2005-11-25

    The effects of both oxygen and carbon dioxide on growth of and product formation by Lactobacillus amylovorus DCE 471, a promising new sourdough starter culture, were assessed through controlled, in vitro fermentation experiments, using a temperature of 37 degrees C and a constant pH of 5.4. It was seen that aeration affected both cell growth and amylovorin L production. At aeration rates of 1 l min(-1) and more, the bacterial population was subjected to oxidative stress as reflected by biphasic growth patterns. During the first growth phase, the maximum specific growth rate increased with increasing aeration rates stabilizing at the highest oxygen concentrations. The maximum obtainable cell yields decreased. During the second growth phase, the amylovorin L production was stimulated at the highest aeration. However, amylovorin titers were never higher in the presence of oxygen compared with the anaerobic fermentations. Carbon dioxide did not influence cell growth of L. amylovorus DCE 471. The maximum specific growth rate and the biomass concentrations were merely affected. On the other hand, the maximum soluble bacteriocin titers coincided with the highest carbon dioxide flow rates. These results indicate that mild aeration of type II sourdoughs might enhance both cell yield and amylovorin L production by L. amylovorus DCE 471, thereby contributing to the competitiveness of the strain. Growth in an ecosystem together with yeasts producing carbon dioxide might exert a positive effect on the production of amylovorin L as well.

  19. Effectiveness of infliximab in refractory FDG PET-positive sarcoidosis.

    PubMed

    Vorselaars, Adriane D M; Crommelin, Heleen A; Deneer, Vera H M; Meek, Bob; Claessen, Anke M E; Keijsers, Ruth G M; van Moorsel, Coline H M; Grutters, Jan C

    2015-07-01

    Inconclusive evidence for the efficacy of infliximab in sarcoidosis hinders the global use of this potentially beneficial drug. To study infliximab efficacy in a clinical setting, we performed a prospective open-label trial in patients refractory to conventional treatment. Patients (n=56) received eight infusions of 5 mg·kg(-1) infliximab. Pulmonary function, disease activity measured by (18)F-fluorodeoxyglucose (FDG) by positron emission tomography (PET) and quality of life were part of the clinical work-up. Infliximab levels were measured before every infusion. After 26 weeks of infliximab treatment, mean improvement in forced vital capacity (FVC) was 6.6% predicted (p=0.0007), whereas in the 6 months before start of treatment, lung function decreased. Maximum standardised uptake value (SUVmax) of pulmonary parenchyma on (18)F-FDG PET decreased by 3.93 (p<0.0001). High SUVmax of pulmonary parenchyma at baseline predicted FVC improvement (R=0.62, p=0.0004). An overall beneficial response was seen in 79% of patients and a partial response was seen in 17% of patients. No correlation between infliximab trough level (mean 18.0 µg·mL(-1)) and initial response was found. In conclusion, infliximab causes significant improvement in FVC in refractory (18)F-FDG PET positive sarcoidosis. Especially in pulmonary disease, high (18)F-FDG PET SUVmax values at treatment initiation predict clinically relevant lung function improvement. These results suggest that inclusion of (18)F-FDG PET is useful in therapeutic decision-making in complex sarcoidosis.

  20. Progressive and biphasic cardiac responses during extreme mountain ultramarathon.

    PubMed

    Maufrais, Claire; Millet, Grégoire P; Schuster, Iris; Rupp, Thomas; Nottin, Stéphane

    2016-05-15

    Investigations on the cardiac function consequences of mountain ultramarathon (MUM) >100 h are lacking. The present study assessed the progressive cardiac responses during the world's most challenging MUM (Tor des Géants; Italy; 330 km; 24,000 m of cumulative elevation gain). Resting echocardiographic evaluation of morphology, function, and mechanics of left and right ventricle (LV and RV) including speckle tracking echocardiography was conducted in 15 male participants (46 ± 13 yr) before (pre), during (mid; 148 km), and after (post) the race. Runners completed the race in 126 ± 15 h. From pre to post, the increase in stroke volume (SV) (103 ± 19 vs. 110 ± 23 vs. 116 ± 21 ml; P < 0.001 at pre, mid, and post) was concomitant to the increase in LV early filling (peak E; 72.9 ± 15.7 vs. 74.6 ± 13.1 vs. 82.1 ± 11.5 cm/s; P < 0.05). Left and right atrial end-diastolic areas, RV end-diastolic area, and LV end-diastolic volume were 12-19% higher at post compared with pre (P < 0.05). Resting heart rate and LV systolic strain rates demonstrated a biphasic adaptation with an increase from pre to mid (55 ± 8 vs. 72 ± 11 beats/min, P < 0.001) and a return to baseline values from mid to post (59 ± 8 beats/min). Significant correlations were found between pre-to-post percent changes in peak E and LV end-diastolic volume (r = 0.63, P < 0.05) or RV (r = 0.82, P < 0.001) or atrial end-diastolic areas (r = 0.83, P < 0.001). An extreme MUM induced a biphasic pattern of heart rate in parallel with specific cardiac responses characterized by a progressive increase in diastolic filling, biventricular volumes, and SV. The underlying mechanisms and their clinical implications remain challenging for the future.

  1. Aqueous biphasic plutonium oxide extraction process with pH and particle control

    DOEpatents

    Chaiko, D.J.; Mensah-Biney, R.

    1997-04-29

    A method is described for simultaneously partitioning a metal oxide and silica from a material containing silica and the metal oxide, using a biphasic aqueous medium having immiscible salt and polymer phases. 2 figs.

  2. Exercise Modifies the Gut Microbiota with Positive Health Effects

    PubMed Central

    Monda, Vincenzo; Villano, Ines; Messina, Antonietta; Valenzano, Anna; Esposito, Teresa; Moscatelli, Fiorenzo; Viggiano, Andrea; Cibelli, Giuseppe; Chieffi, Sergio; Monda, Marcellino

    2017-01-01

    The human gastrointestinal tract (GIT) is inhabited by a wide cluster of microorganisms that play protective, structural, and metabolic functions for the intestinal mucosa. Gut microbiota is involved in the barrier functions and in the maintenance of its homeostasis. It provides nutrients, participates in the signaling network, regulates the epithelial development, and affects the immune system. Considering the microbiota ability to respond to homeostatic and physiological changes, some researchers proposed that it can be seen as an endocrine organ. Evidence suggests that different factors can determine changes in the gut microbiota. These changes can be both quantitative and qualitative resulting in variations of the composition and metabolic activity of the gut microbiota which, in turn, can affect health and different disease processes. Recent studies suggest that exercise can enhance the number of beneficial microbial species, enrich the microflora diversity, and improve the development of commensal bacteria. All these effects are beneficial for the host, improving its health status. In this paper, we intend to shed some light over the recent knowledge of the role played by exercise as an environmental factor in determining changes in microbial composition and how these effects could provide benefits to health and disease prevention. PMID:28357027

  3. Exercise Modifies the Gut Microbiota with Positive Health Effects.

    PubMed

    Monda, Vincenzo; Villano, Ines; Messina, Antonietta; Valenzano, Anna; Esposito, Teresa; Moscatelli, Fiorenzo; Viggiano, Andrea; Cibelli, Giuseppe; Chieffi, Sergio; Monda, Marcellino; Messina, Giovanni

    2017-01-01

    The human gastrointestinal tract (GIT) is inhabited by a wide cluster of microorganisms that play protective, structural, and metabolic functions for the intestinal mucosa. Gut microbiota is involved in the barrier functions and in the maintenance of its homeostasis. It provides nutrients, participates in the signaling network, regulates the epithelial development, and affects the immune system. Considering the microbiota ability to respond to homeostatic and physiological changes, some researchers proposed that it can be seen as an endocrine organ. Evidence suggests that different factors can determine changes in the gut microbiota. These changes can be both quantitative and qualitative resulting in variations of the composition and metabolic activity of the gut microbiota which, in turn, can affect health and different disease processes. Recent studies suggest that exercise can enhance the number of beneficial microbial species, enrich the microflora diversity, and improve the development of commensal bacteria. All these effects are beneficial for the host, improving its health status. In this paper, we intend to shed some light over the recent knowledge of the role played by exercise as an environmental factor in determining changes in microbial composition and how these effects could provide benefits to health and disease prevention.

  4. [Positive effects of wheat bran for digestive health; scientific evidence].

    PubMed

    Ruiz-Roso Calvo de Mora, Baltasar

    2015-07-18

    Wheat bran (ST) is very rich in insoluble fiber, consisting mainly arabinoxylans and, to a lesser extent, cellulose and β-glucans, as well as vitamins, minerals and antioxidants polyphenolic. The ST is involved in the regulation of gastrointestinal physiology and health: delayed gastric emptying and intestinal transit speeds and increases fecal bulk. The ST has an effect on faecal bulking greater than other grains such as oats or vegetables and fruits. However, phytic acid present in the bran may reduce the absorption of certain minerals (Ca, Mg, Fe and Zn), due to formation phytate-mineral complexes. Different studies have shown that consumption of bran has protective effect against different diseases: cardiovascular, obesity and some gastrointestinal diseases, including constipation, diverticular disease and colorectal cancer, among others. In Spain the consumption of fiber (18 g/day on average) is below the recommended (30 g/day), so the increased consumption of foods with wheat bran help achieve this recommendation and reduce the incidence of diseases associated a low intake of fiber.

  5. Evaluating the Separate and Combined Effects of Positive and Negative Reinforcement on Task Compliance

    ERIC Educational Resources Information Center

    Bouxsein, Kelly J.; Roane, Henry S.; Harper, Tara

    2011-01-01

    Positive and negative reinforcement are effective for treating escape-maintained destructive behavior. The current study evaluated the separate and combined effects of these contingencies to increase task compliance. Results showed that a combination of positive and negative reinforcement was most effective for increasing compliance. (Contains 1…

  6. Evaluating the separate and combined effects of positive and negative reinforcement on task compliance.

    PubMed

    Bouxsein, Kelly J; Roane, Henry S; Harper, Tara

    2011-01-01

    Positive and negative reinforcement are effective for treating escape-maintained destructive behavior. The current study evaluated the separate and combined effects of these contingencies to increase task compliance. Results showed that a combination of positive and negative reinforcement was most effective for increasing compliance.

  7. Positive effects of duckweed polycultures on starch and protein accumulation.

    PubMed

    Li, Yang; Zhang, Fantao; Daroch, Maurycy; Tang, Jie

    2016-10-01

    The effect of duckweed species composition (Lemna aequinoctialis 5505, Landoltia punctata 5506 and Spirodela polyrhiza 5507) in polyculture and monoculture on biomass and starch/protein content were investigated at different levels of temperature, light intensity, nitrogen and phosphorus concentrations. The three growth parameters significantly affect duckweed biomass accumulation. Different combinations of duckweed species greatly varied in starch/protein content. Although all the polycultures showed a median relative growth rate and the majority of the polycultures showed a median and starch/protein content as compared with their respective monocultures, some of the polycultures were found to promote the accumulation of starch/protein at different growth conditions. These findings indicated that proper combination of duckweed species could facilitate desirable biomass accumulation and improve biomass quality. The present study provides useful references for future large-scale duckweed cultivation.

  8. [Pyoderma gangrenosum--positive effect of cyclosporin A therapy ].

    PubMed

    Krauze, Ewa; Lis, Anna; Kamińska-Budzińska, Grazyna; Wygledowska-Kania, Mariola; Pierzchała, Ewa; Brzezińska-Wcisło, Ligia

    2002-10-01

    Although pyoderma gangrenosum is a disorder known since over 70 years, it still remains a diagnostic and therapeutic problem. We describe three subjects with pyoderma gangrenosum; two were females, one was male, one case was associated with colitis ulcerosa, two were without any related disorders. Histopathologic examinations supported the diagnosis in all cases. In spite of intensive topical and systemic treatment with corticosteroids, Dapsone, Clofazimine, no sufficient effects were achieved. Cyclosporin A introduced in the dose of 5 mg/kg/d resulted in dramatic response and complete remission. Serum CyA levels, biochemical parameters of liver and kidney function, blood pressure were monitored during the therapy. No adverse events due to Cyclosporin A were observed.

  9. Positive effects of duckweed polycultures on starch and protein accumulation

    PubMed Central

    Li, Yang; Zhang, Fantao; Daroch, Maurycy; Tang, Jie

    2016-01-01

    The effect of duckweed species composition (Lemna aequinoctialis 5505, Landoltia punctata 5506 and Spirodela polyrhiza 5507) in polyculture and monoculture on biomass and starch/protein content were investigated at different levels of temperature, light intensity, nitrogen and phosphorus concentrations. The three growth parameters significantly affect duckweed biomass accumulation. Different combinations of duckweed species greatly varied in starch/protein content. Although all the polycultures showed a median relative growth rate and the majority of the polycultures showed a median and starch/protein content as compared with their respective monocultures, some of the polycultures were found to promote the accumulation of starch/protein at different growth conditions. These findings indicated that proper combination of duckweed species could facilitate desirable biomass accumulation and improve biomass quality. The present study provides useful references for future large-scale duckweed cultivation. PMID:27515418

  10. Micrometer-scale mixing with Pickering emulsions: biphasic reactions without stirring.

    PubMed

    Zhang, Wenjuan; Fu, Luman; Yang, Hengquan

    2014-02-01

    A general strategy that avoids stirring for organic/aqueous reactions involving solid catalysts is reported. The strategy involves converting a conventional biphasic system into a Pickering emulsion phase with micrometer-scale droplets ensuring good mixing. In test reactions, nitrotoluene reduction and epoxidation of allylic alcohols, the reaction efficiency is comparable to conventional stirrer-driven biphasic catalysis reaction systems. Short diffusion distances, arising from the compartmentalization of densely packed droplets, play an important role in boosting the reaction efficiency.

  11. Neutron Polarization Analysis for Biphasic Solvent Extraction Systems

    SciTech Connect

    Motokawa, Ryuhei; Endo, Hitoshi; Nagao, Michihiro; Heller, William T.

    2016-06-16

    Here we performed neutron polarization analysis (NPA) of extracted organic phases containing complexes, comprised of Zr(NO3)4 and tri-n-butyl phosphate, which enabled decomposition of the intensity distribution of small-angle neutron scattering (SANS) into the coherent and incoherent scattering components. The coherent scattering intensity, containing structural information, and the incoherent scattering compete over a wide range of magnitude of scattering vector, q, specifically when q is larger than q* ≈ 1/Rg, where Rg is the radius of gyration of scatterer. Therefore, it is important to determine the incoherent scattering intensity exactly to perform an accurate structural analysis from SANS data when Rg is small, such as the aforementioned extracted coordination species. Although NPA is the best method for evaluating the incoherent scattering component for accurately determining the coherent scattering in SANS, this method is not used frequently in SANS data analysis because it is technically challenging. In this study, we successfully demonstrated that experimental determination of the incoherent scattering using NPA is suitable for sample systems containing a small scatterer with a weak coherent scattering intensity, such as extracted complexes in biphasic solvent extraction systems.

  12. Nucleic Acid Sample Preparation using Spontaneous Biphasic Plug Flow

    PubMed Central

    Thomas, Peter C.; Strotman, Lindsay N.; Theberge, Ashleigh B.; Berthier, Erwin; O’Connell, Rachel; Loeb, Jennifer M.; Berry, Scott M.; Beebe, David J.

    2013-01-01

    Nucleic acid (NA) extraction and purification has become a common technique in both research and clinical laboratories. Current methods require repetitive wash steps with a pipette that is laborious and time consuming making it inefficient for clinical settings. We present here a simple technique that relies on spontaneous biphasic plug flow inside a capillary to achieve sample preparation. By filling the sample with oil, aqueous contaminants were displaced from the captured NA without pipetting wash buffers or use of external force and equipment. mRNA from mammalian cell culture was purified and PCR amplification showed similar threshold cycle values as those obtained from a commercially available kit. HIV viral like particles were spiked into serum and a 5-fold increase in viral RNA extraction yield was achieved compared to the conventional wash method. In addition, viral RNA was successfully purified from human whole blood, and a limit of detection of approximately 14 copies of RNA extracted per sample. The results demonstrate the utility of the current technique for nucleic acid purification for clinical purposes, and the overall approach provides a potential method to implement nucleic acid testing in low resource settings. PMID:23941230

  13. Nucleic acid sample preparation using spontaneous biphasic plug flow.

    PubMed

    Thomas, Peter C; Strotman, Lindsay N; Theberge, Ashleigh B; Berthier, Erwin; O'Connell, Rachel; Loeb, Jennifer M; Berry, Scott M; Beebe, David J

    2013-09-17

    Nucleic acid (NA) extraction and purification has become a common technique in both research and clinical laboratories. Current methods require repetitive wash steps with a pipet that are laborious and time-consuming, making the procedure inefficient for clinical settings. We present here a simple technique that relies on spontaneous biphasic plug flow inside a capillary to achieve sample preparation. By filling the sample with oil, aqueous contaminants were displaced from the captured NA without pipetting wash buffers or use of external force and equipment. mRNA from mammalian cell culture was purified, and polymerase chain reaction (PCR) amplification showed similar threshold cycle values as those obtained from a commercially available kit. Human immunodeficiency virus (HIV) viral-like particles were spiked into serum and a 5-fold increase in viral RNA extraction yield was achieved compared to the conventional wash method. In addition, viral RNA was successfully purified from human whole blood, and a limit of detection of approximately 14 copies of RNA extracted per sample was determined. The results demonstrate the utility of the current technique for nucleic acid purification for clinical purposes, and the overall approach provides a potential method to implement nucleic acid testing in low-resource settings.

  14. Osteochondral tissue engineering with biphasic scaffold: current strategies and techniques.

    PubMed

    Shimomura, Kazunori; Moriguchi, Yu; Murawski, Christopher D; Yoshikawa, Hideki; Nakamura, Norimasa

    2014-10-01

    The management of osteoarthritis (OA) remains challenging and controversial. Although several clinical options exist for the treatment of OA, regeneration of the damaged articular cartilage has proved difficult due to the limited healing capacity. With the advancements in tissue engineering and cell-based technologies over the past decade, new therapeutic options for patients with osteochondral lesions potentially exist. This review will focus on the feasibility of tissue-engineered biphasic scaffolds, which can mimic the native osteochondral complex, for osteochondral repair and highlight the recent development of these techniques toward tissue regeneration. Moreover, basic anatomy, strategy for osteochondral repair, the design and fabrication methods of scaffolds, as well as the choice of cells, growth factor, and materials will be discussed. Specifically, we focus on the latest preclinical animal studies using large animals and clinical trials with high clinical relevance. In turn, this will facilitate an understanding of the latest trends in osteochondral repair and contribute to the future application of such clinical therapies in patients with OA.

  15. Neutron Polarization Analysis for Biphasic Solvent Extraction Systems

    DOE PAGES

    Motokawa, Ryuhei; Endo, Hitoshi; Nagao, Michihiro; ...

    2016-06-16

    Here we performed neutron polarization analysis (NPA) of extracted organic phases containing complexes, comprised of Zr(NO3)4 and tri-n-butyl phosphate, which enabled decomposition of the intensity distribution of small-angle neutron scattering (SANS) into the coherent and incoherent scattering components. The coherent scattering intensity, containing structural information, and the incoherent scattering compete over a wide range of magnitude of scattering vector, q, specifically when q is larger than q* ≈ 1/Rg, where Rg is the radius of gyration of scatterer. Therefore, it is important to determine the incoherent scattering intensity exactly to perform an accurate structural analysis from SANS data when Rgmore » is small, such as the aforementioned extracted coordination species. Although NPA is the best method for evaluating the incoherent scattering component for accurately determining the coherent scattering in SANS, this method is not used frequently in SANS data analysis because it is technically challenging. In this study, we successfully demonstrated that experimental determination of the incoherent scattering using NPA is suitable for sample systems containing a small scatterer with a weak coherent scattering intensity, such as extracted complexes in biphasic solvent extraction systems.« less

  16. Dynamin 2 regulates biphasic insulin secretion and plasma glucose homeostasis

    PubMed Central

    Fan, Fan; Ji, Chen; Wu, Yumei; Ferguson, Shawn M.; Tamarina, Natalia; Philipson, Louis H.; Lou, Xuelin

    2015-01-01

    Alterations in insulin granule exocytosis and endocytosis are paramount to pancreatic β cell dysfunction in diabetes mellitus. Here, using temporally controlled gene ablation specifically in β cells in mice, we identified an essential role of dynamin 2 GTPase in preserving normal biphasic insulin secretion and blood glucose homeostasis. Dynamin 2 deletion in β cells caused glucose intolerance and substantial reduction of the second phase of glucose-stimulated insulin secretion (GSIS); however, mutant β cells still maintained abundant insulin granules, with no signs of cell surface expansion. Compared with control β cells, real-time capacitance measurements demonstrated that exocytosis-endocytosis coupling was less efficient but not abolished; clathrin-mediated endocytosis (CME) was severely impaired at the step of membrane fission, which resulted in accumulation of clathrin-coated endocytic intermediates on the plasma membrane. Moreover, dynamin 2 ablation in β cells led to striking reorganization and enhancement of actin filaments, and insulin granule recruitment and mobilization were impaired at the later stage of GSIS. Together, our results demonstrate that dynamin 2 regulates insulin secretory capacity and dynamics in vivo through a mechanism depending on CME and F-actin remodeling. Moreover, this study indicates a potential pathophysiological link between endocytosis and diabetes mellitus. PMID:26413867

  17. The Upward Spiral of Adolescents' Positive School Experiences and Happiness: Investigating Reciprocal Effects over Time

    ERIC Educational Resources Information Center

    Stiglbauer, Barbara; Gnambs, Timo; Gamsjager, Manuela; Batinic, Bernad

    2013-01-01

    In line with self-determination theory and Fredrickson's (2001) broaden-and-build theory of positive emotions, this study adopts a positive perspective on students' school experiences and their general psychological functioning. The reciprocal effects of positive school experiences and happiness, a dimension of affective well-being, are examined…

  18. Early Effects of Radical Position Legality in Chinese: An ERP Study

    ERIC Educational Resources Information Center

    Yum, Yen Na; Su, I-Fan; Law, Sam-Po

    2015-01-01

    This study aimed to investigate the timecourse and neural underpinnings of the coding of radical positions in Chinese character reading. To isolate effects of radical positions, four types of pseudocharacters were created in which the constituent radicals appeared in positions varying in probability of occurrence, that is, Unique, Dominant,…

  19. Sentence-Position Effects on Children's Perception and Production of English Third Person Singular "-s"

    ERIC Educational Resources Information Center

    Sundara, Megha; Demuth, Katherine; Kuhl, Patricia K.

    2011-01-01

    Purpose: Two-year-olds produce third person singular "-s" more accurately on verbs in sentence-final position as compared with verbs in sentence-medial position. This study was designed to determine whether these sentence-position effects can be explained by perceptual factors. Method: For this purpose, the authors compared 22- and 27-month-olds'…

  20. Effects of positive intrathoracic pressure on pulmonary and systemic hemodynamics.

    PubMed

    Tyberg, J V; Grant, D A; Kingma, I; Moore, T D; Sun, Y; Smith, E R; Belenkie, I

    2000-02-01

    The Frank-Starling Law accounts for many changes in cardiac performance previously attributed to changes in contractility in that changes in contractility might have been incorrectly inferred from changing ventricular function curves (i.e. systolic performance plotted against filling pressure) if diastolic compliance also changed. To apply the Frank-Starling Law in the presence of changing diastolic compliance, it is necessary to measure end-diastolic volume directly or to calculate end-diastolic transmural pressure, which requires that pericardial pressure be known. Under most normal circumstances, increased intrathoracic pressure (and other interventions, such as vasodilators or lower-body negative pressure, that decrease central blood volume) decreases the transmural end-diastolic pressures of both ventricles, their end-diastolic volumes and stroke work. However, when ventricular interaction is significant, the effects of these interventions might be quite different; this may be important in patients with heart-failure. Although these interventions decrease RV transmural pressure, they may increase LV transmural pressure, end-diastolic volume, and thus stroke work by the Frank-Starling mechanism.

  1. The role of flow-independent viscoelasticity in the biphasic tensile and compressive responses of articular cartilage.

    PubMed

    Huang, C Y; Mow, V C; Ateshian, G A

    2001-10-01

    A long-standing challenge in the biomechanics of connective tissues (e.g., articular cartilage, ligament, tendon) has been the reported disparities between their tensile and compressive properties. In general, the intrinsic tensile properties of the solid matrices of these tissues are dictated by the collagen content and microstructural architecture, and the intrinsic compressive properties are dictated by their proteoglycan content and molecular organization as well as water content. These distinct materials give rise to a pronounced and experimentally well-documented nonlinear tension-compression stress-strain responses, as well as biphasic or intrinsic extracellular matrix viscoelastic responses. While many constitutive models of articular cartilage have captured one or more of these experimental responses, no single constitutive law has successfully described the uniaxial tensile and compressive responses of cartilage within the same framework. The objective of this study was to combine two previously proposed extensions of the biphasic theory of Mow et al. [1980, ASME J. Biomech. Eng., 102, pp. 73-84] to incorporate tension-compression nonlinearity as well as intrinsic viscoelasticity of the solid matrix of cartilage. The biphasic-conewise linear elastic model proposed by Soltz and Ateshian [2000, ASME J. Biomech. Eng., 122, pp. 576-586] and based on the bimodular stress-strain constitutive law introduced by Curnier et al. [1995, J. Elasticity, 37, pp. 1-38], as well as the biphasic poroviscoelastic model of Mak [1986, ASME J. Biomech. Eng., 108, pp. 123-130], which employs the quasi-linear viscoelastic model of Fung [1981, Biomechanics: Mechanical Properties of Living Tissues, Springer-Verlag, New York], were combined in a single model to analyze the response of cartilage to standard testing configurations. Results were compared to experimental data from the literature and it was found that a simultaneous prediction of compression and tension experiments of

  2. Ratio of phosphorylated HSP27 to nonphosphorylated HSP27 biphasically acts as a determinant of cellular fate in gemcitabine-resistant pancreatic cancer cells.

    PubMed

    Kang, Dongxu; Choi, Hye Jin; Kang, Sujin; Kim, So Young; Hwang, Yong-Sic; Je, Suyeon; Han, Zhezhu; Kim, Joo-Hang; Song, Jae J

    2015-04-01

    Gemcitabine has been used most commonly as an anticancer drug to treat advanced pancreatic cancer patients. However, intrinsic or acquired resistance of pancreatic cancer to gemcitabine was also developed, which leads to very low five-year survival rates. Here, we investigated whether cellular levels of HSP27 phosphorylation act as a determinant of cellular fate with gemcitabine. In addition we have demonstrated whether HSP27 downregulation effectively could overcome the acquisition of gemcitabine resistance by using transcriptomic analysis. We observed that gemcitabine induced p38/HSP27 phosphorylation and caused acquired resistance. After acquisition of gemcitabine resistance, cancer cells showed higher activity of NF-κB. NF-κB activity, as well as colony formation in gemcitabine-resistant pancreatic cancer cells, was significantly decreased by HSP27 downregulation and subsequent TRAIL treatment, showing that HSP27 was a common network mediator of gemcitabine/TRAIL-induced cell death. After transcriptomic analysis, gene fluctuation after HSP27 downregulation was very similar to that of pancreatic cancer cells susceptible to gemcitabine, and then in opposite position to that of acquired gemcitabine resistance, which makes it possible to downregulate HSP27 to overcome the acquired gemcitabine resistance to function as an overall survival network inhibitor. Most importantly, we demonstrated that the ratio of phosphorylated HSP27 to nonphosphorylated HSP27 rather than the cellular level of HSP27 itself acts biphasically as a determinant of cellular fate in gemcitabine-resistant pancreatic cancer cells.

  3. Estimation of the biphasic property in a female's menstrual cycle from cutaneous temperature measured during sleep.

    PubMed

    Chen, Wenxi; Kitazawa, Masumi; Togawa, Tatsuo

    2009-09-01

    This paper proposes a method to estimate a woman's menstrual cycle based on the hidden Markov model (HMM). A tiny device was developed that attaches around the abdominal region to measure cutaneous temperature at 10-min intervals during sleep. The measured temperature data were encoded as a two-dimensional image (QR code, i.e., quick response code) and displayed in the LCD window of the device. A mobile phone captured the QR code image, decoded the information and transmitted the data to a database server. The collected data were analyzed by three steps to estimate the biphasic temperature property in a menstrual cycle. The key step was an HMM-based step between preprocessing and postprocessing. A discrete Markov model, with two hidden phases, was assumed to represent higher- and lower-temperature phases during a menstrual cycle. The proposed method was verified by the data collected from 30 female participants, aged from 14 to 46, over six consecutive months. By comparing the estimated results with individual records from the participants, 71.6% of 190 menstrual cycles were correctly estimated. The sensitivity and positive predictability were 91.8 and 96.6%, respectively. This objective evaluation provides a promising approach for managing premenstrual syndrome and birth control.

  4. Longitudinal PET imaging demonstrates biphasic CAR T cell responses in survivors

    PubMed Central

    Vedvyas, Yogindra; Shevlin, Enda; Zaman, Marjan; Min, Irene M.; Park, Spencer; Park, Susan; Kwon, Keon-Woo; Smith, Turner; Luo, Yonghua; Kim, Dohyun; Kim, Young; Law, Benedict; Ting, Richard; Jin, Moonsoo M.

    2016-01-01

    Clinical monitoring of adoptive T cell transfer (ACT) utilizes serial blood analyses to discern T cell activity. While useful, these data are 1-dimensional and lack spatiotemporal information related to treatment efficacy or toxicity. We utilized a human genetic reporter, somatostatin receptor 2 (SSTR2), and PET, to quantitatively and longitudinally visualize whole-body T cell distribution and antitumor dynamics using a clinically approved radiotracer. Initial evaluations determined that SSTR2-expressing T cells were detectable at low densities with high sensitivity and specificity. SSTR2-based PET was applied to ACT of chimeric antigen receptor (CAR) T cells targeting intercellular adhesion molecule-1, which is overexpressed in anaplastic thyroid tumors. Timely CAR T cell infusions resulted in survival of tumor-bearing mice, while later infusions led to uniform death. Real-time PET imaging revealed biphasic T cell expansion and contraction at tumor sites among survivors, with peak tumor burden preceding peak T cell burden by several days. In contrast, nonsurvivors displayed unrelenting increases in tumor and T cell burden, indicating that tumor growth was outpacing T cell killing. Thus, longitudinal PET imaging of SSTR2-positive ACT dynamics enables prognostic, spatiotemporal monitoring with unprecedented clarity and detail to facilitate comprehensive therapy evaluation with potential for clinical translation. PMID:27882353

  5. Forging And Milling Contribution On Residual Stresses For A Textured Biphasic Titanium Alloy

    SciTech Connect

    Deleuze, C.; Fabre, A.; Barrallier, L.; Molinas, O.

    2011-01-17

    Ti-10V-2Fe-3Al is a biphasic titanium alloy ({alpha}+{beta}) used in aeronautical applications for its mechanical properties, such as its yield strength of 1200 MPa and it weighs 40% less than steel. This alloy is particularly useful for vital parts with complex geometry, because of its high forging capability. In order to predict the capability for fatigue lifetime, the designers need to know the residual stresses. X-Ray diffraction is the main experimental technique used to determine residual stresses on the surface. In this case, stress levels are primarily influenced by the complex forging and milling process. On this alloy in particular, it may be difficult to characterize stress due to modification of the microstructure close to the surface. Results obtained by x-ray analysis depend on the correct definition of the shape of the diffraction peaks. The more precisely defined the position of the peak, the more accurately the stresses are evaluated. This paper presents a method to detect if residual stresses can be characterized by x-ray diffraction. The characterization of hardness seems to be a relevant technique to quickly analyze the capability of x-ray diffraction to determine residual stresses.

  6. Histamine and spontaneous motor activity: biphasic changes, receptors involved and participation of the striatal dopamine system.

    PubMed

    Chiavegatto, S; Nasello, A G; Bernardi, M M

    1998-01-01

    The time- and dose-related effects of exogenous histamine on spontaneous motor activity and receptors involved were evaluated in male rats. Intracerebroventricular administration of histamine (5.4 and 54.3 nmol) produced a biphasic effect with initial transitory hypoactivity and later hyperactivity expressed by locomotion frequency in an open-field. The rearing frequencies were only reduced by all doses of histamine used. The histamine-induced hypoactivity was inhibited by the H3-antagonist thioperamide and was also induced by the H3-agonist N-alpha-methylhistamine. The histamine-induced hyperactivity phase was blocked by the H1-antagonist mepyramine. The H2-antagonist ranitidine increased locomotion and rearing frequencies. The participation of other neurotransmitters in the persistent hypokinetic effect induced by 135.8 nmol of histamine was determined by HPLC in the striatum and hypothalamus as counter-proof. A decreased DOPAC/DA ratio was observed only in the striatum. In the hypothalamus, low levels of 5HT were detected, probably not correlated with motor activity. In conclusion, the present results suggest that the exogenous histamine-induced hypoactivity response is probably due to activation of H3-receptors as heteroreceptors reducing the activity of the striatal dopaminergic system. This effect can partially overlap with the expression of the hyperactivity induced by H1-receptor activation. The participation of H2-receptors requires further investigation.

  7. The polyacetylenes falcarinol and falcarindiol affect stress responses in myotube cultures in a biphasic manner.

    PubMed

    Young, Jette F; Christensen, Lars P; Theil, Peter K; Oksbjerg, Niels

    2008-01-01

    The effects of the bioactive polyacetylenes, falcarinol and falcarindiol, present in carrots, celery, celeriac and other umbelliferous vegetables, on the stress responses in primary myotube cultures, were studied. Biphasic responses on cellular stress responses in myotube cultures were investigated by exposing them to various concentrations of falcarinol and falcarindiol for 24 h before testing effects of 100 microM H(2)O(2) on the intracellular formation of reactive oxygen species (ROS), transcription of the antioxidative enzyme cytosolic glutathione peroxidase (cGPx), and the heat shock proteins (HSP) HSP70 and HO1. At low concentrations (1.6 to 25 microM) polyacetylenes caused a slightly accelerated intra-cellular ROS formation, increased cGPx transcription and decreased HSP70 and HO1 transcription. The increased cGPx transcription may be interpreted as an adaptive response to the increased ROS formation and may have caused a reduced demand for the protective functions of the HSPs. ROS formation, however, was substantially decreased after pre-incubation with both polyacetylenes at 50 and 100 microM, the cGPx transcription was reduced and the HSP70 and HO1 transcription increased, indicating a need for the protective and repairing functions of the HSPs. In conclusion, pre-incubation with low concentrations of both polyacetylenes prior to H(2)O(2) exposure induced a cytoprotective effect whereas higher concentrations had adverse effects.

  8. The Polyacetylenes Falcarinol and Falcarindiol Affect Stress Responses in Myotube Cultures in a Biphasic Manner

    PubMed Central

    Young, Jette F.; Christensen, Lars P.; Theil, Peter K.; Oksbjerg, Niels

    2008-01-01

    The effects of the bioactive polyacetylenes, falcarinol and falcarindiol, present in carrots, celery, celeriac and other umbelliferous vegetables, on the stress responses in primary myotube cultures, were studied. Biphasic responses on cellular stress responses in myotube cultures were investigated by exposing them to various concentrations of falcarinol and falcarindiol for 24 h before testing effects of 100 μM H2O2 on the intracellular formation of reactive oxygen species (ROS), transcription of the antioxidative enzyme cytosolic glutathione peroxidase (cGPx), and the heat shock proteins (HSP) HSP70 and HO1. At low concentrations (1.6 to 25 μM) polyacetylenes caused a slightly accelerated intra-cellular ROS formation, increased cGPx transcription and decreased HSP70 and HO1 transcription. The increased cGPx transcription may be interpreted as an adaptive response to the increased ROS formation and may have caused a reduced demand for the protective functions of the HSPs. ROS formation, however, was substantially decreased after pre-incubation with both polyacetylenes at 50 and 100 μM, the cGPx transcription was reduced and the HSP70 and HO1 transcription increased, indicating a need for the protective and repairing functions of the HSPs. In conclusion, pre-incubation with low concentrations of both polyacetylenes prior to H2O2 exposure induced a cytoprotective effect whereas higher concentrations had adverse effects. PMID:18846258

  9. Design and hydraulic characteristics of a field-scale bi-phasic bioretention rain garden system for storm water management.

    PubMed

    Yang, H; Florence, D C; McCoy, E L; Dick, W A; Grewal, P S

    2009-01-01

    A field-scale bioretention rain garden system was constructed using a novel bi-phasic (i.e. sequence of anaerobic to aerobic) concept for improving retention and removal of storm water runoff pollutants. Hydraulic tests with bromide tracer and simulated runoff pollutants (nitrate-N, phosphate-P, Cu, Pb, and Zn) were performed in the system under a simulated continuous rainfall. The objectives of the tests were (1) to determine hydraulic characteristics of the system, and (2) to evaluate the movement of runoff pollutants through the system. For the 180 mm/24 h rainfall, the bi-phasic bioretention system effectively reduced both peak flow (approximately 70%) and runoff volume (approximately 42%). The breakthrough curves (BTCs) of bromide tracer suggest that the transport pattern of the system is similar to dispersed plug flow under this large runoff event. The BTCs of bromide showed mean 10% and 90% breakthrough times of 5.7 h and 12.5 h, respectively. Under the continuous rainfall, a significantly different transport pattern was found between each runoff pollutant. Nitrate-N was easily transported through the system with potential leaching risk from the initial soil medium, whereas phosphate-P and metals were significantly retained indicating sorption-mediated transport. These findings support the importance of hydraulics, in combination with the soil medium, when creating bioretention systems for bioremediation that are effective for various rainfall sizes and intervals.

  10. 5 CFR 335.101 - Effect of position change on status and tenure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Effect of position change on status and tenure. 335.101 Section 335.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PROMOTION AND INTERNAL PLACEMENT General Provisions § 335.101 Effect of position change on...

  11. 5 CFR 335.101 - Effect of position change on status and tenure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Effect of position change on status and tenure. 335.101 Section 335.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PROMOTION AND INTERNAL PLACEMENT General Provisions § 335.101 Effect of position change on...

  12. [Effects of centrifugation-related artificial gravity on the human organism. Positive and negative effects].

    PubMed

    Vil'-Vil'iams, I F; Kotovskaia, A R

    2003-01-01

    Data of investigations of the artificial gravity issues in centrifuge experiments in Russian, USA and Japan over the past 40 years were analyzed. Periodic +Gz centrifugation was used to prevent or eliminate body deconditioning after 3- to 56-d simulated microgravity, and to increase the body functional reserve (orthostatic stability) in ordinary life. Positive effects included prevention of a decline of gravitational stability and reduction or averting the negative effects of simulated microgravity on various physiological systems. Better results can be achieved by combining artificial g-loads with the well-proven methods of combating deconditioning, i.e. physical training on bicycle ergometer and induced hydration. Human tolerance of g-loads on a short-arm centrifuge with a high (100%) gravitational gradient was found no worse than on a mid-arm centrifuge with a lower (20%) gravitational gradient. Negative effects of +Gz on a short-arm centrifuge were revealed and counteracting measures were determined.

  13. Design of a novel integrated position sensor based on Hall effects for linear oscillating actuator

    NASA Astrophysics Data System (ADS)

    Wang, Tianyi; Yan, Liang; Jiao, Zongxia

    2015-07-01

    Linear oscillating actuator provides linear reciprocate motion directly without other auxiliary components, which is suitable for high integration applications in aerospace industry. Accurate position control is essential for linear oscillating motor and relies on concise measurement of mover position. However, most position measurements are dependent on external complicated sensors, which hinders further integration of linear oscillating actuation system. In this paper, a novel position sensing system for linear oscillating actuator based on Hall effects is proposed to achieve accurate and high integration measurement simultaneously. Axial sensing magnetic field with approximately linear relationship with position is created for direct and convenient measurement. Analytical model of sensing magnetic field is set up for optimization and validated by finite element method and experimental results. Finally, sensing magnets are integrated into motor prototype for experiments. Dynamic position results are tested in experiments and prove to be effective and accurate for position sensing with short-stroke.

  14. Design of a novel integrated position sensor based on Hall effects for linear oscillating actuator.

    PubMed

    Wang, Tianyi; Yan, Liang; Jiao, Zongxia

    2015-07-01

    Linear oscillating actuator provides linear reciprocate motion directly without other auxiliary components, which is suitable for high integration applications in aerospace industry. Accurate position control is essential for linear oscillating motor and relies on concise measurement of mover position. However, most position measurements are dependent on external complicated sensors, which hinders further integration of linear oscillating actuation system. In this paper, a novel position sensing system for linear oscillating actuator based on Hall effects is proposed to achieve accurate and high integration measurement simultaneously. Axial sensing magnetic field with approximately linear relationship with position is created for direct and convenient measurement. Analytical model of sensing magnetic field is set up for optimization and validated by finite element method and experimental results. Finally, sensing magnets are integrated into motor prototype for experiments. Dynamic position results are tested in experiments and prove to be effective and accurate for position sensing with short-stroke.

  15. Core-shell nanoreactors for efficient aqueous biphasic catalysis.

    PubMed

    Zhang, Xuewei; Cardozo, Andrés F; Chen, Si; Zhang, Wenjing; Julcour, Carine; Lansalot, Muriel; Blanco, Jean-François; Gayet, Florence; Delmas, Henri; Charleux, Bernadette; Manoury, Eric; D'Agosto, Franck; Poli, Rinaldo

    2014-11-17

    Water-borne phosphine-functionalized core-cross-linked micelles (CCM) consisting of a hydrophobic core and a hydrophilic shell were obtained as stable latexes by reversible addition-fragmentation chain transfer (RAFT) in water in a one-pot, three-step process. Initial homogeneous aqueous-phase copolymerization of methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA) is followed by copolymerization of styrene (S) and 4-diphenylphosphinostyrene (DPPS), yielding P(MAA-co-PEOMA)-b-P(S-co-DPPS) amphiphilic block copolymer micelles (M) by polymerization-induced self-assembly (PISA), and final micellar cross-linking with a mixture of S and diethylene glycol dimethacrylate. The CCM were characterized by dynamic light scattering and NMR spectroscopy to evaluate size, dispersity, stability, and the swelling ability of various organic substrates. Coordination of [Rh(acac)(CO)2 ] (acac=acetylacetonate) to the core-confined phosphine groups was rapid and quantitative. The CCM and M latexes were then used, in combination with [Rh(acac)(CO)2 ], to catalyze the aqueous biphasic hydroformylation of 1-octene, in which they showed high activity, recyclability, protection of the activated Rh center by the polymer scaffold, and low Rh leaching. The CCM latex gave slightly lower catalytic activity but significantly less Rh leaching than the M latex. A control experiment conducted in the presence of the sulfoxantphos ligand pointed to the action of the CCM as catalytic nanoreactors with substrate and product transport into and out of the polymer core, rather than as a surfactant in interfacial catalysis.

  16. Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

    NASA Astrophysics Data System (ADS)

    Metcalf, A. R.; Dutcher, C. S.

    2014-12-01

    Secondary organic aerosol (SOA) particles are nearly ubiquitous in the atmosphere and yet there remains large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. These aerosol interfaces can profoundly affect the fate of condensable organic compounds emitted into the atmosphere by altering the way in which organic vapors interact with the ambient aerosol. Aerosol interfaces affect particle internal structure, species uptake, equilibrium partitioning, activation to cloud condensation or ice nuclei, and optical properties. For example, organic thin films can shield the core of the aerosol from the ambient environment, which may disrupt equilibrium partitioning and mass transfer. To improve our ability to accurately predict the fate of SOA in the atmosphere, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Few technologies exist to accurately probe aerosol interfaces at atmospherically-relevant conditions. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred. Chemical compositions of the liquid phases studied here span a range of viscosities and include electrolyte and water soluble organic acid species often observed in the atmosphere, such as mixtures

  17. The upward spiral of adolescents' positive school experiences and happiness: investigating reciprocal effects over time.

    PubMed

    Stiglbauer, Barbara; Gnambs, Timo; Gamsjäger, Manuela; Batinic, Bernad

    2013-04-01

    In line with self-determination theory and Fredrickson's (2001) broaden-and-build theory of positive emotions, this study adopts a positive perspective on students' school experiences and their general psychological functioning. The reciprocal effects of positive school experiences and happiness, a dimension of affective well-being, are examined over the course of an academic year. Data were collected from 215 secondary school students at 5 measurement occasions. The results of longitudinal cross-lagged structural equation modeling support the notion of an upward spiral of positive school experiences and happiness over time. Positive school experiences had a stable lagged effect on happiness, and, in turn, happiness had a lagged effect on future positive school experiences.

  18. A biphasic viscohyperelastic fibril-reinforced model for articular cartilage: formulation and comparison with experimental data.

    PubMed

    García, José Jaime; Cortés, Daniel Humberto

    2007-01-01

    Experiments in articular cartilage have shown highly nonlinear stress-strain curves under finite deformations, nonlinear tension-compression response as well as intrinsic viscous effects of the proteoglycan matrix and the collagen fibers. A biphasic viscohyperelastic fibril-reinforced model is proposed here, which is able to describe the intrinsic viscoelasticity of the fibrillar and nonfibrillar components of the solid phase, the nonlinear tension-compression response and the nonlinear stress-strain curves under tension and compression. A viscohyperelastic constitutive equation was used for the matrix and the fibers encompassing, respectively, a hyperelastic function used previously for the matrix and a hyperelastic law used before to represent biological connective tissues. This model, implemented in an updated Lagrangian finite element code, displayed good ability to follow experimental stress-strain equilibrium curves under tension and compression for human humeral cartilage. In addition, curve fitting of experimental reaction force and lateral displacement unconfined compression curves showed that the inclusion of viscous effects in the matrix allows the description of experimental data with material properties for the fibers consistent with experimental tensile tests, suggesting that intrinsic viscous effects in the matrix of articular cartilage plays an important role in the mechanical response of the tissue.

  19. Studies on the Mechanism of Heterochromatic Position Effect at the Rosy Locus of DROSOPHILA MELANOGASTER

    PubMed Central

    Rushlow, C. A.; Bender, W.; Chovnick, A.

    1984-01-01

    Experiments are described that extend the characterization of position effect variants of the rosy locus and test possible mechanisms of heterochromatic position effect.—Rosy position effect variants exhibit a variegated phenotype with respect to xanthine dehydrogenase activity in malpighian tubules.—The breakpoints of the position effect mutations are located on the DNA map of the rosy region outside of the rosy locus DNA; ryps1136 is located in the DNA of the l(3)S12 gene immediately proximal to rosy, whereas ryps1149 is located some 15 kb distal to rosy in the pic locus.—Southern blot experiments are described that test and reject the notion that heterochromatic position effect results from underreplication of the position-affected gene. Rather, the results of Northern blots serve to direct attention to position effect as a defect in transcription.—Histone region deletion heterozygosity and butyrate-feeding experiments failed to exhibit specific suppression of position effect at the rosy locus. PMID:6149972

  20. Positive effects of bacterial diversity on ecosystem functioning driven by complementarity effects in a bioremediation context.

    PubMed

    Venail, Patrick A; Vives, Martha J

    2013-01-01

    Despite their importance as ecosystem drivers, our understanding of the influence of bacterial diversity on ecosystem functioning is limited. After identifying twelve bacterial strains from two petroleum-contaminated sites, we experimentally explored the impact of biodiversity on total density by manipulating the number of strains in culture. Irrespective of the origin of the bacteria relative to the contaminant, biodiversity positively influenced total density. However, bacteria cultured in the crude oil of their origin (autochthonous) reached higher densities than bacteria from another origin (allochthonous) and the relationship between diversity and density was stronger for autochthonous bacteria. By measuring the relative contribution of each strain to total density we showed that the observed positive effect of increasing diversity on total density was mainly due to positive interactions among species and not the presence of a particular species. Our findings can be explained by the complex chemical composition of crude oil and the necessity of a diverse array of organisms with complementary enzymatic capacities to achieve its degradation. The long term exposure to a contaminant may have allowed different bacteria to become adapted to the use of different fractions of the crude, resulting in higher complementarity in resource use in autochthonous bacteria compared to allochthonous ones. Our results could help improve the success of bioaugmentation as a bioremediation technique by suggesting the use of a diversified set of autochthonous organisms.

  1. The effect of loving-kindness meditation on positive emotions: a meta-analytic review.

    PubMed

    Zeng, Xianglong; Chiu, Cleo P K; Wang, Rong; Oei, Tian P S; Leung, Freedom Y K

    2015-01-01

    While it has been suggested that loving-kindness meditation (LKM) is an effective practice for promoting positive emotions, the empirical evidence in the literature remains unclear. Here, we provide a systematic review of 24 empirical studies (N = 1759) on LKM with self-reported positive emotions. The effect of LKM on positive emotions was estimated with meta-analysis, and the influence of variations across LKM interventions was further explored with subgroup analysis and meta-regression. The meta-analysis showed that (1) medium effect sizes for LKM interventions on daily positive emotions in both wait-list controlled RCTs and non-RCT studies; and (2) small to large effect sizes for the on-going practice of LKM on immediate positive emotions across different comparisons. Further analysis showed that (1) interventions focused on loving-kindness had medium effect size, but interventions focused on compassion showed small effect sizes; (2) the length of interventions and the time spent on meditation did not influence the effect sizes, but the studies without didactic components in interventions had small effect sizes. A few individual studies reported that the nature of positive emotions and individual differences also influenced the results. In sum, LKM practice and interventions are effective in enhancing positive emotions, but more studies are needed to identify the active components of the interventions, to compare different psychological operations, and to explore the applicability in clinical populations.

  2. The effect of loving-kindness meditation on positive emotions: a meta-analytic review

    PubMed Central

    Zeng, Xianglong; Chiu, Cleo P. K.; Wang, Rong; Oei, Tian P. S.; Leung, Freedom Y. K.

    2015-01-01

    While it has been suggested that loving-kindness meditation (LKM) is an effective practice for promoting positive emotions, the empirical evidence in the literature remains unclear. Here, we provide a systematic review of 24 empirical studies (N = 1759) on LKM with self-reported positive emotions. The effect of LKM on positive emotions was estimated with meta-analysis, and the influence of variations across LKM interventions was further explored with subgroup analysis and meta-regression. The meta-analysis showed that (1) medium effect sizes for LKM interventions on daily positive emotions in both wait-list controlled RCTs and non-RCT studies; and (2) small to large effect sizes for the on-going practice of LKM on immediate positive emotions across different comparisons. Further analysis showed that (1) interventions focused on loving-kindness had medium effect size, but interventions focused on compassion showed small effect sizes; (2) the length of interventions and the time spent on meditation did not influence the effect sizes, but the studies without didactic components in interventions had small effect sizes. A few individual studies reported that the nature of positive emotions and individual differences also influenced the results. In sum, LKM practice and interventions are effective in enhancing positive emotions, but more studies are needed to identify the active components of the interventions, to compare different psychological operations, and to explore the applicability in clinical populations. PMID:26579061

  3. Two-temperature stage biphasic CO2-H2O pretreatment of lignocellulosic biomass at high solid loadings.

    PubMed

    Luterbacher, Jeremy S; Tester, Jefferson W; Walker, Larry P

    2012-06-01

    Most biomass pretreatment processes for monosaccharide production are run at low-solid concentration (<10 wt%) and use significant amounts of chemical catalysts. Biphasic CO(2) -H(2) O mixtures could provide a more sustainable pretreatment medium while using high-solid contents. Using a stirred reactor for high solids (40 wt%, biomass water mixture) biphasic CO(2)-H(2) O pretreatment of lignocellulosic biomass allowed us to explore the effects of particle size and mixing on mixed hardwood and switchgrass pretreatment. Subsequently, a two-temperature stage pretreatment was introduced. After optimization, a short high-temperature stage at 210°C (16 min for hardwood and 1 min for switchgrass) was followed by a long low-temperature stage at 160°C for 60 min. Glucan to glucose conversion yields of 83% for hardwood and 80% for switchgrass were obtained. Total molar sugar yields of 65% and 55% were obtained for wood and switchgrass, respectively, which consisted of a 10% points improvement over those obtained during our previous study despite a 10-fold increase in particle size. These yields are similar to those obtained with other major pretreatment technologies for wood and within 10% of major technologies for switchgrass despite the absence of chemical catalysts, the use of large particles (0.95 cm) and high solid contents (40 wt%).

  4. Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

    PubMed

    Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

    2008-02-28

    The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

  5. AIC649 Induces a Bi-Phasic Treatment Response in the Woodchuck Model of Chronic Hepatitis B

    PubMed Central

    Paulsen, Daniela; Weber, Olaf; Ruebsamen-Schaeff, Helga; Tennant, Bud C.; Menne, Stephan

    2015-01-01

    AIC649 has been shown to directly address the antigen presenting cell arm of the host immune defense leading to a regulated cytokine release and activation of T cell responses. In the present study we analyzed the antiviral efficacy of AIC649 as well as its potential to induce functional cure in animal models for chronic hepatitis B. Hepatitis B virus transgenic mice and chronically woodchuck hepatitis virus (WHV) infected woodchucks were treated with AIC649, respectively. In the mouse system AIC649 decreased the hepatitis B virus titer as effective as the “gold standard”, Tenofovir. Interestingly, AIC649-treated chronically WHV infected woodchucks displayed a bi-phasic pattern of response: The marker for functional cure—hepatitis surface antigen—first increased but subsequently decreased even after cessation of treatment to significantly reduced levels. We hypothesize that the observed bi-phasic response pattern to AIC649 treatment reflects a physiologically “concerted”, reconstituted immune response against WHV and therefore may indicate a potential for inducing functional cure in HBV-infected patients. PMID:26656974

  6. FTIR study on phase behavior of magnesium-doped biphasic calcium phosphate synthesized via sol-gel method

    NASA Astrophysics Data System (ADS)

    Toibah, A. R.; Sopyan, I.; Yuhazri, Y. Mohd; Jeefferie, R. A.; Nooririnah, O.

    2012-06-01

    Incorporation of metal as sintering additive is a simple way to improve physical and mechanical properties of biphasic calcium phosphate (BCP) materials as well as its performance in biomedical applications. In this work, magnesium (Mg) was incorporated into the BCP as sintering additive to improve the properties of BCP. The aim of this work was to study the effect of Mg doping to the BCP on its phase behavior. Mg-doped BCP powders have been synthesized via sol-gel method. The as prepared powders at different Mg concentration were calcined at different temperatures ranged from 500°C to 900°C. FT-IR technique was used to study the phase behavior and thermal stability of as prepared powders. FT-IR study revealed that the intensity of the OH band of HA phase was increased with the powder crystallinity and calcination temperature. FT-IR analysis confirmed the formation of biphasic mixtures of HA and Mg stabilized β-TCP in the synthesized powders when calcined at high temperatures as bands of HPO4-2 and P2O7-4 decreased. Moreover, FT-IR study also showed that the intensity of peak resolution of OH and PO4 bands are viewed less intensity with the increased in Mg percent concentration. FT-IR also revealed the presence of stable phase of P2O5 band at 400-450 cm-1 which promotes the crystal growth Mg-doped BCP powder.

  7. Process boundaries of irreversible scCO2 -assisted phase separation in biphasic whole-cell biocatalysis.

    PubMed

    Brandenbusch, Christoph; Glonke, Sebastian; Collins, Jonathan; Hoffrogge, Raimund; Grunwald, Klaudia; Bühler, Bruno; Schmid, Andreas; Sadowski, Gabriele

    2015-11-01

    The formation of stable emulsions in biphasic biotransformations catalyzed by microbial cells turned out to be a major hurdle for industrial implementation. Recently, a cost-effective and efficient downstream processing approach, using supercritical carbon dioxide (scCO2 ) for both irreversible emulsion destabilization (enabling complete phase separation within minutes of emulsion treatment) and product purification via extraction has been proposed by Brandenbusch et al. (2010). One of the key factors for a further development and scale-up of the approach is the understanding of the mechanism underlying scCO2 -assisted phase separation. A systematic approach was applied within this work to investigate the various factors influencing phase separation during scCO2 treatment (that is pressure, exposure of the cells to CO2 , and changes of cell surface properties). It was shown that cell toxification and cell disrupture are not responsible for emulsion destabilization. Proteins from the aqueous phase partially adsorb to cells present at the aqueous-organic interface, causing hydrophobic cell surface characteristics, and thus contribute to emulsion stabilization. By investigating the change in cell-surface hydrophobicity of these cells during CO2 treatment, it was found that a combination of catastrophic phase inversion and desorption of proteins from the cell surface is responsible for irreversible scCO2 mediated phase separation. These findings are essential for the definition of process windows for scCO2 -assisted phase separation in biphasic whole-cell biocatalysis.

  8. Effects of Position and Operator on High-frequency Ultrasound Scan Quality

    PubMed Central

    Burk, Ruth S.; Parker, Angela; Sievers, Lisa; Rooney, Melissa B.; Pepperl, Anathea; Schubert, Christine M.; Grap, Mary Jo

    2015-01-01

    Objectives High-frequency ultrasound may evaluate those at risk for pressure ulcers. Images may be obtained by clinicians with limited training. The prone position is recommended for obtaining sacral scans but may not be feasible in the critically ill. This study investigated image quality using multiple operators and a variety of patient positions. Research Methodology Sacral scans were performed in three randomized positions in 50 volunteers by three different investigators using a 20 MHz ultrasound system. General linear models and ANOVA random effects models were used to examine the effects of operator and position on image quality rating, and measures of dermal thickness, and dermal density. Results The best scan for each position and operator was used for analysis (N=447 images). Image rating varied by operator (p=0.0004), although mean ratings were 3.5 or above for all operators. Dermal thickness was less for the prone position than in 90° or 60° side-lying positions (p=0.0137, p=0.0003). Dermal density was lower for the prone position than for the 90° or 60° positions (p<0.0001 for both). Conclusions These data show that overall scan quality was acceptable in all positions with all operators. However, differences were found between side-lying positions and the prone for dermal thickness and dermal density measures. PMID:25636253

  9. Clinical effect of a positive surgical margin after hepatectomy on survival of patients with intrahepatic cholangiocarcinoma

    PubMed Central

    Yeh, Chun-Nan; Hsieh, Feng-Jen; Chiang, Kun-Chun; Chen, Jen-Shi; Yeh, Ta-Sen; Jan, Yi-Yin; Chen, Miin-Fu

    2015-01-01

    Background Several unfavorable prognostic factors have been proposed for peripheral cholangiocarcinoma (PCC) in patients undergoing hepatectomy, including gross type of tumor, vascular invasion, lymph node metastasis, a high carbohydrate antigen 19-9 level, and a positive resection margin. However, the clinical effect of a positive surgical margin on the survival of patients with PCC after hepatectomy still needs to be clarified due to conflicting results. Methods A total of 224 PCC patients who underwent hepatic resection with curative intent between 1977 and 2007 were retrospectively reviewed. Eighty-nine patients had a positive resection margin, with 62 having a microscopically positive margin and 27 a grossly positive margin (R2). The clinicopathological features, outcomes, and recurrence pattern were compared with patients with curative hepatectomy. Results PCC patients with hepatolithiasis, periductal infiltrative or periductal infiltrative mixed with mass-forming growth, higher T stage, and more advanced stage tended to have higher positive resection margin rates after hepatectomy. PCC patients who underwent curative hepatectomy had a significantly higher survival rate than did those with a positive surgical margin. When PCC patients underwent hepatectomy with a positive resection margin, the histological grade of the tumor, nodal positivity, and chemotherapy significantly affected overall survival. Locoregional recurrence was the most common pattern of recurrence. Conclusion A positive resection margin had an unfavorable effect on overall survival in PCC patients undergoing hepatectomy. In these patients, the prognosis was determined by the biology of the tumor, including differentiation and nodal positivity, and chemotherapy increased overall survival. PMID:25552905

  10. Positional accommodative intraocular lens power error induced by the estimation of the corneal power and the effective lens position

    PubMed Central

    Piñero, David P; Camps, Vicente J; Ramón, María L; Mateo, Verónica; Pérez-Cambrodí, Rafael J

    2015-01-01

    Purpose: To evaluate the predictability of the refractive correction achieved with a positional accommodating intraocular lenses (IOL) and to develop a potential optimization of it by minimizing the error associated with the keratometric estimation of the corneal power and by developing a predictive formula for the effective lens position (ELP). Materials and Methods: Clinical data from 25 eyes of 14 patients (age range, 52–77 years) and undergoing cataract surgery with implantation of the accommodating IOL Crystalens HD (Bausch and Lomb) were retrospectively reviewed. In all cases, the calculation of an adjusted IOL power (PIOLadj) based on Gaussian optics considering the residual refractive error was done using a variable keratometric index value (nkadj) for corneal power estimation with and without using an estimation algorithm for ELP obtained by multiple regression analysis (ELPadj). PIOLadj was compared to the real IOL power implanted (PIOLReal, calculated with the SRK-T formula) and also to the values estimated by the Haigis, HofferQ, and Holladay I formulas. Results: No statistically significant differences were found between PIOLReal and PIOLadj when ELPadj was used (P = 0.10), with a range of agreement between calculations of 1.23 D. In contrast, PIOLReal was significantly higher when compared to PIOLadj without using ELPadj and also compared to the values estimated by the other formulas. Conclusions: Predictable refractive outcomes can be obtained with the accommodating IOL Crystalens HD using a variable keratometric index for corneal power estimation and by estimating ELP with an algorithm dependent on anatomical factors and age. PMID:26139807

  11. A critical assessment of the mechanisms governing the formation of aqueous biphasic systems composed of protic ionic liquids and polyethylene glycol†

    PubMed Central

    Cláudio, Ana Filipa M.; Pereira, Jorge F. B.; McCrary, Parker D.; Freire, Mara G.; Coutinho, João A. P.; Rogers, Robin D.

    2017-01-01

    An extensive study on the formation of aqueous biphasic systems (ABS) using aqueous solutions of protic ionic liquids (PILs) and polyethylene glycol (PEG) was performed in order to understand the mechanisms underlying the phase separation. Aqueous solutions of PEG polymers with different molecular weights (600, 1000, 2000, and 3400 g mol−1) and several N-alkyl-, dialkyl-, and trialkyl-ammonium salts of acetate, propanoate, butanoate, hexanoate and octanoate were prepared and their ability to form ABS at several temperatures assessed. The ternary liquid–liquid phase diagrams were determined at several temperatures, as well as binary PIL (or salt)-PEG-1000 and salt-water solubility data to better clarify the mechanisms responsible for the phase separation. All data gathered indicate that the formation of PEG–PIL-based ABS is mainly governed by the PIL–PEG mutual interactions, where PILs with a higher solubility in the polymer exhibit a lower aptitude to form ABS displaying thus a smaller biphasic region, for which a direct correlation was identified. The effects of the molecular weight and temperature of the polymer were also addressed. The increase of the PEG hydrophobicity or molecular weight favours the phase separation, whereas the effect of temperature was found to be more complex and dependent on the nature of the PIL, with an increase or decrease of the biphasic regime with an increase in temperature. PMID:27774550

  12. Legacy of road salt: Apparent positive larval effects counteracted by negative postmetamorphic effects in wood frogs.

    PubMed

    Dananay, Kacey L; Krynak, Katherine L; Krynak, Timothy J; Benard, Michael F

    2015-10-01

    Road salt runoff has potentially large effects on wetland communities, but is typically investigated in short-term laboratory trials. The authors investigated effects of road salt contamination on wood frogs (Rana sylvatica) by combining a field survey with 2 separate experiments. The field survey tested whether wood frog larval traits were associated with road salt contamination in natural wetlands. As conductivity increased, wood frog larvae were less abundant, but those found were larger. In the first experiment of the present study, the authors raised larvae in outdoor artificial ponds under 4 salt concentrations and measured larval vital rates, algal biomass, and zooplankton abundance. Salt significantly increased larval growth, algal biomass, and decreased zooplankton abundance. In the second experiment, the authors raised larvae to metamorphosis in the presence and absence of salt contamination and followed resulting juvenile frogs in terrestrial pens at high and low densities. Exposure to road salt as larvae caused juvenile frogs to have greater mortality in low-density terrestrial environments, possibly because of altered energy allocation, changes in behavior, or reduced immune defenses. The present study suggests that low concentrations of road salt can have positive effects on larval growth yet negative effects on juvenile survival. These results emphasize the importance of testing for effects of contaminants acting through food webs and across multiple life stages as well as the potential for population-level consequences in natural environments.

  13. Biphasic responses of human vascular smooth muscle cells to magnesium ion

    PubMed Central

    Ma, Jun; Zhao, Nan; Zhu, Donghui

    2016-01-01

    Magnesium-based alloys are promising in biodegradable cardiovascular stent applications. The degradation products of magnesium stents may have significant impacts on the surrounding vascular cells. However, knowledge on the interactions between magnesium ion and vascular cells at the molecular and cellular levels is still largely missing. Vascular smooth muscle cell (SMC) plays an important role in the pathogenesis of restenosis and wound healing after stent implantation. This study evaluated the short-term effects of extracellular magnesium ion (Mg2+) on the cellular behaviors of SMCs. Cellular responses to Mg2+ were biphasic and in a concentration-dependent manner. Low concentrations (10 mM) of Mg2+ increased cell viability, cell proliferation rate, cell adhesion, cell spreading, cell migration rate, and actin expression. In contrast, higher concentrations (40–60 mM) of Mg2+ had deleterious effects on cells. Gene expression analysis revealed that Mg2+ altered the expressions of genes mostly related to cell adhesion, cell injury, angiogenesis, inflammation, coagulation, and cell growth. Finding from this study provides some valuable information on SMC responses toward magnesium ions at the cellular and molecular levels, and guidance for future controlled release of magnesium from the stent material. PMID:26402437

  14. Biphasic responses of human vascular smooth muscle cells to magnesium ion.

    PubMed

    Ma, Jun; Zhao, Nan; Zhu, Donghui

    2016-02-01

    Magnesium-based alloys are promising in biodegradable cardiovascular stent applications. The degradation products of magnesium stents may have significant impacts on the surrounding vascular cells. However, knowledge on the interactions between magnesium ion and vascular cells at the molecular and cellular levels is still largely missing. Vascular smooth muscle cell (SMC) plays an important role in the pathogenesis of restenosis and wound healing after stent implantation. This study evaluated the short-term effects of extracellular magnesium ion (Mg(2+)) on the cellular behaviors of SMCs. Cellular responses to Mg(2+) were biphasic and in a concentration-dependent manner. Low concentrations (10 mM) of Mg(2+) increased cell viability, cell proliferation rate, cell adhesion, cell spreading, cell migration rate, and actin expression. In contrast, higher concentrations (40-60 mM) of Mg(2+) had deleterious effects on cells. Gene expression analysis revealed that Mg(2+) altered the expressions of genes mostly related to cell adhesion, cell injury, angiogenesis, inflammation, coagulation, and cell growth. Finding from this study provides some valuable information on SMC responses toward magnesium ions at the cellular and molecular levels, and guidance for future controlled release of magnesium from the stent material.

  15. Biphasic modulation of fatty acid synthase by hydrogen peroxide in Saccharomyces cerevisiae.

    PubMed

    Matias, Ana C; Marinho, H Susana; Cyrne, Luísa; Herrero, Enrique; Antunes, Fernando

    2011-11-01

    Taking into account published contradictory results concerning the regulation of fatty acid synthase (Fas) by H(2)O(2), we carried out a systematic study where two methods of H(2)O(2) delivery (steady-state and bolus addition) and the effect of a wide range of H(2)O(2) concentrations were investigated. A decrease in Fas activity was observed for cells exposed to 100 and 150μM H(2)O(2) in a steady-state, while a bolus addition of the same H(2)O(2) concentrations did not alter Fas activity. Similar results were observed for the mRNA levels of FAS1, the gene that encodes Fas subunit β. However, the exposure to a steady-state 50μM H(2)O(2) dose lead to an increase in FAS1 mRNA levels, showing a biphasic modulation of Fas by H(2)O(2). The results obtained emphasize that cellular effects of H(2)O(2) can vary over a narrow range of concentrations. Therefore, a tight control of H(2)O(2) exposure, which can be achieved by exposing H(2)O(2) in a steady-state, is important for cellular studies of H(2)O(2)-dependent redox regulation.

  16. Biphasic modeling of brain tumor biomechanics and response to radiation treatment.

    PubMed

    Angeli, Stelios; Stylianopoulos, Triantafyllos

    2016-06-14

    Biomechanical forces are central in tumor progression and response to treatment. This becomes more important in brain cancers where tumors are surrounded by tissues with different mechanical properties. Existing mathematical models ignore direct mechanical interactions of the tumor with the normal brain. Here, we developed a clinically relevant model, which predicts tumor growth accounting directly for mechanical interactions. A three-dimensional model of the gray and white matter and the cerebrospinal fluid was constructed from magnetic resonance images of a normal brain. Subsequently, a biphasic tissue growth theory for an initial tumor seed was employed, incorporating the effects of radiotherapy. Additionally, three different sets of brain tissue properties taken from the literature were used to investigate their effect on tumor growth. Results show the evolution of solid stress and interstitial fluid pressure within the tumor and the normal brain. Heterogeneous distribution of the solid stress exerted on the tumor resulted in a 35% spatial variation in cancer cell proliferation. Interestingly, the model predicted that distant from the tumor, normal tissues still undergo significant deformations while it was found that intratumoral fluid pressure is elevated. Our predictions relate to clinical symptoms of brain cancers and present useful tools for therapy planning.

  17. Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

    SciTech Connect

    Oothoudt, M.; Pillai, C.; Zumbro, M.

    1997-08-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances.

  18. Small biphase wellhead plant for the Cerro Prieto Mexico geothermal field

    SciTech Connect

    Oropeza, A.; Hays, L.

    1996-12-31

    In a system of geothermal wells in a geothermal field, there are different production conditions of the flows, temperatures and pressures. At plants where the installed capacity requires the use of many wells, it is necessary to regulate the well`s pressure to ensure a stable condition for the turbines. Reducing the steam pressure on the wellhead is achieved by using an orifice plate (flash orifice). Use of an orifice plate results in a waste or loss of well pressure that could be utilized for production of electricity. The Cerro Prieto field, operated by the Comision Federal de Electricidad (CFE), has many wells operating at a very high pressure and producing a lot of water. Much of this pressure and water is not utilized in the production of electricity. With the purpose of taking advantage of this pressure CFE has evaluated a proposal by Biphase Energy Co. Biphase has designed and patented a turbine that works directly with the steam and water mixture coming from the wellhead, acting as a separator. Biphase has developed a model of its turbine and successfully operated it in Coso Hot Springs California. Knowing this CFE has signed an agreement with Biphase Energy Company to install and operate a biphasic turbine at the Cerro Prieto geothermal field located near Mexicali, Mexico.

  19. Evaluation of the finite element software ABAQUS for biomechanical modelling of biphasic tissues.

    PubMed

    Wu, J Z; Herzog, W; Epstein, M

    1998-02-01

    The biphasic cartilage model proposed by Mow et al. (1980) has proven successful to capture the essential mechanical features of articular cartilage. In order to analyse the joint contact mechanics in real, anatomical joints, the cartilage model needs to be implemented into a suitable finite element code to approximate the irregular surface geometries of such joints. However, systematic and extensive evaluation of the capacity of commercial software for modelling the contact mechanics with biphasic cartilage layers has not been made. This research was aimed at evaluating the commercial finite element software ABAQUS for analysing biphasic soft tissues. The solutions obtained using ABAQUS were compared with those obtained using other finite element models and analytical solutions for three numerical tests: an unconfined indentation test, a test with the contact of a spherical cartilage surface with a rigid plate, and an axi-symmetric joint contact test. It was concluded that the biphasic cartilage model can be implemented into the commercial finite element software ABAQUS to analyse practical joint contact problems with biphasic articular cartilage layers.

  20. The biphasic nature of hypoxia-induced directional migration of activated human hepatic stellate cells.

    PubMed

    Novo, Erica; Povero, Davide; Busletta, Chiara; Paternostro, Claudia; di Bonzo, Lorenzo Valfrè; Cannito, Stefania; Compagnone, Alessandra; Bandino, Andrea; Marra, Fabio; Colombatto, Sebastiano; David, Ezio; Pinzani, Massimo; Parola, Maurizio

    2012-03-01

    Liver fibrogenesis is sustained by pro-fibrogenic myofibroblast-like cells (MFs), mainly originating from activated hepatic stellate cells (HSC/MFs) or portal (myo)fibroblasts, and is favoured by hypoxia-dependent angiogenesis. Human HSC/MFs were reported to express vascular-endothelial growth factor (VEGF) and VEGF-receptor type 2 and to migrate under hypoxic conditions. This study was designed to investigate early and delayed signalling mechanisms involved in hypoxia-induced migration of human HSC/MFs. Signal transduction pathways and intracellular generation of reactive oxygen species (ROS) were evaluated by integrating morphological, cell, and molecular biology techniques. Non-oriented and oriented migration were evaluated by using wound healing assay and the modified Boyden's chamber assay, respectively. The data indicate that hypoxia-induced migration of HSC/MFs is a biphasic process characterized by the following sequence of events: (a) an early (15 min) and mitochondria-related increased generation of intracellular ROS which (b) was sufficient to switch on activation of ERK1/2 and JNK1/2 that were responsible for the early phase of oriented migration; (c) a delayed and HIF-1α-dependent increase in VEGF expression (facilitated by ROS) and its progressive, time-dependent release in the extracellular medium that (d) was mainly responsible for sustained migration of HSC/MFs. Finally, immunohistochemistry performed on HCV-related fibrotic/cirrhotic livers revealed HIF-2α and haem-oxygenase-1 positivity in hepatocytes and α-SMA-positive MFs, indicating that MFs were likely to be exposed in vivo to both hypoxia and oxidative stress. In conclusion, hypoxia-induced migration of HSC/MFs involves an early, mitochondrial-dependent ROS-mediated activation of ERK and JNK, followed by a delayed- and HIF-1α-dependent up-regulation and release of VEGF.

  1. The Effects of Positive Behavior Interventions and Support on Changing the Behavior of Red Zone Students

    ERIC Educational Resources Information Center

    Robinson, Fredrick

    2012-01-01

    In order to improve culture, safety, and climate, numerous schools nationwide are implementing Positive Behavior Interventions and Support (PBIS). The purpose of this study was to examine the effectiveness of the Positive Behavior Interventions and Support (PBIS) model for reducing high-risk behaviors of students identified as red zone. The…

  2. The Relative Position Priming Effect Depends on Whether Letters Are Vowels or Consonants

    ERIC Educational Resources Information Center

    Dunabeitia, Jon Andoni; Carreiras, Manuel

    2011-01-01

    The relative position priming effect is a type of subset priming in which target word recognition is facilitated as a consequence of priming the word with some of its letters, maintaining their relative position (e.g., "csn" as a prime for "casino"). Five experiments were conducted to test whether vowel-only and consonant-only…

  3. A Cross-Cultural Examination of the Positivity Effect in Memory: United States vs. China

    ERIC Educational Resources Information Center

    Chung, Christie; Lin, Ziyong

    2012-01-01

    Many studies conducted in the United States (U.S.) have documented a positivity effect in aging--a tendency for older adults to remember more positive than negative information in comparison to young adults. Despite this cognitive emotional benefit, U.S. adults still hold a more negative view of aging compared to adults in Asia. We hypothesized…

  4. The Effects of Positive and Negative Mood on Cognition and Motivation in Multimedia Learning Environment

    ERIC Educational Resources Information Center

    Liew, Tze Wei; Tan, Su-Mae

    2016-01-01

    The Cognitive-Affective Theory of Learning with Media framework posits that the multimedia learning process is mediated by the learner's mood. Recent studies have shown that positive mood has a facilitating effect on multimedia learning. Though literature has shown that negative mood encourages an individual to engage in a more systematic,…

  5. Documenting the Implementation and Effects of Positive Behavior Support in an Alternative Educational Setting

    ERIC Educational Resources Information Center

    Adolphson, S. Lillian

    2013-01-01

    Positive behavior support (PBS) is a preventative and proactive system of managing behavior that is being used in the United States and other countries. Positive behavior support has been successfully implemented in typical school settings for students with and without disabilities. However, research documenting the implementation and effects of…

  6. The Effects of Implementing a Positive Behavior Intervention Support Program on Office Discipline Referrals

    ERIC Educational Resources Information Center

    Thomas, Cheryl Denise

    2015-01-01

    The purpose of this study was to determine if the implementation of PBIS (Positive Behavioral Intervention Support) program had a positive significant effect in decreasing office discipline referrals in a local elementary school. A sample independent t-Test was used to examine data on the school's average office discipline referrals for two years…

  7. Effects of Positive and Negative Moods on Helping Tasks Having Pleasant or Unpleasant Consequences.

    ERIC Educational Resources Information Center

    Shaffer, David R.; Graziano, William G.

    Research on altruism has found that persons experiencing either positive or negative moods are often more altruistically inclined than their counterparts experiencing neutral affective states. Prosocial behavior may become self-gratifying and altruism may be a form of hedonism. A field study investigated the effects of positive and negative moods…

  8. Effects of body position on transient evoked otoacoustic emissions: the clinical perspective.

    PubMed

    Fukai, Natasha; Shyu, Jenny; Driscoll, Carlie; Kei, Joseph

    2005-01-01

    The present study investigated body position effects on transient evoked otoacoustic emission (TEOAE) recordings of clinical significance. Sixty adults (30 males, 30 females) were assessed using the Otodynamics ILO88 Analyzer in three positions (sitting, supine, and side-lying). Results indicated significant positional effects on the TEOAE parameters of A-B difference, noise, whole wave reproducibility, and response levels. These differences included higher noise levels in supine and side-lying positions in comparison to the upright sitting position. Lower whole wave reproducibility measurements, and higher response amplitudes, in the side-lying position compared with supine and seated positions were also observed. No significant effects were evident for signal-to-noise ratio or band reproducibility. Given the lack of significant body position effects on these latter parameters and the infrequent clinical use of the other parameters in isolation, there was no evidence to suggest the future need for major review of current pass/fail criteria or of the standard test protocol.

  9. Why Do We Mipsell the Middle of Words? Orthographic Texture and the Serial Position Effect

    ERIC Educational Resources Information Center

    Jones, Angela C.

    2013-01-01

    In the current set of studies, a new hypothesis regarding the cause of the commonly observed U-shaped serial position effect (SPE) in spelling is introduced and tested. Instead of greater competition during output or weaker positional representation for word-medial letters, commonly accepted explanations for the cause of the SPE, the…

  10. Influence of saline solution on hydration behavior of β-dicalcium silicate in comparison with biphasic calcium phosphate/hydroxyapatite bio-ceramics.

    PubMed

    Radwan, M M; Abd El-Hamid, H K; Mohamed, A F

    2015-12-01

    The influence of using saline solution as mixing and curing liquid on some characteristics of β-dicalcium silicate (β-C2S) and biphasic compound tri-calcium phosphate/hydroxyapatite (TCP/HAp) bio-ceramics was investigated. β-C2S (27-30 nm) was prepared by solid state reaction at 1450°C, while biphasic compound TCP/HAp (7-15 nm) was synthesized from an aqueous solution of Ca(NO3)2·4H2O and (NH4)2HPO4·12H2O by chemical precipitation method. Setting times, compressive strength, pH values, X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy (SEM) were investigated. The evaluation of cytotoxicity of both calcium silicate and biphasic compounds to human gingival fibroblasts was carried out. The use of saline solution as mixing and immersing liquid shortened the setting time for the two bio-cements. TCP/HAp did not show any mechanical strength but β-C2S showed good strength values. Both synthesized compounds showed a moderate cytotoxicity and both materials were effective in a no significant way.

  11. Cytocompatibility evaluation of microwave sintered biphasic calcium phosphate scaffolds synthesized using pH control.

    PubMed

    Wagner, Darcy E; Jones, Andrew D; Zhou, Huan; Bhaduri, Sarit B

    2013-04-01

    Compounds belonging to the calcium phosphate (CaP) system are known to be major constituents of bone and are bioactive to different extents in vitro and in vivo. Their chemical similarity makes them prime candidates for implants and bone tissue engineering scaffolds. CaP nanoparticles of amorphous hydroxyapatite (aHA) and dicalcium phosphate dihydrate (DCPD) were synthesized using chemical precipitation. Uniaxially pressed aHA and DCPD powders were subjected to microwave radiation to promote solid state phase transformations resulting in crystalline hydroxyapatite (HA), tricalcium phosphate (TCP) and biphasic compositions: HA/TCP and TCP/calcium pyrophosphate (CPP) and their subsequent densification. Phase composition of microwave sintered compacts was confirmed via X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Solution pH during crystal growth was found to have a profound effect on particle morphology and post-sintered phases, despite constant sintering temperature. Cytocompatibility assessment using 7F2 cells, corresponding to adult mouse osteoblasts, on microwave and conventional, furnace sintered samples demonstrated that manufacturing method does not impact cellular viability after 24 h or proliferation over 7 days. New CaP deposition and extracellular matrix components were observed in vitro via scanning electron microscopy (SEM).

  12. Essential biphasic role for JAK3 catalytic activity in IL-2 receptor signaling.

    PubMed

    Smith, Geoffrey A; Uchida, Kenji; Weiss, Arthur; Taunton, Jack

    2016-05-01

    To drive lymphocyte proliferation and differentiation, common γ-chain (γc) cytokine receptors require hours to days of sustained stimulation. JAK1 and JAK3 kinases are found together in all γc-receptor complexes, but how their respective catalytic activities contribute to signaling over time is not known. Here we dissect the temporal requirements for JAK3 kinase activity with a selective covalent inhibitor (JAK3i). By monitoring phosphorylation of the transcription factor STAT5 over 20 h in CD4(+) T cells stimulated with interleukin 2 (IL-2), we document a second wave of signaling that is much more sensitive to JAK3i than the first wave. Selective inhibition of this second wave is sufficient to block cyclin expression and entry to S phase. An inhibitor-resistant JAK3 mutant (C905S) rescued all effects of JAK3i in isolated T cells and in mice. Our chemical genetic toolkit elucidates a biphasic requirement for JAK3 kinase activity in IL-2-driven T cell proliferation and will find broad utility in studies of γc-receptor signaling.

  13. Striatal dopamine release and biphasic pattern of locomotor and motor activity under gas narcosis.

    PubMed

    Balon, Norbert; Risso, Jean-Jacques; Blanc, François; Rostain, Jean-Claude; Weiss, Michel

    2003-05-02

    Inert gas narcosis is a neurological syndrome appearing when humans or animals are exposed to hyperbaric inert gases (nitrogen, argon) composed by motor and cognitive impairments. Inert gas narcosis induces a decrease of the dopamine release at the striatum level, structure involved in the regulation of the extrapyramidal motricity. We have investigated, in freely moving rats exposed to different narcotic conditions, the relationship between the locomotor and motor activity and the striatal dopamine release, using respectively a computerized device that enables a quantitative analysis of this behavioural disturbance and voltammetry. The use of 3 MPa of nitrogen, 2 MPa of argon and 0.1 MPa of nitrous oxide, revealed after a transient phase of hyperactivity, a lower level of the locomotor and motor activity, in relation with the decrease of the striatal dopamine release. It is concluded that the striatal dopamine decrease could be related to the decrease of the locomotor and motor hyperactivity, but that other(s) neurotransmitter(s) could be primarily involved in the behavioural motor disturbances induced by narcotics. This biphasic effect could be of major importance for future pharmacological investigations, and motor categorization, on the basic mechanisms of inert gas at pressure.

  14. A biphasic memory curve in the chambered nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea).

    PubMed

    Crook, Robyn; Basil, Jennifer

    2008-06-01

    Cephalopods are an exceptional taxon for examining the competing influences of ecology and evolutionary history on brain and behaviour. Coleoid cephalopods (octopuses, cuttlefishes and squids) have evolved specialised brains containing dedicated learning and memory centres, and rely on plastic behaviours to hunt prey effectively and communicate intricate visual displays. Their closest living relative, the primitive nautilus, is the sole remnant of an ancient lineage that has persisted since the Cambrian. Nautilus brains are the simplest among the extant cephalopods, and the absence of dedicated learning and memory regions may represent an ancestral condition. It is assumed that the absence of these regions should limit memory storage and recall in nautilus, but this assumption has never been tested. Here we describe the first evidence of learning and memory in chambered nautilus (Nautilus pompilius). Using a Pavlovian conditioning paradigm, we demonstrate that chambered nautilus exhibits temporally separated short- and long-term memory stores, producing a characteristic biphasic memory curve similar to that of cuttlefishes. Short-term memory persisted for less than 1 h post-training, whereas long-term memory was expressed between 6 and 24 h after training. Despite lacking the dedicated neural regions that support learning and memory in all other extant cephalopods, nautilus expressed a similar memory profile to coleoids. Thus the absence of these regions in the nautilus brain does not appear to limit memory expression, as hypothesised. Our results provide valuable insights into the evolution of neural structures supporting memory.

  15. Biphasic changes in body temperature produced by intracerebroventricular injections of histamine in the cat.

    PubMed

    Clark, W G; Cumby, H R

    1976-09-01

    1. Intracerebroventricular administration of histamine to cats caused hypothermia followed by a rise in body temperature. 2-Methylhistamine caused a similar biphasic response, while 3-methylhistamine had no effect on body temperature and 4-methylhistamine produced a delayed hyperthermia. Some tolerance to the hypothermic activity developed when a series of closely spaced injections of histamine was given. 2. Doses of histamine and 2-methylhistamine which altered body temperature when given centrally were ineffective when infused or injected I.V. 3. Pyrilamine, an H1-receptor antagonist, prevented the hypothermic response to histamine. 4. Hypothermic responses to histamine at an environmental temperature of 22 degrees C were comparable to responses in a cold room at 4 degrees C in both resting animals and animals acting to depress a lever to escape an external heat load. A change in error signal from the thermostat could account for these results. However, lesser degrees of hypothermia developed when histamine was given to animals in a hot environment. In some, but not all animals, this smaller response could be attributed to inadequate heat loss in spite of maximal activation of heat-loss mechanisms. 5. The hyperthermic response to histamine was antagonized by central, but not peripheral, injection of metiamide, an H2-receptor antagonist. 6. The results indicate that histamine and related agents can act centrally to cause both hypothermia, mediated by H1-receptors, and hyperthermia, mediated by H2-receptors.

  16. A flow reactor setup for photochemistry of biphasic gas/liquid reactions

    PubMed Central

    Schachtner, Josef; Bayer, Patrick

    2016-01-01

    Summary A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction). Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories. PMID:27829887

  17. Social support and positive events as suicide resiliency factors: examination of synergistic buffering effects.

    PubMed

    Kleiman, Evan M; Riskind, John H; Schaefer, Karen E

    2014-01-01

    This study examines the role of social support and positive events as protective factors in suicide. Participants (n = 379) were administered measures of social support, life events, depressive symptoms, and suicide ideation. Results indicated that (1) social support had a direct protective effect on suicide ideation, (2) social support and positive events acted as individual buffers in the relationship between negative events and suicide ideation, and (3) social support and positive events synergistically buffered the relationship between negative events and suicide ideation. Our results provide evidence that positive events and social support act as protective factors against suicide individually and synergistically when they co-occur.

  18. Effect of Positive Reinforcement on Visual Academic Performance with a Partially Sighted Child

    ERIC Educational Resources Information Center

    Swanson, H. Lee

    1977-01-01

    The effects of positive reinforcement on an 8-year-old partially sighted girl's visual academic performance were assessed, using a multiple baseline design that involved tasks of matching and of counting number sets. (Author/DLS)

  19. Effects of Positive and Negative Adult-Child Interactions on Children's Social Preference

    ERIC Educational Resources Information Center

    Redd, William H.; And Others

    1975-01-01

    Studied the effects of positive and negative interaction on the performance of preschool and elementary school children and their preferences for the adults associated with each type of interaction. (Author/SDH)

  20. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    PubMed Central

    Bragard, Jean; Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.; Fenton, Flavio H.

    2013-01-01

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one–dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 106 simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation. PMID:24387558

  1. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    NASA Astrophysics Data System (ADS)

    Bragard, Jean; Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.; Fenton, Flavio H.

    2013-12-01

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one-dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 106 simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  2. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    SciTech Connect

    Bragard, Jean Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Fenton, Flavio H.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.

    2013-12-15

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one–dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 10{sup 6} simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  3. Photoinduced biphasic hydrogen evolution: decamethylosmocene as a light-driven electron donor.

    PubMed

    Ge, Peiyu; Olaya, Astrid J; Scanlon, Micheál D; Hatay Patir, Imren; Vrubel, Heron; Girault, Hubert H

    2013-07-22

    Excitation of the weak electron donor decamethylosmocene on illumination with white light produces an excited-state species capable of reducing organically solubilized protons under biphasic conditions. Insight into the mechanism and kinetics of light-driven biphasic hydrogen evolution are obtained by analysis with gas chromatography, cyclic voltammetry, and UV/Vis and (1)H NMR spectroscopy. Formation of decamethylosmocenium hydride, which occurs prior to hydrogen evolution, is a rapid step relative to hydrogen release and takes place independently of light activation. Remarkably, hydride formation occurs with greater efficiency (ca. 90% conversion) under biphasic conditions than when the reaction is carried out in an acidified single organic phase (ca. 20% conversion). Cyclic voltammetry studies reveal that decamethylosmocene has a higher proton affinity than either decamethylferrocene or osmocene.

  4. Investigation of the feasibility of a biphase turbine for industrial process energy recovery. Final report

    SciTech Connect

    Helgeson, N.

    1985-06-28

    Tests were conducted to assess the technical applicability of the Biphase turbine to two process streams. A Biphase impulse turbine was tested on a flashing Selexol stream used for removal of CO/sub 2/ from process gases. The experimental results showed that the two-phase nozzle performance of the flashing Selexol stream was substantially below equilibrium calculation predictions. Consequently, the turbine power generated by this expanding two-phase flow was below predicted values, and was approximately equivalent to the liquid hydraulic power available. Additional gas-liquid phase separation occurred on the rotor such that overall separation efficiency reached 98% of that which occurred in the long residence time settling tank (equilibrium). The Biphase reaction turbine was tested on a flashing natural gas/crude oil stream. Nozzle, rotary and overall turbine performance were in good agreement with pre-test predictions for power generation and efficiency of operation. 141 figs., 35 tabs.

  5. Building Teacher Teams: Evidence of Positive Spillovers from More Effective Colleagues

    ERIC Educational Resources Information Center

    Sun, Min; Loeb, Susanna; Grissom, Jason A.

    2017-01-01

    Student peer effects are well documented; however, we know far less about peer effects among teachers. We hypothesize that a relatively effective teacher can positively affect the performance of his or her peers, whereas a relatively ineffective teacher may negatively affect the performance of other teachers with whom he or she works closely.…

  6. The effect of positive air ions on reproduction and growth in laboratory rats

    NASA Astrophysics Data System (ADS)

    Hinsull, S. M.; Head, E. L.

    1986-03-01

    The aim of the present investigation was to determine the growth rates, reproductive success and early mortality of laboratory rats maintained at 10,000 positive ions/ml over two generations. These findings were compared with those from animals maintained at ambient ion levels. The present work indicates that positive ions do not have any adverse effects on the reproductive capabilities or the growth of laboratory rats. In contrast it is shown that exposure to elevated levels of positive ions promotes overall growth, particularly in male rats. This action of positive ions increases with each successive generation exposed to the ions. It is suggested that the growth promoting effect of positive ions may be mediated via some modulation of the endocrine system.

  7. Citrate-Based Biphasic Scaffolds for the Repair of Large Segmental Bone Defects

    PubMed Central

    Guo, Ying; Tran, Richard T.; Xie, Denghui; Nguyen, Dianna Y.; Gerhard, Ethan; Guo, Jinshan; Wang, Yuchen; Tang, Jiajun; Zhang, Zhongming; Bai, Xiaochun; Yang, Jian

    2014-01-01

    Attempts to replicate native tissue architecture have lead to the design of biomimetic scaffolds focused on improving functionality. In this study, biomimetic citrate-based poly (octanediol citrate) – click hydroxyapatite (POC-Click-HA) scaffolds were developed to simultaneously replicate the compositional and architectural properties of native bone tissue while providing immediate structural support for large segmental defects following implantation. Biphasic scaffolds were fabricated with 70% internal phase porosity and various external phase porosities (between 5–50%) to mimic the bimodal distribution of cancellous and cortical bone, respectively. Biphasic POC-Click-HA scaffolds displayed compressive strengths up to 37.45 ± 3.83 MPa, which could be controlled through the external phase porosity. The biphasic scaffolds were also evaluated in vivo for the repair of 10-mm long segmental radial defects in rabbits and compared to scaffolds of uniform porosity as well as autologous bone grafts after 5, 10, and 15 weeks of implantation. The results showed that all POC-Click-HA scaffolds exhibited good biocompatibility and extensive osteointegration with host bone tissue. Biphasic scaffolds significantly enhanced new bone formation with higher bone densities in the initial stages after implantation. Biomechanical and histomorphometric analysis supported a similar outcome with biphasic scaffolds providing increased compression strength, interfacial bone ingrowth, and periosteal remodeling in early time points, but were comparable to all experimental groups after 15 weeks. These results confirm the ability of biphasic scaffold architectures to restore bone tissue and physiological functions in the early stages of recovery, and the potential of citrate-based biomaterials in orthopedic applications. PMID:24829094

  8. A Structurally and Functionally Biomimetic Biphasic Scaffold for Intervertebral Disc Tissue Engineering

    PubMed Central

    Choy, Andrew Tsz Hang; Chan, Barbara Pui

    2015-01-01

    Tissue engineering offers high hopes for the treatment of intervertebral disc (IVD) degeneration. Whereas scaffolds of the disc nucleus and annulus have been extensively studied, a truly biomimetic and mechanically functional biphasic scaffold using naturally occurring extracellular matrix is yet to be developed. Here, a biphasic scaffold was fabricated with collagen and glycosaminoglycans (GAGs), two of the most abundant extracellular matrix components in the IVD. Following fabrication, the scaffold was characterized and benchmarked against native disc. The biphasic scaffold was composed of a collagen-GAG co-precipitate making up the nucleus pulposus-like core, and this was encapsulated in multiple lamellae of photochemically crosslinked collagen membranes comprising the annulus fibrosus-like lamellae. On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc. The annulus-independent nature of disc height recovery suggests that the fluid replacement function of the engineered nucleus pulposus core might mimic this hitherto unique feature of native disc. Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery. However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs. This study contributes to the rationalized design and development of a biomimetic and mechanically viable biphasic scaffold for IVD tissue engineering. PMID:26115332

  9. The emergence of an unmarkedness effect in Mandarin speech errors: nasals in a coda position.

    PubMed

    Hsu, Hsiu-ling

    2011-09-01

    This study aims to explore how the markedness effect shapes Mandarin slips of the tongue with respect to nasals in syllable-final positions. Data were collected via natural speech and elicitation tasks from 35 participants' reading of 346 test items. Three hundred and eight slips in Mandarin from natural data and 360 slips from elicited data were investigated. This study shows that there exists a strong preference for unmarked coronal nasals over marked dorsal nasals in the syllable-final position in both spontaneous and elicited Mandarin slips. This tendency toward the unmarked [n] reveals that the influence of the unmarkedness effect is present in the coda position in Mandarin slips. Interestingly, this tendency is inconsistent with that found in a previous study by Wan of Mandarin slips in the onset position, which shows a tendency for coronals to be replaced by other sounds. This suggests an onset-coda distinction occurring in Mandarin speech errors, which implies that the markedness effect works differently in distinct syllable positions. More precisely, the unmarkedness effect emerges in the coda position in Mandarin slips, leading to the occurrence of unmarked segments, whereas it submerges in the onset position, resulting in marked segments.

  10. The Older Adult Positivity Effect in Evaluations of Trustworthiness: Emotion Regulation or Cognitive Capacity?

    PubMed Central

    Zebrowitz, Leslie A.; Boshyan, Jasmine; Ward, Noreen; Gutchess, Angela; Hadjikhani, Nouchine

    2017-01-01

    An older adult positivity effect, i.e., the tendency for older adults to favor positive over negative stimulus information more than do younger adults, has been previously shown in attention, memory, and evaluations. This effect has been attributed to greater emotion regulation in older adults. In the case of attention and memory, this explanation has been supported by some evidence that the older adult positivity effect is most pronounced for negative stimuli, which would motivate emotion regulation, and that it is reduced by cognitive load, which would impede emotion regulation. We investigated whether greater older adult positivity in the case of evaluative responses to faces is also enhanced for negative stimuli and attenuated by cognitive load, as an emotion regulation explanation would predict. In two studies, younger and older adults rated trustworthiness of faces that varied in valence both under low and high cognitive load, with the latter manipulated by a distracting backwards counting task. In Study 1, face valence was manipulated by attractiveness (low /disfigured faces, medium, high/fashion models’ faces). In Study 2, face valence was manipulated by trustworthiness (low, medium, high). Both studies revealed a significant older adult positivity effect. However, contrary to an emotion regulation account, this effect was not stronger for more negative faces, and cognitive load increased rather than decreased the rated trustworthiness of negatively valenced faces. Although inconsistent with emotion regulation, the latter effect is consistent with theory and research arguing that more cognitive resources are required to process negative stimuli, because they are more cognitively elaborated than positive ones. The finding that increased age and increased cognitive load both enhanced the positivity of trustworthy ratings suggests that the older adult positivity effect in evaluative ratings of faces may reflect age-related declines in cognitive capacity

  11. Comparing Versions of the Good Behavior Game: Can a Positive Spin Enhance Effectiveness?

    PubMed

    Wahl, Elaine; Hawkins, Renee O; Haydon, Todd; Marsicano, Richard; Morrison, Julie Q

    2016-07-01

    Disruptions can prevent the classroom from being an effective learning environment. The Good Behavior Game (GBG) is a group contingency that has been proven to effectively prevent disruptions and increase engagement. However, the traditional methods of the GBG include teacher scanning for negative student behaviors, and may not align with Positive Behavioral Interventions and Supports (PBIS), which is becoming widely adopted in many schools. Extending the findings of Wright and McCurdy, the current study compared the effects of the GBG and a positive version of the GBG, called the Caught Being Good Game (CBGG), on student behavior, including engagement and off-task behaviors, as well as teachers' use of positive and negative statements. Results showed both the GBG and the CBGG improved student behavior, with data not clearly indicating one was superior. Neither intervention led to an increase in positive teacher statements. Implications for teachers and suggestions for further research are discussed.

  12. Drosophila mini-white model system: new insights into positive position effects and the role of transcriptional terminators and gypsy insulator in transgene shielding

    PubMed Central

    Silicheva, Margarita; Golovnin, Anton; Pomerantseva, Ekaterina; Parshikov, Aleksander; Georgiev, Pavel; Maksimenko, Oksana

    2010-01-01

    The white gene, which is responsible for eye pigmentation, is widely used to study position effects in Drosophila. As a result of insertion of P-element vectors containing mini-white without enhancers into random chromosomal sites, flies with different eye color phenotypes appear, which is usually explained by the influence of positive/negative regulatory elements located around the insertion site. We found that, in more than 70% of cases when mini-white expression was subject to positive position effects, deletion of the white promoter had no effect on eye pigmentation; in these cases, the transposon was inserted into the transcribed regions of genes. Therefore, transcription through the mini-white gene could be responsible for high levels of its expression in most of chromosomal sites. Consistently with this conclusion, transcriptional terminators proved to be efficient in protecting mini-white expression from positive position effects. On the other hand, the best characterized Drosophila gypsy insulator was poorly effective in terminating transcription and, as a consequence, only partially protected mini-white expression from these effects. Thus, to ensure maximum protection of a transgene from position effects, a perfect boundary/insulator element should combine three activities: to block enhancers, to provide a barrier between active and repressed chromatin, and to terminate transcription. PMID:19854952

  13. Effect of sitting, standing, and supine body positions on facial soft tissue: detailed 3D analysis.

    PubMed

    Ozsoy, U; Sekerci, R; Ogut, E

    2015-10-01

    Medical imaging techniques require various body positions. Gravity causes changes in the facial soft tissue and acts in different directions according to the position of the head during imaging. The aim of this study was to evaluate the effect of positional changes on the facial soft tissue. The faces of subjects were scanned in the standing, sitting, and supine body positions. Differences in the positions were compared using the root mean square (RMS), mean absolute deviation (MAD), and mean signed distance (MSD). The displacement of 15 midsagittal and 20 bilateral landmarks was evaluated. The RMS, MAD, and MSD values of the sitting-standing comparison were significantly lower than those of the sitting-supine and standing-supine comparisons. There were no significant differences between the sitting-supine and standing-supine comparisons. Sixteen out of 135 measurements (12%) of the midsagittal landmarks and 94 out of 180 (52%) measurements of the bilateral landmarks showed significant displacements among the body positions. These results demonstrate a significant change in the facial soft tissue caused by body position. Furthermore, these data show the different susceptibilities of the facial soft tissue landmarks to the effect of body position along the x, y, and z axes.

  14. Humanizing HIV/AIDS and its (re)stigmatizing effects: HIV public 'positive' speaking in India.

    PubMed

    Finn, Mark; Sarangi, Srikant

    2009-01-01

    Social stigma has been inextricably linked with HIV and AIDS since the epidemic erupted in the early 1980s. The stigma that has built up around HIV and AIDS is generally regarded as having a negative impact on the quality of life of HIV-positive people and on general prevention efforts. Current attempts to combat HIV-related stigma focus on increasing the acceptance of HIV among the stigmatizing public and stigmatized individuals alike. In this, the global HIV-positive community is being increasingly called upon to ;humanize' the virus, not least through public displays of HIV 'positive' health and public ;positive' speaking. This article critically explores the constitutive effects and inherent power relations of HIV Positive Speakers' Bureaus (PSBs) as a platform for such a display. Adopting a post-structuralist discourse analytic approach, we explore accounts of positive-speaking and HIV health from HIV-related non-government organizations in India and in PSB training manuals. In particular, we highlight ways in which positive-speaking in India can be seen to have significant (re)stigmatizing effects by way of ambivalent and hyper-real configurations of HIV 'positive' identity and life.

  15. Situational factors affecting sleep paralysis and associated hallucinations: position and timing effects.

    PubMed

    Cheyne, J A

    2002-06-01

    Sleep paralysis (SP) entails a period of paralysis upon waking or falling asleep and is often accompanied by terrifying hallucinations. Two situational conditions for sleep paralysis, body position (supine, prone, and left or right lateral decubitus) and timing (beginning, middle, or end of sleep), were investigated in two studies involving 6730 subjects, including 4699 SP experients. A greater number of individuals reported SP in the supine position than all other positions combined. The supine position was also 3-4 times more common during SP than when normally falling asleep. The supine position during SP was reported to be more prevalent at the middle and end of sleep than at the beginning suggesting that the SP episodes at the later times might arise from brief microarousals during REM, possibly induced by apnea. Reported frequency of SP was also greater among those consistently reporting episodes at the beginning and middle of sleep than among those reporting episodes when waking up at the end of sleep. The effects of position and timing of SP on the nature of hallucinations that accompany SP were also examined. Modest effects were found for SP timing, but not body position, and the reported intensity of hallucinations and fear during SP. Thus, body position and timing of SP episodes appear to affect both the incidence and, to a lesser extent, the quality of the SP experience.

  16. Cancer: brain-regulated biphasic stress response induces cell growth or cell death to adapt to psychological stressors.

    PubMed

    Thomas, Charles; Bhatia, Shruti

    2014-01-01

    According to Indian Vedic philosophy, a human being contains 3 major bodies: (1) the matter body--brain, organs, and senses; (2) the mental body--mind, individual consciousness, intellect, and ego; and (3) the soul or causal body--universal consciousness. The third, which is located in the heart according to all spiritual traditions and recent scientific literature, can be seen as the information body that contains all memories. The mental body, which can interface with the matter and information bodies, can be seen as a field of immaterial energy that can carry, regulate, and strengthen all information (eg, thoughts or emotions) both positively and negatively. This body of information may store ancestral and/or autobiographical memories: unconscious memories from inner traumas--inner information (Ii) or samskaras in Vedic philosophy--and conscious memories from outer traumas--outer information (Io). These conscious and unconscious memories can be seen as potential psychological stressors. Resonance between Ii and Io may induce active conflicts if resistance occurs in the mental body; this conflict may cause specific metabolic activity in the brain and a stress response in the physical body, which permits adjustment to psychological stressors. The brainregulated stress response may be biphasic: cell death or growth induced by adrenergic molecular pathways during the conflict's unresolved phase and reversion to cell growth or death induced by cholinergic molecular pathways during the conflict's resolved phase. Case studies and data mining from PubMed suggest that this concept complies with the principles of holistic medicine and the scientific literature supporting its benefits. We suggest that the evolution of cancer can be seen as a biphasic stress response regulated by the brain to adapt to psychological stressors, which produce imbalance among the physical, mental, and information bodies.

  17. Are Age Effects in Positivity Influenced by the Valence of Distractors?

    PubMed

    Ziaei, Maryam; von Hippel, William; Henry, Julie D; Becker, Stefanie I

    2015-01-01

    An age-related 'positivity' effect has been identified, in which older adults show an information-processing bias towards positive emotional items in attention and memory. In the present study, we examined this positivity bias by using a novel paradigm in which emotional and neutral distractors were presented along with emotionally valenced targets. Thirty-five older and 37 younger adults were asked during encoding to attend to emotional targets paired with distractors that were either neutral or opposite in valence to the target. Pupillary responses were recorded during initial encoding as well as a later incidental recognition task. Memory and pupillary responses for negative items were not affected by the valence of distractors, suggesting that positive distractors did not automatically attract older adults' attention while they were encoding negative targets. Additionally, the pupil dilation to negative items mediated the relation between age and positivity in memory. Overall, memory and pupillary responses provide converging support for a cognitive control account of positivity effects in late adulthood and suggest a link between attentional processes and the memory positivity effect.

  18. Effects of movement from a postural maintenance position on lumbar hemodynamic changes.

    PubMed

    Kumamoto, Tsuneo; Seko, Toshiaki; Takahashi, Yui

    2016-06-01

    [Purpose] To investigate the effects of movement from a postural maintenance position on lumbar hemodynamic changes, in order to prevent lower back pain and develop exercise therapy. [Subjects and Methods] Twenty-five healthy adults (mean age: 23.2 years) participated in the study. During flexion-extension exercise, the subjects moved their trunks gradually to a flexed position from an upright posture while sitting and standing, and then returned to and maintained an upright (re-upright) position. In the extension-flexion exercise, the subjects moved their trunks gradually from an upright posture to an extended position, and back while maintaining an upright (re-upright) position. Lumbar spinal muscle activity and hemodynamic changes were evaluated during both exercises. [Results] During the flexion and extension exercises, increased trunk-flexion angle caused increased muscle activity, decreased oxygenated hemoglobin in the multifidus muscle, and increased deoxygenated hemoglobin in the multifidus and lumbar erector spinae muscles. Moreover, the muscle activities were nearly the same in the re-upright and upright positions, and total hemoglobin also increased. [Conclusion] In both standing and sitting positions, holding the trunk in a flexed position causes ischemic hemodynamic changes in the multifidus muscle; however, the hyperemic response when returning the trunk to an extended position may improve circulation.

  19. Effects of movement from a postural maintenance position on lumbar hemodynamic changes

    PubMed Central

    Kumamoto, Tsuneo; Seko, Toshiaki; Takahashi, Yui

    2016-01-01

    [Purpose] To investigate the effects of movement from a postural maintenance position on lumbar hemodynamic changes, in order to prevent lower back pain and develop exercise therapy. [Subjects and Methods] Twenty-five healthy adults (mean age: 23.2 years) participated in the study. During flexion-extension exercise, the subjects moved their trunks gradually to a flexed position from an upright posture while sitting and standing, and then returned to and maintained an upright (re-upright) position. In the extension–flexion exercise, the subjects moved their trunks gradually from an upright posture to an extended position, and back while maintaining an upright (re-upright) position. Lumbar spinal muscle activity and hemodynamic changes were evaluated during both exercises. [Results] During the flexion and extension exercises, increased trunk-flexion angle caused increased muscle activity, decreased oxygenated hemoglobin in the multifidus muscle, and increased deoxygenated hemoglobin in the multifidus and lumbar erector spinae muscles. Moreover, the muscle activities were nearly the same in the re-upright and upright positions, and total hemoglobin also increased. [Conclusion] In both standing and sitting positions, holding the trunk in a flexed position causes ischemic hemodynamic changes in the multifidus muscle; however, the hyperemic response when returning the trunk to an extended position may improve circulation. PMID:27390450

  20. Turn down the volume or change the channel? Emotional effects of detached versus positive reappraisal.

    PubMed

    Shiota, Michelle N; Levenson, Robert W

    2012-09-01

    Cognitive reappraisal, or changing one's interpretation of an event in order to alter the emotional response to it, is thought to be a healthy and an effective emotion regulation strategy. Although researchers recognize several distinct varieties of reappraisal, few studies have explicitly compared the effects of multiple reappraisal strategies on emotional responding. The present study compares the effects of detached and positive reappraisal on thought content, subjective emotional experience, physiological reactivity, and facial expressions of emotion while viewing film clips evoking sadness and disgust. Although both forms of reappraisal reduced overall emotional responding to unpleasant stimuli, the effects of detached reappraisal were stronger in this regard, and positive reappraisal was more likely to maintain subjective experience and facial expression of stimulus-appropriate positive emotions. The two reappraisal strategies also produced somewhat different profiles of physiological responding. Differences between detached and positive reappraisal with respect to subjective experience and facial expression were more pronounced among men than women; the reverse was true for differences with respect to physiological responding. Beyond these effects on individual emotion response systems, detached and positive reappraisal also had somewhat different effects on coherence in change across response systems. Implications for our understanding of emotion regulation processes, and for emotion theory more broadly, are discussed.

  1. Contrasting effects of hemiparasites on ecosystem processes: can positive litter effects offset the negative effects of parasitism?

    PubMed Central

    Suding, Katharine N.

    2010-01-01

    Hemiparasites are known to influence community structure and ecosystem functioning, but the underlying mechanisms are not well studied. Variation in the impacts of hemiparasites on diversity and production could be due to the difference in the relative strength of two interacting pathways: direct negative effects of parasitism and positive effects on N availability via litter. Strong effects of parasitism should result in substantial changes in diversity and declines in productivity. Conversely, strong litter effects should result in minor changes in diversity and increased productivity. We conducted field-based surveys to determine the association of Castillejaoccidentalis with diversity and productivity in the alpine tundra. To examine litter effects, we compared the decomposition of Castilleja litter with litter of four other abundant plant species, and examined the decomposition of those four species when mixed with Castilleja. Castilleja was associated with minor changes in diversity but almost a twofold increase in productivity and greater foliar N in co-occurring species. Our decomposition trials suggest litter effects are due to both the rapid N loss of Castilleja litter and the effects of mixing Castilleja litter with co-occurring species. Castilleja produces litter that accelerates decomposition in the alpine tundra, which could accelerate the slow N cycle and boost productivity. We speculate that these positive effects of litter outweigh the effects of parasitism in nutrient-poor systems with long-lived hemiparasites. Determining the relative importance of parasitism and litter effects of this functional group is crucial to understand the strong but variable roles hemiparasites play in affecting community structure and ecosystem processes. PMID:20658151

  2. Domain identification moderates the effect of positive stereotypes on Chinese American women's math performance.

    PubMed

    Saad, Carmel S; Meyer, Oanh L; Dhindsa, Manveen; Zane, Nolan

    2015-01-01

    We examined whether an individual difference factor, math domain identification, moderated performance following positive stereotype activation. We hypothesized that positive stereotype activation would improve performance for those more math identified (compared to a control condition), but would hinder performance for those less math identified. We examined 116 Chinese American women (mean age = 19 years). Participants were assigned to the positive stereotype activation condition or to the control condition before completing a math test. Positive stereotype activation led more math identified participants to perform significantly better than the control condition, whereas it led less math identified participants to perform significantly worse than the control condition. Domain identification moderates the effect of positive stereotype activation. Educators should consider how testing situations are constructed, especially when test takers do not identify highly with the domain.

  3. Suppressor Effects of Positive and Negative Religious Coping on Academic Burnout Among Korean Middle School Students.

    PubMed

    Noh, Hyunkyung; Chang, Eunbi; Jang, Yoojin; Lee, Ji Hae; Lee, Sang Min

    2016-02-01

    Statistical suppressor effects in prediction models can provide evidence of the interdependent relationship of independent variables. In this study, the suppressor effects of positive and negative religious coping on academic burnout were examined using longitudinal data. First, 388 middle school students reported their type of religion and use of positive and negative religious coping strategies. Four months later, they also reported their level of academic burnout. From structural equation modeling, significant suppressor effects were found among religious students. That is, the coefficients became larger when both positive and negative religious coping predicted academic burnout simultaneously, compared to when each religious coping predicted academic burnout alone. However, suppressor effects were not found among non-religious students.

  4. The Effects of Schoolwide Positive Behavior Supports in an Elementary School

    ERIC Educational Resources Information Center

    Gleason, Ann-Marie

    2012-01-01

    The purpose of this study was to evaluate the effects of Schoolwide Positive Behavior Supports (SWPBS) in an elementary school within a large, urban school district located in the South. The effects of first year implementation of the SWPBS program were studied by examining Office Disciplinary Referrals (ODRs) and academic achievement data in…

  5. Effects of Kinesio taping on joint position sense of the ankle

    PubMed Central

    Seo, Hyun-Do; Kim, Min-Young; Choi, Jung-Eun; Lim, Ga-Hee; Jung, Seong-In; Park, So-Hyun; Cheon, Song-Hee; Lee, Hae-Yong

    2016-01-01

    [Purpose] The purpose of this study was to examine the effect of Kinesio taping on the joint position sense of the ankle. [Subjects and Methods] The subjects of this study were 26 nomal adults who had experienced ankle sprain. Kinesio taping was applied over the ankle medial ligament and ankle lateral ligament with eight pattern reinforcement taping. Joint position sense was measured using isokinetic equipment (Biodex System 4 pro dynamometer, Biodex Medical systems Inc., USA) during dorsiflexion/plantarflexion and inversion/eversion, before and after taping. Statistical analyses were performed using SPSS 21.0 for Windows. [Results] Joint position sense after Kinesio taping was improved in the dorsiflexion and inversion positions. [Conclusion] According to the results of this study, Kinesio taping of the ankle is effective for the prevention of ankle sprain. PMID:27190446

  6. Rethinking emotion: cognitive reappraisal is an effective positive and negative emotion regulation strategy in bipolar disorder.

    PubMed

    Gruber, June; Hay, Aleena C; Gross, James J

    2014-04-01

    Bipolar disorder involves difficulties with emotion regulation, yet the precise nature of these emotion regulatory difficulties is unclear. The current study examined whether individuals with remitted bipolar I disorder (n = 23) and healthy controls (n = 23) differ in their ability to use one effective and common form of emotion regulation, cognitive reappraisal. Positive, negative, and neutral films were used to elicit emotion, and participants were cued to watch the film carefully (i.e., uninstructed condition) or reappraise while measures of affect, behavior, and psychophysiology were obtained. Results showed that reappraisal was associated with reductions in emotion reactivity across subjective (i.e., positive and negative affect), behavioral (i.e., positive facial displays), and physiological (i.e., skin conductance) response domains across all participants. Results suggest that reappraisal may be an effective regulation strategy for both negative and positive emotion across both healthy adults and individuals with bipolar disorder. Discussion focuses on clinical and treatment implications for bipolar disorder.

  7. Dynamic Effects of Anchor Positional Tolerance on Tension Moored Floating Wind Turbine

    NASA Astrophysics Data System (ADS)

    Wright, Christopher; Pakrashi, Vikram; Murphy, Jimmy

    2016-09-01

    For water depths greater than 60m floating wind turbines will become the most economical option for generating offshore wind energy. Tension mooring stabilised units are one type of platform being considered by the offshore wind energy industry. The complex mooring arrangement used by this type of platform means that the dynamics are greatly effected by offsets in the positioning of the anchors. This paper examines the issue of tendon anchor position tolerances. The dynamic effects of three positional tolerances are analysed in survival state using the time domain FASTLink. The severe impact of worst case anchor positional offsets on platform and turbine survivability is shown. The worst anchor misposition combinations are highlighted and should be strongly avoided. Novel methods to mitigate this issue are presented.

  8. Analysis of the effect of swimmer's head position on swimming performance using computational fluid dynamics.

    PubMed

    Zaïdi, H; Taïar, R; Fohanno, S; Polidori, G

    2008-01-01

    The aim of this numerical work is to analyze the effect of the position of the swimmer's head on the hydrodynamic performances in swimming. In this initial study, the problem was modeled as 2D and in steady hydrodynamic state. The geometry is generated by the CAD software CATIA and the numerical simulation is carried out by the use of the CFD Fluent code. The standard k-epsilon turbulence model is used with a specific wall law. Three positions of the head were studied, for a range of Reynolds numbers about 10(6). The obtained numerical results revealed that the position of the head had a noticeable effect on the hydrodynamic performances, strongly modifying the wake around the swimmer. The analysis of these results made it possible to propose an optimal position of the head of a swimmer in underwater swimming.

  9. Effect of body position on vocal tract acoustics: Acoustic pharyngometry and vowel formants.

    PubMed

    Vorperian, Houri K; Kurtzweil, Sara L; Fourakis, Marios; Kent, Ray D; Tillman, Katelyn K; Austin, Diane

    2015-08-01

    The anatomic basis and articulatory features of speech production are often studied with imaging studies that are typically acquired in the supine body position. It is important to determine if changes in body orientation to the gravitational field alter vocal tract dimensions and speech acoustics. The purpose of this study was to assess the effect of body position (upright versus supine) on (1) oral and pharyngeal measurements derived from acoustic pharyngometry and (2) acoustic measurements of fundamental frequency (F0) and the first four formant frequencies (F1-F4) for the quadrilateral point vowels. Data were obtained for 27 male and female participants, aged 17 to 35 yrs. Acoustic pharyngometry showed a statistically significant effect of body position on volumetric measurements, with smaller values in the supine than upright position, but no changes in length measurements. Acoustic analyses of vowels showed significantly larger values in the supine than upright position for the variables of F0, F3, and the Euclidean distance from the centroid to each corner vowel in the F1-F2-F3 space. Changes in body position affected measurements of vocal tract volume but not length. Body position also affected the aforementioned acoustic variables, but the main vowel formants were preserved.

  10. Effect of body position on vocal tract acoustics: Acoustic pharyngometry and vowel formants

    PubMed Central

    Vorperian, Houri K.; Kurtzweil, Sara L.; Fourakis, Marios; Kent, Ray D.; Tillman, Katelyn K.; Austin, Diane

    2015-01-01

    The anatomic basis and articulatory features of speech production are often studied with imaging studies that are typically acquired in the supine body position. It is important to determine if changes in body orientation to the gravitational field alter vocal tract dimensions and speech acoustics. The purpose of this study was to assess the effect of body position (upright versus supine) on (1) oral and pharyngeal measurements derived from acoustic pharyngometry and (2) acoustic measurements of fundamental frequency (F0) and the first four formant frequencies (F1–F4) for the quadrilateral point vowels. Data were obtained for 27 male and female participants, aged 17 to 35 yrs. Acoustic pharyngometry showed a statistically significant effect of body position on volumetric measurements, with smaller values in the supine than upright position, but no changes in length measurements. Acoustic analyses of vowels showed significantly larger values in the supine than upright position for the variables of F0, F3, and the Euclidean distance from the centroid to each corner vowel in the F1-F2-F3 space. Changes in body position affected measurements of vocal tract volume but not length. Body position also affected the aforementioned acoustic variables, but the main vowel formants were preserved. PMID:26328699

  11. The first letter position effect in visual word recognition: The role of spatial attention.

    PubMed

    Aschenbrenner, Andrew J; Balota, David A; Weigand, Alexandra J; Scaltritti, Michele; Besner, Derek

    2017-04-01

    A prominent question in visual word recognition is whether letters within a word are processed in parallel or in a left to right sequence. Although most contemporary models posit parallel processing, this notion seems at odds with well-established serial position effects in word identification that indicate preferential processing for the initial letter. The present study reports 4 experiments designed to further probe the locus of the first position processing advantage. The paradigm involved masked target words presented for short durations and required participants to subsequently select from 2 alternatives, 1 which was identical to the target and 1 that differed by a single letter. Experiment 1 manipulated the case between the target and the alternatives to ensure that previous evidence for a first position effect was not due to simple perceptual matching. The results continued to yield a robust first position advantage. Experiment 2 attempted to eliminate postperceptual decision processes as the explanatory mechanism by presenting single letters as targets and requiring participants to select an entire word that contained the target letter at different positions. Here the first position advantage was eliminated, suggesting postperceptual decision processes do not underlie the effect. The final 2 experiments presented masked stimuli either all vertically (Experiment 3) or randomly intermixed vertical and horizontal orientation (Experiment 4). In both cases, a robust first position advantage was still obtained. The authors consider alternative interpretations of this effect and suggest that these results are consistent with a rapid deployment of spatial attention to the beginning of a target string which occurs poststimulus onset. (PsycINFO Database Record

  12. Angular and positional dependence of Purcell effect for layered metal-dielectric structures

    NASA Astrophysics Data System (ADS)

    Gubaydullin, A. R.; Mazlin, V. A.; Ivanov, K. A.; Kaliteevski, M. A.; Balocco, C.

    2016-04-01

    We study the angular dependence of the spontaneous emission enhancement of a dipole source inserted into a layered metal-dielectric metamaterial. We analyse the dependence of Purcell effect from the position of the dipole in the layered hyperbolic media. We analyse the impact of the complex structure of eigenmodes of the system operating in hyperbolic regime. We have shown that the spontaneous emission rate of the dipole emitter depends on its position, which mainly affect the interaction with Langmuir modes.

  13. Effect of collision parameters in electronegative plasma sheath with two species of positive ions

    SciTech Connect

    Moulick, R.; Goswami, K. S.; Mahanta, M. K.

    2013-09-15

    The effect of ion neutral collision is shown for two species of positive ions in electronegative plasma. The ion neutral collision is modeled using power law of collision cross section. It is a usual case for processing plasma to have two species of positive ions and hence we attempt to study the dynamics of the two species of ions inside the collisional sheath of electronegative plasma.

  14. Effects of box handle position and carrying range on bi-manual carrying capacity for females.

    PubMed

    Wu, Swei-Pi; Loiu, Yi; Chien, Te Hong

    2015-01-01

    This study utilizes a psychophysical approach to examine the effects on carrying capacity for bi-manual carrying tasks involving different handle positions and carrying ranges. A total of 16 female subjects participated in the experiment in groups of two people, and each group of subjects performed the tasks in a random order with 12 different combinations of carrying task. The independent variables are handle position (upper, middle, lower) and carrying range (F-F: floor height carried to floor height, F-W: floor height carried to waist height, W-W: waist height carried to waist height, W-F: waist height carried to floor height), the dependent variable is the maximum acceptable carried weight (MAWC), heart rate (HR), and the rating of perceived exertion (RPE). The results show that the handle position has a significant effect on MAWC and overall RPE but no significant effect on HR. Carrying range has a significant effect on the MAWC and HR, but no significant effect on overall HR. The handle position and carrying range have a significant interaction on the MAWC and HR. The RPE for different body parts shows significant differences, and the hands feel the most tired. Overall, this study confirms that the lower handle position with the W-W carrying range is the best combination for a two-person carrying task.

  15. Age and positional effect on the anterior chamber angle: assessment by ultrasound biomicroscopy.

    PubMed

    Bell, Nicholas P; Nagi, Kundandeep S; Cumba, Ricardo J; Chuang, Alice Z; Lee, David A; Prager, Thomas C; Rao, Kavita; Feldman, Robert M

    2013-01-01

    Purpose. To investigate age- and position-related changes of anterior chamber angle anatomy in normal, healthy eyes. Patients and Methods. Thirty subjects were separated into a younger and older cohort. The superior and inferior anterior chamber angles of the eyes were measured in supine and sitting positions by ultrasound biomicroscopy (UBM) with bag/balloon technology. Statistical analysis was used to evaluate positional and age-related changes in angle morphology. Results. In the younger cohort, no location or positional differences in angle anatomy were observed. In the older cohort, the inferior quadrant was significantly narrower than the superior quadrant (P = 0.0186) in the supine position. This cohort also demonstrated an interaction effect between position and location. In the older cohort, the angle was deeper inferiorly while the subject was sitting but was deeper superiorly while the subject was supine. Conclusion. Comparison of positional variations in anterior chamber angle anatomy as measured by UBM has recently become possible. This study found that age-related positional changes in the anterior chamber angle anatomy exist in normal healthy eyes.

  16. The Effects of a Valgus Collapse Knee Position on In Vivo ACL Elongation

    PubMed Central

    Utturkar, G. M.; Irribarra, L. A.; Taylor, K. A.; Spritzer, C. E.; Taylor, D. C.; Garrett, W. E.; DeFrate, Louis E.

    2013-01-01

    There are conflicting data regarding what motions increase ACL injury risk. More specifically, the mechanical role of valgus collapse positions during ACL injury remains controversial. Our objective was to evaluate ACL elongation in a model that mimics knee movements thought to occur during ACL injury. Eight healthy male subjects were imaged using MR and biplanar fluoroscopy to measure the in vivo elongation of the ACL and its functional bundles during three static knee positions: full extension, 30° of flexion, and a position intended to mimic a valgus collapse position described in the literature. For this study, the valgus collapse position consisted of 30° of knee flexion, internal rotation of the hip, and 10° of external tibial rotation. ACL length decreased significantly from full extension (30.2 ± 2.6 mm) to 30° of flexion (27.1 ± 2.2 mm). ACL length further decreased in the valgus collapse position (25.6 ± 2.4 mm). Both functional bundles of the ACL followed similar trends with regards to decreases in length in each of the three positions. Since strain would follow patterns of ACL length, landing on an extended knee may be a more relevant risk factor for ACL injuries than the valgus collapse position in males. Future studies should evaluate the effects of dynamic motion patterns on in vivo ACL strains. PMID:22855117

  17. The effects of a valgus collapse knee position on in vivo ACL elongation.

    PubMed

    Utturkar, G M; Irribarra, L A; Taylor, K A; Spritzer, C E; Taylor, D C; Garrett, W E; Defrate, Louis E

    2013-01-01

    There are conflicting data regarding what motions increase ACL injury risk. More specifically, the mechanical role of valgus collapse positions during ACL injury remains controversial. Our objective was to evaluate ACL elongation in a model that mimics knee movements thought to occur during ACL injury. Eight healthy male subjects were imaged using MR and biplanar fluoroscopy to measure the in vivo elongation of the ACL and its functional bundles during three static knee positions: full extension, 30° of flexion, and a position intended to mimic a valgus collapse position described in the literature. For this study, the valgus collapse position consisted of 30° of knee flexion, internal rotation of the hip, and 10° of external tibial rotation. ACL length decreased significantly from full extension (30.2 ± 2.6 mm) to 30° of flexion (27.1 ± 2.2 mm). ACL length further decreased in the valgus collapse position (25.6 ± 2.4 mm). Both functional bundles of the ACL followed similar trends with regards to decreases in length in each of the three positions. Since strain would follow patterns of ACL length, landing on an extended knee may be a more relevant risk factor for ACL injuries than the valgus collapse position in males. Future studies should evaluate the effects of dynamic motion patterns on in vivo ACL strains.

  18. Metabolomics Reveals Metabolic Targets and Biphasic Responses in Breast Cancer Cells Treated by Curcumin Alone and in Association with Docetaxel

    PubMed Central

    2013-01-01

    Background Curcumin (CUR) has deserved extensive research due to its anti-inflammatory properties, of interest in human diseases including cancer. However, pleiotropic even paradoxical responses of tumor cells have been reported, and the mechanisms of action of CUR remain uncompletely elucidated. Methodology/Principal Findings 1H-NMR spectroscopy-based metabolomics was applied to get novel insight into responses of MCF7 and MDA-MB-231 breast cancer cells to CUR alone, and MCF7 cells to CUR in cotreatment with docetaxel (DTX). In both cell types, a major target of CUR was glutathione metabolism. Total glutathione (GSx) increased at low dose CUR (≤ 10 mg.l−1–28 µM-) (up to +121% in MCF7 cells, P<0.01, and +138% in MDA-MB-231 cells, P<0.01), but decreased at high dose (≥ 25 mg.l−1 −70 µM-) (−49%, in MCF7 cells, P<0.02, and −56% in MDA-MB-231 cells, P<0.025). At high dose, in both cell types, GSx-related metabolites decreased, including homocystein, creatine and taurine (−60 to −80%, all, P<0.05). Together with glutathione-S-transferase actvity, data established that GSx biosynthesis was upregulated at low dose, and GSx consumption activated at high dose. Another major target, in both cell types, was lipid metabolism involving, at high doses, accumulation of polyunsaturated and total free fatty acids (between ×4.5 and ×11, P<0.025), and decrease of glycerophospho-ethanolamine and -choline (about −60%, P<0.025). Multivariate statistical analyses showed a metabolic transition, even a biphasic behavior of some metabolites including GSx, between low and high doses. In addition, CUR at 10 mg.l−1 in cotreatment with DTX induced modifications in glutathione metabolism, lipid metabolism, and glucose utilization. Some of these changes were biphasic depending on the duration of exposure to CUR. Conclusions/Significance Metabolomics reveals major metabolic targets of CUR in breast cancer cells, and biphasic responses that challenge the widely accepted

  19. Amplification of a bi-phase shift-key modulated signal by a mm-wave FEL

    SciTech Connect

    Prosnitz, D.; Scharlemann, E.T.; Sheaffer, M.K.

    1991-10-01

    Bi-phase shift keying (BPSK) is a modulation scheme used in communications and radar in which the phase of a transmitted rf signal is switched in a coded pattern between discrete values differing by {pi} radians. The transmitted information rate (in communications) or resolution (in imaging radar) depends on the rate at which the transmitted signal can be modulated. Modulation rates of greater than 1 GHz are generally desired. Although the instantaneous gain bandwidth of a mm-wave FEL amplifier can be much greater than 10 GHz, slippage may limit the BPSK modulation rate that can be amplified. Qualitative slippage arguments would limit the modulation rate to relatively low values; nevertheless, simulations with a time-dependent FEL code (GINGER) indicate that rates of 2 GHz or more are amplified without much loss in modulation integrity. In this paper we describe the effects of slippage in the simulations and discuss the limits of simple arguments.

  20. Amplification of a bi-phase shift-key modulated signal by a mm-wave FEL

    NASA Astrophysics Data System (ADS)

    Prosnitz, D.; Scharlemann, E. T.; Sheaffer, M. K.

    1991-10-01

    Bi-phase shift keying (BPSK) is a modulation scheme used in communications and radar in which the phase of a transmitted RF signal is switched in a coded pattern between discrete values differing by (pi) radians. The transmitted information rate (in communications) or resolution (in imaging radar) depends on the rate at which the transmitted signal can be modulated. Modulation rates of greater than 1 GHz are generally desired. Although the instantaneous gain bandwidth of a mm-wave FEL amplifier can be much greater than 10 GHz, slippage may limit the BPSK modulation rate that can be amplified. Qualitative slippage arguments would limit the modulation rate to relatively low values; nevertheless, simulations with a time-dependent FEL code (GINGER) indicate that rates of 2 GHz or more are amplified without much loss in modulation integrity. In this paper we describe the effects of slippage in the simulations and discuss the limits of simple arguments.

  1. Amplification of a bi-phase shift-key modulated signal by a mm-wave FEL

    NASA Astrophysics Data System (ADS)

    Prosnitz, D.; Scharlemann, E. T.; Sheaffer, M. K.

    1992-07-01

    Bi-phase shift keying (BPSK) is a modulation scheme used in communications and radar in which the phase of a transmitted rf signal is switched in a coded pattern between discrete values differing by π radians. The transmitted information rate (in communications) or resolution (in imaging radar) depends on the rate at which the transmitted signal can be modulated. Modulation rates of greater than 1 GHz are generally desired. Although the instantaneous gain bandwidth of a mm-wave FEL amplifier can be much greater than 10 GHz, slippage may limit the BPSK modulation rate that can be amplified. Qualitative slippage arguments would limit the modulation rate to relatively low values; nevertheless, simulations with a time-dependent FEL code (GINGER) indicate that rates of 2 GHz or more are amplified without much loss in modulation integrity. In this paper we describe the effects of slippage in the simulations and discuss the limits of simple slippage arguments.

  2. Predicting adolescent substance use: the effects of depressed mood and positive expectancies.

    PubMed

    Clark, Heddy Kovach; Ringwalt, Chris L; Shamblen, Stephen R

    2011-05-01

    This study examined whether sixth-graders' depressed mood and positive substance use expectancies predicted increases over the next two years in students' lifetime and 30-day cigarette, alcohol, and marijuana use, and whether sixth graders' positive substance use expectancies moderated the relationship between baseline depressed mood and changes over the next two years in the use of these substances. Study data came from a randomized controlled trial of Project ALERT, a school-based substance use prevention program, in which students from 34 schools completed self-report surveys as sixth (n=5782), seventh (n=5065), and eighth graders (n=4940). Primary analyses were performed using Hierarchical Nonlinear Modeling. Over time, there were significant effects of baseline positive expectancies on each of the six measures of substance use. Baseline depressed mood predicted increases over time only for lifetime use of cigarettes and alcohol, and for 30-day alcohol use. Positive expectancies significantly moderated the effects of adolescent depressed mood only on lifetime marijuana use. Although depressed mood predicted substance use for half of our variables, our results suggest that positive expectancies are a more consistent predictor of adolescent substance use, and that they may moderate the effects of depressed mood on marijuana, but not cigarette or alcohol, use. Substance use prevention programs may benefit from addressing adolescents' perceptions about the positive consequences of drug use.

  3. Computational predictors fail to identify amino acid substitution effects at rheostat positions

    PubMed Central

    Miller, M.; Bromberg, Y.; Swint-Kruse, L.

    2017-01-01

    Many computational approaches exist for predicting the effects of amino acid substitutions. Here, we considered whether the protein sequence position class – rheostat or toggle – affects these predictions. The classes are defined as follows: experimentally evaluated effects of amino acid substitutions at toggle positions are binary, while rheostat positions show progressive changes. For substitutions in the LacI protein, all evaluated methods failed two key expectations: toggle neutrals were incorrectly predicted as more non-neutral than rheostat non-neutrals, while toggle and rheostat neutrals were incorrectly predicted to be different. However, toggle non-neutrals were distinct from rheostat neutrals. Since many toggle positions are conserved, and most rheostats are not, predictors appear to annotate position conservation better than mutational effect. This finding can explain the well-known observation that predictors assign disproportionate weight to conservation, as well as the field’s inability to improve predictor performance. Thus, building reliable predictors requires distinguishing between rheostat and toggle positions. PMID:28134345

  4. Are Age Effects in Positivity Influenced by the Valence of Distractors?

    PubMed Central

    Ziaei, Maryam; von Hippel, William; Henry, Julie D.; Becker, Stefanie I.

    2015-01-01

    An age-related ‘positivity’ effect has been identified, in which older adults show an information-processing bias towards positive emotional items in attention and memory. In the present study, we examined this positivity bias by using a novel paradigm in which emotional and neutral distractors were presented along with emotionally valenced targets. Thirty-five older and 37 younger adults were asked during encoding to attend to emotional targets paired with distractors that were either neutral or opposite in valence to the target. Pupillary responses were recorded during initial encoding as well as a later incidental recognition task. Memory and pupillary responses for negative items were not affected by the valence of distractors, suggesting that positive distractors did not automatically attract older adults’ attention while they were encoding negative targets. Additionally, the pupil dilation to negative items mediated the relation between age and positivity in memory. Overall, memory and pupillary responses provide converging support for a cognitive control account of positivity effects in late adulthood and suggest a link between attentional processes and the memory positivity effect. PMID:26366872

  5. Serial-Position Effects on a Free-Recall Task in Bilinguals

    PubMed Central

    Yoo, Jeewon; Kaushanskaya, Margarita

    2015-01-01

    In this study, we examined mechanisms that underlie free-recall performance in bilinguals’ first language (L1) and second language (L2) through the prism of serial-position effects. On free-recall tasks, a typical pattern of performance follows a U-shaped serial-position curve, where items from the beginning of the list (the primacy effect) and items from the end of the list (the recency effect) are recalled with higher accuracy than items from the middle of the list. The present study contrasted serial-position effects on the free-recall task in Korean-English bilinguals’ L1 vs. L2 and examined the relationship between an independent working memory (WM) measure and serial-position effects in bilinguals’ two languages. Results revealed stronger pre-recency (primacy and middle) effects in L1 than in L2, but similar recency effects in the two languages. A close association was observed between WM and recall performance in the pre-recency region in the L1 but not in the L2. Together, these findings suggest that linguistic knowledge constrains free-recall performance in bilinguals, but only in the pre-recency region. PMID:25730660

  6. Strontium substituted calcium phosphate biphasic ceramics obtained by a powder precipitation method.

    PubMed

    Kim, Hae-Won; Koh, Young-Hag; Kong, Young-Min; Kang, Jun-Gu; Kim, Hyoun-Ee

    2004-10-01

    Strontium (Sr) substituted calcium phosphate ceramics were fabricated using a powder precipitation method. The Sr ions were added up to 8 mol % to replace the Ca ions during the powder preparation. Composition analysis showed that the added Sr was not fully incorporated within the as-precipitated apatite structure, presumably being washed out during the powder preparation. After calcination, the Sr containing powders were crystallized into apatite and tricalcium phosphate (TCP), that is, biphasic calcium phosphates were formed. The amount of TCP increased with increasing the Sr addition. The lattice parameters of the calcined powders increased gradually with Sr substitution in both the a- and c-axis. However, the obtained values deviated slightly from the calculated ones at higher Sr additions (>4%) due to the partial substitution of Sr ions. The microstructure of the sintered bodies changed with the Sr addition due to the formation of TCP. The Vickers hardness increased slightly from 5.2 to 5.5 MPa with increasing Sr addition, which was driven by the HA+TCP biphasic formation. The osteoblast-like cells cultured on the Sr-substituted biphasic sample spread and grew actively. The proliferation rate of the cells was higher in the samples containing more Sr. The alkaline phosphate activity of the cells was expressed to a higher degree with increasing Sr addition. These observations confirmed the enhanced cell viability and differentiation of the Sr-substituted biphasic calcium phosphate ceramics.

  7. Modeling Biphasic Environmental Decay of Pathogens and Implications for Risk Analysis.

    PubMed

    Brouwer, Andrew F; Eisenberg, Marisa C; Remais, Justin V; Collender, Philip A; Meza, Rafael; Eisenberg, Joseph N S

    2017-02-21

    As the appreciation for the importance of the environment in infectious disease transmission has grown, so too has interest in pathogen fate and transport. Fate has been traditionally described by simple exponential decay, but there is increasing recognition that some pathogens demonstrate a biphasic pattern of decay-fast followed by slow. While many have attributed this behavior to population heterogeneity, we demonstrate that biphasic dynamics can arise through a number of plausible mechanisms. We examine the identifiability of a general model encompassing three such mechanisms: population heterogeneity, hardening off, and the existence of viable-but-not-culturable states. Although the models are not fully identifiable from longitudinal sampling studies of pathogen concentrations, we use a differential algebra approach to determine identifiable parameter combinations. Through case studies using Cryptosporidium and Escherichia coli, we show that failure to consider biphasic pathogen dynamics can lead to substantial under- or overestimation of disease risks and pathogen concentrations, depending on the context. More reliable models for environmental hazards and human health risks are possible with an improved understanding of the conditions in which biphasic die-off is expected. Understanding the mechanisms of pathogen decay will ultimately enhance our control efforts to mitigate exposure to environmental contamination.

  8. Cell surface energy, contact angles and phase partition. II. Bacterial cells in biphasic aqueous mixtures.

    PubMed

    Gerson, D F; Akit, J

    1980-11-04

    Partition coefficients in biphasic mixtures of poly(ethylene glycol) and Dextran are compared to cell surface energies obtained from contact angles of each liquid phase on cell layers. Linear relationships are observed between these two independent measurements for a variety of bacterial cells. The results demonstrate the importance of interfacial phenomena and contact angles in the phase-partition process.

  9. Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration.

    PubMed

    Son, Jun-Sik; Kim, Su-Gwan; Oh, Ji-Su; Appleford, Mark; Oh, Sunho; Ong, Joo L; Lee, Kyu-Bok

    2011-12-15

    This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material.

  10. Selection of Xenobiotic-Degrading Microorganisms in a Biphasic Aqueous-Organic System

    PubMed Central

    Ascon-Cabrera, Miguel; Lebeault, Jean-Michel

    1993-01-01

    Microbial selection on mixtures of chlorinated and nonchlorinated compounds that are poorly soluble in water and/or toxic to growing microbial cells was examined in both biphasic aqueous-organic and monophasic aqueous systems. A biphasic system in which silicone oil was used as the organic phase permitted the acceleration of acclimation, leading to rapid selection and to an increase in xenobiotic compound degradation. In contrast, acclimation, selection, and degradation were very slow in the monophasic aqueous system. The variation in microbial growth rate with the degree of dispersion (i.e., dispersion at different silicone oil concentrations and agitation rates), and cell adhesion to the silicone oil indicate that the performance of the biphasic aqueous-organic system is dependent on the interfacial area between the two phases and that microbial activity is important at this interface. Therefore, the biphasic water-silicone oil system could be used for microbial selection in the presence of xenobiotic compounds that are toxic and have low water solubility. PMID:16348949

  11. Comparison the effect of Sleep Positioning on Cardiorespiratory Rate in Noninvasive Ventilated Premature Infants

    PubMed Central

    Ghorbani, Fatemeh; Asadollahi, Maliheh; Valizadeh, Sousan

    2013-01-01

    Background: Results of several studies suggest that prone position is beneficial in improving the preterm infants’ cardio-respiratory status. Previous studies showed opposite results, and also there is not any available clear study about the effect of this position on cardio-respiratory rates of Nasal Continuous Positive Airway Pressure (N-CPAP) treating premature infants. Objectives: This study aimed at comparing supine and prone positions on cardio-respiratory rates of premature infants with respiratory distress syndrome (RDS) who were treated using N-CPAP. Patients and Methods: This was a cross over study which was performed in 2010 on 44 hospitalized 29-34 weeks gestation premature infants who were receiving N-CPAP in Neonatal Intensive Care Unit of Al-Zahra Hospital of Tabriz University of Medical Sciences. Infants were randomly assigned into two groups, and the first group was placed in prone at first and then in supine, and the position of second group was at first supine and then prone. Infants’ Heart Rate (HR) and Respiratory Rate (RR) were assessed three times in each position for 30 minutes. The data was recorded in a data-collection form, and demographic data was analyzed using t test, Chi square and Fisher exact test. Also, repeated measurement ANOVA and Tukey post-hoc tests were used. Results: There was a significant difference in HR and RR of premature infants who were similar in gestational age and clinical condition and placed in two positions. Premature infants’ HR and RR became lower at prone position than supine in both groups. So it can be concluded that prone position could decrease infants HR and RR, but supine position might increase them (P < 0.05). Conclusion: Our findings support prone positioning for premature infants. Therefore, it is advisable to NICU staff that if there is no obstacle for changing the infant’s position, prone position in infants with respiratory complications during receiving N-CPAP in NICU can be useful

  12. Effects of Herceptin on circulating tumor cells in HER2 positive early breast cancer.

    PubMed

    Zhang, J-L; Yao, Q; Chen Y Wang, J-H; Wang, H; Fan, Q; Ling, R; Yi, J; Wang, L

    2015-03-20

    The objective of this study was to determine the changes in peripheral blood circulating tumor cells in HER2-positive early breast cancer before and after Herceptin therapy, and to explore the effects of the HER2 gene and Herceptin on circulating tumor cells. CK19 mRNA expression in peripheral blood was evaluated by qRT-PCR as an index of circulating tumor cells in 15 cases of HER-2-positive breast cancer and 18 cases of HER2-negative breast cancer before, and after chemotherapy as well. Ten cases of HER2-positive breast cancer continued on Herceptin therapy for 3 months after chemotherapy, and their peripheral blood was again drawn and assayed for CK-19 mRNA expression. Preoperatively, all cases of HER2-positive cancer were positive for CK19 mRNA in peripheral blood, but 6 cases of HER2-negative breast cancer were positive (33.3%), where there was a substantial difference between the two groups. After 6 cycles of adjuvant chemotherapy, CK19 positive rates in cases of HER2-positive and -negative breast cancer reduced by 93.3 and 11.1%, respectively, with a significant difference still existing. After 3 months of Herceptin therapy, expression of CK19 mRNA declined considerably in 10 cases of HER2 positive breast cancer (113.66 ± 88.65 vs 63.35 ± 49.27, P = 0.025). HER-2 gene expression closely correlated with circulating tumor cells in peripheral blood of early breast cancer patients. Moreover, Herceptin, a monoclonal antibody for HER2, can reduce the number of circulating tumor cells, which can be an early predictive factor for Herceptin therapy effectiveness against breast cancer.

  13. Establishment of a new animal model of allergic rhinitis with biphasic sneezing by intranasal sensitization with Staphylococcal enterotoxin B.

    PubMed

    Sun, Rong; Tang, Xinye; Yao, Hongbing; Hong, Suling; Yang, Yang; Kou, Wei; Wei, Ping

    2015-08-01

    Allergic rhinitis (AR) is a global health problem. The effectiveness of currently available medications is limited and therefore investigation for more effective drugs is essential. The aim of the present study was to establish a model of AR in guinea pigs that can be utilized for the further investigation of new drugs. Guinea pigs were intranasally sensitized with 1 µg Staphylococcal enterotoxin B (SEB) dissolved in 40 µl saline once daily for 14 days. One week after the last sensitization, the same treatment was applied intranasally once every four days for a total of 30 times. In the treatment group, terfenadine was administered orally 70 min before the 4th, 14th and 24th challenge. Sneezing and nasal scratching were evaluated following each of the 30 challenges. The quantity of antigen-specific antibodies in the serum was measured. Between the 19th and 30th challenges, the guinea pigs in the model group produced significant biphasic elevations in sneezing number, with peaks 10 min-2 h and 4-8 h after the SEB challenges. In addition, the guinea pigs produced significantly more sneezing in the first peak during the 19th to 30th challenges than during the first to 18th challenges (P<0.01). Terfenadine significantly inhibited the early- and late-phase sneezing at all challenge times. The serum levels of SEB-specific immunoglobulin (Ig) E and IgG1 were higher in the model group in comparison with those in the control group (P<0.01). This experiment demonstrated that SEB can induce typical AR with biphasic sneezing in guinea pigs. Histamine may play an important role in the early- and the late-phase sneezing in the model of AR. This model can be potentially used for the investigation of new drugs.

  14. Positive inotropic effect of Murraya koenigii (Linn.) Spreng extract on an isolated perfused frog heart.

    PubMed

    Shah, Kunal J; Juvekar, Archana R

    2006-06-01

    Ethanolic extract of fresh leaves of M. koenigii (MKEE) showed a dose dependent positive inotropic effect on isolated frog heart. The responses to MKEE (62.5-1000 microg) were not affected in either way by theophylline, imidazole, propranolol and sildenafil. The change in potassium and sodium concentration did not alter MKEE-induced positive inotropic effect. Lignocaine did not alter the responses to MKEE significantly. Responses to MKEE were significantly inhibited when calcium concentration was reduced to half (from 1.58 to 0.79 mM) and were significantly potentiated when calcium concentration was doubled (from 1.58 to 3.16 mM). Verapamil was found to inhibit the responses significantly. The results suggest that M. koenigii induced positive inotropic effect possibly by increasing availability of calcium from extra cellular sites.

  15. Heterochromatic Position Effect at the Rosy Locus of DROSOPHILA MELANOGASTER: Cytological, Genetic and Biochemical Characterization

    PubMed Central

    Rushlow, C. A.; Chovnick, A.

    1984-01-01

    This report describes cytological, genetic and biochemical studies designed to characterize two γ-radiation induced, apparent "underproducer" variants of the rosy locus (ry:3-52.0), ryps1149 and ryps11136. The following observations provide a compelling basis for their diagnosis as heterochromatic position effect variants. (1) They are associated with rearrangements that place heterochromatin adjacent to the rosy region of chromosome 3 (87D). (2) The effect of these mutations on rosy locus expression is subject to modification by abnormal Y chromosome content. (3) The rearrangement alters only the expression of the rosy allele on the same chromosome (cis-acting). (4) The Y chromosome modification is only on the position-affected allele's expression. (5) The recessive lethality associated with the rearrangements relate to specific rosy region vital loci, and for ryps 11136, the lethality is not Y chromosome modified. (6) The peptide product of the position-affected allele is qualitatively normal by several criteria. (7) Heterozygous deletion of 87E2-F2 is a suppressor of the rosy position effect. (8) The rosy position effect on XDH production may be assayed in whole larvae and larval fat body tissue as well as in adults. PMID:6437902

  16. An investigation on piezoresistive behavior of carbon nanotube/polymer composites: II. Positive piezoresistive effect

    NASA Astrophysics Data System (ADS)

    Wang, Zhifeng; Ye, Xiongying

    2014-07-01

    Due to the diversity of carbon nanotubes (CNTs), polymers, and the preparation processes of the composites, CNT-filled polymeric composites present various piezoresistive properties. One puzzling issue is the concurrence of a negative piezoresistive effect and a positive piezoresistive effect in composites with different polymer matrixes. In this paper, we present a microscopic view of the nature of the positive piezoresistive effect and its dependence on the polymer matrix types based on the model in our previous study, in which the piezoresistive behavior was tailored by a parameter—the average junction gap variation (AJGV)—describing the statistical property of the CNT conductive network. The microscopic movement process of CNTs embedded in a polymer matrix was analyzed and then the Poisson’s ratio of the polymer matrix was determined as a key factor that is in charge of negative or positive piezoresistive properties. The obstacle effect of polymer chains on the movement of CNTs was also found to be responsible for the positive piezoresistive effect as it affects the AJGV in compressive strain. Based on numerical simulations of CNT network deformation with different Poisson’s ratios and minimum junction gaps caused by the obstacle effect, the positive piezoresistive effect was found resulted from the obstacle effect on CNT junction gap variations that exceeds the initial value of the AJGV caused by the CNT network deformation, and only occur under the precondition of the polymer matrixes with a large Poisson’s ratio close to 0.5. The conclusions were then verified experimentally using composites with two kinds of polymer matrixes with significantly different Poisson’s ratios.

  17. Are positive and negative reinforcement "different"? Insights from a free-operant differential outcomes effect.

    PubMed

    Magoon, Michael A; Critchfield, Thomas S; Merrill, Dustin; Newland, M Christopher; Schneider, W Joel

    2017-01-01

    Although theoretical discussions typically assume that positive and negative reinforcement differ, the literature contains little unambiguous evidence that they produce differential behavioral effects. To test whether the two types of consequences control behavior differently, we pitted money-gain positive reinforcement and money-loss-avoidance negative reinforcement, scheduled through identically programmed variable-cycle schedules, against each other in concurrent schedules. Contingencies of response-produced feedback, normally different in positive and negative reinforcement, were made symmetrical. Steeper matching slopes were produced compared to a baseline consisting of all positive reinforcement. This free-operant differential outcomes effect supports the notion that that stimulus-presentation positive reinforcement and stimulus-elimination negative reinforcement are functionally "different." However, a control experiment showed that the feedback asymmetry of more traditional positive and negative reinforcement schedules also is sufficient to create a "difference" when the type of consequence is held constant. We offer these findings as a small step in meeting the very large challenge of moving negative reinforcement theory beyond decades of relative quiescence.

  18. Positivity effect in healthy aging in observational but not active feedback-learning.

    PubMed

    Bellebaum, Christian; Rustemeier, Martina; Daum, Irene

    2012-01-01

    The present study investigated the impact of healthy aging on the bias to learn from positive or negative performance feedback in observational and active feedback learning. In active learning, a previous study had already shown a negative learning bias in healthy seniors older than 75 years, while no bias was found for younger seniors. However, healthy aging is accompanied by a 'positivity effect', a tendency to primarily attend to stimuli with positive valence. Based on recent findings of dissociable neural mechanisms in active and observational feedback learning, the positivity effect was hypothesized to influence older participants' observational feedback learning in particular. In two separate experiments, groups of young (mean age 27) and older participants (mean age 60 years) completed an observational or active learning task designed to differentially assess positive and negative learning. Older but not younger observational learners showed a significant bias to learn better from positive than negative feedback. In accordance with previous findings, no bias was found for active learning. This pattern of results is discussed in terms of differences in the neural underpinnings of active and observational learning from performance feedback.

  19. The Effects of Cadaver Orientation on the Relative Position of the Abdominal Organs

    PubMed Central

    Howes, Meghan K.; Hardy, Warren N.; Beillas, Philippe

    2013-01-01

    Biplane x-ray was used to image two cadavers in upright and inverted postures, and the three-dimensional variation in the relative abdominal organ position was quantified. The abdominal organs of each surrogate were instrumented with radiopaque markers using a minimally invasive approach. Imaging was performed with a known stomach volume, with residual air removed from the abdominal cavity, and with ventilation and perfusion. Marker positions were determined in two planar x-ray perspectives using target tracking software and projected into calibrated three-dimensional coordinates. Intuitive changes in organ position were observed with the effect of gravity in the upright orientation; in the superior-inferior direction, the separation between the most cranial and caudal diaphragm and liver markers was 95 mm to 169 mm. When inverted, the abdominal organs shifted cranially and fell within 66 to 81 mm in the superior-inferior direction. The relative change in position of the diaphragm markers, determined as the vector magnitude from the upright to the inverted position, was 99 to 121 mm. These data were scaled and compared to positional MRI data from nine human subjects in seated postures and the Global Human Body Models Consortium (GHBMC) model geometry. The overall shapes and relative positions of the inverted cadaver organs compared better to the human subjects and model geometry. These results give rise to several issues for consideration when interpreting cadaver test results and comparing them to finite element simulations and their associated injury prediction abilities. PMID:24406959

  20. Effects of upper extremity training in a standing position on trunk alignment in stroke patients

    PubMed Central

    Kim, Eun Ja; Lee, Kyoung Bo; Hwang, Byong Yong

    2016-01-01

    [Purpose] This study aimed to examine the effect of upper extremity training in the standing position on trunk alignment of patients with stroke. [Subjects and Methods] Twelve stroke patients were enrolled in the study and divided into two groups: a group of six patients in a sitting position and a group of six patients in a standing position. Upper extremity training for 30 min per day, five times a week for six weeks was given to subjects in both groups. In order to assess trunk alignment, lumbar lordosis and thoracic kyphosis were examined before and after upper extremity training using Formetric 4D. [Results] After training the standing position group had no significant change in lumbar lordosis but a significant change in thoracic kyphosis. The sitting position group showed no significant changes in either lumbar lordosis or thoracic kyphosis. The comparison between groups showed there was no significant difference in the change in lumbar lordosis but there was a significant difference in the change in thoracic kyphosis. [Conclusion] Examination of trunk alignment showed that upper extremity training conducted in a standing position reduced thoracic kyphosis more than in a sitting position. PMID:27799662

  1. The spatial Stroop effect: a comparison of color-word and position-word interference.

    PubMed

    Hilbert, Sven; Nakagawa, Tristan Toyo; Bindl, Manuela; Bühner, Markus

    2014-12-01

    The Stroop effect is one of the most famous examples of interference in human perception. The present study demonstrates that a position Stroop paradigm, comparable to the classical color-word interference paradigm, resulted in the same pattern of interference for the spatial dimension; however, the interference was significantly weaker. By exchanging the original oral response for a manual response in the spatial paradigm, we showed that the verbal component is crucial for the Stroop effect: Manual responses lead to a disappearance of the interference effect. Moreover, with manual responses word position was recognized at the same speed for the baseline condition and for words that were incongruent as well as congruent with the spatial position. The results indicate (1) that the Stoop effect depends heavily on verbal components and (2) that differing processing speeds between reading and position recognition do not serve as a proper explanation for the effect. In addition, the provided paradigm plausibly transfers the classical color-word interference to the spatial dimension.

  2. Biphasic role of dopamine on female sexual behaviour via D2 receptors in the mediobasal hypothalamus.

    PubMed

    Fabre-Nys, Claude; Chesneau, Didier; de la Riva, Carlos; Hinton, Michael R; Locatelli, Alain; Ohkura, Satoshi; Kendrick, Keith M

    2003-03-01

    Dopamine has been implicated in the control of sexual behaviour, but its role seems quite complex and controversial. The aim of the present experiments was to investigate the effects of dopamine (DA) acting on D2 receptors in the mediobasal hypothalamus (MBH) on sexual behaviour in female sheep. To achieve this, the D2 agonist, quinpirole, was administered bilaterally via microdialysis probes into the MBH of ovariectomized ewes either before or after oestradiol (E2) administration. Quinpirole (100 ng/ml) infused for 6 h just before E2 hastened the onset of oestrus behaviour and the luteinizing hormone surge, whereas the same treatment given 6-12 h or 18-21 h after E2 decreased the intensity of sexual receptivity without affecting LH or prolactin secretion. We then tested the hypothesis that E2 stimulates the onset of oestrus partly by decreasing DA activation of D2 receptors. In this case the D2 antagonists pimozide or spiperone (100 ng/ml) were infused into the MBH via microdialysis probes for 11 h in the absence of E2 administration. A significant number of ewes showed induction of receptivity with both antagonists, although its intensity was significantly lower than that induced by E2. These treatments generally did not significantly alter extracellular concentrations of monoamines or aminoacids although quinpirole modulated the ability of sexual interactions to increase noradrenaline release. These experiments show that DA acts via D2 receptors in the MBH to control female sexual behaviour in a biphasic manner: the onset of sexual motivation and receptivity requiring an initial increase in activation followed by a decrease. This dual action could explain some of the controversies concerning DA action on sexual behaviour.

  3. FK506 induces biphasic Ca2+ release from microsomal vesicles of rat pancreatic acinar cells.

    PubMed

    Ozawa, Terutaka

    2006-07-01

    The effect of the immunosuppressant drug FK506 on microsomal Ca2+ release was investigated in rat pancreatic acinar cells. When FK506 (0.1-200 microM) was added to the microsomal vesicles at a steady state of ATP-dependent 45Ca2+ uptake, FK506 caused a dose-dependent and a biphasic release of 45Ca2+. Almost 10% of total 45Ca2+ uptake was released at FK506 concentrations up to 10 microM (Km=0.47 microM), and 60% of total 45Ca2+ uptake was released at FK506 concentrations over 10 microM (Km=55 microM). Preincubation of the vesicles with cyclic ADP-ribose (cADPR, 0.5 microM) increased the FK506 (< or =10 microM)-induced 45Ca2+ release (Ozawa T, Biochim Biophys Acta 1693: 159-166, 2004). Preincubation with heparin (200 microg/ml) resulted in significant inhibition of the FK506 (30 microM)-induced 45Ca2+ release. Subsequent addition of inositol 1,4,5-trisphosphate (IP3, 5 microM) after FK506 (100 microM)-induced 45Ca2+ release did not cause any release of 45Ca2+. These results indicate that two types of FK506-induced Ca2+ release mechanism operate in the endoplasmic reticulum of rat pancreatic acinar cells: a high-affinity mechanism of Ca2+ release, which involves activation of the ryanodine receptor, and a low-affinity mechanism of Ca2+ release, which involves activation of the IP3 receptor.

  4. Biphasic cholinergic synaptic transmission controls action potential activity in thalamic reticular nucleus neurons.

    PubMed

    Sun, Yan-Gang; Pita-Almenar, Juan D; Wu, Chia-Shan; Renger, John J; Uebele, Victor N; Lu, Hui-Chen; Beierlein, Michael

    2013-01-30

    Cholinergic neurons in the basal forebrain and the brainstem form extensive projections to a number of thalamic nuclei. Activation of cholinergic afferents during distinct behavioral states can regulate neuronal firing, transmitter release at glutamatergic and GABAergic synapses, and synchrony in thalamic networks, thereby controlling the flow of sensory information. These effects are thought to be mediated by slow and persistent increases in extracellular ACh levels, resulting in the modulation of populations of thalamic neurons over large temporal and spatial scales. However, the synaptic mechanisms underlying cholinergic signaling in the thalamus are not well understood. Here, we demonstrate highly reliable cholinergic transmission in the mouse thalamic reticular nucleus (TRN), a brain structure essential for sensory processing, arousal, and attention. We find that ACh release evoked by low-frequency stimulation leads to biphasic excitatory-inhibitory (E-I) postsynaptic responses, mediated by the activation of postsynaptic α4β2 nicotinic ACh receptors (nAChRs) and M2 muscarinic ACh receptors (mAChRs), respectively. In addition, ACh can bind to mAChRs expressed near cholinergic release sites, resulting in autoinhibition of release. We show that the activation of postsynaptic nAChRs by transmitter release from only a small number of individual axons is sufficient to trigger action potentials in TRN neurons. Furthermore, short trains of cholinergic synaptic inputs can powerfully entrain ongoing TRN neuronal activity. Our study demonstrates fast and precise synaptic E-I signaling mediated by ACh, suggesting novel computational mechanisms for the cholinergic control of neuronal activity in thalamic circuits.

  5. Is There a Paradox of Aging: When the Negative Aging Stereotype Meets the Positivity Effect in Older Adults.

    PubMed

    Zhou, Liqing; Lu, Jia; Chen, Guopeng; Dong, Li; Yao, Yujia

    2017-01-01

    Background/Study Context: Socioemotional selectivity theory (SST) states that the positivity effect is a result of older adults' emotion regulation and that older adults derive more emotional satisfaction from prioritizing positive information processing. The authors explored whether the positivity effect appeared when the negative aging stereotype was activated in older adults and also whether the effect differed between mixed and unmixed valence conditions.

  6. Facile preparation of biphasic-induced magnetic icariin-loaded composite microcapsules by automated in situ click technology.

    PubMed

    Pan, Panpan; Chen, Jingdi; Fan, Tiantang; Hu, Yimin; Wu, Tao; Zhang, Qiqing

    2016-04-01

    This research aims to prepare the biphasic-induced magnetic composite microcapsules (BIMCM) as a promising environmental stimuli-responsive delivery vehicle to dispose the problem of drug burst effect. The paper presented a novel automated in situ click technology of magnetic chitosan/nano hydroxyapatite (CS/nHA) microcapsules. Fe3O4 magnetic nanoparticles (MNP) and nHA were simultaneously in situ crystallized by one-step process. Icariin (ICA), a plant-derived flavonol glycoside, was combined to study drug release properties of BIMCM. BIMCM were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Thermal gravimetric analysis/Differential Scanning Calorimetry(TGA/DSC) in order to reveal their component and surface morphology as well as the role of the in situ generated Fe3O4 MNP and nHA. The magnetic test showed the BIMCM were super-paramagnetic. Both in situ generated Fe3O4 MNP and nHA serve as stable inorganic crosslinkers in BIMCM to form many intermolecular crosslinkages for the movability of the CS chains. This makes ICA loaded microcapsules take on a sustained release behavior and results in the self-adjusting of surface morphology, decreasing of swelling and degradation rates. In addition, in vitro tests were systematically carried out to examine the biocompatibility of the microcapsules by MTT test, Wright-Giemsa dying assay and AO/EB fluorescent staining method. These results demonstrated that successful introduction of the in situ click Fe3O4 MNP provided an alternative strategy because of magnetic sensitivity and sustained release. As such, the novel ICA loaded biphasic-induced magnetic CS/nHA/MNP microcapsules are expected to find potential applications in drug delivery system for bone repair.

  7. High-throughput bone and cartilage micropellet manufacture, followed by assembly of micropellets into biphasic osteochondral tissue.

    PubMed

    Babur, Betul Kul; Futrega, Kathryn; Lott, William B; Klein, Travis Jacob; Cooper-White, Justin; Doran, Michael Robert

    2015-09-01

    Engineered biphasic osteochondral tissues may have utility in cartilage defect repair. As bone-marrow-derived mesenchymal stem/stromal cells (MSC) have the capacity to make both bone-like and cartilage-like tissues, they are an ideal cell population for use in the manufacture of osteochondral tissues. Effective differentiation of MSC to bone-like and cartilage-like tissues requires two unique medium formulations and this presents a challenge both in achieving initial MSC differentiation and in maintaining tissue stability when the unified osteochondral tissue is subsequently cultured in a single medium formulation. In this proof-of-principle study, we used an in-house fabricated microwell platform to manufacture thousands of micropellets formed from 166 MSC each. We then characterized the development of bone-like and cartilage-like tissue formation in the micropellets maintained for 8-14 days in sequential combinations of osteogenic or chondrogenic induction medium. When bone-like or cartilage-like micropellets were induced for only 8 days, they displayed significant phenotypic changes when the osteogenic or chondrogenic induction medium, respectively, was swapped. Based on these data, we developed an extended 14-day protocol for the pre-culture of bone-like and cartilage-like micropellets in their respective induction medium. Unified osteochondral tissues were formed by layering 12,000 osteogenic micropellets and 12,000 chondrogenic micropellets into a biphasic structure and then further culture in chondrogenic induction medium. The assembled tissue was cultured for a further 8 days and characterized via histology. The micropellets had amalgamated into a continuous structure with distinctive bone-like and cartilage-like regions. This proof-of-concept study demonstrates the feasibility of micropellet assembly for the formation of osteochondral-like tissues for possible use in osteochondral defect repair.

  8. A characterization of the effect of limb position on EMG features to guide the development of effective prosthetic control schemes.

    PubMed

    Radmand, A; Scheme, E; Englehart, K

    2014-01-01

    Electromyogram (EMG) pattern recognition has long been used for the control of upper limb prostheses. More recently, it has been shown that variability induced during functional use, such as changes in limb position and dynamic contractions, can have a substantial impact on the robustness of EMG pattern recognition. This work further investigates the reasons for pattern recognition performance degradation due to the limb position variation. The main focus is on the impact of limb position variation on features of the EMG, as measured using separability and repeatability metrics. The results show that when the limb is moved to a position different from the one in which the classifier is trained, both the separability and repeatability of the data decrease. It is shown how two previously proposed classification methods, multiple position training and dual-stage classification, resolve the position effect problem to some extent through increasing either separability or repeatability but not both. A hybrid classification method which exhibits a compromise between separability and repeatability is proposed in this work. It is shown that, when tested with the limb in 16 different positions, this method increases classification accuracy from an average of 70% (single position training) to 89% (hybrid approach). This hybrid method significantly (p<;0.05) outperforms multiple position training (an average of 86%) and dual-stage classification (an average of 85%).

  9. Effect of reactor's positions on polymerization and degradation in an ultrasonic field.

    PubMed

    Kobayashi, Daisuke; Matsumoto, Hideyuki; Kuroda, Chiaki

    2008-03-01

    Ultrasonic generators are used as emulsifiers and efficient alternative initiators in polymerization processes. In this study, the effects of reactor's position on the emulsion polymerization of styrene under indirect ultrasonic irradiation were investigated, along with the effects of reactor's position on chemical and physical degradation. Both polymer yield and molecular weight were influenced by the position of the reactor. The ultrasonic irradiation could be divided into three stages, and the molecular weight of the polymer was influenced by polymerization and degradation processes. It was found that the extent of radical generation estimated by KI oxidation dosimetry and the shock wave index obtained from studies of degradation of standard polymer were useful for controlling the characteristics of the polymer generated.

  10. Effects of body position on the ventilatory response following an impulse exercise in humans.

    PubMed

    Haouzi, Philippe; Chenuel, Bruno; Chalon, Bernard

    2002-04-01

    The aim of this study was to identify some of the mechanisms that could be involved in blunted ventilatory response (VE) to exercise in the supine (S) position. The contribution of the recruitment of different muscle groups, the activity of the cardiac mechanoreceptors, the level of arterial baroreceptor stimulation, and the hemodynamic effects of gravity on the exercising muscles was analyzed during upright (U) and S exercise. Delayed rise in VE and pulmonary gas exchange following an impulselike change in work rate (supramaximal leg cycling at 240 W for 12 s) was measured in seven healthy subjects and six heart transplant patients both in U and S positions. This approach allows study of the relationship between the rise in VE and O2 uptake (VO2) without the confounding effects of contractions of different muscle groups. These responses were compared with those triggered by an impulselike change in work rate produced by the arms, which were positioned at the same level as the heart in S and U positions to separate effects of gravity on postexercising muscles from those on the rest of the body. Despite superimposable VO2 and CO2 output responses, the delayed VE response after leg exercise was significantly lower in the S posture than in the U position for each control subject and cardiac-transplant patient (-2.58 +/- 0.44 l and -3.52 +/- 1.11 l/min, respectively). In contrast, when impulse exercise was performed with the arms, reduction of ventilatory response in the S posture reached, at best, one-third of the deficit after leg exercise and was always associated with a reduction in VO2 of a similar magnitude. We concluded that reduction in VE response to exercise in the S position is independent of the types (groups) of muscles recruited and is not critically dependent on afferent signals originating from the heart but seems to rely on some of the effects of gravity on postexercising muscles.

  11. The interventional effects of loving-kindness meditation on positive emotions and interpersonal interactions.

    PubMed

    He, Xiaoli; Shi, Wendian; Han, Xiangxiang; Wang, Nana; Zhang, Ni; Wang, Xiaoli

    2015-01-01

    The study aimed to investigate the effects of loving-kindness meditation on positive emotions, intragroup interactions, and complex understanding of others. A total of 50 freshmen not receiving any training in meditation intervention were randomly divided into the meditation group (25 subjects) and the control group (25 subjects). The meditation group was implemented with group meditation intervention for 4 weeks, three times a week, about 30 minutes each time. The results revealed that the effect sizes in interpersonal interaction and complex understanding of others in the meditation group were both above 0.8, indicating strong effects. It was concluded that loving-kindness meditation can effectively improve positive emotions, interpersonal interactions, and complex understanding of others in college students.

  12. The interventional effects of loving-kindness meditation on positive emotions and interpersonal interactions

    PubMed Central

    He, Xiaoli; Shi, Wendian; Han, Xiangxiang; Wang, Nana; Zhang, Ni; Wang, Xiaoli

    2015-01-01

    The study aimed to investigate the effects of loving-kindness meditation on positive emotions, intragroup interactions, and complex understanding of others. A total of 50 freshmen not receiving any training in meditation intervention were randomly divided into the meditation group (25 subjects) and the control group (25 subjects). The meditation group was implemented with group meditation intervention for 4 weeks, three times a week, about 30 minutes each time. The results revealed that the effect sizes in interpersonal interaction and complex understanding of others in the meditation group were both above 0.8, indicating strong effects. It was concluded that loving-kindness meditation can effectively improve positive emotions, interpersonal interactions, and complex understanding of others in college students. PMID:26060402

  13. Effects of Modality and Pace on Achievement, Mental Effort, and Positive Affect in Multimedia Learning Environments

    ERIC Educational Resources Information Center

    Izmirli, Serkan; Kurt, Adile Askim

    2016-01-01

    The purpose of the study was to examine the effects of instruction given with different multimedia modalities (written text + animation or narration + animation) on the academic achievement, cognitive load, and positive affect in different paces (learner-paced or system-paced); 97 freshmen university students divided into four groups taught in…

  14. Using the Effective Behavior Supports Survey to Guide Development of Schoolwide Positive Behavior Support

    ERIC Educational Resources Information Center

    Safran, Stephen P.

    2006-01-01

    As the use of school-based positive behavior support (PBS) spreads nationwide, the development of assessment strategies to identify intervention priorities becomes more critical. This study addresses the validity of the Effective Behavior Supports Survey (Lewis & Sugai, 1999) by examining reliability, determining whether rating differences…

  15. The Emergence of an Unmarkedness Effect in Mandarin Speech Errors: Nasals in a Coda Position

    ERIC Educational Resources Information Center

    Hsu, Hsiu-ling

    2011-01-01

    This study aims to explore how the markedness effect shapes Mandarin slips of the tongue with respect to nasals in syllable-final positions. Data were collected via natural speech and elicitation tasks from 35 participants' reading of 346 test items. Three hundred and eight slips in Mandarin from natural data and 360 slips from elicited data were…

  16. Effective Instruction Delivery and Time-In: Positive Procedures for Achieving Child Compliance.

    ERIC Educational Resources Information Center

    Mandal, Rebecca L.; Olmi, D. Joe; Edwards, Ron P.; Tingstrom, Daniel H.; Benoit, Denise A.

    2000-01-01

    Preschool children (N=4) from a university-based school psychology clinic were studied to assess whether increases in compliance could be obtained in clinical settings by using only positive procedures such as effective instruction delivery and time-in. Both procedures alone achieved increases in compliance over baseline levels, and additional…

  17. The Effect of Anatomic Factors on Tongue Position Variability during Consonants

    ERIC Educational Resources Information Center

    Rudy, Krista; Yunusova, Yana

    2013-01-01

    Purpose: This study sought to investigate the effect of palate morphology and anthropometric measures of the head on positional variability of the tongue during consonants. Method: An electromagnetic tracking system was used to record tongue movements of 21 adults. Each talker produced a series of symmetrical VCV syllables containing one of the…

  18. Examining the Effect of Positive Behaviour Support on Academic Achievement of Students with Disabilities

    ERIC Educational Resources Information Center

    Chitiyo, Morgan; Makweche-Chitiyo, Plaxedes; Park, Meungguk; Ametepee, Lawrence K.; Chitiyo, Jonathan

    2011-01-01

    Students who engage in challenging behaviour compromise the fundamental ability of schools to educate children. Consequently, teachers face the daunting task of designing effective strategies to promote positive educational outcomes for their students. Since the 1997 Individuals with Disabilities Education Act amendments, the use of positive…

  19. Direct and Collateral Effects of Positive Reinforcement, Response Cost, and Mixed Contingencies for Academic Performance

    ERIC Educational Resources Information Center

    Broughton, Sam F.; Lahey, Benjamin B.

    1978-01-01

    The relative effects of positive reinforcement, response cost, and the two contingencies combined when used as contingencies for correct academic responses were compared on the dependent measures of accuracy of academic performance and level of on-task behavior. All three contingency systems increased academic performance and on-task behavior.…

  20. Recognition Time for Letters and Nonletters: Effects of Serial Position, Array Size, and Processing Order.

    ERIC Educational Resources Information Center

    Mason, Mildred

    1982-01-01

    Three experiments report additional evidence that it is a mistake to account for all interletter effects solely in terms of sensory variables. These experiments attest to the importance of structural variables such as retina location, array size, and ordinal position. (Author/PN)

  1. Effect of Items Direction (Positive or Negative) on the Reliability in Likert Scale. Paper-11

    ERIC Educational Resources Information Center

    Gul, Showkeen Bilal Ahmad; Qasem, Mamun Ali Naji; Bhat, Mehraj Ahmad

    2015-01-01

    In this paper an attempt was made to analyze the effect of items direction (positive or negative) on the Alpha Cronbach reliability coefficient and the Split Half reliability coefficient in Likert scale. The descriptive survey research method was used for the study and sample of 510 undergraduate students were selected by used random sampling…

  2. Spotlight on the positive effects of the ladybird Harmonia axyridis on agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the midst of considerable negativity surrounding the ladybird Harmonia axyridis (Pallas), this paper sheds some light on the positive effects that this predator has had on agriculture. Using resources available at the USDA, National Agricultural Library (DigiTop literature database, Navigator pla...

  3. Effects of Parent-Child Relationship on the Primary School Children's Non-Violence Position Formation

    ERIC Educational Resources Information Center

    Valeeva, Roza A.; Kalimullin, Aydar M.

    2016-01-01

    The aim of the research was to identify and test experimentally the impact of parent-child relationship on the formation of the primary school children non-violence position. During the research the effectiveness of the correctional and development program "Together with my mom" was verified to promote parent-child interaction, as well…

  4. The Effects of Different Drawing Materials on Children's Drawings of Positive and Negative Human Figures

    ERIC Educational Resources Information Center

    Burkitt, Esther; Barrett, Martyn

    2011-01-01

    Children tend to use certain drawing strategies differentially when asked to draw topics with positive and negative emotional characterisations. These effects have however only been established when children are asked to use standard drawing materials. The present study was designed to investigate whether the above pattern of children's response…

  5. Effects of Positive Affect on Risk Perceptions in Adolescence and Young Adulthood

    ERIC Educational Resources Information Center

    Haase, Claudia M.; Silbereisen, Rainer K.

    2011-01-01

    Affective influences may play a key role in adolescent risk taking, but have rarely been studied. Using an audiovisual method of affect induction, two experimental studies examined the effect of positive affect on risk perceptions in adolescence and young adulthood. Outcomes were risk perceptions regarding drinking alcohol, smoking a cigarette,…

  6. Positive Side Effects of a Job-Related Training Program for Older Adults in South Korea

    ERIC Educational Resources Information Center

    Lee, Minhong; Choi, Jae-Sung

    2012-01-01

    The objective of the current study was to evaluate empirically positive side effects of a job-related training program on older adults' self-esteem, depression, and social networks. A total of 70 older adults participated in the study after completing the Older Paraprofessional Training Program developed and provided by the Continuing Education…

  7. The Effect of Positive Peer Reinforcement on Psychological Measures and Guitar Songleading Performance in University Students

    ERIC Educational Resources Information Center

    Silverman, Michael J.

    2009-01-01

    The purpose of this study is to determine the effects of positive peer reinforcement on self-reported psychological measures and songleading performance in beginning guitar students. No differences were found between the control group (n = 21) and the experimental group (n = 20) concerning psychological measures of self-esteem, stress, and…

  8. An Extension of the Effects of Praising Positive Qualifying Autoclitics on the Frequency of Reading

    ERIC Educational Resources Information Center

    Sheyab, Mahmoud; Pritchard, Josh; Malady, Mark

    2014-01-01

    In the current study, we reinforced tacts with positive qualifying autoclitics for reading and evaluated the subsequent effect on the allocation of reading behavior. Participants were four typically developing children between 9 and 12 years of age whose primary language was Arabic. We exposed each participant to pre- and posttreatment sessions to…

  9. Analytic Study of the Tadoma Method: Effects on Hand Position of Segmental Speech Perception.

    ERIC Educational Resources Information Center

    Reed, Charlotte M.; And Others

    1989-01-01

    Small-set segmental identification experiments were conducted with three deaf-blind subjects who were highly experienced users of the Tadoma method. Systematic variations in the positioning of the hand on the speaker's face for Tadoma produced systematic effects on percent-correct scores, information transfer, and perception of individual…

  10. Negative Feedback and Positive Evidence in Task-Based Interaction: Differential Effects on L2 Development

    ERIC Educational Resources Information Center

    Iwashita, Noriko

    2003-01-01

    This study examines the role of task-based conversation in second language (L2) grammatical development, focusing on the short-term effects of both negative feedback and positive evidence on the acquisition of two Japanese structures. The data are drawn from 55 L2 learners of Japanese at a beginning level of proficiency in an Australian tertiary…

  11. Prediction of positive food effect: Bioavailability enhancement of BCS class II drugs.

    PubMed

    Raman, Siddarth; Polli, James E

    2016-06-15

    High-throughput screening methods have increased the number of poorly water-soluble, highly permeable drug candidates. Many of these candidates have increased bioavailability when administered with food (i.e., exhibit a positive food effect). Food is known to impact drug bioavailability through a variety of mechanisms, including drug solubilization and prolonged gastric residence time. In vitro dissolution media that aim to mimic in vivo gastrointestinal (GI) conditions have been developed to lessen the need for fed human bioequivalence studies. The objective of this work was to develop an in vitro lipolysis model to predict positive food effect of three BCS Class II drugs (i.e., danazol, amiodarone and ivermectin) in previously developed lipolysis media. This in vitro lipolysis model was comparatively benchmarked against FeSSIF and FaSSIF media that were modified for an in vitro lipolysis approach, as FeSSIF and FaSSIF are widely used in in vitro dissolution studies. The in vitro lipolysis model accurately predicted the in vivo positive food effect for three model BCS class II drugs. The in vitro lipolysis model has potential use as a screening test of drug candidates in early development to assess positive food effect.

  12. Comparison of the Frequency and Effectiveness of Positive and Negative Reinforcement Practices in Schools

    ERIC Educational Resources Information Center

    Dad, Hukam; Ali, Riasat; Janjua, Muhammad Zaigham Qadeer; Shahzad, Saqib; Khan, Muhammad Saeed

    2010-01-01

    The major purpose of the study was to compare the frequency and effectiveness of positive and negative reinforcement practices deployed by teachers in boys' and girls' secondary schools in urban and rural areas. It was hypothesized that there would be no difference in use of reward and punishment by teachers in secondary schools in urban and rural…

  13. Measurement of positive and negative Goos--Hänchen effects for metallic gratings near Wood anomalies.

    PubMed

    Bonnet, C; Chauvat, D; Emile, O; Bretenaker, F; Le Floch, A; Dutriaux, L

    2001-05-15

    Large Goos-Hänchen effects are isolated for reflection on a metallic grating. These shifts occur in the vicinity of Wood anomalies. Depending on the nature of the anomaly, these displacements are found to be either positive or, contrary to the usual GH effect, clearly negative. Those shifts, associated with forward and backward leaky surface waves, are as large as plus or minus tens of wavelengths for a classic metallic grating.

  14. Oral Squamomelanocytic Tumour in a Dog: a Unique Biphasic Cancer.

    PubMed

    Muscatello, L V; Avallone, G; Benazzi, C; Sarli, G; Porcellato, I; Brachelente, C; Brunetti, B

    2016-01-01

    In human medicine, squamomelanocytic tumour is a malignant cutaneous neoplasm composed of closely intermingled neoplastic squamous cells and melanocytes. A multinodular gingival tumour in a 16-year-old, mixed breed neutered female dog was examined microscopically. Two populations of neoplastic cells, melanocytic and squamous epithelial cells were intermingled. The melanocytic cells were melan-A positive and cytokeratin AE1-AE3 negative and the squamous component was cytokeratin AE1-AE3 positive and melan-A negative. Bovine papillomavirus was not identified by immunohistochemistry or polymerase chain reaction. A diagnosis of squamomelanocytic tumour was made.

  15. Effects of positive cognitions and resourcefulness on caregiver burden among caregivers of persons with dementia.

    PubMed

    Bekhet, Abir K

    2013-08-01

    Currently, 5.4 million persons in the USA are diagnosed with dementia, and this number is projected to rise to 7.7 million by the year 2030. Family caregivers provide up to 80% of the care needed by persons with dementia and published work suggests that caring for persons with dementia can be very costly to caregivers' health. This study examined the mediating and the moderating effects of positive cognitions on the relationship between caregiver burden and resourcefulness in 80 caregivers of persons with dementia. A descriptive, correlational, and cross-sectional design was used in this study. The researcher contacted the administrators at the Alzheimer's Association early stage programs in Southeastern Wisconsin and questionnaires were distributed to interested caregivers. Positive cognitions explained 31% of the variance in resourcefulness (F (1, 78) = 35.46, P < 0.001) and as positive cognitions increased, caregivers' resourcefulness increased. Positive cognitions were found to be a mediator as evidenced by a substantial drop in the beta weight of caregiver burden from B = -0.28 to B = -0.11 when positive cognitions were entered into the equation. Interventions to strengthen positive thinking among caregivers of persons with dementia are needed to help caregivers overcome their burden.

  16. Effect of elastic stockings and ankle positions on the blood velocity in the common femoral vein

    PubMed Central

    Toya, Kaori; Takahashi, Tetsuya; Fujimoto, Yuta; Nishimoto, Teppei; Takasoh, Tomomi; Sasano, Ken; Kusaka, Satomi

    2016-01-01

    [Purpose] The aim of this study was to identify how to effectively use elastic stockings. [Subjects and Methods] Ten young healthy men participated in this study. Time-averaged maximum flow velocity in the common femoral vein was measured for 20 seconds using a pulse Doppler method with a diagnostic ultrasound system under six conditions (three different positions and with and without stockings). Changes of blood flow velocity were compared. [Results] Elastic stockings did not affect the blood flow velocity in the common femoral vein. For both the with stockings condition and without stockings condition, the time-averaged maximum flow velocity in the head-up position was significantly lower than that in the supine and leg-up positions. Time-averaged maximum flow velocity showed no significant difference between the supine position and leg-up position. [Conclusion] Elastic stockings did not affect the blood flow velocity in the common femoral vein, but ankle positions did affect it. Further studies of patients with venous insufficiency are needed. PMID:27799704

  17. Effect of egg weight and position relative to incubator fan on broiler hatchability and chick quality.

    PubMed

    Elibol, O; Brake, J

    2008-09-01

    Two experiments, which included 3 incubators, were carried out to investigate the effects of egg weight and position relative to incubator (setter) fan on embryonic mortality, second quality chicks, and fertile hatchability of broiler eggs. Three egg weight groups termed small (approximately 62.4 g), average (approximately 65.4 g), and large (approximately 68.9 g) were set in either the incubator trolley most distant from the fan (FAR) or in the incubator trolley nearest the fan (NEAR) as would be the case during single-stage operation in this type of incubator. Fertile hatchability decreased in the large egg weight group due to increased percentage late embryonic mortality in experiment 1, and both percentage early and late embryonic mortality in experiment 2. Percentage late embryonic mortality and second quality chicks increased and percentage fertile hatchability decreased for eggs in the FAR position in experiment 1 only. A significant interaction of incubator position x egg weight group for late embryonic mortality, second quality chicks, and fertile hatchability was found in experiment 1, but only late embryonic mortality was so affected in experiment 2. Experiment 2 was conducted so that eggshell temperatures could be measured. Large eggs in the FAR position at transfer time (E 18) exhibited significantly higher eggshell temperatures than did the other groups probably because air velocity or air distribution was modified in the FAR position of the incubator and large eggs were most negatively influenced in the trolley in this position.

  18. Effects of tongue position and lung volume on voluntary maximal tongue protrusion force in humans.

    PubMed

    Saboisky, Julian P; Luu, Billy L; Butler, Jane E; Gandevia, Simon C

    2015-01-15

    Maximal voluntary protrusion force of the human tongue has not been examined in positions beyond the incisors or at different lung volumes. Tongue force was recorded with the tongue tip at eight positions relative to the incisors (12 and 4mm protrusion, neutral and 4, 12, 16, 24 and 32mm retraction) at functional residual capacity (FRC), total lung capacity (TLC) and residual volume (RV) in 15 healthy subjects. Maximal force occurred between 12mm and 32mm retraction (median 16mm). Maximum force at FRC was reproducible at the optimal tongue position across sessions (P=0.68). Across all positions at FRC the average force was highest at 24mm retraction (28.3±5.3N, mean±95% CI) and lowest at 12mm protrusion (49.1±4.6% maximum; P<0.05). Across all tongue positions, maximal force was on average 9.3% lower at FRC than TLC and RV (range: 4.5-12.7% maximum, P<0.05). Retracted positions produce higher-force protrusions with a small effect of lung volume.

  19. Effect of elastic stockings and ankle positions on the blood velocity in the common femoral vein.

    PubMed

    Toya, Kaori; Takahashi, Tetsuya; Fujimoto, Yuta; Nishimoto, Teppei; Takasoh, Tomomi; Sasano, Ken; Kusaka, Satomi

    2016-09-01

    [Purpose] The aim of this study was to identify how to effectively use elastic stockings. [Subjects and Methods] Ten young healthy men participated in this study. Time-averaged maximum flow velocity in the common femoral vein was measured for 20 seconds using a pulse Doppler method with a diagnostic ultrasound system under six conditions (three different positions and with and without stockings). Changes of blood flow velocity were compared. [Results] Elastic stockings did not affect the blood flow velocity in the common femoral vein. For both the with stockings condition and without stockings condition, the time-averaged maximum flow velocity in the head-up position was significantly lower than that in the supine and leg-up positions. Time-averaged maximum flow velocity showed no significant difference between the supine position and leg-up position. [Conclusion] Elastic stockings did not affect the blood flow velocity in the common femoral vein, but ankle positions did affect it. Further studies of patients with venous insufficiency are needed.

  20. The effect of textile-based inductive coil sensor positions for heart rate monitoring.

    PubMed

    Koo, Hye Ran; Lee, Young-Jae; Gi, Sunok; Khang, Seonah; Lee, Joo Hyeon; Lee, Jae-Ho; Lim, Min-Gyu; Park, Hee-Jung; Lee, Jeong-Whan

    2014-02-01

    In the research related to heart rate measurement, few studies have been done using magnetic-induced conductivity sensing methods to measure the heart rate. The aim of this study was to analyze the effect of the position of a textile-based inductive coil sensor on the measurement of the heart rate. In order to assess the capability of the textile-based inductive coil sensor and the repeatability of measured cardiac muscle contractions, we proposed a new quality index based on the morphology of measured signals using a textile-based inductive coil sensor. We initially explored eight potential positions of the inductive sensor in a pilot experiment, followed by three sensor positions in the main experiment. A simultaneously measured electrocardiography (ECG) signal (Lead II) which was used as a reference signal for a comparison of the R-peak location with signals obtained from selected positions of the textile-based inductive coil sensor. The result of the main experiment indicated that the total quality index obtained from the sensor position 'P3', which was located 3 cm away from the left side from the center front line on the chest circumference line, was the highest (QI value = 1.30) among the three positions across all the subjects. This finding led us to conclude that (1) the position of the textile-based inductive coil sensor significantly affected the quality of the measurement results, and that (2) P3 would be the most appropriate position for the textile-based inductive coil sensor for heart rate measurements based on the magnetic-induced conductivity sensing principle.

  1. Effects of positive emotion, extraversion, and dopamine on cognitive stability-flexibility and frontal EEG asymmetry.

    PubMed

    Wacker, Jan

    2017-03-17

    The influence of positive emotions on the balance between cognitive stability and flexibility has been suggested to (a) differ among various positive emotional/motivational states (e.g., of varying approach motivation intensity), and (b) be mediated by brain dopamine (DA). Frontal EEG alpha asymmetry (ASY) is considered an indicator of approach motivational states and may be modulated by DA. The personality trait of extraversion is strongly linked to positive emotions and is now thought to reflect DA-based individual differences in incentive/approach motivation. The present study independently manipulated positive emotion (high approach wanting-expectancy [WE] vs. low approach warmth-liking [WL]) and dopamine (placebo vs. DA D2 blocker sulpiride) to examine their effects on both cognitive stability-flexibility and emotion-related ASY changes. The results showed numerically lower stability-flexibility in WE versus WL under placebo and a complete reversal of this effect under the D2 blocker, no differentiation between WE and WL groups in terms of emotion-related ASY change, but an association between self-reported WE and WL and ASY changes toward left and right frontal cortical activity, respectively. Finally, extraversion was positively associated with both stability-flexibility and ASY changes toward left frontal cortical activity under placebo, and these associations were completely reversed under the D2 blocker. The results (a) support a dopaminergic basis for frontal EEG asymmetry, extraversion, and the modulating effect of positive emotions on stability-flexibility, and (b) extend previous reports of cognitive differences between introverts and extraverts.

  2. Under pressure: the effects of stress on positive and negative relationship behaviors.

    PubMed

    Lewandowski, Gary W; Mattingly, Brent A; Pedreiro, Annabelle

    2014-01-01

    This study investigates the effects of acute stress on positive and negative relationship behaviors, specifically assurances and attention to alternatives. A sample of 129 college students were randomly assigned to either a high or low stress condition, then were led to believe they had the opportunity to interact with attractive potential relationship partners and list compliments about their current partner. Results indicated that those in the high stress condition gave their partner fewer assurances and paid more attention to alternatives. These results suggest that when individuals experience acute stress, they may engage in fewer positive relationship behaviors and more behaviors that are potentially harmful to their relationship.

  3. Assessing the effects of positive feedback and reinforcement in the introduction phase of an ergonomic intervention.

    PubMed

    Brandenburg, David L; Mirka, Gary A

    2005-01-01

    Resistance to change is common in ergonomic interventions, often resulting in negative consequences when the intervention's effectiveness is studied. A lab-based study assessed the effects of positive reinforcement during the intervention process. On Day 1 all participants performed a simple screw-driving task that placed stress on the cervicobrachial region through static loading. On Day 2 a control group received basic information about ergonomics and then performed the task using an ergonomic intervention that has been shown to reduce loading on these muscle groups. The experimental group received the same basic information but also received positive reinforcement while performing the task with the ergonomic intervention. Subjective task assessment surveys and body-part discomfort surveys were administered, and these, along with speed of performance, were assessed in both groups. The results showed a significantly (p < .05) more positive subjective impression of the intervention for the feedback group than for the control group (29%-57% improvement) with no real changes in either the performance or discomfort levels. Applications of this research include improving workers' acceptance of ergonomic interventions in industrial and other settings. The reinforcement technique evaluated in this paper has yielded consistently positive effects in our ongoing ergonomic intervention research.

  4. Monte Carlo simulation of neutron noise effects on beam position determination at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Awwal, Abdul A. S.; Leach, Richard R.; Datte, Philip; Manuel, Anastacia

    2013-09-01

    Images obtained through charged coupled device (CCD) cameras in the National Ignition Facility (NIF) are crucial to precise alignment of the 192 laser beams to the NIF target-chamber center (TCC). Cameras in and around the target chamber are increasingly exposed to the effects of neutron radiation as the laser power is increased for high energy fusion experiments. NIF was carefully designed to operate under these conditions. The present work examines the degradation of the measured TCC camera position accuracy resulting from the effects of neutron radiation on the sensor and verifies operation within design specifications. Both synthetic and real beam images are used for measuring position degradation. Monte Carlo simulations based on camera performance models are used to create images with added neutron noise. These models predict neutron induced camera noise based on exposure estimates of the cumulative single-shot fluence in the NIF environment. The neutron induced noise images are used to measure beam positions on a target calculated from the alignment images with the added noise. The effects of this noise are also determined using noise artifacts from real camera images viewing TCC to estimate beam position uncertainty.

  5. Reciprocal Effects of Positive Future Expectations, Threats to Safety, and Risk Behavior Across Adolescence.

    PubMed

    Prince, Dana M; Epstein, Marina; Nurius, Paula S; Gorman-Smith, Deborah; Henry, David B

    2016-09-12

    We examined the reciprocal relationships among positive future expectations, expected threats to future safety, depression, and individual substance use and delinquency using 4 waves of data (N = 248-338) from African American and Latino adolescent male participants in the Chicago Youth Development Study. Individual positive future expectations and expected threats to safety were assessed at each wave and modeled as latent constructs. Individual substance use and delinquency were assessed at each wave and represented as ordinal variables ranging from low to high. Categorical autoregressive cross-lagged structural models were used to examine the hypothesized reciprocal relationships between both aspects of future expectations construct and risk behavior across adolescence. Analyses show that future expectations has important effects on youth substance use and involvement in delinquency, both of which in turn decrease positive expectations and increase expectation of threats to future safety across adolescence. Similarly, low positive expectations for the future continued to predict increased substance use and involvement in delinquency. The expected threats to safety construct was significantly correlated with delinquency within time. These effects are observed across adolescence after controlling for youth depression and race. Findings support the reciprocal effects hypothesis of a negative reinforcing cycle in the relationships between future expectations and both substance use and involvement in delinquent behavior across adolescence. The enduring nature of these relationships underscores the importance of future expectation as a potential change mechanism for intervention and prevention efforts to promote healthy development; vulnerable racial and ethnic minority male adolescents may especially benefit from such intervention.

  6. [Effects of land use type and slope position on soil physical properties in loess tableland area].

    PubMed

    Li, Zhi; Liu, Wen-Zhao; Wang, Qiu-Xian

    2008-06-01

    Soil samples under different land use types and at different slope positions in the Wangdonggou watershed of loess tableland area were collected to determine their particle composition, bulk density (pb), and saturated hydraulic conductivity (Ks), and the effects of land use type and slope position on the soil physical properties were studied in virtue of the variation coefficient and non-parameter tests. The results showed that the physical properties of soil varied in horizontal direction and vertical profile, however at the same slope position or under the same land use type, the pb and particle composition were similar. In horizontal direction, Ks varied strongly, slit content and pb varied weakly, and clay and sand contents varied medially. In vertical profile, soil particles had a continuous distribution, but pb and Ks varied greatly in 0-25 cm layer. With the slope degree descended, soil contained more clay and had a higher pb, and Ks increased. At upper and middle slopes, soil physical properties were similar, and thus, could be merged into one in related researches. There was a significant difference in soil physical properties between grassland and other land use types, which was mainly due to the effects of slope position, but the soil physical properties in farmland and orchard were similar, indicating the important effects of human activities.

  7. Analysis of the galactosyltransferase reaction by positional isotope exchange and secondary deuterium isotope effects

    SciTech Connect

    Kim, S.C.; Singh, A.N.; Raushel, F.M.

    1988-11-15

    The mechanism of the galactosyltransferase-catalyzed reaction was probed using positional isotope exchange, alpha-secondary deuterium isotope effects, and inhibition studies with potential transition state analogs. Incubation of (beta-18O2, alpha beta-18O)UDP-galactose and alpha-lactalbumin with galactosyltransferase from bovine milk did not result in any positional isotope exchange. The addition of 4-deoxy-4-fluoroglucose as a dead-end inhibitor did not induce any detectable positional isotope exchange. alpha-Secondary deuterium isotope effects of 1.21 +/- 0.04 on Vmax and 1.05 +/- 0.04 on Vmax/KM were observed for (1-2H)-UDP-galactose. D-Glucono-1,5-lactone, D-galactono-1,4-lactone, D-galactono-1,5-lactone, nojirimycin, and deoxynojirimycin, did not inhibit the galactosyl transfer reaction at concentrations less than 1.0 mM. The magnitude of the secondary deuterium isotope effect supports a mechanism in which the anomeric carbon of the galactosyl moiety has substantial sp2 character in the transition state. Therefore, the cleavage of the bond between the galactose and UDP moieties in the transition state has proceeded to a much greater extent than the formation of the bond between the galactose and the incoming glucose. The lack of a positional isotope exchange reaction indicates that the beta-phosphoryl group of the UDP is not free to rotate in the absence of an acceptor substrate.

  8. Research on effects of baffle position in an integrating sphere on the luminous flux measurement

    NASA Astrophysics Data System (ADS)

    Lin, Fangsheng; Li, Tiecheng; Yin, Dejin; Lai, Lei; Xia, Ming

    2016-09-01

    In the field of optical metrology, luminous flux is an important index to characterize the quality of electric light source. Currently, the majority of luminous flux measurement is based on the integrating sphere method, so measurement accuracy of integrating sphere is the key factor. There are plenty of factors affecting the measurement accuracy, such as coating, power and the position of light source. However, the baffle which is a key part of integrating sphere has important effects on the measurement results. The paper analyzes in detail the principle of an ideal integrating sphere. We use moving rail to change the relative position of baffle and light source inside the sphere. By experiments, measured luminous flux values at different distances between the light source and baffle are obtained, which we used to take analysis of the effects of different baffle position on the measurement. By theoretical calculation, computer simulation and experiment, we obtain the optimum position of baffle for luminous flux measurements. Based on the whole luminous flux measurement error analysis, we develop the methods and apparatus to improve the luminous flux measurement accuracy and reliability. It makes our unifying and transferring work of the luminous flux more accurate in East China and provides effective protection for our traceability system.

  9. Of mice and mallards: Positive indirect effects of coexisting prey on waterfowl nest success

    USGS Publications Warehouse

    Ackerman, Joshua T.

    2002-01-01

    Coexisting prey species interact indirectly via their shared predators when one prey type influences predation rates of the second prey type. In a temperate system where the predominant shared predator is a generalist, I studied the indirect effects of rodent populations on waterfowl nest success, both within the nesting season among sites and among years. Among six to ten upland fields (14 to 27 ha), mallard (Anas platyrhynchos) nest success was positively correlated with rodent abundance in all three years of the study. After removing year effects, mallard nest success remained positively correlated with the relative abundance of rodents. Of the rodent species present, California voles (Microtus californicus) were the most important coexisting prey type influencing nest success. Among years, mallard nest success was positively correlated with vole abundance; the asymptotic relationship suggests a threshold response to vole abundance, beyond which predators become satiated and additional voles do little to affect nest success. I tested and rejected three alternative explanations for the observed positive correlation between mallard nest success and rodent abundance that do not involve an indirect effect of coexisting prey populations. The influences of dense nesting cover, nesting density, and predator activity did not explain the observed patterns of nest success. These results suggest that rodent populations buffer predation on waterfowl nests, both within and among years, via the behavioral responses of shared predators to coexisting prey.

  10. Distracted by pleasure: Effects of positive versus negative valence on emotional capture under load.

    PubMed

    Gupta, Rashmi; Hur, Young-Jin; Lavie, Nilli

    2016-04-01

    We report 3 experiments examining the effects of positive versus negative valence and perceptual load in determining attention capture by irrelevant emotional distractors. Participants performed a letter search task searching for 1 of 2 target letters (X or N) in conditions of either low perceptual load (circular nontarget letters) or high perceptual load (angular nontarget letters that are similar to the target letters). On 25% of the trials an irrelevant emotional distractor was presented at the display center and participants were instructed to ignore it. The distractor stimulus was either positive or negative and was selected from 3 different classes: IAPS pictures of erotica or mutilated bodies (Experiment 1), happy or angry faces (Experiment 2), and faces associated with gain or loss in a prior value-learning phase involving a betting game (Experiment 3). The results showed a consistent pattern of interaction of load and valence across the 3 experiments. Irrelevant emotional distractors produced interference effects on search reaction time (RT) in conditions of low load, with no difference between negative and positive valence. High perceptual load, however, consistently reduced interference from the negative-valence distractors, but had no effect on the positive-valence distractors. As these results were consistently found across 3 different categories of emotional distractors, they suggest the general conclusion that attentional capture by irrelevant emotional distractors depends on both their valence and the level of perceptual load in the task and highlight the special status of distractors associated with pleasure.

  11. The acute effects of nicotine on positive and negative affect in adolescent smokers.

    PubMed

    Kassel, Jon D; Evatt, Daniel P; Greenstein, Justin E; Wardle, Margaret C; Yates, Marisa C; Veilleux, Jennifer C

    2007-08-01

    Although adolescent cigarette smoking remains a critical public health concern, little is known about the reinforcing mechanisms governing smoking in this vulnerable population. To assess predictions derived from both positive and negative reinforcement models of drug use, the authors measured the acute effects of nicotine, as administered via tobacco cigarettes, on both positive and negative affect in a group of 15- to 18-year-old smokers. A matched group of nonsmokers served as a comparison group. Findings revealed that whereas adolescents who smoked a cigarette experienced reductions in both positive and negative affect, the observed reductions in negative affect were moderated by nicotine content of the cigarette (high yield vs. denicotinized), level of nicotine dependence, level of baseline craving, and smoking expectancies pertinent to negative affect regulation. Nonsmokers experienced no change in affect over the 10-min assessment period, and no interaction effects were observed for positive affect. Overall, the findings conform to a negative reinforcement model of nicotine effects and strongly suggest that, even among young light smokers, nicotine dependence and resultant withdrawal symptomatology may serve as motivating factors governing smoking behavior.

  12. Biphasic thermoelectric materials derived from the half-Heusler/full-Heusler system Ti-Ni-Sn

    NASA Astrophysics Data System (ADS)

    Douglas, Jason Everett

    comparative energies of formation. We discuss the effects of thermal treatment on the microstructure of biphasic materials comprising hH and fH phases, as well as on their associated thermal transport properties. The fH phase is observed to be semi-coherent with the hH majority phase. Microstructural analysis, both in 2-D and 3-D, shows that the fH solidifies first and the hH then nucleates on these fH dendrites as the melt becomes depleted of Ni. The various heat treatments generated microstructures containing second phase precipitates ranging from 10 nm to a few micrometers, reducing the connectivity of the percolated network observed previously. The materials were characterized with regard to morphology, size, shape and orientation relationship of the fH precipitates with the hH matrix. The precipitate size and morphology are very sensitive to Ni concentration in fH/hH phase. The thermal conductivity is found to drop by 50% as the precipitate size increases; however, this enhancement was not retained after high temperature exposure. In addition to the microstructural implications of TiNi 1+xSn alloying, the (crystal) structural implications of excess Ni in the TiNiSn hH compound were investigated next through a combination of synchrotron x-ray and neutron scattering studies, in conjunction with first principles density functional theory calculations on supercells. Despite the phase diagram suggesting that TiNiSn is a line compound with no solid solution, for small x in TiNi 1+xSn there is indeed an appearance--from careful analysis of the scattering--of some solubility, with the excess Ni occupying the interstitial tetrahedral site in the hH structure. The analysis performed here would point to the excess Ni not being statistically distributed, but rather occurring as coherent nanoclusters. First principles calculations of energetics, carried out using supercells, support a scenario of Ni interstitials clustering, rather than a statistical distribution. Finally, we also

  13. The Positive Effects of Trait Emotional Intelligence during a Performance Review Discussion – A Psychophysiological Study

    PubMed Central

    Salminen, Mikko; Ravaja, Niklas

    2017-01-01

    Performance review discussions of real manager–subordinate pairs were examined in two studies to investigate the effects of trait emotional intelligence (EI) on dyad member’s felt and expressed emotions. Altogether there were 84 managers and 122 subordinates in two studies using 360 measured and self-reported trait EI. Facial electromyography, and frontal electroencephalography (EEG) asymmetry were collected continuously. Manager’s high trait EI was related to increased positive valence emotional facial expressions in the dyad during the discussions. The managers also had more EEG frontal asymmetry indicating approach motivation, than the subordinates. In addition, actor and partner effects and actor × partner interactions, and interactions between the role and actor or partner effect of trait EI were observed. Both actor and partner trait EI were related to more positive self-reported emotional valence. The results imply that trait EI has a role in organizational social interaction.

  14. BodiMojo: effective Internet-based promotion of positive body image in adolescent girls.

    PubMed

    Franko, Debra L; Cousineau, Tara M; Rodgers, Rachel F; Roehrig, James P

    2013-09-01

    This study tested the efficacy of an Internet-based health promotion program, BodiMojo, designed to promote positive body image in adolescents. Participants were 178 students (mean age 15.2 years, 67.6% ethnic minority) in three public high schools. Intervention groups used BodiMojo for four weekly health class periods, while controls participated in their usual health curriculum. Body image measures were given at baseline, post-intervention, and 3 months. Girls reported decreased body dissatisfaction (p<.05), decreased physical appearance comparison (p<.05), and increased appearance satisfaction (p<.05), relative to controls. Effects were not maintained at 3-month follow-up. No significant differences were found between the intervention and control groups with boys. Moderation analyses suggested positive effects for diverse adolescents as well as those who were overweight or indicated baseline high body dissatisfaction. BodiMojo appears to be modestly effective in decreasing body image concerns among adolescent girls in the short term.

  15. Effect of Radio Frequency Interference (RFI) on the Precision of GPS Relative Positioning

    NASA Astrophysics Data System (ADS)

    Idris, A. N.; Sathyamoorthy, D.; Suldi, A. M.; Hamid, J. R. A.

    2014-02-01

    The successful of GPS observations are dependent on several factors between satellite vehicles and GPS receivers, where low GPS power levels have led to the threat of radio frequency interference (RFI) on the GPS signals. This study was conducted to evaluate the effect of RFI on the precision of positions of single and dual frequency receivers through relative positioning technique by taking into consideration the radius of GPS receiver from interference source, length of baseline and response of rejection. Several tests were conducted in real environment by simulating the interference signal towards GPS receivers in the nominated GPS L1 and L2 bands. Calculations were made to indentify the distance and interference signal power between interference source and GPS receiver in order to investigate the level of effect. To be able to study this effect on the precision of GPS positions, the 3D residual positions and geometric dilution of precision (GDOP) have been used. The findings of this study have demonstrated that a sufficient time for the GPS receiver to respond in particular interference signal power level and the radius from the interference source were made as compared to previous work. It was also indicated that the residual positions and GDOPs were affected proportionally when nearly to interference source but not similar for both days due to GPS coverage and other probable errors. Therefore, a good investigation on RFI towards GPS signals should be conducted in secured environment which can control the various GPS error parameters in order to obtain a reliable result on this effect.

  16. Does being attractive always help? Positive and negative effects of attractiveness on social decision making.

    PubMed

    Agthe, Maria; Spörrle, Matthias; Maner, Jon K

    2011-08-01

    Previous studies of organizational decision making demonstrate an abundance of positive biases directed toward highly attractive individuals. The current research, in contrast, suggests that when the person being evaluated is of the same sex as the evaluator, attractiveness hurts, rather than helps. Three experiments assessing evaluations of potential job candidates (Studies 1 and 3) and university applicants (Study 2) demonstrated positive biases toward highly attractive other-sex targets but negative biases toward highly attractive same-sex targets. This pattern was mediated by variability in participants' desire to interact with versus avoid the target individual (Studies 1 and 2) and was moderated by participants' level of self-esteem (Study 3); the derogation of attractive same-sex targets was not observed among people with high self-esteem. Findings demonstrate an important exception to the positive effects of attractiveness in organizational settings and suggest that negative responses to attractive same-sex targets stem from perceptions of self-threat.

  17. Effect of structural composition and position of occlusion on the legibility of occluded Chinese characters.

    PubMed

    Tsao, Yung-Chin; Liao, Ching-Chih

    2015-04-01

    The study examined the effect of structural composition, position of occlusion, and education background on response time and accuracy rate of adult participants in recognition of occluded Chinese characters used in graphic design. Based on 18 Chinese characters selected from the top 4,000 most commonly used characters, a recognition experiment was conducted. Results indicated that, for the characters with two different composition structures, the right position was the best position of occlusion because the recognition of the radical or feature of a character would be least affected, leading to a shorter response time and more accurate reading comprehension. Educational background did not have a significant influence on response time and recognition accuracy.

  18. Effects of different sitting positions on skin temperature of the lower extremity.

    PubMed

    Namkoong, Seung; Shim, JeMyung; Kim, SungJoong; Shim, JungMyo

    2015-08-01

    [Purpose] The purpose of this study was to identify the effect of different sitting positions on the skin temperature of the lower extremity. [Subjects] The subjects of this study were 23 healthy university students (8 males, 15 females). [Methods] Normal sitting (NS), upper leg cross (ULC) and ankle on knee (AOK) positions were conducted to measure the changes in skin temperature using digital infrared thermographic imaging (DITI). [Results] ULC upper ankle, NS upper shin, ULC upper shin and NS lower shin showed significant declines in temperature with time. [Conclusion] These finding suggest that the ULC and NS sitting positions cause decline of blood flow volume to the lower extremity resulting in decrease of temperature of the lower extremity. Especially, sitting with the legs crossed interferes with the circulation of blood flowing volume much more than just sitting in a chair.

  19. Effect of Knee Position on Quadriceps Muscle Force Steadiness and Activation Strategies

    PubMed Central

    Krishnan, Chandramouli; Allen, Eric J.; Williams, Glenn N.

    2010-01-01

    Introduction This study investigated the effect of knee position on quadriceps force steadiness and activation strategies. Methods Quadriceps force steadiness was evaluated in twenty-two volunteers at two knee positions by testing their ability to regulate submaximal force. Muscle activation strategies were studied in both time and frequency domains using surface electromyography. Results Quadriceps force fluctuations and the associated agonist and antagonist activity were significantly higher at 90° than at 30° of flexion (P < 0.05). The quadriceps median frequency recorded at 30° was significantly higher than at 90° of flexion (P < 0.05). Regression analyses revealed that force steadiness was related to quadriceps activation and median frequency (P < 0.001), but not to hamstring coactivation (P > 0.05). Discussion The results indicate that knee position significantly affects quadriceps force steadiness and activation strategies. This finding may have important implications for designing a force control testing protocol and interpreting test results. PMID:21404288

  20. Short Alleles, Bigger Smiles? The Effect of 5-HTTLPR on Positive Emotional Expressions

    PubMed Central

    Haase, Claudia M.; Beermann, Ursula; Saslow, Laura R.; Shiota, Michelle N.; Saturn, Sarina R.; Lwi, Sandy J.; Casey, James J.; Nguyen, Nguyen K.; Whalen, Patrick K.; Keltner, Dacher J.; Levenson, Robert W.

    2015-01-01

    The present research examined the effect of the 5-HTTLPR polymorphism in the serotonin transporter gene on objectively coded positive emotional expressions (i.e., laughing and smiling behavior objectively coded using the Facial Action Coding System). Three studies with independent samples of participants were conducted. Study 1 examined young adults watching still cartoons. Study 2 examined young, middle-aged, and older adults watching a thematically ambiguous yet subtly amusing film clip. Study 3 examined middle-aged and older spouses discussing an area of marital conflict (which typically produces both positive and negative emotion). Aggregating data across studies, results showed that the short allele of 5-HTTLPR predicted heightened positive emotional expressions. Results remained stable when controlling for age, gender, ethnicity, and depressive symptoms. These findings are consistent with the notion that the short allele of 5-HTTLPR functions as an emotion amplifier, which may confer heightened susceptibility to environmental conditions. PMID:26029940

  1. Stress processes in HIV-positive African American mothers: moderating effects of drug abuse history.

    PubMed

    Burns, Myron J; Feaster, Daniel J; Mitrani, Victoria B; Ow, Christina; Szapocznik, José

    2008-01-01

    This study examined the mechanism by which stressors, dissatisfaction with family, perceived control, social support, and coping were related to psychological distress in a sample of HIV-positive African American mothers. Additional analyses explored whether women who had a history of a drug abuse or dependence diagnosis differed either on levels of the study variables or the model pathways. The results indicated that HIV-positive African American mothers who had higher levels of stressors perceived their stressors as a whole to be less controllable. Coping resources, available social support and perceived control, were positively associated with active coping and negatively associated with psychological distress. Avoidant coping was the most important predictor of psychological distress. Furthermore, the effect of avoidant coping on psychological distress was stronger for mothers with a history of drug diagnosis. The implications of these findings for targeting interventions are discussed.

  2. Effect of Orthographic Processes on Letter Identity and Letter-Position Encoding in Dyslexic Children

    PubMed Central

    Reilhac, Caroline; Jucla, Mélanie; Iannuzzi, Stéphanie; Valdois, Sylviane; Démonet, Jean-François

    2012-01-01

    The ability to identify letters and encode their position is a crucial step of the word recognition process. However and despite their word identification problem, the ability of dyslexic children to encode letter identity and letter-position within strings was not systematically investigated. This study aimed at filling this gap and further explored how letter identity and letter-position encoding is modulated by letter context in developmental dyslexia. For this purpose, a letter-string comparison task was administered to French dyslexic children and two chronological age (CA) and reading age (RA)-matched control groups. Children had to judge whether two successively and briefly presented four-letter strings were identical or different. Letter-position and letter identity were manipulated through the transposition (e.g., RTGM vs. RMGT) or substitution of two letters (e.g., TSHF vs. TGHD). Non-words, pseudo-words, and words were used as stimuli to investigate sub-lexical and lexical effects on letter encoding. Dyslexic children showed both substitution and transposition detection problems relative to CA-controls. A substitution advantage over transpositions was only found for words in dyslexic children whereas it extended to pseudo-words in RA-controls and to all type of items in CA-controls. Letters were better identified in the dyslexic group when belonging to orthographically familiar strings. Letter-position encoding was very impaired in dyslexic children who did not show any word context effect in contrast to CA-controls. Overall, the current findings point to a strong letter identity and letter-position encoding disorder in developmental dyslexia. PMID:22661961

  3. Bolus-dependent dosimetric effect of positioning errors for tangential scalp radiotherapy with helical tomotherapy.

    PubMed

    Lobb, Eric

    2014-01-01

    The dosimetric effect of errors in patient position is studied on-phantom as a function of simulated bolus thickness to assess the need for bolus utilization in scalp radiotherapy with tomotherapy. A treatment plan is generated on a cylindrical phantom, mimicking a radiotherapy technique for the scalp utilizing primarily tangential beamlets. A planning target volume with embedded scalplike clinical target volumes (CTVs) is planned to a uniform dose of 200cGy. Translational errors in phantom position are introduced in 1-mm increments and dose is recomputed from the original sinogram. For each error the maximum dose, minimum dose, clinical target dose homogeneity index (HI), and dose-volume histogram (DVH) are presented for simulated bolus thicknesses from 0 to 10mm. Baseline HI values for all bolus thicknesses were in the 5.5 to 7.0 range, increasing to a maximum of 18.0 to 30.5 for the largest positioning errors when 0 to 2mm of bolus is used. Utilizing 5mm of bolus resulted in a maximum HI value of 9.5 for the largest positioning errors. Using 0 to 2mm of bolus resulted in minimum and maximum dose values of 85% to 94% and 118% to 125% of the prescription dose, respectively. When using 5mm of bolus these values were 98.5% and 109.5%. DVHs showed minimal changes in CTV dose coverage when using 5mm of bolus, even for the largest positioning errors. CTV dose homogeneity becomes increasingly sensitive to errors in patient position as bolus thickness decreases when treating the scalp with primarily tangential beamlets. Performing a radial expansion of the scalp CTV into 5mm of bolus material minimizes dosimetric sensitivity to errors in patient position as large as 5mm and is therefore recommended.

  4. Bolus-dependent dosimetric effect of positioning errors for tangential scalp radiotherapy with helical tomotherapy

    SciTech Connect

    Lobb, Eric

    2014-04-01

    The dosimetric effect of errors in patient position is studied on-phantom as a function of simulated bolus thickness to assess the need for bolus utilization in scalp radiotherapy with tomotherapy. A treatment plan is generated on a cylindrical phantom, mimicking a radiotherapy technique for the scalp utilizing primarily tangential beamlets. A planning target volume with embedded scalplike clinical target volumes (CTVs) is planned to a uniform dose of 200 cGy. Translational errors in phantom position are introduced in 1-mm increments and dose is recomputed from the original sinogram. For each error the maximum dose, minimum dose, clinical target dose homogeneity index (HI), and dose-volume histogram (DVH) are presented for simulated bolus thicknesses from 0 to 10 mm. Baseline HI values for all bolus thicknesses were in the 5.5 to 7.0 range, increasing to a maximum of 18.0 to 30.5 for the largest positioning errors when 0 to 2 mm of bolus is used. Utilizing 5 mm of bolus resulted in a maximum HI value of 9.5 for the largest positioning errors. Using 0 to 2 mm of bolus resulted in minimum and maximum dose values of 85% to 94% and 118% to 125% of the prescription dose, respectively. When using 5 mm of bolus these values were 98.5% and 109.5%. DVHs showed minimal changes in CTV dose coverage when using 5 mm of bolus, even for the largest positioning errors. CTV dose homogeneity becomes increasingly sensitive to errors in patient position as bolus thickness decreases when treating the scalp with primarily tangential beamlets. Performing a radial expansion of the scalp CTV into 5 mm of bolus material minimizes dosimetric sensitivity to errors in patient position as large as 5 mm and is therefore recommended.

  5. Effect of working position on vertical motion straightness of open hydrostatic guideways in grinding machine

    NASA Astrophysics Data System (ADS)

    Zha, Jun; Wang, Zhiwei; Xue, Fei; Chen, Yaolong

    2017-01-01

    Hydrostatic guideways have various applications in precision machine tools due to their high motion accuracy. The analysis of motion straightness in hydrostatic guideways is generally ignoring the external load on the slider. A variation force also exists, caused by the different working positions, together with the dead load of the slider and that of other auxiliary devices. The effect of working position on vertical motion straightness is investigated based on the equivalent static model, considering the error averaging effort of pressured oil film in open hydrostatic guideways. Open hydrostatic guideways in LGF1000 are analyzed with this approach. The theoretical results show that the slider has maximum vertical motion straightness when the working position is closer the guiderail of Y axis. The vertical motion straightness reaches a minimum value as the working position is located at the center of the two guiderails on the Y axis. The difference between the maximum and minimum vertical motion straightness is 34.7%. The smaller vertical motion straightness is attributed to the smaller spacing of the two pads centers, along the Y direction. The experimental results show that the vertical motion straightness is 4.15 μm/1200 mm, when the working position is located in the middle of the X beam, and 5.08 μm/1200 mm, when the working position is approaching the Y guiderails, denoting an increase of 18.3%. The changing trends of the measured results validate the correctness of the theoretical model. The research work can be used to reveal the variation law of accuracy of the open hydrostatic guideways, under different working positions, to predict the machining precision, and provides the basis for an error compensation strategy for gantry type grinding machines.

  6. Effect of The Swimmer’s Head Position on Passive Drag

    PubMed Central

    Cortesi, Matteo; Gatta, Giorgio

    2015-01-01

    The aim of this study was to investigate the effect of the head position on passive drag with a towing-line experiment in a swimming pool. The tests were performed on ten male swimmers with regional level swimming skills and at least 10 years of competitive swimming experience. They were towed underwater (at a depth of 60 cm) at three speeds (1.5, 1.7 and 1.9 m/s) and in two body positions (arms above the swimmer’s head and arms alongside the body). These two body positions were repeated while the swimmer’s head was positioned in three different ways: head-up, head-middle and head-down in relation to the body’s horizontal alignment. The results showed a reduction of 4–5.2% in the average passive drag at all speeds when the head was down or aligned to the swimmer’s arms alongside the body, in comparison to the head-up position. A major significant decrease of 10.4–10.9% (p < 0.05) was shown when the head was down or aligned at the swimmer’s arms above the swimmer’s head. The passive drag tended to decrease significantly by a mean of 17.6% (p < 0.001) for all speeds examined with the arms alongside the body position rather than with the arms above the head position. The swimmer’s head location may play an important role in reducing hydrodynamic resistance during passive underwater gliding. PMID:26839604

  7. Testing the Effect of Medical Positive Reinforcement Training on Salivary Cortisol Levels in Bonobos and Orangutans

    PubMed Central

    Behringer, Verena; Stevens, Jeroen M. G.; Hohmann, Gottfried; Möstl, Erich; Selzer, Dieter; Deschner, Tobias

    2014-01-01

    The management of captive animals has been improved by the establishment of positive reinforcement training as a tool to facilitate interactions between caretakers and animals. In great apes, positive reinforcement training has also been used to train individuals to participate in simple medical procedures to monitor physical health. One aim of positive reinforcement training is to establish a relaxed atmosphere for situations that, without training, might be very stressful. This is especially true for simple medical procedures that can require animals to engage in behaviours that are unusual or use unfamiliar medical devices that can be upsetting. Therefore, one cannot exclude the possibility that the training itself is a source of stress. In this study, we explored the effects of medical positive reinforcement training on salivary cortisol in two groups of captive ape species, orangutans and bonobos, which were familiar to this procedure. Furthermore, we successfully biologically validated the salivary cortisol assay, which had already been validated for bonobos, for orangutans. For the biological validation, we found that cortisol levels in orangutan saliva collected during baseline conditions were lower than in samples collected during three periods that were potentially stressful for the animals. However, we did not find significant changes in salivary cortisol during medical positive reinforcement training for either bonobos or orangutans. Therefore, for bonobos and orangutans with previous exposure to medical PRT, the procedure is not stressful. Thus, medical PRT provides a helpful tool for the captive management of the two species. PMID:25250566

  8. Effect of the lower boundary position of the Fourier equation on the soil energy balance

    NASA Astrophysics Data System (ADS)

    Shufen, Sun; Xia, Zhang

    2004-12-01

    In this study, the effect of the lower boundary position selection for the Fourier equation on heat transfer and energy balance in soil is evaluated. A detailed numerical study shows that the proper position of the lower boundary is critical when solving the Fourier equation by using zero heat flux as the lower boundary condition. Since the position defines the capacity of soil as a heat sink or source, which absorbs and stores radiation energy from the sky in summer and then releases the energy to the atmosphere in winter, and regulates the deep soil temperature distribution, the depth of the position greatly influences the heat balance within the soil as well as the interaction between the soil and the atmosphere. Based on physical reasoning and the results of numerical simulation, the proper depth of the position should be equal to approximately 3 times of the annual heat wave damping depth. For most soils, the proper lower boundary depth for the Fourier equation should be around 8 m to 15 m, depending on soil texture.

  9. Effect of positively and negatively charged liposomes on skin permeation of drugs.

    PubMed

    Ogiso, T; Yamaguchi, T; Iwaki, M; Tanino, T; Miyake, Y

    2001-01-01

    To clarify the effect of the surface charge of liposomes on percutaneous absorption, the permeation of liposomal drugs through rat skin was investigated in vitro and in vivo. Liposomes were prepared using egg yolk lecithin (EPC, phase transition temperature, -15 to -17 degrees C), cholesterol and dicetylphosphate (DP) or stearylamine (SA) (10:1:1, mol/mol). Also examined was the penetration behavior of positively and negatively charged liposomes, using a fluorescent probe (Nile Red). The in vitro penetration rate of melatonin (MT) entrapped in negatively charged liposomes was higher than that of positively charged ones (p<0.05). When the percutaneous absorption of ethosuximide (ES) encapsulated was estimated in vivo, the absorption of ES from negatively charged liposomes was slightly higher than that from positively charged liposomes. Additionally, the absorption of ES from both types of liposomes was superior to that from the lipid mixtures consisting of the same composition as the vesicles. The percutaneous absorption of betahistine (BH) from a gel formulation containing negatively charged liposomes of BH was much more than that from the formulation with positively charged ones, with 2-fold higher AUC (p<0.05). Histological studies revealed that the negatively charged liposomes diffused to the dermis and the lower portion of hair follicles through the stratum corneum and the follicles much faster than the positive vesicles at the initial time stage after application. Thus, the rapid penetration of negatively charged liposomes would contribute to the increased permeation of drugs through the skin.

  10. An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation

    PubMed Central

    Islam, Md. Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4–10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  11. Effects of anatomical position on esophageal transit time: A biomagnetic diagnostic technique

    PubMed Central

    Cordova-Fraga, Teodoro; Sosa, Modesto; Wiechers, Carlos; la Roca-Chiapas, Jose Maria De; Moreles, Alejandro Maldonado; Bernal-Alvarado, Jesus; Huerta-Franco, Raquel

    2008-01-01

    AIM: To study the esophageal transit time (ETT) and compare its mean value among three anatomical inclinations of the body; and to analyze the correlation of ETT to body mass index (BMI). METHODS: A biomagnetic technique was implemented to perform this study: (1) The transit time of a magnetic marker (MM) through the esophagus was measured using two fluxgate sensors placed over the chest of 14 healthy subjects; (2) the ETT was assessed in three anatomical positions (at upright, fowler, and supine positions; 90º, 45º and 0º, respectively). RESULTS: ANOVA and Tuckey post-hoc tests demonstrated significant differences between ETT mean of the different positions. The ETT means were 5.2 ± 1.1 s, 6.1 ± 1.5 s, and 23.6 ± 9.2 s for 90º, 45º and 0º, respectively. Pearson correlation results were r = -0.716 and P < 0.001 by subjects’ anatomical position, and r = -0.024 and P > 0.05 according the subject’s BMI. CONCLUSION: We demonstrated that using this biomagnetic technique, it is possible to measure the ETT and the effects of the anatomical position on the ETT. PMID:18837088

  12. Testing the effect of medical positive reinforcement training on salivary cortisol levels in bonobos and orangutans.

    PubMed

    Behringer, Verena; Stevens, Jeroen M G; Hohmann, Gottfried; Möstl, Erich; Selzer, Dieter; Deschner, Tobias

    2014-01-01

    The management of captive animals has been improved by the establishment of positive reinforcement training as a tool to facilitate interactions between caretakers and animals. In great apes, positive reinforcement training has also been used to train individuals to participate in simple medical procedures to monitor physical health. One aim of positive reinforcement training is to establish a relaxed atmosphere for situations that, without training, might be very stressful. This is especially true for simple medical procedures that can require animals to engage in behaviours that are unusual or use unfamiliar medical devices that can be upsetting. Therefore, one cannot exclude the possibility that the training itself is a source of stress. In this study, we explored the effects of medical positive reinforcement training on salivary cortisol in two groups of captive ape species, orangutans and bonobos, which were familiar to this procedure. Furthermore, we successfully biologically validated the salivary cortisol assay, which had already been validated for bonobos, for orangutans. For the biological validation, we found that cortisol levels in orangutan saliva collected during baseline conditions were lower than in samples collected during three periods that were potentially stressful for the animals. However, we did not find significant changes in salivary cortisol during medical positive reinforcement training for either bonobos or orangutans. Therefore, for bonobos and orangutans with previous exposure to medical PRT, the procedure is not stressful. Thus, medical PRT provides a helpful tool for the captive management of the two species.

  13. The effect of motivation and positive affect on ego depletion: Replenishment versus release mechanism.

    PubMed

    Zhu, Ze; Li, Jian; Zhang, Bo; Li, Ye; Zhang, Houcan

    2015-11-12

    In this study, 2 experiments were conducted to investigate whether motivation and positive affect can alleviate ego depletion and to elucidate their possible mechanisms. In Experiment 1, a crossing-out-letter task was adapted to reach an ego depletion state for Chinese participants. Participants were then randomly assigned to the extrinsic motivation group, the positive affect group or the depletion control group. After the experimental treatment, a dumbbell task was used to measure participants' remaining self-regulatory resources. The results showed that participants in the motivation and positive affect groups performed better on the dumbbell task than participants in the depletion control group. Experiment 2 was similar to Experiment 1 except that participants were asked to perform an additional unexpected dumbbell task after a neutral video following the above procedure. The results of Experiment 1 were replicated; however, participants' performance on the additional dumbbell task differed. The positive affect group performed better than the depletion control group, indicating an increase in self-regulatory resources and thus supporting the replenishment effect of positive affect. No significant difference was found between the motivation group and the depletion control group.

  14. The effect of quadriceps muscle fatigue on position matching at the knee.

    PubMed

    Givoni, Nathan J; Pham, Tuan; Allen, Trevor J; Proske, Uwe

    2007-10-01

    This is a report of the effects of exercise on position matching at the knee. Young adult subjects were required to step down a set of stairs (792 steps), representing eccentric-biased exercise of the quadriceps muscle, or step up them, concentric-biased exercise. Immediately after eccentric exercise subjects showed a mean force drop of 28% (+/- 6%, s.e.m.) of the control value in their exercised quadriceps muscle, which was accompanied by 4.8 deg (+/- 0.8 deg) of error between reference and matching legs in a position matching task at the knee. Similarly concentric exercise was followed by a force drop of 15% (+/- 3%) and matching errors of 3.7 deg (+/- 0.4 deg). These effects were significant. The direction of the errors suggested that subjects perceived their exercised muscles to be longer that they actually were. This finding was not consistent with the hypothesis that the increase in effort required to support the leg after fatigue from exercise was responsible for the errors. It is hypothesized that position sense in an unsupported leg arises, in part, from operation of an internal forward model. When the motor command is increased to compensate for the effects of fatigue, the comparison between predicted and actual feedback from quadriceps leads to the impression that the muscle is longer than it actually is. The exercise effects on proprioception may have implications for sports injuries and for evaluation of the factors leading to falls in the elderly.

  15. Disentangling the Origin of the Kok Effect Using Position Specific Glucose Labeling in Sunflower Leaves

    NASA Astrophysics Data System (ADS)

    Gauthier, P. P.; Bender, M. L.; Saenz, N.

    2015-12-01

    In plants, leaf mitochondrial respiratory CO2 release is inhibited by light. Bessel Kok first demonstrated this inhibition in 1948. Based on curves of CO2 assimilation vs irradiance, it is understood that respiration is maximal in the dark. It then frequently decreases linearly with irradiance until reaching some value around the compensation point, beyond which it is constant. CO2 released by mitochondrial respiration is the result of decarboxylation through pyruvate dehydrogenase (PDH), the tricarboxylic acid pathway (TCAP) and the oxydative pentose phosphate pathway (OPPP). The overall activity of these three reactions is reduced by light. However, their individual contributions to the Kok effect are unknown. We measured the rate of decarboxylation of glucose, position-specifically labeled with 13C, to evaluate the participation of PDH, TCAP and OPPP in the Kok effect of sunflower. Leaves were fed with labeled glucose through their transpiration stream. The δ13C of the CO2 released by the leaf was then measured as a function of irradiance. The results showed that the inhibition of the decarboxylation of carbon positions 3 and 4 in glucose is at the origin of the Kok effect. These are the positions of carbon atoms decarboxylated by PDH. In addition, the rate of decarboxylation of position 1 was not different in the light and in the dark. Thus OPPP plays no role in the Kok effect in sunflower leaves. This work improves our current understanding of leaf mitochondrial respiratory metabolism in the light. Invoking the Kok effect in plant physiology models should improve our ability to simulate carbon fluxes of terrestrial ecosystems.

  16. The relative position priming effect depends on whether letters are vowels or consonants.

    PubMed

    Duñabeitia, Jon Andoni; Carreiras, Manuel

    2011-09-01

    The relative position priming effect is a type of subset priming in which target word recognition is facilitated as a consequence of priming the word with some of its letters, maintaining their relative position (e.g., csn as a prime for casino). Five experiments were conducted to test whether vowel-only and consonant-only subset primes contribute equally to this effect. Experiment 1 revealed that this subset priming effect emerged when primes were composed exclusively of consonants, compared with vowel-only primes (csn-casino vs. aia-animal). Experiment 2 tested the impact of letter frequency in this asymmetry. Subset priming effects were obtained for both high- and low-frequency consonants but not for vowels, which rules out a letter frequency explanation. Experiment 3 tested the role of phonology and its contribution to the priming effects observed, by decreasing the prime duration. The results showed virtually the same effects as in the previous experiments. Finally, Experiments 4 and 5 explored the influence of repeated letters in the primes on the magnitude of the priming effects obtained for consonant and vowel subset primes (iuo-dibujo and aea-madera vs. mgn-imagen and rtr-frutero). Again, the results confirmed the priming asymmetry. We propose that a functional distinction between consonants and vowels, mainly based on the lexical constraints imposed by each of these types of letters, might provide an explanation for the whole set of results.

  17. Relationship between the adjuvant and cytotoxic effects of the positive charges and polymerization in liposomes.

    PubMed

    Gasparri, Julieta; Speroni, Lucía; Chiaramoni, Nadia Silvia; del Valle Alonso, Silvia

    2011-06-01

    Vaccine development today encounters a main obstacle, which is the need for effective adjuvants suitable for clinical trials. Aluminum salts, discovered 70 years ago and, very recently, MF59, are the only types of adjuvants currently used in vaccines licensed by the U.S. Food and Drug Administration. Liposomes represent an alternative approach to vaccine adjuvants. In this article, we describe the inflammatory response and biological effect of polymerization and the addition of positive charges in liposome formulations. Nonpolymerized cationic (NP(+)) liposomes significantly reduce metabolism in Vero cells after 24 hours. Correspondingly, both NP(+) and polymerized cationic (P(+)) liposomes reduce cell viability following a 48-hour incubation. Similar results were obtained with cells from the peritoneal cavities of mice. Paradoxically, those liposomes that presented clearly cytostatic or cytotoxic effects in vitro stimulated metabolism and had a mitogenic effect in vivo. Finally, the adjuvant effect was tested by immunization in BALB/c mice. The major effect was obtained with NP(+) liposomes. Accordingly, we also demonstrated that NP(+) liposomes injected into the dermis produced an outstanding inflammatory reaction, showing the histopathological characteristics of an inoculation granuloma. Thus, positive charge would play an important role in the immunoadjuvant effect of liposomes by conferring them cytotoxic capacity.

  18. Solvation effects on the band edge positions of photocatalysts from first principles.

    PubMed

    Ping, Yuan; Sundararaman, Ravishankar; Goddard, William A

    2015-11-11

    The band edge positions of photocatalysts relative to the redox potentials of water play an important role in determining the efficiency of photoelectrochemical cells. These band positions depend on the structure of the solid-liquid interface, but direct ab initio molecular dynamics calculations of these interfaces, while expected to be accurate, are too computationally demanding for high-throughput materials screening. Thus rapid theoretical screening of new photocatalyst materials requires simplified continuum solvation models that are suitable for treating solid-liquid interfaces. In this paper, we evaluate the accuracy of the recently developed CANDLE and SaLSA continuum solvation models for predicting solvation effects on the band positions of several well-studied surfaces [Si(111), TiO2(110), IrO2(110) and WO3(001)] in water. We find that the solvation effects vary considerably, ranging from <0.5 eV for hydrophobic surfaces, 0.5-1 eV for many hydrophilic oxide surfaces, to ∼2 eV for oxygen-deficient surfaces. The solvation model predictions are in excellent agreement (within ∼0.1 eV) with ab initio molecular dynamics results where available, and in good agreement (within ∼0.2-0.3 eV) with experimental measurements. We also predict the energetics for surface oxygen vacancies and their effect on the band positions of the hydrated WO3(001) surface, leading to an explanation for why the solvation shift observed experimentally is substantially larger than predicted for the ideal surface. Based on the correlation between solvation shift and the type of surface and solvent, we suggest approaches to engineer the band positions of surfaces in aqueous and non-aqueous solutions.

  19. Positive emotional context eliminates the framing effect in decision-making.

    PubMed

    Cassotti, Mathieu; Habib, Marianne; Poirel, Nicolas; Aïte, Ania; Houdé, Olivier; Moutier, Sylvain

    2012-10-01

    Dual-process theories have suggested that emotion plays a key role in the framing effect in decision-making. However, little is known about the potential impact of a specific positive or negative emotional context on this bias. We investigated this question with adult participants using an emotional priming paradigm. First, participants were presented with positive or negative affective pictures (i.e., pleasant vs. unpleasant photographs). Afterward, participants had to perform a financial decision-making task that was unrelated to the pictures previously presented. The results revealed that the presentation framed in terms of gain or loss no longer affected subjects' decision-making following specific exposure to emotionally pleasant pictures. Interestingly, a positive emotional context did not globally influence risk-taking behavior but specifically decreased the risk propensity in the loss frame. This finding confirmed that a positive emotional context can reduce loss aversion, and it strongly reinforced the dual-process view that the framing effect stems from an affective heuristic belonging to intuitive System 1.

  20. Shoe cleat position during cycling and its effect on subsequent running performance in triathletes.

    PubMed

    Viker, Tomas; Richardson, Matt X

    2013-01-01

    Research with cyclists suggests a decreased load on the lower limbs by placing the shoe cleat more posteriorly, which may benefit subsequent running in a triathlon. This study investigated the effect of shoe cleat position during cycling on subsequent running. Following bike-run training sessions with both aft and traditional cleat positions, 13 well-trained triathletes completed a 30 min simulated draft-legal triathlon cycling leg, followed by a maximal 5 km run on two occasions, once with aft-placed and once with traditionally placed cleats. Oxygen consumption, breath frequency, heart rate, cadence and power output were measured during cycling, while heart rate, contact time, 200 m lap time and total time were measured during running. Cardiovascular measures did not differ between aft and traditional cleat placement during the cycling protocol. The 5 km run time was similar for aft and traditional cleat placement, at 1084 ± 80 s and 1072 ± 64 s, respectively, as was contact time during km 1 and 5, and heart rate and running speed for km 5 for the two cleat positions. Running speed during km 1 was 2.1% ± 1.8 faster (P < 0.05) for the traditional cleat placement. There are no beneficial effects of an aft cleat position on subsequent running in a short distance triathlon.

  1. Musculoskeletal loading during the round-off in female gymnastics: the effect of hand position.

    PubMed

    Farana, Roman; Jandacka, Daniel; Uchytil, Jaroslav; Zahradnik, David; Irwin, Gareth

    2014-06-01

    Chronic elbow injuries from tumbling in female gymnastics present a serious problem for performers. This research examined how the biomechanical characteristics of impact loading and elbow kinematics and kinetics change as a function of technique selection. Seven international-level female gymnasts performed 10 trials of the round-off from a hurdle step to flic-flac with 'parallel' and 'T-shape' hand positions. Synchronized kinematic (3D-automated motion analysis system; 247 Hz) and kinetic (two force plates; 1,235 Hz) data were collected for each trial. Wilcoxon non-parametric test and effect-size statistics determined differences between the hand positions examined in this study. Significant differences (p < 0.05) and large effect sizes (ES > 0.8) were observed for peak vertical ground reaction force (GRF), anterior-posterior GRF, resultant GRF, loading rates of these forces and elbow joint angles, and internal moments of force in sagittal, transverse, and frontal planes. In conclusion, the T-shape hand position reduces vertical, anterior-posterior, and resultant contact forces and has a decreased loading rate indicating a safer technique for the round-off. Significant differences observed in joint elbow moments highlighted that the T-shape position may prevent overloading of the joint complex and consequently reduce the potential for elbow injury.

  2. A biphasic hyperelastic model for the analysis of fluid and mass transport in brain tissue.

    PubMed

    García, José Jaime; Smith, Joshua H

    2009-02-01

    A biphasic hyperelastic finite element model is proposed for the description of the mechanical behavior of brain tissue. The model takes into account finite deformations through an Ogden-type hyperelastic compressible function and a hydraulic conductivity dependent on deformation. The biphasic equations, implemented here for spherical symmetry using an updated Lagrangian algorithm, yielded radial coordinates and fluid velocities that were used with the convective-diffusive equation in order to predict mass transport in the brain. Results of the model were equal to those of a closed-form solution under infinitesimal deformations, however, for a wide range of material parameters, the model predicted important increments in the infusion sphere, reductions of the fluid velocities, and changes in the species content distribution. In addition, high localized deformation and stresses were obtained at the infusion sphere. Differences with the infinitesimal solution may be mainly attributed to geometrical nonlinearities related to the increment of the infusion sphere and not to material nonlinearities.

  3. Biphasic catalysis using amphiphilic polyphenols-chelated noble metals as highly active and selective catalysts

    PubMed Central

    Mao, Hui; Yu, Hong; Chen, Jing; Liao, Xuepin

    2013-01-01

    In the field of catalysis, it is highly desired to develop novel catalysts that combine the advantages of both homogeneous and heterogeneous catalysts. Here we disclose that the use of plant pholyphenol as amphiphilic large molecule ligand/stabilizer allows for the preparation of noble metal complex and noble metal nanoparticle catalysts. These catalysts are found to be highly selective and active in aqueous-organic biphasic catalysis of cinnamaldehyde and quinoline, and can be reused at least 3 times without significant loss of activity. Moreover, the catalytic activity and reusability of the catalysts can be rationally controlled by simply adjusting the content of polyphenols in the catalysts. Our strategy may be extended to design a wide range of aqueous-organic biphasic catalysis system. PMID:23863916

  4. Formation of a Fluorous/Organic Biphasic Supramolecular Octopus Assembly for Enhanced Porphyrin Phosphorescence in Air

    DOE PAGES

    Yang, Chi; Arvapally, Ravi K.; Tekarli, Sammer M.; ...

    2015-03-03

    The trinuclear triangle-shaped system [tris{3,5-bis(heptafluoropropyl)-1,2,4-triazolatosilver(I)}] (1) and the multi-armed square-shaped metalloporphyrin PtOEP or the free porphyrin base H2OEP serve as excellent octopus hosts (OEP=2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine). Coupling of the fluorous/organic molecular octopi 1 and H2OEP or PtOEP by strong quadrupole-quadrupole and metal- interactions affords the supramolecular assemblies [1PtOEP] or [1H(2)OEP] (2a), which feature nanoscopic cavities surrounding the upper triangular and lower square cores. The fluorous/organic biphasic configuration of [1PtOEP] leads to an increase in the phosphorescence of PtOEP under ambient conditions. Guest molecules can be included in the biphasic double-octopus assembly in three different site-selective modes.

  5. Tracking performance of unbalanced QPSK demodulators. II - Biphase Costas loop with active arm filters

    NASA Technical Reports Server (NTRS)

    Simon, M. K.

    1978-01-01

    In a Costas loop study for biphase modulation conducted by Simon and Lindsey (1977), it was demonstrated that considerable improvement in tracking performance could be obtained by employing active arm filters of the integrate-and-dump type as opposed to passive arm filters. An investigation is conducted concerning the possibility to obtain a similar performance improvement for an unbalanced quadriphase-shift-keying (QPSK) modulation. It is found that the biphase Costas loop can be used as an efficient demodulator of QPSK in cases in which the ratio of data rates is of the same order of magnitude as the inverse of the power ratio. These cases involve approximately equal signal energies in the two channels.

  6. A biphasic parameter estimation method for quantitative analysis of dynamic renal scintigraphic data

    NASA Astrophysics Data System (ADS)

    Koh, T. S.; Zhang, Jeff L.; Ong, C. K.; Shuter, B.

    2006-06-01

    Dynamic renal scintigraphy is an established method in nuclear medicine, commonly used for the assessment of renal function. In this paper, a biphasic model fitting method is proposed for simultaneous estimation of both vascular and parenchymal parameters from renal scintigraphic data. These parameters include the renal plasma flow, vascular and parenchymal mean transit times, and the glomerular extraction rate. Monte Carlo simulation was used to evaluate the stability and confidence of the parameter estimates obtained by the proposed biphasic method, before applying the method on actual patient study cases to compare with the conventional fitting approach and other established renal indices. The various parameter estimates obtained using the proposed method were found to be consistent with the respective pathologies of the study cases. The renal plasma flow and extraction rate estimated by the proposed method were in good agreement with those previously obtained using dynamic computed tomography and magnetic resonance imaging.

  7. Mesenchymal stem cells combined with biphasic calcium phosphate ceramics promote bone regeneration.

    PubMed

    Livingston, T L; Gordon, S; Archambault, M; Kadiyala, S; McIntosh, K; Smith, A; Peter, S J

    2003-03-01

    The reconstruction and repair of large bone defects, resulting from trauma, cancer or metabolic disorders, is a major clinical challenge in orthopaedics. Clinically available biological and synthetic grafts have clear limitations that necessitate the development of new graft materials and/or strategies. Human mesenchymal stem cells (MSCs), obtained from the adult bone marrow, are multipotent cells capable of differentiating into various mesenchymal tissues. Of particular interest is the ability of these cells to differentiate into osteoblasts, or bone-forming cells. At Osiris, we have extensively characterized MSCs and have demonstrated MSCs can induce bone repair when implanted in vivo in combination with a biphasic calcium phosphate, specifically hydroxyapatite/tricalcium phosphate. This article reviews previous and current studies utilizing mesenchymal stem cells and biphasic calcium phosphates in bone repair.

  8. Biphasic Kinetic Behavior of Nitrate Reductase from Heterocystous, Nitrogen-Fixing Cyanobacteria 1

    PubMed Central

    Martin-Nieto, José; Flores, Enrique; Herrero, Antonia

    1992-01-01

    Nitrate reductase activity from filamentous, heterocyst-forming cyanobacteria showed a biphasic kinetic behavior with respect to nitrate as the variable substrate. Two kinetic components were detected, the first showing a higher affinity for nitrate (Km, 0.05-0.25 mm) and a lower catalytic activity and the second showing a lower affinity for nitrate (Km, 5-25 mm) and a higher (3- to 5-fold) catalytic activity. In contrast, among unicellular cyanobacteria, most representatives studied exhibited a monophasic, Michaelis-Menten kinetic pattern for nitrate reductase activity. Biphasic kinetics remained unchanged with the use of different assay conditions (i.e. cell disruption or permeabilization, two different electron donors) or throughout partial purification of the enzyme. PMID:16652939

  9. A method for separating water soluble organics from a process stream by aqueous biphasic extraction

    SciTech Connect

    Chaiko, David J.; Mego, William A.

    1997-12-01

    The present invention relates to a method for separating water-miscible organic species from a process stream by aqueous biphasic extraction. In particular, the method includes extracting the organic species into a polymer-rich phase of an aqueous biphase system in which the process stream comprises the salt-rich phase, and, next, separating the polymer from the extracted organic species by contacting the loaded, polymer-rich phase with a water-immiscible organic phase. Alternatively, the polymer can be separated from the extracted organic species by raising the temperature of the loaded, polymer-rich phase above the cloud point, such that the polymer and the water-soluble organic species separate into two distinct aqueous phases. In either case, a substantially salt-free, concentrated aqueous solution containing the organic species is recovered.

  10. Origin and correction of magnetic field inhomogeneity at the interface in biphasic NMR samples.

    PubMed

    Martin, Bryan T; Chingas, G C; McDougal, Owen M

    2012-05-01

    The use of susceptibility matching to minimize spectral distortion of biphasic samples layered in a standard 5 mm NMR tube is described. The approach uses magic angle spinning (MAS) to first extract chemical shift differences by suppressing bulk magnetization. Then, using biphasic coaxial samples, magnetic susceptibilities are matched by titration with a paramagnetic salt. The matched phases are then layered in a standard NMR tube where they can be shimmed and examined. Linewidths of two distinct spectral lines, selected to characterize homogeneity in each phase, are simultaneously optimized. Two-dimensional distortion-free, slice-resolved spectra of an octanol/water system illustrate the method. These data are obtained using a 2D stepped-gradient pulse sequence devised for this application. Advantages of this sequence over slice-selective methods are that acquisition efficiency is increased and processing requires only conventional software.

  11. Deriving sulfamethoxazole dissipation endpoints in pasture soils using first order and biphasic kinetic models.

    PubMed

    Srinivasan, Prakash; Sarmah, Ajit K; Rohan, Maheswaran

    2014-08-01

    Single first-order (SFO) kinetic model is often used to derive the dissipation endpoints of an organic chemical in soil. This model is used due to its simplicity and requirement by regulatory agencies. However, using the SFO model for all types of decay pattern could lead to under- or overestimation of dissipation endpoints when the deviation from first-order is significant. In this study the performance of three biphasic kinetic models - bi-exponential decay (BEXP), first-order double exponential decay (FODED), and first-order two-compartment (FOTC) models was evaluated using dissipation datasets of sulfamethoxazole (SMO) antibiotic in three different soils under varying concentration, depth, temperature, and sterile conditions. Corresponding 50% (DT50) and 90% (DT90) dissipation times for the antibiotics were numerically obtained and compared against those obtained using the SFO model. The fit of each model to the measured values was evaluated based on an array of statistical measures such as coefficient of determination (R(2)adj), root mean square error (RMSE), chi-square (χ(2)) test at 1% significance, Bayesian Information Criteria (BIC) and % model error. Box-whisker residual plots were also used to compare the performance of each model to the measured datasets. The antibiotic dissipation was successfully predicted by all four models. However, the nonlinear biphasic models improved the goodness-of-fit parameters for all datasets. Deviations from datasets were also often less evident with the biphasic models. The fits of FOTC and FODED models for SMO dissipation datasets were identical in most cases, and were found to be superior to the BEXP model. Among the biphasic models, the FOTC model was found to be the most suitable for obtaining the endpoints and could provide a mechanistic explanation for SMO dissipation in the soils.

  12. Electronic and structural characteristics of zinc-blende wurtzite biphasic homostructure GaN nanowires

    DOE PAGES

    Jacobs, Benjamin W.; Ayres, Virginia M.; Petkov, Mihail P.; ...

    2007-04-07

    Here, we report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High-resolution transmission electron microscopy was used to identify distinct wurtzite and zinc-blende crystalline phases within single nanowires through the use of selected area electron diffraction, electron dispersive spectroscopy, electron energy loss spectroscopy, and fast Fourier transform techniques. A mechanism for growth is identified.

  13. Nitric oxide interacts with salicylate to regulate biphasic ethylene production during the hypersensitive response.

    PubMed

    Mur, Luis A J; Laarhoven, Lucas J J; Harren, Frans J M; Hall, Michael A; Smith, Aileen R

    2008-11-01

    C(2)H(4) is associated with plant defense, but its role during the hypersensitive response (HR) remains largely uncharacterized. C(2)H(4) production in tobacco (Nicotiana tabacum) following inoculation with HR-eliciting Pseudomonas syringae pathovars measured by laser photoacoustic detection was biphasic. A first transient rise (C(2)H(4)-I) occurred 1 to 4 h following inoculation with HR-eliciting, disease-forming, and nonpathogenic strains and also with flagellin (flg22). A second (avirulence-dependent) rise, at approximately 6 h (C(2)H(4)-II), was only seen with HR-eliciting strains. Tobacco leaves treated with the C(2)H(4) biosynthesis inhibitor, aminoethoxyvinylglycine, suggested that C(2)H(4) influenced the kinetics of a HR. Challenging salicylate hydroxylase-expressing tobacco lines and tissues exhibiting systemic acquired resistance suggested that C(2)H(4) production was influenced by salicylic acid (SA). Disrupted expression of a C(2)H(4) biosynthesis gene in salicylate hydroxylase tobacco plants implicated transcriptional control as a mechanism through which SA regulates C(2)H(4) production. Treating leaves to increase oxidative stress or injecting with SA initiated monophasic C(2)H(4) generation, but the nitric oxide (NO) donor sodium nitroprusside initiated biphasic rises. To test whether NO influenced biphasic C(2)H(4) production during the HR, the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester was coinoculated with the avirulent strain of P. syringae pv phaseolicola into tobacco leaves. The first transient C(2)H(4) rise appeared to be unaffected by N(G)-nitro-L-arginine methyl ester, but the second rise was reduced. These data suggest that NO and SA are required to generate the biphasic pattern of C(2)H(4) production during the HR and may influence the kinetics of HR formation.

  14. A numerical method for biphasic curve fitting with a programmable calculator.

    PubMed

    Ristanović, D; Ristanović, D; Malesević, J; Milutinović, B

    1982-01-01

    Elimination kinetics of bromsulphalein (BSP) after a single injection into the circulation of rats were examined by means of a four-compartment model. BSP plasma concentrations were measured colorimetrically. A program written for the Texas Instruments TI-59 programmable calculator is presented, which will calculate the fractional blood clearance of BSP using an iteration procedure. A simple method of fitting biphasic decay curves to experimental data is also proposed.

  15. Evidence that the positive inotropic effects of the alkylxanthines are not due to adenosine receptor blockade.

    PubMed Central

    Collis, M. G.; Keddie, J. R.; Torr, S. R.

    1984-01-01

    We investigated the possibility that the positive inotropic effects of the alkylxanthines are due to adenosine receptor blockade. The potency of 8-phenyltheophylline, theophylline and enprofylline as adenosine antagonists was assessed in vitro, using the guinea-pig isolated atrium, and in vivo, using the anaesthetized dog. The order of potency of the alkylxanthines as antagonists of the negative inotropic response to 2-chloroadenosine in vitro, and of the hypotensive response to adenosine in vivo was 8-phenyltheophylline greater than theophylline greater than enprofylline. The order of potency of the alkylxanthines as positive inotropic and chronotropic agents in the anaesthetized dog was enprofylline greater than theophylline greater than 8-phenyltheophylline. The results of this study indicate that the inotropic effects of the alkylxanthines in the anaesthetized dog are not due to adenosine receptor blockade. PMID:6322898

  16. Position effect variegation of an acid phosphatase gene in Drosophila melanogaster.

    PubMed

    Frisardi, M C; MacIntyre, R J

    1984-01-01

    X-ray mutagenesis has produced a series of deficiencies in a duplication of part of the third chromosome containing the acid phosphatase gene (Acph-1) in Drosophila melanogaster. In one of these deficiencies, Acph-1 is shown to be undergoing position effect variegation. Naturally occurring electrophoretic variants of the enzyme were used to visualize and determine quantitatively the extent of variegation of the allele which is cis to the heterochromatic breakpoint. Alteration of genotypic background and temperature provided further evidence for position effect. Rocket immunoelectrophoresis was used to correlate the levels of acid phosphatase activity and protein in flies containing the deficiency. A novel result indicates that the variegation is not the consequence of an averaging of active and inactive cells, but rather due to a quantitative alteration of gene activity within at least some individual cells.

  17. Air Purification Effect of Positively and Negatively Charged Ions Generated by Discharge Plasma at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Nishikawa, Kazuo; Nojima, Hideo

    2001-08-01

    In this paper, the air purification effect of positively and negatively charged ions generated by discharge plasma at atmospheric pressure is reported. We have developed a novel ion generation device which consists of a cylindrical glass tube and attached inner and outer mesh electrodes. With the application of AC voltage between the electrodes, positively charged ions and negatively charged ions have been generated at atmospheric pressure. The ion densities of 3.0× 104--7.0× 104 counts/cm3 have been obtained with the AC voltage of 1.8-2.3 kV (effective value). We have examined the air purification properties of this device. By the operation of this device, the initial oxygen nitride (NO) density of 10 ppm in 1 m3 (in cigarette smoke) was decreased to 1 ppm after 30 min. The number of suspended germs in air has been significantly reduced by the use of this type of ion generation device.

  18. Aqueous Biphasic Systems Based on Salting-Out Polyethylene Glycol or Ionic Solutions: Strategies for Actinide or Fission Product Separations

    SciTech Connect

    Rogers, Robin D.; Gutowski, Keith E.; Griffin, Scott T.; Holbrey, John D.

    2004-03-29

    Aqueous biphasic systems can be formed by salting-out (with kosmotropic, waterstructuring salts) water soluble polymers (e.g., polyethylene glycol) or aqueous solutions of a wide range of hydrophilic ionic liquids based on imidazolium, pyridinium, phosphonium and ammonium cations. The use of these novel liquid/liquid biphases for separation of actinides or other fission products associated with nuclear wastes (e.g., pertechnetate salts) has been demonstrated and will be described in this presentation.

  19. The Effect of Body Position on Physiological Factors that Contribute to Obstructive Sleep Apnea

    PubMed Central

    Joosten, Simon A.; Edwards, Bradley A.; Wellman, Andrew; Turton, Anthony; Skuza, Elizabeth M.; Berger, Philip J.; Hamilton, Garun S.

    2015-01-01

    Study objectives: Obstructive sleep apnea (OSA) resolves in lateral sleep in 20% of patients. However, the effect of lateral positioning on factors contributing to OSA has not been studied. We aimed to measure the effect of lateral positioning on the key pathophysiological contributors to OSA including lung volume, passive airway anatomy/collapsibility, the ability of the airway to stiffen and dilate, ventilatory control instability (loop gain), and arousal threshold. Design: Non-randomized single arm observational study. Setting: Sleep laboratory. Patients/participants: 20 (15M, 5F) continuous positive airway pressure (CPAP)-treated severe OSA patients. Interventions: Supine vs. lateral position. Measurements: CPAP dial-downs performed during sleep to measure: (i) Veupnea: asleep ventilatory requirement, (ii) passive V0: ventilation off CPAP when airway dilator muscles are quiescent, (iii) Varousal: ventilation at which respiratory arousals occur, (iv) active V0: ventilation off CPAP when airway dilator muscles are activated during sleep, (v) loop gain: the ratio of the ventilatory drive response to a disturbance in ventilation, (vi) arousal threshold: level of ventilatory drive which leads to arousal, (vii) upper airway gain (UAG): ability of airway muscles to restore ventilation in response to increases in ventilatory drive, and (viii) pharyngeal critical closing pressure (Pcrit). Awake functional residual capacity (FRC) was also recorded. Results: Lateral positioning significantly increased passive V0 (0.33 ± 0.76L/min vs. 3.56 ± 2.94L/min, P < 0.001), active V0 (1.10 ± 1.97L/min vs. 4.71 ± 3.08L/min, P < 0.001), and FRC (1.31 ± 0.56 L vs. 1.42 ± 0.62 L, P = 0.046), and significantly decreased Pcrit (2.02 ± 2.55 cm H2O vs. −1.92 ± 3.87 cm H2O, P < 0.001). Loop gain, arousal threshold, Varousal, and UAG were not significantly altered. Conclusions: Lateral positioning significantly improves passive airway anatomy/collapsibility (passive V0, pharyngeal

  20. Effective population size is positively correlated with levels of adaptive divergence among annual sunflowers.

    PubMed

    Strasburg, Jared L; Kane, Nolan C; Raduski, Andrew R; Bonin, Aurélie; Michelmore, Richard; Rieseberg, Loren H

    2011-05-01

    The role of adaptation in the divergence of lineages has long been a central question in evolutionary biology, and as multilocus sequence data sets have become available for a wide range of taxa, empirical estimates of levels of adaptive molecular evolution are increasingly common. Estimates vary widely among taxa, with high levels of adaptive evolution in Drosophila, bacteria, and viruses but very little evidence of widespread adaptive evolution in hominids. Although estimates in plants are more limited, some recent work has suggested that rates of adaptive evolution in a range of plant taxa are surprisingly low and that there is little association between adaptive evolution and effective population size in contrast to patterns seen in other taxa. Here, we analyze data from 35 loci for six sunflower species that vary dramatically in effective population size. We find that rates of adaptive evolution are positively correlated with effective population size in these species, with a significant fraction of amino acid substitutions driven by positive selection in the species with the largest effective population sizes but little or no evidence of adaptive evolution in species with smaller effective population sizes. Although other factors likely contribute as well, in sunflowers effective population size appears to be an important determinant of rates of ad