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Sample records for 50mm tris-hcl buffer

  1. Bio resorbability of the modified hydroxyapatite in Tris-HCL buffer

    NASA Astrophysics Data System (ADS)

    Golovanova, O. A.; Izmailov, R. R.; Ghyngazov, S. A.

    2016-02-01

    The solubility of carbonated hydroxyapatite powders and granulated carbonated hydroxyapatite produced from the synovial biofluid model solution has been studied. The kinetic characteristics of dissolution were determined. It was found that the solubility of carbonated hydroxyapatite is higher as compared to that of hydroxyapatite. The impact of the organic matrix on the rate of sample dissolution was revealed. For HA-gelatin composites, as the gelatin concentration grows, the dissolution rate becomes greater, and a sample of 6.0 g / L concentration has higher resorbability. The results of the research can be used to study the kinetics of dissolution and the biocompatibility of ceramic materials for medicine, namely for reconstructive surgery, dentistry, and development of drug delivery systems.

  2. Corrigendum to "The partial molal volume and compressibility of Tris and Tris-HCl in water and 0.725 m NaCl as a function of temperature," [Deep-Sea Res. I 104 (2015) 41-51

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carmen; Huang, Fen; Millero, Frank J.

    2016-08-01

    The authors of Rodriguez et al. (2015) regret some incorrect values published in Tables 8 and 9. The values shown in Table 8 for V bar 0 and κ bar 0 of Tris-HCl in 0.725 m NaCl, and the values shown in Table 9 for ΔV and Δκ in 0.725 m NaCl were from an earlier calculation that was later revised. The correct values are provided below. Importantly, all other values printed in the manuscript are correct (e.g., coefficients in Tables 5-7, Table 8, Eqs. (22)-(25)). The discussions and conclusions made in this paper are not affected by these changes. The authors would like to acknowledge Yui Takeshita of Stanford University for bringing this to our attention. We apologize for any inconvenience caused.

  3. SSC 50 mm collider dipole cryostat single tube support post conceptual design and analysis

    SciTech Connect

    Nicol, T.H.

    1992-04-01

    This report describes the conceptual design for a support post whose function is identical to that of the current reentrant design, which requires very few modifications to surrounding cryostat components, is thermally equivalent to the current 50 mm support post, and is nearly equivalent structurally. The focus of this work is on a design aimed specifically at application in SSC 50 mm collider dipoles, however, the conceptual design presented here is applicable to other cryogenic systems.

  4. Optimization of buffer solutions to analyze inflammatory cytokines in gingival crevicular fluid by multiplex flow cytometry

    PubMed Central

    Ríos-Lugo, María-Judith; Martin, Conchita; Alarcón, José-Antonio; Esquifino, Ana; Solano, Patricia; Sanz, Mariano

    2015-01-01

    Objective: the aim of this study was to test two buffer solutions in order to attain a reliable and reproducible analysis of inflammatory cytokines (IL-1β, IL-6, TNF-α, OPG, OPN and OC), in gingival crevicular fluid (GCF) by flow cytometry. Material and Methods: GCF samples from healthy volunteers were collected with perio-paper strips and diluted either in phosphate buffered saline (PBS) or Tris-HCl buffer, with and without protease inhibitors (PI). Cytokine immunoassays were carried out by flow cytometry (Luminex Xmap 200) generating standard curves. Results: standards curves generated with the use of phosphate-buffered saline (PBS) demonstrated best adjustment for cytokines IL-1ß, IL-6 and TNF- α levels, when using Tris-HCl (p<0.05). Conclusions: The use of PBS buffer with the addition of PI provided reliable measurements of inflammatory biomarkers in GCF samples of healthy volunteers. Key words:Curve fitting, flow cytometer, immunoassay buffer, crevicular fluid, cytokines. PMID:24880451

  5. Influence of Buffer Composition and Calcium Chloride on GdnHCl Denaturation of Bacillus licheniformis α-Amylase.

    PubMed

    Kandandapani, Salanee; Tan, Cheau Y; Shuib, Adawiyah S; Tayyab, Saad

    2016-01-01

    The influence of buffer composition on the conformational stability of native and calciumdepleted Bacillus licheniformis α-amylase (BLA) was investigated against guanidine hydrochloride (GdnHCl) denaturation using circular dichroism, fluorescence and UV-difference spectroscopy. Differential effect of buffer composition on GdnHCl denaturation of BLA was evident from the magnitude of these spectral signals, which followed the order: sodium phosphate > Tris-HCl > HEPES > MOPS. These effects became more pronounced with calcium-depleted BLA. Sephacryl S-200 gel chromatographic results showed significant BLA aggregation in the presence of 6 M GdnHCl.

  6. Magnetic field measurements of full length 50 mm aperture SSC dipole magnets at Fermilab

    SciTech Connect

    Strait, J.; Bossert, R.; Carson, J.; Delchamps, S.W.; Gourlay, S.; Hanft, R.; Koska, W.; Kuchnir, M.; Lamm, M.J.; Mazur, P.O.; Mokhtarani, A.; Orris, D.; Ozelis, J.; Wake, M. ); Devred, A.; DiMarco, J.; Kuzminski, J.; Puglisi, M.; Tompkins, J.C.; Yu, Y.; Zhao, Y.; Zheng, H. ); Ogitsu, T. (Supe

    1992-09-01

    Thirteen 16 m long, 50 mm aperture SSC dipole magnets, designed jointly by Fermilab, Brookhaven National Laboratory, Lawrence Berkeley Laboratory and the SSC Laboratory, have been built at Fermilab. The first nine magnets have been fully tested to date. The allowed harmonics are systematically shifted from zero by amounts larger than the specification. The unallowed harmonics, with the exception of the skew sextupole, are consistent with zero. The magnet-to-magnet RMS variation of all harmonics is much smaller than the specification.

  7. Temporal arteritis with erythrocyte sedimentation rate <50 mm/h: a clinical reminder

    PubMed Central

    Cheema, Muhammad Raza; Ismaeel, Shakawan M

    2016-01-01

    Temporal arteritis, also known as giant cell arteritis (GCA), is a systemic vasculitis that predominantly involves the temporal arteries. It is a medical emergency and should be treated promptly as it can lead to permanent loss of vision. It is very commonly associated with a raised erythrocyte sedimentation rate (ESR), usually >50 mm/h, one of the essential criteria defined by the American College of Rheumatology classification of GCA. Here, we describe the case of a 73-year-old male presenting with a 2-day history of a sudden onset of a severe left-sided headache, which had the signs and symptoms consistent with GCA but he had an ESR of only 27 mm/h. The patient was urgently treated with prednisolone 60 mg per day, and his symptoms dramatically improved within 24 hours of therapy. Temporal artery biopsy results were consistent with an inflammatory response, and withdrawal of treatment led to a relapse of the symptoms. The patient was slowly tapered off the high steroid dose and is now currently managed on a low steroid dose. We should keep a high index of suspicion for GCA in patients presenting with clinical symptoms of GCA even though the ESR is <50 mm/h as stated in the criteria for GCA diagnosis. PMID:26966355

  8. Design and evaluation of coils for a 50 mm diameter induction coilgun launcher

    SciTech Connect

    Kaye, R.J.; Shokair, I.R.; Wavrik, R.W.; Dempsey, J.F.; Honey, W.E.; Shimp, K.J.; Douglas, G.M.

    1993-12-31

    Coilguns have the ability to provide magnetic pressure to projectiles which results in near constant acceleration. However, to achieve this performance and control projectile hearing, significant constraints are placed on the design of the coils. We are developing coils to produce an effective projectile base pressure of 100 MPa (1kbar) as a step toward reaching base pressures of 200 MPa. The design uses a scalable technology applicable to the entire range of breech to muzzle coils of a multi-stage launcher. This paper presents the design of capacitor-driven coils for launching nominal 50 mm, 350 gram projectiles. Design criteria, constraints, mechanical stress analysis, launcher performance, and test results are discussed.

  9. Design and performance of Sandia's contactless coilgun for 50 mm projectiles

    NASA Astrophysics Data System (ADS)

    Kaye, Ronald J.; Cnare, Eugene C.; Cowan, M.; Duggin, Billy W.; Lipinski, Ronald J.; Marder, Barry M.; Douglas, Gary M.; Shimp, Kenneth J.

    1991-10-01

    A multi-stage, contactless coilgun is being designed to demonstrate the applicability of this technology to accelerate nominal 50 mm (2 inch) diameter projectiles to velocities of 3 km/s. Forty stages of this design (Phase 1 coilgun) will provide a testbed for coil designs and system components while accelerating 200 to 400 gram projectiles to 1 km/s. We have successfully qualified the Phase 1 gun by operating 40 stages at half energy (10 kJ stored/stage) accelerating 340 gram, room-temperature, aluminum-armature projectiles to 406 m/s. We expect to accelerate 200 gram projectiles cooled to -196 C to three times this velocity when operating at full energy. This paper describes the design and performance of the Phase 1 coilgun and includes discussion of coil development, projectile design, capacitor banks, firing system, and integration.

  10. Ultra-Compact Multitip Scanning Probe Microscope with an Outer Diameter of 50 mm

    NASA Astrophysics Data System (ADS)

    Cherepanov, Vasily; Zubkov, Evgeny; Junker, Hubertus; Korte, Stefan; Blab, Marcus; Coenen, Peter; Voigtländer, Bert

    We present a multitip scanning tunneling microscope (STM) where four independent STM units are integrated on a diameter of 50 mm. The coarse positioning of the tips is done under the control of an optical microscope or an SEM in vacuum. The heart of this STM is a new type of piezoelectric coarse approach called Koala Drive which can have a diameter greater than 2.5 mm and a length smaller than 10 mm. Alternating movements of springs move a central tube which holds the STM tip or AFM sensor. This new operating principle provides a smooth travel sequence and avoids shaking which is intrinsically present for nanopositioners based on inertial motion with saw tooth driving signals. Inserting the Koala Drive in a piezo tube for xyz-scanning integrates a complete STM inside a 4 mm outer diameter piezo tube of <10 mm length. The use of the Koala Drive makes the scanning probe microscopy design ultra-compact and accordingly leads to a high mechanical stability. The drive is UHV, low temperature, and magnetic field compatible. The compactness of the Koala Drive allows building a four-tip STM as small as a single-tip STM with a drift of <0.2 nm/min and lowest resonance frequencies of 2.5 (xy) and 5.5 kHz (z). We present examples of the performance of the multitip STM designed using the Koala Drive.

  11. 50 mm Diameter digital DC/pulse neutron generator for subcritical reactor test

    NASA Astrophysics Data System (ADS)

    Li, Gang; Zhang, Zhong-Shuai; Chi, Qian; Liu, Lin-Mao

    2012-11-01

    A 50 mm diameter digital DC/pulse neutron generator was developed with 25 mm ceramic drive-in target neutron tube. It was applied in the subcritical reactor test of China Institute of Atomic Energy (CIAE). The generator can produce neutron in three modes: DC, pulse and multiple pulse. The maximum neutron yield of the generator is 1 × 108 n/s, while the maximum pulse frequency is 10 kHz, and the minimum pulse width is 10 μs. As a remote controlled generator, it is small in volume, easy to be connected and controlled. The tested results indicate that penning ion source has the feature of delay time in glow discharge, and it is easier for glow discharge to happen when switching the DC voltage of penning ion source into pulse. According to these two characteristics, the generator has been modified. This improved generator can be used in many other areas including Prompt Gamma Neutron Activation Analysis (PGNAA), neutron testing and experiment.

  12. Phosphate buffer effects on thermal stability and H2O2-resistance of horseradish peroxidase.

    PubMed

    Asad, Sedigheh; Torabi, Seyed-Fakhreddin; Fathi-Roudsari, Mehrnoosh; Ghaemi, Nasser; Khajeh, Khosro

    2011-05-01

    Horseradish peroxidase (HRP) has attracted intense research interest due to its potential applications in biotechnological fields. However, inadequate stability under prevalent conditions such as elevated temperatures and H(2)O(2) exposure, has limited its industrial application. In this study, stability of HRP was investigated in the presence of different buffer systems (potassium phosphate and Tris-HCl) and additives. It was shown that the concentration of phosphate buffer severely affects enzyme thermostability in a way that in diluted potassium phosphate buffer (10mM) half-life (from 13 to 35 min at 80 °C) and T(m) (from 73 to 77.5 °C) increased significantly. Among additives tested, trehalose had the most thermostabilizing effect. Exploring the role of glycosylation in stabilizing effect of phosphate buffer, non-glycosylated recombinant HRP was also examined for its thermal and H(2)O(2) stability in both diluted and concentrated phosphate buffers. The recombinant enzyme was more thermally stable in diluted buffer in accordance to glycosylated HRP; but interestingly recombinant HRP showed higher H(2)O(2) tolerance in concentrated buffer.

  13. Comparative analyses of universal extraction buffers for assay of stress related biochemical and physiological parameters.

    PubMed

    Han, Chunyu; Chan, Zhulong; Yang, Fan

    2015-01-01

    Comparative efficiency of three extraction solutions, including the universal sodium phosphate buffer (USPB), the Tris-HCl buffer (UTHB), and the specific buffers, were compared for assays of soluble protein, free proline, superoxide radical (O2∙-), hydrogen peroxide (H2O2), and the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR) in Populus deltoide. Significant differences for protein extraction were detected via sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2-DE). Between the two universal extraction buffers, the USPB showed higher efficiency for extraction of soluble protein, CAT, GR, O2∙-, GPX, SOD, and free proline, while the UTHB had higher efficiency for extraction of APX, POD, and H2O2. When compared with the specific buffers, the USPB showed higher extraction efficiency for measurement of soluble protein, CAT, GR, and O2∙-, parallel extraction efficiency for GPX, SOD, free proline, and H2O2, and lower extraction efficiency for APX and POD, whereas the UTHB had higher extraction efficiency for measurement of POD and H2O2. Further comparisons proved that 100 mM USPB buffer showed the highest extraction efficiencies. These results indicated that USPB would be suitable and efficient for extraction of soluble protein, CAT, GR, GPX, SOD, H2O2, O2∙-, and free proline.

  14. Oxidative DNA damage induced by HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) buffer in the presence of Au(III).

    PubMed

    Habib, Ahsan; Tabata, Masaaki

    2004-11-01

    Oxidative DNA damage was investigated by free radicals generated from HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) buffer, which is widely used in biochemical or biological studies, in the presence of Au(III). The effect of free radicals on the DNA damage was ascertained by gel electrophoresis, electron spin resonance (ESR) spectroscopy and circular dichroism (CD) spectroscopy. ESR results indicated the generation of nitrogen-centered cationic free radicals from the HEPES in the presence of Au(III) which cause the DNA damage. No ESR spectra were observed for phosphate, tris(hydroxymethyl)aminomethane (Tris-HCl) and acetate buffers in the presence of Au(III) or for HEPES buffer in the presence of other metal ions such as Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) or [Au(III)(TMPyP)](5+) and [Pd(II)(TMPyP)](4+), where [H(2)(TMPyP)](4+) denotes tetrakis(1-methylpyridium-4-yl)porphyrin. Consequently, no DNA damage was observed for these buffer agents (e.g., phosphate, Tris-HCl or acetate) in the presence of Au(III) or for HEPES in the presence of other metal ions or the metalloporphyrins mentioned above. No detectable inhibitory effect on the DNA damage was observed by using the typical scavengers of reactive oxygen species (ROS) ()OH, O(2)(-) and H(2)O(2). This non-inhibitory effect indicated that no reactive oxygen species were generated during the incubation of DNA with HEPES and Au(III). The drastic change in CD spectra from positive ellipticity to negative ellipticity approximately at 270 nm with increasing concentration of Au(III) also indicated the significant damage of DNA. Only HEPES or Au(III) itself did not damage DNA. A mechanism for the damaging of DNA is proposed.

  15. Kinetic performance of a 50mm long 1.8μm chiral column in supercritical fluid chromatography.

    PubMed

    Berger, Terry A

    2016-08-12

    Reduced plate heights (hr) of <2 were observed for the first time during the chiral separation of enantiomers, on sub-2μm particles with supercritical fluid chromatography (SFC). The enantiomers of trans-stilbene oxide, were separated on a 4.6×50mm, 1.8μm R,R-Whelk-O1 column, with hr as low as 1.93. The plumbing of a commercial SFC instrument was modified to create a low dispersion version. Without the modification performance was considerably worse. vanDeemter like plots of reduced plate height vs. flow rate, for trans-stilbene oxide, indicate that the optimum flow varied with% modifier. On a 4.6×250mm, 5μm R,R- Whelk-O1 column, the optimum flow was >4mL/min for 5% methanol in CO2, decreasing to <2mL/min for 40% methanol (more than a factor of 2). For a 4.6×50mm column packed with 1.8μm particles the optimum appeared to be near, or >5mL/min with 2.5%, 5%, and 10% methanol, decreasing to between 3 and 3.5mL/min at 40% methanol. This is the first time such shifts have been characterized. Since the solutes were the same in all cases, the differences are likely due to changes in solute diffusion coefficients caused by changes in modifier concentration, and pressure. Pump pressure requirements sometimes exceeded 500bar. It is shown that a 5mL/min flow rate is inadequate for use with 1.8μm particles in a 4.6mm ID column format. Instead, it is suggested to decrease the ID of the column to 3mm, where the optimum flow rates are on the order of 2mL/min with decreased tubing variance. Nevertheless, a number of sub-1min chromatograms are presented.

  16. Failure Analysis and Recovery of a 50-mm Highly Elastic Intermetallic NiTi Ball Bearing for an ISS Application

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Howard, S. Adam; Moore, Lewis

    2016-01-01

    Ball bearings used inside the ISS Distillation Assembly centrifuge require superior corrosion and shock resistance to withstand acidic wastewater exposure and heavy spacecraft launch related loads. These requirements challenge conventional steel bearings and provide an ideal pathfinder application for 50-mm bore, deep-groove ball bearings made from the corrosion immune and highly elastic intermetallic material 60NiTi. During early ground testing in 2014 one 60NiTi bearing unexpectedly and catastrophically failed after operating for only 200 hr. A second bearing running on the same shaft was completely unaffected. An investigation into the root cause of the failure determined that an excessively tight press fit of the bearing outer race coupled with NiTi's relatively low elastic modulus were key contributing factors. The proposed failure mode was successfully replicated by experiment. To further corroborate the root cause theory, a successful bearing life test using improved installation practices (selective fitting) was conducted. The results show that NiTi bearings are suitable for space applications provided that care is taken to accommodate their unique material characteristics.

  17. Failure Analysis and Recovery of a 50mm Highly Elastic Intermetallic NiTi Ball Bearing for an ISS Application

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Howard, S. Adam; Moore, Lewis E., III

    2016-01-01

    The ISS Distillation Assembly centrifuge is the pathfinder application for 50mm bore, deep-groove ball bearings made from the highly elastic intermetallic material 60NiTi. Superior corrosion and shock resistance are required to withstand the acidic wastewater exposure and heavy spacecraft launch related loads that challenge conventional steel bearings. During early ground testing one bearing unexpectedly and catastrophically failed after operating for only 200 hours of run time. A second bearing running on the same shaft was completely unaffected. A thorough investigation into the root cause of the failure determined that an excessively tight press-fit of the bearing outer race coupled with NiTis relatively low elastic modulus were key contributing factors. The proposed failure mode was successfully duplicated by experiment. To further corroborate the root cause theory, a successful bearing life test using improved installation practices (selective fitting) was conducted. The results show that NiTi bearings are suitable for space applications provided that care is taken to accommodate their unique material characteristics.

  18. Depth profiling 137Cs and 60Co non-intrusively for a suite of industrial shielding materials and at depths beyond 50 mm.

    PubMed

    Adams, Jamie C; Joyce, Malcolm J; Mellor, Matthew

    2012-07-01

    A phantom has been used to position two radiation sources, separately, when buried under dry-silica sand at depths between 5 and 50 mm. A γ-ray energy spectrum was then measured at every 1 mm depth. Principal component analysis has been conducted, which has led to a non-linear fit being established, allowing the depth of entrainment to be accurately inferred. The technique has been expanded for additional shielding media: water, aggregate and both wet and dry soil. The technique has also been expanded beyond the previous depth constraint of 50 mm.

  19. Role of Human DNA Polymerase and Its Accessory Proteins in Breast Cancer

    DTIC Science & Technology

    2002-04-01

    7.8, 0.25 m sucrose, 0.1 M NaCl, 0.1% Nonidet P-40, 0.1 mm Labeling-Sf9 cells (10’) were grown to exponential stage. Pol 6, cyclin, EGTA, 1 mM EDTA, 1...Tris-HCl, pH dialyzed against TGEED buffer (50 mM Tris-HC1, pH 7.5, 10% glycerol, 7.8, 0.25 m sucrose, 0.5 m NaCl, 0.1% Nonidet P-40, 0.1 mm EGTA, 1...lysed with 300 M1 of Nonidet P-40 buffer gradient of 0-1 m NaCl for 20 min at 1 ml/min. (50 mm Tris-HCl, 1 mm phenylmethylsulfonyl fluoride, 150 mm

  20. Influence of the solvent on the ground- and excited-state buffer-mediated proton-transfer reactions of a xanthenic dye.

    PubMed

    Paredes, Jose M; Crovetto, Luis; Orte, Angel; Alvarez-Pez, Jose M; Talavera, Eva M

    2011-01-28

    The buffer-mediated proton-transfer reactions of the fluorescent xanthenic derivative 9-[1-(2-Methyl-4-methoxyphenyl)]-6-hydroxy-3H-xanthen-3-one (TG-II) have been studied in different aqueous media. We have employed various buffers to investigate the influence of donor/acceptor systems with different anion and/or cation chemical constituents on the kinetic parameters of proton-transfer. The kinetic parameters were recovered both in the ground-state by means of Fluorescence Lifetime Correlation Spectroscopy (FLCS) and in the excited-state by means of Time Correlated Single Photon Counting (TCSPC) and Global Compartmental Analysis (GCA). Both ground- and excited- deprotonation and protonation recovered rate constants in the presence of either phosphate or acetate buffer as donor/acceptor systems were similar. The presence of Tris-HCl buffer does not promote the excited-state proton-transfer (ESPT) reaction. The results indicate the influence of the ions on the ground-state proton-transfer (GSPT) rates and concomitantly on the ESPT reaction. The proton-transfer rate constants recovered here show a trend correlated with the Hofmeister series or the Marcus classification of ions.

  1. Striking Effects of Storage Buffers on Apparent Half-Lives of the Activity of Pseudomonas aeruginosa Arylsulfatase.

    PubMed

    Li, Yuwei; Yang, Xiaolan; Wang, Deqiang; Hu, Xiaolei; Yuan, Mei; Pu, Jun; Zhan, Chang-Guo; Yang, Zhaoyong; Liao, Fei

    2016-08-01

    To obtain the label enzyme for enzyme-linked-immunoabsorbent-assay of two components each time in one well with conventional microplate readers, molecular engineering of Pseudomonas aeruginosa arylsulfatase (PAAS) is needed. To compare thermostability of PAAS/mutants of limited purity, effects of buffers on the half-activity time (t 0.5) at 37 °C were tested. At pH 7.4, PAAS showed non-exponential decreases of activity, with the apparent t 0.5 of ~6.0 days in 50 mM HEPES, but ~42 days in 10 mM sodium borate with >85 % activity after 15 days; protein concentrations in both buffers decreased at slower rates after there were significant decreases of activities. Additionally, the apparent t 0.5 of PAAS was ~14 days in 50 mM Tris-HCl, and ~21 days in 10 mM sodium phosphate. By sodium dodecyl-polyacrylamide gel electrophoresis, the purified PAAS gave single polypeptide; after storage for 14 days at 37 °C, there were many soluble and insoluble fragmented polypeptides in the HEPES buffer, but just one principal insoluble while negligible soluble fragmented polypeptides in the borate buffer. Of tested mutants in the neutral borate buffer, rates for activity decreases and polypeptide degradation were slower than in the HEPES buffer. Hence, dilute neutral borate buffers were favorable for examining thermostability of PAAS/mutants.

  2. Measurement of the mid-infrared Fourier spectroscopic imaging of whole human face by portable apparatus (size: 50*50 mm, weight: 200 g)

    NASA Astrophysics Data System (ADS)

    Qi, Wei; Suzuki, Yo; Fujiwara, Masaru; Saito, Tsubasa; Suzuki, Satoru; Abeygunawardhana, Pradeep K.; Wada, Kenji; Nishiyama, Akira; Ishimaru, Ichiro

    2014-11-01

    In the daily living space, measurement of the biological-substance distributions such as sebum can be realized by the proposed method of imaging-type 2-dimensional Fourier spectroscopy. This method has the strong robustness for mechanical vibrations. So, the spectrometer (size: 50*50mm, weight: 200g) can be produced without anti-vibration mechanism. Moreover, the phase shifter is a core part of the spectrometer, and it is constructed by the low-price bimorph type actuator which is depending on the vibration control of the piezoceramic in proposed method. It is appropriate as the actuator of the phase shifter from the evaluation results of the actuator straightness and position accuracy in the midinfrared region. As we know, the Fourier spectroscopy has a high light utilization efficiency. Therefore, the low price microbolometer can be used as the imaging sensor. So, the low-price (10,000 U.S. dollars), compact and high portability spectrometer can be produced. Furthermore, the much higher position accuracy in the short wavelength region is requested as we know, the phase shift correction method has been proposed. In this paper, high performance evaluations of the portable spectroscopy apparatus have been discussed by using the CO2 laser spectroscopy results in the midinfrared region. Then, the phase shift correction method was explained. At the end, we demonstrated the feasibility of the mid-infrared imaging of whole human faces without active illuminations.

  3. Mono- and polyprotic buffer systems in anion exchange chromatography of influenza virus particles.

    PubMed

    Vajda, Judith; Weber, Dennis; Stefaniak, Sabine; Hundt, Boris; Rathfelder, Tanja; Müller, Egbert

    2016-05-27

    Different ions typically used in downstream processing of biologicals are evaluated for their potential in anion exchange chromatography of an industrially produced, pandemic influenza H1N1 virus. Capacity, selectivity and recovery are investigated based on single step elution parallel chromatography experiments. The inactivated H1N1 feedstream is produced in Madin-Darby Bovine Kidney cells. Interesting effects are found for sodium phosphate and sodium citrate. Both anions are triprotic kosmotropes. Anion exchange chromatography generally offers high scalability to satisfy sudden demands for vaccines, which may occur in case of an emerging influenza outbreak. Appropriate pH conditions for H1N1 adsorption are determined by Zeta potential measurements. The dynamic binding capacity of a salt tolerant polyamine-type resin is up to 6.4 times greater than the capacity of a grafted Q-type resin. Pseudo-affinity interactions of polyamines with the M2 protein of influenza may contribute to the obtained capacity increase. Both resins achieve greater capacity in sodium phosphate buffer compared to Tris/HCl. A recovery of 67% and DNA clearance close to 100% without DNAse treatment are achieved for the Q-type resin. Recovery of the virus from the salt tolerant resin requires the use of polyprotic acids in the elution buffer. 85% of the DNA and 60% of the proteins can be removed by the salt tolerant resin. The presence of sodium phosphate during anion exchange chromatography seems to support stability of the H1N1 particles in presence of hydrophobic cations.

  4. Buffer Biology.

    ERIC Educational Resources Information Center

    Morgan, Kelly

    2000-01-01

    Presents a science experiment in which students test the buffering capacity of household products such as shampoo, hand lotion, fizzies candy, and cola. Lists the standards addressed in this experiment and gives an example of a student lab write-up. (YDS)

  5. Kinetic buffers.

    PubMed

    Alibrandi, Giuseppe; Fabbrizzi, Luigi; Licchelli, Maurizio; Puglisi, Antonio

    2015-01-12

    This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment.

  6. Buffer Zone Fact Sheets

    EPA Pesticide Factsheets

    New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

  7. VIRTUAL FRAME BUFFER INTERFACE

    NASA Technical Reports Server (NTRS)

    Wolfe, T. L.

    1994-01-01

    Large image processing systems use multiple frame buffers with differing architectures and vendor supplied user interfaces. This variety of architectures and interfaces creates software development, maintenance, and portability problems for application programs. The Virtual Frame Buffer Interface program makes all frame buffers appear as a generic frame buffer with a specified set of characteristics, allowing programmers to write code which will run unmodified on all supported hardware. The Virtual Frame Buffer Interface converts generic commands to actual device commands. The virtual frame buffer consists of a definition of capabilities and FORTRAN subroutines that are called by application programs. The virtual frame buffer routines may be treated as subroutines, logical functions, or integer functions by the application program. Routines are included that allocate and manage hardware resources such as frame buffers, monitors, video switches, trackballs, tablets and joysticks; access image memory planes; and perform alphanumeric font or text generation. The subroutines for the various "real" frame buffers are in separate VAX/VMS shared libraries allowing modification, correction or enhancement of the virtual interface without affecting application programs. The Virtual Frame Buffer Interface program was developed in FORTRAN 77 for a DEC VAX 11/780 or a DEC VAX 11/750 under VMS 4.X. It supports ADAGE IK3000, DEANZA IP8500, Low Resolution RAMTEK 9460, and High Resolution RAMTEK 9460 Frame Buffers. It has a central memory requirement of approximately 150K. This program was developed in 1985.

  8. Use of tissue-engineered nerve grafts consisting of a chitosan/poly(lactic-co-glycolic acid)-based scaffold included with bone marrow mesenchymal cells for bridging 50-mm dog sciatic nerve gaps.

    PubMed

    Ding, Fei; Wu, Jian; Yang, Yumin; Hu, Wen; Zhu, Qi; Tang, Xin; Liu, Jie; Gu, Xiaosong

    2010-12-01

    Bone marrow mesenchymal cells (MSCs) have attracted increasing research interest due to their possible use as support cells for nerve tissue-engineering approaches. We developed a novel design of tissue-engineered nerve grafts consisting of a chitosan/poly(lactic-co-glycolic acid) (PLGA)-based neural scaffold included with autologous MSCs. The graft was used as an alternative to nerve autografts for bridging 50-mm-long gaps in dog sciatic nerve, and the repair outcome at 6 months after nerve grafting was evaluated by a combination of electrophysiological assessment, FluoroGold retrograde tracing, and histological investigation to regenerated nerve tissue and reinnervated target muscle. The experimental results indicated that introduction of autologous MSCs to the chitosan/PLGA-based neural scaffold promoted sciatic nerve regeneration and functional recovery, demonstrating significant efficacy that was, to a certain degree, close to that by nerve autografting, a gold standard for treating large peripheral nerve gaps, and better than that by grafting with the chitosan/PLGA-based scaffold alone.

  9. Organellar calcium buffers.

    PubMed

    Prins, Daniel; Michalak, Marek

    2011-03-01

    Ca(2+) is an important intracellular messenger affecting many diverse processes. In eukaryotic cells, Ca(2+) storage is achieved within specific intracellular organelles, especially the endoplasmic/sarcoplasmic reticulum, in which Ca(2+) is buffered by specific proteins known as Ca(2+) buffers. Ca(2+) buffers are a diverse group of proteins, varying in their affinities and capacities for Ca(2+), but they typically also carry out other functions within the cell. The wide range of organelles containing Ca(2+) and the evidence supporting cross-talk between these organelles suggest the existence of a dynamic network of organellar Ca(2+) signaling, mediated by a variety of organellar Ca(2+) buffers.

  10. Rapid method for DNA extraction from the honey bee Apis mellifera and the parasitic bee mite Varroa destructor using lysis buffer and proteinase K.

    PubMed

    Issa, M R C; Figueiredo, V L C; De Jong, D; Sakamoto, C H; Simões, Z L P

    2013-10-22

    We developed a rapid method for extraction of DNA from honey bees, Apis mellifera, and from the parasitic bee mite, Varroa destructor. The advantages include fast processing and low toxicity of the substances that are utilized. We used lysis buffer with nonionic detergents to lyse cell walls and proteinase K to digest proteins. We tested whole thorax, thoracic muscle mass, legs, and antennae from individual bees; the mites were processed whole (1 mite/sample). Each thorax was incubated whole, without cutting, because exocuticle color pigment darkened the extraction solution, interfering with PCR results. The procedure was performed with autoclaved equipment and laboratory gloves. For each sample, we used 100 µL lysis buffer (2 mL stock solution of 0.5 M Tris/HCl, pH 8.5, 10 mL stock solution of 2 M KCl, 500 µL solution of 1 M MgCl2, 2 mL NP40, and 27.6 g sucrose, completed to 200 mL with bidistilled water and autoclaved) and 2 µL proteinase K (10 mg/mL in bidistilled water previously autoclaved, as proteinase K cannot be autoclaved). Tissues were incubated in the solutions for 1-2 h in a water bath (62°-68 °C) or overnight at 37 °C. After incubation, the tissues were removed from the extraction solution (lysis buffer + proteinase K) and the solution heated to 92 °C for 10 min, for proteinase K inactivation. Then, the solution with the extracted DNA was stored in a refrigerator (4°-8 °C) or a freezer (-20 °C). This method does not require centrifugation or phenol/chloroform extraction. The reduced number of steps allowed us to sample many individuals/day. Whole mites and bee antennae were the most rapidly processed. All bee tissues gave the same quality DNA. This method, even using a single bee antenna or a single mite, was adequate for extraction and analysis of bee genomic and mitochondrial DNA and mite genomic DNA.

  11. Common data buffer

    NASA Technical Reports Server (NTRS)

    Byrne, F.

    1981-01-01

    Time-shared interface speeds data processing in distributed computer network. Two-level high-speed scanning approach routes information to buffer, portion of which is reserved for series of "first-in, first-out" memory stacks. Buffer address structure and memory are protected from noise or failed components by error correcting code. System is applicable to any computer or processing language.

  12. Buffer Therapy for Cancer

    PubMed Central

    Ribeiro, Maria de Lourdes C; Silva, Ariosto S.; Bailey, Kate M.; Kumar, Nagi B.; Sellers, Thomas A.; Gatenby, Robert A.; Ibrahim-Hashim, Arig; Gillies, Robert J.

    2013-01-01

    Oral administration of pH buffers can reduce the development of spontaneous and experimental metastases in mice, and has been proposed in clinical trials. Effectiveness of buffer therapy is likely to be affected by diet, which could contribute or interfere with the therapeutic alkalinizing effect. Little data on food pH buffering capacity was available. This study evaluated the pH and buffering capacity of different foods to guide prospective trials and test the effect of the same buffer (lysine) at two different ionization states. Food groups were derived from the Harvard Food Frequency Questionnaire. Foods were blended and pH titrated with acid from initial pH values until 4.0 to determine “buffering score”, in mmol H+/pH unit. A “buffering score” was derived as the mEq H+ consumed per serving size to lower from initial to a pH 4.0, the postprandial pH of the distal duodenum. To differentiate buffering effect from any metabolic byproduct effects, we compared the effects of oral lysine buffers prepared at either pH 10.0 or 8.4, which contain 2 and 1 free base amines, respectively. The effect of these on experimental metastases formation in mice following tail vein injection of PC-3M prostate cancer cells were monitored with in vivo bioluminescence. Carbohydrates and dairy products’ buffering score varied between 0.5 and 19. Fruits and vegetables showed a low to zero buffering score. The score of meats varied between 6 and 22. Wine and juices had negative scores. Among supplements, sodium bicarbonate and Tums® had the highest buffering capacities, with scores of 11 and 20 per serving size, respectively. The “de-buffered” lysine had a less pronounced effect of prevention of metastases compared to lysine at pH 10. This study has demonstrated the anti-cancer effects of buffer therapy and suggests foods that can contribute to or compete with this approach to manage cancer. PMID:24371544

  13. Valuation of forested buffers

    NASA Astrophysics Data System (ADS)

    Basnyat, Prakash

    The research concentrated on two fronts: (1) defining relationships between land use complex and nitrate and sediment concentrations; and (2) developing a method for assessing the extent of potential and water quality improvements available through land management options and their associated costs. In this work, selected basins of the Fish River (Alabama) were delineated, land use/land cover types were classified, and "contributing zones" were delineated using Geographic Information System (GIS) and Remote Sensing (RS) analytical tools. Water samples collected from these basins were analyzed for their nutrient contents. Based on measured nitrate and sediment concentrations in basin streams, a linkage model was developed. This linkage model relates land use/land cover with the pollution levels in the stream. The linkage model was evaluated at three different scales: (1) the basin scale; (2) the contributing zone scale; and (3) the stream buffer/riparian zone scale. The contributing zone linkage model suggests that forests act as a sink or transformation zone. Residential/urban/built-up areas were identified as the strongest contributors of nitrate in the contributing zones model and active agriculture was identified as the second largest contributor. Regression results for the "land use/land cover diversity" model (stream buffer/riparian zone scale) suggest that areas that are close (adjacent) to the stream and any disturbances in these areas will have major impacts on stream water quality. The economic model suggests the value of retiring lands from agricultural land uses to forested buffers varies from 0 to 3067 per hectare, depending on the types of crops currently grown. Along with conversion costs, this land value forms the basis for estimates of the costs of land management options for improving (or maintaining) water quality throughout the study area. The model also shows the importance of stream-side management zones, which are key to maintenance of stream

  14. Buffer Capacity: An Undergraduate Laboratory Experiment.

    ERIC Educational Resources Information Center

    Russo, Steven O.; Hanania, George I. H.

    1987-01-01

    Describes a quantitative experiment designed to demonstrate buffer action and the measurement of buffer capacity. Discusses how to make acetate buffers, determine their buffer capacity, plot the capacity/pH curve, and interpret the data obtained. (TW)

  15. Virtual Frame Buffer Interface Program

    NASA Technical Reports Server (NTRS)

    Wolfe, Thomas L.

    1990-01-01

    Virtual Frame Buffer Interface program makes all frame buffers appear as generic frame buffer with specified set of characteristics, allowing programmers to write codes that run unmodified on all supported hardware. Converts generic commands to actual device commands. Consists of definition of capabilities and FORTRAN subroutines called by application programs. Developed in FORTRAN 77 for DEC VAX 11/780 or DEC VAX 11/750 computer under VMS 4.X.

  16. Buffer capacity of biologics--from buffer salts to buffering by antibodies.

    PubMed

    Karow, Anne R; Bahrenburg, Sven; Garidel, Patrick

    2013-01-01

    Controlling pH is essential for a variety of biopharmaceutical process steps. The chemical stability of biologics such as monoclonal antibodies is pH-dependent and slightly acidic conditions are favorable for stability in a number of cases. Since control of pH is widely provided by added buffer salts, the current study summarizes the buffer characteristics of acetate, citrate, histidine, succinate, and phosphate buffers. Experimentally derived values largely coincide with values calculated from a model that had been proposed in 1922 by van Slyke. As high concentrated protein formulations become more and more prevalent for biologics, the self-buffering potential of proteins becomes of relevance. The current study provides information on buffer characteristics for pH ranges down to 4.0 and up to 8.0 and shows that a monoclonal antibody at 50 mg/mL exhibits similar buffer capacity as 6 mM citrate or 14 mM histidine (pH 5.0-6.0). Buffer capacity of antibody solutions scales linearly with protein concentration up to more than 200 mg/mL. At a protein concentration of 220 mg/mL, the buffer capacity resembles the buffer capacity of 30 mM citrate or 50 mM histidine (pH 5.0-6.0). The buffer capacity of monoclonal antibodies is practically identical at the process relevant temperatures 5, 25, and 40°C. Changes in ionic strength of ΔI=0.15, in contrast, can alter the buffer capacity up to 35%. In conclusion, due to efficient self-buffering by antibodies in the pH range of favored chemical stability, conventional buffer excipients could be dispensable for pH stabilization of high concentrated protein solutions.

  17. Ring Buffered Network Bus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This report describes the research effort to demonstrate the integration of a data sharing technology, Ring Buffered Network Bus, in development by Dryden Flight Research Center, with an engine simulation application, the Java Gas Turbine Simulator, in development at the University of Toledo under a grant from the Glenn Research Center. The objective of this task was to examine the application of the RBNB technologies as a key component in the data sharing, health monitoring and system wide modeling elements of the NASA Aviation Safety Program (AVSP) [Golding, 1997]. System-wide monitoring and modeling of aircraft and air safety systems will require access to all data sources which are relative factors when monitoring or modeling the national airspace such as radar, weather, aircraft performance, engine performance, schedule and planning, airport configuration, flight operations, etc. The data sharing portion of the overall AVSP program is responsible for providing the hardware and software architecture to access and distribute data, including real-time flight operations data, among all of the AVSP elements. The integration of an engine code capable of numerically "flying" through recorded flight paths and weather data using a software tool that allows for distributed access of data to this engine code demonstrates initial steps toward building a system capable of monitoring and modeling the National Airspace.

  18. Oracle Log Buffer Queueing

    SciTech Connect

    Rivenes, A S

    2004-12-08

    The purpose of this document is to investigate Oracle database log buffer queuing and its affect on the ability to load data using a specialized data loading system. Experiments were carried out on a Linux system using an Oracle 9.2 database. Previous experiments on a Sun 4800 running Solaris had shown that 100,000 entities per minute was an achievable rate. The question was then asked, can we do this on Linux, and where are the bottlenecks? A secondary question was also lurking, how can the loading be further scaled to handle even higher throughput requirements? Testing was conducted using a Dell PowerEdge 6650 server with four CPUs and a Dell PowerVault 220s RAID array with 14 36GB drives and 128 MB of cache. Oracle Enterprise Edition 9.2.0.4 was used for the database and Red Hat Linux Advanced Server 2.1 was used for the operating system. This document will detail the maximum observed throughputs using the same test suite that was used for the Sun tests. A detailed description of the testing performed along with an analysis of bottlenecks encountered will be made. Issues related to Oracle and Linux will also be detailed and some recommendations based on the findings.

  19. Mechanisms of buffer therapy resistance.

    PubMed

    Bailey, Kate M; Wojtkowiak, Jonathan W; Cornnell, Heather H; Ribeiro, Maria C; Balagurunathan, Yoganand; Hashim, Arig Ibrahim; Gillies, Robert J

    2014-04-01

    Many studies have shown that the acidity of solid tumors contributes to local invasion and metastasis. Oral pH buffers can specifically neutralize the acidic pH of tumors and reduce the incidence of local invasion and metastatic formation in multiple murine models. However, this effect is not universal as we have previously observed that metastasis is not inhibited by buffers in some tumor models, regardless of buffer used. B16-F10 (murine melanoma), LL/2 (murine lung) and HCT116 (human colon) tumors are resistant to treatment with lysine buffer therapy, whereas metastasis is potently inhibited by lysine buffers in MDA-MB-231 (human breast) and PC3M (human prostate) tumors. In the current work, we confirmed that sensitive cells utilized a pH-dependent mechanism for successful metastasis supported by a highly glycolytic phenotype that acidifies the local tumor microenvironment resulting in morphological changes. In contrast, buffer-resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive secretion of matrix degrading proteases without elevated glycolysis. These results have identified two distinct mechanisms of experimental metastasis, one of which is pH-dependent (buffer therapy sensitive cells) and one which is pH-independent (buffer therapy resistant cells). Further characterization of these models has potential for therapeutic benefit.

  20. Midgut proteases of the cardamom shoot and capsule borer Conogethes punctiferalis (Lepidoptera: Pyralidae) and their interaction with aprotinin.

    PubMed

    Josephrajkumar, A; Chakrabarty, R; Thomas, G

    2006-02-01

    Protease inhibitors cause mortality in a range of insects, and transgenic plants expressing protease inhibitors have been protected against pest attack, particularly internal feeders that are not amenable to control by conventional means. A study of luminal proteases in Conogethes punctiferalis Guenée was performed to identify potential targets for proteinaceous biopesticides, such as protease inhibitors. The midgut protease profile of the gut lumen from C. punctiferalis was studied to determine the conditions for optimal protein hydrolysis. Optimum conditions for peptidase activity were found to be in 50 mm Tris-HCl, pH 10 containing 20 mm CaCl2; incubation for 30 min at 40 degrees C. Four synthetic substrates, i.e. benzoyl-arg-p-nitroanilide, benzoyl-tyr-p-nitroanilide, succinyl-ala-ala-pro-leu-p-nitroanilide (SAAPLpNA) and leu-p-nitroanilide were hydrolysed by C. punctiferalis gut proteases in Tris-HCl buffer pH 10. Trypsin and elastase-like chymotrypsin were the prominent digestive proteases, and age-related modulation of midgut proteases existed for trypsin, chymotrypsin, elastase-like chymotrypsin and leucine aminopeptidase. Serine protease inhibitors such as aprotinin, soybean trypsin inhibitor and phenylmethanesulfonyl fluoride inhibited peptidase activity. Some metal ions such as Ca(2+), Mg(2+), Pb(2+) and Co(2+) enhanced BApNA-ase activity whereas others like Mn(2+), Zn(2+), Cu(2+), Fe(2+) and Hg(2+) were inhibitory at 6 mm concentration. Trypsin and elastase-like chymotrypsin were significantly inhibited by 94% and 29%, respectively, by aprotinin (150 nm) under in vitro conditions. A possible incorporation of protease inhibitors into transgenic plants is discussed.

  1. Optimization of conditions for the single step IMAC purification of miraculin from Synsepalum dulcificum.

    PubMed

    He, Zuxing; Tan, Joo Shun; Lai, Oi Ming; Ariff, Arbakariya B

    2015-08-15

    In this study, the methods for extraction and purification of miraculin from Synsepalum dulcificum were investigated. For extraction, the effect of different extraction buffers (phosphate buffer saline, Tris-HCl and NaCl) on the extraction efficiency of total protein was evaluated. Immobilized metal ion affinity chromatography (IMAC) with nickel-NTA was used for the purification of the extracted protein, where the influence of binding buffer pH, crude extract pH and imidazole concentration in elution buffer upon the purification performance was explored. The total amount of protein extracted from miracle fruit was found to be 4 times higher using 0.5M NaCl as compared to Tris-HCl and phosphate buffer saline. On the other hand, the use of Tris-HCl as binding buffer gave higher purification performance than sodium phosphate and citrate-phosphate buffers in IMAC system. The optimum purification condition of miraculin using IMAC was achieved with crude extract at pH 7, Tris-HCl binding buffer at pH 7 and the use of 300 mM imidazole as elution buffer, which gave the overall yield of 80.3% and purity of 97.5%. IMAC with nickel-NTA was successfully used as a single step process for the purification of miraculin from crude extract of S. dulcificum.

  2. Extremophilic Enzymatic Response: Role of Proteins in Controlling Selenium Nanoparticle Synthesis

    DTIC Science & Technology

    2014-11-28

    pH 8.0 buffer containing 15 mM EDTA pH 8.0, lysozyme (1 mg/ml) and DNase I (10 µg/ml) and treated as described by Amenabar and Blamey, 2012. The...crude extract was loaded into a column (Pharmacia, C 16/20) of Q-Sepharose Fast Flow (Pharmacia Biotech), equilibrated with 50 mM Tris-HCl pH 8.0...applied to a column (Pharmacia, C 10/10) containing DEAE-Sepharose Fast Flow (Pharmacia Biotech) equilibrated with 50 mM Tris-HCl pH 8.0 buffer. The

  3. Hypoxia-Inducible Factor Prolyl Hydroxylases are Oxygen Sensors in the Brain

    DTIC Science & Technology

    2005-03-01

    prepared by lysing pelleted cells in RIPA buffer (0.1 % SDS, 1 % Nonidet P40 , 5 mM EDTA, 0.5 % sodium deoxycholate, 150 mM NaCl, 50 mM Tris/HCl, freshly...buffer (0.1% SDS, 1% Nonidet P40 , 5 mM EDTA, 0.5% sodium deoxycholate, 150 mM NaCl, 50 mM Tris/HCl, freshly supplemented with 2 mM dithiothreitol and

  4. Electrodialysis operation with buffer solution

    DOEpatents

    Hryn, John N.; Daniels, Edward J.; Krumdick, Greg K.

    2009-12-15

    A new method for improving the efficiency of electrodialysis (ED) cells and stacks, in particular those used in chemical synthesis. The process entails adding a buffer solution to the stack for subsequent depletion in the stack during electrolysis. The buffer solution is regenerated continuously after depletion. This buffer process serves to control the hydrogen ion or hydroxide ion concentration so as to protect the active sites of electrodialysis membranes. The process enables electrodialysis processing options for products that are sensitive to pH changes.

  5. Programmable pH buffers

    DOEpatents

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  6. Buffer Gas Acquisition and Storage

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.; Callahan, Richard A.; Delgado, H. (Technical Monitor)

    2001-01-01

    The acquisition and storage of buffer gases (primarily argon and nitrogen) from the Mars atmosphere provides a valuable resource for blanketing and pressurizing fuel tanks and as a buffer gas for breathing air for manned missions. During the acquisition of carbon dioxide (CO2), whether by sorption bed or cryo-freezer, the accompanying buffer gases build up in the carbon dioxide acquisition system, reduce the flow of CO2 to the bed, and lower system efficiency. It is this build up of buffer gases that provide a convenient source, which must be removed, for efficient capture Of CO2 Removal of this buffer gas barrier greatly improves the charging rate of the CO2 acquisition bed and, thereby, maintains the fuel production rates required for a successful mission. Consequently, the acquisition, purification, and storage of these buffer gases are important goals of ISRU plans. Purity of the buffer gases is a concern e.g., if the CO, freezer operates at 140 K, the composition of the inert gas would be approximately 21 percent CO2, 50 percent nitrogen, and 29 percent argon. Although there are several approaches that could be used, this effort focused on a hollow-fiber membrane (HFM) separation method. This study measured the permeation rates of CO2, nitrogen (ND, and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193K and 10 kpa to 300 kPa. Concentrations were measured with a gas chromatograph that used a thermoconductivity (TCD) detector with helium (He) as the carrier gas. The general trend as the temperature was lowered was for the membranes to become more selective, In addition, the relative permeation rates between the three gases changed with temperature. The end result was to provide design parameters that could be used to separate CO2 from N2 and Ar.

  7. Buffer gas acquisition and storage

    NASA Astrophysics Data System (ADS)

    Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.

    2001-02-01

    The acquisition and storage of buffer gases (primarily argon and nitrogen) from the Mars atmosphere provides a valuable resource for blanketing and pressurizing fuel tanks and as a buffer gas for breathing air for manned missions. During the acquisition of carbon dioxide (CO2), whether by sorption bed or cryo-freezer, the accompanying buffer gases build up in the carbon dioxide acquisition system, reduce the flow of CO2 to the bed, and lower system efficiency. It is this build up of buffer gases that provide a convenient source, which must be removed, for efficient capture of CO2. Removal of this buffer gas barrier greatly improves the charging rate of the CO2 acquisition bed and, thereby, maintains the fuel production rates required for a successful mission. Consequently, the acquisition, purification, and storage of these buffer gases are important goals of ISRU plans. Purity of the buffer gases is a concern e.g., if the CO2 freezer operates at 140 K, the composition of the inert gas would be approximately 21 percent CO2, 50 percent nitrogen, and 29 percent argon. Although there are several approaches that could be used, this effort focused on a hollow-fiber membrane (HFM) separation method. This study measured the permeation rates of CO2, nitrogen (N2), and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193 K and 10 kPa to 300 kPa. Concentrations were measured with a gas chromatograph. The end result was data necessary to design a system that could separate CO2, N2, and Ar. .

  8. Free flow cell electrophoresis using zwitterionic buffer

    NASA Technical Reports Server (NTRS)

    Rodkey, R. Scott

    1990-01-01

    Studies of a zwitterionic buffer formulated for cell electrophoresis were done using the McDonnell-Douglas Continuous Flow Electrophoresis System. Standard buffers were analyzed for their stability in the electrical field and the results showed that both buffers tested were inherently unstable. Further, titration studies showed that the standards buffers buffered poorly at the pH employed for electrophoresis. The zwitterionic buffer buffered well at its nominal pH and was shown to be stable in the electrical field. Comparative studies of the buffer with standard cell separation buffers using formalin fixed rabbit and goose red blood cells showed that the zwitterionic buffer gave better resolution of the fixed cells. Studies with viable hybridoma cells showed that buffer Q supported cell viability equal to Hank's Balanced Salt Solution and that hybridoma cells in different stages of the growth cycle demonstrated reproducible differences in electrophoretic mobility.

  9. The Mechanism of Action of Unique Small Molecules that Inhibit the Pim Protein Kinase Blocking Prostate Cancer Cell Growth

    DTIC Science & Technology

    2010-05-01

    NaCl, 10 mM Tris-HCl, pH 7.5, 1% Nonidet P - 40 , 0.5% deoxycholate, 0.1%SDS), thenwashed twice in 1 kinase buffer (25 mM Tris-HCl, pH 7.5, 5 mM...ubiquitination assays were per- formed as described ( 40 ). HEK293T cells were transfected with the indicated plasmids for 24 h, treated with 10 M MG132...Student’s t test. p Pim-1 Regulates Skp2 Levels SEPTEMBER 17, 2010 • VOLUME 285 • NUMBER 38 JOURNAL OF BIOLOGICAL CHEMISTRY 29129 at M U S C Library, on M

  10. Buffering in cyclic gene networks

    NASA Astrophysics Data System (ADS)

    Glyzin, S. D.; Kolesov, A. Yu.; Rozov, N. Kh.

    2016-06-01

    We consider cyclic chains of unidirectionally coupled delay differential-difference equations that are mathematical models of artificial oscillating gene networks. We establish that the buffering phenomenon is realized in these system for an appropriate choice of the parameters: any given finite number of stable periodic motions of a special type, the so-called traveling waves, coexist.

  11. An integrated recirculating optical buffer.

    PubMed

    Park, Hyundai; Mack, John P; Bluementhal, Daniel J; Bowers, John E

    2008-07-21

    This paper reports an integrated optical buffer consisting of a low loss silicon waveguide delay line and a silicon evanescent gate matrix switch. The integrated device demonstrates an error free operation at 40 Gb/s data rate with a packet delay of 1.1 ns. This demonstration also highlights the silicon evanescent device platform to realize new types of photonic integrated devices by combining the low loss silicon passive components with the silicon evanescent photonic active devices.

  12. Laser velocimeter (autocovariance) buffer interface

    NASA Technical Reports Server (NTRS)

    Clemmons, J. I., Jr.

    1981-01-01

    A laser velocimeter (autocovariance) buffer interface (LVABI) was developed to serve as the interface between three laser velocimeter high speed burst counters and a minicomputer. A functional description is presented of the instrument and its unique features which allow the studies of flow velocity vector analysis, turbulence power spectra, and conditional sampling of other phenomena. Typical applications of the laser velocimeter using the LVABI are presented to illustrate its various capabilities.

  13. Cell buffer with built-in test

    NASA Technical Reports Server (NTRS)

    Ott, William E. (Inventor)

    2004-01-01

    A cell buffer with built-in testing mechanism is provided. The cell buffer provides the ability to measure voltage provided by a power cell. The testing mechanism provides the ability to test whether the cell buffer is functioning properly and thus providing an accurate voltage measurement. The testing mechanism includes a test signal-provider to provide a test signal to the cell buffer. During normal operation, the test signal is disabled and the cell buffer operates normally. During testing, the test signal is enabled and changes the output of the cell buffer in a defined way. The change in the cell buffer output can then be monitored to determine if the cell buffer is functioning correctly. Specifically, if the voltage output of the cell buffer changes in a way that corresponds to the provided test signal, then the functioning of the cell buffer is confirmed. If the voltage output of the cell buffer does not change correctly, then the cell buffer is known not to be operating correctly. Thus, the built in testing mechanism provides the ability to quickly and accurately determine if the cell buffer is operating correctly. Furthermore, the testing mechanism provides this functionality without requiring excessive device size and complexity.

  14. Role of Buffers in Protein Formulations.

    PubMed

    Zbacnik, Teddy J; Holcomb, Ryan E; Katayama, Derrick S; Murphy, Brian M; Payne, Robert W; Coccaro, Richard C; Evans, Gabriel J; Matsuura, James E; Henry, Charles S; Manning, Mark Cornell

    2017-03-01

    Buffers comprise an integral component of protein formulations. Not only do they function to regulate shifts in pH, they also can stabilize proteins by a variety of mechanisms. The ability of buffers to stabilize therapeutic proteins whether in liquid formulations, frozen solutions, or the solid state is highlighted in this review. Addition of buffers can result in increased conformational stability of proteins, whether by ligand binding or by an excluded solute mechanism. In addition, they can alter the colloidal stability of proteins and modulate interfacial damage. Buffers can also lead to destabilization of proteins, and the stability of buffers themselves is presented. Furthermore, the potential safety and toxicity issues of buffers are discussed, with a special emphasis on the influence of buffers on the perceived pain upon injection. Finally, the interaction of buffers with other excipients is examined.

  15. Buffer Zone Requirements for Soil Fumigant Applications

    EPA Pesticide Factsheets

    Updated pesticide product labels require fumigant users to establish a buffer zone around treated fields to reduce risks to bystanders. Useful information includes tarp testing guidance and a buffer zone calculator.

  16. Urban Runoff: Model Ordinances for Aquatic Buffers

    EPA Pesticide Factsheets

    Aquatic Buffers serve as natural boundaries between local waterways and existing development. The model and example ordinaces below provide suggested language or technical guidance designed to create the most effective stream buffer zones possible.

  17. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes voyage, steering gear other than hydraulic must be designed with suitable buffering arrangements to relieve...

  18. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes voyage, steering gear other than hydraulic must be designed with suitable buffering arrangements to relieve...

  19. Doped LZO buffer layers for laminated conductors

    DOEpatents

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2010-03-23

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  20. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    EPA Science Inventory

    Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

  1. Improving Water Quality With Conservation Buffers

    NASA Astrophysics Data System (ADS)

    Lowrance, R.; Dabney, S.; Schultz, R.

    2003-12-01

    Conservation buffer technologies are new approaches that need wider application. In-field buffer practices work best when used in combination with other buffer types and other conservation practices. Vegetative barriers may be used in combination with edge-of-field buffers to protect and improve their function and longevity by dispersing runoff and encouraging sediment deposition upslope of the buffer. It's important to understand how buffers can be managed to help reduce nutrient transport potential for high loading of nutrients from manure land application sites, A restored riparian wetland buffer retained or removed at least 59 percent of the nitrogen and 66 percent of the phosphorus that entered from an adjacent manure land application site. The Bear Creek National Restoration Demonstration Watershed project in Iowa has been the site of riparian forest buffers and filter strips creation; constructed wetlands to capture tile flow; stream-bank bioengineering; in-stream structures; and controlling livestock grazing. We need field studies that test various widths of buffers of different plant community compositions for their efficacy in trapping surface runoff, reducing nonpoint source pollutants in subsurface waters, and enhancing the aquatic ecosystem. Research is needed to evaluate the impact of different riparian grazing strategies on channel morphology, water quality, and the fate of livestock-associated pathogens and antibiotics. Integrating riparian buffers and other conservation buffers into these models is a key objective in future model development.

  2. Buffered Electrochemical Polishing of Niobium

    SciTech Connect

    Gianluigi Ciovati; Tian, Hui; Corcoran, Sean

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  3. Melatonin: Buffering the Immune System

    PubMed Central

    Carrillo-Vico, Antonio; Lardone, Patricia J.; Álvarez-Sánchez, Nuria; Rodríguez-Rodríguez, Ana; Guerrero, Juan M.

    2013-01-01

    Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed. PMID:23609496

  4. Selective frame dropping based on hypothetical reference decoder buffer model for initial buffering delay reduction

    NASA Astrophysics Data System (ADS)

    Deshpande, Sachin

    2008-02-01

    We propose a method for selective frame dropping based on hypothetical reference decoder buffer model for initial buffering delay reduction. The client side buffering consists of two logical buffers: a de-jitter buffer and a pre-decoder buffer. To playback an encoded bit-stream without underflow the client must do a minimum initial buffering. This minimum initial buffering is a property of the bit-stream. The minimum initial buffering relates to the pre-decoder buffer. In addition the client can do additional initial buffering to handle network jitter and other bandwidth variations. Our proposed approach relates to reducing the minimum initial buffering delay for an already encoded bit-stream. We propose a method for selectively dropping frames to reduce the amount of initial buffering the client needs to do to avoid underflow during the streaming. Our proposed method is especially applicable to pre-stored content. The method is also particularly useful for variable bit-rate (VBR) encoded media. The method can be used by a streaming server. Alternatively the method can be implemented by a trans-rater/ transcoder. In a preferred embodiment our method can be applied in advance on a pre-stored bit-stream to decide which frames to drop to reduce the required minimum initial buffering.

  5. Buffer strips in composites at elevated temperature

    NASA Technical Reports Server (NTRS)

    Bigelow, C. A.

    1983-01-01

    The composite material 'buffer strip' concept is presently investigated at elevated temperatures for the case of graphite/polyimide buffer strip panels using a (45/0/45/90)2S layup, where the buffer strip material was 0-deg S-glass/polyimide. Each panel was loaded in tension until it failed, and radiographs and crack opening displacements were recorded during the tests to determine fracture onset, fracture arrest, and the extent of damage in the buffer strip after crack arrest. At 177 + or - 3 C, the buffer strips increased the panel strength by at least 40 percent in comparison with panels without buffer strips. Compared to similar panels tested at room temperature, those tested at elevated temperature had lower residual strengths, but higher failure strains.

  6. Signature-based store checking buffer

    DOEpatents

    Sridharan, Vilas; Gurumurthi, Sudhanva

    2015-06-02

    A system and method for optimizing redundant output verification, are provided. A hardware-based store fingerprint buffer receives multiple instances of output from multiple instances of computation. The store fingerprint buffer generates a signature from the content included in the multiple instances of output. When a barrier is reached, the store fingerprint buffer uses the signature to verify the content is error-free.

  7. SODR Memory Control Buffer Control ASIC

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1994-01-01

    The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

  8. High stability buffered phase comparator

    NASA Technical Reports Server (NTRS)

    Adams, W. A.; Reinhardt, V. S. (Inventor)

    1984-01-01

    A low noise RF signal phase comparator comprised of two high stability driver buffer amplifiers driving a double balanced mixer which operate to generate a beat frequency between the two RF input signals coupled to the amplifiers from the RF sources is described. The beat frequency output from the mixer is applied to a low noise zero crossing detector which is the phase difference between the two RF inputs. Temperature stability is provided by mounting the amplifiers and mixer on a common circuit board with the active circuit elements located on one side of a circuit board and the passive circuit elements located on the opposite side. A common heat sink is located adjacent the circuit board. The active circuit elements are embedded into the bores of the heat sink which slows the effect of ambient temperature changes and reduces the temperature gradients between the active circuit elements, thus improving the cancellation of temperature effects. The two amplifiers include individual voltage regulators, which increases RF isolation.

  9. Buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions: from protein buffer capacity prediction to bioprocess applications.

    PubMed

    Bahrenburg, Sven; Karow, Anne R; Garidel, Patrick

    2015-04-01

    Protein therapeutics, including monoclonal antibodies (mAbs), have significant buffering capacity, particularly at concentrations>50 mg/mL. This report addresses pH-related issues critical to adoption of self-buffered monoclonal antibody formulations. We evaluated solution conditions with protein concentrations ranging from 50 to 250 mg/mL. Samples were both buffer-free and conventionally buffered with citrate. Samples were non-isotonic or adjusted for isotonicity with NaCl or trehalose. Studies included accelerated temperature stability tests, shaking stability studies, and pH changes in infusion media as protein concentrate is added. We present averaged buffering slopes of capacity that can be applied to any mAb and present a general method for calculating buffering capacity of buffer-free, highly concentrated antibody liquid formulations. In temperature stability tests, neither buffer-free nor conventionally buffered solution conditions showed significant pH changes. Conventionally buffered solutions showed significantly higher opalescence than buffer-free ones. In general, buffer-free solution conditions showed less aggregation than conventionally buffered solutions. Shaking stability tests showed no differences between buffer-free and conventionally buffered solutions. "In-use" preparation experiments showed that pH in infusion bag medium can rapidly approximate that of self-buffered protein concentrate as concentrate is added. In summary, the buffer capacity of proteins can be predicted and buffer-free therapeutic antibody preparations provide a viable alternative to conventionally buffered solutions.

  10. Buffer Management Simulation in ATM Networks

    NASA Technical Reports Server (NTRS)

    Yaprak, E.; Xiao, Y.; Chronopoulos, A.; Chow, E.; Anneberg, L.

    1998-01-01

    This paper presents a simulation of a new dynamic buffer allocation management scheme in ATM networks. To achieve this objective, an algorithm that detects congestion and updates the dynamic buffer allocation scheme was developed for the OPNET simulation package via the creation of a new ATM module.

  11. FIFO Buffer for Asynchronous Data Streams

    NASA Technical Reports Server (NTRS)

    Bascle, K. P.

    1985-01-01

    Variable-rate, asynchronous data signals from up to four measuring instruments or other sources combined in first-in/first-out (FIFO) buffer for transmission on single channel. Constructed in complementary metal-oxide-semiconductor (CMOS) logic, buffer consumes low power (only 125 mW at 5V) and conforms to aerospace standards of reliability and maintainability.

  12. Riparian buffer transpiration and watershed scale impacts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forested riparian buffers are prevalent throughout the Southeastern Coastal Plain Region of the United States (US). Because they make up a significant portion of the regional landscape, transpiration within these riparian buffers is believed to have an important impact on the hydrologic budget of r...

  13. African American College Women's Suicide Buffers.

    ERIC Educational Resources Information Center

    Marion, Michelle S.; Range, Lillian M.

    2003-01-01

    To examine the relationships buffers may have with suicide ideation, 300 African American female college students completed measures of suicide ideation and buffers. Three variables accounted for a significant and unique portion of the variance in suicide ideation: family support, a view that suicide is unacceptable, and a collaborative religious…

  14. UNDERSTANDING, DERIVING, AND COMPUTING BUFFER CAPACITY

    EPA Science Inventory

    Derivation and systematic calculation of buffer capacity is a topic that seems often to be neglected in chemistry courses and given minimal treatment in most texts. However, buffer capacity is very important in the chemistry of natural waters and potable water. It affects corro...

  15. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  16. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  17. 46 CFR 58.25-45 - Buffers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Buffers. 58.25-45 Section 58.25-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-45 Buffers. For each vessel on an ocean, coastwise, or Great Lakes...

  18. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine...

  19. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine...

  20. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine...

  1. Optimization of protein buffer cocktails using Thermofluor.

    PubMed

    Reinhard, Linda; Mayerhofer, Hubert; Geerlof, Arie; Mueller-Dieckmann, Jochen; Weiss, Manfred S

    2013-02-01

    The stability and homogeneity of a protein sample is strongly influenced by the composition of the buffer that the protein is in. A quick and easy approach to identify a buffer composition which increases the stability and possibly the conformational homogeneity of a protein sample is the fluorescence-based thermal-shift assay (Thermofluor). Here, a novel 96-condition screen for Thermofluor experiments is presented which consists of buffer and additive parts. The buffer screen comprises 23 different buffers and the additive screen includes small-molecule additives such as salts and nucleotide analogues. The utilization of small-molecule components which increase the thermal stability of a protein sample frequently results in a protein preparation of higher quality and quantity and ultimately also increases the chances of the protein crystallizing.

  2. [Mechanical buffering characteristics of feline paw pads].

    PubMed

    Zhang, Xiaopeng; Yang, Jialing; Yu, Hui

    2012-12-01

    In the long time of natural evolution, the bodies of some animals, such as feline, that live in the wild and complicate surroundings have evolved to possess outstanding buffering characteristics, which make the animals adapt to the environment perfectly. These animals generally have well-developed paw pads under their soles to play an important role in attenuating the intensity of impact when they land on the ground. Investigating the buffering characteristics of these animals' paw pads could help us to design "bionic" buffering and energy-absorption devices. In this paper, based on observations of animal jumping test, a simple mass-spring-buffer model was proposed to explore the buffering characteristics of the animals' paw pads. By analytically solving the differential equations of this model, the parameters concerned with paw pads functions were discussed and some significant results were obtained.

  3. Are buffers boring? Uniqueness and asymptotical stability of traveling wave fronts in the buffered bistable system.

    PubMed

    Tsai, Je-Chiang; Sneyd, James

    2007-04-01

    Traveling waves of calcium are widely observed under the condition that the free cytosolic calcium is buffered. Thus it is of physiological interest to determine how buffers affect the properties of calcium waves. Here we summarise and extend previous results on the existence, uniqueness and stability of traveling wave solutions of the buffered bistable equation, which is the simplest possible model of the upstroke of a calcium wave. Taken together, the results show that immobile buffers do not change the existence, uniqueness or stability of the traveling wave, while mobile buffers can eliminate a traveling wave. However, if a wave exists in the latter case, it remains unique and stable.

  4. Electrophoretic mobilities of erythrocytes in various buffers

    NASA Technical Reports Server (NTRS)

    Plank, L. D.; Kunze, M. E.; Todd, P. W.

    1985-01-01

    The calibration of space flight equipment depends on a source of standard test particles, this test particle of choice is the fixed erythrocyte. Erythrocytes from different species have different electrophoretic mobilities. Electrophoretic mobility depends upon zeta potential, which, in turn depends upon ionic strength. Zeta potential decreases with increasing ionic strength, so cells have high electrophoretic mobility in space electrophoresis buffers than in typical physiological buffers. The electrophoretic mobilities of fixed human, rat, and rabbit erythrocytes in 0.145 M salt and buffers of varying ionic strength, temperature, and composition, to assess the effects of some of the unique combinations used in space buffers were characterized. Several effects were assessed: glycerol or DMSO (dimethylsulfoxide) were considered for use as cryoprotectants. The effect of these substances on erythrocyte electrophoretic mobility was examined. The choice of buffer depended upon cell mobility. Primary experiments with kidney cells established the choice of buffer and cryoprotectant. A nonstandard temperature of EPM in the suitable buffer was determined. A loss of ionic strength control occurs in the course of preparing columns for flight, the effects of small increases in ionic strength over the expected low values need to be evaluated.

  5. Social buffering: relief from stress and anxiety.

    PubMed

    Kikusui, Takefumi; Winslow, James T; Mori, Yuji

    2006-12-29

    Communication is essential to members of a society not only for the expression of personal information, but also for the protection from environmental threats. Highly social mammals have a distinct characteristic: when conspecific animals are together, they show a better recovery from experiences of distress. This phenomenon, termed 'social buffering', has been found in rodents, birds, non-human primates and also in humans. This paper reviews classical findings on social buffering and focuses, in particular, on social buffering effects in relation to neuroendocrine stress responses. The social cues that transmit social buffering signals, the neural mechanisms of social buffering and a partner's efficacy with respect to social buffering are also detailed. Social contact appears to have a very positive influence on the psychological and the physiological aspects of social animals, including human beings. Research leading towards further understanding of the mechanisms of social buffering could provide alternative medical treatments based on the natural, individual characteristics of social animals, which could improve the quality of life.

  6. A novel structure of optical buffer

    NASA Astrophysics Data System (ADS)

    Liu, AiMing; Wu, Chongqing; Gao, Huali; Gong, Yandong; Shum, Ping

    2005-02-01

    Optical buffers are critical for low packet-loss probability in future photonic packet-switched networks. In particular, they would be required to store packets during rate conversion and header processing, and to overcome the receiver's bottleneck. They would be required for queuing packets while transmitters await access to the network. In this paper, we present a novel structure of optical buffer with compact size. This kind of optical buffer is based on a collinear 3x3 fiber coupler in which three fibers are completely in the same plane and weakly coupled. A SOA is used as its nonlinear element as well as an amplifier in it.The experiment result will be also given in the paper. Storage results obtained with this novel structure optical buffer at 100Mb/s will be presented first and then its capacity is extended to higher data rates of 2.5Gb/s, more compatible with present optical networks. Storage has been observed for time up to 1.568ms(more than 32 circulations) in both cases without obvious degration. The novel structure of optical buffer could be a more compact device which makes it possible to be integrated in a chip. SOA in the buffer is used as a nonlinear element as well as an amplifier to compensate loss in the buffer loop. The buffer needs low control power for switch operation. It is easy to control 'write' and 'erase' operation because the same TOAD switch in the buffer can be used for both 'write' and 'erase' operation.

  7. Calculating Buffer Zones: A Guide for Applicators

    EPA Pesticide Factsheets

    Buffer zones provide distance between the application block (i.e., edge of the treated field) and bystanders, in order to control pesticide exposure risk from soil fumigants. Distance requirements may be reduced by credits such as tarps.

  8. Capture effeciency of a vegetative environmental buffer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Particulate matter emitted from tunnel-ventilated animal feeding operations (AFOs) is known to transport malodorous compounds. As a mitigation strategy, vegetative environmental buffers (VEBs) are often installed surrounding AFOs to capture particulates and induce lofting and dispersion. Currently, ...

  9. Buffer layer for thin film structures

    SciTech Connect

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  10. Buffer layer for thin film structures

    DOEpatents

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  11. Social buffering: relief from stress and anxiety

    PubMed Central

    Kikusui, Takefumi; Winslow, James T; Mori, Yuji

    2006-01-01

    Communication is essential to members of a society not only for the expression of personal information, but also for the protection from environmental threats. Highly social mammals have a distinct characteristic: when conspecific animals are together, they show a better recovery from experiences of distress. This phenomenon, termed ‘social buffering’, has been found in rodents, birds, non-human primates and also in humans. This paper reviews classical findings on social buffering and focuses, in particular, on social buffering effects in relation to neuroendocrine stress responses. The social cues that transmit social buffering signals, the neural mechanisms of social buffering and a partner's efficacy with respect to social buffering are also detailed. Social contact appears to have a very positive influence on the psychological and the physiological aspects of social animals, including human beings. Research leading towards further understanding of the mechanisms of social buffering could provide alternative medical treatments based on the natural, individual characteristics of social animals, which could improve the quality of life. PMID:17118934

  12. Buffer regulation of calcium puff sequences.

    PubMed

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-02-01

    Puffs are localized Ca(2 +) signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the result of the liberation of Ca(2 +) from the endoplasmic reticulum through the coordinated opening of IP3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca(2 +) provides a mechanism that enriches the spatio-temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca(2 +) signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP3R-Ca(2 +) channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca(2 +) buffer can increase the average number of channels that participate of a puff.

  13. Low noise buffer amplifiers and buffered phase comparators for precise time and frequency measurement and distribution

    NASA Technical Reports Server (NTRS)

    Eichinger, R. A.; Dachel, P.; Miller, W. H.; Ingold, J. S.

    1982-01-01

    Extremely low noise, high performance, wideband buffer amplifiers and buffered phase comparators were developed. These buffer amplifiers are designed to distribute reference frequencies from 30 KHz to 45 MHz from a hydrogen maser without degrading the hydrogen maser's performance. The buffered phase comparators are designed to intercompare the phase of state of the art hydrogen masers without adding any significant measurement system noise. These devices have a 27 femtosecond phase stability floor and are stable to better than one picosecond for long periods of time. Their temperature coefficient is less than one picosecond per degree C, and they have shown virtually no voltage coefficients.

  14. Temperature buffer test design, instrumentation and measurements

    NASA Astrophysics Data System (ADS)

    Sandén, Torbjörn; Goudarzi, Reza; de Combarieu, Michel; Åkesson, Mattias; Hökmark, Harald

    The Temperature Buffer Test, TBT, is a heated full-scale field experiment carried out jointly by ANDRA and SKB at the SKB Äspö Hard Rock Laboratory in Southeast Sweden. An existing 8 m deep, 1.8 m diameter KBS-3-type deposition hole located at -420 m level has been selected for the test. The objectives are to improve the general understanding of Thermo-Hydro-Mechanical, THM, behavior of buffer materials submitted to severe thermal conditions with temperatures well over 100 °C during water uptake of partly saturated bentonite-based buffer materials, and to check, in due time, their properties after water saturation. The test includes two carbon steel heating canisters each 3 m high and 0.6 m diameter, surrounded by 0.6 m of buffer material. There is a 0.2 m thick sand shield between the upper heater and the surrounding bentonite, while the lower heater is surrounded by bentonite only. On top of the stack of bentonite blocks is a confining plug anchored to the rock. In the slot between buffer and rock wall is a sand filter equipped with pipes to control the water pressure at the boundary, which is seldom done with an EBS in situ experiment. Both heater mid-height planes are densely instrumented in order to follow, with direct or indirect methods, buffer THM evolution. Temperature, relative humidity, stress and pore pressure have been monitored since the test start in March 2003. Total water inflow is also monitored. Firstly, the present paper describes the test design, the instrumentation, the plug anchoring system and the system for water boundary pressure control. Second, having described the test, the paper shows different measurements that illustrate evolution of temperature, saturation, suction and swelling pressure in the upper and the lower buffer.

  15. Undergraduate Chemistry Students' Perceptions of and Misconceptions about Buffers and Buffer Problems

    ERIC Educational Resources Information Center

    Orgill, MaryKay; Sutherland, Aynsley

    2008-01-01

    Both upper- and lower-level chemistry students struggle with understanding the concept of buffers and with solving corresponding buffer problems. While it might be reasonable to expect general chemistry students to struggle with this abstract concept, it is surprising that upper-level students in analytical chemistry and biochemistry continue to…

  16. Vegetative buffer strips for reducing herbicide transport in runoff: effects of season, vegetation, and buffer width

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effectiveness of vegetative buffer strips (VBS) for reducing herbicide transport in runoff may be affected by season, plant species composition, and buffer width. A plot-scale study was conducted from 2007-2012 on an eroded claypan soil with the objectives of: 1) assessing the effects of season ...

  17. Labview virtual instruments for calcium buffer calculations.

    PubMed

    Reitz, Frederick B; Pollack, Gerald H

    2003-01-01

    Labview VIs based upon the calculator programs of Fabiato and Fabiato (J. Physiol. Paris 75 (1979) 463) are presented. The VIs comprise the necessary computations for the accurate preparation of multiple-metal buffers, for the back-calculation of buffer composition given known free metal concentrations and stability constants used, for the determination of free concentrations from a given buffer composition, and for the determination of apparent stability constants from absolute constants. As implemented, the VIs can concurrently account for up to three divalent metals, two monovalent metals and four ligands thereof, and the modular design of the VIs facilitates further extension of their capacity. As Labview VIs are inherently graphical, these VIs may serve as useful templates for those wishing to adapt this software to other platforms.

  18. Nonlinear spelling in graphemic buffer deficit.

    PubMed

    Schubert, Teresa; Nickels, Lyndsey

    2015-01-01

    In this paper, we describe a case of nonlinear spelling and its implications for theories of the graphemic buffer. C.T.J., an individual with an acquired deficit of the graphemic buffer, often wrote the letters of his responses in a nonlinear temporal order when writing to dictation. The spatial ordering of the letters was maintained: Letters in the later positions of the words were written towards the right side of the response, even when written before letters in earlier positions. This unusual phenomenon has been briefly reported in three prior cases but this study provides the most detailed analysis of the phenomenon to date. We specifically contend that the decoupling of the temporal and spatial aspects of spelling is difficult to reconcile with competitive queuing accounts of the graphemic buffer.

  19. Buffers more than buffering agent: introducing a new class of stabilizers for the protein BSA.

    PubMed

    Gupta, Bhupender S; Taha, Mohamed; Lee, Ming-Jer

    2015-01-14

    In this study, we have analyzed the influence of four biological buffers on the thermal stability of bovine serum albumin (BSA) using dynamic light scattering (DLS). The investigated buffers include 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), 4-(2-hydroxyethyl)-1-piperazine-propanesulfonic acid (EPPS), 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid sodium salt (HEPES-Na), and 4-morpholinepropanesulfonic acid sodium salt (MOPS-Na). These buffers behave as a potential stabilizer for the native structure of BSA against thermal denaturation. The stabilization tendency follows the order of MOPS-Na > HEPES-Na > HEPES ≫ EPPS. To obtain an insight into the role of hydration layers and peptide backbone in the stabilization of BSA by these buffers, we have also explored the phase transition of a thermoresponsive polymer, poly(N-isopropylacrylamide (PNIPAM)), a model compound for protein, in aqueous solutions of HEPES, EPPS, HEPES-Na, and MOPS-Na buffers at different concentrations. It was found that the lower critical solution temperatures (LCST) of PNIPAM in the aqueous buffer solutions substantially decrease with increase in buffer concentration. The mechanism of interactions between these buffers and protein BSA was probed by various techniques, including UV-visible, fluorescence, and FTIR. The results of this series of studies reveal that the interactions are mainly governed by the influence of the buffers on the hydration layers surrounding the protein. We have also explored the possible binding sites of BSA with these buffers using a molecular docking technique. Moreover, the activities of an industrially important enzyme α-chymotrypsin (α-CT) in 0.05 M, 0.5 M, and 1.0 M of HEPES, EPPS, HEPES-Na, and MOPS-Na buffer solutions were analyzed at pH = 8.0 and T = 25 °C. Interestingly, the activities of α-CT were found to be enhanced in the aqueous solutions of these investigated buffers. Based upon the Jones-Dole viscosity parameters, the

  20. Buffer layers on biaxially textured metal substrates

    DOEpatents

    Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

    2001-01-01

    A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

  1. Body Buffer Zone and Proxemics in Blocking.

    ERIC Educational Resources Information Center

    Stockwell, John C.; Bahs, Clarence W.

    This paper investigates the effect of personal body buffer zones on compositional arrangements staged by novice directors. Relationships between directors' concepts of personal space and their projection of its dimensions into staging are studied through the use of a variety of proximity measures--distance, area angles of approach, and physical…

  2. Printing without Waiting: Buffers and Spoolers.

    ERIC Educational Resources Information Center

    Phillips, Brian

    1989-01-01

    Describes two methods to increase the speed of printing on microcomputers: (1) buffers, which are external storage devices used to temporarily store data bound for the printer; and (2) spoolers, which are software programs used to capture printer output and send it to the computer's memory or to a disk file. (LRW)

  3. The buffer effect in neutral electrolyte supercapacitors

    NASA Astrophysics Data System (ADS)

    Vindt, Steffen T.; Skou, Eivind M.

    2016-02-01

    The observation that double-layer capacitors based on neutral aqueous electrolytes can have significantly wider usable potential windows than those based on acidic or alkaline electrolytes is studied. This effect is explained by a local pH change taking place at the electrode surfaces, leading to a change in the redox potential of water in opposite directions on the two electrodes, resulting in the wider stability window. The magnitude of this effect is suggested to be dependent on the buffer capacity, rather than the intrinsic pH value of the electrolyte. This is confirmed by studying the impact of addition of a buffer to such systems. It is shown that a 56 % higher dynamic storage capacity may be achieved, simply by controlling the buffer capacity of the electrolyte. The model system used, is based on a well-known commercial activated carbon (NORIT™ A SUPRA) as the electrode material, aqueous potassium nitrate as the electrolyte and potassium phosphates as the buffer system.

  4. Buffer placement improves when topography is considered

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Best Management Practices (BMPs) protect streams by excluding cattle from streambanks and by filtering the run-off flowing from animal heavy use areas like feeding and watering stations. Conservation standards recommend placing buffers and filter strips downslope from heavy use areas, but do not exp...

  5. A Discovery Chemistry Experiment on Buffers

    ERIC Educational Resources Information Center

    Kulevich, Suzanne E.; Herrick, Richard S.; Mills, Kenneth V.

    2014-01-01

    The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory…

  6. Buffering children from marital conflict and dissolution.

    PubMed

    Katz, L F; Gottman, J M

    1997-06-01

    Examined several protective mechanisms that may reduce deleterious correlates of marital conflict and marital dissolution in young children. One set of potential buffers focused on parent-child interaction: parental warmth, parental scaffolding/praise, and inhibition of parental rejection. As a second set of potential buffers, each parent was interviewed about their "meta-emotion philosophy"--that is, their feelings about their own emotions, and their attitudes and responses to their children's anger and sadness. The third set of potential buffers concerned intraindividual characteristics of the child, including the child's intelligence and regulatory physiology (basal vagal tone and vagal suppression). Fifty-six families with a preschool child were studied at two time points: when the children were 5 years old (Time 1) and again when the children were 8 years old (Time 2). At Time 1, naturalistic observations of marital and parent-child interaction were conducted and assessment of child regulatory physiology was obtained through measures of basal vagal tone and suppression of vagal tone. Parents were also interviewed individually about their feelings about their own and their children's emotions, and children's intelligence was assessed. At Time 2, assessment of child outcomes were obtained, including observations of peer interaction, mother ratings of behavior problems and mother and teacher ratings of peer aggression, mother ratings of child physical illness, and measures of achievement. Results indicated that all Time 1 buffering factors protected children in face of marital conflict and dissolution.

  7. Liquid growth hormone: preservatives and buffers.

    PubMed

    Kappelgaard, Anne-Marie; Bojesen, Anders; Skydsgaard, Karsten; Sjögren, Ingrid; Laursen, Torben

    2004-01-01

    Growth hormone (GH) treatment is a successful medical therapy for children and adults with GH deficiency as well as for growth retardation due to chronic renal disease, Turner syndrome and in children born small for gestational age. For all of these conditions, treatment is long term and patients receive daily subcutaneous injections of GH for many years. Patient compliance is therefore of critical importance to ensure treatment benefit. One of the major factors influencing compliance is injection pain. Besides the injection device used, pain perception and local tissue reaction following injection are dependent on the preservative used in the formulation and the concentration of GH. Injection pain may also be related to the buffer substance and injection volume. A liquid formulation of GH, Norditropi SimpleXx, has been developed that dispenses with the need for reconstitution before administration. The formulation uses phenol (3 mg/ml) as a preservative (to protect product from microbial degradation or contamination) and histidine as a buffer. Alternative preservatives used in other GH formulations include m-cresol (9 mg/ml) and benzyl alcohol (3-9 mg/ml). Buffering agents include citrate and phosphate. Phenol has been successfully used as a preservative in drug formulations for more than 50 years and is considered a safe and effective agent which complies with strict international requirements for preservatives in drug formulations. In toxicological studies, no or only mild local reactions have been observed following subcutaneous administration of phenol (7.5 mg/ml), m-cresol (3-4 mg/ml) and benzyl alcohol (9 mg/ml). No general toxicity reactions were observed after subcutaneous administration of these agents. Clinical evaluation of the preservatives and buffers used in Norditropin SimpleXx showed that pain perception was similar between formulations containing phenol and benzyl alcohol, whereas m-cresol was associated with more painful injections than benzyl

  8. Baroreflex buffering and susceptibility to vasoactive drugs

    NASA Technical Reports Server (NTRS)

    Jordan, Jens; Tank, Jens; Shannon, John R.; Diedrich, Andre; Lipp, Axel; Schroder, Christoph; Arnold, Guy; Sharma, Arya M.; Biaggioni, Italo; Robertson, David; Luft, Friedrich C.

    2002-01-01

    BACKGROUND: The overall effect of vasoactive drugs on blood pressure is determined by a combination of the direct effect on vascular tone and an indirect baroreflex-mediated effect, a baroreflex buffering of blood pressure. Differences in baroreflex function affect the responsiveness to vasoactive medications, particularly baroreflex buffering of blood pressure; however, the magnitude is not known. METHODS AND RESULTS: We characterized baroreflex function and responses to vasoactive drugs in patients with idiopathic orthostatic intolerance, patients with essential hypertension, patients with monogenic hypertension and brachydactyly, patients with multiple system atrophy, and control subjects. We used phenylephrine sensitivity during ganglionic blockade as a measure of baroreflex buffering. Phenylephrine (25 microg) increased systolic blood pressure 6+/-1.6 mm Hg in control subjects, 6+/-1.1 mm Hg in orthostatic intolerance patients, 18+/-3.9 mm Hg in patients with essential hypertension, 31+/-3.4 mm Hg in patients with monogenic hypertension, and 25+/-3.4 mm Hg in patients with multiple system atrophy. Similar differences in sensitivities between groups were observed with nitroprusside. The sensitivity to vasoactive drugs was highly correlated with baroreflex buffering function and to a lesser degree with baroreflex control of heart rate. In control subjects, sensitivities to nitroprusside and phenylephrine infusions were correlated with baroreflex heart rate control and sympathetic nerve traffic. CONCLUSIONS: Our findings are consistent with an important effect of baroreflex blood pressure buffering on the sensitivity to vasoactive drugs. They suggest that even moderate changes in baroreflex function may have a substantial effect on the sensitivity to vasoactive medications.

  9. Capillary-Channeled Polymer (C-CP) Fibers as a Stationary Phase for Sample Clean-Up of Protein Solutions for Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Manard, Benjamin T.; Marcus, R. Kenneth

    2012-08-01

    Capillary-channeled polymer (C-CP) fibers are employed in a micropipette tip format to affect a stationary phase for the solid phase extraction (SPE) of proteins from buffer solutions prior to MALDI-MS analysis. Proteins readily adsorb to the polypropylene (PP) C-CP fibers while buffer species are easily washed off the tips using DI-H2O. Elution of the solutes is achieved with an aliquot of 50:50 ACN:H2O, which is compatible with the subsequent spotting on the MALDI target with the matrix solution. Lysozyme and cytochrome c are used as test species, with a primary buffer composition of 100 mM Tris-HCl. In this case, direct MALDI-MS produces no discernible protein signals. SPE on the C-CP fibers yields high fidelity mass spectra for 1 μL sample volumes. Limits of detection for cytochrome c in 100 mM Tris-HCl are on the order of 40 nM. Extraction of cytochrome c from buffer concentrations of up to 1 M Tris-HCl, provides signal recoveries that are suppressed by only ~50 % versus neat protein solutions. Finally, extraction of 3.1 μM cytochrome c from a synthetic urine matrix exhibits excellent recovery.

  10. Systematic Investigation of Key Survival and Growth Pathways in Breast Cancer

    DTIC Science & Technology

    2011-09-01

    lysed in NETN buffer (20 mM Tris-HCl, pH 8.0, 100 mM NaCl, 1 mM EDTA, 0.5% Nonidet P - 40 ) (with protease inhibitors) at 4 °C for 20 min. Crude lysates...bovine serum and 2 µgml−1 puromycin. The SFB–PTEN stable cells were lysed with NETN buffer (20mM Tris-HCl at pH 8.0, 100mM NaCl, 1mM EDTA, 0.5% Nonidet P ...percentages of BrdU positive cells were shown (n=3, ** means p ɘ.01, *** means p ɘ.001, mean±SEM). (B) Cell proliferation was increased in AMOTL2

  11. A Knock-in Reporter for a Novel AR-Targeted Therapy

    DTIC Science & Technology

    2016-05-01

    In brief, cells were lysed in RIPA buffer containing 50mM Tris-HCl, pH 7.4, 1% Nonidet P-40, 0.25% sodium deoxycholate, 150 mM NaCl, 1 mM EDTA, 1 mM...PMSF, and 1mM NaF, 1 mM Na3VO4 and protease inhibitor cocktail (Roche, Indianapolis, IN, USA), and then resolved in sodium dodecyl sulfate...cells irradiated with UV were lysed in modified RIPA buffer containing 50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium

  12. Stimulated low-frequency Raman scattering in a suspension of tobacco mosaic virus

    NASA Astrophysics Data System (ADS)

    Karpova, O. V.; Kudryavtseva, A. D.; Lednev, V. N.; Mironova, T. V.; Oshurko, V. B.; Pershin, S. M.; Petrova, E. K.; Tcherniega, N. V.; Zemskov, K. I.

    2016-08-01

    The interaction of laser pulses with tobacco mosaic virus (TMV) in Tris-HCl pH7.5 buffer and in water has been investigated. Ruby laser pulses of 20 ns duration have been used for excitation. The spectrum of the light passing through the sample was registered with the help of a Fabry-Perot interferometer. In the case of TMV in water we observed in the spectrum only one line of the exciting laser light, but for TMV in Tris-HCl pH7.5 buffer a second line appeared, corresponding to stimulated low-frequency Raman scattering (SLFRS) on the breathing radial mode of TMV. The frequency shift of the SLFRS by 2 cm-1 (60 GHz), the conversion efficiency and the threshold are measured for the first time to the best of our knowledge.

  13. Detection of Metastatic Potential in Breast Cancer by RhoC-GTPase and WISP3 Proteins

    DTIC Science & Technology

    2006-05-01

    NaCl, 1% Nonidet P40 , 2 mM MgCl2, 1µg/ml leupeptin, 1µg/ml aprotinin, 1 mM phenylmethylsulphonyl Breast Cancer Research Vol 6 No 2 Kleer et al. R112...research.com/content/7/6/R1080 R1084a buffer composed of 50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 1% Nonidet P40 , 1 mM Na3VO4, 1 mM phenylmethylsulphonyl fluoride...lysed in lysis buffer (50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 1% Nonidet P40 , 1 mM Na3VO4, 1 mM phenylmeth- ylsulphonyl fluoride, 1 µg/ml leupeptin, and

  14. Detection of Metastatic Potential in Breast Cancer by RhoC-GTPase and WISP3 Proteins

    DTIC Science & Technology

    2007-05-01

    Lex- ington, KY, USA). Western blot analysis Cells were lysed in lysis buffer (50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 1% Nonidet P40 , 1 mM Na3VO4, 1 mM...Available online http://breast-cancer-research.com/content/7/6/R1080 R1084a buffer composed of 50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 1% Nonidet ... P40 , 1 mM Na3VO4, 1 mM phenylmethylsulphonyl fluoride, 1 µg/ml leupeptin, and 10 µg/ml aprotinin. The IGF- 1R was immunoprecipitated overnight from

  15. Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers.

    PubMed

    Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y

    2016-12-01

    The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications.

  16. Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers

    NASA Astrophysics Data System (ADS)

    Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y.

    2016-02-01

    The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications.

  17. A new turn on coumarin-based fluorescence probe for Ga3 + detection in aqueous solution

    NASA Astrophysics Data System (ADS)

    Yan, Liqiang; Zhou, Yan; Du, Wenqi; Kong, Zhineng; Qi, Zhengjian

    2016-02-01

    The probe CT was synthesized and investigated as a novel label-free chemosensor for Ga3 + detection in water. Probe CT showed remarkable selectivity and sensitivity for Ga3 + in Tris-HCl aqueous buffer solution (pH 7.0). The chemosensor responded rapidly to Ga3 + with a 1:1 stoichiometry. Meanwhile, the unapparent changes of fluorescence lifetime decays suggest the turn-on process of probe CT by Ga3 + which appears to be a static mechanism.

  18. Buffered local anesthetics and epinephrine degradation.

    PubMed

    Murakami, C S; Odland, P B; Ross, B K

    1994-03-01

    Lidocaine with epinephrine is currently the most common local anesthetic agent used for facial soft tissue surgery. This combination is generally safe and effective in providing complete anesthesia and adequate hemostasis. Because epinephrine is unstable at physiologic pH, the commercial preparation is formulated with a low pH (3.5-5.5). Unfortunately, this acidic pH causes significant pain during infiltration. To reduce pain, clinicians sometimes buffer acidic local anesthetic agents with sodium bicarbonate. However, little is known about the stability of epinephrine when the pH of epinephrine is clinically altered. Using high pressure liquid chromatography (HPLC), epinephrine levels were measured after the addition of sodium bicarbonate. Our results indicate a significant amount of epinephrine degradation occurs in some of these specimens. Recommendations regarding the use of buffered local anesthetic agents are made.

  19. Spacecraft optical disk recorder memory buffer control

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1993-01-01

    This paper discusses the research completed under the NASA-ASEE summer faculty fellowship program. The project involves development of an Application Specific Integrated Circuit (ASIC) to be used as a Memory Buffer Controller (MBC) in the Spacecraft Optical Disk System (SODR). The SODR system has demanding capacity and data rate specifications requiring specialized electronics to meet processing demands. The system is being designed to support Gigabit transfer rates with Terabit storage capability. The complete SODR system is designed to exceed the capability of all existing mass storage systems today. The ASIC development for SODR consist of developing a 144 pin CMOS device to perform format conversion and data buffering. The final simulations of the MBC were completed during this summer's NASA-ASEE fellowship along with design preparations for fabrication to be performed by an ASIC manufacturer.

  20. Simple buffers for 3D STORM microscopy.

    PubMed

    Olivier, Nicolas; Keller, Debora; Rajan, Vinoth Sundar; Gönczy, Pierre; Manley, Suliana

    2013-06-01

    3D STORM is one of the leading methods for super-resolution imaging, with resolution down to 10 nm in the lateral direction, and 30-50 nm in the axial direction. However, there is one important requirement to perform this type of imaging: making dye molecules blink. This usually relies on the utilization of complex buffers, containing different chemicals and sensitive enzymatic systems, limiting the reproducibility of the method. We report here that the commercial mounting medium Vectashield can be used for STORM of Alexa-647, and yields images comparable or superior to those obtained with more complex buffers, especially for 3D imaging. We expect that this advance will promote the versatile utilization of 3D STORM by removing one of its entry barriers, as well as provide a more reproducible way to compare optical setups and data processing algorithms.

  1. Buffered explosions in steel pressure vessels

    SciTech Connect

    Glenn, L.A.

    1986-01-01

    The impulse delivered to the walls of a vessel containing an explosion will increase if material is placed between the walls and the charge. If the impulse application time is small in compared with the eigenperiod of the vessel, the wall stress will increase in direct proportion to the impulse. Conversely, if the application period can be extended beyond half the eigenperiod, the peak stress will be proportional to the ratio of the impulse to the delivery period. With powder or granular buffers, it is possible for the delivery period to increase faster than the impulse as the buffer mass is increased. This is the reason why certain powders, or porous materials, can provide stress reduction even below that observed by evacuating the space between the walls and the explosive. If the buffer material is to serve as an effective mitigator, it must collapse on shock loading to a final density that depends only weakly on pressure; the criterion is that the wave speed in the material that impacts the wall must be small comparison with the impact (particle) speed. This behavior apparently occurs with salt, at least for modest values of the charge parameter, but to a lesser extent with snow under the same conditions. The vermiculite data are comparable to the salt in the charge paramete region where the two overlap; with increasing explosive, however, the vermiculite appears to behave like the snow and its effectiveness as a mitigator rapidly diminishes. It is also clear that once the wave speed criterion is seriously violated, the use of a powder buffer will result in a higher wall stress than if only air filled the space between walls and charge. 5 refs.

  2. Wintering bird response to fall mowing of herbaceous buffers

    USGS Publications Warehouse

    Blank, P.J.; Parks, J.R.; Dively, G.P.

    2011-01-01

    Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland's Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing of buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), and White-throated Sparrows (Zonotrichia albicollis) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for wintering birds. ?? 2011 by the Wilson Ornithological Society.

  3. Complexation of buffer constituents with neutral complexation agents: part I. Impact on common buffer properties.

    PubMed

    Riesová, Martina; Svobodová, Jana; Tošner, Zdeněk; Beneš, Martin; Tesařová, Eva; Gaš, Bohuslav

    2013-09-17

    The complexation of buffer constituents with the complexation agent present in the solution can very significantly influence the buffer properties, such as pH, ionic strength, or conductivity. These parameters are often crucial for selection of the separation conditions in capillary electrophoresis or high-pressure liquid chromatography (HPLC) and can significantly affect results of separation, particularly for capillary electrophoresis as shown in Part II of this paper series (Beneš, M.; Riesová, M.; Svobodová, J.; Tesařová, E.; Dubský, P.; Gaš, B. Anal. Chem. 2013, DOI: 10.1021/ac401381d). In this paper, the impact of complexation of buffer constituents with a neutral complexation agent is demonstrated theoretically as well as experimentally for the model buffer system composed of benzoic acid/LiOH or common buffers (e.g., CHES/LiOH, TAPS/LiOH, Tricine/LiOH, MOPS/LiOH, MES/LiOH, and acetic acid/LiOH). Cyclodextrins as common chiral selectors were used as model complexation agents. We were not only able to demonstrate substantial changes of pH but also to predict the general complexation characteristics of selected compounds. Because of the zwitterion character of the common buffer constituents, their charged forms complex stronger with cyclodextrins than the neutral ones do. This was fully proven by NMR measurements. Additionally complexation constants of both forms of selected compounds were determined by NMR and affinity capillary electrophoresis with a very good agreement of obtained values. These data were advantageously used for the theoretical descriptions of variations in pH, depending on the composition and concentration of the buffer. Theoretical predictions were shown to be a useful tool for deriving some general rules and laws for complexing systems.

  4. Methyl Bromide Commodity Fumigation Buffer Zone Lookup Tables

    EPA Pesticide Factsheets

    Product labels for methyl bromide used in commodity and structural fumigation include requirements for buffer zones around treated areas. The information on this page will allow you to find the appropriate buffer zone for your planned application.

  5. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Boundary pillars and buffer zones. 3931... AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones. (a... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  6. Vegetated buffer management practice to improve surface water quality

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Zhang, X.; Liu, X.

    2007-12-01

    Vegetated buffer best management practices (BMPs) installed in agricultural landscapes have been suggested as promising candidate tactics to reduce erosion and offsite transportation of agrochemicals. A wide range of vegetated buffer management practices have been installed in many areas to reduce agrochemical loss from applied fields, to filter sediments from tailwaters, and to deter their transportation to water bodies. This presentation will focus on reviewing vegetated buffers and their efficacies in reducing agrochemical offsite movements, with a discussion on the major factors influencing BMP efficacy. Percent removal by various BMPs ranged from 16.7 to 100% for sediments, 29 to 98% for nitrogen, 1 to 100% for phosphorus, and 27 to 100% for pesticides, depending on the setting. Preliminary meta-analyses on the data obtained from the literature review showed that vegetated buffers were mostly effective in removing sediment, followed by pesticides and nutrients. BMP efficacy is mainly influenced by buffer width, buffer slope, rainfall and vegetation. As for sediment reduction, the results based on the limited data showed that buffer width and buffer slope are two major factors influencing mitigation efficacy of vegetated buffers. The results also showed that a design with 10-m width and a 9% slope optimizes the sediment trapping capability of vegetated buffers. The meta-analysis results of this study could provide specific recommendations such as buffer width and slope for future vegetated buffer BMP construction to increase soil and water conservation.

  7. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  8. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  9. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  10. The distribution of saliva buffer values in schoolchildren.

    PubMed

    Wikner, S; Moum, I

    1986-01-01

    Buffer capacity of stimulated saliva was estimated by Dentobuff in 1596 7-15 years old schoolchildren. 39.7% of the children had a high, 39.9% a low and 20.4% an intermediate buffer capacity. No significant differences between the distributions in different ages were recorded and the mean buffer values did not differ significantly between the age-groups.

  11. Buffer for a gamma-insensitive optical sensor with gas and a buffer assembly

    DOEpatents

    Kruger, H.W.

    1994-05-10

    A buffer assembly is disclosed for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode. 7 figures.

  12. Buffer for a gamma-insensitive optical sensor with gas and a buffer assembly

    DOEpatents

    Kruger, Hans W.

    1994-01-01

    A buffer assembly for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode.

  13. k(+)-buffer: An Efficient, Memory-Friendly and Dynamic k-buffer Framework.

    PubMed

    Vasilakis, Andreas-Alexandros; Papaioannou, Georgios; Fudos, Ioannis

    2015-06-01

    Depth-sorted fragment determination is fundamental for a host of image-based techniques which simulates complex rendering effects. It is also a challenging task in terms of time and space required when rasterizing scenes with high depth complexity. When low graphics memory requirements are of utmost importance, k-buffer can objectively be considered as the most preferred framework which advantageously ensures the correct depth order on a subset of all generated fragments. Although various alternatives have been introduced to partially or completely alleviate the noticeable quality artifacts produced by the initial k-buffer algorithm in the expense of memory increase or performance downgrade, appropriate tools to automatically and dynamically compute the most suitable value of k are still missing. To this end, we introduce k(+)-buffer, a fast framework that accurately simulates the behavior of k-buffer in a single rendering pass. Two memory-bounded data structures: (i) the max-array and (ii) the max-heap are developed on the GPU to concurrently maintain the k-foremost fragments per pixel by exploring pixel synchronization and fragment culling. Memory-friendly strategies are further introduced to dynamically (a) lessen the wasteful memory allocation of individual pixels with low depth complexity frequencies, (b) minimize the allocated size of k-buffer according to different application goals and hardware limitations via a straightforward depth histogram analysis and (c) manage local GPU cache with a fixed-memory depth-sorting mechanism. Finally, an extensive experimental evaluation is provided demonstrating the advantages of our work over all prior k-buffer variants in terms of memory usage, performance cost and image quality.

  14. Branch target buffer design and optimization

    NASA Technical Reports Server (NTRS)

    Perleberg, Chris H.; Smith, Alan J.

    1993-01-01

    Consideration is given to two major issues in the design of branch target buffers (BTBs), with the goal of achieving maximum performance for a given number of bits allocated to the BTB design. The first issue is BTB management; the second is what information to keep in the BTB. A number of solutions to these problems are reviewed, and various optimizations in the design of BTBs are discussed. Design target miss ratios for BTBs are developed, making it possible to estimate the performance of BTBs for real workloads.

  15. Spacecraft optical disk recorder memory buffer control

    NASA Technical Reports Server (NTRS)

    Hodson, Robert F.

    1992-01-01

    The goal of this project is to develop an Application Specific Integrated Circuit (ASIC) for use in the control electronics of the Spacecraft Optical Disk Recorder (SODR). Specifically, this project is to design an extendable memory buffer controller ASIC for rate matching between a system Input/Output port and the SODR's device interface. The aforementioned goal can be partitioned into the following sub-goals: (1) completion of ASIC design and simulation (on-going via ASEE fellowship); (2) ASIC Fabrication (at ASIC manufacturer); and (3) ASIC Testing (NASA/LaRC, Christopher Newport University).

  16. Seasonal buffering of atmospheric pressure on Mars

    NASA Technical Reports Server (NTRS)

    Dzurisin, D.; Ingersoll, A. P.

    1975-01-01

    An isothermal reservoir of carbon dioxide in gaseous contact with the Martian atmosphere would reduce the amplitude and advance the phase of global atmospheric pressure fluctuations caused by seasonal growth and decline of polar CO2 frost caps. Adsorbed carbon dioxide in the upper roughly 10 m of Martian regolith is sufficient to buffer the present atmosphere on a seasonal basis. Available observations and related polar cap models do not confirm or refute the operation of such a mechanism. Implications for the amplitude and phase of seasonal pressure fluctuations are subject to direct test by the upcoming Viking mission to Mars.

  17. Lightwave coupler utilizing a tapered buffer layer.

    PubMed

    Kishioka, K

    1988-06-01

    We discuss the performance of a lightwave coupler utilizing a tapered buffer layer. The coupler with a ridge waveguide is fabricated on a glass substrate and high coupling efficiencies of 75% and 50% are measured for the operations of coupling from the waveguide to a light beam and from the laser beam into the waveguide, respectively. Further, experimental results of the rigid connection between the optical fiber and the waveguide are demonstrated. We also describe how the coupler differs from the conventional tapered guiding-layer coupler.

  18. Buffer layers and articles for electronic devices

    DOEpatents

    Paranthaman, Mariappan P.; Aytug, Tolga; Christen, David K.; Feenstra, Roeland; Goyal, Amit

    2004-07-20

    Materials for depositing buffer layers on biaxially textured and untextured metallic and metal oxide substrates for use in the manufacture of superconducting and other electronic articles comprise RMnO.sub.3, R.sub.1-x A.sub.x MnO.sub.3, and combinations thereof; wherein R includes an element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, and A includes an element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Ra.

  19. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2005-05-01

    Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extent to which flow concentration affects buffer efficiency. Recommendations are presented for the design of adaptive-width buffers.

  20. Analysis of a hybrid-undirectional buffer strip laminate

    NASA Technical Reports Server (NTRS)

    Dharani, L. R.; Goree, J. G.

    1983-01-01

    A method of analysis capable of predicting accurately the fracture behavior of a unidirectional composite laminate containing symmetrically placed buffer strips is presented. As an example, for a damaged graphite/epoxy laminate, the results demonstrate the manner in which to select the most efficient combination of buffer strip properties necessary to inhibit crack growth. Ultimate failure of the laminate after the arrest can occur under increasing load either by continued crack extension through the buffer strips or the crack can jump the buffer strips. For some typical hybrid materials it is found that a buffer strip spacing to width ratio of about four to one is the most efficient.

  1. Analysis of a hybrid, unidirectional buffer strip laminate

    NASA Technical Reports Server (NTRS)

    Dharani, L. R.; Goree, J. G.

    1983-01-01

    A method of analysis capable of predicting accurately the fracture behavior of a unidirectional composite laminate containing symmetrically placed buffer strips is presented. As an example, for a damaged graphite/epoxy laminate, the results demonstrate the manner in which to select the most efficient combination of buffer strip properties necessary to inhibit crack growth. Ultimate failure of the laminate after crack arrest can occur under increasing load either by continued crack extension through the buffer strips or the crack can jump the buffer strips. For some typical hybrid materials it is found that a buffer strip spacing-to-width ratio of about four to one is the most efficient.

  2. A Buffer Management Issue in Designing SSDs for LFSs

    NASA Astrophysics Data System (ADS)

    Kim, Jaegeuk; Seol, Jinho; Maeng, Seungryoul

    This letter introduces a buffer management issue in designing SSDs for log-structured file systems (LFSs). We implemented a novel trace-driven SSD simulator in SystemC language, and simulated several SSD architectures with the NILFS2 trace. From the results, we give two major considerations related to the buffer management as follows. (1) The write buffer is used as a buffer not a cache, since all write requests are sequential in NILFS2. (2) For better performance, the main architectural factor is the bus bandwidth, but 332MHz is enough. Instead, the read buffer makes a key role in performance improvement while caching data. To enhance SSDs, accordingly, it is an effective way to make efficient read buffer management policies, and one of the examples is tracking the valid data zone in NILFS2, which can increase the data hit ratio in read buffers significantly.

  3. Buffering Mechanism of the Atmospheric Oxidation Capacity

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Gromov, S.; Pozzer, A.; Taraborrelli, D.

    2015-12-01

    Millions of tons pollutant and greenhouse gases per year are emitted and subsequently removed from the atmosphere through oxidation reactions. The oxidation products are typically more soluble or have a low vapor pressure so that they become subject to deposition processes. The atmospheric oxidation capacity is primarily maintained by hydroxyl (OH) radicals, which initiate reaction chains that can recycle or destroy OH. Key questions are if the oxidation capacity is affected by growing pollution emissions, to what extent it is buffered by OH recycling, and how regions with specific photochemical and pollution characteristics act together through atmospheric transport at a global scale. While previous generations atmospheric chemistry-transport models have discounted OH recycling with schemes that lumped or truncated reaction sequences, we present an approach that does justice to the intricate interactions between reactive carbon, nitrogen and oxygen species. This gives rise to a global buffering mechanism of the oxidation capacity that explains the observed small variability of methane and other gases that are removed by reaction with OH.

  4. Vegetative buffer strips for reducing herbicide transport in runoff: effects of season, vegetation, and buffer width

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of vegetative buffer strip (VBS) width, vegetation, and season of the year on herbicide transport in runoff has not been well documented for runoff prone soils. A multi-year replicated plot-scale study was conducted on an eroded claypan soil with the following objectives: 1) assess the ef...

  5. Buffer allocation in an ATM switch with output buffer and speed constraints

    NASA Astrophysics Data System (ADS)

    Gupta, Anil K.; Georganas, N. D.

    A synchronous nonblocking N times N switch for asynchronous transfer mode (ATM) networks or high speed packet switching networks transporting fixed length packets called cells is considered. Such a switch with output queuing achieves the optimal performance, however it requires the switch fabric to work at the speed of N. In practice the switch may operate L times faster than the input/output trunk. It is assumed that queues at each output port have a limited buffer space and whenever an output queue is full, the back-pressure is applied and the packets are retained at the head of the input queues. The upper bound on the packet loss probability at the input queues in such a switch are computed. To achieve a given packet loss rate, the switch with L equals 2 requires almost the same amount of input and output buffers as with L equals 4 up to 70 percent input load, but as the load increases beyond 70 percent the switch with L equals 4 would require more output buffers and less input buffers in comparison with a switch operating at L equals 2. The performance of a switch with L equals 3 is very similar to that for L equals 4 and is not considered.

  6. Purification of α-glucosidase from mouse intestine by countercurrent chromatography coupled with a reverse micelle solvent system.

    PubMed

    He, Kai; Zou, Zongyao; Hu, Yinran; Yang, Yong; Xiao, Yubo; Gao, Pincao; Li, Xuegang; Ye, Xiaoli

    2016-02-01

    Countercurrent chromatography coupled with a reverse micelle solvent was applied to separate α-glucosidase, which is stable at pH 6.0-8.8, 15-50°C. The separation conditions are as follows: stationary phase: pH 4.0 Tris-HCl buffer phase containing 50 mM Tris-HCl and 50 mM KCl; mobile phase A: isooctane containing 50 mM anionic surfactant sodium di(2-ethylhexyl)sulfosuccinate; mobile phase B: 50 mM Tris-HCl buffer containing 500 mM KCl (pH 8.0); In total, 25 mL (23.9 mg) crude enzyme was injected through the injection valve, the enzymatic reaction and sodium dodecylsulfate polyacrylamide gel electrophoresis results imply that the activity of purified α-glucosidase is 6.63-fold higher than that of the crude enzyme. Therefore, countercurrent chromatography coupled with a reverse micelle solvent is capable for protein separation and enrichment.

  7. Damage tolerance of woven graphite-epoxy buffer strip panels

    NASA Technical Reports Server (NTRS)

    Kennedy, John M.

    1990-01-01

    Graphite-epoxy panels with S glass buffer strips were tested in tension and shear to measure their residual strengths with crack-like damage. The buffer strips were regularly spaced narrow strips of continuous S glass. Panels were made with a uniweave graphite cloth where the S glass buffer material was woven directly into the cloth. Panels were made with different width and thickness buffer strips. The panels were loaded to failure while remote strain, strain at the end of the slit, and crack opening displacement were monitoring. The notched region and nearby buffer strips were radiographed periodically to reveal crack growth and damage. Except for panels with short slits, the buffer strips arrested the propagating crack. The strength (or failing strain) of the panels was significantly higher than the strength of all-graphite panels with the same length slit. Panels with wide, thick buffer strips were stronger than panels with thin, narrow buffer strips. A shear-lag model predicted the failing strength of tension panels with wide buffer strips accurately, but over-estimated the strength of the shear panels and the tension panels with narrow buffer strips.

  8. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals.

    PubMed

    McMahon, Shane M; Chang, Che-Wei; Jackson, Meyer B

    2016-03-01

    Cytosolic Ca(2+) buffers bind to a large fraction of Ca(2+) as it enters a cell, shaping Ca(2+) signals both spatially and temporally. In this way, cytosolic Ca(2+) buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca(2+) entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca(2+) buffers in controlling pituitary Ca(2+) signaling is poorly understood. Here, cytosolic Ca(2+) buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca(2+) indicator fluo-8 revealed stepwise increases in free Ca(2+) after a series of brief depolarizing pulses in rapid succession. These Ca(2+) increments grew larger as free Ca(2+) rose to saturate the cytosolic buffers and reduce the availability of Ca(2+) binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5-4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca(2+) buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca(2+) signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones.

  9. Is bicarbonate buffer suitable as a dissolution medium?

    PubMed

    Boni, Julia Elisabeth; Brickl, Rolf Stefan; Dressman, Jennifer

    2007-10-01

    The objectives of this study were to compare two methods for the preparation of bicarbonate buffer, and to compare media prepared with bicarbonate buffer with commonly used biorelevant and pharmacopoeial media in terms of their suitability for dissolution testing. The various media were compared with regard to ease of preparation, robustness and reproducibility of composition. The dissolution of three formulations of a typical Biopharmaceutical Classification System Class II drug (BIXX) was compared in bicarbonate buffer, standard phosphate buffer, a biorelevant buffer (fasted-state simulating intestinal fluid, FaSSIF) and a modified FaSSIF prepared with bicarbonate buffer. The bicarbonate buffer used for dissolution testing was produced by supplying carbon dioxide to a saline solution (0.9% NaCl, to which 12 or 42 mmol NaOH had been added). The bicarbonate buffer had to be prepared in-situ, which proved to be time-consuming, and the pH stability of the bicarbonate buffer could only be maintained under constant CO2 supply. To minimize the mechanical stress caused by inflow and evaporation of gas, the carbon dioxide was supplied above the medium during the dissolution test. Despite taking these measures, use of bicarbonate buffer led to less reproducible dissolution results than the phosphate buffers commonly used to prepare compendial media and FaSSIF, with coefficient of variance values 1.5- to 5-times higher in bicarbonate buffer. It was concluded that although a bicarbonate buffer system would be physiologically relevant for the fasted state in the small intestine, its suitability for dissolution testing is restricted by lack of practicability and poor reproducibility of results.

  10. Microscopic optical buffering in a harmonic potential

    PubMed Central

    Sumetsky, M.

    2015-01-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices. PMID:26689546

  11. Thermally programmable pH buffers.

    PubMed

    Van Gough, Dara; Bunker, Bruce C; Roberts, Mark E; Huber, Dale L; Zarick, Holly F; Austin, Mariah J; Wheeler, Jill S; Moore, Diana; Spoerke, Erik D

    2012-11-01

    Many reactions in both chemistry and biology rely on the ability to precisely control and fix the solution concentrations of either protons or hydroxide ions. In this report, we describe the behavior of thermally programmable pH buffer systems based on the copolymerization of varying amounts of acrylic acid (AA) groups into N-isopropylacrylamide polymers. Because the copolymers undergo phase transitions upon heating and cooling, the local environment around the AA groups can be reversibly switched between hydrophobic and hydrophilic states affecting the ionization behavior of the acids. Results show that moderate temperature variations can be used to change the solution pH by two units. However, results also indicate that the nature of the transition and its impact on the pH values are highly dependent on the AA content and the degree of neutralization.

  12. Surface Treatments of Nb by Buffered Electropolishing

    SciTech Connect

    Wu, Andy T.; Rimmer, Robert A.; Ciovati, Gianluigi; Manus, Robert L.; Reece, Charles E.; Williams, J. S.; Eozénou, F.; Jin, S.; Wang, E.

    2009-11-01

    Buffered electropolishing (BEP) is a Nb surface treatment technique developed at Jefferson Lab1. Experimental results obtained from flat Nb samples show2-4 that BEP can produce a surface finish much smoother than that produced by the conventional electropolishing (EP), while Nb removal rate can be as high as 4.67 μm/min. This new technique has been applied to the treatments of Nb SRF single cell cavity employing a vertical polishing system5 constructed at JLab as well as a horizontal polishing system at CEA Saclay. Preliminary results show that the accelerating gradient can reach 32 MV/m for a large grain cavity and 26.7 MV/m for a regular grain cavity. In this presentation, the latest progresses from the international collaboration between Peking University, CEA Saclay, and JLab on BEP will be summarized.

  13. Biofiltration with bicarbonate as dialysate buffer.

    PubMed

    Rizzelli, S; Alfonso, L; Corlianò, C; Patruno, P; Sozzo, E; Mastrangelo, F

    1986-12-01

    The biofiltration with bicarbonate as dialysate buffer (BiBF) was used in 10 patients on RDT: the patients were treated for 10 months on standard BF and for 10 months on BiBF. The amount of fluid infused varied between 3 and 5 liters and Na-bicarbonate (100 mEq/h) was infused during BF. The dialytic protocol was 3 hours every other day. Cardiovascular stability, waste molecules and acid-base balance were investigated. No differences in vascular stability and no significant changes in the waste-molecules concentrations were found. Both protocols correct the metabolic acidosis; however, in standard BF 50% of patients showed acute hypocapnia at the end of dialysis.

  14. Hydrological heterogeneity in agricultural riparian buffer strips

    NASA Astrophysics Data System (ADS)

    Hénault-Ethier, Louise; Larocque, Marie; Perron, Rachel; Wiseman, Natalie; Labrecque, Michel

    2017-03-01

    Riparian buffer strips (RBS) may protect surface water and groundwater in agricultural settings, although their effectiveness, observed in field-scale studies, may not extend to a watershed scale. Hydrologically-controlled leaching plots have often shown RBS to be effective at buffering nutrients and pesticides, but uncontrolled field studies have sometimes suggested limited effectiveness. The limited RBS effectiveness may be explained by the spatiotemporal hydrological heterogeneity near non-irrigated fields. This hypothesis was tested in conventional corn and soy fields in the St. Lawrence Lowlands of southern Quebec (Canada), where spring melt brings heavy and rapid runoff, while summer months are hot and dry. One field with a mineral soil (Saint-Roch-de-l'Achigan) and another with an organic-rich soil (Boisbriand) were equipped with passive runoff collectors, suction cup lysimeters, and piezometers placed before and after a 3 m-wide RBS, and monitored from 2011 to 2014. Soil topography of the RBS was mapped to a 1 cm vertical precision and a 50 cm sampling grid. On average, surface runoff intersects the RBS perpendicularly, but is subject to substantial local heterogeneity. Groundwater saturates the root zones, but flows little at the time of snowmelt. Groundwater flow is not consistently perpendicular to the RBS, and may reverse, flowing from stream to field under low water flow regimes with stream-aquifer connectivity, thus affecting RBS effectiveness calculations. Groundwater flow direction can be influenced by stratigraphy, local soil hydraulic properties, and historical modification of the agricultural stream beds. Understanding the spatiotemporal heterogeneity of surface and groundwater flows is essential to correctly assess the effectiveness of RBS in intercepting agro-chemical pollution. The implicit assumption that water flows across vegetated RBS, from the field to the stream, should always be verified.

  15. Natriuretic peptides buffer renin-dependent hypertension.

    PubMed

    Demerath, Theo; Staffel, Janina; Schreiber, Andrea; Valletta, Daniela; Schweda, Frank

    2014-06-15

    The renin-angiotensin-aldosterone system and cardiac natriuretic peptides [atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP)] are opposing control mechanisms for arterial blood pressure. Accordingly, an inverse relationship between plasma renin concentration (PRC) and ANP exists in most circumstances. However, PRC and ANP levels are both elevated in renovascular hypertension. Because ANP can directly suppress renin release, we used ANP knockout (ANP(-/-)) mice to investigate whether high ANP levels attenuate the increase in PRC in response to renal hypoperfusion, thus buffering renovascular hypertension. ANP(-/-) mice were hypertensive and had reduced PRC compared with that in wild-type ANP(+/+) mice under control conditions. Unilateral renal artery stenosis (2-kidney, 1-clip) for 1 wk induced similar increases in blood pressure and PRC in both genotypes. Unexpectedly, plasma BNP concentrations in ANP(-/-) mice significantly increased in response to two-kidney, one-clip treatment, potentially compensating for the lack of ANP. In fact, in mice lacking guanylyl cyclase A (GC-A(-/-) mice), which is the common receptor for both ANP and BNP, renovascular hypertension was markedly augmented compared with that in wild-type GC-A(+/+) mice. However, the higher blood pressure in GC-A(-/-) mice was not caused by disinhibition of the renin system because PRC and renal renin synthesis were significantly lower in GC-A(-/-) mice than in GC-A(+/+) mice. Thus, natriuretic peptides buffer renal vascular hypertension via renin-independent effects, such as vasorelaxation. The latter possibility is supported by experiments in isolated perfused mouse kidneys, in which physiological concentrations of ANP and BNP elicited renal vasodilatation and attenuated renal vasoconstriction in response to angiotensin II.

  16. Cost of riparian buffer zones: A comparison of hydrologically adapted site-specific riparian buffers with traditional fixed widths

    NASA Astrophysics Data System (ADS)

    Tiwari, T.; Lundström, J.; Kuglerová, L.; Laudon, H.; Öhman, K.; Ågren, A. M.

    2016-02-01

    Traditional approaches aiming at protecting surface waters from the negative impacts of forestry often focus on retaining fixed width buffer zones around waterways. While this method is relatively simple to design and implement, it has been criticized for ignoring the spatial heterogeneity of biogeochemical processes and biodiversity in the riparian zone. Alternatively, a variable width buffer zone adapted to site-specific hydrological conditions has been suggested to improve the protection of biogeochemical and ecological functions of the riparian zone. However, little is known about the monetary value of maintaining hydrologically adapted buffer zones compared to the traditionally used fixed width ones. In this study, we created a hydrologically adapted buffer zone by identifying wet areas and groundwater discharge hotspots in the riparian zone. The opportunity cost of the hydrologically adapted riparian buffer zones was then compared to that of the fixed width zones in a meso-scale boreal catchment to determine the most economical option of designing riparian buffers. The results show that hydrologically adapted buffer zones were cheaper per hectare than the fixed width ones when comparing the total cost. This was because the hydrologically adapted buffers included more wetlands and low productive forest areas than the fixed widths. As such, the hydrologically adapted buffer zones allows more effective protection of the parts of the riparian zones that are ecologically and biogeochemically important and more sensitive to disturbances without forest landowners incurring any additional cost than fixed width buffers.

  17. The Multimission Image Processing Laboratory's virtual frame buffer interface

    NASA Technical Reports Server (NTRS)

    Wolfe, T.

    1984-01-01

    Large image processing systems use multiple frame buffers with differing architectures and vendor supplied interfaces. This variety of architectures and interfaces creates software development, maintenance and portability problems for application programs. Several machine-dependent graphics standards such as ANSI Core and GKS are available, but none of them are adequate for image processing. Therefore, the Multimission Image Processing laboratory project has implemented a programmer level virtual frame buffer interface. This interface makes all frame buffers appear as a generic frame buffer with a specified set of characteristics. This document defines the virtual frame uffer interface and provides information such as FORTRAN subroutine definitions, frame buffer characteristics, sample programs, etc. It is intended to be used by application programmers and system programmers who are adding new frame buffers to a system.

  18. PVA-based tunable buffering membranes for isoelectric trapping separations.

    PubMed

    Fleisher-Craver, Helen C; Vigh, Gyula

    2008-11-01

    PVA-based buffering membranes with tunable pH values were prepared on a PVA substrate by reacting PVA, glycerol-1,3-diglycidyl ether, -NH2 group-containing buffers and -NH2 group-containing titrants in the presence of sodium hydroxide. The pH of the buffering membranes could be tuned in the 3buffering capacities in excess of 100 mM. Detailed recipes for the preparation of six families of buffering membranes are tabulated and provided as Supporting Information. The buffering membranes were used to trap and desalt ampholyte solutions and separate proteins having a DeltapI as small as 0.1. The membranes were mechanically and hydrolytically stable and could be stored, even in 10

  19. Buffer layer optimization for high efficiency CIGS solar cells

    NASA Astrophysics Data System (ADS)

    Severino, N.; Bednar, N.; Adamovic, N.

    2016-10-01

    This work presents a study concerning the numerical optimization of a buffer layer for high efficiency CIGS solar cells. The dependence of the solar cell properties on the buffer layer material, the layer thickness, the type and density of defects within the same layer were numerically investigated and analysed. Promising results were obtained with alternative Cd-free buffer layers (ZnSnO, InS and ZnS) in place of the standard CdS.

  20. Development of buffers for fast semidry transfer of proteins.

    PubMed

    Garić, Dušan; Humbert, Laure; Fils-Aimé, Nadège; Korah, Juliana; Zarfabian, Yasaman; Lebrun, Jean-Jacques; Ali, Suhad

    2013-10-15

    Western blot is an extensively used method for protein detection in cell biology. To optimize this procedure, here we examined a panel of buffers for their ability to efficiently transfer proteins from SDS-polyacrylamide gels onto nitrocellulose membranes in a short 12-min period, designated here as fast semidry transfer. Our results show for the first time that HEPES- and HEPPS/EPPS-based buffers represent the most efficient buffers for fast semidry transfer.

  1. Grass buffers for playas in agricultural landscapes: A literature synthesis

    USGS Publications Warehouse

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    Future research should entail multiple-scale approaches at regional, wetland-complex, and individual watershed scales. Information needs include direct measures of buffer effectiveness in ‘real-world’ systems, refinement and field tests of buffer-effectiveness models, how buffers may affect floral and faunal communities of playas, and basic ecological information on playa function and playa wildlife ecology. Understanding how wildlife communities respond to patch size and habitat fragmentation is crucial for addressing questions regarding habitat quality of grass buffers in playa systems.

  2. Tris buffer modulates polydopamine growth, aggregation, and paramagnetic properties.

    PubMed

    Della Vecchia, Nicola Fyodor; Luchini, Alessandra; Napolitano, Alessandra; D'Errico, Gerardino; Vitiello, Giuseppe; Szekely, Noemi; d'Ischia, Marco; Paduano, Luigi

    2014-08-19

    Despite the growing technological interest of polydopamine (dopamine melanin)-based coatings for a broad variety of applications, the factors governing particle size, shape, and electronic properties of this bioinspired multifunctional material have remained little understood. Herein, we report a detailed characterization of polydopamine growth, particle morphology, and paramagnetic properties as a function of dopamine concentration and nature of the buffer (pH 8.5). Dynamic Light Scattering data revealed an increase in the hydrodynamic radii (Rh) of melanin particles with increasing dopamine concentration in all buffers examined, especially in phosphate buffer. Conversely, a marked inhibition of particle growth was apparent in Tris buffer, with Rh remaining as low as <100 nm during polymerization of 0.5 mM dopamine. Small angle neutron scattering data suggested formation of bidimensional structures in phosphate or bicarbonate buffers, while apparently three-dimensional fractal objects prevailed in Tris buffer. Finally, electron paramagnetic resonance spectra revealed a broader signal amplitude with a peculiar power saturation decay profile for polydopamine samples prepared in Tris buffer, denoting more homogeneous paramagnetic centers with respect to similar samples obtained in phosphate and bicarbonate buffers. Overall, these results disclose Tris buffer as an efficient modulator of polydopamine buildup and properties for the rational control and fine-tuning of melanin aggregate size, morphology, and free radical behavior.

  3. An assessment of buffer strips for improving damage tolerance

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.; Kennedy, J. M.

    1981-01-01

    Graphite/epoxy panels with buffer strips were tested in tension to measure their residual strength with crack-like damage. Panels were made with 45/0/-45/90(2S) and 45/0/450(2S) layups. The buffer strips were parallel to the loading directions. They were made by replacing narrow strips of the 0 deg graphite plies with strips of either 0 deg S-Glass/epoxy or Kevlar-49/epoxy on either a one for one or a two for one basis. In a third case, O deg graphite/epoxy was used as the buffer material and thin, perforated Mylar strips were placed between the 0 deg piles and the cross-plies to weaken the interfaces and thus to isolate the 0 deg plies. Some panels were made with buffer strips of different widths and spacings. The buffer strips arrested the cracks and increased the residual strengths significantly over those plain laminates without buffer strips. A shear-lag type stress analysis correctly predicted the effects of layups, buffer material, buffer strip width and spacing, and the number of plies of buffer material.

  4. Buffers affect the bending rigidity of model lipid membranes.

    PubMed

    Bouvrais, Hélène; Duelund, Lars; Ipsen, John H

    2014-01-14

    In biophysical and biochemical studies of lipid bilayers the influence of the used buffer is often ignored or assumed to be negligible on membrane structure, elasticity, or physical properties. However, we here present experimental evidence, through bending rigidity measurements performed on giant vesicles, of a more complex behavior, where the buffering molecules may considerably affect the bending rigidity of phosphatidylcholine bilayers. Furthermore, a synergistic effect on the bending modulus is observed in the presence of both salt and buffer molecules, which serves as a warning to experimentalists in the data interpretation of their studies, since typical lipid bilayer studies contain buffer and ion molecules.

  5. Solubilization of proteins: the importance of lysis buffer choice.

    PubMed

    Peach, Mandy; Marsh, Noelle; Miskiewicz, Ewa I; MacPhee, Daniel J

    2015-01-01

    The efficient extraction of proteins of interest from cells and tissues is not always straightforward. Here we demonstrate the differences in extraction of the focal adhesion protein Kindlin-2 from choriocarcinoma cells using NP-40 and RIPA lysis buffer. Furthermore, we demonstrate the use of a more denaturing urea/thiourea lysis buffer for solubilization, by comparing its effectiveness for solubilization of small heat-shock proteins from smooth muscle with the often utilized RIPA lysis buffer. Overall, the results demonstrate the importance of establishing the optimal lysis buffer for specific protein solubilization within the experimental workflow.

  6. Back contact buffer layer for thin-film solar cells

    DOEpatents

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

    A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

  7. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2004-05-01

    Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extend to which flow concentration affects buffer efficiency.

  8. Developing Suitable Buffers to Capture Transport Cycling Behavior

    PubMed Central

    Madsen, Thomas; Schipperijn, Jasper; Christiansen, Lars Breum; Nielsen, Thomas Sick; Troelsen, Jens

    2014-01-01

    The association between neighborhood built environment and cycling has received considerable attention in health literature over the last two decades, but different neighborhood definitions have been used and it is unclear which one is most appropriate. Administrative or fixed residential spatial units (e.g., home-buffer-based neighborhoods) are not necessarily representative for environmental exposure. An increased understanding of appropriate neighborhoods is needed. GPS cycling tracks from 78 participants for 7 days form the basis for the development and testing of different neighborhood buffers for transport cycling. The percentage of GPS points per square meter was used as indicator of the effectiveness of a series of different buffer types, including home-based network buffers, shortest route to city center buffers, and city center-directed ellipse-shaped buffers. The results show that GPS tracks can help us understand where people go and stay during the day, which can help us link built environment with cycling. Analysis showed that the further people live from the city center, the more elongated are their GPS tracks, and the better an ellipse-shaped directional buffer captured transport cycling behavior. In conclusion, we argue that in order to be able to link built environment factors with different forms of physical activity, we must study the most likely area people use. In this particular study, to capture transport cycling, with its relatively large radius of action, city center-directed ellipse-shaped buffers yielded better results than traditional home-based network buffer types. The ellipse-shaped buffer types could therefore be considered an alternative to more traditional buffers or administrative units in future studies of transport cycling behavior. PMID:24926478

  9. Diversity, Replication, Pathogenicity and Cell Biology of Crimean Congo Hemorrhagic Fever Virus

    DTIC Science & Technology

    2008-10-01

    Immunoadsorbents were then exhaus- tively washed with phosphate-buffered saline (PBS), emulsified directly in complete or incomplete Freund’s adjuvant...Lowe, S. E. Radford, and C. M. Dobson. 1990. Hen egg white lysozyme expressed in, and secreted from, Aspergillus niger is correctly processed and...phosphate-buffered saline (DPBS; Invitrogen) and then lysed with buffer consisting of 1% Triton X-100, 150 mM NaCl, 5 mM EDTA, 50 mM Tris-HCl pH 7.4, and

  10. Metabolic Signaling and Therapy of Lung Cancer

    DTIC Science & Technology

    2013-09-01

    Magic C18; Michrom BioResources). Peptides were resolved on a 110-min 1–100% buffer B gradient (buffer A¼ 0.1 mol l 1 acetic acid , Buffer B¼ 70...acetonitrile in 0.1mol l 1 acetic acid ) at a flow rate of 200mlmin 1 (1200 series; Agilent). The HPLC was coupled to a mass spectrometer (LTQ-Orbitrap...analogue was mixed with different concentrations of 2,3-BPG in reaction mixture containing 100 mM Tris-HCl ( pH 7.5). Fluorescence intensity of 2,3-BPG

  11. A wide bandwidth CCD buffer memory system

    NASA Technical Reports Server (NTRS)

    Siemens, K.; Wallace, R. W.; Robinson, C. R.

    1978-01-01

    A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. CCD shift register memories (8K bit) were used to construct a feasibility model 128 K-bit buffer memory system. Serial data that can have rates between 150 kHz and 4.0 MHz can be stored in 4K-bit, randomly-accessible memory blocks. Peak power dissipation during a data transfer is less than 7 W, while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. System expansion to accommodate parallel inputs or a greater number of memory blocks can be performed in a modular fashion. Since the control logic does not increase proportionally to increase in memory capacity, the power requirements per bit of storage can be reduced significantly in a larger system.

  12. Microbial Community Diversity in Agroforestry and Grass Buffer Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agroforesty and grass buffer systems have long been promoted as a soil conservation practice that yields many environmental benefits. Previous research has described the ability of buffer systems to retain nutrients, slow water flow and soil erosion, or mitigate the potentially harmful effects of e...

  13. Methods for improved growth of group III nitride buffer layers

    DOEpatents

    Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

    2014-07-15

    Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphology of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).

  14. Current isolating epitaxial buffer layers for high voltage photodiode array

    DOEpatents

    Morse, Jeffrey D.; Cooper, Gregory A.

    2002-01-01

    An array of photodiodes in series on a common semi-insulating substrate has a non-conductive buffer layer between the photodiodes and the semi-insulating substrate. The buffer layer reduces current injection leakage between the photodiodes of the array and allows optical energy to be converted to high voltage electrical energy.

  15. Dynamic Buffer Capacity in Acid-Base Systems.

    PubMed

    Michałowska-Kaczmarczyk, Anna M; Michałowski, Tadeusz

    The generalized concept of 'dynamic' buffer capacity βV is related to electrolytic systems of different complexity where acid-base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton-Robinson buffers, taken as examples.

  16. Improved pH buffering agent for sodium hypochlorite

    NASA Technical Reports Server (NTRS)

    Nash, J. R.; Veeder, L. N.

    1969-01-01

    Sodium citrate/citric acid was found to be an effective buffer for pH control when used with sodium hypochlorite. The mixture does not corrode aluminum. The buffer appears to form a type of conversion coating that may provide corrosion-resistant properties to aluminum in other applications.

  17. Replenishing data descriptors in a DMA injection FIFO buffer

    DOEpatents

    Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Cernohous, Bob R [Rochester, MN; Heidelberger, Philip [Cortlandt Manor, NY; Kumar, Sameer [White Plains, NY; Parker, Jeffrey J [Rochester, MN

    2011-10-11

    Methods, apparatus, and products are disclosed for replenishing data descriptors in a Direct Memory Access (`DMA`) injection first-in-first-out (`FIFO`) buffer that include: determining, by a messaging module on an origin compute node, whether a number of data descriptors in a DMA injection FIFO buffer exceeds a predetermined threshold, each data descriptor specifying an application message for transmission to a target compute node; queuing, by the messaging module, a plurality of new data descriptors in a pending descriptor queue if the number of the data descriptors in the DMA injection FIFO buffer exceeds the predetermined threshold; establishing, by the messaging module, interrupt criteria that specify when to replenish the injection FIFO buffer with the plurality of new data descriptors in the pending descriptor queue; and injecting, by the messaging module, the plurality of new data descriptors into the injection FIFO buffer in dependence upon the interrupt criteria.

  18. Mitigation of substrate defects in reticles using multilayer buffer layers

    DOEpatents

    Mirkarimi, Paul B.; Bajt, Sasa; Stearns, Daniel G.

    2001-01-01

    A multilayer film is used as a buffer layer to minimize the size of defects on a reticle substrate prior to deposition of a reflective coating on the substrate. The multilayer buffer layer deposited intermediate the reticle substrate and the reflective coating produces a smoothing of small particles and other defects on the reticle substrate. The reduction in defect size is controlled by surface relaxation during the buffer layer growth process and by the degree of intermixing and volume contraction of the materials at the multilayer interfaces. The buffer layers are deposited at near-normal incidence via a low particulate ion beam sputtering process. The growth surface of the buffer layer may also be heated by a secondary ion source to increase the degree of intermixing and improve the mitigation of defects.

  19. Thin film photovoltaic devices with a minimally conductive buffer layer

    DOEpatents

    Barnes, Teresa M.; Burst, James

    2016-11-15

    A thin film photovoltaic device (100) with a tunable, minimally conductive buffer (128) layer is provided. The photovoltaic device (100) may include a back contact (150), a transparent front contact stack (120), and an absorber (140) positioned between the front contact stack (120) and the back contact (150). The front contact stack (120) may include a low resistivity transparent conductive oxide (TCO) layer (124) and a buffer layer (128) that is proximate to the absorber layer (140). The photovoltaic device (100) may also include a window layer (130) between the buffer layer (128) and the absorber (140). In some cases, the buffer layer (128) is minimally conductive, with its resistivity being tunable, and the buffer layer (128) may be formed as an alloy from a host oxide and a high-permittivity oxide. The high-permittivity oxide may further be chosen to have a bandgap greater than the host oxide.

  20. Adsorption behavior of ferritin and buffer components, buffer agents and salts, onto silane-coupled silicon substrate.

    PubMed

    Fukuta, Megumi; Yamashita, Ichiro

    2010-01-01

    Fixation of ferritin using amino-silane modified substrates is effective, but salt and alkali ions of the buffer can contaminate substrates, inhibiting the sensing and fabrication of nano-electronic devices. To avoid adsorption of salts and alkali ions, buffer solutions have been replaced by pure water or alkali-metal-ion-free buffer. However, proteins in such solutions are sometimes denatured. Therefore, we developed a substrate which adsorbs ferritin but does not adsorb contaminants such as salts and alkali metal-ions contained in the buffer. Adsorption of ferritin was achieved by using a buffer with a high ion strength, such as PBS buffer, because the Debye length becomes shorter with increased ion strength due to intermolecular force even when the substrate has no positive charge. The combination of high coverage methyltrimethoxysilane (MTMS)-coupled silicon substrate and PBS buffer solution is effective for adsorption of ferritin while not adsorbing buffer components such as contaminants and/or salts on the silicon substrate.

  1. Visualization of Buffer Capacity with 3-D "Topo" Surfaces: Buffer Ridges, Equivalence Point Canyons and Dilution Ramps

    ERIC Educational Resources Information Center

    Smith, Garon C.; Hossain, Md Mainul

    2016-01-01

    BufCap TOPOS is free software that generates 3-D topographical surfaces ("topos") for acid-base equilibrium studies. It portrays pH and buffer capacity behavior during titration and dilution procedures. Topo surfaces are created by plotting computed pH and buffer capacity values above a composition grid with volume of NaOH as the x axis…

  2. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals

    PubMed Central

    McMahon, Shane M.; Chang, Che-Wei

    2016-01-01

    Cytosolic Ca2+ buffers bind to a large fraction of Ca2+ as it enters a cell, shaping Ca2+ signals both spatially and temporally. In this way, cytosolic Ca2+ buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca2+ entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca2+ buffers in controlling pituitary Ca2+ signaling is poorly understood. Here, cytosolic Ca2+ buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca2+ indicator fluo-8 revealed stepwise increases in free Ca2+ after a series of brief depolarizing pulses in rapid succession. These Ca2+ increments grew larger as free Ca2+ rose to saturate the cytosolic buffers and reduce the availability of Ca2+ binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5–4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca2+ buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca2+ signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones. PMID:26880753

  3. Effect of IDA and TREN chelating agents and buffer systems on the purification of human IgG with immobilized nickel affinity membranes.

    PubMed

    Ribeiro, Mariana Borsoi; Vijayalakshmi, Mookambesvaran; Todorova-Balvay, Daniele; Bueno, Sonia Maria Alves

    2008-01-01

    The purification of IgG from human plasma was studied by comparing two affinity membranes complexed with Ni(II), prepared by coupling iminodiacetic acid (IDA) and Tris(2-aminoethyl)amine (TREN) to poly(ethylenevinyl alcohol), PEVA, hollow fiber membranes. The Ni(II)-TREN-PEVA hollow fiber membrane had lower capacity for human IgG than the complex Ni(II)-IDA-PEVA, but with similar selectivity. The IgG in peak fractions eluted from the Ni(II)-IDA-PEVA with a stepwise concentration gradient of Tris-HCl pH 7.0 (100-700 mM) reached a purity of 98% (based on IgG, IgM, IgA, albumin, and transferrin nephelometric analysis). Adsorption IgG data at different temperatures (4-37 degrees C) were analyzed using Langmuir model resulting in a calculated maximum capacity at 25 degrees C of 204.6 mg of IgG/g of dry membrane. Decrease in Kd with increasing temperature (1.7x10(-5) to 5.3x10(-6) M) indicated an increase in affinity with increased temperature. The positive value of enthalpy change (26.2 kJ/mol) indicated that the adsorption of IgG in affinity membrane is endothermic. Therefore, lower temperature induces adsorption as verified experimentally.

  4. Groundwater nitrate following installation of a vegetated riparian buffer.

    PubMed

    Yamada, Toshiro; Logsdon, Sally D; Tomer, Mark D; Burkart, Michael R

    2007-10-15

    Substantial questions remain about the time required for groundwater nitrate to be reduced below 10 mg L(-1) following establishment of vegetated riparian buffers. The objective of this study was to document changes in groundwater nitrate-nitrogen (NO3-N) concentrations that occurred within a few years of planting a riparian buffer. In 2000 and 2001 a buffer was planted adjacent to a first-order stream in the deep loess region of western Iowa with strips of walnut and cottonwood trees, alfalfa and brome grass, and switch grass. Non-parametric statistics showed significant declines in NO3-N concentrations in shallow groundwater following buffer establishment, especially mid 2003 and later. The dissolved oxygen generally was >5 mg L(-1) beneath the buffer, and neither NO3-N nor DO changed significantly under a non-buffered control area. These short-term changes in groundwater NO3-N provide evidence that vegetated riparian buffers may yield local water-quality benefits within a few years of planting.

  5. Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals.

    PubMed

    Rugbjerg, Peter; Genee, Hans Jasper; Jensen, Kristian; Sarup-Lytzen, Kira; Sommer, Morten Otto Alexander

    2016-07-15

    Predictable integration of foreign biological signals and parts remains a key challenge in the systematic engineering of synthetic cellular actuations, and general methods to improve signal transduction and sensitivity are needed. To address this problem we modeled and built a molecular signal buffer network in Saccharomyces cerevisiae inspired by chemical pH buffer systems. The molecular buffer system context-insulates a riboswitch enabling synthetic control of colony formation and modular signal manipulations. The riboswitch signal is relayed to a transcriptional activation domain of a split transcription factor, while interacting DNA-binding domains mediate the transduction of signal and form an interacting molecular buffer. The molecular buffer system enables modular signal inversion through integration with repressor modules. Further, tuning of input sensitivity was achieved through perturbation of the buffer pair ratio guided by a mathematical model. Such buffered signal tuning networks will be useful for domestication of RNA-based sensors enabling tunable outputs and library-wide selections for drug discovery and metabolic engineering.

  6. Improved ultrastructure of marine invertebrates using non-toxic buffers.

    PubMed

    Montanaro, Jacqueline; Gruber, Daniela; Leisch, Nikolaus

    2016-01-01

    Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates.

  7. Monitoring Liverworts to Evaluate the Effectiveness of Hydroriparian Buffers

    NASA Astrophysics Data System (ADS)

    Higgins, Kellina L.; Yasué, Maï

    2014-01-01

    In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas ( n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones ( n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25-35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.

  8. Gilliam County Riparian Buffers; 2003-2004 Annual Reports.

    SciTech Connect

    Coiner, Josh

    2004-06-01

    Interest appears to be at an all-time high for riparian conservation programs in Gilliam County. With the recently added Herbaceous Buffer and the already established CREP program interest is booming. However, more and more people are turning towards the herbaceous buffer because of expense. The riparian forest buffer is becoming too expensive. Even with the excellent cost share and incentives landowners are having trouble with Farm Service Agency's payment limitation. Because of this payment limitation landowners are not receiving their full rental and incentive payments, usually in year one. This has cooled the installation of riparian forest buffers and peaked interest in the CP-29 (Herbaceous Buffer for Wildlife). Either way, riparian lands are being enhanced and water quality is being improved. Year three should be very similar to the accomplishments of year 2. There has already been several projects proposed that may or may not be approved during year 3. I am currently working on three projects that are all over 2.5 miles long on each side and total anywhere from 60 to 250 acres in size. Along with these three projects there at least seven small projects being proposed. Four of those projects are riparian forest buffers and the remaining are herbaceous buffers.

  9. Buffer Gas Experiments in Mercury (Hg+) Ion Clock

    NASA Technical Reports Server (NTRS)

    Chung, Sang K.; Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2004-01-01

    We describe the results of the frequency shifts measured from various buffer gases that might be used as a buffer gas to increase the loading efficiency and cooling of ions trapped in a small mercury ion clock. The small mass, volume and power requirement of space clock precludes the use of turbo pumps. Hence, a hermetically sealed vacuum system, incorporating a suitable getter material with a fixed amount of inert buffer gas may be a practical alternative to the groundbased system. The collision shifts of 40,507,347.996xx Hz clock transition for helium, neon and argon buffer gases were measured in the ambient earth magnetic field. In addition to the above non-getterable inert gases we also measured the frequency shifts due to getterable, molecular hydrogen and nitrogen gases which may be used as buffer gases when incorporated with a miniature ion pump. We also examined the frequency shift due to the low methane gas partial pressure in a fixed higher pressure neon buffer gas environment. Methane gas interacted with mercury ions in a peculiar way as to preserve the ion number but to relax the population difference in the two hyperfine clock states and thereby reducing the clock resonance signal. The same population relaxation was also observed for other molecular buffer gases (N H,) but at much reduced rate.

  10. Improved ultrastructure of marine invertebrates using non-toxic buffers

    PubMed Central

    Montanaro, Jacqueline; Gruber, Daniela

    2016-01-01

    Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the mussel Mytilus edulis when fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates. PMID:27069800

  11. Monitoring liverworts to evaluate the effectiveness of hydroriparian buffers.

    PubMed

    Higgins, Kellina L; Yasué, Maï

    2014-01-01

    In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas (n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones (n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25-35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.

  12. A Tight Upper Bound on Online Buffer Management for Multi-Queue Switches with Bicodal Buffers

    NASA Astrophysics Data System (ADS)

    Kobayashi, Koji; Miyazaki, Shuichi; Okabe, Yasuo

    The online buffer management problem formulates the problem of queuing policies of network switches supporting QoS (Quality of Service) guarantee. In this paper, we consider one of the most standard models, called multi-queue switches model. In this model, Albers et al. gave a lower bound \\frac{e}{e-1}, and Azar et al. gave an upper bound \\frac{e}{e-1} on the competitive ratio when m, the number of input ports, is large. They are tight, but there still remains a gap for small m. In this paper, we consider the case where m = 2, namely, a switch is equipped with two ports, which is called a bicordal buffer model. We propose an online algorithm called Segmental Greedy Algorithm (SG) and show that its competitive ratio is at most \\frac{16}{13} (\\simeq 1.231), improving the previous upper bound by \\frac{9}{7} (\\simeq 1.286). This matches the lower bound given by Schmidt.

  13. Wasco Riparian Buffer Project, Annual Report 2003-2004.

    SciTech Connect

    Graves, Ron

    2003-07-01

    This project implements riparian buffer systems in the Mid-Columbia, addressing limiting factors identified in the Deschutes River Sub-basin Summary, March 2, 2001. This project is providing the technical planning support needed to implement at least 20 riparian buffer system contracts on approximately 800 acres covering an estimated 36 miles of anadromous fish streams. During this second year of implementation, 17 buffer contracts were established on 173,462 ft. of stream (25.9 miles). Acreage included in the buffers totaled 891.6 acres. Average buffer width was 112 ft. on each side of the stream. Cumulative totals through the first two project years are 26 buffers on 36.6 stream miles covering 1,283.6 acres. Actual implementation costs, lease payments, and maintenance costs will be borne by existing USDA programs: Conservation Reserve (CRP) and Conservation Reserve Enhancement Programs (CREP). The lease period of each contract may vary from 10 to 15 years. During this year, the average lease period was 14.9 years. The total value of contracts established this year is $1,421,268 compared with $55,504 in BPA contract costs to provide the technical support needed to get the contracts implemented. Cumulative contract value for the first two years is $1,919,451 compared to $103,329 cost to BPA. This project provides technical staffing to conduct assessments and develop conservation plans required for riparian buffer systems to help keep pace with a growing backlog of potential buffer projects. This project meets a critical need in the lower Deschutes and lower John Day River basins and complements the Riparian Buffer project approved for Fifteenmile watershed, Project No. 2001-021-00 begun in fiscal year 2001. This project supports RPA 150 and 153 as required under the Federal Hydropower System biological opinion and benefits the mid-Columbia ESU of steelhead.

  14. Buffer layers for REBCO films for use in superconducting devices

    DOEpatents

    Goyal, Amit; Wee, Sung-Hun

    2014-06-10

    A superconducting article includes a substrate having a biaxially textured surface. A biaxially textured buffer layer, which can be a cap layer, is supported by the substrate. The buffer layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different transition metal cations. A biaxially textured superconductor layer is deposited so as to be supported by the buffer layer. A method of making a superconducting article is also disclosed.

  15. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    DOEpatents

    Bajikar, Sateesh S.; De Carlo, Francesco; Song, Joshua J.

    2001-01-01

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized form pyromellitic anhydride and oxydianiline (PMDA-ODA).

  16. Enhanced adhesion for LIGA microfabrication by using a buffer layer

    DOEpatents

    Bajikar, Sateesh S.; De Carlo, Francesco; Song, Joshua J.

    2004-01-27

    The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer include polyamides and polyimide. The preferred polyimide is synthesized form pyromellitic anhydride and oxydianiline (PMDA-ODA).

  17. Investigation of active-buffer pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Zhu, Shaowei; Kakimi, Yasuhiro; Matsubara, Yoichi

    An active-buffer pulse tube refrigerator, which is a GM type pulse tube refrigerator, is described in this paper. Two or more buffers are connected at the hot end of the pulse tube through on/off valves. The main purpose of this method is to increase the efficiency. A numerical method is introduced to analyse the working process. To understand the basic mechanism, an ideal cycle is also introduced. With a prototype single stage active-buffer pulse tube refrigerator, a cooling capacity of 166 W and a percent Carnot of 13% at 80 K have been obtained.

  18. Evidence for positive mood buffering among college student drinkers.

    PubMed

    Mohr, Cynthia D; Brannan, Debi; Mohr, Josh; Armeli, Stephen; Tennen, Howard

    2008-09-01

    Positive experiences play an important role in buffering the effects of negative experiences. Although this process can play out in a myriad of contexts, the college context is one of particular importance because of significant concerns about student stress levels and alcohol abuse. Building on evidence that at least some students drink in response to negative experiences, we considered the possibility that positive moods would moderate college student negative mood-drinking relationships. Using a Web-based daily process study of 118 (57% women) undergraduate student drinkers, the authors reveal that positive moods indeed buffer the effects of negative moods on student drinking, depending on the mood and drinking context. Furthermore, the buffering of ashamed mood appears to explain the buffering of other negative moods. Implications of these findings are considered in terms of the relationship between negative self-awareness and drinking to cope.

  19. On buffer layers as non-reflecting computational boundaries

    NASA Technical Reports Server (NTRS)

    Hayder, M. Ehtesham; Turkel, Eli L.

    1996-01-01

    We examine an absorbing buffer layer technique for use as a non-reflecting boundary condition in the numerical simulation of flows. One such formulation was by Ta'asan and Nark for the linearized Euler equations. They modified the flow inside the buffer zone to artificially make it supersonic in the layer. We examine how this approach can be extended to the nonlinear Euler equations. We consider both a conservative and a non-conservative form modifying the governing equations in the buffer layer. We compare this with the case that the governing equations in the layer are the same as in the interior domain. We test the effectiveness of these buffer layers by a simulation of an excited axisymmetric jet based on a nonlinear compressible Navier-Stokes equations.

  20. Analysis of a unidirectional, symmetric buffer strip laminate with damage

    NASA Technical Reports Server (NTRS)

    Dharani, L. R.; Goree, J. G.

    1984-01-01

    A method for predicting the fracture behavior of hybrid buffer strip laminates is presented in which the classical shear-lag model is used to represent the shear stress distribution between adjacent fibers. The method is demonstrated by applying it to a notched graphite/epoxy laminate, and the results show clearly the manner in which the most efficient combination of buffer strip properties can be selected in order to arrest the crack. The ultimate failure stress of the laminate is plotted vs the buffer strip width. It is shown that in the case of graphite-epoxy and S-glass epoxy laminates, the optimum buffer strip spacing to width ratio should be about four to one.

  1. 4. EAST FACE. VEGETATIVE SCREENS BUFFER THE BUILDING FROM INDUSTRIAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. EAST FACE. VEGETATIVE SCREENS BUFFER THE BUILDING FROM INDUSTRIAL AREAS TO THE SOUTH OF OARB. - Oakland Army Base, General Purpose Administration Building, Chungking & Algiers Streets, Oakland, Alameda County, CA

  2. Optimizing the availability of a buffered industrial process

    DOEpatents

    Martz, Jr., Harry F.; Hamada, Michael S.; Koehler, Arthur J.; Berg, Eric C.

    2004-08-24

    A computer-implemented process determines optimum configuration parameters for a buffered industrial process. A population size is initialized by randomly selecting a first set of design and operation values associated with subsystems and buffers of the buffered industrial process to form a set of operating parameters for each member of the population. An availability discrete event simulation (ADES) is performed on each member of the population to determine the product-based availability of each member. A new population is formed having members with a second set of design and operation values related to the first set of design and operation values through a genetic algorithm and the product-based availability determined by the ADES. Subsequent population members are then determined by iterating the genetic algorithm with product-based availability determined by ADES to form improved design and operation values from which the configuration parameters are selected for the buffered industrial process.

  3. Buffer layers for high-Tc thin films on sapphire

    NASA Technical Reports Server (NTRS)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  4. RESEARCH SHOWS IMPORTANCE OF RIPARIAN BUFFERS FOR AQUATIC HEALTH

    EPA Science Inventory

    Issue: Excess nitrogen from fertilizer, septic tanks, animal feedlots, and runoff from pavement can threaten aquatic ecosystem health. Riparian buffers -- the vegetated region adjacent to streams and wetlands -- are thought to be effective at intercepting and controlling excess ...

  5. Prose recall and amnesia: more implications for the episodic buffer.

    PubMed

    Gooding, P A; Isaac, C L; Mayes, A R

    2005-01-01

    Baddeley and Wilson [Baddeley, A. D., & Wilson, F. B. (2002). Prose recall and amnesia: implications for the structure of working memory. Neuropsychologia 40, 1737-1743.] have argued that their finding of a positive association between amnesics' immediate prose recall scores and their scores on measures of executive function and fluid intelligence supports the view that an episodic buffer exists. However, the pattern of data from amnesics tested in our laboratory presented some problems for this conceptualisation of the episodic buffer.

  6. Carbon dioxide in the ocean surface: The homogeneous buffer factor

    USGS Publications Warehouse

    Sundquist, E.T.; Plummer, L.N.; Wigley, T.M.L.

    1979-01-01

    The amount of carbon dioxide that can be dissolved in surface seawater depends at least partially on the homogeneous buffer factor, which is a mathematical function of the chemical equilibrium conditions among the various dissolved inorganic species. Because these equilibria are well known, the homogeneous buffer factor is well known. Natural spatial variations depend very systematically on sea surface temperatures, and do not contribute significantly to uncertainties in the present or future carbon dioxide budget. Copyright ?? 1979 AAAS.

  7. Mechanisms of social buffering of fear in zebrafish

    PubMed Central

    Faustino, Ana I.; Tacão-Monteiro, André; Oliveira, Rui F.

    2017-01-01

    Some humans thrive whereas others resign when exposed to threatening situations throughout life. Social support has been identified as an important modulator of these discrepancies in human behaviour, and other social animals also exhibit phenomena in which individuals recover better from aversive events when conspecifics are present – aka social buffering. Here we studied social buffering in zebrafish, by exposing focal fish to an aversive stimulus (alarm substance – AS) either in the absence or presence of conspecific cues. When exposed to AS in the presence of both olfactory (shoal water) and visual (sight of shoal) conspecific cues, focal fish exhibited a lower fear response than when tested alone, demonstrating social buffering in zebrafish. When separately testing each cue’s effectiveness, we verified that the visual cue was more effective than the olfactory in reducing freezing in a persistent threat scenario. Finally, we verified that social buffering was independent of shoal size and coincided with a distinct pattern of co-activation of brain regions known to be involved in mammalian social buffering. Thus, this study suggests a shared evolutionary origin for social buffering in vertebrates, bringing new evidence on the behavioural, sensory and neural mechanisms underlying this phenomenon. PMID:28361887

  8. Good’s buffers as a basis for developing self-buffering and biocompatible ionic liquids for biological research†

    PubMed Central

    Taha, Mohamed; e Silva, Francisca A.; Quental, Maria V.; Ventura, Sónia P. M.; Freire, Mara G.; Coutinho, João A. P.

    2014-01-01

    This work reports a promising approach to the development of novel self-buffering and biocompatible ionic liquids for biological research in which the anions are derived from biological buffers (Good’s buffers, GB). Five Good’s buffers (Tricine, TES, CHES, HEPES, and MES) were neutralized with four suitable hydroxide bases (1-ethyl-3-methylimidazolium, tetramethylammonium, tetraethylammonium, and tetrabutylammonium) producing 20 Good’s buffer ionic liquids (GB-ILs). The presence of the buffering action of the synthesized GB-ILs was ascertained by measuring their pH-profiles in water. Moreover, a series of mixed GB-ILs with wide buffering ranges were formulated as universal buffers. The impact of GB-ILs on bovine serum albumin (BSA), here used as a model protein, is discussed and compared with more conventional ILs using spectroscopic techniques, such as infrared and dynamic light scattering. They appear to display, in general, a greater stabilizing effect on the protein secondary structure than conventional ILs. A molecular docking study was also carried out to investigate on the binding sites of GB-IL ions to BSA. We further used the QSAR-human serum albumin binding model, log K(HSA), to calculate the binding affinity of some conventional ILs/GB-ILs to HSA. The toxicity of the GB and GB-ILs was additionally evaluated revealing that they are non-toxic against Vitro fischeri. Finally, the GB-ILs were also shown to be able to form aqueous biphasic systems when combined with aqueous solutions of inorganic or organic salts, and we tested their extraction capability for BSA. These systems were able to extract BSA with an outstanding extraction efficiency of 100% in a single step for the GB-IL-rich phase, and, as a result, the use of GB-IL-based ABS for the separation and extraction of other added-value biomolecules is highly encouraging and worthy of further investigation. PMID:25729325

  9. Good's buffers as a basis for developing self-buffering and biocompatible ionic liquids for biological research.

    PubMed

    Taha, Mohamed; E Silva, Francisca A; Quental, Maria V; Ventura, Sónia P M; Freire, Mara G; Coutinho, João A P

    2014-06-01

    This work reports a promising approach to the development of novel self-buffering and biocompatible ionic liquids for biological research in which the anions are derived from biological buffers (Good's buffers, GB). Five Good's buffers (Tricine, TES, CHES, HEPES, and MES) were neutralized with four suitable hydroxide bases (1-ethyl-3-methylimidazolium, tetramethylammonium, tetraethylammonium, and tetrabutylammonium) producing 20 Good's buffer ionic liquids (GB-ILs). The presence of the buffering action of the synthesized GB-ILs was ascertained by measuring their pH-profiles in water. Moreover, a series of mixed GB-ILs with wide buffering ranges were formulated as universal buffers. The impact of GB-ILs on bovine serum albumin (BSA), here used as a model protein, is discussed and compared with more conventional ILs using spectroscopic techniques, such as infrared and dynamic light scattering. They appear to display, in general, a greater stabilizing effect on the protein secondary structure than conventional ILs. A molecular docking study was also carried out to investigate on the binding sites of GB-IL ions to BSA. We further used the QSAR-human serum albumin binding model, log K(HSA), to calculate the binding affinity of some conventional ILs/GB-ILs to HSA. The toxicity of the GB and GB-ILs was additionally evaluated revealing that they are non-toxic against Vitro fischeri. Finally, the GB-ILs were also shown to be able to form aqueous biphasic systems when combined with aqueous solutions of inorganic or organic salts, and we tested their extraction capability for BSA. These systems were able to extract BSA with an outstanding extraction efficiency of 100% in a single step for the GB-IL-rich phase, and, as a result, the use of GB-IL-based ABS for the separation and extraction of other added-value biomolecules is highly encouraging and worthy of further investigation.

  10. Intrinsic cytosolic calcium buffering properties of single rat cardiac myocytes.

    PubMed Central

    Berlin, J R; Bassani, J W; Bers, D M

    1994-01-01

    Intracellular passive Ca2+, buffering was measured in voltage-clamped rat ventricular myocytes. Cells were loaded with indo-1 (K+ salt) to an estimated cytosolic concentration of 44 +/- 5 microM (Mean +/- SEM, n = 5), and accessible cell volume was estimated to be 24.5 +/- 3.6 pl. Ca2+ transport by the sarcoplasmic reticulum (SR) Ca-ATPase and sarcolemmal Na-Ca exchange was inhibited by treatment with thapsigargin and Na-free solutions, respectively. Extracellular [Ca2+] was maintained at 10 mM and, in some experiments, the mitochondrial uncoupler "1799" was used to assess the degree of mitochondrial Ca2+ uptake. To perform single cell titrations, intracellular Ca2+ ([Ca2+]i) was increased progressively by a train of depolarizing voltage clamp pulses from -40 to +10 mV. The total Ca2+ gain with each pulse was calculated by integration of the Ca current and then analyzed as a function of the rapid change in [Ca2+]i during the pulse. In the range of [Ca2+]i from 0.1 to 2 microM, overall cell buffering was well described as a single lumped Michaelis-Menten type species with an apparent dissociation constant, KD, of of 0.63 +/- 0.07 microM (n = 5) and a binding capacity, Bmax, of 162 +/- 15 mumol/l cell H2O. Correction for buffering attributable to cytosolic indo-1 gives intrinsic cytosolic Ca2+ buffering parameters of KD = 0.96 +/- 0.18 microM and Bmax = 123 +/- 18 mumol/l cell H2O. The fast Ca2+ buffering measured in this manner agrees reasonably with the characteristics of known rapid Ca buffers (e.g., troponin C, calmodulin, and SR Ca-ATPase), but is only about half of the total Ca2+ buffering measured at equilibrium. Inclusion of slow Ca buffers such as the Ca/Mg sites on troponin C and myosin can account for the differences between fast Ca2+ buffering in phase with the Ca current measured in the present experiments and equilibrium Ca2+ buffering. The present data indicate that a rapid rise of [Ca2+]i from 0.1 to 1 microM during a contraction requires

  11. Lagenin, a novel ribosome-inactivating protein with ribonucleolytic activity from bottle gourd (Lagenaria siceraria) seeds.

    PubMed

    Wang, H X; Ng, T B

    2000-10-13

    The seeds of Lagenaria siceraria (Family Cucurbitaceae) were extracted with water and the extract was lyophilized. The lyophilized extract was chromatographed on a DEAE-cellulose column in 10 mM Tris-HCl buffer (pH 7.2). The unadsorbed fraction was applied to an Affi-gel Blue gel column previously equilibrated with the same buffer. After removal of unadsorbed materials, the adsorbed proteins were eluted with 1.5 M NaCl in the Tris-HCl buffer. After dialysis the adsorbed fraction was loaded on a CM-Sepharose CL-6B column which had been equilibrated with and was eluted with the same buffer. After elution of unadsorbed proteins, the column was eluted with a gradient of 0-1 M NaCl in 10 mM Tris-HCl buffer (pH 7.2). The fraction eluting at about 0.55 M NaCl, which represented pure ribosome inactivating protein (RIP), inhibited cell-free translation in a rabbit reticulocyte system with an IC50 of 0.21 nM and exerted ribonuclease activity on yeast tRNA with an activity of 45 U/mg. The RIP was designated lagenin. It possessed a molecular weight of 20 kDa, smaller than the range of 26-32 kDa reported for other RIPs. The N-terminal sequence of lagenin exhibited a lesser extent of similarity to those of other Cucurbitaceae RIPs, characterized by a deletion of the first three amino acid residues and a replacement of the 4th (Phe), 17th (Phe), 18th (Ile) and 22nd (Arg) residues which are invariant in other RIPs.

  12. Assessing multiregion avian benefits from strategically targeted agricultural buffers.

    PubMed

    Evans, Kristine O; Burger, L Wes; Riffell, Sam; Smith, Mark D

    2014-08-01

    Mounting evidence of wildlife population gains from targeted conservation practices has prompted the need to develop and evaluate practices that are integrated into production agriculture systems and targeted toward specific habitat objectives. However, effectiveness of targeted conservation actions across broader landscapes is poorly understood. We evaluated multiregion, multispecies avian densities on row-crop fields with native grass field margins (i.e., buffers) as part of the first U.S. agricultural conservation practice designed to support habitat and population recovery objectives of a national wildlife conservation initiative. We coordinated breeding season point transect surveys for 6 grassland bird species on 1151 row-crop fields with and without native grass buffers (9-37 m) in 14 U.S. states (10 ecoregions) from 2006 to 2011. In most regions, breeding season densities of 5 of 6 targeted bird species were greater in the 500-m surrounding survey points centered on fields with native grass buffers than in landscapes without buffers. Relative effect sizes were greatest for Northern Bobwhite (Colinus virginianus), Dickcissel (Spiza americana), and Field Sparrow (Spizella pusilla) in the Mississippi Alluvial Valley and Eastern Tallgrass Prairie regions. Other species (e.g., Eastern Meadowlark [Sturnella magna], Grasshopper Sparrow [Ammodramus savannarum]) exhibited inconsistent relative effect sizes. Bird densities on fields with and without buffers were greatest in the Central Mixed-grass Prairie region. Our results suggest that strategic use of conservation buffers in regions with the greatest potential for relative density increases in target species will elicit greater range-wide population response than diffuse, uninformed, and broadly distributed implementation of buffers. We recommend integrating multiple conservation practices in broader agricultural landscapes to maximize conservation effectiveness for a larger suite of species.

  13. Mapping Soil pH Buffering Capacity of Selected Fields

    NASA Technical Reports Server (NTRS)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

  14. CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS

    SciTech Connect

    Paranthaman, Mariappan Parans

    2011-01-01

    We have reviewed briefly the growth of buffer and high temperature superconducting oxide thin films using a chemical solution deposition (CSD) method. In the Rolling-Assisted Biaxially Textured Substrates (RABiTS) process, developed at Oak Ridge National Laboratory, utilizes the thermo mechanical processing to obtain the flexible, biaxially oriented copper, nickel or nickel-alloy substrates. Buffers and Rare Earth Barium Copper Oxide (REBCO) superconductors have been deposited epitaxially on the textured nickel alloy substrates. The starting substrate serves as a template for the REBCO layer, which has substantially fewer weak links. Buffer layers play a major role in fabricating the second generation REBCO wire technology. The main purpose of the buffer layers is to provide a smooth, continuous and chemically inert surface for the growth of the REBCO film, while transferring the texture from the substrate to the superconductor layer. To achieve this, the buffer layers need to be epitaxial to the substrate, i.e. they have to nucleate and grow in the same bi-axial texture provided by the textured metal foil. The most commonly used RABiTS multi-layer architectures consist of a starting template of biaxially textured Ni-5 at.% W (Ni-W) substrate with a seed (first) layer of Yttrium Oxide (Y2O3), a barrier (second) layer of Yttria Stabilized Zirconia (YSZ), and a Cerium Oxide (CeO2) cap (third) layer. These three buffer layers are generally deposited using physical vapor deposition (PVD) techniques such as reactive sputtering. On top of the PVD template, REBCO film is then grown by a chemical solution deposition. This article reviews in detail about the list of oxide buffers and superconductor REBCO films grown epitaxially on single crystal and/or biaxially textured Ni-W substrates using a CSD method.

  15. Message communications of particular message types between compute nodes using DMA shadow buffers

    DOEpatents

    Blocksome, Michael A.; Parker, Jeffrey J.

    2010-11-16

    Message communications of particular message types between compute nodes using DMA shadow buffers includes: receiving a buffer identifier specifying an application buffer having a message of a particular type for transmission to a target compute node through a network; selecting one of a plurality of shadow buffers for a DMA engine on the compute node for storing the message, each shadow buffer corresponding to a slot of an injection FIFO buffer maintained by the DMA engine; storing the message in the selected shadow buffer; creating a data descriptor for the message stored in the selected shadow buffer; injecting the data descriptor into the slot of the injection FIFO buffer corresponding to the selected shadow buffer; selecting the data descriptor from the injection FIFO buffer; and transmitting the message specified by the selected data descriptor through the data communications network to the target compute node.

  16. Social buffering of the stress response: diversity, mechanisms, and functions.

    PubMed

    Hennessy, Michael B; Kaiser, Sylvia; Sachser, Norbert

    2009-10-01

    Protracted or repeated activation of the hypothalamic-pituitary-adrenocortical (HPA) system is associated with a variety of physical and psychological pathologies. Studies dating back to the 1970s have documented many cases in which the presence of a social companion can moderate HPA responses to stressors. However, there also are many cases in which this "social buffering" of the HPA axis is not observed. An examination of the literature indicates that the nature of the relationship between individuals is crucial in determining whether or not social buffering of the HPA response will occur. Other factors that affect social buffering, either directly or by influencing the social relationship, include the social organization of the species, previous experience, gender, integration into a social unit, and the developmental stage at which individuals are examined. Current evidence suggests that social buffering involves mechanisms acting at more than one level of the CNS. It is suggested that, in addition to promoting health, social buffering may have evolved to direct the establishment of social relationships, and to facilitate developmental transitions in social interactions appropriate for different life stages.

  17. RNA chaperones buffer deleterious mutations in E. coli

    PubMed Central

    Rudan, Marina; Schneider, Dominique; Warnecke, Tobias; Krisko, Anita

    2015-01-01

    Both proteins and RNAs can misfold into non-functional conformations. Protein chaperones promote native folding of nascent polypeptides and refolding of misfolded species, thereby buffering mutations that compromise protein structure and function. Here, we show that RNA chaperones can also act as mutation buffers that enhance organismal fitness. Using competition assays, we demonstrate that overexpression of select RNA chaperones, including three DEAD box RNA helicases (DBRHs) (CsdA, SrmB, RhlB) and the cold shock protein CspA, improves fitness of two independently evolved Escherichia coli mutator strains that have accumulated deleterious mutations during short- and long-term laboratory evolution. We identify strain-specific mutations that are deleterious and subject to buffering when introduced individually into the ancestral genotype. For DBRHs, we show that buffering requires helicase activity, implicating RNA structural remodelling in the buffering process. Our results suggest that RNA chaperones might play a fundamental role in RNA evolution and evolvability. DOI: http://dx.doi.org/10.7554/eLife.04745.001 PMID:25806682

  18. Effect of various commercial buffers on sperm viability and capacitation.

    PubMed

    Andrisani, Alessandra; Donà, Gabriella; Ambrosini, Guido; Bonanni, Guglielmo; Bragadin, Marcantonio; Cosmi, Erich; Clari, Giulio; Armanini, Decio; Bordin, Luciana

    2014-08-01

    A wide variety of sperm preparation protocols are currently available for assisted conception. They include density gradient separation and washing methods. Both aim at isolating and capacitating as much motile sperm as possible for subsequent oocyte fertilization. The aim of this study was to examine the effects of four commercial sperm washing buffers on sperm viability and capacitation. Semen samples from 48 healthy donors (normal values of sperm count, motility, morphology, and volume) were analyzed. After separation (density gradient 40/80%), sperm were incubated in various buffers then analysed for reactive oxygen species (ROS) production, viability, tyrosine phosphorylation (Tyr-P), cholera toxin B subunit (CTB) labeling, and the acrosome reaction (AR). The buffers affected ROS generation in various ways resulting either in rapid cell degeneration (when the amount of ROS was too high for cell survival) or the inability of the cells to maintain correct functioning (when ROS were too few). Only when the correct ROS generation curve was maintained, suitable membrane reorganization, evidenced by CTB labeling was achieved, leading to the highest percentages of both Tyr-P- and acrosome-reacted-cells. Distinguishing each particular pathological state of the sperm sample would be helpful to select the preferred buffer treatment since both ROS production and membrane reorganization can be significantly altered by commercial buffers.

  19. Integrated optical buffers for packet-switched networks

    NASA Astrophysics Data System (ADS)

    Burmeister, Emily Frances

    Routers form the backbone of the Internet, directing data to the right locations with huge throughput capacity of terabits/second) and very few errors (1 error allowed in 1012 bits). However, as the Internet continues to grow rapidly, so must the capacity of electronic routers, thereby also growing in footprint and power consumption. The energy bill alone has developers looking for an alternate solution. Today's routers can only operate with electrical signals although Internet data is transmitted optically. This requires the data to be converted from the optical domain to the electrical domain and back again. Optical routers have the potential of saving in power by omitting these conversions, but have been held back in part by the lack of a practical optical memory device. This work presents the first integrated optical buffer for next generation optical packet-switched networks. Buffering is required in a router to move packets of data in order to avoid collisions between packets heading to the same destination at the same time. The device presented here uses an InP-based two-by-two switch with a silica waveguide delay to form a recirculating buffer. Packet storage was shown with 98% packet recovery for 5 circulations. Autonomous contention resolution was demonstrated with two buffered channels to show that the technology is a realistic solution for creating multiple element buffers on multiple router ports. This thesis proposes and demonstrates the first integrated optical random access memory, thereby making a great stride toward high capacity optical routers.

  20. Grass buffers for playas in agricultural landscapes: An annotated bibliography

    USGS Publications Warehouse

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    References on best management practices (BMPs) for agricultural lands were included because certain BMPs are crucial for informing decisions about buffer design/ effectiveness and overall playa ecology. We also included various papers that increase the spectrum of time over which buffer theories and practices have evolved. An unannotated section lists references that we did not prioritize for annotation and references that may be helpful but were beyond the scope of this document. Finally, we provide notes on conversations we had with scientists, land managers, and other buffer experts whom we consulted, and their contact information. We conclude the bibliography with appendices of common and scientific names of birds and plants and acronyms used in both the bibliography. In the annotations, italicized text signifies our own editorial remarks. Readers should also note that much of the work on buffers has been designed using English units of measure rather than metrics; in most cases, their results have been converted to metrics for publication, explaining the seemingly odd or irregular buffer widths and other parameters reported.

  1. Rare earth zirconium oxide buffer layers on metal substrates

    DOEpatents

    Williams, Robert K.; Paranthaman, Mariappan; Chirayil, Thomas G.; Lee, Dominic F.; Goyal, Amit; Feenstra, Roeland

    2001-01-01

    A laminate article comprises a substrate and a biaxially textured (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer over the substrate, wherein 0buffer layer can be deposited using sol-gel or metal-organic decomposition. The laminate article can include a layer of YBCO over the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer. A layer of CeO.sub.2 between the YBCO layer and the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer can also be include. Further included can be a layer of YSZ between the CeO.sub.2 layer and the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer. The substrate can be a biaxially textured metal, such as nickel. A method of forming the laminate article is also disclosed.

  2. Method of depositing buffer layers on biaxially textured metal substrates

    DOEpatents

    Beach, David B.; Morrell, Jonathan S.; Paranthaman, Mariappan; Chirayil, Thomas; Specht, Eliot D.; Goyal, Amit

    2002-08-27

    A laminate article comprises a substrate and a biaxially textured (RE.sup.1.sub.x RE.sup.2.sub.(1-x)).sub.2 O.sub.3 buffer layer over the substrate, wherein 0buffer layer can be deposited using sol-gel or metal-organic decomposition. The laminate article can include a layer of YBCO over the (RE.sup.1.sub.x RE.sup.2.sub.(1-x)).sub.2 O.sub.3 buffer layer. A layer of CeO.sub.2 between the YBCO layer and the (RE.sup.1.sub.x RE.sup.2.sub.(1-x)).sub.2 O.sub.3 buffer can also be include. Further included can be a layer of YSZ between the CeO.sub.2 layer and the (RE.sup.1.sub.x RE.sup.2.sub.(1-x)).sub.2 O.sub.3 buffer layer. The substrate can be a biaxially textured metal, such as nickel. A method of forming the laminate article is also disclosed.

  3. Electrodialytic membrane suppressors for ion chromatography make programmable buffer generators.

    PubMed

    Chen, Yongjing; Srinivasan, Kannan; Dasgupta, Purnendu K

    2012-01-03

    The use of buffer solutions is immensely important in a great variety of disciplines. The generation of continuous pH gradients in flow systems plays an important role in the chromatographic separation of proteins, high-throughput pK(a) determinations, etc. We demonstrate here that electrodialytic membrane suppressors used in ion chromatography can be used to generate buffers. The generated pH, computed from first principles, agrees well with measured values. We demonstrate the generation of phosphate and citrate buffers using a cation-exchange membrane (CEM) -based anion suppressor and Tris and ethylenediamine buffers using an anion-exchange membrane (AEM) -based cation suppressor. Using a mixture of phosphate, citrate, and borate as the buffering ions and using a CEM suppressor, we demonstrate the generation of a highly reproducible (avg RSD 0.20%, n = 3), temporally linear (pH 3.0-11.9, r(2) > 0.9996), electrically controlled pH gradient. With butylamine and a large concentration (0.5 M) of added NaCl, we demonstrate a similar linear pH gradient of large range with a near-constant ionic strength. We believe that this approach will be of value for the generation of eluents in the separation of proteins and other biomolecules and in online process titrations.

  4. Nitrification utilizing CaCO3 as the buffering agent.

    PubMed

    Green, M; Ruskol, Y; Tarre, S; Loewenthal, R E

    2002-03-01

    Nitrification utilizing chalk (calcium carbonate) as the buffering agent was investigated. Three different fluidized bed reactor configurations were examined in order to study the effect of reactor layout on nitrification and concomitant chalk dissolution. The first system consisted of two interconnected columns with high recycle rate, one containing zeolite as the carrier for the nitrifying biomass and the other chalk as the buffering agent. The second reactor system consisted of a single column containing both zeolite and chalk particles. In the third system, nitrification was carried out in a single column where chalk particles were used both as the carrier for the biomass and as the buffer. Results showed that only the reactor with chalk acting as both the buffering agent and the biomass carrier could be operated without external buffer (NaHCO3) addition. This system operated at high ammonium removal rates of up to 2.5 g N l(-1) reactor d(-1) even though the bulk solution of the reactor had a low pH of 5.5. The high nitrification efficiency at this low pH was probably mainly a result of a favorable microenvironment surrounding the nitrifying biomass attached to the chalk.

  5. Buffer layers on metal alloy substrates for superconducting tapes

    DOEpatents

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-10-05

    An article including a substrate, at least one intermediate layer upon the surface of the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the at least one intermediate layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected I.sub.c 's of over 200 Amperes across a sample 1 cm wide.

  6. Buffer thermal energy storage for an air Brayton solar engine

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    The application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine was studied. To demonstrate the effect of buffer thermal energy storage on engine operation, a computer program was written which models the recuperator, receiver, and thermal storage device as finite-element thermal masses. Actual operating or predicted performance data are used for all components, including the rotating equipment. Based on insolation input and a specified control scheme, the program predicts the Brayton engine operation, including flows, temperatures, and pressures for the various components, along with the engine output power. An economic parametric study indicates that the economic viability of buffer thermal energy storage is largely a function of the achievable engine life.

  7. A 20 MHz CMOS reorder buffer for a superscalar microprocessor

    NASA Technical Reports Server (NTRS)

    Lenell, John; Wallace, Steve; Bagherzadeh, Nader

    1992-01-01

    Superscalar processors can achieve increased performance by issuing instructions out-of-order from the original sequential instruction stream. Implementing an out-of-order instruction issue policy requires a hardware mechanism to prevent incorrectly executed instructions from updating register values. A reorder buffer can be used to allow a superscalar processor to issue instructions out-of-order and maintain program correctness. This paper describes the design and implementation of a 20MHz CMOS reorder buffer for superscalar processors. The reorder buffer is designed to accept and retire two instructions per cycle. A full-custom layout in 1.2 micron has been implemented, measuring 1.1058 mm by 1.3542 mm.

  8. Optimization of buffer gas pressure for Rb atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Chen, Chang; Liu, Xiaohu; Qu, Tianliang; Yang, Kaiyong

    2015-08-01

    The optimization of buffer gas pressure is very important to improve the performance of the rubidium (Rb) atomic magnetometer. In this paper we briefly introduce the basic principle and the experimental method of the rubidium magnetometer based on Faraday rotation effect, and describe the factors affecting the magnetometer sensitivity, then analyze and summarize the mechanism of the influence of spin-exchange, spin-destruction collisions, radiation trapping and the spin diffusion on spin relaxation of Rb atoms. Based on this, the relationship between the rubidium magnetometer sensitivity, the spin relaxation rate and the gas chamber conditions (buffer gas pressure, the bubble radius, measuring temperature) is established. Doing calculations by the simulation software, how the magnetometer sensitivity and the relaxation rate vary with the gas chamber conditions can be seen; finally, the optimal values of the buffer gas pressure under certain gas chamber conditions are obtained. The work is significant for the engineering development of rubidium magnetometer.

  9. Use of buffered hypochlorite solution for disinfecting fibrescopes.

    PubMed

    Coates, D; Death, J E

    1982-03-01

    The possible use of sodium hypochlorite solution buffered to pH 7.6 and containing 100 ppm available chlorine (avCl) for disinfecting fibrescopes was investigated. A flexible fibrescope experimentally contaminated with Pseudomonas putida, Mycobacterium fortuitum, or Bacillus subtilis spores was effectively disinfected within 10 m in repeatedly and without any observable adverse effect on the instrument. The corrosive nature of buffered hypochlorite was investigated by immersing various fibrescope components and metal wires in solutions of different strength for long periods and examining them for damage. Stainless steel, platinum, glass, Teflon, polythene and epoxy resin were apparently unaffected whereas polyurethane, rubber and other metals tested were damaged to different extents. Buffered hypochlorite solutions may have many applications pertaining to the disinfection of items which are either thermolabile or require rapid effective disinfection.

  10. Quantifying the capacity of compost buffers for treating agricultural runoff

    NASA Astrophysics Data System (ADS)

    Naranjo, S. A.; Beighley, R. E.; Buyuksonmez, F.

    2007-12-01

    Agricultural operations, specifically, avocado and commercial nurseries require frequent and significant fertilizing and irrigating which tends to result in excessive nutrient leaching and off-site runoff. The increased runoff contains high concentrations of nutrients which negatively impacts stream water quality. Researcher has demonstrated that best management practices such as compost buffers can be effective for reducing nutrient and sediment concentrations in agricultural runoff. The objective of this research is to evaluate both the hydraulic capacity and the nutrient removal efficiency of: (a) compost buffers and (b) buffers utilizing a combination of vegetation and compost. A series of experiments will be performed in the environmental hydraulics laboratory at San Diego State University. A tilting flume 12-m long, 27-cm wide and 25-cm deep will be used. Discharge is propelled by an axial flow pump powered by a variable speed motor with a maximum capacity of 30 liters per second. The experiments are designed to measure the ratio compost mass per flow rate per linear width. Two different discharges will be measured: (a) treatment discharge (maximum flow rate such that the buffer decreases the incoming nitrogen and phosphorus concentrations below a maximum allowable limit) and (b) breaking discharge (maximum flow rate the buffer can tolerate without structural failure). Experimental results are presented for the hydraulic analysis, and preliminary results are presented for the removal of nitrogen and phosphorus from runoff. The results from this project will be used to develop guidelines for installing compost buffers along the perimeters of nursery sites and avocado groves in southern California.

  11. Agroforestry buffers for nonpoint source pollution reductions from agricultural watersheds.

    PubMed

    Udawatta, Ranjith P; Garrett, Harold E; Kallenbach, Robert

    2011-01-01

    Despite increased attention and demand for the adoption of agroforestry practices throughout the world, rigorous long-term scientific studies confirming environmental benefits from the use of agroforestry practices are limited. The objective was to examine nonpoint-source pollution (NPSP) reduction as influenced by agroforestry buffers in watersheds under grazing and row crop management. The grazing study consists of six watersheds in the Central Mississippi Valley wooded slopes and the row crop study site consists of three watersheds in a paired watershed design in Central Claypan areas. Runoff water samples were analyzed for sediment, total nitrogen (TN), and total phosphorus (TP) for the 2004 to 2008 period. Results indicate that agroforestry and grass buffers on grazed and row crop management sites significantly reduce runoff, sediment, TN, and TP losses to streams. Buffers in association with grazing and row crop management reduced runoff by 49 and 19%, respectively, during the study period as compared with respective control treatments. Average sediment loss for grazing and row crop management systems was 13.8 and 17.9 kg ha yr, respectively. On average, grass and agroforestry buffers reduced sediment, TN, and TP losses by 32, 42, and 46% compared with the control treatments. Buffers were more effective in the grazing management practice than row crop management practice. These differences could in part be attributed to the differences in soils, management, and landscape features. Results from this study strongly indicate that agroforestry and grass buffers can be designed to improve water quality while minimizing the amount of land taken out of production.

  12. Fifteenmile Creek Riparian Buffers Project, Annual Report 2002-2003.

    SciTech Connect

    Graves, Ron

    2004-02-01

    This project implements riparian buffer systems in the Mid-Columbia, addressing limiting factors identified in the Fifteenmile Subbasin Summary, June 30, 2000. The project is providing the technical planning support needed to implement at least 36 riparian buffer system contracts on approximately 872 acres covering an estimated 40 miles of anadromous fish streams over a three year period. During this second year of the project, 11 buffer contracts were implemented on 10.9 miles of stream. Buffer widths averaged 132 ft. on each side of the stream. Implementation included prescribed plantings, fencing, and related practices. Actual implementation costs, lease payments, and maintenance costs are borne by existing USDA programs: Conservation Reserve and Conservation Reserve Enhancement Programs. The lease period of each contract may vary between 10 to 15 years. During this year the average was 14.6 years. The total value of contracts established this year is $666,121 compared with $71,115 in Bonneville Power Administration (BPA) contract costs to provide the technical support needed to get the contracts implemented. This project provides technical staffing to conduct assessments and develop plans to help keep pace with the growing backlog of potential riparian buffer projects. Word of mouth from satisfied customers has brought in many new sign-ups during the year. In addition, specific outreach efforts targeting the orchard areas of the county began to bear fruit with orchardists sign-ups as the project year ended. Progress this second year of project includes only work accomplished in the Fifteenmile subbasin. A similar but separate effort to implement buffers in the Columbia Plateau Province was initiated during the year under project number 2002-019-00. This project supports RPA 150 and 153 as required under the Federal Hydropower System biological opinion.

  13. Buffer capacity of the coelomic fluid in echinoderms.

    PubMed

    Collard, Marie; Laitat, Kim; Moulin, Laure; Catarino, Ana I; Grosjean, Philippe; Dubois, Philippe

    2013-09-01

    The increase in atmospheric CO2 due to anthropogenic activity results in an acidification of the surface waters of the oceans. The impact of these chemical changes depends on the considered organisms. In particular, it depends on the ability of the organism to control the pH of its inner fluids. Among echinoderms, this ability seems to differ significantly according to species or taxa. In the present paper, we investigated the buffer capacity of the coelomic fluid in different echinoderm taxa as well as factors modifying this capacity. Euechinoidea (sea urchins except Cidaroidea) present a very high buffer capacity of the coelomic fluid (from 0.8 to 1.8mmolkg(-1) SW above that of seawater), while Cidaroidea (other sea urchins), starfish and holothurians have a significantly lower one (from -0.1 to 0.4mmolkg(-1) SW compared to seawater). We hypothesize that this is linked to the more efficient gas exchange structures present in the three last taxa, whereas Euechinoidea evolved specific buffer systems to compensate lower gas exchange abilities. The constituents of the buffer capacity and the factors influencing it were investigated in the sea urchin Paracentrotus lividus and the starfish Asterias rubens. Buffer capacity is primarily due to the bicarbonate buffer system of seawater (representing about 63% for sea urchins and 92% for starfish). It is also partly due to coelomocytes present in the coelomic fluid (around 8% for both) and, in P. lividus only, a compound of an apparent size larger than 3kDa is involved (about 15%). Feeding increased the buffer capacity in P. lividus (to a difference with seawater of about 2.3mmolkg(-1) SW compared to unfed ones who showed a difference of about 0.5mmolkg(-1) SW) but not in A. rubens (difference with seawater of about 0.2 for both conditions). In P. lividus, decreased seawater pH induced an increase of the buffer capacity of individuals maintained at pH7.7 to about twice that of the control individuals and, for those at pH7

  14. Calcium waves with fast buffers and mechanical effects.

    PubMed

    Kaźmierczak, Bogdan; Peradzyński, Zbigniew

    2011-01-01

    In the paper we consider the existence of calcium travelling waves for systems with fast buffers. We prove the convergence of the travelling waves to an asymptotic limit as the kinetic coefficients characterizing the interaction between calcium and buffers tend to infinity. To be more precise, we prove the convergence of the speeds as well as the calcium component concentration profile to the profile of the travelling wave of the reduced equation. Additionally, we take into account the effect of coupling between the mechanical and chemical processes and show the existence as well the monotonicity of the profiles of concentrations. This property guarantees their positivity.

  15. Impact of Burst Buffer Architectures on Application Portability

    SciTech Connect

    Harms, Kevin; Oral, H. Sarp; Atchley, Scott; Vazhkudai, Sudharshan S.

    2016-09-30

    The Oak Ridge and Argonne Leadership Computing Facilities are both receiving new systems under the Collaboration of Oak Ridge, Argonne, and Livermore (CORAL) program. Because they are both part of the INCITE program, applications need to be portable between these two facilities. However, the Summit and Aurora systems will be vastly different architectures, including their I/O subsystems. While both systems will have POSIX-compliant parallel file systems, their Burst Buffer technologies will be different. This difference may pose challenges to application portability between facilities. Application developers need to pay attention to specific burst buffer implementations to maximize code portability.

  16. Buffering capacity and membrane H+ conductance of Halobacterium halobium.

    PubMed

    Rius, N; Lorén, J G

    1996-09-01

    Buffering capacity and membrane H+ conductance were measured in Halobacterium halobium suspensions in the light and in the dark over a wide range of external pH. The values of both variables for this archaeobacterium were significantly higher than those found for eubacteria in other reports. It appears from our results that the special chemical composition of the cell envelope and the movement of ions, mainly protons, may influence the magnitude of the buffering power and the H+ membrane conductance of these cells.

  17. Optimizing Giant Unilamellar Vesicle Growth in a Physiological Buffer

    NASA Astrophysics Data System (ADS)

    Lambright, Geoffrey; Huang, Juyang

    2002-10-01

    Liposomes of 40 to 70 microns in diameter are good model systems for microscopy study of biomembrane heterogeneity. They also have a potential to be incorporated into biosensors. We search for the optimum condition to produce large numbers of giant unilamellar vesicles (GUV) in a physiological buffer. A thin lipid film is first dried on a test tube, and then slowly hydrated by water vapor before a buffer solution is added. We found that the yield of GUVs can be significantly influenced by the surface characteristics of the test tubes. By selecting the material of test tubes and optimizing other experimental conditions, we have increased the GUV yield more than ten fold.

  18. Influence of glyphosate on the copper dissolution in phosphate buffer

    NASA Astrophysics Data System (ADS)

    Coutinho, C. F. B.; Silva, M. O.; Machado, S. A. S.; Mazo, L. H.

    2007-01-01

    The electrochemical behavior of copper microelectrode in phosphate buffer in the presence of glyphosate was investigated by electrochemical techniques. It was observed that the additions of glyphosate in the phosphate buffer increased the anodic current of copper microelectrode and the electrochemical dissolution was observed. This phenomenon could be associated with the Cu(II) complexation by glyphosate forming a soluble complex. Physical characterization of the surface showed that, in absence of glyphosate, an insoluble layer covered the copper surface; on the other hand, in presence of glyphosate, it was observed a corroded copper surface with the formation of glyphosate complex in solution.

  19. A simple and effective SuperBuffer for DNA agarose electrophoresis.

    PubMed

    Zhang, Jun-He; Wang, Fang; Wang, Tian-Yun

    2011-11-01

    In the paper, we describe a unique effective electrophoresis buffer for DNA agarose electrophoresis, called SuperBuffer. Using this buffer, electrophoresis could be performed within 10 min at voltages as high as 25V/cm. In addition, DNA fragments of different lengths could be isolated clearly even at lower agarose gel concentrations and the DNA recovery efficiency was higher than that of the TAE/TBE running buffers. The SuperBuffer still retained its electrophoretic effect even after several uses.

  20. Woven graphite epoxy composite test specimens with glass buffer strips

    NASA Technical Reports Server (NTRS)

    Bonnar, G. R.; Palmer, R. J.

    1982-01-01

    Woven unidirectional graphite cloth with bands of fiberglass replacing the graphite in discrete lengthwise locations was impregnated with epoxy resin and used to fabricate a series of composite tensile and shear specimens. The finished panels, with the fiberglass buffer strips, were tested. Details of the fabrication process are reported.

  1. Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

    PubMed Central

    Puglis, Holly J.; Boone, Michelle D.

    2012-01-01

    A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians. PMID:22761833

  2. Diazinon and permethrin mitigation across a grass-wetland buffer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various management practices have been proposed to help alleviate deleterious effects of pesticides associated with agricultural runoff. Vegetated buffers of different designs are often used as edge-of-field treatment practices. Two experimental systems, a control (no vegetation) and a grass-wetla...

  3. A Connectionist Model of Attentional Enhancement and Signal Buffering

    DTIC Science & Technology

    1990-07-01

    removed (e.g., Sperling 1960). Humans can also buffer information in short-term memory while encoding and acting on new information ( Klapp , Marshburn...Stroop effect. Psychological Review. Klapp , S. T., Marshburn, E. A., & Lester, P. T. (1983). Short-term memory does not involve the "working memory

  4. The Design and Implementation of a Read Prediction Buffer

    DTIC Science & Technology

    1992-12-01

    distribution is unlimited THE DESIGN AND IMPLEMENTATION OF A READ PREDICTION BUFFER by Gary Joseph Nowicki Lieutenant, United States Navy B.S.E.E., University...EMAT >000000000000:AMWR >1 I II I00I II0I0:ERO >000000000000:DVA >000000000000:AMWR >000000000000:CAR >00000000: ODV >000000000000:PAMR >000000000000:SUB

  5. Odor mitigation with vegetative buffers: Swine production case study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetative environmental buffers (VEB) are a potentially low cost sustainable odor mitigation strategy, but there is little to no data supporting their effectiveness. Wind tunnel experiments and field monitoring were used to determine the effect VEB had on wind flow patterns within a swine facility....

  6. Seasonal hydrologic buffer on continents: Patterns, drivers and ecological benefits

    NASA Astrophysics Data System (ADS)

    Kuppel, Sylvain; Fan, Ying; Jobbágy, Esteban G.

    2017-04-01

    Continental precipitation returns to the atmosphere and the ocean with a delay that is critical in regulating seasonal water supply to ecosystems and societies. We quantify the magnitude and spatial patterns of this seasonal hydrologic buffer, its climatic and terrain drivers, and its apparent benefits to ecosystems using observed precipitation, climate reanalysis evaporation, GRACE seasonal water storage change, and MODIS vegetation index for a 1°× 1° global grid. We found that (1) seasonal hydrologic buffering is widespread and averages 241 mm.yr-1 on land (a quarter of continental precipitation); it supports evaporation 3-to-9 months of the year over all regions except the per-humid tropics and energy limited high latitudes, (2) the seasonal climatic water imbalance, with surplus in some months and deficit in others, drives hydrologic buffering in lower latitudes, while it is controlled by snow/ice storage in high latitudes, (3) the main terrain effect at our scale of analysis is grid-to-grid water transfer via large rivers providing lateral subsidy to lowland basins, and (4) buffering is manifested in global patterns of plant water use, as shown by high evaporation levels in water deficit conditions, particularly under tropical monsoonal climate. Our results highlight the paramount role of seasonal land water storage and redistribution in supporting ecosystem productivity, and provide a reference to understanding likely impacts of global change on the water cycle and ecosystem dynamics in the future.

  7. Substrate-induced magnetism in epitaxial graphene buffer layers.

    PubMed

    Ramasubramaniam, A; Medhekar, N V; Shenoy, V B

    2009-07-08

    Magnetism in graphene is of fundamental as well as technological interest, with potential applications in molecular magnets and spintronic devices. While defects and/or adsorbates in freestanding graphene nanoribbons and graphene sheets have been shown to cause itinerant magnetism, controlling the density and distribution of defects and adsorbates is in general difficult. We show from first principles calculations that graphene buffer layers on SiC(0001) can also show intrinsic magnetism. The formation of graphene-substrate chemical bonds disrupts the graphene pi-bonds and causes localization of graphene states near the Fermi level. Exchange interactions between these states lead to itinerant magnetism in the graphene buffer layer. We demonstrate the occurrence of magnetism in graphene buffer layers on both bulk-terminated as well as more realistic adatom-terminated SiC(0001) surfaces. Our calculations show that adatom density has a profound effect on the spin distribution in the graphene buffer layer, thereby providing a means of engineering magnetism in epitaxial graphene.

  8. Spatial buffering of potassium ions in brain extracellular space.

    PubMed Central

    Chen, K C; Nicholson, C

    2000-01-01

    It has long been assumed that one important mechanism for the dissipation of local potassium gradients in the brain extracellular space is the so-called spatial buffer, generally associated with glial cells. To date, however, there has been no analytical description of the characteristic patterns of K(+) clearance mediated by such a mechanism. This study reanalyzed a mathematical model of Gardner-Medwin (1983, J. Physiol. (Lond.). 335:393-426) that had previously been solved numerically. Under suitable approximations, the transient solutions for the potassium concentrations and the corresponding membrane potentials of glial cells in a finite, parallel domain were derived. The analytic results were substantiated by numerical simulations of a detailed two-compartment model. This simulation explored the dependence of spatial buffer current and extracellular K(+) on the distribution of inward rectifier K(+) channels in the glial endfoot and nonendfoot membranes, the glial geometric length, and the effect of passive KCl uptake. Regarding the glial cells as an equivalent leaky cable, the analyses indicated that a maximum endfoot current occurs when the glial geometric length is equal to the corresponding electrotonic space constant. Consequently, a long glial process is unsuitable for spatial buffering, unless the axial space constant can match the length of the process. Finally, this study discussed whether the spatial buffer mechanism is able to efficiently transport K(+) over distances of more than several glial space constants. PMID:10827962

  9. Effects of terrestrial buffer zones on amphibians on golf courses.

    PubMed

    Puglis, Holly J; Boone, Michelle D

    2012-01-01

    A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians.

  10. A model for monitoring of Hsp90-buffered genetic variations

    NASA Astrophysics Data System (ADS)

    Kozeko, Liudmyla

    Genetic material of terrestrial organisms can be considerably injured by cosmic rays and UV-radiation in the space environment. Organisms onboard are also exposed to the entire complex of negative physical factors which can generate genetic variations and affect morphogenesis. However, species phenotypes must be robust to genetic variation, requiring "buffering" systems to ensure normal development. The molecular chaperone Hsp90 can serve as such "a buffer". It is important in the maturation and conformational regulation of a diverse set of signal transducers. The requirement of many principal regulatory proteins for Hsp90 renders entire metabolic pathways sensitive to impairment of its function. So inhibition of Hsp90 function can open cryptic genetic variations and produce morphological changes. In this paper, we present a model for monitoring of cryptic Hsp90-buffered genetic variations arising during exposure to space and spaceflight factors. This model has been developed with Arabidopsis thaliana seeds gathered in natural habitats with high anthropogenic pressure and wild type (Col-0) seeds subjected to negative influences (UV, heavy metals) experimentally. The phenotypic traits of early seedlings grown under reduction of Hsp90 activity were characterized to estimate Hsp90-buffered genetic variations. Geldanamycin was used as an inhibitor of Hsp90 function.

  11. Buffer placement & effeciency improves when topographic flowpaths are used

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Best Management Practices (BMPs) are used to protect streams by excluding cattle from riparian areas and to filter/buffer run-off flowing from high-intensity use and livestock concentration areas, such as feeding and watering stations. NRCS Conservation Practice Standard (PA-561) recommends placing ...

  12. Dominant oceanic bacteria secure phosphate using a large extracellular buffer

    PubMed Central

    Zubkov, Mikhail V.; Martin, Adrian P.; Hartmann, Manuela; Grob, Carolina; Scanlan, David J.

    2015-01-01

    The ubiquitous SAR11 and Prochlorococcus bacteria manage to maintain a sufficient supply of phosphate in phosphate-poor surface waters of the North Atlantic subtropical gyre. Furthermore, it seems that their phosphate uptake may counter-intuitively be lower in more productive tropical waters, as if their cellular demand for phosphate decreases there. By flow sorting 33P-phosphate-pulsed 32P-phosphate-chased cells, we demonstrate that both Prochlorococcus and SAR11 cells exploit an extracellular buffer of labile phosphate up to 5–40 times larger than the amount of phosphate required to replicate their chromosomes. Mathematical modelling is shown to support this conclusion. The fuller the buffer the slower the cellular uptake of phosphate, to the point that in phosphate-replete tropical waters, cells can saturate their buffer and their phosphate uptake becomes marginal. Hence, buffer stocking is a generic, growth-securing adaptation for SAR11 and Prochlorococcus bacteria, which lack internal reserves to reduce their dependency on bioavailable ambient phosphate. PMID:26198420

  13. Dominant oceanic bacteria secure phosphate using a large extracellular buffer.

    PubMed

    Zubkov, Mikhail V; Martin, Adrian P; Hartmann, Manuela; Grob, Carolina; Scanlan, David J

    2015-07-22

    The ubiquitous SAR11 and Prochlorococcus bacteria manage to maintain a sufficient supply of phosphate in phosphate-poor surface waters of the North Atlantic subtropical gyre. Furthermore, it seems that their phosphate uptake may counter-intuitively be lower in more productive tropical waters, as if their cellular demand for phosphate decreases there. By flow sorting (33)P-phosphate-pulsed (32)P-phosphate-chased cells, we demonstrate that both Prochlorococcus and SAR11 cells exploit an extracellular buffer of labile phosphate up to 5-40 times larger than the amount of phosphate required to replicate their chromosomes. Mathematical modelling is shown to support this conclusion. The fuller the buffer the slower the cellular uptake of phosphate, to the point that in phosphate-replete tropical waters, cells can saturate their buffer and their phosphate uptake becomes marginal. Hence, buffer stocking is a generic, growth-securing adaptation for SAR11 and Prochlorococcus bacteria, which lack internal reserves to reduce their dependency on bioavailable ambient phosphate.

  14. TRIO: Burst Buffer Based I/O Orchestration

    SciTech Connect

    Wang, Teng; Oral, H Sarp; Pritchard, Michael; Wang, Bin; Yu, Weikuan

    2015-01-01

    The growing computing power on leadership HPC systems is often accompanied by ever-escalating failure rates. Checkpointing is a common defensive mechanism used by scientific applications for failure recovery. However, directly writing the large and bursty checkpointing dataset to parallel filesystem can incur significant I/O contention on storage servers. Such contention in turn degrades the raw bandwidth utilization of storage servers and prolongs the average job I/O time of concurrent applications. Recently burst buffer has been proposed as an intermediate layer to absorb the bursty I/O traffic from compute nodes to storage backend. But an I/O orchestration mechanism is still desired to efficiently move checkpointing data from bursty buffers to storage backend. In this paper, we propose a burst buffer based I/O orchestration framework, named TRIO, to intercept and reshape the bursty writes for better sequential write traffic to storage severs. Meanwhile, TRIO coordinates the flushing orders among concurrent burst buffers to alleviate the contention on storage server bandwidth. Our experimental results reveal that TRIO can deliver 30.5% higher bandwidth and reduce the average job I/O time by 37% on average for data-intensive applications in various checkpointing scenarios.

  15. Buffering agents modify the hydration landscape at charged interfaces.

    PubMed

    Trewby, William; Livesey, Duncan; Voïtchovsky, Kislon

    2016-03-07

    Buffering agents are widely used to stabilise the pH of solutions in soft matter and biological sciences. They are typically composed of weak acids and bases mixed in an aqueous solution, and can interact electrostatically with charged surfaces such as biomembranes. Buffers can induce protein aggregation and structural modification of soft interfaces, but a molecular-level picture is still lacking. Here we use high-resolution atomic force microscopy to investigate the effect of five commonly used buffers, namely 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), 2-(N-morpholino)ethanesulfonic acid (MES), monosodium phosphate, saline sodium citrate (SSC) and tris(hydroxymethyl)aminomethane (Tris) on the hydration landscape of Muscovite mica in solution. Mica is an ideal model substrate due to its negative surface charge and identical lattice parameter when compared with gel-phase lipid bilayers. We show that buffer molecules can produce cohesive aggregates spanning over tens of nanometres of the interface. SSC, Tris and monosodium phosphate tend to create an amorphous mesh layer several molecules thick and with no preferential ordering. In contrast, MES and HEPES adopt epitaxial arrangements commensurate with the underlying mica lattice, suggesting that they offer the most suitable solution for high-resolution studies. To confirm that this effect persisted in biologically-relevant interfaces, the experiments were repeated on a silica-supported lipid bilayer. Similar trends were observed for this system using atomic force microscopy as well as ellipsometry. The effect of the buffering agents can be mitigated by the inclusion of salt which helps displace them from the interface.

  16. Analysis of experimental data from a 50-mm railgun driven by a 5-MJ capacitor power supply

    NASA Astrophysics Data System (ADS)

    Scanlon, James J., III; Batteh, Jad H.; Thornhill, Lindsey D.; Jamison, Keith A.; Littrell, Donald M.

    1993-01-01

    Results are presented of recent testing of the Compact High Energy Capacitor Module Advanced Test Experiment coupled with a 5-MJ capacitor power supply, which was conducted using molybdenum coated rails, G-9 insulators, and a plasma armature. The potential mechanisms which lead to performance degradation at high velocities are identified and assessed. The present Electric Gun Circuit Analysis Code (EGCAC) is found to exhibit good agreement with experimental B-dot data up to approximately 3.5 km/s; however, on the higher voltage shots, EGCAC overpredicts the expected velocity. A discussion of this discrepancy along with the models used to resolve this difference are presented.

  17. Do calcium buffers always slow down the propagation of calcium waves?

    PubMed

    Tsai, Je-Chiang

    2013-12-01

    Calcium buffers are large proteins that act as binding sites for free cytosolic calcium. Since a large fraction of cytosolic calcium is bound to calcium buffers, calcium waves are widely observed under the condition that free cytosolic calcium is heavily buffered. In addition, all physiological buffered excitable systems contain multiple buffers with different affinities. It is thus important to understand the properties of waves in excitable systems with the inclusion of buffers. There is an ongoing controversy about whether or not the addition of calcium buffers into the system always slows down the propagation of calcium waves. To solve this controversy, we incorporate the buffering effect into the generic excitable system, the FitzHugh-Nagumo model, to get the buffered FitzHugh-Nagumo model, and then to study the effect of the added buffer with large diffusivity on traveling waves of such a model in one spatial dimension. We can find a critical dissociation constant (K = K(a)) characterized by system excitability parameter a such that calcium buffers can be classified into two types: weak buffers (K ∈ (K(a), ∞)) and strong buffers (K ∈ (0, K(a))). We analytically show that the addition of weak buffers or strong buffers but with its total concentration b(0)(1) below some critical total concentration b(0,c)(1) into the system can generate a traveling wave of the resulting system which propagates faster than that of the origin system, provided that the diffusivity D1 of the added buffers is sufficiently large. Further, the magnitude of the wave speed of traveling waves of the resulting system is proportional to √D1 as D1 --> ∞. In contrast, the addition of strong buffers with the total concentration b(0)(1) > b(0,c)(1) into the system may not be able to support the formation of a biologically acceptable wave provided that the diffusivity D1 of the added buffers is sufficiently large.

  18. Ultrasonic monitoring of material processing using clad buffer rod sensors

    NASA Astrophysics Data System (ADS)

    Ramos Franca, Demartonne

    Ultrasonic sensors and techniques are developed for in-line monitoring of polymer extrusion, cleanliness of molten metals and liquid flow speed at elevated temperature. Pulse-echo mode is used for the first two processes, while the through-transmission mode is applied in the third one. The ultrasonic probe consists of high performance clad buffer rods with different dimensions to thermally isolate the commercial ultrasonic transducer from materials at high temperature. The clad buffer rods are made of steel, polymer and ceramic. Steel clad buffer rods are introduced for in-line monitoring of polymer extrusion processes. Owing to its superior performance in pulse-echo mode, for the first time such a probe is installed and performs ultrasonic monitoring in the die of a co-extrusion machine and in the barrel section of a twin-screw extruder. It can reveal a variety of information relevant to process parameters, such as polymer layer thickness, interface location and adhesion quality, stability, or polymer composition change. For the ultrasonic monitoring of polymer processes, probes with acoustic impedance that matches that of the processed polymer may offer certain advantages such as quantitative viscoelastic evaluation; thus high temperature polymer clad buffer rods, in particular PEEK, are developed. It is demonstrated that this new probe exhibits unique advantages for in-line monitoring of the cure of epoxies and polymer extrusion process. Long steel clad buffer rods with a spherical focus lens machined at the probing end are proposed for cleanliness evaluation of molten metals. The potential of this focusing probe is demonstrated by means of high-resolution imaging and particles detection in molten zinc at temperatures higher than 600°C, using a single probe operated at pulse-echo mode. A contrapropagating ultrasonic flowmeter employing steel clad buffer rods is devised to operate at high temperature. It is demonstrated that these rods guide ultrasonic signals

  19. Bryophyte responses to microclimatic edge effects across riparian buffers.

    PubMed

    Stewart, Katherine J; Mallik, Azim U

    2006-08-01

    Although riparian buffers are an important aspect of forest management in the boreal forest of Canada, little is known about the habitat conditions within buffers, due in part to complex edge effects in response to both the upland clearcut and the stream. We investigated microclimatic conditions and bryophyte growth and vitality in seven locations between the stream edge and 60 m into the upland undisturbed conifer forests and at the clearcut sites with riparian buffer 30 km northwest of Thunder Bay, Ontario, Canada. We hypothesized that the growth and vitality of a pleurocarpous moss, Hylocomium splendens, and an acrocarpous moss, Polytrichum commune, would be directly related to the microclimatic gradients detected. We further hypothesized that sensitivity of the bryophytes to environmental factors will vary depending on their life form type, i.e., pleurocarpous moss will respond differently than the acrocarpous moss. Both bryophyte species were transplanted in pots and placed at 10-m intervals along 60-m transects perpendicular to the stream across the buffer and undisturbed sites. Bryophyte growth, cover, and vitality, as well as microclimatic parameters and plant cover, were measured over the summer in 2003. The riparian buffers were simultaneously affected by microclimatic gradients extending from both the clearcut edge and the riparian-upland ecotonal edge. Both bryophyte species responded to changes in the microclimatic conditions. However, vapor pressure deficit (VPD) was the most important factor influencing the growth of H. splendens, whereas for P. commune growth soil moisture was most important. Our study confirms earlier findings that interior forest bryophytes such as H. splendens can be used as indicators to monitor edge effects and biodiversity recovery following forest harvesting. We demonstrate that growth and vitality of these bryophytes reflect the prevailing near-ground microclimatic conditions at the forest edges. Abundance estimates of such

  20. Assessment and preliminary design of an energy buffer for regenerative braking in electric vehicles

    NASA Technical Reports Server (NTRS)

    Buchholz, R.; Mathur, A. K.

    1979-01-01

    Energy buffer systems, capable of storing the vehicle energy during braking and reusing this stored energy during acceleration, were examined. Some of these buffer systems when incorporated in an electric vehicle would result in an improvement in the performance and range under stop and go driving conditions. Buffer systems considered included flywheels, hydropneumatic, pneumatic, spring, and regenerative braking. Buffer ranking and rating criteria were established. Buffer systems were rated based on predicted range improvements, consumer acceptance, driveability, safety, reliability and durability, and initial and life cycle costs. A hydropneumatic buffer system was selected.

  1. Initial activity and inactivation of alkaline phosphatase in different lots of buffer.

    PubMed

    Pekelharing, J M; Leijnse, B

    1978-05-02

    Alkaline phosphatase activities were determined in six lots of 2-amino-2-methyl-1-propanol (AMP) and in six lots of diethanolamine (DEA) buffers without preincubation of the sample. There appeared to be differences between the lot numbers in both cases, resulting in a variation in initial activity. When serum samples are preincubated with buffer a loss of activity was observed in 4 out of the 6 AMP buffers. Four human isoenzymes showed varying inactivation during preincubation with AMP buffer. No loss of activity was observed when the preincubation was done with the six DEA buffers. These results indicate that the purity of the commercially-available buffers is quite unsatisfactory.

  2. Yin and Yang of Heparanase in Breast Tumor Initiation

    DTIC Science & Technology

    2013-04-01

    Nonidet P (NP)- 40 lysis buffer (50 mM Tris-HCl (pH 8.0), 150 mM NaCl, 1% NP- 40 , 5 mM EDTA, 10 µg/ml aprotinin, 10 µg/ml leupeptinin, and 1 mM...532- 40 . 28. Xu X, Quiros RM, Gattuso P , Ain KB, and Prinz RA High prevalence of BRAF gene mutation in papillary thyroid carcinomas and thyroid tumor...enzymatic activity. Neu, mice enco brea trans TVA sugg Fig. form old) 8C (red each palp and ( p ɘ Fi RC an lev lin

  3. Novel Therapeutic Approaches Toward Treating Prostate Cancer

    DTIC Science & Technology

    2012-05-01

    Nonidet P - 40 , 0.5% deoxycholate, 0.1%SDS), thenwashed twice in 1 kinase buffer (25 mM Tris-HCl, pH 7.5, 5 mM -glycerophosphate, 2 mM dithiothreitol, 0.1...2003) J. Biol. Chem. 278, 32390–32396 40 . Kim, S. Y., Herbst, A., Tworkowski, K.A., Salghetti, S. E., andTansey,W. P . (2003)Mol. Cell 11, 1177–1188 41...I p -PR . 40 :==================~ L.....--_____ _____.1 - ctin Figure 2: PIM-1 mRNA levels are stimulated by AKT inhibitors. PC3-LN4 were treated

  4. The Mechanism of Action of Unique Small Molecules that Inhibit the Pim Protein Kinase Blocking Prostate Cancer Cell Growth

    DTIC Science & Technology

    2010-05-01

    Chen, L., and Liu, X. (2003) J Biol Chem 278, 32390-32396 40 . Kim, S. Y., Herbst, A., Tworkowski, K. A., Salghetti, S. E., and Tansey, W. P . (2003) Mol...as described ( 40 ). HEK293T cells were transfected with the indicated plasmids for 24 h, treated with 10 μM MG132 for 6 h, and lysed in denaturing...from HEK293T cells. Immune complexes were washed three times in RIPA lysis buffer (150 mM NaCl, 10 mM Tris-HCl pH 7.5, 1% Nonidet P40, 0.5

  5. Analysis of p21-Activated Kinase Function in Neurofibromatosis Type 2

    DTIC Science & Technology

    2010-01-01

    PBS and lysed in a buffer containing 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 1% Nonidet P - 40 , and 0.25% sodium deoxycholate, 1 mM Na3VO4, and 1 mM NaF... P - 40 , 10 mM NaCl, 50 µg/ml propidium iodide and 70 Kunitz units/ml RNase A. FACS analysis was performed using CELLQuest™ software (Becton...and differences were considered statistically significant at P < 0.05. Results Chernoff, Jonathan 40 Establishing Merlin-deficient cells that

  6. Suppression of BRCA2 by Mutant Mitochondrial DNA in Prostate Cancer

    DTIC Science & Technology

    2011-05-01

    Nonidet P - 40 , 2 mmol/L phenylmethylsulfonyl fluoride, 10 g/mL aprotinin, 10 g/mL leupeptin, 10 mmol/L sodium fluoride, 1 mmol/L sodium orthovanadate, and...specimens were pulverized and homogenized in lysis buffer containing 0.1% SDS, 1% Non- idet P - 40 , 50 mmol/L Tris-HCl (pH 7.5), 150 mmol/L NaCl, 200...Analyze the correlation between type/number of mtDNA mutations and clinical stage (Months 10-11) We extracted total DNA from 6 BPH and 40 PCA frozen

  7. Plaque Transfer Assay for Detecting Neutralizing Antibodies to HTLV-3 (AIDS). HIV-1 Inactivation by Antibodies: Predominance of a Group-Specific Epitope that Persists Despite Genetic Variation

    DTIC Science & Technology

    1989-05-01

    TELEPHONE (Include Area Code) 22c. OFFICE SYMBOL Mrs. Virginia M . Miller 301/663-7325 SGRD- DO Form 1473, JUN 86 Previous editions are obsolete. SECURITY...dish and the monolayer was washed with phosphate buffered saline. Pre-cut circles of nitrocellulose paper, saturated with 0.05 M Tris-HCl pH 7 and...0.15 M NaCl were placed on the cell monolayer surface and pressed down firmly enough to make contact, but carefully to avoid smudging. The discs were

  8. Expression of Neuronal and Inducible Nitric Oxide Synthase Isoforms and Generation of Protein Nitrotyrosine in Rat Brain Following Hypobaric Hypoxia

    DTIC Science & Technology

    2001-06-01

    mM Tris-HCl buffer, pH 6.8, containing 2% w/v SDS, 10% v/v glycerol and 10mM 1,4-dithiothreitol. Proteins were separated by SDS-PAGE in 7.5% gels for...nNOS and 12.5% gels for protein nitrotyrosine, in a Bio-Rad Mini-Protein II apparatus (Bio-Rad, Madrid, Spain), and were then electroblotted onto 0.2...at monthly intervals thereafter, and the animals were bled from the marginal ear vein 14 days after each boost. Antibody titers were checked by

  9. Proteolytic Processing of Laminin-332 by Hepsin and Matriptase and Its Role in Prostate Cancer Progression

    DTIC Science & Technology

    2010-09-01

    to see invadopodia formation in PC3 cells failed (Figure 1). It has been shown in the literature that invadopodia can be induced in vitro by plating...CO2 at 37 °C. Purification of Rat Ln-332— Rat Ln-332 was purified from spent medium of 804G bladder squamous cell carcinoma cells. Briefly, 804G cells...sulfate at 80% saturation and dialyzed against 20 mM Tris-HCl (pH 7.5), 0.5 M NaCl, 0.005% Brij-35 ( TNB buffer). The concentrated serum-free

  10. Electrophoretic Characteristics of Outer Membrane Proteins of Neisseria meningitidis,

    DTIC Science & Technology

    1987-07-01

    prepared from a monomer stock of 3007o (w/v) acrylamide (Sigma Chemical Company, St. Louis, Missouri) and 0.8% (w/v) N,N- methylene -bis-acrylamide...buffer containing 0.05 M Tris-HCl (pH 6.8), 10% SDS, 10% glycerol, a pinch of bromophenol blue , and 17o 2-mercaptoethanol, such that all aliquots...Brilliant Blue /Silver Stain: Upon completion of electrophoresis, gels were stained for I h in a solution of Coomassie brilliant blue R250 (Sigma

  11. Analysis of Hybrid Buffering and Retransmission in OBS Networks.

    PubMed

    Vanitha, D Veera; Sabrigiriraj, M

    2015-01-01

    Burst contention is a major problem in the Optical Burst Switching (OBS) networks. Due to inadequate contention resolution techniques, the burst loss is prominent in OBS. In order to resolve contention fiber delay lines, wavelength converters, deflection routing, burst segmentation, and retransmission are used. Each one has its own limitations. In this paper, a new hybrid scheme is proposed which combines buffering and retransmission, which increases the mean number of bursts processed in the system. In this hybrid method, retransmission with controllable arrival and uncontrollable arrival is analyzed. Normally all the bursts reach the first hop and few of them go for second hop to reach destination. After all the bursts reach the destination the server may go for maintenance activity or wait for the arrival of next burst. We model it as a batch arrival single server retrial queue with buffer. Numerical results are analyzed to show the mean number of bursts processed in the system with uncontrollable arrival and controllable arrivals.

  12. Advanced titania buffer layer architectures prepared by chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Kunert, J.; Bäcker, M.; Brunkahl, O.; Wesolowski, D.; Edney, C.; Clem, P.; Thomas, N.; Liersch, A.

    2011-08-01

    Chemical solution deposition (CSD) was used to grow high-quality (100) oriented films of SrTiO3 (STO) on CSD CaTiO3 (CTO), Ba0.1Ca0.9TiO3 (BCT) and STO seed and template layers. These template films bridge the lattice misfit between STO and the nickel-tungsten (NiW) substrate, assisting in dense growth of textured STO. Additional niobium (Nb) doping of the STO buffer layer reduces oxygen diffusion which is necessary to avoid undesired oxidation of the NiW. The investigated templates offer suitable alternatives to established standard buffer systems like La2Zr2O7 (LZO) and CeO2 for coated conductors.

  13. Semiconducting chalcogenide buffer layer for oxide heteroepitaxy on Si(001)

    NASA Astrophysics Data System (ADS)

    Schmidt, D. A.; Ohta, Taisuke; Lu, C.-Y.; Bostwick, Aaron A.; Yu, Q.; Rotenberg, Eli; Ohuchi, F. S.; Olmstead, Marjorie A.

    2006-05-01

    We report controlled laminar growth of a crystalline transition metal oxide on Si(001) without SiOx or silicide formation by utilizing the chalcogenide semiconductor gallium sesquiselenide (Ga2Se3) as a nonreactive buffer layer. Initial nucleation of both pure and Co-doped anatase (TiO2) is along Ga2Se3 nanowire structures, coalescing to a flat, multidomain film within two molecular layers. Arsenic-terminated Si(001) [Si(001):As] is stable against pure O2, but oxidizes when both Ti and O2 are present. The Si -TiO2 valence band offset using either buffer layer is about 2.8eV, producing a staggered band alignment.

  14. Social Support Can Buffer against Stress and Shape Brain Activity

    PubMed Central

    Hostinar, Camelia E.; Gunnar, Megan R.

    2015-01-01

    Social support from close relationship partners is an important resource for coping with stress, particularly during childhood. We discuss ethical challenges associated with studying stress and its social buffering in the laboratory, as well as emerging evidence regarding two potential neural substrates for the social buffering of stress: hypothalamic oxytocin activity and activation of areas in the prefrontal cortex associated with effective self-regulation. We also address the role of early-life social experiences in shaping brain development, as well as recommendations for practice and policy that would advance the ethical treatment of children and reduce social inequalities in early-life experiences and opportunities–e.g., investing in programs that prevent child maltreatment and facilitating access to high-quality child care for economically disadvantaged families. We also debate the ethical implications of using oxytocin nasal sprays to simulate the stress-reducing properties of social support and advise waiting for more evidence before recommending their use. PMID:26478822

  15. Reactions of buffers in cyanogen bromide-induced ligations.

    PubMed

    Vogel, Heike; Gerlach, Claudia; Richert, Clemens

    2013-01-01

    Rapid, template-directed ligation reactions between a phosphate-terminated oligonucleotide and an unphosphorylated reaction partner may be induced by cyanogen bromide (BrCN). Frequently, however, the reaction is low yielding, and even a large excess of the condensing agent can fail to induce quantitative conversions. In this study, we used BrCN to induce chemical primer extension reactions. Here, we report that buffers containing hydroxyl groups react with short oligodeoxynucleotides in the presence of BrCN. One stable adduct between HEPBS buffer and cytosine was characterized by mass spectrometry and NMR after HPLC purification, indicating that a side reaction occurred at this nucleobase. Further, a first example of a primer extension reaction between an unmodified oligodeoxynucleotide as primer and dGMP is reported. Together, our results shed light on the potency, as well as the drawbacks of BrCN as a highly reactive condensing reagent for the ligation of unmodified nucleic acids.

  16. CE-MS of antihistamines using nonvolatile phosphate buffer.

    PubMed

    Chien, Chiu-Tang; Li, Fu-An; Huang, Ju-Li; Her, Guor-Rong

    2007-05-01

    Antihistamines were analyzed by CE-ESI-MS using phosphate buffer. The separation was performed in an acidic environment so that phosphate ions had a net velocity flowing toward the inlet reservoir instead of the ESI source. To further reduce the effect of ion suppression, the sodium ion in sodium phosphate was replaced with an ammonium ion. Furthermore, with the combination of reducing the concentration of acid added to the sheath liquid and the use of a low-flow interface, phosphoric acid could be added to the sheath liquid. Because of the use of the same counterion (phosphate ion) in running buffer and in sheath liquid, the separation integrity (resolution, elution order, and peak shape) was preserved. In addition, ion suppression was also greatly alleviated because a minimal amount of phosphate flowed into the ESI source.

  17. A 128K-bit CCD buffer memory system

    NASA Technical Reports Server (NTRS)

    Siemens, K. H.; Wallace, R. W.; Robinson, C. R.

    1976-01-01

    A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. 8K-bit CCD shift register memories were used to construct a feasibility model 128K-bit buffer memory system. Peak power dissipation during a data transfer is less than 7 W., while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. Descriptions are provided of both the buffer memory system and a custom tester that was used to exercise the memory. The testing procedures and testing results are discussed. Suggestions are provided for further development with regards to the utilization of advanced versions of CCD memory devices to both simplified and expanded memory system applications.

  18. Buffered coscheduling for parallel programming and enhanced fault tolerance

    SciTech Connect

    Petrini, Fabrizio; Feng, Wu-chun

    2006-01-31

    A computer implemented method schedules processor jobs on a network of parallel machine processors or distributed system processors. Control information communications generated by each process performed by each processor during a defined time interval is accumulated in buffers, where adjacent time intervals are separated by strobe intervals for a global exchange of control information. A global exchange of the control information communications at the end of each defined time interval is performed during an intervening strobe interval so that each processor is informed by all of the other processors of the number of incoming jobs to be received by each processor in a subsequent time interval. The buffered coscheduling method of this invention also enhances the fault tolerance of a network of parallel machine processors or distributed system processors

  19. Intergenerational Links in Victimization: Prosocial Friends as a Buffer.

    PubMed

    Han, Sohyun C; Margolin, Gayla

    2016-06-01

    This study investigated whether having friends who engaged in more prosocial than antisocial behaviors buffered the associations between family-of-origin aggression and later victimization. Adolescent participants (N=125) and their parents reported on different types of family aggression in early adolescence. Approximately 5 years later, adolescents reported on their victimization experiences with dating partners and friends, and their friends' prosocial and antisocial behaviors. Only father-to-child aggression was significantly associated with dating and friend victimization, with stronger risk for females' dating victimization. Moreover, having friends who engaged in more prosocial than antisocial behaviors had both a direct inverse relationship with dating partner victimization. This also buffered the risk for dating victimization associated with father-daughter aggression. Findings suggest that greater attention be paid to the father-daughter relationship and to the importance of having friends who engage in prosocial behaviors in the prevention of adolescents' victimization.

  20. Desire to work as a death anxiety buffer mechanism.

    PubMed

    Yaakobi, Erez

    2015-01-01

    Four studies were conducted to examine the death anxiety buffering function of work as a terror management mechanism, and the possible moderating role of culture. In Study 1, making mortality salient led to higher reports of participants' desire to work. In Study 2, activating thoughts of fulfillment of the desire to work after mortality salience reduced the accessibility of death-related thoughts. In Study 3, activating thoughts of fulfillment of the desire to work reduced the effects of mortality salience on out-group derogation. In Study 4, priming thoughts about obstacles to the actualization of desire to work led to greater accessibility of death-related thoughts. Although two different cultures with contrasting work values were examined, the results were consistent, indicating that the desire to work serves as a death anxiety buffer mechanism in both cultures.

  1. Capillary-channeled polymer (C-CP) films as processing platforms for protein analysis by matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS).

    PubMed

    Pittman, Jennifer J; Manard, Benjamin T; Kowalski, Paul J; Marcus, R Kenneth

    2012-01-01

    Polypropylene (PP) capillary-channeled polymer (C-CP) films have parallel, μm-sized channels that induce solution wicking via capillary action. Efficient mass transport from the solution phase to the channel surface leads to adsorption of hydrophobic protein solutes. The basic premise by which C-CP films can be used as media to manipulate analyte solutions (e.g., proteins in buffer), for the purpose of desalting or chromatographic separation prior to MALDI-MS analysis is presented here. Cytochrome c and myoglobin prepared in a Tris-HCl buffer, and ribonuclease A, lysozyme, and transferrin prepared in phosphate buffered saline (PBS), are used as the test solutions to demonstrate the desalting concept. Protein analysis is performed after deposition on a C-CP film with and without a water washing step, followed by spray deposition of a typical sinapinic acid matrix. Extracted MALDI mass spectra exhibit much improved signal-to-noise characteristics after water washing. A mixture of cytochrome c and myoglobin (2 μL of 2.5 μM each in Tris-HCl buffer) was applied, washed with water and spatially separated via simple capillary action (wicking) using a reversed-phase solvent composition of 0.1% trifluoroacetic acid (TFA) in 50:50 acetonitrile (ACN):H(2)O. Subsequent application of sinapinic acid followed by imaging of the film using MALDI-MS reveals that as the protein solution is wicked down the film, separation occurs.

  2. Capillary-Channeled Polymer (C-CP) Films as Processing Platforms for Protein Analysis by Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry (MALDI-MS)

    NASA Astrophysics Data System (ADS)

    Pittman, Jennifer J.; Manard, Benjamin T.; Kowalski, Paul J.; Marcus, R. Kenneth

    2012-01-01

    Polypropylene (PP) capillary-channeled polymer (C-CP) films have parallel, μm-sized channels that induce solution wicking via capillary action. Efficient mass transport from the solution phase to the channel surface leads to adsorption of hydrophobic protein solutes. The basic premise by which C-CP films can be used as media to manipulate analyte solutions (e.g., proteins in buffer), for the purpose of desalting or chromatographic separation prior to MALDI-MS analysis is presented here. Cytochrome c and myoglobin prepared in a Tris-HCl buffer, and ribonuclease A, lysozyme, and transferrin prepared in phosphate buffered saline (PBS), are used as the test solutions to demonstrate the desalting concept. Protein analysis is performed after deposition on a C-CP film with and without a water washing step, followed by spray deposition of a typical sinapinic acid matrix. Extracted MALDI mass spectra exhibit much improved signal-to-noise characteristics after water washing. A mixture of cytochrome c and myoglobin (2 μL of 2.5 μM each in Tris-HCl buffer) was applied, washed with water and spatially separated via simple capillary action (wicking) using a reversed-phase solvent composition of 0.1% trifluoroacetic acid (TFA) in 50:50 acetonitrile (ACN):H2O. Subsequent application of sinapinic acid followed by imaging of the film using MALDI-MS reveals that as the protein solution is wicked down the film, separation occurs.

  3. Experimental study on the optimization of general conditions for a free-flow electrophoresis device with a thermoelectric cooler.

    PubMed

    Yan, Jian; Yang, Cheng-Zhang; Zhang, Qiang; Liu, Xiao-Ping; Kong, Fan-Zhi; Cao, Cheng-Xi; Jin, Xin-Qiao

    2014-12-01

    With a given free-flow electrophoresis device, reasonable conditions (electric field strength, carrier buffer conductivity, and flow rate) are crucial for an optimized separation. However, there has been no experimental study on how to choose reasonable general conditions for a free-flow electrophoresis device with a thermoelectric cooler in view of Joule heat generation. Herein, comparative experiments were carried out to propose the selection procedure of general conditions in this study. The experimental results demonstrated that appropriate conditions were (i) <67 V/cm electric field strength; (ii) lower than 1.3 mS/cm carrier buffer conductivity (Tris-HCl: 20 mM Tris was titrated by HCl to pH 8.0); and (iii) higher than 3.6 mL/min carrier buffer flow rate. Furthermore, under inappropriate conditions (e.g. 400 V voltage and 40 mM Tris-HCl carrier buffer), the free-flow electrophoresis separation would be destroyed by bubbles caused by more Joule heating. Additionally, a series of applications under the appropriate conditions were performed with samples of model dyes, proteins (bovine serum albumin, myoglobin, and cytochrome c), and cells (Escherichia coli, Streptococcus thermophilus, and Saccharomyces cerevisiae). The separation results showed that under the appropriate conditions, separation efficiency was obviously better than that in the previous experiments with randomly or empirically selected conditions.

  4. Radiation inactivation reveals discrete cation binding sites that modulate dihydropyridine binding sites

    SciTech Connect

    Bolger, G.T.; Skolnick, P.; Kempner, E.S. )

    1989-08-01

    In low ionic strength buffer (5 mM Tris.HCl), the binding of (3H) nitrendipine to dihydropyridine calcium antagonist binding sites of mouse forebrain membranes is increased by both Na{sup +} and Ca{sup 2+}. Radiation inactivation was used to determine the target size of ({sup 3}H)nitrendipine binding sites in 5 mM Tris.HCl buffer, in the presence and absence of these cations. After irradiation, ({sup 3}H) nitrendipine binding in buffer with or without Na+ was diminished, due to a loss of binding sites and also to an increase in Kd. After accounting for radiation effects on the dissociation constant, the target size for the nitrendipine binding site in buffer was 160-170 kDa and was 170-180 kDa in the presence of sodium. In the presence of calcium ions, ({sup 3}H)nitrendipine binding showed no radiation effects on Kd and yielded a target size of 150-170 kDa. These findings suggest, as in the case of opioid receptors, the presence of high molecular weight membrane components that modulate cation-induced alterations in radioligand binding to dihydropyridine binding sites.

  5. Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

    2010-01-01

    Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

  6. Fast Pixel Buffer For Processing With Lookup Tables

    NASA Technical Reports Server (NTRS)

    Fisher, Timothy E.

    1992-01-01

    Proposed scheme for buffering data on intensities of picture elements (pixels) of image increases rate or processing beyond that attainable when data read, one pixel at time, from main image memory. Scheme applied in design of specialized image-processing circuitry. Intended to optimize performance of processor in which electronic equivalent of address-lookup table used to address those pixels in main image memory required for processing.

  7. Complete NMR analysis of oxytocin in phosphate buffer.

    PubMed

    Ohno, Akiko; Kawasaki, Nana; Fukuhara, Kiyoshi; Okuda, Haruhiro; Yamaguchi, Teruhide

    2010-02-01

    Complete NMR analysis of oxytocin (OXT) in phosphate buffer was elucidated by one-dimensional (1D)- and two-dimensional (2D)-NMR techniques, which involve the assignment of peptide amide NH protons and carbamoyl NH(2) protons. The (1)H-(15)N correlation of seven amide NH protons and three carbamoyl NH(2) protons were also shown by HSQC NMR of OXT without (15)N enrichment.

  8. HFB : A FASTBUS multi event double port buffer memory

    SciTech Connect

    Cerrito, L.; Lebbolo, H.

    1986-02-01

    The authors describe here the FB double port buffer memory developed at the LPNHE of the University Paris VI. Its purposes are to make available same features useful in the High Energy environment, to reduce, for a given amount of memory, the dead time data collection in a large size (in term of read-out channels) High Energy experiment and to get a buffer of memory as cheap and reliable as possible. The FB protocol, on the crate and cable side, is exploited using the coupler on 4 PAL's developed by G.Fremont and E.Sanchis. The DATA-Space is divided in 4 independent smaller blocks in a way such that a block can be accessed from a port while a different block is accessed from the other port. The two ports are: A, the FB crate port and B, the FB cable port. The buffer works as a rotary FIFO, looping over the 4 blocks of memory, but allowing for any random access. A mechanism is implemented on the board in order to be able to link different modules placed everywhere. If there are m modules, the looping will be around m 4 memory blocks. A multi event function is implemented on the board. HFB is quiped of two NTA for the DATA-Space on the port ''A'', and a flag to choose between them, to allow for a FB spying of DATA during the DAS dead time. HFB is a buffer of memory which can be used at each stage of a DAS: Frontend, Intermediate (MEB) or final, being completely FB standard. The HFB was designed for the LEP data acquisition system.

  9. Buffer layers on metal alloy substrates for superconducting tapes

    DOEpatents

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-06-29

    An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected IC's of over 200 Amperes across a sample 1 cm wide.

  10. Mass spectrometry-guided refinement of chemical energy buffers.

    PubMed

    Chen, T-R; Urban, P L

    2016-06-01

    Biocatalytic reactions often require supplying chemical energy and phosphate groups in the form of adenosine triphosphate (ATP). Auxiliary enzymes can be used to convert a reaction by-product-adenosine diphosphate (ADP)-back to ATP. By employing real-time mass spectrometry (RTMS), one can gain an insight into inter-conversions of reactants in multi-enzyme reaction systems and optimize the reaction conditions. In this study, temporal traces of ions corresponding to adenosine monophosphate (AMP), ADP and ATP provided vital information that could be used to adjust activities of the 'buffering enzymes'. Using the RTMS results as a feedback, we also characterized a bienzymatic energy buffer that enables the recovery of ATP in the cases where it is directly hydrolysed to AMP in the main enzymatic reaction. The significance of careful selection of enzyme activities-guided by RTMS-is exemplified in the synthesis of glucose-6-phosphate by hexokinase in the presence of a buffering enzyme, pyruvate kinase. Relative activities of the two enzymes, present in the reaction mixture, influence biosynthetic reaction yields. This observation supports the conclusion that optimization of chemical energy recycling procedures is critical for the biosynthetic reaction economy.

  11. Magnetic bearings for a high-performance optical disk buffer

    NASA Technical Reports Server (NTRS)

    Hockney, Richard; Hawkey, Timothy

    1993-01-01

    An optical disk buffer concept can provide gigabit-per-second data rates and terabit capacity through the use of arrays of solid state lasers applied to a stack of erasable/reusable optical disks. The RCA optical disk buffer has evoked interest by NASA for space applications. The porous graphite air bearings in the rotary spindle as well as those used in the linear translation of the read/write head would be replaced by magnetic bearings or mechanical (ball or roller) bearings. Based upon past experience, roller or ball bearings for the translation stages are not feasible. Unsatisfactory, although limited experience exists with ball bearing spindles also. Magnetic bearings, however, appear ideally suited for both applications. The use of magnetic bearings is advantageous in the optical disk buffer because of the absence of physical contact between the rotating and stationary members. This frictionless operation leads to extended life and reduced drag. The manufacturing tolerances that are required to fabricate magnetic bearings would also be relaxed from those required for precision ball and gas bearings. Since magnetic bearings require no lubricant, they are inherently compatible with a space (vacuum) environment. Magnetic bearings also allow the dynamics of the rotor/bearing system to be altered through the use of active control. This provides the potential for reduced vibration, extended regions of stable operation, and more precise control of position.

  12. Cell Electrosensitization Exists Only in Certain Electroporation Buffers

    PubMed Central

    Dermol, Janja; Pakhomova, Olga N.; Pakhomov, Andrei G.; Miklavčič, Damijan

    2016-01-01

    Electroporation-induced cell sensitization was described as the occurrence of a delayed hypersensitivity to electric pulses caused by pretreating cells with electric pulses. It was achieved by increasing the duration of the electroporation treatment at the same cumulative energy input. It could be exploited in electroporation-based treatments such as electrochemotherapy and tissue ablation with irreversible electroporation. The mechanisms responsible for cell sensitization, however, have not yet been identified. We investigated cell sensitization dynamics in five different electroporation buffers. We split a pulse train into two trains varying the delay between them and measured the propidium uptake by fluorescence microscopy. By fitting the first-order model to the experimental results, we determined the uptake due to each train (i.e. the first and the second) and the corresponding resealing constant. Cell sensitization was observed in the growth medium but not in other tested buffers. The effect of pulse repetition frequency, cell size change, cytoskeleton disruption and calcium influx do not adequately explain cell sensitization. Based on our results, we can conclude that cell sensitization is a sum of several processes and is buffer dependent. Further research is needed to determine its generality and to identify underlying mechanisms. PMID:27454174

  13. The buffer value of groundwater when well yield is limited

    NASA Astrophysics Data System (ADS)

    Foster, T.; Brozović, N.; Speir, C.

    2017-04-01

    A large proportion of the total value of groundwater in conjunctive use systems is associated with the ability to smooth out shortfalls in surface water supply during droughts. Previous research has argued that aquifer depletion in these regions will impact farmers negatively by reducing the available stock of groundwater to buffer production in future periods, and also by increasing the costs of groundwater extraction. However, existing studies have not considered how depletion may impact the productivity of groundwater stocks in conjunctive use systems through reductions in well yields. In this work, we develop a hydro-economic modeling framework to quantify the effects of changes in well yields on the buffer value of groundwater, and apply this model to an illustrative case study of tomato production in California's Central Valley. Our findings demonstrate that farmers with low well yields are forced to forgo significant production and profits because instantaneous groundwater supply is insufficient to buffer surface water shortfalls in drought years. Negative economic impacts of low well yields are an increasing function of surface water variability, and are also greatest for farmers operating less efficient irrigation systems. These results indicate that impacts of well yield reductions on the productivity of groundwater are an important economic impact of aquifer depletion, and that failure to consider this feedback may lead to significant errors in estimates of the value of groundwater management in conjunctive use systems.

  14. Comparison of Buffer Effect of Different Acids During Sandstone Acidizing

    NASA Astrophysics Data System (ADS)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham; Hamid, Mohamed Ali

    2015-04-01

    The most important concern of sandstone matrix acidizing is to increase the formation permeability by removing the silica particles. To accomplish this, the mud acid (HF: HCl) has been utilized successfully for many years to stimulate the sandstone formations, but still it has many complexities. This paper presents the results of laboratory investigations of different acid combinations (HF: HCl, HF: H3PO4 and HF: HCOOH). Hydrofluoric acid and fluoboric acid are used to dissolve clays and feldspar. Phosphoric and formic acids are added as a buffer to maintain the pH of the solution; also it allows the maximum penetration of acid into the core sample. Different tests have been performed on the core samples before and after the acidizing to do the comparative study on the buffer effect of these acids. The analysis consists of permeability, porosity, color change and pH value tests. There is more increase in permeability and porosity while less change in pH when phosphoric and formic acids were used compared to mud acid. From these results it has been found that the buffer effect of phosphoric acid and formic acid is better than hydrochloric acid.

  15. Electroejaculation and semen buffer evaluation in the microbat Carollia perspicillata.

    PubMed

    Fasel, Nicolas Jean; Helfenstein, Fabrice; Buff, Samuel; Richner, Heinz

    2015-03-15

    Scientific interests and conservation needs currently stress the necessity to better understanding bat reproductive biology. In this study, we present the first, safe, inexpensive, and reliable method to obtain sperm from a microbat species (Carollia perspicillata) by electroejaculation. This method revealed to be highly efficient (100% success rate). We obtained ejaculates composed of two characteristically different fractions. We compared three buffers and recommend using an Earle's balanced salt solution as a semen extender. Earle's balanced salt solution provided significant repeatable measure of swimming ability (intraclass correlation coefficient: 0.74, P < 0.01) and proportion of motile sperms (intraclass correlation coefficient: 0.08, P = 0.01) and allowed sperm to maintain optimal swimming capacity over time. None of the buffers could dissolve all the coagulated sperm. Although the trypsin buffer freed a larger fraction of spermatozoa in the ejaculate, it impaired swimming ability without improving motility, viability, and stamina. We thus argue that the sperm population analyzed with Earle's balanced salt solution is a representative of the ejaculate. Finally, we found that the mean sperm velocity of C perspicillata (78.8 μm/s) is lower than that predicted by regressing sperm velocity on relative testes mass, a proxy of sperm competition. The question as to whether C perspicillata is an outsider for sperm velocity, or whether bats evolved yet another unique mechanism to cope with sperm competition deserves more investigations.

  16. Does education buffer the impact of disability on psychological distress?

    PubMed

    Mandemakers, Jornt J; Monden, Christiaan W S

    2010-07-01

    This paper investigates whether education buffers the impact of physical disability on psychological distress. It further investigates what makes education helpful, by examining whether cognitive ability and occupational class can explain the buffering effect of education. Two waves of the 1958 British National Child Development Study are used to test the hypothesis that the onset of a physical disability in early adulthood (age 23 to 33) has a smaller effect on psychological distress among higher educated people. In total 423 respondents (4.6%) experienced the onset of a physical disability between the ages of 23 and 33. We find that a higher educational level cushions the psychology impact of disability. Cognitive ability and occupational class protect against the effect of a disability too. The education buffer arises in part because individuals with a higher level of education have more cognitive abilities, but the better social position of those with higher levels of education appears to be of greater importance. Implications of these findings for the social gradient in health are discussed.

  17. Plant metabolite profiles and the buffering capacities of ecosystems.

    PubMed

    Fester, Thomas

    2015-02-01

    In spite of some inherent challenges, metabolite profiling is becoming increasingly popular under field conditions. It has been used successfully to address topics like species interactions, connections between growth and chemical stoichiometry or the plant's stress response. Stress exerts a particularly clear impact on plant metabolomes and has become a central topic in many metabolite profiling experiments in the fields. In contrast to phytochambers, however, external stress is often at least partially absorbed by the environment when measuring under field conditions. Such stress-buffering capacities of (agro)-ecosystems are of crucial interest given the ever-increasing anthropogenic impact on ecosystems and this review promotes the idea of using plant metabolite profiles for respective measurements. More specifically I propose to use parameters of the response of key plant species to a given stress treatment as proxies for measuring and comparing stress-buffering capacities of ecosystems. Stress response parameters accessible by metabolite profiling comprise for example the intensity or duration of the impact of stress or the ability of the plant organism to recover from this impact after a given time. Analyses of ecosystem stress-buffering capacities may improve our understanding of how ecosystems cope with stress and may improve our abilities to predict ecosystem changes.

  18. Professional commitment: Does it buffer or intensify job demands?

    PubMed

    Nesje, Kjersti

    2017-04-01

    The purpose of this study is to investigate whether professional commitment can be seen as a moderator in the relationship between job demands and emotional exhaustion among Norwegian nurses. Inspired by the job demands-resources model, this study explores whether having a strong commitment to the nursing profession can be seen as a resource that buffers the effect of job demands on emotional exhaustion or, conversely, intensifies the impact of job demands. A survey that comprised Norwegian nurses who had graduated three years previously (N = 388) was conducted. Multiple regression was performed to test the hypothesis. The results provide support to a buffering effect; thus, individuals with a higher degree of professional commitment conveyed a weaker association between job demands and emotional exhaustion compared with nurses with a lower degree of commitment. Developing a better understanding of the potential buffering effect of professional commitment is of great interest. The present study is the first to utilize professional commitment as a resource within the job demands-resources framework.

  19. Wheeler County Riparian Buffers; 2002-2003 Annual Report.

    SciTech Connect

    Potter, Judy; Homer, Will

    2004-02-01

    Problems Encountered During Contract Year--Wheeler County residents are mostly non participants when it comes to Farm Services programs. Results of the counties non participation is the rental rates are the lowest in the state. There is a government fear factor as well as an obvious distance limitation. The FSA office is nearly 150 mile roundtrip from two of the counties urban areas. I find myself not only selling the CREP-Riparian Buffer but also selling Farm Services in general. Training has been very limited. NRCS is obviously not designed around training and certification. They are an on-the-job training organization. It has caused a hesitation in my outreach program and a great deal of frustration. I feel my confidence will strengthen with the follow through of the current projects. The most evident problem has come to light as of late. The program is too expensive to implement. The planting is too intensive for a 12''-18'' rainfall area. I provide the potential landowner a spread sheet with the bonuses, the costs, and the final outcome. No matter the situation, CREP or CCRP, the landowner always balks at the cost. The program assumes the landowner has the capital to make the initial investment. For example, project No.2 is going to be a minimum width buffer. It is approximately 3,000 ft long and 5.5 acres. The buffer for tree planting and fencing alone will result in a cost of nearly $13,000. With the water developments it nears $23,000. That is nearly 10% of a 250 mother-cow operating budget. Project No.1, the tree planting estimate is $45,000. This alone is nearly 25% of the same type of budget. I would greatly appreciate any help in finding a third party willing to put money to work covering the initial costs of the program, expecting reimbursement from Farm Services Agency. I believe this could create a powerful tool in buffering streams in Wheeler County. Outlook for Contract Year 2--I have been in this position now for 6 months. I am beginning to feel a

  20. Alkaline buffers release EDRF from bovine cultured aortic endothelial cells.

    PubMed Central

    Mitchell, J. A.; de Nucci, G.; Warner, T. D.; Vane, J. R.

    1991-01-01

    1. Release of endothelium-derived relaxing factor (EDRF) and prostacyclin (PGI2) from bovine cultured aortic endothelial cells (EC) was measured by bioassay and radioimmunoassay, respectively. 2. Bradykinin (BK, 3-30 pmol), adenosine diphosphate (ADP, 2-6 nmol) or the sodium ionophore monensin (40-100 nmol) injected through a column of EC released EDRF. L-Arginine free base (FB; 10-20 mumol) or D-arginine FB (10-20 mumol) injected through the column of EC released similar amounts of EDRF and also caused an increase in pH of the Krebs solution perfusing the EC from 7.5-8.0 to 8.6-9.5. Sodium carbonate (Na2CO3) an alkaline buffer which caused the same changes in the pH of the Krebs solution also induced the same release of EDRF. The hydrochloride salts of L- or D-arginine did not cause either release of EDRF when injected through the column of EC or increases in the pH of the Krebs solution. 3. Inhibitors of either diacylglycerol lipase (RHC 80267) or kinase (R59022) inhibited the release of EDRF induced by BK or ADP but potentiated the release induced by L-arginine FB, monensin (40-100 nmol) or alkaline buffer (Na2CO3). R59022 and RHC 80267 infused through the EC increased the basal release of EDRF. 4. When calcium chloride was omitted from the Krebs solution the release of EDRF induced by alkaline buffer (Na2CO3; pH 8.6-9.5) or L-arginine FB (10-20 mumol) was selectively inhibited when compared to that induced by BK (3-30 pmol) or ADP (2-6 nmol). This inhibition was reversed when calcium (2.5 mM) was restored. 5. NG-monomethyl-L-arginine (NMMA; 30 microM) inhibited release of EDRF induced by BK (10-30 pmol) or alkaline buffers (Na2CO3 or D-arginine FB; pH 8.6-9.5). This inhibition was partially reversed by L- but not D-arginine FB or HCl (30-100 microM). 6. Prostacyclin was released when BK (10 pmol), ADP (2 nmol) or arachidonic acid (30 nmol) were injected through the column of EC. However, monensin (40 nmol) or alkaline buffers (pH 8.6-9.5) did not release

  1. Analysis of Natural Buffer Systems and the Impact of Acid Rain

    ERIC Educational Resources Information Center

    Powers, David C.; Yoder, Claude H.; Higgs, Andrew T.; Obley, Matt L.; Hess, Kenneth R.; Leber, Phyllis A.

    2005-01-01

    The environmental significance of acid rain on water systems of different buffer capacities is discussed. The most prevalent natural buffer system is created by the equilibrium between carbonate ions and carbon dioxide.

  2. A temperature independent pH (TIP) buffer for biomedical biophysical applications at low temperatures.

    PubMed

    Sieracki, Nathan A; Hwang, Hee Jung; Lee, Michelle K; Garner, Dewain K; Lu, Yi

    2008-02-21

    A temperature independent pH buffer has been developed from a combination of buffers of opposite-sign temperature coefficients, and utility in low temperature spectroscopy and storage of pH sensitive compounds is demonstrated.

  3. Biochar contribution to soil pH buffer capacity

    NASA Astrophysics Data System (ADS)

    Tonutare, Tonu; Krebstein, Kadri; Utso, Maarius; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

    2014-05-01

    Biochar as ecologically clean and stable form of carbon has complex of physical and chemical properties which make it a potentially powerful soil amendment (Mutezo, 2013). Therefore during the last decade the biochar application as soil amendment has been a matter for a great number of investigations. For the ecological viewpoint the trend of decreasing of soil organic matter in European agricultural land is a major problem. Society is faced with the task to find possibilities to stabilize or increase soil organic matter content in soil and quality. The availability of different functional groups (e.g. carboxylic, phenolic, acidic, alcoholic, amine, amide) allows soil organic matter to buffer over a wide range of soil pH values (Krull et al. 2004). Therefore the loss of soil organic matter also reduces cation exchange capacity resulting in lower nutrient retention (Kimetu et al. 2008). Biochar can retain elements in soil directly through the negative charge that develops on its surfaces, and this negative charge can buffer acidity in the soil. There are lack of investigations about the effect of biochar to soil pH buffering properties, The aim of our investigation was to investigate the changes in soil pH buffer capacity in a result of addition of carbonizated material to temperate region soils. In the experiment different kind of softwood biochars, activated carbon and different soil types with various organic matter and pH were used. The study soils were Albeluvisols, Leptosols, Cambisols, Regosols and Histosols . In the experiment the series of the soil: biochar mixtures with the biochar content 0 to 100% were used. The times of equiliberation between solid and liquid phase were from 1 to 168 hours. The suspension of soil: biochar mixtures was titrated with HCl solution. The titration curves were established and pH buffer capacities were calculated for the pH interval from 3.0 to 10.0. The results demonstrate the dependence of pH buffer capacity from soil type

  4. 8-aminoquinoline functionalized silica nanoparticles: a fluorescent nanosensor for detection of divalent zinc in aqueous and in yeast cell suspension.

    PubMed

    Rastogi, Shiva K; Pal, Parul; Aston, D Eric; Bitterwolf, Thomas E; Branen, A Larry

    2011-05-01

    Zinc is one of the most important transition metal of physiological importance, existing primarily as a divalent cation. A number of sensors have been developed for Zn(II) detection. Here, we present a novel fluorescent nanosensor for Zn(II) detection using a derivative of 8-aminoquinoline (N-(quinolin-8-yl)-2-(3 (triethoxysilyl)propylamino)acetamide (QTEPA) grafted on silica nanoparticles (SiNPs). These functionalized SiNPs were used to demonstrate specific detection of Zn(II) in tris-HCl buffer (pH 7.22), in yeast cell (Saccharomyces cerevisiae) suspension, and in tap water. The silane QTEPA, SiNPs and final product were characterized using solution and solid state nuclear magnetic resonance, Fourier transform infrared, ultraviolet-visible absorption spectroscopy, transmission electron microscopy, elemental analysis, thermogravimetric techniques, and fluorescence spectroscopy. The nanosensor shows almost 2.8-fold fluorescence emission enhancement and about 55 nm red-shift upon excitation with 330 ± 5 nm wavelength in presence of 1 μM Zn(II) ions in tris-HCl (pH 7.22). The presence of other metal ions has no observable effect on the sensitivity and selectivity of nanosensor. This sensor selectively detects Zn(II) ions with submicromolar detection to a limit of 0.1 μM. The sensor shows good applicability in the determination of Zn(II) in tris-HCl buffer and yeast cell environment. Further, it shows enhancement in fluorescence intensity in tap water samples.

  5. On the delay analysis of a TDMA channel with finite buffer capacity

    NASA Technical Reports Server (NTRS)

    Yan, T.-Y.

    1982-01-01

    The throughput performance of a TDMA channel with finite buffer capacity for transmitting data messages is considered. Each station has limited message buffer capacity and has Poisson message arrivals. Message arrivals will be blocked if the buffers are congested. Using the embedded Markov chain model, the solution procedure for the limiting system-size probabilities is presented in a recursive fashion. Numerical examples are given to demonstrate the tradeoffs between the blocking probabilities and the buffer sizing strategy.

  6. Using nitrogen-15 to quantify vegetative buffer effectiveness for sequestering nitrogen in runoff.

    PubMed

    Bedard-Haughn, A; Tate, K W; van Kessel, C

    2004-01-01

    Previous studies have observed higher levels of soluble nutrients leaving vegetative buffers than entering them, suggesting that the buffers themselves are acting as a source rather than a sink by releasing previously stored nutrients. This study used 98 atom % (15)N-labeled KNO(3) at a rate of 5 kg ha(-1) to quantify buffer efficiency for sequestering new inputs of NO(-)(3)-N in an extensively grazed irrigated pasture system. Buffer treatments consisted of an 8-m buffer, a 16-m buffer, and a nonbuffered control. Regardless of the form of runoff N (NO(-)(3), NH(+)(4), or dissolved organic nitrogen [DON]), more (15)N was lost from the nonbuffered treatments than from the buffered treatments. The majority of the N attenuation was by vegetative uptake. Over the course of the study, the 8-m buffer decreased NO(-)(3)-(15)N load by 28% and the 16-m buffer decreased load by 42%. For NH(+)(4)-(15)N, the decrease was 34 and 48%, and for DON-(15)N, the decrease was 21 and 9%. Although the buffers were effective overall, the majority of the buffer impact occurred in the first four weeks after (15)N application, with the buffered plots attenuating nearly twice as much (15)N as the nonbuffered plots. For the remainder of the study, buffer effect was not as marked; there was a steady release of (15)N, particularly NO(-)(3)- and DON-(15)N, from the buffers into the runoff. This suggests that for buffers to be sustainable for N sequestration there is a need to manage buffer vegetation to maximize N demand and retention.

  7. The quantitation of buffering action II. Applications of the formal & general approach

    PubMed Central

    Schmitt, Bernhard M

    2005-01-01

    Background The paradigm of "buffering" originated in acid-base physiology, but was subsequently extended to other fields and is now used for a wide and diverse set of phenomena. In the preceding article, we have presented a formal and general approach to the quantitation of buffering action. Here, we use that buffering concept for a systematic treatment of selected classical and other buffering phenomena. Results H+ buffering by weak acids and "self-buffering" in pure water represent "conservative buffered systems" whose analysis reveals buffering properties that contrast in important aspects from classical textbook descriptions. The buffering of organ perfusion in the face of variable perfusion pressure (also termed "autoregulation") can be treated in terms of "non-conservative buffered systems", the general form of the concept. For the analysis of cytoplasmic Ca++ concentration transients (also termed "muffling"), we develop a related unit that is able to faithfully reflect the time-dependent quantitative aspect of buffering during the pre-steady state period. Steady-state buffering is shown to represent the limiting case of time-dependent muffling, namely for infinitely long time intervals and infinitely small perturbations. Finally, our buffering concept provides a stringent definition of "buffering" on the level of systems and control theory, resulting in four absolute ratio scales for control performance that are suited to measure disturbance rejection and setpoint tracking, and both their static and dynamic aspects. Conclusion Our concept of buffering provides a powerful mathematical tool for the quantitation of buffering action in all its appearances. PMID:15771784

  8. Buffer Loading and Chunking in Sequential Keypressing (Het Laden van de Motor Buffer Versus Het Gebruik van Motor Chunks bij Sequentieule Toetsdrukseries)

    DTIC Science & Technology

    1994-03-18

    chunking in sequential keypressing (Het laden van de motor buffer versus het gebruik van motor chunks bij sequentiele toetsdrukseries) W.B. Verwey 18 maart...1994, Rapport TM 1994 B-7 TNO Technische Menskunde’, Soesterberg MANAGEMENT UITTREKSEL Dit rapport beschrijft een experiment naar de effecten van...Menakunde. Korte samenvatting van: Buffer loading and chunking in sequential keypressing (Het laden van de motor buffer versus het gebruik van motor

  9. Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells.

    PubMed

    Nam, Joo-Youn; Kim, Hyun-Woo; Lim, Kyeong-Ho; Shin, Hang-Sik; Logan, Bruce E

    2010-01-15

    Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers are used in laboratory media, but the effects of these buffers and their inherent electrolyte conductivities have not been examined relative to current generation in MFCs. We investigated the effect of several common buffers (phosphate, MES, HEPES, and PIPES) on power production in single chambered MFCs compared to a non-buffered control. At the same concentrations the buffers produced different solution conductivities which resulted in different ohmic resistances and power densities. Increasing the solution conductivities to the same values using NaCl produced comparable power densities for all buffers. Very large increases in conductivity resulted in a rapid voltage drop at high current densities. Our results suggest that solution conductivity at a specific pH for each buffer is more important in MFC studies than the buffer itself given relatively constant pH conditions. Based on our analysis of internal resistance and a set neutral pH, phosphate and PIPES are the most useful buffers of those examined here because pH was maintained close to the pK(a) of the buffer, maximizing the ability of the buffer to contribute to increase current generation at high power densities.

  10. A clinical evaluation of the ability of the Dentobuff method to estimate buffer capacity of saliva.

    PubMed

    Wikner, S; Nedlich, U

    1985-01-01

    The power of a colourimetric method to estimate buffer capacity of saliva (Dentobuff) was compared with an electrometric method in 220 adults. The methods correlated well but Dentobuff frequently underestimated high buffer values which was considered to be of minor practical importance. Dentobuff identified groups with low, intermediate and high buffer capacity as good as the electrometric method.

  11. Impact of buffer type on streamside nutrient concentrations in Upper Big Walnut Creek, Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The identification and assessment of conservation practices continues to be important for the protection of natural resources. Buffers, also referred to as filter strips, buffer strips, riparian buffers, or vegetative filters are one of the most common types of conservation practice installed in the...

  12. Costs of Producing Biomass from Riparian Buffer Strips

    SciTech Connect

    Turhollow, A.

    2000-09-01

    Nutrient runoff from poultry litter applied to agricultural fields in the Delmarva Peninsula contributes to high nutrient loadings in Chesapeake Bay. One potential means of ameliorating this problem is the use of riparian buffer strips. Riparian buffer strips intercept overland flows of water, sediments, nutrients, and pollutants; and ground water flows of nutrients and pollutants. Costs are estimated for three biomass systems grown on buffer strips: willow planted at a density of 15,300 trees/ha (6200 trees/acre); poplar planted at a density of 1345 trees/ha (545 trees/acre); and switchgrass. These costs are estimated for five different scenarios: (1) total economic costs, where everything is costed [cash costs, noncash costs (e.g., depreciation), land rent, labor]; (2) costs with Conservation Reserve Program (CRP) payments (which pays 50% of establishment costs and an annual land rent); (3) costs with enhanced CRP payments (which pays 95% of establishment costs and an annual payment of approximately 170% of land rent for trees and 150% of land rent for grasses); (4) costs when buffer strips are required, but harvest of biomass is not required [costs borne by biomass are for yield enhancing activities (e.g., fertilization), harvest, and transport]; and (5) costs when buffer strips are required. and harvest of biomass is required to remove nutrients (costs borne by biomass are for yield enhancing activities and transport). CRP regulations would have to change to allow harvest. Delivered costs of willow, poplar, and switchgrass [including transportation costs of $0.38/GJ ($0.40/million Btu) for switchgrass and $0.57/GJ ($0.60/million Btu) for willow and poplar] at 11.2 dry Mg/ha-year (5 dry tons/acre-year) for the five cost scenarios listed above are [$/GJ ($million BIN)]: (1) 3.30-5.45 (3.45-5.75); (2) 2.30-3.80 (2.45-4.00); (3) 1.70-2.45 (1.80-2.60); (4) l-85-3.80 (1.95-4.05); and (5) 0.80-1.50 (0.85-1.60). At yields of 15.7 to 17.9 GJ/ha-year (7 to 8 dry tons

  13. Dynamic model and performance analysis of landing buffer for bionic locust mechanism

    NASA Astrophysics Data System (ADS)

    Chen, Dian-Sheng; Zhang, Zi-Qiang; Chen, Ke-Wei

    2016-06-01

    The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. Based on an experimental observation, the different modes of landing and buffering are determined, which include the different numbers of landing legs and different motion modes of legs in the buffering process. Then a bionic locust mechanism is established, and the springs are used to replace the leg muscles to achieve a buffering effect. To reveal the dynamic performance in the buffering process of the bionic locust mechanism, a dynamic model is established with different modes of landing and buffering. In particular, to analyze the buffering process conveniently, an equivalent vibration dynamic model of the bionic locust mechanism is proposed. Given the support forces of the ground to the leg links, which can be obtained from the dynamic model, the spring forces of the legs and the impact resistance of each leg are the important parameters affecting buffering performance, and evaluation principles for buffering performance are proposed according to the aforementioned parameters. Based on the dynamic model and these evaluation principles, the buffering performances are analyzed and compared in different modes of landing and buffering on a horizontal plane and an inclined plane. The results show that the mechanism with the ends of the legs sliding can obtain a better dynamic performance. This study offers primary theories for buffering dynamics and an evaluation of landing buffer performance, and it establishes a theoretical basis for studies and engineering applications.

  14. High Jc coated conductors with a simple buffer layer architecture

    NASA Astrophysics Data System (ADS)

    Gianni, L.; Baldini, A.; Bindi, M.; Gauzzi, A.; Rampino, S.; Zannella, S.

    2005-10-01

    We report on the in situ route for the continuous fabrication of YBCO coated conductors (CC) by thermal co-evaporation. CC architecture consists of YBCO film grown on biaxially textured Ni-alloys tapes buffered with a single layer of CeO2. The buffer layer deposition has been optimized by either e-beam or thermal evaporation using respectively ceria or metallic cerium. Best results have been obtained on CeO2 film, with a thickness less or equal than 100 nm, grown in a reducing atmosphere at 690 °C with a growth rate of 2.4 Å/s. The optimal samples exhibit a highly biaxial texture, as indicated by FWHM values in the range of 5-8° and 4-6° for respectively in- and out-of-plane orientations. The layers are characterized by an uniform and crack-free surface with an average roughness lower than 10 nm. SIMS analysis confirms the effectiveness of CeO2 buffer layer against Ni interdiffusion. This template allows to obtain YBCO films strong textured, with good superconductive properties. YBCO texture data are equivalent the CeO2 ones. Midpoint critical temperature, Tc, falls reproducibly in 87-88 K range, with transition widths ΔTc < 2-3 K. Critical current density, Jc, up to 2 MA/cm2 at 77 K in self-field, have been achieved in a meter long CC corresponding to Ic/width value of 130 A/cm-width. Uniformity and reproducibility of long CC properties are under optimization.

  15. Formation of monofunctional cisplatin-DNA adducts in carbonate buffer.

    PubMed

    Binter, Alexandra; Goodisman, Jerry; Dabrowiak, James C

    2006-07-01

    Carbonate in its various forms is an important component in blood and the cytosol. Since, under conditions that simulate therapy, carbonate reacts with cisplatin to form carbonato complexes, one of which is taken up and/or modified by the cell [C.R. Centerwall, J. Goodisman, D.J. Kerwood, J. Am. Chem. Soc., 127 (2005) 12768-12769], cisplatin-carbonato complexes may be important in the mechanism of action of cisplatin. In this report we study the binding of cisplatin to pBR322 DNA in two different buffers, using gel electrophoresis. In 23.8mM HEPES, N-(2-hydroxyethyl)-piperazine-N'-2-ethanesulfonic acid, 5mM NaCl, pH 7.4 buffer, cisplatin produces aquated species, which react with DNA to unwind supercoiled Form I DNA, increasing its mobility, and reducing the binding of ethidium to DNA. This behavior is consistent with the formation of the well-known intrastrand crosslink on DNA. In 23.8mM carbonate buffer, 5mM NaCl, pH 7.4, cisplatin forms carbonato species that produce DNA-adducts which do not significantly change supercoiling but enhance binding of ethidium to DNA. This behavior is consistent with the formation of a monofunctional cisplatin adduct on DNA. These results show that aquated cisplatin and carbonato complexes of cisplatin produce different types of lesions on DNA and they underscore the importance of carrying out binding studies with cisplatin and DNA using conditions that approximate those found in the cell.

  16. Buffer thermal energy storage for a solar Brayton engine

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    A study has been completed on the application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine. To aid in the study, a computer program was written for complete transient/stead-state Brayton cycle performance. The results indicated that thermal storage can afford a significant decrease in the number of engine shutdowns as compared to operating without thermal storage. However, the number of shutdowns does not continuously decrease as the storage material weight increases. In fact, there appears to be an optimum weight for minimizing the number of shutdowns.

  17. Generating soft shadows with a depth buffer algorithm

    NASA Technical Reports Server (NTRS)

    Brotman, L. S.; Badler, N. I.

    1984-01-01

    Computer-synthesized shadows used to appear with a sharp edge when cast onto a surface. At present the production of more realistic, soft shadows is considered. However, significant costs arise in connection with such a representation. The current investigation is concerned with a pragmatic approach, which combines an existing shadowing method with a popular visible surface rendering technique, called a 'depth buffer', to generate soft shadows resulting from light sources of finite extent. The considered method represents an extension of Crow's (1977) shadow volume algorithm.

  18. Conductive and robust nitride buffer layers on biaxially textured substrates

    DOEpatents

    Sankar, Sambasivan [Chicago, IL; Goyal, Amit [Knoxville, TN; Barnett, Scott A [Evanston, IL; Kim, Ilwon [Skokie, IL; Kroeger, Donald M [Knoxville, TN

    2009-03-31

    The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metals and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layer. In some embodiments the article further comprises electromagnetic devices which may have superconducting properties.

  19. Conductive and robust nitride buffer layers on biaxially textured substrates

    DOEpatents

    Sankar, Sambasivan; Goyal, Amit; Barnett, Scott A.; Kim, Ilwon; Kroeger, Donald M.

    2004-08-31

    The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metal and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layers. In some embodiments the article further comprises electromagnetic devices which may be super conducting properties.

  20. Alloys containing antimony as metamorphic buffer layer for device applications

    NASA Astrophysics Data System (ADS)

    Rodriguez, Benny Perez

    This work explores the stress/strain relaxation kinetics in metamorphic buffer layers of GaAs1-xSbx/GaAs (001) grown by molecular beam epitaxy. The real-time stress/strain evolution was obtained using an in situ multi-beam optical sensor measurement, and combined with detailed analysis from x-ray diffraction, transmission electron microscopy, and atomic force microscopy. Several distinct stages of the strain relaxation were observed during growth of GaAs1-xSbx constant composition buffer layers, which are separated into three main regimes: pseudomorphic growth, fast strain relaxation and saturation. Constant composition layers of GaAs0.5Sb0.5/GaAs initially relax elastically followed by the rapid nucleation of both 60° and pure edge dislocations. The saturation regime is distinguished by coalescence of small islands that appears to trigger the formation of threading dislocations. The strain relaxation profile for GaAs0.5Sb0.5, GaAs0.61Sb0.39, and In0.2Ga0.8As films were modeled using Dodson and Tsao's model of effective stress, with a new representation for elastic interactions of misfit dislocations. The model results agree with the experimental data and show that repulsive interaction of misfit dislocations is responsible for the large residual stress. Using this model, estimated line dislocation densities are in good agreement with the values obtained experimentally. This could have potential application in the design of metamorphic buffer layers because our observations are made in real time on individual growth, without the need of external characterization to measure the dislocation density. In addition, this model offers new insights in estimating the dislocation glide energy for simulation purposes. Linearly graded GaAs1-xSbx films resulted in a decreased Sb incorporation, higher residual stress, and bifurcation in the tilt of the sample. Less aggressive grading resulted in more uniform incorporation and lower residual stress. Step graded films resulted in

  1. A miniature biofuel cell operating in a physiological buffer.

    PubMed

    Mano, Nicolas; Mao, Fei; Heller, Adam

    2002-11-06

    A glucose-O2 biofuel cell, consisting only of two electrocatalyst coated 7-mum diameter, 2-cm long carbon fibers is reported. The cell operated continuously at 0.52 V at 37 degrees C in a physiological buffer solution for a week, producing 1.9 muW during the first and 1.0 muW during the last day, generating in the period 0.9 J of electrical energy while passing a charge of 1.7 C. If a similar dimension zinc fiber were utilized in a battery at 100% current efficiency, only 0.016 C would have been generated.

  2. Non-sticking of helium buffer gas to hydrocarbons

    NASA Astrophysics Data System (ADS)

    Croft, James F. E.; Bohn, John L.

    2015-03-01

    Lifetimes of complexes formed during helium-hydrocarbon collisions at low temperature are estimated for symmetric-top hydrocarbons. The lifetimes are obtained using a density-of-states approach. In general the lifetimes are less than 10-100 ns and are found to decrease with increasing hydrocarbon size. This suggests that clustering will not limit precision spectroscopy in helium-buffer-gas experiments. Lifetimes are computed for noble-gas benzene collisions and are found to be in reasonable agreement with lifetimes obtained from classical trajectories as reported by J. Cui et al. [J. Chem. Phys. 141, 164315 (2014), 10.1063/1.4898796].

  3. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    SciTech Connect

    Engel, Jesse H.; Surendranath, Yogesh; Alivisatos, Paul

    2013-07-20

    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  4. Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.

    PubMed

    Fortier, Julien; Truax, Benoit; Gagnon, Daniel; Lambert, France

    2015-05-01

    In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the

  5. Photo-induced wettability of TiO{sub 2} film with Au buffer layer

    SciTech Connect

    Purkayastha, Debarun Dhar; Sangani, L. D. Varma; Krishna, M. Ghanashyam; Madhurima, V.

    2014-04-24

    The effect of thickness of Au buffer layer (15-25 nm) between TiO{sub 2} film and substrate on the wettability of TiO{sub 2} films is reported. TiO{sub 2} films grown on Au buffer layer have a higher contact angle of 96-;100° as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven.

  6. Characterization of uronate dehydrogenases catalysing the initial step in an oxidative pathway

    PubMed Central

    Pick, André; Schmid, Jochen; Sieber, Volker

    2015-01-01

    Uronate dehydrogenases catalyse the oxidation of uronic acids to aldaric acids, which represent ‘top value-added chemicals’ that have the potential to substitute petroleum-derived chemicals. The identification and annotation of three uronate dehydrogenases derived from Fulvimarina pelagi HTCC2506, Streptomyces viridochromogenes DSM 40736 and Oceanicola granulosus DSM 15982 via sequence analysis is described. Characterization and comparison with two known uronate dehydrogenases in regard to substrate spectrum, catalytic activity and pH as well as temperature dependence was performed. The catalytic efficiency was investigated in two different buffer systems; potassium phosphate and Tris-HCl. In addition to the typical and well available substrates glucuronate and galacturonate also mannuronate as part of many structural polysaccharides were tested. The uronate dehydrogenase of Agrobacterium tumefaciens and Pseudomonas syringae showed catalytic dependency on the buffer system resulting in an increased Km especially for glucuronate in potassium phosphate compared with Tris-HCl buffer. Enzyme stability at 37°C of the different Udhs was in the order: P. syringae < S. viridochromogens < A. tumefaciens < F. pelagi < O. granulosus. All enzymes showed activity within a broad pH range from 7.0 to 9.5, only O. granulosus had a very narrow range around 7.0. PMID:25884328

  7. Grassed buffer strips as nitrate diffuse pollution remediation tools: management impact on the denitrification enzyme activity.

    PubMed

    Cors, M; Tychon, B

    2007-01-01

    The management of grassed buffer strips proved to be an efficient remediation technique in controlling nitrogen losses to surface water. In south Belgium, agri-environmental policies have encouraged farmers to seed buffer strips along rivers, in zones where the soil was previously devoted to agricultural production. We wanted to assess how important denitrification is in a buffer strip in comparison with a cropped field. The study investigated the denitrifiying enzyme activity (DEA) of two contiguous buffer strips with different management stories. The eastern part of the buffer strip was seeded in 1999. The western part of the buffer strip is a piece of crop field abandoned by the farmer 20 years ago and not managed for the last 10 years. This experimental study demonstrates that the denitrification enzyme activity in a riparian buffer strip is significantly higher than in the adjacent cropped field (3.67 and 2.12 mgNkg(-1)d(-1) respectively). The DEA was significantly different between the two buffer strips under comparison, assessing that the management of the buffer strips has a dominant effect on DEA. The old unmown buffer strip is potentially more efficient in the nitrate removal process than the 6-year-old seeded buffer strip.

  8. A wavelike buffer for introducing samples into autonomous capillary microfluidic devices

    NASA Astrophysics Data System (ADS)

    Li, Jingmin; Liang, Chao; Wang, Shuai; Guo, Lihua; Liu, Ziyang; Liu, Chong

    2017-01-01

    The microfluidic technique has gained attention due to its advantages in providing a rapid diagnostic result for on-site diagnosis and treatment. To obtain a quantitative and reproducible diagnostic result the fluid flow in the microfluidic device must be steady. However, a non-specific flow will always form due to the disturbances introduced during the sample injecting process. Here, a wavelike sample introduction buffer is presented. The buffer can change the longitudinal flow of the injected sample to a transverse flow, which will consume the kinetic energy and eliminate disturbances. By using the buffer, fluid flow within a microfluidic device can become steady. The effects of the buffer parameters on buffering performance have been studied. Results show that the buffering performance increases as the waved peak height and peak number decrease. This buffer has a simple structure. It requires no external power supplies or complicated fabrication process. It will be helpful in improving the diagnostic accuracy of microfluidic devices.

  9. Leakage effects in n-GaAs MESFET with n-GaAs buffer layer

    NASA Technical Reports Server (NTRS)

    Wang, Y. C.; Bahrami, M.

    1983-01-01

    Whereas improvement of the interface between the active layer and the buffer layer has been demonstrated, the leakage effects can be important if the buffer layer resistivity is not sufficiently high and/or the buffer layer thickness is not sufficiently small. It was found that two buffer leakage currents exist from the channel under the gate to the source and from drain to the channel in addition to the buffer leakage resistance between drain and source. It is shown that for a 1 micron gate-length n-GaAs MESFET, if the buffer layer resistivity is 12 OHM-CM and the buffer layer thickness h is 2 microns, the performance of the device degrades drastically. It is suggested that h should be below 2 microns.

  10. An assessment of buffer strips for improving damage tolerance of composite laminates at elevated temperature

    NASA Technical Reports Server (NTRS)

    Bigelow, C. A.

    1981-01-01

    Buffer strips greatly improve the damage tolerance of graphite/epoxy laminates loaded in tension. Graphite/polyimide buffer strip panels were made and tested to determine their residual strength at ambient and elevated (177 C) temperature. Each panel was cut in the center to represent damage. Panels were radiographed and crack-opening displacements were recorded to indicate fracture, fracture arrest, and the extent of damage in the buffer strip after arrest. All panels had the same buffer strip spacing and width. The buffer strip material was 0 deg S-glass/PMR-15. The buffer strips were made by replacing narrow strips of the 0 deg graphite plies with strips of the 0 deg S-glass on either a one-for-one or a two-for-one basis. Half of the panels were heated to 177 + or - 3 C before and during the testing. Elevated temperature did not alter the fracture behavior of the buffer configuration.

  11. Buffer layers on rolled nickel or copper as superconductor substrates

    DOEpatents

    Paranthaman, Mariappan; Lee, Dominic F.; Kroeger, Donald M.; Goyal, Amit

    2000-01-01

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled substrates of nickel and/or copper and their alloys for high current conductors, and more particularly buffer layer architectures such as Y.sub.2 O.sub.3 /Ni, YSZ/Y.sub.2 O.sub.3 /Ni, Yb.sub.2 O.sub.3 /Ni, Yb.sub.2 O.sub.3 /Y.sub.2 O.sub.3 /Ni, Yb.sub.2 O.sub.3 /CeO.sub.2 /Ni, RE.sub.2 O.sub.3 /Ni (RE=Rare Earth), and Yb.sub.2 O.sub.3 /YSZ/CeO.sub.2 /Ni, Y.sub.2 O.sub.3 /Cu, YSZ/Y.sub.2 O.sub.3 /Cu, Yb.sub.2 O.sub.3 /Cu, Yb.sub.2 O.sub.3 /Y.sub.2 O.sub.3 /Cu, Yb.sub.2 O.sub.3 /CeO.sub.2 /Cu, RE.sub.2 O.sub.3 /Cu, and Yb.sub.2 O.sub.3 /YSZ/CeO.sub.2 /Cu. Deposition methods include physical vapor deposition techniques which include electron-beam evaporation, rf magnetron sputtering, pulsed laser deposition, thermal evaporation, and solution precursor approach, which includes chemical vapor deposition, combustion CVD, metal-organic decomposition, sol-gel processing, and plasma spray.

  12. The Effects of Acetate Buffer Concentration on Lysozyme Solubility

    NASA Technical Reports Server (NTRS)

    Forsythe, Elizabeth L.; Pusey, Marc L.

    1996-01-01

    The micro-solubility column technique was employed to systematically investigate the effects of buffer concentration on tetragonal lysozyme solubility. While keeping the NaCl concentrations constant at 2%, 3%, 4%, 5% and 7%, and the pH at 4.0, we have studied the solubility of tetragonal lysozyme over an acetate buffer concentration range of 0.01M to 0.5M as a function of temperature. The lysozyme solubility decreased with increasing acetate concentration from 0.01M to 0.1M. This decrease may simply be due to the net increase in solvent ionic strength. Increasing the acetate concentration beyond 0.1M resulted in an increase in the lysozyme solubility, which reached a peak at - 0.3M acetate concentration. This increase was believed to be due to the increased binding of acetate to the anionic binding sites of lysozyme, preventing their occupation by chloride. In keeping with the previously observed reversal of the Hoffmeister series for effectiveness of anions in crystallizing lysozyme, acetate would be a less effective precipitant than chloride. Further increasing the acetate concentration beyond 0.3M resulted in a subsequent gradual decrease in the lysozyme solubility at all NaCl concentrations.

  13. Equilibrium Studies of Dibutyltin(IV)-Zwitterionic Buffer Complexation.

    PubMed

    El-Gahami, M A; Albishri, H M

    2013-01-01

    Equilibrium studies in aqueous solution are reported for dibutyltin(IV) (DBT) complexes of the zwitterionic buffers "Good's buffers" Mes and Mops. Stoichiometric and formation constants of the complexes formed were determined at different temperatures and ionic strength 0.1 mol·L(-1) NaNO3. The results show that the best fit of the titration curves were obtained when the complexes ML, MLH-1, MLH-2 and MLH-3 were considered beside the hydrolysis product of the dibutyltin(IV) cation. The thermodynamic parameters ΔH(o), ΔS(o) and ΔG(o) calculated from the temperature dependence of the formation constant of the dibutyltin(IV) complexes with 2-(N-morpholino)ethanesulfonic acid (Mes) and 3-(N-mor-pholino)-propanesulfonic acid (Mops) were investigated. The effect of dioxane as a solvent on the formation constants of DBT-Mes and DBT-Mops complexes decrease linearly with the increase of dioxane proportion in the medium. The concentration distribution of the various complexes species was evaluated as a function of pH.

  14. Intracellular calcium buffering declines in aging adrenergic nerves.

    PubMed

    Tsai, H; Hewitt, C W; Buchholz, J N; Duckles, S P

    1997-01-01

    Stimulation-evoked norepinephrine release from rat tail artery adrenergic nerves increased with advancing age in the Fischer-344 rat when function of norepinephrine uptake mechanisms and prejunctional alpha-2 adrenoceptors were blocked. When calcium channels were bypassed with the ionophore, ionomycin (4 microM), norepinephrine release from aged nerves (20 months) was still elevated as compared to 6-month-old nerves. Norepinephrine release stimulated by high K+ was also higher in 20-month nerves. The intracellular calcium chelator, 1,2 bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetomethylester (BAPTA/AM), was used to determine whether age-related increases in norepinephrine release could be reversed with the addition of an artificial intracellular calcium buffer. Exposure to BAPTA/AM decreased stimulation-evoked norepinephrine release in both old and young tail arteries; however, the effect was significantly greater in older arteries. When mitochondrial calcium uptake was compromised using the uncoupler of mitochondrial oxidative phosphorylation, dinitrophenol, BAPTA caused a further decrease in stimulation-evoked norepinephrine release in 20-month tail arteries with much less effect in 6-month-old nerves. These results suggest that intracellular calcium buffering is less efficient in older nerves.

  15. Buffer capacity, ecosystem feedbacks, and seawater chemistry under global change

    NASA Astrophysics Data System (ADS)

    Jury, C. P.; Thomas, F. I.; Atkinson, M. J.; Jokiel, P. L.; Onuma, M. A.; Kaku, N.; Toonen, R. J.

    2013-12-01

    Ocean acidification (OA) results in reduced seawater pH and aragonite saturation state (Ωarag), but also reduced seawater buffer capacity. As buffer capacity decreases, diel variation in seawater chemistry increases. However, a variety of ecosystem feedbacks can modulate changes in both average seawater chemistry and diel seawater chemistry variation. Here we model these effects for a coastal, reef flat ecosystem. We show that an increase in offshore pCO2 and temperature (to 900 μatm and +3°C) can increase diel pH variation by as much as a factor of 2.5 and can increase diel pCO2 variation by a factor of 4.6, depending on ecosystem feedbacks and seawater residence time. Importantly, these effects are different between day and night. With increasing seawater residence time and increasing feedback intensity, daytime seawater chemistry becomes more similar to present-day conditions while nighttime seawater chemistry becomes less similar to present-day conditions. Better constraining ecosystem feedbacks under global change will improve projections of coastal water chemistry, but this study shows the importance of considering changes in both average carbonate chemistry and diel chemistry variation for organisms and ecosystems. Further, we will discuss our recent work examining the effects of diel seawater chemistry variation on coral calcification rates.

  16. Stability of glufosfamide in phosphate buffers and in biological samples.

    PubMed

    Sun, Yuming; Chen, Xiaoyan; Xu, Haiyan; Guan, Zhongmin; Zhong, Dafang

    2006-03-07

    Glufosfamide is a new, potential chemotherapeutic agent currently under investigation. Stability of glufosfamide was investigated in sodium phosphate buffers with different pH and temperature and in biological samples. Glufosfamide and isophosphamide mustard were quantified simultaneously using a liquid chromatography-ion trap mass spectrometric method; precision and accuracy were within 15% for each analyte. Glufosfamide was stable in neutral buffers, but decomposed to form isophosphoramide mustard under acidic and basic conditions, which was pH- and temperature-dependent. The stability of glufosfamide varied in different biological samples. Results indicated that glufosfamide was unstable in some biological samples, such as the small intestine, smooth muscles, pancreas and urine, especially in the small intestine homogenate, with a half-life of 1.1 h. But the pH (<8) and beta-glucosidase of the tissue homogenate was found to have negligible contribution to the degradation of glufosfamide. The enzymatic inhibition experiment with the specific inhibitor, saccharo-1,4-lactone, demonstrated that it was glucuronidase that resulted in the degradation of glufosfamide in small intestine homogenate. Methanol was recommended to be used to homogenize the tissue in an ice water bath, and the container for urine collection should also be maintained in an ice water bath, and all the biological samples collected should be preserved in frozen condition until analysis.

  17. Transient response of a thermal buffer: a study for ISABELLE

    SciTech Connect

    Schneider. W.J.

    1981-01-01

    Operation of the superconducting magnets in ISABELLE may necessitate rapid cooldown and warmup from ambient (300K) to liquid helium temperature (3K) to meet the requirements of the experimental program. Similarly, unprogrammed temperature excursions can also occur due to operator error or equipment malfunction. The coal bore tube of the magnets has a small mass relative to the more massive iron laminations and the stainless steel support tube. In addition the magnet coil, in thermal contact with the cold bore tube, has excellent heat transfer to the helium flowing through it compared to the iron mass. These two factors, mass and heat transfer, dictate that the cold bore tube will follow the temperature of the coolant more closely than the iron and hence substantial temperature gradients can exist. If the temperature difference between the coolant and the iron in the magnet exceeds 44K stress failure may occur to either the cold bore tube or the magnet dewar end cap. To preclude such failures from occuring at least two options are available. One method is to modify the magnet design by introducing flexibility between the bore tube and the end plate. Another is to introduce an insensitive thermal mass or buffer as has been suggested by Shutt, at the inlet of a sextant ahead of the first magnets. This paper describes the latter method, the design and transient response of a buffer during cooldown.

  18. Parental care buffers against inbreeding depression in burying beetles

    PubMed Central

    Pilakouta, Natalie; Jamieson, Seonaidh; Moorad, Jacob A.; Smiseth, Per T.

    2015-01-01

    When relatives mate, their inbred offspring often suffer a reduction in fitness-related traits known as “inbreeding depression.” There is mounting evidence that inbreeding depression can be exacerbated by environmental stresses such as starvation, predation, parasitism, and competition. Parental care may play an important role as a buffer against inbreeding depression in the offspring by alleviating these environmental stresses. Here, we examine the effect of parental care on the fitness costs of inbreeding in the burying beetle Nicrophorus vespilloides, an insect with facultative parental care. We used a 2 × 2 factorial design with the following factors: (i) the presence or absence of a caring female parent during larval development and (ii) inbred or outbred offspring. We examined the joint influence of maternal care and inbreeding status on fitness-related offspring traits to test the hypothesis that maternal care improves the performance of inbred offspring more than that of outbred offspring. Indeed, the female's presence led to a higher increase in larval survival in inbred than in outbred broods. Receiving care at the larval stage also increased the lifespan of inbred but not outbred adults, suggesting that the beneficial buffering effects of maternal care can persist long after the offspring have become independent. Our results show that parental care has the potential to moderate the severity of inbreeding depression, which in turn may favor inbreeding tolerance and influence the evolution of mating systems and other inbreeding-avoidance mechanisms. PMID:26080412

  19. Electrochemical behaviour of silver in borate buffer solutions

    NASA Astrophysics Data System (ADS)

    Zaky, Ayman M.; Assaf, Fawzi H.; Abd El Rehim, Sayed S.; Mohamed, Basheer M.

    2004-01-01

    The electrochemical behaviour of Ag in aqueous 0.15 M borax and 0.15 M boric acid buffer solution was studied under various conditions using cyclic voltammetry and potentiostatic techniques. It was found that the anodic polarization curve of Ag in borate buffer solution was characterized by the appearance of two potential regions, active and passive, prior to the oxygen evolution reaction. The active potential region was characterized by the appearance of three anodic peaks, the first two peaks A 1 and A 2 correspond to the oxidation of Ag and formation of [Ag(OH) 2] - soluble compound and a passive film of Ag 2O on the electrode surface. The third anodic peak corresponds to the conversion of both [Ag(OH) 2] - and Ag 2O to Ag 2O 2. X-ray diffraction patterns confirmed the existence of Ag 2O and Ag 2O 2 passive layers on the electrode surface potentiodynamically polarized up to 800 mV. Potentiostatic current transient measurements showed that the formation of Ag 2O and Ag 2O 2 involves a nucleation and growth mechanism under diffusion control.

  20. The Buffer Diagnostic Prototype: A fault isolation application using CLIPS

    NASA Technical Reports Server (NTRS)

    Porter, Ken

    1994-01-01

    This paper describes problem domain characteristics and development experiences from using CLIPS 6.0 in a proof-of-concept troubleshooting application called the Buffer Diagnostic Prototype. The problem domain is a large digital communications subsystems called the real-time network (RTN), which was designed to upgrade the launch processing system used for shuttle support at KSC. The RTN enables up to 255 computers to share 50,000 data points with millisecond response times. The RTN's extensive built-in test capability but lack of any automatic fault isolation capability presents a unique opportunity for a diagnostic expert system application. The Buffer Diagnostic Prototype addresses RTN diagnosis with a multiple strategy approach. A novel technique called 'faulty causality' employs inexact qualitative models to process test results. Experimental knowledge provides a capability to recognize symptom-fault associations. The implementation utilizes rule-based and procedural programming techniques, including a goal-directed control structure and simple text-based generic user interface that may be reusable for other rapid prototyping applications. Although limited in scope, this project demonstrates a diagnostic approach that may be adapted to troubleshoot a broad range of equipment.

  1. Parental care buffers against inbreeding depression in burying beetles.

    PubMed

    Pilakouta, Natalie; Jamieson, Seonaidh; Moorad, Jacob A; Smiseth, Per T

    2015-06-30

    When relatives mate, their inbred offspring often suffer a reduction in fitness-related traits known as "inbreeding depression." There is mounting evidence that inbreeding depression can be exacerbated by environmental stresses such as starvation, predation, parasitism, and competition. Parental care may play an important role as a buffer against inbreeding depression in the offspring by alleviating these environmental stresses. Here, we examine the effect of parental care on the fitness costs of inbreeding in the burying beetle Nicrophorus vespilloides, an insect with facultative parental care. We used a 2 × 2 factorial design with the following factors: (i) the presence or absence of a caring female parent during larval development and (ii) inbred or outbred offspring. We examined the joint influence of maternal care and inbreeding status on fitness-related offspring traits to test the hypothesis that maternal care improves the performance of inbred offspring more than that of outbred offspring. Indeed, the female's presence led to a higher increase in larval survival in inbred than in outbred broods. Receiving care at the larval stage also increased the lifespan of inbred but not outbred adults, suggesting that the beneficial buffering effects of maternal care can persist long after the offspring have become independent. Our results show that parental care has the potential to moderate the severity of inbreeding depression, which in turn may favor inbreeding tolerance and influence the evolution of mating systems and other inbreeding-avoidance mechanisms.

  2. Buffer Gas Cooled Molecule Source for Cpmmw Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Grimes, David; Barnum, Timothy J.; Klein, Ethan; Field, Robert W.

    2014-06-01

    We have built a new molecular beam source that implements 20 K Neon buffer gas cooling for the study of the spectra of small molecules. In particular, laser ablation of BaF2 pellets has been optimized to produce a molecular beam of BaF with a number density more than 100 times greater than what we have previously obtained from a typical Smalley-type photoablation supersonic beam source. Moreover, the forward beam velocity of 150 m/s in our apparatus represents an approximate 10-fold reduction, improving spectroscopic resolution from 500 kHz to better than 50 kHz at 100 GHz in a chirped-pulse millimeter-wave experiment in which resolution is limited by Doppler broadening. Novel improvements in our buffer gas source and advantages for CPmmW spectroscopy studies will be discussed. We thank David Patterson, John Barry, John Doyle, and David DeMille for help in the design of our source.

  3. Matching phosphate and maleate buffer systems for dissolution of weak acids: Equivalence in terms of buffer capacity of bulk solution or surface pH?

    PubMed

    Cristofoletti, Rodrigo; Dressman, Jennifer B

    2016-06-01

    The development of in vitro dissolution tests able to anticipate the in vivo fate of drug products has challenged pharmaceutical scientists over time, especially in the case of ionizable compounds. In the seminal model proposed by Mooney et al. thirty-five years ago, the pH at the solid-liquid interface (pH0) was identified as a key parameter in predicting dissolution rate. In the current work it is demonstrated that the in vitro dissolution of the weak acid ibuprofen in maleate and phosphate buffer systems is a function of the pH0, which in turn is affected by properties of the drug and the medium. The reported pH0 for ibuprofen dissolution in bicarbonate buffer, the predominant buffer species in the human small intestine under fasting conditions, can be achieved by reducing the phosphate buffer concentration to 5.0mM or the maleate buffer concentration to 2.2mM. Using this approach to identify the appropriate buffer/buffer capacity combination for in vitro experiments in FaSSIF-type media, it would be possible to increase the physiological relevance of this important biopharmaceutics tool. However, the necessity of monitoring and adjusting the bulk pH during the experiments carried out in 5.0mM phosphate or 2.2mM maleate buffers must also be taken into consideration.

  4. Wheeler County Riparian Buffers; 2003-2004 Annual Report.

    SciTech Connect

    Homer, Will

    2006-01-01

    Number of Contacts Made--I have contacted 35 landowners in Wheeler County. Of the 35 contacts 12 have resulted in meeting on their property to discuss available options. Included an article in the Annual Report and Wheeler SWCD newsletter mailed to 550 landowners. Contacts are primarily through networking with others here in the office as well as working closely with the NRCS office. Number of Contracts Negotiated--This Project has produced five riparian buffers within the past contract year. Each has greater meaning to the landowner than simply a buffer. In most cases the buffer is providing the landowner with improved grazing management and/or more reliable water source for livestock. Landowners also feel the enhanced wildlife habitat is a bonus to the program. Other Accomplishments--I took part in the John Day Subbasin Planning process and was able to offer assistance into the inventory items related to Wheeler County. I was often the only local representative able to attend the meetings. I assisted the Wheeler SWCD in writing a successful OWEB grant to remove 110 acres of junipers for watershed restoration, range rehabilitation, and economic development. One partner in the project is a manufacturer that uses juniper as their primary construction material. The goal is to create a pilot project that may grow into a self sustaining industry within the county. I also assisted in writing a small grant to improve water usage in the Muddy Creek watershed. I assisted with the Pine Creek Conservation Area ''Twilight Tour'' as well as the Wheeler SWCD ''Annual Meeting and Dinner''. Both events were successful in getting information out about our riparian buffer program. Facilitate office training and utilization of advanced GIS technology and mapping. Problems Encountered During Contract Year--The NRCS Cultural Resources Review process has ground to a halt. It is takes 6 months to get initial results from the Portland offices. Nearly all requests require site surveys

  5. Activation of a Ca-bentonite as buffer material

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Hsing; Chen, Wen-Chuan

    2016-04-01

    Swelling behavior is an important criterion in achieving the low-permeability sealing function of buffer material. A potential buffer material may be used for radioactive waste repository in Taiwan is a locally available clayey material known as Zhisin clay, which has been identified as a Ca-bentonite. Due to its Ca-based origin, Zhisin was found to exhibit swelling capacity much lower than that of Na-bentonite. To enhance the swelling potential of Zhisin clay, a cation exchange process by addition of Na2CO3 powder was introduced in this paper. The addition of Na2CO3 reagent to Zhisin clay, in a liquid phase, caused the precipitation of CaCO3 and thereby induced a replacement of Ca2+ ions by Na+ ions on the surface of bentonite. Characterization test conducted on Zhisin clay includes chemical analysis, cation exchange capacity, X-ray diffraction, and thermogravimetry (TG). Free-swelling test apparatus was developed according to International Society of Rock Mechanics recommendations. A series of free-swelling tests were conducted on untreated and activated specimens to characterize the effect of activation on the swelling capacity of Zhisin clay. Efforts were made to determine an optimum dosage for the activation, and to evaluate the aging effect. Also, the activated material was evaluated for its stability in various hydrothermal conditions for potential applications as buffer material in a repository. Experimental results show that Na2CO3-activated Zhisin clay is superior in swelling potential to untreated Zhisin clay. Also, there exists an optimum amount of activator in terms of improvements in the swelling capacity. A distinct time-swell relationship was discovered for activated Zhisin clay. The corresponding mechanism refers to exchange of cations and breakdown of quasi-crystal, which results in ion exchange hysteresis of Ca-bentonite. Due to the ion exchange hysteresis, activated bentonite shows a post-rise time-swell relationship different than the sigmoid

  6. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    PubMed

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions.

  7. Buffered lidocaine and bupivacaine mixture - the ideal local anesthetic solution?

    PubMed

    Best, Corliss A; Best, Alyssa A; Best, Timothy J; Hamilton, Danielle A

    2015-01-01

    The use of injectable local anesthetic solutions to facilitate pain-free surgery is an integral component of many procedures performed by the plastic surgeon. In many instances, a solution that has both rapid onset and prolonged duration of analgesia is optimal. A combination of lidocaine and bupivacaine, plain or with epinephrine, is readily available in most Canadian health care settings where such procedures are performed, and fulfills these criteria. However, commercially available solutions of both medications are acidic and cause a burning sensation on injection. Buffering to neutral pH with sodium bicarbonate is a practical method to mitigate the burning sensation, and has the added benefit of increasing the fraction of nonionized lipid soluble drug available. The authors report on the proportions of the three drugs to yield a neutral pH, and the results of an initial survey regarding the use of the combined solution with epinephrine in hand surgery.

  8. A high speed buffer for LV data acquisition

    NASA Technical Reports Server (NTRS)

    Cavone, Angelo A.; Sterlina, Patrick S.; Clemmons, James I., Jr.; Meyers, James F.

    1987-01-01

    The laser velocimeter (autocovariance) buffer interface is a data acquisition subsystem designed specifically for the acquisition of data from a laser velocimeter. The subsystem acquires data from up to six laser velocimeter components in parallel, measures the times between successive data points for each of the components, establishes and maintains a coincident condition between any two or three components, and acquires data from other instrumentation systems simultaneously with the laser velocimeter data points. The subsystem is designed to control the entire data acquisition process based on initial setup parameters obtained from a host computer and to be independent of the computer during the acquisition. On completion of the acquisition cycle, the interface transfers the contents of its memory to the host under direction of the host via a single 16-bit parallel DMA channel.

  9. High-precision buffer circuit for suppression of regenerative oscillation

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Hare, David A.; Tcheng, Ping

    1995-01-01

    Precision analog signal conditioning electronics have been developed for wind tunnel model attitude inertial sensors. This application requires low-noise, stable, microvolt-level DC performance and a high-precision buffered output. Capacitive loading of the operational amplifier output stages due to the wind tunnel analog signal distribution facilities caused regenerative oscillation and consequent rectification bias errors. Oscillation suppression techniques commonly used in audio applications were inadequate to maintain the performance requirements for the measurement of attitude for wind tunnel models. Feedback control theory is applied to develop a suppression technique based on a known compensation (snubber) circuit, which provides superior oscillation suppression with high output isolation and preserves the low-noise low-offset performance of the signal conditioning electronics. A practical design technique is developed to select the parameters for the compensation circuit to suppress regenerative oscillation occurring when typical shielded cable loads are driven.

  10. A buffer gas cooled beam of barium monohydride

    NASA Astrophysics Data System (ADS)

    Iwata, Geoffrey; Tarallo, Marco; Zelevinsky, Tanya

    2016-05-01

    Significant advances in direct laser cooling of diatomic molecules have opened up a wide array of molecular species to precision studies spanning many-body physics, quantum collisions and ultracold dissociation. We present a cryogenic beam source of barium monohydride (BaH), and study laser ablation of solid precursor targets as well as helium buffer gas cooling dynamics. Additionally, we cover progress towards a molecular magneto-optical trap, with spectroscopic studies of relevant cooling transitions in the B2 Σ <--X2 Σ manifold in laser ablated molecules, including resolution of hyperfine structure and precision measurements of the vibrational Frank-Condon factors. Finally, we examine the feasibility of photo dissociation of trapped BaH molecules to yield optically accessible samples of ultracold hydrogen.

  11. How much will evolution buffer changes in climate?

    NASA Astrophysics Data System (ADS)

    Franks, S. J.

    2007-12-01

    Current climate change is altering the phenology, or seasonal timing of reproduction and other life-history events, of many species. There is now evidence that at least some of these changes in phenology represent genetically- based evolution. Evolution may thus potentially serve as a buffer, allowing species to adapt to changes in climatic conditions. However, there are many constraints to evolution, including lack of genetic variation, antagonistic trait correlations, and physiological and developmental constraints. Furthermore, if changes in climate are extremely rapid and severe, many species may experience extinction rather than rapid evolution. I present recent empirical evidence for evolution following changes in climate, examine constraints to evolution, and ask if evolution can keep pace with rapid climate change. The empirical work focuses on the species Brassica rapa, which I show evolved earlier flowering time following several years of drought in Southern California.

  12. Affirmation of personal values buffers neuroendocrine and psychological stress responses.

    PubMed

    Creswell, J David; Welch, William T; Taylor, Shelley E; Sherman, David K; Gruenewald, Tara L; Mann, Traci

    2005-11-01

    Stress is implicated in the development and progression of a broad array of mental and physical health disorders. Theory and research on the self suggest that self-affirming activities may buffer these adverse effects. This study experimentally investigated whether affirmations of personal values attenuate physiological and psychological stress responses. Eighty-five participants completed either a value-affirmation task or a control task prior to participating in a laboratory stress challenge. Participants who affirmed their values had significantly lower cortisol responses to stress, compared with control participants. Dispositional self-resources (e.g., trait self-esteem and optimism) moderated the relation between value affirmation and psychological stress responses, such that participants who had high self-resources and had affirmed personal values reported the least stress. These findings suggest that reflecting on personal values can keep neuroendocrine and psychological responses to stress at low levels. Implications for research on the self, stress processes, health, and interventions are discussed.

  13. Superconducting composite with multilayer patterns and multiple buffer layers

    DOEpatents

    Wu, X.D.; Muenchausen, R.E.

    1993-10-12

    An article of manufacture is described including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superconductor. 5 figures.

  14. Reaction of Thymidine with Hypobromous Acid in Phosphate Buffer.

    PubMed

    Suzuki, Toshinori; Kitabatake, Akihiko; Koide, Yuki

    2016-01-01

    When thymidine was treated with hypobromous acid (HOBr) in 100 mM phosphate buffer at pH 7.2, two major product peaks appeared in the HPLC chromatogram. The products in each peak were identified by NMR and MS as two isomers of 5-hydroxy-5,6-dihydrothymidine-6-phosphate (a novel compound) and two isomers of 5,6-dihydroxy-5,6-dihydrothymidine (thymidine glycol) with comparable yields. 5-Hydroxy-5,6-dihydrothymidine-6-phosphate was relatively stable, and decomposed with a half-life of 32 h at pH 7.2 and 37°C generating thymidine glycol. The results suggest that 5-hydroxy-5,6-dihydrothymidine-6-phosphate in addition to thymidine glycol may have importance for mutagenesis by the reaction of HOBr with thymine residues in nucleotides and DNA.

  15. A Reversible Photoacid Functioning in PBS Buffer under Visible Light.

    PubMed

    Abeyrathna, Nawodi; Liao, Yi

    2015-09-09

    A metastable-state photoacid that can reversibly release a proton in PBS buffer (pH = 7.4) under visible light is reported. The design is based on the dual acid-base property and tautomerization of indazole. The quantum yield was as high as 0.73, and moderate light intensity (10(2) μmol·m(2)·s(-1)) is sufficient for the photoreaction. Reversible pH change of 1.7 units was demonstrated using a 0.1 mM aqueous solution. This type of photoacid is promising for control of proton-transfer processes in physiological conditions and may find applications in biomedical areas.

  16. Formation of buffer-gas-trap based positron beams

    SciTech Connect

    Natisin, M. R. Danielson, J. R. Surko, C. M.

    2015-03-15

    Presented here are experimental measurements, analytic expressions, and simulation results for pulsed, magnetically guided positron beams formed using a Penning-Malmberg style buffer gas trap. In the relevant limit, particle motion can be separated into motion along the magnetic field and gyro-motion in the plane perpendicular to the field. Analytic expressions are developed which describe the evolution of the beam energy distributions, both parallel and perpendicular to the magnetic field, as the beam propagates through regions of varying magnetic field. Simulations of the beam formation process are presented, with the parameters chosen to accurately replicate experimental conditions. The initial conditions and ejection parameters are varied systematically in both experiment and simulation, allowing the relevant processes involved in beam formation to be explored. These studies provide new insights into the underlying physics, including significant adiabatic cooling, due to the time-dependent beam-formation potential. Methods to improve the beam energy and temporal resolution are discussed.

  17. Proposal for Alzheimer's diagnosis using molecular buffer and bus network.

    PubMed

    Mitatha, S; Moongfangklang, N; Jalil, M A; Suwanpayak, N; Saktioto, T; Ali, J; Yupapin, P P

    2011-01-01

    A novel design of an optical trapping tool for tangle protein (tau tangles, β-amyloid plaques) and molecular motor storage and delivery using a PANDA ring resonator is proposed. The optical vortices can be generated and controlled to form the trapping tools in the same way as the optical tweezers. In theory, the trapping force is formed by the combination between the gradient field and scattering photons, and is reviewed. By using the intense optical vortices generated within the PANDA ring resonator, the required molecular volumes can be trapped and moved dynamically within the molecular buffer and bus network. The tangle protein and molecular motor can transport and connect to the required destinations, enabling availability for Alzheimer's diagnosis.

  18. ACCURATE CHEMICAL MASTER EQUATION SOLUTION USING MULTI-FINITE BUFFERS

    PubMed Central

    Cao, Youfang; Terebus, Anna; Liang, Jie

    2016-01-01

    The discrete chemical master equation (dCME) provides a fundamental framework for studying stochasticity in mesoscopic networks. Because of the multi-scale nature of many networks where reaction rates have large disparity, directly solving dCMEs is intractable due to the exploding size of the state space. It is important to truncate the state space effectively with quantified errors, so accurate solutions can be computed. It is also important to know if all major probabilistic peaks have been computed. Here we introduce the Accurate CME (ACME) algorithm for obtaining direct solutions to dCMEs. With multi-finite buffers for reducing the state space by O(n!), exact steady-state and time-evolving network probability landscapes can be computed. We further describe a theoretical framework of aggregating microstates into a smaller number of macrostates by decomposing a network into independent aggregated birth and death processes, and give an a priori method for rapidly determining steady-state truncation errors. The maximal sizes of the finite buffers for a given error tolerance can also be pre-computed without costly trial solutions of dCMEs. We show exactly computed probability landscapes of three multi-scale networks, namely, a 6-node toggle switch, 11-node phage-lambda epigenetic circuit, and 16-node MAPK cascade network, the latter two with no known solutions. We also show how probabilities of rare events can be computed from first-passage times, another class of unsolved problems challenging for simulation-based techniques due to large separations in time scales. Overall, the ACME method enables accurate and efficient solutions of the dCME for a large class of networks. PMID:27761104

  19. Monte Carlo modeling and optimization of buffer gas positron traps

    NASA Astrophysics Data System (ADS)

    Marjanović, Srđan; Petrović, Zoran Lj

    2017-02-01

    Buffer gas positron traps have been used for over two decades as the prime source of slow positrons enabling a wide range of experiments. While their performance has been well understood through empirical studies, no theoretical attempt has been made to quantitatively describe their operation. In this paper we apply standard models as developed for physics of low temperature collision dominated plasmas, or physics of swarms to model basic performance and principles of operation of gas filled positron traps. The Monte Carlo model is equipped with the best available set of cross sections that were mostly derived experimentally by using the same type of traps that are being studied. Our model represents in realistic geometry and fields the development of the positron ensemble from the initial beam provided by the solid neon moderator through voltage drops between the stages of the trap and through different pressures of the buffer gas. The first two stages employ excitation of N2 with acceleration of the order of 10 eV so that the trap operates under conditions when excitation of the nitrogen reduces the energy of the initial beam to trap the positrons without giving them a chance to become annihilated following positronium formation. The energy distribution function develops from the assumed distribution leaving the moderator, it is accelerated by the voltage drops and forms beams at several distinct energies. In final stages the low energy loss collisions (vibrational excitation of CF4 and rotational excitation of N2) control the approach of the distribution function to a Maxwellian at room temperature but multiple non-Maxwellian groups persist throughout most of the thermalization. Optimization of the efficiency of the trap may be achieved by changing the pressure and voltage drops and also by selecting to operate in a two stage mode. The model allows quantitative comparisons and test of optimization as well as development of other properties.

  20. ACCURATE CHEMICAL MASTER EQUATION SOLUTION USING MULTI-FINITE BUFFERS.

    PubMed

    Cao, Youfang; Terebus, Anna; Liang, Jie

    2016-01-01

    The discrete chemical master equation (dCME) provides a fundamental framework for studying stochasticity in mesoscopic networks. Because of the multi-scale nature of many networks where reaction rates have large disparity, directly solving dCMEs is intractable due to the exploding size of the state space. It is important to truncate the state space effectively with quantified errors, so accurate solutions can be computed. It is also important to know if all major probabilistic peaks have been computed. Here we introduce the Accurate CME (ACME) algorithm for obtaining direct solutions to dCMEs. With multi-finite buffers for reducing the state space by O(n!), exact steady-state and time-evolving network probability landscapes can be computed. We further describe a theoretical framework of aggregating microstates into a smaller number of macrostates by decomposing a network into independent aggregated birth and death processes, and give an a priori method for rapidly determining steady-state truncation errors. The maximal sizes of the finite buffers for a given error tolerance can also be pre-computed without costly trial solutions of dCMEs. We show exactly computed probability landscapes of three multi-scale networks, namely, a 6-node toggle switch, 11-node phage-lambda epigenetic circuit, and 16-node MAPK cascade network, the latter two with no known solutions. We also show how probabilities of rare events can be computed from first-passage times, another class of unsolved problems challenging for simulation-based techniques due to large separations in time scales. Overall, the ACME method enables accurate and efficient solutions of the dCME for a large class of networks.

  1. Three-Dimensional Frame Buffers For Interactive Analysis Of Three-Dimensional Data

    NASA Astrophysics Data System (ADS)

    Hunter, Gregory M.

    1986-02-01

    Two-dimensional data such as photos, x-rays, various types of satellite images, sonar, radar, seismic plots, etc., in many cases must be analyzed using frame buffers for purposes of medical diagnoses, crop estimates, mineral exploration, and so forth. In many cases the same types of sensors used to gather such samples in two dimensions can gather 3D data for even more effective analysis. Just as 2D arrays of data can be analyzed using frame buffers, three-dimensional data can be analyzed using SOLIDS-BUFFER memories. Image processors deal with samples from two-dimensional arrays and are based on frame buffers. The SOLIDS PROCESSOR system deals with samples from a three-dimensional volume, or solid, and is based on a 3D frame buffer. This paper focuses upon the SOLIDS-BUFFER system as used in the INSIGHT SOLIDS-PROCESSOR system from Phoenix Data Systems.

  2. Dynamically-allocated multi-queue buffers for VLSI communication switches

    NASA Technical Reports Server (NTRS)

    Tamir, Yuval; Frazier, Gregory L.

    1992-01-01

    Several buffer structures are discussed and compared in terms of implementation complexity, interswitch handshaking requirements, and their ability to deal with variations in traffic patterns and message lengths. A new design of buffers is presented that provide non-FIFO message handling and efficient storage allocation for variable size packets using linked lists managed by a simple on-chip controller. The new buffer design is evaluated by comparing it to several alternative designs in the context of a multistage interconnection network. The present modeling and simulations show that the new buffer outperforms alternative buffers and can thus be used to improve the performance of a wide variety of systems currently using less efficient buffers.

  3. Factors associated with salivary buffering capacity in young adults in Stockholm, Sweden.

    PubMed

    Wikner, S; Söder, P O

    1994-02-01

    The buffering capacity and flow rate of stimulated whole saliva were assessed in 150 persons, 20-24 yr of age. The associations were assessed between the buffer value and the flow rate, some dietary factors, tobacco habits, use of oral contraceptives, and some demographic variables. The results demonstrate that a low flow rate may predict a low buffer value but not a high value. Flow rate accounted for the largest part of the buffering variation but morning and afternoon saliva sampling, female gender, food consumption between meals, and smoking seem to have contributed to low buffering values. Snuff-taking habits, oral contraceptives, and protein consumption between meals were not associated with the buffering capacity.

  4. Improved dissolution rate of poorly soluble drug by incorporation of buffers.

    PubMed

    Preechagoon, D; Udomprateep, A; Manwiwattanagul, G

    2000-08-01

    This study focused on comparing dissolution rates of indomethacin after co-compressing with three different buffers (calcium carbonate, sodium carbonate, and sodium citrate) at pH 2 and 7. Factors affecting the dissolution rate were also examined, such as type and particle size of buffer and weight-to-weight ratio of drug to buffer. It was found that, at pH 7, the release rates of indomethacin with sodium carbonate (< 74 microns, all proportions) and sodium citrate (< 74 microns, 75% loading) at a 20-min test time were about 10-fold and 6-fold greater, respectively, than that of indomethacin alone. When the drug and buffer were compressed into tablets using a tableting machine, the release rates of indomethacin for the control, sodium carbonate incorporated (25% and 75% buffer loading), and sodium citrate incorporated (75% buffer loading) at a 15-min test time were 50%, 90%, 66%, and 67%, respectively.

  5. DNA interaction with Al- N, N'-bis(salicylidene)2,2'-phenylendiamine complex

    NASA Astrophysics Data System (ADS)

    Kashanian, S.; Gholivand, M. B.; Ahmadi, F.; Taravati, A.; Colagar, A. Hosseinzadeh

    2007-06-01

    The Al(III) complex, [Al(salophen)2H 2O]NO 3, was synthesized and characterized by spectroscopic (NMR and FT-IR) techniques. Then the binding of Schiff base complex of [Al(salophen)] + type, where salophen denotes N, N'-bis(salicylidene) 2,2-phenylendiamine to calf thymus DNA, has been investigated by spectrophotometric, circular dichroism, spectrofluorometric, melting temperature and viscosimetric techniques. This Al(III) complex showed absorption hyperchromism in the range of 310-390 nm, increase in melting temperature, some structural changes in specific viscosity, when bound to calf thymus DNA. The binding constant has been determined using absorption measurement and found to be 1.82 × 10 3 M -1 and 1.31 × 10 3 M -1 in HEPES and Tris-HCl buffers, respectively. Also the fluorescence spectral characteristics and interaction of Al-salophen complex with DNA have been studied. Al-salophen bound to DNA showed a marked increase in the fluorescence intensity along with a bathochromic shift (5 nm). The intersection point of the binding isotherm indicated a binding site size of 12 bp per bound complex molecule in both HEPES and Tris-HCl buffers. The experimental results showed that the Al-salophen complex bound to DNA by non-intercalative mode and major groove binding was the preferred mode of interaction

  6. Immobilisation of an antibacterial drug to Ti6Al4V components fabricated using selective laser melting

    NASA Astrophysics Data System (ADS)

    Vaithilingam, Jayasheelan; Kilsby, Samuel; Goodridge, Ruth D.; Christie, Steven D. R.; Edmondson, Steve; Hague, Richard J. M.

    2014-09-01

    Bacterial infections from biomedical implants and surgical devices are a major problem in orthopaedic, dental and vascular surgery. Although the sources of contaminations that lead to bacterial infections are known, it is not possible to control or avoid such infections completely. In this study, an approach to immobilise Ciprofloxacin® (an antibacterial drug) to phosphonic acid based self-assembled monolayers (SAMs) adsorbed on a selectively laser melted (SLM) Ti6Al4V structure, has been presented. X-ray photoelectron spectroscopy (XPS) and static water contact angle measurements confirmed the attachment of SAMs and the drug. Results showed that Ciprofloxacin® is highly stable under the oxidative conditions used in this study. In-vitro stability was estimated by immersing the Ciprofloxacin® immobilised substrates in 10 mM of Tris-HCl buffer (pH-7.4) for 42 days. The Tris-HCl buffer was analysed using UV-vis spectrophotometry at 7, 14, 28 and 42 day time intervals to determine the release of the immobilised drug. The drug was observed to release in a sustained manner. 50% of the drug was released after 4 weeks with approximately 40% of the drug remaining after 6 weeks. Antibacterial susceptibility tests revealed that the immobilised drug was therapeutically active upon its release. This study demonstrates the potential to use self-assembled monolayers to modify SLM fabricated surfaces with therapeutics.

  7. [Studies on detection of E. coli O157:H7 by ATP bioluminescence].

    PubMed

    Tang, Qian-Qian; Wang, Jian-Ping; Gai, Lin; Ye, Zun-Zhong; Ying, Yi-Bin

    2009-02-01

    In the present paper, a quantitative linear model betweena series of concentrations of E. coliO157 : H7 and counts by BPCL ultra weak luminescence analyzer was built up. And the influences of four different buffers with the same pH (pH = 7.4), Tris-HCl, PBS, KH2PO4-NaOH and Na2 HPO4-C6H8O7, and five different chemical substances with the same mass concentration (10 g x L), NaCl, KCl, NaOH, MgCl2 and NaH2PO4 on ATP bioluminescence were compared. The results showed that Tris-HCl was a suitable buffer for dilution, since it could distinguish well between different concentrations and had the lowest background signals. And MgCl2 could intensify luminescence distinctly, while the other four chemical substances decreased luminescence, of which NaOH decreased luminescence most obviously. Moreover, ATP bioluminescence was correlated well with conventional culture methods (r = 0.96), and the detection limit was 10(3) cells x mL(-1).

  8. Microstructural and potential dependence studies of urease-immobilized gold nanoparticles-polypyrrole composite film for urea detection.

    PubMed

    Rajesh; Puri, Nidhi; Mishra, Sujeet K; Laskar, Mariam J; Srivastava, Avanish K

    2014-01-01

    Gold nanoparticle-polypyrrole nanocomposite film was electrochemically deposited in a single-step polymerization of pyrrole in the presence of 3-mercaptopropionic acid (MPA)-capped gold nanoparticles (GNPs) and p-toluenesulfonic acid (pTSA) on the surface of an indium tin oxide (ITO)-coated glass plate. The carboxyl functional groups surrounding the GNPs within the polymer matrix were utilized for the immobilization of urease enzyme through carbodiimide coupling reaction for the construction of a Urs/GNP(MPA)-PPy/ITO-glass bioelectrode for urea detection in Tris-HCl buffer. The resulting bioelectrode film was characterized by atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The potentiometric response of the bioelectrode made of polymer nanocomposite films of two different thicknesses prepared at 100 and 250 mC cm(-2) charge densities, respectively, was studied towards the urea concentration in Tris-HCl buffer (pH 7.4). The thin polymer nanocomposite film-based bioelectrode prepared at 100 mC cm(-2) charge density exhibited a comparatively good potentiometric response than a thick 250 mC cm(-2) charge density film with a linear range of urea detection from 0.01 to 10 mM with a sensitivity of 29.7 mV per decade.

  9. Electrophoretic mobilities of cultured human embryonic kidney cells in various buffers

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Data on the electrophoretic mobility distributions of cells in the new D-1 buffer and the interlaboratory standardization of urokinase assay methods are presented. A table of cell strains and recent data on cell dispersal methods are also included. It was decided that glycerol in A-1 electrophoretic mobility data on cultured human embryonic kidney cells subjected to electrophoresis in this buffer. The buffer composition is presented.

  10. Doped Y.sub.2O.sub.3 buffer layers for laminated conductors

    DOEpatents

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2007-08-21

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the metallic substrate, the biaxially textured buffer layer comprising Y.sub.2O.sub.3 and a dopant for blocking cation diffusion through the Y.sub.2O.sub.3, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  11. Growth Optimization of YBa2NbO6 Buffer Layers (Postprint)

    DTIC Science & Technology

    2012-02-01

    single crystals, and IBAD MgO buffered Inconel substrates has been investigated. X-ray diffraction confirms the epitaxial growth of highly h00 oriented...YBNO thin films on single crystal substrates and IBAD MgO buffered Inconel substrates. The best average surface roughness of the YBNO films...diffraction, crystal, buffered, inconel , epitaxial, films, substrates, layers, growth, investigated, sufficient, preliminary, critical 16. SECURITY

  12. There is no capacity limited buffer in the Murdock (1962) free recall data

    PubMed Central

    2010-01-01

    Theories of short term memory often include a limited capacity “buffer”. Such a buffer contains items which do not decay at all but are overwritten by new data. I show that one of the experiments that fueled the buffer concept, the free recall experiments by Murdock (J Exp Psychol 64(5):482–488, 1962), does not contain such a buffer. PMID:22132047

  13. High effective cytosolic H+ buffering in mouse cortical astrocytes attributable to fast bicarbonate transport.

    PubMed

    Theparambil, Shefeeq M; Deitmer, Joachim W

    2015-09-01

    Cytosolic H(+) buffering plays a major role for shaping intracellular H(+) shifts and hence for the availability of H(+) for biochemical reactions and acid/base-coupled transport processes. H(+) buffering is one of the prime means to protect the cell from large acid/base shifts. We have used the H(+) indicator dye BCECF and confocal microscopy to monitor the cytosolic H(+) concentration, [H(+)]i, in cultured cortical astrocytes of wild-type mice and of mice deficient in sodium/bicarbonate cotransporter NBCe1 (NBCe1-KO) or in carbonic anhydrase isoform II (CAII-KO). The steady-state buffer strength was calculated from the amplitude of [H(+)]i transients as evoked by CO2/HCO3(-) and by butyric acid in the presence and absence of CO2/HCO3(-). We tested the hypotheses if, in addition to instantaneous physicochemical H(+) buffering, rapid acid/base transport across the cell membrane contributes to the total, "effective" cytosolic H(+) buffering. In the presence of 5% CO2/26 mM HCO3(-), H(+) buffer strength in astrocytes was increased 4-6 fold, as compared with that in non-bicarbonate, HEPES-buffered solution, which was largely attributable to fast HCO3 (-) transport into the cells via NBCe1, supported by CAII activity. Our results show that within the time frame of determining physiological H(+) buffering in cells, fast transport and equilibration of CO2/H(+)/HCO3(-) can make a major contribution to the total "effective" H(+) buffer strength. Thus, "effective" cellular H(+) buffering is, to a large extent, attributable to membrane transport of base equivalents rather than a purely passive physicochemical process, and can be much larger than reported so far. Not only physicochemical H(+) buffering, but also rapid import of HCO3(-) via the electrogenic sodium-bicarbonate cotransporter NBCe1, supported by carbonic anhydrase II (CA II), was identified to enhance cytosolic H(+) buffer strength substantially.

  14. Relationships between soil physicochemical, microbiological properties, and nutrient release in buffer soils compared to field soils.

    PubMed

    Stutter, Marc I; Richards, Samia

    2012-01-01

    The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams.

  15. High-throughput and multiplexed regeneration buffer scouting for affinity-based interactions.

    PubMed

    Geuijen, Karin P M; Schasfoort, Richard B; Wijffels, Rene H; Eppink, Michel H M

    2014-06-01

    Affinity-based analyses on biosensors depend partly on regeneration between measurements. Regeneration is performed with a buffer that efficiently breaks all interactions between ligand and analyte while maintaining the active binding site of the ligand. We demonstrated a regeneration buffer scouting using the combination of a continuous flow microspotter with a surface plasmon resonance imaging platform to simultaneously test 48 different regeneration buffers on a single biosensor. Optimal regeneration conditions are found within hours and consume little amounts of buffers, analyte, and ligand. This workflow can be applied to any ligand that is coupled through amine, thiol, or streptavidin immobilization.

  16. Effects of hypertonic buffer composition on lymph node uptake and bioavailability of rituximab, after subcutaneous administration.

    PubMed

    Fathallah, Anas M; Turner, Michael R; Mager, Donald E; Balu-Iyer, Sathy V

    2015-03-01

    The subcutaneous administration of biologics is highly desirable; however, incomplete bioavailability after s.c. administration remains a major challenge. In this work we investigated the effects of excipient dependent hyperosmolarity on lymphatic uptake and plasma exposure of rituximab as a model protein. Using Swiss Webster (SW) mice as the animal model, we compared the effects of NaCl, mannitol and O-phospho-L-serine (OPLS) on the plasma concentration of rituximab over 5 days after s.c. administration. An increase was observed in plasma concentrations in animals administered rituximab in hypertonic buffer solutions, compared with isotonic buffer. Bioavailability, as estimated by our pharmacokinetic model, increased from 29% in isotonic buffer to 54% in hypertonic buffer containing NaCl, to almost complete bioavailability in hypertonic buffers containing high dose OPLS or mannitol. This improvement in plasma exposure is due to the improved lymphatic trafficking as evident from the increase in the fraction of dose trafficked through the lymph nodes in the presence of hypertonic buffers. The fraction of the dose trafficked through the lymphatics, as estimated by the model, increased from 0.05% in isotonic buffer to 13% in hypertonic buffer containing NaCl to about 30% for hypertonic buffers containing high dose OPLS and mannitol. The data suggest that hypertonic solutions may be a viable option for improving s.c. bioavailability.

  17. Neurobehavioral assessment of maternal odor in developing rat pups: implications for social buffering

    PubMed Central

    Al Aïn, Syrina; Perry, Rosemarie E.; Nuñez, Bestina; Kayser, Kassandra; Hochman, Chase; Brehman, Elizabeth; LaComb, Miranda; Wilson, Donald A.; Sullivan, Regina M.

    2016-01-01

    Social support can attenuate the behavioral and stress hormone response to threat, a phenomenon called social buffering. The mother’s social buffering of the infant is one of the more robust examples; yet we understand little about the neurobiology. Using a rodent model, we explore the neurobiology of social buffering by assessing neural processing of the maternal odor, a major cue controlling social buffering in rat pups. We used pups before (postnatal day (PN) 7) and after (PN14, PN23) the functional emergence of social buffering. Pups were injected with 14C 2-deoxyglucose (2-DG) and presented with the maternal odor, a control preferred odor incapable of social buffering (acetophenone), or no odor. Brains were removed, processed for autoradiography and brain areas identified as important in adult social buffering were assessed, including the amygdala basolateral complex (Basolateral Amygdala [BLA]), medial prefrontal cortex (mPFC), and anterior cingulate cortex (ACC). Results suggest dramatic changes in the processing of maternal odor. PN7 pups show mPFC and ACC activation, although PN14 pups showed no activation of the mPFC, ACC, or BLA. All brain areas assessed were recruited by PN23. Additional analysis suggests substantial changes in functional connectivity across development. Together, these results imply complex nonlinear transitions in the neurobiology of social buffering in early life that may provide insight into the changing role of the mother in supporting social buffering. PMID:26934130

  18. The concept of "buffering" in systems and control theory: from metaphor to math.

    PubMed

    Schmitt, Bernhard M

    2004-10-04

    The paradigm of "buffering" is used increasingly for the description of diverse "systemic" phenomena encountered in evolutionary genetics, ecology, integrative physiology, and other areas. However, in this new context, the paradigm has not yet matured into a truly quantitative concept inasmuch as it lacks a corresponding quantitative measure of "systems-level buffering strength". Here, I develop such measures on the basis of a formal and general approach to the quantitation of buffering action. "Systems-level buffering" is shown to be synonymous with "disturbance rejection" in feedback-control systems, and can be quantitated by means of dimensionless proportions between partial flows in two-partitioned systems. The units allow either the time-independent, "static" buffering properties or the time-dependent, "dynamic" ones to be measured. Analogous to this "resistance to change", one can define and measure the "conductance to change"; this quantity corresponds to "set-point tracking" in feedback-control systems. Together, these units provide a systematic framework for the quantitation of buffering action in systems biology, and reveal the common principle behind systems-level buffering, classical acid-base buffering, and multiple other manifestations of buffering.

  19. Effect of buffer structures on AlGaN/GaN high electron mobility transistor reliability

    SciTech Connect

    Liu, L.; Xi, Y. Y.; Ren, F.; Pearton, S. J.; Laboutin, O.; Cao, Yu; Johnson, Wayne J.; Kravchenko, Ivan I

    2012-01-01

    AlGaN/GaN high electron mobility transistors (HEMTs) with three different types of buffer layers, including a GaN/AlGaN composite layer, or 1 or 2 lm GaN thick layers, were fabricated and their reliability compared. The HEMTs with the thick GaN buffer layer showed the lowest critical voltage (Vcri) during off-state drain step-stress, but this was increased by around 50% and 100% for devices with the composite AlGaN/GaN buffer layers or thinner GaN buffers, respectively. The Voff - state for HEMTs with thin GaN and composite buffers were 100 V, however, this degraded to 50 60V for devices with thick GaN buffers due to the difference in peak electric field near the gate edge. A similar trend was observed in the isolation breakdown voltage measurements, with the highest Viso achieved based on thin GaN or composite buffer designs (600 700 V), while a much smaller Viso of 200V was measured on HEMTs with the thick GaN buffer layers. These results demonstrate the strong influence of buffer structure and defect density on AlGaN/GaN HEMT performance and reliability.

  20. Buffering capacity of the chief components of nutritive media for algae.

    PubMed

    Lívanský, K

    1982-01-01

    The buffering capacity of solutions of KH2PO4 and NaHCO3 increases with their concentration, the behaviour being describable by mathematical expressions. Solutions of KH2PO4 prepared from tap water exhibit a buffering capacity higher by an order of magnitude than those prepared from distilled water. However, there is no difference between the buffering capacities of solutions of NaHCO3 prepared from tap and distilled water. Urea and NH4NO3 have almost no effect on the buffering capacities of solutions.

  1. Effects of hypertonic buffer composition on lymph node uptake and bioavailability of rituximab, after subcutaneous administration

    PubMed Central

    Fathallah, Anas M.; Turner, Michael R.; Balu-Iyer, Sathy V.

    2015-01-01

    Subcutaneous administration of biologics is highly desirable; however, incomplete bioavailability after sc administration remains a major challenge. In this work we investigated the effects of excipient dependent hyper-osmolarity on lymphatic uptake and plasma exposure of rituximab as a model protein. Using Swiss Webster (SW) mice as our animal model, we compared the effects of NaCl, mannitol and, O-Phospho-L-Serine (OPLS) on plasma concentration of rituximab over 5 days after sc administration. We observed an increase in plasma concentrations in animals administered rituximab in hypertonic buffer solutions, as compared to isotonic buffer. Bioavailability, as estimated by our pharmacokinetic model, increased from 29% in isotonic buffer to 54% in hypertonic buffer containing NaCl, to almost complete bioavailability in hypertonic buffers containing high dose OPLS or mannitol. This improvement in plasma exposure is due to improved lymphatic trafficking as evident from the increase in the fraction of dose trafficked through the lymph node in the presence of hypertonic buffers. The fraction of the dose trafficked through the lymphatic, as estimated by the model, increased from 0.05 % in isotonic buffer to 13% in hyper-tonic buffer containing NaCl to about 30% for hypertonic buffers containing high dose OPLS and mannitol. Our data suggests that hypertonic solutions may be a viable option to improve sc bioavailability. PMID:25377184

  2. Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards

    NASA Astrophysics Data System (ADS)

    Novara, A.; Gristina, L.; Guaitoli, F.; Santoro, A.; Cerdà, A.

    2013-04-01

    When soil nitrate levels are inadequate, plants suffer nitrogen deficiency but when the levels are excessive, nitrates (NO3-N) can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The experimental site, a 10 m wide and 80 m long area at the bottom of a vineyard was selected in Sicily. The soil between vine rows and upslope of the buffer strip (seeded with Lolium perenne) and non-buffer strips (control) was managed conventionally and with one of two cover crops (Triticum durum and Vicia sativa cover crop). Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. L. perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. V. sativa cover crop management contribute with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduce the nitrate by 42% with and by 46% with a 9 m buffer strip.

  3. Mechanisms and functional implications of social buffering in infants: Lessons from animal models.

    PubMed

    Sullivan, Regina M; Perry, Rosemarie E

    2015-01-01

    Social buffering, which is the attenuation of stress hormone release by a social partner, occurs in many species throughout the lifespan. Social buffering of the infant by the caregiver is particularly robust, and animal models using infant rodents are uncovering the mechanisms and neural circuitry supporting social buffering. At birth, the hypothalamic-pituitary-adrenal (HPA) stress system is functional but is suppressed via extended social buffering by the mother: the profound social buffering effects of the mother can last for 1-2 hours when pups are removed from the mother. At 10 days of age, pups begin to mount a stress response immediately when separated from the mother. The stimuli from the mother supporting social buffering are broad, for tactile stimulation, milk, and an anesthetized mother (no maternal behavior) all sufficiently support social buffering. The mother appears to produce social buffering by blocking norepinephrine (NE) release into the hypothalamic paraventricular nucleus (PVN), which blocks HPA activation. Since the infant amygdala relies on the presence of corticosterone (CORT), this suggests that social buffering of pups by the mother attenuates the neurobehavioral stress response in infancy and prevents pups from learning about threat within mother-infant interactions.

  4. Auto-protective redox buffering systems in stimulated macrophages

    PubMed Central

    Ferret, Pierre-Jacques; Soum, Emmanuelle; Negre, Olivier; Fradelizi, Didier

    2002-01-01

    Background Macrophages, upon encounter with micro-organisms or stimulated by cytokines, produce various effector molecules aimed at destroying the foreign agents and protecting the organism. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are front line molecules exerting strong cytotoxic activities against micro-organisms and many cells, including macrophages themselves. Using cells of the murine macrophage cell line (RAW 264.7) stimulated in vitro with lipopolysaccharide (LPS) and/or interferon (IFN-γ), which induce strong endogenous NO production, we examined by which mechanisms a fraction of activated macrophages protect themselves from nitrosative stress and manage to escape destruction? Results We observed that survivors (10–50% depending on the experiments) had acquired a resistant phenotype being capable to survive when further exposed in vitro to an apoptosis inducing dose of the NO donor compound DETA-NO. These cells expressed an increased steady-state levels of Mn SOD, CuZn SOD and catalase mRNA (130–200%), together with an increased activity of the corresponding enzymes. Intracellular concentration of glutathione was also increased (× 3.5 fold at 6 hours, still maintained × 5.2 fold at 48 hours). Neither mRNA for glutathione peroxydase, γ-glutamylcysteine synthase and glutathione reductase, nor thioredoxine and thioredoxine reductase, were significantly modified. Additional experiments in which RAW 264.7 cells were stimulated with LPS and/or IFN-γ in the presence of relatively specific inhibitors of both Mn and Cu/Zn SOD, aminotriazol (ATZ) catalase inhibitor and buthionine sulfoximine (BSO) glutathione inhibitor, showed that inhibiting LPS-induced up-regulation of intracellular redox buffering systems also prevented acquisition of the resistant phenotype. Conclusions Our data suggest a direct causal relationship between survival of a fraction of macrophages and a up-regulation of key sets of auto-protective intracellular

  5. Development and Evaluation of a Riparian Buffer Mapping Tool

    USGS Publications Warehouse

    Milheim, Lesley E.; Claggett, Peter R.

    2008-01-01

    Land use and land cover within riparian areas greatly affect the conditions of adjacent water features. In particular, riparian forests provide many environmental benefits, including nutrient uptake, bank stabilization, steam shading, sediment trapping, aquatic and terrestrial habitat, and stream organic matter. In contrast, residential and commercial development and associated transportation infrastructure increase pollutant and nutrient loading and change the hydrologic characteristics of the landscape, thereby affecting both water quality and habitat. Restoring riparian areas is a popular and cost effective restoration technique to improve and protect water quality. Recognizing this, the Chesapeake Executive Council committed to restoring 10,000 miles of riparian forest buffers throughout the Chesapeake Bay watershed by the year 2010. In 2006, the Chesapeake Executive Council further committed to 'using the best available...tools to identify areas where retention and expansion of forests is most needed to protect water quality'. The Chesapeake Bay watershed encompasses 64,000 square miles, including portions of six States and Washington, D.C. Therefore, the interpretation of remotely sensed imagery provides the only effective technique for comprehensively evaluating riparian forest protection and restoration opportunities throughout the watershed. Although 30-meter-resolution land use and land cover data have proved useful on a regional scale, they have not been equally successful at providing the detail required for local-scale assessment of riparian area characteristics. Use of high-resolution imagery (HRI) provides sufficient detail for local-scale assessments, although at greater cost owing to the cost of the imagery and the skill and time required to process the data. To facilitate the use of HRI for monitoring the extent of riparian forest buffers, the U.S. Forest Service and the U.S. Geological Survey Eastern Geographic Science Center funded the

  6. Removal of sample background buffering ions and myoglobin enrichment via a pH junction created by discontinuous buffers in capillary electrophoresis.

    PubMed

    Booker, Christina J; Sun, Samuel; Woolsey, Sarah; Mejia, Jose S; Yeung, Ken K-C

    2011-08-19

    Traditional CE sample stacking is ineffective for samples containing a high concentration of salt and/or buffer. We recently reported the use of a discontinuous buffer system for protein enrichment that was applicable to samples containing millimolar concentrations of salt. In this paper, the technique was investigated for samples containing unwanted buffering ions, including TRIS, MES, and phosphate, which are commonly used in biological sample preparation. Using myoglobin as a model protein, the results demonstrated that background buffering ions can be effectively removed or separated from the enriched protein. The key is to use either the acid or the base of the discontinuous buffers to adjust the pH of the sample, such that the net charge of the unwanted buffering ions is near-zero. The successful isolation and enrichment of myoglobin from up to 100 mM TRIS and 50 mM MES was demonstrated. The enrichment factors remained at approximately 200. Removal of phosphate was more challenging because its net charge was anionic in both the acid and the base of the discontinuous buffers. The enrichment was only achievable up to 30 mM of sodium phosphate, the enrichment factors observed were significantly lower, below 50, and the process was delayed due to the higher ionic strength resulted from phosphate. The migration of phosphate during enrichment was studied using a UV-absorbing analogue, phenyl phosphate. In addition, Simul 5.0 was used to simulate the discontinuous buffers in the absence and presence of TRIS and phosphate. The stimulated TRIS and phosphate concentration profiles were generally in agreement with the experimental results. The simulation also provided a better understanding on the effect of phosphate on the formation of the pH junction.

  7. Effect of Oxide Buffer Layer on the Thermochromic Properties of VO2 Thin Films

    NASA Astrophysics Data System (ADS)

    Koo, Hyun; Xu, Lu; Ko, Kyeong-Eun; Ahn, Seunghyun; Chang, Se-Hong; Park, Chan

    2013-12-01

    VO2 thin films were deposited on soda lime glass substrates with ZnO, TiO2, SnO2, and CeO2 thin films applied as buffer layers between the VO2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO2 film. Buffer layers with thicknesses over 50 nm were found to affect the formation of VO2 film, which was confirmed by XRD spectra. By using ZnO, TiO2, and SnO2 buffer layers, monoclinic VO2 (VO2(M)) film was successfully fabricated on soda lime glass at 370 °C. On the contrary, films of VO2(B), which is known to have no phase transition near room temperature, were formed rather than VO2(M) when the film was deposited on CeO2 buffer layer at the same film deposition temperature. The excellent thermochromic properties of the films deposited on ZnO, TiO2, and SnO2 buffer layers were confirmed from the temperature dependence of electrical resistivity from room temperature to 80 °C. Especially, due to the tendency of ZnO thin film to grow with a high degree of preferred orientation on soda lime glass at low temperature, the VO2 film deposited on ZnO buffer layer exhibits the best thermochromic properties compared to those on other buffer layer materials used in this study. These results suggest that deposition of VO2 films on soda lime glass at low temperature with excellent thermochromic properties can be achieved by considering the buffer layer material having structural similarity with VO2. Moreover, the degree of crystallization of buffer layer is also related with that of VO2 film, and thus ZnO can be one of the most effective buffer layer materials.

  8. Amelogenin-enamelin association in phosphate buffered saline

    PubMed Central

    Yang, Xiudong; Fan, Daming; Mattew, Shibi; Moradian-Oldak, Janet

    2011-01-01

    The structures and interactions among the macromolecules in the enamel extracellular matrix play vital roles in regulating hydroxyapatite crystal nucleation, growth and maturation. We used dynamic light scattering, circular dichroism, fluorescence spectroscopy and transmission electron microscopy to investigate association of amelogenin and the 32-kDa enamelin, at physiological pH 7.4, in phosphate buffered saline (PBS). Amelogenin (rP148) self-assembly behavior was altered following addition of the 32-kDa enamelin. Dynamic light scattering revealed a trend of decrease in aggregate size in the solution following the addition of enamelin to amelogenin. A blue-shift and intensity increase of the ellipticity minima of rP148 in the circular dichroism spectra, upon the addition of the 32-kDa enamelin, suggest a direct interaction between the two proteins. In the fluorescence spectra, the maximum emission of rP148 was red-shifted from 335 to 341 nm with a marked intensity increase in the presence of enamelin as a result of complexation of the two proteins. In agreement with DLS data, TEM imaging showed that the 32-kDa enamelin dispersed the amelogenin aggregates into oligomeric particles and stabilizing them. Our study provides novel insights into understanding possible cooperation between enamelin and amelogenin in macromolecular co-assembly and in controlling enamel mineral formation. PMID:22243267

  9. Are temperate mature forests buffered from invasive lianas?

    USGS Publications Warehouse

    Pavlovic, Noel B.; Leicht-Young, Stacey A.

    2011-01-01

    Mature and old-growth forests are often thought to be buffered against invasive species due to low levels of light and infrequent disturbance. Lianas (woody vines) and other climbing plants are also known to exhibit lower densities in older forests. As part of a larger survey of the lianas of the southern Lake Michigan region in mature and old-growth forests, the level of infestation by invasive lianas was evaluated. The only invasive liana detected in these surveys was Celastrus orbiculatus Thunb. (Celastraceae). Although this species had only attached to trees and reached the canopy in a few instances, it was present in 30% of transects surveyed, mostly as a component of the ground layer. Transects with C. orbiculatus had higher levels of soil potassium and higher liana richness than transects without. In contrast, transects with the native C. scandens had higher pH, sand content, and soil magnesium and lower organic matter compared to transects where it was absent. Celastrus orbiculatus appears to be a generalist liana since it often occurs with native lianas. Celastrus orbiculatus poses a substantial threat to mature forests as it will persist in the understory until a canopy gap or other disturbance provides the light and supports necessary for it to ascend to the canopy and damage tree species. As a result, these forests should be monitored by land managers so that C. orbiculatus eradication can occur while invasions are at low densities and restricted to the ground layer.

  10. Superconducting composite with multilayer patterns and multiple buffer layers

    DOEpatents

    Wu, Xin D.; Muenchausen, Ross E.

    1993-01-01

    An article of manufacture including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superco n FIELD OF THE INVENTION The present invention relates to the field of superconducting articles having two distinct regions of superconductive material with differing in-plane orientations whereby the conductivity across the boundary between the two regions can be tailored. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

  11. Psychobiology of social support: the social dimension of stress buffering.

    PubMed

    Ditzen, Beate; Heinrichs, Markus

    2014-01-01

    Social integration and social support have a substantial influence on individual health and longevity, an effect assumed to be mediated through reduced stress reactivity in support recipients. However, considerable variability in individual responses to social support has been documented, suggesting that the beneficial effect of social support interacts with early experiences, genetically influenced differences in biological systems mediating social behavior, personality traits, and psychopathology. Here we outline the historical background of social support research, including epidemiological studies, laboratory studies, and field studies on the subject of social support and health, with regard to different psychobiological effector systems. Most recent research has focused on brain mechanisms which link social integration or social support with reduced neural threat responses. As numerous mental disorders are associated with considerable social impairment, understanding the potentially underlying mechanisms of neural plasticity in relation to social support, stress buffering and health in these disorders can help tailor new diagnostic and treatment strategies. Thus, theories of socially-driven emotional learning and memory, as presented in this review, might eventually lead to psychobiology-based treatment concepts for mental disorders involving social deficits.

  12. Perceived Personal Control Buffers Terminal Decline in Well-Being

    PubMed Central

    Gerstorf, Denis; Heckhausen, Jutta; Ram, Nilam; Infurna, Frank J.; Schupp, Juergen; Wagner, Gert G.

    2015-01-01

    Recent research has repeatedly demonstrated that well-being typically evinces precipitous deterioration close to the end of life. However, the determinants of individual differences in these terminal declines are note well understood. In this study, we examine the role of perceived personal control as a potential buffer against steep terminal declines in well-being. We applied single- and multi-phase growth models to up to 25-year longitudinal data from 1,641 now deceased participants of the national German Socio-Economic Panel Study (SOEP; age at death: M = 74 years; SD = 14; 49% women). Results revealed that perceiving more personal control over one’s life was related to subsequently higher late-life well-being, less severe rates of late-life declines, and a later onset of terminal decline. Associations were independent of key predictors of mortality, including age, gender, SES, and disability. These findings suggest that feeling in control may ameliorate steep end-of-life decline in well-being. We also discuss scenarios for when and how processes of goal disengagement and giving up control may become beneficial. PMID:25244480

  13. Brood comb as a humidity buffer in honeybee nests

    NASA Astrophysics Data System (ADS)

    Ellis, Michael B.; Nicolson, Sue W.; Crewe, Robin M.; Dietemann, Vincent

    2010-04-01

    Adverse environmental conditions can be evaded, tolerated or modified in order for an organism to survive. During their development, some insect larvae spin cocoons which, in addition to protecting their occupants against predators, modify microclimatic conditions, thus facilitating thermoregulation or reducing evaporative water loss. Silk cocoons are spun by honeybee ( Apis mellifera) larvae and subsequently incorporated into the cell walls of the wax combs in which they develop. The accumulation of this hygroscopic silk in the thousands of cells used for brood rearing may significantly affect nest homeostasis by buffering humidity fluctuations. This study investigates the extent to which the comb may influence homeostasis by quantifying the hygroscopic capacity of the cocoons spun by honeybee larvae. When comb containing cocoons was placed at high humidity, it absorbed 11% of its own mass in water within 4 days. Newly drawn comb composed of hydrophobic wax and devoid of cocoons absorbed only 3% of its own mass. Therefore, the accumulation of cocoons in the comb may increase brood survivorship by maintaining a high and stable humidity in the cells.

  14. Efflux of red cell water into buffered hypertonic solutions.

    PubMed

    OLMSTEAD, E G

    1960-03-01

    Buffered NaCl solutions hypertonic to rabbit serum were prepared and freezing point depressions of each determined after dilution with measured amounts of water. Freezing point depression of these dilutions was a linear function of the amount of water added. One ml. of rabbit red cells was added to each 4 ml. of the hypertonic solutions and after incubation at 38 degrees C. for 30 minutes the mixture was centrifuged and a freezing point depression determined on the supernatant fluid. The amount of water added to the hypertonic solutions by the red cells was calcuated from this freezing point depression. For each decrease in the freezing point of -0.093 degrees C. of the surrounding solution red cells gave up approximately 5 ml. of water per 100 ml. of red cells in the range of -0.560 to -0.930 degrees C. Beyond -0.930 degrees C. the amount of water given up by 100 ml. of red cells fits best a parabolic equation. The maximum of this equation occurred at a freezing point of the hypertonic solution of -2.001 degrees C. at which time the maximum amount of water leaving the red cells would be 39.9 ml. per 100 ml. of red cells. The data suggest that only about 43 per cent of the red cell water is available for exchange into solutions of increasing tonicity.

  15. The dual role of lakes as buffers and amplifiers of dissolved organic matter temporal dynamics: Buffering transport and amplifying transformation

    NASA Astrophysics Data System (ADS)

    Ejarque, Elisabet; Schelker, Jakob; Khan, Samiullah; Hollaus, Lisa-Maria; Steniczka, Gertraud; Kainz, Martin; Battin, Tom

    2016-04-01

    Lakes that disrupt the flow of water and its constituents within the fluvial continuum can modify the downstream dynamics of dissolved organic matter (DOM). Potential causes of this change may include the hydrological buffering capacity of lakes relative to streams and rivers and the amplification of biotic processes. To test this hypothesis, we measured DOM quantity and quality at the inflow and outflow of sub-alpine Lake Lunz (Lower Austria) during one year. DOM quality was characterised using optical metrics indicative of the humic-like composition (fluorescence peak C), humification (HIX), and aromaticity (SUVA) degree, predominance of autochthonous components (BIX), and average molecular weight (E2:E3). Total annual variability was found to be lower in the outflow compared with the inflow (SDout:SDin < 1) for dissolved organic carbon (DOC) concentration and HIX. These variables showed a minimal seasonal variation in both inflow and outflow, together with a more accentuated response to hydrology in the inflow. Mean DOC concentration was significantly higher in the outflow (1.70 ± 0.14 mg L-1) than in the inflow (1.3 ± 0.25 mg L-1), and this pattern was only occasionally reversed during high flow. By contrast, the total annual variability of peak C, SUVA, BIX and E2:E3 was higher in the outflow than in the inflow (SDout:SDin > 1). This was due to the large seasonal variability in the outflow, which contrasted with a reduced temporal dynamics in the inflow. Combined, this created a shift from similar inflow-outflow DOM characteristics during winter, to uncoupled DOM characteristics during summer. This uncoupling consisted in a higher signal of the autotrophic origin of DOM, a lower average molecular weight, as well as a lower aromatic and humic-like content in the outflow. Overall, these results highlight the role of the Lake Lunz as a DOC source and as a buffer of hydrological pulses of DOC export. Moreover, results emphasise the capacity of the lake to

  16. Importance Sampling in the Evaluation and Optimization of Buffered Failure Probability

    DTIC Science & Technology

    2015-07-01

    probability in design optimization problems. The buffered failure probability is more conservative and possesses properties that make it more...The buffered failure probability is more conservative and possesses properties that make it more convenient to compute and optimize. Since a failure

  17. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    DOEpatents

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  18. Pain reduction in local anesthetic administration through pH buffering.

    PubMed

    Christoph, R A; Buchanan, L; Begalla, K; Schwartz, S

    1988-02-01

    The effects of pH buffering on the pain of administration and efficacy of three local anesthetics (1% lidocaine, 1% lidocaine with 1:100,000 epinephrine, and 1% mepivacaine) were investigated in a randomized, prospective, double-blind study of 25 adult volunteers. Plain and buffered solutions of the three local anesthetics were prepared, and a 0.5 intradermal injection of each was administered. Pain of anesthetic infiltration was rated from zero to ten. The area of anesthetized skin surrounding each injection site was measured at time intervals following each injection. Buffering the local anesthetics significantly reduced the mean quantitative pain estimates compared to the nonbuffered controls: 1) 1% lidocaine compared with buffered 1% lidocaine, 4.9 +/- 0.4 versus 1.1 +/- 0.2 (P less than 10(-6)); 2) 1% lidocaine with epinephrine compared with buffered 1% lidocaine with epinephrine, 5.1 +/- 0.4 versus 1.8 +/- 0.4 (P less than 10(-6)); and 3) 1% mepivacaine compared with buffered 1% mepivacaine, 5.1 +/- 0.4 versus 0.9 +/- 0.2 (P less than 10(-6)). Onset, extent, and duration of skin anesthesia were not statistically altered by pH buffering. The pain of local anesthetic administration can be dramatically reduced by buffering the local anesthetic prior to its infiltration. Anesthetic efficacy is not compromised, and patient acceptance may be significantly increased.

  19. Influence of phosphate ions on buffer capacity of soil humic acids

    NASA Astrophysics Data System (ADS)

    Boguta, P.; Sokołowska, Z.

    2012-02-01

    The object of this study was to determine change of natural buffer capacity of humic acids by strong buffering agents, which were phosphate ions. Studies were carried out on the humic acids extracted from peat soils. Additional information was obtained by determination of water holding capacity, density, ash and pH for peats and optical parameter Q4/6 for humic acids. Humic acid suspensions exhibited the highest buffer properties at low pH and reached maximum at pH ~ 4. Phosphates possessed buffer properties in the pH range from 4.5 to 8.0. The maximum of buffering was at pH~6.8 and increased proportionally with an increase in the concentration of phosphate ions. The study indicated that the presence of phosphate ions may strongly change natural buffer capacity of humic acids by shifting buffering maximum toward higher pH values. Significant correlations were found for the degree of the secondary transformation with both the buffer capacity and the titrant volume used during titration.

  20. Super Buffer: a systolic VLSI graphics engine for real-time raster image generation

    SciTech Connect

    Gharachlorloo, N.

    1985-01-01

    The new Super Buffer family of systems for real time generation of three dimensional, general-purpose, interactive and dynamic raster images is the subject of this thesis. In these systems the conventional 512 x 512 frame buffer is replaced by a 512 x 1 virtual scanline buffer. Image updating, buffering and refreshing are all performed by a single chip Systolic VLSI Raster Graphics Engine. The Engine is composed of an array of identical specialized Pixel Processors which collaborate to break the real time computation barrier by performing several billion Pixel operations per second in order to generate raster images in real time. A basic Super Buffer system has been successfully implemented and tested on a single prototype board connected to an IBM PC-AT. This approach is compared and contrasted to other high performance frame buffer based system architectures. The flexibility and power of the Super Buffer architecture is demonstrated by its ability to execute in real time the computationally intensive hidden surface removal and linear shading algorithms. Furthermore, the basic Super Buffer can be expanded in hardware to handle higher resolution displays and to generate images of high complexity, forming an entire family of systems with the same general architecture.

  1. The Maintenance of Cross-Domain Associations in the Episodic Buffer

    ERIC Educational Resources Information Center

    Langerock, Naomi; Vergauwe, Evie; Barrouillet, Pierre

    2014-01-01

    The episodic buffer has been described as a structure of working memory capable of maintaining multimodal information in an integrated format. Although the role of the episodic buffer in binding features into objects has received considerable attention, several of its characteristics have remained rather underexplored. This is the case for its…

  2. Buffer AVL Alone Does Not Inactivate Ebola Virus in a Representative Clinical Sample Type.

    PubMed

    Smither, Sophie J; Weller, Simon A; Phelps, Amanda; Eastaugh, Lin; Ngugi, Sarah; O'Brien, Lyn M; Steward, Jackie; Lonsdale, Steve G; Lever, Mark S

    2015-10-01

    Rapid inactivation of Ebola virus (EBOV) is crucial for high-throughput testing of clinical samples in low-resource, outbreak scenarios. The EBOV inactivation efficacy of Buffer AVL (Qiagen) was tested against marmoset serum (EBOV concentration of 1 × 10(8) 50% tissue culture infective dose per milliliter [TCID50 · ml(-1)]) and murine blood (EBOV concentration of 1 × 10(7) TCID50 · ml(-1)) at 4:1 vol/vol buffer/sample ratios. Posttreatment cell culture and enzyme-linked immunosorbent assay (ELISA) analysis indicated that treatment with Buffer AVL did not inactivate EBOV in 67% of samples, indicating that Buffer AVL, which is designed for RNA extraction and not virus inactivation, cannot be guaranteed to inactivate EBOV in diagnostic samples. Murine blood samples treated with ethanol (4:1 [vol/vol] ethanol/sample) or heat (60°C for 15 min) also showed no viral inactivation in 67% or 100% of samples, respectively. However, combined Buffer AVL and ethanol or Buffer AVL and heat treatments showed total viral inactivation in 100% of samples tested. The Buffer AVL plus ethanol and Buffer AVL plus heat treatments were also shown not to affect the extraction of PCR quality RNA from EBOV-spiked murine blood samples.

  3. Tested Demonstrations: Buffer Capacity of Various Acetic Acid-Sodium Acetate Systems: A Lecture Experiment.

    ERIC Educational Resources Information Center

    Donahue, Craig J.; Panek, Mary G.

    1985-01-01

    Background information and procedures are provided for a lecture experiment which uses indicators to illustrate the concept of differing buffer capacities by titrating acetic acid/sodium acetate buffers with 1.0 molar hydrochloric acid and 1.0 molar sodium hydroxide. A table with data used to plot the titration curve is included. (JN)

  4. Influence of different buffers (HEPES/MOPS) on keratinocyte cell viability and microbial growth.

    PubMed

    Dias, Kássia de Carvalho; Barbugli, Paula Aboud; Vergani, Carlos Eduardo

    2016-06-01

    This study assessed the effect of the buffers 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) and 3-(N-morpholino) propanesulfonic acid (MOPS) on keratinocyte cell viability and microbial growth. It was observed that RPMI buffered with HEPES, supplemented with l-glutamine and sodium bicarbonate, can be used as a more suitable medium to promote co-culture.

  5. Two-tiered partial buffering for contention resolution in optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Dash, Arabind; Jain, Shubham; Gahlot, Amar; Gangopadhyay, Ranjan

    2005-02-01

    The main challenge concerning the design of an optical packet switch is the issue of contention resolution. This paper introduces an optical packet switch architecture, with a two-tiered partially shared buffer using a novel buffer scheduling scheme. The traffic scheduling in the partially shared buffers is done in a hierarchical fashion to ensure the maximum router throughput. We compare the performance of the proposed strategy with single and multiple groups of partially shared buffers, keeping the overall buffer size constant. The performance analysis has been done for a Bernoulli distributed traffic at varying loads. The simulation results indicate a significant improvement in the packet loss probability. A remarkable advantage of the suggested architecture is that it obviates the need for wavelength conversion, thereby achieving a reduction in the infrastructural cost involved in the employment of wavelength converters. The secondary benefits include the elimination of the delay incurred due to searching for the appropriate wavelength and tuning of the wavelength converter. Also, the complexity associated with the accommodation of packets in partially shared buffers is reduced from O(n) to O(1) in comparison to n-groups of partially shared buffers as the search for the least queued partial buffer is replaced by a Boolean decision for every contending packet. Thus, in addition to enhancing the router performance in terms of the packet loss probability, the proposed strategy also augments the router speed.

  6. Investigation of the optical buffer tube deformation influence on fiber attenuation property loss

    NASA Astrophysics Data System (ADS)

    Andreev, Vladimir A.; Burdin, Vladimir A.; Gavryushin, Sergey A.; Nikulina, Tatiana G.

    2008-12-01

    In article experimental results increase attenuation in dependence of deformation optical buffer tube supply. Subsequent to the results of tests quantitative estimate increase attenuation in dependence of deformation optical buffer tube receive, calculate of the coefficients for allowed value deformation tube estimate.

  7. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    DOEpatents

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  8. A Review of Effectiveness of Vegetative Buffers on Sediment Trapping in Agricultural Areas

    EPA Science Inventory

    In recent years, there has been growing recognition of the importance of riparian buffers between agricultural fields and waterbodies. Riparian buffers play an important role in mitigating the impacts of land use activities on water quality and aquatic ecosystems. However, eval...

  9. Reconnecting tile drainage to riparian buffer hydrology for enhanced nitrate removal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are a proven practice for removing NO3 from both overland flow and shallow groundwater. However, in landscapes with artificial subsurface (tile) drainage most of the subsurface flow leaving fields is passed through the buffers in drainage pipes leaving little opportunity for NO3 rem...

  10. Buffer Effects in the Solubility, Nucleation and Growth of Chicken Egg White Lysozyme

    NASA Technical Reports Server (NTRS)

    Gibson, Ursula J.

    1999-01-01

    The growth of protein crystals is important for determination of their three-dimensional structure, which relates to their biochemical functions and to the practical goal of designing pharmaceuticals to modify that function. While many proteins have been successfully crystallized by a variety of methods, there is still limited understanding of the process of nucleation and growth of even the simplest proteins. Chicken egg-white lysozyme (CEWL) is readily crystallized under a variety of conditions, and studies underway at MSFC are designed to elucidate the mechanisms by which the crystals nucleate and grow. We have investigated the effect of buffer choice on the solubility, nucleation and growth of CEWL. CEWL was purified by dialysis against a .05M phosphate buffer and chromatographic separation from contaminants in a sepharose column. Solubility studies were made as a function of buffer concentration for phosphate and formate buffers, and the nucleation and growth of crystals at 10 C was studied as a function of pH for oxalate, succinate, formate, butyrate, carbonate, phosphate and acetate buffer solutions. The solubility data support the conclusion that there is a solubility minimum as a function of buffer concentration for amphiphilic molecules, while no minimum is observed for a phosphate buffer. Nucleation is suppressed at pH greater than pKa for all buffers except phosphate. The aspect ratio of the (110) faces is shown to be a function of crystal size, rather than pH.

  11. Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards

    NASA Astrophysics Data System (ADS)

    Novara, A.; Gristina, L.; Guaitoli, F.; Santoro, A.; Cerdà, A.

    2013-08-01

    When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out in the south coast of Sicily (Italy) to evaluate nitrate trends in a vineyard managed both conventionally and using two different cover crops (Triticum durum and Vicia sativa cover crop). A 10 m-wide buffer strip was seeded with Lolium perenne at the bottom of the vineyard. Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. Lolium perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. Vicia sativa cover crop management contributed with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduced the nitrate by 42% with and by 46% with a 9 m buffer strip. Thanks to catch crops, farmers can manage the N content and its distribution into the soil over the year, can reduced fertilizer wastage and reduce N pollution of surface and groundwater.

  12. Proteins contribute insignificantly to the intrinsic buffering capacity of yeast cytoplasm

    SciTech Connect

    Poznanski, Jaroslaw; Szczesny, Pawel; Ruszczynska, Katarzyna; Zielenkiewicz, Piotr; Paczek, Leszek

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer We predicted buffering capacity of yeast proteome from protein abundance data. Black-Right-Pointing-Pointer We measured total buffering capacity of yeast cytoplasm. Black-Right-Pointing-Pointer We showed that proteins contribute insignificantly to buffering capacity. -- Abstract: Intracellular pH is maintained by a combination of the passive buffering of cytoplasmic dissociable compounds and several active systems. Over the years, a large portion of and possibly most of the cell's intrinsic (i.e., passive non-bicarbonate) buffering effect was attributed to proteins, both in higher organisms and in yeast. This attribution was not surprising, given that the concentration of proteins with multiple protonable/deprotonable groups in the cell exceeds the concentration of free protons by a few orders of magnitude. Using data from both high-throughput experiments and in vitro laboratory experiments, we tested this concept. We assessed the buffering capacity of the yeast proteome using protein abundance data and compared it to our own titration of yeast cytoplasm. We showed that the protein contribution is less than 1% of the total intracellular buffering capacity. As confirmed with NMR measurements, inorganic phosphates play a crucial role in the process. These findings also shed a new light on the role of proteomes in maintaining intracellular pH. The contribution of proteins to the intrinsic buffering capacity is negligible, and proteins might act only as a recipient of signals for changes in pH.

  13. Analysis of Dicke Narrowing in Wall-Coated and Buffer-Gas-Filled Atomic Storage Cells,

    DTIC Science & Technology

    1986-04-01

    unshifted frequency. For the various reasons outlined the " particle in a box " analysis of motional narrowing in bufferless, wall-coated cells is...buffer gas or a wall, and consequently, one should not need two apparently distinct formalisms, buffer gas and particle in a box , to describe spectral line

  14. Simulation study on single event burnout in linear doping buffer layer engineered power VDMOSFET

    NASA Astrophysics Data System (ADS)

    Yunpeng, Jia; Hongyuan, Su; Rui, Jin; Dongqing, Hu; Yu, Wu

    2016-02-01

    The addition of a buffer layer can improve the device's secondary breakdown voltage, thus, improving the single event burnout (SEB) threshold voltage. In this paper, an N type linear doping buffer layer is proposed. According to quasi-stationary avalanche simulation and heavy ion beam simulation, the results show that an optimized linear doping buffer layer is critical. As SEB is induced by heavy ions impacting, the electric field of an optimized linear doping buffer device is much lower than that with an optimized constant doping buffer layer at a given buffer layer thickness and the same biasing voltages. Secondary breakdown voltage and the parasitic bipolar turn-on current are much higher than those with the optimized constant doping buffer layer. So the linear buffer layer is more advantageous to improving the device's SEB performance. Project supported by the National Natural Science Foundation of China (No. 61176071), the Doctoral Fund of Ministry of Education of China (No. 20111103120016), and the Science and Technology Program of State Grid Corporation of China (No. SGRI-WD-71-13-006).

  15. Investigation of solid-phase buffers for sulfur-oxidizing autotrophic denitrification.

    PubMed

    Sengupta, Sukalyan; Ergas, Sarina J; Lopez-Luna, Erika

    2007-12-01

    This paper investigates biological denitrification using autotrophic microorganisms that use elemental sulfur as an electron donor. In this process, for each gram of nitrate-nitrogen removed, approximately 4.5 g of alkalinity (as calcium carbonate) are consumed. Because denitrification is severely inhibited below pH 5.5, and alkalinity present in the influent wastewaters is less than the alkalinity consumed, an external buffer was needed to arrest any drop in pH from alkalinity consumption. A packed-bed bioreactor configuration is ideally suited to handle variations in flow and nitrate loading from decentralized wastewater treatment systems, as it is a passive system and thus requires minimal maintenance; therefore, a solid-phase buffer packed with the elemental sulfur in the bioreactor is most suitable. In this research, marble chips, limestone, and crushed oyster shells were tested as solid-phase buffers. Bench- and field-scale studies indicated that crushed oyster shell was the most suitable buffer based on (1) the rate of dissolution of buffer and the buffering agent released (carbonate, bicarbonate, or hydroxide), (2) the ability of the buffer surface to act as host for microbial attachment, (3) turbidity of the solution upon release of the buffering agent, and (4) economics.

  16. Explanation for the enhanced dissolution of silica column packing in high pH phosphate and carbonate buffers.

    PubMed

    Tindall, G W; Perry, R L

    2003-02-28

    It has been reported that at high pH, the rate of bonded phase packing degradation in methanol/water mobile phases is greater for carbonate and phosphate buffers than for amine buffers. This conclusion was based on buffer pH determined in the aqueous buffer before dilution with methanol. Changes in buffer species pKa, and therefore buffer pH, upon methanol dilution are consistent with the observed degradation results. Measurements of pH in the methanol/water solutions confirm that the carbonate and phosphate buffers were considerably more basic than the amine buffer, even though all the buffers were pH 10 before dilution with methanol. These results demonstrate that it can be misleading to extrapolate aqueous pH data to partially aqueous solutions. Measurements of pH in the mixed solvent provide more reliable predictions of column and sample stability.

  17. Statistical evaluation of effects of riparian buffers on nitrate and ground water quality

    USGS Publications Warehouse

    Spruill, T.B.

    2000-01-01

    A study was conducted to statistically evaluate the effectiveness of riparian buffers for decreasing nitrate concentrations in ground water and for affecting other chemical constituents. Values for pH, specific conductance, alkalinity, dissolved organic carbon (DOC), silica, ammonium, phosphorus, iron, and manganese at 28 sites in the Contentnea Creek Basin were significantly higher (p 20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dssolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dissolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (<20 yr) discharging ground water samples from buffer and nonbuffer areas indicated significantly higher specific conductance, calcium, chloride, and nitrate nitrogen in nonbuffer areas. Riparian buffers along streams can affect the composition of the hyporheic zone by providing a source of organic carbon to the streambed, which creates reducing geochemical conditions that consequently can affect the chemical quality of old ground water discharging through it. Buffer zones between agricultural fields and streams facilitate dilution of conservative chemical constituents in young ground water that originate from fertilizer applications and also allow denitrification in ground water by providing an adequate source of organic carbon generated by vegetation in the buffer zone. Based on the median chloride and nitrate values for young ground water in the Contentnea Creek Basin, nitrate was 95% lower in buffer areas compared with nonbuffer areas, with a 30 to 35% reduction

  18. Randomised control trial of pH buffered lignocaine with adrenaline in outpatient operations.

    PubMed

    Masters, J E

    1998-07-01

    Bicarbonate buffering of local anaesthetics is known to significantly decrease the pain of their administration and yet few practising surgeons do so. A double-blind randomised cross-over clinical trial was conducted to confirm the practicality and efficacy of bicarbonate buffering of lignocaine with adrenaline in the setting of a busy local anaesthetic operating theatre. 40 patients received either buffered or control local anaesthetic solutions in equivalent sites on opposite sides of the body. The pain of each injection was rated from 0 (no pain) to 10 (extreme pain). The mean pain score for the buffered solution was significantly lower than the control solution (3.06 vs 4.34, P = 0.002). Bicarbonate buffering of lignocaine with adrenaline is effective, inexpensive and simple; its widespread use should be encouraged.

  19. Propagation of misfit dislocations from buffer/Si interface into Si

    DOEpatents

    Liliental-Weber, Zuzanna; Maltez, Rogerio Luis; Morkoc, Hadis; Xie, Jinqiao

    2011-08-30

    Misfit dislocations are redirected from the buffer/Si interface and propagated to the Si substrate due to the formation of bubbles in the substrate. The buffer layer growth process is generally a thermal process that also accomplishes annealing of the Si substrate so that bubbles of the implanted ion species are formed in the Si at an appropriate distance from the buffer/Si interface so that the bubbles will not migrate to the Si surface during annealing, but are close enough to the interface so that a strain field around the bubbles will be sensed by dislocations at the buffer/Si interface and dislocations are attracted by the strain field caused by the bubbles and move into the Si substrate instead of into the buffer epi-layer. Fabrication of improved integrated devices based on GaN and Si, such as continuous wave (CW) lasers and light emitting diodes, at reduced cost is thereby enabled.

  20. 3D Frame Buffers For Interactive Analysis Of 3D Data

    NASA Astrophysics Data System (ADS)

    Hunter, Gregory M.

    1984-10-01

    Two-dimensional data such as photos, X rays, various types of satellite images, sonar, radar, seismic plots, etc., in many cases must be analyzed using frame buffers for purposes of medical diagnoses, crop estimates, mineral exploration, and so forth. In many cases the same types of sensors used to gather such samples in two dimensions can gather 3D data for even more effective analysis. Just as 2D arrays of data can be analyzed using frame buffers, three-dimensional data can be analyzed using SOLIDS-BUFFEPmemories. Image processors deal with samples from two-dimensional arrays, and are based on frame buffers. The SOLIDS PROCESSOR system, deals with samples from a three-dimensional volume, or solid, and is based on a 3D frame buffer. This paper focuses upon the SOLIDS-BUFFER system, as used in the INSIGHT SOLIDS-PROCESSOR system from Phoenix Data Systems.

  1. Buffer layer investigations on MFIS capacitors consisting of ferroelectric poly[vinylidene fluoride trifluoroethylene

    NASA Astrophysics Data System (ADS)

    Henkel, K.; Seime, B.; Paloumpa, I.; Müller, K.; Schmeißer, D.

    2010-02-01

    In this paper we present capacitance-voltage (CV) measurements on metal-ferroelectric-insulator-semiconductor (MFIS) capacitors with poly[vinylidene fluoride trifluoroethylene] (P[VDF/TrFE] as ferroelectric layer and SiO2, Al2O3 and HfO2 as buffering insulator layer. In order to discuss our data in a quantitative manner we perform fits to the data based on a model proposed by Miller and McWorther. The improvement of the polarization values and subsequently its effect on the hysteresis of the CV curve by the successive shrinking of the buffer layer thickness and the following choice of a high-k buffer material is demonstrated. Our data underline that a saturated polarization of P[VDF/TrFE] cannot be controlled with a SiO2 buffer layer and the insertion of a high-k buffer layer is essential for further improvements of the characteristics of MFIS stacks.

  2. Method of deforming a biaxially textured buffer layer on a textured metallic substrate and articles therefrom

    DOEpatents

    Lee, Dominic F.; Kroeger, Donald M.; Goyal, Amit

    2000-01-01

    The present invention provides methods and biaxially textured articles having a deformed epitaxial layer formed therefrom for use with high temperature superconductors, photovoltaic, ferroelectric, or optical devices. A buffer layer is epitaxially deposited onto biaxially-textured substrates and then mechanically deformed. The deformation process minimizes or eliminates grooves, or other irregularities, formed on the buffer layer while maintaining the biaxial texture of the buffer layer. Advantageously, the biaxial texture of the buffer layer is not altered during subsequent heat treatments of the deformed buffer. The present invention provides mechanical densification procedures which can be incorporated into the processing of superconducting films through the powder deposit or precursor approaches without incurring unfavorable high-angle grain boundaries.

  3. A 4H Silicon Carbide Gate Buffer for Integrated Power Systems

    SciTech Connect

    Ericson, N; Frank, S; Britton, C; Marlino, L; Ryu, SH; Grider, D; Mantooth, A; Francis, M; Lamichhane, R; Mudholkar, M; Shepherd, P; Glover, M; Valle-Mayorga, J; McNutt, T; Barkley, A; Whitaker, B; Cole, Z; Passmore, B; Lostetter, A

    2014-02-01

    A gate buffer fabricated in a 2-mu m 4H silicon carbide (SiC) process is presented. The circuit is composed of an input buffer stage with a push-pull output stage, and is fabricated using enhancement mode N-channel FETs in a process optimized for SiC power switching devices. Simulation and measurement results of the fabricated gate buffer are presented and compared for operation at various voltage supply levels, with a capacitive load of 2 nF. Details of the design including layout specifics, simulation results, and directions for future improvement of this buffer are presented. In addition, plans for its incorporation into an isolated high-side/low-side gate-driver architecture, fully integrated with power switching devices in a SiC process, are briefly discussed. This letter represents the first reported MOSFET-based gate buffer fabricated in 4H SiC.

  4. Thermophysical properties of carboxylic and amino acid buffers at subzero temperatures: relevance to frozen state stabilization.

    PubMed

    Sundaramurthi, Prakash; Suryanarayanan, Raj

    2011-06-02

    Macromolecules and other thermolabile biologicals are often buffered and stored in frozen or dried (freeze-dried) state. Crystallization of buffer components in frozen aqueous solutions and the consequent pH shifts were studied in carboxylic (succinic, malic, citric, tartaric acid) and amino acid (glycine, histidine) buffers. Aqueous buffer solutions were cooled from room temperature (RT) to -25 °C and the pH of the solution was measured as a function of temperature. The thermal behavior of frozen solutions was investigated by differential scanning calorimetry (DSC), and the crystallized phases were identified by X-ray diffractometry (XRD). Based on the solubility of the neutral species of each buffer system over a range of temperatures, it was possible to estimate its degree of supersaturation at the subambient temperature of interest. This enabled us to predict its crystallization propensity in frozen systems. The experimental and the predicted rank orderings were in excellent agreement. The malate buffer system was robust with no evidence of buffer component crystallization and hence negligible pH shift. In the citrate and tartrate systems, at initial pH < pK(a)(2), only the most acidic buffer component (neutral form) crystallized on cooling, causing an increase in the freeze-concentrate pH. In glycine buffer solutions, when the initial pH was ∼3 units < isoelectric pH (pI = 5.9), β-glycine crystallization caused a small decrease in pH, while a similar effect but in the opposite direction was observed when the initial pH was ∼3 units > pI. In the histidine buffer system, depending on the initial pH, either histidine or histidine HCl crystallized.

  5. Toward an in vivo dissolution methodology: a comparison of phosphate and bicarbonate buffers.

    PubMed

    Sheng, Jennifer J; McNamara, Daniel P; Amidon, Gordon L

    2009-01-01

    The purpose of this research was to evaluate the difference between the pharmaceutical phosphate buffers and the gastrointestinal bicarbonates in dissolution of ketoprofen and indomethacin, to illustrate the dependence of buffer differential on biopharmaceutical properties of BCS II weak acids, and to recommend phosphate buffers equivalent to bicarbonates. The intrinsic dissolution rates of ketoprofen and indomethacin were experimentally measured using a rotating disk method at 37 degrees C in USP SIF/FaSSIF and various concentrations of bicarbonates. Theoretical models including an improved reaction plane model and a film model were applied to estimate the surrogate phosphate buffers equivalent to the bicarbonates. Experimental results show that the intrinsic dissolution rates of ketoprofen and indomethacin in USP and FaSSIF phosphate buffers are 1.5-3.0 times that in the 15 mM bicarbonates. Theoretical analysis demonstrates that the buffer differential is largely dependent on the drug pK(a) and second on solubility, and weakly dependent on the drug diffusivity. Further, in accordance with the drug pK(a), solubility and diffusivity, a simple phosphate surrogate was proposed to match an average bicarbonate value (15 mM) of the upper gastrointestinal region. Specifically, phosphate buffers of 13-15 mM and 3-4 mM were recommended for ketoprofen and indomethacin, respectively. For both ketoprofen and indomethacin, the intrinsic dissolution using the phosphate surrogate buffers closely approximated the 15 mM bicarbonate buffer. This work demonstrates the substantial difference between pharmaceutical phosphates and physiological bicarbonates in determining the drug intrinsic dissolution rates of BCS II weak acids, such as ketoprofen and indomethacin. Surrogate phosphates were recommended in order to closely reflect the in vivo dissolution of ketoprofen and indomethacin in gastrointestinal bicarbonates, which has significant implications for defining buffer systems for

  6. New MBE buffer for micron- and quarter-micron-gateGaAs MESFETs

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A new buffer layer has been developed that eliminates backgating in GaAs MESFETs and substantially reduces short-channel effects in GaAs MESFETs with 0.27-micron-long gates. The new buffer is grown by molecular beam epitaxy (MBE) at a substrate temperature of 200 C using Ga and As sub 4 beam fluxes. The buffer is crystalline, highly resistive, optically inactive, and can be overgrown with high quality GaAs. GaAs MESFETs with a gate length of 0.27 microns that incorporate the new buffer show improved dc and RF properties in comparison with a similar MESFET with a thin undoped GaAs buffer. To demonstrate the backgating performance improvement afforded by the new buffer, MESFETs were fabricated using a number of different buffer layers and structures. A schematic cross section of the MESFET structure used in this study is shown. The measured gate length, gate width, and source-drain spacing of this device are 2,98, and 5.5 microns, respectively. An ohmic contact, isolated from the MESFET by mesa etching, served as the sidegate. The MESFETs were fabricated in MBE n-GaAs layers grown on the new buffer and also in MBE n-GaAs layers grown on buffer layers of undoped GaAs, AlGaAs, and GaAs/AlGaAs superlattices. All the buffer layers were grown by MBE and are 2 microns thick. The active layer is doped to approximately 2 x 10 to the 17th/cu cm with silicon and is 0.3 microns thick.

  7. Effects of buffer concentration on voltage-gated H+ currents: does diffusion limit the conductance?

    PubMed Central

    DeCoursey, T E; Cherny, V V

    1996-01-01

    The single-channel proton conductance of the voltage-gated H(+)-selective channel, like that of the F0 component of the H(+)-ATPase, is nearly constant over a wide range of pH encompassing the physiological range. To examine the possible contributions of buffer diffusion and buffer-channel proton transfer reactions to this phenomenon, the effects of buffer concentration on voltage-activated H+ currents were explored in voltage-clamped rat alveolar epithelial cells. Changes in the external buffer concentration ([B]o), evaluated using the whole-cell configuration, had only small effects on H+ currents (IH). Lowering [B]o from 100 to 1 mM did not alter the voltage-activation curve or reversal potential (Vrev) but reduced IH, typically by 10-30%. Changes in internal buffer concentration ([B]i), examined in inside-out patches, usually altered IH more distinctly and subtly changed the kinetics. Overall, the effects of changing buffer concentration were small and subtle. The maximum attenuation of the single-channel H+ current at 1 mM buffer was estimated to be approximately 20% at either mouth of the H+ channel. Therefore, the rate-determining step in H+ permeation is neither deprotonation of buffer at the inner mouth of the channel nor protonation of buffer at the external surface. Evidently the rate of H+ permeation through the channel is itself small enough that diffusion of buffer in bulk solution does not directly limit the conductance significantly. PMID:8804602

  8. Two New Nuclear Isolation Buffers for Plant DNA Flow Cytometry: A Test with 37 Species

    PubMed Central

    Loureiro, João; Rodriguez, Eleazar; Doležel, Jaroslav; Santos, Conceição

    2007-01-01

    Background and Aims After the initial boom in the application of flow cytometry in plant sciences in the late 1980s and early 1990s, which was accompanied by development of many nuclear isolation buffers, only a few efforts were made to develop new buffer formulas. In this work, recent data on the performance of nuclear isolation buffers are utilized in order to develop new buffers, general purpose buffer (GPB) and woody plant buffer (WPB), for plant DNA flow cytometry. Methods GPB and WPB were used to prepare samples for flow cytometric analysis of nuclear DNA content in a set of 37 plant species that included herbaceous and woody taxa with leaf tissues differing in structure and chemical composition. The following parameters of isolated nuclei were assessed: forward and side light scatter, propidium iodide fluorescence, coefficient of variation of DNA peaks, quantity of debris background, and the number of particles released from sample tissue. The nuclear genome size of 30 selected species was also estimated using the buffer that performed better for a given species. Key Results In unproblematic species, the use of both buffers resulted in high quality samples. The analysis of samples obtained with GPB usually resulted in histograms of DNA content with higher or similar resolution than those prepared with the WPB. In more recalcitrant tissues, such as those from woody plants, WPB performed better and GPB failed to provide acceptable results in some cases. Improved resolution of DNA content histograms in comparison with previously published buffers was achieved in most of the species analysed. Conclusions WPB is a reliable buffer which is also suitable for the analysis of problematic tissues/species. Although GPB failed with some plant species, it provided high-quality DNA histograms in species from which nuclear suspensions are easy to prepare. The results indicate that even with a broad range of species, either GPB or WPB is suitable for preparation of high

  9. Dynamics and mitigation of six pesticides in a "Wet" forest buffer zone.

    PubMed

    Passeport, Elodie; Richard, Benjamin; Chaumont, Cédric; Margoum, Christelle; Liger, Lucie; Gril, Jean-Joël; Tournebize, Julien

    2014-04-01

    Pesticide pollution is one of the main current threats on water quality. This paper presents the potential and functioning principles of a "Wet" forest buffer zone for reducing concentrations and loads of glyphosate, isoproturon, metazachlor, azoxystrobin, epoxiconazole, and cyproconazole. A tracer injection experiment was conducted in the field in a forest buffer zone at Bray (France). A fine time-scale sampling enabled to illustrate that interactions between pesticides and forest buffer substrates (soil and organic-rich litter layer), had a retarding effect on molecule transfer. Low concentrations were observed for all pesticides at the forest buffer outlet thus demonstrating the efficiency of "Wet" forest buffer zone for pesticide dissipation. Pesticide masses injected in the forest buffer inlet directly determined concentration peaks observed at the outlet. Rapid and partially reversible adsorption was likely the major process affecting pesticide transfer for short retention times (a few hours to a few days). Remobilization of metazachlor, isoproturon, desmethylisoproturon, and AMPA was observed when non-contaminated water flows passed through the forest buffer. Our data suggest that pesticide sorption properties alone could not explain the complex reaction mechanisms that affected pesticide transfer in the forest buffer. Nevertheless, the thick layer of organic matter litter on the top of the forest soil was a key parameter, which enhanced partially reversible sorption of pesticide, thus retarded their transfer, decreased concentration peaks, and likely increased degradation of the pesticides. Consequently, to limit pesticide pollution transported by surface water, the use of already existing forest areas as buffer zones should be equally considered as the most commonly implemented grass buffer strips.

  10. Sediment Buffering and Transport in the Holocene Indus River System

    NASA Astrophysics Data System (ADS)

    Clift, P. D.; Giosan, L.; Henstock, T.; Tabrez, A. R.; Vanlaningham, S.; Alizai, A. H.; Limmer, D. R.; Danish, M.

    2009-12-01

    Submarine fans are the largest sediment bodies on Earth and potentially hold records of erosion that could be used to assess the response of continents to changing climate in terms of both physical erosion and chemical weathering. However, buffering between the mountain sources and the abyssal plain may make detailed correlation of climate and erosion records difficult. We investigated the nature of sediment transport in the Indus drainage in SW Asia. Through trenching in the flood plain, drilling in the delta and new seismic and coring data from the shelf and canyon we can now constrain sediment transport from source to sink since the Last Glacial Maximum (LGM). The Indus was affected by intensification of the summer monsoon during the Early Holocene and subsequent weakening since ca. 8 ka. Sediment delivery to the delta was very rapid at 12-8 ka, but slowed along with the weakening monsoon. At the LGM erosion in the Karakoram dominated the supply of sandy material, while the proportion of Lesser Himalayan flux increased with strengthening summer rainfall after 12 ka. Total load also increased at that time. Since 5 ka incision of rivers into the upper parts of the flood plain has reworked Lower Holocene sediments, although the total flux slowed. Coring in the Indus canyon shows that sediment has not reached the lower canyon since ca. 7 ka, but that sedimentation has recently been very rapid in the head of the canyon. We conclude that variations in sealevel and terrestrial climate have introduced a lag of at least 7 k.y. into the deep sea fan record and that monsoon strength is a primary control on whether sediment is stored or released in the flood plain.

  11. Gray wolves as climate change buffers in Yellowstone.

    PubMed

    Wilmers, Christopher C; Getz, Wayne M

    2005-04-01

    Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate and regional predator assemblages. In Yellowstone National Park, winter conditions and reintroduced gray wolves (Canis lupus) together determine the availability of winter carrion on which numerous scavenger species depend for survival and reproduction. As climate changes in Yellowstone, therefore, scavenger species may experience a dramatic reshuffling of food resources. As such, we analyzed 55 y of weather data from Yellowstone in order to determine trends in winter conditions. We found that winters are getting shorter, as measured by the number of days with snow on the ground, due to decreased snowfall and increased number of days with temperatures above freezing. To investigate synergistic effects of human and climatic alterations of species interactions, we used an empirically derived model to show that in the absence of wolves, early snow thaw leads to a substantial reduction in late-winter carrion, causing potential food bottlenecks for scavengers. In addition, by narrowing the window of time over which carrion is available and thereby creating a resource pulse, climate change likely favors scavengers that can quickly track food sources over great distances. Wolves, however, largely mitigate late-winter reduction in carrion due to earlier snow thaws. By buffering the effects of climate change on carrion availability, wolves allow scavengers to adapt to a changing environment over a longer time scale more commensurate with natural processes. This study illustrates the importance of restoring and maintaining intact food chains in the face of large-scale environmental perturbations such as climate change.

  12. Physical activity buffers fatigue only under low chronic stress.

    PubMed

    Strahler, Jana; Doerr, Johanna M; Ditzen, Beate; Linnemann, Alexandra; Skoluda, Nadine; Nater, Urs M

    2016-09-01

    Fatigue is one of the most commonly reported complaints in the general population. As physical activity (PA) has been shown to have beneficial effects, we hypothesized that everyday life PA improves fatigue. Thirty-three healthy students (21 women, 22.8 ± 3.3 years, 21.7 ± 2.3 kg/m(2)) completed two ambulatory assessment periods. During five days at the beginning of the semester (control condition) and five days during final examination preparation (examination condition), participants repeatedly reported on general fatigue (awakening, 10 am, 2 pm, 6 pm and 9 pm) by means of an electronic diary, collected saliva samples for the assessment of cortisol and α-amylase immediately after providing information on fatigue and wore a triaxial accelerometer to continuously record PA. Self-perceived chronic stress was assessed as a moderator. Using hierarchical linear modeling, including PA, condition (control vs. examination), sex and chronic stress as predictors, PA level during the 15 min prior to data entry did not predict momentary fatigue level. Furthermore, there was no effect of condition. However, a significant cross-level interaction of perceived chronic stress with PA was observed. In fact, the (negative) relationship between PA and fatigue was stronger in those participants with less chronic stress. Neither cortisol nor α-amylase was significantly related to physical activity or fatigue. Our study showed an immediate short-term buffering effect of everyday life PA on general fatigue, but only when experiencing lower chronic stress. There seems to be no short-term benefit of PA in the face of higher chronic stress. These findings highlight the importance of considering chronic stress when evaluating the effectiveness of PA interventions in different target populations, in particular among chronically stressed and fatigued subjects.

  13. Ca²+ buffering at a drosophila larval synaptic terminal.

    PubMed

    He, Tao; Lnenicka, Gregory A

    2011-07-01

    A quantitative analysis of Ca²+ dynamics requires knowledge of the Ca²+-binding ratio (κ(S) ); this has not been measured at Drosophila synaptic terminals or any invertebrate synaptic terminal. We measured κ(S) at a Ib motor terminal in Drosophila larvae comparing single-AP Ca²+ transients in synaptic terminals that contained varying concentrations of the Ca²+ indicator, Oregon Green 488 BAPTA-1 (OGB-1). Using a linear single-compartment model, κ(S) was calculated based upon the effect of [OGB-1] on the time constant (τ(decay) ) for the decay of intracellular free Ca²+ concentration ([Ca²+](i)). This gave a κ(S) of 77 indicating that nearly 99% of entering Ca²+ is immediately bound by endogenous fast Ca²+ buffers. Extrapolation to zero [OGB-1] gave a τ(decay) of 46 ms and a Ca²+-removal rate constant of 1641 s⁻¹ for single APs. We calculated that a single AP produced an increase in [Ca²+](i) of 196 nM and an increase in the total intracellular [Ca²+](free + bound) of 15.3 μM for measurements made in 1.0 mM external Ca²+. The increase in [Ca²+](i) for AP trains was 185 nM/ 10 Hz; this gave a Ca²+ extrusion rate constant of 827 s⁻¹, which likely reflects the activity of the plasma membrane Ca²+ ATPase. Experiments were performed to examine the effect of altering external Ca²+ or Mg²+ on Ca²+ influx at these terminals.

  14. Highly smooth Nb surfaces fabricated by buffered electropolishing

    SciTech Connect

    Andy T. Wu; John Mammossor; H. Phillips; Jean Delayen; Charles Reece; Amy Wilkerson; David Smith; Robert Ike

    2005-05-01

    It is demonstrated that highly smooth Nb surfaces can be obtained through Buffered ElectroPolishing (BEP) employing an electrolyte consisting of lactic, sulfuric, and hydrofluoric acids. Parameters that control the polishing process are optimized to achieve the smoothest surface finish with the help of surface observations using a scanning electron microscope and a Metallographic Optical Microscope (MOM). The polishing rate of BEP is determined to be 0.646 {micro}m/min that is much higher than 0.381 {micro}m/min achieved by the conventional ElectroPolishing (EP) process widely used in the Superconducting Radio Frequency (SRF) community. A high precision and large scan area 3-D profilometer is used to view morphology of the treated Nb surfaces. Statistical data, such as, rms, total indicator runout, and arithmetic mean deviation of the Nb surfaces are extracted from the profilometer images. It is found that Nb surfaces treated by BEP are an order of magnitude smoother than those treated by the optimized EP process. The chemical composition of the Nb surfaces after BEP is analyzed by static and dynamic Secondary Ion Mass Spectrometer (SIMS) systems. Cracking patterns of the Nb surfaces under different primary ion sources of Ga{sup +}, Au{sup +}, and Ar{sup +} are reported. The depth profile of the surface niobium oxides is studied through continuously monitoring niobium and its relevant oxides' peaks as a function of time. Dynamic SIMS results imply that the surface oxide structure of Nb may be more complicated than what usually believed and can be inhomogeneous. Preliminary results of BEP on Nb SRF single cell cavities and half-cells are reported. It is shown that smooth and bright surfaces can be obtained in 30 minutes when the electric field inside a SRF cavity is uniform during a BEP process. This study reveals that BEP is a highly promising technique for surface treatment on Nb SRF cavities to be used in particle accelerators.

  15. Thermal Inactivation of Staphylococcal Enterotoxin B in Veronal Buffer

    PubMed Central

    Read, R. B.; Bradshaw, J. G.

    1966-01-01

    The times and temperatures required to inactivate staphylococcal enterotoxin B were studied by use of the double-gel-diffusion technique to assay enterotoxin. Enterotoxin B (99 +% pure) was suspended in 0.04 M Veronal buffer, dispensed into borosilicate vials, and the vials were sealed and heated in an oil bath. An amount of 30 μg/ml of this toxin was reduced to less than 0.7 μg/ml in 103.0, 87.1, 70.5, 57.2, 39.1, 27.6, 16.4, and 12.0 min, respectively, at temperatures of 96, 99, 101.7, 104.4, 110, 115.6, 121, and 126.7 C. The end point for enterotoxin inactivation by gel diffusion was identical to that by intravenous injection of cats. Limited studies with crude enterotoxin B showed that the crude preparation was slightly more thermostable. The respective D values of crude and purified enterotoxin B were 64.5 and 52.3, 40.5 and 34.4, 29.7 and 23.5, 18.8 and 16.6, and 11.4 and 9.9 min at temperatures of 99, 104.4, 110, 115.6, and 121 C. The z value for purified enterotoxin B was 32.4 C. The experimental activation energy was 20,700 cal/g mole, standard enthalpy of activation at 120 C was 19,900 cal/g mole, standard entropy of activation at 120 C was -21.4 cal/g mole K, and the standard free energy of activation at 120 C was 28,200 cal/g mole. PMID:4958146

  16. Buffering PV output during cloud transients with energy storage

    NASA Astrophysics Data System (ADS)

    Moumouni, Yacouba

    Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis provides a detailed analysis with appropriate Matlab codes to put onto the grid during the day time a constant amount of power on one hand and on the other, shift the less valuable off-peak electricity to the on-peak time, i.e. between 1pm to 7pm, where the electricity price is much better. In this study, a range of base constant power levels were assumed including 15kW, 20kW, 21kW, 22kW, 23kW, 24kW and 25kW. The hypothesis based on an iterative solution was that the capacity of the battery was increased by steps of 5 while the base supply was decreased by the same step size until satisfactorily results were achieved. Hence, it turned out with the chosen battery capacity of 54kWh coupled to the data from the Amonix CPV 7700 unit for Las Vegas for a 3-month period, it was found that 20kW was the largest constant load the system can supply uninterruptedly to the utility company. Simulated results are presented to show the feasibility of the proposed scheme.

  17. Photosynthetic activity buffers ocean acidification in seagrass meadows

    NASA Astrophysics Data System (ADS)

    Hendriks, I. E.; Olsen, Y. S.; Ramajo, L.; Basso, L.; Steckbauer, A.; Moore, T. S.; Howard, J.; Duarte, C. M.

    2014-01-01

    Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5-12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range ΩAr within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, ΩAr and carbonate deposition. Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.

  18. Regulation of c-Myc mRNA by L11 in Response to UV and Gamma irradiation

    DTIC Science & Technology

    2011-10-01

    in lysis buffer consisting of 50 mM Tris-HCl (pH 8.0), 0.5% Nonidet P - 40 , 5 mM EDTA, 150 mM NaCl, 1 mM phenylmethylsulfonyl fluoride (PMSF), 1 mM...buffer (PLB) (100 mM KCl, 5 mM MgCl2, 10 mM HEPES [pH 7.0], 0.5% Nonidet P - 40 , 1 mM DTT, 100 U of RNase inhibitor/ml) supplemented with 20 mM EDTA and...supernatants were then diluted (1:10 [vol/vol]) in NT2 buffer (50 mM Tris [pH 7.4], 150 mM NaCl, 1 mM MgCl2, 0.05% Nonidet P - 40 , 1 mM DTT, 100 U of RNase

  19. [Influence of buffer solutions on the performance of microbial fuel cell electricity generation].

    PubMed

    Qiang, Lin; Yuan, Lin-jiang; Ding, Qing

    2011-05-01

    Microbial fuel cell (MFC) is a potential green technology due to its application in wastewater treatment and renewable energy generation. Phosphate buffer solution (PBS) has been commonly used in MFC studies to maintain a suitable pH for electricity generating bacteria and/or to increase the solution conductivity. However, it has some drawbacks using PBS in MFC: One is that the addition of a high concentration of phosphate buffer in MFCs is expensive, especially for the application in wastewater treatment; the other is that phosphates can contribute to the eutrophication conditions of water bodies if the effluents are discharged without the removal of phosphates. By adding PBS buffer as the comparison, the study investigated the effect of borax buffer and in the absence of buffer on the performance of electrical power, coulomb efficiency and effluent pH. 200 mmol/L PBS was the best, conductivity was 1.973 mS/cm,the maximum power density was 36.4 mW/m2 and the maximum coulomb efficiency was 2.92%, effluent pH was almost at (7.00 +/- 0.05). 100 mmol/L borax buffer solution, conductivity was 1.553 mS/cm; the maximum power density was 26.2 mW/m2 coulomb efficiency of 6.26%, which was 2.14 times to PBS and greatly increased the electron recovery efficiency with the effluent pH was (7.35 +/- 0.05). While free buffer solution conductivity was 0.314 mS/cm, maximum power density was 27.64 mW/m2; coulomb efficiency was 2.82% and the effluent pH of approximately 7.43. The electrolyte which in absence of buffer solution conductivity was 1/6 of adding PBS buffer, 1/5 of borax buffer, while its power density lower 8.76 mW/mr2 than adding PBS and higher 1.24 mW/m2 than borax buffer. The results showed that adding the suitable concentration of borax buffer may improve the electron recovery efficiency and under batch conditions, MFC run successfully without adding buffer solution to MFC.

  20. Stability of buffer-free freeze-dried formulations: A feasibility study of a monoclonal antibody at high protein concentrations.

    PubMed

    Garidel, Patrick; Pevestorf, Benjamin; Bahrenburg, Sven

    2015-11-01

    We studied the stability of freeze-dried therapeutic protein formulations over a range of initial concentrations (from 40 to 160 mg/mL) and employed a variety of formulation strategies (including buffer-free freeze dried formulations, or BF-FDF). Highly concentrated, buffer-free liquid formulations of therapeutic monoclonal antibodies (mAbs) have been shown to be a viable alternative to conventionally buffered preparations. We considered whether it is feasible to use the buffer-free strategy in freeze-dried formulations, as an answer to some of the known drawbacks of conventional buffers. We therefore conducted an accelerated stability study (24 weeks at 40 °C) to assess the feasibility of stabilizing freeze-dried formulations without "classical" buffer components. Factors monitored included pH stability, protein integrity, and protein aggregation. Because the protein solutions are inherently self-buffering, and the system's buffer capacity scales with protein concentration, we included highly concentrated buffer-free freeze-dried formulations in the study. The tested formulations ranged from "fully formulated" (containing both conventional buffer and disaccharide stabilizers) to "buffer-free" (including formulations with only disaccharide lyoprotectant stabilizers) to "excipient-free" (with neither added buffers nor stabilizers). We evaluated the impacts of varying concentrations, buffering schemes, pHs, and lyoprotectant additives. At the end of 24 weeks, no change in pH was observed in any of the buffer-free formulations. Unbuffered formulations were found to have shorter reconstitution times and lower opalescence than buffered formulations. Protein stability was assessed by visual inspection, sub-visible particle analysis, protein monomer content, charge variants analysis, and hydrophobic interaction chromatography. All of these measures found the stability of buffer-free formulations that included a disaccharide stabilizer comparable to buffer

  1. New pH-buffering system for media utilized during gamete and embryo manipulations for assisted reproduction.

    PubMed

    Swain, Jason E; Pool, Thomas B

    2009-06-01

    Maintenance of stable pH is important for optimizing gamete and embryo culture. One method to stabilize pH entails using zwitterionic buffers in IVF handling media used outside the laboratory incubator. Current handling media utilize single buffers, such as MOPS or HEPES. However, the use of a single buffer limits the ability to adjust the range of buffering capacity. Furthermore, changes in temperature alter buffering of these compounds. Therefore, traditional IVF handling media utilizing a single buffer may not provide ideal pH buffering. This study reports that combining multiple buffers, such as HEPES, MOPS and DIPSO, into a single medium in various ratios gives the ability to shift the effective buffering range to cover a specific pH. Additionally, by combining various buffers, it is possible to expand pH buffering over a range of temperatures, while simultaneously reducing the absolute concentration of individual buffers, thereby reducing or alleviating toxicity concerns. This report verifies that DIPSO, MOPS and HEPES, and their combinations, support embryo development. Therefore, utilization of bi- and tri-buffered media, containing a mixture of HEPES, MOPS or DIPSO, offers advantages compared with media containing HEPES or MOPS alone, and may be used for procedures such as oocyte retrieval, intracytoplasmic sperm injection, embryo transfer and cryopreservation.

  2. Reprogrammable read only variable threshold transistor memory with isolated addressing buffer

    DOEpatents

    Lodi, Robert J.

    1976-01-01

    A monolithic integrated circuit, fully decoded memory comprises a rectangular array of variable threshold field effect transistors organized into a plurality of multi-bit words. Binary address inputs to the memory are decoded by a field effect transistor decoder into a plurality of word selection lines each of which activates an address buffer circuit. Each address buffer circuit, in turn, drives a word line of the memory array. In accordance with the word line selected by the decoder the activated buffer circuit directs reading or writing voltages to the transistors comprising the memory words. All of the buffer circuits additionally are connected to a common terminal for clearing all of the memory transistors to a predetermined state by the application to the common terminal of a large magnitude voltage of a predetermined polarity. The address decoder, the buffer and the memory array, as well as control and input/output control and buffer field effect transistor circuits, are fabricated on a common substrate with means provided to isolate the substrate of the address buffer transistors from the remainder of the substrate so that the bulk clearing function of simultaneously placing all of the memory transistors into a predetermined state can be performed.

  3. Stream Community Structure: An Analysis of Riparian Forest Buffer Restoration in the Chesapeake Bay Watershed

    NASA Astrophysics Data System (ADS)

    Orzetti, L. L.; Jones, R. C.

    2005-05-01

    Forested riparian buffer zones have been proposed as an important aid in curtailing upland sources of pollution before they reach stream surface waters, and enhancing habitat for stream organisms. Our objective was to test the efficacy of restored forest riparian buffers along streams in the Chesapeake Bay watershed by examining the stream macrobenthic community structure. To test our hypothesis, we collected riffle benthic and water samples, and performed habitat evaluations at 30 stream sites in the mid-Atlantic Piedmont, ranging in buffer age from 0 to greater than 50 years of age. Results showed that habitat, water quality, and benthic macroinvertebrate metrics improved with age of restored buffer. Habitat scores were driven mostly by instream substrate availability and width and age of riparian buffer zones. Water quality parameters varied within buffer age groups depending age of surrounding forest vegetation. Benthic invertebrate taxa richness, % EPT, % Plecoptera, % Ephemeroptera, and the FBI all improved with age of buffer zone. Instream habitat quality was the greatest driver of benthic macroinvertebrate community diversity and health, and appeared to plateau within 10-15 years of restoration with noticeable improvements occurring within 5-10 years post restoration.

  4. The impact of buffer strips and stream-side grazing on small mammals in southwestern Wisconsin

    USGS Publications Warehouse

    Chapman, Erik W.; Ribic, C.A.

    2002-01-01

    The practice of continuously grazing cattle along streams has caused extensive degradation of riparian habitats. Buffer strips and managed intensive rotational grazing (MIRG) have been proposed to protect and restore stream ecosystems in Wisconsin. However, the ecological implications of a switch from traditional livestock management to MIRG or buffer strip establishment have not been investigated. Differences in small mammal communities associated with riparian areas on continuously grazed and MIRG pastures, as well as vegetative buffer strips adjacent to row crops, were investigated in southwestern Wisconsin during May-September 1997 and 1998. More species (mean of 6-7) were found on the buffer sites than on the pasture sites (mean of 2-5). Total small mammal abundance on buffer sites was greater than on the pastures as well: there were 3-5 times as many animals on the buffer sites compared to the pasture sites, depending on year. There were no differences in species richness or total abundance between MIRG and continuously grazed pastures in either year. Total small mammal abundance was greater near the stream than away from the stream, regardless of farm management practice but there were no differences in species richness. Buffer strips appear to support a particularly rich and abundant small mammal community. Although results did not detect a difference in small mammal use between pasture types, farm-wide implications of a conversion from continuous to MIRG styles of grazing may benefit small mammals indirectly by causing an increase in the prevalence of pasture in the agricultural landscape.

  5. Buffer architecture for biaxially textured structures and method of fabricating same

    DOEpatents

    Norton, David P.; Park, Chan; Goyal, Amit

    2004-04-06

    The invention relates to an article with an improved buffer layer architecture comprising a substrate having a metal surface, and an epitaxial buffer layer on the surface of the substrate. The epitaxial buffer layer comprises at least one of the group consisting of ZrO.sub.2, HfO.sub.2, and compounds having at least one of Ca and a rare earth element stabilizing cubic phases of ZrO.sub.2 and/or HfO.sub.2. The article can also include a superconducting layer deposited on the epitaxial buffer layer. The article can also include an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer. A method for preparing an epitaxial article comprises providing a substrate with a metal surface, depositing on the metal surface an epitaxial buffer layer comprising at least one material selected from the group consisting of ZrO.sub.2, HfO.sub.2, and compounds having at least one of Ca and a rare earth element stabilizing cubic phases of at least one of ZrO.sub.2 and HfO.sub.2. The epitaxial layer depositing step occurs in a vacuum with a background pressure of no more than 1.times.10.sup.-5 Torr. The method can further comprise depositing a superconducting layer on the epitaxial layer, and depositing an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer.

  6. Buffer salt effects in off-line coupling of capillary electrophoresis and mass spectrometry.

    PubMed

    Marák, Jozef; Stanová, Andrea

    2014-05-01

    In this work, the impact of buffer salts/matrix effects on the signal in direct injection MS with an electrospray interface (DI-ESI-MS) following pITP fractionation of the sample was studied. A range of buffers frequently used in CE analyses (pH 3-10) was prepared containing 10, 50, and 90% v/v of ACN, respectively. The sets of calibration solutions of cetirizine (an antihistaminic drug with an amphiprotic character) within a 0.05-2.0 mg/L concentration range were prepared in different buffers. The greatest enhancements in the MS signal (in terms of change in the slope of the calibration line) were obtained for the beta-alanine buffer (pH 3.5) in positive ionization and for the borate buffer (pH 9.2) in negative ionization, respectively. The procedure was successfully applied to the analysis of buserelin (a peptidic drug). The slope of the calibration line for solutions containing the beta-alanine buffer with 50% of ACN was 4 times higher than for water or urine, respectively. This study clearly demonstrates that the buffer salt/matrix effects in an offline combination of pITP and DI-ESI-MS can also play a positive role, as they can enhance the signal in MS. A similar influence of the above effects can also be presumed in the CE techniques combined on-line with ESI-MS.

  7. Rapid riparian buffer width and quality analysis using lidar in South Carolina

    NASA Astrophysics Data System (ADS)

    Akturk, Emre

    The importance of protecting water quality and aquatic resources are increasing because of harmful human impacts within and around waterways. Establishing or restoring functional riparian areas protect water quality and are a good mechanism to conserve aquatic systems, plants, and wildlife. Laser-based remote sensing technology offers a high resolution approach to both characterize and document changes in riparian buffer zones (RBZs). The objectives of this study were to build a model to calculate riparian buffer width on both sides of a stream using a LiDAR-derived slope variable, to classify riparian buffers and determine their quality, and to evaluate the appropriateness of using LiDAR in riparian buffer assessment. For this purpose, RBZs were delineated for Hunnicutt and King Creek, which are located in Oconee and Pickens counties, in South Carolina. Results show that LiDAR was effective in delineating required riparian buffer widths based on the topography slope of upstream areas, and to calculate the ratio of tree cover in those riparian buffer zones to qualify them. Furthermore, the riparian buffer assessment model that was created in this research has potential for use in different sites and different studies.

  8. The roles of buffer layer thickness on the properties of the ZnO epitaxial films

    NASA Astrophysics Data System (ADS)

    Tang, Kun; Huang, Shimin; Gu, Shulin; Zhu, Shunming; Ye, Jiandong; Xu, Zhonghua; Zheng, Youdou

    2016-12-01

    In this article, the authors have investigated the optimization of the buffer thickness for obtaining high-quality ZnO epi-films on sapphire substrates. The growth mechanism of the buffers with different thickness has been clearly revealed, including the initial nucleation and vertical growth, the subsequent lateral growth with small grain coalescence, and the final vertical growth along the existing larger grains. Overall, the quality of the buffer improves with increasing thickness except the deformed surface morphology. However, by a full-scale evaluation of the properties for the epi-layers, the quality of the epi-film is briefly determined by the surface morphology of the buffer, rather than the structural, optical, or electrical properties of it. The best quality epi-layer has been grown on the buffer with a smooth surface and well-coalescent grains. Meanwhile, due to the huge lattice mismatch between sapphire and ZnO, dislocations are inevitably formed during the growth of buffers. More importantly, as the film grows thicker, the dislocations may attracting other smaller dislocations and defects to reduce the total line energy and thus result in the formation of V-shape defects, which are connected with the bottom of the threading dislocations in the buffers. The V-defects appear as deep and large hexagonal pits from top view and they may act as electron traps which would affect the free carrier concentration of the epi-layers.

  9. Density measurements of potassium phosphate buffer from 4 to 45 degrees C.

    PubMed

    Schiel, John E; Hage, David S

    2005-01-30

    Potassium phosphate buffer is often used in methods such as equilibrium dialysis, high performance liquid chromatography (HPLC), and affinity capillary electrophoresis (ACE) for characterizing the binding of drugs and hormones with proteins or other ligands within the body. In these experiments, the buffer density is often approximated to be that of water and the concentrations of all reagents are assumed to be constant with temperature. However, some difference in density between phosphate buffer and water would be expected, and variations in this density could lead to significant changes in the concentrations of dissolved solutes with temperature. This, in turn, could affect the binding observed for a solute-ligand system in such a buffer. In this study, the densities of potassium phosphate buffers with concentrations up to 0.10M were measured at or near physiological pH for temperatures ranging from 4-45 degrees C. The general change in density versus temperature followed a quadratic equation, while the changes in density with concentration and pH followed a linear response. The results were used to formulate a general equation that could be used to calculate the density of potassium phosphate buffer at any pH, temperature, and concentration within the tested range. This equation and more specialized relationships developed in the temperature, concentration, and pH studies were found to give much greater accuracy in describing the density of these buffers versus a previous relationship developed for solutions containing only potassium dihydrogen phosphate.

  10. The Social Buffering of the Hypothalamic-Pituitary-Adrenocortical Axis in Humans: Developmental and Experiential Determinants

    PubMed Central

    Gunnar, Megan R.; Hostinar, Camelia E.

    2015-01-01

    Social buffering, a subset of social support, is the process through which the availability of a conspecific reduces the activity of stress-mediating neurobiological systems. While its role in coping and resilience is significant, we know little about its developmental history in humans. This brief review presents an integrative developmental account of the social buffering of hypothalamic-pituitary-adrenocortical (HPA) stress reactivity in humans, from infancy to adulthood. During infancy, parents are powerful stress-regulators for children, but child temperament also plays a role and interacts with parenting quality to predict the magnitude of stress responses to fear or pain stimuli. Recent work indicates that parental support remains a potent stress buffer into late childhood, but that it loses its effectiveness as a buffer of the HPA axis by adolescence. Puberty may be the switch that alters the potency of parental buffering. In Beginning in middle childhood, friends may serve as stress buffers, particularly when other peers are the source of stress. By adulthood romantic partners assume this protective role, though studies often reveal sex differences that are currently not well understood. Translational research across species will be critical for developing a mechanistic understanding of social buffering and the processes involved in developmental changes noted in this review. PMID:26230646

  11. GaAs buffer layer technique for vertical nanowire growth on Si substrate

    SciTech Connect

    Xu, Xiaoqing Parizi, Kokab B.; Huo, Yijie; Kang, Yangsen; Philip Wong, H.-S.; Li, Yang

    2014-02-24

    Gold catalyzed vapor-liquid-solid method is widely applied to III–V nanowire (NW) growth on Si substrate. However, the easy oxidation of Si, possible Si contamination in the NWs, high defect density in the NWs, and high sensitivity of the NW morphology to growth conditions largely limit its controllability. In this work, we developed a buffer layer technique by introducing a GaAs thin film with predefined polarity as a template. It is found that samples grown on these buffer layers all have high vertical NW yields in general, due to the single-orientation of the buffer layers. Low temperature buffer with smoother surface leads to highest yield of vertical NWs, while high temperature (HT) buffer with better crystallinity results in perfect NW quality. The defect-free property we observed here is very promising for optoelectronic device applications based on GaAs NW. Moreover, the buffer layers can eliminate Si contamination by preventing Si-Au alloy formation and by increasing the thickness of the Si diffusion barrier, thus providing more flexibility to vertical NW growth. The buffer layer technique we demonstrated here could be easily extended to other III-V on Si system for electronic and photonic applications.

  12. Read buffer optimizations to support compiler-assisted multiple instruction retry

    NASA Technical Reports Server (NTRS)

    Alewine, N. J.; Fuchs, W. K.; Hwu, W. M.

    1993-01-01

    Multiple instruction retry is a recovery mechanism for transient processor faults. We previously developed a compiler-assisted approach to multiple instruction ferry in which a read buffer of size 2N (where N represents the maximum instruction rollback distance) was used to resolve some data hazards while the compiler resolved the remaining hazards. The compiler-assisted scheme was shown to reduce the performance overhead and/or hardware complexity normally associated with hardware-only retry schemes. This paper examines the size and design of the read buffer. We establish a practical lower bound and average size requirement for the read buffer by modifying the scheme to save only the data required for rollback. The study measures the effect on the performance of a DECstation 3100 running ten application programs using six read buffer configurations with varying read buffer sizes. Two alternative configurations are shown to be the most efficient and differed depending on whether split-cycle-saves are assumed. Up to a 55 percent read buffer size reduction is achievable with an average reduction of 39 percent given the most efficient read buffer configuration and a variety of applications.

  13. Modeling early in situ wetting of a compacted bentonite buffer installed in low permeable crystalline bedrock

    NASA Astrophysics Data System (ADS)

    Dessirier, B.; Frampton, A.; Fransson, Å.; Jarsjö, J.

    2016-08-01

    The repository concept for geological disposal of spent nuclear fuel in Sweden and Finland is planned to be constructed in sparsely fractured crystalline bedrock and with an engineered bentonite buffer to embed the waste canisters. An important stage in such a deep repository is the postclosure phase following the deposition and the backfilling operations when the initially unsaturated buffer material gets hydrated by the groundwater delivered by the natural bedrock. We use numerical simulations to interpret observations on buffer wetting gathered during an in situ campaign, the Bentonite Rock Interaction Experiment, in which unsaturated bentonite columns were introduced into deposition holes in the floor of a 417 m deep tunnel at the Äspö Hard Rock Laboratory in Sweden. Our objectives are to assess the performance of state-of-the-art flow models in reproducing the buffer wetting process and to investigate to which extent dependable predictions of buffer wetting times and saturation patterns can be made based on information collected prior to buffer insertion. This would be important for preventing insertion into unsuitable bedrock environments. Field data and modeling results indicate the development of a de-saturated zone in the rock and show that in most cases, the presence or absence of fractures and flow heterogeneity are more important factors for correct wetting predictions than the total inflow. For instance, for an equal open-hole inflow value, homogeneous inflow yields much more rapid buffer wetting than cases where fractures are represented explicitly thus creating heterogeneous inflow distributions.

  14. A novel ribonuclease with antiproliferative activity from fresh fruiting bodies of the edible mushroom Hypsizigus marmoreus.

    PubMed

    Guan, G P; Wang, H X; Ng, T B

    2007-12-01

    An 18-kDa ribonuclease (RNase) with a novel N-terminal sequence was purified from fresh fruiting bodies of the mushroom Hypsizigus marmoreus. The purification protocol comprised ion exchange chromatography on DEAE cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose and Q-Sepharose and gel filtration by fast protein liquid chromatography on Superdex 75. The starting buffer was 10 mM Tris-HCl buffer (pH 7.2), 10 mM Tris-HCl buffer (pH 7.2), 10 mM NH(4)OAc buffer (pH 5), 10 mM NH(4)HCO(3) buffer (pH 9.4) and 200 mM NH(4)HCO(3) (pH 8.5), respectively. Absorbed proteins were desorbed using NaCl added to the starting buffer. A 42-fold purification of the enzyme was achieved. The RNase was unadsorbed on DEAE cellulose, Affi-gel blue gel and CM-cellulose but adsorbed on Q-Sepharose. It exhibited maximal RNase activity at pH 5 and 70 degrees C. Some RNase activity was detectable at 100 degrees C. It demonstrated the highest ribonucleolytic activity (196 U/mg) toward poly C, the next highest activity (126 U/mg) toward poly A, and much weaker activity toward poly U (48 U/mg) and poly G (41 U/mg). The RNase inhibited [(3)H-methyl]-thymidine uptake by leukemia L1210 cells with an IC(50) of 60 microM.

  15. Interactions of TRIS [tris(hydroxymethyl)aminomethane] and related buffers with peptide backbone: thermodynamic characterization.

    PubMed

    Taha, Mohamed; Lee, Ming-Jer

    2010-10-21

    In a situation which is far from ideal, many buffers have been found to be quite reactive, besides maintaining their stable pH values. On the basis of apparent transfer free energies (ΔG(tr)'), through solubility measurements the interactions of zwitterionic glycine peptides: glycine (Gly), diglycine (Gly(2)), triglycine (Gly(3)), and tetraglycine (Gly(4)), with several common neutral pH, amine-based buffers have been studied. The biological buffers studied in this work, including TRIS, TES, TAPS, TAPSO, and TABS are structurally related and all contain TRIS groups. These buffers have pK(a) values ranging from 7.5-9.0, which allow them to be used in biological, biochemical or environmental studies. We observed negative values of ΔG(tr)' for Gly(3) and Gly(4) from water to buffer, indicating that the interactions are favorable. However, the ΔG(tr)' values are positive for Gly and Gly(2), revealing unfavorable interactions, which except for the latter in TRIS buffer are negative. The surprising result in our data is the unexpected extraordinarily high favorable interactions between TRIS buffer and peptides (in comparison with the effect of the most common denaturants, urea and guanidine hydrochloride). The transfer free energies (ΔG(tr)') of the peptide backbone unit (-CH(2)C=O-NH-) contributions have been estimated from ΔG(tr)' values. We have also investigated the interactions of TRIS buffer with Bovine Serum Albumin (BSA), as a globular protein, using dynamic light scattering (DLS), zeta potential, UV-Visible absorption, fluorescence and Raman spectroscopy measurements. The results indicated that TRIS buffer stabilized the BSA molecules.

  16. Reconnecting tile drainage to riparian buffer hydrology for enhanced nitrate removal.

    PubMed

    Jaynes, D B; Isenhart, T M

    2014-03-01

    Riparian buffers are a proven practice for removing NO from overland flow and shallow groundwater. However, in landscapes with artificial subsurface (tile) drainage, most of the subsurface flow leaving fields is passed through the buffers in drainage pipes, leaving little opportunity for NO removal. We investigated the feasibility of re-routing a fraction of field tile drainage as subsurface flow through a riparian buffer for increasing NO removal. We intercepted an existing field tile outlet draining a 10.1-ha area of a row-cropped field in central Iowa and re-routed a fraction of the discharge as subsurface flow along 335 m of an existing riparian buffer. Tile drainage from the field was infiltrated through a perforated pipe installed 75 cm below the surface by maintaining a constant head in the pipe at a control box installed in-line with the existing field outlet. During 2 yr, >18,000 m (55%) of the total flow from the tile outlet was redirected as infiltration within the riparian buffer. The redirected water seeped through the 60-m-wide buffer, raising the water table approximately 35 cm. The redirected tile flow contained 228 kg of NO. On the basis of the strong decrease in NO concentrations within the shallow groundwater across the buffer, we hypothesize that the NO did not enter the stream but was removed within the buffer by plant uptake, microbial immobilization, or denitrification. Redirecting tile drainage as subsurface flow through a riparian buffer increased its NO removal benefit and is a promising management practice to improve surface water quality within tile-drained landscapes.

  17. Erosion rills offset the efficacy of vegetated buffer strips to mitigate pesticide exposure in surface waters.

    PubMed

    Stehle, Sebastian; Dabrowski, James Michael; Bangert, Uli; Schulz, Ralf

    2016-03-01

    Regulatory risk assessment considers vegetated buffer strips as effective risk mitigation measures for the reduction of runoff-related pesticide exposure of surface waters. However, apart from buffer strip widths, further characteristics such as vegetation density or the presence of erosion rills are generally neglected in the determination of buffer strip mitigation efficacies. This study conducted a field survey of fruit orchards (average slope 3.1-12.2%) of the Lourens River catchment, South Africa, which specifically focused on the characteristics and attributes of buffer strips separating orchard areas from tributary streams. In addition, in-stream and erosion rill water samples were collected during three runoff events and GIS-based modeling was employed to predict losses of pesticides associated with runoff. The results show that erosion rills are common in buffer strips (on average 13 to 24 m wide) of the tributaries (up to 6.5 erosion rills per km flow length) and that erosion rills represent concentrated entry pathways of pesticide runoff into the tributaries during rainfall events. Exposure modeling shows that measured pesticide surface water concentrations correlated significantly (R(2)=0.626; p<0.001) with runoff losses predicted by the modeling approach in which buffer strip width was set to zero at sites with erosion rills; in contrast, no relationship between predicted runoff losses and in-stream pesticide concentrations were detected in the modeling approach that neglected erosion rills and thus assumed efficient buffer strips. Overall, the results of our study show that erosion rills may substantially reduce buffer strip pesticide retention efficacies during runoff events and suggest that the capability of buffer strips as a risk mitigation tool for runoff is largely overestimated in current regulatory risk assessment procedures conducted for pesticide authorization.

  18. Characterization of discontinuous buffer junctions using pH indicators in capillary electrophoresis for protein preconcentration.

    PubMed

    Jurcic, Kristina; Nesbitt, Chandra A; Yeung, Ken K-C

    2006-11-17

    An effective sample preconcentration technique for proteins and peptides was recently developed using capillary electrophoresis (CE) with discontinuous buffers [C.A. Nesbitt, J.T.-M. Lo, K.K.-C. Yeung, J. Chromatogr. A 1073 (2005) 175]. Two buffers of different pH created a junction to trap the sample molecules at their isoelectric points and resulted in over 1000-fold preconcentration for myoglobin within 30 min. To study the formation of pH junctions in CE, a pH indicator, bromothymol blue, is used in this work to reveal the pH changes at the discontinuous buffer boundary. Bromothymol blue (BTB) exhibits a drastic change in its visible absorption spectrum (300-600 nm) going from the acidic to basic pH conditions, and is therefore ideal for visualizing the changes in pH at the junctions created by various buffer combinations. Preconcentration of myoglobin was performed in discontinuous buffers containing BTB. Major differences in the BTB absorption profiles were identified from buffer systems that differ significantly in preconcentration performance, which in turn, allowed for the identification of ideal buffers for sample preconcentration. Up to 2000-fold preconcentrations of myoglobin were achieved in the buffer systems studied in this work. In addition, the role of the electroosmotic flow (EOF) on the preconcentration performance was investigated. A low EOF was found to be desirable, as the pH junction could stay longer in the capillary for accumulation of proteins. The pH junction also displayed characteristics to resist bandbroadening. Potential laminar flow resulted from the mismatched residual EOFs under the two pH conditions within the discontinuous buffers appeared to have minimal effect on the preconcentration. In fact, external applied pressure can be used to control the migration of the pH junction without compromising the protein preconcentration.

  19. Sustained housing-type social buffering following social housing in male rats.

    PubMed

    Kiyokawa, Yasushi; Ishida, Aya; Takeuchi, Yukari; Mori, Yuji

    2016-05-01

    In social animals, recovery from the adverse effects of distressing stimuli is promoted by subsequent cohousing with a conspecific animal(s). This phenomenon has been termed housing-type social buffering. We previously found that social housing induced housing-type social buffering in fear-conditioned male rats. This buffering took the form of attenuated conditioned hyperthermia in response to an auditory conditioned stimulus (CS). Here, we assessed whether this social buffering is sustained even if the subject is housed alone after a period of social housing. When fear-conditioned subjects were housed alone during a 48-h period between conditioning and re-exposure to the auditory CS, they exhibited conditioned hyperthermia in response to the CS. However, conditioned hyperthermia was not observed when the 12-h period of social housing began 24 and 36h after conditioning during the 48-h period. This was not the case when the 12-h period of social housing began 0 and 12h after the conditioning. These results suggest that housing-type social buffering is sustained for 12h after the 12-h period of social housing. We next considered whether increasing the duration of social housing would extend the period of social buffering. We observed social buffering of conditioned hyperthermia 24 and 48, but not 96h after a 24-h period of social housing. These results suggest that social buffering was extended when the duration of social housing was increased. Taken together, our findings indicate that housing-type social buffering is sustained after a period of social housing.

  20. The resurfacing history of Venus: Constraints from buffered crater densities

    NASA Astrophysics Data System (ADS)

    Kreslavsky, Mikhail A.; Ivanov, Mikhail A.; Head, James W.

    2015-04-01

    Because of atmospheric shielding and endogenic resurfacing, the population of impact craters on Venus is small (about a thousand) and consists of large craters. This population has been used in numerous studies with the goal of deciphering the geologic and geodynamic history of Venus, but the nearly spatially random nature of the crater population has complicated efforts to understand this history. Here we utilize the recent 1:15 M-scale global geological map of Venus (Ivanov, M.A., Head, J.W. [2011]. Planet. Space Sci. 59, 1559-1600) to help address this problem. The global geological map provides a stratigraphic sequence of units, and known areas where each unit is exposed on the planet. For each crater on Venus we identify the specific geological units predating and postdating the crater. We perform a statistical analysis of this set of observations with a buffered crater density approach, which rigorously and consistently takes into account the large size of craters and the fact that many craters are known to predate and/or postdate more than one unit. In this analysis we consider crater emplacement as random and resurfacing history as determined (although unknown). We obtain formal confidence intervals for the mean ages of geological units and the mean age differences between the pairs of units at the unit boundaries. We find that (1) size-frequency distributions of craters superposed on each unit are consistent with each other; (2) regional plains and stratigraphically older units have similar crater retention ages; (3) stratigraphically younger units have a mean crater retention age significantly younger than the regional plains. These findings are readily and consistently explained by global resurfacing scenarios and are difficult to reconcile with equilibrium resurfacing scenarios. Our analysis also shows that the latest recorded part of intensive resurfacing period lasted on the order of 10% of the mean surface age (tens of millions of years). The

  1. Photosynthetic activity buffers ocean acidification in seagrass meadows

    NASA Astrophysics Data System (ADS)

    Hendriks, I. E.; Olsen, Y. S.; Ramajo, L.; Basso, L.; Steckbauer, A.; Moore, T. S.; Howard, J.; Duarte, C. M.

    2013-07-01

    Macrophytes growing in shallow coastal zones characterized by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH ranges is in shallow (5-12 m) seagrass (Posidonia oceanica) meadows from 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean and max pHNBS and max ΩAr. Oxygen production positively influenced the range and maximum pHNBS and the range of ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy) influenced ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. ΩAr was positively correlated with the calcium carbonate load of the leaves, demonstrating a direct link between structural parameters, ΩAr and carbonate deposition. There was a direct relationship between ΩAr, influenced directly by meadow LAI, and CaCO3 content of the leaves. Therefore, calcifying organisms, e.g. epiphytes with carbonate skeletons, might benefit from the modification of the carbonate system by the meadow. The meadow might be capable of providing refugia for calcifiers by increasing pH and ΩAr through metabolic activity. There is, however, concern for the ability of seagrasses to provide this refugia function in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, both strongly linked to LAI. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.

  2. Intraspecific variation buffers projected climate change impacts on Pinus contorta

    PubMed Central

    Oney, Brian; Reineking, Björn; O'Neill, Gregory; Kreyling, Juergen

    2013-01-01

    Species distribution modeling (SDM) is an important tool to assess the impact of global environmental change. Many species exhibit ecologically relevant intraspecific variation, and few studies have analyzed its relevance for SDM. Here, we compared three SDM techniques for the highly variable species Pinus contorta. First, applying a conventional SDM approach, we used MaxEnt to model the subject as a single species (species model), based on presence–absence observations. Second, we used MaxEnt to model each of the three most prevalent subspecies independently and combined their projected distributions (subspecies model). Finally, we used a universal growth transfer function (UTF), an approach to incorporate intraspecific variation utilizing provenance trial tree growth data. Different model approaches performed similarly when predicting current distributions. MaxEnt model discrimination was greater (AUC – species model: 0.94, subspecies model: 0.95, UTF: 0.89), but the UTF was better calibrated (slope and bias – species model: 1.31 and −0.58, subspecies model: 1.44 and −0.43, UTF: 1.01 and 0.04, respectively). Contrastingly, for future climatic conditions, projections of lodgepole pine habitat suitability diverged. In particular, when the species' intraspecific variability was acknowledged, the species was projected to better tolerate climatic change as related to suitable habitat without migration (subspecies model: 26% habitat loss or UTF: 24% habitat loss vs. species model: 60% habitat loss), and given unlimited migration may increase amount of suitable habitat (subspecies model: 8% habitat gain or UTF: 12% habitat gain vs. species model: 51% habitat loss) in the climatic period 2070–2100 (SRES A2 scenario, HADCM3). We conclude that models derived from within-species data produce different and better projections, and coincide with ecological theory. Furthermore, we conclude that intraspecific variation may buffer against adverse effects of climate

  3. Biological legacies buffer local species extinction after logging

    PubMed Central

    Rudolphi, Jörgen; Jönsson, Mari T; Gustafsson, Lena

    2014-01-01

    Clearcutting has been identified as a main threat to forest biodiversity. In the last few decades, alternatives to clearcutting have gained much interest. Living and dead trees are often retained after harvest to serve as structural legacies to mitigate negative effects of forestry. However, this practice is widely employed without information from systematic before–after control-impact studies to assess the processes involved in species responses after clearcutting with retention. We performed a large-scale survey of the occurrence of logging-sensitive and red-listed bryophytes and lichens before and after clearcutting with the retention approach. A methodology was adopted that, for the first time in studies on retention approaches, enabled monitoring of location-specific substrates. We used uncut stands as controls to assess the variables affecting the survival of species after a major disturbance. In total, 12 bryophyte species and 27 lichen species were analysed. All were classified as sensitive to logging, and most species are also currently red-listed. We found that living and dead trees retained after final harvest acted as refugia in which logging-sensitive species were able to survive for 3 to 7 years after logging. Depending on type of retention and organism group, between 35% and 92% of the species occurrences persisted on retained structures. Most species observed outside retention trees or patches disappeared. Larger pre-harvest population sizes of bryophytes on dead wood increased the survival probability of the species and hence buffered the negative effects of logging. Synthesis and applications. Careful spatial planning of retention structures is required to fully embrace the habitats of logging-sensitive species. Bryophytes and lichens persisted to a higher degree in retention patches compared to solitary trees or in the clearcut area. Retaining groups of trees in logged areas will help to sustain populations of species over the clearcut phase

  4. The W-W02 Oxygen Fugacity Buffer at High Pressures and Temperatures: Implications for f02 Buffering and Metal-silicate Partitioning

    NASA Technical Reports Server (NTRS)

    Shofner, G. A.; Campbell, A. J.; Danielson, L.; Righter, K.

    2013-01-01

    Oxygen fugacity (fO2) controls multivalent phase equilibria and partitioning of redox-sensitive elements, and it is important to understand this thermodynamic parameter in experimental and natural systems. The coexistence of a metal and its oxide at equilibrium constitutes an oxygen buffer which can be used to control or calculate fO2 in high pressure experiments. Application of 1-bar buffers to high pressure conditions can lead to inaccuracies in fO2 calculations because of unconstrained pressure dependencies. Extending fO2 buffers to pressures and temperatures corresponding to the Earth's deep interior requires precise determinations of the difference in volume (Delta) V) between the buffer phases. Synchrotron x-ray diffraction data were obtained using diamond anvil cells (DAC) and a multi anvil press (MAP) to measure unit cell volumes of W and WO2 at pressures and temperatures up to 70 GPa and 2300 K. These data were fitted to Birch-Murnaghan 3rd-order thermal equations of state using a thermal pressure approach; parameters for W are KT = 306 GPa, KT' = 4.06, and aKT = 0.00417 GPa K-1. Two structural phase transitions were observed for WO2 at 4 and 32 GPa with structures in P21/c, Pnma and C2/c space groups. Equations of state were fitted for these phases over their respective pressure ranges yielding the parameters KT = 190, 213, 300 GPa, KT' = 4.24, 5.17, 4 (fixed), and aKT = 0.00506, 0.00419, 0.00467 GPa K-1 for the P21/c, Pnma and C2/c phases, respectively. The W-WO2 buffer (WWO) was extended to high pressure by inverting the W and WO2 equations of state to obtain phase volumes at discrete pressures (1-bar to 100 GPa, 1 GPa increments) along isotherms (300 to 3000K, 100 K increments). The slope of the absolute fO2 of the WWO buffer is positive with increasing temperature up to approximately 70 GPa and is negative above this pressure. The slope is positive along isotherms from 1000 to 3000K with increasing pressure up to at least 100 GPa. The WWO buffer is at

  5. Comparator circuits with local ramp buffering for a column-parallel single slope ADC

    DOEpatents

    Milkov, Mihail M.

    2016-04-26

    A comparator circuit suitable for use in a column-parallel single-slope analog-to-digital converter comprises a comparator, an input voltage sampling switch, a sampling capacitor arranged to store a voltage which varies with an input voltage when the sampling switch is closed, and a local ramp buffer arranged to buffer a global voltage ramp applied at an input. The comparator circuit is arranged such that its output toggles when the buffered global voltage ramp exceeds the stored voltage. Both DC- and AC-coupled comparator embodiments are disclosed.

  6. The combined effect of glass buffer strips and stitching on the damage tolerance of composites

    NASA Technical Reports Server (NTRS)

    Kullerd, Susan M.

    1993-01-01

    Recent research has demonstrated that through-the-thickness stitching provides major improvements in the damage tolerance of composite laminates loaded in compression. However, the brittle nature of polymer matrix composites makes them susceptible to damage propagation, requiring special material applications and designs to limit damage growth. Glass buffer strips, embedded within laminates, have shown the potential for improving the damage tolerance of unstitched composite laminates loaded in tension. The glass buffer strips, less stiff than the surrounding carbon fibers, arrest crack growth in composites under tensile loads. The present study investigates the damage tolerance characteristics of laminates that contain both stitching and glass buffer strips.

  7. MgO buffer layers on rolled nickel or copper as superconductor substrates

    DOEpatents

    Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

    2001-01-01

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

  8. Method for making MgO buffer layers on rolled nickel or copper as superconductor substrates

    DOEpatents

    Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

    2002-01-01

    Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

  9. Data on four criteria for targeting the placement of conservation buffers in agricultural landscapes

    PubMed Central

    Qiu, Zeyuan; Dosskey, Michael G.; Kang, Yang

    2016-01-01

    Four criteria are generally used to prioritize agricultural lands for placing conservation buffers. The criteria include soil erodibility, hydrological sensitivity, wildlife habitat, and impervious surface rate that capture conservation buffers’ benefits in reducing soil erosion, controlling runoff generation, enhancing wildlife habitat, and mitigating stormwater impacts, respectively. This article describes the data used to derive the values of those attributes and a scheme to classify the values in multi-criteria analysis of conservation buffer placement in “Choosing between alternative placement strategies for conservation buffers using borda count” [1]. PMID:27222843

  10. Influence of phosphate-buffered sucrose solution on early graft function in feline renal autotransplantation.

    PubMed

    Katayama, Masaaki; Okamura, Yasuhiko; Shimamura, Shunsuke; Katayama, Rieko; Kamishina, Hiroaki; Uzuka, Yuji

    2014-10-01

    Graft perfusion with cold heparinized saline has known to induce ischemia and reperfusion injury in feline kidney transplantation. In this study, the effects of phosphate-buffered sucrose solution and heparinized saline solution on early kidney graft function were compared in feline kidney autotransplantation. Perfusion of grafts with or without hypothermic storage with chilled phosphate-buffered sucrose solution prevented ischemia and reperfusion injury despite a very short ischemic time. The results of our study suggest that phosphate-buffered sucrose perfusion and storage solution should be effective to reduce ischemia and reperfusion injury despite a very short ischemic time in feline kidney transplantation.

  11. Resonance transition 795-nm Rubidium laser using 3He buffer gas

    SciTech Connect

    Wu, S S; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K; Beach, R J

    2007-08-02

    We report the first demonstration of a 795-nm Rubidium resonance transition laser using a buffer gas consisting of pure {sup 3}He. This follows our recent demonstration of a hydrocarbon-free 795-nm Rubidium resonance laser which used naturally-occurring He as the buffer gas. Using He gas that is isotopically enriched with {sup 3}He yields enhanced mixing of the Rb fine-structure levels. This enables efficient lasing at reduced He buffer gas pressure, improving thermal management in high average power Rb lasers and enhancing the power scaling potential of such systems.

  12. Approach to the design of monitoring buffer for read-out ASICs

    NASA Astrophysics Data System (ADS)

    Atkin, E. V.; Vinogradov, S. M.

    2017-01-01

    The paper describes the approach to designing built-in monitoring buffers for the purpose of checking the functionality of ASICs as parts of test printed boards. A figure of merit (FOM), based on that analysis is suggested. Features of the FOM, applied to particle physics experiments, are the speed, power consumption, load driving capability and occupied chip area. As an example, illustrating the choice of buffer according to the proposed FOM, there are presented the results of designing a buffer version as part of an ASIC for the CBM MUCH(http://www.fair-center.eu/for-users/experiments/cbm.html).

  13. Buffer layer engineering on graphene via various oxidation methods for atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Takahashi, Nobuaki; Nagashio, Kosuke

    2016-12-01

    The integration of a high-k oxide on graphene using atomic layer deposition requires an electrically reliable buffer layer. In this study, Y was selected as the buffer layer due to its highest oxidation ability among the rare-earth elements, and various oxidation methods (atmospheric, and high-pressure O2 and ozone annealing) were applied to the Y metal buffer layer. By optimizing the oxidation conditions of the top-gate insulator, we successfully improved the capacitance of the top gate Y2O3 insulator and demonstrated a large I on/I off ratio for bilayer graphene under an external electric field.

  14. A Novel Tool to Facilitate the Learning of Buffering Mechanism by Undergraduate Students of the Biological Area

    ERIC Educational Resources Information Center

    Carvalho, Eduardo O.; Nantes, Iseli L.

    2008-01-01

    In this study, the application and evaluation of a novel didactic tool (buffer kit) is described to make it easy for students in the biological area to overcome their conceptual deficiencies that render the learning of the buffering mechanism difficult. The buffer kit was constructed with double-face EVA cards with a conjugated acid formula…

  15. Robustness of spatial patterns in buffered reaction-diffusion systems and its reciprocity with phase plasticity

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Tetsuhiro S.; Kaneko, Kunihiko

    2017-03-01

    The robustness of spatial patterns against perturbations is an indispensable property of developmental processes for organisms, which need to adapt to changing environments. Although specific mechanisms for this robustness have been extensively investigated, little is known about a general mechanism for achieving robustness in reaction-diffusion systems. Here, we propose a buffered reaction-diffusion system, in which active states of chemicals mediated by buffer molecules contribute to reactions, and demonstrate that robustness of the pattern wavelength is achieved by the dynamics of the buffer molecule. This robustness is analytically explained as a result of the scaling properties of the buffered system, which also lead to a reciprocal relationship between the wavelength's robustness and the plasticity of the spatial phase upon external perturbations. Finally, we explore the relevance of this reciprocity to biological systems.

  16. Analytical model for radionuclide transport in the buffer zone of the deep geological disposal

    NASA Astrophysics Data System (ADS)

    Tsao, L. D.; Chen, J. S.; Li, M. H.

    2015-12-01

    Radioactive nuclear waste poses long-term threat to human beings and the environment because that remains radioactive after millions of years. Therefore, radioactive wastes must be isolated from the living environment for millennia. A deep geological disposal entails a combination of four parts: vitrified waste form, imaginary zone, buffer zone and excavation-affected zone. The buffer zone constituted by bentonite clay provides a high level of containment of the radioactivity in the wastes over a very long time period. Analytical solution is an efficient tool for the performance evaluation of the buffer zone. This study develops a new analytical model to diffusion equation in cylindrical coordinate for describing radionuclide transport in the buffer zone. The derived solution is compared against the previous solution to illustrate the validity of previous solution which was derived using a diffusion equation in Cartesian coordinates.

  17. Spatial Characterization of Riparian Buffer Effects on Sediment Loads from Watershed Systems

    EPA Science Inventory

    Understanding all watershed systems and their interactions is a complex, but critical, undertaking when developing practices designed to reduce topsoil loss and chemical/nutrient transport from agricultural fields. The presence of riparian buffer vegetation in agricultural lands...

  18. Characterization of Cu buffer layers for growth of L10-FeNi thin films

    NASA Astrophysics Data System (ADS)

    Mizuguchi, M.; Sekiya, S.; Takanashi, K.

    2010-05-01

    A Cu(001) layer was fabricated on a Au(001) layer to investigate the use of Cu as a buffer layer for growing L10-FeNi thin films. The epitaxial growth of a Cu buffer layer was observed using reflection high-energy electron diffraction. The flatness of the layer improved drastically with an increase in the substrate temperature although the layer was an alloy (AuCu3). An FeNi thin film was epitaxially grown on the AuCu3 buffer layer by alternate monatomic layer deposition and the formation of an L10-FeNi ordered alloy was expected. The AuCu3 buffer layer is thus a promising candidate material for the growth of L10-FeNi thin films.

  19. Critical evaluation of buffering solutions for pKa determination by capillary electrophoresis.

    PubMed

    Fuguet, Elisabet; Reta, Mario; Gibert, Carme; Rosés, Martí; Bosch, Elisabeth; Ràfols, Clara

    2008-07-01

    The performance of the most common and also some other less common CE buffers has been tested for the pKa determination of several types of compounds (pyridine, amines, and phenols). The selected buffers cover a pH ranging from 3.7 to 11.8. Whereas some buffers, like acetic acid/acetate, BisTrisH+/BisTris, TrisH+/Tris, CHES/CHES-, and CAPS/CAPS- can be used with all type of analytes, others like ammonium/ammonia, butylammonium/butylammonia, ethylammonium/ethylammonia, diethylammonium/diethylammonia, and hydrogenphosphate/phosphate are not recommended because they interact with a wide range of compounds. The rest of the tested buffers (dihydrogenphosphate/hydrogenphosphate, MES/MES-, HEPES/HEPES-, and boric acid/borate) can show specific interactions depending on the nature of the analytes, and their use in some applications should be restricted.

  20. Tested Demonstrations: Visualization of Buffer Action and the Acidifying Effect of Carbon Dioxide.

    ERIC Educational Resources Information Center

    Gilbert, George L., Ed.

    1985-01-01

    Presents a buffer demonstration which features visualization of the effects of carbon dioxide on pH. Background information, list of materials needed, procedures used, and a discussion of results obtained are included. (JN)

  1. Social Support for Divorced Fathers' Parenting: Testing a Stress-Buffering Model*

    PubMed Central

    DeGarmo, David S.; Patras, Joshua; Eap, Sopagna

    2008-01-01

    A stress-buffering hypothesis for parenting was tested in a county-representative sample of 218 divorced fathers. Social support for parenting (emergency and nonemergency child care, practical support, financial support) was hypothesized to moderate effects of stress (role overload, coparental conflict, and daily hassles) on fathers’ quality parenting. No custody fathers relied more on relatives compared with custodial fathers, who relied more on new partners for parenting support. No differences by custody status were found on levels of support or parenting over time. Parenting support buffered effects of change in role overload and coparenting conflict on coercive parenting and buffered effects of change in daily hassles on prosocial parenting. Buffer effects were more predictive over time. Implications for practice and preventive intervention strategies are discussed. PMID:19177181

  2. Describing the Access Network by means of Router Buffer Modelling: A New Methodology

    PubMed Central

    Fernández-Navajas, Julián; Gállego, José Ramón; Canales, María

    2014-01-01

    The behaviour of the routers' buffer may affect the quality of service (QoS) of network services under certain conditions, since it may modify some traffic characteristics, as delay or jitter, and may also drop packets. As a consequence, the characterization of the buffer is interesting, especially when multimedia flows are transmitted and even more if they transport information with real-time requirements. This work presents a new methodology with the aim of determining the technical and functional characteristics of real buffers (i.e., behaviour, size, limits, and input and output rate) of a network path. It permits the characterization of intermediate buffers of different devices in a network path across the Internet. PMID:25152904

  3. Human skin buffering capacity against a reference base sodium hydroxide: in vitro model.

    PubMed

    Ayer, Jean; Maibach, Howard I

    2008-01-01

    This study assesses the possibility of using an in vitro model as an introduction to clinical human models for evaluating the buffering capacity of skin when an irritant is topically applied. Sodium hydroxide (NaOH) was utilized as a model base with a view to elucidate information on preventing and/or treating base-induced damage and better understand buffering mechanisms. NaOH was evaluated in 3 concentrations (0.1N, 0.05N, and 0.025N) to determine if the skin's ability to buffer these solutions was dependent on the concentration of the topically applied solution. De-ionized water (negative control) and unexposed skin (blank control) were also utilized. The model permitted quantitative estimates of buffering capacity and its rapid diminution.

  4. Identifying network motifs that buffer front-to-back signaling in polarized neutrophils.

    PubMed

    Wang, Yanqin; Ku, Chin-Jen; Zhang, Elizabeth R; Artyukhin, Alexander B; Weiner, Orion D; Wu, Lani F; Altschuler, Steven J

    2013-05-30

    Neutrophil polarity relies on local, mutual inhibition to segregate incompatible signaling circuits to the leading and trailing edges. Mutual inhibition alone should lead to cells having strong fronts and weak backs or vice versa. However, analysis of cell-to-cell variation in human neutrophils revealed that back polarity remains consistent despite changes in front strength. How is this buffering achieved? Pharmacological perturbations and mathematical modeling revealed a functional role for microtubules in buffering back polarity by mediating positive, long-range crosstalk from front to back; loss of microtubules inhibits buffering and results in anticorrelation between front and back signaling. Furthermore, a systematic, computational search of network topologies found that a long-range, positive front-to-back link is necessary for back buffering. Our studies suggest a design principle that can be employed by polarity networks: short-range mutual inhibition establishes distinct signaling regions, after which directed long-range activation insulates one region from variations in the other.

  5. Directions for Determining Buffer Zone Distances for Commodity and Structural Fumigation with Methyl Bromide

    EPA Pesticide Factsheets

    Buffer zones for commodity and food handling structural applications are distributed across numerous tables. This document provides directions for determining the factors to use to identify the correct table for a given application.

  6. Effect of surface and subsurface heterogeneity on the hydrological response of a grassed buffer zone

    NASA Astrophysics Data System (ADS)

    Gatel, Laura; Lauvernet, Claire; Carluer, Nadia; Paniconi, Claudio

    2016-11-01

    Grassed buffer zones are an effective method to reduce contaminant impacts on aquatic environments. The general objective of this study is to explore the impact of both surface and subsurface heterogeneity on the hydrological responses of a vegetative buffer strip. Heterogeneity is described by two variables, microtopography and saturated hydraulic conductivity. Numerous surface and subsurface heterogeneity scenarios were simulated with a physically-based numerical model of coupled surface/subsurface processes. The scenarios were evaluated relative to data from an experimental vegetative filter in a Beaujolais vineyard, France. The subsurface scenarios show that conductivity heterogeneity plays a key role on the buffer strip's capacity to infiltrate incoming surface runoff and on the ensuing runoff pathways. The conjunctive surface and subsurface scenarios indicate that microtopography variability is comparatively less influential on the hydrological interactions and pathways within the buffer strip, and that representing this heterogeneity via appropriate statistical distributions can be a good assumption in practice.

  7. INFLUENCE OF BORATE BUFFERS ON THE ELECTROPHORETIC BEHAVIOR OF HUMIC SUBSTANCES IN CAPILLARY ZONE ELECTROPHORESIS

    EPA Science Inventory

    The influence of tetrahydroxyborate ions on the electrophoretic mobility of humic acids was evaluated by capillary electrophoresis (CE). Depending on the molarity of borate ions in the separation buffer, the humic acids exhibit electropherograms with sharp peaks consistently exte...

  8. Performance of a 10 Gbps FSO System Implementing Novel Beam Tracking a Dynamic Buffering Modem

    NASA Technical Reports Server (NTRS)

    Kiriazes, John; Valencia, J. Emilio; Peach, Robert; Visone, Chris; Burdge, Geoffrey; Vickers, John; Leclerc, Troy; Sauer, Paul; Andrews, Larry; Phillips, Ron

    2012-01-01

    A 10 Gbps Free space optical (FSO) system implements beam tracking, a high dynamic range optical receiver, and a dynamic buffering packet modem. Performance was characterized at the 4.5 km Shuttle Landing Facility at Kennedy Space Center Florida.

  9. Critical CuI buffer layer surface density for organic molecular crystal orientation change

    SciTech Connect

    Ahn, Kwangseok; Kim, Jong Beom; Lee, Dong Ryeol; Kim, Hyo Jung; Lee, Hyun Hwi

    2015-01-21

    We have determined the critical surface density of the CuI buffer layer inserted to change the preferred orientation of copper phthalocyanine (CuPc) crystals grown on the buffer layer. X-ray reflectivity measurements were performed to obtain the density profiles of the buffer layers and out-of-plane and 2D grazing-incidence X-ray diffraction measurements were performed to determine the preferred orientations of the molecular crystals. Remarkably, it was found that the preferred orientation of the CuPc film is completely changed from edge-on (1 0 0) to face-on (1 1 −2) by a CuI buffer layer with a very low surface density, so low that a large proportion of the substrate surface is bare.

  10. Describing the access network by means of router buffer modelling: a new methodology.

    PubMed

    Sequeira, Luis; Fernández-Navajas, Julián; Saldana, Jose; Gállego, José Ramón; Canales, María

    2014-01-01

    The behaviour of the routers' buffer may affect the quality of service (QoS) of network services under certain conditions, since it may modify some traffic characteristics, as delay or jitter, and may also drop packets. As a consequence, the characterization of the buffer is interesting, especially when multimedia flows are transmitted and even more if they transport information with real-time requirements. This work presents a new methodology with the aim of determining the technical and functional characteristics of real buffers (i.e., behaviour, size, limits, and input and output rate) of a network path. It permits the characterization of intermediate buffers of different devices in a network path across the Internet.

  11. Continuous-flow electrophoresis: Membrane-associated deviations of buffer pH and conductivity

    NASA Technical Reports Server (NTRS)

    Smolka, A. J. K.; Mcguire, J. K.

    1978-01-01

    The deviations in buffer pH and conductivity which occur near the electrode membranes in continuous-flow electrophoresis were studied in the Beckman charged particle electrophoresis system and the Hanning FF-5 preparative electrophoresis instrument. The nature of the membranes separating the electrode compartments from the electrophoresis chamber, the electric field strength, and the flow rate of electrophoresis buffer were all found to influence the formation of the pH and conductivity gradients. Variations in electrode buffer flow rate and the time of electrophoresis were less important. The results obtained supported the hypothesis that a combination of Donnan membrane effects and the differing ionic mobilities in the electrophoresis buffer was responsible for the formation of the gradients. The significance of the results for the design and stable operation of continuous-flow electrophoresis apparatus was discussed.

  12. Vegetative environmental buffers for reducing downwind odor and VOCs from tunnel-ventilated swine barn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scientists have investigated methods for reducing odor emissions from livestock buildings for decades, yet few technologies have proven effective. Vegetative Environmental Buffers (VEBs), which are specially designed combinations of trees, shrubs and grasses, have shown promise in recent years for ...

  13. Gilliam County Riparian Buffers; 2002-2003 Annual Report.

    SciTech Connect

    Coiner, Josh

    2003-05-01

    excessive. In counties such as Gilliam, most tracts of land are large parcels. If multiple project areas occur in the same tract then you have one contract per tract. This reduces your total number in a lot of cases. In year 1 there were 6 contracts negotiated and approved in the CREP program. Prior to the contract there were a total of 9. The program started in 1998. The numbers will only increase in year 2. Year two should be a drastic improvement over year one. There has already been several projects proposed that may or may not be approved during year 2. There are 367.4 acres of land that has been proposed in either CREP or CCRP, which would include 30.94 miles of stream buffered on both sides.

  14. Breeding Bird Community Continues to Colonize Riparian Buffers Ten Years after Harvest

    PubMed Central

    2015-01-01

    Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1–2 years) and long-term (~10 years) avian community responses (occupancy and abundance) to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact experimental approach and temporally replicated point counts analyzed within a Bayesian framework. Our experimental design consisted of forested control sites with no harvest, sites with relatively narrow (~13m) forested buffers on each side of the stream, and sites with wider (~30m) and more variable width unharvested buffer. Buffer treatments exhibited a 31–44% increase in mean species richness in the post-harvest years, a pattern most evident 10 years post-harvest. Post-harvest, species turnover was much higher on both treatments (63–74%) relative to the controls (29%). We did not find evidence of local extinction for any species but found strong evidence (no overlap in 95% credible intervals) for an increase in site occupancy on both Narrow (short-term: 7%; long-term 29%) and Wide buffers (short-term: 21%; long-term 93%) relative to controls after harvest. We did not find a treatment effect on total avian abundance. When assessing relationships between buffer width and site level abundance of four riparian specialists, we did not find strong evidence of reduced abundance in Narrow or Wide buffers. Silviculture regulations in this region dictate average buffer widths on small and large permanent streams that range

  15. Breeding Bird Community Continues to Colonize Riparian Buffers Ten Years after Harvest.

    PubMed

    Pearson, Scott F; Giovanini, Jack; Jones, Jay E; Kroll, Andrew J

    2015-01-01

    Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1-2 years) and long-term (~10 years) avian community responses (occupancy and abundance) to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact experimental approach and temporally replicated point counts analyzed within a Bayesian framework. Our experimental design consisted of forested control sites with no harvest, sites with relatively narrow (~13 m) forested buffers on each side of the stream, and sites with wider (~30 m) and more variable width unharvested buffer. Buffer treatments exhibited a 31-44% increase in mean species richness in the post-harvest years, a pattern most evident 10 years post-harvest. Post-harvest, species turnover was much higher on both treatments (63-74%) relative to the controls (29%). We did not find evidence of local extinction for any species but found strong evidence (no overlap in 95% credible intervals) for an increase in site occupancy on both Narrow (short-term: 7%; long-term 29%) and Wide buffers (short-term: 21%; long-term 93%) relative to controls after harvest. We did not find a treatment effect on total avian abundance. When assessing relationships between buffer width and site level abundance of four riparian specialists, we did not find strong evidence of reduced abundance in Narrow or Wide buffers. Silviculture regulations in this region dictate average buffer widths on small and large permanent streams that range from

  16. How the 'slow' Ca(2+) buffer parvalbumin affects transmitter release in nanodomain-coupling regimes.

    PubMed

    Eggermann, Emmanuel; Jonas, Peter

    2011-12-04

    Parvalbumin is thought to act in a manner similar to EGTA, but how a slow Ca(2+) buffer affects nanodomain-coupling regimes at GABAergic synapses is unclear. Direct measurements of parvalbumin concentration and paired recordings in rodent hippocampus and cerebellum revealed that parvalbumin affects synaptic dynamics only when expressed at high levels. Modeling suggests that, in high concentrations, parvalbumin may exert BAPTA-like effects, modulating nanodomain coupling via competition with local saturation of endogenous fixed buffers.

  17. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration

    USGS Publications Warehouse

    Haukos, David A.; Johnson, Lacrecia A.; Smith, Loren M.; McMurry, Scott T.

    2016-01-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30–60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands.

  18. Pulsed Laser Deposition of YBCO With Yttrium Oxide Buffer Layers (Postprint)

    DTIC Science & Technology

    2012-02-01

    AFRL-RZ-WP-TP-2012-0092 PULSED LASER DEPOSITION OF YBCO WITH YTTRIUM OXIDE BUFFER LAYERS (POSTPRINT) Paul N. Barnes, Timothy J. Haugan...Paper Postprint 01 January 2002 – 01 January 2004 4. TITLE AND SUBTITLE PULSED LASER DEPOSITION OF YBCO WITH YTTRIUM OXIDE BUFFER LAYERS (POSTPRINT...Textured metallic substrate based HTS coated conductors with the YBCO /CeO2/YSZ/CeO2/Ni architecture have already been shown to exhibit high current

  19. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration.

    PubMed

    Haukos, David A; Johnson, Lacrecia A; Smith, Loren M; McMurry, Scott T

    2016-10-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30-60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands.

  20. Managing biosolids runoff phosphorus using buffer strips enhanced with drinking water treatment residuals.

    PubMed

    Wagner, D J; Elliott, H A; Brandt, R C; Jaiswal, D

    2008-01-01

    Vegetated buffers strips typically have limited ability to reduce delivery of dissolved phosphorus (DP) from agricultural fields to surface waters. A field study was conducted to evaluate the ability of buffer strips enhanced with drinking water treatment residuals (WTRs) to control runoff P losses from surface-applied biosolids characterized by high water-extractable P (4 g kg(-)(1)). Simulated rainfall (62.4 mm h(-1)) was applied to grassed plots (3 m x 10.7 m including a 2.67 m downslope buffer) surface-amended with biosolids at 102 kg P ha(-1) until 30 min of runoff was collected. With buffer strips top-dressed with WTR (20 Mg ha(-1)), runoff total P (TP = 2.5 mg L(-1)) and total DP (TDP = 1.9 mg L(-1)) were not statistically lower (alpha = 0.05) compared to plots with unamended grass buffers (TP = 2.7 mg L(-1); TDP = 2.6 mg L(-1)). Although the applied WTR had excess capacity (Langmuir P maxima of 25 g P kg(-1)) to sorb all runoff P, kinetic experiments suggest that sheet flow travel time across the buffers ( approximately 30 s) was insufficient for significant P reduction. Effective interception of dissolved P in runoff water by WTR-enhanced buffer strips requires rapid P sorption kinetics and hydrologic flow behavior ensuring sufficient runoff residence time and WTR contact in the buffer. Substantial phosphate-adsorbent contact opportunity may be more easily achieved by incorporating WTRs into P-enriched soils or blending WTRs with applied P sources.