Adaptability and stability of soybean genotypes in off-season cultivation.

PubMed

Batista, R O; Hamawaki, R L; Sousa, L B; Nogueira, A P O; Hamawaki, O T

2015-08-14

The oil and protein contents of soybean grains are important quantitative traits for use in breeding. However, few breeding programs perform selection based on these traits in different environments. This study assessed the adaptability and stability of 14 elite early soybean breeding lines in off-season cultivation with respect to yield, and oil and protein contents. A range of statistical methods was applied and these analyses indicated that for off-season cultivation, the lines UFUS 5 and UFUS 10 could be recommended due to their superior performance in grain yield, oil content, and specific adaptability to unfavorable environments along with high stability in these characteristics. Also recommended were UFUS 06, which demonstrated superior performance in all three tested characteristics and showed adaptation to favorable environments, and UFUS 13, which showed high adaptability and stability and a superior performance for protein content.

Stability of surface nanobubbles

NASA Astrophysics Data System (ADS)

Maheshwari, Shantanu; van der Hoef, Martin; Zhang, Xuehua; Lohse, Detlef

2015-11-01

We have studied the stability and dissolution of surface nanobubbles on the chemical heterogenous surface by performing Molecular Dynamics (MD) simulations of binary mixture consists of Lennard-Jones (LJ) particles. Recently our group has derived the exact expression for equilibrium contact angle of surface nanobubbles as a function of oversaturation of the gas concentration in bulk liquid and the lateral length of bubble. It has been showed that the contact line pinning and the oversaturation of gas concentration in bulk liquid is crucial in the stability of surface nanobubbles. Our simulations showed that how pinning of the three-phase contact line on the chemical heterogenous surface lead to the stability of the nanobubble. We have calculated the equilibrium contact angle by varying the gas concentration in bulk liquid and the lateral length of the bubble. Our results showed that the equilibrium contact angle follows the expression derived analytically by our group. We have also studied the bubble dissolution dynamics and showed the ''stick-jump'' mechanism which was also observed experimentally in case of dissolution of nanodrops.

Habitable Exoplanet Imager Optical-Mechanical Design and Analysis

NASA Technical Reports Server (NTRS)

Gaskins, Jonathan; Stahl, H. Philip

2017-01-01

The Habitable Exoplanet Imager (HabEx) is a space telescope currently in development whose mission includes finding and spectroscopically characterizing exoplanets. Effective high-contrast imaging requires tight stability requirements of the mirrors to prevent issues such as line of sight and wavefront errors. PATRAN and NASTRAN were used to model updates in the design of the HabEx telescope and find how those updates affected stability. Most of the structural modifications increased first mode frequencies and improved line of sight errors. These studies will be used to help define the baseline HabEx telescope design.

Ultrastructural and some functional changes in tumor cells treated with stabilized iron oxide nanoparticles.

PubMed

Yurchenko, O V; Todor, I N; Khayetsky, I K; Tregubova, N A; Lukianova, N Yu; Chekhun, V F

2010-12-01

To study the ultrastructure and some functional indexes of tumor cells treated with stabilized iron nanoparticles in vitro. 3-[4,5dimethylthiazol-2-1]-2,5-diphenyltetrazolium bromide (MTT)-test, electron microscopy, polarography with applying of closed Clark's electrode. It was shown that cultivation of cells with stabilized Fe(3)O(4) leads to intracellular accumulation of ferromagnetic nanoparticles. The most active ferromagnetic uptake by cells has been observed after 24 and 48 h of incubation. The presence of ferromagnetic in cells led to altered mitochondrial structure that caused the decrease of oxygen uptake rate in the cells of all studied lines. Ferromagnetic released from the majority of cells via exocytosis or clasmacytosis after a certain period of time. The number of dead cells or cells with severe damage was moderate, so cytotoxic action of stabilized iron oxide nanoparticles was minimal toward the studied cell lines. the presence of ferromagnetic nanoparticles in culture medium led to alterations in mitochondria ultrastructural organization and decrease of oxygen uptake by mitochondria in sensitive and anticancer-drugs resistant cells.

Design of rapid prototype of UAV line-of-sight stabilized control system

NASA Astrophysics Data System (ADS)

Huang, Gang; Zhao, Liting; Li, Yinlong; Yu, Fei; Lin, Zhe

2018-01-01

The line-of-sight (LOS) stable platform is the most important technology of UAV (unmanned aerial vehicle), which can reduce the effect to imaging quality from vibration and maneuvering of the aircraft. According to the requirement of LOS stability system (inertial and optical-mechanical combined method) and UAV's structure, a rapid prototype is designed using based on industrial computer using Peripheral Component Interconnect (PCI) and Windows RTX to exchange information. The paper shows the control structure, and circuit system including the inertial stability control circuit with gyro and voice coil motor driven circuit, the optical-mechanical stability control circuit with fast-steering-mirror (FSM) driven circuit and image-deviation-obtained system, outer frame rotary follower, and information-exchange system on PC. Test results show the stability accuracy reaches 5μrad, and prove the effectiveness of the combined line-of-sight stabilization control system, and the real-time rapid prototype runs stable.

Constructing Hopf bifurcation lines for the stability of nonlinear systems with two time delays

NASA Astrophysics Data System (ADS)

Nguimdo, Romain Modeste

2018-03-01

Although the plethora real-life systems modeled by nonlinear systems with two independent time delays, the algebraic expressions for determining the stability of their fixed points remain the Achilles' heel. Typically, the approach for studying the stability of delay systems consists in finding the bifurcation lines separating the stable and unstable parameter regions. This work deals with the parametric construction of algebraic expressions and their use for the determination of the stability boundaries of fixed points in nonlinear systems with two independent time delays. In particular, we concentrate on the cases for which the stability of the fixed points can be ascertained from a characteristic equation corresponding to that of scalar two-delay differential equations, one-component dual-delay feedback, or nonscalar differential equations with two delays for which the characteristic equation for the stability analysis can be reduced to that of a scalar case. Then, we apply our obtained algebraic expressions to identify either the parameter regions of stable microwaves generated by dual-delay optoelectronic oscillators or the regions of amplitude death in identical coupled oscillators.

Employing static excitation control and tie line reactance to stabilize wind turbine generators

NASA Technical Reports Server (NTRS)

Hwang, H. H.; Mozeico, H. V.; Guo, T.

1978-01-01

An analytical representation of a wind turbine generator is presented which employs blade pitch angle feedback control. A mathematical model was formulated. With the functioning MOD-0 wind turbine serving as a practical case study, results of computer simulations of the model as applied to the problem of dynamic stability at rated load are also presented. The effect of the tower shadow was included in the input to the system. Different configurations of the drive train, and optimal values of the tie line reactance were used in the simulations. Computer results revealed that a static excitation control system coupled with optimal values of the tie line reactance would effectively reduce oscillations of the power output, without the use of a slip clutch.

The Study on Development of Light-Weight Foamed Mortar for Tunnel Backfill

NASA Astrophysics Data System (ADS)

Ma, Sang-Joon; Kang, Eun-Gu; Kim, Dong-Min

This study was intended to develop the Light-Weight Foamed Mortar which is used for NATM Composite lining backfill. In the wake of the study, the mixing method which satisfies the requirements for compressive strength, permeability coefficient, fluidity, specific gravity and settlement was developed and moreover field applicability was verified through the model test. Thus the mixing of Light-Weight Foamed Mortar developed in this study is expected to be applicable to NATM Composite lining, thereby making commitment to improving the stability and drainage performance of lining.

Towards attosecond synchronization of remote mode-locked lasers using stabilized transmission of optical comb frequencies

NASA Astrophysics Data System (ADS)

Wilcox, R. B.; Byrd, J. M.; Doolittle, L. R.; Holzwarth, R.; Huang, G.

2011-09-01

We propose a method of synchronizing mode-locked lasers separated by hundreds of meters with the possibility of achieving sub-fs performance by locking the phases of corresponding lines in the optical comb spectrum. The optical phase from one comb line is transmitted to the remote laser over an interferometrically stabilized link by locking a single frequency laser to a comb line with high phase stability. We describe how these elements are integrated into a complete system and estimate the potential performance.

Comparative study of a novel application of automated HR HPV assay and stability in a previously untested Preservative media.

PubMed

Morel, Mike E; McBride, Simon E; Gomez, Maria P

2017-12-01

The suitability and stability of cervical cells in Novaprep media (NHQ) for certain HPV assays is unknown. We evaluated the accuracy of an automated HPV assay (Abbott RealTime HR HPV) for cervical cells prepared in NHQ and NHQ with a pre-treatment to mimic a worst case clinical use, compared to the assay manufacturers media; repeatability and reproducibility of HPV results and the stability of detectable HPV in NHQ over time compared to CE marked liquid based cytology preservatives. Cell lines were used to simulate patient samples. Cells stored in NHQ produced accurate, repeatable and reproducible results. Stability in NHQ was comparable to the best performing LBC, with at least 7 months' stability at 18-25°C, 2-8°C, -20°C and -80°C; and at least 3 months' stability at 40°C. Similar results were obtained for pre-treated NHQ except only 3.5 months' stability at 18-25°C. Cell line samples in all media and concentrations tested were detected appropriately by the assay. Based on this first stage validation analytical study, cervical cells stored in NHQ are suitable for the Realtime HPV assay. There should be no reservations for inclusion of NHQ in any further validation and clinical performance evaluation of this assay. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

The effects of estradiol and selective estrogen receptor modulators on gene expression and messenger RNA stability in immortalized sheep endometrial stromal cells and human endometrial adenocarcinoma cells.

PubMed

Farnell, Yuhua Z; Ing, Nancy H

2003-03-01

The purpose of this study was to identify an endometrial cell line that maintained the E2 up-regulation of estrogen receptor (ER) mRNA by enhanced message stability and to assess its dependence on ER protein. Estradiol (E2) effects on gene expression were measured in three cell lines: one immortalized from sheep endometrial stroma (ST) and two from human endometrial adenocarcinomas (Ishikawa and ECC-1). E2 up-regulated ER mRNA levels in ST and Ishikawa cells, but down-regulated ER mRNA levels in ECC-1 cells. E2 up-regulated progesterone receptor (PR), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and transforming growth factor-alpha (TGF-alpha) in both Ishikawa and ECC-1 cells. The selective estrogen receptor modulator ICI 182,780 antagonized the E2-induced up-regulation of ER and/or PR mRNA levels in all three cells, while another, GW 5638, antagonized the up-regulation of PR mRNA in Ishikawa and ECC-1 cells. In mechanistic studies, E2 had no effect on ER mRNA stability in ST cells and it destabilized ER mRNA in ECC-1 cells. Thus, Ishikawa cells appear to be the most physiologically relevant cell line in which to study the up-regulation of ER mRNA levels by enhanced mRNA stability. Its antagonism by ICI 182,780 reveals that ER protein is involved in this E2 response.

A strategy to accelerate protein production from a pool of clones in Chinese hamster ovary cells for toxicology studies.

PubMed

Hu, Zhilan; Hsu, Wendy; Pynn, Abby; Ng, Domingos; Quicho, Donna; Adem, Yilma; Kwong, Zephie; Mauger, Brad; Joly, John; Snedecor, Bradley; Laird, Michael W; Andersen, Dana C; Shen, Amy

2017-11-01

In the biopharmaceutical industry, a clonally derived cell line is typically used to generate material for investigational new drug (IND)-enabling toxicology studies. The same cell line is then used to generate material for clinical studies. If a pool of clones can be used to produce material for IND-enabling toxicology studies (Pool for Tox (PFT) strategy) during the time a lead clone is being selected for clinical material production, the toxicology studies can be accelerated significantly (approximately 4 months at Genentech), leading to a potential acceleration of 4 months for the IND submission. We explored the feasibility of the PFT strategy with three antibodies-mAb1, mAb2, and mAb3-at the 2 L scale. For each antibody, two lead cell lines were identified that generated material with similar product quality to the material generated from the associated pool. For two antibody molecules, mAb1 and mAb2, the material generated by the lead cell lines from 2 L bioreactors was tested in an accelerated stability study and was shown to have stability comparable to the material generated by the associated pool. Additionally, we used this approach for two antibody molecules, mAb4 and mAb5, at Tox and GMP production. The materials from the Tox batch at 400 L scale and three GMP batches at 2000 L scale have comparable product quality attributes for both molecules. Our results demonstrate the feasibility of using a pool of clonally derived cell lines to generate material of similar product quality and stability for use in IND-enabling toxicology studies as was derived from the final production clone, which enabled significant acceleration of timelines into clinical development. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1449-1455, 2017. © 2017 American Institute of Chemical Engineers.

Fiber-optic delay-line stabilization of heterodyne optical signal generator and method using same

NASA Technical Reports Server (NTRS)

Logan, Ronald T. (Inventor)

1997-01-01

The present invention is a laser heterodyne frequency generator system with a stabilizer for use in the microwave and millimeter-wave frequency ranges utilizing a photonic mixer as a photonic phase detector in a stable optical fiber delay-line. Phase and frequency fluctuations of the heterodyne laser signal generators are stabilized at microwave and millimeter wave frequencies by a delay line system operating as a frequency discriminator. The present invention is free from amplifier and mixer 1/.function. noise at microwave and millimeter-wave frequencies that typically limit phase noise performance in electronic cavity stabilized electronic oscillators. Thus, 1/.function. noise due to conventional mixers is eliminated and stable optical heterodyne generation of electrical signals is achieved.

An MHD variational principle that admits reconnection

NASA Technical Reports Server (NTRS)

Rilee, M. L.; Sudan, R. N.; Pfirsch, D.

1997-01-01

The variational approach of Pfirsch and Sudan's averaged magnetohydrodynamics (MHD) to the stability of a line-tied current layer is summarized. The effect of line-tying on current sheets that might arise in line-tied magnetic flux tubes by estimating the growth rates of a resistive instability using a variational method. The results show that this method provides a potentially new technique to gauge the stability of nearly ideal magnetohydrodynamic systems. The primary implication for the stability of solar coronal structures is that tearing modes are probably constant at work removing magnetic shear from the solar corona.

On the stability of an infinite swept attachment line boundary layer

NASA Technical Reports Server (NTRS)

Hall, P.; Mallik, M. R.; Poll, D. I. A.

1984-01-01

The instability of an infinite swept attachment line boundary layer is considered in the linear regime. The basic three dimensional flow is shown to be susceptible to travelling wave disturbances which propagate along the attachment line. The effect of suction on the instability is discussed and the results suggest that the attachment line boundary layer on a swept wing can be significantly stabilized by extremely small amounts of suction. The results obtained are in excellent agreement with the available experimental observations.

The taccalonolides: microtubule stabilizers that circumvent clinically relevant taxane resistance mechanisms.

PubMed

Risinger, April L; Jackson, Evelyn M; Polin, Lisa A; Helms, Gregory L; LeBoeuf, Desiree A; Joe, Patrick A; Hopper-Borge, Elizabeth; Ludueña, Richard F; Kruh, Gary D; Mooberry, Susan L

2008-11-01

The taccalonolides are a class of structurally and mechanistically distinct microtubule-stabilizing agents isolated from Tacca chantrieri. A crucial feature of the taxane family of microtubule stabilizers is their susceptibility to cellular resistance mechanisms including overexpression of P-glycoprotein (Pgp), multidrug resistance protein 7 (MRP7), and the betaIII isotype of tubulin. The ability of four taccalonolides, A, E, B, and N, to circumvent these multidrug resistance mechanisms was studied. Taccalonolides A, E, B, and N were effective in vitro against cell lines that overexpress Pgp and MRP7. In addition, taccalonolides A and E were highly active in vivo against a doxorubicin- and paclitaxel-resistant Pgp-expressing tumor, Mam17/ADR. An isogenic HeLa-derived cell line that expresses the betaIII isotype of tubulin was generated to evaluate the effect of betaIII-tubulin on drug sensitivity. When compared with parental HeLa cells, the betaIII-tubulin-overexpressing cell line was less sensitive to paclitaxel, docetaxel, epothilone B, and vinblastine. In striking contrast, the betaIII-tubulin-overexpressing cell line showed greater sensitivity to all four taccalonolides. These data cumulatively suggest that the taccalonolides have advantages over the taxanes in their ability to circumvent multiple drug resistance mechanisms. The ability of the taccalonolides to overcome clinically relevant mechanisms of drug resistance in vitro and in vivo confirms that the taccalonolides represent a valuable addition to the family of microtubule-stabilizing compounds with clinical potential.

Use of near-isogenic wheat lines to determine the glutenin composition and functionality requirements for flour tortillas.

PubMed

Mondal, Suchismita; Tilley, Michael; Alviola, Juma Novi; Waniska, Ralph D; Bean, Scott R; Glover, Karl D; Hays, Dirk B

2008-01-09

In wheat ( Triticum aestivum L), the synthesis of high molecular weight (HMW) glutenins (GS) is controlled by three heterologous genetic loci present on the long arms of group 1 wheat chromosomes. The loci Glu-A1, Glu-B1, and Glu-D1 and their allelic variants play important roles in the functional properties of wheat flour. This study focused on understanding the functionality of these protein subunits on tortilla quality. Near-isogenic wheat lines in which one or more of these loci were absent or deleted were used. Tortillas were prepared from each deletion line and the parent lines. The elimination of certain HMW-GS alleles alter distinct but critical aspects of tortilla quality such as diameter, shelf stability, and overall quality. Two deletion lines possessing HMW-GS 17 + 18 at Glu-B1 and deletions in Glu-A1 and Glu-D1 had significantly larger tortilla diameters, yet tortilla shelf life was compromised or unchanged from the parent lines used to develop the deletion lines or the commercial tortilla flour used as a control. Alternatively, a deletion line possessing Glu-A1 and Glu-D1 (HMW-GS 1, 5 + 10) and a deletion in Glu-B1 also significantly improved tortilla diameters. Whereas the increase in diameter was less than the line possessing only HMW-GS 17 + 18 at Glu-B1, the stability of the tortillas were, however, maintained and improved as compared to the parent lines containing a full compliment of HMW-GS. Thus, the presence of subunits 5 + 10 at Glu-D1 alone or in combination with subunit 1 at Glu-A1 appears to provide a compromise of improvement in dough extensibility for improved tortilla diameters while also providing sufficient gluten strength to maintain ideal shelf stability.

Trapped particle stability for the kinetic stabilizer

NASA Astrophysics Data System (ADS)

Berk, H. L.; Pratt, J.

2011-08-01

A kinetically stabilized axially symmetric tandem mirror (KSTM) uses the momentum flux of low-energy, unconfined particles that sample only the outer end-regions of the mirror plugs, where large favourable field-line curvature exists. The window of operation is determined for achieving magnetohydrodynamic (MHD) stability with tolerable energy drain from the kinetic stabilizer. Then MHD stable systems are analysed for stability of the trapped particle mode. This mode is characterized by the detachment of the central-cell plasma from the kinetic-stabilizer region without inducing field-line bending. Stability of the trapped particle mode is sensitive to the electron connection between the stabilizer and the end plug. It is found that the stability condition for the trapped particle mode is more constraining than the stability condition for the MHD mode, and it is challenging to satisfy the required power constraint. Furthermore, a severe power drain may arise from the necessary connection of low-energy electrons in the kinetic stabilizer to the central region.

Frequency stabilization of a 1083 nm fiber laser to {sup 4}He transition lines with optical heterodyne saturation spectroscopies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, W.; Peng, X., E-mail: xiangpeng@pku.edu.cn; Li, W.

2014-07-15

Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable {sup 4}He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to itsmore » flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10{sup −12}@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.« less

Structural Stabilities of β-Ti Alloys Studied Using a New Mo Equivalent Derived from [ β/( α + β)] Phase-Boundary Slopes

NASA Astrophysics Data System (ADS)

Wang, Qing; Dong, Chuang; Liaw, Peter K.

2015-08-01

Structural stabilities of β-Ti alloys are generally investigated by an empirical Mo equivalent, which quantifies the stability contribution of each alloying element, M, in comparison to that of the major β-Ti stabilizer, Mo. In the present work, a new Mo equivalent (Moeq)Q is proposed, which uses the slopes of the boundary lines between the β and ( α + β) phase zones in binary Ti-M phase diagrams. This (Moeq)Q reflects a simple fact that the β-Ti stability is enhanced, when the β phase zone is enlarged by a β-Ti stabilizer. It is expressed as (Moeq)Q = 1.0 Mo + 0.74 V + 1.01 W + 0.23 Nb + 0.30 Ta + 1.23 Fe + 1.10 Cr + 1.09 Cu + 1.67 Ni + 1.81 Co + 1.42 Mn + 0.38 Sn + 0.34 Zr + 0.99 Si - 0.57 Al (at. pct), where the equivalent coefficient of each element is the slope ratio of the [ β/( α + β)] boundary line of the binary Ti-M phase diagram to that of the Ti-Mo. This (Moeq)Q is shown to reliably characterize the critical stability limit of multi-component β-Ti alloys with low Young's moduli, where the critical lower limit for β stabilization is (Moeq)Q = 6.25 at. pct or 11.8 wt pct Mo.

Management of pediatric mandibular fractures using bioresorbable plating system - Efficacy, stability, and clinical outcomes: Our experiences and literature review.

PubMed

Singh, Mahinder; Singh, R K; Passi, Deepak; Aggarwal, Mohit; Kaur, Guneet

2016-01-01

The purpose of this study was to determine the efficacy and stability of the biodegradable fixation system for treatment of mandible fractures in pediatric patients by measuring the bite force. Sixty pediatric patients with mandibular fractures (36 males, 24 females) were included in this study. The 2.5-mm resorbable plates were adapted along Champy's line of ideal osteosynthesis and secured with four 2.5 mm diameter monocortical resorbable screws, 8 mm in length. All patients were followed for 10 months. Clinical parameters, such as soft tissue infection, nonunion, malunion, implant exposure, malocclusion, nerve injury, and bite force for stability, were prospectively assessed. Adequate fixation and primary bone healing was achieved in 100% of the cases. Six minor complications (10%) were observed: 2 soft tissue infections (3%), 1 plate dehiscence (2%), 1 malocclusion (2%), and 2 paresthesia (3%). 2.5-mm resorbable plating system along Champy's line of ideal osteosynthesis is a good treatment modality for mandible fractures in pediatric patients.

Improvement of the antiproliferative effect of rapamycin on tumor cell lines by poly (monomethylitaconate)-based pH-sensitive, plasma stable liposomes.

PubMed

Ghanbarzadeh, Saeed; Arami, Sanam; Pourmoazzen, Zhaleh; Khorrami, Arash

2014-03-01

pH-responsive polymers produce liposomes with pH-sensitive property which can release their encapsulated drug under mild acidic conditions found inside the cellular endosomes, inflammatory tissues and cancerous cells. The aim of this study was preparing pH-sensitive and plasma stable liposomes in order to enhance the selectivity and antiproliferative effect of Rapamycin. In the present study we used PEG-poly (monomethylitaconate)-CholC6 (PEG-PMMI-CholC6) copolymer and Oleic acid (OA) to induce pH-sensitive property in Rapamycin liposomes. pH-sensitive liposomal formulations bearing copolymer PEG-PMMI-CholC6 and OA were characterized in regard to physicochemical stability, pH-responsiveness and stability in human plasma. The ability of pH-sensitive liposomes in enhancing the cytotoxicity of Rapamycin was evaluated in vitro by using colon cancer cell line (HT-29) and compared with its cytotoxicity on human umbilical vein endothelial cell (HUVEC) line. Both formulations were found to release their contents under mild acidic conditions rapidly. However, unlike OA-based liposomes, the PEG-PMMI-CholC6 bearing liposomes preserved their pH-sensitivity in plasma. Both types of pH-sensitive Rapamycin-loaded liposomes exhibited high physicochemical stability and could deliver antiproliferative agent into HT-29 cells much more efficiently in comparison with conventional liposomes. Conversely, the antiproliferative effect of pH-sensitive liposomes on HUVEC cell line was less than conventional liposomes. This study showed that both OA and PEG-PMMI-CholC6-based vesicles could submit pH-sensitive property, however, only PEG-PMMI-CholC6-based liposomes could preserve pH-sensitive property after incubation in plasma. As a result pH-sensitive PEG-PMMI-CholC6-based liposomal formulation can improve the selectivity, stability and antiproliferative effect of Rapamycin. Copyright © 2014 Elsevier B.V. All rights reserved.

46 CFR 35.20-7 - Verification of vessel compliance with applicable stability requirements-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the vessels's trim and stability book, stability letter, Certificate of Inspection, and Load Line.... (b) When determining compliance with applicable stability requirements the vessel's draft, trim, and...

46 CFR 35.20-7 - Verification of vessel compliance with applicable stability requirements-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the vessels's trim and stability book, stability letter, Certificate of Inspection, and Load Line.... (b) When determining compliance with applicable stability requirements the vessel's draft, trim, and...

Spectral and temporal characterization of a fused-quartz-microresonator optical frequency comb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papp, Scott B.; Diddams, Scott A.

2011-11-15

We report on the fabrication of high-Q, fused-quartz microresonators and the parametric generation of a frequency comb with 36-GHz line spacing using them. We have characterized the intrinsic stability of the comb in both the time and frequency domains to assess its suitability for future precision metrology applications. Intensity autocorrelation measurements and line-by-line comb control reveal near-transform-limited picosecond pulse trains that are associated with good relative phase and amplitude stability of the comb lines. The comb's 36-GHz line spacing can be readily photodetected, which enables measurements of its intrinsic and absolute phase fluctuations.

Stability of the line preserving flows

NASA Astrophysics Data System (ADS)

Figura, Przemysław

2017-11-01

We examine the equations that are used to describe flows which preserve field lines. We study what happens if we introduce perturbations to the governing equations. The stability of the line preserving flows in the case of the magneto-fluids permeated by magnetic fields is strictly connected to the non-null magnetic reconnection processes. In most of our study we use the Euler potential representation of the external magnetic field. We provide general expressions for the perturbations of the Euler potentials that describe the magnetic field. Similarly, we provide expressions for the case of steady flow as well as we obtain certain conditions required for the stability of the flow. In addition, for steady flows we formulate conditions under which the perturbations of the external field are negligible and the field may be described by its initial unperturbed form. Then we consider the flow equation that transforms quantities from the laboratory coordinate system to the related external field coordinate system. We introduce perturbations to the equation and obtain its simplified versions for the case of a steady flow. For a given system, use of this method allows us to simplify the considerations provided that some part of the system may be described as a perturbation. Next, to study regions favourable for the magnetic reconnection to occur we introduce a deviation vector to the basic line preserving flows condition equation. We provide expressions of the vector for some simplifying cases. This method allows us to examine if given perturbations either stabilise the system or induce magnetic reconnection. To illustrate some of our results we study two examples, namely a simple laboratory plasma flow and a simple planetary magnetosphere model.

Environmental Stability of Seed Carbohydrate Profiles in Soybeans Containing Different Alleles of the Raffinose Synthase 2 (RS2) Gene.

PubMed

Bilyeu, Kristin D; Wiebold, William J

2016-02-10

Soybean [Glycine max (L.) Merr.] is important for the high protein meal used for livestock feed formulations. Carbohydrates contribute positively or negatively to the potential metabolizable energy in soybean meal. The positive carbohydrate present in soybean meal consists primarily of sucrose, whereas the negative carbohydrate components are the raffinose family of oligosaccharides (RFOs), raffinose and stachyose. Increasing sucrose and decreasing raffinose and stachyose are critical targets to improve soybean. In three recently characterized lines, variant alleles of the soybean raffinose synthase 2 (RS2) gene were associated with increased sucrose and decreased RFOs. The objective of this research was to compare the environmental stability of seed carbohydrates in soybean lines containing wild-type or variant alleles of RS2 utilizing a field location study and a date of planting study. The results define the carbohydrate variation in distinct regional and temporal environments using soybean lines with different alleles of the RS2 gene.

Evaluation of Hose in Hose Transfer Line Service Life for Hanfords Interim Stabilization Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

TORRES, T.D.

RPP-6153, Engineering Task Plan for Hose-in-Hose Transfer System for the Interim Stabilization Program (Torres, 2000a), defines the programmatic goals, functional requirements, and technical criteria for the development and subsequent installation of waste transfer line equipment to support Hanford's Interim Stabilization Program. RPP-6028, Specification for Hose in Hose Transfer Lines for Hanford's Interim Stabilization Program (Torres, 2000b), has been issued to define the specific requirements for the design, manufacture, and verification of transfer line assemblies for specific waste transfer applications associated with Interim Stabilization. Included in RPP-6028 are tables defining the chemical constituents of concern to which transfer lines will bemore » exposed. Current Interim Stabilization Program planning forecasts that the at-grade transfer lines will be required to convey pumpable waste for as much as three years after commissioning, RPP-6028 Section 3.2.7. Performance Incentive Number ORP-05 requires that all the Single Shell Tanks be Interim Stabilized by September 30, 2003. The Tri-Party Agreement (TPA) milestone M-41-00, enforced by a federal consent decree, requires all the Single Shell Tanks to be Interim stabilized by September 30, 2004. By meeting the Performance Incentive the TPA milestone is met. Prudent engineering dictates that the equipment used to transfer waste have a life in excess of the forecasted operational time period, with some margin to allow for future adjustments to the planned schedule. This document evaluates the effective service life of the Hose-in-Hose Transfer Lines, based on information submitted by the manufacturer, published literature and calculations. The effective service life of transfer line assemblies is a function of several factors. Foremost among these are the hose material's resistance to the harmful effects of process fluid characteristics, ambient environmental conditions, exposure to ionizing radiation and the manufacturer's stated shelf life. In order to determine the transfer line service life this evaluation examines the certification of shelf life, the certification of chemical compatibility with waste, catalog information of ambient ratings and published literature on the effects of exposure to ionizing radiation on the mechanical properties of elastomeric materials. During initial hose procurements, the hose-in-hose transfer line vendor River Bend Hose Specialty (RBHS) submitted a letter, dated 6/8/00, which recommended the service and shelf life of the hose to be seven years. In submittals for later hose procurements, RBHS submitted a letter, dated 11/6/00, which recommended the service life of the hose to be three years. This submittal was followed by documentation, on 2/14/01, which submitted new storage requirements and restated the seven year shelf life. RBHS revised their original hose service life estimate to a more conservative three years due to concerns over the effects of chemicals in transferred waste. The above mentioned submittals from RBHS are the primary drivers of the three year service life limit established by this document.« less

On-Line Robust Modal Stability Prediction using Wavelet Processing

NASA Technical Reports Server (NTRS)

Brenner, Martin J.; Lind, Rick

1998-01-01

Wavelet analysis for filtering and system identification has been used to improve the estimation of aeroservoelastic stability margins. The conservatism of the robust stability margins is reduced with parametric and nonparametric time- frequency analysis of flight data in the model validation process. Nonparametric wavelet processing of data is used to reduce the effects of external disturbances and unmodeled dynamics. Parametric estimates of modal stability are also extracted using the wavelet transform. Computation of robust stability margins for stability boundary prediction depends on uncertainty descriptions derived from the data for model validation. The F-18 High Alpha Research Vehicle aeroservoelastic flight test data demonstrates improved robust stability prediction by extension of the stability boundary beyond the flight regime. Guidelines and computation times are presented to show the efficiency and practical aspects of these procedures for on-line implementation. Feasibility of the method is shown for processing flight data from time- varying nonstationary test points.

In line monitoring of the preparation of water-in-oil-in-water (W/O/W) type multiple emulsions via dielectric spectroscopy.

PubMed

Beer, Sebastian; Dobler, Dorota; Gross, Alexander; Ost, Martin; Elseberg, Christiane; Maeder, Ulf; Schmidts, Thomas Michael; Keusgen, Michael; Fiebich, Martin; Runkel, Frank

2013-01-30

Multiple emulsions offer various applications in a wide range of fields such as pharmaceutical, cosmetics and food technology. Two features are known to yield a great influence on multiple emulsion quality and utility as encapsulation efficiency and prolonged stability. To achieve a prolonged stability, the production of the emulsions has to be observed and controlled, preferably in line. In line measurements provide available parameters in a short time frame without the need for the sample to be removed from the process stream, thereby enabling continuous process control. In this study, information about the physical state of multiple emulsions obtained from dielectric spectroscopy (DS) is evaluated for this purpose. Results from dielectric measurements performed in line during the production cycle are compared to theoretically expected results and to well established off line measurements. Thus, a first step to include the production of multiple emulsions into the process analytical technology (PAT) guidelines of the Food and Drug Administration (FDA) is achieved. DS proved to be beneficial in determining the crucial stopping criterion, which is essential in the production of multiple emulsions. The stopping of the process at a less-than-ideal point can severely lower the encapsulation efficiency and the stability, thereby lowering the quality of the emulsion. DS is also expected to provide further information about the multiple emulsion like encapsulation efficiency. Copyright © 2012 Elsevier B.V. All rights reserved.

Linear Stability of Binary Alloy Solidification for Unsteady Growth Rates

NASA Technical Reports Server (NTRS)

Mazuruk, K.; Volz, M. P.

2010-01-01

An extension of the Mullins and Sekerka (MS) linear stability analysis to the unsteady growth rate case is considered for dilute binary alloys. In particular, the stability of the planar interface during the initial solidification transient is studied in detail numerically. The rapid solidification case, when the system is traversing through the unstable region defined by the MS criterion, has also been treated. It has been observed that the onset of instability is quite accurately defined by the "quasi-stationary MS criterion", when the growth rate and other process parameters are taken as constants at a particular time of the growth process. A singular behavior of the governing equations for the perturbed quantities at the constitutional supercooling demarcation line has been observed. However, when the solidification process, during its transient, crosses this demarcation line, a planar interface is stable according to the linear analysis performed.

Matching technique yields optimum LNA performance. [Low Noise Amplifiers

NASA Technical Reports Server (NTRS)

Sifri, J. D.

1986-01-01

The present article is concerned with a case in which an optimum noise figure and unconditional stability have been designed into a 2.385-GHz low-noise preamplifier via an unusual method for matching the input with a suspended line. The results obtained with several conventional line-matching techniques were not satisfactory. Attention is given to the minimization of thermal noise, the design procedure, requirements for a high-impedance line, a sampling of four matching networks, the noise figure of the single-line matching network as a function of frequency, and the approaches used to achieve unconditional stability.

Production of Low Cost Carbon-Fiber through Energy Optimization of Stabilization Process.

PubMed

Golkarnarenji, Gelayol; Naebe, Minoo; Badii, Khashayar; Milani, Abbas S; Jazar, Reza N; Khayyam, Hamid

2018-03-05

To produce high quality and low cost carbon fiber-based composites, the optimization of the production process of carbon fiber and its properties is one of the main keys. The stabilization process is the most important step in carbon fiber production that consumes a large amount of energy and its optimization can reduce the cost to a large extent. In this study, two intelligent optimization techniques, namely Support Vector Regression (SVR) and Artificial Neural Network (ANN), were studied and compared, with a limited dataset obtained to predict physical property (density) of oxidative stabilized PAN fiber (OPF) in the second zone of a stabilization oven within a carbon fiber production line. The results were then used to optimize the energy consumption in the process. The case study can be beneficial to chemical industries involving carbon fiber manufacturing, for assessing and optimizing different stabilization process conditions at large.

Production of Low Cost Carbon-Fiber through Energy Optimization of Stabilization Process

PubMed Central

Golkarnarenji, Gelayol; Naebe, Minoo; Badii, Khashayar; Milani, Abbas S.; Jazar, Reza N.; Khayyam, Hamid

2018-01-01

To produce high quality and low cost carbon fiber-based composites, the optimization of the production process of carbon fiber and its properties is one of the main keys. The stabilization process is the most important step in carbon fiber production that consumes a large amount of energy and its optimization can reduce the cost to a large extent. In this study, two intelligent optimization techniques, namely Support Vector Regression (SVR) and Artificial Neural Network (ANN), were studied and compared, with a limited dataset obtained to predict physical property (density) of oxidative stabilized PAN fiber (OPF) in the second zone of a stabilization oven within a carbon fiber production line. The results were then used to optimize the energy consumption in the process. The case study can be beneficial to chemical industries involving carbon fiber manufacturing, for assessing and optimizing different stabilization process conditions at large. PMID:29510592

Evaluating competing forces constraining glacial grounding-line stability (Invited)

NASA Astrophysics Data System (ADS)

Powell, R. D.

2013-12-01

Stability of grounding lines of marine-terminating glaciers and ice sheets is of concern due to their importance in governing rates of ice mass loss and consequent sea level rise during global warming. Although processes are similar at tidewater and floating grounding zones their relative magnitudes in terms of their influence on grounding-line stability vary between these two end members. Processes considered Important for this discussion are ice dynamics, ice surface melting and crevassing, ocean dynamics, subglacial sediment and water dynamics, and subglacial bed geometries. Models have continued to improve in their representation of these complex interactions but reliable field measurements and data continue to be hard earned and too few to properly constrain the range of boundary conditions in this complicated system. Some data will be presented covering a range of regimes from Alaska, Svalbard and Antarctica. Certainly more data are required on subglacial sediment/water dynamics and fluxes to fully represent the spectrum of glacial regimes and to assess the significance of grounding-zone sediment systems in counteracting the other processes to force grounding-line stability. Especially important here is constraining the duration of the stability that could be maintained by sediment flux - present data appear to show that it is likely to be a limited period.

Direct Simulation of Evolution and Control of Three-Dimensional Instabilities in Attachment-Line Boundary Layers

NASA Technical Reports Server (NTRS)

Joslin, Ronald D.

1995-01-01

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier-Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic- source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in at-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

PARTIAL RESTRAINING FORCE INTRODUCTION METHOD FOR DESIGNING CONSTRUCTION COUNTERMESURE ON ΔB METHOD

NASA Astrophysics Data System (ADS)

Nishiyama, Taku; Imanishi, Hajime; Chiba, Noriyuki; Ito, Takao

Landslide or slope failure is a three-dimensional movement phenomenon, thus a three-dimensional treatment makes it easier to understand stability. The ΔB method (simplified three-dimensional slope stability analysis method) is based on the limit equilibrium method and equals to an approximate three-dimensional slope stability analysis that extends two-dimensional cross-section stability analysis results to assess stability. This analysis can be conducted using conventional spreadsheets or two-dimensional slope stability computational software. This paper describes the concept of the partial restraining force in-troduction method for designing construction countermeasures using the distribution of the restraining force found along survey lines, which is based on the distribution of survey line safety factors derived from the above-stated analysis. This paper also presents the transverse distributive method of restraining force used for planning ground stabilizing on the basis of the example analysis.

Laser heterodyne spectrometer for helioseismology

NASA Technical Reports Server (NTRS)

Glenar, D. A.; Deming, D.; Espenak, F.; Kostiuk, T.; Mumma, M. J.

1986-01-01

The technique of laser heterodyne spectroscopy has been applied to the measurement of solar oscillations. Coherent mixing of solar radiation with the output of a frequency-stabilized CO2 laser permits the measurement of fully resolved profiles of solar absorption lines with high spectral purity and excellent frequency stability. This technique has been used to measure OH pure rotation lines in the infrared solar spectrum. Power spectra of these line frequency measurements show the well-known 5-min oscillations as well as significant velocity power at shorter periods.

Micromachined silicon acoustic delay line with improved structural stability and acoustic directivity for real-time photoacoustic tomography

NASA Astrophysics Data System (ADS)

Cho, Young; Kumar, Akhil; Xu, Song; Zou, Jun

2017-03-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. However, as its length increases to provide longer delay time, the delay line becomes more vulnerable to structural instability due to reduced mechanical stiffness. In addition, the small cross-section area of the delay line results in a large acoustic acceptance angle and therefore poor directivity. To address these two issues, this paper reports the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, a new tapered design for the input terminal of the delay line was also investigate to improve its acoustic directivity by reducing the acoustic acceptance angle. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

Nuclear-coupled thermal-hydraulic stability analysis of boiling water reactors

NASA Astrophysics Data System (ADS)

Karve, Atul A.

We have studied the nuclear-coupled thermal-hydraulic stability of boiling water reactors (BWRs) using a model we developed from: the space-time modal neutron kinetics equations based on spatial omega-modes, the equations for two-phase flow in parallel boiling channels, the fuel rod heat conduction equations, and a simple model for the recirculation loop. The model is represented as a dynamical system comprised of time-dependent nonlinear ordinary differential equations, and it is studied using stability analysis, modern bifurcation theory, and numerical simulations. We first determine the stability boundary (SB) in the most relevant parameter plane, the inlet-subcooling-number/external-pressure-drop plane, for a fixed control rod induced external reactivity equal to the 100% rod line value and then transform the SB to the practical power-flow map. Using this SB, we show that the normal operating point at 100% power is very stable, stability of points on the 100% rod line decreases as the flow rate is reduced, and that points are least stable in the low-flow/high-power region. We also determine the SB when the modal kinetics is replaced by simple point reactor kinetics and show that the first harmonic mode has no significant effect on the SB. Later we carry out the relevant numerical simulations where we first show that the Hopf bifurcation, that occurs as a parameter is varied across the SB is subcritical, and that, in the important low-flow/high-power region, growing oscillations can result following small finite perturbations of stable steady-states on the 100% rod line. Hence, a point on the 100% rod line in the low-flow/high-power region, although stable, may nevertheless be a point at which a BWR should not be operated. Numerical simulations are then done to calculate the decay ratios (DRs) and frequencies of oscillations for various points on the 100% rod line. It is determined that the NRC requirement of DR < 0.75-0.8 is not rigorously satisfied in the low-flow/high-power region and hence these points should be avoided during normal startup and shutdown operations. The frequency of oscillation is shown to decrease as the flow rate is reduced and the frequency of 0.5Hz observed in the low-flow/high-power region is consistent with those observed during actual instability incidents. Additional numerical simulations show that in the low-flow/high-power region, for the same initial conditions, the use of point kinetics leads to damped oscillations, whereas the model that includes the modal kinetics equations results in growing nonlinear oscillations. Thus, we show that side-by-side out-of-phase growing power oscillations result due to the very important first harmonic mode effect and that the use of point kinetics, which fails to predict these growing oscillations, leads to dramatically nonconservative results. Finally, the effect of a simple recirculation loop model that we develop is studied by carrying out additional stability analyses and additional numerical simulations. It is shown that the loop has a stabilizing effect on certain points on the 100% rod line for time delays equal to integer multiples of the natural period of oscillation, whereas it has a destabilizing effect for half-integer multiples. However, for more practical time delays, it is determined that the overall effect generally is destabilizing.

A Study on Multi-Swing Stability Analysis of Power System using Damping Rate Inversion

NASA Astrophysics Data System (ADS)

Tsuji, Takao; Morii, Yuki; Oyama, Tsutomu; Hashiguchi, Takuhei; Goda, Tadahiro; Nomiyama, Fumitoshi; Kosugi, Narifumi

In recent years, much attention is paid to the nonlinear analysis method in the field of stability analysis of power systems. Especially for the multi-swing stability analysis, the unstable limit cycle has an important meaning as a stability margin. It is required to develop a high speed calculation method of stability boundary regarding multi-swing stability because the real-time calculation of ATC is necessary to realize the flexible wheeling trades. Therefore, the authors have developed a new method which can calculate the unstable limit cycle based on damping rate inversion method. Using the unstable limit cycle, it is possible to predict the multi-swing stability at the time when the fault transmission line is reclosed. The proposed method is tested in Lorenz equation, single-machine infinite-bus system model and IEEJ WEST10 system model.

Management of pediatric mandibular fractures using bioresorbable plating system – Efficacy, stability, and clinical outcomes: Our experiences and literature review

PubMed Central

Singh, Mahinder; Singh, R.K.; Passi, Deepak; Aggarwal, Mohit; Kaur, Guneet

2015-01-01

Aims The purpose of this study was to determine the efficacy and stability of the biodegradable fixation system for treatment of mandible fractures in pediatric patients by measuring the bite force. Methods Sixty pediatric patients with mandibular fractures (36 males, 24 females) were included in this study. The 2.5-mm resorbable plates were adapted along Champy's line of ideal osteosynthesis and secured with four 2.5 mm diameter monocortical resorbable screws, 8 mm in length. All patients were followed for 10 months. Clinical parameters, such as soft tissue infection, nonunion, malunion, implant exposure, malocclusion, nerve injury, and bite force for stability, were prospectively assessed. Results Adequate fixation and primary bone healing was achieved in 100% of the cases. Six minor complications (10%) were observed: 2 soft tissue infections (3%), 1 plate dehiscence (2%), 1 malocclusion (2%), and 2 paresthesia (3%). Conclusion 2.5-mm resorbable plating system along Champy's line of ideal osteosynthesis is a good treatment modality for mandible fractures in pediatric patients. PMID:27195206

KELVIN–HELMHOLTZ INSTABILITY IN SOLAR CHROMOSPHERIC JETS: THEORY AND OBSERVATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuridze, D.; Henriques, V.; Mathioudakis, M.

2016-10-20

Using data obtained by the high-resolution CRisp Imaging SpectroPolarimeter instrument on the Swedish 1 m Solar Telescope, we investigate the dynamics and stability of quiet-Sun chromospheric jets observed at the disk center. Small-scale features, such as rapid redshifted and blueshifted excursions, appearing as high-speed jets in the wings of the H α line, are characterized by short lifetimes and rapid fading without any descending behavior. To study the theoretical aspects of their stability without considering their formation mechanism, we model chromospheric jets as twisted magnetic flux tubes moving along their axis, and use the ideal linear incompressible magnetohydrodynamic approximation tomore » derive the governing dispersion equation. Analytical solutions of the dispersion equation indicate that this type of jet is unstable to Kelvin–Helmholtz instability (KHI), with a very short (few seconds) instability growth time at high upflow speeds. The generated vortices and unresolved turbulent flows associated with the KHI could be observed as a broadening of chromospheric spectral lines. Analysis of the H α line profiles shows that the detected structures have enhanced line widths with respect to the background. We also investigate the stability of a larger-scale H α jet that was ejected along the line of sight. Vortex-like features, rapidly developing around the jet’s boundary, are considered as evidence of the KHI. The analysis of the energy equation in the partially ionized plasma shows that ion–neutral collisions may lead to fast heating of the KH vortices over timescales comparable to the lifetime of chromospheric jets.« less

A methodology to study the possible occurrence of chugging in liquid rocket engines during transient start-up

NASA Astrophysics Data System (ADS)

Leonardi, Marco; Nasuti, Francesco; Di Matteo, Francesco; Steelant, Johan

2017-10-01

An investigation on the low frequency combustion instabilities due to the interaction of combustion chamber and feed line dynamics in a liquid rocket engine is carried out implementing a specific module in the system analysis software EcosimPro. The properties of the selected double time lag model are identified according to the two classical assumptions of constant and variable time lag. Module capabilities are evaluated on a literature experimental set up consisting of a combustion chamber decoupled from the upstream feed lines. The computed stability map results to be in good agreement with both experimental data and analytical models. Moreover, the first characteristic frequency of the engine is correctly predicted, giving confidence on the use of the module for the analysis of chugging instabilities. As an example of application, a study is carried out on the influence of the feed lines on the system stability, correctly capturing that the lines extend the stable regime of the combustion chamber and that the propellant domes play a key role in coupling the dynamics of combustion chamber and feed lines. A further example is presented to discuss on the role of pressure growth rate and of the combustion chamber properties on the possible occurrence of chug instability during engine start-up and on the conditions that lead to its damping or growth.

Characterization of a highly efficient chevron-shaped anti-contamination device

NASA Astrophysics Data System (ADS)

Fiore, M.; Vermeersch, O.; Forte, M.; Casalis, G.; François, C.

2016-04-01

This paper is devoted to the characterization of an optimized chevron-shaped anti-contamination device (ACD). This device can prevent efficiently the propagation of turbulence from the fuselage along the attachment line (hypothetical streamline that spreads the flow going to suction side and the one going to pressure side) of swept wings and enables the development of a new laminar boundary layer downstream. More specifically, the aim is to prevent boundary-layer transition along the attachment line by a contamination process. This process is characterized by the typical Reynolds number overline{R} and the associated Poll's criterion. Thus, ACD efficiency will be expressed in terms of overline{R} values. Some experiments performed on a new numerically optimized ACD have shown its ability to prevent leading-edge contamination up to overline{R} values close to the natural transition process of the laminar boundary layer along the attachment line. The corresponding stability analysis of the laminar boundary layer is made using the Görtler-Hämmerlin stability approach. The study is completed with the different transition processes that can occur downstream the attachment line, around the airfoil, especially with crossflow analysis.

Investigations on effects of the hole size to fix electrodes and interconnection lines in polydimethylsiloxane

NASA Astrophysics Data System (ADS)

Behkami, Saber; Frounchi, Javad; Ghaderi Pakdel, Firouz; Stieglitz, Thomas

2017-11-01

Translational research in bioelectronics medicine and neural implants often relies on established material assemblies made of silicone rubber (polydimethylsiloxane-PDMS) and precious metals. Longevity of the compound is of utmost importance for implantable devices in therapeutic and rehabilitation applications. Therefore, secure mechanical fixation can be used in addition to chemical bonding mechanisms to interlock PDMS substrate and insulation layers with metal sheets for interconnection lines and electrodes. One of the best ways to fix metal lines and electrodes in PDMS is to design holes in electrode rims to allow for direct interconnection between top to bottom layer silicone. Hence, the best layouts and sizes of holes (up to 6) which provide sufficient stability against lateral and vertical forces have been investigated with a variety of numbers of hole in line electrodes, which are simulated and fabricated with different layouts, sizes and materials. Best stability was obtained with radii of 100, 72 and 62 µm, respectively, and a single central hole in aluminum, platinum and MP35N foil line electrodes of 400  ×  500 µm2 size and of thickness 20 µm. The study showed that the best hole size which provides line electrode immobility (of thickness less than 30 µm) within a central hole is proportional to reverse value of Young’s Modulus of the material used. Thus, an array of line electrodes was designed and fabricated to study this effect. Experimental results were compared with simulation data. Subsequently, an approximation curve was generated as design rule to propose the best radius to fix line electrodes according to the material thickness between 10 and 200 µm using PDMS as substrate material.

Genetic analyses of Per.C6 cell clones producing a therapeutic monoclonal antibody regarding productivity and long-term stability.

PubMed

Tsuruta, Lilian Rumi; Lopes Dos Santos, Mariana; Yeda, Fernanda Perez; Okamoto, Oswaldo Keith; Moro, Ana Maria

2016-12-01

Genetic characterization of protein-producing clones represents additional value to cell line development. In the present study, ten Per.C6 clones producing a Rebmab100 monoclonal antibody were selected using two cloning methods: six clones originated from limiting dilution cloning and four by the automated colony picker ClonePix FL. A stability program was performed for 50 generations, including 4 batches distributed along the timeframe to determine specific productivity (Qp) maintenance. Four stable clones (two from limiting dilution and two from ClonePix FL) were further evaluated. The relative mRNA expression levels of both heavy chain (HC) and light chain (LC) genes were verified at generations 0, 30-35, and 50-55 of the stability program. At generations 0 and 30-35, LC gene expression level was higher than HC gene, whereas at generation 50-55, the opposite prevailed. A high correlation was observed between Qp and HC or LC mRNA expression level for all clones at each generation analyzed along the continuous culture. The mRNA stability study was performed at steady-state culture. The LC gene displayed a higher half-life and lower decay constant than HC gene, accounting for the higher observed expression level of LC mRNA in comparison to HC mRNA. Clone R6 was highlighted due its high Qp, mRNA expression levels, and mRNA stability. Besides the benefits of applying genetic characterization for the selection of stable and high-producing clones, the present study shows for the first time the correlation between Qp and HC or LC expression levels and also mRNA stability in clones derived from human cell line Per.C6(®).

Variable TERRA abundance and stability in cervical cancer cells.

PubMed

Oh, Bong-Kyeong; Keo, Ponnarath; Bae, Jaeman; Ko, Jung Hwa; Choi, Joong Sub

2017-06-01

Telomeres are transcribed into long non-coding RNA, referred to as telomeric repeat-containing RNA (TERRA), which plays important roles in maintaining telomere integrity and heterochromatin formation. TERRA has been well characterized in HeLa cells, a type of cervical cancer cell. However, TERRA abundance and stability have not been examined in other cervical cancer cells, at least to the best of our knowledge. Thus, in this study, we measured TERRA levels and stability, as well as telomere length in 6 cervical cancer cell lines, HeLa, SiHa, CaSki, HeLa S3, C-33A and SNU-17. We also examined the association between the TERRA level and its stability and telomere length. We found that the TERRA level was several fold greater in the SiHa, CaSki, HeLa S3, C-33A and SNU-17 cells, than in the HeLa cells. An RNA stability assay of actinomycin D-treated cells revealed that TERRA had a short half-life of ~4 h in HeLa cells, which was consistent with previous studies, but was more stable with a longer half-life (>8 h) in the other 5 cell lines. Telomere length varied from 4 to 9 kb in the cells and did not correlate significantly with the TERRA level. On the whole, our data indicate that TERRA abundance and stability vary between different types of cervical cancer cells. TERRA degrades rapidly in HeLa cells, but is maintained stably in other cervical cancer cells that accumulate higher levels of TERRA. TERRA abundance is associated with the stability of RNA in cervical cancer cells, but is unlikely associated with telomere length.

Direct Simulation of Evolution and Control of Nonlinear Instabilities in Attachment-Line Boundary Layers

NASA Technical Reports Server (NTRS)

Joslin, Ronald D.

2004-01-01

The unsteady, incompressible Navier-Stokes equations are used for the direct numerical simulation (DNS) of spatially evolving disturbances in a three-dimensional (3-D) attachment-line boundary layer. Two-dimensional (2-D) disturbances are introduced either by forcing at the in ow or by harmonic-source generators at the wall; 3-D disturbances are introduced by harmonic-source generators at the wall. The DNS results are in good agreement with both 2-D non-parallel theory (for small-amplitude disturbances) and weakly nonlinear theory (for finite-amplitude disturbances), which validates the two theories. The 2-D DNS results indicate that nonlinear disturbance growth occurs near branch II of the neutral stability curve; however, steady suction can be used to stabilize this disturbance growth. For 3-D instabilities that are generated o the attachment line, spreading both toward and away from the attachment line causes energy transfer to the attachment-line and downstream instabilities; suction stabilizes these instabilities. Furthermore, 3-D instabilities are more stable than 2-D or quasi-2-D instabilities.

Micromachined silicon acoustic delay line with 3D-printed micro linkers and tapered input for improved structural stability and acoustic directivity

NASA Astrophysics Data System (ADS)

Cho, Y.; Kumar, A.; Xu, S.; Zou, J.

2016-10-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. To achieve deeper imaging depth and wider field of view, a longer delay time and therefore delay length are required. However, as the length of the delay line increases, it becomes more vulnerable to structural instability due to reduced mechanical stiffness. In this paper, we report the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, the improvement of the acoustic acceptance angle of the silicon acoustic delay lines was also investigated to better suppress the reception of unwanted ultrasound signals outside of the imaging plane. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

Structural, quantum chemical, vibrational and thermal studies of a hydrogen bonded zwitterionic co-crystal (nicotinic acid: pyrogallol)

NASA Astrophysics Data System (ADS)

Prabha, E. Arockia Jeya Yasmi; Kumar, S. Suresh; Athimoolam, S.; Sridhar, B.

2017-02-01

In the present work, a new co-crystal of nicotinic acid with pyrogallol (NICPY) has been grown in the zwitterionic form and the corresponding structural, vibrational, thermal, solubility and anti-cancer characteristics have been reported. The single crystal X-ray diffraction analysis confirms that the structural molecular packing of the crystal stabilized through N-H⋯O and O-H⋯O hydrogen bond. The stabilization energy of the hydrogen bond motifs were calculated in the solid state. Vibrational spectral studies such as Fourier transform-infrared (FT-IR) and FT-Raman were adopted to understand the zwitterionic co-crystalline nature of the compound, which has been compared with theoretically calculated vibrational frequencies. The thermal stability of the grown co-crystal was analyzed by TG/DTA study. The solubility of the NICPY co-crystal was investigated in water at different temperature and compared with that of the nicotinic acid, which is the parent compound of NICPY co-crystal. The grown crystals were treated with human cervical cancer cell line (HeLa) to analyze the cytotoxicity of NICPY crystals and compared with the parent compound, which shows that NICPY has moderate activity against human cervical cancer cell line.

Study of nonlinear liquid effects into ytterbium-doped fiber laser for multi-wavelength generation

NASA Astrophysics Data System (ADS)

Lozano-Hernandez, T.; Jauregui-Vazquez, D.; Estudillo-Ayala, J.; Herrera-Piad, L. A.; Rojas-Laguna, R.; Hernandez-Garcia, J. M.; Sierra-Hernandez, J. M.

2018-02-01

We present an experimental study of liquid refractive index effects into Ytterbium ring fiber laser cavity configuration. The laser is operated using a bi-tapered optical fiber immersed in water-alcohol concentrations. When the tapered fiber is dipped into a distilled water, a single lasing line with a peak power centered at 1025 nm is achieved. Afterward, by changing the polarization state into the cavity the lasing line can be switched. Moreover, by modifying the refractive index liquid surrounding media the lasing lines can be controlled and special liquid provide nonlinear response. The laser offers compactness, low effective cost and good stability.

Cavity ring-down spectroscopy of Doppler-broadened absorption line with sub-MHz absolute frequency accuracy.

PubMed

Cheng, C-F; Sun, Y R; Pan, H; Lu, Y; Li, X-F; Wang, J; Liu, A-W; Hu, S-M

2012-04-23

A continuous-wave cavity ring-down spectrometer has been built for precise determination of absolute frequencies of Doppler-broadened absorption lines. Using a thermo-stabilized Fabry-Pérot interferometer and Rb frequency references at the 780 nm and 795 nm, 0.1 - 0.6 MHz absolute frequency accuracy has been achieved in the 775-800 nm region. A water absorption line at 12579 cm(-1) is studied to test the performance of the spectrometer. The line position at zero-pressure limit is determined with an uncertainty of 0.3 MHz (relative accuracy of 0.8 × 10(-9)). © 2012 Optical Society of America

Simulation of Nonlinear Instabilities in an Attachment-Line Boundary Layer

NASA Technical Reports Server (NTRS)

Joslin, Ronald D.

1996-01-01

The linear and the nonlinear stability of disturbances that propagate along the attachment line of a three-dimensional boundary layer is considered. The spatially evolving disturbances in the boundary layer are computed by direct numerical simulation (DNS) of the unsteady, incompressible Navier-Stokes equations. Disturbances are introduced either by forcing at the in ow or by applying suction and blowing at the wall. Quasi-parallel linear stability theory and a nonparallel theory yield notably different stability characteristics for disturbances near the critical Reynolds number; the DNS results con rm the latter theory. Previously, a weakly nonlinear theory and computations revealed a high wave-number region of subcritical disturbance growth. More recent computations have failed to achieve this subcritical growth. The present computational results indicate the presence of subcritically growing disturbances; the results support the weakly nonlinear theory. Furthermore, an explanation is provided for the previous theoretical and computational discrepancy. In addition, the present results demonstrate that steady suction can be used to stabilize disturbances that otherwise grow subcritically along the attachment line.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

PubMed

Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas

2015-01-01

The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing

PubMed Central

2015-01-01

Background The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Methods Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. Results The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. Conclusion The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates. PMID:26192188

Flexible Launch Vehicle Stability Analysis Using Steady and Unsteady Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Bartels, Robert E.

2012-01-01

Launch vehicles frequently experience a reduced stability margin through the transonic Mach number range. This reduced stability margin can be caused by the aerodynamic undamping one of the lower-frequency flexible or rigid body modes. Analysis of the behavior of a flexible vehicle is routinely performed with quasi-steady aerodynamic line loads derived from steady rigid aerodynamics. However, a quasi-steady aeroelastic stability analysis can be unconservative at the critical Mach numbers, where experiment or unsteady computational aeroelastic analysis show a reduced or even negative aerodynamic damping.Amethod of enhancing the quasi-steady aeroelastic stability analysis of a launch vehicle with unsteady aerodynamics is developed that uses unsteady computational fluid dynamics to compute the response of selected lower-frequency modes. The response is contained in a time history of the vehicle line loads. A proper orthogonal decomposition of the unsteady aerodynamic line-load response is used to reduce the scale of data volume and system identification is used to derive the aerodynamic stiffness, damping, and mass matrices. The results are compared with the damping and frequency computed from unsteady computational aeroelasticity and from a quasi-steady analysis. The results show that incorporating unsteady aerodynamics in this way brings the enhanced quasi-steady aeroelastic stability analysis into close agreement with the unsteady computational aeroelastic results.

Linearized blade row compression component model. Stability and frequency response analysis of a J85-3 compressor

NASA Technical Reports Server (NTRS)

Tesch, W. A.; Moszee, R. H.; Steenken, W. G.

1976-01-01

NASA developed stability and frequency response analysis techniques were applied to a dynamic blade row compression component stability model to provide a more economic approach to surge line and frequency response determination than that provided by time-dependent methods. This blade row model was linearized and the Jacobian matrix was formed. The clean-inlet-flow stability characteristics of the compressors of two J85-13 engines were predicted by applying the alternate Routh-Hurwitz stability criterion to the Jacobian matrix. The predicted surge line agreed with the clean-inlet-flow surge line predicted by the time-dependent method to a high degree except for one engine at 94% corrected speed. No satisfactory explanation of this discrepancy was found. The frequency response of the linearized system was determined by evaluating its Laplace transfer function. The results of the linearized-frequency-response analysis agree with the time-dependent results when the time-dependent inlet total-pressure and exit-flow function amplitude boundary conditions are less than 1 percent and 3 percent, respectively. The stability analysis technique was extended to a two-sector parallel compressor model with and without interstage crossflow and predictions were carried out for total-pressure distortion extents of 180 deg, 90 deg, 60 deg, and 30 deg.

Stability and chaotification of vibration isolation floating raft systems with time-delayed feedback control.

PubMed

Li, Y L; Xu, D L; Fu, Y M; Zhou, J X

2011-09-01

This paper presents a systematic study on the stability of a two-dimensional vibration isolation floating raft system with a time-delayed feedback control. Based on the generalized Sturm criterion, the critical control gain for the delay-independent stability region and critical time delays for the stability switches are derived. The critical conditions can provide a theoretical guidance of chaotification design for line spectra reduction. Numerical simulations verify the correctness of the approach. Bifurcation analyses reveal that chaotification is more likely to occur in unstable region defined by these critical conditions, and the stiffness of the floating raft and mass ratio are the sensitive parameters to reduce critical control gain.

Effects of antioxidants on the quality and genomic stability of induced pluripotent stem cells

PubMed Central

Luo, Lan; Kawakatsu, Miho; Guo, Chao-Wan; Urata, Yoshishige; Huang, Wen-Jing; Ali, Haytham; Doi, Hanako; Kitajima, Yuriko; Tanaka, Takayuki; Goto, Shinji; Ono, Yusuke; Xin, Hong-Bo; Hamano, Kimikazu; Li, Tao-Sheng

2014-01-01

Effects of antioxidants on the quality and genomic stability of induced pluripotent stem (iPS) cells were investigated with two human iPS cell lines (201B7 and 253G1). Cells used in this study were expanded from a single colony of each cell line with the addition of proprietary antioxidant supplement or homemade antioxidant cocktail in medium, and maintained in parallel for 2 months. The cells grew well in all culture conditions and kept “stemness”. Although antioxidants modestly decreased the levels of intracellular reactive oxygen species, there were no differences in the expression of 53BP1 and pATM, two critical molecules related with DNA damage and repair, under various culture conditions. CGH analysis showed that the events of genetic aberrations were decreased only in the 253G1 iPS cells with the addition of homemade antioxidant cocktail. Long-term culture will be necessary to confirm whether low dose antioxidants improve the quality and genomic stability of iPS cells. PMID:24445363

Mode stabilization in quantum cascade lasers via an intra-cavity cascaded nonlinearity.

PubMed

St-Jean, M Renaudat; Amanti, M I; Bismuto, A; Beck, M; Faist, J; Sirtori, C

2017-02-06

We present self-stabilization of the inter-mode separation of a quantum cascade laser (QCL) emitting at 9 μm via cascaded second order nonlinearity. This effect has been observed in lasers that have the optical cavity embedded into a microwave strip-line. The intermodal beat note spectra narrow with increasing laser output power, up to less than 100 kHz. A flat frequency response to direct modulation up to 14 GHz is reported for these microstrip QCLs. The laser inter-mode spacing can be locked to an external RF signal and tuned by more than 1 MHz from the free-running spacing. A parallel study on the same laser material in a non-microstrip line waveguide shows superior performances of the microstrip QCL in terms of the intermodal spectral locking and stability. Finally by analyzing our results with the theory of the injection locking of coupled oscillators, we deduce that the microwave power injected in the microstrip QCL is 2 orders of magnitude higher than in the reference laser.

Noise properties of an optical frequency comb from a SESAM-mode-locked 1.5-μm solid-state laser stabilized to the 10-13 level

NASA Astrophysics Data System (ADS)

Schilt, S.; Dolgovskiy, V.; Bucalovic, N.; Schori, C.; Stumpf, M. C.; Di Domenico, G.; Pekarek, S.; Oehler, A. E. H.; Südmeyer, T.; Keller, U.; Thomann, P.

2012-11-01

We present a detailed investigation of the noise properties of an optical frequency comb generated from a femtosecond diode-pumped solid-state laser operating in the 1.5-μm spectral region. The stabilization of the passively mode-locked Er:Yb:glass laser oscillator, referred to as ERGO, is achieved using pump power modulation for the control of the carrier envelope offset (CEO) frequency and by adjusting the laser cavity length for the control of the repetition rate. The stability and the noise of the ERGO comb are characterized in free-running and in phase-locked operation by measuring the noise properties of the CEO, of the repetition rate, and of a comb line at 1558 nm. The comb line is analyzed from the heterodyne beat signal with a cavity-stabilized ultra-narrow-linewidth laser using a frequency discriminator. Two different schemes to stabilize the comb to a radio-frequency (RF) reference are compared. The comb properties (phase noise, frequency stability) are limited in both cases by the RF oscillator used to stabilize the repetition rate, while the contribution of the CEO is negligible at all Fourier frequencies, as a consequence of the low-noise characteristics of the CEO-beat. A linewidth of ≈150 kHz and a fractional frequency instability of 4.2×10-13 at 1 s are obtained for an optical comb line at 1558 nm. Improved performance is obtained by stabilizing the comb to an optical reference, which is a cavity-stabilized ultra-narrow linewidth laser at 1558 nm. The fractional frequency stability of 8×10-14 at 1 s, measured in preliminary experiments, is limited by the reference oscillator used in the frequency comparison.

Influence of damage and basal friction on the grounding line dynamics

NASA Astrophysics Data System (ADS)

Brondex, Julien; Gagliardini, Olivier; Gillet-Chaulet, Fabien; Durand, Gael

2016-04-01

The understanding of grounding line dynamics is a major issue in the prediction of future sea level rise due to ice released from polar ice sheets into the ocean. This dynamics is complex and significantly affected by several physical processes not always adequately accounted for in current ice flow models. Among those processes, our study focuses on ice damage and evolving basal friction conditions. Softening of the ice due to damaging processes is known to have a strong impact on its rheology by reducing its viscosity and therefore promoting flow acceleration. Damage creates where shear stresses are high enough which is usually the case at shear margins and in the vicinity of pinning points in contact with ice-shelves. Those areas are known to have a buttressing effect on ice shelves contributing to stabilize the grounding line. We aim at evaluating the extent to which this stabilizing effect is hampered by damaging processes. Several friction laws have been proposed by various author to model the contact between grounded-ice and bedrock. Among them, Coulomb-type friction laws enable to account for reduced friction related to low effective pressure (the ice pressure minus the water pressure). Combining such a friction law to a parametrization of the effective pressure accounting for the fact that the area upstream the grounded line is connected to the ocean, is expected to have a significant impact on the grounding line dynamics. Using the finite-element code Elmer/Ice within which both the Coulomb-type friction law, the effective pressure parametrization and the damage model have been implemented, the goal of this study is to investigate the sensitivity of the grounding line dynamics to damage and to an evolving basal friction. The relative importance between those two processes on the grounding line dynamics is addressed as well.

The role of non-ionizing radiation pressure in star formation: the stability of cores and filaments

NASA Astrophysics Data System (ADS)

Seo, Young Min; Youdin, Andrew N.

2016-09-01

Stars form when filaments and dense cores in molecular clouds fragment and collapse due to self-gravity. In the most basic analyses of gravitational stability, the competition between self-gravity and thermal pressure sets the critical (I.e. maximum stable) mass of spheres and the critical line density of cylinders. Previous work has considered additional support from magnetic fields and turbulence. Here, we consider the effects of non-ionizing radiation, specifically the inward radiation pressure force that acts on dense structures embedded in an isotropic radiation field. Using hydrostatic, isothermal models, we find that irradiation lowers the critical mass and line density for gravitational collapse, and can thus act as a trigger for star formation. For structures with moderate central densities, ˜103 cm-3, the interstellar radiation field in the Solar vicinity has an order unity effect on stability thresholds. For more evolved objects with higher central densities, a significant lowering of stability thresholds requires stronger irradiation, as can be found closer to the Galactic centre or near stellar associations. Even when strong sources of ionizing radiation are absent or extincted, our study shows that interstellar irradiation can significantly influence the star formation process.

On-line determination of transient stability status using multilayer perceptron neural network

NASA Astrophysics Data System (ADS)

Frimpong, Emmanuel Asuming; Okyere, Philip Yaw; Asumadu, Johnson

2018-01-01

A scheme to predict transient stability status following a disturbance is presented. The scheme is activated upon the tripping of a line or bus and operates as follows: Two samples of frequency deviation values at all generator buses are obtained. At each generator bus, the maximum frequency deviation within the two samples is extracted. A vector is then constructed from the extracted maximum frequency deviations. The Euclidean norm of the constructed vector is calculated and then fed as input to a trained multilayer perceptron neural network which predicts the stability status of the system. The scheme was tested using data generated from the New England test system. The scheme successfully predicted the stability status of all two hundred and five disturbance test cases.

Field-Line Localized Destabilization of Ballooning Modes in Three-Dimensional Tokamaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willensdorfer, M.; Cote, T. B.; Hegna, C. C.

2017-08-25

Field-line localized ballooning modes have been observed at the edge of high confinement mode plasmas in ASDEX Upgrade with rotating 3D perturbations induced by an externally applied n ¼ 2 error field and during a moderate level of edge localized mode mitigation. The observed ballooning modes are localized to the field lines which experience one of the two zero crossings of the radial flux surface displacement during one rotation period. The localization of the ballooning modes agrees very well with the localization of the largest growth rates from infinite-n ideal ballooning stability calculations using a realistic 3D ideal magnetohydrodynamic equilibrium.more » This analysis predicts a lower stability with respect to the axisymmetric case. The primary mechanism for the local lower stability is the 3D distortion of the local magnetic shear.« less

Engineering Lipases: walking the fine line between activity and stability

NASA Astrophysics Data System (ADS)

Dasetty, Siva; Blenner, Mark A.; Sarupria, Sapna

2017-11-01

Lipases are enzymes that hydrolyze lipids and have several industrial applications. There is a tremendous effort in engineering the activity, specificity and stability of lipases to render them functional in a variety of environmental conditions. In this review, we discuss the recent experimental and simulation studies focused on engineering lipases. Experimentally, mutagenesis studies have demonstrated that the activity, stability, and specificity of lipases can be modulated by mutations. It has been particularly challenging however, to elucidate the underlying mechanisms through which these mutations affect the lipase properties. We summarize results from experiments and molecular simulations highlighting the emerging picture to this end. We end the review with suggestions for future research which underscores the delicate balance of various facets in the lipase that affect their activity and stability necessitating the consideration of the enzyme as a network of interactions.

X-Ray Photoelectron Spectroscopy of Stabilized Zirconia Films with Embedded Au Nanoparticles Formed under Irradiation with Gold Ions

NASA Astrophysics Data System (ADS)

Zubkov, S. Yu.; Antonov, I. N.; Gorshkov, O. N.; Kasatkin, A. P.; Kryukov, R. N.; Nikolichev, D. E.; Pavlov, D. A.; Shenina, M. E.

2018-03-01

Nanosized films of stabilized zirconia with Au nanoparticles formed by implanting Au ions are studied by X-ray photoelectron spectroscopy and transmission electron microscopy. The effect of irradiation of films with Au ions and postimplantation annealing on the distribution of chemical elements and zirconium- containing ZrO x compounds over the depth of the films is studied. Based on the data on the dimensional shift of the Au 4 f photoelectron line, the average value of the nanoparticle size is determined.

Electric Propulsion Test and Evaluation Methodologies for Plasma in the Environments of Space and Testing (EP TEMPEST)

DTIC Science & Technology

2016-04-14

Swanson AEDC Path 1: Magnetized electron transport impeded across magnetic field lines; transport via electron-particle collisions Path 2*: Electron...T&E (higher pressure, metallic walls) → Impacts stability, performance, plume properties, thruster lifetime Magnetic Field Lines Plasma Plume...Development of T&E Methodologies • Current-Voltage- Magnetic Field (I-V-B) Mapping • Facility Interaction Studies • Background Pressure • Plasma Wall

Cell culture media impact on drug product solution stability.

PubMed

Purdie, Jennifer L; Kowle, Ronald L; Langland, Amie L; Patel, Chetan N; Ouyang, Anli; Olson, Donald J

2016-07-08

To enable subcutaneous administration of monoclonal antibodies, drug product solutions are often needed at high concentrations. A significant risk associated with high drug product concentrations is an increase in aggregate level over the shelf-life dating period. While much work has been done to understand the impact of drug product formulation on aggregation, there is limited understanding of the link between cell culture process conditions and soluble aggregate growth in drug product. During cell culture process development, soluble aggregates are often measured at harvest using cell-free material purified by Protein A chromatography. In the work reported here, cell culture media components were evaluated with respect to their impact on aggregate levels in high concentration solution drug product during accelerated stability studies. Two components, cysteine and ferric ammonium citrate, were found to impact aggregate growth rates in our current media (version 1) leading to the development of new chemically defined media and concentrated feed formulations. The new version of media and associated concentrated feeds (version 2) were evaluated across four cell lines producing recombinant IgG4 monoclonal antibodies and a bispecific antibody. In all four cell lines, the version 2 media reduced aggregate growth over the course of a 12 week accelerated stability study compared with the version 1 media, although the degree to which aggregate growth decreased was cell line dependent. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:998-1008, 2016. © 2016 American Institute of Chemical Engineers.

Antarctic grounding-line migration

NASA Astrophysics Data System (ADS)

Slater, T.; Konrad, H.; Shepherd, A.; Gilbert, L.; Hogg, A.; McMillan, M.; Muir, A. S.

2017-12-01

Knowledge of grounding-line position is critical for quantifying ice discharge into the ocean, as a boundary condition for numerical models of ice flow, and as an indicator of ice sheet stability. Although geological investigations have documented extensive grounding-line retreat since the period of the Last Glacial Maximum, observations of grounding line migration during the satellite era are restricted to a handful of locations. We combine satellite altimeter observations of ice-elevation change and airborne measurements of ice geometry to track movement of the Antarctic Ice Sheet grounding line. Based on these data, we estimate that 22%, 3%, and 10% of the West Antarctic, East Antarctic, and Antarctic Peninsula ice sheet grounding lines are retreating at rates faster than the typical pace since the Last Glacial Maximum, and that the continent loses over 200 km2 of grounded-ice area per year. Although by far the fastest rates of retreat occurred in the Amundsen Sea Sector, the Pine Island Glacier grounding line has stabilized - likely as a consequence of abated ocean forcing during the survey period.

Optical frequency stabilization in infrared region using improved dual feed-back loop

NASA Astrophysics Data System (ADS)

Ružička, B.; Číp, O.; Lazar, J.

2007-03-01

Modern technologies such as DWDM (Dense Wavelength Division Multiplex) need precise stability of laser frequencies. According to this fact, requirements of new etalons of optical frequencies in the telecommunication band is rapidly growing. Lasers working in near infrared telecommunication band (1500-1600 nm) can be stabilized to 12C IIH II or 13C IIH II (acetylene) gas absorption lines. The acetylene gas absorption has been widely studied and accepted by international bodies of standardization as a primary wavelength reference in the near infrared band around 1550 nm. Our aim was to design and develop a compact fibre optics laser system generating coherent light in near-IR band with high frequency stability (at least 1.10 -8). This system should become a base for realization of a primary frequency standard for optical communications in the Czech Republic. Such an etalon will be needed for calibration of wavelengthmeters and spectral analysers for DWDM communication systems. We are co-operating with CMI (Czech Metrology Institute) on this project. We present stabilized laser system based on a single frequency DFB (Distributed Feedback) laser diode with a narrow spectral profile. The laser is pre-stabilized by means of the FM-spectroscopy on a passive resonator. Thanks to a fast feed-back loop we are able to improve spectral characteristics of the laser. The laser frequency is locked by a relatively slow second feed-back loop on an absorption line of acetylene vapour which is sealed in a cell under the optimised pressure.

Puget Sound Area Electric Reliability Plan : Appendix E, Transmission Reinforcement Analysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

United States. Bonneville Power Administration.

1992-04-01

The purpose of this appendix to the draft environmental impact statement (EIS) report is to provide an update of the latest study work done on transmission system options for the Puget Sound Area Electric Reliability Plan. Also included in the attachments to the EIS are 2 reports analyzing the voltage stability of the Puget Sound transmission system and a review by Power Technologies, Inc. of the BPA voltage stability analysis and reactive options. Five transmission line options and several reactive options are presently being considered as possible solutions to the PSAFRP by the Transmission Team. The first two line optionsmore » would be built on new rights-of way adjacent (as much as possible) to existing corridors. The reactive options would optimize the existing transmission system capability by adding new stations for series capacitors and/or switchgear. The other three line options are rebuilds or upgrades of existing cross mountain transmission lines. These options are listed below and include a preliminary assessment of the additional transmission system reinforcement required to integrate the new facilities into the existing transmission system. Plans were designed to provide at least 500 MVAR reactive margin.« less

Computer Programs for Calculating and Plotting the Stability Characteristics of a Balloon Tethered in a Wind

NASA Technical Reports Server (NTRS)

Bennett, R. M.; Bland, S. R.; Redd, L. T.

1973-01-01

Computer programs for calculating the stability characteristics of a balloon tethered in a steady wind are presented. Equilibrium conditions, characteristic roots, and modal ratios are calculated for a range of discrete values of velocity for a fixed tether-line length. Separate programs are used: (1) to calculate longitudinal stability characteristics, (2) to calculate lateral stability characteristics, (3) to plot the characteristic roots versus velocity, (4) to plot the characteristic roots in root-locus form, (5) to plot the longitudinal modes of motion, and (6) to plot the lateral modes for motion. The basic equations, program listings, and the input and output data for sample cases are presented, with a brief discussion of the overall operation and limitations. The programs are based on a linearized, stability-derivative type of analysis, including balloon aerodynamics, apparent mass, buoyancy effects, and static forces which result from the tether line.

Propagation and stability characteristics of a 500-m-long laser-based fiducial line for high-precision alignment of long-distance linear accelerators.

PubMed

Suwada, Tsuyoshi; Satoh, Masanori; Telada, Souichi; Minoshima, Kaoru

2013-09-01

A laser-based alignment system with a He-Ne laser has been newly developed in order to precisely align accelerator units at the KEKB injector linac. The laser beam was first implemented as a 500-m-long fiducial straight line for alignment measurements. We experimentally investigated the propagation and stability characteristics of the laser beam passing through laser pipes in vacuum. The pointing stability at the last fiducial point was successfully obtained with the transverse displacements of ±40 μm level in one standard deviation by applying a feedback control. This pointing stability corresponds to an angle of ±0.08 μrad. This report contains a detailed description of the experimental investigation for the propagation and stability characteristics of the laser beam in the laser-based alignment system for long-distance linear accelerators.

How nanobubbles lose stability: Effects of surfactants

NASA Astrophysics Data System (ADS)

Xiao, Qianxiang; Liu, Yawei; Guo, Zhenjiang; Liu, Zhiping; Zhang, Xianren

2017-09-01

In contrast to stability theories of nanobubbles, the molecular mechanism of how nanobubbles lose stability is far from being understood. In this work, we try to interpret recent experimental observations that the addition of surfactants destabilizes nanobubbles with an unclear mechanism. Using molecular dynamics simulations, we identify two surfactant-induced molecular mechanisms for nanobubbles losing stability, either through depinning of a contact line or reducing vapor-liquid surface tension. One corresponds to the case with significant adsorption of surfactants on the substrates, which causes depinning of the nanobubble contact line and thus leads to nanobubble instability. The other stresses surfactant adsorption on the vapor-liquid interface of nanobubbles, especially for insoluble surfactants, which reduces the surface tension of the interface and leads to an irreversible liquid-to-vapor phase transition. Our finding can help improve our understanding in nanobubble stability, and the insight presented here has implications for surface nanobubbles involving with other amphiphilic molecules, such as proteins and contaminations.

Quadrupole mass filter: design and performance for operation in stability zone 3.

PubMed

Syed, Sarfaraz U A H; Hogan, Thomas J; Antony Joseph, Mariya J; Maher, Simon; Taylor, Stephen

2013-10-01

The predicted performance of a quadrupole mass filter (QMF) operating in Mathieu stability zone 3 is described in detail using computer simulations. The investigation considers the factors that limit the ultimate maximum resolution (Rmax) and percentage transmission (%Tx), which can be obtained for a given QMF for a particular scan line of operation. The performance curve (i.e., the resolution (R) versus number (N) of radio frequency (rf) cycles experienced by the ions in the mass filter) has been modeled for the upper and lower tip of stability zone 3. The saturation behavior of the performance curve observed in practice for zone 3 is explained. Furthermore, new design equations are presented by examining the intersection of the scan line with stability zone 3. Resolution versus transmission characteristics of stability zones 1 and 3 are compared and the dependence of performance for zones 1 and 3 is related to particular instrument operating parameters.

Propagation and stability characteristics of a 500-m-long laser-based fiducial line for high-precision alignment of long-distance linear accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suwada, Tsuyoshi; Satoh, Masanori; Telada, Souichi

2013-09-15

A laser-based alignment system with a He-Ne laser has been newly developed in order to precisely align accelerator units at the KEKB injector linac. The laser beam was first implemented as a 500-m-long fiducial straight line for alignment measurements. We experimentally investigated the propagation and stability characteristics of the laser beam passing through laser pipes in vacuum. The pointing stability at the last fiducial point was successfully obtained with the transverse displacements of ±40 μm level in one standard deviation by applying a feedback control. This pointing stability corresponds to an angle of ±0.08 μrad. This report contains a detailedmore » description of the experimental investigation for the propagation and stability characteristics of the laser beam in the laser-based alignment system for long-distance linear accelerators.« less

Ice-proximal sediment dynamics and their effect on the stability of Muir Glacier, Alaska: A case study of non-climatic glacier response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunter, L.E.; Powell, R.D.

1992-01-01

Recent studies have shown that water depth at tidewater termini affect calving rates and, therefore, glacier mass balance and terminus stability. Grounding-line water depths are themselves governed by glacial and marine processes that interact during the formation of morainal bank depocenters. These morainal banks can fluctuate 10s of meters in height within an interval of a few weeks. Recent investigations in Glacier Bay have focused on quantitatively assessing sediment budgets in the ice-proximal environment. The monitoring of morainal banks in upper Muir Inlet has included repeated bathymetric mapping, sediment trap studies, bottom grab sampling, glacier and iceberg sampling, and submersiblemore » ROV investigations within 1 km of the terminus. Such relationships are important in interpreting recent changes in the dynamics of Muir Glacier where a century of retreat has been succeeded by quasi stability. The new glacier regime has accompanied basin infilling from approximately 100 m depth to a maximum of 52 m at the grounding line. Two large grounding-line fans have aggraded to deltas and reduced the length of the calving margin from 900 m to 290 m wide. These effects have reduced the ice flow velocities by 45%. Annual morainal bank growth ranged from 10[sup 6] to 10[sup 7] m[sup 3] and is the result of glacifluvial dumping, suspension settling from turbid overflow plumes, debris dumping from ice-cliff and iceberg melting, glacier squeezing and pushing of morainal bank sediment, and sediment gravity flow processes. Each of these processes are an integral facet of the morainal bank dynamics and glacier response. These studies of Muir Glacier indicate that glacier response to sediment dynamics need to be addresses before climatic implications are made.« less

Careful Selection of Reference Genes Is Required for Reliable Performance of RT-qPCR in Human Normal and Cancer Cell Lines

PubMed Central

Jacob, Francis; Guertler, Rea; Naim, Stephanie; Nixdorf, Sheri; Fedier, André; Hacker, Neville F.; Heinzelmann-Schwarz, Viola

2013-01-01

Reverse Transcription - quantitative Polymerase Chain Reaction (RT-qPCR) is a standard technique in most laboratories. The selection of reference genes is essential for data normalization and the selection of suitable reference genes remains critical. Our aim was to 1) review the literature since implementation of the MIQE guidelines in order to identify the degree of acceptance; 2) compare various algorithms in their expression stability; 3) identify a set of suitable and most reliable reference genes for a variety of human cancer cell lines. A PubMed database review was performed and publications since 2009 were selected. Twelve putative reference genes were profiled in normal and various cancer cell lines (n = 25) using 2-step RT-qPCR. Investigated reference genes were ranked according to their expression stability by five algorithms (geNorm, Normfinder, BestKeeper, comparative ΔCt, and RefFinder). Our review revealed 37 publications, with two thirds patient samples and one third cell lines. qPCR efficiency was given in 68.4% of all publications, but only 28.9% of all studies provided RNA/cDNA amount and standard curves. GeNorm and Normfinder algorithms were used in 60.5% in combination. In our selection of 25 cancer cell lines, we identified HSPCB, RRN18S, and RPS13 as the most stable expressed reference genes. In the subset of ovarian cancer cell lines, the reference genes were PPIA, RPS13 and SDHA, clearly demonstrating the necessity to select genes depending on the research focus. Moreover, a cohort of at least three suitable reference genes needs to be established in advance to the experiments, according to the guidelines. For establishing a set of reference genes for gene normalization we recommend the use of ideally three reference genes selected by at least three stability algorithms. The unfortunate lack of compliance to the MIQE guidelines reflects that these need to be further established in the research community. PMID:23554992

The availability of diltiazem: a study on the sorption by intravenous delivery systems and on the stability of the drug.

PubMed

De Vroe, C; De Muynck, C; Remon, J P; Scheldewaert, R; Colardyn, F

1989-04-01

The stability and the sorption by intravenous delivery systems of the calcium antagonist diltiazem dissolved into either 5% dextrose or 0.9% sodium chloride solutions have been investigated, under conditions simulating current clinical practice. Static experiments showed an excellent stability and no sorption after 48 h. Dynamic experiments, at a perfusion rate of 20 mg h-1, showed no sorption of the drug by infusion fluid containers, burettes or administration sets. For end-line filters a temporary decrease of the recovered amount of diltiazem was observed but only with the 0.9% NaCl solution. It is concluded that the stability and the sorption of diltiazem offers no problem with regard to clinical efficacy.

Candidate Reference Genes Selection and Application for RT-qPCR Analysis in Kenaf with Cytoplasmic Male Sterility Background

PubMed Central

Zhou, Bujin; Chen, Peng; Khan, Aziz; Zhao, Yanhong; Chen, Lihong; Liu, Dongmei; Liao, Xiaofang; Kong, Xiangjun; Zhou, Ruiyang

2017-01-01

Cytoplasmic male sterility (CMS) is a maternally inherited trait that results in the production of dysfunctional pollen. Based on reliable reference gene-normalized real-time quantitative PCR (RT-qPCR) data, examining gene expression profile can provide valuable information on the molecular mechanism of kenaf CMS. However, studies have not been conducted regarding selection of reference genes for normalizing RT-qPCR data in the CMS and maintainer lines of kenaf crop. Therefore, we studied 10 candidate reference genes (ACT3, ELF1A, G6PD, PEPKR1, TUB, TUA, CYP, GAPDH, H3, and 18S) to assess their expression stability at three stages of pollen development in CMS line 722A and maintainer line 722B of kenaf. Five computational statistical approaches (GeNorm, NormFinder, ΔCt, BestKeeper, and RefFinder) were used to evaluate the expression stability levels of these genes. According to RefFinder and GeNorm, the combination of TUB, CYP, and PEPKR1 was identified as an internal control for the accurate normalization across all sample set, which was further confirmed by validating the expression of HcPDIL5-2a. Furthermore, the combination of TUB, CYP, and PEPKR1 was used to differentiate the expression pattern of five mitochondria F1F0-ATPase subunit genes (atp1, atp4, atp6, atp8, and atp9) by RT-qPCR during pollen development in CMS line 722A and maintainer line 722B. We found that atp1, atp6, and atp9 exhibited significantly different expression patterns during pollen development in line 722A compared with line 722B. This is the first systematic study of reference genes selection for CMS and will provide useful information for future research on the gene expressions and molecular mechanisms underlying CMS in kenaf. PMID:28919905

A comparison study of nanofiber, microfiber, and new composite nano/microfiber polymers used as sorbents for on-line solid phase extraction in chromatography system.

PubMed

Háková, Martina; Havlíková, Lucie Chocholoušová; Chvojka, Jiří; Erben, Jakub; Solich, Petr; Švec, František; Šatínský, Dalibor

2018-09-06

Three different approaches has been used to obtain nano/micro fibers and their diversity and extraction properties were examined. The effect of their structure on stability in an ultra-high-performance liquid chromatography (UHPLC) system during on-line SPE procedure was monitored. Five types of various nano/micro fiber polymers were used as sorbents: polyamide 6 nanofibers, polyvinylidene difluoride nanofibers, polyethylene microfibers, and two new polycaprolactone microfiber/nanofiber and polycaprolactone microfibers/polyvinylidene difluoride nanofibers composite polymers. The fiber polymers were filled in a cartridge directly connected to the UHPLC system and tested. For each polymer, the optimal conditions of the on-line extraction were found and potential applicability on real samples was tested. The determination of ochratoxin A (OTA) in beer matrix was chosen as a case study. Relevant factors such as the mechanical and chemical stability of the nano/microfibers, filling the cartridges, fiber reusability and the possibility and the repeatability of all processes were involved in the proposed study. A new nano/micro composite sorbent consisting of polycaprolactone microfibers/polyvinylidene difluoride nanofibers was chosen as the most suitable sorbent for the on-line extraction of OTA from a beer matrix. The tested validation parameters had the value of intra-day precision lower than 1.48%, linearity in the range from 0.5 to 100 μg L -1 with r 2  ≥ 0.9999 for standard and matrix calibration curve, and recovery in the range 99.1-103.9% at five concentration levels. Long-term precision evaluated for 31 analyses over the period of three months did not exceed 2.9% RSD. It confirmed the column reusability and perfect stability of nano/micro composite sorbent in the presence of organic solvents and after repeated injection of a complex beer matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

Flow Range of Centrifugal Compressor Being Extended

NASA Technical Reports Server (NTRS)

Skoch, Gary J.

2001-01-01

General Aviation will benefit from turbine engines that are both fuel-efficient and reliable. Current engines fall short of their potential to achieve these attributes. The reason is compressor surge, which is a flow stability problem that develops when the compressor is subjected to conditions that are outside of its operating range. Compressor surge can occur when fuel flow to the engine is increased, temporarily back pressuring the compressor and pushing it past its stability limit, or when the compressor is subjected to inlet flow-field distortions that may occur during takeoff and landing. Compressor surge can result in the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. Unfortunately, the most efficient operating line for the compressor is usually closer to its stability limit line than it is to the line that provides an adequate margin of safety. A wider stable flow range will permit operation along the most efficient operating line of the compressor, improving the specific fuel consumption of the engine and reducing emissions. The NASA Glenn Research Center is working to extend the stable flow range of the compressor. Significant extension has been achieved in axial compressors by injecting air upstream of the compressor blade rows. Recently, the technique was successfully applied to a 4:1 pressure ratio centrifugal compressor by injecting streams of air into the diffuser. Both steady and controlled unsteady injection were used to inject air through the diffuser shroud surface and extend the range. Future work will evaluate the effect of air injection through the diffuser hub surface and diffuser vanes with the goal of maximizing the range extension while minimizing the amount of injected air that is required.

An extended continuum model accounting for the driver's timid and aggressive attributions

NASA Astrophysics Data System (ADS)

Cheng, Rongjun; Ge, Hongxia; Wang, Jufeng

2017-04-01

Considering the driver's timid and aggressive behaviors simultaneously, a new continuum model is put forwarded in this paper. By applying the linear stability theory, we presented the analysis of new model's linear stability. Through nonlinear analysis, the KdV-Burgers equation is derived to describe density wave near the neutral stability line. Numerical results verify that aggressive driving is better than timid act because the aggressive driver will adjust his speed timely according to the leading car's speed. The key improvement of this new model is that the timid driving deteriorates traffic stability while the aggressive driving will enhance traffic stability. The relationship of energy consumption between the aggressive and timid driving is also studied. Numerical results show that aggressive driver behavior can not only suppress the traffic congestion but also reduce the energy consumption.

The Freedmen’s Bureau, Politics, and Stability Operations during Reconstruction in the South

DTIC Science & Technology

2009-06-12

Movement in the 1960s. 15. SUBJECT TERMS Freedmen‘s Bureau, Stability Operations, Andrew Johnson, Reconstruction 16. SECURITY CLASSIFICATION OF...Mercer Langston (1829-1897) [on-line]; available from http://www. oberlin.edu /external/ EOG /OYTT-images/JMLangston.html; Internet; accessed 26 March...by sentiment more in line with the South‘s old ruling class view of labor, society, and governance. 53 Democratic victories of 1874 signaled a

The Stable Solar Analyzer

NASA Technical Reports Server (NTRS)

Rust, D. M.; Appourchaux, T.

1988-01-01

Progress in the development of an instrument with very high (1:10 billion) wavelength stability designed to measure solar surface velocities and magnetic fields is reported. The instrument determines Doppler and Zeeman shifts in solar spectral lines by a 6-point weighted average. It is built around an electrically tunable solid lithium-niobate Fabry-Perot etalon that is stabilized against a diode laser which itself is locked to a resonance line of cesium 133. Key features are the etalon, which acts as a wide-angle 0.017-nm solar filter, the camera with a specially stabilized shutter, and the instrument control and data collection system. Use of the instrument in helioseismological research is emphasized.

Utilizing Flight Data to Update Aeroelastic Stability Estimates

NASA Technical Reports Server (NTRS)

Lind, Rick; Brenner, Marty

1997-01-01

Stability analysis of high performance aircraft must account for errors in the system model. A method for computing flutter margins that incorporates flight data has been developed using robust stability theory. This paper considers applying this method to update flutter margins during a post-flight or on-line analysis. Areas of modeling uncertainty that arise when using flight data with this method are investigated. The amount of conservatism in the resulting flutter margins depends on the flight data sets used to update the model. Post-flight updates of flutter margins for an F/A-18 are presented along with a simulation of on-line updates during a flight test.

The transcriptional diversity of 25 Drosophila cell lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cherbas, Lucy; Willingham, Aarron; Zhang, Dayu

2010-12-22

Drosophila melanogaster cell lines are important resources for cell biologists. In this article, we catalog the expression of exons, genes, and unannotated transcriptional signals for 25 lines. Unannotated transcription is substantial (typically 19% of euchromatic signal). Conservatively, we identify 1405 novel transcribed regions; 684 of these appear to be new exons of neighboring, often distant, genes. Sixty-four percent of genes are expressed detectably in at least one line, but only 21% are detected in all lines. Each cell line expresses, on average, 5885 genes, including a common set of 3109. Expression levels vary over several orders of magnitude. Major signalingmore » pathways are well represented: most differentiation pathways are ‘‘off’’ and survival/growth pathways ‘‘on.’’ Roughly 50% of the genes expressed by each line are not part of the common set, and these show considerable individuality. Thirty-one percent are expressed at a higher level in at least one cell line than in any single developmental stage, suggesting that each line is enriched for genes characteristic of small sets of cells. Most remarkable is that imaginal disc-derived lines can generally be assigned, on the basis of expression, to small territories within developing discs. These mappings reveal unexpected stability of even fine-grained spatial determination. No two cell lines show identical transcription factor expression. We conclude that each line has retained features of an individual founder cell superimposed on a common ‘‘cell line‘‘ gene expression pattern. We report the transcriptional profiles of 25 Drosophila melanogaster cell lines, principally by whole-genome tiling microarray analysis of total RNA, carried out as part of the modENCODE project. The data produced in this study add to our knowledge of the cell lines and of the Drosophila transcriptome in several ways. We summarize the expression of previously annotated genes in each of the 25 lines with emphasis on what those patterns reveal about the origins of the lines and the stability of spatial expression patterns. In addition, we offer an initial analysis of previously unannotated transcripts in the cell lines.« less

Determination of pore-scale hydrate phase equilibria in sediments using lab-on-a-chip technology.

PubMed

Almenningen, Stian; Flatlandsmo, Josef; Kovscek, Anthony R; Ersland, Geir; Fernø, Martin A

2017-11-21

We present an experimental protocol for fast determination of hydrate stability in porous media for a range of pressure and temperature (P, T) conditions. Using a lab-on-a-chip approach, we gain direct optical access to dynamic pore-scale hydrate formation and dissociation events to study the hydrate phase equilibria in sediments. Optical pore-scale observations of phase behavior reproduce the theoretical hydrate stability line with methane gas and distilled water, and demonstrate the accuracy of the new method. The procedure is applicable for any kind of hydrate transitions in sediments, and may be used to map gas hydrate stability zones in nature.

Line tension effects on the wetting of nanostructures: an energy method

NASA Astrophysics Data System (ADS)

Guo, Hao-Yuan; Li, Bo; Feng, Xi-Qiao

2017-09-01

The superhydrophobicity and self-cleaning property of micro/nano-structured solid surfaces require a stable Cassie-Baxter (CB) wetting state at the liquid-solid interface. We present an energy method to investigate how the three-phase line tension affects the CB wetting state on nanostructured materials. For some nanostructures, the line tension may engender a distinct energy barrier, which restricts the position of the three-phase contact line and affects the stability of the CB wetting state. We ascertain the upper and lower limits of the critical pressure at the CB-Wenzel transition. Our results suggest that superhydrophobicity on nanostructures can be modulated by tailoring the line tension and harnessing the curvature effect. This study also provides new insights into the sinking phenomena observed in the nanoparticle-floating experiment.

Stabilizing detached Bridgman melt crystal growth: Proportional-integral feedback control

NASA Astrophysics Data System (ADS)

Yeckel, Andrew; Daoutidis, Prodromos; Derby, Jeffrey J.

2012-10-01

The dynamics, operability limits, and tuning of a proportional-integral feedback controller to stabilize detached vertical Bridgman crystal growth are analyzed using a capillary model of shape stability. The manipulated variable is the pressure difference between upper and lower vapor spaces, and the controlled variable is the gap width at the triple-phase line. Open and closed loop dynamics of step changes in these state variables are analyzed under both shape stable and shape unstable growth conditions. Effects of step changes in static contact angle and growth angle are also studied. Proportional and proportional-integral control can stabilize unstable growth, but only within tight operability limits imposed by the narrow range of allowed meniscus shapes. These limits are used to establish safe operating ranges of controller gain. Strong nonlinearity of the capillary model restricts the range of perturbations that can be stabilized, and under some circumstances, stabilizes a spurious operating state far from the set point. Stabilizing detachment at low growth angle proves difficult and becomes impossible at zero growth angle.

The effects of viscosity on the stability of a trailing-line vortex in compressible flow

NASA Technical Reports Server (NTRS)

Stott, Jillian A. K.; Duck, Peter W.

1994-01-01

We consider the effects of viscosity on the inviscid stability of the Batchelor vortex in a compressible flow. The problem is tackled asymptotically, in the limit of large (streamwise and azimuthal) wavenumbers, together with large Mach numbers. Previous studies, with viscous effects neglected, found that the nature of the solution passes through different regimes as the Mach number increases, relative to the wavenumber. This structure persists when viscous effects are included in the analysis. In the present study the mode present in the incompressible case ceases to be unstable at high Mach numbers and a center mode forms, whose stability characteristics are determined primarily by conditions close to the vortex axis. We find generally that viscosity has a stabilizing influence on the flow, while in the case of center modes, viscous effects become important at much larger Reynolds numbers than for the first class of disturbance.

On the effects of viscosity on the stability of a trailing-line vortex

NASA Technical Reports Server (NTRS)

Duck, Peter W.; Khorrami, Mehdi R.

1991-01-01

The linear stability of the Batchelor (1964) vortex is investigated. Particular emphasis is placed on modes found recently in a numerical study by Khorrami (1991). These modes have a number of features very distinct from those found previously for this vortex, including exhibiting small growth rates at large Reynolds numbers and susceptibility to destabilization by viscosity. These modes are described using asymptotic techniques, producing results which compare favorably with fully numerical results at large Reynolds numbers.

Study of Running Stability in Side-Suspended HTS-PMG Maglev Circular Line System

NASA Astrophysics Data System (ADS)

Zhou, Dajin; Zhao, Lifeng; Li, Linbo; Cui, Chenyu; Hsieh, Chang-Chun; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

2017-07-01

A research on stability of the side-suspended HTS-PMG maglev circular line system is carried out through simulation experiment. The results show that the maglev vehicle will gradually get close to the track surface during acceleration under the action of centrifugal force, leading to decay of guidance force and occurrence of vertical eccentric motion. In case of linear array of YBa2Cu3O7-x (YBCO) bulks, the guidance force will be changed with the decreasing of the levitation gap. It can be suppressed through the complex arrangement of YBCO bulks. Fortunately, triangle array of YBCO bulks can effectively keep the guidance force constant and realize stable running during accelerating process of the prototype vehicle. Based on the research on stability of side-suspended maglev vehicle, a side-suspended PMG circular test track with diameter of 6.5 m and circumference of 20.4 m is successfully designed and established, enabling the prototype vehicle to run stably at up to 82.5 km/h under open atmosphere (9.6 × 104 Pa).

Evaluation of TBM tunnels with respect to stability against spalling

NASA Astrophysics Data System (ADS)

Shaalan, Heyam; Ismail, Mohd Ashraf Mohd; Azit, Romziah

2017-10-01

As the depth of tunnels and underground construction increases, instability occurs in the form of rock bursting or spalling because of the induced stresses. Spalling may appear as a strong compressive stress causing crack growth behind the excavated surface and buckling of the thin rock slabs. In this paper, we describe how to reduce the rock spalling failure to increase the underground safety and the tunnel stability. Thus, a parametric study is implemented using 2-D Elasto-plastic finite elements stress analysis software to investigate the parameters that can minimize the extent and depth of the failure zone. The critical section of Pahang Selangor Raw Water Transfer Tunnel under high overburden is analyzed. The effect of the shotcrete lining thickness, tunnel size and the removal of fallouts or scaled v-notch on the failure zone depth is investigated. The results demonstrate that the shotcrete lining thickness has less influence on the failure depth, while a small tunnel diameter minimizes the failure depth. In addition, the stability of the tunnel improves by removing the loose rock mass.

Supercritical fluid extraction (SFE) of ketamine metabolites from dried urine and on-line quantification by supercritical fluid chromatography and single mass detection (on-line SFE-SFC-MS).

PubMed

Hofstetter, Robert; Fassauer, Georg M; Link, Andreas

2018-02-15

On-line solid-phase supercritical fluid extraction (SFE) and chromatography (SFC) coupled to mass spectrometry (MS) has been evaluated for its usefulness with respect to metabolic profiling and pharmacological investigations of ketamine in humans. The aim of this study was to develop and validate a rapid, highly selective and sensitive SFE-SFC-MS method for the quantification of ketamine and its metabolites in miniature amounts in human urine excluding liquid-liquid extraction (LLE). Several conditions were optimized systematically following the requirements of the European Medicines Agency: selectivity, carry-over, calibration curve parameters (LLOQ, range and linearity), within- and between-run accuracy and precision, dilution integrity, matrix effect, and stability. The method, which required a relatively small volume of human urine (20 μL per sample), was validated for pharmacologically and toxicologically relevant concentrations ranging from 25.0 to 1000 ng/mL (r 2  > 0.995). The lower limit of quantification (LLOQ) for all compounds was found to be as low as 0.5 ng. In addition, stability of analytes during removal of water from the urine samples using different conditions (filter paper or ISOLUTE® HM-N) was studied. In conclusion, the method developed in this study can be successfully applied to studies of ketamine metabolites in humans, and may pave the way for routine application of on-line SFE-SFC-MS in clinical investigations. Copyright © 2018 Elsevier B.V. All rights reserved.

Coupled Directional Stability of Multiple Ship Formations

DTIC Science & Technology

2013-06-01

Papoulias, “Bifurcation analysis of line of sight vehicle guidance using sliding modes ,” Int. J. of Bifurcation and Chaos, vol. 1, p.4, 1991. [12] F...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) This thesis addresses the problem of coordinated motion control and the stability loss of surface...plane with no side slip. A state feedback control law is coupled with a line of sight guidance law to provide path control . A string of three vehicles

Lateral-directional stability characteristics of a wing-fuselage configuration at angles of attack up to 44 deg

NASA Technical Reports Server (NTRS)

Henderson, W. P.; Huffman, J. K.

1974-01-01

An investigation has been conducted to determine the effects of configuration variables on the lateral-directional stability characteristics of a wing-fuselage configuration. The variables under study included variations in the location of a single center-line vertical tail and twin vertical tails, wing height, fuselage strakes, and horizontal tails. The study was conducted in the Langley high-speed 7-by 10-foot tunnel at a Mach number of 0.30, at angles of attack up to 44 deg and at sideslip angles of 0 deg and plus or minus 5 deg.

Completely optical orientation determination for an unstabilized aerial three-line camera

NASA Astrophysics Data System (ADS)

Wohlfeil, Jürgen

2010-10-01

Aerial line cameras allow the fast acquisition of high-resolution images at low costs. Unfortunately the measurement of the camera's orientation with the necessary rate and precision is related with large effort, unless extensive camera stabilization is used. But also stabilization implicates high costs, weight, and power consumption. This contribution shows that it is possible to completely derive the absolute exterior orientation of an unstabilized line camera from its images and global position measurements. The presented approach is based on previous work on the determination of the relative orientation of subsequent lines using optical information from the remote sensing system. The relative orientation is used to pre-correct the line images, in which homologous points can reliably be determined using the SURF operator. Together with the position measurements these points are used to determine the absolute orientation from the relative orientations via bundle adjustment of a block of overlapping line images. The approach was tested at a flight with the DLR's RGB three-line camera MFC. To evaluate the precision of the resulting orientation the measurements of a high-end navigation system and ground control points are used.

Fabrication of amorphous curcumin nanosuspensions using β-lactoglobulin to enhance solubility, stability, and bioavailability.

PubMed

Aditya, N P; Yang, Hanjoo; Kim, Saehoon; Ko, Sanghoon

2015-03-01

Curcumin has low aqueous stability and solubility in its native form. It also has a low bioavailability which presents a major barrier to its use in fortifying food products. The aim of this work was to reduce the size of curcumin crystals to the nanoscale and subsequently stabilize them in an amorphous form. To this end, amorphous curcumin nanosuspensions were fabricated using the antisolvent precipitation method with β-lactoglobulin (β-lg) as a stabilizer. The resulting amorphous curcumin nanosuspensions were in the size range of 150-175 nm with unimodal size distribution. The curcumin particles were amorphous and were molecularly dispersed within the β-lg as confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. The solubility of the amorphous curcumin nanosuspension was enhanced ∼35-fold due to the reduced size and lower crystallinity. Among the formulations, the amorphous curcumin nanosuspensions stabilized with β-lg and prepared at pH 3.4 (β-lg-cur 3.4), showed maximum aqueous stability which was >90% after 30 days. An in vitro study using Caco-2 cell lines showed a significant increase in curcumin bioavailability after stabilization with β-lg. Copyright © 2015 Elsevier B.V. All rights reserved.

More than a safety line: jump-stabilizing silk of salticids.

PubMed

Chen, Yung-Kang; Liao, Chen-Pan; Tsai, Feng-Yueh; Chi, Kai-Jung

2013-10-06

Salticids are diurnal hunters known for acute vision, remarkable predatory strategies and jumping ability. Like other jumpers, they strive for stability and smooth landings. Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, we show that salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line. Analyses from high-speed images of jumps by the salticid Hasarius adansoni demonstrate that despite being subject to rearward pitch at take-off, spiders with dragline silk can change body orientation in the air. Instantaneous drag and silk forces calculated from kinematic data further suggest a comparable contribution to deceleration and energy dissipation, and reveal that adjustments by the spider to the silk force can reverse its body pitch for a predictable and optimal landing. Without silk, upright-landing spiders would slip or even tumble, deferring completion of landing. Thus, for salticids, dragline silk is critical for dynamic stability and prey-capture efficiency. The dynamic functioning of dragline silk revealed in this study can advance the understanding of silk's physiological control over material properties and its significance to spider ecology and evolution, and also provide inspiration for future manoeuvrable robot designs.

More than a safety line: jump-stabilizing silk of salticids

PubMed Central

Chen, Yung-Kang; Liao, Chen-Pan; Tsai, Feng-Yueh; Chi, Kai-Jung

2013-01-01

Salticids are diurnal hunters known for acute vision, remarkable predatory strategies and jumping ability. Like other jumpers, they strive for stability and smooth landings. Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, we show that salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line. Analyses from high-speed images of jumps by the salticid Hasarius adansoni demonstrate that despite being subject to rearward pitch at take-off, spiders with dragline silk can change body orientation in the air. Instantaneous drag and silk forces calculated from kinematic data further suggest a comparable contribution to deceleration and energy dissipation, and reveal that adjustments by the spider to the silk force can reverse its body pitch for a predictable and optimal landing. Without silk, upright-landing spiders would slip or even tumble, deferring completion of landing. Thus, for salticids, dragline silk is critical for dynamic stability and prey-capture efficiency. The dynamic functioning of dragline silk revealed in this study can advance the understanding of silk's physiological control over material properties and its significance to spider ecology and evolution, and also provide inspiration for future manoeuvrable robot designs. PMID:23925983

Flame Stabilization on Microscopic Scale of Wet Biogas with Microflame

NASA Astrophysics Data System (ADS)

Ida, Tamio; Fuchihata, Manabu; Mizuno, Satoru

Harvesting, transportation, energy conversion and the high-efficient utilization, cascade method and market formation besides become with the indispensable element in order to utilize the biomass resource. There are two type biogases; it is gasified gas from dried biomass by partially combustion and wet biogas from wet biomass by methane fermentation, especially from the livestock excrement resources. This paper discusses an experimental study for flame stabilization on microscopic scale with wet biogas (mainly 0.6CH4+0.4CO2). In this study, the microflame with the wet biogas fuels are formed by the diffusion flame on the coppered straight pipes of inner diameter 0.02mm ˜ 1.5mm. This study is obtained stability mapping on microscopic scale of formed microflame by wet biogas fuels. The flame stability limit conditions on microscopic scale of wet biogas is drawn with blow off and extinction flame double limit lines. It is suggested that minimum mixing spatial scale change by the each mixing ratio of the wet biogas.

Thermal bubble inkjet printing of water-based graphene oxide and graphene inks on heated substrate

NASA Astrophysics Data System (ADS)

Huang, Simin; Shen, Ruoxi; Qian, Bo; Li, Lingying; Wang, Wenhao; Lin, Guanghui; Zhang, Xiaofei; Li, Peng; Xie, Yonglin

2018-04-01

Stable-jetting water-based graphene oxide (GO) and graphene (GR) inks without any surfactant or stabilizer are prepared from an unstable-jetting water-based starting solvent, with many thermal bubble inkjet satellite drops, by simply increasing the material concentration. The concentration-dependent thermal bubble inkjet droplet generation process is studied in detail. To overcome the low concentration properties of water-based thermal bubble inkjet inks, the substrate temperature is tuned below 60 °C to achieve high-quality print lines. Due to the difference in hydrophilicity and hydrophobicity of the 2D materials, the printed GO lines show a different forming mechanism from that of the GR lines. The printed GO lines are reduced by thermal annealing and by ascorbic acid, respectively. The reduced GO lines exhibit electrical conductivity of the same order of magnitude as that of the GR lines.

Loran-C Signal Stability Study. Northeast and Southeast U.S

DTIC Science & Technology

1983-08-01

station would solve the problems along the Texas coast. The report shows that the repeatable accuracy of existing Loran-C Is better than 40-mpte--. 2...receivers are located at "unmanned" sites with the readings being sent to chain control stations (e.g., Seneca, Middletown) via phone lines. Thus...for a type A installation, we simply install equipment at the control station to "listen in" on the existing phone line and gather and store the data to

Factors influencing the QMF resolution for operation in stability zones 1 and 3.

PubMed

Syed, Sarfaraz U A H; Hogan, Thomas; Gibson, John; Taylor, Stephen

2012-05-01

This study uses a computer model to simulate a quadrupole mass filter (QMF) instrument under different operating conditions for Mathieu stability zones 1 and 3. The investigation considers the factors that limit the maximum resolution (R(max)), which can be obtained for a given QMF for a particular value of scan line. Previously, QMF resolution (R) has been found to be dependent on number (N) of radio frequency (rf) cycles experienced by the ions in the mass filter, according to R = N(n)/K, where n and K are the constants. However, this expression does not predict the limit to QMF resolution observed in practice and is true only for the linear regions of the performance curve for QMF operation in zone 1 and zone 3 of the stability diagram. Here we model the saturated regions of the performance curve for QMF operation in zone 1 according to R = q(1 - 2c(N))/∆q, where c is a constant and ∆q is the width of the intersection of the operating scan line with the stability zone 1, measured at q-axis of the Mathieu stability diagram. Also by careful calculations of the detail of the stability tip of zone 1, the following relationship was established between R(max) and percentage U/V ratio: R(max) = q/(0.9330-0.00933U/V). For QMF operation in zone 3 the expression R = a - bc(N) simulates well the linear and saturated regions of the performance curve for a range of operational conditions, where a, b, and c are constants.

Near-IR laser frequency standard stabilized using FM-spectroscopy

NASA Astrophysics Data System (ADS)

Ružička, Bohdan; Číp, Ondřej; Lazar, Josef

2006-02-01

At the present time fiber-optics and optical communication are in rapid progress. Modern technologies such as DWDM (Dense Wavelength Division Multiplex) need precise stability of laser frequencies. According to this fact, requirements of new etalons of optical frequencies in the telecommunication band is rapidly growing. Lasers working in near infrared telecommunication band (1500-1600 nm) can be stabilized to 12C IIH II or 13C IIH II (acetylene) gas absorption lines. The acetylene gas absorption has been widely studied and accepted by international bodies of standardization as a primary wavelength reference in the near infrared band around 1550nm. Our aim was to design and develop a compact fibre optics laser system generating coherent light in near-JR band with high frequency stability (at least 1.10 -8). This system should become a base for realization of a primary frequency standard for optical communications in the Czech Republic. Such an etalon will be needed for calibration of wavelength-meters and spectral analysers for DWDM communication systems. We are co-operating with CMI (Czech Metrology Institute) on this project. We present stabilized laser system based on a single frequency DFB (Distributed Feedback) laser diode with a narrow spectral profile. The laser is pre-stabilized by means of the FM-spectroscopy on a passive resonator. Thanks to a fast feed-back loop we are able to improve spectral characteristics of the laser. The laser frequency is locked by a relatively slow second feed-back loop on an absorption line of acetylene vapour which is sealed in a cell under the optimised pressure.

Stability Metrics for Simulation and Flight-Software Assessment and Monitoring of Adaptive Control Assist Compensators

NASA Technical Reports Server (NTRS)

Hodel, A. S.; Whorton, Mark; Zhu, J. Jim

2008-01-01

Due to a need for improved reliability and performance in aerospace systems, there is increased interest in the use of adaptive control or other nonlinear, time-varying control designs in aerospace vehicles. While such techniques are built on Lyapunov stability theory, they lack an accompanying set of metrics for the assessment of stability margins such as the classical gain and phase margins used in linear time-invariant systems. Such metrics must both be physically meaningful and permit the user to draw conclusions in a straightforward fashion. We present in this paper a roadmap to the development of metrics appropriate to nonlinear, time-varying systems. We also present two case studies in which frozen-time gain and phase margins incorrectly predict stability or instability. We then present a multi-resolution analysis approach that permits on-line real-time stability assessment of nonlinear systems.

Functionality of gliadin proteins in wheat flour tortillas.

PubMed

Mondal, Suchismita; Hays, Dirk B; Alviola, Noviola J; Mason, Richard E; Tilley, Michael; Waniska, Ralph D; Bean, Scott R; Glover, Karl D

2009-02-25

Gliadins are monomeric proteins that are encoded by the genes at the loci Gli 1 and Gli 2 present on the short arm of homologous wheat chromosomes 1 and 6, respectively. Studies have suggested that gliadins may play an important role in determining the functional properties of wheat flour. The main objective of this study was to understand the functionality of gliadins with respect to tortilla quality. The important tortilla quality attributes are diameter, opacity, and shelf stability, designated here as rollability or the ability to roll or fold the tortilla without cracking. In this study gliadin functionality in tortilla quality was studied using near-isogenic wheat lines that have deletions in either Gli A1, Gli D1, Gli A2, or Gli D2 gliadin loci. The deletion lines are designated by the same abbreviations. Dough and tortillas were prepared from the parent line used to derive these deletion lines, each individual deletion line, and a control commercial tortilla flour. Quantitative and qualitative evaluations were performed on the dough and tortillas derived from the flour from each of these lines. None of the deletions in the gliadin loci altered the shelf stability versus that found for the parent to the deletion lines or control tortilla flour. However, deletions in the Gli 2 loci, in particular Gli A2 reduced the relative proportion of alpha- and beta-gliadins with a greater cysteine amino acid content and gluten cross-link function versus the chain-terminating omega-gliadins in Gli 1, which were still present. As such, the dough and gluten matrix appeared to have greater extensibility, which improved the diameter and overall quality of the tortillas while not altering the rollability. Deletions in the Gli 1 loci had the opposite result with increased cross-linking of alpha- and beta-gliadins, polymeric protein content, and a stronger dough that decreased the diameter and overall quality of the tortillas. The data suggest that altering certain Gli 2 loci through null alleles could be a viable strategy to develop cultivars improved for the specific functionality requirements needed for the rapidly growing tortilla market.

Stabilizing detached Bridgman melt crystal growth: Model-based nonlinear feedback control

NASA Astrophysics Data System (ADS)

Yeckel, Andrew; Daoutidis, Prodromos; Derby, Jeffrey J.

2012-12-01

The dynamics and operability limits of a nonlinear-proportional-integral controller designed to stabilize detached vertical Bridgman crystal growth are studied. The manipulated variable is the pressure difference between upper and lower vapor spaces, and the controlled variable is the gap width at the triple-phase line. The controller consists of a model-based nonlinear component coupled with a standard proportional-integral controller. The nonlinear component is based on a capillary model of shape stability. Perturbations to gap width, pressure difference, wetting angle, and growth angle are studied under both shape stable and shape unstable conditions. The nonlinear-PI controller allows a wider operating range of gain than a standard PI controller used alone, is easier to tune, and eliminates solution multiplicity from closed-loop operation.

14 CFR 25.231 - Longitudinal stability and control.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Longitudinal stability and control. 25.231... Characteristics § 25.231 Longitudinal stability and control. (a) Landplanes may have no uncontrollable tendency to... on concrete, to maintain any attitude up to thrust line level, at 75 percent of V SR 1. (b) For...

14 CFR 25.231 - Longitudinal stability and control.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Longitudinal stability and control. 25.231... Characteristics § 25.231 Longitudinal stability and control. (a) Landplanes may have no uncontrollable tendency to... on concrete, to maintain any attitude up to thrust line level, at 75 percent of V SR 1. (b) For...

14 CFR 25.231 - Longitudinal stability and control.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Longitudinal stability and control. 25.231... Characteristics § 25.231 Longitudinal stability and control. (a) Landplanes may have no uncontrollable tendency to... on concrete, to maintain any attitude up to thrust line level, at 75 percent of V SR 1. (b) For...

14 CFR 25.231 - Longitudinal stability and control.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Longitudinal stability and control. 25.231... Characteristics § 25.231 Longitudinal stability and control. (a) Landplanes may have no uncontrollable tendency to... on concrete, to maintain any attitude up to thrust line level, at 75 percent of V SR 1. (b) For...

46 CFR 172.065 - Damage stability.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Damage stability. 172.065 Section 172.065 Shipping COAST... § 172.065 Damage stability. (a) Definitions. As used in this section, Length or L means load line length... paragraph (c) of this section, assuming the damage specified in paragraph (d) of this section. (c...

46 CFR 172.065 - Damage stability.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Damage stability. 172.065 Section 172.065 Shipping COAST... § 172.065 Damage stability. (a) Definitions. As used in this section, Length or L means load line length... paragraph (c) of this section, assuming the damage specified in paragraph (d) of this section. (c...

46 CFR 172.065 - Damage stability.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Damage stability. 172.065 Section 172.065 Shipping COAST... § 172.065 Damage stability. (a) Definitions. As used in this section, Length or L means load line length... paragraph (c) of this section, assuming the damage specified in paragraph (d) of this section. (c...

46 CFR 171.015 - Location of margin line.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Location of margin line. 171.015 Section 171.015 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO VESSELS CARRYING PASSENGERS General § 171.015 Location of margin line. (a) A vessel with a...

Actin-Binding Protein Requirement for Cortical Stability and Efficient Locomotion

NASA Astrophysics Data System (ADS)

Cunningham, C. Casey; Gorlin, Jed B.; Kwiatkowski, David J.; Hartwig, John H.; Janmey, Paul A.; Randolph Byers, H.; Stossel, Thomas P.

1992-01-01

Three unrelated tumor cell lines derived from human malignant melanomas lack actin-binding protein (ABP), which cross-links actin filaments in vitro and connects these filaments to plasma membrane glycoproteins. The ABP-deficient cells have impaired locomotion and display circumferential blebbing of the plasma membrane. Expression of ABP in one of the lines after transfection restored translocational motility and reduced membrane blebbing. These findings establish that ABP functions to stabilize cortical actin in vivo and is required for efficient cell locomotion.

Stability and Control Characteristics of a Complete Airplane Model Having a Wing with Quarter-chord Line Swept Back 40 Degrees, Aspect Ratio 2.50, and Taper Ratio 0.42

NASA Technical Reports Server (NTRS)

Schulderfrei, Marvin; Comisarow, Paul; Goodson, Kenneth W

1951-01-01

An investigation has been made of a complete airplane model having a wing with the quarter-chord line swept back 40 degrees, aspect ratio 2.50, and taper ratio 0.42 to determine its low-speed stability and control characteristics. The longitudinal stability investigation included stabilizer and tail-off tests with different wing dihedral angles (Gamma = 0 degrees and Gamma = -10 degrees) over an angle-of-attack range for the cruising and landing configurations and tests. with a high horizontal-tail location (Gamma = -10 degrees) for the cruising configuration. Tests were made of the wing alone and to determine the effect of wing end plates in pitch. Lateral stability characteristics were determined for the airplane with different geometric wing dihedrals, with end plates, and with several dorsal modifications. Tests were made with ailerons and spoilers to determine control characteristics.

A gimbal platform stabilization for topographic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michele, Mangiameli, E-mail: michele.mangiameli@dica.unict.it; Giuseppe, Mussumeci

2015-03-10

The aim of this work is the stabilization of a Gimbal platform for optical sensors acquisitions in topographic applications using mobile vehicles. The stabilization of the line of sight (LOS) consists in tracking the command velocity in presence of nonlinear noise due to the external environment. The hardware architecture is characterized by an Ardupilot platform that allows the control of both the mobile device and the Gimbal. Here we developed a new approach to stabilize the Gimbal platform, which is based on neural network. For the control system, we considered a plant that represents the transfer function of the servomore » system control model for an inertial stabilized Gimbal platform. The transductor used in the feed-back line control is characterized by the Rate Gyro transfer function installed onboard of Ardupilot. For the simulation and investigation of the system performance, we used the Simulink tool of Matlab. Results show that the hardware/software approach is efficient, reliable and cheap for direct photogrammetry, as well as for general purpose applications using mobile vehicles.« less

Microtubule-stabilizing properties of the avocado-derived toxins (+)-(R)-persin and (+)-(R)-tetrahydropersin in cancer cells and activity of related synthetic analogs.

PubMed

Field, Jessica J; Kanakkanthara, Arun; Brooke, Darby G; Sinha, Saptarshi; Pillai, Sushila D; Denny, William A; Butt, Alison J; Miller, John H

2016-06-01

The avocado toxin (+)-R-persin (persin) is active at low micromolar concentrations against breast cancer cells and synergizes with the estrogen receptor modulator 4-hydroxytamoxifen. Previous studies in the estrogen receptor-positive breast cancer cell line MCF-7 indicate that persin acts as a microtubule-stabilizing agent. In the present study, we further characterize the properties of persin and several new synthetic analogues in human ovarian cancer cells. Persin and tetrahydropersin cause G2M cell cycle arrest and increase intracellular microtubule polymerization. One analog (4-nitrophenyl)-deshydroxypersin prevents cell proliferation and blocks cells in G1 of the cell cycle rather than G2M, suggesting an additional mode of action of these compounds independent of microtubules. Persin can synergize with other microtubule-stabilizing agents, and is active against cancer cells that overexpress the P-glycoprotein drug efflux pump. Evidence from Flutax-1 competition experiments suggests that while the persin binding site on β-tubulin overlaps the classical taxoid site where paclitaxel and epothilone bind, persin retains activity in cell lines with single amino acid mutations that affect these other taxoid site ligands. This implies the existence of a unique binding location for persin at the taxoid site.

Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin

PubMed Central

Oulhen, Nathalie; Wessel, Gary M.

2016-01-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells. In the sea urchin, Strongylocentrotus purpuratus (Sp), Nanos 2 mRNA is broadly transcribed but accumulates specifically in the small micromere (sMic) lineage, in part because of the 3′UTR element GNARLE leads to turnover in somatic cells but retention in the sMics. Here we found that the Nanos 2 protein is also selectively stabilized; it is initially translated throughout the embryo but turned over in the future somatic cells and retained only in the sMics, the future germ line in this animal. This differential stability of Nanos protein is dependent on the open reading frame (ORF), and is independent of the sumoylation and ubiquitylation pathways. Manipulation of the ORF indicates that 68 amino acids in the N terminus of the Nanos protein are essential for its stability in the sMics whereas a 45 amino acid element adjacent to the zinc fingers targets its degradation. Further, this regulation of Nanos protein is cell autonomous, following formation of the germ line. These results are paradigmatic for the unique presence of Nanos in the germ line by a combination of selective RNA retention, distinctive translational control mechanisms (Oulhen et al., 2013), and now also by defined Nanos protein stability. PMID:27424271

Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin.

PubMed

Oulhen, Nathalie; Wessel, Gary M

2016-10-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells. In the sea urchin, Strongylocentrotus purpuratus (Sp), Nanos 2 mRNA is broadly transcribed but accumulates specifically in the small micromere (sMic) lineage, in part because of the 3'UTR element GNARLE leads to turnover in somatic cells but retention in the sMics. Here we found that the Nanos 2 protein is also selectively stabilized; it is initially translated throughout the embryo but turned over in the future somatic cells and retained only in the sMics, the future germ line in this animal. This differential stability of Nanos protein is dependent on the open reading frame (ORF), and is independent of the sumoylation and ubiquitylation pathways. Manipulation of the ORF indicates that 68 amino acids in the N terminus of the Nanos protein are essential for its stability in the sMics whereas a 45 amino acid element adjacent to the zinc fingers targets its degradation. Further, this regulation of Nanos protein is cell autonomous, following formation of the germ line. These results are paradigmatic for the unique presence of Nanos in the germ line by a combination of selective RNA retention, distinctive translational control mechanisms (Oulhen et al., 2013), and now also by defined Nanos protein stability. Copyright © 2016 Elsevier Inc. All rights reserved.

Line Shapes and Intensities of Carbon Monoxide Transitions in the (3→0) and (4→1) Bands

NASA Astrophysics Data System (ADS)

Reed, Zachary; Polyansky, Oleg; Hodges, Joseph T.

2017-06-01

We have measured several carbon monoxide transitions in the (3→0) and (4→1) band using frequency stabilized cavity ringdown spectroscopy (FS-CRDS). The measured transitions are compared to the line strength values in HITRAN 2012 [1], those determined by Wojtewitz et al [2], and to theoretical calculations. The cavity length is actively locked to an iodine stabilized HeNe laser, providing long term frequency stability of 10 kHz and is linked to a self-referenced, octave-spanning frequency comb. The temperature of the optical cavity is actively regulated at the mK level, and the pressure measurements are SI-traceable. The sample is a NIST calibrated reference mixture of 11.98575(95)% CO in N_{2}. The absorption spectra are modeled using the Hartmann-Tran profile (HTP). The SNR in these spectra may exceed 10,000:1, which necessitates including the effects of speed dependence, collisional narrowing, and correlation between velocity-changing and dephasing collisions. The relative uncertainties of the line strengths calculated in this study are better than 0.1%. There are systematic differences on the 1% level for ^{12}CO against both HITRAN [1] and the previous work by Wojtewitz et al [2]. The measurement uncertainties are nearly an order of magnitude lower than previous results. Additionally, the relative uncertainties in the integrated areas of selected ^{12}CO and ^{13}CO transitions are less than 0.006% and 0.02%, respectively, providing an excellent test case for determination of isotope ratios by direct use of theoretical line intensity calculations. [1] Wojtewicz, S., et al., J Quant Spect and Rad Trans,2013. 130: p.191-200. [2]Rothman, L.S., et al., Journal of Quant Spect and Rad Trans, 2013. 130: p. 4-50.

Kinetic measures of restabilisation during volitional stepping reveal age-related alterations in the control of mediolateral dynamic stability.

PubMed

Singer, Jonathan C; McIlroy, William E; Prentice, Stephen D

2014-11-07

Research examining age-related changes in dynamic stability during stepping has recognised the importance of the restabilisation phase, subsequent to foot-contact. While regulation of the net ground reaction force (GRFnet) line of action is believed to influence dynamic stability during steady-state locomotion, such control during restabilisation remains unknown. This work explored the origins of age-related decline in mediolateral dynamic stability by examining the line of action of GRFnet relative to the centre of mass (COM) during restabilisation following voluntary stepping. Healthy younger and older adults (n=20 per group) performed three single-step tasks (varying speed and step placement), altering the challenge to stability control. Age-related differences in magnitude and intertrial variability of the angle of divergence of GRFnet line of action relative to the COM were quantified, along with the peak mediolateral and vertical GRFnet components. The angle of divergence was further examined at discrete points during restabilisation, to uncover events of potential importance to stability control. Older adults exhibited a reduced angle of divergence throughout restabilisation. Temporal and spatial constraints on stepping increased the magnitude and intertrial variability of the angle of divergence, although not differentially among the older adults. Analysis of the time-varying angle of divergence revealed age-related reductions in magnitude, with increases in timing and intertrial timing variability during the later phase of restabilisation. This work further supports the idea that age-related challenges in lateral stability control emerge during restabilisation. Age-related alterations during the later phase of restabilisation may signify challenges with reactive control. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design and Synthesis of 2-Heterocyclyl-3-arylthio-1H-indoles as Potent Tubulin Polymerization and Cell Growth Inhibitors with Improved Metabolic Stability

PubMed Central

La Regina, Giuseppe; Bai, Ruoli; Rensen, Willeke; Coluccia, Antonio; Piscitelli, Francesco; Gatti, Valerio; Bolognesi, Alessio; Lavecchia, Antonio; Granata, Ilaria; Porta, Amalia; Maresca, Bruno; Soriani, Alessandra; Iannitto, Maria Luisa; Mariani, Marisa; Santoni, Angela; Brancale, Andrea; Ferlini, Cristiano; Dondio, Giulio; Varasi, Mario; Mercurio, Ciro; Hamel, Ernest; Lavia, Patrizia; Novellino, Ettore; Silvestri, Romano

2011-01-01

New arylthioindoles (ATIs) were obtained by replacing the 2-alkoxycarbonyl group with a bioisosteric 5-membered heterocycle nucleus. The new ATIs 5, 8, and 10 inhibited tubulin polymerization, reduced cell growth of a panel of human transformed cell lines, and showed higher metabolic stability than the reference ester 3. These compounds induced mitotic arrest and apoptosis at a similar level as combretastatin A-4 and vinblastine and triggered caspase-3 expression in a significant fraction of cells in both p53-proficient and p53-defective cell lines. Importantly, ATIs 5, 8, and 10 were more effective than vinorelbine, vinblastine, and paclitaxel as growth inhibitors of the P-glycoprotein-overexpressing cell line NCI/ADR-RES. Compound 5 was shown to have medium metabolic stability in both human and mouse liver microsomes, in contrast to the rapidly degraded reference ester 3, and a pharmacokinetic profile in the mouse characterized by a low systemic clearance and excellent oral bioavailability. PMID:22044164

Biomechanical stability of intramedullary technique for fixation of joint depressed calcaneus fracture.

PubMed

Nelson, Joshua D; McIff, Terence E; Moodie, Patrick G; Iverson, Jamey L; Horton, Greg A

2010-03-01

Internal fixation of the os calcis is often complicated by prolonged soft tissue management and posterior facet disruption. An ideal calcaneal construct would include minimal hardware prominence, sturdy posterior facet fixation and nominal soft tissue disruption. The purpose of this study was to develop such a construct and provide a biomechanical analysis comparing our technique to a standard internal fixation technique. Twenty fresh-frozen cadaver calcanei were used to create a reproducible Sanders type-IIB calcaneal fracture pattern. One calcaneus of each pair was randomly selected to be fixed using our compressive headless screw technique. The contralateral matched calcaneus was fixed with a nonlocking calcaneal plate in a traditional fashion. Each calcaneus was cyclically loaded at a frequency of 1 Hz for 4000 cycles using an increasing force from 250 N to 1000 N. An Optotrak motion capturing system was used to detect relative motion of the three fracture fragments at eight different points along the fracture lines. Horizontal separation and vertical displacement at the fracture lines was recorded, as well as relative rotation at the primary fracture line. When the data were averaged, there was more horizontal displacement at the primary fracture line of the plate and screw construct compared to the headless screw construct. The headless screw construct also had less vertical displacement at the primary fracture line at every load. On average those fractures fixed with the headless screw technique had less rotation than those fixed with the side plate technique. A new headless screw technique for calcaneus fracture fixation was shown to provide stability as good as, or better than, a standard side plating technique under the axial loading conditions of our model. Although further testing is needed, the stability of the proposed technique is similar to that typically provided by intramedullary fixation. This fixation technique provides a biomechanically stable construct with the potential for a minimally invasive approach and improved post-operative soft tissue healing.

X Chromosome Crossover Formation and Genome Stability in Caenorhabditis elegans Are Independently Regulated by xnd-1

PubMed Central

McClendon, T. Brooke; Mainpal, Rana; Amrit, Francis R. G.; Krause, Michael W.; Ghazi, Arjumand; Yanowitz, Judith L.

2016-01-01

The germ line efficiently combats numerous genotoxic insults to ensure the high fidelity propagation of unaltered genomic information across generations. Yet, germ cells in most metazoans also intentionally create double-strand breaks (DSBs) to promote DNA exchange between parental chromosomes, a process known as crossing over. Homologous recombination is employed in the repair of both genotoxic lesions and programmed DSBs, and many of the core DNA repair proteins function in both processes. In addition, DNA repair efficiency and crossover (CO) distribution are both influenced by local and global differences in chromatin structure, yet the interplay between chromatin structure, genome integrity, and meiotic fidelity is still poorly understood. We have used the xnd-1 mutant of Caenorhabditis elegans to explore the relationship between genome integrity and crossover formation. Known for its role in ensuring X chromosome CO formation and germ line development, we show that xnd-1 also regulates genome stability. xnd-1 mutants exhibited a mortal germ line, high embryonic lethality, high incidence of males, and sensitivity to ionizing radiation. We discovered that a hypomorphic allele of mys-1 suppressed these genome instability phenotypes of xnd-1, but did not suppress the CO defects, suggesting it serves as a separation-of-function allele. mys-1 encodes a histone acetyltransferase, whose homolog Tip60 acetylates H2AK5, a histone mark associated with transcriptional activation that is increased in xnd-1 mutant germ lines, raising the possibility that thresholds of H2AK5ac may differentially influence distinct germ line repair events. We also show that xnd-1 regulated him-5 transcriptionally, independently of mys-1, and that ectopic expression of him-5 suppressed the CO defects of xnd-1. Our work provides xnd-1 as a model in which to study the link between chromatin factors, gene expression, and genome stability. PMID:27678523

Stability of Contact Lines in Fluids: 2D Stokes Flow

NASA Astrophysics Data System (ADS)

Guo, Yan; Tice, Ian

2018-02-01

In an effort to study the stability of contact lines in fluids, we consider the dynamics of an incompressible viscous Stokes fluid evolving in a two-dimensional open-top vessel under the influence of gravity. This is a free boundary problem: the interface between the fluid in the vessel and the air above (modeled by a trivial fluid) is free to move and experiences capillary forces. The three-phase interface where the fluid, air, and solid vessel wall meet is known as a contact point, and the angle formed between the free interface and the vessel is called the contact angle. We consider a model of this problem that allows for fully dynamic contact points and angles. We develop a scheme of a priori estimates for the model, which then allow us to show that for initial data sufficiently close to equilibrium, the model admits global solutions that decay to equilibrium exponentially quickly.

Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing.

PubMed

Borri, Simone; Siciliani de Cumis, Mario; Insero, Giacomo; Bartalini, Saverio; Cancio Pastor, Pablo; Mazzotti, Davide; Galli, Iacopo; Giusfredi, Giovanni; Santambrogio, Gabriele; Savchenkov, Anatoliy; Eliyahu, Danny; Ilchenko, Vladimir; Akikusa, Naota; Matsko, Andrey; Maleki, Lute; De Natale, Paolo

2016-02-17

The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF₂ microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.

Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing

PubMed Central

Borri, Simone; Siciliani de Cumis, Mario; Insero, Giacomo; Bartalini, Saverio; Cancio Pastor, Pablo; Mazzotti, Davide; Galli, Iacopo; Giusfredi, Giovanni; Santambrogio, Gabriele; Savchenkov, Anatoliy; Eliyahu, Danny; Ilchenko, Vladimir; Akikusa, Naota; Matsko, Andrey; Maleki, Lute; De Natale, Paolo

2016-01-01

The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF2 microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line. PMID:26901199

Characterizing Excavation Damaged Zone and Stability of Pressurized Lined Rock Caverns for Underground Compressed Air Energy Storage

NASA Astrophysics Data System (ADS)

Kim, Hyung-Mok; Rutqvist, Jonny; Jeong, Ju-Hwan; Choi, Byung-Hee; Ryu, Dong-Woo; Song, Won-Kyong

2013-09-01

In this paper, we investigate the influence of the excavation damaged zone (EDZ) on the geomechanical performance of compressed air energy storage (CAES) in lined rock caverns. We conducted a detailed characterization of the EDZ in rock caverns that have been excavated for a Korean pilot test program on CAES in (concrete) lined rock caverns at shallow depth. The EDZ was characterized by measurements of P- and S-wave velocities and permeability across the EDZ and into undisturbed host rock. Moreover, we constructed an in situ concrete lining model and conducted permeability measurements in boreholes penetrating the concrete, through the EDZ and into the undisturbed host rock. Using the site-specific conditions and the results of the EDZ characterization, we carried out a model simulation to investigate the influence of the EDZ on the CAES performance, in particular related to geomechanical responses and stability. We used a modeling approach including coupled thermodynamic multiphase flow and geomechanics, which was proven to be useful in previous generic CAES studies. Our modeling results showed that the potential for inducing tensile fractures and air leakage through the concrete lining could be substantially reduced if the EDZ around the cavern could be minimized. Moreover, the results showed that the most favorable design for reducing the potential for tensile failure in the lining would be a relatively compliant concrete lining with a tight inner seal, and a relatively stiff (uncompliant) host rock with a minimized EDZ. Because EDZ compliance depends on its compressibility (or modulus) and thickness, care should be taken during drill and blast operations to minimize the damage to the cavern walls.

GAPD and tubulin are suitable internal controls for qPCR analysis of oral squamous cell carcinoma cell lines.

PubMed

Campos, M S; Rodini, C O; Pinto-Júnior, D S; Nunes, F D

2009-02-01

The selection of housekeeping genes is critical for gene expression studies. To address this issue, four candidate housekeeping genes, including several commonly used ones, were investigated in oral squamous cell carcinoma cell lines. A simple quantitative RT-PCR approach was employed by comparing relative expression of the four candidate genes within two cancerous cell lines (HN6 and HN31) and one noncancerous cell line (HaCaT) treated or not with EGF and TGF-beta1. Data were analyzed using ANOVA followed by the NormFinder software program. On this basis, stability of the candidate housekeeping genes was ranked and non statistical differences were found using ANOVA test. On the other hand, the NormFinder was able to show that GAPD and TUBB presented the less variable results, representing appropriated housekeeping genes for the samples and conditions analyzed. In conclusion, this study suggests that the GAPD and the TUBB represent adequate normalizers for gene profiling studies in OSCC cell lines, covering, respectively, high and low expression levels genes.

In vitro evaluation of (99m)Tc-EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines.

PubMed

Yurt Lambrecht, Fatma; Durkan, Kübra; Ozgür, Aykut; Gündüz, Cumhur; Avcı, Cığır Biray; Susluer, Sunde Yılmaz

2013-05-01

Bombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. (99m)Tc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of (99m)Tc-EDDA-HYNIC-Q-Litorin and (99m)Tc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a radiopharmaceutical for pancreatic tumor imaging.

TUNNEL LINING DESIGN METHOD BY FRAME STRUCTURE ANALYSIS USING GROUND REACTION CURVE

NASA Astrophysics Data System (ADS)

Sugimoto, Mitsutaka; Sramoon, Aphichat; Okazaki, Mari

Both of NATM and shield tunnelling method can be applied to Diluvial and Neogene deposit, on which mega cities are located in Japan. Since the lining design method for both tunnelling methods are much different, the unified concept for tunnel lining design is expected. Therefore, in this research, a frame structure analysis model for tunnel lining design using the ground reaction curve was developed, which can take into account the earth pressure due to excavated surface displacement to active side including the effect of ground self-stabilization, and the excavated surface displacement before lining installation. Based on the developed model, a parameter study was carried out taking coefficient of subgrade reaction and grouting rate as a parameter, and the measured earth pressure acting on the lining at the site was compared with the calculated one by the developed model and the conventional model. As a result, it was confirmed that the developed model can represent earth pressure acting on the lining, lining displacement, and lining sectional force at ground ranging from soft ground to stiff ground.

Thermostability analysis of line-tension-associated nucleation at a gas-liquid interface.

PubMed

Singha, Sanat Kumar; Das, Prasanta Kumar; Maiti, Biswajit

2017-01-01

The influence of line tension on the thermostability of a droplet nucleated from an oversaturated vapor at the interface of the vapor and another immiscible liquid is investigated. Along with the condition of mechanical equilibrium, the notion of extremization of the reversible work of formation is considered to obtain the critical parameters related to heterogeneous nucleation. From the energetic formulation, the critical reversible work of formation is found to be greater than that of homogeneous nucleation for high value of the positive line tension. On the other hand, for high value of the negative line tension, the critical reversible work of formation becomes negative. Therefore, these thermodynamic instabilities under certain substrate wettability situations necessitate a free-energetics-based stability of the nucleated droplet, because the system energy is not minimized under these conditions. This thermostability is analogous to the transition-based stability proposed by Widom [B. Widom, J. Phys. Chem. 99, 2803 (1995)]10.1021/j100009a041 in the case of partial wetting phenomena along with the positive line tension. The thermostability analysis limits the domain of the solution space of the present critical-value problem as the thermodynamic transformation in connection with homogeneous and workless nucleation is considered. Within the stability range of the geometry-based wetting parameters, three limiting modes of nucleation, i.e., total-dewetting-related homogeneous nucleation, and total-wetting-associated and total-submergence-associated workless nucleation scenarios, are identified. Either of the two related limiting wetting scenarios of workless nucleation, namely, total wetting and total submergence, is found to be favorable depending on the geometry-based wetting conditions. The line-tension-associated nucleation on a liquid surface can be differentiated from that on a rigid substrate, as in the former, the stability based on mechanical equilibrium and a typical case of workless nucleation with complete submergence are observed.

Direct inkjet printing of miniaturized luminescent YAG:Er3+ from sol-gel precursor

NASA Astrophysics Data System (ADS)

Hong, Yuzhe; Chen, Zhaoxi; Trofimov, Artem A.; Lei, Jincheng; Chen, Jie; Yuan, Lei; Zhu, Wenge; Xiao, Hai; Xu, Dong; Jacobsohn, Luiz G.; Kornev, Konstantin G.; Bordia, Rajendra K.; Peng, Fei

2017-06-01

This work focuses on demonstrating the fabrication of miniaturized scintillators based on rare earth activated YAG ceramics using the direct inkjet printing method. Erbium was chosen as the activator, and YAG sol-gel precursor inks were prepared under precise hydrolysis and polycondensation reactions. The precursors showed excellent control over rheology and surface tension, resulting in good printability. One of the most important challenges of inkjet printing of lines is the stability of lines. Line stability during printing is highly dependent on the printing frequency, drop spacing and substrate temperature. When a line was printed drop by drop, bulges were always observed during printing at 25 °C. This instability was significantly suppressed when the substrates were slightly heated. Adding polyvinylpyrrolidone to the precursor helped eliminate pores and cracks during firing. Crack-free YAG lines with ∼200 nm thickness were obtained after firing. The photoluminescence of YAG:Er heat-treated at 1200 °C for 1 h was optimized for an Er concentration of 2 wt%. X-ray induced radioluminescence was dominated by emission lines at 398 and 567 nm.

Optimization of Kink Stability in High-Beta Quasi-axisymmetric Stellarators

NASA Astrophysics Data System (ADS)

Fu, G. Y.; Ku, L.-P.; Manickam, J.; Cooper, W. A.

1998-11-01

A key issue for design of Quasi-axisymmetric stellarators( A. Reiman et al, this conference.) (QAS) is the stability of external kink modes driven by pressure-induced bootstrap current. In this work, the 3D MHD stability code TERPSICHORE(W.A. Cooper, Phys. Plasmas 3), 275(1996). is used to calculate the stability of low-n external kink modes in a high-beta QAS. The kink stability is optimized by adjusting plasma boundary shape (i.e., external coil configuration) as well as plasma pressure and current profiles. For this purpose, the TERPSICHORE code has been implemented successfully in an optimizer which maximizes kink stability as well as quasi-symmetry. A key factor for kink stability is rotational transform profile. It is found that the edge magnetic shear is strongly stabilizing. The amount of the shear needed for complete stabilization increases with edge transform. It is also found that the plasma boundary shape plays an important role in the kink stability besides transform profile. The physics mechanisms for the kink stability are being studied by examining the contributions of individual terms in δ W of the energy principle: the field line bending term, the current-driven term, the pressure-driven term, and the vacuum term. Detailed results will be reported.

Direct Adaptive Aircraft Control Using Dynamic Cell Structure Neural Networks

NASA Technical Reports Server (NTRS)

Jorgensen, Charles C.

1997-01-01

A Dynamic Cell Structure (DCS) Neural Network was developed which learns topology representing networks (TRNS) of F-15 aircraft aerodynamic stability and control derivatives. The network is integrated into a direct adaptive tracking controller. The combination produces a robust adaptive architecture capable of handling multiple accident and off- nominal flight scenarios. This paper describes the DCS network and modifications to the parameter estimation procedure. The work represents one step towards an integrated real-time reconfiguration control architecture for rapid prototyping of new aircraft designs. Performance was evaluated using three off-line benchmarks and on-line nonlinear Virtual Reality simulation. Flight control was evaluated under scenarios including differential stabilator lock, soft sensor failure, control and stability derivative variations, and air turbulence.

Use of JOINTBOND(R) as a center line joint stabilizer demonstration on I-95 N.B., Waterville to Clinton, Maine.

DOT National Transportation Integrated Search

2013-09-01

The objective of this study is to determine if JOINTBOND extends the useful life of the construction joint by : reducing permeability at the joint. : The manufacturer claims that JOINTBOND penetrates and fortifies the weakest area in new asphalt ...

Rapid development of stable transgene CHO cell lines by CRISPR/Cas9-mediated site-specific integration into C12orf35.

PubMed

Zhao, Menglin; Wang, Jiaxian; Luo, Manyu; Luo, Han; Zhao, Meiqi; Han, Lei; Zhang, Mengxiao; Yang, Hui; Xie, Yueqing; Jiang, Hua; Feng, Lei; Lu, Huili; Zhu, Jianwei

2018-07-01

Chinese hamster ovary (CHO) cells are the most widely used mammalian hosts for recombinant protein production. However, by conventional random integration strategy, development of a high-expressing and stable recombinant CHO cell line has always been a difficult task due to the heterogenic insertion and its caused requirement of multiple rounds of selection. Site-specific integration of transgenes into CHO hot spots is an ideal strategy to overcome these challenges since it can generate isogenic cell lines with consistent productivity and stability. In this study, we investigated three sites with potential high transcriptional activities: C12orf35, HPRT, and GRIK1, to determine the possible transcriptional hot spots in CHO cells, and further construct a reliable site-specific integration strategy to develop recombinant cell lines efficiently. Genes encoding representative proteins mCherry and anti-PD1 monoclonal antibody were targeted into these three loci respectively through CRISPR/Cas9 technology. Stable cell lines were generated successfully after a single round of selection. In comparison with a random integration control, all the targeted integration cell lines showed higher productivity, among which C12orf35 locus was the most advantageous in both productivity and cell line stability. Binding affinity and N-glycan analysis of the antibody revealed that all batches of product were of similar quality independent on integrated sites. Deep sequencing demonstrated that there was low level of off-target mutations caused by CRISPR/Cas9, but none of them contributed to the development process of transgene cell lines. Our results demonstrated the feasibility of C12orf35 as the target site for exogenous gene integration, and strongly suggested that C12orf35 targeted integration mediated by CRISPR/Cas9 is a reliable strategy for the rapid development of recombinant CHO cell lines.

Investigation of synthesized new vanadium(III) complexes of ditolyldithiophosphate ligands by spectroscopic, cyclic voltammetric, DFT, antimicrobial and cytotoxic studies

NASA Astrophysics Data System (ADS)

Kumar, Sandeep; Syed, Atiya; Andotra, Savit; Kaur, Ramanpreet; Vikas; Pandey, Sushil K.

2018-02-01

Vanadium(III) complexes with sulfur donor dithiophosphate ligands corresponding to [{(ArO)2PS2}3V] and [{(ArO)2PS2}2VCl.L] (Ar = o-, m-, p-CH3C6H4 and p-Cl-m-CH3C6H3; L = NC5H5, P(C6H5)3, have been synthesized and characterized by various physico-chemical techniques like elemental analyses, magnetic studies, ESI-Mass, IR, UV and heteronuclear NMR (1H, 13C and 31P) spectral studies. These analyses have contributed to the prediction of structure: by exhibiting significant v(P-S) and v(Pdbnd S) band shifting in comparative IR spectra; shifting of resonance signal in comparative 31P NMR spectra of ligands and complexes and stability of V(III) ion in the complexed state is confirmed by magnetic and UV studies. Therefore, the six coordinated geometry stabilizing the trivalent vanadium atom in the complexes and adducts, respectively has been confirmed. The cyclic voltammetric analyses presented the redox aptitude of the complex under analysis which can be utilized as catalyst in organic synthesis. The geometry of ligands and complexes has been optimized using density functional theory (DFT). The structural parameters, vibrational bands and energy gaps of frontier orbitals (HOMO-LUMO) have also been calculated. The calculated geometric and spectral results reproduced the experimental data with well agreement. The DFT computed frontier molecular orbitals (HOMO-LUMO) and their energies suggest charge transfer occurs within the complexes. Antimicrobial screening of the complexes against two bacterial strains: Gram-positive, Enterrococcus faecalis and Gram-negative, Eischerichia coli and fungus Fusarium oxysporum have shown potential bioactivity. A preliminary cytotoxic analysis has been carried out using the cultivated human cell lines: lung adeno carcinoma cell line A-549, leukemia cell line THP-1, prostate cancer cell line PC3 and colorectal cancer cell line HCT-116.

Thermo-oxidative stability studies of PMR-15 polymer matrix composites reinforced with various fibers

NASA Technical Reports Server (NTRS)

Bowles, Kenneth J.

1990-01-01

An experimental study was conducted to measure the thermo-oxidative stability of PMR-15 polymer matrix composites reinforced with various fibers and to observe differences in the way they degrade in air. The fibers that were studied included graphite and the thermally stable Nicalon and Nextel ceramic fibers. Weight loss rates for the different composites were assessed as a function of mechanical properties, specimen geometry, fiber sizing, and interfacial bond strength. Differences were observed in rates of weight loss, matrix cracking, geometry dependency, and fiber-sizing effects. It was shown that Celion 6000 fiber-reinforced composites do not exhibit a straight-line Arrhenius relationship at temperatures above 316 C.

Processed pseudogenes of human endogenous retroviruses generated by LINEs: their integration, stability, and distribution.

PubMed

Pavlícek, Adam; Paces, Jan; Elleder, Daniel; Hejnar, Jirí

2002-03-01

We report here the presence of numerous processed pseudogenes derived from the W family of endogenous retroviruses in the human genome. These pseudogenes are structurally colinear with the retroviral mRNA followed by a poly(A) tail. Our analysis of insertion sites of HERV-W processed pseudogenes shows a strong preference for the insertion motif of long interspersed nuclear element (LINE) retrotransposons. The genomic distribution, stability during evolution, and frequent truncations at the 5' end resemble those of the pseudogenes generated by LINEs. We therefore suggest that HERV-W processed pseudogenes arose by multiple and independent LINE-mediated retrotransposition of retroviral mRNA. These data document that the majority of HERV-W copies are actually nontranscribed promoterless pseudogenes. The current search for HERV-Ws associated with several human diseases should concentrate on a small subset of transcriptionally competent elements.

Laser based thermo-conductometry as an approach to determine ribbon solid fraction off-line and in-line.

PubMed

Wiedey, Raphael; Šibanc, Rok; Kleinebudde, Peter

2018-06-06

Ribbon solid fraction is one of the most important quality attributes during roll compaction/dry granulation. Accurate and precise determination is challenging and no in-line measurement tool has been generally accepted, yet. In this study, a new analytical tool with potential off-line as well as in-line applicability is described. It is based on the thermo-conductivity of the compacted material, which is known to depend on the solid fraction. A laser diode was used to punctually heat the ribbon and the heat propagation monitored by infrared thermography. After performing a Gaussian fit of the transverse ribbon profile, the scale parameter σ showed correlation to ribbon solid fraction in off-line as well as in-line studies. Accurate predictions of the solid fraction were possible for a relevant range of process settings. Drug stability was not affected, as could be demonstrated for the model drug nifedipine. The application of this technique was limited when using certain fillers and working at higher roll speeds. This study showed the potentials of this new technique and is a starting point for additional work that has to be done to overcome these challenges. Copyright © 2018 Elsevier B.V. All rights reserved.

Stability of handwriting performance following injury-induced hand-dominance transfer in adults: a pilot study.

PubMed

Yancosek, Kathleen E; Mullineaux, David R

2011-01-01

The aim of this study was to quantify stability of nondominant handwriting kinematics and legibility in participants with functional loss of the previously dominant hand. Twelve adult volunteers provided two handwriting samples 6 weeks apart. Handwriting tasks (Compose a Sentence, Copy Alphabet, Copy Date, Copy Sentence, and Draw Circles) were performed in cursive writing on standard white, lined paper taped to a digitizer to record kinematic and kinetic variables of velocity, displacement, force, and on-paper time. Results showed minimal performance variability within subjects and marked variability between subjects, as well as variability between tasks for all participants. Stylistic stability of the handwriting samples was assessed by two independent evaluators. These evaluators matched all handwriting samples at test to retest times with 89%-100% accuracy, suggesting value in the "whole" handwriting sample and emphasizing the idiosyncratic nature of handwriting. Results suggest that handwriting skill stability in the previously nondominant hand varies across subjects and task demands.

Wavelength locking of CW and Q-switched Er(3+) microchip lasers to acetylene absorption lines using pump-power modulation.

PubMed

Brunel, Marc; Vallet, Marc

2007-02-19

We show that modulating the diode-pump power of a microchip solid-state laser enables to lock its wavelength to a reference molecular line. The method is applied to two different types of Er,Yb:glass monolithic microchip lasers operating at 1.53 microm. First, wavelength locking of a continuous-wave dual-polarization microchip laser to acetylene absorption lines is demonstrated, without using any additional modulator, internal or external. We then show that, remarkably, this simple method is also suitable for stabilizing a passively Q-switched microchip laser. A pulsed wavelength stability of 10(-8) over 1 hour is readily observed. Applications to lidars and to microwave photonics are discussed.

Possible stabilization of the frequency of a CO/sub 2/ laser using an external Stark cell containing 1-1 difluoroethane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avtonomov, V.P.; Alexandrescu, R.; Dumitras, D.

1979-02-01

Results are presented of measurements of the Stark modulation index and absorption coefficient of CO/sub 2/ laser radiation due to the P (24) line by 1-1 difluorethane (C/sub 2/H/sub 4/F/sub 2/). The possibility of stabilizing the CO/sub 2/ laser frequency using a Stark cell is demonstrated and the laser frequency tuning efficiency within the P (24) line of the 00/sup 0/1--10/sup 0/0 transition is determined.

Single Bacterium Detection Using Sers

NASA Astrophysics Data System (ADS)

Gonchukov, S. A.; Baikova, T. V.; Alushin, M. V.; Svistunova, T. S.; Minaeva, S. A.; Ionin, A. A.; Kudryashov, S. I.; Saraeva, I. N.; Zayarny, D. A.

2016-02-01

This work is devoted to the study of a single Staphylococcus aureus bacterium detection using surface-enhanced Raman spectroscopy (SERS) and resonant Raman spectroscopy (RS). It was shown that SERS allows increasing sensitivity of predominantly low frequency lines connected with the vibrations of Amide, Proteins and DNA. At the same time the lines of carotenoids inherent to this kind of bacterium are well-detected due to the resonance Raman scattering mechanism. The reproducibility and stability of Raman spectra strongly depend on the characteristics of nanostructured substrate, and molecular structure and size of the tested biological object.

Experimental study on line-of-sight (LOS) attitude control using control moment gyros under micro-gravity environment

NASA Astrophysics Data System (ADS)

Kojima, Hirohisa; Hiraiwa, Kana; Yoshimura, Yasuhiro

2018-02-01

This paper presents the results of line-of-sight (LOS) attitude control using control moment gyros under a micro-gravity environment generated by parabolic flight. The W-Z parameters are used to describe the spacecraft attitude. In order to stabilize the current LOS to the target LOS, backstepping-based feedback control is considered using the W-Z parameters. Numerical simulations and experiments under a micro-gravity environment are carried out, and their results are compared in order to validate the proposed control methods.

A broadband chip-scale optical frequency synthesizer at 2.7 × 10−16 relative uncertainty

PubMed Central

Huang, Shu-Wei; Yang, Jinghui; Yu, Mingbin; McGuyer, Bart H.; Kwong, Dim-Lee; Zelevinsky, Tanya; Wong, Chee Wei

2016-01-01

Optical frequency combs—coherent light sources that connect optical frequencies with microwave oscillations—have become the enabling tool for precision spectroscopy, optical clockwork, and attosecond physics over the past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but Kerr nonlinear dynamics in high-Q solid-state microresonators has recently demonstrated promising features as alternative platforms. The advance not only fosters studies of chip-scale frequency metrology but also extends the realm of optical frequency combs. We report the full stabilization of chip-scale optical frequency combs. The microcomb’s two degrees of freedom, one of the comb lines and the native 18-GHz comb spacing, are simultaneously phase-locked to known optical and microwave references. Active comb spacing stabilization improves long-term stability by six orders of magnitude, reaching a record instrument-limited residual instability of 3.6mHz/τ. Comparing 46 nitride frequency comb lines with a fiber laser frequency comb, we demonstrate the unprecedented microcomb tooth-to-tooth relative frequency uncertainty down to 50 mHz and 2.7 × 10−16, heralding novel solid-state applications in precision spectroscopy, coherent communications, and astronomical spectrography. PMID:27152341

Determination of the elastic modulus of fly ash-based stabilizer applied in the trackbed

NASA Astrophysics Data System (ADS)

Lojda, Vít; Lidmila, Martin; Pýcha, Marek

2017-09-01

This paper describes a unique application of a fly ash-based stabilizer in the trackbed of a railway main line. The key goals of the stabilizer application are to protect the subgrade against the ingress of rain water, to increase the frost resistance and to remediate the natural ground constituted of weathered rock. The stabilizer was designed as a mixture of fly ash, generated as a waste material from coal plants, gypsum, calcium oxide and water. The mixture recipe was developed in a laboratory over several years. In 2005, a trial section of a railway line with subgrade consisting of clay limestone (weathered marlite) was built in the municipality of Smiřice. Since then, periodical measurements including collection of samples for laboratory evaluation of the fly ash-based stabilizer have taken place. Over the time span of the measurements, changes in mineral composition and development of fly ash transforming structures leading to the formation of C-A-S-H gel were detected. This paper describes the experimental laboratory investigation of the influence of dynamic loading on the elastic modulus of fly ash stabilizer samples and the development of permanent deformation of the samples with increasing number of loading cycles.

Novel topical BoNTA (CosmeTox, toxin type A) cream used to treat hyperfunctional wrinkles of the face, mouth, and neck.

PubMed

Chajchir, I; Modi, P; Chajchir, A

2008-09-01

This study aimed to compare the effect of the stabilized novel topical botulinum neurotoxin type A (BoNTA) cream (CosmeTox) and a placebo cream on subjects, to compare clinician-reported outcomes, and to assess the safety and utility of the novel topical BoNTA cream for treating the entire upper face, chin, and neck areas. This study randomized 40 female subjects to receive either topical BoNTA (CosmeTox) cream (2 U/ml) or an identical placebo cream (without BoNTA) on the face, chin, and neck areas. The subjects were followed for 12 weeks. The main outcome measures were the Facial Line Outcomes questionnaire scores and results from the Self-Perception of Age instrument, which assesses age of appearance relative to actual age. The BoNTA topical cream (CosmeTox) treatment produced significant improvements in the Facial Lines Outcome scores, which were maintained throughout the study period and lasted more than 3 months. The BoNTA topical cream treatment also reduced the age of appearance for a majority of subjects. The placebo had no effect on any measure. No serious adverse events occurred during the entire study period. Topical treatment with the stabilized BoNTA cream (CosmeTox) to the entire upper facial lines resulted in significantly improved facial features and age appearance, as measured by the subjects and clinicians. The BoNTA cream (CosmeTox) resulted in a significantly younger, more satisfying, relaxed appearance.

Effects of Goal Line Feedback on Level, Slope, and Stability of Performance within Curriculum-Based Measurement.

ERIC Educational Resources Information Center

Fuchs, Lynn S.; And Others

1991-01-01

Nineteen special educators implemented Curriculum-Based Measurement with a total of 36 learning-disabled math pupils in grades 2-8 to examine the effects of goal line feedback. Results indicated comparable levels and slopes of student performance across treatment conditions, although goal line feedback was associated with greater performance…

Low-dose AgNPs reduce lung mechanical function and innate immune defense in the absence of cellular toxicity.

PubMed

Botelho, Danielle J; Leo, Bey Fen; Massa, Christopher B; Sarkar, Srijata; Tetley, Terry D; Chung, Kian Fan; Chen, Shu; Ryan, Mary P; Porter, Alexandra E; Zhang, Junfeng; Schwander, Stephan K; Gow, Andrew J

2016-01-01

Multiple studies have examined the direct cellular toxicity of silver nanoparticles (AgNPs). However, the lung is a complex biological system with multiple cell types and a lipid-rich surface fluid; therefore, organ level responses may not depend on direct cellular toxicity. We hypothesized that interaction with the lung lining is a critical determinant of organ level responses. Here, we have examined the effects of low dose intratracheal instillation of AgNPs (0.05 μg/g body weight) 20 and 110 nm diameter in size, and functionalized with citrate or polyvinylpyrrolidone. Both size and functionalization were significant factors in particle aggregation and lipid interaction in vitro. One day post-intratracheal instillation lung function was assessed, and bronchoalveolar lavage (BAL) and lung tissue collected. There were no signs of overt inflammation. There was no change in surfactant protein-B content in the BAL but there was loss of surfactant protein-D with polyvinylpyrrolidone (PVP)-stabilized particles. Mechanical impedance data demonstrated a significant increase in pulmonary elastance as compared to control, greatest with 110 nm PVP-stabilized particles. Seven days post-instillation of PVP-stabilized particles increased BAL cell counts, and reduced lung function was observed. These changes resolved by 21 days. Hence, AgNP-mediated alterations in the lung lining and mechanical function resolve by 21 days. Larger particles and PVP stabilization produce the largest disruptions. These studies demonstrate that low dose AgNPs elicit deficits in both mechanical and innate immune defense function, suggesting that organ level toxicity should be considered.

A review of recent theoretical and computational studies on pinned surface nanobubbles

NASA Astrophysics Data System (ADS)

Liu, Yawei; Zhang, Xianren

2018-01-01

The findings of long-lived surface nanobubbles in various experiments brought a puzzle in theory, as they were supposed to be dissolved in microseconds due to the high Laplace pressure. However, an increasing number of studies suggest that the pinning of contact line, together with certain levels of oversaturation, is responsible for the anomalous stability of surface nanobubble. This mechanism can interpret most characteristics of surface nanobubbles. Here we summarize recent theoretical and computational work to explain how the surface nanobubbles become stable with the pinning of contact line. Other related work devoted to understand the unusual behaviors of pinned surface nanobubbles are also reviewed here.

A comparative study of stabilizing control of a planer electromagnetic levitation using PID and LQR controllers

NASA Astrophysics Data System (ADS)

Yaseen, Mundher H. A.

Magnetic levitation is a technique to suspend an object without any mechanical support. The main objective of this study is to demonstrate stabilized closed loop control of 1-DOF Maglev experimentally using real-time control simulink feature of (SIMLAB) microcontroller. Proportional Integral Derivative (PID) and Linear Quadratic Regulator (LQR) controllers are employed to examine the stability performance of the Maglev control system under effect of unbalanced change of load and wave signal on Maglev plane. The effect of unbalanced change of applied load on single point, line and plane are presented. Furthermore, in order to study the effect of sudden change in input signal, the input of wave signal has been applied on all points of the prototype maglev plate simultaneously. The results of pulse width modulation (PWM) reveal that the control system using LQR controller provides faster response to adjust the levitated plane comparing to PID controller. Moreover, the air gap distance that controlled using PID controller is rather stable with little oscillation. Meanwhile, LQR controller provided more stability and homogeneous response.

Nanobubbles in confined solution: Generation, contact angle, and stability.

PubMed

Wei, Jiachen; Zhang, Xianren; Song, Fan; Shao, Yingfeng

2018-02-14

The formation of gas bubbles presents a frequent challenge to microfluidic operations, for which fluids are geometrically confined to a microscale space. Here, to understand the mechanism of nucleating gas bubbles in microfluidic devices, we investigate the formation and stability of nanobubbles in confined solutions. Our molecular dynamics simulations show that while pinning of the contact line is a prerequisite for the stability of surface nanobubbles in open systems that can exchange gas with surrounding environment, in confined solutions, stable nanobubbles can exist even without pinning. In supersaturated condition, stable bubbles can be found in confined solutions with acute or obtuse contact angle, depending on the substrate hydrophobicity. We also demonstrate that when open to the bulk solution, the stable nanobubbles in closed systems would become unstable unless both supersaturation and pinning of the contact line are satisfied. Our results not only shed light on the design of novel heterogeneous surfaces for generating nanobubbles in confined space with controllable shape and stability but also address the crucial effect of gas exchange with the surroundings in determining the stability of nanobubbles.

Nanobubbles in confined solution: Generation, contact angle, and stability

NASA Astrophysics Data System (ADS)

Wei, Jiachen; Zhang, Xianren; Song, Fan; Shao, Yingfeng

2018-02-01

The formation of gas bubbles presents a frequent challenge to microfluidic operations, for which fluids are geometrically confined to a microscale space. Here, to understand the mechanism of nucleating gas bubbles in microfluidic devices, we investigate the formation and stability of nanobubbles in confined solutions. Our molecular dynamics simulations show that while pinning of the contact line is a prerequisite for the stability of surface nanobubbles in open systems that can exchange gas with surrounding environment, in confined solutions, stable nanobubbles can exist even without pinning. In supersaturated condition, stable bubbles can be found in confined solutions with acute or obtuse contact angle, depending on the substrate hydrophobicity. We also demonstrate that when open to the bulk solution, the stable nanobubbles in closed systems would become unstable unless both supersaturation and pinning of the contact line are satisfied. Our results not only shed light on the design of novel heterogeneous surfaces for generating nanobubbles in confined space with controllable shape and stability but also address the crucial effect of gas exchange with the surroundings in determining the stability of nanobubbles.

Microstructure of calcite deformed by high-pressure torsion: An X-ray line profile study

NASA Astrophysics Data System (ADS)

Schuster, Roman; Schafler, Erhard; Schell, Norbert; Kunz, Martin; Abart, Rainer

2017-11-01

Calcite aggregates were deformed to high strain using high-pressure torsion and applying confining pressures of 1-6 GPa and temperatures between room temperature and 450 °C. The run products were characterized by X-ray diffraction, and key microstructural parameters were extracted employing X-ray line profile analysis. The dominant slip system was determined as r { 10 1 bar 4 } ⟨ 2 bar 021 ⟩ with edge dislocation character. The resulting dislocation density and the size of the coherently scattering domains (CSD) exhibit a systematic dependence on the P-T conditions of deformation. While high pressure generally impedes recovery through reducing point defect mobility, the picture is complicated by pressure-induced phase transformations in the CaCO3 system. Transition from the calcite stability field to those of the high-pressure polymorphs CaCO3-II, CaCO3-III and CaCO3-IIIb leads to a change of the microstructural evolution with deformation. At 450 °C and pressures within the calcite stability field, dislocation densities and CSD sizes saturate at shear strains exceeding 10 in agreement with earlier studies at lower pressures. In the stability field of CaCO3-II, the dislocation density exhibits a more complex behavior. Furthermore, at a given strain and strain rate, the dislocation density increases and the CSD size decreases with increasing pressure within the stability fields of either calcite or of the high-pressure polymorphs. There is, however, a jump from high dislocation densities and small CSDs in the upper pressure region of the calcite stability field to lower dislocation densities and larger CSDs in the low-pressure region of the CaCO3-II stability field. This jump is more pronounced at higher temperatures and less so at room temperature. The pressure influence on the deformation-induced evolution of dislocation densities implies that pressure variations may change the rheology of carbonate rocks. In particular, a weakening is expected to occur at the transition from the calcite to the CaCO3-II stability field, if aragonite does not form.

First-principles studies of Te line-ordered alloys in a MoS2 monolayer

NASA Astrophysics Data System (ADS)

Andriambelaza, N. F.; Mapasha, R. E.; Chetty, N.

2018-04-01

The thermodynamic stability, structural and electronic properties of Te line-ordered alloys are investigated using density functional theory (DFT) methods. Thirty four possible Te line-ordered alloy configurations are found in a 5×5 supercell of a MoS2 monolayer. The calculated formation energies show that the Te line-ordered alloy configurations are thermodynamically stable at 0 K and agree very well with the random alloys. The lowest energy configurations at each concentration correspond to the configuration where the Te atom rows are far apart from each other (avoiding clustering) within the supercell. The variation of the lattice constant at different concentrations obey Vegard's law. The Te line-ordered alloys fine tune the band gap of a MoS2 monolayer although deviating from linearity behavior. Our results suggest that the Te line-ordered alloys can be an effective way to modulate the band gap of a MoS2 monolayer for nanoelectronic, optoelectronic and nanophotonic applications.

Telomere dynamics, end-to-end fusions and telomerase activation during the human fibroblast immortalization process.

PubMed

Ducray, C; Pommier, J P; Martins, L; Boussin, F D; Sabatier, L

1999-07-22

Loss of telomeric repeats during cell proliferation could play a role in senescence. It has been generally assumed that activation of telomerase prevents further telomere shortening and is essential for cell immortalization. In this study, we performed a detailed cytogenetic and molecular characterization of four SV40 transformed human fibroblastic cell lines by regularly monitoring the size distribution of terminal restriction fragments, telomerase activity and the associated chromosomal instability throughout immortalization. The mean TRF lengths progressively decreased in pre-crisis cells during the lifespan of the cultures. At crisis, telomeres reached a critical size, different among the cell lines, contributing to the peak of dicentric chromosomes, which resulted mostly from telomeric associations. We observed a direct correlation between short telomere length at crisis and chromosomal instability. In two immortal cell lines, although telomerase was detected, mean telomere length still continued to decrease whereas the number of dicentric chromosomes associated was stabilized. Thus telomerase could protect specifically telomeres which have reached a critical size against end-to-end dicentrics, while long telomeres continue to decrease, although at a slower rate as before crisis. This suggests a balance between elongation by telomerase and telomere shortening, towards a stabilized 'optimal' length.

Discrete-time stability of continuous-time controller designs for large space structures

NASA Technical Reports Server (NTRS)

Balas, M. J.

1982-01-01

In most of the stable control designs for flexible structures, continuous time is assumed. However, in view of the implementation of the controllers by on-line digital computers, the discrete-time stability of such controllers is an important consideration. In the case of direct-velocity feedback (DVFB), involving negative feedback from collocated force actuators and velocity sensors, it is not immediately apparent how much delay due to digital implementation of DVFB can be tolerated without loss of stability. The present investigation is concerned with such questions. A study is conducted of the discrete-time stability of DVFB, taking into account an employment of Euler's method of approximation of the time derivative. The obtained result gives an indication of the acceptable time-step size for stable digital implementation of DVFB. A result derived in connection with the consideration of the discrete-time stability of stable continuous-time systems provides a general condition under which digital implementation of such a system will remain stable.

Large-Signal Lyapunov-Based Stability Analysis of DC/AC Inverters and Inverter-Based Microgrids

NASA Astrophysics Data System (ADS)

Kabalan, Mahmoud

Microgrid stability studies have been largely based on small-signal linearization techniques. However, the validity and magnitude of the linearization domain is limited to small perturbations. Thus, there is a need to examine microgrids with large-signal nonlinear techniques to fully understand and examine their stability. Large-signal stability analysis can be accomplished by Lyapunov-based mathematical methods. These Lyapunov methods estimate the domain of asymptotic stability of the studied system. A survey of Lyapunov-based large-signal stability studies showed that few large-signal studies have been completed on either individual systems (dc/ac inverters, dc/dc rectifiers, etc.) or microgrids. The research presented in this thesis addresses the large-signal stability of droop-controlled dc/ac inverters and inverter-based microgrids. Dc/ac power electronic inverters allow microgrids to be technically feasible. Thus, as a prelude to examining the stability of microgrids, the research presented in Chapter 3 analyzes the stability of inverters. First, the 13 th order large-signal nonlinear model of a droop-controlled dc/ac inverter connected to an infinite bus is presented. The singular perturbation method is used to decompose the nonlinear model into 11th, 9th, 7th, 5th, 3rd and 1st order models. Each model ignores certain control or structural components of the full order model. The aim of the study is to understand the accuracy and validity of the reduced order models in replicating the performance of the full order nonlinear model. The performance of each model is studied in three different areas: time domain simulations, Lyapunov's indirect method and domain of attraction estimation. The work aims to present the best model to use in each of the three domains of study. Results show that certain reduced order models are capable of accurately reproducing the performance of the full order model while others can be used to gain insights into those three areas of study. This will enable future studies to save computational effort and produce the most accurate results according to the needs of the study being performed. Moreover, the effect of grid (line) impedance on the accuracy of droop control is explored using the 5th order model. Simulation results show that traditional droop control is valid up to R/X line impedance value of 2. Furthermore, the 3rd order nonlinear model improves the currently available inverter-infinite bus models by accounting for grid impedance, active power-frequency droop and reactive power-voltage droop. Results show the 3rd order model's ability to account for voltage and reactive power changes during a transient event. Finally, the large-signal Lyapunov-based stability analysis is completed for a 3 bus microgrid system (made up of 2 inverters and 1 linear load). The thesis provides a systematic state space large-signal nonlinear mathematical modeling method of inverter-based microgrids. The inverters include the dc-side dynamics associated with dc sources. The mathematical model is then used to estimate the domain of asymptotic stability of the 3 bus microgrid. The three bus microgrid system was used as a case study to highlight the design and optimization capability of a large-signal-based approach. The study explores the effect of system component sizing, load transient and generation variations on the asymptotic stability of the microgrid. Essentially, this advancement gives microgrid designers and engineers the ability to manipulate the domain of asymptotic stability depending on performance requirements. Especially important, this research was able to couple the domain of asymptotic stability of the ac microgrid with that of the dc side voltage source. Time domain simulations were used to demonstrate the mathematical nonlinear analysis results.

Combined line-of-sight error and angular position to generate feedforward control for a charge-coupled device-based tracking loop

NASA Astrophysics Data System (ADS)

Tang, Tao; Cai, Huaxiang; Huang, Yongmei; Ren, Ge

2015-10-01

A feedforward control based on data fusion is proposed to enhance closed-loop performance. The target trajectory as the observed value of a Kalman filter is recovered by synthesizing line-of-sight error and angular position from the encoder. A Kalman filter based on a Singer acceleration model is employed to estimate the target velocity. In this control scheme, the control stability is influenced by the bandwidth of the Kalman filter and time misalignment. The transfer function of the Kalman filter in the frequency domain is built for analyzing the closed loop stability, which shows that the Kalman filter is the major factor that affects the control stability. The feedforward control proposed here is verified through simulations and experiments.

Optimal line drop compensation parameters under multi-operating conditions

NASA Astrophysics Data System (ADS)

Wan, Yuan; Li, Hang; Wang, Kai; He, Zhe

2017-01-01

Line Drop Compensation (LDC) is a main function of Reactive Current Compensation (RCC) which is developed to improve voltage stability. While LDC has benefit to voltage, it may deteriorate the small-disturbance rotor angle stability of power system. In present paper, an intelligent algorithm which is combined by Genetic Algorithm (GA) and Backpropagation Neural Network (BPNN) is proposed to optimize parameters of LDC. The objective function proposed in present paper takes consideration of voltage deviation and power system oscillation minimal damping ratio under multi-operating conditions. A simulation based on middle area of Jiangxi province power system is used to demonstrate the intelligent algorithm. The optimization result shows that coordinate optimized parameters can meet the multioperating conditions requirement and improve voltage stability as much as possible while guaranteeing enough damping ratio.

Line-Tension Controlled Mechanism for Influenza Fusion

PubMed Central

Risselada, Herre Jelger; Smirnova, Yuliya G.; Grubmüller, Helmut; Marrink, Siewert Jan; Müller, Marcus

2012-01-01

Our molecular simulations reveal that wild-type influenza fusion peptides are able to stabilize a highly fusogenic pre-fusion structure, i.e. a peptide bundle formed by four or more trans-membrane arranged fusion peptides. We rationalize that the lipid rim around such bundle has a non-vanishing rim energy (line-tension), which is essential to (i) stabilize the initial contact point between the fusing bilayers, i.e. the stalk, and (ii) drive its subsequent evolution. Such line-tension controlled fusion event does not proceed along the hypothesized standard stalk-hemifusion pathway. In modeled influenza fusion, single point mutations in the influenza fusion peptide either completely inhibit fusion (mutants G1V and W14A) or, intriguingly, specifically arrest fusion at a hemifusion state (mutant G1S). Our simulations demonstrate that, within a line-tension controlled fusion mechanism, these known point mutations either completely inhibit fusion by impairing the peptide’s ability to stabilize the required peptide bundle (G1V and W14A) or stabilize a persistent bundle that leads to a kinetically trapped hemifusion state (G1S). In addition, our results further suggest that the recently discovered leaky fusion mutant G13A, which is known to facilitate a pronounced leakage of the target membrane prior to lipid mixing, reduces the membrane integrity by forming a ‘super’ bundle. Our simulations offer a new interpretation for a number of experimentally observed features of the fusion reaction mediated by the prototypical fusion protein, influenza hemagglutinin, and might bring new insights into mechanisms of other viral fusion reactions. PMID:22761674

An extended macro model accounting for acceleration changes with memory and numerical tests

NASA Astrophysics Data System (ADS)

Cheng, Rongjun; Ge, Hongxia; Sun, Fengxin; Wang, Jufeng

2018-09-01

Considering effect of acceleration changes with memory, an improved continuum model of traffic flow is proposed in this paper. By applying the linear stability theory, we derived the new model's linear stability condition. Through nonlinear analysis, the KdV-Burgers equation is derived to describe the propagating behavior of traffic density wave near the neutral stability line. Numerical simulation is carried out to study the extended traffic flow model, which explores how acceleration changes with memory affected each car's velocity, density and fuel consumption and exhaust emissions. Numerical results demonstrate that acceleration changes with memory have significant negative effect on dynamic characteristic of traffic flow. Furthermore, research results verify that the effect of acceleration changes with memory will deteriorate the stability of traffic flow and increase cars' total fuel consumptions and emissions during the whole evolution of small perturbation.

Nonlinear analysis of an improved continuum model considering headway change with memory

NASA Astrophysics Data System (ADS)

Cheng, Rongjun; Wang, Jufeng; Ge, Hongxia; Li, Zhipeng

2018-01-01

Considering the effect of headway changes with memory, an improved continuum model of traffic flow is proposed in this paper. By means of linear stability theory, the new model’s linear stability with the effect of headway changes with memory is obtained. Through nonlinear analysis, the KdV-Burgers equation is derived to describe the propagating behavior of traffic density wave near the neutral stability line. Numerical simulation is carried out to study the improved traffic flow model, which explores how the headway changes with memory affected each car’s velocity, density and energy consumption. Numerical results show that when considering the effects of headway changes with memory, the traffic jams can be suppressed efficiently. Furthermore, research results demonstrate that the effect of headway changes with memory can avoid the disadvantage of historical information, which will improve the stability of traffic flow and minimize car energy consumption.

Plasma stable, pH-sensitive fusogenic polymer-modified liposomes: A promising carrier for mitoxantrone.

PubMed

Ghanbarzadeh, Saeed; Arami, Sanam; Pourmoazzen, Zhaleh; Ghasemian-Yadegari, Javad; Khorrami, Arash

2014-07-01

pH-sensitive liposomes are designed to undergo acid-triggered destabilization. In the present study, we prepared polymer-modified, plasma stable, pH-sensitive fusogenic mitoxantrone liposomes to increase efficacy and selectivity on cancer cell lines. Conventional liposomes were prepared using cholesterol and dipalmitoyl-sn-glycero-3-phosphatidylethanolamine. Dioleoylphosphatidylethanolamine and a cholesteryl derivative, poly(monomethylitaconate)-co-poly(N,N-dimethylaminoethyl methacrylate) (PMMI-co-PDMAEMA), were used for the preparation of pH-sensitive fusogenic liposomes. Using polyethylene glycol (PEG)-poly(monomethylitaconate)-CholC6 (PEG-PMMI-CholC6) copolymers instead of cholesterol introduced pH-sensitive and plasma stability properties simultaneously in prepared liposomes. All formulations were prepared by thin film hydration method and subsequently, pH-sensitivity and stability in human serum were evaluated. The ability of pH-sensitive fusogenic liposomes to enhance the mitoxantrone cytotoxicity and selectivity in cancerous cell lines was assessed in vitro compared to normal cell line using human breast cancer cell line (MCF-7), human prostate cancer cell line (PC-3), and human umbilical vein endothelial cells line. Results revealed that both PMMI-co-PDMAEMA and PEG-PMMI-CholC6-based formulations showed pH-sensitive property and were found to rapidly release mitoxantrone under mildly acidic conditions. Nevertheless, only the PEG-PMMI-CholC6-based liposomes preserved pH-sensitivity after incubation in plasma. Mitoxantrone loaded-pH-sensitive fusogenic liposomes exhibited a higher cytotoxicity than the control conventional liposomes on MCF-7 and PC-3 cell lines. On the contrary, both pH-sensitive fusogenic liposomes showed lower cytotoxic effect on human umbilical vein endothelial cell line. Plasma stable, pH-sensitive fusogenic liposomes are promising carriers for enhancing the efficiency and selectivity, besides reduction of the side effects of anticancer agents. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Evaluation of conditions along the grounding line of temperate marine glaciers: An example from Muir Inlet, Glacier Bay, Alaska

USGS Publications Warehouse

Seramur, K.C.; Powell, R.D.; Carlson, P.R.

1997-01-01

In the marine environment, stability of the glacier terminus and the location of subglacial streams are the dominant controls on the distribution of grounding-line deposits within morainal banks. A morainal bank complex in Muir Inlet, Glacier Bay, SE Alaska, is used to develop a model of terminus stability and location of subglacial streams along the grounding line of temperate marine glaciers. This model can be used to interpret former grounding-line conditions in other glacimarine settings from the facies architecture within morainal bank deposits. The Muir Inlet morainal bank complex was deposited between 1860 A.D. and 1899 A.D., and historical observations provide a record of terminus positions, glacial retreat rates and sedimentary sources. These data are used to reconstruct the depositional environment and to develop a correlation between sedimentary facies and conditions along the grounding line. Four seismic facies identified on the high-resolution seismic-reflection profiles are used to interpret sedimentary facies within the morainal bank complex. Terminus stability is interpreted from the distribution of sedimentary facies within three distinct submarine geomorphic features, a grounding-line fan; stratified ridges, and a field of push ridges. The grounding-line fan was deposited along a stable terminus and is represented on seismic-reflection profiles by two distinct seismic facies, a proximal and a distal fan facies. The proximal fan facies was deposited at the efflux of subglacial streams and indicates the location of former glacifluvial discharges into the sea. Stratified ridges formed as a result of the influence of a quasi-stable terminus on the distribution of sedimentary facies along the grounding line. A field of push ridges formed along the grounding line of an unstable terminus that completely reworked the grounding-line deposits through glacitectonic deformation. Between 1860 A.D. and 1899 A.D. (39 years), 8.96 x 108 m3 of sediment were deposited within the Muir Inlet morainal bank complex at an average annual sediment accumulation rate of 2.3 x 107 m3/a. This rate represents the annual sediment production capacity of the glacier when the Muir Inlet drainage basin is filled with glacial ice.

Regulation of cyclooxygenase-2 expression by cAMP response element and mRNA stability in a human airway epithelial cell line exposed to zinc

EPA Science Inventory

Exposure to zinc-laden particulate matter in ambient and occupational settings has been associated with proinflammatory responses in the lung. Cyclooxygenase 2-derived eicosanoids are important modulators of airway inflammation. In this study, we characterized the transcriptional...

Subsurface Characterization using Geophysical Seismic Refraction Survey for Slope Stabilization Design with Soil Nailing

NASA Astrophysics Data System (ADS)

Ashraf Mohamad Ismail, Mohd; Ng, Soon Min; Hazreek Zainal Abidin, Mohd; Madun, Aziman

2018-04-01

The application of geophysical seismic refraction for slope stabilization design using soil nailing method was demonstrated in this study. The potential weak layer of the study area is first identify prior to determining the appropriate length and location of the soil nail. A total of 7 seismic refraction survey lines were conducted at the study area with standard procedures. The refraction data were then analyzed by using the Pickwin and Plotrefa computer software package to obtain the seismic velocity profiles distribution. These results were correlated with the complementary borehole data to interpret the subsurface profile of the study area. It has been identified that layer 1 to 3 is the potential weak zone susceptible to slope failure. Hence, soil nails should be installed to transfer the tensile load from the less stable layer 3 to the more stable layer 4. The soil-nail interaction will provide a reinforcing action to the soil mass thereby increasing the stability of the slope.

A New Water-Soluble Nanomicelle Formed through Self-Assembly of Pectin-Curcumin Conjugates: Preparation, Characterization, and Anticancer Activity Evaluation.

PubMed

Bai, Feng; Diao, Jiajing; Wang, Ying; Sun, Shixin; Zhang, Hongmei; Liu, Yunyun; Wang, Yanqing; Cao, Jian

2017-08-16

Curcumin is a dominating active component of Curcuma longa and has been studied widely because of its prominent biological activities. The extremely low aqueous solubility, stability, and bioavailability of curcumin limit its application in the field of medicine. In this study, we developed pectin-curcumin (PEC-CCM) conjugates that could self-assemble water-soluble nanomicelles in aqueous solution. The structure of PEC-CCM conjugates was characterized by ultraviolet-visible spectra, fluorescence spectra, Fourier transform infrared spectroscopy, and 1 H nuclear magnetic resonance spectroscopy. The thermal property of PEC-CCM conjugates was investigated by thermogravimetric analysis. It was found that PEC-CCM conjugates had formed nanomicelles in aqueous medium via self-assembly. These nanomicelles were observed as small spheres or ellipsoids and aggregated with a size range of 70-190 nm by transmission electron microscopy analysis. In a solution of nanomicelles, the stability of curcumin was improved, and its antioxidant property was preserved. The anticancer activity of PEC-CCM conjugates was quantified by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay using a hepatic cancer cell line (HepG2), a breast cancer cell line (MCF-7), a cervical cancer cell line (HeLa), and a human normal kidney cell line (293A). It was found that the curcumin of PEC-CCM conjugates had a more significant inhibitory effect on cancer cells and was less cytotoxic to normal cells than free curcumin was. PEC-CCM conjugates have great potential for some food and pharmaceutical applications.

Human ESCs predisposition to karyotypic instability: Is a matter of culture adaptation or differential vulnerability among hESC lines due to inherent properties?

PubMed

Catalina, Puri; Montes, Rosa; Ligero, Gertru; Sanchez, Laura; de la Cueva, Teresa; Bueno, Clara; Leone, Paola E; Menendez, Pablo

2008-10-03

The use of human embryonic stem cells (hESCs) in research is increasing and hESCs hold the promise for many biological, clinical and toxicological studies. Human ESCs are expected to be chromosomally stable since karyotypic changes represent a pitfall for potential future applications. Recently, several studies have analysed the genomic stability of several hESC lines maintained after prolonged in vitro culture but controversial data has been reported. Here, we prompted to compare the chromosomal stability of three hESC lines maintained in the same laboratory using identical culture conditions and passaging methods. Molecular cytogenetic analyses performed in three different hESC lines maintained in parallel in identical culture conditions revealed significant differences among them in regard to their chromosomal integrity. In feeders, the HS181, SHEF-1 and SHEF-3 hESC lines were chromosomally stable up to 185 passages using either mechanical or enzymatic dissection methods. Despite the three hESC lines were maintained under identical conditions, each hESC line behaved differently upon being transferred to a feeder-free culture system. The two younger hESC lines, HS181 (71 passages) and SHEF-3 (51 passages) became chromosomally unstable shortly after being cultured in feeder-free conditions. The HS181 line gained a chromosome 12 by passage 17 and a marker by passage 21, characterized as a gain of chromosome 20 by SKY. Importantly, the mosaicism for trisomy 12 gradually increased up to 89% by passage 30, suggesting that this karyotypic abnormality provides a selective advantage. Similarly, the SHEF-3 line also acquired a trisomy of chromosome 14 as early as passage 10. However, this karyotypic aberration did not confer selective advantage to the genetically abnormal cells within the bulk culture and the level of mosaicism for the trisomy 14 remained overtime between 15%-36%. Strikingly, however, a much older hESC line, SHEF-1, which was maintained for 185 passages in feeders did not undergo any numerical or structural chromosomal change after 30 passages in feeder-free culture and over 215 passages in total. These results support the concept that feeder-free conditions may partially contribute to hESC chromosomal changes but also confirm the hypothesis that regardless of the culture conditions, culture duration or splitting methods, some hESC lines are inherently more prone than others to karyotypic instability.

Relevant parameter space and stability of spherical tokamaks with a plasma center column

NASA Astrophysics Data System (ADS)

Lampugnani, L. G.; Garcia-Martinez, P. L.; Farengo, R.

2017-02-01

A spherical tokamak (ST) with a plasma center column (PCC) can be formed inside a simply connected chamber via driven magnetic relaxation. From a practical perspective, the ST-PCC could overcome many difficulties associated with the material center column of the standard ST reactor design. Besides, the ST-PCC concept can be regarded as an advanced helicity injected device that would enable novel experiments on the key physics of magnetic relaxation and reconnection. This is because the concept includes not only a PCC but also a coaxial helicity injector (CHI). This combination implies an improved level of flexibility in the helicity injection scheme required for the formation and sustainment phases. In this work, the parameter space determining the magnetic structure of the ST-PCC equilibria is studied under the assumption of fully relaxed plasmas. In particular, it is shown that the effect of the external bias field of the PCC and the CHI essentially depends on a single parameter that measures the relative amount of flux of these two entities. The effect of plasma elongation on the safety factor profile and the stability to the tilt mode are also analyzed. In the first part of this work, the stability of the system is explained in terms of the minimum energy principle, and relevant stability maps are constructed. While this picture provides an adequate insight into the underlying physics of the instability, it does not include the stabilizing effect of line-tying at the electrodes. In the second part, a dynamical stability analysis of the ST-PCC configurations, including the effect of line-tying, is performed by numerically solving the magnetohydrodynamic equations. A significant stability enhancement is observed when the PCC contains more than the 70% of the total external bias flux, and the elongation is not higher than two.

Performance prediction of optical image stabilizer using SVM for shaker-free production line

NASA Astrophysics Data System (ADS)

Kim, HyungKwan; Lee, JungHyun; Hyun, JinWook; Lim, Haekeun; Kim, GyuYeol; Moon, HyukSoo

2016-04-01

Recent smartphones adapt the camera module with optical image stabilizer(OIS) to enhance imaging quality in handshaking conditions. However, compared to the non-OIS camera module, the cost for implementing the OIS module is still high. One reason is that the production line for the OIS camera module requires a highly precise shaker table in final test process, which increases the unit cost of the production. In this paper, we propose a framework for the OIS quality prediction that is trained with the support vector machine and following module characterizing features : noise spectral density of gyroscope, optically measured linearity and cross-axis movement of hall and actuator. The classifier was tested on an actual production line and resulted in 88% accuracy of recall rate.

Application of long-term simulation programs for analysis of system islanding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sancha, J.L.; Llorens, M.L.; Moreno, J.M.

1997-02-01

This paper describes the main results and conclusions from the application of two different long-term stability programs to the analysis of a system islanding scenario for a study case developed by Red Electrica de Espana (REE), based on the Spanish system. Two main goals were to evaluate the performance of both the influence of some important control and protection elements (tie-line loss-of-synchronism relays, underfrequency load-shedding, load-frequency control, and power plant dynamics). Conclusions about modeling and computational requirements for system islanding (frequency) scenarios and use of long-term stability programs are presented.

Stability of stationary solutions for inflow problem on the micropolar fluid model

NASA Astrophysics Data System (ADS)

Yin, Haiyan

2017-04-01

In this paper, we study the asymptotic behavior of solutions to the initial boundary value problem for the micropolar fluid model in a half-line R+:=(0,∞). We prove that the corresponding stationary solutions of the small amplitude to the inflow problem for the micropolar fluid model are time asymptotically stable under small H1 perturbations in both the subsonic and degenerate cases. The microrotation velocity brings us some additional troubles compared with Navier-Stokes equations in the absence of the microrotation velocity. The proof of asymptotic stability is based on the basic energy method.

Stability limits for the supercooled liquid and superheated crystal of Lennard-Jones particles

NASA Astrophysics Data System (ADS)

Loscar, Ernesto S.; Martin, Daniel A.; Grigera, Tomás S.

2017-07-01

We have studied the limits of stability in the first order liquid-solid phase transition in a Lennard-Jones system by means of the short-time relaxation method and using the bond-orientational order parameter Q6. These limits are compared with the melting line. We have paid special attention to the supercooled liquid, comparing our results with the point where the free energy cost of forming a nucleating droplet goes to zero. We also indirectly estimate the dimension associated to the critical nucleus at the spinodal, expected to be fractal according to mean field theories of nucleation.

Sensitivity analysis of hydrodynamic stability operators

NASA Technical Reports Server (NTRS)

Schmid, Peter J.; Henningson, Dan S.; Khorrami, Mehdi R.; Malik, Mujeeb R.

1992-01-01

The eigenvalue sensitivity for hydrodynamic stability operators is investigated. Classical matrix perturbation techniques as well as the concept of epsilon-pseudoeigenvalues are applied to show that parts of the spectrum are highly sensitive to small perturbations. Applications are drawn from incompressible plane Couette, trailing line vortex flow and compressible Blasius boundary layer flow. Parametric studies indicate a monotonically increasing effect of the Reynolds number on the sensitivity. The phenomenon of eigenvalue sensitivity is due to the non-normality of the operators and their discrete matrix analogs and may be associated with large transient growth of the corresponding initial value problem.

Postural Stability is Altered by Blood Shift

NASA Astrophysics Data System (ADS)

Marais, M.; Denise, P.; Guincetre, J. Y.; Normand, H.

2008-06-01

Non-vestibular influences as shift in blood volume changed perception of body posture. Then, factors affecting blood shift may alter postural control. The purpose of our study was to investigate the effects of leg venous contention on postural stability. Twelve subjects were studied on a balance plate for 5 minutes with the eyes closed, in 3 conditions: with no leg venous contention or grade 1 and 3 support stockings. Standard deviation of x and y position was calculated before and after the closure of the eyes. Strong venous contention altered postural stability, after the eyes were closed, during the first 10 s of standing. As support stockings prevent blood shift induced by upright posture, this result is in line with the hypothesis that blood shifts influence the perception of body orientation and postural control among others factors as vision, vestibular inputs... This strong venous contention could induce an increase of fall.

Effects of Phasor Measurement Uncertainty on Power Line Outage Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chen; Wang, Jianhui; Zhu, Hao

2014-12-01

Phasor measurement unit (PMU) technology provides an effective tool to enhance the wide-area monitoring systems (WAMSs) in power grids. Although extensive studies have been conducted to develop several PMU applications in power systems (e.g., state estimation, oscillation detection and control, voltage stability analysis, and line outage detection), the uncertainty aspects of PMUs have not been adequately investigated. This paper focuses on quantifying the impact of PMU uncertainty on power line outage detection and identification, in which a limited number of PMUs installed at a subset of buses are utilized to detect and identify the line outage events. Specifically, the linemore » outage detection problem is formulated as a multi-hypothesis test, and a general Bayesian criterion is used for the detection procedure, in which the PMU uncertainty is analytically characterized. We further apply the minimum detection error criterion for the multi-hypothesis test and derive the expected detection error probability in terms of PMU uncertainty. The framework proposed provides fundamental guidance for quantifying the effects of PMU uncertainty on power line outage detection. Case studies are provided to validate our analysis and show how PMU uncertainty influences power line outage detection.« less

Oestradiol reduces Liver Receptor Homolog-1 mRNA transcript stability in breast cancer cell lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazarus, Kyren A.; Environmental and Biotechnology Centre, Swinburne University, Hawthorn, Victoria 3122; Zhao, Zhe

2013-08-30

Highlights: •LRH-1 is an orphan nuclear receptor that regulates tumor proliferation. •In breast cancer, high mRNA expression is associated with ER+ status. •In ER−ve cells, despite very low mRNA, we found abundant LRH-1 protein. •Our data show distinctly different LRH-1 protein isoforms in ER− and ER+ breast cancer cells. •This is due to differences in LRH-1 mRNA and protein stability rates. -- Abstract: The expression of orphan nuclear receptor Liver Receptor Homolog-1 (LRH-1) is elevated in breast cancer and promotes proliferation, migration and invasion in vitro. LRH-1 expression is regulated by oestrogen (E{sub 2}), with LRH-1 mRNA transcript levels highermore » in oestrogen receptor α (ERα) positive (ER+) breast cancer cells compared to ER− cells. However, the presence of LRH-1 protein in ER− cells suggests discordance between mRNA transcript levels and protein expression. To understand this, we investigated the impact of mRNA and protein stability in determining LRH-1 protein levels in breast cancer cells. LRH-1 transcript levels were significantly higher in ER+ versus ER− breast cancer cells lines; however LRH-1 protein was expressed at similar levels. We found LRH-1 mRNA and protein was more stable in ER− compared to ER+ cell lines. The tumor-specific LRH-1 variant isoform, LRH-1v4, which is highly responsive to E{sub 2}, showed increased mRNA stability in ER− versus ER+ cells. In addition, in MCF-7 and T47-D cell lines, LRH-1 total mRNA stability was reduced with E{sub 2} treatment, this effect mediated by ERα. Our data demonstrates that in ER− cells, increased mRNA and protein stability contribute to the abundant protein expression levels. Expression and immunolocalisation of LRH-1 in ER− cells as well as ER− tumors suggests a possible role in the development of ER− tumors. The modulation of LRH-1 bioactivity may therefore be beneficial as a treatment option in both ER− and ER+ breast cancer.« less

First-line nurse managers in university hospitals--captives to their own professional culture?

PubMed

Viitanen, Elina; Wiili-Peltola, Erja; Tampsi-Jarvala, Tiina; Lehto, Juhani

2007-01-01

This study investigates whether first-line nurse managers in hospitals share common dispositions related to managerial work and leadership, what they are like, and what their relationship is with the various expectations set on them. The first data were collected by focus group interviews in the autumn of 2000 and analysed using qualitative content analysis and frame analysis. The second data set were part of a questionnaire survey addressed to the same managers in 2001 with a focus on their diverse leadership roles. Among first-line nurse managers, the management frameworks of a nurturing mother and an administrative nurse displayed the strongest prominence, and the emphasis seemed to be evolving towards the administrative. The results from the survey confirmed the findings of this study in relation to first-line nurse managers' management frameworks. The line of development found in this study may add to the permanence of operations and the stability of the operative culture at a university hospital. It may also diminish the opportunities for nursing development in university hospital wards and weaken the potential for a new kind of competence among both managers and their subordinates.

Multiwavelength fiber laser

NASA Astrophysics Data System (ADS)

Das, Goutam

This thesis studies experimentally and theoretically a few designs of multiwavelength fiber lasers. Four different configurations are proposed and demonstrated; all of which can operate at room temperatures. An elliptical core erbium-doped fiber is used as the gain medium, which is single mode along the minor axis and multimode along the major axis. The principle of operation is based on the anisotropic gain effect of an elliptical core erbium-doped fiber. Stable multiwavelength operation is achieved at room temperatures. A polarization controller is used to control and select the lasing wavelengths. The stability of the lasing lines, in the presence of anisotropic gain effects, has been examined. The maximum number of stable lasing lines that may be obtained depends on the number of modes supported by the erbium-doped fiber. The effects of the dimensions of the fiber are also studied. A ring resonator is formed using an elliptical core erbium-doped fiber. The basic theoretical expression for the threshold pump power for each lasing line is developed. The theoretical results are in excellent agreement with the values obtained experimentally. The dependence of the separations between the lasing wavelengths on the dimensions of the erbium-doped fiber is examined. A theoretical study of a Sagnac loop interferometer and its applications in a passive ring resonator is reported. A ring resonator is formed by using the Sagnac loop filter in the cavity. The experimental results show that the separations between the lasing wavelengths may be controlled by adjusting the birefringence of the Sagnac loop interferometer. These experimental results agree with the theoretical findings. Similarly, another resonator is formed using a Sagnac loop reflector and a broadband reflector in a Fabry-Perot configuration. An optical switch is made, where two wavelengths may be switched by using a polarization controller in the cavity. To study the stability of the lasing wavelengths, the outputs of the lasers are monitored for a few hours using an optical spectrum analyzer with a resolution bandwidth of 0.06 nm. The experimental results show that intensity fluctuations of the lasing lines of less than 0.2 dB are possible with no changes in wavelength. High concentrations of erbium in the fiber degrade the stability of the lasing wavelengths resulting in greater intensity fluctuations. The lasers may be made to lase in the C band or L band by adjusting the length of the erbium-doped fiber in the cavity.

Production of higher quality bio-oils by in-line esterification of pyrolysis vapor

DOEpatents

Hilten, Roger Norris; Das, Keshav; Kastner, James R; Bibens, Brian P

2014-12-02

The disclosure encompasses in-line reactive condensation processes via vapor phase esterification of bio-oil to decease reactive species concentration and water content in the oily phase of a two-phase oil, thereby increasing storage stability and heating value. Esterification of the bio-oil vapor occurs via the vapor phase contact and subsequent reaction of organic acids with ethanol during condensation results in the production of water and esters. The pyrolysis oil product can have an increased ester content and an increased stability when compared to a condensed pyrolysis oil product not treated with an atomized alcohol.

Delocalized periodic vibrations in nonlinear LC and LCR electrical chains

NASA Astrophysics Data System (ADS)

Chechin, G. M.; Shcherbinin, S. A.

2015-05-01

We consider electrical LC- and LCR-chains consisting of N cells. In the LC-chain each cell contains a linear inductor L and a nonlinear capacitor C, while the cell in the LCR-chain include additionally a resistor R and an voltage source. It is assumed that voltage dependence of capacitors represents an even function. Such capacitors have implemented by some experimental groups studying propagation of electrical signals in the lines constructed on MOS and CMOS substrates. In these chains, we study dynamical regimes representing nonlinear normal modes (NNMs) by Rosenberg. We prove that maximum possible number of symmetry-determined NNMs which can be excited in the considered chains is equal to 5. The stability of these modes for different N is studied with the aid of the group-theoretical method [Physical Review E 73 (2006) 36216] which allows to simplify radically the variational systems appearing in the Floquet stability analysis. For NNMs in LC-chain, the scaling of the voltage stability threshold in the thermodynamic limit (N → ∞) is determined. It is shown that the above group theoretical method can be also used for studying stability of NNMs in the LCR-chains.

Longitudinal Stability and Control Characteristics from a Flight Investigation of a Cruciform Canard Missile Configuration Having an Exposed Wing-canard Area Ratio of 16:1

NASA Technical Reports Server (NTRS)

Moul, Martin T; Wineman, Andrew R

1952-01-01

A flight investigation has been made to determine the longitudinal stability and control characteristics of a 60 0 delta-wing-canard missile configuration with an exposed wing-canard area ratio of 16:1. The results presented include the longitudinal stability derivatives, control effectiveness, and drag characteristics for a Mach number range of 0.75 to 1.80 and are compared with the results of a similar configuration having larger 6ontrols. Stability characteristics are also presented from the flights of an interdigitated canard configuration at a Mach number of 2.08 and a wing-body configuration at Mach numbers of 1.25 to 1.45. The stability derivatives varied gradually with Mach number with the exception of the damping-in-pitch derivative. Aerodynamic damping in pitch decreased to a minimum at a Mach number of 1.0 3, then increased to a peak value at a Mach number of 1.26 followed by a gradual decrease at higher Mach numbers. The aerodynamic-center location of the in-line canard configuration shifted rearward 13 percent of the mean aerodynamic chord at transonic speeds. The pitching-moment curve slope was 25 percent greater for the model having no canards than for the in-line configuration. No large effects of interdigitation were noted in the stability derivatives. Pitching effectiveness of the in-line configuration was maintained throughout the Mach number range. A comparison of the stability and control characteristics of two canard configurations having different area controls showed that decreasing the control area 44 percent decreased the pitching effectiveness proportionally, shifted the aerodynamic-center location rearward 9 to 14 percent of the mean aerodynamic chord, and reduced the total hinge moments required for 10 trimmed flight about 50 percent at transonic speeds.

One- and two-stage Arrhenius models for pharmaceutical shelf life prediction.

PubMed

Fan, Zhewen; Zhang, Lanju

2015-01-01

One of the most challenging aspects of the pharmaceutical development is the demonstration and estimation of chemical stability. It is imperative that pharmaceutical products be stable for two or more years. Long-term stability studies are required to support such shelf life claim at registration. However, during drug development to facilitate formulation and dosage form selection, an accelerated stability study with stressed storage condition is preferred to quickly obtain a good prediction of shelf life under ambient storage conditions. Such a prediction typically uses Arrhenius equation that describes relationship between degradation rate and temperature (and humidity). Existing methods usually rely on the assumption of normality of the errors. In addition, shelf life projection is usually based on confidence band of a regression line. However, the coverage probability of a method is often overlooked or under-reported. In this paper, we introduce two nonparametric bootstrap procedures for shelf life estimation based on accelerated stability testing, and compare them with a one-stage nonlinear Arrhenius prediction model. Our simulation results demonstrate that one-stage nonlinear Arrhenius method has significant lower coverage than nominal levels. Our bootstrap method gave better coverage and led to a shelf life prediction closer to that based on long-term stability data.

δ-Catenin Increases the Stability of EGFR by Decreasing c-Cbl Interaction and Enhances EGFR/Erk1/2 Signaling in Prostate Cancer.

PubMed

Shrestha, Nensi; Shrestha, Hridaya; Ryu, Taeyong; Kim, Hangun; Simkhada, Shishli; Cho, Young-Chang; Park, So-Yeon; Cho, Sayeon; Lee, Kwang-Youl; Lee, Jae-Hyuk; Kim, Kwonseop

2018-04-30

δ-Catenin, a member of the p120-catenin subfamily of armadillo proteins, reportedly increases during the late stage of prostate cancer. Our previous study demonstrates that δ-catenin increases the stability of EGFR in prostate cancer cell lines. However, the molecular mechanism behind δ-catenin-mediated enhanced stability of EGFR was not explored. In this study, we hypothesized that δ-catenin enhances the protein stability of EGFR by inhibiting its lysosomal degradation that is mediated by c-casitas b-lineage lymphoma (c-Cbl), a RING domain E3 ligase. c-Cbl monoubiquitinates EGFR and thus facilitates its internalization, followed by lysosomal degradation. We observed that δ-catenin plays a key role in EGFR stability and downstream signaling. δ-Catenin competes with c-Cbl for EGFR binding, which results in a reduction of binding between c-Cbl and EGFR and thus decreases the ubiquitination of EGFR. This in turn increases the expression of membrane bound EGFR and enhances EGFR/Erk1/2 signaling. Our findings add a new perspective on the role of δ-catenin in enhancing EGFR/Erk1/2 signaling-mediated prostate cancer.

Progress on the Surface Nanobubble Story: What is in the bubble? Why does it exist?

PubMed

Peng, Hong; Birkett, Greg R; Nguyen, Anh V

2015-08-01

Interfaces between aqueous solutions and hydrophobic solid surfaces are important in various areas of science and technology. Many researchers have found that forces between hydrophobic surfaces in aqueous solution are significantly different from the classical DLVO theory. Long-range attractive forces (non-DLVO forces) are thought to be affected by nanoscopic gaseous domains at the interfaces. This is a review of the latest research on nanobubbles at hydrophobic surfaces from experimental and simulation studies. The review focusses on non-intrusive optical view of surface nanobubbles and gas enrichment on solid surfaces by imaging and force mapping. By use of these recent experimental data in conjunction with molecular simulation work, all major theories on surface nanobubble formation and stability are critically reviewed. Even though the current body of research cannot comprehensively explain all properties of surface nanobubbles observed, the fundamental understanding has been significantly improved. Line tension has been shown to be incapable of explaining the contact angle of nanobubbles. Dense gas layer theory provides a new explanation on both large contact angle and long-time stability. The high density of gas in these domains may significantly affect the gas-water interface which is in line with some observation made on bulk nanobubbles. Along this line of inquiry, experimental and simulation effort should be focussed on measuring the density within surface nanobubbles and the properties of the gas water interface which may be the key to explaining the stability of these nanobubbles. Copyright © 2014 Elsevier B.V. All rights reserved.

Stability and broad-sense heritaibility of mineral content in potato: copper and sulfur

USDA-ARS?s Scientific Manuscript database

Potato breeding lines and varieties in two separate trials were evaluated for copper and sulfur content by wet ashing and Inductively Coupled Argon Plasma Emission Spectrophotometer analysis. Stability and broad-sense heritability were determined. Copper contents ranged among genotypes between 2.0...

Attitude dynamic of spin-stabilized satellites with flexible appendages

NASA Technical Reports Server (NTRS)

Renard, M. L.

1973-01-01

Equations of motion and computer programs have been developed for analyzing the motion of a spin-stabilized spacecraft having long, flexible appendages. Stability charts were derived, or can be redrawn with the desired accuracy for any particular set of design parameters. Simulation graphs of variables of interest are readily obtainable on line using program FLEXAT. Finally, applications to actual satellites, such as UK-4 and IMP-1 have been considered.

Influence of in line monitored fluid bed granulation process parameters on the stability of Ethinylestradiol.

PubMed

Roßteuscher-Carl, Katrin; Fricke, Sabine; Hacker, Michael C; Schulz-Siegmund, Michaela

2015-12-30

Ethinylestradiol (EE) as a highly active and low dosed compound is prone to oxidative degradation. The stability of the drug substance is therefore a critical parameter that has to be considered during drug formulation. Beside the stability of the drug substance, granule particle size and moisture are critical quality attributes (CQA) of the fluid bed granulation process which influence the tableting ability of the resulting granules. Both CQA should therefore be monitored during the production process by process analytic technology (PAT) according to ICH Q8. This work focusses on the effects of drying conditions on the stability of EE in a fluid-bed granulation process. We quantified EE degradation products 6-alpha-hydroxy-EE, 6-beta-hydroxy-EE, 9(11)-dehydro-EE and 6-oxo-EE during long time storage and accelerated conditions. PAT-tools that monitor granule particle size (Spatial filtering technology) and granule moisture (Microwave resonance technology) were applied and compared with off-line methods. We found a relevant influence of residual granule moisture and thermic stress applied during granulation on the storage stability of EE, whereas no degradation was found immediately after processing. Hence we conclude that drying parameters have a relevant influence on long term EE stability. Copyright © 2015 Elsevier B.V. All rights reserved.

The structures of interstitial hydrogen centers in VO 2 in the dilute limit from their vibrational properties and theory

DOE PAGES

Yin, W.; Qin, Ying; Fowler, W. B.; ...

2016-07-28

The introduction of a large concentration of H into VO 2 is known to suppress the insulating phase of the metal-insulator transition that occurs upon cooling below 340 K. We have used infrared spectroscopy and complementary theory to study the properties of interstitial H and D in VO 2 in the dilute limit to determine the vibrational frequencies, thermal stabilities, and equilibrium positions of isolated interstitial H and D centers. The vibrational lines of several OH and OD centers were observed to have thermal stabilities similar to that of the hydrogen that suppresses the insulating phase. Theory associates two ofmore » the four possible OH configurations for Hi in the insulating VO 2 monoclinic phase with OH lines seen by experiment. Furthermore, theory predicts the energies and vibrational frequencies for configurations with Hi trapped near a substitutional impurity and suggests such defects as candidates for additional OH centers that have been observed.« less

Nanoscale pinning effect evaluated from deformed nanobubbles.

PubMed

Teshima, Hideaki; Nishiyama, Takashi; Takahashi, Koji

2017-01-07

Classical thermodynamics theory predicts that nanosized bubbles should disappear in a few hundred microseconds. The surprisingly long lifetime and stability of nanobubbles are therefore interesting research subjects. It has been proposed that the stability of nanobubbles arises through pinning of the three-phase contact line, which results from intrinsic nanoscale geometrical and chemical heterogeneities of the substrate. However, a definitive explanation of nanobubble stability is still lacking. In this work, we examined the stability mechanism by introducing a "pinning force." We investigated nanobubbles at a highly ordered pyrolytic graphite/pure water interface by peak force quantitative nano-mechanical mapping and estimated the pinning force and determined its maximum value. We then observed the shape of shrinking nanobubbles. Because the diameter of the shrinking nanobubbles was pinned, the height decreased and the contact angle increased. This phenomenon implies that the stability results from the pinning force, which flattens the bubble through the pinned three-phase contact line and prevents the Laplace pressure from increasing. The pinning force can also explain the metastability of coalesced nanobubbles, which have two semispherical parts that are joined to form a dumbbell-like shape. The pinning force of the semispherical parts was stronger than that of the joint region. This result demonstrates that the contact line of the semispherical parts is pinned strongly to keep the dumbbell-like shape. Furthermore, we proposed a nanobubble generation mechanism for the solvent-exchange method and explained why the pinning force of large nanobubbles was not initially at its maximum value, as it was for small nanobubbles.

Nanoscale pinning effect evaluated from deformed nanobubbles

NASA Astrophysics Data System (ADS)

Teshima, Hideaki; Nishiyama, Takashi; Takahashi, Koji

2017-01-01

Classical thermodynamics theory predicts that nanosized bubbles should disappear in a few hundred microseconds. The surprisingly long lifetime and stability of nanobubbles are therefore interesting research subjects. It has been proposed that the stability of nanobubbles arises through pinning of the three-phase contact line, which results from intrinsic nanoscale geometrical and chemical heterogeneities of the substrate. However, a definitive explanation of nanobubble stability is still lacking. In this work, we examined the stability mechanism by introducing a "pinning force." We investigated nanobubbles at a highly ordered pyrolytic graphite/pure water interface by peak force quantitative nano-mechanical mapping and estimated the pinning force and determined its maximum value. We then observed the shape of shrinking nanobubbles. Because the diameter of the shrinking nanobubbles was pinned, the height decreased and the contact angle increased. This phenomenon implies that the stability results from the pinning force, which flattens the bubble through the pinned three-phase contact line and prevents the Laplace pressure from increasing. The pinning force can also explain the metastability of coalesced nanobubbles, which have two semispherical parts that are joined to form a dumbbell-like shape. The pinning force of the semispherical parts was stronger than that of the joint region. This result demonstrates that the contact line of the semispherical parts is pinned strongly to keep the dumbbell-like shape. Furthermore, we proposed a nanobubble generation mechanism for the solvent-exchange method and explained why the pinning force of large nanobubbles was not initially at its maximum value, as it was for small nanobubbles.

Role of the protein in the DNA sequence specificity of the cleavage site stabilized by the camptothecin topoisomerase IB inhibitor: a metadynamics study

PubMed Central

Coletta, Andrea; Desideri, Alessandro

2013-01-01

Camptothecin (CPT) is a topoisomerase IB (TopIB) selective inhibitor whose derivatives are currently used in cancer therapy. TopIB cleaves DNA at any sequence, but in the presence of CPT the only stabilized protein–DNA covalent complex is the one having a thymine in position −1 with respect to the cleavage site. A metadynamics simulation of two TopIB–DNA–CPT ternary complexes differing for the presence of a thymine or a cytosine in position −1 indicates the occurrence of two different drug’s unbinding pathways. The free-energy difference between the bound state and the transition state is large when a thymine is present in position −1 and is strongly reduced in presence of a cytosine, in line with the different drug stabilization properties of the two systems. Such a difference is strictly related to the changes in the hydrogen bond network between the protein, the DNA and the drug in the two systems, indicating a direct role of the protein in determining the specificity of the cleavage site sequence stabilized by the CPT. Calculations carried out in presence of one compound of the indenoisoquinoline family (NSC314622) indicate a comparable energy difference between the bound and the transition state independently of the presence of a thymine or a cytosine in position −1, in line with the experimental results. PMID:24003027

Mechanical stabilization of the Levitron's realistic model

NASA Astrophysics Data System (ADS)

Olvera, Arturo; De la Rosa, Abraham; Giordano, Claudia M.

2016-11-01

The stability of the magnetic levitation showed by the Levitron was studied by M.V. Berry as a six degrees of freedom Hamiltonian system using an adiabatic approximation. Further, H.R. Dullin found critical spin rate bounds where the levitation persists and R.F. Gans et al. offered numerical results regarding the initial conditions' manifold where this occurs. In the line of this series of works, first, we extend the equations of motion to include dissipation for a more realistic model, and then introduce a mechanical forcing to inject energy into the system in order to prevent the Levitron from falling. A systematic study of the flying time as a function of the forcing parameters is carried out which yields detailed bifurcation diagrams showing an Arnold's tongues structure. The stability of these solutions were studied with the help of a novel method to compute the maximum Lyapunov exponent called MEGNO. The bifurcation diagrams for MEGNO reproduce the same Arnold's tongue structure.

Decay properties and reaction dynamics of zirconium isotopes in the relativistic mean-field model

NASA Astrophysics Data System (ADS)

Panigrahi, M.; Panda, R. N.; Kumar, Bharat; Patra, S. K.

In the framework of relativistic mean-field theory, the ground state properties like binding energy, charge radius and quadrupole deformation parameter for various isotopes of zirconium from the valley of stability to drip-line region have been studied. The results are compared with the experimental data and we found reasonable agreement. The calculations are carried out for β-decay energy and β-decay half-life up to the drip-line. Total reaction and elastic differential cross-sections are also studied for few zirconium isotopes as projectiles with 12C as target, using different parameter sets namely NL3*, DD-ME2 and DD-PC1 in conjunction with Glauber model.

Interactions of oxidized multiwalled carbon nanotube with cadmium on zebrafish cell line: The influence of two co-exposure protocols on in vitro toxicity tests.

PubMed

Morozesk, Mariana; Franqui, Lidiane S; Mansano, Adrislaine S; Martinez, Diego Stéfani T; Fernandes, Marisa N

2018-05-05

The widespread production and application of carbon nanotubes (CNT) have raising concerns about their release into the environment and, the joint toxicity of CNT with pre-existing contaminants needs to be assessed. This is the first study that investigated the co-exposure of oxidized multiwalled carbon nanotubes (ox-MWCNT) and cadmium (Cd) using a zebrafish liver cell line (ZFL). Two in vitro co-exposure protocols differing by the order of ox-MWCNT interaction with Cd and fetal bovine serum (FBS) proteins were evaluated. Ox-MWCNT was physical and chemical characterized and its adsorption capacity and colloidal stability in cell culture medium was determined in both protocols. Cytotoxicity was investigated by MTT, neutral red, trypan blue, lactate dehydrogenase assays and the necrosis and apoptosis events were determined using flow cytometer. The Cd presence in medium did not interfere in the protein corona composition of MWCNT but the order of interaction of FBS and Cd interfered in its colloidal stability and metal adsorption rate. The ox-MWCNT increased Cd toxicity at low concentration probably by a "Trojan horse" and/or synergistic effect, and induced apoptosis and necrosis in ZFL cells. Although it was not observed differences of toxicity between protocols, the interaction of ox-MWCNT first with Cd led to its precipitation in cell culture medium and, as a consequence, to a possible false viability result by neutral red assay. Taken together, it was evident that the order of compounds interactions disturbs the colloidal stability and affects the in vitro toxicological assays. Considering that Protocol A showed more ox-MWCNT stability after interaction with Cd, this protocol is recommended to be adopted in future studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Genotype × Environment Interactions of Yield Traits in Backcross Introgression Lines Derived from Oryza sativa cv. Swarna/Oryza nivara

PubMed Central

Balakrishnan, Divya; Subrahmanyam, Desiraju; Badri, Jyothi; Raju, Addanki Krishnam; Rao, Yadavalli Venkateswara; Beerelli, Kavitha; Mesapogu, Sukumar; Surapaneni, Malathi; Ponnuswamy, Revathi; Padmavathi, G.; Babu, V. Ravindra; Neelamraju, Sarla

2016-01-01

Advanced backcross introgression lines (BILs) developed from crosses of Oryza sativa var. Swarna/O. nivara accessions were grown and evaluated for yield and related traits. Trials were conducted for consecutive three seasons in field conditions in a randomized complete block design with three replications. Data on yield traits under irrigated conditions were analyzed using the Additive Main Effect and Multiplicative Interaction (AMMI), Genotype and Genotype × Environment Interaction (GGE) and modified rank-sum statistic (YSi) for yield stability. BILs viz., G3 (14S) and G6 (166S) showed yield stability across the seasons along with high mean yield performance. G3 is early in flowering with high yield and has good grain quality and medium height, hence could be recommended for most of the irrigated locations. G6 is a late duration genotype, with strong culm strength, high grain number and panicle weight. G6 has higher yield and stability than Swarna but has Swarna grain type. Among the varieties tested DRRDhan 40 and recurrent parent Swarna showed stability for yield traits across the seasons. The component traits thousand grain weight, panicle weight, panicle length, grain number and plant height explained highest genotypic percentage over environment and interaction factors and can be prioritized to dissect stable QTLs/ genes. These lines were genotyped using microsatellite markers covering the entire rice genome and also using a set of markers linked to previously reported yield QTLs. It was observed that wild derived lines with more than 70% of recurrent parent genome were stable and showed enhanced yield levels compared to genotypes with higher donor genome introgressions. PMID:27807437

Prediction of Pork Longissimus Lean Color Stability Using VIS/NIR

USDA-ARS?s Scientific Manuscript database

Insufficient case-life is a costly problem facing pork processors. To assess Visible and Near-Infrared (VIS/NIR) spectroscopy as a technology to sort pork loins according to lean color stability, center-cut pork loins (n = 1208) were selected from the boning lines of four large-scale pork processor...

Stability of the quantum Sherrington-Kirkpatrick spin glass model

NASA Astrophysics Data System (ADS)

Young, A. P.

2017-09-01

I study in detail the quantum Sherrington-Kirkpatrick (SK) model, i.e., the infinite-range Ising spin glass in a transverse field, by solving numerically the effective one-dimensional model that the quantum SK model can be mapped to in the thermodynamic limit. I find that the replica symmetric solution is unstable down to zero temperature, in contrast to some previous claims, and so there is not only a line of transitions in the (longitudinal) field-temperature plane (the de Almeida-Thouless, AT, line) where replica symmetry is broken, but also a quantum de Almeida-Thouless (QuAT) line in the transverse field-longitudinal field plane at T =0 . If the QuAT line also occurs in models with short-range interactions its presence might affect the performance of quantum annealers when solving spin glass-type problems with a bias (i.e., magnetic field).

Developmental Stability Covaries with Genome-Wide and Single-Locus Heterozygosity in House Sparrows

PubMed Central

Vangestel, Carl; Mergeay, Joachim; Dawson, Deborah A.; Vandomme, Viki; Lens, Luc

2011-01-01

Fluctuating asymmetry (FA), a measure of developmental instability, has been hypothesized to increase with genetic stress. Despite numerous studies providing empirical evidence for associations between FA and genome-wide properties such as multi-locus heterozygosity, support for single-locus effects remains scant. Here we test if, and to what extent, FA co-varies with single- and multilocus markers of genetic diversity in house sparrow (Passer domesticus) populations along an urban gradient. In line with theoretical expectations, FA was inversely correlated with genetic diversity estimated at genome level. However, this relationship was largely driven by variation at a single key locus. Contrary to our expectations, relationships between FA and genetic diversity were not stronger in individuals from urban populations that experience higher nutritional stress. We conclude that loss of genetic diversity adversely affects developmental stability in P. domesticus, and more generally, that the molecular basis of developmental stability may involve complex interactions between local and genome-wide effects. Further study on the relative effects of single-locus and genome-wide effects on the developmental stability of populations with different genetic properties is therefore needed. PMID:21747940

[Optimization of Glycyrrhiza flavonoid and ferulic acid cream by reflect-line orthogonal simplex method].

PubMed

Liu, Sheng; Xie, Jun; Chen, Xiangqing; Yang, Liqiang; Su, Dan; Fang, Yan; Yu, Na; Fang, Wei

2010-02-01

To optimize the formula of Glycyrrhiza flavonoid and ferulic acid cream and set up its quality control parameters. Reflect-line orthogonal simplex method was used to optimize the main factors such as amount of Myrj52-glyceryl monostearate and dimethicone, based on the appearance, spreadability and stability of the cream. 9.0% Myrj52-glyceryl monostearate (3:2) and 2.5% dimethicone were chosen in prescription. The prepared cream presented a good stability after being placed 24 h at 5 degrees C, 25 degrees C and 37 degrees C respectively,and its spreadability suited with the property of semi-fluid cream. [corrected] The formula of Glycyrrhiza flavonoid and ferulic acid cream is suitable, and its quality is stable. The reflect-line orthogonal simplex method is suitable for the formula optimization of cream.

Single steady frequency and narrow-linewidth external-cavity semiconductor laser

NASA Astrophysics Data System (ADS)

Zhao, Weirui; Jiang, Pengfei; Xie, Fuzeng

2003-11-01

A single longitudinal mode and narrow line width external cavity semiconductor laser is proposed. It is constructed with a semiconductor laser, collimator, a flame grating, and current and temperature control systems. The one facet of semiconductor laser is covered by high transmission film, and another is covered by high reflection film. The flame grating is used as light feedback element to select the mode of the semiconductor laser. The temperature of the constructed external cavity semiconductor laser is stabilized in order of 10-3°C by temperature control system. The experiments have been carried out and the results obtained - the spectral line width of this laser is compressed to be less than 1.4MHz from its original line-width of more than 1200GHz and the output stability (including power and mode) is remarkably enhanced.

Low-speed wind-tunnel investigation of the stability and control characteristics of a series of flying wings with sweep angles of 50 deg

NASA Technical Reports Server (NTRS)

Fears, Scott P.; Ross, Holly M.; Moul, Thomas M.

1995-01-01

A wind-tunnel investigation was conducted in the Langley 12-Foot Low-Speed Tunnel to study the low-speed stability and control characteristics of a series of four flying wings over an extended range of angle of attack (-8 deg to 48 deg). Because of the current emphasis on reducing the radar cross section (RCS) of new military aircraft, the planform of each wing was composed of lines swept at a relatively high angle of 50 deg, and all the trailing-edge lines were aligned with one of the two leading edges. Three arrow planforms with different aspect ratios and one diamond planform were tested. The models incorporated leading-edge flaps for improved longitudinal characteristics and lateral stability and had trailing-edge flaps in three segments that were deflected differentially for roll control, symmetrically for pitch control, and in a split fashion for yaw control. Three top body widths and two sizes of twin vertical tails were also tested on each model. A large aerodynamic database was compiled that could be used to evaluate some of the trade-offs involved in the design of a configuration with a reduced RCS and good flight dynamic characteristics.

Low-speed wind-tunnel investigation of the stability and control characteristics of a series of flying wings with sweep angles of 70 deg

NASA Technical Reports Server (NTRS)

Ross, Holly M.; Fears, Scott P.; Moul, Thomas M.

1995-01-01

A wind-tunnel investigation was conducted in the Langley 12-Foot Low-Speed Tunnel to study the low-speed stability and control characteristics of a series of four flying wings over an extended range of angle of attack (-8 deg to 48 deg). Because of the current emphasis on reducing the radar cross section (RCS) of new military aircraft, the planform of each wing was composed of lines swept at a relatively high angle of 70 deg, and all the trailing edges and control surface hinge lines were aligned with one of the two leading edges. Three arrow planforms with different aspect ratios and one diamond planform were tested. The models incorporated leading-edge flaps for improved longitudinal characteristics and lateral stability and had three sets of trailing-edge flaps that were deflected differentially for roll control, symmetrically for pitch control, and in a split fashion for yaw control. Three top body widths and two sizes of twin vertical tails were also tested on each model. A large aerodynamic database was compiled that could be used to evaluate some of the trade-offs involved in the design of a configuration with a reduced RCS and good flight dynamic characteristics.

Low-speed wind tunnel investigation of the stability and control characteristics of a series of flying wings with sweep angles of 60 deg

NASA Technical Reports Server (NTRS)

Moul, Thomas M.; Fears, Scott P.; Ross, Holly M.; Foster, John V.

1995-01-01

A wind tunnel investigation was conducted in the Langley 12-Foot Low-Speed Wind Tunnel to study the low-speed stability and control characteristics of a series of four flying wings over an extended range of angle of attack (-8 deg to 48 deg). Because of the current emphasis on reducing the radar cross section of new military aircraft, the planform of each wing was composed of lines swept at a relatively high angle of 60 deg, and all the trailing-edge lines were aligned with one of the two leading edges. Three arrow planforms with different aspect ratios and one diamond planform were tested. The models incorporated leading-edge flaps for improved pitching-moment characteristics and lateral stability and had three sets of trailing-edge flaps that were deflected differentially for roll control, symmetrically for pitch control, and in a split fashion for yaw control. Top bodies of three widths and twin vertical tails of various sizes and locations were also tested on each model. A large aerodynamic database was compiled that could be used to evaluate some of the trade-offs involved in the design of a configuration with a reduced radar cross section and good flight dynamic characteristics.

On the impact of fjord geometry on grounding line stability

NASA Astrophysics Data System (ADS)

Åkesson, H.; Nick, F. M.; Morlighem, M.; Nisancioglu, K. H.

2016-12-01

Observations and reconstructions of Antarctic and Greenland marine-terminating glaciers and their grounding lines show that their response to external forcings is highly dependent on the geometry of individual glaciers, such as fjord geometry. While recent retreat of these glaciers is broadly consistent with warmer atmospheric and oceanic conditions, we observe considerable spatial and temporal variability, with diverse glacier behavior within the same regions. The relatively short observational record of marine-terminating glaciers also needs to be placed in a long-term context. Reconstructions of marine-terminating glaciers, however, indicate highly asynchronous retreat histories despite being subject to similar climatic forcings. These lines of evidence suggest that regional climate forcing alone cannot explain marine-terminating glacier behavior, and that these glaciers cannot be used uncritically as indicators of past climates because of their heterogeneous response to climate change. Here we use a dynamic flowline model with a physical treatment of iceberg calving to assess the effect of fjord geometry on grounding line stability on decadal and longer time scales. The model includes driving and resistive stresses of ice flow and is applied to idealized fjord geometries representing different real-world glaciers. We find that the geometry can override the signal from the ambient forcing over multiple centuries, resulting in non-linear, rapid grounding line migration. In particular we highlight the importance of fjord width, which has received relatively little attention in terms of marine ice sheet instability. Our findings provide new insights into grounding line behavior and may explain some of the documented heterogeneous, asynchronous patterns of marine-terminating glaciers in Greenland, Antarctica, Alaska and elsewhere. Further, we investigate the geometric influence on the reversibility and hysteresis of grounding line migration, relevant for oscillatory glacier behavior, marine-terminating glacier retreat-advance cycles and Heinrich events. Finally, we present comparative, preliminary results using the 3-dimensional ice sheet model ISSM and discuss our findings in terms of ice shelf stability and buttressing.

Establishment and Characterization of a New Muscle Cell Line of Zebrafish (Danio rerio) as an In Vitro Model for Gene Expression Studies.

PubMed

Kumar, Amit; Singh, Neha; Goswami, Mukunda; Srivastava, J K; Mishra, Akhilesh K; Lakra, W S

2016-01-01

A new continuous fibroblast cell line was established from the muscle tissue of healthy juvenile Danio rerio (Zebrafish) through explant method. Fish cell lines serve as useful tool for investigating basic fish biology, as a model for bioassay of environmental toxicant, toxicity ranking, and for developing molecular biomarkers. The cell line was continuously subcultured for a period of 12 months (61 passages) and maintained at 28 °C in L-15 medium supplemented with 10% FBS and 10 ng/mL of basic fibroblastic growth factor (bFGF) without use of antibiotics. Its growth rate was proportional to the FBS concentration, with optimum growth at 15% FBS. DNA barcoding (16SrRNA and COX1) was used to authenticate the cell line. Cells were incubated with propidium iodide and sorted via flow cytometry to calculate the DNA content to confirm the genetic stability. Significant green fluorescent protein (GFP) signals confirmed the utility of cell line in transgenic and genetic manipulation studies. In vitro assay was performed with MTT to examine the growth potential of the cell line. The muscle cell line would provide a novel invaluable in vitro model to identify important genes to understand regulatory mechanisms that govern the molecular regulation of myogenesis and should be useful in biomedical research.

Evaluation of synthesized platinum nanoparticles on the MCF-7 and HepG-2 cancer cell lines

NASA Astrophysics Data System (ADS)

Mohammadi, Hadi; Abedi, Anita; Akbarzadeh, Azim; Mokhtari, Mohammad Javad; Shahmabadi, Hasan Ebrahimi; Mehrabi, Mohamad Reza; Javadian, Saifuddin; Chiani, Mohsen

2013-04-01

Platinum nanoparticles (PNPs) were synthesized by chemical reduction of potassium hexachloroplatinate (IV) with trisodium citrate under vigorous stirring and addition of sodium dodecyl sulfate as stabilizer reagent. Reducing agent was chosen depending on the oxidation reactions and potential values of the chemical materials used in the experiment. The aim of this study is to investigate the effects of PNPs on the different cancer cell lines and cytotoxicity study of this nanomaterial. The morphology of PNPs was investigated by scanning electron microscope (XL30, Philips Electronics, Amsterdam, The Netherlands) with the ability to perform elemental analysis by EDX. Malvern Zetasizer 3000 HSA (Malvern Instruments, Worcestershire, UK) was used to determine the distribution of particle size and zeta potential of PNPs. The cytotoxicity property of the nanoparticles was evaluated by MTT assay on MCF-7 and HepG-2 cell lines, and the cytotoxic concentration 50% values were determined for 24 h.

[Genetic study on two maize male sterile mutants obtained by space mutagenesis].

PubMed

Li, Yu-Ling; Yu, Yong-Liang; Liu, Yan-Xia; Li, Xue-Hui; Fu, Jia-Feng

2007-06-01

Two maize male sterile mutants were selected from the offspring of four maize inbred lines, which were carried into space by the Shenzhou spaceship 4. Their genetic characteristic and stability was analyzed in present study. Crosses were made between the male sterile plants and fertile plants from the same line, and other inbred lines with normal cytoplasm. The ratios of the sterile plants with the fertile plants in their F1, F2 generations, and their reciprocal backcross generations with the male sterile plants were calculated. The results showed that the characteristic in male sterility was stable in different years, different seasons and different locations, and was inheritable from generation to generation. This male sterile was controlled by a single nuclear recessive gene. Since no pollens or a few malformed pollens existed in the anther of the sterile plants, it was a completely sterile type.

Fingering instability of Bingham fluids

NASA Astrophysics Data System (ADS)

Ghadge, Shilpa; Myers, Tim

2005-11-01

Contact line instabilities have been extensively studied and many useful results obtained for industrial applications. Our research in this area is to explore these instabilities for non-Newtonian fluids which has wide scope in geological, biological as well as industrial areas. In this talk, we will present an analysis of fingering instability near a contact line of the thin sheet of fluid flowing down on a moderately inclined plane. This instability has been well studied for Newtonian fluids. We explore the effect of a yield strength of the fluid on this instability. We have conveniently assumed the presence of the precussor film of small thickness ahead of the fluid film to avoid some mathematical singularities. Using a lubrication-type approximation, we perform a linear stability analysis of a straight contact line. We will show comparison with some experimental results using suspensions of kaolin in silicone oil as a yield strength fluid.

C 90 temperature effects on relative stabilities of the IPR isomers

NASA Astrophysics Data System (ADS)

Slanina, Zdeněk; Zhao, Xiang; Lee, Shyi-Long; Ōsawa, Eiji

1997-07-01

The complete set of 46 isolated-pentagon-rule (IPR) isomers of C 90 is treated by the SAMI quantum-chemical method (Semi-Ab-Initio Model 1), and their energetics is also checked by ab initio SCF computations (HF/3-21G, HF/4-31G) and the AM1 and PM3 semiempirical methods. All the methods point out a C2 species as the system state (with an exception at the HF/3-21G level). However, the energetics itself is not able to produce a good agreement with recent observations (one C2 v, three C2, and one C1, separeted into three HPLC fractions). The symmetries of the five SAM1 lowest-energy structures are: C2, C2 v, Cs, D5 h, C1. In order to respect temperature effects on relative stabilities, entropy contributions are also computed and significant changes are found. The symmetries of the five structures most populated in a high-temperature region are according to the SAM1 computations: two times C2, Cs, C2 v, C1. One of the recently reported HPLC fractions shows 70 lines in the 13C NMR spectrum, assigned to a C2 species (45 lines) and C2 v species (25 lines, 5 weaker). There is however an alternative interpretation of the spectrum: a Cs (46 lines, 2 weaker) and a C2 v species (24 lines, 3 weaker). The last two structures are indeed present in the SAM1 high-temperature stability set so that agreement between observations and calculations can be achieved.

Genetic potential of black bean genotypes with predictable behaviors in multienvironment trials.

PubMed

Torga, P P; Melo, P G S; Pereira, H S; Faria, L C; Melo, L C

2016-10-24

The aim of this study was to evaluate the phenotypic stability and specific and broad adaptability of common black bean genotypes for the Central and Center-South regions of Brazil by using the Annicchiarico and AMMI (weighted average of absolute scores: WAAS, and weighted average of absolute scores and productivity: WAASP) methodologies. We carried out 69 trials, with 43 and 26 trials in the Central and Center-South regions, respectively. Thirteen genotypes were evaluated in a randomized block design with three replications, during the rainy, dry, and winter seasons in 2 years. To obtain estimates of specific adaptation, we analyzed the parameters for each method obtained in the two geographic regions separately. To estimate broad adaptation, we used the average of the parameters obtained from each region. The lines identified with high specific adaptation in each region were not the same based on the Annicchiarico and AMMI (WAAS) methodologies. It was not possible to identify the same genotypes with specific or broad stability by using these methods. By contrast, the Annicchiarico and AMMI (WAASP) methods presented very similar estimates of broad and specific adaptation. Based on these methods, the lines with more specific adaptation were CNFP 8000 and CNFP 7994, in the Central and Center-South regions, respectively, of which the CNFP 8000 line was more widely adapted.

Pharmacological importance, characterization and applications of gold and silver nanoparticles synthesized by Panax ginseng fresh leaves.

PubMed

Singh, Priyanka; Singh, Hina; Ahn, Sungeun; Castro-Aceituno, Verónica; Jiménez, Zuly; Simu, Shakina Yesmin; Kim, Yeon Ju; Yang, Deok Chun

2017-11-01

Previously, we showed the rapid and eco-friendly synthesis of gold and silver nanoparticles within 3 and 45 min by fresh leaves extract of herbal medicinal plant Panax ginseng. In addition, we characterized the nanoparticles in terms of shape, size, morphology and stability by FE-TEM, EDX, elemental mapping, SEAD, XRD and particles size analysis. In addition of this, we showed their antimicrobial, anti-coagulant, and biofilm inhibition activity of nanoparticles. Continuing our previous study, here we highlight the further characterization and biomedical applications of P. ginseng leaf-mediated gold and silver nanoparticles. We characterized the nanoparticles further in terms of active functional group and capping layer, surface charge, and temperature stability. Based on these factors, we explored the nanoparticles for antioxidant efficacy, biocompatibility in HaCaT cells, 3T3-L1 pre-adipocytes cells, for anticancer efficacy in A549 lung cancer and B16BL6 skin melenoma cancer cell lines and for anti-inflammation efficacy in RAW 264.7 cell lines. Based on our findings, we suggest that the P. ginseng-mediated gold nanoparticles have high antioxidant activity and highly biocompatibility in HaCaT cells, 3T3-L1 pre-adipocytes cells, RAW 264.7 cells lines and could be considered for future drug delivery carriers. The silver nanoparticles also showed high potent antioxidant efficacy, additionally it showed high anticancer effect in A549 lung cancer and B16BL6 skin melenoma cancer cell lines as compared to precursor salts. Moreover, both gold and silver nanoparticles have anti-inflammatory efficacies in RAW 264.7 cells. Thus, the study may provide useful insights of P. ginseng leaves extract-mediated biocompatible gold and silver nanoparticles and improving their applicability in designing nanoparticles carrier systems for drug delivery applications.

Say hello to the DSO

NASA Astrophysics Data System (ADS)

Pate, G.; Roberts, T.

1981-05-01

In the 2-to-10 GHz frequency range, the dielectrically stabilized oscillators (DSOs) with their small size, simple construction, and modest bias requirements, have advantages over cavity-stabilized oscillators (CSOs) and crystal-controlled multiplier chains (XCOs). Commercially available DSOs consist of a transistor oscillator locked to some frequency by a resonant disk of dielectric material. The disk is coupled to a microstrip line at the output of the oscillator. The stability of a DSO lies between that of a crystal-controlled oscillator and that of a cavity-stabilized oscillator. Dielectrically stabilized oscillators, built with nine basic parts and few solder joints, can be expected to be much more reliable than a CSO or XCO.

Flight-Test Evaluation of the Longitudinal Stability and Control Characteristics of 0.5-Scale Models of the Fairchild Lark Pilotless-Aircraft Configuration: Standard Configuration with Wing Flaps Deflected 60 Degrees and Model having Tail in Line with Wings, TED No. NACA 2387

NASA Technical Reports Server (NTRS)

Stone, David G.

1947-01-01

Flight tests were conducted at the Flight Test Station of the Pilotless Aircraft Research Division at Wallop Island, Va., to determine the longitudinal control and stability characteristics of 0.5-scale models of the Fairchild Lark pilotless aircraft with the tail in line with the wings a d with the horizontal wing flaps deflected 60 deg. The data were obtained by the use of a telemeter and by radar tracking.

A Technique for Measuring Rotocraft Dynamic Stability in the 40 by 80 Foot Wind Tunnel

NASA Technical Reports Server (NTRS)

Gupta, N. K.; Bohn, J. G.

1977-01-01

An on-line technique is described for the measurement of tilt rotor aircraft dynamic stability in the Ames 40- by 80-Foot Wind Tunnel. The technique is based on advanced system identification methodology and uses the instrumental variables approach. It is particulary applicable to real time estimation problems with limited amounts of noise-contaminated data. Several simulations are used to evaluate the algorithm. Estimated natural frequencies and damping ratios are compared with simulation values. The algorithm is also applied to wind tunnel data in an off-line mode. The results are used to develop preliminary guidelines for effective use of the algorithm.

Computerized dynamic posturography: the influence of platform stability on postural control.

PubMed

Palm, Hans-Georg; Lang, Patricia; Strobel, Johannes; Riesner, Hans-Joachim; Friemert, Benedikt

2014-01-01

Postural stability can be quantified using posturography systems, which allow different foot platform stability settings to be selected. It is unclear, however, how platform stability and postural control are mathematically correlated. Twenty subjects performed tests on the Biodex Stability System at all 13 stability levels. Overall stability index, medial-lateral stability index, and anterior-posterior stability index scores were calculated, and data were analyzed using analysis of variance and linear regression analysis. A decrease in platform stability from the static level to the second least stable level was associated with a linear decrease in postural control. The overall stability index scores were 1.5 ± 0.8 degrees (static), 2.2 ± 0.9 degrees (level 8), and 3.6 ± 1.7 degrees (level 2). The slope of the regression lines was 0.17 for the men and 0.10 for the women. A linear correlation was demonstrated between platform stability and postural control. The influence of stability levels seems to be almost twice as high in men as in women.

A General Framework for Interrogation of mRNA Stability Programs Identifies RNA-Binding Proteins that Govern Cancer Transcriptomes.

PubMed

Perron, Gabrielle; Jandaghi, Pouria; Solanki, Shraddha; Safisamghabadi, Maryam; Storoz, Cristina; Karimzadeh, Mehran; Papadakis, Andreas I; Arseneault, Madeleine; Scelo, Ghislaine; Banks, Rosamonde E; Tost, Jorg; Lathrop, Mark; Tanguay, Simon; Brazma, Alvis; Huang, Sidong; Brimo, Fadi; Najafabadi, Hamed S; Riazalhosseini, Yasser

2018-05-08

Widespread remodeling of the transcriptome is a signature of cancer; however, little is known about the post-transcriptional regulatory factors, including RNA-binding proteins (RBPs) that regulate mRNA stability, and the extent to which RBPs contribute to cancer-associated pathways. Here, by modeling the global change in gene expression based on the effect of sequence-specific RBPs on mRNA stability, we show that RBP-mediated stability programs are recurrently deregulated in cancerous tissues. Particularly, we uncovered several RBPs that contribute to the abnormal transcriptome of renal cell carcinoma (RCC), including PCBP2, ESRP2, and MBNL2. Modulation of these proteins in cancer cell lines alters the expression of pathways that are central to the disease and highlights RBPs as driving master regulators of RCC transcriptome. This study presents a framework for the screening of RBP activities based on computational modeling of mRNA stability programs in cancer and highlights the role of post-transcriptional gene dysregulation in RCC. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Influence of lateral discomfort on the stability of traffic flow based on visual angle car-following model

NASA Astrophysics Data System (ADS)

Zheng, Liang; Zhong, Shiquan; Jin, Peter J.; Ma, Shoufeng

2012-12-01

Due to the poor road markings and irregular driving behaviors, not every vehicle is positioned in the center of the lane. The deviation from the center can cause discomfort to drivers in the neighboring lane, which is referred to as lateral discomfort (or lateral friction). Such lateral discomfort can be incorporated into the driver stimulus-response framework by considering the visual angle and its changing rate from the psychological viewpoint. In this study, a two-lane visual angle based car-following model is proposed and its stability condition is obtained through linear stability theory. Further derivations indicate that the neutral stability line of the model is asymmetry and four factors including the vehicle width and length, the lateral separation and the sensitivity regarding the changing rate of visual angle have large impacts on the stability of traffic flow. Numerical simulations further verify these theoretical results, and demonstrate that the behaviors of diverging, merging and lane changing can break the original steady state and cause traffic fluctuations. However, these fluctuations may be alleviated to some extent by reducing the lateral discomfort.

Ultralow-frequency-noise stabilization of a laser by locking to an optical fiber-delay line.

PubMed

Kéfélian, Fabien; Jiang, Haifeng; Lemonde, Pierre; Santarelli, Giorgio

2009-04-01

We report the frequency stabilization of an erbium-doped fiber distributed-feedback laser using an all-fiber-based Michelson interferometer of large arm imbalance. The interferometer uses a 1 km SMF-28 optical fiber spool and an acousto-optic modulator allowing heterodyne detection. The frequency-noise power spectral density is reduced by more than 40 dB for Fourier frequencies ranging from 1 Hz to 10 kHz, corresponding to a level well below 1 Hz2/Hz over the entire range; it reaches 10(-2) Hz2/Hz at 1 kHz. Between 40 Hz and 30 kHz, the frequency noise is shown to be comparable to the one obtained by Pound-Drever-Hall locking to a high-finesse Fabry-Perot cavity. Locking to a fiber delay line could consequently represent a reliable, simple, and compact alternative to cavity stabilization for short-term linewidth reduction.

Mechanical behavior and shape optimization of lining structure for subsea tunnel excavated in weathered slot

NASA Astrophysics Data System (ADS)

Li, Peng-fei; Zhou, Xiao-jun

2015-12-01

Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang'an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.

Aeroelastic impact of above-rated wave-induced structural motions on the near-wake stability of a floating offshore wind turbine rotor

NASA Astrophysics Data System (ADS)

Rodriguez, Steven; Jaworski, Justin

2017-11-01

The impact of above-rated wave-induced motions on the stability of floating offshore wind turbine near-wakes is studied numerically. The rotor near-wake is generated using a lifting-line free vortex wake method, which is strongly coupled to a finite element solver for kinematically nonlinear blade deformations. A synthetic time series of relatively high-amplitude/high-frequency representative of above-rated conditions of the NREL 5MW referece wind turbine is imposed on the rotor structure. To evaluate the impact of these above-rated conditions, a linear stability analysis is first performed on the near wake generated by a fixed-tower wind turbine configuration at above-rated inflow conditions. The platform motion is then introduced via synthetic time series, and a stability analysis is performed on the wake generated by the floating offshore wind turbine at the same above-rated inflow conditions. The stability trends (disturbance modes versus the divergence rate of vortex structures) of the two analyses are compared to identify the impact that above-rated wave-induced structural motions have on the stability of the floating offshore wind turbine wake.

76 FR 49533 - Spyker Automobielen B.V.; Receipt of Application for Temporary Exemption from FMVSS No. 126

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-10

... Standard (FMVSS) No. 126, Electronic Stability Control Systems. SUMMARY: In accordance with the procedures... line of vehicles from the requirements of FMVSS No. 126, the standard for electronic stability control systems. The basis of the application is that compliance would cause substantial economic hardship to a...

Pinning Stabilizes Neighboring Surface Nanobubbles against Ostwald Ripening.

PubMed

Dollet, Benjamin; Lohse, Detlef

2016-11-01

Pinning of the contact line and gas oversaturation explain the stability of single surface nanobubbles. In this article, we theoretically show that the pinning also suppresses the Ostwald ripening process between neighboring surface nanobubbles, thus explaining why in a population of neighboring surface nanobubbles different radii of curvature of the nanobubbles can be observed.

Stability analysis of cylinders with circular cutouts

NASA Technical Reports Server (NTRS)

Almroth, B. O.; Brogan, F. A.; Marlowe, M. B.

1973-01-01

The stability of axially compressed cylinders with circular cutouts is analyzed numerically. An extension of the finite-difference method is used which removes the requirement that displacement components be defined in the directions of the grid lines. The results of this nonlinear analysis are found to be in good agreement with earlier experimental results.

Optical frequency locked loop for long-term stabilization of broad-line DFB laser frequency difference

NASA Astrophysics Data System (ADS)

Lipka, Michał; Parniak, Michał; Wasilewski, Wojciech

2017-09-01

We present an experimental realization of the optical frequency locked loop applied to long-term frequency difference stabilization of broad-line DFB lasers along with a new independent method to characterize relative phase fluctuations of two lasers. The presented design is based on a fast photodiode matched with an integrated phase-frequency detector chip. The locking setup is digitally tunable in real time, insensitive to environmental perturbations and compatible with commercially available laser current control modules. We present a simple model and a quick method to optimize the loop for a given hardware relying exclusively on simple measurements in time domain. Step response of the system as well as phase characteristics closely agree with the theoretical model. Finally, frequency stabilization for offsets within 4-15 GHz working range achieving <0.1 Hz long-term stability of the beat note frequency for 500 s averaging time period is demonstrated. For these measurements we employ an I/Q mixer that allows us to precisely and independently measure the full phase trace of the beat note signal.

Impact of humidity on functionality of on-paper printed electronics.

PubMed

Bollström, Roger; Pettersson, Fredrik; Dolietis, Peter; Preston, Janet; Osterbacka, Ronald; Toivakka, Martti

2014-03-07

A multilayer coated paper substrate, combining barrier and printability properties was manufactured utilizing a pilot-scale slide curtain coating technique. The coating structure consists of a thin mineral pigment layer coated on top of a barrier layer. The surface properties, i.e. smoothness and surface porosity, were adjusted by the choice of calendering parameters. The influence of surface properties on the fine line printability and conductivity of inkjet-printed silver lines was studied. Surface roughness played a significant role when printing narrow lines, increasing the risk of defects and discontinuities, whereas for wider lines the influence of surface roughness was less critical. A smooth, calendered surface resulted in finer line definition, i.e. less edge raggedness. Dimensional stability and its influence on substrate surface properties as well as on the functionality of conductive tracks and transistors were studied by exposure to high/low humidity cycles. The barrier layer of the multilayer coated paper reduced the dimensional changes and surface roughness increase caused by humidity and helped maintain the conductivity of the printed tracks. Functionality of a printed transistor during a short, one hour humidity cycle was maintained, but a longer exposure to humidity destroyed the non-encapsulated transistor.

Mitoguazone induces apoptosis via a p53-independent mechanism.

PubMed

Davidson, K; Petit, T; Izbicka, E; Koester, S; Von Hoff, D D

1998-08-01

Mitoguazone (methylglyoxal bisguanylhydrazone, methyl-GAG or MGBG) is a synthetic polycarbonyl derivative with activity in patients with Hodgkin's and non-Hodgkin's lymphoma, head and neck cancer, prostate cancer, and esophageal cancer. Mitoguazone has also recently been documented to have activity in patients with AIDS-related lymphoma. Among anticancer drugs, mitoguazone has a unique mechanism of action via interference with the polyamine biosynthetic pathway. Polyamines stabilize DNA structure by non-covalent cross-bridging between phosphate groups on opposite strands. In addition, mitoguazone causes uncoupling of oxidative phosphorylation. In this study, the ability of mitoguazone to induce apoptosis by inhibiting the polyamine pathway was assessed in three Burkitt's lymphoma cell lines (Raji, Ramos and Daudi) and one prostate carcinoma cell line (MPC 3). Additional evaluations were performed in two human breast cancer cell lines (MCF7 with wild-type p53 and VM4K with mutated p53) to determine whether the p53 tumor suppressor gene was required for efficient apoptosis induction. The present study demonstrated that mitoguazone induces apoptosis in all the different human cancer cell lines tested in a concentration- and time-dependent way, and triggers a p53-independent programmed cell death in the human breast cancer MCF7 cell line.

Genomic instability of osteosarcoma cell lines in culture: impact on the prediction of metastasis relevant genes.

PubMed

Muff, Roman; Rath, Prisni; Ram Kumar, Ram Mohan; Husmann, Knut; Born, Walter; Baudis, Michael; Fuchs, Bruno

2015-01-01

Osteosarcoma is a rare but highly malignant cancer of the bone. As a consequence, the number of established cell lines used for experimental in vitro and in vivo osteosarcoma research is limited and the value of these cell lines relies on their stability during culture. Here we investigated the stability in gene expression by microarray analysis and array genomic hybridization of three low metastatic cell lines and derivatives thereof with increased metastatic potential using cells of different passages. The osteosarcoma cell lines showed altered gene expression during in vitro culture, and it was more pronounced in two metastatic cell lines compared to the respective parental cells. Chromosomal instability contributed in part to the altered gene expression in SAOS and LM5 cells with low and high metastatic potential. To identify metastasis-relevant genes in a background of passage-dependent altered gene expression, genes involved in "Pathways in cancer" that were consistently regulated under all passage comparisons were evaluated. Genes belonging to "Hedgehog signaling pathway" and "Wnt signaling pathway" were significantly up-regulated, and IHH, WNT10B and TCF7 were found up-regulated in all three metastatic compared to the parental cell lines. Considerable instability during culture in terms of gene expression and chromosomal aberrations was observed in osteosarcoma cell lines. The use of cells from different passages and a search for genes consistently regulated in early and late passages allows the analysis of metastasis-relevant genes despite the observed instability in gene expression in osteosarcoma cell lines during culture.

Control of motion stability of the line tracer robot using fuzzy logic and kalman filter

NASA Astrophysics Data System (ADS)

Novelan, M. S.; Tulus; Zamzami, E. M.

2018-03-01

Setting of motion and balance line tracer robot two wheels is actually a combination of a two-wheeled robot balance concept and the concept of line follower robot. The main objective of this research is to maintain the robot in an upright and can move to follow the line of the Wizard while maintaining balance. In this study the motion balance system on line tracer robot by considering the presence of a noise, so that it takes the estimator is used to mengestimasi the line tracer robot motion. The estimation is done by the method of Kalman Filter and the combination of Fuzzy logic-Fuzzy Kalman Filter called Kalman Filter, as well as optimal smooting. Based on the results of the study, the value of the output of the fuzzy results obtained from the sensor input value has been filtered before entering the calculation of the fuzzy. The results of the output of the fuzzy logic hasn’t been able to control dc motors are well balanced at the moment to be able to run. The results of the fuzzy logic by using membership function of triangular membership function or yet can control with good dc motor movement in order to be balanced

A compact frequency stabilized telecom laser diode for space applications

NASA Astrophysics Data System (ADS)

Philippe, C.; Holleville, D.; Le Targat, R.; Wolf, P.; Leveque, T.; Le Goff, R.; Martaud, E.; Acef, O.

2017-09-01

We report on a Telecom laser diode (LD) frequency stabilization to a narrow iodine hyperfine line in the green range, after frequency tripling process using fibered nonlinear waveguide PPLN crystals. We have generated up to 300 mW optical power in the green range ( 514 nm) from 800 mW of infrared power ( 1542 nm), corresponding to a nonlinear conversion efficiency h = P3?/P? 36%. Less than 10 mW of the generated green power are used for Doppler-free spectroscopy of 127I2 molecular iodine, and -therefore- for the frequency stabilization purpose. The frequency tripling optical setup is very compact (< 5 l), fully fibered, and could operate over the full C-band of the Telecom range (1530 nm - 1565 nm). Several thousands of hyperfine iodine lines may thus be interrogated in the 510 nm - 521 nm range. We build up an optical bench used at first in free space configuration, using the well-known modulation transfer spectroscopy technique (MTS), in order to test the potential of this new frequency standard based on the couple "1.5 ?m laser / iodine molecule". We have already demonstrated a preliminary frequency stability of 4.8 x 10-14 ? -1/2 with a minimum value of 6 x 10-15 reached after 50 s of integration time, conferred to a laser diode operating at 1542.1 nm. We focus now our efforts to expand the frequency stability to a longer integration time in order to meet requirements of many space experiments, such earth gravity missions, inters satellites links or space to ground communications. Furthermore, we investigate the potential of a new approach based on frequency modulation technique (FM), associated to a 3rd harmonic detection of iodine lines to increase the compactness of the optical setup.

One-dimensional terahertz imaging of surfactant-stabilized dodecane-brine emulsion

NASA Astrophysics Data System (ADS)

Nickel, Daniel Vincent

Terahertz line-images of surfactant-stabilized dodecane(C12H 26)-brine emulsions are obtained by translating the emulsified region through the focus of a terahertz time-domain spectrometer, capturing a time-domain waveform at each vertical position. From these images, relative dodecane content, emulsion size, and stability can be extracted to evaluate the efficacy of the surfactant in solvating the dodecane. In addition, the images provide insight into the dynamics of concentrated emulsions after mixing.

[Molecular and biologic characteristics of attenuated rubella viruses].

PubMed

Lavrent'eva, I N

2008-01-01

To study stability/variability of rubella virus vaccine strain "Orlov-B" during its adaptation to other tissue substrate. Vaccine strains of rubella virus Wistar 27/3 and "Orlov-B" as well as wild type strains "Orlov-D" and "Lebedev" were used. Rhesus monkeys were used as laboratory animals. Standard virological, molecular and statistical methods were applied. Obtained as a result of adaptation to other tissue substrate - diploid human cell line M-22 - strain "Orlov-D" demonstrated stability on RCT40 sign in in vitro experiments. Comparative genotyping of "Orlov-B" and "Orlov-D" strains on gene E1 showed identity of nucleotide sequences of both variants. Genetic stability of virus on the gene coding the most immunogenic protein E1 was confirmed in vivo: the stable high immunogenic and protective activity of both "Orlov-B" and "Orlov- D" strains was demonstrated in experiments on rhesus macaques. New data on stability of attenuated rubella virus vaccine strains have practical significance for the development of new vaccines.

The dynamics and control of large flexible space structures. Volume 3, part B: The modelling, dynamics, and stability of large Earth pointing orbiting structures

NASA Technical Reports Server (NTRS)

Bainum, P. M.; Kumar, V. K.

1980-01-01

The dynamics and stability of large orbiting flexible beams, and platforms and dish type structures oriented along the local horizontal are treated both analytically and numerically. It is assumed that such structures could be gravitationally stabilized by attaching a rigid light-weight dumbbell at the center of mass by a spring loaded hinge which also could provide viscous damping. For the beam, the small amplitude inplane pitch motion, dumbbell librational motion, and the anti-symmetric elastic modes are all coupled. The three dimensional equations of motion for a circular flat plate and shallow spherical shell in orbit with a two-degree-of freedom gimballed dumbbell are also developed and show that only those elastic modes described by a single nodal diameter line are influenced by the dumbbell motion. Stability criteria are developed for all the examples and a sensitivity study of the system response characteristics to the key system parameters is carried out.

Stability of a Model Explaining Selected Extramusical Influences on Solo and Small-Ensemble Festival Ratings

ERIC Educational Resources Information Center

Bergee, Martin J.; Westfall, Claude R.

2005-01-01

This is the third study in a line of inquiry whose purpose has been to develop a theoretical model of selected extra musical variables' influence on solo and small-ensemble festival ratings. Authors of the second of these (Bergee & McWhirter, 2005) had used binomial logistic regression as the basis for their model-formulation strategy. Their…

A decision tree-based on-line preventive control strategy for power system transient instability prevention

NASA Astrophysics Data System (ADS)

Xu, Yan; Dong, Zhao Yang; Zhang, Rui; Wong, Kit Po

2014-02-01

Maintaining transient stability is a basic requirement for secure power system operations. Preventive control deals with modifying the system operating point to withstand probable contingencies. In this article, a decision tree (DT)-based on-line preventive control strategy is proposed for transient instability prevention of power systems. Given a stability database, a distance-based feature estimation algorithm is first applied to identify the critical generators, which are then used as features to develop a DT. By interpreting the splitting rules of DT, preventive control is realised by formulating the rules in a standard optimal power flow model and solving it. The proposed method is transparent in control mechanism, on-line computation compatible and convenient to deal with multi-contingency. The effectiveness and efficiency of the method has been verified on New England 10-machine 39-bus test system.

Constrained off-line synthesis approach of model predictive control for networked control systems with network-induced delays.

PubMed

Tang, Xiaoming; Qu, Hongchun; Wang, Ping; Zhao, Meng

2015-03-01

This paper investigates the off-line synthesis approach of model predictive control (MPC) for a class of networked control systems (NCSs) with network-induced delays. A new augmented model which can be readily applied to time-varying control law, is proposed to describe the NCS where bounded deterministic network-induced delays may occur in both sensor to controller (S-A) and controller to actuator (C-A) links. Based on this augmented model, a sufficient condition of the closed-loop stability is derived by applying the Lyapunov method. The off-line synthesis approach of model predictive control is addressed using the stability results of the system, which explicitly considers the satisfaction of input and state constraints. Numerical example is given to illustrate the effectiveness of the proposed method. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Wide band continuous all-fiber comb generator at 1.5 micron

NASA Astrophysics Data System (ADS)

Lemaître, François; Mondin, Linda; Orlik, X.

2017-11-01

We present an all-fiber continuous optical frequency comb-generator (OFCG) able to generate over 6 nm (750 GHz) at 1560 nm using a combination of electro-optic and acousto-optic modulations. As opposed to numerous experimental setups that use the longitudinal modes of an optical cavity to generate continuous optical frequency combs, our setup doesn't need any active stabilization of the cavity length since we use the intrinsically high stability of radiofrequency sources to generate the multiple lines of the comb laser. Moreover, compared to the work of ref [1], the hybrid optical modulation we use allows to suppress the problem of instability due interferences between the generated lines. We notice that these lines benefit from the spectral quality of the seed laser because the spectral width of the synthesized hyperfrequency and radiofrequency signals are generally narrower than laser sources.

Far infrared maser communications technology

NASA Technical Reports Server (NTRS)

Claspy, P. C.; Pao, Y. H.

1975-01-01

An optically pumped FIR laser was constructed and tested. Optimum operating conditions were determined with CH3OH as the lasing medium. The laser was found to operate equally well with flowing gas or in a sealed off configuration. The FIR cavity stability and pump laser stability were found to have significant problems. The absorption coefficient per unit pressure of 1-1 difluoroethylene at the P(22) and P(24) lines of the 10.4 micron CO2 band was measured. The FIR line pumped by P(22) occurs at approximately 890 microns, which may be in an atmospheric transmission window. It was found that significant Stark tuning of absorption lines of methanol and 1-1 difluoroethylene can be accomplished, even at the usual 100 to 300 mTorr operating pressures of FIR lasers. This means that the use of Stark tuning may enable more effective use of pump laser output.

Synthesis and biological evaluation of a series of non-hemiacetal ester derivatives of artemisinin.

PubMed

Zuma, Nonkululeko H; Smit, Frans J; de Kock, Carmen; Combrinck, Jill; Smith, Peter J; N'Da, David D

2016-10-21

In an attempt to improve the efficacy and stability of current, clinically used artemisinins, a series non-hemiacetal ester derivatives of artemisinin were synthesized and evaluated for their in vitro antiplasmodial and anticancer activities as well as cytotoxicities. These esters were synthesized through the reaction of acid anhydrides, or acid chlorides with artemisinin derived alcohol. In vitro antiplasmodial activity assessments were conducted against intraerythrocytic NF54 and Dd2 Plasmodium falciparum strains. Cytotoxicities were assessed, using normal human fetal lung fibroblast (WI-38) and Chinese hamster ovarian (CHO) mammalian cell lines, while anticancer activities were tested by using panels with three cell lines, consisting of renal (TK10), melanoma (UACC62) and breast (MCF7) cancer cells. Most compounds were found active against the breast cancer cell line. Since antiplasmodial activities for most compounds were found comparable only to that of artesunate, this study did not yield any esters with significantly improved antimalarial efficacies, nor did it deliver any promising antitumor hits. However, from the outcomes of this study, compounds with good safety profiles and increased thermal stabilities, compared to the clinically used artemisinins, were identified. The benzoate derivative 11 was found to have antimalarial activity, comparable to that of dihydroartemisinin and was it subsequently identified as a candidate for further investigation in the urgent search for new, safe and effective antimalarial drugs. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

ME-143 Is Superior to Genistein in Suppression of WNT Signaling in Colon Cancer Cells.

PubMed

Pintova, Sofya; Planutis, Kestutis; Planutiene, Marina; Holcombe, Randall F

2017-04-01

This study tested the effect of the soy isoflavones genistein and ME-143, and two chemotherapeutic agents, 5-fluorouracil (5FU) and oxaliplatin, on WNT signaling. Colon cancer cell lines RKO (hereditary nonpolyposis colorectal cancer type) and DLD1 (most common colorectal cancer type driven by a mutation in WNT pathway) were utilized. WNT throughput was measured using a β-catenin-responsive SuperTopFlash luciferase assay. A stabilized β-catenin construct was employed to test β-catenin involvement in the mechanism of drug activity. ME-143 was a more than 10-fold potent inhibitor of DLD1 proliferation than genistein at 3.125 μM. Genistein alone did not inhibit WNT signaling in either cell line. In RKO cells, oxaliplatin and its combination with 5FU significantly inhibited WNT throughput. Neither 5FU, oxaliplatin nor their combination inhibited WNT signaling in DLD1 cells. In both the RKO and DLD1 cell lines, ME-143 significantly reduced WNT throughput by 65-75%. The introduction of stabilized β-catenin attenuated the ME-143-dependent inhibition of the WNT/β-catenin pathway. ME-143 alone and in combination with 5FU and oxaliplatin effectively inhibits the WNT/β-catenin pathway in colorectal cancer cells of diverse genetic background. β-Catenin is directly involved in the mechanism of inhibition, and clinical studies are warranted. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Mitigation of landslide area around railway tunnel, South Sumatra Province, Indonesia

NASA Astrophysics Data System (ADS)

Toha, M. Taufik; Setiabudidaya, Dedi; Komar, Syamsul; Bochori, Ghadafi, Moamar A.; Adiwarman, Mirza; Rahim, S. E.

2017-09-01

Adequate and safe railway line infrastructures as well as facilities are required to support the rail transport system in South Sumatra. The slope stability along railway line of Lahat-Lubuk Linggau South Sumatra were studied during landslide that occured on January 23th, 2016. The landslide occurred on the mouth of railway tunnel in Gunung Gajah Village, Lahat District that causing the railway transportation system had to be stopped for a few days. A comprehensive research was conducted to analyze the causes of the landslide and to identify other landslide risky areas along the railway line Lahat-Lubuk Linggau. The research activities included surveying, sampling, laboratory testing, investigating condition of geology, geotechnics, hydrogeology/hydrology, morphology and land use. The factors that cause landslide in the past studies were found to be morphology, structural geology, physical and mechanical characteristics, hydrogeology, hydrology, external forces (train vibration, earthquake). Results back analysis of slope stability when the landslide occurred showed that the value Safety Factor (SF) = 1, angle of friction = 0°, and cohesion = 0.49 kg/cm2 (49 kPa). Based on the observation and analysis of the condition of the morphology and orientation of the structure of the rock layers, there was a location prone to landslide (labile) in the surrounding area of the landslide. Mitigations to potential landslide in adjacent area were building a retaining wall, draining channels, and shortcrete at the rock wall after landslides and maintaining the land use around the slopes.

Effects of various gate materials on electrical degradation of a-Si:H TFT in industrial display application

NASA Astrophysics Data System (ADS)

Ho, Ching-Yuan; Chang, Yaw-Jen

2016-02-01

Both aluminum (Al) and copper (Cu), acting as transmission lines in the hydrogenated amorphous silicon of a thin film transistor (a-Si:H TFT), were studied to investigate electrical degradation including electron-migration (EM) and threshold voltage (Vt) stability and recovery performance. Under long-term current stress, the Cu material exhibited excellent resistance to EM properties, but a passivated SiNx crack was observed due to fast heat conductivity. By applying electrical stress on the gate and drain for 5 × 104 s, the power-law time dependency of the threshold voltage shift (ΔVt) indicated that the defective state creation dominated the TFT device's instability. The presence of drain stress increased the overall ΔVt because the high longitudinal field induced impact ionization and then, enhanced hot-carrier-induced electron trapping within the gate SiNx dielectric. An annealing effect prompted a stressed a-Si:H TFT back to virgin status. This study proposes better ΔVt stability and excellent resistance against electron-migration in a Cu gate device which can be considered as a candidate for a transmission line on prolonged TFT applications.

Long-Circulating Curcumin-Loaded Liposome Formulations with High Incorporation Efficiency, Stability and Anticancer Activity towards Pancreatic Adenocarcinoma Cell Lines In Vitro.

PubMed

Mahmud, Mohamed; Piwoni, Adriana; Filipczak, Nina; Janicka, Martyna; Gubernator, Jerzy

2016-01-01

The incorporation of hydrophobic drugs into liposomes improve their bioavailability and leads to increased stability and anticancer activity, along with decreased drug toxicity. Curcumin (Cur) is a natural polyphenol compound with a potent anticancer activity in pancreatic adenocarcinoma (PA). In the present study, different types of Cur-loaded liposomal formulations were prepared and characterized in terms of size, shape, zeta potential, optimal drug-to-lipid ratio and stability at 4°C, 37°C; and in human plasma in vitro. The best formulation in terms of these parameters was PEGylated, cholesterol-free formulation based upon hydrogenated soya PC (HSPC:DSPE-PEG2000:Cur, termed H5), which had a 0.05/10 molar ratio of drug-to-lipid, was found to be stable and had a 96% Cur incorporation efficiency. All Cur-loaded liposomal formulations had potent anticancer activity on the PA cancer cell lines AsPC-1 and BxPC-3, and were less toxic to a normal cell line (NHDF). Furthermore, apoptosis-induction induced by Cur in PA cells was associated with morphological changes including cell shrinkage, cytoplasmic blebbing, irregularity in shape and the externalization of cell membrane phosphatidylserine, which was preceded by an increase in intracellular reactive oxygen species (ROS) generation and caspase 3/7 activation. Because the liposomal formulations tested here, especially the H5 variant which exhibited slow release of the Cur in the human plasma test, the formulation may be stable enough to facilitate the accumulation of pharmacologically active amounts of Cur in target cancer tissue by EPR. Therefore, our formulations could serve as a promising therapeutic approach for pancreatic cancer and other cancers.

Temporal, thermal, and light stability of continuously tunable cholesteric liquid crystal laser array.

PubMed

Jeong, Mi-Yun; Chung, Ki Soo; Wu, Jeong Weon

2014-11-01

Fine-structured polymerized cholesteric liquid crystal (PCLC) wedge laser devices have been realized, with high fine spatial tunability of the lasing wavelength. With resolution less than 0.3 nm in a broad spectral range, more than one hundred laser lines could be obtained in a PCLC cell without extra devices. For practical device application, we studied the stability of the device in detail over time, and in response to strong external light sources, and thermal perturbation. The PCLC wedge cells had good temporal stability for 1 year and showed good stability for strong perturbations, with the lasing wavelength shifting less than 1 nm, while the laser peak intensities decreased by up to 34%, and the high energy band edge of the photonic band gap (PBG) was red shifted 3 nm by temperature perturbation. However, when we consider the entire lasing spectrum for the PCLC cell, the 1-nm wavelength shift may not matter. Although the laser peak intensities were decreased by up to 34% in total for all of the perturbation cases, the remaining 34% laser peak intensity is considerable extent to make use. This good stability of the PCLC laser device is due to the polymerization of the CLC by UV curing. This study will be helpful for practical CLC laser device development.

Linear Dimensional Stability of Irreversible Hydrocolloid Materials Over Time.

PubMed

Garrofé, Analía B; Ferrari, Beatriz A; Picca, Mariana; Kaplan, Andrea E

2015-12-01

The aim of this study was to evaluate the linear dimensional stability of different irreversible hydrocolloid materials over time. A metal mold was designed with custom trays made of thermoplastic sheets (Sabilex, sheets 0.125 mm thick). Perforations were made in order to improve retention of the material. Five impressions were taken with each of the following: Kromopan 100 (LASCOD) [AlKr], which has dimensional stability of 100 hours, and Phase Plus (ZHERMACK) [AlPh], which has dimensional stability of 48 hours. Standardized digital photographs were taken at different time intervals (0, 15, 30, 45, 60, 120 minutes; 12, 24 and 96 hours), using an "ad-hoc" device. The images were analyzed with software (UTHSCSA Image Tool) by measuring the distance between intersection of the lines previously made at the top of the mold. The results were analyzed by ANOVA for repeated measures. Initial and final values were (mean and standard deviation): AlKr: 16.44 (0.22) and 16.34 (0.11), AlPh: 16.40 (0.06) and 16.18 (0.06). Statistical evaluation showed significant effect of material and time factors. Under the conditions in this study, time significantly affects the linear dimensional stability of irreversible hydrocolloid materials. Sociedad Argentina de Investigación Odontológica.

Wave packet dynamics, time scales and phase diagram in the IBM-Lipkin-Meshkov-Glick model

NASA Astrophysics Data System (ADS)

Castaños, Octavio; de los Santos, Francisco; Yáñez, Rafael; Romera, Elvira

2018-02-01

We derive the phase diagram of a scalar two-level boson model by studying the equilibrium and stability properties of its energy surface. The plane of control parameters is enlarged with respect to previous studies. We then analyze the time evolution of wave packets centered around the ground state at various quantum phase transition boundary lines. In particular, classical and revival times are computed numerically.

Puroindoline genes introduced into durum wheat reduce milling energy and change milling behavior similar to soft common wheats

USDA-ARS?s Scientific Manuscript database

Grain physical characteristics and milling behavior of a durum wheat line in which both wild-type puroindoline alleles were translocated and stabilized after backcrossing (Svevo-Pin) were compared with the parent line (Svevo). The only observed differences between grain characteristics were the mech...

Comparative study between REAP 200 and FEP171 CAR with 50-kV raster e-beam system for sub-100-nm technology

NASA Astrophysics Data System (ADS)

Baik, Ki-Ho; Lem, Homer Y.; Dean, Robert L.; Osborne, Stephen; Mueller, Mark; Abboud, Frank E.

2003-08-01

In this paper, a process established with a positive-tone chemically amplified resist (CAR) from TOK REAP200 and Fujifilm Arch FEP171 and 50kV MEBES system is discussed. This TOK resist is developed for raster scan 50 kV e-beam systems. It has high contrast, good coating characteristics, good dry etch selectivity, and high environmental stability. In the mask industries, the most popular positive tone CAR is FEP171, which is a high activation energy type CAR. REAP (Raster E-beam Advanced Process) 200 is low activation energy type and new acetal protecting polymer. In this study, we compared to these different type resists in terms of contrast, PAB and PEB latitude, resist profile, footing, T-topping, PED stability, LER, Global CDU (Critical Dimension Uniformity) and resolution. The REAP200 Resist obtained 75nm isolated lines and spaces, 90nm dense patterns with vertical profile, and a good stability of delay time.

Experimental Verification of the Kruskal-Shafranov Stability Limit in Line-Tied Partial Toroidal Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oz, E.; Myers, C. E.; Yamada, M.

2011-07-19

The stability properties of partial toroidal flux ropes are studied in detail in the laboratory, motivated by ubiquitous arched magnetic structures found on the solar surface. The flux ropes studied here are magnetized arc discharges formed between two electrodes in the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys. Plasmas, 4, 1936 (1997)]. The three dimensional evolution of these flux ropes is monitored by a fast visible light framing camera, while their magnetic structure is measured by a variety of internal magnetic probes. The flux ropes are consistently observed to undergo large-scale oscillations as a result of an external kinkmore » instability. Using detailed scans of the plasma current, the guide field strength, and the length of the flux rope, we show that the threshold for kink stability is governed by the Kruskal-Shafranov limit for a flux rope that is held fixed at both ends (i.e., qa = 1).« less

Experimental verification of the Kruskal-Shafranov stability limit in line-tied partial-toroidal plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oz, E.; Myers, C. E.; Yamada, M.

2011-10-15

The stability properties of partial-toroidal flux ropes are studied in detail in the laboratory, motivated by ubiquitous arched magnetic structures found on the solar surface. The flux ropes studied here are magnetized arc discharges formed between two electrodes in the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys. Plasmas 4, 1936 (1997)]. The three dimensional evolution of these flux ropes is monitored by a fast visible light framing camera, while their magnetic structure is measured by a variety of internal magnetic probes. The flux ropes are consistently observed to undergo large-scale oscillations as a result of an external kink instability.more » Using detailed scans of the plasma current, the guide field strength, and the length of the flux rope, we show that the threshold for kink stability is governed by the Kruskal-Shafranov limit for a flux rope that is held fixed at both ends (i.e., q{sub a} = 1).« less

Oridonin stabilizes retinoic acid receptor alpha through ROS-activated NF-κB signaling.

PubMed

Cao, Yang; Wei, Wei; Zhang, Nan; Yu, Qing; Xu, Wen-Bin; Yu, Wen-Jun; Chen, Guo-Qiang; Wu, Ying-Li; Yan, Hua

2015-04-10

Retinoic acid receptor alpha (RARα) plays an essential role in the regulation of many biological processes, such as hematopoietic cell differentiation, while abnormal RARα function contributes to the pathogenesis of certain diseases including cancers, especially acute promyelocytic leukemia (APL). Recently, oridonin, a natural diterpenoid isolated from Rabdosia rubescens, was demonstrated to regulate RARα by increasing its protein level. However, the underlying molecular mechanism for this action has not been fully elucidated. In the APL cell line, NB4, the effect of oridonin on RARα protein was analyzed by western blot and real-time quantitative RT-PCR analyses. Flow cytometry was performed to detect intracellular levels of reactive oxygen species (ROS). The association between nuclear factor-kappa B (NF-κB) signaling and the effect of oridonin was assessed using specific inhibitors, shRNA gene knockdown, and immunofluorescence assays. In addition, primary leukemia cells were treated with oridonin and analyzed by western blot in this study. RARα possesses transcriptional activity in the presence of its ligand, all-trans retinoic acid (ATRA). Oridonin remarkably stabilized the RARα protein, which retained transcriptional activity. Oridonin also moderately increased intracellular ROS levels, while pretreatment with the ROS scavenger, N-acetyl-l-cysteine (NAC), dramatically abrogated RARα stabilization by oridonin. More intriguingly, direct exposure to low concentrations of H2O2 also increased RARα protein but not mRNA levels, suggesting a role for ROS in oridonin stabilization of RARα protein. Further investigations showed that NAC antagonized oridonin-induced activation of NF-κB signaling, while the NF-κB signaling inhibitor, Bay 11-7082, effectively blocked the oridonin increase in RARα protein levels. In line with this, over-expression of IκΒα (A32/36), a super-repressor form of IκΒα, or NF-κB-p65 knockdown inhibited oridonin or H2O2-induced RARα stability. Finally, tumor necrosis factor alpha (TNFα), a classical activator of NF-κB signaling, modulated the stability of RARα protein. Oridonin stabilizes RARα protein by increasing cellular ROS levels, which causes activation of the NF-κB signaling pathway.

A comparative evaluation of dimensional stability of three types of interocclusal recording materials-an in-vitro multi-centre study

PubMed Central

2012-01-01

Background The introduction of different interocclusal recording materials has put clinicians in dilemma that which material should be used in routine clinical practice for precise recording and transferring of accurate existing occlusal records for articulation of patient’s diagnostic or working casts in the fabrication of good satisfactory prosthesis. In the era of developing world of dentistry the different materials are introduced for interocclusal record with different brand names because of this; the utility of the material is confusing for successful delivery of prosthesis with lack of in vitro or in vivo studies which will predict the property of the material with utility recommendations. Purpose of the study The aim of this multicenter research is to evaluate the time dependent linear dimensional stability of three types of interocclusal recording materials; which gives very clear idea to clinicians in regard to its usage in routine practice and recommendations for usage of the different materials. Also to find out ideal time for articulation of three types of interocclusal recording materials with accuracy. Materials and method Commercially available and ADA approved Polyether bite registration paste (Ramitec), Poly vinyl siloxane bite registration paste (Jetbite) and Zinc oxide eugenol (ZOE) bite registration paste (Super bite) were used in the study. A stainless steel die was made according to modified American dental Associations (ADA) specification no. 19. Each one of the tested materials were manipulated according to manufacturers’ instructions. The materials separated from die, 3-mins after their respective setting time, resulted in disks of standard diameter. Two parallel lines and three perpendicular lines reproduced on the surface. The distance between two parallel lines was measured at different time intervals i.e. 1 hour, 24, 48 and 72 hours by using travelling microscope (magnus) and compared with standard die measurements made according to ADA specification no.19 to find out the dimensional stability of these interocclusal recording materials. Total 120 samples were made for observation and results were subjected to statistical analysis. Statistical analysis was performed using analysis of variance (ANOVA) and then Tukey’s Honestly Significant Difference (HSD) test for comparison among groups at the 0.05 level of significance. After statistical analysis of the data, results were obtained and analyzed for interpretation. Results The results shows significant difference between the dimensional stability of all three material at different intervals with p-value <0.05. Comparatively the polyether bite registration material showed less distortion with good dimensional stability compared to Poly vinyl siloxane bite (Jetbite), Zinc oxide eugenol(ZOE) bite (Super bite) at 1 hour, 24, 48, and 72 hours. Conclusion The dimensional stability decreased with increase in time and is influenced by both material factor and time factor. Polyether was found to be more dimensionally stable interocclusal recording material, which was followed by Silicone and Zinc oxide eugenol (ZOE). The dimensional stability of Polyether was good. Zinc oxide eugenol is dimensionally more unstable when compared with polyether and polyvinyl siloxane. We recommend that the polyether interocclusal records must be articulated within 48 hours and Polyvinylsiloxane interocclusal records must be articulated within 24 hours and the ZOE should be articulated within 1 hour to get a correct restoration to have very minimum distortion and maximum satisfaction without failure of prosthesis. PMID:23039395

Atlantis OMS Pods and Vertical Stabilizer

NASA Image and Video Library

2011-07-09

S135-E-006375 (9 July 2011) --- Without the sun's being temporarily available to highlight space shuttle Atlantis' cargo bay and vertical stabilizer, the spacecraft barely shows through as a silhouette in this image photographed from the aft flight deck. The thin blue line of Earth?s atmosphere is the dominant feature in the photo. Photo credit: NASA

First-principles studies of chromium line-ordered alloys in a molybdenum disulfide monolayer

NASA Astrophysics Data System (ADS)

Andriambelaza, N. F.; Mapasha, R. E.; Chetty, N.

2017-08-01

Density functional theory calculations have been performed to study the thermodynamic stability, structural and electronic properties of various chromium (Cr) line-ordered alloy configurations in a molybdenum disulfide (MoS2) hexagonal monolayer for band gap engineering. Only the molybdenum (Mo) sites were substituted at each concentration in this study. For comparison purposes, different Cr line-ordered alloy and random alloy configurations were studied and the most thermodynamically stable ones at each concentration were identified. The configurations formed by the nearest neighbor pair of Cr atoms are energetically most favorable. The line-ordered alloys are constantly lower in formation energy than the random alloys at each concentration. An increase in Cr concentration reduces the lattice constant of the MoS2 system following the Vegard’s law. From density of states analysis, we found that the MoS2 band gap is tunable by both the Cr line-ordered alloys and random alloys with the same magnitudes. The reduction of the band gap is mainly due to the hybridization of the Cr 3d and Mo 4d orbitals at the vicinity of the band edges. The band gap engineering and magnitudes (1.65 eV to 0.86 eV) suggest that the Cr alloys in a MoS2 monolayer are good candidates for nanotechnology devices.

Design and synthesis of dimethylaminomethyl-substituted curcumin derivatives/analogues: potent antitumor and antioxidant activity, improved stability and aqueous solubility compared with curcumin.

PubMed

Fang, Xubin; Fang, Lei; Gou, Shaohua; Cheng, Lin

2013-03-01

A series of dimethylaminomethyl-substituted curcumin derivatives/analogues were designed and synthesized. All compounds effectively inhibited HepG2, SGC-7901, A549 and HCT-116 tumor cell lines proliferation in MTT assay. Particularly, compounds 2a and 3d showed much better activity than curcumin against all of the four tumor cell lines. Antioxidant test revealed that these compounds had higher free radical scavenging activity than curcumin towards both DPPH and galvinoxyl radicals. Furthermore, the aqueous solubility and stability of the target compounds were also significantly improved compared with curcumin. Copyright © 2013 Elsevier Ltd. All rights reserved.

A widely tunable 10-μm quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sow, P. L. T.; Mejri, S.; Tokunaga, S. K.

2014-06-30

We report the coherent phase-locking of a quantum cascade laser (QCL) at 10-μm to the secondary frequency standard of this spectral region, a CO{sub 2} laser stabilized on a saturated absorption line of OsO{sub 4}. The stability and accuracy of the standard are transferred to the QCL resulting in a line width of the order of 10 Hz, and leading to the narrowest QCL to date. The locked QCL is then used to perform absorption spectroscopy spanning 6 GHz of NH{sub 3} and methyltrioxorhenium, two species of interest for applications in precision measurements.

Microchannel plate life testing for UV spectroscopy instruments

NASA Astrophysics Data System (ADS)

Darling, N. T.; Siegmund, O. H. W.; Curtis, T.; McPhate, J.; Tedesco, J.; Courtade, S.; Holsclaw, G.; Hoskins, A.; Al Dhafri, S.

2017-08-01

The Emirates Mars Mission (EMM) UV Spectrograph (EMUS) is a far ultraviolet (102 nm to 170 nm) imaging spectrograph for characterization of the Martian exosphere and thermosphere. Imaging is accomplished by a photon counting open-face microchannel plate (MCP) detector using a cross delay line (XDL) readout. An MCP gain stabilization ("scrub") followed by lifetime spectral line burn-in simulation has been completed on a bare MCP detector at SSL. Gain and sensitivity stability of better than 7% has been demonstrated for total dose of 2.5 × 1012 photons cm-2 (2 C · cm-2 ) at 5.5 kHz mm-2 counting rates, validating the efficacy of an initial low gain full-field scrub.

Visual outcome of laser treatment in diabetic macular edema: Study from an Urban Diabetes Care Center.

PubMed

Alvi, Rashid; Memon, Muhammad Saleh; Shera, Samad; Mumtaz, Seema N; Shaikh, Sikander Ali; Fahim, Muhammad Faisal

2016-01-01

To determine the visual outcome of laser treatment in clinically significant macular edema. This interventional and qausi experimental study was carried out at Diabetic Association of Pakistan (DAP) during January 2011 and December 2012. Approval was taken from Research Ethical Committee of Isra Postgraduate Institute of Ophthalmology. Records of 925 eyes of 464 patients with "Clinical Significant macular edema" (CSME), treated with laser photocoagulation were analyzed. Best-corrected visual acuity (BCVA) at the time of presentation and at the last follow up, minimum of one year and maximum of 45 months was recorded and compared. SPSS version 20.0 was used to analyze the data. Diabetic retinopathy was found in 20.3% (1777) of 8742 diabetic attending DAP Hospital" amongst whom 39.6% (705) had Sight threatening diabetic retinopathy. Laser was advised in 96.4% (680) individuals, accepted by 70.5% (480) individuals. Amongst 960 eyes of 480 patients who accepted laser, 925 eyes had clinically significant macular edema and 35 eyes had PDR who are not included in this study. Amongst 925 eyes with CSME, Grid laser was done in 913 eyes (99%) and focal laser was done in 12 eyes (1%). After a follow up of 12 to 45 months, it was found that best corrected visual acuity had declined in 2.4% (22) eyes, stabilized in 67% (619) eyes and improved in 30.7% (284) eyes. One line improvement on Snellen's chart was fond in 21.3% (197) eyes, 2 lines in 8% (74) eyes, 3 lines in 1.2% (12) eyes and 4 lines in one (0.1%) eye with p-value of 0.000. Laser therapy is an effective treatment in stabilizing/improving the vision in diabetic macular edema particularly at those centers where only Argon Laser is available and OCF, FFA facilities do not exist.

Visual outcome of laser treatment in diabetic macular edema: Study from an Urban Diabetes Care Center

PubMed Central

Alvi, Rashid; Memon, Muhammad Saleh; Shera, Samad; Mumtaz, Seema N.; Shaikh, Sikander Ali; Fahim, Muhammad Faisal

2016-01-01

Objective: To determine the visual outcome of laser treatment in clinically significant macular edema. Methods: This interventional and qausi experimental study was carried out at Diabetic Association of Pakistan (DAP) during January 2011 and December 2012. Approval was taken from Research Ethical Committee of Isra Postgraduate Institute of Ophthalmology. Records of 925 eyes of 464 patients with “Clinical Significant macular edema” (CSME), treated with laser photocoagulation were analyzed. Best-corrected visual acuity (BCVA) at the time of presentation and at the last follow up, minimum of one year and maximum of 45 months was recorded and compared. SPSS version 20.0 was used to analyze the data. Results: Diabetic retinopathy was found in 20.3% (1777) of 8742 diabetic attending DAP Hospital” amongst whom 39.6% (705) had Sight threatening diabetic retinopathy. Laser was advised in 96.4% (680) individuals, accepted by 70.5% (480) individuals. Amongst 960 eyes of 480 patients who accepted laser, 925 eyes had clinically significant macular edema and 35 eyes had PDR who are not included in this study. Amongst 925 eyes with CSME, Grid laser was done in 913 eyes (99%) and focal laser was done in 12 eyes (1%). After a follow up of 12 to 45 months, it was found that best corrected visual acuity had declined in 2.4% (22) eyes, stabilized in 67% (619) eyes and improved in 30.7% (284) eyes. One line improvement on Snellen’s chart was fond in 21.3% (197) eyes, 2 lines in 8% (74) eyes, 3 lines in 1.2% (12) eyes and 4 lines in one (0.1%) eye with p-value of 0.000. Conclusion: Laser therapy is an effective treatment in stabilizing/improving the vision in diabetic macular edema particularly at those centers where only Argon Laser is available and OCF, FFA facilities do not exist. PMID:27882027

Realization of LOS (Line of Sight) stabilization based on reflector using carrier attitude compensation method

NASA Astrophysics Data System (ADS)

Mao, Yao; Tian, Jing; Ma, Jia-guang

2015-02-01

The techonology of LOS stabilization is widely applicated in moving carrier photoelectric systems such as shipborne, airborne and so on. In application situations with compact structure, such as LOS stabilization system of unmanned aerial vehicle, LOS stabilization based on reflector is adopted, and the detector is installed on the carrier to reduce the volume of stabilized platform and loading weight. However, the LOS deflection angle through reflector and the rotation angle of the reflector has a ratio relation of 2:1, simple reflector of stable inertial space can not make the optical axis stable. To eliminate the limitation of mirror stabilizing method, this article puts forward the carrier attitude compensation method, which uses the inertial sensor installed on the carrier to measure the attitude change of the carrier, and the stabilized platform rotating half of the carrier turbulence angle to realize the LOS stabilization.

Apparatus for simultaneously disreefing a centrally reefed clustered parachute system

DOEpatents

Johnson, Donald W.

1988-01-01

A single multi-line cutter is connected to each of a cluster of parachutes by a separate short tether line that holds the parachutes, initially reefed by closed loop reefing lines, close to one another. The closed loop reefing lines and tether lines, one from each parachute, are disposed within the cutter to be simultaneously cut by its actuation when a central line attached between the payload and the cutter is stretched upon deployment of the cluster. A pyrotechnic or electronic time delay may be included in the cutter to delay the actual simultaneous cutting of all lines until the clustered parachutes attain a measure of stability prior to being disreefed. A second set of reefing lines and second tether lines may be provided for each parachute, to enable a two-stage, separately timed, step-by-step disreefing.

Apparatus for simultaneously disreefing a centrally reefed clustered parachute system

DOEpatents

Johnson, D.W.

1988-06-21

A single multi-line cutter is connected to each of a cluster of parachutes by a separate short tether line that holds the parachutes, initially reefed by closed loop reefing lines, close to one another. The closed loop reefing lines and tether lines, one from each parachute, are disposed within the cutter to be simultaneously cut by its actuation when a central line attached between the payload and the cutter is stretched upon deployment of the cluster. A pyrotechnic or electronic time delay may be included in the cutter to delay the actual simultaneous cutting of all lines until the clustered parachutes attain a measure of stability prior to being disreefed. A second set of reefing lines and second tether lines may be provided for each parachute, to enable a two-stage, separately timed, step-by-step disreefing. 13 figs.

Change in collateral ligament length and tibiofemoral movement following joint line variation in TKA.

PubMed

Lin, Kun-Jhih; Wei, Hung-Wen; Huang, Chang-Hung; Liu, Yu-Liang; Chen, Wen-Chuan; McClean, Colin Joseph; Cheng, Cheng-Kung

2016-08-01

The primary intent of total knee arthroplasty is the restoration of normal knee kinematics, with ligamentous constraint being a key influential factor. Displacement of the joint line may lead to alterations in ligament attachment sites relative to knee flexion axis and variance of ligamentous constraints on tibiofemoral movement. This study aimed to investigate collaterals strains and tibiofemoral kinematics with different joint line levels. A previously validated knee model was employed to analyse the change in length of the collateral ligaments and tibiofemoral motion during knee flexion. The models shifted the joint line by 3 and 5 mm both proximally and distally from the anatomical level. The data were captured from full extension to flexion 135°. The elevated joint line revealed a relative increase in distance between ligament attachments for both collateral ligaments in comparison with the anatomical model. Also, tibiofemoral movement decreased with an elevation in the joint line. Conversely, lowering the joint line led to a significant decrease in distance between ligament attachments, but greater tibiofemoral motion. Elevation of the joint line would strengthen the capacity of collateral ligaments for knee motion constraint, whereas a distally shifted joint line might have the advantage of improving tibiofemoral movement by slackening the collaterals. It implies that surgeons can appropriately change the joint line position in accordance with patient's requirement or collateral tensions. A lowered joint line level may improve knee kinematics, whereas joint line elevation could be useful to maintain knee stability. V.

Statistical evaluation of stability data: criteria for change-over-time and data variability.

PubMed

Bar, Raphael

2003-01-01

In a recently issued ICH Q1E guidance on evaluation of stability data of drug substances and products, the need to perform a statistical extrapolation of a shelf-life of a drug product or a retest period for a drug substance is based heavily on whether data exhibit a change-over-time and/or variability. However, this document suggests neither measures nor acceptance criteria of these two parameters. This paper demonstrates a useful application of simple statistical parameters for determining whether sets of stability data from either accelerated or long-term storage programs exhibit a change-over-time and/or variability. These parameters are all derived from a simple linear regression analysis first performed on the stability data. The p-value of the slope of the regression line is taken as a measure for change-over-time, and a value of 0.25 is suggested as a limit to insignificant change of the quantitative stability attributes monitored. The minimal process capability index, Cpk, calculated from the standard deviation of the regression line, is suggested as a measure for variability with a value of 2.5 as a limit for an insignificant variability. The usefulness of the above two parameters, p-value and Cpk, was demonstrated on stability data of a refrigerated drug product and on pooled data of three batches of a drug substance. In both cases, the determined parameters allowed characterization of the data in terms of change-over-time and variability. Consequently, complete evaluation of the stability data could be pursued according to the ICH guidance. It is believed that the application of the above two parameters with their acceptance criteria will allow a more unified evaluation of stability data.

Farnesyltransferase inhibitor tipifarnib inhibits Rheb prenylation and stabilizes Bax in acute myelogenous leukemia cells

PubMed Central

Ding, Husheng; McDonald, Jennifer S.; Yun, Seongseok; Schneider, Paula A.; Peterson, Kevin L.; Flatten, Karen S.; Loegering, David A.; Oberg, Ann L.; Riska, Shaun M.; Huang, Shengbing; Sinicrope, Frank A.; Adjei, Alex A.; Karp, Judith E.; Meng, X. Wei; Kaufmann, Scott H.

2014-01-01

Although farnesyltransferase inhibitors have shown promising activity in relapsed lymphoma and sporadic activity in acute myelogenous leukemia, their mechanism of cytotoxicity is incompletely understood, making development of predictive biomarkers difficult. In the present study, we examined the action of tipifarnib in human acute myelogenous leukemia cell lines and clinical samples. In contrast to the Ras/MEK/ERK pathway-mediated Bim upregulation that is responsible for tipifarnib-induced killing of malignant lymphoid cells, inhibition of Rheb-induced mTOR signaling followed by dose-dependent upregulation of Bax and Puma occurred in acute myelogenous leukemia cell lines undergoing tipifarnib-induced apoptosis. Similar Bax and Puma upregulation occurred in serial bone marrow samples harvested from a subset of acute myelogenous leukemia patients during tipifarnib treatment. Expression of FTI-resistant Rheb M184L, like knockdown of Bax or Puma, diminished tipifarnib-induced killing. Further analysis demonstrated that increased Bax and Puma levels reflect protein stabilization rather than increased gene expression. In U937 cells selected for tipifarnib resistance, neither inhibition of signaling downstream of Rheb nor Bax and Puma stabilization occurred. Collectively, these results not only identify a pathway downstream from Rheb that contributes to tipifarnib cytotoxicity in human acute myelogenous leukemia cells, but also demonstrate that FTI-induced killing of lymphoid versus myeloid cells reflects distinct biochemical mechanisms downstream of different farnesylated substrates. (ClinicalTrials.gov identifier NCT00602771) PMID:23996484

Microencapsulation of islets within alginate/poly(ethylene glycol) gels cross-linked via Staudinger ligation

PubMed Central

Hall, Kristina K.; Gattás-Asfura, Kerim M.; Stabler, Cherie L.

2010-01-01

Functionalized alginate and PEG polymers were used to generate covalently linked alginate-PEG (XAlgPEG) microbeads of high stability. The cell-compatible Staudinger ligation scheme was used to chemoselectively cross-link phosphine-terminated poly(ethylene glycol) (PEG) to azide-functionalized alginate, resulting in XAlgPEG hydrogels. XAlgPEG microbeads were formed by co-incubation of the two polymers, followed by ionic cross-linking of the alginate using barium ions. The enhanced stability and gel properties of the resulting XAlgPEG microbeads, as well as the compatibility of these polymers for the encapsulation of islets and beta cells lines, were investigated. Our data show that XAlgPEG microbeads exhibit superior resistance to osmotic swelling compared to traditional barium cross-linked alginate (Ba-Alg) beads, with a 5-fold reduction in observed swelling, as well as resistance to dissolution via chelation solution. Diffusion and porosity studies found XAlgPEG beads to exhibit properties comparable to standard Ba-Alg. Our data found XAlgPEG microbeads to be highly cell compatible with insulinoma cell lines, as well as rat and human pancreatic islets, where the viability and functional assessment of cells within XAlgPEG were comparable to Ba-Alg controls. The remarkable improved stability, as well as demonstrated cellular compatibility, of XAlgPEG hydrogels makes them an appealing option for a wide variety of tissue engineering applications. PMID:20654745

Optical Frequency Stabilization and Optical Phase Locked Loops: Golden Threads of Precision Measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taubman, Matthew S.

Stabilization of lasers through locking to optical cavities, atomic transitions, and molecular transitions has enabled the field of precision optical measurement since shortly after the invention of the laser. Recent advances in the field have produced an optical clock that is orders of magnitude more stable than those of just a few years prior. Phase locking of one laser to another, or to a frequency offset from another, formed the basis for linking stable lasers across the optical spectrum, such frequency chains exhibiting progressively finer precision through the years. Phase locking between the modes within a femtosecond pulsed laser hasmore » yielded the optical frequency comb, one of the most beautiful and useful instruments of our time. This talk gives an overview of these topics, from early work through to the latest 1E-16 thermal noise-limited precision recently attained for a stable laser, and the ongoing quest for ever finer precision and accuracy. The issues of understanding and measuring line widths and shapes are also studied in some depth, highlighting implications for servo design for sub-Hz line widths.« less

Hygienic quality of traditional processing and stability of tomato (Lycopersicon esculentum) puree in Togo.

PubMed

Ameyapoh, Yaovi; de Souza, Comlan; Traore, Alfred S

2008-09-01

Microbiological and physicochemical qualities of a tomato (Lycopersicon esculentum) puree production line (ripe tomato, washing, cutting, pounding, bleaching, straining, bottling and pasteurization) and its preservation in Togo, West Africa, were studied using the HACCP method. Samples generated during the steps described previously were analyzed by determining sensory, chemical and microbiological characteristics. Samples were analyzed using MPN for coliform populations and plate count methodology for other bacteria. The microorganisms involved in spoilage of the opened products were moulds of genera Penicillium, Aspergillus, Fusarium, Geotrichum, Mucor and gram-positive Bacillus bacteria. The preserved tomato puree exhibited a pH value of 4.3, 90% water content, 0.98 water activity (aw) and an average ascorbic acid level of 27.3mg/100g. Results showed that the critical control point (CCP) of this tomato puree processing line is the pasteurization stage. The analysis of selected microbiological and physicochemical parameters during the preservation of bottled tomato puree indicated that this product was stable over 22 months at 29 degrees C. But the stability of the opened product stored at 29 degrees C did not exceed two months.

In situ preparation of water-soluble ginsenoside Rh2-entrapped bovine serum albumin nanoparticles: in vitro cytocompatibility studies.

PubMed

Singh, Priyanka; Kim, Yeon Ju; Singh, Hina; Ahn, Sungeun; Castro-Aceituno, Verónica; Yang, Deok Chun

2017-01-01

The present study investigates a simple and convenient one-step procedure for the preparation of bovine serum albumin (BSA)-Rh2 nanoparticles (NPs) at room temperature. In this work, ginsenoside Rh2 was entrapped within the BSA protein to form BSA-Rh2 NPs to enhance the aqueous solubility, stability, and therapeutic efficacy of Rh2. The physiochemical characterization by high-performance liquid chromatography, nuclear magnetic resonance, Fourier transform infrared spectroscopy, field emission transmission electron microscopy, dynamic light scattering, and thermogravimetric analysis confirmed that the prepared BSA-Rh2 NPs were spherical, highly monodispersed, and stable in aqueous systems. In addition, the stability of NPs in terms of different time intervals, pHs, and temperatures (20°C-700°C) was analyzed. The results obtained with different pHs showed that the synthesized BSA-Rh2 NPs were stable in the physiological buffer (pH 7.4) for up to 8 days, but degraded under acidic conditions (pH 5.0) representing the pH inside tumor cells. Furthermore, comparative analysis of the water solubility of BSA-Rh2 NPs and standard Rh2 showed that the BSA nanocarrier enhanced the water solubility of Rh2. Moreover, in vitro cytotoxicity assays including cell viability assays and morphological analyses revealed that Rh2-entrapped BSA NPs, unlike the free Rh2, demonstrated better in vitro cell viability in HaCaT skin cell lines and that BSA enhanced the anticancer effect of Rh2 in A549 lung cell and HT29 colon cancer cell lines. Additionally, anti-inflammatory assay of BSA-Rh2 NPs and standard Rh2 performed using RAW264.7 cells revealed decreased lipopolysaccharide-induced nitric oxide production by BSA-Rh2 NPs. Collectively, the present study suggests that BSA can significantly enhance the therapeutic behavior of Rh2 by improving its solubility and stability in aqueous systems, and hence, BSA-Rh2 NPs may potentially be used as a ginsenoside delivery vehicle in cancer and inflammatory cell lines.

LAD Dissertation Prize: Laboratory Identification of Magnetohydrodynamic Eruption Criteria in the Solar Corona

NASA Astrophysics Data System (ADS)

Myers, Clayton E.; Yamada, Masaaki; Ji, Hantao

2018-06-01

Ideal magnetohydrodynamic instabilities such as the kink and torus instabilities are believed to play an important role in driving storage-and-release eruptions in the solar corona. These instabilities act on long-lived, arched magnetic flux ropes that are line-tied to the solar surface. In spite of numerous observational and computational studies, the conditions under which these instabilities produce an eruption remain a subject of intense debate. In this paper, we use a line-tied, arched flux rope experiment to systematically study storage-and-release eruption mechanisms in the laboratory [1]. Thin in situ magnetic probes facilitate the study of both the equilibrium and the stability of these laboratory flux ropes. In particular, they permit the direct measurement of magnetic (J×B) forces, both in equilibrium [2] and during dynamic events [3, 4]. Regarding stability and eruptions, two major results are reported: First, a new stability regime is identified where torus-unstable flux ropes fail to erupt. In this ‘failed torus’ regime, the flux rope is torus-unstable but kink-stable. Under these conditions, a dynamic toroidal field tension force surges in magnitude and prevents the flux rope from erupting [3, 4]. This dynamic tension force, which is missing from existing eruption models, is generated by magnetic self-organization events within the line-tied flux rope. Second, a clear torus instability threshold is observed in the kink-unstable regime. This latter result, which is consistent with existing theoretical [5] and numerical [6] results, verifies the key role of the torus instability in driving flux rope eruptions in the solar corona.[1] C. E. Myers, Ph.D. Thesis, Princeton University (2015)[2] C. E. Myers et al., Phys. Plasmas 23, 112102 (2016)[3] C. E. Myers et al., Nature 528, 526 (2015)[4] C. E. Myers et al., Plasma Phys. Control. Fusion 59, 014048 (2017)[5] O. Olmedo & J. Zhang, Astrophys. J. 718, 433 (2010)[6] T. Török & B. Kliem, Astrophys. J. 630, L97 (2005)This research is supported by DoE Contract DE-AC02-09CH11466 and by the NSF/DoE Center for Magnetic Self-Organization (CMSO).

Field performance of transgenic citrus trees: assessment of the long-term expression of uidA and nptII transgenes and its impact on relevant agronomic and phenotypic characteristics.

PubMed

Pons, Elsa; Peris, Josep E; Peña, Leandro

2012-07-15

The future of genetic transformation as a tool for the improvement of fruit trees depends on the development of proper systems for the assessment of unintended effects in field-grown GM lines. In this study, we used eight transgenic lines of two different citrus types (sweet orange and citrange) transformed with the marker genes β-glucuronidase (uidA) and neomycin phosphotransferase II (nptII) as model systems to study for the first time in citrus the long-term stability of transgene expression and whether transgene-derived pleiotropic effects occur with regard to the morphology, development and fruit quality of orchard-grown GM citrus trees. The stability of the integration and expression of the transgenes was confirmed in 7-year-old, orchard-grown transgenic lines by Southern blot analysis and enzymatic assays (GUS and ELISA NPTII), respectively. Little seasonal variation was detected in the expression levels between plants of the same transgenic line in different organs and over the 3 years of analysis, confirming the absence of rearrangements and/or silencing of the transgenes after transferring the plants to field conditions. Comparisons between the GM citrus lines with their non-GM counterparts across the study years showed that the expression of these transgenes did not cause alterations of the main phenotypic and agronomic plant and fruit characteristics. However, when comparisons were performed between diploid and tetraploid transgenic citrange trees and/or between juvenile and mature transgenic sweet orange trees, significant and consistent differences were detected, indicating that factors other than their transgenic nature induced a much higher phenotypic variability. Our results indicate that transgene expression in GM citrus remains stable during long-term agricultural cultivation, without causing unexpected effects on crop characteristics. This study also shows that the transgenic citrus trees expressing the selectable marker genes that are most commonly used in citrus transformation were substantially equivalent to the non-transformed controls with regard to their overall agronomic performance, as based on the use of robust and powerful assessment techniques. Therefore, future studies of the possible pleiotropic effects induced by the integration and expression of transgenes in field-grown GM citrus may focus on the newly inserted trait(s) of biotechnological interest.

Field performance of transgenic citrus trees: Assessment of the long-term expression of uidA and nptII transgenes and its impact on relevant agronomic and phenotypic characteristics

PubMed Central

2012-01-01

Background The future of genetic transformation as a tool for the improvement of fruit trees depends on the development of proper systems for the assessment of unintended effects in field-grown GM lines. In this study, we used eight transgenic lines of two different citrus types (sweet orange and citrange) transformed with the marker genes β-glucuronidase (uidA) and neomycin phosphotransferase II (nptII) as model systems to study for the first time in citrus the long-term stability of transgene expression and whether transgene-derived pleiotropic effects occur with regard to the morphology, development and fruit quality of orchard-grown GM citrus trees. Results The stability of the integration and expression of the transgenes was confirmed in 7-year-old, orchard-grown transgenic lines by Southern blot analysis and enzymatic assays (GUS and ELISA NPTII), respectively. Little seasonal variation was detected in the expression levels between plants of the same transgenic line in different organs and over the 3 years of analysis, confirming the absence of rearrangements and/or silencing of the transgenes after transferring the plants to field conditions. Comparisons between the GM citrus lines with their non-GM counterparts across the study years showed that the expression of these transgenes did not cause alterations of the main phenotypic and agronomic plant and fruit characteristics. However, when comparisons were performed between diploid and tetraploid transgenic citrange trees and/or between juvenile and mature transgenic sweet orange trees, significant and consistent differences were detected, indicating that factors other than their transgenic nature induced a much higher phenotypic variability. Conclusions Our results indicate that transgene expression in GM citrus remains stable during long-term agricultural cultivation, without causing unexpected effects on crop characteristics. This study also shows that the transgenic citrus trees expressing the selectable marker genes that are most commonly used in citrus transformation were substantially equivalent to the non-transformed controls with regard to their overall agronomic performance, as based on the use of robust and powerful assessment techniques. Therefore, future studies of the possible pleiotropic effects induced by the integration and expression of transgenes in field-grown GM citrus may focus on the newly inserted trait(s) of biotechnological interest. PMID:22794278

Investigation on Stability in Roll of Square Section Missile at High Angle of Attack

NASA Astrophysics Data System (ADS)

Tao, Yang; Fan, Zhaolin; Wu, Jifei; Wu, Wenhua

An experimental investigation of the stability in roll of a square section missile at high incidence was conducted in FL-23 wind tunnel. Dynamic motions were obtained on a square section missile that is free to rotate about its longitudinal axis. Different dynamic rolling motions were observed depending on the incidence of the model sting. These dynamic regimes include damped oscillations, quasi-limit-cycle wing-rock motion, and constant rolling. A coupling numerical method was established by solving the fluid dynamics equations and the rigid-body dynamics equations synchronously in order to predict the onset and the development of uncommented motions and then explore the unsteady movement characteristics of the aircraft. The study indicates that the aircraft loss stability at high incidence is caused by the asymmetric vertex on the level fin tip liftoff and attach alternately. The computation results are in line with the experiment results.

MHD Stability in Compact Stellarators

NASA Astrophysics Data System (ADS)

Fu, Guoyong

1999-11-01

A key issue for current carrying compact stellarators(S.P. Hirshman et al., "Physics of compact stellarators", Phys. Plasmas 6, 1858 (1999).) is the stability of ideal MHD modes. We present recent stability results of external kink modes, ballooning mode, and vertical modes in Quasi-axisymmetric Stellarators (QAS)( A. Reiman et al, "Physics issue in the design of a high beta Quasi-Axisymmetric Stellarator" the 17th IAEA Fusion Energy conference, (Yokohama, Japan, October 1998), Paper ICP/06.) as well as Quasi-Omnigeneous Stellarators (QOS)^2. The 3D stability code Terpsichore(W. A. Cooper et al., Phys. Plasmas 3, 275 (1996)) is used in this study. The vertical stability in a current carrying stellarator is studied for the first time. The vertical mode is found to be stabilized by externally generated poloidal flux(G.Y. Fu et al., "Stability of vertical mode in a current carrying stellarator"., to be submitted). Physically, this is because the external poloidal flux enhances the field line bending energy relative to the current drive term in the MHD energy principle, δ W. A simple stability criteria is derived in the limit of large aspect ratio and constant current density. For wall at infinite distance from the plasma, the amount of external flux needed for stabilization is given by f=(κ^2-κ)/(κ^2+1) where κ is the axisymmetric elongation and f is the fraction of the external rotational transform at the plasma edge. A systematic parameter study shows that the external kink in QAS can be stabilized at high beta ( ~ 5%) without a conducting wall by combination of edge magnetic shear and 3D shaping(G. Y. Fu et al., "MHD stability calculations of high-beta Quasi-Axisymmetric Stellarators", the 17th IAEA Fusion Energy conference, (Yokohama, Japan, October 1998), paper THP1/07.). The optimal shaping is obtained by using an optimizer with kink stability included in its objective function. The physics mechanism for the kink modes is studied by examining relative contributions of individual terms in δ W. It is found the external kinks are mainly driven by the parallel current. The pressure contributes significantly to the overall drive through the curvature term and the Pfirsch-Schluter current. These results demonstrate potential of QAS and QOS for disruption-free operations at high-beta without a close-fitting conducting wall and feedback stabilization.

Ecological resilience in lakes and the conjunction fallacy.

PubMed

Spears, Bryan M; Futter, Martyn N; Jeppesen, Erik; Huser, Brian J; Ives, Stephen; Davidson, Thomas A; Adrian, Rita; Angeler, David G; Burthe, Sarah J; Carvalho, Laurence; Daunt, Francis; Gsell, Alena S; Hessen, Dag O; Janssen, Annette B G; Mackay, Eleanor B; May, Linda; Moorhouse, Heather; Olsen, Saara; Søndergaard, Martin; Woods, Helen; Thackeray, Stephen J

2017-11-01

There is a pressing need to apply stability and resilience theory to environmental management to restore degraded ecosystems effectively and to mitigate the effects of impending environmental change. Lakes represent excellent model case studies in this respect and have been used widely to demonstrate theories of ecological stability and resilience that are needed to underpin preventative management approaches. However, we argue that this approach is not yet fully developed because the pursuit of empirical evidence to underpin such theoretically grounded management continues in the absence of an objective probability framework. This has blurred the lines between intuitive logic (based on the elementary principles of probability) and extensional logic (based on assumption and belief) in this field.

Meiotic behavior as a selection tool in silage corn breeding.

PubMed

Souza, V F; Pagliarini, M S; Scapim, C A; Rodovalho, M; Faria, M V

2010-10-19

In breeding programs, commercial hybrids are frequently used as a source of inbred lines to obtain new hybrids. Considering that maize production is dependent on viable gametes, the selection of populations to obtain inbred lines with high meiotic stability could contribute to the formation of new silage corn hybrids adapted to specific region. We evaluated the meiotic stability of five commercial hybrids of silage corn used in southern Brazil with conventional squashing methods. All of them showed meiotic abnormalities. Some abnormalities, such as abnormal chromosome segregation and absence of cytokinesis, occurred in all the genotypes, while others, including cytomixis and abnormal spindle orientation, were found only in some genotypes. The hybrid SG6010 had the lowest mean frequency of abnormal cells (21.27%); the highest frequency was found in the hybrid P30K64 (44.43%). However, the frequency of abnormal meiotic products was much lower in most genotypes, ranging from 7.63% in the hybrid CD304 to 43.86% in Garra. Taking into account the percentage of abnormal meiotic products and, hence, meiotic stability, only the hybrids CD304, P30K64, SG6010, and P30F53 are recommended to be retained in the breeding program to obtain inbred lines to create new hybrids.

Post-translational modification and stability of low molecular weight cyclin E.

PubMed

Mull, B B; Cox, J; Bui, T; Keyomarsi, K

2009-09-03

Our laboratory has previously described the presence of five tumor-specific low molecular weight isoforms of cyclin E in both tumor cell lines and breast cancer patient biopsies. We have also shown that one of these low forms arises from an alternate start site, whereas the other four appear as two sets of doublets following cleavage through an elastase-like enzyme. However, the origin of both sets of doublets was unknown. Here, we demonstrate that the larger isoform of each doublet is the result of phosphorylation at a key degradation site. Through site-directed mutagenesis of different phosphorylation sites within the cyclin E protein, we discovered that phosphorylation of threonine 395 is responsible for generating the larger isoform of each doublet. Because phosphorylation of threonine 395 has been linked to the proteasome-mediated degradation of full length cyclin E, we examined the stability of T395A phospho-mutants in both non-tumorigenic mammary epithelial cells and tumor cells. The results revealed that the low molecular weight isoforms appear to be stable in both a tumor cell line and a non-tumor forming cell line regardless of the presence of this critical phosphorylation site. The stability of low molecular weight cyclin E may have implications for both tumorigenesis and treatment of tumors expressing them.

Stress distribution calculations through a snow slab of varying elastic modulus; comparison with stability evaluation in the field

NASA Astrophysics Data System (ADS)

Swinkels, Laura; Borstad, Chris

2017-04-01

Field observations are the main tools for assessing the snow stability concerning dry snow slab avalanche release. Often, theoretical studies cannot directly be translated into useful information for avalanche recreationists and forecasters in the field, and vice versa; field observations are not always objective and quantifiable for theoretical studies. Moreover, numerical models often simplify the snowpack and generally use an isotropic single layer slab which is not representative of the real-life situation. The aim of this study is to investigate the stress distribution in a snowpack with an elastic modulus that continuously varies with depth. The focus lies on the difference between a slab with a gradient in hardness and a slab with isotropic hardness and the effect on the calculated maximum stress and the stability evaluation in the field. Approximately 20 different snow pits were evaluated in the mountains around Tromsø, Norway and Longyearbyen, Svalbard. In addition to the standard snowpack observations, the hardness was measured using a thin-blade gauge. Extended column tests were executed for stability evaluation. Measurements from the field were used as input for stress calculations for each snow pit using a line load solution for a sloping half space with a non-homogeneous elastic modulus. The hardness measurements were used to calculate the elastic modulus and a power law relation was fit through the modulus in the slab. The calculated shear stress was compared to the estimated stability and character of the specific snowpack The results show that the approach used for this study improves the calculation of stress at a given depth, although many assumptions and simplifications were still needed. Comparison with the snow profiles indicate that calculated stresses correlate well with the observed snowpack properties and stability. The calculated shear stresses can be introduced in the standard stability index and give a better indication for the snowpack stability. Further research is required to delimit the stresses needed for propagation of a weak layer fracture.

76 FR 22928 - Nextera Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-25

... implementation. There would be no land use changes along transmission lines (no new lines would be required for...-term grid reliability and stability. Land use conditions would not change significantly PBNP, and there... result from the proposed EPU. Non-Radiological Impacts Land Use and Aesthetic Impacts Potential land use...

A general solution to the hidden-line problem. [to graphically represent aerodynamic stability derivatives

NASA Technical Reports Server (NTRS)

Hedgley, D. R., Jr.

1982-01-01

The requirements for computer-generated perspective projections of three dimensional objects has escalated. A general solution was developed. The theoretical solution to this problem is presented. The method is very efficient as it minimizes the selection of points and comparison of line segments and hence avoids the devastation of square-law growth.

The influence of lightning induced voltage on the distribution power line polymer insulators.

PubMed

Izadi, Mahdi; Abd Rahman, Muhammad Syahmi; Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

2017-01-01

Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance.

The influence of lightning induced voltage on the distribution power line polymer insulators

PubMed Central

Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

2017-01-01

Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance. PMID:28234930

Experimental study on distributed optical fiber-based approach monitoring saturation line in levee engineering

NASA Astrophysics Data System (ADS)

Su, Huaizhi; Li, Hao; Kang, Yeyuan; Wen, Zhiping

2018-02-01

Seepage is one of key factors which affect the levee engineering safety. The seepage danger without timely detection and rapid response may likely lead to severe accidents such as seepage failure, slope instability, and even levee break. More than 90 percent of levee break events are caused by the seepage. It is very important for seepage behavior identification to determine accurately saturation line in levee engineering. Furthermore, the location of saturation line has a major impact on slope stability in levee engineering. Considering the structure characteristics and service condition of levee engineering, the distributed optical fiber sensing technology is introduced to implement the real-time observation of saturation line in levee engineering. The distributed optical fiber temperature sensor system (DTS)-based monitoring principle of saturation line in levee engineering is investigated. An experimental platform, which consists of DTS, heating system, water-supply system, auxiliary analysis system and levee model, is designed and constructed. The monitoring experiment of saturation line in levee model is implemented on this platform. According to the experimental results, the numerical relationship between moisture content and thermal conductivity in porous medium is identified. A line heat source-based distributed optical fiber method obtaining the thermal conductivity in porous medium is developed. A DTS-based approach is proposed to monitor the saturation line in levee engineering. The embedment pattern of optical fiber for monitoring saturation line is presented.

Nonlinear neural control with power systems applications

NASA Astrophysics Data System (ADS)

Chen, Dingguo

1998-12-01

Extensive studies have been undertaken on the transient stability of large interconnected power systems with flexible ac transmission systems (FACTS) devices installed. Varieties of control methodologies have been proposed to stabilize the postfault system which would otherwise eventually lose stability without a proper control. Generally speaking, regular transient stability is well understood, but the mechanism of load-driven voltage instability or voltage collapse has not been well understood. The interaction of generator dynamics and load dynamics makes synthesis of stabilizing controllers even more challenging. There is currently increasing interest in the research of neural networks as identifiers and controllers for dealing with dynamic time-varying nonlinear systems. This study focuses on the development of novel artificial neural network architectures for identification and control with application to dynamic electric power systems so that the stability of the interconnected power systems, following large disturbances, and/or with the inclusion of uncertain loads, can be largely enhanced, and stable operations are guaranteed. The latitudinal neural network architecture is proposed for the purpose of system identification. It may be used for identification of nonlinear static/dynamic loads, which can be further used for static/dynamic voltage stability analysis. The properties associated with this architecture are investigated. A neural network methodology is proposed for dealing with load modeling and voltage stability analysis. Based on the neural network models of loads, voltage stability analysis evolves, and modal analysis is performed. Simulation results are also provided. The transient stability problem is studied with consideration of load effects. The hierarchical neural control scheme is developed. Trajectory-following policy is used so that the hierarchical neural controller performs as almost well for non-nominal cases as they do for the nominal cases. The adaptive hierarchical neural control scheme is also proposed to deal with the time-varying nature of loads. Further, adaptive neural control, which is based on the on-line updating of the weights and biases of the neural networks, is studied. Simulations provided on the faulted power systems with unknown loads suggest that the proposed adaptive hierarchical neural control schemes should be useful for practical power applications.

Evaluating plyometric exercises using time to stabilization.

PubMed

Ebben, William P; Vanderzanden, Tyler; Wurm, Bradley J; Petushek, Erich J

2010-02-01

Plyometric exercises are frequently used in strength and conditioning and rehabilitation programs because the landing phase of these exercises requires dynamic stabilization. This study examined the differences in landing stability of a variety of plyometric exercises by assessing time to stabilization (TTS), its reliability, and sex differences therein. Forty-nine men and women performed a variety of plyometric exercises thought to represent a continuum of difficulty of dynamic stabilization during landing. Plyometric exercises included line hops, cone hops, squat jumps, tuck jumps, countermovement jumps, dumbbell countermovement jumps, and single leg countermovement jumps, each performed for 3 repetitions on a force platform. A 2-way mixed analysis of covariance with repeated measures for plyometric exercise type was used to evaluate the main effects for plyometric exercise type and the interaction between plyometric exercise type and sex for TTS. Subject jumping ability was evaluated as a covariate. Results revealed significant main effects for plyometric exercise type (p < or = 0.001) and for the interaction between plyometric exercise type and sex (p = 0.002). Bonferroni adjusted post hoc analysis demonstrated differences in TTS between a number of plyometric exercises for men and women. Reliability analysis revealed intraclass correlation coefficients ranging from 0.51 to 0.86 with no significant difference between trials (p > 0.05). Practitioners who use plyometrics to train dynamic stability should create programs that progress the intensity of the exercises based on the results of this study. This study also demonstrated that TTS is moderately to highly reliable for a variety of jumping conditions for both men and women.

Second neighbors inducing common frequencies for bright and dark solitons

NASA Astrophysics Data System (ADS)

Tala-Tebue, E.; Djoufack, Z. I.; Kenfack-Jiotsa, A.; Kapche-Tagne, F.; Kofané, T. C.

2017-06-01

In this work, the dynamics of modulated waves in a modified Noguchi nonlinear electrical transmission line is studied with the contribution of second neighbors. It comes from this analysis that the line is governed by a dissipative nonlinear Schrödinger equation. One observes that the second neighbors counterbalance the effect of the linear capacitor CS in the frequency domains. The second neighbors well influence the line by increasing its bandwidth, its group velocity and the magnitude of the wave during its propagation. In the dispersion curve, we show that there exits a new region for the modulational instability/stability compared to the work of Pelap et al. (Phys. Rev. E 91, 022925 (2015)). The exactness of the analytical studies is accredited by numerical calculations. The most important feature of the new region, i.e. the second neighbors, is that the same frequency allows the use of either a bright soliton or a dark soliton depending on the choice of an appropriated wavelength.

Study on rejection characteristic of current loop to the base disturbance of optical communication system

NASA Astrophysics Data System (ADS)

Mao, Yao; Deng, Chao; Liu, Qiong; Cao, Zheng

2016-10-01

As laser has narrow transmitting beam and small divergence angle, the LOS (Line of Sight) stabilization of optical communication system is a primary precondition of laser communication links. Compound axis control is usually adopted in LOS stabilization of optical communication system, in which coarse tracking and fine tracking are included. Rejection against high frequency disturbance mainly depends on fine tracking LOS stabilization platform. Limited by different factors such as mechanical characteristic of the stabilization platform and bandwidth/noise of the sensor, the control bandwidth of LOS stabilization platform is restricted so that effective rejection of high frequency disturbance cannot be achieved as it mainly depends on the isolation characteristic of the platform itself. It is proposed by this paper that current loop may reject the effect of back-EMF. By adopting the method of electric control, high frequency isolation characteristic of the platform can be improved. The improvement effect is similar to increasing passive vibration reduction devices. Adopting the double closed loop control structure of velocity and current with the combining of the rejection effect of back-EMF caused by current loop is equivalent to reducing back-EMF coefficient, which can enhance the isolation ability of the LOS stabilization platform to high frequency disturbance.

Dynamic Control of Topological Defects in Artificial Colloidal Ice

DOE PAGES

Libál, A.; Nisoli, C.; Reichhardt, C.; ...

2017-04-05

We demonstrate the use of an external field to stabilize and control defect lines connecting topological monopoles in spin ice. For definiteness we perform Brownian dynamics simulations with realistic units mimicking experimentally realized artificial colloidal spin ice systems, and show how defect lines can grow, shrink or move under the action of direct and alternating fields. Asymmetric alternating biasing forces can cause the defect line to ratchet in either direction, making it possible to precisely position the line at a desired location. Such manipulation could be employed to achieve mobile information storage in these metamaterials.

Dynamic Control of Topological Defects in Artificial Colloidal Ice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libál, A.; Nisoli, C.; Reichhardt, C.

We demonstrate the use of an external field to stabilize and control defect lines connecting topological monopoles in spin ice. For definiteness we perform Brownian dynamics simulations with realistic units mimicking experimentally realized artificial colloidal spin ice systems, and show how defect lines can grow, shrink or move under the action of direct and alternating fields. Asymmetric alternating biasing forces can cause the defect line to ratchet in either direction, making it possible to precisely position the line at a desired location. Such manipulation could be employed to achieve mobile information storage in these metamaterials.

[About the infection of Drosophila female germ line cells by sigma virus (author's transl)].

PubMed

Brun, G

1977-01-01

The results which have been presented by Bregliano (1973) and Bregliano et Fleuriet (1975) in this "Annales" are discussed. The author's conclusion is that there are two distinct mechanisms for contamination of the cysts of non-stabilized females (in stabilized females, all cells, including oogonial cells, are infected in carrier state by sigma). Hypotheses are discussed.

Small satellite generic bus structure

NASA Astrophysics Data System (ADS)

Fiore, John N.; Summers, George D.

1993-02-01

A 'Smallsat' generic structure has been developed for LEO and expendable launch vehicles. The structure makes extensive use of Al-alloy honeycomb-stabilized panels in order to satisfy stiffness, weight, strength and thermal stability requirements in the LEO environment, in conjunction with discrete applications of multilayered insulation blankets and silverized Teflon radiators. The Smallsat structure is ideally suited for assembly-line manufacturing and storage until required.

Inclusion of methoxy groups inverts the thermodynamic stabilities of DNA-RNA hybrid duplexes: A molecular dynamics simulation study.

PubMed

Suresh, Gorle; Priyakumar, U Deva

2015-09-01

Modified nucleic acids have found profound applications in nucleic acid based technologies such as antisense and antiviral therapies. Previous studies on chemically modified nucleic acids have suggested that modifications incorporated in furanose sugar especially at 2'-position attribute special properties to nucleic acids when compared to other modifications. 2'-O-methyl modification to deoxyribose sugars of DNA-RNA hybrids is one such modification that increases nucleic acid stability and has become an attractive class of compounds for potential antisense applications. It has been reported that modification of DNA strands with 2'-O-methyl group reverses the thermodynamic stability of DNA-RNA hybrid duplexes. Molecular dynamics simulations have been performed on two hybrid duplexes (DR and RD) which differ from each other and 2'-O-methyl modified counterparts to investigate the effect of 2'-O-methyl modification on their duplex stability. The results obtained suggest that the modification drives the conformations of both the hybrid duplexes towards A-RNA like conformation. The modified hybrid duplexes exhibit significantly contrasting dynamics and hydration patterns compared to respective parent duplexes. In line with the experimental results, the relative binding free energies suggest that the introduced modifications stabilize the less stable DR hybrid, but destabilize the more stable RD duplex. Binding free energy calculations suggest that the increased hydrophobicity is primarily responsible for the reversal of thermodynamic stability of hybrid duplexes. Free energy component analysis further provides insights into the stability of modified duplexes. Copyright © 2015 Elsevier Inc. All rights reserved.

A new radiopharmaceutical compound (131I-PR81) for radioimmunotherapy of breast cancer: labeling of antibody and its quality control.

PubMed

Mohammadnejad, J; Rasaee, M J; Babaei, M H; Paknejad, M; Zahir, M H; Salouti, M; Rajabi, A Bitarafan; Mazidi, M

2010-01-01

PR81 is a monoclonal antibody that binds with high affinity to MUC1, which is over expressed on breast and other tumors. The objective of this study was to evaluate the application of this antibody against MUC1 as a radioimmunotherapeutical agent. Monoclonal antibody (PR81) against MUC1 was prepared, characterized, purified, and labeled with 131I. The immunoreactivity of radiolabeled mAb PR81with MUC1 (the native protein), BSA-P20 (a 20 amino acid corresponding the tandem repeat of MUC1) and MCF7 cell line were performed by RIA. In vitro stability of radiolabeled mAb in human serum was determined by thin layer chromatography (TLC). Cell toxicity and in vitro internalization studies were performed with the MCF7 cell line, and the tissue biodistribution of the radioiodinated PR81 was evaluated in normal BALB/c mice at 4, 24 and 48 hrs. The tumor imaging was performed in BALB/c mice with breast xenograft tumors at 24 and 72 hr after the complex injection. The labeling efficiency was found to be 59.9% ± 7.9%. MAb-131I conjugates showed high immunoreactivity towards MUC1 protein, BSA-P20 and MCF7 cell line. In vitro stability of the labeled product in human serum was found to be more than %50 over 24 hr. Cell toxicity and in vitro internalization studies showed that the mAb-131I conjugate inhibited 80% growth of the MCF7 cultured cell lines in vitro in a high concentration and up to %60 of the conjugate internalized after 24 h. Biodistribution studies were performed in normal BALB/c mice at 4, 24 and 48 hrs post-injection and no important accumulation was observed in vital organs. The tumors were visualized with high sensitivity after 24 and 72 hr in radioimmunoscintographical studies. These results show that the new radiopharmaceutical may be considered as a promising candidate for therapy of breast cancer.

DISTRIBUTED AMPLIFIER INCORPORATING FEEDBACK

DOEpatents

Bell, P.R. Jr.

1958-10-21

An improved distributed amplifier system employing feedback for stabilization is presented. In accordance with the disclosed invention, a signal to be amplified is applled to one end of a suitable terminated grid transmission line. At intervals along the transmission line, the signal is fed to stable, resistance-capacitance coupled amplifiers incorporating feedback loops therein. The output current from each amplifier is passed through an additional tube to minimize the electrostatic capacitance between the tube elements of the last stage of the amplifier, and fed to appropriate points on an output transmission line, similar to the grid line, but terminated at the opposite (input) end. The output taken from the unterminated end of the plate transmission line is proportional to the input voltage impressed upon the grid line.

Maintenance of Genetic Variability under Strong Stabilizing Selection: A Two-Locus Model

PubMed Central

Gavrilets, S.; Hastings, A.

1993-01-01

We study a two locus model with additive contributions to the phenotype to explore the relationship between stabilizing selection and recombination. We show that if the double heterozygote has the optimum phenotype and the contributions of the loci to the trait are different, then any symmetric stabilizing selection fitness function can maintain genetic variability provided selection is sufficiently strong relative to linkage. We present results of a detailed analysis of the quadratic fitness function which show that selection need not be extremely strong relative to recombination for the polymorphic equilibria to be stable. At these polymorphic equilibria the mean value of the trait, in general, is not equal to the optimum phenotype, there exists a large level of negative linkage disequilibrium which ``hides'' additive genetic variance, and different equilibria can be stable simultaneously. We analyze dependence of different characteristics of these equilibria on the location of optimum phenotype, on the difference in allelic effect, and on the strength of selection relative to recombination. Our overall result that stabilizing selection does not necessarily eliminate genetic variability is compatible with some experimental results where the lines subject to strong stabilizing selection did not have significant reductions in genetic variability. PMID:8514145

The HSOB GAIA: a cryogenic high stability cesic optical bench for missions requiring sub-nanometric optical stability

NASA Astrophysics Data System (ADS)

Courteau, Pascal; Poupinet, Anne; Kroedel, Mathias; Sarri, Giuseppe

2017-11-01

Global astrometry, very demanding in term of stability, requires extremely stable material for optical bench. CeSiC developed by ECM and Alcatel Alenia Space for mirrors and high stability structures, offers the best compromise in term of structural strength, stability and very high lightweight capability, with characteristics leading to be insensitive to thermo-elastic at cryogenic T°. The HSOB GAIA study realised by Alcatel Alenia Space under ESA contract aimed to design, develop and test a full scale representative High Stability Optical Bench in CeSiC. The bench has been equipped with SAGEIS-CSO laser metrology system MOUSE1, Michelson interferometer composed of integrated optics with a nm resolution. The HSOB bench has been submitted to an homogeneous T° step under vacuum to characterise the homothetic behaviour of its two arms. The quite negligible inter-arms differential measured with a nm range reproducibility, demonstrates that a complete 3D structure in CeSiC has the same CTE homogeneity as characterisation samples, fully in line with the GAIA need (1pm at 120K). This participates to the demonstration that CeSiC properties at cryogenic T° is fully appropriate to the manufacturing of complex highly stable optical structures. This successful study confirms ECM and Alcatel Alenia Space ability to define and manufacture monolithic lightweight highly stable optical structures, based on inner cells triangular design made only possible by the unique CeSiC manufacturing process.

Magneto-hydrodynamically stable axisymmetric mirrorsa)

NASA Astrophysics Data System (ADS)

Ryutov, D. D.; Berk, H. L.; Cohen, B. I.; Molvik, A. W.; Simonen, T. C.

2011-09-01

Making axisymmetric mirrors magnetohydrodynamically (MHD) stable opens up exciting opportunities for using mirror devices as neutron sources, fusion-fission hybrids, and pure-fusion reactors. This is also of interest from a general physics standpoint (as it seemingly contradicts well-established criteria of curvature-driven instabilities). The axial symmetry allows for much simpler and more reliable designs of mirror-based fusion facilities than the well-known quadrupole mirror configurations. In this tutorial, after a summary of classical results, several techniques for achieving MHD stabilization of the axisymmetric mirrors are considered, in particular: (1) employing the favorable field-line curvature in the end tanks; (2) using the line-tying effect; (3) controlling the radial potential distribution; (4) imposing a divertor configuration on the solenoidal magnetic field; and (5) affecting the plasma dynamics by the ponderomotive force. Some illuminative theoretical approaches for understanding axisymmetric mirror stability are described. The applicability of the various stabilization techniques to axisymmetric mirrors as neutron sources, hybrids, and pure-fusion reactors are discussed; and the constraints on the plasma parameters are formulated.

Calibration of high voltages at the ppm level by the difference of ^{83{m}}Kr conversion electron lines at the KATRIN experiment

NASA Astrophysics Data System (ADS)

Arenz, M.; Baek, W.-J.; Beck, M.; Beglarian, A.; Behrens, J.; Bergmann, T.; Berlev, A.; Besserer, U.; Blaum, K.; Bode, T.; Bornschein, B.; Bornschein, L.; Brunst, T.; Buzinsky, N.; Chilingaryan, S.; Choi, W. Q.; Deffert, M.; Doe, P. J.; Dragoun, O.; Drexlin, G.; Dyba, S.; Edzards, F.; Eitel, K.; Ellinger, E.; Engel, R.; Enomoto, S.; Erhard, M.; Eversheim, D.; Fedkevych, M.; Fischer, S.; Formaggio, J. A.; Fränkle, F. M.; Franklin, G. B.; Friedel, F.; Fulst, A.; Gil, W.; Glück, F.; Ureña, A. Gonzalez; Grohmann, S.; Grössle, R.; Gumbsheimer, R.; Hackenjos, M.; Hannen, V.; Harms, F.; Haußmann, N.; Heizmann, F.; Helbing, K.; Herz, W.; Hickford, S.; Hilk, D.; Hillesheimer, D.; Howe, M. A.; Huber, A.; Jansen, A.; Kellerer, J.; Kernert, N.; Kippenbrock, L.; Kleesiek, M.; Klein, M.; Kopmann, A.; Korzeczek, M.; Kovalík, A.; Krasch, B.; Kraus, M.; Kuckert, L.; Lasserre, T.; Lebeda, O.; Letnev, J.; Lokhov, A.; Machatschek, M.; Marsteller, A.; Martin, E. L.; Mertens, S.; Mirz, S.; Monreal, B.; Neumann, H.; Niemes, S.; Off, A.; Osipowicz, A.; Otten, E.; Parno, D. S.; Pollithy, A.; Poon, A. W. P.; Priester, F.; Ranitzsch, P. C.-O.; Rest, O.; Robertson, R. G. H.; Roccati, F.; Rodenbeck, C.; Röllig, M.; Röttele, C.; Ryšavý, M.; Sack, R.; Saenz, A.; Schimpf, L.; Schlösser, K.; Schlösser, M.; Schönung, K.; Schrank, M.; Seitz-Moskaliuk, H.; Sentkerestiová, J.; Sibille, V.; Slezák, M.; Steidl, M.; Steinbrink, N.; Sturm, M.; Suchopar, M.; Suesser, M.; Telle, H. H.; Thorne, L. A.; Thümmler, T.; Titov, N.; Tkachev, I.; Trost, N.; Valerius, K.; Vénos, D.; Vianden, R.; Hernández, A. P. Vizcaya; Weber, M.; Weinheimer, C.; Weiss, C.; Welte, S.; Wendel, J.; Wilkerson, J. F.; Wolf, J.; Wüstling, S.; Zadoroghny, S.

2018-05-01

The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at - 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two ^{83{m}}Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor M=1972.449(10) of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.

[Nutrient contents and microbial populations of aeolian sandy soil in Sanjiangyuan region of Qinghai Province].

PubMed

Lin, Chao-feng; Chen, Zhan-quan; Xue, Quan-hong; Lai, Hang-xian; Chen, Lai-sheng; Zhang, Deng-shan

2007-01-01

Sanjiangyuan region (the headstream of three rivers) in Qinghai Province of China is the highest and largest inland alpine wetland in the world. The study on the nutrient contents and microbial populations of aeolian sandy soils in this region showed that soil organic matter content increased with the evolution of aeolian sand dunes from un-stabilized to stabilized state, being 5.9 and 3.8 times higher in stabilized sand dune than in mobile and semi-stabilized sand dunes, respectively. Soil nitrogen and phosphorus contents increased in line with the amount of organic matter, while potassium content and pH value varied slightly. The microbial populations changed markedly with the development of vegetation, fixing of mobile sand, and increase of soil nutrients. The quantities of soil bacteria, fungi and actinomycetes were 4.0 and 2.8 times, 19.6 and 6.3 times, and 12.4 and 2.6 times higher in stabilized and semi-stabilized sand dunes than in mobile sand dune, respectively, indicating that soil microbial bio-diversity was increased with the evolution of aeolian sand dunes from mobile to stabilized state. In addition, the quantities of soil microbes were closely correlated with the contents of soil organic matter, total nitrogen, and available nitrogen and phosphorus, but not correlated with soil total phosphorus, total and available potassium, or pH value.

Influence of Femoral Component Design on Retrograde Femoral Nail Starting Point.

PubMed

Service, Benjamin C; Kang, William; Turnbull, Nathan; Langford, Joshua; Haidukewych, George; Koval, Kenneth J

2015-10-01

Our experience with retrograde femoral nailing after periprosthetic distal femur fractures was that femoral components with deep trochlear grooves posteriorly displace the nail entry point resulting in recurvatum deformity. This study evaluated the influence of distal femoral prosthetic design on the starting point. One hundred lateral knee images were examined. The distal edge of Blumensaat's line was used to create a ratio of its location compared with the maximum anteroposterior condylar width called the starting point ratio (SPR). Femoral trials from 6 manufacturers were analyzed to determine the location of simulated nail position in the sagittal plane compared with the maximum anteroposterior prosthetic width. These measurements were used to create a ratio, the femoral component ratio (FCR). The FCR was compared with the SPR to determine if a femoral component would be at risk for retrograde nail starting point posterior to the Blumensaat's line. The mean SPR was 0.392 ± 0.03, and the mean FCR was 0.416 ± 0.05, which was significantly greater (P = 0.003). The mean FCR was 0.444 ± 0.06 for the cruciate retaining (CR) trials and was 0.393 ± 0.04 for the posterior stabilized trials; this difference was significant (P < 0.001). The FCR for the femoral trials studied was significantly greater than the SPR for native knees and was significantly greater for CR femoral components compared with posterior stabilized components. These findings demonstrate that many total knee prostheses, particularly CR designs, are at risk for a starting point posterior to Blumensaat's line.

TP53-dependent chromosome instability is associated with transient reductions in telomere length in immortal telomerase-positive cell lines

NASA Technical Reports Server (NTRS)

Schwartz, J. L.; Jordan, R.; Liber, H.; Murnane, J. P.; Evans, H. H.

2001-01-01

Telomere shortening in telomerase-negative somatic cells leads to the activation of the TP53 protein and the elimination of potentially unstable cells. We examined the effect of TP53 gene expression on both telomere metabolism and chromosome stability in immortal, telomerase-positive cell lines. Telomere length, telomerase activity, and chromosome instability were measured in multiple clones isolated from three related human B-lymphoblast cell lines that vary in TP53 expression; TK6 cells express wild-type TP53, WTK1 cells overexpress a mutant form of TP53, and NH32 cells express no TP53 protein. Clonal variations in both telomere length and chromosome stability were observed, and shorter telomeres were associated with higher levels of chromosome instability. The shortest telomeres were found in WTK1- and NH32-derived cells, and these cells had 5- to 10-fold higher levels of chromosome instability. The primary marker of instability was the presence of dicentric chromosomes. Aneuploidy and other stable chromosome alterations were also found in clones showing high levels of dicentrics. Polyploidy was found only in WTK1-derived cells. Both telomere length and chromosome instability fluctuated in the different cell populations with time in culture, presumably as unstable cells and cells with short telomeres were eliminated from the growing population. Our results suggest that transient reductions in telomere lengths may be common in immortal cell lines and that these alterations in telomere metabolism can have a profound effect on chromosome stability. Copyright 2000 Wiley-Liss, Inc.

Evaluation of stabilization techniques for ion implant processing

NASA Astrophysics Data System (ADS)

Ross, Matthew F.; Wong, Selmer S.; Minter, Jason P.; Marlowe, Trey; Narcy, Mark E.; Livesay, William R.

1999-06-01

With the integration of high current ion implant processing into volume CMOS manufacturing, the need for photoresist stabilization to achieve a stable ion implant process is critical. This study compares electron beam stabilization, a non-thermal process, with more traditional thermal stabilization techniques such as hot plate baking and vacuum oven processing. The electron beam processing is carried out in a flood exposure system with no active heating of the wafer. These stabilization techniques are applied to typical ion implant processes that might be found in a CMOS production process flow. The stabilization processes are applied to a 1.1 micrometers thick PFI-38A i-line photoresist film prior to ion implant processing. Post stabilization CD variation is detailed with respect to wall slope and feature integrity. SEM photographs detail the effects of the stabilization technique on photoresist features. The thermal stability of the photoresist is shown for different levels of stabilization and post stabilization thermal cycling. Thermal flow stability of the photoresist is detailed via SEM photographs. A significant improvement in thermal stability is achieved with the electron beam process, such that photoresist features are stable to temperatures in excess of 200 degrees C. Ion implant processing parameters are evaluated and compared for the different stabilization methods. Ion implant system end-station chamber pressure is detailed as a function of ion implant process and stabilization condition. The ion implant process conditions are detailed for varying factors such as ion current, energy, and total dose. A reduction in the ion implant systems end-station chamber pressure is achieved with the electron beam stabilization process over the other techniques considered. This reduction in end-station chamber pressure is shown to provide a reduction in total process time for a given ion implant dose. Improvements in the ion implant process are detailed across several combinations of current and energy.

Aerodynamic Simulation Analysis of Unmanned Airborne Electronic Bomb

NASA Astrophysics Data System (ADS)

Yang, Jiaoying; Guo, Yachao

2017-10-01

For microelectronic bombs for UAVs, on the basis of the use of rotors to lift the insurance on the basis of ammunition, increased tail to increase stability. The aerodynamic simulation of the outer structure of the ammunition was carried out by FLUENT software. The resistance coefficient, the lift coefficient and the pitch moment coefficient under different angle of attack and Mach number were obtained, and the aerodynamic characteristics of the electronic bomb were studied. The pressure line diagram and the velocity line diagram of the flow around the bomb are further analyzed, and the rationality of the external structure is verified, which provides a reference for the subsequent design of the electronic bomb.

A comparative evaluation of dimensional stability of three types of interocclusal recording materials-an in-vitro multi-centre study.

PubMed

Tejo, Sampath Kumar; Kumar, Anil G; Kattimani, Vivekanand S; Desai, Priti D; Nalla, Sandeep; Chaitanya K, Krishna

2012-10-05

The introduction of different interocclusal recording materials has put clinicians in dilemma that which material should be used in routine clinical practice for precise recording and transferring of accurate existing occlusal records for articulation of patient's diagnostic or working casts in the fabrication of good satisfactory prosthesis. In the era of developing world of dentistry the different materials are introduced for interocclusal record with different brand names because of this; the utility of the material is confusing for successful delivery of prosthesis with lack of in vitro or in vivo studies which will predict the property of the material with utility recommendations. The aim of this multicenter research is to evaluate the time dependent linear dimensional stability of three types of interocclusal recording materials; which gives very clear idea to clinicians in regard to its usage in routine practice and recommendations for usage of the different materials. Also to find out ideal time for articulation of three types of interocclusal recording materials with accuracy. Commercially available and ADA approved Polyether bite registration paste (Ramitec), Poly vinyl siloxane bite registration paste (Jetbite) and Zinc oxide eugenol (ZOE) bite registration paste (Super bite) were used in the study.A stainless steel die was made according to modified American dental Associations (ADA) specification no. 19. Each one of the tested materials were manipulated according to manufacturers' instructions. The materials separated from die, 3-mins after their respective setting time, resulted in disks of standard diameter. Two parallel lines and three perpendicular lines reproduced on the surface. The distance between two parallel lines was measured at different time intervals i.e. 1 hour, 24, 48 and 72 hours by using travelling microscope (magnus) and compared with standard die measurements made according to ADA specification no.19 to find out the dimensional stability of these interocclusal recording materials. Total 120 samples were made for observation and results were subjected to statistical analysis. Statistical analysis was performed using analysis of variance (ANOVA) and then Tukey's Honestly Significant Difference (HSD) test for comparison among groups at the 0.05 level of significance. After statistical analysis of the data, results were obtained and analyzed for interpretation. The results shows significant difference between the dimensional stability of all three material at different intervals with p-value <0.05. Comparatively the polyether bite registration material showed less distortion with good dimensional stability compared to Poly vinyl siloxane bite (Jetbite), Zinc oxide eugenol(ZOE) bite (Super bite) at 1 hour, 24, 48, and 72 hours. The dimensional stability decreased with increase in time and is influenced by both material factor and time factor. Polyether was found to be more dimensionally stable interocclusal recording material, which was followed by Silicone and Zinc oxide eugenol (ZOE). The dimensional stability of Polyether was good. Zinc oxide eugenol is dimensionally more unstable when compared with polyether and polyvinyl siloxane. We recommend that the polyether interocclusal records must be articulated within 48 hours and Polyvinylsiloxane interocclusal records must be articulated within 24 hours and the ZOE should be articulated within 1 hour to get a correct restoration to have very minimum distortion and maximum satisfaction without failure of prosthesis.

Borderline Personality Disorder: Bipolarity, Mood Stabilizers and Atypical Antipsychotics in Treatment

PubMed Central

Belli, Hasan; Ural, Cenk; Akbudak, Mahir

2012-01-01

In this article, it is aimed to review the efficacies of mood stabilizers and atypical antipsychotics, which are used commonly in psychopharmacological treatments of bipolar and borderline personality disorders. In this context, common phenomenology between borderline personality and bipolar disorders and differential features of clinical diagnosis will be reviewed in line with the literature. Both disorders can demonstrate common features in the diagnostic aspect, and can overlap phenomenologically. Concomitance rate of both disorders is quite high. In order to differentiate these two disorders from each other, quality of mood fluctuations, impulsivity types and linear progression of disorders should be carefully considered. There are various studies in mood stabilizer use, like lithium, carbamazepine, oxcarbazepine, sodium valproate and lamotrigine, in the treatment of borderline personality disorder. Moreover, there are also studies, which have revealed efficacies of risperidone, olanzapine and quetiapine as atypical antipsychotics. It is not easy to differentiate borderline personality disorder from the bipolar disorders. An intensively careful evaluation should be performed. This differentiation may be helpful also for the treatment. There are many studies about efficacy of valproate and lamotrigine in treatment of borderline personality disorder. However, findings related to other mood stabilizers are inadequate. Olanzapine and quetiapine are reported to be more effective among atypical antipsychotics. No drug is approved for the treatment of borderline personality disorder by the entitled authorities, yet. Psychotherapeutic approaches have preserved their significant places in treatment of borderline personality disorder. Moreover, symptom based approach is recommended in use of mood stabilizers and atypical antipsychotics. PMID:23024731

Spectrophone stabilized laser with line center offset frequency control

NASA Technical Reports Server (NTRS)

Kavaya, M. J.; Menzies, R. T. (Inventor)

1984-01-01

Continuous offset tuning of a frequency stabilized CW gas laser is achieved by using a spectrophone filled with the same gas as the laser for sensing a dither modulation, detecting a first or second derivative of the spectrophone output with a lock-in amplifier, the detected output of which is integrated, and applying the integrator output as a correction signal through a circuit which adds to the dither signal from an oscillator a dc offset that is adjusted with a potentiometer to a frequency offset from the absorption line center of the gas, but within the spectral linewidth of the gas. Tuning about that offset frequency is achieved by adding a dc value to the detected output of the dither modulation before integration using a potentiometer.

A high-performance Hg(+) trapped ion frequency standard

NASA Technical Reports Server (NTRS)

Prestage, J. D.; Tjoelker, R. L.; Dick, G. J.; Maleki, L.

1992-01-01

A high-performance frequency standard based on (199)Hg(+) ions confined in a hybrid radio frequency (RF)/dc linear ion trap is demonstrated. This trap permits storage of large numbers of ions with reduced susceptibility to the second-order Doppler effect caused by the RF confining fields. A 160-mHz-wide atomic resonance line for the 40.5-GHz clock transition is used to steer the output of a 5-mHz crystal oscillator to obtain a stability of 2 x 10(exp -15) for 24,000-second averaging times. Measurements with a 37-mHz line width for the Hg(+) clock transition demonstrate that the inherent stability for this frequency standard is better than 1 x 10(exp -15) at 10,000-second averaging times.

Effect of Storage Time and Temperature on Dimensional Stability of Impressions Made with Zinc Oxide Impression Paste

PubMed Central

Habibzadeh, Sareh; Safaeian, Shima; Behruzibakhsh, Marjan; Kaviyani, Parisa; Kharazifard, Mohamadjavad

2016-01-01

Objectives: This study aimed to assess the effect of storage time and temperature on dimensional stability of impressions made with Cavex Outline zinc oxide impression paste. Materials and Methods: A round stainless steel mold with five grooves (three horizontal and two vertical) was used in this in-vitro experimental study. Cavex Outline impression paste was prepared according to the manufacturer’s instructions and applied to the mold. The mold was placed on a block and stored at 35°C and 100% humidity for setting. The impressions were poured with stone immediately and also after 30, 120, 240 and 420 minutes and 24 hours. The distance between the vertical lines on the casts was measured and compared with that in the immediately poured cast. Results: Storage in a refrigerator and at room temperature for zero to seven hours had no significant effect on dimensional stability of the impressions; however, 24 hours of storage in a refrigerator or at room temperature decreased the dimensional stability of Cavex Outline (P=0.001). Also, a significant association was found between dimensional changes following 24 hours of storage in a refrigerator (4°C) and at room temperature (23°C; P<0.01). Conclusions: The optimal pouring time of Cavex Outline impressions with stone is between zero to seven hours, and 24 hours of storage significantly decreases the dimensional stability. PMID:28392816

Effects of nuclear electromagnetic pulse (EMP) on synchronous stability of the electric power system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manweiler, R.W.

1975-11-01

The effects of a nuclear electromagnetic pulse (EMP) on the synchronous stability of the electric power transmission and distribution systems are evaluated. The various modes of coupling of EMP to the power system are briefly discussed, with particular emphasis on those perturbations affecting the synchronous stability of the transmission system. A brief review of the fundamental concepts of the stability problem is given, with a discussion of the general characteristics of transient analysis. A model is developed to represent single sets as well as repetitive sets of multiple faults on the distribution systems, as might be produced by EMP. Themore » results of many numerical stability calculations are presented to illustrate the transmission system's response from different types of perturbations. The important parameters of both multiple and repetitive faults are studied, including the dependence of the response on the size of the perturbed area, the fault density, and the effective impedance between the fault location and the transmission system. Both major load reduction and the effect of the opening of tie lines at the time of perturbation are also studied. We conclude that there is a high probability that EMP can induce perturbations on the distribution networks causing a large portion of the transmission network in the perturbed area to lose synchronism. The result would be an immediate and massive power failure. (auth)« less

Stabilization and disposal of Argonne-West low-level mixed wastes in ceramicrete waste forms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barber, D. B.; Singh, D.; Strain, R. V.

1998-02-17

The technology of room-temperature-setting phosphate ceramics or Ceramicrete{trademark} technology, developed at Argonne National Laboratory (ANL)-East is being used to treat and dispose of low-level mixed wastes through the Department of Energy complex. During the past year, Ceramicrete{trademark} technology was implemented for field application at ANL-West. Debris wastes were treated and stabilized: (a) Hg-contaminated low-level radioactive crushed light bulbs and (b) low-level radioactive Pb-lined gloves (part of the MWIR {number_sign} AW-W002 waste stream). In addition to hazardous metals, these wastes are contaminated with low-level fission products. Initially, bench-scale waste forms with simulated and actual waste streams were fabricated by acid-base reactionsmore » between mixtures of magnesium oxide powders and an acid phosphate solution, and the wastes. Size reduction of Pb-lined plastic glove waste was accomplished by cryofractionation. The Ceramicrete{trademark} process produces dense, hard ceramic waste forms. Toxicity Characteristic Leaching Procedure (TCLP) results showed excellent stabilization of both Hg and Pb in the waste forms. The principal advantage of this technology is that immobilization of contaminants is the result of both chemical stabilization and subsequent microencapsulation of the reaction products. Based on bench-scale studies, Ceramicrete{trademark} technology has been implemented in the fabrication of 5-gal waste forms at ANL-West. Approximately 35 kg of real waste has been treated. The TCLP is being conducted on the samples from the 5-gal waste forms. It is expected that because the waste forms pass the limits set by the EPAs Universal Treatment Standard, they will be sent to a radioactive-waste disposal facility.« less

COED Transactions, Vol. IX, No. 1, January 1977. Rapid Production of System Phase-Plane Portraits on the EAI 380 Hybrid/Analog Computer.

ERIC Educational Resources Information Center

Marcovitz, Alan B., Ed.

The method of phase-plane presentation as an educational tool in the study of the dynamic behavior of systems is discussed. In the treatment of nonlinear or piecewise-linear systems, the phase-plane portrait is used to exhibit the nature of singular points, regions of stability, and switching lines to aid comprehension. A technique is described by…

Shotcrete for Expedient Structural Repair

DTIC Science & Technology

1991-12-01

pp. 29-44. Selmer - Olsen , R., "Examples of the Behavior of Shotcrete Linings Underground," Proceedings, Shotcrete for Ground Support, The Engineering... Selmer - Olsen , R. PAPER TITLE: Examples of the Behavior of Shotcrete Linings Underground DESCRIPTIVE TITLE NOTE: -0- BOOK/REPORT TITLE: Proceedings...prestressed tanks, thin overlays over structural materials, repair of concrete deteriorated by fire or earthquake, rock slope stabilization, and

Identifying energy and carbon footprint optimization potentials of a sludge treatment line with Life Cycle Assessment.

PubMed

Remy, C; Lesjean, B; Waschnewski, J

2013-01-01

This study exemplifies the use of Life Cycle Assessment (LCA) as a tool to quantify the environmental impacts of processes for wastewater treatment. In a case study, the sludge treatment line of a large wastewater treatment plant (WWTP) is analysed in terms of cumulative energy demand and the emission of greenhouse gases (carbon footprint). Sludge treatment consists of anaerobic digestion, dewatering, drying, and disposal of stabilized sludge in mono- or co-incineration in power plants or cement kilns. All relevant forms of energy demand (electricity, heat, chemicals, fossil fuels, transport) and greenhouse gas emissions (fossil CO(2), CH(4), N(2)O) are accounted in the assessment, including the treatment of return liquor from dewatering in the WWTP. Results show that the existing process is positive in energy balance (-162 MJ/PE(COD) * a) and carbon footprint (-11.6 kg CO(2)-eq/PE(COD) * a) by supplying secondary products such as electricity from biogas production or mono-incineration and substituting fossil fuels in co-incineration. However, disposal routes for stabilized sludge differ considerably in their energy and greenhouse gas profiles. In total, LCA proves to be a suitable tool to support future investment decisions with information of environmental relevance on the impact of wastewater treatment, but also urban water systems in general.

Amorphous silicon photovoltaic manufacturing technology, phase 2A

NASA Astrophysics Data System (ADS)

Duran, G.; Mackamul, K.; Metcalf, D.

1995-01-01

Utility Power Group (UPG), and its lower-tier subcontractor, Advanced Photovoltaic Systems, Inc. (APS) have conducted efforts in developing their manufacturing lines. UPG has focused on the automation of encapsulation and termination processes developed in Phase 1. APS has focused on completion of the encapsulation and module design tasks, while continuing the process and quality control and automation projects. The goal is to produce 55 watt (stabilized) EP50 modules in a new facility. In the APS Trenton EUREKA manufacturing facility, APS has: (1) Developed high throughput lamination procedures; (2) Optimized existing module designs; (3) Developed new module designs for architectural applications; (4) Developed enhanced deposition parameter control; (5) Designed equipment required to manufacture new EUREKA modules developed during Phase II; (6) Improved uniformity of thin-film materials deposition; and (7) Improved the stabilized power output of the APS EP50 EUREKA module to 55 watts. In the APS Fairfield EUREKA manufacturing facility, APS has: (1) Introduced the new products developed under Phase 1 into the APS Fairfield EUREKA module production line; (2) Increased the extent of automation in the production line; (3) Introduced Statistical Process Control to the module production line; and (4) Transferred-progress made in the APS Trenton facility into the APS Fairfield facility.

Line-of-sight pointing accuracy/stability analysis and computer simulation for small spacecraft

NASA Astrophysics Data System (ADS)

Algrain, Marcelo C.; Powers, Richard M.

1996-06-01

This paper presents a case study where a comprehensive computer simulation is developed to determine the driving factors contributing to spacecraft pointing accuracy and stability. The simulation is implemented using XMATH/SystemBuild software from Integrated Systems, Inc. The paper is written in a tutorial manner and models for major system components are described. Among them are spacecraft bus, attitude controller, reaction wheel assembly, star-tracker unit, inertial reference unit, and gyro drift estimators (Kalman filter). THe predicted spacecraft performance is analyzed for a variety of input commands and system disturbances. The primary deterministic inputs are desired attitude angles and rate setpoints. The stochastic inputs include random torque disturbances acting on the spacecraft, random gyro bias noise, gyro random walk, and star-tracker noise. These inputs are varied over a wide range to determine their effects on pointing accuracy and stability. The results are presented in the form of trade-off curves designed to facilitate the proper selection of subsystems so that overall spacecraft pointing accuracy and stability requirements are met.

Topological transport in Dirac nodal-line semimetals

NASA Astrophysics Data System (ADS)

Rui, W. B.; Zhao, Y. X.; Schnyder, Andreas P.

2018-04-01

Topological nodal-line semimetals are characterized by one-dimensional Dirac nodal rings that are protected by the combined symmetry of inversion P and time-reversal T . The stability of these Dirac rings is guaranteed by a quantized ±π Berry phase and their low-energy physics is described by a one-parameter family of (2+1)-dimensional quantum field theories exhibiting the parity anomaly. Here we study the Berry-phase supported topological transport of P T -invariant nodal-line semimetals. We find that small inversion breaking allows for an electric-field-induced anomalous transverse current, whose universal component originates from the parity anomaly. Due to this Hall-like current, carriers at opposite sides of the Dirac nodal ring flow to opposite surfaces when an electric field is applied. To detect the topological currents, we propose a dumbbell device, which uses surface states to filter charges based on their momenta. Suggestions for experiments and device applications are discussed.

Quasi-static and dynamic magnetic tension forces in arched, line-tied magnetic flux ropes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, C. E.; Yamada, M.; Ji, H.

Solar eruptions are often driven by magnetohydrodynamic instabilities such as the torus and kink instabilities that act on line-tied magnetic flux ropes. We designed our recent laboratory experiments to study these eruptive instabilities which have demonstrated the key role of both dynamic (Myers et al 2015 Nature 528 526) and quasi-static (Myers et al 2016 Phys. Plasmas 23 112102) magnetic tension forces in contributing to the equilibrium and stability of line-tied magnetic flux ropes. In our paper, we synthesize these laboratory results and explore the relationship between the dynamic and quasi-static tension forces. And while the quasi-static tension force ismore » found to contribute to the flux rope equilibrium in a number of regimes, the dynamic tension force is substantial mostly in the so-called failed torus regime where magnetic self-organization events prevent the flux rope from erupting.« less

Quasi-static and dynamic magnetic tension forces in arched, line-tied magnetic flux ropes

DOE PAGES

Myers, C. E.; Yamada, M.; Ji, H.; ...

2016-11-22

Solar eruptions are often driven by magnetohydrodynamic instabilities such as the torus and kink instabilities that act on line-tied magnetic flux ropes. We designed our recent laboratory experiments to study these eruptive instabilities which have demonstrated the key role of both dynamic (Myers et al 2015 Nature 528 526) and quasi-static (Myers et al 2016 Phys. Plasmas 23 112102) magnetic tension forces in contributing to the equilibrium and stability of line-tied magnetic flux ropes. In our paper, we synthesize these laboratory results and explore the relationship between the dynamic and quasi-static tension forces. And while the quasi-static tension force ismore » found to contribute to the flux rope equilibrium in a number of regimes, the dynamic tension force is substantial mostly in the so-called failed torus regime where magnetic self-organization events prevent the flux rope from erupting.« less

Frequency-comb-assisted precision laser spectroscopy of CHF{sub 3} around 8.6 μm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gambetta, Alessio; Coluccelli, Nicola; Cassinerio, Marco

2015-12-21

We report a high-precision spectroscopic study of room-temperature trifluoromethane around 8.6 μm, using a CW quantum cascade laser phase-locked to a mid-infrared optical frequency comb. This latter is generated by a nonlinear down-conversion process starting from a dual-branch Er:fiber laser and is stabilized against a GPS-disciplined rubidium clock. By tuning the comb repetition frequency, several transitions falling in the υ{sub 5} vibrational band are recorded with a frequency resolution of 20 kHz. Due to the very dense spectra, a special multiple-line fitting code, involving a Voigt profile, is developed for data analysis. The combination of the adopted experimental approach andmore » survey procedure leads to fractional accuracy levels in the determination of line center frequencies, down to 2 × 10{sup −10}. Line intensity factors, pressure broadening, and shifting parameters are also provided.« less

The sensory basis of rheotaxis in turbulent flow

NASA Astrophysics Data System (ADS)

Elder, John P.

Rheotaxis is a robust, multisensory behavior with many potential benefits for fish and other aquatic animals, yet the influence of different fluvial conditions on rheotactic performance and its sensory basis is still poorly understood. Here, we examine the role that vision and the lateral line play in the rheotactic behavior of a stream-dwelling species (Mexican tetra, Astyanax mexicanus) under both rectilinear and turbulent flow conditions. Turbulence enhanced overall rheotactic strength and lowered the flow speed at which rheotaxis was initiated; this effect did not depend on the availability of either visual or lateral line information. Compared to fish without access to visual information, fish with access to visual information exhibited increased levels of positional stability and as a result, increased levels of rheotactic accuracy. No disruption in rheotactic performance was found when the lateral line was disabled, suggesting that this sensory system is not necessary for either rheotaxis or turbulence detection under the conditions of this study.

Quantifying Stability in Complex Networks: From Linear to Basin Stability

NASA Astrophysics Data System (ADS)

Kurths, Jürgen

The human brain, power grids, arrays of coupled lasers and the Amazon rainforest are all characterized by multistability. The likelihood that these systems will remain in the most desirable of their many stable states depends on their stability against significant perturbations, particularly in a state space populated by undesirable states. Here we claim that the traditional linearization-based approach to stability is in several cases too local to adequately assess how stable a state is. Instead, we quantify it in terms of basin stability, a new measure related to the volume of the basin of attraction. Basin stability is non-local, nonlinear and easily applicable, even to high-dimensional systems. It provides a long-sought-after explanation for the surprisingly regular topologies of neural networks and power grids, which have eluded theoretical description based solely on linear stability. Specifically, we employ a component-wise version of basin stability, a nonlinear inspection scheme, to investigate how a grid's degree of stability is influenced by certain patterns in the wiring topology. Various statistics from our ensemble simulations all support one main finding: The widespread and cheapest of all connection schemes, namely dead ends and dead trees, strongly diminish stability. For the Northern European power system we demonstrate that the inverse is also true: `Healing' dead ends by addition of transmission lines substantially enhances stability. This indicates a crucial smart-design principle for tomorrow's sustainable power grids: add just a few more lines to avoid dead ends. Further, we analyse the particular function of certain network motifs to promote the stability of the system. Here we uncover the impact of so-called detour motifs on the appearance of nodes with a poor stability score and discuss the implications for power grid design. Moreover, it will be shown that basin stability enables uncovering the mechanism for explosive synchronization and understanding of evolving networks. Reference: P. Menck, J. Heitzig, N. Marwan, and J. Kurths, Nature Physics 9, 89 (2013) P. Menck, J. Heitzig, J. Kurths, and H. Schellnhuber, Nature Communication 5, 3969 (2014) P. Schultz, J. Heitzig, and J. Kurths, New Journal Physics 16, 125001 (2014) V. Kohar, P. Ji, A. Choudhary, S. Sinha, and J. Kurths, Phys. Rev. E 90, 022812 (2014) Y. Zou, T. Pereira, M. Small, Z. Liu, and J. Kurths, Phys. Rev. Lett. 112, 114102 (2014)

78 FR 56612 - Seagoing Barges

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-13

..., measured parallel to the centerline. \\2\\ Subchapters E (Load Lines), F (Marine Engineering), J (Electrical Engineering), N (Dangerous Cargoes), S (Subdivision and Stability), and W (Lifesaving Appliances and...

Cell reintegration: Stray epithelial cells make their way home.

PubMed

Wilson, Tyler J; Bergstralh, Dan T

2017-06-01

Ongoing work shows that misplaced epithelial cells have the capacity to reintegrate back into tissue layers. This movement appears to underlie tissue stability and may also control aspects of tissue structure. A recent study reveals that cell reintegration in at least one tissue, the Drosophila follicular epithelium, is based on adhesion molecules that line lateral cell surfaces. In this article we will review these observations, discuss their implications for epithelial tissue development and maintenance, and identify future directions for study. © 2017 WILEY Periodicals, Inc.

Stability analysis of BWR nuclear-coupled thermal-hyraulics using a simple model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karve, A.A.; Rizwan-uddin; Dorning, J.J.

1995-09-01

A simple mathematical model is developed to describe the dynamics of the nuclear-coupled thermal-hydraulics in a boiling water reactor (BWR) core. The model, which incorporates the essential features of neutron kinetics, and single-phase and two-phase thermal-hydraulics, leads to simple dynamical system comprised of a set of nonlinear ordinary differential equations (ODEs). The stability boundary is determined and plotted in the inlet-subcooling-number (enthalpy)/external-reactivity operating parameter plane. The eigenvalues of the Jacobian matrix of the dynamical system also are calculated at various steady-states (fixed points); the results are consistent with those of the direct stability analysis and indicate that a Hopf bifurcationmore » occurs as the stability boundary in the operating parameter plane is crossed. Numerical simulations of the time-dependent, nonlinear ODEs are carried out for selected points in the operating parameter plane to obtain the actual damped and growing oscillations in the neutron number density, the channel inlet flow velocity, and the other phase variables. These indicate that the Hopf bifurcation is subcritical, hence, density wave oscillations with growing amplitude could result from a finite perturbation of the system even where the steady-state is stable. The power-flow map, frequently used by reactor operators during start-up and shut-down operation of a BWR, is mapped to the inlet-subcooling-number/neutron-density (operating-parameter/phase-variable) plane, and then related to the stability boundaries for different fixed inlet velocities corresponding to selected points on the flow-control line. The stability boundaries for different fixed inlet subcooling numbers corresponding to those selected points, are plotted in the neutron-density/inlet-velocity phase variable plane and then the points on the flow-control line are related to their respective stability boundaries in this plane.« less

A Comparative Study of Discovery Learning Scientific Community Laboratories and Traditional Laboratories in Physics at an Independent University, Florida, U. S

NASA Astrophysics Data System (ADS)

Reinhard, Karl E.

Electric power is fully interwoven into the fabric of American life. Its loss for extended periods has profound impacts upon public safety, health and welfare. The power system has been termed the most complex machine built by man. Not surprisingly, the measures to address the range of power system downtime causes are as diverse as the causes themselves. One important arc of effort is providing power system operators with full knowledge of the system's operating state, timely warning when changing conditions threaten system stability, and tools guiding control actions to maintain stable operations. This research is motivated, in part, by the need to explore opportunities for leveraging nascent synchrophasor data streams against known power system stability challenges. Over the past half-decade, power system operators have aggressively installed large networks of phasor measurement units (PMUs) and phasor data concentrators (PDCs) across the United States and Canada. Today, the synchrophasor data network has reached a state of maturity that opens the door to useful application. This dissertation investigates power system stability along three lines of effort. The first two efforts address steady-state power system stability--specifically methods for assessing system vulnerabilities arising from the phase angle difference between two buses connected by a transmission line. The third effort investigates the information that can be gleaned from synchrophasor measurements during a system's dynamic system response to changing system conditions. The first line of investigation extends steady-state distribution factor theory. Distribution factors are computed from a known non-linear power system load flow solution. They provide a computationally light method for estimating new system conditions under different operating circumstances. Distribution factors are extremely useful for very rapidly screening the impact of unexpected changes in power system configuration--e.g. a transmission line dropping out of service due to environmental conditions. The Line Outage Angle Factor (LOAF) developed herein provides a method for fast computation of bus voltage angle changes after a line outage. The Line Outage Generator Factor (LOGF) modifies the simulated circuit topology to include synchronous machine transient reactances, enabling rapid screening of operating states in which line opening (or re-closure) risks damaging equipment. The LOAF and LOGF provide promising results in MATLAB simulation of the Western System Coordinating Council 3-Machine, 9-Bus System. The second investigative line seeks to develop a Thevenin equivalent model to be used in tandem with synchrophasor data streams to provide real-time bus angle difference information for buses connected by a transmission line. The appeal is that real-time bus angle difference information could be computed on-site and very rapidly--and significantly, independent of other network bus measurements. The results show that developing a Thevenin equivalent that provides a useful angle difference measure often works well on paper, but is challenging using actual synchrophasor data. Efforts to develop a Thevenin equivalent using Monte Carlo methods show promise, but require further investigation. The third line of effort shifts to investigate the useful information that a PMU can produce during a power system disturbance event. A synchrophasor is defined at a specific frequency, i.e. the system steady-state operating frequency. Thus a PMU produces a data stream recording power system changes progressing slower than the nominal system frequency; consequently, this is an "off-label" synchrophasor data application. The test system is a generator with electrical and mechanical controls connected by a pair of identical transmission lines to an infinite bus. The synchronous generator is modeled as a three-damper-winding synchronous machine. A MATLAB simulation was written to simulate both the full 14 dynamic state and the reduced order 11 dynamic state system models. A Real-Time Digital Simulator (RTDS) simulation emulating the test system provides the capability to produce real-time analog generator terminal waveforms to be sampled by a commercial off-the-shelf PMU to produce synchrophasor data. We find that the RTDS generated synchrophasor data stream is similar to the MATLAB reduced order model voltage and current generator terminal data in the dqo reference frame--reflecting parallel, but distinct, filtering processes.

Bionic Vision-Based Intelligent Power Line Inspection System

PubMed Central

Ma, Yunpeng; He, Feijia; Xu, Jinxin

2017-01-01

Detecting the threats of the external obstacles to the power lines can ensure the stability of the power system. Inspired by the attention mechanism and binocular vision of human visual system, an intelligent power line inspection system is presented in this paper. Human visual attention mechanism in this intelligent inspection system is used to detect and track power lines in image sequences according to the shape information of power lines, and the binocular visual model is used to calculate the 3D coordinate information of obstacles and power lines. In order to improve the real time and accuracy of the system, we propose a new matching strategy based on the traditional SURF algorithm. The experimental results show that the system is able to accurately locate the position of the obstacles around power lines automatically, and the designed power line inspection system is effective in complex backgrounds, and there are no missing detection instances under different conditions. PMID:28203269

[Enhanced resistance to emotional stress through the use of D-phenylalanine].

PubMed

Iumatov, E A; Sarychev, E I; Kozlovskiĭ, I I; Mineeva, M F; Demidov, V M; Morozov, I S; Kozlovskaia, M M

1991-01-01

Stress-protective action was studied of D-phenylalanine, having an ability to decrease destruction of endogenic enkefalins. In the experiments stability of the experimental (receiving D-phenylalanine) and control groups of male rats of August line to emotional stress was compared in conditions of immobilization stress by parameters of animals survival rate, adrenal glands hypertrophy development, involution of thymus, pathologic changes in lungs (abscesses development), ulcero-dystrophic disturbances in stomach, and also the activity and kinetic properties of enzyme tyrosin-hydroxylase in the hypothalamus were determined. It was shown that by several of the mentioned physiological parameters the D-phenylalanine significantly increased the animals stability to the emotional stress and decreased tyrosinhydroxylase activity which participates in activation of katecholaminergic processes.

Photometric Repeatability of Scanned Imagery: UVIS

NASA Astrophysics Data System (ADS)

Shanahan, Clare E.; McCullough, Peter; Baggett, Sylvia

2017-08-01

We provide the preliminary results of a study on the photometric repeatability of spatial scans of bright, isolated white dwarf stars with the UVIS channel of the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). We analyze straight-line scans from the first pair of identical orbits of HST program 14878 to assess if sub 0.1% repeatability can be attained with WFC3/UVIS. This study is motivated by the desire to achieve better signal-to-noise in the UVIS contamination and stability monitor, in which observations of standard stars in staring mode have been taken from the installation of WFC3 in 2009 to the present to assess temporal photometric stability. Higher signal to noise in this program would greatly benefit the sensitivity to detect contamination, and to better characterize the observed small throughput drifts over time. We find excellent repeatability between identical visits of program 14878, with sub 0.1% repeatability achieved in most filters. These! results support the initiative to transition the staring mode UVIS contamination and photometric stability monitor from staring mode images to spatial scans.

Power flow control using quadrature boosters

NASA Astrophysics Data System (ADS)

Sadanandan, Sandeep N.

A power system that can be controlled within security constraints would be an advantage to power planners and real-time operators. Controlling flows can lessen reliability issues such as thermal limit violations, power stability problems, and/or voltage stability conditions. Control of flows can also mitigate market issues by reducing congestion on some lines and rerouting power to less loaded lines or onto preferable paths. In the traditional control of power flows, phase shifters are often used. More advanced methods include using Flexible AC Transmission System (FACTS) Controllers. Some examples include Thyristor Controlled Series Capacitors, Synchronous Series Static Compensators, and Unified Power Flow Controllers. Quadrature Boosters (QBs) have similar structures to phase-shifters, but allow for higher voltage magnitude during real power flow control. In comparison with other FACTS controllers QBs are not as complex and not as expensive. The present study proposes to use QBs to control power flows on a power system. With the inclusion of QBs, real power flows can be controlled to desired scheduled values. In this thesis, the linearized power flow equations used for power flow analysis were modified for the control problem. This included modifying the Jacobian matrix, the power error vector, and calculating the voltage injected by the quadrature booster for the scheduled real power flow. Two scenarios were examined using the proposed power flow control method. First, the power flow in a line in a 5-bus system was modified with a QB using the method developed in this thesis. Simulation was carried out using Matlab. Second, the method was applied to a 30-bus system and then to a 118-bus system using several QBs. In all the cases, the calculated values of the QB voltages led to desired power flows in the designated line.

Surface Nanobubbles Are Stabilized by Hydrophobic Attraction.

PubMed

Tan, Beng Hau; An, Hongjie; Ohl, Claus-Dieter

2018-04-20

The remarkably long lifetime of surface nanobubbles has perplexed researchers for two decades. The current understanding is that both contact line pinning and supersaturation of the ambient liquid are strictly required for the stability of nanobubbles, yet experiments show nanobubbles surviving in open systems and undersaturated environments. We find that this discrepancy can be addressed if the effects of an attractive hydrophobic potential at the solid substrate on the spatial distribution of the gas concentration is taken into account. We also show that, in our model, only substrate pinning is strictly required for stabilization; while hydrophobicity and supersaturation both aid stability, neither is mandatory-the absence of one can be compensated by an excess of the other.

Surface Nanobubbles Are Stabilized by Hydrophobic Attraction

NASA Astrophysics Data System (ADS)

Tan, Beng Hau; An, Hongjie; Ohl, Claus-Dieter

2018-04-01

The remarkably long lifetime of surface nanobubbles has perplexed researchers for two decades. The current understanding is that both contact line pinning and supersaturation of the ambient liquid are strictly required for the stability of nanobubbles, yet experiments show nanobubbles surviving in open systems and undersaturated environments. We find that this discrepancy can be addressed if the effects of an attractive hydrophobic potential at the solid substrate on the spatial distribution of the gas concentration is taken into account. We also show that, in our model, only substrate pinning is strictly required for stabilization; while hydrophobicity and supersaturation both aid stability, neither is mandatory—the absence of one can be compensated by an excess of the other.

Parachute dynamics and stability analysis. [using nonlinear differential equations of motion

NASA Technical Reports Server (NTRS)

Ibrahim, S. K.; Engdahl, R. A.

1974-01-01

The nonlinear differential equations of motion for a general parachute-riser-payload system are developed. The resulting math model is then applied for analyzing the descent dynamics and stability characteristics of both the drogue stabilization phase and the main descent phase of the space shuttle solid rocket booster (SRB) recovery system. The formulation of the problem is characterized by a minimum number of simplifying assumptions and full application of state-of-the-art parachute technology. The parachute suspension lines and the parachute risers can be modeled as elastic elements, and the whole system may be subjected to specified wind and gust profiles in order to assess their effects on the stability of the recovery system.

Numerical study of blow-up and stability of line solitons for the Novikov-Veselov equation

NASA Astrophysics Data System (ADS)

Kazeykina, Anna; Klein, Christian

2017-07-01

We study numerically the evolution of perturbed Korteweg-de Vries solitons and of well localized initial data by the Novikov-Veselov (NV) equation at different levels of the ‘energy’ parameter E. We show that as \\vert E\\vert \\to ∞ , NV behaves, as expected, similarly to its formal limit, the Kadomtsev-Petviashvili equation. However at intermediate regimes, i.e. when \\vert E \\vert is not very large, more varied scenarios are possible, in particular, blow-ups are observed. The mechanism of the blow-up is studied.

ASK1 regulates the survival of neuroblastoma cells by interacting with TLX and stabilizing HIF-1α.

PubMed

Sobhan, Praveen K; Zhai, Qiwei; Green, Lydia C; Hansford, Loen M; Funa, Keiko

2017-01-01

Elevated expression of TLX (also called as NR2E1) in neuroblastoma (NB) correlates with unfavorable prognosis, and TLX is required for self-renewal of NB cells. Knockdown of TLX has been shown to reduce the NB sphere-forming ability. ASK1 (MAP3K5) and TLX expression are both enhanced in SP (side population) NB and patient-derived primary NB sphere cell lines, but the majority of non-SP NB lines express lower ASK1 expression. We found that ASK1 phosphorylated and stabilized TLX, which led induction of HIF-1α, and its downstream VEGF-A in an Akt dependent manner. In depleting ASK1 upon hypoxia, TLX decreased and the apoptosis ratio of NB cells was enhanced, while low-ASK1-expressing NB cell lines were refractory in TUNEL assay by using flow cytometry. Interestingly, primary NB spheres cell lines express only high levels of active pASK1Thr-838 but the established cell lines expressed inhibitory pASK1Ser-966, and both could be targeted by ASK1 depletion. We report a novel pro-survival role of ASK1 in the tumorigenic NB cell populations, which may be applied as a therapeutic target, inducing apoptosis specifically in cancer stem cells. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Looking Into and Through the Ross Ice Shelf - ROSETTA-ICE

NASA Astrophysics Data System (ADS)

Bell, R. E.

2015-12-01

Our current understanding of the structure and stability of the Ross Ice Shelf is based on satellite studies of the ice surface and the 1970's RIGGS program. The study of the flowlines evident in the MODIS imagery combined with surface geophysics has revealed a complex history with ice streams Mercer, Whillans and Kamb changing velocity over the past 1000 years. Here, we present preliminary IcePod and IceBridge radar data acquired in December 2014 and November 2013 across the Ross Ice Shelf that show clearly, for the first time, the structure of the ice shelf and provide insights into ice-ocean interaction. The three major layers of the ice shelf are (1) the continental meteoric ice layer), ice formed on the grounded ice sheet that entered the ice shelf where ice streams and outlet glaciers crossed the grounding line (2) the locally accumulating meteoric ice layer, ice and snow that forms from snowfall on the floating ice shelf and (3) a basal marine ice layer. The locally accumulating meteoric ice layer contains well-defined internal layers that are generally parallel to the ice surface and thickens away from the grounding line and reaches a maximum thickness of 220m along the line crossing Roosevelt Island. The continental meteoric layer is located below a broad irregular internal reflector, and is characterized by irregular internal layers. These internal layers are often folded, likely a result of deformation as the ice flowed across the grounding line. The basal marine ice layer, up to 50m thick, is best resolved in locations where basal crevasses are present, and appears to thicken along the flow at rates of decimeters per year. Each individual flowband of the ice shelf contains layers that are distinct in their structure. For example, the thickness of the locally accumulated layer is a function of both the time since crossing the grounding line and the thickness of the incoming ice. Features in the meteoric ice, such as distinct folds, can be traced between the two IceBridge lines located 47 km apart. The ROSETTA-ICE program will begin a systematic mapping of the Ross Ice Shelf and sub-ice topography using the IcePod system beginning in 2015. Together the new gravity-derived bathymetry and the mapping of the ice shelf structure will provide key insights into the stability of the ice shelf.

New diamidequat-type surfactants in fabrication of long-sustained theranostic nanocapsules: Colloidal stability, drug delivery and bioimaging.

PubMed

Bazylińska, Urszula; Zieliński, Wojciech; Kulbacka, Julita; Samoć, Marek; Wilk, Kazimiera A

2016-01-01

We report a new theranostic nanoformulation to transport both chemotherapeutic and imaging agents for successfully exterminating cancer cells. This strategy is based on encapsulation of colchicine (cytostatic drug) and coumarin-6 (fluorescent biomarker) in oil-core nanocarriers stabilized by diamidequat-type surfactants - N,N-dimethyl-N,N-bis[2-(N-alkylcarbamoyl) ethyl]ammonium methylsulfates (2xCnA-MS, n=8,10,12), and fabricated by the nanoprecipitation technique. The surfactants were synthesized using a technologically viable methodology and characterized. The potential of the encapsulated theranostic cargoes was evaluated in cytotoxicity studies as well as in imaging of intracellular localization, accumulation and distribution of cargoes delivered to well characterized human cancer cell lines - doxorubicin-sensitive breast (MCF-7/WT), alveolar basal epithelial (A549) and skin melanoma (MEWO) - performed by confocal laser scanning microscopy (CLSM). Backscattered profiles obtained by the turbidimetric technique were applied to evaluate physical stability of the obtained nanosystems. DLS measurements confirmed the particle diameter to be below 200nm, while AFM - its morphology and shape. Doppler electrophoresis provided a highly positive ζ-potential. UV-vis was applied to determine the encapsulation efficiencies (ca. 90%), and release profiles. The study demonstrates that the soft cationic diamidequat-type surfactants are suitable for the stabilization of theranostic nanodispersions, and they can constitute a new functional class of stabilizers of nanoparticles and have a progressive impact onto development of formulations. Furthermore, our results demonstrate excellent biocompatibility of the studied long-sustained monodisperse oil-core nanocapsules, stabilized by 2xCnA-MS, which makes them promising for cell imaging. Copyright © 2015 Elsevier B.V. All rights reserved.

Melanoma cells present high levels of HLA-A2-tyrosinase in association with instability and aberrant intracellular processing of tyrosinase.

PubMed

Michaeli, Yael; Sinik, Keren; Haus-Cohen, Maya; Reiter, Yoram

2012-04-01

Short-lived protein translation products are proposed to be a major source of substrates for major histocompatibility complex (MHC) class I antigen processing and presentation; however, a direct link between protein stability and the presentation level of MHC class I-peptide complexes has not been made. We have recently discovered that the peptide Tyr((369-377)) , derived from the tyrosinase protein is highly presented by HLA-A2 on the surface of melanoma cells. To examine the molecular mechanisms responsible for this presentation, we compared characteristics of tyrosinase in melanoma cells lines that present high or low levels of HLA-A2-Tyr((369-377)) complexes. We found no correlation between mRNA levels and the levels of HLA-A2-Tyr((369-377)) presentation. Co-localization experiments revealed that, in cell lines presenting low levels of HLA-A2-Tyr((369-377)) complexes, tyrosinase co-localizes with LAMP-1, a melanosome marker, whereas in cell lines presenting high HLA-A2-Tyr((369-377)) levels, tyrosinase localizes to the endoplasmic reticulum. We also observed differences in tyrosinase molecular weight and glycosylation composition as well as major differences in protein stability (t(1/2) ). By stabilizing the tyrosinase protein, we observed a dramatic decrease in HLA-A2-tyrosinase presentation. Our findings suggest that aberrant processing and instability of tyrosinase are responsible for the high presentation of HLA-A2-Tyr((369-377)) complexes and thus shed new light on the relationship between intracellular processing, stability of proteins, and MHC-restricted peptide presentation. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of the User Interface for AIR-Spec

NASA Astrophysics Data System (ADS)

Cervantes Alcala, E.; Guth, G.; Fedeler, S.; Samra, J.; Cheimets, P.; DeLuca, E.; Golub, L.

2016-12-01

The airborne infrared spectrometer (AIR-Spec) is an imaging spectrometer that will observe the solar corona during the 2017 total solar eclipse. This eclipse will provide a unique opportunity to observe infrared emission lines in the corona. Five spectral lines are of particular interest because they may eventually be used to measure the coronal magnetic field. To avoid infrared absorption from atmospheric water vapor, AIR-Spec will be placed on an NSF Gulfstream aircraft flying above 14.9 km. AIR-Spec must be capable of taking stable images while the plane moves. The instrument includes an image stabilization system, which uses fiber-optic gyroscopes to determine platform rotation, GPS to calculate the ephemeris of the sun, and a voltage-driven mirror to correct the line of sight. An operator monitors a white light image of the eclipse and manually corrects for residual drift. The image stabilization calculation is performed by a programmable automatic controller (PAC), which interfaces with the gyroscopes and mirror controller. The operator interfaces with a separate computer, which acquires images and computes the solar ephemeris. To ensure image stabilization is successful, a human machine interface (HMI) was developed to allow connection between the client and PAC. In order to make control of the instruments user friendly during the short eclipse observation, a graphical user interface (GUI) was also created. The GUI's functionality includes turning image stabilization on and off, allowing the user to input information about the geometric setup, calculating the solar ephemeris, refining estimates of the initial aircraft attitude, and storing data from the PAC on the operator's computer. It also displays time, location, attitude, ephemeris, gyro rates and mirror angles.

Hyperheavy nuclei in covariant density functional theory: the existence and stability

NASA Astrophysics Data System (ADS)

Gyawali, Abhinaya; Agbemava, Sylvester; Afanasjev, Anatoli

2017-09-01

The limits of existence of finite nuclei is one of interesting questions of modern low-energy nuclear physics. A lot of theoretical efforts have been dedicated to the study of superheavy nuclei with Z < 126. However, very little is known about existence and stability of hyperheavy nuclei with proton numbers Z > 126 . Almost all investigations of such nuclei consider only spherical shapes for the ground states. However, the study of superheavy nuclei indicates that such assumption leads in many cases to misinterpretation of the situation. Thus, we performed a systematic investigation of such nuclei for proton numbers from 122 up to 184 and from two-proton drip line up to two-neutron one within the axial relativistic Hartree-Bogoliubov theory. The calculations are carried out in large deformation space extending from megadeformed oblate shapes via spherical ones up to scission configuration. The stability of such nuclei against fission (including triaxial and octupole shapes) and beta-decays have been investigated and the islands of their stability have been defined. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0013037 and by Department of Energy, National Nuclear Security Administration under Award Number DE-NA0002925.

Au/Ti resistors used for Nb/Pb-alloy Josephson junctions. II. Thermal stability

NASA Astrophysics Data System (ADS)

Murakami, Masanori; Kim, K. K.

1984-10-01

In the preceding paper bilayered Au/Ti resistors were found to have excellent electrical stability during storage at room temperature after preannealing at an elevated temperature, which is essential to design logic and memory circuits of Nb/Pb-alloy Josephson junction devices. The resistors could contact directly with the Pb-alloy control lines in which Pb and In atoms which are known to intermix easily with Au atoms are contained. Since Pb and In atoms in the control lines are separated from Au atoms of the resistors by thin Ti layers, thermal stability at the contacts is a major concern for use of the Au/Ti resistor material in the Josephson devices. In the present study, surface morphology change and diffusion mechanism at the resistor/control-line contacts were studied using x-ray diffraction and scanning electron microscopy for square-shaped Au/Ti resistors covered by Pb-In layers. The samples were isothermally annealed at temperatures ranging from 353 to 423 K. The diffusion did not occur immediately after annealing at these temperatures. After the incubation period, the interdiffusion was observed to initiate at the edges of the resistors facing to the center of the cathode. Significant amounts of the In atoms in the Pb-In layers were observed to diffuse into the Au layers of the resistors, forming AuIn2 compounds under the Ti layers. By measuring growth rates of the AuIn2 layers, the diffusion coefficients and the activation energy for the layer growth were determined. Also, by analyzing changes in the In concentration in the Pb-In layers during annealing, interdiffusion coefficients of In atoms in the Pb-In layers were determined using a computer simulation technique. The activation energy was about 1.1 eV. Since these diffusion coefficients were found to be very close to those determined previously in bulk materials, the diffusion kinetics is believed to be controlled by the lattice diffusion. Based on the present results, several methods to reduce the interdiffusion between Pb-alloy and Au/Ti resistors were proposed.

The effect of undersizing and tapping on bone to implant contact and implant primary stability: A histomorphometric study on bovine ribs.

PubMed

Di Stefano, Danilo Alessio; Perrotti, Vittoria; Greco, Gian Battista; Cappucci, Claudia; Arosio, Paolo; Piattelli, Adriano; Iezzi, Giovanna

2018-06-01

Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-implant contact at insertion, bone density, and implant primary stability intra-operatively measured by a torque-measuring implant motor, when implant sites were undersized or tapped. Undersized (n=14), standard (n=13), and tapped (n=13) implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the implant motor, 40 implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-implant contact measured and statistically correlated to bone density and the integral. Bone-to-implant contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to implant contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly. The integral of the torque-depth curve provided reliable information about bone-to-implant contact and primary implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper implant primary stability, according to the planned loading protocol.

Highly precise stabilization of intracavity prism-based Er:fiber frequency comb using optical-microwave phase detector.

PubMed

Zhang, Shuangyou; Wu, Jiutao; Leng, Jianxiao; Lai, Shunnan; Zhao, Jianye

2014-11-15

In this Letter, we demonstrate a fully stabilized Er:fiber frequency comb by using a fiber-based, high-precision optical-microwave phase detector. To achieve high-precision and long-term phase locking of the repetition rate to a microwave reference, frequency control techniques (tuning pump power and cavity length) are combined together as its feedback. Since the pump power has been used for stabilization of the repetition rate, we introduce a pair of intracavity prisms as a regulator for carrier-envelope offset frequency, thereby phase locking one mode of the comb to the rubidium saturated absorption transition line. The stabilized comb performs the same high stability as the reference for the repetition rate and provides a residual frequency instability of 3.6×10(-13) for each comb mode. The demonstrated stabilization scheme could provide a high-precision comb for optical communication, direct frequency comb spectroscopy.

The effects of the dopamine stabilizer (-)-OSU6162 on aggressive and sexual behavior in rodents.

PubMed

Studer, E; Näslund, J; Westman, A; Carlsson, A; Eriksson, E

2016-03-22

The dopamine stabilizer (-)-OSU61612 dampens locomotion in rodents rendered hyperactive by exposure to a novel environment or treatment with amphetamine, but stimulates locomotion in habituated animals displaying low motor activity, tentatively exerting this profile by selectively blocking extrasynaptic D2 receptors. The major aim of the present study was to explore the possible usefulness of (-)-OSU61612 as an anti-aggressive drug. To this end, the effect of (-)-OSU61612 on isolation-induced aggression in male mice and estrous cycle-dependent aggression in female rats were studied using the resident intruder test; in addition, the possible influence of (-)-OSU61612 on sexual behavior in male mice and on elevated plus maze (EPM) performance in male rats were assessed. (-)-OSU61612 at doses influencing neither locomotion nor sexual activity reduced aggression in male mice. The effect was observed also in serotonin-depleted animals and is hence probably not caused by the antagonism of serotonin receptors displayed by the drug; refuting the possibility that it is due to 5-HT1B activation, it was also not counteracted by isamoltane. (-)-OSU61612 did not display the profile of an anxiogenic or anxiolytic drug in the EPM but caused a general reduction in activity that is well in line with the previous finding that it reduces exploratory behavior of non-habituated animals. In line with the observations in males, (-)-OSU61612 reduced estrus cycle-related aggression in female Wistar rats, a tentative animal model of premenstrual dysphoria. By stabilizing dopaminergic transmission, (-)-OSU61612 may prove useful as a well-tolerated treatment of various forms of aggression and irritability.

Copper-tolfenamic acid: evaluation of stability and anti-cancer activity.

PubMed

Hurtado, Myrna; Sankpal, Umesh T; Chhabra, Jaya; Brown, Deondra T; Maram, Rajasekhar; Patel, Rafid; Gurung, Raj K; Simecka, Jerry; Holder, Alvin A; Basha, Riyaz

2018-05-15

The non-steroidal anti-inflammatory drug, Tolfenamic acid (TA) acts as an anti-cancer agent in several adult and pediatric cancer models. Copper (Cu) is an important element with multiple biological functions and has gained interest in medical applications. Recently, [Cu(TA) 2 (bpy)] (Cu-TA) has been synthesized in order to enhance therapeutic activity. In this study, we synthesized Cu-TA using an established method, characterized it by UV visible spectroscopy and Fourier-transform infrared spectroscopy (FTIR), and tested its anti-cancer activity using twelve cell lines representing various cancers, such as Ewing sarcoma, glioblastoma, medulloblastoma, neuroblastoma, pancreatic and prostate. The anti-proliferative activity of Cu-TA was determined at 48 h post-treatment and compared with the parental compound, TA. The IC 50 values were calculated using GraphPad Prism software. The biological stability of Cu-TA was evaluated using twelve-month-old powder and six-month-old stock solution. Cardiomyocytes (H9C2) were used to test the cytotoxicity in non-malignant cells. Cu-TA showed higher anti-proliferative activity, and the IC 50 values were 30 to 80% lower when compared with TA. H9C2 cells were non-responsive to Cu-TA, suggesting that it is selective towards malignant cells. Comparison of the twelve-month-old powder and six-month-old stock solution using the Panc1 cell line showed similar IC 50 values (<5% variation), confirming the stability of Cu-TA either in powder or solution form. These findings demonstrate the potential of Cu-TA as an effective anti-cancer agent. Further studies to delineate the detailed mechanism of action of Cu-TA for specific cancer model are underway.

Green synthesis of silver nanoparticles by Ricinus communis var. carmencita leaf extract and its antibacterial study

NASA Astrophysics Data System (ADS)

Ojha, Sunita; Sett, Arghya; Bora, Utpal

2017-09-01

In this study, we report synthesis of silver nanoparticles (RcAgNPs) from silver nitrate solution using methanolic leaf extract of Ricinus communis var. carmencita. The polyphenols present in the leaves reduce Ag++ ions to Ag0 followed by a color change. Silver nanoparticle formation was ensured by surface plasmon resonance between 400 nm to 500 nm. Crystallinity of the synthesized nanoparticles was confirmed by UHRTEM, SAED and XRD analysis. The capping of phytochemicals and thermal stability of RcAgNPs were assessed by FTIR spectra and TGA analysis, respectively. It also showed antibacterial activity against both gram positive and gram negative strains. RcAgNPs were non-toxic against normal cell line (mouse fibroblast cell line L929) at lower concentrations (80 µg ml-1).

Effects of Maximal Sodium and Potassium Conductance on the Stability of Hodgkin-Huxley Model

PubMed Central

Wang, Kuanquan; Yuan, Yongfeng; Zhang, Henggui

2014-01-01

Hodgkin-Huxley (HH) equation is the first cell computing model in the world and pioneered the use of model to study electrophysiological problems. The model consists of four differential equations which are based on the experimental data of ion channels. Maximal conductance is an important characteristic of different channels. In this study, mathematical method is used to investigate the importance of maximal sodium conductance g-Na and maximal potassium conductance g-K. Applying stability theory, and taking g-Na and g-K as variables, we analyze the stability and bifurcations of the model. Bifurcations are found when the variables change, and bifurcation points and boundary are also calculated. There is only one bifurcation point when g-Na is the variable, while there are two points when g-K is variable. The (g-Na,  g-K) plane is partitioned into two regions and the upper bifurcation boundary is similar to a line when both g-Na and g-K are variables. Numerical simulations illustrate the validity of the analysis. The results obtained could be helpful in studying relevant diseases caused by maximal conductance anomaly. PMID:25104970

The Reliability and Validity of Salivation as a Measure of Individual Differences in Intrinsic Arousal. Report from the Project on Motivation and Individual Differences in Learning and Retention.

ERIC Educational Resources Information Center

Farley, Frank H.; And Others

Two studies were reported which attempted to estimate the stability and construct validity of human salivary response as a measure of individual differences (IDs) in physiological arousal. Twenty-second base line estimates and 20-second response levels to four drops of lemon juice were measured, with the former value being removed from the latter…

Constrained tracking control for nonlinear systems.

PubMed

Khani, Fatemeh; Haeri, Mohammad

2017-09-01

This paper proposes a tracking control strategy for nonlinear systems without needing a prior knowledge of the reference trajectory. The proposed method consists of a set of local controllers with appropriate overlaps in their stability regions and an on-line switching strategy which implements these controllers and uses some augmented intermediate controllers to ensure steering the system states to the desired set points without needing to redesign the controller for each value of set point changes. The proposed approach provides smooth transient responses despite switching among the local controllers. It should be mentioned that the stability regions of the proposed controllers could be estimated off-line for a range of set-point changes. The efficiencies of the proposed algorithm are illustrated via two example simulations. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Effect of turbulent eddy viscosity on the unstable surface mode above an acoustic liner

NASA Astrophysics Data System (ADS)

Marx, David; Aurégan, Yves

2013-07-01

Lined ducts are used to reduce noise radiation from ducts in turbofan engines. In certain conditions they may sustain hydrodynamic instabilities. A local linear stability analysis of the flow in a 2D lined channel is performed using a numerical integration of the governing equations. Several model equations are used, one of them taking into account turbulent eddy viscosity, and a realistic turbulent mean flow profile is used that vanishes at the wall. The stability analysis results are compared to published experimental results. Both the model and the experiments show the existence of an unstable mode, and the importance of taking into account eddy viscosity in the model is shown. When this is done, quantities such as the growth rate and the velocity eigenfunctions are shown to agree correctly.

On the 'flip-flop' instability of Bondi-Hoyle accretion flows

NASA Technical Reports Server (NTRS)

Livio, Mario; Soker, Noam; Matsuda, Takuya; Anzer, Ulrich

1991-01-01

A simple physical interpretation is advanced by means of an analysis of the shock cone in the accretion flows past a compact object and with an examination of the accretion-line stability analyses. The stability of the conical shock is examined against small angular deflections with attention given to several simplifying assumptions. A line instability is identified in the Bondi-Hoyle accretion flows that leads to the formation of a large opening-angle shock. When the opening angle becomes large the instability becomes irregular oscillation. The analytical methodology is compared to previous numerical configurations that demonstrate different shock morphologies. The Bondi-Hoyle accretion onto a compact object is concluded to generate a range of nonlinear instabilities in both homogeneous and inhomogeneous cases with a quasiperiodic oscillation in the linear regime.

Caudal Septal Stabilization Suturing Technique to Treat Crooked Noses.

PubMed

Baykal, Bahadir; Erdim, Ibrahim; Guvey, Ali; Oghan, Fatih; Kayhan, Fatma Tulin

2016-10-01

To rotate the nasal axis and septum to the midline using an L-strut graft and a novel caudal septal stabilization suturing technique to treat crooked noses. Thirty-six patients were included in the study. First, an L-strut graft was prepared by excising the deviated cartilage site in all patients. Second, multiple stabilization suturing, which we describe as a caudal septal stabilization suturing technique with a "fishing net"-like appearance, was applied between the anterior nasal spine and caudal septum in all patients. This new surgical technique, used to rotate the caudal septum, was applied to 22 I-type and 14 C-type crooked noses. Correction rates for the crooked noses were compared between the 2 inclination types with angular estimations. Deviation angles were measured using the AutoCAD 2012 software package and frontal (anterior) views, with the Frankfurt horizontal line parallel to the ground. Nasal axis angles showing angle improvement graded 4 categories as excellent, good, acceptable, and unsuccessful for evaluations at 6 months after surgery in the study. The success rate in the C-type nasal inclination was 86.7% (±21.9) and 88% (±16.7) in the I-type. The overall success rate of L-strut grafting and caudal septal stabilization suturing in crooked nose surgeries was 87.5% (±18.6). "Unsuccessful" results were not reported in any of the patients. L-strut grafting and caudal septal stabilization suturing techniques are efficacious in crooked noses according to objective measurement analysis results. However, a longer follow-up duration in a larger patient population is needed.

Development of a wavelength stabilized seed laser system for an airborne water vapour lidar experiment

NASA Astrophysics Data System (ADS)

Schwarzer, H.; Börner, A.; Fix, A.; Günther, B.; Hübers, H.-W.; Raugust, M.; Schrandt, F.; Wirth, M.

2007-09-01

At the German Aerospace Center an airborne multi-wavelength differential absorption LIDAR for the measurement of atmospheric water vapour is currently under development. This instrument will enable the retrieval of the complete humidity profile from the surface up to the lowermost stratosphere with high vertical and horizontal resolution at a systematic error below 5%. The LIDAR will work in the wavelength region around 935 nm at three different water vapour absorption lines and one reference wavelength. A major sub-system of this instrument is a highly frequency stabilized seed laser system for the optical parametrical oscillators which generate the narrowband high energy light pulses. The development of the seed laser system includes the control software, the electronic control unit and the opto-mechanical layout. The seed lasers are Peltier-cooled distributed feedback laser diodes with bandwidths of about 30 MHz, each one operating for 200 μs before switching to the next one. The required frequency stability is +/- 30 MHz ≅ +/- 10 -4 nm under the rough environmental conditions aboard an aircraft. It is achieved by locking the laser wavelength to a water vapour absorption line. The paper describes the opto-mechanical layout of the seed laser system, the stabilization procedure and the results obtained with this equipment.

Fast steering and quick positioning of large field-of-regard, two-axis, four-gimbaled sight

NASA Astrophysics Data System (ADS)

Ansari, Zahir Ahmed; Nigam, Madhav Ji; Kumar, Avnish

2017-07-01

Fast steering and quick positioning are prime requirements of the current electro-optical tracking system to achieve quick target acquisition. A scheme has been proposed for realizing these features using two-axis, four-gimbaled sight. For steering the line of sight in the stabilization mode, outer gimbal is slaved to the gyro stabilized inner gimbal. Typically, the inner gimbals have direct drives and outer gimbals have geared drives, which result in a mismatch in the acceleration capability of their servo loops. This limits the allowable control bandwidth for the inner gimbal. However, to achieve high stabilization accuracy, high bandwidth control loops are essential. This contradictory requirement has been addressed by designing a suitable command conditioning module for the inner gimbals. Also, large line-of-sight freedom in pitch axis is required to provide a wide area surveillance capacity for airborne application. This leads to a loss of freedom along the yaw axis as the pitch angle goes beyond 70 deg or so. This is addressed by making the outer gimbal master after certain pitch angle. Moreover, a mounting scheme for gyro has been proposed to accomplish yaw axis stabilization for 110-deg pitch angle movement with a single two-axis gyro.

Force direction patterns promote whole body stability even in hip-flexed walking, but not upper body stability in human upright walking

NASA Astrophysics Data System (ADS)

Müller, Roy; Rode, Christian; Aminiaghdam, Soran; Vielemeyer, Johanna; Blickhan, Reinhard

2017-11-01

Directing the ground reaction forces to a focal point above the centre of mass of the whole body promotes whole body stability in human and animal gaits similar to a physical pendulum. Here we show that this is the case in human hip-flexed walking as well. For all upper body orientations (upright, 25°, 50°, maximum), the focal point was well above the centre of mass of the whole body, suggesting its general relevance for walking. Deviations of the forces' lines of action from the focal point increased with upper body inclination from 25 to 43 mm root mean square deviation (RMSD). With respect to the upper body in upright gait, the resulting force also passed near a focal point (17 mm RMSD between the net forces' lines of action and focal point), but this point was 18 cm below its centre of mass. While this behaviour mimics an unstable inverted pendulum, it leads to resulting torques of alternating sign in accordance with periodic upper body motion and probably provides for low metabolic cost of upright gait by keeping hip torques small. Stabilization of the upper body is a consequence of other mechanisms, e.g. hip reflexes or muscle preflexes.

Wobble pairs of the HDV ribozyme play specific roles in stabilization of active site dynamics.

PubMed

Sripathi, Kamali N; Banáš, Pavel; Réblová, Kamila; Šponer, Jiří; Otyepka, Michal; Walter, Nils G

2015-02-28

The hepatitis delta virus (HDV) is the only known human pathogen whose genome contains a catalytic RNA motif (ribozyme). The overall architecture of the HDV ribozyme is that of a double-nested pseudoknot, with two GU pairs flanking the active site. Although extensive studies have shown that mutation of either wobble results in decreased catalytic activity, little work has focused on linking these mutations to specific structural effects on catalytic fitness. Here we use molecular dynamics simulations based on an activated structure to probe the active site dynamics as a result of wobble pair mutations. In both wild-type and mutant ribozymes, the in-line fitness of the active site (as a measure of catalytic proficiency) strongly depends on the presence of a C75(N3H3+)N1(O5') hydrogen bond, which positions C75 as the general acid for the reaction. Our mutational analyses show that each GU wobble supports catalytically fit conformations in distinct ways; the reverse G25U20 wobble promotes high in-line fitness, high occupancy of the C75(N3H3+)G1(O5') general-acid hydrogen bond and stabilization of the G1U37 wobble, while the G1U37 wobble acts more locally by stabilizing high in-line fitness and the C75(N3H3+)G1(O5') hydrogen bond. We also find that stable type I A-minor and P1.1 hydrogen bonding above and below the active site, respectively, prevent local structural disorder from spreading and disrupting global conformation. Taken together, our results define specific, often redundant architectural roles for several structural motifs of the HDV ribozyme active site, expanding the known roles of these motifs within all HDV-like ribozymes and other structured RNAs.

Wobble Pairs of the HDV Ribozyme Play Specific Roles in Stabilization of Active Site Dynamics

PubMed Central

Sripathi, Kamali N.; Banáš, Pavel; Reblova, Kamila; Šponer, Jiři; Otyepka, Michal

2015-01-01

The hepatitis delta virus (HDV) is the only known human pathogen whose genome contains a catalytic RNA motif (ribozyme). The overall architecture of the HDV ribozyme is that of a double-nested pseudoknot, with two GU pairs flanking the active site. Although extensive studies have shown that mutation of either wobble results in decreased catalytic activity, little work has focused on linking these mutations to specific structural effects on catalytic fitness. Here we use molecular dynamics simulations based on an activated structure to probe the active site dynamics as a result of wobble pair mutations. In both wild-type and mutant ribozymes, the in-line fitness of the active site (as a measure of catalytic proficiency) strongly depends on the presence of a C75(N3H3+)N1(O5′) hydrogen bond, which positions C75 as the general acid for the reaction. Our mutational analyses show that each GU wobble supports catalytically fit conformations in distinct ways; the reverse G25U20 wobble promotes high in-line fitness, high occupancy of the C75(N3H3+)G1(O5′) general-acid hydrogen bond and stabilization of the G1U37 wobble, while the G1U37 wobble acts more locally by stabilizing high in-line fitness and the C75(N3H3+)G1(O5′) hydrogen bond. We also find that stable type I A-minor and P1.1 hydrogen bonding above and below the active site, respectively, prevent local structural disorder from spreading and disrupting global conformation. Taken together, our results define specific, often redundant architectural roles for several structural motifs of the HDV ribozyme active site, expanding the known roles of these motifs within all HDV-like ribozymes and other structured RNAs. PMID:25631765

Spatially Developing Secondary Instabilities and Attachment Line Instability in Supersonic Boundary Layers

NASA Technical Reports Server (NTRS)

Li, Fei; Choudhari, Meelan M.

2008-01-01

This paper reports on progress towards developing a spatial stability code for compressible shear flows with two inhomogeneous directions, such as crossflow dominated swept-wing boundary layers and attachment line flows. Certain unique aspects of formulating a spatial, two-dimensional eigenvalue problem for the secondary instability of finite amplitude crossflow vortices are discussed. A primary test case used for parameter study corresponds to the low-speed, NLF-0415(b) airfoil configuration as tested in the ASU Unsteady Wind Tunnel, wherein a spanwise periodic array of roughness elements was placed near the leading edge in order to excite stationary crossflow modes with a specified fundamental wavelength. The two classes of flow conditions selected for this analysis include those for which the roughness array spacing corresponds to either the naturally dominant crossflow wavelength, or a subcritical wavelength that serves to reduce the growth of the naturally excited dominant crossflow modes. Numerical predictions are compared with the measured database, both as indirect validation for the spatial instability analysis and to provide a basis for comparison with a higher Reynolds number, supersonic swept-wing configuration. Application of the eigenvalue analysis to the supersonic configuration reveals that a broad spectrum of stationary crossflow modes can sustain sufficiently strong secondary instabilities as to potentially cause transition over this configuration. Implications of this finding for transition control in swept wing boundary layers are examined. Finally, extension of the spatial stability analysis to supersonic attachment line flows is also considered.

Properties of r-process nuclei near N=82 shell closure

NASA Astrophysics Data System (ADS)

Farhan, A. R.; Sharma, M. M.

2004-10-01

We have studied properties of nuclei in r-process region near N=82 shell closure with the RMF calculations in a deformed basis using the force NL-SV1 that includes vector self-coupling of w meson. It is shown that nuclei above N=82 in several isotopic chains in the r-process region exhibit an onset of deformation beyond the drip line. Consequently, induced by the deformation these nuclei show an extra stability above the shell closure. This stability of nuclei is expected to contribute to the r-process nucleosynthesis of nuclei below the abundance peak at A ˜130. A comparison with the mass formulae shows that our microscopic calculations with NL-SV1 show a decrease of shell strength with increase in isospin. This is in contrast to the strong shell effects shown by FRDM and ETF-SI in going to the drip line. The stiffness of the shell structure with FRDM and ETF-SI is known to lead to a shortfall in the r-process abundances. This shortcoming of the above mass formulae has inspired an ad-hoc inclusion of shell quenching in the mass formula ETF-SI(Q) with a view to better reproduce the r-process abundances. In comparison, our model shows a decrease of the shell strength in going from the r-process path to the drip line. Therefore, this represents a natural behaviour as required by r-process abundances. It may, however, be confirmed in network chain calculations using inputs from our microscopic model.

The Hidden Side of Disodium Cromolyn: from Mast Cell Stabilizer to an Angiogenic Factor and Antitumor Agent.

PubMed

Cimpean, Anca Maria; Raica, Marius

2016-12-01

Scattered data suggested that disodium cromolyn, well known as a mast cell stabilizer shows some effects on tumor cells and tumor-associated newly formed vascular networks. Most of these studies used tumor cell lines assessed by in vitro studies. Nor disodium cromolyn effects on melanoma cell lines were studied yet, neither its influence on recruited tumor blood vessels or angiogenic growth factors expression. We designed here a study regarding disodium cromolyn effects on A375 melanoma tumor cells implanted on chick embryo chorioallantoic membrane (CAM) and on blood vessels recruited by the experimental melanoma in the absence of mast cells, knowing that within CAM, the existence of mast cells are not certified yet. We also assessed the role of disodium cromolyn on the expression of several angiogenic growth factors. Disodium cromoglycate differentially acts on tumor cells and blood vessels. Extensive necrotic areas of experimental melanoma together with an increased number of peritumor blood vessels were observed in treated specimens as compared with untreated tumors. Disodium cromolyn inhibited VEGF and PDGF-BB expression, and had no effects on EG VEGF expression between treated and non treated specimens in a mast cells free microenvironment. Our results sustain the direct antitumor effects of sodium cromolyn and suggest the involvement of several growth factors in the recruitment of tumor vessels by A375 melanoma tumor cells. The expression of growth factors is differentially influenced by sodium cromolyn treatment.

In Silico Estimation of Translation Efficiency in Human Cell Lines: Potential Evidence for Widespread Translational Control

PubMed Central

Stevens, Stewart G.; Brown, Chris M

2013-01-01

Recently large scale transcriptome and proteome datasets for human cells have become available. A striking finding from these studies is that the level of an mRNA typically predicts no more than 40% of the abundance of protein. This correlation represents the overall figure for all genes. We present here a bioinformatic analysis of translation efficiency – the rate at which mRNA is translated into protein. We have analysed those human datasets that include genome wide mRNA and protein levels determined in the same study. The analysis comprises five distinct human cell lines that together provide comparable data for 8,170 genes. For each gene we have used levels of mRNA and protein combined with protein stability data from the HeLa cell line to estimate translation efficiency. This was possible for 3,990 genes in one or more cell lines and 1,807 genes in all five cell lines. Interestingly, our analysis and modelling shows that for many genes this estimated translation efficiency has considerable consistency between cell lines. Some deviations from this consistency likely result from the regulation of protein degradation. Others are likely due to known translational control mechanisms. These findings suggest it will be possible to build improved models for the interpretation of mRNA expression data. The results we present here provide a view of translation efficiency for many genes. We provide an online resource allowing the exploration of translation efficiency in genes of interest within different cell lines (http://bioanalysis.otago.ac.nz/TranslationEfficiency). PMID:23460887

Microwave Hybrid Integrated Circuit Applicatins of High Transition Temperature Superconductor

NASA Astrophysics Data System (ADS)

Lu, Shih-Lin

This research work involves microwave characterization of high Tc superconducting (HTS) thin film using microstrip ring resonators, studying the nonlinear properties of HTS thin film transmission lines using two-tone intermodulation technique, coupling mechanisms and coupling factors of microstrip ring resonators side coupled to a microstrip line, two-port S-parameters measurements of GaAs MESFET at low temperature, and the design and implementation of hybrid ring resonator stabilized microwave oscillator using both metal films and superconducting films. A microstrip ring resonators operating at 10 GHz have been fabricated from YBCO HTS thin films deposited on one side of LaAl_2O_3 substrates. Below 60^circ Kelvin the measured unloaded Q of the HTS thin film microstrip ring resonators are more than 1.5 times that of gold film resonators. The two distinct but very close resonance peaks of a ring resonator side coupled to a microstrip line are experimentally identified as due to odd-mode and even-mode coupling. These two mechanisms have different characteristic equivalent circuit models and lead to different coupling coefficients and loaded resonance frequencies. The coupling factors for the two coupling modes are calculated using piecewise coupled line approximations. The two-port S-parameters measurement techniques and GaAs MESFET low temperature DC and microwave characteristics have been investigated. A system errors model including the errors caused by the line constriction at low temperature has been proposed and a temperature errors correction procedure has been developed for the two-port microwave S-parameters measurements at low temperature. The measured GaAs MESFET DC characteristics shows a 20% increase in transconductance at 77^circ K. There is also a 2 db increase in /S21/ at 77^circ K. The microwave oscillator stabilized with both metal and HTS thin film ring resonators have been studied. The tuning ability of the oscillator by a varactor diode has also been investigated. The phase noise performance of one side of the high Tc film oscillator does not show appreciable improvement over the gold film oscillator. With a varactor diode, the oscillator tuning range can be 300 MHz more. Two-tone intermodulation distortion (IMD) at 6.3 GHz in an HTS YBCO superconducting thin film microstrip transmission line on LaAl_2O _3 substrates are experimentally studied. At fixed input power, the 3rd order IMD power as function of temperature shows a minimum at a temperature around 60^circ Kelvin. With DC current applied, the second order IMD is observed and shows a strong functional dependance to the applied DC current and input power.

Screening of anionic-modified polymers in terms of stability, disintegration, and swelling behavior.

PubMed

Laffleur, Flavia; Ijaz, Muhammad; Menzel, Claudia

2017-11-01

This study aimed to screen the stability, disintegration, and swelling behavior of chemically modified anionic polymers. Investigated polymers were well-known and widely used staples of the pharmaceutical and medical field, namely, alginate (AL), carboxymethyl cellulose (CMC), polycarbophil (PC), and hyaluronic acid (HA). On the basis of amide bond formation between the carboxylic acid moieties of anionic polymers and the primary amino group of the modification ligand cysteine (CYS), the modified polymers were obtained. Unmodified polymers served as controls throughout all studies. With the Ellman's assay, modification degrees were determined of synthesized polymeric excipients. Stability assay in terms of erosion study at physiological conditions were performed. Moreover, water uptake of compressed polymeric discs were evaluated and further disintegration studies according to the USP were carried out to define the potential ranking. Results ranking figured out PCCYS > CMCCYS > HACYS > ALCYS in terms of water uptake capacity compared to respective controls. Cell viability assays on Caco-2 cell line as well as on RPMI 2650 (ATTC CCL30) proved modification not being harmful to those. Due to the results of this study, an intense screening of prominent anionic polymer derivate was performed in order to help the pharmaceutical research for the best choice of polymeric excipients for developments of controlled drug release systems.

Dynamic motion modes of high temperature superconducting maglev on a 45-m long ring test line

NASA Astrophysics Data System (ADS)

Lei, W. Y.; Qian, N.; Zheng, J.; Jin, L. W.; Zhang, Y.; Deng, Z. G.

2017-10-01

With the development of high temperature superconducting (HTS) maglev, studies on the running stability have become more and more significant to ensure the operation safety. An experimental HTS maglev vehicle was tested on a 45-m long ring test line under the speed from 4 km/h to 20 km/h. The lateral and vertical acceleration signals of each cryostat were collected by tri-axis accelerometers in real time. By analyzing the phase relationship of acceleration signals on the four cryostats, several typical motion modes of the HTS maglev vehicle, including lateral, yaw, pitch and heave motions were observed. This experimental finding is important for the next improvement of the HTS maglev system.

Comparing the line broadened quasilinear model to Vlasov code

NASA Astrophysics Data System (ADS)

Ghantous, K.; Berk, H. L.; Gorelenkov, N. N.

2014-03-01

The Line Broadened Quasilinear (LBQ) model is revisited to study its predicted saturation level as compared with predictions of a Vlasov solver BOT [Lilley et al., Phys. Rev. Lett. 102, 195003 (2009) and M. Lilley, BOT Manual. The parametric dependencies of the model are modified to achieve more accuracy compared to the results of the Vlasov solver both in regards to a mode amplitude's time evolution to a saturated state and its final steady state amplitude in the parameter space of the model's applicability. However, the regions of stability as predicted by LBQ model and BOT are found to significantly differ from each other. The solutions of the BOT simulations are found to have a larger region of instability than the LBQ simulations.

Performance characteristics of qualified cell lines for isolation and propagation of influenza viruses for vaccine manufacturing

PubMed Central

Donis, Ruben O.; Chen, i-Mei; Davis, C Todd; Foust, Angie; Hossain, M. Jaber; Johnson, Adam; Klimov, Alexander; Loughlin, Rosette; Xu, Xiyan; Tsai, Theodore; Blayer, Simone; Trusheim, Heidi; Colegate, Tony; Fox, John; Taylor, Beverly; Hussain, Althaf; Barr, Ian; Baas, Chantal; Louwerens, Jaap; Geuns, Ed; Lee, Min-Shi; Venhuizen, odewijk; Neumeier, Elisabeth; Ziegler, Thedi

2018-01-01

Cell culture is now available as a method for the production of influenza vaccines in addition to eggs. In accordance with currently accepted practice, viruses recommended as candidates for vaccine manufacture are isolated and propagated exclusively in hens' eggs prior to distribution to manufacturers. Candidate vaccine viruses isolated in cell culture are not available to support vaccine manufacturing in mammalian cell bioreactors so egg-derived viruses have to be used. Recently influenza A (H3N2) viruses have been difficult to isolate directly in eggs. As mitigation against this difficulty, and the possibility of no suitable egg-isolated candidate viruses being available, it is proposed to consider using mammalian cell lines for primary isolation of influenza viruses as candidates for vaccine production in egg and cell platforms. To investigate this possibility, we tested the antigenic stability of viruses isolated and propagated in cell lines qualified for influenza vaccine manufacture and subsequently investigated antigen yields of such viruses in these cell lines at pilot-scale. Twenty influenza A and B-positive, original clinical specimens were inoculated in three MDCK cell lines. The antigenicity of recovered viruses was tested by hemagglutination inhibition using ferret sera against contemporary vaccine viruses and the amino acid sequences of the hemagglutinin and neuraminidase were determined. MDCK cell lines proved to be highly sensitive for virus isolation. Compared to the virus sequenced from the original specimen, viruses passaged three times in the MDCK lines showed up to 2 amino acid changes in the hemagglutinin. Antigenic stability was also established by hemagglutination inhibition titers comparable to those of the corresponding reference virus. Viruses isolated in any of the three MDCK lines grew reasonably well but variably in three MDCK cells and in VERO cells at pilot-scale. These results indicate that influenza viruses isolated in vaccine certified cell lines may well qualify for use in vaccine production. PMID:24975811

Performance characteristics of qualified cell lines for isolation and propagation of influenza viruses for vaccine manufacturing.

PubMed

Donis, Ruben O; Davis, C Todd; Foust, Angie; Hossain, M Jaber; Johnson, Adam; Klimov, Alexander; Loughlin, Rosette; Xu, Xiyan; Tsai, Theodore; Blayer, Simone; Trusheim, Heidi; Colegate, Tony; Fox, John; Taylor, Beverly; Hussain, Althaf; Barr, Ian; Baas, Chantal; Louwerens, Jaap; Geuns, Ed; Lee, Min-Shi; Venhuizen, Odewijk; Neumeier, Elisabeth; Ziegler, Thedi

2014-11-12

Cell culture is now available as a method for the production of influenza vaccines in addition to eggs. In accordance with currently accepted practice, viruses recommended as candidates for vaccine manufacture are isolated and propagated exclusively in hens' eggs prior to distribution to manufacturers. Candidate vaccine viruses isolated in cell culture are not available to support vaccine manufacturing in mammalian cell bioreactors so egg-derived viruses have to be used. Recently influenza A (H3N2) viruses have been difficult to isolate directly in eggs. As mitigation against this difficulty, and the possibility of no suitable egg-isolated candidate viruses being available, it is proposed to consider using mammalian cell lines for primary isolation of influenza viruses as candidates for vaccine production in egg and cell platforms. To investigate this possibility, we tested the antigenic stability of viruses isolated and propagated in cell lines qualified for influenza vaccine manufacture and subsequently investigated antigen yields of such viruses in these cell lines at pilot-scale. Twenty influenza A and B-positive, original clinical specimens were inoculated in three MDCK cell lines. The antigenicity of recovered viruses was tested by hemagglutination inhibition using ferret sera against contemporary vaccine viruses and the amino acid sequences of the hemagglutinin and neuraminidase were determined. MDCK cell lines proved to be highly sensitive for virus isolation. Compared to the virus sequenced from the original specimen, viruses passaged three times in the MDCK lines showed up to 2 amino acid changes in the hemagglutinin. Antigenic stability was also established by hemagglutination inhibition titers comparable to those of the corresponding reference virus. Viruses isolated in any of the three MDCK lines grew reasonably well but variably in three MDCK cells and in VERO cells at pilot-scale. These results indicate that influenza viruses isolated in vaccine certified cell lines may well qualify for use in vaccine production. Published by Elsevier Ltd.

Increasing the stability of the articulated lorry at braking by locking the fifth wheel coupling

NASA Astrophysics Data System (ADS)

Skotnikov, G. I.; Jileykin, M. M.; Komissarov, A. I.

2018-02-01

The jackknifing of the articulated lorry is determined by the loss of stability with respect to the vertical axis of the fifth wheel coupling, which can be caused by the failure of the brake system, the displacement of the center of mass of the semitrailer or tractor from the longitudinal axis of the vehicle, the road parameters (longitudinal and transverse slopes), the difference in the friction coefficients under the sides of the articulated lorry. In this regard, the issue of creating devices that prevent the jackknifing, and their control systems is important. A method is proposed for maintaining the stability of the movement of articulated lorry when braking both on a straight line and in a turn by blocking the relative rotation of the tractor and the trailer. Blocking occurs due to the creation of a stabilizing moment in the direction opposite to the angular rate of folding. To test the developed algorithm for locking the fifth wheel coupling, a mathematical model of the spatial motion of the articulated lorry was developed, including the models of interaction of an elastic tire with a rigid terrain, suspension systems, transmission, steering, fifth-wheel coupling. The efficiency and effectiveness of the coupling locking control system is proved by comparing the results of the simulation of a straight-line braking and braking in turn. It is shown that the application of the control system significantly increases the stability of the road train.

Cloning of transgenic tobacco BY-2 cells; an efficient method to analyse and reduce high natural heterogeneity of transgene expression.

PubMed

Nocarova, Eva; Fischer, Lukas

2009-04-22

Phenotypic characterization of transgenic cell lines, frequently used in plant biology studies, is complicated because transgene expression in individual cells is often heterogeneous and unstable. To identify the sources and to reduce this heterogeneity, we transformed tobacco (Nicotiana tabacum L.) BY-2 cells with a gene encoding green fluorescent protein (GFP) using Agrobacterium tumefaciens, and then introduced a simple cloning procedure to generate cell lines derived from the individual transformed cells. Expression of the transgene was monitored by analysing GFP fluorescence in the cloned lines and also in lines obtained directly after transformation. The majority ( approximately 90%) of suspension culture lines derived from calli that were obtained directly from transformation consisted of cells with various levels of GFP fluorescence. In contrast, nearly 50% of lines generated by cloning cells from the primary heterogeneous suspensions consisted of cells with homogenous GFP fluorescence. The rest of the lines exhibited "permanent heterogeneity" that could not be resolved by cloning. The extent of fluorescence heterogeneity often varied, even among genetically identical clones derived from the primary transformed lines. In contrast, the offspring of subsequent cloning of the cloned lines was uniform, showing GFP fluorescence intensity and heterogeneity that corresponded to the original clone. The results demonstrate that, besides genetic heterogeneity detected in some lines, the primary lines often contained a mixture of epigenetically different cells that could be separated by cloning. This indicates that a single integration event frequently results in various heritable expression patterns, which are probably accidental and become stabilized in the offspring of the primary transformed cells early after the integration event. Because heterogeneity in transgene expression has proven to be a serious problem, it is highly advisable to use transgenes tagged with a visual marker for BY-2 transformation. The cloning procedure can be used not only for efficient reduction of expression heterogeneity of such transgenes, but also as a useful tool for studies of transgene expression and other purposes.

Analysis of Induced Pluripotent Stem Cells from a BRCA1 Mutant Family

PubMed Central

Soyombo, Abigail A.; Wu, Yipin; Kolski, Lauren; Rios, Jonathan J.; Rakheja, Dinesh; Chen, Alice; Kehler, James; Hampel, Heather; Coughran, Alanna; Ross, Theodora S.

2013-01-01

Summary Understanding BRCA1 mutant cancers is hampered by difficulties in obtaining primary cells from patients. We therefore generated and characterized 24 induced pluripotent stem cell (iPSC) lines from fibroblasts of eight individuals from a BRCA1 5382insC mutant family. All BRCA1 5382insC heterozygous fibroblasts, iPSCs, and teratomas maintained equivalent expression of both wild-type and mutant BRCA1 transcripts. Although no difference in differentiation capacity was observed between BRCA1 wild-type and mutant iPSCs, there was elevated protein kinase C-theta (PKC-theta) in BRCA1 mutant iPSCs. Cancer cell lines with BRCA1 mutations and hormone-receptor-negative breast cancers also displayed elevated PKC-theta. Genome sequencing of the 24 iPSC lines showed a similar frequency of reprogramming-associated de novo mutations in BRCA1 mutant and wild-type iPSCs. These data indicate that iPSC lines can be derived from BRCA1 mutant fibroblasts to study the effects of the mutation on gene expression and genome stability. PMID:24319668

Cervical spinal motion during intubation: efficacy of stabilization maneuvers in the setting of complete segmental instability.

PubMed

Lennarson, P J; Smith, D W; Sawin, P D; Todd, M M; Sato, Y; Traynelis, V C

2001-04-01

The purpose of this study was to characterize and compare segmental cervical motion during orotracheal intubation in cadavers with and without a complete subaxial injury, as well as to examine the efficacy of commonly used stabilization techniques in limiting that motion. Intubation procedures were performed in 10 fresh human cadavers in which cervical spines were intact and following the creation of a complete C4-5 ligamentous injury. Movement of the cervical spine during direct laryngoscopy and intubation was recorded using video fluoroscopy and examined under the following conditions: 1) without stabilization; 2) with manual in-line cervical immobilization; and 3) with Gardner-Wells traction. Subsequently, segmental angular rotation, subluxation, and distraction at the injured C4-5 level were measured from digitized frames of the recorded video fluoroscopy. After complete C4-5 destabilization, the effects of attempted stabilization on distraction, angulation, and subluxation were analyzed. Immobilization effectively eliminated distraction, and diminished angulation, but increased subluxation. Traction significantly increased distraction, but decreased angular rotation and effectively eliminated subluxation. Orotracheal intubation without stabilization had intermediate results, causing less distraction than traction, less subluxation than immobilization, but increased angulation compared with either intervention. These results are discussed in terms of both statistical and clinical significance and recommendations are made.

Dipolar excitation in the third stability region.

PubMed

Konenkov, Nikolai V; Chernyak, Eugenii Ya; Stepanov, Vladimir A

Dipole resonant excitation of ions creates instability bands which follow iso-β lines where β is the characteristic exponent (stability parameter). Instability bands are exited most effectively on the fundamental frequency π= βΩ/2. Here π is the angle resonance frequency of the dipolar voltage applied to x or y pair rods of the analyzer, and Ω is the angle frequency of the main drive voltage. Our goal is to study the mass peak shape in the third stability region with dipolar resonance excitation of the instability band with respect to the resonance frequency π and the dipolar potential amplitude. Numerical integration of the ion motion equations with a given ion source emittance is used to investigate peak shapes and ion transmission. We show that it is possible to vary the resolution power at any part of the third stability region. A change of the dipolar potential phase leads to a periodical variation of the resolution with period π.The most effective dipolar excitation in the y direction is along βy near the stability boundary. The mass peak shape is calculated also for a quadrupole with round rods. The best peak shape (small tails and high resolution) takes place for the rod set with r/r0=1.130. Dipolar excitation increases the transmission by approximately 5-10% at a given resolution.

Synthesis and biological evaluation of some novel triazole hybrids of curcumin mimics and their selective anticancer activity against breast and prostate cancer cell lines.

PubMed

Mandalapu, Dhanaraju; Saini, Karan S; Gupta, Sonal; Sharma, Vikas; Yaseen Malik, Mohd; Chaturvedi, Swati; Bala, Veenu; Hamidullah; Thakur, Subhadra; Maikhuri, Jagdamba P; Wahajuddin, Muhammad; Konwar, Rituraj; Gupta, Gopal; Sharma, Vishnu Lal

2016-09-01

The anti-cancer property of curcumin, an active component of turmeric, is limited due to its poor solubility, stability and bioavailability. To enhance its efficacy, we designed a novel series of twenty-four monocarbonyl curcumin analogue-1,2,3-triazole conjugates and evaluated their anti-cancer activity towards endocrine related cancers. The new compounds (17-40) were synthesized through CuAAC click reaction and SAR analysis carried out. Out of these all, compound 17 showed most significant anti-cancer activity against prostate cancer cells with IC50 values of 8.8μM and 9.5μM in PC-3 and DU-145 cells, respectively. Another compound 26 showed significant anti-cancer activity against breast cancer cells with IC50 of 6μM, 10μM and 6.4μM in MCF-7, MDA-MB-231 and 4T1 cells, respectively while maintaining low toxicity towards non-cancer originated cell line, HEK-293. Compounds 17 and 26 arrested cell cycle and induced mitochondria-mediated apoptosis in cancer cells. Further, both of these compounds significantly down-regulated cell proliferation marker (PCNA), inhibited activation of cell survival protein (Akt phosphorylation), upregulated pro-apoptotic protein (Bax) and down-regulated anti-apoptotic protein (Bcl-2) in their respective cell lines. In addition, in vitro stability, solubility and plasma binding studies of the compounds 17 and 26 showed them to be metabolically stable. Thus, this study identified two new curcumin monocarbonyl-1,2,3-triazole conjugate compounds with more potent activity than curcumin against breast and prostate cancers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Establishment and characterization of fetal fibroblast cell lines for generating human lysozyme transgenic goats by somatic cell nuclear transfer.

PubMed

Liu, Jun; Luo, Yan; Zheng, Liming; Liu, Qingqing; Yang, Zhongcai; Wang, Yongsheng; Su, Jianmin; Quan, Fusheng; Zhang, Yong

2013-10-01

This study was performed to qualify goat fetal fibroblast (GFF) cell lines for genetic modification and somatic cell nuclear transfer (SCNT) to produce human lysozyme (hLYZ) transgenic goats. Nine GFF cell lines were established from different fetuses, and the proliferative lifespan and chromosomal stability were analyzed. The results suggested that cell lines with a longer lifespan had stable chromosomes compared with those of cells lines with a shorter lifespan. According to the proliferative lifespan, we divided GFF cell lines into two groups: cell lines with a long lifespan (GFF1/2/7/8/9; group L) and cell lines with a short lifespan (GFF3/4/5/6; group S). Next, a hLYZ expression vector was introduced into these cell lines by electroporation. The efficiencies of colony formation, expansion in culture, and the quality of transgenic clonal cell lines were significant higher in group L than those in group S. The mean fusion rate and blastocyst rate in group L were higher than those in group S (80.3 ± 1.7 vs. 65.1 ± 4.2 % and 19.5 ± 0.6 vs. 15.1 ± 1.1 %, respectively, P < 0.05). After transferring cloned embryos into the oviducts of recipient goats, three live kids were born. PCR and Southern blot analyses confirmed integration of the transgene in cloned goats. In conclusion, the lifespan of GFF cell lines has a major effect on the efficiency to produce transgenic cloned goats. Therefore, the proliferative lifespan of primary cells may be used as a criterion to characterize the quality of cell lines for genetic modification and SCNT.

Vapor bridges between solid substrates in the presence of the contact line pinning effect: Stability and capillary force

NASA Astrophysics Data System (ADS)

Liu, Yawei; Zhang, Xianren

2016-12-01

In this work, we focus on investigating how nanobubbles mediate long-range interaction between neighboring solid substrates in the presence of the contact line pinning effect caused by surface heterogeneities. Using the constrained lattice density functional theory (LDFT), we prove that the nanobubbles, which take the form of vapor bridges here, are stabilized by the pinning effect if the separation between two substrates is less than a critical distance. The critical distance strongly depends on the chemical potential (i.e., the degree of saturation) and could become extremely long at a special chemical potential. Moreover, under the pinning effect, the substrate chemistry only determines the stability of the vapor bridges and the range of the capillary force, but has less influences on the magnitude of the capillary force, indicating that the substrate chemistry or the apparent contact angle for droplets or bubbles on the substrates is no longer a direct parameter to determine the magnitude of capillary force. A qualitative analysis for the two dimensional vapor bridges by considering the feedback mechanism can explain the results from the LDFT calculations.

Closed-loop wavelength stabilization of an optical parametric oscillator as a front end of a high-power iodine laser chain.

PubMed

Kral, L

2007-05-01

We present a complex stabilization and control system for a commercially available optical parametric oscillator. The system is able to stabilize the oscillator's output wavelength at a narrow spectral line of atomic iodine with subpicometer precision, allowing utilization of this solid-state parametric oscillator as a front end of a high-power photodissociation laser chain formed by iodine gas amplifiers. In such setup, a precise wavelength matching between the front end and the amplifier chain is necessary due to extremely narrow spectral lines of the gaseous iodine (approximately 20 pm). The system is based on a personal computer, a heated iodine cell, and a few other low-cost components. It automatically identifies the proper peak within the iodine absorption spectrum, and then keeps the oscillator tuned to this peak with high precision and reliability. The use of the solid-state oscillator as the front end allows us to use the whole iodine laser system as a pump laser for the optical parametric chirped pulse amplification, as it enables precise time synchronization with a signal Ti:sapphire laser.

Sensitivity, stability, and precision of quantitative Ns-LIBS-based fuel-air-ratio measurements for methane-air flames at 1-11 bar.

PubMed

Hsu, Paul S; Gragston, Mark; Wu, Yue; Zhang, Zhili; Patnaik, Anil K; Kiefer, Johannes; Roy, Sukesh; Gord, James R

2016-10-01

Nanosecond laser-induced breakdown spectroscopy (ns-LIBS) is employed for quantitative local fuel-air (F/A) ratio (i.e., ratio of actual fuel-to-oxidizer mass over ratio of fuel-to-oxidizer mass at stoichiometry, measurements in well-characterized methane-air flames at pressures of 1-11 bar). We selected nitrogen and hydrogen atomic-emission lines at 568 nm and 656 nm, respectively, to establish a correlation between the line intensities and the F/A ratio. We have investigated the effects of laser-pulse energy, camera gate delay, and pressure on the sensitivity, stability, and precision of the quantitative ns-LIBS F/A ratio measurements. We determined the optimal laser energy and camera gate delay for each pressure condition and found that measurement stability and precision are degraded with an increase in pressure. We have identified primary limitations of the F/A ratio measurement employing ns-LIBS at elevated pressures as instabilities caused by the higher density laser-induced plasma and the presence of the higher level of soot. Potential improvements are suggested.

Position-sensitive proportional counter with low-resistance metal-wire anode

DOEpatents

Kopp, Manfred K.

1980-01-01

A position-sensitive proportional counter circuit is provided which allows the use of a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counter. A pair of specially designed active-capacitance preamplifiers are used to terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, low-noise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates (>10.sup.6 counts/sec).

BEAM TRANSPORT LINES FOR THE BSNS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

WEI, J.

2006-06-26

This paper presents the design of two beam transport lines at the BSNS: one is the injection line from the Linac to the RCS and the other is the target line from the RCS to the target station. In the injection beam line, space charge effects, transverse halo collimation, momentum tail collimation and debunching are the main concerned topics. A new method of using triplet cells and stripping foils is used to collimate transverse halo. A long straight section is reserved for the future upgrading linac and debuncher. In the target beam line, large halo emittance, beam stability at themore » target due to kicker failures and beam jitters, shielding of back-scattering neutrons from the target are main concerned topics. Special bi-gap magnets will be used to reduce beam losses in the collimators in front of the target.« less

Sea-level feedback lowers projections of future Antarctic Ice-Sheet mass loss

PubMed Central

Gomez, Natalya; Pollard, David; Holland, David

2015-01-01

The stability of marine sectors of the Antarctic Ice Sheet (AIS) in a warming climate has been identified as the largest source of uncertainty in projections of future sea-level rise. Sea-level fall near the grounding line of a retreating marine ice sheet has a stabilizing influence on the ice sheets, and previous studies have established the importance of this feedback on ice age AIS evolution. Here we use a coupled ice sheet–sea-level model to investigate the impact of the feedback mechanism on future AIS retreat over centennial and millennial timescales for a range of emission scenarios. We show that the combination of bedrock uplift and sea-surface drop associated with ice-sheet retreat significantly reduces AIS mass loss relative to a simulation without these effects included. Sensitivity analyses show that the stabilization tends to be greatest for lower emission scenarios and Earth models characterized by a thin elastic lithosphere and low-viscosity upper mantle, as is the case for West Antarctica. PMID:26554381

Data analysis of photon beam position at PLS-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ko, J.; Shin, S., E-mail: tlssh@postech.ac.kr; Huang, Jung-Yun

In the third generation light source, photon beam position stability is critical issue on user experiment. Generally photon beam position monitors have been developed for the detection of the real photon beam position and the position is controlled by feedback system in order to keep the reference photon beam position. In the PLS-II, photon beam position stability for front end of particular beam line, in which photon beam position monitor is installed, has been obtained less than rms 1μm for user service period. Nevertheless, detail analysis for photon beam position data in order to demonstrate the performance of photon beammore » position monitor is necessary, since it can be suffers from various unknown noises. (for instance, a back ground contamination due to upstream or downstream dipole radiation, undulator gap dependence, etc.) In this paper, we will describe the start to end study for photon beam position stability and the Singular Value Decomposition (SVD) analysis to demonstrate the reliability on photon beam position data.« less

[Influence of autoclave sterilization on dimensional stability and detail reproduction of 5 additional silicone impression materials].

PubMed

Xu, Tong-kai; Sun, Zhi-hui; Jiang, Yong

2012-03-01

To evaluate the dimensional stability and detail reproduction of five additional silicone impression materials after autoclave sterilization. Impressions were made on the ISO 4823 standard mold containing several marking lines, in five kinds of additional silicone. All the impressions were sterilized by high temperature and pressure (135 °C, 212.8 kPa) for 25 min. Linear measurements of pre-sterilization and post-sterilization were made with a measuring microscope. Statistical analysis utilized single-factor analysis with pair-wise comparison of mean values when appropriate. Hypothesis testing was conducted at alpha = 0.05. No significant difference was found between the pre-sterilization and post-sterilization conditions for all locations, and all the absolute valuse of linear rate of change less than 8%. All the sterilization by the autoclave did not affect the surfuce detail reproduction of the 5 impression materials. The dimensional stability and detail reproduction of the five additional silicone impression materials in the study was unaffected by autoclave sterilization.

Low-order black-box models for control system design in large power systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamwa, I.; Trudel, G.; Gerin-Lajoie, L.

1996-02-01

The paper studies two multi-input multi-output (MIMO) procedures for the identification of low-order state-space models of power systems, by probing the network in open loop with low-energy pulses or random signals. Although such data may result from actual measurements, the development assumes simulated responses from a transient stability program, hence benefiting from the existing large base of stability models. While pulse data is processed using the eigensystem realization algorithm, the analysis of random responses is done by means of subspace identification methods. On a prototype Hydro-Quebec power system, including SVCs, DC lines, series compensation, and more than 1,100 buses, itmore » is verified that the two approaches are equivalent only when strict requirements are imposed on the pulse length and magnitude. The 10th-order equivalent models derived by random-signal probing allow for effective tuning of decentralized power system stabilizers (PSSs) able to damp both local and very slow inter-area modes.« less

Low-order black-box models for control system design in large power systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamwa, I.; Trudel, G.; Gerin-Lajoie, L.

1995-12-31

The paper studies two multi-input multi-output (MIMO) procedures for the identification of low-order state-space models of power systems, by probing the network in open loop with low-energy pulses or random signals. Although such data may result from actual measurements, the development assumes simulated responses from a transient stability program, hence benefiting form the existing large base of stability models. While pulse data is processed using the eigensystem realization algorithm, the analysis of random responses is done by means of subspace identification methods. On a prototype Hydro-Quebec power system, including SVCs, DC lines, series compensation, and more than 1,100 buses, itmore » is verified that the two approaches are equivalent only when strict requirements are imposed on the pulse length and magnitude. The 10th-order equivalent models derived by random-signal probing allow for effective tuning of decentralized power system stabilizers (PSSs) able to damp both local and very slow inter-area modes.« less

USP17 is upregulated in osteosarcoma and promotes cell proliferation, metastasis, and epithelial-mesenchymal transition through stabilizing SMAD4.

PubMed

Song, Chenyang; Liu, Wenge; Li, Jiandong

2017-07-01

USP17 is upregulated in several cancers, indicating that USP17 might play essential functions in tumor development. However, the function of USP17 in osteosarcoma is still unknown. Our work aimed to investigate the function of USP17 in osteosarcoma. We found that the expression of USP17 was upregulated in osteosarcoma tissues and cell lines, including MG-63 and U2OS. Several functional experiments, such as colony formation analysis, Cell Counting Kit-8 assay, wound healing analysis, and transwell assay, showed that USP17 promoted cell proliferation, migration, and invasion. Moreover, we found that USP17 facilitated migration and invasion through promoting epithelial-mesenchymal transition. SMAD4 has been found to regulate epithelial-mesenchymal transition, co-immunopurification, and glutathione S-transferase pull-down analysis demonstrated that USP17 interacted with SMAD4. Furthermore, USP17 stabilized SMAD4 through its deubiquitinase activity. In conclusion, this study shows that USP17 enhances osteosarcoma cell proliferation and invasion through stabilizing SMAD4.

Nonlinear stability and control of gliding vehicles

NASA Astrophysics Data System (ADS)

Bhatta, Pradeep

In this thesis we use nonlinear systems analysis to study dynamics and design control solutions for vehicles subject to hydrodynamic or aerodynamic forcing. Application of energy-based methods for such vehicles is challenging due to the presence of energy-conserving lift and side forces. We study how the lift force determines the geometric structure of vehicle dynamics. A Hamiltonian formulation of the integrable phugoid-mode equations provides a Lyapunov function candidate, which is used throughout the thesis for deriving equilibrium stability results and designing stabilizing control laws. A strong motivation for our work is the emergence of underwater gliders as an important observation platform for oceanography. Underwater gliders rely on buoyancy regulation and internal mass redistribution for motion control. These vehicles are attractive because they are designed to operate autonomously and continuously for several weeks. The results presented in this thesis contribute toward the development of systematic control design procedures for extending the range of provably stable maneuvers of the underwater glider. As the first major contribution we derive conditions for nonlinear stability of longitudinal steady gliding motions using singular perturbation theory. Stability is proved using a composite Lyapunov function, composed of individual Lyapunov functions that prove stability of rotational and translational subsystem equilibria. We use the composite Lyapunov function to design control laws for stabilizing desired relative equilibria in different actuation configurations for the underwater glider. We propose an approximate trajectory tracking method for an aircraft model. Our method uses exponential stability results of controllable steady gliding motions, derived by interpreting the aircraft dynamics as an interconnected system of rotational and translational subsystems. We prove bounded position error for tracking prescribed, straight-line trajectories, and demonstrate good performance in tracking unsteady trajectories in the longitudinal plane. We present all possible relative equilibrium motions for a rigid body moving in a fluid. Motion along a circular helix is a practical relative equilibrium for an underwater glider. We present a study of how internal mass distribution and buoyancy of the underwater glider influence the size of the steady circular helix, and the effect of a vehicle bottom-heaviness parameter on its stability.

The doctrinal basis for medical stability operations.

PubMed

Baker, Jay B

2010-01-01

This article describes possible roles for the military in the health sector during stability operations, which exist primarily when security conditions do not permit the free movement of civilian actors. This article reviews the new U.S. Army Field Manuals (FMs) 3-24, Counterinsurgency and FM 3-07, Stability Operations, in the context of the health sector. Essential tasks in medical stability operations are identified for various logical lines of operation including information operations, civil security, civil control, support to governance, support to economic development, and restoration of essential services. Restoring essential services is addressed in detail including coordination, assessment, actions, and metrics in the health sector. Coordination by the military with other actors in the health sector including host nation medical officials, other United States governmental agencies, international governmental organizations (IGOs), and nongovernment organizations (NGOs) is key to success in medical stability operations.

Precision axial translator with high stability.

PubMed

Bösch, M A

1979-08-01

We describe a new type of translator which is inherently stable against torsion and twisting. This concentric translator is also ideally suited for precise axial motion with clearance of the center line.

OSCILLATING FILAMENTS. I. OSCILLATION AND GEOMETRICAL FRAGMENTATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gritschneder, Matthias; Heigl, Stefan; Burkert, Andreas, E-mail: gritschm@usm.uni-muenchen.de

2017-01-10

We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid-based AMR code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, such as with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation, and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process “geometrical fragmentation.” In our realization, the spacing between the cores matches the wavelength of the sinusoidalmore » perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristic scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. We show that the overall oscillation pattern can hide the infall signature of cores.« less

A Scaled Framework for CRISPR Editing of Human Pluripotent Stem Cells to Study Psychiatric Disease.

PubMed

Hazelbaker, Dane Z; Beccard, Amanda; Bara, Anne M; Dabkowski, Nicole; Messana, Angelica; Mazzucato, Patrizia; Lam, Daisy; Manning, Danielle; Eggan, Kevin; Barrett, Lindy E

2017-10-10

Scaling of CRISPR-Cas9 technology in human pluripotent stem cells (hPSCs) represents an important step for modeling complex disease and developing drug screens in human cells. However, variables affecting the scaling efficiency of gene editing in hPSCs remain poorly understood. Here, we report a standardized CRISPR-Cas9 approach, with robust benchmarking at each step, to successfully target and genotype a set of psychiatric disease-implicated genes in hPSCs and provide a resource of edited hPSC lines for six of these genes. We found that transcriptional state and nucleosome positioning around targeted loci was not correlated with editing efficiency. However, editing frequencies varied between different hPSC lines and correlated with genomic stability, underscoring the need for careful cell line selection and unbiased assessments of genomic integrity. Together, our step-by-step quantification and in-depth analyses provide an experimental roadmap for scaling Cas9-mediated editing in hPSCs to study psychiatric disease, with broader applicability for other polygenic diseases. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Indomethacin derivatives as tubulin stabilizers to inhibit cancer cell proliferation.

PubMed

Chennamaneni, Snigdha; Gan, Chunfang; Lama, Rati; Zhong, Bo; Su, Bin

2016-01-15

Cyclooxygenase (COX) inhibitor Indomethacin analogs exhibited more potent cancer cell growth inhibition and apoptosis inducing activities than the parental compound. The anti-proliferative mechanism investigation of the analogs revealed that they inhibited tubulin polymerization at high concentrations whereas enhanced polymerization at low concentrations. The two opposite activities might antagonize each other and impaired the anti-proliferative activity of the derivatives eventually. In this study, we further performed lead optimization based on the structure activity relationship (SAR) generated. One of the new Indomethacin derivatives compound 11 {2-(4-(benzyloxy)phenyl)-N-(1-(4-bromobenzoyl)-3-(2-((2-(dimethylamino)ethyl)amino)-2-oxoethyl)-2-methyl-1H-indol-5-yl)acetamide} inhibited the proliferation of a panel of cancer cell lines with IC50s at the sub-micromole levels. Further study revealed that the compound only enhanced tubulin polymerization and was a tubulin stabilizer. Published by Elsevier Ltd.

Effect of vertical-tail location on the aerodynamic characteristics at subsonic speeds of a close-coupled canard configuration

NASA Technical Reports Server (NTRS)

Huffman, J. K.

1975-01-01

The effects were studied of various vertical-tail configurations on the longitudinal and lateral directional-stability characteristics of a general research fighter model utilizing wing-body-canard. The study indicates that the addition of the high canard resulted in an increase in total lift at angles of attack above 4 deg with a maximum lift coefficient about twice as large as that for the wing-body configuration. For the wing-body (canard off) configuration, the center-line vertical tail indicates positive vertical-tail effectiveness throughout the test angle-of-attack range; however, for this configuration none of the wing-mounted vertical-tail locations tested resulted in a positive directional-stability increment at the higher angles of attack. For the wing-body-canard configuration several outboard locations of the wing-mounted vertical tails were found.

Fluorescent Labeling and Biodistribution of Latex Nanoparticles Formed by Surfactant-Free RAFT Emulsion Polymerization.

PubMed

Poon, Cheuk Ka; Tang, Owen; Chen, Xin-Ming; Kim, Byung; Hartlieb, Matthias; Pollock, Carol A; Hawkett, Brian S; Perrier, Sébastien

2017-10-01

The authors report the preparation of a novel range of functional polyacrylamide stabilized polystyrene nanoparticles, obtained by surfactant-free reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization, their fluorescent tagging, cellular uptake, and biodistribution. The authors show the versatility of the RAFT emulsion process for the design of functional nanoparticles of well-defined size that can be used as drug delivery vectors. Functionalization with a fluorescent tag offers a useful visualization tool for tracing, localization, and clearance studies of these carriers in biological models. The studies are carried out by labeling the sterically stabilized latex particles chemically with rhodamine B. The fluorescent particles are incubated in a healthy human renal proximal tubular cell line model, and intravenously injected into a mouse model. Cellular localization and biodistribution of these particles on the biological models are explored. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of a Three-Channel High-Temperature Superconducting Magnetometer System

DTIC Science & Technology

1997-06-01

achieved by the best commercially available fluxgate magnetometers demonstrated to date and is only surpassed by low temperature superconducting...wire lines carry the analog SQUID magnetometer signal as well as dc power and ground, and the fiberoptic lines carry digital clock and data signals...with the magnetometers mounted on the three-sensor probe used in the sensor evaluated here. This probe is not highly stabilized with respect to the

On the nonlinear stability of mKdV breathers

NASA Astrophysics Data System (ADS)

Alejo, Miguel A.; Muñoz, Claudio

2012-11-01

Breather modes of the mKdV equation on the real line are known to be elastic under collisions with other breathers and solitons. This fact indicates very strong stability properties of breathers. In this communication we describe a rigorous, mathematical proof of the stability of breathers under a class of small perturbations. Our proof involves the existence of a nonlinear equation satisfied by all breather profiles, and a new Lyapunov functional which controls the dynamics of small perturbations and instability modes. In order to construct such a functional, we work in a subspace of the energy one. However, our proof introduces new ideas in order to attack the corresponding stability problem in the energy space. Some remarks about the sine-Gordon case are also considered.

Hairy black hole stability in AdS, quantum mechanics on the half-line and holography

NASA Astrophysics Data System (ADS)

Anabalón, Andrés; Astefanesei, Dumitru; Oliva, Julio

2015-10-01

We consider the linear stability of 4-dimensional hairy black holes with mixed boundary conditions in Anti-de Sitter spacetime. We focus on the mass of scalar fields around the maximally supersymmetric vacuum of the gauged N=8 supergravity in four dimensions, m 2 = -2 l -2. It is shown that the Schrödinger operator on the half-line, governing the S 2, H 2 or {{R}}^2 invariant mode around the hairy black hole, allows for non-trivial self-adjoint extensions and each of them corresponds to a class of mixed boundary conditions in the gravitational theory. Discarding the self-adjoint extensions with a negative mode impose a restriction on these boundary conditions. The restriction is given in terms of an integral of the potential in the Schrödinger operator resembling the estimate of Simon for Schrödinger operators on the real line. In the context of AdS/CFT duality, our result has a natural interpretation in terms of the field theory dual effective potential.

In-line monitoring of (MR) fluid properties

NASA Astrophysics Data System (ADS)

Kordonski, William; Gorodkin, Sergei; Behlok, Ray

2015-05-01

Proper functionality of devices and processes based on (MR) fluids greatly depends, along with other factors, on stability of fluid characteristics such as concentration of magnetic particles and magnetic properties of the particles. The concentration of magnetic particles may change due to evaporation or leakage of carrier fluid, as well as particle sedimentation. Magnetic properties may change due to temperature, corrosion of particles or irreversible aggregation. In-line noninvasive monitoring of particle concentration and magnetic properties allows, in one way or another, compensation for the impact of destabilizing factors and provides system stable output. Two novel methods of in-line measurement of MR fluid magnetic permeability or magnetic particle concentration are considered in this presentation. The first one is based on the principle of mutual inductance and is intended for monitoring MR fluid flowing in pipes or channels. In the second one, permeability is measured by a flash-mount sensor which reacts on changes in the reluctance of the MR fluid layer adjacent to the wall. The use of the methods for stabilization of the material removal rate in high precision finishing process employing aqueous MR fluid is discussed.

Line defects in graphene: How doping affects the electronic and mechanical properties

NASA Astrophysics Data System (ADS)

Berger, Daniel; Ratsch, Christian

2016-06-01

Graphene and carbon nanotubes have extraordinary mechanical and electronic properties. Intrinsic line defects such as local nonhexagonal reconstructions or grain boundaries, however, significantly reduce the tensile strength, but feature exciting electronic properties. Here, we address the properties of line defects in graphene from first principles on the level of full-potential density-functional theory, and assess doping as one strategy to strengthen such materials. We carefully disentangle the global and local effect of doping by comparing results from the virtual crystal approximation with those from local substitution of chemical species, in order to gain a detailed understanding of the breaking and stabilization mechanisms. We find that doping primarily affects the occupation of the frontier orbitals. Occupation through n -type doping or local substitution with nitrogen increases the ultimate tensile strength significantly. In particular, it can stabilize the defects beyond the ultimate tensile strength of the pristine material. We therefore propose this as a key strategy to strengthen graphenic materials. Furthermore, we find that doping and/or applying external stress lead to tunable and technologically interesting metal/semiconductor transitions.

77 FR 21619 - Shipping Coordinating Committee; Notice of Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-10

... goods, solid cargoes and containers; Stability, load lines and fishing vessel safety; Bulk liquids and... safety assessment; Piracy and armed robbery against ships; General cargo ship safety; Implementation of...

Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yun; Huang, Chunning; Aleksandrov, Alexander V

2013-01-01

We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstrationmore » of particle beam profile diagnostics using fiber optic laser pulse transmission line.« less

Expression, Biochemistry, and Stabilization with Camel Antibodies of Membrane Proteins: Case Study of the Mouse 5-HT3 Receptor.

PubMed

Hassaïne, Ghérici; Deluz, Cédric; Grasso, Luigino; Wyss, Romain; Hovius, Ruud; Stahlberg, Henning; Tomizaki, Takashi; Desmyter, Aline; Moreau, Christophe; Peclinovska, Lucie; Minniberger, Sonja; Mebarki, Lamia; Li, Xiao-Dan; Vogel, Horst; Nury, Hugues

2017-01-01

There is growing interest in the use of mammalian protein expression systems, and in the use of antibody-derived chaperones, for structural studies. Here, we describe protocols ranging from the production of recombinant membrane proteins in stable inducible cell lines to biophysical characterization of purified membrane proteins in complex with llama antibody domains. These protocols were used to solve the structure of the mouse 5-HT3 serotonin receptor but are of broad applicability for crystallization or cryo-electron microscopy projects.

Protopine, a novel microtubule-stabilizing agent, causes mitotic arrest and apoptotic cell death in human hormone-refractory prostate cancer cell lines.

PubMed

Chen, Chun-Han; Liao, Cho-Hwa; Chang, Ya-Ling; Guh, Jih-Hwa; Pan, Shiow-Lin; Teng, Che-Ming

2012-02-01

In this study, we investigated the anticancer effect of protopine on human hormone-refractory prostate cancer (HRPC) cells. Protopine exhibited an anti-proliferative effect by induction of tubulin polymerization and mitotic arrest, which ultimately led to apoptotic cell death. The data suggest that protopine increased the activity of cyclin-dependent kinase 1 (Cdk1)/cyclin B1 complex and that contributed to cell apoptosis by modulating mitochondria-mediated signaling pathways, such as Bcl-2 phosphorylation and Mcl-1 down-regulation. In conclusion, the data suggest that protopine is a novel microtubule stabilizer with anticancer activity in HRPC cells through apoptotic pathway by modulating Cdk1 activity and Bcl-2 family of proteins. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Topological Vortex and Knotted Dissipative Optical 3D Solitons Generated by 2D Vortex Solitons

NASA Astrophysics Data System (ADS)

Veretenov, N. A.; Fedorov, S. V.; Rosanov, N. N.

2017-12-01

We predict a new class of three-dimensional (3D) topological dissipative optical one-component solitons in homogeneous laser media with fast saturable absorption. Their skeletons formed by vortex lines where the field vanishes are tangles, i.e., Nc knotted or unknotted, linked or unlinked closed lines and M unclosed lines that thread all the closed lines and end at the infinitely far soliton periphery. They are generated by embedding two-dimensional laser solitons or their complexes in 3D space after their rotation around an unclosed, infinite vortex line with topological charge M0 (Nc , M , and M0 are integers). With such structure propagation, the "hula-hoop" solitons form; their stability is confirmed numerically. For the solitons found, all vortex lines have unit topological charge: the number of closed lines Nc=1 and 2 (unknots, trefoils, and Solomon knots links); unclosed vortex lines are unknotted and unlinked, their number M =1 , 2, and 3.

Topological Vortex and Knotted Dissipative Optical 3D Solitons Generated by 2D Vortex Solitons.

PubMed

Veretenov, N A; Fedorov, S V; Rosanov, N N

2017-12-29

We predict a new class of three-dimensional (3D) topological dissipative optical one-component solitons in homogeneous laser media with fast saturable absorption. Their skeletons formed by vortex lines where the field vanishes are tangles, i.e., N_{c} knotted or unknotted, linked or unlinked closed lines and M unclosed lines that thread all the closed lines and end at the infinitely far soliton periphery. They are generated by embedding two-dimensional laser solitons or their complexes in 3D space after their rotation around an unclosed, infinite vortex line with topological charge M_{0} (N_{c}, M, and M_{0} are integers). With such structure propagation, the "hula-hoop" solitons form; their stability is confirmed numerically. For the solitons found, all vortex lines have unit topological charge: the number of closed lines N_{c}=1 and 2 (unknots, trefoils, and Solomon knots links); unclosed vortex lines are unknotted and unlinked, their number M=1, 2, and 3.

Structural stability and energetics of grain boundary triple junctions in face centered cubic materials

NASA Astrophysics Data System (ADS)

Adlakha, I.; Solanki, K. N.

2015-03-01

We present a systematic study to elucidate the role of triple junctions (TJs) and their constituent grain boundaries on the structural stability of nanocrystalline materials. Using atomistic simulations along with the nudge elastic band calculations, we explored the atomic structural and thermodynamic properties of TJs in three different fcc materials. We found that the magnitude of excess energy at a TJ was directly related to the atomic density of the metal. Further, the vacancy binding and migration energetics in the vicinity of the TJ were examined as they play a crucial role in the structural stability of NC materials. The resolved line tension which takes into account the stress buildup at the TJ was found to be a good measure in predicting the vacancy binding tendency near the TJ. The activation energy for vacancy migration along the TJ was directly correlated with the measured excess energy. Finally, we show that the resistance for vacancy diffusion increased for TJs with larger excess stored energy and the defect mobility at some TJs is slower than their constituent GBs. Hence, our results have general implications on the diffusional process in NC materials and provide new insight into stabilizing NC materials with tailored TJs.

Landslide Hazard Probability Derived from Inherent and Dynamic Determinants

NASA Astrophysics Data System (ADS)

Strauch, Ronda; Istanbulluoglu, Erkan

2016-04-01

Landslide hazard research has typically been conducted independently from hydroclimate research. We unify these two lines of research to provide regional scale landslide hazard information for risk assessments and resource management decision-making. Our approach combines an empirical inherent landslide probability with a numerical dynamic probability, generated by combining routed recharge from the Variable Infiltration Capacity (VIC) macro-scale land surface hydrologic model with a finer resolution probabilistic slope stability model run in a Monte Carlo simulation. Landslide hazard mapping is advanced by adjusting the dynamic model of stability with an empirically-based scalar representing the inherent stability of the landscape, creating a probabilistic quantitative measure of geohazard prediction at a 30-m resolution. Climatology, soil, and topography control the dynamic nature of hillslope stability and the empirical information further improves the discriminating ability of the integrated model. This work will aid resource management decision-making in current and future landscape and climatic conditions. The approach is applied as a case study in North Cascade National Park Complex, a rugged terrain with nearly 2,700 m (9,000 ft) of vertical relief, covering 2757 sq km (1064 sq mi) in northern Washington State, U.S.A.

N-terminal aliphatic residues dictate the structure, stability, assembly, and small molecule binding of the coiled-coil region of cartilage oligomeric matrix protein.

PubMed

Gunasekar, Susheel K; Asnani, Mukta; Limbad, Chandani; Haghpanah, Jennifer S; Hom, Wendy; Barra, Hanna; Nanda, Soumya; Lu, Min; Montclare, Jin Kim

2009-09-15

The coiled-coil domain of cartilage oligomeric matrix protein (COMPcc) assembles into a homopentamer that naturally recognizes the small molecule 1,25-dihydroxyvitamin D(3) (vit D). To identify the residues critical for the structure, stability, oligomerization, and binding to vit D as well as two other small molecules, all-trans-retinol (ATR) and curcumin (CCM), here we perform an alanine scanning mutagenesis study. Ten residues lining the hydrophobic pocket of COMPcc were mutated into alanine; of the mutated residues, the N-terminal aliphatic residues L37, L44, V47, and L51 are responsible for maintaining the structure and function. Furthermore, two polar residues, T40 and Q54, within the N-terminal region when converted into alanine improve the alpha-helical structure, stability, and self-assembly behavior. Helical stability, oligomerization, and binding appear to be linked in a manner in which mutations that abolish helical structure and assembly bind poorly to vit D, ATR, and CCM. These results provide not only insight into COMPcc and its functional role but also useful guidelines for the design of stable, pentameric coiled-coils capable of selectively storing and delivering various small molecules.

Highly Efficient Genome Editing via CRISPR/Cas9 to Create Clock Gene Knockout Cells.

PubMed

Korge, Sandra; Grudziecki, Astrid; Kramer, Achim

2015-10-01

Targeted genome editing using CRISPR/Cas9 is a relatively new, revolutionary technology allowing for efficient and directed alterations of the genome. It has been widely used for loss-of-function studies in animals and cell lines but has not yet been used to study circadian rhythms. Here, we describe the application of CRISPR/Cas9 genome editing for the generation of an F-box and leucine-rich repeat protein 3 (Fbxl3) knockout in a human cell line. Genomic alterations at the Fbxl3 locus occurred with very high efficiency (70%-100%) and specificity at both alleles, resulting in insertions and deletions that led to premature stop codons and hence FBXL3 knockout. Fbxl3 knockout cells displayed low amplitude and long period oscillations of Bmal1-luciferase reporter activity as well as increased CRY1 protein stability in line with previously published phenotypes for Fbxl3 knockout in mice. Thus, CRISPR/Cas9 genome editing should be highly valuable for studying circadian rhythms not only in human cells but also in classic model systems as well as nonmodel organisms. © 2015 The Author(s).

Clickable prodrugs bearing potent and hydrolytically cleavable nicotinamide phosphoribosyltransferase inhibitors.

PubMed

Sadrerafi, Keivan; Mason, Emilia O; Lee, Mark W

2018-01-01

Our previous study indicated that carborane containing small-molecule 1-(hydroxymethyl)-7-(4'-( trans -3″-(3'″-pyridyl)acrylamido)butyl)-1,7-dicarbadodecaborane (hm-MC4-PPEA), was a potent inhibitor of nicotinamide phosphoribosyltransferase (Nampt). Nampt has been shown to be upregulated in most cancers and is a promising target for the treatment of many different types of cancers, including breast cancers. To increase the selectivity of hm-MC4-PPEA toward cancer cells, three prodrugs were synthesized with different hydrolyzable linkers: ester, carbonate, and carbamate. Using click chemistry a fluorophore was attached to these prodrugs to act as a model for our conjugation strategy and to serve as an aid for prodrug stability studies. The stabilities of these drug conjugates were tested in phosphate-buffered saline (PBS) at normothermia (37°C) using three different pH levels, 5.5, 7.5, and 9.5, as well as in horse serum at physiological pH. The stability of each was monitored using reversed-phase HPLC equipped with both diode array and fluorescence detection. The inhibitory activity of hm-MC4-PPEA was also measured using a commercially available colorimetric assay. The biological activities of the drug conjugates as well as those of the free drug (hm-MC4-PPEA), were evaluated using the MTT assay against the human breast cancer cell lines T47D and MCF7, as well as the noncancerous, transformed, Nampt-dependent human breast epithelium cell line 184A1. hm-MC4-PPEA showed to be a potent inhibitor of recombinant Nampt activity, exhibiting an IC50 concentration of 6.8 nM. The prodrugs showed great stability towards hydrolytic degradation under neutral, mildly acidic and mildly basic conditions. The carbamate prodrug also showed to be stable in rat serum. However, the carbonate and the ester prodrug release at various rates in serum presumably owing to the presence of several different classes of esterase. The biological activities of the drug conjugates correlate with the stability of their cleavable linkers observed in serum. The targeted and selective delivery of potent Nampt inhibitors to cancer cells is a potentially new route for the treatment of many cancers. These prodrugs linked to small cancer-associated peptides may be optimum for their use as targetable Nampt inhibitors.

76 FR 64300 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-18

... Halibut and Sablefish IFQ Program provides economic stability for the commercial hook-and-line fishery... years of management as an open access fishery, while maintaining the social and economic character of...

Checking Contact Points for Curiosity Drill

NASA Image and Video Library

2013-06-05

This image demonstrates how engineers place the drill carried by NASA Mars rover Curiosity onto rock targets. They first set down the drill two stabilizing prongs near the target, as shown by the dashed line.

Tuning differentiation signals for efficient propagation and in vitro validation of rat embryonic stem cell cultures.

PubMed

Meek, Stephen; Sutherland, Linda; Burdon, Tom

2015-01-01

The rat is one of the most commonly used laboratory animals in biomedical research and the recent isolation of genuine pluripotent rat embryonic stem (ES) cell lines has provided new opportunities for applying contemporary genetic engineering techniques to the rat and enhancing the use of this rodent in scientific research. Technical refinements that improve the stability of the rat ES cell cultures will undoubtedly further strengthen and broaden the use of these stem cells in biomedical research. Here, we describe a relatively simple and robust protocol that supports the propagation of germ line competent rat ES cells, and outline how tuning stem cell signaling using small molecule inhibitors can be used to both stabilize self-renewal of rat ES cell cultures and aid evaluation of their differentiation potential in vitro.

Instability of the heliopause driven by charge exchange interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avinash, K.; Zank, G. P.; Dasgupta, B.

2014-08-20

The stability of the heliopause that separates the tenuous hot magnetized heliosheath plasma from the dense cool local interstellar magnetized plasma is examined using a fully general model that includes all the essential physical processes. Charge exchange coupling between plasma protons and primary interstellar neutral atoms provides an effective gravity that drives Rayleigh-Taylor (RT)-like instabilities. The velocity difference or shear between the heliosheath and interstellar flows, when coupled to energetic neutral atoms (ENAs), drives a Kelvin-Helmholtz (KH)-like instability on the heliopause. The shoulder region of the heliopause is unstable to a new instability that has characteristics of a mixed RT-KH-likemore » mode. The instabilities are not stabilized by typical values of the magnetic fields in the inner and outer heliosheath (OHS). ENAs play an essential role in driving the KH-like instability, which is fully stabilized in their absence by magnetic fields. The nonlinear phase of these instabilities is briefly discussed. We also discuss the possibility that RT-like or mixed KH-RT-like instabilities drag outer heliosheath/very local interstellar medium (OHS/VLISM) magnetic field lines into the inner heliosheath (IHS) with the VLISM flow, and the possibility that IHS and VLISM magnetic field lines experience reconnection. Such reconnection may (1) greatly enhance the mixing of plasmas across the heliopause and (2) provide open magnetic field lines that allow easy ingress of galactic cosmic rays into the heliosphere and corresponding easy loss of anomalous cosmic rays from the heliosphere.« less

[Lithium and anticonvulsants in the treatment of mania and in the prophylaxis of recurrences].

PubMed

Salvi, Virginio; Cat Berro, Alberto; Bechon, Elisa; Bogetto, Filippo; Maina, Giuseppe

2011-01-01

A mood stabilizer is an agent effective in treating both poles of the illness and at the same time being able to prevent both manic and depressive episodes in bipolar disorder. According to a broader definition, a mood stabilizer should be effective in decreasing the frequency or severity of any type of episode in bipolar disorder, without worsening the frequency or severity of episodes of opposite polarity. According to this, anticonvulsants and atypical antipsychotics can be considered as mood stabilizers. In this paper we review the use of lithium and other anticonvulsants that have proved effective in randomized controlled trials of the treatment of manic episodes and prevention of recurrences of bipolar disorder. Lithium and valproate are considered as first-line treatment options for acute mania while evidence regarding carbamazepine is insufficient to consider it as a first-line agent. Patients who fail to respond to first-line treatments may benefit from the adjunct of an atypical antipsychotic such as olanzapine, quetiapine, risperidone or aripiprazole. Lithium retains the strongest evidence of efficacy in the prophylaxis of manic episodes, lamotrigine in the prevention of depressive episodes. Valproate and carbamazepine have no indication for long-term treatment of bipolar disorder. Lithium can still be considered a gold standard in the treatment of manic episodes as well as in the prophylaxis of recurrences. Other anticonvulsants should be employed in particular situations, such as valproic acid in the treatment of mania and lamotrigine in the prevention of depressive recurrences.

Robust shrinking ellipsoid model predictive control for linear parameter varying system

PubMed Central

Yan, Yan

2017-01-01

In this paper, a new off-line model predictive control strategy is presented for a kind of linear parameter varying system with polytopic uncertainty. A nest of shrinking ellipsoids is constructed by solving linear matrix inequality. By splitting the objective function into two parts, the proposed strategy moves most computations off-line. The on-line computation is only calculating the current control to assure the system shrinking into the smaller ellipsoid. With the proposed formulation, the stability of the closed system is proved, followed with two numerical examples to demonstrate the proposed method’s effectiveness in the end. PMID:28575028

Effect of Wall Temperature on Roughness Induced Attachment-Line Transition

NASA Technical Reports Server (NTRS)

Dietz, Anthony; Coleman, Colin; Laub, Jim; Poll, D. I. A.; Nixon, David (Technical Monitor)

1999-01-01

An experiment on a cooled swept cylinder in a low-disturbance Mach 1.6 wind tunnel is described. The flow attachment line is disturbed by trip wires of varying size and the laminar/turbulent state of the downstream boundary layer is determined with a hot wire. The results demonstrate that although cooling the wall increases the stability of the boundary layer, it promotes roughness induced transition. Analysis of the data suggests that the attachment- line Reynolds number can account for the effect of wall cooling if the viscosity is evaluated at a particular reference temperature.

Jet outflow and open field line measurements on the C-2U advanced beam-driven field-reversed configuration plasma experiment.

PubMed

Sheftman, D; Gupta, D; Roche, T; Thompson, M C; Giammanco, F; Conti, F; Marsili, P; Moreno, C D

2016-11-01

Knowledge and control of the axial outflow of plasma particles and energy along open-magnetic-field lines are of crucial importance to the stability and longevity of the advanced beam-driven field-reversed configuration plasma. An overview of the diagnostic methods used to perform measurements on the open field line plasma on C-2U is presented, including passive Doppler impurity spectroscopy, microwave interferometry, and triple Langmuir probe measurements. Results of these measurements provide the jet ion temperature and axial velocity, electron density, and high frequency density fluctuations.

Jet outflow and open field line measurements on the C-2U advanced beam-driven field-reversed configuration plasma experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheftman, D., E-mail: dsheftman@trialphaenergy.com; Gupta, D.; Roche, T.

Knowledge and control of the axial outflow of plasma particles and energy along open-magnetic-field lines are of crucial importance to the stability and longevity of the advanced beam-driven field-reversed configuration plasma. An overview of the diagnostic methods used to perform measurements on the open field line plasma on C-2U is presented, including passive Doppler impurity spectroscopy, microwave interferometry, and triple Langmuir probe measurements. Results of these measurements provide the jet ion temperature and axial velocity, electron density, and high frequency density fluctuations.

Comparative anti-psoriatic efficacy studies of clobetasol loaded chitin nanogel and marketed cream.

PubMed

Panonnummal, Rajitha; Jayakumar, R; Sabitha, M

2017-01-01

In the present study chitin nanogel loaded with anti-psoriatic drug clobetasol was developed (CLCNG) for its topical delivery in psoriasis. CLCNG had the particle size of 132±14nm, with gel like consistency, stability in refrigerator, having higher drug release properties at acidic pH. CLCNG exhibited significant toxicity towards HaCaT and THP-1cell lines by MTT assay. The uptake of nanogel by HaCaT cell lines was confirmed by fluorescent microscopy. CLCNG at 0.35mg/ml exhibited significant anti-inflammatory activity with an average of 65% and 70% inhibition in COX and LOX activities expressed in THP-1 cells. In vitro skin permeation studies revealed the increased transdermal flux with fragmented stratum corneum and loosened epidermal layers in CLCNG treated samples, compared with control drug solution. The in vivo anti-psoriatic studies done on imiquimod model confirmed the potential benefits of the nanogel for the topical delivery of clobetasol in psoriasis. Copyright © 2016 Elsevier B.V. All rights reserved.

Posterior tibial slope as a risk factor for anterior cruciate ligament rupture in soccer players.

PubMed

Senişik, Seçkin; Ozgürbüz, Cengizhan; Ergün, Metin; Yüksel, Oğuz; Taskiran, Emin; Işlegen, Cetin; Ertat, Ahmet

2011-01-01

Anterior cruciate ligament (ACL) is the primary stabilizer of the knee. An impairment of any of the dynamic or static stability providing factors can lead to overload on the other factors and ultimately to deterioration of knee stability. This can result in anterior tibial translation and rupture of the ACL. The purpose of this study was to examine the influence of tibial slope on ACL injury risk on soccer players. A total of 64 elite soccer players and 45 sedentary controls were included in this longitudinal and controlled study. The angle between the tibial mid-diaphysis line and the line between the anterior and posterior edges of the medial tibial plateau was measured as the tibial slope via lateral radiographs. Individual player exposure, and injuries sustained by the participants were prospectively recorded. Eleven ACL injuries were documented during the study period. Tibial slope was not different between soccer players and sedentary controls. Tibial slope in the dominant and non-dominant legs was greater for the injured players compared to the uninjured players. The difference reached a significant level only for the dominant legs (p < 0.001). While the tibial slopes of the dominant and non-dominant legs were not different on uninjured players (p > 0.05), a higher tibial slope was observed in dominant legs of injured players (p < 0.05). Higher tibial slope on injured soccer players compared to the uninjured ones supports the idea that the tibial slope degree might be an important risk factor for ACL injury. Key pointsDominant legs' tibial slopes of the injured players were significantly higher compared to the uninjured players (p < 0.001).Higher tibial slope was determined in dominant legs compared to the non-dominant side, for the injured players (p = 0.042). Different tibial slope measures in dominant and non-dominant legs might be the result of different loading and/or adaptation patterns in soccer.

Stabilization of hyperforin dicyclohexylammonium salt with dissolved albumin and albumin nanoparticles for studying hyperforin effects on 2D cultivation of keratinocytes in vitro.

PubMed

Füller, J; Kellner, T; Gaid, M; Beerhues, L; Müller-Goymann, C C

2018-05-01

Due to the limited chemical stability of the natural hyperforin molecule, a more stable form of hyperforin, i.e., the hyperforin dicyclohexylammonium salt (HYP-DCHA) has been used for ex vivo and in vitro experiments in recent years, but its actual stability under typical cell culture conditions has never been studied before. In this contribution the stability of HYP-DCHA was examined under typical cell culture conditions. Different cell culture media with and without fetal calf serum (FCS) supplementation were studied with regard to further stabilization of HYP-DCHA determined with HPLC analysis. Furthermore, albumin nanoparticles were examined as a stabilizing carrier system for HYP-DCHA. In this context, the interaction between HYP-DCHA and albumin nanoparticles (ANP) was examined with regard to size and loading with HYP . The effects of HYP-DCHA either supplied in cell culture medium or loaded on ANP on viability and cytotoxicity were studied in vitro on HaCaT monolayers (human keratinocyte cell line). HYP-DCHA supplied in FCS-containing medium was recovered completely after 24h of incubation. However, a lack of FCS caused a total loss of HYP-DCHA after less than 24h incubation time. Supplying HYP-DCHA loaded on ANP in an FCS-free medium resulted in a recovery of about 60% after 24h incubation. HYP-DCHA supplied in medium along with FCS showed a slow dose-dependent decrease in viability of HaCaT cells without any cytotoxic effects (antiproliferative effect). Treatment with HYP-DCHA with a lack of FCS resulted in a significantly faster decrease in viability which was mainly due to cytotoxicity. The latter was true for HYP-DHCA-loaded ANP where increased cytotoxicity was observed despite the presence of FCS. The results show that the stability of the widely used HYP-DCHA is rather limited under cell culture conditions. Especially a lack of FCS leads to degradation and/or oxidation of HYP-DCHA probably causing an increased cytotoxicity. In contrast, FCS supplementation fairly stabilizes HYP-DCHA under cell culture conditions while albumin nanoparticles may serve the same stabilization purpose despite increasing cytotoxic effects onto the cells themselves. Copyright © 2017 Elsevier B.V. All rights reserved.

Linear Stability of Relativistic Space-Charge Flow in a Magnetically Insulated Transmission Line Oscillator

DTIC Science & Technology

1989-04-01

MILO Magnetica fy insulated transmission line Slow-wave structure Relativistic Brillouin flow Space-charge waves Slow electromagnetic waves (over) 19... resonant layer always see a decelerating axial electric field. Consequently, field energy increases at the expense of particle energy. 17 AFWL-TR-88-103...Ve). If ve is greater than the structure coupling velocity, a resonant layer of electrons will always be present, and oscillations will occur at any

Prosperity or Perdition: Do Lines of Operations Apply in Stability Operations?

DTIC Science & Technology

2003-01-01

explains and defines lines of operations in familiar linear terms, specifying geographic, interior, and exterior examples. It also proposes a new...groups loyal to the two parties extended the blood feud into the rural areas of Colombia. During this fifteen-year period, known as La Violencia (The...the later states of La Violencia , a disillusioned, largely rural, minority movement emerged to form “Peasant Republics” in the country-side not

Posterior Shoulder Instability

PubMed Central

Antosh, Ivan J.; Tokish, John M.; Owens, Brett D.

2016-01-01

Context: Posterior shoulder instability has become more frequently recognized and treated as a unique subset of shoulder instability, especially in the military. Posterior shoulder pathology may be more difficult to accurately diagnose than its anterior counterpart, and commonly, patients present with complaints of pain rather than instability. “Posterior instability” may encompass both dislocation and subluxation, and the most common presentation is recurrent posterior subluxation. Arthroscopic and open treatment techniques have improved as understanding of posterior shoulder instability has evolved. Evidence Acquisition: Electronic databases including PubMed and MEDLINE were queried for articles relating to posterior shoulder instability. Study Design: Clinical review. Level of Evidence: Level 4. Results: In low-demand patients, nonoperative treatment of posterior shoulder instability should be considered a first line of treatment and is typically successful. Conservative treatment, however, is commonly unsuccessful in active patients, such as military members. Those patients with persistent shoulder pain, instability, or functional limitations after a trial of conservative treatment may be considered surgical candidates. Arthroscopic posterior shoulder stabilization has demonstrated excellent clinical outcomes, high patient satisfaction, and low complication rates. Advanced techniques may be required in select cases to address bone loss, glenoid dysplasia, or revision. Conclusion: Posterior instability represents about 10% of shoulder instability and has become increasingly recognized and treated in military members. Nonoperative treatment is commonly unsuccessful in active patients, and surgical stabilization can be considered in patients who do not respond. Isolated posterior labral repairs constitute up to 24% of operatively treated labral repairs in a military population. Arthroscopic posterior stabilization is typically considered as first-line surgical treatment, while open techniques may be required in complex or revision settings. PMID:27697889

Development of an automated on-line electrochemical chlorite ion sensor.

PubMed

Myers, John N; Steinecker, William H; Sandlin, Zechariah D; Cox, James A; Gordon, Gilbert; Pacey, Gilbert E

2012-05-30

A sensor system for the automatic, in-line, determination of chlorite ion is reported. Electroanalytical measurements were performed in electrolyte-free liquids by using an electrochemical probe (EC), which enables in-line detection in high-resistance media such as disinfected water. Cyclic voltammetry scan rate studies suggest that the current arising from the oxidation of chlorite ion at an EC probe is mass-transfer limited. By coupling FIA with an EC probe amperometric cell, automated analysis was achieved. This sensor is intended to fulfill the daily monitoring requirements of the EPA DBP regulations for chlorite ion. Detection limits of 0.02-0.13 mg/L were attained, which is about one order of magnitude below the MRDL. The sensor showed no faradaic signal for perchlorate, chlorate, or nitrate. The lifetime and stability of the sensor were investigated by measuring calibration curves over time under constant-flow conditions. Detection limits of <0.1 mg/L were repeatedly achieved over a period of three weeks. Copyright © 2012 Elsevier B.V. All rights reserved.

“Development of an Automated On-line Electrochemical Chlorite Ion Sensor”

PubMed Central

Myers, John N.; Steinecker, William H.; Sandlin, Zechariah D.; Cox, James A.; Gordon, Gilbert; Pacey, Gilbert E.

2012-01-01

A sensor system for the automatic, in-line, determination of chlorite ion is reported. Electroanalytical measurements were performed in electrolyte-free liquids by using an electrochemical probe (EC), which enables in-line detection in high-resistance media such as disinfected water. Cyclic voltammetry scan rate studies suggest that the current arising from the oxidation of chlorite ion at an EC probe is mass-transfer limited. By coupling FIA with an EC probe amperometric cell, automated analysis was achieved. This sensor is intended to fulfill the daily monitoring requirements of the EPA DBP regulations for chlorite ion. Detection limits of 0.02-0.13 mg/L were attained, which is about one order of magnitude below the MRDL. The sensor showed no faradaic signal for perchlorate, chlorate, or nitrate. The lifetime and stability of the sensor were investigated by measuring calibration curves over time under constant-flow conditions. Detection limits of <0.1 mg/L were repeatedly achieved over a period of three weeks. PMID:22608440

Theoretical analysis of exponential transversal method of lines for the diffusion equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salazar, A.; Raydan, M.; Campo, A.

1996-12-31

Recently a new approximate technique to solve the diffusion equation was proposed by Campo and Salazar. This new method is inspired on the Method of Lines (MOL) with some insight coming from the method of separation of variables. The proposed method, the Exponential Transversal Method of Lines (ETMOL), utilizes an exponential variation to improve accuracy in the evaluation of the time derivative. Campo and Salazar have implemented this method in a wide range of heat/mass transfer applications and have obtained surprisingly good numerical results. In this paper, the authors study the theoretical properties of ETMOL in depth. In particular, consistency,more » stability and convergence are established in the framework of the heat/mass diffusion equation. In most practical applications the method presents a very reduced truncation error in time and its different versions are proven to be unconditionally stable in the Fourier sense. Convergence of the solutions is then established. The theory is corroborated by several analytical/numerical experiments.« less

Influence of stellar radiation pressure on flow structure in the envelope of hot-Jupiter HD 209458b

NASA Astrophysics Data System (ADS)

Cherenkov, A. A.; Bisikalo, D. V.; Kosovichev, A. G.

2018-03-01

Close-in exoplanets are subjected to extreme radiation of their host stars. Photometric observations of the hot-Jupiter HD 209458b transit by HST/STIS detected strong absorption in the Ly α line, thus indicating the existence of a hydrogen envelope extending beyond the Roche lobe. The gasdynamic modelling (Bisikalo et al.) showed that the stable structure of this envelope is maintained by the balance between the Roche lobe overfilling and stellar wind pressure. Obviously, the dynamics and stability of the envelope can be affected by stellar radiation pressure. Using 3D gasdynamic simulations, we study the impact of radiation pressure in the Ly α line on the envelope of hot-Jupiter HD 209458b, and show that the effect is not strong enough to significantly affect the gasdynamics in the system. For a detectable radiation pressure effect the intensity of the Ly α line has to be by two orders of magnitude greater.

Freezing lines of colloidal Yukawa spheres. II. Local structure and characteristic lengths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gapinski, Jacek, E-mail: gapinski@amu.edu.pl; Patkowski, Adam; NanoBioMedical Center, A. Mickiewicz University, Umultowska 85, 61-614 Poznań

Using the Rogers-Young (RY) integral equation scheme for the static pair correlation functions combined with the liquid-phase Hansen-Verlet freezing rule, we study the generic behavior of the radial distribution function and static structure factor of monodisperse charge-stabilized suspensions with Yukawa-type repulsive particle interactions at freezing. In a related article, labeled Paper I [J. Gapinski, G. Nägele, and A. Patkowski, J. Chem. Phys. 136, 024507 (2012)], this hybrid method was used to determine two-parameter freezing lines for experimentally controllable parameters, characteristic of suspensions of charged silica spheres in dimethylformamide. A universal scaling of the RY radial distribution function maximum is shownmore » to apply to the liquid-bcc and liquid-fcc segments of the universal freezing line. A thorough analysis is made of the behavior of characteristic distances and wavenumbers, next-neighbor particle coordination numbers, osmotic compressibility factor, and the Ravaché-Mountain-Streett minimum-maximum radial distribution function ratio.« less

Persistent tangled vortex rings in generic excitable media.

PubMed

Winfree, A T

1994-09-15

Excitable media are exemplified by a range of living systems, such as mammalian heart muscle and its cells and Xenopus eggs. They also occur in non-living systems such as the autocatalytic Belousov-Zhabotinsky reaction. In most of these systems, activity patterns, such as concentration waves, typically radiate as spiral waves from a vortex of excitation created by some nonuniform stimulus. In three-dimensional systems, the vortex is commonly a line, and these vortex lines can form linked and knotted rings which contract into compact, particle-like bundles. In most previous work these stable 'organizing centres' have been found to be symmetrical and can be classified topologically. Here I show through numerical studies of a generic excitable medium that the more general configuration of vortex lines is a turbulent tangle, which is robust against changes in the parameters of the system or perturbations to it. In view of their stability, I suggest that these turbulent tangles should be observable in any of the many known excitable media.

Inheritance and effectiveness of two transgenes determining PVY resistance in progeny from crossing independently transformed tobacco lines.

PubMed

Czubacka, Anna; Sacco, Ermanno; Olszak-Przybyś, Hanna; Doroszewska, Teresa

2017-05-01

Genetic transformation of plants allows us to obtain improved genotypes enriched with the desired traits. However, if transgenic lines were to be used in breeding programs the stability of inserted transgenes is essential. In the present study, we followed the inheritance of transgenes in hybrids originated from crossing two transgenic tobacco lines resistant to Potato virus Y (PVY): MN 944 LMV with the transgene containing Lettuce mosaic virus coat protein gene (LMV CP) and AC Gayed ROKY2 with PVY replicase gene (ROKY2). Progeny populations generated by successive self-pollination were analyzed with respect to the transgene segregation ratio and resistance to Potato virus Y in tests carried out under greenhouse conditions. The presence of the virus in inoculated plants was detected by DAS-ELISA method. The results demonstrated the Mendelian fashion of inheritance of transgenes which were segregated independently and stably. As a result, we obtained T 4 generation of hybrid with both transgenes stacked and which was highly resistant to PVY.

Mid-infrared laser phase-locking to a remote near-infrared frequency reference for high-precision molecular spectroscopy

NASA Astrophysics Data System (ADS)

Chanteau, B.; Lopez, O.; Zhang, W.; Nicolodi, D.; Argence, B.; Auguste, F.; Abgrall, M.; Chardonnet, C.; Santarelli, G.; Darquié, B.; Le Coq, Y.; Amy-Klein, A.

2013-07-01

We present a method for accurate mid-infrared frequency measurements and stabilization to a near-infrared ultra-stable frequency reference, transmitted with a long-distance fibre link and continuously monitored against state-of-the-art atomic fountain clocks. As a first application, we measure the frequency of an OsO4 rovibrational molecular line around 10 μm with an uncertainty of 8 × 10-13. We also demonstrate the frequency stabilization of a mid-infrared laser with fractional stability better than 4 × 10-14 at 1 s averaging time and a linewidth below 17 Hz. This new stabilization scheme gives us the ability to transfer frequency stability in the range of 10-15 or even better, currently accessible in the near infrared or in the visible, to mid-infrared lasers in a wide frequency range.

Fracture propagation and stability of ice shelves governed by ice shelf heterogeneity

NASA Astrophysics Data System (ADS)

Borstad, Chris; McGrath, Daniel; Pope, Allen

2017-05-01

Tabular iceberg calving and ice shelf retreat occurs after full-thickness fractures, known as rifts, propagate across an ice shelf. A quickly evolving rift signals a threat to the stability of Larsen C, the Antarctic Peninsula's largest ice shelf. Here we reveal the influence of ice shelf heterogeneity on the growth of this rift, with implications that challenge existing notions of ice shelf stability. Most of the rift extension has occurred in bursts after overcoming the resistance of suture zones that bind together neighboring glacier inflows. We model the stresses in the ice shelf to determine potential rift trajectories. Calving perturbations to ice flow will likely reach the grounding line. The stability of Larsen C may hinge on a single suture zone that stabilizes numerous upstream rifts. Elevated fracture toughness of suture zones may be the most important property that allows ice shelves to modulate Antarctica's contribution to sea level rise.

Antitumor Activity of Lankacidin Group Antibiotics Is Due to Microtubule Stabilization via a Paclitaxel-like Mechanism.

PubMed

Ayoub, Ahmed Taha; Abou El-Magd, Rabab M; Xiao, Jack; Lewis, Cody Wayne; Tilli, Tatiana Martins; Arakawa, Kenji; Nindita, Yosi; Chan, Gordon; Sun, Luxin; Glover, Mark; Klobukowski, Mariusz; Tuszynski, Jack

2016-10-27

Lankacidin group antibiotics show strong antimicrobial activity against various Gram-positive bacteria. In addition, they were shown to have considerable antitumor activity against certain cell line models. For decades, the antitumor activity of lankacidin was associated with the mechanism of its antimicrobial action, which is interference with peptide bond formation during protein synthesis. This, however, was never confirmed experimentally. Due to significant similarity to paclitaxel-like hits in a previous computational virtual screening study, we suggested that the cytotoxic effect of lankacidin is due to a paclitaxel-like action. In this study, we tested this hypothesis computationally and experimentally and confirmed that lankacidin is a microtubule stabilizer that enhances tubulin assembly and displaces taxoids from their binding site. This study serves as a starting point for optimization of lankacidin derivatives for better antitumor activities. It also highlights the power of computational predictions and their aid in guiding experiments and formulating rigorous hypotheses.

Stability of fruit quality traits in diverse watermelon cultivars tested in multiple environments

PubMed Central

Dia, Mahendra; Wehner, Todd C; Perkins-Veazie, Penelope; Hassell, Richard; Price, Daniel S; Boyhan, George E; Olson, Stephen M; King, Stephen R; Davis, Angela R; Tolla, Gregory E; Bernier, Jerome; Juarez, Benito

2016-01-01

Lycopene is a naturally occurring red carotenoid compound that is found in watermelon. Lycopene has antioxidant properties. Lycopene content, sugar content and hollowheart resistance are subject to significant genotype×environment interaction (G×E), which makes breeding for these fruit quality traits difficult. The objectives of this study were to (i) evaluate the influence of years and locations on lycopene content, sugar content and hollowheart resistance for a set of watermelon genotypes, and (ii) identify genotypes with high stability for lycopene, sugar, and hollowheart resistance. A diverse set of 40 genotypes was tested over 3 years and 8 locations across the southern United States in replicated, multi-harvest trials. Lycopene was tested in a subset of 10 genotypes. Data were analyzed using univariate and multivariate stability statistics (BLUP-GGE biplot) using SASGxE and RGxE programs. There were strong effects of environment as well as G×E interaction on watermelon quality traits. On the basis of stability measures, genotypes were classified as stable or unstable for each quality trait. 'Crimson Sweet' is an inbred line with high quality trait performance as well as trait stability. 'Stone Mountain', 'Tom Watson', 'Crimson Sweet' and 'Minilee' were among the best genotypes for lycopene content, sugar content and hollowheart resistance. We developed a stability chart based on marketable yield and average ranking generated from different stability measures for yield attributes and quality traits. The chart will assist in choosing parents for improvement of watermelon cultivars. See http://cuke.hort.ncsu.edu/cucurbit/wmelon/wmelonmain.html. PMID:28066557

Design Concepts for Helicopter Pallets and Gondolas

DTIC Science & Technology

1974-11-01

Effectiveness 25 STABILITY 26 Towing Stability 26 Vertical Drag 31 CH-47 32 Table of Contents (continued) PAGE CH-54 35 Hm 36 Lift Point...enemy fire increases as the vehicle operates near the area or line of engagement. Therefore, it may be undesirable to expose the Hm (a high-value...i UPPER STRUCTURE LOADS &■ 30181 ^ S ^ ^ A" ^>- 1 9841 880 1408 ♦ 8 29018 9848 Figure 30. Gondola Loaded With M54 Truck and M149 Trailer

Two Observed Consequences of Penetration Electric Fields

DTIC Science & Technology

2008-10-11

satellites are three- axis stabilized spacecraft that fly in circular. Sun -synchronous, polar ( inclination 98.7 ) orbits at an altitude of ~840km. The...350 km. The orbital period was —10 h. CRRES was spin stabilized at a rate of 2 rpm. Its spin axis always pointed within 15 of the Sun . The line of...satellites with flight designations 10 and higher, orbital ascending nodes are on the dusk side of the Earth . Thus, during the Halloween storm DMSP

A note on the effects of viscosity on the stability of a trailing-line vortex

NASA Technical Reports Server (NTRS)

Duck, Peter W.; Khorrami, Mehdi R.

1992-01-01

The linear stability of the Batchelor (1964) vortex is examined with emphasis on new viscous modes recently found numerically by Khorrami (1991). Unlike the previously reported inviscid modes of instability, these modes are destabilized by viscosity and exhibit small growth rates at large Reynolds numbers. The analysis presented here uses a combination of asymptotic and numerical techniques. The results confirm the existence of the additional modes of instability due to viscosity.

Stream Channel Stability. Appendix A. Evaluation of Streambank Erosion Control Demonstration Projects in the Bluff Line Streams of Northwest Mississippi,

DTIC Science & Technology

1981-04-01

streambanks except on very small channels and agricultural waterways. Vegetation is commonly used to stabilize small agricultural storm runoff ...subjected to severe hydrologic and plant growth stresses during 1980. Large storm runoff events, occurring early in the year, produced velocities in...than average for the prevailing conditions. The overall survival rate for the 1979 and 1980 plantings of the shrub type bristly locus (Robinia fertilis

Terahertz Pulsed Imaging and Magnetic Resonance Imaging as Tools to Probe Formulation Stability

PubMed Central

Zhang, Qilei; Gladden, Lynn F.; Avalle, Paolo; Zeitler, J. Axel; Mantle, Michael D.

2013-01-01

Dissolution stability over the entire shelf life duration is of critical importance to ensure the quality of solid dosage forms. Changes in the drug release profile during storage may affect the bioavailability of drug products. This study investigated the stability of a commercial tablet (Lescol® XL) when stored under accelerated conditions (40 °C/75% r.h.). Terahertz pulsed imaging (TPI) was used to investigate the structure of the tablet coating before and after the accelerated aging process. The results indicate that the coating was reduced in thickness and exhibited a higher density after being stored under accelerated conditions for four weeks. In situ magnetic resonance imaging (MRI) of the water penetration processes during tablet dissolution in a USP-IV dissolution cell equipped with an in-line UV-vis analyzer was carried out to study local differences in water uptake into the tablet matrix between the stressed and unstressed state. The drug release profiles of the Lescol® XL tablet before and after the accelerated storage stability testing were compared using a “difference” factor f1 and a “similarity” factor f2. The results reveal that even though the physical properties of the coating layers changed significantly during the stress testing, the coating protected the tablet matrix and the densification of the coating polymer had no adverse effect on the drug release performance. PMID:24300564

Electrostatic interaction between dissimilar colloids at fluid interfaces

NASA Astrophysics Data System (ADS)

Majee, Arghya; Schmetzer, Timo; Bier, Markus

2018-04-01

The electrostatic interaction between two nonidentical, moderately charged colloids situated in close proximity of each other at a fluid interface is studied. By resorting to a well-justified model system, this problem is analytically solved within the framework of linearized Poisson-Boltzmann density functional theory. The resulting interaction comprises a surface and a line part, both of which, as functions of the interparticle separation, show a rich behavior including monotonic as well as nonmonotonic variations. In almost all cases, these variations cannot be captured correctly by using the superposition approximation. Moreover, expressions for the surface tensions, the line tensions and the fluid-fluid interfacial tension, which are all independent of the interparticle separation, are obtained. Our results are expected to be particularly useful for emulsions stabilized by oppositely charged particles.

Lipid cross-linking of nanolipoprotein particles substantially enhances serum stability and cellular uptake [Lipid crosslinking enhances the stability of nanolipoprotein particles in serum by multiple orders of magnitude

DOE PAGES

Gilmore, Sean F.; Blanchette, Craig D.; Scharadin, Tiffany M.; ...

2016-07-13

Nanolipoprotein particles (NLPs) consist of a discoidal phospholipid lipid bilayer confined by an apolipoprotein belt. NLPs are a promising platform for a variety of biomedical applications due to their biocompatibility, size, definable composition, and amphipathic characteristics. However, poor serum stability hampers the use of NLPs for in vivo applications such as drug formulation. In this study, NLP stability was enhanced upon the incorporation and subsequent UV-mediated intermolecular cross-linking of photoactive DiynePC phospholipids in the lipid bilayer, forming cross-linked nanoparticles (X-NLPs). Both the concentration of DiynePC in the bilayer and UV exposure time significantly affected the resulting X-NLP stability in 100%more » serum, as assessed by size exclusion chromatography (SEC) of fluorescently labeled particles. Cross-linking did not significantly impact the size of X-NLPs as determined by dynamic light scattering and SEC. X-NLPs had essentially no degradation over 48 h in 100% serum, which is a drastic improvement compared to non-cross-linked NLPs (50% degradation by ~10 min). X-NLPs had greater uptake into the human ATCC 5637 bladder cancer cell line compared to non-cross-linked particles, indicating their potential utility for targeted drug delivery. X-NLPs also exhibited enhanced stability following intravenous administration in mice. Lastly, these results collectively support the potential utility of X-NLPs for a variety of in vivo applications.« less

Lipid cross-linking of nanolipoprotein particles substantially enhances serum stability and cellular uptake [Lipid crosslinking enhances the stability of nanolipoprotein particles in serum by multiple orders of magnitude

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilmore, Sean F.; Blanchette, Craig D.; Scharadin, Tiffany M.

Nanolipoprotein particles (NLPs) consist of a discoidal phospholipid lipid bilayer confined by an apolipoprotein belt. NLPs are a promising platform for a variety of biomedical applications due to their biocompatibility, size, definable composition, and amphipathic characteristics. However, poor serum stability hampers the use of NLPs for in vivo applications such as drug formulation. In this study, NLP stability was enhanced upon the incorporation and subsequent UV-mediated intermolecular cross-linking of photoactive DiynePC phospholipids in the lipid bilayer, forming cross-linked nanoparticles (X-NLPs). Both the concentration of DiynePC in the bilayer and UV exposure time significantly affected the resulting X-NLP stability in 100%more » serum, as assessed by size exclusion chromatography (SEC) of fluorescently labeled particles. Cross-linking did not significantly impact the size of X-NLPs as determined by dynamic light scattering and SEC. X-NLPs had essentially no degradation over 48 h in 100% serum, which is a drastic improvement compared to non-cross-linked NLPs (50% degradation by ~10 min). X-NLPs had greater uptake into the human ATCC 5637 bladder cancer cell line compared to non-cross-linked particles, indicating their potential utility for targeted drug delivery. X-NLPs also exhibited enhanced stability following intravenous administration in mice. Lastly, these results collectively support the potential utility of X-NLPs for a variety of in vivo applications.« less

Spatial inhomogeneities in ionic liquids, charged proteins, and charge stabilized colloids from collective variables theory.

PubMed

Patsahan, O; Ciach, A

2012-09-01

Effects of size and charge asymmetry between oppositely charged ions or particles on spatial inhomogeneities are studied for a large range of charge and size ratios. We perform a stability analysis of the primitive model of ionic systems with respect to periodic ordering using the collective variables-based theory. We extend previous studies [Ciach et al., Phys. Rev. E 75, 051505 (2007)] in several ways. First, we employ a nonlocal approximation for the reference hard-sphere fluid which leads to the Percus-Yevick pair direct correlation functions for the uniform case. Second, we use the Weeks-Chandler-Anderson regularization scheme for the Coulomb potential inside the hard core. We determine the relevant order parameter connected with the periodic ordering and analyze the character of the dominant fluctuations along the λ lines. We show that the above-mentioned modifications produce large quantitative and partly qualitative changes in the phase diagrams obtained previously. We discuss possible scenarios of the periodic ordering for the whole range of size and charge ratios of the two ionic species, covering electrolytes, ionic liquids, charged globular proteins or nanoparticles in aqueous solutions, and charge-stabilized colloids.

Characterization and quenching of friction-induced limit cycles of electro-hydraulic servovalve control systems with transport delay.

PubMed

Wang, Yuan-Jay

2010-10-01

This paper develops a systematic and straightforward methodology to characterize and quench the friction-induced limit cycle conditions in electro-hydraulic servovalve control systems with transport delay in the transmission line. The nonlinear friction characteristic is linearized by using its corresponding describing function. The delay time in the transmission line, which could accelerate the generation of limit cycles is particularly considered. The stability equation method together with parameter plane method provides a useful tool for the establishment of necessary conditions to sustain a limit cycle directly in the constructed controller coefficient plane. Also, the stable region, the unstable region, and the limit cycle region are identified in the parameter plane. The parameter plane characterizes a clear relationship between limit cycle amplitude, frequency, transport delay, and the controller coefficients to be designed. The stability of the predicted limit cycle is checked by plotting stability curves. The stability of the system is examined when the viscous gain changes with respect to the temperature of the working fluid. A feasible stable region is characterized in the parameter plane to allow a flexible choice of controller gains. The robust prevention of limit cycle is achieved by selecting controller gains from the asymptotic stability region. The predicted results are verified by simulations. It is seen that the friction-induced limit cycles can be effectively predicted, removed, and quenched via the design of the compensator even in the case of viscous gain and delay time variations unconditionally. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Interferometric rotation sensor

NASA Technical Reports Server (NTRS)

Walsh, T. M.

1972-01-01

Sensor generates interference fringes varying in number (horizontally and vertically) as a function of the total angular deviation relative to the line-of-sight axis. Device eliminates errors from zero or null shift due to lack of electrical circuitry stability.

Does a conservative tibial cut in conventional total knee arthroplasty violate the deep medial collateral ligament?

PubMed

Maes, Michael; Luyckx, Thomas; Bellemans, Johan

2014-11-01

Based on the anatomy of the deep medial collateral ligament (MCL), it was hypothesized that at least part of its cross-sectional insertion area is jeopardized while performing a standard tibial cut in conventional total knee arthroplasty (TKA). The aim of this study was to determine whether it is anatomically possible to preserve the tibial deep MCL insertion during conventional TKA. Thirty-three unpaired cadaveric knee specimens were used for this study. Knees with severe varus/valgus deformity or damage to the medial structures of the knee were excluded. In the first part of the study, the dimensions of the tibial insertion of the deep MCL and its relationship to the joint line were recorded. Next, the cross-sectional area of the deep MCL insertion was determined using calibrated digital photographic analysis. In the second part, the effect of a standard 9-mm 3° sloped tibial cut on the structural integrity of the deep MCL cross-sectional insertion area was determined using conventional instrumentation. The proximal border of the deep MCL insertion site on the tibia was located on average 4.7 ± 1.2 mm distally to the joint line. After performing a standard 9-mm 3° sloped tibial cut, on average 54% of the deep MCL insertion area was resected. In 29% of the cases, the deep MCL insertion area was completely excised. The deep MCL cannot routinely be preserved in conventional TKA. The deep MCL insertion is at risk and may be jeopardized in case of a tibial cut 9 mm below the native joint line. As the deep MCL is a distinct medial stabilizer and plays an important role in rotational stability, this may have implications in future designs of both unicondylar and total knee arthroplasty, but further research is necessary.

Type I Interferon Controls Propagation of Long Interspersed Element-1*

PubMed Central

Yu, Qiujing; Carbone, Christopher J.; Katlinskaya, Yuliya V.; Zheng, Hui; Zheng, Ke; Luo, Mengcheng; Wang, P. Jeremy; Greenberg, Roger A.; Fuchs, Serge Y.

2015-01-01

Type I interferons (IFN) including IFNα and IFNβ are critical for the cellular defense against viruses. Here we report that increased levels of IFNβ were found in testes from mice deficient in MOV10L1, a germ cell-specific RNA helicase that plays a key role in limiting the propagation of retrotransposons including Long Interspersed Element-1 (LINE-1). Additional experiments revealed that activation of LINE-1 retrotransposons increases the expression of IFNβ and of IFN-stimulated genes. Conversely, pretreatment of cells with IFN suppressed the replication of LINE-1. Furthermore, the efficacy of LINE-1 replication was increased in isogenic cell lines harboring inactivating mutations in diverse elements of the IFN signaling pathway. Knockdown of the IFN receptor chain IFNAR1 also stimulated LINE-1 propagation in vitro. Finally, a greater accumulation of LINE-1 was found in mice that lack IFNAR1 compared with wild type mice. We propose that LINE-1-induced IFN plays an important role in restricting LINE-1 propagation and discuss the putative role of IFN in preserving the genome stability. PMID:25716322

Nuclear exoticism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penionzhkevich, Yu. E., E-mail: pyuer@mail.ru

2016-07-15

Extreme states of nuclearmatter (such that feature high spins, large deformations, high density and temperature, or a large excess of neutrons and protons) play an important role in studying fundamental properties of nuclei and are helpful in solving the problem of constructing the equation of state for nuclear matter. The synthesis of neutron-rich nuclei near the nucleon drip lines and investigation of their properties permit drawing conclusions about the positions of these boundaries and deducing information about unusual states of such nuclei and about their decays. At the present time, experimental investigations along these lines can only be performed viamore » the cooperation of leading research centers that possess powerful heavy-ion accelerators, such as the Large Hadron Collider (LHC) at CERN and the heavy-ion cyclotrons at the Joint Institute for Nuclear Research (JINR, Dubna), where respective experiments are being conducted by physicists from about 20 JINR member countries. The present article gives a survey of the most recent results in the realms of super neutron-rich nuclei. Implications of the change in the structure of such nuclei near the nucleon drip lines are discussed. Information about the results obtained by measuring the masses (binding energies) of exotic nuclei, the nucleon-distribution radii (neutron halo) and momentum distributions in them, and their deformations and quantum properties is presented. It is shown that the properties of nuclei lying near the stability boundaries differ strongly from the properties of other nuclei. The problem of the stability of nuclei that is associated with the magic numbers of 20 and 28 is discussed along with the effect of new magic numbers.« less

The Stress Protein BAG3 Stabilizes Mcl-1 Protein and Promotes Survival of Cancer Cells and Resistance to Antagonist ABT-737*

PubMed Central

Boiani, Mariana; Daniel, Cristina; Liu, Xueyuan; Hogarty, Michael D.; Marnett, Lawrence J.

2013-01-01

Members of the Bcl-2 family of proteins are important inhibitors of apoptosis in human cancer and are targets for novel anticancer agents such as the Bcl-2 antagonists, ABT-263 (Navitoclax), and its analog ABT-737. Unlike Bcl-2, Mcl-1 is not antagonized by ABT-263 or ABT-737 and is considered to be a major factor in resistance. Also, Mcl-1 exhibits differential regulation when compared with other Bcl-2 family members and is a target for anticancer drug discovery. Here, we demonstrate that BAG3, an Hsp70 co-chaperone, protects Mcl-1 from proteasomal degradation, thereby promoting its antiapoptotic activity. Using neuroblastoma cell lines, with a defined Bcl-2 family dependence, we found that BAG3 expression correlated with Mcl-1 dependence and ABT-737 resistance. RNA silencing of BAG3 led to a marked reduction in Mcl-1 protein levels and overcame ABT-737 resistance in Mcl-1-dependent cells. In ABT-737-resistant cells, Mcl-1 co-immunoprecipitated with BAG3, and loss of Mcl-1 after BAG3 silencing was prevented by proteasome inhibition. BAG3 and Mcl-1 were co-expressed in a panel of diverse cancer cell lines resistant to ABT-737. Silencing BAG3 reduced Mcl-1 protein levels and overcame ABT-737 resistance in several of the cell lines, including triple-negative breast cancer (MDA-MB231) and androgen receptor-negative prostate cancer (PC3) cells. These studies identify BAG3-mediated Mcl-1 stabilization as a potential target for cancer drug discovery. PMID:23341456

The stress protein BAG3 stabilizes Mcl-1 protein and promotes survival of cancer cells and resistance to antagonist ABT-737.

PubMed

Boiani, Mariana; Daniel, Cristina; Liu, Xueyuan; Hogarty, Michael D; Marnett, Lawrence J

2013-03-08

Members of the Bcl-2 family of proteins are important inhibitors of apoptosis in human cancer and are targets for novel anticancer agents such as the Bcl-2 antagonists, ABT-263 (Navitoclax), and its analog ABT-737. Unlike Bcl-2, Mcl-1 is not antagonized by ABT-263 or ABT-737 and is considered to be a major factor in resistance. Also, Mcl-1 exhibits differential regulation when compared with other Bcl-2 family members and is a target for anticancer drug discovery. Here, we demonstrate that BAG3, an Hsp70 co-chaperone, protects Mcl-1 from proteasomal degradation, thereby promoting its antiapoptotic activity. Using neuroblastoma cell lines, with a defined Bcl-2 family dependence, we found that BAG3 expression correlated with Mcl-1 dependence and ABT-737 resistance. RNA silencing of BAG3 led to a marked reduction in Mcl-1 protein levels and overcame ABT-737 resistance in Mcl-1-dependent cells. In ABT-737-resistant cells, Mcl-1 co-immunoprecipitated with BAG3, and loss of Mcl-1 after BAG3 silencing was prevented by proteasome inhibition. BAG3 and Mcl-1 were co-expressed in a panel of diverse cancer cell lines resistant to ABT-737. Silencing BAG3 reduced Mcl-1 protein levels and overcame ABT-737 resistance in several of the cell lines, including triple-negative breast cancer (MDA-MB231) and androgen receptor-negative prostate cancer (PC3) cells. These studies identify BAG3-mediated Mcl-1 stabilization as a potential target for cancer drug discovery.

Synthesis, characterization of 1,2,4-triazole Schiff base derived 3d-metal complexes: Induces cytotoxicity in HepG2, MCF-7 cell line, BSA binding fluorescence and DFT study

NASA Astrophysics Data System (ADS)

Tyagi, Prateek; Tyagi, Monika; Agrawal, Swati; Chandra, Sulekh; Ojha, Himanshu; Pathak, Mallika

2017-01-01

Two novel Schiff base ligands H2L1 and H2L2 have been synthesized by condensation reaction of amine derivative of 1,2,4-triazole moiety with 2-hydroxy-4-methoxybenzaldehyde. Co(II), Ni(II), Cu(II) and Zn(II) of the synthesized Schiff bases were prepared by using a molar ratio of ligand:metal as 1:1. The structure of the Schiff bases and synthesized metal complexes were established by 1H NMR, UV-Vis, IR, Mass spectrometry and molar conductivity. The thermal stability of the complexes was study by TGA. Fluorescence quenching mechanism of metal complexes 1-4 show that Zn(II) and Cu(II) complex binds more strongly to BSA. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31 + g(d,p) basis set. The spectral data shows that the ligands behaves as binegative tridentate. On the basis of the spectral studies, TGA and DFT data an octahedral geometry has been assigned for Co(II), Ni(II), square planar for Cu(II) and tetrahedral for Zn(II) complexes. The anticancer activity were screened against human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2). Result indicates that metal complexes shows increase cytotoxicity in proliferation to cell lines as compared to free ligand.

The Use of Transcription Terminators to Generate Transgenic Lines of Chinese Hamster Ovary Cells (CHO) with Stable and High Level of Reporter Gene Expression.

PubMed

Gasanov, N B; Toshchakov, S V; Georgiev, P G; Maksimenko, O G

2015-01-01

Mammalian cell lines are widely used to produce recombinant proteins. Stable transgenic cell lines usually contain many insertions of the expression vector in one genomic region. Transcription through transgene can be one of the reasons for target gene repression after prolonged cultivation of cell lines. In the present work, we used the known transcription terminators from the SV40 virus, as well as the human β- and γ-globin genes, to prevent transcription through transgene. The transcription terminators were shown to increase and stabilize the expression of the EGFP reporter gene in transgenic lines of Chinese hamster ovary (CHO) cells. Hence, transcription terminators can be used to create stable mammalian cells with a high and stable level of recombinant protein production.

Symmetry-Enforced Line Nodes in Unconventional Superconductors [Nodal-Line Superconductors and Band-Sticking

DOE PAGES

Micklitz, T.; Norman, M. R.

2017-05-18

We classify line nodes in superconductors with strong spin-orbit interactions and time-reversal symmetry, where the latter may include nonprimitive translations in the magnetic Brillouin zone to account for coexistence with antiferromagnetic order. We find four possible combinations of irreducible representations of the order parameter on high-symmetry planes, two of which allow for line nodes in pseudospin-triplet pairs and two that exclude conventional fully gapped pseudospin-singlet pairs. We show that the former can only be realized in the presence of band-sticking degeneracies, and we verify their topological stability using arguments based on Clifford algebra extensions. Lastly, our classification exhausts all possiblemore » symmetry protected line nodes in the presence of spin-orbit coupling and a (generalized) time-reversal symmetry. Implications for existing nonsymmorphic and antiferromagnetic superconductors are discussed.« less

The stability analysis of magnetohydrodynamic equilibria - Comparing the thermodynamic approach with the energy principle

NASA Technical Reports Server (NTRS)

Brinkmann, R. P.

1989-01-01

This paper is a contribution to the stability analysis of current-carrying plasmas, i.e., plasma systems that are forced by external mchanisms to carry a nonrelaxing electrical current. Under restriction to translationally invariant configurations, the thermodynamic stability criterion for a multicomponent plasma is rederived within the framework of nonideal MHD. The chosen dynamics neglects scalar resistivity, but allows for other types of dissipation effects both in Ohm's law and in the equation of motion. In the second section of the paper, the thermodynamic stability criterion is compared with the ideal MHD based energy principle of Bernstein et al. With the help of Schwarz's inequality, it is shown that the former criterion is always more 'pessimistic' than the latter, i.e., that thermodynamic stability implies stability according to the MHD principle, but not vice versa. This reuslt confirms the physical plausible idea that dissipational effects tend to weaken the stability properties of current-carrying plasma equilibria by breaking the constraints of ideal MHD and allowing for possibly destabilizing effects such as magnetic field line reconfiguration.

Low-cost wireless voltage & current grid monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hines, Jacqueline

This report describes the development and demonstration of a novel low-cost wireless power distribution line monitoring system. This system measures voltage, current, and relative phase on power lines of up to 35 kV-class. The line units operate without any batteries, and without harvesting energy from the power line. Thus, data on grid condition is provided even in outage conditions, when line current is zero. This enhances worker safety by detecting the presence of voltage and current that may appear from stray sources on nominally isolated lines. Availability of low-cost power line monitoring systems will enable widespread monitoring of the distributionmore » grid. Real-time data on local grid operating conditions will enable grid operators to optimize grid operation, implement grid automation, and understand the impact of solar and other distributed sources on grid stability. The latter will enable utilities to implement eneygy storage and control systems to enable greater penetration of solar into the grid.« less

Spacecraft Line-of-Sight Stabilization Using LWIR Earth Signature

NASA Technical Reports Server (NTRS)

Quadrelli, Marco B.; Piazzolla, Sabino

2012-01-01

The objective of this study is to investigate the potential of using the bright and near-uniform Earth infrared (or wavelength infrared, LWIR) signature as a stable reference for accurate (micro-rad or less) inertial pointing and tracking on-board an space vehicle, including the determination of the fundamental limits of applicability of the proposed method for space missions. We demonstrate sub-micro radian level pointing accuracy under a representative set of disturbances experienced by the spacecraft in orbit.

Study of the Power Supply Ripple Effect on teh Dynamics at SPEAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terebilo, A.; Pellegrini, C.; /UCLA

For long term stability analysis time variation of tunes is important. We have proposed and tested a technique for measuring the magnitude of this variation. This was made possible by using tune extraction algorithms that require small number of turns thus giving an instantaneous tune of the machine. In this paper we demonstrate the measured effect of the tune modulation with 60 Hz power supplies ripple, power line interference from SLAC linac operating at 30 Hz repetition rate, and nonperiodic variation.

Dynamics of human categorization in a collaborative tagging system: How social processes of semantic stabilization shape individual sensemaking.

PubMed

Ley, Tobias; Seitlinger, Paul

2015-10-01

We study how categories form and develop over time in a sensemaking task by groups of students employing a collaborative tagging system. In line with distributed cognition theories, we look at both the tags students use and their strength of representation in memory. We hypothesize that categories get more differentiated over time as students learn, and that semantic stabilization on the group level (i.e. the convergence in the use of tags) mediates this relationship. Results of a field experiment that tested the impact of topic study duration on the specificity of tags confirms these hypotheses, although it was not study duration that produced this effect, but rather the effectiveness of the collaborative taxonomy the groups built. In the groups with higher levels of semantic stabilization, we found use of more specific tags and better representation in memory. We discuss these findings with regard to the important role of the information value of tags that would drive both the convergence on the group level as well as a shift to more specific levels of categorization. We also discuss the implication for cognitive science research by highlighting the importance of collaboratively built artefacts in the process of how knowledge is acquired, and implications for educational applications of collaborative tagging environments.

Dynamics of human categorization in a collaborative tagging system: How social processes of semantic stabilization shape individual sensemaking

PubMed Central

Ley, Tobias; Seitlinger, Paul

2015-01-01

We study how categories form and develop over time in a sensemaking task by groups of students employing a collaborative tagging system. In line with distributed cognition theories, we look at both the tags students use and their strength of representation in memory. We hypothesize that categories get more differentiated over time as students learn, and that semantic stabilization on the group level (i.e. the convergence in the use of tags) mediates this relationship. Results of a field experiment that tested the impact of topic study duration on the specificity of tags confirms these hypotheses, although it was not study duration that produced this effect, but rather the effectiveness of the collaborative taxonomy the groups built. In the groups with higher levels of semantic stabilization, we found use of more specific tags and better representation in memory. We discuss these findings with regard to the important role of the information value of tags that would drive both the convergence on the group level as well as a shift to more specific levels of categorization. We also discuss the implication for cognitive science research by highlighting the importance of collaboratively built artefacts in the process of how knowledge is acquired, and implications for educational applications of collaborative tagging environments. PMID:26566299

Considerations for opto-mechanical vs. digital stabilization in surveillance systems

NASA Astrophysics Data System (ADS)

Kowal, David

2015-05-01

Electro-optical surveillance and reconnaissance systems are frequently mounted on unstable or vibrating platforms such as ships, vehicles, aircraft and masts. Mechanical coupling between the platform and the cameras leads to angular vibration of the line of sight. Image motion during detector and eye integration times leads to image smear and a resulting loss of resolution. Additional effects are wavy images for detectors based on a rolling shutter mechanism and annoying movement of the image at low frequencies. A good stabilization system should yield sub-pixel stabilization errors and meet cost and size requirements. There are two main families of LOS stabilization methods: opto-mechanical stabilization and electronic stabilization. Each family, or a combination of both, can be implemented by a number of different techniques of varying complexity, size and cost leading to different levels of stabilization. Opto-mechanical stabilization is typically based on gyro readings, whereas electronic stabilization is typically based on gyro readings or image registration calculations. A few common stabilization techniques, as well as options for different gimbal arrangements will be described and analyzed. The relative merits and drawbacks of the different techniques and their applicability to specific systems and environments will be discussed. Over the years Controp has developed a large number of stabilized electro-optical payloads. A few examples of payloads with unique stabilization mechanisms will be described.

Fast detection of tobacco mosaic virus infected tobacco using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Peng, Jiyu; Song, Kunlin; Zhu, Hongyan; Kong, Wenwen; Liu, Fei; Shen, Tingting; He, Yong

2017-03-01

Tobacco mosaic virus (TMV) is one of the most devastating viruses to crops, which can cause severe production loss and affect the quality of products. In this study, we have proposed a novel approach to discriminate TMV-infected tobacco based on laser-induced breakdown spectroscopy (LIBS). Two different kinds of tobacco samples (fresh leaves and dried leaf pellets) were collected for spectral acquisition, and partial least squared discrimination analysis (PLS-DA) was used to establish classification models based on full spectrum and observed emission lines. The influences of moisture content on spectral profile, signal stability and plasma parameters (temperature and electron density) were also analysed. The results revealed that moisture content in fresh tobacco leaves would worsen the stability of analysis, and have a detrimental effect on the classification results. Good classification results were achieved based on the data from both full spectrum and observed emission lines of dried leaves, approaching 97.2% and 88.9% in the prediction set, respectively. In addition, support vector machine (SVM) could improve the classification results and eliminate influences of moisture content. The preliminary results indicate that LIBS coupled with chemometrics could provide a fast, efficient and low-cost approach for TMV-infected disease detection in tobacco leaves.

Fast detection of tobacco mosaic virus infected tobacco using laser-induced breakdown spectroscopy

PubMed Central

Peng, Jiyu; Song, Kunlin; Zhu, Hongyan; Kong, Wenwen; Liu, Fei; Shen, Tingting; He, Yong

2017-01-01

Tobacco mosaic virus (TMV) is one of the most devastating viruses to crops, which can cause severe production loss and affect the quality of products. In this study, we have proposed a novel approach to discriminate TMV-infected tobacco based on laser-induced breakdown spectroscopy (LIBS). Two different kinds of tobacco samples (fresh leaves and dried leaf pellets) were collected for spectral acquisition, and partial least squared discrimination analysis (PLS-DA) was used to establish classification models based on full spectrum and observed emission lines. The influences of moisture content on spectral profile, signal stability and plasma parameters (temperature and electron density) were also analysed. The results revealed that moisture content in fresh tobacco leaves would worsen the stability of analysis, and have a detrimental effect on the classification results. Good classification results were achieved based on the data from both full spectrum and observed emission lines of dried leaves, approaching 97.2% and 88.9% in the prediction set, respectively. In addition, support vector machine (SVM) could improve the classification results and eliminate influences of moisture content. The preliminary results indicate that LIBS coupled with chemometrics could provide a fast, efficient and low-cost approach for TMV-infected disease detection in tobacco leaves. PMID:28300144

Ultrafast dynamics and stabilization in chip-scale optical frequency combs (Conference Presentation)

NASA Astrophysics Data System (ADS)

Huang, Shu Wei

2017-02-01

Optical frequency comb technology has been the cornerstone for scientific breakthroughs such as precision frequency metrology, re-definition of time, extreme light-matter interaction, and attosecond sciences. Recently emerged Kerr-active microresonators are promising alternatives to the current benchmark femtosecond laser platform. These chip-scale frequency combs, or Kerr combs, are unique in their compact footprints and offer the potential for monolithic electronic and feedback integration, thereby expanding the already remarkable applications of optical frequency combs. In this talk, I will first report the generation and characterization of low-phase-noise Kerr frequency combs. Measurements of the Kerr comb ultrafast dynamics and phase noise will be presented and discussed. Then I will describe novel strategies to fully stabilize Kerr comb line frequencies towards chip-scale optical frequency synthesizers with a relative uncertainty better than 2.7×10-16. I will show that the unique generation physics of Kerr frequency comb can provide an intrinsic self-referenced access to the Kerr comb line frequencies. The strategy improves the optical frequency stability by more than two orders of magnitude, while preserving the Kerr comb's key advantage of low SWaP and potential for chip-scale electronic and photonic integration.

Hyperfine structure of excited states and quadrupole moment of Ne-21 using laser-induced line-narrowing techniques.

NASA Technical Reports Server (NTRS)

Ducas, T. W.; Feld, M. S.; Ryan, L. W., Jr.; Skribanowitz, N.; Javan, A.

1972-01-01

Observation results are presented on the optical hyperfine structure in Ne-21 obtained with the aid of laser-induced line-narrowing techniques. The output from a long stabilized single-mode 1.15-micron He-Ne laser focused into an external sample cell containing Ne-21 was used in implementing these techniques. Their applicability is demonstrated for optical hyperfine structure observation in systems whose features are ordinarily masked by Doppler broadening.

76 FR 23993 - Proposed Information Collection; Comment Request; Alaska Individual Fishing Quotas (IFQs) for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

... provides economic stability for the commercial hook-and-line fishery while reducing many of the... access fishery, while maintaining the social and economic character of the fixed gear fishery that is...

Systematic gene tagging using CRISPR/Cas9 in human stem cells to illuminate cell organization

PubMed Central

Roberts, Brock; Haupt, Amanda; Tucker, Andrew; Grancharova, Tanya; Arakaki, Joy; Fuqua, Margaret A.; Nelson, Angelique; Hookway, Caroline; Ludmann, Susan A.; Mueller, Irina A.; Yang, Ruian; Horwitz, Rick; Rafelski, Susanne M.; Gunawardane, Ruwanthi N.

2017-01-01

We present a CRISPR/Cas9 genome-editing strategy to systematically tag endogenous proteins with fluorescent tags in human induced pluripotent stem cells (hiPSC). To date, we have generated multiple hiPSC lines with monoallelic green fluorescent protein tags labeling 10 proteins representing major cellular structures. The tagged proteins include alpha tubulin, beta actin, desmoplakin, fibrillarin, nuclear lamin B1, nonmuscle myosin heavy chain IIB, paxillin, Sec61 beta, tight junction protein ZO1, and Tom20. Our genome-editing methodology using Cas9/crRNA ribonuclear protein and donor plasmid coelectroporation, followed by fluorescence-based enrichment of edited cells, typically resulted in <0.1–4% homology-directed repair (HDR). Twenty-five percent of clones generated from each edited population were precisely edited. Furthermore, 92% (36/39) of expanded clonal lines displayed robust morphology, genomic stability, expression and localization of the tagged protein to the appropriate subcellular structure, pluripotency-marker expression, and multilineage differentiation. It is our conclusion that, if cell lines are confirmed to harbor an appropriate gene edit, pluripotency, differentiation potential, and genomic stability are typically maintained during the clonal line–generation process. The data described here reveal general trends that emerged from this systematic gene-tagging approach. Final clonal lines corresponding to each of the 10 cellular structures are now available to the research community. PMID:28814507

The EVE Doppler Sensitivity and Flare Observations

NASA Technical Reports Server (NTRS)

Hudson, H. S.; Woods, T. N.; Chamberlin, P. C.; Didkovsky, L.; Del Zanna, G.

2011-01-01

The Extreme-ultraviolet Variability Experiment (EVE) obtains continuous EUV spectra of the Sun viewed as a star. Its primary objective is the characterization of solar spectral irradiance, but its sensitivity and stability make it extremely interesting for observations of variability on time scales down to the limit imposed by its basic 10 s sample interval. In this paper we characterize the Doppler sensitivity of the EVE data. We find that the 30.4 nm line of He II has a random Doppler error below 0.001 nm (1 pm, better than 10 km/s as a redshift), with ample stability to detect the orbital motion of its satellite, the Solar Dynamics Observatory (SDO). Solar flares also displace the spectrum, both because of Doppler shifts and because of EVE's optical layout, which (as with a slitless spectrograph) confuses position and wavelength. As a flare develops, the centroid of the line displays variations that reflect Doppler shifts and therefore flare dynamics. For the impulsive phase of the flare SOL2010-06-12, we find the line centroid to have a redshift of 16.8 +/- 5.9 km/s relative to that of the flare gradual phase (statistical errors only). We find also that high-temperature lines, such as Fe XXIV 19.2 nm, have well-determined Doppler components for major flares, with decreasing apparent blueshifts as expected from chromospheric evaporation flows.

Body-centered orthorhombic C 16 : A novel topological node-line semimetal

DOE PAGES

Wang, Jian -Tao; Weng, Hongming; Nie, Simin; ...

2016-05-11

We identify by ab initio calculations a novel topological semimetal carbon phase in all-sp 2 bonding networks with a 16-atom body-centered orthorhombic unit cell, termed bco-C 16. Total-energy calculations show that bco-C 16 is comparable to solid fcc-C 60 in energetic stability, and phonon and molecular dynamics simulations confirm its dynamical stability. This all-sp 2 carbon allotrope can be regarded as a three-dimensional modification of graphite, and its simulated x-ray diffraction (XRD) pattern matches well a previously unexplained diffraction peak in measured XRD spectra of detonation and chimney soot, indicating its presence in the specimen. Electronic band structure calculations revealmore » that bco-C 16 is a topological node-line semimetal with a single nodal ring. Lastly, these findings establish a novel carbon phase with intriguing structural and electronic properties of fundamental significance and practical interest.« less

Automatic Implementation of Prony Analysis for Electromechanical Mode Identification from Phasor Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Ning; Huang, Zhenyu; Tuffner, Francis K.

2010-07-31

Small signal stability problems are one of the major threats to grid stability and reliability. Prony analysis has been successfully applied on ringdown data to monitor electromechanical modes of a power system using phasor measurement unit (PMU) data. To facilitate an on-line application of mode estimation, this paper developed a recursive algorithm for implementing Prony analysis and proposed an oscillation detection method to detect ringdown data in real time. By automatically detect ringdown data, the proposed method helps guarantee that Prony analysis is applied properly and timely on the ringdown data. Thus, the mode estimation results can be performed reliablymore » and timely. The proposed method is tested using Monte Carlo simulations based on a 17-machine model and is shown to be able to properly identify the oscillation data for on-line application of Prony analysis.« less

Efficient laser noise reduction method via actively stabilized optical delay line.

PubMed

Li, Dawei; Qian, Cheng; Li, Ye; Zhao, Jianye

2017-04-17

We report a fiber laser noise reduction method by locking it to an actively stabilized optical delay line, specifically a fiber-based Mach-Zehnder interferometer with a 10 km optical fiber spool. The fiber spool is used to achieve large arm imbalance. The heterodyne signal of the two arms converts the laser noise from the optical domain to several megahertz, and it is used in laser noise reduction by a phase-locked loop. An additional phase-locked loop is induced in the system to compensate the phase noise due to environmentally induced length fluctuations of the optical fiber spool. A major advantage of this structure is the efficient reduction of out-of-loop frequency noise, particularly at low Fourier frequency. The frequency noise reaches -30 dBc/Hz at 1 Hz, which is reduced by more than 90 dB compared with that of the laser in its free-running state.

Regional Curves for Bankfull Channel Characteristics in the Appalachian Plateaus, West Virginia

USGS Publications Warehouse

Messinger, Terence

2009-01-01

Streams in the Appalachian Plateaus Physiographic Province in West Virginia were classified as a single region on the basis of bankfull characteristics. Regression lines for annual peak flow and drainage area measured at streamgages in the study area at recurrence intervals between 1.2 and 1.7 years fell within the 99-percent confidence interval of the regression line for bankfull flow. Channel characteristics were intermediate among those from surrounding states and regions where comparable studies have been done. The stream reaches that were surveyed were selected for apparent stability, and to represent gradients of drainage area, elevation, and mean annual precipitation. Profiles of high-water marks left by bankfull and near-bankfull peaks were surveyed, either as part of slope-area flow measurements at ungaged reaches, or to transfer known flow information to cross sections for gaged reaches. The slope-area measurements made it possible to include ungaged sites in the study, but still relate bankfull dimensions to peak flow and frequency.