Response of porous beryllium to static and dynamic loading

Energy Technology Data Exchange (ETDEWEB)

Isbell, W.M.; Walton, O.R.; Ree, F.H.

1977-07-01

Previous investigstions of the mechanical response of porous materials to dynamic loading have been extended to include the shock wave response of a brittle metal. The complex response of berylliums of 85 to 90 percent porosity in two initial conditions has been examined in a theoretical and experimental program to be described. The study has resulted in the development of constitutive relations placed in hydrocodes which are capable of accurately predicting wave propagation in the berylliums. A comprehensive set of static (0 to 4 Gpa) and dynamic (0 to 35 Gpa) experiments was performed to measure the behavior of these brittle, porous materials to imposed loads. The results of the experiments guided a modeling effort which added several new features to previous models, including deviatoric stresses, porosity-dependent relaxation time of pore closure, elastic-plastic reopening of pores, and improved compaction functions.

Response of porous beryllium to static and dynamic loading

International Nuclear Information System (INIS)

Isbell, W.M.; Walton, O.R.; Ree, F.H.

1977-07-01

Previous investigstions of the mechanical response of porous materials to dynamic loading have been extended to include the shock wave response of a brittle metal. The complex response of berylliums of 85 to 90 percent porosity in two initial conditions has been examined in a theoretical and experimental program to be described. The study has resulted in the development of constitutive relations placed in hydrocodes which are capable of accurately predicting wave propagation in the berylliums. A comprehensive set of static (0 to 4 Gpa) and dynamic (0 to 35 Gpa) experiments was performed to measure the behavior of these brittle, porous materials to imposed loads. The results of the experiments guided a modeling effort which added several new features to previous models, including deviatoric stresses, porosity-dependent relaxation time of pore closure, elastic-plastic reopening of pores, and improved compaction functions

Static high-gradient magnetic fields affect the functionality of monocytic cells

Czech Academy of Sciences Publication Activity Database

Syrovets, T.; Schmidt, Z.; Buechele, B.; Zablotskyy, Vitaliy A.; Dejneka, Alexandr; Dempsey, N.; Simmet, T.

2014-01-01

Roč. 28, č. 1 (2014), s. 1-2 ISSN 0892-6638 Institutional support: RVO:68378271 Keywords : static high-gradient * magnet ic fields * affect the functionality * monocytic cells Subject RIV: BM - Solid Matter Physics ; Magnet ism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.)

Antioxidant capacity of parsley cells (Petroselinum crispum L.) in relation to iron-induced ferritin levels and static magnetic field.

Science.gov (United States)

Rajabbeigi, Elham; Ghanati, Faezeh; Abdolmaleki, Parviz; Payez, Atefeh

2013-12-01

This study was aimed to evaluate antioxidant response of parsley cells to 21 ppm iron and static magnetic field (SMF; 30 mT). The activity of catalase (CAT) and ascorbate peroxidase (APX) and the contents of malonyldialdehyde, iron and ferritin were measured at 6 and 12 h after treatments. Exposure to SMF increased the activity of CAT in treated cells, while combination of iron and SMF treatments as well as iron supply alone decreased CAT activity, compared to that of control cells. Combination of SMF with iron treatment reduced iron content of the cells and ameliorated mal effect of iron on CAT activity. All treatments reduced APX activity; however, the content of total ascorbate increased in response to iron and SMF+iron. The results showed that among the components of antioxidant system of parsley cells, enhanced activity of CAT in SMF-treated cells and increase of ascorbate in SMF+Fe-treated ones were responsible for the maintenance of membranes integrity. Ferritin contents of SMF- and SMF+Fe-treated cells also decreased significantly 12 h after treatments, compared to those of the control cells. These results cast doubt on the proposed functions of ferritin as a putative reactive oxygen species detoxifying molecule.

Mathematical modeling of the lithium, thionyl chloride static cell. I. Neutral electrolyte. II - Acid electrolyte

Energy Technology Data Exchange (ETDEWEB)

Tsaur, K.C.; Pollard, R.

1984-05-01

Mathematical models are presented for a Li-LiAlCl4/SOCl2-C static cell with neutral electrolyte and a Li/SOCl2-C static cell with acid electrolyte. The model for the Li-LiAlCl4/SOCl2-C cell with neutral solution predicts that high internal resistance can develop in the positive electrode as a result of low local porosities which are, in turn, caused by large-volume, solid reaction products. Consequently, the maximum usable cell capacity is dictated by the nonuniformity of the reaction distribution at the front of the positive electrode. In many respects, a cell with acid electrolyte can be regarded as a combination of an equivalent neutral electrolyte system and an acid reservoir. The model for the Li/SOCl2 cell suggests that the cell life depends primarily on the quantity of acid added to the electrolyte. 58 references.

Mathematical modeling of the lithium, thionyl chloride static cell. I - Neutral electrolyte. II - Acid electrolyte

Science.gov (United States)

Tsaur, K.-C.; Pollard, R.

1984-05-01

Mathematical models are presented for a Li-LiAlCl4/SOCl2-C static cell with neutral electrolyte and a Li/SOCl2-C static cell with acid electrolyte. The model for the Li-LiAlCl4/SOCl2-C cell with neutral solution predicts that high internal resistance can develop in the positive electrode as a result of low local porosities which are, in turn, caused by large-volume, solid reaction products. Consequently, the maximum usable cell capacity is dictated by the nonuniformity of the reaction distribution at the front of the positive electrode. In many respects, a cell with acid electrolyte can be regarded as a combination of an equivalent neutral electrolyte system and an acid reservoir. The model for the Li/SOCl2 cell suggests that the cell life depends primarily on the quantity of acid added to the electrolyte.

Static and dynamic light scattering by red blood cells: A numerical study.

Science.gov (United States)

Mauer, Johannes; Peltomäki, Matti; Poblete, Simón; Gompper, Gerhard; Fedosov, Dmitry A

2017-01-01

Light scattering is a well-established experimental technique, which gains more and more popularity in the biological field because it offers the means for non-invasive imaging and detection. However, the interpretation of light-scattering signals remains challenging due to the complexity of most biological systems. Here, we investigate static and dynamic scattering properties of red blood cells (RBCs) using two mesoscopic hydrodynamics simulation methods-multi-particle collision dynamics and dissipative particle dynamics. Light scattering is studied for various membrane shear elasticities, bending rigidities, and RBC shapes (e.g., biconcave and stomatocyte). Simulation results from the two simulation methods show good agreement, and demonstrate that the static light scattering of a diffusing RBC is not very sensitive to the changes in membrane properties and moderate alterations in cell shapes. We also compute dynamic light scattering of a diffusing RBC, from which dynamic properties of RBCs such as diffusion coefficients can be accessed. In contrast to static light scattering, the dynamic measurements can be employed to differentiate between the biconcave and stomatocytic RBC shapes and generally allow the differentiation based on the membrane properties. Our simulation results can be used for better understanding of light scattering by RBCs and the development of new non-invasive methods for blood-flow monitoring.

Static contribution of the higher modes in the dynamic response of structures

International Nuclear Information System (INIS)

Barbosa, H.J.C.

1982-03-01

In the dynamic response of structures by the modal superposition method usually only the lower modes are taken into account and a procedure that could estimate the contribution due to the higher modes without calculating them would be useful. The technique which consists of assuming that the higher modes respond statically is discussed here. Structures subjected to support motion which are analysed by response spectra techniques are considered and some numerical results are presented. (Author) [pt

Effect of initial strain and material nonlinearity on the nonlinear static and dynamic response of graphene sheets

Science.gov (United States)

Singh, Sandeep; Patel, B. P.

2018-06-01

Computationally efficient multiscale modelling based on Cauchy-Born rule in conjunction with finite element method is employed to study static and dynamic characteristics of graphene sheets, with/without considering initial strain, involving Green-Lagrange geometric and material nonlinearities. The strain energy density function at continuum level is established by coupling the deformation at continuum level to that at atomic level through Cauchy-Born rule. The atomic interactions between carbon atoms are modelled through Tersoff-Brenner potential. The governing equation of motion obtained using Hamilton's principle is solved through standard Newton-Raphson method for nonlinear static response and Newmark's time integration technique to obtain nonlinear transient response characteristics. Effect of initial strain on the linear free vibration frequencies, nonlinear static and dynamic response characteristics is investigated in detail. The present multiscale modelling based results are found to be in good agreement with those obtained through molecular mechanics simulation. Two different types of boundary constraints generally used in MM simulation are explored in detail and few interesting findings are brought out. The effect of initial strain is found to be greater in linear response when compared to that in nonlinear response.

Tendon vibration attenuates superficial venous vessel response of the resting limb during static arm exercise

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Ooue Anna

2012-11-01

Full Text Available Abstract Background The superficial vein of the resting limb constricts sympathetically during exercise. Central command is the one of the neural mechanisms that controls the cardiovascular response to exercise. However, it is not clear whether central command contributes to venous vessel response during exercise. Tendon vibration during static elbow flexion causes primary muscle spindle afferents, such that a lower central command is required to achieve a given force without altering muscle force. The purpose of this study was therefore to investigate whether a reduction in central command during static exercise with tendon vibration influences the superficial venous vessel response in the resting limb. Methods Eleven subjects performed static elbow flexion at 35% of maximal voluntary contraction with (EX + VIB and without (EX vibration of the biceps brachii tendon. The heart rate, mean arterial pressure, and rating of perceived exertion (RPE in overall and exercising muscle were measured. The cross-sectional area (CSAvein and blood velocity of the basilic vein in the resting upper arm were assessed by ultrasound, and blood flow (BFvein was calculated using both variables. Results Muscle tension during exercise was similar between EX and EX + VIB. However, RPEs at EX + VIB were lower than those at EX (P P vein in the resting limb at EX decreased during exercise from baseline (P vein at EX + VIB did not change during exercise. CSAvein during exercise at EX was smaller than that at EX + VIB (P vein did not change during the protocol under either condition. The decreases in circulatory response and RPEs during EX + VIB, despite identical muscle tension, showed that activation of central command was less during EX + VIB than during EX. Abolishment of the decrease in CSAvein during exercise at EX + VIB may thus have been caused by a lower level of central command at EX + VIB rather than EX. Conclusion Diminished central command induced by tendon

Development of methods to predict both the dynamic and the pseudo-static response of secondary structures subjected to seismic excitations

International Nuclear Information System (INIS)

Subudhi, M.; Bezler, P.

1984-01-01

Multiple independent support excitation time history formulations have been used to investigate simplified methods to predict the inertial (or dynamic) component of response as well as the pseudo-static (or static) component of response of secondary structures subjected to seismic excitations. For the dynamic component the independent response spectrum method is used with current industry practice for the modal and direction of excitation combinations being adopted and various procedures for the group combination and sequence being investigated. SRSS combination between support groups is found to yield satisfactory results. For the static component, support grouping by elevation for preliminary design followed by support grouping by attachment point for final design assure overall safety in the design

A Minimum Leakage Quasi-Static RAM Bitcell

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Adam Teman

2011-05-01

Full Text Available As SRAMs continue to grow and comprise larger percentages of the area and power consumption in advanced systems, the need to minimize static currents becomes essential. This brief presents a novel 9T Quasi-Static RAM Bitcell that provides aggressive leakage reduction and high write margins. The quasi-static operation method of this cell, based on internal feedback and leakage ratios, minimizes static power while maintaining sufficient, albeit depleted, noise margins. This paper presents the concept of the novel cell, and discusses the stability of the cell under hold, read and write operations. The cell was implemented in a low-power 40 nm TSMC process, showing as much as a 12× reduction in leakage current at typical conditions, as compared to a standard 6T or 8T bitcell at the same supply voltage. The implemented cell showed full functionality under global and local process variations at nominal and low voltages, as low as 300 mV.

Influence of Different Three-Dimensional Open Porous Titanium Scaffold Designs on Human Osteoblasts Behavior in Static and Dynamic Cell Investigations

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Jana Markhoff

2015-08-01

Full Text Available In the treatment of osseous defects micro-structured three-dimensional materials for bone replacement serve as leading structure for cell migration, proliferation and bone formation. The scaffold design and culture conditions are crucial for the limited diffusion distance of nutrients and oxygen. In static culture, decreased cell activity and irregular distribution occur within the scaffold. Dynamic conditions entail physical stimulation and constant medium perfusion imitating physiological nutrient supply and metabolite disposal. Therefore, we investigated the influence of different scaffold configurations and cultivation methods on human osteoblasts. Cells were seeded on three-dimensional porous Ti-6Al-4V scaffolds manufactured with selective laser melting (SLM or electron beam melting (EBM varying in porosity, pore size and basic structure (cubic, diagonal, pyramidal and cultured under static and dynamic conditions. Cell viability, migration and matrix production were examined via mitochondrial activity assay, fluorescence staining and ELISA. All scaffolds showed an increasing cell activity and matrix production under static conditions over time. Expectations about the dynamic culture were only partially fulfilled, since it enabled proliferation alike the static one and enhanced cell migration. Overall, the SLM manufactured scaffold with the highest porosity, small pore size and pyramidal basic structure proved to be the most suitable structure for cell proliferation and migration.

Influence of Different Three-Dimensional Open Porous Titanium Scaffold Designs on Human Osteoblasts Behavior in Static and Dynamic Cell Investigations.

Science.gov (United States)

Markhoff, Jana; Wieding, Jan; Weissmann, Volker; Pasold, Juliane; Jonitz-Heincke, Anika; Bader, Rainer

2015-08-24

In the treatment of osseous defects micro-structured three-dimensional materials for bone replacement serve as leading structure for cell migration, proliferation and bone formation. The scaffold design and culture conditions are crucial for the limited diffusion distance of nutrients and oxygen. In static culture, decreased cell activity and irregular distribution occur within the scaffold. Dynamic conditions entail physical stimulation and constant medium perfusion imitating physiological nutrient supply and metabolite disposal. Therefore, we investigated the influence of different scaffold configurations and cultivation methods on human osteoblasts. Cells were seeded on three-dimensional porous Ti-6Al-4V scaffolds manufactured with selective laser melting (SLM) or electron beam melting (EBM) varying in porosity, pore size and basic structure (cubic, diagonal, pyramidal) and cultured under static and dynamic conditions. Cell viability, migration and matrix production were examined via mitochondrial activity assay, fluorescence staining and ELISA. All scaffolds showed an increasing cell activity and matrix production under static conditions over time. Expectations about the dynamic culture were only partially fulfilled, since it enabled proliferation alike the static one and enhanced cell migration. Overall, the SLM manufactured scaffold with the highest porosity, small pore size and pyramidal basic structure proved to be the most suitable structure for cell proliferation and migration.

Study of the combined action of gamma radiation and static electric fields in human cells

International Nuclear Information System (INIS)

Moron, Michelle Mendes

2008-01-01

The basic principle of radiotherapy is the one of maximizing damage to the tumor, while minimizing it in neighboring health tissues. Several strategies have been worked out aiming at increasing cellular radiosensitivity, and among them is the use of exogenous fields. Our goal in this work is the study in human cells of the effect resulting from the association of irradiation with exposure to exogenous static electric fields. The T47D cell line of breast cancer cells was irradiated with gammas in the 0 - 8 Gy doses range. The corresponding survival curve provided information on the radiosensitivity of this cell line. The rate of cell deaths per Gray in the 0 - 8 Gy range exhibited a maximum at 2 Gy, which corresponds to the most efficient irradiation dose. The viability of this T47D cells exposed to both gamma radiation and 1.250 V/cm static electric field (SEF) was about 12% lower than when only irradiated. The sole exposure of the cells to SEF by 24 and 72 hours didn't induce toxicity. Immunofluorescence runs carried out in irradiated normal MRC5 cell line of human lung fibroblast, without and with exposition to a SEF, have quantified the expression of the y- H2AX histone. The amount of phosphorylated histones was approximately 40% higher after irradiation with 2 Gy plus exposure to a SEF by 1 hour, showing that the electric field negatively interfered in the repairing process of the DNA double strand breaks. The flow cytometry analysis with FACS allowed the investigation of a possible interference of radiation and SEF in the cell distributions among the cellular cycle phases. It was found that in T47D cells treated with 1 and 2 Gy by 24 hours the SEF also negatively interfered in the DNA repairing process, as evidenced by the higher accumulation of cells in the S phase. Therefore, it would be possible to conclude that static and exogenous electric fields are able of negatively interfering in the cellular repair and, presumably, in DNA repair. (author)

Static pressure accelerates ox-LDL-induced cholesterol accumulation via SREBP-1-mediated caveolin-1 downregulation in cultured vascular smooth muscle cells

International Nuclear Information System (INIS)

Luo, Di-xian; Xia, Cheng-lai; Li, Jun-mu; Xiong, Yan; Yuan, Hao-yu; TANG, Zhen-Wang; Zeng, Yixin; Liao, Duan-fang

2010-01-01

Research highlights: → Vertical static pressure accelerates ox-LDL-induced cholesterol accumulation in cultured vascular smooth muscle cells. → Static pressure induces SREBP-1 activation. → Static pressure downregulates the expressions of caveolin-1 by activating SREBP-1. → Static pressure also downregulates the transcription of ABCA1 by activating SREBP-1. → Static pressure increases ox-LDL-induced cholesterol accumulation by SREBP-1-mediated caveolin-1 downregulation in vascular smooth muscle cells cultured in vitro. -- Abstract: Objective: To investigate the effect of static pressure on cholesterol accumulation in vascular smooth muscle cells (VSMCs) and its mechanism. Methods: Rat-derived VSMC cell line A10 treated with 50 mg/L ox-LDL and different static pressures (0, 60, 90, 120, 150, 180 mm Hg) in a custom-made pressure incubator for 48 h. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC; The mRNA levels of caveolin-1 and ABCA1, the protein levels of caveolin-1 SREBP-1 and mature SREBP-1 were respectively detected by RT-PCR or western blot. ALLN, an inhibitor of SREBP metabolism, was used to elevate SREBP-1 protein level in VSMCs treated with static pressure. Results: Static pressures significantly not only increase intracellular lipid droplets in VSMCs, but also elevate cellular lipid content in a pressure-dependent manner. Intracellular free cholesterol (FC), cholesterol ester (CE), total cholesterol (TC) were respectively increased from 60.5 ± 2.8 mg/g, 31.8 ± 0.7 mg/g, 92.3 ± 2.1 mg/g at atmosphere pressure (ATM, 0 mm Hg) to 150.8 ± 9.4 mg/g, 235.9 ± 3.0 mg/g, 386.7 ± 6.4 mg/g at 180 mm Hg. At the same time, static pressures decrease the mRNA and protein levels of caveolin-1, and induce the activation and nuclear translocation of SREBP-1. ALLN increases the protein level of mature SREBP-1 and decreases caveolin-1 expression, so that cellular lipid levels were upregulated. Conclusion: Static

Static pressure accelerates ox-LDL-induced cholesterol accumulation via SREBP-1-mediated caveolin-1 downregulation in cultured vascular smooth muscle cells

Energy Technology Data Exchange (ETDEWEB)

Luo, Di-xian, E-mail: luodixian_2@163.com [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); First People' s Hospital of Chenzhou City, Chenzhou 423000, Hunan (China); Xia, Cheng-lai [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Pharmacy, Third Affiliated Hospital Medical College of Guangzhou, Guangzhou 510150, Guangdong (China); Li, Jun-mu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Xiong, Yan [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Yuan, Hao-yu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Lusong Center for Disease Control and Prevention, Zhuzhou 412000, Hunan (China); TANG, Zhen-Wang; Zeng, Yixin [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Liao, Duan-fang, E-mail: dfliao66@yahoo.com.cn [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Traditional Chinese Diagnostics, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 420108, Hunan (China)

2010-12-03

Research highlights: {yields} Vertical static pressure accelerates ox-LDL-induced cholesterol accumulation in cultured vascular smooth muscle cells. {yields} Static pressure induces SREBP-1 activation. {yields} Static pressure downregulates the expressions of caveolin-1 by activating SREBP-1. {yields} Static pressure also downregulates the transcription of ABCA1 by activating SREBP-1. {yields} Static pressure increases ox-LDL-induced cholesterol accumulation by SREBP-1-mediated caveolin-1 downregulation in vascular smooth muscle cells cultured in vitro. -- Abstract: Objective: To investigate the effect of static pressure on cholesterol accumulation in vascular smooth muscle cells (VSMCs) and its mechanism. Methods: Rat-derived VSMC cell line A10 treated with 50 mg/L ox-LDL and different static pressures (0, 60, 90, 120, 150, 180 mm Hg) in a custom-made pressure incubator for 48 h. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC; The mRNA levels of caveolin-1 and ABCA1, the protein levels of caveolin-1 SREBP-1 and mature SREBP-1 were respectively detected by RT-PCR or western blot. ALLN, an inhibitor of SREBP metabolism, was used to elevate SREBP-1 protein level in VSMCs treated with static pressure. Results: Static pressures significantly not only increase intracellular lipid droplets in VSMCs, but also elevate cellular lipid content in a pressure-dependent manner. Intracellular free cholesterol (FC), cholesterol ester (CE), total cholesterol (TC) were respectively increased from 60.5 {+-} 2.8 mg/g, 31.8 {+-} 0.7 mg/g, 92.3 {+-} 2.1 mg/g at atmosphere pressure (ATM, 0 mm Hg) to 150.8 {+-} 9.4 mg/g, 235.9 {+-} 3.0 mg/g, 386.7 {+-} 6.4 mg/g at 180 mm Hg. At the same time, static pressures decrease the mRNA and protein levels of caveolin-1, and induce the activation and nuclear translocation of SREBP-1. ALLN increases the protein level of mature SREBP-1 and decreases caveolin-1 expression, so that cellular lipid levels were

A computational methodology for a micro launcher engine test bench using a combined linear static and dynamic in frequency response analysis

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Ion DIMA

2017-03-01

Full Text Available This article aims to provide a quick methodology to determine the critical values of the forces, displacements and stress function of frequency, under a combined linear static (101 Solution - Linear Static and dynamic load in frequency response (108 Solution - Frequency Response, Direct Method, applied to a micro launcher engine test bench, using NASTRAN 400 Solution - Implicit Nonlinear. NASTRAN/PATRAN software is used. Practically in PATRAN the preprocessor has to define a linear or nonlinear static load at step 1 and a dynamic in frequency response load (time dependent at step 2. In Analyze the following options are chosen: for Solution Type Implicit Nonlinear Solution (SOL 400 is selected, for Subcases Static Load and Transient Dynamic is chosen and for Subcase Select the two cases static and dynamic will be selected. NASTRAN solver will overlap results from static analysis with the dynamic analysis. The running time will be reduced three times if using Krylov solver. NASTRAN SYSTEM (387 = -1 instruction is used in order to activate Krylov option. Also, in Analysis the OP2 Output Format shall be selected, meaning that in bdf NASTRAN input file the PARAM POST 1 instruction shall be written. The structural damping can be defined in two different ways: either at the material card or using the PARAM, G, 0.05 instruction (in this example a damping coefficient by 5% was used. The SDAMPING instruction in pair with TABDMP1 work only for dynamic in frequency response, modal method, or in direct method with viscoelastic material, not for dynamic in frequency response, direct method (DFREQ, with linear elastic material. The Direct method – DFREQ used in this example is more accurate. A set in translation of boundary conditions was used and defined at the base of the test bench.

Responsiveness of Static and Dynamic Postural Balance Measures in Patients with Anterior Cruciate Ligament Reconstruction Following Physiotherapy Intervention

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Neda Mostafaee

2017-05-01

Full Text Available Background:The main goal of physiotherapy for patients with anterior cruciate ligament reconstruction (ACL-R is to improve postural control and retain knee function. Therefore, clinicians need to use evaluative tools that assess postural changes during physiotherapy. To maximize the clinical utility of the results of these tools, the extracted measures should have appropriate psychometric properties of reliability, validity and responsiveness. No study has yet addressed responsiveness of postural measures in these patients. This study was designed to investigate the responsiveness and determine the minimal clinically important changes (MCIC of static and dynamic postural measures in patients with (ACL-R following physiotherapy. Methods: Static and dynamic postural measures were evaluated at first occasion and again after four weeks physiotherapy. The static measures consisted of center of pressure (COP parameters while dynamic measures included the stability indices. Correlation analysis and ROC curve were applied for assessing the responsiveness. Results:The meanand SD velocity of COP had acceptable responsiveness in both conditions of standing on injured leg with open-eyes and on uninjured leg with closed-eyes, both with nocognitive task. For dynamic measures, stability indices in double-leg standing with closed-eyes with cognitive task condition attained acceptable responsiveness. MCICs for mean and SD velocity in anteroposterior and mediolateral directions were 0.28cm/s, 0.008cm/s, 0.02cm/s, respectively in standing on injured leg with open-eyes; and 0.14cm/s, 0.07cm/s, 0.06cm/s, respectively in uninjured leg with closed-eyes condition. Also, MCICs for anteroposterior, mediolateral and total stability indices were 0.51◦, 0.37◦, 0.34◦, respectively in DCT condition. Conclusion:Our findings provide evidence for selection of appropriate static and dynamic postural measures for assessment of changes in these patients. MCICs for these

Static compression down-regulates N-cadherin expression and facilitates loss of cell phenotype of nucleus pulposus cells in a disc perfusion culture.

Science.gov (United States)

Zhou, Haibo; Shi, Jianmin; Zhang, Chao; Li, Pei

2018-02-28

Mechanical compression often induces degenerative changes of disc nucleus pulposus (NP) tissue. It has been indicated that N-cadherin (N-CDH)-mediated signaling helps to preserve the NP cell phenotype. However, N-CDH expression and the resulting NP-specific phenotype alteration under the static compression and dynamic compression remain unclear. To study the effects of static compression and dynamic compression on N-CDH expression and NP-specific phenotype in an in vitro disc organ culture. Porcine discs were organ cultured in a self-developed mechanically active bioreactor for 7 days and subjected to static or dynamic compression (0.4 MPa for 2 h once per day). The noncompressed discs were used as controls. Compared with the dynamic compression, static compression significantly down-regulated the expression of N-CDH and NP-specific markers (laminin, brachyury, and keratin 19); decreased the Alcian Blue staining intensity, glycosaminoglycan and hydroxyproline contents; and declined the matrix macromolecule (aggrecan and collagen II) expression. Compared with the dynamic compression, static compression causes N-CDH down-regulation, loss of NP-specific phenotype, and the resulting decrease in NP matrix synthesis. © 2018 The Author(s).

Response of exfoliated human buccal epithelium cells to combined gamma radiation, microwaves, and magnetic field exposure estimated by changes in chromatin condensation and cell membrane permeability

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K. А. Kuznetsov

2016-11-01

Full Text Available Modulation of the biological effects produced by ionizing radiation (IR using microwave and magnetic fields has important theoretical and practical applications. Response of human buccal epithelium cells to different physical agents (single and combined exposure to 0.5–5 Gy γ-radiation (60Co; microwaves with the frequency of 36.64 GHz and power densities of 0.1 and 1 W/m2, and static magnetic field with the intensity of 25 mT has been investigated. The stress response of the cells was evaluated by counting heterochromatin granules quantity (HGQ in the cell nuclei stained with orcein. Membrane permeability was assessed by the percentage of cells stained with indigocarmine (cells with damaged membrane. The increase of heterochromatin granules quantity (HGQ, i.e. chromatin condensation was detected at the doses of 2 Gy and higher. Changes in the cell membrane permeability to indigocarmine expressed the threshold effect. Membrane permeability reached the threshold at the doses of 2–3 Gy for the cells of different donors and did not change with the increase of the dose of γ-radiation. Cells obtained from different donors revealed some individual peculiarities in their reaction to γ-radiation. The static magnetic field and microwaves applied before or after γ-radiation decreased its impact, as revealed by means of HGQ assessment.

Static inverter with synchronous output waveform synthesized by time-optimal-response feedback

Science.gov (United States)

Kernick, A.; Stechschulte, D. L.; Shireman, D. W.

1976-01-01

Time-optimal-response 'bang-bang' or 'bang-hang' technique, using four feedback control loops, synthesizes static-inverter sinusoidal output waveform by self-oscillatory but yet synchronous pulse-frequency-modulation (SPFM). A single modular power stage per phase of ac output entails the minimum of circuit complexity while providing by feedback synthesis individual phase voltage regulation, phase position control and inherent compensation simultaneously for line and load disturbances. Clipped sinewave performance is described under off-limit load or input voltage conditions. Also, approaches to high power levels, 3-phase arraying and parallel modular connection are given.

The effect of low static magnetic field on osteogenic and adipogenic differentiation potential of human adipose stromal/stem cells

Energy Technology Data Exchange (ETDEWEB)

Marędziak, Monika, E-mail: monika.maredziak@gmail.com [Faculty of Veterinary Medicine, University of Environmental and Life Sciences, Wrocław (Poland); Wroclaw Research Centre EIT+, Wrocław (Poland); Śmieszek, Agnieszka, E-mail: smieszek.agnieszka@gmail.com [Wroclaw Research Centre EIT+, Wrocław (Poland); Faculty of Biology, University of Environmental and Life Sciences, Wrocław (Poland); Tomaszewski, Krzysztof A., E-mail: krtomaszewski@gmail.com [Department of Anatomy, Jagiellonian University Medical College, Krakow (Poland); Lewandowski, Daniel, E-mail: daniel.lewandowski@pwr.wroc.pl [Institute of Materials Science and Applied Mechanics, Wroclaw University of Technology, Wroclaw (Poland); Marycz, Krzysztof, E-mail: krzysztofmarycz@interia.pl [Wroclaw Research Centre EIT+, Wrocław (Poland); Faculty of Biology, University of Environmental and Life Sciences, Wrocław (Poland)

2016-01-15

The aim of this work was to investigate the effects of static magnetic field (SMF) on the osteogenic properties of human adipose derived mesenchymal stem cells (hASCs). In this study in seven days viability assay we examined the impact of SMF on cells proliferation rate, population doubling time, and ability to form single-cell derived colonies. We have also examined cells' morphology, ultrastructure and osteogenic properties on the protein as well as mRNA level. We established a complex approach, which enabled us to obtain information about SMF and hASCs potential in the context of differentiation into osteogenic and adipogenic lineages. We demonstrated that SMF enhances both viability and osteogenic properties of hASCs through higher proliferation factor and shorter population doubling time. We have also observed asymmetrically positioned nuclei and organelles after SMF exposition. With regards to osteogenic properties we observed increased levels of osteogenic markers i.e. osteopontin, osteocalcin and increased ability to form osteonodules with positive reaction to Alizarin Red dye. We have also shown that SMF besides enhancing osteogenic properties of hASCs, simultaneously decreases their ability to differentiate into adipogenic lineage. Our results clearly show a direct influence of SMF on the osteogenic potential of hASCs. These results provide key insights into the role of SMF on their cellular fate and properties. - Graphical abstract: Influence of static magnetic field on viability and differentiation properties of human adipose derived mesenchymal stem cells. Abbreviations: SMF – static magnetic field; hASCs – human adipose derived mesenchymal stem cells; PF – proliferation factor; PDT – population doubling time; CFU-E –> colony forming unit efficiency; OPN – osteopontin; OCL – osteocalcin; Col – collagen type I; BMP-2 – bone morphogenetic protein 2; Ca – calcium; P – phosphorus. - Highlights: • Effects of static

The effect of low static magnetic field on osteogenic and adipogenic differentiation potential of human adipose stromal/stem cells

International Nuclear Information System (INIS)

Marędziak, Monika; Śmieszek, Agnieszka; Tomaszewski, Krzysztof A.; Lewandowski, Daniel; Marycz, Krzysztof

2016-01-01

The aim of this work was to investigate the effects of static magnetic field (SMF) on the osteogenic properties of human adipose derived mesenchymal stem cells (hASCs). In this study in seven days viability assay we examined the impact of SMF on cells proliferation rate, population doubling time, and ability to form single-cell derived colonies. We have also examined cells' morphology, ultrastructure and osteogenic properties on the protein as well as mRNA level. We established a complex approach, which enabled us to obtain information about SMF and hASCs potential in the context of differentiation into osteogenic and adipogenic lineages. We demonstrated that SMF enhances both viability and osteogenic properties of hASCs through higher proliferation factor and shorter population doubling time. We have also observed asymmetrically positioned nuclei and organelles after SMF exposition. With regards to osteogenic properties we observed increased levels of osteogenic markers i.e. osteopontin, osteocalcin and increased ability to form osteonodules with positive reaction to Alizarin Red dye. We have also shown that SMF besides enhancing osteogenic properties of hASCs, simultaneously decreases their ability to differentiate into adipogenic lineage. Our results clearly show a direct influence of SMF on the osteogenic potential of hASCs. These results provide key insights into the role of SMF on their cellular fate and properties. - Graphical abstract: Influence of static magnetic field on viability and differentiation properties of human adipose derived mesenchymal stem cells. Abbreviations: SMF – static magnetic field; hASCs – human adipose derived mesenchymal stem cells; PF – proliferation factor; PDT – population doubling time; CFU-E –> colony forming unit efficiency; OPN – osteopontin; OCL – osteocalcin; Col – collagen type I; BMP-2 – bone morphogenetic protein 2; Ca – calcium; P – phosphorus. - Highlights: • Effects of static

Sub-1-V-60 nm vertical body channel MOSFET-based six-transistor static random access memory array with wide noise margin and excellent power delay product and its optimization with the cell ratio on static random access memory cell

Science.gov (United States)

Ogasawara, Ryosuke; Endoh, Tetsuo

2018-04-01

In this study, with the aim to achieve a wide noise margin and an excellent power delay product (PDP), a vertical body channel (BC)-MOSFET-based six-transistor (6T) static random access memory (SRAM) array is evaluated by changing the number of pillars in each part of a SRAM cell, that is, by changing the cell ratio in the SRAM cell. This 60 nm vertical BC-MOSFET-based 6T SRAM array realizes 0.84 V operation under the best PDP and up to 31% improvement of PDP compared with the 6T SRAM array based on a 90 nm planar MOSFET whose gate length and channel width are the same as those of the 60 nm vertical BC-MOSFET. Additionally, the vertical BC-MOSFET-based 6T SRAM array achieves an 8.8% wider read static noise margin (RSNM), a 16% wider write margin (WM), and an 89% smaller leakage. Moreover, it is shown that changing the cell ratio brings larger improvements of RSNM, WM, and write time in the vertical BC-MOSFET-based 6T SRAM array.

Mechanical response of common millet (Panicum miliaceum) seeds under quasi-static compression: Experiments and modeling.

Science.gov (United States)

Hasseldine, Benjamin P J; Gao, Chao; Collins, Joseph M; Jung, Hyun-Do; Jang, Tae-Sik; Song, Juha; Li, Yaning

2017-09-01

The common millet (Panicum miliaceum) seedcoat has a fascinating complex microstructure, with jigsaw puzzle-like epidermis cells articulated via wavy intercellular sutures to form a compact layer to protect the kernel inside. However, little research has been conducted on linking the microstructure details with the overall mechanical response of this interesting biological composite. To this end, an integrated experimental-numerical-analytical investigation was conducted to both characterize the microstructure and ascertain the microscale mechanical properties and to test the overall response of kernels and full seeds under macroscale quasi-static compression. Scanning electron microscopy (SEM) was utilized to examine the microstructure of the outer seedcoat and nanoindentation was performed to obtain the material properties of the seedcoat hard phase material. A multiscale computational strategy was applied to link the microstructure to the macroscale response of the seed. First, the effective anisotropic mechanical properties of the seedcoat were obtained from finite element (FE) simulations of a microscale representative volume element (RVE), which were further verified from sophisticated analytical models. Then, macroscale FE models of the individual kernel and full seed were developed. Good agreement between the compression experiments and FE simulations were obtained for both the kernel and the full seed. The results revealed the anisotropic property and the protective function of the seedcoat, and showed that the sutures of the seedcoat play an important role in transmitting and distributing loads in responding to external compression. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of Static and Dynamic Properties of Micromirror with the Application of Response Surface Method

Directory of Open Access Journals (Sweden)

A Martowicz

2016-09-01

Full Text Available The paper presents the results of an application of response surface method to aid the analysis of variation of static and dynamic properties of micromirror. The multiphysics approach was taken into account to elaborate finite element model of electrostatically actuated microdevice and coupled analyses were carried out to yield the results. Used procedure of metamodel fitting is described and its quality is discussed. Elaborated approximations were used to perform the sensitivity analysis as well as to study the propagation of variation introduced by uncertain and control parameters. The input parameters deal with geometry, material properties and control voltage. As studied output characteristics there were chosen the resultant static vertical displacement of reflecting surfaces and the resonance frequency related to the first normal mode of vibration.

Hard thermal loops, static response, and the composite effective action

International Nuclear Information System (INIS)

Jackiw, R.; Liu, Q.; Lucchesi, C.

1994-01-01

First, we investigate the static non-Abelian Kubo equation. We prove that it does not possess finite energy solutions; thereby we establish that gauge theories do not support hard thermal solitons. This general result is verified by a numerical solution of the equations. A similar argument shows that ''static'' instantons are absent. In addition, we note that the static equations reproduce the expected screening of the non-Abelian electric field by a gauge-invariant Debye mass m=gT √(N+N F /2)/3 . Second, we derive the non-Abelian Kubo equation from the composite effective action. This is achieved by showing that the requirement of stationarity of the composite effective action is equivalent, within a kinematical approximation scheme, to the condition of gauge invariance for the generating functional of hard thermal loops

Evaluation of static and dynamic MRI for assessing response of bone sarcomas to preoperative chemotherapy: Correlation with histological necrosis

International Nuclear Information System (INIS)

Amit, Priyadarshi; Malhotra, Atul; Kumar, Rahul; Kumar, Lokesh; Patro, Dilip Kumar; Elangovan, Sundar

2015-01-01

Preoperative chemotherapy plays a key role in management of bone sarcomas. Postoperative evaluation of histological necrosis has been the gold standard method of assessing response to preoperative chemotherapy. This study was done to evaluate the efficacy of static and dynamic magnetic resonance imaging (MRI) for assessing response preoperatively. Our study included 14 patients (12 osteosarcomas and 2 malignant fibrous histiocytomas) with mean age of 21.8 years, treated with preoperative chemotherapy followed by surgery. They were evaluated with static and dynamic MRI twice, before starting chemotherapy and again prior to surgery. Change in tumor volume and slope of signal intensity - time curve were calculated and correlated with percentage of histological necrosis using Pearson correlation test. The change in dynamic MRI slope was significant (P = 0.001). Also, ≥60% reduction in slope of the curve proved to be an indicator of good histological response [positive predictive value (PPV) =80%]. Change in tumor volume failed to show significant correlation (P = 0.071). Although it showed high negative predictive value (NPV = 85.7%), PPV was too low (PPV = 57.14%). Dynamic MRI correctly predicts histological necrosis after administration of preoperative chemotherapy to bone sarcomas. Hence, it can be used as a preoperative indicator of response to neoadjuvant chemotherapy. On the other hand, volumetric assessment by static MRI is not an effective predictor of histological necrosis. This study proves the superiority of dynamic contrast-enhanced study over volumetric study by MRI

Blood pressure response to low level static contractions

DEFF Research Database (Denmark)

Fallentin, Nils; Jørgensen, Kurt

1992-01-01

The present study re-examines the 15% MVC concept, i.e. the existence of a circulatory steady-state in low intensity static contractions below 15% of maximal voluntary contraction (MVC). Mean arterial blood pressure was studied during static endurance contractions of the elbow flexor and extensor...... 0.7) min for elbow extension]. Mean arterial blood pressure exhibited a continuous and progressive increase during the 10% MVC contractions indicating that the 15% MVC concept would not appear to be valid. The terminal blood pressure value recorded at the point of exhaustion in the 10% MVC elbow...... the circulation to the muscles was arrested just prior to the cessation of the contraction, blood pressure only partly recovered and remained elevated for as long as the occlusion persisted, indicating the level of pressure-raising muscle chemoreflexes. Based on blood pressure recordings obtained during...

Estimation of genetic effects of static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheats

International Nuclear Information System (INIS)

Zhang Pingping; Yin Ruochun; Tang Mingli; Wu Yuejin; Yu Zengliang

2007-01-01

The effect of static magnetic fields (SMFs) on the chromosome aberrations in the pollen mother cells (PMCs) of wheat was studied. The seeds of wheat were exposed to static magnetic fields of different magnetic flux density (0, 1, 3, 5 and 7 Tesla) for 5h and with different treated time (1, 3 and 5h) at magnetic flux density of 7 Tesla. The genotoxic effect was evaluated in terms of micronucleus (MN), chromosomal bridge, lagging chromosome, abnormal segregation and fragment in PMCs. The results indicated that the exposed groups of low field intensity (below 5 Tesla) showed no statistically significant difference in aberration frequency compared with unexposed control groups and sham exposed groups, but significant differences of chromosomal bridge at 5T and lagging chromosome, triple-polar segregation or micronucleus at 7T were detected in the exposed group (p<0.05). The dose-effect relationships indicated that the increase frequency of meiotic abnormal cells correlated with flux density of magnetic field and treated time, but no linear effect was observed. These results lead us to the conclusion that high static magnetic fields above 5T for 5h duration might cause an increase in potential damage to organisms. (authors)

Comparison of cardiovascular response to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone in patients with chronic ischemic heart disease

International Nuclear Information System (INIS)

Hung, J.; McKillip, J.; Savin, W.; Magder, S.; Kraus, R.; Houston, N.; Goris, M.; Haskell, W.; DeBusk, R.

1982-01-01

The cardiovascular responses to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone were evaluated by upright bicycle ergometry during equilibrium-gated blood pool scintigraphy in 24 men, mean age 59 +/- 8 years, with chronic ischemic heart disease. Combined static-dynamic effort and the postprandial state elicited a peak cardiovascular response similar to that of dynamic effort alone. Heart rate, intraarterial systolic and diastolic pressures, rate-pressure product and ejection fraction were similar for the three test conditions at the onset of ischemia and at peak effort. The prevalence and extent of exercise-induced ischemic left ventricular dysfunction, ST-segment depression, angina pectoris and ventricular ectopic activity were also similar during the three test conditions. Direct and indirect measurements of systolic and diastolic blood pressure were highly correlated. The onset of ischemic ST-segment depression and angina pectoris correlated as strongly with heart rate alone as with the rate-pressure product during all three test conditions. The cardiovascular response to combined static-dynamic effort and to postprandial dynamic effort becomes more similar to that of dynamic effort alone as dynamic effort reaches a symptom limit. If significant ischemic and arrhythmic abnormalities are absent during symptom-limited dynamic exercise testing, they are unlikely to appear during combined static-dynamic or postprandial dynamic effort

Influence of static magnetic fields in phototaxis and osmotic stress in Gymnodinium catenatum (Dinophyceae).

Science.gov (United States)

Vale, Paulo

2017-07-01

Phototaxis response of the toxic microalgae Gymnodinium catenatum was studied in vitro. The percentage of cells remaining at mid-depth 20 min after stirring increased with solar radio, X-ray and solar flares output. It also increased with geomagnetic activity and temperature, and was dependent on culture time. Increase in the local static magnetic field with a permanent magnet did not influence the positive phototaxis response. However, survival and growth to a provoked hypo-osmotic shock in an altered static magnetic field was dependent on culture time and geomagnetic activity at a threshold below 22 nT. The results from phototaxis and hypo-osmotic shock experiments were in line with the previous hypothesis for the existence of two separate deleterious mechanisms conditioning the natural blooms of G. catenatum: one that is dependent on solar radiation and the other that is related to geomagnetic activity. Variations in electromagnetic fields caused by tectonic activity were also capable of influencing G. catenatum phototaxis and growth response in vitro.

Genotoxic Effects of Superconducting Static Magnetic Fields (SMFs) on Wheat (Triticum aestivum) Pollen Mother Cells (PMCs)

Science.gov (United States)

Zhang, Pingping; Yin, Ruochun; Chen, Zhiyou; Wu, Lifang; Yu, Zengliang

2007-04-01

The effects of superconducting static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities (0, 1, 3, 5 and 7 Tesla) for 5 h or different durations (1, 3 and 5 h) at a magnetic flux density of 7 Tesla. The seeds were germinated at 23oC after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus (MN), chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity (below 5 Tesla) showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.

Genotoxic Effects of Superconducting Static Magnetic Fields (SMFs) on Wheat (Triticum aestivum) Pollen Mother Cells (PMCs)

International Nuclear Information System (INIS)

Zhang Pingping; Yin Ruochun; Chen Zhiyou; Wu Lifang; Yu Zengliang

2007-01-01

The effects of superconducting static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities (0, 1, 3, 5 and 7 Tesla) for 5 h or different durations (1, 3 and 5 h) at a magnetic flux density of 7 Tesla. The seeds were germinated at 23 o C after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus (MN), chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity (below 5 Tesla) showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T

The cell envelope stress response of Bacillus subtilis: from static signaling devices to dynamic regulatory network.

Science.gov (United States)

Radeck, Jara; Fritz, Georg; Mascher, Thorsten

2017-02-01

The cell envelope stress response (CESR) encompasses all regulatory events that enable a cell to protect the integrity of its envelope, an essential structure of any bacterial cell. The underlying signaling network is particularly well understood in the Gram-positive model organism Bacillus subtilis. It consists of a number of two-component systems (2CS) and extracytoplasmic function σ factors that together regulate the production of both specific resistance determinants and general mechanisms to protect the envelope against antimicrobial peptides targeting the biogenesis of the cell wall. Here, we summarize the current picture of the B. subtilis CESR network, from the initial identification of the corresponding signaling devices to unraveling their interdependence and the underlying regulatory hierarchy within the network. In the course of detailed mechanistic studies, a number of novel signaling features could be described for the 2CSs involved in mediating CESR. This includes a novel class of so-called intramembrane-sensing histidine kinases (IM-HKs), which-instead of acting as stress sensors themselves-are activated via interprotein signal transfer. Some of these IM-HKs are involved in sensing the flux of antibiotic resistance transporters, a unique mechanism of responding to extracellular antibiotic challenge.

The optimization of essential oils supercritical CO2 extraction from Lavandula hybrida through static-dynamic steps procedure and semi-continuous technique using response surface method

Science.gov (United States)

Kamali, Hossein; Aminimoghadamfarouj, Noushin; Golmakani, Ebrahim; Nematollahi, Alireza

2015-01-01

Aim: The aim of this study was to examine and evaluate crucial variables in essential oils extraction process from Lavandula hybrida through static-dynamic and semi-continuous techniques using response surface method. Materials and Methods: Essential oil components were extracted from Lavandula hybrida (Lavandin) flowers using supercritical carbon dioxide via static-dynamic steps (SDS) procedure, and semi-continuous (SC) technique. Results: Using response surface method the optimum extraction yield (4.768%) was obtained via SDS at 108.7 bar, 48.5°C, 120 min (static: 8×15), 24 min (dynamic: 8×3 min) in contrast to the 4.620% extraction yield for the SC at 111.6 bar, 49.2°C, 14 min (static), 121.1 min (dynamic). Conclusion: The results indicated that a substantial reduction (81.56%) solvent usage (kg CO2/g oil) is observed in the SDS method versus the conventional SC method. PMID:25598636

Statics and rotational dynamics of composite beams

CERN Document Server

Ghorashi, Mehrdaad

2016-01-01

This book presents a comprehensive study of the nonlinear statics and dynamics of composite beams and consists of solutions with and without active elements embedded in the beams. The static solution provides the initial conditions for the dynamic analysis. The dynamic problems considered include the analyses of clamped (hingeless) and articulated (hinged) accelerating rotating beams. Two independent numerical solutions for the steady state and the transient responses are presented. The author illustrates that the transient solution of the nonlinear formulation of accelerating rotating beam converges to the steady state solution obtained by the shooting method. Other key areas considered include calculation of the effect of perturbing the steady state solution, coupled nonlinear flap-lag dynamics of a rotating articulated beam with hinge offset and aerodynamic damping, and static and dynamic responses of nonlinear composite beams with embedded anisotropic piezo-composite actuators. The book is intended as a t...

Secretory production of cell wall components by Saccharomyces cerevisiae protoplasts in static liquid culture.

Science.gov (United States)

Aoyagi, Hideki; Ishizaka, Mikiko; Tanaka, Hideo

2012-04-01

When protoplasts of Saccharomyces cerevisiae T7 and IFO 0309 are cultured in a static liquid culture at 2.5 × 10(6) protoplasts/ml, cell wall regeneration does not occur and cell wall components (CWC) are released into the culture broth. By using a specialized fluorometer, the concentrations of CWC could be measured on the basis of the fluorescence intensity of the CWC after staining with Fluostain I. The inoculum concentration, pH, and osmotic pressure of the medium were important factors for the production of CWC in culture. Under optimal culture conditions, S. cerevisiae T7 protoplasts produced 0.91 mg/ml CWC after 24 h. The CWC induced the tumor necrosis factor-α production about 1.3 times higher than that of the commercially available β-1,3/1,6-glucan from baker's yeast cells.

The dynamic and quasi-static mechanical response of three aluminum armor alloys: 5059, 5083 and 7039

Energy Technology Data Exchange (ETDEWEB)

Perez-Bergquist, Sara J., E-mail: sara.perezbergquist@gmail.com [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87545 (United States); Gray, G.T.; Cerreta, Ellen K.; Trujillo, Carl P.; Perez-Bergquist, Alex [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87545 (United States)

2011-11-15

Highlights: {yields} Aluminum alloys for use in armor applications. {yields} Mechanical response in dynamic and quasi-static regimes with temperature dependence. {yields} Shear localization with evidence of early stages of dynamic recrystallization. - Abstract: The mechanical response and microstructural evolution of aluminum alloys 5083, 5059 and 7039 was examined in compression and shear in both the quasi-static (0.001 s{sup -1}) and dynamic ({approx}2000 s{sup -1}) strain rate regimes. Electron Back Scattered Diffraction was utilized for detailed post-mortem analysis of the specimens following loading. The mechanical responses in shear were found to be strain-rate sensitive. At the slowest strain rates, all of the alloys had relatively large volumes of highly deformed material with 5083 and 5059 having the largest shear affected volumes. The dynamic strain rate test samples all formed highly compact shear localized volumes across the sheared zone with 7039 consistently displaying the narrowest shear regions. The morphology of these shear bands, along with the limited hardening during deformation, indicate a mechanism change at the higher strain rates. Higher resolution orientation image mapping has shown that between the three alloys there are varying degrees of crystallographic order within the shear bands. Transmission electron microscopy revealed various stages of dynamic recrystallization were present suggesting that while low strain rate deformation is controlled by dislocation multiplication and glide, high strain and strain-rate deformation is influenced in part due to mechanical recrystallization.

Decidual Stromal Cell Response to Paracrine Signals from the Trophoblast: Amplification of Immune and Angiogenic Modulators

DEFF Research Database (Denmark)

Hess, AP; Hamilton, AE; Talbi, S

2007-01-01

During the invasive phase of implantation, trophoblasts and maternal decidual stromal cells secrete products that regulate trophoblast differentiation and migration into the maternal endometrium. Paracrine interactions between the extravillous trophoblast and the maternal decidua are important...... a functional genomics approach to investigate these paracrine interactions. Human endometrial stromal cells were decidualized with progesterone and were further treated with conditioned media (CM) from human trophoblasts (TCM) or, as a control, with conditioned media (CCM) from non-decidualized stromal cells...... regulated groups. The data demonstrate a significant induction of pro-inflammatory cytokines and chemokines, as well as angiogenic/static factors in decidualized endometrial stromal cells in response to trophoblast-secreted products. The data suggest that the trophoblast acts to alter the local immune...

MUSIC-type imaging of a thin penetrable inclusion from its multi-static response matrix

International Nuclear Information System (INIS)

Park, Won-Kwang; Lesselier, Dominique

2009-01-01

The imaging of a thin inclusion, with dielectric and/or magnetic contrasts with respect to the embedding homogeneous medium, is investigated. A MUSIC-type algorithm operating at a single time-harmonic frequency is developed in order to map the inclusion (that is, to retrieve its supporting curve) from scattered field data collected within the multi-static response matrix. Numerical experiments carried out for several types of inclusions (dielectric and/or magnetic ones, straight or curved ones), mostly single inclusions and also two of them close by as a straightforward extension, illustrate the pros and cons of the proposed imaging method

MUSIC-type imaging of a thin penetrable inclusion from its multi-static response matrix

Science.gov (United States)

Park, Won-Kwang; Lesselier, Dominique

2009-07-01

The imaging of a thin inclusion, with dielectric and/or magnetic contrasts with respect to the embedding homogeneous medium, is investigated. A MUSIC-type algorithm operating at a single time-harmonic frequency is developed in order to map the inclusion (that is, to retrieve its supporting curve) from scattered field data collected within the multi-static response matrix. Numerical experiments carried out for several types of inclusions (dielectric and/or magnetic ones, straight or curved ones), mostly single inclusions and also two of them close by as a straightforward extension, illustrate the pros and cons of the proposed imaging method.

Observing the Forces Involved in Static Friction under Static Situations

Science.gov (United States)

Kaplan, Daniel

2013-01-01

Static friction is an important concept in introductory physics. Later in the year students apply their understanding of static friction under more complex conditions of static equilibrium. Traditional lab demonstrations in this case involve exceeding of the maximum level of static friction, resulting in the "onset of motion." (Contains…

Evaluation of Advanced Nonlinear Static Procedure

Directory of Open Access Journals (Sweden)

Mohsen Ali Shayanfar

2015-03-01

Full Text Available Having very simplicity, nonlinear static procedures (NSPs are the most popular tools for estimation of structural capacity. These approaches construct a graphic display of the overall structural response via a pushover curve. The overall response of the system provides a direct simulation of the building as single degree of freedom (SDOF system that simplifies the design and evaluation of the structure. In this research, the first step in any nonlinear static analysis or in other words perform a pushover analysis has been studied. Applied lateral load to the structural model not only affects the overall responses of the structure through structural capacity curve, but also directly affects the local responses of the structure. In order to evaluate these lateral loads, steel buckling restrained braced frame structures are examined by advanced modal pushovers. Next, the results of these pushover analyses will be compared with nonlinear time history analysis as the most accurate method. Finally, the most efficient method in this particular structure is introduced. The analysis conducted in these structures shows that the lateral load pattern based on story shears offers a good prediction of the maximum response of the concentrically buckling restrained braced frame buildings.

Transient Response Dynamic Module Modifications to Include Static and Kinetic Friction Effects

Science.gov (United States)

Misel, J. E.; Nenno, S. B.; Takahashi, D.

1984-01-01

A methodology that supports forced transient response dynamic solutions when both static and kinetic friction effects are included in a structural system model is described. Modifications that support this type of nonlinear transient response solution are summarized for the transient response dynamics (TRD) NASTRAN module. An overview of specific modifications for the NASTRAN processing subroutines, INITL, TRD1C, and TRD1D, are described with further details regarding inspection of nonlinear input definitions to define the type of nonlinear solution required, along with additional initialization requirements and specific calculation subroutines to successfully solve the transient response problem. The extension of the basic NASTRAN nonlinear methodology is presented through several stages of development to the point where constraint equations and residual flexibility effects are introduced into the finite difference Newmark-Beta recurrsion formulas. Particular emphasis is placed on cost effective solutions for large finite element models such as the Space Shuttle with friction degrees of freedom between the orbiter and payloads mounted in the cargo bay. An alteration to the dynamic finite difference equations of motion is discussed, which allows one to include friction effects at reasonable cost for large structural systems such as the Space Shuttle. Data are presented to indicate the possible impact of transient friction loads to the payload designer for the Space Shuttle. Transient response solution data are also included, which compare solutions without friction forces and those with friction forces for payloads mounted in the Space Shuttle cargo bay. These data indicate that payload components can be sensitive to friction induced loads.

False Operation of Static Random Access Memory Cells under Alternating Current Power Supply Voltage Variation

Science.gov (United States)

Sawada, Takuya; Takata, Hidehiro; Nii, Koji; Nagata, Makoto

2013-04-01

Static random access memory (SRAM) cores exhibit susceptibility against power supply voltage variation. False operation is investigated among SRAM cells under sinusoidal voltage variation on power lines introduced by direct RF power injection. A standard SRAM core of 16 kbyte in a 90 nm 1.5 V technology is diagnosed with built-in self test and on-die noise monitor techniques. The sensitivity of bit error rate is shown to be high against the frequency of injected voltage variation, while it is not greatly influenced by the difference in frequency and phase against SRAM clocking. It is also observed that the distribution of false bits is substantially random in a cell array.

On the geometric phenomenology of static friction.

Science.gov (United States)

Ghosh, Shankar; Merin, A P; Nitsure, Nitin

2017-09-06

In this note we introduce a hierarchy of phase spaces for static friction, which give a graphical way to systematically quantify the directional dependence in static friction via subregions of the phase spaces. We experimentally plot these subregions to obtain phenomenological descriptions for static friction in various examples where the macroscopic shape of the object affects the frictional response. The phase spaces have the universal property that for any experiment in which a given object is put on a substrate fashioned from a chosen material with a specified nature of contact, the frictional behaviour can be read off from a uniquely determined classifying map on the control space of the experiment which takes values in the appropriate phase space.

Static length changes of cochlear outer hair cells can tune low-frequency hearing.

Directory of Open Access Journals (Sweden)

Nikola Ciganović

2018-01-01

Full Text Available The cochlea not only transduces sound-induced vibration into neural spikes, it also amplifies weak sound to boost its detection. Actuators of this active process are sensory outer hair cells in the organ of Corti, whereas the inner hair cells transduce the resulting motion into electric signals that propagate via the auditory nerve to the brain. However, how the outer hair cells modulate the stimulus to the inner hair cells remains unclear. Here, we combine theoretical modeling and experimental measurements near the cochlear apex to study the way in which length changes of the outer hair cells deform the organ of Corti. We develop a geometry-based kinematic model of the apical organ of Corti that reproduces salient, yet counter-intuitive features of the organ's motion. Our analysis further uncovers a mechanism by which a static length change of the outer hair cells can sensitively tune the signal transmitted to the sensory inner hair cells. When the outer hair cells are in an elongated state, stimulation of inner hair cells is largely inhibited, whereas outer hair cell contraction leads to a substantial enhancement of sound-evoked motion near the hair bundles. This novel mechanism for regulating the sensitivity of the hearing organ applies to the low frequencies that are most important for the perception of speech and music. We suggest that the proposed mechanism might underlie frequency discrimination at low auditory frequencies, as well as our ability to selectively attend auditory signals in noisy surroundings.

An Optimization Mechanism Intended for Static Power Reduction Using Dual-thTechnique

Directory of Open Access Journals (Sweden)

Rodolfo P. Santos

2012-01-01

Full Text Available Power consumption reduction is a challenge nowadays. Techniques for dynamic and static power minimization have been proposed, but most of them are very time consuming. This work proposes an algorithm for reducing static power, which can be perfectly inserted in the conventional design flow for integrated systems considering an open source environment (open access infrastructure. The proposed approach, based on a Dual-Threshold technique, replaces part of the cells of the circuit by cells with a higher threshold voltage without resulting in timing violations in the circuit. The decision to replace a cell is based on timing estimates of the circuit modeling with the cell replacement, before it is actually replaced. The fact that only some cells are replaced every iteration results in a reduction of the runtime of the algorithm. Additionally, results showed a reduction in static power up to 39.28%, when applying the proposed approach in the ISCAS85 benchmark circuits.

Pre-operative radiotherapy in soft tissue tumors: Assessment of response by static post-contrast MR imaging compared to histopathology

International Nuclear Information System (INIS)

Einarsdottir, H.; Wejde, J.; Bauer, H.C.F.

2000-01-01

To evaluate if static post-contrast MR imaging was adequate to assess tumor viability after pre-operative radiotherapy in soft tissue sarcoma. Post-contrast MR imaging of 36 soft tissue sarcomas performed 0 - 54 days (median 13 days) after pre-operative radiotherapy, were retrospectively reviewed and compared to post-operative histopathology reports. The contrast enhancement of the tumor was visually graded as minor, moderate or extensive. From the post-operative histopathology reports, three types of tumor response to radiotherapy were defined: Poor, intermediate or good. The size of the tumors before and after radiation was compared. Even if most viable tumors enhanced more than non-viable tumors, there was major overlapping and significant contrast enhancement could be seen in tumors where histopathological examination revealed no viable tumor tissue. Based on histopathology, there were 12 good responders; 8 of these showed minor, 3 moderate and 1 extensive contrast enhancement on MR imaging. Sixteen tumors had an intermediate response; 3 showed minor, 8 moderate and 5 extensive enhancement. Eight tumors had poor response; none showed minor enhancement, 3 moderate and 5 extensive enhancement. Both increase and Decrease in tumor size was seen in lesions with a good therapy response. Static post-contrast MR imaging cannot reliably assess tumor viability after pre-operative radiotherapy in soft tissue sarcoma. In tumors with no viable tumor tissue, moderate and extensive contrast enhancement can be seen

T cell resistance to activation by dendritic cells requires long-term culture in simulated microgravity

Science.gov (United States)

Bradley, Jillian H.; Stein, Rachel; Randolph, Brad; Molina, Emily; Arnold, Jennifer P.; Gregg, Randal K.

2017-11-01

Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines. Finally, the effector T cells acquire the weaponry needed to destroy microbial invaders and tumors. Studies conducted on T cells during spaceflight, or using Earth-based culture systems, have shown reduced production of cytokines, proliferation and effector functions as compared to controls. This may account for the cases of viral reactivation events and opportunistic infections associated with astronauts of numerous missions. This work has largely been based upon the outcome of T cell activation by stimulatory factors that target select T cell signaling pathways rather than the complex, signaling events related to the natural process of antigen presentation by DC. This study tested the response of an ovalbumin peptide-specific T cell line, OT-II TCH, to activation by DC when the T cells were cultured 24-120 h in a simulated microgravity (SMG) environment generated by a rotary cell culture system. Following 72 h culture of T cells in SMG (SMG-T) or control static (Static-T) conditions, IL-2 production by the T cells was reduced in SMG-T cells compared to Static-T cells upon stimulation by phorbol 12-myristate 13-acetate (PMA) and ionomycin. However, when the SMG-T cells were stimulated with DC and peptide, IL-2 was significantly increased compared to Static-T cells. Such enhanced IL-2 production by SMG-T cells peaked at 72 h SMG culture time and decreased thereafter. When

PEBBLES Simulation of Static Friction and New Static Friction Benchmark

International Nuclear Information System (INIS)

Cogliati, Joshua J.; Ougouag, Abderrafi M.

2010-01-01

Pebble bed reactors contain large numbers of spherical fuel elements arranged randomly. Determining the motion and location of these fuel elements is required for calculating certain parameters of pebble bed reactor operation. This paper documents the PEBBLES static friction model. This model uses a three dimensional differential static friction approximation extended from the two dimensional Cundall and Strack model. The derivation of determining the rotational transformation of pebble to pebble static friction force is provided. A new implementation for a differential rotation method for pebble to container static friction force has been created. Previous published methods are insufficient for pebble bed reactor geometries. A new analytical static friction benchmark is documented that can be used to verify key static friction simulation parameters. This benchmark is based on determining the exact pebble to pebble and pebble to container static friction coefficients required to maintain a stable five sphere pyramid.

The linear and nonlinear response of infinite periodic systems to static and/or dynamic electric fields. Implementation in CRYSTAL code

Energy Technology Data Exchange (ETDEWEB)

Kirtman, Bernard [Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States); Springborg, Michael [Physical and Theoretical Chemistry, University of Saarland, 66123 Saarbrücken (Germany); Rérat, Michel [Equipe de Chimie Physique, IPREM UMR5254, Université de Pau et des Pays de l' Adour, 64000 Pau (France); Ferrero, Mauro; Lacivita, Valentina; Dovesi, Roberto [Departimeno di Chimica, IFM, Università di Torino and NIS - Nanostructure Interfaces and Surfaces - Centre of Excellence, Via P. Giuria 7, 10125 Torino (Italy); Orlando, Roberto [Departimento di Scienze e Tecnologie Avanzati, Università del Piemonte Orientale, Viale T. Michel 11, 15121 Alessandria (Italy)

2015-01-22

An implementation of the vector potential approach (VPA) for treating the response of infinite periodic systems to static and dynamic electric fields has been initiated within the CRYSTAL code. The VPA method is based on the solution of a time-dependent Hartree-Fock or Kohn-Sham equation for the crystal orbitals wherein the usual scalar potential, that describes interaction with the field, is replaced by the vector potential. This equation may be solved either by perturbation theory or by finite field methods. With some modification all the computational procedures of molecular ab initio quantum chemistry can be adapted for periodic systems. Accessible properties include the linear and nonlinear responses of both the nuclei and the electrons. The programming of static field pure electronic (hyper)polarizabilities has been successfully tested. Dynamic electronic (hyper)polarizabilities, as well as infrared and Raman intensities, are in progress while the addition of finite fields for calculation of vibrational (hyper)polarizabilities, through nuclear relaxation procedures, will begin shortly.

An easily implemented static condensation method for structural sensitivity analysis

Science.gov (United States)

Gangadharan, S. N.; Haftka, R. T.; Nikolaidis, E.

1990-01-01

A black-box approach to static condensation for sensitivity analysis is presented with illustrative examples of a cube and a car structure. The sensitivity of the structural response with respect to joint stiffness parameter is calculated using the direct method, forward-difference, and central-difference schemes. The efficiency of the various methods for identifying joint stiffness parameters from measured static deflections of these structures is compared. The results indicate that the use of static condensation can reduce computation times significantly and the black-box approach is only slightly less efficient than the standard implementation of static condensation. The ease of implementation of the black-box approach recommends it for use with general-purpose finite element codes that do not have a built-in facility for static condensation.

Static timing analysis for nanometer designs

CERN Document Server

Bhasker, J

2009-01-01

Covers topics such as cell timing and power modeling; interconnect modeling and analysis, delay calculation, crosstalk, noise and the chip timing verification using static timing analysis. For each of these topics, this book provides a theoretical background as well as detailed examples to elaborate the concepts.

Development of a static feed water electrolysis system

Science.gov (United States)

Schubert, F. H.; Lantz, J. B.; Hallick, T. M.

1982-01-01

A one person level oxygen generation subsystem was developed and production of the one person oxygen metabolic requirements, 0.82 kg, per day was demonstrated without the need for condenser/separators or electrolyte pumps. During 650 hours of shakedown, design verification, and endurance testing, cell voltages averaged 1.62 V at 206 mA/sq cm and at average operating temperature as low as 326 K, virtually corresponding to the state of the art performance previously established for single cells. This high efficiency and low waste heat generation prevented maintenance of the 339 K design temperature without supplemental heating. Improved water electrolysis cell frames were designed, new injection molds were fabricated, and a series of frames was molded. A modified three fluid pressure controller was developed and a static feed water electrolysis that requires no electrolyte in the static feed compartment was developed and successfully evaluated.

T cell resistance to activation by dendritic cells requires long-term culture in simulated microgravity.

Science.gov (United States)

Bradley, Jillian H; Stein, Rachel; Randolph, Brad; Molina, Emily; Arnold, Jennifer P; Gregg, Randal K

2017-11-01

Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines. Finally, the effector T cells acquire the weaponry needed to destroy microbial invaders and tumors. Studies conducted on T cells during spaceflight, or using Earth-based culture systems, have shown reduced production of cytokines, proliferation and effector functions as compared to controls. This may account for the cases of viral reactivation events and opportunistic infections associated with astronauts of numerous missions. This work has largely been based upon the outcome of T cell activation by stimulatory factors that target select T cell signaling pathways rather than the complex, signaling events related to the natural process of antigen presentation by DC. This study tested the response of an ovalbumin peptide-specific T cell line, OT-II TCH, to activation by DC when the T cells were cultured 24-120 h in a simulated microgravity (SMG) environment generated by a rotary cell culture system. Following 72 h culture of T cells in SMG (SMG-T) or control static (Static-T) conditions, IL-2 production by the T cells was reduced in SMG-T cells compared to Static-T cells upon stimulation by phorbol 12-myristate 13-acetate (PMA) and ionomycin. However, when the SMG-T cells were stimulated with DC and peptide, IL-2 was significantly increased compared to Static-T cells. Such enhanced IL-2 production by SMG-T cells peaked at 72 h SMG culture time and decreased thereafter

Microenvironment is involved in cellular response to hydrostatic pressures during chondrogenesis of mesenchymal stem cells.

Science.gov (United States)

Ye, Rui; Hao, Jin; Song, Jinlin; Zhao, Zhihe; Fang, Shanbao; Wang, Yating; Li, Juan

2014-06-01

Chondrocytes integrate numerous microenvironmental cues to mount physiologically relevant differentiation responses, and the regulation of mechanical signaling in chondrogenic differentiation is now coming into intensive focus. To facilitate tissue-engineered chondrogenesis by mechanical strategy, a thorough understanding about the interactional roles of chemical factors under mechanical stimuli in regulating chondrogenesis is in great need. Therefore, this study attempts to investigate the interaction of rat MSCs with their microenvironment by imposing dynamic and static hydrostatic pressure through modulating gaseous tension above the culture medium. Under dynamic pressure, chemical parameters (pH, pO2, and pCO2) were kept in homeostasis. In contrast, pH was remarkably reduced due to increased pCO2 under static pressure. MSCs under the dynamically pressured microenvironment exhibited a strong accumulation of GAG within and outside the alginate beads, while cells under the statically pressured environment lost newly synthesized GAG into the medium with a speed higher than its production. In addition, the synergic influence on expression of chondrogenic genes was more persistent under dynamic pressure than that under static pressure. This temporal contrast was similar to that of activation of endogenous TGF-β1. Taken altogether, it indicates that a loading strategy which can keep a homeostatic chemical microenvironment is preferred, since it might sustain the stimulatory effects of mechanical stimuli on chondrogenesis via activation of endogenous TGF-β1. © 2013 Wiley Periodicals, Inc.

Tissue factor-expressing tumor cells can bind to immobilized recombinant tissue factor pathway inhibitor under static and shear conditions in vitro.

Directory of Open Access Journals (Sweden)

Sara P Y Che

Full Text Available Mammary tumors and malignant breast cancer cell lines over-express the coagulation factor, tissue factor (TF. High expression of TF is associated with a poor prognosis in breast cancer. Tissue factor pathway inhibitor (TFPI, the endogenous inhibitor of TF, is constitutively expressed on the endothelium. We hypothesized that TF-expressing tumor cells can bind to immobilized recombinant TFPI, leading to arrest of the tumor cells under shear in vitro. We evaluated the adhesion of breast cancer cells to immobilized TFPI under static and shear conditions (0.35 - 1.3 dyn/cm2. We found that high-TF-expressing breast cancer cells, MDA-MB-231 (with a TF density of 460,000/cell, but not low TF-expressing MCF-7 (with a TF density of 1,400/cell, adhered to recombinant TFPI, under static and shear conditions. Adhesion of MDA-MB-231 cells to TFPI required activated factor VII (FVIIa, but not FX, and was inhibited by a factor VIIa-blocking anti-TF antibody. Under shear, adhesion to TFPI was dependent on the TFPI-coating concentration, FVIIa concentration and shear stress, with no observed adhesion at shear stresses greater than 1.0 dyn/cm2. This is the first study showing that TF-expressing tumor cells can be captured by immobilized TFPI, a ligand constitutively expressed on the endothelium, under low shear in vitro. Based on our results, we hypothesize that TFPI could be a novel ligand mediating the arrest of TF-expressing tumor cells in high TFPI-expressing vessels under conditions of low shear during metastasis.

Study of a photovoltaic cell to silicon tri grain under illumination in static mode: determination of the parameters of recombination

International Nuclear Information System (INIS)

ZERBO Issa

2000-01-01

A study of the photovoltaic cell to silicon tri grain under illumination functioning at a static normal rate is presented. The determination of the parameters of recombination relies on the analysis of the photo-answer of the photovoltaic cell. The length of diffusion L, the speeds of recombination of minority carriers and respectively on the surface of the junction and with the back face of the base of the photovoltaic cell are extracted thanks to the measurement from the from short-circuit electricity and the tension from open circuit [fr

Mammals' response and adaptation to static magnetic fields as a nonspecific stressor

Science.gov (United States)

Nakagawa, Masayoshi

1990-06-01

Biological effects of static magnetic fields are still unclear and sometimes contradictory, and it has not been possible to connect this situation directly to some explanations of the mechanisms of the effects of static magnetic fields at the molecular level. Some researchers have pointed out that the process through which animals respond at the whole-body level to static magnetic fields follows the same pattern as the GAS (general adaptation syndrome) described by Selye. This biological or behavioral pattern is considered to be a common process followed by animals which are affected by environmental stimulants; they are depressed first, then surpass the deteriorated conditions and recover their normal conditions, or sometimes overshoot it. When this process is observed with mammals subjected to the magnetic fields, it can be concluded that magnetism has affected the organism. In this paper, the author reviews reports in which magnetic field density and minimum exposure time were determined with certain effects produced under certain conditions, and proposes a regression model for estimating the minimum amount of exposure which produces some effect on mammals.

Calculation of equivalent static loads and its application

International Nuclear Information System (INIS)

Choi, Woo-Seok; Park, K.B.; Park, G.J.

2005-01-01

All the forces in the real world act dynamically on structures. Since dynamic loads are extremely difficult to handle in analysis and design, static loads are usually utilized with dynamic factors. Generally, the dynamic factors are determined from design codes or experience. Therefore, static loads may not give accurate solutions in analysis and design and structural engineers often come up with unreliable solutions. Two different methods are proposed for the transformation of dynamic loads into equivalent static loads (ESLs). One is an analytical method for exact ESLs and the other is an approximation method. The exact ESLs are calculated to generate identical response fields such as displacement and stress with those from dynamic loads at a certain time. Some approximation methods are proposed in engineering applications, which generate similar response fields from dynamic loads. They are divided into the displacement-based approach and the stress-based approach. The process is derived and evaluated mathematically. Standard examples are selected and solved by the proposed method and error analyses are conducted. Applications of the method to structural optimization are discussed

Thermal effects in static friction: thermolubricity.

Science.gov (United States)

Franchini, A; Bortolani, V; Santoro, G; Brigazzi, M

2008-10-01

We present a molecular dynamics analysis of the static friction between two thick slabs. The upper block is formed by N2 molecules and the lower block by Pb atoms. We study the effects of the temperature as well as the effects produced by the structure of the surface of the lower block on the static friction. To put in evidence the temperature effects we will compare the results obtained with the lower block formed by still atoms with those obtained when the atoms are allowed to vibrate (e.g., with phonons). To investigate the importance of the geometry of the surface of the lower block we apply the external force in different directions, with respect to a chosen crystallographic direction of the substrate. We show that the interaction between the lattice dynamics of the two blocks is responsible for the strong dependence of the static friction on the temperature. The lattice dynamics interaction between the two blocks strongly reduces the static friction, with respect to the case of the rigid substrate. This is due to the large momentum transfer between atoms and the N2 molecules which disorders the molecules of the interface layer. A further disorder is introduced by the temperature. We perform calculations at T = 20K which is a temperature below the melting, which for our slab is at 50K . We found that because of the disorder the static friction becomes independent of the direction of the external applied force. The very low value of the static friction seems to indicate that we are in a regime of thermolubricity similar to that observed in dynamical friction.

Investigation of Quasi-Static Indentation Response of Inkjet Printed Sandwich Structures under Various Indenter Geometries

Science.gov (United States)

Dikshit, Vishwesh; Nagalingam, Arun Prasanth; Yap, Yee Ling; Sing, Swee Leong; Yeong, Wai Yee; Wei, Jun

2017-01-01

The objective of this investigation was to determine the quasi-static indentation response and failure mode in three-dimensional (3D) printed trapezoidal core structures, and to characterize the energy absorbed by the structures. In this work, the trapezoidal sandwich structure was designed in the following two ways. Firstly, the trapezoidal core along with its facesheet was 3D printed as a single element comprising a single material for both core and facesheet (type A); Secondly, the trapezoidal core along with facesheet was 3D printed, but with variation in facesheet materials (type B). Quasi-static indentation was carried out using three different indenters, namely standard hemispherical, conical, and flat indenters. Acoustic emission (AE) technique was used to capture brittle cracking in the specimens during indentation. The major failure modes were found to be brittle failure and quasi-brittle fractures. The measured indentation energy was at a maximum when using a conical indenter at 9.40 J and 9.66 J and was at a minimum when using a hemispherical indenter at 6.87 J and 8.82 J for type A and type B series specimens respectively. The observed maximum indenter displacements at failure were the effect of material variations and composite configurations in the facesheet. PMID:28772649

Intrinsic rippling enhances static non-reciprocity in a graphene metamaterial.

Science.gov (United States)

Ho, Duc Tam; Park, Harold S; Kim, Sung Youb

2018-01-18

In mechanical systems, Maxwell-Betti reciprocity means that the displacement at point B in response to a force at point A is the same as the displacement at point A in response to the same force applied at point B. Because the notion of reciprocity is general, fundamental, and is operant for other physical systems like electromagnetics, acoustics, and optics, there is significant interest in understanding systems that are not reciprocal, or exhibit non-reciprocity. However, most studies on non-reciprocity have occurred in bulk-scale structures for dynamic problems involving time reversal symmetry. As a result, little is known about the mechanisms governing static non-reciprocal responses, particularly in atomically-thin two-dimensional materials like graphene. Here, we use classical atomistic simulations to demonstrate that out-of-plane ripples, which are intrinsic to graphene, enable significant, multiple orders of magnitude enhancements in the statically non-reciprocal response of graphene metamaterials. Specifically, we find that a striking interplay between the ripples and the stress fields that are induced in the metamaterials due to their geometry impacts the displacements that are transmitted by the metamaterial, thus leading to a significantly enhanced static non-reciprocal response. This study thus demonstrates the potential of two-dimensional mechanical metamaterials for symmetry-breaking applications.

Static friction between silicon nanowires and elastomeric substrates.

Science.gov (United States)

Qin, Qingquan; Zhu, Yong

2011-09-27

This paper reports the first direct measurements of static friction force and interfacial shear strength between silicon (Si) nanowires (NWs) and poly(dimethylsiloxane) (PDMS). A micromanipulator is used to manipulate and deform the NWs under a high-magnification optical microscope in real time. The static friction force is measured based on "the most-bent state" of the NWs. The static friction and interface shear strength are found to depend on the ultraviolet/ozone (UVO) treatment of PDMS. The shear strength starts at 0.30 MPa without UVO treatment, increases rapidly up to 10.57 MPa at 60 min of treatment and decreases for longer treatment. Water contact angle measurements suggest that the UVO-induced hydrophobic-to-hydrophilic conversion of PDMS surface is responsible for the increase in the static friction, while the hydrophobic recovery effect contributes to the decrease. The static friction between NWs and PDMS is of critical relevance to many device applications of NWs including NW-based flexible/stretchable electronics, NW assembly and nanocomposites (e.g., supercapacitors). Our results will enable quantitative interface design and control for such applications. © 2011 American Chemical Society

NKT Cell Responses to B Cell Lymphoma.

Science.gov (United States)

Li, Junxin; Sun, Wenji; Subrahmanyam, Priyanka B; Page, Carly; Younger, Kenisha M; Tiper, Irina V; Frieman, Matthew; Kimball, Amy S; Webb, Tonya J

2014-06-01

Natural killer T (NKT) cells are a unique subset of CD1d-restricted T lymphocytes that express characteristics of both T cells and natural killer cells. NKT cells mediate tumor immune-surveillance; however, NKT cells are numerically reduced and functionally impaired in lymphoma patients. Many hematologic malignancies express CD1d molecules and co-stimulatory proteins needed to induce anti-tumor immunity by NKT cells, yet most tumors are poorly immunogenic. In this study, we sought to investigate NKT cell responses to B cell lymphoma. In the presence of exogenous antigen, both mouse and human NKT cell lines produce cytokines following stimulation by B cell lymphoma lines. NKT cell populations were examined ex vivo in mouse models of spontaneous B cell lymphoma, and it was found that during early stages, NKT cell responses were enhanced in lymphoma-bearing animals compared to disease-free animals. In contrast, in lymphoma-bearing animals with splenomegaly and lymphadenopathy, NKT cells were functionally impaired. In a mouse model of blastoid variant mantle cell lymphoma, treatment of tumor-bearing mice with a potent NKT cell agonist, α-galactosylceramide (α-GalCer), resulted in a significant decrease in disease pathology. Ex vivo studies demonstrated that NKT cells from α-GalCer treated mice produced IFN-γ following α-GalCer restimulation, unlike NKT cells from vehicle-control treated mice. These data demonstrate an important role for NKT cells in the immune response to an aggressive hematologic malignancy like mantle cell lymphoma.

Fe3O4/BSA particles induce osteogenic differentiation of mesenchymal stem cells under static magnetic field.

Science.gov (United States)

Jiang, Pengfei; Zhang, Yixian; Zhu, Chaonan; Zhang, Wenjing; Mao, Zhengwei; Gao, Changyou

2016-12-01

Differentiation of stem cells is influenced by many factors, yet uptake of the magnetic particles with or without magnetic field is rarely tackled. In this study, iron oxide nanoparticles-loaded bovine serum albumin (BSA) (Fe 3 O 4 /BSA) particles were prepared, which showed a spherical morphology with a diameter below 200 nm, negatively charged surface, and tunable magnetic property. The particles could be internalized into bone marrow mesenchymal stem cells (MSCs), and their release from the cells was significantly retarded under external magnetic field, resulting in almost twice intracellular amount of the particles within 21 d compared to that of the magnetic field free control. Uptake of the Fe 3 O 4 /BSA particles enhanced significantly the osteogenic differentiation of MSCs under a static magnetic field, as evidenced by elevated alkaline phosphatase (ALP) activity, calcium deposition, and expressions of collagen type I and osteocalcin at both mRNA and protein levels. Therefore, uptake of the Fe 3 O 4 /BSA particles brings significant influence on the differentiation of MSCs under magnetic field, and thereby should be paid great attention for practical applications. Differentiation of stem cells is influenced by many factors, yet uptake of the magnetic particles with or without magnetic field is rarely tackled. In this study, iron oxide nanoparticles-loaded bovine serum albumin (BSA) (Fe 3 O 4 /BSA) particles with a diameter below 200nm, negatively charged surface, tunable Fe 3 O 4 content and subsequently adjustable magnetic property were prepared. The particles could be internalized into bone marrow mesenchymal stem cells (MSCs), and their release from the cells was significantly retarded under external magnetic field. Uptake of the Fe 3 O 4 /BSA particles enhanced significantly the osteogenic differentiation of MSCs under a constant static magnetic field, while the magnetic particles and external magnetic field alone do not influence significantly the

Online remote control systems for static and dynamic compression and decompression using diamond anvil cells

International Nuclear Information System (INIS)

Sinogeikin, Stanislav V.; Smith, Jesse S.; Rod, Eric; Lin, Chuanlong; Kenney-Benson, Curtis; Shen, Guoyin

2015-01-01

The ability to remotely control pressure in diamond anvil cells (DACs) in accurate and consistent manner at room temperature, as well as at cryogenic and elevated temperatures, is crucial for effective and reliable operation of a high-pressure synchrotron facility such as High Pressure Collaborative Access Team (HPCAT). Over the last several years, a considerable effort has been made to develop instrumentation for remote and automated pressure control in DACs during synchrotron experiments. We have designed and implemented an array of modular pneumatic (double-diaphragm), mechanical (gearboxes), and piezoelectric devices and their combinations for controlling pressure and compression/decompression rate at various temperature conditions from 4 K in cryostats to several thousand Kelvin in laser-heated DACs. Because HPCAT is a user facility and diamond cells for user experiments are typically provided by users, our development effort has been focused on creating different loading mechanisms and frames for a variety of existing and commonly used diamond cells rather than designing specialized or dedicated diamond cells with various drives. In this paper, we review the available instrumentation for remote static and dynamic pressure control in DACs and show some examples of their applications to high pressure research

Investigation of static and dynamic wetting transitions of UV responsive tunable wetting surfaces

International Nuclear Information System (INIS)

Pant, Reeta; Singha, Subhash; Bandyopadhyay, Aritra; Khare, Krishnacharya

2014-01-01

Ultraviolet (UV) radiation responsive surfaces, with tunable wetting properties, are fabricated by spin casting polystyrene/titania nanocomposite dispersion in tetrahydrofuran on silicon substrates. The prepared samples are found hydrophilic due to the presence of the water miscible solvent. Upon annealing, as the solvent evaporates, samples become superhydrophobic due to presence of hydrophobic polystyrene and formation of nano and micro scale surface roughness due to titania nanoparticles. Effect of different annealing temperatures and time on resulting wettability is investigated. Photocatalytic property of titania is exploited to make transition from superhydrophobic to hydrophilic state upon UV exposure. Subsequently, upon annealing again at elevated temperatures for sufficient time, the UV exposed hydrophilic samples recover their superhydrophobicity showing transition from hydrophilic to superhydrophobic state. Detailed static and dynamic study of these reversible transitions, between superhydrophobic and hydrophilic states, due to UV exposure and annealing is presented in this article.

Auditory cortical neurons are sensitive to static and continuously changing interaural phase cues.

Science.gov (United States)

Reale, R A; Brugge, J F

1990-10-01

1. The interaural-phase-difference (IPD) sensitivity of single neurons in the primary auditory (AI) cortex of the anesthetized cat was studied at stimulus frequencies ranging from 120 to 2,500 Hz. Best frequencies of the 43 AI cells sensitive to IPD ranged from 190 to 2,400 Hz. 2. A static IPD was produced when a pair of low-frequency tone bursts, differing from one another only in starting phase, were presented dichotically. The resulting IPD-sensitivity curves, which plot the number of discharges evoked by the binaural signal as a function of IPD, were deeply modulated circular functions. IPD functions were analyzed for their mean vector length (r) and mean interaural phase (phi). Phase sensitivity was relatively independent of best frequency (BF) but highly dependent on stimulus frequency. Regardless of BF or stimulus frequency within the excitatory response area the majority of cells fired maximally when the ipsilateral tone lagged the contralateral signal and fired least when this interaural-phase relationship was reversed. 3. Sensitivity to continuously changing IPD was studied by delivering to the two ears 3-s tones that differed slightly in frequency, resulting in a binaural beat. Approximately 26% of the cells that showed a sensitivity to static changes in IPD also showed a sensitivity to dynamically changing IPD created by this binaural tonal combination. The discharges were highly periodic and tightly synchronized to a particular phase of the binaural beat cycle. High synchrony can be attributed to the fact that cortical neurons typically respond to an excitatory stimulus with but a single spike that is often precisely timed to stimulus onset. A period histogram, binned on the binaural beat frequency (fb), produced an equivalent IPD-sensitivity function for dynamically changing interaural phase. For neurons sensitive to both static and continuously changing interaural phase there was good correspondence between their static (phi s) and dynamic (phi d

Static capacity of laterally pre-cycled monopiles in dense sand

DEFF Research Database (Denmark)

Nicolai, Giulio; Ibsen, Lars Bo

This work aims to investigate the change in static capacity of monopiles due to cyclic lateral loading. Results from small-scale tests on a monopile model in dense saturated sand are presented. Three series of tests were carried out to study the response of the monopile to different cyclic lateral...... loading conditions. A formulation to predict the change in static capacity is proposed and applied to confirm the tests results....

The effect of static and pulsating magnetic field on immunocompetent cells in blood of hematological patients in nitro

International Nuclear Information System (INIS)

Bessmel'tsev, S.S.; Abdulkadyrov, K.M.; Gonchar, V.A.; Lavrushina, T.S.

2001-01-01

Immunological characteristics were studied in 103 patients with multiple myeloma, acute leukemia, chronic lymphocytic leukemia and non-Hodgkin's disease following in vitro exposure of blood to a low-intensity static field (SF) and alternating field (AF) or pulse magnetic field (PF). In a SF-AF study of multiple myeloma, a 30 min exposure had a positive effect on expression of tumor cells and T-cell markers and stimulated the regulatory function of T-lymphocytes. In acute leukemia, a combined application of the magnetic fields had an effect on the helper activity of the T-lymphocyte subpopulation. The phagocyte activity of leukocytes increased significantly while their digestive ability rose to a moderate degree [ru

Keep away from danger: Dangerous objects in dynamic and static situations

Directory of Open Access Journals (Sweden)

Filomena eAnelli

2013-07-01

Full Text Available Behavioral and neuroscience studies have shown that objects observation evokes specific affordances (i.e., action possibilities and motor responses. Recent findings provide evidence that even dangerous objects can modulate the motor system evoking aversive affordances. This sounds intriguing since so far the majority of behavioral, brain imaging, and transcranial magnetic stimulation studies with painful and dangerous stimuli strictly concerned the domain of pain, excepted for evidence suggesting sensitivity to objects’ affordances when neutral objects are located in participants’ peripersonal space. This study investigates whether the observation of a neutral or dangerous object in a static or dynamic situation differently influences motor responses, and the time-course of the dangerous objects’ processing. In three experiments we manipulated: object dangerousness (neutral vs. dangerous; object category (artifact vs. natural; manual response typology (press vs. release a key; object presentation (Experiment 1: dynamic, Experiments 2 and 3: static; object movement direction (Experiment 1: away vs. toward the participant or size (Experiments 2 and 3: big vs. normal vs. small. The task required participants to decide whether the object was an artifact or a natural object, by pressing or releasing one key. Results showed a facilitation for neutral over dangerous objects in the static situation, probably due to an affordance effect. Instead, in the dynamic condition responses were modulated by the object movement direction, with a dynamic affordance effect of neutral objects and an escape-avoidance effect of dangerous objects (neutral objects were processed faster when they moved toward-approached the participant, whereas dangerous objects were processed faster when they moved away from the participant. Moreover, static stimuli influenced the manual response typology. These data indicate the emergence of dynamic affordance and escaping

Relation between radio-adaptive response and cell to cell communication

International Nuclear Information System (INIS)

Keiichiro Ishii

1996-01-01

Ionizing radiation has been considered to cause severe damages to DNA and do harm to cells in proportion to the dose, however low it might be. In 1984, Wolff et al. showed that human peripheral lymphocytes adapted to the low-dose radiation from 3 H-TdR added in culture medium and became resistant to the subsequent irradiation with high-doses of X-rays. This response, which is called radio-adaptive response, is also induced by X-rays and gamma-rays in human lymphocytes and Chinese hamster V79 cells. However, the mechanisms of and conditions for adaptive responses to radiation have not been clarified. With an objective of clarifying the conditions for adaptive responses of cells to radiation, we examined how the cell to cell communication is involved in the adaptive responses. We irradiated normal human embryo-derived (HE) cells and cancer cells (HeLa) in culture at high density with low-dose X-ray and examined their radio-adaptive responses by measuring the changes in sensitivity to subsequent high-dose X-ray irradiation using the Trypan Blue dye-exclusion test method. We also conducted experiments to examine the effects of Ca 2+ ions and Phorbol 12-Myristate 13-Acetate (TPA) which are supposed to be involved in cell to cell communication. (author)

Self-Testing Static Random-Access Memory

Science.gov (United States)

Chau, Savio; Rennels, David

1991-01-01

Proposed static random-access memory for computer features improved error-detecting and -correcting capabilities. New self-testing scheme provides for detection and correction of errors at any time during normal operation - even while data being written into memory. Faults in equipment causing errors in output data detected by repeatedly testing every memory cell to determine whether it can still store both "one" and "zero", without destroying data stored in memory.

Use of static and ac field techniques for measuring mobility and charge lifetimes of radon progeny with a simple device

International Nuclear Information System (INIS)

Sapra, B.K.; Mayya, Y.S.

1998-01-01

A simple device, based on a modification of the scintillation cell, has been developed for the measurement of radon daughter mobility and charge lifetimes by employing AC and static electric fields. It has a central electrode coated with ZnS and the scintillations are recorded by a PMT unit. The coating is made on the wire, instead of on the inner walls, to improve the relative response of the device with respect to the zero field situation. Radon is drawn into the cell by evacuation techniques. Theoretical formulae, relating the observed count rates to the system parameters and progeny mobilities and charge lifetimes, have been derived under zero field, static and AC field situations. Measurements indicate that the device has very low leak rate (T 1/2 ∼38 days) and the initial environment if maintained for long time. Results of experiments carried out with static and AC fields in most air yielded 218 Po mobilities (1.89 cm 2 /V/s) and charge lifetimes (0.08s) are comparable to those reported in the literature. This demonstrates the feasibility of this technique for future studies with different trace gases. A major advantage of this device as opposed to the conventional spectrometric methods is its simplicity. (author)

From Static Output Feedback to Structured Robust Static Output Feedback: A Survey

OpenAIRE

Sadabadi , Mahdieh ,; Peaucelle , Dimitri

2016-01-01

This paper reviews the vast literature on static output feedback design for linear time-invariant systems including classical results and recent developments. In particular, we focus on static output feedback synthesis with performance specifications, structured static output feedback, and robustness. The paper provides a comprehensive review on existing design approaches including iterative linear matrix inequalities heuristics, linear matrix inequalities with rank constraints, methods with ...

Do Dynamic Compared to Static Facial Expressions of Happiness and Anger Reveal Enhanced Facial Mimicry?

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Krystyna Rymarczyk

Full Text Available Facial mimicry is the spontaneous response to others' facial expressions by mirroring or matching the interaction partner. Recent evidence suggested that mimicry may not be only an automatic reaction but could be dependent on many factors, including social context, type of task in which the participant is engaged, or stimulus properties (dynamic vs static presentation. In the present study, we investigated the impact of dynamic facial expression and sex differences on facial mimicry and judgment of emotional intensity. Electromyography recordings were recorded from the corrugator supercilii, zygomaticus major, and orbicularis oculi muscles during passive observation of static and dynamic images of happiness and anger. The ratings of the emotional intensity of facial expressions were also analysed. As predicted, dynamic expressions were rated as more intense than static ones. Compared to static images, dynamic displays of happiness also evoked stronger activity in the zygomaticus major and orbicularis oculi, suggesting that subjects experienced positive emotion. No muscles showed mimicry activity in response to angry faces. Moreover, we found that women exhibited greater zygomaticus major muscle activity in response to dynamic happiness stimuli than static stimuli. Our data support the hypothesis that people mimic positive emotions and confirm the importance of dynamic stimuli in some emotional processing.

Vitamins and glucose metabolism: The role of static magnetic fields.

Science.gov (United States)

Lahbib, Aïda; Ghodbane, Soumaya; Sakly, Mohsen; Abdelmelek, Hafedh

2014-12-01

This review focuses on our own data and other data from the literature of static magnetic fields (SMF) bioeffects and vitamins and glucose metabolism. Three main areas of investigation have been covered: Static magnetic field and glucose metabolism, static magnetic field and vitamins and the role of vitamins on glucose metabolism. Considering these articles comprehensively, the conclusions are as follows: The primary cause of changes in cells after incubation in external SMF is disruption of free radical metabolism and elevation of their concentration. Such disruption causes oxidative stress leading to an unsteadiness of glucose level and insulin release. Moreover, based on available data, it was concluded that exposure to SMF alters plasma levels of vitamin A, C, D and E; these parameters can take part in disorder of glucose homeostasis and insulin release.

Technology advancement of the static feed water electrolysis process

Science.gov (United States)

Schubert, F. H.; Wynveen, R. A.

1977-01-01

A program to advance the technology of oxygen- and hydrogen-generating subsystems based on water electrolysis was studied. Major emphasis was placed on static feed water electrolysis, a concept characterized by low power consumption and high intrinsic reliability. The static feed based oxygen generation subsystem consists basically of three subassemblies: (1) a combined water electrolysis and product gas dehumidifier module; (2) a product gas pressure controller and; (3) a cyclically filled water feed tank. Development activities were completed at the subsystem as well as at the component level. An extensive test program including single cell, subsystem and integrated system testing was completed with the required test support accessories designed, fabricated, and assembled. Mini-product assurance activities were included throughout all phases of program activities. An extensive number of supporting technology studies were conducted to advance the technology base of the static feed water electrolysis process and to resolve problems.

Formula for Forced Vibration Analysis of Structures Using Static ...

African Journals Online (AJOL)

Some methods of dynamic analysis are based on using static factored response ... on a false assumption of direct linear variation in the stress-displacement relationship. Based on the flexible frame model and stiffness formulation a formula for ...

VLE measurements using a static cell vapor phase manual sampling method accompanied with an empirical data consistency test

International Nuclear Information System (INIS)

Freitag, Joerg; Kosuge, Hitoshi; Schmelzer, Juergen P.; Kato, Satoru

2015-01-01

Highlights: • We use a new, simple static cell vapor phase manual sampling method (SCVMS) for VLE (x, y, T) measurement. • The method is applied to non-azeotropic, asymmetric and two-liquid phase forming azeotropic binaries. • The method is approved by a data consistency test, i.e., a plot of the polarity exclusion factor vs. pressure. • The consistency test reveals that with the new SCVMS method accurate VLE near ambient temperature can be measured. • Moreover, the consistency test approves that the effect of air in the SCVMS system is negligible. - Abstract: A new static cell vapor phase manual sampling (SCVMS) method is used for the simple measurement of constant temperature x, y (vapor + liquid) equilibria (VLE). The method was applied to the VLE measurements of the (methanol + water) binary at T/K = (283.2, 298.2, 308.2 and 322.9), asymmetric (acetone + 1-butanol) binary at T/K = (283.2, 295.2, 308.2 and 324.2) and two-liquid phase forming azeotropic (water + 1-butanol) binary at T/K = (283.2 and 298.2). The accuracy of the experimental data was approved by a data consistency test, that is, an empirical plot of the polarity exclusion factor, β, vs. the system pressure, P. The SCVMS data are accurate, because the VLE data converge to the same lnβ vs. lnP straight line determined from conventional distillation-still method and a headspace gas chromatography method

Flux intensification during microfiltration of distillery stillage using a kenics static mixer

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Vasić Vesna M.

2017-01-01

Full Text Available The present work studies the effect of operating parameters (pH, feed flow rate, and transmembrane pressure on microfiltration of distillery stillage. Experiments were conducted in the presence of a Kenics static mixer as a turbulence promoter, and its influence on the flux improvement and specific energy consumption was examined. Response surface methodology was used to investigate the effect of selected factors on microfiltration performances. The results showed that response surface methodology is an appropriate model for mathematical presentation of the process. It was found that the use of a static mixer is justified at the feed flow rates higher than 100 L/h. In contrast, the use of a static mixer at low values of feed flow rate and transmembrane pressure has no justification from an economic point of view. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31002

Study of the effect of static/dynamic Coulomb friction variation at the tape-head interface of a spacecraft tape recorder by non-linear time response simulation

Science.gov (United States)

Mukhopadhyay, A. K.

1978-01-01

A description is presented of six simulation cases investigating the effect of the variation of static-dynamic Coulomb friction on servo system stability/performance. The upper and lower levels of dynamic Coulomb friction which allowed operation within requirements were determined roughly to be three times and 50% respectively of nominal values considered in a table. A useful application for the nonlinear time response simulation is the sensitivity analysis of final hardware design with respect to such system parameters as cannot be varied realistically or easily in the actual hardware. Parameters of the static/dynamic Coulomb friction fall in this category.

Static electricity: A literature review

Science.gov (United States)

Crow, Rita M.

1991-11-01

The major concern with static electricity is its discharging in a flammable atmosphere which can explode and cause a fire. Textile materials can have their electrical resistivity decreased by the addition of antistatic finishes, imbedding conductive particles into the fibres or by adding metal fibers to the yarns. The test methods used in the studies of static electricity include measuring the static properties of materials, of clothed persons, and of the ignition energy of flammable gases. Surveys have shown that there is sparse evidence for fires definitively being caused by static electricity. However, the 'worst-case' philosophy has been adopted and a static electricity safety code is described, including correct grounding procedures and the wearing of anti-static clothing and footwear.

An Abbreviated Protocol for In Vitro Generation of Functional Human Embryonic Stem Cell-Derived Beta-Like Cells

DEFF Research Database (Denmark)

Massumi, Mohammad; Pourasgari, Farzaneh; Nalla, Amarnadh

2016-01-01

developed an abbreviated five-stage protocol (25-30 days) to generate human Embryonic Stem Cell-Derived Beta-like Cells (ES-DBCs). We showed that Geltrex, as an extracellular matrix, could support the generation of ES-DBCs more efficiently than that of the previously described culture systems......The ability to yield glucose-responsive pancreatic beta-cells from human pluripotent stem cells in vitro will facilitate the development of the cell replacement therapies for the treatment of Type 1 Diabetes. Here, through the sequential in vitro targeting of selected signaling pathways, we have...... positive cells, 1% insulin and glucagon positive cells and 30% insulin and NKX6.1 co-expressing cells. Functionally, ES-DBCs were responsive to high glucose in static incubation and perifusion studies, and could secrete insulin in response to successive glucose stimulations. Mitochondrial metabolic flux...

Suppression of pro-inflammatory T-cell responses by human mesothelial cells.

Science.gov (United States)

Lin, Chan-Yu; Kift-Morgan, Ann; Moser, Bernhard; Topley, Nicholas; Eberl, Matthias

2013-07-01

Human γδ T cells reactive to the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP) contribute to acute inflammatory responses. We have previously shown that peritoneal dialysis (PD)-associated infections with HMB-PP producing bacteria are characterized by locally elevated γδ T-cell frequencies and poorer clinical outcome compared with HMB-PP negative infections, implying that γδ T cells may be of diagnostic, prognostic and therapeutic value in acute disease. The regulation by local tissue cells of these potentially detrimental γδ T-cell responses remains to be investigated. Freshly isolated γδ or αβ T cells were cultured with primary mesothelial cells derived from omental tissue, or with mesothelial cell-conditioned medium. Stimulation of cytokine production and proliferation by peripheral T cells in response to HMB-PP or CD3/CD28 beads was assessed by flow cytometry. Resting mesothelial cells were potent suppressors of pro-inflammatory γδ T cells as well as CD4+ and CD8+ αβ T cells. The suppression of γδ T-cell responses was mediated through soluble factors released by primary mesothelial cells and could be counteracted by SB-431542, a selective inhibitor of TGF-β and activin signalling. Recombinant TGF-β1 but not activin-A mimicked the mesothelial cell-mediated suppression of γδ T-cell responses to HMB-PP. The present findings indicate an important regulatory function of mesothelial cells in the peritoneal cavity by dampening pro-inflammatory T-cell responses, which may help preserve the tissue integrity of the peritoneal membrane in the steady state and possibly during the resolution of acute inflammation.

Factors Released from Endothelial Cells Exposed to Flow Impact Adhesion, Proliferation, and Fate Choice in the Adult Neural Stem Cell Lineage.

Science.gov (United States)

Dumont, Courtney M; Piselli, Jennifer M; Kazi, Nadeem; Bowman, Evan; Li, Guoyun; Linhardt, Robert J; Temple, Sally; Dai, Guohao; Thompson, Deanna M

2017-08-15

The microvasculature within the neural stem cell (NSC) niche promotes self-renewal and regulates lineage progression. Previous work identified endothelial-produced soluble factors as key regulators of neural progenitor cell (NPC) fate and proliferation; however, endothelial cells (ECs) are sensitive to local hemodynamics, and the effect of this key physiological process has not been defined. In this study, we evaluated adult mouse NPC response to soluble factors isolated from static or dynamic (flow) EC cultures. Endothelial factors generated under dynamic conditions significantly increased neuronal differentiation, while those released under static conditions stimulated oligodendrocyte differentiation. Flow increases EC release of neurogenic factors and of heparin sulfate glycosaminoglycans that increase their bioactivity, likely underlying the enhanced neuronal differentiation. Additionally, endothelial factors, especially from static conditions, promoted adherent growth. Together, our data suggest that blood flow may impact proliferation, adhesion, and the neuron-glial fate choice of adult NPCs, with implications for diseases and aging that reduce flow.

DNA-Nanotechnology-Enabled Chiral Plasmonics: From Static to Dynamic.

Science.gov (United States)

Zhou, Chao; Duan, Xiaoyang; Liu, Na

2017-12-19

The development of DNA nanotechnology, especially the advent of DNA origami, has made DNA ideally suited to construct nanostructures with unprecedented complexity and arbitrariness. As a fully addressable platform, DNA origami can be used to organize discrete entities in space through DNA hybridization with nanometer accuracy. Among a variety of functionalized particles, metal nanoparticles such as gold nanoparticles (AuNPs) feature an important pathway to endow DNA-origami-assembled nanostructures with tailored optical functionalities. When metal particles are placed in close proximity, their particle plasmons, i.e., collective oscillations of conduction electrons, can be coupled together, giving rise to a wealth of interesting optical phenomena. Nevertheless, characterization methods that can read out the optical responses from plasmonic nanostructures composed of small metal particles, and especially can optically distinguish in situ their minute conformation changes, are very few. Circular dichroism (CD) spectroscopy has proven to be a successful means to overcome these challenges because of its high sensitivity in discrimination of three-dimensional conformation changes. In this Account, we discuss a variety of static and dynamic chiral plasmonic nanostructures enabled by DNA nanotechnology. In the category of static plasmonic systems, we first show chiral plasmonic nanostructures based on spherical AuNPs, including plasmonic helices, toroids, and tetramers. To enhance the CD responses, anisotropic gold nanorods with larger extinction coefficients are utilized to create chiral plasmonic crosses and helical superstructures. Next, we highlight the inevitable evolution from static to dynamic plasmonic systems along with the fast development of this interdisciplinary field. Several dynamic plasmonic systems are reviewed according to their working mechanisms. We first elucidate a reconfigurable plasmonic cross structure that can execute DNA-regulated conformational

Orienting Paramecium with intense static magnetic fields

Science.gov (United States)

Valles, James M., Jr.; Guevorkian, Karine; Quindel, Carl

2004-03-01

Recent experiments on cell division suggest the application of intense static magnetic fields as a novel tool for the manipulation of biological systems [1]. The magnetic field appears to couple to the intrinsic anisotropies in the diamagnetic components of the cells. Here, we present measurements of the intrinsic average diamagnetic anisotropy of the whole single celled ciliate, Paramecium Caudatum. Magnetic fields, 2.5 T Paramecium Caudatum that were suspended in a density matched medium. The organisms align with their long axis parallel to the applied magnetic field. Their intrinsic diamagnetic anisotropy is 3x10-11 in cgs units. We will discuss the implications of these results for employing magnetic fields to probe the behavior of swimming Paramecium. [1] J. M. Valles, Jr. et al., Expt. Cell Res.274, 112-118 (2002).

Convolutional Sparse Coding for Static and Dynamic Images Analysis

Directory of Open Access Journals (Sweden)

B. A. Knyazev

2014-01-01

Full Text Available The objective of this work is to improve performance of static and dynamic objects recognition. For this purpose a new image representation model and a transformation algorithm are proposed. It is examined and illustrated that limitations of previous methods make it difficult to achieve this objective. Static images, specifically handwritten digits of the widely used MNIST dataset, are the primary focus of this work. Nevertheless, preliminary qualitative results of image sequences analysis based on the suggested model are presented.A general analytical form of the Gabor function, often employed to generate filters, is described and discussed. In this research, this description is required for computing parameters of responses returned by our algorithm. The recursive convolution operator is introduced, which allows extracting free shape features of visual objects. The developed parametric representation model is compared with sparse coding based on energy function minimization.In the experimental part of this work, errors of estimating the parameters of responses are determined. Also, parameters statistics and their correlation coefficients for more than 106 responses extracted from the MNIST dataset are calculated. It is demonstrated that these data correspond well with previous research studies on Gabor filters as well as with works on visual cortex primary cells of mammals, in which similar responses were observed. A comparative test of the developed model with three other approaches is conducted; speed and accuracy scores of handwritten digits classification are presented. A support vector machine with a linear or radial basic function is used for classification of images and their representations while principal component analysis is used in some cases to prepare data beforehand. High accuracy is not attained due to the specific difficulties of combining our model with a support vector machine (a 3.99% error rate. However, another method is

Metabolomic Responses of Guard Cells and Mesophyll Cells to Bicarbonate

Science.gov (United States)

Misra, Biswapriya B.; de Armas, Evaldo; Tong, Zhaohui; Chen, Sixue

2015-01-01

Anthropogenic CO2 presently at 400 ppm is expected to reach 550 ppm in 2050, an increment expected to affect plant growth and productivity. Paired stomatal guard cells (GCs) are the gate-way for water, CO2, and pathogen, while mesophyll cells (MCs) represent the bulk cell-type of green leaves mainly for photosynthesis. We used the two different cell types, i.e., GCs and MCs from canola (Brassica napus) to profile metabolomic changes upon increased CO2 through supplementation with bicarbonate (HCO3 -). Two metabolomics platforms enabled quantification of 268 metabolites in a time-course study to reveal short-term responses. The HCO3 - responsive metabolomes of the cell types differed in their responsiveness. The MCs demonstrated increased amino acids, phenylpropanoids, redox metabolites, auxins and cytokinins, all of which were decreased in GCs in response to HCO3 -. In addition, the GCs showed differential increases of primary C-metabolites, N-metabolites (e.g., purines and amino acids), and defense-responsive pathways (e.g., alkaloids, phenolics, and flavonoids) as compared to the MCs, indicating differential C/N homeostasis in the cell-types. The metabolomics results provide insights into plant responses and crop productivity under future climatic changes where elevated CO2 conditions are to take center-stage. PMID:26641455

Study of the combined action of gamma radiation and static electric fields in human cells; Estudo da acao combinada de radiacao gama e campo eletrico estatico em celulas humanas

Energy Technology Data Exchange (ETDEWEB)

Moron, Michelle Mendes

2008-07-01

The basic principle of radiotherapy is the one of maximizing damage to the tumor, while minimizing it in neighboring health tissues. Several strategies have been worked out aiming at increasing cellular radiosensitivity, and among them is the use of exogenous fields. Our goal in this work is the study in human cells of the effect resulting from the association of irradiation with exposure to exogenous static electric fields. The T47D cell line of breast cancer cells was irradiated with gammas in the 0 - 8 Gy doses range. The corresponding survival curve provided information on the radiosensitivity of this cell line. The rate of cell deaths per Gray in the 0 - 8 Gy range exhibited a maximum at 2 Gy, which corresponds to the most efficient irradiation dose. The viability of this T47D cells exposed to both gamma radiation and 1.250 V/cm static electric field (SEF) was about 12% lower than when only irradiated. The sole exposure of the cells to SEF by 24 and 72 hours didn't induce toxicity. Immunofluorescence runs carried out in irradiated normal MRC5 cell line of human lung fibroblast, without and with exposition to a SEF, have quantified the expression of the y- H2AX histone. The amount of phosphorylated histones was approximately 40% higher after irradiation with 2 Gy plus exposure to a SEF by 1 hour, showing that the electric field negatively interfered in the repairing process of the DNA double strand breaks. The flow cytometry analysis with FACS allowed the investigation of a possible interference of radiation and SEF in the cell distributions among the cellular cycle phases. It was found that in T47D cells treated with 1 and 2 Gy by 24 hours the SEF also negatively interfered in the DNA repairing process, as evidenced by the higher accumulation of cells in the S phase. Therefore, it would be possible to conclude that static and exogenous electric fields are able of negatively interfering in the cellular repair and, presumably, in DNA repair. (author)

Utility of the Static-99 and Static-99R With Latino Sex Offenders.

Science.gov (United States)

Leguízamo, Alejandro; Lee, Seung C; Jeglic, Elizabeth L; Calkins, Cynthia

2017-12-01

The predictive validity of the Static-99 measures with ethnic minorities in the United States has only recently been assessed with mixed results. We assessed the predictive validity of the Static-99 and Static-99R with a sample of Latino sex offenders ( N = 483) as well as with two subsamples (U.S.-born, including Puerto Rico, and non-U.S.-born). The overall sexual recidivism rate was very low (1.9%). Both the Static-99 measures were able to predict sexual recidivism for offenders born in the United States and Puerto Rico, but neither was effective in doing so for other Latino immigrants. Calibration analyses ( N = 303) of the Static-99R were consistent with the literature and provided support for the potential use of the measure with Latinos born in the United States and Puerto Rico. These findings and their implications are discussed as they pertain to the assessment of Latino sex offenders.

Study in static mode of a photovoltaic cell bi facial to crystalline silicon under electric polarization and constant multispectral illumination

International Nuclear Information System (INIS)

ZOUNGRANA Martial

2000-01-01

The theoretical study in static mode of a photovoltaic cell bi facial to silicon under electric polarization and multispectral illumination is presented. Through this study, various expressions of the parameters of recombination have been established as well for an illumination by the face before an illumination by the back face. Curves of variation of the densities of carriers, densities of photocurrent, speeds of recombinations and photo tensions have been traced for the two modes of illumination [fr

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

Directory of Open Access Journals (Sweden)

Irina Alexandra Paun

2018-02-01

Full Text Available We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20–40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis.

Science.gov (United States)

Paun, Irina Alexandra; Popescu, Roxana Cristina; Calin, Bogdan Stefanita; Mustaciosu, Cosmin Catalin; Dinescu, Maria; Luculescu, Catalin Romeo

2018-02-07

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20-40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

Error analysis and prevention of cosmic ion-induced soft errors in static CMOS RAMS

International Nuclear Information System (INIS)

Diehl, S.E.; Ochoa, A. Jr.; Dressendorfer, P.V.; Koga, R.; Kolasinski, W.A.

1982-06-01

Cosmic ray interactions with memory cells are known to cause temporary, random, bit errors in some designs. The sensitivity of polysilicon gate CMOS static RAM designs to logic upset by impinging ions has been studied using computer simulations and experimental heavy ion bombardment. Results of the simulations are confirmed by experimental upset cross-section data. Analytical models have been extended to determine and evaluate design modifications which reduce memory cell sensitivity to cosmic ions. A simple design modification, the addition of decoupling resistance in the feedback path, is shown to produce static RAMs immune to cosmic ray-induced bit errors

Effect of Elastin Digestion on the Quasi-static Tensile Response of Medial Collateral Ligament

Science.gov (United States)

Henninger, Heath B.; Underwood, Clayton J.; Romney, Steven J.; Davis, Grant L.; Weiss, Jeffrey A.

2014-01-01

Elastin is a structural protein that provides resilience to biological tissues. We examined the contributions of elastin to the quasi-static tensile response of porcine medial collateral ligament through targeted disruption of the elastin network with pancreatic elastase. Elastase concentration and treatment time were varied to determine a dose response. Whereas elastin content decreased with increasing elastase concentration and treatment time, the change in peak stress after cyclic loading reached a plateau above 1 U/ml elastase and 6 hr treatment. For specimens treated with 2 U/ml elastase for 6 hr, elastin content decreased approximately 35%. Mean peak tissue strain after cyclic loading (4.8%, p≥0.300), modulus (275 MPa, p≥0.114) and hysteresis (20%, p≥0.553) were unaffected by elastase digestion, but stress decreased significantly after treatment (up to 2 MPa, p≤0.049). Elastin degradation had no effect on failure properties, but tissue lengthened under the same pre-stress. Stiffness in the linear region was unaffected by elastase digestion, suggesting that enzyme treatment did not disrupt collagen. These results demonstrate that elastin primarily functions in the toe region of the stress-strain curve, yet contributes load support in the linear region. The increase in length after elastase digestion suggests that elastin may pre-stress and stabilize collagen crimp in ligaments. PMID:23553827

Human regulatory B cells control the TFH cell response.

Science.gov (United States)

Achour, Achouak; Simon, Quentin; Mohr, Audrey; Séité, Jean-François; Youinou, Pierre; Bendaoud, Boutahar; Ghedira, Ibtissem; Pers, Jacques-Olivier; Jamin, Christophe

2017-07-01

Follicular helper T (T FH ) cells support terminal B-cell differentiation. Human regulatory B (Breg) cells modulate cellular responses, but their control of T FH cell-dependent humoral immune responses is unknown. We sought to assess the role of Breg cells on T FH cell development and function. Human T cells were polyclonally stimulated in the presence of IL-12 and IL-21 to generate T FH cells. They were cocultured with B cells to induce their terminal differentiation. Breg cells were included in these cultures, and their effects were evaluated by using flow cytometry and ELISA. B-cell lymphoma 6, IL-21, inducible costimulator, CXCR5, and programmed cell death protein 1 (PD-1) expressions increased on stimulated human T cells, characterizing T FH cell maturation. In cocultures they differentiated B cells into CD138 + plasma and IgD - CD27 + memory cells and triggered immunoglobulin secretions. Breg cells obtained by Toll-like receptor 9 and CD40 activation of B cells prevented T FH cell development. Added to T FH cell and B-cell cocultures, they inhibited B-cell differentiation, impeded immunoglobulin secretions, and expanded Foxp3 + CXCR5 + PD-1 + follicular regulatory T cells. Breg cells modulated IL-21 receptor expressions on T FH cells and B cells, and their suppressive activities involved CD40, CD80, CD86, and intercellular adhesion molecule interactions and required production of IL-10 and TGF-β. Human Breg cells control T FH cell maturation, expand follicular regulatory T cells, and inhibit the T FH cell-mediated antibody secretion. These novel observations demonstrate a role for the Breg cell in germinal center reactions and suggest that deficient activities might impair the T FH cell-dependent control of humoral immunity and might lead to the development of aberrant autoimmune responses. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

T-cell response in human leishmaniasis

DEFF Research Database (Denmark)

Kharazmi, A; Kemp, K; Ismail, A

1999-01-01

In the present communication we provide evidence for the existence of a Th1/Th2 dichotomy in the T-cell response to Leishmania antigens in human leishmaniasis. Our data suggest that the pattern of IL-4 and IFN-gamma response is polarised in these patients. Lymphocytes from individuals recovered...... from cutaneous leishmaniasis (CL) responded by IFN-gamma production following stimulation with Leishmania antigens whereas cells from patients recovered from visceral leishmaniasis (VL) showed a mixed pattern of IFN-gamma and IL-4 responses. The cells producing these cytokines were predominantly CD4......+. Furthermore, IL-10 plays an important role in the development of post kala azar dermal leishmaniasis (PKDL) from VL. The balance between the parasitic-specific T-cell response plays an important regulatory role in determining the outcome of Leishmania infections in humans....

Quasi-Static Indentation Analysis of Carbon-Fiber Laminates.

Energy Technology Data Exchange (ETDEWEB)

Briggs, Timothy [Sandia National Lab. (SNL-CA), Livermore, CA (United States); English, Shawn Allen [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nelson, Stacy Michelle [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2015-12-01

A series of quasi - static indentation experiments are conducted on carbon fiber reinforced polymer laminates with a systematic variation of thicknesses and fixture boundary conditions. Different deformation mechanisms and their resulting damage mechanisms are activated b y changing the thickn ess and boundary conditions. The quasi - static indentation experiments have been shown to achieve damage mechanisms similar to impact and penetration, however without strain rate effects. The low rate allows for the detailed analysis on the load response. Moreover, interrupted tests allow for the incremental analysis of various damage mechanisms and pr ogressions. The experimentally tested specimens are non - destructively evaluated (NDE) with optical imaging, ultrasonics and computed tomography. The load displacement responses and the NDE are then utilized in numerical simulations for the purpose of model validation and vetting. The accompanying numerical simulation work serves two purposes. First, the results further reveal the time sequence of events and the meaning behind load dro ps not clear from NDE . Second, the simulations demonstrate insufficiencies in the code and can then direct future efforts for development.

Static electromagnetic frequency changers

CERN Document Server

Rozhanskii, L L

1963-01-01

Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

Kinetic parameters evaluation of PWRs using static cell and core calculation codes

International Nuclear Information System (INIS)

Jahanbin, Ali; Malmir, Hessam

2012-01-01

Highlights: ► In this study, we have calculated effective delayed neutron fraction and prompt neutron lifetime in PWRs. ► New software has been developed to link the WIMS, BORGES and CITATION codes in Visual C computer programming language. ► This software is used for calculation of the kinetic parameters in a typical VVER-1000 and NOK Beznau reactor. ► The ratios ((β eff ) i )/((β eff ) core ) , which are the important input data for the reactivity accident analysis, are also calculated. - Abstract: In this paper, evaluation of the kinetic parameters (effective delayed neutron fraction and prompt neutron lifetime) in PWRs, using static cell and core calculation codes, is reported. A new software has been developed to link the WIMS, BORGES and CITATION codes in Visual C computer programming language. Using the WIMS cell calculation code, multigroup microscopic cross-sections and number densities of different materials can be generated in a binary file. By the use of BORGES code, these binary-form cross-sections and number densities are converted to a format readable by the CITATION core calculation code, by which the kinetic parameters can be finally obtained. This software is used for calculation of the kinetic parameters in a typical VVER-1000 and NOK Beznau reactor. The ratios ((β eff ) i )/((β eff ) core ) , which are the important input data for the reactivity accident analysis, are also calculated. Benchmarking of the results against the final safety analysis report (FSAR) of the aforementioned reactors shows very good agreements with these published documents.

Photovoltaic static concentrator analysis

Science.gov (United States)

Almonacid, G.; Luque, A.; Molledo, A. G.

1984-12-01

Ray tracing is the basis of the present analysis of truncated bifacial compound parabolic concentrators filled with a dielectric substance, which are of interest in photovoltaic applications where the bifacial cells allow higher static concentrations to be achieved. Among the figures of merit for this type of concentrator, the directional intercept factor plays a major role and is defined as the ratio of the power of the collector to that at the entry aperture, in a lossless concentrator illuminated by light arriving from a given direction. A procedure for measuring outdoor, full size panels has been developed, and a correction method for avoiding the effect of unwanted diffuse radiation during the measurements is presented.

Static/dynamic fluid-structure interaction analysis for 3-D rotary blade model

International Nuclear Information System (INIS)

Kim, Dong Hyun; Kim, Yu Sung; Kim, Dong Man; Park, Kang Kyun

2009-01-01

In this study, static/dynamic fluid-structure interaction analyses have been conducted for a 3D rotary blade model like a turbo-machinery or wind turbine blade. Advanced computational analysis system based on Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD) has been developed in order to investigate detailed dynamic responses of rotary type models. Fluid domains are modeled using the computational grid system with local grid deforming techniques. Reynolds-averaged Navier-Stokes equations with various turbulence model are solved for unsteady flow problems of the rotating blade model. Detailed static/dynamic responses and instantaneous pressure contours on the blade surfaces considering flow-separation effects are presented to show the multi-physical phenomenon of the rotating blades.

Statics of deformable solids

CERN Document Server

Bisplinghoff, Raymond L; Pian, Theodore HH

2014-01-01

Profusely illustrated exposition of fundamentals of solid mechanics and principles of mechanics, statics, and simple statically indeterminate systems. Covers strain and stress in three-dimensional solids, elementary elasticity, energy principles in solid continuum, and more. 1965 edition.

The frozen face effect: why static photographs may not do you justice.

Science.gov (United States)

Post, Robert B; Haberman, Jason; Iwaki, Lica; Whitney, David

2012-01-01

When a video of someone speaking is paused, the stationary image of the speaker typically appears less flattering than the video, which contained motion. We call this the frozen face effect (FFE). Here we report six experiments intended to quantify this effect and determine its cause. In Experiment 1, video clips of people speaking in naturalistic settings as well as all of the static frames that composed each video were presented, and subjects rated how flattering each stimulus was. The videos were rated to be significantly more flattering than the static images, confirming the FFE. In Experiment 2, videos and static images were inverted, and the videos were again rated as more flattering than the static images. In Experiment 3, a discrimination task measured recognition of the static images that composed each video. Recognition did not correlate with flattery ratings, suggesting that the FFE is not due to better memory for particularly distinct images. In Experiment 4, flattery ratings for groups of static images were compared with those for videos and static images. Ratings for the video stimuli were higher than those for either the group or individual static stimuli, suggesting that the amount of information available is not what produces the FFE. In Experiment 5, videos were presented under four conditions: forward motion, inverted forward motion, reversed motion, and scrambled frame sequence. Flattery ratings for the scrambled videos were significantly lower than those for the other three conditions. In Experiment 6, as in Experiment 2, inverted videos and static images were compared with upright ones, and the response measure was changed to perceived attractiveness. Videos were rated as more attractive than the static images for both upright and inverted stimuli. Overall, the results suggest that the FFE requires continuous, natural motion of faces, is not sensitive to inversion, and is not due to a memory effect.

The Frozen Face Effect: Why static photographs may not do you justice.

Directory of Open Access Journals (Sweden)

Robert ePost

2012-02-01

Full Text Available When a video of someone speaking is paused, the stationary image of the speaker typically appears less flattering than the video, which contained motion. We call this the Frozen Face Effect (FFE. Here we report six experiments intended to quantify this effect and determine its cause. In Experiment 1, video clips of people speaking in naturalistic settings as well as all of the static frames that composed each video were presented, and subjects rated how flattering each stimulus was. The videos were rated to be significantly more flattering than the static images, confirming the FFE. In Experiment 2, videos and static images were inverted, and the videos were again rated as more flattering than the static images. In Experiment 3, a discrimination task measured recognition of the static images that composed each video. Recognition did not correlate with flattery ratings, suggesting that the FFE is not due to better memory for particularly distinct images. In Experiment 4, flattery ratings for groups of static images were compared with those for videos and static images. Ratings for the video stimuli were higher than those for either the group or individual static stimuli, suggesting that the amount of information available is not what produces the FFE. In Experiment 5, videos were presented under four conditions: forward motion, inverted forward motion, reversed motion, and scrambled frame sequence. Flattery ratings for the scrambled videos were significantly lower than those for the other three conditions. In Experiment 6, as in Experiment 2, inverted videos and static images were compared with upright ones, and the response measure was changed to perceived attractiveness. Videos were rated as more attractive than the static images for both upright and inverted stimuli. Overall, the results suggest that the FFE requires continuous, natural motion of faces, is not sensitive to inversion, and is not due to a memory effect.

Terapascal static pressure generation with ultrahigh yield strength nanodiamond.

Science.gov (United States)

Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

2016-07-01

Studies of materials' properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications.

In-Flight Pitot-Static Calibration

Science.gov (United States)

Foster, John V. (Inventor); Cunningham, Kevin (Inventor)

2016-01-01

A GPS-based pitot-static calibration system uses global output-error optimization. High data rate measurements of static and total pressure, ambient air conditions, and GPS-based ground speed measurements are used to compute pitot-static pressure errors over a range of airspeed. System identification methods rapidly compute optimal pressure error models with defined confidence intervals.

Visuo-spatial processing in a dynamic and a static working memory paradigm in schizophrenia

DEFF Research Database (Denmark)

Cocchi, Luca; Schenk, Françoise; Volken, Henri

2007-01-01

patients with schizophrenia and matched controls in a new working memory paradigm involving dynamic (the Ball Flight Task - BFT) or static (the Static Pattern Task - SPT) visual stimuli. In the BFT, the responses of the patients were apparently based on the retention of the last set of segments...... that visuo-spatial working memory can simply be dissociated into visual and spatial sub-components....

Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains

Directory of Open Access Journals (Sweden)

Gao-Xin Wang

2015-01-01

Full Text Available Taking advantage of the structural health monitoring system installed on the steel truss arch girder of Dashengguan Yangtze Bridge, the temperature field data and static strain data are collected and analyzed for the static performance assessment of the bridge. Through analysis, it is found that the static strain changes are mainly caused by temperature field (temperature and temperature difference and train. After the train-induced static strains are removed, the correlation between the remaining static strains and the temperature field shows apparent linear characteristics, which can be mathematically modeled for the description of static performance. Therefore, multivariate linear regression function combined with principal component analysis is introduced to mathematically model the correlation. Furthermore, the residual static strains of mathematical model are adopted as assessment indicator and three kinds of degradation regulations of static performance are obtained after simulation of the residual static strains. Finally, it is concluded that the static performance of Dashengguan Yangtze Bridge was in a good condition during that period.

Role of nesprin-1 in nuclear deformation in endothelial cells under static and uniaxial stretching conditions

International Nuclear Information System (INIS)

Anno, Toshiro; Sakamoto, Naoya; Sato, Masaaki

2012-01-01

Highlights: ► Nesprin-1 knockdown decreases widths of nuclei in ECs under static condition. ► Nuclear strain caused by stretching is increased by nesprin-1 knockdown in ECs. ► We model mechanical interactions of F-actin with the nucleus in stretched cells. ► F-actin bound to nesprin-1 may cause sustainable force transmission to the nucleus. -- Abstract: The linker of nucleus and cytoskeleton (LINC) complex, including nesprin-1, has been suggested to be crucial for many biological processes. Previous studies have shown that mutations in nesprin-1 cause abnormal cellular functions and diseases, possibly because of insufficient force transmission to the nucleus through actin filaments (F-actin) bound to nesprin-1. However, little is known regarding the mechanical interaction between the nucleus and F-actin through nesprin-1. In this study, we examined nuclear deformation behavior in nesprin-1 knocked-down endothelial cells (ECs) subjected to uniaxial stretching by evaluating nuclear strain from lateral cross-sectional images. The widths of nuclei in nesprin-1 knocked-down ECs were smaller than those in wild-type cells. In addition, nuclear strain in nesprin-1 knocked-down cells, which is considered to be compressed by the actin cortical layer, increased compared with that in wild-type cells under stretching condition. These results indicate that nesprin-1 knockdown releases the nucleus from the tension of F-actin bound to the nucleus, thereby increasing allowance for deformation before stretching, and that F-actin bound to the nucleus through nesprin-1 causes sustainable force transmission to the nucleus.

Edge Detection Based On the Characteristic of Primary Visual Cortex Cells

Science.gov (United States)

Zhu, M. M.; Xu, Y. L.; Ma, H. Q.

2018-01-01

Aiming at the problem that it is difficult to balance the accuracy of edge detection and anti-noise performance, and referring to the dynamic and static perceptions of the primary visual cortex (V1) cells, a V1 cell model is established to perform edge detection. A spatiotemporal filter is adopted to simulate the receptive field of V1 simple cells, the model V1 cell is obtained after integrating the responses of simple cells by half-wave rectification and normalization, Then the natural image edge is detected by using static perception of V1 cells. The simulation results show that, the V1 model can basically fit the biological data and has the universality of biology. What’s more, compared with other edge detection operators, the proposed model is more effective and has better robustness

Natural killer cells promote early CD8 T cell responses against cytomegalovirus.

Directory of Open Access Journals (Sweden)

Scott H Robbins

2007-08-01

Full Text Available Understanding the mechanisms that help promote protective immune responses to pathogens is a major challenge in biomedical research and an important goal for the design of innovative therapeutic or vaccination strategies. While natural killer (NK cells can directly contribute to the control of viral replication, whether, and how, they may help orchestrate global antiviral defense is largely unknown. To address this question, we took advantage of the well-defined molecular interactions involved in the recognition of mouse cytomegalovirus (MCMV by NK cells. By using congenic or mutant mice and wild-type versus genetically engineered viruses, we examined the consequences on antiviral CD8 T cell responses of specific defects in the ability of the NK cells to control MCMV. This system allowed us to demonstrate, to our knowledge for the first time, that NK cells accelerate CD8 T cell responses against a viral infection in vivo. Moreover, we identify the underlying mechanism as the ability of NK cells to limit IFN-alpha/beta production to levels not immunosuppressive to the host. This is achieved through the early control of cytomegalovirus, which dramatically reduces the activation of plasmacytoid dendritic cells (pDCs for cytokine production, preserves the conventional dendritic cell (cDC compartment, and accelerates antiviral CD8 T cell responses. Conversely, exogenous IFN-alpha administration in resistant animals ablates cDCs and delays CD8 T cell activation in the face of NK cell control of viral replication. Collectively, our data demonstrate that the ability of NK cells to respond very early to cytomegalovirus infection critically contributes to balance the intensity of other innate immune responses, which dampens early immunopathology and promotes optimal initiation of antiviral CD8 T cell responses. Thus, the extent to which NK cell responses benefit the host goes beyond their direct antiviral effects and extends to the prevention of innate

Rectifier cabinet static breaker

International Nuclear Information System (INIS)

Costantino, R.A. Jr; Gliebe, R.J.

1992-01-01

A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload. 7 figs

Rectifier cabinet static breaker

Science.gov (United States)

Costantino, Jr, Roger A.; Gliebe, Ronald J.

1992-09-01

A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload.

CD83 Antibody Inhibits Human B Cell Responses to Antigen as well as Dendritic Cell-Mediated CD4 T Cell Responses.

Science.gov (United States)

Wong, Kuan Y; Baron, Rebecca; Seldon, Therese A; Jones, Martina L; Rice, Alison M; Munster, David J

2018-05-15

Anti-CD83 Ab capable of Ab-dependent cellular cytotoxicity can deplete activated CD83 + human dendritic cells, thereby inhibiting CD4 T cell-mediated acute graft-versus-host disease. As CD83 is also expressed on the surface of activated B lymphocytes, we hypothesized that anti-CD83 would also inhibit B cell responses to stimulation. We found that anti-CD83 inhibited total IgM and IgG production in vitro by allostimulated human PBMC. Also, Ag-specific Ab responses to immunization of SCID mice xenografted with human PBMC were inhibited by anti-CD83 treatment. This inhibition occurred without depletion of all human B cells because anti-CD83 lysed activated CD83 + B cells by Ab-dependent cellular cytotoxicity and spared resting (CD83 - ) B cells. In cultured human PBMC, anti-CD83 inhibited tetanus toxoid-stimulated B cell proliferation and concomitant dendritic cell-mediated CD4 T cell proliferation and expression of IFN-γ and IL-17A, with minimal losses of B cells (80% of B cells but had no effect on CD4 T cell proliferation and cytokine expression. By virtue of the ability of anti-CD83 to selectively deplete activated, but not resting, B cells and dendritic cells, with the latter reducing CD4 T cell responses, anti-CD83 may be clinically useful in autoimmunity and transplantation. Advantages might include inhibited expansion of autoantigen- or alloantigen-specific B cells and CD4 T cells, thus preventing further production of pathogenic Abs and inflammatory cytokines while preserving protective memory and regulatory cells. Copyright © 2018 by The American Association of Immunologists, Inc.

Geometrically nonlinear dynamic and static analysis of shallow spherical shell resting on two-parameters elastic foundations

International Nuclear Information System (INIS)

Civalek, Ö.

2014-01-01

In the present study nonlinear static and dynamic responses of shallow spherical shells resting on Winkler–Pasternak elastic foundations are carried out. The formulation of the shells is based on the Donnell theory. The nonlinear governing equations of motion of shallow shells are discretized in space and time domains using the discrete singular convolution and the differential quadrature methods, respectively. The validity of the present method is demonstrated by comparing the present results with those available in the open literature. The effects of the Winkler and Pasternak foundation parameters on nonlinear static and dynamic response of shells are investigated. Some results are also presented for circular plate as special case. Damping effect on nonlinear dynamic response of shells is studied. It is important to state that the increase in damping parameter causes decrease in the dynamic response of the shells. It is shown that the shear parameter of the foundation has a significant influence on the dynamic and static response of the shells. Also, the response of the shell is decreased with the increasing value of the shear parameter of the foundation. Parametric studies considering different geometric variables have also been investigated. -- Highlights: • Nonlinear responses of shallow spherical shells are presented. • The effects of foundation parameters are investigated. • Damping effect on nonlinear dynamic response of shells is also studied

A Tactile Sensor Using Piezoresistive Beams for Detection of the Coefficient of Static Friction.

Science.gov (United States)

Okatani, Taiyu; Takahashi, Hidetoshi; Noda, Kentaro; Takahata, Tomoyuki; Matsumoto, Kiyoshi; Shimoyama, Isao

2016-05-18

This paper reports on a tactile sensor using piezoresistive beams for detection of the coefficient of static friction merely by pressing the sensor against an object. The sensor chip is composed of three pairs of piezoresistive beams arranged in parallel and embedded in an elastomer; this sensor is able to measure the vertical and lateral strains of the elastomer. The coefficient of static friction is estimated from the ratio of the fractional resistance changes corresponding to the sensing elements of vertical and lateral strains when the sensor is in contact with an object surface. We applied a normal force on the sensor surface through objects with coefficients of static friction ranging from 0.2 to 1.1. The fractional resistance changes corresponding to vertical and lateral strains were proportional to the applied force. Furthermore, the relationship between these responses changed according to the coefficients of static friction. The experimental result indicated the proposed sensor could determine the coefficient of static friction before a global slip occurs.

Responses of Cells to Flow in Vitro

Directory of Open Access Journals (Sweden)

Shigehiro Hashimoto

2013-06-01

Full Text Available The response of cells to a flow has been studied in vitro. The response of cells was examined in two types of flow channels: a circumnutating flow in a donut-shaped open channel in a culture dish, and a one-way flow in a parallelepiped rhombus flow channel. Variation was made on the material of the parallelepiped channel to study on adhesion of cells to the plates: glass and polydimethylsiloxane. Behavior of cells on the plate was observed under a flow of a medium with an inverted phase-contrast-microscope. The shear stress on the plate is calculated with an estimated parabolic distribution of the velocity between the parallel plates. The adhesion of cells was evaluated with the cumulated shear, which is a product of the shear stress and the exposure time. The experimental results show that cells are responsive to the flow, which governs orientation, exfoliation, and differentiation. The response depends on the kinds of cells: endothelial cells orient along the stream line, although myocytes orient perpendicular to the stream line. The adhesion depends on the combination between scaffold and cell: myocytes are more adhesive to glass than cartilage cells, and fibroblasts are more adhesive to oxygenated polydimethylsiloxane than glass.

Moment measurements in dynamic and quasi-static spine segment testing using eccentric compression are susceptible to artifacts based on loading configuration.

Science.gov (United States)

Van Toen, Carolyn; Carter, Jarrod W; Oxland, Thomas R; Cripton, Peter A

2014-12-01

The tolerance of the spine to bending moments, used for evaluation of injury prevention devices, is often determined through eccentric axial compression experiments using segments of the cadaver spine. Preliminary experiments in our laboratory demonstrated that eccentric axial compression resulted in "unexpected" (artifact) moments. The aim of this study was to evaluate the static and dynamic effects of test configuration on bending moments during eccentric axial compression typical in cadaver spine segment testing. Specific objectives were to create dynamic equilibrium equations for the loads measured inferior to the specimen, experimentally verify these equations, and compare moment responses from various test configurations using synthetic (rubber) and human cadaver specimens. The equilibrium equations were verified by performing quasi-static (5 mm/s) and dynamic experiments (0.4 m/s) on a rubber specimen and comparing calculated shear forces and bending moments to those measured using a six-axis load cell. Moment responses were compared for hinge joint, linear slider and hinge joint, and roller joint configurations tested at quasi-static and dynamic rates. Calculated shear force and bending moment curves had similar shapes to those measured. Calculated values in the first local minima differed from those measured by 3% and 15%, respectively, in the dynamic test, and these occurred within 1.5 ms of those measured. In the rubber specimen experiments, for the hinge joint (translation constrained), quasi-static and dynamic posterior eccentric compression resulted in flexion (unexpected) moments. For the slider and hinge joints and the roller joints (translation unconstrained), extension ("expected") moments were measured quasi-statically and initial flexion (unexpected) moments were measured dynamically. In the cadaver experiments with roller joints, anterior and posterior eccentricities resulted in extension moments, which were unexpected and expected, for those

Static strain aging type AISI-304 austenitic stainless steel

International Nuclear Information System (INIS)

Trindade, M.B.

1981-03-01

Static strain aging of type AISI-304 austenitic stainless steel was studied from room temperature up to 623K by conducting tests in which the load was held approximately constant, continuously relaxing and unloaded. The aging times varied between 10s and 100h, using a plastic pre deformation of 9% in most of the cases. The static strain aging of 304 steel furnished an activation energy of 23,800 cal/mol. This implies that vacancies play an important role on the aging process. The curve of the variation of the discontinuous yielding with aging time presented different stages, to which specific mathematical expressions were developed. These facts permited the conclusion that Snoek type mechanisms are responsible for the aging in such conditions. (Author) [pt

Lowering data retention voltage in static random access memory array by post fabrication self-improvement of cell stability by multiple stress application

Science.gov (United States)

Mizutani, Tomoko; Takeuchi, Kiyoshi; Saraya, Takuya; Kobayashi, Masaharu; Hiramoto, Toshiro

2018-04-01

We propose a new version of the post fabrication static random access memory (SRAM) self-improvement technique, which utilizes multiple stress application. It is demonstrated that, using a device matrix array (DMA) test element group (TEG) with intrinsic channel fully depleted (FD) silicon-on-thin-buried-oxide (SOTB) six-transistor (6T) SRAM cells fabricated by the 65 nm technology, the lowering of data retention voltage (DRV) is more effectively achieved than using the previously proposed single stress technique.

Role of nesprin-1 in nuclear deformation in endothelial cells under static and uniaxial stretching conditions

Energy Technology Data Exchange (ETDEWEB)

Anno, Toshiro [Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai (Japan); Sakamoto, Naoya, E-mail: sakan@me.kawasaki-m.ac.jp [Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University, Sendai (Japan); Sato, Masaaki [Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai (Japan)

2012-07-20

Highlights: Black-Right-Pointing-Pointer Nesprin-1 knockdown decreases widths of nuclei in ECs under static condition. Black-Right-Pointing-Pointer Nuclear strain caused by stretching is increased by nesprin-1 knockdown in ECs. Black-Right-Pointing-Pointer We model mechanical interactions of F-actin with the nucleus in stretched cells. Black-Right-Pointing-Pointer F-actin bound to nesprin-1 may cause sustainable force transmission to the nucleus. -- Abstract: The linker of nucleus and cytoskeleton (LINC) complex, including nesprin-1, has been suggested to be crucial for many biological processes. Previous studies have shown that mutations in nesprin-1 cause abnormal cellular functions and diseases, possibly because of insufficient force transmission to the nucleus through actin filaments (F-actin) bound to nesprin-1. However, little is known regarding the mechanical interaction between the nucleus and F-actin through nesprin-1. In this study, we examined nuclear deformation behavior in nesprin-1 knocked-down endothelial cells (ECs) subjected to uniaxial stretching by evaluating nuclear strain from lateral cross-sectional images. The widths of nuclei in nesprin-1 knocked-down ECs were smaller than those in wild-type cells. In addition, nuclear strain in nesprin-1 knocked-down cells, which is considered to be compressed by the actin cortical layer, increased compared with that in wild-type cells under stretching condition. These results indicate that nesprin-1 knockdown releases the nucleus from the tension of F-actin bound to the nucleus, thereby increasing allowance for deformation before stretching, and that F-actin bound to the nucleus through nesprin-1 causes sustainable force transmission to the nucleus.

New Systematic CFD Methods to Calculate Static and Single Dynamic Stability Derivatives of Aircraft

Directory of Open Access Journals (Sweden)

Bai-gang Mi

2017-01-01

Full Text Available Several new systematic methods for high fidelity and reliability calculation of static and single dynamic derivatives are proposed in this paper. Angle of attack step response is used to obtain static derivative directly; then translation acceleration dynamic derivative and rotary dynamic derivative can be calculated by employing the step response motion of rate of the angle of attack and unsteady motion of pitching angular velocity step response, respectively. Longitudinal stability derivative calculations of SACCON UCAV are taken as test cases for validation. Numerical results of all cases achieve good agreement with reference values or experiments data from wind tunnel, which indicate that the proposed methods can be considered as new tools in the process of design and production of advanced aircrafts for their high efficiency and precision.

Neural Correlates of Facial Mimicry: Simultaneous Measurements of EMG and BOLD Responses during Perception of Dynamic Compared to Static Facial Expressions

Science.gov (United States)

Rymarczyk, Krystyna; Żurawski, Łukasz; Jankowiak-Siuda, Kamila; Szatkowska, Iwona

2018-01-01

Facial mimicry (FM) is an automatic response to imitate the facial expressions of others. However, neural correlates of the phenomenon are as yet not well established. We investigated this issue using simultaneously recorded EMG and BOLD signals during perception of dynamic and static emotional facial expressions of happiness and anger. During display presentations, BOLD signals and zygomaticus major (ZM), corrugator supercilii (CS) and orbicularis oculi (OO) EMG responses were recorded simultaneously from 46 healthy individuals. Subjects reacted spontaneously to happy facial expressions with increased EMG activity in ZM and OO muscles and decreased CS activity, which was interpreted as FM. Facial muscle responses correlated with BOLD activity in regions associated with motor simulation of facial expressions [i.e., inferior frontal gyrus, a classical Mirror Neuron System (MNS)]. Further, we also found correlations for regions associated with emotional processing (i.e., insula, part of the extended MNS). It is concluded that FM involves both motor and emotional brain structures, especially during perception of natural emotional expressions. PMID:29467691

Effects of static strain aging on residual stress stability and alternating bending strength of shot peened AISI 4140

Energy Technology Data Exchange (ETDEWEB)

Menig, R.; Schulze, V.; Voehringer, O. [Inst. fuer Werkstoffkunde 1, Univ. Karlsruhe (TH), Karlsruhe (Germany)

2002-07-01

Increases of residual stress stability and alternating bending strength of shot peened AISI 4140 are obtained by successive annealing treatments. This is caused by static strain aging effects, which lead to pinning of dislocations by carbon atoms and very small carbides. It will be shown that by well directed annealing of a quenched and tempered AISI 4140 it is possible to maximize the positive effects of static strain aging, without causing extended thermal residual stress relaxation. The amount of yield stress increases caused by static strain aging is quantified using tensile tests. Static strain aging is also found to be responsible for an increase of the quasi static and cyclic surface yield strength present after shot peening. (orig.)

Effect of shear stress on iPSC-derived human brain microvascular endothelial cells (dhBMECs).

Science.gov (United States)

DeStefano, Jackson G; Xu, Zinnia S; Williams, Ashley J; Yimam, Nahom; Searson, Peter C

2017-08-04

The endothelial cells that form the lumen of capillaries and microvessels are an important component of the blood-brain barrier. Cell phenotype is regulated by transducing a range of biomechanical and biochemical signals in the local microenvironment. Here we report on the role of shear stress in modulating the morphology, motility, proliferation, apoptosis, and protein and gene expression, of confluent monolayers of human brain microvascular endothelial cells derived from induced pluripotent stem cells. To assess the response of derived human brain microvascular endothelial cells (dhBMECs) to shear stress, confluent monolayers were formed in a microfluidic device. Monolayers were subjected to a shear stress of 4 or 12 dyne cm -2 for 40 h. Static conditions were used as the control. Live cell imaging was used to assess cell morphology, cell speed, persistence, and the rates of proliferation and apoptosis as a function of time. In addition, immunofluorescence imaging and protein and gene expression analysis of key markers of the blood-brain barrier were performed. Human brain microvascular endothelial cells exhibit a unique phenotype in response to shear stress compared to static conditions: (1) they do not elongate and align, (2) the rates of proliferation and apoptosis decrease significantly, (3) the mean displacement of individual cells within the monolayer over time is significantly decreased, (4) there is no cytoskeletal reorganization or formation of stress fibers within the cell, and (5) there is no change in expression levels of key blood-brain barrier markers. The characteristic response of dhBMECs to shear stress is significantly different from human and animal-derived endothelial cells from other tissues, suggesting that this unique phenotype that may be important in maintenance of the blood-brain barrier. The implications of this work are that: (1) in confluent monolayers of dhBMECs, tight junctions are formed under static conditions, (2) the formation

Theory of static friction: temperature and corrugation effects

International Nuclear Information System (INIS)

Franchini, A; Brigazzi, M; Santoro, G; Bortolani, V

2008-01-01

We present a study of the static friction, as a function of temperature, between two thick solid slabs. The upper one is formed of light particles and the substrate of heavy particles. We focus our attention on the interaction between the phonon fields of the two blocks and on the interface corrugation, among the various mechanisms responsible for the friction. To give evidence of the role played by the dynamical interaction of the substrate with the upper block, we consider both a substrate formed by fixed atoms and a substrate formed by mobile atoms. To study the effect of the corrugation, we model it by changing the range parameter σ in the Lennard-Jones interaction potential. We found that in the case of the mobile substrate there is a large momentum transfer from the substrate to the upper block. This momentum transfer increases on increasing the temperature and produces a large disorder in the upper block favouring a decrease of the static friction with respect to the case for a rigid substrate. Reducing the corrugation, we found that with a rigid substrate the upper block becomes nearly commensurate, producing an enhancement of the static friction with respect to that with a mobile substrate

Quasi-static and dynamic compressive deformation of a bulk nanolayered Ag–Cu eutectic alloy: Macroscopic response and dominant deformation mechanisms

International Nuclear Information System (INIS)

Kingstedt, O.T.; Eftink, B.; Lambros, J.; Robertson, I.M.

2014-01-01

Nanostructured multilayered material systems offer an attractive method of increasing material strength. This work examines the response of a bulk eutectic silver–copper material (Ag 60 Cu 40 , subscripts indicating atomic percent) which has a hierarchical structure of alternating Ag and Cu layers with thicknesses down to 50 nm. The hierarchical structure consists of two primary arrangements of layers, eutectic colonies of parallel layers, most commonly found at the material interior, and “grains” consisting of alternating Ag and Cu layers which emanate from a central region in a radial pattern, most commonly found at the material exterior surface. We show that the hierarchical structure causes a significant increase in the measured strength response when comparing the Ag 60 Cu 40 response to that of the constituent materials in their bulk nanograined or micrograined form. The deformation mechanisms of this material are studied under compressive loading over the quasi-static and dynamic regime (10 −3 –10 3 s −1 ) with strain between 5% and 50%

Adaptive Anchoring Model: How Static and Dynamic Presentations of Time Series Influence Judgments and Predictions.

Science.gov (United States)

Kusev, Petko; van Schaik, Paul; Tsaneva-Atanasova, Krasimira; Juliusson, Asgeir; Chater, Nick

2018-01-01

When attempting to predict future events, people commonly rely on historical data. One psychological characteristic of judgmental forecasting of time series, established by research, is that when people make forecasts from series, they tend to underestimate future values for upward trends and overestimate them for downward ones, so-called trend-damping (modeled by anchoring on, and insufficient adjustment from, the average of recent time series values). Events in a time series can be experienced sequentially (dynamic mode), or they can also be retrospectively viewed simultaneously (static mode), not experienced individually in real time. In one experiment, we studied the influence of presentation mode (dynamic and static) on two sorts of judgment: (a) predictions of the next event (forecast) and (b) estimation of the average value of all the events in the presented series (average estimation). Participants' responses in dynamic mode were anchored on more recent events than in static mode for all types of judgment but with different consequences; hence, dynamic presentation improved prediction accuracy, but not estimation. These results are not anticipated by existing theoretical accounts; we develop and present an agent-based model-the adaptive anchoring model (ADAM)-to account for the difference between processing sequences of dynamically and statically presented stimuli (visually presented data). ADAM captures how variation in presentation mode produces variation in responses (and the accuracy of these responses) in both forecasting and judgment tasks. ADAM's model predictions for the forecasting and judgment tasks fit better with the response data than a linear-regression time series model. Moreover, ADAM outperformed autoregressive-integrated-moving-average (ARIMA) and exponential-smoothing models, while neither of these models accounts for people's responses on the average estimation task. Copyright © 2017 The Authors. Cognitive Science published by Wiley

Single-word multiple-bit upsets in static random access devices

International Nuclear Information System (INIS)

Koga, R.; Pinkerton, S.D.; Lie, T.J.; Crawford, K.B.

1993-01-01

Energetic ions and protons can cause single event upsets (SEUs) in static random access memory (SRAM) cells. In some cases multiple bits may be upset as the result of a single event. Space-borne electronics systems incorporating high-density SRAM are vulnerable to single-word multiple-bit upsets (SMUs). The authors review here recent observations of SMU, present the results of a systematic investigation of the physical cell arrangements employed in several currently available SRAM device types, and discuss implications for the occurrence and mitigation of SMU

A Tactile Sensor Using Piezoresistive Beams for Detection of the Coefficient of Static Friction

Science.gov (United States)

Okatani, Taiyu; Takahashi, Hidetoshi; Noda, Kentaro; Takahata, Tomoyuki; Matsumoto, Kiyoshi; Shimoyama, Isao

2016-01-01

This paper reports on a tactile sensor using piezoresistive beams for detection of the coefficient of static friction merely by pressing the sensor against an object. The sensor chip is composed of three pairs of piezoresistive beams arranged in parallel and embedded in an elastomer; this sensor is able to measure the vertical and lateral strains of the elastomer. The coefficient of static friction is estimated from the ratio of the fractional resistance changes corresponding to the sensing elements of vertical and lateral strains when the sensor is in contact with an object surface. We applied a normal force on the sensor surface through objects with coefficients of static friction ranging from 0.2 to 1.1. The fractional resistance changes corresponding to vertical and lateral strains were proportional to the applied force. Furthermore, the relationship between these responses changed according to the coefficients of static friction. The experimental result indicated the proposed sensor could determine the coefficient of static friction before a global slip occurs. PMID:27213374

iNKT cells suppress the CD8+ T cell response to a murine Burkitt's-like B cell lymphoma.

Directory of Open Access Journals (Sweden)

Ryan L Bjordahl

Full Text Available The T cell response to B cell lymphomas differs from the majority of solid tumors in that the malignant cells themselves are derived from B lymphocytes, key players in immune response. B cell lymphomas are therefore well situated to manipulate their surrounding microenvironment to enhance tumor growth and minimize anti-tumor T cell responses. We analyzed the effect of T cells on the growth of a transplantable B cell lymphoma and found that iNKT cells suppressed the anti-tumor CD8(+ T cell response. Lymphoma cells transplanted into syngeneic wild type (WT mice or Jalpha18(-/- mice that specifically lack iNKT cells grew initially at the same rate, but only the mice lacking iNKT cells were able to reject the lymphoma. This effect was due to the enhanced activity of tumor-specific CD8(+ T cells in the absence of iNKT cells, and could be partially reversed by reconstitution of iNKT cells in Jalpha 18(-/- mice. Treatment of tumor-bearing WT mice with alpha -galactosyl ceramide, an activating ligand for iNKT cells, reduced the number of tumor-specific CD8(+ T cells. In contrast, lymphoma growth in CD1d1(-/- mice that lack both iNKT and type II NKT cells was similar to that in WT mice, suggesting that type II NKT cells are required for full activation of the anti-tumor immune response. This study reveals a tumor-promoting role for iNKT cells and suggests their capacity to inhibit the CD8(+ T cell response to B cell lymphoma by opposing the effects of type II NKT cells.

The static response function in Kohn-Sham theory: An appropriate basis for its matrix representation in case of finite AO basis sets

International Nuclear Information System (INIS)

Kollmar, Christian; Neese, Frank

2014-01-01

The role of the static Kohn-Sham (KS) response function describing the response of the electron density to a change of the local KS potential is discussed in both the theory of the optimized effective potential (OEP) and the so-called inverse Kohn-Sham problem involving the task to find the local KS potential for a given electron density. In a general discussion of the integral equation to be solved in both cases, it is argued that a unique solution of this equation can be found even in case of finite atomic orbital basis sets. It is shown how a matrix representation of the response function can be obtained if the exchange-correlation potential is expanded in terms of a Schmidt-orthogonalized basis comprising orbitals products of occupied and virtual orbitals. The viability of this approach in both OEP theory and the inverse KS problem is illustrated by numerical examples

A constitutive model for the compressive response of metallic closed-cell foams including micro-inertia effects

Directory of Open Access Journals (Sweden)

Barthélémy Romain

2015-01-01

Full Text Available Metallic foams have known a keen interest in the last decades. Their ability to undergo very large deformations while transmitting low stress levels make them capable of performing functions of protective layers against intense loadings and of energy absorbers, for instance. The behaviour of metal foams varies considerably between quasi-static and dynamic regimes. Those differences can be linked to the strain-rate sensitivity of the skeleton material and to micro-inertial effects (induced by the crushing of the foam cells. In the present work, a micromechanical model has been developed to take into account micro-inertia effects on the macroscopic behaviour of closed-cell foams under dynamic loading conditions. The proposed modelling is based on the dynamic homogenisation procedure introduced by Molinari and Mercier (J. Mech. Phys. Solids 49 (2001 1497–1516. Within this framework, the macrostress is the sum of two terms. The first one is a static stress, that can be described with any existing model of metal foam. The second contribution is a dynamic stress related to micro-inertia effects. Considering an initially spherical shell as a Representative Volume Element (RVE of the foam material, a closed-form expression of the dynamic stress was obtained. The proposed modelling was applied to shock propagation in aluminium foams (it should however be noted that the present theory is not restricted to uniaxial deformation but can be applied to arbitrary loadings. From experimental data of the literature, it is observed that incorporating micro-inertia effects allows one to achieve a better description of the foam shock response. This indicates that micro-inertia may have a significant influence on the dynamic behaviour of metallic foams.

Atmospheric stability analysis over statically and dynamically rough surfaces

Science.gov (United States)

Maric, Emina; Metzger, Meredith; Singha, Arindam; Sadr, Reza

2011-11-01

The ratio of buoyancy flux to turbulent kinetic energy production in the atmospheric surface layer is investigated experimentally for air flow over two types of surfaces characterized by static and dynamic roughness. In this study, ``static'' refers to the time-invariant nature of naturally-occurring roughness over a mud/salt playa; while, ``dynamic'' refers to the behavior of water waves along an air-water interface. In both cases, time-resolved measurements of the momentum and heat fluxes were acquired from synchronized 3D sonic anemometers mounted on a vertical tower. Field campaigns were conducted at two sites, representing the ``statically'' and ``dynamically'' rough surfaces, respectively: (1) the SLTEST facility in Utah's western desert, and (2) the new Doha airport in Qatar under construction along the coast of the Persian Gulf. Note, at site 2, anemometers were located directly above the water by extension from a tower secured to the end of a 1 km-long pier. Comparisons of the Monin-Obukhov length, flux Richardson number, and gradient Richardson number are presented, and discussed in the context of the observed evolution of the turbulent spectra in response to diurnal variations of atmospheric stability. Supported by the Qatar National Research Fund.

Energy conversion statics

CERN Document Server

Messerle, H K; Declaris, Nicholas

2013-01-01

Energy Conversion Statics deals with equilibrium situations and processes linking equilibrium states. A development of the basic theory of energy conversion statics and its applications is presented. In the applications the emphasis is on processes involving electrical energy. The text commences by introducing the general concept of energy with a survey of primary and secondary energy forms, their availability, and use. The second chapter presents the basic laws of energy conversion. Four postulates defining the overall range of applicability of the general theory are set out, demonstrating th

Oscillatory corticospinal activity during static contraction of ankle muscles is reduced in healthy old versus young adults

DEFF Research Database (Denmark)

Spedden, Meaghan Elizabeth; Nielsen, Jens Bo; Geertsen, Svend Sparre

2018-01-01

Aging is accompanied by impaired motor function, but age-related changes in neural networks responsible for generating movement are not well understood. We aimed to investigate the functional oscillatory coupling between activity in the sensorimotor cortex and ankle muscles during static contract......Aging is accompanied by impaired motor function, but age-related changes in neural networks responsible for generating movement are not well understood. We aimed to investigate the functional oscillatory coupling between activity in the sensorimotor cortex and ankle muscles during static...... contraction. Fifteen young (20–26 yr) and fifteen older (65–73 yr) subjects were instructed to match a target force by performing static ankle dorsi- or plantar flexion, while electroencephalographic (EEG) activity was recorded from the cortex and electromyographic (EMG) activity was recorded from dorsi...

A Pedagogical Model of Static Friction

OpenAIRE

Pickett, Galen T.

2015-01-01

While dry Coulombic friction is an elementary topic in any standard introductory course in mechanics, the critical distinction between the kinetic and static friction forces is something that is both hard to teach and to learn. In this paper, I describe a geometric model of static friction that may help introductory students to both understand and apply the Coulomb static friction approximation.

Impact of the duct static pressure reset control strategy on the energy consumption by the HVAC system

Directory of Open Access Journals (Sweden)

Walaszczyk Juliusz

2017-01-01

Full Text Available This article addresses different duct static pressure control strategies which could be implemented in variable air volume air-conditioning systems (VAV. Two pressure reset control strategies are compared to the commonly used control solution based on the “Constant static pressure” method. First pressure reset control strategy, known as PID Control, uses signals from VAV boxes controllers to reset duct static pressure in a way that one of the VAV dampers is maintained almost entirely open. Second strategy decreases static pressure setpoint until an adjustable number of pressure requests occur. As a response to the certain amount of requests, static pressure setpoint is increased. This strategy is called Trim & Respond. Both static pressure reset control strategies described in this paper are considered to have more significant potential for energy savings than the “Constant static pressure” method. In order to validate this potential, several simulations for different control strategies were carried out and the obtained results are compared and analysed. The theoretical limit of the energy savings - set of the optimal control actions, was estimated with Nelder-Mead algorithm and also presented in this article. General description of the static pressure control strategies "Constant static pressure", PID Control and Trim & Respond is given.

Statics of Historic Masonry Constructions

CERN Document Server

Como, Mario

2013-01-01

Masonry constructions are the great majority of the buildings in Europe’s historic centres and the most important monuments in its architectural heritage. Given the age of much of these constructions, the demand for safety assessments and restoration projects is pressing and constant. This book aims to help fill this demand presenting a comprehensive new statics of masonry constructions. The book, result of thirty years of research and professional experience, gives the fundamentals of statics of the masonry solid, then applied to the study of statics of arches, piers and vaults. Further, combining engineering and architecture and through an interdisciplinary approach, the book investigates the statical behaviour of many historic monuments, as the Pantheon, the Colosseum,  the domes of S. Maria del Fiore in Florence and of St. Peter in Rome, the Tower of Pisa, the Gothic Cathedrals and the Masonry Buildings under seismic actions.

Normalization of cell responses in cat striate cortex

Science.gov (United States)

Heeger, D. J.

1992-01-01

Simple cells in the striate cortex have been depicted as half-wave-rectified linear operators. Complex cells have been depicted as energy mechanisms, constructed from the squared sum of the outputs of quadrature pairs of linear operators. However, the linear/energy model falls short of a complete explanation of striate cell responses. In this paper, a modified version of the linear/energy model is presented in which striate cells mutually inhibit one another, effectively normalizing their responses with respect to stimulus contrast. This paper reviews experimental measurements of striate cell responses, and shows that the new model explains a significantly larger body of physiological data.

Automatic incrementalization of Prolog based static analyses

DEFF Research Database (Denmark)

Eichberg, Michael; Kahl, Matthias; Saha, Diptikalyan

2007-01-01

Modem development environments integrate various static analyses into the build process. Analyses that analyze the whole project whenever the project changes are impractical in this context. We present an approach to automatic incrementalization of analyses that are specified as tabled logic...... programs and evaluated using incremental tabled evaluation, a technique for efficiently updating memo tables in response to changes in facts and rules. The approach has been implemented and integrated into the Eclipse IDE. Our measurements show that this technique is effective for automatically...

Storm track response to climate change: Insights from simulations using an idealized dry GCM.

Science.gov (United States)

Mbengue, Cheikh; Schneider, Tapio

2013-04-01

poleward migration of the storm tracks. We demonstrate a poleward migration of the midlatitude storm tracks in dry atmospheres with fixed pole-equator temperature contrast and increasing radiative equilibrium mean temperature, without changes in convective static stability. We also show scalings between the location of maxima of surface MAPE and of barotropic EKE. In the simulations where we independently vary tropical convective static stability, we find a marked poleward migration of the storm tracks. However, our decomposition shows that meridional temperature gradients, and not static stability, determine the location and the intensity of the storm tracks. This suggests that although the storm tracks are sensitive to tropical convective static stability, it influences them indirectly. Furthermore, our simulations show that the storm tracks generally migrate in tandem with the terminus of the Hadley cell. Therefore, we hypothesize that it is possible that the Hadley cell provides the tropical-extratropical communication necessary to generate the storm track response to tropical convective static stability we observe in the simulations. The results contained herein could be used to supplement ongoing storm track research in moist atmospheres using comparatively more comprehensive GCMs to understand storm track dynamics in earth-like environments.

Static Transition Compression

DEFF Research Database (Denmark)

Danvy, Olivier; Damian, Daniel

2001-01-01

Starting from an operational specification of a translation from a structured to an unstructured imperative language, we point out how a compositional and context-insensitive translation gives rise to static chains of jumps. Taking an inspiration from the notion of continuation, we state a new...... compositional and context-sensitive specification that provably gives rise to no static chains of jumps, no redundant labels, and no unused labels. It is defined with one inference rule per syntactic construct and operates in linear time and space on the size of the source program (indeed it operates in one...

Statics and Mechanics of Structures

DEFF Research Database (Denmark)

Krenk, Steen; Høgsberg, Jan Becker

The statics and mechanics of structures form a core aspect of civil engineering. This book provides an introduction to the subject, starting from classic hand-calculation types of analysis and gradually advancing to a systematic form suitable for computer implementation. It starts with statically...

Investigation of the response of low-dose irradiated cells. Pt. 2. Radio-adaptive response of human embryonic cells is related to cell-to-cell communication

International Nuclear Information System (INIS)

Ishii, Keiichiro; Watanabe, Masami.

1994-01-01

To clarify the radio-adaptive response of normal cells to low-dose radiation, we irradiated human embryonic cells and HeLa cells with low-dose X-ray and examined the changes in sensitivity to subsequent high-dose X-irradiation. The results obtained were as follows; (1) When HE cells were irradiated by a high-dose of 200 cGy, the growth ratio of the living cells five days after the irradiation decreased to 37% of that of the cells which received no X-irradiation. When the cells received a preliminary irradiation of 10 to 20 cGy four hours before the irradiation of 200 cGy, the relative growth ratios increased significantly to 45-53%. (2) This preliminary irradiation effect was not observed in HeLa cells, being cancer cells. (3) When the HE cells suspended in a Ca 2+ iron-free medium or TPA added medium while receiving the preliminary irradiation of 13 cGy, the effect of the preliminary irradiation in increasing the relative growth ratio of living cells was not observed. (4) This indicates that normal cells shows an adaptive response to low-dose radiation and become more radioresistant. This phenomenon is considered to involve cell-to-cell communication maintained in normal cells and intracellular signal transduction in which Ca 2+ ion plays a role. (author)

An improved technique for quasi-static C-V measurements

International Nuclear Information System (INIS)

Turan, R.; Finstad, T.G.

1990-10-01

A new automated quasi-static C-V measurement technique for MOS capacitors has been developed. This techniques uses an integrating electrometer to measure the charge accumulated on a MOS capacitor in response of a small voltage step. Making use of the internal data storage system of a commercial electrometer and a personal computer, the charge Q on the MOS capacitor is measured as a function of time t and stored. The capacitance is then obtained by analyzing this Q-t data set. A Si MOS sample is measured and analyzed in terms of interface charges as an example. Advantages over a commercial quasi-static meter which uses similar measurement technique are presented. It is also shown that this technique is potentially capable of measuring both high and low frequency C-V curves simultaneously. 9 refs. 5 figs

STATIC{sub T}EMP: a useful computer code for calculating static formation temperatures in geothermal wells

Energy Technology Data Exchange (ETDEWEB)

Santoyo, E. [Universidad Nacional Autonoma de Mexico, Centro de Investigacion en Energia, Temixco (Mexico); Garcia, A.; Santoyo, S. [Unidad Geotermia, Inst. de Investigaciones Electricas, Temixco (Mexico); Espinosa, G. [Universidad Autonoma Metropolitana, Co. Vicentina (Mexico); Hernandez, I. [ITESM, Centro de Sistemas de Manufactura, Monterrey (Mexico)

2000-07-01

The development and application of the computer code STATIC{sub T}EMP, a useful tool for calculating static formation temperatures from actual bottomhole temperature data logged in geothermal wells is described. STATIC{sub T}EMP is based on five analytical methods which are the most frequently used in the geothermal industry. Conductive and convective heat flow models (radial, spherical/radial and cylindrical/radial) were selected. The computer code is a useful tool that can be reliably used in situ to determine static formation temperatures before or during the completion stages of geothermal wells (drilling and cementing). Shut-in time and bottomhole temperature measurements logged during well completion activities are required as input data. Output results can include up to seven computations of the static formation temperature by each wellbore temperature data set analysed. STATIC{sub T}EMP was written in Fortran-77 Microsoft language for MS-DOS environment using structured programming techniques. It runs on most IBM compatible personal computers. The source code and its computational architecture as well as the input and output files are described in detail. Validation and application examples on the use of this computer code with wellbore temperature data (obtained from specialised literature) and with actual bottomhole temperature data (taken from completion operations of some geothermal wells) are also presented. (Author)

SAP-4, Static and Dynamic Linear System Stress Analysis for Various Structures

International Nuclear Information System (INIS)

Zawadzki, S.

1984-01-01

1 - Description of problem or function: SAP4 is a structural analysis program for determining the static and dynamic response of linear systems. The structural systems to be analyzed may be composed of combinations of a number of different structural elements. Currently the program contains the following element types - (a) three-dimensional truss element, (b) three-dimensional beam element, (c) plane stress and plane strain element, (d) two-dimensional axisymmetric solid, (e) three-dimensional solid, (f) variable-number nodes thick shell and three-dimensional element, (g) thin-plate or thin-shell element, (h) boundary element, and (i) pipe element (tangent and bend). 2 - Method of solution: The formation of the structure matrices is carried out in the same way in a static or dynamic analysis. The static analysis is continued by solving the equations of equilibrium followed by the computation of element stresses. In a dynamic analysis the choice is between frequency calculations only, frequency calculations followed by response history analysis, frequency calculations followed by response spectrum analysis, or response history analysis by direct integration. To obtain the frequencies and vibration mode shapes, solution routines are used which calculate the required eigenvalues and eigenvectors directly without a transformation of the structure stiffness matrix and mass matrix to a reduced form. To perform the direct integration an unconditionally stable scheme is used, which also operates on the original structure stiffness matrix and mass matrix. In this manner the program operation and input data required for a dynamic analysis are simple extensions of those needed for a static analysis. 3 - Restrictions on the complexity of the problem: The capacity of the program depends mainly on the total number of nodal points in the system, the number of eigenvalues needed in the dynamic analysis, and the computer used. There is practically no restriction on the number of

Epidermal stem cells response to radiative genotoxic stress

International Nuclear Information System (INIS)

Marie, Melanie

2013-01-01

Human skin is the first organ exposed to various environmental stresses, which requires the development by skin stem cells of specific mechanisms to protect themselves and to ensure tissue homeostasis. As stem cells are responsible for the maintenance of epidermis during individual lifetime, the preservation of genomic integrity in these cells is essential. My PhD aimed at exploring the mechanisms set up by epidermal stem cells in order to protect themselves from two genotoxic stresses, ionizing radiation (Gamma Rays) and ultraviolet radiation (UVB). To begin my PhD, I have taken part of the demonstration of protective mechanisms used by keratinocyte stem cells after ionizing radiation. It has been shown that these cells are able to rapidly repair most types of radiation-induced DNA damage. Furthermore, we demonstrated that this repair is activated by the fibroblast growth factor 2 (FGF2). In order to know if this protective mechanism is also operating in cutaneous carcinoma stem cells, we investigated the response to gamma Rays of carcinoma stem cells isolated from a human carcinoma cell line. As in normal keratinocyte stem cells, we demonstrated that cancer stem cells could rapidly repair radio-induced DNA damage. Furthermore, fibroblast growth factor 2 also mediates this repair, notably thanks to its nuclear isoforms. The second project of my PhD was to study human epidermal stem cells and progenitors responses to UVB radiation. Once cytometry and irradiation conditions were set up, the toxicity of UVB radiation has been evaluate in the primary cell model. We then characterized UVB photons effects on cell viability, proliferation and repair of DNA damage. This study allowed us to bring out that responses of stem cells and their progeny to UVB are different, notably at the level of part of their repair activity of DNA damage. Moreover, progenitors and stem cells transcriptomic responses after UVB irradiation have been study in order to analyze the global

Statics and mechanics of structures

CERN Document Server

Krenk, Steen

2013-01-01

The statics and mechanics of structures form a core aspect of civil engineering. This book provides an introduction to the subject, starting from classic hand-calculation types of analysis and gradually advancing to a systematic form suitable for computer implementation. It starts with statically determinate structures in the form of trusses, beams and frames. Instability is discussed in the form of the column problem - both the ideal column and the imperfect column used in actual column design. The theory of statically indeterminate structures is then introduced, and the force and deformation methods are explained and illustrated. An important aspect of the book’s approach is the systematic development of the theory in a form suitable for computer implementation using finite elements. This development is supported by two small computer programs, MiniTruss and MiniFrame, which permit static analysis of trusses and frames, as well as linearized stability analysis. The book’s final section presents related ...

Semiallogenic fusions of MSI+ tumor cells and activated B cells induce MSI-specific T cell responses

International Nuclear Information System (INIS)

Garbe, Yvette; Klier, Ulrike; Linnebacher, Michael

2011-01-01

Various strategies have been developed to transfer tumor-specific antigens into antigen presenting cells in order to induce cytotoxic T cell responses against tumor cells. One approach uses cellular vaccines based on fusions of autologous antigen presenting cells and allogeneic tumor cells. The fusion cells combine antigenicity of the tumor cell with optimal immunostimulatory capacity of the antigen presenting cells. Microsatellite instability caused by mutational inactivation of DNA mismatch repair genes results in translational frameshifts when affecting coding regions. It has been shown by us and others that these mutant proteins lead to the presentation of immunogenic frameshift peptides that are - in principle - recognized by a multiplicity of effector T cells. We chose microsatellite instability-induced frameshift antigens as ideal to test for induction of tumor specific T cell responses by semiallogenic fusions of microsatellite instable carcinoma cells with CD40-activated B cells. Two fusion clones of HCT116 with activated B cells were selected for stimulation of T cells autologous to the B cell fusion partner. Outgrowing T cells were phenotyped and tested in functional assays. The fusion clones expressed frameshift antigens as well as high amounts of MHC and costimulatory molecules. Autologous T cells stimulated with these fusions were predominantly CD4 + , activated, and reacted specifically against the fusion clones and also against the tumor cell fusion partner. Interestingly, a response toward 6 frameshift-derived peptides (of 14 tested) could be observed. Cellular fusions of MSI + carcinoma cells and activated B cells combine the antigen-presenting capacity of the B cell with the antigenic repertoire of the carcinoma cell. They present frameshift-derived peptides and can induce specific and fully functional T cells recognizing not only fusion cells but also the carcinoma cells. These hybrid cells may have great potential for cellular immunotherapy and

Phenomenon of adaptive response of cells in radiobiology

International Nuclear Information System (INIS)

Fillipovich, I.V.

1991-01-01

Consideration is given to various adaptive reactions to low-level radiation, their association with an absorbed dose, dose rate, radiation quality and time-interval between exposures, as well as with a cell cycle phase. Possible mechanisms of the adaptive response and the character and role of DNA damages, that can induce gene expression of the adaptive response, are discussed. The data on the influence of a preliminary long-term exposure to low-level radiation on the radiosensitivity of biological objects are analyzed with due regard for the adaptive cell response. It is concluded that the adaptive response of cells to ionizing radiation is a particular case of the phenomenon of cell adaptation of the effect of genotoxic factors of the environment

Static Members of Classes in C#

Directory of Open Access Journals (Sweden)

Adrian LUPASC

2017-12-01

Full Text Available The C# language is object-oriented, which is why the declared member data must be part of a class. Thus, there is no possibility to declare certain variables that can be accessed from anywhere within the application, as it happens, for example, with global variables at the C language level. Making this work in C# is possible through static members of the class. Declaring a class implies defining some of its member data that later receive values when creating each object. A static member of the class can be interpreted as belonging only to the class, not to the objects subsequently created, which means that for the non-static data, there are as many children as there were objects created, while for the static ones there is only one copy, regardless of the number of created objects. In this regard, this paper presents the main aspects that characterize these abstract concepts of object oriented programming in general and C# language in particular, detailing how to develop an application that includes both static and non-static members. At the same time, particularities in the mirror for the two types of data, restrictions on use and potential limitations are presented.

Static field influences on transcranial magnetic stimulation: considerations for TMS in the scanner environment.

Science.gov (United States)

Yau, Jeffrey M; Jalinous, Reza; Cantarero, Gabriela L; Desmond, John E

2014-01-01

Transcranial magnetic stimulation (TMS) can be combined with functional magnetic resonance imaging (fMRI) to simultaneously manipulate and monitor human cortical responses. Although tremendous efforts have been directed at characterizing the impact of TMS on image acquisition, the influence of the scanner's static field on the TMS coil has received limited attention. The aim of this study was to characterize the influence of the scanner's static field on TMS. We hypothesized that spatial variations in the static field could account for TMS field variations in the scanner environment. Using an MRI-compatible TMS coil, we estimated TMS field strengths based on TMS-induced voltage changes measured in a search coil. We compared peak field strengths obtained with the TMS coil positioned at different locations (B0 field vs fringe field) and orientations in the static field. We also measured the scanner's static field to derive a field map to account for TMS field variations. TMS field strength scaled depending on coil location and orientation with respect to the static field. Larger TMS field variations were observed in fringe field regions near the gantry as compared to regions inside the bore or further removed from the bore. The scanner's static field also exhibited the greatest spatial variations in fringe field regions near the gantry. The scanner's static field influences TMS fields and spatial variations in the static field correlate with TMS field variations. Coil orientation changes in the B0 field did not result in substantial TMS field variations. TMS field variations can be minimized by delivering TMS in the bore or outside of the 0-70 cm region from the bore entrance. Copyright © 2014 Elsevier Inc. All rights reserved.

Multi objective optimization of foam-filled circular tubes for quasi-static and dynamic responses

Directory of Open Access Journals (Sweden)

Fauzan Djamaluddin

Full Text Available AbstractFuel consumption and safety are currently key aspects in automobile design. The foam-filled thin-walled aluminium tube represents a potentially effective material for use in the automotive industry, due to its energy absorption capability and light weight. Multi-objective crashworthiness design optimization for foam-filled double cylindrical tubes is presented in this paper. The double structures are impacted by a rigid wall simulating quasi-static and dynamic loadings. The optimal parameters under consideration are the minimum peak crushing force and maximum specific energy absorption, using the non-dominated sorting genetic algorithm-II (NSGA-II technique. Radial basis functions (RBF and D-Optimal are adopted to determine the more complex crashworthiness functional objectives. The comparison is performed by finite element analysis of the impact crashworthiness characteristics in tubes under static and dynamic loads. Finally, the optimum crashworthiness performance of empty and foam-filled double tubes is investigated and compared to the traditional single foam-filled tube. The results indicate that the foam-filled double aluminium circular tube can be recommended for crashworthy structures.

T-cell responses in malaria

DEFF Research Database (Denmark)

Hviid, L; Jakobsen, P H; Abu-Zeid, Y A

1992-01-01

Malaria is caused by infection with protozoan parasites of the genus Plasmodium. It remains one of the most severe health problems in tropical regions of the world, and the rapid spread of resistance to drugs and insecticides has stimulated intensive research aimed at the development of a malaria...... vaccine. Despite this, no efficient operative vaccine is currently available. A large amount of information on T-cell responses to malaria antigens has been accumulated, concerning antigens derived from all stages of the parasite life cycle. The present review summarizes some of that information......, and discusses factors affecting the responses of T cells to malaria antigens....

The improved quasi-static method vs the direct method: a case study for CANDU reactor transients

International Nuclear Information System (INIS)

Kaveh, S.; Koclas, J.; Roy, R.

1999-01-01

Among the large number of methods for the transient analysis of nuclear reactors, the improved quasi-static procedure is one of the most widely used. In recent years, substantial increase in both computer speed and memory has motivated a rethinking of the limitations of this method. The overall goal of the present work is a systematic comparison between the improved quasi-static and the direct method (mesh-centered finite difference) for realistic CANDU transient simulations. The emphasis is on the accuracy of the solutions as opposed to the computational speed. Using the computer code NDF, a typical realistic transient of CANDU reactor has been analyzed. In this transient the response of the reactor regulating system to a substantial local perturbation (sudden extraction of the five adjuster rods) has been simulated. It is shown that when updating the detector responses is of major importance, it is better to use a well-optimized direct method rather than the improved quasi-static method. (author)

Flexible Piezoelectric-Induced Pressure Sensors for Static Measurements Based on Nanowires/Graphene Heterostructures.

Science.gov (United States)

Chen, Zefeng; Wang, Zhao; Li, Xinming; Lin, Yuxuan; Luo, Ningqi; Long, Mingzhu; Zhao, Ni; Xu, Jian-Bin

2017-05-23

The piezoelectric effect is widely applied in pressure sensors for the detection of dynamic signals. However, these piezoelectric-induced pressure sensors have challenges in measuring static signals that are based on the transient flow of electrons in an external load as driven by the piezopotential arisen from dynamic stress. Here, we present a pressure sensor with nanowires/graphene heterostructures for static measurements based on the synergistic mechanisms between strain-induced polarization charges in piezoelectric nanowires and the caused change of carrier scattering in graphene. Compared to the conventional piezoelectric nanowire or graphene pressure sensors, this sensor is capable of measuring static pressures with a sensitivity of up to 9.4 × 10 -3 kPa -1 and a fast response time down to 5-7 ms. This demonstration of pressure sensors shows great potential in the applications of electronic skin and wearable devices.

Static Tensile and Transient Dynamic Response of Cracked Aluminum Plate Repaired with Composite Patch - Numerical Study

Science.gov (United States)

Khalili, S. M. R.; Shariyat, M.; Mokhtari, M.

2014-06-01

In this study, the central cracked aluminum plates repaired with two sided composite patches are investigated numerically for their response to static tensile and transient dynamic loadings. Contour integral method is used to define and evaluate the stress intensity factors at the crack tips. The reinforcement for the composite patches is carbon fibers. The effect of adhesive thickness and patch thickness and configuration in tensile loading case and pre-tension, pre-compression and crack length effect on the evolution of the mode I stress intensity factor (SIF) (KI) of the repaired structure under transient dynamic loading case are examined. The results indicated that KI of the central cracked plate is reduced by 1/10 to 1/2 as a result of the bonded composite patch repair in tensile loading case. The crack length and the pre-loads are more effective in repaired structure in transient dynamic loading case in which, the 100 N pre-compression reduces the maximum KI for about 40 %, and the 100 N pre-tension reduces the maximum KI after loading period, by about 196 %.

System-wide Analysis of the T Cell Response

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Ruxandra Covacu

2016-03-01

Full Text Available The T cell receptor (TCR controls the cellular adaptive immune response to antigens, but our understanding of TCR repertoire diversity and response to challenge is still incomplete. For example, TCR clones shared by different individuals with minimal alteration to germline gene sequences (public clones are detectable in all vertebrates, but their significance is unknown. Although small in size, the zebrafish TCR repertoire is controlled by processes similar to those operating in mammals. Thus, we studied the zebrafish TCR repertoire and its response to stimulation with self and foreign antigens. We found that cross-reactive public TCRs dominate the T cell response, endowing a limited TCR repertoire with the ability to cope with diverse antigenic challenges. These features of vertebrate public TCRs might provide a mechanism for the rapid generation of protective T cell immunity, allowing a short temporal window for the development of more specific private T cell responses.

A PSP-based small-signal MOSFET model for both quasi-static and nonquasi-static operations

NARCIS (Netherlands)

Aarts, A.C.T.; Smit, G.D.J.; Scholten, A.J.; Klaassen, D.B.M.

2008-01-01

In this paper, a small-signal MOSFET model is described, which takes the local effects of both velocity saturation and transverse mobility reduction into account. The model is based on the PSP model and is valid for both quasi-static and nonquasi-static (NQS) operations. Recently, it has been found

Martian Atmospheric Pressure Static Charge Elimination Tool

Science.gov (United States)

Johansen, Michael R.

2014-01-01

A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

Gas Measurement Using Static Fourier Transform Infrared Spectrometers.

Science.gov (United States)

Köhler, Michael H; Schardt, Michael; Rauscher, Markus S; Koch, Alexander W

2017-11-13

Online monitoring of gases in industrial processes is an ambitious task due to adverse conditions such as mechanical vibrations and temperature fluctuations. Whereas conventional Fourier transform infrared (FTIR) spectrometers use rather complex optical and mechanical designs to ensure stable operation, static FTIR spectrometers do not require moving parts and thus offer inherent stability at comparatively low costs. Therefore, we present a novel, compact gas measurement system using a static single-mirror Fourier transform spectrometer (sSMFTS). The system works in the mid-infrared range from 650 cm - 1 to 1250 cm - 1 and can be operated with a customized White cell, yielding optical path lengths of up to 120 cm for highly sensitive quantification of gas concentrations. To validate the system, we measure different concentrations of 1,1,1,2-Tetrafluoroethane (R134a) and perform a PLS regression analysis of the acquired infrared spectra. Thereby, the measured absorption spectra show good agreement with reference data. Since the system additionally permits measurement rates of up to 200 Hz and high signal-to-noise ratios, an application in process analysis appears promising.

Static and dynamic properties of two-dimensional Coulomb clusters.

Science.gov (United States)

Ash, Biswarup; Chakrabarti, J; Ghosal, Amit

2017-10-01

We study the temperature dependence of static and dynamic responses of Coulomb interacting particles in two-dimensional confinements across the crossover from solid- to liquid-like behaviors. While static correlations that investigate the translational and bond orientational order in the confinements show the footprints of hexatic-like phase at low temperatures, dynamics of the particles slow down considerably in this phase, reminiscent of a supercooled liquid. Using density correlations, we probe long-lived heterogeneities arising from the interplay of the irregularity in the confinement and long-range Coulomb interactions. The relaxation at multiple time scales show stretched-exponential decay of spatial correlations in irregular traps. Temperature dependence of characteristic time scales, depicting the structural relaxation of the system, show striking similarities with those observed for the glassy systems, indicating that some of the key signatures of supercooled liquids emerge in confinements with lower spatial symmetries.

Static electric fields modify the locomotory behaviour of cockroaches.

Science.gov (United States)

Jackson, Christopher W; Hunt, Edmund; Sharkh, Suleiman; Newland, Philip L

2011-06-15

Static electric fields are found throughout the environment and there is growing interest in how electric fields influence insect behaviour. Here we have analysed the locomotory behaviour of cockroaches (Periplaneta americana) in response to static electric fields at levels equal to and above those found in the natural environment. Walking behaviour (including velocity, distance moved, turn angle and time spent walking) were analysed as cockroaches approached an electric field boundary in an open arena, and also when continuously exposed to an electric field. On approaching an electric field boundary, the greater the electric field strength the more likely a cockroach would be to turn away from, or be repulsed by, the electric field. Cockroaches completely exposed to electric fields showed significant changes in locomotion by covering less distance, walking slowly and turning more often. This study highlights the importance of electric fields on the normal locomotory behaviour of insects.

Dynamic culture induces a cell type-dependent response impacting on the thickness of engineered connective tissues.

Science.gov (United States)

Fortier, Guillaume Marceau; Gauvin, Robert; Proulx, Maryse; Vallée, Maud; Fradette, Julie

2013-04-01

Mesenchymal cells are central to connective tissue homeostasis and are widely used for tissue-engineering applications. Dermal fibroblasts and adipose-derived stromal cells (ASCs) allow successful tissue reconstruction by the self-assembly approach of tissue engineering. This method leads to the production of multilayered tissues, devoid of exogenous biomaterials, that can be used as stromal compartments for skin or vesical reconstruction. These tissues are formed by combining cell sheets, generated through cell stimulation with ascorbic acid, which favours the cell-derived production/organization of matrix components. Since media motion can impact on cell behaviour, we investigated the effect of dynamic culture on mesenchymal cells during tissue reconstruction, using the self-assembly method. Tissues produced using ASCs in the presence of a wave-like movement were nearly twice thicker than under standard conditions, while no difference was observed for tissues produced from dermal fibroblasts. The increased matrix deposition was not correlated with an increased proliferation of ASCs, or by higher transcript levels of fibronectin or collagens I and III. A 30% increase of type V collagen mRNA was observed. Interestingly, tissues engineered from dermal fibroblasts featured a four-fold higher level of MMP-1 transcripts under dynamic conditions. Mechanical properties were similar for tissues reconstructed using dynamic or static conditions. Finally, cell sheets produced using ASCs under dynamic conditions could readily be manipulated, resulting in a 2 week reduction of the production time (from 5 to 3 weeks). Our results describe a distinctive property of ASCs' response to media motion, indicating that their culture under dynamic conditions leads to optimized tissue engineering. Copyright © 2011 John Wiley & Sons, Ltd.

Static and dynamic properties of frictional phenomena in a one-dimensional system with randomness

International Nuclear Information System (INIS)

Kawaguchi, T.; Matsukawa, H.

1997-01-01

Static and dynamic frictional phenomena at the interface with random impurities are investigated in a two-chain model with incommensurate structure. Static frictional force is caused by the impurity pinning and/or by the pinning due to the regular potential, which is responsible for the breaking of analyticity transition for impurity-free cases. It is confirmed that the static frictional force is always finite in the presence of impurities, in contrast to the impurity-free system. The nature of impurity pinning is discussed in connection with that in density waves. The kinetic frictional force of a steady sliding state is also investigated numerically. The relationship between the sliding velocity dependence of the kinetic frictional force and the strength of impurity potential is discussed. copyright 1997 The American Physical Society

On the relationship between ontogenetic and static allometry.

Science.gov (United States)

Pélabon, Christophe; Bolstad, Geir H; Egset, Camilla K; Cheverud, James M; Pavlicev, Mihaela; Rosenqvist, Gunilla

2013-02-01

Ontogenetic and static allometries describe how a character changes in size when the size of the organism changes during ontogeny and among individuals measured at the same developmental stage, respectively. Understanding the relationship between these two types of allometry is crucial to understanding the evolution of allometry and, more generally, the evolution of shape. However, the effects of ontogenetic allometry on static allometry remain largely unexplored. Here, we first show analytically how individual variation in ontogenetic allometry and body size affect static allometry. Using two longitudinal data sets on ontogenetic and static allometry, we then estimate variances and covariances for the different parameters of the ontogenetic allometry defined in our model and assess their relative contribution to the static allometric slope. The mean ontogenetic allometry is the main parameter that determines the static allometric slope, while the covariance between the ontogenetic allometric slope and body size generates most of the discrepancies between ontogenetic and static allometry. These results suggest that the apparent evolutionary stasis of the static allometric slope is not generated by internal (developmental) constraints but more likely results from external constraints imposed by selection.

Regulation of T cell responses in atherosclerosis

NARCIS (Netherlands)

Puijvelde, Gijsbrecht Henricus Maria van

2007-01-01

One of the most important characteristics of atherosclerosis is the chronic inflammatory response in which T cells and NKT cells are very important. In this thesis several methods to modulate the activity of these T and NKT cells in atherosclerosis are described. The induction of regulatory T cells

Acceleration of a Static Observer Near the Event Horizon of a Static Isolated Black Hole.

Science.gov (United States)

Doughty, Noel A.

1981-01-01

Compares the magnitude of the proper acceleration of a static observer in a static, isolated, spherically symmetric space-time region with the Newtonian result including the situation in the interior of a perfect-fluid star. This provides a simple physical interpretation of surface gravity and illustrates the global nature of the event horizon.…

Homotheties of cylindrically symmetric static spacetimes

International Nuclear Information System (INIS)

Qadir, A.; Ziad, M.; Sharif, M.

1998-08-01

In this note we consider the homotheties of cylindrically symmetric static spacetimes. We find that we can provide a complete list of all metrics that admit non-trivial homothetic motions and are cylindrically symmetric static. (author)

Finite element analysis of GFRP reinforced concrete pavement under static load

Science.gov (United States)

Li, Shiping; Hu, Chunhua

2018-02-01

GFRP was more corrosion resistant than traditional reinforced, it is lightweight, high strength thermal expansion coefficient is more close to the concrete and a poor conductor of electromagnetic. Therefore, the use of GFRP to replace the traditional reinforcement in concrete pavement application has excellent practical value. This paper uses ANSYS to establish delamination and reinforcement of Pavement model and analyzed response of GFRP concrete and ordinary concrete pavement structural mechanics on effects of different factors under the action of static. The results showed that under static load, pavement surface layer presented similar changes on stress of surface layer, vertical and horizontal deformation in two kinds of pavement structure, but indicators of GFRP reinforced concrete pavement were obviously better than that of ordinary concrete pavement.

Coupled cluster calculations for static and dynamic polarizabilities of C60

Science.gov (United States)

Kowalski, Karol; Hammond, Jeff R.; de Jong, Wibe A.; Sadlej, Andrzej J.

2008-12-01

New theoretical predictions for the static and frequency dependent polarizabilities of C60 are reported. Using the linear response coupled cluster approach with singles and doubles and a basis set especially designed to treat the molecular properties in external electric field, we obtained 82.20 and 83.62 Å3 for static and dynamic (λ =1064 nm) polarizabilities. These numbers are in a good agreement with experimentally inferred data of 76.5±8 and 79±4 Å3 [R. Antoine et al., J. Chem. Phys.110, 9771 (1999); A. Ballard et al., J. Chem. Phys.113, 5732 (2000)]. The reported results were obtained with the highest wave function-based level of theory ever applied to the C60 system.

T-cell activation and early gene response in dogs.

Directory of Open Access Journals (Sweden)

Sally-Anne Mortlock

Full Text Available T-cells play a crucial role in canine immunoregulation and defence against invading pathogens. Proliferation is fundamental to T-cell differentiation, homeostasis and immune response. Initiation of proliferation following receptor mediated stimuli requires a temporally programmed gene response that can be identified as immediate-early, mid- and late phases. The immediate-early response genes in T-cell activation engage the cell cycle machinery and promote subsequent gene activation events. Genes involved in this immediate-early response in dogs are yet to be identified. The present study was undertaken to characterise the early T-cell gene response in dogs to improve understanding of the genetic mechanisms regulating immune function. Gene expression profiles were characterised using canine gene expression microarrays and quantitative reverse transcription PCR (qRT-PCR, and paired samples from eleven dogs. Significant functional annotation clusters were identified following stimulation with phytohemagluttinin (PHA (5μg/ml, including the Toll-like receptor signaling pathway and phosphorylation pathways. Using strict statistical criteria, 13 individual genes were found to be differentially expressed, nine of which have ontologies that relate to proliferation and cell cycle control. These included, prostaglandin-endoperoxide synthase 2 (PTGS2/COX2, early growth response 1 (EGR1, growth arrest and DNA damage-inducible gene (GADD45B, phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1, V-FOS FBJ murine osteosarcoma viral oncogene homolog (FOS, early growth response 2 (EGR2, hemogen (HEMGN, polo-like kinase 2 (PLK2 and polo-like kinase 3 (PLK3. Differential gene expression was re-examined using qRT-PCR, which confirmed that EGR1, EGR2, PMAIP1, PTGS2, FOS and GADD45B were significantly upregulated in stimulated cells and ALAS2 downregulated. PTGS2 and EGR1 showed the highest levels of response in these dogs. Both of these genes are involved in

Modeling and Analysis of Static and Dynamic Characteristics of Nonlinear Seat Suspension for Off-Road Vehicles

Directory of Open Access Journals (Sweden)

Zhenhua Yan

2015-01-01

Full Text Available Low-frequency vibrations (0.5–5 Hz that harm drivers occur in off-road vehicles. Thus, researchers have focused on finding methods to effectively isolate or control low-frequency vibrations. A novel nonlinear seat suspension structure for off-road vehicles is designed, whose static characteristics and seat-human system dynamic response are modeled and analyzed, and experiments are conducted to verify the theoretical solutions. Results show that the stiffness of this nonlinear seat suspension could achieve real zero stiffness through well-matched parameters, and precompression of the main spring could change the nonlinear seat suspension performance when a driver’s weight changes. The displacement transmissibility curve corresponds with the static characteristic curve of nonlinear suspension, where the middle part of the static characteristic curve is gentler and the resonance frequency of the displacement transmissibility curve and the isolation minimum frequency are lower. Damping should correspond with static characteristics, in which the corresponding suspension damping value should be smaller given a flatter static characteristic curve to prevent vibration isolation performance reduction.

Individually programmable cell stretching microwell arrays actuated by a Braille display.

Science.gov (United States)

Kamotani, Yoko; Bersano-Begey, Tommaso; Kato, Nobuhiro; Tung, Yi-Chung; Huh, Dongeun; Song, Jonathan W; Takayama, Shuichi

2008-06-01

Cell culture systems are often static and are therefore nonphysiological. In vivo, many cells are exposed to dynamic surroundings that stimulate cellular responses in a process known as mechanotransduction. To recreate this environment, stretchable cell culture substrate systems have been developed, however, these systems are limited by being macroscopic and low throughput. We have developed a device consisting of 24 miniature cell stretching chambers with flexible bottom membranes that are deformed using the computer-controlled, piezoelectrically actuated pins of a Braille display. We have also developed efficient image capture and analysis protocols to quantify morphological responses of the cells to applied strain. Human dermal microvascular endothelial cells (HDMECs) were found to show increasing degrees of alignment and elongation perpendicular to the radial strain in response to cyclic stretch at increasing frequencies of 0.2, 1, and 5 Hz, after 2, 4, and 12h. Mouse myogenic C2C12 cells were also found to align in response to the stretch, while A549 human lung adenocarcinoma epithelial cells did not respond to stretch.

Thermal and metabolic responses of military divers during a 6-hour static dive in cold water.

Science.gov (United States)

Riera, Florence; Horr, Reed; Xu, Xiaojiang; Melin, Bruno; Regnard, Jacques; Bourdon, Lionel

2014-05-01

Human thermal responses during prolonged whole-body immersion in cold water are of interest for the military, especially French SEALS. This study aims at describing the thermo-physiological responses. There were 10 male military divers who were randomly assigned to a full immersion in neutral (34 degrees C), moderately cold (18 degrees C), and cold (10 degrees C) water wearing their operational protective devices (5.5 mm wetsuit with 3.0 mm thick underwear) for 6 h in a static position. Rectal temperature (T(re)) and 14 skin temperatures (T(sk)), blood analysis (stress biomarkers, metabolic substrates), and oxygen consumption (Vo2) were collected. At 34 degrees C, there were no significant modifications of the thermo-physiological responses over time. The most interesting result was that rates of rectal temperature decrease (0.15 +/- 0.02 degrees C x min(-1)) were the same between the two cold stress experimental conditions (at 18 degrees C and 10 degrees C). At the final experiment, rectal temperature was not significantly different between the two cold stress experimental conditions. Mean T(sk) decreased significantly during the first 3 h of immersion and then stabilized at a lower level at 10 degrees C (25.6 +/- 0.8 degrees C) than at 18 degrees C (29.3 +/- 0.9 degrees C). Other results demonstrate that the well-trained subjects developed effective physiological reactions. However, these reactions are consistently too low to counterbalance the heat losses induced by cold temperature conditions and long-duration immersion. This study shows that providing divers with thermal protection is efficient for a long-duration immersion from a medical point of view, but not from an operational one when skin extremities were taken into account.

Static strain-aging in commercial purity alpha titanium

International Nuclear Information System (INIS)

Donoso, J.R.; Reed-Hill, R.E.

1977-01-01

Static strain-aging was investigated in commercial purity α-Ti, containing 0.41 at. percent of oxygen as the principal interstitial impurity. 17 μM grain size specimens, prestrained to 0.02 strain at a nominal strain-rate of 3.3 x 10 -4 s -1 , were aged in situ between 555 and 630 0 K for lengths of time between 150 and 2.55 x 10 5 seconds. Both the upper and lower yield point increments were employed as measures of the aging progress. Under the stated conditions, the static strain-aging response of the titanium appeared to consist of four stages, of which only Stages 1 and 2 were considered in this work. Stage 1 corresponded to a Haasen and Kelly type of yield point, while Stage 2, after correcting for the time-independent yield point increment of Stage 1, conformed to Cottrell aging, i.e., the increase in flow stress after aging followed a t/sup 2 / 3 / behavior. The activation energy deduced for the process is in good agreement with that for the diffusion of oxygen in titanium

Mesenchymal stem cells induce dermal fibroblast responses to injury

International Nuclear Information System (INIS)

Smith, Andria N.; Willis, Elise; Chan, Vincent T.; Muffley, Lara A.; Isik, F. Frank; Gibran, Nicole S.; Hocking, Anne M.

2010-01-01

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury.

Innate lymphoid cells and their stromal microenvironments.

Science.gov (United States)

Kellermayer, Zoltán; Vojkovics, Dóra; Balogh, Péter

2017-09-01

In addition to the interaction between antigen presenting cells, T and B lymphocytes, recent studies have revealed important roles for a diverse set of auxiliary cells that profoundly influence the induction and regulation of immune responses against pathogens. Of these the stromal cells composed of various non-hematopoietic constituents are crucial for the creation and maintenance of specialized semi-static three-dimensional lymphoid tissue microenvironment, whereas the more recently described innate lymphoid cells are generated by the diversification of committed lymphoid precursor cells independently from clonally rearranged antigen receptor genes. Recent findings have revealed important contributions by innate lymphoid cells in inflammation and protection against pathogens in a tissue-specific manner. Importantly, lymphoid stromal cells also influence the onset of immune responses in tissue-specific fashion, raising the possibility of tissue-specific stromal - innate lymphoid cell collaboration. In this review we summarize the main features and interactions between these two cells types, with particular emphasis on ILC type 3 cells and their microenvironmental partners. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Tobacco and e-cigarette products initiate Kupffer cell inflammatory responses.

Science.gov (United States)

Rubenstein, David A; Hom, Sarah; Ghebrehiwet, Berhane; Yin, Wei

2015-10-01

Kupffer cells are liver resident macrophages that are responsible for screening and clearing blood of pathogens and foreign particles. It has recently been shown that Kupffer cells interact with platelets, through an adhesion based mechanism, to aid in pathogen clearance and then these platelets re-enter the general systemic circulation. Thus, a mechanism has been identified that relates liver inflammation to possible changes in the systemic circulation. However, the role that Kupffer cells play in cardiovascular disease initiation/progression has not been elucidated. Thus, our objective was to determine whether or not Kupffer cells are responsive to a classical cardiovascular risk factor and if these changes can be transmitted into the general systemic circulation. If Kupffer cells initiate inflammatory responses after exposure to classical cardiovascular risk factors, then this provides a potential alternative/synergistic pathway for cardiovascular disease initiation. We aimed to elucidate the prevalence of this potential pathway. We hypothesized that Kupffer cells would initiate a robust inflammatory response after exposure to tobacco cigarette or e-cigarette products and that the inflammatory response would have the potential to antagonize other salient cells for cardiovascular disease progression. To test this, Kupffer cells were incubated with tobacco smoke extracts, e-cigarette vapor extracts or pure nicotine. Complement deposition onto Kupffer cells, Kupffer cell complement receptor expression, oxidative stress production, cytokine release and viability and density were assessed after the exposure. We observed a robust inflammatory response, oxidative stress production and cytokine release after Kupffer cells were exposed to tobacco or e-cigarette extracts. We also observed a marginal decrease in cell viability coupled with a significant decrease in cell density. In general, this was not a function of the extract formulation (e.g. tobacco vs. e

Static resistance function for steel-plate composite (SC) walls subject to impactive loading

International Nuclear Information System (INIS)

Bruhl, Jakob C.; Varma, Amit H.; Kim, Joo Min

2015-01-01

Highlights: • An idealized static resistance function for SC walls is proposed. • The influence of design parameters on static resistance is explained. • SDOF models can accurately estimate global response of SC walls to missile impact. - Abstract: Steel-plate composite (SC) walls consist of a plain concrete core reinforced with two steel faceplates on the surfaces. Modules (consisting of steel faceplates, shear connectors and tie-bars) can be shop-fabricated and shipped to the site for erection and concrete casting, which expedites construction schedule and thus economy. SC structures have recently been used in nuclear power plant designs and are being considered for the next generation of small modular reactors. Design for impactive and impulsive loading is an important consideration for SC walls in safety-related nuclear facilities. The authors have previously developed design methods to prevent local failure (perforation) of SC walls due to missile impact. This paper presents the development of static resistance functions for use in single-degree-of-freedom (SDOF) analyses to predict the maximum displacement response of SC walls subjected to missile impact and designed to resist local failure (perforation). The static resistance function for SC walls is developed using results of numerical analyses and parametric studies conducted using benchmarked 3D finite element (FE) models. The influence of various design parameters are discussed and used to develop idealized bilinear resistance functions for SC walls with fixed edges and simply supported edges. Results from dynamic non-linear FE analysis of SC panels subjected to rigid missile impact are compared with the maximum displacements predicted by SDOF analyses using the bilinear resistance function.

Static resistance function for steel-plate composite (SC) walls subject to impactive loading

Energy Technology Data Exchange (ETDEWEB)

Bruhl, Jakob C., E-mail: jbruhl@purdue.edu; Varma, Amit H., E-mail: ahvarma@purdue.edu; Kim, Joo Min, E-mail: kim1493@purdue.edu

2015-12-15

Highlights: • An idealized static resistance function for SC walls is proposed. • The influence of design parameters on static resistance is explained. • SDOF models can accurately estimate global response of SC walls to missile impact. - Abstract: Steel-plate composite (SC) walls consist of a plain concrete core reinforced with two steel faceplates on the surfaces. Modules (consisting of steel faceplates, shear connectors and tie-bars) can be shop-fabricated and shipped to the site for erection and concrete casting, which expedites construction schedule and thus economy. SC structures have recently been used in nuclear power plant designs and are being considered for the next generation of small modular reactors. Design for impactive and impulsive loading is an important consideration for SC walls in safety-related nuclear facilities. The authors have previously developed design methods to prevent local failure (perforation) of SC walls due to missile impact. This paper presents the development of static resistance functions for use in single-degree-of-freedom (SDOF) analyses to predict the maximum displacement response of SC walls subjected to missile impact and designed to resist local failure (perforation). The static resistance function for SC walls is developed using results of numerical analyses and parametric studies conducted using benchmarked 3D finite element (FE) models. The influence of various design parameters are discussed and used to develop idealized bilinear resistance functions for SC walls with fixed edges and simply supported edges. Results from dynamic non-linear FE analysis of SC panels subjected to rigid missile impact are compared with the maximum displacements predicted by SDOF analyses using the bilinear resistance function.

Impact of Static Magnetic Field on the Antioxidant Defence System of Mice Fibroblasts

Directory of Open Access Journals (Sweden)

Marek Glinka

2018-01-01

Full Text Available Results of research assessing the biological impact of static magnetic fields are controversial. So far, they have not provided a clear answer to their influence on cell functioning. Since the use of permanent magnets both in everyday life and in industry becomes more and more widespread, the investigations are continued in order to explain these controversies and to evaluate positive applications. The goal of current work was to assess the impact of static magnetic field of different intensities on redox homeostasis in cultures of fibroblasts. The use of permanent magnets allowed avoiding the thermal effects which are present in electromagnets. During the research we used 6 chambers, designed exclusively by us, with different values of field flux density (varying from 0.1 to 0.7 T. We have noted the decrease in the activity of superoxide dismutase (SOD and glutathione peroxidase (GPx. The static magnetic fields did not modify the energy state of fibroblasts— adenosine triphosphate (ATP concentration was stable, as well as the generation of malondialdehyde (MDA—which is a marker of oxidative stress. Results of research suggest that static magnetic fields generated by permanent magnets do not cause oxidative stress in investigated fibroblasts and that they may show slight antioxidizing activity.

Adaptation and inhibition underlie responses to time-varying interaural phase cues in a model of inferior colliculus neurons.

Science.gov (United States)

Borisyuk, Alla; Semple, Malcolm N; Rinzel, John

2002-10-01

A mathematical model was developed for exploring the sensitivity of low-frequency inferior colliculus (IC) neurons to interaural phase disparity (IPD). The formulation involves a firing-rate-type model that does not include spikes per se. The model IC neuron receives IPD-tuned excitatory and inhibitory inputs (viewed as the output of a collection of cells in the medial superior olive). The model cell possesses cellular properties of firing rate adaptation and postinhibitory rebound (PIR). The descriptions of these mechanisms are biophysically reasonable, but only semi-quantitative. We seek to explain within a minimal model the experimentally observed mismatch between responses to IPD stimuli delivered dynamically and those delivered statically (McAlpine et al. 2000; Spitzer and Semple 1993). The model reproduces many features of the responses to static IPD presentations, binaural beat, and partial range sweep stimuli. These features include differences in responses to a stimulus presented in static or dynamic context: sharper tuning and phase shifts in response to binaural beats, and hysteresis and "rise-from-nowhere" in response to partial range sweeps. Our results suggest that dynamic response features are due to the structure of inputs and the presence of firing rate adaptation and PIR mechanism in IC cells, but do not depend on a specific biophysical mechanism. We demonstrate how the model's various components contribute to shaping the observed phenomena. For example, adaptation, PIR, and transmission delay shape phase advances and delays in responses to binaural beats, adaptation and PIR shape hysteresis in different ranges of IPD, and tuned inhibition underlies asymmetry in dynamic tuning properties. We also suggest experiments to test our modeling predictions: in vitro simulation of the binaural beat (phase advance at low beat frequencies, its dependence on firing rate), in vivo partial range sweep experiments (dependence of the hysteresis curve on

Comparing spatially static and dynamic vibrotactile take-over requests in the driver seat

NARCIS (Netherlands)

Petermeijer, S.M.; Cieler, S.; de Winter, J.C.F.

2017-01-01

Vibrotactile stimuli can be effective as warning signals, but their effectiveness as directional take-over requests in automated driving is yet unknown. This study aimed to investigate the correct response rate, reaction times, and eye and head orientation for static versus dynamic directional

Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

Science.gov (United States)

Zheng, Qi-Wen; Yu, Xue-Feng; Cui, Jiang-Wei; Guo, Qi; Ren, Di-Yuan; Cong, Zhong-Chao; Zhou, Hang

2014-10-01

Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device.

Static Einstein--Maxwell field equations

International Nuclear Information System (INIS)

Das, A.

1979-01-01

The static Einstein--Maxwell field equations are investigated in the presence of both electric and magnetic fields. The sources or bodies are assumed to be of finite size and to not affect the connectivity of the associated space. Furthermore, electromagnetic and metric fields are assumed to have reasonable differentiabilities. It is then proved that the electric and magnetic field vectors are constant multiples of one another. Moreover, the static Einstein--Maxwell equations reduce to the static magnetovac case. If, furthermore, the variational derivation of the Einstein--Maxwell equations is assumed, then both the total electric and magnetic charge of each body must vanish. As a physical consequence it is pointed out that if a suspended magnet be electrically charged then it must experience a purely general relativistic torque

Biomagnetic localization from transient quasi-static events

Energy Technology Data Exchange (ETDEWEB)

Mosher, J.C.; Leahy, R.M.; Lewis, P.S. [Los Alamos National Lab., NM (United States)]|[University of Southern California, Los Angeles, CA (United States). Signal and Image Processing Inst.

1993-02-01

Sensory stimuli, such as auditory, visual, or somatosensory, evoke neural responses in very localized regions of the brain. A SQUID biomagnetometer can measure the very weak fields that are generated outside of the head by this response. A simple source and head model of current dipoles inside a conducting sphere is typically used to interpret these magnetic field measurements or magnetoencephalogram (MEG). Locating dipole sources using data recorded from an array of biomagnetic sensors is distinguished from conventional array source localization techniques by the quasi-static transient nature of the data. Here, the basic MEG model is reviewed, then a localization example is given to motivate the need for partitioning the data to improve estimator performance. Tune-eigenspectrum analysis is introduced as a means of partitioning and interpreting spatio-temporal biomagnetic data. Examples using both simulated and somatosensory data are presented.

Biomagnetic localization from transient quasi-static events

Energy Technology Data Exchange (ETDEWEB)

Mosher, J.C.; Leahy, R.M.; Lewis, P.S. (Los Alamos National Lab., NM (United States) University of Southern California, Los Angeles, CA (United States). Signal and Image Processing Inst.)

1993-01-01

Sensory stimuli, such as auditory, visual, or somatosensory, evoke neural responses in very localized regions of the brain. A SQUID biomagnetometer can measure the very weak fields that are generated outside of the head by this response. A simple source and head model of current dipoles inside a conducting sphere is typically used to interpret these magnetic field measurements or magnetoencephalogram (MEG). Locating dipole sources using data recorded from an array of biomagnetic sensors is distinguished from conventional array source localization techniques by the quasi-static transient nature of the data. Here, the basic MEG model is reviewed, then a localization example is given to motivate the need for partitioning the data to improve estimator performance. Tune-eigenspectrum analysis is introduced as a means of partitioning and interpreting spatio-temporal biomagnetic data. Examples using both simulated and somatosensory data are presented.

Finite Element Modelling for Static and Free Vibration Response of Functionally Graded Beam

Directory of Open Access Journals (Sweden)

Ateeb Ahmad Khan

Full Text Available Abstract A 1D Finite Element model for static response and free vibration analysis of functionally graded material (FGM beam is presented in this work. The FE model is based on efficient zig-zag theory (ZIGT with two noded beam element having four degrees of freedom at each node. Linear interpolation is used for the axial displacement and cubic hermite interpolation is used for the deflection. Out of a large variety of FGM systems available, Al/SiC and Ni/Al2O3 metal/ceramic FGM system has been chosen. Modified rule of mixture (MROM is used to calculate the young's modulus and rule of mixture (ROM is used to calculate density and poisson's ratio of FGM beam at any point. The MATLAB code based on 1D FE zigzag theory for FGM elastic beams is developed. A 2D FE model for the same elastic FGM beam has been developed using ABAQUS software. An 8-node biquadratic plane stress quadrilateral type element is used for modeling in ABAQUS. Three different end conditions namely simply-supported, cantilever and clamped- clamped are considered. The deflection, normal stress and shear stress has been reported for various models used. Eigen Value problem using subspace iteration method is solved to obtain un-damped natural frequencies and the corresponding mode shapes. The results predicted by the 1D FE model have been compared with the 2D FE results and the results present in open literature. This proves the correctness of the model. Finally, mode shapes have also been plotted for various FGM systems.

Generation of TCR-Expressing Innate Lymphoid-like Helper Cells that Induce Cytotoxic T Cell-Mediated Anti-leukemic Cell Response.

Science.gov (United States)

Ueda, Norihiro; Uemura, Yasushi; Zhang, Rong; Kitayama, Shuichi; Iriguchi, Shoichi; Kawai, Yohei; Yasui, Yutaka; Tatsumi, Minako; Ueda, Tatsuki; Liu, Tian-Yi; Mizoro, Yasutaka; Okada, Chihiro; Watanabe, Akira; Nakanishi, Mahito; Senju, Satoru; Nishimura, Yasuharu; Kuzushima, Kiyotaka; Kiyoi, Hitoshi; Naoe, Tomoki; Kaneko, Shin

2018-06-05

CD4 + T helper (Th) cell activation is essential for inducing cytotoxic T lymphocyte (CTL) responses against malignancy. We reprogrammed a Th clone specific for chronic myelogenous leukemia (CML)-derived b3a2 peptide to pluripotency and re-differentiated the cells into original TCR-expressing T-lineage cells (iPS-T cells) with gene expression patterns resembling those of group 1 innate lymphoid cells. CD4 gene transduction into iPS-T cells enhanced b3a2 peptide-specific responses via b3a2 peptide-specific TCR. iPS-T cells upregulated CD40 ligand (CD40L) expression in response to interleukin-2 and interleukin-15. In the presence of Wilms tumor 1 (WT1) peptide, antigen-specific dendritic cells (DCs) conditioned by CD4-modified CD40L high iPS-T cells stimulated WT1-specific CTL priming, which eliminated WT1 peptide-expressing CML cells in vitro and in vivo. Thus, CD4 modification of CD40L high iPS-T cells generates innate lymphoid helper-like cells inducing bcr-abl-specific TCR signaling that mediates effectiveanti-leukemic CTL responses via DC maturation, showing potential for adjuvant immunotherapy against leukemia. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

'Static' octupole deformation

International Nuclear Information System (INIS)

Leander, G.A.

1985-01-01

Certain nuclei can be described as having intrinsic shapes with parity breaking static moments. The rationale for this description is discussed, spectroscopic models are outlined and their consequences are compared with experiment. (orig.)

Static Analysis of Mobile Programs

Science.gov (United States)

2017-02-01

and not allowed, to do. The second issue was that a fully static analysis was never a realistic possibility, because Java , the programming langauge...scale to large programs it had to handle essentially all of the features of Java and could also be used as a general-purpose analysis engine. The...static analysis of imperative languages. • A framework for adding specifications about the behavior of methods, including methods that were

Static Decoupling in fault detection

DEFF Research Database (Denmark)

Niemann, Hans Henrik

1998-01-01

An algebraic approach is given for a design of a static residual weighting factor in connection with fault detection. A complete parameterization is given of the weighting factor which will minimize a given performance index......An algebraic approach is given for a design of a static residual weighting factor in connection with fault detection. A complete parameterization is given of the weighting factor which will minimize a given performance index...

Synergy among rat T cells in the proliferative response to alloantigen

International Nuclear Information System (INIS)

Wright, P.W.; Loop, S.M.; Bernstein, I.D.

1979-01-01

A synergistic interaction in the proliferative response to alloantigen is described for mixtures of rat thymus and lymph node cells. The optimal conditions for synergy are quantitatively defined. Regression analysis of the slope of the dose-response curve has been utilized to estimate the degree of interaction in thymus--lymph node cell mixtures. The slope of the response of cell mixtures was noted to be significantly greater than the slope for the response of lympth node cells alone. Irradiation was shown to have a differential effect on the response of thymus and lymph node cells in mixtures. Irradiated thymus cells retained the capacity for synergy in mixtures, whereas irradiated lymph node cells did not. Additional studies have demonstrated that both de novo protein synthesis and specific antigen recognition by both responding cell populations in mixtures was required for maximal synergy. These studies demonstrate that synergy cannot be explained as an artifact of altered cell density in vitro. They establish that thymus cells and lymph node cells represent distinct subsets which manifest qualitatively different functions in the proliferative response to alloantigen. Thymus cells can respond directly to alloantigen by proliferation but also have the capacity to amplify the proliferative response of lymph node cells, a capacity which is resistant to X irradiation but requires recognition of alloantigen and de novo protein synthesis. Lymph node cells may similarly respond by proliferation to alloantigen but lack the amplifier activity of thymus cells. Synergy for rat lymphoidcells, like mouse lymphoid cells, has been shown to involve an interaction of thymus-derived lymphocytes

Cell response to surgery.

LENUS (Irish Health Repository)

Ni Choileain, Niamh

2012-02-03

OBJECTIVES: To describe the profound alterations in host immunity that are produced by major surgery as demonstrated by experimental and clinical studies, and to evaluate the benefits of therapeutic strategies aimed at attenuating perioperative immune dysfunction. DATA SOURCES: A review of the English-language literature was conducted, incorporating searches of the MEDLINE, EMBASE, and Cochrane collaboration databases to identify laboratory and clinical studies investigating the cellular response to surgery. STUDY SELECTION: Original articles and case reports describing immune dysfunction secondary to surgical trauma were included. DATA EXTRACTION: The results were compiled to show outcomes of different studies and were compared. DATA SYNTHESIS: Current evidence indicates that the early systemic inflammatory response syndrome observed after major surgery that is characterized by proinflammatory cytokine release, microcirculatory disturbance, and cell-mediated immune dysfunction is followed by a compensatory anti-inflammatory response syndrome, which predisposes the patient to opportunistic infection, multiple organ dysfunction syndrome, and death. Because there are currently no effective treatment options for multiple organ dysfunction syndrome, measures to prevent its onset should be initiated at an early stage. Accumulating experimental evidence suggests that targeted therapeutic strategies involving immunomodulatory agents such as interferon gamma, granulocyte colony-stimulating factor, the prostaglandin E(2) antagonist, indomethacin, and pentoxifylline may be used for the treatment of systemic inflammatory response syndrome to prevent the onset of multiple organ dysfunction syndrome. CONCLUSIONS: Surgical trauma produces profound immunological dysfunction. Therapeutic strategies directed at restoring immune homeostasis should aim to redress the physiological proinflammatory-anti-inflammatory cell imbalance associated with major surgery.

The slow cell death response when screening chemotherapeutic agents.

Science.gov (United States)

Blois, Joseph; Smith, Adam; Josephson, Lee

2011-09-01

To examine the correlation between cell death and a common surrogate of death used in screening assays, we compared cell death responses to those obtained with the sulforhodamine B (SRB) cell protein-based "cytotoxicity" assay. With the SRB assay, the Hill equation was used to obtain an IC50 and final cell mass, or cell mass present at infinite agent concentrations, with eight adherent cell lines and four agents (32 agent/cell combinations). Cells were treated with high agent concentrations (well above the SRB IC50) and the death response determined as the time-dependent decrease in cells failing to bind both annexin V and vital fluorochromes by flow cytometry. Death kinetics were categorized as fast (5/32) (similar to the reference nonadherent Jurkat line), slow (17/32), or none (10/32), despite positive responses in the SRB assay in all cases. With slow cell death, a single exposure to a chemotherapeutic agent caused a slow, progressive increase in dead (necrotic) and dying (apoptotic) cells for at least 72 h. Cell death (defined by annexin and/or fluorochrome binding) did not correlate with the standard SRB "cytotoxicity" assay. With the slow cell death response, a single exposure to an agent caused a slow conversion from vital to apoptotic and necrotic cells over at least 72 h (the longest time point examined). Here, increasing the time of exposure to agent concentrations modestly above the SRB IC50 provides a method of maximizing cell kill. If tumors respond similarly, sustained low doses of chemotherapeutic agents, rather than a log-kill, maximum tolerated dose strategy may be an optimal strategy of maximizing tumor cell death.

Survey of cell biology experiments in reduced gravity

Science.gov (United States)

Taylor, G. R.

1977-01-01

The effects of spaceflight on terrestrial cell systems are discussed. With some important exceptions, static cell systems carried aboard U.S.A. and U.S.S.R. space flights have failed to reveal space related anomalies. Some sophisticated devices which were developed for viewing directly, or continuously recording, the growth of cells, tissue cultures and eggs in flight, are described and the results summarized. The unique presence of high energy, multicharged (HZE) particles and full-range ultraviolet irradiation in space prompted evaluation of the response of single cells to these factors. Summary results and general conclusions are presented. Potential areas of research in future space flights are identified.

Induced pluripotent stem cells-derived myeloid-derived suppressor cells regulate the CD8+ T cell response

Directory of Open Access Journals (Sweden)

Daniel Joyce

2018-05-01

Full Text Available Myeloid-derived suppressor cells (MDSCs are markedly increased in cancer patients and tumor-bearing mice and promote tumor growth and survival by inhibiting host innate and adaptive immunity. In this study, we generated and characterized MDSCs from murine-induced pluripotent stem cells (iPSCs. The iPSCs were co-cultured with OP9 cells, stimulated with GM-CSF, and became morphologically heterologous under co-culturing with hepatic stellate cells. Allogeneic and OVA-specific antigen stimulation demonstrated that iPS-MDSCs have a T-cell regulatory function. Furthermore, a popliteal lymph node assay and autoimmune hepatitis model showed that iPS-MDSCs also regulate immune responsiveness in vivo and have a therapeutic effect against hepatitis. Taken together, our results demonstrated a method of generating functional MDSCs from iPSCs and highlighted the potential of iPS-MDSCs as a key cell therapy resource for transplantation and autoimmune diseases. Keywords: Myeloid-derived suppressor cells, Induced pluripotent stem cells, T cell response

T-cell-independent immune responses do not require CXC ligand 13-mediated B1 cell migration.

Science.gov (United States)

Colombo, Matthew J; Sun, Guizhi; Alugupalli, Kishore R

2010-09-01

The dynamic movement of B cells increases the probability of encountering specific antigen and facilitates cell-cell interactions required for mounting a rapid antibody response. B1a and B1b cells are enriched in the coelomic cavity, contribute to T-cell-independent (TI) antibody responses, and increase in number upon antigen exposure. B1 cell movement is largely governed by Cxc ligand 13 (Cxcl13), and mice deficient in this chemokine have a severe reduction in peritoneal B1 cells. In this study, we examined the role of Cxcl13-dependent B cell migration using Borrelia hermsii infection or intraperitoneal immunization with pneumococcal polysaccharide or 4-hydroxy-3-nitrophenyl-acetyl (NP)-Ficoll, all of which induce robust antibody responses from B1b cells. Surprisingly, we found that antibody responses to B. hermsii or to FhbA, an antigenic target of B1b cells, and the resolution of bacteremia were indistinguishable between wild-type and Cxcl13-/- mice. Importantly, we did not observe an expansion of peritoneal B1b cell numbers in Cxcl13-/- mice. Nonetheless, mice that had resolved infection were resistant to reinfection, indicating that the peritoneal B1b cell reservoir is not required for controlling B. hermsii. Furthermore, despite a reduced peritoneal B1b compartment, immunization with pneumococcal polysaccharide vaccine yielded comparable antigen-specific antibody responses in wild-type and Cxcl13-/- mice and conferred protection against Streptococcus pneumoniae. Likewise, immunization with NP-Ficoll elicited similar antibody responses in wild-type and Cxcl13-/- mice. These data demonstrate that homing of B1 cells into the coelomic cavity is not a requirement for generating protective TI antibody responses, even when antigen is initially localized to this anatomical compartment.

Artifactual voltage response recorded from hair cells with patch-clamp amplifiers.

Science.gov (United States)

Masetto, S; Weng, T; Valli, P; Correia, M J

1999-06-23

Patch-clamp amplifiers (PCAs) are commonly used to characterize voltage- and current-clamp responses in the same cell. However, the cell membrane voltage response can be severely distorted by PCAs working in the current-clamp mode. Here we compare the voltage response of pigeon semicircular canal hair cells in situ, recorded with two different PCAs, and with a classic microelectrode bridge amplifier (BA). We found that the voltage response of hair cells recorded with PCAs differed significantly from that recorded with the BA. The true hair cell membrane voltage response to positive current steps was characterized by a strongly damped oscillation, whose frequency and duration depended on hair cell location in the sensory crista ampullaris.

Literature review Quasi-static and Dynamic pile load tests : Primarily report on non-static pile load tests

NARCIS (Netherlands)

Huy, N.Q.

2010-01-01

Pile testing, which plays an importance role in the field of deep foundation design, is performed by static and non-static methods to provide information about the following issues: (Poulos, 1998) - The ultimate capacity of a single pile. - The load-displacement behavior of a pile. - The performance

Static Analysis for JavaScript

DEFF Research Database (Denmark)

Jensen, Simon Holm

. This dissertation describes the design and implementation of a static analysis for JavaScript that can assist programmers in finding bugs in code during development. We describe the design of a static analysis tool for JavaScript, built using the monotone framework. This analysis infers detailed type information......Web applications present unique challenges to designers of static analysis tools. One of these challenges is the language JavaScript used for client side scripting in the browser. JavaScript is a complex language with many pitfalls and poor tool support compared to other languages...... about programs. This information can be used to detect bugs such as null pointer dereferences and unintended type coercions. The analysis is sound, enabling it to prove the absence of certain program errors. JavaScript is usually run within the context of the browser and the DOM API. The major...

Evaluation and optimization of the bandwidth of static converters: application to multi-cell converters; Evaluation et optimisation de la bande passante des convertisseurs statiques

Energy Technology Data Exchange (ETDEWEB)

Aime, M.

2003-11-15

Thanks to the technological progress achieved in the field of power electronics, the use of static converters has spread to new applications. In particular, some applications such as active filtering or the supply of special AC machines require power converters having good dynamic performances. The subject of this thesis is to evaluate systematically the dynamic performances of multi-cell converters, and then to optimize these performances. This document is organized in four chapters. The first one summarizes the main multilevel converter structures, and some control strategies dedicated to these structures. The second chapter presents the evaluation criteria chosen to quantify the dynamic performances of static converters. These criteria are then used to compare the performances obtained with two different PWM strategies. An optimized strategy which results from a trade-off between the two former strategies is then introduced. The third chapter shows a new control strategy of multi-cell voltage source converters. This new strategy enables to control the peak current at a fixed switching frequency. The operation of this controller is explained, and the results obtained by digital simulations are presented and discussed. The fourth chapter deals with the experimental achievement of the peak current control. In particular, the implementation of the control algorithm within a FPGA is demonstrated. Finally, the conclusion of this thesis presents some orientations for further developments, in order to improve the current control strategy and to widen its field of applications. (author)

Structural Analysis of Cabinet Support under Static and Seismic Loads

International Nuclear Information System (INIS)

Jung, Kwangsub; Lee, Sangjin; Oh, Jinho

2014-01-01

The cabinet support consists of frames including steel channels and steel square tubes. Four tap holes for screw bolts are located on the support frame of a steel channel to fix the cabinet on the support. The channels and square tubes are assembled by welded joints. The cabinet supports are installed on the outer walls of the reactor concrete island. The KEPIC code, MNF, is used for the design of the cabinet support. In this work, the structural integrity of the cabinet support is analyzed under consideration of static and seismic loads. A 3-D finite element model of the cabinet support was developed. The structural integrity of the cabinet support under postulated service loading conditions was evaluated through a static analysis, modal analysis, and response spectrum analysis. From the structural analysis results, it was concluded that the structural integrity of the cabinet support is guaranteed

Respiratory epithelial cell responses to cigarette smoke: the unfolded protein response.

Science.gov (United States)

Kelsen, Steven G

2012-12-01

Cigarette smoking exposes the respiratory epithelium to highly toxic, reactive oxygen nitrogen species which damage lung proteins in the endoplasmic reticulum (ER), the cell organelle in which all secreted and membrane proteins are processed. Accumulation of damaged or misfolded proteins in the ER, a condition termed ER stress, activates a complex cellular process termed the unfolded protein responses (UPR). The UPR acts to restore cellular protein homeostasis by regulating all aspects of protein metabolism including: protein translation and syntheses; protein folding; and protein degradation. However, activation of the UPR may also induce signaling pathways which induce inflammation and cell apoptosis. This review discusses the role of UPR in the respiratory epithelial cell response to cigarette smoke and the pathogenesis of lung diseases like COPD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Static analysis of large-scale multibody system using joint coordinates and spatial algebra operator.

Science.gov (United States)

Omar, Mohamed A

2014-01-01

Initial transient oscillations inhibited in the dynamic simulations responses of multibody systems can lead to inaccurate results, unrealistic load prediction, or simulation failure. These transients could result from incompatible initial conditions, initial constraints violation, and inadequate kinematic assembly. Performing static equilibrium analysis before the dynamic simulation can eliminate these transients and lead to stable simulation. Most exiting multibody formulations determine the static equilibrium position by minimizing the system potential energy. This paper presents a new general purpose approach for solving the static equilibrium in large-scale articulated multibody. The proposed approach introduces an energy drainage mechanism based on Baumgarte constraint stabilization approach to determine the static equilibrium position. The spatial algebra operator is used to express the kinematic and dynamic equations of the closed-loop multibody system. The proposed multibody system formulation utilizes the joint coordinates and modal elastic coordinates as the system generalized coordinates. The recursive nonlinear equations of motion are formulated using the Cartesian coordinates and the joint coordinates to form an augmented set of differential algebraic equations. Then system connectivity matrix is derived from the system topological relations and used to project the Cartesian quantities into the joint subspace leading to minimum set of differential equations.

B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction.

Science.gov (United States)

Shin, Jung Hoon; Park, Se-Ho

2013-10-01

CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although α-galactosylceramide (α-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-γ by NKT cells, concomitant with a decreased level of IL-4, in the circumstance of co-culture of DCs and B Cells. Remarkably, the response promoted by B cells was dependent on CD1d expression of B cells.

Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

International Nuclear Information System (INIS)

Zheng Qi-Wen; Yu Xue-Feng; Cui Jiang-Wei; Guo Qi; Ren Di-Yuan; Cong Zhong-Chao; Zhou Hang

2014-01-01

Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device. (condensed matter: structural, mechanical, and thermal properties)

Modeling of static characteristics of switched reluctance motor

International Nuclear Information System (INIS)

Asgharmemon, A.; Hussain, I.; Daudpoto, J.

2013-01-01

To investigate the running characteristics of a switched reluctance motor, the static characteristics and related input data tables are required. The static characteristics comprise of flux linkage, co-energy and static torque characteristics. The co-energy and static torque are calculated once data of magnetization characteristics is available. The data of co-energy is required for the calculation of static torque characteristics. The simulation model includes the data of static characteristics for prediction of the instantaneous and steady state performance of the motor. In this research a computer based procedure of experiments is carried out for measurement of the magnetization characteristics. For every set of measurements, the removal of eddy current is carefully addressed. The experiments are carried out on an existing 8/6 pole rotary switched reluctance motor. Additionally, the instantaneous phase current, instantaneous torque and flux waveforms are produced by using linear, which is by default and spline data interpolation separately. The information obtained from theses simulation results will help in an improved simulation model for predicting the performance of the machine. (author)

Collapse mechanisms of metal foam matrix composites under static and dynamic loading conditions

Energy Technology Data Exchange (ETDEWEB)

Linul, Emanoil, E-mail: emanoil.linul@upt.ro [Department of Mechanics and Strength of Materials, Politehnica University of Timisoara, 1 Mihai Viteazu Avenue, 300 222 Timisoara (Romania); Marsavina, Liviu [Department of Mechanics and Strength of Materials, Politehnica University of Timisoara, 1 Mihai Viteazu Avenue, 300 222 Timisoara (Romania); Kováčik, Jaroslav [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 13 Bratislava (Slovakia)

2017-04-06

The collapse mechanisms of metal foam matrix composites under static and dynamic loading conditions were experimentally and analytically investigated. Closed-cell aluminium foam AlSi10 with 325±10 kg/m{sup 3} density was used as core material, while stainless-steel-mesh is the faces materials. Prior to characterizing the composite sandwich structure, the stainless steel mesh face material and closed-cell aluminium foam were characterized by tensile testing and compression testing, respectively. Experimental tests were performed on sandwich beams using both High Speed Camera and Digital Image Correlation system for strain distribution. All experimental tests were performed at room temperature with constant crosshead speed of 1.67×10{sup −4} m/s for static tests and 2 m/s impact loading speed for dynamic tests. Two main deformation behaviours of investigated metal foam matrix composites were observed following post-failure collapse: face failure and core shear. It was showed that the initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical parameters.

Temporal Analyses of the Response of Intervertebral Disc Cells and Mesenchymal Stem Cells to Nutrient Deprivation

Directory of Open Access Journals (Sweden)

Sarah A. Turner

2016-01-01

Full Text Available Much emphasis has been placed recently on the repair of degenerate discs using implanted cells, such as disc cells or bone marrow derived mesenchymal stem cells (MSCs. This study examines the temporal response of bovine and human nucleus pulposus (NP cells and MSCs cultured in monolayer following exposure to altered levels of glucose (0, 3.15, and 4.5 g/L and foetal bovine serum (0, 10, and 20% using an automated time-lapse imaging system. NP cells were also exposed to the cell death inducers, hydrogen peroxide and staurosporine, in comparison to serum starvation. We have demonstrated that human NP cells show an initial “shock” response to reduced nutrition (glucose. However, as time progresses, NP cells supplemented with serum recover with minimal evidence of cell death. Human NP cells show no evidence of proliferation in response to nutrient supplementation, whereas MSCs showed greater response to increased nutrition. When specifically inducing NP cell death with hydrogen peroxide and staurosporine, as expected, the cell number declined. These results support the concept that implanted NP cells or MSCs may be capable of survival in the nutrient-poor environment of the degenerate human disc, which has important clinical implications for the development of IVD cell therapies.

The Role of B Cells for in Vivo T Cell Responses to a Friend Virus-Induced Leukemia

Science.gov (United States)

Schultz, Kirk R.; Klarnet, Jay P.; Gieni, Randall S.; Hayglass, Kent T.; Greenberg, Philip D.

1990-08-01

B cells can function as antigen-presenting cells and accessory cells for T cell responses. This study evaluated the role of B cells in the induction of protective T cell immunity to a Friend murine leukemia virus (F-MuLV)-induced leukemia (FBL). B cell-deficient mice exhibited significantly reduced tumor-specific CD4^+ helper and CD8^+ cytotoxic T cell responses after priming with FBL or a recombinant vaccinia virus containing F-MuLV antigens. Moreover, these mice had diminished T cell responses to the vaccinia viral antigens. Tumor-primed T cells transferred into B cell-deficient mice effectively eradicated disseminated FBL. Thus, B cells appear necessary for efficient priming but not expression of tumor and viral T cell immunity.

Phagocytic response of astrocytes to damaged neighboring cells.

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Nicole M Wakida

Full Text Available This study aims to understand the phagocytic response of astrocytes to the injury of neurons or other astrocytes at the single cell level. Laser nanosurgery was used to damage individual cells in both primary mouse cortical astrocytes and an established astrocyte cell line. In both cases, the release of material/substances from laser-irradiated astrocytes or neurons induced a phagocytic response in near-by astrocytes. Propidium iodide stained DNA originating from irradiated cells was visible in vesicles of neighboring cells, confirming phagocytosis of material from damaged cortical cells. In the presence of an intracellular pH indicator dye, newly formed vesicles correspond to acidic pH fluorescence, thus suggesting lysosome bound degradation of cellular debris. Cells with shared membrane connections prior to laser damage had a significantly higher frequency of induced phagocytosis compared to isolated cells with no shared membrane. The increase in phagocytic response of cells with a shared membrane occurred regardless of the extent of shared membrane (a thin filopodial connection vs. a cell cluster with significant shared membrane. In addition to the presence (or lack of a membrane connection, variation in phagocytic ability was also observed with differences in injury location within the cell and distance separating isolated astrocytes. These results demonstrate the ability of an astrocyte to respond to the damage of a single cell, be it another astrocyte, or a neuron. This single-cell level of analysis results in a better understanding of the role of astrocytes to maintain homeostasis in the CNS, particularly in the sensing and removal of debris in damaged or pathologic nervous tissue.

Healthy human T-Cell Responses to Aspergillus fumigatus antigens.

Directory of Open Access Journals (Sweden)

Neelkamal Chaudhary

2010-02-01

Full Text Available Aspergillus fumigatus is associated with both invasive and allergic pulmonary diseases, in different hosts. The organism is inhaled as a spore, which, if not cleared from the airway, germinates into hyphal morphotypes that are responsible for tissue invasion and resultant inflammation. Hyphae secrete multiple products that function as antigens, evoking both a protective (T(H1-T(H17 and destructive allergic (T(H2 immunity. How Aspergillus allergens (Asp f proteins participate in the development of allergic sensitization is unknown.To determine whether Asp f proteins are strictly associated with T(H2 responses, or represent soluble hyphal products recognized by healthy hosts, human T cell responses to crude and recombinant products were characterized by ELISPOT. While responses (number of spots producing IFN-gamma, IL-4 or IL-17 to crude hyphal antigen preparations were weak, responses to recombinant Asp f proteins were higher. Recombinant allergens stimulated cells to produce IFN-gamma more so than IL-4 or IL-17. Volunteers exhibited a diverse CD4+ and CD8+ T cell antigen recognition profile, with prominent CD4 T(H1-responses to Asp f3 (a putative peroxismal membrane protein, Asp f9/16 (cell wall glucanase, Asp f11 (cyclophilin type peptidyl-prolyl isomerase and Asp f22 (enolase. Strong IFN-gamma responses were reproduced in most subjects tested over 6 month intervals.Products secreted after conidial germination into hyphae are differentially recognized by protective T cells in healthy, non-atopic individuals. Defining the specificity of the human T cell repertoire, and identifying factors that govern early responses may allow for development of novel diagnostics and therapeutics for both invasive and allergic Aspergillus diseases.

Topological characterization of static strain aging of type AISI 304 austenitic stainless steel

International Nuclear Information System (INIS)

Monteiro, S.N.; Miranda, P.E.V. de

1981-01-01

Static strain aging of type AISI 304 austenitic stainless steel was studied from room temperature up to 623K by conducting tests in which the load was held approximately constant. The aging times varied between 10s and 100h, using a plastic pre-deformation of 9%. The static strain aging of 304 steel furnished an activation energy of 23.800 cal/mol. This implies that vacancies play an important role on the aging process. The curve of the variation of the discontinuous yielding with aging time presented different stages, to which specific mathematical expressions were developed. These facts permited the conclusion that Snock type mechanisms are responsible for the aging in such conditions. (Author) [pt

Static recrystallisation and precipitation after hot deformation of austenitic stainless steels containing molybdenum and niobium

International Nuclear Information System (INIS)

Lombry, R.; Rossard, C.; Thomas, B.J.

1981-01-01

In general the hot workability of austenite depends on the work hardening during deformation and the kinetics of the dynamic and static restoration processes. Static recrystallisation is a very important factor in the case of hot rolling. The present work was undertaken to determine the effect of additions of molybdenum or niobium on the kinetics of static recrystallisation. The results show that the rate of static recrystallisation of type 304, 316 and 347 stainless steels decreases in this order for a given amount of prior deformation (epsilon=0,44). The differences in the rates of recrystallisation increases as the temperature is lowered towards 900 deg C. The effect of molybdenum appears to be attribuable to a solute drag effect on the mobility of dislocations, subgrain boundaries or grain boundaries whereas niobium additions lead to the formation of NbC precipitates on the dislocation cell walls and sub boundaries. It is also shown that in the case of type 316 and type 347 steels the dynamic recrystallisation process (observed in type 304 steels at all temperatures above 900 deg C) is replaced by dynamic recovery at temperatures egal to or below about 1000 deg C [fr

Touching force response of the piezoelectric Braille cell.

Science.gov (United States)

Smithmaitrie, Pruittikorn; Kanjantoe, Jinda; Tandayya, Pichaya

2008-11-01

The objective of this research is to investigate dynamic responses of the piezoelectric Braille cell when it is subjected to both electrical signal and touching force. Physical behavior of the piezoelectric actuator inside the piezoelectric Braille cell is analyzed. The mathematical model of the piezoelectric Braille system is presented. Then, data of visually impaired people using a Braille Note is studied as design information and a reference input for calculation of the piezoelectric Braille response under the touching force. The results show dynamic responses of the piezoelectric Braille cell. The designed piezoelectric bimorph has a settling time of 0.15 second. The relationship between the Braille dot height and applied voltage is linear. The behavior of the piezoelectric Braille dot when it is touched during operation shows that the dot height is decreased as the force increases. The result provides understanding of the piezoelectric Braille cell behavior under both touching force and electrical excitation simultaneously. This is the important issue for the design and development of piezoelectric Braille cells in senses of controlling Braille dot displacement or force-feedback in the future.

Neurocognitive responses to a single session of static squats with whole body vibration.

Science.gov (United States)

Amonette, William E; Boyle, Mandy; Psarakis, Maria B; Barker, Jennifer; Dupler, Terry L; Ott, Summer D

2015-01-01

The purpose of this study was to determine if the head accelerations using a common whole body vibration (WBV) exercise protocol acutely reduced neurocognition in healthy subjects. Second, we investigated differential responses to WBV plates with 2 different delivery mechanisms: vertical and rotational vibrations. Twelve healthy subjects (N = 12) volunteered and completed a baseline (BASE) neurocognitive assessment: the Immediate Postconcussion Assessment and Cognitive Test (ImPACT). Subjects then participated in 3 randomized exercise sessions separated by no more than 2 weeks. The exercise sessions consisted of five 2-minute sets of static hip-width stance squats, with the knees positioned at a 45° angle of flexion. The squats were performed with no vibration (control [CON]), with a vertically vibrating plate (vertical vibration [VV]), and with a rotational vibrating plate (rotational vibration [RV]) set to 30 Hz with 4 mm of peak-to-peak displacement. The ImPACT assessments were completed immediately after each exercise session and the composite score for 5 cognitive domains was analyzed: verbal memory, visual memory, visual motor speed, reaction time, and impulse control. Verbal memory scores were unaffected by exercise with or without vibration (p = 0.40). Likewise, visual memory was not different (p = 0.14) after CON, VV, or RV. Significant differences were detected for visual motor speed (p = 0.006); VV was elevated compared with BASE (p = 0.01). There were no significant differences (p = 0.26) in reaction time or impulse control (p = 0.16) after exercise with or without vibration. In healthy individuals, 10 minutes of 30 Hz, 4-mm peak-to-peak displacement vibration exposure with a 45° angle of knee flexion did not negatively affect neurocognition.

Static and dynamic strain energy release rates in toughened thermosetting composite laminates

Science.gov (United States)

Cairns, Douglas S.

1992-01-01

In this work, the static and dynamic fracture properties of several thermosetting resin based composite laminates are presented. Two classes of materials are explored. These are homogeneous, thermosetting resins and toughened, multi-phase, thermosetting resin systems. Multi-phase resin materials have shown enhancement over homogenous materials with respect to damage resistance. The development of new dynamic tests are presented for composite laminates based on Width Tapered Double Cantilevered Beam (WTDCB) for Mode 1 fracture and the End Notched Flexure (ENF) specimen. The WTDCB sample was loaded via a low inertia, pneumatic cylinder to produce rapid cross-head displacements. A high rate, piezo-electric load cell and an accelerometer were mounted on the specimen. A digital oscilloscope was used for data acquisition. Typical static and dynamic load versus displacement plots are presented. The ENF specimen was impacted in three point bending with an instrumented impact tower. Fracture initiation and propagation energies under static and dynamic conditions were determined analytically and experimentally. The test results for Mode 1 fracture are relatively insensitive to strain rate effects for the laminates tested in this study. The test results from Mode 2 fracture indicate that the toughened systems provide superior fracture initiation and higher resistance to propagation under dynamic conditions. While the static fracture properties of the homogeneous systems may be relatively high, the apparent Mode 2 dynamic critical strain energy release rate drops significantly. The results indicate that static Mode 2 fracture testing is inadequate for determining the fracture performance of composite structures subjected to conditions such as low velocity impact. A good correlation between the basic Mode 2 dynamic fracture properties and the performance is a combined material/structural Compression After Impact (CAI) test is found. These results underscore the importance of

Bacterial CpG-DNA activates dendritic cells in vivo: T helper cell-independent cytotoxic T cell responses to soluble proteins.

Science.gov (United States)

Sparwasser, T; Vabulas, R M; Villmow, B; Lipford, G B; Wagner, H

2000-12-01

Receptors for conserved molecular patterns associated with microbial pathogens induce synthesis of co-stimulatory molecules and cytokines in immature dendritic cells (DC), as do antigen-reactive CD4 T helper cells via CD40 signaling. Once activated, antigen-presenting DC may activate CD8 T cell responses in a T helper cell-independent fashion. Using immunostimulatory CpG-oligonucleotides (ODN) mimicking bacterial CpG-DNA, we tested whether CpG-DNA bypasses the need for T helper cells in CTL responses towards proteins by directly activating antigen-presenting DC to transit into professional APC. We describe that immature DC in situ constitutively process soluble proteins and generate CD8 T cell determinants yet CD8 T cell responses remain abortive. Induction of primary antigen-specific CD8 cytotoxic T lymphocyte (CTL)-mediated responses becomes initiated in wild-type as well as T helper cell-deficient mice, provided soluble protein and CpG-ODN are draining into the same lymph node. Specifically we show that CpG-ODN trigger antigen-presenting immature DC within the draining lymph node to acutely up-regulate co-stimulatory molecules and produce IL-12. These results provide new insights for generating in vivo efficient CTL responses to soluble proteins which may influence vaccination strategies.

Static states and dynamic behaviour of charges: observation and control by scanning probe microscopy

International Nuclear Information System (INIS)

Ishii, Masashi

2010-01-01

This paper reviews charges that locally functionalize materials. Microscopic analyses and operation of charges using various scanning probe microscopy (SPM) techniques have revealed static, quasi-static/quasi-dynamic and dynamic charge behaviours. Charge-sensitive SPM has allowed for the visualization of the distribution of functionalized charges in electronic devices. When used as bit data in a memory system, the charges can be operated by SPM. The behaviour of quasi-static/quasi-dynamic charges is discussed here. In the data-writing process, spatially dispersive charges rather than a fast injection rate are introduced, but the technical problems can be solved by using nanostructures. Careful charge operations using SPM should realize a memory with a larger density than Tbit/inch 2 . Dynamic charges have been introduced in physical analyses and chemical processes. Although the observable timescale is limited by the SPM system response time of the order of several seconds, dynamics such as photon-induced charge redistributions and probe-assisted chemical reactions are observed. (topical review)

Static states and dynamic behaviour of charges: observation and control by scanning probe microscopy

Energy Technology Data Exchange (ETDEWEB)

Ishii, Masashi, E-mail: ISHII.Masashi@nims.go.j [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

2010-05-05

This paper reviews charges that locally functionalize materials. Microscopic analyses and operation of charges using various scanning probe microscopy (SPM) techniques have revealed static, quasi-static/quasi-dynamic and dynamic charge behaviours. Charge-sensitive SPM has allowed for the visualization of the distribution of functionalized charges in electronic devices. When used as bit data in a memory system, the charges can be operated by SPM. The behaviour of quasi-static/quasi-dynamic charges is discussed here. In the data-writing process, spatially dispersive charges rather than a fast injection rate are introduced, but the technical problems can be solved by using nanostructures. Careful charge operations using SPM should realize a memory with a larger density than Tbit/inch{sup 2}. Dynamic charges have been introduced in physical analyses and chemical processes. Although the observable timescale is limited by the SPM system response time of the order of several seconds, dynamics such as photon-induced charge redistributions and probe-assisted chemical reactions are observed. (topical review)

Studies on adaptive responses in Chinese hamster cells

International Nuclear Information System (INIS)

Michelin, S.C.; Perez, M.R. Del; Dubner, D.; Gisone, P.A.

1997-01-01

For many years the possibility has been considered of low doses of radiation inducing adaptive responses in cells and organisms against the mutagenic effects of radiation. Currently, a number of experimental data appraise the existence of an adaptive response that is characterized by a decrease of radiation induced genetic damages. The understanding of the molecular mechanism involved in this phenomenon permits to estimate the effects and risks of low dose exposure. In this work, preliminary results of studies on the induction of adaptive response in cells subjected to different doses of ionizing radiation are presented

Statics of historic masonry constructions

CERN Document Server

Como, Mario

2017-01-01

Masonry constructions are the great majority of the buildings in Europe’s historic centres and the most important monuments of its architectural heritage. Given the age of these constructions, the demand for safety assessments and restoration projects is pressing and constant; still within the broad studies in the subject it is not yet recognised, in particular within the seismic area, a unitary approach to deal with Masonry structures. This successful book contributes to clarify the issues with a rigorous approach offering a comprehensive new Statics of Masonry Constructions. This third edition has been driven by some recent developments of the research in the field, and it gives the fundamentals of Statics with an original and rigorous mathematical formulation, further in-depth inquired in this new version. With many refinements and improvements, the book investigates the static behaviour of many historic monuments, such as the Gothic Cathedrals, the Mycenaean Tholoi, the Pantheon, the Colosseum, the dome...

A study of microstructure, quasi-static response, fatigue, deformation and fracture behavior of high strength alloy steels

Science.gov (United States)

Kannan, Manigandan

The history of steel dates back to the 17th century and has been instrumental in the betterment of every aspect of our lives ever since, from the pin that holds the paper together to the Automobile that takes us to our destination steel touches everyone every day. Path breaking improvements in manufacturing techniques, access to advanced machinery and understanding of factors like heat treatment, corrosion resistance have aided in the advancement in the properties of steel in the last few years. In this dissertation document, the results of a study aimed at the influence of alloy chemistry, processing and influence of the quasi static and fatigue behavior of seven alloy steels is discussed. The microstructure of the as-received steel was examined and characterized for the nature and morphology of the grains and the presence of other intrinsic features in the microstructure. The tensile, cyclic fatigue and bending fatigue tests were done on a fully automated closed-loop servo-hydraulic test machine at room temperature. The failed samples of high strength steels were examined in a scanning electron microscope for understanding the fracture behavior, especially the nature of loading be it quasi static, cyclic fatigue or bending fatigue . The quasi static and cyclic fatigue fracture behavior of the steels examined coupled with various factors contributing to failure are briefly discussed in light of the conjoint and mutually interactive influences of intrinsic microstructural effects, nature of loading, and stress (load)-deformation-microstructural interactions.

Intracellular proteins produced by mammalian cells in response to environmental stress

Science.gov (United States)

Goochee, Charles F.; Passini, Cheryl A.

1988-01-01

The nature of the response of mammalian cells to environmental stress is examined by reviewing results of studies where cultured mouse L cells and baby hamster kidney cells were exposed to heat shock and the synthesis of heat-shock proteins and stress-response proteins (including HSP70, HSC70, HSP90, ubiquitin, and GRP70) in stressed and unstressed cells was evaluated using 2D-PAGE. The intracellular roles of the individual stress response proteins are discussed together with the regulation of the stress response system.

Non-local means filter for trim statics

KAUST Repository

Huang, Yunsong; Wang, Xin; Schuster, Gerard T.

2014-01-01

this problem, we propose a trim statics inspired by the non-local means algorithm originally developed for image denoising. This method differs from the conventional one in two fundamental respects. First, the trim statics are computed by comparing image

Static Feed Water Electrolysis Subsystem Testing and Component Development

Science.gov (United States)

Koszenski, E. P.; Schubert, F. H.; Burke, K. A.

1983-01-01

A program was carried out to develop and test advanced electrochemical cells/modules and critical electromechanical components for a static feed (alkaline electrolyte) water electrolysis oxygen generation subsystem. The accomplishments were refurbishment of a previously developed subsystem and successful demonstration for a total of 2980 hours of normal operation; achievement of sustained one-person level oxygen generation performance with state-of-the-art cell voltages averaging 1.61 V at 191 ASF for an operating temperature of 128F (equivalent to 1.51V when normalized to 180F); endurance testing and demonstration of reliable performance of the three-fluid pressure controller for 8650 hours; design and development of a fluid control assembly for this subsystem and demonstration of its performance; development and demonstration at the single cell and module levels of a unitized core composite cell that provides expanded differential pressure tolerance capability; fabrication and evaluation of a feed water electrolyte elimination five-cell module; and successful demonstration of an electrolysis module pressurization technique that can be used in place of nitrogen gas during the standby mode of operation to maintain system pressure and differential pressures.

Responses of macaque ganglion cells to far violet lights

International Nuclear Information System (INIS)

De Monasterio, F.M.; Gouras, P.

1977-01-01

In a sample of 487 colour-opponent ganglion cells recorded in the central retina of the rhesus and cynomolgus monkeys, 9% of these neurones were found to have responses with the same sign at both ends of the visible spectrum mediated by red-sensitive cones and mid-spectral responses of opposite sign mediated by green-sensitive cones. Selective chromatic adaptation showed that the responses to far violet lights (400 to 420 nm) were due to input from red- and not blue-sensitive cones. These responses were enhanced by backgrounds depressing the sensitivity of blue- and green-sensitive cones and they were depressed by backgrounds depressing the sensitivity of red-sensitive cones; the sensitivity of these responses was yoked to that of responses to far red lights. The relative incidence of these ganglion cells was maximal at the foveal region and decreased towards the peripheral retina. The properties of these cells are consistent with some psychophysical observations of human vision at the short wave-lengths. (author)

THE EFFECT OF THE STATIC RELATIVE STRENGTH ON THE MAXIMUM RELATIVE RECEIVING OF OXYGEN

Directory of Open Access Journals (Sweden)

Abdulla Elezi

2011-09-01

Full Text Available Based on research on the sample of 263 students of age- 18 years, and used batteries of 9 tests for evaluation of the static relative strength and the criterion variable- maximum relative receiving of oxygen (VO2 ml / kg / min based on the Astrand test ,and on regression analysis to determine the influence of the static relative strength on the criterion variable maximum relative oxygen receiving, can be generally concluded that from 9 predictor variables statistically significant partial effect have 2variables. In hierarchical order, they are: the variable of static relative leg strength - endurance of the fingers (the angle of the lower leg and thigh 900 (SRL2 which arithmetic mean is 25.04 seconds and variable ctatic relative strength of arms and shoulders – push-up endurance in the balance beam (angle of the forearm and upper arm 900 ( SRA2 with arithmetic mean of 17.75 seconds. From the statistically influential significant predictor variables on the criterion variable one is from the static relative leg strength (SRL2 and the other is from the static relative strength of arm and shoulder area (SRA2. With the analysis of these relations we can conclude that the isometric contractions of the four headed thigh muscle and the isometric contractions of the three headed upper arm muscle are predominantly responsible for the successful execution of doing actions on a bicycle ergometer and not on the maximum relative receiving of oxygen.

Collective cell migration during inflammatory response

Science.gov (United States)

Wu, Di; Stroka, Kimberly; Aranda-Espinoza, Helim

2012-02-01

Wound scratch healing assays of endothelial cell monolayers is a simple model to study collective cell migration as a function of biological signals. A signal of particular interest is the immune response, which after initial wounding in vivo causes the release of various inflammatory factors such as tumor necrosis alpha (TNF-α). TNF-α is an innate inflammatory cytokine that can induce cell growth, cell necrosis, and change cell morphology. We studied the effects of TNF-α on collective cell migration using the wound healing assays and measured several migration metrics, such as rate of scratch closure, velocities of leading edge and bulk cells, closure index, and velocity correlation functions between migrating cells. We observed that TNF-α alters all migratory metrics as a function of the size of the scratch and TNF-α content. The changes observed in migration correlate with actin reorganization upon TNF-α exposure.

An investigation of the static and dynamic behavior of electrically actuated rectangular microplates

KAUST Repository

Saghir, S.

2016-06-16

We present an investigation of the static and dynamic behavior of the nonlinear von-Karman plates when actuated by the nonlinear electrostatic forces. The investigation is based on a reduced order model developed using the Galerkin method, which rely on modeshapes and in-plane shape functions extracted using a finite element method. In this study, a fully clamped microplate is considered. We investigate the static behavior and the effect of different non-dimensional design parameters. The static results are validated by comparison with the results calculated by a finite element model. The forced-vibration response of the plate is then investigated when the plate is excited by a harmonic AC load superimposed to a DC load. The dynamic behavior is examined near the primary and secondary (superharmonic and subharmonic) resonances. The microplate shows a strong hardening behavior due to the cubic nonlinearity of mid-plane stretching. However, the behavior switches to softening as the DC load is increased. Finally, near-square plates are studied to understand the effect of geometric imperfections of microplates.

An investigation of the static and dynamic behavior of electrically actuated rectangular microplates

KAUST Repository

Saghir, Shahid; Younis, Mohammad I.

2016-01-01

We present an investigation of the static and dynamic behavior of the nonlinear von-Karman plates when actuated by the nonlinear electrostatic forces. The investigation is based on a reduced order model developed using the Galerkin method, which rely on modeshapes and in-plane shape functions extracted using a finite element method. In this study, a fully clamped microplate is considered. We investigate the static behavior and the effect of different non-dimensional design parameters. The static results are validated by comparison with the results calculated by a finite element model. The forced-vibration response of the plate is then investigated when the plate is excited by a harmonic AC load superimposed to a DC load. The dynamic behavior is examined near the primary and secondary (superharmonic and subharmonic) resonances. The microplate shows a strong hardening behavior due to the cubic nonlinearity of mid-plane stretching. However, the behavior switches to softening as the DC load is increased. Finally, near-square plates are studied to understand the effect of geometric imperfections of microplates.

Intestinal Epithelial Cells Modulate Antigen-Presenting Cell Responses to Bacterial DNA

Science.gov (United States)

Campeau, J. L.; Salim, S. Y.; Albert, E. J.; Hotte, N.

2012-01-01

Intestinal epithelial cells and antigen-presenting cells orchestrate mucosal innate immunity. This study investigated the role of bacterial DNA in modulating epithelial and bone marrow-derived antigen-presenting cells (BM-APCs) and subsequent T-lymphocyte responses. Murine MODE-K epithelial cells and BM-APCs were treated with DNA from either Bifidobacterium breve or Salmonella enterica serovar Dublin directly and under coculture conditions with CD4+ T cells. Apical stimulation of MODE-K cells with S. Dublin DNA enhanced secretion of cytokines from underlying BM-APCs and induced interleukin-17 (IL-17) and gamma interferon (IFN-γ) secretion from CD4+ T cells. Bacterial DNA isolated from either strain induced maturation and increased cytokine secretion from BM-APCs. Conditioned medium from S. Dublin-treated MODE-K cells elicited an increase in cytokine secretion similar to that seen for S. Dublin DNA. Treatment of conditioned medium from MODE-K cells with RNase and protease prevented the S. Dublin-induced increased cytokine secretion. Oral feeding of mice with B. breve DNA resulted in enhanced levels of colonic IL-10 and transforming growth factor β (TGFβ) compared with what was seen for mice treated with S. Dublin DNA. In contrast, feeding mice with S. Dublin DNA increased levels of colonic IL-17 and IL-12p70. T cells from S. Dublin DNA-treated mice secreted high levels of IL-12 and IFN-γ compared to controls and B. breve DNA-treated mice. These results demonstrate that intestinal epithelial cells are able to modulate subsequent antigen-presenting and T-cell responses to bacterial DNA with pathogenic but not commensal bacterial DNA inducing effector CD4+ T lymphocytes. PMID:22615241

Enthesis fibrocartilage cells originate from a population of Hedgehog-responsive cells modulated by the loading environment.

Science.gov (United States)

Schwartz, Andrea G; Long, Fanxin; Thomopoulos, Stavros

2015-01-01

Tendon attaches to bone across a specialized tissue called the enthesis. This tissue modulates the transfer of muscle forces between two materials, i.e. tendon and bone, with vastly different mechanical properties. The enthesis for many tendons consists of a mineralized graded fibrocartilage that develops postnatally, concurrent with epiphyseal mineralization. Although it is well described that the mineralization and development of functional maturity requires muscle loading, the biological factors that modulate enthesis development are poorly understood. By genetically demarcating cells expressing Gli1 in response to Hedgehog (Hh) signaling, we discovered a unique population of Hh-responsive cells in the developing murine enthesis that were distinct from tendon fibroblasts and epiphyseal chondrocytes. Lineage-tracing experiments revealed that the Gli1 lineage cells that originate in utero eventually populate the entire mature enthesis. Muscle paralysis increased the number of Hh-responsive cells in the enthesis, demonstrating that responsiveness to Hh is modulated in part by muscle loading. Ablation of the Hh-responsive cells during the first week of postnatal development resulted in a loss of mineralized fibrocartilage, with very little tissue remodeling 5 weeks after cell ablation. Conditional deletion of smoothened, a molecule necessary for responsiveness to Ihh, from the developing tendon and enthesis altered the differentiation of enthesis progenitor cells, resulting in significantly reduced fibrocartilage mineralization and decreased biomechanical function. Taken together, these results demonstrate that Hh signaling within developing enthesis fibrocartilage cells is required for enthesis formation. © 2015. Published by The Company of Biologists Ltd.

An Arabidopsis kinase cascade influences auxin-responsive cell expansion.

Science.gov (United States)

Enders, Tara A; Frick, Elizabeth M; Strader, Lucia C

2017-10-01

Mitogen-activated protein kinase (MPK) cascades are conserved mechanisms of signal transduction across eukaryotes. Despite the importance of MPK proteins in signaling events, specific roles for many Arabidopsis MPK proteins remain unknown. Multiple studies have suggested roles for MPK signaling in a variety of auxin-related processes. To identify MPK proteins with roles in auxin response, we screened mpk insertional alleles and identified mpk1-1 as a mutant that displays hypersensitivity in auxin-responsive cell expansion assays. Further, mutants defective in the upstream MAP kinase kinase MKK3 also display hypersensitivity in auxin-responsive cell expansion assays, suggesting that this MPK cascade affects auxin-influenced cell expansion. We found that MPK1 interacts with and phosphorylates ROP BINDING PROTEIN KINASE 1 (RBK1), a protein kinase that interacts with members of the Rho-like GTPases from Plants (ROP) small GTPase family. Similar to mpk1-1 and mkk3-1 mutants, rbk1 insertional mutants display auxin hypersensitivity, consistent with a possible role for RBK1 downstream of MPK1 in influencing auxin-responsive cell expansion. We found that RBK1 directly phosphorylates ROP4 and ROP6, supporting the possibility that RBK1 effects on auxin-responsive cell expansion are mediated through phosphorylation-dependent modulation of ROP activity. Our data suggest a MKK3 • MPK1 • RBK1 phosphorylation cascade that may provide a dynamic module for altering cell expansion. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Th17 cell-mediated immune responses promote mast cell proliferation by triggering stem cell factor in keratinocytes

International Nuclear Information System (INIS)

Cho, Kyung-Ah; Park, Minhwa; Kim, Yu-Hee; Woo, So-Youn

2017-01-01

Although mast cells are traditionally thought to function as effector cells in allergic responses, they have increasingly been recognized as important regulators of various immune responses. Mast cells mature locally; thus, tissue-specific influences are important for promoting mast cell accumulation and survival in the skin and the gastrointestinal tract. In this study, we determined the effects of keratinocytes on mast cell accumulation during Th17-mediated skin inflammation. We observed increases in dermal mast cells in imiquimod-induced psoriatic dermatitis in mice accompanied by the expression of epidermal stem cell factor (SCF), a critical mast cell growth factor. Similar to mouse epidermal keratinocytes, SCF was highly expressed in the human HaCaT keratinocyte cell line following stimulation with IL−17. Further, keratinocytes promoted mast cell proliferation following stimulation with IL−17 in vitro. However, the effects of keratinocytes on mast cells were significantly diminished in the presence of anti−CD117 (stem cell factor receptor) blocking antibodies. Taken together, our results revealed that the Th17-mediated inflammatory environment promotes mast cell accumulation through keratinocyte-derived SCF. - Highlights: • Psoriasis-like skin inflammation increase dermal mast cells. • Keratinocyte produce stem cell factor in psoriasis-like skin inflammation. • Keratinocyte promote mast cell proliferation by stem cell factor dependent manner

Quasi-Static Condensation of Aeroelastic Suspension Bridge Model

DEFF Research Database (Denmark)

Møller, Randi N.; Krenk, Steen; N. Svendsen, Martin

2017-01-01

For long span bridges the wind-induced dynamic response is a design driving factor and therefore continuously a subject for detailed analysis. Traditionally both buffeting and stability calculations have been considered in the frequency domain. However, this yields alimitation in accounting...... for turbulence when considering the stability limit and further it is not possible to account for non-linear effects. These limitations suggest to do simulations of the aeroelastic response of long span bridges in the time domain. For this it is of interest to have an efficient model while still maintaining...... sufficient accuracy. This contribution is on quasi-static reduction of an aeroelastic finite element model of a 3000m suspension bridge proposed for crossing Sulafjorden in Norway. The model is intended for stability limit calculation where the representation of higher modes is of less importance...

Human dental pulp cells exhibit bone cell-like responsiveness to fluid shear stress.

Science.gov (United States)

Kraft, David Christian Evar; Bindslev, Dorth Arenholt; Melsen, Birte; Klein-Nulend, Jenneke

2011-02-01

For engineering bone tissue to restore, for example, maxillofacial defects, mechanosensitive cells are needed that are able to conduct bone cell-specific functions, such as bone remodelling. Mechanical loading affects local bone mass and architecture in vivo by initiating a cellular response via loading-induced flow of interstitial fluid. After surgical removal of ectopically impacted third molars, human dental pulp tissue is an easily accessible and interesting source of cells for mineralized tissue engineering. The aim of this study was to determine whether human dental pulp-derived cells (DPC) are responsive to mechanical loading by pulsating fluid flow (PFF) upon stimulation of mineralization in vitro. Human DPC were incubated with or without mineralization medium containing differentiation factors for 3 weeks. Cells were subjected to 1-h PFF (0.7 ± 0.3 Pa, 5 Hz) and the response was quantified by measuring nitric oxide (NO) and prostaglandin E₂ (PGE₂) production, and gene expression of cyclooxygenase (COX)-1 and COX-2. We found that DPC are intrinsically mechanosensitive and, like osteogenic cells, respond to PFF-induced fluid shear stress. PFF stimulated NO and PGE₂ production, and up-regulated COX-2 but not COX-1 gene expression. In DPC cultured under mineralizing conditions, the PFF-induced NO, but not PGE₂, production was significantly enhanced. These data suggest that human DPC, like osteogenic cells, acquire responsiveness to pulsating fluid shear stress in mineralizing conditions. Thus DPC might be able to perform bone-like functions during mineralized tissue remodeling in vivo, and therefore provide a promising new tool for mineralized tissue engineering to restore, for example, maxillofacial defects.

Counterterms for static Lovelock solutions

International Nuclear Information System (INIS)

Mehdizadeh, M.R.; Dehghani, M.H.; Zangeneh, M.K.

2015-01-01

In this paper, we introduce the counterterms that remove the non-logarithmic divergences of the action in third order Lovelock gravity for static spacetimes. We do this by defining the cosmological constant in such a way that the asymptotic form of the metric have the same form in Lovelock and Einstein gravities. Thus, we employ the counterterms of Einstein gravity and show that the power law divergences of the action of Lovelock gravity for static spacetimes can be removed by suitable choice of coefficients. We find that the dependence of these coefficients on the dimension in Lovelock gravity is the same as in Einstein gravity. We also introduce the finite energy-momentum tensor and employ these counterterms to calculate the finite action and mass of static black hole solutions of third order Lovelock gravity. Next, we calculate the thermodynamic quantities and show that the entropy calculated through the use of Gibbs-Duhem relation is consistent with the obtained entropy by Wald's formula. Furthermore, we find that in contrast to Einstein gravity in which there exists no uncharged extreme black hole, third order Lovelock gravity can have these kind of black holes. Finally, we investigate the stability of static charged black holes of Lovelock gravity in canonical ensemble and find that small black holes show a phase transition between very small and small black holes, while the large ones are stable. (orig.)

Counterterms for static Lovelock solutions

Energy Technology Data Exchange (ETDEWEB)

Mehdizadeh, M.R. [Shahid Bahonar University, Department of Physics, PO Box 76175, Kerman (Iran, Islamic Republic of); Dehghani, M.H. [Research Institute for Astrophysics and Astronomy of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Zangeneh, M.K. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)

2015-06-15

In this paper, we introduce the counterterms that remove the non-logarithmic divergences of the action in third order Lovelock gravity for static spacetimes. We do this by defining the cosmological constant in such a way that the asymptotic form of the metric have the same form in Lovelock and Einstein gravities. Thus, we employ the counterterms of Einstein gravity and show that the power law divergences of the action of Lovelock gravity for static spacetimes can be removed by suitable choice of coefficients. We find that the dependence of these coefficients on the dimension in Lovelock gravity is the same as in Einstein gravity. We also introduce the finite energy-momentum tensor and employ these counterterms to calculate the finite action and mass of static black hole solutions of third order Lovelock gravity. Next, we calculate the thermodynamic quantities and show that the entropy calculated through the use of Gibbs-Duhem relation is consistent with the obtained entropy by Wald's formula. Furthermore, we find that in contrast to Einstein gravity in which there exists no uncharged extreme black hole, third order Lovelock gravity can have these kind of black holes. Finally, we investigate the stability of static charged black holes of Lovelock gravity in canonical ensemble and find that small black holes show a phase transition between very small and small black holes, while the large ones are stable. (orig.)

PKC activation induces inflammatory response and cell death in human bronchial epithelial cells.

Directory of Open Access Journals (Sweden)

Hyunhee Kim

Full Text Available A variety of airborne pathogens can induce inflammatory responses in airway epithelial cells, which is a crucial component of host defence. However, excessive inflammatory responses and chronic inflammation also contribute to different diseases of the respiratory system. We hypothesized that the activation of protein kinase C (PKC is one of the essential mechanisms of inflammatory response in airway epithelial cells. In the present study, we stimulated human bronchial lung epithelial (BEAS-2B cells with the phorbol ester Phorbol 12, 13-dibutyrate (PDBu, and examined gene expression profile using microarrays. Microarray analysis suggests that PKC activation induced dramatic changes in gene expression related to multiple cellular functions. The top two interaction networks generated from these changes were centered on NFκB and TNF-α, which are two commonly known pathways for cell death and inflammation. Subsequent tests confirmed the decrease in cell viability and an increase in the production of various cytokines. Interestingly, each of the increased cytokines was differentially regulated at mRNA and/or protein levels by different sub-classes of PKC isozymes. We conclude that pathological cell death and cytokine production in airway epithelial cells in various situations may be mediated through PKC related signaling pathways. These findings suggest that PKCs can be new targets for treatment of lung diseases.

Common Features of Regulatory T Cell Specialization During Th1 Responses

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Katharina Littringer

2018-06-01

Full Text Available CD4+Foxp3+ Treg cells are essential for maintaining self-tolerance and preventing excessive immune responses. In the context of Th1 immune responses, co-expression of the Th1 transcription factor T-bet with Foxp3 is essential for Treg cells to control Th1 responses. T-bet-dependent expression of CXCR3 directs Treg cells to the site of inflammation. However, the suppressive mediators enabling effective control of Th1 responses at this site are unknown. In this study, we determined the signature of CXCR3+ Treg cells arising in Th1 settings and defined universal features of Treg cells in this context using multiple Th1-dominated infection models. Our analysis defined a set of Th1-specific co-inhibitory receptors and cytotoxic molecules that are specifically expressed in Treg cells during Th1 immune responses in mice and humans. Among these, we identified the novel co-inhibitory receptor CD85k as a functional predictor for Treg-mediated suppression specifically of Th1 responses, which could be explored therapeutically for selective immune suppression in autoimmunity.

Static analysis of a Model of the LDL degradation pathway

DEFF Research Database (Denmark)

Pilegaard, Henrik; Nielson, Flemming; Nielson, Hanne Riis

2005-01-01

BioAmbients is a derivative of mobile ambients that has shown promise of describing interesting features of the behaviour of biological systems. As for other ambient calculi static program analysis can be used to compute safe approximations of the behavior of modelled systems. We use these tools ...... to model and analyse the production of cholesterol in living cells and show that we are able to pinpoint the difference in behaviour between models of healthy systems and models of mutated systems giving rise to known diseases....

T-helper cell-mediated proliferation and cytokine responses against recombinant Merkel cell polyomavirus-like particles.

Directory of Open Access Journals (Sweden)

Arun Kumar

Full Text Available The newly discovered Merkel Cell Polyomavirus (MCPyV resides in approximately 80% of Merkel cell carcinomas (MCC. Causal role of MCPyV for this rare and aggressive skin cancer is suggested by monoclonal integration and truncation of large T (LT viral antigen in MCC cells. The mutated MCPyV has recently been found in highly purified leukemic cells from patients with chronic lymphocytic leukemia (CLL, suggesting a pathogenic role also in CLL. About 50-80% of adults display MCPyV-specific antibodies. The humoral immunity does not protect against the development of MCC, as neutralizing MCPyV antibodies occur in higher levels among MCC patients than healthy controls. Impaired T-cell immunity has been linked with aggressive MCC behavior. Therefore, cellular immunity appears to be important in MCPyV infection surveillance. In order to elucidate the role of MCPyV-specific Th-cell immunity, peripheral blood mononuclear cells (PBMC of healthy adults were stimulated with MCPyV VP1 virus-like particles (VLPs, using human bocavirus (HBoV VLPs and Candida albicans antigen as positive controls. Proliferation, IFN-γ, IL-13 and IL-10 responses were examined in 15 MCPyV-seropositive and 15 seronegative volunteers. With the MCPyV antigen, significantly stronger Th-cell responses were found in MCPyV-seropositive than MCPyV-seronegative subjects, whereas with the control antigens, the responses were statistically similar. The most readily detectable cytokine was IFN-γ. The MCPyV antigen tended to induce stronger IFN-γ responses than HBoV VLP antigen. Taken together, MCPyV-specific Th-cells elicit vigorous IFN-γ responses. IFN-γ being a cytokine with major antiviral and tumor suppressing functions, Th-cells are suggested to be important mediators of MCPyV-specific immune surveillance.

Comparison of stochastic resonance in static and dynamical nonlinearities

International Nuclear Information System (INIS)

Ma, Yumei; Duan, Fabing

2014-01-01

We compare the stochastic resonance (SR) effects in parallel arrays of static and dynamical nonlinearities via the measure of output signal-to-noise ratio (SNR). For a received noisy periodic signal, parallel arrays of both static and dynamical nonlinearities can enhance the output SNR by optimizing the internal noise level. The static nonlinearity is easily implementable, while the dynamical nonlinearity has more parameters to be tuned, at the risk of not exploiting the beneficial role of internal noise components. It is of interest to note that, for an input signal buried in the external Laplacian noise, we show that the dynamical nonlinearity is superior to the static nonlinearity in obtaining a better output SNR. This characteristic is assumed to be closely associated with the kurtosis of noise distribution. - Highlights: • Comparison of SR effects in arrays of both static and dynamical nonlinearities. • Static nonlinearity is easily implementable for the SNR enhancement. • Dynamical nonlinearity yields a better output SNR for external Laplacian noise

NaCl responsive taste cells in the mouse fungiform taste buds.

Science.gov (United States)

Yoshida, R; Horio, N; Murata, Y; Yasumatsu, K; Shigemura, N; Ninomiya, Y

2009-03-17

Previous studies have demonstrated that rodents' chorda tympani (CT) nerve fibers responding to NaCl can be classified according to their sensitivities to the epithelial sodium channel (ENaC) blocker amiloride into two groups: amiloride-sensitive (AS) and -insensitive (AI). The AS fibers were shown to respond specifically to NaCl, whereas AI fibers broadly respond to various electrolytes, including NaCl. These data suggest that salt taste transduction in taste cells may be composed of at least two different systems; AS and AI ones. To further address this issue, we investigated the responses to NaCl, KCl and HCl and the amiloride sensitivity of mouse fungiform papilla taste bud cells which are innervated by the CT nerve. Comparable with the CT data, the results indicated that 56 NaCl-responsive cells tested were classified into two groups; 25 cells ( approximately 44%) narrowly responded to NaCl and their NaCl response were inhibited by amiloride (AS cells), whereas the remaining 31 cells ( approximately 56%) responded not only to NaCl, but to KCl and/or HCl and showed no amiloride inhibition of NaCl responses (AI cells). Amiloride applied to the basolateral side of taste cells had no effect on NaCl responses in the AS and AI cells. Single cell reverse transcription-polymerase chain reaction (RT-PCR) experiments indicated that ENaC subunit mRNA was expressed in a subset of AS cells. These findings suggest that the mouse fungiform taste bud is composed of AS and AI cells that can transmit taste information differently to their corresponding types of CT fibers, and apical ENaCs may be involved in the NaCl responses of AS cells.

Elucidating the Function of Penetratin and a Static Magnetic Field in Cellular Uptake of Magnetic Nanoparticles

Directory of Open Access Journals (Sweden)

David Stirling

2013-02-01

Full Text Available Nanotechnology plays an increasingly important role in the biomedical arena. In particular, magnetic nanoparticles (mNPs have become important tools in molecular diagnostics, in vivo imaging and improved treatment of disease, with the ultimate aim of producing a more theranostic approach. Due to their small sizes, the nanoparticles can cross most of the biological barriers such as the blood vessels and the blood brain barrier, thus providing ubiquitous access to most tissues. In all biomedical applications maximum nanoparticle uptake into cells is required. Two promising methods employed to this end include functionalization of mNPs with cell-penetrating peptides to promote efficient translocation of cargo into the cell and the use of external magnetic fields for enhanced delivery. This study aimed to compare the effect of both penetratin and a static magnetic field with regards to the cellular uptake of 200 nm magnetic NPs and determine the route of uptake by both methods. Results demonstrated that both techniques increased particle uptake, with penetratin proving more cell specific. Clathrin- medicated endocytosis appeared to be responsible for uptake as shown via PCR and western blot, with Pitstop 2 (known to selectively block clathrin formation blocking particle uptake. Interestingly, it was further shown that a magnetic field was able to reverse or overcome the blocking, suggesting an alternative route of uptake.

A virtual clinical trial comparing static versus dynamic PET imaging in measuring response to breast cancer therapy

Science.gov (United States)

Wangerin, Kristen A.; Muzi, Mark; Peterson, Lanell M.; Linden, Hannah M.; Novakova, Alena; Mankoff, David A.; E Kinahan, Paul

2017-05-01

We developed a method to evaluate variations in the PET imaging process in order to characterize the relative ability of static and dynamic metrics to measure breast cancer response to therapy in a clinical trial setting. We performed a virtual clinical trial by generating 540 independent and identically distributed PET imaging study realizations for each of 22 original dynamic fluorodeoxyglucose (18F-FDG) breast cancer patient studies pre- and post-therapy. Each noise realization accounted for known sources of uncertainty in the imaging process, such as biological variability and SUV uptake time. Four definitions of SUV were analyzed, which were SUVmax, SUVmean, SUVpeak, and SUV50%. We performed a ROC analysis on the resulting SUV and kinetic parameter uncertainty distributions to assess the impact of the variability on the measurement capabilities of each metric. The kinetic macro parameter, K i , showed more variability than SUV (mean CV K i   =  17%, SUV  =  13%), but K i pre- and post-therapy distributions also showed increased separation compared to the SUV pre- and post-therapy distributions (mean normalized difference K i   =  0.54, SUV  =  0.27). For the patients who did not show perfect separation between the pre- and post-therapy parameter uncertainty distributions (ROC AUC  dynamic imaging outperformed SUV in distinguishing metabolic change in response to therapy, ranging from 12 to 14 of 16 patients over all SUV definitions and uptake time scenarios (p  PET imaging.

Static Transition Compression

DEFF Research Database (Denmark)

Danvy, Olivier; Damian, Daniel

2001-01-01

Starting from an operational specification of a translation from a structured to an unstructured imperative language, we point out how a compositional and context-insensitive translation gives rise to static chains of jumps. Taking an inspiration from the notion of continuation, we state a new co...

The supply voltage scaled dependency of the recovery of single event upset in advanced complementary metal—oxide—semiconductor static random-access memory cells

International Nuclear Information System (INIS)

Li Da-Wei; Qin Jun-Rui; Chen Shu-Ming

2013-01-01

Using computer-aided design three-dimensional simulation technology, the supply voltage scaled dependency of the recovery of single event upset and charge collection in static random-access memory cells are investigated. It reveals that the recovery linear energy transfer threshold decreases with the supply voltage reducing, which is quite attractive for dynamic voltage scaling and subthreshold circuit radiation-hardened design. Additionally, the effect of supply voltage on charge collection is also investigated. It is concluded that the supply voltage mainly affects the bipolar gain of the parasitical bipolar junction transistor (BJT) and the existence of the source plays an important role in supply voltage variation. (geophysics, astronomy, and astrophysics)

T-cell responses targeting HIV Nef uniquely correlate with infected cell frequencies after long-term antiretroviral therapy.

Directory of Open Access Journals (Sweden)

Allison S Thomas

2017-09-01

Full Text Available HIV-specific CD8+ T-cell responses limit viral replication in untreated infection. After the initiation of antiretroviral therapy (ART, these responses decay and the infected cell population that remains is commonly considered to be invisible to T-cells. We hypothesized that HIV antigen recognition may persist in ART-treated individuals due to low-level or episodic protein expression. We posited that if persistent recognition were occurring it would be preferentially directed against the early HIV gene products Nef, Tat, and Rev as compared to late gene products, such as Gag, Pol, and Env, which have higher barriers to expression. Using a primary cell model of latency, we observed that a Nef-specific CD8+ T-cell clone exhibited low-level recognition of infected cells prior to reactivation and robust recognition shortly thereafter. A Gag-specific CD8+ T-cell clone failed to recognized infected cells under these conditions, corresponding with a lack of detectable Gag expression. We measured HIV-specific T-cell responses in 96 individuals who had been suppressed on ART for a median of 7 years, and observed a significant, direct correlation between cell-associated HIV DNA levels and magnitudes of IFN-γ-producing Nef/Tat/Rev-specific T-cell responses. This correlation was confirmed in an independent cohort (n = 18. Correlations were not detected between measures of HIV persistence and T-cell responses to other HIV antigens. The correlation with Nef/Tat/Rev-specific T-cells was attributable to Nef-specific responses, the breadth of which also correlated with HIV DNA levels. These results suggest that ongoing Nef expression in ART-treated individuals drives preferential maintenance and/or expansion of T-cells reactive to this protein, implying sensing of infected cells by the immune system. The direct correlation, however, suggests that recognition does not result in efficient elimination of infected cells. These results raise the possibility that

Cell Culture in Microgravity: Opening the Door to Space Cell Biology

Science.gov (United States)

Pellis, Neal R.; Dawson, David L. (Technical Monitor)

1999-01-01

Adaptational response of human cell populations to microgravity is investigated using simulation, short-term Shuttle experiments, and long-term microgravity. Simulation consists of a clinostatically-rotated cell culture system. The system is a horizontally-rotated cylinder completely filled with culture medium. Low speed rotation results in continuous-fall of the cells through the fluid medium. In this setting, cells: 1) aggregate, 2) propagate in three dimensions, 3) synthesize matrix, 4) differentiate, and 5) form sinusoids that facilitate mass transfer. Space cell culture is conducted in flight bioreactors and in static incubators. Cells grown in microgravity are: bovine cartilage, promyelocytic leukemia, kidney proximal tubule cells, adrenal medulla, breast and colon cancer, and endothelium. Cells were cultured in space to test specific hypotheses. Cartilage cells were used to determine structural differences in cartilage grown in space compared to ground-based bioreactors. Results from a 130-day experiment on Mir revealed that cartilage grown in space was substantially more compressible due to insufficient glycosaminoglycan in the matrix. Interestingly, earth-grown cartilage conformed better to the dimensions of the scaffolding material, while the Mir specimens were spherical. The other cell populations are currently being analyzed for cell surface properties, gene expression, and differentiation. Results suggest that some cells spontaneously differentiate in microgravity. Additionally, vast changes in gene expression may occur in response to microgravity. In conclusion, the transition to microgravity may constitute a physical perturbation in cells resulting in unique gene expressions, the consequences of which may be useful in tissue engineering, disease modeling, and space cell biology.

14 CFR 25.173 - Static longitudinal stability.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 25.173... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stability § 25.173 Static... forces (including friction) must be as follows: (a) A pull must be required to obtain and maintain speeds...

Elevated-Temperature Tests Under Static and Aerodynamic Conditions on Honeycomb-Core Sandwich Panels

Science.gov (United States)

Groen, Joseph M.; Johnson, Aldie E., Jr.

1959-01-01

Stainless-steel honeycomb-core sandwich panels which differed primarily in skin thicknesses were tested at elevated temperatures under static and aerodynamic conditions. The results of these tests were evaluated to determine the insulating effectiveness and structural integrity of the panels. The static radiant-heating tests were performed in front of a quartz-tube radiant heater at panel skin temperatures up to 1,5000 F. The aerodynamic tests were made in a Mach 1.4 heated blowdown wind tunnel. The tunnel temperature was augmented by additional heat supplied by a radiant heater which raised the panel surface temperature above 8000 F during air flow. Static radiant-heating tests of 2 minutes duration showed that all the panels protected the load-carrying structure about equally well. Thin-skin panels showed an advantage for this short-time test over thick-skin panels from a standpoint of weight against insulation. Permanent inelastic strains in the form of local buckles over each cell of the honeycomb core caused an increase in surface roughness. During the aero- dynamic tests all of the panels survived with little or no damage, and panel flutter did not occur.

A dynamic real time in vivo and static ex vivo analysis of granulomonocytic cell migration in the collagen-induced arthritis model.

Directory of Open Access Journals (Sweden)

Ruth Byrne

Full Text Available Neutrophilic granulocytes and monocytes (granulomonocytic cells; GMC drive the inflammatory process at the earliest stages of rheumatoid arthritis (RA. The migratory behavior and functional properties of GMC within the synovial tissue are, however, only incompletely characterized. Here we have analyzed GMC in the murine collagen-induced arthritis (CIA model of RA using multi-photon real time in vivo microscopy together with ex vivo analysis of GMC in tissue sections.GMC were abundant as soon as clinical arthritis was apparent. GMC were motile and migrated randomly through the synovial tissue. In addition, we observed the frequent formation of cell clusters consisting of both neutrophilic granulocytes and monocytes that actively contributed to the inflammatory process of arthritis. Treatment of animals with a single dose of prednisolone reduced the mean velocity of cell migration and diminished the overall immigration of GMC.In summary, our study shows that the combined application of real time in vivo microscopy together with elaborate static post-mortem analysis of GMC enables the description of dynamic migratory characteristics of GMC together with their precise location in a complex anatomical environment. Moreover, this approach is sensitive enough to detect subtle therapeutic effects within a very short period of time.

Responses of fibroblasts and glial cells to nanostructured platinum surfaces

Energy Technology Data Exchange (ETDEWEB)

Pennisi, C P; Sevcencu, C; Yoshida, K [Center for Sensory-Motor Interaction (SMI), Aalborg University, Aalborg (Denmark); Dolatshahi-Pirouz, A; Foss, M; Larsen, A Nylandsted; Besenbacher, F [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus (Denmark); Hansen, J Lundsgaard [Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark); Zachar, V, E-mail: cpennisi@hst.aau.d [Laboratory for Stem Cell Research, Aalborg University (Denmark)

2009-09-23

The chronic performance of implantable neural prostheses is affected by the growth of encapsulation tissue onto the stimulation electrodes. Encapsulation is associated with activation of connective tissue cells at the electrode's metallic contacts, usually made of platinum. Since surface nanotopography can modulate the cellular responses to materials, the aim of the present work was to evaluate the 'in vitro' responses of connective tissue cells to platinum strictly by modulating its surface nanoroughness. Using molecular beam epitaxy combined with sputtering, we produced platinum nanostructured substrates consisting of irregularly distributed nanopyramids and investigated their effect on the proliferation, cytoskeletal organization and cellular morphology of primary fibroblasts and transformed glial cells. Cells were cultured on these substrates and their responses to surface roughness were studied. After one day in culture, the fibroblasts were more elongated and their cytoskeleton less mature when cultured on rough substrates. This effect increased as the roughness of the surface increased and was associated with reduced cell proliferation throughout the observation period (4 days). Morphological changes also occurred in glial cells, but they were triggered by a different roughness scale and did not affect cellular proliferation. In conclusion, surface nanotopography modulates the responses of fibroblasts and glial cells to platinum, which may be an important factor in optimizing the tissue response to implanted neural electrodes.

Visuo-spatial processing in a dynamic and a static working memory paradigm in schizophrenia

DEFF Research Database (Denmark)

Cocchi, Luca; Schenk, Françoise; Volken, Henri

2007-01-01

patients with schizophrenia and matched controls in a new working memory paradigm involving dynamic (the Ball Flight Task - BFT) or static (the Static Pattern Task - SPT) visual stimuli. In the BFT, the responses of the patients were apparently based on the retention of the last set of segments...... that visuo-spatial working memory can simply be dissociated into visual and spatial sub-components....... of the perceived trajectory, whereas control subjects relied on a more global strategy. We assume that the patients' performances are the result of a reduced capacity in chunking visual information since they relied mainly on the retention of the last set of segments. This assumption is confirmed by the poor...

Generalization of the memory integer model for the analysis of the quasi-static behaviour of polyurethane foams

International Nuclear Information System (INIS)

Jmal, Hamdi; Ju, Ming Lei; Dupuis, Raphael; Aubry, Evelyne

2014-01-01

Polyurethane foam is a cellular material characterized by an interesting mechanical spectrum of properties: low density, capacity to absorb the deformation energy and low stiffness. This spectrum of properties makes polyurethane foam commonly used in many thermal, acoustic and comfort applications. Several models, such as memory, hyper-elastic and pseudo-elastic models have been developed in the literature to describe the mechanical response of polyurethane foam under quasi-static and dynamic test conditions. The main disadvantage of these models is the dependence of their parameters against the test conditions (strain rate, maximum compression level, etc). This affects the general character of their representativeness to the quasi-static and dynamic behaviours of polyurethane foam. The main goal of this article is to implement reliable mechanical model which is able to provide the quasi-static response of the polyurethane foam under different strain rates and large compressive deformation. The dimensional parameters of our model can be expressed by the product of two independent parts; the first contain only the test conditions and the second define the dimensionless and invariant parameters that characterize the foam material. The developed model has been proposed after several experimental studies allowing the apprehension of the quasi-static behaviour (through unidirectional compression tests). The polyurethane foam, under large deformations, exhibits a nonlinear elastic behaviour and viscoelastic behaviour. To assess the ability of our model to be a general representation, three industrial polyurethane foams have been considered.

Biological response of cancer cells to radiation treatment

Directory of Open Access Journals (Sweden)

Rajamanickam eBaskar

2014-11-01

Full Text Available Cancer is a class of diseases characterized by uncontrolled cell growth and has the ability to spread or metastasize throughout the body. In recent years, remarkable progress has been made towards the understanding of proposed hallmarks of cancer development, care and treatment modalities. Radiation therapy or radiotherapy is an important and integral component of cancer management, mostly conferring a survival benefit. Radiation therapy destroys cancer by depositing high-energy radiation on the cancer tissues. Over the years, radiation therapy has been driven by constant technological advances and approximately 50% of all patients with localized malignant tumors are treated with radiation at some point in the course of their disease. In radiation oncology, research and development in the last three decades has led to considerable improvement in our understanding of the differential responses of normal and cancer cells. The biological effectiveness of radiation depends on the linear energy transfer (LET, total dose, number of fractions and radiosensitivity of the targeted cells or tissues. Radiation can either directly or indirectly (by producing free radicals damages the genome of the cell. This has been challenged in recent years by a newly identified phenomenon known as radiation induced bystander effect (RIBE. In RIBE, the non-irradiated cells adjacent to or located far from the irradiated cells/tissues demonstrate similar responses to that of the directly irradiated cells. Understanding the cancer cell responses during the fractions or after the course of irradiation will lead to improvements in therapeutic efficacy and potentially, benefitting a significant proportion of cancer patients. In this review, the clinical implications of radiation induced direct and bystander effects on the cancer cell are discussed.

Cell Wall Metabolism in Response to Abiotic Stress

Science.gov (United States)

Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

2015-01-01

This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

A static analysis method to determine the availability of kinetic energy from wind turbines

NARCIS (Netherlands)

Rawn, B.G.; Gibescu, M.; Kling, W.L.

2010-01-01

This paper introduces definitions and an analysis method for estimating how much kinetic energy can be made available for inertial response from a wind turbine over a year, and how much energy capture must be sacrificed to do so. The analysis is based on the static characteristics of wind turbines,

Antitumor Responses of Invariant Natural Killer T Cells

Directory of Open Access Journals (Sweden)

Jennie B. Altman

2015-01-01

Full Text Available Natural killer T (NKT cells are innate-like lymphocytes that were first described in the late 1980s. Since their initial description, numerous studies have collectively shed light on their development and effector function. These studies have highlighted the unique requirements for the activation of these lymphocytes and the functional responses that distinguish these cells from other effector lymphocyte populations such as conventional T cells and NK cells. This body of literature suggests that NKT cells play diverse nonredundant roles in a number of disease processes, including the initiation and propagation of airway hyperreactivity, protection against a variety of pathogens, development of autoimmunity, and mediation of allograft responses. In this review, however, we focus on the role of a specific lineage of NKT cells in antitumor immunity. Specifically, we describe the development of invariant NKT (iNKT cells and the factors that are critical for their acquisition of effector function. Next, we delineate the mechanisms by which iNKT cells influence and modulate the activity of other immune cells to directly or indirectly affect tumor growth. Finally, we review the successes and failures of clinical trials employing iNKT cell-based immunotherapies and explore the future prospects for the use of such strategies.

Suboptimal Criterion Learning in Static and Dynamic Environments.

Directory of Open Access Journals (Sweden)

Elyse H Norton

2017-01-01

Full Text Available Humans often make decisions based on uncertain sensory information. Signal detection theory (SDT describes detection and discrimination decisions as a comparison of stimulus "strength" to a fixed decision criterion. However, recent research suggests that current responses depend on the recent history of stimuli and previous responses, suggesting that the decision criterion is updated trial-by-trial. The mechanisms underpinning criterion setting remain unknown. Here, we examine how observers learn to set a decision criterion in an orientation-discrimination task under both static and dynamic conditions. To investigate mechanisms underlying trial-by-trial criterion placement, we introduce a novel task in which participants explicitly set the criterion, and compare it to a more traditional discrimination task, allowing us to model this explicit indication of criterion dynamics. In each task, stimuli were ellipses with principal orientations drawn from two categories: Gaussian distributions with different means and equal variance. In the covert-criterion task, observers categorized a displayed ellipse. In the overt-criterion task, observers adjusted the orientation of a line that served as the discrimination criterion for a subsequently presented ellipse. We compared performance to the ideal Bayesian learner and several suboptimal models that varied in both computational and memory demands. Under static and dynamic conditions, we found that, in both tasks, observers used suboptimal learning rules. In most conditions, a model in which the recent history of past samples determines a belief about category means fit the data best for most observers and on average. Our results reveal dynamic adjustment of discrimination criterion, even after prolonged training, and indicate how decision criteria are updated over time.

Results of comparative RBMK neutron computation using VNIIEF codes (cell computation, 3D statics, 3D kinetics). Final report

Energy Technology Data Exchange (ETDEWEB)

Grebennikov, A.N.; Zhitnik, A.K.; Zvenigorodskaya, O.A. [and others

1995-12-31

In conformity with the protocol of the Workshop under Contract {open_quotes}Assessment of RBMK reactor safety using modern Western Codes{close_quotes} VNIIEF performed a neutronics computation series to compare western and VNIIEF codes and assess whether VNIIEF codes are suitable for RBMK type reactor safety assessment computation. The work was carried out in close collaboration with M.I. Rozhdestvensky and L.M. Podlazov, NIKIET employees. The effort involved: (1) cell computations with the WIMS, EKRAN codes (improved modification of the LOMA code) and the S-90 code (VNIIEF Monte Carlo). Cell, polycell, burnup computation; (2) 3D computation of static states with the KORAT-3D and NEU codes and comparison with results of computation with the NESTLE code (USA). The computations were performed in the geometry and using the neutron constants presented by the American party; (3) 3D computation of neutron kinetics with the KORAT-3D and NEU codes. These computations were performed in two formulations, both being developed in collaboration with NIKIET. Formulation of the first problem maximally possibly agrees with one of NESTLE problems and imitates gas bubble travel through a core. The second problem is a model of the RBMK as a whole with imitation of control and protection system controls (CPS) movement in a core.

The Static Ladder Problem with Two Sources of Friction

Science.gov (United States)

Bennett, Jonathan; Mauney, Alex

2011-01-01

The problem of a ladder leaning against a wall in static equilibrium is a classic example encountered in introductory mechanics texts. Most discussions of this problem assume that the static frictional force between the ladder and wall can be ignored. A few authors consider the case where the static friction coefficients between ladder/wall…

The usefulness of cardiofocal collimator in static renal imaging

International Nuclear Information System (INIS)

Evren, I.; Durak, H.; Degirmenci, B.; Derebek, E.; Oezbilek, E.; Capa, G.

2001-01-01

Static renal imaging is best performed using pinhole collimator. But this technique takes too much time and generally parallel hole collimators are preferred for static renal imaging in nuclear medicine departments. The purpose of this study was to investigate the usefulness of the cardio-focal collimator used for myocardial perfusion imaging in static renal scintigraphy

Single Event Upset in Static Random Access Memories in Atmospheric Neutron Environments

Science.gov (United States)

Arita, Yutaka; Takai, Mikio; Ogawa, Izumi; Kishimoto, Tadafumi

2003-07-01

Single-event upsets (SEUs) in a 0.4 μm 4 Mbit complementary metal oxide semiconductor (CMOS) static random access memory (SRAM) were investigated in various atmospheric neutron environments at sea level, at an altitude of 2612 m mountain, at an altitude of commercial airplane, and at an underground depth of 476 m. Neutron-induced SEUs increase with the increase in altitude. For a device with a borophosphosilicate glass (BPSG) film, SEU rates induced by thermal neutrons increase with the decrease in the cell charge of a memory cell. A thermal neutron-induced SEU is significant in SRAMs with a small cell charge. With the conditions of small cell charge, thermal neutron-induced SEUs account for 60% or more of the total neutron-induced SEUs. The SEU rate induced by atmospheric thermal neutrons can be estimated by an acceleration test using 252Cf.

[Prediction of the molecular response to pertubations from single cell measurements].

Science.gov (United States)

Remacle, Françoise; Levine, Raphael D

2014-12-01

The response of protein signalization networks to perturbations is analysed from single cell measurements. This experimental approach allows characterizing the fluctuations in protein expression levels from cell to cell. The analysis is based on an information theoretic approach grounded in thermodynamics leading to a quantitative version of Le Chatelier principle which allows to predict the molecular response. Two systems are investigated: human macrophages subjected to lipopolysaccharide challenge, analogous to the immune response against Gram-negative bacteria and the response of the proteins involved in the mTOR signalizing network of GBM cancer cells to changes in partial oxygen pressure. © 2014 médecine/sciences – Inserm.

14 CFR 23.173 - Static longitudinal stability.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static longitudinal stability. 23.173... Stability § 23.173 Static longitudinal stability. Under the conditions specified in § 23.175 and with the airplane trimmed as indicated, the characteristics of the elevator control forces and the friction within...

14 CFR 25.1325 - Static pressure systems.

Science.gov (United States)

2010-01-01

... installation of the static pressure system must be such that— (1) Positive drainage of moisture is provided..., the other is blocked off; and (2) Both sources cannot be blocked off simultaneously. (h) For... other static pressure source being open or blocked. [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as...

Norovirus-specific memory T cell responses in adult human donors

Directory of Open Access Journals (Sweden)

Maria Malm

2016-10-01

Full Text Available Norovirus (NoV is a leading cause of acute gastroenteritis in people of all ages worldwide. NoV specific serum antibodies which block the binding of NoV virus-like particles (VLPs to the cell receptors have been thoroughly investigated. In contrast, only a few publications are available on the NoV capsid VP1 protein-specific T cell responses in humans naturally infected with the virus. Freshly isolated peripheral blood mononuclear cells of eight healthy adult human donors previously exposed to NoV were stimulated with purified VLPs derived from NoV GII.4-1999, GII.4-2012 (Sydney, and GI.3, and IFN-g production was measured by an ELISPOT assay. In addition, 76 overlapping synthetic peptides spanning the entire 539 amino acid sequence of GII.4 VP1 were pooled into two-dimensional matrices and used to identify putative T cell epitopes. Seven of the eight subjects produced IFN-g in response to the peptides and five subjects produced IFN-g in response to the VLPs of the same origin. In general, stronger T cell responses were induced with the peptides in each donor compared to the VLPs. A CD8+ T cell epitope in the shell domain of the VP1 (134SPSQVTMFPHIIVDVRQL151 was identified in two subjects, both having human leukocyte antigen (HLA-A*02:01 allele. To our knowledge, this is the first report using synthetic peptides to study NoV-specific T cell responses in human subjects and identify T cell epitopes.

Static potential for a string with a topological term

International Nuclear Information System (INIS)

Zaikov, R.P.; Zlatev, S.I.

1991-01-01

We study the static potential for a string in (2+1)-dimensional space-time with action including a topological term. An appropriate static solution is found and the corresponding potential is obtained. Such a solution does not exist beyond a critical distance between the ends of the string. The one-loop corrections to the static potential are calculated. (orig.)

Dynamic hubs show competitive and static hubs non-competitive regulation of their interaction partners.

Directory of Open Access Journals (Sweden)

Apurv Goel

Full Text Available Date hub proteins have 1 or 2 interaction interfaces but many interaction partners. This raises the question of whether all partner proteins compete for the interaction interface of the hub or if the cell carefully regulates aspects of this process? Here, we have used real-time rendering of protein interaction networks to analyse the interactions of all the 1 or 2 interface hubs of Saccharomyces cerevisiae during the cell cycle. By integrating previously determined structural and gene expression data, and visually hiding the nodes (proteins and their edges (interactions during their troughs of expression, we predict when interactions of hubs and their partners are likely to exist. This revealed that 20 out of all 36 one- or two- interface hubs in the yeast interactome fell within two main groups. The first was dynamic hubs with static partners, which can be considered as 'competitive hubs'. Their interaction partners will compete for the interaction interface of the hub and the success of any interaction will be dictated by the kinetics of interaction (abundance and affinity and subcellular localisation. The second was static hubs with dynamic partners, which we term 'non-competitive hubs'. Regulatory mechanisms are finely tuned to lessen the presence and/or effects of competition between the interaction partners of the hub. It is possible that these regulatory processes may also be used by the cell for the regulation of other, non-cell cycle processes.

B7h-expressing dendritic cells and plasma B cells mediate distinct outcomes of ICOS costimulation in T cell-dependent antibody responses

Directory of Open Access Journals (Sweden)

Larimore Kevin

2012-06-01

Full Text Available Abstract Background The ICOS-B7h costimulatory receptor-ligand pair is required for germinal center formation, the production of isotype-switched antibodies, and antibody affinity maturation in response to T cell-dependent antigens. However, the potentially distinct roles of regulated B7h expression on B cells and dendritic cells in T cell-dependent antibody responses have not been defined. Results We generated transgenic mice with lineage-restricted B7h expression to assess the cell-type specific roles of B7h expression on B cells and dendritic cells in regulating T cell-dependent antibody responses. Our results show that endogenous B7h expression is reduced on B cells after activation in vitro and is also reduced in vivo on antibody-secreting plasma B cells in comparison to both naïve and germinal center B cells from which they are derived. Increasing the level of B7h expression on activated and plasma B cells in B-B7hTg mice led to an increase in the number of antibody-secreting plasma cells generated after immunization and a corresponding increase in the concentration of antigen-specific high affinity serum IgG antibodies of all isotypes, without affecting the number of responding germinal center B cells. In contrast, ICOS costimulation mediated by dendritic cells in DC-B7hTg mice contributed to germinal center formation and selectively increased IgG2a production without affecting the overall magnitude of antibody responses. Conclusions Using transgenic mice with lineage-restricted B7h expression, we have revealed distinct roles of ICOS costimulation mediated by dendritic cells and B cells in the regulation of T cell-dependent antibody responses.

Secure communication of static information by electronic means

Science.gov (United States)

Gritton, Dale G.

1994-01-01

A method and apparatus (10) for the secure transmission of static data (16) from a tag (11) to a remote reader (12). Each time the static data (16) is to be transmitted to the reader (12), the 10 bits of static data (16) are combined with 54 bits of binary data (21), which constantly change from one transmission to the next, into a 64-bit number (22). This number is then encrypted and transmitted to the remote reader (12) where it is decrypted (26) to produce the same 64 bit number that was encrypted in the tag (11). With a continual change in the value of the 64 bit number (22) in the tag, the encrypted numbers transmitted to the reader (12) will appear to be dynamic in character rather than being static.

THE EXPERIENCE OF COMPARISON OF STATIC SECURITY CODE ANALYZERS

Directory of Open Access Journals (Sweden)

Alexey Markov

2015-09-01

Full Text Available This work presents a methodological approach to comparison of static security code analyzers. It substantiates the comparison of the static analyzers as to efficiency and functionality indicators, which are stipulated in the international regulatory documents. The test data for assessment of static analyzers efficiency is represented by synthetic sets of open-source software, which contain vulnerabilities. We substantiated certain criteria for quality assessment of the static security code analyzers subject to standards NIST SP 500-268 and SATEC. We carried out experiments that allowed us to assess a number of the Russian proprietary software tools and open-source tools. We came to the conclusion that it is of paramount importance to develop Russian regulatory framework for testing software security (firstly, for controlling undocumented features and evaluating the quality of static security code analyzers.

Optical measurements on hydrogen at ultrahigh static pressures. Summary report for NRIP W233

International Nuclear Information System (INIS)

Mills, R.L.; Liebenberg, D.H.

1979-02-01

The results of a two-year New Research Initiatives Program (NRIP) aimed at developing apparatus and techniques for studying hydrogen and other gases under ultrahigh static pressure in diamond--anvil cells are summarized. The following goals were achieved: A facility was established in which precision optical measurements can be made; special diamond cells for use at low temperatures were built; procedures were devised for loading cells with gases at high density; preliminary visual, x-ray, and spectral studies on various gases at pressures up to 50 kbar were conducted; and having demonstrated the feasibility of NRIP, other sponsorship on a continuing basis was obtained

Epithelium-innate immune cell axis in mucosal responses to SIV.

Science.gov (United States)

Shang, L; Duan, L; Perkey, K E; Wietgrefe, S; Zupancic, M; Smith, A J; Southern, P J; Johnson, R P; Haase, A T

2017-03-01

In the SIV (simian immunodeficiency virus)-rhesus macaque model of HIV-1 (human immunodeficiency virus type I) transmission to women, one hallmark of the mucosal response to exposure to high doses of SIV is CD4 T-cell recruitment that fuels local virus expansion in early infection. In this study, we systematically analyzed the cellular events and chemoattractant profiles in cervical tissues that precede CD4 T-cell recruitment. We show that vaginal exposure to the SIV inoculum rapidly induces chemokine expression in cervical epithelium including CCL3, CCL20, and CXCL8. The chemokine expression is associated with early recruitment of macrophages and plasmacytoid dendritic cells that are co-clustered underneath the cervical epithelium. Production of chemokines CCL3 and CXCL8 by these cells in turn generates a chemokine gradient that is spatially correlated with the recruitment of CD4 T cells. We further show that the protection of SIVmac239Δnef vaccination against vaginal challenge is correlated with the absence of this epithelium-innate immune cell-CD4 T-cell axis response in the cervical mucosa. Our results reveal a critical role for cervical epithelium in initiating early mucosal responses to vaginal infection, highlight an important role for macrophages in target cell recruitment, and provide further evidence of a paradoxical dampening effect of a protective vaccine on these early mucosal responses.

Pancreatic Endoderm-Derived From Diabetic Patient-Specific Induced Pluripotent Stem Cell Generates Glucose-Responsive Insulin-Secreting Cells.

Science.gov (United States)

Rajaei, Bahareh; Shamsara, Mehdi; Amirabad, Leila Mohammadi; Massumi, Mohammad; Sanati, Mohammad Hossein

2017-10-01

Human-induced pluripotent stem cells (hiPSCs) can potentially serve as an invaluable source for cell replacement therapy and allow the creation of patient- and disease-specific stem cells without the controversial use of embryos and avoids any immunological incompatibility. The generation of insulin-producing pancreatic β-cells from pluripotent stem cells in vitro provides an unprecedented cell source for personal drug discovery and cell transplantation therapy in diabetes. A new five-step protocol was introduced in this study, effectively induced hiPSCs to differentiate into glucose-responsive insulin-producing cells. This process mimics in vivo pancreatic organogenesis by directing cells through stages resembling definitive endoderm, primitive gut-tube endoderm, posterior foregut, pancreatic endoderm, and endocrine precursor. Each stage of differentiation were characterized by stage-specific markers. The produced cells exhibited many properties of functional β-cells, including expression of critical β-cells transcription factors, the potency to secrete C-peptide in response to high levels of glucose and the presence of mature endocrine secretory granules. This high efficient differentiation protocol, established in this study, yielded 79.18% insulin-secreting cells which were responsive to glucose five times higher than the basal level. These hiPSCs-derived glucose-responsive insulin-secreting cells might provide a promising approach for the treatment of type I diabetes mellitus. J. Cell. Physiol. 232: 2616-2625, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Indian Hedgehog Suppresses a Stromal Cell-Driven Intestinal Immune Response.

Science.gov (United States)

Westendorp, B Florien; Büller, Nikè V J A; Karpus, Olga N; van Dop, Willemijn A; Koster, Jan; Versteeg, Rogier; Koelink, Pim J; Snel, Clinton Y; Meisner, Sander; Roelofs, Joris J T H; Uhmann, Anja; Ver Loren van Themaat, Emiel; Heijmans, Jarom; Hahn, Heidi; Muncan, Vanesa; Wildenberg, Manon E; van den Brink, Gijs R

2018-01-01

Upon intestinal epithelial damage a complex wound healing response is initiated to restore epithelial integrity and defend against pathogenic invasion. Epithelium-derived Indian Hedgehog (Ihh) functions as a critical sensor in this process. Signaling occurs in a paracrine manner because the receptor for Ihh is expressed only in the mesenchyme, but the exact Hedgehog target cell has remained elusive. The aim of this study was to elucidate further the nature of this target cell in the context of intestinal inflammation. Hedgehog activity was modulated genetically in both cell type-specific and body-wide models and the resulting animals were analyzed for gene expression profiles and sensitivity for dextran sodium sulfate (DSS) colitis. To characterize the Hedgehog target cell, Gli1-CreERT2-Rosa26-ZsGreen animals were generated, which express ZsGreen in all Hedgehog-responsive cells. These cells were characterized using flow cytometry and immunofluorescence. Loss of Indian Hedgehog from the intestinal epithelium resulted in a rapid increase in expression of inflammation-related genes, accompanied by increased influx of immune cells. Animals with epithelium-specific deletion of Ihh or lacking the Hedgehog receptor Smoothened from Hedgehog target cells were more sensitive to DSS colitis. In contrast, specific deletion of Smoothened in the myeloid compartment did not alter the response to DSS. This suggests that Hedgehog signaling does not repress intestinal immunity through an effect on myeloid cells. Indeed, we found that Hedgehog-responsive cells expressed gp38, smooth muscle actin, and desmin, indicating a fibroblastic nature. Ihh signaling inhibited expression of C-X-C motif chemokine ligand 12 (CXCL12) in fibroblasts in vitro and in vivo, thereby impairing the recruitment of immune cells. We show that epithelium-derived Indian Hedgehog signals exclusively to fibroblasts in the intestine. Loss of Ihh leads to a rapid immune response with up-regulation of fibroblast

Effects of static orientation upon human optokinetic afternystagmus

Science.gov (United States)

Wall, C. 3rd; Merfeld, D. M.; Zupan, L.

1999-01-01

"Normal" human subjects were placed in a series of 5 static orientations with respect to gravity and were asked to view an optokinetic display moving at a constant angular velocity. The axis of rotation coincided with the subject's rostro-caudal axis and produced horizontal optokinetic nystagmus and afternystagmus. Wall (1) previously reported that these optokinetic afternystagmus responses were not well characterized by parametric fits to slow component velocity. The response for nose-up, however, was larger than for nose-down. This suggested that the horizontal eye movements measured during optokinetic stimulation might include an induced linear VOR component as presented in the body of this paper. To investigate this hypothesis, another analysis of these data has been made using cumulative slow component eye position. Some subjects' responses had reversals in afternystagmus direction. These reversals were "filled in" by a zero slow component velocity. This method of analysis gives a much more consistent result across subjects and shows that, on average, responses from the nose-down horizontal (prone) orientation are greatly reduced (p the responses to post-rotatory nystagmus after earth horizontal axis rotation. Ten of 11 subjects had larger responses in their supine than their prone orientation. Application of horizontal axis optokinetic afternystagmus for clinical otolith function testing, and implications for altered gravity experiments are discussed.

Pre-exposure to moving form enhances static form sensitivity.

Directory of Open Access Journals (Sweden)

Thomas S A Wallis

Full Text Available BACKGROUND: Motion-defined form can seem to persist briefly after motion ceases, before seeming to gradually disappear into the background. Here we investigate if this subjective persistence reflects a signal capable of improving objective measures of sensitivity to static form. METHODOLOGY/PRINCIPAL FINDINGS: We presented a sinusoidal modulation of luminance, masked by a background noise pattern. The sinusoidal luminance modulation was usually subjectively invisible when static, but visible when moving. We found that drifting then stopping the waveform resulted in a transient subjective persistence of the waveform in the static display. Observers' objective sensitivity to the position of the static waveform was also improved after viewing moving waveforms, compared to viewing static waveforms for a matched duration. This facilitation did not occur simply because movement provided more perspectives of the waveform, since performance following pre-exposure to scrambled animations did not match that following pre-exposure to smooth motion. Observers did not simply remember waveform positions at motion offset, since removing the waveform before testing reduced performance. CONCLUSIONS/SIGNIFICANCE: Motion processing therefore interacts with subsequent static visual inputs in a way that can improve performance in objective sensitivity measures. We suggest that the brief subjective persistence of motion-defined forms that can occur after motion offsets is a consequence of the decay of a static form signal that has been transiently enhanced by motion processing.

Low-temperature fuel cells operating with contaminated feedstock

NARCIS (Netherlands)

Wingelaar, P.J.H.

2007-01-01

This work concerns the analysis and modeling of the dynamic and static behavior of Polymer Electrolyte Membrane Fuel Cells (PEMFC). Three fundamentally different measurement methods are used to determine the static, the large-signal, and the small-signal dynamic behavior of a fuel cell system. By

Adjustable static and dynamic actuation of clamped-guided beams using electrothermal axial loads

KAUST Repository

Alcheikh, Nouha

2018-02-14

The paper presents adjustable static and dynamic actuations of in-plane clamped-guided beams. The structures, of variable stiffness, can be used as highly tunable resonators and actuators. Axial loads are applied through electrothermal U-shaped and flexure beams actuators stacked near the edges of curved (arch) beams. The electrothermal actuators can be configurred in various ways to adjust as desired the mechanical stiffness of the structures; thereby controlling their deformation stroke as actuators and their operating resonance frequency as resonators. The experimental and finite element results demonstrate the flexibility of the designs in terms of static displacements and resonance frequencies of the first and second symmetric modes of the arches. The results show considerable increase in the resonance frequency and deflection of the microbeam upon changing end actuation conditions, which can be promising for low voltage actuation and tunable resonators applications, such as filters and memory devices. As case studies of potential device configurations of the proposed design, we demonstrate eight possibilities of achieving new static and dynamic behaviors, which produce various resonance frequencies and static displacement curves. The ability to actively shift the entire frequency response curve of a device is desirable for several applications to compensate for in-use anchor degradations and deformations. As an example, we experimentally demonstrate using the device as a resonant logic gate, with active resonance tuning, showing fundamental 2-bit logic functions, such as AND,XOR, and NOR.

Adjustable static and dynamic actuation of clamped-guided beams using electrothermal axial loads

KAUST Repository

Alcheikh, Nouha; Tella, Sherif Adekunle; Younis, Mohammad I.

2018-01-01

The paper presents adjustable static and dynamic actuations of in-plane clamped-guided beams. The structures, of variable stiffness, can be used as highly tunable resonators and actuators. Axial loads are applied through electrothermal U-shaped and flexure beams actuators stacked near the edges of curved (arch) beams. The electrothermal actuators can be configurred in various ways to adjust as desired the mechanical stiffness of the structures; thereby controlling their deformation stroke as actuators and their operating resonance frequency as resonators. The experimental and finite element results demonstrate the flexibility of the designs in terms of static displacements and resonance frequencies of the first and second symmetric modes of the arches. The results show considerable increase in the resonance frequency and deflection of the microbeam upon changing end actuation conditions, which can be promising for low voltage actuation and tunable resonators applications, such as filters and memory devices. As case studies of potential device configurations of the proposed design, we demonstrate eight possibilities of achieving new static and dynamic behaviors, which produce various resonance frequencies and static displacement curves. The ability to actively shift the entire frequency response curve of a device is desirable for several applications to compensate for in-use anchor degradations and deformations. As an example, we experimentally demonstrate using the device as a resonant logic gate, with active resonance tuning, showing fundamental 2-bit logic functions, such as AND,XOR, and NOR.

Natural Killer Dendritic Cells Enhance Immune Responses Elicited by α-Galactosylceramide-Stimulated Natural Killer T Cells

Directory of Open Access Journals (Sweden)

Sung Won Lee

2013-01-01

Full Text Available Natural killer dendritic cells (NKDCs possess potent anti-tumor activity, but the cellular effect of NKDC interactions with other innate immune cells is unclear. In this study, we demonstrate that the interaction of NKDCs and natural killer T (NKT cells is required for the anti-tumor immune responses that are elicited by α-galactosylceramide (α-GC in mice. The rapid and strong expression of interferon-γ by NKDCs after α-GC stimulation was dependent on NKT cells. Various NK and DC molecular markers and cytotoxic molecules were up-regulated following α-GC administration. This up-regulation could improve NKDC presentation of tumor antigens and increase cytotoxicity against tumor cells. NKDCs were required for the stimulation of DCs, NK cells, and NKT cells. The strong anti-tumor immune responses elicited by α-GC may be due to the down-regulation of regulatory T cells. Furthermore, the depletion of NKDCs dampened the tumor clearance mediated by α-GC-stimulated NKT cells in vivo. Taken together, these results indicate that complex interactions of innate immune cells might be required to achieve optimal anti-tumor immune responses during the early stages of tumorigenesis.

Osteogenic differentiation of MC3T3-E1 cells on poly(L-lactide)/Fe{sub 3}O{sub 4} nanofibers with static magnetic field exposure

Energy Technology Data Exchange (ETDEWEB)

Cai, Qing [State Key Laboratory of Organic–inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Shi, Yuzhou; Shan, Dingying; Jia, Wenkai; Duan, Shun [Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Deng, Xuliang [Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081 (China); Yang, Xiaoping, E-mail: yangxp@mail.buct.edu.cn [State Key Laboratory of Organic–inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029 (China)

2015-10-01

Proliferation and differentiation of bone-related cells are modulated by many factors such as scaffold design, growth factor, dynamic culture system, and physical simulation. Nanofibrous structure and moderate-intensity (1 mT–1 T) static magnetic field (SMF) have been identified as capable of stimulating proliferation and differentiation of osteoblasts. Herein, magnetic nanofibers were prepared by electrospinning mixture solutions of poly(L-lactide) (PLLA) and ferromagnetic Fe{sub 3}O{sub 4} nanoparticles (NPs). The PLLA/Fe{sub 3}O{sub 4} composite nanofibers demonstrated homogeneous dispersion of Fe{sub 3}O{sub 4} NPs, and their magnetism depended on the contents of Fe{sub 3}O{sub 4} NPs. SMF of 100 mT was applied in the culture of MC3T3-E1 osteoblasts on pure PLLA and PLLA/Fe{sub 3}O{sub 4} composite nanofibers for the purpose of studying the effect of SMF on osteogenic differentiation of osteoblastic cells on magnetic nanofibrous scaffolds. On non-magnetic PLLA nanofibers, the application of external SMF could enhance the proliferation and osteogenic differentiation of MC3T3-E1 cells. In comparison with pure PLLA nanofibers, the incorporation of Fe{sub 3}O{sub 4} NPs could also promote the proliferation and osteogenic differentiation of MC3T3-E1 cells in the absence or presence of external SMF. The marriage of magnetic nanofibers and external SMF was found most effective in accelerating every aspect of biological behaviors of MC3T3-E1 osteoblasts. The findings demonstrated that the magnetic feature of substrate and microenvironment were applicable ways in regulating osteogenesis in bone tissue engineering. - Highlights: • Magnetic nanofibers containing well-dispersed Fe{sub 3}O{sub 4} nanoparticles were produced. • Static magnetic field (SMF) was applied to perform the culture of osteoblasts. • Osteogenic differentiation was enhanced on magnetic substrate with exposure to SMF.

Pheromone Static Routing Strategy for Complex Networks

Science.gov (United States)

Hu, Mao-Bin; Henry, Y. K. Lau; Ling, Xiang; Jiang, Rui

2012-12-01

We adopt the concept of using pheromones to generate a set of static paths that can reach the performance of global dynamic routing strategy [Phys. Rev. E 81 (2010) 016113]. The path generation method consists of two stages. In the first stage, a pheromone is dropped to the nodes by packets forwarded according to the global dynamic routing strategy. In the second stage, pheromone static paths are generated according to the pheromone density. The output paths can greatly improve traffic systems' overall capacity on different network structures, including scale-free networks, small-world networks and random graphs. Because the paths are static, the system needs much less computational resources than the global dynamic routing strategy.

Sawja: Static Analysis Workshop for Java

Science.gov (United States)

Hubert, Laurent; Barré, Nicolas; Besson, Frédéric; Demange, Delphine; Jensen, Thomas; Monfort, Vincent; Pichardie, David; Turpin, Tiphaine

Static analysis is a powerful technique for automatic verification of programs but raises major engineering challenges when developing a full-fledged analyzer for a realistic language such as Java. Efficiency and precision of such a tool rely partly on low level components which only depend on the syntactic structure of the language and therefore should not be redesigned for each implementation of a new static analysis. This paper describes the Sawja library: a static analysis workshop fully compliant with Java 6 which provides OCaml modules for efficiently manipulating Java bytecode programs. We present the main features of the library, including i) efficient functional data-structures for representing a program with implicit sharing and lazy parsing, ii) an intermediate stack-less representation, and iii) fast computation and manipulation of complete programs. We provide experimental evaluations of the different features with respect to time, memory and precision.

Microstructure and Deformation Response of TRIP-Steel Syntactic Foams to Quasi-Static and Dynamic Compressive Loads

Science.gov (United States)

Ehinger, David; Weise, Jörg; Baumeister, Joachim; Funk, Alexander; Krüger, Lutz; Martin, Ulrich

2018-01-01

The implementation of hollow S60HS glass microspheres and Fillite 106 cenospheres in a martensitically transformable AISI 304L stainless steel matrix was realized by means of metal injection molding of feedstock with varying fractions of the filler material. The so-called TRIP-steel syntactic foams were studied with respect to their behavior under quasi-static compression and dynamic impact loading. The interplay between matrix material behavior and foam structure was discussed in relation to the findings of micro-structural investigations, electron back scatter diffraction EBSD phase analyses and magnetic measurements. During processing, the cenospheres remained relatively stable retaining their shape while the glass microspheres underwent disintegration associated with the formation of pre-cracked irregular inclusions. Consequently, the AISI 304L/Fillite 106 syntactic foams exhibited a higher compression stress level and energy absorption capability as compared to the S60HS-containing variants. The α′ -martensite kinetic of the steel matrix was significantly influenced by material composition, strain rate and arising deformation temperature. The highest ferromagnetic α′-martensite phase fraction was detected for the AISI 304L/S60HS batches and the lowest for the TRIP-steel bulk material. Quasi-adiabatic sample heating, a gradual decrease in strain rate and an enhanced degree of damage controlled the mechanical deformation response of the studied syntactic foams under dynamic impact loading. PMID:29695107

Matching tomographic IMRT fields with static photon fields

International Nuclear Information System (INIS)

Sethi, A.; Leybovich, L.; Dogan, N.; Emami, B.

2001-01-01

The matching of abutting radiation fields presents a challenging problem in radiation therapy. Due to sharp penumbra of linear accelerator beams, small (1-2 mm) errors in field positioning can lead to large (>30%) hot or cold spots in the abutment region. With head and neck immobilization devices (thermoplastic mask/aquaplast) an average setup error of 3 mm has been reported. Therefore hot or cold spots approaching 50% of the prescription dose may occur along the matchline. Although abutting radiation fields have been investigated for static fields, there is no reported study regarding matching of tomographic IMRT and static fields. Compared to static fields, the matching of tomographic IMRT fields with static fields is more complicated. Since IMRT and static fields are planned on separate treatment planning computers, the dose in the abutment region is not specified. In addition, commonly used techniques for matching fields, such as feathering of junctions, are not practical. We have developed a method that substantially reduces dose inhomogeneity in the abutment region. In this method, a 'buffer zone' around the matchline was created and was included as part of the target for both IMRT and static field plans. In both fields, a small dose gradient (≤3%/mm) in the buffer zone was created. In the IMRT plan, the buffer zone was divided into three sections with dose varying from 83% to 25% of prescription dose. The static field dose profile was modified using either a specially designed physical (hard) or a dynamic (soft) wedge. When these modified fields were matched, the combined dose in the abutment region varied by ≤10% in the presence of setup errors spanning 4 mm (±2 mm) when the hard wedge was used and 10 mm (±5 mm) with the soft wedge

T-cell proliferative responses following sepsis in neonatal rats.

Science.gov (United States)

Dallal, Ousama; Ravindranath, Thyyar M; Choudhry, Mashkoor A; Kohn, Annamarie; Muraskas, Jonathan K; Namak, Shahla Y; Alattar, Mohammad H; Sayeed, Mohammed M

2003-01-01

Both experimental and clinical evidence suggest a suppression of T-cell function in burn and sepsis. The objective of the present study was to evaluate splenocyte and purified T-cell proliferative response and IL-2 production in septic neonatal rats. We also examined if alterations in T-cell proliferation and IL-2 production in neonatal sepsis is due to elevation in PGE2. PGE2 is known to play a significant role in T-cell suppression during sepsis in adults. Sepsis was induced in 15-day-old neonatal Sprague-Dawley rats by implanting 0.1 cm3 of fecal pellet impregnated with Escherichia coli (50 CFU) and Bacteroides fragilis (10(3) CFU). Animals receiving fecal pellets without the bacteria were designated as sterile. A group of septic and sterile rats were treated with PGE2 synthesis inhibitors, NS398 and resveratrol. These treatments of animals allowed us to evaluate the role of PGE2 in T-cell suppression during neonatal sepsis. Splenocytes as well as purified T cells were prepared and then proliferative response and IL-2 productive capacities were measured. A significant suppression of splenocyte proliferation and IL-2 production was noticed in both sterile and septic animals compared to the T cells from unoperated control rats. In contrast, the proliferation and IL-2 production by nylon wool purified T cells in sterile rats was not significantly different from control rats, whereas, a significant suppression in Con A-mediated T-cell proliferation and IL-2 production noticed in septic rat T cells compared to the sterile and control rat T cells. Such decrease in T-cell proliferation and IL-2 production was accompanied with 20-25% deaths in neonates implanted with septic pellets. No mortality was noted in sterile-implanted neonates. Treatment of animals with COX-1 inhibitor had no effect on T-cell proliferation response in both septic and sterile groups, whereas COX-2 inhibitor abrogated the decrease in T-cell proliferative response in the septic group. The treatment

Regulatory T Cells and Host Anti-CML Responses

National Research Council Canada - National Science Library

Wong, Jr, K. K

2008-01-01

CD4+CD25+FoxP-3+ regulatory T-cells (Tregs) suppress immune responses to "self" antigens, but also have been shown to suppress host anti-tumor responses in several human malignancies, including breast, gastrointestinal, and ovarian cancer...

Defective B cell response to T-dependent immunization in lupus-prone mice

Science.gov (United States)

Niu, Haitao; Sobel, Eric S.; Morel, Laurence

2009-01-01

Lupus anti-nuclear Abs show the characteristics of Ag-driven T cell-dependent (TD) humoral responses. If autoAgs elicit the same response as exogenous Ags, lupus should enhance humoral responses to immunization. Blunted responses to various immunizations have, however, been reported in a significant portion of lupus patients. In this study, we show that lupus-prone B6.Sle1.Sle2.Sle3 (B6.TC) mice produce significantly less Ab in response to TD immunization than congenic controls, while producing significantly more total Ig. This blunted Ab response to TD Ag could be reconstituted with B6.TC B and CD4+ T cells. Multiple defects were found in the B6.TC response to NP-KLH as compared to total Ig, including a smaller percentage of B cells participating to the NP-response, a reduced entry into germinal centers, and highly defective production of NP-specific long-lived plasma cells in the bone marrow. B6.TC plasma cells expressed reduced levels of FcγRIIb, which suggests that reduced apoptosis in resident plasma cells prevents the establishment of newly-formed NP-specific plasma cells in bone marrow niches. Overall, these results show that lupus-prone mice responded differently to auto- and exogenous antigens and suggest that low FcγRIIb, hypergammaglobulinemia and high autoantibody production would be predictive of a poor response to immunization in lupus patients. PMID:18924209

Investigation of two pitot-static tubes at supersonic speeds

Science.gov (United States)

Hasel, Lowell E; Coletti, Donald E

1948-01-01

The results of tests at a Mach number of 1.94 of an ogives-nose cylindrical pitot-static tube and similar tests at Mach numbers of 1.93 and 1.62 of a service pitot-static tube to determine body static pressures and indicated Mach numbers are presented and discussed. The radial pressure distribution on the cylindrical bodies is compared with that calculated by an approximate theory.

Quasi-static Design of Electrically Small Ultra-Wideband Antennas

Science.gov (United States)

2017-02-01

Equations. The ACD uses a constant line charge distribution and image line charge distribution (both on the -axis) to generate equipotential surfaces ...Each equipotential surface represents an ACD antenna design with a different height. In the Quasi-static Antenna Design Algorithm [2, 3, 4, 5, 6...quasi- static approximation used in the algorithm. A static charge distribution is used to generate equipotential surfaces . The equipotential surfaces

Genome wide transcriptional response of Saccharomyces cerevisiae to stress-induced perturbations

Directory of Open Access Journals (Sweden)

Hilal eTaymaz-Nikerel

2016-02-01

Full Text Available Cells respond to environmental and/or genetic perturbations in order to survive and proliferate. Characterization of the changes after various stimuli at different -omics levels is crucial to comprehend the adaptation of cells to changing conditions. Genome wide quantification and analysis of transcript levels, the genes affected by perturbations, extends our understanding of cellular metabolism by pointing out the mechanisms that play role in sensing the stress caused by those perturbations and related signaling pathways, and in this way guides us to achieve endeavors such as rational engineering of cells or interpretation of disease mechanisms. Saccharomyces cerevisiae as a model system has been studied in response to different perturbations and corresponding transcriptional profiles were followed either statically or/and dynamically, short- and long- term. This review focuses on response of yeast cells to diverse stress inducing perturbations including nutritional changes, ionic stress, salt stress, oxidative stress, osmotic shock, as well as to genetic interventions such as deletion and over-expression of genes. It is aimed to conclude on common regulatory phenomena that allow yeast to organize its transcriptomic response after any perturbation under different external conditions.

Electronic orbital response of regular extended and infinite periodic systems to magnetic fields. I. Theoretical foundations for static case

Science.gov (United States)

Springborg, Michael; Molayem, Mohammad; Kirtman, Bernard

2017-09-01

A theoretical treatment for the orbital response of an infinite, periodic system to a static, homogeneous, magnetic field is presented. It is assumed that the system of interest has an energy gap separating occupied and unoccupied orbitals and a zero Chern number. In contrast to earlier studies, we do not utilize a perturbation expansion, although we do assume the field is sufficiently weak that the occurrence of Landau levels can be ignored. The theory is developed by analyzing results for large, finite systems and also by comparing with the analogous treatment of an electrostatic field. The resulting many-electron Hamilton operator is forced to be hermitian, but hermiticity is not preserved, in general, for the subsequently derived single-particle operators that determine the electronic orbitals. However, we demonstrate that when focusing on the canonical solutions to the single-particle equations, hermiticity is preserved. The issue of gauge-origin dependence of approximate solutions is addressed. Our approach is compared with several previously proposed treatments, whereby limitations in some of the latter are identified.

Single event upset in static random access memories in atmospheric neutron environments

CERN Document Server

Arita, Y; Ogawa, I; Kishimoto, T

2003-01-01

Single-event upsets (SEUs) in a 0.4 mu m 4Mbit complementary metal oxide semiconductor (CMOS) static random access memory (SRAM) were investigated in various atmospheric neutron environments at sea level, at an altitude of 2612 m mountain, at an altitude of commercial airplane, and at an underground depth of 476m. Neutron-induced SEUs increase with the increase in altitude. For a device with a borophosphosilicate glass (BPSG) film, SEU rates induced by thermal neutrons increase with the decrease in the cell charge of a memory cell. A thermal neutron-induced SEU is significant in SRAMs with a small cell charge. With the conditions of small cell charge, thermal neutron-induced SEUs account for 60% or more of the total neutron-induced SEUs. The SEU rate induced by atmospheric thermal neutrons can be estimated by an acceleration test using sup 2 sup 5 sup 2 Cf. (author)

Spin-orbit coupling and the static polarizability of single-wall carbon nanotubes

International Nuclear Information System (INIS)

Diniz, Ginetom S.; Ulloa, Sergio E.

2014-01-01

We calculate the static longitudinal polarizability of single-wall carbon tubes in the long wavelength limit taking into account spin-orbit effects. We use a four-orbital orthogonal tight-binding formalism to describe the electronic states and the random phase approximation to calculate the dielectric function. We study the role of both the Rashba as well as the intrinsic spin-orbit interactions on the longitudinal dielectric response, i.e., when the probing electric field is parallel to the nanotube axis. The spin-orbit interaction modifies the nanotube electronic band dispersions, which may especially result in a small gap opening in otherwise metallic tubes. The bandgap size and state features, the result of competition between Rashba and intrinsic spin-orbit interactions, result in drastic changes in the longitudinal static polarizability of the system. We discuss results for different nanotube types and the dependence on nanotube radius and spin-orbit couplings.

Spin-orbit coupling and the static polarizability of single-wall carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Diniz, Ginetom S., E-mail: ginetom@gmail.com; Ulloa, Sergio E. [Department of Physics and Astronomy and Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701-2979 (United States)

2014-07-14

We calculate the static longitudinal polarizability of single-wall carbon tubes in the long wavelength limit taking into account spin-orbit effects. We use a four-orbital orthogonal tight-binding formalism to describe the electronic states and the random phase approximation to calculate the dielectric function. We study the role of both the Rashba as well as the intrinsic spin-orbit interactions on the longitudinal dielectric response, i.e., when the probing electric field is parallel to the nanotube axis. The spin-orbit interaction modifies the nanotube electronic band dispersions, which may especially result in a small gap opening in otherwise metallic tubes. The bandgap size and state features, the result of competition between Rashba and intrinsic spin-orbit interactions, result in drastic changes in the longitudinal static polarizability of the system. We discuss results for different nanotube types and the dependence on nanotube radius and spin-orbit couplings.

The radiation response of cells recovering after chronic hypoxia

International Nuclear Information System (INIS)

Kwok, T.T.; Sutherland, R.M.

1989-01-01

Experiments were performed to study the influence of hypoxic pretreatment on the radiation response of A431 human squamous carcinoma cells. Reaeration for 10 min after chronic hypoxia (greater than 2 h) was found to enhance the radiosensitivity of A431 cells, and the maximal effect was seen for those cells reaerated after 12 h of hypoxia. The radiosensitivity enhancement for reaerated cells after 12 h of hypoxia was maximized by 5 min after the return to aerobic conditions and reached the control level by 12 h of reaeration. This enhanced radiosensitive state was characterized by a reduced shoulder region and increased slope of the radiation dose-response curve for cells in both the exponential and plateau phases of growth. There was a slight increase in the number of G1 and decrease in the number of S and G2 + M cells for both exponential- and plateau-phase cultures following 12 h hypoxic treatment. Although growth inhibition induced by 12 h of hypoxia was seen for cells in the exponential phase, there was no cell number change in the plateau-phase culture after hypoxia. Plating efficiency (PE) of cells in both growth phases was reduced by 30% after hypoxia. Furthermore, in the exponential-phase culture, the extent of reduction in PE after hypoxia was similar among cells in different phases of the cell cycle. Although S-phase cells in exponentially growing cultures were relatively more resistant to radiation than G1 and G2 + M cells, the cell age-response pattern was the same whether the cells had been aerobic or hypoxic before reaeration and irradiation. Furthermore, the enhancement ratio associated with reaeration after 12 h of hypoxia for these three subpopulations of cells was 1.3. Our results indicate that the increase in radiosensitivity due to reaeration after chronic hypoxia is unlikely to be related to the changes of cell cycle stage and growth phase during hypoxic treatment

Static quarks with improved statistical precision

International Nuclear Information System (INIS)

Della Morte, M.; Duerr, S.; Molke, H.; Heitger, J.

2003-09-01

We present a numerical study for different discretisations of the static action, concerning cut-off effects and the growth of statistical errors with Euclidean time. An error reduction by an order of magnitude can be obtained with respect to the Eichten-Hill action, for time separations up to 2 fm, keeping discretization errors small. The best actions lead to a big improvement on the precision of the quark mass M b and F B s in the static approximation. (orig.)

Regulation of T Cell Homeostasis and Responses by Pten

Directory of Open Access Journals (Sweden)

Ryan H. Newton

2012-06-01

Full Text Available The generation of lipid products catalyzed by PI3K is critical for normal T cell homeostasis and a productive immune response. PI3K can be activated in response to antigen receptor, costimulatory, cytokine and chemokine signals. Moreover, dysregulation of this pathway frequently occurs in T cell lymphomas and is implicated in lymphoproliferative autoimmune disease. Akt acts as a central mediator of PI3K signals, downstream of which is the mTOR pathway, controlling cell growth and metabolism. Members of the Foxo family of transcription factors are also regulated by Akt, thus linking control over homing and migration of T cells, as well cell cycle entry, apoptosis, and DNA damage and oxidative stress responses, to PI3K signaling. PTEN, first identified as a tumor suppressor gene, encodes a lipid phosphatase that, by catalyzing the reverse of the PI3K reaction, directly opposes PI3K signaling. However, PTEN may have other functions as well, and recent reports have suggested roles for PTEN as a tumor suppressor independent of its effects on PI3K signaling. Through the use of models in which Pten is deleted specifically in T cells, it is becoming increasingly clear that control over autoimmunity and lymphomagenesis by PTEN involves multi-faceted functions of this molecule at multiple stages of T cell development.

Cytokines and the Inception of CD8 T Cell Responses

Science.gov (United States)

Cox, Maureen A.; Harrington, Laurie E.; Zajac, Allan J.

2011-01-01

The activation and differentiation of CD8 T cells is a necessary first step that endows these cells with the phenotypic and functional properties required for the control of intracellular pathogens. The induction of the CD8 T cell responses typically results in the development of a massive overall population of effector cells, comprised of both highly functional but short-lived terminally differentiated cells, as well as a smaller subset of precursors that are predisposed to survive and transition into the memory T cell pool. In this article we discuss how inflammatory cytokines and IL-2 bias the initial response towards short-lived effector generation and also highlight the potential counterbalancing role of IL-21. PMID:21371940

Radiation responses of stem cells: targeted and non-targeted effects

International Nuclear Information System (INIS)

Kavanagh, J.N.; Waring, E.J.; Prise, K.M.

2015-01-01

Stem cells are fundamental to the development of any tissue or organism via their ability to self-renew, which is aided by their unlimited proliferative capacity and their ability to produce fully differentiated offspring, often from multiple lineages. Stems cells are long lived and have the potential to accumulate mutations, including in response to radiation exposure. It is thought that stem cells have the potential to be induced into a cancer stem cell phenotype and that these may play an important role in resistance to radiotherapy. For radiation-induced carcinogenesis, the role of targeted and non-targeted effects is unclear with tissue or origin being important. Studies of genomic instability and bystander responses have shown consistent effects in haematopoietic models. Several models of radiation have predicted that stem cells play an important role in tumour initiation and that bystander responses could play a role in proliferation and self-renewal. (authors)

Interaction of biological systems with static and ELF electric and magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Anderson, L.E.; Kelman, B.J.; Weigel, R.J. (eds.)

1987-01-01

Although background levels of atmospheric electric and geomagnetic field levels are extremely low, over the past several decades, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milieu. An exponential increase in exposure to electromagnetic fields has occurred, largely because of such technological advances as the growth of electrical power generation and transmission systems, the increased use of wireless communications, and the use of radar. In addition, electromagnetic field generating devices have proliferated in industrial plants, office buildings, homes, public transportation systems, and elsewhere. Although significant increases have occurred in electromagnetic field strenghths spanning all frequency ranges, this symposium addresses only the impact of these fields at static and extremely low frequencies (ELF), primarily 50 and 60 Hz. This volume contains the proceedings of the symposium entitled /open quotes/Interaction of biological systems with static and ELF electric and magnetic fields/close quotes/. The purpose of the symposium was to provide a forum for discussions of all aspects of research on the interaction of static and ELF electromagnetic fields with biological systems. These systems include simple biophysical models, cell and organ preparations, whole animals, and man. Dosimetry, exposure system design, and artifacts in ELF bioeffects research were also addressed, along with current investigations that examine fundamental mechanisms of interactions between the fields and biological processes. Papers are indexed separately.

Interaction with Epithelial Cells Modifies Airway Macrophage Response to Ozone

Science.gov (United States)

The initial innate immune response to ozone (03) in the lung is orchestrated by structural cells, such as epithelial cells, and resident immune cells, such as airway macrophages (Macs). We developed an epithelial cell-Mac coculture model to investigate how epithelial cell-derived...

Quasi-static and dynamic forced shear deformation behaviors of Ti-5Mo-5V-8Cr-3Al alloy

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhiming; Chen, Zhiyong, E-mail: czysh@netease.com; Zhan, Congkun; Kuang, Lianjun; Shao, Jianbo; Wang, Renke; Liu, Chuming

2017-04-13

The mechanical behavior and microstructure characteristics of Ti-5Mo-5V-8Cr-3Al alloy were investigated with hat-shaped samples compressed under quasi-static and dynamic loading. Compared with the quasi-static loading, a higher shear stress peak and a shear instability stage were observed during the dynamic shear response. The results showed that an adiabatic shear band consisting of ultrafine equiaxed grains was only developed in the dynamic specimen, while a wider shear region was formed in the quasi-static specimen. The microhardness measurements revealed that shear region in the quasi-static specimen and adiabatic shear band in the dynamic specimen exhibited higher hardness than that of adjacent regions due to the strain hardening and grain refining, respectively. A stable orientation, in which the crystallographic {110} planes and <111> directions were respectively parallel to the shear plane and shear direction, developed in both specimens. And the microtexture of the adiabatic shear band was more well-defined than that of the shear region in the quasi-static specimen. Rotational dynamic recrystallization mechanism was suggested to explain the formation of ultrafine equiaxed grains within the adiabatic shear band by thermodynamic and kinetic calculations.

The performance of a soluble lead-acid flow battery and its comparison to a static lead-acid battery

International Nuclear Information System (INIS)

Zhang, C.P.; Sharkh, S.M.; Li, X.; Walsh, F.C.; Zhang, C.N.; Jiang, J.C.

2011-01-01

Highlights: → We compared the electrochemical characteristics of two types of the batteries. → SLAFB shows as good performance as SLAB under the same current density. → The cycle life of two batteries is strongly influenced by the depth of discharge. → The cycle life of SLAFB can be extended by treatment with hydrogen peroxide. - Abstract: The electrochemistry of static lead-acid and soluble lead-acid flow batteries is summarised and the differences between the two batteries are highlighted. A general comparison of the performance of an unoptimised soluble lead-acid flow laboratory cell and a commercial lead-acid battery during charge and discharge is reported. The influence of the depth of discharge on cycle life for both batteries is also considered. The flow battery was found to have a better charge efficiency than the static one, but the cells were found to have comparable energy efficiencies. The self-discharge characteristics of the soluble lead-acid battery were also measured and compared to reported values for a commercial static battery. Some self-discharge of the soluble lead-acid flow battery is observed during prolonged periods on open-circuit but the battery could recover its normal performance after a single charge-discharge cycle.

Modulation of Immune Responses by Exosomes Derived from Antigen-Presenting Cells

Directory of Open Access Journals (Sweden)

Botros B. Shenoda

2016-01-01

Full Text Available Exosome-mediated signaling is important in mediating the inflammatory response. To exert their biological or pathophysiological functions in the recipient cells, exosomes deliver a diverse array of biomacromolecules including long and short coding and non-coding RNAs, proteins, and lipids. Exosomes secreted by antigen-presenting cells can confer therapeutic benefits by attenuating or stimulating the immune response. Exosomes play a crucial role in carrying and presenting functional major histocompatibility peptide complexes to modulate antigen-specific T cell responses. Exosomes from Dendritic Cells (DCs can activate T and B cells and have been explored for their immunostimulatory properties in cancer therapy. The immunosuppressive properties of exosomes derived from macrophages and DCs can reduce inflammation in animal models for several inflammatory disorders. This review focuses on the protective role of exosomes in attenuating inflammation or augmenting immune response, emphasizing studies on exosomes derived from DCs and macrophages.

Spectral response of a polycrystalline silicon solar cell

International Nuclear Information System (INIS)

Ba, B.; Kane, M.

1994-10-01

A theoretical study of the spectral response of a polycrystalline silicon n-p junction solar cell is presented. The case of a fibrously oriented grain structure, involving grain boundary recombination velocity and grain size effects is discussed. The contribution of the base region on the internal quantum efficiency Q int is computed for different grain sizes and grain boundary recombination velocities in order to examine their influence. Suggestions are also made for the determination of base diffusion length in polycrystalline silicon solar cells using the spectral response method. (author). 15 refs, 4 figs

The effects of static friction and backlash on extended physiological proprioception control of a powered prosthesis.

Science.gov (United States)

Farrell, Todd R; Weir, Richard F; Heckathorne, Craig W; Childress, Dudley S

2005-01-01

In general, externally powered prostheses do not provide proprioceptive feedback and thus require the user to rely on cognitively expensive visual feedback to effectively control the prosthesis. Applying the concept of extended physiological proprioception (EPP) to externally powered prostheses provides direct feedback to the user's proprioceptive system regarding the position, velocity, and forces applied to the prosthesis. However, electric elbows with EPP controllers developed at the Northwestern University Prosthetics Research Laboratory have exhibited unexplained "jerky" behavior in both clinical fittings and bench-top operation. In addition, the development of limit cycles, a specific type of constant-amplitude oscillation, had been observed in bench-top use of these elbows. Backlash and static friction within the EPP system were found to be primarily responsible for the development of limit cycles. Reducing static friction and backlash improved the system's performance. These results suggest that to most effectively implement EPP, prosthesis manufacturers should design prosthetic components that minimize static friction and backlash.

Tools and Workflows for Collaborating on Static Website Projects

Directory of Open Access Journals (Sweden)

Kaitlin Newson

2017-10-01

Full Text Available Static website generators have seen a significant increase in popularity in recent years, offering many advantages over their dynamic counterparts. While these generators were typically used for blogs, they have grown in usage for other web-based projects, including documentation, conference websites, and image collections. However, because of their technical complexity, these tools can be inaccessible to content creators depending on their level of technical skill and comfort with web development technologies. Drawing from experience with a collaborative static website project, this article will provide an overview of static website generators, review different tools available for managing content, and explore workflows and best practices for collaborating with teams on static website projects.

Unraveling the response of plant cells to cytotoxic saponins

Science.gov (United States)

Balestrazzi, Alma; Macovei, Anca; Tava, Aldo; Avato, Pinarosa; Raimondi, Elena

2011-01-01

A wide range of pharmacological properties are ascribed to natural saponins, in addition to their biological activities against herbivores, plant soil-borne pathogens and pests. As for animal cells, the cytotoxicity and the chemopreventive role of saponins are mediated by a complex network of signal transduction pathways which include reactive oxygen species (ROS) and nitric oxide (NO). The involvement of other relevant components of the saponin-related signaling routes, such as the Tumor Necrosis Factor (TNF)α, the interleukin (IL)-6 and the Nuclear Transcription FactorκB (NFκB), has been highlighted in animal cells. By contrast, information concerning the response of plant cells to saponins and the related signal transduction pathways is almost missing. To date, there are only a few common features which link plant and animal cells in their response to saponins, such as the early burst in ROS and NO production and the induction of metallothioneins (MTs), small cysteine-rich, metal-binding proteins. This aspect is discussed in the present paper in view of the recent hypothesis that MTs and NO are part of a novel signal transduction pathway participating in the cell response to oxidative stress. PMID:21673512

Cross-talk between cd1d-restricted nkt cells and γδ cells in t regulatory cell response

Directory of Open Access Journals (Sweden)

Huber Sally A

2011-01-01

Full Text Available Abstract CD1d is a non-classical major histocompatibility class 1-like molecule which primarily presents either microbial or endogenous glycolipid antigens to T cells involved in innate immunity. Natural killer T (NKT cells and a subpopulation of γδ T cells expressing the Vγ4 T cell receptor (TCR recognize CD1d. NKT and Vγ4 T cells function in the innate immune response via rapid activation subsequent to infection and secrete large quantities of cytokines that both help control infection and modulate the developing adaptive immune response. T regulatory cells represent one cell population impacted by both NKT and Vγ4 T cells. This review discusses the evidence that NKT cells promote T regulatory cell activation both through direct interaction of NKT cell and dendritic cells and through NKT cell secretion of large amounts of TGFβ, IL-10 and IL-2. Recent studies have shown that CD1d-restricted Vγ4 T cells, in contrast to NKT cells, selectively kill T regulatory cells through a caspase-dependent mechanism. Vγ4 T cell elimination of the T regulatory cell population allows activation of autoimmune CD8+ effector cells leading to severe cardiac injury in a coxsackievirus B3 (CVB3 myocarditis model in mice. CD1d-restricted immunity can therefore lead to either immunosuppression or autoimmunity depending upon the type of innate effector dominating during the infection.

An Abbreviated Protocol for In Vitro Generation of Functional Human Embryonic Stem Cell-Derived Beta-Like Cells.

Directory of Open Access Journals (Sweden)

Mohammad Massumi

Full Text Available The ability to yield glucose-responsive pancreatic beta-cells from human pluripotent stem cells in vitro will facilitate the development of the cell replacement therapies for the treatment of Type 1 Diabetes. Here, through the sequential in vitro targeting of selected signaling pathways, we have developed an abbreviated five-stage protocol (25-30 days to generate human Embryonic Stem Cell-Derived Beta-like Cells (ES-DBCs. We showed that Geltrex, as an extracellular matrix, could support the generation of ES-DBCs more efficiently than that of the previously described culture systems. The activation of FGF and Retinoic Acid along with the inhibition of BMP, SHH and TGF-beta led to the generation of 75% NKX6.1+/NGN3+ Endocrine Progenitors. The inhibition of Notch and tyrosine kinase receptor AXL, and the treatment with Exendin-4 and T3 in the final stage resulted in 35% mono-hormonal insulin positive cells, 1% insulin and glucagon positive cells and 30% insulin and NKX6.1 co-expressing cells. Functionally, ES-DBCs were responsive to high glucose in static incubation and perifusion studies, and could secrete insulin in response to successive glucose stimulations. Mitochondrial metabolic flux analyses using Seahorse demonstrated that the ES-DBCs could efficiently metabolize glucose and generate intracellular signals to trigger insulin secretion. In conclusion, targeting selected signaling pathways for 25-30 days was sufficient to generate ES-DBCs in vitro. The ability of ES-DBCs to secrete insulin in response to glucose renders them a promising model for the in vitro screening of drugs, small molecules or genes that may have potential to influence beta-cell function.

Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining: A review

Directory of Open Access Journals (Sweden)

Xibing Li

2017-08-01

Full Text Available Rock failure phenomena, such as rockburst, slabbing (or spalling and zonal disintegration, related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining. Currently, the explanation for these failure phenomena using existing dynamic or static rock mechanics theory is not straightforward. In this study, new theory and testing method for deep underground rock mass under coupled static-dynamic loading are introduced. Two types of coupled loading modes, i.e. “critical static stress + slight disturbance” and “elastic static stress + impact disturbance”, are proposed, and associated test devices are developed. Rockburst phenomena of hard rocks under coupled static-dynamic loading are successfully reproduced in the laboratory, and the rockburst mechanism and related criteria are demonstrated. The results of true triaxial unloading compression tests on granite and red sandstone indicate that the unloading can induce slabbing when the confining pressure exceeds a certain threshold, and the slabbing failure strength is lower than the shear failure strength according to the conventional Mohr-Column criterion. Numerical results indicate that the rock unloading failure response under different in situ stresses and unloading rates can be characterized by an equivalent strain energy density. In addition, we present a new microseismic source location method without premeasuring the sound wave velocity in rock mass, which can efficiently and accurately locate the rock failure in hard rock mines. Also, a new idea for deep hard rock mining using a non-explosive continuous mining method is briefly introduced.

Reproducible fashion of the HSP70B' promoter-induced cytotoxic response on a live cell-based biosensor by cell cycle synchronization.

Science.gov (United States)

Migita, Satoshi; Wada, Ken-Ichi; Taniguchi, Akiyoshi

2010-10-15

Live cell-based sensors potentially provide functional information about the cytotoxic effect of reagents on various signaling cascades. Cells transfected with a reporter vector derived from a cytotoxic response promoter can be used as intelligent cytotoxicity sensors (i.e., sensor cells). We have combined sensor cells and a microfluidic cell culture system that can achieve several laminar flows, resulting in a reliable high-throughput cytotoxicity detection system. These sensor cells can also be applied to single cell arrays. However, it is difficult to detect a cellular response in a single cell array, due to the heterogeneous response of sensor cells. The objective of this study was cell homogenization with cell cycle synchronization to enhance the response of cell-based biosensors. Our previously established stable sensor cells were brought into cell cycle synchronization under serum-starved conditions and we then investigated the cadmium chloride-induced cytotoxic response at the single cell level. The GFP positive rate of synchronized cells was approximately twice as high as that of the control cells, suggesting that cell homogenization is an important step when using cell-based biosensors with microdevices, such as a single cell array. Copyright 2010 Wiley Periodicals, Inc.

The intersection between DNA damage response and cell death pathways.

Science.gov (United States)

Nowsheen, S; Yang, E S

2012-10-01

Apoptosis is a finely regulated process that serves to determine the fate of cells in response to various stresses. One such stress is DNA damage, which not only can signal repair processes but is also intimately involved in regulating cell fate. In this review we examine the relationship between the DNA damage/repair response in cell survival and apoptosis following insults to the DNA. Elucidating these pathways and the crosstalk between them is of great importance, as they eventually contribute to the etiology of human disease such as cancer and may play key roles in determining therapeutic response. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later".

Skin-Resident T Cells Drive Dermal Dendritic Cell Migration in Response to Tissue Self-Antigen.

Science.gov (United States)

Ali, Niwa; Zirak, Bahar; Truong, Hong-An; Maurano, Megan M; Gratz, Iris K; Abbas, Abul K; Rosenblum, Michael D

2018-05-01

Migratory dendritic cell (DC) subsets deliver tissue Ags to draining lymph nodes (DLNs) to either initiate or inhibit T cell-mediated immune responses. The signals mediating DC migration in response to tissue self-antigen are largely unknown. Using a mouse model of inducible skin-specific self-antigen expression, we demonstrate that CD103 + dermal DCs (DDCs) rapidly migrate from skin to skin DLN (SDLNs) within the first 48 h after Ag expression. This window of time was characterized by the preferential activation of tissue-resident Ag-specific effector T cells (Teffs), with no concurrent activation of Ag-specific Teffs in SDLNs. Using genetic deletion and adoptive transfer approaches, we show that activation of skin-resident Teffs is required to drive CD103 + DDC migration in response to tissue self-antigen and this Batf3-dependent DC population is necessary to mount a fulminant autoimmune response in skin. Conversely, activation of Ag-specific Teffs in SDLNs played no role in DDC migration. Our studies reveal a crucial role for skin-resident T cell-derived signals, originating at the site of self-antigen expression, to drive DDC migration during the elicitation phase of an autoimmune response. Copyright © 2018 by The American Association of Immunologists, Inc.

Modulation of immune response by alloactivated suppressor T cells

International Nuclear Information System (INIS)

Bernstein, A.; Sopori, M.L.; Gose, J.E.; Sondel, P.M.

1979-01-01

These studies show that there may be several different kinds of suppressor cells, each activated by different pathways and able to suppress different parts of the immune response either specifically or nonspecifically. As such, the physiology of one type of suppressor cell need not necessarily apply to that of another type of suppressor. Thus we emphasize the trap that the suppressor cell option provides: that is, virtually any previously inexplicable in vitro and in vivo immune phenomenon can always be adequately accounted for by evoking a suppressor mechanism, either by suppressing the response or suppressing the suppressor

de Sitter relativity in static charts

Energy Technology Data Exchange (ETDEWEB)

Cotaescu, Ion I. [West University of Timisoara, Timisoara (Romania)

2018-02-15

The relative geodesic motion in static (and spherically symmetric) local charts on the (1 + 3)-dimensional de Sitter spacetimes is studied in terms of conserved quantities. The Lorentzian isometries are derived, relating the coordinates of the local chart of a fixed observer with the coordinates of a mobile chart considered as the rest frame of a massive particle freely moving on a timelike geodesic. The time dilation and Lorentz contraction are discussed pointing out some notable features of the de Sitter relativity in static charts. (orig.)

Survey of approaches for handling static analysis alarms

NARCIS (Netherlands)

Muske, T.; Serebrenik, A.

2016-01-01

Static analysis tools have showcased their importance and usefulness in automated detection of code anomalies and defects. However, the large number of alarms reported and cost incurred in their manual inspections have been the major concerns with the usage of static analysis tools. Existing studies

Multiple histogram method and static Monte Carlo sampling

NARCIS (Netherlands)

Inda, M.A.; Frenkel, D.

2004-01-01

We describe an approach to use multiple-histogram methods in combination with static, biased Monte Carlo simulations. To illustrate this, we computed the force-extension curve of an athermal polymer from multiple histograms constructed in a series of static Rosenbluth Monte Carlo simulations. From

Short-term, serum-free, static culture of cord blood-derived CD34+ cells: effects of FLT3-L and MIP-1alpha on in vitro expansion of hematopoietic progenitor cells.

Science.gov (United States)

Capmany, G; Querol, S; Cancelas, J A; García, J

1999-08-01

The use of ex vivo expanded cells has been suggested as a possible means to accelerate the speed of engraftment in cord blood (CB) transplantation. The aim of this study was to fix the optimal condition for the generation of committed progenitors without affecting the stem cell compartment. Analysis of the effects of FLT3-L and MIP-1alpha when combined with SCF, IL-3 and IL-6, in short-term (6 days), serum-free expansion cultures of CB-selected CD34+ cells. An important expansion was obtained that ranged between 8-15 times for CFU-GM, 21-51 times for the BFU-E/CFU-Mix population and 11 to 30 times for CD34+ cells assessed by flow cytometry. From the combinations tested, those in which FLT3-L was present had a significant increase in the expansion of committed progenitors, while the presence of MIP-1alpha had a detrimental effect on the generation of more differentiated cells. However, stem cell candidates assessed by week 5 CAFC assay could be maintained in culture when both MIP-1a and FLT3-L were present (up to 91% recovery). This culture system was also able to expand megakaryocytic precursors as determined by the co-expression of CD34 and CD61 antigens (45-70 times), in spite of the use of cytokines non-specific for the megakaryocytic lineage. The results obtained point to the combination of SCF, IL-3, IL-6, FLT3-L and MIP-1alpha as the best suited for a pre-clinical short-term serum-free static ex vivo expansion protocol of CB CD34+ cells, since it can generate large numbers of committed progenitor cells as well as maintaining week 5 CAFC.

Thermo-responsive cell culture carrier: Effects on macrophage functionality and detachment efficiency.

Science.gov (United States)

Rennert, Knut; Nitschke, Mirko; Wallert, Maria; Keune, Natalie; Raasch, Martin; Lorkowski, Stefan; Mosig, Alexander S

2017-01-01

Harvesting cultivated macrophages for tissue engineering purposes by enzymatic digestion of cell adhesion molecules can potentially result in unintended activation, altered function, or behavior of these cells. Thermo-responsive polymer is a promising tool that allows for gentle macrophage detachment without artificial activation prior to subculture within engineered tissue constructs. We therefore characterized different species of thermo-responsive polymers for their suitability as cell substrate and to mediate gentle macrophage detachment by temperature shift. Primary human monocyte- and THP-1-derived macrophages were cultured on thermo-responsive polymers and characterized for phagocytosis and cytokine secretion in response to lipopolysaccharide stimulation. We found that both cell types differentially respond in dependence of culture and stimulation on thermo-responsive polymers. In contrast to THP-1 macrophages, primary monocyte-derived macrophages showed no signs of impaired viability, artificial activation, or altered functionality due to culture on thermo-responsive polymers compared to conventional cell culture. Our study demonstrates that along with commercially available UpCell carriers, two other thermo-responsive polymers based on poly(vinyl methyl ether) blends are attractive candidates for differentiation and gentle detachment of primary monocyte-derived macrophages. In summary, we observed similar functionality and viability of primary monocyte-derived macrophages cultured on thermo-responsive polymers compared to standard cell culture surfaces. While this first generation of custom-made thermo-responsive polymers does not yet outperform standard culture approaches, our results are very promising and provide the basis for exploiting the unique advantages offered by custom-made thermo-responsive polymers to further improve macrophage culture and recovery in the future, including the covalent binding of signaling molecules and the reduction of

Nanosecond electric pulses trigger actin responses in plant cells

International Nuclear Information System (INIS)

Berghoefer, Thomas; Eing, Christian; Flickinger, Bianca; Hohenberger, Petra; Wegner, Lars H.; Frey, Wolfgang; Nick, Peter

2009-01-01

We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

Directory of Open Access Journals (Sweden)

Murray Elaine

2009-04-01

Full Text Available Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM. 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1 at baseline; (2 after warm-up; (3 after stretch (static or dynamic and (4 after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Results Across both groups, there was a significant main effect for time (p 0.05. Using ANCOVA to adjust for the non-significant (p = 0.141 baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05. Conclusion Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. Trial Registration ACTRN12608000638336

Fast static field CIPT mapping of unpatterned MRAM film stacks

DEFF Research Database (Denmark)

Kjær, Daniel; Hansen, Ole; Henrichsen, Henrik Hartmann

2015-01-01

Current In-Plane Tunneling (CIPT) method measures both RA and TMR, but the usefulness for uniformity mapping, e.g. for tool optimization, is limited by excessive measurement time. Thus, we develop and demonstrate a fast complementary static magnetic field method focused only on measurement of RA. We...... compare the static field method to the standard CIPT method and find perfect agreement between the extracted RA values and measurement repeatability while the static field method is several times faster. The static field CIPT method is demonstrated for 200 mm wafer mapping showing radial as well...

From Flow Logic to static type systems for coordination languages

DEFF Research Database (Denmark)

De Nicola, Rocco; Gorla, Daniele; Hansen, Rene Rydhof

2010-01-01

checks; therefore, the correctness properties cannot be statically enforced. By contrast, static analysis approaches based on Flow Logic usually guarantee properties statically. In this paper, we show how the insights from the Flow Logic approach can be used to construct a type system for statically......Coordination languages are often used to describe open-ended systems. This makes it challenging to develop tools for guaranteeing the security of the coordinated systems and the correctness of their interaction. Successful approaches to this problem have been based on type systems with dynamic...

From Flow Logic to Static Type Systems in Coordination Languages

DEFF Research Database (Denmark)

De Nicola, Rocco; Gorla, Daniele; Hansen, René Rydhof

2008-01-01

; therefore, the correctness properties cannot be statically enforced. By contrast, static analysis approaches based on Flow Logic usually guarantee properties statically. In this paper we show how to combine these two approaches to obtain a static type system for describing secure access to tuple spaces......Coordination languages are often used to describe open ended systems. This makes it challenging to develop tools for guaranteeing security of the coordinated systems and correctness of their interaction. Successful approaches to this problem have been based on type systems with dynamic checks...

Miniature Flow-Direction/Pitot-Static Pressure Probes

Science.gov (United States)

Ashby, George C., Jr.; Coombs, David S.; Eves, John W.; Price, Howard E.; Vasquez, Peter

1989-01-01

Precision flow-direction/pitot-static pressure probes, ranging from 0.035 to 0.090 inch (0.89 to 2.29 mm) in outside diameter, successfully fabricated and calibrated for use in Langley 20-inch Mach 6 Tunnel. Probes simultaneously measure flow direction and static and pitot pressures in flow fields about configurations in hypersonic flow at temperatures up to 500 degree F (260 degree C).

Single-dose-response curves of murine gastrointestinal crypt stem cells

International Nuclear Information System (INIS)

Masuda, K.; Withers, H.R.; Mason, K.A.; Chen, K.Y.

1977-01-01

Dose-response curves for the reproductive capacity of crypt stem cells of murine colonic, jejunal, and gastric mucosae exposed in situ to multifractionated gamma ray exposures were analyzed and single-dose-survival curves of these cells were constructed. The following conclusions were drawn: (1) The single-dose-response curves bend downward over a dose range of approximately 200 to 1500 rad; (2) cell death seems to be due to nonrepairable damage at doses less than 250 rad for colon, and 220 rad for jejunum; (3) there are 21, 110, and 140 stem cells per crypt of gastric, colonic, and jejunal mucosa, respectively; and (4) jejunal stem cells are the most radiosensitive and gastric mucosal stem cells are the most resistant

Circulating progenitor and angiogenic cell frequencies are abnormally static over pregnancy in women with preconception diabetes: A pilot study.

Science.gov (United States)

Lima, Patricia D A; Chen, Zhilin; Tayab, Aysha; Murphy, Malia S Q; Pudwell, Jessica; Smith, Graeme N; Croy, B Anne

2017-01-01

Type 1 and 2 diabetes decrease the frequencies and functional capacities of circulating angiogenic cells (CAC). Diabetes also elevates gestational complications. These observations may be interrelated. We undertook pilot studies to address the hypothesis that preconception diabetes deviates known gestational increases in CACs. Cross-sectional study of type 1 diabetic, type 2 diabetic and normoglycemic pregnant women was conducted at 1st, 2nd, and 3rd trimester and compared to a 6mo postpartum surrogate baseline. Circulating progenitor cells (CPC; CD34+CD45dimSSlow) and CACs (CD34+CD45dimSSlow expressing CD133 without or with KDR) were quantified by flow cytometry and by colony assay (CFU-Hill). In pregnant normoglycemic women, CD34+CD45dimSSlow cell frequency was greater in 1st and 3rd trimester than postpartum but frequency of these cells was static over type 1 or 2 diabetic pregnancies. Type 1 and type 2 diabetic women showed CACs variance versus normal controls. Type 1 diabetic women had more total CD34+KDR+ CACs in 1st trimester and a higher ratio of CD133+KDR+ to total CD133+ cells in 1st and 2nd trimesters than control women, demonstrating an unbalance in CD133+KDR+ CACs. Type 2 diabetic women had more CD133+KDR+ CACs in 1st trimester and fewer CD133+KDR- CACs at mid-late pregnancy than normal pregnant women. Thus, pregnancy stage-specific physiological fluctuation in CPCs (CD34+) and CACs (CD133+KDR+ and CD133+KDR-) did not occur in type 1 and type 2 diabetic women. Early outgrowth colonies were stable across normal and diabetic pregnancies. Therefore, preconception diabetes blocks the normal dynamic pattern of CAC frequencies across gestation but does not alter colony growth. The differences between diabetic and typical women were seen at specific gestational stages that may be critical for initiation of the uterine vascular pathologies characterizing diabetic gestations.

Circulating progenitor and angiogenic cell frequencies are abnormally static over pregnancy in women with preconception diabetes: A pilot study.

Directory of Open Access Journals (Sweden)

Patricia D A Lima

Full Text Available Type 1 and 2 diabetes decrease the frequencies and functional capacities of circulating angiogenic cells (CAC. Diabetes also elevates gestational complications. These observations may be interrelated. We undertook pilot studies to address the hypothesis that preconception diabetes deviates known gestational increases in CACs. Cross-sectional study of type 1 diabetic, type 2 diabetic and normoglycemic pregnant women was conducted at 1st, 2nd, and 3rd trimester and compared to a 6mo postpartum surrogate baseline. Circulating progenitor cells (CPC; CD34+CD45dimSSlow and CACs (CD34+CD45dimSSlow expressing CD133 without or with KDR were quantified by flow cytometry and by colony assay (CFU-Hill. In pregnant normoglycemic women, CD34+CD45dimSSlow cell frequency was greater in 1st and 3rd trimester than postpartum but frequency of these cells was static over type 1 or 2 diabetic pregnancies. Type 1 and type 2 diabetic women showed CACs variance versus normal controls. Type 1 diabetic women had more total CD34+KDR+ CACs in 1st trimester and a higher ratio of CD133+KDR+ to total CD133+ cells in 1st and 2nd trimesters than control women, demonstrating an unbalance in CD133+KDR+ CACs. Type 2 diabetic women had more CD133+KDR+ CACs in 1st trimester and fewer CD133+KDR- CACs at mid-late pregnancy than normal pregnant women. Thus, pregnancy stage-specific physiological fluctuation in CPCs (CD34+ and CACs (CD133+KDR+ and CD133+KDR- did not occur in type 1 and type 2 diabetic women. Early outgrowth colonies were stable across normal and diabetic pregnancies. Therefore, preconception diabetes blocks the normal dynamic pattern of CAC frequencies across gestation but does not alter colony growth. The differences between diabetic and typical women were seen at specific gestational stages that may be critical for initiation of the uterine vascular pathologies characterizing diabetic gestations.

Water cooled static pressure probe

Science.gov (United States)

Lagen, Nicholas T. (Inventor); Eves, John W. (Inventor); Reece, Garland D. (Inventor); Geissinger, Steve L. (Inventor)

1991-01-01

An improved static pressure probe containing a water cooling mechanism is disclosed. This probe has a hollow interior containing a central coolant tube and multiple individual pressure measurement tubes connected to holes placed on the exterior. Coolant from the central tube symmetrically immerses the interior of the probe, allowing it to sustain high temperature (in the region of 2500 F) supersonic jet flow indefinitely, while still recording accurate pressure data. The coolant exits the probe body by way of a reservoir attached to the aft of the probe. The pressure measurement tubes are joined to a single, larger manifold in the reservoir. This manifold is attached to a pressure transducer that records the average static pressure.

ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

International Nuclear Information System (INIS)

Doi, Keiko; Fujimoto, Takahiro; Okamura, Tadashi; Ogawa, Masahiro; Tanaka, Yoko; Mototani, Yasumasa; Goto, Motohito; Ota, Takeharu; Matsuzaki, Hiroshi; Kuroki, Masahide; Tsunoda, Toshiyuki; Sasazuki, Takehiko; Shirasawa, Senji

2012-01-01

Highlights: ► We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. ► Zfat-deficiency leads to reduction in the number of the peripheral T cells. ► Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. ► Decreased expression of IL-7Rα, IL-2Rα and IL-2 in Zfat-deficient peripheral T cells. ► Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7Rα and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2Rα expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

Hemodynamic Changes After Static and Dynamic Exercises and Treadmill Stress Test; Different Patterns in Patients with Primary Benign Exertional Headache?

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Mohsen Rostami

2012-06-01

Full Text Available The pathophysiology of primary benign exertional headache (EH is not still clearly defined. Some researchers have suggested an impaired vascular response as the etiology of this disorder. In this study we investigated whether there are any differences in blood pressure (BP and heart rate (HR of the subjects in course of the static and dynamic exercises and the treadmill stress test between those with and without EH. From university students, 22 patients with EH (mean age: 19.8 ± 2.10, Female to Male: 7:15 and 20 normal subjects (mean age: 19.3 ± 1.97, Female: Male: 8:12 were recruited. All the subjects performed the static and dynamic exercises at 30 and 20 percent of the maximal voluntary contraction (MVC and Bruce treadmill stress test according to the standard protocols. HR and BP of all the cases at the baseline and during and immediately after each test were measured. No significant difference was found between the mean rise of HR, systolic and diastolic BP of the subjects with and without EH in static and dynamic exercises and also treadmill stress test. It seems that between those with and without EH, there is no significant difference in rise of HR and BP response to static and dynamic exercises and treadmill stress test. Further studies are required to find the pathophysiology and risk factors of EH.

Hemodynamic changes after static and dynamic exercises and treadmill stress test; different patterns in patients with primary benign exertional headache?

Science.gov (United States)

Kordi, Ramin; Mazaheri, Reza; Rostami, Mohsen; Mansournia, Mohammad Ali

2012-01-01

The pathophysiology of primary benign exertional headache (EH) is not still clearly defined. Some researchers have suggested an impaired vascular response as the etiology of this disorder. In this study we investigated whether there are any differences in blood pressure (BP) and heart rate (HR) of the subjects in course of the static and dynamic exercises and the treadmill stress test between those with and without EH. From university students, 22 patients with EH (mean age: 19.8 ± 2.10, Female to Male: 7:15) and 20 normal subjects (mean age: 19.3 ± 1.97, Female: Male: 8:12) were recruited. All the subjects performed the static and dynamic exercises at 30 and 20 percent of the maximal voluntary contraction (MVC) and Bruce treadmill stress test according to the standard protocols. HR and BP of all the cases at the baseline and during and immediately after each test were measured. No significant difference was found between the mean rise of HR, systolic and diastolic BP of the subjects with and without EH in static and dynamic exercises and also treadmill stress test. It seems that between those with and without EH, there is no significant difference in rise of HR and BP response to static and dynamic exercises and treadmill stress test. Further studies are required to find the pathophysiology and risk factors of EH.

A time correlation function theory describing static field enhanced third order optical effects at interfaces.

Science.gov (United States)

Neipert, Christine; Space, Brian

2006-12-14

Sum vibrational frequency spectroscopy, a second order optical process, is interface specific in the dipole approximation. At charged interfaces, there exists a static field, and as a direct consequence, the experimentally detected signal is a combination of enhanced second and static field induced third order contributions. There is significant evidence in the literature of the importance/relative magnitude of this third order contribution, but no previous molecularly detailed approach existed to separately calculate the second and third order contributions. Thus, for the first time, a molecularly detailed time correlation function theory is derived here that allows for the second and third order contributions to sum frequency vibrational spectra to be individually determined. Further, a practical, molecular dynamics based, implementation procedure for the derived correlation functions that describe the third order phenomenon is also presented. This approach includes a novel generalization of point atomic polarizability models to calculate the hyperpolarizability of a molecular system. The full system hyperpolarizability appears in the time correlation functions responsible for third order contributions in the presence of a static field.

Non-static vacuum strings: exterior and interior solutions

International Nuclear Information System (INIS)

Stein-Schabes, J.A.

1986-01-01

New non-static cylindrically symmetric solutions of Einsteins's equations are presented. Some of these solutions represent string-like objects. An exterior vacuum solution is matched to a non-vacuum interior solution for different forms of the energy-momentum tensor. They generalize the standard static string. 12 refs

Induction of non-responsiveness in human allergen-specific type 2 T helper cells.

Science.gov (United States)

Yssel, H; Fasler, S; Lamb, J; de Vries, J E

1994-12-01

Activation of allergen-reactive human T helper (Th)2 cells in the absence of professional antigen-presenting cells, induces non-responsiveness or anergy in these cells in vitro. This induction of anergy is accompanied by phenotypic modulation and altered cytokine production. Furthermore, peptide-treated Th2 cells fail to provide B-cell help for IgE synthesis. Recent studies indicate that impaired signal transduction via the T-cell receptor may account for the lack of responsiveness to antigenic stimulation. Here, we review present knowledge on the cell biology of non-responsive or anergic Th2 cells.

Influence of cell cycle on responses of MCF-7 cells to benzo[a]pyrene

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Giddings Ian

2011-06-01

Full Text Available Abstract Background Benzo[a]pyrene (BaP is a widespread environmental genotoxic carcinogen that damages DNA by forming adducts. This damage along with activation of the aryl hydrocarbon receptor (AHR induces complex transcriptional responses in cells. To investigate whether human cells are more susceptible to BaP in a particular phase of the cell cycle, synchronised breast carcinoma MCF-7 cells were exposed to BaP. Cell cycle progression was analysed by flow cytometry, DNA adduct formation was assessed by 32P-postlabeling analysis, microarrays of 44K human genome-wide oligos and RT-PCR were used to detect gene expression (mRNA changes and Western blotting was performed to determine the expression of some proteins, including cytochrome P450 (CYP 1A1 and CYP1B1, which are involved in BaP metabolism. Results Following BaP exposure, cells evaded G1 arrest and accumulated in S-phase. Higher levels of DNA damage occurred in S- and G2/M- compared with G0/G1-enriched cultures. Genes that were found to have altered expression included those involved in xenobiotic metabolism, apoptosis, cell cycle regulation and DNA repair. Gene ontology and pathway analysis showed the involvement of various signalling pathways in response to BaP exposure, such as the Catenin/Wnt pathway in G1, the ERK pathway in G1 and S, the Nrf2 pathway in S and G2/M and the Akt pathway in G2/M. An important finding was that higher levels of DNA damage in S- and G2/M-enriched cultures correlated with higher levels of CYP1A1 and CYP1B1 mRNA and proteins. Moreover, exposure of synchronised MCF-7 cells to BaP-7,8-diol-9,10-epoxide (BPDE, the ultimate carcinogenic metabolite of BaP, did not result in significant changes in DNA adduct levels at different phases of the cell cycle. Conclusions This study characterised the complex gene response to BaP in MCF-7 cells and revealed a strong correlation between the varying efficiency of BaP metabolism and DNA damage in different phases of the cell

Unconventional Pro-inflammatory CD4+ T Cell Response in B Cell-Deficient Mice Infected with Trypanosoma cruzi

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Melisa Gorosito Serrán

2017-11-01

Full Text Available Chagas disease, caused by the parasite Trypanosoma cruzi, is endemic in Latin America but has become a global public health concern by migration of infected people. It has been reported that parasite persistence as well as the intensity of the inflammatory immune response are determinants of the clinical manifestations of the disease. Even though inflammation is indispensable for host defense, when deregulated, it can contribute to tissue injury and organ dysfunction. Here, we report the importance of B cells in conditioning T cell response in T. cruzi infection. Mice deficient in mature B cells (muMT mice infected with T. cruzi exhibited an increase in plasma TNF concentration, TNF-producing CD4+ T cells, and mortality. The increase in TNF-producing CD4+ T cells was accompanied by a reduction in IFNγ+CD4+ T cells and a decrease of the frequency of regulatory Foxp3+, IL-10+, and IL17+CD4+ T cells populations. The CD4+ T cell population activated by T. cruzi infection, in absence of mature B cells, had a high frequency of Ly6C+ cells and showed a lower expression of inhibitory molecules such as CTLA-4, PD-1, and LAG3. CD4+ T cells from infected muMT mice presented a high frequency of CD62LhiCD44− cells, which is commonly associated with a naïve phenotype. Through transfer experiments we demonstrated that CD4+ T cells from infected muMT mice were able to condition the CD4+ T cells response from infected wild-type mice. Interestingly, using Blimp-flox/flox-CD23icre mice we observed that in absence of plasmablast/plasma cell T. cruzi-infected mice exhibited a higher number of TNF-producing CD4+ T cells. Our results showed that the absence of B cells during T. cruzi infection affected the T cell response at different levels and generated a favorable scenario for unconventional activation of CD4+ T cell leading to an uncontrolled effector response and inflammation. The product of B cell differentiation, the plasmablast/plasma cells, could be able

Passive elimination of static electricity in oil industry

Directory of Open Access Journals (Sweden)

Gaćanović Mićo

2014-01-01

Full Text Available This study explains the existing and real conditions of a possible passive elimination of static electricity when loading oil and oil derivatives. We are considering the formation and survival of gas bubbles both in the volume of oil in its depth, but also at the surface of oil and oil derivatives of the partly filled reservoir, and formation of both volume and surface electric charge in oil and oil derivatives. The study presents the research of formation and survival of static electricity in both reservoirs and tank trucks of different geometric shapes partly filled with oil and oil derivatives. We are proposing a new original possibility of passive elimination of static electricity when loading oil and oil derivatives in reservoirs and tank trucks. The proposed passive device for elimination of static electricity is protected at the international level in the domain of intellectual property (with a patent, model and distinctive mark.

A Static Burst Test for Composite Flywheel Rotors

Science.gov (United States)

Hartl, Stefan; Schulz, Alexander; Sima, Harald; Koch, Thomas; Kaltenbacher, Manfred

2016-06-01

High efficient and safe flywheels are an interesting technology for decentralized energy storage. To ensure all safety aspects, a static test method for a controlled initiation of a burst event for composite flywheel rotors is presented with nearly the same stress distribution as in the dynamic case, rotating with maximum speed. In addition to failure prediction using different maximum stress criteria and a safety factor, a set of tensile and compressive tests is carried out to identify the parameters of the used carbon fiber reinforced plastics (CFRP) material. The static finite element (FE) simulation results of the flywheel static burst test (FSBT) compare well to the quasistatic FE-simulation results of the flywheel rotor using inertia loads. Furthermore, it is demonstrated that the presented method is a very good controllable and observable possibility to test a high speed flywheel energy storage system (FESS) rotor in a static way. Thereby, a much more expensive and dangerous dynamic spin up test with possible uncertainties can be substituted.

X-ray-induced bystander response reduce spontaneous mutations in V79 cells

International Nuclear Information System (INIS)

Maeda, Munetoshi; Kobayashi, Katsumi; Matsumoto, Hideki; Usami, Noriko; Tomiya, Masanori

2013-01-01

The potential for carcinogenic risks is increased by radiation-induced bystander responses; these responses are the biological effects in unirradiated cells that receive signals from the neighboring irradiated cells. Bystander responses have attracted attention in modern radiobiology because they are characterized by non-linear responses to low-dose radiation. We used a synchrotron X-ray microbeam irradiation system developed at the Photon Factory, High Energy Accelerator Research Organization, KEK, and showed that nitric oxide (NO)-mediated bystander cell death increased biphasically in a dose-dependent manner. Here, we irradiated five cell nuclei using 10 × 10 µm 2 5.35 keV X-ray beams and then measured the mutation frequency at the hypoxanthine-guanosine phosphoribosyl transferase (HPRT) locus in bystander cells. The mutation frequency with the null radiation dose was 2.6 × 10 -5 (background level), and the frequency decreased to 5.3 × 10 -6 with a dose of approximately 1 Gy (absorbed dose in the nucleus of irradiated cells). At high doses, the mutation frequency returned to the background level. A similar biphasic dose-response effect was observed for bystander cell death. Furthermore, we found that incubation with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a specific scavenger of NO, suppressed not only the biphasic increase in bystander cell death but also the biphasic reduction in mutation frequency of bystander cells. These results indicate that the increase in bystander cell death involves mechanisms that suppress mutagenesis. This study has thus shown that radiation-induced bystander responses could affect processes that protect the cell against naturally occurring alterations such as mutations. (author)

Effects of a low-voltage static electric field on energy metabolism in astrocytes.

Science.gov (United States)

Huang, R; Peng, L; Hertz, L

1997-01-01

Mouse astrocytes (glial cells) in primary cultures were exposed to a low-voltage static DC electric field with no current flow and thus with no generation of magnetic fields. The electric field altered the rate of glycolysis, measured by 2-deoxyglucose accumulation. The magnitude and direction of this effect depended on the polarization of the field and the applied voltage. The maximum effect was an increase of approximately 30%, which occurred with field across the cells at an intensity that can be calculated to be 0.3 mV/cm or less. Reversal of the polarization converted the stimulation to a small but statistically significant inhibition.

Extending and Enhancing SAS (Static Analysis Suite)

CERN Document Server

Ho, David

2016-01-01

The Static Analysis Suite (SAS) is an open-source software package used to perform static analysis on C and C++ code, helping to ensure safety, readability and maintainability. In this Summer Student project, SAS was enhanced to improve ease of use and user customisation. A straightforward method of integrating static analysis into a project at compilation time was provided using the automated build tool CMake. The process of adding checkers to the suite was streamlined and simplied by developing an automatic code generator. To make SAS more suitable for continuous integration, a reporting mechanism summarising results was added. This suitability has been demonstrated by inclusion of SAS in the Future Circular Collider Software nightly build system. Scalability of the improved package was demonstrated by using the tool to analyse the ROOT code base.

B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction

OpenAIRE

Shin, Jung Hoon; Park, Se-Ho

2013-01-01

CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although ?-galactosylceramide (?-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-? by NKT cells, concomitant with a d...

Einstein's conversion from his static to an expanding universe

Science.gov (United States)

Nussbaumer, Harry

2014-02-01

In 1917 Einstein initiated modern cosmology by postulating, based on general relativity, a homogenous, static, spatially curved universe. To counteract gravitational contraction he introduced the cosmological constant. In 1922 Alexander Friedman showed that Albert Einstein's fundamental equations also allow dynamical worlds, and in 1927 Georges Lemaître, backed by observational evidence, concluded that our universe was expanding. Einstein impetuously rejected Friedman's as well as Lemaître's findings. However, in 1931 he retracted his former static model in favour of a dynamic solution. This investigation follows Einstein on his hesitating path from a static to the expanding universe. Contrary to an often advocated belief the primary motive for his switch was not observational evidence, but the realisation that his static model was unstable.

Static compensators (STATCOMs) in power systems

CERN Document Server

Shahnia, Farhad; Ghosh, Arindam

2014-01-01

A static compensator (STATCOM), also known as static synchronous compensator, is a member of the flexible alternating current transmission system (FACTS) devices. It is a power-electronics based regulating device which is composed of a voltage source converter (VSC) and is shunt-connected to alternating current electricity transmission and distribution networks. The voltage source is created from a DC capacitor and the STATCOM can exchange reactive power with the network. It can also supply some active power to the network, if a DC source of power is connected across the capacitor. A STATCOM

Leptin Suppresses Mouse Taste Cell Responses to Sweet Compounds.

Science.gov (United States)

Yoshida, Ryusuke; Noguchi, Kenshi; Shigemura, Noriatsu; Jyotaki, Masafumi; Takahashi, Ichiro; Margolskee, Robert F; Ninomiya, Yuzo

2015-11-01

Leptin is known to selectively suppress neural and behavioral responses to sweet-tasting compounds. However, the molecular basis for the effect of leptin on sweet taste is not known. Here, we report that leptin suppresses sweet taste via leptin receptors (Ob-Rb) and KATP channels expressed selectively in sweet-sensitive taste cells. Ob-Rb was more often expressed in taste cells that expressed T1R3 (a sweet receptor component) than in those that expressed glutamate-aspartate transporter (a marker for Type I taste cells) or GAD67 (a marker for Type III taste cells). Systemically administered leptin suppressed taste cell responses to sweet but not to bitter or sour compounds. This effect was blocked by a leptin antagonist and was absent in leptin receptor-deficient db/db mice and mice with diet-induced obesity. Blocking the KATP channel subunit sulfonylurea receptor 1, which was frequently coexpressed with Ob-Rb in T1R3-expressing taste cells, eliminated the effect of leptin on sweet taste. In contrast, activating the KATP channel with diazoxide mimicked the sweet-suppressing effect of leptin. These results indicate that leptin acts via Ob-Rb and KATP channels that are present in T1R3-expressing taste cells to selectively suppress their responses to sweet compounds. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Development of a coordinated allo T cell and auto B cell response against autosomal PTK2B after allogeneic hematopoietic stem cell transplantation.

Science.gov (United States)

Kremer, Anita N; van der Griendt, Judith C; van der Meijden, Edith D; Honders, M Willy; Ayoglu, Burcu; Schwenk, Jochen M; Nilsson, Peter; Falkenburg, J H Frederik; Griffioen, Marieke

2014-02-01

It is well known that allo-reactive T cells play a crucial role in graft-versus-leukemia and graft-versus-host disease after allogeneic hematopoietic stem cell transplantation (alloSCT). Allo-reactive CD4(+) T cells can mediate direct cytolysis, but may also stimulate production of IgG antibodies as helper cells. Immune complexes may subsequently be processed and presented by professional antigen presenting cells and stimulate induction of specific CD8(+) T cells. As such, proteins targeted in coordinated T- and B-cell responses may represent a class of immunodominant antigens in clinical responses after alloSCT. We previously identified LB-PTK2B-1T as HLA class II restricted polymorphic antigen in a patient treated with donor lymphocyte infusion for relapsed chronic myeloid leukemia after HLA-matched alloSCT. Since PTK2B has also been described as antibody target, we here investigated whether a coordinated T- and B-cell response against PTK2B was induced. Patient serum before and after alloSCT and donor lymphocyte infusion (DLI) was screened for antibodies, and we indeed observed development of a humoral immune response against PTK2B. Antibodies against PTK2B were only found after DLI and, in contrast to the CD4(+) T cells, recognized a monomorphic region of the protein. To our knowledge, this is the first description of a coordinated allo-reactive CD4(+) T-cell and auto-reactive antibody response against an autosomal antigen.

Molecular mechanisms of radioadaptive responses in human lymphoblastoid cells

International Nuclear Information System (INIS)

Kakimoto, Ayana; Taki, Keiko; Nakajima, Tetsuo

2008-01-01

Radioadaptive response is a biodefensive response observed in a variety of mammalian cells and animals where exposure to low dose radiation induces resistance against the subsequent high dose radiation. Elucidation of its mechanisms is important for risk estimation of low dose radiation because the radioadaptive response implies that low dose radiation affects cells/individuals in a different manner from high dose radiation. In the present study, we explored the molecular mechanisms of the radioadaptive response in human lymphoblastoid cells AHH-1 in terms of mutation at the hypoxanthine phosphoribosyltransferase (HPRT) gene locus. First we observed that preexposure to the priming dose in the range from 0.02 Gy to 0.2 Gy significantly reduced mutation frequency at HPRT gene locus after irradiation with 3 Gy of X rays. As no significant adaptive response was observed with the priming dose of 0.005 Gy, it was indicated that the lower limit of the priming dose to induce radioadaptive response may be between 0.005 Gy and 0.02 Gy. Second, we examined the effect of 3-amino-benzamide (3AB), an inhibitor of poly(ADP-ribose)polymerase1, which has been reported to inhibit the radioadaptive response in terms of chromosome aberration. However we could observe significant radioadaptive responses in terms of mutation even in the presence of 3AB. These findings suggested that molecular mechanisms of the radioadaptive response in terms of mutation may be different from that for radioadaptive responses in terms of chromosomal aberration, although we could not exclude a possibility that the differential effects of 3AB was due to cell type difference. Finally, by performing a comprehensive analysis of alterations in gene expression using high coverage expression profiling (HiCEP), we could identify 17 genes whose expressions were significantly altered 6 h after irradiation with 0.02 Gy. We also found 17 and 20 genes, the expressions of which were different with or without priming

Comparison of pressure perception of static and dynamic two point ...

African Journals Online (AJOL)

... the right and left index finger (p<0.05). Conclusion: Age and gender did not affect the perception of static and dynamic two point discrimination while the limb side (left or right) affected the perception of static and dynamic two point discrimination. The index finger is also more sensitive to moving rather static sensations.

Regimes of wave type patterning driven by refractory actin feedback: transition from static polarization to dynamic wave behaviour

International Nuclear Information System (INIS)

Holmes, W R; Edelstein-Keshet, L; Carlsson, A E

2012-01-01

Patterns of waves, patches, and peaks of actin are observed experimentally in many living cells. Models of this phenomenon have been based on the interplay between filamentous actin (F-actin) and its nucleation promoting factors (NPFs) that activate the Arp2/3 complex. Here we present an alternative biologically-motivated model for F-actin-NPF interaction based on properties of GTPases acting as NPFs. GTPases (such as Cdc42, Rac) are known to promote actin nucleation, and to have active membrane-bound and inactive cytosolic forms. The model is a natural extension of a previous mathematical mini-model of small GTPases that generates static cell polarization. Like other modellers, we assume that F-actin negative feedback shapes the observed patterns by suppressing the trailing edge of NPF-generated wave-fronts, hence localizing the activity spatially. We find that our NPF-actin model generates a rich set of behaviours, spanning a transition from static polarization to single pulses, reflecting waves, wave trains, and oscillations localized at the cell edge. The model is developed with simplicity in mind to investigate the interaction between nucleation promoting factor kinetics and negative feedback. It explains distinct types of pattern initiation mechanisms, and identifies parameter regimes corresponding to distinct behaviours. We show that weak actin feedback yields static patterning, moderate feedback yields dynamical behaviour such as travelling waves, and strong feedback can lead to wave trains or total suppression of patterning. We use a recently introduced nonlinear bifurcation analysis to explore the parameter space of this model and predict its behaviour with simulations validating those results. (paper)

Design and measurement of fully digital ternary content addressable memory using ratioless static random access memory cells and hierarchical-AND matching comparator

Science.gov (United States)

Nishikata, Daisuke; Ali, Mohammad Alimudin Bin Mohd; Hosoda, Kento; Matsumoto, Hiroshi; Nakamura, Kazuyuki

2018-04-01

A 36-bit × 32-entry fully digital ternary content addressable memory (TCAM) using the ratioless static random access memory (RL-SRAM) technology and fully complementary hierarchical-AND matching comparators (HAMCs) was developed. Since its fully complementary and digital operation enables the effect of device variabilities to be avoided, it can operate with a quite low supply voltage. A test chip incorporating a conventional TCAM and a proposed 24-transistor ratioless TCAM (RL-TCAM) cells and HAMCs was developed using a 0.18 µm CMOS process. The minimum operating voltage of 0.25 V of the developed RL-TCAM, which is less than half of that of the conventional TCAM, was measured via the conventional CMOS push–pull output buffers with the level-shifting and flipping technique using optimized pull-up voltage and resistors.

DNA damage responses in human induced pluripotent stem cells and embryonic stem cells.

Directory of Open Access Journals (Sweden)

Olga Momcilovic

2010-10-01

Full Text Available Induced pluripotent stem (iPS cells have the capability to undergo self-renewal and differentiation into all somatic cell types. Since they can be produced through somatic cell reprogramming, which uses a defined set of transcription factors, iPS cells represent important sources of patient-specific cells for clinical applications. However, before these cells can be used in therapeutic designs, it is essential to understand their genetic stability.Here, we describe DNA damage responses in human iPS cells. We observe hypersensitivity to DNA damaging agents resulting in rapid induction of apoptosis after γ-irradiation. Expression of pluripotency factors does not appear to be diminished after irradiation in iPS cells. Following irradiation, iPS cells activate checkpoint signaling, evidenced by phosphorylation of ATM, NBS1, CHEK2, and TP53, localization of ATM to the double strand breaks (DSB, and localization of TP53 to the nucleus of NANOG-positive cells. We demonstrate that iPS cells temporary arrest cell cycle progression in the G(2 phase of the cell cycle, displaying a lack of the G(1/S cell cycle arrest similar to human embryonic stem (ES cells. Furthermore, both cell types remove DSB within six hours of γ-irradiation, form RAD51 foci and exhibit sister chromatid exchanges suggesting homologous recombination repair. Finally, we report elevated expression of genes involved in DNA damage signaling, checkpoint function, and repair of various types of DNA lesions in ES and iPS cells relative to their differentiated counterparts.High degrees of similarity in DNA damage responses between ES and iPS cells were found. Even though reprogramming did not alter checkpoint signaling following DNA damage, dramatic changes in cell cycle structure, including a high percentage of cells in the S phase, increased radiosensitivity and loss of DNA damage-induced G(1/S cell cycle arrest, were observed in stem cells generated by induced pluripotency.

Antigen specific T-cell responses against tumor antigens are controlled by regulatory T cells in patients with prostate cancer.

Science.gov (United States)

Hadaschik, Boris; Su, Yun; Huter, Eva; Ge, Yingzi; Hohenfellner, Markus; Beckhove, Philipp

2012-04-01

Immunotherapy is a promising approach in an effort to control castration resistant prostate cancer. We characterized tumor antigen reactive T cells in patients with prostate cancer and analyzed the suppression of antitumor responses by regulatory T cells. Peripheral blood samples were collected from 57 patients with histologically confirmed prostate cancer, 8 patients with benign prostatic hyperplasia and 16 healthy donors. Peripheral blood mononuclear cells were isolated and antigen specific interferon-γ secretion of isolated T cells was analyzed by enzyme-linked immunospot assay. T cells were functionally characterized and T-cell responses before and after regulatory T-cell depletion were compared. As test tumor antigens, a panel of 11 long synthetic peptides derived from a total of 8 tumor antigens was used, including prostate specific antigen and prostatic acid phosphatase. In patients with prostate cancer we noted a 74.5% effector T-cell response rate compared with only 25% in patients with benign prostatic hyperplasia and 31% in healthy donors. In most patients 2 or 3 tumor antigens were recognized. Comparing various disease stages there was a clear increase in the immune response against prostate specific antigens from intermediate to high risk tumors and castration resistant disease. Regulatory T-cell depletion led to a significant boost in effector T-cell responses against prostate specific antigen and prostatic acid phosphatase. Tumor specific effector T cells were detected in most patients with prostate cancer, especially those with castration resistant prostate cancer. Since effector T-cell responses against prostate specific antigens strongly increased after regulatory T-cell depletion, our results indicate that immunotherapy efficacy could be enhanced by decreasing regulatory T cells. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

LENUS (Irish Health Repository)

O'Sullivan, Kieran

2009-01-01

BACKGROUND: Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. METHODS: A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. RESULTS: Across both groups, there was a significant main effect for time (p < 0.001). PKE ROM significantly increased with warm-up (p < 0.001). From warm-up, PKE ROM further increased with static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p < 0.001) after 15 minutes of rest, but remained significantly greater than at baseline (p < 0.001). Between groups, there was no main effect for group (p = 0.462), with no difference in mean PKE ROM values at any individual stage of the protocol (p > 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). CONCLUSION: Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced

Enhancement of sedimentation and coagulation with static magnetic field

Science.gov (United States)

Zieliński, Marcin; Dębowski, Marcin; Hajduk, Anna; Rusanowska, Paulina

2017-11-01

The static magnetic field can be an alternative method for wastewater treatment. It has been proved that this physical factor, accelerates the biochemical processes, catalyzes advanced oxidation, intensifies anaerobic and aerobic processes or reduces swelling of activated sludge. There are also reports proving the positive impact of the static magnetic field on the coagulation and sedimentation, as well as the conditioning and dewatering of sludge. In order to be applied in larger scale the published results should be verified and confirmed. In the studies, the enhancement of sedimentation by the static magnetic field was observed. The best sedimentation was noted in the experiment, where magnetizers were placed on activated sludge bioreactor and secondary settling tank. No effect of the static magnetic field on coagulation with the utilization of PIX 113 was observed. However, the static magnetic field enhanced coagulation with the utilization of PAX-XL9. The results suggest that increased sedimentation of colloids and activated sludge, can in practice mean a reduction in the size of the necessary equipment for sedimentation with an unchanged efficiency of the process.

IL-10 polymorphism and cell-mediated immune response to Chlamydia trachomatis

DEFF Research Database (Denmark)

Öhman, H.; Tiitinen, A; Halttunen, M.

2006-01-01

background. To study a relationship between interleukin-10 (IL-10) promoter -1082 polymorphism and cell-mediated immune response during C trachomatis infection in vitro, lymphocyte proliferation and cytokine (IL-10, IFN-gamma, TNF-alpha, IL-2, IL-4 and IL-5) secretion were analysed in subjects with different...... IL-10 genotypes. Enhanced IL-10 secretion and reduced antigen-specific lymphocyte proliferative and IFN-gamma responses were found in subjects with IL-10 -1082 GG genotype when compared to those with -1082 AA genotype. CD14+ monocytes were main source of IL-10 indicating that these cells...... are important regulators of the antigen-specific cell-mediated responses during active C trachomatis infection. We conclude that impaired cell-mediated response to C trachomatis is associated with IL-10 genotype in subjects with high IL-10 producing capacity. A comparison of immune markers between subjects...

Hydrogen generation through static-feed water electrolysis

Science.gov (United States)

Jensen, F. C.; Schubert, F. H.

1975-01-01

A static-feed water electrolysis system (SFWES), developed under NASA sponsorship, is presented for potential applicability to terrestrial hydrogen production. The SFWES concept uses (1) an alkaline electrolyte to minimize power requirements and materials-compatibility problems, (2) a method where the electrolyte is retained in a thin porous matrix eliminating bulk electrolyte, and (3) a static water-feed mechanism to prevent electrode and electrolyte contamination and to promote system simplicity.

Frequency response of electrochemical cells

Science.gov (United States)

Thomas, Daniel L.

1990-01-01

The main objective was to examine the feasibility of using frequency response techniques (1) as a tool in destructive physical analysis of batteries, particularly for estimating electrode structural parameters such as specific area, porosity, and tortuosity and (2) as a non-destructive testing technique for obtaining information such as state of charge and acceptability for space flight. The phenomena that contribute to the frequency response of an electrode include: (1) double layer capacitance; (2) Faradaic reaction resistance; (3) mass transfer of Warburg impedance; and (4) ohmic solution resistance. Nickel cadmium cells were investigated in solutions of KOH. A significant amount of data was acquired. Quantitative data analysis, using the developed software, is planned for the future.

Endogenous Tim-1 (Kim-1) promotes T-cell responses and cell-mediated injury in experimental crescentic glomerulonephritis.

Science.gov (United States)

Nozaki, Yuji; Nikolic-Paterson, David J; Snelgrove, Sarah L; Akiba, Hisaya; Yagita, Hideo; Holdsworth, Stephen R; Kitching, A Richard

2012-05-01

The T-cell immunoglobulin mucin 1 (Tim-1) modulates CD4(+) T-cell responses and is also expressed by damaged proximal tubules in the kidney where it is known as kidney injury molecule-1 (Kim-1). We sought to define the role of endogenous Tim-1 in experimental T-cell-mediated glomerulonephritis induced by sheep anti-mouse glomerular basement membrane globulin acting as a planted foreign antigen. Tim-1 is expressed by infiltrating activated CD4(+) cells in this model, and we studied the effects of an inhibitory anti-Tim-1 antibody (RMT1-10) on immune responses and glomerular disease. Crescentic glomerulonephritis, proliferative injury, and leukocyte accumulation were attenuated following treatment with anti-Tim-1 antibodies, but interstitial foxp3(+) cell accumulation and interleukin-10 mRNA were increased. T-cell proliferation and apoptosis decreased in the immune system along with a selective reduction in Th1 and Th17 cellular responses both in the immune system and within the kidney. The urinary excretion and renal expression of Kim-1 was reduced by anti-Tim-1 antibodies reflecting diminished interstitial injury. The effects of anti-Tim-1 antibodies were not apparent in the early phase of renal injury, when the immune response to sheep globulin was developing. Thus, endogenous Tim-1 promotes Th1 and Th17 nephritogenic immune responses and its neutralization reduces renal injury while limiting inflammation in cell-mediated glomerulonephritis.

Effects of blood products on inflammatory response in endothelial cells in vitro.

Directory of Open Access Journals (Sweden)

Martin Urner

Full Text Available BACKGROUND: Transfusing blood products may induce inflammatory reactions within the vascular compartment potentially leading to a systemic inflammatory response. Experiments were designed to assess the inflammatory potential of different blood products in an endothelial cell-based in vitro model and to compare baseline levels of potentially activating substances in transfusion products. METHODS: The inflammatory response from pre-activated (endotoxin-stimulated and non-activated endothelial cells as well as neutrophil endothelial transmigration in response to packed red blood cells (PRBC, platelet concentrates (PC and fresh frozen plasma (FFP was determined. Baseline inflammatory mediator and lipid concentrations in blood products were evaluated. RESULTS: Following incubation with all blood products, an increased inflammatory mediator release from endothelial cells was observed. Platelet concentrates, and to a lesser extent also FFP, caused the most pronounced response, which was accentuated in already pre-stimulated endothelial cells. Inflammatory response of endothelial cells as well as blood product-induced migration of neutrophils through the endothelium was in good agreement with the lipid content of the according blood product. CONCLUSION: Within the group of different blood transfusion products both PC and FFP have a high inflammatory potential with regard to activation of endothelial cells. Inflammation upon blood product exposure is strongly accentuated when endothelial cells are pre-injured. High lipid contents in the respective blood products goes along with an accentuated inflammatory reaction from endothelial cells.