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Sample records for mechanical activation assisted

  1. Mechanical Activation-Assisted Reductive Leaching of Cadmium from Zinc Neutral Leaching Residue Using Sulfur Dioxide

    NASA Astrophysics Data System (ADS)

    Zhang, Chun; Min, Xiaobo; Chai, Liyuan; Zhang, Jianqiang; Wang, Mi

    2015-12-01

    In this work, zinc neutral leaching residue was mechanically activated by ball-milling. The subsequent leaching behavior and kinetics of cadmium extraction in a mixed SO2-H2SO4 system were studied. Changes in the crystalline phase, lattice distortion, particle size and morphology, which were induced by mechanical activation, were also investigated. The activated samples showed different physicochemical characteristics, and cadmium extraction was found to be easier than for the un-activated samples. Under the same conditions, mechanical activation contributed to higher cadmium leaching. The cadmium extraction kinetics at 75-95°C was found to fit the shrinking core model. The raw neutral leaching residue, and the samples activated for 60 min and 120 min had a calculated activation energy of 65.02 kJ/mol, 59.45 kJ/mol and 53.46 kJ/mol, respectively. The leaching residue was characterized by ICP, XRD and SEM analysis. According to XRD analysis, the main phases in the residue were lead sulfate (PbSO4), zinc sulfide (ZnS) and cadmium sulfide (CdS).

  2. [Mechanical resuscitation assist devices].

    PubMed

    Fischer, M; Breil, M; Ihli, M; Messelken, M; Rauch, S; Schewe, J-C

    2014-03-01

    In Germany 100,000-160,000 people suffer from out-of-hospital cardiac arrest (OHCA) annually. The incidence of cardiopulmonary resuscitation (CPR) after OHCA varies between emergency ambulance services but is in the range of 30-90 CPR attempts per 100,000 inhabitants per year. Basic life support (BLS) involving chest compressions and ventilation is the key measure of resuscitation. Rapid initiation and quality of BLS are the most critical factors for CPR success. Even healthcare professionals are not always able to ensure the quality of CPR measures. Consequently in recent years mechanical resuscitation devices have been developed to optimize chest compression and the resulting circulation. In this article the mechanical resuscitation devices currently available in Germany are discussed and evaluated scientifically in context with available literature. The ANIMAX CPR device should not be used outside controlled trials as no clinical results have so far been published. The same applies to the new device Corpuls CPR which will be available on the market in early 2014. Based on the current published data a general recommendation for the routine use of LUCAS™ and AutoPulse® CPR cannot be given. The preliminary data of the CIRC trial and the published data of the LINC trial revealed that mechanical CPR is apparently equivalent to good manual CPR. For the final assessment further publications of large randomized studies must be analyzed (e.g. the CIRC and PaRAMeDIC trials). However, case control studies, case series and small studies have already shown that in special situations and in some cases patients will benefit from the automatic mechanical resuscitation devices (LUCAS™, AutoPulse®). This applies especially to emergency services where standard CPR quality is far below average and for patients who require prolonged CPR under difficult circumstances. This might be true in cases of resuscitation due to hypothermia, intoxication and pulmonary embolism as well as

  3. The Resonating Arm Exerciser: design and pilot testing of a mechanically passive rehabilitation device that mimics robotic active assistance

    PubMed Central

    2013-01-01

    Background Robotic arm therapy devices that incorporate actuated assistance can enhance arm recovery, motivate patients to practice, and allow therapists to deliver semi-autonomous training. However, because such devices are often complex and actively apply forces, they have not achieved widespread use in rehabilitation clinics or at home. This paper describes the design and pilot testing of a simple, mechanically passive device that provides robot-like assistance for active arm training using the principle of mechanical resonance. Methods The Resonating Arm Exerciser (RAE) consists of a lever that attaches to the push rim of a wheelchair, a forearm support, and an elastic band that stores energy. Patients push and pull on the lever to roll the wheelchair back and forth by about 20 cm around a neutral position. We performed two separate pilot studies of the device. In the first, we tested whether the predicted resonant properties of RAE amplified a user’s arm mobility by comparing his or her active range of motion (AROM) in the device achieved during a single, sustained push and pull to the AROM achieved during rocking. In a second pilot study designed to test the therapeutic potential of the device, eight participants with chronic stroke (35 ± 24 months since injury) and a mean, stable, initial upper extremity Fugl-Meyer (FM) score of 17 ± 8 / 66 exercised with RAE for eight 45 minute sessions over three weeks. The primary outcome measure was the average AROM measured with a tilt sensor during a one minute test, and the secondary outcome measures were the FM score and the visual analog scale for arm pain. Results In the first pilot study, we found people with a severe motor impairment after stroke intuitively found the resonant frequency of the chair, and the mechanical resonance of RAE amplified their arm AROM by a factor of about 2. In the second pilot study, AROM increased by 66% ± 20% (p = 0.003). The mean FM score increase was 8.5 ± 4 pts (p = 0

  4. A Substrate-Assisted Mechanism of Nucleophile Activation in a Ser-His-Asp Containing C-C Bond Hydrolase

    SciTech Connect

    Ruzzini, Antonio C.; Bhowmik, Shiva; Ghosh, Subhangi; Yam, Katherine C.; Bolin, Jeffrey T.; Eltis, Lindsay D.

    2013-11-12

    The meta-cleavage product (MCP) hydrolases utilize a Ser–His–Asp triad to hydrolyze a carbon–carbon bond. Hydrolysis of the MCP substrate has been proposed to proceed via an enol-to-keto tautomerization followed by a nucleophilic mechanism of catalysis. Ketonization involves an intermediate, ESred, which possesses a remarkable bathochromically shifted absorption spectrum. We investigated the catalytic mechanism of the MCP hydrolases using DxnB2 from Sphingomonas wittichii RW1. Pre-steady-state kinetic and LC ESI/MS evaluation of the DxnB2-mediated hydrolysis of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid to 2-hydroxy-2,4-pentadienoic acid and benzoate support a nucleophilic mechanism catalysis. In DxnB2, the rate of ESred decay and product formation showed a solvent kinetic isotope effect of 2.5, indicating that a proton transfer reaction, assigned here to substrate ketonization, limits the rate of acylation. For a series of substituted MCPs, this rate was linearly dependent on MCP pKa2nuc ~ 1). Structural characterization of DxnB2 S105A:MCP complexes revealed that the catalytic histidine is displaced upon substrate-binding. The results provide evidence for enzyme-catalyzed ketonization in which the catalytic His–Asp pair does not play an essential role. The data further suggest that ESred represents a dianionic intermediate that acts as a general base to activate the serine nucleophile. This substrate-assisted mechanism of nucleophilic catalysis distinguishes MCP hydrolases from other serine hydrolases.

  5. Chemically assisted mechanical refrigeration process

    DOEpatents

    Vobach, Arnold R.

    1987-01-01

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing he evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  6. Chemically assisted mechanical refrigeration process

    DOEpatents

    Vobach, Arnold R.

    1987-01-01

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  7. Chemically assisted mechanical refrigeration process

    DOEpatents

    Vobach, A.R.

    1987-06-23

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

  8. Chemically assisted mechanical refrigeration process

    DOEpatents

    Vobach, A.R.

    1987-11-24

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

  9. Microwave-assisted synthesis, anticonvulsant activity and quantum mechanical modelling of N-(4-bromo-3-methylphenyl) semicarbazones*

    PubMed Central

    Shalini, Mehta; Yogeeswari, Perumal; Sriram, Dharmarajan; Induja, Sridharan

    2007-01-01

    Objective: To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods: A series of twenty-six compounds of N4-(4-bromo-3-methylphenyl) semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine (scSTY) and subcutaneous picrotoxin (scPIC) seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS (central nervous system) depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results: Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electroshock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels was, the greater was the activity profile. Conclusion: The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds. PMID:17173362

  10. Assessing the Relative Contributions of Active Ankle and Knee Assistance to the Walking Mechanics of Transfemoral Amputees Using a Powered Prosthesis

    PubMed Central

    Simon, Ann M.; Hargrove, Levi J.

    2016-01-01

    Powered knee-ankle prostheses are capable of providing net-positive mechanical energy to amputees. Yet, there are limitless ways to deliver this energy throughout the gait cycle. It remains largely unknown how different combinations of active knee and ankle assistance affect the walking mechanics of transfemoral amputees. This study assessed the relative contributions of stance phase knee swing initiation, increasing ankle stiffness and powered plantarflexion as three unilateral transfemoral amputees walked overground at their self-selected walking speed. Five combinations of knee and ankle conditions were evaluated regarding the kinematics and kinetics of the amputated and intact legs using repeated measures analyses of variance. We found eliminating active knee swing initiation or powered plantarflexion was linked to increased compensations of the ipsilateral hip joint during the subsequent swing phase. The elimination of knee swing initiation or powered plantarflexion also led to reduced braking ground reaction forces of the amputated and intact legs, and influenced both sagittal and frontal plane loading of the intact knee joint. Gradually increasing prosthetic ankle stiffness influenced the shape of the prosthetic ankle plantarflexion moment, more closely mirroring the intact ankle moment. Increasing ankle stiffness also corresponded to increased prosthetic ankle power generation (despite a similar maximum stiffness value across conditions) and increased braking ground reaction forces of the amputated leg. These findings further our understanding of how to deliver assistance with powered knee-ankle prostheses and the compensations that occur when specific aspects of assistance are added/removed. PMID:26807889

  11. Assessing the Relative Contributions of Active Ankle and Knee Assistance to the Walking Mechanics of Transfemoral Amputees Using a Powered Prosthesis.

    PubMed

    Ingraham, Kimberly A; Fey, Nicholas P; Simon, Ann M; Hargrove, Levi J

    2016-01-01

    Powered knee-ankle prostheses are capable of providing net-positive mechanical energy to amputees. Yet, there are limitless ways to deliver this energy throughout the gait cycle. It remains largely unknown how different combinations of active knee and ankle assistance affect the walking mechanics of transfemoral amputees. This study assessed the relative contributions of stance phase knee swing initiation, increasing ankle stiffness and powered plantarflexion as three unilateral transfemoral amputees walked overground at their self-selected walking speed. Five combinations of knee and ankle conditions were evaluated regarding the kinematics and kinetics of the amputated and intact legs using repeated measures analyses of variance. We found eliminating active knee swing initiation or powered plantarflexion was linked to increased compensations of the ipsilateral hip joint during the subsequent swing phase. The elimination of knee swing initiation or powered plantarflexion also led to reduced braking ground reaction forces of the amputated and intact legs, and influenced both sagittal and frontal plane loading of the intact knee joint. Gradually increasing prosthetic ankle stiffness influenced the shape of the prosthetic ankle plantarflexion moment, more closely mirroring the intact ankle moment. Increasing ankle stiffness also corresponded to increased prosthetic ankle power generation (despite a similar maximum stiffness value across conditions) and increased braking ground reaction forces of the amputated leg. These findings further our understanding of how to deliver assistance with powered knee-ankle prostheses and the compensations that occur when specific aspects of assistance are added/removed. PMID:26807889

  12. Computer Assisted Introduction to Mechanics.

    ERIC Educational Resources Information Center

    Huggins, Elisha R.

    These six chapters provide an introduction to Newtonian mechanics, based on a coordinated use of text material, laboratory work, and the computer. The material is essentially self-contained so that it can serve as a short text on mechanics or as a text supplement in a regular physics course. Chapter 1 is a brief introduction to the computer…

  13. New modes of assisted mechanical ventilation.

    PubMed

    Suarez-Sipmann, F

    2014-05-01

    Recent major advances in mechanical ventilation have resulted in new exciting modes of assisted ventilation. Compared to traditional ventilation modes such as assisted-controlled ventilation or pressure support ventilation, these new modes offer a number of physiological advantages derived from the improved patient control over the ventilator. By implementing advanced closed-loop control systems and using information on lung mechanics, respiratory muscle function and respiratory drive, these modes are specifically designed to improve patient-ventilator synchrony and reduce the work of breathing. Depending on their specific operational characteristics, these modes can assist spontaneous breathing efforts synchronically in time and magnitude, adapt to changing patient demands, implement automated weaning protocols, and introduce a more physiological variability in the breathing pattern. Clinicians have now the possibility to individualize and optimize ventilatory assistance during the complex transition from fully controlled to spontaneous assisted ventilation. The growing evidence of the physiological and clinical benefits of these new modes is favoring their progressive introduction into clinical practice. Future clinical trials should improve our understanding of these modes and help determine whether the claimed benefits result in better outcomes. PMID:24507472

  14. Gravity-Assist Mechanical Simulator for Outreach

    NASA Technical Reports Server (NTRS)

    Doody, David F.; White, Victor E.; Schaff, Mitch D.

    2012-01-01

    There is no convenient way to demonstrate mechanically, as an outreach (or inreach) topic, the angular momentum trade-offs and the conservation of angular momentum associated with gravityassist interplanetary trajectories. The mechanical concepts that underlie gravity assist are often misunderstood or confused, possibly because there is no mechanical analog to it in everyday experience. The Gravity Assist Mech - anical Simulator is a hands-on solution to this longstanding technical communications challenge. Users intuitively grasp the concepts, meeting specific educational objectives. A manually spun wheel with high angular mass and low-friction bearings supplies momentum to an attached spherical neodymium magnet that represents a planet orbiting the Sun. A steel bearing ball following a trajectory across a glass plate above the wheel and magnet undergoes an elastic collision with the revolving magnet, illustrating the gravitational elastic collision between spacecraft and planet on a gravity-assist interplanetary trajectory. Manually supplying the angular momentum for the elastic collision, rather than observing an animation, intuitively conveys the concepts, meeting nine specific educational objectives. Many NASA and JPL interplanetary missions are enabled by the gravity-assist technique.

  15. Spatially Assisted Schwinger Mechanism and Magnetic Catalysis.

    PubMed

    Copinger, Patrick; Fukushima, Kenji

    2016-08-19

    Using the worldline formalism we compute an effective action for fermions under a temporally modulated electric field and a spatially modulated magnetic field. It is known that the former leads to an enhanced Schwinger mechanism, while we find that the latter can also result in enhanced particle production and even cause a reorganization of the vacuum to acquire a larger dynamical mass in equilibrium which spatially assists the magnetic catalysis. PMID:27588845

  16. A MECHANISM FOR ASH ASSISTED SLUDGE DEWATERING

    EPA Science Inventory

    The ability of various additives to improve the dewaterability of activated sludge was determined and the surface properties of additives characterized in order to arrive at a mechanism for ash conditioning of activated sludge. The primary additives investigated were fly ash and ...

  17. Computer Assisted Mechanical Axis and Kinematic TKA

    PubMed Central

    McEwen, Peter; Mahoharan, Varaguna

    2016-01-01

    Introduction: Total knee arthroplasty (TKA) has traditionally been and largely continues to be aligned mechanically, that being with a neutral coronal plane mechanical tibiofemoral axis and a joint line orientated at 900 to this axis. Femoral component rotation is set by gap balancing or by externally rotating 30 from any of a number femoral reference lines. This produces a rectangular flexion gap and relaxes patellar tracking. Kinematic alignment (KA) is an alternative technique that aims to restore premorbid alignment, joint orientation and ligament tension. The basic premise for this technique is based on evidence that the medial and lateral femoral condyles consistently equate to cylinders of equal or near equal size and that therefore with a fixed radius, cruciate retaining implant, matched distal femoral, posterior femoral and proximal tibial resections, accounting for bone and cartilage already lost will reproduce the premorbid joint line and restore native premorbid kinematics. Femoral rotation is therefore referenced off the prearthritic posterior condylar axis (PCA) that is on average internally rotated to the AP axis. Kinematic alignment therefore has the potential to challenge patellar tracking, increase patellar load and potentially increase patellar complications. Method: Case control study – level of evidence III-2. Between November 2012 and June 2013 the senior author completed 104 consecutive computer assisted (CAS) kinematically aligned total knee arthroplasties (TKA) with a cruciate retaining, fixed bearing, single radius implant. The results of these surgeries were compared with the results of 91 consecutive CAS mechanically aligned TKA done between November 2011 and October 2012 using the same navigation system and implant Implant sizing and positioning as well as gap measurement and ligament balance was done with computer assistance in all cases. Data was collected prospectively and analysed retrospectively. Results: The Oxford Knee Score

  18. Vibrationally Assisted Electron Transfer Mechanism of Olfaction: Myth or Reality?

    PubMed Central

    Solov’yov, Ilia A.; Chang, Po-Yao; Schulten, Klaus

    2012-01-01

    Smell is a vital sense for animals. The mainstream explanation of smell is based on recognition of the odorant molecules through characteristics of their surface, e.g., shape, but certain experiments suggest that such recognition is complemented by recognition of vibrational modes. According to this suggestion an olfactory receptor is activated by electron transfer assisted through odorant vibrational excitation. The hundreds to thousands of different olfactory receptors in an animal recognize odorants over a discriminant landscape with surface properties and vibrational frequencies as the two major dimensions. In the present paper we introduce the vibrationally assisted mechanism of olfaction and demonstrate for several odorants that, indeed, a strong enhancement of an electron tunneling rate due to odorant vibrations can arise. We discuss in this regard the influence of odorant deuteration and explain, thereby, recent experiments performed on Drosophila melanogaster. Our demonstration is based on known physical properties of biological electron transfer and on ab initio calculations on odorants carried out for the purpose of the present study. We identify a range of physical characteristics which olfactory receptors and odorants must obey for the vibrationally assisted electron transfer mechanism to function. We argue that the stated characteristics are feasible for realistic olfactory receptors, noting, though, that the receptor structure presently is still unknown, but can be studied through homology modeling. PMID:22899100

  19. [Inflammasome: activation mechanisms].

    PubMed

    Suárez, Raibel; Buelvas, Neudo

    2015-03-01

    Inflammation is a rapid biologic response of the immune system in vascular tissues, directed to eliminate stimuli capable of causing damage and begin the process of repair. The macromolecular complexes known as "inflammasomes" are formed by a receptor, either NOD (NLR) or ALR, the receptor absent in melanoma 2 (AIM2). In addition, the inflammasome is formed by the speck-like protein associated to apoptosis (ASC) and procaspase-1, that may be activated by variations in the ionic and intracellular and extracellular ATP concentrations; and the loss of stabilization of the fagolisosomme by internalization of insoluble crystals and redox mechanisms. As a result, there is activation of the molecular platform and the processing of inflammatory prointerleukins to their active forms. There are two modalities of activation of the inflammasome: canonical and non-canonical, both capable of generating effector responses. Recent data associate NLRP 3, IL-1β and IL-18 in the pathogenesis of a variety of diseases, including atherosclerosis, type II diabetes, hyperhomocysteinemia, gout, malaria and hypertension. The inflammasome cascade is emerging as a new chemotherapeutic target in these diseases. In this review we shall discuss the mechanisms of activation and regulation of the inflammasome that stimulate, modulate and resolve inflammation. PMID:25920188

  20. Ventilator-associated lung injury during assisted mechanical ventilation.

    PubMed

    Saddy, Felipe; Sutherasan, Yuda; Rocco, Patricia R M; Pelosi, Paolo

    2014-08-01

    Assisted mechanical ventilation (MV) may be a favorable alternative to controlled MV at the early phase of acute respiratory distress syndrome (ARDS), since it requires less sedation, no paralysis and is associated with less hemodynamic deterioration, better distal organ perfusion, and lung protection, thus reducing the risk of ventilator-associated lung injury (VALI). In the present review, we discuss VALI in relation to assisted MV strategies, such as volume assist-control ventilation, pressure assist-control ventilation, pressure support ventilation (PSV), airway pressure release ventilation (APRV), APRV with PSV, proportional assist ventilation (PAV), noisy ventilation, and neurally adjusted ventilatory assistance (NAVA). In summary, we suggest that assisted MV can be used in ARDS patients in the following situations: (1) Pao(2)/Fio(2) >150 mm Hg and positive end-expiratory pressure ≥ 5 cm H(2)O and (2) with modalities of pressure-targeted and time-cycled breaths including more or less spontaneous or supported breaths (A-PCV [assisted pressure-controlled ventilation] or APRV). Furthermore, during assisted MV, the following parameters should be monitored: inspiratory drive, transpulmonary pressure, and tidal volume (6 mL/kg). Further studies are required to determine the impact of novel modalities of assisted ventilation such as PAV, noisy pressure support, and NAVA on VALI. PMID:25105820

  1. Mechanically Activated Ion Channels.

    PubMed

    Ranade, Sanjeev S; Syeda, Ruhma; Patapoutian, Ardem

    2015-09-23

    Mechanotransduction, the conversion of physical forces into biochemical signals, is essential for various physiological processes such as the conscious sensations of touch and hearing, and the unconscious sensation of blood flow. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels. PMID:26402601

  2. Clinical review: Respiratory mechanics in spontaneous and assisted ventilation

    PubMed Central

    Grinnan, Daniel C; Truwit, Jonathon Dean

    2005-01-01

    Pulmonary disease changes the physiology of the lungs, which manifests as changes in respiratory mechanics. Therefore, measurement of respiratory mechanics allows a clinician to monitor closely the course of pulmonary disease. Here we review the principles of respiratory mechanics and their clinical applications. These principles include compliance, elastance, resistance, impedance, flow, and work of breathing. We discuss these principles in normal conditions and in disease states. As the severity of pulmonary disease increases, mechanical ventilation can become necessary. We discuss the use of pressure–volume curves in assisting with poorly compliant lungs while on mechanical ventilation. In addition, we discuss physiologic parameters that assist with ventilator weaning as the disease process abates. PMID:16277736

  3. Active gated imaging in driver assistance system

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  4. Mechanism of chromophore assisted laser inactivation employing fluorescent proteins.

    PubMed

    McLean, Mark A; Rajfur, Zenon; Chen, Zaozao; Humphrey, David; Yang, Bing; Sligar, Stephen G; Jacobson, Ken

    2009-03-01

    Chromophore assisted laser inactivation (CALI) is a technique that uses irradiation of chromophores proximate to a target protein to inactivate function. Previously, enhanced green fluorescent protein (EGFP) mediated CALI has been used to inactivate EGFP-fusion proteins in a spatio-temporally defined manner within cells, but the mechanism of inactivation is unknown. To help elucidate the mechanism of protein inactivation mediated by fluorescent protein CALI ([FP]-CALI), the activities of purified glutathione-S-transferase-FP (GST-EXFP) fusions were measured after laser irradiation in vitro. Singlet oxygen and free radical quenchers as well as the removal of oxygen inhibited CALI, indicating the involvement of a reactive oxygen species (ROS). At higher concentrations of protein, turbidity after CALI increased significantly indicating cross-linking of proximate fusion proteins suggesting that damage of residues on the surface of the protein, distant from the active site, results in inactivation. Control experiments removed sample heating as a possible cause of these effects. Different FP mutants fused to GST vary in their CALI efficiency in the order enhanced green fluorescent protein (EGFP) > enhanced yellow fluorescent protein (EYFP) > enhanced cyan fluorescent protein (ECFP), while a GST construct that binds fluorescein-based arsenical hairpin binder (FlAsH) results in significantly higher CALI efficiency than any of the fluorescent proteins (XFPs) tested. It is likely that the hierarchy of XFP effectiveness reflects the balance between ROS that are trapped within the XFP structure and cause fluorophore and chromophore bleaching and those that escape to effect CALI of proximate proteins. PMID:19199572

  5. [Importance of mechanical assist devices in acute circulatory arrest].

    PubMed

    Ferrari, Markus Wolfgang

    2016-03-01

    Mechanical assist devices are indicated for hemodynamic stabilization in acute circulatory arrest if conventional means of cardiopulmonary resuscitation are unable to re-establish adequate organ perfusion. Their temporary use facilitates further diagnostic and therapeutic options in selected patients, e.g. coronary angiography followed by revascularization.External thorax compression devices allow sufficient cardiac massage in case of preclinical or in-hospital circulatory arrest, especially under complex transfer conditions. These devices perform standardized thorax compressions at a rate of 80-100 per minute. Invasive mechanical support devices are used in the catheter laboratory or in the intensive care unit. Axial turbine pumps, e.g. the Impella, continuously pump blood from the left ventricle into the aortic root. The Impella can also provide right ventricle support by pumping blood from the vena cava into the pulmonary artery. So-called emergency systems or ECMO devices consist of a centrifugal pump and a membrane oxygenator allowing complete takeover of cardiac and pulmonary functions. Withdrawing blood from the right atrium and vena cava, oxygenated blood is returned to the abdominal aorta. Isolated centrifugal pumps provide left heart support without an oxygenator after transseptal insertion of a venous cannula into the left atrium.Mechanical assist devices are indicated for acute organ protection and hemodynamic stabilization for diagnostic and therapeutic measures as well as bridge to myocardial recovery. Future technical developments and better insights into the pathophysiology of mechanical circulatory support will broaden the spectrum of indications of such devices in acute circulatory arrest. PMID:26860409

  6. Effects of Equine Assisted Activities on Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Lanning, Beth A.; Baier, Margaret E. Matyastik; Ivey-Hatz, Julie; Krenek, Nancy; Tubbs, Jack D.

    2014-01-01

    Quality of life assessments were used in this study to determine the behavioral changes of children diagnosed with autism spectrum disorder (ASD) who participated in equine assisted activities. Behavioral changes of children with ASD participating in 9 weeks of equines assisted activities (EAA) (N = 10) were compared to behavioral changes of…

  7. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily activity assist device. (a) Identification....

  8. Neuroreceptor Activation by Vibration-Assisted Tunneling

    PubMed Central

    Hoehn, Ross D.; Nichols, David; Neven, Hartmut; Kais, Sabre

    2015-01-01

    G protein-coupled receptors (GPCRs) constitute a large family of receptor proteins that sense molecular signals on the exterior of a cell and activate signal transduction pathways within the cell. Modeling how an agonist activates such a receptor is fundamental for an understanding of a wide variety of physiological processes and it is of tremendous value for pharmacology and drug design. Inelastic electron tunneling spectroscopy (IETS) has been proposed as a model for the mechanism by which olfactory GPCRs are activated by a bound agonist. We apply this hyothesis to GPCRs within the mammalian nervous system using quantum chemical modeling. We found that non-endogenous agonists of the serotonin receptor share a particular IET spectral aspect both amongst each other and with the serotonin molecule: a peak whose intensity scales with the known agonist potencies. We propose an experiential validation of this model by utilizing lysergic acid dimethylamide (DAM-57), an ergot derivative, and its deuterated isotopologues; we also provide theoretical predictions for comparison to experiment. If validated our theory may provide new avenues for guided drug design and elevate methods of in silico potency/activity prediction. PMID:25909758

  9. Neuroreceptor activation by vibration-assisted tunneling.

    PubMed

    Hoehn, Ross D; Nichols, David; Neven, Hartmut; Kais, Sabre

    2015-01-01

    G protein-coupled receptors (GPCRs) constitute a large family of receptor proteins that sense molecular signals on the exterior of a cell and activate signal transduction pathways within the cell. Modeling how an agonist activates such a receptor is fundamental for an understanding of a wide variety of physiological processes and it is of tremendous value for pharmacology and drug design. Inelastic electron tunneling spectroscopy (IETS) has been proposed as a model for the mechanism by which olfactory GPCRs are activated by a bound agonist. We apply this hyothesis to GPCRs within the mammalian nervous system using quantum chemical modeling. We found that non-endogenous agonists of the serotonin receptor share a particular IET spectral aspect both amongst each other and with the serotonin molecule: a peak whose intensity scales with the known agonist potencies. We propose an experiential validation of this model by utilizing lysergic acid dimethylamide (DAM-57), an ergot derivative, and its deuterated isotopologues; we also provide theoretical predictions for comparison to experiment. If validated our theory may provide new avenues for guided drug design and elevate methods of in silico potency/activity prediction. PMID:25909758

  10. Mechanically Active Electrospun Materials

    NASA Astrophysics Data System (ADS)

    Robertson, Jaimee M.

    Electrospinning, a technique used to fabricate small diameter polymer fibers, has been employed to develop unique, active materials falling under two categories: (1) shape memory elastomeric composites (SMECs) and (2) water responsive fiber mats. (1) Previous work has characterized in detail the properties and behavior of traditional SMECs with isotropic fibers embedded in an elastomer matrix. The current work has two goals: (i) characterize laminated anisotropic SMECs and (ii) develop a fabrication process that is scalable for commercial SMEC manufacturing. The former ((i)) requires electrospinning aligned polymer fibers. The aligned fibers are similarly embedded in an elastomer matrix and stacked at various fiber orientations. The resulting laminated composite has a unique response to tensile deformation: after stretching and releasing, the composite curls. This curling response was characterized based on fiber orientation. The latter goal ((ii)) required use of a dual-electrospinning process to simultaneously electrospin two polymers. This fabrication approach incorporated only industrially relevant processing techniques, enabling the possibility of commercial application of a shape memory rubber. Furthermore, the approach had the added benefit of increased control over composition and material properties. (2) The strong elongational forces experienced by polymer chains during the electrospinning process induce molecular alignment along the length of electrospun fibers. Such orientation is maintained in the fibers as the polymer vitrifies. Consequently, residual stress is stored in electrospun fiber mats and can be recovered by heating through the polymer's glass transition temperature. Alternatively, the glass transition temperature can be depressed by introducing a plasticizing agent. Poly(vinyl acetate) (PVAc) is plasticized by water, and its glass transition temperature is lowered below room temperature. Therefore, the residual stress can be relaxed at room

  11. Nucleophile-Assisted Alkene Activation: Olefins Alone Are Often Incompetent.

    PubMed

    Ashtekar, Kumar Dilip; Vetticatt, Mathew; Yousefi, Roozbeh; Jackson, James E; Borhan, Babak

    2016-07-01

    Emerging work on organocatalytic enantioselective halocyclizations naturally draws on conditions where both new bonds must be formed under delicate control, the reaction regime where the concerted nature of the AdE3 mechanism is of greatest importance. Without assistance, many simple alkene substrates react slowly or not at all with conventional halenium donors under synthetically relevant reaction conditions. As demonstrated earlier by Shilov, Cambie, Williams, Fahey, and others, alkenes can undergo a concerted AdE3-type reaction via nucleophile participation, which sets the configuration of the newly created stereocenters at both ends in one step. Herein, we explore the modulation of alkene reactivity and halocyclization rates by nucleophile proximity and basicity, through detailed analyses of starting material spectroscopy, addition stereopreferences, isotope effects, and nucleophile-alkene interactions, all obtained in a context directly relevant to synthesis reaction conditions. The findings build on the prior work by highlighting the reactivity spectrum of halocyclizations from stepwise to concerted, and suggest strategies for design of new reactions. Alkene reactivity is seen to span the range from the often overgeneralized "sophomore textbook" image of stepwise electrophilic attack on the alkene and subsequent nucleophilic bond formation, to the nucleophile-assisted alkene activation (NAAA) cases where electron donation from the nucleophilic addition partner activates the alkene for electrophilic attack. By highlighting the factors that control reactivity across this range, this study suggests opportunities to explain and control stereo-, regio-, and organocatalytic chemistry in this important class of alkene additions. PMID:27284808

  12. Environment assisted degradation mechanisms in aluminum-lithium alloys

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Stoner, Glenn E.; Swanson, Robert E.

    1988-01-01

    Section 1 of this report records the progress achieved on NASA-LaRC Grant NAG-1-745 (Environment Assisted Degradation Mechanisms in Al-Li Alloys), and is based on research conducted during the period April 1 to November 30, 1987. A discussion of work proposed for the project's second year is included. Section 2 provides an overview of the need for research on the mechanisms of environmental-mechanical degradation of advanced aerospace alloys based on aluminum and lithium. This research is to provide NASA with the basis necessary to permit metallurgical optimization of alloy performance and engineering design with respect to damage tolerance, long term durability and reliability. Section 3 reports on damage localization mechanisms in aqueous chloride corrosion fatigue of aluminum-lithium alloys. Section 4 reports on progress made on measurements and mechanisms of localized aqueous corrosion in aluminum-lithium alloys. Section 5 provides a detailed technical proposal for research on environmental degradation of Al-Li alloys, and the effect of hydrogen in this.

  13. Pulsatile mechanical cardiac assistance in pediatric patients with the Berlin heart ventricular assist device.

    PubMed

    Merkle, Frank; Boettcher, Wolfgang; Stiller, Brigitte; Hetzer, Roland

    2003-06-01

    Mechanical cardiac assistance for neonates, infants, children and adolescents may be accomplished with pulsatile ventricular assist devices (VAD) instead of extracorporeal membrane oxygenation or centrifugal pumps. The Berlin Heart VAD consists of extracorporeal, pneumatically driven blood pumps for pulsatile univentricular or biventricular assistance for patients of all age groups. The blood pumps are heparin-coated. The stationary driving unit (IKUS) has the required enhanced compressor performance for pediatric pump sizes. The Berlin Heart VAD was used in a total number of 424 patients from 1987 to November 2001 at our institution. In 45 pediatric patients aged 2 days-17 years the Berlin Heart VAD was applied for long-term support (1-111 days, mean 20 days). There were three patient groups: Group I: "Bridge to transplantation" with various forms of cardiomyopathy (N = 21) or chronic stages of congenital heart disease (N = 9); Group II: "Rescue" in intractable heart failure after corrective surgery for congenital disease (N = 7) or in early graft failure after heart transplantation (N = 1); and Group III: "Acute myocarditis" (N = 7) as either bridge to transplantation or bridge to recovery. Seventeen patients were transplanted after support periods of between 4 and 111 days with 12 long-term survivors, having now survived for up to 10 years. Five patients (Groups I and III) were weaned from the system with four long-term survivors. In Group II only one patient survived after successful transplantation. Prolonged circulatory support with the Berlin Heart VAD is an effective method for bridging until cardiac recovery or transplantation in the pediatric age group. Extubation, mobilization, and enteral nutrition are possible. For long-term use, the Berlin Heart VAD offers advantages over centrifugal pumps and ECMO in respect to patient mobility and safety. PMID:12939019

  14. A mechanically assisted heat pipe using micro-pumps

    SciTech Connect

    Wong, J.L.; Campbell, G.; Hassapis, C.; Chang, W.S.

    1996-12-31

    A new mechanically assisted heat pipe has been developed and tested by the authors that combines the high performance of a pumped fluid loop with the reliability of passive heat pipes. The new unit employs micro-pumps inside a passive heat pipe to enhance the return of working fluid from the condenser to the evaporator, and thereby increases the capability of the system. This hybrid device is lighter, smaller and handles higher heat flux compared with a passive heat pipe of similar weight and dimensions. Best of all, if the mechanical pump fails, the heat transport will be impaired, but not totally paralyzed, allowing some form of lower level operation. This micro-pump design installs fins at critical locations inside the heat pipe. These fins can be parallel (flag) or perpendicular (flap) to the flow direction. By vibrating these fins in a motion similar to dolphin kicks for the flaps, and in a motion similar to a fishtail for the flags, these fins were found capable of pumping the working fluid effectively. The size and geometry of these fins were tested extensively. Several actuation approaches were examined. The results of these tests are presented in this paper.

  15. Performance Assessment Assistance Activities in the DOE Complex - 12325

    SciTech Connect

    Seitz, Roger R.; Phifer, Mark A.; Letourneau, Martin J.

    2012-07-01

    The United States Department of Energy Office of Environmental Management (DOE-EM) has established a Performance Assessment Community of Practice (PA CoP) to foster the sharing of information among performance assessment (PA) and risk assessment practitioners, regulators and oversight personnel. The general intent is to contribute to continuous improvement in the consistency, technical adequacy and quality of implementation of PAs and risk assessments around the DOE Complex. The PA CoP activities have involved commercial disposal facilities and international participants to provide a global perspective. The PA CoP has also sponsored annual technical exchanges as a means to foster improved communication and to share lessons learned from on-going modelling activities. The PA CoP encourages activities to provide programmatic and technical assistance in the form of sharing experience and lessons learned with practitioners during the development of PAs and risk assessments. This assistance complements DOE-EM reviews through the Low-Level Waste Disposal Facility Federal Review Group (LFRG) that are conducted after modelling efforts are completed. Such up-front assistance is providing additional value in terms of improving consistency and sharing of information. There has been a substantial increase in the amount of assistance being provided. The assistance has been well received by practitioners and regulators that have been involved. The paper highlights assistance and sharing of information that has been conducted in the last two years to support activities underway in support of proposed disposal facilities at Paducah, Portsmouth, and the Idaho National Laboratory and tank closure at Hanford. DOE-EM established the PA CoP to help improve the consistency and quality of implementation of modelling activities around the DOE Complex. The PA CoP has sponsored annual technical exchanges as a means to foster improved communication and to share lessons learned from ongoing

  16. Molecular mechanisms of microglial activation.

    PubMed

    Zielasek, J; Hartung, H P

    1996-01-01

    Microglial cells are brain macrophages which serve specific functions in the defense of the central nervous system (CNS) against microorganisms, the removal of tissue debris in neurodegenerative diseases or during normal development, and in autoimmune inflammatory disorders of the brain. In cultured microglial cells, several soluble inflammatory mediators such as cytokines and bacterial products like lipopolysaccharide (LPS) were demonstrated to induce a wide range of microglial activities, e.g. increased phagocytosis, chemotaxis, secretion of cytokines, activation of the respiratory burst and induction of nitric oxide synthase. Since heightened microglial activation was shown to play a role in the pathogenesis of experimental inflammatory CNS disorders, understanding the molecular mechanisms of microglial activation may lead to new treatment strategies for neurodegenerative disorders, multiple sclerosis and bacterial or viral infections of the nervous system. PMID:8876774

  17. Thermal and thermo-mechanical simulation of laser assisted machining

    SciTech Connect

    Germain, G.; Dal Santo, P.; Lebrun, J. L.; Bellett, D.; Robert, P.

    2007-04-07

    Laser Assisted Machining (LAM) improves the machinability of materials by locally heating the workpiece just prior to cutting. The heat input is provided by a high power laser focused several millimeters in front of the cutting tool. Experimental investigations have confirmed that the cutting force can be decreased, by as much as 40%, for various materials (tool steel, titanium alloys and nickel alloys). The laser heat input is essentially superficial and results in non-uniform temperature profiles within the depth of the workpiece. The temperature field in the cutting zone is therefore influenced by many parameters. In order to understand the effect of the laser on chip formation and on the temperature fields in the different deformation zones, thermo-mechanical simulation were undertaken. A thermo-mechanical model for chip formation with and without the laser was also undertaken for different cutting parameters. Experimental tests for the orthogonal cutting of 42CrMo4 steel were used to validate the simulation via the prediction of the cutting force with and without the laser. The thermo-mechanical model then allowed us to highlight the differences in the temperature fields in the cutting zone with and without the laser. In particular, it was shown that for LAM the auto-heating of the material in the primary shear zone is less important and that the friction between the tool and chip also generates less heat. The temperature fields allow us to explain the reduction in the cutting force and the resulting residual stress fields in the workpiece.

  18. Microwave-assisted regeneration of activated carbon.

    PubMed

    Foo, K Y; Hameed, B H

    2012-09-01

    Microwave heating was used in the regeneration of methylene blue-loaded activated carbons produced from fibers (PFAC), empty fruit bunches (EFBAC) and shell (PSAC) of oil palm. The dye-loaded carbons were treated in a modified conventional microwave oven operated at 2450 MHz and irradiation time of 2, 3 and 5 min. The virgin properties of the origin and regenerated activated carbons were characterized by pore structural analysis and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement and determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue (MB). Microwave irradiation preserved the pore structure, original active sites and adsorption capacity of the regenerated activated carbons. The carbon yield and the monolayer adsorption capacities for MB were maintained at 68.35-82.84% and 154.65-195.22 mg/g, even after five adsorption-regeneration cycles. The findings revealed the potential of microwave heating for regeneration of spent activated carbons. PMID:22728787

  19. Catalog of organizations that assist inventors: Activities and services

    SciTech Connect

    Not Available

    1988-03-01

    This catalog is part of Argonne National Laboratory's ongoing Study of Innovative Programs for Inventors, sponsored by the Energy Related Inventions Program of the US Department of Energy. One of the goals of the study is to facilitate the exchange of information among inventor assistance organizations. This catalog summarizes activities and services of 99 national (but nonfederal), state, and local organizations and programs that assist independent inventors or inventors associated with small businesses. The entries are grouped by state. Following the summaries is a cross-reference index that uses the identification number to group organizations by service or activity (e.g., publishing a newsletter).

  20. Active motion assisted by correlated stochastic torques.

    PubMed

    Weber, Christian; Radtke, Paul K; Schimansky-Geier, Lutz; Hänggi, Peter

    2011-07-01

    The stochastic dynamics of an active particle undergoing a constant speed and additionally driven by an overall fluctuating torque is investigated. The random torque forces are expressed by a stochastic differential equation for the angular dynamics of the particle determining the orientation of motion. In addition to a constant torque, the particle is supplemented by random torques, which are modeled as an Ornstein-Uhlenbeck process with given correlation time τ(c). These nonvanishing correlations cause a persistence of the particles' trajectories and a change of the effective spatial diffusion coefficient. We discuss the mean square displacement as a function of the correlation time and the noise intensity and detect a nonmonotonic dependence of the effective diffusion coefficient with respect to both correlation time and noise strength. A maximal diffusion behavior is obtained if the correlated angular noise straightens the curved trajectories, interrupted by small pirouettes, whereby the correlated noise amplifies a straightening of the curved trajectories caused by the constant torque. PMID:21867138

  1. PERFORMANCE ASSESSMENT ASSISTANCE ACTIVITIES IN THE DOE COMPLEX

    SciTech Connect

    Seitz, R.

    2012-01-23

    The United States Department of Energy Office of Environmental Management (DOE-EM) has established a Performance Assessment Community of Practice (PA CoP) to foster the sharing of information among performance assessment (PA) and risk assessment practitioners, regulators and oversight personnel. The general intent is to contribute to continuous improvement in the consistency, technical adequacy and quality of implementation of PAs and risk assessments around the DOE Complex. The PA CoP activities have involved commercial disposal facilities and international participants to provide a global perspective. The PA CoP has also sponsored annual technical exchanges as a means to foster improved communication and to share lessons learned from on-going modelling activities. The PA CoP encourages activities to provide programmatic and technical assistance in the form of sharing experience and lessons learned with practitioners during the development of PAs and risk assessments. This assistance complements DOE-EM reviews through the Low-Level Waste Disposal Facility Federal Review Group (LFRG) that are conducted after modelling efforts are completed. Such up-front assistance is providing additional value in terms of improving consistency and sharing of information. There has been a substantial increase in the amount of assistance being provided. The assistance has been well received by practitioners and regulators that have been involved. The paper highlights assistance and sharing of information that has been conducted in the last two years to support activities underway in support of proposed disposal facilities at Paducah, Portsmouth, and the Idaho National Laboratory and tank closure at Hanford.

  2. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  3. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  4. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  5. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  6. 78 FR 64414 - Assistance to Foreign Atomic Energy Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-29

    ... concerning Assistance to Foreign Atomic Energy Activities since 1986. (76 FR 55278) The NOPR reflected a need.... ] DATES: DOE will continue to accept written comments on the SNOPR published August 2, 2013 (78 FR 46829... a second opportunity to comment. (78 FR 46829) II. Second Public Meeting A public meeting on...

  7. 76 FR 65634 - Assistance to Foreign Atomic Energy Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ... Proposed Rulemaking (76 FR 55278). FOR FURTHER INFORMATION CONTACT: Richard Goorevich, National Nuclear Security Administration, U.S. Department of Energy, Office of Defense Nuclear Nonproliferation (NA-20... assistance to foreign atomic energy activities (76 FR 55278). This regulation provides that persons...

  8. [Active euthanasia in Colombia and assisted suicide in California].

    PubMed

    Julesz, Máté

    2016-01-31

    The institution of active euthanasia has been legal in Colombia since 2015. In California, the regulation on physician-assisted suicide will come into effect on January 1, 2016. The legal institution of active euthanasia is not accepted under the law of the United States of America, however, physician-assisted suicide is accepted in an increasing number of member states. The related regulation in Oregon is imitated in other member states. In South America, Colombia is not the first country to legalize active euthanasia: active euthanasia has been legal in Uruguay since 1932. The North American legal tradition markedly differs from the South American one and both are incompatible with the Central European rule of law. In Hungary and in most European Union countries, solely the passive form of euthanasia is legal. In the Benelux countries, the active form of euthanasia is legal because the supranational law of the European Union does not prohibit it. Notwithstanding, European Union law does not prescribe legalization of either the active form of euthanasia, or the physician-assisted suicide. PMID:26801362

  9. 77 FR 67804 - Agency Information Collection Activities; Comment Request; Application for Client Assistance Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-14

    ... Agency Information Collection Activities; Comment Request; Application for Client Assistance Program... notice will be considered public records. Title of Collection: Application for Client Assistance Program... request funds to establish and carry out Client Assistance Programs (CAP). CAP is mandated by...

  10. The mechanism of galvanic/metal-assisted etching of silicon

    PubMed Central

    2014-01-01

    Metal-assisted etching is initiated by hole injection from an oxidant catalyzed by a metal nanoparticle or film on a Si surface. It is shown that the electronic structure of the metal/Si interface, i.e., band bending, is not conducive to diffusion of the injected hole away from the metal in the case of Ag or away from the metal/Si interface in the cases of Au, Pd, and Pt. Since holes do not diffuse away from the metals, the electric field resulting from charging of the metal after hole injection must instead be the cause of metal-assisted etching. PMID:25221459

  11. Substrate-Assisted Cysteine Deprotonation in the Mechanism of Dimethylargininase (DDAH) from Pseudomonas aeruginosa

    SciTech Connect

    Stone,E.; Costello, A.; Tierney, D.; Fast, W.

    2006-01-01

    The enzyme dimethylargininase (also known as dimethylarginine dimethylaminohydrolase or DDAH; EC 3.5.3.18) catalyzes the hydrolysis of endogenous nitric oxide synthase inhibitors, N{sup {omega}}-methyl-L-arginine and N{sup {omega}},N{sup {omega}}-dimethyl-L-arginine. Understanding the mechanism and regulation of DDAH activity is important for developing ways to control nitric oxide production during angiogenesis and in many cases of vascular endothelial pathobiology. Several possible physiological regulation mechanisms of DDAH depend upon the presence of an active-site cysteine residue, Cys249 in Pseudomonas aeruginosa (Pa) DDAH, which is proposed to serve as a nucleophile in the catalytic mechanism. Through the use of pH-dependent ultraviolet and visible (UV-vis) difference spectroscopy and inactivation kinetics, the pK{sub a} of the active-site Cys249 in the resting enzyme was found to be unperturbed from pK{sub a} values of typical noncatalytic cysteine residues. In contrast, the pH dependence of k{sub cat} values indicates a much lower apparent pKa value. UV-vis difference spectroscopy between wild-type and C249S DDAH shows absorbance changes consistent with Cys249 deprotonation to the anionic thiolate upon binding positively charged ligands. The proton from Cys249 is lost either to the solvent or to an unidentified general base. A mutation of the active-site histidine residue, H162G, does not eliminate cysteine nucleophilicity, further arguing against a pre-formed ion pair with Cys249. Finally, UV-vis and X-ray absorption spectroscopy revealed that inhibitory metal ions can bind at these two active-site residues, Cys249 and His162, and also stabilize the anionic form of Cys249. These results support a proposed substrate-assisted mechanism for Pa DDAH in which ligand binding modulates the reactivity of the active-site cysteine.

  12. MemoPA: Intelligent Personal Assistant Agents with a Case Memory Mechanism

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jia; Barthès, Jean-Paul

    A Personal Assistant (PA) agent is a software agent capable of helping people to handle tasks in their workplace. The paper proposes a memory mechanism for personal assistant agents in order to enhance agent intelligence while working with the user or with other agents. Inspired by a case memory model in the domain of Case-Based Reasoning (CBR), this paper endows PA agents with a case memory mechanism, which results in improved PA agents: MemoPAs. We present the memory mechanism of MemoPA in detail, and report a first implementation of the method. Finally, future work is outlined for improving the memory mechanism.

  13. Brillouin microspectroscopy of nanostructured biomaterials: photonics assisted tailoring mechanical properties

    NASA Astrophysics Data System (ADS)

    Meng, Zhaokai; Jaiswal, Manish K.; Chitrakar, Chandani; Thakur, Teena; Gaharwar, Akhilesh K.; Yakovlev, Vladislav V.

    2016-03-01

    Developing new biomaterials is essential for the next-generation of materials for bioenergy, bioelectronics, basic biology, medical diagnostics, cancer research, and regenerative medicine. Specifically, recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. The physical properties of nanocomposite biomaterials, including elasticity and viscosity, play key roles in controlling cell fate, which underlines therapeutic success. Conventional mechanical tests, including uniaxial compression and tension, dynamic mechanical analysis and shear rheology, require mechanical forces to be directly exerted onto the sample and therefore may not be suitable for in situ measurements or continuous monitoring of mechanical stiffness. In this study, we employ spontaneous Brillouin spectroscopy as a viscoelasticity-specific probing technique. We utilized a Brillouin spectrometer to characterize biomaterial's microscopic elasticity and correlated those with conventional mechanical tests (e.g., rheology).

  14. [Mechanical circulatory assist using a miniaturized Archimedes screw].

    PubMed

    von Segesser, L K; Bisang, B; Leskosek, B; Turina, M

    1991-01-01

    An axial flow blood pump (Archimedes screw) for intraarterial left ventricular assist was evaluated in comparison to standard roller pump left heart bypass (LHBP) in 13 bovine experiments (bodyweight 74 +/- 15 kg). Full systemic heparinization (ACT greater than 500 s) was used for LHBP in comparison to limited systemic heparinization (ACT greater than 180 s) for axial. A standard battery of blood samples was taken before and at regular intervals throughout perfusion: (table; see text) Transarterial access and relatively limited blood trauma appear to be the main advantages of the evaluated axial flow blood pump. However, the impossibility to assess the pump flow may be a major problem for the management of the failing left ventricle. PMID:2050534

  15. Environment assisted degradation mechanisms in advanced light metals

    NASA Technical Reports Server (NTRS)

    Gangloff, R. P.; Stoner, G. E.; Swanson, R. E.

    1989-01-01

    A multifaceted research program on the performance of advanced light metallic alloys in aggressive aerospace environments, and associated environmental failure mechanisms was initiated. The general goal is to characterize alloy behavior quantitatively and to develop predictive mechanisms for environmental failure modes. Successes in this regard will provide the basis for metallurgical optimization of alloy performance, for chemical control of aggressive environments, and for engineering life prediction with damage tolerance and long term reliability.

  16. Plasma Assisted Combustion Mechanism for Hydrogen and Small Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Starikovskiy, Andrey; Aleksandrov, Nikolay

    2015-09-01

    The main mechanisms of nonequilibrium gas excitation and their influence on the ignition and combustion were briefly discussed. Rotational excitation, vibrational excitation, electronic excitation, dissociation by electron impact and ionization were all analyzed, as well as the ways in which the selectivity of the gas excitation in the discharge can be controlled. The model consists of two parts. The first part describes gas excitation by electron impact - rotational, vibrational and electronic states population by pulsed discharges. The second part considers energy relaxation in the plasma (formation of Maxwell-Boltzmann equilibrium across translational, vibrational and electronic degrees of freedom of molecules), quenching and decomposition of excited states, their reactions and recombination - with formation of thermally-equilibrium pool of radicals, which could be considered as initial conditions for any detailed combustion kinetic mechanism. The mechanism was verified against available kinetic data in a wide temperature range. Despite of some lack of knowledge of mechanism details, nonequilibrium plasma demonstrates great potential for controlling ultra-lean, ultra-fast, low-temperature flames and is an extremely promising technology for a very wide range of applications.

  17. Environment assisted degradation mechanisms in advanced light metals

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Stoner, Glenn E.; Swanson, Robert E.

    1988-01-01

    The general goals of the research program are to characterize alloy behavior quantitatively and to develop predictive mechanisms for environmental failure modes. Successes in this regard will provide the basis for metallurgical optimization of alloy performance, for chemical control of aggressive environments, and for engineering life prediction with damage tolerance and long term reliability.

  18. Photon assisted hopping conduction mechanism in Tl2SSe crystals

    NASA Astrophysics Data System (ADS)

    Qasrawi, A. F.; Ziqan, Abdelhalim M.; Jazzar, Suha Kh.; Gasanly, N. M.

    2015-02-01

    In this article, the powder X-ray diffraction data and the dark and the photo-excited electrical conduction parameters of Tl2SSe crystal are reported. The dark and photon excited electrical conduction in the tetragonal crystal are found to be dominated by thermionic emission assisted variable range hopping conduction (VRH). The dark Mott's VRH parameters representing by the degree of disorder (To), the density of localized states near the Fermi level (N (EF)), the average hopping range (R) and average hopping energy (W) exhibited wide tunability via incremental photon intensity. Particularly, while the dark values of T0 , W and R significantly decreased from 2.32 ×108 to 1.52 ×105 K, 114 to 18.25 meV and from 66.15 to 10.58 A°, respectively, the values of N (EF) increased from 7.23 ×1018 to 1.10 ×1022cm-3 /eV when the crystal was photo-excited with a 53.6 mW/cm2 light intensity. These variations in the hopping parameters via photon excitations are promisig for using the crystal in the fabrication of well controlled, widely tunable, low energy consuming and highly efficient electronic devices.

  19. Water Assisted Reaction Mechanism of OH- with CCl4 in Aqueous Solution - Hybrid Quantum Mechanical and Molecular Mechanics Investigation

    SciTech Connect

    Chen, Jie; Yin, Hongyun; Wang, Dunyou; Valiev, Marat

    2013-02-20

    The OH- (H2O) + CCl4 reaction in aqueous solution was investigated using the combined quantum mechanical and molecular mechanics approach. The reaction mechanism of OH- (H2O) + CCl4 consists of two concerted steps - formation of OH- in the favorable attack conformation via the proton transfer process, and the nucleophilic substitution process in which the newly formed OH- attacks the CCl4. The free energy activation barrier is 38.2 kcal/mol at CCSD(T)/MM level of theory for this reaction, which is about 10.3 kcal/mol higher than that of the direct nucleophilic substitution mechanism of the OH- + CCl4 reaction in aqueous solution.

  20. 78 FR 48660 - Agency Information Collection Activities; Comment Request; Student Assistance General Provisions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... Agency Information Collection Activities; Comment Request; Student Assistance General Provisions--Subpart K--Cash Management AGENCY: Federal Student Aid (FSA), Department of Education (ED). ACTION: Notice... notice will be considered public records. Title of Collection: Student Assistance General...

  1. 78 FR 63972 - Agency Information Collection Activities; Comment Request; Student Assistance General Provisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-25

    ... Agency Information Collection Activities; Comment Request; Student Assistance General Provisions AGENCY: Federal Student Aid (FSA), Department of Education (ED). ACTION: Notice. SUMMARY: In accordance with the... considered public records. Title of Collection: Student Assistance General Provisions. OMB Control...

  2. 75 FR 9928 - Bureau of Justice Assistance; Agency Information Collection Activities: Proposed Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Office of Justice Programs Bureau of Justice Assistance; Agency Information Collection Activities: Proposed... currently approved collection. Bureau of Justice Assistance Application Form: ] Public Safety...

  3. Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

    PubMed

    Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

    2016-11-15

    The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. PMID:27450342

  4. Cavopulmonary assist for the failing Fontan circulation: Impact of ventricular function on mechanical support strategy

    PubMed Central

    Giridharan, Guruprasad A; Ising, Mickey; Sobieski, Michael A.; Koenig, Steven C; Chen, Jun; Frankel, Steven; Rodefeld, Mark D

    2015-01-01

    Mechanical circulatory support - either ventricular assist device (VAD, left-sided systemic support) or cavopulmonary assist device (CPAD, right-sided support) - has been suggested as treatment for Fontan failure. The selection of left- vs. right-sided support for failing Fontan has not been previously defined. Computer simulation and mock circulation models of pediatric Fontan patients (15–25 kg) with diastolic, systolic, and combined systolic and diastolic dysfunction were developed. The global circulatory response to assisted Fontan flow using VAD (HeartWare HVAD, FL) support, CPAD (Viscous Impeller Pump, IN) support, and combined VAD and CPAD support were evaluated. Cavopulmonary assist improves failing Fontan circulation during diastolic dysfunction but preserved systolic function. In the presence of systolic dysfunction and elevated ventricular end-diastolic pressure (VEDP), VAD support augments cardiac output and diminishes VEDP, while increased preload with cavopulmonary assist may worsen circulatory status. Fontan circulation can be stabilized to biventricular values with modest cavopulmonary assist during diastolic dysfunction. Systemic VAD support may be preferable to maintain systemic output during systolic dysfunction. Both systemic and cavopulmonary support may provide best outcome during combined systolic and diastolic dysfunction. These findings may be useful to guide clinical cavopulmonary assist strategies in failing Fontan circulations. PMID:25158887

  5. Cavopulmonary assist for the failing Fontan circulation: impact of ventricular function on mechanical support strategy.

    PubMed

    Giridharan, Guruprasad A; Ising, Mickey; Sobieski, Michael A; Koenig, Steven C; Chen, Jun; Frankel, Steven; Rodefeld, Mark D

    2014-01-01

    Mechanical circulatory support--either ventricular assist device (VAD, left-sided systemic support) or cavopulmonary assist device (CPAD, right-sided support)--has been suggested as treatment for Fontan failure. The selection of left- versus right-sided support for failing Fontan has not been previously defined. Computer simulation and mock circulation models of pediatric Fontan patients (15-25 kg) with diastolic, systolic, and combined systolic and diastolic dysfunction were developed. The global circulatory response to assisted Fontan flow using VAD (HeartWare HVAD, Miami Lakes, FL) support, CPAD (Viscous Impeller Pump, Indianapolis, IN) support, and combined VAD and CPAD support was evaluated. Cavopulmonary assist improves failing Fontan circulation during diastolic dysfunction but preserved systolic function. In the presence of systolic dysfunction and elevated ventricular end-diastolic pressure (VEDP), VAD support augments cardiac output and diminishes VEDP, while increased preload with cavopulmonary assist may worsen circulatory status. Fontan circulation can be stabilized to biventricular values with modest cavopulmonary assist during diastolic dysfunction. Systemic VAD support may be preferable to maintain systemic output during systolic dysfunction. Both systemic and cavopulmonary support may provide best outcome during combined systolic and diastolic dysfunction. These findings may be useful to guide clinical cavopulmonary assist strategies in failing Fontan circulations. PMID:25158887

  6. Effect of Mechanical Assistance of the Systemic Ventricle in Single Ventricle Circulation with Cavopulmonary Connection

    PubMed Central

    Sinha, Pranava; Deutsch, Nina; Ratnayaka, Kanishka; He, Dingchao; Zurakowski, Mark Nuszkowski David; Jonas, Richard

    2014-01-01

    Background Previous attempts to support the single ventricle circulation mechanically have suggested that a custom-built assist device is needed to push rather than pull through the pulmonary circulation. We hypothesized that using a conventional ventricular assist device, with or without conversion of a total cavopulmonary connection to a bidirectional Glenn cavopulmonary connection would allow assistance by pulling blood through the circuit and improve cardiac index (CI). Methods Cavopulmonary connections were established in each of five Yorkshire pigs (25kg) using ePTFE conduits in a “Y” configuration with appropriate clamping of limbs of the Y to achieve: total cavopulmonary Fontan connection (TCPC), SVC cavopulmonary connection (SVC Glenn) and IVC cavopulmonary connection (IVC Glenn). A common atrium had been established previously by balloon septostomy. Mechanical circulatory assistance of the single systemic ventricle was achieved using a centrifugal pump with common atrial inflow and proximal ascending aortic outflow. CI was calculated using an ultrasonic flow meter placed on the distal ascending aorta and compared between assisted and non-assisted circulation for 3 conditions: TCPC, SVC Glenn and IVC Glenn. Mean pulmonary artery pressure (PAP), common atrial pressure (LAP), arterial oxygen saturation (SAT), partial pressure of arterial oxygen (PO2) and oxygen delivery (DO2) were calculated. Results Unassisted SVC Glenn CI tended to be higher than TCPC or IVC Glenn (Figure 1). Significant augmentation of total CI was achieved with mechanical assistance for SVC Glenn (109% ± 24%, P =.04) and also with TCPC (130% ± 109%, P = .01). Assisted CI achieved at least mean baseline biventricular CI for all 3-support modes. Oxygen delivery was highest for assisted SVC Glenn 1786 ± 1307 ml/l/min and lowest with TCPC 1146 ± 386 ml/l/min, with a trend toward lower common atrial pressure and lower pulmonary artery pressure for SVC Glenn. Conclusions SVC

  7. Mechanism for the activation of glutamate receptors

    Cancer.gov

    Scientists at the NIH have used a technique called cryo-electron microscopy to determine a molecular mechanism for the activation and desensitization of ionotropic glutamate receptors, a prominent class of neurotransmitter receptors in the brain and spina

  8. Mechanical Design Technology--Modified. (Computer Assisted Drafting, Computer Aided Design). Curriculum Grant 84/85.

    ERIC Educational Resources Information Center

    Schoolcraft Coll., Livonia, MI.

    This document is a curriculum guide for a program in mechanical design technology (computer-assisted drafting and design developed at Schoolcraft College, Livonia, Michigan). The program helps students to acquire the skills of drafters and to interact with electronic equipment, with the option of becoming efficient in the computer-aided…

  9. Mechanism of persulfate activation by phenols.

    PubMed

    Ahmad, Mushtaque; Teel, Amy L; Watts, Richard J

    2013-06-01

    The activation of persulfate by phenols was investigated to further the understanding of persulfate chemistry for in situ chemical oxidation (ISCO). Phenol (pKa = 10.0) activated persulfate at pH 12 but not at pH 8, suggesting activation occurred only via the phenoxide form. Evaluation of the phenoxide activation mechanism was complicated by the concurrent activation of persulfate by hydroperoxide anion, which is generated by the base catalyzed hydrolysis of persulfate. Therefore, phenoxide activation was investigated using pentachlorophenoxide at pH 8.3, midway between the pKa of pentachlorophenol (pKa = 4.8) and that of hydrogen peroxide (pKa = 11.8). Of the two possible mechanisms for phenoxide activation of persulfate (reduction or nucleophilic attack) the results were consistent with reduction of persulfate by phenoxide with oxidation of the phenoxide. The concentration of phenoxide required for maximum persulfate activation was low (1 mM). The results of this research document that phenoxides activate persulfate via reduction; phenolic moieties ubiquitous to soil organic matter in the subsurface may have a significant role in the activation of persulfate during its injection into the subsurface for ISCO. Furthermore, the results provide the foundation for activation of persulfate by other organic anions without the toxicity of phenols, such as keto acids. PMID:23663058

  10. Primary in-series palliation of hypoplastic left heart syndrome with mechanical lung assist in neonatal pigs.

    PubMed

    Merklinger, Sandra L; Honjo, Osami; Al-Radi, Osman O; Poe, John; Wang, Jian; Oka, Norihiko; Van Arsdell, Glen S

    2009-01-01

    Less than optimal outcomes for hypoplastic left heart syndrome may be related to unstable in-parallel circulation. Mechanical lung assist by (1) superior vena cava to right atrium pump with oxygenation (oxygenator assist), or (2) superior vena cava to pulmonary artery pump (pump assist) may permit successful neonatal in-series palliation. Nineteen 15-day-old piglets underwent single ventricle and bidirectional cavopulmonary shunt (BCPC) creation without mechanical lung assist (n = 8), with pump assist (n = 5), or with oxygenator assist (n = 6). Baseline hemodynamic measurements were not different between groups. Median survival for the cavopulmonary shunt alone, pump assist, and oxygenator assist groups was 28, 180, and 180 minutes, respectively (p = 0.0006). No differences in arterial oxygen concentration or bicarbonate levels were detected. Arterial carbon dioxide (p < or = 0.007) was higher in the cavopulmonary shunt alone versus lung assist groups. Cavopulmonary shunt alone animals had decreased mean arterial pressure (p < 0.02) and cerebral perfusion pressure (p = 0.029) and elevated left atrial pressure compared with lung assist groups (p < 0.05). This data demonstrates creation of a novel translational neonatal BCPC model in which mechanical lung assist augments survival. Early BCPC death was related to poor ventricular function and an inability to ventilate, issues that were improved with both types of lung assist. PMID:19812479

  11. Design of Mechanism for Assisting Standing Movement Using Planar Linkage and Gear Train

    NASA Astrophysics Data System (ADS)

    Nango, Jun; Yoshizawa, Hisato; Liu, Jiajun

    The number of people who are in need of nursing care due to difficulties they experience with performing various activities of daily living is increasing. In particular, the action of standing up is performed frequently in daily life, and this action starts to induce pain in joints as people age. In this research, we develop a device whose seat plate follows the movement of the thigh in the action of standing up for the purpose of relieving the burden from the joints and reducing the effort associated with nursing care. The device is designed by using a planar five-link mechanism and a gear train, and only a single input is needed to drive the device. The respective lengths of the links are determined by comparing the movement of the seat plate of the device with the movement of the human thigh in the action of standing up. In addition, this device is expected to be useful for assisting users in standing up in a natural manner, including in the case when the body remains supported by the seat plate, as well as for guiding the individual movements of users in the action of standing up.

  12. Competing activation mechanisms in epidemics on networks

    NASA Astrophysics Data System (ADS)

    Castellano, Claudio; Pastor-Satorras, Romualdo

    2012-04-01

    In contrast to previous common wisdom that epidemic activity in heterogeneous networks is dominated by the hubs with the largest number of connections, recent research has pointed out the role that the innermost, dense core of the network plays in sustaining epidemic processes. Here we show that the mechanism responsible of spreading depends on the nature of the process. Epidemics with a transient state are boosted by the innermost core. Contrarily, epidemics allowing a steady state present a dual scenario, where either the hub independently sustains activity and propagates it to the rest of the system, or, alternatively, the innermost network core collectively turns into the active state, maintaining it globally. In uncorrelated networks the former mechanism dominates if the degree distribution decays with an exponent larger than 5/2, and the latter otherwise. Topological correlations, rife in real networks, may perturb this picture, mixing the role of both mechanisms.

  13. Initial Work Toward A Robotically Assisted Extravehicular Activity Glove

    NASA Technical Reports Server (NTRS)

    Rogers, Jonathan M.; Peters, Benjamin J.; Laske, Evans A.; McBryan, Emily R.

    2016-01-01

    The Space Suit RoboGlove (SSRG) is a glove designed to provide additional grasp strength or endurance for an Extravehicular Activity (EVA) crew member, since a pressurized space suit gloved hand performance is a fraction of what the unencumbered human hand can achieve. There have been past efforts to improve space suit gloved hand performance by employing novel materials and construction techniques to the glove design, as well as integrating powered assistance devices into the gloves. These past efforts were not completely successful and the National Aeronautics and Space Administration (NASA) decided to develop a new glove based on the NASA/General Motors RoboGlove technology. The resulting SSRG used a unique approach to integrate the robotic actuators and sensors into a Phase VI EVA glove that resulted in a space suit glove that provided grasp augmentation to the user while the augmentation is activated, and also functioned as a normal glove when the augmentation is disabled. Care was taken to avoid adding excessive bulk to the glove or affecting tactility by choosing low-profile sensors and locating the actuators at a distance from the fingers. Conduits were used to guide robotic tendons from linear actuators, across the wrist, and to the fingers. The electromechanical design, softgoods integration, control system, and early test results of the first generation SSRG are presented in this paper. These early test results showed that this sensor integration did not impact tactile feedback in the glove and that the actuators provided potential for increased grip strength and reduction in grasp fatigue over time.

  14. Mechanism study of dual-frequency ultrasound assisted enzymolysis on rapeseed protein by immobilized Alcalase.

    PubMed

    Wang, Bei; Meng, Tingting; Ma, Haile; Zhang, Yanyan; Li, Yunliang; Jin, Jian; Ye, Xiaofei

    2016-09-01

    The mechanism of ultrasound field promoting enzymolysis efficiency is difficult to study, because the reaction system mixes with enzymes, proteins and hydrolysates. Immobilized enzyme is a good option that can be used to investigate the mechanism by separating enzymes out from the system after enzymolysis. The objective of this study was by using immobilized Alcalase to investigate the effects and mechanisms of the promotion of dual-frequency ultrasound (DFU) assisted-enzymolysis on rapeseed protein. Based on single factor experiments, response surface methodology model with three factors - hydrolysis time, power density and solid-liquid ratio at three levels was utilized to optimize the degree of hydrolysis (DH). Circular dichroism (CD) was used to analyze the secondary structure change of the protein, scanning electron microscopy (SEM) was used to analyze the surface microstructure change of the enzyme. The results showed that with DFU assisted-enzymolysis, the DH increased by 74.38% at the optimal levels for power density 57W/L, solid-liquid ratio 5.3g/L and enzymolysis time 76min. After DFU assisted-enzymolysis, the yield of soluble solids content, including protein, peptides and total sugar in hydrolysate increased by 64.61%, 40.88% and 23.60%, respectively. CD analysis showed that after DFU assisted-enzymolysis, the number of α-helix and random coil decreased by 10.7% and 4.5%, β-chain increased by 2.4%. SEM showed that the degree of surface roughness of immobilized Alcalase increased. The above results indicated that the improvement of hydrolysis by DFU assisted-enzymolysis was achieved by enhancing the solid solubility, changing the molecular structure of protein and increased the surface area of immobilized enzyme. PMID:27150775

  15. 34 CFR 76.760 - More than one program may assist a single activity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false More than one program may assist a single activity. 76... States and Subgrantees § 76.760 More than one program may assist a single activity. A State or a subgrantee may use funds under more than one program to support different parts of the same project if...

  16. 48 CFR Appendix F to Chapter 7 - Use of Collaborative Assistance Method for Title XII Activities

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Use of Collaborative Assistance Method for Title XII Activities F Appendix F to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Ch. 7, App. F Appendix F to Chapter 7—Use of Collaborative Assistance Method for Title XII Activities...

  17. COMPUTER-ASSISTED STUDIES OF MOLECULAR STRUCTURE-BIOLOGICAL ACTIVITY RELATIONSHIPS

    EPA Science Inventory

    Computer-assisted methods can be used to investigate the relationships between the molecular structures of compounds and their biological activity. A number of approaches have been reported in the literature, including correlations of activity with substituent constants, conforma...

  18. Electrophilic assistance to the cleavage of an RNA model phopshodiester via specific and general base-catalyzed mechanisms.

    PubMed

    Corona-Martínez, David Octavio; Gomez-Tagle, Paola; Yatsimirsky, Anatoly K

    2012-10-19

    Kinetics of transesterification of the RNA model substrate 2-hydroxypropyl 4-nitrophenyl phosphate promoted by Mg(2+) and Ca(2+), the most common biological metals acting as cofactors for nuclease enzymes and ribozymes, as well as by Co(NH(3))(6)(3+), Co(en)(3)(3+), Li(+), and Na(+) cations, often employed as mechanistic probes, was studied in 80% v/v (50 mol %) aqueous DMSO, a medium that allows one to discriminate easily specific base (OH(-)-catalyzed) and general base (buffer-catalyzed) reaction paths. All cations assist the specific base reaction, but only Mg(2+) and Na(+) assist the general base reaction. For Mg(2+)-assisted reactions, the solvent deuterium isotope effects are 1.23 and 0.25 for general base and specific base mechanisms, respectively. Rate constants for Mg(2+)-assisted general base reactions measured with different bases fit the Brønsted correlation with a slope of 0.38, significantly lower than the slope for the unassisted general base reaction (0.77). Transition state binding constants for catalysts in the specific base reaction (K(‡)(OH)) both in aqueous DMSO and pure water correlate with their binding constants to 4-nitrophenyl phosphate dianion (K(NPP)) used as a minimalist transition state model. It was found that K(‡)(OH) ≈ K(NPP) for "protic" catalysts (Co(NH(3))(6)(3+), Co(en)(3)(3+), guanidinium), but K(‡)(OH) ≫ K(NPP) for Mg(2+) and Ca(2+) acting as Lewis acids. It appears from results of this study that Mg(2+) is unique in its ability to assist efficiently the general base-catalyzed transesterification often occurring in active sites of nuclease enzymes and ribozymes. PMID:22991967

  19. [Stent-assisted mechanical removal of tromboembolism after embolization of middle cerebral artery aneurysm].

    PubMed

    Poncyljusz, Wojciech; Falkowski, Aleksander; Rać, Monika; Sagan, Leszek; Kojder, Ireneusz

    2012-01-01

    Thrombotic occlusion of the middle cerebral artery's branch occurred just after embolization of a nonruptured cerebral aneurysm. Bail-out stent-assisted mechanical thrombectomy of the clot was performed. DSA revealed normal vessel patency at the end of the procedure. There were no adverse events related to this thrombectomy, and the patient recovered from the embolization with minor neurologic deficit. There was no neurologic deficit after 90 days follow-up. PMID:23276015

  20. Thermo-mechanical modeling of the electrically-assisted manufacturing (EAM) technique during open die forging

    NASA Astrophysics Data System (ADS)

    Salandro, Wesley A.

    This thesis contains all of the steps which allow the Electrically-Assisted Manufacturing (EAM) technique to be experimentally explored and analytically modeled for an electrically-assisted forging operation. Chapter 1 includes the problem statement, proposed solution, and literature reviews on EAM. Chapter 2 describes a thorough background on the EAM technique, highlights prior EAM research, and explains the research approach taken for this thesis. The coupled thermo-mechanical modeling strategy, along with the introduction of the Electroplastic Effect Coefficient (EEC) is provided in Chapter 3. Chapter 4 explains the two different approaches to determine the EEC profiles when modeling a particular metal. The simplified EAF mechanical model for electrically-assisted forging is presented in Chapter 5. Also in this chapter, the same modeling methodology (i.e. thermo-mechanical, EEC, etc.) is used to predict loads for an electrically-assisted bending (EAB) process. The following chapters explore how different material- and process-based parameters affect the EAF technique. Chapter 6 examines how different workpiece contact areas affect EAF effectiveness, along with an exploration of how well different metal forming lubricants perform with EAF. Chapter 7 explores if there is a difference in the thermal or mechanical profiles of specimens undergoing EAF forging tests with different average grain sizes. Chapter 8 examines the same effects as the previous chapter on specimens with varying levels of prior cold work. The materials- and process-based simplifications and sensitivities of the proposed modeling strategy are outlined in Chapter 9. Chapters 10-14 include the science behind the electroplastic effect, conclusions, future work, broader impacts, and intellectual merit, respectively. The overall intention of this thesis is to show the candidate's ability to take an idea for a new manufacturing process, prove that it works, and then understand and model the process

  1. Molecular mechanisms regulating NLRP3 inflammasome activation

    PubMed Central

    Jo, Eun-Kyeong; Kim, Jin Kyung; Shin, Dong-Min; Sasakawa, Chihiro

    2016-01-01

    Inflammasomes are multi-protein signaling complexes that trigger the activation of inflammatory caspases and the maturation of interleukin-1β. Among various inflammasome complexes, the NLRP3 inflammasome is best characterized and has been linked with various human autoinflammatory and autoimmune diseases. Thus, the NLRP3 inflammasome may be a promising target for anti-inflammatory therapies. In this review, we summarize the current understanding of the mechanisms by which the NLRP3 inflammasome is activated in the cytosol. We also describe the binding partners of NLRP3 inflammasome complexes activating or inhibiting the inflammasome assembly. Our knowledge of the mechanisms regulating NLRP3 inflammasome signaling and how these influence inflammatory responses offers further insight into potential therapeutic strategies to treat inflammatory diseases associated with dysregulation of the NLRP3 inflammasome. PMID:26549800

  2. Mechanisms of Cell Propulsion by Active Stresses

    PubMed Central

    Carlsson, A. E.

    2011-01-01

    The mechanisms by which cytoskeletal flows and cell-substrate interactions interact to generate cell motion are explored using a simplified model of the cytoskeleton as a viscous gel containing active stresses. This model yields explicit general results relating cell speed and traction forces to the distributions of active stress and cell-substrate friction. It is found that 1) the cell velocity is given by a function that quantifies the asymmetry of the active-stress distribution, 2) gradients in cell-substrate friction can induce motion even when the active stresses are symmetrically distributed, 3) the traction-force dipole is enhanced by protrusive stresses near the cell edges or contractile stresses near the center of the cell, and 4) the cell velocity depends biphasically on the cell-substrate adhesion strength if active stress is enhanced by adhesion. Specific experimental tests of the calculated dependences are proposed. PMID:21804763

  3. Mechanisms of Cell Propulsion by Active Stresses.

    PubMed

    Carlsson, A E

    2011-07-01

    The mechanisms by which cytoskeletal flows and cell-substrate interactions interact to generate cell motion are explored using a simplified model of the cytoskeleton as a viscous gel containing active stresses. This model yields explicit general results relating cell speed and traction forces to the distributions of active stress and cell-substrate friction. It is found that 1) the cell velocity is given by a function that quantifies the asymmetry of the active-stress distribution, 2) gradients in cell-substrate friction can induce motion even when the active stresses are symmetrically distributed, 3) the traction-force dipole is enhanced by protrusive stresses near the cell edges or contractile stresses near the center of the cell, and 4) the cell velocity depends biphasically on the cell-substrate adhesion strength if active stress is enhanced by adhesion. Specific experimental tests of the calculated dependences are proposed. PMID:21804763

  4. Schottky Barrier Catalysis Mechanism in Metal-Assisted Chemical Etching of Silicon.

    PubMed

    Lai, Ruby A; Hymel, Thomas M; Narasimhan, Vijay K; Cui, Yi

    2016-04-13

    Metal-assisted chemical etching (MACE) is a versatile anisotropic etch for silicon although its mechanism is not well understood. Here we propose that the Schottky junction formed between metal and silicon plays an essential role on the distribution of holes in silicon injected from hydrogen peroxide. The proposed mechanism can be used to explain the dependence of the etching kinetics on the doping level, doping type, crystallographic surface direction, and etchant solution composition. We used the doping dependence of the reaction to fabricate a novel etch stop for the reaction. PMID:27018712

  5. Comets: mechanisms of x-ray activity

    NASA Astrophysics Data System (ADS)

    Ibadov, Subhon

    2016-07-01

    Basic mechanisms of X-ray activity of comets are considered, including D-D mechanism corresponding to generation of X-rays due to production of hot short-living plasma clumps at high-velocity collisions between cometary and interplanetary dust particles as well as M-M one corresponding to production of X-rays due to recombination of multicharge ions of solar wind plasma via charge exchange process at their collisions with molecules/atoms of the cometary atmospheres. Peculiarities of the variation of the comet X-ray spectrum and X-ray luminosity with variation of its heliocentric distance are revealed.

  6. Development of an assistive motorized hip orthosis: kinematics analysis and mechanical design.

    PubMed

    Olivier, Jeremy; Bouri, Mohamed; Ortlieb, Amalric; Bleuler, Hannes; Clavel, Reymond

    2013-06-01

    With the increase of life expectancy, a higher number of elderly need assistance to maintain their mobility and their independance. The hip joint is crucial for walking and is problematic for a large number of aged people. In this paper we present a novel design of a motorized hip orthosis to assist elderly people while walking, stair climbing and during the sit-to-stand transistions. The kinematics was developed based on biomechanics considerations. To be able to achieve a large assistance rate, velocity and torques of the hip joint were studied from the literature. In order to fit with these requirements, an amplification mechanism inspired by excavators was developed and implemented. Comfort considerations were also taken into account and a custom interface was designed with the collaboration of a professional orthopaedic technician. First tests with the prototype showed that the workspace is sufficient for walking, for stair climbing as well as for sit-to-stand transitions. The assistance rate can go up to 30% for a 70 kg subject during walking at a cadence of 100 steps/min. The comfort is guaranteed despite the important weight (4.3 kg) of this first prototype. PMID:24187310

  7. Catalog of organizations that assist inventors: Activities and services, Edition 2

    SciTech Connect

    Not Available

    1990-01-01

    Several different types of national, state, and local organizations and programs, both public and private, assist independent inventors. The number of such organizations and programs is growing. Most of them work independently of each other, often without knowledge of each other. The staff of the Energy-Related Inventions Program (ERIP) at the US Department of Energy (DOE) realized that: many of these organizations are quite capable of doing innovative things to assist inventors, and many have extensive, highly original programs aimed at organizing the inventor's social world; no mechanism has existed for these organizations to communicate with each other; evaluation of organizational success or failure in assisting inventors has been lacking; and some of these organizations could benefit from technical assistance and small amounts of financial assistance to encourage innovation in assisting inventors.

  8. [Molecular mechanisms of niclosamide antitumor activity].

    PubMed

    Moskaleva, E Yu; Perevozchikova, V G; Zhirnik, A S; Severin, S E

    2015-01-01

    In this review the recent data regarding the antitumor activity of niclosamide and the molecular mechanisms of its antitumor activity are presented. Niclosamide has been used in the clinic for the treatment of intestinal parasite infections. In recent years in several screening investigations of various drugs and chemical compounds niclosamide was identified as a potential anticancer agent. Niclosamide not only inhibits the Wnt/β-catenin, mTORC1, STAT3, NF-κB and Notch signaling pathways, but also targets mitochondria in cancer cells to induce growth inhibition and apoptosis. A number of studies have established the anticancer activity of niclosamide in both in vitro and in vivo in xenotransplantation models using human tumors and immunodeficient mice. It is important that niclosamide is active not only against tumor cells but also cancer stem cells. Normal cells are resistant to niclosamide. The accumulated experimental data suggest niclosamide is a promising drug for the treatment of various types of cancer. PMID:26716739

  9. Program activities, DOE state and local assistance programs, 1980 report

    SciTech Connect

    Chiogioji, Melvin H.

    1981-01-01

    Progress achieved by DOE State and Local Assistance Programs during FY 1980 and since they were established is summarized. These programs enable improved energy efficiency of industry, transportation, commercial establishments, public buildings, and residences. Eight programs (State Energy Conservation, Energy Extension Service, Weatherization Assistance, Institutional Buildings Grants, Energy-Related Inventions, Appropriate Technology Small Grants, Emergency Energy Conservation, Emergency Building Temperature Restrictions) are described. They provide the impetus for thousands of individual and organizational actions that have significantly affected national energy use patterns. (MCW)

  10. Efficient Catalytic Activity BiFeO3 Nanoparticles Prepared by Novel Microwave-Assisted Synthesis.

    PubMed

    Zou, Jing; Gong, Wanyun; Ma, Jinai; Li, Lu; Jiang, Jizhou

    2015-02-01

    A novel microwave-assisted sol-gel method was applied to the synthesis of the single-phase perovskite bismuth ferrite nanoparticles (BFO NPs) with the mean diameter ca. 73.7 nm. The morphology was characterized by scanning electron microscope (SEM). The X-ray diffraction (XRD) revealed the rhombohedral phase with R3c space group. The weak ferromagnetic behavior at room temperature was affirmed by the vibrating sample magnetometer (VSM). According to the UV-vis diffuse reflectance spectrum (UV-DSR), the band gap energy of BFO NPs was determined to be 2.18 eV. The electrochemical activity was evaluated by BFO NPs-chitosan-glassy carbon electrode (BFO-CS-GCE) sensor for detection of p-nitrophenol contaminants. The material showed an efficient oxidation catalytic activity by degrading methylene blue (MB). It was found that the degradation efficiency of 10 mg L-1 MB at pH 6.0 was above 90.9% after ultrasound- and microwave-combined-assisted (US-MW) irradiation for 15 min with BFO NPs as catalyst and H202 as oxidant. A possible reaction mechanism of degradation of MB was also proposed. PMID:26353647

  11. Neural Response During a Mechanically Assisted Spinal Manipulation in an Animal Model: A Pilot Study

    PubMed Central

    Reed, William R.; Liebschner, Michael A.K.; Sozio, Randall S.; Pickar, Joel G.; Gudavalli, Maruti R.

    2015-01-01

    Introduction Mechanoreceptor stimulation is theorized to contribute to the therapeutic efficacy of spinal manipulation. Use of mechanically-assisted spinal manipulation (MA-SM) devices is increasing among manual therapy clinicians worldwide. The purpose of this pilot study is to determine the feasibility of recording in vivo muscle spindle responses during a MA-SM in an intervertebral fixated animal model. Methods Intervertebral fixation was created by inserting facet screws through the left L5-6 and L6-7 facet joints of a cat spine. Three L6muscle spindle afferents with receptive fields in back muscles were isolated. Recordings were made during MA-SM thrusts delivered to the L7 spinous process using an instrumented Activator IV clinical device. Results Nine MA-SM thrusts were delivered with peak forces ranging from 68-122N and with thrust durations of less than 5ms. High frequency muscle spindle discharge occurred during MA-SM. Following the MA-SM, muscle spindle responses included returning to pre-manipulation levels, slightly decreasing for a short window of time, and greatly decreasing for more than 40s. Conclusion This study demonstrates that recording in vivo muscle spindle response using clinical MA-SM devices in an animal model is feasible. Extremely short duration MA-SM thrusts (<5ms) can have an immediate and/or a prolonged (> 40s) effect on muscle spindle discharge. Greater peak forces during MA-SM thrusts may not necessarily yield greater muscle spindle responses. Determining peripheral response during and following spinal manipulation may be an important step in optimizing its’ clinical efficacy. Future studies may investigate the effect of thrust dosage and magnitude. PMID:26618202

  12. Assisted Ventilation.

    PubMed

    Dries, David J

    2016-01-01

    Controlled Mechanical Ventilation may be essential in the setting of severe respiratory failure but consequences to the patient including increased use of sedation and neuromuscular blockade may contribute to delirium, atelectasis, and diaphragm dysfunction. Assisted ventilation allows spontaneous breathing activity to restore physiological displacement of the diaphragm and recruit better perfused lung regions. Pressure Support Ventilation is the most frequently used mode of assisted mechanical ventilation. However, this mode continues to provide a monotonous pattern of support for respiration which is normally a dynamic process. Noisy Pressure Support Ventilation where tidal volume is varied randomly by the ventilator may improve ventilation and perfusion matching but the degree of support is still determined by the ventilator. Two more recent modes of ventilation, Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist (NAVA), allow patient determination of the pattern and depth of ventilation. Proposed advantages of Proportional Assist Ventilation and NAVA include decrease in patient ventilator asynchrony and improved adaptation of ventilator support to changing patient demand. Work of breathing can be normalized with these modes as well. To date, however, a clear pattern of clinical benefit has not been demonstrated. Existing challenges for both of the newer assist modes include monitoring patients with dynamic hyperinflation (auto-positive end expiratory pressure), obstructive lung disease, and air leaks in the ventilator system. NAVA is dependent on consistent transduction of diaphragm activity by an electrode system placed in the esophagus. Longevity of effective support with this technique is unclear. PMID:25501776

  13. Topological mechanics: from metamaterials to active matter

    NASA Astrophysics Data System (ADS)

    Vitelli, Vincenzo

    2015-03-01

    Mechanical metamaterials are artificial structures with unusual properties, such as negative Poisson ratio, bistability or tunable acoustic response, which originate in the geometry of their unit cell. At the heart of such unusual behavior is often a mechanism: a motion that does not significantly stretch or compress the links between constituent elements. When activated by motors or external fields, these soft motions become the building blocks of robots and smart materials. In this talk, we discuss topological mechanisms that possess two key properties: (i) their existence cannot be traced to a local imbalance between degrees of freedom and constraints (ii) they are robust against a wide range of structural deformations or changes in material parameters. The continuum elasticity of these mechanical structures is captured by non-linear field theories with a topological boundary term similar to topological insulators and quantum Hall systems. We present several applications of these concepts to the design and experimental realization of 2D and 3D topological structures based on linkages, origami, buckling meta-materials and lastly active media that break time-reversal symmetry.

  14. Mechanically activated artificial cell by using microfluidics.

    PubMed

    Ho, Kenneth K Y; Lee, Lap Man; Liu, Allen P

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology. PMID:27610921

  15. Mechanically activated artificial cell by using microfluidics

    PubMed Central

    Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology. PMID:27610921

  16. Cellular Mechanisms Controlling Caspase Activation and Function

    PubMed Central

    Parrish, Amanda B.; Freel, Christopher D.; Kornbluth, Sally

    2013-01-01

    Caspases are the primary drivers of apoptotic cell death, cleaving cellular proteins that are critical for dismantling the dying cell. Initially translated as inactive zymogenic precursors, caspases are activated in response to a variety of cell death stimuli. In addition to factors required for their direct activation (e.g., dimerizing adaptor proteins in the case of initiator caspases that lie at the apex of apoptotic signaling cascades), caspases are regulated by a variety of cellular factors in a myriad of physiological and pathological settings. For example, caspases may be modified posttranslationally (e.g., by phosphorylation or ubiquitylation) or through interaction of modulatory factors with either the zymogenic or active form of a caspase, altering its activation and/or activity. These regulatory events may inhibit or enhance enzymatic activity or may affect activity toward particular cellular substrates. Finally, there is emerging literature to suggest that caspases can participate in a variety of cellular processes unrelated to apoptotic cell death. In these settings, it is particularly important that caspases are maintained under stringent control to avoid inadvertent cell death. It is likely that continued examination of these processes will reveal new mechanisms of caspase regulation with implications well beyond control of apoptotic cell death. PMID:23732469

  17. Beyond the VAD: Human Factors Engineering for Mechanically Assisted Circulation in the 21st Century.

    PubMed

    Throckmorton, Amy L; Patel-Raman, Sonna M; Fox, Carson S; Bass, Ellen J

    2016-06-01

    Thousands of ventricular assist devices (VADs) currently provide circulatory support to patients worldwide, and dozens of heart pump designs for adults and pediatric patients are under various stages of development in preparation for translation to clinical use. The successful bench-to-bedside development of a VAD involves a structured evaluation of possible system states, including human interaction with the device and auxiliary component usage in the hospital or home environment. In this study, we review the literature and present the current landscape of preclinical design and assessment, decision support tools and procedures, and patient-centered therapy. Gaps of knowledge are identified. The study findings support the need for more attention to user-centered design approaches for medical devices, such as mechanical circulatory assist systems, that specifically involve detailed qualitative and quantitative assessments of human-device interaction to mitigate risk and failure. PMID:26511100

  18. Curriculum Development of Learning Activity Packets, Dental Assisting Program. Final Report.

    ERIC Educational Resources Information Center

    Hempler, Nancy A.

    A dental assisting instructor was provided with 250 hours of released time to develop standardized Learning Activity Packets (LAPs) for the Dental Assisting program at the Bellingham (Washington) Vocational Technical Institute. The instructor reviewed unit objectives, gathered input from local dental professionals, reviewed reference materials,…

  19. 24 CFR 570.210 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Prohibition on use of assistance for employment relocation activities. 570.210 Section 570.210 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR...

  20. 24 CFR 570.210 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 3 2011-04-01 2010-04-01 true Prohibition on use of assistance for employment relocation activities. 570.210 Section 570.210 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING...

  1. 75 FR 33636 - Bureau of Justice Assistance; Agency Information Collection Activities: Proposed Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Office of Justice Programs Bureau of Justice Assistance; Agency Information Collection Activities: Proposed Collection Comments Requested ACTION: 30-Day Notice of Information Collection Under Review: New Collection Bureau of Justice Assistance...

  2. Health Occupations--Nursing Assistant, Wheelchair. Kit No. 58. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Brown, Annie T.

    An instructor's manual and student activity guide on the nursing assistant--assisting patients in using the wheelchair are provided in this set of prevocational education materials which focuses on the vocational area of health occupations. (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven…

  3. 24 CFR 570.210 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 3 2014-04-01 2013-04-01 true Prohibition on use of assistance for employment relocation activities. 570.210 Section 570.210 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING...

  4. 24 CFR 570.210 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 3 2013-04-01 2013-04-01 false Prohibition on use of assistance for employment relocation activities. 570.210 Section 570.210 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR...

  5. 24 CFR 1003.209 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Prohibition on use of assistance for employment relocation activities. 1003.209 Section 1003.209 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC...

  6. 24 CFR 570.210 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 3 2012-04-01 2012-04-01 false Prohibition on use of assistance for employment relocation activities. 570.210 Section 570.210 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR...

  7. 24 CFR 1003.209 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Prohibition on use of assistance for employment relocation activities. 1003.209 Section 1003.209 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC AND INDIAN HOUSING, DEPARTMENT OF HOUSING AND...

  8. 24 CFR 1003.209 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Prohibition on use of assistance for employment relocation activities. 1003.209 Section 1003.209 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC...

  9. 24 CFR 1003.209 - Prohibition on use of assistance for employment relocation activities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Prohibition on use of assistance for employment relocation activities. 1003.209 Section 1003.209 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC...

  10. Mechanism of FGF receptor dimerization and activation.

    PubMed

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise. PMID:26725515

  11. Mechanism of FGF receptor dimerization and activation

    NASA Astrophysics Data System (ADS)

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise.

  12. Mechanism of FGF receptor dimerization and activation

    PubMed Central

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise. PMID:26725515

  13. Improvement of mechanical properties by additive assisted laser sintering of PEEK

    SciTech Connect

    Kroh, M. Bonten, C.; Eyerer, P.

    2014-05-15

    The additive assisted laser sintering was recently developed at IKT: A carbon black (CB) additive is used to adjust the polymer's laser absorption behavior with the aim to improve the interconnection of sintered powder layers. In this paper a parameter study, Polyetheretherketone (PEEK) samples were prepared with different contents of carbon black and were laser sintered with varying thermal treatment. The samples were mechanically tested and investigated by optical light and transmission electron microscopy. An influence on the morphology at the border areas of particles and intersections of laser sintered layers was found. Depending on the viscosity of the raw material and CB content, different shapes of lamellae were observed. These (trans-) crystalline or polymorph structures, respectively, influence the thermal and mechanical behavior of the virgin PEEK. Moreover, the thermal treatment during the sintering process caused an improvement of mechanical properties like tensile strength and elongation at break.

  14. Shaping Neuronal Network Activity by Presynaptic Mechanisms

    PubMed Central

    Ashery, Uri

    2015-01-01

    Neuronal microcircuits generate oscillatory activity, which has been linked to basic functions such as sleep, learning and sensorimotor gating. Although synaptic release processes are well known for their ability to shape the interaction between neurons in microcircuits, most computational models do not simulate the synaptic transmission process directly and hence cannot explain how changes in synaptic parameters alter neuronal network activity. In this paper, we present a novel neuronal network model that incorporates presynaptic release mechanisms, such as vesicle pool dynamics and calcium-dependent release probability, to model the spontaneous activity of neuronal networks. The model, which is based on modified leaky integrate-and-fire neurons, generates spontaneous network activity patterns, which are similar to experimental data and robust under changes in the model's primary gain parameters such as excitatory postsynaptic potential and connectivity ratio. Furthermore, it reliably recreates experimental findings and provides mechanistic explanations for data obtained from microelectrode array recordings, such as network burst termination and the effects of pharmacological and genetic manipulations. The model demonstrates how elevated asynchronous release, but not spontaneous release, synchronizes neuronal network activity and reveals that asynchronous release enhances utilization of the recycling vesicle pool to induce the network effect. The model further predicts a positive correlation between vesicle priming at the single-neuron level and burst frequency at the network level; this prediction is supported by experimental findings. Thus, the model is utilized to reveal how synaptic release processes at the neuronal level govern activity patterns and synchronization at the network level. PMID:26372048

  15. Biomolecule-assisted construction of cadmium sulfide hollow spheres with structure-dependent photocatalytic activity.

    PubMed

    Wei, Chengzhen; Zang, Wenzhe; Yin, Jingzhou; Lu, Qingyi; Chen, Qun; Liu, Rongmei; Gao, Feng

    2013-02-25

    In this study, we report the synthesis of monodispersive solid and hollow CdS spheres with structure-dependent photocatalytic abilities for dye photodegradation. The monodispersive CdS nanospheres were constructed with the assistance of the soulcarboxymthyi chitosan biopolymer under hydrothermal conditions. The solid CdS spheres were corroded by ammonia to form hollow CdS nanospheres through a dissolution-reprecipitation mechanism. Their visible-light photocatalytic activities were investigated, and the results show that both the solid and the hollow CdS spheres have visible-light photocatalytic abilities for the photodegradation of dyes. The photocatalytic properties of the CdS spheres were demonstrated to be structure dependent. Although the nanoparticles comprising the hollow spheres have larger sizes than those comprising the solid spheres, the hollow CdS spheres have better photocatalytic performances than the solid CdS spheres, which can be attributed to the special hollow structure. PMID:23297031

  16. Micro-emulsion-assisted synthesis of ZnS nanospheres and their photocatalytic activity

    SciTech Connect

    Li Yao; He Xiaoyan; Cao Minhua

    2008-11-03

    ZnS nanospheres with rough surface were synthesized by using a micro-emulsion-assisted solvothemal process. The molar ratio of [water]/[surfactant] played an important role in controlling the size of the ZnS nanospheres. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), field emission-scanning electron microscope (FE-SEM), and selected area electron diffraction (SAED) were used for the characterization of the resulting ZnS nanospheres. A possible formation mechanism was proposed. These ZnS nanospheres exhibited a good photocatalytic activity for degradation of an aqueous p-nitrophenol solution and the total organic carbon (TOC) of the degradation product has also been investigated.

  17. A Consulting System Assisting Naive Users In Decomposing And Constructing A Mechanical Object

    NASA Astrophysics Data System (ADS)

    Abe, Norihiro; Tsuji, Saburo

    1984-06-01

    A new consulting system using a natural language and a graphical interface is under construction to assist a naive user in decomposing and constructing a mechanical object with cylindrical bodies. Many trouble shooting systems have been developed so far, but most of them do not tell us the way for decomposing the object to find out trouble points. This system is built to assist naive user in decomposing a mechanical object and in constructing it after repairation. It is difficult for a computer to give him a series of operations necessary for exposing a trouble point by using just simple command suquences, then an integrated instruction facility using a natural language and a visual interface must be offered to users for specifying what portion of the object should be decomposed or constructed at the next stage, and for verifying whether what the user have done to the object is correct or incorrect. The present art of computer vision cannot verify if an act taken by the user is correct or not at each step, because mechanical objects sometimes have involved structures. This system leaves this verification process to the user by showing him two perspective views of the objects, and an explanation on the operation which causes these two views before and after decomposition or construction.

  18. Activities of the Institute for Mechanical Engineering

    NASA Astrophysics Data System (ADS)

    The Institute of Mechanical Engineering (IME) is part of Canada's National Research Council. Its mission is to undertake, support, promote, and disseminate research and development in the mechanical engineering aspects of three vital sectors of the Canadian economy: transportation, resource industries, and manufacturing. The IME achieves its mission by performing research and development in its own facilities; by developing, providing, and transferring expertise and knowledge; by making its research facilities available to collaborators and clients; and by participating in international liaison and collaborative research activities. Six research programs are conducted in the IME: Advanced Manufacturing Technology; Coastal Zone Engineering; Cold Regions Engineering; Combustion and Fluids Engineering; Ground Transportation Technology; and Machinery and Engine Technology. The rationale and major research thrusts of each program are described, and specific achievements in 1991-92 are reviewed. Lists of technical reports and papers presented by IME personnel are also included.

  19. Molecular mechanisms of asymmetric RAF dimer activation.

    PubMed

    Jambrina, Pablo G; Bohuszewicz, Olga; Buchete, Nicolae-Viorel; Kolch, Walter; Rosta, Edina

    2014-08-01

    Protein phosphorylation is one of the most common post-translational modifications in cell regulatory mechanisms. Dimerization plays also a crucial role in the kinase activity of many kinases, including RAF, CDK2 (cyclin-dependent kinase 2) and EGFR (epidermal growth factor receptor), with heterodimers often being the most active forms. However, the structural and mechanistic details of how phosphorylation affects the activity of homo- and hetero-dimers are largely unknown. Experimentally, synthesizing protein samples with fully specified and homogeneous phosphorylation states remains a challenge for structural biology and biochemical studies. Typically, multiple changes in phosphorylation lead to activation of the same protein, which makes structural determination methods particularly difficult. It is also not well understood how the occurrence of phosphorylation and dimerization processes synergize to affect kinase activities. In the present article, we review available structural data and discuss how MD simulations can be used to model conformational transitions of RAF kinase dimers, in both their phosphorylated and unphosphorylated forms. PMID:25109958

  20. Similarity between the primary and secondary air-assisted liquid jet breakup mechanisms.

    PubMed

    Wang, Yujie; Im, Kyoung-Su; Fezzaa, Kamel

    2008-04-18

    We report an ultrafast synchrotron x-ray phase-contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. There exist great similarities between the primary (jet) and the secondary (drop) breakup, and in the primary breakup on different length scales. A transition from a ligament- to a membrane-mediated breakup is identified around an effective Weber number We' approximately 13. This observation reveals the critical role an effective Weber number plays in determining the atomization process and strongly supports the cascade breakup model. PMID:18518113

  1. Mechanical Modulation of Phonon-Assisted Field Emission in a Silicon Nanomembrane Detector for Time-of-Flight Mass Spectrometry.

    PubMed

    Park, Jonghoo; Blick, Robert H

    2016-01-01

    We demonstrate mechanical modulation of phonon-assisted field emission in a free-standing silicon nanomembrane detector for time-of-flight mass spectrometry of proteins. The impacts of ion bombardment on the silicon nanomembrane have been explored in both mechanical and electrical points of view. Locally elevated lattice temperature in the silicon nanomembrane, resulting from the transduction of ion kinetic energy into thermal energy through the ion bombardment, induces not only phonon-assisted field emission but also a mechanical vibration in the silicon nanomembrane. The coupling of these mechanical and electrical phenomenon leads to mechanical modulation of phonon-assisted field emission. The thermal energy relaxation through mechanical vibration in addition to the lateral heat conduction and field emission in the silicon nanomembrane offers effective cooling of the nanomembrane, thereby allowing high resolution mass analysis. PMID:26861329

  2. Mechanical Modulation of Phonon-Assisted Field Emission in a Silicon Nanomembrane Detector for Time-of-Flight Mass Spectrometry

    PubMed Central

    Park, Jonghoo; Blick, Robert H.

    2016-01-01

    We demonstrate mechanical modulation of phonon-assisted field emission in a free-standing silicon nanomembrane detector for time-of-flight mass spectrometry of proteins. The impacts of ion bombardment on the silicon nanomembrane have been explored in both mechanical and electrical points of view. Locally elevated lattice temperature in the silicon nanomembrane, resulting from the transduction of ion kinetic energy into thermal energy through the ion bombardment, induces not only phonon-assisted field emission but also a mechanical vibration in the silicon nanomembrane. The coupling of these mechanical and electrical phenomenon leads to mechanical modulation of phonon-assisted field emission. The thermal energy relaxation through mechanical vibration in addition to the lateral heat conduction and field emission in the silicon nanomembrane offers effective cooling of the nanomembrane, thereby allowing high resolution mass analysis. PMID:26861329

  3. Mechanism on microwave-assisted acidic solvolysis of black-liquor lignin.

    PubMed

    Dong, Chengjian; Feng, Chunguang; Liu, Qian; Shen, Dekui; Xiao, Rui

    2014-06-01

    Microwave-assisted degradation of black-liquor lignin with formic acid was studied, concerning the product yield and distribution of phenolic compounds against reaction temperature (110-180°C) and reaction time (5-90 min). The liquid product consisting of bio-oil 1 and bio-oil 2, achieved the maxima yield of 64.08% at 160°C and 30 min (bio-oil 1: 9.69% and bio-oil 2: 54.39%). The chemical information of bio-oil 1 and bio-oil 2 were respectively identified by means of Gas Chromatography-Mass Spectrometer (GC-MS) and Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), while the solid residue was analyzed by Gel Permeation Chromatography (GPC) and Fourier Transform Infrared Spectroscopy (FTIR). A possible mechanism was proposed for the microwave-assisted acidic solvolysis of lignin, specifying the kinetic relationship among the primary cracking of lignin, repolymerization of the oligomers and formation of solid residue. PMID:24747392

  4. Vessel wall perforation mechanism of the excimer laser-assisted non-occlusive anastomosis technique.

    PubMed

    Bremmer, Jochem; van Doormaal, Tristan P C; Verweij, Bon H; van der Zwan, Albert; Tulleken, Cornelius A F; Verdaasdonk, Rudolf

    2016-08-01

    The excimer laser assisted non-occlusive anastomosis (ELANA) technique is used to make anastomoses on intracerebral arteries. This end-to-side anastomosis is created without temporary occlusion of the recipient artery using a 308-nm excimer laser with a ring-shaped multi-fiber catheter to punch an opening in the arterial wall. Over 500 patients have received an ELANA bypass. However, the vessel wall perforation mechanism of the laser catheter is not known exactly and not 100 % successful. In this study, we aimed to understand the mechanism of ELANA vessel perforation using specialized imaging techniques to ultimately improve its effectiveness. High-speed imaging, high-contrast imaging, and high-sensitivity thermal imaging were used to study the laser wall perforation mechanism and reveal the mechanical and thermal effects involved. In vitro, rabbit arteries were exposed with the special designed laser catheter in a setup representative for the clinical setting, in which blood was replaced with a transparent UV absorbing liquid for visualization. We observed that laser vessel wall perforation was caused by explosive vapor bubbles tearing through the vessel wall, mostly within the first 20 of the total 200 pulses. Thermal effects were minimal. Unsymmetrical tension in the vessel wall inducing migration of the flap during laser exposure was observed in case of unsuccessful wall perforations. The laser wall perforation mechanism in the ELANA technique is primarily mechanical. Symmetric tension in the recipient vessel wall is essential and should be trained by neurosurgeons. PMID:27220531

  5. Mechanism and active variety of allelochemicals

    USGS Publications Warehouse

    Peng, S.-L.; Wen, J.; Guo, Q.-F.

    2004-01-01

    This article summarizes allelochemicals' active variety, its potential causes and function mechanisms. Allelochemicals' activity varies with temperature, photoperiod, water and soils during natural processes, with its initial concentration, compound structure and mixed degree during functional processes, with plant accessions, tissues and maturity within-species, and with research techniques and operation processes. The prospective developmental aspects of allelopathy studies in the future are discussed. Future research should focus on: (1) to identify and purify allelochemicals more effectively, especially for agriculture, (2) the functions of allelopathy at the molecular structure level, (3) using allelopathy to explain plant species interactions, (4) allelopathy as a driving force of succession, and (5) the significance of allelopathy in the evolutionary processes.

  6. Mechanical insufflation-exsufflation. Comparison of peak expiratory flows with manually assisted and unassisted coughing techniques.

    PubMed

    Bach, J R

    1993-11-01

    Pulmonary complications are major causes of morbidity and mortality for patients with severe expiratory muscle weakness. The purpose of this study was to compare peak cough expiratory flows (PCEFs) during unassisted and assisted coughing and review the long-term use of mechanical insufflation-exsufflation (MI-E) for 46 neuromuscular ventilator users. These individuals used noninvasive methods of ventilatory support for a mean of 21.1 h/d for 17.3 +/- 15.5 years. They relied on manually assisted coughing and/or MI-E during periods of productive airway secretion. They reported a mean of 0.7 +/- 1.2 cases of pneumonia and other serious pulmonary complications and 2.8 +/- 5.6 hospitalizations during the 16.4-year period and no complications of MI-E. A sample of 21 of these patients with a mean forced vital capacity of 490 +/- 370 ml had a mean maximum insufflation capacity (MIC) achieved by a combination of air stacking of ventilator insufflations and glossopharyngeal breathing of 1,670 +/- 540 ml. The PCEFs for this sample were: following an unassisted inspiration, 1.81 +/- 1.03 L/s; following a MIC maneuver, 3.37 +/- 1.07 L/s; with manual assistance by abdominal compression following a MIC maneuver, 4.27 +/- 1.29 L/s; and with MI-E, 7.47 +/- 1.02 L/s. Each PCEF was significantly greater than the preceding, respectively (p < 0.01). We conclude that manually assisted coughing and MI-E are effective and safe methods for facilitating airway secretion clearance for neuromuscular ventilator users who would otherwise be managed by endotracheal suctioning. Severely decreased MIC, but not necessarily vital capacity, is an indication for tracheostomy. PMID:8222823

  7. Engineering Knowledge for Assistive Living

    NASA Astrophysics Data System (ADS)

    Chen, Liming; Nugent, Chris

    This paper introduces a knowledge based approach to assistive living in smart homes. It proposes a system architecture that makes use of knowledge in the lifecycle of assistive living. The paper describes ontology based knowledge engineering practices and discusses mechanisms for exploiting knowledge for activity recognition and assistance. It presents system implementation and experiments, and discusses initial results.

  8. Mechanism for accurate, protein-assisted DNA annealing by Deinococcus radiodurans DdrB.

    PubMed

    Sugiman-Marangos, Seiji N; Weiss, Yoni M; Junop, Murray S

    2016-04-19

    Accurate pairing of DNA strands is essential for repair of DNA double-strand breaks (DSBs). How cells achieve accurate annealing when large regions of single-strand DNA are unpaired has remained unclear despite many efforts focused on understanding proteins, which mediate this process. Here we report the crystal structure of a single-strand annealing protein [DdrB (DNA damage response B)] in complex with a partially annealed DNA intermediate to 2.2 Å. This structure and supporting biochemical data reveal a mechanism for accurate annealing involving DdrB-mediated proofreading of strand complementarity. DdrB promotes high-fidelity annealing by constraining specific bases from unauthorized association and only releases annealed duplex when bound strands are fully complementary. To our knowledge, this mechanism provides the first understanding for how cells achieve accurate, protein-assisted strand annealing under biological conditions that would otherwise favor misannealing. PMID:27044084

  9. Etching anisotropy mechanisms lead to morphology-controlled silicon nanoporous structures by metal assisted chemical etching.

    PubMed

    Jiang, Bing; Li, Meicheng; Liang, Yu; Bai, Yang; Song, Dandan; Li, Yingfeng; Luo, Jian

    2016-02-01

    The etching anisotropy induced by the morphology and rotation of silver particles controls the morphology of silicon nanoporous structures, through various underlying complex etching mechanisms. The level of etching anisotropy can be modulated by controlling the morphology of the silver catalyst to obtain silicon nanoporous structures with straight pores, cone-shaped pores and pyramid-shaped pores. In addition, the structures with helical pores are obtained by taking advantage of the special anisotropic etching, which is induced by the rotation and revolution of silver particles during the etching process. An investigation of the etching anisotropy during metal assisted chemical etching will promote a deep understanding of the chemical etching mechanism of silicon, and provide a feasible approach to fabricate Si nanoporous structures with special morphologies. PMID:26785718

  10. Mechanical properties of silicon oxynitride thin films prepared by low energy ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Shima, Yukari; Hasuyama, Hiroki; Kondoh, Toshiharu; Imaoka, Yasuo; Watari, Takanori; Baba, Koumei; Hatada, Ruriko

    1999-01-01

    Silicon oxynitride (SiO xN y) films (0.1-0.7 μm) were produced on Si (1 0 0), glass and 316L stainless steel substrates by ion beam assisted deposition (IBAD) using Si evaporation and the concurrent bombardment with a mixture of 200 eV N 2 and Ar, or O 2 and Ar ions. Adhesion was evaluated by pull-off tests. Film hardness was measured by a nanoindentation system with AFM. The measurement of internal stress in the films was carried out by the Stoney method. The film structure was examined by GXRD. XPS was employed to measure the composition of films and to analyze the chemical bonds. The dependence of mechanical properties on the film thickness and the processing temperature during deposition was studied. Finally, the relations between the mechanical properties of the films and the correlation with corrosion-protection ability of films are discussed and summarized.

  11. Mechanical circulatory assist devices: a primer for critical care and emergency physicians.

    PubMed

    Sen, Ayan; Larson, Joel S; Kashani, Kianoush B; Libricz, Stacy L; Patel, Bhavesh M; Guru, Pramod K; Alwardt, Cory M; Pajaro, Octavio; Farmer, J Christopher

    2016-01-01

    Mechanical circulatory assist devices are now commonly used in the treatment of severe heart failure as bridges to cardiac transplant, as destination therapy for patients who are not transplant candidates, and as bridges to recovery and "decision-making". These devices, which can be used to support the left or right ventricles or both, restore circulation to the tissues, thereby improving organ function. Left ventricular assist devices (LVADs) are the most common support devices. To care for patients with these devices, health care providers in emergency departments (EDs) and intensive care units (ICUs) need to understand the physiology of the devices, the vocabulary of mechanical support, the types of complications patients may have, diagnostic techniques, and decision-making regarding treatment. Patients with LVADs who come to the ED or are admitted to the ICU usually have nonspecific clinical symptoms, most commonly shortness of breath, hypotension, anemia, chest pain, syncope, hemoptysis, gastrointestinal bleeding, jaundice, fever, oliguria and hematuria, altered mental status, headache, seizure, and back pain. Other patients are seen for cardiac arrest, psychiatric issues, sequelae of noncardiac surgery, and trauma. Although most patients have LVADs, some may have biventricular support devices or total artificial hearts. Involving a team of cardiac surgeons, perfusion experts, and heart-failure physicians, as well as ED and ICU physicians and nurses, is critical for managing treatment for these patients and for successful outcomes. This review is designed for critical care providers who may be the first to see these patients in the ED or ICU. PMID:27342573

  12. Active ageing: independence through technology assisted health optimisation.

    PubMed

    Manning, B R M; McCann, J; Benton, S; Bougourd, J

    2008-01-01

    The potential doubling in the percentage of the elderly within the populations of Europe and beyond over the next decades has focused informatics research on the development Assistive Technologies and Smart Homes. However its concentration on creating a supportive home environment also has the potential for makings its users over dependent on its facilities and as a result trapped within it. This paper outlines an approach that extends the smart homes concept out into the wider community to create a smart environment that not only maintains contact with all their home-based services, but also expands these to include other facilities needed to assist them whilst on the move. This involves the convergence of physiological monitoring, communications and computing with leading-edge textile technologies, which uses a multi-layered, multi-functional clothing system as a mobile and extended variant of a smart home IP hub. In addition to variable functionality capabilities of the clothing layers in terms of thermal, shock-absorbent and other characteristics, wireless IP connectivity is provided between layers with external links typically being WiFi enabled. Health optimisation is provided by on-going lifestyle guidance/action feedback based on auto-diagnostic analysis. PMID:18560086

  13. Exoskeleton control for lower-extremity assistance based on adaptive frequency oscillators: adaptation of muscle activation and movement frequency.

    PubMed

    Aguirre-Ollinger, Gabriel

    2015-01-01

    In this article, we analyze a novel strategy for assisting the lower extremities based on adaptive frequency oscillators. Our aim is to use the control algorithm presented here as a building block for the control of powered lower-limb exoskeletons. The algorithm assists cyclic movements of the human extremities by synchronizing actuator torques with the estimated net torque exerted by the muscles. Synchronization is produced by a nonlinear dynamical system combining an adaptive frequency oscillator with a form of adaptive Fourier analysis. The system extracts, in real time, the fundamental frequency component of the net muscle torque acting on a specific joint. Said component, nearly sinusoidal in shape, is the basis for the assistive torque waveform delivered by the exoskeleton. The action of the exoskeleton can be interpreted as a virtual reduction in the mechanical impedance of the leg. We studied the ability of human subjects to adapt their muscle activation to the assistive torque. Ten subjects swung their extended leg while coupled to a stationary hip joint exoskeleton. The experiment yielded a significant decrease, with respect to unassisted movement, of the activation levels of an agonist/antagonist pair of muscles controlling the hip joint's motion, which suggests the exoskeleton control has potential for assisting human gait. A moderate increase in swing frequency was observed as well. We theorize that the increase in frequency can be explained by the impedance model of the assisted leg. Per this model, subjects adjust their swing frequency in order to control the amount of reduction in net muscle torque. PMID:25655955

  14. Outcomes of patients implanted with a left ventricular assist device at nontransplant mechanical circulatory support centers.

    PubMed

    Katz, Marc R; Dickinson, Michael G; Raval, Nirav Y; Slater, James P; Dean, David A; Zeevi, Gary R; Horn, Evelyn M; Salemi, Arash

    2015-05-01

    The goal of this study was to assess outcomes of patients who underwent implantation of left ventricular assist devices (LVADs) at nontransplantation mechanical circulatory support centers. As the availability of LVADs for advanced heart failure has expanded to nontransplantation mechanical circulatory support centers, concerns have been expressed about maintaining good outcomes. Demographics and outcomes were evaluated in 276 patients with advanced heart failure who underwent implantation of LVADs as bridge to transplantation or destination therapy at 27 open-heart centers. Baseline characteristics, operative mortality, length of stay, readmission rate, adverse events, quality of life, and survival were analyzed. The overall 30-day mortality was 3% (8 of 276), and survival rates at 6, 12, and 24 months, respectively, were 92±2%, 88±3%, and 84±4% for the bridge-to-transplantation group and 81±3%, 70±5%, and 63±6% for the destination therapy group, comparable with results published by the national Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). The median length of stay for all patients was 21 days. Bleeding was the most frequent adverse event. Stroke occurred in 4% (bridge to transplantation) and 6% (destination therapy) of patients. Quality-of-life measures and 6-minute walk distances showed sustained improvements throughout support. In conclusion, outcomes with LVAD support at open-heart centers are acceptable and comparable with results from the INTERMACS registry. With appropriate teams, training, center commitment, and certification, LVAD therapy is being disseminated in a responsible way to open-heart centers. PMID:25772738

  15. Mechanism study on the effects of side assisting gas velocity during CO{sub 2} laser welding process

    SciTech Connect

    Zhang Linjie; Zhang Jianxun; Gong Shuili

    2009-07-15

    An experimental study on the effects of side assisting gas during CO{sub 2} laser welding has been carried out, and it is found that side assisting gas velocity can significantly affect the laser induced plasma and the weld cross-sectional geometry. In order to get better understanding on the associated mechanism, a three dimensional model based on the conservation laws of mass, momentum, and energy has been developed to simulate the spatial distributions of plasma temperature under different side assisting gas velocities. Furthermore, ray-tracing method is employed to investigate the variation of bremsstrahlung absorption and power density distribution on keyhole walls at different side assisting gas velocities with the assumption of conical keyhole shape. The results show that the diminishing of refraction and bremsstrahlung absorption due to an increase in side assisting gas velocity results in an increase in heat transfer efficiency, which contributes to the increase of weld cross-sectional area and penetration depth.

  16. Use of general purpose mechanical computer assisted engineering software in orthopaedic surgical planning: advantages and limitations.

    PubMed

    Sutherland, C J; Bresina, S J; Gayou, D E

    1994-01-01

    Two surgical plans were developed for an appropriately complex reconstructive orthopaedic surgery case. One plan was developed with customary methods using two-dimensional (2D) radiographs. The second plan was developed with general purpose mechanical computer assisted engineering (MCAE) software using x-ray computed tomography (CT) data. The limitations of each method are identified. To create a surgical plan using three-dimensional (3D) medical datasets and MCAE software, five necessary steps were identified: (a) data reduction; (b) contour extraction; (c) 3D model creation; (d) extraction of mass properties; (e) model idealization. The principal limitation of general purpose MCAE software is the lack of pre-processing modules with which to address the unique requirements of medical image datasets. PMID:7850738

  17. The mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water

    NASA Astrophysics Data System (ADS)

    Yu, Zhuanni; Chen, Xiaolin; Xia, Shuwei

    2016-06-01

    In this paper, the total sugar concentration, protein concentration, lipid yield and morphology characteristics of the algae residue were determined to explain the mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water. The results showed similar variation for the sugar, protein and lipid. However, the total sugar was more similar to lipids yield, so the results showed that the reaction between ionic liquid and cellulose and hemicellulose in cell wall was the most important step which determined the lipids extration directly. And the total sugar variation may be representing the lipids yield. For later lipids extraction, we can determine the total sugar concentration to predict the extraction end product.

  18. Mechanism of Irradiation Assisted Cracking of Core Components in Light Water Reactors

    SciTech Connect

    Was, Gary S; Atzmon, Michael; Wang, Lumin

    2003-04-28

    The overall goal of the project is to determine the mechanism of irradiation assisted stress corrosion cracking (IASCC). IASCC has been linked to hardening, microstructural and microchemical changes during irradiation. Unfortunately, all of these changes occur simultaneously and at similar rates during irradiation, making attribution of IASCC to any one of these features nearly impossible to determine. The strategy set forth in this project is to develop means to separate microstructural from microchemical changes to evaluate each separately for their effect on IASCC. In the first part, post irradiation annealing (PIA) treatments are used to anneal the irradiated microstructure, leaving only radiation induced segregation (RIS) for evaluation for its contribution to IASCC. The second part of the strategy is to use low temperature irradiation to produce a radiation damage dislocation loop microstructure without radiation induced segregation in order to evaluate the effect of the dislocation microstructure alone.

  19. Stent-assisted mechanical recanalization for symptomatic subacute or chronic middle cerebral artery occlusion

    PubMed Central

    Guo, Dong; Ma, Ji; Li, Teng-Fei; Zhu, Ming; Han, Xin-Wei; Shui, Shao-Feng

    2015-01-01

    To assess the feasibility and short-term effects of treating patients with subacute or chronic middle cerebral artery (M1) occlusion by stent-assisted mechanical recanalization. Six patients with cerebral arteries occlusion underwent surgery. Six cerebral arteries occlusion in 5 patients were successfully recanalized. On postoperative day 1, four patients’ symptoms were relieved and two patients’ symptoms were exacerbated, of which one was significantly improved after 3 days, the other one’s symptoms were recovered to preoperative levels in 2 weeks. No patients died after surgery. No stroke or transient ischemic attack occurred. The average follow-up of was 4.2 months, no worsening of condition, recurrence or death occurred. The results indicate that for patients with subacute or chronic middle cerebral artery (M1) occlusion, mechanical recanalization was technically feasible under the premise of strict case screening. Mechanical recanalization is able to improve ischemic symptoms and promote dysfunction restoration. But its long-term effect remains to be evaluated by further large samples, long-term follow-up studies. PMID:26885148

  20. The Evaluation of Scholarly Activity in Computer-Assisted Language Learning

    ERIC Educational Resources Information Center

    Smith, Bryan; Lafford, Barbara A.

    2009-01-01

    The current study provides guidance for both junior computer-assisted language learning (CALL) researchers as they decide on the most appropriate forms and placement of scholarly activity and also for decision makers attempting to evaluate the scholarly activity of these CALL researchers in their quest for promotion and tenure. In this study, data…

  1. 34 CFR 661.10 - What activities does the Secretary assist under this program?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 3 2012-07-01 2012-07-01 false What activities does the Secretary assist under this program? 661.10 Section 661.10 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION BUSINESS AND INTERNATIONAL EDUCATION PROGRAM What Kinds of Activities Does...

  2. 34 CFR 661.10 - What activities does the Secretary assist under this program?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false What activities does the Secretary assist under this program? 661.10 Section 661.10 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION BUSINESS AND INTERNATIONAL EDUCATION PROGRAM What Kinds of Activities Does...

  3. 34 CFR 661.10 - What activities does the Secretary assist under this program?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What activities does the Secretary assist under this program? 661.10 Section 661.10 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION BUSINESS AND INTERNATIONAL EDUCATION PROGRAM What Kinds of Activities Does...

  4. 34 CFR 642.11 - What activities does the Secretary assist?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false What activities does the Secretary assist? 642.11 Section 642.11 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION TRAINING PROGRAM FOR FEDERAL TRIO PROGRAMS What Types of Projects and Activities Does the...

  5. Resident-Assisted Montessori Programming (Ramp): Training Persons with Dementia to Serve as Group Activity Leaders

    ERIC Educational Resources Information Center

    Camp, Cameron J.; Skrajner, Michael J.

    2004-01-01

    Purpose: The purpose of this study was to determine the effects of an activity implemented by means of Resident-Assisted Montessori Programming (RAMP). Design and Methods: Four persons with early-stage dementia were trained to serve as leaders for a small-group activity played by nine persons with more advanced dementia. Assessments of leaders'…

  6. Mechanisms of hydrogen-assisted fracture in austenitic stainless steel welds.

    SciTech Connect

    Balch, Dorian K.; Sofronis, Petros; Somerday, Brian P.; Novak, Paul

    2005-03-01

    The objective of this study was to quantify the hydrogen-assisted fracture susceptibility of gas-tungsten arc (GTA) welds in the nitrogen-strengthened, austenitic stainless steels 21Cr-6Ni-9Mn (21-6-9) and 22Cr-13Ni-5Mn (22-13-5). In addition, mechanisms of hydrogen-assisted fracture in the welds were identified using electron microscopy and finite-element modeling. Elastic-plastic fracture mechanics experiments were conducted on hydrogen-charged GTA welds at 25 C. Results showed that hydrogen dramatically lowered the fracture toughness from 412 kJ/m{sup 2} to 57 kJ/m{sup 2} in 21-6-9 welds and from 91 kJ/m{sup 2} to 26 kJ/m{sup 2} in 22-13-5 welds. Microscopy results suggested that hydrogen served two roles in the fracture of welds: it promoted the nucleation of microcracks along the dendritic structure and accelerated the link-up of microcracks by facilitating localized deformation. A continuum finite-element model was formulated to test the notion that hydrogen could facilitate localized deformation in the ligament between microcracks. On the assumption that hydrogen decreased local flow stress in accordance with the hydrogen-enhanced dislocation mobility argument, the finite-element results showed that deformation was localized in a narrow band between two parallel, overlapping microcracks. In contrast, in the absence of hydrogen, the finite-element results showed that deformation between microcracks was more uniformly distributed.

  7. Upper extremity muscle tone and response of tidal volume during manually assisted breathing for patients requiring prolonged mechanical ventilation

    PubMed Central

    Morino, Akira; Shida, Masahiro; Tanaka, Masashi; Sato, Kimihiro; Seko, Toshiaki; Ito, Shunsuke; Ogawa, Shunichi; Yokoi, Yuka; Takahashi, Naoaki

    2015-01-01

    [Purpose] The aim of the present study was to examine, in patients requiring prolonged mechanical ventilation, if the response of tidal volume during manually assisted breathing is dependent upon both upper extremity muscle tone and the pressure intensity of manually assisted breathing. [Subjects] We recruited 13 patients on prolonged mechanical ventilation, and assessed their upper extremity muscle tone using the modified Ashworth scale (MAS). The subjects were assigned to either the low MAS group (MAS≤2, n=7) or the high MAS group (MAS≥3, n=6). [Methods] The manually assisted breathing technique was applied at a pressure of 2 kgf and 4 kgf. A split-plot ANOVA was performed to compare the tidal volume of each pressure during manually assisted breathing between the low and the high MAS groups. [Results] Statistical analysis showed there were main effects of the upper extremity muscle tone and the pressure intensity of the manually assisted breathing technique. There was no interaction between these factors. [Conclusion] Our findings reveal that the tidal volume during the manually assisted breathing technique for patients with prolonged mechanical ventilation depends upon the patient’s upper extremity muscle tone and the pressure intensity. PMID:26357431

  8. Promoting Technology-Assisted Active Learning in Computer Science Education

    ERIC Educational Resources Information Center

    Gao, Jinzhu; Hargis, Jace

    2010-01-01

    This paper describes specific active learning strategies for teaching computer science, integrating both instructional technologies and non-technology-based strategies shown to be effective in the literature. The theoretical learning components addressed include an intentional method to help students build metacognitive abilities, as well as…

  9. 78 FR 46829 - Assistance to Foreign Atomic Energy Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ..., 2011, DOE issued a NOPR to propose the updating of part 810 (76 FR 55278). The NOPR listed destinations... activities subject to part 810. 48 FR 2518 (Feb. 4, 1983); 40 FR 44846 (Sep. 30, 1975); 21 FR 418 (Jan. 20, 1956). In 1986, DOE amended Sec. 810.1 to add ``U.S.'' before ``persons'' (51 FR 44570, Dec. 10,...

  10. Mechanisms of Specificity for Hox Factor Activity

    PubMed Central

    Zandvakili, Arya; Gebelein, Brian

    2016-01-01

    Metazoans encode clusters of paralogous Hox genes that are critical for proper development of the body plan. However, there are a number of unresolved issues regarding how paralogous Hox factors achieve specificity to control distinct cell fates. First, how do Hox paralogs, which have very similar DNA binding preferences in vitro, drive different transcriptional programs in vivo? Second, the number of potential Hox binding sites within the genome is vast compared to the number of sites bound. Hence, what determines where in the genome Hox factors bind? Third, what determines whether a Hox factor will activate or repress a specific target gene? Here, we review the current evidence that is beginning to shed light onto these questions. In particular, we highlight how cooperative interactions with other transcription factors (especially PBC and HMP proteins) and the sequences of cis-regulatory modules provide a basis for the mechanisms of Hox specificity. We conclude by integrating a number of the concepts described throughout the review in a case study of a highly interrogated Drosophila cis-regulatory module named “The Distal-less Conserved Regulatory Element” (DCRE). PMID:27583210

  11. Performance of daily activities by older adults with dementia: the role of an assistive robot.

    PubMed

    Begum, Momotaz; Wang, Rosalie; Huq, Rajibul; Mihailidis, Alex

    2013-06-01

    Older adults with cognitive impairment often have difficulties in remembering the proper sequence of activities of daily living (ADLs) or how to use the tools necessary to perform ADLs. They, therefore, require reminders in a timely fashion while performing ADLs. This is a very stressful situation for the caregivers of people with dementia. In this paper we describe a pilot study where a tele-operated assistive robot helps a group of older adults with dementia (OAwD) to perform an ADL, namely making a cup of tea in the kitchen. Five OAwD along with their caregivers participated in this study which took place in a simulated-home setting. The purpose of this study was to investigate the feasibility and usability of a robotic system in assisting the OAwD to perform ADL in a home setting. The findings from this study will contribute to achieve our ultimate goal of designing a full-fledged assistive robot that assists OAwD aging in their own homes. The assistive robots designed for people with dementia mostly focus on companionship. This is, to the best of our knowledge, the first attempt to design an assistive robot which will provide step-by-step guidance to people with dementia in their activities of daily living. PMID:24187224

  12. Assessment of Initial Test Conditions for Experiments to Assess Irradiation Assisted Stress Corrosion Cracking Mechanisms

    SciTech Connect

    Busby, Jeremy T; Gussev, Maxim N

    2011-04-01

    Irradiation-assisted stress corrosion cracking is a key materials degradation issue in today s nuclear power reactor fleet and affects critical structural components within the reactor core. The effects of increased exposure to irradiation, stress, and/or coolant can substantially increase susceptibility to stress-corrosion cracking of austenitic steels in high-temperature water environments. . Despite 30 years of experience, the underlying mechanisms of IASCC are unknown. Extended service conditions will increase the exposure to irradiation, stress, and corrosive environment for all core internal components. The objective of this effort within the Light Water Reactor Sustainability program is to evaluate the response and mechanisms of IASCC in austenitic stainless steels with single variable experiments. A series of high-value irradiated specimens has been acquired from the past international research programs, providing a valuable opportunity to examine the mechanisms of IASCC. This batch of irradiated specimens has been received and inventoried. In addition, visual examination and sample cleaning has been completed. Microhardness testing has been performed on these specimens. All samples show evidence of hardening, as expected, although the degree of hardening has saturated and no trend with dose is observed. Further, the change in hardening can be converted to changes in mechanical properties. The calculated yield stress is consistent with previous data from light water reactor conditions. In addition, some evidence of changes in deformation mode was identified via examination of the microhardness indents. This analysis may provide further insights into the deformation mode under larger scale tests. Finally, swelling analysis was performed using immersion density methods. Most alloys showed some evidence of swelling, consistent with the expected trends for this class of alloy. The Hf-doped alloy showed densification rather than swelling. This observation may be

  13. The Solar Thermal Design Assistance Center report of its activities and accomplishments in Fiscal Year 1993

    SciTech Connect

    Menicucci, D.F.

    1994-03-01

    The Solar Thermal Design Assistance Center (STDAC) at Sandia National Laboratories is a resource provided by the US Department of Energy`s Solar Thermal Program. Its major objectives are to accelerate the use of solar thermal systems through (a) direct technical assistance to users, (b) cooperative test, evaluation, and development efforts with private industry, and (c) educational outreach activities. This report outlines the major activities and accomplishments of the STDAC in Fiscal Year 1993. The report also contains a comprehensive list of persons who contacted the STDAC by telephone for information or technical consulting.

  14. International Assistance for Low-Emission Development Planning: Coordinated Low Emissions Assistance Network (CLEAN) Inventory of Activities and Tools--Preliminary Trends

    SciTech Connect

    Cox, S.; Benioff, R.

    2011-05-01

    The Coordinated Low Emissions Assistance Network (CLEAN) is a voluntary network of international practitioners supporting low-emission planning in developing countries. The network seeks to improve quality of support through sharing project information, tools, best practices and lessons, and by fostering harmonized assistance. CLEAN has developed an inventory to track and analyze international technical support and tools for low-carbon planning activities in developing countries. This paper presents a preliminary analysis of the inventory to help identify trends in assistance activities and tools available to support developing countries with low-emission planning.

  15. Processing, Microstructure and Mechanical Behavior of Ultrasonic Assisted Cast Magnesium 1wt% Silicon Carbide Nano-Composites

    NASA Astrophysics Data System (ADS)

    Erman, Ari

    The goal of this dissertation is to establish an understanding of processing -- microstructure -- mechanical behavior relationship in Mg-1wt% SiC metal matrix nano-composites fabricated via an ultrasonic assisted casting process, with the emphasis on the effect of the distribution of nanoparticles on this relationship. Ultrasonic assisted casting has been proved as an effective technique to distribute nanoparticles in Mg metal matrix nano-composites (MMNCs). Mg MMNCs reinforced with 1 wt% SiC nanoparticles, were cast by ultrasonic cavitation-based dispersion methods. Microstructural analyses of as cast specimens were conducted to characterize the grain size, shape and distribution, SiC nanoparticle size and distribution, and nanoparticle-matrix interface. Average grain size for the ultrasonic assisted cast composite specimens was 72 mum compared to 181 mum for pure Mg samples prepared by the same method. The average measured SiC nanoparticle size was 66 nm. TEM studies showed good local dispersion of SiC nanoparticles, with only a few small, widely spaced clusters. HRTEM showed a clean interface between SiC nanoparticles and the Mg matrix, with no evidence of secondary phases. The yield strength of Mg-1 wt% SiC nanocomposites was 67 MPa, which showed improvement from 47 MPa for the pure Mg samples. This extra strengthening is due to Orowan and Hall-Petch effects. Fatigue experiments were conducted to characterize the cyclic stress-strain response of pure Mg and Mg-1wt% SiC samples at 0.2%, 0.4% and 0.6% plastic strain amplitudes. The analyses of the cyclic stress response curves and hysteresis loops, combined with post failure TEM analyses provided an understanding of the role of twinning, and twin-particle interactions on the cyclic deformation behavior of Mg MMNCs. Tensile twinning and basal slip are the main forms of deformation mechanisms under compression, followed by detwinning and basal slip in subsequent tension. Fatigue lives of Mg MMNCs are comparable to

  16. Mechanical analysis of lunar gravity assist in the Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Qi, Yi; Xu, Shijie

    2015-12-01

    In this paper, the lunar gravity assist (LGA) is investigated under the planar circular restricted three-body problem (PCRTBP) and two-body model. In the PCRTBP, the approximate expression of energy of the LGA in a small region of the Moon is derived. The expression uncovers the mechanism and mechanical process of the LGA in the framework of the PCRTBP. Based on the expression, the change of energy during the LGA is obtained and analyzed. To solve the limitation of the expressions and complete the research range of the LGA, a numerical methodology based on the patched-conic model is presented to analyze the LGA in a large region near the Moon. This numerical methodology cannot only obtain the change of energy but also may classify the trajectories before and after the LGA. As an application, we present a method to design a special kind of double LGA orbit. The design method synthesizes the preliminary results in the patched-conic model and the optimization in the PCRTBP. We can quickly obtain abundant double LGA orbits for the Earth-Moon transfer and interplanetary spaceflight.

  17. The coercivity mechanism of Pr-Fe-B nanoflakes prepared by surfactant-assisted ball milling

    NASA Astrophysics Data System (ADS)

    Zuo, Wen-Liang; Zhang, Ming; Niu, E.; Shao, Xiao-Ping; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2015-09-01

    The strong (00l) textured Pr12+xFe82-xB6 (x=0, 1, 2, 3, 4) nanoflakes with high coercivity were prepared by surfactant-assisted ball milling (SABM). The thickness and length of the flakes are mainly in the range of 50-200 nm and 0.5-2 μm, respectively. A coercivity of 4.16 kOe for Pr15Fe79B6 nanoflakes was obtained, which is the maximum coercivity of R2Fe14B (R=Pr, Nd) nanoflakes or nanoparticles reported up to now. The results of XRD and SEM for the aligned Pr15Fe79B6 nanoflakes indicate that a strong (00l) texture is obtained and the easy magnetization direction is parallel to the surface of the flakes. The angular dependence of coercivity for aligned sample indicates that the coercivity mechanism of the as-milled nanoflakes is mainly dominated by domain wall pinning. Meanwhile, the field dependence of coercivity, isothermal (IRM) and dc demagnetizing (DCD) remanence curves also indicate that the coercivity is mainly determined by domain wall pinning, and nucleation also has an important effect. In addition, the mainly interaction of flakes is dipolar coupling. The research of coercivity mechanism for Pr15Fe79B6 nanoflakes is important for guidance the further increase its value, and is useful for the future development of the high performance nanocomposite magnets and soft/hard exchange spring magnets.

  18. Mechanical blood trauma in assisted circulation: sublethal RBC damage preceding hemolysis.

    PubMed

    Olia, Salim E; Maul, Timothy M; Antaki, James F; Kameneva, Marina V

    2016-06-15

    After many decades of improvements in mechanical circulatory assist devices (CADs), blood damage remains a serious problem during support contributing to variety of adverse events, and consequently affecting patient survival and quality of life. The mechanisms of cumulative cell damage in continuous-flow blood pumps are still not fully understood despite numerous in vitro, in vivo, and in silico studies of blood trauma. Previous investigations have almost exclusively focused on lethal blood damage, namely hemolysis, which is typically negligible during normal operation of current generation CADs. The measurement of plasma free hemoglobin (plfHb) concentration to characterize hemolysis is straightforward, however sublethal trauma is more difficult to detect and quantify since no simple direct test exists. Similarly, while multiple studies have focused on thrombosis within blood pumps and accessories, sublethal blood trauma and its sequelae have yet to be adequately documented or characterized. This review summarizes the current understanding of sublethal trauma to red blood cells (RBCs) produced by exposure of blood to flow parameters and conditions similar to those within CADs. It also suggests potential strategies to reduce and/or prevent RBC sublethal damage in a clinically-relevant context, and encourages new research into this relatively uncharted territory. PMID:27034320

  19. THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE

    SciTech Connect

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q.; Fisher, R. T.; Townsley, D. M.; Meakin, C.; Reid, L. B.

    2012-11-01

    We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

  20. Vision based assistive technology for people with dementia performing activities of daily living (ADLs): an overview

    NASA Astrophysics Data System (ADS)

    As'ari, M. A.; Sheikh, U. U.

    2012-04-01

    The rapid development of intelligent assistive technology for replacing a human caregiver in assisting people with dementia performing activities of daily living (ADLs) promises in the reduction of care cost especially in training and hiring human caregiver. The main problem however, is the various kinds of sensing agents used in such system and is dependent on the intent (types of ADLs) and environment where the activity is performed. In this paper on overview of the potential of computer vision based sensing agent in assistive system and how it can be generalized and be invariant to various kind of ADLs and environment. We find that there exists a gap from the existing vision based human action recognition method in designing such system due to cognitive and physical impairment of people with dementia.

  1. Health Occupations--Dental Assistant. Kit No. 62. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Jackson, Janette

    An instructor's manual and student activity guide on a dental assistant are provided in this set of prevocational education materials which focuses on the vocational area of health occupations. (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings: agriculture, home…

  2. Effects of an Equine Assisted Activities Program on Youth with Emotional Disturbance: A Pilot Study

    ERIC Educational Resources Information Center

    Stebbins, Tira

    2012-01-01

    This study evaluated the effects of a 10-week Equine Assisted Activities (EAA) program on special education students (aged 9 to 15) identified as Emotionally Disturbed (ED) who were enrolled in an alternative school. A control group of special education students receiving treatment-as-usual was included. The Behavior Assessment Scale for Children,…

  3. 76 FR 7870 - Agency Information Collection Activities: Cybersecurity and Communications Technical Assistance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-11

    ... published this ICR in the Federal Register on March 3, 2010, at 75 FR 9608-9609, for a 60-day public comment... SECURITY Agency Information Collection Activities: Cybersecurity and Communications Technical Assistance... Homeland Security (DHS), National Protection and Programs Directorate (NPPD), Office of Cybersecurity...

  4. Teaching Middle School Students with Learning Disabilities To Recruit Peer Assistance during Cooperative Learning Group Activities.

    ERIC Educational Resources Information Center

    Wolford, Patricia L.; Heward, William L.; Alber, Sheila R.

    2001-01-01

    Four 8th graders with learning disabilities were taught to recruit assistance from peers during cooperative learning activities in two general classrooms. Training consisted of modeling, role playing, corrective feedback, and praise. Recruitment training increased the productivity and accuracy with which the students completed their language arts…

  5. Microwave-Assisted Copper-Catalyzed Oxidative Cyclization of Acrylamides with Non-Activated Ketones.

    PubMed

    Zhao, Yaping; Sharma, Nandini; Sharma, Upendra K; Li, Zhenghua; Song, Gonghua; Van der Eycken, Erik V

    2016-04-18

    An operationally simple and efficient microwave-assisted protocol for the oxidative cyclization of acrylamide derivatives with non-activated ketones to generate 3,3-disubstituted oxindoles is described. The reaction proceeds by a copper-catalyzed tandem radical addition/cyclization strategy and tolerates a series of functional groups with moderate to excellent yields. PMID:26868308

  6. 76 FR 42129 - Agency Information Collection Activities: Case Submission Form, Case Assistance Form

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-18

    ... FY2010. We are requesting a two year approval for the form anticipating Government Paperwork Elimination... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Agency Information Collection Activities: Case Submission Form, Case Assistance Form (Form...

  7. Pedagogical Values of Mobile-Assisted Task-Based Activities to Enhance Speaking Skill

    ERIC Educational Resources Information Center

    Mohammadi, Mojtaba; Safdari, Nastaran

    2015-01-01

    The purpose of the present study was to examine the impact of online mobile-assisted task-based activities on improving Iranian intermediate English as a Foreign Language (EFL) learners' speaking skills. To achieve the purpose of the study, 90 intermediate language learners were selected ranging between 13 to 16 years old and divided into three…

  8. 34 CFR 642.10 - Activities the Secretary assists under the Training Program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Activities the Secretary assists under the Training Program. 642.10 Section 642.10 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION TRAINING PROGRAM FOR FEDERAL...

  9. Part 110--Nondiscrimination on the Basis of Age in Programs or Activities Receiving Federal Financial Assistance.

    ERIC Educational Resources Information Center

    Office for Civil Rights (ED), Washington, DC.

    This document addresses nondiscrimination on the basis of age in programs or activities receiving federal financial assistance. It consists of the amendments made in the notice of Final Regulations published in the Federal Register on November 13, 2000. Its purpose is to set out the Department of Education's rules for implementing the Age…

  10. Substrate-Assisted Catalysis in the Reaction Catalyzed by Salicylic Acid Binding Protein 2 (SABP2), a Potential Mechanism of Substrate Discrimination for Some Promiscuous Enzymes.

    PubMed

    Yao, Jianzhuang; Guo, Haobo; Chaiprasongsuk, Minta; Zhao, Nan; Chen, Feng; Yang, Xiaohan; Guo, Hong

    2015-09-01

    Although one of an enzyme's hallmarks is the high specificity for their natural substrates, substrate promiscuity has been reported more frequently. It is known that promiscuous enzymes generally show different catalytic efficiencies to different substrates, but our understanding of the origin of such differences is still lacking. Here we report the results of quantum mechanical/molecular mechanical simulations and an experimental study of salicylic acid binding protein 2 (SABP2). SABP2 has promiscuous esterase activity toward a series of substrates but shows a high activity toward its natural substrate, methyl salicylate (MeSA). Our results demonstrate that this enzyme may use substrate-assisted catalysis involving the hydroxyl group from MeSA to enhance the activity and achieve substrate discrimination. PMID:26244568

  11. Substrate-Assisted Catalysis in the Reaction Catalyzed by Salicylic Acid Binding Protein 2 (SABP2), a Potential Mechanism of Substrate Discrimination for Some Promiscuous Enzymes

    DOE PAGESBeta

    Yao, Jianzhuang; Guo, Haobo; Chaiprasongsuk, Minta; Zhao, Nan; Chen, Feng; Yang, Xiaohan; Guo, Hong

    2015-08-05

    Although one of an enzyme’s hallmarks is the high specificity for their natural substrates, substrate promiscuity has been reported more frequently. We know that promiscuous enzymes generally show different catalytic efficiencies to different substrates, but our understanding of the origin of such differences is still lacking. We report the results of quantum mechanical/molecular mechanical simulations and an experimental study of salicylic acid binding protein 2 (SABP2). SABP2 has promiscuous esterase activity toward a series of substrates but shows a high activity toward its natural substrate, methyl salicylate (MeSA). Finally, our results demonstrate that this enzyme may use substrate-assisted catalysis involvingmore » the hydroxyl group from MeSA to enhance the activity and achieve substrate discrimination.« less

  12. Substrate-Assisted Catalysis in the Reaction Catalyzed by Salicylic Acid Binding Protein 2 (SABP2), a Potential Mechanism of Substrate Discrimination for Some Promiscuous Enzymes

    SciTech Connect

    Yao, Jianzhuang; Guo, Haobo; Chaiprasongsuk, Minta; Zhao, Nan; Chen, Feng; Yang, Xiaohan; Guo, Hong

    2015-08-05

    Although one of an enzyme’s hallmarks is the high specificity for their natural substrates, substrate promiscuity has been reported more frequently. We know that promiscuous enzymes generally show different catalytic efficiencies to different substrates, but our understanding of the origin of such differences is still lacking. We report the results of quantum mechanical/molecular mechanical simulations and an experimental study of salicylic acid binding protein 2 (SABP2). SABP2 has promiscuous esterase activity toward a series of substrates but shows a high activity toward its natural substrate, methyl salicylate (MeSA). Finally, our results demonstrate that this enzyme may use substrate-assisted catalysis involving the hydroxyl group from MeSA to enhance the activity and achieve substrate discrimination.

  13. Design and control of an active 1-DoF mechanism for knee rehabilitation.

    PubMed

    Naghavi, Nader; Mahjoob, Mohammad J

    2016-10-01

    A 1-DoF robot is designed and fabricated to be used for knee rehabilitation training. The mechanism (robot) is designed to perform specific set of exercises while the patient is sitting on a chair. The therapy process for patients has different stages; each stage consists of specific exercises to recover the knee to its condition before injury. The maximum torque of healthy joint during the extension/flexion exercise is evaluated by simulation and suitable actuator is selected based on the results. A prototype is then fabricated as a platform to evaluate the design and control concepts. The experiment procedure consisting of three stages of therapy indicates good tracking performance and safe operation of the system. Implication for Rehabilitation A 1-DoF mechanism for knee rehabilitation has been designed to perform three stages of therapy: passive, active assist and active resist. The assistive and resistive torque, during active assist and active resist stages, can be set according to the progress in therapy. The results of this study suggest the system has the potential to result in various benefits including reduction of physical workload of physiotherapists and improved repeatability. PMID:25811934

  14. Strong magnetic field-assisted growth of carbon nanofibers and its microstructural transformation mechanism

    PubMed Central

    Luo, Chengzhi; Fu, Qiang; Pan, Chunxu

    2015-01-01

    It is well-known that electric and magnetic fields can control the growth direction, morphology and microstructure of one-dimensional carbon nanomaterials (1-DCNMs), which plays a key role for its potential applications in micro-nano-electrics and devices. In this paper, we introduce a novel process for controlling growth of carbon nanofibers (CNFs) with assistance of a strong magnetic field (up to 0.5 T in the center) in a chemical vapor deposition (CVD) system. The results reveal that: 1) The CNFs get bundled when grown in the presence of a strong magnetic field and slightly get aligned parallel to the direction of the magnetic field; 2) The CNFs diameter become narrowed and homogenized with increase of the magnetic field; 3) With the increase of the magnetic field, the microstructure of CNFs is gradually changed, i.e., the strong magnetic field makes the disordered “solid-cored” CNFs transform into a kind of bamboo-liked carbon nanotubes; 4) We propose a mechanism that the reason for these variations and transformation is due to diamagnetic property of carbon atoms, so that it has direction selectivity in the precipitation process. PMID:25761381

  15. A study on dynamic heat assisted magnetization reversal mechanisms under insufficient reversal field conditions

    SciTech Connect

    Chen, Y. J.; Yang, H. Z.; Leong, S. H.; Yu Ko, Hnin Yu; Wu, B. L.; Ng, V.; Asbahi, M.; Yang, J. K. W.

    2014-10-20

    We report an experimental study on the dynamic thermomagnetic (TM) reversal mechanisms at around Curie temperature (Tc) for isolated 60 nm pitch single-domain [Co/Pd] islands heated by a 1.5 μm spot size laser pulse under an applied magnetic reversal field (Hr). Magnetic force microscopy (MFM) observations with high resolution MFM tips clearly showed randomly trapped non-switched islands within the laser irradiated spot after dynamic TM reversal process with insufficient Hr strength. This observation provides direct experimental evidence by MFM of a large magnetization switching variation due to increased thermal fluctuation/agitation over magnetization energy at the elevated temperature of around Tc. The average percentage of non-switched islands/magnetization was further found to be inversely proportional to the applied reversal field Hr for incomplete magnetization reversal when Hr is less than 13% of the island coercivity (Hc), showing an increased switching field distribution (SFD) at elevated temperature of around Tc (where main contributions to SFD broadening are from Tc distribution and stronger thermal fluctuations). Our experimental study and results provide better understanding and insight on practical heat assisted magnetic recording (HAMR) process and recording performance, including HAMR writing magnetization dynamics induced SFD as well as associated DC saturation noise that limits areal density, as were previously observed and investigated by theoretical simulations.

  16. A novel mechanical lung assist system sustains primary bidirectional cavopulmonary shunt circulation in pigs.

    PubMed

    Honjo, Osami; Merklinger, Sandra L; Poe, John; Guerguerian, Anne-Marie; Alghamdi, Abdullah A; Takatani, Setsuo; Van Arsdell, Glen S

    2007-01-01

    Primary creation of a bidirectional cavopulmonary shunt (BCPS), which provides a stable in-series circulation, might improve survival in patients with hypoplastic left heart syndrome. However, pulmonary vascular immaturity and high pulmonary vascular resistance must be overcome to achieve a successful primary neonatal BCPS. This study tested the hypothesis that a novel mechanical lung assist (MLA) system would permit a primary BCPS in juvenile pigs. A BCPS (1(1/2) ventricle repair physiology) was created in nine 4-5-week-old pigs (mean weight 17.9 kg), followed by MLA with a miniature centrifugal pump and a hand-made double-lumen cannula for 2 hours. Systemic and cerebral hemodynamic and metabolic data were evaluated. A mean BCPS flow of 331 +/- 56 ml/min was obtained with a mean pump speed of 3899 +/- 306 rpm at 30 minutes after MLA initiation. Adequate oxygenation, ventilation, and hemodynamics were maintained. Transcranial Doppler ultrasound demonstrated consistent pre- and postoperative peak systolic and diastolic velocities of the middle cerebral artery, indicating sustained cerebral perfusion pressure. This study demonstrated that the MLA is able to sustain a high-resistance BCPS and provides a strategy or rationale for developing a primary neonatal cavopulmonary connection in appropriately selected neonates with congenital heart disease. PMID:18043155

  17. Recent advances in computational methodology for simulation of mechanical circulatory assist devices

    PubMed Central

    Marsden, Alison L.; Bazilevs, Yuri; Long, Christopher C.; Behr, Marek

    2014-01-01

    Ventricular assist devices (VADs) provide mechanical circulatory support to offload the work of one or both ventricles during heart failure. They are used in the clinical setting as destination therapy, as bridge to transplant, or more recently as bridge to recovery to allow for myocardial remodeling. Recent developments in computational simulation allow for detailed assessment of VAD hemodynamics for device design and optimization for both children and adults. Here, we provide a focused review of the recent literature on finite element methods and optimization for VAD simulations. As VAD designs typically fall into two categories, pulsatile and continuous flow devices, we separately address computational challenges of both types of designs, and the interaction with the circulatory system with three representative case studies. In particular, we focus on recent advancements in finite element methodology that has increased the fidelity of VAD simulations. We outline key challenges, which extend to the incorporation of biological response such as thrombosis and hemolysis, as well as shape optimization methods and challenges in computational methodology. PMID:24449607

  18. Pearls and pitfalls in short-term mechanical circulatory assist: how to avoid and manage complications.

    PubMed

    Mohite, Prashant N; Maunz, Olaf; Simon, Andre R

    2014-10-01

    In today's era, given the worsening risk profiles of patients undergoing cardiac surgery, the increasing number of complex cardiac surgeries, and the increasing number of patients undergoing thoracic organ transplantation, short-term mechanical circulatory assist (MCA) devices are indispensable. MCA devices are capable of supporting heart and lung function and have emerged as potentially lifesaving instruments, but may prove to be as hazardous as helpful due to their inherent tendency toward hemolysis, thromboembolism, and hemorrhage. Although MCA devices are being used regularly at some specialized centers, surgeries involving MCA are not as common as other routine cardiac surgeries, and even though professionals implanting and maintaining short-term MCAs are well acquainted with operating such devices, it is not uncommon to come across complications as a result of minor mistakes committed while dealing with them. Avoiding simple mistakes and taking proper precautions while implanting and maintaining these devices can prevent major catastrophes. We discuss commonly encountered problems and complications during the implantation and maintenance of short-term MCAs and offer reasonable and practical solutions. In addition, crucial issues such as anticoagulation, replacement of the device circuit, and management of the distal perfusion cannula are discussed. Continuous and efficient monitoring of the MCA device and the patient supported on MCA, together with anticipation and avoidance of complications, is key for successful short-term MCA support. PMID:24533589

  19. Strong magnetic field-assisted growth of carbon nanofibers and its microstructural transformation mechanism.

    PubMed

    Luo, Chengzhi; Fu, Qiang; Pan, Chunxu

    2015-01-01

    It is well-known that electric and magnetic fields can control the growth direction, morphology and microstructure of one-dimensional carbon nanomaterials (1-DCNMs), which plays a key role for its potential applications in micro-nano-electrics and devices. In this paper, we introduce a novel process for controlling growth of carbon nanofibers (CNFs) with assistance of a strong magnetic field (up to 0.5 T in the center) in a chemical vapor deposition (CVD) system. The results reveal that: 1) The CNFs get bundled when grown in the presence of a strong magnetic field and slightly get aligned parallel to the direction of the magnetic field; 2) The CNFs diameter become narrowed and homogenized with increase of the magnetic field; 3) With the increase of the magnetic field, the microstructure of CNFs is gradually changed, i.e., the strong magnetic field makes the disordered "solid-cored" CNFs transform into a kind of bamboo-liked carbon nanotubes; 4) We propose a mechanism that the reason for these variations and transformation is due to diamagnetic property of carbon atoms, so that it has direction selectivity in the precipitation process. PMID:25761381

  20. Strong magnetic field-assisted growth of carbon nanofibers and its microstructural transformation mechanism

    NASA Astrophysics Data System (ADS)

    Luo, Chengzhi; Fu, Qiang; Pan, Chunxu

    2015-03-01

    It is well-known that electric and magnetic fields can control the growth direction, morphology and microstructure of one-dimensional carbon nanomaterials (1-DCNMs), which plays a key role for its potential applications in micro-nano-electrics and devices. In this paper, we introduce a novel process for controlling growth of carbon nanofibers (CNFs) with assistance of a strong magnetic field (up to 0.5 T in the center) in a chemical vapor deposition (CVD) system. The results reveal that: 1) The CNFs get bundled when grown in the presence of a strong magnetic field and slightly get aligned parallel to the direction of the magnetic field; 2) The CNFs diameter become narrowed and homogenized with increase of the magnetic field; 3) With the increase of the magnetic field, the microstructure of CNFs is gradually changed, i.e., the strong magnetic field makes the disordered ``solid-cored'' CNFs transform into a kind of bamboo-liked carbon nanotubes; 4) We propose a mechanism that the reason for these variations and transformation is due to diamagnetic property of carbon atoms, so that it has direction selectivity in the precipitation process.

  1. Mechanisms of defect complex formation and environmental-assisted fracture behavior of iron aluminides

    SciTech Connect

    Cooper, B.R.; Muratov, L.S.; Kang, B.S.J.; Li, K.Z.

    1997-12-01

    Iron aluminide has excellent corrosion resistance in high-temperature oxidizing-sulfidizing environments; however, there are problems at room and medium temperature with hydrogen embrittlement as related to exposure to moisture. In this research, a coordinated computational modeling/experimental study of mechanisms related to environmental-assisted fracture behavior of selected iron aluminides is being undertaken. The modeling and the experimental work will connect at the level of coordinated understanding of the mechanisms for hydrogen penetration and for loss of strength and susceptibility to fracture. The focus of the modeling component at this point is on the challenging question of accurately predicting the iron vacancy formation energy in Fe{sub 3}A{ell} and the subsequent tendency, if present, for vacancy clustering. The authors have successfully performed, on an ab initio basis, the first calculation of the vacancy formation energy in Fe{sub 3}A{ell}. These calculations include lattice relaxation effects which are quite large. This has significant implications for vacancy clustering effects with consequences to be explored for hydrogen diffusion. The experimental work at this stage has focused on the relationship of the choice and concentration of additives to the improvement of resistance to hydrogen embrittlement and hence to the fracture behavior. For this reason, comparative crack growth tests of FA-186, FA-187, and FA-189 iron aluminides (all with basic composition of Fe-28A{ell}-5Cr, at % with micro-alloying additives of Zr, C or B) under, air, oxygen, or water environment have been performed. These tests showed that the alloys are susceptible to room temperature hydrogen embrittlement in both B2 and DO{sub 3} conditions. Test results indicated that FA-187, and FA-189 are intrinsically more brittle than FA-186.

  2. Platelet Activation: The Mechanisms and Potential Biomarkers

    PubMed Central

    Yun, Seong-Hoon; Sim, Eun-Hye; Goh, Ri-Young; Park, Joo-In

    2016-01-01

    Beyond hemostasis and thrombosis, an increasing number of studies indicate that platelets play an integral role in intercellular communication, mediating inflammatory and immunomodulatory activities. Our knowledge about how platelets modulate inflammatory and immunity has greatly improved in recent years. In this review, we discuss recent advances in the pathways of platelet activation and potential application of platelet activation biomarkers to diagnosis and prediction of disease states. PMID:27403440

  3. Aminoacetylation Reaction Catalyzed by Leucyl-tRNA Synthetase Operates via a Self-Assisted Mechanism Using a Conserved Residue and the Aminoacyl Substrate.

    PubMed

    Aleksandrov, Alexey; Palencia, Andrés; Cusack, Stephen; Field, Martin

    2016-05-19

    Leucyl-tRNA synthetase catalyzes attachment of leucine amino acid to its cognate tRNA. During the second, aminoacetylation, step of the reaction, the leucyl moiety is transferred from leucyl-adenylate to the terminal A76 adenosine of tRNA. In this work, we have investigated the aminoacetylation step catalyzed by leucyl-tRNA synthase, using ab initio quantum chemical/molecular mechanical hybrid potentials in conjunction with reaction-path-location algorithms and molecular dynamics free energy simulations. We have modeled reaction mechanisms arising from both crystallographic studies and computational work. We invoke various groups as potential proton acceptors-namely, the phosphate and leucyl amino groups of leucyl-adenylate, the A76 base of tRNA, and the Asp80 and Glu532 residues of the protein-and consider both metal-assisted and metal-free reactions. Free energy calculations indicate that both the phosphate group of leucyl adenylate and Glu532 are not strong bases. This agrees with the results of the quantum chemical/molecular mechanical reaction path calculations which give high free energy barriers for the studied pathways involving these groups. A self-assisted mechanism with the leucyl amino group and Asp80 as proton acceptors is the most likely. Furthermore, in this mechanism the presence of a metal ion coordinated by the phosphate group and Glu532 strongly activates the reaction. PMID:27115861

  4. Proton-Assisted Mechanism of NO Reduction on a Dinuclear Ruthenium Complex.

    PubMed

    Suzuki, Tatsuya; Tanaka, Hiromasa; Shiota, Yoshihito; Sajith, P K; Arikawa, Yasuhiro; Yoshizawa, Kazunari

    2015-08-01

    Density-functional-theory (DFT) calculations are performed for the proposal of a plausible mechanism on the reduction of NO to N2O by a dinuclear ruthenium complex, reported by Arikawa and co-workers [J. Am. Chem. Soc. 2007, 129, 14160]. On the basis of the experimental fact that the reduction proceeds under strongly acidic conditions, the role of protons in the mechanistic pathways is investigated with model complexes, where one or two NO ligands are protonated. The reaction mechanism of the NO reduction is partitioned into three steps: reorientation of N2O2 (cis-NO dimer), O-N bond cleavage, and N2O elimination. A key finding is that the protonation of the NO ligand(s) significantly reduces the activation barrier in the rate-determining reorientation step. The activation energy of 43.1 kcal/mol calculated for the proton-free model is reduced to 30.2 and 17.6 kcal/mol for the mono- and diprotonated models, respectively. The protonation induces the electron transfer from the Ru(II)Ru(II) core to the O═N-N═O moiety to give a Ru(III)Ru(III) core and a hyponitrite (O-N═N-O)(2-) species. The formation of the hyponitrite species provides an alternative pathway for the N2O2 reorientation, resulting in the lower activation energies in the presence of proton(s). The protonation also has a marginal effect on the O-N bond cleavage and the N2O elimination steps. Our calculations reveal a remarkable role of protons in the NO reduction via N2O formation and provide new insights into the mechanism of NO reduction catalyzed by metalloenzymes such as nitric oxide reductase (NOR) that contains a diiron active site. PMID:26186365

  5. Guide to federal export assistance activities applicable to the US coal and coal technologies industry

    SciTech Connect

    Not Available

    1989-09-01

    The federal government provides a complete range of programs and services that can assist United States (US) coal and coal-technology firms as they expand into the foreign marketplace. These programs cover the spectrum of business export needs, which include: providing assistance in identifying target markets, locating specific business opportunities and foreign joint-venture partners, arranging business appointments, organizing trade missions, sponsoring feasibility studies, conducting trade analyses, providing financing, insuring investments, and providing in-country training and assistance. Under the sponsorship of the Department of Energy's (DOE) Office of Fossil Energy (FE), this Guide has been developed to address this problem. It is intended to provide coal and coal technology firms with a single reference source for identifying US government agencies, programs, and contacts that might aid in exporting. The Guide contains an in-depth discussion of the eight major agencies offering export assistance: the Agency for International Development (AID), the Departments of Commerce (DOC) and State (DOS), the Export-Import Bank (Eximbank), the Overseas Private Investment Corporation (OPIC), the Small Business Administration (SBA), the Trade and Development Program (TDP), and the Office of the US Trade Representative (USTR). In addition, this guide identifies pertinent activities performed by other federal agencies that might assist coal and coal-technologies exporters, including the Departments of Defense (DOD), Education, Energy (DOE), and Labor (DOL).

  6. 34 CFR 380.6 - What activities may the Secretary fund under technical assistance supported employment projects?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true What activities may the Secretary fund under technical... WITH THE MOST SEVERE DISABILITIES AND TECHNICAL ASSISTANCE PROJECTS General § 380.6 What activities may the Secretary fund under technical assistance supported employment projects? The following...

  7. Animal-Assisted Activities for Students with Disabilities: Obtaining Stakeholders' Approval and Planning Strategies for Teachers

    ERIC Educational Resources Information Center

    Baumgartner, Erin; Cho, Jeong-il

    2014-01-01

    Animal-human interactions have been found to have positive influences on children across the world. In particular, research supports the benefits of animal-assisted activities in addressing students' social and behavioral problems within the classroom environment. The general information about animal-assisted activities provided in this…

  8. Characterization and growth mechanisms of boron nitride films synthesized by ion-beam-assisted deposition

    NASA Astrophysics Data System (ADS)

    Burat, O.; Bouchier, D.; Stambouli, V.; Gautherin, G.

    1990-09-01

    We have studied boron nitride films deposited at room temperature by ion-beam-assisted deposition in an ultrahigh vacuum apparatus, with ion accelerating voltages ranging between 0.25 and 2 kV. By using complementarily in situ Auger electron spectrometry and ex situ nuclear analyses to determine the respective surface and bulk N concentrations in the deposited films, we were able to identify the different phases of the mechanism leading to the nitridation of evaporated boron by nitrogen ions. For low nitrogen/boron flux ratios, the incorporation of nitrogen seems to be only governed by ion implantation, and, with respect to the depth of the deposit, the surface is found largely depleted in nitrogen, while the N-incorporation yield remains close to one whatever the ion energy. Such a behavior is well verified as long as a critical bulk nitrogen concentration close to 5.5×1022 cm-3 has not been achieved. For concentrations greater than this, superstoichiometric material is obtained up to a saturation which corresponds to a bulk N incorporation ranging from 6 to 7×1022 cm-3. Further increase of the N/B flux ratio induces a strong diffusion process from N-rich bulk to N-depleted surface, which results in the nitridation of surface boron atoms and a loss of nitrogen by sputtering or desorption. The density measurements seem to indicate that the synthesized phase is close to h-BN. However, the density of B-rich layers ([N]/[B]≊0.2-0.3) is found to be very close to that calculated for a mixture of pure boron and c-BN. The transparency and microhardness of the synthesized BN have satisfying values for its application as a wear-resistant optical coating, but it is not c-BN.

  9. Nanoscale silicon surface-assisted laser desorption/ionization mass spectrometry: environment stability and activation by simple vacuum oven desiccation.

    PubMed

    Tsao, Chia-Wen; Lin, Yuan-Jing; Chen, Pi-Yu; Yang, Yu-Liang; Tan, Say Hwa

    2016-08-01

    Nanoscale silicon surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is an emerging matrix-free, highly sensitive MS analysis method. An important challenge in using nanoscale silicon SALDI-MS analysis is the aging and stability of silicon after storage in various environments. No proper nanoscale silicon SALDI-MS activation procedure has been reported to solve this issue. This study investigated the sensitivity, wettability, and surface oxidation behavior of nanoscale silicon surface SALDI-MS in a room, an inert gas atmosphere, and a vacuum environment. A simple vacuum oven desiccation was proposed to activate the SALDI-MS surface, and the limit of detection was further enhanced 1000 times to a 500 attomole level using this approach. The long-term stability and desorption/ionization mechanism were also investigated. PMID:27315049

  10. Effects of chemical feedback on respiratory motor and ventilatory output during different modes of assisted mechanical ventilation.

    PubMed

    Mitrouska, J; Xirouchaki, N; Patakas, D; Siafakas, N; Georgopoulos, D

    1999-04-01

    The purpose of the study was to examine the effects of chemical feedback on respiratory motor and ventilatory output in conscious subjects ventilated on various modes of assisted mechanical ventilation. Seven subjects were connected to a ventilator and randomly ventilated on assist-volume control (AVC), pressure support (PS) or proportional assist ventilation (PAV). On each mode, the assist level was set to the highest comfortable level. Airway and oesophageal (Poes) pressures, tidal volume, respiratory frequency (fR) and end-tidal carbon dioxide tension (PET,CO2) were measured breath-by-breath. When the subjects were stable on each mode, the fraction of inspired carbon dioxide (FI,CO2) was increased stepwise, and changes in minute ventilation (V'E) and respiratory motor output, estimated by the pressure-time product of all the respiratory muscles per breath (PTPrm) and per minute (PTPminute), were observed. At zero FI,CO2, PTPminute/PET,CO2 did not differ between modes, while V'E/ PTPminute was significantly lower with PAV than that with PS and AVC. As a result V'E/PET,CO2 was significantly lower with PAV, preventing, unlike AVC and PS, a significant drop in PET,CO2. With PAV, independent of CO2, V'E/PTPminute remained constant, while it decreased significantly with increasing CO2 stimulus with PS and AVC. At high PET,CO2 respiratory effort was significantly lower with PAV than that with PS and AVC. In conclusion, the mode of mechanical ventilation modifies the effects of chemical feedback on respiratory motor and ventilatory output. At all carbon dioxide stimulus levels neuroventilatory coupling was better preserved with proportional assist ventilation than with pressure support and assist-volume control ventilation. PMID:10362056

  11. Qualification of active mechanical components for nuclear power plants

    SciTech Connect

    Allen, R.D.; Mollerus, F.J.

    1983-11-01

    The Electric Power Research Institute has undertaken a study of active safety related mechanical components in domestic nuclear plants to determine what qualification information exists and to establish a plan for qualification of those components. Active safety related mechanical components are those which undergo mechanical motion to perform a safety function. The overall objective of the study is to recommend appropriate methods and realistic criteria for the environmental, seismic and dynamic qualification of active mechanical components. This paper presents the results of progress in this project through May 1983.

  12. Stagnation pressure activated fuel release mechanism for hypersonic projectiles

    DOEpatents

    Cartland, Harry E.; Hunter, John W.

    2003-01-01

    A propulsion-assisted projectile has a body, a cowl forming a combustion section and a nozzle section. The body has a fuel reservoir within a central portion of the body, and a fuel activation system located along the central axis of the body and having a portion of the fuel activation system within the fuel reservoir. The fuel activation system has a fuel release piston with a forward sealing member where the fuel release piston is adapted to be moved when the forward sealing member is impacted with an air flow, and an air-flow channel adapted to conduct ambient air during flight to the fuel release piston.

  13. Enhanced antioxidant and antityrosinase activities of longan fruit pericarp by ultra-high-pressure-assisted extraction.

    PubMed

    Prasad, K Nagendra; Yang, Bao; Shi, John; Yu, Chunyan; Zhao, Mouming; Xue, Sophia; Jiang, Yueming

    2010-01-20

    The health benefits of fruits acting against chronic diseases are ascribed to their antioxidant activities which are mainly responsible due to the presence of phenolic compounds. The use of ultra-high-pressure-assisted extraction (UHPE) has shown great advantages for the extraction of these phenolic compounds from longan fruit pericarp (LFP). Studies were carried out to investigate the effects of UHPE at pressures of 200, 300, 400 and 500 MPa on total phenolic contents, extraction yield, antioxidant and antityrosinase activities from LFP. The antioxidant activities of these extracts were analyzed, using various antioxidant models like 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, total antioxidant capacity and superoxide anion radical scavenging activity. Extract from ultra-high-pressure-assisted extraction at 500MPa (UHPE-500) showed the highest antioxidant activities of all the tested models. In addition, it also showed moderate tyrosinase inhibitory activity. Three phenolic acids, namely gallic acid, ellagic acid, and corilagin were identified and quantified by HPLC. Corilagin content was the highest compared to other phenolic acids identified. UHPE-500 obtained the higher phenolic acid contents compared to other high pressure processing and conventional extractions (CE). Compared with CE, UHPE-500 exhibited good extraction effectiveness in terms of higher extraction yields with high phenolic contents and also with higher antioxidant and antityrosinase activities. PMID:19345542

  14. AMPK activators: mechanisms of action and physiological activities.

    PubMed

    Kim, Joungmok; Yang, Goowon; Kim, Yeji; Kim, Jin; Ha, Joohun

    2016-01-01

    AMP-activated protein kinase (AMPK) is a central regulator of energy homeostasis, which coordinates metabolic pathways and thus balances nutrient supply with energy demand. Because of the favorable physiological outcomes of AMPK activation on metabolism, AMPK has been considered to be an important therapeutic target for controlling human diseases including metabolic syndrome and cancer. Thus, activators of AMPK may have potential as novel therapeutics for these diseases. In this review, we provide a comprehensive summary of both indirect and direct AMPK activators and their modes of action in relation to the structure of AMPK. We discuss the functional differences among isoform-specific AMPK complexes and their significance regarding the development of novel AMPK activators and the potential for combining different AMPK activators in the treatment of human disease. PMID:27034026

  15. AMPK activators: mechanisms of action and physiological activities

    PubMed Central

    Kim, Joungmok; Yang, Goowon; Kim, Yeji; Kim, Jin; Ha, Joohun

    2016-01-01

    AMP-activated protein kinase (AMPK) is a central regulator of energy homeostasis, which coordinates metabolic pathways and thus balances nutrient supply with energy demand. Because of the favorable physiological outcomes of AMPK activation on metabolism, AMPK has been considered to be an important therapeutic target for controlling human diseases including metabolic syndrome and cancer. Thus, activators of AMPK may have potential as novel therapeutics for these diseases. In this review, we provide a comprehensive summary of both indirect and direct AMPK activators and their modes of action in relation to the structure of AMPK. We discuss the functional differences among isoform-specific AMPK complexes and their significance regarding the development of novel AMPK activators and the potential for combining different AMPK activators in the treatment of human disease. PMID:27034026

  16. A new work mechanism on neuronal activity.

    PubMed

    Wang, Rubin; Tsuda, Ichiro; Zhang, Zhikang

    2015-05-01

    By re-examining the neuronal activity energy model, we show the inadequacies in the current understanding of the energy consumption associated with neuron activity. Specifically, we show computationally that a neuron first absorbs and then consumes energy during firing action potential, and this result cannot be produced from any current neuron models or biological neural networks. Based on this finding, we provide an explanation for the observation that when neurons are excited in the brain, blood flow increases significantly while the incremental oxygen consumption is very small. We can also explain why external stimulation and perception emergence are synchronized. We also show that negative energy presence in neurons at the sub-threshold state is an essential reason that leads to blood flow incremental response time in the brain rather than neural excitation to delay. PMID:25640576

  17. Home Accidents and Assistance in Daily Activities of Older Women in Turkey

    ERIC Educational Resources Information Center

    Erkal, Sibel; Sahin, Hande

    2010-01-01

    This study analyzed the relation between incidents of at-home accidents and the assistance in daily activities of women age of 65+ living in the area of Dikmen Akpinar Health Care Unit in Ankara-Turkey. Of the women, 49.2% had experienced a home accident in the last 12 months. More than half of these accidents were caused by falling. Women over…

  18. An investigation of cutting mechanics in 2 dimensional ultrasonic vibration assisted milling toward chip thickness and chip formation

    NASA Astrophysics Data System (ADS)

    Rasidi, I. I.; Rafai, N. H.; Rahim, E. A.; Kamaruddin, S. A.; Ding, H.; Cheng, K.

    2015-12-01

    The purpose of this paper is to investigate the effects of 2 dimensional Ultrasonic Vibration Assisted Milling (UVAM) cutting mechanics, considering tool path trajectory and the effect on the chip thickness. The theoretical modelling of cutting mechanics is focused by considering the trajectory of the tool locus into the workpiece during the machining. The studies found the major advantages of VAM are come from the intermittent tool tip interaction phenomena between cutting tool and workpiece. The reduction of thinning chip thickness formations can be identifying advantages from vibration assisted milling in 2 dimensional. The finding will be discussing the comparison between conventional machining the potential of the advantages toward the chip thickness and chip formation in conclusion.

  19. Three-dimensional laser flow measurements of a patient-specific fontan physiology with mechanical circulatory assistance.

    PubMed

    Chopski, Steven G; Rangus, Owen M; Downs, Emily A; Moskowitz, William B; Throckmorton, Amy L

    2015-06-01

    Mechanical assistance of the Fontan circulation is hypothesized to enhance ventricular preload and improve cardiac output; however, little is known about the fluid dynamics. This study is the first to investigate the three-dimensional flow conditions of a blood pump in an anatomic Fontan. Laser measurements were conducted having an axial flow impeller in the inferior vena cava. Experiments were performed for a physiologic cardiac output, pulmonary arterial flows, and pump speeds of 1000-4000 rpm. The impeller had a modest effect on the flow conditions entering the total cavopulmonary connection at low pump speeds, but a substantial impact on the velocity at higher speeds. The higher speeds of the pump disrupted the recirculation region in the center of the anastomosis, which could be advantageous for washout purposes. No retrograde velocities in the superior vena cava were measured. These findings indicate that mechanical assistance is a viable therapeutic option for patients having dysfunctional single ventricle physiology. PMID:25865262

  20. Mechanism for Clastogenic Activity of Naphthalene

    SciTech Connect

    Buchholz, Bruce A.

    2015-09-29

    Naphthalene incubations form DNA adducts in vitro in a dose dependent manner in both mouse and rat tissues. Rodent tissue incubations with naphthalene indicate that naphthalene forms as many DNA adducts as Benzo(a)pyrene, a known DNA binding carcinogen. The mouse airway has the greatest number of DNA adducts, corresponding to the higher metabolic activation of naphthalene in this location. Both rat tissues, the rat olfactory (tumor target) and the airways (non-tumor target), have similar levels of NA-DNA adducts, indicating that short term measures of initial adduct formation do not directly correlate with sites of tumor formation in the NTP bioassays.

  1. Ultrasonic-Assisted Enzymolysis to Improve the Antioxidant Activities of Peanut (Arachin conarachin L.) Antioxidant Hydrolysate

    PubMed Central

    Yu, Lina; Sun, Jie; Liu, Shaofang; Bi, Jie; Zhang, Chushu; Yang, Qingli

    2012-01-01

    The objective of this work is to provide a theoretical basis for preparing peanut antioxidant hydrolysate in order to improve its antioxidant activities. Therefore, response surface methodology (RSM) based on the Box-Behnken design was used to optimize ultrasonic-assisted enzymolysis for the purpose of preparing peanut antioxidant hydrolysate. Results indicated that the DPPH free radical scavenging activity of peanut hydrolysate could reach 90.06% under the following optimum conditions: ultrasonic power of 150.0 w, reaction temperature of 62.0 °C, incubation time of 25.0 min, and initial pH value of 8.5. The DPPH free radical scavenging rate of peanut hydrolysate from ultrasonic-assisted enzymolysis improved comparing with that of peanut hydrolysate from protease hydrolysis alone. The peanut antioxidant hydrolysate was found to display eight improved kinds of antioxidant activities. In conclusion, the optimal ultrasonic-assisted enzymolysis technology conditions described in this paper, appear to be beneficial for preparing peanut antioxidant hydrolysate. PMID:22942751

  2. Mechanism of antibacterial activity of copper nanoparticles

    NASA Astrophysics Data System (ADS)

    Chatterjee, Arijit Kumar; Chakraborty, Ruchira; Basu, Tarakdas

    2014-04-01

    In a previous communication, we reported a new method of synthesis of stable metallic copper nanoparticles (Cu-NPs), which had high potency for bacterial cell filamentation and cell killing. The present study deals with the mechanism of filament formation and antibacterial roles of Cu-NPs in E. coli cells. Our results demonstrate that NP-mediated dissipation of cell membrane potential was the probable reason for the formation of cell filaments. On the other hand, Cu-NPs were found to cause multiple toxic effects such as generation of reactive oxygen species, lipid peroxidation, protein oxidation and DNA degradation in E. coli cells. In vitro interaction between plasmid pUC19 DNA and Cu-NPs showed that the degradation of DNA was highly inhibited in the presence of the divalent metal ion chelator EDTA, which indicated a positive role of Cu2+ ions in the degradation process. Moreover, the fast destabilization, i.e. the reduction in size, of NPs in the presence of EDTA led us to propose that the nascent Cu ions liberated from the NP surface were responsible for higher reactivity of the Cu-NPs than the equivalent amount of its precursor CuCl2; the nascent ions were generated from the oxidation of metallic NPs when they were in the vicinity of agents, namely cells, biomolecules or medium components, to be reduced simultaneously.

  3. Smooth muscle cell calcium activation mechanisms

    PubMed Central

    Berridge, Michael J

    2008-01-01

    Smooth muscle cell (SMC) contraction is controlled by the Ca2+ and Rho kinase signalling pathways. While the SMC Rho kinase system seems to be reasonably constant, there is enormous variation with regard to the mechanisms responsible for generating Ca2+ signals. One way of dealing with this diversity is to consider how this system has been adapted to control different SMC functions. Phasic SMCs (vas deferens, uterus and bladder) rely on membrane depolarization to drive Ca2+ influx across the plasma membrane. This depolarization can be induced by neurotransmitters or through the operation of a membrane oscillator. Many tonic SMCs (vascular, airway and corpus cavernosum) are driven by a cytosolic Ca2+ oscillator that generates periodic pulses of Ca2+. A similar oscillator is present in pacemaker cells such as the interstitial cells of Cajal (ICCs) and atypical SMCs that control other tonic SMCs (gastrointestinal, urethra, ureter). The changes in membrane potential induced by these cytosolic oscillators does not drive contraction directly but it functions to couple together individual oscillators to provide the synchronization that is a characteristic feature of many tonic SMCs. PMID:18787034

  4. Mechanism of photodynamic activity of pheophorbides

    NASA Astrophysics Data System (ADS)

    Tanielian, Charles; Kobayashi, Masami; Wolff, Christian

    2001-04-01

    Plasmid DNA is efficiently photocleaved by sodium pheophorbides (Na-Phdes) a and b in the absence of oxygen as well as in the presence of oxygen. Fluorescence microscopic observation shows a rapid incorporation of Na-Phde a into nuclei, mitochondria, and lysosome of human oral mucosa cells. In contrast Na-Phde b is incorporated only into the plasma membrane. The photodynamic activity of these pigments in living tissues is probably determined by the monomeric pigment molecules formed in hydrophobic cellular structures and involves two types of reactions: (1) direct electron transfer between DNA bases (especially guanine) and pheophorbide singlet excited state, and (2) indirect reactions medicated by reactive oxygen species, including singlet oxygen whose production from molecular oxygen is sensitized by the Na-Phdes triplet state.

  5. Exploring the mechanisms used by promiscuous chaperones to assist protein folding in the cell

    NASA Astrophysics Data System (ADS)

    Jewett, Andrew I.

    There are two popular theories to explain how molecular chaperones boost the yield of folded protein in the cell: According to the Anfinsen cage model, (ACM) chaperonins protect denatured proteins from aggregation. A competing theory, the iterative annealing model (IAM) claims that ATP regulated chaperone binding and release accelerates folding by freeing proteins from long-lived kinetic traps. We present experimental and kinetic evidence to argue that the IAM is not a complete picture of how the GroEL/ES chaperonin works. Surprisingly some substrate proteins experience folding rate enhancements without undergoing multiple rounds of ATP-induced binding and release from the chaperonin. An explanation of this data requires going beyond the ACM and IAM models. Our work uses molecular dynamics simulations to investigate the folding of a highly frustrated protein within a chaperonin cavity. The chaperonin interior is modeled by a sphere with variable degree of attraction to the protein inside. We demonstrate that this cavity, similar to the weakly hydrophobic interior of the GroEL cavity upon complexion with ATP and GroES, is sufficient to accelerate the folding of a frustrated protein by more than an order of magnitude. Our simulations uncover a novel form of the IAM in which the substrate exhibits spontaneous binding and release from the wall of the chaperonin cage. This mimics the behavior observed in the standard IAM, with the difference that thermal fluctuations, rather than ATP, allow the substrate to unbind from the chaperone. An growing number of smaller cageless chaperones have been discovered that can assist protein folding without the consumption of ATP, including artificial "minichaperones" (fragments of larger chaperones). It is tempting to speculate that the same thermally-driven IAM mechanism could play a role with these chaperones as well. We performed additional simulations of protein folding outside the sphere. We find that in order to accelerate

  6. Experimental investigation on the mechanism of chelation-assisted, copper(II) acetate-accelerated azide-alkyne cycloaddition.

    PubMed

    Kuang, Gui-Chao; Guha, Pampa M; Brotherton, Wendy S; Simmons, J Tyler; Stankee, Lisa A; Nguyen, Brian T; Clark, Ronald J; Zhu, Lei

    2011-09-01

    A mechanistic model is formulated to account for the high reactivity of chelating azides (organic azides capable of chelation-assisted metal coordination at the alkylated azido nitrogen position) and copper(II) acetate (Cu(OAc)(2)) in copper(II)-mediated azide-alkyne cycloaddition (AAC) reactions. Fluorescence and (1)H NMR assays are developed for monitoring the reaction progress in two different solvents, methanol and acetonitrile. Solvent kinetic isotopic effect and premixing experiments give credence to the proposed different induction reactions for converting copper(II) to catalytic copper(I) species in methanol (methanol oxidation) and acetonitrile (alkyne oxidative homocoupling), respectively. The kinetic orders of individual components in a chelation-assisted, copper(II)-accelerated AAC reaction are determined in both methanol and acetonitrile. Key conclusions resulting from the kinetic studies include (1) the interaction between copper ion (either in +1 or +2 oxidation state) and a chelating azide occurs in a fast, pre-equilibrium step prior to the formation of the in-cycle copper(I)-acetylide, (2) alkyne deprotonation is involved in several kinetically significant steps, and (3) consistent with prior experimental and computational results by other groups, two copper centers are involved in the catalysis. The X-ray crystal structures of chelating azides with Cu(OAc)(2) suggest a mechanistic synergy between alkyne oxidative homocoupling and copper(II)-accelerated AAC reactions, in which both a bimetallic catalytic pathway and a base are involved. The different roles of the two copper centers (a Lewis acid to enhance the electrophilicity of the azido group and a two-electron reducing agent in oxidative metallacycle formation, respectively) in the proposed catalytic cycle suggest that a mixed valency (+2 and +1) dinuclear copper species be a highly efficient catalyst. This proposition is supported by the higher activity of the partially reduced Cu(OAc)(2) in

  7. Biomolecule-assisted synthesis of single-crystalline selenium nanowires and nanoribbons via a novel flake-cracking mechanism

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Ye, Xingchen; Dai, Wei; Hou, Weiyi; Zuo, Fan; Xie, Yi

    2006-01-01

    Recently, the biomolecule-assisted synthesis method has been a new and promising focus in the preparation of various nanomaterials. But current works mainly focus on the synthesis of metal nanoparticles and nanowires using macro-biomolecules (e.g. virus, protein and DNA) as templates in the presence of a reducing agent. Beta-carotene, one of the most common bio-antioxidants, can be oxidized to form species with both hydrophilic and hydrophobic ends, which can provide an in situ soft template for the synthesis of nanomaterials. Herein, a simple beta-carotene-assisted method was developed for the first time to synthesize t-Se nanowires and nanoribbons with high crystallinity. We demonstrate that beta-carotene serves as not only the reducing agent, but also an in situ template in the preparation of Se one-dimensional nanostructures. It is found that the growth mechanism of Se nanomaterials is different from the familiar sphere-wire process. A novel flake-cracking mechanism is proposed. By this biomolecule-assisted route, Te one-dimensional nanostructures and Pd nanowires were also fabricated. The assisted-biomolecule in our method may be spread to carotenoids and other antioxidants, and thus broaden the application fields of biomolecules. Our preliminary investigations have shown that the facile, solution-phase biomolecule-assisted method can be potentially extended to the preparation of other low-dimensional nanostructures. The synthesized t-Se nanowires and nanoribbons may serve as templates to generate other tubular functional nanomaterials and find applications in the studies of structure-property relationships as well as in the fabrication of nanoscale optoelectronic devices.

  8. Evidence for a Novel Affinity Mechanism of Motor-assisted Transport Along MicrotubulesV⃞

    PubMed Central

    Wada, Yuuko; Hamasaki, Toshikazu; Satir, Peter

    2000-01-01

    In microtubule (MT) translocation assays, using colloidal gold particles coupled to monoclonal tubulin antibodies to mark positions along MTs, we found that relative motion is possible between the gold particle and an MT, gliding on dynein or kinesin. Such motion evidently occurred by an affinity release and rebinding mechanism that did not require motor activity on the particle. As the MTs moved, particles drifted to the trailing edge of the MT and then were released. Sometimes the particles transferred from one MT to another, moving orthogonally. Although motion of the particles was uniformly rearward, movement was toward the (−) or (+) end of the MT, depending on whether dynein or kinesin, respectively, was used in the assay. These results open possibilities for physiological mechanisms of organelle and other movement that, although dependent on motor-driven microtubule transport, do not require direct motor attachment between the organelle and the microtubule. Our observations on the direction of particle drift and time of release may also provide confirmation in a dynamic system for the conclusion that β tubulin is exposed at the (+) end of the MT. PMID:10637299

  9. Synthesis of nanostructured and microstructured ZnO and Zn(OH)2 on activated carbon cloth by hydrothermal and microwave-assisted chemical bath deposition methods

    NASA Astrophysics Data System (ADS)

    Mosayebi, Elham; Azizian, Saeid; Hajian, Ali

    2015-05-01

    Nanostructured and microstructured ZnO and Zn(OH)2 loaded on activated carbon cloth were synthesized by microwave-assisted chemical bath deposition and hydrothermal methods. By hydrothermal method the deposited sample on carbon fiber is pure ZnO with dandelion-like nanostructures. By microwave-assisted chemical bath method the structure and composition of deposited sample depends on solution pH. At pH = 9.8 the deposited sample on carbon fiber is pure ZnO with flower-like microstructure; but at pH = 10.8 the sample is a mixture of ZnO and Zn(OH)2 with flower-like and rhombic microstructures, respectively. The mechanism of crystal grow by microwave-assisted chemical bath method was investigated by SEM method at both pH.

  10. The Effect of Active Student Responding during Computer-Assisted Instruction on Social Studies Learning by Students with Learning Disabilities

    ERIC Educational Resources Information Center

    Jerome, Annamaria; Barbetta, Patricia M.

    2005-01-01

    An alternating treatments design with a best treatments phase was used to compare two active student response (ASR) conditions and one on-task (OT) condition on the acquisition and maintenance of social studies facts during computer-assisted instruction. Each week for six weeks, five students were provided daily computer-assisted instruction on 21…

  11. Gamma Band Activity in the RAS-intracellular mechanisms

    PubMed Central

    Garcia-Rill, E.; Kezunovic, N.; D’Onofrio, S.; Luster, B.; Hyde, J.; Bisagno, V.; Urbano, F.J.

    2014-01-01

    Gamma band activity participates in sensory perception, problem solving, and memory. This review considers recent evidence showing that cells in the reticular activating system (RAS) exhibit gamma band activity, and describes the intrinsic membrane properties behind such manifestation. Specifically, we discuss how cells in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine Subcoeruleus nucleus dorsalis (SubCD) all fire in the gamma band range when maximally activated, but no higher. The mechanisms involve high threshold, voltage-dependent P/Q-type calcium channels or sodium-dependent subthreshold oscillations. Rather than participating in the temporal binding of sensory events as in the cortex, gamma band activity in the RAS may participate in the processes of preconscious awareness, and provide the essential stream of information for the formulation of many of our actions. We address three necessary next steps resulting from these discoveries, an intracellular mechanism responsible for maintaining gamma band activity based on persistent G-protein activation, separate intracellular pathways that differentiate between gamma band activity during waking vs during REM sleep, and an intracellular mechanism responsible for the dysregulation in gamma band activity in schizophrenia. These findings open several promising research avenues that have not been thoroughly explored. What are the effects of sleep or REM sleep deprivation on these RAS mechanisms? Are these mechanisms involved in memory processing during waking and/or during REM sleep? Does gamma band processing differ during waking vs REM sleep after sleep or REM sleep deprivation? PMID:24309750

  12. A biomimetic pathway for vanadium-catalyzed aerobic oxidation of alcohols: evidence for a base-assisted dehydrogenation mechanism.

    PubMed

    Wigington, Bethany N; Drummond, Michael L; Cundari, Thomas R; Thorn, David L; Hanson, Susan K; Scott, Susannah L

    2012-11-19

    The first step in the catalytic oxidation of alcohols by molecular O(2), mediated by homogeneous vanadium(V) complexes [LV(V)(O)(OR)], is ligand exchange. The unusual mechanism of the subsequent intramolecular oxidation of benzyl alcoholate ligands in the 8-hydroxyquinolinato (HQ) complexes [(HQ)(2)V(V)(O)(OCH(2)C(6)H(4)-p-X)] involves intermolecular deprotonation. In the presence of triethylamine, complex 3 (X = H) reacts within an hour at room temperature to generate, quantitatively, [(HQ)(2)V(IV)(O)], benzaldehyde (0.5 equivalents), and benzyl alcohol (0.5 equivalents). The base plays a key role in the reaction: in its absence, less than 12% conversion was observed after 72 hours. The reaction is first order in both 3 and NEt(3), with activation parameters ΔH(≠)=(28±4) kJ mol(-1) and ΔS(≠)=(-169±4) J K(-1)  mol(-1). A large kinetic isotope effect, 10.2±0.6, was observed when the benzylic hydrogen atoms were replaced by deuterium atoms. The effect of the para substituent of the benzyl alcoholate ligand on the reaction rate was investigated using a Hammett plot, which was constructed using σ(p). From the slope of the Hammett plot, ρ=+(1.34±0.18), a significant buildup of negative charge on the benzylic carbon atom in the transition state is inferred. These experimental findings, in combination with computational studies, support an unusual bimolecular pathway for the intramolecular redox reaction, in which the rate-limiting step is deprotonation at the benzylic position. This mechanism, that is, base-assisted dehydrogenation (BAD), represents a biomimetic pathway for transition-metal-mediated alcohol oxidations, differing from the previously identified hydride-transfer and radical pathways. It suggests a new way to enhance the activity and selectivity of vanadium catalysts in a wide range of redox reactions, through control of the outer coordination sphere. PMID:23080554

  13. Providing training and technical assistance to customs officers and border guards: An effective mechanism to improve export controls

    SciTech Connect

    Gritton, C.A.

    1995-12-31

    With the disintegration of the Soviet Union, an increasing international concern requiring attention is illegal trafficking in nuclear and nuclear-related dual-use commodities. For the past few years, the US government, including the Department of Energy (DOE), has assisted the former Soviet Union in establishing and enhancing national export control systems. Although US assistance has been targeted to help control approved transfers, part of the focus has shifted to prevent the illegal exit of special nuclear material, dual-use items, and other nuclear-related materials. As part of a State Department initiative, a Nonproliferation and Disarmament Fund (NDF) was established to address various nonproliferation concerns. One project, funded by NDF, US Customs Service (Customs), and the DOE, focuses on assisting transit countries to prevent illegal trafficking. DOE is providing technical expertise to seven countries in the Baltics and Central Europe to help identify materials, equipment, and technology that might transit their borders. Although there are many mechanisms to prevent illegal trafficking, this paper will discuss the importance of providing international customs officials and border guards with training and technical assistance on nuclear materials and nuclear-related dual-use items. More specifically, detail of the DOE training plan will be discussed.

  14. Catalytic activity of noble metals for metal-assisted chemical etching of silicon

    PubMed Central

    2012-01-01

    Metal-assisted chemical etching of silicon is an electroless method that can produce porous silicon by immersing metal-modified silicon in a hydrofluoric acid solution without electrical bias. We have been studying the metal-assisted hydrofluoric acid etching of silicon using dissolved oxygen as an oxidizing agent. Three major factors control the etching reaction and the porous silicon structure: photoillumination during etching, oxidizing agents, and metal particles. In this study, the influence of noble metal particles, silver, gold, platinum, and rhodium, on this etching is investigated under dark conditions: the absence of photogenerated charges in the silicon. The silicon dissolution is localized under the particles, and nanopores are formed whose diameters resemble the size of the metal nanoparticles. The etching rate of the silicon and the catalytic activity of the metals for the cathodic reduction of oxygen in the hydrofluoric acid solution increase in the order of silver, gold, platinum, and rhodium. PMID:22738277

  15. Catalytic activity of noble metals for metal-assisted chemical etching of silicon

    NASA Astrophysics Data System (ADS)

    Yae, Shinji; Morii, Yuma; Fukumuro, Naoki; Matsuda, Hitoshi

    2012-06-01

    Metal-assisted chemical etching of silicon is an electroless method that can produce porous silicon by immersing metal-modified silicon in a hydrofluoric acid solution without electrical bias. We have been studying the metal-assisted hydrofluoric acid etching of silicon using dissolved oxygen as an oxidizing agent. Three major factors control the etching reaction and the porous silicon structure: photoillumination during etching, oxidizing agents, and metal particles. In this study, the influence of noble metal particles, silver, gold, platinum, and rhodium, on this etching is investigated under dark conditions: the absence of photogenerated charges in the silicon. The silicon dissolution is localized under the particles, and nanopores are formed whose diameters resemble the size of the metal nanoparticles. The etching rate of the silicon and the catalytic activity of the metals for the cathodic reduction of oxygen in the hydrofluoric acid solution increase in the order of silver, gold, platinum, and rhodium.

  16. Mechanical Activation of Construction Binder Materials by Various Mills

    NASA Astrophysics Data System (ADS)

    Fediuk, R. S.

    2016-04-01

    The paper deals with the mechanical grinding down to the nano powder of construction materials. During mechanical activation a composite binder active molecules cement minerals occur in the destruction of the molecular defects in the areas of packaging and breaking metastable phase decompensation intermolecular forces. The process is accompanied by a change in the kinetics of hardening of portland cement. Mechanical processes during grinding mineral materials cause, along with the increase in their surface energy, increase the Gibbs energy of powders and, respectively, their chemical activity, which also contributes to the high adhesion strength when contacting them with binders. Thus, the set of measures for mechanical activation makes better use of the weight of components filled with cement systems and adjust their properties. At relatively low cost is possible to provide a spectacular and, importantly, easily repeatable results in a production environment.

  17. [Ventricular assist device – Possibilities of long-term mechanical circulatory support].

    PubMed

    Englberger, Lars; Reineke, David C; Martinelli, Michele V; Mohacsi, Paul; Carrel, Thierry P

    2015-08-01

    In Switzerland 200’000 people suffer from congestive heart failure. Approximately 10’000 patients find themselves in an advanced state of the disease. When conservative treatment options are no longer available heart transplantation is the therapy of choice. Should this not be an option due to long waiting lists or medical issues assist device therapy becomes an option. Assist device therapy is separated in short-term and long-term support. Long-term support is nowadays performed with ventricular assist devices (VADs). The native heart is still in place and supported in parallel to the remaining function of the heart. The majority of patients are treated with a left ventricular assist device (LVAD). The right ventrical alone (RVAD) as well as bi-ventricular support (BiVAD) is rarely needed. The modern VADs are implantable and create a non-pulsative bloodflow. A percutaneous driveline enables energy supply and pump-control. Indication strategies for VAD implantations include bridge to transplant (short term support), bridge to candidacy and bridge to transplant. VADs become more and more a definite therapeutic option (destination therapy). VAD therapy might be a realistic alternative to organ transplantation in the near future. PMID:26227978

  18. Microwave-assisted activation for electroless nickel plating on PMMA microspheres

    NASA Astrophysics Data System (ADS)

    Chen, Yen-Chung; Liu, Robert Lian-Huey; Chen, Xin-Liang; Shu, Hsiou-Jeng; Ger, Ming-Der

    2011-05-01

    A novel microwave-assisted activation method for electroless plating on PMMA microspheres is presented in this study. When the microwave irradiation was applied during the activation step, the amount of the Pd species adsorbed on PMMA surfaces was much higher than that of sample pretreated with a conventional activation process without microwave irradiation. With this activation method, it was also shown that the adsorbed Pd species with a size of 4-6 nm were uniformly distributed on the surfaces of the PMMA microspheres, thus a smooth and uniform nickel-phosphorus coating on the PMMA microspheres was obtained by subsequent electroless plating. The samples after each step were characterized by XPS, TEM, ICP and SEM.

  19. Robot-assisted motor activation monitored by time-domain optical brain imaging

    NASA Astrophysics Data System (ADS)

    Steinkellner, O.; Wabnitz, H.; Schmid, S.; Steingräber, R.; Schmidt, H.; Krüger, J.; Macdonald, R.

    2011-07-01

    Robot-assisted motor rehabilitation proved to be an effective supplement to conventional hand-to-hand therapy in stroke patients. In order to analyze and understand motor learning and performance during rehabilitation it is desirable to develop a monitor to provide objective measures of the corresponding brain activity at the rehabilitation progress. We used a portable time-domain near-infrared reflectometer to monitor the hemodynamic brain response to distal upper extremity activities. Four healthy volunteers performed two different robot-assisted wrist/forearm movements, flexion-extension and pronation-supination in comparison with an unassisted squeeze ball exercise. A special headgear with four optical measurement positions to include parts of the pre- and postcentral gyrus provided a good overlap with the expected activation areas. Data analysis based on variance of time-of-flight distributions of photons through tissue was chosen to provide a suitable representation of intracerebral signals. In all subjects several of the four detection channels showed a response. In some cases indications were found of differences in localization of the activated areas for the various tasks.

  20. Mechanisms to enhance the effectiveness of allied health and social care assistants in community-based rehabilitation services: a qualitative study.

    PubMed

    Moran, Anna; Nancarrow, Susan A; Enderby, Pamela

    2015-07-01

    This research aims to describe the factors associated with successful employment of allied health and social care assistants in community-based rehabilitation services (CBRS) in England. The research involved the thematic analysis of interviews and focus groups with 153 professionally qualified and assistant staff from 11 older people's interdisciplinary community rehabilitation teams. Data were collected between November 2006 and December 2008. Assistants were perceived as a focal point for care delivery and conduits for enabling a service to achieve goals within interdisciplinary team structures. Nine mechanisms were identified that promoted the successful employment of assistants: (i) Multidisciplinary team input into assistant training and support; (ii) Ensuring the timely assessment of clients by qualified staff; (iii) Establishing clear communication structures between qualified and assistant staff; (iv) Co-location of teams to promote communication and skill sharing; (v) Removing barriers that prevent staff working to their full scope of practice; (vi) Facilitating role flexibility of assistants, while upholding the principles of reablement; (vii) Allowing sufficient time for client-staff interaction; (viii) Ensuring an appropriate ratio of assistant to qualified staff to enable sufficient training and supervision of assistants; and (ix) Appropriately, resourcing the role for training and reimbursement to reflect responsibility. We conclude that upholding these mechanisms may help to optimise the efficiency and productivity of assistant and professionally qualified staff in CBRS. PMID:25475506

  1. A Study of a Handrim-Activated Power-Assist Wheelchair Based on a Non-Contact Torque Sensor.

    PubMed

    Nam, Ki-Tae; Jang, Dae-Jin; Kim, Yong Chol; Heo, Yoon; Hong, Eung-Pyo

    2016-01-01

    Demand for wheelchairs is increasing with growing numbers of aged and disabled persons. Manual wheelchairs are the most commonly used assistive device for mobility because they are convenient to transport. Manual wheelchairs have several advantages but are not easy to use for the elderly or those who lack muscular strength. Therefore, handrim-activated power-assist wheelchairs (HAPAW) that can aid driving power with a motor by detecting user driving intentions through the handrim are being researched. This research will be on HAPAW that judge user driving intentions by using non-contact torque sensors. To deliver the desired motion, which is sensed from handrim rotation relative to a fixed controller, a new driving wheel mechanism is designed by applying a non-contact torque sensor, and corresponding torques are simulated. Torques are measured by a driving wheel prototype and compared with simulation results. The HAPAW prototype was developed using the wheels and a driving control algorithm that uses left and right input torques and time differences are used to check if the non-contact torque sensor can distinguish users' driving intentions. Through this procedure, it was confirmed that the proposed sensor can be used effectively in HAPAW. PMID:27509508

  2. 77 FR 71010 - Agency Information Collection Activities: Submission for OMB Review; Comment Request, Assistance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-28

    ... Review; Comment Request, Assistance to Firefighters Grant Program-Grant Application Supplemental...@dhs.gov . SUPPLEMENTARY INFORMATON: Collection of Information Title: Assistance to Firefighters...

  3. Voice-Activated Lightweight Reacher to Assist with Upper Extremity Movement Limitations: A Case Study.

    PubMed

    Khalid, Umer; Conti, Gerry E; Erlandson, Robert F; Ellis, Richard D; Brown, Vince; Pandya, Abhilash K

    2015-01-01

    The focus of this research was to design a functional and user-friendly reacher for people with spinal cord injuries (SCIs). Engineering advancements have taken assistive robotics to new dimensions. Technologies such as wheelchair robotics and myo-electronically controlled systems have opened up a wide range of new applications to assist people with physical disabilities. Similarly, exo-skeletal limbs and body suits have provided new foundations from which technologies can aid function. Unfortunately, these devices have issues of usability, weight, and discomfort with donning. The Smart Assistive Reacher Arm (SARA) system, developed in this research, is a voice-activated, lightweight, mobile device that can be used when needed. SARA was built to help overcome daily reach challenges faced by individuals with limited arm and hand movement capability, such as people with cervical level 5-6 (C5-6) SCI. This article shows that a functional reacher arm with voice control can be beneficial for this population. Comparison study with healthy participants and an SCI participant shows that, when using SARA, a person with SCI can perform simple reach and grasp tasks independently, without someone else's help. This suggests that the interface is intuitive and can be easily used to a high level of proficiency by a SCI individual. PMID:26132355

  4. Common mechanisms activate plant guard receptors and TLR4

    PubMed Central

    Kagan, Jonathan C.

    2014-01-01

    In metazoans, the innate immune system uses Pattern Recognition Receptors to detect conserved microbial products, whereas in plants Guard Receptors detect virulence factors or activities encoded by pathogens. In a recent study, Williams and colleagues report that plant Guard receptors can be activated by a mechanism remarkably similar to that of mammalian Toll-like Receptor 4. PMID:25224694

  5. Tractor Mechanics: Learning Activity Packages 1-19.

    ERIC Educational Resources Information Center

    Clemson Univ., SC. Vocational Education Media Center.

    Learning activity packages are presented for teaching tractor mechanics. The first of two sections deals with miscellaneous tasks and contains learning activity packages on cleaning the tractor and receiving new tractor parts. Section 2 is concerned with maintaining and servicing the electrical system, and it includes the following learning…

  6. Molecular Mechanism of Active Zone Organization at Vertebrate Neuromuscular Junctions

    PubMed Central

    Nishimune, Hiroshi

    2013-01-01

    Organization of presynaptic active zones is essential for development, plasticity, and pathology of the nervous system. Recent studies indicate a trans-synaptic molecular mechanism that organizes the active zones by connecting the pre- and the postsynaptic specialization. The presynaptic component of this trans-synaptic mechanism is comprised of cytosolic active zone proteins bound to the cytosolic domains of voltage-dependent calcium channels (P/Q-, N-, and L-type) on the presynaptic membrane. The postsynaptic component of this mechanism is the synapse organizer (laminin β2) that is expressed by the postsynaptic cell and accumulates specifically on top of the postsynaptic specialization. The pre- and the postsynaptic components interact directly between the extracellular domains of calcium channels and laminin β2 to anchor the presynaptic protein complex in front of the postsynaptic specialization. Hence, the presynaptic calcium channel functions as a scaffolding protein for active zone organization and as an ion-conducting channel for synaptic transmission. In contrast to the requirement of calcium influx for synaptic transmission, the formation of the active zone does not require the calcium influx through the calcium channels. Importantly, the active zones of adult synapses are not stable structures and require maintenance for their integrity. Furthermore, aging or diseases of the central and peripheral nervous system impair the active zones. This review will focus on the molecular mechanisms that organize the presynaptic active zones and summarize recent findings at the neuromuscular junctions and other synapses. PMID:22135013

  7. [Technical aspects of mechanical insufflator-exsufflators. Construction and function of the Emerson CoughAssist].

    PubMed

    Bosch, A; Winterholler, M

    2008-03-01

    The electromechanical insufflator-exsufflator (Emerson CoughAssist) was developed as an aid for patients with neuromuscular disorders suffering from impaired cough. The insufflator-exsufflator simulates and supports physiological cough by supporting inspiration with positive pressure and shifting this positive pressure rapidly into a negative pressure that supports exsufflation and thus bronchial clearance. Maximum pressures are +/- 60 cm H2O, pressures between 30 and 50 cm H2O are sufficient to produce assisted cough in adults with neuromuscular disease. The pressure shift from positive to negative occurs with 0.02 sec and is regulated by a magnetic valve. An anaesthetic facemask is used as interface, alternatively, a mouthpiece can be used in combination with a nose strap. It is also possible to use the insufflator-exsufflator in patients with tracheostomy. We present in this article detailed information about the technical principles and practical use of the electromechanical insufflator-exsufflator. PMID:18317985

  8. Fracture mechanics and surface chemistry investigations of environment-assisted crack growth

    NASA Technical Reports Server (NTRS)

    Wei, R. P.; Klier, K.; Simmons, G. W.; Chou, Y. T.

    1984-01-01

    It is pointed out that environment-assisted subcritical crack growth in high-strength steels and other high-strength alloys (particularly in hydrogen and in hydrogenous environments) is an important technological problem of long standing. This problem is directly related to issues of structural integrity, durability, and reliability. The terms 'hydrogen embrittlement' and 'stress corrosion cracking' have been employed to describe the considered phenomenon. This paper provides a summary of contributions made during the past ten years toward the understanding of environmentally assisted crack growth. The processes involved in crack growth are examined, and details regarding crack growth and chemical reactions are discussed, taking into account crack growth in steels exposed to water/water vapor, the effect of hydrogen, reactions involving hydrogen sulfide, and aspects of fracture surface morphology and composition. Attention is also given to the modeling of crack growth response, crack growth in gas mixtures, and the interaction of solute atoms with the crack-tip stress field.

  9. Health-Promoting Physical Activity of Children Who Use Assistive Mobility Devices: A Scoping Review.

    PubMed

    Jirikowic, Tracy L; Kerfeld, Cheryl I

    2016-01-01

    Children with physical disabilities who use assistive mobility devices (AMDs) are at risk for obesity and other secondary health conditions. Habitual physical activity is one lifestyle factor that may prevent obesity and contribute to overall health, and an active lifestyle in childhood improves prospects for lifelong healthy behaviors. Child, family, and environmental facilitators and barriers influence health-promoting physical activity (HPPA) for children without disabilities, but comparable models and levels of understanding for children who use AMDs are lacking. In this scoping review, we identified a similar set of child, family, and environmental facilitators and barriers relevant to HPPA participation among children who use AMDs. Noted gaps in the literature included limited reporting of AMD use, inconsistent HPPA definitions, and inadequate measurement tools for children who are nonambulatory. The identified child, family, and environmental factors provide a framework for occupational therapy practitioners and interprofessional teams to develop HPPA opportunities and interventions for an underserved population. PMID:27548861

  10. The Potential Applications of Peroxisome Proliferator-Activated Receptor δ Ligands in Assisted Reproductive Technology

    PubMed Central

    Huang, Jaou-Chen

    2008-01-01

    Peroxisome proliferator-activated receptor δ (PPARδ, also known as PPARβ) has ubiquitous distribution and extensive biological functions. The reproductive function of PPARδ was first revealed in the uterus at the implantation site. Since then, PPARδ and its ligand have been discovered in all reproductive tissues, including the gametes and the preimplantation embryos. PPARδ in preimplantation embryos is normally activated by oviduct-derived PPARδ ligand. PPARδ activation is associated with an increase in embryonic cell proliferation and a decrease in programmed cell death (apoptosis). On the other hand, the role of PPARδ and its ligand in gamete formation and function is less well understood. This review will summarize the reproductive functions of PPARδ and project its potential applications in assisted reproductive technology. PMID:19096716

  11. Recognition of user's activity for adaptive cooperative assistance in robotic surgery.

    PubMed

    Nessi, Federico; Beretta, Elisa; Ferrigno, Giancarlo; De Momi, Elena

    2015-01-01

    During hands-on robotic surgery it is advisable to know how and when to provide the surgeon with different assistance levels with respect to the current performed activity. Gesteme-based on-line classification requires the definition of a complete set of primitives and the observation of large signal percentage. In this work an on-line, gesteme-free activity recognition method is addressed. The algorithm models the guidance forces and the resulting trajectory of the manipulator with 26 low-level components of a Gaussian Mixture Model (GMM). Temporal switching among the components is modeled with a Hidden Markov Model (HMM). Tests are performed in a simplified scenario over a pool of 5 non-surgeon users. Classification accuracy resulted higher than 89% after the observation of a 300 ms-long signal. Future work will address the use of the current detected activity to on-line trigger different strategies to control the manipulator and adapt the level of assistance. PMID:26737482

  12. Microwave-assisted extraction of polysaccharides from Yupingfeng powder and their antioxidant activity

    PubMed Central

    Wang, Dan; Zhang, Bi-Bo; Qu, Xiao-Xia; Gao, Feng; Yuan, Min-Yong

    2015-01-01

    Background: Microwave-assisted reflux extraction of polysaccharides YPF-P from the famous Chinese traditional drug, Yupingfeng powder, optimization of extracting conditions and evaluation of their antioxidant activity were conducted in this study. Results: Single factor effect trends were achieved through yields and contends of YPF-P obtained from different extracting conditions. Then through a three-level, four-variable Box-Behnken design of response surface methodology adopting yield as response, the optimal conditions were determined as follows: Material/solvent ratio 1:23.37, microwave power 560 W, Extraction temperature 64°C, and extraction time 9.62 min. Under the optimal conditions, the YPF-P extraction yield was 3.23%, and its content was detected as 38.52%. In antioxidant assays, the YPF-P was tested to possess 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities with an IC50 value of 0.262 mg/ml. In addition, YPF-P was also proved to have relatively low ferric reducing antioxidant power (FRAP), compared to Vc, through FRAP assay. Conclusion: In the microwave assisted reflux extraction research, good YPF-P yield was achieved from materials with relatively low YPF-P content. And for the first time, both DPPH and FRAP assays were conducted on YPF-P, which proved that the antioxidant activity of YPF-P contributed to the functions of this medicine. PMID:26246730

  13. User-centric design of a personal assistance robot (FRASIER) for active aging.

    PubMed

    Padir, Taşkin; Skorinko, Jeanine; Dimitrov, Velin

    2015-01-01

    We present our preliminary results from the design process for developing the Worcester Polytechnic Institute's personal assistance robot, FRASIER, as an intelligent service robot for enabling active aging. The robot capabilities include vision-based object detection, tracking the user and help with carrying heavy items such as grocery bags or cafeteria trays. This work-in-progress report outlines our motivation and approach to developing the next generation of service robots for the elderly. Our main contribution in this paper is the development of a set of specifications based on the adopted user-centered design process, and realization of the prototype system designed to meet these specifications. PMID:26737419

  14. Water-plasma-assisted synthesis of black titania spheres with efficient visible-light photocatalytic activity.

    PubMed

    Panomsuwan, Gasidit; Watthanaphanit, Anyarat; Ishizaki, Takahiro; Saito, Nagahiro

    2015-06-01

    Black titania spheres (H-TiO2-x) were synthesized via a simple green method assisted by water plasma at a low temperature and atmospheric pressure. The in situ production of highly energetic hydroxyl and hydrogen species from water plasma are the prominent factors in the oxidation and hydrogenation reactions during the formation of H-TiO2-x, respectively. The visible-light photocatalytic activity toward the dye degradation of H-TiO2-x can be attributed to the synergistic effect of large-surface area, visible-light absorption and the existence of oxygen vacancies and Ti(3+) sites. PMID:25946395

  15. Theoretical study of thermally activated magnetization switching under microwave assistance: Switching paths and barrier height

    NASA Astrophysics Data System (ADS)

    Suto, H.; Kudo, K.; Nagasawa, T.; Kanao, T.; Mizushima, K.; Sato, R.; Okamoto, S.; Kikuchi, N.; Kitakami, O.

    2015-03-01

    Energy barrier height for magnetization switching is theoretically studied for a system with uniaxial anisotropy in a circularly polarized microwave magnetic field. A formulation of the Landau-Lifshitz-Gilbert equation in a rotating frame introduces an effective energy that includes the effects of both the microwave field and static field. This allows the effective-energy profiles to rigorously describe the switching paths and corresponding barrier height, which govern thermally activated magnetization switching under microwave assistance. We show that fixed points and limit cycles in the rotating frame lead to various switching paths and that under certain conditions, switching becomes a two-step process with an intermediate state.

  16. [Elucidation of the mechanism of fertilization and clinical application of assisted reproductive technology].

    PubMed

    Hiroi, M

    1996-08-01

    Fertilization is the process including many events such as maturation of egg and sperm, attachment, binding, acrosomal reaction, penetration, fusion, cortical reaction, zona reaction and nuclear fusion of both gamete, whereby individual gametes from the female and male unite to create offspring. Although the reason for mechanism of fertilization is still not clearly understood, this process may accelerate the rate adaptation in evolution. In this special lecture, I would like to present our experimental and clinical results especially concerning with morphological, physiological, biochemical and molecular approach on the mechanism of fertilization. 1. Development and maturation of follicles and oocytes. It is well known that pituitary FSH, LH control the ovarian function. Follicular development and ovum maturation are also controlled by both pituitary gonadotropins and local factors such as autocrine and paracrine agents. When hMG is injected during 1-6 day of menstrual cycle, several dominant follicles are developed. If hMG is injected after selection of dominant follicles, only one dominant follicle develop in the ovary. When PMS-treated immature rats were injected with immature or mature follicle fluids, rats injected with mature follicular fluid showed strongly suppress in the ovarian weights and numbers of ovulated follicles. Also mature follicle suppress aromatization from and androstenedione to estradiol. These findings mean that mature follicular fluid contains inhibitory factors. Apoptosis of granulosa cells and follicular steroids are related to fertilization. 2. Intracellular calcium of oocyte. Intracellular calcium concentration is known to start to increase in a periodic manner after fertilization in oocytes of mammalians. In 65% of tested mouse oocytes, fertilization occurred during 4 hours observation after sperm insemination in vitro. An initial long lasting intracellular calcium concentration was observed and followed by periodic manner. This

  17. Application of flexure structures to active and adaptive opto-mechanical mechanisms

    NASA Astrophysics Data System (ADS)

    Zago, Lorenzo; Genequand, Pierre M.; Kjelberg, Ivar; Morschel, Joseph

    1997-03-01

    Active and adaptive structures, also commonly called 'smart' structures, combine in one integrated system various functions such as load carrying and structural function, mechanical (cinematic) functions, sensing, control and actuating. Originally developed for high accuracy opto-mechanical applications, CSEM's technology of flexure structures and flexible mechanisms is particularly suited to solve many structural and mechanical issues found in such active/adaptive mechanisms. The paper illustrates some recent flexure structures developments at CSEM and outlines the comprehensive know-how involved in this technology. This comprises in particular the elaboration of optimal design guidelines, related to the geometry, kinematics and dynamics issues (for instance, the minimization of spurious high frequency effects), the evaluation and predictability of all performance quantities relevant to the utilization of flexure structures in space (reliability, fatigue, static and dynamic modeling, etc.). material issues and manufacturing procedures.

  18. Development of a Smartphone Application to Measure Physical Activity Using Sensor-Assisted Self-Report

    PubMed Central

    Dunton, Genevieve Fridlund; Dzubur, Eldin; Kawabata, Keito; Yanez, Brenda; Bo, Bin; Intille, Stephen

    2013-01-01

    Introduction: Despite the known advantages of objective physical activity monitors (e.g., accelerometers), these devices have high rates of non-wear, which leads to missing data. Objective activity monitors are also unable to capture valuable contextual information about behavior. Adolescents recruited into physical activity surveillance and intervention studies will increasingly have smartphones, which are miniature computers with built-in motion sensors. Methods: This paper describes the design and development of a smartphone application (“app”) called Mobile Teen that combines objective and self-report assessment strategies through (1) sensor-informed context-sensitive ecological momentary assessment (CS-EMA) and (2) sensor-assisted end-of-day recall. Results: The Mobile Teen app uses the mobile phone’s built-in motion sensor to automatically detect likely bouts of phone non-wear, sedentary behavior, and physical activity. The app then uses transitions between these inferred states to trigger CS-EMA self-report surveys measuring the type, purpose, and context of activity in real-time. The end of the day recall component of the Mobile Teen app allows users to interactively review and label their own physical activity data each evening using visual cues from automatically detected major activity transitions from the phone’s built-in motion sensors. Major activity transitions are identified by the app, which cues the user to label that “chunk,” or period, of time using activity categories. Conclusion: Sensor-driven CS-EMA and end-of-day recall smartphone apps can be used to augment physical activity data collected by objective activity monitors, filling in gaps during non-wear bouts and providing additional real-time data on environmental, social, and emotional correlates of behavior. Smartphone apps such as these have potential for affordable deployment in large-scale epidemiological and intervention studies. PMID:24616888

  19. Cellular and Molecular Mechanisms Underpinning Macrophage Activation during Remyelination

    PubMed Central

    Lloyd, Amy F.; Miron, Veronique E.

    2016-01-01

    Remyelination is an example of central nervous system (CNS) regeneration, whereby myelin is restored around demyelinated axons, re-establishing saltatory conduction and trophic/metabolic support. In progressive multiple sclerosis, remyelination is limited or fails altogether which is considered to contribute to axonal damage/loss and consequent disability. Macrophages have critical roles in both CNS damage and regeneration, such as remyelination. This diverse range in functions reflects the ability of macrophages to acquire tissue microenvironment-specific activation states. This activation is dynamically regulated during efficient regeneration, with a switch from pro-inflammatory to inflammation-resolution/pro-regenerative phenotypes. Although, some molecules and pathways have been implicated in the dynamic activation of macrophages, such as NFκB, the cellular and molecular mechanisms underpinning plasticity of macrophage activation are unclear. Identifying mechanisms regulating macrophage activation to pro-regenerative phenotypes may lead to novel therapeutic strategies to promote remyelination in multiple sclerosis. PMID:27446913

  20. Active vibration control using mechanical and electrical analogies

    NASA Astrophysics Data System (ADS)

    Torres-Perez, A.; Hassan, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Mechanical-electrical analogous circuit models are widely used in electromechanical system design as they represent the function of a coupled electrical and mechanical system using an equivalent electrical system. This research uses electrical circuits to establish a discussion of simple active vibration control principles using two scenarios: an active vibration isolation system and an active dynamic vibration absorber (DVA) using a voice coil motor (VCM) actuator. Active control laws such as gain scheduling are intuitively explained using circuit analysis techniques. Active vibration control approaches are typically constraint by electrical power requirements. The electrical analogous is a fast approach for specifying power requirements on the experimental test platform which is based on a vibration shaker that provides the based excitation required for the single Degree- of-Freedom (1DoF) vibration model under study.

  1. Pulmonary arterioplasty using video-assisted thoracic surgery mechanical suture technique

    PubMed Central

    Xu, Xin; Huang, Jun; Yin, Weiqiang; Zhang, Xin; Chen, Hanzhang; Mo, Lili

    2016-01-01

    Lung cancer invading pulmonary trunk is a locally advanced condition, which may indicate poor prognosis. Surgical resection of the lesion can significantly improve survival for some patients. Lobectomy/Pneumonectomy with pulmonary arterioplasty via thoracotomy were generally accepted and used in the past. As the rapid development of minimally invasive techniques and devices, pulmonary arterioplasty is feasible via video-assisted thoracic surgery (VATS). However, few studies have reported the VATS surgical techniques. In this study, we reported the techniques of pulmonary arterioplasty via VATS. PMID:27076961

  2. [The use of assistive technology in the daily activities of children with disabilities].

    PubMed

    Varela, Renata Cristina Bertolozzi; Oliver, Fátima Corrêa

    2013-06-01

    The scope of this study is to understand the use of assistive technology in the everyday life of children with disabilities, based on the concept of everyday life as a space for expression of particularity and generality of individuals. It was developed from documentary research of medical records, application of a form, observation of daily activities of children and their families and semi-structured interviews. Five children were studied, representatives in age, sex, diagnosis and use of technological resources, who were attended in primary healthcare units in São Paulo. The resources are used in homes, schools and other environments and their use is influenced by family and social relations and by the possibility of accessing products and services. It was established that the everyday activities and the use of resources are organized according to the time, space, ways in which children and, mainly, their caregivers act, showing the presence of pragmatism, economy and spontaneity typical of everyday life. The results revealed elements that can guide the practice of professionals working with assistive technology and can contribute to enable the appraisal of providing equipment in the Unified Health System. PMID:23752543

  3. Cellulase-assisted extraction and antibacterial activity of polysaccharides from the dandelion Taraxacum officinale.

    PubMed

    Wang, Hong-Bin

    2014-03-15

    In the present study, we investigated the cellulase-assisted extraction and antibacterial activity of water-soluble polysaccharides from the dandelion Taraxacum officinale. The extraction conditions, optimized for improving yield, were as follows: time, 46.11 min; temperature, 54.87 °C; pH, 4.51 and cellulase enzyme, 4000 U/g. Under these conditions, the yield of polysaccharides from dandelion (PD) reached 20.67% (w/w). The sugar content of PD was 95.6% (w/w), and it displayed high antibacterial activity at a concentration of 100mg/mL against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. These results indicate that PD may be a viable option for use as a food preservative. PMID:24528711

  4. Microwave-assisted, one-pot syntheses and fungicidal activity of polyfluorinated 2-benzylthiobenzothiazoles.

    PubMed

    Huang, Wei; Yang, Guang-Fu

    2006-12-15

    Polyfluorinated 2-benzylthiobenzothiazoles 3a-l are prepared via a microwave-assisted, one-pot procedure. The advantages, such as good to excellent yields, shorter reaction time (14-21min), readily available starting material, and simple purification procedure, distinguish the present protocol from other existing methods used for the synthesis of 2-benzylthiobenzothiazoles. Bioassay indicated that most of the compounds showed significant fungicidal activity against Rhizoctonia solani, Botrytis cinereapers, and Dothiorella gregaria at a dosage of 50microg/mL. Interestingly, compared to the control of commercial fungicide, triadimefon, compound 3c exhibited much higher activities against R. solani, B. cinereapers, and D. gregaria, which showed that the polyfluorinated 2-benzylthiobenzothiazoles can be used as lead compound for developing novel fungicides. PMID:17008103

  5. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration.

    PubMed

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  6. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    PubMed Central

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  7. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    NASA Astrophysics Data System (ADS)

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.

  8. Modulation of bone remodeling via mechanically activated ion channels

    NASA Technical Reports Server (NTRS)

    Duncan, Randall L. (Principal Investigator)

    1996-01-01

    A critical factor in the maintenance of bone mass is the physical forces imposed upon the skeleton. Removal of these forces, such as in a weightless environment, results in a rapid loss of bone, whereas application of exogenous mechanical strain has been shown to increase bone formation. Numerous flight and ground-based experiments indicate that the osteoblast is the key bone cell influenced by mechanical stimulation. Aside from early transient fluctuations in response to unloading, osteoclast number and activity seem unaffected by removal of strain. However, bone formation is drastically reduced in weightlessness and osteoblasts respond to mechanical strain with an increase in the activity of a number of second messenger pathways resulting in increased anabolic activity. Unfortunately, the mechanism by which the osteoblast converts physical stimuli into a biochemical message, a process we have termed biochemical coupling, remains elusive. Prior to the application of this grant, we had characterized a mechanosensitive, cation nonselective channel (SA-cat) in osteoblast-like osteosarcoma cells that we proposed is the initial signalling mechanism for mechanotransduction. During the execution of this grant, we have made considerable progress to further characterize this channel as well as to determine its role in the osteoblastic response to mechanical strain. To achieve these goals, we combined electrophysiologic techniques with cellular and molecular biology methods to examine the role of these channels in the normal function of the osteoblast in vitro.

  9. EBSD-Assisted Slip Trace Analysis During In Situ SEM Mechanical Testing: Application to Unravel Grain Size Effects on Plasticity of Pure Mg Polycrystals

    NASA Astrophysics Data System (ADS)

    Cepeda-Jiménez, C. M.; Molina-Aldareguia, J. M.; Pérez-Prado, M. T.

    2016-01-01

    The aim of this paper is to highlight the unique capabilities of electron backscattered diffraction-assisted trace analysis during in situ SEM mechanical testing of metals in order to get a better understanding of plasticity at the microscale. The technique allows for the direct observation of different deformation mechanisms, such as slip and twinning activity, at the microscale. Moreover, and contrary to other methods, it can provide statistically sound evidence of the role of the local microstructure, such as the local texture and grain boundary network, on the activation of the different deformation modes. The power of the technique is demonstrated by reviewing recent work that has been key to solving several remaining controversies regarding the role of grain size, strain rate and temperature on the plasticity of Mg polycrystals. In particular, it was found that, with decreasing grain size, at room temperature, a clear transition from non-basal- to basal-slip-dominated flow takes place under tension and a transition from twinning to basal slip takes place under compression. On the other hand, a similar transition from twinning to basal slip takes place with increasing temperature and decreasing strain rate. The emergence of basal slip as a dominant mechanism is shown to be due to increasing levels of connectivity between favorably oriented grains, which facilitate slip transfer across grain boundaries.

  10. Small molecules reveal an alternative mechanism of Bax activation

    PubMed Central

    Brahmbhatt, Hetal; Uehling, David; Al-awar, Rima; Leber, Brian; Andrews, David

    2016-01-01

    The pro-apoptotic protein Bax commits a cell to death by permeabilizing the mitochondrial outer membrane (MOM). To obtain small-molecule probes for elucidating the molecular mechanism(s) of Bax activation, we screened for compounds that induced Bax-mediated liposome permeabilization. We identified five structurally different small molecules that promoted both Bax targeting to and oligomerization at membranes. All five compounds initiated Bax oligomerization in the absence of membranes by a mechanism unlike Bax activation by Bcl-2 homology 3 domain (BH3) proteins. Some of the compounds induced Bax/Bak-dependent apoptosis in cells. Activation of Bax by the most active compound was poorly inhibited by the anti-apoptotic protein Bcl-XL and requires a cysteine residue at position 126 of Bax that is not required for activation by BH3 proteins. Our results reveal a novel pathway for Bax activation independent of pro-apoptotic BH3 proteins that may have important implications for the regulation of Bax activity in cells. PMID:26916338