Presence Of Pressure Research Articles

Mismatch Between the Resting Membrane Potential and the Voltage at Maximum Amplification in Outer Hair Cells (OHCS) of Mammalian Cochlea

OHCs amplify sound by an electromechanical mechanism. Sound-induced vibrations cause OHC membrane potential (E) to change from its resting voltage (Em) to a new value (Em+dE). The induced receptor potential (dE) initiates charge movement (Q) and force production to counteract viscous losses incurred by the traveling wave. Q exhibits a sigmoidal function with E and because it is most sensitive to dE at the midpoint (Vm), Em should equal Vm to ensure maximum amplification. Vm was measured with isolated OHCs extracted from guinea pig with whole-cell patch clamp under constant intracellular pressure in presence of KCNQ4 blocker XE991 (≥ 30 μM) to ensure robust voltage clamp (conductance < 1.5 nS at Vm). After correcting for physiological conditions the results show Vm is coincident with in vitro measurements of Em (Neuron 2011 70: 1143), but a mismatch of 40 mV is apparent when comparing with in vivo measurements of Em made at basal (J. Physiol. 1987 383: 551 and Proc. R. Soc. Lond. B. 1992 247: 97) or apical (J. Neuroscience 1985 5: 1591) regions of cochlea. Results also reveal variation of Vm across the cochlea as a function of a non-uniform charge density of the lateral wall (σ); when σ is uniform Vm is constant, and when σ varies inversely with area of lateral wall (ALW)Vm increases monotonically from a hyperpolarized value at the high frequency region of cochlea to a depolarized value at low frequency region. Although the relationship between Vm and σ is satisfying as it reflects the electric field, the disparity between in vitro and in vivo measurements highlights the need to reconcile them to ascertain the operating position of the amplifier.

Catalytic hydroliquefaction of charcoal CCB (copper, chromium and boron)-treated wood for bio-oil production: Influence of CCB salts, residence time and catalysts

Thermochemical processes offer a feasible option for wood waste management and the recovery of a variety of useful chemicals. In this paper, hydroliquefaction with the use of catalysts was optimized to provide bio-oil from CCB-treated wood by reducing gaseous emissions of copper, chromium and boron (hazardous materials). In addition, the influence of CCB salts, catalysts (Al2O3, Na2CO3, MgO and CaCO3) and residence time on the hydroliquefaction process was investigated. For this, hydroliquefaction of charcoal obtained by slow pyrolysis of CCB-treated wood was conducted under hydrogen pressure in presence of tetralin. The results showed that CCB salts and catalysts increase the yield of bio-oil compared to hydroliquefaction of charcoal from untreated wood. It was also observed, that the use of catalysts improves the residence time during the process. Among the catalysts employed, Al2O3 appears to be the most effective. Furthermore Na2CO3 promotes the formation of gaseous species particularly CH4. Analyses of hazardous materials in charcoal residue (coke) illustrate their transfer to the bio-oil with the increase of bio-oil yield and residence time except when Al2O3 was using. The bio-oil obtained contains aromatic compounds.

Mobilization of the Obese Patient and Prevention of Injury

Obese patients are difficult to transport between emergency departments, imaging facilities, operating rooms, intensive care units, acute care units, and rehabilitation facilities. Each move, along with turning, bathing, and access to bathrooms, poses risks of injury to patients and personnel. Similarly, inadequate mobilization raises the risk of pressure ulcers. The costs can be prohibitive. On 6 pilot units, mobilization of patients was delegated to trained lift team technicians who covered the units in pairs, 24 hours per day, 7 days per week, to assist with moving and lifting of patients weighing 200 pounds or more, with a Braden Scale score of 18 or less and/or the presence of pressure ulcers. In fiscal year 2012, hospital-acquired pressure ulcers on pilot units decreased by 43% (from 61 to 35). Patient handling-related employee injuries on pilot units decreased by 38.5% (from 13 to 8). Employee satisfaction related to organizational commitment to employee safety and impact on job satisfaction was positively impacted by implementation of the lift team. With the reduction in employee injuries and the fall in the prevalence of pressure ulcers, the adoption of the lift team program decreased costs by $493,293.00. Implementation of lift teams on pilot nursing units decreased patient handling-related employee injuries, resulting in sharp improvements in quality patient care and reduced costs.

The effect of pressure on high‐ and low‐working‐memory students: An elaboration of the choking under pressure hypothesis

Fifty-three third and fourth graders from China participated in this study. Participants' working memory (WM) was assessed by the Automated Operation Span task. Then, they solved mental addition problems of different types under low- and high-pressure conditions. Performance was analysed as a function of pressure condition, working memory capacity, and problem type. On 'no carry' mental addition problems, there was no difference between the two groups of children regardless the presence of pressure. For problems with carries, low WM (LWM) children performed worse on all tasks compared with high WM (HWM) children in the no-pressure condition, but pressure influenced the LWM and HWM differently depending on the nature of the carrying task. On 'hidden carry' mental addition trials (for which guessing strategies were minimally effective), LWM performance was much lower than HWM performance under pressure. By contrast, performance was similar between LWM and HWM groups under pressure on the 'normal carry' trials that allowed for non-resource-intensive heuristic strategies. Whether high- or low-working-memory elementary-school-aged children were more or less affected by pressure was dependent on task-difficulty and the types of strategies that could be used to solve the problems.

La validez y la eficacia de los ejercicios respiratorios para reducir la ansiedad escénica en el aula de música

This paper reviews the most relevant literature in the field of stage fright associated with musical performance, both in adulthood as in childhood. It also presents the findings of studies that have analyzed this feature of personality at schools and highlights the reasons causing stage fright, such as: pressure in presence of parents and other students, perfectionism, and low resistance to stress.On the other hand, this paper relates the development of stage fright with the loss of self-esteem, which affects child's education at large. Potential therapies that could be implemented in the classroom are discussed in order to cope with this anxiety. Breath techniques are the most important strategies because of their efficiency and ease of application. Finally, a Decalogue is established as a guide for action to combat performance anxiety which generalist and music teachers could take into account ahead of a first play at schools.

Resilient actions in the diagnostic process and system performance

ObjectivesSystemic issues can adversely affect the diagnostic process. Many system-related barriers can be masked by ‘resilient’ actions of frontline providers (ie, actions supporting the safe delivery of care in the...

Sonoenzymatic decolourization of an azo dye employing immobilized horse radish peroxidase (HRP): A mechanistic study

For degradation of biorefractory pollutants, enzymatic treatments and sonochemical treatments have shown high potential. A combined technique of sono-enzymatic treatment is of special interest as it has shown enhancement effect than the individual techniques. This work has attempted to give a mechanistic insight into the interaction of sonochemical and enzymatic treatments using immobilized horseradish peroxidase (HRP) enzyme on the decolourization of acid red dye (an azo dye). In order to segregate the effect of ultrasound and cavitation, experiments were conducted at elevated static pressure. The kinetic parameters of HRP, viz. Vmax and Km were marginally affected by immobilization. There was a minor change in pH optima and temperature optima for immobilized HRP (6.5, 25°C) from free HRP (7.0, 20–25°C). Though the specific activity of free enzyme (0.272U/mg) was found to be higher than the immobilized enzyme (0.104U/mg), immobilized enzyme exhibited higher stability (up to 3 cycles) and degradation potential than free enzyme in all experiments. The results revealed that the coupling of sonication and enzymatic treatment at high pressure in presence of polyethylene glycol (PEG) yielded the highest decolourization of acid red (61.2%). However, the total decolourization achieved with combined technique was lesser than the sum of individual techniques, indicating negative synergy between the sonochemical and enzymatic techniques.

Hypervelocity Cavity Expansion in Porous Elastoplastic Solids

Dynamic steady-state spherical cavitation fields are examined with emphasis on material porosity at large strain. Cavity expansion is driven by constant internal pressure in presence of remote tension or compression. The plastic branch of constitutive relations is described by the Gurson model, with arbitrary strain hardening. The mathematical model is reduced to a system of four ordinary nonlinear coupled differential equations. Numerical examples show that a plastic shock wave builds up as expansion velocity approaches a critical value and jump conditions across the shock are accounted for. At critical levels of remote tension, quasi-static cavitation of all internal voids is induced before dynamic cavity expansion occurs.

A detailed model for discharge initiation in argon at atmospheric pressure in presence of dielectric barriers

A detailed model was presented to explain the dielectric barrier effects employed to improve the insulation performance. The simulations were carried out for the dielectric barrier in two forms; as coating on electrodes, and as insertion in the inter-electrode gap. The electron conservation was modeled by the electron number density continuity equation using the drift-diffusion approximation. The analogous equation was applied for electron energy conservation. For diffusive transport modeling of heavy particles (including ions, excited atoms and ground state atoms), the mixture-averaged evaluation was formulated. The source terms were extracted based on plasma chemistry related to Argon including volumetric and surface reactions. The model is based upon a simultaneous solution of all foregoing equations together with the Poisson's equation. The simulation results for applying a standard lightning impulse voltage for both positive and negative polarities were presented and discussed. The impact of various parameters e.g. the thickness of the barrier, the position of the barrier, and the role of applied voltage polarity on insulation performance were simulated and analyzed.

Hydrostatic pressure on optical absorption and refractive index changes of a shallow hydrogenic impurity in a GaAs/GaAlAs quantum wire

The effect of hydrostatic pressure on the binding energy of a hydrogenic impurity in a GaAs/GaAlAs quantum wire is discussed. Calculations have been performed using Bessel functions as an orthonormal basis within a single band effective mass approximation. Pressure induced photoionization cross section of the hydrogenic impurity is investigated. The total optical absorption and the refractive index changes as a function of normalized photon energy between the ground and the first excited state in the presence of pressure are analysed. The optical absorption coefficients and the refractive index changes strongly depend on the incident optical intensity and the pressure.

The Movement Kinematics and Learning Strategies Associated with Adopting Different Foci of Attention during Both Acquisition and Anxious Performance

Research suggests that implicit strategies adopted during learning help prevent breakdown of automatic processes and subsequent performance decrements associated with the presence of pressure. According to the Constrained Action Hypothesis, automaticity of movement is promoted when adopting an external focus of attention. The purpose of the current experiment was to investigate if learning with an external focus of attention can enhance performance under subsequent pressure situations through promoting implicit learning and automaticity. Since previous research has generally used outcome measures of performance, the current study adopted measures of movement production. Specifically, we calculated within-subject variability in trajectory velocity and distance traveled every 10% of movement time. This detailed kinematic analysis allowed investigation into some of the previously unexplored mechanisms responsible for the benefits of adopting an external focus of attention. Novice participants performed a 2.5 m golf putt. Following a pre-test, participants were randomly assigned to one of three focus groups (internal, external, control). Participants then completed 400 acquisition trials over two consecutive days before being subjected to both a low anxiety and high anxiety (HA) transfer test. Dependent variables included variability, number of successful putts and mean radial error. Results revealed that variability was greater in the internal compared to the external and control groups. Putting performance revealed that all groups increased performance following acquisition. However, only the control group demonstrated a decrement in performance in the HA transfer test. These findings suggest that adopting an appropriate focus of attention during learning can prevent choking; with an external focus inhibiting the breakdown of automatic processes and an internal focus acting as a self-focus learning strategy and thus desensitizing individuals to anxiety effects.

A Study on the Combined Effect of Obesity and Load Carriage on Plantar Pressure Patterns of Primary School Children

From childhood, children are required daily to carry a load (necessary to perform their regular school activities) that is often beyond the limits established for adult workers. While some critical issues related to possible negative consequences in terms of postural alterations and onset of musculoskeletal diseases are well known and investigated, little information is available for the population of overweight and obese children, which appears to increase year after year. As their bodies are physiologically subject to a certain degree of overload, the addition of a supplemental load may induce further stress, the effects of which should be carefully evaluated. This study focuses on the foot-ground relationship, with special attention on plantar pressure distribution. The primary goal is to assess whether or not backpack presence alters in different ways the physiological pressure patterns in obese subjects compared with normal ones. To this end, 45 obese and overweight children (6-10 years old) and an equal sample of non-obese schoolmates matched for gender, age and height, were tested with a pressure platform to acquire the plantar pressure distribution in absence and presence of a backpack. Results show that the carried load induces similar increases in both groups, even though a significant shift of the center of pressure in presence of a backpack was found for obese female subjects. The very high pressure peaks observed in the obese population suggest that further studies are required to evaluate specific issues of the musculoskeletal system related to the combination of load carriage and obesity.

Pressure induced optical absorption and refractive index changes of a shallow hydrogenic impurity in a quantum wire

Pressure induced binding energy of a hydrogenic impurity in an InAs/GaAs quantum wire is investigated. Calculations are performed using Bessel functions as an orthonormal basis within a single band effective mass approximation using variational method. Photoionization cross-section of the hydrogenic impurity in the influence of pressure is studied. The total optical absorption and the refractive index changes as a function of normalized photon energy between the ground and the first excited state in the presence of pressure are analyzed. The optical absorption coefficients and the refractive index changes strongly depend on the incident optical intensity and pressure. The occurred blue shift of the resonant peak due to the pressure gives the information about the variation of two energy levels in the quantum well wire. The optical absorption coefficients and the refractive index changes are strongly dependent on the incident optical intensity and the pressure.

Analysis of statistical nature of electrical breakdown time delay in nitrogen at 6.6 mbar pressure in presence of positive ions and N(4S) atoms

AbstractOn the basis of the mean value of electrical breakdown time delay $ \overline t_d $ and the standard deviation of electrical breakdown time delay σ dependence on the afterglow period τ, the mechanisms which dominantly influence to breakdown initiation in nitrogen were separated. It was shown that the positive ions formed in mutual collision of long‐lived metastable molecules have a dominant role in breakdown initiation for τ values up to 70 ms. The metastable molecules were derived from previous breakdown and discharge. In this case σ ≪ td and the total time delay td is approximately equal to formative time tf which decreases in value with the increase of overvoltage. When positive ions have a dominant role in the breakdown initiation the Gaussian distribution describes data of td ≈ tf very well. For τ &gt; 1 s, N (4S) atoms formed in previous breakdown and discharge, have a dominant role in the breakdown initiation. Then, σ ≈$ \overline t_d $ and Laue's distribution, which is valid for statistical time delay ts, describes td data very well (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Pulse-reverse treatment of carbon nanomaterials for the electrochemical storage of energy

The paper dwells upon the investigation of carbon nanomaterials synthesized by an electric arc-method from methane-air mixture under atmospheric pressure in presence of Ni catalyst. These materials may be used for the electrochemical storage of energy. According to the data of transmission electron microscopy the carbon nanomaterials are generally represented by carbon nanotubes with the diameter of 20-80 nm. The pulse-reverse treatment of carbon nanomaterials in concentrated sulphuric electrolytes with addition of fluoride and lithium ions is carried out to increase their discharge capacity in 1 M H2SO4 and 1 M KOH. The properties of carbon nanomaterials are studied using the Brunauer-Emmett-Teller method, chemical energy-dispersive X-ray analysis, potentiostatic charge method of electrochemical saturation of hydrogen and potentiodynamic discharge method. The maximum discharge capacity of 940 C g−1 in 1 M H2SO4 is revealed for CNMs subjected to pulse-reverse treatment in concentrated sulphuric electrolyte containing fluoride and lithium ions.

P02-255 - The elderly over 90yr affected by deperession post-stroke respond well to antidepressant therapy with SSRI? study on a population admitted in nursing home (RSA)

IntroductionThe frailty of elderly in Tenth Decade with stroke was considered a certainty for many years ruling, and the stroke in 90 year old was a paradigm of fragility in gerontology. However soon enough the existing data on the population in nursing homes.MethodThe aim of this study was to evaluate the response to therapy SSRI antidepressants (fluoxetine 20–40 mg; sertraline 25–100 mg,; citalopram 10–40 mg) in a population of olds with depression after-stroke hospitalized in Nursing Home (RSA) at Catania (Sicily). We evaluated a total sample of 66 patients comparing the 13 patients 90yr-old with the 53 patients younger pertaining to the same RSA for stroke.ResultsStackable with somatic comorbidity and the post-stroke depression between the two populations, we founded:1.Both populations are responsive to antidepressant treatment with SSRIs2.The ninety recover more and more 'rapid cognitive impairment3.Both Populations improves the performances with rehabilitation recovering functional self-autonomy, albeit from different levels.4.The nutrient levels overlap in both populations and increased fragility biological of over 90-year old is evident for among of Prevalence and incidence of Delirium and Presence of Pressure Sores.ConclusionAccording to this data the response to antidepressants seems to be good and totally overlapped with the population most 'young studied as a reference.This data also confirms that it is not age itself but the comorbidity of diseases present that make it’ a frail old man and that probably the frailty of the nineties is a biological myth.

A novel method to predict the effect of static charges on the pull-in voltage and touch-point pressure of the capacitive transducer with square diaphragm

Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO2 and Si3N4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the diaphragm comes in contact with dielectric. The pressure at which diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, pull-in voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the pull-in voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the pull-in voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for pull-in voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.

Actividad inducida por androsterona y hemisuccinato de androsterona sobre la presión de perfusión y la resistencia vascular

Few data exist with respect to the effects of androsterone and their derivatives at cardiovascular level. In addition, the molecular mechanisms and cellular site of action of these androgens are still unclear. An evaluation was conducted on the effects induced by androsterone and hemisuccinate of androsterone on perfusion pressure and vascular resistance. The effects of both androsterone and hemisuccinate of androsterone on the perfusion pressure and vascular resistance in isolated rat hearts (Langendorff model) were evaluated. The results showed that: (1) the hemisuccinate of androsterone [10(-9) M] increases the perfusion pressure and vascular resistance in comparison with the androsterone [10(-9) M]; (2) the effect of androsterone-derivative [10(-9) M-10(-5) M] on perfusion pressure not was inhibited by indometacin [10(-6) M]; (3) nifedipine [10(-6) M] blocks the effects exerted by hemisuccinate of androsterone [10(-9) M-10(-5) M] on perfusion pressure; and (4) the effect of androsterone-derivative [10(-9) M-10(-5) M] on perfusion pressure in presence of flutamide [10(-6) M] was inhibited. The effects induced by androsterone and hemisuccinate of androsterone on the perfusion pressure and resistance vascular probably involve the interaction of steroid-receptor androgenic and, indirectly, activation of the calcium channel to induce variations in the perfusion pressure.

A density functional study of structural and elastic properties of LaN under high pressure

Structural and elastic properties of LaN at normal and high pressures are investigated using ab initio calculations based on full-potential linearized augmented plane wave (FP-LAPW) within both local density approximation (LDA) and generalized gradient approximation (GGA). Our results concerning equilibrium lattice parameter and bulk modulus agree well with the available experimental and previous theoretical findings. The transition pressure from NaCl (B1) to CsCl (B2) phase is found to be 31.05 GPa from LDA, and 42.2 GPa from GGA. To the best of our knowledge, the elastic properties for LaN in the B1 structure in the presence of pressure have never been reported so far. The linear pressure coefficients of elastic constants and their related bulk modulus are determined from the pressure dependence of these parameters. Furthermore, the mechanical stability criteria for LaN in B1 phase are found to be fulfilled at normal conditions.

Einstein’s gravity under pressure

The mysterious `dark energy' needed to explain the current observations, poses a serious confrontation between fundamental physics and cosmology. The present crisis may be an outcome of the (so far untested) prediction of the general theory of relativity that the pressure of the matter source also gravitates. In this view, a theoretical analysis reveals some surprising inconsistencies and paradoxes faced by the energy-stress tensor (in the presence of pressure) which is used to model the matter content of the universe, including dark energy.