Clinical Efficacy of Hyperbaric Oxygen Therapy at Different Pressures in the Treatment of Sudden Deafness

Objective:To analyze the efficacy of hyperbaric oxygen at different pressures in the treatment of sudden deafness.Methods:Eighty-two patients with sudden deafness treated in the Affiliated Hospital of Hebei University from September 2019 to September 2021 were selected as the research subjects.The patients were randomly divided into study group 1 and study group 2,and they were treated with hyperbaric oxygen on the basis of routine treatment,in which the pressure used was 1.8 ATA and 2.2 ATA,respectively.Oxygen was delivered via the pressure stabilizing mask for 60 minutes.The patients received two courses of treatment,each lasting 10 days.The changes in hearing(pure tone audiometry)and the clinical efficacy of both the groups were compared before and after treatment.The data obtained were statistically analyzed using SPSS 19.0.Results:The total effective rate of study group 1 was 90.00%,while that of study group 2 was 76.19%.The differences between the two groups were statistically significant(p<0.05).Conclusion:For patients with sudden deafness treated with hyperbaric oxygen,the clinical efficacy of 1.8 ATA is more significant than that of 2.2 ATA.

Observation on the Clinical Effect of Different Pressures in Hyperbaric Oxygen Therapy on Patients with Diffuse Axonal Injury

Objective:To observe the efficacy and significance of hyperbaric oxygen at different pressures in the treatment of diffuse axonal injury(DAI).Methods:Sixty patients with DAI were randomly divided into 1.8 ATA group(30 cases)and 2.2 ATA group(30 cases).The routine treatment for each group was the same.The 1.8 ATA.group received hyperbaric oxygen therapy under 1.8 ATA on the basis of routine treatment,whereas the 2.2 ATA group received hyperbaric oxygen therapy under 2.2 ATA.on the basis of routine treatment.The therapy was given once a day over 3 consecutive courses,with each course having 10 sessions.The Glasgow Coma Scale(GCS)on day 10,day 20,and day 30 after treatment,as well as the Glasgow Outcome Scale(GOS)after 6 months were compared between the two groups.Results:The mean GCS on day 10,day 20,and day 30 after treatment,as well as the mean GOS after 6 months of treatment in the 2.2 ATA group were significantly higher than those in the 1.8 ATA group(p<0.05).Conclusion:For patients with dififtise axonal injury,hyperbaric oxygen therapy is more effective with 2.2 ATA.compared with 1.8 ATA.

Differential pressure difference based altitude control of a stratospheric satellite

An autonomous altitude adjustment system for a stratospheric satellite(StratoSat)platform is proposed.This platform consists of a helium balloon,a ballonet,and a two-way blower.The helium balloon generates lift to balance the platform gravity.The two-way blower inflates and deflates the ballonet to regulate the buoyancy.Altitude adjustment is achieved by tracking the differential pressure difference(DPD),and a threshold switching strategy is used to achieve blower flow control.The vertical acceleration regulation ability is decided not only by the blower flow rate,but also by the designed margin of pressure difference(MPD).Pressure difference is a slow-varying variable compared with altitude,and it is adopted as the control variable.The response speed of the actuator to disturbance can be delayed,and the overshoot caused by the large inertia of the platform is inhibited.This method can maintain a high tracking accuracy and reduce the complexity of model calculation,thus improving the robustness of controller design.

Laser-Induced Graphite Plasma Kinetic Spectroscopy under Different Ambient Pressures

The laser induced plasma dynamics of graphite material are investigated by optical emission spectroscopy. Abla- tion and excitation of the graphite material is performed by using an 1064nm Nd：YAG laser in different ambient pressures. Characteristics of graphite spectra as line intensity variations and signal-to-noise ratio are presented with a main focus on the influence of the ambient pressure on the interaction of laser-induced graphite plasma with an ambient environment. Atomic emission lines are utilized to investigate the dynamical behavior of plasma, such as the excitation temperature and electron density, to describe emission differences under different ambient conditions. The excitation temperature and plasma electron density are the primary factors which contribute to the differences among the atomic carbon emission at different ambient pressures. Reactions between the plasma species and ambient gas, and the total molecular number are the main factors influencing molecular carbon emis- sion. The influence of laser energy on the plasma interaction with environment is also investigated to demonstrate the dynamical behavior of carbon species so that it can be utilized to optimize plasma fluctuations.

An Experimental Study on Atmospheric Pressure Glow Discharge in Different Gases

Usually, the electrical breakdown of dielectric barrier discharge (DBD) at atmo-spheric pressure leads to a filamentary non-homogeneous discharge. However, it is also possible to obtain a diffuse DBD in homogeneous form, called atmospheric pressure glow discharge (APGD). We obtained a uniform APGD in helium and in the mixture of argon with alcohol, and studied the electrical characteristics of helium APGD. It is found that the relationship between discharge current and source frequency is different depending on the difference in gas gap when the applied voltage is kept constant. The discharge current shows an increasing trend with the increased frequency when gas gap is 0.8 cm, but the discharge current tends to decrease with the increased frequency when the gas gap increases. The discharge current always increases with the increased applied voltage when the source frequency is kept constant. We also observed a glow-like discharge in nitrogen at atmospheric pressure.

Minor Pressure Differences within the Fontan-Anastomosis in Patients with Total Cavopulmonary Connection by 4D-Flow Magnetic Resonance Imaging

Background: Pressure measurement in total cavopulmonary connection (TCPC) patients is a domain of cardiaccatheterization. 4D velocity encoded cardiovascular magnetic resonance (4D–flow MRI) offers an alternative forassessment of even minor pressure differences. The scope of this study was to measure even minor pressure differencesin the anastomosis of TCPC patients, who are clinically uncompromised. Methods: Twenty-four patients(median 15 years [8;34]) with TCPC were studied prospectively by 4D-flow MRI. Pressure differences betweensuperior vena cava (SVC) and extracardiac conduit (C) to both right pulmonary artery (RPA) and left pulmonaryartery (LPA) were assessed. Small fluid obstructions as vortices within the anastomosis were detected by flowpathlines from 4D-flow MRI. In two patients pressure differences were calculated also by computational flowdynamics (CFD) as a plausibility check for the order of magnitude. Results: Median values of pressure differencesin the anastomosis between SVC and RPA were 0.63 (0.21–2.1) mmHg, between C and RPA 0.67 (0.3–2.2)mmHg, between SVC and LPA 0.8 (0.3–2.4) mmHg and between C and LPA 0.7 (0.2–1.9) mmHg. Patients withpotential flow obstruction (stents, occluder, vortices) had significantly higher gradients at the anastomosis (p <0.05) than patients without potential obstructions, although the absolute values were small. CFD- and measurement-based pressure difference showed good agreement. Conclusion: 4D-flow MRI is able to detect minor pressuredifferences within the Fontan circuit even in patients with apparently satisfactory TCPC. Slightly higherpressure differences are due to the presence of small flow obstruction.

Hydrocephalic cerebrospinal fluid flowing rotationally with pulsatile boundaries:A mathematical simulation of the thermodynamical approach

To study the kinematics of flow rate and ventricular dilatation,an analytical perturbation approach of hydrocephalus has been devised.This research provides a comprehensive investigation of the characteristics of cerebrospinal fluid(CSF)flow and pressure in a hydrocephalic patient.The influence of hydrocephalic CSF,flowing rotationally with realistic dynamical characteristics on pulsatile boundaries of subarachnoid space,was demonstrated using a nonlinear controlling system of CSF.An analytical perturbation method of hydrocephalus has been developed to investigate the biomechanics of fluid flow rate and the ventricular enlargement.In this paper presents a detailed analysis of CSF flow and pressure dynamics in a hydrocephalic patient.It was elaborated with a nonlinear governing model of CSF to show the influence of hydrocephalic CSF,flowing rotationally with realistic dynamical behaviors on pulsatile boundaries of subarachnoid space.In accordance with the suggested model,the elasticity factor changes depending on how much a porous layer,in this case the brain parenchyma,is stretched.It was improved to include the relaxation of internal mechanical stresses for various perturbation orders,modelling the potential plasticity of brain tissue.The initial geometry that was utilised to create the framework of CSF with pathological disease hydrocephalus and indeed the output of simulations using this model were compared to the actual progression of ventricular dimensions and shapes in patients.According to this observation,the non-linear and elastic mechanical phenomena incorporated into the current model are probably true.Further modelling of ventricular dilation at a normal pressure may benefit from the existence of a valid model whose parameters approximate genuine mechanical characteristics of the cerebral cortex.

Study on leakage recharge mechanism of confined fresh water aquifer with semi-permeable membrane in Tianjin plain area

The Group Ⅱ fresh groundwater bearing aquifers in the eastern plain of Tianjin underwent long term exploitation. This study shows that the area with greater water-level declining is associated with more rapid stratigraphic compaction and consolidation. In the study area, the salty groundwater in the un-exploited overlying aquifers have the same dynamic characteristic of synchronization but different amplitude with the Group Ⅱ aquifers, showing that they have a close relationship. Cross-sectional study indicated that surface water, salty groundwater and underlying fresh groundwater belong to an integral water resources system. The compacted clay layers have the feature of semi-permeable membrane under alkaline condition. The infiltration of surface water is driven by the differences of osmotic pressure of salty water in each layer. When the water level difference between the Group Ⅱ aquifers and overlying salty aquifers is greater than osmotic water pressure difference, the salt water layer will desalinate downward and eventually, decreasing the water level of the upper aquifers, turning phreatic water amount supposed to evaporate to leakage recharge. Therefore, stopping mining groundwater in the Group Ⅱ aquifer will lead to other new environmental geology disaster.

A cold ^(87)Rb atomic beam

We demonstrate an experimental setup for the production of a beam source of cold 87Rb atoms. The atoms are extracted from a trapped cold atomic cloud in an unbalanced three-dimensional magneto-optical trap. Via a radiation pressure difference generated by a specially designed leak tunnel along one trapping laser beam, the atoms are pushed out continuously with low velocities and a high flux. The most-probable velocity in the beam is varied from 9 m/s to 19 m/s by varying the detuning of the trapping laser beams in the magneto-optical trap and the flux can be tuned up to 4× 10^9 s-1 by increasing the intensity of the trapping beams. We also present a simple model for describing the dependence of the beam performance on the magneto optical trap trapping laser intensity and the detuning.

A numerical investigation of gas flow behavior in two-layered coal seams considering interlayer interference and heterogeneity

Multiple-seam gas coproduction is a technology with potential to achieve economic targets.Physical experiments could replicate gas flow dynamics in two seams.In this study,numerical simulation was conducted based on physical experiments.Through calibration,the simulated results agreed with the experimental results.Three findings were obtained.First,the pressure distribution intrinsically depends on the depressurization effectiveness in each coal seam.The gas pressure difference and interval distance influence the pressure distribution by inhibiting depressurization in the top seams and bottom seams,respectively.Second,the production contribution shows a logarithmic relationship with the permeability ratio.The range of the production contribution difference grows from 11.24%to 99.99%when the permeability ratio increases 50 times.By comparison,reservoir pressure has a limited influence,with a maximum of 13.64%.Third,the interlayer interference of the top seams and bottom seams can be intensified by the reservoir pressure difference and the interval distance,respectively.The proposed model has been calibrated and verified and can be directly applied to engineering,serving as a reference for reservoir combination optimization.In summary,coal seams with a permeability ratio within 10,reservoir pressure difference within 1.50 MPa,and interval distances within 50 m are recommended to coproduce together.

Regulation of the intermittent release of giant unilamellar vesicles under osmotic pressure

Osmotic pressure can break the fluid balance between intracellular and extracellular solutions.In hypo-osmotic so-lution,water molecules,which transfer into the cell and burst,are driven by the concentration difference of solute across the semi-permeable membrane.The complicated dynamic processes of intermittent bursts have been previously observed.However,the underlying physical mechanism has yet to be thoroughly explored and analyzed.Here,the intermittent re-lease of inclusion in giant unilamellar vesicles was investigated quantitatively,applying the combination of experimental and theoretical methods in the hypo-osmotic medium.Experimentally,we adopted a highly sensitive electron multiplying charge-coupled device to acquire intermittent dynamic images.Notably,the component of the vesicle phospholipids af-fected the stretch velocity,and the prepared solution of vesicles adjusted the release time.Theoretically,we chose equations and numerical simulations to quantify the dynamic process in phases and explored the influences of physical parameters such as bilayer permeability and solution viscosity on the process.It was concluded that the time taken to achieve the balance of giant unilamellar vesicles was highly dependent on the molecular structure of the lipid.The pore lifetime was strongly related to the internal solution environment of giant unilamellar vesicles.The vesicles prepared in viscous solution were able to visualize long-lived pores.Furthermore,the line tension was measured quantitatively by the release velocity of inclusion,which was of the same order of magnitude as the theoretical simulation.In all,the experimental values well matched the theoretical values.Our investigation clarified the physical regulatory mechanism of intermittent pore forma-tion and inclusion release,which provides an important reference for the development of novel technologies such as gene therapy based on transmembrane transport as well as controlled drug delivery based on liposomes.

The effect of increased intra-abdominal pressure on orbital subarachnoid space width and intraocular pressure

In accordance with the trans-lamina cribrosa pressure difference theory, decreasing the trans-lamina cribrosa pressure difference can re- lieve glaucomatous optic neuropathy. Increased intracranial pressure can also reduce optic nerve damage in glaucoma patients, and a safe, effective and noninvasive way to achieve this is by increasing the intra-abdominal pressure. The purpose of this study was to observe the changes in orbital subarachnoid space width and intraocular pressure at elevated intra-abdominal pressure. An inflatable abdominal belt was tied to each of 15 healthy volunteers, aged 22-30 years （12 females and 3 males）, at the navel level, without applying pressure to the abdomen, before they laid in the magnetic resonance imaging machine. The baseline orbital subarachnoid space width around the optic nerve was measured by magnetic resonance imaging at 1, 3, 9, and 15 mm behind the globe. The abdominal belt was inflated to increase the pressure to 40 mmHg （1 mmHg = 0.133 kPa）, then the orbital subarachnoid space width was measured every 10 minutes for 2 hours. After removal of the pressure, the measurement was repeated 10 and 20 minutes later. In a separate trial, the intraocular pressure was measured for all the subjects at the same time points, before, during and after elevated intra-abdominal pressure. Results showed that the baseline mean orbital subarachnoid space width was 0.88 ＋ 0.1 mm （range： 0.77-1.05 mm）, 0.77 ＋ 0.11 mm （range： 0.60-0.94 mm）, 0.70 ＋ 0.08 mm （range： 0.62-0.80 ram）, and 0.68 _＋ 0.08 mm （range： 0.57-0.77 mm） at 1, 3, 9, and 15 mm behind the globe, respectively. During the elevated intra-abdominal pressure, the orbital subarachnoid space width increased from the baseline and dilation of the optic nerve sheath was significant at 1, 3 and 9 mm behind the globe. After decompression of the abdominal pressure, the orbital subarachnoid space width normalized and returned to the baseline value. There was no significant difference in the intraocular pressure before, during and after the intra-abdominal pressure elevation. These results verified that the increased intra-abdominal pressure widens the orbital subarachnoid space in this acute trial, but does not alter the intraocular pressure, indicating that intraocular pressure is not affected by rapid increased in- tra-abdominal pressure. This study was registered in the Chinese Clinical Trial Registry （registration number： ChiCTR-ONRC-14004947）.

Analysis of flow response to fluctuation of rotational speed in a radial impeller

By discretizing the convection terms with AUSM+-up scheme in the rotating coordinate system,a finite volume analysis code based on multi-block structured grids was developed independently so as to realize the numerical solving of internal flow fields of turbomachineries.Taking an unshrouded radial impeller with the working fluid of water vapour as the research object,the flow response to the fluctuation of rotational speed was calculated.By comparing the surface pressure profiles and velocity contours calculated by the code and commercial software respectively,the accuracy of flow solver was verified.The analysis of flow response data indicates that,as the working condition shifts closer towards the surge boundary,the response of flow parameters such as mass flow and aerodynamic torque will be more nonsynchronous with the fluctuation of rotational speed,and also the influence of density variation on mass flow variation will be smaller.Moreover,the transient variation region of working condition performance will deviate farther away from the steady performance curve as the working condition approaches the surge boundary.Compared to the working conditions with small mass flows,the distribution characteristics of pressure difference load on the blade surface vary little under large mass flow conditions.The reduction of fluctuation amplitude of rotational speed exerts no influence on abating the hysteresis of flow response.

Pulse cleaning flow models and numerical computation of candle ceramic filters

Analytical and numerical computed models are developed for reverse pulse cleaning system of candle ceramic filters. A standard turbulent model is demonstrated suitably to the designing computation of reverse pulse cleaning system from the experimental and one dimensional computational result. The computed results can be used to guide the designing of reverse pulse cleaning system, which is optimum Venturi geometry. From the computed results, the general conclusions and the designing methods are obtained.

Analogy Theory and Application of Pressure Difference of Wind Turbine Blade Profile

This paper aims to design an optimized blade for Horizontal Axis Wind Turbine(HWAT).Since airfoil is a basic component of blade design,an optimized airfoil(referred as SJX)was proposed based on the line theory through the weight analogy to pressure distribution of air flow.Its lift,drag,lift⁃to⁃drag ratio were compared with those NACA2409⁃34,NACA2410,and RK40 airfoils by using Profili software at fixed wind velocity and under different angles of attack.The NACA2409⁃34 airfoil was found to be greatly similar with the SJX airfoil.Based on the Wilson method,blades using SJX and NACA2490⁃34 airfoils were developed and different performance parameters such as velocity distribution,pressure distribution,and power were compared under variable wind velocities and different angles of attack ranging from-4°to 6°at different radius from the center of rotor using computational fluid dynamics(CFD)in ANSYS FLUENT.Results of the study suggested that the performance of the SJX based airfoil and blade was much more optimized.

Association between Systolic Blood Pressure Difference ≥10 mm Hg and Ankle-Brachial Index

Background: In new outpatients, blood pressure should be measured in both arms. A previous study reported that an inter-arm systolic blood pressure difference (ΔSBP) of ≥10 mm Hg is associated with an increased risk of mortality. Aim: The aim was to identify the associations with absolute values of ΔSBP (|ΔSBP|) ≥10 mm Hg. Subjects and Methods: This study included 2481 patients. Patients with a body mass index ≥25 kg/m2 were defined as obese. The group of A was defined as following: ankle-brachial index (ABI) was <0.9 or ≥1.3. ΔSBP was expressed as right arm BP minus left arm BP. |ΔSBP| ≥10 mm Hg were analyzed using multivariate logistic analysis. Results: |ΔSBP| ≥10 mm Hg was found in 6.0% of patients and |ΔSBP| < 5 mm Hg in 80.4%. In multivariate analysis, the odds ratios (ORs) of the associations with |ΔSBP| ≥10 mm Hg were significantly associated with abnormal ABI and obesity regardless of sex and age. Moreover, the OR of the combined effects of abnormal ABI and obesity was higher than that of abnormal ABI and obesity alone. Conclusion: |ΔSBP| ≥10 mm Hg was associated with abnormal ABI and obesity. In a primary care setting, blood pressure should be actively measured in both arms. This study suggests that the associations with |ΔSBP| ≥10 mm Hg may be a useful part of screening for abnormal ABI.

Research on Artificial Lateral Line Perception of Flow Field based on Pressure Difference Matrix

In nature,with the help of lateral lines,fish is capable of sensing the state of the flow field and recognizing the surrounding near-fleld hydrodynamic environment in the condition of weak light or even complete darkness.In order to study the application of lateral lines,an improved pressure distribution model was proposed in this paper,and the pressure distributions of the lateral line carrier under different working conditions were obtained using hydrodynamic simulations.Subsequently,a visualized pressure difference matrix was constructed to identify the flow fields under different working conditions.The role of the lateral lines was investigated from a visual image perspective.Instinct features of different flow velocities,flow angles and obstacle offset distances were mapped into the pressure difference matrix.Lastly,a four-layer Convolutional Neural Network(CNN)model was built as a recognition tool to evaluate the effectiveness of the pressure difference matrix method.The recognition results demonstrate that the CNN can identify the flow field state with 2 s earlier than the current time.Hence,the proposed method provides a new way to identify flow field information in engineering applications.

Finite element analysis of trans-lamina cribrosa pressure difference on optic nerve head biomechanics: the Beijing Intracranial and Intraocular Pressure Study

The present study aims to assess the potential difference of biomechanical response of the optic nerve head to the same level of trans-lamina cribrosa pressure difference(TLCPD) induced by a reduced cerebrospinal fluid pressure(CSFP) or an elevated intraocular pressure(IOP). A finite element model of optic nerve head tissue(pre-and post-laminar neural tissue, lamina cribrosa, sclera, and pia mater) was constructed. Computed stresses, deformations, and strains were compared at each TLCPD step caused by reduced CSFP or elevated IOP. The results showed that elevating TLCPD increased the strain in optic nerve head,with the largest strains occurring in the neural tissue around the sclera ring. Relative to a baseline TLCPD of 10 mmHg, at a same TLCPD of 18 mmHg, the pre-laminar neural tissue experienced 11.10% first principal strain by reduced CSFP and 13.66% by elevated IOP, respectively. The corresponding values for lamina cribrosa were 6.09% and 6.91%. In conclusion, TLCPD has a significant biomechanical impact on optic nerve head tissue and, more prominently, within the pre-laminar neural tissue and lamina cribrosa. Comparatively, reducing CSFP showed smaller strain than elevating IOP even at a same level of TLCPD on ONH tissue, indicating a different potential role of low CSFP in the pathogenesis of glaucoma.

A novel low pressure-difference fluctuation electro-hydraulic large flowrate control valve for fuel flowrate control of aeroengine afterburner system

To address the control accuracy of large fuel flowrate during pressure fluctuation,a novel electro-hydraulic fuel metering unit(FMU)is constructed for afterburner fuel system of military aeroengine.Different from the previous FMU,the proposed FMU can achieve the higher precision opening control by a new metering valve with double control chambers(MVDCC),and realize the lower pressure difference fluctuation regulating by a novel two-stage constant pressure difference compensated valve(CPDCV)with dynamic damping orifice and damping piston.The experimental and AMESim simulation results verify the validity and superiority of the novel FMU.Since the temperature-induced variation in fuel properties and device capabilities may degrade or even impair the properties of novel FMU,the discharge flowrate is analyzed by global sensitivity analysis to research the effect proportion of each factor,the temperature effect is explored to ensure the working reliability in long-span temperature variation.Finally,the optimization of structure parameters for novel CPDCV can further reduce pressure difference fluctuation during pressure regulation,and the overshoot,adjust time and the integral of time multiplied by absolute value of error(ITAE)can be reduced by 24%,30%and 26%,respectively.This paper provides a reference for improving the stability of large flowrate during pressure fluctuation.

Intracranial hypotension and co-existent normal-pressure glaucoma： the Beijing intracranial and intraocular pressure study

n contrast to the so-called intraocular pressure, which is .the transcomeal pressure difference, it is thetrans-lamina cribrosa pressure difference, which is of importance for physiology and pathophysiology of the optic nerve head. The trans-lamina cribrosa pressure difference is the difference between the pressure in the intraocular compartment （i.e., the so-called intraocular pressure） minus the retrobulbar pressure, which is formed by the orbital cerebrospinal fluid （CSF）I pressure and the retrobulbar optic nerve tissue pressure. This anatomical fact has been the basis for the speculation that some patients with so-called normal intraocular pressure glaucoma have an abnormally low orbital CSF pressure. Previous clinical studies have supported this hypothesis.2＇3 The purpose of this study is to report on a patient with low CSF pressure and co-existent open-angle glaucoma with normal intraocular pressure.