Emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate obtained by Corolase PP under high hydrostatic pressure

Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods.

Potential of high hydrostatic pressure in reducing the allergenicity of seafood

Seafood,as a primary high-quality protein source,plays an increasingly vital role in diets around the world,while seafood allergy is a worldwide health problem that affects the quality of life and may even threaten lives.High hydrostatic pressure(HHP),a novel non-thermal processing technology,shows the unique potential in alleviating seafood allergenicity.This comment provides a brief introduction of potential of high hydrostatic pressure in reducing the allergenicity of seafood.

Buckling of composite cylindrical shells with ovality and thickness variation subjected to hydrostatic pressure

The initial geometric imperfection is one of the primary factors affecting the buckling behaviors of composite cylindrical shells under hydrostatic pressure.In this study,ovality and thickness variations as two representative types of the geometric imperfections are considered.After measuring the geometric imperfections,a typical carbon fiber reinforced polymers(CFRP)cylindrical shell is tested to obtain the buckling pressure.The buckling behaviors of the shell sample are analyzed in combination with the strain responses.By using the nonlinear numerical analysis,the buckling shapes of the CFRP cylinder shells with different combinations of ovality and thickness variation are firstly discussed.The rules of influence of such imperfections on the buckling pressure are then obtained by nonlinear regression method.Finally,an empirical formula is proposed to predict the buckling pressure of the composite cylinder shells,and the calculated results from the formula are in good agreement with the numerical results.

The impact of high hydrostatic pressure treatment time on the structure,gelatinization and thermal properties and in vitro digestibility of oat starch

As a non-thermal processing technology,high hydrostatic pressure(HHP)can be used for starch modification without affecting the quality and flavour constituents.The effect of HHP on starch is closely related to the treatment time of HHP.In this paper,we investigated the impacts of HHP treatment time(0,5,10,15,20,25,30 min)on the microstructure,gelatinization and thermal properties as well as in vitro digestibility of oat starch by scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,13C NMR and differential scanning calorimeter.Results showed that 5-min HHP treatment led to deformation and decreases in short-range ordered and doublehelix structures of oat starch granules,and further extending the treatment time to 15 min or above caused the formation of a gelatinous connection zone,increase of particle size,disintegration of short-range ordered and double-helix structures,and crystal structure change from A type to V type,indicating gelatinization occurred.Longer treatment time also resulted in the reduction in both the viscosity and the stability of oat starch.These indicated that HHP treatment time greatly influenced the microstructure of oat starch,and the oat starch experienced crystalline destruction(5 min),crystalline disintegration(15 min)and gelatinization(>15 min)during HHP treatment.Results of in vitro digestibility showed that the rapidly digestible starch(RDS)content declined first after treatment for 5 to 10 min then rose with the time extending from 15 to 30 min,indicating that longer pressure treatment time was unfavourable to the health benefits of oat starch for humans with diabetes and cardiovascular disease.Therefore,the 500-MPa treatment time for oat starch is recommended not more than 15 min.This study provides theoretical guidance for the application of HHP technology in starch modification and development of health foods.

Dynamic ModeⅡfracture behavior of rocks under hydrostatic pressure using the short core in compression(SCC)method

The shear failure of rocks under both a static triaxial stress and a dynamic disturbance is common in deep underground engineering and it is therefore essential for the design of underground engineering to quantitively estimate the dynamic ModeⅡfracture toughness KⅡCof rocks under a triaxial stress state.However,the method for determining the dynamic KⅡCof rocks under a triaxial stress has not been developed yet.With an optimal sample preparation,the short core in compression(SCC)method was designed and verified in this study to measure the dynamic KⅡCof Fangshan marble(FM)subjected to different hydrostatic pressures through a triaxial dynamic testing system.The formula for calculating the dynamic KⅡCof the rock SCC specimen under hydrostatic pressures was obtained by using the finite element method in combination with secondary cracks.The experimental results indicate that the failure mode of the rock SCC specimen under a hydrostatic pressure is the shear fracture and the KⅡCof FM increases as the loading rate.In addition,at a given loading rate the dynamic rock KⅡCis barely affected by hydrostatic pressures.Another important observation is that the dynamic fracture energy of FM enhances with loading rates and hydrostatic pressures.

Distinct influence of trimethylamine N-oxide and high hydrostatic pressure on community structure and culturable deep-sea bacteria

Trimethylamine N-oxide(TMAO)is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains.To assess the impact of TMAO on marine microorganisms,especially those dwelling in the deep-sea environment,we analyzed the bacterial community structure of deep-sea sediments after incubated under different conditions.Enrichments at 50 MPa and 0.1 MPa revealed that TMAO imposed a greater influence on bacterial diversity and community composition at atmospheric pressure condition than that under high hydrostatic pressure(HHP).We found that pressure was the primary factor that determines the bacterial community.Meanwhile,in total,238 bacterial strains were isolated from the enrichments,including 112 strains a ffiliated to 16 genera of 4 phyla from the Yap Trench and 126 strains a ffiliated to 11 genera of 2 phyla from the Mariana Trench.Treatment of HHP reduced both abundance and diversity of isolates,while the presence of TMAO mainly af fected the diversity of isolates obtained.In addition,certain genera were isolated only when TMAO was supplemented.Taken together,we demonstrated that pressure primarily defines the bacterial community and culturable bacterial isolates.Furthermore,we showed for the first time that TMAO had distinct influences on bacterial community depending on the pressure condition.The results enriched the understanding of the significance of TMAO in bacterial adaptation to the deep-sea environment.

Restoration of Ultimate Strength of Dented Hemispheres Under External Hydrostatic Pressure

This study aimed to restore the ultimate strength of dented stainless-steel hemispheres with a radius of 90 mm and a thickness of 0.86 mm.All of the hemispheres were subjected to external hydrostatic pressure.Small stainless-steel stiffened caps were used to eliminate the effect of indention on the ultimate strength.These caps had a radius of 36 mm,a thickness of 0.76 mm,and a height of 10.44 mm.Six hemispherical samples,including two intact hemispheres,two dented hemispheres without stiffening,and two dented hemispheres with stiffening,were prepared.Each hemi-sphere was geometrically measured for shape and thickness,hydrostatically tested for destruction,and numerically evaluated for comparison.The experimental and numerical data agreed well with each other.As a result,a spherical cap can effectively restore the ultimate strength of dented hemispheres under external hydrostatic pressure.The proposed restoration approach can be used to strengthen underwater pressure hulls with large local geometric imperfections.

Extraction of β-Carotene,Vitamin C and Antioxidant Compounds from Physalis peruviana(Cape Gooseberry)Assisted by High Hydrostatic Pressure

High hydrostatic pressure assisted extraction (HHPE) has several advantages when compared to traditional extraction methods, which frequently cause degradation and loss of target components and might consume large volumes of environmentally unfriendly solvents. The aim of this study was to develop an assisted extraction method using high hydrostatic pressure (HHPE) and to evaluate both HHPE and conventional extraction methods for β-carotene, antioxidant compounds and vitamin C from cape gooseberry. β-carotene and compounds with antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical assay (DPPH*) or radical scavenging activity;ferric reducing antioxidant power assay (FRAP)) were extracted using HHPE for 5 min, 10 min and 15 min at 500 MPa, while vitamin C was extracted at 500 MPa for 30 s, 60 s and 90 s. Processing significantly affected (p ≤ 0.05) the β-carotene content of all samples, increasing retention by 8%, 14% and 15% at 500 MPa after 5 min, 10 min and 15 min of HPPE, respectively. The highest antioxidant content determined by DPPH* and FRAP assays was obtained in a sample treated at 500 MPa for 15 min, showing increases of 26% and 51%, respectively, compared with an untreated sample. The ascorbic acid content of fresh cape gooseberry was 26.31 mg·100 g-1. In fact, the ascorbic acid levels were significantly higher for all high-pressure-treated samples compared to this of conventionally extracted sample (p ≤ 0.05), exhibiting increases of 9%, 41% and 53% at 500 MPa after 30 s, 60 s and 90 s of HPPE, respectively. Thus, the application of HHPE produced higher β-carotene content, antioxidant compounds and vitamin C content and required less extraction time compared to other extraction methods. The pharmaceutical and food industries can benefit by using high pressure extraction technology.

A facile cell culture device for studying nuclear and mitochondrial response of endothelial cells to hydrostatic pressure

There is no clear consensus regarding how cells respond to hydrostatic pressure. This is largely attributable to the high heterogeneity among cell types and the diverse custom-made devices used in previous studies. The aim of this work was to develop a facile device that could mimic various pressure environments and then delineate the cellular response to pressure stimulus. The device described here achieved both stable and periodic pressurization without oxygen deprivation. The biological utility of the device was assessed using human umbilical vein endothelial cells. We found more stereoscopic nuclear morphology and re-distribution of lamin A/C under high hydrostatic pressure compared to control cells. Mass spectrometry-based proteomics analysis showed significant changes in mitochondria-related pathways. Western blot analysis confirmed that high hydrostatic pressure induced a tendency toward mitochondrial fusion. Increased mitochondrial activity was observed as well. In conclusion, this device can be readily applied in biological research and extend our understanding of cellular mechano-sensation and the associated changes in mitochondrial behaviors.

Corrosion form transition of mooring chain in simulated deep-sea environments:Remarkable roles of dissolved oxygen and hydrostatic pressure

The corrosion form and mechanical properties deterioration of mooring chain steel in simulated deep-sea environments were investigated.With the increase of ocean depth,not only the pressure increases,but also the dissolved oxygen content decreases.These two factors affect corrosion evolution of mooring chain steel in simulated deep-sea environments,which was studied for the first time.Compared with uniform corrosion of mooring chain steel in shallow sea with sufficient oxygen,low dissolved oxygen leads to the corrosion dominated by pitting with pit covers.Meanwhile,hydrostatic pressure distinctly accelerates pitting initiation and propagation.The higher the hydrostatic pressure is,the more serious the pitting is.For failure mechanism of unstressed mooring chain steel serving in simulated deep-sea environments,both absorbed hydrogen and corrosion morphology can degrade the ductility of mooring chain steel,in which the leading factor depends on the service time.The severe pitting is the main factor and causes remarkable ductility loss of the steel after long-term immersion.But hydrogen plays an important role on elongation loss in early stage.

Effects of magnetic field and hydrostatic pressure on the antiferromagnetic-ferromagnetic transition and magneto-functional properties in Hf_(1-x)Ta_(x)Fe_(2)alloys

In this study,the thermal expansion of Hf_(1-x)Ta_(x)Fe_(2)(x=0.10,0.13,0.15)compounds by adjusting the Ta concentration was successfully regulated.The magnetocaloric properties,hydrostatic pressure affecting the antiferromagnetic-ferromagnetic transition,and magnetostriction in the low magnetic field were studied.TheΔS_(M)values of 3.3 J·(kg-K)^(-1)and 3.6 J·(kg·K)^(-1)were obtained under magnetic fields of 10 kOe and 15 kOe in the Hf_(0.85)Ta_(0.15)Fe_(2),respectively.In the antiferromagnetic-ferromagnetic state transformation process under hydrostatic pressure up to 0.8 GPa,the state temperature does not decrease in a strictly linear manner.Outstanding magnetostrictive properties of 0.12%were obtained at a magnetic field of 10 kOe.This kind of alloy is supposed to be controlled under hydrostatic pressure to obtain good magnetic refrigeration performance and magnetostrictive properties.

Finite element analysis of effect of interfacial bubbles on performance of epoxy coatings under alternating hydrostatic pressure

The stresses around bubbles formed on a coating/substrate interface under hydrostatic pressure(HP)and alternating hydrostatic pressure(AHP)were calculated using the finite element method.The results reveal that HP promotes coating failure but does not mechanically destroy the interface,whereas AHP can provide tensile stress on bubbles formed at the interface and accelerate disbonding of the coating.Because of water resistance,a lag time exists for the coating that serves in an AHP environment.The coating can have a better protective performance if the lag time suits the AHP to minimize the impact of the AHP on the interface.

Effect of Hydrostatic Pressure on LPSO Kinking and Microstructure Evolution of Mg–11Gd–4Y–2Zn–0.5Zr Alloy

Two different kinds of hot compressions,namely normal-compression and can-compression,were performed on the Mg–11 Gd–4 Y–2 Zn–0.5 Zr alloy,featured with long period stacking ordered(LPSO)phase.The kinking behavior of LPSO phase and microstructure evolution was investigated to clarify the effect of levels of imposed hydrostatic pressure.The results suggest that the LPSO phases including both the intragranular 14 H-LPSO phase and intergranular 18 R-LPSO phase suffer severe kinking behavior under higher hydrostatic pressure induced by can-compression,which is firstly characterized with more kinking times and smaller relative kinking width.The main reason for such enhanced LPSO kinking during cancompression may be mainly ascribed to the higher dislocation density under a higher level of hydrostatic pressure.Meanwhile,a competitive relationship between the kink behaviors of intergranular 18 R-LPSO phase and intragranular 14 H-LPSO phase was observed.That is,the intergranular 18 R-LPSO phase only kinks obviously on the condition that the surrounded intragranular 14 H-LPSO phase scarcely kinks.In contrast to the distinctive kinking of LPSO phase,the dynamic recrystallization(DRX)mechanism shows less dependence on the hydrostatic pressure.Resultantly,similar DRX fractions and crystallographic texture were attained for two compression processes owing to the similar operation of deformation mode.

Single cell transcriptomic analysis identifies novel vascular smooth muscle subsets under high hydrostatic pressure

Although some co-risk factors and hemodynamic alterations are involved in hypertension progression,their direct biomechanical effects are unclear.Here,we constructed a high-hydrostatic-pressure cell-culture system to imitate constant hypertension and identified novel molecular classifications of human aortic smooth muscle cells(HASMCs)by single-cell transcriptome analysis.Under 100-mmHg(analogous to healthy human blood pressure)or 200-mmHg(analogous to hypertension)hydrostatic pressure for 48 h,HASMCs showed six distinct vascular SMC(VSMC)clusters according to differential gene expression and gene ontology enrichment analysis.Especially,two novel HASMC subsets were identified,named the inflammatory subset,with CXCL2,CXCL3 and CCL2 as markers,and the endothelial-function inhibitory subset,with AKR1C2,AKR1C3,SERPINF1 as markers.The inflammatory subset promoted CXCL2&3 and CCL2 chemokine expression and secretion,triggering monocyte migration;the endothelial-function inhibitory subset secreted SERPINF1 and accelerated prostaglandin F2αgeneration to inhibit angiogenesis.The expression of the two VSMC subsets was greatly increased in arterial media from patients with hypertension and experimental animal models of hypertension.Collectively,we identified high hydrostatic pressure directly driving VSMCs into two new subsets,promoting or exacerbating endothelial dysfunction,thereby contributing to the pathogenesis of cardiovascular diseases.

The role of hydrostatic pressure on the metal corrosion in simulated deep-sea environments—a review

This paper reviewed the corrosion behavior of metals in simulated deep-water environments and briefly discussed the effect of hydrostatic pressure on the different corrosion types for the active and the passive alloys.A consensus on the corrosion mechanism is that hydrostatic pressure accelerates the dissolution kinetics,changes the chemical compositions of the product layer or passive films,and promotes the adsorption of Cl^(-)on the metal surface.In addition,a newly-developed mechanism that hydrostatic pressure facilitates the dissolution process by thinning the electric double layer was reviewed,the synergistic effect of hydrostatic pressure and tensile stress on the stress corrosion cracking was discussed,and the modified coating with chemical bonding interface to prolong the service life in this environment was introduced.

Evaluation of coating resistivity for pigmented/unpigmented epoxy coatings under marine alternating hydrostatic pressure

To realize a rapid evaluation of coating degradation under alternating hydrostatic pressure(AHP),appropriate physical models of electrochemical impedance spectroscopy(EIS)data fitting were respectively developed for epoxy coatings with and without pigments,based on their different water absorption behaviours.Power-law model was selected to evaluate the anti-permeability of epoxy varnish(EV)coating,which tends to form through pores in the coating structure.On the other hand,two-layer model based on Young theory was developed to evaluate the anti-permeability of pigmented epoxy coating.Consequently,the resistivity profile with coating thickness was calculated as a critical parameter to describe the anti-permeability of coating at different immersion time.The interpretation of water diffusion dynamics based on different coating structures was also given,which is responsible for the choice of distribution models.

Effects of hydrostatic pressure and temperature on the nonlinear optical properties of semiparabolic plus semi-inverse squared quantum wells

In this study,the effects of hydrostatic pressure and temperature on nonlinear optical rectification(OR),second-harmonic generation(SHG),third-harmonic generation(THG)and the linear,nonlinear,and total optical absorption coefficients(OACs)of a semiparabolic plus semi-inverse squared quantum well(QW)are theoretically investigated.The results show that hydrostatic pressure and temperature have significant effects on the optical properties of semiparabolic plus semi-inverse squared QWs,and that the energy levels and magnitudes of the resonant peaks of OR,SHG,THG,and the total OACs vary according to the shape of the limiting potential,the hydrostatic pressure,and the temperature.It is easily seen that the peak positions of the resonant peaks of OR,SHG,THG,and the total OACs in the semiparabolic plus semi-inverse squared QW show a red shift with increasing hydrostatic pressure,but a blue shift with increasing temperature.Therefore,the magnitude and position of the resonant peaks of OR,SHG,THG,and the total OACs can be adjusted by changing the hydrostatic pressure and the temperature,which promise a new degree of freedom in the tunability of various electro-optical devices.

Optical properties of Al_(x)Ga_(1-x)As/GaAs Woods-Saxon quantum well in the presence of hydrostatic pressure and applied electric field

The third harmonic generation(THG),linear and nonlinear optical absorption coefficients(OACs),and refractive index changes(RICs)are investigated in a Woods-Saxon quantum well(QW)modulated by the hydrostatic pressure and applied electric field.The effect of non-uniform aluminum doping(position-dependent effective mass(PDEM))on the mass of the system is discussed,and further to explore the influence of PDEM on the nonlinear THG,OACs,and RICs of the Woods-Saxon QW.These nonlinear optical properties above are obtained using the compact-density matrix formalism.The electron states in a Woods-Saxon QW under the constant effective mass(CEM)and PDEM are calculated by solving the Schr?dinger equation via the finite difference technique.The contributions from competing effects of the hydrostatic pressure and applied electric field to the nonlinear optical properties with CEM and PDEM are reported,as well as the comparison with each other.The observations reveal that the regulation of external fields and the influence of PDEM play an important role in the photoelectric properties of QW.

Large enhancement of magnetocaloric effect induced by dual regulation effects of hydrostatic pressure in Mn_(0.94)Fe_(0.06)NiGe compound

MM'X(M,M'=transition metals,X=carbon or boron group elements)compounds could exhibit large magnetocaloric effect due to the magnetostructural transition,and the composition regulation has been widely studied to realize the magnetostructural transition.Moreover,the magnetostructural transition is also sensitive to the pressure.Herein,the effect of hydrostatic pressure on magnetostructural transformation and magnetocaloric effect has been investigated in Mn_(0.94)Fe_(0.06)NiGe compound.Dual regulation effect of lowering structural transition temperature and strengthening ferromagnetic(FM)state of martensite is realized by applying hydrostatic pressure,which would greatly improve the magnetocaloric effect of Mn_(0.94)Fe_(0.06)NiGe compound.Moreover,the first-principles calculations have also been performed to discuss the origin of the regulation effect under hydrostatic pressure,and it indicates that the hydrostatic pressure can stabilize the hexagonal structure and decrease the structural transition temperature.The maximum isothermal entropy change increases by 109%from 4.3 J/(kg K)under 0 GPa to 9.0 J/(kg K)under 0.402 GPa for a magnetic field change of 0-3 T.This work proves that the hydrostatic pressure is an effective method to regulate the magnetostructural transition and enhance magnetocaloric effect in MM'X compounds.

Influence of elastic foundations and carbon nanotube reinforcement on the hydrostatic buckling pressure of truncated conical shells

In this study,the effects of elastic foundations(EFs)and carbon nanotube(CNT)reinforcement on the hydrostatic buckling pressure(HBP)of truncated conical shells(TCSs)are investigated.The first order shear deformation theory(FOSDT)is generalized to the buckling problem of TCSs reinforced with CNTs resting on the EFs for the first time.The material properties of composite TCSs reinforced with CNTs are graded linearly according to the thickness coordinate.The Winkler elastic foundation(W-EF)and Pasternak elastic foundation(P-EF)are considered as the EF.The basic relations and equations of TCSs reinforced with CNTs on the EFs are obtained in the framework of the FOSDT and solved using the Galerkin method.One of the innovations in this study is to obtain a closed-form solution for the HBP of TCSs reinforced with CNTs on the EFs.Finally,the effects of the EFs and various types CNT reinforcements on the HBP are investigated simultaneously.The obtained results are compared with the results in the literature,and the accuracy of results is confirmed.