47,462 results match your criteria pressure carbon

Performance characteristics of high-frequency percussive ventilation under hyperbaric conditions.

Undersea Hyperb Med 2021 Second Quarter;48(2):157-168

Hyperbaric Medicine and Chronic Wound Clinic, Legacy Emanuel Medical Center, Portland, Oregon U.S.

Introduction: Safe administration of critical care hyperbaric medicine requires specialized equipment and advanced training. Equipment must be tested in order to evaluate function in the hyperbaric environment. High-frequency percussive ventilation (HFPV) has been used in intensive care settings effectively, but it has never been tested in a hyperbaric chamber. Read More

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Shifting access to pools of shoot water sustains gas exchange and increases stem hydraulic safety during seasonal atmospheric drought.

Plant Cell Environ 2021 May 11. Epub 2021 May 11.

Plant Science Division, Research School of Biology, Australian National University, Acton, Australia.

Understanding how plants acclimate to drought is crucial for predicting future vulnerability, yet seasonal acclimation of traits that improve drought tolerance in trees remains poorly resolved. We hypothesized that dry season acclimation of leaf and stem traits influencing shoot water storage and hydraulic capacitance would mitigate the drought-associated risks of reduced gas exchange and hydraulic failure in the mangrove Sonneratia alba. By late dry season, availability of stored water had shifted within leaves and between leaves and stems. Read More

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The Study of the Solid Polymer Electrolyte Oxygen Concentrator with Nanostructural Catalysts Based on Hydrophobized Support.

Nanotechnol Russ 2020 5;15(11):785-792. Epub 2021 May 5.

National Research Center "Kurchatov Institute", 123182 Moscow, Russia.

The efficient production of gaseous oxygen used in many branches of industry to provide human life in anaerobic environments and in medicine (e.g., in the case of acute respiratory failure as one of COVID-19 complications) is challenging nowadays. Read More

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Controlling factors of seasonal and spatial variation of riverine CO partial pressure and its implication for riverine carbon flux.

Sci Total Environ 2021 Apr 30;786:147332. Epub 2021 Apr 30.

Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China. Electronic address:

Global carbon cycle is closely related to the earth's energy budget, because CO plays an active role in the global climate change. The higher CO partial pressure (pCO) in inland water in comparison with atmosphere, causing a CO evasion from water to the air. However, the relationship between CO evasion, riverine carbon export, and hydrochemistry in watershed has remained largely unknown. Read More

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Interannual variability in net ecosystem carbon production in a rain-fed maize ecosystem and its climatic and biotic controls during 2005-2018.

PLoS One 2021 10;16(5):e0237684. Epub 2021 May 10.

Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.

Interannual variability (IAV) in net ecosystem carbon production (NEP) plays an important role in the processes of the carbon cycle, but the long-term trends in NEP and the climatic and biotic control of IAV in NEP still remain unclear in agroecosystems. We investigated interannual variability in NEP, expressed as annual values and anomalies, and its climatic and biotic controls using an eddy-covariance dataset for 2005-2018 for rain-fed spring maize in northeastern China. Average annual NEP was 270±31 g C m-2yr -1, with no significant changes over time. Read More

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Combined Density Functional Theory and Microkinetics Study to Predict Optimum Operating Conditions of Si(100) Surface Carbonization by Acetylene for High Power Devices.

J Phys Chem Lett 2021 May 10:4558-4568. Epub 2021 May 10.

Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.

The Si(100) surface carbonization mechanisms by acetylene are explored using density functional theory calculations combined with microkinetic simulations. The most stable acetylene adsorption geometries and their subsequent decomposition mechanisms to form a carbon dimer on the Si surface are investigated. Microkinetics simulations are further used to examine the optimal reaction conditions for obtaining a single-crystalline silicon carbide (SiC). Read More

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Acetate intercalated Mg-Al layered double hydroxides (LDHs) through modified amide hydrolysis: a new route to synthesize novel mixed metal oxides (MMOs) for CO capture.

Dalton Trans 2021 May 10. Epub 2021 May 10.

Research Centre for Carbon Solutions (RCCS), School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.

Layered double hydroxide (LDH) based mixed metal oxides (MMOs) are promising high temperature CO2 capture sorbents. In order to improve their CO2 capture capacity, it is crucial to bring in changes to their physicochemical properties such as morphology, particle size, surface area and activity by tuning the synthesis method. Here we report a modified amide hydrolysis method to synthesize LDHs with a mixed morphology and better CO2 capture properties. Read More

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Rapid Improvement of Severe Pulmonary Hypertension Due to Scoliosis-related Restrictive Ventilatory Disorder.

Intern Med 2021 May 7. Epub 2021 May 7.

Department of Respiratory Medicine, Tenri Hospital, Japan.

Few reports have highlighted the serial changes in pulmonary hypertension during respiratory management. An 18-year-old girl with severe scoliosis was referred to our hospital for worsening dyspnea on exertion. Based on chest X-ray and transthoracic echocardiography findings showing a tricuspid regurgitation pressure gradient (TRPG) of 64 mmHg, the patient was diagnosed with severe alveolar hypoventilation due to thoracic deformity and severe pulmonary hypertension. Read More

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Risk predictive role of hypernatremia for occurrence of sepsis-induced acute kidney injury.

Ann Palliat Med 2021 Apr;10(4):4705-4715

Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing, China.

Background: Septic acute kidney injury (AKI), identified when sepsis and AKI present concurrently, is a syndrome of acute function impairment and organ damage, which accounts for ~50% AKI in the intensive care unit (ICU).

Methods: This study retrospectively reviewed 591 patients who were diagnosed with sepsis and admitted to the ICU of Beijing Friendship Hospital from January 2009 to December 2014. According to the concentration of serum sodium, the 591 patients were further divided into 3 groups: normal group, hyponatremia group, and hypernatremia group. Read More

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Selective pressure of biphenyl/polychlorinated biphenyls on the formation of aerobic bacterial associations and their biodegradative potential.

Folia Microbiol (Praha) 2021 May 8. Epub 2021 May 8.

Laboratory of Molecular Microbiology and Biotechnology, Institute of Ecology and Genetics of Microorganism UB RAS, 13 Golev st, Perm, 614081, Russia.

Unique bacterial associations were formed in the polluted soils from territory of the industrial factories Open Joint Stock Company "The Middle Volga Chemical Plant," Chapaevsk, Russia and Open Joint Stock Company "Lubricant Producing Plant," Perm, Russia. This study evaluates the influence of the biphenyl/polychlorinated biphenyls (PCB) on the formation of aerobic bacterial associations and their biodegradative potential. Enrichment cultivation of the soil samples from the territories of these industrial factories with PCB (commercial mixture Sovol) was lead for forming aerobic bacterial enrichment cultures showing a unique composition. Read More

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Assessment of Cerebral Blood Oxygenation by Near-Infrared Spectroscopy before and after Resuscitation in a Rat Asphyxia Cardiac Arrest Model.

Adv Exp Med Biol 2021 ;1269:311-315

Feinstein Institute for Medical Research, Northwell Health System, Manhasset, NY, USA.

Clinical investigators have focused on the real-time evaluation of cerebral blood oxygenation (CBO) by near-infrared spectroscopy (NIRS) during cardiopulmonary resuscitation (CPR). A previous study showed that an abrupt increase of oxy-hemoglobin (Hb) level and tissue oxygenation index (TOI) was associated with the timing of return of spontaneous circulation (ROSC). However, it is not clear how TOI alters before and after CPR including a period of cardiac arrest (CA). Read More

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Relationship Between Decrease of Oxygenation During Incremental Exercise and Partial Pressure End-Tidal Carbon Dioxide: Near-Infrared Spectroscopy Vector Analysis.

Adv Exp Med Biol 2021 ;1269:119-124

Graduate School of Health and Welfare, Niigata University of Health and Welfare, Niigata, Japan.

A previous study considered that a decrease in cerebral oxyhemoglobin (OHb) immediately before maximal exercise during incremental exercise is related to cerebral blood flow (CBF) and partial pressure end-tidal carbon dioxide (PCO). This study aimed to investigate the relationship between OHb, PCO, and the estimated value of cerebral blood volume (CBV) with cerebral oxygen exchange (COE) by using vector analysis. Twenty-four healthy young men participated in this study. Read More

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Exceptional Cocatalyst-Free Photo-Enhanced Piezocatalytic Hydrogen Evolution of Carbon Nitride Nanosheets from Strong In-Plane Polarization.

Adv Mater 2021 May 8:e2101751. Epub 2021 May 8.

Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China.

Utilizing mechanical energy to produce hydrogen is emerging as a promising way to generate renewable energy, but is challenged by low efficiency and scanty cognition. In this work, graphitic carbon nitride (g-C N ) with an atomically thin sheet-like structure is applied for prominent piezocatalytic and photo-enhanced piezocatalytic H production. It is revealed that the anomalous piezoelectricity in g-C N originates from the strong in-plane polarization along the a-axis, contributed by the superimposed polar tri-s-triazine units and flexoelectric effect derived from the structured triangular cavities, which provides powerful electrochemical driving force for the water reduction reaction. Read More

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Impact of wearing a surgical and cloth mask during cycle exercise.

Appl Physiol Nutr Metab 2021 May 7. Epub 2021 May 7.

University of Waterloo, 8430, Department of Kinesiology, BMH 1110, 200 University Avenue West, Waterloo, Ontario, Canada, N2L 3G1;

We sought to determine the impact of wearing cloth or surgical masks on the cardiopulmonary responses to moderate-intensity exercise. Twelve subjects (n=5 females) completed three, 8-min cycling trials while breathing through a: non-rebreathing valve (laboratory control), cloth, or surgical mask. Heart rate (HR), oxyhemoglobin saturation (SpO2), breathing frequency (Fb), mouth pressure, partial pressure of end-tidal carbon dioxide (PetCO2) and oxygen (PetO2), dyspnea, were measured throughout exercise. Read More

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The Structure of the Active Pd State During Catalytic Carbon Monoxide Oxidization.

J Phys Chem Lett 2021 May 6:4461-4465. Epub 2021 May 6.

Department of Physics, Stockholm University, 10691 Stockholm, Sweden.

Using grazing incidence X-rays and X-ray photoelectron spectroscopy during the mass transfer limited catalytic oxidation of CO, the long-range surface structure of Pd(100) was investigated. Under the reaction conditions of 50:4 O to CO, 300 mbar pressure, and temperatures between 200 and 450 °C, the surface structure resulting from oxidation and the subsequent oxide reduction was elucidated. The reduction cycle was halted, and while under reaction conditions, angle-dependent X-ray photoelectron spectroscopy close to the critical angle of Pd and modeling of the data was performed. Read More

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Dynamic cerebral autoregulation and cerebrovascular carbon dioxide reactivity in middle and posterior cerebral arteries in young endurance-trained women.

J Appl Physiol (1985) 2021 May 6. Epub 2021 May 6.

Université Lavalgrid.23856.3a.

The integrated responses regulating cerebral blood flow are understudied in women, particularly in relation to potential regional differences. In this study, we compared dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity to carbon dioxide (CVR) in the middle (MCA) and posterior cerebral arteries (PCA) in 11 young endurance-trainedwomen (age: 25 ± 4 y; maximal oxygen uptake: 48.1 ± 4. Read More

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Temporal inversion of the acid-base equilibrium in newborns: an observational study.

PeerJ 2021 14;9:e11240. Epub 2021 Apr 14.

Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.

Background: A considerable fraction of newborn infants experience hypoxia-ischaemia and metabolic acidosis at birth. However, little is known regarding the biological response of newborn infants to the pH drift from the physiological equilibrium. The aim of this study was to investigate the relationship between the pH drift at birth and postnatal acid-base regulation in newborn infants. Read More

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The influence of medium composition on the microbial secretory production of hydroxyalkanoate oligomers.

J Gen Appl Microbiol 2021 May 1. Epub 2021 May 1.

Department of Materials Science and Engineering, Tokyo Institute of Technology.

With the aid of a chain transfer (CT) reaction, hydroxyalkanoate (HA) oligomers can be secreted by recombinant Escherichia coli carrying the gene encoding a lactate-polymerizing enzyme (PhaC1STQK) using Luria-Bertani (LB) medium supplemented with a carbon source and CT agent. In this study, HA oligomers were produced through microbial secretion using a mineral-based medium instead of LB medium, and the impact of medium composition on HA oligomer secretion was investigated. The focused targets were medium composition and NaCl concentration related to osmotic conditions. Read More

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A systematic review of the incidence, risk factors and prognosis of acute exacerbation of systemic autoimmune disease-associated interstitial lung disease.

BMC Pulm Med 2021 May 5;21(1):150. Epub 2021 May 5.

Department of Intensive Care Medicine, Northern Hospital, Melbourne, Australia.

Introduction: Acute exacerbation (AE) is a devastating phenomenon and reported to be complicated with systemic autoimmune disease-associated interstitial lung disease (ILD). The aim of this study was to investigate the incidence and prognosis of AE of systemic autoimmune disease-ILD and clarify relevant clinical information predictive of these outcomes.

Method: This study was designed as a systematic review and meta-analysis. Read More

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Expanding carbon capture capacity: uncovering additional CO adsorption sites in imine-linked porous organic cages.

Phys Chem Chem Phys 2021 May;23(17):10311-10320

Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z3, Canada.

With an increasing need to develop carbon capture technologies, research regarding the use of cage-based porous materials has garnered great interest. Typically, the study of gas adsorption in porous organic cages (POCs) has focused on the gas uptake inside the cage cavity. By using molecular dynamics simulation, this study reveals the presence of eight sites outside the cavity of a 15-crown-5 ether-substituted imine-linked POC which could enhance carbon dioxide adsorption capacity. Read More

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Evaluation of analgesic interaction between morphine, maropitant and dexmedetomidine in dogs undergoing ovariohysterectomy.

N Z Vet J 2021 May 5:1-27. Epub 2021 May 5.

School of Veterinary Science, Massey University, Palmerston North, New Zealand.

Aims: To compare the analgesic effect of morphine combined with maropitant and/or dexmedetomidine to morphine alone given at a higher dose, and to evaluate the pharmacokinetics of the drug combinations, in dogs undergoing ovariohysterectomy (OHE).

Methods: Forty client owned-dogs were randomised into four treatment groups (n=10 per group) each to receive a different analgesic protocol. After premedication with I/M acepromazine anaesthesia was induced with propofol to effect and maintained with isoflurane in 100% oxygen delivered via a circle system. Read More

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Reactive capture using metal looping: the effect of oxygen.

Faraday Discuss 2021 May 4. Epub 2021 May 4.

UK Centre for Carbon Dioxide Utilization, Department of Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Sheffield, UK.

In the effort to create a sustainable future economy, the ability to directly convert dilute gas-phase CO2 in waste gas streams into useful products would be a valuable tool, which may be achievable using Grignard reagents as both the capture and the conversion materials. The magnesium salt by-product can be recovered, and metallic magnesium regenerated through conventional high-efficiency electrolysis. This stoichiometric approach is known as metal looping, where the magnesium acts as the energy vector for the capture and conversion, allowing both to occur at room temperature and atmospheric pressure. Read More

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Plasma tailored reactive nitrogen species in MOF derived carbon materials for hybrid sodium-air batteries.

Dalton Trans 2021 May 4. Epub 2021 May 4.

Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China and State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China.

The rational design of efficient and durable electrocatalysts to accelerate sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics is highly desirable for enhancing the efficiency of fuel cells and metal-air batteries. Here, we demonstrated a low-temperature plasma strategy at atmospheric pressure for enhancing the catalytic activity of metal-organic framework derived N-doped carbon nanotubes (MOF-NCNTs) by changing the relative contents of Co-Nx sites, Co-Co bonds and pyridinic-N. The increase of pyridinic-N/pyrrolic-N ratio improves the ORR performance, while unsaturated Co-Nx sites and strong Co-Co bonds promote the OER performance. Read More

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Induced defense and its cost in two bryophyte species.

Am J Bot 2021 May 4. Epub 2021 May 4.

Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Renmin 5268, Changchun, 130024, China.

Premise: Current knowledge about defense strategies in plants under herbivore pressure is predominantly based on vascular plants. Bryophytes are rarely consumed by herbivores since they have ample secondary metabolites. However, it is unknown whether bryophytes have induced defenses against herbivory and whether there is a trade-off between growth and defense in bryophytes. Read More

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Experimental study on the effects of blending PODE on performance, combustion and emission characteristics of heavy-duty diesel engines meeting China VI emission standard.

Sci Rep 2021 May 4;11(1):9514. Epub 2021 May 4.

Air and Missile Defense College, Air Force Engineering University, Xi'an, 710051, People's Republic of China.

To study the influence of diesel fuel blended with polyoxymethylene dimethyl ethers (PODE), a new alternative fuel with a high oxygen content and large cetane number, on the combustion characteristics, fuel economies, and emission characteristics of heavy-duty diesel engines that meet China VI emission standards, relevant tests were conducted on a supercharged intercooled high-pressure common-rail diesel engine. The PODE were blended with diesel fuel at three different ratios (volume fractions of 10%, 20%, and 30%). The test results showed that the PODE could optimize the combustion process of diesel engines that met the China VI emission standards, effectively improve the thermal efficiencies of diesel engines, and reduce the emissions of hydrocarbon (HC), carbon monoxide (CO), and soot. Read More

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One-pot green synthesis of I@CNDs-FeO hybrid nanoparticles from kelp for multi-modal imaging in vivo.

Mater Sci Eng C Mater Biol Appl 2021 May 20;124:112037. Epub 2021 Mar 20.

Institute of Chemicobiology and Functional Materials, School of Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Street, Nanjing, Jiangsu Province, China.

Multi-modal imaging technologies are playing an increasingly important role in biomedical research. However, there remains a demanding challenge to develop biocompatible contrast agents via a simple, green synthetic route for multi-modal imaging. Here we report the synthesis and applications of a new contrast agent for triple-modal imaging, that is, iodine-containing N-doping carbon nano-dots hybridized with FeO nanoparticles (I@CNDs-FeO). Read More

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Development of Highly Efficient, Glassy Carbon Foam Supported, Palladium Catalysts for Hydrogenation of Nitrobenzene.

Nanomaterials (Basel) 2021 Apr 29;11(5). Epub 2021 Apr 29.

Institute of Chemistry, University of Miskolc, H-3515 Miskolc-Egyetemváros, Hungary.

Glassy carbon foam (GCF) catalyst supports were synthesized from waste polyurethane elastomers by impregnating them in sucrose solution followed by pyrolysis and activation (AC) using N and CO gas. The palladium nanoparticles were formed from Pd(NO). The formed palladium nanoparticles are highly dispersive because the mean diameters are 8. Read More

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Transition Metal Salts of Carboxylated Multiwalled Carbon Nanotubes in Combination with -hydroxyphthalimide as Catalytic Systems for Hydrocarbon Oxidation.

Materials (Basel) 2021 Apr 29;14(9). Epub 2021 Apr 29.

Department of Organic Chemical Technology and Petrochemistry, Silesian University of Technology, B. Krzywoustego 4, 44-100 Gliwice, Poland.

In this study, the transition metal (Co (II), Cu (II), and Mn (II)) salts of carboxylated carbon nanotubes were synthesized and characterized (the determined metal contents were in the range of 0.89-1.16%). Read More

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A Direct-Writing Approach for Fabrication of CNT/Paper-Based Piezoresistive Pressure Sensors for Airflow Sensing.

Micromachines (Basel) 2021 Apr 30;12(5). Epub 2021 Apr 30.

State Key Lab of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.

Airflow sensor is a crucial component for monitoring environmental airflow conditions in many engineering fields, especially in the field of aerospace engineering. However, conventional airflow sensors have been suffering from issues such as complexity and bulk in structures, high cost in fabrication and maintenance, and low stability and durability. In this work, we developed a facile direct-writing method for fabricating a low-cost piezoresistive element aiming at high-performance airflow sensing, in which a commercial pen was utilized to drop solutions of single-walled carbon nanotubes onto tissue paper to form a piezoresistive sensing element. Read More

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How adding a single methylene to dihydrofolate reductase can change its conformational dynamics.

J Chem Phys 2021 Apr;154(16):165103

Department of Chemistry, Georgetown University, Washington, District of Columbia 20057, USA.

Studies of the effects of pressure on proteins from piezophilic (pressure-loving) microbes compared with homologous proteins from mesophilic microbes have been relatively rare. Interestingly, such studies of dihydrofolate reductase show that a single-site mutation from an aspartic acid to a glutamic acid can reverse the pressure-dependent monotonic decrease in activity to that in a monotonic pressure-dependent activation. This residue is near the active site but is not thought to directly participate in the catalytic mechanism. Read More

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