All metabolite reference standards underwent a two-step derivatization procedure. Therefore 1 mg of each standard was dissolved in a solution of 1 ml methanol:water:isopropanol (2.5:1:1 v/v). Then 10 μl of each standard solution were taken out and evaporated to dryness. First, methoximation was performed to inhibit the ring formation of reducing sugars, protecting also all other aldehydes and ketones. A solution of 40 mg/ml O-methylhydroxylamine hydrochloride, (CAS: [593-56-6]; Formula CH5NO.HCl; Sigma-Aldrich No. 226904 (98%)) in pyridine (99.99%) was prepared. The dried standards and 10 μl of the O-methylhydroxylamine reagent solution were mixed for 30 s in a vortex mixer and subsequently shaken for 90 minutes at 30°C. Afterwards, 90μl of N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) with 1% trimethylchlorosilane (TMCS) (1 ml bottles, Pierce, Rockford IL) was added and shaken at 37°C for 30 min for trimethylsilylation of acidic protons to increase volatility of metabolites. A mixture of internal retention index (RI) markers was prepared using fatty acid methyl esters (FAME markers) of C8, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28 and C30 linear chain length, dissolved in chloroform at a concentration of 0.8 mg/ml (C8-C16) and 0.4 mg/ml (C18-C30). 2 μl of this RI mixture were added to the reagent solutions, transferred to 2 mL glass crimp amber autosampler vials. Data acquisition parameters are given in table 1 . Subsequent to data processing using the instrument manufacturer’s software programs, spectra and retention indices were manually curated into the new Leco FiehnLib (359-008-100) or automatically transferred by Agilent to the new Agilent FiehnLib (G1676AA).
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Protons
Protons
Protons are fundamental subatomic particles that make up the nuclei of atoms.
They have a positive electric charge and a mass approximately 1,836 times greater than that of an electron.
Protons play a crucial role in the structure and stability of atomic nuclei, and their interactions with other particles are essential to many physical and chemical processes.
Protons can be accelerated to high energies and used in a variety of scientific applications, including particle physics research, medical imaging, and cancer therapy.
Understanding the properties and behavior of protons is a key area of study in fields such as nuclear physics, astrophysics, and quantum mechanics.
They have a positive electric charge and a mass approximately 1,836 times greater than that of an electron.
Protons play a crucial role in the structure and stability of atomic nuclei, and their interactions with other particles are essential to many physical and chemical processes.
Protons can be accelerated to high energies and used in a variety of scientific applications, including particle physics research, medical imaging, and cancer therapy.
Understanding the properties and behavior of protons is a key area of study in fields such as nuclear physics, astrophysics, and quantum mechanics.
Most cited protocols related to «Protons»
Acids
Aldehydes
Amber
Cardiac Arrest
Chloroform
Esters
Fatty Acids
Isopropyl Alcohol
Ketones
Methanol
methoxyamine
Protons
pyridine
Retention (Psychology)
Sugars
trimethylchlorosilane
Volatility
Biological Evolution
HMQC
Nitrogen
Proteins
Protons
Pulse Rate
Radionuclide Imaging
Reconstructive Surgical Procedures
VP-16
The electrostatic calculations outlined above provide (free) energies of each of the 2N protonation microstates (10 (link)) in the system, where N is the number of ionizable sites. To make the subsequent calculation of the partition functions (and pK1/2) manageable, a fast variant of a clustering approach is used (34 (link)). The approach subdivides the interacting sites into independent clusters based upon the strength of electrostatic site–site interactions between them. All electrostatic interactions for each ionizable site are sorted from highest to lowest; the top Cmax sites are then selected to contribute to the calculation, and all others are ignored. The partition function for the site is then factored into computationally manageable components of maximum size Cmax. Here, Cmax = 17 is used: in tests on 600 representative proteins (35 (link)), we found (J. Myers, G. Grothaus and A. Onufriev, manuscript submitted) that Cmax = 17 resulted in average errors of 0.2 pK units, compared with a standard treatment based upon a Monte Carlo approach (16 (link)).
The probability of protonation is computed for every site over a range of pH values equally spaced by 0.1 pH units apart. Individual curves can be displayed for user-selected residues, and the total protonation curve is generated, showing the computed isoelectric point of the molecule. A diagram showing the 10 lowest protonation states and their relative free energies is also generated. These diagrams were found useful (10 (link)) for analysis of proton transfer events in biomolecular systems.
The probability of protonation is computed for every site over a range of pH values equally spaced by 0.1 pH units apart. Individual curves can be displayed for user-selected residues, and the total protonation curve is generated, showing the computed isoelectric point of the molecule. A diagram showing the 10 lowest protonation states and their relative free energies is also generated. These diagrams were found useful (10 (link)) for analysis of proton transfer events in biomolecular systems.
Electrostatics
Proteins
Protons
The FreeSurfer (version 5.1.0) pipeline was used to generate cortical and subcortical volumetric measures (Dale et al., 1999 (link); Fischl et al., 1999 (link)). Estimated Total Intracranial Volume (eTIV) generated by FreeSurfer was used as an estimate for ICV in this study. The eTIV measure from FreeSurfer is in good agreement with ICV reference segmentation acquired from proton density weighted images) (Nordenskjöld et al., 2013 (link)) and has previously been used in several studies for normalization (Westman et al., 2011 (link), 2012 (link), 2013 (link)). The pipeline generated 68 cortical volumes (34 from each hemisphere) and 46 subcortical volumes. Volumes of white matter hypointensities, optic chiasm, right and left vessel, and left and right choroid plexus were excluded from further analysis. Cortical and subcortical volumetric measures from the right and left side were averaged (Walhovd et al., 2011 (link); Westman et al., 2013 (link)). In total 34 regional cortical volumes and 17 subcortical volumes were used for final analysis in the study. Image processing steps were visually inspected (skull-stripping errors and gray/white matter boundary) to ensure they had been carried out correctly.
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Blood Vessel
Cortex, Cerebral
Cranium
Optic Chiasms
Plexus, Chorioid
Protons
White Matter
The CI of the eight celluloses was measured by two different techniques: XRD and solid-state 13C NMR. XRD was performed on a four-circle goniometer (XDS-2000 Polycrystalline Texture Stress (PTS) goniometer; Scintag, Scintag Inc., Cupertino, CA, USA) using CuKα radiation generated at 45 kV and 36 mA. The CuKα radiation consists of Kα1 (0.15406 nm) and Kα2 (0.15444 nm) components, and the resultant XRD data has both components present; the CuKα radiation is filtered out from the data using a single-channel analyzer on the output from the semiconductor detector, and does not contribute to the data. The source slits were 2.0 mm and 4.0 mm at a 290 mm goniometer radius, and the detector slits were 1.0 mm and 0.5 mm at the same radius. Dried cellulose samples (approximately 0.5 g) were mounted onto a quartz substrate using several drops of diluted glue. This diluted glue is amorphous when it is dry, and adds almost no background signal (lower line in Figure 1a ). Scans were obtained from 5 to 50 degrees 2θ in 0.05 degree steps for 15 seconds per step.
To calculate the CI of cellulose from the XRD spectra, three different methods were used. First, CI was calculated from the height ratio between the intensity of the crystalline peak (I002 - IAM) and total intensity (I002) after subtraction of the background signal measured without cellulose [17 (link)-19 (link)] (Figure1a ). Second, individual crystalline peaks were extracted by a curve-fitting process from the diffraction intensity profiles [20 (link),21 (link)]. A peak fitting program (PeakFit; www.systat.com) was used, assuming Gaussian functions for each peak and a broad peak at around 21.5° assigned to the amorphous contribution (Figure 1b ). Iterations were repeated until the maximum F number was obtained. In all cases, the F number was >10,000, which corresponds to a R2 value of 0.997. Third, ball-milled cellulose (Figure 2c ) was used as amorphous cellulose to subtract the amorphous portion from the diffraction profiles [15 (link)] (Figure 1c ). After subtracting the diffractogram of the amorphous cellulose from the diffractogram of the whole sample, the CI was calculated by dividing the remaining diffractogram area due to crystalline cellulose by the total area of the original diffractogram.
Solid-state 13C NMR spectra were collected at 4.7 T with cross-polarization and magic angle spinning (MAS) in a 200 MHz spectrometer (Avance; Bruker, Madison, WI, USA). Variable amplitude cross-polarization was used to minimize intensity variations of the non-protonated aromatic carbons that are sensitive to Hartmann-Hahn mismatch at higher MAS rotation rates [22 ]. The 1H and 13C fields were matched at 53.6 kHz, and a 1 dB ramp was applied to the proton rotating-frame during the matching period. Acquisition time was 0.051 seconds, and sweep-width was 20 kHz. MAS was performed at 6500 Hz. The number of scans was 10,000 to 20,000 with a relaxation time of 1.0 seconds. The CI was determined by separating the C4 region of the spectrum into crystalline and amorphous peaks, and calculated by dividing the area of the crystalline peak (87 to 93 ppm) by the total area assigned to the C4 peak (80 to 93 ppm) [23 (link)] (Figure3a , Figure 3b ).
To calculate the CI of cellulose from the XRD spectra, three different methods were used. First, CI was calculated from the height ratio between the intensity of the crystalline peak (I002 - IAM) and total intensity (I002) after subtraction of the background signal measured without cellulose [17 (link)-19 (link)] (Figure
Solid-state 13C NMR spectra were collected at 4.7 T with cross-polarization and magic angle spinning (MAS) in a 200 MHz spectrometer (Avance; Bruker, Madison, WI, USA). Variable amplitude cross-polarization was used to minimize intensity variations of the non-protonated aromatic carbons that are sensitive to Hartmann-Hahn mismatch at higher MAS rotation rates [22 ]. The 1H and 13C fields were matched at 53.6 kHz, and a 1 dB ramp was applied to the proton rotating-frame during the matching period. Acquisition time was 0.051 seconds, and sweep-width was 20 kHz. MAS was performed at 6500 Hz. The number of scans was 10,000 to 20,000 with a relaxation time of 1.0 seconds. The CI was determined by separating the C4 region of the spectrum into crystalline and amorphous peaks, and calculated by dividing the area of the crystalline peak (87 to 93 ppm) by the total area assigned to the C4 peak (80 to 93 ppm) [23 (link)] (Figure
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Carbon
Carbon-13 Magnetic Resonance Spectroscopy
Cellulose
Neoplasm Metastasis
Protons
Quartz
Radionuclide Imaging
Radiotherapy
Radius
Reading Frames
Most recents protocols related to «Protons»
Example 14
The elemental composition of the Succinic acid-1,4-Butanediol-Malic acid copolyester was analyzed by Proton Induced X-ray Emission (PIXE) at Elemental Analysis Inc. This method provides quantitative elemental composition of a material for inorganic elements sodium through uranium on the periodic table. The elements found are shown in Table 7. The polymer did not contain detectable heavy metals such as Tin, which is sometimes used in the manufacture of resorbable polymers such as poly-glycolide, polylactide and poly-glycolide-co-lactide. The following trace elements were detected: silicon 18.98 ppm, titanium 14.77 ppm, and zinc 5.967 ppm.
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Butylene Glycols
malic acid
Metals, Heavy
poly(butylene succinate)
poly(lactide)
Poly A
Polymers
PPM 18
Protons
Roentgen Rays
Silicon
Sodium
Succinic Acid
Titanium
Trace Elements
Uranium
Zinc
EXAMPLE 1
OCG was synthesized and the average molecular weight of OCG was confirmed by both gel permeation chromatography (GPC) and proton nuclear magnetic resonance (H NMR) spectroscopy (
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Amines
Cell Lines
Cell Survival
Cytotoxin
Gel Chromatography
Guanidine
Hepatocellular Carcinomas
Homo sapiens
Macrophage
Magnetic Resonance Imaging
Mus
physiology
Protons
Spectroscopy, Nuclear Magnetic Resonance
Vertebral Column
Example 30
The typical protocol for the preparation of PNMEP28 macro-CTA is described below. NMEP (9.37 g, 47.4 mmol), CPDB RAFT agent (0.30 g, 1.36 mmol; target DP=35), ACVA (76.0 mg, 0.27 mmol; CPDB/ACVA molar ratio=5.0) and ethanol (14.59 g, 40% w/w solids) were weighed into a 50 mL round-bottom flask immersed in an ice bath and degassed with continuous stirring for 30 min. The reaction was allowed to proceed for 270 min in an oil bath set to 70° C., resulting in a monomer conversion of 90% as judged by 1H NMR spectroscopy. The polymerization was then quenched by exposing the hot reaction solution to air and cooling to 20° C. The crude polymer was precipitated into excess diethyl ether to remove residual monomer before freeze-drying in the minimum amount of water to afford a dry pink powder. The mean DP was calculated to be 28 by comparing the integrated aromatic protons arising from the CPDB RAFT agent. GPC analysis using chloroform eluent indicated an Mn of 5000 g mol−1 and Mw/Mn of 1.23 against a series of ten near-monodisperse poly(methyl methacrylate) calibration standards.
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Bath
Chloroform
Ethanol
Ethyl Ether
Methylmethacrylate
Molar
Poly A
Polymerization
Polymers
Powder
Protons
Spectroscopy, Nuclear Magnetic Resonance
Example 1
Reagents and starting materials were obtained by commercial sources unless otherwise stated and were used without purification.
Proton and carbon NMR spectra (as applies to Example 1) were acquired on either of a Bruker Biospin DRX 400 MHz FTNMR spectrometer operating at a 1H and 13C resonant frequency of 400 and 100 MHz respectively, or on a 300 MHz NMR spectrometer. One dimensional proton and carbon spectra were acquired using a broadband observe (BBFO) probe with 20 Hz sample rotation at 0.1834 and 0.9083 Hz/Pt digital resolution respectively. All proton and carbon spectra were acquired with temperature control at 30° C. using standard, previously published pulse sequences and routine processing parameters.
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Anabolism
Carbon
Fever
Fingers
Protons
Pulse Rate
pyrazole
Example 22
A method for preparing a gas diffusion layer for proton exchange membrane fuel cell, includes steps as follows:
-
- (1) preparing the carbon fiber suspension;
- mixing the carbon fiber dispersion with the fibrous binder dispersion, then adding the ceramic fiber of 1 mm length (zirconia fiber), and then shearing and dispersing at a high-speed rate of 1500 r/min to obtain the carbon fiber suspension;
- wherein the carbon fiber dispersion consists of the carbon fiber, the dispersant and water;
- wherein the fibrous binder dispersion consists of the fibrous binder, the dispersant and water;
- wherein the viscosity of dispersion composed of the dispersant and water is 2000 Pa·s in the carbon fiber suspension;
- wherein the dispersant is Tween 60; wherein the amount of the dispersant in the carbon fiber suspension is 1.5 wt % of the amount of water;
- wherein the fibrous binder is the composite filament numbered F-4 in Table 1;
- wherein the length of the carbon fiber is 10-20 mm, the aspect ratio of the carbon fiber is 100-3000, and the mass of carbon fibers with the aspect ratio in the interval [100, 500) accounts for 10 wt % of the total mass of carbon fibers, the mass of carbon fibers with the aspect ratio in the interval [500, 1000) accounts for 60 wt % of the total mass of carbon fibers, the mass of carbon fibers with the aspect ratio in the interval [1000, 2000) accounts for 25 wt % of the total mass of carbon fibers, and the mass of carbon fibers with the aspect ratio in the interval [2000, 3000] accounts for 5 wt % of the total mass of carbon fibers; wherein the amount of the carbon fiber in the carbon fiber suspension is 5 wt % of the amount of water;
- wherein the amount of the ceramic fiber is 5 wt % of the amount of the carbon fiber;
- (2) papermaking and drying the carbon fiber suspension to obtain the carbon fiber base paper;
- wherein the drying temperature is 140° C. and the drying time is 5 min;
- in the prepared carbon fiber base paper, wherein the content of the fibrous binder is 30 wt %;
- (3) cross-linking and curing of the carbon fiber base paper (hot-pressing cross-linking);
- wherein the temperature of hot-pressing cross-linking is 300° C., the time of hot-pressing cross-linking is 5 min, and the pressure applied to the carbon fiber base paper is 5 MPa;
- (4) carbonizing and graphitizing the cross-linked carbon fiber base paper under the protection of argon to obtain a gas diffusion layer for proton exchange membrane fuel cell;
- wherein the carbonization temperature is 1250° C. and the carbonization time is 15 min; wherein the graphitization temperature is 2000° C. and the graphitization time is 5 min.
The prepared gas diffusion layer for proton exchange membrane fuel cell has hydrophilic channels composed of the ceramic fiber, and the pore gradient (that is, the pore size increases or decreases along the thickness direction), and the layer with the smallest pore size is the intrinsic microporous layer; wherein the gas diffusion layer for proton exchange membrane fuel cell has a thickness of 100 μm, a porosity of 70%, a contact angle with water of 145°, a tensile strength of 30 Ma, a normal resistivity of 70 mΩ·cm, an in-plane resistivity of 7 mΩ·cm, and a permeability of 2060 (mL·mm)/(cm2·h·mmAq).
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A 145
Argon
Carbon Fiber
Cytoskeletal Filaments
Diffusion
Fibrosis
Permeability
Pressure
Protons
Tween 60
Viscosity
zirconium oxide
Top products related to «Protons»
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Topspin 3.2 is a software package developed by Bruker for the acquisition, processing, and analysis of nuclear magnetic resonance (NMR) data. It provides a comprehensive suite of tools for the management and interpretation of NMR spectra.
Sourced in United States
The Ion Proton sequencer is a next-generation DNA sequencing platform developed by Thermo Fisher Scientific. It utilizes semiconductor-based sequencing technology to perform high-throughput, massively parallel DNA sequencing. The Ion Proton sequencer is designed to generate sequence data rapidly and cost-effectively.
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The Ion Total RNA-Seq Kit v2 is designed for library preparation and sequencing of total RNA samples using the Ion Torrent sequencing platform. The kit enables the preparation of cDNA libraries from total RNA for subsequent sequencing on the Ion Torrent system.
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The Avance III is a high-performance NMR spectrometer by Bruker. It is designed for advanced nuclear magnetic resonance applications, providing reliable and accurate data acquisition and analysis capabilities.
Sourced in United States, Sweden
The Ion Proton System is a next-generation semiconductor-based DNA sequencing platform designed for high-throughput, scalable, and cost-effective genetic analysis. The core function of the system is to perform massively parallel sequencing of DNA samples using semiconductor-based technology.
Sourced in United States, Canada
The Ion Proton is a next-generation sequencing (NGS) system designed for high-throughput DNA sequencing. It utilizes semiconductor-based technology to perform sequencing-by-synthesis, enabling rapid and accurate DNA analysis. The Ion Proton system is capable of generating high-quality sequence data for a wide range of applications, including genome sequencing, transcriptome profiling, and targeted gene panels.
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MATLAB is a high-performance programming language and numerical computing environment used for scientific and engineering calculations, data analysis, and visualization. It provides a comprehensive set of tools for solving complex mathematical and computational problems.
Sourced in Germany, United States, Switzerland, Italy, France
The Avance III spectrometer is a nuclear magnetic resonance (NMR) spectrometer developed by Bruker. It is designed to perform high-resolution NMR analysis of chemical samples. The Avance III spectrometer provides advanced hardware and software features to enable precise data acquisition and analysis.
Sourced in Germany, United States, United Kingdom
TopSpin is a software package developed by Bruker for the control and processing of nuclear magnetic resonance (NMR) spectrometers. It provides the user interface and essential functionalities for the acquisition, processing, and analysis of NMR data.
Sourced in Germany, United States, United Kingdom, Switzerland, France
The Avance spectrometer is an analytical instrument designed for nuclear magnetic resonance (NMR) spectroscopy. It is capable of generating and detecting radio frequency signals to analyze the structure and properties of chemical compounds. The Avance spectrometer provides high-resolution data for a variety of NMR applications.
More about "Protons"
Protons are fundamental subatomic particles that are the building blocks of atomic nuclei.
These positively charged particles have a mass approximately 1,836 times greater than that of an electron.
Protons play a crucial role in the structure and stability of atoms, and their interactions with other particles are essential to many physical and chemical processes.
Protons can be accelerated to high energies and used in a variety of scientific applications, including particle physics research, medical imaging, and cancer therapy.
Understanding the properties and behavior of protons is a key area of study in fields such as nuclear physics, astrophysics, and quantum mechanics.
The Ion Proton sequencer and Ion Total RNA-Seq Kit v2 are examples of technologies that utilize protons in their functionality.
The Avance III spectrometer and TopSpin software from Bruker are also tools that enable the study and analysis of protons and other subatomic particles.
In addition, the Ion Proton System and MATLAB are platforms that can be used to manipulate and analyze data related to protons and their interactions.
The Avance III and Avance spectrometers from Bruker are also important instruments for the study of protons and other subatomic particles.
Overall, the understanding and application of protons is a critical component of many scientific disciplines, and the continued development of technologies and tools for their study and utilization is an ongoing area of research and innovation.
These positively charged particles have a mass approximately 1,836 times greater than that of an electron.
Protons play a crucial role in the structure and stability of atoms, and their interactions with other particles are essential to many physical and chemical processes.
Protons can be accelerated to high energies and used in a variety of scientific applications, including particle physics research, medical imaging, and cancer therapy.
Understanding the properties and behavior of protons is a key area of study in fields such as nuclear physics, astrophysics, and quantum mechanics.
The Ion Proton sequencer and Ion Total RNA-Seq Kit v2 are examples of technologies that utilize protons in their functionality.
The Avance III spectrometer and TopSpin software from Bruker are also tools that enable the study and analysis of protons and other subatomic particles.
In addition, the Ion Proton System and MATLAB are platforms that can be used to manipulate and analyze data related to protons and their interactions.
The Avance III and Avance spectrometers from Bruker are also important instruments for the study of protons and other subatomic particles.
Overall, the understanding and application of protons is a critical component of many scientific disciplines, and the continued development of technologies and tools for their study and utilization is an ongoing area of research and innovation.