2017年2月7日星期二

Cryogenic Nanopore NMR Analyzer

NMRC12 series is a NMR-based nano-pore analyzer used to study the pore structure and distribution of porous materials. The determination of pore distribution can be measured and calculated by applying the relationship between the pore size and the freezing point of pore fluid. This NMR technique could be used to monitor the phase transition in pore fluid in real time and the detection range of pore size falls in 2 to 500 nm if appropriate fluid samples are chosen.
Application Indexes
Temperature range: – 30 0C~ 40 0C/ – 50 0C~ 40 0C (accuracy: ± 0.01 0C);
Cooling rate:10C / min;
Sample volume: 0.5 cm3 ~ 1 cm3;
Pore size: 2 nm ~ 500 nm.
Static fluid in pores improves the accuracy and resolution during the measuring course of cryogenic NMR method;
The modular gas supply system provides a stable and dry air flow as the media, which reduces signal minimum and can work for a long period of time;
Ultra-low temperature thermostat system at – 60 0C gurantees a stable cooling source which can cool down the air flow quickly and stablize it;
Two-stage heating resistors heat the sample chamber rapidly and control the temperature precisely;
NMR analyzer system with mature technology and full NMR capabilities: stable magnetic field, short dead time, and high SNR;
Probe designed for low temperature isolates the heat exchanges between sample chamber and the magnet effectively;
The powerful software with friendly user interface offers a fully automated solution including calculation, temperature setting, sampling, and data process plus figure exporting.

2017年2月6日星期一

EDUVMR NMR & MRI System

The EDUMR virtual data acquisition and image reconstruction teaching software is a low-field magnetic resonance analyzing and imaging simulation system combining NMR and MRI system all in one. By using this virtual NMR analyzer signal acquisition and image processing software, we can easily build up a teaching platform, and the realistic teaching of NMR principles and techniques become much more achievable. The virtual magnetic resonance imaging system can simulate the entire process. With the parameter driven interface users can select imaging sequence, the original level and imaging technology, carry out the relevant data collection process and perform K space filling of reconstructed images. The use of virtual systems allows many students to learn simultaneously without the need to invest in expensive hardware or several supervisors to train users.
Advantages
EDUVMR
Perform virtual sequence selection, parameter adjustment, data acquisition, K space filling, image reconstruction function; The influence of magnetic field in homogeneity and electronic noise can be simulated; Minimal investment in hardware is an advantage; Perform fat suppression imaging; Perform water suppression imaging; Perform Bounce-point Imaging; Perform Half-Fourier scanning &Imaging; Overcomes the problem of long time of acquisition through inadequate instrumentation; More than four pulse sequences (SE sequence), FSE sequence, IR sequence, GRE sequence) can be used for virtual imaging data collection; Observe how the scan parameters affect the image; Minimize the impact of gradient eddy current, analog acquisition in severe T2-weighted images; Adjust the data acquisition to a normal speed and a very-fast speed.

2017年2月5日星期日

Difference Between T1 and T2 Imaging in MRI?

T1 is a rate of longitudinal relaxation. When we tip the magnetization in tissue away from its alignment with the scanner’s magnetic field, it takes a little bit of time for it to go back to its equilibrium low energy. That rate of change is T1.
T2 is a rate of transverse relaxation. I think “spin-spin” is a confusing term, though it is commonly used. After we tip magnetization away from its alignment with the field axis, it precesses (rotates) around that axis, kinda like a gyroscope or a precessing spinning top. Neighboring ensembles don’t have the exact same precession frequency. There is a spread in these frequencies. Therefore, neighboring ensembles accumulate a phase relative to each other resulting in their signals gradually cancelling each other out, until the signal disappears. This rate of change is T2 (actually, it’s T2* – “Tee two star”, which is strongly related to T2).
T1 is different in different tissue types, as is T2, and T2*. These values also change with some pathology. relaxation rates are one form of tissue contrast. We can get an image that’s T1-weighted, or we can actually do a fitting and get a quantitative T1 map. The same is true for T2 or T2*. We can get a qualitative T2-weighted image, or a quantitative T2 map. I think radiologists need to get used to the quantitative maps, as the qualitative data may not be as reliable, and doesn’t represent a precise measurement. It can vary substantially based on measurement conditions and the setup. Yet, change apparently is tough – radiologists still rely heavily on qualitative data instead of the alternative, which actually can be used to make statistical inferences.
Image contrast is the goal in all imaging procedures. The imaging technique will emphasize certain contrast characteristics of anatomical structures and allow us to differentiate the structures and determine which structures are abnormal.
MRI structural image contrast is natively (i.e. without using contrast enhancing agents) superior than CT and other imaging techniques. In both CT and MRI system, image contrast is a function of tissue density. For MRI in which the source of signal are the protons (especially hydrogen protons), the type of density that matters the most is proton density. In addition to tissue density, tissue relaxation properties contribute to image contrast in MRI (but not CT). There are two types of relaxation properties: T1 relaxation and T2 relaxation. Both types have been correctly described by the other responders but let me state it in a slightly different way. During the process of T1 relaxation, protons reorient resulting in recovery of longitudinal magnetization. During the process of T2 relaxation, protons dephase (spin becomes desynchronized) resulting in decay of transverse magnetization.

2017年1月23日星期一

Solid Fat Content NMR Measurement

Solid Fat Content is the percentage of solids in fat at specified temperatures. Solid Fat Content (SFC) is an important characteristic that can influence appearance, flavor release, melt rate, shelf life and stability of fat based food products. In the chocolate industry it is desirable to manufacture products with the ideal Solid Fat Content that will allow for chocolate to remain solid at room temperature, but still give consumers that “melt in your mouth” experience. Knowing various characteristics of your product from solid fat content allows you to direct your manufacturing processes in a way that achieves the highest quality products.
The measurement of solid fat content (SFC) within the baking, confectionary and margarine industries is crucial as fats are a key component in many processed foodstuffs produced within these industries. Fats are complex ingredients which play a key role in nutrition and consumer appeal of products. Measurement of solid fat content (SFC) is the industry standard approach to understanding the melting behaviour of edible oils and fats. The reason this is so important is that the melting profile of fats is one of the parameters which must be carefully controlled to ensure consistent products.
Solid Fat Content (SFC) determination is of prime importance for food processing and development.
Raw materials like fat compositions or blends need to be characterized and controlled according to their melting profiles. The SFC determination by time domain (TD) NMR analysis is the internationally recognized standard method. In a close partnership with the oil & fat industry spanning more than 4 decades we has developed its dedicated SFC Analyzer. All types of SFC methods are supported by the PQ001,including direct/indirect and parallel/serial methods.
The TD-NMR analysis provides a quick, non-destructive and solvent-free measurement. We also offers a fully automated solution including tempering procedures,NMR analyzer measurement, and determination of the SFC value plus presentation of the melting curve.
Solid Fat Content analysis is important for food manufacturers that produce fat based food products. Dynalene provides reliable solid fat content analysis with a quick turnaround time. With our top of the line DSC, Dynalene has the ability to test your fat based foods.

2017年1月22日星期日

Applications of NMR to Food Science

Nuclear magnetic resonance (NMR) spectroscopy is one of the most common investigative techniques used by both chemists and biochemists to identify molecular structures as well as to study the progress of chemical reactions. Magnetic resonance imaging (MRI), another type of NMR technology, has extensively been used in medical radiology to obtain soft tissue images for diagnostic purposes in medicine.

Food scientists have also explored the use of both NMR and MRI and continue to develop a wide range of applications for food NMR analyzer and food processing. This review begins with a brief introduction to NMR and then focuses on current diverse NMR applications in food research and manufacturing.

Topics covered include chemical compositional analysis and structural identification of functional components in foods, determination of composition and formulation of packaging materials, detection of food authentication, optimization of food processing parameters, and inspection of microbiological, physical and chemical quality of foods. This review also emphasizes the pros and cons of specific NMR application in the analysis of representative foods such as wine, cheese, fruits, vegetables, meat, fish, beverages (i.e. tomato juice and pulp, green tea, coffee) and edible oils, as well as discussing both the challenges and future opportunities in NMR applications in food science.

This report reviews the literature on the applications of NMR to food science from 1995 until March 2001. In order to be able to keep the number of references to manageable proportions, the number of papers referred to has been limited to those applications where NMR plays a major role in the experimental programme. Applications where NMR is simply used as a routine structural tool have been left out. Following an introductory section, the report covers water in foods, biopolymers, analysis and authentication, complex systems, and new methods for food analysis.

2017年1月21日星期六

Porous Media NMR Analysis

Recent years have seen a significant progress in the study of porous media of natural and industrial sources. This paper provides a brief outline of the recent technical development of NMR in this area. These progresses are relevant for NMR application in material characterization.
The wettability conditions in a porous media containing two or more immiscible fluid phases determine the microscopic fluid distribution in the pore network. Nuclear magnetic resonance measurements are sensitive to wettability because of the strong effect that the solid surface has on promoting magnetic relaxation of the saturating fluid. The idea of using NMR as a tool to measure wettability was presented by Brown and Fatt in 1956. The magnitude of this effect depends upon the wettability characteristics of the solid with respect to the liquid in contact with the surface.Their theory is based on the hypothesis that molecular movements are slower in the bulk liquid than at the solid-liquid interface. In this solid-liquid interface the diffusion coefficient is reduced, which correspond to a zone of higher viscosity. In this higher viscosity zone, the magnetically aligned protons can more easily transfer their energy to their surroundings. The magnitude of this effect depends upon the wettability characteristics of the solid with respect to the liquid in contact with the surface.
NMR Cryoporometry (NMRC) is a recent technique for measuring total porosity and pore size distributions. It makes use of the Gibbs-Thomson effect : small crystals of a liquid in the pores melt at a lower temperature than the bulk liquid : The melting point depression is inversely proportional to the pore size. The technique is closely related to that of the use of gas adsorption to measure pore sizes (Kelvin equation). Both techniques are particular cases of the Gibbs Equations (Josiah Willard Gibbs): the Kelvin Equation is the constant temperature case, and the Gibbs-Thomson Equation is the constant pressure case.
To make a Cryoporometry measurement, a liquid is imbibed into the porous sample, the sample cooled until all the liquid is frozen, and then warmed slowly while measuring the quantity of the liquid that has melted. Thus it is similar to DSC thermoporosimetry, but has higher resolution, as the signal detection does not rely on transient heat flows, and the measurement can be made arbitrarily slowly. It is suitable for measuring pore diameters in the range 2 nm–2 μm.
Nuclear Magnetic Resonance (NMR) may be used as a convenient method of measuring the quantity of liquid that has melted, as a function of temperature, making use of the fact that the {\displaystyle T_{2}} T_{2} relaxation time in a frozen material is usually much shorter than that in a mobile liquid. The technique was developed at the University of Kent in the UK.It is also possible to adapt the basic NMRC experiment to provide structural resolution in spatially dependent pore size distributions, or to provide behavioural information about the confined liquid.porous media NMR

2017年1月18日星期三

Small Animal MRI

Atlas of Small Animals MRI is a highly illustrated guide to the common clinical disorders of dogs and cats that are now routinely diagnosed using computed tomography and magnetic resonance imaging. This invaluable new resource features a wealth of high-quality CT and MRI images and includes relevant radiographic, ultrasonographic, endoscopic, and gross pathology images, offering a unique approach emphasizing comparative imaging and pathologic correlation.

The book is organized by anatomical region with subsections focusing on specific anatomical sites or disorders—from the head, neck, brain and spine to the thorax, abdomen, and musculoskeletal system. The accompanying text emphasizes important imaging features focusing on what is important to the diagnosis of disease. Where helpful to the imaging diagnosis, information related to disease etiopathology, non-imaging diagnostic procedures, and treatment is also included.

Essential for specialists in training and qualified specialists in the fields of small animal veterinary diagnostic imaging, internal medicine, and surgery. Also of interest to those in general veterinary practice who commonly refer patients for CT and MRI examinations.

Atlas of Small Animal CT & MRI is a highly illustrated diagnostic imaging guide to common clinical disorders of dogs and cats.
Contains over 3,000 high quality CT, MRI and related diagnostic images
Offers a unique approach emphasizing comparative imaging and pathologic correlation
Focuses on important imaging features relevant to imaging diagnosis of disease in dogs and cats
Written by internationally renowned experts in the field