China
Africa
Explore chapters and articles related to this topic
Understanding the Role of Existing Technology in the Fight Against COVID-19
Published in Ram Shringar Raw, Vishal Jain, Sanjoy Das, Meenakshi Sharma, Pandemic Detection and Analysis Through Smart Computing Technologies, 2022
Raman spectroscopy is another highly sensitive and useful vibrational spectroscopy technique that allows non-destructive and real-time analysis of biological samples. A Raman spectrum is obtained by the process of scattering of light, whereas in FTIR, it is obtained by absorption of light by the matter. When a monochromatic (laser source) light is incident on the sample, the light may interact with the material either elastically or inelastically. In the elastic scattering, the incident photon is absorbed and reemitted with the same energy (frequency). This is known as Rayleigh scattering. On the other hand, in an inelastic scattering, the absorbed photon may be emitted with frequency higher or lower than the incident photon. The probability of inelastic scattering is very small compared to the Rayleigh scattering. The process of light scattering is shown in Figure 2.4. When the frequency of emitted photon (ν2) is less than the incident frequency (ν1), it is known as Stokes Raman scattering. When the frequency of emitted photon (ν2) is more than the incident frequency (ν1), it is known as anti-Stokes Raman scattering. This phenomenon is known as the Raman effect, and the observed effect is specific to the molecules causing the scattering. Thus, the Raman signals are used for determining the presence of molecules and their states using the inelastic scattering.
Ion Beam Analysis: Analytical Applications
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
Barrandon and Seltz (1973) have described a method for the microanalysis of carbon on the surface of metal samples by the detection of protons from the (t, p) reaction at bombarding energies below 2 MeV. For the reaction 12C(t, p)14C, Q = 4.641 MeV, the cross-sections for optimal bombarding energies Et = 1.930 and 1.740 MeV are dσ/dΩ (θ = 160°) = 12.36 mb/sr and dσ/dΩ (θ = 150°) = 4.05 mb/sr, respectively. A large number of γ-rays can be produced in the process of the bombardment of 13C nucleus by differently charged particles. Inelastic scattering can generate some characteristic γ-rays. The 13C(p, γ)14N reaction has several narrow low-energy resonances corresponding to 14N excited states. A large number of γ-rays is also produced in 13C(d,n)14N and 13C(d,p)14C reactions. The γ-rays produced are due to the transitions involving excited states of 14N and 14C nuclei.
Interactions of Uncharged Particles with Matter
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
David R. Dance, J.-C. Rosenwald, Gudrun Alm Carlsson
When the neutrons have been slowed down to less than 20 keV (i.e. becoming epithermic neutrons), although inelastic scattering still predominates, capture by the nucleus becomes progressively more probable as the neutron energy decreases.
Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects
Published in Expert Opinion on Drug Delivery, 2023
Shirleen Miriam Marques, Lalit Kumar
Raman spectroscopy is a powerful method that enables the deduction of the chemical composition of membranes which can reveal the structure to a great extent. This spectroscopic method is founded on the inelastic scattering of monochromatic light that originates from a laser source [174,175]. De Waard and coworkers fabricated a new technique, ‘controlled crystallization during freeze-drying,’ to develop drug nanocrystals of poorly water-soluble drugs. The crystallization process during freeze-drying was monitored with a Raman probe positioned over the sample placed in the freeze-dryer. The in-line Raman spectroscopy measurements indicated the crystallization of the various constituents during freeze-drying. At a high freezing level, the small interstitial gaps containing the freeze-concentrated components were produced, producing a drug crystal with a smaller size [176].
Comparison of clinical efficacy of three different dentin matrix biomaterials obtained from different devices
Published in Expert Review of Medical Devices, 2023
Robert Dłucik, Bogusława Orzechowska-Wylęgała, Daniel Dłucik, Domenico Puzzolo, Giuseppe Santoro, Antonio Micali, Barbara Testagrossa, Giuseppe Acri
Four samples for each device and four non-demineralized controls were used for the examination with SEM, EDX analysis, and Raman spectroscopy. The non-demineralized samples were cut into two halves and used as dentin control. The SEM analysis evaluated the morphology of the granular material obtained with each device. It was coupled with EDX spectroscopy microanalysis to determine the elemental composition of the sample surface. Furthermore, Raman spectroscopy, belonging to the family of vibrational spectroscopic techniques, was also performed on the different specimens. It is a spectroscopic modality based on the inelastic scattering process of monochromatic light [24]. It is a rapid and nondestructive analysis technique for the detection of biochemical changes at the molecular level and does not require any preparation before the measurement [25]. It represents a useful methodology in various research fields, such as physics, human and veterinary medicine, chemistry, and material science [26–28]. These techniques have a large number of applications in various industrial, commercial, and research fields [29,30].
In Vivo Corneal Stiffness Mapping by the Stress-Strain Index Maps and Brillouin Microscopy
Published in Current Eye Research, 2023
Bernardo T. Lopes, Ahmed Elsheikh
Brillouin Microscopy (BM) is an imaging modality based on the inelastic scattering that arises from the interaction of light with the medium’s inherent acoustic phonons—or density fluctuations.25 The Doppler effect that arises from the reflection of light waves by these progressive inherent sound waves denominates the Brillouin shift.25 Given that the refractive index and density of the material are known, the Brillouin frequency shift can be explicitly converted to the sample’s longitudinal modulus (M’) using the following relationship: Ω is the frequency shift of the scattered light, λ is the wavelength of the incident photons, ρ is the density of the material and n is the refractive index of the material.26 The method to estimate the longitudinal modulus assumes mechanical isotropy of corneal tissue.26