Laser Photocoagulation Principles
John P. Papp in Endoscopie Control of Gastrointestinal Hemorrhage, 2019
where h is Plack’s constant, c is the speed of light, and ≈ is the wavelength. Thus, light of a particular wavelength may be viewed as a collection of photons of equal energy. By carefully noting (using absorption spectroscopy) which energy of photons are absorbed by a particular atom, the chemist is able to identify the atom under scrutiny because its “signature” is known. Likewise, the photons which an atom is capable of emitting are energetically related to its own particular quantum levels or energies. Spectroscopy which uses the emission signature of an atom is referred to as emission spectroscopy. Sometimes the emission is forced using a spark or flame in an atmosphere of the atom being tested. The emission of light by an atom can occur at any time provided it has a lower energy state which nature allows for it. The fact that the emission can occur at any time means that the scientist must use a statistical estimate of the likelihood of emission, rather than an absolute prediction of the occurrence. This kind of statistical emission is referred to as “spontaneous emission”.
Light, Matter, and Spectroscopy
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk in Survival Guide to General Chemistry, 2019
An electron can emit one photon to move from an initial higher electron energy level to a final lower energy level. Emission spectroscopy measures the wavelengths of light photons that are emitted during electron transitions in an atom. The electron(s) in the atom reach a higher energy level through other added energy such as heat or electricity. The emitted photon wavelengths (colors, if in the visible region of the spectrum) appear as bright (colored) lines against a dark background of all other non-emitted wavelengths of light.
Dictionary
Mario P. Iturralde in Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990
Absorption spectrum. The array of absorption lines and absorption bands which results from the passage of radiant energy from a continuous source through a selectively absorbing medium cooler than the source. The absorption spectrum is a characteristic of the absorbing medium just as an emission spectrum is a characteristic of a radiator. When the absorbing medium is in the solid or liquid state the spectrum of the transmitted light shows broad, dark regions which are not resolvable into lines and have no sharp or distinct edges.
Development of tibulizumab, a tetravalent bispecific antibody targeting BAFF and IL-17A for the treatment of autoimmune disease
Published in mAbs, 2019
Robert J. Benschop, Chi-Kin Chow, Yu Tian, James Nelson, Barbra Barmettler, Shane Atwell, David Clawson, Qing Chai, Bryan Jones, Jon Fitchett, Stacy Torgerson, Yan Ji, Holly Bina, Ningjie Hu, Mahmoud Ghanem, Joseph Manetta, Victor J. Wroblewski, Jirong Lu, Barrett W. Allan
ANS titrations were conducted to investigate whether disulfide bond stabilization reduced the exposure of the variable heavy and light chain hydrophobic interface residues. Anti-IL-17 scFv with or without an H44-L100 disulfide bond was diluted to 0.28 mg/mL in PBS buffer at pH 7.4. ANS was prepared as 1 mM stock solution in PBS buffer. The fluorescence emission spectrum was collected at 25°C from 400 nm to 700 nm, with a step size of 3 nm following excitation at 360 nm. Fluorescence measurements were made using an ISS PC1 fluorometer (Champaign, IL) equipped with a xenon lamp. The emission spectrum was recorded as a function of increasing concentration of ANS from 2 μM to 300 μM. Sequential ANS additions were performed followed by a brief mixing step, incubation, and collection of the emission spectra at approximately 2 min. intervals. A similar protocol was followed for the parent and H44-L100 scFv. The background of the buffer was subtracted from the sample spectrum at each corresponding concentration of ANS.
Pendant HDAC inhibitor SAHA derivatised polymer as a novel prodrug micellar carrier for anticancer drugs
Published in Journal of Drug Targeting, 2018
Jieni Xu, Jingjing Sun, Pengcheng Wang, Xiaochao Ma, Song Li
The critical micelle concentration (CMC) of POEG-b-PSAHA was measured by fluorescence spectrometry using nile red as a fluorescence probe. Briefly, thirty microlitres of nile red (0.05 mg/mL in DCM) were added to each tube and the solvent was removed by nitrogen flow. POEG-b-PSAHA micelles ranging from 6.1 × 10−5 to 5 × 10−1 mg/mL were prepared with serial dilution as described above and then added into the tubes with nile red. The final concentration of nile red was kept at 6.0 × 10−7 M. The micelles were vortexed and kept overnight at room temperature to reach the equilibrium of solubilisation. The samples were excited at an excitation wavelength of 550 nm and fluorescence intensities were recorded at an emission spectrum from 600 to 700 nm. The peak intensities at 647 nm were plotted versus polymer concentrations. The CMC value was calculated as the cross-point where a sharp increase in fluorescence intensity was observed.
Antimicrobial mechanism and the effect of atmospheric pressure N2 plasma jet on the regeneration capacity of Staphylococcus aureus biofilm
Published in Biofouling, 2018
Jiaquan Wang, Zhiyuan Yu, Zimu Xu, Shuheng Hu, Yunxia Li, Xiaojuan Xue, Qiuchen Cai, Xiaoxia Zhou, Jie Shen, Yan Lan, Cheng Cheng
Optical emission spectroscopy (OES) was adopted to detect the parameters of the N2 APPJ and the related information was provided in previous studies (Xiao et al. 2014, 2016). The OES result (200–1050 nm) of the N2 plasma jet shows the emission lines of N2 (337.1 nm), N2+ (391.4 nm), excited OH (309 nm) and atomic oxygen O (777.2 nm). Specifically, these excited RS such as OH and O which could damage microbial structures through oxidation, thus producing better antimicrobial effects.
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