Efficacy S-formula and Kinetics of Non-oxygen-mediated (Type-I) and Oxygen-mediated (Type-II) Corneal Cross-linking

2018 ◽  
Vol 8 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Jui-Teng Lin
Keyword(s):  
Cross Linking ◽  
Type I ◽  
Type Ii ◽  
Kinetics Of

Cellular studies of peripheral neurons in siphon skin of Aplysia californica

1979 ◽  
Vol 42 (2) ◽  
pp. 530-557 ◽  
Author(s):  
C. H. Bailey ◽  
V. F. Castellucci ◽  
J. Koester ◽  
E. R. Kandel
Keyword(s):  
Motor Neurons ◽  
Synaptic Input ◽  
Firing Pattern ◽  
White Cell ◽  
Type I ◽  
Type Ii ◽  
Peripheral Neurons ◽  
Peripheral Neuron ◽  
Type I Neuron ◽  
Kinetics Of

1. To account for the similarity in the kinetics of habituation between the central and peripheral components of siphon withdrawal, we have tested the idea (52) that each centrally located mechanoreceptor sensory neuron sends two branches to siphon motor neurons; one to centrally located siphon motor neurons and a collateral branch that remains in the periphery and innervates the peripheral siphon motor neurons. 2. We have found a group of peripheral siphon motor neurons and tested the connection onto these cells by central mechanoreceptors. In addition, we have defined by various electrophysiological and morphological criteria two general classes of peripheral neurons that lie along the course of the siphon nerve. 3. One class (type I) consists of only a single cell in each animal. This peripheral neuron typically has the largest cell body found lying along the siphon nerve and is the only peripheral nerve cell that appears white when viewed under epi-illumination. The type I neuron often has a highly regular firing pattern, which occurs in the absence of spontaneous synaptic input. The three-dimensional morphology of this neuron suggests a paucity of fine processes, most of which do not arborize and may terminate in the connective tissue sheath. Fine structural observations of the peripheral white cell have revealed the presence of large densecore granules. The peripheral type I neuron is similar in most of its electrophysiological and morphological properties to central neurons postulated to be neurosecretory. The peripheral white cell is, at present, the only peripheral neuron we can identify with certainty as a unique individual. 4. The second class (type II) of peripheral neurons are siphon motor neurons for the peripheral component of the siphon-withdrawal reflex. In contrast to the type I neurons, members of the second class of peripheral neurons possess smaller, more spherical cell bodies that have varying amounts of orange pigmentation and which give rise to a relatively well-developed and arborized dendritic tree. Type II neurons feature an irregular spontaneous firing pattern that is occasionally modulated by a rich spontaneous synaptic input. Peripheral siphon motor neurons have restricted motor fields that produce contraction of the mantle floor and the base of the siphon. Most of the type II neurons were found to be electrically coupled to one another. 5. The peripheral siphon motor neurons resemble the central siphon motor neurons in that they receive a collateral synapse from centrally located mechanoreceptor sensory neurons. This peripheral sensory-to-motor synapse exhibits the same kinetics of decrement as its central counterpart, both of which parallel behavioral habituation. 6. The rich mechanoreceptor input onto the relatively isolated dendritic trees of the peripheral siphon motor neurons provide a uniquely restricted neuropil to study the sensory-to-motor synapse. The peripheral motor neurons may, therefore, be a useful simple preparation for the cellular study of behavioral plasticity.

The absorption spectra of irradiated diamonds after heat treatment

1956 ◽  
Vol 237 (1208) ◽  
pp. 75-89 ◽  
Keyword(s):  
Absorption Spectra ◽  
Absorption Lines ◽  
Type I ◽  
Type Ii ◽  
Large Reduction ◽  
Isothermal Heating ◽  
Interstitial Carbon ◽  
Crystal Imperfections ◽  
Continuous Absorption ◽  
Kinetics Of

The absorption spectra of eight type I and three type II a diamonds irradiated with neutrons, electrons or y-rays have been recorded at 80 and 290°K after various heat treatments in the temperature range 0 to 900°C. It is found that heating in the range 350 to 450°C causes a general reduction in the irradiation-induced absorption owing to the recombination of those interstitials and vacancies which are near neighbours. Heating type II a diamonds at 600°C causes a large reduction in the irradiation-induced lines and new lines appear. These are probably due to pairs of identical defects, and the kinetics of their formation during isothermal heating at 600°C are presented. At higher temperatures all absorption lines in type II a diamonds disappear and only continuous absorption remains. This is probably due to amorphous or graphitic regions produced by agglomeration of defects. Type I diamonds show the same kind of absorption, but in addition show an increase in strength of the natural lines and also some new absorption lines which are not removed by heating at 900°C. It is suggested that these additional processes are due to the anchoring of vacant atomic sites and interstitial carbon atoms at crystal imperfections present only in type I diamonds.

scholarly journals Physiological and Clinical Significance of Disordered Cross-Linking of Fibrin

1977 ◽  
Author(s):  
L. Lorand
Keyword(s):  
Class Ii ◽  
Class I ◽  
Cross Linking ◽  
Type I ◽  
Type Ii ◽  
Zymogen Activation ◽  
Primary Defect ◽  
Plasma Clot ◽  
Autoimmune Antibodies ◽  
Hereditary Disorders

Disorders of fibrin stabilization are hemorrhagic conditions in which the patient’s plasma clot is lacking in inter-fibrin γ-glutamyl-ε-lysine isopeptide linkages. The primary defect occurs either because no fibrinoligase (FXIIIa) activity can be generated or because the enzyme cannot act on fibrin in the patient’s plasma. Distinction is made between hereditary disorders (Class I) and those appearing later in life because of an acquired inhibitor (Class II) directed against one of the steps on the pathway of fibrin stabilization: Of the genetic deficiencies (Class I), Type I is characterized by a lack of zymogen activity in plasma and Type II by the unreactivity of the cross-linking sites of the patient’s fibrin [“dysfibrin(ogen)emias”] towards fibrinoligase.There are three varieties of Class II abnormalities. In Type I, the acquired inhibitor interferes with zymogen activation. Type II inhibitors affect transamidation by competing against fibrin for the enzyme. The Type III inhibitor combines with fibrin rendering it unreactive towards fibrinoligase. The Type I and III inhibitors appear to be autoimmune antibodies.(Ann. N. Y. Acad. Sei., 202, 6, 1972).Differential diagnostic criteria for this family of molecular disorders will be discussed.

scholarly journals Critical Analysis of Corneal Cross-linking (Part-II): Resolving the Controversial Issues (Theory versus Measurements)

2021 ◽  
pp. 23-34
Author(s):  
Jui-Teng Lin
Keyword(s):  
Light Intensity ◽  
Scaling Laws ◽  
Uv Light ◽  
Corneal Thickness ◽  
Cross Linking ◽  
Type I ◽  
Controversial Issues ◽  
Type Ii ◽  
Stromal Tissue ◽  
New Vision

Aims: To resolve the controversial issues of UV-light-initiated corneal collagen cross-linking (CXL) by theoretical formulas and measured clinical outcomes. Study Design:  Analysis and measured data of CXL. Place and Duration of Study: New Vision Inc, Taipei, between June 2021 and August 2021. Methodology: The controversial issues are addressed and resolved by analytical formulas including: the validation of Bunsen Roscoe law (BRL), the cutoff light intensity, the minimum corneal thickness, the demarcation line depth, the role of oxygen and riboflavin concentration. The overall CXL efficacy is governed by UV-A light intensity, dose, exposure time, mode of exposure (pulsed or CW), the riboflavin concentration, diffusion and drops pre-operation and interoperation administration, the concentration of oxygen in the stromal tissue (pre-op and inter-op), and environmental conditions. The length of the riboflavin presoaking time and viscosity of the riboflavin film also affect the crosslink depth. Analytic formulas are derived for the scaling laws for type-I and type-II efficacy, given by the square root of light intensity, and light dose, respectively. Conclusion: The controversial issues of CXL may be partially resolved via analytic formulas, and compared with measurements. The scaling laws of type-I and type-II efficacy are different and given by analytic formulas. Our formulas also predict the maximum light intensity and the minimum corneal thickness, which are consistent with measurements.

The photolysis of polymethylvinylketone. I. Reactions and kinetics

1955 ◽  
Vol 233 (1193) ◽  
pp. 153-172 ◽  
Keyword(s):  
Molecular Weight ◽  
Ultra Violet ◽  
Type I ◽  
Type Ii ◽  
Weight Changes ◽  
Violet Light ◽  
Aliphatic Ketones ◽  
Primary Reactions ◽  
Acetyl Radical ◽  
Kinetics Of

The photolysis of polymethylvinylketone has been studied in solution. The two primary reactions which occur upon absorption of a quantum of ultra-violet light by the carbonyl group have been shown to be similar to those which occur with simple aliphatic ketones; namely, the type I split to form a polymer radical and a free methyl or acetyl radical, and the type II split at the C—C linkage α — β to the carbonyl which results in a decrease in the molecular weight of the polymer and the formation of a double bond. The kinetics of the molecular weight changes have been followed by viscosity, osmotic pressure and ultracentrifuge measurements on the degraded polymers, and it is shown that these can be explained on the basis of a competing reaction which opposes the breakdown by type II. A mechanism is proposed for this reaction which involves a ‘repolymerization’ due to the addition of free radicals to the double bonds formed by type II.

scholarly journals Critical Analysis of Corneal Cross-Linking (Part-II): Resolving the Controversial Issues (Theory Versus Measurements)

2021 ◽  
Author(s):  
Jui-Teng Lin
Keyword(s):  
Light Intensity ◽  
Scaling Laws ◽  
Uv Light ◽  
Corneal Thickness ◽  
Cross Linking ◽  
Type I ◽  
Controversial Issues ◽  
Type Ii ◽  
Stromal Tissue ◽  
Theory Versus

To resolve the controversial issues of UV-light-initiatedcornealcollagen cross-linking (CXL) by theoretical formulas and measured clinical outcomes. The controversial issues are addressed and resolved by analytical formulas including: the validation of Bunsen Roscoe law (BRL), the cutoff light intensity, the minimum corneal thickness, the demarcation line depth, the role of oxygen riboflavin (RF) concentration. The overall CXL efficacy is governed by UV-A light intensity, dose, exposure time, mode of exposure (pulsed or CW), riboflavin concentration, diffusion and drops pre-operation and interoperation administration, concentration of oxygen in the stromal tissue (pre-op and inter-op), and environmental conditions. The length of the riboflavin presoaking time and viscosity of the riboflavin film also affect the crosslink depth. Analytic formulas are derived for the scaling laws for type-I and type-II efficacy, given by the square-root of light intensity, and light dose, respectively. The controversial issues of CXL may be partially resolved via analytic formulas, and compared with measurements. The scaling laws of type-I and type-II efficacy are different and given by analytic formulas. Our formulas also predict the maximum light intensity and the minimum corneal thickness, which are consistent with measurements.

scholarly journals Sec61p is adjacent to nascent type I and type II signal-anchor proteins during their membrane insertion.

1993 ◽  
Vol 121 (4) ◽  
pp. 743-750 ◽  
Author(s):  
S High ◽  
S S Andersen ◽  
D Görlich ◽  
E Hartmann ◽  
S Prehn ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Cross Linking ◽  
Secretory Proteins ◽  
Membrane Insertion ◽  
Type I ◽  
Type Ii ◽  
Core Component ◽  
Signal Anchor ◽  
Membrane Components ◽  
Anchor Proteins

We have identified membrane components which are adjacent to type I and type II signal-anchor proteins during their insertion into the membrane of the ER. Using two different cross-linking approaches a 37-38-kD nonglycosylated protein, previously identified as P37 (High, S., D. Görlich, M. Wiedmann, T. A. Rapoport, and B. Dobberstein. 1991. J. Cell Biol. 113:35-44), was found adjacent to all the membrane inserted nascent chains used in this study. On the basis of immunoprecipitation, this ER protein was shown to be identical to the recently identified mammalian Sec61 protein. Thus, Sec61p is the principal cross-linking partner of both type I and type II signal-anchor proteins during their membrane insertion (this work), and of secretory proteins during their translocation (Görlich, D., S. Prehn, E. Hartmann, K.-U. Kalies, and T. A. Rapoport. 1992. Cell. 71:489-503). We propose that membrane proteins of both orientations, and secretory proteins employ the same ER translocation sites, and that Sec61p is a core component of these sites.

scholarly journals Kinetics of Enhancement for Corneal Cross-linking: Proposed Model for a Two-initiator System

2019 ◽  
pp. 1-6 ◽  
Author(s):  
Jui-Teng Lin
Keyword(s):  
Triplet State ◽  
Rose Bengal ◽  
Singlet State ◽  
Kinetic Equations ◽  
Green Light ◽  
Rate Equations ◽  
Cross Linking ◽  
Type Ii ◽  
Initiator System ◽  
Kinetics Of

Aims: To derive kinetic equations and analytic formulas for efficacy enhancement of corneal collagen crosslinking (CXL) in a 2-initiator system. Study Design:  Modeling the kinetics of CXL. Place and Duration of Study: Taipei, Taiwan, between between January 2019 to June, 2019. Methodology: Coupled rate equations are derived for two initiators system for a type-II process, consisting of a primary initiator (PA), and a co-initiator (PB) as an enhancer, having 3 cross linking pathways: Two radical-mediated (or electron transfer) pathways, and one oxygen-mediated (or energy transfer) pathway. For a type-II process, the triplet state T* interacts with the co-initiator, PB, to form the primary radicals R’, and an active intermediates radical, R, which could interact with the substrate [M] for crosslink, or be inhibited by oxygen [O2], or bimolecular termination. Rate equations, based on lifetime of triplet-state and oxygen singlet-state, are used to analyze the measured results in a rose-Bengal system with an enhanced initiator. Results: Additive enhancer-monomer of arginine added to a rose Bengal photosensitizer may enhance the production of free radicals under a green-light CXL. D2O may extends the lifetime of oxygen singlet state and thus improve the efficacy. Our formulas predicted features are consistent with the measured results. Conclusion: Efficacy may be improved by enhancer-monomer or extended lifetime of photosensitizer triplet-state or oxygen singlet state.

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