scholarly journals Development of Functional Models for a SOD

2002 ◽  
Vol 9 (1-2) ◽  
pp. 9-18 ◽  
Author(s):  
Ali Arslantas
Keyword(s):  
Model Compound ◽  
Active Oxygen Species ◽  
Active Species ◽  
Phagocytic Cells ◽  
Model Compounds ◽  
Protective Mechanisms ◽  
Sod Activity ◽  
Functional Models ◽  
Electron Transport Chains ◽  
The Relationship

Superoxide dismutase (SOD) is the scavenger of superoxide anion (O2−) and functions as a protector of living bodies. Study of a model compound of SOD is important when searching for the relationship between functions and structures of enzymes. Furthermore, SOD model compounds have potential for therapeutic usefulness. Although many SOD: model compounds have been reported, their structures are quite different from those of the native enzyme. Cu,Zn-SOD has been proposed for clinical uses. Unfortunately, many problems such as half-lifetime and antigenicity have not been overcome even though several copper(II) complexes are known to show SOD activity. Active oxygen species such as superoxide (O2−) from various components of the cellular electron transport chains, and provided during the respiratory burst of phagocytic cells, have been implicated both in the aging process and in degenerative diseases, including arthritis and cancer. Therefore, the biological system posseses the protective mechanisms against active species.

scholarly journals The structure of heparin oligosaccharide fragments with high anti-(factor Xa) activity containing the minimal antithrombin III-binding sequence Chemical and13C nuclear-magnetic-resonance studies

1981 ◽  
Vol 197 (3) ◽  
pp. 599-609 ◽  
Author(s):  
B Casu ◽  
P Oreste ◽  
G Torri ◽  
G Zoppetti ◽  
J Choay ◽  
...  
Keyword(s):  
Uronic Acid ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Amino Sugar ◽  
Active Species ◽  
Model Compounds ◽  
High Affinity ◽  
The Common ◽  
Binding Sequence ◽  
Heparin Oligosaccharides

The chemical composition and the 13C n.m.r. spectra of heparin oligosaccharides (essentially octasaccharides), having high affinity for antithrombin III and high anti-(Factor Xa) activity, prepared by three independent approaches (extraction, partial deaminative cleavage with HNO2 and partial depolymerization with bacterial heparinase), leading to different terminal residues, have been studied and compared with those of the corresponding inactive species. Combined wit chemical data, the spectra of the active oligosaccharides and of their fragmentation products afforded information on composition and sequence. The three types of active oligosaccharides were shown to have the common hexasaccharide core I-Aa-G-As*-Is-As, where I and alpha-L-idopyranosyl-uronic acid, Aa = 2-acetamido-2-deoxy-alpha-D-glucopyranose, G = beta-D-glucopyranosyl-uronic acid, Is = alpha-L-idopyranosyluronic acid 2-O-sulphate, As = 2-deoxy-2-sulphamino-alpha-D-glucopyranose 6-O-sulphate. The fourth residue (As*) is an unusually substituted amino sugar resistant to mild deamination. The 13C spectra of the active species are characterized by signals from the above atypical amino sugar, the most evident of which is at 57.7 p.p.m. These signals, compared with those of appropriate synthetic model compounds, are compatible with the recently proposed 3-O-sulphation of the residue As* [Lindahl, Bäckström, Thunberg & Leder (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 6551-6555].

Some Ontological Distinctions of Function Based on the Role Concept

2009 ◽  
Author(s):  
Yoshinobu Kitamura ◽  
Riichiro Mizoguchi
Keyword(s):  
Life Cycle ◽  
Engineering Design ◽  
Product Life Cycle ◽  
Functional Modeling ◽  
Ontological Engineering ◽  
Product Life ◽  
Functional Models ◽  
Role Concept ◽  
Essential Function ◽  
The Relationship

Function is an important aspect of artifacts in engineering design. Although many definitions of function have been proposed in the extensive research mainly in engineering design and philosophy, the relationship among them remains unclear. Aiming at a contribution to this problem, this paper investigates some ontological issues based on the role concept in ontological engineering. We discuss some ontological distinctions of function such as essentiality and actuality and then propose some fundamental kinds of function such as essential function and capacity function. Based on them, we categorize some existing definitions in the literature and clarify the relationship among them. Then, a model of function in a product life-cycle is proposed. It represents the changes of existence of the individuals of each kind of function, which are caused by designing, manufacturing and use. That model enables us to give answers to some ontological questions such as when and where a function exists and what a function depends on. The consideration on these issues provides engineers with some differentiated viewpoints for capturing functions and thus contributes to consistent functional modeling from a specific viewpoint. The clarified relationships among the kinds of function including the existing definitions in the literature will contribute to interoperability among functional models based on the different kinds and/or definitions.

scholarly journals Capital Structure-Firm Value Nexus: Moderating Role of Profitability

2020 ◽  
Vol 11 (2) ◽  
pp. 375-386
Author(s):  
Hamed Ahmad Almahadin ◽  
Yazan Salameh Oroud
Keyword(s):  
Capital Structure ◽  
Firm Value ◽  
Panel Data Analysis ◽  
Policy Implications ◽  
Ample Evidence ◽  
Functional Models ◽  
The Impact ◽  
The Relationship ◽  
Moderating Role

This study aims to investigate the moderating role of profitability in the relationship between capital structure and firm value in Jordan, as an example of an emerging economy. For this purpose, two functional models were formulated to capture the direct relationship as well as the interaction impact of capital structure on firm value. The robust empirical findings of panel data analysis provide strong evidence of an adverse relationship between capital structure and firm value. The findings confirm that the impact of capital structure appears to be complicated in nature and difficult to examine without controlling for the interaction of profitability as one of the major determinants. Therefore, studying the interaction effect provides ample evidence and enhances the understanding of the link between firm value and capital structure. The empirical results of the study may provide important insights and policy implications to decision-makers.

scholarly journals Acid phosphatase activity in mononuclear phagocytes and the U937 cell line: monocyte-derived macrophages express tartrate-resistant acid phosphatase

Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 729-734
Author(s):  
RG Snipes ◽  
KW Lam ◽  
RC Dodd ◽  
TK Gray ◽  
MS Cohen
Keyword(s):  
Acid Phosphatase ◽  
Cell Line ◽  
Gel Electrophoresis ◽  
U937 Cell ◽  
Colorimetric Assay ◽  
Mononuclear Phagocytes ◽  
Tartrate Resistant Acid Phosphatase ◽  
U937 Cells ◽  
Phagocytic Cells ◽  
The Relationship

Tartrate-resistant acid phosphatase (TRAcP) is used as a marker for osteoclasts, which are believed to be derived from phagocytic cells or phagocyte stem cell precursors. To further investigate the relationship between monocytic phagocytes and osteoclasts, acid phosphatase (AcP) activity was measured by three different techniques in human peripheral blood monocytes, monocyte-derived macrophages, and the U937 cell line. We found that cytochemistry and gel electrophoresis led to similar results, but that the colorimetric assay was inconsistent. Normal human peripheral monocytes expressed both tartrate-sensitive and -resistant AcP. In culture these cells formed polykaryons and expressed TRAcP activity that was further identified as an isoenzyme associated with bone tissue. In contrast, the U937 cells did not express TRAcP activity as measured by gel electrophoresis. Both U937 cells and monocytes possess material that interferes with interpretation of the colorimetric assay of AcP. The presence of TRAcP in monocyte-derived macrophages further supports the relationship between phagocytic cells and bone osteoclasts.

Halogenation of Butyl Rubber—A Model Compound Approach

1984 ◽  
Vol 57 (2) ◽  
pp. 275-283 ◽  
Author(s):  
R. Vukov
Keyword(s):  
Model Compound ◽  
Product Distribution ◽  
Butyl Rubber ◽  
Methyl Groups ◽  
Reaction Site ◽  
Model Compounds ◽  
Reaction Conditions ◽  
Basic Study ◽  
Rubber Model ◽  
Trisubstituted Alkenes

Abstract The study of the halogenation behavior of butyl rubber model compounds has brought about a better understanding of the behavior of these systems. It has been established that the presence of methyl groups, in a position B to the reaction site in the butyl rubber model compound, profoundly influences the course of halogenation. Due to the steric hindrance imposed by these groups, both the products of chlorination and bromination deviate from patterns typical of other trisubstituted alkenes. In the case of chlorination, this deviation is demonstrated by the absence of addition products of chlorine across the double bond. In the case of bromination reactions, the change in product distribution is even more dramatic. Thus, substitution products normally not observed in bromination reactions of other trisubstituted alkenes become predominant products found in yields of between 70–90% depending on the precise reaction conditions. The behavior of the butyl model compound appears to be entirely consistent with the behavior of butyl rubber itself; the model compound approach is therefore a valuable tool for use in the basic study of this type of system.

scholarly journals TNFα Mediates the Interaction of Telomeres and Mitochondria Induced by Hyperglycemia: A Rural Community-Based Cross-Sectional Study

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Lu Lyu ◽  
Shuli He ◽  
Huabing Zhang ◽  
Wei Li ◽  
Jingbo Zeng ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Glucose Tolerance ◽  
Rural Community ◽  
Rural China ◽  
Inflammatory Factors ◽  
Oral Glucose ◽  
Sod Activity ◽  
Cross Sectional ◽  
Mitochondrial Dna Copy Number ◽  
The Relationship

This study is aimed at evaluating the relationship between leukocyte telomere length (LTL) and mitochondrial DNA copy number (mtDNAcn) in a noninterventional rural community of China with different glucose tolerance statuses. In addition, we investigate whether the indicators of oxidative stress and inflammation were involved and identify mediators among them. A total of 450 subjects in rural China were included and divided into two groups according to a 75 g oral glucose tolerance test (OGTT): the abnormal glucose metabolism (AGM, n=257, 57.1%) group and the normal glucose tolerance (NGT, n=193, 42.9%) group. Indicators of oxidative stress (superoxide dismutase (SOD) and glutathione reductase (GR)) and inflammatory indices (tumor necrosis factor α (TNFα) and interleukin-6 (IL-6)) were all determined by ELISA. LTL and mtDNAcn were measured using a real-time PCR assay. Linear regressions were used to adjust for covariates that might affect the relationship between LTL and mtDNAcn. Mediation analyses were utilized to evaluate the mediators. In the AGM, LTL was correlated with mtDNAcn (r=0.214, p=0.001), but no correlation was found in the NGT. The association between LTL and mtDNAcn was weakened after adjusting for inflammatory factors in the AGM (p=0.087). LTL and mtDNAcn were both inversely related to HbA1c, IL-6, TNFα, and SOD activity. Mediation analysis demonstrated that TNFα was a significant mediator in the telomere-mitochondrial interactome in the AGM. This result suggests that inflammation and oxidative stress may play a vital role in telomere shortening as well as mitochondrial dysfunction. In the subjects with hyperglycemia, a significant positive correlation is observed between LTL and mtDNAcn, which is probably mediated by TNFα. TNFα may be considered a potential therapeutic target against aging-related disease in hyperglycemia.

Structure rétinienne et la Vascularisation intraoculaire chez quelques poissons marins de la région de Gaspé

1968 ◽  
Vol 46 (4) ◽  
pp. 729-745 ◽  
Author(s):  
M. A. Ali ◽  
M. Anctil ◽  
H. M. Mohideen
Keyword(s):  
Blood Supply ◽  
Active Species ◽  
The Third ◽  
Retinal Structure ◽  
Second Category ◽  
The Relationship

Twenty-five species belonging to 12 families were studied. Their habitats ranged from coastal, pelagic zones to depths of about 300 meters. Corresponding variations in retinal structure, intraocular circulation, and activity were observed. Based on these, three categories have been established. The first includes species with poorly developed retinae, very sparse circulation, and no activity, inhabiting deeper waters; the third comprises active species with well-developed retinae and good blood supply, inhabiting coastal or pelagic zones. The second category groups the intermediate forms. Variations in retinal structure and circulation and the relationship between the two aspects are discussed.

Convenient preparation of a β-O-4-type lignin model trimer via KOH-catalyzed hydroxymethylation and a new protection method

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Maarit Lahtinen ◽  
Anssi Haikarainen ◽  
Jussi Sipilä
Keyword(s):  
Model Compound ◽  
Catalytic Amount ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Chemical Behavior ◽  
Model Compounds ◽  
Protection Method ◽  
Convenient Synthesis ◽  
Lignin Model ◽  
Convenient Preparation

Abstract Lignin, as the second most abundant biopolymer on earth, is one of the targets for plant biorefinery studies. Its complex chemical behavior is frequently studied by dimeric, trimeric, etc. model compounds, preferably with a β-O-4-type structure. In the present study, a convenient synthesis of a β-O-4-type trimeric model compound possessing a free syringylic hydroxyl has been investigated. Two key modifications were in focus: (1) Protection of the aliphatic hydroxyl groups of the starting phenolic dimer prior to the SN2 displacement reaction before introducing the syringylic moiety with 2,2-dimethoxypropane. (2) The hydroxymethylation step to introduce the full side chain moiety. When this reaction was performed in dioxane/water in the presence of a catalytic amount of KOH instead of K2CO3, the formation of a side product via dehydration was markedly reduced. In addition, a convenient method for introducing an α,β-epoxide structure in acetophenone is recommended.

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