An introduction to biominerals and the role of organic molecules in their formation

1984 ◽  
Vol 304 (1121) ◽  
pp. 411-424 ◽  
Keyword(s):  
Organic Molecules ◽  
Organic Materials ◽  
Solubility Limit ◽  
Nucleation And Growth ◽  
The Other ◽  
Medical Problems ◽  
Calcium Compounds ◽  
Inorganic Components ◽  
Iron And Calcium

The minerals of biology have two components, one of which is inorganic and the other organic. Understanding rests initially in the description of the factors that control the nucleation and growth of the inorganic components in the absence of organic materials, and in the study of the organic materials in the absence of the inorganic phase. Brief summaries of these studies are given and then an attempt is made to examine some of the interactive features of the whole mineral. There are very few generalizations that can be formulated yet since each mineral appears to be associated with the metabolic processes of a special cell. Partly, this is due to the diverse function that biominerals perform: supports, protection, sensors, storage and even homeostasis. We must also be aware of the vulnerable nature of precipitation control above the solubility limit. Many widespread medical problems involve the incorrect precipitation of iron and calcium compounds especially.

scholarly journals The Influence of Silica Nanoparticles Geometry on the Interfacial Interactions of Organic Molecules: A Simulation Perspective

2022 ◽  
Author(s):  
Prasad Rama ◽  
Zareen Abbas
Keyword(s):  
Silica Nanoparticles ◽  
Organic Molecules ◽  
Particle Surface ◽  
The Other ◽  
Interfacial Interactions ◽  
Nanoparticle Shape ◽  
Other Hand ◽  
Adsorption Of Organic Molecules ◽  
Unexplored Area

The role of nanoparticle shape in the interaction and adsorption of organic molecules on the particle surface is an unexplored area. On the other hand, such knowledge is not only...

scholarly journals Attitudes Toward Menopause

1993 ◽  
Vol 17 (3) ◽  
pp. 275-288 ◽  
Author(s):  
Linda Gannon ◽  
Bonnie Ekstrom
Keyword(s):  
Potential Role ◽  
Life Transitions ◽  
The Other ◽  
Medical Problems ◽  
Medical Context ◽  
Positive Attitudes ◽  
And Behavior ◽  
The Impact

This research examined the influence of sociocultural paradigms of menopause on attitudes toward menopause. Five hundred eighty-one women and men, between the ages of 18 and 85, were assigned to one of three groups distinguished by the context within which they expressed their attitudes toward menopause. The contexts were designed to reflect particular paradigms: one group described their attitudes toward three medical problems, including menopause; a second group described their attitudes toward three life transitions, including menopause; and a third group described their attitudes toward three symbols of aging, including menopause. Positive and negative subscales of the attitude questionnaires for menopause were analyzed for context and age/experience. Results indicated that the medical context elicited significantly more negative and fewer positive attitudes than did the other two contexts, particularly among older participants. In general, women's attitudes were more positive than were men's, and attitudes became increasingly positive with age and/or experience. The discussion includes the potential role of attitudes as mediating the impact of sociocultural paradigms on experience and behavior.

scholarly journals Excited State Mechanisms in Crystalline Carbazole: The Role of Aggregation and Isomeric Defects

2021 ◽  
Author(s):  
Federico J. Hernández ◽  
Rachel Crespo Otero
Keyword(s):  
Experimental Study ◽  
Excited State ◽  
Room Temperature ◽  
Organic Molecules ◽  
Organic Materials ◽  
State Of The Art ◽  
Computational Approaches ◽  
Recent Experimental Study ◽  
Phosphorescence At Room Temperature

The molecule of Carbazole (Cz) is commonly used as a building block in organic materials for optoelectronic applications, acting as light-absorbing, electron donor and emitting moiety. Crystals from Cz and derivatives display ultralong phosphorescence at room temperature. However, different groups have reported inconsistent quantum efficiencies for the same compounds. In a recent experimental study by Liu et al. (<i>Nature Materials</i> <b>2021</b>, 20, 175-180), the ultralong phosphoresce properties of Cz have been associated with the presence of small fractions of isomeric impurities from commercially available Cz. In this paper, we use state-of-the-art computational approaches to investigate light-induced processes in crystalline and doped Cz. We revisit the role of aggregation and isomeric impurities on the excited state pathways and analyse the mechanisms for exciton, Dexter energy transfer and electron transport based on Marcus and Marcus-Levich-Jortner theories. Our excited state mechanisms provide a plausible interpretation for the experimental results and support the formation of charge-separated states at the defect/Cz molecular interface. These results contribute to a better understanding of the factors enhancing the excited state lifetimes in organic materials and the role of doping with organic molecules.

scholarly journals Effect of Biochar on the Production of L-Histidine From Glucose Through Escherichia coli Metabolism

2021 ◽  
Vol 8 ◽  
Author(s):  
Yang E ◽  
Jun Meng ◽  
Heqing Cai ◽  
Caibin Li ◽  
Sainan Liu ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Traditional Method ◽  
Organic Molecules ◽  
Lethal Dose ◽  
The Other ◽  
Related Gene ◽  
High Concentration ◽  
E Coli ◽  
Hormone Analogs

The organic compounds from biochar play a role of hormone analogs, stimulating the expression of metabolites by controlling related gene and protein. In this experiment, we reported the L-histidine biosysthesis was promoted by biochar treatment in E. coli unlike genetic engineering of the traditional method. The related results indicated the most optimal concentration was found to be 3%, and 7% is the lethal dose. E. coli was inhibited in the high-concentration treatment. On the other hand, docking technology was usually used as drug screening, basing on Lock-and-key model of protein in order to better understand mechanisms. So the organic compounds of biochar from GC-MS analysis that acted as ligands were connected to HisG protein controlling L-histidine biosysthesis in E. coli. The result showed that the three organic molecules interacted with HisG protein by hydrogen bond. So we considered that these three compounds play regulatory roles in L-histidine biosysthesis, and the hisG gene expression fully supports this conclusion.

scholarly journals Excited State Mechanisms in Crystalline Carbazole: The Role of Aggregation and Isomeric Defects

2021 ◽  
Author(s):  
Federico J. Hernández ◽  
Rachel Crespo Otero
Keyword(s):  
Experimental Study ◽  
Excited State ◽  
Room Temperature ◽  
Organic Molecules ◽  
Organic Materials ◽  
State Of The Art ◽  
Computational Approaches ◽  
Recent Experimental Study ◽  
Phosphorescence At Room Temperature

The molecule of Carbazole (Cz) is commonly used as a building block in organic materials for optoelectronic applications, acting as light-absorbing, electron donor and emitting moiety. Crystals from Cz and derivatives display ultralong phosphorescence at room temperature. However, different groups have reported inconsistent quantum efficiencies for the same compounds. In a recent experimental study by Liu et al. (<i>Nature Materials</i> <b>2021</b>, 20, 175-180), the ultralong phosphoresce properties of Cz have been associated with the presence of small fractions of isomeric impurities from commercially available Cz. In this paper, we use state-of-the-art computational approaches to investigate light-induced processes in crystalline and doped Cz. We revisit the role of aggregation and isomeric impurities on the excited state pathways and analyse the mechanisms for exciton, Dexter energy transfer and electron transport based on Marcus and Marcus-Levich-Jortner theories. Our excited state mechanisms provide a plausible interpretation for the experimental results and support the formation of charge-separated states at the defect/Cz molecular interface. These results contribute to a better understanding of the factors enhancing the excited state lifetimes in organic materials and the role of doping with organic molecules.

Plasma Levels of Protein S, Protein C, and Factor X: Effects of Sex, Hormonal State and Age

1995 ◽  
Vol 74 (05) ◽  
pp. 1271-1275 ◽  
Author(s):  
C M A Henkens ◽  
V J J Bom ◽  
W van der Schaaf ◽  
P M Pelsma ◽  
C Th Smit Sibinga ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Postmenopausal Women ◽  
Protein C ◽  
Blood Donors ◽  
Premenopausal Women ◽  
Protein S ◽  
The Other ◽  
Factor X ◽  
Normal Ranges

SummaryWe measured total and free protein S (PS), protein C (PC) and factor X (FX) in 393 healthy blood donors to assess differences in relation to sex, hormonal state and age. All measured proteins were lower in women as compared to men, as were levels in premenopausal women as compared to postmenopausal women. Multiple regression analysis showed that both age and subgroup (men, pre- and postmenopausal women) were of significance for the levels of total and free PS and PC, the subgroup effect being caused by the differences between the premenopausal women and the other groups. This indicates a role of sex-hormones, most likely estrogens, in the regulation of levels of pro- and anticoagulant factors under physiologic conditions. These differences should be taken into account in daily clinical practice and may necessitate different normal ranges for men, pre- and postmenopausal women.

On the role of the dispute between "non-possessors" and "Josephites" in the culture of Moscow's prediction

1998 ◽  
pp. 61-62
Author(s):  
N. S. Jurtueva
Keyword(s):  
The Other ◽  
Moral Transformation ◽  
15Th Century ◽  
The Future ◽  
Secular Power

In the XIV century. centripetal tendencies began to appear in the Moscow principality. Inside the Russian church, several areas were distinguished. Part of the clergy supported the specificobar form. The other understood the need for transformations in society. As a result, this led to a split in the Russian church in the 15th century for "non-possessors" and "Josephites". The former linked the fate of the future with the ideology of hesychasm and its moral transformation, while the latter sought support in alliance with a strong secular power.

From Container to Claustrum: Projective Identification in Couples

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman
Keyword(s):  
Psychological Health ◽  
Projective Identification ◽  
The Self ◽  
The Other ◽  
Intimate Partners ◽  
And Control ◽  
The Relationship ◽  
As If

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.

Thomas More's “rule” of pleasure before, after, and inUtopia

Moreana ◽  
2017 ◽  
Vol 54 (Number 207) (1) ◽  
pp. 36-56
Author(s):  
Gerard Wegemer
Keyword(s):  
Human Nature ◽  
The Other ◽  
Biblical Allusions ◽  
De Officiis

After establishing a context of More's lifelong engagement with the “calculus” of pleasure, this essay shows how the section devoted to the Utopians' pleasure philosophy is structured around five formulations of a “rule” to calculate “true and honest [honesta]” pleasure in ways that playfully imitate and echo the “rule” Cicero formulates several times in De officiis to discern one's duty when there seems to be a conflict between honestas et utilitas. When followed, the Utopian pleasure calculus shows the necessary role of societas, officii, iustitia, caritas, and the other aspects of human nature, most importantly friendship, that Cicero stresses in his rule and that he argued Epicurus ignored. Much of the irony and humor of this section depends on seeing the predominance of Ciceronian vocabulary in Raphael's unusual defense [patrocinium] of pleasure, rather than a Ciceronian defense of duty rooted in honestas. Throughout, however, this essay also shows how More goes beyond Cicero by including Augustinian and biblical allusions to suggest ways that our final end is not as Epicurus or the Stoics or Cicero claim; the language and allusions of this section point to a level of good cheer and care for neighbors and for God in ways quite different from any classical thinker.

BLOCKADE OF THE SURGE OF PROLACTIN AT PRO-OESTRUS BY ADMINISTRATION OF ANTI-OESTROGENIC SUBSTANCE, MER-25

1973 ◽  
Vol 74 (4) ◽  
pp. 769-774 ◽  
Author(s):  
Akira Yokoyama ◽  
Hiroshi Tomogane ◽  
Katuaki Ôta
Keyword(s):  
Strong Evidence ◽  
The Other ◽  
Other Hand

ABSTRACT A non-steroidal oestrogen antagonist, MER-25, was administered to cycling rats for elucidating the role of oestrogen in the surge of prolactin observed on the afternoon of pro-oestrus (POe). In animals injected with 20 mg of MER-25 intramuscularly on the afternoon (16.30 h) of the first day of dioestrus (D-1), the surge of prolactin was blocked while the level of prolactin on the afternoon of POe of these animals was significantly higher than that of the corresponding controls injected with oil. Ovulation was also blocked in these animals treated with the drug on the afternoon of D-l. On the other hand, treatment on the morning (10.30 h) of the 2nd day of dioestrus failed to prevent not only the surge of prolactin but also ovulation. These observations provide strong evidence for the view that oestrogen is responsible for the surge of prolactin on the afternoon of POe, and that the surge is accompanied by that of LH.

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