Cryptorchidism and spermatic pathway complete dissociation

2021 ◽  
Author(s):  
Javier Arredondo Montero ◽  
Lidia Ayuso González ◽  
Sara Hernández‐Martín ◽  
Mónica Bronte Anaut
Keyword(s):  
Complete Dissociation

Kinetic Studies of [4n+2]π-Thermal Cyclodimerization of 1-(3-Pyridazinyl)-3-oxidopyridinium Betaines

1992 ◽  
Vol 57 (9) ◽  
pp. 1951-1959 ◽  
Author(s):  
Madlene L. Iskander ◽  
Samia A. El-Abbady ◽  
Alyaa A. Shalaby ◽  
Ahmed H. Moustafa
Keyword(s):  
Energy Gap ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Cyclic Transition ◽  
Concerted Mechanism ◽  
First Order ◽  
Thermodynamic Activation Parameters ◽  
Cyclic Transition State ◽  
Complete Dissociation ◽  
Homo Lumo

The reactivity of the base induced cyclodimerization of 1-(6-arylpyridazin-3-yl)-3-oxidopyridinium chlorides in a pericyclic process have been investigated kinetically at λ 380 nm. The reaction was found to be second order with respect to the liberated betaine and zero order with respect to the base. On the other hand dedimerization (monomer formation) was found to be first order. It was shown that dimerization is favoured at low temperature, whereas dedimerization process is favoured at relatively high temperature (ca 70 °C). Solvent effects on the reaction rate have been found to follow the order ethanol > chloroform ≈ 1,2-dichloroethane. Complete dissociation was accomplished only in 1,2-dichloroethane at ca 70 °C. The thermodynamic activation parameters have been calculated by a standard method. Thus, ∆G# has been found to be independent on substituents and solvents. The high negative values of ∆S# supports the cyclic transition state which is in favour with the concerted mechanism. MO calculations using SCF-PPP approximation method indicated low HOMO-LUMO energy gap of the investigated betaines.

Ligand photodissociation in Ru(ii)–1,4,7-triazacyclononane complexes enhances water oxidation and enables electrochemical generation of surface active species

2020 ◽  
Vol 10 (10) ◽  
pp. 3399-3408 ◽  
Author(s):  
Hussein A. Younus ◽  
Nazir Ahmad ◽  
Ibrahim Yildiz ◽  
Serge Zhuiykov ◽  
Shiguo Zhang ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Partial Oxidation ◽  
Water Oxidation ◽  
Active Species ◽  
Electrochemical Generation ◽  
Surface Active ◽  
Complete Dissociation

Ligand transformations involved in metal complexes during water oxidation (WO), such as ligand decomposition, partial oxidation, or complete dissociation have been reported, however, ligand photodissociation has not been reported yet.

scholarly journals Purification and some properties of rabbit antiovalbumin

1973 ◽  
Vol 135 (4) ◽  
pp. 705-711 ◽  
Author(s):  
Aftab A. Ansari ◽  
A. Salahuddin
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Acid Media ◽  
Stokes Radius ◽  
Antigen Antibody ◽  
Two Peaks ◽  
Complete Dissociation ◽  
Phosphate Groups

Unlike previous reports that the ovalbumin–anti-ovalbumin complex did not dissociate completely in acid media, our results showed complete dissociation of the complex both in 1.2m-acetic acid, pH2.3, and in KCl–HCl, pH2.2, I 0.06. Thus Sephadex chromatography of the solution obtained by dissolving the antigen–antibody precipitate in these media repeatedly gave two peaks corresponding to anti-ovalbumin and ovalbumin. Further, gel-diffusion and immunoelectrophoresis experiments showed that the phosphate groups of ovalbumin are not involved in the antigenic sites. The antibody thus purified was more easily precipitated than previous preparations. The molecular weight and Stokes radius of the antibody were calculated from its gel-filtration behaviour and were found to be 148000 and 4.8nm respectively. The molecular weight determined by sodium dodecyl sulphate–polyacrylamide gel electrophoresis was essentially similar (about 0.7% lower).

Anthropological, Social, and Moral Limitations of a Multiplicity of Genders

Hypatia ◽  
2005 ◽  
Vol 20 (2) ◽  
pp. 27-47
Author(s):  
Hilge Landweer ◽  
Gertrude Postl
Keyword(s):  
Theoretical Perspective ◽  
Sex And Gender ◽  
And Gender ◽  
Gender Categories ◽  
Complete Dissociation

This work argues from a social-theoretical perspective for the view that every concept of ‘gender’ remains bound to reproduction. As every culture is interested in its continuity, it distinguishes individuals according to their assumed possible contribution to reproduction and so develops a fundamental dual classification. Subsequent gender categories are necessarily derived from this one. The conceptual and empirical arguments for this thesis are illustrated through an imagined dystopia. There I envision under what conditions a complete dissociation of the concepts ‘sex and ‘gender’ from the old dual distinction would be possible and in what way a multiplicity of genders would be accomplished.

Fabrication and Characterization of RF Plasma Polymerized Thin Films from 3,7-Dimethyl-1,6-octadien-3-ol for Electronic and Biomaterial Applications

2010 ◽  
Vol 123-125 ◽  
pp. 323-326 ◽  
Author(s):  
Kateryna Bazaka ◽  
Mohan V. Jacob ◽  
Robert A. Shanks
Keyword(s):  
Thin Films ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Polymer Chains ◽  
Rf Plasma ◽  
Circuit Boards ◽  
Average Roughness ◽  
Free Surfaces ◽  
Complete Dissociation

Poly(linalool) thin films were fabricated using RF plasma polymerisation. All films were found to be smooth, defect-free surfaces with average roughness of 0.44 nm. The FTIR analysis of the polymer showed a notable reduction in –OH moiety and complete dissociation of C=C unsaturation compared to the monomer, and presence of a ketone band absent from the spectrum of the monomer. Poly(linalool) were characterised by chain branching and a large quantity of short polymer chains. Films were optically transparent, with refractive index and extinction coefficient of 1.55 and 0.001 (at 500 nm) respectively, indicating a potential application as an encapsulating (protective) coating for circuit boards. The optical band gap was calculated to be 2.82 eV, which is in the semiconducting energy gap region.

Cooperativity and regulation through conformational changes as features of phage assembly

1976 ◽  
Vol 276 (943) ◽  
pp. 3-13 ◽  
Keyword(s):  
Experimental Model ◽  
Conformational Changes ◽  
Model Systems ◽  
Conformational States ◽  
Phage Assembly ◽  
Specific Stage ◽  
T4 Phage ◽  
Experimental Model Systems ◽  
Complete Dissociation

The assembly of bacteriophages provides experimental model systems for the study of regulation at the level of gene products. We discuss the hypothesis of regulation through sequentially induced conformational changes by which precursor-assemblies become ready at a specific stage of maturation to interact with an additional gene product or nucleic acids. Phage mutants provide excellent experimental model systems for studying, for example, the role and fate of the core in the prehead assembly. The conservative maturation of the prehead to the final, stable head consists of several steps whose complexity reflect that of the virus. It includes packaging of DNA. The surface lattice of maturing preheads apparently undergoes several steps characterized by different conformational states as suggested by in vitro studies on a morphological variant of the prehead, the polyhead of phage T4 (Steven, Couture, Aebi & Showe 1976; Laemmli, Amos & Klug 1976). Addition of a partly purified, enriched proteolytic fraction - which is gene 21-dependent - to empty purified polyheads leads to different conformational states. These seem to go in a direction approaching the structure of the surface of finished capsids as studied by Aebi et al . on gene 24 related (Bijlenga, Aebi & Kellenberger 1976) and other genetically defined giant-variants of T4 phage (Doermann, Eiserling & Boehner 1973). We show some experiments which suggest that high cooperativity is responsible for the stabilization of capsids. The activation energy necessary for dissociation of capsids is very high, 247 kJ for T4 capsids, and 10% smaller for T2. Once the energy barrier has been overcome, the capsids are first structurally modified before they undergo partial and finally complete dissociation.

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