scholarly journals Synthesis and analytical characterization of all N–N-coupled, dimeric oxidation products of α-tocopheramine: hydrazo-, azo-, and azoxy-tocopherol

2021 ◽  
Vol 152 (10) ◽  
pp. 1231-1239
Author(s):  
Anjan Patel ◽  
Thomas Rosenau
Keyword(s):  
Aqueous Media ◽  
Analytical Data ◽  
Oxidation Products ◽  
Reaction Systems ◽  
Unknown Structure ◽  
Dimerization Product ◽  
The Common ◽  
First Time ◽  
By Products

AbstractTocopherols are a mixture of antioxidants which are commonly referred to as vitamin E. Tocopheramines differ from tocopherols by an amino function in lieu of the phenolic OH group. They are potent antioxidants which are used in biomedical scenarios as well as stabilizers for polymers against aging. While in aqueous media α-tocopheramine is mainly oxidized to α-tocopherylquinone and N-oxidized by-products, oxidation in apolar media or in polymeric matrices mainly leads to dimeric compounds of hitherto unknown structure. In the present study, we synthesized the whole array of N,N-dimerization product of α-tocopheramine, including the hydrazo, azo, and azoxy derivatives for the first time, and provided comprehensive analytical data as well as general protocols to access the compounds in straightforward syntheses. These results can now be used to identify the common oxidation by-products of α -tocopheramine in different reaction systems. Graphic abstract

scholarly journals Synthesis and analytical characterization of monomeric N-oxidized derivatives of α-tocopheramine

2021 ◽  
Author(s):  
Anjan Patel ◽  
Andreas Hofinger ◽  
Thomas Rosenau
Keyword(s):  
Aqueous Media ◽  
Analytical Data ◽  
Nitro Derivative ◽  
Oxidation Products ◽  
Natural Polymers ◽  
Analytical Characterization ◽  
Derivatives Of ◽  
Synthetic And Natural Polymers

Abstractα-Tocopheramine has shown great promises as a stabilizer for synthetic and natural polymers, but is also investigated in various biomedical scenarios. Many studies have been hampered by the fact that the oxidation products of α-tocopheramine have not yet been properly identified and their analytical data are still lacking. In the present study, we synthesized and fully analytically characterized all N-oxidation products that can form upon oxidation of α-tocopheramine in aqueous media, including the hydroxylamine, nitroso, and nitro derivative, in this way providing standards for the identification of the so far elusive byproducts. Synthesis and stability of the derivatives are discussed. Graphic abstract

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

scholarly journals Extraction and Mass Spectrometric Characterization of Terpenes Recovered from Olive Leaves Using a New Adsorbent-Assisted Supercritical CO2 Process

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1301
Author(s):  
Zully J. Suárez Montenegro ◽  
Gerardo Álvarez-Rivera ◽  
Jose A. Mendiola ◽  
Elena Ibáñez ◽  
Alejandro Cifuentes
Keyword(s):  
Aluminum Oxide ◽  
Silica Gel ◽  
Supercritical Co2 ◽  
Olive Leaves ◽  
Fractionation Process ◽  
Selective Enrichment ◽  
Adsorption Desorption ◽  
First Time ◽  
By Products

This work reports the use of GC-QTOF-MS to obtain a deep characterization of terpenoid compounds recovered from olive leaves, which is one of the largest by-products generated by the olive oil industry. This work includes an innovative supercritical CO2 fractionation process based on the online coupling of supercritical fluid extraction (SFE) and dynamic adsorption/desorption for the selective enrichment of terpenoids in the different olive leaves extracts. The selectivity of different commercial adsorbents such as silica gel, zeolite, and aluminum oxide was evaluated toward the different terpene families present in olive leaves. Operating at 30 MPa and 60 °C, an adsorbent-assisted fractionation was carried out every 20 min for a total time of 120 min. For the first time, GC-QTOF-MS allowed the identification of 40 terpenoids in olive leaves. The GC-QTOF-MS results indicate that silica gel is a suitable adsorbent to partially retain polyunsaturated C10 and C15 terpenes. In addition, aluminum oxide increases C20 recoveries, whereas crystalline zeolites favor C30 terpenes recoveries. The different healthy properties that have been described for terpenoids makes the current SFE-GC-QTOF-MS process especially interesting and suitable for their revalorization.

scholarly journals Genetic characterization at the species and symbiovar level of indigenous rhizobial isolates nodulating Phaseolus vulgaris in Greece

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evdoxia Efstathiadou ◽  
Georgia Ntatsi ◽  
Dimitrios Savvas ◽  
Anastasia P. Tampakaki
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Phylogenetic Affiliation ◽  
Rhizobial Inoculation ◽  
Rhizobial Species ◽  
The Common ◽  
First Time ◽  
Of Greece ◽  
Rhizobial Isolates

AbstractPhaseolus vulgaris (L.), commonly known as bean or common bean, is considered a promiscuous legume host since it forms nodules with diverse rhizobial species and symbiovars. Most of the common bean nodulating rhizobia are mainly affiliated to the genus Rhizobium, though strains belonging to Ensifer, Pararhizobium, Mesorhizobium, Bradyrhizobium, and Burkholderia have also been reported. This is the first report on the characterization of bean-nodulating rhizobia at the species and symbiovar level in Greece. The goals of this research were to isolate and characterize rhizobia nodulating local common bean genotypes grown in five different edaphoclimatic regions of Greece with no rhizobial inoculation history. The genetic diversity of the rhizobial isolates was assessed by BOX-PCR and the phylogenetic affiliation was assessed by multilocus sequence analysis (MLSA) of housekeeping and symbiosis-related genes. A total of fifty fast-growing rhizobial strains were isolated and representative isolates with distinct BOX-PCR fingerpriniting patterns were subjected to phylogenetic analysis. The strains were closely related to R. anhuiense, R. azibense, R. hidalgonense, R. sophoriradicis, and to a putative new genospecies which is provisionally named as Rhizobium sp. I. Most strains belonged to symbiovar phaseoli carrying the α-, γ-a and γ-b alleles of nodC gene, while some of them belonged to symbiovar gallicum. To the best of our knowledge, it is the first time that strains assigned to R. sophoriradicis and harbored the γ-b allele were found in European soils. All strains were able to re-nodulate their original host, indicating that they are true microsymbionts of common bean.

scholarly journals Bakerian lecture - Amino-acid analysis and the structure of proteins

1942 ◽  
Vol 131 (863) ◽  
pp. 136-160 ◽  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Nutritive Value ◽  
Analytical Data ◽  
Seed Proteins ◽  
Decomposition Products ◽  
First Time ◽  
Structure Of Proteins

In recent years the X-ray crystallographers have made remarkable advances in the interpretation of protein structure, and it is becoming more and more evident that a stage has been reached when their views need to be reconciled with data obtained from accurate amino-acid analysis of the proteins concerned. In all too many cases these data are, unfortunately, not yet available, and the reason why the analyst cannot supply them at short notice is due not so much to the com­plexity of the problem—which he has never sought to minimize—but to the fact that many of the more important methods of analysis in current use are an inheritance from an earlier period when such accuracy as is now demanded would have been considered almost impossible of achievement. From about 1840 until 1900, following the lead given by Liebig and later by Ritthausen, the attention of protein chemists was centred chiefly on the prepara­tion and characterization of various animal and seed proteins; as substances of physiological interest their enzymic digestion products were studied in elaborate detail by Kühne, but little attention was paid to the ultimate decomposition products, the amino-acids, in spite of the fact that Ritthausen as early as 1872 had pointed out that the proportions in which these occur might be characteristic of the protein concerned. The enunciation by Hofmeister and Fischer of the peptide hypothesis in 1901 emphasized for the first time the fundamental importance of the amino-acids, and a most fruitful period followed in which attention became almost exclusively focused on these products. Under the inspiring leadership of Fischer himself great improvements were effected in the separation and identification of the amino-acids, so that by about 1915 reasonably good analyses were available for most of the better-known proteins. Though far from complete, the analytical data showed quite clearly that proteins could differ widely in composition, and in many cases it was possible to correlate composition with nutritive value. Such an aim was, indeed, the incentive behind much of the work of this period.

scholarly journals Degradation of 2,4,6-Trichlorophenol by Phanerochaete chrysosporium: Involvement of Reductive Dechlorination

1998 ◽  
Vol 180 (19) ◽  
pp. 5159-5164 ◽  
Author(s):  
G. Vijay Bhasker Reddy ◽  
Maarten D. Sollewijn Gelpke ◽  
Michael H. Gold
Keyword(s):  
Phanerochaete Chrysosporium ◽  
Reductive Dechlorination ◽  
Oxidation Products ◽  
Ring Cleavage ◽  
Fungal Metabolites ◽  
Subsequent Degradation ◽  
Metabolic Conditions ◽  
The Common ◽  
Dechlorination Reaction

ABSTRACT Under secondary metabolic conditions, the lignin-degrading basidiomycete Phanerochaete chrysosporium mineralizes 2,4,6-trichlorophenol. The pathway for the degradation of 2,4,6-trichlorophenol has been elucidated by the characterization of fungal metabolites and oxidation products generated by purified lignin peroxidase (LiP) and manganese peroxidase (MnP). The multistep pathway is initiated by a LiP- or MnP-catalyzed oxidative dechlorination reaction to produce 2,6-dichloro-1,4-benzoquinone. The quinone is reduced to 2,6-dichloro-1,4-dihydroxybenzene, which is reductively dechlorinated to yield 2-chloro-1,4-dihydroxybenzene. The latter is degraded further by one of two parallel pathways: it either undergoes further reductive dechlorination to yield 1,4-hydroquinone, which isortho-hydroxylated to produce 1,2,4-trihydroxybenzene, or is hydroxylated to yield 5-chloro-1,2,4-trihydroxybenzene, which is reductively dechlorinated to produce the common key metabolite 1,2,4-trihydroxybenzene. Presumably, the latter is ring cleaved with subsequent degradation to CO2. In this pathway, the chlorine at C-4 is oxidatively dechlorinated, whereas the other chlorines are removed by a reductive process in which chlorine is replaced by hydrogen. Apparently, all three chlorine atoms are removed prior to ring cleavage. To our knowledge, this is the first reported example of aromatic reductive dechlorination by a eukaryote.

Quadrol-Pd(II) complexes: phosphine-free precatalysts for the room-temperature Suzuki-Miyaura synthesis of nucleoside analogues in aqueous media

2022 ◽  
Author(s):  
Jose Luis Serrano ◽  
Sujeet Gaware ◽  
Jose Antonio Pérez de Haro ◽  
Jose Pérez ◽  
Pedro Lozano ◽  
...  
Keyword(s):  
Room Temperature ◽  
Aqueous Media ◽  
Water Soluble ◽  
Nucleoside Analogues ◽  
Synthesis And Characterization ◽  
First Time

Commercially available Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (THPEN), has been used for the first time as N^N- donor neutral hydrophilic ligand in the synthesis and characterization of new water soluble palladium (II) complexes...

scholarly journals Histological and histochemical characterization of the secretory cells of Choeradoplana iheringi Graff, 1899 (Platyhelminthes: Tricladida: Terricola)

2004 ◽  
Vol 64 (3a) ◽  
pp. 511-522 ◽  
Author(s):  
S. A. de Souza ◽  
A. M. Leal-Zanchet
Keyword(s):  
Secretory Cell ◽  
Basic Protein ◽  
Cell Types ◽  
Secretory Cells ◽  
Mucous Secretion ◽  
Cell Type ◽  
The Common ◽  
First Time ◽  
Histochemical Characterization

The present study aims at providing a detailed description of the histology, as well as the first histochemical characterization, of the secretory cells of the epidermis, pharynx, and copulatory organs of Choeradoplana iheringi, in order to give further support to studies on the physiology of these organs. The secretory cells are distinguished on the basis of secretion morphology and its staining properties, using trichrome methods and histochemical reactions. Four cell types open through the epidermis of Ch. iheringi, three of them secreting basic protein and a fourth containing glycosaminoglycan mucins. The epidermal lining cells store glycogen. In the pharynx, four secretory cell types were distinguished. Two types produce glycoprotein, a third type secretes basic protein, and another one produces glycosaminoglycan mucins. In the male copulatory organs, the prostatic vesicle receives four secretory cell types containing basic protein, except for one type which produces glycoprotein. The two secretory cell types opening into the male atrium secrete, respectively, glycoprotein, and glycosaminoglycan mucins. In the female copulatory organs, the female atrium and its proximal diverticulum, the vagina, receive two types of secretory cells producing, respectively, basic protein and glycosaminoglycan mucins. Another secretory cell type constitutes the so-called shell glands which open into the common glandular duct, secreting basic protein. The lining cells of the male and female atria produce a mucous secretion containing glycosaminoglycans. In addition, the lining epithelium of the female atrium presents an apical secretion of a proteic nature. The occurrence of a kind of spermatophore is reported for the first time for a species of Choeradoplana. This structure is located in the male or female atria in different specimens, and characterized by erythrophil, xanthophil, and/or mixed secretions associated with sperm.

scholarly journals Enzymatic synthesis and characterization of polycaprolactone by using immobilized lipase onto a surface-modified renewable carrier

2016 ◽  
Vol 18 (3) ◽  
pp. 134-140 ◽  
Author(s):  
Cansu Ulker ◽  
Nurefsan Gokalp ◽  
Yuksel Guvenilir
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Immobilized Lipase ◽  
Covalent Binding ◽  
Aqueous Media ◽  
Energy Saving Process ◽  
Surface Modified ◽  
First Time ◽  
Polymerization Conditions

Abstract In the present study, rice husk ash, which is a renewable and abundant material, was utilized as a carrier for lipase immobilization for the first time. Poly (ε-caprolactone) synthesis was successfully achieved by the new enzymatic catalyst: Candida antarctica lipase B immobilized onto surface-modified rice husk ashes by covalent binding. It was aimed to obtain optimum polymerization conditions at which highest molecular weight was reached and characterize the polymer produced. Moreover, thermal stability and effectiveness of the new biocatalyst in non-aqueous media were also shown with successful polymerization reactions. In addition, by using the new enzyme preparation, ε-caprolactone was able to be polymerized even at 30°C, which was promising for an energy saving process. Consequently, this work provides a new alternative route for poly (ε-caprolactone) synthesis.

Rescuing Psychoanalysis from Freud: The Common Project of Stekel, Jung and Ferenczi

2006 ◽  
Vol 8 (1) ◽  
pp. 125-159 ◽  
Author(s):  
Peter L. Rudnytsky
Keyword(s):  
Final Section ◽  
Harmful Effect ◽  
The Third ◽  
Psychological Analysis ◽  
History Of ◽  
The Common ◽  
Key Events ◽  
First Time ◽  
Extended Discussion

This article offers an extended discussion of Wilhelm Stekel's ‘On the History of the Analytic Movement’ (1926), published in English translation for the first time in Psychoanalysis and History 7(1) in 2005. It begins with a critique of the presentation of Stekel's text by Jaap Bos,who takes a purely rhetorical approach that seeks to exclude a psychological analysis of the author's motives. Bos's characterization of Stekel is likewise contested as unduly negative in crucial respects. The second section argues that it remains the task of the historian to search for truth. Attacks on the credibility of Jung by Harold Blum and Kurt Eissler are shown to reflect a bias that causes them to neglect the empirical evidence corroborating Jung's testimony concerning key events in his relationship to Freud. The third section lays out the numerous ways in which Stekel, Jung and Ferenczi independently arrived at remarkably similar judgements concerning Freud's character, and how his human failings exerted a harmful effect on the development of psychoanalysis. The final section moves to a discussion of how Stekel joins with Jung and Ferenczi in defining a common project of rescuing what is best in psychoanalysis from Freud's demands for personal loyalty and his attempts to subjugate his followers to intellectual tyranny.

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