scholarly journals Plastic toy soldiers, a lost battle? – an analytical perspective

2020 ◽  
Author(s):  
António Pereira ◽  
António Candeias ◽  
Ana Cardoso ◽  
José Mirão ◽  
Ana Teresa Caldeira
Keyword(s):  
Degradation Products ◽  
Degradation Process ◽  
Museum Collections ◽  
Triphenyl Phosphate ◽  
1H And 13C Nmr ◽  
Accelerated Degradation ◽  
Composition And Structure ◽  
Analytical Perspective ◽  
Morphologic Analysis

The conservation and preservation of museum collections requires a detailed understanding of their constituent materials which are often natural, synthetic or semi-synthetic polymers. The use of a wide variety of instrumental techniques can give an extraordinary amount of quality information, by delivering complementary data regarding composition and structure. This study was triggered by the Oporto Military Museum (Museu Militar do Porto) conservators who observed that a set of plastic toy soldiers dating back to the middle of the 20th century from the museum exhibition started to present severe and accelerated degradation process. With this is mind, the authors envisaged a methodology for the characterisation of these soldier toys that compromised elemental, structural and morphologic analysis, to allow the identification of polymers, their additives, and the degradation products. The methodology comprised stereoscopic microscopy and VP-SEM-EDS to recognize the micromorphology, ATR-FTIR to identify the polymer, 1H and 13C NMR to identify their additives, and micro-XRD to identify degradation products with a crystal structure. With this complementary analytical approach the composition of the toy soldiers was identified as being made of cellulose acetate plastic with triphenyl phosphate and dimethyl phthalate as major additives, and crystallyne efflorescence of triphenyl phosphate were identified as a degradation product. This methodology shows to be very adequate for a detailed characterization of plastic artefacts in museum environments.

Stability-Indicating HILIC Method for the Determination of Citicoline and Characterization of its Degradation Products by LC–MS/TOF, 1H and 13C NMR

2017 ◽  
Vol 80 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Sofiane Derbouz ◽  
Moulay-Hassane Guermouche ◽  
Saliha Guermouche
Keyword(s):  
13C Nmr ◽  
Degradation Products ◽  
1H And 13C Nmr ◽  
Stability Indicating

Characterization of dissolved material during the initial phase of softwood kraft pulping

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 37-43 ◽  
Author(s):  
HANNU PAKKANEN ◽  
TEEMU PALOHEIMO ◽  
RAIMO ALÉN
Keyword(s):  
Mass Transfer ◽  
Molecular Mass ◽  
Initial Phase ◽  
Degradation Products ◽  
Kraft Pulping ◽  
Reaction Products ◽  
Cooking Temperature ◽  
Molecular Masses ◽  
Aliphatic Carboxylic Acids

The influence of various cooking parameters, such as effective alkali, cooking temperature, and cooking time on the formation of high molecular mass lignin-derived and low molecular mass carbohydrates-derived (aliphatic carboxylic acids) degradation products, mainly during the initial phase of softwood kraft pulping was studied. In addition, the mass transfer of all of these degradation products was clarified based on their concentrations in the cooking liquor inside and outside of the chips. The results indicated that the degradation of the major hemicellulose component, galactoglucomannan, typically was dependent on temperature, and the maximum degradation amount was about 60%. In addition, about 60 min at 284°F (140°C) was needed for leveling off the concentrations of the characteristic reaction products (3,4-dideoxy-pentonic and glucoisosaccharinic acids) between these cooking liquors. Compared with low molecular mass aliphatic acids, the mass transfer of soluble lignin fragments with much higher molecular masses was clearly slower.

Fabrication and Characterization of Nife Thin Film Composition Modulated Alloys

1996 ◽  
Vol 451 ◽  
Author(s):  
S. D. Leith ◽  
D. T. Schwartz
Keyword(s):  
Rotation Rate ◽  
Stripping Voltammetry ◽  
Rotating Disk ◽  
Oscillation Period ◽  
Rotating Disk Electrode ◽  
Disk Rotation ◽  
Rate Oscillation ◽  
Composition And Structure ◽  
Spatially Periodic

ABSTRACTDescribed are results showing that an oscillating flow-field can induce spatially periodic composition variations in electrodeposited NiFe films. Flow-induced NiFe composition modulated alloys (CMA's) were deposited on the disk of a rotating disk electrode by oscillating the disk rotation rate during galvanostatic plating. Deposit composition and structure were investigated using potentiostatic stripping voltammetry and scanning probe microscopy. Results illustrate a linear relationship between the composition modulation wavelength and the flow oscillation period. CMA's with wavelengths less than 10 nm can be fabricated when plating with a disk rotation rate oscillation period less than 3 seconds.

Synthesis and Characterization of Potential and Degraded Impurities of Regadenoson

2020 ◽  
Vol 16 (8) ◽  
pp. 1130-1139
Author(s):  
Singaram Sathiyanarayanan ◽  
Chidambaram Subramanian Venkatesan ◽  
Senthamaraikannan Kabilan
Keyword(s):  
Mass Spectra ◽  
Degradation Products ◽  
Hplc Method ◽  
Forced Degradation ◽  
Spectroscopic Techniques ◽  
A2a Adenosine Receptor ◽  
Degradation Study ◽  
Related Substances ◽  
Adenosine Receptor Agonist

Background: Regadenoson is an A2A adenosine receptor agonist that is a coronary vasodilator and commonly used as a pharmacologic cardiac stressing agents. Methods: HPLC method was used for the analysis of related substances. The degraded impurities during the process were isolated and characterized by IR, Mass and NMR spectral analysis. Results: Forced degradation study of regadenoson under conditions of hydrolysis (neutral, acidic and alkaline) and oxidations suggested in the ICH Q1A(R2) was accomplished. The drug showed significant degradation under all the above conditions. On the whole, five novel degradation products were found under diverse conditions along with process related impurities which were not reported earlier. Conclusion: All the degradation products were well characterized by using advanced spectroscopic techniques like IR, 1H NMR, 13C NMR and Mass spectra. The identification of these impurities will be productive for the quality control during the production and stability behavior of the regadenoson drug substance.

Characterization of stress degradation products of nintedanib by UPLC, UHPLC-Q-TOF/MS/MS and NMR: evidence of a degradation product with a structure alert for mutagenicity

2021 ◽  
pp. 114037
Author(s):  
Vivek Dhiman ◽  
Ankit Balhara ◽  
Saranjit Singh ◽  
Shristy Tiwari ◽  
Samanthula Gananadhamu ◽  
...  
Keyword(s):  
Degradation Product ◽  
Degradation Products ◽  
Stress Degradation ◽  
Tof Ms

scholarly journals Longitudinal Characterization of the Gut Bacterial and Fungal Communities in Yaks

2021 ◽  
Vol 7 (7) ◽  
pp. 559
Author(s):  
Yaping Wang ◽  
Yuhang Fu ◽  
Yuanyuan He ◽  
Muhammad Fakhar-e-Alam Kulyar ◽  
Mudassar Iqbal ◽  
...  
Keyword(s):  
Natural Aging ◽  
Fungal Communities ◽  
Significant Shift ◽  
Mature Adult ◽  
Bacterial Phyla ◽  
Development Stages ◽  
Composition And Structure ◽  
Intestinal Functions ◽  
Development Phases

Development phases are important in maturing immune systems, intestinal functions, and metabolism for the construction, structure, and diversity of microbiome in the intestine during the entire life. Characterizing the gut microbiota colonization and succession based on age-dependent effects might be crucial if a microbiota-based therapeutic or disease prevention strategy is adopted. The purpose of this study was to reveal the dynamic distribution of intestinal bacterial and fungal communities across all development stages in yaks. Dynamic changes (a substantial difference) in the structure and composition ratio of the microbial community were observed in yaks that matched the natural aging process from juvenile to natural aging. This study included a significant shift in the abundance and proportion of bacterial phyla (Planctomycetes, Firmicutes, Bacteroidetes, Spirochaetes, Tenericutes, Proteobacteria, and Cyanobacteria) and fungal phyla (Chytridiomycota, Mortierellomycota, Neocallimastigomycota, Ascomycota, and Basidiomycota) across all development stages in yaks. As yaks grew older, variation reduced, and diversity increased as compared to young yaks. In addition, the intestine was colonized by a succession of microbiomes that coalesced into a more mature adult, including Ruminococcaceae_UCG-005, Romboutsia, Prevotellaceae_UCG-004, Blautia, Clostridium_sensu_stricto_1, Ruminococcus_1, Ruminiclostridium_5, Rikenellaceae_RC9_gut_group, Alloprevotella, Acetitomaculum, Lachnospiraceae_NK3A20_group, Bacteroides, Treponema_2, Olsenella, Escherichia-Shigella, Candidatus_Saccharimonas, and fungal communities Mortierella, Lomentospora, Orpinomyces, and Saccharomyces. In addition, microorganisms that threaten health, such as Escherichia-Shigella, Mortierella, Lomentospora and Hydrogenoanaerobacterium, Corynebacterium_1, Trichosporon, and Coprinellus, were enriched in young and old yaks, respectively, although all yaks were healthy. The significant shifts in microflora composition and structure might reflect adaptation of gut microbiome, which is associated with physicochemical conditions changes and substrate availability in the gut across all development periods of yaks.

scholarly journals Synthesis and Structural Characterization of (E)-4-[(2-Hydroxy-3-methoxybenzylidene)amino]butanoic Acid and Its Novel Cu(II) Complex

Molbank ◽  
10.3390/m1179 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1179
Author(s):  
Eleftherios Halevas ◽  
Antonios Hatzidimitriou ◽  
Barbara Mavroidi ◽  
Marina Sagnou ◽  
Maria Pelecanou ◽  
...  
Keyword(s):  
Schiff Base ◽  
Gamma Aminobutyric Acid ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Polymeric Compound ◽  
Bridging Ligands ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
Ft Ir

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.

scholarly journals Structural Studies of the Lipopolysaccharide of Aeromonas veronii bv. sobria Strain K133 which Represents New Provisional Serogroup PGO1 Prevailing among Mesophilic Aeromonads on Polish Fish Farms

2021 ◽  
Vol 22 (8) ◽  
pp. 4272
Author(s):  
Katarzyna Dworaczek ◽  
Maria Kurzylewska ◽  
Magdalena Laban ◽  
Dominika Drzewiecka ◽  
Agnieszka Pękala-Safińska ◽  
...  
Keyword(s):  
Epidemiological Data ◽  
13C Nmr Spectroscopy ◽  
Freshwater Species ◽  
Fish Farms ◽  
1H And 13C Nmr ◽  
Aeromonas Veronii ◽  
Specific Polysaccharide ◽  
O Antigens ◽  
Unique Composition

In the present work, we performed immunochemical studies of LPS, especially the O-specific polysaccharide (O-PS) of Aeromonas veronii bv. sobria strain K133, which was isolated from the kidney of carp (Cyprinus carpio L.) during an outbreak of motile aeromonad infection/motile aeromonad septicemia (MAI/MAS) on a Polish fish farm. The structural characterization of the O-PS, which was obtained by mild acid degradation of the LPS, was performed with chemical methods, MALDI-TOF mass spectrometry, and 1H and 13C NMR spectroscopy. It was revealed that the O-PS has a unique composition of a linear tetrasaccharide repeating unit and contains a rarely occurring sugar 2,4-diamino-2,4,6-trideoxy-D-glucose (bacillosamine), which may determine the specificity of the serogroup. Western blotting and ELISA confirmed that A. veronii bv. sobria strain K133 belongs to the new serogroup PGO1, which is one of the most commonly represented immunotypes among carp and trout isolates of Aeromonas sp. in Polish aquacultures. Considering the increase in the MAI/MAS incidences and their impact on freshwater species, also with economic importance, and in the absence of an effective immunoprophylaxis, studies of the Aeromonas O-antigens are relevant in the light of epidemiological data and monitoring emergent pathogens representing unknown antigenic variants and serotypes.

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