scholarly journals Stability of Glutaraldehyde in Biocide Compositions

2020 ◽  
Vol 21 (9) ◽  
pp. 3372
Author(s):  
Alina Matei ◽  
Cristina Puscas ◽  
Iulia Patrascu ◽  
Maria Lehene ◽  
Julia Ziebro ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Density Functional ◽  
Theoretical Data ◽  
Dependent Manner ◽  
Chemical Equilibria ◽  
Sds Page ◽  
The Stability ◽  
Hospital Wastewaters ◽  
Over Time

Glutaraldehyde (GA) is used as biocide in hospitals. Recent public investigations on the chemical composition of biocides used in Romania have in some cases found GA, as a key ingredient, to be apparently diluted. However, these data did not explicitly consider the complex chemical equilibria inherent to GA. An investigation of experimental and theoretical data is reported here, assessing the stability of GA solutions relevant for biocide compositions. GA solutions of various chemical composition and under varying circumstances were analyzed using spectroscopy (UV-VIS, Raman, NMR) coupled with density functional theory (DFT) calculations, as well as chemically, such as via the formation of imines in reaction/titration with glycine monitored at 270 nm; using LC-MS; or using SDS-PAGE analysis with GA as reagent in the polymerization of two test proteins- hemoglobin and myoglobin. The spectral properties of GA changed significantly over time, in a temperature-dependent manner; titration with glycine confirmed the spectral data. SDS-PAGE experiments demonstrated a non-linear and apparently unpredictable change in the reactivity of GA over time. The results may be relevant for the determination of GA concentration in various settings such as biocide analysis, hospital wastewaters, and others.

scholarly journals Plasma adrenocorticotropic hormone concentration in horses decreases after freezing for 60 days

2019 ◽  
Vol 31 (6) ◽  
pp. 856-858
Author(s):  
John C. Haffner ◽  
Dwana L. Neal ◽  
Rhonda M. Hoffman ◽  
Steven T. Grubbs
Keyword(s):  
Repeated Measures ◽  
Adrenocorticotropic Hormone ◽  
Mixed Model ◽  
Statistical Significance ◽  
Hormone Concentration ◽  
Plasma Acth ◽  
Acth Concentration ◽  
The Stability ◽  
Over Time

We investigated the stability of adrenocorticotropic hormone (ACTH) in plasma after freezing for different lengths of time. The plasma ACTH concentrations of 12 horses were measured on day 0 (baseline) and over time, after stimulation with thyrotropin-releasing hormone. Samples were stored at −80°C for 3, 7, 30, 60, and 90 d, or at −20°C for 3, 7, 30, and 60 d, or between ice packs at −20°C for 3 and 7 d prior to determination of ACTH concentration. ACTH concentrations were compared to baseline (non-frozen day 0 plasma) for each storage method using a mixed model with repeated measures in which each horse served as its own control and day was the repeated effect. Statistical significance was set at p ≤ 0.05, and 0.05 < p < 0.10 was considered a trend. Plasma ACTH frozen at −20°C or at −80°C resulted in degradation of ACTH compared to baseline samples at 60 and 90 d respectively. There was no degradation of ACTH after 7 d when stored between ice packs, or before 30 d at −20°C, or before 60 d at −80°C.

Evaluations of Job-Related Descriptors across Time and between Sexes

1985 ◽  
Vol 57 (3_suppl) ◽  
pp. 1195-1201 ◽  
Author(s):  
Edward A. Ward
Keyword(s):  
Sex Differences ◽  
Performance Appraisal ◽  
Men And Women ◽  
The Stability ◽  
Over Time

The stability of evaluations of job-related descriptors across 24 yr. was investigated along with a determination of present sex differences in such evaluations. The desirability ratings of 129 job-related descriptors which had been evaluated in 1961 were compared to effectiveness ratings of the same job-related descriptors by men and women raters in 1985. A total of 128 men and 73 women served as raters. Analysis indicated that evaluations are reasonably stable across time and present sex differences are negligible. This implies that research on performance appraisal using ratings of job-related descriptors is valid over time and that women and men evaluate job-related descriptors in a similar manner.

scholarly journals Temporal stability of primate scent samples

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Alice C. Poirier ◽  
John S. Waterhouse ◽  
Jacob C. Dunn ◽  
Andrew C. Smith
Keyword(s):  
Chemical Composition ◽  
Room Temperature ◽  
Solid Phase ◽  
Temporal Stability ◽  
Gas Chromatography Mass Spectrometry ◽  
Headspace Gas ◽  
The Stability ◽  
Natural Decay ◽  
Over Time

AbstractA common recommendation in the field of animal chemosignaling is to store and transport scent samples frozen, since they are likely to change with time and degrade due to bacterial activity inside the sample containers and the loss of the most volatile compounds. However, we still ignore the exact pattern of change or degradation for these types of samples. Here we experimentally tested the stability of primate scent samples during analytical procedures. For this purpose, we used swabs of naturally deposited glandular secretions from captive tamarins (Neotropical primates) analyzed by headspace gas chromatography-mass spectrometry. We successively extracted the samples by solid-phase microextraction, while controlling for the delay between extractions, and compared the number of compounds detected in the samples under each condition. We found that compounds were lost and transformed over time inside the sample vials. Such natural decay of scent signals is likely to contribute to the long term information transmitted. We found no evidence that long delays at room temperature affected sample chemical composition more than short delays. Nonetheless, we showed that repeated extraction of a sample increased the loss of compounds. The changes in sample chemical composition observed over time in this experiment support standard recommendation to avoid storing samples for long periods at room temperature and to extract each sample only once, in order to ensure optimum results.

scholarly journals Tales of the Unexpected: The Case of Zirconium(IV) Complexes with Desferrioxamine

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2098 ◽  
Author(s):  
Matteo Savastano ◽  
Carla Bazzicalupi ◽  
Giovanni Ferraro ◽  
Emiliano Fratini ◽  
Paola Gratteri ◽  
...  
Keyword(s):  
Stability Constants ◽  
Density Functional ◽  
Maldi Mass Spectrometry ◽  
Binuclear Complexes ◽  
X Ray Scattering ◽  
Complex Solutions ◽  
The Stability ◽  
Ph Range ◽  
First Time

The Zr4+ complexes with desferrioxamine (H3DFO) and its derivatives are the only 89Zr-based imaging agents for proton emission tomography (PET) that have been used so far in clinical trials. Nevertheless, a complete speciation of the Zr4+/H3DFO system in solution has never been performed and the stability constants of the relevant complexes are still unknown. Here we report, for the first time, the speciation of this system in water, performed by potentiometric titrations, and the determination of the stability constants of all complexes formed in the pH range 2.5–11.5. Surprisingly, although desferrioxamine gives rise to very stable 1:1 complexes with Zr4+ (logK = 36.14 for Zr4+ + DFO3− = [ZrDFO]+), 2:2 and 2:3 ones are also formed in solution. Depending on the conditions, these binuclear complexes can be main species in solution. These results were corroborated by small-angle X-ray scattering (SAXS) and MALDI mass spectrometry analyses of complex solutions. Information on complex structures was obtained by means of density functional theory (DFT) calculations.

scholarly journals Assembly intermediates of the mouse muscle nicotinic acetylcholine receptor in stably transfected fibroblasts.

1990 ◽  
Vol 111 (6) ◽  
pp. 2601-2611 ◽  
Author(s):  
P Blount ◽  
M M Smith ◽  
J P Merlie
Keyword(s):  
Acetylcholine Receptor ◽  
Nicotinic Acetylcholine Receptor ◽  
Lectin Binding ◽  
Dependent Manner ◽  
Nicotinic Acetylcholine ◽  
Mouse Muscle ◽  
A Value ◽  
Sds Page ◽  
The Stability ◽  
Alpha Bungarotoxin

We have used fibroblast clones expressing muscle nicotinic acetylcholine receptor alpha and gamma, and alpha and delta subunits to measure the kinetics of subunit assembly, and to study the properties of the partially assembled products that are formed. We demonstrate by coimmunoprecipitation that assembly intermediates in fibroblasts coexpressing alpha and delta subunits are formed in a time-dependent manner. The alpha and gamma- and the alpha and delta-producing transfected cells form complexes that, when labeled with 125I-alpha-bungarotoxin, migrate in sucrose gradients at 6.3S, a value consistent with a hetero-dimer structure. An additional peak at 8.5S is formed from the alpha and gamma subunits expressed in fibroblasts suggesting that gamma may have more than one binding site for alpha subunit. The stability and specificity of formation of these partially assembled complexes suggests that they are normal intermediates in the assembly of acetylcholine receptor. Comparison of the binding of 125I-alpha-bungarotoxin to intact and detergent-extracted fibroblasts indicate that essentially all of the binding sites are retained in an intracellular pool. The fibroblast delta subunit has the electrophoretic mobility in SDS-PAGE of a precursor that does not contain complex carbohydrates. In addition, alpha gamma and alpha delta complexes had lectin binding properties expected of subunits lacking complex oligosaccharides. Therefore, fibroblasts coexpressing alpha and gamma or alpha and delta subunits produce discrete assembly intermediates that are retained in an intracellular compartment and are not processed by Golgi enzymes.

Investigation of Surface Phase Layers on GaAs after Selective Chemical Etching

2015 ◽  
Vol 1085 ◽  
pp. 91-94
Author(s):  
Oksana N. Zarubina ◽  
Gennady M. Mokrousov ◽  
Alexander G. Touryanski ◽  
Igor V. Pirshin ◽  
Liubov V. Maliy
Keyword(s):  
Phase Distribution ◽  
Theoretical Data ◽  
Selective Dissolution ◽  
Phase Layers ◽  
Interfacial Boundary ◽  
Combination Of Methods ◽  
Elemental Arsenic ◽  
The Stability ◽  
First Time

Normal 0 false false false RU X-NONE X-NONE The combination of methods of voltammetry, Raman spectroscopy, and X-ray reflectometry for the first time has been applied for the more comprehensive investigation of interfacial boundaries of GaAs, i.e. determination of phase distribution and thickness of the phase layers. The conditions for the formation of elemental arsenic on a GaAs surface in the process of selective dissolution are discussed. The stability of interfacial boundaries in air has also been studied. The investigations have shown that air storage lead to the oxidation of formed As0 and reorganization of GaAs interfacial boundary accompanied by the formation of Ga2O3 and As0 as a result of a reaction between As2O3 and GaAs. The results on interfacial boundaries composition were found to be correlated with the theoretical data. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Обычная таблица"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

scholarly journals An HPLC and UHPLC-HRMS Approach to Study PSMA-11 Instability in Aqueous Solution

2020 ◽  
Author(s):  
ANTONELLA IUDICELLO ◽  
Filippo Genovese ◽  
Valentina Di Iorio ◽  
Gianfranco Cicoria ◽  
Stefano Boschi
Keyword(s):  
Analytical Method ◽  
Radiochemical Purity ◽  
Time Dependent ◽  
Dependent Manner ◽  
Compound Structure ◽  
High Affinity ◽  
Secondary Compound ◽  
The Stability ◽  
Definition Of

Abstract Background. Stability of precursors and reagents are of utmost importance for developing a suitable, fast and routinely reproducible analytical method for the quality control of radiopharmaceuticals, for the validation of the analytical method itself, as well as for radiolabeling procedure. During the validation of the analytical method used for the determination of chemical and radiochemical purity of an injectable solution of 68Ga-PSMA-11, a trend to instability of the PSMA-11 standard, the same used as a precursor in the radiosynthesis of 68Ga-PSMA11, has been found. This instability led to the formation of a secondary compound in a time-dependent manner. The formation of this compound made difficult the validation of the analytical method and influenced the radiolabeling yield, by increasing free 68Ga which, obviously, decreased the final yield.Results. The nature of this compound was investigated by adding chelators, such as EDTA, to PSMA-11 solutions and by using the combination of UHPLC-HRMS. The results led to the definition of the secondary compound structure, as natFe-PSMA-11, from the combination of the high affinity chelator HBED-CC, present in the molecule of PSMA-11, and environmental Fe(III).Conclusions. Strategies to reduce the risk of low radiolabeling yields and to increase the stability of the standards were also discussed.

Hydrogenation of Nanodiamond Surfaces: Structure and Effects on Crystalline Stability

2003 ◽  
Vol 10 (02n03) ◽  
pp. 233-239 ◽  
Author(s):  
S. P. Russo ◽  
A. S. Barnard ◽  
I. K. Snook
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Atomic Layer ◽  
Parallel Computer ◽  
Generalized Gradient ◽  
Functional Theory ◽  
First Approximation ◽  
The Stability ◽  
Bulk Diamond

Presented are results of our ab initio study of the surface reconstruction and relaxation of (100) surfaces on bulk and nanocrystalline diamond. We have used a density functional theory (DFT) within the generalized-gradient approximation (GGA) via the parallel computer version of the Vienna ab initio simulation package (VASP), to consider dehydrogenated and hydrogenated surfaces. Edges and corners of nanocrystals offer a new challenge in the determination of surface structure. We have applied the methodology for stepped diamond (100) surfaces to this problem, and consider it useful in describing nanodiamond edges and corners to first approximation. Our results also indicate that dimer lengths and atomic layer depths of the C(100)(2 × 1) and C(100)(2 × 1):H nanodiamond surfaces differ slightly from those of bulk diamond. The effects of these differences on crystalline stability are discussed, with the intension of offering a better understanding of the effects of nanodiamond surfaces on the stability of diamondoid nanostructures.

On the Robustness of Solution Strategy Classifications

2010 ◽  
Vol 31 (2) ◽  
pp. 68-73 ◽  
Author(s):  
María José Contreras ◽  
Víctor J. Rubio ◽  
Daniel Peña ◽  
José Santacreu
Keyword(s):  
Individual Differences ◽  
Study Strategies ◽  
Solution Strategy ◽  
Specific Test ◽  
Spatial Tasks ◽  
The Stability ◽  
Strategy Changes ◽  
Over Time

Individual differences in performance when solving spatial tasks can be partly explained by differences in the strategies used. Two main difficulties arise when studying such strategies: the identification of the strategy itself and the stability of the strategy over time. In the present study strategies were separated into three categories: segmented (analytic), holistic-feedback dependent, and holistic-planned, according to the procedure described by Peña, Contreras, Shih, and Santacreu (2008) . A group of individuals were evaluated twice on a 1-year test-retest basis. During the 1-year interval between tests, the participants were not able to prepare for the specific test used in this study or similar ones. It was found that 60% of the individuals kept the same strategy throughout the tests. When strategy changes did occur, they were usually due to a better strategy. These results prove the robustness of using strategy-based procedures for studying individual differences in spatial tasks.

On the Stability of Evaluative Conditioning Effects

2013 ◽  
Vol 44 (6) ◽  
pp. 380-389 ◽  
Author(s):  
Sabine Förderer ◽  
Christian Unkelbach
Keyword(s):  
Evaluative Conditioning ◽  
Indirect Measures ◽  
The Stability ◽  
Over Time

Evaluative conditioning (EC) refers to valence changes in neutral stimuli (CSs) through repeated pairing with liked or disliked stimuli (USs). The present study examined the stability of EC effects in the course of 1 week. We investigated how this stability depends on memory for US valence and US identity. We also investigated whether CSs evaluations occurring immediately after conditioning (i.e., evaluative consolidation) are necessary for stable EC effects. Participants showed stable EC effects on direct and indirect measures, independent of evaluations immediately after conditioning. EC effects depended on memory for US valence but not for US identity. And although memory decreased significantly over time, EC effects remained stable. These data suggest that evaluative consolidation is not necessary, and that conditioned preferences and attitudes might persist even when people do not remember the concrete source anymore.

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