scholarly journals Accelerated aging of forensically relevant biological materials on swabs

BioTechniques ◽  
2021 ◽  
Vol 70 (4) ◽  
pp. 233-238
Author(s):  
Abigail S Bathrick ◽  
Jon M Davoren
Keyword(s):  
Biological Samples ◽  
Accelerated Aging ◽  
Biological Materials ◽  
Quality Metrics ◽  
Forensic Evidence ◽  
Evidence Type ◽  
Biological Evidence ◽  
The Stability ◽  
Forensic Testing ◽  
Time Frames

The preservation of DNA in biological samples is important for forensic testing, as samples can be tested years or even decades after collection. Generally, the DNA within biological evidence is stable over shorter time frames but can degrade over extended periods. In this work, we evaluated accelerated aging as a method to reduce the duration of studies examining the stability of DNA in forensic evidence-type samples. Evaluation of the DNA extracted from cells stored at 37 and 50°C for 194 or 79 days, respectively, showed similar quality metrics to cells stored at 25°C for 548 days.

THE DEVELOPMENT OF A METHOD FOR DIRECT MASS SPECTROMETRIC ANALYSIS OF BIOLOGICAL SAMPLES USING POROUS SAMPLERS

2021 ◽  
Vol 55 (1) ◽  
pp. 99-103
Author(s):  
R.E. Levin ◽  
◽  
M.A. Shamraeva ◽  
I.M. Larina ◽  
D.S. Bormotov ◽  
...  
Keyword(s):  
Biological Samples ◽  
Biological Fluids ◽  
Storage Conditions ◽  
Spectrometric Analysis ◽  
Sample Collection ◽  
Mucous Membranes ◽  
The Status ◽  
Direct Mass Spectrometry ◽  
The Stability ◽  
Blood Spot

The paper presents a method for rapid multi-omics investigation of biological samples using polypropylene bulk porous samplers. The use of porous samplers makes it easy to collect samples from the surface of the skin, mucous membranes, and biological fluids even in a field, and the surfaces of wounds and injuries. Collected samples do not require special storage conditions, and the samplers are lightweight and very compact. They can be used to monitor the condition of cosmonauts before, during, and after the spaceflight with the same sample collection method. The analysis of biomaterial applied to the sampler is performed using direct mass spectrometry methods, similar to the dried blood spot technique that is already used in clinical practice. However, bulk porous samplers allow expanding the range of analytes ionization conditions, which increases the stability and reliability of the ionization process, which expands the variety of analyzed molecules. The proposed method can be used to study compounds of various classes, including proteins, lipids, and metabolites, to systematically monitor the status of people in extreme conditions (athletes, astronauts), or to study the condition of patients in the clinic.

Aging and Fatigue of Aerosol Jet-Printed Nano-Ag Traces on Flexible Substrate

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Arun Raj ◽  
Rajesh Sharma Sivasubramony ◽  
Manu Yadav ◽  
Sanoop Thekkut ◽  
Gurvinder Singh Khinda ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Selection Process ◽  
Flexible Substrate ◽  
Accelerated Aging ◽  
Organic Matrix ◽  
Subsequent Aging ◽  
Long Term Storage ◽  
Order Of Magnitude ◽  
Sintering Conditions ◽  
The Stability

Abstract Conducting traces on a flexible substrate often have to survive significant and repeated deformation, making their fatigue resistance and the stability of it during long-term storage and use a potential concern. The question of stability is obvious in the case of, for example, screen or ink jet-printed traces where the organic matrix remains a critical part of the structure. We show it also to be important for nano-Ag traces that are sintered to ensure metallic bonding between the particles while eliminating most of the organics. We also show conventional accelerated aging tests to be potentially confusing or misleading for such traces, depending among other on practical limitations on sintering conditions. Examples are presented of how the fatigue resistance of application relevant aerosol jet-printed nano-Ag traces may degrade relatively rapidly at moderate temperatures. Even after “optimized” sintering at a much higher temperature subsequent aging at 75 °C for only 100 h led to an order of magnitude reduction in the fatigue life in subsequent mild cycling. The rate of degradation is certain to vary with the design and the ink used as well as with sintering conditions, making it important to account for it all in materials selection, process optimization, and assessments of practical life.

scholarly journals Buckling Behaviors of Staggered Nanostructure of Biological Materials

2015 ◽  
Vol 83 (3) ◽  
Author(s):  
Zhiling Bai ◽  
Yewang Su ◽  
Baohua Ji
Keyword(s):  
Aspect Ratio ◽  
Mechanical Model ◽  
Volume Fraction ◽  
Biological Materials ◽  
Protein Matrix ◽  
Buckling Strength ◽  
Upper Limits ◽  
Staggered Arrangement ◽  
The Stability ◽  
Peak Value

The nanostructure of biological materials is built with hard mineral crystals embedded in soft protein matrix in a staggered manner. The staggered arrangement of the crystals is assumed to be critically important for the stability of the nanostructure. But the mechanism is not fully understood. In this paper, a mechanical model, considering the effects of overlapping ratio between the crystals, i.e., the staggering position, is developed for analyzing the buckling behaviors of the nanostructure. It is found that the buckling strength increases with the overlapping ratio λ in the range of 0–1/2 and reaches a peak value at λ = 1/2 that is generally adopted by nature's design of the biological materials. The effect of aspect ratio and volume fraction of mineral crystals are further analyzed at various overlapping ratios, and the results are in general consistent with previous studies for the case of λ = 1/2. In addition, the lower and upper limits of the buckling strength are obtained. Finally, we show that the contact between mineral tips can significantly enhance the buckling strength of the nanostructure when the aspect ratio of minerals is small.

Longitudinal associations of hopelessness and loneliness in older adults: results from the US health and retirement study

2017 ◽  
Vol 29 (9) ◽  
pp. 1451-1459 ◽  
Author(s):  
Amber M. Gum ◽  
Sharon Shiovitz-Ezra ◽  
Liat Ayalon
Keyword(s):  
Later Life ◽  
Health And Retirement Study ◽  
Small Magnitude ◽  
Simultaneous Evaluation ◽  
The Us ◽  
Lagged Effects ◽  
The Stability ◽  
Time Frames ◽  
Retirement Study ◽  
Lagged Effect

ABSTRACTBackground:Hopelessness and loneliness are potent risk factors for poor mental and physical health in later life, although the nature of their relationships with each other over time is not clear. The aim of the current study was to examine relationships between hopelessness and loneliness over an eight-year study period.Methods:Three waves of data from the US Health and Retirement Study (2006, 2010, 2014) were used to test a cross-lagged model of hopelessness and loneliness (N= 7,831), which allows for the simultaneous evaluation of the reciprocal associations of loneliness and hopelessness. Age in 2006, gender, years of education, number of medical conditions, and depressive symptoms were included as covariates.Results:The autoregressive effects of loneliness (B(SE) = 0.63 (0.02),p< 0.001) and hopelessness (B(SE) = 0.63 (0.02),p< 0.001) were substantive and significant across the three waves, pointing to the stability of both constructs over the eight-year study period. The lagged effect of loneliness on hopelessness was non-significant (B(SE) = 0.05 (0.03),p= 0.16), whereas the lagged effect of hopelessness on loneliness was significant (B(SE) = 0.01 (0.01),p= 0.03). These lagged effects were not significantly different from each other, however, χ2(1) = 2.016,p= 0.156.Conclusions:Participants who were more hopeless tended to become lonelier four years later, but lonelier participants did not become more hopeless four years later. Findings are tentative given the small magnitude and lack of difference between the cross-lagged effects. Future directions include replicating these findings in different samples and time frames, examining potential mechanisms of relationships between hopelessness and loneliness, and potential intervention strategies that might improve both conditions.

scholarly journals An automated chromatography procedure optimized for analysis of stable Cu isotopes from biological materials

2016 ◽  
Vol 31 (10) ◽  
pp. 2023-2030 ◽  
Author(s):  
T. Gabriel Enge ◽  
M. Paul Field ◽  
Dianne F. Jolley ◽  
Heath Ecroyd ◽  
M. Hwan Kim ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ion Exchange ◽  
Stable Isotope Analysis ◽  
Biological Samples ◽  
Isotope Analysis ◽  
Biological Materials ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Chromatography Method ◽  
Cu Isotopes

An automated ion-exchange chromatography method is presented for the separation of copper from biological samples for stable, isotope analysis.

scholarly journals Analysis of Biological Samples in a Contemporary Laboratory Practice (Review)

2019 ◽  
Vol 8 (2) ◽  
pp. 115-120
Author(s):  
I. I. Miroshnichenko ◽  
Y. E. Shilov
Keyword(s):  
Mass Spectrometry ◽  
Biological Samples ◽  
Mobile Phase ◽  
High Performance ◽  
Biomarker Discovery ◽  
Parent Compound ◽  
Mass Spectrometric ◽  
Chromatography Mass Spectrometry ◽  
Carry Over ◽  
The Stability

Introduction. In the present publication highlights the key points of the main stages of development of methods for determining trace amounts of drugs and metabolites in biological samples using chromatographic and chromatography-mass spectrometry methods. The main sources of errors are specified. The main attention is paid to chromatography-mass spectrometry, which is the basic method of analysis of small molecules in biological samples. Examples from literary sources and authors' own practice are given.Text. The review highlights some of the practical issues of preparation of calibration samples, method of increasing the stability of the sample at the stage of sampling and plasma preparation. In particular, the influence of various anticoagulants on the accuracy of the analysis is reflected. Specify the method of reducing back conversion of some metabolites of carboxyl-containing drugs to parent compound to prevent overestimation of the results of quantitative determination. Some methods of sample preparation, which have become widespread recently, are noted. For example, solid supported liquid-liquid extraction, based on the extraction of the component of interest from the water sample into the liquid layer distributed on a solid high-polar carrier, followed by eluting by a system of non-polar solvents that do not mix with this layer. Recommendations on the use of internal standards, the preparation of the mobile phase for HPLC, on chromatographic separation, validation techniques are given. In the section «Mass spectrometric detection» features of preparation of a mobile phase for chromatography-mass spectrometry experiments are given. The questions of carry-over reduction, ion suppression, matrix effect are covered. The phenomenon of cross-talk in the study of drug metabolism by chromatography-mass spectrometry is discussed. It consists in the mutual distortion of the mass spectrometric response, when the same mass fragments are formed from different ions-precursors. Features of development of techniques for high-performance pharmacokinetic screening are given.Conclusion. The authors hope that the presented material will be useful for scientists and specialists in the field of pharmacokinetics, biomarker discovery and clinical analyses.

scholarly journals Effect of Sunlight, Moisture, Temperature and Ultraviolet Radiation on the Quality Control Parameters of Ciprofloxacin Tablet Formulation

2016 ◽  
Vol 8 (3) ◽  
pp. 99 ◽  
Author(s):  
Kenneth Ezealisiji ◽  
Angenlina Pepple ◽  
Catherine Stanley
Keyword(s):  
Relative Humidity ◽  
Uv Light ◽  
Physical Stability ◽  
Accelerated Aging ◽  
Storage Conditions ◽  
Dissolution Behavior ◽  
Ciprofloxacin Hydrochloride ◽  
Label Claim ◽  
Aging Conditions ◽  
The Stability

<p>This work assesses the stability and quality of Ciprofloxacin hydrochloride tablets after subjection to accelerated stability conditions of sunlight, temperature of 40±1<sup>0</sup>C, 75% relative humidity, and UV light of 365 nm for 4 hours each day. This study was performed at time zero and at 4-day intervals for a period of 45 days (that is, days 0, 4, 8, 12…40, 44) according to the International Conference on Harmonization (ICH) accelerated aging conditions and the results obtained were subjected to statistical analysis. The results showed that with increasing time there was a gradual reduction in the dissolution rate with the tablets exposed to all four storage conditions failing the test on day 44 where they had less than 80 % release of the label claim. For content of Ciprofloxacin Hydrochloride, only those tablets exposed to UV light passed the test for all 44 days as they had a minimum of 96.83 % content on the 44<sup>th</sup> day. At day 0, all the tablets assayed passed this test, having a ciprofloxacin content of 99.43 %. For those tablets subjected to the other storage conditions including temperature of 40±1<sup>0</sup>C, 75 % relative humidity and sunlight, they had ciprofloxacin content of 70.22 %, 71.50 %, and 78.36 % respectively. The results further, indicated that the storage conditions used in the study had a greater impact on the dissolution behavior and content of the Ciprofloxacin tablets than they did on the physical stability (hardness, uniformity of weight, disintegration).</p>

4-Channel Digital Positron Lifetime Spectrometer for Studying Biological Samples

2008 ◽  
Vol 607 ◽  
pp. 254-256 ◽  
Author(s):  
Petri Sane ◽  
Simo Kilpeläinen ◽  
F. Tuomisto
Keyword(s):  
Service Life ◽  
Biological Samples ◽  
Positron Lifetime ◽  
Biological Materials ◽  
Low Resolution ◽  
Lifetime Component ◽  
Individual Detector

In this work a novel detector setup for PALS-studies on biomolecular materials is presented. When pursuing optimal detecting efficiency and lifetime component resolution one must make compromises when using only one detector pair. With smaller scintillation heads the resolution is higher, but the detecting efficiency decreases and vice versa. When measuring biological materials that do not withstand long measurement periods, sacrifices are made for gaining efficiency. The price of this optimization is low resolution of the lifetime components, namely separating the always present water’s lifetime component of ~1.8 ns from the actual material’s lifetime component, typically >2 ns. A solution to this problem is measuring the annihilation spectra with two individual detector pairs simultaneously. Using analog setup, it would require duplicate ADC-hardware that are both expensive and degrade by time. With a fully digital setup, the need for hardware is smaller and the precision of the setup is constant during its service life.

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