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Soft Matter Feb 2020When supercooled dew droplets form on a chilled surface, the subsequent freezing process is driven by a fascinating phenomenon of propagating inter-droplet ice bridges....
When supercooled dew droplets form on a chilled surface, the subsequent freezing process is driven by a fascinating phenomenon of propagating inter-droplet ice bridges. Here, we explore the range of conditions under which an individual ice dendrite can successfully bridge the gap from a frozen droplet to its nearest liquid neighbor. Ranging the droplet sizes from 1 μm-10 mm, we find that the criterion for ice bridging is purely geometric and independent of temperature, ambient humidity, and surface wettability. We model the growth of individual ice bridges as well as the global speed of percolating fronts sweeping across large droplet populations. We also give a dynamical law for dry zone formation when ice fails to bridge the gap.
PubMed: 31828263
DOI: 10.1039/c9sm01968e -
Analytical Biochemistry Nov 2020Dry ice (solid CO) remains highly useful when temperature-sensitive biological samples need to be cryogenically transported. CO released during the sublimation of dry...
Dry ice (solid CO) remains highly useful when temperature-sensitive biological samples need to be cryogenically transported. CO released during the sublimation of dry ice can diffuse through gas permeable receptacle material or any defective seals resulting in potential sample acidification and compromised integrity. In addition, the quality of cryopreservation can be undermined once the dry ice is exhausted. The dry ice carrier design described here has been demonstrated to prevent sublimated CO from reaching the samples while maintaining storage temperature below -60 °C for 19 h. It is also equipped with microcontroller-based temperature monitoring for traceability and CO gas monitoring for safety.
Topics: Carbon Dioxide; Cold Temperature; Cryopreservation; Dry Ice; Equipment Design; Humans; Hydrogen-Ion Concentration; Sublimation, Chemical; Time Factors; Transportation
PubMed: 32795454
DOI: 10.1016/j.ab.2020.113906 -
Current Protocols Essential Laboratory... Dec 2020Stored biological materials should have minimal pre-analytical variations in order to provide researchers with high-quality samples that will give reliable and...
Stored biological materials should have minimal pre-analytical variations in order to provide researchers with high-quality samples that will give reliable and reproducible results, yet methods of storage should be easy to implement, with minimal cost and health hazard. Frozen tissue samples are a valuable biological resource. Here we compare different methods, such as liquid nitrogen (LN) or dry ice (DI), to a cheap and safe alternative using an aluminum platform (AP). Murine fresh liver and pancreas tissues were used with varying lengths of warm ischemia time. Quality assessment was based on histological evaluation, DNA and RNA extraction and quantification, and RNA degradation analysis, as well preservation of antigens for immunofluorescence, in a blinded manner. Both in superficial and deep tissue sections, based on histological assessment, AP is superior to DI, or as good as LN techniques in terms of presence of ice crystals, cutting artifacts, and overall quality/structural preservation. DNA and RNA were successfully extracted in reasonable quantities from all freezing techniques, but RNA degradation was seen for pancreas samples across all techniques. Immunofluorescence with cytokeratin8 (CK-8), alpha smooth muscle actin (αSMA), CD3, and B220 shows equally good outcomes for AP and LN, which are better than DI. The aluminum platform is a cheap, yet reliable method to freeze samples, rapidly preserving histological, antigenic, and DNA/RNA quality. Wider testing is required across different sample types. © 2020 The Authors. : Flash-freezing fresh tissue with aluminum platform : Freezing fresh tissue with liquid nitrogen : Freezing fresh tissue with dry ice.
PubMed: 33381282
DOI: 10.1002/cpet.46 -
Food Science and Technology... Mar 2023This study aims to investigate some chemical, physical, textural, and aroma compounds properties of the ice-cream with berry fruits produced using classical and...
This study aims to investigate some chemical, physical, textural, and aroma compounds properties of the ice-cream with berry fruits produced using classical and molecular ice-cream production techniques. No significant difference was determined between the pH, dry solid, fat, protein, ash amounts, and overrun of the samples. However, molecular ice-creams, in particular, have a softer structure since they contain tiny ice crystals, and the first dripping and full melting time was realized in less time. The effect of added fruit variety on the viscosity value of the samples was found to be significant. It was observed that the volatile compound profiles of the ice-creams were affected differently by ice-cream production techniques. The octanoic, hexanoic, and dodecanoic acid were high-value prominent compounds in all the ice creams. Furthermore, the 14 volatile compounds that are effective in the difference between the ice-creams and their production techniques were determined, which is more important in the ice cream aroma. This is the first study on the change of the volatile compounds, hence the aroma compound profile, in molecular ice-cream production technique. And, it was presented as an innovative approach. Therefore, it is thought to be shed new light on future studies.
Topics: Ice Cream; Fruit; Viscosity
PubMed: 35379006
DOI: 10.1177/10820132221092368 -
Journal of the Science of Food and... May 2022Ice plant is a halophyte, known for its antioxidant activity and for being a highly functional food. It is capable of increasing its contents of health-promoting...
BACKGROUND
Ice plant is a halophyte, known for its antioxidant activity and for being a highly functional food. It is capable of increasing its contents of health-promoting compounds when subjected to certain stresses such as salinity. The objective of this work was to determine the plant's best growing conditions to achieve both an optimal production of bioactive metabolites and high crop yield. Mesembryanthemum crystallinum were grown under semi-controlled conditions and four saline treatments were applied at: 0, 100, 200 and 300 mmol L sodium chloride (NaCl), respectively.
RESULTS
The 100 mmol L NaCl treatment induced a slight increase in shoot dry weight (DW) and enhanced the leaf area. At higher salinity levels, however, the shoot biomass decreased. The concentration of starch and total proteins declined as the concentration of salt increased, while the total soluble sugars (TSS) content was lower in 100 and 300 mmol L NaCl treatments. Proline increased in conditions over 100 mmol L NaCl. Furthermore, plants grown with 300 mmol L of NaCl presented the highest values of glutathione, ascorbic acid and vitamin C. Antioxidant enzymes activity and total phenolics increased with the severity of the salinity.
CONCLUSION
Ice plant accumulates high levels of health-promoting compounds when grown with 300 mmol L NaCl. A high concentration of beneficial compounds, however, is detrimental to the plant's growth. Moreover, 100 mmol L NaCl treatment not only improved the concentration of bioactive and antioxidant compounds but also preserved the crop yield. It could thus be interesting to promote the cultivation of this high nutritional value plant in environments of moderate salinity. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Topics: Antioxidants; Ascorbic Acid; Mesembryanthemum; Plant Leaves; Plants, Edible; Salinity; Salt-Tolerant Plants; Sodium Chloride
PubMed: 34693528
DOI: 10.1002/jsfa.11608 -
Antioxidants (Basel, Switzerland) Apr 2023Thermal reactions can significantly alter the metabolomic and lipidomic content of biofluids and tissues during storage. In this study, we investigated the stability of...
Thermal reactions can significantly alter the metabolomic and lipidomic content of biofluids and tissues during storage. In this study, we investigated the stability of polar metabolites and complex lipids in dry human serum and mouse liver extracts over a three-day period under various temperature conditions. Specifically, we tested temperatures of -80 °C (freezer), -24 °C (freezer), -0.5 °C (polystyrene box with gel-based ice packs), +5 °C (refrigerator), +23 °C (laboratory, room temperature), and +30 °C (thermostat) to simulate the time between sample extraction and analysis, shipping dry extracts to different labs as an alternative to dry ice, and document the impact of higher temperatures on sample integrity. The extracts were analyzed using five fast liquid chromatography-mass spectrometry (LC-MS) methods to screen polar metabolites and complex lipids, and over 600 metabolites were annotated in serum and liver extracts. We found that storing dry extracts at -24 °C and partially at -0.5 °C provided comparable results to -80 °C (reference condition). However, increasing the storage temperatures led to significant changes in oxidized triacylglycerols, phospholipids, and fatty acids within three days. Polar metabolites were mainly affected at storage temperatures of +23 °C and +30 °C.
PubMed: 37237852
DOI: 10.3390/antiox12050986 -
Journal of Oral and Maxillofacial... 2023The process of decoverslipping is often required in a laboratory to review or examine an older slide which tends to fade over time, making it almost impossible to use it...
BACKGROUND
The process of decoverslipping is often required in a laboratory to review or examine an older slide which tends to fade over time, making it almost impossible to use it for research or study purposes. The sections then need to be re-stained which can only be done after removing the coverslip. The traditional method of decoverslipping using xylene is a time-consuming process. Various methods have been used in the past; however, none were found to be completely effective. Dry ice, the solid form of carbon dioxide, is an easily available, cheap cooling agent with a low freezing temperature (-78.5°C) which was evaluated for its efficacy in decoverslipping process, as an alternative to xylene.
MATERIALS AND METHOD
64 faded haematoxylin and eosin (H&E)-stained histopathology slides were randomly selected and segregated, according to duration of year, into eight major groups. Each group was further divided into four subgroups according to the time that the slides were subjected for decoverslipping. The slides were placed on dry ice and the time was set. Once the coverslip was removed, the slides were placed in xylene to remove any residual mountant. The tissue sections were evaluated for physical disfigurement followed by re-staining with H&E to check for any change in tissue morphology.
RESULT
The mean time taken for removal of coverslip using dry ice was 35 seconds.
CONCLUSION
This technique is easy, fast, and effective, with no tissue loss or compromise in staining quality, thereby preventing xylene toxicity and its effect on the environment.
PubMed: 38033942
DOI: 10.4103/jomfp.jomfp_332_22 -
Acta Tropica Jan 2023This study aimed to determine the occurrence of hemoplasmas and tick-borne pathogens (TBP) (Theileria equi, Babesia caballi, and Ehrlichia sp.) in horses and ticks'...
This study aimed to determine the occurrence of hemoplasmas and tick-borne pathogens (TBP) (Theileria equi, Babesia caballi, and Ehrlichia sp.) in horses and ticks' salivary glands, and determine the factors associated with exposure/infection in a rural settlement in southern Brazil. Blood samples from 22 horses were screened for anti-T. equi and anti-Ehrlichia sp. antibodies by an indirect fluorescent antibody test (IFAT) assays. Samples were also tested by PCR assays for T. equi and B. caballi (18S rRNA and rap-1 genes, respectively), hemoplasmas (16S rRNA gene), and Ehrlichia sp. (dsb gene). Ticks were removed from the animals (inspection) and the environment (flannel trawling and dry ice traps), and morphologically identified. Additionally, salivary glands DNA was extracted from 28 adult ticks infesting the animals and four nymphs from the environment, and further screened for Ehrlichia sp. and hemotropic Mycoplasma sp. Anti-T. equi and anti-Ehrlichia sp. antibodies were detected in 40.91% (nine/22; 95% CI: 23.26-61.27) and 31.81% (seven/22; 95% CI: 16.36-52.68) horses, respectively. Theileria equi, B. caballi, and hemotropic Mycoplasma sp. DNA was detected in 59.09% (13/22), 4.55% (one/22), and 50% (11/22) horses, respectively. All horses tested negative in the PCR for Ehrlichia sp. All sequences showed ≥99% identity with multiple T. equi, B. caballi, and Mycoplasma ovis sequences deposited in GenBank database. Adult ticks were identified as Dermacentor nitens (44/47; 93.62%) and Rhipicephalus microplus (three/47; 6.38%). Ticks' salivary glands were negative for Ehrlichia sp., while 39.29% from adults (11/28) and 50% from nymphs (two/four) from the environment were positive for hemotropic Mycoplasma sp. This is the first report of M. ovis infection in horses from Brazil and the first detection of hemoplasma DNA in salivary glands of D. nitens and R. microplus ticks. Further studies are needed to elucidate the vector competence of ticks to transmit hemoplasmas.
Topics: Animals; Sheep; Horses; Cattle; Babesiosis; RNA, Ribosomal, 16S; Brazil; Horse Diseases; Theileria; Mycoplasma; Ticks; Ehrlichia; Theileriasis
PubMed: 36162457
DOI: 10.1016/j.actatropica.2022.106697 -
American Journal of Human Biology : the... Sep 2021A detailed understanding of female reproductive functioning is important to many disciplines including anthropology, evolutionary theory, demography, psychology, and...
A detailed understanding of female reproductive functioning is important to many disciplines including anthropology, evolutionary theory, demography, psychology, and biomedicine. In this article, I describe strategies and methods that have been used successfully in community-based studies of human reproduction, many in remote locales, to produce high quality biomarker data. These techniques are applicable to a wide range of research questions and populations, and to persons from adolescence through senescence. I give particular attention to the inherent challenges imposed by the cyclical and somewhat unpredictable nature of the hypothalamic-pituitary-ovarian axis including the necessity and difficulty of ascertaining the timing and occurrence of ovulation, the limits of different sampling regimes for capturing fluctuations in reproductive hormones, and the critical importance of recognizing and, when possible, reducing selection bias. I discuss the relative advantages and disadvantages of collecting saliva, urine, and dried blood spots, and describe some of the subtleties involved in collecting contamination-free samples. Once samples are collected, they must be stored in a manner that minimizes degradation; I describe techniques to keep samples cold even without access to electricity or dry ice. I also discuss various issues that should be considered during initial discussions with a laboratory and when samples are assayed by the laboratory. I include examples of techniques that have worked well in actual field studies, and examples of flawed analytical approaches that should be avoided. With these and other tools, even under technology-sparse conditions, researchers can investigate variability in human physiology across the breadth of human habitats.
Topics: Anthropology; Female; Humans; Physiology; Reproduction
PubMed: 33022128
DOI: 10.1002/ajhb.23513 -
The Science of the Total Environment Oct 2022Glaciers can accumulate and release organic matter affecting the structure and function of associated terrestrial and aquatic ecosystems. We analyzed 18 ice cores...
Glaciers can accumulate and release organic matter affecting the structure and function of associated terrestrial and aquatic ecosystems. We analyzed 18 ice cores collected from six locations in Taylor Valley (McMurdo Dry Valleys), Antarctica to determine the spatial abundance and quality of organic matter, and the spatial distribution of bacterial density and community structure from the terminus of the Taylor Glacier to the coast (McMurdo Sound). Our results showed that dissolved and particulate organic carbon (DOC and POC) concentrations in the ice core samples increased from the Taylor Glacier to McMurdo Sound, a pattern also shown by bacterial cell density. Fluorescence Excitation Emission Matrices Spectroscopy (EEMs) and multivariate parallel factor (PARAFAC) modeling identified one humic-like (C1) and one protein-like (C2) component in ice cores whose fluorescent intensities all increased from the Polar Plateau to the coast. The fluorescence index showed that the bioavailability of dissolved organic matter (DOM) also decreased from the Polar Plateau to the coast. Partial least squares path modeling analysis revealed that bacterial abundance was the main positive biotic factor influencing both the quantity and quality of organic matter. Marine aerosol influenced the spatial distribution of DOC more than katabatic winds in the ice cores. Certain bacterial taxa showed significant correlations with DOC and POC concentrations. Collectively, our results show the tight connectivity among organic matter spatial distribution, bacterial abundance and meteorology in the McMurdo Dry Valley ecosystem.
Topics: Antarctic Regions; Ecosystem; Ice Cover; Spectrometry, Fluorescence; Wind
PubMed: 35697215
DOI: 10.1016/j.scitotenv.2022.156639