Chemical Preservation Research Articles

Towards chemically neutral carbon cleaning processes: plasma cleaning of Ni, Rh and Al reflective optical coatings and thin Al filters for free-electron lasers and synchrotron beamline applications

The choice of a reflective optical coating or filter material has to be adapted to the intended field of application. This is mainly determined by the required photon energy range or by the required reflection angle. Among various materials, nickel and rhodium are common materials used as reflective coatings for (soft) X-ray mirrors. Similarly, aluminium is one of the most commonly used materials for extreme ultraviolet and soft X-ray transmission filters. However, both of these types of optics are subject to carbon contamination, which can be increasingly problematic for the operation of the high-performance free-electron laser and synchrotron beamlines. As an attempt to remove this type of contamination, an inductively coupled plasma source has been used in conjunction with N2/O2/H2 and N2/H2 feedstock gas plasmas. Results from the chemical surface analysis of the above materials before and after plasma treatment using X-ray photoelectron spectroscopy are reported. It is concluded that a favorable combination of an N2/H2 plasma feedstock gas mixture leads to the best chemical surface preservation of Ni, Rh and Al while removing the carbon contamination. However, this feedstock gas mixture does not remove C contamination as rapidly as, for example, an N2/O2/H2 plasma which induces the surface formation of NiO and NiOOH in Ni and RhOOH in Rh foils. As an applied case, the successful carbon removal from ultrathin Al filters previously used at the FERMI FEL1 using an N2/H2 plasma is demonstrated.

A dual choline/phosphocholine colorimetric method for measuring the relative strength of inhibitors of choline kinases of Gram-positive pathogens

Using chemical and artificial preservation methods to keep food safe is becoming an issue with consumers. Therefore, it is important to discover antimicrobials from natural sources for use in food safety applications. The objective of the present study was to establish screening system for natural inhibitors of choline kinase (ChoK), a known antimicrobial target. A previously developed dual choline/phosphocholine colorimetric method was used to determine the relative strength of 3 choline kinase inhibitors: Hemocholinium-3, RSM-928A, and MN58 . Whole cell extracts containing the choline kinase of Streptococcus pneumoniae (sChoK) was used as a model. The measured IC50 values of these drugs were >2700 µM, 0.54 µM, and 170-225 µM, respectively. Importantly, not every step of the colorimetric method could be used in the case of every inhibitor, since each had its own particular reactive profile with the colorimetric dyes, which could have lead to confounded measurements. However, in every case, the system was flexible enough to measure choline or phosphocholine, if not both metabolites. We establish here that this dual choline/phosphocholine system is flexible enough to measure the IC50 any possible inhibitor. This colorimetric method is an ideal benchtop method for screening for natural inhibitors of bacterial ChoKs.

Effect of multi‐frequency ultrasound surface washing treatments on Escherichia coli inactivation and some quality characteristics of non‐heading Chinese cabbage

The effect of ultrasound washing with different frequencies including sweeping, fixed and combined fixed frequencies on Escherichia coli inactivation and selected physical and chemical qualities of Chinese cabbage were investigated. Colour, microstructure, total chlorophyll, total carotenes, total phenolic content, DPPH radical scavenging, hydroxyl radical scavenging and reducing power activities were measured using standard in vitro assays. In contrast with water washed samples, ultrasound washing with a fixed frequency of 40 kHz resulted in >3 log CFU/g reduction in E. coli counts, approximately 20% improvement in total phenolic content and over 32% increase in reducing power activity. There was, however, a marginal improvement in DPPH radical scavenging activity and a decrease in hydroxyl radical scavenging activity. Scanning electron micrographs revealed the presence of micro-fractures and minute holes and dislodging of surface particles Ultrasound washing improved the perceptible visual colour (∆E) and the greenish appearance of the leaves. Practical applications Multi-frequency power ultrasound washing of fresh produce is a recent application of varying frequencies in decontamination of fresh produce. The remarkable influence of ultrasonic frequency aside other operating parameters in the removal of contaminants on fruits and vegetable surfaces influenced this study. The results reported in this experimental study may be considered for application in the inactivation of microorganisms including E. coli and other Gram-negative bacteria. This washing technique may also be used in combination with other studied physical or chemical preservation methods as a synergy to enhance microbial removal and quality characteristics of fresh produce in the food industry.

A Comparative Analysis of Microbial DNA Preparation Methods for Use With Massive and Branching Coral Growth Forms.

In the last two decades, over 100 studies have investigated the structure of the coral microbiome. However, as yet there are no standardized methods applied to sample preservation and preparation, with different studies using distinct methods. There have also been several comparisons made of microbiome data generated across different studies, which have not addressed the influence of the methodology employed over each of the microbiome datasets. Here, we assess three different preservation methods; salt saturated dimethyl sulfoxide (DMSO) – EDTA, snap freezing with liquid nitrogen and 4% paraformaldehyde solution, and two different preparation methodologies; bead beating and crushing, that have been applied to study the coral microbiome. We compare the resultant bacterial assemblage data for two coral growth forms, the massive coral Goniastrea edwardsi and the branching coral Isopora palifera. We show that microbiome datasets generated from differing preservation and processing protocols are comparable in composition (presence/absence). Significant discrepancies between preservation and homogenization methods are observed in structure (relative abundance), and in the occurrence and dominance of taxa, with rare (low abundance and low occurrence) phylotypes being the most variable fraction of the microbial community. Finally, we provide evidence to support chemical preservation with DMSO as effective as snap freezing samples for generating reliable and robust microbiome datasets. In conclusion, we recommend where possible a standardized preservation and extraction method be taken up by the field to provide the best possible practices for detailed assessments of symbiotic and conserved bacterial associations.

Chondrogenic response in presence of cartilage extracellular matrix nanoparticles.

Current studies based on regenerative medicine suggest, decellularized extracellular matrix (DC-ECM) components can regulate cell phenotype. In this regard, it is believed, presence of cartilage extracellular matrix particles in culture condition could produce physical and biochemical supportive cues for chondrogenesis. In this study, DC-ECM nanoparticles with average size of 61.5± 22.4 nm were produced by decellularization and mechanical processing. Homogenous distribution and nanoscale size of yield particles were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopy imaging. Chemical structure preservation of cartilage ECM after decellularization was also confirmed by typical Fourier transform infrared (FTIR) spectrum mapping. The influence these nanoparticles on chondrogenic response of chondrocyte cells was investigated by direct and indirect addition of nanoparticles to culture medium. A clinical devitalized cartilage powder (DV-ECM) was also used as a positive control. Totally, MTS results showed that direct and indirect presence of both DC-ECM and DV-ECM particles in culture medium enhanced cellular metabolic activity except on day one of culture. Furthermore, on day 21, SOX9 and COL2 expression of cultured chondrocytes in the medium containing DC-ECM nanoparticles were up-regulated in comparison to negative control, which was further confirmed by presence more frequent number of larger size lacunae in micromass spheroids. Our findings support the use of ECM nanoparticles as condition supplement in culture medium and injectable biomaterials, especially for cell-based therapies for cartilage regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2463-2471, 2018.

Longitudinal study of rat volar fat pad fixation and ethanol storage: implications for the use of fluid-preserved specimens in morphological studies.

Museum fluid collections preserve important biological specimens for study. Tissues are often fixed in 10% buffered formalin to halt metabolic activities and transferred to a solution of ethanol for long-term storage. This process, however, forces water from the tissues and has been shown to alter the morphology of preserved specimens in ways that may influence the biological interpretation of results. The degree to which fluid preservation alters morphology is linked to multiple biological factors, such as tissue size and composition, and should therefore be examined prior to functional analysis. This study is undertaken as part of a more inclusive examination of mammalian volar morphology. A sample of five adult male and five adult female rats (Rattus norvegicus) was utilized to evaluate longitudinal changes in the dimensions of the volar pads across fixation in 10% buffered formalin and preservation in 70% ethanol for 1 year. No significant changes to the measured dimensions of the rat volar pads were present across stages of fixation and preservation, and no significant interactions of specimen size or sex were noted. These findings indicate that small mammalian volar pads that have been fixed in 10% buffered formalin and stored in 70% ethanol are appropriate for morphological study using the measurements described here without corrective algorithms. This finding is rare among preservation studies but highlights the variability of tissue behavior during chemical preservation and the necessity of preliminary investigations of preservation artifacts. Concurrence here between the preserved and unpreserved samples is likely related to the anhydrous nature of the volar pads and the supporting skeletal structure, and their confined position between major joints of the hands and feet.

STUDI PENGAWETAN LARUTAN ENZIM BROMELIN KASAR SECARA FILTRASI DAN PENAMBAHAN NATRIUM BENZOAT

(Ananas comosus (L) Merr) is a plant that contains enzyme bromelin in the fruit, leaf and skin but more in the stem. In general, enzymes are produced and marketed in powder form. However, producing enzymes in powder form requires high process technology and very expensive cost. The purpose of this research were to know how to prepare bromelin enzyme in liquid form and it preservation technique, and to know the quality of bromelin enzyme during storage. This research was conducted through 3 stages: 1. Extraction of bromelin from pineapple stem, 2. Physical and Chemical preservation and 3. Observation of enzyme storage. The results of the study showed that preservation of enzyme bromelin physically and chemically still performed enzyme activity on day 32, while enzyme without preservation did not show activity at day 24. Bromelin enzyme with physical preservation was better than chemical preservation.

Development of apple chips technology

For develop of apple chips technology without chemical preservation osmotic dehydration in cherry or apple juice concentrates or fructooligosaccharide solutions and convection drying were used. Studies included the effect of dehydration on the mass transfer in apples and the quality of the final product. The temperature, type of osmotic solution and its concentration were changeable. The fruit were tested on mass transfer indicators, stability (water activity), texture (breaking test) and nutritional value (polyphenol content, acidity). Sensory evaluation was also performed. On this basis, the verification of all options was made and the most acceptable samples were selected. Concentration of osmotic solutions at 25°Brix limited solids gain in apples. Under these conditions, the phenomenon of osmosis caused 8–10 times greater water loss than solids gain. Increasing the concentration of solutions up to 50°Brix had a significantly greater impact on mass exchange in apples, compared to increasing the temperature from 40 to 60 °C. Osmotic dehydration before drying did not significantly affect the water activity but increase of the temperature negatively affected on breaking force of the chips. Chips obtained by osmotic dehydration of apples in a cherry concentrate solution contained significantly more polyphenols, and were characterized by a higher acidity than the variants obtained by dehydration in concentrated apple juice. Furthermore, they were marked by red color which has been thought as part of the attractiveness of the product. The least sensory acceptable chips were prepared using osmotic pre-treatment in cherry concentrated juice solution with the addition of fructooligosaccharide.

Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: a chemometric approach

AbstractSpinicaudatans (‘clam shrimps’) are small branchiopod crustaceans enclosed in a chitinous bivalved carapace that is often the only preserved element in the fossil record. However, few studies have analyzed the preservation of these carapaces, which have been found in continental facies from the Devonian to the present. The aim of this study was to contribute to a better understanding of the chemical preservation of fossil spinicaudatan carapaces, and it focused on spinicaudatan carapaces of the Cañadón Asfalto Formation from the Jurassic of Argentina. Semiquantitative energy-dispersive X-ray spectrometry (EDS) analysis provided elemental composition data that were interpreted using principal component analysis (PCA). The results showed a complex chemical mode of preservation for spinicaudatan carapaces. In some parts, EDS spectra of the specimens exhibit peaks of calcium, phosphorous, aluminum, and fluorine, representing the retention of original carapace material with some diagenetic recrystallization. Certain zones of the carapace show low-intensity peaks of the elements mentioned, while silicon and oxygen peaks (from the rock matrix) become the dominant spectral signals. These modes of preservation modify the interpretations and observations of the ornamentation of the carapace, which are used as taxonomic features. Our results suggest that specific diagenetic processes play a fundamental role in the preservation of spinicaudatans.

Effect of NaOH-EDTA extraction time on the degradation of phosphate compounds

A chemical extraction of soil organic- and poly‑phosphorus (P) with a 0.25 M NaOH +0.05 M ethylenediaminetetraacetic acid (EDTA) solution is the most widely accepted method for 31P NMR measurements. The chemical preservation is often questioned because of inconsistent extraction time (4–16 h) among researchers. In this study, the effect of extraction time on the degradation of common P compounds (phytic acid, pyrophosphate, 2-aminoethylphosphonic acid, adenosine 5′-triphosphate disodium, and tripolyphosphate) was investigated using a spectrophotometric method. No degradation was observed up to 16 h in most of the compounds except for tripolyphosphate. The hydrolytic degradation of tripolyphosphate was retarded initially due to a high ionic strength of the extractant but became apparent after 8 h.

Chemical Preservation of Semi-volatile Polycyclic Aromatic Hydrocarbon Compounds at Ambient Temperature: A Sediment Sample Holding Time Study.

Site investigations require the collection and analysis of representative environmental samples to delineate impacts, risks, and remediation options. When environmental samples are collected, concentrations of semi-volatile polycyclic aromatic hydrocarbons (PAHs) begin to change due to several processes, such as evaporation, adsorption, precipitation, photo, and microbial degradation. Preservation techniques are used to minimize these changes between collection and analysis. The most common techniques are refrigeration, freezing, and acidification. In the mid 1970s, regulatory agencies developed a holding time limit of 14days for PAHs in soil/sediment samples stored at < 6°C. The technical basis for this limit is not well defined yet failing to meet this limit may force resampling. This study examined the effectiveness of preservatives at maintaining PAH concentrations in sediment samples to 60days. Sediment samples were collected at three sites that were impacted with petrogenic and pyrogenic PAHs. Chemically preserved (sodium azide, NaN3) and unpreserved samples were analyzed at defined time intervals from 0 to 60days. Statistical analysis indicated acceptable preservation of PAHs in the sediment samples preserved with sodium azide for 60days when maintained at either ambient laboratory temperature or 4 ± 2°C, and for up to 21days with no preservative when maintained at 4 ± 2°C.

Effect of ultrasound and chemical treatment on total phenol, flavonoids and antioxidant properties on carrot-grape juice blend during storage

Ultrasonics is one of the developing technologies which is being studied extensively on different food commodities. Our aim was to study the effect of sonication and chemical (Potassium metabisulfite, K2S2O5,) preservation method on grape-carrot juice blend. Sonication/ultrasound treatments (20 kHz frequency, 70% amplitude level (525 W power), and pulse duration 5 s on and 5 s off, 5 min at 15 °C) of all the samples (250 mL) were performed by using an ultrasonic processor with 0.5 in. probe at 2 in. depth of the sample. Additionally, impact of sonication on 90 days of storage period at refrigerated temperature was also measured. It was observed that sonication had a positive effect on nutritional status of juice blend as it enhanced the total phenolic, flavonoid, reducing power and antioxidant properties of juice significantly (p < 0.05) with increase in sonication time. Sonication can be employed successfully for treatment of juice with better nutritional attributes from consumers’ point of view.

Degradation of inhibitor in alkaline cleaning solution for post-Cu CMP cleaning

In this current work, the degradation of the commercial alkaline cleaning solution for post-Cu chemical mechanical planarization (CMP) cleaning process was systemically investigated. According to the results of electrochemical measurements and X-ray photoelectron spectroscopy, the degradation of the commercial alkaline cleaning solution originated from the oxidation of the commercial amino-group corrosion inhibitor in it, thus resulting in the formation of CuO film from native Cu2O film. Eventually, we proposed that the commercial alkaline cleaning solution should be sealed in an inert-gas blanket during chemical drum preservation to avoid oxygen exposure in the atmosphere, and therefore the production of the scratch defects due to the formed CuO layer was significantly reduced.

Discovering the Chemical Elements in Food

The educational possibilities of combining four powerful teaching strategies (context-based teaching, inquiry-based teaching, murals, and augmented reality) in the learning of the chemical elements are reported in this paper. We present a project involving 15-year-old students who research and identify the chemical elements present in food using an inquiry-based approach. Students organize their findings in four categories according to the role of the chemical element in the food (major elements, essential trace elements, toxic trace elements, and chemical food preservation). Conclusions were disseminated through a large mural with audio QR codes where results can be explored for students using a smart phone. To investigate the effectiveness of the project we ask students to identify chemical elements in food and whether their intake was beneficial or harmful to health, before (pretest) and after (post-test) the project. In the first case, only five foods (milk products, bananas, lentils, water, and salt)...

Nanoscopic X-ray fluorescence imaging and quantification of intracellular key-elements in cryofrozen Friedreich's ataxia fibroblasts.

Synchrotron radiation based nanoscopic X-ray fluorescence (SR nano-XRF) analysis can visualize trace level elemental distribution in a fully quantitative manner within single cells. However, in-air XRF analysis requires chemical fixation modifying the cell’s chemical composition. Here, we describe first nanoscopic XRF analysis upon cryogenically frozen (-150°C) fibroblasts at the ID16A-NI ‘Nano-imaging’ end-station located at the European Synchrotron Radiation Facility (ESRF) in Grenoble (France). Fibroblast cells were obtained from skin biopsies from control and Friedreich’s ataxia (FRDA) patients. FRDA is an autosomal recessive disorder with dysregulation of iron metabolism as a key feature. By means of the X-ray Fundamental Parameter (FP) method, including absorption correction of the ice layer deposited onto the fibroblasts, background-corrected mass fraction elemental maps of P, S, Cl, K, Ca, Fe and Zn of entire cryofrozen human fibroblasts were obtained. Despite the presence of diffracting microcrystals in the vitreous ice matrix and minor sample radiation damage effects, clusters of iron-rich hot-spots with similar mass fractions were found in the cytoplasm of both control and FRDA fibroblasts. Interestingly, no significant difference in the mean iron concentration was found in the cytoplasm of FRDA fibroblasts, but a significant decrease in zinc concentration. This finding might underscore metal dysregulation, beyond iron, in cells derived from FRDA patients. In conclusion, although currently having slightly increased limits of detection (LODs) compared to non-cryogenic mode, SR based nanoscopic XRF under cryogenic sample conditions largely obliterates the debate on chemical sample preservation and provides a unique tool for trace level elemental imaging in single cells close to their native state with a superior spatial resolution of 20 nm.

Evaluation of wood properties of four ages of Cedrela odorata trees growing in agroforestry systems with Theobroma cacao in Costa Rica

The present work studies the morphological, physical, mechanical and chemical properties, decay resistance, preservation and workability of Cedrela odorata wood from trees growing in agroforestry systems with Theobroma cacao at four ages (4-, 5-, 6- and 7-years-old) in Costa Rica. It was found that the morphological properties (heartwood, pith and bark), together with the physical properties (specific gravity, green density, shrinkage and green moisture content) presented few differences at the four ages. The wood from 4-years-old trees was the only exception, showing less resistance in compression, flexion and lateral hardness. The content of lignin, carbon, and extractives in hot water were not affected among the different ages, contrary to the rest of chemical properties. In relation to decay resistance in accelerated tests with the fungus Trametes versicolor, the wood is classified as highly resistant, while with the fungus Lencites acuta it is classified as moderately resistant. As concerns properties related to industrialization, it was found that the wood can be preserved through vacuum-pressure methods obtaining similar results as those from other plantation timbers. As for workability tests, the wood from the 4-years-old trees show acceptable to very poor performance, differing from trees from the other ages.

Chemical Preservation Methods of Urine Sediment for Quality Control

요침사 검사는 물리화학적 검사보다 정도관리의 표준화가 어려운 실정이다. 본 연구에서는 요침사 정도관리의 합리성을 위해 요침사 보존제인 글루타르알데히드로 요침사를 보존하여 실물을 통한 현미경 검사로 요침사 정도관리가 가능한지를 알아보고자 하였다. 2.5% 글루타르알데히드를 보존액으로 하여 표본을 제작하였다. 보존제를 처리한 검체는 1주일 간격으로 4주간 세포의 형태학적 변형을 확인하였고, 이후 4주간은 보존여부를 확인하였다. 요침사 슬라이드 제작 후 2개의 슬라이드를 제작하였으며, 하나는 냉장보관, 다른 하나는 실온 보관하여 검체의 형태학적 변형을 확인하였다. 글루타르알데히드는 요침사를 냉장 보관하여 8주까지 보존하는 효과가 있었으며, 슬라이드 제작 후에는 냉장 보관하여 3일까지 안정한 것으로 나타났다. 또한 보존제 처리 후 슬라이드 제작하여 검사실간, 검사자간판독을 비교한 결과 낮은 일치도를 보였다. 결론적으로 본 연구를 통해 요침사 성분을 보존할 수 있으며, 실물을 통한 정도관리 및 교육용으로 활용될 것으로 기대된다.

Chemical alteration and preservation of sedimentary/organic nitrogen isotope signatures in a 2.7 Ga seafloor volcanic sequence

AbstractMassive to lobate volcanic flows and brecciated hyaloclastite units in the Abitibi greenstone belt allow investigation of Late Archæan seafloor alteration and associated incorporation into these rocks of nitrogen (N) biogeochemical signatures. In this suite (the Blake River Group), hyaloclastite units containing putative microbial ichnofossils are particularly enriched in large-ion lithophile elements (K, Rb, Ba, Cs), B, and Li, consistent with their having experienced the greatest fluid–rock interaction during subseafloor hydrothermal alteration. Similarly, silicate-δ18O and δ15N values for samples from the hyaloclastites show the greatest shifts from plausible magmatic values. The chemical and isotopic patterns in these tholeiitic igneous rocks greatly resemble those in modern altered seafloor basalts, consistent with the preservation of an Archæan seafloor alteration signature. The N enrichments and shifts in δ15N appear to reflect stabilization of illite and interaction with fluids carrying sedimentary/organic signatures. Enrichments of N (and the δ15N of this N) in altered glass volcanic rocks on Earth's modern and ancient seafloor point to the potential utility of N for tracing past and present biogeochemical processes in similar rocks at/near the Mars surface.

Antifungal Microbial Agents for Food Biopreservation-A Review.

Food spoilage is a major issue for the food industry, leading to food waste, substantial economic losses for manufacturers and consumers, and a negative impact on brand names. Among causes, fungal contamination can be encountered at various stages of the food chain (e.g., post-harvest, during processing or storage). Fungal development leads to food sensory defects varying from visual deterioration to noticeable odor, flavor, or texture changes but can also have negative health impacts via mycotoxin production by some molds. In order to avoid microbial spoilage and thus extend product shelf life, different treatments—including fungicides and chemical preservatives—are used. In parallel, public authorities encourage the food industry to limit the use of these chemical compounds and develop natural methods for food preservation. This is accompanied by a strong societal demand for ‘clean label’ food products, as consumers are looking for more natural, less severely processed and safer products. In this context, microbial agents corresponding to bioprotective cultures, fermentates, culture-free supernatant or purified molecules, exhibiting antifungal activities represent a growing interest as an alternative to chemical preservation. This review presents the main fungal spoilers encountered in food products, the antifungal microorganisms tested for food bioprotection, and their mechanisms of action. A focus is made in particular on the recent in situ studies and the constraints associated with the use of antifungal microbial agents for food biopreservation.

Identification and Quantification of Sodium Benzoate in Different Brands of Mango Juices Available in Tangail Region, Bangladesh

Chemical preservation has become an increasingly important practice in modern food technology. Sodium benzoate is a permitted food additive in restrictive amounts by international laws, but their content must be declared and must not exceed the established limits by legislation. An experimental study for the level of sodium benzoate in different brands of mango juices available in the markets, stores and shops in Tangail region of Bangladesh was determined by high performance liquid chromatography. A Luna 5 ? C18 (2) 100A column (250 × 4.6 mm) was used for the chromatographic analysis. Chromatographic separation was achieved with isocratic solvent system comprising of sodium acetate and acetic acid buffer (pH =4.0)/acetonitrile in the ratio of 80:20 (1 ml/min) at 37oC and the chromatograms were recorded at 254 nm. The limit of detection and quantification for sodium benzoate was 0.00076 mg/100 ml and 0.00231 mg/100 ml, respectively. Quantification of the selected brand juices revealed that the level of the used sodium benzoate was within the FDA standard range. But by comparing with the Bangladesh Standard and Testing Institute (BSTI), brand-1 and brand-3 of the analyzed juice samples was found to deviate the current legal limits. The percentage recovery was found to be 92.04 ± 1.98 to 98.01 ± 1.91. It was found that some of the brands used excess amount of sodium benzoate which may be harmful for our health.Bangladesh Pharmaceutical Journal 20(1): 20-26, 2017