Extended Storage Period Research Articles

Proper period and temperature for transportation of cucumber and tomato transplants

With an increased demand for high-quality transplants, vegetable growers have begun to purchase grafted transplants from specialized propagators. These are often shipped over long distances, but improper transport conditions can deteriorate transplant quality. To determine the appropriate period and temperature for transporting grafted transplants, we stored cucumber and tomato transplants in darkness at 6, 9, 12, 15, and 18 o C for 3, 6, 9, 12, and 15 days, and subsequently cultivated these in a greenhouse for 15 days. We investigated the changes in plant height and SPAD value during storage, as well as the early growth of the stored transplants during subsequent cultivation. Increasing temperature during storage promoted stem elongation in both transplant species, with cucumber transplants showing greater stem elongation than tomato transplants. SPAD values of cucumber and tomato transplants tended to decrease with increasing storage temperature, declining even further with extended storage period. The cucumber transplants stored for 3 days and the tomato transplants stored for 6 days, showed no decrease in percent survival and no delay of growth after transplanting compared with non-stored transplants. From these results, we suggest that the appropriate temperature for transporting cucumber and tomato transplants in darkness is 6°C, and the appropriate period of storage in darkness are 3 and 6 days for cucumber and tomato transplants, respectively. Controlling transportation conditions can avoid the deterioration of transplant quality during transport and the delay of early growth after transplanting.

Integrity of the Human Faecal Microbiota following Long-Term Sample Storage.

In studies of the human microbiome, faecal samples are frequently used as a non-invasive proxy for the study of the intestinal microbiota. To obtain reliable insights, the need for bacterial DNA of high quality and integrity following appropriate faecal sample collection and preservation steps is paramount. In a study of dietary mineral balance in the context of type 2 diabetes (T2D), faecal samples were collected from healthy and T2D individuals throughout a 13-day residential trial. These samples were freeze-dried, then stored mostly at -20°C from the trial date in 2000/2001 until the current research in 2014. Given the relative antiquity of these samples (~14 years), we sought to evaluate DNA quality and comparability to freshly collected human faecal samples. Following the extraction of bacterial DNA, gel electrophoresis indicated that our DNA extracts were more sheared than extracts made from freshly collected faecal samples, but still of sufficiently high molecular weight to support amplicon-based studies. Likewise, spectrophotometric assessment of extracts revealed that they were of high quality and quantity. A subset of bacterial 16S rRNA gene amplicons were sequenced using Illumina MiSeq and compared against publicly available sequence data representing a similar cohort analysed by the American Gut Project (AGP). Notably, our bacterial community profiles were highly consistent with those from the AGP data. Our results suggest that when faecal specimens are stored appropriately, the microbial profiles are preserved and robust to extended storage periods.

Estimation of Inherent Safety Margins in Loaded Commercial Spent Nuclear Fuel Casks

A novel assessment has been completed to determine the unquantified and uncredited safety margins (i.e., the difference between the licensing-basis and as-loaded calculations) available in as-loaded spent nuclear fuel (SNF) casks. This assessment was performed as part of a broader effort to assess issues and uncertainties related to the continued safety of casks during extended storage and transportability following extended storage periods. Detailed analyses crediting the actual as-loaded cask inventory were performed for each of the casks at three decommissioned pressurized water reactor sites to determine their characteristics relative to regulatory safety criteria for criticality, thermal, and shielding performance. These detailed analyses were performed in an automated fashion by employing a comprehensive and integrated data and analysis tool—Used Nuclear Fuel-Storage, Transportation and Disposal Analysis Resource and Data System (UNF-ST&DARDS). Calculated uncredited criticality margins from 0.07 to almost 0.30 Δkeff were observed, calculated decay heat margins ranged from 4 to almost 22 kW (as of 2014), and significant uncredited transportation dose rate margins were also observed. The results demonstrate that at least for the casks analyzed here, significant uncredited safety margins are available that could potentially be used to compensate for SNF assembly and canister structural performance related uncertainties associated with long-term storage and subsequent transportation. The results also suggest that these inherent margins associated with how casks are loaded could support future changes in cask licensing to directly or indirectly credit the margins. Work continues to quantify the uncredited safety margins in the SNF casks loaded at other nuclear reactor sites.

PHYSICOCHEMICAL AND MICROBIOLOGICAL CHARACTERISTICS OF THE WASTE DUMPS AFTER COAL ENRICHMENT

Aim. The physical-chemical and microbiological characteristics of technogenic substrates depending on the duration of their storage have been studied. Methods. Atomic emission and atomic absorption spectroscopy, potentiometric method and the author’s patented electrochemical cell, standard microbiological method of cumulative cultures. Results. It was established, that during long storage of waste dumps there occurs the components concentration and oxidation of metal ions, that were found in the waste dumps, to the highest degree of oxidation and were formed more stable equilibrium structures. The effect of indigenous microbiota of waste dumps to increase their resistance to the processing has been shown. As it has been shown the indigenous microbiota of waste dumps are facilitated of increase their resistance to the recycling. The cumulative culture of microorganisms of different physiological groups forming microbiocenosis of waste dumps were obtained and quantified. The quantitative predominance of representatives of major groups of chemolithotrophic acidophilus bacteria (both mesophilic and moderately thermophilic) of indigenous microbiota from waste dumps with extended storage period, has been established. That, in turn, leads to a more pronounced effect of microbiota on the physicochemical characteristics of these waste dumps. Conclusion. The physical, chemical and microbiological changes are significant in storage dumps composition in the process of their accumulation. This should be taken into account in selecting the conditions of utilization of technogenic substrates by biotechnological methods using active members of their own microbiota.

Effect of gamma irradiation and extended storage on selected chemical constituents and antioxidant activities of sliced mushroom

Due to its exquisite odor and taste, Boletus edulis Bull.: Fr. mushroom is being increasingly used throughout the world. However, the availability of this product is highly restrained by its seasonality and perishability, demanding special care to keep its quality. Furthermore, mushrooms are often distributed in sliced form, and the slicing operation requires special treatments, besides augmenting the possibility of microbial contamination. Some techniques are currently applied to sliced mushrooms, but these processes had adverse effects on nutrients, odor, texture and taste, besides requiring expensive equipment. Food irradiation is being studied as an alternative technology to improve the quality and durability of determined products, having been previously applied in several mushroom species. Herein, gamma irradiation was applied to dried and sliced samples of B. edulis, at high doses (2, 6 and 10 kGy), and the effects on nutritional, chemical and antioxidant parameters were evaluated throughout storage (6 and 12 months). The results obtained for the chemical parameters do not advised storing B. edulis for such extended periods, since some relevant changes were detected, especially in samples stored for 12 months. In general, the gamma irradiation treatment did not cause further changes in the chemical composition, besides having a slightly positive effect in keeping the antioxidant activity and most of the bioactive compounds profiled in this work, contributing to maintain the potential health effects of this exquisite food, even after extended storage periods.

Anaerobic Biodegradation of Alternative Fuels and Associated Biocorrosion of Carbon Steel in Marine Environments.

Fuels that biodegrade too easily can exacerbate through-wall pitting corrosion of pipelines and tanks and result in unintentional environmental releases. We tested the biological stability of two emerging naval biofuels (camelina-JP5 and Fischer-Tropsch-F76) and their potential to exacerbate carbon steel corrosion in seawater incubations with and without a hydrocarbon-degrading sulfate-reducing bacterium. The inclusion of sediment or the positive control bacterium in the incubations stimulated a similar pattern of sulfate reduction with different inocula. However, the highest rates of sulfate reduction were found in incubations amended with camelina-JP5 [(57.2 ± 2.2)-(80.8 ± 8.1) μM/day] or its blend with petroleum-JP5 (76.7 ± 2.4 μM/day). The detection of a suite of metabolites only in the fuel-amended incubations confirmed that alkylated benzene hydrocarbons were metabolized via known anaerobic mechanisms. Most importantly, general (r(2) = 0.73) and pitting (r(2) = 0.69) corrosion were positively correlated with sulfate loss in the incubations. Thus, the anaerobic biodegradation of labile fuel components coupled with sulfate respiration greatly contributed to the biocorrosion of carbon steel. While all fuels were susceptible to anaerobic metabolism, special attention should be given to camelina-JP5 biofuel due to its relatively rapid biodegradation. We recommend that this biofuel be used with caution and that whenever possible extended storage periods should be avoided.

Tree and cold storage influence on incidence of albedo breakdown, textural properties of the rind and fruit quality in ‘Washington Navel’ orange

Introduction . Albedo breakdown (AB) causes serious economic losses to sweet orange growers. The growers practice delayed harvesting (tree storage) to extend the fresh fruit supply to market. We investigated the effects of tree storage and cold storage on AB incidence, textural properties of the rind and fruit quality. Materials and methods. Fruit of ‘Washington Navel’ orange were harvested at the commercial maturity stage (3rd July) and then 31, 62 and 93 days after the harvest. The AB incidence, textural properties of the rind and fruit quality were assessed in one lot of fruit after harvest and a second lot after 31, 62 and 93 days of cold storage (5 °C). Results and discussion. The AB incidence increased from 65% to 89% from the first to the last harvest, respectively. Extended storage periods reduced rind hardness and fruit firmness, and increased the rind tensile force irrespective of the storage type. The rind hardness, tensile force and fruit firmness were higher in cold-stored fruit than fruit stored for 93 days on the tree. The soluble solids concentration: titratable acidity (SSC:TA) ratio in juice increased with the extended storage period in both types of storage. The increase in SSC:TA was more pronounced at 62 and 93 days in cold-stored than tree-stored fruit. The concentrations of fructose and glucose in the juice of fruit stored on the tree for 93 days were higher than in the cold-stored fruit, and sucrose showed the reverse trend. Conclusion. The cold-stored fruit exhibited a higher rind hardness, rind tensile force, firmness and SCC:TA ratio, lower concentrations of citric acid, malic acid, fructose and glucose, and lower AB incidence than the tree-stored fruit. These findings indicate a preference for cold storage over tree storage for the orange fruit quality.

Inventory and pricing model with price-dependent demand, time-varying holding cost, and quantity discounts

In typical EOQ-based inventory models, the demand rate and the holding cost are assumed to have constant values and the unit purchase cost is assumed constant regardless of the order size. In actual applications, however, the demand rate for a specific item can be affected by many variables such as seasonality, selling price, and availability. Moreover, the unit holding cost tends to be higher for extended storage periods. Additionally, the unit purchase cost is generally lower for larger order sizes due to quantity discounts. The objective of this paper is to simultaneously consider the variability of the demand rate, the unit holding cost, and the unit purchase cost. An inventory model is presented with a selling price-dependent demand rate, a storage time-dependent holding cost, and an order size-dependent purchase cost based on all-units quantity discount. A mathematical model is constructed, and a solution methodology is developed for determining the optimal solution. A numerical example is solved, and sensitivity analysis is conducted to study the effect of various parameters on the optimal solution.

Assessment of quality of platelets preserved in plasma and platelet additive solution: A Malaysian experience.

Background:A use of platelet additives solution (PAS) improves storage conditions so as to give increased shelf life to platelets and to maintain hemostatic function.Objective:The present study was aimed to compare in vitro quality of platelet rich plasma (PRP)-derived platelet concentrate (PC) during extended period of storage in plasma and in additive solution (Composol PS and Fresenius).Study Design:Randomized 19 PCs each were used in the study for plasma and PAS as the storage medium. The measurement parameters, including pH, total white blood cell (WBC) count, total platelet count, and platelet activation rate, were studied on day 1, day 5, and day 8 of the storage period. The sterility test was carried out on the eighth day of storage.Results:pH of PC suspended in PAS was significantly lower as compared to that in plasma (P < 0.001) for all the three days of sampling. The WBC count, both in plasma and in PAS, showed an acceptable values of being <0.2 Χ 109 /unit during the storage period. Platelet count in PAS was higher as compared to that in plasma, though it was not statistically significant. While both the groups showed increased platelet activation rate during the storage, the PCs suspended in PAS showed significantly higher platelet activation rate (p0.001). Results from sterility test showed no bacterial growth in the PCs in both the groups.Conclusion:Most parameters studied on platelet storage in suspending medium of native plasma and PAS remained well within the acceptable limits. However, the pH values and platelet activation rate significantly differed in PAS as compared with plasma.

Simultaneous analysis of mono-, di-, and tri-ethanolamine in cosmetic products using liquid chromatography coupled tandem mass spectrometry.

Alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) are used as wetting agents in shampoos, lotions, creams, and other cosmetics. DEA is widely used to provide lather in shampoos and maintain a favorable consistency in lotions and creams. Although DEA is not harmful, it may react with other ingredients in the cosmetic formula after extended storage periods to form an extremely potent carcinogen called nitrosodiethanolamine (NDEA), which is readily absorbed through the skin and has been linked to the development of stomach, esophagus, liver, and bladder cancers. The purpose of this study was to develop a simultaneous quantification method for measurement of MEA, DEA, and TEA in cosmetic products. Liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) was performed using a hydrophilic interaction liquid chromatography (HILIC) column with isocratic elution containing acetonitrile and 5mM ammonium formate in water (88:12, v/v). Identification and quantification of alkanolamines were performed using MS/MS monitoring to assess the transition from precursor to product ion of MEA (m/z, 61.1→44.0), DEA (m/z, 106.1→88.0), TEA (m/z, 150.1→130.0), and the internal standard triethylamine (m/z, 102.2→58.0). Alkanolamines extractions were simplified using a single extraction with acetonitrile in the cosmetic matrix. Performance of the method was evaluated with quality parameters such as specificity, carry-over, linearity and calibration, correlation of determination (R(2)), detection limit, precision, accuracy, and recovery. Calibration curves of MEA (2.9-1000ppb), DEA (1-1000ppb), and TEA (1-1000ppb) were constructed by plotting concentration versus peak-area ratio (analyte/internal standard with a correlation coefficient greater than 0.99). The intra- and inter-assay accuracy ranged from 92.92 to 101.15% for all analytes. The intra- and inter-assay precision for MEA, DEA, and TEA showed all coefficients of variance were less than 9.38% for QC samples. Limits of detection and limits of quantification were 2.00 and 15.63ppb for MEA, 0.49 and 1.96ppb for DEA, and 0.49 and 1.96ppb for TEA, respectively. This novel quantification method simplified sample preparation and allowed accurate and reproducible quantification of alkanolamines in the ng/g cosmetic weight (ppb) range for several cosmetic products.

РОЗРОБКА РЕЖИМУ ФЕРМЕНТАЦІЇ БІЛКОВОЇ МАСИ У ТЕХНОЛОГІЇ БІЛКОВИХ ПАСТ ДЛЯ ДИТЯЧОГО ХАРЧУВАННЯ

Basing on the analysis of the market for baby food products in Ukraine, the paper shows the prospects of the development of innovative technologies for food protein pastes used for the nutrition of children of 8 months and upwards with high probiotic, antagonistic and hypoallergenic properties, high bioavailability and biological efficiency, and extended storage period; the prospects of three ways of implementation of the thermostat production mode of protein pastes for baby food are also defined here. The protein cream fermentation mode is grounded here in which the protein cream is enriched with lactulose, a complex of vitamins FT 041081EU and / or a complex of minerals FT 042836EU in the technology of protein pastes for baby food products with the usage of sour compounds based on bifidobacteria and lactobacilli bacterial concentrates obtained by freezing and freeze-drying with fermentation temperature of (37 ± 1) °C and duration of 5.5 hours. Being singled out are also prospects of using protein pastes for baby food products which have bacterial concentrates of high probiotic and proteolytic properties and are based on mixed cultures Lac. lactis ssp. (F DVS C-301 or F DVS C-303 ) and monocultures Bifidobacterium animalis Bb-12 (F DVS Bb-12) obtained by freezing. The paper shows the stimulating effect of complex vitamins and minerals on the growth of bifidobacteria, lactobacilli and mesophilic lactic-acid lactococci in the protein cream; defines the synergistic impact of the stimulating effect of the vitamins and minerals complexes joint use on bifidobacteria and lactobacilli growth. The organoleptical, physical, chemical and microbiological parameters of fermented protein cream are also defined and its advantages over sour-milk cheese for baby food produced by dairy milk processing plants are singled out.

Обґрунтування складу заквашувальної композиції для виробництва йогурту функціонального призначення

Basing on the analysis of the Ukrainian functional food market, the article shows development prospects for new kinds of yoghurt with enhanced functional qualities using starter compositions of lactobacilli and bifidus bacteria consortium in the formula. It grounds the choice of lactobacilli bacterial concentrates («GoodFood») and probiotic cultures B. longum and E. faecium («Bifiform») of direct application for starter composition development in functional yoghurts production. The article studies organoleptic, physicochemical and microbiological characteristics of curds produced from milk formula fermentation using mixture of bacterial concentrates «GoodFood» and «Bifiform». It also shows the potential of lactobacilli and bifidus bacteria combination found in the above mentioned bacterial concentrates and in starter compositions for functional yoghurts production. It also shows the necessity for enrichment of the milk formula with fructose as a bifidogenic factor.The article grounds the starter composition formula for functional yoghurts production which has consortium of cultures Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueski subsp. bulgaricus, Lactobacillus acidophillus, Enterococcus faecium and Bifidobacterium longum of 1:1:1:1 ratio with initial concentration of all the cultures in the milk formula of 1·106 CFU/cm3. It defines organoleptic, physicochemical and microbiological characteristics of fermented curds produced by using of recommended lactobacilli and bifidus bacteria starter composition and shows that these curds may be the base for production of functional yoghurts with extended storage period.

The Influence on Storage Quality of Pleurotus Eryngii by 1-Methylcyclopropene Treatment

The paper is concerned with 1-MCP effect on post-harvest Pleurotus eryngii weight loss rate, polyphenol oxidase (PPO) activity and fruit body microstructure at different storage stage.The results showed that compared with control group, the weight loss rate and PPO activity were decreased by 5.94% and 37.38% ,and its microstructure had least change after 14d when treated with 0.3µL/L 1-MCP.The weight loss rate and PPO activity also decreased by 5.42% and 33.98% respectively with least change in fruit body microstructure after 14d when treated with 1-MCP for 24h. It proved that the optimal 1-MCP processing concentration is 0.3µL/L and the most appropriate processing time is 24h. These processing conditions slowed down the weight loss rate and browning level ,also reduced the change of fruit bodies microstructure and extended storage period

Effect of Modified Atmosphere Packaging on Postharvest Quality of Kohlrabi

Abstract: The effect of modified atmosphere packaging (MAP) on kohlrabi (Brassica olerace L. gongulodes group)’s quality and antioxidant molecule during storage was examined to determine the optimal film package for maintaining freshness. To extend shelf life, MAP was tested using PE 50 μm and oriented polypropylene (OPP) films with oxygen transmission rate (OTR) at 3,000, 10,000, 15,000 mL/m 2 /day/atm. The OPP film packaging with modified oxygen transmission rate showed a delay in a weight loss and extended storage period. The package with OTR 3000 attained the desired gas composition of O 2 3.2-6.7 kPa and CO 2 13.1-19.8 kPa, in storage at room temperature. Kohlrabi stored in this package showed the lowest weight loss and the highest visual quality. Deterioration and off-odor were developed more rapidly in PE 50 μm towards the end of the storage at room temperature. However, there are no differences among OTR films in visual quality and off-odor until 60 days at cold storage. Vitamin C content of kohlrabi was reduced rapidly in OTR 15000 with high transmission rate and showed less loss in PE 50 μm and OTR 3000 in both room temperatures and cold storage. Results revealed that an OPP film with OTR 3000 extended the shelf life of kohlrabi in storage with maintained quality and vitamin C.Additional key words:

Immobilization of lipase on woolen fabrics: Enhanced effectiveness in stain removal

The aim of this research was to examine the effectiveness of an enzyme in enhancing the cleaning effectiveness of woolen fabric without addition of any detergent. As a model enzyme, lipase from Pseudomonas fluoresces was immobilized onto a woolen cloth using a unique protocol that involved: chlorination of the wool, adsorbing a polyethyleneimine (PEI) spacer, adsorbing, and cross-linking with glutaraldehyde (GA) followed by adsorption of the lipase. It was determined that for this protocol, the immobilized activity was dependent on the GA solution pH and not on its concentration. The cloth exhibited excellent oily stain removal ability: after being stained with olive oil and stored for 1 day in air at room temperature, the oily stain could be easily removed by 0.05 M pH 8.5 Tris buffer without any detergent addition. This enhanced cleaning was stable also over a period of one month. The activity of the cloth (based on activity assay) dropped considerably over just 15 days storage in air. This therefore likely indicates that the enhanced cleaning seen over an extended storage period may not require as high an enzyme activity. The activity of the immobilized lipase was also very stable when stored under near ideal conditions: when the immobilized cloth was stored in 0.05 M Tris buffer (pH 8.5) for more than 80 days in a refrigerator, more than 80% of the lipase activity remained. Overall, results indicate that this immobilization protocol is a promising step towards producing a woolen fabric with enhanced cleaning properties.

Effects of extended period of storage and strain of layer on quality of chicken eggs

Poultry farmers in Ghana use different strains of layers for egg production with eggs produced being stored for some time before use. This has necessitated a study to determine the effect of strain of layers and extended storage length on internal and external qualities of chicken eggs. A total of three-hundred (300) eggs from 46-week old layer strains were analysed for egg quality in a 3 X 5 factorial experiment involving three layer strains (Lohmann brown, Lohmann white and Black Bovan) and 5 storage periods of 0, 5, 10, 15 and 20 days. On each day of the analysis, sixty (60) eggs; 20 each from the three strains were randomly sampled and analysed for the internal and external egg characteristics. Results obtained showed a significant difference (P&lt;0.05) among the three layer strains regarding the major egg quality traits like egg weight, albumen weight, haugh unit and yolk weight with the Black Bovan layer strains being superior to the Lohmann strains. It was also observed that the major egg quality traits like egg weight, albumen weight and haugh unit were significantly (P&lt;0.05) affected with increasing storage length. There was also a significant (P&lt;0.05) interaction effects between strain of layer and length of storage of egg on some important egg quality determinants like egg weight, albumen height and haugh unit. This shows that in order not to compromise the quality of eggs, one must consider the strain of layer to use and how long eggs could be stored before use. Irrespective of the strain of layers and storage period, it was realized that egg weight was more closely associated (P&lt;0.05) with albumen height and weight than the other traits.Keywords:Keywords: Albumen height, egg quality, egg weight, haugh unit, storage length, strain

Container Materials for the Storage and Disposal of Nuclear Waste

A wide range of alloys have been considered as candidate container materials for the storage and disposal of nuclear waste. The goal of the majority of national nuclear waste management programs is the ultimate disposal of the waste, although, depending upon the strategy being followed, disposal may come only after an extended period of storage. The management strategy depends on the nature of the waste, with intermediate level waste (ILW) generally being stored for a longer period before disposal than is the case for higher activity wastes, such as high-level waste (HLW) from reprocessing activities or spent fuel (SF). This review describes the corrosion issues associated with the storage and disposal of both ILW and HLW/SF. Various factors enter into the decision of which material to select for the container, of which the corrosion behavior in the expected service environment is only one. The corrosion behavior of the container material(s) is closely tied to the nature of the environment to which the co...

Effect of Modified Atmosphere Packaging (MAP) on the Quality of ‘Ready-To-Eat’ Shredded Cabbage

Shredded white cabbage (Brassica oleracea L) var Bunner were stored in modified atmosphere packaging(MAP) made of medium density polyethylene film with thickness of 30 μm. The in package gasconcentrations (O2, CO2 and C2H4), mass loss, texture, and superficial color were estimated. Browning ofthe cut surfaces, total visual quality, proliferation of the ‘pepper spot’ disorder and off-odors wereassessed organoleptically. Shredded cabbage was stored at 0oC for a period of 23 days. After 6 days ofstorage significant O2 depletion of the atmosphere was found. A sharp rise of ethylene concentration wasrecorded on the 6th day of storage due to wounding, followed by a decline. Limited mass loss (0.5% of theinitial mass) and increase in hardness were estimated due to the beneficial effect of packaging. Thelightness L* and hue angle (h*) reduction was limited at all cases and the initial color was preserved. Thevisual quality of the packaged produce was assessed by six trained panelists and it was reported thatcontrol remains marketable for 12 days, while shredded cabbage can be packed in MAP for 23 days. Inconclusion an atmosphere low in O2 (1.5%) and high in CO2 (17%) concentration retained qualitycharacteristics (color, exterior appearance and organoleptic attributes), reduced the proliferation of the‘pepper spot’ disorder and extended storage period up to 80% extending likewise the marketability of theend product as ‘ready to use’ salad.

Study on the stability of suspensions based on biomimetic apatites aimed at biomedical applications

Nanobiotechnologies have lately attracted much attention, both from therapeutic and diagnosis perspectives. In this view, the development of colloidal formulations of biocompatible nanoparticles capable of interacting with selected cells or tissues raises a particular interest, especially in link with cell-based pathologies such as cancer. In this context, the follow-up of colloidal stability and other physico-chemical features is of foremost relevance. In this contribution, we have focused our study on hybrid colloids based on biomimetic nanocrystalline apatites (analogous to those found in bone mineral) stabilized by adsorption of 2-aminoethylphosphate (AEP) molecules; these nanoparticles being intended to interact with cancer cells either for medical imaging (by conferring luminescence features to the apatite phase) or for therapeutic purposes. We show that various physico-chemical characteristics of the suspensions vary with time, including viscosity and mean particle size, suggesting a progressive structuration of the suspensions. Similar modifications were also noticed during the purification by dialysis. Finally, we report on preliminary experiments aimed at drying the colloids while retaining their capacity to recover their initial state after re-immersion in aqueous medium; so as to enable extended storage periods for the nanoparticles in their dry state while allowing their re-suspension at the time of use. On this matter, the addition of glucose prior to freeze-drying was found to be an effective way to avoid the formation of aggregates during drying.This contribution thus confers additional information relative to the stability of AEP-stabilized biomimetic apatite colloidal formulations, which proved in previous studies to be of particular relevance for nanomedicine.

Delayed replantation of an avulsed maxillary premolar with open apex: A 24 months follow-up case report

Avulsion of permanent teeth is most serious of all dental injuries and accounts for 1-16% of all traumatic injuries, of which maxillary incisors are most commonly involved. However, in this report a rare case of isolated avulsed immature premolar has been described. The patient had reported more than 3 hours after the trauma with a tooth stored in dry condition and soil contamination. The prognosis depends on measures taken at the place of accident or the time immediately after avulsion. Replantation is the treatment of choice, but cannot always be performed immediately. An appropriate emergency management and treatment plan is important for good prognosis. In this report stepwise management of an avulsed immature maxillary premolar with extended period of dry storage has been described followed up for a period of 2 yrs.