Dry Storage Conditions Research Articles

Desiccation and storage behavior of bay laurel (Laurus nobilis L.) seeds

The effect of seed moisture content (m.c.) and seed storage conditions of bay laurel (Laurus nobilis L.) was investigated in relation to seed viability. In the first experiment, the effect of drying rate on seed moisture and seed germination was investigated. Fresh seeds, with their original moisture content displayed a germination percentage of 55.1%. When the seed moisture content was reduced by 2.0% in an oven, the germination percentage rose to 81.0%. When the seed moisture content was reduced even more by using the same method, the germination percentages decreased dramatically. Reducing the seed moisture content to 28.7 and 23.5% by drying the seeds in alternating room conditions resulted in an increase of seed germinability to 84.3 and 90.9%, respectively. The drying of the seeds for 45, 60 and 75 days reduced their seed germination to 66.8, 49.4 and 48.0%, respectively. Reducing seed moisture content below 15.0% resulted in practically nullifying seed germinability. The fact that bay laurel seeds cannot retain their germinability at lower moisture contents demonstrates that it is a species with recalcitrant seeds. In the second experiment, moist and dry storage conditions were tested under different temperatures and moisture contents. The storage experiment showed that the most effective way of conserving the bay laurel seeds is moist storage at 0 ± 1°C for 4 months without previous drying of the seeds.

Development of soil water repellency in the course of isothermal drying and upon pH changes in two urban soils

AbstractThe potential influence of pH on water repellency in soils has already been mentioned in some studies, but no clear correlation between these parameters has been found to date. In addition, although correlations of water content and water repellency have been found in numerous studies, the influence of drying and subsequent storage conditions on water repellency are still unclear. In this study, a series of samples showing water repellent and wettable conditions respectively at field moist states from two urban locations were compared regarding two main aspects: (i) the influence of artificial pH‐changes on their wetting behaviour and (ii) sample wettability changes during drying for different drying temperatures. The assumption made in a study by Hurraß and Schaumann (2006) on the same sample site, that differences in wettability of closely neighboured samples from one sample location can be interrelated with differences in pH, was confirmed. However, in contrast to the assumption that rising pH will improve the wettability and decreasing pH will intensify water repellency, we found a maximum in water repellency at a pH above the initial pH. The results from drying samples at different temperatures confirmed the dependence of water repellency development on the drying temperature. Additionally, we could confirm the conclusion from previous studies that the water content alone cannot explain the water content–WDPT (water drop penetration time) relationship. The results from drying and pH changes show that some location specific factors, like the number of pH active functional groups, may be relevant for sample wettability. As additional mechanism, which may be partly antagonistic to the influence of the water content, we assume temperature‐dependent conformational changes in SOM (Soil Organic Matter). It seems that aspects of these conformational changes may additionally be governed by pH in one of our two locations. Copyright © 2007 John Wiley & Sons, Ltd.

Sol-gel-based optical sensor for the detection of aqueous amines

We present an optical sensor for the detection of aqueous amines obtained by incorporating chromoionophore XV (ETH(T) 4001) into sol-gel thin films. Acid- and base-catalyzed sol-gel processes were studied to prepare stable ormosil layers using various amounts of organically modified sol-gel precursor such as methyltriethoxysilane (MTriEOS). The sensor layers were coated with a protective layer of microporous white polytetrafluoroethylene (PTFE) in order to prevent interference from ions and ambient light. The measurements were carried out in a flow-through cell in the reflection mode. Acid-catalyzed ormosil layers (pH 1) based on the copolymerization of tetraethoxysilane (TEOS) and MTriEOS did not show any change in signal upon exposure to aqueous amine solutions, while base-catalyzed sensor layers (pH 3 and 13) showed significant changes in signal. The response time (t (100)) for the base-catalyzed sensor layer L3 (pH 13) upon exposure to different solutions containing 0-608 mmol L(-1) aqueous propylamine was 20-30 s, the regeneration time was 70 s and the detection limit was 0.1 mmol L(-1). The sensor response was reproducible and reversible. The porous ormosil layers permit dry sensor storage conditions.

Factors affecting arsenic speciation in environmental samples: sample drying and storage

Arsenic is a ubiquitous element. Its toxicity, mobility, and bioaccumulation depend usually on its chemical form, and therefore, arsenic speciation is indispensable for the assessment of environmental risk and human hazard. Little is known about the effect of sample preparation procedures, such as drying and storage, on the resulting arsenic speciation. In this study, we investigated the influence of different drying methods and storage conditions on the arsenic speciation in mineral soils, organic soils, and plants. Drying soils and plants using different methods may change the concentrations of the total methanol–water (20%, v/v) extractable arsenic, the proportion of organic arsenic and the ratio of arsenite-to-arsenate. Loss of methanol–water extractable arsenic compounds (up to 63%) was observed particularly in the samples rich in water. Following drying, the speciation of organic arsenic changed less than that of inorganic arsenic. Drying showed little influence on the total arsenic determination. None of the storage methods tested could preserve the arsenic speciation in organic soils and plants, although arsenic speciation after one-month storage varied less in freeze-dried samples than wet samples. Storage of the samples at low temperatures (2 or −20°C) had the largest impact on the samples rich in organic matters, leading to less arsenic being extractable by methanol–water. Both drying and storage of the soil and plant samples changed apparently the arsenic speciation. Therefore, we recommend conducting the arsenic speciation possibly with fresh and wet samples, so that the results of arsenic speciation may be more approaching the original states.

Ochratoxin A and citrinin loads in stored wheat grains: Impact of grain dust and possible prediction using ergosterol measurement

Crop storage should be carried out under hygienic conditions to ensure safe products, but sometimes grain dust which has settled from previous storage may be left over and incorporated to the following stored grains. This paper describes the results obtained using a lab model developed in order to assess the impact of grain dust incorporation for its direct contribution as a contaminant but also as an inoculum in stored wheat. Settled grain dust (4 samples) released from Belgian grain storages were collected and analysed by HPLC for ergosterol, ochratoxin A (OTA) and citrinin (CIT) content. For OTA and for ergosterol, there was a high degree of variability in concentrations found in the dust samples (from 17.3–318 ng g−1 and from 39–823 µg g−1, respectively) whilst for CIT, the range was less significant (from 137–344 ng g−1). Incorporation of grain dust into wheat storage contributed to an increase in the concentrations of mycotoxins in the stored grain. Dust acts as a contaminant and as an inoculum. According to these two ways, patterns of mycotoxin generation vary with the nature of the mycotoxin, the mycotoxigenic potential of dust and the water activity of the wheat. OTA and CIT showed a very versatile image when considering the amounts of toxins produced under the selected experimental conditions. The development of a robust tool to forecast the mycotoxigenicity of dust was based on the determination of ergosterol content as a general marker of fungal biomass. Present results suggest that this predictive tool would only be valid for predicting the contamination level of CIT and OTA at reasonable moisture content (14–20%). The potential risk of having highly contaminated batches from stock to stock may thus occur and this paper discusses possible pathways leading to OTA and CIT contamination either under wet or dry storage conditions. We therefore, recommend taking precautionary measures not only by controlling and maintaining moisture at a reasonable level during storage of the raw materials but also by paying more attention to the cleaning of the stores before loading in the new harvests.

Properties and biological control activities of aerial and submerged spores in Trichoderma asperellum SKT-1

Trichoderma asperellum SKT-1, a biocontrol agent that is highly effective against rice seedborne diseases, forms submerged spores by liquid culture. These submerged spores had some common properties with aerial spores, but differed in surface topology and internal organization. Aerial spores, so called conidia, maintained high viability under dry storage conditions, whereas the viability of submerged spores was reduced. The cell wall of submerged spores was thinner than that of aerial spores, and the surface was smooth in contrast to the irregular pyramidal warts of aerial spores. Both submerged and aerial spores were highly effective against “Bakanae” disease by seed-treatment. Therefore, these two-types of spores were suitable for different applications.

Polyethyleneimine-grafted poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) membranes for reversible glucose oxidase immobilization

Glucose oxidase (GOD) was immobilized onto polyethyleneimide (PEI) grafted poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) (poly(HEMA-co-GMA)) membranes. The maximum GOD immobilization capacities of the poly(HEMA-co-GMA-4)-PEI membrane were 84 μg/cm 2. The activities of GOD-immobilized onto poly(HEMA-co-GMA-1-5)-PEI membranes were in the range 7.6–14.5 U/cm 2. The storage conditions for the immobilized enzyme preparations were studied and the immobilized enzymes had a long-storage stability (only 7 and 24% activity decrease in 3 months under wet and dry storage conditions, respectively).

The Effects of Depth and Duration of Burial on Seasonal Germination, Dormancy and Viability of Galium aparine and Bifora radians Seeds

AbstractThe effects of depth and duration of burial on seasonal germination, primary/secondary dormancy, and viability of Galium aparine and Bifora radians were studied in two experiments. The seeds of both species were buried at different depths with four replications in a split‐plot design in the first experiment. The seeds were exhumed from the field at monthly intervals and germinated under suitable temperature conditions. In the second experiment, the seeds of both species were stored at 20 °C and 50 % relative humidity after harvest. Four replicates of seeds from each species were adjusted for germination tests at monthly intervals. Non‐germinated seeds of either the first or the second experiment were treated with triphenyltetrazolium chloride in order to enhance the viability of seeds at monthly intervals until the end of the experiment. The seeds of G. aparine showed cyclic behaviour in the burial experiment. The germination percentage of B. radians seeds never exceeded 8 % at all depths until 7 months after burial due to primary dormancy. Thereafter, the seeds showed typical cyclic behaviour with modest deviation. In both the species, the depth of burial strongly affected seed viability. In the dry storage conditions, the seeds of G. aparine and B. radians showed a high level of primary dormancy. The percentage viability of seeds declined depending on the duration of storage.

Trehalose conserves expression of bullous pemphigoid antigen 180 during desiccation and freezing

Bullous pemphigoid antigen 180 (BP180) is targeted by autoantibodies in a variety of subepidermal blistering skin diseases. We have recently developed a simple, highly specific and sensitive immunofluorescence (IF) assay for the detection of circulating antibodies against BP180. This novel assay involves the expression of full-length (FL) BP180 in Sf21 insect cells that are then examined under IF microscopy after staining with anti-BP180 antibodies. Application of this assay as a routine diagnostic tool requires long-term storage of FL-BP180, which can result in substantial loss of expression. Here, we show that the disaccharide trehalose, a natural cryo- and lyoprotectant, is capable of preserving the FL-BP180 antigen expressed in Sf21 insect cells under various (dry) storage conditions including 40°C, room temperature (RT), 4–8, −20, and −80 °C. The protective effect was dose-dependent reaching a maximum at about 200 mM trehalose. Trehalose was superior to other sugars or conventional cryoprotective agents (e.g. sucrose, myo-inositol, DMSO) in preventing greatly reduced antigen expression. Trehalose conserved the expression of both extra- and intracellular epitopes of FL-BP180. Interestingly, protection of the intracellular domain was only observed when trehalose was introduced into the cytosol. Trehalose significantly prolonged the storage time of FL-BP180 expressed in Sf21 insect cells, thus permitting the routine use of the IF assay in clinics for the detection of serum antibodies. The method described here has potential applications for the preservation of other transmembrane proteins.

Effect of intensity of maceration on digestibility and intake of alfalfa hay and silage fed to sheep

A study was conducted to determine the influence of intensity of mechanical conditioning on the nutritive value of alfalfa conserved as hay or silage. Fresh alfalfa was mowed and conditioned at three levels of maceration prior to field wilting during 45 h for silage (29–39% DM) or 94 h for hay (87% DM, after barn-curing), under light rain conditions during the first 2 d. The conditioning treatments were: control (conventional mowing-conditioning), light maceration (one passage through three knurled steel rolls), medium maceration (two passages), and intense maceration (three passages). Concentrations of NDF, ADF, hemicellulose, CP-NDF, and CP-ADF increased linearly (P < 0.001) with the level of maceration. Silage pH, acetic acid, propionic acid, and butyric acid increased, while lactic acid decreased (P < 0.001), with the level of maceration. The effective rumen degradabilities of DM, CP, and NDF, measured with fistulated cows, were not affected (P > 0.10) by the level of mechanical conditioning. Forty-eight male sheep (46.8 ± 6.7 kg BW) were fed a 100% forage diet according to a completely randomized design with a 2 × 4 factorial arrangement of treatments (two storage methods and four levels of conditioning). Under restricted feeding, DM, NDF, ADF, and hemicellulose digestibilities decreased linearly (P < 0.001) with the level of maceration. However, the digestibility of CP-NDF increased with the level of maceration; the effect was more important in hay than in silage (P < 0.001 for the interaction). When silages were fed ad libitum to 24 sheep, daily DMI was 2.31, 2.88, 2.76, and 2.41% of BW and DM digestibility was 60.8, 60.1, 56.2, and 46.7%, for control, light, medium, and intense maceration, respectively (P < 0.01). The results suggest that light maceration increases DM intake while maintaining digestibility of forages fed to sheep. Because of humid conditions and potential soil contamination due to multiple windrow pickup, intense maceration caused severe nutrient loss, which might be avoided under dry field wilting and good storage conditions. Key words: Alfalfa, hay, silage, digestion, degradability, intake

Using Seed Volatiles as a Possible Indicator for Seed Deterioration during Storage

All kinds of plant seeds evolve volatile compounds during storage. However, a reliable deterioration forecast method is still not established using volatile evolution, even though some preliminary work indicated a relationship between volatile evolution and seed deterioration (Fielding and Goldsworthy, 1982; Hailstones and Smith, 1989; Zhang et al., 1993). Here we review some of the previous work concerning seed volatiles and present some more recent research on the effects of seed moisture content on deterioration. We found that volatile evolution from seeds was controlled by seed moisture level. Generally, seeds tended to evolve more hexanal and pentanal under extremely dry conditions (below 25% equilibrium RH). The production of hexanal and pentanal decreased with increasing seed moisture level. On the other hand, methanol and ethanol increased with increasing seed moisture. All of the volatile compounds accumulated in the headspace of the seed storage container during storage. Therefore, it should be possible to use different volatiles to indicate the deterioration of seeds stored under different moisture levels. We suggest that hexanal may be used for seed assessing deterioration under dry storage conditions (below 25% equilibrium RH), while ethanol may be used for seeds stored under higher moisture conditions (above 25% equilibrium RH). [

Reagentless amperometric glucose dehydrogenase biosensor based on electrocatalytic oxidation of NADH by osmium phenanthrolinedione mediator

The mediator Os(4,4′-dimethyl, 2,2′-bipyridine)2(1,10-phenanthroline-5,6-dione) was used for the catalytic oxidation and recycling of NADH. The mediator, with a redox potential of almost 0 V versus Ag/AgCl, shows clear electrocatalysis of NADH at 0.1 V versus Ag/AgCl at pH 6.0. Carbon paste electrodes modified with the mediator show a clear electrocatalytic wave reaching limiting current densities at 0.15 V versus Ag/AgCl of the order of 140 µA cm–2 l mmol–1 NADH. Reagentless dehydrogenase carbon paste amperometric electrodes for glucose were developed, mixing the mediator, glucose dehydrogenase and NAD+ in the paste. These electrodes were optimized with respect to amounts of enzyme, mediator and NAD+ and were studied with a variety of electrochemical techniques. The results suggest that the response is limited by the enzymic step of the reduction of NAD+ or the oxidation of the substrate. The glucose electrodes show maximum current densities of >0.5 mA cm–2 and very good operational stability in continuous operation; under dry storage conditions their lifetime exceeded 1 month.

Oxidation of Fuel Rod under Dry Storage Condition

Oxidation tests of irradiated and un-irradiated rod with an artificial defect hole were Per-formed in air and air-argon mixed gas between 473K and 513K to study the oxidation behavior of damaged fuel rod during dry storage. Rods oxidized in air showed diameter in-crease due to volume expansion caused by the generation of U3O8 and the cladding of irradiated rod was broken after the diameter increase had reached about 2%. X-ray diffraction and metallography showed that the oxidation of irradiated UO2 pellet occurred preferentially at the grain boundary and that the crystal structure corresponding to U4O9 remained stable even after about 11,200h oxidation in air at 473K. It was suggested that the difference of the oxidation between irradiated and un-irradiated rods was due to FP gas bubble accumulation at grain boundary and FP accumulation in UO2 matrix. The oxidation rate of fuel rod in air-argon mixed gas was lower than that in air irrespective of irradiation. The irradiated rod in low oxygen partial pressure showed very little deformation.

Oxidation of Fuel Rod under Dry Storage Condition.

Oxidation tests of irradiated and un-irradiated rod with an artificial defect hole were Per-formed in air and air-argon mixed gas between 473K and 513K to study the oxidation behavior of damaged fuel rod during dry storage. Rods oxidized in air showed diameter in-crease due to volume expansion caused by the generation of U3O8 and the cladding of irradiated rod was broken after the diameter increase had reached about 2%. X-ray diffraction and metallography showed that the oxidation of irradiated UO2 pellet occurred preferentially at the grain boundary and that the crystal structure corresponding to U4O9 remained stable even after about 11,200h oxidation in air at 473K. It was suggested that the difference of the oxidation between irradiated and un-irradiated rods was due to FP gas bubble accumulation at grain boundary and FP accumulation in UO2 matrix. The oxidation rate of fuel rod in air-argon mixed gas was lower than that in air irrespective of irradiation. The irradiated rod in low oxygen partial pressure showed very little deformation.

In vitro flexural fatigue limits of dental composites.

The flexural fatigue test equipment developed was used to study the fatigue behavior of dental restorative composites, using a "staircase" approach. Three commercial composites were tested after dry and wet storage conditions. The findings indicate that the method is accurate and reliable, and that changes due to water sorption are clearly reflected: The flexural fatigue limit decreases after water sorption. From the present results it seems that under environmentally controlled conditions, the fatigue behavior is characterized by a well-defined fatigue stress level above which the composites tested fail rapidly, and below which they survive.

Oxidation of UO2under Dry Storage Condition

Oxidation of UO²under Dry Storage Condition

Oxidation of UO2 under Dry Storage Condition.

Click to increase image sizeClick to decrease image sizeKEYWORDS: uranium dioxideoxidationhigh temperaturedry storagedensityoxygenpartial pressurespentFuelsuranium oxidesair invasions

Enhancement of the thermal and storage stability of urease by covalent attachment to phospholipid-bound silica.

Urease was immobilized directly on silanized silica surfaces carrying alkyl moieties with terminal carboxylic groups. The enzyme was also covalently attached to phospholipid-bound silanized silica surfaces through the terminal carboxyl moiety on the sn-2 acyl chain of the lipid. The surfaces were characterized by X-ray photoelectron spectroscopy and ellipsometry. The activity of the immobilized urease was determined by UV spectrophotometry using a urea/bromocresol purple substrate. The enzymic activity decreases exponentially upon storage under dry solid conditions for 1 week or upon heating to 100 degrees C in the case of the silane/enzyme surfaces. On the other hand, the enzyme immobilized on phospholipid-carrying silica surfaces retained its entire original activity under dry storage or heat treatment conditions. Such immobilized urease systems could find extensive applicability in the design of in vivo dialysis equipment or for on-line monitoring of urea.

The applicability of the strain-hardening rule to creep deformation of Zircaloy fuel cladding tube under dry storage condition

Variable stress and temperature creep tests were carried out at temperatures between 626 and 693 K for the Zircaloy-4 tubular specimens in the hoop stress regime 55 to 125 MPa to examine the applicability of the strain hardening rule to creep deformation of Zircaloy-4 fuel cladding tube. Results were compared with those of the constant temperature/stress tests, indicating that the strain hardening rule but not the time hardening rule can be applicable for predicting creep deformation of fuel cladding tube at temperatures tested. It is also suggested that although Zircaloy-4 fuel cladding tube tends to deform under multiaxial condition, it can satisfy the requirements for the strain hardening rule at temperatures of interest during dry storage condition.

Creep deformation and rupture properties of unirradiated Zircaloy-4 nuclear fuel cladding tube at temperatures of 727 to 857 K

Creep deformation and rupture properties of an unirradiated Zircaloy-4 tube were examined at temperatures of 727 to 857 K to obtain data for evaluating spent fuel integrity under the off-normal dry storage condition. Creep tests were carried out on internally gas pressurized tubular specimens with end plugs welded to both ends.