Low Moisture Levels Research Articles

Short distances between extreme microhabitats do not result in ecotypes in Syntrichia caninervis

Phenotypic variation occurs in many populations of plants. When this variation occurs along an environmental gradient, the immediate question is whether the variation is attributed to phenotypic plasticity, ecotypes, or some combination of the two. The moss Syntrichia caninervis appears morphologically variable along an environmental gradient changing rapidly from low light, low temperature, and high moisture levels in the understory microhabitat to high light, high temperature, and low moisture levels in the intershrub microhabitat. We tested for the presence of physiological variation using recovery from a heat-shock event in a mimicked microhabitat light environment, and for morphological variation using a common garden with the ultimate goal of attributing observed variation to plasticity, genetic variation, or a combination. The results suggest that plasticity plays a large role in trait variation. Photosynthetic recovery depended on the current light levels of an environment and not the original microhabitat. The supposed morphological variation in the field was not reflected in the test traits (awn length, leaf area, and shoot volume) and further growth in a common garden continued to show no variation between microhabitats.

Research Spotlight: Dual‐dynamic approach improves soil water transport model

To simulate perfectly the flow of water through the ground, one would need to know the details of every pore, passage, and air pocket in the soil. To circumvent such daunting requirements, researchers simulate soil moisture transport as if the water were flowing through a series of cylindrical tubes, with the groundwater transport influenced by both gravity and pressure. This simplified representation holds up well when the soil is wet, but the analogy begins to break down when moisture levels drop. At very low moisture levels a dynamic nearly negligible at high flow rates begins to dominate: the adsorption of water onto soil particles. Water creates a thin film around individual grains of soil through molecular, ionicelectrostatic, and other attraction forces, but these interactions, while well known, are generally overlooked in models of soil moisture transport.

Rheological, moisture and ash content analyses of a gum resin from Commiphora Africana

A gum resin was isolated from Commiphora africana. In order to assess its application to industry, it was subjected to rheological, moisture and ash content studies. For rheological studies, a rotational viscometer which had the ability to characterize both Newtonian and non-Newtonian systems was used. The gum resins from C. africana exhibited low shear stress even at high concentration of the gum resins. The change in shear stress with temperatures produced almost a linear graph with a gradient of 0.06. In addition, the gum resin from this plant species was affected by the addition of salts and would have little application in formulations that contain salts. The moisture content obtained was 10.6±0.04%.The low level of moisture in this gum resin appeared to be desirable since it will attract little bacterial or fungal growth in the formulation. The ash content was 3.64±0.01%. The present study has demonstrated that this gum has potential as a product for the cosmetic, pharmaceutical and food industries provided further studies are carried out to identify the phytoconstituents in the gum as well as toxicity studies. Key words: Commiphora Africana, gum, rheology, moisture, shear stress, ash content, pharmaceuticals, food industry.

The aggregation of bovine serum albumin in solution and in the solid state.

The aggregation of bovine serum albumin (BSA) in the solid state and in solution was studied to elucidate the effect of water mobility on the aggregation rate and mechanism. The results suggest that the freeze-dried BSA forms covalently-bonded aggregates via disulphide bonding during storage in the moistened solid state and in solution. The aggregation rate largely depended on the water content. The freeze-dried BSA to which a small amount of water was added (in the moistened state) was found to be more liable to aggregation than that in solution. The aggregation rate in in the moistened solid state exhibited a maximum at a very low level of moisture. In contrast, the aggregation rate in solution increased with increasing ratio of water to protein (with decreasing protein concentration). The results suggest that the increased rate is related to the increase in water mobility, as measured by the spin-lattice relaxation time, T1, of water using 17O NMR, with increasing ratio of water to protein.

The effect of storage conditions on coffee seed and seedling quality

Summary Obtaining commercially useful coffee seedlings is hindered by slow, uneven germination and low tolerance to desiccation as well as reduced coffee seed longevity. Coffee seeds have been considered recalcitrant, orthodox and even intermediate with varying results. Current recommendations suggest that coffee seeds can be safely stored between 10-11% f.w.b. at 15°C. However, after drying and storage, coffee seeds lose vigour, and seeds stored after drying cannot be used for producing seedlings. Coffee seedling producers usually sow seeds immediately or lightly dry them after harvest for a short storage period, if necessary. It is highly desirable that seeds are stored safely to optimize coffee seedling production at the appropriate time and season with ideal climatic conditions for planting in the field. The objective of this study was to determine the quality of coffee seedlings produced from seeds stored with high, medium and low moisture levels under hermetic conditions at 10 and 20°C. Seed and seedling quality were assessed before and after nine months storage. Only the germination of seeds harvested at the cherry stage, evaluated before and after the storage at 10°C, was not affected by moisture content, but these seeds lost vigour and did not produce suitable seedlings for planting when stored for nine months. Seedlings produced in the nursery from seeds with 47 and 12% moisture content performed the same as those from greenish-yellow seeds, but they produced a leaf area that was five times smaller, a stem height three times shorter, and had 1.7 times fewer pairs of true leaves than coffee seedlings produced from fresh seeds. Storage at 20°C was not suitable for coffee seeds, especially those at 18% moisture content whose quality declined drastically. These results suggest that coffee seeds do not tolerate desiccation and that their storage behaviour classification should be reviewed.

Moisture content in timber decking exposed to bushfire weather conditions

SUMMARYIgnition of the external combustible elements of a building is one of the key factors leading to house loss in bushfires. Timber elements contain moisture that migrates into and out from the timber surface, depending on the surrounding ambient conditions. In extreme hot and dry conditions, such as those associated with severe bushfire weather, the moisture contents (MCs) in building timbers can drop well below the normal levels. In this paper, we not only qualify a methodology to assess the likely MCs of timbers under typical bushfire conditions, but also quantify the low levels of moisture that can be expected for the climatic conditions experienced in Melbourne—one of Australia's bushfire‐prone regions. Copyright © 2011 John Wiley & Sons, Ltd.

Pathogen destruction and solids decomposition in composting latrines: study of fundamental mechanisms and user operation in rural Panama

The relationship between temperature, high pH, desiccation, decomposition, pathogen destruction, and user operation in active double vault urine diverting (DVUD) composting latrines located in the Bocas del Toro region of Panama was assessed. Latrine samples were analyzed for temperature, pH, % moisture, carbon-to-nitrogen (C/N) ratio, and presence of specific pathogens. Surveys and visual inspections were used to verify use and type of dry material desiccant added. Measurements supported findings that compost latrines do not reach temperatures sufficient to destroy all pathogens. pH measurements showed that many latrines were operating within the range for ideal aerobic decomposition, a pH of 7.5-8.5, but only 17% of latrines measured pH 9 or above. Almost 100% of composting latrine users added sawdust and wood ash, to lower moisture level and provide carbon for decomposition. However, the recommended amount of desiccant added was insufficient to reduce moisture to the suggested 25% for pathogen destruction and C/N ratios remained in the range of raw human faeces. Importantly, pathogens, mainly helminths, were still present in compost stored for the 6-month contact time. The latrines have conflicting goals of pathogen destruction and aerobic decomposition. Recommendations are made regarding operation of composting latrines and disposal of composted material.

Orbital, ice sheet, and possible solar controls on Holocene moisture trends in the North Atlantic drainage basin

Holocene patterns of hydroclimatic change in the North Atlantic region are poorly understood despite the importance to climate of the region9s freshwater flux to the ocean. Here we reconstruct the history of moisture balance in the North Atlantic drainage by compiling lake-level records from 95 lakes in Europe and North America. We show that recent millennia were significantly wetter than much of the Holocene in both regions. Only 15% of lakes studied in the North Atlantic basin were low in the past millennium. In contrast, 50% of lakes were low at 10 cal kyr B.P. Low moisture levels in the early Holocene likely resulted from high summer and fall insolation and the influence of the continental ice sheets; water levels rose in many areas as these influences diminished. A principal components analysis of the lake-level data, however, also indicates that Holocene atmospheric circulation changes, possibly driven by solar activity, generated additional moisture variation, including low water levels at 5–2 cal kyr B.P. in eastern North America and Scandinavia.

Development of a lyophilized plasmid/LPEI polyplex formulation with long-term stability—A step closer from promising technology to application

Cationic polymer/DNA complexes are limited by their instability in aqueous suspensions and usually have to be freshly prepared prior to administration. Thus, the development of isotonic lyophilized polyplex formulations with long-term stability is a desirable goal. Polyplexes based on 22 kDa linear polyethylenimine were prepared using a micro-mixer method. Freeze-thawing and lyophilization were performed on a pilot scale freeze-drier. Several excipients (trehalose, sucrose, lactosucrose, dextran, hydroxypropylbetadex or povidone and combinations thereof) at varying concentrations were evaluated for their stabilizing potential against freezing and dehydration induced stresses. For stability testing the lyophilized samples were stored for 6 weeks at 2–8 °C, 20 °C and 40 °C, respectively. Polyplex samples were characterized for particle size, zeta potential, their in vitro transfection efficiency and metabolic activity in Neuro2A cells. In addition, liquid samples were investigated for turbidity and number of sub-visible particles and solid samples were analyzed for residual moisture content, glass transition temperature and sample morphology. L-histidine buffer pH 6.0 was selected as effective buffer. In isotonic formulations with 14% lactosucrose, 10% hydroxypropylbetadex/6.5% sucrose or 10% povidone/6.3% sucrose, particle size was < 170 nm for all formulations and did not change after storage for 6 weeks at 40 °C. Polyplexes formulated with lactosucrose or hydroxypropylbetadex/sucrose showed high transfection efficiencies and cellular metabolic activities. Absence of large aggregates was indicated by turbidity and subvisible particle number measurements. The current standard limits for particulate contamination for small volume parenterals were met for all formulations. All samples were amorphous with low residual moisture levels (< 1.3%) and high glass transition temperatures (> 90 °C).

The Impact of Heat-Moisture Treatment on Molecular Structures and Properties of Starches Isolated from Different Botanical Sources

Heat-moisture treatment is a hydrothermal treatment that changes the physicochemical properties of starches by facilitating starch chain interactions within the amorphous and crystalline domains and/or by disrupting starch crystallites. The extent of these changes is influenced by starch composition, moisture content and temperature during treatment, and by the organization of amylose and amylopectin chains within native starch granules. During heat-moisture treatment starch granules at low moisture levels [(<35% water (w/w)] are heated at a temperature above the glass transition temperature (T g ) but below the gelatinization temperature for a fixed period of time. Significant progress in heat-moisture treatment has been made during the last 15 years, as reflected by numerous publications on this subject. Therefore, this review summarizes the current knowledge on the impact of heat-moisture treatment on the composition, granule morphology, crystallinity, X-ray pattern, granular swelling, amylose leaching, pasting properties, gelatinization and retrogradation parameters, and susceptibility towards α-amylase and acid hydrolysis. The application of heat-moisture treatment in the food industry is also reviewed. Recommendations for future research are outlined.

Effects of inoculation with lactic acid bacteria on the bacterial communities of Italian ryegrass, whole crop maize, guinea grass and rhodes grass silages

Italian ryegrass (IR), whole crop maize (WM), guinea grass (GG) and rhodes grass (RG) were stored in laboratory silos for 30 d with and without Lactobacillus plantarum or Lactobacillus brevis inoculation. The grasses were wilted to low moisture levels (about 500 g/kg) prior to ensiling, while WM was ensiled directly after harvest. Microbial counts and bacterial community analyses were undertaken by plate-culture and denaturing gradient gel electrophoresis (DGGE), respectively, on pre- and post-ensiled crops. A total of 31 DGGE bands were retrieved, cloned, and sequenced to identify bacterial species according to their 16S rRNA gene sequences. Inoculation with L. plantarum and L. brevis increased (P<0.05) lactic acid and decreased (P<0.05) 2,3-butanediol contents in wilted grass silages, with higher (P<0.05) contents of lactic acid observed in L. plantarum-inoculated silages compared to L. brevis-inoculated silages. Inoculation with L. brevis increased (P<0.05) both lactic and acetic acid contents in IR silage and intensified lactic acid production in GG and RG silages. Inoculation with either L. plantarum or L. brevis did not affect fermentation of WM silage, except that the lactic acid to acetic acid ratio increased (P<0.05) in L. plantarum-inoculated silage. Differences in inoculation effects could be accounted for by changes in bacterial communities present in the silages. Interestingly, in wilted grass silages, the inoculation nearly eliminated the indigenous communities, leaving the inoculated species as the principal bacteria. In maize silage, desirable bacterial communities were found in untreated control, and the inoculated lactic acid bacteria (LAB) were additive to the uninoculated communities. Combination of fermentation product analysis and bacterial community analysis may describe the effects of LAB inoculation on the ensiling process.

A 40,000-yr record of environmental change from Burial Lake in Northwest Alaska

Burial Lake in northwest Alaska records changes in water level and regional vegetation since ∼ 39,000 cal yr BP based on terrestrial macrofossil AMS radiocarbon dates. A sedimentary unconformity is dated between 34,800 and 23,200 cal yr BP. During all or some of this period there was a hiatus in deposition indicating a major drop in lake level and deflation of lacustrine sediments. MIS 3 vegetation was herb-shrub tundra; more xeric graminoid-herb tundra developed after 23,200 cal yr BP. The tundra gradually became more mesic after 17,000 cal yr BP. Expansions of Salix then Betula, at 15,000 and 14,000 cal yr BP, respectively, are coincident with a major rise in lake level marked by increasing fine-grained sediment and higher organic matter content. Several sites in the region display disrupted sedimentation and probable hiatuses during the last glacial maximum (LGM); together regional data indicate an arid interval prior to and during the LGM and continued low moisture levels until ∼ 15,000 cal yr BP. AMS 14C dates from Burial Lake are approximately synchronous with AMS 14C dates reported for the Betula expansion at nearby sites and sites across northern Alaska, but 1000–2000 yr younger than bulk-sediment dates.

Effect of Pine Wood Shavings, Rice Hulls and River Bed Sand on Broiler Productivity When Used as a Litter Sources

As the poultry industry has grown and expanded and as alternative uses of wood by-products have expanded, the availability of wood shavings and sawdust for litter materials has been challenged. Litter type utilized is largely dependent upon local availability of the material and location of the farm. Unfortunately, the availability of pine shavings has steadily decreased due to competition for its use from other industries and use as an energy source. The objective of this research was to evaluate conventional litter sources to sand as a substitute litter. For the experiment Pine Wood Shavings (PWS), Rice Hulls (RH), River Bed Sand (S) and river bed sand top dressed with pine wood shavings (SP) were the four litter source treatments implemented. Chicks were identified and randomly allocated in a randomized complete block design. Litter temperatures were recorded prior to bird placement. Body weight, cumulative feed consumption, feed conversion (feed: body weight) and litter moisture were determined on a weekly basis through 42 days of age. Mortality was recorded daily. At processing carcass weight, percentage carcass yield without giblets and gizzard yield were determined on a prechilled basis. Litter surface temperatures were significantly (p<0.001) higher for PWS, RH and SP compared to just S alone. Broilers raised on S had significantly (p<0.001) higher body weights and consumed more feed than those raised on PWS or RH throughout the 42 days. No significant differences were found for feed conversion, mortality or carcass yield. Carcass weight and gizzard yield were significantly (p<0.001) higher for birds raised on S. Sand maintained approximately 15% lower moisture level in comparison to PWS and RH and a 5% difference to SP (p<0.001). In conclusion, sand can potentially be used as an alternative litter material for growing broilers.

An In-Line, Non-Invasive Cotton Moisture Measurement Device for Gin Ducts

The management of moisture in cotton during ginning remains one of the most important factors in determining final quality. Resistance plates are typically used to measure moisture in seed-cotton and lint as it is processed through the gin, but these are limited by inaccuracies that arise from the small proportion of cotton tested, contamination of the sensor, and by the non-linear response to low and high moisture levels. In this article, we present a new sensing device that has potential for measuring the moisture of lint while it is being processed in the gin. The device combines large-area capacitance plates with light detectors to measure the mass and moisture of material traveling quickly under pneumatic pressure or gravity through gin ducts. Industrial trials showed significant correlations between moisture values given by the device and values measured off-line. This was despite only a narrow range of moisture contents (4.9% to 6.1%) occurring during the trial period. Further trials are necessary to evaluate the device over a wider range of conditions and to examine its potential to control ginning processes.

The influence of Bifidobacterium Bb-12 and lactic acid incorporation on the properties of Minas Frescal cheese

The effects of a probiotic bacterium ( Bifidobacterium Bb-12) and lactic acid on the microbiological, physicochemical, rheological and microstructural proprieties of Minas Frescal cheese were evaluated after 1 day and after 28 days of storage (5 ± 1 °C). The cheese was produced with four different treatments: with no lactic acid (C1 and C2), with lactic acid (C3 and C4) and with bifidobacteria (C2 and C3). The cheese formulations containing bifidobacteria were classified as probiotic. The addition of bifidobacteria to the cheese did not influence its yield, protein or lipid levels one day after production. Moreover, after 28 days of storage, the cheese samples with no lactic acid showed lower moisture levels compared to the samples containing lactic acid ( P < 0.05). The absence of lactic acid had an influence on the rheological and microstructural behavior, making them more elastic, firm and compact, however all the cheese samples evaluated showed a higher tendency to viscosity than to elasticity. The Minas Frescal cheese with Bifidobacterium Bb-12 and lactic acid showed great potential as a functional food, with possible industrial and commercial application.

Sugar-Snap Cookie Dough Setting: The Impact of Sucrose on Gluten Functionality

In sugar-snap cookie making, sucrose influences the physicochemical transformations of the flour components and is responsible for both cookie sweetness and texture. Sucrose, together with low moisture levels, raises the starch gelatinization temperature to such an extent that little if any of it gelatinizes during baking. However, there is no agreement on the effects that it has on gluten during cookie making. The present study revealed that increasing sucrose levels in the recipe increasingly delay or inhibit gluten cross-linking, as judged from the loss of sodium dodecyl sulfate-extractable protein. This causes cookies containing higher sucrose levels to set later and to have a larger diameter. Gluten entanglement and/or cross-linking result in resistance to collapse, at the same time, cause setting during baking and, hence, determine cookie diameter.

Covariance between disturbance and soil resources dictates the invasibility of northern fescue prairies

Increasing environmental impacts of exotic organisms have refocused attention on the ability of diverse communities to resist biological invaders. Although resource availability, often related to natural and anthropogenic disturbances, appears central to the invasibility of biological communities, understanding the links between resources, diversity and invasibility is often confounded by the covariance among key variables. To test the hypothesis that community invasibility remains contingent on the type and intensity of disturbance and their impacts on plant community diversity and resource availability, we designed an experiment testing the invasibility of northern fescue prairies by smooth brome (Bromus inermis Leyss.), a Eurasian perennial grass, threatening the structure and function of prairie remnants throughout the Great Plains. Using soil disturbances and herbicide, we imposed treatments manipulating the diversity and resource availability of native prairies. Our observations demonstrate that the vulnerability of native prairies to exotic plant invasions remains contingent on resources. While the establishment of smooth brome seedlings increased with increasing disturbance, its impact depended on the availability of soil nitrogen. As a result, soil burial treatments, simulating disturbance by northern pocket gophers, provided poor recruitment areas for smooth brome, and their low levels of soil moisture and nitrogen, combined with the rapid recovery of the prairie community, compromised seedling establishment. Emphasizing the covariance of diversity and key environmental variables following disturbance, our findings illustrate the importance of disturbance type and intensity on community invasibility. Such a consideration is critical in the conservation and restoration of native prairie remnants throughout the Great Plains.

Response of Ag thick film microstrip equilateral triangular patch antenna to overlay of moisture laden soybean

PurposeThe purpose of this paper is to report on the Ku band microwave characteristics of moisture laden soya seeds using overlay technique.Design/methodology/approachKu band (13‐18 GHz) moisture dependent microwave permittivity, conductivity, penetration depth of moisture laden soybean (Glycine Max) using overlay on Ag thick film equilateral triangular patch antenna are studied. The change in the frequency response of the patch antenna due to change in moisture content of the soybean overlay has been used to obtain the various microwave properties.FindingsThe permittivities obtained are in the range expected of moisture laden soybean. As moisture content increases microwave dielectric constant, dielectric loss, and conductivity of soybean increases. Only the amplitude data have been used here.Originality/valueKu band characterization of soybean has been done using overlay technique. The thick film patch antenna is sensitive even to ∼4 percent moisture content in the overlay material. This can be used for even moisture sensing at low moisture levels. This paper is believed to be an original research report.

Identification and Mapping of New Sources of Resistance to Aflatoxin Accumulation in Maize

Maize (Zea mays L.) susceptibility to ear rot and aflatoxin accumulation by Aspergillus flavus (Link:Fr) has caused significant economic losses for farmers in the U.S. over the past 30 years. Aflatoxin outbreaks are generally associated with high temperatures and low moisture levels common to the southern U.S. To identify aflatoxin accumulation resistance quantitative trait loci (QTL) and linked markers for marker‐assisted breeding (MAB), a genetic mapping population of F2:3 family genotypes, increased by sib‐mating, was developed from Mp717, a maize inbred resistant to aflatoxin accumulation, and NC300, a southern‐adapted inbred with low levels of resistance and desirable agronomic traits. Replicated trials of the mapping population were subjected to A. flavus inoculation in Tifton, GA and Starkville, MS in 2004 and 2005. Quantitative trait loci on all chromosomes, except chromosomes 4, 6, and 9, were identified, and individual QTL explained from less than 1% to a maximum of 11% of the phenotypic variance in aflatoxin accumulation in grain. Both Mp717 and NC300 were found to contribute resistance to aflatoxin accumulation in the F2:3 families and overall QTL effects differed because of environmental conditions. Many of these loci were distinct from previously identified QTL, which confirmed Mp717 as a novel source of aflatoxin resistance.

Determining moisture levels in straw bale construction

The use of straw bales for the construction of buildings in the UK has to date generally been limited to the self-build fringe sector. In order to bring this form of construction into the mainstream sector, to benefit from its inherent low carbon and high insulation characteristics, it is necessary to guarantee the long-term durability of the straw. Maintaining low moisture levels is critical to the long-term resistance of straw to biological decomposition. This paper presents results from a study on moisture monitoring in straw bale construction, and includes the development of an empirical equation which relates straw moisture content to surrounding microclimate relative humidity and temperature. This knowledge allows continuous non-invasive condition monitoring of the straw in on-going research work and potentially as part of future managed maintenance of straw bale buildings.