Saturated Humidity Research Articles

Mapping molecular orientation in dry and wet Nephila clavipes dragline spider silk

The alignment of β-sheets within spider dragline silk fibers is an important factor in their tensile strength and extensibility. We are using linear dichroism of the C 1s → π*amide transition measured using scanning transmission X-ray microscopy (STXM) to generate quantitative maps of the <P2> orientation parameters with 30 nm spatial resolution. Here we have extended these measurements from dry samples to samples with partial or full hydration. A device for monitoring and controlling the humidity of a sample in the STXM is described and used to measure the effect of saturated humidity on a section of N. clavipes dragline spider silk. The microstructure and distributions of molecular orientation change considerably with hydration in ways consistent with the supercontraction observed in free standing dragline spider silk. The STXM results are compared to infrared and Raman microscopy results.

Ultrastructure and mineral distribution in the tergal cuticle of the terrestrial isopod Titanethes albus. Adaptations to a karst cave biotope

Composition and spatial distribution of organic and inorganic materials within the cuticle of isopods vary between species. These variations are related to the behaviour and habitat of the animal. The troglobiotic isopod Titanethes albus lives in the complete darkness of caves in the Slovenian Karst. This habitat provides constant temperature and saturated humidity throughout the year and inconsistent food supply. These conditions should have lead to functional adaptations of arthropod cuticles. However, studies on structure and composition of cave arthropod cuticles are rare and lacking for terrestrial isopods. We therefore analysed the tergite cuticle of T. albus using transmission and field-emission electron microscopy, confocal micro-Raman spectroscopic imaging, quantitative X-ray diffractometry, thermogravimetric analysis and atomic absorption spectroscopy. The ultrastructure of the epicuticle suggests a poor resistance against water loss. A weak interconnection between the organic and mineral phase within the endo- and exocuticle, a comparatively thin apical calcite layer, and almost lack of magnesium within the calcite crystal lattice suggest that the mechanical strength of the cuticle is low in the cave isopod. This may possibly be of advantage in maintaining high cuticle flexibility and reducing metabolic expenditures.

Interaction between malignant transformation of human pulmonary epithelial cells and activation of fibroblasts induced by Yunnan tin mine dust

To study the interaction between transformation of human pulmonary epithelial cells and activation of fibroblasts induced by Yunnan tin mine dust. (1) The immortalized human bronchial epithelial cell line BEAS-2B and human embryo lung fibroblast cell line WI-38 were grown in MEM medium containing 5% and 10% FBS, respectively, at 37 degrees C and 5% CO2 with saturated humidity. The cells were subcultured every 6 days. BEAS-2B cells and WI-38 cells were induced with Yunnan tin mine dust on every other generation at the concentration of 100 microg/ml. From the 11th generation, the cells were co-cultured. Epithelial cell transformation was tested using concanavalin A (ConA) agglutination and anchorage-independent growth assays. The cell cycles were analyzed through flow cytometry. The expressions of alpha-SMA in fibroblasts were determined with immunocytochemistry. (1) Cell morphology of mine dust-exposed epithelial cells began to transform at the 28th generation. Similar transformations were observed with mine dust-induced epithelial cells co-cultured with fibroblasts from the 20th generation and mine dust-induce epithelial cells co-cultured with mine dust-induced fibroblasts from the 16th generation. ConA agglutination assay and anchorage-independent growth assays were negative in normal BEAS-2B cells. At the 26 th generation, the agglutination test result of the mine dust-exposed epithelial cells was positive. Co-cultured with fibroblasts and mine dust-exposed fibroblasts, the agglutination time of the mine dust-exposed epithelial cells became short. Epithelial cell anchorage-independent growth assay was positive for mine dust-exposed epithelial cells co-cultured with fibroblasts at the 36th generations and for mine dust-exposed epithelial cells co-cultured with mine dust-exposed fibroblasts at the 26th generations. The clone formation rate of the 26th generation was 6.00 per thousand +/- 1.00 per thousand and 15.33 per thousand +/- 2.52 per thousand respectively, with the significant differences (P < 0.05). With generation adding, the portion of S phase increased for mine dust-exposed epithelial cells. (2) At the 26th generations, fibroblasts expressed alpha-SMA. Co-cultured with epithelial cell, the alpha-SMA expression of fibroblasts increased. Especially, positive cell numbers and intensity of staining dramatically increased with generation adding. (1) The tin mine dust can induce malignant transformation of human pulmonary epithelial cells BEAS-2B and activation of fibroblasts WI-38. (2) The epithelial cells are major target in carcinogenesis induced by Yunnan tin mine dust. (3) Transformation of epithelia and activation of fibroblasts co-evolve in the developing process of induced lung cancer by Yunnan tin mine dust.

First Report of Dry Rot Caused by Fusarium oxysporum on Rose (Rosa spp.) in Brazil.

Roses are a high-value niche crop in the higher altitudes of northeastern Brazil. From July of 2007 and throughout 2008, severe stem rot and wilting of rose seedlings were observed in commercial fields in the São Benedito District, Ceará State, Brazil. Although economic losses due to the disease are unknown, it poses a threat to the growing rose industry in that region. Symptoms included leaf yellowing and abscission followed by plant collapse. Symptoms appeared earlier when grafted seedlings were produced during periods of high relative humidity (80 to 98%) and warm temperatures (20 to 31°C). In the laboratory, symptomatic seedlings were rinsed with distilled water, surface sterilized with 0.5% NaOCl, and incubated on PDA at 26 ± 2°C. Fusarium oxysporum was consistently isolated from infected scions and rootstocks. Identification of F. oxysporum was based on colony and conidia morphology obtained from single-spore colonies. Five 4-week-old rose ('Carola') seedlings were inoculated with a culture of fungus by spraying the needle-wounded scion with a spore suspension (1 × 105 CFU/ml). The spore suspension was obtained from a 1-week-old PDA culture incubated at 26 ± 2°C. Control seedlings were sprayed with sterile water. Inoculated seedlings were incubated for the first 48 h in a saturated humidity chamber. After 20 days at room temperature, the scion tissue of inoculated seedlings turned necrotic. Two symptomatic seedlings were placed in a saturated humidity chamber for 24 h to determine if fungal sporulation could be observed on the surface of the tissue. After 5 to 7 days, a white mycelium was observed over the necrotic tissue. Seedlings sprayed with sterile water remained symptomless. F. oxysporum was reisolated from symptomatic tissue. An isolate of F. oxyporum (No. 1484) was deposited in the Mycology Collection of Lavras (Minas Gerais State, Brazil). To our knowledge, this is the first report of F. oxysporum causing a disease on rose seedlings in Brazil.

Effect of recombinant gonadotropins on embryo quality in superovulated rabbit does and immune response after repeated treatments

This study aimed first to evaluate the effect of recombinant human FSH (rhFSH) with and without recombinant human LH (rhLH) on fresh and frozen-thawed embryo development and also to analyze the immune response of rabbit does (Oryctolagus cuniculus) subjected to repeated rhFSH treatments. Nulliparous New Zealand White does were used. In Experiment 1, 120 does were superovulated with 25 IU rhFSH alone or in combination with 5% or 10% rhLH (1.25 IU or 2.50 IU rhLH). A total of 1116 embryos at the compacted morula stage were cultured at 38.5 °C, 5% CO 2, and saturated humidity for 48 h. The embryo development to hatching blastocyst was significantly lower for the group with 10% rhLH versus that of the control group (65.6 vs. 79.5 for rhFSH + 10% rhLH vs. control, respectively). However, no significant difference was found in development to hatching blastocyst for the control, rhFSH alone, and rhFSH + 5% rhLH groups. The developmental potential of frozen-thawed embryos obtained from all groups was similar, with an 83.5% in vitro development rate until the expanded blastocyst stage. To detect anti-FSH antibodies, in Experiment 2, does were subject to four superovulation treatments. The hormone administration had a significant effect on immune response in the superovulation group after two treatments (0.14 ± 0.074 and 0.15 ± 0.076 vs. 0.46 ± 0.078 and 0.50 ± 0.078 optical density for the first, second, third, and forth cycles, respectively). Nevertheless, none of the treated does had an immune response in both the first and second treatments; on the contrary, a significant increase in the antibody levels was observed in these females at the moment of the third and fourth superovulation treatments. In conclusion, rhFSH superovulation treatments increase the reproductive potential of rabbit does.

Artificial miniaturization causes eggs laid by crowd-reared (gregarious) desert locusts to produce green (solitarious) offspring in the desert locust, Schistocerca gregaria

The mechanism underlying the phase-dependent polyphenism in hatchling body coloration was studied by testing for a possible causal relationship with egg size in the desert locust, Schistocerca gregaria. Crowd-reared (gregarious) females typically produce large, black offspring, whereas females reared in isolation (solitarious) deposit small, green offspring. We first tested for possible genetic differences in the role of egg foam by washing or separating eggs from two strains of locust. No solitarizing effect was found in either of the strains tested, supporting a previous finding, using another laboratory strain, to show that the hatchling body coloration and size are pre-determined in the ovary of the mother and no egg foam factor is involved in the control of the hatchling body coloration. Topical application of fenoxycarb, a juvenile hormone analog (JHA), and implantation of extra corpora allata (CA), taken from Locusta migratoria, caused gregarious female adults of S. gregaria to produce small eggs. Some eggs laid by CA-implanted females produced green hatchlings. All large eggs chosen among those deposited by gregarious females produced black hatchlings. When eggs were either kept on dry filter paper at nearly saturated relative humidity during embryogenesis or pricked with a needle so that some egg yolk was squeezed out, some produced small, green hatchlings. These results suggested that the amount of egg yolk or the availability of yolk material may determine the body coloration of hatchlings.

A three-dimension In Vitro Human Model of Hemangioma and initial application

Objective To create a three dimension(3D) in vitro model for angiogenesis of he-mangioma and to make initial use of the model. Methods A small fragment of hemangioma biopsy is em- bedded in fibrin gel in a well of culture plates and incubated in a serum-free, buffered-sah, minimal medi-um to set up the three-dimesnsion(3D) in vitro model for angiogenesis of hemangioma. The model is cul-tured in the culture box of 5% CO2,37℃ and saturated humidity. And pingyannycin as an interference factor is used to observe its effect of blood vessels. We observed the model by photics microscope and fluo-rescence microscope and HE staining. Results In the model ,a complex network of microvessels grows out from the 3 tissue fragments from the day 4th to 7th day after culture,and on the 8th to 10th day after cul-ture a compact network of microvessels come into being and micmvessels furcating and crossoverring,then tending to be stationary. Microvessels grow slowly to stagnate on the llth to 14th day after culture. The compact network around the tissue fragment was confirmed to be blood vessels by immunohistochemistry and electron microscopy. Micmvessels grow fastly to stagnate after 1 day to 2 day putting pingyangmycin in- to the model. The expression of the factor Ⅷ associated antigen was positive in the microvessels analyzed by SP immunohistochemistry. The cells in the microvessels were the vascular endothelial cells observed by transmission electron. Conclusion This model represented the in vivo status of hemangioma partly and could be an acceptable model for in vitro study. However, it has the disadvantages of unstable growth rate and regression time. Therefore,this model can not fully reflect the in vivo human hemangioma and further study needs to be carried out for establishing better model for investigation. Key words: Hemangioma; Angiogenesis; Culture ; Model

Comparative Tolerances of Various Beauveria bassiana Isolates to UV-B Irradiation with a Description of a Modeling Method to Assess Lethal Dose

The tolerances of 20 Beauveria bassiana isolates derived from host insects worldwide to UV-B irradiation were assessed quantitatively in multi-dose bioassays. Conidial suspensions of the isolates smeared on glass slides were exposed to the gradient UV-B doses of 0.1-1.6 J cm(-2) (D), which generated from 0.75 to 10.17 min irradiation of weighted 312-nm wavelength at 2.0-2.61 mW cm(-2). Irradiated conidia were then incubated for 24 h at 25 degrees C under saturated humidity. The ratio of germination at each dose over that in the blank control was defined as survival index (I (s)). For all isolates, the I (s) - D observations fit well with the survival model I (s) = 1/[1 + exp(a + bD)] (0.94 < or = r (2) < or = 0.99) generated widely spanned lethal doses of 0.154-0.928, 0.240-1.139, and 0.383-1.493 J cm(-2) for their losses of 50%, 75%, and 95% viabilities, respectively. These were far below the solar UV-B dose of 2.439 J cm(-2) measured in a sunny day during the summer. The large variation of UV-B tolerance among the isolates indicates a necessity to select UV-tolerant candidates for formulations applied to insect control during summer. The highly efficient bioassay method was developed to measure accurately the UV-B tolerances of fungal biocontrol agents as lethal doses.

Measurement and Characterization of the Moisture-Induced Properties of ACF Package

This study is to observe the exact behavior of anisotropic conductive adhesion (ACF) package under humid environments by obtaining the moisture-induced properties such as diffusion coefficient (the rate of moisture movement into the materials), saturated moisture content (the maximum absorbed quantity), and swelling coefficient (length change due to the chemical interaction). So the experiments were performed to get the moisture-induced properties of ACF and FR4 using newly developed method at various temperature and relative humidity conditions. Experimental results showed that the diffusion coefficient of ACF and FR4 follows Arrhenius’ equation very well, and the saturated moisture content of them follows Henry’s law, which means linear relationship between saturated moisture content and relative humidity, but the saturated moisture content of ACF is influenced by temperature as well as relative humidity. And the swelling coefficient of ACF and FR4 increases with temperature. Especially in the case of ACF, it shows the dramatic degradation due to Tg (glass transition temperature) at nearby 85°C. Finally, as using these experimental results, the behavior of the ACF package under humid environment is predicted through finite element simulation. When wetness defined by moisture content over saturated moisture content changes from 0 to 0.9, the center of the ACF package is subject to compression and the edge of the ACF package is subject to tension in the case of transient state. After all, because the edge of the ACF package is very weak due to bending moment, the failure is easy to occur under humid environment.

Abiotic and biotic degradation of oxo-biodegradable polyethylenes

Conventional polymeric materials accumulate in the environment due to their low biodegradability. However, an increase in the biodegradation rate of these polymers may be obtained with the addition of pro-degrading substances. This study aimed to evaluate abiotic and biotic degradation of polyethylenes (PEs) using plastic bags of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) formulated with pro-oxidant additives as test materials. These packaging materials were exposed to natural weathering and periodically analyzed with respect to changes in mechanical and structural properties. After a year of exposure, residue samples of the bags were incubated in substrates (compost of urban solid waste, perlite and soil) at 58 °C and at 50% humidity. The biodegradation of the materials was estimated by their mineralization to CO 2. The molar mass of the pro-oxidant-activated PE decreased and oxygen incorporation into the chains increased significantly during natural weathering. These samples showed a mineralization level of 12.4% after three months of incubation with compost. Higher extents of mineralization were obtained for saturated humidity than for natural humidity. The growth of fungi of the genera Aspergillus and Penicillium was observed on PE films containing pro-oxidant additives exposed to natural weathering for one year or longer. Conventional PE films exposed to natural weathering showed small biodegradation.

Adaptive plasticity of killifish (Fundulus heteroclitus) embryos: dehydration-stimulated development and differential aquaporin-3 expression

Embryos of the marine killifish Fundulus heteroclitus are adapted to survive aerially. However, it is unknown if they are able to control development under dehydration conditions. Here, we show that air-exposed blastula embryos under saturated relative humidity were able to stimulate development, and hence the time of hatching was advanced with respect to embryos continuously immersed in seawater. Embryos exposed to air at later developmental stages did not hatch until water was added, while development was not arrested. Air-exposed embryos avoided dehydration probably because of their thickened egg envelope, although it suffered significant evaporative water loss. The potential role of aquaporins as part of the embryo response to dehydration was investigated by cloning the aquaporin-0 (FhAqp0), -1a (FhAqp1a), and -3 (FhAqp3) cDNAs. Functional expression in Xenopus laevis oocytes showed that FhaAqp1a was a water-selective channel, whereas FhAqp3 was permeable to water, glycerol, and urea. Expression of fhaqp0 and fhaqp1a was prominent during organogenesis, and their mRNA levels were similar between water- and air-incubated embryos. However, fhaqp3 transcripts were highly and transiently accumulated during gastrulation, and the protein product was localized in the basolateral membrane of the enveloping epithelial cell layer and in the membrane of ingressing and migrating blastomers. Interestingly, both fhaqp3 transcripts and FhAqp3 polypeptides were downregulated in air-exposed embryos. These data demonstrate that killifish embryos respond adaptively to environmental desiccation by accelerating development and that embryos are able to transduce dehydration conditions into molecular responses. The reduced synthesis of FhAqp3 may be one of these mechanisms to regulate water and/or solute transport in the embryo.

Evaluation of a satellite-derived latent heat flux product in the South China Sea: A comparison with moored buoy data and various products

Latent heat flux in the South China Sea (SCS) mainly based on the Tropical Rain Measuring Mission Microwave Imager (TMI) is compared with the Objectively Analyzed air-sea heat Fluxes (OAFlux), the Goddard Satellite-Based Surface Turbulent Fluxes, version 2 (GSSTF2), the Japanese Ocean Flux Data Sets with use of Remote Sensing Observations (J-OFURO), the European Centre for Medium-Range Weather Forecasts (ECMWF), the National Centers for Environmental Prediction/Department of Energy reanalysis 2 (NCEP2), and International Comprehensive Ocean-Atmosphere Data Set data (ICOADS). These products did not all compare well to in situ data. It is found that TMI latent heat flux and OAFlux approximately reproduce the time variations of buoy data. However, ECMWF and ICOADS were found that had moderate systematic errors with respect to in situ data. All products qualitatively reveal a similar pattern in climatological fields. Although the satellite-derived products are quite similar, TMI latent heat is smaller than those of OAFlux, GSSTF2 and J-OFURO in the northern SCS. The difference between TMI latent heat and ICOADS is large, and the temporal correlation is extremely low in the entire basin except the Luson Strait. This is owned to that the ICOADS hardly reproduces accurate variability in the data-sparse regions. Also the temporal cross-correlation coefficients of between TMI latent heat and ECMWF or NCEP2 are considerably lower in the central SCS, may be affected by the lack of ship observations of ECMWF and NCEP2 there. The present study also compares meridional structures of the zonal averaged latent heat. The TMI latent heat and OAFlux overestimate the other two satellite-derived products during summer, whereas in winter, the TMI latent heat underestimates the other products in the northern regions. Though the examination of the influence of input variables, we note that the underestimation of TMI latent heat flux than other three satellite derived products in the northern region is mainly caused by larger near-surface air humidity there. While, large sea surface saturation humidity contributes to larger ECMWF latent heat flux. On the other hand, lager latent heat flux of NCEP2 in central parts and ICOADS in eastern bands is possibly mainly caused by the difference in winds.

212 EFFECTS OF VASCULAR ENDOTHELIAL GROWTH FACTOR ON THE EARLY DEVELOPMENT AND POLYSPERMY RATE OF OVINE EMBRYOS PRODUCED IN VITRO

To investigate the effect of vascular endothelial growth factor (VEGF) on the early development and polyspermy rate of ovine embryos in vitro, 2 experiments were conducted with human recombinant VEGF165 supplemented to the media during maturation, fertilization, and culture in vitro, respectively. Ovaries were collected from ewes at a local slaughterhouse. All oocytes surrounded by a multilayer of cumulus cells were collected and rinsed 3 times in maturation medium (control medium and treatment medium, respectively). A total of 100 oocytes in each group were cultured in 4-well plates (Nunc) containing 800 μL of maturation medium at 38.5°C in an atmosphere of 5% CO2 with saturated humidity. Four replicates of each experiment were conducted. Statistical analyses were conducted by ANOVA with SPSS 12.0 software (SPSS Inc., Chicago, IL, USA). Data are expressed as means, and P &lt; 0.05 was considered significant. In Experiment 1, to investigate the effect of VEGF on the early development of ovine embryos in vitro, VEGF was used at 5 ng mL–1 (treatment group A) and 10 ng mL–1 (treatment group B) in maturation medium (TCM-199 + BSA), HSOF fertilization medium, and SOF culture medium. The results showed that the maturation rate was increased significantly (P &lt; 0.01), from 75.76% in the control treatment to 83.98 and 80.23% in treatment group A and treatment group B, respectively. The cleavage rate was increased from 75.85% in the control group to 79.39% in treatment group A (P &gt; 0.05). The development rates of morulae (45.03%) and blastocysts (23.54%) in treatment group A were significantly higher (P &lt; 0.01) than those in the control group (38.94 and 18.09%, respectively). In addition, the development rates of blastocysts in treatment group B (21.05%) were lower than those in treatment group A (P &gt; 0.05) and higher than those in the control group (P &gt; 0.05). In Experiment 2, to investigate the effect of VEGF on the polyspermy rate of ovine embryos in vitro, 5 ng mL–1 of VEGF was used in TCM-199 + BSA maturation medium in this experiment. The results showed that the fertilization rate after 18 h of IVF was increased significantly (P &lt; 0.01), from 75.75% in the control group to 83.86% in the treatment group, and that the polyspermy rate was decreased significantly (P &lt; 0.01), from 12.64% in the control group to 7.68% in the treatment group. These results indicate that VEGF significantly improved the maturation and fertilization rates of ovine oocytes and, consequently, the rate of embryo development in vitro, especially when the medium was supplemented with 5 ng mL–1 of VEGF. The VEGF obviously decreased the polyspermy rate and bated the phenomenon of polyspermy in the process of ovine oocyte IVF. The present study was supported by the National Natural Science Foundation of China (No. 30371035).

Water-Induced Degradation of Polymer Solar Cells Studied by H218O Labeling

Water-induced degradation of polymer photovoltaics based on the active materials poly(3-hexylthiophene) (P3HT) or poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) was studied. The solar cell devices comprised a bulk heterojunction formed by the active material and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in a standard device geometry. The use of H2(18)O in conjunction with time-of-flight secondary ion mass spectrometry enabled mapping of the parts of the device that were induced by water. A comparison was made between the two active materials and between devices that were kept in the dark and devices that had been subjected to illumination under simulated sunlight. Devices that were exposed to ambient humidity were compared to devices exposed to saturated humidity. Finally, a comparison was made between results obtained using H2(18)O and earlier work involving 18O2. Water was found to have behavior similar to but not identical with molecular oxygen.

Pathogen‐tested material of grapevine varieties and rootstocks

Pathogen‐tested material of grapevine varieties and rootstocks

Temporal Variability in Soil CO 2 Emission in an Orchard Forest Ecosystem

Temporal variability in soil CO 2 emission from an orchard was measured using a dynamic open-chamber system for measuring soil CO 2 efflux in Heshan Guangdong Province, in the lower subtropical area of China. Intensive measurements were conducted for a period of 12 months. Soil CO 2 emissions were also modeled by multiple regression analysis from daily air temperature, dry-bulb saturated vapor pressure, relative humidity, atmospheric pressure, soil moisture, and soil temperature. Data was analyzed based on soil moisture levels and air temperature with annual data being grouped into either hot-humid season or relatively cool season based on the precipitation patterns. This was essential in order to acquire simplifled exponential models for parameter estimation. Minimum and maximum daily mean soil CO 2 efflux rates were observed in November and July, with respective rates of 1.98 ± 0.66 and 11.04 ± 0.96 μmol m −2 s −1 being recorded. Annual average soil CO 2 emission ( F CO 2) was 5.92 μmol m −2 s −1. Including all the weather variables into the model helped to explain 73.9% of temporal variability in soil CO 2 emission during the measurement period. Soil CO 2 efflux increased with increasing soil temperature and soil moisture. Preliminary results showed that Q 10, which is deflned as the difierence in respiration rates over a 10 °C interval, was partly explained by flne root biomass. Soil temperature and soil moisture were the dominant factors controlling soil CO 2 efflux and were regarded as the driving variables for CO 2 production in the soil. Including these two variables in regression models could provide a useful tool for predicting the variation of CO 2 emission in the commercial forest soils of South China.

Spray evaporation of liquid foods

‘Spray evaporation’ based on the principle of adiabatic humidification was examined as an evaporation technique for the concentration of two types of representative liquid foods, namely, fruit juice and milk. The concentration of apple juice could be increased from 10.0 to 13.0 °Brix by this technique without application of heat utilizing the humidity potential to an extent of 89%. Employing heated process air during processing increased the amount of water evaporation owing to increased saturation humidity level, enabling higher concentrations to be achieved in apple juice (48 °Brix), reconstituted milk (29 °Brix) and single toned milk (22 °Brix). Feed flow rate had an inverse effect on the final concentration under otherwise similar conditions. Evaporative cooling associated with spray evaporation actually delivered the concentrate at a relatively lower temperature. By manipulating the operating conditions, humidity potential could be utilized to the extent of 55% with heated process air. The spray evaporation technique seemed to have a good potential for the concentration of liquid foods.

Measurements and estimates of leaf wetness over agricultural grassland for dry deposition modeling of trace gases

Leaf wetness is an important and frequent phenomenon for the surface–atmosphere exchange of some atmospheric trace gases that are well soluble in water, such as ammonia (NH 3 and SO 2), as well as for plant disease epidemiology. This study shows a comparison of two different techniques to measure leaf wetness; namely a painted flat-plate grid sensor and a system of four clip sensors. Although both techniques gave comparable results, the flat-plate grid sensor was favored, because of its stable signal and its ease of use. In this technique, the measurement height turned out to be of great importance for the leaf wetness duration (LWD); the flat-plate sensor at 1.0 m systematically underestimated LWD, while the flat-plate sensor at 0.1 m better represented the actual LWD. To obtain a representative signal, leaf wetness should be measured close to the surface. Using the available leaf wetness measurements, a comparison was made between three physical and four empirical leaf wetness models. Without any optimization, the physical model that calculates the potential condensation at the leaf surface gave the best results. However, after optimizing the humidity thresholds in the empirical leaf wetness models, the optimized model based on the difference between the actual and saturated specific humidity at the surface gave best results. For practical applications in atmospheric transport models, like for the calculation of dry deposition of well-soluble gases, the relative humidity (RH) threshold model might be easiest to implement. This study showed that different thresholds should be used for different vegetation types. In this study, an optimized RH threshold of 71% was derived for agricultural grassland.

Planar array stack design aided by rapid prototyping in development of air-breathing PEMFC

The polymer electrolyte membrane fuel cell (PEMFC) is one of the most important research topics in the new and clean energy area. The middle or high power PEMFCs can be applied to the transportation or the distributed power system. But for the small power application, it is needed to match the power requirement of the product generally. On the other hand, the direct methanol fuel cell (DMFC) is one of the most common type that researchers are interested in, but recently the miniature or the micro-PEMFCs attract more attention due to their advantages of high open circuit voltage and high power density. The objective of this study is to develop a new air-breathing planar array fuel cell stacked from 10 cells made by rapid prototyping technology which has potential for fast commercial design, low cost manufacturing, and even without converters/inverters for the system. In this paper, the main material of flow field plates is acrylonitrile–butadiene–styrene (ABS) which allows the fuel cell be mass-manufactured by plastic injection molding technology. The rapid prototyping technology is applied to construct the prototype and verify the practicability of the proposed stack design. A 10-cell air-breathing miniature PEMFC stack with a volume of 6 cm × 6 cm × 0.9 cm is developed and tested. Its segmented membrane electrode assembly (MEA) is designed with the active surface area of 1.3 cm × 1.3 cm in each individual MEA. The platinum loading at anode and cathode are 0.2 mg cm −2 and 0.4 mg cm −2, respectively. Results show that the peak power densities of the parallel connected and serial connected stack are 99 mW cm −2 at 0.425 V and 92 mW cm −2 at 4.25 V, respectively under the conditions of 70 °C relative saturated humidity ( i.e., dew point temperature), ambient temperature and free convection air. Besides, the stack performance is increased under forced convection. If the cell surface air is blown by an electric fan, the peak power densities of parallel connected and serial connected stack are improved to 123 mW cm −2 at 0.425 V and 105 mW cm −2 at 5.25 V, respectively. The forced convection air can not only increases the oxygen diffusion rate at the air-breathing surface, but also enhance the uniformity of output voltage distribution. The performance obtained in this work reaches to the state-of-the-air of air-breathing planar PEMFC stack comparing to recent literatures. In this study, the different behavior of output performance at water-rich region and water-lean region is also discussed.

Effect of temperature and growth media on the attachment of Listeria monocytogenes to stainless steel

Listeria monocytogenes ATCC 19111 cultivated in nutrient-rich medium (brain heart infusion, BHI) or starved in minimal medium (10% filter sterilized pond water and 90% sterilized distilled water) were investigated for their initial attachment to austenitic stainless steel No. 4 with satin finish at 4 °C, 20 °C, 30 °C, 37 °C, or 42 °C. A droplet (10 μl) containing ∼ 10 7 CFU/ml of L. monocytogenes suspended in BHI or minimal medium was placed on the stainless steel surface. After holding in saturated humidity for 3 h at the desired temperature the surface was washed and prepared for scanning electron microscopy (SEM). Using SEM, attachment of L. monocytogenes was determined by counting cells remaining on the surface. When L. monocytogenes cultivated in BHI were used, with the exception of the number of attached cells being lower at 42 °C than at 37 °C and 30 °C, the number of attached cells increased with increasing temperature ( P < 0.05). When L. monocytogenes starved in minimal medium were used, the number of attached cells also increased with increasing attachment temperature ( P < 0.05), but the number of attached cells at 42 °C was lower than that at the other temperatures. The attachment of L. monocytogenes to stainless steel surface was greater when cultivated in rich medium of BHI vs starved in the minimal medium.