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Processes based on electrostatic projection are used extensively in industry, e.g., for mineral separations, electrophotography, or manufacturing of coated abrasives, such as sandpaper. Despite decades of engineering practice, there are still unanswered questions. In this paper, we present a comprehensive experimental study of the projection process of more than 1500 individual spherical alumina particles with a nominal size of $500\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{m}$, captured by high-speed video imaging and digital image analysis. Based on flight trajectories of approximately 1100 projected particles, we determine the acquired charge and dynamics as a function of the relative humidity (RH) and the electric field intensity and compare the results with classical theories. For RH levels of 50% and above, more than 85% of distributed particles are projected, even when the electric field intensity is at its minimum level. This suggests that, beyond a critical value of the electric field intensity, the RH plays a more critical role in the projection process. We also observe that the charging time is reduced dramatically for RH levels of 50% and above, possibly due to the buildup of thin water films around the distributed particles, which can facilitate charge transfer. In contrast, projected particles at the 30% RH level exhibit excessive amounts of electric charge, between 2 and 4 times than that of the saturation value, which might be attributed to triboelectric charging effects. Finally, the physics of electrostatic projection is compared and contrasted with those of induced-charge electrokinetic phenomena, which share similar field-square scaling, as the applied electric field acts on its own induced charge to cause particle motion.

The objective of this study was to evaluate the effects of geographical location, crop type, and residue coverage on soil microbial assemblages in Sherm soil from 30 geographically separate commercial fields in Ochiltree and Moore Counties of Texas. Crop residue coverage was derived from spectral data and used to classify sorghum and wheat fields into high and low crop residue categories. Denaturing gradient gel electrophoresis-polymerase chain reaction (DGGE-PCR) assays employing universal PCR primers that target prokaryotic and eukaryotic ribosomal genes were used to evaluate microbial community structure. An interaction between geographical location, crop type, and crop residue coverage was observed. A 50% similarity level was observed for overall bacterial community structure as determined using 16S data while a 59% similarity was observed for overall fungal community structure using 18S data. For the 16S composite dataset, high overall rates of correct classification (ORCC) were observed based on the user-defined groups of county by crop by residue coverage. A similar result was observed for fungal community structure using primer set FR1GC-FF390. Our data support the hypothesis that there are multiple provinces and multiple habitats that govern the assemblage of free-living taxa within the Moore–Ochiltree County agroecosystem. An ancient microbial assemblage based on historical features was identified and is still visible despite the presence of different crop types and cropping systems (Conventional vs. Conservation). For sorghum and wheat grown in Moore and Ochiltree Counties, a two-province state (Moore and Ochiltree Counties) was defined comprised of four habitats i.e. sorghum and wheat habitats influence by degree of residue coverage. Crop type and residue coverage can affect microbial assemblages within a geographical context.

Cattle feedyards can impact local environments through emission of ammonia and dust deposited on nearby land. Impacts range from beneficial fertilization of cropland to detrimental effects on sensitive ecosystems. Shortgrass prairie downwind from an adjacent feedyard on the southern High Plains of Texas, USA changed from perennial grasses to annual weeds. It was hypothesized that N enrichment from the feedyard initiated the cascade of negative ecological change. Objectives were to determine the distribution of soil nitrogen and estimate N loading to the pasture. Soil samples were collected from 119 locations across the pasture and soil total N (TN), nitrate-N and ammonium-N (AN) determined in the top 30 cm. Soil TN concentration decreased with distance downwind from the feedyard from 1.6 ± 0.2 g kg−1 at 75 m to 1.2 ± 0.05 g kg−1 at 582 m. Nitrate-N concentration decreased within 200 m of the feedyard and changed little at greater distances. Ammonium-N concentration decreased linearly (P < 0.001) with increasing distance from the feedyard from 7.9 ± 1.7 mg kg−1 within 75 m from the feedyard to 5.8 ± 1.5 mg kg−1 at more than 550 m from the feedyard; however, distance only explained 12% of the variability in AN concentration. Maximum nitrogen loading, from 75 to 106 m from the feedyard, was 49 kg ha−1 year−1 over 34 years and decreased with distance from the feedyard. An estimate of net dry deposition of ammonia indicated that it contributed negligibly to N loading to the pasture. Nitrogen enrichment that potentially shifted vegetation from perennial grasses to annual weeds affected soil N up to 500 m from the feedyard; however, measured organic and inorganic N beyond that returned to typical and expected levels for undisturbed shortgrass prairie.

The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is the most destructive insect pest of rice in the United States and is a particularly severe pest in Louisiana. The current management program for this insect in Louisiana relies heavily on insecticides, most notably the seed treatment fipronil (Icon). Diversification of the management program by incorporation of alternative strategies is needed to improve the effectiveness and long-term stability of the program. In the three experiments reported here, three components of a diversified management program for the rice water weevil in Louisiana--host plant resistance, treatment of seeds with Icon, aid the cultural practice of delayed flooding--were investigated. Comparison of the densities of weevil larvae on the roots of several commercial cultivars indicated that the long-grain cultivar 'Jefferson' was more resistant to infestation by the rice water weevil than the other cultivars. The medium-grain cultivars 'Bengal', 'Earl' and 'Mars' and the long-grain variety 'Cocodrie' were the most susceptible to infestation. Comparison of yield data from untreated plots and plots treated with Icon indicated that the long-grain cultivars Cocodrie, Lemont, and Jefferson were more tolerant of weevil injury than the other cultivars. A 2-wk delay in flooding was associated with yield benefits in plots not treated with Icon. Treatment of seeds with Icon controlled weevils in all three screening experiments. The implications of these results for the development of an integrated management program for the rice water weevil are discussed.

The rice water weevil, Lissorhoptrus oryzophilus Kuschel, has been managed for the past 30 yrs using the soil insecticide carbofuran. The recent cancellation of the registration for carbofuran in rice has necessitated a shift to management strategies involving other insecticides, including lambda-cyhalothrin, fipronil, and diflubenzuron. Efficacies and effects on population dynamics of three alternatives to carbofuran (lambda-cyhalothrin and diflubenzuron as foliar sprays and fipronil as a seed treatment) were compared in two water-seeded and one drill-seeded field trials. Applications of lambda-cyhalothrin, but not of diflubenzuron or fipronil, resulted in decreases in the densities of rice water weevil adults and eggs. All three insecticides suppressed larval densities to levels comparable to, or lower than, densities in plots treated with carbofuran. All three alternatives to carbofuran differed from carbofuran with respect to their effects on the population dynamics of weevil larvae. Lambda-cyhalothrin, diflubenzuron, and fipronil were more effective than carbofuran at preventing early larval infestation of rice roots, but were less effective at preventing later infestation of roots. Yields from plots treated with fipronil, diflubenzuron, and lambda-cyhalothrin were generally higher than yields from plots treated with carbofuran, probably because prevention of early injury to roots has a more beneficial impact than prevention of later injury. This study also provided evidence for the utility of early planting and delayed flooding for management of the rice water weevil.

A Beauveria bassiana isolate from the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), was evaluated as a conidial powder against 3 coleopteran pests of stored grain: the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); and the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Bioactivity of B. bassiana isolate 22292A was assessed on 3 types of food substrates (red flour beetle media, medium grain brown rice, and long grain rough rice) at 27°C and 60% RH. Adult mortality was 80–100% at the higher dosage levels for all insects tested on all media types at 21 d after treatment. Emergence of adult progeny on brown and rough rice was reduced by 83–99% at the 2 highest dosage level. The abrasive nature of rice hulls on the rough rice may contribute to the accelerated mortality seen on this medium.

The angulation of the sacrum is easily measured. The authors have previously reported on patients who were symptomatic with a diagnosis of myelomeningocele who were found to have changes in their lumbosacral angle (LSA) corresponding to the onset of symptoms indicative of a tethered spinal cord. The aim of this study was to verify this same finding in a group of patients with occult spinal dysraphism (that is, closed neural tube defect).A retrospective analysis of 50 consecutive lipomyelomeningocele repair procedures was performed. Data pertaining to 30 age-matched control patients were also analyzed. Measurements were made of the LSA over time in all studied patients harboring lipomyelomeningoceles. Appropriate imaging was available for 25 cases of lipomyelomeningocele (that is, radiographs of the lumbosacral junction were available from the patient's perinatal period and at presentation of symptoms of a tethered spinal cord). Roughly one third of these patients suffered symptoms from a tethered spinal cord at the most recent follow-up examination. Nine patients (36%) were found to have corresponding LSA measurements greater than 70 degrees, and seven (28%) of these patients presented with signs and symptoms of a tethered spinal cord, such as decreased lower-extremity function (two patients), urinary bladder incontinence (three patients), back pain (one patient), and lower-extremity paresthesias (one patient). The LSA measurements were statistically greater (p0.05) in the symptomatic patient population than in age-matched control patients and asymptomatic patients. Changes in the LSA in these symptomatic patients ranged from 5 to 24 degrees (mean 13 degrees). Changes in the LSA were noted in only two asymptomatic patients. No single sign or symptom of a tethered spinal cord appeared to correlate to any degree of increase in the LSA. Of the 25 patients excluded from this study because perinatal radiographic images were not available, none was symptomatic at the most recent follow-up examination and none had a grossly exaggerated LSA.Signs and symptoms indicative of a tethered spinal cord appear to correspond to increases in the LSA. Although the authors do not advocate the use of LSA measurement as the sole indicator of a tethered spinal cord, this imaging finding may prove useful to the clinician as an indication of the tethered spinal cord or as an adjunct in verifying symptomatology in patients harboring a lipomyelomeningocele.

Construction of permanent metal-molecule-metal (MMM) junctions, though technically challenging, is desirable for both fundamental investigations and applications of molecule-based electronics. In this study, we employed the nanotransfer printing (nTP) technique using perfluoropolyether (PFPE) stamps to print Au thin films onto self-assembled monolayers (SAMs) of alkanedithiol formed on Au thin films. We show that the resulting MMM junctions form permanent and symmetrical tunnel junctions, without the need for an additional protection layer between the top metal electrode and the molecular layer. This type of junction makes it possible for direct investigations into the electrical properties of the molecules and the metal-molecule interfaces. Dependence of transport properties on the length of the alkane molecules and the area of the printed Au electrodes has been examined systematically. From the analysis of the current-voltage (I-V) curves using the Simmons model, the height of tunneling barrier associated with the molecule (alkane) has been determined to be 3.5 ± 0.2 eV, while the analysis yielded an upper bound of 2.4 eV for the counterpart at the interface (thiol). The former is consistent with the theoretical value of ~3.5-5.0 eV. The measured I-V curves show scaling with respect to the printed Au electrode area with lateral dimensions ranging from 80 nm to 7 μm. These results demonstrate that PFPE-assisted nTP is a promising technique for producing potentially scalable and permanent MMM junctions. They also demonstrate that MMM structures (produced by the unique PFPE-assisted nTP) constitute a reliable test bed for exploring molecule-based electronics.

Background The high demand for ethanol in the U.S. has generated large stocks of wet distillers grains (DG), a byproduct from the manufacture of ethanol from corn and sorghum grains. Little is known, however, about the potential influence of dietary DG on fecal microbial community structure. A better understanding of the microbial population in beef cattle feces could be an important monitoring tool to facilitate goals of improving nutrient management, increasing animal growth performance and decreasing odors and/or shedding of pathogens. Five diets consisting of a traditional diet fed to finishing beef cattle in the Southern High Plains of Texas-CON (steam-flaked corn control with 0% DG), and four concentrations of DG in the dietary dry matter; 10 C (10% corn-based DG), 5S (5% sorghum-based DG), 10S (10% sorghum DG), and 15S (15% sorghum DG) were fed to steers at the Texas Tech University Burnett Animal Center. Diets were essentially isonitrogenous with a formulated crude protein value of 13.5%. Results Fecal grab samples were obtained from 20 steers (n = 4 per diet) and the barcoded DNA pyrosequencing method was used to generate 127,530 16S operational taxonomic units (OTUs). A total of 24 phyla were observed, distributed amongst all beef cattle on all diets, revealing considerable animal to animal variation, however only six phyla (core set) were observed in all animals regardless of dietary treatment. The average abundance and range of abundance, respectively of the core phyla were as follows: Firmicutes (61%, 19 to 83%), Bacteroidetes (28%, 11 to 63%), Proteobacteria (3%, 0.34 to 17.5%), Tenericutes (0.15%, 0.0 to 0.35%), Nitrospirae (0.11%, 0.03 to 0.22%), and Fusobacteria (0.086%, 0.017 to 0.38%). Feeding DG-based diets resulted in significant shifts in the fecal microbial community structure compared with the traditional CON. Four low abundance phyla significantly responded to dietary treatments: Synergistetes (p = 0.01), WS3 (p = 0.054), Actinobacteria (p = 0.06), and Spirochaetes (p = 0.06). Conclusions This is, to our knowledge, the first study using this method to survey the fecal microbiome of beef cattle fed various concentrations of wet DG. Comparison of our results with other cattle DNA sequencing studies of beef and dairy cattle feces from a variety of geographical locations and different management practices identifies a core set of three phyla shared across all cattle. These three phyla, in order of relative abundance are; Firmicutes, Bacteroidetes, and Proteobacteria. The presence of large animal-to-animal variation in cattle microbiome was noted in our study as well as by others.

Tests were conducted to determine whether seeds from the tropical plant Pentaclethra macroloba (C.L. Willdenow) O. Kuntze contain factors that retard or inhibit growth of larvae of Helicoverpa zea (Boddie). Three different assays were used to determine effects of aqueous seed extracts on H. zea . Micro-bioassays examined effects of extracts on living larvae. Cell culture assays examined effects of the seed extracts on H. zea cells. Midgut enzyme inhibition assays examined the potential of the extracts to disrupt H. zea larval digestive processes. These three assays showed that P. macroloba seeds contain factors that retard H. zea growth, reduce the viability of H. zea cells, and specifically inhibit the activity of trypsin and chymotrypsin proteinases from the larval midgut. In addition, dialysis and heat treatment indicated that the active, water-soluble factors in P. macroloba seeds have approximate molecular weights ≥3,500 and are heat-labile. Results from recovery studies indicated that H. zea larvae have a limited ability to overcome the toxic effects of the active water-soluble components of P. macroloba seeds.

The biological and chemical characteristics of feedyard pen surfaces have the potential to affect environmental conditions with respect to air and water quality. Little is known about feedyard pen surface chemistry and that of the underlying microbial community structure. The feedlot surface profile has been described as four layers: the unconsolidated (or loose surface), dry-pack, wet-pack, and soil layer. It was determined that NO3-N concentration was greater in the soil layer than in the manure layers whereas NH4-N concentration was greatest in the wet-pack layer. In this study, we characterized the microbial communities associated with these four feedlot layers using the DGGE-PCR method employing a suite of primers that target 16S and 18S rDNA. The distribution of microorganisms intimately involved in the cycling of N such as the ammonia-oxidizing bacteria (AOB) found within the Betaproteobacteria and the nitrite-oxidizing bacteria (NOB) found in the Alphaproteobacteria division was determined. The influence of the feedlot layers on microbial community structure was observed in the spatial grouping of DNA fingerprint patterns and as assessed by two indices of diversity. Different lineages of AOB were found to be associated with these feedlot layers which imply a microbial ecosystem that is uniquely influenced by the physical and chemical properties of these feedlot layers. Both AOB and NOB communities are present in all feedyard pen surface layers for nitrification of ammonia to occur. The wet-pack layer showed a marked reduction in both fungal diversity and evenness. A feedlot pen surface may be viewed as a distinct microbiological island.

ATP and its metabolites regulate vascular tone; however, the sources of the ATP released in vascular beds are ill defined. As such, we tested the hypothesis that all limbs of an extracellular purinergic signaling system are present in vascular endothelial cells: ATP release, ATP receptors, and ATP receptor-triggered signal transduction. Primary cultures of human endothelial cells derived from multiple blood vessels were grown as monolayers and studied using a bioluminescence detection assay for ATP released into the medium. ATP is released constitutively and exclusively across the apical membrane under basal conditions. Hypotonic challenge or the calcium agonists ionomycin and thapsigargin stimulate ATP release in a reversible and regulated manner. To assess expression of P2X purinergic receptor channel subtypes (P2XRs), we performed degenerate RT-PCR, sequencing of the degenerate P2XR product, and immunoblotting with P2XR subtype-specific antibodies. Results revealed that P2X4and P2X5are expressed abundantly by endothelial cell primary cultures derived from multiple blood vessels. Together, these results suggest that components of an autocrine purinergic signaling loop exist in the endothelial cell microvasculature that may allow for “self-regulation” of endothelial cell function and modulation of vascular tone.

Proteinases and peptidases from the intestinal tract of fifth-instar larvae of Heliothis (= Helicoverpa) zea (Boddie) (Lepidoptera:Noctuidae) were characterized based on their substrate specificity, tissue of origin, and pH optimum. Activity corresponding to trypsin, chymotrypsin, carboxypeptidases A and B, and leucine aminopeptidase was detected in regurgitated fluids, midgut contents, and midgut wall. High levels of proteinase activity were detected in whole midgut homogenates, with much lower levels being observed in foregut and salivary gland homogenates. In addition, enzyme levels were determined from midgut lumen contents, midgut wall homogenates, and regurgitated fluids. Proteinase activities were highest in the regurgitated fluids and midgut lumen contents, with the exception of leucine aminopeptidase activity, which was found primarily in the midgut wall. Larvae fed their natural diet of soybean leaves had digestive proteinase levels that were similar to those of larvae fed artificial diet. No major differences in midgut proteinase activity were detected between larvae reared under axenic or xenic conditions, indicating that the larvae are capable of digesting proteins in the absence of gut microorganisms. The effect of pH on the activity of each proteinase was studied. The pH optima for the major proteinases were determined to be pH 8.0-8.5 for trypsin, when tosyl-L-arginine methyl ester was used as the substrate; and pH 7.5-8.0 for chymotrypsin, when benzoyl-L-tyrosine ethyl ester was used as the substrate.

The structures of polymers formed when alkali metals are placed in the vapor phase above isoprene monomer, both in the presence and absence of carbon dioxide, were investigated. In the absence of carbon dioxide, the polymers were all gel-like and soluble. In the presence of carbon dioxide, however, insoluble popcorn polymers were formed. The structures of the soluble polymers varied from primarily cis in the case of lithium to trans for sodium and potassium initiation. In the presence of carbon dioxide the three alkali metals produced polymers having similar structures, predominantly trans. In the absence of carbon dioxide most of the polymerization proceeds anionically with the majority of the free radical sites of the initially formed radical anion being removed by a transfer reaction or by dianion formation. The presence of carbon dioxide, however, leads to the formation of car boxy late ions that prevent anionic polymerization. Then, due to the structural orientation of the radical anion on t...

A three year continuous corn experiment was conducted to evaluate the use of soil nitrate nitrogen determination as a means of modifying nitrogen recommendations for corn. Three rates of nitrogen (84, 168, 252 kg/ha) were used. Nitrate nitrogen contents of the soil profile to 60 cm depth were determined several times over the three year period. The rainfall distribution and crop demand for N appeared to have the greatest effect on soil nitrate levels at any given sampling. Quantity of nitrate nitrogen in the soil profile near planting of corn had no significant effect on corn grain yields. The analyses of samples showed seasonal and treatment changes. There were some significant carryover effects on corn yields but these effects were not measurable using only soil nitrate analysis. Coefficients of variation for the nitrate measurements went as high as 100% and were not due to laboratory procedures. The sample variability, difficulty of sampling and lack of relationship of results to corn yields m...

The paper examines economics of the solid rocket booster for the Space Shuttle. Costs have been held down by adapting existing technology to the 146 in. SRB selected, with NASA reducing the cost of expendables and reusing the expensive nonexpendable hardware. Drop tests of Titan III motor cases and nozzles proved that boosters can survive water impact at vertical velocities of 100 ft/sec so that SRB components can be reused. The cost of expendables was minimized by selecting proven propellants, insulation, and nozzle ablatives of known costs; the propellant has the lowest available cost formulation, and low cost ablatives, such as pitch carbon fibers, will be used when available. Thus, the use of proven technology and low cost expendables will make the SRB an economical booster for the Space Shuttle.

THE head of the Department of Music at Baker University, Baldwin, Kansas, presents a startling picture of “vocal errors” which he feels are being encouraged-or at least tolerated-in some high schools today.

Regulation of transcription within four well-defined regions of the DNA genome of the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV) was studied in a permissive lepidopteran cell line. Spodoptera frugiperda IPLB-SF-21 and a nonpermissive dipteran cell line, Drosophila melanogaster DL-1. Cycloheximide, an inhibitor of protein synthesis, was used to identify immediate early transcripts and aphidicolin, an effective inhibitor of DNA replication, was used to distinguish early and late transcripts in S. frugiperda cells. Immediate early transcripts were identified in the HindIII-K (85 to 87.5%), the HindIII-I/EcoRI-F (I/F from 35 to 37%) and the HindIII-P/EcoRI-P (p10 from 88.5 to 89.5%) regions of the genome. Late RNAs, defined by their sensitivity to aphidicolin as well as cycloheximide, overlapped the immediate early RNAs. Specific viral transcripts were synthesized in nonpermissive D. melanogaster cells infected with AcNPV but late viral transcripts were not observed.