bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transport of Giardia and Manure Suspensions in Saturated Porous Media
Authors: Bradford Scott A. , Tadassa Yadata F. , Pachepsky Yakov 
Published: April 2006

ABSTRACTExperiments were conducted to elucidate the transport behavior of cysts of Giardia and manure suspensions through several aquifer sands. Decreasing the median grain size of the sand resulted in lower peak effluent concentrations and increased deposition of the Giardia and manure particles in the sand near the column inlet. The effluent concentration curves for the manure suspensions also exhibited asymmetric shapes that tended to include larger particle sizes as the manure suspension was continuously added. Simulations of the transport of Giardia and manure particles using a simple and flexible power law model for the solid‐water mass exchange term provided a satisfactory description of the effluent and spatial distribution data. The cumulative size distribution (CSD) of manure particles in the suspension initially and after passage through the packed columns was used to identify the mechanisms that were controlling the deposition of manure particles and Giardia The CSD data indicated that manure particles were completely removed at early times by mechanical filtration and/or straining when the ratio of the particle to the median grain diameter was greater than 0.003 to 0.017. However, the CSD changed with increasing time due to deposition‐induced filling of straining sites. The Giardia transport was controlled by straining. For a given sand, higher effluent concentrations of Giardia were observed in the presence than in the absence of manure suspension. The relative increase of Giardia in the effluent concentrations varied from 75 to 172%. Hence, pathogen transport studies conducted in the absence of manure suspension may underestimate transport potential in manure‐contaminated environments.
Methane Production during Storage of Anaerobically Digested Municipal Organic Waste
Authors: Hansen Trine Lund , Sommer Svend G. , Gabriel S⊘ren , Christensen Thomas H. 
Published: April 2006

ABSTRACTAnaerobic digestion of source‐separated municipal organic waste is considered feasible in Denmark. The limited hydraulic retention in the biogas reactor (typically 15 d) does not allow full degradation of the organic waste. Storage of anaerobically digested municipal organic waste can therefore be a source of methane (CH4) emission that may contribute significantly to the potential global warming impact from the waste treatment system. This study provides a model for quantifying the CH4 production from stored co‐digested municipal organic waste and estimates the production under typical Danish climatic conditions, thus quantifying the potential global warming impact from storage of the digested municipal organic waste before its use on agricultural land. Laboratory batch tests on CH4 production as well as temperature measurements in eight full‐scale storage tanks provided data for developing a model estimating the CH4 production in storage tanks containing digested municipal organic waste. The temperatures measured in separate storage tanks on farms receiving digested slurry were linearly correlated with air temperature. In storage tanks receiving slurry directly from biogas reactors, significantly higher temperatures were measured due to the high temperatures of the effluent from the reactor. Storage tanks on Danish farms are typically emptied in April and have a constant inflow of digested material. During the warmest months the content of digested material is therefore low, which limits the yearly CH4 production from storage.
Poultry Litter Application to Loblolly Pine Forests
Authors: Friend Alexander L. , Roberts Scott D. , Schoenholtz Stephen H. , Mobley Juanita A. , Gerard Patrick D. 
Published: April 2006

ABSTRACTForestland application of poultry manure offers an alternative to the conventional practice of pastureland application. Before such a practice is considered viable, however, it must be demonstrated that the forest ecosystem is capable of absorbing the nutrients contained in poultry manure, especially nitrogen (N) and phosphorus (P). From the forestry perspective, it must also be demonstrated that tree growth is not diminished. We investigated these questions using loblolly pine (Pinus taeda L.) stands growing in central Mississippi in an area of high poultry production. Stockpiled broiler litter was applied to newly thinned, 8‐yr‐old stands at 0, 4.6, and 18.6 dry Mg ha−1, supplying 0, 200, and 800 kg N ha−1 and 0, 92, and 370 kg P ha−1, respectively. Levels of nitrate in soil water, monitored at a 50‐cm depth with porous cup tension lysimeters, exceeded 10 mg N L−1 during the first two years after application in the 18.6 Mg ha−1 rate but only on two occasions in the first year for the lower rate of application. Phosphate was largely absent from lysimeter water in all treatments. Other macronutrients (K, Ca, Mg, S) were elevated in lysimeter water in proportion to litter application rates. Soil extractable nitrate showed similar trends to lysimeter water, with substantial elevation during the first year following application for the 18.6 Mg ha−1 rate. Mehlich III–extractable phosphate peaked in excess of 100 μg P g−1 soil during the third year of the study for the 18.6 Mg ha−1 rate. The 4.6 Mg ha−1 rate did not affect extractable soil P. Tree growth was increased by the poultry litter. Total stem cross‐sectional area, or basal area, was approximately 20% greater after 2 yr for both rates of litter application. Overall, the nutrients supplied by the 4.6 Mg ha−1 rate were contained by the pine forest and resulted in favorable increases in tree growth. The higher rate, by contrast, did pose some risk to water quality through the mobilization of nitrate. These results show that, under the conditions of this study, application of poultry litter at moderate rates of approximately 5 Mg ha−1 to young stands of loblolly pine offers an alternative disposal option with minimal impacts to water quality and potential increases in tree growth.
Comparing Carbon Substrates for Denitrification of Subsurface Drainage Water
Authors: Greenan Colin M. , Moorman Thomas B. , Kaspar Thomas C. , Parkin Timothy B. , Jaynes Dan B. 
Published: April 2006

ABSTRACTNitrate in water from tile drained corn (Zea maysL.) and soybean [Glycine max(L.) Merr.] fields in the U.S. Midwest contributes to nitrate contamination of surface waters. Denitrification‐based biofilters are a promising strategy for reducing nitrate concentrations, but these systems require an external carbon supply to sustain denitrification. The ability of four organic materials to serve as carbon substrates for denitrification biofilters was evaluated in this laboratory study. Wood chips, wood chips amended with soybean oil, cornstalks, and cardboard fibers were mixed with subsoil (oxidized till) and incubated anaerobically for 180 d. Periodically,15NO3–N was added to maintain nitrate N concentrations between 10 and 100 mg L−1All of the materials stimulated NO3–N removal and the degree of removal from highest to lowest was: cornstalks, cardboard fibers, wood chips with oil, and wood chips alone. Analysis of15N showed that immobilization and dissimilatory nitrate reduction to ammonium accounted for <4% of NO3–N removal in all treatments, therefore denitrification was the dominant NO3–N removal process. Cardboard fibers, wood chips and oil, and wood chips alone did not support as much denitrification as cornstalks, but their rates of NO3–N removal were steady and would probably continue longer than cornstalks. The addition of soybean oil to wood chips significantly increased denitrification over wood chips alone.
Mineralization of Hormones in Breeder and Broiler Litters at Different Water Potentials and Temperatures
Authors: Hemmings Sarah N. J. , Hartel Peter G. 
Published: April 2006

ABSTRACTWhen poultry litter is landspread, steroidal hormones present in the litter may reach surface waters, where they may have undesirable biological effects. In a laboratory study, we determined the mineralization of [4–14C]‐labeled 17β‐estradiol, estrone, and testosterone in breeder litter at three different water potentials (−56, −24, and −12 MPa) and temperatures (25, 35, and 45°C), and in broiler litter at two different water potentials (−24 and −12 MPa) and temperatures (25 and 35°C). Mineralization was similar in both litters and generally increased with increasing water content and decreasing temperature. After 23 wk at −24 MPa, an average of 27, 11, and <2% of the radiolabeled testosterone applied to breeder litter was mineralized to 14CO2 at 25, 35, and 45°C, respectively. In contrast, mineralization of the radiolabeled estradiol and estrone was <2% after 25 wk at all water potentials, except after 17 wk at 25°C and −12 MPa, where up to 5.9% of the estradiol and 7.8% of the estrone was mineralized. The minimal mineralization suggests that the litters may still be potential sources of hormones to surface and subsurface waters.
Impact of Diet, Moisture, Location, and Storage on Soluble Phosphorus in Broiler Breeder Manure
Authors: Maguire R. O. , Plumstead P. W. , Brake J. 
Published: April 2006

ABSTRACTDecreasing dietary phosphorus (P) has the potential to reduce P excreted in manure and therefore alleviate the environmental degradations associated with intensive animal farming. We evaluated reducing dietary P for broiler breeders as an aid to reduce manure total and water soluble phosphorus (WSP). Broiler breeders were fed diets high and low in dietary P, with and without phytase, from 22 to 64 wk of age. At the end of the 42‐wk production period, manure was collected from four locations in each two‐thirds slat, one‐third litter breeder pen: the litter scratch area, under the drinker in the slat area, under the feeder in the slat area, and in a clean area of the slat area away from feeder or drinker. After the initial sampling, all manure was removed from pens and representative samples were stored for 6 mo with and without feed mixed in to simulate the effect of spilled feed. Total P was determined on all pen samples, and moisture and WSP determined on the pen and stored samples. The manure collected under the drinker had much greater moisture due to spilled water. This was associated with much greater WSP in this location, showing the importance of good water management. The manure from under the feeder had similar WSP as manure from the clean area, so spilled feed did not significantly affect WSP. Dietary phytase either had no effect or significantly decreased manure WSP. However, addition of dietary phytase to the feed led to slightly elevated manure moisture. Since moisture was correlated with manure WSP this may explain some of the variability in WSP results between studies. Over 6 mo of storage WSP increased and generally followed the same ranking order at 168 d as at 1 d among the dietary treatments (high > high + phytase > low > low + phytase). Combining decreased dietary P and phytase reduced both manure total P and WSP by 42%. As total P and WSP are indicators of the long and short term impacts manure applications can have on P losses from manured soils, diet modification should be seen as environmentally beneficial.
Arteries, Elastic Properties of
Authors: Hayashi Kozaburo 
Published: April 2006

Abstract

The elastic properties of arterial wall are very important because they are closely related to arterial physiology and pathology, especially via effects on blood flow and arterial mass transport. Furthermore, stresses and strains in the arterial wall, which are prerequisite for the understanding of the pathophysiology and mechanics of the cardiovascular system, cannot be analyzed without exact knowledge of the arterial elasticity. First of all, the structure of arterial wall and its basic elastic characteristics are briefly explained. Then, tensile testing,
in vitro
pressure‐diameter tests, and in vivo techniques are dealt with for the measurement of arterial elasticity. Several equations and parameters proposed to mathematically describe biomechanical data obtained from uniaxial tensile and pressure‐diameter tests are introduced together with representative constitutive equations for the complete expression of arterial elasticity. Finally, the article demonstrates several results on the elastic properties of normal and diseased arterial walls, in particular in hypertension and atherosclerosis.
Audiometry
Authors: Borton Thomas E. , Borton Bettie B. , Blumsack Judith T. 
Published: April 2006

Abstract
Audiometry is the measurement of hearing. It entails the use of electronic instrumentation to deliver auditory signals to a listener and is used in the functional assessment, diagnosis, and rehabilitation of hearing impairment. Modern assessment of the auditory system includes measurement of sensitivity to pure tones and speech, evaluation of middle ear function (e.g., with tympanometry and acoustic reflex measurement), auditory evoked potential evaluation, and measurement of otoacoustic emissions. The sound pathways of the ear and psychophysical methods used in audiometry are reviewed in this chapter. Fundamentals and interpretation of pure tone and speech audiometric results are highlighted, and the clinical applications of modern electrophysiologic methods for audiometry are described. Auditory evoked potential, acoustic immittance, and otoacoustic emission measures are discussed.
Biofeedback
Authors: Arena John C. , Devineni Trishul , McGowan Edward J. 
Published: April 2006

AbstractThe theory and practice of biofeedback has rapidly matured over the last three decades due in part to advances in the fields of microelectronics, digital computing, and signal processing. There has been concurrent progress in our understanding of complex biological systems, human disease mechanisms, and behavioral principles of learning involved in physiological functions. The medical and scientific instrumentation of biofeedback has proliferated along with the expansion of clinical applications of the technology to numerous disease states. In this article, an attempt is made to clearly define the diffuse area of biofeedback and provide a brief historical overview of its development. A review of the basic learning principles derived from laboratory findings underlying biofeedback and competing theories is made. Described are the major types of medical instrumentation and engineering design specifications of common biofeedback systems. Also covered are the basic physiological parameters captured and processed by these flexible medical devices. The literature documenting the outcomes of widely used biofeedback paradigms in clinical settings are briefly highlight. Finally, some major themes and future directions that the technology and medical application of biofeedback are likely to take us are proposed.
Bioinformatics
Authors: Abbas Ali , Liu Lei 
Published: April 2006

AbstractThe past two decades have witnessed revolutionary changes in biomedical research and biotechnology and an explosive growth of biomedical data. High throughput technologies developed in automated DNA sequencing, functional genomics, proteomics, and metabolomics enable production of such high volume and complex data that the data analysis becomes a big challenge. Consequently, a promising new field, bioinformatics has emerged and is growing rapidly. Combining biological studies with computer science, mathematics, and statistics, bioinformatics develops methods, solutions, and software to discover patterns, generate models, and gain insight knowledge of complex biological systems.
Biomagnetism
Authors: Cheyne Douglas , Verba Jini 
Published: April 2006

AbstractThe science of biomagnetism refers to the measurement of magnetic fields produced by living organisms. These tiny magnetic fields are produced by naturally occurring electric currents resulting from muscle contraction, or signal transmission in the nervous system, or by the magnetization of biological tissue. This article discusses biomagnetic instruments and applications of these instruments as well as future direction of the field.
Biomaterials for Dentistry
Authors: Armstrong Steve 
Published: April 2006

Abstract
Biomaterials are used in the oral cavity either to restore function, comfort, or aesthetics caused by developmental disorders, disease, or trauma. More elective procedures are being requested and performed purely for aesthetic purposes as the incidence of caries has dropped in certain population groups and as patients have become more aware of various restorative or cosmetic options. However, the replacement of diseased tooth structure or missing teeth accounts for the bulk of work in restorative dentistry. The instruments and materials used in the surgical aspects of oral, maxillofacial and periodontal surgery have much in common with medicine. This article will focus on those commonly used materials in the restoration of individual teeth or the replacement of missing teeth.
Biomaterials, Absorbable
Authors: Borden Mark 
Published: April 2006

AbstractCurrent techniques in orthopedic surgery use a variety of implants that are specifically designed to aid in the healing of bone, ligaments, and tendons throughout the skeleton. These implants are commonly used to provide temporary mechanical support and stabilization to the site of the injury while the tissue heals. However, once their function is complete, the implants remain and can be a source of long‐term complications. Resorbable implants, on the other hand, are a unique class of devices that have the ability to breakdown into harmless by‐products that are absorbed by the body. Composed of polymers, ceramics, or composites, these versatile materials have different mechanisms of resorption, degradation profiles, and mechanical properties. As a result, they have been used in a variety of clinical applications including fracture repair, sports medicine, and bone grafting. This chapter discusses the requirements and function of resorbable orthopedic devices, and reviews the properties and healing behavior of common resorbable materials.
Biomaterials: Bioceramics
Authors: Jones Julian R. , Hench Larry L. 
Published: April 2006

Abstract

Bioceramics are ceramics that can be used for the reconstruction or regeneration of diseased or damaged tissues, they can be bioinert (e.g., alumina and zirconia), resorbable in the body (e.g., tricalcium phosphate), or bioactive (e.g., bioactive glass, hydroxyapatite), which bond to certain tissues and are used in regenerative medicine. In orthopedics, diseased joints are traditionally replaced by prostheses made of bioinert materials that may last up to 15 years. Advanced metal alloys, special polymers, and bioinert ceramics are the basis of this success. However, as life expectancy of our population increases, patients require >30 years from their devices. For large bone defects and severely diseased or damaged soft tissue such as the lung and the liver, transplantation is used, but donors are never enough. To satisfy this growing need for very long term tissue repair a shift of emphasis on
replacement
of tissues to
regeneration
of tissues is needed. An understanding and use of biological approaches is essential. This article describes current applications of bioceramics as medical devices and discusses development of porous bioceramic and composite scaffolds for tissue engineering. It suggests that bioactive ceramics will be used for future biomedical devices for regenerative medicine due to their potential for guiding tissue regeneration by stimulating cells at the genetic level.
Biomaterials, Corrosion and Wear of
Authors: Narayan Roger J. , Marek Miroslav , Jin Chunming 
Published: April 2006

Abstract
Many materials suffer degradation with time when exposed to aggressive chemical environments within the human body. In metallic biomaterials, degradation results from electrochemical corrosion. Ceramic and polymeric biomaterials may undergo physical or chemical deterioration processes. In addition, mechanical forces may act to increase damage by wear, abrasion, or environment‐induced cracking processes.
Biomaterials, Polymers
Authors: Zhang Min , James Susan P. 
Published: April 2006

Abstract
Biomaterials are materials of synthetic as well as of natural origin in contact with tissue or biological fluids, including metals, ceramics, polymers, and composites. The main advantages of polymeric biomaterials over ceramics and metals are the variety of composition, properties and available forms (solid, hydrogel, and solution), and ease of fabrication into complex shapes (films, sheets, fibers, powders, etc.) and structures because synthetic polymers are easily tailored to specific applications. As a result, the types of polymerization, the composition and properties of polymers, and polymers used as biomaterials will be discussed.
Biomaterials, Surface Properties of
Authors: McArthur Sally L. , Shard Alexander G. 
Published: April 2006

Abstract
In this article, we intend to provide a broad overview of the basic properties of surfaces, their interactions with biological systems, and how surfaces can be changed to suit particular biomaterial applications. Of particular importance is the requirement for surface characterization. Differences between surface and bulk properties can arise via a number of different processes. However they arise, it is important to ensure that the surface properties of the material are verified before ascribing any biological effect to the material. To complete this article, we provide an outline of the most commonly employed surface characterization techniques and include references to more detailed texts to aid the interested reader.