Assessing the cumulative impacts of geographically isolated wetlands on watershed hydrology using the SWAT model coupled with improved wetland modules.

Despite recognizing the importance of wetlands in the Coastal Plain of the Chesapeake Bay Watershed (CBW) in terms of ecosystem services, our understanding of wetland functions has mostly been limited to individual wetlands and overall catchment-scale wetland functions have rarely been investigated. This study is aimed at assessing the cumulative impacts of wetlands on watershed hydrology for an agricultural watershed within the Coastal Plain of the CBW using the Soil and Water Assessment Tool (SWAT). We employed two improved wetland modules for enhanced representation of physical processes and spatial distribution of riparian wetlands (RWs) and geographically isolated wetlands (GIWs). This study focused on GIWs as their hydrological impacts on watershed hydrology are poorly understood and GIWs are poorly protected. Multiple wetland scenarios were prepared by removing all or portions of the baseline GIW condition indicated by the U.S. Fish and Wildlife Service National Wetlands Inventory geospatial dataset. We further compared the impacts of GIWs and RWs on downstream flow (i.e., streamflow at the watershed outlet). Our simulation results showed that GIWs strongly influenced downstream flow by altering water transport mechanisms in upstream areas. Loss of all GIWs reduced both water routed to GIWs and water infiltrated into the soil through the bottom of GIWs, leading to an increase in surface runoff of 9% and a decrease in groundwater flow of 7% in upstream areas. These changes resulted in increased variability of downstream flow in response to extreme flow conditions. GIW loss also induced an increase in month to month variability of downstream flow and a decrease in the baseflow contribution to streamflow. Loss of all GIWs was shown to cause a greater fluctuation of downstream flow than loss of all RWs for this study site, due to a greater total water storage capacity of GIWs. Our findings indicate that GIWs play a significant role in controlling hydrological processes in upstream areas and downstream flow and, therefore, protecting GIWs is important for enhanced hydrological resilience to extreme flow conditions in this region.

Accuracy and precision of direct bone conduction measurements.

OBJECTIVES: Variability in Baha® sound processor fittings arise from several sources including the nature of the implant-to-bone transmission and transcranial attenuation in patients with single-sided sensorineural deafness. One method of improving the predictability of Baha fittings is to measure the individual patient's actual bone conduction thresholds via the implant, thereby removing the influence of skin thickness and/or implant location site. METHODOLOGY: One hundred thirty eight adult wearers of the Baha System participated in the study. Direct bone conduction thresholds were obtained through the BC Direct feature of the Cochlear™ Baha Fitting Software combined with the CochlearBaha BP100 sound processor. Test-retest reliability measurement was performed in 58 participants. RESULTS: Improved transmission of sound through the implant rather than transcutaneously through the skin was confirmed. On average, the BC Direct thresholds were closer to the patient's unmasked thresholds than the masked values. In patients with single-sided sensorineural deafness, BC Direct results were elevated compared to the contralateral bone conduction thresholds due to transcranial attenuation. The test-retest reliability for the BC Direct measurements was within ±5 dB, which is in within the accepted variability for audiometric test measurements. CONCLUSIONS: Direct bone conduction measurement provides a validated method of comparing the transcutaneous thresholds as measured through audiometry with the percutaneous responses from the Baha sound processor. The Baha fitting based on direct measurements of bone conduction may require less fine-tuning and provide a greater understanding of the variability of the bone conduction sound pathway.

Intravenous pamidronate for refractory lymphedema.

BACKGROUND: Based on beneficial reports of pamidronate use for reflex sympathetic dystrophy in reduction of pain and swelling, this drug can be studied as a novel treatment for refractory lymphedema. This study aims to determine the effectiveness of pamidronate on lymphedema and its possible side effects. METHODS: Twelve cases of lower limb refractory lymphedema were enrolled. They received intravenous pamidronate monthly for 3 consecutive months and were followed by measuring any discomfort with visual analog scale (VAS) and physician global assessment, based on objective signs of limb volume and circumference. RESULTS: The limb volume, circumference, and satisfaction of the patients improved significantly. CONCLUSION: Pamidronate when is added to conservative treatments may reduce lymphedema and improve the patient's comfort.

Ex vivo evaluation of insulin nanoparticles using chitosan and arabic gum.

Polymeric delivery systems based on nanoparticles have emerged as a promising approach for peroral insulin delivery. The aim of the present study was to investigate the release of insulin nanoparticulate systems and ex vivo studies. The nanoparticles were prepared by the ion gelation method. Particle size distribution, zeta potential, and polydispersity index of the nanoparticles were determined. It was found that the nanoparticles carried positive charges and showed a size distribution in the range of 170-200 nm. The electrostatic interactions between the positively charged group of chitosan and negatively charged groups of Arabic gum play an important role in the association efficiency of insulin in nanoparticles. In vitro insulin release studies showed an initial burst followed by a slow release of insulin. The mucoadhesion of the nanosystem was evaluated using excised rat jejunum. Ex vivo studies have shown a significant increase in absorption of insulin in the presence of chitosan nanoparticles in comparison with free insulin.

Uncertainty evaluation of coliform bacteria removal from vegetated filter strip under overland flow condition.

Vegetated filter strips (VFS) have become an important component of water quality improvement by reducing sediment and nutrients transport to surface water. This management practice is also beneficial for controlling manure-borne pathogen transport to surface water. The objective of this work was to assess the VFS efficiency and evaluate the uncertainty in predicting the microbial pollutant removal from overland flow in VFS. We used the kinematic wave overland flow model as implemented in KINEROS2 coupled with the convective-dispersive overland transport model which accounts for the reversible attachment-detachment and surface straining of infiltrating bacteria. The model was successfully calibrated with experimental data obtained from a series of simulated rainfall experiments at vegetated and bare sandy loam and clay loam plots, where fecal coliforms were released from manure slurry applied on the top of the plots. The calibrated model was then used to assess the sensitivity of the VFS efficiency to the model parameters, rainfall duration, and intensity for a case study with a 6-m VFS placed at the edge of 200-m long field. The Monte Carlo simulations were also performed to evaluate the uncertainty associated with the VFS efficiency given the uncertainty in the model parameters and key inputs. The VFS efficiency was found to be <95% in 25%, <75% in 23%, and <25% in 20% of cases. Relatively long high-intensity rainfalls, low hydraulic conductivities, low net capillary drives of soil, and high soil moisture contents before rainfalls caused the partial failure of VFS to retain coliforms from the infiltration excess runoff.

Storm water pollutant removal performance of compost filter socks.

In 2005, the U.S. Environmental Protection Agency (USEPA) National Menu of Best Management Practices (BMPs) listed compost filter socks (FS) as an approved BMP for controlling sediment in storm runoff on construction sites. The objectives of this study were to determine if FS with or without the addition of a flocculation agent to the FS system can significantly remove (i) suspended clay and silt particulates, (ii) ammonium nitrogen (NH(4)-N) and nitrate-nitrite nitrogen (NO(3)-N), (iii) fecal bacteria, (iv) heavy metals, and (v) petroleum hydrocarbons from storm water runoff. Five separate (I-V) 30-min simulated rainfall-runoff events were applied to soil chambers packed with Hartboro silt loam (fine-loamy, mixed, active, nonacid, mesic fluvaquentic Endoaquepts) or a 6-mm concrete veneer on a 10% slope, and all runoff was collected and analyzed for hydraulic flow rate, volume, pollutant concentrations, pollutant loads, and removal efficiencies. In corresponding experiments, runoff was analyzed for (i) size of sediment particles, (ii) NH(4)-N and NO(3)-N, (iii) total coliforms (TC) and Escherichia coli, (iv) Cd, Cr, Cu, Ni, Pb and Zn, and (v) gasoline, diesel, and motor oil, respectively. Results showed that: (i) FS removed 65% and 66% of clay (<0.002 mm) and silt (0.002-0.05 mm), respectively; (ii) FS removed 17%, and 11% of NH(4)-N and NO(3)-N, respectively and when NitroLoxx was added to the FS, removal of NH(4)-N load increased to 27%; (iii) total coliform and E. coli removal efficiencies were 74 and 75%, respectively, however, when BactoLoxx was added, removal efficiency increased to 87 and 99% for TC and 89 and 99% for E. coli, respectively; (iv) FS removal efficiency for Cd, Cr, Cu, Ni, Pb, and Zn ranged from 37 to 72%, and, when MetalLoxx was added, removal efficiency ranged from 47 to 74%; and (v) FS removal efficiency for the three petroleum hydrocarbons ranged from 43 to 99% and the addition of PetroLoxx increased motor oil and gasoline removal efficiency in the FS system.

Development of a Gas Empowered Drug Delivery system for peptide delivery in the small intestine.

The aim of this investigation was to design a novel Gas Empowered Drug Delivery (GEDD) system for CO(2) forced transport of peptide drugs together with mucoadhesive polymers to the surface of the small intestine. The GEDD effect of the core tablet was achieved using CO(2) gas to push insulin together with the mucoadhesive excipients poly(ethyleneoxide) (PEO) and the permeation enhancer trimethyl chitosan (TMC) to the surface of the small intestine. The in-vitro insulin release showed that almost 100% of the insulin was released from enterically coated tablets within 30 min at pH 6.8. The designed GEDD system was shown to increase the insulin transport by approximately 7 times in comparison with the free insulin across sheep's intestine ex-vivo. Three different peroral formulations were administered to male rabbits: F1 containing no TMC or PEO, F2 containing PEO but no TMC and F3 containing both PEO and TMC. The administrations of insulin using the formulation F1 resulted in a low FR value of 0.2%+/-0.1%, while the formulations F2 and F3 resulted in a much higher FR values of 0.6+/-0.2% and 1.1%+/-0.4%, respectively. Hence, the insulin permeation achieved by the GEDD system is primarily due to the enhancing effect of TMC and the mucoadhesive properties of PEO both of which synergistically increase the bioavailability of insulin.

Permeation enhancer effect of chitosan and chitosan derivatives: comparison of formulations as soluble polymers and nanoparticulate systems on insulin absorption in Caco-2 cells.

In this study four quaternized derivatives of chitosan: trimethyl chitosan (TMC), dimethylethyl chitosan (DMEC), diethylmethyl chitosan (DEMC) and triethyl chitosan (TEC) with degree of substitution of approximately 50+/-5% were synthesized and their effect on the permeability of insulin across intestinal Caco-2 monolayers was studied and compared with chitosan both in free-soluble form and in nanoparticulate systems. Transepithelial electrical resistance (TEER) studies revealed that all four chitosan derivatives in free-soluble forms were able to decrease the TEER value in the following order TMC>DMEC>DEMC=TEC>chitosan, indicating their abilities to open the tight junctions. Recovery studies on the TEER showed that the effect of the polymers on Caco-2 cell monolayer is reversible and proves the viability of cells after incubation with all polymers. A similar rank order was also observed when measuring the zeta-potentials of the various polymers in solution form. Transport studies of insulin together with the soluble polymers across Caco-2 cell layers showed the following ranking: TMC>DMEC>DEMC>TEC>chitosan which is in agreement with the strength of the cationic charge of the polymer. In comparison to the free-soluble polymers, the nanoparticles prepared by ionic gelation of the chitosan and its quaternized derivatives had much lower effect on decreasing the TEER by opening of the tight junctions. This can be explained by the reduced available amount of positive charge at the surface of the nanoparticles. In accordance with these results, the insulin loaded nanoparticles showed much less permeation across the Caco-2 cell monolayer in comparison to the free-soluble polymers. Mass balance transport studies revealed that a substantial amount of the nanoparticles has been entrapped into the Caco-2 monolayer or attached to the cell surface. It can thus be stated that while free-soluble polymers can reversibly open the tight junctions and increase the permeation of insulin, the nanoparticles had basically only a low effect on the opening of the tight junction and the paracellular transport of insulin across the Caco-2 cell monolayer. These data convincingly show that nanoparticles consisting of chitosan and its quaternary ammonium derivatives loaded with insulin are less effective in facilitating paracellular transport across Caco-2 cell monolayers than the corresponding free polymers.

Preparation, characterization and antibacterial activities of chitosan, N-trimethyl chitosan (TMC) and N-diethylmethyl chitosan (DEMC) nanoparticles loaded with insulin using both the ionotropic gelation and polyelectrolyte complexation methods.

TMC and DEMC, quaternized derivatives of chitosan, have been shown to have penetration enhancement properties and able to open the tight junctions of the intestinal epithelia at neutral and alkaline pH environments. The use of the nanoparticulate systems has the advantage of protecting the peptidic drugs from the harsh environment of the gastrointestinal tract. Hence, the aim of this study was to synthesize and characterize TMC and DEMC, both with quaternization degrees of 50+/-5%, which were then used to prepare insulin nanoparticles with two different methods: ionotropic gelation and the polyelectrolyte complexation (PEC) techniques. The obtained nanoparticles were then characterized for size, zeta potential, insulin loading and release as well as antibacterial activities. The results showed that nanoparticles prepared by the PEC method had higher insulin loading efficiency and zeta potential than those made by the ionotropic gelation method and may subsequently be used for further in vitro, ex vivo and in vivo studies. Moreover, the antibacterial studies suggest that the polymers in free form have higher antibacterial activity against Gram-positive bacteria than in the nanoparticulate form.

Comparison of release and transport of manure-borne Escherichia coli and enterococci under grass buffer conditions.

AIM: To test the hypothesis that Escherichia coli and enterococci bacteria have similar release rates and transport characteristics after being released from land-applied manure. METHODS AND RESULTS: Turfgrass soil sod was placed into 200 cm long boxes that had the top two 25 cm sections separated to monitor the release and infiltration of bacteria, which affected bacteria transport in the rest of the box. Dairy manure with added KBr was broadcast on the top two sections. Boxes with either live or dead grass stand were placed under a rainfall simulator for 90 min. Runoff and infiltration samples were collected and analysed for Br, E. coli, enterococci and turbidity. Significant differences in release kinetics of E. coli and enterococci were found. A change from first-order release kinetics to zero-order kinetics after 1 h of rainfall simulation was observed. CONCLUSION: Differences in release rates but not in the subsequent transport were observed for E. coli and enterococci. SIGNIFICANCE AND IMPACT OF THE STUDY: Because both E. coli and enterococci are currently used as indicator organisms for manure-borne pathogens, the differences in their release rates may affect the efficiency of using these organisms as indicators.

Modeling manure-borne bromide and fecal coliform transport with runoff and infiltration at a hillslope.

Hillslope vegetated buffers are recommended to prevent water pollution from agricultural runoff. However, models to predict the efficacy of different grass buffer designs are lacking. The objective of this work was to develop and test a mechanistic model of coupled surface and subsurface flow and transport of bacteria and a conservative tracer on hillslopes. The testing should indicate what level of complexity and observation density might be needed to capture essential processes in the model. We combined the three-dimensional FEMWATER model of saturated-unsaturated subsurface flow with the Saint-Venant model for runoff. The model was tested with data on rainfall-induced fecal coliforms (FC) and bromide (Br) transport from manure applied at vegetated and bare 6-m long plots. The calibration of water retention parameters was unnecessary, and the same manure release parameters could be used both for simulations of Br and FC. Surface straining rates were similar for Br and bacteria. Simulations of Br and FC concentrations were least successful for the funnels closest to the source. This could be related to the finger-like flow of the manure from the strip along the bare slopes, to the transport of Br and FC with manure colloids that became strained at the grass slope, and to the presence of micro-ponds at the grassed slope. The two-dimensional model abstraction of the actual 3D transport worked well for flux-averaged concentrations. The model developed in this work is suitable to simulate surface and subsurface transport of agricultural contaminants on hillslopes and to evaluate efficiency of grass strip buffers, especially when lateral subsurface flow is important.

Rainfall-induced release of fecal coliforms and other manure constituents: comparison and modeling.

Modeling release of fecal coliforms is an important component of fate and transport simulations related to environmental water quality. Manure constituents other than fecal coliforms may serve as natural tracers of fecal contamination provided that their release from manure to runoff is similar to the fecal coliform release. The objectives of this work were to compare release of fecal coliforms (FC), chloride (Cl-), organic carbon (OC), and water-soluble phosphorus (P) from dissolving manure and to assess the performance of three models in describing the observed release. Bovine manure was applied on 0.5- by 0.3-m bare and vegetated subplots with 20% slope on sandy loam and clay loam soils. Concentrations of Cl-, FC, OC, and P were measured in runoff collected from troughs at the edges of the subplots at 5-min intervals during 1-h rainfall simulations. The one-parametric exponential model and two-parametric Vadas-Kleinman-Sharpley model and Bradford-Schijven model were fitted to the data. The Bradford-Schijven model had uncorrelated parameters, one of which was linearly related to the irrigation rate, and another parameter reflected the presence or the absence of vegetation. Kinetics of the FC release from manure was similar to the release kinetics of P and OC. The Bradford-Schijven model is recommended to simulate the release of manure constituents.

Fate of dietary perchlorate in lactating dairy cows: Relevance to animal health and levels in the milk supply.

Perchlorate is a goitrogenic anion that competitively inhibits the sodium iodide transporter and has been detected in forages and in commercial milk throughout the U.S. The fate of perchlorate and its effect on animal health were studied in lactating cows, ruminally infused with perchlorate for 5 weeks. Milk perchlorate levels were highly correlated with perchlorate intake, but milk iodine was unaffected, and there were no demonstrable health effects. We provide evidence that up to 80% of dietary perchlorate was metabolized, most likely in the rumen, which would provide cattle with a degree of refractoriness to perchlorate. Data presented are important for assessing the environmental impact on perchlorate concentrations in milk and potential for relevance to human health.

Runoff transport of faecal coliforms and phosphorus released from manure in grass buffer conditions.

AIMS: To test the hypothesis that faecal coliform (FC) and phosphorus (P) are transported similarly in surface runoff through the vegetative filter strip after being released from land-applied manure. METHODS AND RESULTS: The Hagerstown soil was packed into boxes that were 10 cm deep, 30 cm wide and 100, 200 or 300 cm long. Grass was grown in boxes prior experiments. Same-length boxes were placed under rainfall simulator and tilted to have with either 2% or 4% slopes. Dairy manure was broadcast on the upper 30-cm section. Rainfall was simulated and runoff samples were collected and analysed for Cl, FC and total phosphorus (TP). Mass recovery, the concentration decrease rate k, and the ratio FC : TP showed that there was a consistent relationship between FC and TP in runoff. CONCLUSION: The FC and TP transport through simulated vegetated buffer strips were highly correlated. SIGNIFICANCE AND IMPACT OF THE STUDY: As a knowledge base on the effect of the environmental parameters on P transport in vegetated buffer strips is substantially larger than for manure-borne bacteria, the observed similarity may enhance ability to assess the efficiency of the vegetated buffer strips in retention of FC currently used as indicator organisms for manure-borne pathogens.

Runoff loss of pesticides and soil: a comparison between vegetative mulch and plastic mulch in vegetable production systems.

Current vegetable production systems use polyethylene (plastic) mulch and require multiple applications of agrochemicals. During rain events, runoff from vegetable production is enhanced because 50 to 75% of the field is covered with an impervious surface. This study was conducted to quantify off-site movement of soil and pesticides with runoff from tomato (Lycopersicon esculentum Mill.) plots containing polyethylene mulch and a vegetative mulch, hairy vetch (Vicia villosa Roth). Side-by-side field plots were instrumented with automated flow meters and samplers to measure and collect runoff, which was filtered, extracted, and analyzed to determine soil and pesticide loss. Seasonal losses of two to four times more water and at least three times as much sediment were observed from plots with polyethvlene mulch (55.4 to 146 L m(-2) and 247 to 535 g m(-2), respectively) versus plots with hairy vetch residue (13.7 to 75.7 L m(-2) and 32.8 to 118 g m(-2), respectively). Geometric means (+/-standard deviation) of total pesticide loads for chlorothalonil (tetrachloroisophthalonitrile) and alpha-and beta-endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro6,9-methano-2,4,3-benzodioxathiepin 3-oxide) for a runoff event were 19, 6, and 9 times greater from polyethylene (800+/-4.6, 17.6+/-3.9, and 39.1+/-4.9 microg m(-2), respectively) than from hairy vetch mulch plots (42+/-6.0, 2.8+/-5.0, and 4.3+/-4.6 microg m(-2), respectively) due to greater concentrations and larger runoff volumes. The increased runoff volume, soil loss, and off-site loading of pesticides measured in runoff from the polyethylene mulch suggests that this management practice is less sustainable and may have a harmful effect on the environment.

Impact of hairy vetch cover crop on herbicide transport under field and laboratory conditions.

This study was conducted to evaluate the effect of hairy vetch cover crop residue on runoff losses of atrazine and metolachlor under both no-till corn field plots and from a laboratory runoff system. A 2-year field study was conducted in which losses of atrazine and metolachlor from vetch and non-vetch field plots were determined from the first runoff event after application (5 and 25 days after application in 1997 and 1998, respectively). A laboratory study was conducted using soil chambers, designed to simulate field soil, water, vegetation, and herbicide treatment conditions, subjected to simulated rain events of 5, 6, 20 and 21 days after application, similar to the rainfall pattern observed in the field study. Atrazine losses ranged from 1.2 to 7.2% and 0.01 to 0.08% and metolachlor losses ranged from 0.7 to 3.1% and 0.01 to 0.1% of the amount applied for the 1997 and 1998 runoff events, respectively. In the laboratory study, atrazine runoff losses ranged from 6.7 to 22.7% and 4.2 to 8.5% and metolachlor losses ranged from 3.6 to 9.8% and 1.1 to 4.7% of the amount applied for the 5-6 and 20-21 day events, respectively. The lower losses from the field study were due to smaller rainfall amounts and a series of small rains prior to the runoff event that likely washed herbicides off crop residue and into soil where adsorption could occur. Runoff losses of both herbicides were slightly higher from non-vetch than vetch field plots. Losses from the laboratory study were related to runoff volume rather than vegetation type.

Mycotic aneurysm of the thoracic aorta due to Aspergillus terreus: case report and review.

Mycotic aneurysms of the aorta caused by fungi are uncommon. We describe an unusual case of aortic aneurysm infection caused by Aspergillus terreus, which most likely spread from an adjacent pulmonary focus. Successful treatment included partial pneumonectomy, resection of the aneurysm with graft repair, and prolonged sequential administration of amphotericin B and itraconazole. A review of the published experience with aortic aneurysms caused by Aspergillus species is also presented. When invasive aspergillosis is suspected in proximity to areas with major vascular structures in immunocompromised patients, further investigation to rule out vascular invasion may be warranted. If the diagnosis is confirmed, aggressive and prompt treatment with antifungal agents combined with surgical debridement is essential to improve outcome.

Influence of soil texture and tillage on herbicide transport.

Two long-term no-till corn production studies, representing different soil texture, consistently showed higher leaching of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] to groundwater in a silt loam soil than in a sandy loam soil. A laboratory leaching study was initiated using intact soil cores from the two sites to determine whether the soil texture could account for the observed differences. Six intact soil cores (16 cm dia by 20 cm high) were collected from a four-year old no-till corn plots at each of the two locations (ca. 25 km apart). All cores were mounted in funnels and the saturated hydraulic conductivity (Ksat) was measured. Three cores (from each soil texture) with the lowest Ksat were mixed and repacked. All cores were surface treated with 1.7 kg ai ha(-1) [ring-14C] atrazine, subjected to simulated rainfall at a constant 12 mm h(-1) intensity until nearly 3 pore volume of leachate was collected and analyzed for a total of 14C. On an average, nearly 40% more of atrazine was leached through the intact silt loam than the sandy loam soil cores. For both the intact and repacked cores, the initial atrazine leaching rates were higher in the silt loam than the sandy loam soils, indicating that macropore flow was a more prominent mechanism for atrazine leaching in the silt loam soil. A predominance of macropore flow in the silt loam soil, possibly due to greater aggregate stability, may account for the observed leaching patterns for both field and laboratory studies.

Short-term bridge to transplant using the BVS 5000 in a 22-kg child.

The availability of pulsatile mechanical assist devices for bridge to transplant in pediatric patients is limited owing to the patients' small sizes. Pulsatile devices offer potential advantages over nonpulsatile devices but the risk of hypertensive bleeding must be balanced against that of device thrombosis. We describe our experience using the BVS 5000 external pulsatile device in an 8-year old patient with a body surface area of 0.88 m2.

The incisional pulmonary artery band.

Occasionally early definitive repair of congenital heart disease carries prohibitive mortality, and interval pulmonary artery banding is necessary to protect the pulmonary arterial bed and improve systemic perfusion or prepare a systemic left ventricle for a later arterial switch operation. We describe our technique for effectively banding the pulmonary artery.