Improving stormwater infiltration and retention in compacted urban soils at impervious/pervious surface disconnections with biochar.

Urban development often results in compacted soils, impairing soil structure and reducing the infiltration and retention of stormwater runoff from impervious features. Biochar is a promising organic soil amendment to improve infiltration and retention of stormwater runoff. Soil at the disconnection between impervious and pervious surfaces represents a critical biochar application point for stormwater management from urban impervious features. This study tested the hypothesis that biochar would significantly improve water retention and transmission at four sites, where varying percentages (0%, 2%, and 4% w/w) of biochar were amended to soils between impervious pavement, and pervious grassed slopes. Field-saturated hydraulic conductivity (Ksat) and easily drainable water storage capacity were monitored at these sites for five months (two sites) and 15 months (two sites). At the end of the monitoring periods, the physical, chemical, and biological properties of each site's soil were assessed to understand the impact of biochar on soil aggregation, which is critical for improved soil structure and water infiltration. Results indicated that the field Ksat, drainable water storage capacity, and plant available water content (AWC) were 7.1 ± 3.6 SE, 2.0 ± 0.3 SE, and 2.1 ± 0.3 SE times higher in soils amended with 4% biochar, respectively, compared to the undisturbed soil. Factor analysis elucidated that biochar amendment increased the organic matter content, aggregate mean weight diameter, organo-mineral content, and fungal hyphal length while decreasing the bulk density. Across the 12 biochar/soil combinations, the multiple linear regression models derived from factor analysis described the changes in Ksat and AWC reasonably well with R2 values of 0.51 and 0.71, respectively. Using soil and biochar properties measured before biochar addition, two recent models, developed from laboratory investigations, were found helpful as screening tools to predict biochar's effect on Ksat and AWC at the four field sites. Overall, the findings illustrate that biochar amendment to compacted urban soils can significantly improve soil structure and hydraulic function at impervious/pervious surface disconnections, and screening models help to predict biochar's effectiveness in this context.

The origin and reversible nature of poultry litter biochar hydrophobicity.

Transient changes in wettability complicate the prediction of biochar's hydrologic effects. Biochar wetting properties were characterized from poultry litter biochar (PLBC) produced from slow pyrolysis at temperatures between 300 and 600°C with water drop penetration time (persistence of hydrophobicity) and contact angle (CA; severity of hydrophobicity) measurements. Hydrophobicity was associated with semivolatile organic compounds coating PLBC surfaces, which resulted in 24.4 carbon layers and CAs of 101.1 ± 2.9° at a pyrolysis temperature of 300°C but only 0.4 layers of surface coverage and CAs of 20.6 ± 1.3° when pyrolyzed at 600°C. Mixing PLBC with water removed organic coatings, and storage in water for 72 h decreased CA as much as 81° for the most hydrophobic PLBCs. When mixed with quartz sand of the same particle size, CAs of PLBC-sand mixtures increased from 6.6 ± 1.4° at 0% PLBC mass fraction to 48.3 ± 2.0° at 15% mass fraction. Hydrophobic and hydrophilic PLBCs increased CA by nearly identical amounts at 2 and 5% mass fractions, which was explained by the influence of PLBC particle topology on macroscopic surface roughness of PLBC-sand mixtures. For environmentally relevant situations, PLBC-sand mixtures at mass fractions ≤15% remained water wetting. However, all PLBC additions increased CA, which may alter infiltration rates and induce preferential water flow.

High risk men's perceptions of pre-implantation genetic diagnosis for hereditary breast and ovarian cancer.

BACKGROUND: Pre-implantation genetic diagnosis (PGD) is an assisted reproductive technology procedure which provides parents with the option of conducting genetic analyses to determine if a mutation is present in an embryo. Though studies have discussed perceptions of PGD from a general population, couples or high-risk women, no studies to date have specifically examined PGD usage among men. This study sought to explore perceptions and attitudes towards PGD among males who either carry a BRCA mutation or have a partner or first degree relative with a BRCA mutation. METHODS: A cross-sectional survey was conducted among 228 men visiting the Facing Our Risk of Cancer Empowered or Craigslist website. Eligibility criteria included men who self-reported they had been tested for a BRCA mutation or had a partner or first degree relative tested for a BRCA mutation. A 41-item survey assessed socio-demographic, clinical characteristics, PGD knowledge and attitudinal factors and consideration of the use of PGD. Differences in proportions of subgroups were tested using the Monte Carlo exact test for categorical data. A multiple logistic regression model was then built through a backward elimination procedure. RESULTS: Although 80% of men reported being previously unfamiliar with PGD, after learning the definition of PGD, 34% of the 228 respondents then said they would 'ever consider the use of PGD'. Respondents who thought of PGD only in terms of 'health and safety' were almost three times more likely (OR = 2.82; 95% 1.19-6.71) to 'ever consider the use of PGD' compared with respondents who thought of PGD in terms of both 'health and safety', and 'religion and morality'. CONCLUSIONS: As with other anonymous web-based surveys, we cannot verify clinical characteristics that may impact consideration of PGD use. Our findings indicate high-risk men need more information about PGD and may benefit from educational materials to assist them in reproductive decision-making.

Off-pump versus on-pump coronary artery bypass grafting in consecutive patients: decision-making algorithm and outcomes.

BACKGROUND: Debate continues between on-pump or off-pump approach for coronary artery bypass grafting (CABG). We used off-pump coronary artery bypass grafting (OPCAB) as a tool within a decision-making algorithm driven by the patient-related factors of coronary anatomy and comorbidity. Our analysis presents this decision algorithm and describes outcomes using this approach. METHODS: From January 2000 to December 2003, 592 consecutive patients undergoing isolated CABG were assigned by one surgeon to a technique: on-pump CABG or OPCAB according to (1) anatomy and (2) predicted risk. Anatomic factors against OPCAB were target vessel size less than 1.25 mm, calcification, poor quality, intramyocardial location, and multiple stenoses. Given that OPCAB could be performed safely, patients in the moderate risk range, ie, those elderly with multiple comorbidities, were preferentially treated using OPCAB. RESULTS: The OPCAB group had higher predicted 30-day mortality compared with the on-pump CABG group, consistent with the protocol's intent. However, morbidity and mortality were similar between on-pump CABG and OPCAB. The OPCAB patients received the same number of internal mammary artery grafts but fewer distal grafts. Mortality and observed to expected ratios were favorable for both groups and below those The Society of Thoracic Surgeons' predicted for OPCAB. CONCLUSIONS: Matching surgical strategy to patient-related factors and needs resulted in excellent outcomes. Our data support the use of a protocol based on patient characteristics to drive the surgeon's choice between an on-pump CABG or OPCAB approach. As such, OPCAB can be viewed as a tool to be used by the surgeon developing a best practice in treating coronary artery disease.