Denitrifying bioreactors and dissolved phosphorus: Net source or sink?

Understanding the world through a lens of phosphorus (P), as Dr. Andrew Sharpley aimed to do, adds a deeper dimension for water quality work in the heavily tile-drained US Midwest where nitrate is often the nutrient of biggest concern. Denitrifying woodchip bioreactors reduce nitrate pollution in drainage water, but dissolved phosphorus leached from the organic fill is a possible pollution tradeoff. Recent work by Dr. Sharpley and others defined such tradeoffs as strategic decisions in which a negative outcome is accepted with prior knowledge of the risk. In this vein, we assessed 23 site-years from full-size bioreactors in Illinois to determine if bioreactors were a net dissolved reactive phosphorus (DRP) source and, if so, to determine flow-related correlation agents (1904 sample events; 10 bioreactors). DRP was removed across the bioreactors in 15 of 23 site-years. The 23 site-years provided a median annual DRP removal efficiency of 12% and a median annual DRP removal rate of 7.1 mg DRP/m3 bioreactor per day, but the ranges of all removal metrics overlapped zero. The highest daily bioreactor DRP removal rates occurred with high inflow concentrations and under low hydraulic retention times (i.e., under higher loading). Dr. Sharpley was one of the first to explore losses of DRP in subsurface drainage and performed decades of useful applied studies that inspired approaches to management of P loss on both drained and undrained land. We seek to honor this legacy with this practical study of the DRP benefits and tradeoffs of denitrifying bioreactors.

Impact of P inputs on source-sink P dynamics of sediment along an agricultural ditch network.

Phosphorus (P) loss from intensive dairy farms is a pressure on water quality in agricultural catchments. At farm scale, P sources can enter in-field drains and open ditches, resulting in transfer along ditch networks and delivery into nearby streams. Open ditches could be a potential location for P mitigation if the right location was identified, depending on P sources entering the ditch and the source-sink dynamics at the sediment-water interface. The objective of this study was to identify the right location along a ditch to mitigate P losses on an intensive dairy farm. High spatial resolution grab samples for water quality, along with sediment and bankside samples, were collected along an open ditch network to characterise the P dynamics within the ditch. Phosphorus inputs to the ditch adversely affected water quality, and a step change in P concentrations (increase in mean dissolved reactive phosphorus (DRP) from 0.054 to 0.228 mg L-1) midway along the section of the ditch sampled, signalled the influence of a point source entering the ditch. Phosphorus inputs altered sediment P sorption properties as P accumulated along the length of the ditch. Accumulation of bankside and sediment labile extractable P, Mehlich 3 P (M3P) (from 13 to 97 mg kg-1) resulted in a decrease in P binding energies (k) to < 1 L mg-1 at downstream points and raised the equilibrium P concentrations (EPC0) from 0.07 to 4.61 mg L-1 along the ditch. The increase in EPC0 was in line with increasing dissolved and total P in water, demonstrating the role of sediment downstream in this ditch as a secondary source of P to water. Implementation of intervention measures are needed to both mitigate P loss and remediate sediment to restore the sink properties. In-ditch measures need to account for a physicochemical lag time before improvements in water quality will be observed.

Assessment and Synthesis of 50 Years of Published Drainage Phosphorus Losses.

The prevalence of anthropogenic drainage systems in intensively cropped areas across North America combined with the degradation of important freshwater resources in these regions has created a critical intersection where understanding phosphorus (P) transport in drainage waters is vital. In this study, drainage-associated nutrient load data were retrieved and quantitatively analyzed to develop a more comprehensive understanding of the P loading and crop yield impacts of agronomic management practices within drained landscapes. Using the Drain Load table in the MANAGE (Measured Annual Nutrient loads from AGricultural Environments) database, the effect of factors such as soil characteristics, tillage, and nutrient management on P loading were analyzed. Across site-years, generally less than 2% of applied P was lost in drainage water, which corroborates the order of magnitude difference between agronomic P application rates and P loadings that can cause deleterious water quality impacts. The practice of no-till significantly increased drainage dissolved P loads compared with conventional tillage (0.12 vs. 0.04 kg P ha). The timing and method of P application are both known to be important for P losses, but these conclusions could not be verified due to low site-year counts. Findings indicate there is a substantial need for additional field-scale studies documenting not only P losses in drainage water but also important cropping management, nutrient application, soil property, and drainage design impacts on such losses.

The effects of iodine blocking on thyroid cancer, hypothyroidism and benign thyroid nodules following nuclear accidents: a systematic review.

A potential radiation protection method to reduce the risk of adverse health outcomes in the case of accidental radioactive iodine release is the administration of potassium iodide (KI). Although KI administration is recommended by WHO's Guidelines for Iodine Prophylaxis following Nuclear Accidents, a systematic review of the scientific evidence for the guidelines is lacking. Therefore, this study aims to systematically review the effects of KI administration in the case of accidental radioactive iodine release on thyroid cancer, hypothyroidism and benign thyroid nodules. We applied standard systematic review methodology for a search of the literature, selection of eligible studies, data extraction, assessment of risk of bias, assessment of heterogeneity, data synthesis, and the assessment of the quality of the evidence. We searched MEDLINE (via PubMed) and EMBASE. We found one cross-sectional study, one analytic cohort study and two case-control studies relating to our question. The number of participants ranged from 886-12 514. Two studies were conducted in children and two other studies in children and adults. It was not possible to conduct a meta-analysis. We identified low to very low-quality evidence that KI administration after a nuclear accident resulted in a reduction of the risk of thyroid cancer in children; however, the KI administration and dose was not well described in the studies. None of the studies investigated the effects of KI administration in the case of a nuclear accident on hypothyroidism and benign thyroid nodules. Low to very low-quality evidence suggests that KI intake following a nuclear accident may reduce the risk of thyroid cancer in children. No conclusions can be drawn about the effectiveness of KI intake with respect to the prevention of hypothyroidism and benign thyroid nodules.

4R Water Quality Impacts: An Assessment and Synthesis of Forty Years of Drainage Nitrogen Losses.

The intersection of agricultural drainage and nutrient mobility in the environment has led to multiscale water quality concerns. This work reviewed and quantitatively analyzed nearly 1,000 site-years of subsurface tile drainage nitrogen (N) load data to develop a more comprehensive understanding of the impacts of 4R practices (application of the right source of nutrients, at the right rate and time, and in the right place) within drained landscapes across North America. Using drainage data newly compiled in the "Measured Annual Nutrient loads from AGricultural Environments" (MANAGE) database, relationships were developed across N application rates for nitrate N drainage loads and corn ( L.) yields. The lack of significant differences between N application timing or application method was inconsistent with the current emphasis placed on application timing, in particular, as a water quality improvement strategy ( = 0.934 and 0.916, respectively). Broad-scale analyses such as this can help identify major trends for water quality, but accurate implementation of the 4R approach will require site-specific knowledge to balance agronomic and environmental goals.

Risk factors for perineal injury during delivery.

OBJECTIVE: We sought to identify risk factors for anal sphincter injury during vaginal delivery. STUDY DESIGN: This was a retrospective, case-control study. We reviewed 2078 records of vaginal deliveries within a 2-year period from May 1, 1999, through April 30, 2001. Cases (n = 91) during the study period were defined as parturients who had documentation of greater than a second-degree perineal injury. Control subjects (n = 176), who were identified with the use of a blinded protocol, included women who were delivered vaginally with less than or equal to a second-degree perineal injury. For each patient, we reviewed medical and obstetrics records for the following characteristics: maternal age, race, weight, gestational age, parity, tobacco use, duration of first and second stages of labor, use of oxytocin, use of forceps or vacuum, infant birth weight, epidural use, and episiotomy use. RESULTS: Of the 2078 deliveries that were reviewed, we discovered 91 cases (4.4%) of documented anal sphincter injury. The mean maternal age of our sample was 24.9 +/- 5.9 years). Nearly two thirds (63.2%) were white; 26.7% were black, and 10.1% were of other racial backgrounds. Forceps were used in 51.6% of deliveries that resulted in tears (cases), compared to 8.6% of deliveries without significant tears (control subjects, P <.05). Using cases and control subjects with complete data (cases, 82; control subjects, 144), delivery with forceps was associated with a 10-fold increased risk of perineal injury (odds ratio, 10.8; 95% CI, 5.2-22.3) compared to noninstrumented deliveries. The association was similar after adjustment for age, race, parity, mode of delivery, tobacco use, episiotomy, duration of labor (stages 1 and 2), infant birth weight, epidural, and oxytocin use (odds ratio, 11.9; 95% CI, 4.7-30.4). Nulliparous women were at increased risk for tears (adjusted odds ratio, 10.0; 95% CI, 3.0-33.3) compared with multiparous patients, but parity did not reduce the association between forceps-assisted deliveries and anal sphincter injuries. Increasing fetal weight was also a risk factor in both unadjusted and adjusted analyses. The performance of a midline episiotomy was associated with an increased risk of anal sphincter tear compared with delivery without an episiotomy in the univariate analysis (odds ratio, 4.9; 95% CI, 2.5-9.6), but this association was reduced in the adjusted analysis (odds ratio, 2.5; 95% CI, 1.0-6.0). The increased duration of both the first and second stages of labor increased injury risk in the unadjusted, but not adjusted, analysis. No significant association was observed between case status and the use of oxytocin or epidural anesthesia. Greater, but not significant, increased risk was associated with maternal indications for operative delivery compared with fetal indications. CONCLUSION: Our results are consistent with recent reports that identify forceps delivery and nulliparity as risk factors for recognized anal sphincter injury at the time of vaginal delivery. Further investigation should focus on the determination of whether the association of injury to instrumentation is causal or, in fact, modifiable. Because of the established association between sphincteric muscular damage and anal incontinence, patients should be counseled about the risk of anal sphincter injury when operative vaginal delivery is contemplated. Such patients should be followed closely in the postpartum setting to assess for the development of potential anorectal complaints.

Deletion of the trichodiene synthase gene of Fusarium venenatum: two systems for repeated gene deletions.

The trichodiene synthase (tri5) gene of Fusarium venenatum was cloned from a genomic library. Vectors were created in which the tri5 coding sequence was replaced with the Neurospora crassa nitrate reductase (nit3) gene and with the Aspergillus nidulans acetamidase (amdS) gene flanked by direct repeats. The first vector was utilized to transform a nitrate reductase (niaD) mutant of F. venenatum to prototrophy, and the second vector was utilized to confer acetamide utilization to the wild-type strain. Several of the transformants lost the capacity to produce the trichothecene diacetoxyscirpenol and were shown by hybridization analysis to have gene replacements at the tri5 locus. The nit3 gene was removed by retransformation with a tri5 deletion fragment and selection on chlorate. The amdS gene was shown to excise spontaneously via the flanking direct repeats when spores were plated onto fluoroacetamide.

Species-specific primers resolve members of Fusarium section Fusarium. Taxonomic status of the edible "Quorn" fungus reevaluated.

Sixty-seven authentic isolates, representing six species from Fusarium section Fusarium (= section Discolor) were subjected to random amplified polymorphic DNA (RAPD) analysis and polymerase chain reaction using species-specific primers. Remarkably uniform RAPD banding patterns were obtained intraspecifically, irrespective of the geographical origin of the isolates or the host/substratum from which they were isolated. Isolates were also assessed for colony characteristics when grown on a defined minimal medium. The Quorn strain (ATCC 20334; previously considered to be F. graminearum) matched the F. venenatum strains exclusively in RAPD profile. In addition, equivalently sized DNA fragments amplified from ATCC 20334 and two authentic F. venenatum strains were identical with respect to DNA sequence. Our molecular and morphological data support the identification of the Quorn strain as F. venenatum Nirenberg (= F. sambucinum Fuckel sensu lato).

Residue-based control of helix shape in beta-peptide oligomers.

Proteins and RNA are unique among known polymers in their ability to adopt compact and well-defined folding patterns. These two biopolymers can perform complex chemical operations such as catalysis and highly selective recognition, and these functions are linked to folding in that the creation of an active site requires proper juxtaposition of reactive groups. So the development of new types of polymeric backbones with well-defined and predictable folding propensities ('foldamers') might lead to molecules with useful functions. The first step in foldamer development is to identify synthetic oligomers with specific secondary structural preferences. Whereas alpha-amino acids can adopt the well-known alpha-helical motif of proteins, it was shown recently that beta-peptides constructed from carefully chosen beta-amino acids can adopt a different, stable helical conformation defined by interwoven 14-membered-ring hydrogen bonds (a 14-helix; Fig. 1a). Here we report that beta-amino acids can also be used to design beta-peptides with a very different secondary structure, a 12-helix (Fig. 1a). This demonstrates that by altering the nature of beta-peptide residues, one can exert rational control over the secondary structure.

Comparison of oral and intramuscular preanesthetic medication for pediatric inpatient surgery.

The child's fear of injections coupled with the concern that the psychologic advantage of intramuscular premedication may be all or in part negated by the trauma of injections prompted the authors to seek an oral preanesthetic medication to safely and reliably replace injections. The authors describe the results of a prospective, randomized, double-blind study comparing the pharmacologic effects of oral versus injectable preanesthetic medication in 67 healthy pediatric inpatients older than 1 yr. Children given the oral medication (meperidine 3.0 mg/kg, pentobarbital 4.0 mg/kg) were significantly more drowsy in the holding area (P less than 0.001) and more cooperative at the time of induction of anesthesia (P less than 0.01) than the children given intramuscular medication (morphine 0.1 mg/kg, pentobarbital 4.0 mg/kg). There were no other differences between the two groups. These data demonstrate that oral preanesthetic medication can be as or more effective compared with intramuscular medication in producing the desired effects without adverse side effects. As a result of this study, the benefits of preanesthetic medication can now be achieved in nearly all surgical patients without injections.

Pneumococcal infection and immunologic response to pneumococcal vaccine in chronic obstructive pulmonary disease. A pilot study.

We assessed the importance of Streptococcus pneumoniae and immunologic response to 14-valent pneumococcal vaccine in a randomized (saline placebo or vaccine) double-blind pilot study involving 103 patients with chronic obstructive pulmonary disease (COPD). Antibody titers, the flora of the sputum, respiratory infections or pneumonias, and deaths were monitored. The patients' antibody titers before immunization were higher than healthy control subjects. Titers rose normally in those vaccinated but declined more rapidly. Differences between the group receiving placebo and vaccine were not significant at 12 and 24 months. The incidence of pneumonia was high before and after vaccine (47/1,000 vs 41/1,000 patient-years). Nonpneumococcal causes predominated (73 percent of pneumonias; 83.4 percent of lethal pneumonias). Isolates from sputum were predominantly nonvaccine types (50 to 62.5 percent). Twenty-seven patients died; pneumonia occurred in six (one pneumococcal in a vaccinated patient) as a terminal complication of other diseases. Thus, although pneumonia occurred frequently in these patients with COPD and contributed to mortality in 22 percent (six) of the 27 deaths, the predominance of nonpneumococcal causes and the data on antibodies and sputum suggest that pneumococcal vaccine may not be as beneficial for patients with COPD as was hoped. More observations are needed.

Acute carcinoid syndrome: a complication of flexible fiberoptic bronchoscopy.

We report the case of a patient with functioning bronchial carcinoid tumor found as a solitary nodule. Acute carcinoid syndrome developed during transbronchial biopsy, and life-threatening hypotension occurred during operation. We emphasize that carcinoid tumors should be considered in the differential diagnosis of solitary nodules, and such a complication should be kept in mind when endobronchial or transbronchial biopsy is performed.