530 research outputs found
Organic Amendments to Enhance Herbicide Biodegradation in Contaminated Soils
Pesticide contamination of soil and groundwater at agricultural chemical distribution sites is a widespread problem in the USA. Alternatives to land-farming or solid waste disposal include biostimulation and phytoremediation. This research investigated the ability of compost, corn stalks, corn fermentation byproduct, peat, manure, and sawdust at rates of 0.5% and 5% (w/w) to stimulate biodegradation of atrazine [6-chloro-N-ethyl-N′-(1-methyethyl)-1,3,5-triazine-2,4-diamine], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], and trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] added as a mixture to soil. Initial concentrations were 175±42 mg atrazine kg–1 soil, 182±25 mg metolachlor kg–1 soil, and 165±23 mg trifluralin kg–1soil. After amendment addition, 30% of the atrazine, 33% of the metolachlor, and 44% of the trifluralin was degraded over 245 days, which included 63 days\u27 aging prior to amendment additions. Atrazine degradation was enhanced by 0.5% manure, 5% peat, and 5% cornstalk amendments compared to nonamended soils. Metolachlor degradation was enhanced by all amendments at the 5% level, except for compost and peat. Amendments had no effect on trifluralin degradation. The 5% addition of compost, manure, and cornstalks resulted in significant increases in bacterial populations and dehydrogenase activity. A second experiment compared the persistence of atrazine, metolachlor, and trifluralin applied in a mixture to their persistence in soil individually. A combined average of 123 mg atrazine kg–1 remained in soil treated with the three-herbicide mixture compared to 31 mg atrazine kg–1 remaining in soil treated with atrazine only. Atrazine mineralization and atrazine-degrading microorganisms were suppressed by high concentrations of metolachlor, but not by trifluralin
Review of eprodisate for the treatment of renal disease in AA amyloidosis
Secondary (AA) amyloidosis is a multisystem disorder complicating chronic infections or inflammatory diseases. It is characterized by extracellular deposit of fibrils composed of fragments of serum amyloid A (SAA), an acute phase reactant protein. The kidney is the most frequent organ involved, manifesting as progressive proteinuria and renal impairment. Attenuation of the level of circulating SAA protein by treating the underlying inflammatory condition remains the primary strategy in treating AA amyloidosis. However, at times, achieving adequate control of protein production can prove difficult. In addition, relapse of renal function often occurs rapidly following any subsequent inflammatory stimulus in patients with existing amyloidosis. Recently there has been an interest in finding other potential strategies targeting amyloid deposits themselves. Eprodisate is a sulfonated molecule with a structure similar to heparan sulfate. It competitively binds to the glycosaminoglycan-binding sites on SAA and inhibits fibril polymerization and amyloid deposition. Recent randomized clinical trial showed that it may slow down progressive renal failure in patients with AA amyloidosis. However confirmatory studies are needed and results of a second Phase III study are eagerly awaited to clarify whether or not eprodisate has a place in treating renal amyloid disease
Anthropomorphic Simulations of Falls, Shakes, and Inflicted Impacts in Infants
Object: Rotational loading conditions have been shown to produce subdural hemorrhage and diffuse axonal injury. No experimental data are available with which to compare the rotational response of the head of an infant during accidental and inflicted head injuries. The authors sought to compare rotational deceleration sustained by the head among free falls, from different heights onto different surfaces, with those sustained during shaking and inflicted impact.
Methods: An anthropomorphic surrogate of a 1.5-month-old human infant was constructed and used to simulate falls from 0.3 m (1 ft), 0.9 m (3 ft), and 1.5 m (5 ft), as well as vigorous shaking and inflicted head impact. During falls, the surrogate experienced occipital contact against a concrete surface, carpet pad, or foam mattress. For shakes, investigators repeatedly shook the surrogate in an anteroposterior plane; inflicted impact was defined as the terminal portion of a vigorous shake, in which the surrogate’s occiput made contact with a rigid or padded surface. Rotational velocity was recorded directly and the maximum (peak–peak) change in angular velocity ( max) and the peak angular acceleration ( max) were calculated. Analysis of variance revealed significant increases in the max and max associated with falls onto harder surfaces and from higher heights. During inflicted impacts against rigid surfaces, the max and max were significantly greater than those measured under all other conditions.
Conclusions: Vigorous shakes of this infant model produced rotational responses similar to those resulting from minor falls, but inflicted impacts produced responses that were significantly higher than even a 1.5-m fall onto concrete. Because larger accelerations are associated with an increasing likelihood of injury, the findings indicate that inflicted impacts against hard surfaces are more likely to be associated with inertial brain injuries than falls from a height less than 1.5 m or from shaking
Occurrence of Atrazine and Degradates as Contaminants of Subsurface Drainage and Shallow Groundwater
Atrazine is a commonly used herbicide in corn (Zea mays L.) growing areas of the USA. Because of its heavy usage, moderate persistence, and mobility in soil, monitoring of atrazine movement under field conditions is essential to assess its potential to contaminate groundwater. Concentrations of atrazine, deisopropylatrazine (DIA), and deethylatrazine (DEA) were measured in subsurface drainage and shallow groundwater beneath continuous, no-till corn. Water samples were collected from the subsurface drain (tile) outlets and suction lysimeters in the growing seasons of 1990 and 1991, and analyzed for atrazine and two principle degradates using solid-phase extraction and HPLC. In 1990, atrazine concentration ranged from 1.3 to 5.1 µg L−1 in tile-drain water and from 0.5 to 20.5 µg L−1 in lysimeter water. In general, concentrations of parent and degradates in solution were atrazine \u3e DEA \u3e DIA. Lesser levels of atrazine were measured in 1991 from Plots 2 and 4; however, greater concentrations of atrazine (6.0–8.4 µg L−1) were measured from Plot 5. Throughout the two growing seasons, atrazine concentration in Plot 5 tile-drain water was greater than that of Plots 2 and 4, suggesting a preferential movement of atrazine. Concentrations of DIA and DEA ranged from 0.1 to 2.2 and 0.9 to 3.2 µg L−1, respectively, indicating that the degradation products by themselves or in combination with parent atrazine can exceed the maximum contaminant level (mcl) of 3 µg L−1 even though atrazine by itself may be \u3c3 µg L−1. The deethylatrazineto-atrazine ratio (DAR) is an indicator of residence time in soil during transport of atrazine to groundwater. In Plots 2 and 4, DAR values for tile-drain water ranged from 0.43 to 2.70 and 0.50 to 2.66, respectively. By comparison, a DAR of 0.38 to 0.60 was observed in Plot 5, suggesting less residence time in the soil
High-Tide Floods and Storm Surges During Atmospheric Rivers on the US West Coast
Amospheric rivers (ARs) effect inland hydrological impacts related to extreme precipitation. However, little is known about the possible coastal hazards associated with these storms. Here we elucidate high-tide floods (HTFs) and storm surges during ARs through a statistical analysis of data from the US West Coast during 1980-2016. HTFs and landfalling ARs co-occur more often than expected from random chance. Between 10%-63% of HTFs coincide with landfalling ARs, depending on location. However, only 2%-15% of ARs coincide with HTFs, suggesting that ARs typically must co-occur with anomalously high tides or mean sea levels to cause HTFs. Storm surges during ARs are interpretable in terms of local wind, pressure, and precipitation forcing. Meridional wind and barometric pressure are the primary drivers of the storm surge. This study highlights the relevance of ARs to coastal impacts, clarifies the drivers of storm surge during ARs, and identifies future research directions
Projected drought risk in 1.5°C and 2°C warmer climates
The large socioeconomic costs of droughts make them a crucial target for impact assessments of climate change scenarios. Using multiple drought metrics and a set of simulations with the Community Earth System Model targeting 1.5°C and 2°C above preindustrial global mean temperatures, we investigate changes in aridity and the risk of consecutive drought years. If warming is limited to 2°C, these simulations suggest little change in drought risk for the U.S. Southwest and Central Plains compared to present day. In the Mediterranean and central Europe, however, drought risk increases significantly for both 1.5°C and 2°C warming targets, and the additional 0.5°C of the 2°C climate leads to significantly higher drought risk. Our study suggests that limiting anthropogenic warming to 1.5°C rather than 2°C, as aspired to by the Paris Climate Agreement, may have benefits for future drought risk but that such benefits may be regional and in some cases highly uncertain
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Aging is associated with positive responding to neutral information but reduced recovery from negative information
Studies on aging and emotion suggest an increase in reported positive affect, a processing bias of positive over negative information, as well as increasingly adaptive regulation in response to negative events with advancing age. These findings imply that older individuals evaluate information differently, resulting in lowered reactivity to, and/or faster recovery from, negative information, while maintaining more positive responding to positive information. We examined this hypothesis in an ongoing study on Midlife in the US (MIDUS II) where emotional reactivity and recovery were assessed in a large number of respondents (N = 159) from a wide age range (36–84 years). We recorded eye-blink startle magnitudes and corrugator activity during and after the presentation of positive, neutral and negative pictures. The most robust age effect was found in response to neutral stimuli, where increasing age is associated with a decreased corrugator and eyeblink startle response to neutral stimuli. These data suggest that an age-related positivity effect does not essentially alter the response to emotion-laden information, but is reflected in a more positive interpretation of affectively ambiguous information. Furthermore, older women showed reduced corrugator recovery from negative pictures relative to the younger women and men, suggesting that an age-related prioritization of well-being is not necessarily reflected in adaptive regulation of negative affect
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