Assessment of sources variability of riverine particulate organic matter with land use and rainfall changes using a three-indicator (δ13C, δ15N, and C/N) Bayesian mixing model.

In intensive agricultural watersheds, riverine particulate organic matter (POM) may be transported from many sources such as rice paddies, crop uplands, forests, and livestock farming areas during rainy seasons. However, the impacts of land-use and rainfall changes on the POM sources are not well understood. In this study, changes in the sources of riverine POM were investigated in an agricultural area of Korea between 2014 and 2020/21. During this period, land-use and rainfall patterns changed dramatically. The δ13C, δ15N, and C/N of the POM sources as well as those of riverine POM were analyzed, and a stable isotope analysis in R (SIAR) model was utilized for source apportionment. There were differences in δ13C, δ15N, and C/N among the sources. For example, manure had higher δ13C (-22.6 ± 3.3‰) and δ15N (+10.6 ± 5.9‰) than soils (from -28.0 ± 0.8‰ to -25.1 ± 1.2‰ for δ13C and +3.6 ± 1.7‰ to +9.8 ± 1.4‰ for δ15N). For soils, the δ13C and δ15N were higher for upland soils, while C/N was greater for forest soils than for others. For riverine POM, the δ15N marginally changed; however, the δ13C and C/N increased from -26.1 ± 0.9‰ to -20.8 ± 5.3‰ and from +7.7 ± 1.7 to +18.8 ± 8.3 between 2014 and 2020/21, respectively. The SIAR model showed that the contributions of paddy (from 41.0% to 14.9%) and upland fields (from 48.1% to 23.7%) to riverine POM decreased between the periods due to decreased paddy area and the implementation of best management practice on upland fields, respectively. However, the contribution of forests (from 3.5% to 28.0%) and manure (from 7.4% to 33.5%) increased probably due to improper management of forest clear-cutting sites and livestock manure storage sites. The contributions of agricultural soils to riverine POM decreased in drier years. Our study suggests that land management rather than land-use area is critical in riverine POM management, particularly in wetter years.

Rice straw cover decreases soil erosion and sediment-bound C, N, and P losses but increases dissolved organic C export from upland maize fields as evidenced by δ13C.

Soil surface with crop residue is effective in reducing soil erosion and carbon (C), nitrogen (N), and phosphorus (P) losses from sloping fields. However, there is a high possibility that surface cover increases export of dissolved organic C (DOC) though relevant field studies under natural rainfall are lacking. In this study, the effects of surface cover with rice (Oryza sativa L.) straw on soil and CNP losses in both dissolved and sediment-bound forms from maize (Zea mays L.) fields were investigated under two fertilization levels (standard and double) × two types of runoff experiments (natural rainfall and artificial irrigation). Changes in soil properties including moisture, temperature, nutrients, and C concentration as well as maize yield were also examined. Surface cover decreased soil and total CNP losses by up to 82% across the experimental plots with some exceptions. However, surface cover increased DOC export in both natural (by 68-82% in total across all events) and artificial (by 3-4 fold) runoff, suggesting that crop residue cover may act as a DOC pollution source of water bodies. The contribution of rice straw to DOC, which was calculated using the δ13C of DOC from covered plots (-24.1 to -28.0‰) and control plots (-19.6 to -25.1‰), was 52.5-95.8%. The concentrations of K2SO4-extractable and microbial biomass C of the soils did not differ between covered and control plots, suggesting that DOC produced from rice straw was not incorporated into the soils, but rather, was washed out with surface runoff in this study. Surface cover increased maize growth and yield, particularly in double fertilization plots, through improved soil moisture, temperature, and nutrient conditions. To take full advantage of surface cover with crop residue, a further study on reducing DOC loss from crop residue needs to be conducted.

Acupotomy versus Manual Acupuncture for the Treatment of Back and/or Leg Pain in Patients with Lumbar Disc Herniation: A Multicenter, Randomized, Controlled, Assessor-Blinded Clinical Trial.

BACKGROUND: Acupotomy, which involves the addition of a scalpel function to the conventional acupuncture treatment, has recently been applied as a conservative treatment method for lumbar disc herniation (LDH). This study investigated the effectiveness and safety of acupotomy, compared to manual acupuncture, for the treatment of patients with LDH. METHODS: A total of 146 patients diagnosed with LDH were randomly assigned to either the acupotomy group or the manual acupuncture group at a 1:1 ratio. Participants in both groups received four sessions of each intervention over 2 weeks. Outcome assessments based on the visual analog scale (VAS), Roland Morris Disability Questionnaire (RMDQ), Modified-Modified Schober Test (MMST), EuroQol Five Dimensions (EQ-5D), clinically important difference (CID), and patient global impression of change (PGIC) were conducted at baseline and at 2, 4, and 6 weeks post-randomization. RESULTS: The acupotomy group showed significant improvement in VAS and MMST at 2, 4, and 6 weeks than did the manual acupuncture group. RMDQ was significantly different between the two groups at 2 and 6 weeks. In EQ-5D, there was no significant difference between the two groups. The proportion of patients with ≥15 mm decrease on the VAS (minimal CID) was significantly higher in the acupotomy group at weeks 2 and 4. Better improvement in the PGIC at week 4 was also observed in the acupotomy group. Post-intervention muscle pain was reported, but there was no serious adverse event related to interventions. CONCLUSION: In this study, four sessions of acupotomy treatment were found to be effective in improving the pain intensity and range of motion of the lumbar region in patients with LDH. Despite post-treatment muscle pain, acupotomy treatment can be considered a preferred treatment method over manual acupuncture. TRIAL REGISTRATION: This trial has been registered 24 April 2018 in Clinical Research Information Service of South Korea (CRIS-KCT0002824).

Assessment of a green roof practice using the coupled SWMM and HYDRUS models.

Green roof can mitigate urban stormwater and improve environmental, economic, and social conditions. Various modeling approaches have been effectively employed to implement a green roof, but previous models employed simplifications to simulate water movement in green roof systems. To address this issue, we developed a new modeling tool (SWMM-H) by coupling the stormwater management and HYDRUS-1D models to improve simulations of hydrological processes. We selected green roof systems to evaluate the coupled model. Rainfall-runoff experiments were conducted for a pilot-scale green roof and urban subbasin. Soil moisture in the green roof and runoff volume in the subbasin were simulated more accurately by using SWMM-H instead of SWMM. The scenario analysis showed that SWMM-H selected sandy loam for controlling runoff whereas SWMM recommended sand. In conclusion, SWMM-H could be a useful tool for accurately understanding hydrological processes in green roofs.

Effectiveness and safety of acupotomy for treating back and/or leg pain in patients with lumbar disc herniation: A study protocol for a multicenter, randomized, controlled, clinical trial.

BACKGROUND: As the number of patients suffering from back and/or leg pain due to lumbar disc herniation (LDH) is increasing in Korea, conservative treatments for patients with LDH have been spotlighted. Although several studies have been published on the use of acupotomy for the treatment of such patients, most of them are only case studies. Therefore, the purpose of this study is to compare the effectiveness and safety of acupotomy to those for manual acupuncture for the treatment of patients with LDH. METHODS/DESIGN: This study is planned as a multicenter, parallel design, randomized, controlled, clinical study. One hundred forty-six patients diagnosed with LDH will be randomly assigned to either the acupotomy group or the manual acupuncture group at a 1:1 ratio. Participants in both groups will receive a total of 4 interventions over 2 weeks. An effectiveness assessment based on the outcomes on the visual analog scale (VAS), Roland Morris Disability Questionnaire (RMDQ), Modified-Modified Schober Test (MMST), EuroQol Five Dimensions (EQ-5D), and Patient Global Impression of Change (PGIC) will be conducted at baseline and at 2, 4, and 6 weeks postrandomization. The primary outcome will be the mean change in the VAS for back and/or leg pain 4 weeks postrandomization. Adverse events will be recorded at every visit. DISCUSSION: The results of this study will provide evidence for the effectiveness and safety of acupotomy treatment for patients with LDH. TRIAL REGISTRATION: Clinical Research Information Service of South Korea (CRIS- KCT0002824), April 24, 2018.

An effective methodology for simultaneous quantification of thiophanate-methyl, and its metabolite carbendazim in pear, using LC-MS/MS.

Herein we have developed an optimized analytical method for the simultaneous quantification of a fungicide, thiophanate-methyl, and its metabolite, carbendazim, in pear cultivated under open-field conditions using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Due to the problem of partitioning associated with using acetonitrile and salts, methanol was used for sample extraction; the extract was then filtered using a vacuum filter, and cleaned-up using C18 QuEChERS bulk sorbent following dispersive solid-phase extraction (d-SPE) procedure. Since a common problem, "matrix effect", associated with the matrix was observed in LC-MS/MS, calibration curves for both thiophanate-methyl and carbendazim were constructed in the matrix using seven different concentration levels. Excellent linearity was observed, with determinant coefficient (R2) ≥ 0.9990. The limits of quantification (LOQs) were ≤0.02 mg/kg, satisfactory in terms of the maximum residue limits. Methods were validated at two fortification concentrations (10 × LOQ and 50 × LOQ); the experiments were repeated three times for each level and the average recoveries were 75.00-84.92%, with the coefficient of variation (CV) being ≤5.78%. The developed analytical method was applied to pear samples previously sprayed with commercial thiophanate-methyl formulation four times on different days during pre-harvest treatment. The parent compound was converted to its metabolites and the total residues degraded continuously until harvest. The data obtained in this study could help set safety guidelines for thiophanate-methyl in pear.

Optimizing low impact development (LID) for stormwater runoff treatment in urban area, Korea: Experimental and modeling approach.

Currently, continued urbanization and development result in an increase of impervious areas and surface runoff including pollutants. Also one of the greatest issues in pollutant emissions is the first flush effect (FFE), which implies a greater discharge rate of pollutant mass in the early part in the storm. Low impact development (LID) practices have been mentioned as a promising strategy to control urban stormwater runoff and pollution in the urban ecosystem. However, this requires many experimental and modeling efforts to test LID characteristics and propose an adequate guideline for optimizing LID management. In this study, we propose a novel methodology to optimize the sizes of different types of LID by conducting intensive stormwater monitoring and numerical modeling in a commercial site in Korea. The methodology proposed optimizes LID size in an attempt to moderate FFE on a receiving waterbody. Thereby, the main objective of the optimization is to minimize mass first flush (MFF), which is an indicator for quantifying FFE. The optimal sizes of 6 different LIDs ranged from 1.2 mm to 3.0 mm in terms of runoff depths, which significantly moderate the FFE. We hope that the new proposed methodology can be instructive for establishing LID strategies to mitigate FFE.

Development of a multiresidue method for the determination of multiclass pesticides in soil using GC.

The principal objective of the present study was to develop a multiresidue analytical method for 62 pesticides in a soil matrix. Soil samples were fortified with known quantities of pesticides at two different concentration levels (0.1 and 0.01 microg/g) and the analytes were extracted via a liquid-solid extraction method. The pesticides were separated on an HP5 capillary column and were detected by gas chromatography coupled to an electron capture detector (GC-ECD). The method was validated, considering its good linearities (r(2) = 0.978-0.999), specificity and recovery characteristics. Recoveries were found between 70.3 and 113.4% for all pesticides except edifenphos (67.5%) and dichlobenil (69.5%) spiked at a 0.1 microg/mL concentration level and 74.5-117% except ethalfluralin (63.3%) and dichlobenil (51.9%) spiked at a concentration of 0.01 microg/mL. The developed method could be utilized as a simple and cost-effective method for the routine analysis of 62 pesticides in soil samples.

Changes in nitrogen isotopic compositions during composting of cattle feedlot manure: effects of bedding material type.

Temporal changes in delta(15)N of cattle feedlot manure during its composting with either rice hull (RHM) or sawdust (SDM) as bedding materials were investigated. Regardless of the bedding material used, the delta(15)N of total N in the manure increased sharply from +7.6 per thousand to +9.9 per thousand and from +11.4 per thousand to +14.3 per thousand, respectively, in RHM or SDM, within 10 days from the commencement of composting. Such increases could be attributed primarily to N loss via NH(3) volatilization and denitrification based on the very high delta(15)N values (greater than +20 per thousand) of NH(4)(+) and NO(3)(-) in the co-composted manure. The delta(15)N of total N in RHM was substantially lower (by more than 3 per thousand) than that in SDM, suggesting that the delta(15)N of the composted manure was affected not only by N loss but also by the type of bedding material used. Specifically, the higher N concentration in the rice hull than in the saw dust could lead to a greater (15)N isotope dilution.