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Hybrid materials based on deep eutectic solvents for the preconcentration of formaldehyde by SPME in coffee beverages. Talanta 2024; 268:125309. [PMID: 37871466 DOI: 10.1016/j.talanta.2023.125309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/20/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023]
Abstract
Coffee is one of the most widely consumed beverages. It can be prepared from green or roasted beans or from instant coffee. Unfortunately, in addition to the aroma obtained in the coffee roasting process, among others, formaldehyde can be produced. In this study, thin-film solid-phase microextraction was used to preconcentrate trace amounts of formaldehyde in different types of coffee with different roasting levels. For this purpose, 18 hybrid materials based on deep eutectic solvents were synthesized and tested as sorbents in thin-film solid-phase microextraction. The coffee samples were brewed, and then formaldehyde present in them was derivatized using the Nash reagent. The sample preparation procedure was optimized for selected DES-based sorbent using a central composite design method and validated. Formaldehyde was determined in almost all samples of second-crack coffee (roasted at 240 °C) at 0.17-0.75 ng mL-1 and in darker-colored instant coffees at 0.18-0.54 ng mL-1.
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Sorption of ionic liquids in soil enriched with polystyrene microplastic reveals independent behavior of cations and anions. CHEMOSPHERE 2023; 341:139927. [PMID: 37633614 DOI: 10.1016/j.chemosphere.2023.139927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/28/2023]
Abstract
Recently, much attention has been focused on the application of the Ionic Liquids (ILs) with herbicidal activity in agriculture. It has been suggested that through the appropriate selection of cations and anions, one can adjust the properties of ILs, particularly the hydrophobicity, solubility, bioavailability, toxicity. In practical agricultural conditions, it will be beneficial to reduce the mobility of herbicidal anions, such as the commonly applied 2,4-dichlorophenoxyacetic acid [2,4-D] in the soil. Furthermore, microplastics are becoming increasingly prevalent in the soil, potentially stimulating herbicidal sorption. Therefore, we investigated whether cations in ILs influence the mobility of anions in OECD soil supplemented with polystyrene microplastic (PS). For this purpose, we used the 2,4-D based ILs consisting of: a hydrophilic choline cation [Chol][2,4-D] and a hydrophobic choline cation with a C12chain [C12Chol][2,4-D]. Characterization of selected micropolystyrene was carried out using the BET sorption-desorption isotherm, particle size distribution and changes in soil sorption parameters such as soil sorption capacity and cation exchange capacity. Based on the batch sorption experiment, the effect of microplastic on the sorption of individual cations and anions in soil contaminated with micropolystyrene was evaluated. The results obtained indicate that the introduction of a 1-10% (w/w) PS resulted in an 18-23% increase of the soil sorption capacity. However, the sorption of both ILs' cations increased only by 3-5%. No sorption of the [2,4-D] anion was noted. This suggests that cations and anions forming ILs, behave independently of each other in the environment. The results indicate the fact that ILs upon introduction into the environment are not a new type of emerging contaminant, but rather a typical mixture of ions. It is worth noting that when analyzing the behavior of ILs in the environment, it is necessary to follow the fate of both cations and anions.
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2,4-D versus 2,4-D based ionic liquids: Effect of cation on herbicide biodegradation, tfdA genes abundance and microbiome changes during soil bioaugmentation. JOURNAL OF HAZARDOUS MATERIALS 2023; 452:131209. [PMID: 36940526 DOI: 10.1016/j.jhazmat.2023.131209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/22/2023] [Accepted: 03/12/2023] [Indexed: 05/03/2023]
Abstract
The commercial formulations of herbicides rely on surfactants which increase the efficiency of active substance. Herbicidal ionic liquids (ILs), in which cationic surfactants are combined with herbicidal anions, allow for additives' reduction and ensure very good herbicide performance with lower doses. We aimed to test the impact of synthetic and natural cations on biological degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). Although primary biodegradation was high, the mineralization in agricultural soil indicated incomplete conversion of ILs to CO2. Even the introduction of naturally-derived cations resulted in an increase in the herbicide's half-lives - from 32 days for [Na][2,4-D] to 120 days for [Chol][2,4-D] and 300 days for the synthetic tetramethylammonium derivative [TMA][2,4-D]. Bioaugmentation with 2,4-D-degrading strains improves the herbicides' degradation, which was reflected by higher abundance of tfdA genes. Microbial community analysis confirmed that hydrophobic cationic surfactants, even those based on natural compounds, played a negative role on microbial biodiversity. Our study provides a valuable indication for further research related to the production of a new generation of environmentally friendly compounds. Moreover, the results shed a new light on the ionic liquids as independent mixtures of ions in the environment, as opposed to treating them as new type of environmental pollutants.
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Application of phosphonium deep eutectic solvents as extractants in ultrasound-assisted dispersive liquid-liquid microextraction for preconcentration of trace amounts of herbicides in drainage ditches waters. J Sep Sci 2023; 46:e2200682. [PMID: 36373174 DOI: 10.1002/jssc.202200682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/09/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022]
Abstract
In this study, an efficient preconcentration method was presented that is based on dispersive liquid-liquid microextraction taking the advantage of newly synthesized phosphonium deep eutectic solvents used as extractants and ultrasound probe as a dispersing agent. The extracts obtained were analyzed by high-performance liquid chromatography. To optimize the five most important factors for the microextraction procedure a central composite design plan was used. Under optimal conditions (140 μl of extractant, 60 mg of NaCl, pH = 2.0, 120 s of extraction time with ultrasound probe as the dispersing agent, 16 min of centrifugation for phase separation), the proposed method allowed to achieve good precision with RSD between 3.2% and 9.7% at 1.0, 5.0 and 40.0 ng ml levels. The preconcentration factors were equal to 42, 39, and 41, and the limits of detection 0.128, 0.103, and 0.135 ng/ml for dicamba, 2-methyl-4-chlorophenoxyacetic acid, and 2-methyl-4-chlorophenoxypropionic acid, respectively. The proposed method was successfully applied for the determination of chlorophenoxy acid herbicides in water samples from drainage ditches with a good recovery in the range of 70%-93%.
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Comprehensive Analysis of Metabolites in Brews Prepared from Naturally and Technologically Treated Coffee Beans. Antioxidants (Basel) 2022; 12:antiox12010095. [PMID: 36670958 PMCID: PMC9855040 DOI: 10.3390/antiox12010095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/25/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
Coffee is one of the most popular beverages in the world. Therefore, this study analyzed 49 coffee samples of Arabica and Robusta species of different geographical origins and the treatment of beans including three degrees of roasting with the use of LC-MS/MS. This is the first study to present a comprehensive analysis of Kopi Luwak coffee brew metabolites in comparison to fully washed coffees and the drying post-harvest treatment of Arabica or Robusta coffee brews. Kopi Luwak showed higher levels of caffeine and theophylline in comparison to the analyzed washed and unwashed Arabica coffees, as well as a different proportion of caffeoylquinic isomers. There was no difference between Kopi Luwak and other Arabica coffees in terms of the concentration of vitamin B3, amines, and phenolic acids. This was confirmed in PCA. The steaming and roasting of beans as well as the addition of black beans influence the concentration of 4-CQA and the nicotinic, ferulic, and quinic acids content.
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Azole fungicides: (Bio)degradation, transformation products and toxicity elucidation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149917. [PMID: 34525765 DOI: 10.1016/j.scitotenv.2021.149917] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/18/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
The increasing consumption of azole antifungal agents leads to their uncontrolled release into the environment. Therefore, it is crucial to remove their residues from natural ecosystems. This study aimed to examine the biological and chemical degradation of four typical azole fungicides: fluconazole (Fc), clotrimazole (Cl), climbazole (Cb), and epoxiconazole (Ep). The biodegradation was investigated using activated sludge and two novel Gram-negative bacterial strains. The chemical degradation experiments aimed to assess the efficiency of fungicides removal through UV treatment, the Fenton reaction, and a combination of these methods. Transformation products of Cb, Ep, and Cl photocatalytic removal were identified by mass spectrometry. In addition, the AlamarBlue® Assay and the MTT Assay allowed careful evaluation of the toxicity of azole derivatives and their transformation products towards newly isolated strains, Stenotrophomonas maltophilia AsPCl2.3 and Pseudomonas monteilii LB2. Among all azole fungicides, Cb was the most susceptible to biological removal while Fc, Ep, and Cl were basically resistant to biodegradation. Cl and Ep showed a significant biosorption on the activated sludge. Under optimized photolysis conditions, the removal efficiency of Cl, Cb, and Ep was significantly higher than that of biodegradation. The Fenton reaction supported by the UV-irradiation offered the best results of fungicides elimination. After 1 min of the experiment, Cl was almost completely removed while Cb and Ep removal rates reached an average of 60%. The proposed main degradation route of azole fungicides during UV-irradiation includes halogen atoms substitution by hydroxyl moieties. The final degradation product was imidazole or triazole. Azole fungicides and their transformation products differently affected the metabolic activity of Gram-negative bacteria. Cl and Cb intermediates showed lower toxicity than parent compounds. The findings help better understand the environmental impact of azole fungicides, their degradation, and toxicity. They also stress the need for reducing their uncontrolled release to the environment.
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Biodegradation and photo-Fenton degradation of bisphenol A, bisphenol S and fluconazole in water. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 289:117947. [PMID: 34391047 DOI: 10.1016/j.envpol.2021.117947] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Bisphenol A, bisphenol S, and fluconazole are ubiquitous environmental pollutants and their removal from water is of utmost importance. As the biodegradation of these compounds is usually not enough effective, often other degradation methods are required. The study presents the difference between biodegradation and photo-Fenton degradation with a much higher efficiency obtained in the latter process. Levels of biodegradation and chemical degradation were assessed based on high-performance liquid chromatography determination. Optimization of the photo-Fenton removal of bisphenol A, bisphenol S, and fluconazole resulted in about 100 % primary degradation of both bisphenols during 10-20 min and almost 90 % primary degradation of fluconazole within an hour. Degradation products formed in the process were identified using liquid chromatography with mass spectrometry and showed central scission of bisphenol S with the formation of phenol and sulfuric acid while for bisphenol A and fluconazole the oxidation resulted in much smaller structural changes.
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Occurrence and dietary risk of bisphenols and parabens in raw and processed cow's milk. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2021; 39:116-129. [PMID: 34702142 DOI: 10.1080/19440049.2021.1986234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Raw cow's milk collected from farmers and processed cow's milk purchased from local grocery stores were analysed for the presence of six bisphenols (bisphenol A, bisphenol S, bisphenol F, bisphenol AF, bisphenol B, and bisphenol E) and five parabens (methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben). The analytes were determined in their unconjugated form and (after enzymatic deconjugation) as the sum of conjugated and unconjugated compounds. The results show the presence of bisphenols mainly in the processed milk bought in stores while parabens were found in all samples of both raw and processed cow's milk. The average concentration of bisphenol A found in milk from cartons (0.87 ng mL-1) was greater than in milk from plastic bottles (0.35 ng mL-1). No such difference was found for parabens. Also, no considerable difference between the content of conjugated and total bisphenols and parabens was found except for ethylparaben. The determined compounds were always found below 2.0 ng mL-1 and calculations of the hazard quotients and the hazard index have shown that consumption of such milk is safe.
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Determination of bisphenols and parabens in breast milk and dietary risk assessment for Polish breastfed infants. J Food Compost Anal 2021. [DOI: 10.1016/j.jfca.2021.103839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Development of Poly(3,4-Ethylenedioxythiophene) (PEDOT) Electropolymerized Sorbent-Based Solid-Phase Microextraction (SPME) for the Determination of Parabens in Lake Waters by High-Performance Liquid Chromatography – Tandem Mass Spectrometry (HPLC-MS/MS). ANAL LETT 2021. [DOI: 10.1080/00032719.2020.1870232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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High-Performance Liquid Chromatography with Fluorescence Detection for the Determination of Capsaicin and Dihydrocapsaicin in Fat-Burning Dietary Supplements. ANAL LETT 2021. [DOI: 10.1080/00032719.2020.1839759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Application of the electropolymerized poly(3,4-ethylenedioxythiophene) sorbent for solid-phase microextraction of bisphenols. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:5068-5080. [PMID: 33034600 DOI: 10.1039/d0ay01118e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A new, simple, and effective procedure using poly(3,4-ethylenedioxythiophene)/lignosulfonate electropolymerized sorbent solid-phase microextraction (PEDOT/LS-SPME) combined with LC-MS/MS for determination of bisphenols in environmental water samples was developed. Various parameters influencing the performance of the analytical procedure including the type of sorbent, electropolymerization time, sorbent preconditioning time, extraction time, desorption (time and solvent), and sample pH were investigated and optimized. Under optimal conditions the proposed method allowed us to achieve good precision (n = 5) between 6.0 and 12.1%. The limits of detection were equal to 0.17 μg L-1 for BPA, 0.16 μg L-1 for BPF, 0.07 μg L-1 for BPE, 0.05 μg L-1 for BPB, and 0.027 μg L-1 for BPAF. The proposed method was successfully applied for the determination of bisphenols in aqueous environmental samples.
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The presence of bisphenol A in the thermal paper in the face of changing European regulations - A comparative global research. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114879. [PMID: 32505936 DOI: 10.1016/j.envpol.2020.114879] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/23/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
Bisphenol A (BPA) is used as a color developer in a thermal paper that after a heating process reacts with a leuco dye and changes it to a colored form. Receipts from cash registers are considered as the main source of consumer exposure to bisphenols together with polycarbonates and epoxy resins. Levels of BPA and its possible alternatives were determined in thermal paper samples collected between May 2018 and May 2019 in 22 European and 17 non-European countries on all inhabited continents (220 samples in total, 133 of which were from Europe and 87 from other countries). These measurements were intended to check the level of BPA presence in receipts originating from different countries, especially from Europe in the light of changing regulations restricting its use. The effect of thermal printing on developer content was also analyzed, but no major changes in concentrations of bisphenols were observed during the process. Thus, printed receipts could be used for the determination of bisphenol content. Analysis of receipts from 39 countries has shown that BPA is still the most common compound used around the world with 69% samples containing this color developer. Among other tested bisphenols, BPS was used as a color developer in 20% samples, but it was noted that all samples collected from Japan and the United States of America were found to contain only BPS. Other bisphenols (F, AF, E, and B) considered as possible alternatives for BPA were detected only at trace levels or not detected at all, which showed that they were not used as color developers. The relatively large use of BPS as a BPA substitute is worrying because this compound not only has similar endocrine properties but is also poorly biodegradable. Besides, its relatively high polarity facilitates spreading in the environment.
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Comparison of methylxantines, trigonelline, nicotinic acid and nicotinamide contents in brews of green and processed Arabica and Robusta coffee beans – Influence of steaming, decaffeination and roasting processes on coffee beans. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109344] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Removal of Bisphenol A and Its Potential Substitutes by Biodegradation. Appl Biochem Biotechnol 2020; 191:1100-1110. [PMID: 31960364 PMCID: PMC7320052 DOI: 10.1007/s12010-020-03247-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 01/08/2020] [Indexed: 01/16/2023]
Abstract
The possibility of removing bisphenol A and its five potential substitutes (bisphenols S, F, AF, E, and B) was tested using microorganism consortia from river water and activated sludge from municipal and rural wastewater treatment plants. For most bisphenols, biodegradation with activated sludge was faster than with river water and a greater extent of biodegradation was also achieved. However, only bisphenol A and bisphenol F underwent 100% primary biodegradation while other bisphenols degraded no more than about 50% which has some important implications in case of their increased usage. Metabolic activity in biodegradation liquors was also tested and it showed higher activity in the tests with activated sludge than with river water. However, there was no clear connection between the decline of metabolic activity and the extent of biodegradation as decreased activity was observed for two easily degrading bisphenols and two others with little biodegradability. It can be assumed that two different phenomena are involved in this process including depletion of nutrients for easily degradable bisphenol A and absence of nutrients for bacteria incapable of primary degradation of bisphenol AF and bisphenol S.
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Paper for Discussion: Cistus incanus a promising herbal tea rich in bioactive compounds: LC–MS/MS determination of catechins, flavonols, phenolic acids and alkaloids—A comparison with Camellia sinensis, Rooibos and Hoan Ngoc herbal tea. J Food Compost Anal 2019. [DOI: 10.1016/j.jfca.2019.01.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cistus incanus a promising herbal tea rich in bioactive compounds: LC–MS/MS determination of catechins, flavonols, phenolic acids and alkaloids—A comparison with Camellia sinensis, Rooibos and Hoan Ngoc herbal tea. J Food Compost Anal 2018. [DOI: 10.1016/j.jfca.2018.09.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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The effect of operational parameters on the biodegradation of bisphenols by Trametes versicolor laccase immobilized on Hippospongia communis spongin scaffolds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 615:784-795. [PMID: 28992503 DOI: 10.1016/j.scitotenv.2017.09.213] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/19/2017] [Accepted: 09/19/2017] [Indexed: 05/02/2023]
Abstract
Due to the rapid growth in quantities of phenolic compounds in wastewater, the development of efficient and environmentally friendly methods for their removal becomes a necessity. Thus, in a presented work, for the first time, a novel material, Hippospongia communis spongin-based scaffold, was used as a biopolymeric support for the immobilization of laccase from Trametes versicolor. The resulting biocatalytic systems were used for the biodegradation of three bisphenols: bisphenol A (BPA), bisphenol F (BPF) and bioremoval-resistant bisphenol S (BPS). Optimization of the immobilization and biodegradation methodologies was performed to increase bisphenols removal. The effect of temperature, pH and initial pollutant concentration was evaluated. It was shown that under optimal conditions, almost 100% of BPA (pH5, 30°C) and BPF (pH5, 40°C), and over 40% of BPS (pH4, 30°C) was removed from the solution at a concentration of 2mg/mL. Furthermore, the immobilized laccase exhibited good reusability and storage stability, retaining over 80% of its initial activity after 50days of storage. In addition, the main biodegradation products of BPA and BPF were identified. It was shown that mainly dimers and trimers were formed following the oxidation of bisphenols by the immobilized laccase.
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Detection of bisphenol A, cumylphenol and parabens in surface waters of Greater Poland Voivodeship. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 204:50-60. [PMID: 28854378 DOI: 10.1016/j.jenvman.2017.08.034] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/18/2017] [Accepted: 08/22/2017] [Indexed: 05/17/2023]
Abstract
Amounts of bisphenol A (BPA), 4-cumylphenol (CP) and 5 parabens - methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP) and benzylparaben (BzP) in Greater Poland Voivodeship's surface waters are reported. The water samples were collected from selected 15 locations in 2015-2016 at seven different time points: in March, June, August, and October 2015 and March, June, and September 2016. MP was found in every tested sample with typical concentration at several dozen nanograms per liter and the highest level almost 1600 ng L-1 in a sample collected from the Warta River in October 2015. The other four parabens were determined at considerably lower concentrations than MP at levels not exceeding 100 ng L-1 with PP found at the highest and BzP at the lowest levels. BPA was determined at similar concentration level to parabens - between 5 ng L-1 and 95 ng L-1 and CP was found only in a limited number of samples. Noticeable seasonal changes of paraben concentrations were found showing that for these compounds the pollutant release factor dominates both the biodegradation factor and the water volume factor. These seasonal changes were not observed for BPA and CP. Out of all determined parabens only MP was found at considerably higher concentrations than BPA. However, MP's endocrine properties are much lower than those of BPA posing a lower environmental impact potential than BPA. Influence of other (more endocrine disrupting) parabens is also relatively weak in comparison to BPA due to their considerably lower concentrations in the environment.
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Canadian Spine Society abstracts1.1.01 Supraspinal modulation of gait abnormalities associated with noncompressive radiculopathy may be mediated by altered neurotransmitter sensitivity1.1.02 Neuroprotective effects of the sodium-glutamate blocker riluzole in the setting of experimental chronic spondylotic myelopathy1.1.03 The effect of timing to decompression in cauda equina syndrome using a rat model1.2.04 Intraoperative waste in spine surgery: incidence, cost and effectiveness of an educational program1.2.05 Looking beyond the clinical box: the health services impact of surgical adverse events1.2.06 Brace versus no brace for the treatment of thoracolumbar burst fractures without neurologic injury: a multicentre prospective randomized controlled trial1.2.07 Adverse event rates in surgically treated spine injuries without neurologic deficit1.2.08 Functional and quality of life outcomes in geriatric patients with type II odontoid fracture: 1-year results from the AOSpine North America Multi-Center Prospective GOF Study1.3.09 National US practices in pediatric spinal fusion: in-hospital complications, length of stay, mortality, costs and BMP utilization1.3.10 Current trends in the surgical treatment of adolescent idiopathic scoliosis in Canada1.3.11 Sagittal spinopelvic parameters help predict the risk of proximal junctional kyphosis for children treated with posterior distraction-based implants1.4.12 Correlations between changes in surface topography and changes in radiograph measurements from before to 6 months after surgery in adolescents with idiopathic scoliosis1.4.13 High upper instrumented vertebra (UIV) sagittal angle is associated with UIV fracture in adult deformity corrections1.4.14 Correction of adult idiopathic scoliosis using intraoperative skeletal traction1.5.01 Cauda equina: using management protocols to reduce delays in diagnosis1.5.02 Predicting the need for tracheostomy in patients with acute traumatic spinal cord injury1.5.03 A novel animal model of cervical spondylotic myelopathy: an opportunity to identify new therapeutic targets1.5.04 A review of preference-based measures of health-related quality of life in spinal cord injury research1.5.05 Predicting postoperative neuropathic pain following surgery involving nerve root manipulation based on intraoperative electromyographic activity1.5.06 Detecting positional injuries in prone spinal surgery1.5.07 Percutaneous thoracolumbar stabilization for trauma: surgical morbidity, clinical outcomes and revision surgery1.5.08 Systemic inflammatory response syndrome in spinal cord injury patients: Does its presence at admission affect patient outcomes?2.1.15 One hundred years of spine surgery — a review of the evolution of our craft and practice in the spine surgical century [presentation]2.1.16 Prevalence of preoperative MRI findings of adjacent segment disc degeneration in patients undergoing anterior cervical discectomy and fusion2.1.17 Adverse event rates of surgically treated cervical spondylopathic myelopathy2.1.18 Morphometricand dynamic changes in the cervical spine following anterior cervical discectomy and fusion and cervical disc arthroplasty2.1.19 Is surgery for cervical spondylotic myelopathy cost-effective? A cost–utility analysis based on data from the AO Spine North American Prospective Multicentre CSM Study2.2.20 Cost–utility of lumbar decompression with or without fusion for patients with symptomatic degenerative lumbar spondylolisthesis (DLS)2.2.21 Minimally invasive surgery lumbar fusion for low-grade isthmic and degenerative spondylolisthesis: 2- to 5-year follow-up2.2.22 Results and complications of posterior-only reduction and fusion for high-grade spondylolisthesis2.3.23 Fusion versus no fusion in patients with central lumbar spinal stenosis and foraminal stenosis undergoing decompression surgery: comparison of outcomes at baseline and follow-up2.3.24 Two-year results of interspinous spacers (DIAM) as an alternative to arthrodesis for lumbar degenerative disorders2.3.25 Treatment of herniated lumbar disc by sequestrectomy or conventional discectomy2.4.26 No sustained benefit of continuous epidural analgesia for minimally invasive lumbar fusion: a randomized double-blinded placebo controlled study2.4.27 Evidence and current practice in the radiologic assessment of lumbar spine fusion2.4.28 Wiltse versus midline approach for decompression and fusion of the lumbar spine2.5.09 The effect of soft tissue restraints following type II odontoid fractures in the elderly — a biomechanical study2.5.10 Development of an international spinal cord injury (SCI) spinal column injury basic data set2.5.11 Evaluation of instrumentation techniques for a unilateral facet perch and fracture using a validated soft tissue injury model2.5.12 Decreasing neurologic consequences in patients with spinal infection: the testing of a novel diagnostic guideline2.5.13 Prospective analysis of adverse events in surgical treatment of degenerative spondylolisthesis2.5.14 Load transfer characteristics between posterior fusion devices and the lumbar spine under anterior shear loading: an in vitro investigation2.5.15 Preoperative predictive clinical and radiographic factors influencing functional outcome after lumbar discectomy2.5.16 A Thoracolumbar Injury Classification and Severity Score (TLICS) of 4: What should we really do?3.1.29 Adverse events in emergent oncologic spine surgery: a prospective analysis3.1.30 En-bloc resection of primary spinal and paraspinal tumours with critical vascular involvement3.1.31 The treatment impact of minocycline on quantitative MRI in acute spinal cord injury3.1.32 Benefit of minocycline in spinal cord injury — results of a double-blind randomized placebo-controlled study3.2.33 Improvement of magnetic resonance imaging correlation with unilateral motor or sensory deficits using diffusion tensor imaging3.2.34 Comparing care delivery for acute traumatic spinal cord injury in 2 Canadian centres: How do the processes of care differ?3.2.35 Improving access to early surgery: a comparison of 2 centres3.3.36 The effects of early surgical decompression on motor recovery after traumatic spinal cord injury: results of a Canadian multicentre study3.3.37 A clinical prediction model for long-term functional outcome after traumatic spinal cord injury based on acute clinical and imaging factors3.3.38 Effect of motor score on adverse events and quality of life in patients with traumatic spinal cord injury3.4.39 The impact of facet dislocation on neurologic recovery after cervical spinal cord injury: an analysis of data on 325 patients from the Surgical Trial in Acute Spinal Cord Injury Study (STASCIS)3.4.40 Toward a more precise understanding of the epidemiology of traumatic spinal cord injury in Canada3.4.41 Access to care (ACT) for traumatic SCI: a survey of acute Canadian spine centres3.4.42 Use of the Spine Adverse Events Severity (SAVES) instrument for traumatic spinal cord injury3.5.17 Does the type of distraction-based growing system for early onset scoliosis affect postoperative sagittal alignment?3.5.18 Comparison of radiation exposure during thoracolumbar fusion using fluoroscopic guidance versus anatomic placement of pedicle screws3.5.19 Skeletal traction for intraoperative reduction in adolescent idiopathic scoliosis3.5.20 Utility of intraoperative cone-beam computed tomography (O-ARM) and stereotactic navigation in acute spinal trauma surgery3.5.21 Use of a central compression rod to reduce thoracic level spinal osteotomies3.5.22 ICD-10 coding accuracy for spinal cord injured patients3.5.23 Feasibility of patient recruitment in acute SCI trials3.5.24 Treatment of adult degenerative scoliosis with DLIF approaches. Can J Surg 2012. [DOI: 10.1503/cjs.012212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Spectral density matrix of a single photon measured. PHYSICAL REVIEW LETTERS 2007; 99:123601. [PMID: 17930501 DOI: 10.1103/physrevlett.99.123601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Indexed: 05/25/2023]
Abstract
We propose and demonstrate a method for measuring the spectral density matrix of a single photon pulse. The method is based on registering Hong-Ou-Mandel interference between a photon to be measured and a pair of attenuated and suitably delayed laser pulses described by a known spectral amplitude. The density matrix is retrieved from a two-dimensional interferogram of coincidence counts. The method has been implemented for a type-I down-conversion source, pumped by ultrashort laser pulses. The experimental results agree well with a theoretical model which takes into account the temporal as well as spatial effects in the source.
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The development and validation of a dysphagia-specific quality-of-life questionnaire for patients with head and neck cancer: the M. D. Anderson dysphagia inventory. ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 2001; 127:870-6. [PMID: 11448365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
OBJECTIVE To design a reliable and validated self-administered questionnaire whose purpose is to assess dysphagia's effects on the quality of life (QOL) of patients with head and neck cancer. DESIGN Cross-sectional survey study. METHODS Focus groups were convened for questionnaire development and design. The M. D. Anderson Dysphagia Inventory (MDADI) included global, emotional, functional, and physical subscales. One hundred consecutive adult patients with a neoplasm of the upper aerodigestive tract who underwent evaluation by our Speech Pathology team completed the MDADI and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Speech pathologists completed the Performance Status Scale for each patient. Validity and reliability properties were calculated. Analysis of variance was used to assess how well the MDADI discriminated between groups of patients. RESULTS The internal consistency reliability of the MDADI was calculated using the Cronbach alpha coefficient. The Cronbach alpha coefficients of the MDADI subscales ranged from 0.85 to 0.93. Test-retest reliability coefficients of the subscales ranged from 0.69 to 0.88. Spearman correlation coefficients between the MDADI subscales and the SF-36 subscales demonstrated construct validity. Patients with primary tumors of the oral cavity and oropharynx had significantly greater swallowing disability with an adverse impact on their QOL compared with patients with primary tumors of the larynx and hypopharynx (P<.001). Patients with a malignant lesion also had significantly greater disability than patients with a benign lesion (P<.001). CONCLUSIONS The MDADI is the first validated and reliable self-administered questionnaire designed specifically for evaluating the impact of dysphagia on the QOL of patients with head and neck cancer. Standardized questionnaires that measure patients' QOL offer a means for demonstrating treatment impact and improving medical care. The development and validation of the MDADI and its use in prospective clinical trials allow for better understanding of the impact of treatment of head and neck cancer on swallowing and of swallowing difficulty on patients' QOL.
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Assigning time-linked exposure status to controls in unmatched case-control studies: alcohol use and nearly lethal suicide attempts. Stat Med 2001; 20:1479-85. [PMID: 11343368 DOI: 10.1002/sim.684] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In case-control studies, determination of alcohol consumption by cases immediately prior to the injury event is often conceptually straightforward. However, determination of consumption status by controls is difficult because they lack a reference point, especially when cases and controls are not individually matched. We describe a method of assigning alcohol consumption status to controls using a 24-hour drinking history, the distribution in time of case events, and the random assignment of a specific time period to each control subject. This methodology offers a practical approach for determining alcohol consumption status among control subjects immediately prior to a case event, when controls lack a reference point and have not been individually matched to cases. Published in 2001 by John Wiley & Sons, Ltd.
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The synthesis and structure of the derivatives of 2-deoxy-2-hydroxyimino-D-lyxo-hexopyranosyl-L-cysteine and -thiophenol. Carbohydr Res 2000; 326:151-8. [PMID: 10877098 DOI: 10.1016/s0008-6215(00)00035-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
3,4,6-Tri-O-acetyl-2-deoxy-2-hydroxyimino-beta and -alpha-D-lyxo-hexopyranosides of thiophenol (3, 4) and the methyl ester of N-benzoyl-L-cysteine have been synthesised by condensation of 3,4,6-tri-O-acetyl-2-deoxy-2-nitroso-alpha-D-galactopyranosyl chloride with thiophenol and the L-cysteine derivative, respectively. The conformation of the sugar residue and configuration of the anomeric centre as well as of the hydroxyimino group were established on the basis of the 1H NMR (DQF-COSY, ROESY, TOCSY) spectrometric techniques and polarimetric data. Additionally, the structure of S-[3,4,6-tri-O-acetyl-2-deoxy-2-(Z)-hydroxyimino-beta-D-lyxo -hexopyranosyl]-thiophenol (3) was supported by X-ray diffraction data.
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Outcome evaluation of a multi-component violence-prevention program for middle schools: the Students for Peace project. HEALTH EDUCATION RESEARCH 2000; 15:45-58. [PMID: 10788201 DOI: 10.1093/her/15.1.45] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study evaluated the effect of Students for Peace, a multi-component violence-prevention intervention, on reducing aggressive behaviors among students of eight middle schools randomly assigned into intervention or control conditions. The intervention, based on Social Cognitive Theory, included the formation of a School Health Promotion Council, training of peer mediators and peer helpers, training of teachers in conflict resolution, a violence-prevention curriculum, and newsletters for parents. All students were evaluated in the spring of 1994, 1995 and 1996 (approximately 9000 students per evaluation). Sixth graders in 1994 were followed through seventh grade in 1995 or eighth grade in 1996 or both (n = 2246). Cohort and cross-sectional evaluations indicated little to no intervention effect in reducing aggressive behaviors, fights at school, injuries due to fighting, missing classes because of feeling unsafe at school or being threatened to be hurt. For all variables, the strongest predictors of violence in eighth grade were violence in sixth grade and low academic performance. Although ideal and frequently recommended, the holistic approach to prevention in schools in which teachers, administrators and staff model peaceful conflict resolution is difficult to implement, and, in this case, proved ineffective. The Students for Peace experience suggests that interventions begin prior to middle school, explore social environmental intervention strategies, and involve parents and community members.
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Padres Trabajando por la Paz: a randomized trial of a parent education intervention to prevent violence among middle school children. HEALTH EDUCATION RESEARCH 1999; 14:421-426. [PMID: 10539232 DOI: 10.1093/her/14.3.421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper reports the results of a randomized trial to test the effectiveness of a theoretically derived intervention designed to increase parental monitoring among Hispanic parents of middle school students. Role model story newsletters developed through the process of Intervention Mapping were mailed to half of a subsample of parents whose children participated in Students for Peace, a comprehensive violence prevention program. The results indicated that parents in the experimental condition (N = 38) who had lower social norms for monitoring at baseline reported higher norms after the intervention than the parents in the control condition (N = 39) (P = 0.009). Children of parents in the experimental group reported slightly higher levels of monitoring at follow-up across baseline values, whereas control children who reported moderate to high levels of monitoring at pre-test reported lower levels at follow-up (P = 0.04). These newsletters are a population-based strategy for intervention with parents that show some promise for comprehensive school-based interventions for youth.
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Abstract
The cancer risk model described herein first appeared in 1982. The model provides a plausible mechanism with biological underpinnings that might reasonably explain observed phenomena in cancer dose-response studies that are not being addressed by the risk models currently in use. This article is a summary and explanation of the features of the model that relate to hormesis. Data from several saccharin studies served in large part to motivate the original research, and were used to illustrate beneficial low-dose effects that could be explained by the model. The model itself is a function of linear ratios of the administered dose x. Linear ratios arise naturally from non-linear Michaelis-Menten kinetics, as described in the next section. The one-hit cancer risk model is used to illustrate the hormetic concepts brought out by linear ratios. The one-hit model is modified to account for repair and for non-linear kinetics, by using a linear ratio of the administered dose instead of the actual administered dose, and by expressing the probability that a 'hit' is repaired as a linear ratio of the administered dose. The phenomenon of hormesis - or low-dose beneficial effects-has been widely observed and accepted. Yet none of the cancer risk models currently in wide use have attempted to accommodate hormetic effects. The modified one-hit model developed herein does not attempt to account for elimination or detoxification, but nevertheless it provides plausible explanations for certain classes of observed hormetic phenomena associated with experimental testing of carcinogenic substances in animals.
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Comments on: Mechanistic model predicts a U-shaped relation of radon exposure to lung cancer risk reflected in combined occupational and US residential data (by KT Bogen). Hum Exp Toxicol 1998. [DOI: 10.1191/096032798678908260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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A cancer risk model with adaptive repair. Hum Exp Toxicol 1998. [DOI: 10.1191/096032798678908279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Comments on: Mechanistic modeling of rodent liver tumor promotion at low levels of exposure: an example related to dose-response relationships for 2,3,7,8-tetra-chlorodibenzo-p-dioxin (by Andersen ME and Conolly RB). Hum Exp Toxicol 1998. [DOI: 10.1191/096032798678908251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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The students for peace project: a comprehensive violence-prevention program for middle school students. Am J Prev Med 1996; 12:22-30. [PMID: 8909621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Students for Peace is a three-year project (October 1993- September 1996) designed to evaluate a comprehensive, school-based intervention that seeks to prevent violence among sixth-, seventh-, and eighth-grade students in a large urban school district in Texas. This study examines the hypothesis that students exposed to a two-year multiple-component intervention will reduce aggressive behavior compared to students who receive the district's "usual care" of violence prevention activities. Students for Peace is based largely on Social Learning. Theory (SLT), which addresses both the psychosocial dynamics underlying health behavior and the methods of promoting behavior change, while emphasizing cognitive processes and their effect on behavior. SLT explains human behavior in terms of a model in which three factors-behavior, social-environmental influences, and personal factors (such as personality, perceptions and expectations, and affect)-all interact. Theoretically, an individual's behavior is uniquely determined by a combination of these factors; thus, these factors become the elements for intervention strategies. The intervention program includes four main components: (1) modification of the school environment, (2) a violence-prevention curriculum, (3) peer leadership, and (4) parent education. Students for Peace is using a nested cross-sectional and cohort design in which school is the unit of design, allocation, and analysis. Eight schools, four intervention and four control, are participating. In May 1994, a questionnaire was administered to all students in school the day of the survey. A posttest evaluation was taken in the spring of 1995 and will be followed by a final posttest in spring 1996. A total of 8,865 students responded to the baseline survey. Nearly all variables indicated comparability between treatment and control conditions. As a population, Students for Peace participants are largely Hispanic (65%) or African American (19%). Violence-related variables indicated 30-day fighting prevalence, 23%; 12-month prevalence of injuries due to fighting, 14%; 30-day hand-gun carrying prevalence, 11%; 30-day prevalence of taunts and threats at school, 27%, and threats going to and from school, 26%. Overall, the data from Year 1 activities indicate a population in need of violence-prevention intervention. The challenge is to mold existing district resources into a theoretically sound program of interventions. If that program is found effective, the district will already have the necessary documentation, personnel, and skills for broader dissemination.
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Abstract
PURPOSE To evaluate the effect of a violence prevention curriculum and of trained peer leaders on self-reported aggressive behaviors, knowledge about violence and conflict-resolution skills, self-efficacy, and attitudes among 223 6th graders. METHODS The effect of two intervention groups (violence prevention curriculum taught by the teacher with or without the assistance of trained peer leaders) and one control group were compared. Ten 6th grade classes (four control and six intervention classes) of four middle schools participated in the study. Students were evaluated before and shortly after the implementation of the curriculum, as well as 3 months later. RESULTS The intervention reduced self-reported aggressive behaviors among boys, but this reduction was significant only in two of the six intervention classes. Both interventions had an overall significant effect on increasing knowledge about violence and skills to reduce violence. After the intervention, students also developed a more negative attitude toward responding violently when provoked. Attitude change was stronger among students from the teacher plus peer leader group. No intervention effect was observed on self-efficacy nor on attitudes toward skills to reduce violence. Changes were not maintained over time. CONCLUSIONS Results emphasize the need for continuous and comprehensive interventions, follow-up evaluations, and careful selection of peer leaders. Aggressive behaviors, not knowledge alone, should be used as the main dependent variable.
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Abstract
The hypothesis that introduction of a defined policy of managing labor in nulliparas, active management of labor, would reduce the incidence of cesarean section (CS) for dystocia was examined by the introduction of active management at Hermann Hospital, the University of Texas affiliated hospital in Houston. The study was conducted over four consecutive 6-month periods. Observational data were accumulated for the year preceding introduction of active management, which served as the control period. The overall incidence of CS in nulliparas in the two control periods was 23 and 25%, and declined significantly to 20 and 17.7% in the intervention periods. The incidence of CS for dystocia fell significantly from 13 and 15% to 10 and 8.1%, whereas the incidence for other indications was unchanged. There were no significant differences in perinatal outcome judged by incidence of fetal death in labor, neonatal death associated with asphyxia, rate of admission to neonatal care with a diagnosis of asphyxia, or incidence of neonatal seizure. The data suggest that active management of labor reduces the incidence of cesarean section significantly and that these results can be achieved without detriment to mother or child.
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A cluster classification for histologic diagnoses of CNS tumors in an epidemiologic study. Neuroepidemiology 1990; 9:2-16. [PMID: 2330068 DOI: 10.1159/000110747] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This paper introduces a method which was utilized to sort multiple pathologic diagnoses pertaining to brain tumors into clusters of equivalent diagnostic terms for an epidemiological study of brain cancer. The method enabled the medical record abstractors to ascertain cases for the study. It enabled the reviewing pathologist to identify differences between original and reviewed diagnoses. It identified the large range of classification systems of brain tumors used by practicing pathologists as a factor contributing to confusion of data if slide reviews are not incorporated into epidemiological studies, and demonstrated how the use of a cluster classification alleviates this problem.
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Abstract
Data were obtained prospectively for 7,912 head-injured patients admitted from 1980 to 1981 to 41 hospitals in 3 U.S. metropolitan areas. Highly significant independent predictors of mortality were motor score, number of reactive eyes, systolic blood pressure, abdominal injury, chest injury, age, and hospital unit (hospital or group of hospitals). The difference between the number of deaths observed and the number expected, by hospital unit, ranged from 43% below expectation to 52% above expectation. The 2 hospital units with the lowest mortality had only 1 death, where 9.4 would be expected, in patients whose risk of death was estimated to be less than 10%. In the single hospital with clearly excess mortality, however, the standardized mortality ratios were 208, 135, and 144% for the risk groups whose probabilities of death were 0 to 50, 50 to 80, and 80 to 100%, respectively. The lack of deaths in those hospitals with the best mortality experience and the excess mortality in the hospital with the worst mortality experience appear to be explained largely by differences in patients who, by clinical criteria, seem to be at low risk for death, and not by severely injured patients.
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