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Honeybees and hive products could be used as bioindicators of pesticide exposure in surrounding areas, but the associations have rarely been examined. We collected samples of bees, hive products and environmental dust from 12 apiaries during the blooming season in eastern Taiwan and assessed the relationships between pesticides in apiarian samples and the environment. Samples were analyzed for 14 pesticides using gas or liquid chromatography coupled with mass spectrometry. Sick bees, dead bees, bee pollen, beeswax and environmental dust in the outer rings (>150 m) surrounding the apiaries were contaminated with high levels of pesticides (mean concentration: >270 ng/g in total). In terms of concentrations of all pesticides, insecticides, herbicides and fungicides, most apiarian sample matrices were significantly correlated with environmental dust within a range of 2.5 km (ρ > 0.6, p < 0.05), suggesting their potential as bioindicators. Of those apiarian matrices with high contamination contents, dead bees or beeswax may be a good bioindicator for all pesticides but not for herbicides, because of the insignificant correlation with environmental dust (ρ < 0.5). For all types of pesticides, we recommend sick bees and bee pollen as choices for bioindicators, because of their high contamination levels for detection and complete representativeness of the environment.
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While pollinating, honeybees are subject to exposure to a variety of pesticides; with their characteristics of certain foraging distances, they could serve as bioindicators of pesticide exposure in a neighborhood. We conducted a study to assess availability by collecting and analyzing bee samples from 15 apiaries located in East Taiwan and dust samples from the adjacent environment, and by finding relations between both samples. Seventeen pesticides were selected for the analysis using gas or liquid chromatography coupled with mass spectrometry, and eight (three insecticides, two herbicides, and three fungicides) were more frequently detected from bee or dust samples; the levels of these pesticides were mostly under 1000 ng/g. Significant correlation results (r â 0.8) between residue concentrations in bees and in dust suggest that honeybees could be a good bioindicator for exposure to herbicides and fungicides within certain ranges. The pesticide contents of sick/dead bees were much higher than those of healthy counterparts regarding any pesticide type, with the mean total concentrations of 635 ng/g and 176 ng/g, respectively. We conclude that honeybees could be used as bioindicators of pesticide exposure; sick/dead bees could serve as a warning sign of the severity of pesticide pollution.
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Resource recycling has become an integral part of environmental protection efforts. At present, the development of Taiwan's resource recovery and related works are quite mature. However, laborers or volunteers working in resource recycling stations may be exposed to different types of hazards during the recycling process. These hazards can be divided into biological, chemical, and musculoskeletal problems. These hazards are usually related to the work environment and work habits; therefore, a related control strategy is needed. Tzu Chi's recycling business has been running for over 30 years. In addition to leading the trend of resource recycling in Taiwan, many elderly people have also participated in Tzu Chi recycling stations as volunteers. These older volunteers may be more sensitive to exposure to hazards, and thus the focus of this review is to illustrate the possible hazards and health impacts of resource recovery work and to recommend relevant interventions to improve occupational health during resource recovery work.
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Pesticides are widely used globally. Due to their widespread use, exposure to pesticides is of concern. In addition to occupational exposure, residential exposure during pesticide application is a concern for those living in or near agricultural areas. The objective of this study was to analyze the association between residential proximity to agricultural pesticide use and birth outcomes. The association between residential proximity to agricultural land use as pesticide exposure and birth outcomes was explored in a birth cohort including 283 pregnant women from a medical center in Hualien during 2013-2016. In the third trimester, we collected demographic information and the residential addresses of pregnant women via structured questionnaires. After delivery, newborn birth weight, gestational age, and head circumference were collected from medical records. Maternal residential address during pregnancy was collected for geospatial mapping. The percentages of farmland area within circular buffers of different sizes were applied to estimate pesticide exposure. Associations between residential proximity to agricultural land use as pesticide exposure and birth outcomes were analyzed by multiple linear regression analyses. A significantly smaller head circumference was associated with agricultural farmland located within 400 m (ß = - 0.51 [95% CI, - 0.99, - 0.03], P = 0.037) and 500 m (ß = - 0.67 [95% CI, - 1.14, - 0.19], P = 0.006) radii of residences in the tertile 2 group. A significantly smaller head circumference was also associated with dry farming area within 400 m (ß = - 0.70 [95% CI, - 1.17, - 0.24], P = 0.003) and 500 m (ß = - 0.81 [95% CI, - 1.27, - 0.34], P = 0.001) radii of residences in the tertile 2 group. The multivariate linear regression analyses did not show any significant association between residential farmland area and birth weight or gestational age. In conclusion, residential proximity to agricultural land use as pesticide exposure was associated with negative infant birth outcomes, especially a small head circumference. In the future, agricultural land use information could be combined with biological samples to more accurately assess exposure in pregnant women.
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Praguicidas , Recém-Nascido , Lactente , Humanos , Feminino , Gravidez , Praguicidas/análise , Peso ao Nascer , Exposição Materna , Agricultura , Idade Gestacional , Exposição Ambiental/análiseRESUMO
Pesticide drift was reported in many international studies, but rarely studied in Taiwan. We conducted a study in a rural region of Taiwan to examine the associations between pesticides in house dust and nearby agricultural areas using geographic information system (GIS). A questionnaire regarding home characteristics and pesticide use, and indoor and outdoor dust samples were collected from 47 rural homes. Dust samples were analyzed for six pesticides, and agricultural land data for GIS analysis were retrieved from a national website. All but prallethrin were frequently detected from indoor dust samples (>50%), and the maximum concentrations were all below 1000 ng/g. Detection frequencies and concentrations of pesticides in outdoor dust samples were even lower than that in indoor dust samples. Only "work involving pesticides" in the questionnaire was significantly associated with four pesticides in house dust (p < 0.05). Carbofuran and tetramethrin in house dust were significantly correlated with rice cultivation area at certain buffer distances (ρ > 0.33, p < 0.05), and chlorpyrifos was found to be associated with abandoned cultivation area, suggesting the occurrence of pesticide drift. Despite the low levels of pesticides in house dust, residents in the rural region should be cautious of pesticide drift from nearby active or abandoned farmlands.
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Phthalic acid esters (PAEs) commonly used as plasticizers are distributed ubiquitously in the living environment. We conducted a field study to examine the associations between PAE residue in dust and home characteristics/living habits in 47 rural homes in Taiwan. A questionnaire regarding home characteristics/living habits and composite sampling of house dust were conducted in each participating home. Five PAEs were selected for analysis on gas chromatography-mass spectrometry with the limits of quantification being 0.5 ng/g or lower. Uni- and multivariate linear regression analyses were performed for examining the associations. The five PAEs were prevalently detected from the samples, and the concentrations were below 1000 ng/g; di(2-ethylhexyl) phthalate (DEHP) was the most frequently detected PAE (85%), whereas di-isobutyl phthalate (DiBP) appeared to the most abundant congener with the maximum concentration of 807.65 ng/g. Floor cleaning frequency and use of detergents for floor cleaning were significantly associated with DEHP in dust (P < 0.05), suggesting additives of plasticizers in detergent products. The factors of plastic wraps in storage and use of disposable cups were both significantly related to DiBP (P < 0.01), which could be extensively used in food packaging products. We confirmed that several home characteristics/living habits were related to certain PAE residue in dust.
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Poeira , Ácidos Ftálicos , China , Poeira/análise , Ésteres/análise , Hábitos , Ácidos Ftálicos/análise , TaiwanRESUMO
We conducted a pilot study to examine the relationship between organophosphate (OP) and pyrethroid (PYR) insecticides in blood and their metabolites in urine. A total of 30 pregnant women were enrolled in the study, and blood and urine was sampled from each subject during a regular clinic visit. Two OP and nine PYR insecticides were selected for blood sample analysis, while six OP and five PYR metabolites were analyzed for urine specimens. Both types of samples were processed and analyzed on gas chromatography-mass spectrometry. For OPs in blood, chlorpyrifos had a higher mean concentration (73.33 µg/L) than terbufos. For PYRs in blood, cypermethrin and imiprothrin were the most frequently detected species with the highest mean concentrations (151.25 and 141.25 µg/L). The concentrations of PYRs appeared to be higher than that of OPs, and the most frequently detected PYRs were commonly used in domestic products, suggesting that the exposure could mostly originate from use of domestic insecticides. The correlation between insecticides in blood and their metabolites in urine was significantly high (r = 0.795 for OPs and 0.882 for PYRs, p < 0.001), indicating routine exposure at a steady state. Residents should be cautious with domestic use of insecticide products to lower their exposure.
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Poluentes Ambientais/metabolismo , Inseticidas/metabolismo , Exposição Materna/estatística & dados numéricos , Organofosfatos/metabolismo , Gravidez/metabolismo , Piretrinas/metabolismo , Adulto , Biomarcadores/sangue , Biomarcadores/urina , Monitoramento Ambiental , Feminino , Humanos , Projetos Piloto , TaiwanRESUMO
Dry eye disease (DED) has become a common eye disease in recent years and appears to be influenced by environmental factors. This study aimed to examine the association between the first occurrence of DED, air pollution and weather changes in Taiwan. We used the systematic sampling cohort database containing 1,000,000 insureds of the National Health Insurance of Taiwan from 2004 to 2013, and identified a total of 25,818 eligible DED subjects. Environmental data, including those of air pollutants, temperature and relative humidity, were retrieved from the environmental monitoring stations adjacent to subjects' locations of clinics as exposure information. We applied the case-crossover design, which used the same subjects experiencing exposures on diagnosis days as cases and those on other days as controls. The descriptive statistics showed that the first occurrences of DED were the most for the elderly by age (53.6%), women by gender (68.9%), and spring by season (25.9%). Multivariate conditional logistic regression analyses indicated that carbon monoxide (CO), nitrogen dioxide (NO2), and temperature were positively associated with DED (p < 0.05), while relative humidity was negatively related (p < 0.001). Because CO and NO2 together are considered a surrogate of traffic emission, which is easier to control than the uprising temperature, it is suggested that efficient management and control of traffic emission may lower the probability of DED occurrence.
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Poluentes Atmosféricos/análise , Poluição do Ar/análise , Síndromes do Olho Seco/epidemiologia , Exposição Ambiental , Tempo (Meteorologia) , Adolescente , Adulto , Fatores Etários , Idoso , Síndromes do Olho Seco/induzido quimicamente , Monitoramento Ambiental , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prevalência , Estações do Ano , Fatores Sexuais , Taiwan/epidemiologia , Adulto JovemRESUMO
A quick and cost-effective method to analyze leafy vegetable nitrate on spectrometry was developed and compared with a standard method using high performance liquid chromatography (HPLC). This method was designed to use ion-exchange solid phase extraction (SPE) cartridges in reducing interference from organic matrices to meet the criterion of an existing method for analyzing nitrate in wastewater. Nine vegetables (bok coy, cabbage, celery, Chinese cabbage, Chinese kale, lettuce, mustard green, pak choi, and water spinach) were selected for the method testing with three replicates being conducted for each vegetable. The nitrate contents ranged from 800 to 4,300 µg/g, with bok coy, celery, and pak choi being the highest. Data derived from spectrometry and HPLC were close to each other with most relative errors being within ±10% and were highly correlated with an R square value of 0.969. Stability testing and spike analysis resulted in a mean coefficient of variation lower than 6% and a mean recovery rate of 83.7%, suggesting reliability of the method. In addition, both the cost and time consumption for using this method were lower than the standard method using HPLC or ion chromatography, making this spectrometric method a good alternative for analysis of leafy vegetable nitrate.
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INTRODUCTION: Stoneworkers in Taiwan are exposed to occupational noise and suffer hearing impairment. A complete assessment of exposure and health effects is needed for a better understanding. MATERIALS AND METHODS: We accessed nine stone factories, monitored the environmental and personal doses of noise, analyzed the frequency spectra of noise from various machines, and recruited 55 stoneworkers and 25 administrative staff as controls for pure tone audiometry testing. RESULTS: The means (standard deviations) of 8-h time-weighted averages for environmental and personal monitoring were 85.0 (6.2) and 87.0 (5.5) dB(A), respectively, with seven of nine personal measurements being higher than the respective environmental results. The monitoring data suggest that occupational noise in the stonework environments should be a matter of great concern. Nearly all frequency spectra indicated peak values occurring between 2 and 4 kHz, which were within the bands for early noise-induced hearing loss (NIHL). The mean hearing threshold levels of the study participants were elevated in low and high frequencies (29.2 and 41.2 dB) compared to that of controls (â¼25 dB for both bands). Linear regression analysis indicated no significance in the low frequencies (P = 0.207) but statistical significance in the high frequencies (P = 0.002) after adjustment for covariates, suggesting NIHL among the stoneworkers. CONCLUSION: Stoneworkers apparently display early signs of NIHL. Noises in the stonework factories with peaks in the high frequencies are harmful to hearing ability. Employers and workers have to comply with the regulation strictly to prevent further hearing damage.
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Indústrias Extrativas e de Processamento , Perda Auditiva Provocada por Ruído/epidemiologia , Ruído Ocupacional/efeitos adversos , Doenças Profissionais/epidemiologia , Exposição Ocupacional/análise , Adulto , Audiometria de Tons Puros , Limiar Auditivo , Monitoramento Ambiental , Perda Auditiva Provocada por Ruído/etiologia , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Taiwan/epidemiologiaRESUMO
We conducted a pilot study to examine pesticides in dust of homes in a rural county of Taiwan. A total of 56 homes of pregnant women were included in the study. Indoor and outdoor dust was collected by a vacuum sampler and a dustpan/brush set, respectively. Nine pesticides were selected for analysis on gas chromatography-mass spectrometry with the detection limits being 0.088 ng/g or lower. The most detected pesticides were cypermethrin and chlorpyrifos, which appeared in 82.7 and 78.8% of indoor samples and 48.2 and 39.3% of outdoor samples, respectively. The detection of pesticides from indoor and outdoor dust, however, was not consistent, indicating different sources of pesticides. In addition to those two most detected, permethrin, prallethrin, and tetramethrin, which were common ingredients of insecticide products for indoor use, were also frequently found in indoor dust, suggesting that indoor use of such pesticide products may have been a major source. Fewer pesticides were found in outdoor dust, but the outdoor detection of chlorpyrifos was significantly associated with farms present inside the circles with radii of 50 and 100 m surrounding the homes (P = 0.021, 0.016). It is suggested that pesticide drift from agricultural areas to residential environments may have occurred. No seasonal effect on distribution of pesticides in dust was found, indicating that pesticides could be routinely used in Taiwan regardless of season. Compared with other international studies, this study shows relatively high levels of chlorpyrifos but low levels of pyrethroids (i.e., cypermethrin), reflecting a different pattern of pesticide use in Taiwan. Further studies need to be warranted for a better understanding of exposure to pesticides and the associated health effects.
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Poluição do Ar em Ambientes Fechados/análise , Poeira/análise , Monitoramento Ambiental/métodos , Praguicidas/química , Feminino , Habitação , Humanos , Projetos Piloto , Gravidez , População Rural , Taiwan , Adulto JovemRESUMO
We estimated the daily intakes of chlorpyrifos and cypermethrin via ingestion of indoor dust and outdoor soils using the Stochastic Human Exposure and Dose Simulation Model on a probabilistic approach for Taiwanese young children. Variables for the estimation, such as concentration, ingestion rate, and body weight, were adopted from previous studies. Monte Carlo simulation was performed with 1,000,000 iterations to simulate a single daily intake, which was shown in terms of percentage of the Acceptable Daily Intake (ADI) of either insecticide. The daily intakes are minimal with a 99% probability, but go up steeply at the 99.9th percentile (13.1% and 20.0% of the ADIs of chlorpyrifos and cypermethrin, respectively). The sensitivity analysis indicates that concentration is the most determinant variable for daily intake estimation, suggesting that high intakes may occur when insecticide concentrations are elevated. Compared to the data of daily intakes via dietary ingestion of vegetables derived from a previous study, the estimated non-dietary intakes are negligible until reaching the highest percentile. Consequently, the non-dietary ingestion exposure to either insecticide is commonly low for young children in Taiwan’s homes, unless high contamination (e.g., indoor insecticide application) occurs in the environment. Care has to be taken to avoid high contamination indoors.
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Clorpirifos/análise , Poeira/análise , Exposição Ambiental/análise , Piretrinas/análise , Solo/química , Criança , Pré-Escolar , Dieta , Habitação , Humanos , Inseticidas , Método de Monte Carlo , TaiwanRESUMO
Borneol is a monoterpene that is widely used in traditional Chinese medicine. There are two different products sold in Taipei's traditional Chinese medicine market, natural and chemically synthesized borneol. Chemically synthesized borneol contains four stereoisomers, (+)-isoborneol, (-)-isoborneol, (-)-borneol, and (+)-borneol. The ratio of these four isomers in chemically synthesized and natural borneol products was determined by gas chromatography mass spectrometry. A huge variation between these products is highlighted in this survey. The results suggest that the Food and Drug Administrations in Asian countries should establish a regulatory standard regarding the ratio of the four different borneol isomers in both natural and chemically synthesized borneol.
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Canfanos/análise , Canfanos/química , Cromatografia Gasosa-Espectrometria de Massas , Medicina Tradicional Chinesa , Estrutura Molecular , TaiwanRESUMO
"Jinchuang ointment" is a traditional Chinese herbal medicine complex for treatment of incised wounds. For more than ten years, it has been used at China Medical University Hospital (Taichung, Taiwan) for the treatment of diabetic foot infections and decubitus ulcers. Three different cases are presented in this study. "Jinchuang" ointment is a mixture of natural product complexes from nine different components, making it difficult to analyze its exact chemical compositions. To further characterize the herbal ingredients used in this study, the contents of reference standards present in a subset of the ointment ingredients (dragon's blood, catechu, frankincense, and myrrh) were determined by HPLC. Two in vitro cell based assay platforms, wound healing and tube formation, were used to examine the biological activity of this medicine. Our results show that this herbal medicine possesses strong activities including stimulation of angiogenesis, cell proliferation, and cell migration, which provide the scientific basis for its clinically observed curative effects on nonhealing diabetic wounds.
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The occurrence of allergic rhinitis (AR) may be significantly influenced by air pollution. This study examined the association between the first occurrence of AR in preschool children and the pre-incident levels of air pollutants in Taiwan. We identified 9960 eligible subjects from a systematic sampling cohort database containing 400,000 insureds of the National Health Insurance from 2007 to 2011 and matched them with the environmental monitoring data from 2006 to 2011 according to the locations of their clinics. Pre-incident levels were determined using the average concentrations of air pollutants one or two weeks prior to the AR diagnoses. Logistic regression analyses were performed to determine any significant relationships between AR and specific air pollutants. The first AR incidence for Taiwanese preschool children, which increased with age, was 10.9% on average; boys appeared to have a higher percentage (14.2%) than girls (8.27%). Among the air pollutants, carbon monoxide (CO) and nitrogen oxides (NOX) were significantly related to AR after adjusting for age and gender (p < 0.05). Because both pollutants are considered to be traffic emissions, this study suggests that traffic emissions in Taiwan need to be controlled to lower the prevalence of children's AR.
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Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Rinite Alérgica/epidemiologia , Emissões de Veículos/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monóxido de Carbono/análise , Pré-Escolar , Monitoramento Ambiental , Feminino , Humanos , Incidência , Masculino , Óxidos de Nitrogênio/análise , Prevalência , Rinite Alérgica/etiologia , Rinite Alérgica/prevenção & controle , Distribuição por Sexo , Taiwan/epidemiologia , Emissões de Veículos/prevenção & controleRESUMO
Mutual enhancement of dermal absorption of N,N-diethyl-m-toluamide (DEET) and oxybenzone (OBZ) has been reported recently with DEET and OBZ being active ingredients of insect repellent and sunscreen, respectively. To assess the reported enhancing effect directly, we used human urinary metabolites as biomarkers; besides, we also sought to determine the best way for concurrent use of these two products without extra absorption of either. Four dermal application methods were used: DEET only (S1), OBZ only (S2), DEET on top of OBZ (S3), and OBZ on top of DEET (S4). Among the study methods, there was a significant difference (p = 0.013), which was attributed to the difference between S1 and S4, suggesting that applying OBZ over DEET on the skin lead to significantly higher absorption of DEET. Using both products in reverse order, (S3) did not result in extra DEET absorption significantly. As for OBZ permeation, no significant difference was observed among the methods. In summary, the enhancement of DEET absorption is confirmed for OBZ being applied over DEET on the skin; should concurrent use of both be necessary, applying sunscreen (OBZ) first and then insect repellent (DEET) with a 15-min interval is recommended.
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Benzofenonas/farmacocinética , DEET/farmacocinética , Repelentes de Insetos/farmacocinética , Absorção Cutânea , Protetores Solares/farmacocinética , Adulto , Benzofenonas/urina , DEET/urina , Feminino , Humanos , Repelentes de Insetos/urina , Masculino , Pele/metabolismo , Adulto JovemRESUMO
Urinary metabolites of DEET of 17 children (5-7 years of age) and 9 adults (23-25 years of age) were examined in the study described in this article. Urine samples were collected from each subject within eight hours after a single dermal application of 10 mL 12% DEET-containing insect repellent. Two metabolites, m-diethylaminocarbonyl benzoic acid (R3N0) and N-ethyl-m-toluamide (RON1), with unchanged DEET, were identified in the urine. The major metabolite was R3NO, which was 78.2% and 46.1% of the total DEET metabolites from children and adults, respectively, indicating that the pathway of ring methyl oxidation predominated. The recovered DEET metabolites were observed significantly more from children (1,116 pg) than from adults (446.2 pg) (p < .001). The difference in dermal absorption, albeit primarily attributed to DEET loading, was found to be related to height by regression analysis. The inverse association between height and dermal absorption of DEET suggests that shorter individuals (i.e., children) are subjected to dermal uptake of DEET. To avoid unnecessary exposure, parents need to be cautious when applying DEET-containing insect repellent on children.
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DEET/urina , Administração Cutânea , Adulto , Criança , Pré-Escolar , DEET/administração & dosagem , DEET/farmacocinética , Feminino , Humanos , Modelos Lineares , Masculino , Absorção CutâneaRESUMO
AIM: The purpose was to examine the effects of non-commercial music on quality of sleep and relaxation indices, including heart rate, mean arterial pressure, and respiratory rate in patients in intensive care units. BACKGROUND: There is currently insufficient scientific knowledge for the effects of music on quality of sleep in critically ill patients. DESIGN: A randomized controlled trial. METHODS: Between January-December 2010, 28 patients aged 39-78 years were randomly assigned to music and control groups. Participants in the music groups listened to non-commercial music for 45 minutes at nocturnal sleep time. In the control group, participants slept with no music. Participants were assessed using vital signs monitors, standardized questionnaire, and polysomnography. Polysomnography sleep was recorded for the first 2 hours of the nocturnal sleep. General estimating equation was applied to analyse data. FINDINGS: Participants in the music group had shorter stage N2 sleep and longer stage N3 sleep in the first 2 hours of the nocturnal sleep and improved self-reported sleep quality, compared with those in the control group. The music group patients also had significantly lower heart rates than those in the control group. The intensive care units patients experienced fragmented sleep with a high frequency of awakenings and severe reduction in random eye movement sleep during the first 2 hours of the nocturnal sleep. CONCLUSION: The findings provided evidence for nurses to use soothing music as a research-based nursing intervention for intensive care unit patients' sleep improvement.
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Cuidados Críticos/métodos , Musicoterapia/métodos , Relaxamento/fisiologia , Sono/fisiologia , Estimulação Acústica/métodos , Adulto , Idoso , Pressão Arterial/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Polissonografia , Taxa Respiratória/fisiologia , Inquéritos e Questionários , Resultado do TratamentoRESUMO
Dry steam cleaning, which has gained recent attention as an effective method to reduce house dust mite (HDM) allergen concentration and loading in carpets, was evaluated in this study for its efficacy in lowering levels of polycyclic aromatic hydrocarbons (PAHs) as well as HDM allergens. Fifty urban homes with wall-to-wall carpets, mostly low-income and with known lead contamination, were studied in 2003 and 2004. Two carpet-cleaning interventions were compared: Repeated HEPA (High Efficiency Particulate Air filtered) vacuuming alone and repeated HEPA vacuuming supplemented with dry steam cleaning. Vacuum samples were collected to measure carpet loading of dust and contaminants immediately before and after cleaning. Paired comparisons were conducted to evaluate the effectiveness of the cleaning protocols in reducing the levels of PAHs and HDM allergens in carpets. The results indicated that both cleaning methods substantially reduced the loading of PAHs and HDM allergens as well as dust in carpets (p < 0.0001). The reductions in loading of dust (64.4%), PAHs (69.1%), and HDM allergens (85.5%), by dry steam cleaning plus repetitive HEPA vacuuming were larger than the reductions by regular HEPA vacuuming alone: dust (55.5%), PAHs (58.6%), and HDM allergens (80.8%), although the difference was statistically significant only for dust and PAHs. We conclude that intensive HEPA vacuum cleaning substantially reduced the loading of PAHs and HDM allergens in carpets in these urban homes and that dry steam cleaning added modestly to cleaning effectiveness.