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Inefficiency and resource misallocation in the financial system, coupled with a shortage of traditional financial services, have hindered export product quality improvement in China. Against this backdrop, there is an evident need to examine the dynamics between digital finance and export product quality. Hence, this study focuses on the impact of digital finance on export product quality upgrades in China. The examination draws on panel data of 39,387 firm-level samples from 2011 to 2014. Empirical results show that digital finance helps upgrade export product quality by enhancing enterprises' financial stability. Moreover, the positive effect of the depth of digital finance usage is more pronounced than that of the breadth of digital finance coverage. Our findings imply that China must continue deepening the digital financial market and expand and improve the scope and efficiency of financial services. [ABSTRACT FROM AUTHOR]

Different from the overwhelming evidence in support of the negative effect of economic policy uncertainty on firm value, our findings show that economic policy uncertainty has positive impact on firm value in firms with high managerial ability using the firm-level data from China over the time period 2003 to 2020. Moreover, our mechanism analyses reveal that firms with high managerial ability differ from those with low managerial ability by conducting more acquisitions and innovation activities and improving cost efficiency when faced with high economic policy uncertainty. [ABSTRACT FROM AUTHOR]

Periodontitis is among most common human inflammatory diseases and characterized by destruction of tooth-supporting tissues that will eventually lead to tooth loss. Diabetes mellitus (DM) is a group of metabolic disorders characterized by chronic hyperglycemia which results from defects in insulin secretion and/or insulin resistance. Numerous studies have provided evidence for the inter-relationship between DM and periodontitis that has been considered as the sixth most frequent complication of DM. However, the mechanisms are not fully understood yet. The impact of DM on periodontitis through hyperglycemia and inflammatory pathways is well described, but the effects of DM on oral microbiota remain controversial according to previous studies. Recent studies using next-generation sequencing technology indicate that DM can alter the biodiversity and composition of oral microbiome especially subgingival microbiome. This may be another mechanism by which DM risks or aggravates periodontitis. Thus, to understand the role of oral microbiome in periodontitis of diabetics and the mechanism of shifts of oral microbiome under DM would be valuable for making specific therapeutic regimens for treating periodontitis patients with DM or preventing diabetic patients from periodontitis. This article reviews the role of oral microbiome in periodontal health (symbiosis) and disease (dysbiosis), highlights the oral microbial shifts under DM and summarizes the mechanism of the shifts. [ABSTRACT FROM AUTHOR]

Feathers are important economic products. Anser cygnoide (AC) is superior in reproduction, growth and feather quality, while Anser anser (AA) has an advantage in feather yield. Understanding the development of feather follicles facilitates deliberate crossbreeding. Here, we compared feather follicles morphogenesis between AC and AA. Feathers and dorsal skin were sampled at multiple embryonic days to investigate feather phenotypes, feather follicle morphology and the expression of hub molecules (FZD4, β-catenin, LEF1, TCF4 and c-Myc) in the Wnt signalling pathway. We found a marked difference in plumage colour between the two breeds. Feather colour in AA has undergone a 'black dorsum' stage and cavity formation in AC was earlier. Furthermore, different trends in molecular hub expression helped explain the phenotypical and morphological differences: the upregulated Wnt signals in AC at E12 and/or E15, as well as in AA at E18, were associated with early epidermal placode formation and cavity formation in AC, also, related to the development of the secondary feather follicles and 'black dorsum' in AA. Summarily, breed-specific expression patterns of Wnt signalling pathway between AC and AA might participate in the shaping of breed-specific feather follicles morphogenesis and feather phenotypes. This work provides references for feather follicles development in geese. [ABSTRACT FROM AUTHOR]

Objective: Few studies have examined factors affecting the high frequency of hospitalization for pediatric asthma. This study identifies individual and environmental characteristics of children with asthma from a low-income community with a high number of hospitalizations. Methods: The study population included 902 children admitted at least once to a children's hospital in South Texas because of asthma from 2010 to 2016. The population was divided into three groups by utilization frequency (high: ≥4 times, medium: 2–3 times, or low: 1 time). Individual-level factors at index admission and environmental factors were included for the analysis. Unadjusted and adjusted multivariate ordered logistic regression models were applied to identify significant characteristics of high hospital utilizers. Results: The high utilization group comprised 2.4% of total patients and accounted for substantial hospital resource utilization: 10.8% of all admissions and 13.5% of days stayed in the hospital. Patients in the high utilization group showed longer length of stay (LOS) and shorter time between admissions on average than the other two groups. The multivariate ordered logistic regression models revealed that age of 5–11 years (OR = 0.57, 95%CI = 0.35–0.93), longer LOS (2 days: OR = 1.80, 95%CI = 1.15–2.84; ≥3 days: OR = 3.38, 95%CI = 2.10–5.46), warm season at index admission (OR = 1.49, 95%CI = 1.01–2.20), and higher average ozone level in children's residential neighborhoods (OR = 1.78, 95%CI = 1.01–3.14) were significantly associated with a higher number of asthma hospitalizations. Conclusions: The findings suggest the importance of monitoring high hospital utilizers and establishing strategies for such patients based on their characteristics to reduce repeated hospitalizations and to increase optimal use of hospital resources. [ABSTRACT FROM AUTHOR]

Hypertension is highly prevalent among people living with HIV (PLWH). We sought to characterize the hypertension incidence among PLWH on antiretroviral therapy, focusing on the effect of change in general and abdominal obesity on hypertension during follow-up. This was a prospective analysis of 229 treated PLWH aged over 40 years without hypertension at baseline. Overall a median follow-up of 2.9 years, 26.2% PLWH developed hypertension. In multivariable models, compared to those without obesity measures at both baseline and follow-up visit, PLWH with general obesity at both occasions (adjusted odds ratio [aOR] = 3.83, P = 0.006) or at baseline only (aOR = 5.45, P = 0.003), abdominal obesity (measured as waist circumference) at both occasions (aOR = 3.87, P = 0.001) or at follow-up only (aOR = 2.27; 9P = 0.060), abdominal obesity (measured as waist-to-hip ratio) at both occasions (aOR = 2.27, P = 0.077) were at increased risk of incident hypertension. Our data show that both general and abdominal obesity especially in the persistent status increase the hypertension risk in treated PLWH. [ABSTRACT FROM AUTHOR]

Although plastic materials play an essential role in life, the intensive production of plastic products and mismanagement of plastic waste worldwide have resulted in microplastic pollution. The two major characteristics of environmental microplastics are having small size and resistance to degradation, which make microplastics a persistent organic pollutant. As microplastic pollution has been observed in diverse environmental matrices, it has attracted great attention of scholars globally. Over the last decade, scholars have mainly documented the particle properties of microplastics, such as size, shape or color and their adverse effects on organisms. However, no research has updated on environmental microplastics from the perspective of multi-media. Our review first summarized the literature in the occurrence, distribution, and characteristics of microplastics in three kinds of environmental matrices (water, soil, and air) to the public. We then identify the methodological challenges in researches and discuss the advantages and limitations of popular methods to analyze environmental microplastics. Eventually, our paper highlights the current challenges and proposes suggestions for the future research on microplastic pollution. [ABSTRACT FROM AUTHOR]

Background: This study aims to describe TBI-related hospitalizations for the whole population and identify factors associated with in-hospital mortality among elderly (≥65 years) patients hospitalized with TBI in Texas. Methods: Using Texas Hospital Discharge Data from 2012 to 2014, TBI-related hospitalizations were identified using International Classification of Diseases – Ninth Revision – Clinical Modification (ICD-9-CM) codes. Rates for age and gender were estimated using U.S. Census data. Univariate and multivariate analyses were used to identify factors associated with in-hospital mortality among those aged at least 65 years. Results: There were 51,419 TBI-related hospitalizations from 2012 to 2014 in Texas. Falls were the leading cause of TBI-related hospitalizations 6235 (36.64%), 6595 (38.40%), and 5412 (37.59%) for 2012, 2013, and 2014, respectively. Males had higher rates of hospitalizations while rates were highest for those above 80 years of age. Compared to Whites, Hispanics had 1.18 higher adjusted odds of in-hospital mortality [OR = 1.18: 95% CI (1.01–1.40)]. Similarly, adjusted odds of in-hospital mortality were higher among males [OR = 1.55: 95% CI (1.36–1.77)]. Conclusion: This study provided evidence of demographic disparities in the burden and outcome of TBI in Texas, findings could serve as a foundation for targeted TBI prevention interventions. [ABSTRACT FROM AUTHOR]

Low baseline testosterone level has been associated with the development of risk factors for cardiovascular disease such as insulin resistance and obesity. In addition to the absolute testosterone level, remarkable changes in testosterone level may have an acute effect on cardiovascular disease development and progression, which has been rarely investigated. In this study, we used a clinical dataset of 376 hypogonadal men whose testosterone levels were measured every six months for up to 11 years from a registry study in Germany, and conducted survival analyses to investigate the effect of testosterone changes since the last visit (time-varying) on the risk of cardiovascular events. Given the potential discrepancies in comorbidity conditions among patients with prior cardiovascular events and those without, all the analyses were stratified by patients' prior cardiovascular event status. We found the effects were not different among patients with prior cardiovascular events and those without. Regardless of patients' prior cardiovascular event status, patients with larger testosterone declines (≥3.12 nmol/L, 90th percentile) since the last visit were more likely to experience myocardial infarction. In conclusion, recent pronounced testosterone drop-offs may affect the risk of cardiovascular events among hypogonadal men. Future longitudinal studies are needed to confirm our exploratory study findings. [ABSTRACT FROM AUTHOR]

Amelioration of saline soil is a requisite in order to increase crop productivity. A soil incubation study was performed for 60 days using digestate, humic acid, calcium humate and their combinations to investigate the influence on physical, chemical, microbial and enzyme activities of saline soil. Overall, digestate combined with calcium humate followed by humic acid treatments have shown their potency in decreasing the soil pH, electrical conductivity (EC), and sodium ion (Na+) concentration, and increase in potassium ion (K +), calcium ion (Ca 2+), magnesium ion (Mg 2+), mean weight diameter (MWD), soil enzyme activities, microbial biomass carbon (MBC), MBC: microbial biomass nitrogen (MBN) and soil respiration than control. The digestate, humic acid individually and their amalgamation evidenced greater MBN among all the treatments. The digestate alone efficiently improved the soil properties than humic acid and calcium humate individual groups except for the MWD where it is pronounced more in the latter groups. The greater metabolic quotient (qCO2) was observed in control than organic matter amended treatments indicating the stress conditions. The increase in water-extractable organic matter (WEOM) with minimal aromaticity (specific ultraviolet absorbance at 254 nm-Suva 254) in integrated amendments comprising groups, laid the ground reason to improve the properties of saline soil. Therefore, this study concludes that the fusion of fresh and humified substrates could facilitate reclamation. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether testosterone replacement therapy (TRT) reduces prostate cancer (PCa) risk via stabilizing serum testosterone (T) levels beyond simply elevating serum T levels and whether TRT reduces PCa risk due to low serum T levels at a young age.Methods: We analyzed data of 776 hypogonadal men from a urology center in Bremerhaven, Germany through 2004-2016 to investigate whether the TRT group has more stable T levels and whether TRT can reduce the risk of PCa due to low serum T levels at an early age. We derived an index, Maximum Decline of T Relative to Baseline (MDRB), to describe the magnitude of T declines and variations over time.Results: We found the TRT group has more stable serum T levels (e.g. smaller drop-offs) during the follow-up period as compared to the non-TRT group, and the mean of MDRB is significantly higher in the untreated group (1.553 nmol/L VS 0.013 nmol/L; p-value < .001). TRT significantly reduces the risk of PCa associated with T deficiency at a young age (p-value = .00087).Conclusions: TRT may reduce PCa risk via maintaining serum T levels within individual's normal range; T surveillance may be needed for males who have low serum T levels at a young age to monitor abnormal variations of T levels and ensure timely treatment when necessary to reduce PCa risk. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of the dynamical behaviours of a class of complex-valued neural networks with mixed time delays and impulsive effect. By separating the complex-valued neural networks into the real and the imaginary parts, the corresponding equivalent real-valued systems are obtained. Some sufficient conditions are derived for assuring the exponential stability of the equilibrium point of the system based on the vector Lyapunov function method and mathematical induction method. The obtained results generalise the existing ones. Finally, two numerical examples with simulations are given to demonstrate the feasibility of the proposed results. [ABSTRACT FROM PUBLISHER]

Background: Fractional concentration of exhaled nitric oxide (FeNO) is recommended by the American Thoracic Society (ATS) as a noninvasive biomarker of airway inflammation. In addition to inflammation, many factors may be associated with FeNO, particularly tobacco exposure; however, only age has been included as an influential factor for children below 12 years. Numerous studies have demonstrated negative associations between tobacco exposure and FeNO levels with self-reported data, but few with an objective assessment of smoking. Methods: Data from the National Health and Nutrition Examination Survey (NHANES) 2007–2012 were analyzed to examine the association between FeNO and active/passive tobacco. Exposure was assessed by both self-report and serum cotinine levels among 11,160 subjects aged 6–79 years old with asthma, or without any respiratory disease. Results: Study results indicated 28.8% lower FeNO, 95% CI [25.2%, 32.3%] and 38.1% lower FeNO, 95% CI: [28.1, 46.2] was observed among healthy and asthmatic participants with serum cotinine in the highest quartile compared to those in the lowest quartile, respectively. Self-reported smoking status and recent tobacco use were also associated with decreased FeNO. Self-reported passive smoking was significantly associated with a 1.0% decrease in FeNO 95% CI [0.0, 2.0] among asthmatic subjects but not among healthy subjects. Conclusions: Active smoking, whether measured by self-report or serum cotinine, was associated with decreased FeNO levels. In addition to age, increased attention should be given to tobacco exposure when using FeNO as a biomarker in clinical practice. Additional research is needed to establish reference value of FeNO considering the impact of tobacco exposure. [ABSTRACT FROM PUBLISHER]

A novel approach to synthesize narrow particle size distribution cationic latex particles based on styrene and butyl acrylate was proposed. The effect of monomer/water ratios, surfactant (cetyltrimethylammonium chloride) concentrations, and monomer compositions on the evolution of particle size, distribution, number, and morphology as a function of monomer conversion was concerned in order to confirm the optimum polymerization condition. As expected, the particle size of the ultima latex increased with monomer/water ratios and styrene contents decreased with increasing surfactant concentrations. Continuous nucleation phenomena occurred when monomer/water ratio was lesser than 30/70, resulting in a gradual increase in the number of particles in the whole polymerization process. Combined with the previous work (Colloid and Polymer Science, 2014, 292: 519–525), it was concluded that particle coagulation easily took place in cationic emulsion polymerization of styrene. Thus, the narrow particle size distribution cationic latexes with particle scale between 50 nm and 80 nm, 30 wt% solid content could be prepared in a short reaction time. [ABSTRACT FROM PUBLISHER]

In hot weather, thermal heat generated by the body, combined with environmental heat from the sun, can lead outdoor workers to experience heat-related stress, severe illness, or even death. The aims of this study were to estimate the prevalence of heat-related symptoms and potential risk factors associated with sun safety–related behavior among Latino farmworkers. Data from interviewer-administered questionnaires were collected from a cross-sectional survey among farmworkers (N = 158) from August to September 2013. Data analysis assessed associations between work activities, sun safety behavior, and the prevalence of heat-related illness (HRI) symptoms among workers. Nearly two thirds (72%) of farmworkers experienced at least one HRI symptom and lacked proper cooling methods when working outdoors. Most workers reported wearing long-sleeved shirts (85%), long pants (98%), and baseball caps (93%). The prevalence of having one HRI symptom was 72% and 27% among workers having three or more HRI symptoms. The majority of farmworkers experience symptoms of HRI and are not provided with proper shade protection when working outdoors. Increased emphasis on administrative controls, particularly educating field supervisors and workers on how to avoid and recognize HRI, should be a priority. [ABSTRACT FROM AUTHOR]

Although regulation of emissions is the primary strategy to reduce air pollution–related morbidity, individual-level interventions are also helpful in mitigating health impacts. We used data from 2007–2008 National Health and Nutrition Examination Survey to study the prevalence of individual-level action among the US adult population if informed of air pollution, and to see if this differed by demographic and health factors. Only 13.5% (95% confidence interval [CI]: 11.6–15.4%) of participants aware of air quality reported changing their individual behaviors. Males (adjusted odds ratio [AOR]: 0.66, 95% CI: 0.56–0.77) and those without cardiovascular disease (AOR: 0.58, 95% CI: 0.47–0.71) were least likely to take action. Results show that individual action was infrequent among the population. Health promotion of individual intervention is necessary, and this effort may need to target specific subgroups of the population. Further studies on effective individual interventions are needed. [ABSTRACT FROM AUTHOR]

The Taiwan Strait plays an important role in water and sediment exchange between the East China Sea and the South China Sea. On 13 July 2013, Typhoon Soulik crossed the Taiwan Strait, causing a significant impact on the strait’s marine system. In this article, we document the use of remote-sensing data to study this impact by comparing sea surface temperature (SST), spatial distributions and concentrations of chlorophyll (Chl-a), and total suspended matter (TSM) in the strait over different time periods. During and after the typhoon, the TSM of the waters near the Minjiang estuary dramatically increased, while Chl-aand SST significantly decreased. To the southeast of Pingtan Island, the SST decreased and Chl-asignificantly increased, causing strong upwelling that lasted eight to ten days. To the northwest of Taiwan Island, Chl-aand the TSM of the coastal waters dramatically increased. The strong cyclonic wind-stress of the typhoon enhanced heat exchange between the water and the atmosphere, and a large amount of rainfall and run-off significantly decreased the SST. During the typhoon, the increased sediment discharged into the strait by rivers, and the re-suspension of seafloor sediment, increased the concentration of TSM in the coastal waters. Seawater with relatively high sediment concentration was transported to the middle of the strait after being carried by wind-induced flows. In the waters near the typhoon’s path, especially in the upwelling area, nutrient-rich bottom water stirred by the typhoon promoted an outbreak of aquatic organisms and significantly increased the probability of a red tide occurrence. [ABSTRACT FROM AUTHOR]

Agriculture consistently ranks among the top hazardous occupations, accounting for a significant number of injuries and fatalities in the workplace. Eastern North Carolina has a significant number of small, independent, family-run, owned, and operated farms. However, little is known about perception, behavior, training, accessibility, or purchasing personal protective equipment (PPE) for safety among farmers in the region. In this study, telephone interviews were conducted among participating farmers between March and June 2012 (N= 129). Univariate and bivariate analyses were conducted to examine associations between PPE behavior and workplace hazards, health-related concerns, and wearing and purchasing PPE. Findings indicated that personal behavior of wearing hearing protection devices (HPDs) and protection from the sun among farmers was low. However, a relatively high percentage of farmers reported wearing PPE when working with agricultural chemicals. Most farmers received training from agricultural extension offices. The findings indicate that, in general, farmers are well aware of the risks associated with occupational hazards and recognize concern for health and safety protection in the workplace. Transitioning these concerns into preventative action remains a challenge and priority for the agricultural health professional. [ABSTRACT FROM AUTHOR]

Abstract—Relieving distribution-line overload is an important measure for boosting the reliability of electric power systems. Increasing capacity and load shifting are the current commonly used methods for relieving distribution-line overload. The present study proposes the use of a new method for relieving distribution-line overload considering the demand response. First, based on the demand elasticity matrix, a control strategy for the electricity price-load-overload degree is formed. This strategy revises the load-level curve and effectively reduces the power-system overload risk. Under electricity price responses, situations of overload are still present, but by using a response strategy based on stimulus demand, this strategy regards the minimum economic loss from overload as the target function for interruptible load cutoff. The influence of different load-interrupt schemes on the degree of relief is discussed. Finally, the study employs data from a specific domestic demonstration area to verify the feasibility of the proposed method. The results reveal that by maximally reducing the line overload risk via demand-response means, the safe operation of distribution lines is ensured. [ABSTRACT FROM PUBLISHER]

Farmers and farmworkers face increased risks of skin cancer from exposure to solar ultraviolet radiation (UVR) when working outdoors. The objective of this study wasto evaluate the evidence from behavioral and intervention studies from the peer-reviewed studies related to sun safety among farmers and farmworkers and identify any gaps in the literature. A comprehensive review was conducted between 1990 and 2013; 22 studies were identified related to behavior and health interventions of sun safety among these targeted groups. The inconsistency of data collection methods makes it difficult to estimate with accuracy any overall meaningful results of behavior. However, from the studies reviewed, farmers and farmworkers most frequently reported wearing some type of hat (23.6%–100%) as a primary method of protection from the sun when working outdoors. Female farmers were more likely than male farmers to use sunscreen and engage in indoor tanning behavior. All sun safety educational interventions studies reviewed reported positive increases in behavioral change. To a large degree, adequate sun protection is lacking and varies geographically among farmers. Although targeted education is key to making improvements on sun protection behavior, aggressive attempts have to be made. Studies related to farmworkers, sun safety behavior, and skin cancer are scarce and more research is needed in this area. [ABSTRACT FROM PUBLISHER]

An investigation of the relationship of air pollution and emergency department (ED) visits for asthma was an opportunity to assess environmental risks for asthma exacerbations in an urban population. A total of 6,979 individuals with a primary discharge diagnosis of asthma presented to 1 of 6 EDs in the Pittsburgh, Pennsylvania, area between 2002 and 2005. Using a case-crossover methodology, which controls for the effects of subject-specific covariates such as gender and race, a 2.5% increase was observed in asthma ED visits for each 10 ppb increase in the 1-hour maximum ozone level on day 2 (odds ratio [OR] = 1.025, p < .05). Particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5) had an effect both on the total population on day 1 after exposure (1.036, p < .05), and on African Americans on days 1, 2, and 3. PM2.5 had no significant effect on Caucasian Americans alone. The disparity in risk estimates by race may reflect differences in residential characteristics, exposure to ambient air pollution, or a differential effect of pollution by race. [ABSTRACT FROM AUTHOR]

To investigate whether folic acid would have toxic effects on fetal cardiac, hepatic, and renal functions, this was the first in utero fetal study testing acute effects of folic acid at the last third of gestation. Folic acid (5 mg/day) or 0.9% saline as the control was intragastricly administrated into pregnant ewes. Both maternal and fetal blood were analyzed for pH, PO2, PCO2, SO2%, hemoglobin, hematocrit, glucose, lactic acid, osmolality, Na++, and K++ concentrations. Maternal and fetal cardiovascular functions were assessed by examining cardiac enzymes and cardiovascular responses in vivo. Fetal hepatic and renal functions were examined by analysis of biochemistry index and renal excretion. Folic acid did not alter the blood values in both ewes and fetuses. Cardiac enzyme activities remained unchanged, and no alteration in cardiovascular responses was observed. Folic acid did not affect fetal urine volume, urine electrolytes, and osmolality. Enzyme activities related to hepatic and renal functions were not changed. In addition, maternal application of folic acid had no effect on maternal and fetal lipid profile. The results showed that folic acid used (5 mg/day) during the last third of gestation did not cause biochemical changes related to cardiac, hepatic, and renal functions in both maternal and fetal sheep, providing new information for use of folic acid during late pregnancy. [ABSTRACT FROM AUTHOR]

In order to investigate the protonation effect of polybenzoxazole, a type of soluble thiophene-based polybenzoxazole (PBOP-Th) is synthesized and characterized by the FTIR, 1H-NMR, elemental analysis, thermogravimetric analysis (TGA), UV-Vis and photoluminescence (PL) spectra. Another polymer aminophenols-based polybenzoxazole (PBOP-Ph) was also synthesized as reference polymer. Unlike usual polybenzoxazoles such as poly(p-phenylenebenzobisoxazole) (PBO) and poly(2,5-thienylbenzobisoxazole) (PBOT), PBOP-Th and PBO-Ph have greatly enhanced solubility due to the introduction of isopropylidene and/or thiophene cycle. The effect of protonation on photophysical properties of polybenzoxazoles is studied by an experimental method for the first time. The 30 nm red shift on the UV-Vis and PL spectra of polymer is observed in methanesulfonic acid (MSA) solution compared with that of polymer in neutral N,N-dimethyl fomamide (DMF) solution, which is believed to be due to the protonation effect. [ABSTRACT FROM AUTHOR]

A novel amphiphilic polymer, APAM, for enhanced oil recovery (EOR), was synthesized by radical copolymerization of acrylamide, dodecyl polyoxyethylene acrylate (DPEA), and N-(1,1,3,3-tetramethyl butyl) acrylamide (TBA), using potassium persulfate-sodium bisulfite as initiator-activator. The aggregation morphological observation of APAM in aqueous and NaCl solutions was performed using scanning electron microscope. The ability of APAM to solubilize and emulsify n-heptane and crude oil was investigated by visual methods, microscopy, and particle size analyses. The results show that APAM forms supramolecular aggregates in aqueous and NaCl solutions and has strong emulsification ability. As a result, the emulsion consisting of APAM aqueous solution and n-heptane (or crude oil) is much more stable than that of HPAM (partially hydrolyzed polyacrylamide, widely used in EOR), indicating a important function of APAM to emulsify oil component. [ABSTRACT FROM AUTHOR]

Nonionic gemini surfactants HBA(EO)80 were synthesized and characterized by means of surface tension measurements. CMCs of two mixed system, nonionic gemini mixed with anionic gemini (HBA(EO)80/C11pPHCNa) and nonionic gemini mixed with anionic monomeric (HBA(EO)80/SL) and the effect of salt on the two mixed system were investigated. Freeze-fracture transmission electron microscopy and scanning electron microscopy were used to investigate the mixed aggregates' morphologies. The results show that large spherical aggregates were formed in the mixed solution, which trend to transfer into micelles with the increases of the salt concentration. [ABSTRACT FROM AUTHOR]

Rheologic properties and the conformations of the mixed system of hydrophobically modified polyacrylamide and surfactants in distilled water with or without NaCl were investigated. The vacuum sublimation freezing-drying technique was employed to maintain the aggregation state of the mixed systems. Scan electron microscopy and transmission electron microscopy were used to investigate microstructure of the mixed systems formed, and obtain the system molecular configuration information. The results showed that the rheologic behavior of the mixed solution revealed by viscosity data and microconformation obtained depend on the salt existence and the hydrophobic group content of the polymer. The relationship between polymer microconformation and the macroscopic properties for the mixed systems was analyzed to explore the aggregating mechanism. [ABSTRACT FROM AUTHOR]

With the vacuum sublimation freezing-drying and rheological techniques, the salt/alkali/surfactant effects on the solution properties and the aggregate conformations of the polymers, synthesized hydrophobically modified poly (acrylamide) (HMPAM), were investigated. The experimental methods included viscosity measurements, the photomicroscopy, scan electron microscopy, and the freeze fracture transmission electron microscopy. The variety of conformations of the ultramolecular aggregates, the hydrophobical region, and the spatial network structures resulted from the hydrophobical interaction were studied. Combined results confirmed that HMPAM could form several of interesting three-dimensional network structures either in distilled water or NaCl solution. The results have revealed the mechanism of the salt/alkali/surfactant effects on the peculiar rheological properties of the solution. [ABSTRACT FROM AUTHOR]

The viscous properties, scanning electronic microscopy (SEM), and water/oil interfacial tension (IFT) of partially hydrolyzed polyacryamide (HPAM) and hydrophobically associating hydrolyzed polyacryamides modified with N-dodecylacrylamide were studied with the objective of investigating the influence on destabilization of emulsions. As expected, the copolymers exhibit significant viscosity enhancing capacity and three-dimensional network structures due to intermolecular hydrophobic associations, and also present high interfacial activities as the IFT decrease with increasing polymer concentration. As a result, the existences of copolymers increased both the viscosity of emulsions and the intensity of interfacial film, in which case slow down the diffusion of demulsifier molecules and enhance the stability of emulsions, finally, the separation of water from oil becomes more difficult. [ABSTRACT FROM AUTHOR]

A MEKC method has been developed for the simultaneous determination of guaifenesin (GF), pseudoephedrine (PE), and dextromethorphan (DM) in capsule dosage form using 50 mM sodium dodecyl sulfate (SDS) added to a pH 8.5 100mM Tris run buffer at a voltage of 25 kV. The method utilized UV detection at 220nm and a 72 cm × 50 μm i.d. uncoated fused-silica capillary. The detection limits for GF, PE and DM were 1000, 500, and 500 ng/mL, respectively for a 5 s injection. The calibration curves were linear over ranges of 100–1000 μg/mL, 15–150 μg/mL and 5–50 μg/mL for guaifenesin, pseudoephedrine and dextro-methorphan, respectively, with sodium benzoate (SB) as internal standard. Coefficients of determination were greater than 0.9989 (n = 12). Precision and accuracy of the method were 0.60–2.18% and 0.44–4.20%, respectively for GF, 1.62–3.15% and 0.33–2.98%, respectively for PE, and 0.19–4.36% and 1.77–6.92%, respectively for DM. In comparison to high-performance liquid chromatography, the MEKC method is simple, capillary columns are low-cost, and there is high-resolution efficiency with a minimal consumption of environmentally friendly chemicals. [ABSTRACT FROM AUTHOR]

The article presents a case study on the behavior and perception of using personal protective equipment (PPE) among commercial landscapers. Landscapers are exposed to several chemicals including pesticides, fertilizer, and fuels, besides outdoor heat, sun's ultraviolet radiation, and poisonous plants and insects. The findings of the study showed that most workers knew about the importance of using PPE, a more robust study is needed to examine the use of safety gear and work-related injuries.