高分子聚羧酸-纳米Fe3O4磁性复合颗粒的制备及其对水中对羟基苯甲酸酯类化合物的吸附作用

采用悬浮聚合法制备高分子聚羧酸-纳米Fe₃O₄磁性复合颗粒(PC-NMPs)。通过热重差热分析(TGA)、有机元素分析(EA)、原子吸收光谱(AAS)、X-射线衍射(XRD)、红外光谱(IR)、透射电镜(TEM)、振动样品磁强计(VSM)对合成的磁性复合颗粒进行了组成、结构、形貌、磁性等表征,并研究了其吸附和去除水中对羟基苯甲酸酯类化合物(Parabens)的性能。结果表明：合成的磁性复合颗粒平均粒径为100～150 nm,饱和磁化强度为10.66 emu/g,剩余磁化强度为0.61 emu/g,矫顽力为14.96 Oe;该磁性复合颗粒对4种常用的对羟基苯甲酸酯类化合物(Parabens)的等温吸附线基本符合Langmuir模式,对羟基苯甲酸甲酯(MPB)、对羟基苯甲酸乙酯(EPB)和对羟基苯甲酸丙酯(PPB)的饱和吸附量为556 mg/g;对羟基苯甲酸丁酯(BPB)的饱和吸附量为588 mg/g。该复合颗粒能有效去除水中对羟基苯甲酸甲酯类化合物,是潜在的环境激素吸附剂和去除剂。该复合颗粒表面富含羧基可与Parabens类化合物形成氢键、苯环间存在π-π相互作用,有利于吸附过程快速有效地进行。     

Substance flow analysis of parabens in Denmark complemented with a survey of presence and frequency in various commodities

Parabens are commonly used as preservatives due to anti-bactericidal and anti-fungicidal properties and they are ubiquitously present in personal care products, pharmaceuticals, food, industrial and domestic commodities. They are suspected of causing endocrine disrupting effects to aquatic organisms and adverse effects in humans and, thus, it is highly relevant to identify and quantify their sources and transportation pathways in the urban environment. Here a substance flow analysis (SFA) was performed in order to map and comprehend the substances' flow on a national basis. Many household commodities were found to contain parabens; cleaning detergents, slimy toys, and water-based paint. The presence and concentration of parabens are regulated in cosmetics and food. Use of parabens in pharmaceuticals as excipients is documented in Denmark. The import of parabens is increasing; although the number of industrial parabens containing commodities is decreasing and manufacturer reports phase-out of parabens. The vast majority of the paraben containing commodities has a durability of 18-30 months, thus the average lifetime of the paraben stock is perceived to be limited. The inflow was ca. 154 tonnes via pure chemicals and 7.2-73 tonnes via commodities in 2004. This corresponds to an average wastewater concentration of 640-900 microg/L, when excluding discharge to solid waste, soil, biodegradation and metabolism. This is in the same order of magnitudes as can be found in industrial wastewater but higher than that seen in domestic wastewater. The data needed for the SFA is sparse, dispersed, and difficult to access and associated with a great deal of uncertainty.     

GC-MS analysis and ecotoxicological risk assessment of triclosan, carbamazepine and parabens in Indian rivers

Pharmaceutical and personal care products are used extensively worldwide and their residues are frequently reported in aquatic environments. In this study, antiepileptic, antimicrobial and preservative compounds were analyzed in surface water and sediment from the Kaveri, Vellar and Tamiraparani rivers, and in the Pichavaram mangrove in India by gas chromatography-mass spectrometry (GC-MS). The mean concentration of carbamazepine recorded in the Kaveri River water (28.3 ng/L) was higher than in the other rivers and the mangrove. Because carbamazepine is used only in human drugs, this may reflect the relative contributions of human excretions/sewage in these rivers. The mean triclosan level in the Tamiraparani River (944 ng/L) was an order of magnitude greater than in the other water systems, and the concentrations at two of the sites reported here (3800-5160 ng/L) are, to our best knowledge, among the highest detected in surface waters. Sediment levels were, however, comparable with other sites. We conclude that industrial releases are likely major contributors of triclosan into this river system. Among parabens, ethyl paraben was predominantly observed. Hazard Quotients suggest greater environmental risks for triclosan than for carbamazepine and parabens. This is the first study on antiepileptic, antimicrobial and preservatives in rivers and mangroves from India.     

Determination of parabens in pharmaceutical formulations by solid-phase microextraction-ion mobility spectrometry

Solid-phase microextraction (SPME) coupled with ion mobility spectrometry (IMS) was used for the detection and quantitation of 4-hydroxybenzoate preservatives, methylparaben, ethylparaben, propylparaben, and butylparaben, in commercial pharmaceutical products. For the first time, SPME-IMS is described for the simultaneous detection, separation, and quantitation of multiple analytes in complex matrixes. The parabens are extracted from the samples using SPME, and the analytes on the fiber are heated by the IMS desorber unit and vaporized into the drift tube. The four preservatives differing only by a methyl group were separated in less than 18 ms. The analytical procedure was optimized for fiber coating selection, extraction time, sample pH, sample volume, ionic strength, and IMS conditions. Separation characteristics such as resolution, theoretical plates, and drift times of the parabens were also evaluated based on the direct interfacing of SPME to IMS. The conditions were tested using six over-the-counter topical products containing various combinations of preservatives. Analysis of the samples by SPME-IMS using benzyl paraben as an internal standard yields good comparison to an HPLC method, thereby reinforcing the applicability of this technique as a method for routine analysis. Limits of detection were 10 ng/mL for methylparaben and ethylparaben and 5 ng/mL for propylparaben and butylparaben. Good linearity range and reproducibility of less than 8% were obtained.     

Automatic searching and evaluation of priority and emerging contaminants in wastewater and river water by stir bar sorptive extraction followed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

A new analytical method based on stir bar sorptive extraction (SBSE), followed by comprehensive two-dimensional gas chromatography (GCxGC-TOF-MS), has been developed for the automatic searching and evaluation of nonpolar or semipolar contaminants in wastewater and river water. The target compounds selected were 13 personal care products (PCPs), 15 polycyclic aromatic hydrocarbons (PAHs) and 27 pesticides. Excellent results have been obtained in terms of separation efficiency and also in terms of compound identification. Exceptional method detection limits were achieved applying the optimized method, at or below 1 ng/L for most of the compounds in real samples. The reliable confirmation of analyte identity was possible at this low concentration level, even for typically troublesome compounds such as the PAHs. The other validation parameters were good. In addition to obtaining analytical information such as identification and quantification of target analytes, it is also possible to screen for nontarget compounds or unknowns. New contaminants have been identified in the wastewater effluents and river water samples, such as cholesterol and its degradation products, pharmaceuticals, industrial products, other pesticides, and PCPs. The multidimensional information generated by the instrument can also be used by the researchers for contrasting samples and identifying, much more easily, the major differences between samples. We have used this feature to propose studies of comparison between the fingerprinting of different water samples, such as the contamination variation along a river affected by the discharge of urban wastewaters and also the contamination variation over a period of time in the effluent. Results show that the most frequently detected contaminants (and the contaminants detected at higher concentrations) were the PCPs. The musk fragrances galaxolide and tonalid were the most concentrated compounds in the samples. The pesticides and PAHs were present at much lower concentration than PCPs.     

Three decades of TBT contamination in sediments around a large scale shipyard

Tributyltin (TBT) contamination in sediments was investigated in the vicinity of a large-scale shipyard in the years after the implementation of a total ban on the use of TBT based antifouling paints in Korea. Extremely high level of TBT (36,292 ng Sn/g) in surface sediment was found at a station in front of a drydock and near surface runoff outfall of the shipyard. TBT concentration in surface sediments of Gohyeon Bay, where the shipyard is located, showed an apparent decreased TBT concentration gradient from the shipyard towards the outer bay. The vertical distribution of TBT contamination derived from a sediment core analysis demonstrated a significant positive correlation (r² = 0.88; p < 0.001) with the annual tonnage of ship-construction in the shipyard within the past three decades. TBT concentrations at six stations surveyed before (2003) and seven years after (2010) the total ban showed no significant differences (p > 0.05). Despite the ban on the use of TBT, including ocean going vessels, surface sediments are still being heavily contaminated with TBT, and its levels well exceeded the sediment quality guideline or screening values.     

Lytic Activity of Lysozyme Relevant to Preservatives – Enzyme Interactions

Abstract

At physiological hydrogen-ion concentration, p-hydroxybenzoate esters have been found to exert a synergistic effect on the lytic activity of lysozyme; the effect being increased with increasing the size of the aliphatic chain. Although the investigated parabens were proved to bind in significant quantities with lysozyme, however, such additives fail to mask the formation of substrate-lysozyme complexes. The observation was further extended to some organic mercurials with essentially similar results.

At different enzyme concentration levels, phonylmercuric acetate was proved to be the most superior potentiator, whereas, methyl paraben displayed a negligible role.

in the light of the findings obtained, the synergistic effect was interpreted on the basis of the preferential orientation of the substrate on the enzyme binding sites. Such an orientation seems to be more accessible in presence of preservatives.     

Lytic Activity of Lysozyme Relevant to Preservatives - Enzyme Interactions

At physiological hydrogen-ion concentration, p-hydroxybenzoate esters have been found to exert a synergistic effect on the lytic activity of lysozyme; the effect being increased with increasing the size of the aliphatic chain. Although the investigated parabens were proved to bind in significant quantities with lysozyme, however, such additives fail to mask the formation of substrate-lysozyme complexes. The observation was further extended to some organic mercurials with essentially similar results.

At different enzyme concentration levels, phonylmercuric acetate was proved to be the most superior potentiator, whereas, methyl paraben displayed a negligible role.

in the light of the findings obtained, the synergistic effect was interpreted on the basis of the preferential orientation of the substrate on the enzyme binding sites. Such an orientation seems to be more accessible in presence of preservatives.     

Overcoming turf battles: developing a pragmatic, collaborative model to improve glycemic control in patients with diabetes

BACKGROUND: Collaboration between primary care physicians (PCPs) and endocrinologists should be the first step in improving care of patients with diabetes. However, the coordination of care between specialists and PCPs often does not work well. At Vanderbilt University Medical Center, a collaborative model between PCPs and endocrinology was used in an effort to improve glycemic control for patients with diabetes. METHODS: In 1998 a project team was formed; the team members attempted to find ways to improve the care of patients with diabetes, specifically patients with poor glycemic control. The team proceeded through ten iterations of the model before reaching one accepted by all-one with clear responsibilities and referral criteria. RESULTS: Survey results indicated a high level of satisfaction with the collaborative model among patients and PCPs. Appropriate referrals to the diabetes improvement program--a 12-week outpatient program consisting of instruction and support in diabetes self-management coupled with adjustment of insulin and oral hypoglycemic medications-increased during the team effort, and a control chart indicated a change in the process that was significant and sustained. The patients enrolled in the program experienced a reduction of mean glycated hemoglobin levels from 9.2% at entry to 7.5% after 3 months (p < 0.05). DISCUSSION: An initial first step to improving care is to create an environment of trust and collaboration between the PCPs and specialists who assist in that care. After this collaboration has been established, many of the improvements identified in other studies can more easily be implemented.     

Commentary: Research Emphasis and Needs for the Environmental Field in the 1990s

The treatment, storage, disposal, and control of heavy metals to prevent their dispersal in the environment has seen increased attention over the last few years. There has been growing concern for the presence and contamination associated with heavy metals in both our water supplies and soils. Elements such as mercury (Hg) and cadmium (Cd) exhibit human toxicity at extremely low concentrations; elements such as silver, chromium, copper, zinc, and lead also exhibit toxic properties to humans, although the concentrations are orders of magnitude higher than those required for Cd or Hg toxicity. One of the most publicized cases of industrial heavy metal pollution involved the discharge of the catalyst methylated mercury chloride into Minamato Bay, Japan, from a plastic manufacturing factory. Microorganisms converted the sedimented compound to monomethyl-mercury, which led to an enrichment of this toxic metal in fish consumed by local people, some of whom succumbed to diseases caused by severe chronic mercury poisoning.

Similarly, concern has also increased over the past decade for the management, treatment, storage, and disposal of hazardous waste. This concern has arisen in part due to such events as the eruption of Mount St. Helens in Washington State (which demonstrated how “local” events can affect air quality hundreds of miles away), “acid rain,” the “greenhouse effect,” and accidents such as the Bhopal tragedy. Because hazardous waste can have such large affects on both human health and the environment, I have developed a list critical needs and research areas that should be addressed during the next decade to respond to these issues.     

Research productivity in soil science in the Philippines

Understanding the direction and magnitude of soil science publication in the Philippines is crucial in formulating research priorities and funding allocation. There is no consensus on the current state of soil science publication in the Philippines, thus this study was conducted to elucidate the trend in the soil science publication. We conducted an in-depth analysis on the total number of publications and the total number of citations of soil science publications collected from Thomson ISI database. Results revealed an upsurge in soil science publication from 1970 to 2000 with no indication that this trend is slowing down. Increases in the number of citations with time are consistent with increases in the total number of publications (r = 0.93; p < 0.05). Results further revealed that the soil science publication in the Philippines is biased towards rice research particularly soil water with very few studies were published for plant nutrition and soil chemistry. The present study highlights the need for a paradigm shift in soil science research from mostly rice related research to environmental research. Ways to increase soil science publication among Filipino soil scientist’s particularly in academic institutions is proposed. Finally, since only a few government-funded research have been published, future studies should stress on identifying factors that influence scientific productivity of most soil scientists in the Philippines.     

Risk assessment of polycyclic aromatic hydrocarbons in a Mediterranean semi-enclosed basin affected by human activities (Abu Qir Bay, Egypt)

The contamination of sediments and mussels sampled from Abu Qir Bay by polycyclic aromatic hydrocarbons (PAHs) was investigated. Concentrations of PAHs recorded in the bay sediments ranged from <MDL to 2660 μg/kg dw. In general, concentrations of PAHs in mussels were higher than their corresponding sediment concentrations reflecting their great bioavailability (242–3880 μg/kg dw). The highest concentration was observed in the western part of the bay, a location affected by intensive shipping activities. The distribution pattern of PAHs was similar for mussels and sediments, particularly for sediments characterized by high contamination level, and they were dominated by the high molecular weight PAHs (4–6-rings). Applying different PAHs ratios, it was found that PAHs originated predominantly from the pyrogenic source either from the combustion of grass, wood and coal (majority of the samples) or from petroleum combustion (harbour area). The output of a Screening Level Ecological Risk Assessment (SLERA) on the bay sediments revealed that adverse ecological effects to benthic organisms are expected to occur in only one sample, and thus PAHs are not considered as contaminants of concern in Abu Qir Bay. Also adverse health effects are not expected to occur from the consumption of the investigated mussels with respect to PAHs in Abu Qir Bay.     

Effect of Si,Mn and Al on the Microstructure and Mechanical Properties of ADI Weld Metal

The effects of Si,Mn and Al on the microstructure and mechanical properties of ADl weld have been studied.The microstructure of ADl weld metal mainly consists of bainitic ferrite and retained austenite.Mechanical properties of Adl weld increase with increasing Si content,but an excess of Si(3.79%) results in decreasing the austemperability owing to decreasing the carbon content of the matrix austenite.Mn increases the retained austenite volume fractio,but the ductility and impact toughness of weld obviously decrease with increasing Mn content because of increased amount of martenite and twin martenite.In the range of 0.13%-0.64%Al ,increasing Al content favours improving the mechanical properties of ADl weld.Therefore,it is very important to select suitable Si,Mn and Al contents to improve mechanical properties of ADl weld .     

Error specific restrictions for older drivers: promoting continued independence and public safety

OBJECTIVES: To describe a population of older drivers with driving restrictions, their most common restrictions, and to compare restricted drivers to their safe and unsafe counterparts. Safe drivers are those who do not commit hazardous errors or traffic violations. Unsafe drivers are those who commit hazardous errors and/or traffic violations that place them in hazardous situations. Restricted drivers are those who have committed traffic or rule violations only under certain driving conditions. DESIGN: A retrospective, cross-sectional study with mixed methodology. SETTING: A clinical driving evaluation program within an academic geriatrics department. PARTICIPANTS: Drivers age 60+ (N=108) referred for clinical driving evaluation and who consented to allow their data to be used for research purposes. INTERVENTION: Drivers performing at an intermediate level driving fitness were issued error specific driving restrictions. MEASUREMENT: Driving evaluation included clock drawing test (CDT), mini-mental status exam (MMSE), Trailmaking, geriatric depression scale (GDS), and simulated driving. RESULTS: The three most common restrictions were limited driving distance (N=8), limited driving time (N=8), and daytime only driving (N=8). Safe, restricted, and unsafe drivers significantly differed on MMSE (F[2,104]=10.75, p<0.001), Trailmaking Part B (F[2,76]=9.96, p<0.001), CDT (F[2,98]=29.88, p<0.001), and total number of hazardous errors (F[2,97]=39.06, p<0.001). Tukey's test indicated safe and restricted drivers scored significantly better than unsafe drivers on MMSE (safe: p<0.001; restricted: p=0.008), CDT (p<0.001), and hazardous errors (p<0.001). Restricted and unsafe drivers required significantly more time to complete Trailmaking B than safe drivers (p=0.004). CONCLUSION: Preliminary data indicate restricted drivers perform more like safe than unsafe drivers. Driving simulation is instrumental in discerning error specific limitations and categorizing patients as conditionally safe. This clinical evaluation pilots an effective alternative to premature driving cessation.     

Single-cell fluorescence imaging using metal plasmon-coupled probe 2: single-molecule counting on lifetime image

Multiple Alexa Fluor 647-conjugated concanavalin A (conA) molecules were covalently bound to a single 20 nm silver particle to synthesize metal plasmon-coupled probes (PCPs). The fluorescence images were recorded by scanning confocal microscopy in both intensity and lifetime. The brightness of PCPs was 30-fold brighter than those of free conA and the lifetime of PCPs was shortened dramatically. PCPs were used to label T-lymphocytic ( PM1) cells. The emission spots by PCPs bound on the cell surfaces were separated clearly from the cell images by autofluorescence due to the brighter signal and shorter lifetime of PCPs. The emission spots by PCPs were also scanned in three dimensions to count the distribution of bound fluorophores on the cell surfaces. The metal-associated fluorophores thus are suggested using as novel molecular imaging agents to quantify the components and describe their distributions on the cell surfaces.     

Chemistry and application of flexible porous coordination polymers

Abstract

Porous coordination polymers (PCPs), which are microporous materials, have been given much attention from both scientific and commercial aspects regarding their application to gas storage, gas separation and catalytic reaction because of the regularity of their pore shape and pore size, accompanied with the functionality. Moreover, in recent years, flexible PCPs, which are structurally transformable depending upon external stimuli, have been attractive because they provide unique properties, dissimilar to those of zeolites. In this review, the chemistry and application of flexible crystalline PCPs are summarized and discussed.     

Effects of low-temperature duplex coatings on the abrasive and erosive behavior of ADI

This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies, which have the well-known advantage of low processing temperature (EN = 90 °C and CAE = 230 °C), to treat the austempered ductile iron (ADI) substrate. The eligibility of applying the EN and CAE-CrTiAlN duplex coatings on ADI, along with the coating properties, such as structure, roughness, and adhesion, was evaluated and analyzed. Wear and erosive tests were also performed to further understand the effects of the coatings on the abrasive and erosive behaviors of ADI. The results show that the unique microstructure of ADI does not deteriorate after EN and CAE treatments. With regard to erosion resistance, the duplex coated specimens perform better than do the uncoated and monolithic EN or CrTiAlN coated ones. Moreover, the duplex coatings achieve a remarkable reduction in ADI's friction coefficient from 0.85 to 0.6.     

A study on microstructure and toughness of copper alloyed and austempered ductile irons

In this study, ductile irons with and without 1 wt% copper alloy were austempered to become austempered ductile irons (ADIs). Microstructure, impact toughness, and fracture toughness were evaluated to determine how both the copper alloying and austempering treatments influenced the toughness properties of ductile irons. The results show that, because copper increases the retained austenite content in ADI, the Cu-alloyed ADI has better impact toughness and fracture toughness (K_IC value) than does the unalloyed one. In particular, the impact toughness and the fracture toughness of ADI could be efficiently improved by treating the Cu-alloyed ductile iron at a higher austempering temperature (360 °C) to obtain more retained austenite in its microstructure.     

Effect of modified atmosphere packaging and superchilled storage on the shelf‐life of farmed ready‐to‐cook spotted wolf‐fish (Anarhichas minor)

Modified atmosphere packaging (MAP) combined with superchilling (?1°C) was evaluated as a mild preservation method for farmed spotted wolf‐fish (Anarhichas minor). Portions were packaged in air and in CO2:N2 (60%:40%) atmosphere with a gas:product ratio of approximately 1, at superchilled (?1.0°C ± 0.2°C) or chilled (+4.0°C ± 0.2°C) temperatures. A reduced bacterial growth (p < 0.001), measured as aerobic plate counts (APC) and psychrotrophic bacteria, was observed in modified atmosphere (MA) packaged wolf‐fish at both ?1°C and +4°C, compared to portions in air. MA‐packaged wolf‐fish had improved odour and flavour scores (p < 0.05), but also a higher drip loss than fish stored in air. A shelf‐life of 15 days was obtained at ?1°C for MA‐packaged fish compared to 8–10 days in air, and at 4°C the shelf‐life was 13 days in MA and 6–8 days in air. Copyright © 2006 John Wiley & Sons, Ltd.