Isolation and characterization of 19 highly polymorphic microsatellite markers in the devil stinger, Inimicus japonicus (Synanceiidae)

Inimicus japonicus, the devil stinger, has an extensive distribution along the coast of China, Japan and the Korean Peninsula. Nineteen highly polymorphic microsatellite markers were isolated and characterized in I. japonicus. Twenty-eight individuals from a wild population were tested for polymorphism using this set of polymorphic microsatellite markers. The number of alleles per locus ranged from 4 to 14. The ranges of observed and expected heterozygosity were 0.500-0.892 and 0.521-0.910, respectively. Significant deviations from Hardy-Weinberg equilibrium were detected at two loci. To the best of our knowledge, these were the first microsatellite loci characterized from the Synanceiidae; they can be used for estimating genetic diversity, population structure studies, parentage analysis, genetic linkage map construction, germplasm classification and identification, gene identification, quantitative trait loci mapping, and marker-assisted selection in breeding of I. japonicus and other species of this family.

Interleukin-10 receptor expression and signalling were down-regulated in CD4⁺ T cells of lupus nephritis patients

Studies have indicated that interleukin (IL)-10 has a pathogenic role in systemic lupus erythematosus (SLE); however, a protective effect of IL-10 in SLE was also observed. Because the exact mechanism of IL-10 signalling in the pathogenesis of SLE is unclear, this study sought to assess the expression and signalling of interleukin-10 receptor (IL-10R) in peripheral leucocytes from patients with SLE. We used flow cytometry to examine the expression of IL-10R1 on different peripheral leucocytes from 28 SLE patients, of whom 14 had lupus nephritis (LN) and 14 were healthy controls. We also examined the effects of IL-10 on phosphorylation of signal transducer and activator of transcription (STAT)-3 and STAT-1 in peripheral blood mononuclear cells (PBMCs) obtained from 13 SLE patients and seven healthy controls. Plasma cytokines were detected by flow cytometric bead array (CBA) techniques. Although IL-10R1 expression levels on each peripheral leucocyte subset from 28 SLE patients and 14 healthy controls were similar, the expression levels on CD4(+) T cells from LN patients were significantly lower than on CD4(+) T cells from controls and SLE patients without nephritis (P < 0·01). IL-10R1 expression levels on CD4(+) and CD8(+) T cells were correlated negatively with the SLE disease activity index (P < 0·01). Additionally, the phosphorylation of STAT-3 was delayed and reduced in PBMCs from LN patients and active SLE patients. Plasma IL-10 levels were significantly higher in LN patients than controls. IL-10R1 expression on CD4(+) T cells and signalling in PBMCs were down-regulated in LN patients, indicating that IL-10 and its receptor may have a special role in LN pathogenesis.

ESAT-6- and CFP-10-specific Th1, Th22 and Th17 cells in tuberculous pleurisy may contribute to the local immune response against Mycobacterium tuberculosis infection

Th1 cell-mediated adaptive immune response is very important but may not be sufficient to control Mycobacterium tuberculosis (M. tuberculosis) infection. The roles of the various T cell subsets and cytokines in the inflammatory processes are not clearly elucidated. We investigated whether Th1, Th22 and Th17 cells mediated cellular immunity at the local site of M. tuberculosis infection in patients with tuberculous pleurisy (TBP). The results showed that the cytokines IFN-γ and IL-22 but not IL-17 were elevated in tubercular pleural fluid. Following stimulation with immune-dominant peptides of early secreted antigenic target-6 (ESAT-6), culture filtrate protein-10 (CFP-10) or Bacille Calmette-Guerin, pleural fluid mononuclear cells expressed high levels of cytokines IFN-γ, IL-22 and IL-17 as revealed by mRNA and protein measurements. In addition, we showed that cytokines IFN-γ, IL-22 and IL-17 were produced in M. tuberculosis-specific immune response by distinct subsets of CD4+ T cells with the phenotype of CD45RA-CD62L-CCR7+CD27+ . Our results demonstrated for the first time that ESAT-6- and CFP-10-specific Th1, Th22 and Th17 cells existed in the patients with TBP and might play an essential role against M. tuberculosis infection. The findings of this study raised the possibility of unravelling the critical targets for therapeutic intervention in chronic inflammatory diseases such as TBP.

Adsorption of polyelectrolyte/surfactant mixtures at the air-water interface: modified poly(ethyleneimine) and sodium dodecyl sulfate

The adsorption of surfactant/polyelectrolyte mixtures of sodium dodecyl sulfate (SDS) and different modified poly(ethyleneimine) (PEI) polyelectrolytes at the air-water interface has been studied using neutron reflectivity and surface tension. Modification of the PEI by the addition of short ethylene oxide (EO) or propylene oxide (PO) groups is shown to have an impact upon the surface adsorption behavior. This is due to a modification of the polymer/surfactant interaction, an increase in the intrinsic surface activity of the modified polyelectrolyte, and changes in the relative importance of surface and solution complex formation. For the polyelectrolyte PEI, there is a marked change in the surface adsorption behavior between the addition of a single EO group and that of the (EO)3 group. The addition of a single EO or PO group to the PEI results in an SDS concentration and solution pH adsorption dependence that is broadly similar in behavior to that of the unmodified PEI/SDS mixture. That is, there is strong surface complexation and adsorption down to low SDS concentrations, and there is evidence of a strong interaction at high pH in addition to the strong electrostatic attraction at low pH. The addition of a larger ethylene oxide group, triethylene oxide (EO)3, results in a surface adsorption behavior that more closely resembles that of a neutral polymer/ionic surfactant mixture, similar to that observed for PEI with a larger ethylene oxide group, notably PEI-(EO)7. In that case, the adsorption of the polymer/surfactant complex is much less pronounced. The adsorption arises predominantly from competition between the polymer and surfactant and indicates a decrease in the polymer/surfactant interaction with increasing pH. That is, increasing the size of the ethylene oxide group induces a transition from a strong surface polymer/surfactant interaction to a weak polymer/surfactant interaction.

Chest imaging findings in children with influenza A H1N1

OBJECTIVE

To assess imaging findings at presentation in children diagnosed with influenza A (H1N1) infection.

METHODS

This is a retrospective observational cohort study conducted at The Children's Hospital affiliated to Soochow University, Suzhou, China between September 2009 and March 2010. Nasopharyngeal swabs and bronchial aspirate samples from 81 children with acute respiratory infections were tested positive for influenza A (H1N1) using quantitative real-time polymerase chain reaction. Chest imaging for these patients was analyzed retrospectively by 2 independent radiologists for the presence and distribution of abnormalities.

RESULTS

Chest radiograph findings consisted of bilateral patchy areas of consolidation (n=48), diffuse areas of air-space consolidation (n=18), and lobar consolidation (n=7). Eight chest x-rays were normal. Abnormalities were observed more frequently in the lower lobes (bilateral [n=66], unilateral [n=7]). Computed tomography (CT) scans were performed in 18 cases with air-space consolidation and interstitial opacities. Cases with diffuse areas of air-space consolidation were followed-up after 3 months by high resolution CT imaging, which showed interstitial thickening.

CONCLUSION

The predominant imaging findings in childhood influenza A (H1N1) were bilateral patchy areas of consolidation, followed by diffuse areas of air-space consolidation, normal radiographs, and lobar consolidation.

Demonstration of a neutral atom controlled-NOT quantum gate

We present the first demonstration of a CNOT gate between two individually addressed neutral atoms. Our implementation of the CNOT uses Rydberg blockade interactions between neutral atoms held in optical traps separated by >8 microm. Using two different gate protocols we measure CNOT fidelities of F=0.73 and 0.72 based on truth table probabilities. The gate was used to generate Bell states with fidelity F=0.48+/-0.06. After correcting for atom loss we obtain an a posteriori entanglement fidelity of F=0.58.

Cellular responses and expression profiling of human bone marrow stromal cells stimulated with enamel matrix proteins in vitro

OBJECTIVES

The aim of this study was to investigate biological effects and gene expression profiles of enamel matrix proteins (EMPs), on human bone marrow stromal cells (HBMSCs), for preliminary understanding of mechanisms involved in promoting periodontal regeneration by EMPs.

MATERIALS AND METHODS

EMPs were extracted using the acetic acid method, and HBMSCs from human bone marrow aspirates were cultured. Attachment levels, level of cells morphologically attenuated, cell proliferation, alkaline phosphatase (ALP) activity and staining of HBMSCs were measured in the absence and in the presence of EMPs. Microarray analysis was performed to detect gene profiles of HBMSCs by treatment with 200 microg/ml EMPs, for 5 days. Four differential genes were selected for validation of the microarray data using real-time PCR.

RESULTS

EMPs promoted proliferation and ALP activity of HBMSCs in a time- and dose-dependent manner, and at a concentration of 200 microg/ml significantly enhanced proliferation and ALP expression. However, there were no significant changes between EMP-treated groups and the control group in cell attachment and cell process attenuation levels. Twenty-seven genes were differentially expressed by HBMSCs in the presence of EMPs. Expressions of 18 genes were upregulated and expressions of nine genes were found to be downregulated. There was good consistency between data obtained from the validation group and microarray results.

CONCLUSIONS

EMPs promoted cell proliferation and differentiation and gene expression profiles of HBMSCs were affected. This may help elucidation of mechanisms involved in promoting regeneration of periodontal tissues by EMPs.

[Viral pathogens of acute respiratory infection in hospitalized children from Suzhou]

OBJECTIVE

To investigate the viral pathogens of acute respiratory infection (ARI) in hospitalized children from Suzhou of China.

METHODS

The nasopharyngeal aspirate samples were obtained from 1,668 hospitalized children with ARI. Common respiratory viruses, including respiratory syncytial virus (RSV), influenza virus A and B, parainfluenza viruses 1, 2 and 3 and adenovirus, were detected using direct immunofluorescence. Human metapneumovirus (hMPV) gene fragments were detected by RT-PCR.

RESULTS

Viral agents were identified in 597 cases (35.8%). RSV was the most frequent (17.6%). RSV infection is more common in children less than 1 year old. A highest detection rate of RSV was found during winter and spring. hMPV was detected in 10.6% of the cases, with a peak detection rate between March and May. Single viral infection was found in 561 cases (33.6%) and mixed viral infection in 36 cases (including 27 cases at age of less than 1 year). RSV and hMPV co-infection was common (n=22).

CONCLUSIONS

RSV is common pathogen of ARI in children from Suzhou. RSV viral activity peaks during winter and spring. The children at age of less than 1 year are susceptible to RSV. hMPV is also an important pathogen of ARI, with a peak detection rate between March and May. Mixed viral infection is common in children less than 1 year old.

More vaccine efficacy studies on the recombinant Bacille Calmette-Guerin co-expressing Ag85B, Mpt64 and Mtb8.4

The immunogenicity of the recombinant Bacille Calmette-Guerin: rBCG-Ag85B-Mpt64(190-198)-Mtb8.4 (rBCG-AMM) was evaluated in our previous study. This paper compares the protective efficacy of rBCG-AMM, rBCG-A which overexpresses Ag85B and BCG in C57BL/6 mice. There was no significant difference in proliferation characteristics among rBCG-AMM, rBCG-A and BCG. The growth characteristics of rBCG-AMM in host tissue were identical to control BCG, suggesting the improved protective efficacy was directly related to the expression of the Ag85B-Mpt64(190-198)-Mtb8.4 fusion protein. The protective experiment demonstrated that rBCG-AMM could confer similar or even better protective efficacy against Mycobacterium tuberculosis infection compared with BCG or rBCG-A as evaluated by bacterial organ loads, lung histopathology and net weight gain or loss. The results suggested that the recombinant BCG: rBCG-Ag85B-Mpt64(190-198)-Mtb8.4 is a potential vaccine candidate for further study.

Nature of amine-surfactant interactions at the air-solution interface

The surface tension and adsorption behavior of polymer/surfactant mixtures of polyethyleneimine (PEI)/sodium dodecyl sulfate (SDS) is strongly dependent on pH. At both low and high pH, a strong PEI/SDS interaction gives rise to surface polymer/surfactant complex formation that results in significantly enhanced SDS adsorption at very low SDS concentrations and in multilayer formation at the interface. At low pH, this strong PEI/SDS interaction is dominated by the electrostatic attraction between the two oppositely charged species. However, at high pH the PEI is essentially neutral, and the origin of the "hydrophobic" interaction, or interaction of nonelectrostatic origin, is less clear. To investigate the origins of this interaction further, we have used neutron reflectivity and surface tension to study the pH dependence of the surface adsorption of different anionic surfactants-SDS, lithium dodecyl sulfate (LiDS), and sodium dodecyl benzene sulfonate (LAS)--in the presence of a range of small amine molecules (from ethylenediamine to pentaethylenehexamine). Analogous to that observed in PEI/SDS mixtures, the presence of amine molecules induces a strong enhancement in the surfactant adsorption at both low and high pH, which can result in extreme cases in multilayer formation at the interface. At high pH, the adsorption is highly dependent upon the amine molecular weight and is equivalent to that observed at low pH by the time the molecular weight of the amine has increased to that of pentaethylenehexamine. We attribute this nonelectrostatic interaction observed at high pH to the combined effect of a dipole-dipole interaction between the sulfate (or sulfonate) headgroup and the amine nitrogens and a cooperative hydrophobic interaction between the chains of the attached surfactants. At high pH and when there are at least six amine groups present, this effect appears to be equivalent in strength to the electrostatic attraction that dominates at low pH. These results are significant in the context of understanding the unusual nature of the PEI/surfactant interaction and of using small molecular weight additives rather than much larger molecular weight polymers to manipulate adsorption properties.

Minimally invasive total hip arthroplasty: a systematic review

The purpose of this study was to compare the operative outcome between mini and standard incisions in total hip arthroplasty (THA). We identified 12 randomised or quasi-randomised control trials (RCT or qRCT) published between 1996 and 2008. Subgroup and sensitivity analyses were performed to evaluate the differences in results for surgical approach, trial quality, and follow-up duration. Operative time and blood loss were significantly reduced in the mini-incision group for studies with the posterior or posterolateral approach. Concerning postoperative complications, there were no significant differences between the two groups with no significant heterogeneity. No differences were observed between the two groups for Harris hip score and radiographic results except for cup anterversion. Although mini-incision appeared to have similar outcomes compared to standard incision, the follow-up is short-term according to current standards in THA. High-quality studies are required to compare the outcomes of these two procedures.

Role of TLR4 for paclitaxel chemotherapy in human epithelial ovarian cancer cells

BACKGROUND

Paclitaxel has been reported to be a ligand to Toll like receptor 4 (TLR4). Myeloid differentiation factor 88(MyD88) was described as a myeloid differentiation primary response gene. TLR4 signalling owns two pathways: MyD88-dependent and MyD88-independent pathways. XIAP is a key member of the inhibitor of apoptosis protein family. Akt is a major downstream target of growth factor receptor tyrosine kinases, which negatively regulates apoptotic pathways through phosphorylation (pAkt). The aim of the present study is to investigate the role of TLR4 in paclitaxel resistance of ovarian cancer cells.

MATERIALS AND METHODS

We reconstructed the RNA interference expression vector, pGenesil-1-U6 specifically targeting TLR4 mRNA, which was stable transfected into the human ovarian cancer cell line SKOV3 (MyD88-positive expression) and A2780 (MyD88-negative expression). Cell proliferation, cell cycle distribution and cell apoptosis were assessed in the cells transfected with scramble control shRNA (SKOV3/shControl, A2780/shControl) and TLR4 shRNA (SKOV3/shTLR4, A2780/shTLR4) to explore the possible functions of TLR4 in ovarian cancer cells growth. The expression of TLR4, MyD88, XIAP, Akt and pAkt was analysed by Western blot analysis.

RESULTS

A knockdown of TLR4 levels down-regulated the expression of XIAP and pAkt. And it restored the inhibitory effect of paclitaxel on cell proliferation and impeding cell cycle progression in SKOV3 cells.

CONCLUSIONS

It suggests that TLR4 negatively regulates paclitaxel chemotherapy and MyD88 is an essential downstream factor to TLR4 signalling for this resistance. Knockdown of TLR4 induces paclitaxel chemosensitivity which might depress the Akt pathway. The TLR4-MyD88 signalling represents an important source to promote tumour growth.

Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) monitored by tree bark in an E-waste recycling area

To investigate the environmental levels and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), tree bark samples (n=22) were collected from Luqiao, an E-waste recycling area, in east China in July 11-13, 2006. The average concentrations of PCDD/Fs, PBDEs, and PCBs determined by isotope dilution-high resolution gas chromatography (HRGC) coupled with high resolution mass spectrometer (HRMS) were 0.1+/-0.0, 1.4+/-0.2, and 6.5+/-0.8 microg g(-1) lipid weight, respectively. PCDD/F-toxic equivalent (TEQ, WHO-1998), PCB-TEQs, and total dioxin-like TEQs were 1.3+/-0.1, 0.5+/-0.0, and 1.8+/-0.2 ng g(-1) lipid weight, respectively. The profiles of these pollutants in the tree bark were also discussed. Tetra-CDFs, deca-BDE and tri-CBs were the main homologues and accounted for 47% of total PCDD/Fs, 79.3% of total PBDEs, and 33.2% of total PCBs, respectively; As for TEQs, 2,3,4,7,8-PeCDF and PCB126 were the main contributors and accounted for 36% of the total PCDD/F-TEQs and 81.2% of the total PCB-TEQs, respectively. High accumulation of PCDD/Fs, PBDEs, and PCBs detected in the tree bark indicated heavy contaminations of these pollutants in Luqiao area.

Experimental study on air-stream gasification of biomass micron fuel (BMF) in a cyclone gasifier

Based on biomass micron fuel (BMF) with particle size of less than 250 microm, a cyclone gasifier concept has been considered in our laboratory for biomass gasification. The concept combines and integrates partial oxidation, fast pyrolysis, gasification, and tar cracking, as well as a shift reaction, with the purpose of producing a high quality of gas. In this paper, experiments of BMF air-stream gasification were carried out by the gasifier, with energy for BMF gasification produced by partial combustion of BMF within the gasifier using a hypostoichiometric amount of air. The effects of ER (0.22-0.37) and S/B (0.15-0.59) and biomass particle size on the performances of BMF gasification and the gasification temperature were studied. Under the experimental conditions, the temperature, gas yields, LHV of the gas fuel, carbon conversion efficiency, stream decomposition and gasification efficiency varied in the range of 586-845 degrees C, 1.42-2.21 N m(3)/kg biomass, 3806-4921 kJ/m(3), 54.44%-85.45%, 37.98%-70.72%, and 36.35%-56.55%, respectively. The experimental results showed that the gasification performance was best with ER being 3.7 and S/B being 0.31 and smaller particle, as well as H(2)-content. And the BMF gasification by air and low temperature stream in the cyclone gasifier with the energy self-sufficiency is reliable.

Observation of an ultracold plasma instability

We present the first observation of an instability in an expanding ultracold plasma. We observe periodic emission of electrons from an ultracold plasma in weak, crossed magnetic and electric fields, and a strongly perturbed electron density distribution in electron time-of-flight projection images. We identify this instability as a high-frequency electron drift instability due to the coupling between the electron drift wave and electron cyclotron harmonic, which has large wave numbers corresponding to wavelengths close to the electron gyroradius.

Ultracold plasma expansion in a magnetic field

We measure the expansion of an ultracold plasma across the field lines of a uniform magnetic field. We image the ion distribution by extracting the ions with a high-voltage pulse onto a position-sensitive detector. Early in the lifetime of the plasma (<20 micros), the size of the image is dominated by the time-of-flight Coulomb explosion of the dense ion cloud. For later times, we measure the 2D Gaussian width of the ion image, obtaining the transverse expansion velocity as a function of the magnetic field (up to 70 G). We observe that the expansion velocity scales as B(-1/2), explained by a nonlinear ambipolar diffusion model with anisotropic diffusion in two different directions.

Factors associated with errors in self-reported height and weight in older adults

OBJECTIVES

Describe the distribution and direction of self-reported versus measured height and weight using variables associated with aging such as cognition, health status, age, and bone mineral density (BMD), and examine the effect of these measurement differences on body mass index (BMI) classification.

DESIGN

Data was derived from the third National Health and Nutrition Examination Survey (NHANESIII) conducted from 1988-1994, a nationwide probability sample.

PARTICIPANTS

4,590 non-institutionalized older adults aged 60 and older.

MEASUREMENTS

Self-reported and measured height and weight, demographic and lifestyle characteristics, BMD, and subscales from the Mini Mental State Exam were used. Values were considered correct if self-reported height was within one inch of measured height, self-reported weight was within 5 lbs of measured weight, and self-reported BMI was within the same classification as measured BMI.

RESULTS

Over-reported height increased with age in both men and women, occurring in 70% of those aged 80 and older. Compared to people with normal BMD, a significantly higher proportion of osteoporotic men (76% versus 47%, P<0.001) and women (52% versus 35%, P<0.001) over-reported their height. Additionally, significant misclassifications of self-reported height and weight occurred among people in poor health and those with poor performances on memory and calculation tests. Nevertheless, there was agreement in BMI classification among almost 80% of the population and among 90% of individuals in the healthy BMI category.

CONCLUSION

This study suggests that among an older population, self-reported height and weight may be strongly related to age-associated changes in health status, cognition and BMD.

Using three-body recombination to extract electron temperatures of ultracold plasmas

Three-body recombination, an important collisional process in plasmas, increases dramatically at low electron temperatures, with an accepted scaling of Te(-9/2). We measure three-body recombination in an ultracold neutral xenon plasma by detecting recombination-created Rydberg atoms using a microwave-ionization technique. With the accepted theory (expected to be applicable for weakly coupled plasmas) and our measured rates, we extract the plasma temperatures, which are in reasonable agreement with previous measurements early in the plasma lifetime. The resulting electron temperatures indicate that the plasma continues to cool to temperatures below 1 K.

An optimized mini-preparation method to obtain high-quality genomic DNA from mature leaves of sunflower

In order to investigate the mutation characteristics and to further examine the genetic variation of mutant sunflower (Helianthus annuus) obtained in plants grown from seeds exposed to space conditions, only the mature tissues such as leaf and flower could be used for DNA extraction after mutation characteristics were confirmed. The rich contents of polysaccharides, tannins, secondary metabolites, and polyphenolics made it difficult to isolate high-quality DNA from mature leaves of sunflower according to previous reports. Based on the comparison of the differences in previously reported protocols, a modified method for the extraction of high-quality DNA was developed. Using this protocol, the DNA isolated from sunflower was high in quality and suitable for restriction digestion (EcoRI, HindII, BamHI), random amplified polymorphic DNA study and further molecular research. Therefore, the modified protocol was suitable for investigating the genetic variation of sunflower using mature leaf DNA.

Identification of Avai polymorphisms in the third intron of GH gene and their associations with abdominal fat in chickens

Growth hormone (GH) plays a diverse role in animals together with other hormones of somatotropic axis. In the current research, chicken GH (cGH) as a candidate gene affecting carcass traits was investigated in the chickens from 2 local chicken breeds [Mountainous Black-Bone (Wugu) and Caoke chicken] in the Sichuan province, 1 pure line of a quality chicken (Sanhuang chicken) from the Guangdong province, and commercial crossbreds. The RFLP method was used to identify polymorphisms of the cGH gene. Three restriction enzyme polymorphic sites were detected in the cGH gene. Sequence alignment from GenBank revealed 2 mutations in the third intron of the cGH gene, which were identified by the AvaI enzyme. Two novel AvaI polymorphic sites were genotyped in 240 chickens from the above-mentioned chicken populations. One EcoRV polymorphic site, the previously reported polymorphism, was also detected in these populations. Significant differences in allelic and genotypic frequencies among all the chicken populations were observed. In AvaI polymorphic sites, allele A2 and B1 had higher frequencies than allele A1 and B2, respectively. In EcoRV polymorphic sites, the frequency of allele N2 was higher than that of allele N1. Associations of polymorphisms of the cGH gene with carcass traits were analyzed by using a GLM procedure. Significant associations were found between AvaI genotypes or combined genotypes and abdominal fat weight and abdominal fat percentage (P<or=0.05). The allele A2 and B1 had a beneficial effect on increasing the live BW, breast muscle weight, and breast muscle percentage while decreasing the abdominal fat weight, abdominal fat percentage, and s.c. fat thickness. No significant associations were observed between EcoRV genotypes and carcass traits. In conclusion, the cGH gene may be a potential marker affecting the abdominal fat trait of chickens.

The impact of electrolyte on the adsorption of sodium dodecyl sulfate/polyethyleneimine complexes at the air-solution interface

The addition of electrolyte (0.1 M NaCl) is shown to have a significant impact upon the surfactant concentration and solution pH dependence of the adsorption of sodium dodecyl sulfate (SDS)/polyethyleneimine (PEI) complexes at the air-solution interface. Substantial adsorption is observed over a wide surfactant concentration range (from 10(-6) to 10(-)2 M), and over much of that range of concentrations the adsorption is characterized by the formation of surface multilayers. The surface multilayer formation is most pronounced at high pH and for PEI with a lower molecular weight of 2K, compared to the higher molecular weight of 25K. These results, obtained from a combination of neutron reflectivity and surface tension, highlight the substantial enhancement in surfactant adsorption achieved by the addition of a combination of the polyelectrolyte, PEI, and a simple electrolyte. Furthermore the effect of electrolyte on the pH dependence of the adsorption further highlights the importance of the hydrophobic interaction in surface surfactant/polyelectrolyte complex formation.

The interaction between sodium alkyl sulfate surfactants and the oppositely charged polyelectrolyte, polyDMDAAC, at the air-water interface: the role of alkyl chain length and electrolyte and comparison with theoretical predictions

The effect of alkyl chain length and electrolyte on the adsorption of sodium alkyl sulfate surfactants and the oppositely charged polyelectrolyte, polyDMDAAC, at the air-water interface has been investigated by surface tension and neutron reflectivity. The variations in the patterns of adsorption and surface tension behavior with alkyl chain length and electrolyte are discussed in the context of the competition between the formation of surface active surfactant/polyelectrolyte complexes and polyelectrolyte/surfactant micelle complexes in solution. A theoretical approach based on the law of mass action has been used to predict the surface effects arising from the competition between the formation of polyelectrolyte/surfactant surface and solution complexes and the formation of free surfactant micelles. This relatively straightforward model is shown to reproduce the principal features of the experimental results.

Exposure of traffic police to Polycyclic aromatic hydrocarbons in Beijing, China

Exposure of on-duty traffic police in Beijing to polycyclic aromatic hydrocarbons (PAHs) was investigated during the summer, 2004 using a personal sampling technique in measuring both particulate and gaseous phase PAHs. The results were then compared with those from two control sites away from the street. Exposure levels to gaseous and particulate PAHs for the traffic police were found to be 1525 +/- 759 ngm(-3) and 148 +/- 118 ngm(-3), respectively, representing 2-2.5 times higher levels than those at the control sites. The daily inhalation exposure of the police was estimated to be 277 ngkg(-1)d(-1). Most of the PAHs exposure came from the vapor phase, particularly NAP, FLO and PHE. Based on calculated PAH diagnostic ratios, the major source of PAHs exposure was from vehicle exhaust. The effects of temperature, humidity and atmospheric stability on exposure levels are also discussed.

Assessment of soil lead exposure in children in Shenyang, China

Soil lead pollution is serious in Shenyang, China. The paper brings together the soil work, the bioaccessibility, and the blood lead data to assess the soil lead exposure in children in Shenyang, China. Approximately 15.25% of the samples were above China Environment Protection Agency guideline concentration for soil Pb to protect human from health risk (350 mgkg(-1)). Pb concentrations varied among use scenarios. The main lead contamination sources are industry emission and automobile exhaust. Bioaccessibility also varied among use scenarios. Children, who ingested soil from industrial area, public parks, kindergarten playground, and commercial area, are more susceptible to soil lead toxicity. The industrial area soil samples presented higher bioaccessibility compared to the other use scenario soil samples contaminated by automobile exhaust. The result also suggested a most significant linear relationship between the level of Pb contamination and the amount of Pb mobilized from soil into ingestion juice. Soil pH seemed to have insignificant influence on bioaccessibility in the present study. Bioaccessibility was mainly controlled by other factors that are not investigated in this study. A linear relationship between children blood lead and soil intestinal bioaccessibility was present in the study. Children who are 4-5 years old are more likely to demonstrate the significant relationship between soil lead bioaccessibility and blood lead as their behaviors place them at greatest risk of soil lead toxicity, and their blood lead levels are more likely to represent recent exposure.

A novel method for analysis of single ion channel signal based on wavelet transform

A single ion channel signal was analysed by the power distribution fraction constructed by a discrete wavelet transform. Average opening time and energy distribution of the signal can be obtained directly by this method. The method can also be used when the signal is corrupted by noise. By contrast, the conventional frequency domain analysis method--power spectral density--is less effective. Power distribution fraction will therefore give more useful information in analysis of experimental ion channel signals, principally by giving values of the mean channel opening time. The method may be applied to distinguish different ion channels more efficiently and to find their reactions to drugs.