Search

Fouling of surfaces remains one of the largest challenges in the field of water filtration. Electrically conductive surfaces have shown antifouling capabilities under organic foulants. Additionally, two-dimensional nanomaterials—e.g., graphene oxide (GO), reduced graphene oxide (rGO) and molybdenum disulfide (MoS2)—have antifouling properties and can be used to modify conductive polymer surfaces for the mitigation of fouling. Here, the surface attachment of foulants was investigated as a function of the surface charge by applying an external voltage. The release behavior of deposited foulants from polypyrrole surfaces modified with GO (GO-PPy), rGO-2h (rGO-PPy) and MoS2 (MoS2-PPy) was also studied. An electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) was used for attachment and release studies of the foulants during external voltage application. Bovine serum albumin (BSA) was used as a model protein foulant in this study. Results show that it was possible to delay the attachment of the BSA foulant (more than 75%) on rGO-PPy and MoS2-PPy surfaces upon the application of −0.5 VAg/AgCl due to the electrostatic repulsion created by the external negative voltage on the surface. Moreover, the BSA attachment rate slows down by 92% and 91% on the rGO-PPy and MoS2-PPy surfaces compared to the bare PPy surface under the no voltage condition. Conversely, applying a voltage of +0.5 VAg/AgCl was not effective in delaying the attachment of BSA due to the presence of positively charged areas on the BSA surface. During the release study, it was found that it is possible to release the deposited BSA from all of the surfaces by NaCl electrolysis upon application of a voltage of +0.74 VAg/AgCl. Continuous generation of free chlorine (HOCl and OCl−) due to the oxidizing current produced on PPy and functionalized surfaces during external voltage application accelerates the degradation of the deposited BSA, resulting in the release of the foulant from the surface.

The influence of functional groups on the degradation of graphene oxide nanomaterials under direct sunlight was investigated by systematically varying the surface chemistry. Using a solvothermal reduction process, graphene nanomaterials with varying oxidation levels, including graphene oxide, partially reduced graphene oxide and fully reduced graphene oxide, were prepared. The physical and chemical properties of the nanomaterials were extensively characterized before and after exposure to simulated sunlight. The degradation of the nanomaterials was determined to be directly related to the functional groups present on the basal plane of the graphene nanomaterials. Specifically, the hydroxyl and epoxy functional groups are the most susceptible to photodegradation. Upon sunlight exposure, the amount of oxygen-containing functional groups on all graphene nanomaterials decreases over time, with fully reduced graphene oxide showing the lowest degradation rate due to the presence of fewer reactive functional groups on the surface. Overall, these results suggest that the oxygen-containing functional groups on the basal plane are the major initiators of the photodegradation of graphene nanomaterials.

Aims Intensity-modulated radiotherapy (IMRT) is increasingly used in the treatment delivery of chemoradiotherapy in anal cancer with the ability to reduce toxicity. We report on 4 year outcomes since the introduction of IMRT and identify the most predictive bowel organ at risk that correlates with acute diarrhoea. Materials and methods Fifty-eight patients receiving definitive chemoradiotherapy for squamous or basaloid cell anal carcinoma (T1-4NanyM0) were reviewed. Fifty-four per cent of patients had stage III disease and most (79%) were treated with a dose of 54 Gy in 30 fractions. Patient acute gastrointestinal toxicity was recorded using Common Terminology Criteria of Adverse Events (CTCAE) diarrhoea grading. Four different methods of bowel were re-contoured for each patient and correlated with acute diarrhoea. Locoregional control and overall survival were analysed. Results CTCAE grade 3 or more diarrhoea occurred in 11/58 patients (19%). Seven patients did not complete treatment; 10 patients (17%) required a treatment break of 3 or more days. ‘Bowel cavity’ was the best predictor of acute grade 3 toxicity using volume (P = 0.002) or volume to bowel cavity in 5 Gy bins (V5–V50Gy); P 300 cm3 predicts a 42% risk. Four year progression-free survival was 84% (95% confidence interval 73–92%) and overall survival was 88% (95% confidence interval 75–95%). Conclusion Chemoradiation using IMRT provides excellent local control and acceptable acute gastrointestinal toxicity. Bowel cavity is the most sensitive predictor for grade 3 versus grade 0–2 diarrhoea, with any volume receiving 5–50 Gy discriminatory.

Hexagonal boron nitride (hBN) is a thermally conductive yet electrically insulating two-dimensional layered nanomaterial that has attracted significant attention as a dielectric for high-performance electronics in addition to playing a central role in thermal management applications. Here, we report a high-content hBN-polymer nanocomposite ink, which can be 3D printed to form mechanically robust, self-supporting constructs. In particular, hBN is dispersed in poly(lactic-co-glycolic acid) and 3D printed at room temperature through an extrusion process to form complex architectures. These constructs can be 3D printed with a composition of up to 60% vol hBN (solids content) while maintaining high mechanical flexibility and stretchability. The presence of hBN within the matrix results in enhanced thermal conductivity (up to 2.1 W K–1 m–1) directly after 3D printing with minimal postprocessing steps, suggesting utility in thermal management applications. Furthermore, the constructs show high levels of cytocomp...

Fouling remains one of the biggest challenges in a myriad of applications such as water filtration, ship hulls, biomedical devices, coating, and painting. Fouling severely hampers the performance and increases the operation and maintenance costs in industries. There is a critical need to develop antifouling surfaces, and two-dimensional (2D) materials, such as graphene oxide (GO) and molybdenum disulfide (MoS2), have shown potential for antifouling surface preparation due to some unique properties. Here, the antifouling properties of these two materials were investigated by observing the deposition kinetics of bacteria and natural organic matter (NOM) using a quartz crystal microbalance with dissipation monitoring (QCM-D). Suwannee River humic acid (SRHA) and E. coli K-12 were used as model NOM and bacteria, respectively. Overall, MoS2 showed slightly better antifouling properties compared to GO. In most cases, the deposition of NOM and E. coli was significantly lower on MoS2 than GO due to the presence of functional groups on GO that bind more easily with the foulants. Deposition of NOM was at least 1.5 times lower on the MoS2 surface than on the GO surface in the presence of both monovalent (Na+) and divalent (Mg2+) cations. However, the presence of 0.5 mM divalent cations (Ca2+, Mg2+) with NOM reduced the antifouling properties of both MoS2 and GO by a factor of ≥1.5 due to a salt bridging effect and reduced energy barrier.

Fouling remains a major challenge for the longevity of filtration membranes and their application in membrane-based treatment facilities. Polymers, such as polysulfone (Psf) and polyamide (PA) that are used as commercial and laboratory ultrafiltration and nanofiltration membranes, are prone to severe fouling over the course of their lifetime. In this study, polyethersulfone (PES) membranes were coated with two-dimensional nanomaterials, including graphene oxide (GO), reduced graphene oxide (rGO), and molybdenum disulfide (MoS2). The effect of the nanosheets on the pressure-driven water transport and antifouling performance of the modified membranes was investigated in terms of water permeability, initial flux decline under simulated fouling condition, and flux recovery ratio (FRR). The GO functionalized membrane significantly impedes water transport due to the side-pinning effect of functional groups. 32% reduction in C–O and 35% reduction in overall oxygen content of GO by reducing thermally it to rGO, restored the permeability by 300%. However, despite the higher initial water flux, the rGO functionalized membranes were still more prone to fouling than GO due to the increase in hydrophobicity. Conversely, MoS2 nanosheets with no functional groups offer a frictionless water flow through nanochannels. The smooth MoS2/PES membrane showed better antifouling performance than both the GO and rGO functionalized membranes while providing 3.7 times faster water transport.

The aggregation and stability of graphene oxide (GO) and three successively reduced GO (rGO) nanomaterials were investigated. Reduced GO species were partially reduced GO (rGO-1h), intermediately reduced GO (rGO-2h), and fully reduced GO (rGO-5h). Specifically, influence of pH, ionic strength, ion valence, and presence of natural organic matter (NOM) were studied. Results show that stability of GO in water decreases with successive reduction of functional groups, with pH having the greatest influence on rGO stability. Stability is also dependent on ion valence and the concentration of surface functional groups. While pH did not noticeably affect stability of GO in the presence of 10 mM NaCl, adding 0.1 mM CaCl2 reduced stability of GO with increased pH. This is due to adsorption of Ca(2+) ions on the surface functional groups of GO which reduces the surface charge of GO. As the concentration of rGO functional groups decreased, so did the influence of Ca(2+) ions on rGO stability. Critical coagulation concentrations (CCC) of GO, rGO-1h, and rGO-2h were determined to be ∼ 200 mM, 35 mM, and 30 mM NaCl, respectively. In the presence of CaCl2, CCC values of GO and rGO are quite similar, however. Long-term studies show that a significant amount of rGO-1h and rGO-2h remain stable in Call's Creek surface water, while effluent wastewater readily destabilizes rGO. In the presence NOM and divalent cations (Ca(2+), Mg(2+)), GO aggregates settle from suspension due to GO functional group bridging with NOM and divalent ions. However, rGO-1h and rGO-2h remain suspended due to their lower functional group concentration and resultant reduced NOM-divalent cation bridging. Overall, pH, divalent cations, and NOM can play complex roles in the fate of rGO and GO.

Research and development of two-dimensional transition metal dichalcogenides (TMDC) (e.g., molybdenum disulfide [MoS2]) in electronic, optical, and catalytic applications has been growing rapidly. However, there is little known regarding the behavior of these particles once released into aquatic environments. Therefore, an in-depth study regarding the fate and transport of two popular types of MoS2 nanomaterials, lithiated (MoS2-Li) and Pluronic PF-87 dispersed (MoS2-PL), was conducted in saturated porous media (quartz sand) to identify which form would be least mobile in aquatic environments. The electrokinetic properties and hydrodynamic diameters of MoS2 as a function of ionic strength and pH were determined using a zeta potential analyzer and dynamic light scattering techniques. Results suggest that the stability is significantly decreased beginning at 10 and 31.6 mM KCl, for MoS2-PL and MoS2-Li, respectively. Transport study results from breakthrough curves, column dissections, and release experiments suggest that MoS2-PL exhibits a greater affinity to be irreversibly bound to quartz surfaces as compared with the MoS2-Li at a similar ionic strength. Derjaguin–Landau–Verwey–Overbeek theory was used to help explain the unique interactions between the MoS2-PL and MoS2-Li surfaces between particles and with the quartz collectors. Overall, the results suggest that the fate and transport of MoS2 is dependent on the type of MoS2 that enters the environment, where MoS2-PL will be least mobile and more likely be deposited in porous media from pluronic–quartz interactions, whereas MoS2-Li will travel greater distances and have a greater tendency to be remobilized in sand columns.

Carbon nanotubes (CNTs) exhibit a number of physicochemical properties that contribute to adverse biological outcomes. However, it is difficult to define the independent contribution of individual properties without purified materials. A library of highly purified single-walled carbon nanotubes (SWCNTs) of different lengths is prepared from the same base material by density gradient ultracentrifugation, designated as short (318 nm), medium (789 nm), and long (1215 nm) SWCNTs. In vitro screening shows length-dependent interleukin-1β (IL-1β) production, in order of long > medium > short. However, there are no differences in transforming growth factor-β1 production in BEAS-2B cells. Oropharyngeal aspiration shows that all the SWCNTs induce profibrogenic effects in mouse lung at 21 d postexposure, but there are no differences between tube lengths. In contrast, these SWCNTs demonstrate length-dependent antibacterial effects on Escherichia coli, with the long SWCNT exerting stronger effects than the medium or short tubes. These effects are reduced by Pluronic F108 coating or supplementing with glucose. The data show length-dependent effects on proinflammatory response in macrophage cell line and antibacterial effects, but not on collagen deposition in the lung. These data demonstrate that over the length scale tested, the biological response to highly purified SWCNTs is dependent on the complexity of the nano/bio interface.

On August 31, 2009, Judge Stein of the Southern District of New York granted defendant Citigroup’s motion to dismiss a complaint for breach of fiduciary duty filed by participants in Citigroup’s 401(k) plans. The action sought to recover plan losses suffered as a result of Citigroup stock’s staggering losses. Judge Stein dismissed the action after concluding that the plans’ trustees were “immune from judicial inquiry” in connection with the plans’ investments in Citigroup stock. Judge Stein’s decision conferring judicial immunity on plan fiduciaries appears contrary to ERISA, departs from relevant precedent and curtails rigorous protections afforded to retirement savings. If upheld, this rule will effectively bar most actions against fiduciaries concerning plan investments in company stock.

Colorectal cancer (CRC) has the second highest mortality rate of all cancers in Ireland. Developments in imaging, surgical technique, and perioperative care in the last two decades have altered management.To determine whether outcome following surgery for CRC in the mid-west has changed over a 22-year period.Four hundred and twenty-two patients were divided into two time periods: Group A (1980-1991, n = 203) and Group B (1992-2002, n = 219) and demographic, inpatient, and survival data were reviewed.The mean age was 67 years, 59% were male. Group B patients had less advanced disease at presentation (Dukes' stage D 14% vs 22%, p0.05), fewer perioperative complications (13% vs 23%, p0.05), and fewer local recurrences (6.8% vs 11.8%, p0.05) than Group A. No difference in 30-day mortality rate or survival was detected.Although perioperative CRC management has improved, methods of earlier diagnosis and improvements in adjuvant therapy should be explored to improve survival.

The purpose of this correlational study was to examine the relationship between body satisfaction and self-concept in elementary school children. Participants were twentythree boys and twenty-eight girls from the third and sixth grades of a rural public school. Demographic information, body satisfaction scores, self-concept scores, and measures of parental attitudes were obtained from the participants through a questionnaire. It was hypothesized that body satisfaction and self-concept would be related in elementary school children. It was expected that this relationship would be impacted by grade, sex, and parental attitudes. A significant relationship existed between body satisfaction and self-concept in girls, but not boys. No grade differences were detected in the relationship. Body satisfaction was significantly correlated with body criticism from peers among sixth graders. A parent's body satisfaction appeared to be a significant predictor of the body satisfaction of his/her opposite sex child for both third — and sixth-graders.

Design methodology management is an emerging technology in the world of electrical computer aided design. It has spawned considerable research over the past decade, and a firm belief in many people's minds that it is the key to significant productivity enhancements in the next. How close are we to seeing this belief fulfilled? In this paper, we define the concepts that are important to design methodology management systems and explain how these systems relate to CAD frameworks. We then examine and characterize 23 notable design methodology management systems of the last 15 years in order to understand the state of the art. Finally, we describe and analyze the trends we have seen in these systems and propose where this technology is headed. >

Purpose: Blood loss and high rates of transfusion in the intensive care unit and burn centre is an area of ongoing concern. Many studies report that patients receiving red blood cell transfusions in the ICU/burn centre setting are more likely to experience complications. Blood use brings the risk of infection, adverse reaction and immunosuppression and more recently evidence for tumour progression. The purpose of this study was to review blood transfusion practices in burns patients attending the national burn centre over a 2 year period and to assess transfusion policies over this timeframe. Methodology: A retrospective chart review from 2006 to 2008 was performed. All patients with >10% total body surface area burns who underwent surgery were included in the study. Variables examined were packed red blood cells transfused during and after surgery, preoperative and postoperative haemoglobin and cross-match to transfusion ratios. Results: Of the 146 patients reviewed, 79 required multiple transfusions which were administered in the majority of cases via a traditional red blood cell transfusion approach. There was a high cross-match to transfusion ratio. Conclusion: A traditional blood transfusion policy is administered in this unit however in those patients that were treated using a more restrictive policy, a lower haemoglobin was well tolerated. There is scope for the implementation of a more restrictive transfusion policy.

A study was performed to determine the frequency and antimicrobial susceptibility of Enterococcus species in clinical specimens. Of 943 aesculin-positive isolates, 873 (92%) were identified as enterococci (737 Enterococcus faecalis, 129 Enterococcus faecium and 7 other Enterococcus species). High-level resistance to gentamicin was found in 15.2% of Enterococcus faecalis, but not in Enterococcus faecium; 58% of Enterococcus faecium were resistant to gentamicin at a concentration of 64 mg/l. None of the isolates were shown to possess vancomycin resistance.