Studies on the sulfation of cellulose α-lipoate and ability of the sulfated product to stabilize colloidal suspensions of gold nanoparticles

© 2015 Elsevier Ltd. A versatile method for the synthesis of cellulose α-lipoate with a low degree of substitution (DS) has been developed using N,N-dimethylacetamide (DMA)/LiCl as a solvent and N,N′-carbonyldiimidazole (CDI) as an esterification reagent. The cellulose α-lipoate with DS of α-lipoate groups of 0.26 was converted with sulfur trioxide-pyridine complex in dimethyl sulfoxide (DMSO) as solvent. The sulfation is accompanied by an unexpected partial oxidation of the disulfide moiety leading to the formation of the corresponding stereoisomers of S-oxides. The resulting mixture of water-soluble cellulose α- and β-lipoate sulfate possesses a DS of sulfuric acid half ester groups of 1.78. This cellulose-α/β-lipoate sulfate derivative can be used as an effective stabilizer and solubilizer for the formation of colloidal suspensions of gold nanoparticles formed in situ in aqueous solution

Onset of giant planet migration before 4480 million years ago

Immediately after their formation, the terrestrial planets experienced intense impact bombardment by comets, leftover planetesimals from primary accretion, and asteroids. This temporal interval in solar system evolution, termed late accretion, thermally and chemically modified solid planetary surfaces and may have impeded the emergence of life on the Hadean Earth. The sources and tempo of late accretion are, however, vague. Here, we present a timeline that relates variably retentive radiometric ages from asteroidal meteorites, to new dynamical models of late accretion that invokes giant planet migration. Reconciliation of the geochronological data with dynamical models shows that giant planet migration immediately leads to an intense 30 Myr influx of comets to the entire solar system. The absence of whole-sale crustal reset ages after 4450 Ma for the most resilient chronometers from Earth, Moon, Mars, Vesta and various meteorite parent bodies confines the onset of giant planet migration to no later than ca. 4480 Ma. Waning impacts from planetesimals, asteroids (and a minor cometary component) continue to strike the inner planets through a protracted monotonic decline in impactor flux; this is in agreement with predictions from crater chronology. Amended global 3-D thermal analytical bombardment models derived from our new impact mass-production functions show that persistent niches for prebiotic chemistry on the early Hadean Earth could endure late accretion for at least the last 4400 Myr.Comment: Main text: 46564 characters with spaces/7549 words Tables: 3 Figures:7 References: 11

Judicial Development of Standards of Liability in Government Enforcement Actions under the Comprehensive Environmental Response, Compensation and Liability Act

The Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) represents the first major attempt on a national level to address the problem of abandoned hazardous waste sites. CERCLA permits an action to be brought in federal court for recovery of amounts disbursed from the Superfund against, inter alia, any person who arranges for treatment or disposal of wastes at a site, typically the generator of the hazardous wastes. CERCLA\u27s enforcement provisions contain numerous ambiguities and apparent inconsistencies on issues that directly affect the potential liability of CERCLA\u27s defendants. Many of the inadequacies probably can be traced to the last-minute compromise which led to the passage of the statute. The net effect of inadequate drafting and consideration of Superfund legislation is that the task of forging meaningful standards for liability under the final product is left largely to the courts. This Article discusses the significant legal issues which arise in government enforcement actions regarding the imposition of liability under CERCLA, and examines the role that courts have played in developing applicable standards of liability. This Article also examines the state of the law in the context of two common scenarios: (a) actions under section 107 of CERCLA for recovery of costs of response at a hazardous waste site; and (b) actions under section 106 of CERCLA for injunctive relief. Finally, this Article addresses: (1) who may be held liable; (2) under what conditions liability may arise; (3) what standard for liability exists; and (4) the extent of potential liability

Judicial Development of Standards of Liability in Government Enforcement Actions under the Comprehensive Environmental Response, Compensation and Liability Act

The Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) represents the first major attempt on a national level to address the problem of abandoned hazardous waste sites. CERCLA permits an action to be brought in federal court for recovery of amounts disbursed from the Superfund against, inter alia, any person who arranges for treatment or disposal of wastes at a site, typically the generator of the hazardous wastes. CERCLA\u27s enforcement provisions contain numerous ambiguities and apparent inconsistencies on issues that directly affect the potential liability of CERCLA\u27s defendants. Many of the inadequacies probably can be traced to the last-minute compromise which led to the passage of the statute. The net effect of inadequate drafting and consideration of Superfund legislation is that the task of forging meaningful standards for liability under the final product is left largely to the courts. This Article discusses the significant legal issues which arise in government enforcement actions regarding the imposition of liability under CERCLA, and examines the role that courts have played in developing applicable standards of liability. This Article also examines the state of the law in the context of two common scenarios: (a) actions under section 107 of CERCLA for recovery of costs of response at a hazardous waste site; and (b) actions under section 106 of CERCLA for injunctive relief. Finally, this Article addresses: (1) who may be held liable; (2) under what conditions liability may arise; (3) what standard for liability exists; and (4) the extent of potential liability

Synergistic antibacterial effects of theaflavin in combination with ampicillin against hospital isolates of Stenotrophomonas Maltophilia

Stenotrophomonas maltophilia is an important opportunistic nosocomial pathogen that shows intrinsic resistance to many antibiotics. This often limits treatment options and can cause lengthy hospital stays. Combination treatments are often used to combat resistance and using natural compounds such as polyphenols could give increased treatment options and even the reuse of antibiotics to which high levels of resistance have been observed. A checkerboard assay was used to determine if any synergy exists between ampicillin and the polyphenol theaflavin against 9 clinical isolates and one control isolate (NCTC 13014) of S. maltophilia. It was discovered that significant synergy (P 0.05) does exist between theaflavin and ampicillin, reducing the mean MIC of ampicillin from 12.5-22.9 µg/mL, in liquid culture, to 3.125-6.25 µg/mL. The FIC index was calculated to be 0.22-0.35 confirming synergy. From these results, significant potential for medical applications can be seen and further investigation is recommended

Solution-processed bilayer photovoltaic devices with nematic liquid crystals

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices. © 2013 © 2013 Taylor & Francis

Antifungal synergy of theaflavin and epicatechin combinations against Candida albicans

New antifungal agents are required to compensate for the increase in resistance to standard antifungal agents of Candida albicans, which is an important opportunistic fungal pathogen that causes minor infections in many individuals but very serious infections in those who are immune-compromised. In this study, combinations of theaflavin and epicatechin are investigated as potential antifungal agents and also to establish whether antifungal synergy exists between these two readily accessible and cost-effective polyphenols isolated from black and green tea. The results of disc diffusion assays showed stronger antibacterial activity of theaflavin:epicatechin combinations against C. albicans NCTC 3255 and NCTC 3179, than that of theaflavin alone. Minimum inhibitory concentrations (MICs) of 1,024 μg/ml with theaflavin and 128-256 μg/ml with theaflavin:epicatechin combinations were found. The fractional inhibitory concentration indexes were calculated, and the synergy between theaflavin and epicatechin against both isolates of C. albicans was confirmed. Theaflavin:epicatechin combinations show real potential for future use as a treatment for infections caused by C. albicans

Measles: how many hospitalised cases are we missing?

We aimed to determine whether the Victorian measles surveillance system had missed hospitalised cases of measles during an inter-epidemic period. We searched the Victorian Inpatient Minimum Dataset (VIMD) for the period 1 January 1997 to 30 June 1998 to identify patients with ICD-9 discharge codes for measles (055). The data were compared with that held in the Victorian measles surveillance dataset. The hospital case notes of patients identified in the VIMD but not in the measles surveillance dataset were reviewed systematically to determine whether the patients met case definitions for laboratory-confirmed or clinically compatible measles. Sixteen admissions (15 patients) were identified with a measles ICD-9 code. Eight patients were not identified in the measles surveillance dataset. Of these, one was a laboratory confirmed case of measles and two met a clinical case definition but all should have been notified to the Department of Human Services as suspected cases. While the small number of missed notifications is encouraging in terms of overall measles surveillance, it highlights important deficiencies in the awareness of hospital staff of their role in the control of measles, particularly as Australia moves towards the elimination of measles

Whiter, brighter, and more stable cellulose paper coated with antibacterial carboxymethyl starch stabilized ZnO nanoparticles

Small, carboxymethyl-starch-stabilised zinc oxide nanoparticles with a defined shape, size and morphology were prepared in situ in water at relatively low reaction temperatures using soluble carboxymethyl starch (CMS) as a combined crystallising, stabilising and solubilising agent and triethanolamine as the reducing agent. Aqueous colloidal solutions of these CMS-stabilised ZnO nanoparticles were used to deposit a coating of ZnO nanoparticles on cellulose paper by a wet-chemistry, polyelectrolyte, layer-by-layer approach using water as the only solvent. Such cellulose paper samples, coated with these CMS-stabilised ZnO nanoparticles, show higher brightness and whiteness than that of blank reference paper and are more stable to UV-radiation than the paper reference as well as demonstrating good antibacterial activity against MRSA and A. baumannii