To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
We present a study of optical and electronic properties of solutions and films based on the fungi-derived pigment xylindein, extracted from decaying wood and processed without and with a simple purification step (“ethanol wash”). The “post-wash” xylindein solutions exhibited considerably lower absorption in the ultraviolet spectral range and dramatically reduced photoluminescence below 600 nm, due to removal of contaminants most likely to be fungal secondary metabolites. The “post-wash” xylindein-based films were characterized by two orders of magnitude higher charge carrier mobilities as compared to “pre-wash” samples. This underlines the importance of minimizing contaminants that disrupt the conductive xylindein network in xylindein-based electronic devices.
The dispute ‘about purification’ between the disciples of John the Baptist and a Jew (John 3.25) has to do with the priority of ethical purity as effected through baptism over the ritual washing prescribed by the Torah, e.g. before entering the Jerusalem temple. This issue is referred to in John 13.10 and 15.3, and also in P.Oxy. 840. It is presupposed here that the circle of Jesus’ disciples received John's baptism of repentance either from John the Baptist or from Jesus (John 3.22, 26; 4.1). The Gospel of John thus engages with an ongoing debate within Jewish Christianity about the obligatory nature of ritual washing.
Bovine κ-casein glycomacropeptide (GMP) found in sweet whey is a 64 amino acid residue glycopeptide, which does not contain phenylalanine or other aromatic amino acids. There is, however, little information available concerning isolation of phenylalanine free GMP from sweet whey. In the study reported in this Research Communication, GMP was purified from three samples of sweet whey protein products (SWPP) by a procedure involving: (1) precipitation of protein by heat treatment; (2) precipitation of protein by pH shift to 4·6; and (3) diethylaminoethyl (DEAE)-Sephacel anion exchange chromatography of soluble portion of each sample obtained after removal of protein precipitates. The total protein precipitated with both heat treatment and pH shift accounted for average 61% of dry weight of SWPP. The GMP fraction obtained by DEAE-Sephacel chromatography accounted for average 7·5% of dry weight of SWPP. Amino acid analysis showed that there was no detectable level of phenylalanine in GMP fractions from all samples examined. The present method may help develop large scale methods of production of GMP.
Stimuli-responsive materials with controlled reversible wettability find diverse application as self-cleaning surfaces, tunable optical lenses and microfluidic devices. We report on an electrochemical approach for dynamic control over the wetting properties of additive-free Cu/CuxO core-shell dendritic structures. By varying the oxidation state of the oxide shell phase, the entire wettability range spanning superhydrophobicity (contact angle > 150°) to superhydrophilicity (contact angle < 10°) can be precisely adjusted in-situ. During the wetting transitions, the surface transforms from a low adhesive rolling state (lotus effect) to high adhesive pinning state (petal effect), and eventually to superhydrophilic state with a water-absorbing ability (fish scale wetting). The wetting alteration is reversible via air-drying at room temperature or mild heat drying at 100°C. The reversibly redox-driven wettability switching is demonstrated for controllable oil-water separation with efficiency higher than 98 percent.
Many researchers are investigating the extreme resilience of bacterial endospores against chemical and physical inactivating agents. The presence of vegetative cells in spore suspensions can result in overly optimistic assessment of inactivating agents; therefore, various spore purification methods have been applied to separate spores from vegetative cells prior to testing. The present study was undertaken to evaluate the effect of two widely used spore purification methodologies on spore integrity and susceptibility to ultraviolet-A (UVA) radiation and free radicals generated from photocatalysts. Bacillus subtilis and Bacillus cereus spores were purified by procedures that involved heat shock alone or chemical washes, lysozyme treatment and heat shock (CLH). The purified spores were exposed to UVA radiation or free radicals generated by photocatalyst and susceptibility were evaluated in terms of survival ratio. The effect of purification procedure on the spore morphology was investigated with electron microscopy. The CLH purification process significantly damages spore coats and increases the susceptibility of Bacillus spores to UVA radiation and photocatalytic inactivation. It is therefore likely that the survival of CLH treated spores in extra-terrestrial environments would be less than that of the same spores purified by a less aggressive procedure.
This article discusses the modeling of liquid flow inside nanotube membranes. Applying known simplifications to the classical fluid model leads to the so-called Hagen–Poiseuille equation, which predicts no flow for diameters up to 1 nm, and very modest flows in nanochannels up to 100 nm. The main feature of classical fluid dynamics that negates the possibility of high flow is the assumption that fluid molecules closest to the channel wall stick to it, the no-slip boundary condition. In the past 10 years, a wealth of experimental evidence has, on the contrary, demonstrated significant water flow in nanotubes with diameters equal to or smaller than 1 nm, opening the possibility of nanotube membranes capable of high flows and fine separation. These high flows have also been observed in molecular dynamics simulations, particularly for water flowing through carbon nanotubes, showing the presence of strong water slip near the walls of the nanotubes. The term “flow enhancement” has been introduced to refer to the ratio of predicted (or measured) flows and the no-slip Hagen–Poiseuille equation. Both experimental and modeling results point to a strong effect on flow enhancement of the interaction between the fluid and the tube’s wall, particularly the wall surface chemistry and structure.
Carbon nanostructures, especially carbon nanotubes and graphene nanopores, have been suggested for use in a wide range of purification and separation applications, from the desalination of seawater to the separation of liquids and gases. However, achieving the required high degree of selectivity among the molecules passing through the pores while maintaining rapid transport is a difficult challenge. Here, we examine the physical mechanisms by which nanopores distinguish between small ions and reject salts while passing water, as examples of how selectivity and purification can be achieved. The simple principles described can be utilized to design novel nanoporous materials for the separation of a wide range of gases, liquids, and solutes.
New computer-controlled, semi-automatic systems were designed and built for CO2 purification and graphitization at the A.E. Lalonde Accelerator Mass Spectrometry (AMS) Laboratory with consideration for user friendliness and high throughput. The stainless steel vacuum lines are orbitally welded to ensure clean seams with low memory. The insulated graphitization ovens with plug-in electrodes provide a hazard-free environment for operators. The closed-loop cooling system circulating low-viscosity Dynalene at –40°C provides highly efficient water trapping. The LabVIEWTM software features (1) pressure and temperature recording for QA/QC; (2) safety interlocks to preclude operator errors resulting in sample loss, cross-contamination, or damaging a vacuum pump; and (3) automation for leak checking, iron conditioning, and running samples. Results from the first year of routinely measured standards, reference, and background materials are reproducible and within acceptance values. In the first year of operation (commissioned in spring 2014), over 1000 targets (~60% unknowns) were produced. With new tube sealing and CO2 purification lines, and two more graphitization lines now operational, the Lalonde AMS Laboratory is able to provide routine radiocarbon analysis (>200 µg carbon) at a capacity of more than 7000 targets per year. Most importantly, the equipment is safe and intuitive, making it ideal for education and training students to run their own samples.
David M. Moffitt has recently put forward an interpretation of Hebrews whereby purification is understood as a victory of life over death, and atonement is effected by the resurrected life of Jesus entering the heavenly sanctuary. We discuss this reading and defend an alternative whereby the moral category of sin is the final target of purification and the notion of ransom, life given in death in place of another life, is key for understanding atonement in Hebrews.
The goal of this work is to study the properties of magnetically aligned CNT/PC nanocomposites towards the development of hydrogen gas separation membranes. A fraction (0.1 weight %) of synthesized carbon nanotubes (CNTs) have been dispersed homogeneously throughout polycarbonate (PC) matrix by ultrasonication. The alignment of CNT in PC matrix has been accomplished by applying an external magnetic field of 1200 Gauss. These nanocomposites have been studied by gas permeation using H2, N2 and Co2 electrical and dielectric constant measurements. Experimental results of gas permeability measurements exhibit here that H2 is more selective than N2 and Co2 in magnetically aligned nanocomposite membranes which can be used as good hydrogen separating media. I-V characteristics show the electron hopping like behavior and dielectric constant shows the enhancement in permittivity of these nanocomposites.
The discovery of graphene based materials has led to significant advancement in several different areas. The large surface area, nanoporous structure and availability of delocalized electron network provide a unique opportunity for purification of solvents via adsorption, absorption or simple trapping. This makes graphene based materials as potential candidates for purification and desalination of water. Here we report synthesis of 3D porous network of oxidized graphene for purification of sea water. The membranes fabricated using these frameworks are hierarchically linked intrinsically defected oxidised graphene sheets by long micro-channels and capable of filtering small ions such as Na+ and Cl-. These are easy to fabricate, reusable and economically viable especially for point of use application. We finally show a fabricated device using membrane made from these 3D networks of oxidized graphene.
An adequate level of personal protective equipment (PPE) is necessary when treating patients with highly infectious diseases or those contaminated with hazardous substances.
Following National Institute for Health Research’s Research Centre (London, United Kingdom) approval, the authors of this study conducted a survey of specialist registrars’ knowledge of the respiratory and skin protection requirements needed during a resuscitation scenario with Advanced Life Support. Participant responses were compared to UK national recommendations and to a previous survey in 2009.
A total of 98 specialist registrars (in Anesthesiology, n=51; in Emergency Medicine (EM), n=21; and in Intensive Care Medicine (ICM) n=26) completed hand-delivered surveys. The best knowledge of PPE requirements (76%) was found for severe acute respiratory syndrome (SARS), with less knowledge about PPE requirements for anthrax, plague, Ebola virus disease (EVD), and smallpox (60%). The results show limited knowledge of PPE requirements (20%-30%) for various chemical warfare agents. Personal protective equipment knowledge regarding treatment of sarin-contaminated casualties was over-rated by 80%, and for patients with EVD, it was over-rated by up to 67% of participants.
The results of the tested cohort indicate that current knowledge regarding PPE for chemical warfare agents remains very limited.
SchumacherJ, BondAR, WoodhamV, BuckinghamA, GarnhamF, BrinkerA. Survey of UK Health Care First Responders’ Knowledge of Personal Protective Equipment Requirements. Prehosp Disaster Med. 2015;30(3):15
A series of fluorine appended highly conjugated fullerenes were prepared containing fluoro-α-cyanostilbene and aryl ester units. These modified PCBM dyads are fully characterized by NMR, Mass spectrometry, UV-vis, and cyclic voltammetry (Figures 1-4). It was found that the presence of fluoro-α-cyanostilbenes and esters affects the cyclic voltammetry and absorption in the UV-Vis region. The PCBA modified fullerenes significantly influences the HOMO-LUMO energy and wide absorption compared to PCBM.
A continuous nonflux inclusion-removal method, rotating gas bubble stirring, is used to purify Mg–10Gd–3Y–0.5Zr melt. The effects of rotating gas bubble stirring process parameters (Ar flow rate, time, and rotating speed) on purifying effectiveness, mechanical properties, and fracture behavior of sand-cast Mg–10Gd–3Y–0.5Zr alloy are studied. The results show that too high or too low Ar flow rate is unfavorable for inclusion-removal. The results also indicate that the high rotary speed of spraying gas is helpful to improve the inclusion-removal and mechanical properties. But when the melt is subjected to overtime gas bubbling treatment, the mechanical properties became poor again. Nonflux purification does not change the microstructure of Mg–10Gd–3Y–0.5Zr alloy. However, rotating gas bubble stirring has a certain effect on the fracture pattern of the alloy. In addition, the melt purifying mechanism of the gas bubble stirring treatment for the sand-cast alloy was discussed systematically.
Single-walled carbon nanotubes (SWCNTs) have attracted significant attention as building blocks for future nanoscale electronics due to their small size and unique electronic properties. However, current SWCNT production techniques generate a mixture of two types of nanotubes with divergent electrical behaviors due to structural variations. Some of the nanotubes act as metallic materials while others display semiconducting properties. This random mixture has prevented the realization of functional carbon nanotube-based nanoelectronics. Here, a method of purifying a continuous flow of semiconducting nanotubes from an initially random mixture of both metallic and semiconducting SWCNTs in suspension is presented. This purification uses A/C dielectrophoresis (DEP), and takes advantage of the large difference of the relative dielectric constants between metallic and semiconducting SWCNTs. Because of a difference in magnitude and opposite directions of a dielectrophoretic force imposed on the random SWCNT solution, metallic SWCNTs deposit onto an electrode while semiconducting SWCNTs remain in suspension . A discussion of these techniques is presented, along with a dielectrophoretic force-utilized microfluidic lab-on-a-chip device that can accomplish purification of semiconducting nanoparticles at high processing rates. The effectiveness of the device is characterized using Raman spectroscopy analysis on separated samples.
Ionic liquids (ILs) are a very interesting new class of fluid materials because of their unique characteristics, such as wide chemical, thermal, and electrochemical stability, high ion conduction, non-detectable vapor pressure, nonflammability, and good-to-excellent capability to dissolve inorganic, organic, and polymer compounds. ILs are proposed for a very wide variety of applications, including electrochemical devices. However, high purity ILs, particularly for high-energy electrochemical applications, are not widely available commercially. In addition, solvent restriction and environmental impact, as well as the possibility to fully recycle chemicals and reagents, represent the most stringent requirements for the future synthesis processes of ILs. This article reviews synthesis route improvements in terms of environment impact solvents, chemical recycling and cost, and process yield for obtaining high purity (below 50 ppm) ILs.
One of the methods to grow nanoscale three-dimensional (3D) Au patterns is to perform local electron-beam-induced deposition (EBID) using the Me2Au(acac) precursor inside the chamber of a scanning electron microscope (SEM). However, due to the organometallic nature of the chemical, the concentration of the metallic constituent in the as-deposited structure is dramatically low, at around 10 at. % of Au. Ex-situ post-annealing of Me2Au(acac) EBIDs is a very promising purification approach, resulting in an Au content of > 92 at. % after annealing at 600 °C. However, in most of the cases it also distorts the geometrical shape of the heat-treated structure, preserving of which is essential for the application. In this paper we present a systematic study of the dependence between the annealing parameters and resulting purity in combination with the shape of the Au structure. Optimized heat treatment conditions for the creation of well-purified high aspect ratio Au pillar array are presented; and for planar continuous structures, the importance of the parameter height to area ratio is identified.
Molten salt flameless oxidation of graphite is one of the prospective methods of irradiated graphite waste processing. Molten salts are capable to retain a considerable part of radionuclides, to neutralize acidic off gases, moreover spent salts could be vitrified on completion of the process. We have used thermodynamic modelling to assess the efficiency of molten salt oxidation of graphite. Equilibrium compositions of both the melt and the off gas were calculated depending on graphite content and temperature. The feasibility of decontaminating the irradiated graphite of its near-surface layers using complete molten salt oxidation was investigated in a series of laboratory experiments. As the molten salt medium used to oxidize irradiated graphite we have investigated lithium, potassium and sodium carbonates. Sodium sulphate, boron oxide, barium and potassium chromates were also used as oxidizers. Tests were carried out at 870–1270 К. The efficiency of decontamination of graphite blocks has been assessed based on the activity of 137Cs and 60Со in the samples before and after molten salt oxidation. Data obtained demonstrated the feasibility of decontamination by molten salt removal of near surface layers on irradiated graphite blocks. Decontamination rate and efficiency depend on oxidizers used and temperature of process.
The Renewable Fuels Standard (RFS) and Energy Independence and Security Act of 2007 (EISA) mandated that 36 billion gallons of biofuels should be blended into transportation fuel by 2022. Implementing this will help reduce greenhouse gas emissions, reduce petroleum imports and encourage the development and expansion of US renewable fuels sector within rural America. Of the 36 billion gallons of biofuels, 16 billion gallons is expected to be from lignocellulosic biomass such as trees and grasses. The Black Hills of South Dakota is rich in ponderosa pine. This feedstock for bioethanol production, which is widely available due to recent pine beetle infestation, will not only add to the RFS requirement, it will also have a positive impact on rural economies in South Dakota. From the wood chips of pine, after acid pretreatment and enzymatic hydrolysis, the fermentable sugars obtained are relatively dilute in concentration (∼20-30 g/L). Hence, within a biorefinery, to increase the fermentation efficiency and decrease downstream processing cost of the biofuels, concentrating the sugars can be beneficial. In this study, Reverse Osmosis (RO) and Nanofiltration (NF) membranes were tested with complex lignocellulosic hydrolysate samples for their ability to concentrate sugars prior to fermentation. Fouling analysis and membrane characterization for both RO and NF membranes were performed by SEM, AFM, BET, contact angle and FTIR spectroscopy. Efficiency of membranes for their ability to separate fermentation inhibitors (e.g., organic and mineral acids, furans and phenolic compounds) from sugars, while simultaneously concentrating the sugars was studied to make the bio-ethanol production process cost and energy efficient. Three commercial nanofiltration membranes GE-R, TS40 and SR100 showed very promising results. GE-R concentrated sugars to more than 2.5 fold in the retentate, and simultaneously separated more than 50% of the inhibitory components into permeate. These results will increase the fermentation efficiency and reduce downstream purification costs of the produced fuel.
Nickel nanoparticles (NNPs) synthesized by a modified polyol method using ethylene glycol as a reducing agent, palladium chloride as a nucleating agent, and polyvinylpyrrolidone (PVP) as a protective agent were investigated as a potential magnetic adsorbent for the purification of hexahistidine-tagged (His6-tagged) recombinant proteins. The synthesis resulted in nanoparticles having an average diameter of 68 ± 28 nm. The x-ray diffraction pattern confirmed the presence of nickel metal, as well as the presence of unreacted nickel (II) hydroxide Ni(OH)2. Magnetic characterization showed that a magnetization saturation of 39.3 electromagnetic unit (emu)/g at 20,000 Oersted (Oe) was reached rapidly and that the material exhibited ferromagnetic behavior. Protein purification results showed that the synthesized NNPs were highly selective for binding to a His6-tagged recombinant protein single-domain antibody ToxA5.1. In addition, NNPs were used for four adsorption cycles without significant binding capacity losses. These particles have shown great potential such as being easily synthesized, cost-effective, and highly selective magnetic adsorbents for the purification of His6-tagged recombinant proteins.