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Abstract "Green" electronics represents an emerging area of research aimed at identifying natural materials that are applicable for environmentally safe and biodegradable devices. Iron (Fe) ions are used in gelatin matrixes (gelatin composites) prepared on commercially available flexible paper substrates through the solution method, thus, the "green" electronics were achieved. Although atomic force microscopy images show that fiber-based paper substrates result in rough Al/paper structure surfaces, the uniform interface between top Al electrodes and gelatin composites can be clearly observed in transmission electron microscopy images. This might be due to the gelatin composite acts as not only the resistive layer, but also the smoothing layer. Moreover, Fe ions play an important role in assisting redox reaction or filament formation. An Al/gelatin/Al/paper device has no resistive switching behavior. Meanwhile, devices with Fe ions on a paper substrate show reproducible resistive switching for 18 cycles, an ON/OFF ratio of over 105, and an excellent current distribution (coefficient of variation<60%). The ON/OFF ratio of the device after bending 180 cycles can be maintained at 104. The biodegradable gelatin materials have good ductility and potential in recyclable and green electronic applications. Graphical abstract Image Highlights • A green electronic with an Al/gelatin composite/Al/paper structure has been demonstrated. • The devices showed forming-free, an ON/OFF ratio of over 105, and uniform current distribution. The ON/OFF ratio of the device after bending 150 cycles can be maintained at 104. • A supply of Fe3+/Fe2+ ions from the gelatin composite can contribute to the resistance switching properties. [ABSTRACT FROM AUTHOR]

We report the fabrication of a paper-sensor for quantitative detection of α -amylase activity in human blood serum. Pieces of filter papers were coated with starch–iodine solution leading to an intense blue coloration on the surface. Dispensing α- amylase solution on the starch–iodine coated paper reduced the intensity of the color because of starch-hydrolysis catalyzed by amylase. The variation in the intensity of the color with the concentration of amylase was estimated in three stages: (i) initially, the paper-surface was illuminated with a light emitting diode, (ii) then, the transmitted (reflected) rays emitted through (from) the paper were collected on a photoresistor, and (iii) the variations in the electrical resistance of the photoresistor were correlated with the amylase concentration in analyte. The resistance of photoresistor decreased monotonically with an increase in amylase concentration because the intensity of the reflected (transmitted) rays collected from (through) the paper increased with reduction in the color intensity on the paper surface. Since a specific bio-reaction was employed to detect the activity of amylase, the sensor was found to be equally efficient in detecting unknown quantities of amylase in human blood serum. The reported sensor has shown the potential to graduate into a point-of-care detection tool for α- amylase. [ABSTRACT FROM AUTHOR]

Aim: Paper is used for various purposes in hospitals. Generally, there are two different types of paper, which are commonly used in our facility: wood-free paper, and paper containing wood. We compared the recoverable proportion of methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43300) from the surface of such papers. Method: The papers were divided into two groups: Group 1: wood-free paper; Group 2: paper containing wood. The papers were contaminated in a standardized procedure with 0.1 mL of a 5×107 CFU MRSA/mL stock solution. Results: The recoverable proportion of MRSA was higher in the woodcontaining papers than in the papers without wood (P=0.043). Conclusion: This study indicates that if paper is purchased for healthcare facilities it should not contain wood, but rather wood-free paper types should be considered. [ABSTRACT FROM AUTHOR]

Potassium methyl siliconate (PMS) was investigated as a simple physicochemical modification in aged paper using silane coupling technique. The PMS-based solution was shown to favor penetration in the cellulose fibers on the paper with suitable uptakes being achieved at low concentrations. The studies of the physicochemical properties of the treated paper (mechanical strength and alkalinity) demonstrated that, besides the required deacidification feature and high level of alkali reserves, the immersion treatment by PMS allowed the enhancement of the mechanical intensities of paper arising from the interaction between Si-OH generated in hydrolysis of PMS and C-OH of cellulose on the paper. Adding ethanol into PMS solution could significantly improve mechanical properties of the aged paper treated by the formula apart from modifying the flatness of the paper. Optimized treatment process was achieved by altering the ratio of ethanol to water in PMS-based solutions. Contact angle measurements indicated the occurrence of hydrophobic character of the papers in immersion treatment with PMS-based solutions. The easy availability of the materials and simplicity of the method rendered it convenient for treatment for aged paper documents. [ABSTRACT FROM AUTHOR]

Printing electronics has led to application areas which were formerly impossible with conventional electronic processes. Solutions are used as inks on top of large areas at room temperatures, allowing the production of fully flexible circuitry. Commonly, research in these inks have focused on organic and metal-oxide ink materials due to their printability, while these materials lack in the electronic performance when compared to silicon electronics. Silicon electronics, on the other hand, has only recently found their way in solution processes. Printing of cyclopentasilane as the silicon ink has been conducted and devices with far superior electric performance have been made when compared to other ink materials. A thermal annealing step of this material, however, was necessary, which prevented its usage on inexpensive substrates with a limited thermal budget. In this work, we introduce a method that allows polycrystalline silicon (poly-Si) production directly from the same liquid silicon ink using excimer laser irradiation. In this way, poly-Si could be formed directly on top of paper even with a single laser pulse. Using this method, poly-Si transistors were created at a maximum temperature of only 150 °C. This method allows silicon device formation on inexpensive, temperature sensitive substrates such as polyethylene terephthalate, polyethylene naphthalate or paper, which leads to applications that require low-cost but high-speed electronics. [ABSTRACT FROM AUTHOR]

Iron gall ink was the most widely used writing ink for paper from the Middle Ages to the twentieth century. Unfortunately, the ink ingredients contain corrosive transition metal ions and acids that cause severe damage to the paper carrier. New or improved paper conservation methods for iron gall ink stabilization are constantly sought. The aim of the study was evaluation of a recently proposed stabilization treatment, adapted to lower relative humidity, applied to various model and historical paper samples containing iron gall ink. The effect of stabilization treatment on paper samples during artificial thermal aging was followed by the determination of the molecular weight distribution by size exclusion chromatography and colorimetry. Migration of iron and copper compounds from the ink lines was monitored by laser ablation inductively coupled plasma mass spectrometry. The results demonstrate that effective stabilization of iron gall ink-containing paper can be successfully achieved by interleaving with papers impregnated with the antioxidant tetrabutylammonium bromide and alkaline buffer under experimental conditions. Negative side effects of the stabilization treatment, such as migration of iron or copper ions from the ink lines and changes of color after the treatment and after accelerated thermal degradation, were limited, proving that the proposed stabilization treatment can be considered for future use by conservators. [ABSTRACT FROM AUTHOR]

Abstract: Selecting an appropriate paper deacidification agent is very important for the deacidification of paper. The use of three deacidification agents (i.e., iso-butylamine, calcium propionate, and borax) is studied for the deacidification of paper using the immersion treatment by investigating the paper surface pH, alkaline residue, paper whiteness, strength, and other performance indicators. Results show the deacidification by borax solution not only results in the promotion of a proper pH range, high level of alkali reserves, and ignorable influence to paper appearance, but also to the enhancement of the mechanical intensities of paper even after artificial aging. Supercritical carbon dioxide (CO2SCF), as a solvent system, is used in the deacidification of acidic papers using the borax solution of water and alcohol. CO2SCF improved the deacidification process by significantly improving the pH value and the base residual value. The borax in supercritical fluids can be better combined with cellulose hydroxyl to improve the mechanical properties of paper substantially. The treatment of borax in CO2SCF could be an alternative for acidic papers. Aside from improving the pH and depositing a sufficient alkaline residual, CO2SCF also strengthens the mechanical properties of treated papers. [Copyright &y& Elsevier]

Abstract: Hierarchical, biomorphic CeO2 hollow fibers with mesoporous tube walls have been fabricated using lens cleaning paper as biotemplates. After sintered at 550°C in air, the cellulosic fibers of paper were converted into micro-tubes composing of CeO2 crystallites with grain size about 8nm. The photocatalytic activity of the CeO2 fibers was evaluated by photodegradation efficiency of methylene blue in aqueous solution under daylight irradiation. The characterized results show that the CeO2 fibers faithfully replicated micro-fibrous structure derived from original template and possessed dramatic enhanced photocatalytic activity compared with bulk CeO2. This simple biotemplate method provides a cost-effective and eco-friendly route to obtain high performance photocatalysts. [Copyright &y& Elsevier]

This article describes a facile method for the preparation of cellulosic catalyst paper: the in situ synthesis of gold nanoparticles (AuNPs) on zinc oxide (ZnO) whiskers, the preferential support for AuNPs, preloaded into a paper matrix. The ZnO paper composites were fabricated using a high-speed and low-cost paper-making technique, and immersed in an aqueous solution of HAuCl4. After drying, fine 5 nm AuNPs were successfully formed on the ZnO whiskers inside the paper matrix. As- prepared AuNPs@ZnO whisker-containing paper (AuNPs@ZnO paper) is similar to ordinary paper products, being flexible, lightweight, and easy to handle. The AuNPs@ZnO paper exhibited a high catalytic efficiency towards the reduction of 4-nitrophenol to 4-aminophenol in aqueous media. Furthermore, the addition of a polyamideamine epichlorohydrin resin provided a wet strength to the AuNPs@ZnO paper, which enables several catalyst recycles with no significant losses in catalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: Pulp and inorganic materials were recovered from paper sludge (PS) using 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and centrifugation. Two types of PS with particle sizes 12μm and 1mm were used. Each type was mixed with [BMIM]Cl (PS:[BMIM]Cl=1:20, w/w) in a polytetrafluoroethylene beaker at 100°C. The inorganic materials were obtained by centrifugal separation of the [BMIM]Cl solution of pulp components and the solid phase, and the pulp dissolved in [BMIM]Cl was regenerated by addition of ethanol. The amount of pulp components recovered from PS with the smaller particle size was almost 100%, and was greater than from PS with the larger particle size. The recovery rate of inorganic materials from PS with small particle size was lower than that from PS with large particle size. [BMIM]Cl recovered by vacuum distillation and dehydration could be re-used for dissolution of pulp components of PS. [Copyright &y& Elsevier]

Analytical filter papers are generally made of fibrous cellulose which has the potential to adsorb metal ions. In this study, blue band ashless filter paper was used to demonstrate one of the sources of error in the determination of the concentration of Fe2+, Co2+, Mn2+, Cd2+, Cu2+, Pb2+ and Zn2+ ions. For this purpose, the metal ion content of standard solutions in the 1-100 mg/l concentration range was analysed via FAAS before and after the filtration process. The corresponding results and the calculated percentage errors due to adsorption are presented. The effect of pH on the adsorption process was also investigated. Activated carbon and soil samples were spiked with each metal ion and the solid phases from the resulting solutions were separated by both filter paper methods and centrifugation. In the statistical estimation of the results, the paired t-test was applied for non-filtered and filtered solutions in the concentration range 1-100 mg/l using the data analysis tools available in MS Excel®. The use of filter paper caused systematic errors, particularly at lower metal concentrations, and hence centrifugation or a filtering process using techniques other than filter paper is favoured as a better approach towards estimating the concentration of heavy metal ions from aqueous solution. [ABSTRACT FROM AUTHOR]

Abstract: A highly sensitive sensing paper that uses the reaction of ozone with azo dye orange I has been developed for ambient ozone monitoring. This reaction results in reaction products, without absorption in visible region, on paper that can be determined by measuring the reflectance spectrum of the paper. The combination of a cellulose sheet, a humectant (glycerol), an alkali (sodium hydroxide) and orange I is needed to achieve a sensitive sensing paper. We found that the pH of the immersion solution used for preparing the sensing paper had a strong influence on the paper''s responsivity to ozone. Ozone detection papers that were made using acidic or neutral immersed solutions were not faded by ozone exposure, whereas those made using a strong alkaline immersion solution were faded by ozone exposure and the color of the paper faded completely at an ozone exposure of about 400ppb×h. We considered an orange I reaction site for ozone using UV–vis spectrum measurements and molecular orbital calculation by comparing experimental results for both orange I and its isomer orange II. It was estimated that the hydrazone form of orange I in alkaline condition would be sensitive to ozone. [Copyright &y& Elsevier]

Abstract: Superhydrophobic alkyl ketene dimer (AKD) layers were successfully produced on top of untreated paper surfaces by a rapid expansion of supercritical CO2 solution (RESS) process. The new method resulted in a degree of hydrophobicity, as measured by contact angles of water droplets on AKD surfaces, dramatically higher, up to 173°, compared to a conventional method consisting in melting AKD granules directly on the paper substrate, giving contact angles of around 109°. Experiments were conducted to investigate the effects of varying pre-expansion pressure (100–300bar), pre-expansion temperature (40 and 60°C) and spraying distance (10 and 50mm) on the properties of the treated surfaces. The surfaces were analyzed regarding AKD particle size, surface morphology and hydrophobicity with the aid of scanning electron microscopy (SEM) and contact angle measurements. The average AKD particle size after RESS processing was between 1 and 2μm depending upon the experimental conditions used, being slightly smaller when using higher pre-expansion pressure and temperature as well as shorter spraying distance. [Copyright &y& Elsevier]

Abstract: The surface chemical and physical character of offset paper was studied before and after application of model fountain solutions based on isopropyl alcohol and an alcohol-free surfactant solution. The paper surface features were characterised with atomic force microscopy and the surface energies were determined by contact angle measurements. Changes in the surface chemical properties induced by the fountain solutions were investigated with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Coated papers wetted with the surfactant solution revealed a slight increase in the root mean square roughness, but the isopropyl alcohol solution led to no observable changes. The change in sub-micro roughness is ascribed not only to substrate swelling or migration of coating constituents but also to the presence of surfactant on the surface. A change in the surface energy and particularly the polar contribution was observed after application of the surfactant solution. The X-ray photoelectron spectroscopy showed an increase in the oxygen-to-carbon ratio, which confirms the presence of surfactant on the surface. Time-of-flight secondary ion mass spectroscopy showed that the isopropyl alcohol solution did not change the elemental composition of the surface whereas the surfactant solution clearly did so. The distribution of surfactant on the surface was confirmed by mapping the characteristic fragments of the molecule. [Copyright &y& Elsevier]

Abstract: Rice straw was used as an alternative raw material to obtain paper pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, α-cellulose and lignin contents of rice straw (viz. 60.7, 41.2 and 21.9%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under next operating conditions: 80% solvent, 180°C and 150min. The solid/liquid ratio was 6. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Diethanolamine pulp exhibited the best viscosity, Kappa index, drainage index and burst index (viz. 956mL/g, 17.0, 21°SR and 1.23kN/g, respectively). Paper made from ethanolamine pulp exhibited the best stretch (1.99%), tear index (0.44mNm2/g) and brightness (41.7%). [Copyright &y& Elsevier]

The article presents a study on the viability of using aqueous solutions of sodium percarbonate as a new method for bleaching discolored paper. Appositely prepared oxidized papers and authentic discolored papers were analyzed to examine the advantages and drawbacks of sodium percarbonate treatments. Results suggest that sodium percarbonate solutions can be a valid substitute to hydrogen peroxide solutions in brightening discolored mechanical pulp papers because it is more stable when stored, safe to use and has low environmental impact.

Abstract: Oil palm empty fruit bunches were used as an alternative raw material to obtain cellulosic pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, α-cellulose and lignin contents of oil palm empty fruit bunches (viz. 66.97%, 47.91% and 24.45%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under two different sets of operating conditions, namely: (a) a 70% solvent concentration, 170°C and 90min; and (b) 80% solvent, 180°C and 150min. The solid/liquid ratio was six in both cases. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Ethanolamine pulp exhibited the best viscosity and drainage index (viz. 636mL/g and 17 °SR, respectively), and paper made from it the best breaking length (1709m), stretch (1.95%), burst index (0.98kN/g) and tear index (0.33mNm2/g). Operating costs can be reduced by using milder conditions, which provide similar results. In any case, the amines are to be preferred to the glycols as solvents for this purpose. [Copyright &y& Elsevier]

Focuses on an experiment to study the influence of accelerated ageing temperature on properties of papers treated with calcium hydroxide or calcium hydroxide combined with methyl cellulose solutions. Two kind of papers used in the experiment; Conditions under which accelerated ageing procedure was carried out; Measurement of chemical, optical and mechanical properties of treated and untreated papers.

We report the fabrication of a plasma-generating device on a paper substrate. This device was fabricated using a screen print process. Plasmas were ignited between two parallel electrodes with a plasma gap of 237 to 710 \mu\m using a dc power source. We demonstrated that a stable helium plasma can be sustained when the substrate is flat, rolled, and folded along various orientations. When the plasma was ignited with a 0.2-\mu\L salt solution droplet with 1.4, 4.6, and 7.8 ng of Li, Na, and K respectively applied to the discharge gap, clear metallic emission lines emanated from the plasma. Our result demonstrates that this paper-based plasma device can be used in analytical applications.\hfill[2012-0006] [ABSTRACT FROM AUTHOR]

The article presents information on some changes that one can bring in an experiment showing the necessity of sunlight in photosynthesis. These changes reduce the number of embarrassments common with this experiment. In the first step of the experiment each side of a growing healthy leaf are pinned with a thin strips of cork underlaid with black paper. The light-weight flexible paper reduces exposure of the leaf to sunlight by conforms closely to the contour of the leaf's surface and as the paper is black, any stray beams entering will be absorbed. If three pins are thrust through the entire combination at a different angle to each other the cork sheets will be held together more firmly. In second step the previously covered leaf or leaves are boiled in two separate applications of alcohol. In the third step the leaves are boiled in water. In the fourth step the leaves are saturated with alcohol. In the fifth step the leaves are soaked in a strong solution of iodine in alcohol. Finally the leaves are washed twice in alcohol.