Area For Absorption Research Articles

Drying and Pyrolysis of Cellulose Nanofibers from Wood, Bacteria, and Algae for Char Application in Oil Absorption and Dye Adsorption

Native cellulose nanofibers (CNF) constitute an abundant resource for pyrolysis leading to char materials offering a wide range of properties and application possibilities. With the aim to produce chars having large surface area and pore volume for dyes adsorption and oil absorption, respectively, we herein explore the slow pyrolysis process of cellulose nanofibers from wood, Cladophora algae and bacteria that were subjected to various drying routes. Whereas algae CNF with their large crystallites lead to high surface area (SBET) substrates using conventional drying from aqueous suspension, CNF from wood having smaller crystallites requires drying from solvents to reach high SBET substrates, which results in chars with a good adsorption capacity for both anionic and cationic dyes. Moreover, the porosity of the CNF substrate can be tuned via an ice-templating freeze-drying procedure reaching values as high as 99.7% and corresponding chars capable of absorbing 64–120 g g–1 of various oils and organic solvents. Besides the absorption/adsorption properties of the chars, we report effects of CNF source and structure on the thermal properties assessed by thermogravimetric and thermomechanical analyses, differential scanning calorimetry, and mass spectrometry, and we identified over 20 decomposition products and 3 expansion events occurring during CNF pyrolysis.

Foreign In3+ treatment improving the photoelectrochemical performance of a hematite nanosheet array for water splitting.

In this work, we found that foreign metallic ion (In3+) treatment enhanced the photoelectrochemical (PEC) activity of hematite nanosheets aligning on a substrate without joining the host lattice. Scanning electron microscopy (SEM) observation indicated that the In3+ ion treatment nearly did not change the size and thickness of the hematite nanosheets during solvothermal synthesis. However, the treatment reduced nanosheet stacking and increased the active surface area of the hematite photoanode. Careful combined analyses involving Energy Dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (XRD) confirmed that In3+ ions were not doped in the hematite nanosheets. Interestingly, after the In3+ treatment, the photoelectrochemical properties of the hematite nanosheets were highly enhanced when they were used as a photoanode for water splitting. The photocurrent density at 1.23 V (versus reversible hydrogen electrode) was 2.6 times as high as that of the hematite without In3+-treatment. The improved PEC activity was deduced to be associated with the increased active surface area for higher light absorption and more photoelectrode/electrolyte junctions, as well as higher carrier density after the In3+-treatment. Furthermore, the efficiencies of the surface charge separation and charge transfer for the In3+-treated hematite nanosheets also increased much more.

Impact of Care in a Multidisciplinary Clinic on a Child With Ultrashort Gut

Abstract Short bowel syndrome (SBS) is a condition characterized by dependence on total parenteral nutrition due to the inability of the intestines to absorb adequate nutrients, electrolytes, and water. SBS is most commonly seen in pediatric patients after extensive small bowel resection due to necrotizing enteroclolitis, intestinal atresias, gastroschisis, or volvulus (Cummings & Mercurio, 2012). The management of children with SBS focuses on maximizing enteral nutrition while mitigating the potential life-threatening complications of central venous line infections and liver failure. The process of slowly advancing enteral feedings and promoting enterocyte proliferation and villus height is termed adaptation (Warner, 2013). These changes provide an increased surface area for nutrient absorption. The promotion of adaptation is the cornerstone of pediatric intestinal rehabilitation. In the following paragraphs, a case study is presented describing the experiences of a child with ultrashort gut and her journey to independence from total parenteral nutrition at 3 years old. Key interventions that may have played a role in this child's success will be discussed.

Performance of Vetiver Grass (Vetiveria zizanioides) for Phytoremediation of Contaminated Water

In tolerance towards metal uptake, there is a need to evaluate the performance of vetiver grass for metal removal to reduce water impurity. This study was aimed to evaluate contaminant removal by vetiver grass at varying root length and plant density and determine the metal uptake in vetiver plant biomass. Pollutant uptake of vetiver grass was conducted in laboratory experiment and heavy metal analysis was done using acid digestion and Atomic Absorption Spectrometry. Findings indicated that the removal of heavy metal was decreased in seven days of the experiment where iron shows the highest percentage (96%; 0.42 ppm) of removal due to iron is highly required for growth of vetiver grass. Removal rate of heavy metals in water by vetiver grass is ranked in the order of Fe>Zn>Pb>Mn>Cu. Results also demonstrated greater removal of heavy metals (Cu, Fe, Mn, Pb, Zn) at greater root length and higher density of vetiver grass because it increased the surface area for metal absorption by plant root into vetiver plant from contaminated water. However, findings indicated that accumulation of heavy metals in plant biomass was higher in vetiver shoot than in root due to metal translocation from root to the shoot. Therefore, the findings have shown effective performance of vetiver grass for metal removal in the phytoremediation of contaminated water.

Abstracts from the In Vitro Toxicology Society Annual Meeting Radisson Blu Hotel Glasgow, United Kingdom November 14–15, 2016

Abstracts from the In Vitro Toxicology Society Annual Meeting Radisson Blu Hotel Glasgow, United Kingdom November 14–15, 2016

Hydrothermal preparation of hierarchical MoS2-reduced graphene oxide nanocomposites towards remarkable enhanced visible-light photocatalytic activity

Hierarchical MoS2-reduced graphene oxide (RGO) nanocomposites were successfully synthesized via a hydrothermal synthesis approach, and their morphology, crystal structure of the composites as well as the photocatalytic activities in the degradation of methylene blue (MB) were investigated using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and UV–vis absorption spectroscopy. The results demonstrated that the MoS2-RGO nanocomposites exhibited excellent photocatalytic performance with a maximum degradation rate up to 80% under visible light irradiation for 30min. To understand the origin of the excellent photocatalytic properties, first-principles calculations were also carried out. It manifested that the excellent photocatalytic activity should be resulted from the existence of the potential electron transfer between conduction band maximum (CBM) of MoS2 and CBM of RGO. Meanwhile, the enhanced visible light absorption, reduced electron–hole pair recombination, and enhanced surface area for absorption of dyes also could be the factors for the excellent photocatalytic performance.

Complete inactivation of photosynthetic activity during desiccation and rapid recovery by rehydration in the aerial microalga Trentepohlia jolithus.

Aerial microalgae are more exposed to harsh and rapidly changing environmental conditions, including desiccation and radiation. Under high light, aerial algae in the desiccated state would be highly subject to photodamage. Therefore, aerial algae need effective protective mechanisms to dissipate excess excitation energy. In this study, the changes in photosynthetic behaviors during desiccation and after rehydration in Trentepohlia jolithus were confirmed using chlorophyll a fluorescence (OJIP) transient, allowing determination of the photoprotection mechanisms of this aerial alga. The filaments of T.jolithus cells at 25% relative air humidity (RH) are significantly shrunken compared with those at 100% and 87% RH, decreasing the surface area for light absorption. At 25% RH, the shape and intensity of the OJIP transient disappeared, but recovered rapidly to the level at 100% RH after 5s of rehydration. Compared with 100% RH, the maximum quantum yield of PSII (φPo ), phenomenological energy fluxes for absorption (ABS/CSm) and active PSII reaction centers (RCs) at 25% RH decreased significantly, the specific energy fluxes for absorption (ABS/RC) increased significantly, but the specific energy fluxes for trapping (TRo/RC) at 25% RH did not change. These parameters at 25% RH recovered rapidly to the level at 100% RH after 5s of rehydration. These results suggest that the efficiency of PSII light absorption and activities of PSII RCs were reversibly down-regulated in desiccated T.jolithus, which may be a special adaptive mechanism for the survivability of aerial microalgae in habitats with rapidly changing water availability.

Changes to the gastrointestinal tract

This article explores changes in the ageing gastrointestinal tract, including: » Diminished sense of taste and smell. » Shrinking of the maxillary and mandibular bones in the jaw. » Slowing of oesophageal peristalsis giving a feeling that something is 'stuck in the throat'. » Relaxation of the lower sphincter leading to gastro-oesophageal reflux. » Reduction in gastric bicarbonate and prostaglandin in mucus increasing susceptibility to stomach ulcers. » Changes in villi in the small intestine reducing the area for absorption. » Overpopulation of bacteria in the small intestine leading to decreased absorption of folic acid and minerals.

A ZnO/TiO2 composite nanorods photoanode with improved performance for dye‐sensitized solar cells

A dye‐sensitized solar cell (DSSC) based on ZnO/TiO2 composite nanorods (NRs) photoanode is fabricated. The power conversion efficiency (PCE) of the ZnO/TiO2 composite NRs film DSSC is 4.36%, which is obviously higher than that of DSSCs based on pure TiO2 NRs (0.6%) and ZnO NRs (3.10%). The enhanced performance of ZnO/TiO2 composite NRs film DSSC can be attributed to the combined effects of ZnO and TiO2 NRs. In this architecture, the thick ZnO NRs overlayer offers a large surface area for enough dye absorption, while the thin TiO2 NRs underlayer not only offers a direct and quick pathway for photoinjected electron transfer along the photoanode but also acts as a blocking layer, which effectively hinders the direct contact between the substrate and the electrolyte resulting in lower carrier recombination.

Ultra-rapid synthesis of highly porous and robust hierarchical ZnO films for dye sensitized solar cells

Dye sensitized solar cells are a promising third generation solar cell technology bearing considerable commercial potential. Here, we present the synthesis of robust, aerogel-like ZnO nanoparticle films with extremely high porosity. These film morphologies enable synthesis of stable cells with linearly increasing photocurrent up to a working-electrode thickness of 200μm. Optimized films led to more than 100% efficiency enhancement with respect to more dense film morphologies made by wet-deposition of the same ZnO nanoparticles. These results suggest that optimization of the semiconductor-electrolyte nano-interface by a hierarchical multi-scale morphology has the potential to minimize electron-holes recombination enabling efficient thick cells with substantially higher surface area for dye absorption.

Sintesa Titanium dioxide (TiO2) untuk Dye-Sensitized Solar Cell dengan Antosianin Bunga Rosella (Hibiscus sabdariffa)

<span>Synthesis of <span><em>titanium dioxide </em><span>(TiO<span>2<span>) for dye sensitized solar cell (DSSC) with anthocyanins <span>rosella (<span><em>Hibisccus Sabdariffa</em><span>) has succesfully been done using sol-gel technique. The <span>semiconductor layer is a very important part of the DSSC since it gives a high surface area for <span>dye absorption which gives rise to high currents. DSSC was formed structually two electrodes <span>sandwiching the electrolyte. The working electrode is TiO<span>2 <span>layer coating on a Fluorine doped <span>Tin Oxide (FTO) glass substrat and sensitified with anthocyanin dye. A counter electrode is <span>carbon coating on the FTO. The fabricated solar cells have an area of 1.5 cm<span>2<span>, soaked in the <span>anthocyanin dye for 24 hours and 48 hours. The sample was characteriz with X-ray diffraction <span>method. The X-ray diffractogram indicates that the sample possesses rutile and anatase phase. <span>The dye absorption measured using spektrofotometer UV-Visible Lambda 25 showed the<br /><span>absorption occurs in the range 440-620 nm. The efficiencies of the solar cells measured by I-V <span>meter Keithley for 24 and 48 hours soaking are 0.0064(6)%, and 0.0151(4)%, respectively.</span></span></span></span></span></span></span></span></span></span></span><br /></span></span></span></span></span></span></span></span></span></span></span>

Hydrothermal growth of ZnO nanowires scaffolds within mesoporous TiO2 photoanodes for dye-sensitized solar cells with enhanced efficiency

ZnO nanowires (ZnO NWs) scaffolds embedded in mesoporous TiO2 photoanodes for dye-sensitized solar cells (DSSCs) are fabricated via an in situ hydrothermal method. The amount of ZnO NWs in the ZnO NWs/TiO2 films can be simply controlled by the initially mixed ZnO seeds in the ZnO/TiO2 nanoparticles (NPs) paste. The ZnO NWs/TiO2 hybrid structure combines advantages of fast electron transport and strong light scattering of ZnO NWs as well as large surface area for dye absorption of TiO2 NPs. The DSSC based on 13μm-thick ZnO NWs/TiO2 film with an optimal ZnO content (6wt% of ZnO seeds) shows power conversion efficiency of 6.41%, enhanced by 18.9% compared to that of pristine TiO2 NPs DSSC. The conversion efficiency can be further improved by increasing the film thickness due to the excellent electron transport property of ZnO NWs as well as the improved dye loading. At a film thickness of 27μm, the ZnO NWs/TiO2 DSSC yields a conversion efficiency of 7.13%, enhanced by 34.3% compared with pristine TiO2 NPs based DSSC.

Ultrastructure of the fetal membranes of the oviparous kingsnake, Lampropeltis getula (Colubridae) as revealed by scanning electron microscopy

ABSTRACTIn reptilian sauropsids, fetal (extraembryonic) membranes that line the eggshell sustain developing embryos by providing for gas exchange and uptake of water and eggshell calcium. However, a scarcity of morphological studies hinders an understanding of functional specializations and their evolution. In kingsnakes (Lampropeltis getula), scanning electron microscopy reveals two major fetal membranes: the chorioallantois and yolk sac omphalopleure. In early development, the chorioallantois contains tall chorionic epithelial cells, avascular connective tissue, and enlarged allantoic epithelial cells. During its maturation, the chorionic and allantoic epithelia thin dramatically and become underlain by a rich network of allantoic capillaries, yielding a membrane ideally suited for respiratory gas exchange. Yolk sac development initially is like that of typical lizards and snakes, forming an avascular omphalopleure, isolated yolk mass (IYM), and yolk cleft. However, unlike the situation in most squamates studied, the omphalopleure becomes transformed into a “secondary chorioallantois” via three asynchronous events: flattening of the epithelium, regression of the IYM, and vascularization by the allantois. Progressive expansion of chorioallantois parallels growing embryonic needs for gas exchange. In early through mid‐development, external surfaces of both the chorionic and omphalopleure epithelium show an abundance of irregular surface protrusions that possibly increase surface area for water absorption. We postulate that the hypertrophied allantoic epithelial cells produce allantoic fluid, a viscous substance that facilitates water uptake and storage. Our findings are consistent with a previous study on the corn snake Pantherophis guttatus, but include new observations and novel functional hypotheses relevant to a reconstruction of basal squamate patterns. J. Morphol. 276:1467–1481, 2015. © 2015 Wiley Periodicals, Inc.

Intestinal morphology, digestive organ size and digesta pH of broiler chickens fed diets supplemented with or without <i>Moringa oleifera</i> leaf meal

The intestinal morphology and pH of digesta of broiler chickens at 35 days old were studied. Birds were reared on these dietary treatments (T). T1, positive control, contained 668 g salinomycin and 500 g zinc bacitracin per kg of feed. Treatments, T2, T3 and T4, contained graded levels of Moringa oleifera leaf meal (MOLM) per kg of feed, namely starter (1, 3, 5 g), grower (3, 9, 15 g) and finisher (5, 15, 25 g). T5 was a negative control (without supplementation). Birds were provided feed and water ad libitum. Birds in T3 had the highest proventriculus digesta pH, and T5 birds the lowest. Birds that were supplemented with MOLM – and surprisingly those from the negative control – had significantly higher caecal digesta pH, while T1 had the highest ileal digesta pH. Duodenal villous length was longest in T2, and shortest in T4. Jejunal villous length was longest in T3 and shortest in T2 birds. T3 and T4 jejunal villi were widest, with T1 birds having the shortest. Ileal villous was longest in T2 and T5 birds, while T3 birds had the shortest. Duodenal surface area for absorption was larger in T2 and T5, and smaller in T4, while T3 had the largest ileal surface area, and T1 the smallest. The jejunal surface area was largest in T3 (53.2) and T4 (50.7), and smallest in T1 (25.0). The current results reveal a regulatory effect of MOLM on the gastrointestinal tract, which could be attributed to the coarseness of the diets, thus raising the pH and resulting in thicker digesta viscosity, which is a clear sign of a healthy gut.

Photovoltaic performance of dye-sensitized solar cells using TiO2 nanotubes aggregates produced by hydrothermal synthesis

This paper reports the synthesis, detailed structural characterization of aggregated [Formula: see text] nanotubes and the application of such aggregated [Formula: see text] nanotubes as photoelectrodes in solar cells (dye sensitized DSCs). A maximum overall conversion efficiency of 7.9% has been achieved, which use conventional dyes without any additional chemical treatments under circumstances of an open-circuit voltage of 710 mV, a short-circuit current density of [Formula: see text], and a fill factor of 66%. This impressive performance is believed to attribute to the micron-sized aggregate structure which may be favorable for light harvesting, the desired high specific surface area and pure anatase phase for dye absorption. This significant improvement in the conversion efficiency indicates that DSCs based on aggregated [Formula: see text] nanotubes are a promising alternative to semiconductor-based solar cells.

Synthesis of Cyclodextrin-functionalized Cellulose Nanofibril Aerogel as a Highly Effective Adsorbent for Phenol Pollutant Removal

Cellulose nanofibril (CNF) aerogels with grafted beta-cyclodextrin (β-CD) were prepared for the adsorption of phenol pollutants from water. Compared with regular wood fibers, CNF aerogel not only can immobilize more β-CDs, but also it provides higher porosity and a larger specific surface area for phenol absorption. The CNF-CD aerogel becomes mechanically robust through chemical crosslinking. It can be easily separated from water after adsorbing phenol pollutants without complicated centrifugation or filtration. A series of studies on phenol adsorption was conducted. The results indicated that the CNF-CD aerogel prepared with a suspension concentration of 3% (w/w) had the highest adsorption capability. In addition, the CNF-CD aerogel showed an excellent reusability. The results indicated that the CNF-CD aerogel is an environmentally friendly and promising adsorbent for removing phenol pollutants from water.

Ultrastructure of the fetal membranes of the oviparous kingsnake, Lampropeltis getula (Colubridae) as revealed by scanning electron microscopy

In reptilian sauropsids, fetal (extraembryonic) membranes that line the eggshell sustain developing embryos by providing for gas exchange and uptake of water and eggshell calcium. However, a scarcity of morphological studies hinders an understanding of functional specializations and their evolution. In kingsnakes (Lampropeltis getula), scanning electron microscopy reveals two major fetal membranes: the chorioallantois and yolk sac omphalopleure. In early development, the chorioallantois contains tall chorionic epithelial cells, avascular connective tissue, and enlarged allantoic epithelial cells. During its maturation, the chorionic and allantoic epithelia thin dramatically and become underlain by a rich network of allantoic capillaries, yielding a membrane ideally suited for respiratory gas exchange. Yolk sac development initially is like that of typical lizards and snakes, forming an avascular omphalopleure, isolated yolk mass (IYM), and yolk cleft. However, unlike the situation in most squamates studied, the omphalopleure becomes transformed into a "secondary chorioallantois" via three asynchronous events: flattening of the epithelium, regression of the IYM, and vascularization by the allantois. Progressive expansion of chorioallantois parallels growing embryonic needs for gas exchange. In early through mid-development, external surfaces of both the chorionic and omphalopleure epithelium show an abundance of irregular surface protrusions that possibly increase surface area for water absorption. We postulate that the hypertrophied allantoic epithelial cells produce allantoic fluid, a viscous substance that facilitates water uptake and storage. Our findings are consistent with a previous study on the corn snake Pantherophis guttatus, but include new observations and novel functional hypotheses relevant to a reconstruction of basal squamate patterns.

Capric Acid Absorption in the Presence of Hydroxypropyl-β-Cyclodextrin in the Rat Ileum using the In Situ Single-Pass Perfusion Technique

The purpose of the present study was to gain quantitative mechanistic insight into the role cyclodextrin carriers may play in the intestinal absorption of highly lipophilic molecules. The physical model approach was employed to investigate capric acid absorption in the rat ileum using the in situ single-pass method with 2-hydroxypropyl-β-cyclodextrin (HPB) present in the perfusate. Two physical models were examined: the flat surface model in which the intestinal wall was treated as a hollow, smooth, circular cylinder, and the villus model in which the intestinal surface allowed for the presence of villi. Capric acid absorption was found to be essentially 100% aqueous boundary layer controlled at low HPB concentrations and increasingly membrane controlled at the higher HPB concentrations. Theoretical calculations based on the experimental data and model parameters were found to be consistent with: at low HPB concentrations, capric acid was mainly absorbed at the villus tips and there was very little capric acid penetration into the intervillus space; in contrast, at 50 mM HPB, there was considerable capric acid penetration into the intervillus space, this corresponding to around a 4.5-fold increase in the accessible area for absorption when compared with 0 mM HPB.

CARBON DIOXIDE REMOVAL IN EMULSION LIQUID MEMBRANE CONTAINING 2-AMINO-2-METHYL-1-PROPANOL /MONOETHANOLAMINE

Absorption using aqueous alkanolamine is commonly used in industry to remove the carbon dioxide. However it has several weaknesses such as corrosion problem and low absorption rate. Emulsion liquid membrane is introduced as an alternatives method for CO2 absorption because it can reduce the corrosion problem and the formation water droplets creates large interfacial area for absorption to occur. 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA) present in the aqueous phase in the form of aqueous droplets, surrounded by the organic solution to form water in oil (w/o) emulsion. In this study, effects of amines ratios and amine quantities, and emulsification time and speed on the ELM stability and CO2 absorption were investigated. The ELM was prepared by homogenizing the aqueous and the organic phases. AMP and MEA were added into sodium hydroxide (NaOH) solution to form aqueous solution, and kerosene and Span-80 were mixed to form the organic solution. The absorption study was carried out in rotating disc contactor (RDC) column. A mixture of 12 v% MEA, 4 v% AMP in 100 ml aqueous solution and 8 v% Span-80 in 100 ml organic phase has high stability and can remove 60% of CO2. The stability of the emulsion remained high even after the absorption. This study proved that ELM has the potential to remove CO2 by using only small amount of amines.

Release of acid phosphatase from extraradical hyphae of arbuscular mycorrhizal fungus Rhizophagus clarus

Arbuscular mycorrhizal (AM) fungi enhance plant uptake of available phosphorus (P) from soil through their extraradical hyphae. The mechanism underlying this P uptake enhanced by AM fungi is the increase in the surface area for absorption of available P. Little is known about utilization of unavailable P by AM fungi. We investigated whether extraradical hyphae of AM fungi release acid phosphatase (ACP). Sterilized Andosol was packed in pots that were separated into the mycorrhizal and hyphal compartments with a nylon net of 30-μm pore size. Seeds of Allium fistulosum L. were inoculated or uninoculated with the AM fungus Rhizophagus clarus (Nicolson & Schenck) Walker & Schüßler. Mullite ceramic tubes were buried in the soil of each compartment, and soil solution was collected. A. fistulosum L. and Linum usitatissimum L. inoculated with R. clarus were grown in sand culture and in vitro monoxenic culture, respectively. Uninoculated A. fistulosum L was grown in hydroponic culture to collect root exudate. The soil solution, hyphal extracts, root extract and root exudates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Shoot P concentration, shoot P content and shoot dry weight were higher in the inoculated treatment than in the uninoculated treatment. Activity staining of the gel revealed that ACP activity at 187 kDa was observed in the soil solution in the inoculation treatment, and in the hyphal extract collected from sand culture and in vitro monoxenic culture, but neither in the root exudate of non-mycorrhizal plant grown in the hydroponic culture nor in the root extracts irrespective of mycorrhizal status. Those results provide strong evidence that the corresponding activity in the soil solutions in soil culture is of R. clarus CK001 origin. These findings suggest that the fungus releases ACP from extraradical hyphae into the hyphosphere.