bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporation of Acrylate Based Spiropyran Monoliths in Micro-Fluidic Devices for Photo-Controlled Electroosmotic Flow
Authors: Scarmagnani Silvia , Walsh Zarah , Benito-Lopez Fernando , Macka Mirek , Paull Brett , Diamond Dermot
Published: October 2010

Spiropyran photochromic compounds can be switched using light exposure between a non-polar spiro form (SP) and a zwitterionic merocyanine form (MC) that is subject to protonation (MC-H+). It has recently been demonstrated by Walsh et al. that, under acidic conditions, electroosmotic flow (EOF) generated in vinyl based spiropyran monoliths can be modulated using light irradiation [1].
In this paper, we report a spiropyran-modified acrylate based monolith which is particularly sensitive to protonation in the MC form, producing a positively charged surface that converts to the unpolar SP form by exposure to white light. When the MC-H+ form is dominant, it produces a charged surface which enables a relatively high flow rate (up to 1.6 μl/min) to be generated under electroosmotic conditions. Upon exposure to white light, the concentration of MC-H+ decreases due to the photo-conversion to the uncharged SP form, with up to 20% reduction of the EOF. The process is reversible, and removal of the light source results in a flow increase back to the original rate. The ability to alter flow rates in micro-fluidic channels using light has very significant implications, as it could dramatically simplify the manner in which micro-flow systems are controlled.
Bone-Mimetic Laminated Nano-Structures for Regeneration of Skeletal Tissues
Authors: Jabbari Esmaiel
Published: October 2010

Bone exhibits hierarchical levels of organization from macroscopic to microscopic to nanoscale. The objective of this work was to develop a bonemimetic composite matrix to provide structural support to the regenerating region and to support the cascade of osteogenic differentiation of progenitor marrow stromal (BMS) cells. Sheets of poly(L-lactide) (L-PLA) nanofibers, fabricated by electrospinning, were coated with a hydrogel/apatite precursor solution, stacked and pressed together, and allowed to crosslink by photopolymerization to form a peptide-reinforced hydrogel/apatite laminated composite. Addition of an osteonectin-derived glutamic acid peptide (Glu6) and lamination resulted in an order of magnitude increase in modulus of the composite to within the range reported for wet human cancellous bone. Lamination significantly increased the extent of mineralization of BMS cells and the laminates reinforced with apatite nanocrystals and conjugated with integrin-binding focal-point adhesion RGD peptide (Lam-RGD-HA) had 3-fold higher calcium content and higher expression of osteogenic markers osteopontin and osteocalcin (compared to laminates without apatite or RGD) after 21 days of incubation in osteogenic media. Laminated osteon-mimetic structures have the potential to provide mechanical strength to the regenerating region as well as supporting the differentiation of progenitor cells to the osteogenic lineage.
Engineered Biomimetic Nanofibers for Regenerative Medicine
Authors: Ramakrishna Seeram , Venugopal Jayarama Reddy , Liao Susan
Published: October 2010

Attempts have been made to fabricate nanofibrous scaffolds to mimic the chemical composition and structural properties of extracellular matrix (ECM) for tissue/organ regeneration. Nanofibers with various patterns have been successfully produced from synthetic and natural polymers through a relatively simple technique of electrospinning. The resulting patterns can mimic some of the diverse tissue-specific orientation and three-dimensional (3D) fibrous structure. Studies on cell-nanofiber interactions have revealed the importance of nanotopography on cell adhesion, proliferation and differentiation. Our recent data showed that hematopoietic stem cells (HSCs) as well as mesenchymal stem cells (MSCs) can rapidly and effectively attached to the functionalized nanofibers. Mineralized 3D nanofibrous scaffold with bone marrow derived MSCs has been applied for bone tissue engineering. The use of injectable nanofibers for cardiac tissue engineering applications is attractive as they allow for the encapsulation of cardiomyocytes/MSCs as well as bioactive molecules for the repair of myocardial infarction. Duplicate 3D heart helix microstructure by the nanofibrous cardiac patch might provide functional support for infarcted myocardium. Furthermore, clinical applications of electrospun nanofibers for regenerative medicine are highly feasible due to the ease and flexibility of fabrication with the cost-effective method of making nanofibers.
A Hydroxyapatite-Collagen Composite Useful to Make Bioresorbable Scaffolds for Bone Reconstruction
Authors: Guerra Giulio D. , Cristallini Caterina , Rosellini Elisabetta , Barbani Niccoletta
Published: October 2010

Composites between hydroxyapatite (HA) and collagen (Col) may be used to make bioresorbable scaffolds for bone reconstruction. A suspension of micro-particles (average diameter ≅ 30 µm) of HA annealed at 1100°C in Col solution (80:20 HA to Col weight ratio) was manufactured in films by casting, and then some films were cross-linked by glutaraldehyde vapours. Cross-linked sponges were obtained by treating the suspension with transglutaminase, and by lyophilizing the so obtained gel. Characterization by scanning electron microscopy, water sorption test, Col release in water, thermogravimetric analysis and differential scanning calorimetry shows that the cross-linking enhances the stability of the composite. Conversely, neither the interactions between HA and Col, detected by spotlight FT-IR, nor the degradation by collagenase, which is a requirement for the bioresorbibility, are affected by the cross-linking.
Study on Bone Cell Adaptability of α-TCP/HAp Functionally Graded Porous Beads for Biomaterials Application
Authors: Ohtake S. , Asaoka T. , Furukawa K. , Ushida T. , Tateishi T.
Published: October 2010

Porous beads of bioactive ceramics such as HAp, TCP are considered to be promising as excellent scaffolds for cultivating bone cells. To realize this type of beads which maintains the function of scaffold with
sufficient strength up to growth of new bone, and is expected to absorbed completely after the growth, a-TCP/ HAp functionally graded porous beads were fabricated. HAp is bioactive material which has both high strength and better tissue-adhesive properties, but that is not readily absorbed by the human body. On the contrary, a-TCP is highly bioabsorbable; it is quickly absorbed by the body, and, therefore, disappears before bone is completely replaced. Fabricated new beads are composed of a-TCP at the center and HAp at the surface, to control the solubility in living body. Bone cell adaptability of these beads were confirmed in vitro.
Self-Buckling at the Nanoscale
Authors: Pugno Nicola Maria
Published: October 2010

In this paper the self-buckling of nanostructures, such as nanotubes, fullerenes and peapods, is analytically treated; this surprising phenomenon is due to the interaction among the nanostructures caused by the surface energy; it is peculiar of the nanoscale and has not a macroscopic counterpart. The influence of the surrounding nanostructures on one of them in a crystal is nearly identical to that of a liquid having surface tension equal to the surface energy of the solid. For the beneficial implications of the self-buckling on the overall mechanical strength see Pugno (2010; The design of self-collapsed super-strong nanotube bundles, Journal of the Mechanics and Physics of Solids, Available Online).
Modeling the Elastic Anisotropy of Woven Hierarchical Tissues: Experimental Comparison on Biological Materials and Design of a New Class of Scaffolds
Authors: Pugno Nicola Maria , Chen Qiang
Published: October 2010

This paper models the elastic properties of 2-D woven hierarchical tissues, assuming an orthotropic material of warp and fill yarns at level 0. Considering matrix transformation and stiffness averaging, stiffness matrices of warp and fill yarns of the tissue at level i are employed to calculate those of the tissue at level i+1. We compare our theory with another approach from the literature on tendons and experiments on leaves performed by ourselves. The result shows the possibility of designing a new class of hierarchical 2-D scaffolds with desired elastic anisotropy, better matching the anisotropy of the biological tissues and thus maximizing the regeneration.
Catastrophic Instabilities in the Fracture of Nanotube Bundles
Authors: Pugno Nicola Maria , Abdalrahman Tamer
Published: October 2010

In a recent letter, Xiao et al. [3] interpreted experimental results on the failure of nanotube bundles using Weibull Statistics. The prediction of the force versus strain curve was a smooth curve, only partially able to capture the observed discrete behavior of the bundle. In particular, abrupt jumps in the force, at nearly constant strains, were clearly observed experimentally, each of them corresponding to the failure of a sub-bundle. Accordingly, we have developed a simple modification of the Weibull Statistics able to treat the observed catastrophic failure of the bundle, considering a linear or nonlinear elastic constitutive law.
XPS Characterization of Iron Oxide and Gold Nanoparticles for Tumor Care
Authors: Speranza Giorgio , Minati L. , Torrengo Simona , Rossi Barbara , Migliaresi Claudio , Maniglio Devid , Dalbosco Luca
Published: October 2010

Superparamagnetic iron oxide nanoparticles (SPIO) have a wide range of applications,
including high-density magnetic storage, catalytic and separation processes, magnetic resonance
imaging (MRI), in vivo imaging of tumor progression. One advantage is that they are sufficiently
inert to be injected to the human body without significant counter effects. For these reasons, SPIO
are utilized as carriers to target tumor tissues with the aim to visualize the extension of the
malignant affection and to cure it. A mimetic coating is needed to overcome the immune system and
ensure a sufficient long life to allow SPIO to reach the tumor tissue. In addition, gold nanoparticles
were functionalized and coated with the same mimetic film. Differently from iron oxide NPs, those
based on gold may be utilized to perform Surface Enhanced Raman Spectroscopy (SERS) to obtain
spatial and chemical information. In this work, we present preliminary results on iron oxide and
gold-based NPs synthesized in our laboratories. A full characterization was performed by means of
XPS to study both the chemical composition of the SPIO nanoparticles, of their mimetic coatings,
and to get structural information.
Development of Pseudoboehmites for Nanosystems to Release Acyclovir
Authors: Júnior Antonio Hortencio Munhoz , Novickis R.W. , Braunstein Faldini Sonia , Ribeiro Roberto Rodrigues , Maeda Claudio Yuji , de Miranda L.F.
Published: October 2010

The production of confined or adsorbed drugs in inorganic matrix has been increasing in areas like material science and pharmaceutical due to the possibility of the production of nanoadsorbed or encapsulated molecules with new properties like chemical stability, enhancing solubility and controlled release, what implies in new applications of materials. In the present work, a nanocomposite of a fine ceramic material, pseudoboehmite, and acyclovir, was prepared. Pseudoboehmite is based on a monohydroxide aluminum oxide produced from a synthetic route using ammonium hydroxide and aluminum nitrate or chloride as precursors in the sol-gel process. These systems had been characterized by the following techniques: MEV, TG/DSC, FTIR and UV-vis. The exposition of the drug to the pseudoboehmite at the dissolution equipment was at 37°C and 100rpm for 30 minutes. With the purpose to observe the interaction of the drug with the adsorbent, it was obtained the concentration of the drug in the solution, before and after the adsorption, using the UV-vis spectroscopy technique. The acyclovir has increased its solubility in an HCl 0,1M solution, when the weight ratio of Pseudoboehmite: Acyclovir 1:1 was used.
Study of Chitosan Addition in the PVP/PVAL Polymeric Blend
Authors: Terence Mauro Cesar , de Miranda L.F. , Braunstein Faldini Sonia , Junqueira de Castro Paula
Published: October 2010

The main objective of this project is the study of the addition of chitosan in the polymeric blend of PVP/PVAL to get a biocompatible hydrogel that can be used as a system of controlled release of drugs. The polymeric blend usage is a recent development that expanded the applications of the polymers, due to the improvement of the properties of a single polymer even if they appear to be conflicting. PVP and PVAL were chosen because they present the main required characteristics to the formation of a hydrogel, such as water absorption and crosslinked formation. The flexibility of the PVP was added with the mechanical resistance of the PVAL. The chitosan, biological active polymer molecules, addition is to increment the interaction between the hydrogel and the organism. With the concentrations of PVP and PVAL defined, solutions with different levels of chitosan were made to check which presented better properties.
Development of Craniofacial Implants Produced by Metal Injection Molding of Titanium Alloy Using Novel Binder System Based on Palm Oil
Authors: Ibrahim Rosdi , Azmirruddin M. , Jabir M. , Ridhuan M. , Muhamad M. , Rafiq M. , Kasim N.A. , Muhamad Salina
Published: October 2010

Metal Injection Molding (MIM) is a cost-effective technique for producing small, complex,
precision parts in high volumes. MIM consists of four main processing steps: mixing, injection
molding, debinding and sintering. In the mixing step, the powder titanium alloy (Ti6Al4V) medical
grade is mixed with a binder system based on palm stearin to form a homogeneous feedstock. The
rheological studies of the feedstock have been determined properly in order to success during injection
into injection molding machine. After molding, the binder holds the particles in place. The binder
systems then have to be removed completely through debinding step. Any contamination of the binder
systems will affect the final properties of the parts. During debinding step, solvent extraction debinding
has been used to remove partly of the binder systems. The debound part is then sintered at high
temperature under control atmosphere furnace. The properties of the sintered craniofacial implants then
was measured and compared. The sintered craniofacial implants also then were determined in term of
in-vitro cytotoxicity study using mouse fibroblast lines L-929. The results show that the sintered
craniofacial implants of titanium alloy produced by MIM fullfill the in-vitro cytotoxicity test.
Creation of Superelastic Functional Properties in a Ti-50.7%Ni Wire for the Stapler Suturing of Blood Vessels
Authors: Khmelevskaya I. , Soutorine M. , Prokoskin S. , Ryklina E.
Published: October 2010

The technique of aorta-coronary shunting offered by Dr. M. Soutorine by means of the original stapler developed by "Endogene" allows suturing blood vessels by superelastic Тi-Ni staples on «working heart» (without heart switching-off). The material for staples is a 0.30 and 0.315 mm diam. wire which was studied by DSC, shape recovery and mechanical tests. Thermomechanical treatment (TMT) comprised warm drawing, low- temperature (LTMT) by cold drawing with 25-30% strain in the last pass and following post-deformation annealing (PDA). LTMT leads to increasing of yield stress in comparison with warm drawing. Treatment of wire under LTMT+PDA allows obtaining the highest characteristics of functional properties of the wire. The difference between “dislocation” and “transformation” yield stresses  Δ=900 MPa. Critical stress of superelastic recovery after TMT on the average is 1.5-2 times higher in comparison with warm drawing. The maximum completely recoverable strain r,1max=6.5%. The maximum obtained force value of staples is РrSE=6.5 Н. The shape recovery rate of staples was 85-97 % that provided its functionality. Storage in the stapler in straightened condition within 1 month does not worse the staples.
An Efficient Low-pH Range Sensitive Artificial Muscle for Future Active Implantable Systems
Authors: Tondu Bertrand , Bardou Nicole , Mathé Stéphane
Published: October 2010

Based on recent experiments made by the present authors on a “pH-muscle” functioning in an admissible physiologically pH-range, a global analysis is developed for a future “artificial muscle implant” both safe and efficient. A scheme of a possible future artificial muscle implant is shown associating our current prototype, whose skeletal muscle-like behaviour is provided by McKibben artificial muscle technology, with the use of a bio-compatible micro-organism, to be specified, which would be able to generate the necessary ionic-strength change to the swelling and de-swelling of the ion-sensitive agent placed inside the McKibben structure. Preliminary experimental results are reported of a 10 cm long artificial muscle and 8 mm external diameter filled with a RCOOH commercial Amberlite resin generating a maximum force of 80 N with buffer solutions of pH between 4.5 and 8.4 in some tens of minutes with the hope of obtaining quicker responses by use of more specific ion-sensitive polymers.
Self-Assembled N-Succinyl-Chitosan Nanofibers for Reduced Protein Adhesion
Authors: Dayyoub Eyas , Bakowsky Udo
Published: October 2010

Protein adhesion on biomaterial surfaces plays a major role in determining their biocompatibility and cell responses. The goal of this study was to produce chitosan-based coatings of implant material polyurethane (PUR) for reduced human serum albumin (HSA) adhesion. Succinic anhydride was employed for modifying chitosan and synthesis of N-succinyl-chitosan (NSCS) which was used as a matrix coating of PUR. NSCS showed self-assembly behaviour as nanofiber structures onto PUR surface. Atomic force microscopy (AFM) has emerged as useful tool for the molecular force measurements and therefore it has been chosen to investigate the adhesion properties of Human serum albumin (HSA) on the new matrix coatings and other three implant materials PUR, Silicon and Titanium.
HSA molecules were covalently bound to the AFM tip by the use of cyanuric chloride as bivalent linker. Analyzing the force curves demonstrated the antiadhesive properties of the NSCS films in comparison with the uncoated PUR, Silicon and Titanium.
Mineralization of Eroded Dental Enamel Seeded with Fluoride and a Tricalcium Phosphate Ternary Biomaterial
Authors: Karlinsey Robert L. , Mackey Allen C. , Walker Emily R. , Walker Trenton J. , Fowler Christabel X.
Published: October 2010

The inability to sufficiently prevent and/or repair chemically-etched dental enamel serves as one example that underlines the importance and need for the development of innovative biomaterials for therapeutic applications. In this work we explored the seeding capability of 225 ppm and 1100 ppm fluoride with and without a novel β-tricalcium phosphate-silica-urea (TCP-Si-Ur) biomaterial (concentrations of 20, 40, 80, and 200 ppm) to mineralize into acid-etched bovine enamel. The nature of the mineralization was evaluated by measuring the fluoride and phosphate uptake into the eroded enamel, as well as the orthophosphate microstructure using infrared (IR) spectroscopy. These enamel fluoride uptake and IR experiments revealed a fluoride dose response exists for eroded enamel treated with 225 and 1100 ppm F. The inclusion of 20, 40, and 80 ppm TCP-Si-Ur with 225 ppm F was similar to 225 ppm F alone and did not produce a fluoride uptake dose response; however, 200 ppm TCP-Si-Ur combined with 1100 ppm F improved raw fluoride uptake relative to 1100 ppm F. Furthermore, we found the combination of either 225 ppm or 1100 ppm fluoride plus TCP-Si-Ur at different loading levels leads to unique and significant mineral integration into the PO4 enamel network, including the formation of P-F bonds. The observations reported herein demonstrate the combination of fluoride plus a novel TCP-Si-Ur biomaterial produces synergistic mineralization and bears significantly on eroded enamel microstructure.
A New Generation of Scaffolds for Bone Tissue Engineering
Authors: Bellucci Devis , Cannillo Valeria , Cattini Andrea , Sola Antonella
Published: October 2010

The design of bioceramic scaffolds, i.e. artificial structures employed as temporary templates for cell proliferation, is a crucial issue in bone tissue reconstruction and regeneration. An ideal scaffold should be highly porous and bioactive. Additionally, a resistant and permeable surface is required in order to have manageable samples. The production of scaffolds by means of the widely used replication method can lead to samples with weak and brittle surfaces and poor mechanical properties, therefore alternative preparation procedures are necessary. In this work a new protocol to realize bioceramic scaffolds is presented. The obtained samples have an original structure, characterized by an external resistant surface together with a highly porous internal network. The external surface, which behaves as a load-bearing structure for the entire scaffold, guarantees high permeability and manageability. Here the proposed protocol is briefly discussed, together with an overview on the structure of the realized samples. Finally, some preliminary data regarding the scaffolds in-vitro bioactivity are reported.
XRD Studies on Transformation of Calcium-Deficient Apatite to β and α TCP in Dynamic and Technological Conditions
Authors: Handke Bartosz , Zima Aneta , Paszkiewicz Zofia , Ślósarczyk Anna
Published: October 2010

Calcium phosphates (CaPs): hydroxyapatite (HA) and TCP are common biomaterials used in orthopedic, dental and maxillofacial surgery as bone fillers and also as drug carriers. Studies of the β→α TCP transformation and formation of mono-, bi- or three-phase CaPs materials: βTCP-αTCP-HA are of principal importance. Stability of calcium phosphate ceramics depends on many factors. Our dynamic studies by high temperature XRD measurements showed that monoclinic αTCP was a considerably stable phase after its creation completed at 1200°C. Different phase composition was obtained in technological conditions.
Novel Biomaterials and Nano-Biotechnology Approaches in Tumor Diagnosis
Authors: Dinda Amit Kumar , Prashant Chandravilas Keshvan
Published: October 2010

Each year 10.9 million people worldwide are diagnosed with cancer and it is the third most common disease in world. Early diagnosis of cancer and cure are major challenges. Recent advances in development of novel biomaterials as well as rapid progress in the area of nano-biotechnology has potentials to change all the current modalities of cancer diagnosis and management. The unique physical and chemical properties of nanomaterials are extremely helpful for detection of biomarkers of the disease, molecular imaging as well as specific targeted therapy sparing the normal organs. Nanoparticle (NP) has large surface area which can be conjugated or coated with different molecular probes for diverse detection system (optical, electrical, magnetic etc.) as well as used as a vehicle to carry different biomolecules and anticancer drugs to tumor cells. Semiconductor quantum dot (QD) with novel optical and electronic properties helped to devise a new class of NP probes for molecular, cellular, and in vivo imaging. A large variety of materials ranging from metal, ceramic, polymer, lipid, protein and nucleic acid are used for developing novel nanoparticles with multiple functions which can detect different aspects of cancer biology and progression. The major issue of concern is biocompatibility and safety of these materials and their fate after in-vivo use. However with collaborative interdisciplinary research it will be possible to develop safer nanomaterials in future
Repair of DNA Alkylation Damage by the Escherichia coli Adaptive Response Protein AlkB as Studied by ESI‐TOF Mass Spectrometry
Authors: Li Deyu , Delaney James C. , Page Charlotte M. , Chen Alvin S. , Wong Cintyu , Drennan Catherine L. , Essigmann John M.
Published: October 2010

DNA alkylation can cause mutations, epigenetic changes, and even cell death. All living organisms have evolved enzymatic and non‐enzymatic strategies for repairing such alkylation damage. AlkB, one of the Escherichia coli adaptive response proteins, uses an α‐ketoglutarate/Fe(II)‐dependent mechanism that, by chemical oxidation, removes a variety of alkyl lesions from DNA, thus affording protection of the genome against alkylation. In an effort to understand the range of acceptable substrates for AlkB, the enzyme was incubated with chemically synthesized oligonucleotides containing alkyl lesions, and the reaction products were analyzed by electrospray ionization time‐of‐flight (ESI‐TOF) mass spectrometry. Consistent with the literature, but studied comparatively here for the first time, it was found that 1‐methyladenine, 1,N 6‐ethenoadenine, 3‐methylcytosine, and 3‐ethylcytosine were completely transformed by AlkB, while 1‐methylguanine and 3‐methylthymine were partially repaired. The repair intermediates (epoxide and possibly glycol) of 3,N 4‐ethenocytosine are reported for the first time. It is also demonstrated that O 6‐methylguanine and 5‐methylcytosine are refractory to AlkB, lending support to the hypothesis that AlkB repairs only alkyl lesions attached to the nitrogen atoms of the nucleobase. ESI‐TOF mass spectrometry is shown to be a sensitive and efficient tool for probing the comparative substrate specificities of DNA repair proteins in vitro.
Impact of transported background ozone inflow on summertime air quality in a California ozone exceedance area
Authors: Parrish D. D. , Aikin K. C. , Oltmans S. J. , Johnson B. J. , Ives M. , Sweeny C.
Published: October 2010

Abstract. Ozone sondes launched from Trinidad Head, California provide a measure of background O3 transported ashore, and allow an evaluation of the impact of this transport on air quality in California's Northern Sacramento Valley. A strong summertime vertical O3 gradient and correlation analysis indicate that O3-rich air from above the marine boundary layer is transported to the surface. Surface O3 is found to increase proportionally to the transported background. At the surface site experiencing the highest O3 concentrations, the mean maximum daily 8-h average (MDA8) O3 on exceedance days (i.e. those days when MDA8 O3 exceeds 75 ppbv) is 20 ppbv higher than on non-exceedance days. The transported background O3, as measured 22 h earlier by the Trinidad Head sondes, accounts for more than half (11 ppbv) of this difference. This finding contrasts with conclusions from model calculations that indicate the US policy relevant O3 background is generally 15–35 ppbv, and that it is lower, rather than higher, during pollution episodes. The present work indicates that O3 transported on hemispheric scales substantially impacts air quality in some areas of the US.
A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases
Authors: Chen J. , Venables D. S.
Published: October 2010

Abstract. Accurate absorption spectra of gases in the near-ultraviolet (300 to 400 nm) are essential in atmospheric observations and laboratory studies. This paper describes a novel incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instrument for measuring very weak absorption spectra from 335 to 375 nm. The instrument performance was validated against the 3B1−X1A1 transition of SO2. The measured absorption varied linearly with SO2 column density and the resulting spectrum agrees well with published spectra. Using the instrument, we report new absorption cross-sections of O3, acetone, 2-butanone, and 2-pentanone in this spectral region, where literature data diverge considerably. In the absorption minimum between the Huggins and Chappuis bands, our absorption spectra fall at the lower range of reported ozone absorption cross-sections. The spectra of the ketones agree with prior spectra at moderate absorptions, but differ significantly at the limits of other instruments' sensitivity. The collision-induced absorption of the O4 dimer at 360.5 nm was also measured and found to have a maximum cross-section of ca. 4.0 × 10−46 cm5 molecule−2. We demonstrate the application of the instrument to quantifying low concentrations of the short-lived radical, BrO, in the presence of stronger absorptions from Br2 and O3.
Nitrous oxide emission from highland winter wheat field after long-term fertilization
Authors: Wei X. R. , Hao M. D. , Xue X. H. , Shi P. , Horton R. , Wang A. , Zang Y. F.
Published: October 2010

Abstract. Nitrous oxide (N2O) is an important greenhouse gas. N2O emissions from soils vary with fertilization and cropping practices. The response of N2O emission to fertilization of agricultural soils plays an important role in global N2O emission. The objective of this study was to assess the seasonal pattern of N2O fluxes and the annual N2O emissions from a rain-fed winter wheat (Triticum aestivum L.) field in the Loess Plateau of China. A static flux chamber method was used to measure soil N2O fluxes from 2006 to 2008. The study included 5 treatments with 3 replications in a randomized complete block design. Prior to initiating N2O measurements the treatments had received the same fertilization for 22 years. The fertilizer treatments were unfertilized control (CK), manure (M), nitrogen (N), nitrogen + phosphorus (NP), and nitrogen + phosphorus + manure (NPM). Soil N2O fluxes in the highland winter wheat field were highly variable temporally and thus were fertilization dependent. The highest fluxes occurred in the warmer and wetter seasons. Relative to CK, m slightly increased N2O flux while N, NP and NPM treatments significantly increased N2O fluxes. The fertilizer induced increase in N2O flux occurred mainly in the first 30 days after fertilization. The increases were smaller in the relatively warm and dry year than in the cold and wet year. Combining phosphorous and/or manure with mineral N fertilizer partly offset the nitrogen fertilizer induced increase in N2O flux. N2O fluxes at the seedling stage were mainly controlled by nitrogen fertilization, while fluxes at other plant growth stages were influenced by plant and environmental conditions. The cumulative N2O emissions were always higher in the fertilized treatments than in the non-fertilized treatment (CK). Mineral and manure nitrogen fertilizer enhanced N2O emissions in wetter years compared to dryer years. Phosphorous fertilizer offset 0.50 and 1.26 kg N2O-N ha−1 increases, while manure + phosphorous offset 0.43 and 1.04 kg N2O-N ha−1 increases by N fertilizer for the two observation years. Our results suggested that the contribution of single N fertilizer on N2O emission was larger than that of NP and NPM and that manure and phosphorous had important roles in offsetting mineral N fertilizer induced N2O emissions. Relative to agricultural production and N2O emission, manure fertilization (M) should be recommended while single N fertilization (N) should be avoided for the highland winter wheat due to the higher biomass and grain yield and lower N2O flux and annual emission in m than in N.
MODIS observed phytoplankton dynamics in the Taiwan Strait: an absorption-based analysis
Authors: Shang S. , Dong Q. , Lee Z. , Li Y. , Xie Y. , Behrenfeld M.
Published: October 2010

Abstract. This study uses MODIS observed phytoplankton absorption coefficient (aph) as a preferable index of pigmentation to characterize phytoplankton variability in optically complex waters. We chose a quasi-analytical bio-optical inversion algorithm (QAA) to derive aph from remote sensing reflectance (Rrs, both in situ and MODIS measured) and then evaluated the Rrs derived aph by comparing them with match-up in situ measured aph collected in both oceanic and very nearshore waters in the Taiwan Strait (TWS). For the data with matching spatial and temporal window, it is found that the average percentage error (ε) between MODIS Rrs derived aph at 443 nm (aph(443), abbreviated as Aph) and field measured Aph is 33.8% (N = 30, Aph ranges from 0.012–0.537 m−1), with a root mean square error in log scale (RMSE) of 0.226. By comparison, ε is 28.0% (N = 88, RMSE = 0.150) between ship-borne Rrs derived Aph and field measured Aph. Values of ε as large as 135.6% (N = 30, RMSE = 0.383) are found between MODIS Rrs derived chlorophyll-a (chl-a, OC3M algorithm) and field measured chl-a. Based on these evaluation results, we applied QAA to MODIS Rrs data between 2003–2009 to derive climatological monthly mean Aph for the TWS. Three distinct features of phytoplankton dynamics are identified. First, Aph is low and the least variable in the Penghu Channel, where the South China Sea water enters the TWS. This region maintains slightly higher values in winter (~17% higher than that in the other seasons) due to surface nutrient entrainment under winter wind-driven vertical mixing. Second, Aph is high and the most variable in the mainland nearshore water, with values peaking in summer (June–August) when river plumes and coastal upwelling enhance surface nutrient loads. Interannual variation of bloom intensity in Hanjiang River estuary in June is highly correlated with alongshore wind stress anomalies, as observed by QuikSCAT. The year of minimum and maximum bloom intensity is in the midst of an El Nino and a La Nina event, respectively. Third, a high Aph patch appears between April and September in the middle of the Southern TWS, corresponding to high thermal frontal probabilities, as observed by MODIS. Our results support the use of satellite observed Aph for time series analyses of phytoplankton dynamics in coastal ocean regions, where satellite chl-a retrievals can suffer from artifacts associated with non-biotic optically active materials.
Production and consumption mechanisms of N2O in the Southern Ocean revealed from its isotopomer ratios
Authors: Boontanon N. , Watanabe S. , Odate T. , Yoshida N.
Published: October 2010

Abstract. The distribution of dissolved N2O in the Southern Ocean at 140° E was measured during the austral summer (February–March 2002) in the framework of the 43rd Japanese Antarctic Research Expedition (JARE-43). Surface-dissolved N2O was undersaturated (about 94% saturation), and the calculated mean sea-air flux rate was −3.68±2.57 μmol m−2 d−1. The vertical distributions tested exhibited N2O maxima at around 150–300 m (ΔN2O, 7.90–8.51 nM) below the chlorophyll-rich layer, which coincided with the layer of minimum oxygen. These observations strongly suggest that N2O production and consumption are related to apparent oxygen utilization (AOU). In the deeper layer, the presence of anoxic microsites within particles, together with the horizontal and vertical movement of cold water around Antarctica, is one of the parameters that govern the intramolecular distribution of the isotopic composition of N2O. The N2O isotopic compositions in the maximum layer were +7.3 to +8.2‰ for δ15Nbulk and +43.5 to +46.2‰ for δ18O associated with the coupling of nitrification and denitrification production mechanisms. Site preference decreased from an average 17‰ at the surface to the ΔN2O maximum and slightly increased with depth up to 24‰ at the deeper region. The influence of deep Southern Ocean N2O on the global N2O budget is estimated to be about 46.2±5.3 Mg N2O-N d−1, which represents the amount that can escape to the atmosphere and thus contribute to emissions into the world's oceans.
Design and implementation of the infrastructure of HadGEM3: the next-generation Met Office climate modelling system
Authors: Hewitt H. T. , Copsey D. , Culverwell I. D. , Harris C. M. , Hill R. S. R. , Keen A. B. , McLaren A. J. , Hunke E. C.
Published: October 2010

Abstract. This paper describes the development of a technically robust climate modelling system, HadGEM3, which couples the Met Office Unified Model atmosphere component, the NEMO ocean model and the Los Alamos sea ice model (CICE) using the OASIS coupler. Details of the coupling and technical solutions are documented in the paper in addition to a description of the configurations of the individual submodels. The paper demonstrates that the implementation of the model has resulted in accurate conservation of heat and freshwater across the model components. The model performance in early versions of this climate model is briefly described to demonstrate that the results are scientifically credible. HadGEM3 is the basis for a number of modelling efforts outside of the Met Office, both within the UK and internationally. This documentation of the HadGEM3 system provides a detailed reference for developers of HadGEM3-based climate configurations.
Modeling the monthly mean soil-water balance with a statistical-dynamical ecohydrology model as coupled to a two-component canopy model
Authors: Kochendorfer J. P. , Ramírez J. A.
Published: October 2010

Abstract. The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using separate potential rates of transpiration and bare-soil evaporation. Those potential rates, along with the rate of evaporation from canopy interception, are calculated using the two-component Shuttleworth-Wallace (1985) canopy model. In addition, the soil column is divided into two layers, with the upper layer representing the dynamic root zone. The resulting ability to account for changes in root-zone water storage allows for implementation at the monthly timescale. This new version of the Eagleson model is coined the Statistical-Dynamical Ecohydrology Model (SDEM). The ability of the SDEM to capture the seasonal dynamics of the local-scale soil-water balance is demonstrated for two grassland sites in the US Great Plains. Sensitivity of the results to variations in peak green leaf area index (LAI) suggests that the mean peak green LAI is determined by some minimum in root zone soil moisture during the growing season. That minimum appears to be close to the soil matric potential at which the dominant grass species begins to experience water stress and well above the wilting point, thereby suggesting an ecological optimality hypothesis in which the need to avoid water-stress-induced leaf abscission is balanced by the maximization of carbon assimilation (and associated transpiration). Finally, analysis of the sensitivity of model-determined peak green LAI to soil texture shows that the coupled model is able to reproduce the so-called "inverse texture effect", which consists of the observation that natural vegetation in dry climates tends to be most productive in sandier soils despite their lower water holding capacity. Although the determination of LAI based on complete or near-complete utilization of soil moisture is not a new approach in ecohydrology, this paper demonstrates its use for the first time with a new monthly statistical-dynamical model of the water balance. Accordingly, the SDEM provides a new framework for studying the controls of soil texture and climate on vegetation density and evapotranspiration.
Comparison of the fall rate and structure of recent T-7 XBT manufactured by Sippican and TSK
Authors: Kizu S. , Sukigara C. , Hanawa K.
Published: October 2010

Abstract. The fall rate of recent T-7 expendable bathythermograph (XBT) is evaluated based on a series of concurrent measurement with a calibrated Conductivity Temperature Depth profiler (CTD) in the sea east of Japan. An emphasis is placed on comparing the fall rates of T-7 produced by the two present manufacturers, the Lockheed Martin Sippican Inc., and the Tsurumi Seiki Co. Ltd., which have been believed to be identical but had never been compared directly. It is found that the two manufacturers' T-7 fall at rates different by about 3.5%. The Sippican T-7 falls slower than the current standard equation by Hanawa et al. (1995) gives by about 2.1%, and the TSK T-7 falls faster than it tells by about 1.4%. The fall-rate coefficients estimated based on the present sea test by applying the equation of traditional quadratic form, d(t)=at−bt2 where d is depth in meters and t is the time elapsed, since the water entry of the probe, in seconds, are a=6.553 and b=0.00221 for the LMS T-7, and a=6.803 and b=0.00242 for the TSK T-7. By detail examination of the probes, it is revealed that the two companies' T-7 have different total weight and many structural differences. Because the difference in the fall rate is about twice larger than the difference in weight (about 2%), it is inferred that those structural differences give sizable impact to the difference in their fall rates. Our results clearly show that the recent T-7 of the two companies needs to be discriminated.
Assessing the Impact of Zero Tilled Wheat Growing in Rice (Oryza Sativa L.)–Wheat (Triticum Aestivum L.) Cropping Systems
Authors: Singh S.N. , Sah A.K. , Prakash Om , Singh R.K. , Singh V.K.
Published: October 2010

Rice–wheat is the most commonly employed cropping system on around 14 million hectares of land extending across the Indo-Gangetic Plain (IGP). The IGP region covers the South Asian countries of Pakistan (2.2 million ha), India (10.5 million ha), Nepal (0.5 million ha) and Bangladesh (0.8 million ha). The major challenge facing the IGP's rice–wheat cropping system is to sustain long-term productivity. This system has a pivotal role in the food security and livelihoods of millions of farmers and workers of populous countries such as India, particularly in central Uttar Pradesh. The system's productivity and economic gains have been consistently decreasing, mainly because of the delayed sowing of wheat after the rice harvest and the fatigued soil condition. The region's farmers lose valuable time for pre-sowing irrigation and field preparation due to the gap of two to three weeks between the harvesting of rice and the planting of wheat. If wheat sowing is delayed beyond the optimal time (by late November), yields plummet at the rate of 30 kg per ha per day. The adoption of resource conservation technologies, such as zero tilled wheat sowing, is considered essential to maintain the productivity of the rice–wheat cropping system. Economic analysis of data for two years from six on-farm demonstrations shows that the zero tillage method of wheat cultivation is the most economical and attractive option for the farming community of central Uttar Pradesh. A high grain yield and reduced cost of cultivation per hectare, reduction in the density of weeds, especially Phalaris minor, and greater water saving were noted in zero tilled wheat sowings compared with conventional practices. As a result of field demonstrations and farmer training programmes, the introduction of zero till drill wheat sowing has expanded rapidly and has made significant contributions to the tillage revolution in the study area.
Hepatitis C virus–associated polyarteritis nodosa
Authors: Saadoun D. , Terrier B. , Semoun O. , Sene D. , Maisonobe T. , Musset L. , Amoura Z. , Rigon M. Resche , Cacoub P.
Published: October 2010

Objective

To analyze the main characteristics and outcome of polyarteritis nodosa (PAN)–type vasculitis associated with hepatitis C virus (HCV).

Methods

We reported the characteristics and outcome of 31 patients chronically infected with HCV who satisfied the American College of Rheumatology and Chapel Hill criteria for PAN, seen between 1990 and 2009 in a university center.

Results

Among a cohort of 161 patients with HCV‐related vasculitis, 31 (19.3%) were diagnosed as having PAN. The median age was 64.5 years (interquartile range 49.5–70.5 years), with 54.8% women. Compared with HCV‐associated mixed cryoglobulinemia (HCV‐MC) vasculitis, HCV‐PAN displayed a more severe and acute clinical presentation with more frequent fever and weight loss (P < 0.0001), severe hypertension (P = 0.0006), gastrointestinal tract involvement (P < 0.0001), severe acute sensory‐motor multifocal mononeuropathy (P < 0.0001), kidney and liver microaneurysms (P = 0.002), and increased C‐reactive protein level (P < 0.0001). Complete clinical remission of vasculitis was achieved in 79.3% of HCV‐PAN patients compared to 57.5% of HCV‐MC patients (P = 0.05). In multivariate analysis, skin involvement (odds ratio [OR] 2.81, 95% confidence interval [95% CI] 1.27–6.33) and PAN‐type vasculitis (OR 3.01, 95% CI 1.16–8.96) were independently associated with a complete clinical response of HCV vasculitis. A glomerular filtration rate <70 ml/minute (OR 0.54, 95% CI 0.24–1.21) was negatively associated with a complete clinical response of HCV vasculitis. The 5‐year survival rate was 86% in the entire cohort, regardless of the vasculitis type.

Conclusion

HCV‐PAN accounts for 19.3% of our cohort of HCV vasculitis. HCV‐PAN displays a more severe and acute clinical presentation and a higher rate of clinical remission.
The First Decarbonylative Coupling of Aldehydes and Norbornenes Catalyzed by Rhodium
Authors: Yang Luo , Guo Xiangyu , Li Chao‐Jun
Published: October 2010

The decarbonylative coupling of aldehydes and norbornene analogues was realized for the first time by using a rhodium(I) catalyst.
Towards Greener Fluorine Organic Chemistry: Direct Electrophilic Fluorination of Carbonyl Compounds in Water and Under Solvent‐Free Reaction Conditions
Authors: Stavber Gaj , Stavber Stojan
Published: October 2010

Selective and efficient fluorination of organic 1,3‐dicarbonyl compounds was achieved using the electrophilic fluorinating reagentsSelectfluorTMF‐TEDA‐BF4(1‐chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo[2.2.2]octane bis‐tetrafluoroborate) in aqueous medium orAccufluorTMNFSi(N‐fluorobenzenesulfonimide) under solvent‐free reaction conditions (SFRC). Under both reaction conditions cyclic 1,3‐dicarbonyl compounds were transformed into 2‐fluoro‐substituted derivatives and acyclic analogues into 2,2‐difluoro‐substituted compounds, while the reactions of 1‐trifluoromethyl‐substituted 1,3‐dicarbonyls in water resulted in the formation of 2,2‐difluoro‐3,3‐dihydroxy‐1‐one derivatives. The reactivity of the starting material in water was found to be dependent on its enolizability, hydrophobic interactions and aggregate state at the reaction temperature. Reactions under SFRC proceeded in the molten eutectic phase of the reactants. The technique of competitive reactivity was used in order to evaluate and better understand the effects of reaction conditions on the course of these reactions.
Recyclable Polymer‐Supported Iodobenzene‐Mediated Electrocatalytic Fluorination in Ionic Liquid
Authors: Sawamura Takahiro , Kuribayashi Shunsuke , Inagi Shinsuke , Fuchigami Toshio
Published: October 2010

The electrochemical fluorination of organosulfur compounds in triethylamine/hydrofluoric acid (Et3N‐5 HF) with polystyrene‐supported iodobenzene (PSIB) and tetraethylammonium chloride (Et4NCl) was performed successfully in an undivided cell under constant current conditions to afford the corresponding fluorinated compounds in moderate to good yields. Recycle use of the PSIB could be achieved due to its easy separation. Notably, the mediatory activity of the iodobenzene derivative was not appreciably changed even after 10 recycle uses.