bluuebunny/crossref_metadata_2025 huggingface dataset:
Regioselective 2‐Imino‐1,3‐thiazolidine vs. 2‐Imino‐1,3‐oxazolidine Formation from the Vicinal sec‐Amino Alcohol of Desosamine
Authors: Ištuk Zorica Marušić , Vujasinovi Ines , Čikoš Ana , Kragol Goran
Published: June 2013

In order to optimize Mukaiyama reagent‐induced cyclization of vicinal sec‐amino alcohols of desosamine origin towards exclusive formation of N′‐substituted‐2‐imino‐1,3‐thiazolidines via a thiocarbamoyl intermediate, the influence of reaction conditions was studied. A novel, mild, one‐pot, two‐step method was developed, and the formation of N′‐substituted‐2‐imino‐1,3‐oxazolidines as side products was minimized. The inversion of configuration at C‐2′ was unambiguously established using NMR‐based conformational analysis. A reaction mechanism was proposed. A test series of novel desosamine‐modified 14‐ and 15‐membered macrolides, bearing N′‐alkyl‐2‐imino‐1,3‐thiazolidines fused to the desosamine sugar were prepared.
Protocols for the Catalytic Oxidation of Primary Amines to Imines
Authors: Largeron Martine
Published: June 2013

The catalytic oxidation of amines to imines is of intense current interest, owing to the importance of imines as pivotal intermediates in the synthesis of fine chemicals and numerous biologically active compounds. Whereas considerable efforts had been made to develop efficient methods for the oxidation of secondary amines to imines, little attention had until recently been given to the oxidation of primary amines, probably because the generated imines are intermediate products that are easily dehydrogenated to nitriles. A surge of activity in this area originated with the discovery of new catalytic systems that allow the oxidation of primary amines to imines under green conditions. This microreview focuses on the major achievements during the last five years.
Photochemical and Thermal [2 + 2] Cycloaddition to Generate the Bicyclo[3.2.0]­hept­ane Core of Bielschowskysin
Authors: Farcet Jean‐Baptiste , Himmelbauer Martin , Mulzer Johann
Published: June 2013

A bicyclic core fragment of the marine diterpenoid bielschowskysin has been synthesized. First, a large library of precursors for a photochemical [2 + 2] cycloaddition was prepared and tested, but with limited success. In the end, a thermal [2 + 2] cycloaddition followed by appropriate regio‐ and stereocontrolled functionalization efficiently gave access to the desired bicyclo[3.2.0]heptane core. An optimized route to this remarkable molecular structure is presented.
Rearrangements of Furan‐, Thiophene‐ and N‐Boc‐Pyrrole‐Derived Donor‐Acceptor Cyclopropanes: Scope and Limitations
Authors: Kaschel Johannes , Schneider Tobias F. , Schirmer Patrick , Maaß Christian , Stalke Dietmar , Werz Daniel B.
Published: June 2013

Rearrangements of furan‐, thiophene‐ and N‐Boc‐pyrrole‐derived donor–acceptor cyclopropanes initiated by Brønsted acids were investigated. Throughout the study, ketones or aldehydes were utilized as accepting moieties and oxygen, sulfur and Boc‐protected nitrogen were used as the donor atoms. Whether a ring‐enlargement and thus an annelation of a five‐membered ring, or a ring‐opening of the three‐membered ring followed by rearomatization to the parent heterocycles takes place strongly depends on the substitution pattern of the cyclopropane. Commonly, more substituted substrates led to annelation whereas less substituted substrates tend to undergo rearomatization. In general, good yields were obtained for starting materials with oxygen and nitrogen donors, whereas the reactions with sulfur as donor gave only poor yields.
Synthesis, Chiral Resolution, and Absolute Configuration of Dissymmetric 4,12‐Difunctionalized [2.2]Paracyclophanes
Authors: Meyer‐Eppler Georg , Vogelsang Elisabeth , Benkhäuser Christian , Schneider Andreas , Schnakenburg Gregor , Lützen Arne
Published: June 2013

Racemic 4,12‐difunctionalized [2.2]paracyclophanes were synthesized and successfully resolved by (recycling) HPLC on a stationary CHIRALPAK IA phase at a semipreparative scale. Their absolute configurations were determined by X‐ray crystal structure analysis and/or by comparison of their specific optical rotations with literature data. These are valuable functionalized C2‐symmetric building blocks for the formation of more sophisticated V‐shaped, chiral molecular architectures, as demonstrated by some exploratory transformations.
Total Synthesis of the Hypermodified tRNA Nucleoside Epoxyqueuosine
Authors: Thoma Ines , Carell Thomas
Published: June 2013

Queuosine is one of the most strongly modified nucleosides found in transferRNA (tRNA) of almost all species. Queuosine is found exclusively in the wooble position of the anticodon loop of several tRNA, where it is involved in tRNAAsp, tRNAAsn tRNAHis, and tRNATyr. The biosynthesis of queuosine is performed by prokaryotes, and eukaryotes are fully dependent on this external source. To investigate the interesting biosynthesis of the Q base, we report here the first total synthesis of the direct biosynthetic precursor oQ. By using LC–MS in combination with special E. coli growing conditions (no vitamin B12 in the medium) we confirm the structure of the oQ natural products.
Long‐Term Forecasting of Global Carbon Dioxide Emissions: Reducing Uncertainties Using a Per Capita Approach
Authors: Mckitrick Ross , Strazicich Mark C. , Lee Junsoo
Published: June 2013

Global CO2 emission forecasts span such a wide range as to yield little guidance for climate policy and analysis. But global per capita emissions appear to be better constrained than total emissions, which we argue has an economic justification. Trend stationarity of per capita emissions may provide a means of characterizing the relative likelihood of global forecasts. On data spanning 1950 to 2009 a unit root hypothesis allowing for endogenous structural breaks is rejected, but adding in the 2010 observation pushes the p‐value slightly over 0.1. Since structural breaks cannot be detected at the end of sample this may simply indicate a power problem. Using Monte Carlo simulations we conclude that the lower half of a well‐known suite of IPCC emission scenarios is more likely to occur than the upper half, and the top quartile is particularly difficult to justify. Copyright © 2013 John Wiley & Sons, Ltd.
The Role of High‐Frequency Intra‐daily Data, Daily Range and Implied Volatility in Multi‐period Value‐at‐Risk Forecasting
Authors: Louzis Dimitrios P. , Xanthopoulos‐Sisinis Spyros , Refenes Apostolos P.
Published: June 2013

This paper assesses the informational content of alternative realized volatility estimators, daily range and implied volatility in multi‐period out‐of‐sample Value‐at‐Risk (VaR) predictions. We use the recently proposed Realized GARCH model combined with the skewed Student's t distribution for the innovations process and a Monte Carlo simulation approach in order to produce the multi‐period VaR estimates. Our empirical findings, based on the S&P 500 stock index, indicate that almost all realized and implied volatility measures can produce statistically and regulatory precise VaR forecasts across forecasting horizons, with the implied volatility being especially accurate in monthly VaR forecasts. The daily range produces inferior forecasting results in terms of regulatory accuracy and Basel II compliance. However, robust realized volatility measures, which are immune against microstructure noise bias or price jumps, generate superior VaR estimates in terms of capital efficiency, as they minimize the opportunity cost of capital and the Basel II regulatory capital. Copyright © 2013 John Wiley & Sons, Ltd.
Research into the functional components and antioxidant activities of North China rice wine (Ji Mo Lao Jiu)
Authors: He Shuai , Mao Xiangzhao , Liu Pei , Lin Hong , Du Zuyuan , Lv Ning , Han Jichen , Qiu Cuifang
Published: June 2013

Over the last decade, considerable experimental evidence has supported the view that grape wine and South China rice wine are rich in diverse nutrients and have powerful antioxidant activity. However, little research has been carried out for North China rice wine, of which Ji Mo Lao Jiu (JMLJ) is the outstanding representative. In this study, the functional components and antioxidant activity of JMLJ were investigated. Twenty‐eight free amino acids were found in JMLJ, much more than that previously reported in other Chinese rice wines (16–21). Functional oligosaccharides (5290.222 mg/L), total phenols (722.431 ± 10.970 mg/L), and mineral elements (9) were rich in JMLJ. When compared with synthetic antioxidants, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), JMLJ showed effective 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) radical scavenging and reducing capacity. The results of this study lay the foundation for promoting the utilization of JMLJ and the development of North China rice wine in the food industry.
Erweiterte Einsatzbereiche von EPB‐Schilden
Authors: Budach Christoph , Thewes Markus
Published: June 2013

Zur Erweiterung der Einsatzbereiche von Erddruckschilden auf gemischtkörnige Lockergesteine mit geringem Feinanteil sowie auf grobkörnige Böden hat sich die Konditionierung des abgebauten Materials mit Schäumen, Polymeren und Feinstoffsuspensionen als effektiv erwiesen. Auf diese Weise können die Eigenschaften des Stützmediums in der Abbaukammer eines Erddruckschilds so verändert werden, dass z.B. die Fließfähigkeit sowie die Durchlässigkeit günstig beeinflusst werden. Bisherige Veröffentlichungen zu den Einsatzgrenzen von Erddruckschilden, insbesondere in grobkörnigen Böden, sind vielfach durch die empirische Auswertung von Baustellenerfahrungen geprägt. In den hier vorgestellten Untersuchungen erfolgte dagegen eine breite und systematische Variation von Kornverteilungen grob‐ und gemischtkörniger Böden, die mit Schäumen, Polymeren sowie Feinstoffsuspensionen konditioniert wurden. Die Laboruntersuchungen mit den konditionierten Böden betrafen insbesondere die Kriterien der Verarbeitbarkeit und der Wasserdurchlässigkeit. Unter Berücksichtigung praxisnaher Vorgaben für diese Kriterien konnte ein modifiziertes Kornverteilungsdiagramm für die Einsatzbereiche von Erddruckschilden entwickelt werden.

Extended Application Ranges of EPB‐Shields. Soil conditioning for Earth‐Pressure‐Balance shield tunnelling with foams, polymers or high density slurries has proven to be an effective measure to extend the application ranges of EPB‐Shields towards mixed‐grained soils with a low content of fines and coarse‐grained soils. By conditioning, the properties of the support medium in the excavation chamber, which mainly consists of the excavated ground, can be changed in order to positively influence i.e. its deformability and permeability. Acknowledging existing results of research on EPB conditioning a new investigation programme was developed, which aimed at a broad and systematic variation of coarse soil types as well as conditioning agents. Based on the results of the laboratory research, a chart for the application ranges for EPB‐Shields using various conditioning agents was developed, which shows some significant differences to the existing empirical charts that by large are based on job site experience.
Resilience: A Meta‐Analytic Approach
Authors: Lee Ji Hee , Nam Suk Kyung , Kim A‐Reum , Kim Boram , Lee Min Young , Lee Sang Min
Published: June 2013

This study investigated the relationship between psychological resilience and its relevant variables by using a meta‐analytic method. The results indicated that the largest effect on resilience was found to stem from the protective factors, a medium effect from risk factors, and the smallest effect from demographic factors.
Research Quality: Critique of Quantitative Articles in the Journal of Counseling & Development
Authors: Wester Kelly L. , Borders L. DiAnne , Boul Steven , Horton Evette
Published: June 2013

The purpose of this study was to examine the quality of quantitative articles published in the Journal of Counseling & Development. Quality concerns arose in regard to omissions of psychometric information of instruments, effect sizes, and statistical power. Type VI and II errors were found. Strengths included stated research questions and appropriateness of analyses. Implications of these results are provided.
Attachment, Autonomy, and Emotional Reliance: A Multilevel Model
Authors: Lynch Martin F.
Published: June 2013

This article reports a test of a multilevel model investigating how attachment security and autonomy contribute to emotional reliance, or the willingness to seek interpersonal support. Participants (N = 247) completed online measures of attachment, autonomy, emotional reliance, and vitality with respect to several everyday relationships. Multilevel model analyses identified a within‐person process linking emotional reliance and vitality with both attachment and autonomy. Discussion focuses on the implications for both counseling and development.
Does Motivational Interviewing (MI) Work With Nonaddicted Clients? A Controlled Study Measuring the Effects of a Brief Training in MI on Client Outcomes
Authors: Young Tabitha L. , Gutierrez Daniel , Hagedorn W. Bryce
Published: June 2013

This study investigated the relationships between motivational interviewing (MI) and client symptoms, attendance, and satisfaction. Seventy‐nine clients attending a university‐based counseling center were purposefully assigned to treatment or control conditions. Statistical analyses revealed client symptoms in both groups improved. However, clients assigned to treatment conditions attended more sessions and missed fewer sessions than clients in the control group. Implications for using MI and suggestions for additional research are explored within the study.
Professional Counseling in Taiwan: Past to Future
Authors: Guo Yuh‐Jen , Wang Shu‐Ching , Combs Don C. , Lin Yi‐Chun , Johnson Veronica
Published: June 2013

Because of the recent introduction of a licensure law, professional counseling has grown rapidly in Taiwan after decades of slow development. The authors provide a historical review of the development of professional counseling in Taiwan and discuss the current status and future trajectory of professional counseling in Taiwan.
From Good to Great: Examining Exemplary Counselor Development
Authors: Henderson Donna A. , Montplaisir Bethany F.
Published: June 2013

Some counselors excel in the profession. Few do so while maintaining a balance in life. This article examines the life of one such individual, Samuel T. Gladding. He models for counselors an aspirational process of making significant contributions to the profession while staying personally grounded. Qualities that propel professionals like Gladding from being good as a young professional into prominence as a mature counselor are examined.
Trends and Implications of Proposed Changes to the DSM‐5 for Vulnerable Populations
Authors: Miller Raissa , Prosek Elizabeth A.
Published: June 2013

The revision process for the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; American Psychiatric Association, 2000) has increased consciousness for the role of diagnosis in counseling. In this article, the authors discuss 3 trends of the proposed changes: the influence of the medical model, the attention to nosology, and lowered thresholds and their potential impact on nondominant populations. Potential implications for reflection and advocacy among counseling professionals are discussed.
Quantitative characterization of mesenchymal stem cell adhesion to the articular cartilage surface
Authors: Hung Ben P. , Babalola Omotunde M. , Bonassar Lawrence J.
Published: June 2013

There has been great interest in use of mesenchymal stem cell (MSC)‐based therapies for cartilage repair. Most recently, treatments involving intra‐articular injection of MSCs have shown great promise for cartilage repair and arthritis therapy, which rely on MSC adhesion to cartilage. While there is some information on chondrocyte adhesion to cartilage, there is relatively little known about the kinetics and strength of MSC adhesion to cartilage. The goals of this study were as follows: (1) to quantify the kinetics and strength of adhesion of marrow‐derived MSCs to articular cartilage using standard laboratory hardware; (2) to compare this adhesion behavior to that of articular chondrocytes; and (3) to assess the effect of serial monolayer culture on MSC adhesion. First through fourth passage MSCs and primary articular chondrocytes were allowed to adhere to the articular surface of cartilage disks for up to 30 h and the number of adhered cells was recorded to quantify adhesion kinetics. After 30 h, adherent cells were subjected to centrifugal shear to determine adhesion strength, quantified as the shear necessary to detach half the adhered cells (σ50). The number of adhered MSCs and adhesion strength increased with passage number and MSCs adhered more strongly than did primary articular chondrocytes. As such, the kinetics and strength of MSC adhesion to cartilage is not dramatically lower than that for articular chondrocytes. This protocol for assessing cell adhesion to cartilage is simple to implement and may represent an important screening tool for assessing the efficacy of cell‐based therapies for cartilage repair. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3592–3598, 2013.
Topographical control of ocular cell types for tissue engineering
Authors: McHugh Kevin J. , Saint‐Geniez Magali , Tao Sarah L.
Published: June 2013

Visual impairment affects over 285 million people worldwide and has a major impact on an individual's quality of life. Tissue engineering has the potential to increase the quality of life for many of these patients by preventing vision loss or restoring vision using cell‐based therapies. However, these strategies will require an understanding of the microenvironmental factors that influence cell behavior. The eye is a well‐organized organ whose structural complexity is essential for proper function. Interactions between ocular cells and their highly ordered extracellular matrix are necessary for maintaining key tissue properties including corneal transparency and retinal lamination. Therefore, it is not surprising that culturing these cells in vitro on traditional flat substrates result in irregular morphology. Instead, topographically patterned biomaterials better mimic native extracellular matrix and have been shown to elicit in vivo‐like morphology and gene expression which is essential for tissue engineering. Herein we review multiple methods for producing well‐controlled topography and discuss optimal biomaterial scaffold design for cells of the cornea, retina, and lens. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1571–1584, 2013.
Cytotoxicity of adhesive systems of different hydrophilicities on cultured odontoblast‐like cells
Authors: Bianchi Luciana , Ribeiro Ana Paula Dias , de Oliveira Carrilho Marcela Rocha , Pashley David H. , de Souza Costa Carlos Alberto , Hebling Josimeri
Published: June 2013

This study evaluated the cytotoxicity of experimental adhesive systems (EASs) on odontoblast‐like cells. Paper discs (n = 132) were impregnated with 10 µL of each EAS—R1, R2, R3, R4, and R5 (in an ascending order of hydrophilicity), followed by photoactivation. R1 and R2 are nonsolvated hydrophobic blends, R3 represents a simplified etch‐and‐rinse adhesive system, and R4 and R5 represent simplified self‐etch adhesive systems. Discs were immersed in Dulbecco's modified Eagle's medium for 24 h to obtain eluates applied on MDPC‐23 cell cultures. No material was applied on discs used as control (R0). Cell viability [3‐(4,5‐dimethythiazol‐2‐yl)−2,5‐diphenyl tetrazolium bromide assay], total protein (TP) production, alkaline phosphatase (ALP) activity, type of cell death, and degree of monomer conversion Fourier transform infrared (%DC‐FTIR) were evaluated. Data were analyzed by Kruskal–Wallis and Mann–Whitney tests (α = 0.05). Considering R0 (control) as having 100% of cell viability, R1, R2, R3, R4, and R5 reduced the metabolic activity of cells by 36.4, 3.1, 0.2, 21.5, and 65.7%, respectively, but only R1 and R5 differed from R0. Comparing with R0, lower TP production was observed for R1, R4, and R5, while ALP activity decreased for R1 and R5. Necrotic cell death was predominant for all EASs, but only R1, R4, and R5 differed from R0. Only R5 presented a different apoptotic cell death ratio from R0. R1 presented the lowest %DC (ca. 37%), whereas R4 and R5 presented the highest (ca. 56%). In conclusion, R2 and R3 were not toxic to the MDPC‐23 cells, suggesting that the degree of hydrophilicity or %DC of the EASs alone were not responsible for their cytopathic effects. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1498–1507, 2013.
Coaxial electrospinning of P(LLA‐CL)/heparin biodegradable polymer nanofibers: potential vascular graft for substitution of femoral artery
Authors: Zhai Wei , Qiu Li‐jun , Mo Xiu‐mei , Wang Sheng , Xu Yun‐fei , Peng Bo , Liu Min , Huang Jun‐hua , Wang Guang‐chun , Zheng Jun‐hua
Published: June 2013

Electrospinning is one of the most simple and effective methods to prepare polymer fibers with the diameters ranging from nanometer to several micrometers. Poly(L‐lactide)‐co‐poly (ɛ‐caprolactone) (P(LLA‐CL)) fibers and P(LLA‐CL)/heparin coaxial composite fibers herein were successfully prepared by single electrospinning and coaxial electrospinning, respectively. The prepared endothelialized P(LLA‐CL) and P(LLA‐CL)/heparin vascular grafts were used in the Beagle dogs experiment to evaluate the feasibility of thus made different scaffolds for substitution of dog femoral artery in early period, medium term, and long term, meanwhile the pure P(LLA‐CL) vascular graft was used as the control group during all the experiments. The animal model was established by using the graft materials to anastomose both femoral arteries of dogs. The vascular grafts patency rates (i.e., the unobstructed capacity of blood vessel) were detected by color Doppler flow imaging technology and digital subtraction angiography. To observe the histological morphology at different periods, the vascular grafts were removed after 7, 14, and 30 days, and the corresponding histological changes were evaluated by hematoxylin and eosin staining. The experimental results show that in the early period, the patency rates of pure P(LLA‐CL) graft, endothelial P(LLA‐CL) graft, and P(LLA‐CL)/heparin graft were 75%, 75%, and 100%, respectively; in the medium term, the patency rates of pure P(LLA‐CL) graft and endothelial P(LLA‐CL) graft were 25%, whereas that of P(LLA‐CL)/heparin graft was 50%; the patency rates of pure P(LLA‐CL) graft and endothelial P(LLA‐CL) graft were down to 0%, whereas the patency rate of P(LLA‐CL)/heparin graft was 25% in the long term. This preliminary study has demonstrated that P(LLA‐CL)/heparin coaxial composite fiber maybe a reliable artificial graft for the replacement of femoral artery. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 471–478, 2019.
Quantitation of cholesterol and phospholipid sorption on silicone hydrogel contact lenses
Authors: Pitt William G. , Perez Krystian X. , Tam Ngai Keung , Handly Erika , Chinn Joseph A. , Liu Xiaojun Michael , Maziarz Edmond Peter
Published: June 2013

The introduction of silicone hydrogel (SiHy) contact lenses to the consumer marketplace necessitates study of the susceptibility of these lenses to spontaneous deposition by hydrophobic lipid components of ocular tears. The use of radioisotopes to measure lipid sorption on SiHy contact lenses gives precise and accurate results but requires institutional infrastructure and compels efficient lipid removal from the lens. This study compares three methods of quantitating phospholipid and cholesterol sorption on SiHy lenses using radiolabeled cholesterol and phosphatidylcholine that were sorbed on lenses from an artificial tear fluid. A triple extraction technique using n‐propanol gives the most reliable results. Comparison of sorption on SiHy lenses shows that balafilcon A and senofilcon A lenses sorb similar amounts, while lotrafilcon B lenses sorb comparatively less. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1516–1523, 2013.
Quantitative characterization of porous commercial and experimental bone graft substitutes with microcomputed tomography
Authors: Ylä‐Soininmäki Anne , Moritz Niko , Turco Gianluca , Paoletti Sergio , Aro Hannu T.
Published: June 2013

A large number of resorbable bone graft substitutes are being marketed as porous, but the total porosity being referred does not take into account many of the biologically important physical aspects of porosity. Therefore, to allow the direct comparison of different commercial products, there is a need to adopt guidelines for a standardized characterization. The aim of the study was to assess a microcomputed tomography‐based method for the characterization of porous biomaterials to allow head‐to‐head comparison of these materials. The study included two commercial biomaterials (Actifuse® and ChronOs®) and three experimental biomaterials (sintered bioactive glass microspheres, porous alginate (Alg), and porous Alg/hydroxyapatite composite). In addition to porosity and pore size distributions, the interconnectivity of the pores was assessed by an iterative blocking of interconnections. The biomaterials were characterized in their original morphologies (granules or cones). Differences between the materials were demonstrated. Actifuse® had the broadest distributions of pores and interconnections. ChronOs® had a substantial fraction of closed pores (10%). Other materials had closed porosity below 1%. Due to the thinner walls of the lattice, the Alg‐based materials had high total porosity (>80%). Discrepancies were found between the porosity values reported by the manufacturers and the values obtained in this study. The proposed method is plausible for the systematic characterization of porous biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1538–1548, 2013.
Effectiveness of novel xylanases belonging to different GH families on lignin and hexenuronic acids removal from specialty sisal fibres
Authors: Valenzuela Susana Valeria , Valls Cristina , Roncero M. Blanca , Vidal Teresa , Diaz Pilar , Pastor F.I. Javier
Published: June 2013

BACKGROUND

The effectiveness of xylanases on lignin removal from pulps differs widely depending on the enzyme family, the type of pulp and the bleaching sequence among other factors. Xylanases can also reduce the presence of undesirable hexenuronic acids in the papermaking fibers. The performance of non‐commercial xylanases belonging to families GH10, GH30, GH30‐CBM35 and GH11, and of the multicomponent xylanase from Paenibacillus barcinonensis for lignin and hexenuronic acids removal from sisal (Agave sisalana) has been evaluated.

RESULTS

Sisal pulps were bleached by an XP sequence, where X denotes the enzyme treatment and P a hydrogen peroxide extraction stage. Kappa number, brightness, viscosity and hexenuronic acid content of samples were determined. Sugars released from sisal pulps, other non‐wood fibres and also eucalyptus fibres, by the treatment with xylanases were also analysed. The best results were obtained with the GH10 xylanase and with crude supernatants of P. barcinonensis, which produced a lignin removal of 23% and a reduction of 25% in the hexenuronic acid content of sisal pulps without a significant loss of viscosity.

CONCLUSION

The release of sugars in the effluents from the X stage applied to sisal correlated with the effectiveness of the xylanases tested. The xylan content of wood and non‐wood fibres, the type of xylan and its accessibility also had an influence on the xylanase activity on pulps. © 2013 Society of Chemical Industry
Mixed matrix membranes for process intensification in electrodialysis of amino acids
Authors: Kattan Readi O. M. , Rolevink E. , Nijmeijer K.
Published: June 2013

BACKGROUND

Amino acids are valuable intermediates in the biobased economy for the production of chemicals. Electro‐membrane processes combined with enzymatic modification have been investigated as an alternative technology for the fractionation of a mixture of amino acids with almost identical charge behavior. Up to now, the modification and subsequent separation were performed in two separate reactors. An interesting approach is the integration of both unit operations into one single device using mixed matrix membranes (MMMs) as platform for enzymatic conversion.

RESULTS

MMMs containing the enzyme glutamic acid decarboxylase (GAD, EC 4.1.1.15) Relizyme EP403/S as carrier were prepared showing satisfactory mechanical stability and enzymatic activity for L‐glutamic acid conversion into γ‐aminobutyric acid (GABA). ED with integrated MMM for simultaneous enzymatic decarboxylation of L‐glutamic acid to GABA (33% conversion) and further separation of L‐aspartic acid and unconverted L‐glutamic acid from GABA was successful leading to current efficiency of 40% and low energy consumption of 3 kWh kg‐1.

CONCLUSIONS

Together with the high mechanical stability obtained for the MMMs, this opens the route towards process intensification, combining enzymatic conversion and separation with electrodialysis in one integrated process for the successful isolation of amino acids for biorefinery applications. © 2013 Society of Chemical Industry
Photoreduction of nitrogen trifluoride with controlled release of radicals
Authors: Liu Xingang , Zhang Jiahui , Zhang Renxi , Hou Huiqi , Chen Shanping , Zhang Yi
Published: June 2013

BACKGROUND

With the rapid growth of the semiconductor and thin film transistor liquid crystal display manufacturing industries, large quantities of the potent greenhouse gas nitrogen trifluoride (NF3) is in demand. But perfluorocarbons are very stable compounds because of their molecular structures. Therefore, in the atmosphere, NF3 is difficult to oxidize by O3, NO, NO2, and OH radicals, except by excited oxygen atoms O(1D) that can react with it to form NF2 or other products. In this study the possible degradation process of NF3 in the ‘controlled release of radicals’ reactor is discussed.

RESULTS

Under the conditions of 5 mmHg partial pressure of NF3 and 600 mmHg total pressure with buffer gas of argon, NF3 was photodegraded in an in situ reactor with a ‘controlled release of radicals’ system. The results indicated that reductive double bonds and allyl radicals, slowly released from polyisoprene irradiated by a UV lamp emitting 185 and 253.7 nm of light, could contribute to the NF3 degradation in the CRR system. The NF3 degradation efficiency, significantly affected by O2 and almost independent of N2, reached 96% with a kinetic rate constant k ≈ 1.77 × 10−4 s−1 after 300 min of ultraviolet irradiation.

CONCLUSION

According to the experimental results, a potential way of continuous photoreduction of NF3 was found, since excited double bonds and allyl radicals are consequently released by irradiating the surface of the polymer matrix. The considerable degradation reaction constant of NF3 and no fluoride byproducts in gas make it possible for industry application. © 2013 Society of Chemical Industry
Equatorial zonal plasma drifts measured by the C/NOFS satellite during the 2008–2011 solar minimum
Authors: Fejer Bela G. , Tracy Brian D. , Pfaff Robert F.
Published: June 2013

We use the measurements by the Vector Electric Field Investigation (VEFI) on board the Communication/Navigation Outage Forecasting System (C/NOFS) satellite to study the local time and seasonal‐ and longitudinal‐dependent climatology of equatorial F region zonal plasma drifts during 2008–2011. These drifts are essentially westward during the day and eastward at night. Over Jicamarca Radio Observatory, the satellite measurements are in good agreement with incoherent scatter radar drifts. Our data show strong longitudinal variations, particularly in the South American sector during the solstices. The equinoctial data exhibit short‐lived and largely enhanced westward drifts near sunrise and wave‐4 structures from the early afternoon to late night equinoctial periods. The nighttime eastward drifts are largest near the western American sector at all seasons. The June solstice postmidnight eastward drifts decrease sharply at longitudes of about 310° and have much smaller values in the entire Eastern Hemisphere. We also briefly discuss the relationship between the longitude‐dependent vertical and zonal plasma drifts.
Saturn suprathermal O2+ and mass‐28+ molecular ions: Long‐term seasonal and solar variation
Authors: Christon S. P. , Hamilton D. C. , DiFabio R. D. , Mitchell D. G. , Krimigis S. M. , Jontof‐Hutter D. S.
Published: June 2013

Suprathermal singly charged molecular ions, O2+ (at ~32 Da/e) and the Mass‐28 ion group 28M+ (ions at ~28 Da/e, with possible contributions from C2H5+, HCNH+, N2+, and/or CO+), are present throughout Saturn's ~4–20 Rs (1 Saturn radius, Rs = 60,268 km) near‐equatorial magnetosphere from mid‐2004 until mid‐2012. These ~83–167 keV/e heavy ions measured by Cassini's CHarge‐Energy‐Mass Spectrometer have long‐term temporal profiles that differ from each other and differ relative to the dominant water group ions, W+ (O+, OH+, H2O+, and H3O+). O2+/W+, initially ~0.05, declined steadily until equinox in mid‐2009 by a factor of ~6, and 28M+/W+, initially ~0.007, declined similarly until early‐2007 by a factor of ~2. The O2+/W+ decline is consistent with Cassini's in situ ring‐ionosphere thermal ion measurements, and with proposed and modeled seasonal photolysis of Saturn's rings for thermal O2 and O2+. The water ice‐dominated main rings and Enceladus plume depositions thereon are the two most likely O2+ sources. Enceladus' dynamic plumes, though, have no known long‐term dependence. After declining, O2+/W+ and 28M+/W+ levels remained low until late‐2011 when O2+/W+ increased, but 28M+/W+ did not. The O2+/W+ increase was steady and became statistically significant by mid‐2012, indicating a clear increase after a decline, that is, a possibly delayed O2+ “seasonal” recovery. Ring insolation is driven by solar UV flux which itself varies with the sun's 11 year activity cycle. The O2+/W+ and 28M+/W+ declines are consistent with seasonal ring insolation. No O2+/W+ response to the late‐2008 solar‐cycle UV minimum and recovery is evident. However, the O2+/W+ recovery from the postequinox baseline levels in late‐2011 coincided with a strong solar UV enhancement. We suggest a scenario/framework in which the O2+ observations can be understood.
Optical studies of rocket exhaust trails and artificial noctilucent clouds produced by Soyuz rocket launches
Authors: Dalin P. , Perminov V. , Pertsev N. , Dubietis A. , Zadorozhny A. , Smirnov A. , Mezentsev A. , Frandsen S. , Grønne J. , Hansen O. , Andersen H. , McEachran I. , McEwan T. , Rowlands J. , Meyerdierks H. , Zalcik M. , Connors M. , Schofield I. , Veselovsky I.
Published: June 2013

Detailed tracing of an exhaust plume from a rocket's initial trajectory is a scientifically and diagnostically useful technique. It can provide detailed information on the atmosphere's mean winds, wind shears, turbulent regime, and physical state over a wide altitude range from 50 to 200 km. We analyze Soyuz rocket exhaust plumes from Plesetsk on 21 May 2009 and 27 June 2011, which uncovered significantly different atmospheric states and underlying dynamics. The first case showed highly dynamical conditions in the mesosphere, characterized by vortex structures, wind shears, and small‐scale turbulent eddies. The estimated turbulent energy dissipation rates ranged 330–460 mW kg−1. A characteristic balloon‐shaped trail was observed at altitudes between 105 and 160 km, having rapid expansion rates of 500–800 m s−1 over the time period of 2 min which can be explained by complex gas dynamic processes in the rocket wake involving the collision of shock waves. In the second case, we show evidence that the rocket exhaust trail persisted without any changes during its motion from Plesetsk via Denmark to the UK for 9 h, indicating extremely stable atmospheric conditions. This case introduces a new state of the summer mesosphere—remarkably quiet conditions, probably never observed before. The rocket plumes studied, related to the initial rocket trajectory, are essentially twilight phenomena as seen from the ground using wideband spectrum cameras, that is, the Sun should be below the horizon by 6°. For the first time, we analyze the dynamics of rocket exhaust products at the initial trajectory in the mesosphere and lower thermosphere using detailed photographic imaging taken from the ground.
Top‐down isoprene emissions over tropical South America inferred from SCIAMACHY and OMI formaldehyde columns
Authors: Barkley Michael P. , Smedt Isabelle De , Van Roozendael Michel , Kurosu Thomas P. , Chance Kelly , Arneth Almut , Hagberg Daniel , Guenther Alex , Paulot Fabien , Marais Eloise , Mao Jingqiu
Published: June 2013

We use formaldehyde (HCHO) vertical column measurements from the Scanning Imaging Absorption spectrometer for Atmospheric Chartography (SCIAMACHY) and Ozone Monitoring Instrument (OMI), and a nested‐grid version of the GEOS‐Chem chemistry transport model, to infer an ensemble of top‐down isoprene emission estimates from tropical South America during 2006, using different model configurations and assumptions in the HCHO air‐mass factor (AMF) calculation. Scenes affected by biomass burning are removed on a daily basis using fire count observations, and we use the local model sensitivity to identify locations where the impact of spatial smearing is small, though this comprises spatial coverage over the region. We find that the use of the HCHO column data more tightly constrains the ensemble isoprene emission range from 27–61 Tg C to 31–38 Tg C for SCIAMACHY, and 45–104 Tg C to 28–38 Tg C for OMI. Median uncertainties of the top‐down emissions are about 60–260% for SCIAMACHY, and 10–90% for OMI. We find that the inferred emissions are most sensitive to uncertainties in cloud fraction and cloud top pressure (differences of ±10%), the a priori isoprene emissions (±20%), and the HCHO vertical column retrieval (±30%). Construction of continuous top‐down emission maps generally improves GEOS‐Chem's simulation of HCHO columns over the region, with respect to both the SCIAMACHY and OMI data. However, if local time top‐down emissions are scaled to monthly mean values, the annual emission inferred from SCIAMACHY are nearly twice those from OMI. This difference cannot be explained by the different sampling of the sensors or uncertainties in the AMF calculation.
Ice nucleation properties of rust and bunt fungal spores and their transport to high altitudes, where they can cause heterogeneous freezing
Authors: Haga D. I. , Iannone R. , Wheeler M. J. , Mason R. , Polishchuk E. A. , Fetch T. , van der Kamp B. J. , McKendry I. G. , Bertram A. K.
Published: June 2013

Rust and bunt spores that act as ice nuclei (IN) could change the formation characteristics and properties of ice‐containing clouds. In addition, ice nucleation on rust and bunt spores, followed by precipitation, may be an important removal mechanism of these spores from the atmosphere. Using an optical microscope, we studied the ice nucleation properties of spores from four rust species (Puccinia graminis, Puccinia triticina, Puccinia allii, and Endocronartium harknesssii) and two bunt species (Tilletia laevis and Tilletia tritici) immersed in water droplets. We show that the cumulative number of IN per spore is 5 × 10−3, 0.01, and 0.10 at temperatures of roughly −24°C, −25°C, and −28°C, respectively. Using a particle dispersion model, we also investigated if these rust and bunt spores will reach high altitudes in the atmosphere where they can cause heterogeneous freezing. Simulations suggest that after 3 days and during periods of high spore production, between 6 and 9% of 15 µm particles released over agricultural regions in Kansas (U.S.), North Dakota (U.S.), Saskatchewan (Canada), and Manitoba (Canada) can reach at least 6 km in altitude. An altitude of 6 km corresponds to a temperature of roughly −25°C for the sites chosen. The combined results suggest that (a) ice nucleation by these fungal spores could play a role in the removal of these particles from the atmosphere and (b) ice nucleation by these rust and bunt spores are unlikely to compete with mineral dust on a global and annual scale at an altitude of approximately 6 km.
Concurrent variation between the East Asian subtropical jet and polar front jet during persistent snowstorm period in 2008 winter over southern China
Authors: Liao Zhijie , Zhang Yaocun
Published: June 2013

The concurrent variation features between the East Asian subtropical jet and polar front jet were investigated during persistent snowstorm period in 2007/2008 winter over southern China. The East Asian subtropical jet was divided into two parts: (1) the plateau jet, located along the southern side of the Tibetan Plateau, and (2) the ocean jet, situated at the southeastern Japan Island. The concurrent intensity variation among the polar front jet, plateau jet, and ocean jet and the associated atmospheric anomalous signals were examined. A possible mechanism for concurrent variation among the three jets was also investigated from a perspective of synoptic‐scale transient eddy activities (STEA). The enhanced plateau jet was simultaneously correlated with the weakened polar front jet, while the variation of the ocean jet lagged the variation of the plateau jet (polar front jet) about 5 days. The concurrent variation between the plateau jet and the polar front jet acted as an important bridge that linked the snowstorm to the atmospheric anomalous signals associated with the cold and warm air activities. Due to the opposite trends of STEA variation over the southern and northern sides of the Tibetan Plateau, the plateau jet and the polar front jet exhibited a significant concurrent variation feature. The STEA anomalies over the plateau jet and polar front jet regions propagated downstream to the East Asian coast as a wave train along the southern and northern sides of the Tibetan Plateau, respectively, resulting in a 5 day lag variation relationship between the ocean jet and the plateau jet (polar front jet).
Band‐limited Bouguer gravity identifies new basins on the Moon
Authors: Featherstone W. E. , Hirt C. , Kuhn M.
Published: June 2013

Spectral domain forward modeling is used to generate topography‐implied gravity for the Moon using data from the Lunar Orbiter Laser Altimeter instrument operated on board the Lunar Reconnaissance Orbiter mission. This is subtracted from Selenological and Engineering Explorer (SELENE)‐derived gravity to generate band‐limited Bouguer gravity maps of the Moon so as to enhance the gravitational signatures of anomalous mass densities nearer the surface. This procedure adds evidence that two previously postulated basins on the lunar farside, Fitzgerald‐Jackson (25°N, 191°E) and to the east of Debye (50°N, 180°E), are indeed real. When applied over the entire lunar surface, band‐limited Bouguer gravity reveals the locations of 280 candidate basins that have not been identified when using full‐spectrum gravity or topography alone, showing the approach to be of utility. Of the 280 basins, 66 are classified as distinct from their band‐limited Bouguer gravity and topographic signatures, making them worthy of further investigation.
Regional dynamics of forest canopy change and underlying causal processes in the contiguous U.S.
Authors: Schleeweis Karen , Goward Samuel N. , Huang Chengquan , Masek Jeffrey G. , Moisen Gretchen , Kennedy Robert E. , Thomas Nancy E.
Published: June 2013

The history of forest change processes is written into forest age and distribution and affects earth systems at many scales. No one data set has been able to capture the full forest disturbance and land use record through time, so in this study, we combined multiple lines of evidence to examine trends, for six US regions, in forest area affected by harvest, fire, wind, insects, and forest conversion to urban/surburban use. We built an integrated geodatabase for the contiguous U.S. (CONUS) with data spanning the nation and decades, from remote sensing observations of forest canopy dynamics, geospatial data sets on disturbance and conversion, and statistical inventories, to evaluate relationships between canopy change observations and casual processes at multiple scales. Results show the variability of major change processes through regions across decades. Harvest affected more forest area than any other major change processes in the North East, North Central, Southeast, and South central regions. In the Pacific Coast and Intermountain West, more forest area was affected by harvest than forest fires. Canopy change rates at regional scales confounded the trends of individual forest change processes, showing the importance of landscape scale data. Local spikes in observed canopy change rates were attributed to wind and fire events, as well as volatile harvest regimes. This study improves the geographic model of forest change processes by updating regional trends for major disturbance and conversion processes and combining data on the dynamics of fire, wind, insects, harvest, and conversion into one integrated geodatabase for the CONUS.
Differentiating the degradation dynamics of algal and terrestrial carbon within complex natural dissolved organic carbon in temperate lakes
Authors: Guillemette François , McCallister S. Leigh , del Giorgio Paul A.
Published: June 2013

It has often been hypothesized that the dissolved organic carbon (DOC) pool of algal origin in lakes is more bioavailable than its terrestrial counterpart, but this hypothesis has seldom been directly tested. Here we test this hypothesis by tracking the production and isotopic signature of bacterial respiratory CO2 in 2 week lake water incubations and use the resulting data to reconstruct and model the bacterial consumption dynamics of algal and terrestrial DOC. The proportion of algal DOC respired decreased systematically over time in all experiments, suggesting a rapid consumption and depletion of this substrate. Our results further show that the algal DOC pool was used in proportions and at rates twice and 10 times as high as the terrestrial DOC pool, respectively. On the other hand, the absolute amount of labile terrestrial DOC was on average four times higher than labile algal DOC, accounting for almost the entire long‐term residual C metabolism, but also contributing to short‐term bacterial C consumption. The absolute amount of labile algal DOC increased with chlorophyll a concentrations, whereas total phosphorus appeared to enhance the amount of terrestrial DOC that bacteria could consume, suggesting that the degradation of these pools is not solely governed by their respective chemical properties, but also by interactions with nutrients. Our study shows that there is a highly reactive pool of terrestrial DOC that is processed in parallel to algal DOC, and because of interactions with nutrients, terrestrial DOC likely supports high levels of bacterial metabolism and CO2 production even in more productive lakes.
On Switching to H‐Free Graphs
Authors: Jelínková Eva , Kratochvíl Jan
Published: June 2013

In this article, we study the problem of deciding if, for a fixed graph H, a given graph is switching equivalent to an H‐free graph. Polynomial‐time algorithms are known for H having at most three vertices or isomorphic to P4. We show that for H isomorphic to a claw, the problem is polynomial, too. On the other hand, we give infinitely many graphs H such that the problem is NP‐complete, thus solving an open problem [Kratochvíl, Nešetřil and Zýka, Ann Discrete Math 51 (1992)]. Further, we give a characterization of graphs switching equivalent to a K1, 2‐free graph by ten forbidden‐induced subgraphs, each having five vertices. We also give the forbidden‐induced subgraphs for graphs switching equivalent to a forest of bounded vertex degrees.