bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Erosion Impact on Soil Organic Carbon Spatial Variability on Steep Tropical Slopes
Authors: Chaplot Vincent , Podwojewski Pascal , Phachomphon Konngkeo , Valentin Christian
Published: March 2009

The main objectives of this study were to evaluate soil organic C (SOC) variability in a representative hillslope of Laos and to quantify the impact of some environmental factors. We collected 2348 soil samples from 581 georeferenced soil pits within a hillslope of northern Laos under traditional shifting cultivation at 0‐ to 0.05‐m depth and then every 0.1 m to 0.35‐m depth. The SOC stocks at 0‐ to 0.05‐m depth varied between 0.4 kg C m−2 (standard error of ±0.046 kg C m−2) and 1.9 (±0.22) kg C m−2 and stocks in the 0‐ to 0.35‐m depth were between 2.6 (±0.29) and 11.4 (±1.31) kg C m−2 About 85% of SOC spatial variability occurred at a distance less than 20 m. As expected, SOC content and stocks at 0‐ to 0.05‐m depth were significantly greater with higher soil clay content and shorter durations of cultivation (P < 0.001). But at 0‐ to 0.35‐m depth, the significance of clay content was only P = 0.04 and stocks surprisingly increased with increasing slope gradient (P < 0.001). Thus, it seems that sloping lands under shifting cultivation act as a conveyor that stores atmospheric inorganic C in soils during the regeneration of natural fallows and ultimately transfers it by water erosion to the steepest areas of hillslopes, where it accumulates, probably due to greater infiltration by water. These results on SOC spatial variations under steep slope conditions of the tropics give a better picture of SOC dynamics that may allow development of optimal strategies of land management to foster main soil functions and offset the current rise in atmospheric CO2
Efficiency Factors for Bark Substrates: Biostability, Aeration, or Phytotoxicity
Authors: Naasz R. , Caron J. , Legault J. , Pichette A.
Published: March 2009

In Quebec (Canada), approximately 3.5 million tons of bark are produced annually, most of which are burned or buried without being used or recycled, whereas they could be used as basic components in growing media. However, growing media made of fresh bark often inhibits plant growth due to high concentrations of phenols, terpenes, organic acids, and heavy metals or by creating physical barriers to gas exchange. Therefore, the objectives of this study were: first, to evaluate the phytotoxicity of barks from seven different tree species on lettuce (Lactuca sativa L. ‘Grand Rapids’) germination and tomato (Lycopersicon esculentum Mill. ‘Trust’) growth; and second, to identify the possible physical (aeration, water availability), chemical, or biochemical (heavy metal, phenol, terpene, and sugar concentrations) factors causing those reductions. Results show that bark origin affected both lettuce germination and tomato dry matter production. Best results were obtained with raw paper birch (Betula papyrifera Marsh.; PB) bark, which outperformed the control (rockwool). Among bark substrate properties, air‐filled porosity (θa) was significantly correlated to shoot dry weight (SDW) and germination index (GI). Plant growth parameters were correlated most strongly to biological stability, and then to θa, likely reflecting microbial competition for oxygen during the decomposition of organic matter. No relationships were found with terpenes, organic acids, or nutrient elements. These findings seemed to indicate that the apparent phytotoxicity of some barks could be explained by insufficient aeration in the substrate.
Activities of Nitrogen‐Mineralization Enzymes Associated with Soil Aggregate Size Fractions of Three Tillage Systems
Authors: Muruganandam Subathra , Israel Daniel W. , Robarge Wayne P.
Published: March 2009

Nitrogen mineralization occurring near the soil surface of agroecosystems determines the quantity of plant‐available N, and soil enzymes produced by microorganisms play significant roles in the N mineralization process. Tillage systems may influence soil microbial communities and N mineralization enzymes through alterations in total soil C and N. Soil aggregates of different sizes provide diverse microhabitats for microorganisms and therefore influence soil enzyme activities. Our objective was to test the hypothesis that activities of N mineralization enzymes increase with aggregate size and in no‐till compared with tilled systems. Potential activities ofN‐acetyl glucosaminidase (NAG), arylamidase,l‐glutaminase, andl‐asparaginase were measured in five aggregate size fractions (<0.25, 0.25–0.5, 0.5–1, 1–2, and 2–4 mm) obtained from soils of three long‐term (22‐yr) tillage systems (no‐till, chisel plow, and moldboard plow). All enzyme activities were significantly (P< 0.05) greater in no‐till than in tilled systems and positively correlated (P< 0.005) with potential N mineralization. Potential activities of NAG,l‐glutaminase, and arylamidase were significantly greater (P< 0.05) in the intermediate (0.5–1‐mm) aggregate size than in other size fractions. All enzyme activities were positively correlated with total soil C (P< 0.0001), N (P< 0.05), and microbial biomass C (P< 0.05). Aggregate size had significant effects on NAG, arylamidase, andl‐glutaminase activities but the magnitudes were small. Fungal biomarkers (18:2ω6c and 16:1ω5c) determined by the phospholipid fatty acid (PLFA) method were significantly greater in the no‐till than in tilled systems and positively correlated with all enzyme activities. This suggests that no‐till management enhances activities of N mineralization enzymes by enhancing the proportion of fungal organisms in the soil microbial community.
Sensitivity of Unlined Canal Seepage to Hydraulic Properties of Polyacrylamide‐Treated Soil
Authors: Zhu Jianting , Young Michael H.
Published: March 2009

High‐molecular‐weight, anionic, linear polyacrylamide (PAM) is being evaluated as a means of sealing unlined water delivery canals to reduce seepage losses. In this study, we investigated water seepage loss reduction by using a two‐layer one‐dimensional steady‐state conceptual model. The objectives of this study were twofold: (i) to examine the effectiveness and implications of a PAM‐treated thin layer at the bottom of the water delivery canal in reducing water seepage loss, and (ii) to investigate the sensitivity of seepage reduction to the hydraulic parameters of both the untreated and PAM‐treated thin layer. We incorporated laboratory‐measured saturated soil hydraulic conductivity results into the model to examine the seepage ratio of PAM‐treated vs. untreated soils and the sensitivity of the seepage ratio. In cases where PAM applications and suspended sediment concentration (SSC) treatment were effective, the uncertainty in the soil hydraulic parameter (sorptive number) α ratio of the PAM‐treated soil layer over the original soil had a significant impact on the uncertainty in the seepage ratio. For cases where the seepage ratio was insensitive to PAM and SSC treatment, the α ratio of the treated soil layer over the original soil layer was not significant. For a canal underlain by coarse‐textured material, uncertainty in the α ratio is propagated to the uncertainty in the seepage ratio and augmented more significantly, while for relatively fine‐textured sand (reflected in the small α values used in this study) the uncertainty propagation and augmentation are relatively gradual. For coarse‐textured sand, small uncertainty in the α ratio can lead to large uncertainty in the prediction of the seepage ratio.
A New Spectrophotometric Method for Rapid Semiquantitative Determination of Soil Organic Carbon
Authors: Harvey Omar R. , Herbert Bruce E. , Harris J. Pat , Stiffler Eric A. , Crenwelge Julie-Ann
Published: March 2009

Most methods to determine soil organic C (SOC) content are constrained by the time or equipment required, thereby limiting their use in determining the spatial variability of SOC across large areas. In this study, a new spectrophotometric method for the rapid determination of SOC was developed. The method is based on Beer's law,A= εlc, whereAis absorbance, ε is absorptivity,lis the path length, andcis the concentration of the absorbing species, and uses soil extract absorbance at 300 nm (A300nm) as a proxy for SOC. For organic C extractions, 1 mol L−1HCl followed by a 0.25 mol L−1NaOH−0.1 mol L−1Na4P2O7·10H2O solution was used (1:250 soil/extractant ratio). Evaluation of the method using 146 soil samples from 11 Major Land Resource Areas (MLRAs) across Texas indicated that SOC was linearly related toA300nmFor soils containing up to 50 g kg−1SOC, the relationship could be described by the equationA300nm= 5.0 SOC (r2= 0.89). The standard error and relative prediction deviation associated with the SOC values determined using the newly proposed method were 2.9 g kg−1SOC and 3.2, respectively. Calibration sample size, MLRA, soil texture, and inorganic C content had no significant effect on SOC extractability or method performance. In addition to being rapid, the method was accurate, stable, easy to execute, amendable to field use, and shows potential for use across large geographic areas comprised of soils from different parent materials and land uses.
Bioconversion of De-Oiled Rice Bran (DORB) Hemicellulosic Hydrolysate into Ethanol by Pichia stipitis NCM3499 under Optimized Conditions
Authors: Chandel Anuj Kumar , Narasu Mangamoori Lakshmi , Rudravaram Ravinder , Pogaku Ravindra , Rao Linga Venkateswar
Published: March 2009

In the present paper, parametric optimization studies were performed to determine the most influential range of process parameters for maximum ethanol production from Pichia stipitis NCIM3499 by one-at-a-time method under submerged fermentation conditions. Various parameters, such as agitation, pH of medium, temperature and different carbon sources, etc., were taken into consideration. The optimum values of these process parameters were as follows: agitation (200 rpm), pH (5.5), temperature (30°C), and semi-aerobic conditions (150 ml fermentation media in 250 ml Erlenmeyer flask). Among the different carbon substrates tested, glucose and xylose (20±0.21 g/l) showed same ethanol production (8.8±0.35 g/l) with a yield of 0.44±0.11g/g sugar utilized. These process parameters were applied for the ethanol production from de-oiled rice bran (DORB), the left over residue after extraction of oil. It was thermochemically saccharified using sulfuric acid (0.5-5.5% v/v) at 120°C for a fixed residence time of 1h. A maximum of 38.50±0.45 g/l total reducing sugars was obtained at 3.5% v/v H2SO4. This sugar syrup was detoxified by overliming with calcium hydroxide and subsequently fermented with P. stipitis NCIM3499 under the optimized conditions. After 72 h of incubation, DORB hydrolysate (33.50±0.44g/l total reducing sugars) showed maximum ethanol production (12.47±0.26g/l) with the yield 0.42±0.021g/g and fermentation efficiency of 81.74±0.55%. To the best of our knowledge, this is the first report on ethanol production from de-oiled rice bran using P. stipitis NCIM3499.
Optimization of a Convective Air Flow Solar Food Dryer
Authors: Russon Jonathan K , Dunn Michael L , Steele Frost M
Published: March 2009

A solar food dryer, previously developed for personal and small community use, was the object of this optimization study. Based on previous research of convective solar food dehydrators, several dryer parameters were identified for this study. Chimney height and dryer product load were two factors tested in a central composite experimental design. Dryer product load was found to produce a maximum efficiency of the dryer when fifteen product-filled trays were inserted in the dryer. Maximum efficiency was observed at the maximum chimney height tested. Post-optimization configuration compared with pre-optimization configuration resulted in a 40% increase in final dry product production per hour of dehydration time.
Extrusion Processing of Starch Film
Authors: Su Bing , Xie Fengwei , Li Ming , Corrigan Penny A , Yu Long , Li Xiaoxi , Chen Ling
Published: March 2009

Processing behaviors of starch film using a twin screw extruder were studied; in particular the effect of processing conditions, such as temperature, screw speed, feeding speed, and water content, on the extrusion torque and die pressure were systematically investigated. A specific focus of this work was to investigate the effect of amylose/amylopectin ratio containing in cornstarch on the film processing and performances. It was found that the processibility was decreased as the amylose content increased. Pre-mixing and equilibration improve the processibility of starch films, especially for the high amylose starches. The high amylose starches need higher moisture content and temperature for film extrusion.
New form of the Euler-Bernoulli rod equation applied to robotic systems
Authors: Filipovic Mirjana
Published: March 2009

This paper presents a theoretical background and an example of extending the Euler-Bernoulli equation from several aspects. Euler-Bernoulli equation (based on the known laws of dynamics) should be supplemented with all the forces that are participating in the formation of the bending moment of the considered mode. The stiffness matrix is a full matrix. Damping is an omnipresent elasticity characteristic of real systems, so that it is naturally included in the Euler-Bernoulli equation. It is shown that Daniel Bernoulli's particular integral is just one component of the total elastic deformation of the tip of any mode to which we have to add a component of the elastic deformation of a stationary regime in accordance with the complexity requirements of motion of an elastic robot system. The elastic line equation mode of link of a complex elastic robot system is defined based on the so-called 'Euler-Bernoulli Approach' (EBA). It is shown that the equation of equilibrium of all forces present at mode tip point ('Lumped-mass approach' (LMA)) follows directly from the elastic line equation for specified boundary conditions. This, in turn, proves the essential relationship between LMA and EBA approaches. In the defined mathematical model of a robotic system with multiple DOF (degree of freedom) in the presence of the second mode, the phenomenon of elasticity of both links and joints are considered simultaneously with the presence of the environment dynamics - all based on the previously presented theoretical premises. Simulation results are presented. .
Efficacy and Safety of the Human Glucagon-Like Peptide-1 Analog Liraglutide in Combination With Metformin and Thiazolidinedione in Patients With Type 2 Diabetes (LEAD-4 Met+TZD)
Authors: Zinman Bernard , Gerich John , Buse John B. , Lewin Andrew , Schwartz Sherwyn , Raskin Philip , Hale Paula M. , Zdravkovic Milan , Blonde Lawrence ,   the LEAD-4 Study Investigators
Published: March 2009

OBJECTIVE

To determine the efficacy and safety of liraglutide (a glucagon-like peptide-1 receptor agonist) when added to metformin and rosiglitazone in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This 26-week, double-blind, placebo-controlled, parallel-group trial randomized 533 subjects (1:1:1) to once-daily liraglutide (1.2 or 1.8 mg) or liraglutide placebo in combination with metformin (1 g twice daily) and rosiglitazone (4 mg twice daily). Subjects had type 2 diabetes, A1C 7–11% (previous oral antidiabetes drug [OAD] monotherapy ≥3 months) or 7–10% (previous OAD combination therapy ≥3 months), and BMI ≤45 kg/m2.

RESULTS

Mean A1C values decreased significantly more in the liraglutide groups versus placebo (mean ± SE −1.5 ± 0.1% for both 1.2 and 1.8 mg liraglutide and −0.5 ± 0.1% for placebo). Fasting plasma glucose decreased by 40, 44, and 8 mg/dl for 1.2 and 1.8 mg and placebo, respectively, and 90-min postprandial glucose decreased by 47, 49, and 14 mg/dl, respectively (P < 0.001 for all liraglutide groups vs. placebo). Dose-dependent weight loss occurred with 1.2 and 1.8 mg liraglutide (1.0 ± 0.3 and 2.0 ± 0.3 kg, respectively) (P < 0.0001) compared with weight gain with placebo (0.6 ± 0.3 kg). Systolic blood pressure decreased by 6.7, 5.6, and 1.1 mmHg with 1.2 and 1.8 mg liraglutide and placebo, respectively. Significant increases in C-peptide and homeostasis model assessment of β-cell function and significant decreases in the proinsulin-to-insulin ratio occurred with liraglutide versus placebo. Minor hypoglycemia occurred more frequently with liraglutide, but there was no major hypoglycemia. Gastrointestinal adverse events were more common with liraglutide, but most occurred early and were transient.

CONCLUSIONS

Liraglutide combined with metformin and a thiazolidinedione is a well-tolerated combination therapy for type 2 diabetes, providing significant improvements in glycemic control.
Pop Life: An Introduction
Authors: Rak Julie
Published: March 2009

This collection of essays deals with an important form of representation in American culture today: popular auto/biography. Popular auto/biographical discourse appears in a dizzying array of forms in North America, including personal documentaries, graphic books, song lyrics, personal zines, and celebrity memoirs. It is worth considering that, during a time when it is becoming hard for the general public to trust political and spiritual leaders, auto/biographical representations by celebrities and by “ordinary” Americans are on the rise: there are thousands of memoirs and biographies in print, and memoirs like Tuesdays with Morrie stay at the top of bestseller lists for years at a time. The scholars in this special issue examine a mix of popular and everyday auto/biographical practices and texts—from Eminem to the commemorative monuments of violent acts against women—in order to consider what life narratives mean in a public sphere where, more than ever, the personal is political.
Drawn from Memory: Comics Artists and Intergenerational Auto/biography
Authors: Rifkind Candida
Published: March 2009

This article examines the dynamics of father–son relationships and the problems of intergenerational collaboration in Art Spiegelman's Maus I and II, Seth and John Gallant's Bannock, Beans, and Black Tea: Memories of a Prince Edward Island Childhood during the Depression, and Chris Ware's Jimmy Corrigan: The Smartest Kid on Earth. All three authors are critically acclaimed cartoonists and graphic novelists who use the mixed medium of verbal–visual narratives to tell stories about biological and symbolic fathers. These works reject dominant notions of masculinity and fatherhood through various forms of collaborative auto/biography and intergenerational semi-auto/biography that gravitate towards an aesthetics of smallness. The article concludes that, even as these three projects stage a reconciliation between fathers and sons, past and present, public and private, they nevertheless question the politics and practices of representing self and other in popular graphic form.
Load of Aeromonas salmonicida in Swamp Water and it's Effect on Tilapia (Oreochromis mossambicus)
Authors: Khatun Habiba , Afza Rowshatul , Hossain M Iqbal , Hussain M Afzal , Khan AR , Rahman M Habibur , Neela Farzana Ashrafi
Published: March 2009

Swamps are one of those types of lentic water bodies, which form links between terrestrial and aquatic ecosystems. Dehadrai and Tripathi (1976) have characterized these water bodies as waterlogged, shallow water areas with a loose peaty bottom, rich in decaying organic matter retaining water either periodically or shrinking or drying summer months. There are numerous water bodies, including swamps, present in Bangladesh. But all of these water bodies are not used for scientific fish culture. To meet the increasing protein demand and to solve the unemployment problem in Bangladesh, swamps should be used for fish culture scientifically. This may also be helpful to destroy the habitat of many biological vectors such as mosquitoes. doi: 10.3329/jbs.v15i0.2158 J. bio-sci. 15: 165-168, 2007
Le ministère français de la guerre face à l'invention des frères Wright (1905-1906)
Authors: Carlier Claude
Published: March 2009

Le ministère français de la guerre face à l’invention des frères Wright (1905-1906) Il y a désormais plus d’un siècle que les États-Unis et la France se sont lancés dans la conquête des cieux par un appareil plus lourd que l’air motorisé, un des plus importants événements de l’histoire de l’humanité. Les applications militaires ont immédiatement été perçues par le ministère français de la Guerre qui a envisagé l’achat de la machine volante de deux Américains, les frères Wilbur et Orville Wright. Une mission secrète d’achat a été envoyée aux États-Unis. Les négociations n’ont pas abouti pas, mais ont été à l’origine des premiers et spectaculaires vols de Wilbur Wright en France en 1908.
One‐Pot Multienzymatic Synthesis of 12‐Ketoursodeoxycholic Acid: Subtle Cofactor Specificities Rule the Reaction Equilibria of Five Biocatalysts Working in a Row
Authors: Monti Daniela , Ferrandi Erica Elisa , Zanellato Ilaria , Hua Ling , Polentini Fausto , Carrea Giacomo , Riva Sergio
Published: March 2009

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The hydroxysteroid dehydrogenases (HSDHs)‐catalyzed one‐pot enzymatic synthesis of 12‐ketoursodeoxycholic acid (3α,7β‐dihydroxy‐12‐oxo‐5β‐cholanoic acid), a key intermediate for the synthesis of ursodeoxycholic acid, from cholic acid has been investigated. This goal has been achieved by alternating oxidative and reductive steps in a one‐pot system employing HSDHs with different cofactor specificity, namely NADH‐dependent HSDHs in the oxidative step and an NADPH‐dependent 7β‐HSDH in the reductive one. Coupled in situ regeneration systems have been exploited not only to allow the use of catalytic amounts of the cofactors, but also to provide the necessary driving force to opposite reactions (i.e., oxidation and reduction) acting on different sites of the substrate molecule. Biocatalysts suitable for the set‐up of this process have been selected and their kinetic behaviour in respect of the reactions of interest has been evaluated. Finally, the process has been studied employing the enzymes both in free and compartmentalized form.
Interspecies comparisons of functional genetic variations and their implications in neuropsychiatry
Authors: Kas Martien J.H. , Gelegen Cigdem , Schalkwyk Leonard C. , Collier David A.
Published: March 2009

Animal studies are important for the identification and functional characterization of the biological substrates underlying complex psychiatric disorders. However, novel insights into the relationship between the genome and behavior are needed for the development of fully valid translational models. Based on the notion that in different species, the same genes may independently give rise to alleles with similar functional and phenotypic effects, either under similar selection or through similar genomic mechanisms, we propose the use of genetic validity as a tool for identifying analogous pathology between animals and human neuropsychiatric disorders. Furthermore, the identification of copy number variants which disrupt entire genes, reinforces the notion that transgenic animals, such as knockouts or knock‐ins, may provide unexpectedly valid disease models for psychiatric traits. To illustrate interspecies comparison of genetic variations in relation to neurobehavioral traits, examples are provided for the BDNF, COMT, and DISC1 genes in mouse and man. We propose that alignment of individual genetic variations with endophenotypes obtained from mice and across categories of neuropsychiatric disorders will provide an important step in translational research. © 2008 Wiley‐Liss, Inc.
Broken ribs: Paleopathological analysis of costal fractures in the human identified skeletal collection from the Museu Bocage, Lisbon, Portugal (late 19th to middle 20th centuries)
Authors: Matos Vítor
Published: March 2009

Although rarely reported in the anthropological literature, rib fractures are commonly found during the analysis of human skeletal remains of past and modern populations. This lack of published data precludes comparison between studies and restricts an accurate understanding either of the mechanisms involved in thoracic injuries or their impact on past societies. The present study aimed: 1) to report rib fracture prevalence in 197 individuals, 109 males, and 88 females, with ages at death ranging from 13 to 88 years old, from the Human Identified Skeletal Collection, Museu Bocage, Portugal (late 19th‐middle 20th centuries); 2) to test the hypothesis that a higher prevalence of rib stress fractures existed in the 133 individuals who died from respiratory diseases, in a period before antibiotics. The macroscopic analysis revealed 23.9% (n = 47) of individuals with broken ribs. 2.6% (n = 124) out of 4,726 ribs observed were affected. Males presented more rib fractures, and a significantly higher prevalence was noted for older individuals. Fractures were more frequently unilateral (n = 34), left sided (n = 19) and mainly located on the shaft of ribs from the middle thoracic wall. Nineteen individuals presented adjacent fractured ribs. Individuals who died from pulmonary diseases were not preferentially affected. However, a higher mean rate of fractures was found in those who died from pneumonia, a scenario still common nowadays. Since rib involvement in chest wall injury and its related outcomes are important issues both for paleopathology and forensic anthropology, further investigations are warranted. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
The type specimen (LB1) ofHomo floresiensisdid not have Laron Syndrome
Authors: Falk Dean , Hildebolt Charles , Smith Kirk , Jungers William , Larson Susan , Morwood Michael , Sutikna Thomas , Jatmiko  , Saptomo E. Wahyu , Prior Fred
Published: March 2009

The type specimen (LB1) ofHomo floresiensishas been hypothesized to be a pathological human afflicted with Laron Syndrome (LS), a type of primary growth hormone insensitivity (Hershkovitz et al.: Am J Phys Anthropol 134 [2007] 198–208). Comparing measurements, photographs and three‐dimensional, computed‐tomography reconstructions of LB1 with data and diagnoses from the literature on LS, we critically evaluate numerous skull and postcranial traits that Hershkovitz etal. identified as being shared by LB1 and patients with LS. The statements regarding most of these traits are new to the clinical literature and lack quantitative support. LB1 and patients with LS differ markedly in the size and shape of the cranium; thickness and pneumatization of cranial bones; morphology of the face, mandible, teeth, and chin; form of the shoulder, wrist, and pelvis; and general body proportions including relative foot size. Claims that patients with LS are similar to LB1 in displaying protracted scapulae, short clavicles, low degrees of humeral torsion, flaring ilia, and curved tibiae are not supported by data or corroborating images. Some points of similarity (e.g., femoral neck‐shaft angle, femoral bicondylar angle, and estimated stature) can be found in other hominins, and cannot be considered diagnostic. From our review and analysis, we conclude that LB1 did not suffer from LS. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.
Redoxökonomie in der organischen Synthese
Authors: Burns Noah Z. , Baran Phil S. , Hoffmann Reinhard W.
Published: March 2009

Anregungen für die organische Synthese: Stufen‐ und Atomökonomie haben sich als nützliche Kriterien erwiesen, an denen sich die Effizienz einer Synthese festmachen lässt. Dieser Aufsatz weist auf eine weitere Form der Ökonomie hin, die bei der Planung und Bewertung einer mehrstufigen Synthese berücksichtigt werden sollte: die Redoxökonomie. Etliche Beispiele und Leitfäden werden vorgestellt, die das Konzept illustrieren und Anregungen für die Syntheseplanung geben.

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“Ökonomie” bezeichnet den sparsamen und effizienten Umgang mit materiellen Ressourcen, das Prinzip, sein Ziel mit einem minimalen Aufwand zu erreichen. Vielleicht noch treffender: “Seine Kräfte so einzuteilen, um möglichst wenig davon zur Erreichung eines Ziels zu verbrauchen”. Diese Aussagen treffen sicher auch zu, wenn es darum geht, ein komplexes Zielmolekül zu synthetisieren. Redoxökonomie bedeutet dann, so wenig wie möglich Redoxschritte in der Synthese eines Zielmoleküls einzusetzen. Während jede Art von Ökonomie hilft, den Aufwand einer Totalsynthese in Grenzen zu halten, betrifft Redoxökonomie einen besonderen Schwachpunkt heutiger Totalsynthesen. Es genügt nicht, auf dieses Defizit zu verweisen, vielmehr soll dieser Aufsatz allen mit Totalsynthese Befassten einen Leitfaden geben und Hinweise beisteuern, wie sich die Redoxökonomie in mehrstufigen Synthesefolgen der organischen Chemie verbessern lässt.
Iron‐Catalyzed Chemoselective ortho Arylation of Aryl Imines by Directed CH Bond Activation
Authors: Yoshikai Naohiko , Matsumoto Arimasa , Norinder Jakob , Nakamura Eiichi
Published: March 2009

Naheliegende Alternative: Eine eisenkatalysierte Imin‐gesteuerte C‐H‐Aktivierung mit einem Diarylzinkreagens führt eine Arylgruppe in ortho‐Stellung an einem von Acetophenon abgeleiteten Imin ein (siehe Schema); mit einem Palladiumkatalysator tritt dagegen eine gewöhnliche Substitution auf. Die Titelreaktion ist eine milde C‐H‐Aktivierung, die in Gegenwart von 1,2‐Dichlorisobutan mit Arylbromiden, ‐chloriden oder ‐sulfonaten selektiv verläuft.

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Innentitelbild: A Nanoscale Molecular Switch Triggered by Thermal, Light, and Guest Perturbation (Angew. Chem. 14/2009)
Authors: Duriska Martin B. , Neville Suzanne M. , Moubaraki Boujemaa , Cashion John D. , Halder Gregory J. , Chapman Karena W. , Balde Chérif , Létard Jean‐François , Murray Keith S. , Kepert Cameron J. , Batten Stuart R.
Published: March 2009

Ein kontinuierlicher Wechsel zwischen magnetischen High‐Spin‐ und Low‐Spin‐Zuständen wird durch Einstrahlen von rotem bzw. grünem Laserlicht erreicht. In der Zuschrift auf S. 2587 ff. berichten S. R. Batten et al. über ein Metallosupramolekül, bei dem durch Temperaturwechsel oder durch Einstrahlen von Licht ein Spin‐Crossover(SCO)‐Schalten möglich ist. Das SCO‐Verhalten hängt zudem von der Gegenwart und der Art eingeschlossener Lösungsmittelmoleküle in der porösen Kristallstruktur ab.

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Chemical and Structural Diversity in Eumelanins: Unexplored Bio‐Optoelectronic Materials
Authors: d'Ischia Marco , Napolitano Alessandra , Pezzella Alessandro , Meredith Paul , Sarna Tadeusz
Published: March 2009

A black whole: The black insoluble biopolymer eumelanin is prepared through the oxidative polymerization of 5,6‐dihydroxyindoles (see scheme). It has a largely unknown heterogeneous structure and unique optoelectronic properties. Current structural models are presented and possible applications are discussed.

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Eumelanins, the characteristic black, insoluble, and heterogeneous biopolymers of human skin, hair, and eyes, have intrigued and challenged generations of chemists, physicists, and biologists because of their unique structural and optoelectronic properties. Recently, the methods of organic chemistry have been combined with advanced spectroscopic and imaging techniques, theoretical calculations, and methods of condensed‐matter physics to gradually force these materials to reveal their secrets. Herein we review the latest advances in the field with a view to showing how the emerging knowledge is not only helping to explain eumelanin functionality, but may also be translated into effective strategies for exploiting their properties to create a new class of biologically inspired high‐tech materials.
Targeting Bone Metastases with a Bispecific Anticancer and Antiangiogenic Polymer–Alendronate–Taxane Conjugate
Authors: Miller Keren , Erez Rotem , Segal Ehud , Shabat Doron , Satchi‐Fainaro Ronit
Published: March 2009

A polymer therapeutic designed for combination anticancer and antiangiogenic therapy inhibited the proliferation of prostate carcinoma cells and the proliferation, migration, and tube‐formation of endothelial cells. The nanoconjugate was formed from an N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer, the bisphosphonate alendronate (for bone targeting), and the chemotherapy agent paclitaxel (PTX), which is cleaved by cathepsin B (see scheme).

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Enhanced Hydrogen Storage by Palladium Nanoparticles Fabricated in a Redox‐Active Metal–Organic Framework
Authors: Cheon Young Eun , Suh Myunghyun Paik
Published: March 2009

Quick on the uptake: Palladium nanoparticles were fabricated simply by immersing {[Zn3(ntb)2(EtOH)2]⋅4 EtOH}n (1) in an MeCN solution of Pd(NO3)2 at room temperature, without any extra reducing agent. 3 wt % PdNPs@[1]0.54+(NO3−)0.54 significantly increase H2 uptake capacities, both at 77 K and 1 bar and at 298 K and high pressures (see picture, red curve) compared to [Zn3(ntb)2]n (black). ntb=4,4′,4′′‐nitrilotrisbenzoate.

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Total Synthesis of Ciguatoxin
Authors: Hamajima Akinari , Isobe Minoru
Published: March 2009

Something fishy: Ciguatoxin (see structure) is one of the principal toxins involved in ciguatera poisoning and the target of a total synthesis involving the coupling of three segments. The key transformations in this synthesis feature acetylene–dicobalthexacarbonyl complexation.

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Redox Economy in Organic Synthesis
Authors: Burns Noah Z. , Baran Phil S. , Hoffmann Reinhard W.
Published: March 2009

Stimulus package for organic synthesis: The economy of step and atom usage has been widely reviewed and acknowledged as being useful frameworks to evaluate the efficiency of synthesis. This Review brings to attention another form of economy which should be considered in the planning and evaluation of a multistep synthesis: redox economy. Several guidelines and examples are included to illustrate the logic of this approach and to stimulate the design of syntheses.

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“Economy” is referred to as the thrifty and efficient use of material resources, as the principle of “minimum effort to reach a goal.” More illuminating is: “the aim to portion one's forces in order to use as little as possible of them to reach a goal.” Such statements certainly apply when the goal is to synthesize a complex target molecule. Redox economy then implies the use of as few redox steps as possible in the synthetic conquest of a target compound. While any sort of economy will help to streamline the effort of total synthesis, redox economy addresses a particularly weak area in present‐day total synthesis. It is not enough to point out the present deficiencies, rather the purpose of this Review is to serve as a teaching tool for all practitioners of the field by giving and illustrating guidelines to increase redox economy in multistep organic synthesis.
Evidence for CCl/CBr⋅⋅⋅π Interactions as an Important Contribution to Protein–Ligand Binding Affinity
Authors: Matter Hans , Nazaré Marc , Güssregen Stefan , Will David W. , Schreuder Herman , Bauer Armin , Urmann Matthias , Ritter Kurt , Wagner Michael , Wehner Volkmar
Published: March 2009

Attractive chlorine: Noncovalent interactions between chlorine or bromine atoms and aromatic rings in proteins open up a new method for the manipulation of molecular recognition. Substitution at distinct positions of two factor Xa inhibitors improves the free energy of binding by interaction with a tyrosine unit. The generality of this motif was underscored by multiple crystal structures as well as high‐level quantum chemical calculations (see picture).

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A Supramolecular Polymer as a Self‐Assembling Polyvalent Scaffold
Authors: Müller Marion K. , Brunsveld Luc
Published: March 2009

Binding bacteria: Discotic molecules self‐assemble into columnar supramolecular polymers that show strong polyvalent binding to bacteria by virtue of mannose ligands attached at their periphery (orange; see picture). The reversible formation of the supramolecular polymers allows simple mixing of differently substituted monomers and the optimization of bacterial aggregation.

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Total Synthesis of Ouabagenin and Ouabain
Authors: Reddy Maddi Sridhar , Zhang Hongxing , Phoenix Serge , Deslongchamps Pierre
Published: March 2009

All done! A full account of the total synthesis of ouabagenin and ouabain has been described. The synthesis was achieved through a polyanionic cyclization strategy. Degradation studies provide an ultimate proof for a key intermediate observed in the synthesis.

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A full account of the total synthesis of ouabagenin and ouabain is described. A highly stereocontrolled anionic cycloaddition for the rapid construction of the basic steroid skeleton is a pivotal conversion for the whole strategy. A careful study was needed to establish the order and the sequence of functional group manipulations. Specific conformational features of the ouabain skeleton allowed us to overcome a few stereochemical problems. Degradation studies on ouabain provided an ultimate proof for a key intermediate, which is used as a relay. Late stage butenolide formation and glycosidation yielded ouabain.
Influence of Tl+ activator ions on the luminescence characteristics of KCl0.5Br0.5:Eu2+ powder phosphors
Authors: Nagarajan S. , Sudarkodi R.
Published: March 2009

Photoluminescence (PL) of thallium co‐doped with KCl0.5Br0.5:Eu2+ powder phosphors display emission bands at 320 and 370 nm attributable to centres involving Tl+ ions in addition to characteristic Eu2+ emission around 420 nm. Additional PL excitation and emission bandS observed around 260 and 380 nm, respectively, were observed in the double‐doped KCl0.5Br0.5:Eu2+, Tl+ powder phosphors and are attributed to complex centres involving Tl+ and Eu2+ ions. The enhancement observed in the intensity of Eu2+ emission around 420 nm with the addition of TlBr in KCl0.5Br0.5:Eu2+ powder phosphors is attributed to the energy transfer from Tl+ → Eu2+ ions. Photostimulated luminescence (PSL) studies of γ‐irradiated KCl0.5Br0.5:Eu2+, Tl+ mixed phosphors are reported and a tentative PSL mechanism in the phosphors has been suggested. Copyright © 2009 John Wiley & Sons, Ltd.
Analytical quantification of low‐density lipoprotein using europium tetracycline indicator
Authors: De Oliveira Silva Flávia Rodrigues , Monteiro Andrea Moreira , Neto Antônio M. Figueiredo , Gidlund Magnus , Junior Nilson Dias Vieira , Courrol Lilia Coronato
Published: March 2009

Low‐density lipoprotein (LDL) is known as ‘bad’ cholesterol. If too much LDL circulates in the blood it can be retained in the walls of the arteries, causing atherosclerosis. In this paper we showed an alternative method to quantify LDL using the europium tetracycline (EuTc) indicator. The optical properties of the EuTc complex were investigated in aqueous solutions containing LDL. An enhancement was observed of the europium luminescence in the solutions with LDL compared those without the lipoprotein. A method to quantify the amount of LDL in a sample, based on EuTc enhanced luminescence, is proposed. The enhancement mechanism is also discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Relationship between ultra‐weak bioluminescence and vigour or irradiation dose of irradiated wheat
Authors: Wang Jun , Yu Yong
Published: March 2009

Ultra‐weak luminescent analysis is a new way to detect the irradiation dose and the vigour of irradiated wheat. Wheat grain and wheat flour were used in this research for ultra‐weak luminescent analysis. The experimental data showed that the bioluminescence intensity of wheat grain sample was different with increasing storage time and increasing dose, and a similar trend appeared in the germination rates of irradiated wheat grain. It was found that the differences in bioluminescence intensities and germination rates of irradiated wheat grain at different doses and storage times were due to the effect of irraditation on the wheat embryo and self‐repair during storage. As a result, ultra‐weak luminescent analysis cannot be used to detect the irradiation dose of irradiated wheat, but it can be used to determine vigour. Experiments showed that the irradiation dose had a highly significant effect on the bioluminescence intensities of wheat flour when cane sugar was added. Copyright © 2009 John Wiley & Sons, Ltd.
A novel chemiluminescent flow injection analysis of trace amounts of rutin by its inhibition of the luminol–hydrogen peroxide reaction catalyzed by tetrasulfonated colbalt phthalocyanine
Authors: Zhu Qiyong
Published: March 2009

Based on the inhibition effect of rutin on the luminol–hydrogen peroxide chemiluminescence (CL) system catalyzed by tetrasulfonated colbalt phthalocyanine (CoTSPc), a sensitive flow‐injection CL method has been developed for the determination of rutin. The CL reaction mechanism was carefully investigated by examining CL emission spectra, UV–visible spectra and variation of reaction conditions. It was found that there existed a linear relationship between CL intensity and the concentration of rutin in the range of 8.0 × 10−9 to 1.0 × 10−6 mol L−1, and the detection limit is 3.8 × 10−9 mol L−1. This proposed method is sensitive, convenient and simple, and has been applied to the determination of rutin in commercial rutin tablets with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.
Fluorescence sensing of nitric oxide in aqueous solution by triethanolamine‐modified CdSe quantum dots
Authors: Yan Xiao Qing , Shang Zhuo Bin , Zhang Zhao , Wang Yu , Jin Wei Jun
Published: March 2009

The water‐soluble luminescent CdSe quantum dots were prepared by ligand exchange with triethanolamine (TEA). Oxygen can reversibly enhance the fluorescence of the synthesized quantum dots (TEA‐CdSe‐QDs) in aqueous solution. Nitric oxide radical (NO) can react easily with dissolved oxygen in water and was found to have a significant quenching effect on the fluorescence of the TEA‐CdSe‐QDs. The fluorescence responses were concentration‐dependent and can be well described by the typical Stern–Volmer equation. A good linear relationship (R2 = 0.9963) was observed over the range 5.92 × 10−7 to 1.85 × 10−5 mol/L nitric oxide. Above this concentration was a second linear region ranging from 2.12 × 10−5 to 1.12 × 10−4 mol/L NO with a gentler slope. The detection limit, calculated following the 3σ IUPAC criteria, was 3.02 × 10−7 mol/L. The interference effect of some common interferents such as nitrite (NO2−), nitrate (NO3−), glucose and l‐ascorbic acid on the detection of NO was negligible for the proposed system, demonstrating the potential utility of this probe for the detection of NO in biological systems. The possible mechanism was also discussed. Copyright © 2009 John Wiley & Sons, Ltd.
The effect of continuous culture on the growth and structure of tissue‐engineered cartilage
Authors: Khan Aasma A. , Suits Jocelyne M. T. , Kandel Rita A. , Waldman Stephen D.
Published: March 2009

The use of bioreactors for cartilage tissue engineering has become increasingly important as traditional batch‐fed culture is not optimal for in vitro tissue growth. Most tissue engineering bioreactors rely on convection as the primary means to provide mass transfer; however, convective transport can also impart potentially unwanted and/or uncontrollable mechanical stimuli to the cells resident in the construct. The reliance on diffusive transport may not necessarily be ineffectual as previous studies have observed improved cartilaginous tissue growth when the constructs were cultured in elevated volumes of media. In this study, to approximate an infinite reservoir of media, we investigated the effect of continuous culture on cartilaginous tissue growth in vitro. Isolated bovine articular chondrocytes were seeded in high density, 3D culture on Millicell™ filters. After two weeks of preculture, the constructs were cultivated with or without continuous media flow (5–10 μL/min) for a period of one week. Tissue engineered cartilage constructs grown under continuous media flow significantly accumulated more collagen and proteoglycans (increased by 50–70%). These changes were similar in magnitude to the reported effect of through‐thickness perfusion without the need for large volumetric flow rates (5–10μL/min as opposed to 240–800 μL/min). Additionally, tissues grown in the reactor displayed some evidence of the stratified morphology of native cartilage as well as containing stores of intracellular glycogen. Future studies will investigate the effect of long‐term continuous culture in terms of extracellular matrix accumulation and subsequent changes in mechanical function. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Expression of functional Candida antarctica lipase B in a cell‐free protein synthesis system derived from Escherichia coli
Authors: Park Chang‐Gil , Kim Tae‐Wan , Oh In‐Seok , Song Jae Kwang , Kim Dong‐Myung
Published: March 2009

This article reports the cell‐free expression of functional Lipase B from Candida antarctica (CalB) in an Escherichia coli extract. Although most of the cell‐free synthesized CalB was insoluble under conventional reaction conditions, the combined use of molecular chaperones led to the soluble expression of CalB. In addition, the functional enzyme was generated by applying the optimal redox potential. When examined using p‐nitrophenyl palmitate as a substrate, the specific activity of the cell‐free synthesized CalB was higher than that of the reference protein produced in Pichia pastoris. These results highlight the potential of cell‐free protein synthesis technology as a powerful platform for the rapid expression, screening and analysis of industrially important enzymes. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Enzymatic digestion of liquid hot water pretreated hybrid poplar
Authors: Kim Youngmi , Mosier Nathan S. , Ladisch Michael R.
Published: March 2009

Liquid hot (LHW) water pretreatment (LHW) of lignocellulosic material enhances enzymatic conversion of cellulose to glucose by solubilizing hemicellulose fraction of the biomass, while leaving the cellulose more reactive and accessible to cellulase enzymes. Within the range of pretreatment conditions tested in this study, the optimized LHW pretreatment conditions for a 15% (wt/vol) slurry of hybrid poplar were found to be 200oC, 10 min, which resulted in the highest fermentable sugar yield with minimal formation of sugar decomposition products during the pretreatment. The LHW pretreatment solubilized 62% of hemicellulose as soluble oligomers. Hot‐washing of the pretreated poplar slurry increased the efficiency of hydrolysis by doubling the yield of glucose for a given enzyme dose. The 15% (wt/vol) slurry of hybrid poplar, pretreated at the optimal conditions and hot‐washed, resulted in 54% glucose yield by 15 FPU cellulase per gram glucan after 120 h. The hydrolysate contained 56 g/L glucose and 12 g/L xylose. The effect of cellulase loading on the enzymatic digestibility of the pretreated poplar is also reported. Total monomeric sugar yield (glucose and xylose) reached 67% after 72 h of hydrolysis when 40 FPU cellulase per gram glucan were used. An overall mass balance of the poplar‐to‐ethanol process was established based on the experimentally determined composition and hydrolysis efficiencies of the liquid hot water pretreated poplar. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009