bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of phenylpropanoids in green and red pepper fruits of semi-hot cultivars Capsicum annuum L.
Authors: Materska Małgorzata , Perucka Irena
Published: April 2013

The aim of the present work was to determine differences in C and O glycosides of flavonoids, derivatives of phenolic acids, as well as capsaicinoid content in two semi-hot pepper cultivars, cv. Tornado and Tajfun. Fruits were harvested at the green and red maturity stages. Flavonoid and capsaicinoid fractions were isolated on Sep-Pak C18 cartridges with 40% and 70% methanol-water solutions, respectively. The chemical composition of both fractions was determined by HPLC method using standards of phenolic compounds obtained in the earlier work and the capsaicin standard. The flavonoid fraction contained glucose esters of phenolic acid, mainly ferulic and sinapic acid, as well as derivatives of flavonoids, quercetin, luteolin and apigenin, which occurred as O- and C- glycosides with glucose, rhamnose, and apiose. The capsaicinoid fraction contained mainly capsaicin and dihydrocapsaicin. It was found that in green fruits flavonoid O-glycosides were the predominant phenolics, while in red ones derivatives of phenolic acids. A higher loss of O-glycosides of flavonoids than of C-glycosides was observed during the maturation of the fruit of semi-hot pepper cultivars.
Effect of gibberellic acid spraying and soaking of rhizomes on the growth and flowering of calla lily (Zantedeschia Spreng.)
Authors: Janowska Beata , Andrzejak Roman
Published: April 2013

Rhizomes of Zantedeschia, 15-18 cm in circumference with leaf buds 0.5-1 cm in length, were planted into 20-cm pots on 15 May 2006 into a medium consisting of peat with a pH of 6.2, enriched with a slow-release fertiliser Osmocote Plus (3-4M) and mixed with fresh shredded pine bark at a rate of 3:1 (v:v). Before planting, the rhizomes were soaked for 20 minutes in a water solution of gibberellic acid at a concentration of 150 mg x dm-3, or sprayed with the same concentration once, twice or three times, each time after thorough drying. For each round of spraying, 100 ml of the solution were used. Gibrescol 10 MG was applied. Gibberellic acid had a similar effect, whether applied in the form of a solution for soaking or spraying of rhizomes. The number of sprayings of rhizomes had no effect on the effectiveness of gibberellic acid. In the cultivar 'Black Magic', rhizome spraying caused earlier flowering, while in 'Cameo' a similar effect was obtained by soaking the rhizomes in gibberellic acid. Gibberellic acid had no effect on the quality of flowers and the number of leaves. Gibberellic acid had a good effect on the index of leaf greenness in the cultivars under study.
Stem Cell Therapy to Cure Type 1 Diabetes: From Hype to Hope
Authors: Chhabra Preeti , Brayman Kenneth L.
Published: April 2013

Type 1 diabetes mellitus (T1D) is a chronic, multifactorial autoimmune disease that involves the progressive destruction of pancreatic β-cells, ultimately resulting in the loss of insulin production and secretion. The goal of clinical intervention is to prevent or arrest the onset and progression of autoimmunity, reverse β-cell destruction, and restore glycometabolic and immune homeostasis. Despite promising outcomes observed with islet transplantation and advancements in immunomodulatory therapies, the need for an effective cell replacement strategy for curing T1D still persists. Stem cell therapy offers a solution to the cited challenges of islet transplantation. While the regenerative potential of stem cells can be harnessed to make available a self-replenishing supply of glucose-responsive insulin-producing cells, their immunomodulatory properties may potentially be used to prevent, arrest, or reverse autoimmunity, ameliorate innate/alloimmune graft rejection, and prevent recurrence of the disease. Herein, we discuss the therapeutic potential of stem cells derived from a variety of sources for the cure of T1D, for example, embryonic stem cells, induced pluripotent stem cells, bone marrow-derived hematopoietic stem cells, and multipotent mesenchymal stromal cells derived from bone marrow, umbilical cord blood, and adipose tissue. The benefits of combinatorial approaches designed to ensure the successful clinical translation of stem cell therapeutic strategies, such as approaches combining effective stem cell strategies with islet transplantation, immunomodulatory drug regimens, and/or novel bioengineering techniques, are also discussed. To conclude, the application of stem cell therapy in the cure for T1D appears extremely promising.
Concise Review: Carbon Nanotechnology: Perspectives in Stem Cell Research
Authors: Pryzhkova Marina V.
Published: April 2013

Carbon nanotechnology has developed rapidly during the last decade, and carbon allotropes, especially graphene and carbon nanotubes, have already found a wide variety of applications in industry, high-tech fields, biomedicine, and basic science. Electroconductive nanomaterials have attracted great attention from tissue engineers in the design of remotely controlled cell-substrate interfaces. Carbon nanoconstructs are also under extensive investigation by clinical scientists as potential agents in anticancer therapies. Despite the recent progress in human pluripotent stem cell research, only a few attempts to use carbon nanotechnology in the stem cell field have been reported. However, acquired experience with and knowledge of carbon nanomaterials may be efficiently used in the development of future personalized medicine and in tissue engineering.
Effects of Oral Intervention on Fluctuations in Exchange Rates: Evidence from Japan 1995-2011
Authors: Sakata Shun , Takeda Fumiko
Published: April 2013

Abstract: This paper studies the effects of oral interventions on the JPY/USD rate between 1995 and 2011. Traditionally, monetary authorities have intervened directly in foreign exchange markets. In recent years, however, actual interventions have been supplemented or supplanted by â€œoral interventionsâ€ to influence market expectations. In the Japanese case, monetary authorities did not directly intervene in the market from 2005 to August 2010. They conducted actual interventions only five times between 2010 and 2012, though Japan has been noted for ongoing oral intervention in recent years. Prior studies examining the impact of oral interventions provide mixed results regarding their effectiveness. Our study attempts to contribute to the literature by focusing not only on the speaker of oral interventions, but also on the content of the statements released. Using the event study methodology, we find that market participants give great credence to announcements by monetary authorities that strike a decidedly positive or negative tone about current exchange rates. In addition, market participants give great credence to statements by speakers who actually conduct exchange rate policy, including staff from the Ministry of Finance and people affiliated with the Bank of Japan.
Electrophysiology in Glaucoma - A Review
Authors: Goyal JL , Seetharam Sudha , Arora Ritu , Jain Parul
Published: April 2013

Glaucoma is a slowly progressive disease which might lead to irreversible loss of vision if not detected and treated early. Early diagnosis of glaucoma remains a challenge to the clinician. It is conceivable that early nerve damage can be detected only by a test which is sensitive to its dysfunction before structural changes occur. The purpose of this review is to highlight the role of various electrophysiological techniques in the assessment and diagnosis of glaucoma.
Unusual Case Report of Flat, Sharp and Pointed Metallic Foreign Body Traversing the Orbital Floor
Authors: Sharma Manish , Kalla Chandan , Kumar Kishore
Published: April 2013

Loss of vision in conjunction with intraorbital foreign bodies is largely a result of the initial trauma. We aim to report an unusual orbital injury in which a flat, sharp and pointed metallic foreign body (Blade of scissors around 8 cm in length) traversed within the periosteum of orbital floor diagonally entering at its anterio-medial aspect and going posteriorly & laterally up to inferior margin of lateral orbital wall. CT scan showed that there was no ocular damage and extra ocular muscles & optic nerve were also not injured. Management strategy is discussed in the report. Ocular movements were normal postoperatively and patient had a final visual outcome of 6/6.
Highly Efficient and Bendable Organic Solar Cells with Solution‐Processed Silver Nanowire Electrodes
Authors: Song Myungkwan , You Dae Sung , Lim Kyounga , Park Sujin , Jung Sunghoon , Kim Chang Su , Kim Dong‐Ho , Kim Do‐Geun , Kim Jongk‐Kuk , Park Juyun , Kang Yong‐Cheol , Heo Jinhee , Jin Sung‐Ho , Park Jong Hyun , Kang Jae‐Wook
Published: April 2013

Highly efficient and bendable organic solar cells (OSCs) are fabricated using solution‐processed silver nanowire (Ag NW) electrodes. The Ag NW films were highly transparent (diffusive transmittance ≈ 95% at a wavelength of 550 nm), highly conductive (sheet resistance ≈ 10 Ω sq−1), and highly flexible (change in resistance ≈ 1.1 ± 1% at a bending radius of ≈200 μm). Power conversion efficiencies of ≈5.80 and 5.02% were obtained for devices fabricated on Ag NWs/glass and Ag NWs/poly(ethylene terephthalate) (PET), respectively. Moreover, the bendable devices fabricated using the Ag NWs/PET films decrease slightly in their efficiency (to ≈96% of the initial value) even after the devices had been bent 1000 times with a radius of ≈1.5 mm.
Catalytic Saloplastics: Alkaline Phosphatase Immobilized and Stabilized in Compacted Polyelectrolyte Complexes
Authors: Tirado Patricia , Reisch Andreas , Roger Emilie , Boulmedais Fouzia , Jierry Loïc , Lavalle Philippe , Voegel Jean‐Claude , Schaaf Pierre , Schlenoff Joseph B. , Frisch Benoît
Published: April 2013

Novel biochemically active compact polyelectrolyte complexes (CoPECs) are obtained through a simple coprecipitation and compaction procedure. As shown for the system composed of poly(acrylic acid) (PAA) and poly(allylamine) (PAH) as polyelectrolytes and alkaline phosphatase (ALP) as enzyme, the enzyme can be firmly immobilized into these materials. The ALP not only remains active in these materials, but the matrix also enhances the specific activity of the enzyme while protecting it from deactivation at higher temperature. The presence of the matrix allows fine control and substantial enhancement of reaction rates by varying the salt concentration of the contacting solution or temperature. The excellent reusability, together with the ease of co‐immobilizing other useful components, such as magnetic particles, allowing facile handling of the CoPECs, makes these materials interesting candidates for variable scaffolds for the immobilization of enzymes for small‐ and large‐scale enzyme‐catalyzed processes.
Strontium Diffusion in Magnetron Sputtered Gadolinia‐Doped Ceria Thin Film Barrier Coatings for Solid Oxide Fuel Cells
Authors: Sønderby Steffen , Popa Petru Lunca , Lu Jun , Christensen Bjarke Holl , Almtoft Klaus Pagh , Nielsen Lars Pleth , Eklund Per
Published: April 2013

Strontium (Sr) diffusion in magnetron sputtered gadolinia‐doped ceria (CGO) thin films is investigated. For this purpose, a model system consisting of a screen printed (La,Sr)(Co,Fe)O3−δ (LSCF) layer, and thin films of CGO and yttria‐stabilized zirconia (YSZ) is prepared to simulate a solid oxide fuel cell. This setup allows observation of Sr diffusion by observing SrZrO3 formation using X‐ray diffraction while annealing. Subsequent electron microscopy confirms the results. This approach presents a simple method for assessing the quality of CGO barriers without the need for a complete fuel cell test setup. CGO films with thicknesses ranging from 250 nm to 1.2 μm are tested at temperatures from 850 °C to 1000 °C which yields an in‐depth understanding of Sr diffusion through CGO thin films that may be of high scientific and technical interest for implementation of novel fuel cell materials. Sr is found to diffuse along column/grain boundaries in the CGO films but by modifying the film thickness and microstructure the breaking temperature of the barrier can be increased.
Do Marketing Margins Change with Food Scares? Examining the Effects of Food Recalls and Disease Outbreaks in the U.S. Red Meat Industry
Authors: Capps Oral , Colin‐Castillo Sergio , Hernandez Manuel A.
Published: April 2013

This study examines the impact of different food scare events on marketing margins in the U.S. beef and pork industries. The authors analyze how market stresses induced by the Food Safety Inspection Service (FSIS) recalls and bovine spongiform encephalopathy (BSE) outbreaks affect price spreads and the extent of price transmission at the slaughter‐to‐wholesale and wholesale‐to‐retail levels. They use monthly national data for the period 1986–2008, which includes records of FSIS recalls of varying severity and BSE events in the United States and Canada. The authors account for immediate and delayed effects of food scares and for potential cross effects across industries and countries. The results indicate that beef and food recalls do not affect their corresponding price margins and overall food safety incidents have minor cross‐industry and cross‐country effects. However, BSE discoveries in the United States considerably affect marketing margins in the beef industry, particularly at the wholesale‐to‐retail level. Interestingly, subsequent discoveries had smaller impacts on price margins. Bovine spongiform encephalopathy outbreaks also appear to affect the extent of price transmission between wholesalers and retailers.
Pseudo two‐dimensional modeling of sediment build‐up in centrifuges: A compartment approach using compressional rheology
Authors: Spelter Lars E. , Nirschl Hermann , Stickland Anthony D. , Scales Peter J.
Published: April 2013

Both a new modeling approach and new experimental data for the sediment build‐up in centrifuges are presented. In semibatch apparatus, the suspension is continuously fed to the centrifuge, separating the particles inside the rotor and discharging the clarified liquid. The solid phase is removed once the capacity of the centrifuge is reached. The solids fraction of the sediment depends on the rheological properties of the cake. The sediment growth and consolidation throughout the process can be calculated using a pseudo two‐dimensional approach that takes into account particle‐size dependent settling, sediment compressibility, the centrifugal force field, and the geometry of the bowl. The predictions of the separation behavior and the particle‐size distributions of the sediment and overflow are compared with experimentally obtained results, showing improved accuracy when compared to simpler models. The model presented is applicable to all solid‐bowl centrifuges without conveying systems. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3843–3855, 2013
H∞ Control for a Class of Continuous‐time Switched Systems with State Constraints
Authors: Su Qingyu , Zhao Jun
Published: April 2013

This paper investigates the H∞ control problem for a class of continuous‐time switched systems subject to state constraints with an improved average dwell time. The state constraints are converted into state saturations by limiting the state in a unit hypercube. By employing this proposed improved average dwell time method, which takes into account different decay rates of a Lyapunov function related to an active subsystem according to whether the saturations occur or not, the resulting minimum of admissible average dwell time is smaller than the one of the standard average dwell time, which only considers the same decay rate regardless of whether the saturations occur or not. In addition, switched state feedback controllers are designed such that the closed‐loop switched system, subject to state constraints, is asymptotically stable and achieves a weighted L2‐gain. Sufficient conditions for H∞ control of the switched system with state constraints are derived before an application to a Pulse‐Width‐Modulation (PWM)‐driven boost converter is given to illustrate the applicability and the effectiveness of the proposed method.
A New Approach For Stability Analysis Of Time‐Dependent Switched Continuous‐Time Linear Systems
Authors: Xiang Weiming , Xiao Jian , Han Lu
Published: April 2013

In this paper, a new approach for stability analysis of time‐dependent switched linear systems is proposed. System equivalence is the main idea in this new approach, which derives a switched discrete linear parameter‐varying system from the switched continuous‐time linear switched system with interval dwell time, and the stability properties of the two corresponding systems are proved to be equivalent. Then, by applying a quadratic Lyapunov function approach for the equivalent switched discrete system, the stability of the switched continuous‐time linear system can be established without checking any average dwell time condition. Finally the computation complexity is analyzed, and mode incidence matrix is introduced to reduce the computation cost.
Raw material demand and sourcing options for the development of a bio‐based chemical industry in Europe.
Authors: Sanders Johan PM , Bos Harriëtte L
Published: April 2013

In this perspective it is shown that considerable amounts of fossil raw materials in the EU economy can be replaced by biomass by 2030 and 2050. Especially the additional demand from the chemical industry and part of the transportation fuels is investigated. Sufficient supply to accommodate the additional demand is achieved by a number of approaches: (i) by increasing the field yield of the main EU crops, including grassland; and (ii) by the application of biorefining technologies, which will enable efficient and economical use of biomass components for several purposes, for example, energy, animal feed, and chemical production. Especially the application of biorefinery technologies makes a broader crop choice possible, since all components present in the crop can be made to good use. It is concluded that in this way the EU can supply considerable amounts of its energy and raw material base, including the potential demand of the chemical industry, while at the same time decreasing its dependence on importing animal feed components from elsewhere. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
Intercultural education in Europe: policies, practices and trends
Authors: Faas Daniel , Hajisoteriou Christina , Angelides Panayiotis
Published: April 2013

European societies have become increasingly diverse as a result of legal and illegal migration flows, and educationists are facing the challenge of how to address the presence of migrant students. In recent years, there has been increasing activity at European level in the field of intercultural education despite the principle of subsidiarity. This article draws on 30 European level policy documents published within the last decade to analyse the dynamics influencing intercultural education in Europe. These include European Union institutions (such as European Commission, European Council, and Council of Ministers) and Council of Europe documents. Our discussions are situated within historical and contemporary European immigration policy developments. We argue that the main emphasis of recent European level policies and directives is on fostering social cohesion through incorporating migrant students. In so doing, European organisations have had to deal with arguments surrounding the legitimacy of European policy initiatives in the field of intercultural education.
Competitive opportunity and liberal culture: the significance of Scottish education in the twentieth century
Authors: Paterson Lindsay
Published: April 2013

Three of the great social ambitions of educational reform since the late nineteenth century are now seriously problematical. Although education does offer individuals a way of bettering themselves, we now know that it does little to change the terms of the competition among people who start from different social classes: it probably does not, by itself, affect relative social mobility. Education in advanced economies has little effect on overall rates of growth: it is now clear that the analogy between individual and economic development is untenable. And the main other option to these instrumental goals—that education should pass on the best that has been thought and said—is now deeply unfashionable with policy‐makers, radical activists and most shades of academic opinion. Scotland is a telling case of these shifts. In the past century, it has held quite firmly to all three older views, and has tried quite thoroughly to implement educational reforms in pursuit of them. Its experience is as good a demonstration as any that the first two ambitions—of social mobility and of economic development—cannot be realised by educational change alone. The country is also moving deliberately away from the third ambition, its old humanism of knowledge. The implications of this experience and these developments are discussed.
Middle attainers and 14–19 progression in England: half‐served by New Labour and now overlooked by the Coalition?
Authors: Hodgson Ann , Spours Ken
Published: April 2013

In the context of the international problem of ‘early school leaving’, this paper explores the issue of sustained participation in upper secondary education in England. It focuses in particular on the position of middle attainers, who constitute a large proportion of the cohort and whose progress will be vital in realising the government's goal of ‘Raising the Participation Age’ to 18 by 2015. The paper draws on evidence from national research undertaken as part of the Nuffield Review of 14–19 Education and Training in England and Wales and analysis of New Labour and Coalition policy between 2000–2012. It uses a three‐year local study of 2400 14‐ and 16‐year‐olds in an established school/college consortium to illustrate the effects of policy and practice on middle attainers. We argue that this important group of young people was ‘half‐served’ by New Labour, because of its incomplete and contradictory 14–19 reforms, and is now being ‘overlooked’ by Coalition policy because of its emphasis on high attainers. We conclude by suggesting a range of measures to support the 14+ participation, progression and transition of middle attainers in the English education and training system.
Moving house for education in the pre‐school years
Authors: Hansen Kirstine
Published: April 2013

This paper uses data from the Millennium Cohort Study (MCS) to examine house moves that take place in the pre‐school years, focusing on families who move for the education of their children. We present results showing that education‐ related house moves do indeed occur in the pre‐school years with particular types of parents making these education‐related moves to ensure their children attend a good primary school. We then examine whether this demand for high quality schooling is associated with a house price premia by linking the MCS data to Land Registry data and show that parents are prepared to pay significantly more to buy a house located near to better performing primary schools, even before their children reach school starting age. We interpret this as evidence of demand for school quality in the early years as parents (especially more educated and advantaged parents) ‘gear up’ their quest for what they perceive to be better schooling for their children before they start school.
Nothobranchius furzeri
Authors: Hartmann Nils , Reichwald Kathrin , Platzer Matthias , Englert Christoph
Published: April 2013

Der Türkise Prachtgrundkärpfling Nothobranchius furzeri lebt in saisonalen Tümpeln Afrikas. Durch Diapausen übersteht er die zum Teil sehr langen Trockenzeiten. Nach dem Schlüpfen zeigt er ein sehr schnelles Wachstum und ist nach vier bis fünf Wochen geschlechtsreif. Bestimmte Stämme von N. furzeri weisen eine Lebensspanne von lediglich drei bis vier Monaten auf, was die kürzeste Lebensspanne für ein Wirbeltier darstellt, das im Labor gehalten werden kann. Trotz seiner kurzen Lebensspanne zeigt N. furzeri typische Altersmarker auf morphologischer, verhaltensbiologischer und molekularer Ebene. So zeigen alte Tiere beispielsweise eine Verkürzung der Telomere sowie einen Verlust der Anzahl und Aktivität der Mitochondrien. Erste Kreuzungsexperimente haben gezeigt, dass es mindestens vier Bereiche im Genom von N. furzeri gibt, die etwas mit der unterschiedlichen Lebensspanne zu tun haben.
Warum Spinnen (nur) acht Beine haben
Authors: Khadjeh Sara , Turetzek Natascha , Pechmann Matthias , Prpic Nikola‐Michael
Published: April 2013

Die unterschiedliche Beinanzahl im Bauplan von Insekten und Spinnen wird als Modell genutzt, um Einblicke in die Genetik und Evolution von Bauplanunterschieden zu bekommen. Dabei spielen die Hox‐Gene eine wichtige Rolle: Insbesondere das Hox‐Gen Antennapedia hat während der Evolution offenbar seine Funktion und Interaktion mit bislang unbekannten Faktoren geändert.
New Limonoids from the Seeds of a Krishna Mangrove, Xylocarpus granatum
Authors: Chen Hongliang , Zhang Jing , Li Min‐Yi , Satyanandamurty Tirumani , Wu Jun
Published: April 2013

Two new mexicanolides, named granatumins H and I (1 and 2, resp.), and two phragmalins, named granatumins J and K (3 and 4, resp.), were isolated from the seeds of an Indian mangrove, Xylocarpus moluccensis, collected from the swamps of Krishna estuary, Andhra Pradesh. The structures of these limonoids were established on the basis of spectroscopic data. Granatumin J (3) is a highly oxidized phragmalin with five AcO groups, whereas granatumin K (4) is the first phragmalin found in nature with conjugated C(8)C(30) and C(14)C(15) bonds.
Chemical Composition and Antimicrobial Activity of Essential Oils from Chromolaena laevigata during Flowering and Fruiting Stages
Authors: Murakami Cynthia , Lago João H. G. , Perazzo Fábio F. , Ferreira Karen S. , Lima Marcos E. L. , Moreno Paulo R. H. , Young Maria C. M.
Published: April 2013

The chemical compositions and antimicrobial activities of essential oils from the leaves, stems, capitula, and cypselas of Chromolaena laevigata were evaluated at two different phenological stages, flowering and fruiting. Thirty‐eight compounds were identified in the crude oils by GC/MS. The sesquiterpene laevigatin was the major constituent of the leaf, capitulum, and cypsela oils, while the sesquiterpene spathulenol was the main component in the stem oils. The antimicrobial activities of the oils were evaluated against Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Stem oil obtained from Chromolaena laevigata during the fruiting stage generally showed the highest activity with minimum inhibitory concentration (MIC) values of 62.5 μg/ml against Candida albicans and S. aureus, and 500 μg/ml against P. aeruginosa and E. coli. Pure laevigatin exhibited MIC values of 500 and 125 μg/ml against C. albicans and S. aureus, respectively, indicating that this constituent could be responsible, at least in part, for the antimicrobial activities detected in the crude oils. More studies concerning the biological activities of isolated derivatives are required to improve our knowledge of the antimicrobial potential of volatile compounds present in native plants.
In vitro Leishmanicidal and Cytotoxic Activities of the Glycoalkaloids from Solanum lycocarpum (Solanaceae) Fruits
Authors: Abreu Miranda Mariza , Tiossi Renata Fabiane Jorge , da Silva Mariana Rosa , Rodrigues Kelly Cristina , Kuehn Christian Collins , Rodrigues Oliveira Luiz Gustavo , Albuquerque Sérgio , McChesney James Dewey , Lezama‐Davila Claudio Manuel , Isaac‐Marquez Angelica Patricia , Kenupp Bastos Jairo
Published: April 2013

Leishmaniasis is an infection caused by a protozoan parasite of the genus Leishmania and is the second most prevalent parasitic protozoal disease after malaria in the world. We report the in vitro leishmanicidal activity on promastigote forms of Leishmania amazonensis and cytotoxicity, using LLCMK2 cells, of the glycoalkaloids from the fruits of Solanum lycocarpum, determined by colorimetric methods. The alkaloidic extract was obtained by acid‐base extraction; solamargine and solasonine were isolated by silica‐gel chromatography, followed by reversed‐phase HPLC final purification. The alkaloidic extract, solamargine, solasonine, as well as the equimolar mixture of the glycoalkaloids solamargine and solasonine displayed leishmanicidal activity against promastigote forms of L. amazonensis, whereas the aglycone solasodine was inactive. After 24 and 72 h of incubation, most of the samples showed lower cytotoxicities (IC50 6.5 to 124 μM) as compared to leishmanicidal activity (IC50 1.1 to 23.6 μM). The equimolar mixture solamargine/solasonine was the most active with an IC50 value of 1.1 μM, after 72 h. Likewise, solamargine was the most active after 24 h with an IC50 value of 14.4 μM, both in comparison with the positive control amphotericin B.
MMPREDOX/NO Interplay in Periodontitis and Its Inhibition with Satureja hortensis L. Essential Oil
Authors: Zeidán‐Chuliá Fares , Neves de Oliveira Ben‐Hur , Gursoy Mervi , Könönen Eija , Fonseca Moreira José Cláudio , Gursoy Ulvi K. , Uitto Veli‐Jukka
Published: April 2013

Satureja hortensis L. is an aromatic plant with antibacterial and antibiofilm activities against periodontopathogens. Here, we attempted to find out whether the antioxidant properties of S. hortensis L. essential oil (EO) could be used to inhibit matrix metalloproteinase (MMP) activities and prevent the induction of cell death by a pro‐oxidant insult. First, a landscape analysis of MMP and REDOX/nitric oxide (NO)‐related genes was performed (MRN model), and array data from periodontitis patients were plotted over the newly developed model. Thereafter, the antigelatinolytic activity of S. hortensis L. EO and its preventive effect against hydrogen peroxide (H2O2)‐induced cell death were tested in vitro (HaCaT cells). Up‐regulation of MMP genes in the MRN network (except for MMP‐10, ‐15, ‐16, ‐20, ‐25, and ‐26) and differential expression of genes coding for antioxidant enzymes were found among others in periodontitis samples. MMP2 and MMP9 were central genes in the MRN network model. Moreover, treatments with 1 and 5 μl/ml of S. hortensis L. EO inhibited both MMP‐2 and MMP‐9 activities, and H2O2‐induced cell death in vitro. We concluded that S. hortensis L. EO could be a promising host‐modulating agent, since oxidative stress and excessive MMP expression/activity are typical hallmarks of periodontal pathogenesis.
Configurational Assignment of Secondary Hydroxyl Groups and Methyl Branches in Polyketide Natural Products through Bioinformatic Analysis of the Ketoreductase Domain
Authors: Kitsche Andreas , Kalesse Markus
Published: April 2013

Profile hidden Markov models (HMMs) were used to predict the configuration of secondary alcohols and α‐methyl branches of modular polyketides. Based on the configurations of two chiral centers in these polyketides, 78 ketoreductases were classified into four different types of polyketide producers. The identification of positions that discriminate between these protein families was followed by fitting six profile HMMs to the data set and the corresponding subsets, to model the conserved regions of the protein types. Ultimately, the profile HMMs described herein predict protein subtypes based on the complete information‐rich region; consequently, slight changes in a multiple sequence alignment do not significantly alter the outcome of this classification method. Additionally, Viterbi scores can be used to assess the reliability of the classification.
Light‐Induced Reduction of Cuprous Oxide in an Environmental Transmission Electron Microscope
Authors: Cavalca Filippo , Laursen Anders B. , Wagner Jakob B. , Damsgaard Christian D. , Chorkendorff Ib , Hansen Thomas W.
Published: April 2013

Photocatalysts for solar fuel production are subject to intensive investigation as they constitute one viable route for solar energy harvesting. Cuprous oxide (Cu2O) is a working photocatalyst for hydrogen evolution but it photocorrodes upon light illumination in an aqueous environment. Environmental transmission electron microscopy (ETEM) makes it possible to obtain insight into the local structure, composition and reactivity of catalysts in their working environment, which is of fundamental interest for sustainable energy research and is essential for further material optimization. Herein, photoreduction of Cu2O is studied in situ using a dedicated TEM specimen holder for light illumination.
Ultrasensitive SERS Detection of Lysozyme by a Target‐Triggering Multiple Cycle Amplification Strategy Based on a Gold Substrate
Authors: He Peng , Zhang Yan , Liu Lijun , Qiao Wenping , Zhang Shusheng
Published: April 2013

An ultrasensitive surface enhanced Raman scattering (SERS) method has been designed to selectively and sensitively detect lysozyme. The gold chip as the detection substrate, the aptamer‐based target‐triggering cascade multiple cycle amplification, and gold nanoparticles (AuNPs) bio‐barcode Raman probe enhancement on the gold substrate are employed to enhance the SERS signals. The cascade amplification process consists of the nicking enzyme signaling amplification (NESA), the strand displacement amplification (SDA), and the circular‐hairpin‐assisted exponential amplification reaction (HA‐EXPAR). With the involvement of an aptamer‐based probe, two amplification reaction templates, and a Raman probe, the whole circle amplification process is triggered by the target recognition of lysozyme. The products of the upstream cycle (NESA) could act as the “DNA trigger” of the downstream cycle (SDA and circular HA‐EXPAR) to generate further signal amplification, resulting in the immobility of abundant AuNPs Raman probes on the gold substrate. “Hot spots” are produced between the Raman probe and the gold film, leading to significant SERS enhancement. This detection method exhibits excellent specificity and sensitivity towards lysozyme with a detection limit of 1.0×10−15 M. Moreover, the practical determination of lysozyme in human serum demonstrates the feasibility of this SERS approach in the analysis of a variety of biological specimens.
Precise Control of Intramolecular Charge‐Transport: The Interplay of Distance and Conformational Effects
Authors: Schubert Christina , Wielopolski Mateusz , Mewes Lars‐Hendrik , de Miguel Rojas Gustavo , van der Pol Cornelia , Moss Kathryn C. , Bryce Martin R. , Moser Jacques E. , Clark Timothy , Guldi Dirk M.
Published: April 2013

A new series of donor–bridge–acceptor (D–B–A) compounds consisting of π‐conjugated oligofluorene (oFL) bridges between a ferrocene (Fc) electron‐donor and a fullerene (C60) electron‐acceptor have been synthesized. In addition to varying the length of the bridge (i.e., mono‐ and bi‐fluorene derivatives), four different ways of linking ferrocene to the bridge have been examined. The Fc moiety is linked to oFL: 1) directly without any spacer, 2) by an ethynyl linkage, 3) by a vinylene linkage, and 4) by a p‐phenylene unit. The electronic interactions between the electroactive species have been characterized by cyclic voltammetry, absorption, fluorescence, and transient absorption spectroscopy in combination with quantum chemical calculations. The calculations reveal exceptionally close energy‐matching between the Fc and the oFL units, which results in strong electronic‐coupling. Hence, intramolecular charge‐transfer may easily occur upon exciting either the oFLs or Fcs. Photoexcitation of Fc–oFL–C60 conjugates results in transient radical‐ion‐pair states. The mode of linkage of the Fc and FL bridge has a profound effect on the photophysical properties. Whereas intramolecular charge‐separation is found to occur rather independently of the distance, the linker between Fc and oFL acts (at least in oFL) as a bottleneck and significantly impacts the intramolecular charge‐separation rates, resulting in beta values between βCS 0.08 and 0.19 Å−1. In contrast, charge recombination depends strongly on the electron‐donor–acceptor distance, but not at all on the linker. A value of βCR (0.35±0.01 Å−1) was found for all the systems studied. Oligofluorenes prove, therefore, to be excellent bridges for probing how small structural variations affect charge transport in D–B–A systems.
An Efficient Method to Separate Sc3N@C80Ih and D5h Isomers and Sc3N@C78 by Selective Oxidation with Acetylferrocenium [Fe(COCH3C5H4)Cp]+
Authors: Cerón Maira R. , Li Fang‐Fang , Echegoyen Luis
Published: April 2013

Based on the different oxidation potentials of endohedral fullerenes Sc3N@C80 Ih and D5h and Sc3N@C78, an efficient and useful method that avoids HPLC has been developed for their separation. Selective chemical oxidation of the Sc3N@D5h‐C80 isomer and Sc3N@C78 by using an acetylferrocenium salt [Fe(COCH3C5H4)Cp]+ followed by column chromatographic separation and reduction with CH3SNa resulted in the isolation of pure Sc3N@Ih‐C80, Sc3N@C78, and a mixture of Sc3N@D5h‐C80 and Sc3N@C68.
Chemoselectivity Control in the Reactions of 1,2‐Cyclic Sulfamidates with Amines
Authors: Mata Lara , Avenoza Alberto , Busto Jesús H. , Peregrina Jesús M.
Published: April 2013

Although 1,2‐cyclic sulfamidates derived from α‐methylisoserine undergo nucleophilic displacement at the quaternary center, to the best of our knowledge their behavior with amines as nucleophiles has never been explored. We have found that a broad range of amines can be used, demonstrating the scope of the reaction, and that excellent control of the chemoselectivity can be achieved. Application of this methodology for the synthesis of a chiral α,β‐diamino acid and an important piperazinone heterocycle is also presented. Additionally, we have found that DMF and DMSO behave not only as polar aprotic solvents but also as O‐nucleophilic reagents, allowing the incorporation of an oxygen atom at a quaternary center of the electrophile, with inversion of configuration.
Why Do Cycloaddition Reactions Involving C60Prefer [6,6] over [5,6] Bonds?
Authors: Fernández Israel , Solà Miquel , Bickelhaupt F. Matthias
Published: April 2013

The origin of the experimentally known preference for [6,6] over [5,6] bonds in cycloaddition reactions involving C60has been computationally explored. To this end, the Diels–Alder reaction between cyclopentadiene and C60has been analysed by means of the recently introduced activation strain model of reactivity in combination with the energy decomposition analysis method. Other issues, such as the aromaticity of the corresponding transition states, have also been considered. These results indicate that the major factor controlling the observed regioselectivity is the more stabilising interaction between the deformed reactants in the [6,6] reaction pathway along the entire reaction coordinate.
Doped Graphene as a Metal‐Free Carbocatalyst for the Selective Aerobic Oxidation of Benzylic Hydrocarbons, Cyclooctane and Styrene
Authors: Dhakshinamoorthy Amarajothi , Primo Ana , Concepcion Patricia , Alvaro Mercedes , Garcia Hermenegildo
Published: April 2013

Nitrogen (N)‐, boron (B)‐, and boron,nitrogen (B,N)‐doped graphene (G) act as carbocatalysts, promoting the aerobic oxidation of the benzylic positions of aromatic hydrocarbons and cyclooctane to the corresponding alcohol/ketone mixture with more than 90 % selectivity. The most active material was the co‐doped (B,N)G, which, in the absence of solvent and with a substrate/(B,N)G ratio of 200, achieved 50 % tetralin conversion in 24 h with a alcohol/ketone selectivity of 80 %. An FT‐Raman spectroscopic study of a sample of (B,N)G heated at 100 °C in the presence of oxygen revealed new bands that disappeared upon evacuation and that have been attributed to hydroperoxide‐like species formed on the G sheet based on the isotopic shift of the peak from 819 to 779 cm−1when18O2was used as the oxidizing reagent. Furthermore, (B)G and (N)G exhibited high catalytic activity in the aerobic oxidation of styrene to benzaldehyde (BA) in 4 h. However, the product distribution changed over time and after 10 h a significant percentage of styrene oxide (SO) was observed under the same conditions. The use of doped G as catalyst appears to offer broad scope for the aerobic oxidation of benzylic compounds and styrene, for which low catalyst loading, mild reaction temperatures, and no additional solvents are required.
Modifiable risk behaviors in patients with head and neck cancer
Authors: Sivasithamparam Janani , Visk Carly A. , Cohen Ezra E. W. , King Andrea C.
Published: April 2013

BACKGROUND

Use of tobacco products, excessive alcohol consumption, and high‐risk sexual behaviors increase the risk of developing head and neck cancer and impacts treatment effectiveness after diagnosis. This study examined smoking and engagement in other modifiable behavioral risk factors and human papillomavirus (HPV) status in patients with head and neck cancer in order to facilitate identification and foster development of targeted interventions in high‐risk patients.

METHODS

Participants were 102 patients with head and neck cancer at a large urban cancer center who completed a self‐report background and health questionnaire and provided a saliva sample for determination of the long‐acting nicotine metabolite cotinine.

RESULTS

Compared with former and never‐smokers, current smokers were less educated, less likely to be married or living with a partner, and consumed more alcohol. Cotinine analysis indicated that 4 of 16 (25%) patients who denied past‐month cigarette use misrepresented their true smoking status. Of patients with oropharyngeal cancer, 74% were confirmed as HPV‐positive, and compared with HPV‐negative patients, they were younger, more likely to be married/partnered and of Caucasian race, and reported more past vaginal and oral sexual partners. Only one‐third of HPV‐positive patients were aware of their HPV disease status.

CONCLUSIONS

Cigarette smoking is associated with engagement in other modifiable risk factors in patients with head and neck cancer. Self‐report measures of smoking may not accurately depict true smoking status. HPV‐positive cancer patients were more likely to endorse a history of multiple sexual partners. Regular screening and targeted interventions for these distinct risk factors are warranted. Cancer 2013;119:2419‐2426. © 2013 American Cancer Society.
Use of touch imprint cytology as a simple method to enrich tumor cells for molecular analysis
Authors: Dogan Snjezana , Becker Jillian C. , Rekhtman Natasha , Tang Laura H. , Nafa Khedoudja , Ladanyi Marc , Klimstra David S.
Published: April 2013

BACKGROUND

A relative excess of nonneoplastic cells in frozen carcinoma samples is often a cause of false‐negative results in molecular assays. Given the greater cohesiveness of epithelial tumor cells compared with nonneoplastic epithelium and mesenchymal stroma, the authors hypothesized that tumor procurement by touch imprinting would provide a simple, cost‐effective method of obtaining enriched neoplastic cells compared with frozen whole‐tumor samples.

METHODS

Eleven adenocarcinomas with known KRAS gene mutations were tested. Two sets of 8 touch imprint (TP) slides and 1 frozen whole‐tumor sample (FS), both with a corresponding hematoxylin and eosin‐stained slide, were obtained from each tumor. DNA from unstained TP and FS samples was tested for KRAS exon 2 mutations by Sanger sequencing. The percentage of carcinoma cells was determined by light microscopy of hematoxylin and eosin‐stained slides. The fold increase in the mutant‐enriched DNA in TP versus FS samples was determined by calculating the height ratio between the mutant and wild‐type peaks on the sequencing electropherogram.

RESULTS

Using light microscopy, TP demonstrated a 1.1‐fold to 3.5‐fold (mean, 1.8‐fold) enrichment in neoplastic cells compared with the FS. The mutant–to–wild‐type peak height ratio was 1.4‐fold to 7.1‐fold (mean, 3.1‐fold) higher in TP compared with the corresponding FS samples. The average amount of extracted DNA ranged from 145 ng to 7.9 μg per TP slide.

CONCLUSIONS

The procurement of carcinoma samples by TP is rapid, simple, and inexpensive; consistently provides a tumor‐enriched sample; is an excellent source of high‐quality tumor DNA; and could compensate for the relatively low sensitivity of direct sequencing. Cancer (Cancer Cytopathol) 2013;121:354–360. © 2013 American Cancer Society.
Single‐Step Sulfo‐Selenization Method to Synthesize Cu2ZnSn(SySe1−y)4 Absorbers from Metallic Stack Precursors
Authors: Fairbrother Andrew , Fontané Xavier , Izquierdo‐Roca Victor , Espindola‐Rodriguez Moises , López‐Marino Simon , Placidi Marcel , López‐García Juan , Pérez‐Rodríguez Alejandro , Saucedo Edgardo
Published: April 2013

Pentenary Cu2ZnSn(SySe1−y)4 (kesterite) photovoltaic absorbers are synthesized by a one‐step annealing process from copper‐poor and zinc‐rich precursor metallic stacks prepared by direct‐current magnetron sputtering deposition. Depending on the chalcogen source—mixtures of sulfur and selenium powders, or selenium disulfide—as well as the annealing temperature and pressure, this simple methodology permits the tuning of the absorber composition from sulfur‐rich to selenium‐rich in one single annealing process. The impact of the thermal treatment variables on chalcogenide incorporation is investigated. The effect of the S/(S+Se) compositional ratio on the structural and morphological properties of the as‐grown films, and the optoelectronic parameters of solar cells fabricated using these absorber films is studied. Using this single‐step sulfo‐selenization method, pentenary kesterite‐based devices with conversion efficiencies up to 4.4 % are obtained.
Paradoxical MAPK‐activation in response to treatment with tyrosine kinase inhibitors in CML: Flow cytometry loses track
Authors: Schnetzke Ulf , Fischer Mike , Frietsch Jochen J. , Finkensieper Andreas , Clement Joachim H. , Hochhaus Andreas , Rosée Paul La
Published: April 2013

Background

Paradoxical activation of the MAP‐kinases, ERK1, and ERK2 (ERK1/2) is observed in CML cell lines and primary CML patient cells treated with tyrosine kinase inhibitors (TKI) in vitro. The commonly accepted assumption is that activated ERK1/2 is key regulators of survival of leukemic cells treated with kinase inhibitors. Hence, paradoxical ERK1/2‐activation may trigger resistance in vivo, which yet has to be shown. We therefore sought to establish a flow cytometric assay that enables us to measure paradoxical TKI‐induced ERK1/2‐activation on a single cell basis in primary CML cells.

Methods

Side‐by‐side Western blot and intracellular flow cytometry (FCM) after in vitro exposure of cell lines and primary cells to nilotinib were performed. Detailed analysis of pre‐analytical factors and the issue of compartmentalization of phosphorylated ERK1/2 by confocal laser scanning microscopy were performed.

Result

Results were conflicting in that pERK‐activation was robustly detected in Western blot assays, but not when cells were analyzed by FCM despite well functioning positive and negative controls. This is in contrast to experiments on other targets such as phospho‐CrkL, where also in our hands TKI‐dependent inhibition of phosphorylation is trackable by both Western blot and FCM assays.

Conclusions

To our knowledge this is the first report of discordant results in phospho‐protein analysis in TKI‐treated cells analyzed by Western blot vs. FCM. We speculate that a substance specific interaction interferes with fluorescence dependent methods seeking to track phosphorylated ERK1/2 in TKI‐treated cells. © 2013 International Clinical Cytometry Society.