bluuebunny/crossref_metadata_2025 huggingface dataset:
Avaliação da coagulação plasmática e plaquetometria em cães não infectados e infectados experimentalmente com Ehrlichia spp.
Authors: Xavier M.S. , Almosny N.R.P. , Nascimento M.D. , Silva G.V.O. , Botelho G.G.
Published: November 2009

Avaliou-se a ocorrência de distúrbios na coagulação plasmática e na plaquetometria de cães infectados por Ehrlichia spp., durante 15 semanas após o contágio. Doze cães, entre machos e fêmeas, nascidos em estação experimental e com idades entre um e dois anos, foram usados no experimento. Nove cães foram infectados experimentalmente com sangue de cão naturalmente portador de Ehrlichia spp. e três foram mantidos como controle. As alterações na coagulação plasmática não diferiram entre cães infectados e não infectados. A plaquetometria oscilou durante as 15 semanas entre 61x10³/μL e 830x10³/μL, e o menor valor médio foi de 113x10³/μL na sexta semana após a infecção. Concluiu-se que a coagulação plasmática não apresentou alterações significativas nas 15 semanas após infecção e que a contagem plaquetária oscilou entre valores normais, elevados e reduzidos durante esse período.
A esquerda ontem e hoje: o dilema entre igualdade e liberdade
Authors: Coelho Maria Francisca Pinheiro
Published: November 2009

Este artigo discorre sobre as idéias da Esquerda na década de 1960 e as mudanças de paradigmas a partir da década de 1990, após a queda do Muro de Berlim e o colapso do socialismo real. Aborda um conflito que perpassa a história do socialismo: a questão dos direitos civis. Analisa também os dilemas da esquerda ontem e hoje, com ênfase na relação entre política e liberdade. Sugere que concomitante com a defesa da justiça social, a identidade de uma esquerda contemporânea se define pela defesa da liberdade como valor fundamental e essência da política.
A política democrática da sustentabilidade: os modelos deliberativo e associativo de democracia ambiental
Authors: Lenzi Cristiano Luis
Published: November 2009

A realização da sustentabilidade ambiental, usualmente, é vista como exigindo um aprofundamento do processo democrático. No entanto, a relação entre democracia e sustentabilidade ambiental não envolve apenas uma relação de simbiose, mas pode envolver uma série de desafios que muitas vezes não são reconhecidos por aqueles que defendem essa aproximação. Tendo em vista as questões que essa relação pode suscitar, o texto busca examinar justamente os limites e possibilidades que nascem desse encontro. Para isso, serão analisados no artigo dois modelos de democracia ambiental. No primeiro caso, será examinada a relação entre sustentabilidade e democracia deliberativa (ou discursiva) e, no segundo, a relação que pode ser estabelecida entre sustentabilidade ambiental e democracia associativa. Como veremos, esses modelos possibilitam vislumbrar dois tipos de democracia ambiental e, também, duas formas de se imaginar os principais traços uma política democrática da sustentabilidade.
Phase separation in non-ionic surfactant Triton X-100 solutions in the presence of phenol
Authors: Kulichenko Sergey , Doroschuk Volodymyr , Gonta Natalia
Published: November 2009

The influence of concentration conditions and acidity on the phase separation in non-ionic surfactants Triton X-100 solutions in the presence of phenol was investigated. It was shown that the addition of small amounts of phenol results in the decrease of the cloud point temperature of Triton X-100 solutions. On the other hand, the addition of phenol into the investigated system resulted in the decrease of the hydration values of surfactant-rich phases and the increase of their hydrophobicity. The extraction degree and distribution coefficient of phenol between the water and the surfactant-rich phases were studied. On the basis of data obtained the molar parts of water, phenol and Triton X-100 in the non-ionic surfactant-rich phases formed at different concentration conditions were calculated. Possibilities of the application of phenol-induced micellar extraction for microcomponents preconcentration were estimated.
Anodic reactions of sulphate in molten salts
Authors: Ambrová Marta , Fellner Pavel , Thonstad Jomar
Published: November 2009

Electrochemical behaviour of sulphate under anodic polarization in molten sodium chloride, cryolite and sodium fluoride was investigated by cyclic voltammetry and chronopotentiometry at the temperatures of 820°C, 1010°C, and 1000°C, respectively. Using a platinum working electrode, two waves were observed on the chronopotentiograms in the systems: NaCl-Na2SO4 and Na3AlF6-Na2SO4. The first wave was attributed to the formation of oxygen. The second wave probably originated from the reaction of oxygen with platinum, or from oxidation of SO3 decomposition products. Three waves were observed for the anodic process of sulphate ions dissolved in molten sodium fluoride. The first wave was attributed to the formation of oxygen. The second and the third wave were attributed to the formation of PtO and PtO2. This conclusion was supported by cyclic voltammetry experiments of the in-situ formed sulphide in molten NaCl at 820°C and by chronopotentiometry on a gold working electrode in the system NaCl-Na2SO4, where no anodic wave was observed.
Immobilization of urease in poly(1-vinyl imidazole)/poly(acrylic acid) network
Authors: Şenel Mehmet , Coşkun Agah , Fatih Abasıyanık M. , Bozkurt Ayhan
Published: November 2009

In this study, urease was immobilized in a polymer network obtained by complexation of poly(1-vinyl imidazole) (PVI) with poly(acrylic acid) (PAA). Preparation of the polymer network was monitored by FT-IR spectroscopy. Scanning electron microscopy (SEM) revealed that enzyme immobilization had a strong effect on film morphology. Proton conductivity of the PVI/PAA network was measured via impedance spectroscopy under humidified conditions. Values of the Michaelis-Menten constant (K M) for immobilized urease were higher than for the free enzyme, indicating a decreased affinity of the enzyme to its substrate. The basic characteristics (pHopt, pHstability, T opt, T stability, reusability, and storage stability) of immobilized urease were determined. The results show that the PAA/PVI polymer network is suitable for enzyme immobilization.
Governance of or through culture?
Authors: Karaca Banu
Published: November 2009

The notion of culture has loomed large in discourses and polemics regarding European integration and immigration in the European framework. While culture, as in fundamental cultural difference, is identified as the source of contemporary political quandaries, its incarnation as intercultural dialogue is conceived as their solution. Drawing on fieldwork conducted in the arts settings of Berlin and Istanbul, this article elucidates how this type of "culture talk" intersects with recent cultural policy formations in the European Union and the national arenas of Germany and Turkey. Much of the political productivity of culture arises from a constant slippage between the different, often contradictory, meanings accorded to the culture-concept. This extension of the "rhetoric of culture" engenders a shift from a governance of culture to one through culture by relaying an array of pressing political concerns from the realm of social and economic policy to that of culture in the sense of artistic expression.
Molecular biology of familial and sporadic vestibular schwannomas: implications for novel therapeutics
Authors: Sughrue Michael E. , Yeung Andrea H. , Rutkowski Martin J. , Cheung Steven W. , Parsa Andrew T.
Published: November 2009

Vestibular schwannomas (VSs) are benign tumors arising from the sheath of cranial nerve VIII. The pathogenesis underlying most familial and sporadic VSs has been linked to a mutation in a single gene, the neurofibromin 2 (NF2) gene located on chromosome 22, band q11–13.1. In this review, the authors summarized what is known about the epidemiology of NF2 mutations and patients with VSs. The authors also discuss the function of the NF2 gene product, merlin, and describe the known and hypothetical effects of genetic mutations that lead to merlin dysfunction on a broad variety of cellular and histological end points. A better understanding of the molecular pathobiology of VSs may lead to novel therapeutics to augment current modalities of treatment while minimizing morbidity.
Beyond audiofacial morbidity after vestibular schwannoma surgery
Authors: Sughrue Michael E. , Yang Isaac , Aranda Derick , Rutkowski Martin J. , Fang Shanna , Cheung Steven W. , Parsa Andrew T.
Published: November 2009

Object

Outcomes following vestibular schwannoma (VS) surgery have been extensively described; however, complication rates reported in the literature vary markedly. In addition, the majority of reports have focused on outcomes related to cranial nerves (CNs) VII and VIII. The objective of this study was to analyze reported morbidity unrelated to CNs VII and VIII following the resection of VS.

Methods

The authors performed a comprehensive search of the English language literature, identifying and aggregating morbidity and death data from patients who had undergone microsurgical removal of VSs. A subgroup analysis based on surgical approach and tumor size was performed to compare rates of CSF leakage, vascular injury, neurological deficit, and postoperative infection.

Results

One hundred articles met the inclusion criteria, providing data for 32,870 patients. The overall mortality rate was 0.2% (95% CI 0.1–0.3%). Twenty-two percent of patients (95% CI 21–23%) experienced at least 1 surgically attributable complication unrelated to CNs VII or VIII. Cerebrospinal fluid leakage occurred in 8.5% of patients (95% CI 6.9–10.0%). This rate was markedly increased with the translabyrinthine approach but was not affected by tumor size. Vascular complications, such as ischemic injury or hemorrhage, occurred in 1% of patients (95% CI 0.75–1.2%). Neurological complications occurred in 8.6% of cases (95% CI 7.9–9.3%) and were less likely with the resection of smaller tumors (p < 0.0001) and the use of the translabyrinthine approach (p < 0.0001). Infections occurred in 3.8% of cases (95% CI 3.4–4.3%), and 78% of these infections were meningitis.

Conclusions

This study provides statistically powerful data for practitioners to advise patients about the published risks of surgery for VS unrelated to compromised CNs VII and VIII.
High-definition fiber tracking guidance for intraparenchymal endoscopic port surgery
Authors: Fernandez-Miranda Juan C. , Engh Johnathan A. , Pathak Sudhir K. , Madhok Ricky , Boada Fernando E. , Schneider Walter , Kassam Amin B.
Published: November 2009

The authors have applied high-definition fiber tracking (HDFT) to the resection of an intraparenchymal dermoid cyst by using a minimally invasive endoscopic port. The lesion was located within the mesial frontal lobe, septal area, hypothalamus, and suprasellar recess. Using high-dimensional (256 directions) diffusion imaging, more than 250,000 fiber tracts were imaged before and after surgery. Trajectory planning using HDFT in a computer model was used to facilitate cannulation of the cyst with the endoscopic port. Analysis of the proposed initial surgical route was overlaid onto the fiber tracts and was predicted to produce substantial disruption to prefrontal projection fibers (anterior limb of the internal capsule) and the cingulum. Adjustment of the cannulation entry point 1 cm medially was predicted to cross the corpus callosum instead of the anterior limb of the internal capsule or the cingulum. Following cyst resection performed using endoscopic port surgery, postoperative imaging demonstrated accurate cannulation of the lesion, with improved quantitative signal from both the anterior limb of the internal capsule and the cingulum. The observed fiber preservation from the cingulum and the anterior limb of the internal capsule, with minor injury to the corpus callosum, was in close agreement with preoperative trajectory modeling. Comparison of pre- and postoperative HDFT data facilitated quantification of the benefits and costs of the surgical trajectory. Future studies will help to determine whether HDFT combined with endoscopic port surgery facilitates anatomical and functional preservation in such challenging cases.
Research in Medical College: Raison d'Etre
Authors: Yunus Emran Bin
Published: November 2009

doi: 10.3329/jcmcta.v18i1.3810Journal of Chittagong Medical College Teachers' Association 2007: 18(1):1-2
Surgical emphysema after tonsillectomy
Authors: Anwar Mostafa Mahfuzul , Bhattacharjee Nilakanta
Published: November 2009

doi: 10.3329/jcmcta.v18i1.3819Journal of Chittagong Medical College Teachers' Association 2007: 18(1):32-34
Sociodemographic pattern of drug abuser in the port city, Chittagong
Authors: Hasan Md Shafiul , Islam Md Azizul , Islam Md Monirul
Published: November 2009

doi: 10.3329/jcmcta.v18i2.3822Journal of Chittagong Medical College Teachers' Association 2007: 18(2):4-6
Colonoscopy: A study of findings in 332 patients
Authors: Sayeed Md Abu , Islam Rabiul , Siraji Dilruba , Hoque Md Gofranul , Mohsen AQM
Published: November 2009

Key words: colonoscopy; abdominal pain; lower GI bleeding; mass lesion; therapeutic yielddoi: 10.3329/jcmcta.v18i2.3833Journal of Chittagong Medical College Teachers' Association 2007: 18(2):28-31
Methotrexate induced neutropenia: A case report
Authors: Ahmed Syed Mozaffor , Salek AK Mohammed , Ahsanullah Md , Hasan Suzon Al
Published: November 2009

doi: 10.3329/jcmcta.v18i2.3837Journal of Chittagong Medical College Teachers' Association 2007: 18(2):47-48
Bio-psycho-social management model: Role of liaison psychiatry
Authors: Ahmed Syed Kamaluddin
Published: November 2009

doi: 10.3329/jcmcta.v19i1.3841Journal of Chittagong Medical College Teachers' Association 2008: 19(1):1-3
Association of chalamydia trachomitis infection in patients with tubal factor infertility
Authors: Banu Jesmine , Das Shakti , Fatima Parveen , Sultana Rozi
Published: November 2009

Key words: chalamydia trachomitis; infertility; tubal factordoi: 10.3329/jcmcta.v19i1.3842Journal of Chittagong Medical College Teachers' Association 2008: 19(1):4-7
Forecasting Extinctions: Uncertainties and Limitations
Authors: Ladle Richard  J.
Published: November 2009

Extinction forecasting is one of the most important and challenging areas of conservation biology. Overestimates of extinction rates or the extinction risk of a particular species instigate accusations of hype and overblown conservation rhetoric. Conversely, underestimates may result in limited resources being allocated to other species/habitats perceived as being at greater risk. In this paper I review extinction models and identify the key sources of uncertainty for each. All reviewed methods which claim to estimate extinction probabilities have severe limitations, independent of if they are based on ecological theory or on rather subjective expert judgments.
Creating Synergies from Renewable Energy Investments, a Community Success Story from Lolland, Denmark
Authors: Magnoni Silvia , Bassi Andrea M.
Published: November 2009

The island of Lolland is a showcase example of a remote local community being able to stand up to the challenges of facing environmental and social consequences of climate change while creating economic opportunities. This island has had many years of experience in implementing renewable energy (RE) projects as a way to combating peripheral poverty and promoting economic growth in a relatively remote area. The development strategy lies within the unique concept of Lolland Community Testing Facilities (CTF), which creates a forum between the private sector, research institutions and local political authorities by exploiting synergies among green investments and providing an international testing and demonstration platform for renewable energy technology and products. The present paper aims at giving an overview of integrated longer term energy planning based on Lolland CTF, its components and main features, while highlighting those critical characteristics that could make the CTF model successful and relevant for RE-based local development worldwide.
3-[Benzyl-(3,5-dimethyl-pyrazol-1-ylmethyl)-amino]-propionitrile
Authors: Herrag Leila , Touzani Rachid , Ramdani Abdelkrim , Hammouti Belkheir
Published: November 2009

The products of aza-type Michael addition, i.e., β-amino carbonyl compounds and their derivatives, are often used as peptide analogs or precursors of optically active amino acids, amino alcohols, diamines, and lactams [1].[...]
Synthesis and physical characterization of 1-(2,4-dimethoxyphenyl)-4-(4-nitrophenyl)-3-phenoxyazetidin-2-one
Authors: Jarrahpour A. A. , Jalbout A. F. , Rezaei S.
Published: November 2009

In this paper we propose the synthesis of 1-(2,4-dimethoxyphenyl)-4-(4-nitrophenyl)-3- phenoxyazetidin-2-one as a new monocyclic β-lactam. Its structure has been confirmed by IR, 1H-NMR, 13C-NMR and Mass spectroscopic data. In addition to its synthesis we present AM1 calculations to characterize the physical properties of the molecule.
(4Z)-1-Benzyl (1,3-Dibenzyl)-4-(2-oxopropylidene)-1,3,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one
Authors: Said Ould Mohamed Sidya Mohamed , Rachid Bouhfid , Joly Nicolas , Lequart Vincent , Martin Patrick , Massoui M. , Essassi El Mokhtar
Published: November 2009

We describe in this work the synthesis of new benzodiazepine derivatives susceptible to possess various pharmacological activities.[...]
1-Nitro-3-[(phenylsulfonyl)methyl]benzene
Authors: Grohmann Daniel G. , Hathaway Bruce A.
Published: November 2009

In the course of our work to prepare inhibitors of the enzyme dihydrofolate reductase, we desired to prepare sulfone analogues of some previously reported sulfides [1, 2].[...]
1-Nitro-3-[(benzylsulfonyl)methyl]benzene
Authors: Grohmann Daniel G. , Hathaway Bruce A.
Published: November 2009

In the course of our work to prepare inhibitors of the enzyme dihydrofolate reductase, we desired to prepare sulfone analogues of some similar sulfides [1, 2].[...]
3-[(Benzylsulfonyl)methyl]aniline hydrochloride
Authors: Grohmann Daniel G. , Hathaway Bruce A.
Published: November 2009

In the course of our work to prepare inhibitors of the enzyme dihydrofolate reductase, we desired to prepare sulfone analogues of some similar sulfides [1, 2].[...]
Synthesis of 2-(1,4-oxazino[2,3-b]quinoxalin-4-yl)ethanol
Authors: Obafemi Craig A. , Pfleiderer Wolfgang , Taiwo Festus
Published: November 2009

A mixture of 2,3-dichloroquinoxaline 1[1] (5.0 g, 25 mmol) and diethanolamine 2 (12 mL, 125 mmol) was heated to 130° C for 3 h, with magnetic stirring.[...]
Synthesis, Structural Studies and Antitumoral Evaluation of C-6 Alkyl and Alkenyl Side Chain Pyrimidine Derivatives S
Authors: Krištafor Svjetlana , Gazivoda Kraljević Tatjana , Makuc Damjan , Plavec Janez , Šuman Lidija , Kralj Marijeta , Raić-Malić Silvana
Published: November 2009

The synthetic route for introduction of fluorophenylalkyl (compounds 5, 7, 14 and 15) and fluorophenylalkenyl (compounds 4E and 13) side chains at C-6 of the pyrimidine nucleus involved the lithiation of the pyrimidine derivatives 1, 2 and 11 and subsequent nucleophilic addition or substitution reactions of the organolithium intermediate thus obtained with 2-fluorophenylacetone, 4-fluoroacetophenone or ethyl 4-fluorobenzoate as electrophiles. The structures of novel compounds were confirmed by 1H-, 19F- and 13C-NMR and MS. Compounds 8 and 10 containing unsaturated fluorophenylalkyl side chains showed better inhibitory effect than their saturated fluorophenylalkylated pyrimidine counterparts 7 and 9. A conformational study based on NOE enhancements showed the importance of the double bond and substitution in the side chain for the conformational preferences in relation to inhibitory activity. Among all tested compounds, C-5 furyl (12) and phenyl (13 and 15) substituted pyrimidine derivatives showed significant cytostatic activities against all tested tumor cell lines.
Aliskiren: Just a New Drug for Few Selected Patients or an Innovative Molecule Predestinated to Replace Arbs and Ace-Inhibitors?
Authors: Novo Salvatore , Fazio Giovanni , Raccuglia Elena
Published: November 2009

The renin-angiotensin-aldosterone system (RAAS) plays a dominant role in the pathophysiology of hypertension, diabetes mellitus, chronic kidney disease and chronic heart failure. Therefore, drugs that block key components of the RAAS such as ACE inhibitors (ACEI) and angiotensin receptor blockers (ARBs) have gained wide clinical use for these indications. Despite progress, the morbidity and mortality of patients treated with ACEI or ARBs remain high. Aliskiren (Tekturna, Rasilez) is the first orally active inhibitor of renin approved for clinical use as an antihypertensive agent. The development program has established that at the licensed doses of 150 mg and 300 mg. Aliskiren is effective either as monotherapy or in combination with drugs from the other major classes. In this review we analyze and review the information already gained with Aliskiren, raises questions regarding the advantages of DRIs as monotherapy compared to marketed ACEIs and ARBs, their potential added value in combination with other RAAS modulators and other still unproven benefits in relation to prorenin and renin receptor biology.
On a Symmetric, Nonlinear Birth-Death Process with Bimodal Transition Probabilities
Authors: Di Crescenzo Antonio , Martinucci Barbara
Published: November 2009

We consider a bilateral birth-death process having sigmoidal-type rates. A thorough discussion on its transient behaviour is given, which includes studying symmetry properties of the transition probabilities, finding conditions leading to their bimodality, determining mean and variance of the process, and analyzing absorption problems in the presence of 1 or 2 boundaries. In particular, thanks to the symmetry properties we obtain the avoiding transition probabilities in the presence of a pair of absorbing boundaries, expressed as a series.
Algorithmic Optimal Management of a Potable Water Distribution System: Application to the Primary Network of Bonaberi (Douala, Cameroon)
Authors: Sylvain Mbemmo Fotso Jacques , Thomas Tamo Tatietse , Simeu-Abazi Zineb
Published: November 2009

The optimal management of a potable water distribution system requires the control of the reference (standard) data, the control points, control of the drainage parameters (pressure, flow, etc.) and maintenance parameters. The control of the mentioned data defines the network learning process [1]. Besides classic IT functions of acquisition, storage and data processing, a geographical information system (GIS) can be used as the basis for an alarm system, allowing one to identify and to localize the presence of water leaks in the network [2]. In this article we propose an algorithm coupling the various drainage parameters for the management of the network. The algorithm leads to an optimal management of leaks. An application is in progress on the primary network in the region of Bonaberi in Douala, the largest city of Cameroon.
�n Narratiewe benadering tot die liturgie
Authors: Bosman Lourens , M�ller Julian C.
Published: November 2009

A narrative approach to liturgy The fact that current liturgical renewal is not based on sound theological reflection, is cause for concern. A narrative approach to liturgy is therefore proposed, which would allow a better connection between the cultural story on the one hand, and the story of the gospel and the liturgical tradition on the other. The article therefore explores possibilities for a narrative understanding of the liturgical context, and shows how a worship liturgy could be created like a collage instead of in the form of linear argumentation.�
Delay‐dependentH∞performance analysis and filtering for Markovian jump systems with interval time‐varying delays
Authors: Zhao Xudong , Zeng Qingshuang
Published: November 2009

This paper investigates the problems ofH∞disturbance attenuation andH∞filtering for Markovian jump systems with interval time‐varying delays. In terms of linear matrix inequalities, a less conservative delay‐range‐dependentH∞performance condition for Markovian jump systems is proposed by constructing a different Lyapunov–Krasovskii functional. The resulting criterion has advantages over some previous ones in that they involve fewer matrix variables, but has less conservatism. Based on this new condition, an improvedH∞filtering algorithm is developed. Numerical examples are provided to demonstrate the efficiency and reduced conservatism of the results in this paper. Copyright © 2009 John Wiley & Sons, Ltd.
The Effects of Casting Temperature on the Glass Formation of Zr‐Based Metallic Glasses
Authors: Mao Jie , Zhang Hai‐Feng , Fu Hua‐Meng , Wang Ai‐Min , Li Hong , Hu Zhuang‐Qi
Published: November 2009

The glass1‐forming ability of two alloys, Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8, prepared by arc‐melting a mixture of Zr, Cu, Al, Ni and Ag elements is studied as a function of casting temperature. Other processing parameters such as the alloy melt mass, and the vacuum and injection pressures during the copper‐mold‐casting process are kept constant so just the influence of the casting temperature is considered. The casting temperature determines the characteristics of the liquid melt and the cooling rate. The glass‐forming ability is discussed in terms of dissipation of pre‐exiting, metastable local‐ordering clusters that act as nucleation sites promoting crystallization, the cooling rate at high casting temperatures, and the presence of oxygen in the alloys, which is increased at high casting temperatures. It is found that the glass‐forming ranges of alloys shrink as the glass‐forming size approaches a critical value. The optimum temperatures are around 1450 K and 1550 K for Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8 alloys respectively. The alloys were studied by XRD, TEM, oxygen‐level determination, and DSC.
Three‐Dimensional Printing of Complex‐Shaped Alumina/Glass Composites
Authors: Zhang Wei , Melcher Reinhold , Travitzky Nahum , Bordia Rajendra Kumar , Greil Peter
Published: November 2009

Alumina/glass composites were fabricated by three‐dimensional printing (3DP™) and pressureless infiltration of lanthanum‐alumino‐silicate glass into sintered porous alumina preforms. The preforms were printed using an alumina/dextrin powder blend as a precursor material. They were sintered at 1600 °C for 2 h prior to glass infiltration at 1100 °C for 2 h. The influence of layer thickness and sample orientation within the building chamber of the 3D‐printer on microstructure, porosity, and mechanical properties of the preforms and final composites was investigated. The increase of the layer thickness from 90 to 150 µm resulted in an increase of the total porosity from ∼19 to ∼39 vol% and thus, in a decrease of the mechanical properties of the sintered preforms. Bending strength and elastic modulus of sintered preforms were found to attain significantly higher values for samples orientated along the Y‐axis of the 3D‐printer compared to those orientated along the X‐ or the Z‐axis, respectively. Fabricated Al2O3/glass composites exhibit improved fracture toughness, bending strength, Young's modulus, and Vickers hardness up to 3.6 MPa m1/2, 175 MPa, 228 GPa, and 12 GPa, respectively. Prototypes were fabricated on the basis of computer tomography data and computer aided design data to show geometric capability of the process.
3D Architecture and Load Partition in Eutectic Al‐Si Alloys
Authors: Requena Guillermo , Garcés Gerardo , Rodríguez Marcos , Pirling Thilo , Cloetens Peter
Published: November 2009

The changes of the three dimensional architecture of a eutectic AlSi12 alloy during heat treatment are revealed by means of synchrotron holotomography. The non‐destructive nature of the holotomography technique allows to analyze the same volumes in different thermal conditions. The results show a disintegration of the interconnected eutectic Si‐lamellae into isolated elongated particles. The load carrying capacity of both types of Si morphologies is studied by in situ neutron diffraction during compression tests. The experimental results are compared to those obtained using a micromechanical model developed for metal matrix composites based on a homogenization approach. The correlation between experiments and calculations shows that the interconnectivity of Si must be considered to account for the strength exhibited by the eutectic alloy. The present study bridges the gap between the already available two‐dimensional studies of architecture and properties of the binary AlSi12 alloy and new three‐dimensional studies of more complex systems based on this alloy.
Katalytische Funktionalisierung von Indolen in einer neuen Dimension
Authors: Bandini Marco , Eichholzer Astrid
Published: November 2009

Vor 140 Jahren schlug Adolf von Baeyer die Struktur für eine heteroaromatische Verbindung vor, die die organische und medizinische Chemie nachhaltig veränderte: Indol. Nach mehr als einem Jahrhundert beeinflussen Indol selbst, ebenso wie natürliche Indolderivate, weitgehend die Entwicklung in der Synthesechemie. Vor allem die allgegenwärtige Präsenz des Indolrings in pharmazeutischen und agrochemischen Verbindungen sowie seine Verwendung in der Materialchemie sind ausschlaggebend für das anhaltende Interesse an der Entwicklung von neuen milden und effizienten Synthesestrategien für funktionalisierte Indolderivate. Dieser Aufsatz fasst die Fortschritte hinsichtlich der selektiven katalytischen Funktionalisierung von Indolen (durch C‐C‐Kupplung) aus den vergangenen vier Jahre zusammen.
Von der Ostwald‐Reifung zur Homochiralität
Authors: Noorduin Wim L. , Vlieg Elias , Kellogg Richard M. , Kaptein Bernard
Published: November 2009

Vor einhundert Jahren erhielt Wilhelm Ostwald den Nobelpreis für Chemie. Obwohl Ostwald wenig mit dem Phänomen der Chiralität befasst war, gilt eine seiner Entdeckungen, die Ostwald‐Reifung, als wegbereitend für eine kürzlich eingeführte Methode, bei der durch zermahlungsinduzierten Abrieb racemische Konglomerate praktisch quantitativ in ein einzelnes Enantiomer überführt werden. Wir erläutern hier die von Ostwald eingeführten Konzepte und geben einen Überblick über den Stand der Technik bei zermahlungsinduzierten asymmetrischen Umwandlungen. Wir werden sehen, wie nahe schon Ostwald der Entdeckung dieser Technik gekommen war.
Catalytic Functionalization of Indoles in a New Dimension
Authors: Bandini Marco , Eichholzer Astrid
Published: November 2009

140 Years ago Adolf von Baeyer proposed the structure of a heteroaromatic compound which revolutionized organic and medical chemistry: indole. After more than a century, indole itself and the complexity of naturally occurring indole derivatives continue to inspire and influence developments in synthetic chemistry. In particular, the ubiquitous presence of indole rings in pharmaceuticals, agrochemicals, and functional materials are testament to the ever increasing interest in the design of mild and efficient synthetic routes to functionalized indole derivatives. This Review emphasizes the achievements in the selective catalytic functionalization of indoles (CC bond‐forming processes) over the last four years.
From Ostwald Ripening to Single Chirality
Authors: Noorduin Wim L. , Vlieg Elias , Kellogg Richard M. , Kaptein Bernard
Published: November 2009

A century ago Wilhelm Ostwald received the Nobel Prize for Chemistry. Although Ostwald was never significantly involved with the phenomenon of chirality, one of his discoveries, Ostwald ripening, is thought to be involved in a recently discovered method in which grinding‐induced attrition is used to transform racemic conglomerates virtually quantitatively into a single enantiomer. In this Minireview the basic concepts developed by Ostwald will be introduced, followed by a summary of the current status of grinding‐induced asymmetric transformations. We will see how close Ostwald himself came to discovering this technique.
A simple and reliable method to conduct and monitor expression cassette integration into the Escherichia coli chromosome
Authors: Albermann Christoph , Trachtmann Natalie , Sprenger Georg A.
Published: November 2009

We report a method for the integration of expression cassettes into the Escherichia coli chromosome using rare and dispensable sugar degradation gene loci as sites for integration. Clones carrying successfully recombined DNA fragments in the chromosome are easily screened using a solid differential medium containing the respective sugar compound. As an example for the heterologous expression of a complex natural product biosynthesis pathway, we show the stepwise chromosomal integration of the zeaxanthin biosynthesis pathway from Pantoea ananatis into E. coli.
Cyclostreptin and Microtubules: Is a Low‐Affinity Binding Site Required?
Authors: Prussia Andrew J. , Yang Yutao , Geballe Matthew T. , Snyder James P.
Published: November 2009

Cyclostreptin (CS) is a recently discovered natural product with cytotoxic activity caused by microtubule stabilization. It is the only known microtubule‐stabilizing agent (MSA) that covalently binds to tubulin. It also exhibits the fast‐binding kinetics seen for other MSAs. Through careful peptide digestion and mass spectrometry analysis, Buey et al. found that two amino acids are labeled by CS: Asn228, near the known taxane‐binding site, and Thr220, in the type I microtubule pore. This led Buey et al. to propose Thr220 resides at the site previously predicted to be a way station or low‐affinity site. By using molecular dynamics simulations and structural considerations of the microtubule pore and tubulin dimer, we conclude that postulation of a low‐affinity site is unnecessary to explain the available experimental data. An alternative explanation views the microtubule pore as a structural entity that presents a substantial kinetic barrier to ligand passage to the known taxane‐binding site—an entry point to the microtubule lumen that becomes completely blocked if cyclostreptin is bound at Thr220. Simulations of the free dimer also suggest a common mechanism of microtubule stabilization for taxane site MSAs through their conformational effect on the M‐loop. Such an effect explains the low tubulin polymerization caused by cyclostreptin in vitro despite its covalent attachment.
From Salts to Ionic Liquids by Systematic Structural Modifications: A Rational Approach Towards the Efficient Modular Synthesis of Enantiopure Imidazolium Salts
Authors: Ríos‐Lombardía Nicolás , Busto Eduardo , Gotor‐Fernández Vicente , Gotor Vicente , Porcar Raúl , García‐Verdugo Eduardo , Luis Santiago V. , Alfonso Ignacio , García‐Granda Santiago , Menéndez‐Velázquez Amador
Published: November 2009

This paper reports a simple and robust modular synthetic strategy that leads to a large variety of configurationally and structurally diverse imidazole‐based chiral ionic liquids (CILs) by lipase‐catalyzed resolution. The intimate microscopic interactions of the supramolecular ionic network of these imidazolium chiral salts at the molecular level are investigated both spectroscopically (NMR, FT‐IR‐ATR) and theoretically, and a topological analysis of the experimental electron densities obtained by X‐ray diffraction of single crystals is performed. Our results support the key role played by the relative configuration of the ‐OR group on the hydrogen‐bonding pattern and its strong influence on the final physical properties of the imidazolium salt. We also obtained a reasonable correlation between the observed melting point and the non‐covalent interactions. The spectroscopic data and the topological analysis reflect the key role played by hydrogen bonds between the OH and imidazolium C2H groups in both cation–anion and cation–cation interactions, with the presence of an OH group leading to an additional inter‐cation interaction. This interaction significantly affects the properties of stereoisomeric salts. Even more interestingly, we also studied the effect of the chirality by comparing enantiopure CILs with their racemic mixtures and found that, with the exception oftrans‐Cy6‐OH‐Im‐Bn‐Br, the melting points of the racemic mixtures are higher than those of the corresponding enantiomerically pure forms. For stereoisomeric examples, we have successfully explained the differences in melting temperatures in light of the corresponding structural data. Chirality should therefore be taken into account as a highly attractive design vector in the preparation of ILs with specifically desired properties.
Lanthanide versus Actinide Reactivity in the Formation of Sterically Crowded [(C5Me5)3MLn] Nitrile and Isocyanide Complexes
Authors: Evans William J. , Mueller Thomas J. , Ziller Joseph W.
Published: November 2009

The limits of steric crowding in organometallic metallocene complexes have been examined by studying the synthesis of [(C5Me5)3MLn] complexes as a function of metal in which L=Me3CCN, Me3CNC, and Me3SiCN. The bis(tert‐butyl nitrile) complexes [(C5Me5)3Ln(NCCMe3)2] (Ln=La, 1; Ce, 2; Pr, 3) can be isolated with the largest lanthanide metal ions, La3+, Ce3+, and Pr3+. The Pr3+ ion also forms an isolable mono‐nitrile complex, [(C5Me5)3Pr(NCCMe3)] (4), whereas for Nd3+ only the mono‐adduct [(C5Me5)3Nd(NCCMe3)] (5) was observed. With smaller metal ions, Sm3+ and Y3+, insertion of Me3CCN into the MC(C5Me5) bond was observed to form the cyclopentadiene‐substituted ketimide complexes [(C5Me5)2Ln{NC(C5Me5)(CMe3)}(NCCMe3)] (Ln=Sm, 6; Y, 7). With tert‐butyl isocyanide ligands, a bis‐isocyanide product can be isolated with lanthanum, [(C5Me5)3La(CNCMe3)2] (8), and a mono‐isocyanide product with neodymium, [(C5Me5)3Nd(CNCMe3)] (9). Silicon–carbon bond cleavage was observed in reactions between [(C5Me5)3Ln] complexes and trimethylsilyl cyanide, Me3SiCN, to produce the trimeric cyanide complexes [{(C5Me5)2Ln(μ‐CN)(NCSiMe3)}3] (Ln=La, 10; Pr, 11). With uranium, a mono‐nitrile reaction product, [(C5Me5)3U(NCCMe3)] (12), which is analogous to 5, was obtained from the reaction between [(C5Me5)3U] and Me3CCN, but [(C5Me5)3U] reacts with Me3CNC through CN bond cleavage to form a trimeric cyanide complex, [{(C5Me5)2U(μ‐CN)(CNCMe3)}3] (13).
Rigid‐Strut‐Containing Crown Ethers and [2]Catenanes for Incorporation into Metal–Organic Frameworks
Authors: Zhao Yan‐Li , Liu Lihua , Zhang Wenyu , Sue Chi‐Hau , Li Qiaowei , Miljanić Ognjen Š. , Yaghi Omar M. , Stoddart J. Fraser
Published: November 2009

To introduce crown ethers into the struts of metal–organic frameworks (MOFs), general approaches have been developed for the syntheses of dicarboxylic acid dibenzo[30]crown‐10 (DB30C10DA), dicarboxylic acid di‐2,3‐naphtho[30]crown‐10 (DN30C10DA), dicarboxylic acid bisparaphenylene[34]crown‐10 (BPP34C10DA), and dicarboxylic acid 1,5‐naphthoparaphenylene[36]crown‐10 (NPP36C10DA). These novel crown ethers not only retain the characteristics of their parent crown ethers since they can 1) bind cationic guests and 2) serve as templates for making mechanically interlocked molecules (MIMs), such as catenanes and rotaxanes, but they also present coordination sites to connect with secondary building units (SBUs) in MOFs. The binding behavior of BPP34C10DA with 1,1′‐dimethyl‐4,4′‐bipyridinium bis(hexafluorophosphate) (DMBP⋅2 PF6) has been investigated by means of UV/Vis, fluorescence, and NMR spectroscopic techniques. The crystal superstructure of the complex DMBP⋅2 PF6⊂ BPP34C10DA was determined by X‐ray crystallography. The NPP36C10DA‐based [2]catenane (H2NPP36C10DC‐CAT⋅4 PF6) and the BPP34C10DA‐based [2]catenane (H2BPP34C10DC‐CAT⋅4 PF6) were prepared in DMF at room temperature by the template‐directed clipping reactions of the planarly chiral NPP36C10DA and BPP34C10DA with 1,1′‐[1,4‐phenylenebis(methylene)]di‐4,4′‐bipyridin‐1‐ium bis(hexafluorophosphate) and 1,4‐bis(bromomethyl)benzene, respectively. The crystal structure of the dimethyl ester (BPP34C10DE‐CAT⋅4 PF6) of the [2]catenane H2BPP34C10DC‐CAT⋅4 PF6 was investigated by X‐ray crystallography, which revealed racemic R and S isomers with planar chirality present in the crystal in a 1:1 ratio. These crown ether based struts serve as excellent organic ligands to bind with transition metal ions in the construction of MOFs: the crown ethers BPP34C10DA and NPP36C10DA in the presence of Zn(NO3)2⋅4 H2O afforded the MOF‐1001 and MOF‐1002 frameworks, respectively. The crystal structures of MOF‐1001 and MOF‐1002 are both cubic and display Fm$\bar 3$m symmetry. The unit cell parameter of the metal–organic frameworks is a=52.9345 Å. Since such MOFs, containing electron‐donating crown ethers are capable of docking incoming electron‐accepting substrates in a stereoelectronically controlled fashion, the present work opens a new access to the preparation and application of MOFs.
Effect of Guest–Host Hydrogen Bonding on the Structures and Properties of Clathrate Hydrates
Authors: Alavi Saman , Udachin Konstantin , Ripmeester John A.
Published: November 2009

To provide improved understanding of guest–host interactions in clathrate hydrates, we present some correlations between guest chemical structures and observations on the corresponding hydrate properties. From these correlations it is clear that directional interactions such as hydrogen bonding between guest and host are likely, although these have been ignored to greater or lesser degrees because there has been no direct structural evidence for such interactions. For the first time, single‐crystal X‐ray crystallography has been used to detect guest–host hydrogen bonding in structure II (sII) and structure H (sH) clathrate hydrates. The clathrates studied are the tert‐butylamine (tBA) sII clathrate with H2S/Xe help gases and the pinacolone + H2S binary sH clathrate. X‐ray structural analysis shows that the tBA nitrogen atom lies at a distance of 2.64 Å from the closest clathrate hydrate water oxygen atom, whereas the pinacolone oxygen atom is determined to lie at a distance of 2.96 Å from the closest water oxygen atom. These distances are compatible with guest–water hydrogen bonding. Results of molecular dynamics simulations on these systems are consistent with the X‐ray crystallographic observations. The tBA guest shows long‐lived guest–host hydrogen bonding with the nitrogen atom tethered to a water HO group that rotates towards the cage center to face the guest nitrogen atom. Pinacolone forms thermally activated guest–host hydrogen bonds with the lattice water molecules; these have been studied for temperatures in the range of 100–250 K. Guest–host hydrogen bonding leads to the formation of Bjerrum L‐defects in the clathrate water lattice between two adjacent water molecules, and these are implicated in the stabilities of the hydrate lattices, the water dynamics, and the dielectric properties. The reported stable hydrogen‐bonded guest–host structures also tend to blur the longstanding distinction between true clathrates and semiclathrates.
BCN: A Graphene Analogue with Remarkable Adsorptive Properties
Authors: Raidongia Kalyan , Nag Angshuman , Hembram K. P. S. S. , Waghmare Umesh V. , Datta Ranjan , Rao C. N. R.
Published: November 2009

A new analogue of graphene containing boron, carbon and nitrogen (BCN) has been obtained by the reaction of high‐surface‐area activated charcoal with a mixture of boric acid and urea at 900 °C. X‐ray photoelectron spectroscopy and electron energy‐loss spectroscopy reveal the composition to be close to BCN. The X‐ray diffraction pattern, high‐resolution electron microscopy images and Raman spectrum indicate the presence of graphite‐type layers with low sheet‐to‐sheet registry. Atomic force microscopy reveals the sample to consist of two to three layers of BCN, as in a few‐layer graphene. BCN exhibits more electrical resistivity than graphene, but weaker magnetic features. BCN exhibits a surface area of 2911 m2 g−1, which is the highest value known for a BxCyNz composition. It exhibits high propensity for adsorbing CO2 (≈100 wt %) at 195 K and a hydrogen uptake of 2.6 wt % at 77 K. A first‐principles pseudopotential‐based DFT study shows the stable structure to consist of BN3 and NB3 motifs. The calculations also suggest the strongest CO2 adsorption to occur with a binding energy of 3.7 kJ mol−1 compared with 2.0 kJ mol−1 on graphene.
A Facile Circular Dichroism Protocol for Rapid Determination of Enantiomeric Excess and Concentration of Chiral Primary Amines
Authors: Nieto Sonia , Dragna Justin M. , Anslyn Eric V.
Published: November 2009

A protocol for the rapid determination of the absolute configuration and enantiomeric excess (ee) of α‐chiral primary amines with potential applications in asymmetric reaction discovery has been developed. The protocol requires derivatization of α‐chiral primary amines through condensation with pyridine carboxaldehyde to quantitatively yield the corresponding imine. The CuI complex with 2,2′‐bis (diphenylphosphino)‐1,1′‐dinaphthyl (BINAPCuI) with the imine yields a metal‐to‐ligand charge‐transfer (MLCT) band in the visible region of the circular dichroism (CD) spectrum upon binding. Diastereomeric host–guest complexes give CD signals of the same signs but different amplitudes, allowing for differentiation of enantiomers. Processing the primary optical data from the CD spectrum with linear discriminant analysis (LDA) allows for the determination of the absolute configuration and identification of the amines, and processing with a supervised multilayer perceptron artificial neural network (MLP‐ANN) allows for the simultaneous determination of the ee and concentration. The primary optical data necessary to determine the ee of unknown samples is obtained in two minutes per sample. To demonstrate the utility of the protocol in asymmetric reaction discovery, the ee values and concentrations for an asymmetric metal‐catalyzed reaction are determined. The potential of the application of this protocol in high‐throughput screening (HTS) of ee is discussed.
B‐cell fate decisions following influenza virus infection
Authors: Rothaeusler Kristina , Baumgarth Nicole
Published: November 2009

Rapidly induced, specific Ab generated in extrafollicular foci are important components of early immune protection to influenza virus. The signal(s) that prompt B cells to participate in extrafollicular rather than germinal center responses are incompletely understood. To study the regulation of early B‐cell differentiation events following influenza infection, we exploited earlier findings of a strong contribution of C12 idiotype‐expressing B cells to the primary HA‐specific response against influenza A/PR/8/34. Using an idiotype‐specific mAb to C12 and labeled HA, in conjunction with multicolor flow cytometry, we followed the fate of C12Id‐expressing influenza HA‐specific B cells in WT BALB/c mice, requiring neither genetic manipulation nor adoptive cell transfer. Our studies demonstrate that HA‐specific C12Id+ B cells are phenotypically indistinguishable from follicular B cells. While they induced both extrafollicular and germinal center responses, extrafollicular responses were strongly predominant. Provision of increased HA‐specific T‐cell help increased the magnitude of the extrafollicular response, but did not shift the C12Id+ response toward germinal center formation. Collectively the data are consistent with the hypothesis that B‐cell fate determination following activation is a stochastic process in which infection‐induced innate signals might drive the preferential expansion of the early extrafollicular response.