bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractAlthough 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

AbstractThe 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

AbstractNitrogen (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

BACKGROUNDUse 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.METHODSParticipants 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.RESULTSCompared 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.CONCLUSIONSCigarette 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

BACKGROUNDA 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.METHODSEleven 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.RESULTSUsing 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.CONCLUSIONSThe 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

AbstractPentenary 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

BackgroundParadoxical 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.MethodsSide‐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.ResultResults 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.ConclusionsTo 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.
Adaptive modulation and decision feedback equalization for frequency‐selective MIMO channels
Authors: Ammari Mohamed Lassaad , Zaouali Kalthoum , Fortier Paul 
Published: April 2013

SUMMARYIn this paper, an adaptive modulation scheme for the multiple‐input multiple‐output (MIMO) frequency‐selective channels is investigated. We consider a scenario with precoded block‐based transceivers over spatially correlated Rayleigh multipath MIMO channels. To eliminate the inter‐block interference, the zero‐padding is used. The receiver is equipped with a MIMO minimum‐mean‐squared‐error decision feedback equalizer. The precoder aims to force each subchannel to have an identical signal‐to‐interference‐plus‐noise ratio (SINR). To adjust the constellation size, the unbiased mean square error at the equalizer output is sent back to the transmitter. To simplify our analysis, the feedback channel is considered as instantaneous and error free. We first derive the probability density function of the overall SINR for flat fading and frequency‐selective channels. On the basis of the probability density function of the upper bound of the SINR, we evaluate the system performance. We present accurate closed‐form expressions of the average spectral efficiency, the average bit error rate and the outage probability. The derived expressions are compared with Monte Carlo simulation results. Furthermore, we analyze the effect of the channel spatial correlation. Copyright © 2013 John Wiley & Sons, Ltd.
Control Structure Design for CO2‐Absorption Processes with Large Operating Ranges
Authors: Schach Marc‐Oliver , Schneider Rüdiger , Schramm Henning , Repke Jens‐Uwe 
Published: April 2013

AbstractCoal‐fired power plants are operated flexibly over a large operating range, with variations in flue‐gas mass flow rate and composition. Postcombustion absorption processes are used to separate the CO2 from the flue gas at every operating point in the most economical way. Maintaining an economically feasible operation is the objective of the control structure. In this work the control structures were designed using a self‐optimizing control procedure for two process configurations. The control structures allow for an economic operation with a power‐plant load in the range of 40–100 %. The loss of the designed feedback‐control structures in comparison to an optimized control at every operating point was between 0.57 and 2.64 % in terms of cost of CO2 avoided.
Two New Sesquiterpenes from the Roots of Valeriana faurieiBriq.
Authors: Liu Xue‐Gui , Zhang Weng‐Chao , Gao Pin‐Yi , Wang Guo‐Sheng , Li Ling‐Zhi , Song Shao‐Jiang , Zhang Xiang , Yao Xin‐Sheng , Liu Ke , Zhang Zhen‐Xue 
Published: April 2013

AbstractA phytochemical investigation of the MeOH extract of Valeriana fauriei Briq. roots resulted in the isolation of two new sesquiterpenes, isovalerianin A (=(1β,4Z,6β,8α)‐8‐(acetyloxy)‐1,10‐dihydroxy‐6,11‐cyclogermacr‐4‐en‐15‐al=rel‐(1R,2Z,6S,7R,9R,10S)‐9‐(acetyloxy)‐6,7‐dihydroxy‐7,11,11‐trimethylbicyclo[8.1.0]undec‐2‐ene‐3‐carboxaldehyde; 1) and valerianin C (=(2α,3α,6α,8α)‐3‐(acetyloxy)‐2,4,8‐trihydroxyguai‐1(10)‐ene‐12,6‐lactone=rel‐(3R,3aS,4R,7S,8S,9R,9aR,9bR)‐8‐(acetyloxy)‐3a,4,5,7,8,9,9a,9b‐ octahydro‐4,7,9‐trihydroxy‐3,6,9‐trimethylazuleno[4,5‐b]furan‐2(3H)‐one; 2), together with six known compounds, i.e., camphor, methyl 4‐hydroxybenzoate, 2‐methoxybenzoic acid, benzoic acid, quercetin, and kaempferol. The structures of the compounds were established by detailed spectral analysis and comparison with previously reported data.
Three New Sesquiterpenes from Laggera pterodonta
Authors: Zhang Zhi‐Jun , He Juan , Li Yan , Wu Xing‐De , Gao Xiu , Peng Li‐Yan , Cheng Xiao , Li Rong‐Tao , Zhao Qin‐Shi 
Published: April 2013

AbstractA new eremophilane sesquiterpene, (2β)‐2‐deoxo‐2‐methoxytessaric acid (1), and two new eudesmane sesquiterpenes, (3β,10α)‐3‐methoxyleudesma‐4,11(13)‐dien‐12‐oic acid (2) and (3α,4β,8α)‐4‐(acetyloxy)‐3‐(2,3‐dihydroxy)‐2‐methyl‐1‐oxobutoxy‐8‐hydroxyeudesm‐7(11)‐eno‐12,8‐lactone (3), along with the ten known compounds 4–13 were isolated from the aerial parts of Laggera pterodonta. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR data.
A Simple Synthesis of 2‐{(Arylmethylidene)hydrazinylidene]‐3‐hydroxy‐4H‐furo[3,2‐c]pyran‐4(3H)‐ones
Authors: Adib Mehdi , Ansari Samira , Zhu Long‐Guan , Rahimi‐Nasrabadi Mehdi 
Published: April 2013

AbstractA simple synthesis of 2‐hydrazinylidene‐3‐hydroxy‐4H‐furo[3,2‐c]pyran‐4‐ones is described. A mixture of (isocyanoimino)(triphenyl)phosphorane, an aromatic aldehyde, and dehydroacetic acid (=3‐acetyl‐2‐hydroxy‐6‐methyl‐4H‐pyran‐4‐one) undergo a 1 : 1 : 1 addition reaction under mild conditions to afford the title compounds in excellent yields.
A Convenient Synthesis of 2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]‐, ‐[2,3‐c]‐, or ‐[3,2‐c]pyridin‐4‐ones by the Reaction of the Corresponding 1‐(Chloropyridinyl)alk‐2‐en‐1‐ones with NaSH
Authors: Kobayashi Kazuhiro , Imaoka Ayumi 
Published: April 2013

Abstract2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]pyridin‐4‐ones 4 were prepared by a three‐step sequence from commercially available 2‐chloropyridine (1). Thus, successive treatment of 1 with iPr2NLi (LDA) and α,β‐unsaturated aldehydes gave 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ols 2, which were oxidized with MnO2 to 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ones 3. The reactions of 3 with NaSH⋅n H2O proceeded smoothly at 0° in DMF to provide the desired thiopyranopyridinones. Similarly, 2,3‐dihydro‐4H‐thiopyrano[2,3‐c]pyridin‐4‐ones 8 and 2,3‐dihydro‐4H‐thiopyrano[3,2‐c]pyridin‐4‐ones 12 were obtained starting from 3‐chloropyridine (5) and 4‐chloropyridine (9), respectively.
Analysis of acetic acid, furfural and 5‐hydroxymethylfurfural affecting 2, 3‐butanediol production using Klebsiella oxytoca
Authors: Wu Jing , Cheng Ke‐Ke , Wang Gen‐Yu , Li Wen‐Ying , Feng Jie , Zhang Jian‐An 
Published: April 2013

AbstractBACKGROUNDThe effect of the combination of acetic acid, furfural and 5‐hydroxymethylfurfural on 2, 3‐butanediol fermentation of Klebsiella oxytoca was studied by statistical analysis. The compounds were selected taking into account their concentration in the hydrolysate from the acid pretreatment of biomass and their toxicity. A central composite design was used to investigate the influences of these compounds on 2, 3‐butanediol yield and biomass formation.RESULTSTwo models were developed to describe the effect of the combination of acetic acid, furfural and 5‐hydroxymethylfurfural on biomass and product yield in 2, 3‐butanediol fermentation. The proposed model is suited to fit experimental data and to simulate cell growth and 2, 3‐butanediol yield, which was confirmed by 2, 3‐butanediol production using real hydrolysate as substrate.CONCLUSIONBiomass yield was affected mainly by the ‘main effects’ of the tested compounds and no interaction relationship among acetic acid, furfural and HMF was found. 2, 3‐butanediol yield was more sensitive to acetic acid concentration. Selective removal of furfural in hydrolysate would contribute to the simultaneous improvement of 2, 3‐butanediol yield and cell growth. © 2013 Society of Chemical Industry
Diffusion tensor imaging (DTI) of the normal human uterus in vivo at 3 tesla: Comparison of DTI parameters in the different uterine layers
Authors: Fujimoto Koji , Kido Aki , Okada Tomohisa , Uchikoshi Masato , Togashi Kaori 
Published: April 2013

PurposeTo investigate the differences in the fiber architecture and related diffusion tensor imaging (DTI) parameters among different uterine layers of the normal human uterus in vivo at 3 Tesla (T).Materials and MethodsDTI of the uterus was performed for nine healthy women of reproductive age on a 3T scanner. A volume of interest (VOI) was drawn for the outer myometrium (OM), junctional zone (JZ), and endometrium (EM). Apparent diffusion coefficient (ADC), fractional anisotropy (FA), and maximum fiber length were compared using paired Student's t‐tests. Fibers were classified into four groups and were visually evaluated.ResultsADC (×10−3 mm2/s) was highest for OM (1.12), followed by EM (0.97) and JZ (0.83) (OM versus JZ, P < 0.0001; JZ versus EM, P = 0.0001; OM versus EM, P = 0.0057). FA was highest for JZ (0.297), followed by OM (0.257) and EM (0.186) (OM versus JZ, P = 0.0002; JZ versus EM, P < 0.0001; OM versus EM, P < 0.0001). Fibers were longest in OM (42.0 mm), followed by JZ (34.2 mm) and EM (20.0 mm). Circularly oriented fibers were observed in 69% in OM and in 70% in JZ.ConclusionDTI of the uterus in vivo revealed layer‐wise differences in the microstructure of the uterus. J. Magn. Reson. Imaging 2013;38:1494–1500. © 2013 Wiley Periodicals, Inc.
Traditional foods from the Black Sea region as a potential source of minerals
Authors: Albuquerque Tânia G , Costa Helena S , Sanches‐Silva Ana , Santos Mariana , Trichopoulou Antonia , D'Antuono Filippo , Alexieva Iordanka , Boyko Nadiya , Costea Carmen , Fedosova Katerina , Karpenko Dmitry , Kilasonia Zaza , Koçaoglu Bike , Finglas Paul 
Published: April 2013

AbstractBACKGROUNDIn the past few years, minerals have assumed great importance in public health. As a consequence, considerable research has been carried out to better understand their physiological role and the health consequences of mineral‐deficient diets, to establish criteria for defining the degree of public health severity of malnutrition, and to develop prevention and control strategies. In most countries, there is limited information on the mineral content of traditional foods, and consequently it is very difficult to estimate mineral intake across these countries.RESULTSTen minerals were quantified in 33 traditional foods from Black Sea area countries. Our results indicate a considerable variability among the analysed traditional foods; nevertheless, the most abundant components were sodium (ranging from 40.0 to 619 mg 100 g−1, for kvass southern and herbal dish, respectively), potassium (varied between 45.5 mg 100 g−1 for millet ale and 938 mg 100 g−1 for roasted sunflower seeds), and phosphorus (22.2 mg 100 g−1 and 681 mg 100 g−1 for sauerkraut and roasted sunflower seeds, respectively).CONCLUSIONThis is the first study that provides validated data on the mineral content for 33 traditional foods from Black Sea area countries, which is important in order to elucidate their role in the dietary pattern of populations and to preserve and promote these foods. © 2013 Society of Chemical Industry
Phase of nasal cycle during sleep tends to be associated with sleep stage
Authors: Kimura Akihiro , Chiba Shintaro , Capasso Robson , Yagi Tomoko , Ando Yuji , Watanabe Subaru , Moriyama Hiroshi 
Published: April 2013

Background and ObjectivesThe phenomena of periodic cycles of vascular engorgement on the nasal cavity mucosa that alternate between right and left sides are termed the “nasal cycle.” The physiologic mechanisms underlying this cycle have not been entirely clarified, even more so during sleep. In this study, we measured the periodic patterns of the normal nasal cycle, not only during wakefulness but also during sleep.Study Design: Case Series MethodsOur team utilized a method for functional rhinologic assessment, the portable rhinoflowmeter (Rhinocycle, Rhinometrics, Lynge, Denmark), measuring airflow independently through each nostril during 24 hours on 20 healthy subjects aged 20 to 56 years, and without any nasal pathology or diagnosed medical, psychiatric, or sleep disorders. In addition, a nocturnal polysomnogram was simultaneously performed during sleep.ResultsNineteen of 20 subjects showed a detectable nasal cycle, and 16 of 19 subjects presented a change of the cyclic phase during sleep. The mean nasal cycle duration was 234.2±282.4 minutes (median, 164.1 minutes), although variation was considerable. The mean cycle duration time during sleep was significantly longer than that in wakefulness (P <0.005). The reversal of cyclic phase during sleep tended to be associated with REM sleep (68.8%) and postural changes (18.8%). It never occurred in slow‐wave sleep.ConclusionsNasal cycle duration during sleep is longer than in wakefulness. Changes in laterality of nasal cycle frequently coincide with switches in posture, tend to occur in REM sleep, never occur in slow‐wave sleep, and may be absent in subjects with severe nasal septal deviations.Level of Evidence4. Laryngoscope, 123:2050–2055, 2013