bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Redox Activity of Rigid Ferrocenyl Dendrimers, and Isolation of Robust Ferricinium and Class‐II Mixed‐Valence Dendrimers
Authors: Diallo Abdou K. , Ruiz Jaime , Astruc Didier 
Published: May 2013

AbstractThe coupling reactions of ethynylferrocene with trihalogenoarenes do not lead to ethynylferrocenyl arenes that are soluble enough to form the basis of a suitable construction of stiff ferrocenylethynyl arene‐cored dendrimers, which explains the previous lack of reports on stiff ferrocenyl dendrimers. However, rigid ferrocenyl‐terminated dendrimers have been synthesized from 1,3,5‐tribromo‐ and triiodobenzene through Sonogashira and Negishi reactions with 1,2,3,4,5‐pentamethyl‐1′‐ethylnylferrocene (1 a), according to 1→2 connectivity. With compound 1 a, the construction of a soluble dendrimer (10 a) that contained 12 ethynylpentamethylferrocenyl termini was achieved. Stiff dendrimer 10 a shows a single, reversible cyclic voltammetry (CV) wave (with adsorption), which disfavors the hopping heterogeneous electron‐transfer mechanism that is postulated for redox‐terminated dendrimers that contain flexible tethers. The selectivity of these Sonogashira reactions allows the synthesis of an arene‐cored dendron (2 c) that contains both ethynylferrocenyl and 1,2,3,4,5‐pentamethyl‐ferrocenylethynyl redox groups, thus leading to the construction of a dendrimer (7 c) that contains both types of differently substituted ferrocenyl groups with two well‐separated reversible CV waves. Upon selective oxidation, this mixed dendrimer (7 c) leads to a class‐II mixed‐valence dendrimer, 7 c[PF6]3, as shown by Mössbauer spectroscopy, whereas oxidation of the related fully pentamethylferrocenylated dendrimer (7 a) leads to the all‐ferricinium dendrimer, 7 a[PF6]6.
Theoretical Study on the Cyclization Mechanism of Dipeptides
Authors: Xia Ping , Wang Chen , Qi Chenze 
Published: May 2013

AbstractCyclization is an important chemical reaction for the dipeptides containing N‐alkyl groups. The cyclization mechanism has been examined by theoretical calculations. Our calculation results indicate that the most favorable mechanism is the piperidine‐catalyzed stepwise mechanism, in which piperidine acts as a proton shuttle. The attack of the N‐terminal amino nitrogen at the C‐terminal carbonyl carbon along with the proton transfer is the rate‐limiting step. The effect of the alkyl substituent on the amide N on the cyclization reaction was then examined. Finally, the influence of the solvation effect, electronic effect and steric effect on the cyclization was investigated. It is found that all of these effects contribute to the cyclization.
Transition‐Metal‐Free TEMPO Catalyzed Aerobic Oxidation of Alcohols to Carbonyls Using an Efficient Br2 Equivalent under Mild Conditions
Authors: Zhang Jie , Jiang Zengqiang , Zhao Dan , He Guozhen , Zhou Shuangli , Han Shiqing 
Published: May 2013

AbstractAn effective transition‐metal‐free catalytic system is developed for aerobic oxidations of alcohols. Using catalytic amount of bromide‐bromate coupling, H2SO4, and NaNO2, together with 2,2,6,6‐tetramethylpiperidine N‐oxyl radical (TEMPO) in the presence of air, various alcohols could be converted into the corresponding aldehydes or ketones in good to excellent isolated yields under mild conditions.
Synthesis and Antitumor Activity Evaluation of γ‐Monofluorinated and γ,γ‐Difluorinated Goniothalamin Analogues
Authors: Yang Yi , Yang Zhenjun , Cheng Chunru , Qing Fengling 
Published: May 2013

AbstractA series of novel γ,γ‐difluorinated Goniothalamin analogues 4a–4i and 6a–6i were synthesized. The key steps included the construction of C‐5 stereocenter adjacent to gem‐difluoromethylene group by way of lipase AK catalyzed kinetic resolution, the introduction of aryl group via Stille coupling, and lactonization by 1,5‐oxidative cyclization. These γ,γ‐difluorinated Goniothalamin analogues 4a–4i and their enantiomers 6a–6i, together with several corresponding γ‐monofluorinated Goniothalamin analogues were biologically evaluated against four different cancer cell lines. Compound 7h showed a nearly equivalent potency as the parent (R)‐Goniothalamin in the micromolar range. The different fluorine effects between fluoromethylene and gem‐difluoromethylene on antitumor activity were discussed through the analysis of bioassay data.
Non‐covalent Sugar Modification and Self‐assembly of Fluorous Gold Nanoparticles Driven by Fluorous Interaction
Authors: Chen Zhifang , Chen Guosong 
Published: May 2013

AbstractFluorous gold nanoparticle (Fluo‐NP), i.e. gold nanoparticle covered by fluorous ponytail (C8F17‐) was prepared and found to self‐assemble into supra‐structures covered by carbohydrates (named supraF‐NP), due to the strong fluorous interaction. More importantly, the re‐dispersed supraF‐NP (diameter around 200 nm) in water provided an alternative strategy to detect carbohydrate‐protein interaction in solution by naked eye.
Preparation of Tris(2‐aminoethyl)amine‐Cross‐Linked Cyclodextrin‐Based Porous Nanospheres and Their Application as Drug Delivery Systems
Authors: Wang Youqing , Zhao Yanchao , Han Baohang 
Published: May 2013

AbstractCyclodextrins (CDs) show functionality, biocompatibility, and host‐guest inclusion capacity with a variety of molecules. These unique properties offer great potential for the exploitation of CDs as drug delivery systems. An easy, green, and effective synthetic approach was described to develop CD‐based porous nanospheres (CDPNSs) with a size distribution from 100 to 400 nm. A new cross‐linker tris(2‐aminoethyl)amine was used to cross‐link modified β‐CD at room temperature. The resulting CD‐based polymers (CDPs) were reshaped from a random morphology into a spherical shape during a dialysis process, and CDPNSs were obtained. The morphologies of CDPs and CDPNSs were observed with scanning electron microscopy. The average diameter and the size distribution of CDPNSs were determined by dynamic light scattering. The structures of the resulting products were characterized by using Fourier transform infrared spectroscopy, 1H NMR spectroscopy, solid‐state 13C CP/MAS NMR spectroscopy, and X‐ray diffraction. Furthermore, a study was conducted on drug loading and in vitro release behavior of CDPNSs, which was monitored by ultraviolet spectroscopy. The prepared CDPNSs show the potential as drug delivery systems.
Pathologic and gene expression features of metastatic melanomas to the brain
Authors: Hamilton Ronald , Krauze Michal , Romkes Marjorie , Omolo Bernard , Konstantinopoulos Panagiotis , Reinhart Todd , Harasymczuk Malgorzata , Wang YangYang , Lin Yan , Ferrone Soldano , Whiteside Theresa , Bortoluzzi Stephanie , Werley Jonette , Nukui Tomoko , Fallert‐Junecko Beth , Kondziolka Douglas , Ibrahim Joseph , Becker Dorothea , Kirkwood John , Moschos Stergios 
Published: May 2013

BACKGROUNDThe prognosis of metastatic melanomas to the brain (MBM) is variable with prolonged survival in a subset. It is unclear whether MBM differ from extracranial metastases (EcM) and primary melanomas (PrM).METHODSTo study the biology of MBM, histopathologic analysis of tumor blocks from patients' craniotomy samples and whole‐genome expression profiling (WGEP) with confirmatory immunohistochemistry were performed.RESULTSHigh mononuclear infiltrate and low intratumoral hemorrhage were associated with prolonged overall survival (OS). Pathway analysis of WGEP data from 29 such craniotomy tumor blocks demonstrated that several immune‐related BioCarta gene sets were associated with prolonged OS. WGEP analysis of MBM in comparison with same‐patient EcM and PrM showed that MBM and EcM were similar, but both differ significantly from PrM. Immunohistochemical analysis revealed that peritumoral CD3+ and CD8+ cells were associated with prolonged OS.CONCLUSIONSMBMs are more similar to EcM compared with PrM. Immune infiltrate is a favorable prognostic factor for MBM. Cancer 2013;119:2737–2746. © 2013 American Cancer Society.
Clinical Psychologists' Views of Intensive Interaction as an Intervention in Learning Disability Services
Authors: Berry Ruth , Firth Graham , Leeming Catherine , Sharma Vishal 
Published: May 2013

Intensive Interaction was initially developed in the 1980s as an educational approach for developing social communication and engagement with people with severe or profound intellectual disabilities and/or autism. Intensive Interaction has subsequently been adopted by a range of practitioners and professionals working in learning disability services and has a broad multi‐disciplinary acceptance, being recommended in a number of UK governmental guidance documents. Despite this, there has been limited work on developing a deeper psychological understanding of the approach. This study utilises a qualitative description/thematic analysis approach to explore how clinical psychologists conceptualise the approach with regard to currently accepted psychological theories, as well as looking at other factors that influence their adoption and advocacy. The sample deliberately consisted of eight NHS (National Health Service) clinical psychologists known to be using or advocating the use of Intensive Interaction with people with a learning disability.The results of this study indicate that although the participants referred to some theories that might explain the beneficial outcomes of Intensive Interaction, these theories were rarely explicitly or clearly referenced, resulting in the authors having to attribute specific theoretical positions on the basis of inductive analysis of the participants' responses. Moreover, the participants provided varying views on how Intensive Interaction might be conceptualised, highlighting the lack of a generally accepted, psychologically framed definition of the approach. In conclusion, it was felt that further research is required to develop a specifically psychological understanding of Intensive Interaction alongside the formation of a Special Interest Group, which might have this task as one of its aims. Copyright © 2013 John Wiley & Sons, Ltd.Key Practitioner MessagesThere appeared to be a limited recognition amongst the participants of the specific psychological theories that can be seen to explain the beneficial outcomes of Intensive Interaction.The participants were found to differ in how they explained the approach and typically used everyday ‘non‐psychological’ language or individual concepts/terms rather than clearly or extensively referencing particular theoretical models.The participants appeared to differ in the range of clients who they thought might benefit from Intensive Interaction.An Intensive Interaction Special Interest Group, which includes clinical psychologists, should be set up to instigate psychologically informed theory development and research with the broader aims of fostering greater understanding and adoption of Intensive Interaction within services for people with severe or profound intellectual disabilities and/or autism.
Repetitive auditory stimulation at a critical prenatal period modulates the postnatal functional development of the auditory as well as visual system in chicks (Gallus domesticus)
Authors: Roy Saborni , Nag Tapas C. , Upadhyay Ashish Datt , Mathur Rashmi , Jain Suman 
Published: May 2013

ABSTRACTThe extrinsic sensory stimulation plays a crucial role in the formation and integration of sensory modalities during development. Postnatal behavior is thereby influenced by the type and timing of presentation of prenatal sensory stimuli. In this study, fertilized eggs of white Leghorn chickens during incubation were exposed to either species‐specific calls or no sound. To find the prenatal critical period when auditory stimulation can modulate visual system development, the former group was divided into three subgroups: in subgroup A (SGA), the stimulus was provided during embryonic day (E)10 to E16, in SGB E17‐ hatching, and in SGC E10‐hatching. The auditory and visual perceptual learning was recorded at posthatch day (PH) 1–3, whereas synaptic plasticity (evident from synaptophysin and PSD‐95 expression), was observed at E19, E20, and PH 1–3. An increased number of responders were observed in both auditory and visual preference tests at PH 1 following stimulation. Although a decrease in latency of entry and an increase in total time spent were observed in all stimulated groups, it was most significant in SGC in auditory preference and in SGB and SGC in visual preference test. The auditory cortex of SGC and visual Wulst of SGB and SGC revealed higher expression of synaptic proteins, compared to control and SGA. A significant inter‐hemispheric and gender‐based difference in expression was also found in all groups. These results indicate facilitation of postnatal behaviour and synaptogenesis in both auditory and visual systems following prenatal repetitive auditory stimulation, only when given during prenatal critical period of development. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 688–701, 2013
Zinc Complexes of Bipyrrolidine‐Based Diamine‐Diphenolato and Diamine‐Diolato Ligands: Predetermination of Helical Chirality Around Tetrahedral Centres
Authors: Sergeeva Ekaterina , Press Konstantin , Goldberg Israel , Kol Moshe 
Published: May 2013

AbstractThe coordination chemistry of chiral tetradentate dianionic ligands of the diamine‐diphenolato and diamine‐diolato families having the (R,R)‐2,2′‐bipyrrolidine core around ZnII was investigated. Reactions with diethylzinc led to complexes of the type [{ONNO}Zn] for most ligands and to bridging dinuclear complexes of the type [μ‐Lig4(ZnEt)2] for one of the diamine‐diolato ligands. Reactions with bis(hexamethyldisilazide)zinc led to complete conversions. Most complexes were obtained as mononuclear complexes. The least bulky Salan ligand, Lig3, led to an equilibrium between mononuclear and dinuclear complexes in noncoordinating solvents. All ligands were found to wrap around the tetrahedral zinc with very high diastereoselectivities supporting predetermined chiral induction from the bipyrrolidine core to the helical ligand wrapping. Molecular structures determined by single‐crystal X‐ray diffraction for two complexes of the type [{ONNO}Zn] substantiated the predicted Δ wrapping of the (R,R)‐based ligands. In contrast, representative Salan and diamine‐diolato ligands assembled around the trans‐1,2‐diaminocyclohexane core led to diastereomer mixtures of the corresponding complexes.
Bile Acid Derived Tropos Vaulted Bi­naphth­ylphosphites: Synthesis, Stereo­chemical Characterization and Complexation to Rhodium
Authors: Jumde Varsha R. , Iuliano Anna 
Published: May 2013

AbstractThree different 2,2′‐binaphthylphosphites were synthesized, starting from suitable derivatives of cholic or deoxycholic acids and 1,1′‐dihydroxy‐2,2′‐binaphthyl, and their stereochemical features were analyzed by CD and NMR spectroscopy. The spectroscopic data clearly demonstrate the capability of the cholestanic backbone to induce a M prevalent screw sense to the flexible binaphthyl moiety, giving rise to tropos ligands. The extent of the prevalence of the M sense of twist depends on the position at which the binaphthylphosphite moiety is linked on the bile acid skeleton. The three phosphites were mixed with [Rh(COD)2][BF4] and the resulting complexes were analyzed by variable temperature 31P NMR spectroscopy, thereby obtaining information on their stereochemical characteristics, which reflect the different asymmetric induction capability of the ligands.
Optically Active Monoacylglycerols: Synthesis and Assessment of Purity
Authors: Chen Chao‐Yuan , Han Wei‐Bo , Chen Hui‐Jun , Wu Yikang , Gao Po 
Published: May 2013

AbstractDespite their simple structures, synthesis of 1(or 3)‐acyl‐sn‐glycerols remains a challenge that cannot be ignored because of facile acyl migrations, which not only complicate the synthesis but also make direct GC or HPLC analysis unfeasible. Assessment of the optical purity of monoacylglycerols has, to date, relied almost exclusively on specific rotation data, which are small in value and thus insensitive to impurities. Now, a simple means to “magnify” the small specific rotations has been found, along with practical methods for the measurement of both 1,2‐ and 1,3‐acyl migrations, which offer a convenient and straightforward alternative to Mori's NMR analysis of Mosher esters. With the aid of these methods, a range of conditions for deacetonide removal were examined en route to the synthesis of two natural monoacylglycerols. Refined hydrolysis conditions, along with useful knowledge about the solubility and reactivity of substrates with an ultra long alkyl chain are also presented.
A Modular Approach to Build Macrocyclic Diversity in Aminoindoline Scaffolds Identifies Antiangiogenesis Agents from a Zebrafish Assay
Authors: Chamakuri Srinivas , Guduru Shiva Krishna Reddy , Pamu Sreedhar , Chandrasekar Gayathri , Kitambi Satish Srinivas , Arya Prabhat 
Published: May 2013

AbstractA modular approach to explore the macrocyclic chemical space around an aminoindoline scaffold is developed. This is achieved by incorporating an amino acid moiety and subsequent “stitching technology”. Through screening of a zebrafish assay, several antiangiogenesis agents are identified.
Metal‐Free Dioxygenation of Enecarbamates Mediated by a Hypervalent Iodine Reagent
Authors: Bekkaye Mathieu , Su Yingpeng , Masson Géraldine 
Published: May 2013

AbstractA general method for the vicinal dioxygenation of enecarbamates was developed by using PhI(OAc)2 as the sole oxidant under extremely mild conditions, thus avoiding starting material decomposition. This methodology, which is an alternative to common dioxygenation processes catalyzed by transition metals, provides easy access to functionalized β‐acetoxy‐α‐amido ethers and α‐amido‐β‐oxytetrahydrofurans in moderate to good yields.
Price Discovery in Futures and Options Markets
Authors: Boyd Naomi , Locke Peter 
Published: May 2013

AbstractWe evaluate price discovery in the natural gas futures and futures options markets using a transaction‐based approach. By sampling market maker prices, we allow for a distinction between market maker buy and sell futures prices, both directly from trades in the futures market, and futures prices implied by trades in the options market. Information shares are compared between futures and options markets as well as within the options market. Given the common architecture of the two markets, as expected we find little price information generated in the options market. Within the options market, the highly levered out‐of‐the‐money options offer less price discovery than other options. We attribute this to the higher transaction costs of out‐of‐the‐money options. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark 34:853–867, 2014
Financing—Renewables: Renewable Energy Markets Challenged, but Strategies for Profit Still Exist
Authors: Templeman Andre , Ogra Rohit , Struk Mark , Crosby Bryan 
Published: May 2013

AbstractThe US market for renewable energy development faces significant challenges in the coming months and years as energy production from fossil fuels—namely, natural gas supply coming from tight shale plays—sees a dramatic increase and state renewable portfolio standard (RPS) mandates are scaled back or at least not increased substantially.
Diel patterns of oceanic dimethylsulfide (DMS) cycling: Microbial and physical drivers
Authors: Galí Martí , Simó Rafel , Vila‐Costa Maria , Ruiz‐González Clara , Gasol Josep M. , Matrai Patricia 
Published: May 2013

AbstractDimethylsulfide (DMS) is a biogenic gas with potential climatic effects, and its marine emission depends on the interplay between microbial activity and physical forcing in the oceanic upper mixed layer. We investigated the diel cycling patterns of DMS and its precursor dimethylsulfoniopropionate (DMSP) in four experiments (28 to 48 h long) performed in mesotrophic to ultraoligotrophic Mediterranean and Sargasso Sea waters. Samples taken every 4 or 6 h were analyzed for dimethylated sulfur pools and incubated to measure DMS and DMSP cycling rates, as well as primary and bacterial production. In all four experiments, DMS budgets showed pronounced day versus night variability. In the three summer experiments, gross community DMS production (GPDMS) increased by twofold to threefold from nighttime to daytime, peaking 0–4 h after solar noon. This excess GPDMS was balanced by higher photochemical and microbial sinks during the day, effectively buffering DMS concentrations. In the only winter experiment, GPDMS exhibited opposed temporal dynamics and peaked at nighttime in parallel to total DMSP consumption. Community DMSP to DMS conversion yields were generally <10% throughout the winter experiment and at night in summer, and increased to >15% (even >50%) during the day in summer, presumably due to phytoplankton radiative stress. Our data suggest that (1) diel variability should be taken into account in process studies, diagnostic, and prognostic models of DMS cycling and (2) the community DMS yield is a key variable that defines characteristic DMS cycling regimes.
The State of the HR Profession
Authors: Ulrich Dave , Younger Jon , Brockbank Wayne , Ulrich Michael D. 
Published: May 2013

AbstractWe want to create a new narrative about the human resource (HR) profession. HR professionals have often been plagued with self‐doubts, repeatedly re‐exploring HR's role, value, and competencies. If HR is to fully (and finally) become a profession, these self‐doubts need to be replaced with informed insights. These informed insights should be based more on global data than personal perceptions so that the emerging narrative for the HR profession has both substance and meaning.
Firm Productivity Moderated Link Between Human Capital and Compensation: The Significance of Task‐Specific Human Capital
Authors: Schulz Eric , Chowdhury Sanjib , Van de Voort David 
Published: May 2013

AbstractThe human capital of a firm as manifested by employee knowledge and experience represents a key resource of a firm's capabilities. Prior empirical studies have found that firms composed of high levels of human capital experience superior firm performance. Human capital theory proposes that an individual's general or firm‐specific human capital is positively related to compensation. However, empirical studies examining firm‐specific human capital's association with higher employee compensation have been inconclusive. The current study proposes that firm‐specific human capital be categorized as task‐specific and non‐task‐specific. Employees accumulate task‐specific human capital through duties conducted in their current position. Non‐task‐specific human capital represents experiences gained in prior positions to an employee's current job within the firm. Utilizing human capital data from 38,390 employees representing 76 firms in the IT sector, this study examines the association between forms of human capital and employee compensation at different levels of firm productivity. Results show that task‐specific human capital is associated with higher employee compensation. In addition, firm productivity moderates this association.