bluuebunny/crossref_metadata_2025_split huggingface dataset:
Longer you play, the more hostile you feel: examination of first person shooter video games and aggression during video game play
Authors: Barlett Christopher P. , Harris Richard J. , Baldassaro Ross 
Published: August 2007

AbstractThis study investigated the effects of video game play on aggression. Using the General Aggression Model, as applied to video games by Anderson and Bushman, [2002] this study measured physiological arousal, state hostility, and how aggressively participants would respond to three hypothetical scenarios. In addition, this study measured each of these variables multiple times to gauge how aggression would change with increased video game play. Results showed a significant increase from baseline in hostility and aggression (based on two of the three story stems), which is consistent with the General Aggression Model. This study adds to the existing literature on video games and aggression by showing that increased play of a violent first person shooter video game can significantly increase aggression from baseline. Aggr. Behav. 33:486–497, 2007. © 2007 Wiley‐Liss, Inc.
Distributed rereading can hurt the spacing effect in text memory
Authors: Verkoeijen Peter P. J. L. , Rikers Remy M. J. P. , Özsoy Binnur 
Published: August 2007

AbstractThe spacing effect refers to the commonly observed phenomenon that memory for spaced repetitions is better than for massed repetitions. In the present study, we examined this effect in students' memory for a lengthy expository text. Participants read the text twice, either in immediate succession (massed repetition), with a 4‐day interstudy interval (spaced short), or with a 3.5‐weeks interstudy interval (spaced long). Two days after the second study trial, all participants were tested. The results demonstrated that students in the spaced‐short condition remembered more of the content than those in the massed condition. By contrast, students in the spaced‐long condition remembered as much as students in the massed condition. These results were interpreted in terms of a theoretical framework, which combines mechanisms of encoding variability and study‐phase retrieval to account for the spacing effect. Copyright © 2007 John Wiley & Sons, Ltd.
Mathematics‐aided quantitative analysis of diffusion characteristics of pHEMA sponge hydrogels
Authors: Lou X. , Wang S. , Tan S. Y. 
Published: August 2007

AbstractThis study reports the current progress in quantitative analysis of the release characteristics of pHEMA spongy hydrogels using prednisolone 21‐hemisuccinate sodium salt as a model drug. Extraction of effective diffusion coefficients of the drug from various pHEMA matrices was made using a novel mathematical model that handles both boundary layer and initial burst effects. Drug loading level and entrapment efficiency were also determined. The computed diffusion coefficients and the drug loading capacity in relation to the device porous structure and drug concentration of the loading solution, as well as the size of device are discussed. Mathematical modelling proves to be a powerful tool not only for establishing and interpreting structure and performance relationships but also for handling experimental ambiguity. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Fouling mechanisms of model polymeric substances
Authors: Negaresh E. , Le‐Clech P. , Chen V. 
Published: August 2007

AbstractExtracellular polymeric substances (EPS) and soluble microbial products (SMP) have been identified as the main foulants in membrane bioreactor (MBR) operation. For a better understanding of the fouling mechanisms of these substances, filtration of model solutions with submerged membranes was carried out. Filtration was conducted following the flux‐stepping method. In this work alginate was used as a model for polysaccharide, bovine serum albumin (BSA) as a model for protein, and yeast (washed and unwashed) and bentonite were used for suspended solid contents. Fouling behaviours and rejection propensities were also assessed for one‐component and two‐component solutions and provided explanations for fouling mechanisms of carbohydrate and its interaction with protein and membrane in MBR systems. During the filtration of most foulants (except BSA), introducing the alginate increased the reversible fouling more than the irreversible one. In addition, a different behaviour was observed for the mixture of BSA and alginate. Fouling rate was also affected by the introduction of alginate. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Incidental catch of marine turtles by Italian trawlers and longliners in the central Mediterranean
Authors: Casale Paolo , Cattarino Lorenzo , Freggi Daniela , Rocco Massimiliano , Argano Roberto 
Published: August 2007

Abstract
The fishing effort and turtle catch of vessels harbouring at Lampedusa island and fishing in the wider central Mediterranean area was monitored using a voluntary logbook programme. Two large trawlers were monitored between 2003 and 2005 and six small vessels using trawl nets, pelagic longline or bottom longline were monitored in the summer 2005.
The observed turtle catch rates of pelagic longline and bottom trawl were among the highest recorded in the basin, and high catch rates by bottom longline were observed too. This suggests that the area contains major oceanic and neritic habitats for the loggerhead turtle Caretta caretta in the Mediterranean Sea.
When fishing effort is considered, these results suggest a very high number of captures by Italian trawlers and longliners in the area, as well as by fleets from other countries. This is reason of concern for the conservation of the loggerhead turtle within the Mediterranean Sea.
Different fishing gear have different technical/operational characteristics affecting turtle catch and mortality and the present knowledge about associated parameters of these gear varies too.
All this considered, specific actions are recommended: (i) an awareness campaign to fishermen to reduce post‐release mortality, (ii) technical modifications to pelagic longline gear to reduce turtle catch, (iii) further investigation into turtle bycatch in all fishing gear, with priority given to bottom longline fishing and quantification of mortality caused by trawlers, (iv) assessment of the turtle populations affected by fishing activity in the area, and (v) international cooperation in undertaking threat assessments, and implementing regulations, management measures and monitoring.
Copyright © 2007 John Wiley & Sons, Ltd.
Asymmetric Hydrogenations One by One: Differentiation of up to Three β‐Ketocarboxylic Acid Derivatives Based on Ruthenium(II)–Binap Catalysis
Authors: Kramer Rainer , Brückner Reinhard 
Published: August 2007

AbstractNoyori‐type reductions of pairs of β‐ketoamides and β‐ketoesters with elemental hydrogen (4 bar) proceeded substrate by substrate. When Et2NH2+[{RuCl(S)‐binap}2](μ‐Cl)3− was employed as a catalyst in a methanol or ethanol solution, the substrates were reduced at room temperature in the order β‐ketopyrrolidide ≥ β‐ketopiperidide ≥ β‐keto(N,N‐diethylamide) > β‐keto(alkyl esters) > β‐keto(oligofluoroalkyl esters). This is the first time that β‐ketoamides have been reduced asymmetrically (91 to >98 % ee) under such mild conditions. Monitoring the concentrations of these β‐ketocarboxyl acid derivatives and their respective hydrogenation products over the course of time showed that the most electron‐rich substrate is captured by the catalyst preferentially and exothermically; whether this occurs reversibly or irreversibly remains to be determined. The hydrogenation product is subsequently formed. The last transformation includes the rate‐determining step. The combination of these events explains why starting from appropriate mixtures of substrates a “first‐choice substrate” reacted from early on while the “second‐choice substrate” stayed virtually untouched over an extended period of time and reacted no earlier than after the “first‐choice substrate” had disappeared. From then onward, however, the “second‐choice substrate” also reacted relatively rapidly.
Synthesis of a Bis‐macrocycle Containing Two Back‐to‐Back Rigidly Connected 1,10‐Phenanthroline Units as a Central Core and its Incorporation in a Handcuff‐Like Catenane
Authors: Frey Julien , Kraus Tomáš , Heitz Valérie , Sauvage Jean‐Pierre 
Published: August 2007

AbstractA bis‐macrocycle containing two back‐to‐back connected 1,10‐phenanthroline chelates has been prepared. The synthetic strategy involves the preparation of a monocyclic precursor consisting of a 1,10‐phenanthroline‐5,6‐dione fragment incorporated in a 30‐membered ring. This important intermediate has been prepared via two distinct routes, both strategies relying on the use of a ketal as a 1,2‐dione protective group. A four‐component condensation reaction between two molecules of the macrocyclic dione and two equivalents of ammonia (used in large excess) in the presence of a reducing agent (Na2S2O4) leads to the desired bis‐ring in good yield. The most direct synthetic route allows preparation of the bis‐macrocycle in seven steps from 1,10‐phenanthroline in an overall yield of 14 %. Using the now well‐established “gathering and threading” effect of copper(I), a doubly threaded species could be obtained in quantitative yield, in which each ring of the bis‐macrocycle is threaded by a “molecular string”. These fragments bear terminal allylic groups, which are used to prepare the final catenane by performing a double ring‐closing metathesis reaction. This final cyclisation reaction is high yielding and affords the desired catenane consisting of a bis‐macrocycle of which the two cyclic units are threaded by a large ring. The compound has been fully characterised by classical techniques. Electronic spectroscopy and electrochemical measurements suggest that the two copper complex subunits do not interact electronically, in spite of the aromatic nature of the bridging ligand between the two metal centres.
N‐Heterocyclic Carbenes of 5‐Haloindazoles Generated by Decarboxylation of 5‐Haloindazolium‐3‐carboxylates
Authors: Schmidt Andreas , Snovydovych Bohdan , Habeck Tobias , Dröttboom Petra , Gjikaj Mimoza , Adam Arnold 
Published: August 2007

AbstractSyntheses and properties of 5‐fluoro‐, chloro‐ bromo‐, and iodo‐substituted 1,2‐dimethyl indazolium‐3‐carboxylates as new representatives of pseudo‐cross‐conjugated heterocyclic mesomeric betaines are described, and results of an X‐ray single crystal analysis of the nonhalogenated parent compound are presented. These betaines decarboxylate on heating to yield 5‐halo‐1,2‐dimethyl‐indazol‐3‐ylidenes, which can be trapped by protons, sulfur, and 2,4‐dichlorophenylisocyanate, respectively. The decarboxylation is studied by electrospray‐ionization mass spectrometry, NMR spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
(5‐Imino‐4,5‐dihydro‐3H‐pyrrol‐2‐yl)amines as Sterically Restrained 1,3,5‐Triazapenta‐1,3‐dienes: Useful Building Blocks for the Synthesis of Oligonitriles
Authors: Marihart Edgar A. , Greving Jan‐Bernd , Fröhlich Roland , Würthwein Ernst‐Ulrich 
Published: August 2007

Abstract(5‐Imino‐4,5‐dihydro‐3H‐pyrrol‐2‐yl)amines 2 may be considered as sterically restrained 1,3,5‐triazapenta‐1,3‐dienes. They were easily prepared from 2,2,3,3‐tetramethylsuccinonitrile (1) and lithium amides with subsequent aqueous workup to give the monocyclic compounds 2a–d and the bi‐ and tricyclic compounds 2e–g. X‐ray diffraction studies of 2c and 2d, which contain a primary NH2 group, reveal the existence of homodimers held together with paired hydrogen bonds in the solid state. Trapping of the lithiated intermediate 2a‐Li by benzoyl chloride provided access to the 1‐oxa‐3,5,7‐triazahepta‐1,3,5‐triene 3b. It is characterized in the solid state by a planar heterocyclic subunit and a strongly twisted N‐acylamidine part. With 1‐oxa‐3,5‐diazinium salts 4, compounds 2a,b,d or 2a‐Li reacted to give 1‐oxa‐3,5,7,9,11‐pentaazaundeca‐1,3,5,7,9‐pentaenes 5a–d. Here again, the planar heterocyclic parts combine with longer, twisted (not helical) oligonitrile moieties. The X‐ray diffraction study of 5d indicates intermolecular N–H···O=C hydrogen bonding in the solid state, producing one‐dimensional strands. In a similar way as 1 the trinitrile 2,3,5‐trimethyl‐2,3,5‐tricyanohexane (6), a byproduct of the thermal decomposition of azoisobutyronitrile (AIBN), reacted with lithium benzylamide to give a bicyclic intermediate which was successfully converted into the corresponding 1‐oxa‐3,5,7,9,11,13‐hexaazatrideca‐1,3,5,7,9,11‐hexaene 7 when treated with 1‐oxa‐3,5‐diazinium salt 4b. Similar to 5d, this extended oligonitrile forms one‐dimensional hydrogen‐bonded polymers in the solid state. Its UV spectrum (λmax = 286 nm) is interpreted in terms of a planar conjugated π–π* azapolyene substructure forced into planarity by the heterocycles.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Fluorous Synthesis of Yuehchukene by α‐Lithiation of Perfluoroalkyl‐Tagged 1‐(Arylsulfonyl)indole with Mesityllithium
Authors: Naka Hiroshi , Akagi Yusuke , Yamada Kyoko , Imahori Tatsushi , Kasahara Takahiro , Kondo Yoshinori 
Published: August 2007

AbstractLithiation chemistry has not been well explored in fluorous synthesis because of the lack of appropriate base‐resistant fluorous tags; we recently developed a perfluoroalkylated arylsulfonyl tag for the protection of the indole ring nitrogen atom. Mesityllithium was found to be a suitable reagent for the α‐lithiation of perfluoroalkyl‐tagged 1‐(arylsulfonyl)indole, and the fluorous synthesis of yuehchukene was accomplished efficiently using this method as a key step. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Drug‐induced Myc‐mediated apoptosis of cancer cells is inhibited by stress protein Hsp70
Authors: Afanasyeva Elena A. , Komarova Elena Yu. , Larsson Lars‐Gunnar , Bahram Fuad , Margulis Boris A. , Guzhova Irina V. 
Published: August 2007

AbstractThe Myc oncoprotein serves a dual function by stimulating cells both towards growth and apoptosis. The latter functions are often abrogated during tumor development. The Hsp70 stress protein is a potent anti‐apoptotic molecule, but its potential role in protecting cells from Myc‐mediated apoptosis has not been investigated. Our results show that activated Myc potentiated apoptosis induced by the cancer drugs etoposide (ETO) and camptothecin (CAMP) in v‐Myc‐expressing human U‐937 monoblastic cells and in Rat1 cells containing a conditionally active Myc/estrogen receptor (MycER) fusion protein. However, both heat shock and ectopic Hsp70 expression protected the cells from Myc‐mediated apoptosis after drug treatment in both systems. The increased susceptibility to the anti‐tumor drugs by activated Myc was enhanced by siRNA‐mediated knockdown of Hsp70 expression in U‐937 cells. Addressing the mechanisms by which Myc and Hsp70 promotes and inhibits drug‐induced apoptosis, respectively, we found that v‐Myc stimulated cytochrome c release and activation of effector caspase‐9, ‐3 and ‐7, but not of initiator caspase‐8. Inhibition of caspase‐9 specifically reduced v‐Myc‐stimulated apoptosis, whereas inhibition of caspase‐8 and ‐3/7 reduced apoptosis both in v‐myc‐expressing and parental ETO‐treated U‐937 cells. Interestingly, Myc‐stimulated activation of effector caspases was inhibited, but cytochrome c release was not affected by Hsp70 expression, suggesting that Hsp70 interferes with the proapoptotic function of Myc downstream of mitochondria, at the level of caspase‐9 and downstream caspases. In conclusion, Hsp70 seems to have key function in inhibition of apoptosis mediated by Myc and may therefore play an important role in Myc‐driven oncogenesis. © 2007 Wiley‐Liss, Inc.
Model‐free evaluation of directional predictability in foreign exchange markets
Authors: Chung Jaehun , Hong Yongmiao 
Published: August 2007

AbstractWe examine directional predictability in foreign exchange markets using a model‐free statistical evaluation procedure. Based on a sample of foreign exchange spot rates and futures prices in six major currencies, we document strong evidence that the directions of foreign exchange returns are predictable not only by the past history of foreign exchange returns, but also the past history of interest rate differentials, suggesting that the latter can be a useful predictor of the directions of future foreign exchange rates. This evidence becomes stronger when the direction of larger changes is considered. We further document that despite the weak conditional mean dynamics of foreign exchange returns, directional predictability can be explained by strong dependence derived from higher‐order conditional moments such as the volatility, skewness and kurtosis of past foreign exchange returns. Moreover, the conditional mean dynamics of interest rate differentials contributes significantly to directional predictability. We also examine the co‐movements between two foreign exchange rates, particularly the co‐movements of joint large changes. There exists strong evidence that the directions of joint changes are predictable using past foreign exchange returns and interest rate differentials. Furthermore, both individual currency returns and interest rate differentials are also useful in predicting the directions of joint changes. Several sources can explain this directional predictability of joint changes, including the level and volatility of underlying currency returns. Copyright © 2007 John Wiley & Sons, Ltd.
A mechanistic view on the evolutionary origin for centrin‐based control of centriole duplication
Authors: Salisbury Jeffrey L. 
Published: August 2007

AbstractMounting evidence implicates the protein centrin as a key regulator of centriole duplication, yet it remains to be determined just how centrin functions in this process. Recent studies suggest that centrin exerts both spatial and temporal control over centriole duplication through its role as a component of centriole precursor structures and through periodic cell‐cycle specific changes in its abundance. Here, an overview of centrin and its role in centrosome dynamics is presented. Finally, a speculative model for just how centrin may operate to control centriole duplication is proposed with the intention to stimulate future advances in this area. This model provides an evolutionary basis for the preservation of essential features of the yeast spindle pole body (SPB) with the origin of the complex structure of the mammalian centriole. J. Cell. Physiol. 213: 420–428, 2007. © 2007 Wiley‐Liss, Inc.
Positional lumbar imaging using a positional device in a horizontally open‐configuration MR unit—Initial experience
Authors: Hayashida Yoshiko , Hirai Toshinori , Hiai Yasuhiro , Kitajima Mika , Imuta Masanori , Murakami Ryuji , Nakayama Yoshiharu , Awai Kazuo , Yamashita Yasuyuki , Takahashi Tetsuhiko , Hamada Kiyomi 
Published: August 2007

AbstractPurposeTo evaluate whether positional MR images of the lumbar spine, obtained with a horizontally open‐configuration MR unit, demonstrate positional changes of the dural sac, and to assess whether there are significant differences in positional changes between healthy volunteers and patients with chronic low back pain.Materials and MethodsThe study population consisted of 15 patients with chronic low back pain and 14 healthy volunteers. MR images were obtained using a horizontally open‐configuration 0.4‐T MR unit. After conventional lumbar MR examinations, images were obtained in the flexion, neutral, and extension positions, using a positioning device. The anteroposterior diameter of the dural sac at the level of each lumbar disk was measured in the three positions and quantitative data were compared.ResultsOur MR protocol was tolerated by all patients. In both patients and volunteers, the mean anteroposterior diameter of the dural sac was smaller in the extension positions than in the flexion positions. In the mean rate of change (RC) in the dural sac diameter at the site of the degenerated disks, the difference between the volunteers and patients was significant (P < 0.05). There was no significant difference in the mean RC between patients and volunteers without degenerative disks.ConclusionUsing a horizontally open‐configuration MR unit, positional MR imaging provided position‐dependent change of the dural sac. Positional changes at the site of the degenerated disks may be different in patients with and without chronic low back pain. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Low‐energy collision‐induced fragmentation of negative ions derived from ortho‐, meta‐, and para‐hydroxyphenyl carbaldehydes, ketones, and related compounds
Authors: Attygalle Athula B. , Ruzicka Josef , Varughese Deepu , Bialecki Jason B. , Jafri Sayed 
Published: August 2007

AbstractCollision‐induced dissociation (CID) mass spectra of anions derived from several hydroxyphenyl carbaldehydes and ketones were recorded and mechanistically rationalized. For example, the spectrum of m/z 121 ion of deprotonated ortho‐hydroxybenzaldehyde shows an intense peak at m/z 93 for a loss of carbon monoxide attributable to an ortho‐effect mediated by a charge‐directed heterolytic fragmentation mechanism. In contrast, the m/z 121 ion derived from meta and para isomers undergoes a charge‐remote homolytic cleavage to eliminate an •H and form a distonic anion radical, which eventually loses CO to produce a peak at m/z 92. In fact, for the para isomer, this two‐step homolytic mechanism is the most dominant fragmentation pathway. The spectrum of the meta isomer on the other hand, shows two predominant peaks at m/z 92 and 93 representing both homolytic and heterolytic fragmentations, respectively. 18O‐isotope‐labeling studies confirmed that the oxygen in the CO molecule that is eliminated from the anion of meta‐hydroxybenzaldehyde originates from either the aldehydic or the phenolic group. In contrast, anions of ortho‐hydroxybenzaldehyde and 2‐hydroxy‐1‐naphthaldehyde, both of which show two consecutive CO eliminations, specifically lose the carbonyl oxygen first, followed by that of the phenolic group. Anions from 2‐hydroxyphenyl alkyl ketones lose a ketene by a hydrogen transfer predominantly from the α position. Interestingly, a very significant charge‐remote 1,4‐elimination of a H2 molecule was observed from the anion derived from 2,4‐dihydroxybenzaldehyde. For this mechanism to operate, a labile hydrogen atom should be available on the hydroxyl group adjacent to the carbaldehyde functionality. Copyright © 2007 John Wiley & Sons, Ltd.
Modeling of microwave devices with space mapping and radial basis functions
Authors: Koziel Slawomir , Bandler John W. 
Published: August 2007

AbstractWe review recent developments in space mapping techniques for modeling of microwave devices. We present a surrogate modeling methodology that utilizes space mapping combined with radial basis function interpolation. The method has advantages both over the standard space mapping modeling methodology and the recently published space mapping modeling with variable weight coefficients. In particular, it provides accuracy comparable or better than the latter method and computational efficiency as good as the standard space mapping modeling procedure. A comparison between the space mapping modeling methodologies as well as application examples of optimization and statistical analysis of microwave structures is presented. Copyright © 2007 John Wiley & Sons, Ltd.