bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of neighborhood density and street connectivity on walking behavior: the Twin Cities walking study
Authors: Oakes J Michael , Forsyth Ann , Schmitz Kathryn H
Published: December 2007

A growing body of health and policy research suggests residential neighborhood density and street connectivity affect walking and total physical activity, both of which are important risk factors for obesity and related chronic diseases. The authors report results from their methodologically novel Twin Cities Walking Study; a multilevel study which examined the relationship between built environments, walking behavior and total physical activity. In order to maximize neighborhood-level variation while maintaining the exchangeability of resident-subjects, investigators sampled 716 adult persons nested in 36 randomly selected neighborhoods across four strata defined on density and street-connectivity – a matched sampling design. Outcome measures include two types of self-reported walking (from surveys and diaries) and so-called objective 7-day accelerometry measures. While crude differences are evident across all outcomes, adjusted effects show increased odds of travel walking in higher-density areas and increased odds of leisure walking in low-connectivity areas, but neither density nor street connectivity are meaningfully related to overall mean miles walked per day or increased total physical activity. Contrary to prior research, the authors conclude that the effects of density and block size on total walking and physical activity are modest to non-existent, if not contrapositive to hypotheses. Divergent findings are attributed to this study's sampling design, which tends to mitigate residual confounding by socioeconomic status.
Apoptosis is not the major death mechanism induced by celecoxib on rheumatoid arthritis synovial fibroblasts
Authors: Audo Rachel , Deschamps Véronique , Hahne Michael , Combe Bernard , Morel Jacques
Published: December 2007

Synovial hyperplasia in rheumatoid arthritis (RA) has been associated with apoptosis deficiency of RA fibroblast-like synoviocytes (FLSs). Celecoxib is a non-steroidal anti-inflammatory drug that has been demonstrated to induce apoptosis in some cellular systems. We have therefore examined the dose- and time-dependent effects of celecoxib on RA FLS viability. Treatment of RA FLSs with celecoxib for 24 hours reduced their viability in a dose-dependent manner. Analysis of celecoxib-treated RA FLSs for their content of apoptotic and necrotic cells by Annexin V staining and TO-PRO-3 uptake displayed only few apoptotic cells. Caspase 3, a key mediator of apoptosis, was not activated in celecoxib-treated RA FLSs, and the presence of specific caspase 3 or pan-caspase inhibitors did not affect celecoxib-induced cell death. Moreover, we could not detect other signs of apoptosis, such as cleavage of poly(ADP-ribose) polymerase, caspase 8 or 9, or DNA fragmentation. We therefore conclude that apoptosis is not the major death pathway in celecoxib-treated RA FLSs.
Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity
Authors: Redondo Maximino , Téllez Teresa , Roldan Maria J , Serrano Alfonso , García-Aranda Maria , Gleave Martin E , Hortas Maria L , Morell Miguel
Published: December 2007

Introduction

Overexpression of the apoptosis-related protein clusterin is associated with breast cancer development and tumor progression. We describe the use of clusterin-specific antisense oligonucleotides and antibodies to sensitize breast carcinoma cells to anticancer drugs routinely used in breast cancer therapy.

Methods

MCF-7 and MDA-MB-231 cells were treated with the oligonucleotide or antibody, chemotherapeutic agents (doxorubicin or paclitaxel), tamoxifen, or with combinations of these.

Results

Treatments that include antisense clusterin oligonucleotide or antibody to clusterin have been shown to reduce the number of viable cells more effectively than treatment with the drugs alone. We also demonstrate that dexamethasone pretreatment of breast cancer cell lines inhibits chemotherapy-induced cytotoxicity and is associated with the transcriptional induction of clusterin. However, anticlusterin treatment increases chemotherapy-induced cytotoxicity, even in the presence of glucocorticoids, suggesting a possible role for these proteins in glucocorticoid-mediated survival.

Conclusion

These data suggest that combined treatment with antibodies to clusterin or antisense clusterin oligodeoxynucleotides and paclitaxel, doxorubicin, or tamoxifen could be a novel and attractive strategy to inhibit the progression of breast carcinoma by regulation of the clusterin function. Moreover, glucocorticoid activation in breast cancer cells regulates survival signaling by the direct transactivation of genes like clusterin which encode proteins that decrease susceptibility to apoptosis. Given the widespread clinical administration of dexamethasone before chemotherapy, understanding glucocorticoid-induced survival mechanisms is essential for achieving optimal therapeutic responses.
Vasopressin in septic shock: effects on pancreatic, renal, and hepatic blood flow
Authors: Krejci Vladimir , Hiltebrand Luzius B , Jakob Stephan M , Takala Jukka , Sigurdsson Gisli H
Published: December 2007

Introduction

Vasopressin has been shown to increase blood pressure in catecholamine-resistant septic shock. The aim of this study was to measure the effects of low-dose vasopressin on regional (hepato-splanchnic and renal) and microcirculatory (liver, pancreas, and kidney) blood flow in septic shock.

Methods

Thirty-two pigs were anesthetized, mechanically ventilated, and randomly assigned to one of four groups (n = 8 in each). Group S (sepsis) and group SV (sepsis/vasopressin) were exposed to fecal peritonitis. Group C and group V were non-septic controls. After 240 minutes, both septic groups were resuscitated with intravenous fluids. After 300 minutes, groups V and SV received intravenous vasopressin 0.06 IU/kg per hour. Regional blood flow was measured in the hepatic and renal arteries, the portal vein, and the celiac trunk by means of ultrasonic transit time flowmetry. Microcirculatory blood flow was measured in the liver, kidney, and pancreas by means of laser Doppler flowmetry.

Results

In septic shock, vasopressin markedly decreased blood flow in the portal vein, by 58% after 1 hour and by 45% after 3 hours (p < 0.01), whereas flow remained virtually unchanged in the hepatic artery and increased in the celiac trunk. Microcirculatory blood flow decreased in the pancreas by 45% (p < 0.01) and in the kidney by 16% (p < 0.01) but remained unchanged in the liver.

Conclusion

Vasopressin caused marked redistribution of splanchnic regional and microcirculatory blood flow, including a significant decrease in portal, pancreatic, and renal blood flows, whereas hepatic artery flow remained virtually unchanged. This study also showed that increased urine output does not necessarily reflect increased renal blood flow.
A role for S1P signalling in axon guidance in theXenopusvisual system
Authors: Strochlic Laure , Dwivedy Asha , van Horck Francisca P. G. , Falk Julien , Holt Christine E.
Published: December 2007

Sphingosine 1-phosphate (S1P), a lysophospholipid, plays an important chemotactic role in the migration of lymphocytes and germ cells, and is known to regulate aspects of central nervous system development such as neurogenesis and neuronal migration. Its role in axon guidance, however, has not been examined. We show that sphingosine kinase 1, an enzyme that generates S1P, is expressed in areas surrounding the Xenopus retinal axon pathway, and that gain or loss of S1P function in vivo causes errors in axon navigation. Chemotropic assays reveal that S1P elicits fast repulsive responses in retinal growth cones. These responses require heparan sulfate, are sensitive to inhibitors of proteasomal degradation, and involve RhoA and LIM kinase activation. Together, the data identify downstream components that mediate S1P-induced growth cone responses and implicate S1P signalling in axon guidance.
Common functions of central and posterior Hox genes for the repression of head in the trunk ofDrosophila
Authors: Coiffier Delphine , Charroux Bernard , Kerridge Stephen
Published: December 2007

Hox genes are localised in complexes, encode conserved homeodomain transcription factors and have mostly been studied for their specialised functions: the formation of distinct structures along the anteroposterior axis. They probably derived via duplication followed by divergence, from a unique gene, suggesting that Hox genes may have retained a common function. The comparison of their homeodomain sequences groups Hox proteins into Anterior, Central and Posterior classes, reflecting their expression patterns in the head, trunk and tail, respectively. However, functional data supporting this classification are rare. Here, we re-examine a common activity of Hox genes in Drosophila: the repression of head in the trunk. First, we show that central and posterior Hox genes prevent the expression of the head specific gene optix in the trunk, providing a functional basis for the classification. Loss-of-function mutations of optix affect embryonic head development, whereas ectopic Optix expression strongly perturbs trunk development. Second, we demonstrate that the non-Hox genes teashirt,extradenticle and homothorax are required for the repression of optix and that Wingless signalling and Engrailed contribute to this repression. We propose that an evolutionary early function of Hox genes was to modify primitive head morphology with novel functions specialising the trunk appearing later on.
Bud specific N-sulfation of heparan sulfate regulatesShp2-dependent FGF signaling during lacrimal gland induction
Authors: Pan Yi , Carbe Christian , Powers Andrea , Zhang Eric E. , Esko Jeffrey D. , Grobe Kay , Feng Gen-Sheng , Zhang Xin
Published: December 2007

Preferential outgrowth of the bud cells forms the basis of branching morphogenesis. Here, we show that lacrimal gland development requires specific modification of heparan sulfates by Ndst genes at the tip of the lacrimal gland bud. Systemic and conditional knockout experiments demonstrate the tissue specific requirement of Ndst1 and Ndst2 in the lacrimal gland epithelial, but not mesenchymal, cells, and the functional importance of Ndst1 in Fgf10-Fgfr2b, but not of Fgf1-Fgfr2b, complex formation. Consistent with this, Fgf10-induced ectopic lacrimal gland budding in explant cultures is dependent upon Ndst gene dose, and epithelial deletion of Fgfr2 abolishes lacrimal gland budding, its specific modification of heparan sulfate and its phosphorylation of Shp2 (Ptpn11 - Mouse Genome Informatics). Finally, we show that genetic ablation of Ndst1, Fgfr2or Shp2 disrupts ERK signaling in lacrimal gland budding. Given the evolutionarily conserved roles of these genes, the localized activation of the Ndst-Fgfr-Shp2 genetic cascade is probably a general regulatory mechanism of FGF signaling in branching morphogenesis.
An FGF signaling loop sustains the generation of differentiated progeny from stem cells in mouse incisors
Authors: Klein Ophir D. , Lyons David B. , Balooch Guive , Marshall Grayson W. , Basson M. Albert , Peterka Miroslav , Boran Tomas , Peterkova Renata , Martin Gail R.
Published: December 2007

Rodent incisors grow throughout adult life, but are prevented from becoming excessively long by constant abrasion, which is facilitated by the absence of enamel on one side of the incisor. Here we report that loss-of-function of sprouty genes, which encode antagonists of receptor tyrosine kinase signaling,leads to bilateral enamel deposition, thus impeding incisor abrasion and resulting in unchecked tooth elongation. We demonstrate that sprouty genes function to ensure that enamel-producing ameloblasts are generated on only one side of the tooth by inhibiting the formation of ectopic ameloblasts from self-renewing stem cells, and that they do so by preventing the establishment of an epithelial-mesenchymal FGF signaling loop. Interestingly, although inactivation of Spry4 alone initiates ectopic ameloblast formation in the embryo, the dosage of another sprouty gene must also be reduced to sustain it after birth. These data reveal that the generation of differentiated progeny from a particular stem cell population can be differently regulated in the embryo and adult.
Effects of intake CO2 concentrations on fuel spray flame temperatures and soot formations
Authors: Nikolic D , Iida N
Published: December 2007

Exhaust gas recirculation (EGR) is an effective technique to reduce exhaust emission of nitrogen oxides (NOx) from diesel engines because it lowers the flame temperature in the combustion chamber. However, as NOx is reduced, the emission of particulate matter (PM) is increased, resulting from the lowered oxygen (O2) concentration. In this study, carbon dioxide (CO2) was used as a diluent to simulate the EGR process at ratios of 4:3, 9:5, and 14:3 per cent, thus making O2 concentrations 20, 19, and 18 per cent respectively. A single-cylinder rapid compression machine (RCM) was used to simulate diesel-type combustion. The ignition and the combustion processes of diesel fuel spray were observed by high-speed direct photography. Flame temperature (indication of NO formation) and the KL factor (an indication of soot concentration inside the fuel spray) were analysed by the two-colour method. The tests have demonstrated that maximum flame temperatures and soot generation were reduced with an increase in CO2 in the inlet charge, while at same time soot extinction times were increased.
The rapid development of a parallel hybrid propulsion control system by an online calibrating system
Authors: Wang B-H , Zhang J-W , Luo Y-G
Published: December 2007

The paper firstly describes the structure of the EQ6110HEV hybrid propulsion system. In order to accelerate the developing process of the hybrid propulsion system, an online calibrating/programming software has been simultaneously developed, and five functions of the system are helpful to develop the hybrid propulsion control system rapidly. Secondly, the online calibration system can monitor the state information of the hybrid propulsion system all the time, and modify the parametric maps or update the control programs. Based on the software package, the hybrid propulsion control system is developed and applied to the EQ6110HEV bus. Finally, experiments verify that the online calibration system is feasible and reliable, and can save about 30 per cent of the development time for the EQ6110HEV control system in comparison with that of the standard calibration system.
Dynamic properties of a driver's arms holding a steering wheel
Authors: Pick A J , Cole D J
Published: December 2007

Advances in automotive steering technology are motivating improved understanding of the dynamic interaction between the driver and the vehicle. This paper describes a method for identifying the dynamic properties of a driver's arms holding a steering wheel that is subjected to random torque disturbances. Data from eight test subjects are reported. A single-degree-of-freedom linear mass-damper-spring model is found to fit well to the measured torque-angle transfer functions at frequencies up to about 6 Hz. The effect of the driver opposing a steady offset torque and the effect of the driver co-contracting the muscles are investigated. Both actions are found to increase the stiffness and damping of the arms. The results contribute information about dynamic properties of the neuromuscular system in one of the most common human-machine interactions. The findings are relevant to the development of mathematical models of vehicle-driver dynamic interaction.
Predicting instantaneous exhaust flowrates in a constant volume sampling system
Authors: Bannister C D , Wallace F , Hawley J G , Brace C J
Published: December 2007

The constant volume sampling (CVS) method has been used to support vehicle emissions testing for over 25 years and the ‘bag’ measurement of emissions is the key method that is used for legislative purposes. Bag measurements provide a single figure for CO, CO2, and NOx emissions species for the complete drive cycle, but provide no information on the profile throughout the test. Instantaneous emissions measurements undertaken on a second-by-second basis are carried out to assess catalyst and engine system performance. The key measurement for this approach is the determination of the instantaneous exhaust mass flowrate, which allows the instantaneous gravimetric emissions to be calculated. Being able to accurately measure instantaneous emissions carries its own challenges, but the mixing effects in the CVS system when using the CO2 tracer technique have been shown to compromise significantly the capability to determine exhaust volume flowrates accurately. The predicted time responses of dilute CO2 concentration, and the resulting over-underestimate of tailpipe volume flow, display adequate agreement with experimental results. The magnitude of these errors was determined by measurement to be in the region of a 1500 per cent overestimate during tip-outs.
Optimization-based non-linear yaw moment control law for stabilizing vehicle lateral dynamics
Authors: Eslamian M , Alizadeh G , Mirzaei M
Published: December 2007

For a direct yaw moment control (DYC) system, using an external yaw moment that is as low as possible for stabilizing the vehicle-handling dynamics in the non-linear regimes can be considered as an important advantage. In this paper, to achieve this aim, an optimization-based side-slip tracking law is developed for DYC by the response prediction of a continuous non-linear vehicle dynamics model. A new desired model for the vehicle side-slip angle based on the linear vehicle model and tyre-road conditions is presented to be tracked by the controller. Two versions of the proposed non-linear control law are considered here and the performances of the two versions are compared. The derived control law has an analytical closed form in which online numerical computations in optimization are not required. The effectiveness of the designed controller is investigated by simulations of various manoeuvres using a developed, non-linear, full-vehicle dynamic model. The simulation results indicate that a satisfactory handling performance through a reduced external yaw moment can be achieved when the proposed optimal controller is applied.
An experimental investigation on optimized manifold injection in a direct-injection diesel engine with various hydrogen flowrates
Authors: Saravanan N , Nagarajan G
Published: December 2007

In recent days, the importance of environment and energy have been emphasized and, among various energy sources, the fuels for automotive use are attracting attention as they are closely related to day-to-day life. The fossil fuels that are widely used have some serious problems. One of these problems is the limit in reserves, the second problem is that they cannot be recycled, and another problem is that they produce many exhaust emissions. Therefore, various research studies on alternative fuels have been carried out to find a substitute for fossil fuels. Hydrogen, a non-carbon fuel, can meet zero-emission vehicles standards in the future and can be commercially used as a fuel, even though it has a number of technical and economical barriers.

For this paper, experiments were conducted to determine the optimized injection timing, injection duration, and injection quantity of the fuel for a manifold injected hydrogen-operated engine using diesel fuel as an ignition source for hydrogen. In the manifold injection technique, the optimized condition is the start of injection at gas exchange top dead centre (TDC) with an injection duration of 30° crank angle (CA) with a hydrogen flowrate of 7.5 l/min. The brake thermal efficiency is found to increase by 9 per cent compared with diesel fuel. Smoke is found to be lower for all hydrogen flowrates at all the load conditions owing to the absence of carbon in hydrogen. CO emissions vary from 0.03 to 0.12 vol% compared with from 0.08 to 0.14 vol% in a diesel fuel investigation. The exhaust gas temperature is found to be slightly higher by 7 per cent for the hydrogen operation compared with diesel fuel. Manifold injection systems with diesel fuel as the ignition source operate smoothly, show improved performance, and emit less pollution than diesel fuel does. It is possible to operate the direct-injection diesel engine smoothly using hydrogen in dual-fuel mode for the entire load spectrum.
Theoretical Studies of Chemical Reactions—A Fascinating World of Chemistry from Gas-Phase Elementary Reactions through Nanostructure Formation and Homogeneous Catalysis to Reactions of Metalloenzymes
Authors: Morokuma Keiji
Published: December 2007

Theoretical/computational studies of chemical reactions provide insight into detailed pathways and energy profiles that are not easily available from experiments. Although finding the potential energy profile for ground-state reactions of small molecular systems has become routine, there are many challenges in theoretical studies of chemical reactions. There are still a lot to learn from gas-phase reactions of small molecular systems, starting from an excited state and cascading though many potential surfaces via conical intersections. Molecular dynamics using quantum mechanical energy (QM/MD) was found to be an ideal tool for study of reactions occurring far from equilibrium, such as formation of fullerenes from small carbon fragments and growth of carbon nanotubes. Challenges in theoretical studies of homogeneous catalysis are subtle ligand effects, involvement of multiple spin states and cooperative effects of multiple metal centers. Discussions here cover stories on activation of molecular nitrogen by zirconium complexes, olefin epoxidation by Salen complexes and reactions of tri-ruthenium complexes. Metalloenzymatic reactions have been discussed using protein models with ONIOM QM:MM approaches as well as active site models. Cases are presented where the enzymatic environment makes rather small effects, where it makes energetically significant effects and where it participates positively into the reaction coordinate.
Studies of Organic Protein Cofactors Using Electron Paramagnetic Resonance
Authors: Weber Stefan , Bittl Robert
Published: December 2007

The elucidation of structural and electronic aspects of paramagnetic organic cofactors in their protein surroundings and related model compounds is a topic of widespread interest. In this field, electron paramagnetic resonance (EPR) spectroscopy, especially in conjunction with high-resolution electron-nuclear double resonance (ENDOR) is an important tool, allowing us to analyze details of the distribution of the unpaired electron spin, which is influenced by the interaction between the cofactor and its immediate environment, as well as to characterize paramagnetic intermediate states in the course of the protein action. In this account, investigations are reported in which EPR/ENDOR methods have contributed significantly to answering questions on mechanistic and structural aspects of protein function. Emphasis is given to in-depth characterizations of electronic and spatial structures of radical cofactors and their positioning relative to substrate molecules. After a brief introduction, covering some of the trends of modern EPR/ENDOR method development, we will focus, as examples, on characterizations of quinone-type and flavin cofactors in two proteins, (i) quinoprotein alcohol dehydrogenase, and (ii) DNA photolyase.
Formation, Structure, and Stability of α- and β-Cyclodextrin Inclusion Complexes of Phenol and Benzoic Acid Derivatives in Vacuo and in Water
Authors: Song Le Xin , Wang Hai Ming , Xu Peng , Zhang Zi Qiang , Liu Qing Qing
Published: December 2007

Inclusion complexations of α- and β-cyclodextrin (CD) with a series of phenol and benzoic acid derivatives both in vacuo and in water were investigated by semiempirical PM3 method. The inclusion systems with a higher negative value of complexation energy or interaction energy were found to have also a larger value of formation constant (Kf) in aqueous solution. The stability of β-CD inclusion complexes depended on the size/shape-fit between host and guest. A good size fitting between the volume of a guest molecule and the free space size of CD cavity effectively improved the stability of CD inclusion complex of the guest. Even though there was no appropriate molar volume ratio (MVR) of a guest to β-CD cavity, a good structural matching between the shape of a guest molecule and the arrangement of β-CD cavity should also obviously improve the stability of β-CD inclusion complex of the guest. Moreover, the CD cavity size exerted a big influence on the stability of these supramolecular complexes. There was an energetic advantage of larger than 45 kJ mol−1 in favor of the intermolecular complexations between α-CD and mono-ortho-substituted phenol derivatives relative to phenol or mono-para-substituted phenol derivatives.
DFT Analysis of Cubane-Type FeIr3S4 Clusters. Dinitrogen Binding and Activation at the Tetrahedral Fe Site
Authors: Kozlowski Pawel M , Shiota Yoshihito , Gomita Satomi , Seino Hidetake , Mizobe Yasushi , Yoshizawa Kazunari
Published: December 2007

The electronic and structural properties of the cubane-type mixed-metal sulfido clusters with a FeIr3S4 core and possible dinitrogen binding and activation were analyzed by density functional theory (DFT) calculations. Five different charges of the cluster and manifold of the electronic states were investigated. For each charge under consideration (+2,+1,0,−1,−2) systematic analysis of structural and electronic properties was carried out. The DFT calculations show that both Fe–N and N≡N bond lengths correlate with the total charge of the cluster. The length of the Fe–N bond decreased, whereas the N≡N bond length increased with the number of added electrons. However, only noticeable elongation of the N≡N bond was observed when the charge of the cluster became negative. Similar analysis was extended to species that have protonated dinitrogen bond. The results obtained from the DFT analysis are useful in considering the principles of the reduction of dinitrogen to ammonia at a single metal center.
Ferromagnetic Interactions in Non-Kekulé Polymers
Authors: Hatanaka Masashi , Shiba Ryuichi
Published: December 2007

Ferromagnetic interactions in non-Kekulé polymers were analyzed under the periodic boundary condition. We transformed Bloch functions of non-bonding crystal orbitals (NBCOs) into Wannier functions. The product of the ν-th and (ν+1)-th Wannier functions was defined as PNBCOν,ν+1 (product of NBCOs). In so-called nondisjoint-type polymers, ferromagnetic ground states resulted from instabilities of anti-parallel-spin states in PNBCOν,ν+1. The instabilities consisted of “on-site term” and “through-space term.” The former corresponded to squared amplitude of the same atomic site on PNBCOν,ν+1, and the latter corresponded to antibonding-through-space interactions in PNBCOν,ν+1. The instabilities led to ferromagnetic-spin alignment. On the other hand, in so called disjoint polymers, such instabilities did not emerge.
Synergistic Extraction and Solution Structures of Ternary Complexes of Lanthanoids with 2-Thenoyltrifluoroacetone and Linear Poly(oxyethylene) in 1,2-Dichloroethane
Authors: Gagabe Gene Frederick , Satoh Yuta , Satoh Keiichi , Sawada Kiyoshi
Published: December 2007

Synergistic extraction of thenoyltrifluoroacetone (tta) complexes of 14 trivalent lanthanoids (Ln3+) into 1,2-dichloroethane with linear poly(oxyethylene) compounds (POE) was investigated at 25.0 °C, where the linear POE [HO–(CH2CH2O–)nR] are monodispersed DEOn (R=C12H25; n=4, 6, and 8) and polydispersed TX-100 (R = octylphenyl; nave=9.6). Equilibrium studies showed a 1:1 adduct complex with POE compound, Ln(tta)3·(POE), formed in the organic phase. The adduct formation constant, βadd, increased as the ionic radius of lanthanoid increased for any kind of POE. The very high stability of the 18-crown-6 adducts is explained by the incorporation of Ln3+ ion into the cavity of the crown ether. Adduct formation constants of the POE having short ethylene oxide (EO) chain, such as DEO4 and 12-crown-4, were fairly small; thus, it was estimated that those coordinate to the metal ion as a bidentate or tridentate ligand. Relatively large values of βadd of long chain POE (n≥6) indicate the indirect outer-sphere interaction of the uncoordinated residual EO units with the metal ion. Adduct formation with linear POEs significantly reduced the difference in extraction constants among the lanthanoid ions. Therefore, this synergistic extraction system is advantageous for the separation of lanthanoid ions as a group from other metal ions.
The β-Silicon Effect. III. Substituent Effects of the β-Si-Aryl Moiety in the Solvolysis of 1-Aryl-2-(aryldimethylsilyl)ethyl 3,5-Dinitrobenzoates
Authors: Fujio Mizue , Alam Md Ashadul , Umezaki Yuzo , Kikukawa Kiyoshi , Fujiyama Ryoji , Tsuno Yuho
Published: December 2007

Solvolysis rates of 2-[dimethyl(X-phenyl)silyl]-1-(Y-phenyl)ethyl 3,5-dinitrobenzoates were determined conductimetrically in 60% (v/v) aqueous ethanol. The effects of substituents X in the β-arylsilyl moiety (X-C6H4(CH3)2Si–) were analyzed by means of the Yukawa–Tsuno Equation. The X-phenyl-Si substituent effects (at 25 °C) were correlated against a set of X parameters of r+≅0.1 to give a [(ρX)Si] value of −1.06 for α-Ph (Y=H) and [(ρX)Si]=−1.18 for α-(m-CF3)phenyl (Y = m-CF3) subsets, which are all distinctly lower than that of −1.75 for the 2-[dimethyl(X-phenyl)silyl]ethyl solvolysis. The δY[(ρX)Si]Y can be regarded as the effect of the aryl substituents on the β-Si moiety on the benzylic cation center in the rate-determining step. The α-aryl substituent effect δY[log(kY)X=H] of 2-[dimethyl(X-phenyl)silyl]-1-(Y-phenyl)ethyl system was correlated against Y scale characteristic of the benzylic cation reactions (r+≅1.0) to give (ρY)α-Ar≅−3.0. The [(ρX)Si]Y values changed in parallel with the reactivities δY[log(kY)X=H] of the α-Ar substrate.
Synthesis and Photocleavage of 7-[{Bis(carboxymethyl)amino}coumarin-4-yl]methyl-Caged Neurotransmitters
Authors: Senda Naoko , Momotake Atsuya , Arai Tatsuo
Published: December 2007

7-[{Bis(carboxymethyl)amino}coumarin-4-yl]methyl-caged neurotransmitters (glutamate and GABA) were synthesized. Both caged compounds showed sufficient stability in the dark, were water-soluble at pH 7.2 without using organic solvents, and exhibited relatively high quantum yield for photolysis upon irradiation with 390 nm light.
Optical Resolution of Selenonium Imides Stabilized by an 8-Dimethylamino-1-naphthyl Group
Authors: Soma Takahiro , Kamigata Nobumasa , Hirabayashi Kazunori , Shimizu Toshio
Published: December 2007

Selenonium imides 1 and 2, stabilized by intramolecular coordination of the amino group of 8-dimethylamino-1-naphthyl substituent to the selenium atom, were synthesized. Optically active selenonium imides were obtained by chromatographic resolution on optically active columns and were found to be stable toward racemization both in the solid state and in solution. Absolute configurations of the optically active selenonium imides were assigned on the basis of specific rotations and circular dichroism spectra.
Rumphellatins B and C, Two New Caryophyllane-Type Hemiketal Norsesquiterpenoids from the Formosan Gorgonian Coral Rumphella antipathies
Authors: Sung Ping-Jyun , Chuang Li-Fan , Hu Wan-Ping
Published: December 2007

Two new caryophyllane-type hemiketal norsesquiterpenoid alcohols, designated as rumphellatins B (1) and C (2), were obtained from the Formosan gorgonian coral Rumphella antipathies. The structures of natural products 1 and 2 were established by analyzing the spectral data. Rumphellatin B (1) showed antibacterial activity toward the Gram-positive bacterium Staphylococcus aureus.
Synthesis of β,γ-Unsaturated Ketones from Acid Chlorides through Carbon–Pentamethylcyclopentadienyl Bond Formation and Cleavage
Authors: Uemura Minoru , Iwasaki Masayuki , Morita Eiji , Yorimitsu Hideki , Oshima Koichiro
Published: December 2007

Reaction of acid chlorides with lithium pentamethylcyclopentadienide afforded the corresponding pentamethylcyclopentadienyl ketones in high yield. These ketones were treated with an allylaluminum reagent to form the corresponding 3-butenyl alcohols. Removal of pentamethylcyclopentadiene upon heating or treatment with a catalytic amount of trichloroacetic acid yielded the corresponding β,γ-unsaturated ketones in good yields.
Diastereoselective Allylation of 3,4-Dihydro-4-phenylisoquinoline. Convenient Methods for the Preparation of cis- and trans-1-Allyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline
Authors: Taketoshi Ayako , Hosoda Naoya , Yamaguchi Yoshitaka , Asami Masatoshi
Published: December 2007

Diastereoselective allylation of 3,4-dihydro-4-phenylisoquinoline by several allylating reagents was examined. Reactions using allyltin or allylsilane in the presence of alkyl chloroformate and a catalytic amount of trimethylsilyl triflate gave trans-1-allyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline with moderate diastereoselectivity. In contrast, cis-1-allyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline was obtained predominantly in the reactions using allyllithium, triallylborane, allylzinc bromide, and diallylzinc. cis-1-Allyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline was transformed to (6S∗,10bR∗)-hexahydro-6-phenylpyrrolo[2,1-a]isoquinoline, a potential antidepressant agent, in five steps.
Novel Photoinduced Reduction of Conjugate Dienes by the Combination of Benzenethiol and Diphenyl Diselenide
Authors: Mitamura Takenori , Imanishi Yoshiaki , Nomoto Akihiro , Sonoda Motohiro , Ogawa Akiya
Published: December 2007

By using a binary system that consisted of benzenethiol and diphenyl diselenide under photoirradiation through a Pyrex vessel with a xenon lamp (λ>300 nm), a variety of conjugate dienes could be reduced to the corresponding internal alkenes under mild conditions.
Low Driving Voltage of Twisted Nematic Liquid Crystal Displays Doped with CdS Nanoparticles
Authors: Du Yukou , Toshima Naoki
Published: December 2007

CdS nanoparticles with size of 2.5±0.4 nm were prepared by using well-known reverse micelle methods. The CdS particles were characterized with ultraviolet and visible (UV–vis) absorption spectroscopy, transmission electron microscopy (TEM), energy-disperse X-ray analysis (EDX), Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). Twisted nematic liquid crystal display (TN-LCD) devices, doped with various amount of CdS nanoparticles, were studied for the first time. The results showed that electro-optic characteristics were featured by a frequency modulation. As the amount of dopant increased, a wider frequency response was achieved. Interestingly, the driving voltage of TN-LCD decreased as 4′-pentylbiphenyl-4-carbonitrile (4′-pentyl-4-cyanobiphenyl, 5CB) was doped with CdS nanoparticles.
Photoinduced Charge Separation of the Covalently Linked Fullerene–Triphenylamine–Fullerene Triad. Effect of Dual Fullerenes on Lifetimes of Charge-Separated States
Authors: El-Khouly Mohamed E , Kim Jong Hyung , Kwak Minseok , Choi Chan Soo , Ito Osamu , Kay Kwang-Yol
Published: December 2007

Photoinduced intramolecular events of the newly synthesized fullerene–triphenylamine–fullerene (C60–TPA–C60) triad, in which the TPA entity was substituted with an electron-donating CH3O-group to increase electron-donating ability, were investigated in relation to a C60–TPA dyad. The molecular orbital calculations showed that the radical cation is located on the TPA entity, whereas the radical anion is located on two C60 entities in the radical ion pair. The fluorescence intensity of the singlet excited state of C60 was efficiently quenched by the attached TPA moiety in polar solvents. The quenching pathway involves a charge-separation process from the TPA to the singlet excited state C60. The lifetimes of the radical ion-pairs for C60–TPA–C60 evaluated from nanosecond transient absorption measurements were found to be 600 and 454 ns in benzonitrile and dimethylformamide, respectively. These lifetimes of radical ion-pairs of C60–TPA–C60 are longer than those of the C60–TPA dyad, which reflects the effect of the second C60 moiety in stabilizing the radical ion-pairs.
A True Development Round? A Review of Joseph E. Stiglitz and Andrew Charlton's Fair Trade for All: How Trade Can Promote Development
Authors: Lawrence Robert Z
Published: December 2007

In Fair Trade for All: How Trade Can Promote Development, Stiglitz and Charlton prescribe what a multilateral trade agreement—that promotes development and is fair for all—would include. This review appraises their prescriptions and offers some alternatives. Many of their ideas about what developed countries should do (opening markets, especially of labor intensive goods and services and cutting farm subsidies) are quite familiar and sensible. More controversially, however, they propose that all WTO members (both developed and developing) completely open their markets to all developing countries poorer and smaller than themselves. They also stress the importance of preserving domestic policy space, dropping intellectual property rules from the WTO and keeping restrictive rules off the agenda. Among its criticisms of the book, the review points out that the liberalization proposal contradicts their own arguments favoring individually tailored policies in developing countries and is likely to maximize trade diversion. In addition, their prescriptions for more policy space neglects the more desirable possibility of a WTO in which members accept differentiated commitments.
Children in the Vanguard of the U.S. Welfare State: A Review of Janet Currie's The Invisible Safety Net and Jane Waldfogel's What Children Need
Authors: Smolensky Eugene
Published: December 2007

Policy driven social science research intended to influence the future of the U.S. welfare state has, during the past decade, emphasized improving the life-chances of children, particularly children disadvantaged at birth by the socioeconomic status of their parents. This essay samples that literature, discussing in detail the contents and implications of two recent largely synthetic volumes from this genre.
Do Cultural Differences Matter in Mergers and Acquisitions? A Tentative Model and Examination
Authors: Stahl Günter K. , Voigt Andreas
Published: December 2007

Asubstantive body of theory and research on the role of culture in mergers and acquisitions (M&A) suggests that cultural differences can create major obstacles to achieving integration benefits. However, the opposite view—that differences in culture between merging firms can be a source of value creation and learning—has also been advanced and empirically supported. In an attempt to reconcile these conflicting perspectives and findings, we present a model that synthesizes our current understanding of the role of culture in M&A, and we develop a set of hypotheses regarding mechanisms through which cultural differences affect M&A performance. The results of a meta-analysis of 46 studies, with a combined sample size of 10,710 M&A, suggest that cultural differences affect sociocultural integration, synergy realization, and shareholder value in different, and sometimes opposing, ways. Moderator analyses reveal that the effects of cultural differences vary depending on the degree of relatedness and the dimensions of cultural differences separating the merging firms, as well as on research design and sample characteristics. The implications for M&A research and practice are discussed.
Human Agents, Contexts, and Institutional Change: The Decline of Family in the Leadership of Business Groups
Authors: Chung Chi-Nien , Luo Xiaowei
Published: December 2007

This study examines the interaction between change-minded human agents and environmental and organizational contingencies to understand contested change in highly institutionalized practices. We propose a theory of how individuals, including those who are structurally highly embedded, can become change agents when confronted with amplified institutional contradictions. Using the empirical example of family presence in the leadership of Taiwanese business groups, we argue that despite the structural constraints on second-generation key leaders, these leaders are more likely to actualize their motivation to reduce family presence in the contexts of market-oriented transition and highly diversified business groups, and that key leaders with a management education from the United States are more likely to deviate from this institutionalized practice than are non-U.S.-educated key leaders, because they can transport ideas from different business models. A longitudinal analysis of the top 100 business groups in Taiwan between 1977 and 1998 largely supports our arguments. This study contributes to recent endeavors to understand antecedents to institutional change with an explicit focus on the interplay between agency and context, and to business-group research by examining the change of one foundational feature of the group form.
Academic Entrepreneurs: Organizational Change at the Individual Level
Authors: Bercovitz Janet , Feldman Maryann
Published: December 2007

This study explores the process of organizational change by examining localized social learning in organizational subunits. Specifically, we examine participation in university technology transfer, a new organizational initiative, by tracking 1,780 faculty members, examining their backgrounds and work environments, and following their engagement with academic entrepreneurship. We find that individual adoption of the new initiative may be either substantive or symbolic. Our results suggest that individual attributes, while important, are conditioned by the local work environment. In terms of personal attributes, individuals are more likely to participate if they trained at institutions that had accepted the new initiative and been active in technology transfer. In addition, we find that the longer the time that had elapsed since graduate training, the less likely the individual was to actively embrace the new commercialization norm. Considering the localized social environment, we find that when the chair of the department is active in technology transfer, other members of the department are also likely to participate, if only for symbolic reasons. We also find that technology transfer behavior is calibrated by the experience of those in the relevant cohort. If an individual can observe others with whom they identify engaging in the new initiative, then they are more likely to follow with substantive compliance. Finally, when individuals face dissonance, a situation where their individual training norms are not congruent with the localized social norms in their work environment, they will conform to the local norms, rather than adhering to the norms from their prior experience.
Dumb and Dumber: The Impact of Downsizing on Firm Performance as Moderated by Industry Conditions
Authors: Guthrie James P. , Datta Deepak K.
Published: December 2007

Workforce downsizing through employee layoffs has become commonplace in American businesses over the last 20 years. While these initiatives are typically undertaken in the quest for improved firm performance and competitiveness, empirical research to date has been equivocal in supporting the efficacy of these initiatives. In addition, extant research has not thoroughly examined factors or conditions that may influence or moderate the performance impact of workforce downsizing. In this paper, we address the question: Do industry conditions moderate the impact of workforce downsizing on firm performance? We examine this question using matched primary and secondary data on a sample of U.S. manufacturing firms. After controlling for a set of industry and firm-level variables, including firms' prior performance levels, our results indicate that downsizing is associated with decreases in subsequent firm profitability and that these negative effects are more pronounced in industries characterized by research and development (R&D) intensity, growth, and low capital intensity.
The ‘Burden’ of Domestic Rates
Authors: Nevitt Della Adam
Published: December 2007

Much criticism of rates has centred around the ‘burden’ of this tax – burden in the sense both of present weight of rates imposed and of the future burden which would have to be imposed if (a) local authority expenditure continues to rise as it has done in the past, and (b) central government grants are restricted to their present level of about sixty per cent of overall local authority expenditure. At present the domestic rate payer pays approximately half the amount raised through the local rate or twenty per cent of the total spent by local authorities. This amount varies from local authority to local authority as does the dependence on central government grants which represents only forty per cent of expenditure in some authorities but ninety per cent in the poorest.

The question of overall burden arises to some extent because the yield of rates is large and technically can be increased easily. The only tax yield which exceeds that obtained from the rates is the yield of direct taxes on incomes, and domestic rates share with these taxes the technical feature that they are inescapable and flexible.
The Creation of the Unemployment Assistance Board
Authors: Briggs Eric , Deacon Alan
Published: December 2007

The creation of the Unemployment Assistance Board in 1934 was an event of constitutional as well as political significance. The transfer of responsibility for the administration of unemployment assistance to a Board whose members were neither drawn from, nor directly answerable to Parliament raised important issues of ministerial responsibility and Parliamentary control. Consequently much of the literature upon the early operation of the Board has emphasised these constitutional aspects rather than the immediate reasons for its introduction. In particular few have challenged the explanation contained in J. D. Millet’s brilliant contemporary study, The Unemployment Assistance Board. Millet was primarily concerned with the Board’s relationship to Parliament. He argued that the transfer was essentially a Treasury measure, designed to halt the rise in the cost of unemployment relief by creating a buffer between the Government and the political pressures for more generous benefits. In short it was an attempt ‘to accomplish politically unpopular ends without suffering from the political consequences thereof’.

It is not the purpose of this article to deny the validity of Millet’s basic assertion. Certainly the aim of those involved in the planning of the Board was economy.
Ordering Change and Changing Orders: A Study of Urban Policy Development
Authors: Hart D. A.
Published: December 2007

Planning, it has been suggested, should serve as a framework for steering urban policy. The extent to which this prescriptive ideal has been realized in practice is a debatable point but it can be safely maintained that planning is becoming an increasingly important strand in the process of making policy at the urban level. One of the principal justifications for city planning is in fact that it aids policy-makers in their attempt to beneficially order urban development in a way which would simply not occur as a result of nondirected, random change. From this perspective planning derives much of its utility from the fact that it confers order on the city at various geographical levels by means of a concerted range of operating programmes. More accurately, it might be maintained that planning helps to assist in the long-term realisation in spatial and functional terms of a consciously ordered state of affairs for an urban area, while at the same time providing a parallel set of ‘ordered opportunities’ for the area’s inhabitants. Rarely however is either the central concept of order itself or the way in which it could be put into practice considered in any detail.