bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Evidence on the Links among Monetary Incentives, Task Attractiveness, and Task Performance
Authors: Fessler Nicholas J.
Published: April 2008

This study reports the results of a laboratory experiment where subjects performed a complex task under two types of compensation contracts, fixed-wage and piece-rate. Additionally, all subjects evaluated the attractiveness of the task prior to learning how they would be compensated during the experiment, and after they performed the experimental task under their assigned compensation contract. The results show that when the task was originally perceived as being attractive, piece-rate compensation led to a significant reduction in the perceived attractiveness of the task and worsened task performance relative to fixed-wage compensation. When the task was originally perceived as being unattractive, the form of compensation did not affect perceptions of task attractiveness or task performance. However, these results did not hold for a second group of subjects who performed a less complex task.
An Empirical Investigation of the Performance Consequences of Nonfinancial Measures
Authors: Said Amal A. , HassabElnaby Hassan R. , Wier Benson
Published: April 2008

Firms are increasingly implementing new performance measurement systems to track nonfinancial metrics such as customer and employee satisfaction, quality, market share, productivity, and innovation. This study examines the implications of nonfinancial performance measures included in compensation contracts on current and future performance. Contextual factors, environmental factors, and strategic plans vary across firms and, in turn, adopting appropriate nonfinancial measures determines the performance consequences of such measures. Our findings support the contention that firms that employ a combination of financial and nonfinancial performance measures have significantly higher mean levels of returns on assets and higher levels of market returns. Although we find evidence that the adoption of nonfinancial measures improves firms' current and future stock market performance, we find only partial support for accounting performance improvements. Overall, the results indicate that the association between the use of nonfinancial measures and firm performance is contingent on the firm's operational and competitive characteristics.
Complementarity, Task Assignment, and Incentives
Authors: Zhang Li
Published: April 2008

This paper studies the effect of complementarity on task assignment decisions and the design of optimal incentives for employees in charge of multiple tasks. A principal hires two identical agents. Each agent performs two tasks involving complementarities when the tasks vary in the informativeness of their performance measures. The principal tension governing how tasks are assigned lies between the heterogeneity loss due to aggregate performance measures under broad task assignments and the resulting positive information externalities. Although the aggregate performance measures under broad task assignments preclude tailoring the strength of incentives to the nature of the task, these measures are more informative about agent efforts when tasks are complementary. This enhanced informativeness improves contracting efficiency by mitigating the implicit costs of the heterogeneity loss. The analysis applies not only to the task assignment decisions, but also more broadly to other organizational structure decisions.
Budget-Based Contracts, Budget Levels, and Group Performance
Authors: Fisher Joseph G. , Peffer Sean A. , Sprinkle Geoffrey B.
Published: April 2008

In this paper, we experimentally investigate the effects of budget-based contracts and budget levels (performance targets) on group performance. We compare a group piece-rate contract with two different specifications of a group budget-based contract: (1) a group budget-fixed contract that provides no remuneration for performance below the budget and a fixed bonus for performance meeting or exceeding the budget, and (2) a group budget-linear contract that provides no remuneration for performance below the budget, a fixed bonus once the budget is attained, plus a piece-rate for production in excess of the budget. We also assigned each group a budget level, set at 50 percent, 75 percent, or 100 percent of the group's performance capability. The results indicate that the group budget-linear contract led to significantly higher group performance than both the group budget-fixed contract and the group piece-rate contract. Additionally, the 75 percent budget level led to significantly higher group performance than both the 50 percent budget level and the 100 percent budget level. Finally, the variability in group performance was lowest under the group budget-linear contract and the 75 percent budget level. Collectively, these results demonstrate the efficacy of both certain types of budget-based contracts and “moderately” difficult budget goals in enhancing group performance. The results also suggest that both motivation and coordination (planning) can be enhanced by budget levels of moderate difficulty and group budget-linear contracts, as the group budget-linear contract and the 75 percent budget level not only led to the highest level of performance, but also led to the lowest variability in performance.
Management Control Using Nonbinding Budgetary Announcements
Authors: Rankin Frederick W. , Schwartz Steven T. , Young Richard A.
Published: April 2008

We use an experiment to investigate the efficacy of a nonbinding budgetary announcement made by an owner in order to mitigate a management control problem induced by asymmetric information. The owner's announcement indicates how much funding she will provide for each possible cost report by the manager regarding an investment opportunity. The manager has private knowledge of the cost, incentive to overstate it, and the ability to do so undetected by the owner. The experiment consists of three treatments: (1) the owner fully commits to honor her announcement regarding how she will use the manager's cost report, (2) the owner makes no announcement at all, and (3) the owner makes a nonbinding announcement regarding how she will use the manager's cost report. The first two treatments establish empirical benchmarks to gauge the effectiveness of the nonbinding announcement. There are three main results. First, owners in the nonbinding announcement treatment significantly outperform those in the no-announcement treatment throughout the experiment. Second, owners appear to use the nonbinding announcement as a bluff in an attempt to convince managers that they will reject a profitable project more often than they intend. This strategy appears to be particularly effective for the owners in the first half of the experiment. Third, the difference in owner welfare between the nonbinding announcement and binding announcement treatments is much less than the prediction made from standard game-theoretic assumptions. The third result suggests that, to the extent that commitment is costly, an optimal control system might not employ commitment.
Cross-Sectional Field Studies in Management Accounting Research—Closing the Gaps between Surveys and Case Studies
Authors: Lillis Anne M. , Mundy Julia
Published: April 2008

While empirical researchers in management accounting frequently address overlapping research issues using a variety of methods, there is little evidence of productive dialogue addressing the uncertainties and ambiguities raised within each stream of research. For example, survey researchers frequently call for deeper field-based insights into conflicting or ambiguous findings. Case study researchers convey rich organizational stories of management accounting in context. However, these field-based findings are rarely used to resolve the ambiguity in construct definition, measurement, and inter-relationships that plague our empirical research bases. In this paper we seek to regenerate interest in a method that has been implemented in the past to promote productive field-based dialogue on issues related to complex constructs and their interrelationships. The method is best illustrated by the cross-sectional field study approach adopted by Merchant and Manzoni (1989) to study budget target achievability. By considering the Merchant and Manzoni (1989) study as well as two other examples (Bruns and McKinnon 1993; Abernethy and Lillis 1995) we identify the range of questions suited to this method and how the method contributes significant insights to the management accounting literature. We also articulate the design attributes of cross-sectional field studies by explicitly linking the rationale for these studies with the complexity of the phenomenon under study, sampling logic, instrument design, and data analysis protocols. The insights produced from the relatively few published studies using a cross-sectional field study method suggest that opportunities for the application of this method may be underexploited.
Cost Considerations in Optimal Capacity Acquisition: An Option Pricing Approach
Authors: Dhavale Dileep G.
Published: April 2008

The optimal capacity choice is a tradeoff between the costs of shortage and excess capacity. This paper models the costs as the prices of an infinite number of European call and put options maturing continuously over the planning horizon. This approach allows a firm to consider the benefits of flexibility arising from delaying the acquisition of some capacity to a later time when more information about stochastic demand becomes available. The firm can then adjust the capacity to meet exact demand by purchasing in the spot market or reselling in the salvage market. The model determines optimal capacity by minimizing acquisition and capacity adjustment costs. I compare the model to extant models and discuss some special situations. Qualitative sensitivity analysis describes the impact of changes in model parameters on the optimal capacity. A Monte Carlo simulation compares this model with other models and results show that the Option Pricing model results in the lowest operating cost for all scenarios considered. A substantially simplified version of the model, which does not require complete understanding of option pricing methods, also performs well under certain conditions.
Opportunity Costing Decision Heuristics for Product Acceptance Decisions
Authors: Leitch Robert A. , Philipoom Patrick R. , Fry Timothy D.
Published: April 2008

Full-cost heuristics have been proposed as proxies for opportunity costs in order acceptance decisions. We continue this investigation by considering the effect of different levels of stochastic product demand, lead-time allowances, variations in product cost structure, and the balance of workstation capacity, on the efficacy of the full-cost heuristic compared to other accounting based heuristics. We use simulation to consider a common job shop where order arrivals are stochastic and capacity acquisition takes place prior to demand realization. We find that the full-cost heuristic performs well when lead-time allowances are long and the shop is balanced. However, deviations from these conditions can lead to a reduction in its usefulness and better performance by other accounting heuristics.
Effects of Progesterone on Benzene Toxicity in Rats
Authors: Verma Yeshvandra , Rana Suresh
Published: April 2008

Effects of Progesterone on Benzene Toxicity in Rats

Benzene is a frequently used industrial solvent. Its toxic manifestations could be modified by sex hormones, but mechanisms of their action are poorly understood. We have examined the influence of progesterone on lipid peroxidation (malondialdehyde), reduced glutathione (GSH), and cytochrome P450 2E1 (CYP2E1) in the liver and kidneys of female rats. Progesterone applied to benzene-treated rats inhibited the formation of reactive oxygen species (ROS), but in ovariectomised benzene-treated rats it significantly increased GSH in the liver. No improvement in CYP2E1 activity was observed in progesterone treated rats. Our results evidence that progesterone changes benzene toxicity (generation of ROS, oxidative stress). However, the probable antioxidative effect of progesterone needs to be confirmed by further studies.
Non-Hip Peripheral Osteoporotic Fractures: Epidemiology and Significance
Authors: Koršić Mirko , Grazio Simeon
Published: April 2008

Non-Hip Peripheral Osteoporotic Fractures: Epidemiology and Significance

Fractures are the most serious consequence of osteoporosis. Non-vertebral and non-hip fractures are seldom recognised as important, even though they account for the majority of all fractures. The most prevalent localisations are distal radius, proximal humerus, ribs, clavicle, and the pelvis. According to the results from large phase III clinical trials for placebo groups, their incidence ranges from 4.9 % to 12.0 %. Hospital morbidity data in Croatia in 2006 show that peripheral non-hip fractures ranked among the leading fifteen injuries, accounting for 23.7 % of all injuries in patients aged 60 years and above. Risk factors for non-hip and non-vertebral fractures are similar to other osteoporotic fractures, and the main are low bone mineral density and earlier fractures. Quality of life is considerably affected by these fractures, and medical costs are very high, soaring as high as 36.9% of all national medical costs in the USA. Non-vertebral non-hip fractures need more attention, which was also recognised by the European regulatory bodies that approve use of anti-osteoporotic drugs.
Synthesis and pharmacological activities of some condensed 4-chloro-2,2-dialkyl chromene-3-carbaldehyde derivatives
Authors: Hegab Mohamed , Yousef Nabil , Nour Hany , Ellithey Mohey , Arbid Mahmoud
Published: April 2008

Synthesis and pharmacological activities of some condensed 4-chloro-2,2-dialkyl chromene-3-carbaldehyde derivatives

Some new hydrazono5a,b, thiosemicarbazono6a-c, and oximo chromenes7a-cwere preparedviathe reaction of the corresponding β-chlorocarbaldehyde3with hydrazine, aromatic hydrazine, thiosemicarbazide and hydroxylamine hydrochloride, respectively. In addition, ether derivatives8a-hwere prepared from the corresponding aldoximes7a-c. The new products were tested for anti-inflammatory and ulcerogenic score activities compared to indomethacin.
Synthesis of progesterone heterocyclic derivatives of potential antimicrobial activity
Authors: Mohareb Rafat , Hana Hanaa
Published: April 2008

Synthesis of progesterone heterocyclic derivatives of potential antimicrobial activity

The aim of this work was to synthesize steroidal heterocycles and to elucidate the potential role of these compounds as antimicrobial agents. The synthesis of steroidal heterocycles containing the pyrazole, isoxazole, thiazole, pyrane, pyridine, pyridazine, or benzopyrane ring attached to the pregnene nucleus is reported. Progesterone (1) reacts with dimethyl formamide dimethyl acetal to form enamine2. Heterocyclization of2with hydrazines, hydroxylamine, glycine, ethyl acetoacetate or cyanomethylene afforded novel steroidal heterocyclic derivatives. Thein vitroantimicrobial evaluation showed that all synthesized compounds show activity against the used strains of Gram positive bacteria and fungi.
New steroidal derivatives synthesized using 3β-hydroxyandrosten-17-one as starting material
Authors: Abd El-Latif Nehad , Abdulla Mohamed , Amr Abd
Published: April 2008

New steroidal derivatives synthesized using 3β-hydroxyandrosten-17-one as starting material

In this study, we synthesized some new substituted steroidal derivatives using 3β-hydroxyandrosten-17-one (dehydroepiandrosterone) as starting material. The synthesized steroidal derivatives1-11were evaluated for their androgenic-anabolic activities compared to testosterone as positive control. Details of the synthesis, spectroscopic data and toxicity (LD50) of synthesized compounds are reported.
Solid dispersion of meloxicam: Factorially designed dosage form for geriatric population
Authors: Pathak Deepa , Dahiya Sunita , Pathak Kamla
Published: April 2008

Solid dispersion of meloxicam: Factorially designed dosage form for geriatric population

The objective of the present work was to improve the dissolution properties of the poorly water-soluble drug meloxicam by preparing solid dispersions with hydroxyethyl cellulose (HEC), mannitol and polyethylene glycol (PEG) 4000 and to develop a dosage form for geriatric population. Differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy were used to investigate the solid-state physical structure of the prepared solid dispersions. Higher invitrodissolution of solid dispersions was recorded compared to their corresponding physical mixtures and the pure drug. PEG 4000 in 1: 9 drug to carrier ratio exhibited the highest drug release (100.2%), followed by mannitol (98.2%) and HEC (89.5%) in the same ratio. Meloxicam-PEG 4000 solid dispersion was formulated into suspension and optimization was carried out by 23factorial design. Formulations containing higher levels of methyl cellulose and higher levels of either sodium citrate or Tween 80 exhibited the highest drug release.
An Evaluation of the Working Income Tax Benefit
Authors: Scarth William , Tang Lei
Published: April 2008

The federal government has implemented an earned income tax creditwhat it has called the Working Income Tax Benefitin the 2007 Budget. Edmund Phelps argued that the earned income tax credit in the United States should be replaced with an employment subsidy. This paper assesses the importance of Phelps's concern, and related issues, for Canada. This debate is important for two reasons: the plight of those blocked by the “welfare wall” is dire, and the entire community has an interest in lower structural unemployment in an environment that involves an aging population and an accompanying labour shortage.
University Access Amid Tuition Fee Deregulation: Evidence from Ontario Professional Programs
Authors: Frenette Marc
Published: April 2008

Previous studies investigating university enrolment amid rising tuition fees have focused on undergraduate programs during the 1990s. Typically, little or no changes in enrolment patterns were observed, possibly because the fee increases were small in absolute terms and quite gradual. This study examines the impact of a very large and sudden deregulation of tuition fees in Ontario professional programs in the late 1990s. The findings suggest that enrolment patterns by socioeconomic background changed substantially in Ontario, where the deregulation of professional programs was most prominent. In Quebec and British Columbia, where fees remained stable, no change in enrolment patterns was registered.
Interactions between hydrology, burning and contrasting plant groups during the millennial‐scale development of sub‐montane wet heath
Authors: Ellis Christopher J.
Published: April 2008

Question:

How might contrasting plant groups interact to confer ecosystem stability during the development of a wet heath: i.e. in response to two major environmental drivers, past hydrologic change and burning?

Location:

Rannoch Moor, Scotland.

Methods:

Three peat cores were used to reconstruct vegetation change, surface moisture and burning phases, during wet heath development for a radiocarbon‐dated period from ca. 9500–1000 yr BP.

Results:

Statistical analysis of peat cores revealed significant relationships between burning phases and past periods of inferred surface dryness. Vegetation elements were related in the palaeoecological record to surface dryness (Ericaceae), wetness (Sphagnum, monocotyledons, and Racomitrium) and periods of burning (i.e. negative correlation of Racomitrium and monocotyledon remains with charcoal). However, correlations between plant groups could not be adequately explained by their equivalent direct response to hydrology and burning, and the effects of species interactions are invoked.

Conclusions:

The results indicate millennial‐scale stability of the wet heath ecosystem in response to past environmental change (i.e. hydrology and burning). This stability is conferred by interaction between a diversity of plant groups, enabling local shifts in vegetation composition in response to environmental drivers. This long‐term stability of the mire ecosystem forms a template against which present‐day threats (e.g. pollution, climate change) should be critically assessed.
Daily Supplementation with Iron Increases Lipid Peroxidation in Young Women with Low Iron Stores
Authors: King Sarah M. , Donangelo Carmen M. , Knutson Mitchell D. , Walter Patrick B. , Ames Bruce N. , Viteri Fernando E. , King Janet C.
Published: April 2008

The aim of this study was to determine whether women with low iron stores (plasma ferritin ≤ 20 μg/L) receiving a daily iron supplement for 8 wks at a level commonly used to treat poor iron status develop increased lipid peroxidation as measured by ethane exhalation rates and plasma malondialdehyde. The women served as their own control as pre- and post-supplementation periods were compared. Twelve women participated in the study for a 70-day period and consumed daily iron supplements (98 mg of iron as ferrous sulfate) from day 14 to day 70. Baseline blood and expired air samples were obtained on days 1 and 14; measurements during supplementation were performed on days 56 and 70, that is at 6 and 8 weeks of supplementation. Iron status improved during the iron supplementation period; biochemical indicators of lipid peroxidation also increased. After 6 wks of iron supplementation, serum ferritin almost doubled and body iron more than doubled. Hemoglobin levels increased slightly and other indicators of iron status became normal. However, plasma malondialdehyde (MDA) and breath ethane exhalation rates (BEER) increased by more than 40% between baseline and 6 wks of supplementation; these increases correlated significantly with plasma iron and ferritin levels. MDA was positively correlated with BEER. BEER increased further after 8 wks of iron supplementation. The increased indicators of lipid peroxidation with duration of supplementation and as iron status improved suggest that providing daily nearly 100 mg iron may not be a totally innocuous regimen for correcting iron depletion in women.
The Pig as an Experimental Model for Elucidating the Mechanisms Governing Dietary Influence on Mineral Absorption
Authors: Patterson Jannine K. , Lei Xin Gen , Miller Dennis D.
Published: April 2008

This review highlights the similarities between pigs and humans and thereby the value of the porcine human nutritional model, and reviews some of the more recent applications of this model for nutritional research.
Intermittent Hypoxia: Cause of or Therapy for Systemic Hypertension?
Authors: Serebrovskaya Tatiana V. , Manukhina Eugenia B. , Smith Michael L. , Downey H. Fred , Mallet Robert T.
Published: April 2008

During acute episodes of hypoxia, chemoreceptor-mediated sympathetic activity increases heart rate, cardiac output, peripheral resistance and systemic arterial pressure. However, different intermittent hypoxia paradigms produce remarkably divergent effects on systemic arterial pressure in the post-hypoxic steady state. The hypertensive effects of obstructive sleep apnea (OSA) vs. the depressor effects of therapeutic hypoxia exemplify this divergence. OSA, a condition afflicting 15–25% of American men and 5–10% of women, has been implicated in the pathogenesis of systemic hypertension and is a major risk factor for heart disease and stroke. OSA imposes a series of brief, intense episodes of hypoxia and hypercapnia, leading to persistent, maladaptive chemoreflex-mediated activation of the sympathetic nervous system which culminates in hypertension. Conversely, extensive evidence in animals and humans has shown controlled intermittent hypoxia conditioning programs to be safe, efficacious modalities for prevention and treatment of hypertension. This article reviews the pertinent literature in an attempt to reconcile the divergent effects of intermittent hypoxia therapy and obstructive sleep apnea on hypertension. Special emphasis is placed on research conducted in the nations of the former Soviet Union, where intermittent hypoxia conditioning programs are being applied therapeutically to treat hypertension in patients. Also reviewed is evidence regarding mechanisms of the pro- and anti-hypertensive effects of intermittent hypoxia.
Hypoxic Conditioning Suppresses Nitric Oxide Production upon Myocardial Reperfusion
Authors: Ryou Myoung-Gwi , Sun Jie , Oguayo Kevin N. , Manukhina Eugenia B. , Downey H. Fred , Mallet Robert T.
Published: April 2008

Physiologically modulated concentrations of nitric oxide (NO) are generally beneficial, but excessive NO can injure myocardium by producing cytotoxic peroxynitrite. Recently we reported that intermittent, normobaric hypoxia conditioning (IHC) produced robust cardioprotection against infarction and lethal arrhythmias in a canine model of coronary occlusion-reperfusion. This study tested the hypothesis that IHC suppresses myocardial nitric oxide synthase (NOS) activity and thereby dampens explosive, excessive NO formation upon reperfusion of occluded coronary arteries. Mongrel dogs were conditioned by a 20 d program of IHC (FIO2 9.5–10%; 5–10 min hypoxia/cycle, 5–8 cycles/d with intervening 4 min normoxia). One day later, ventricular myocardium was sampled for NOS activity assays, and immunoblot detection of the endothelial NOS isoform (eNOS). In separate experiments, myocardial nitrite (NO2−) release, an index of NO formation, was measured at baseline and during reperfusion following 1 h occlusion of the left anterior descending coronary artery (LAD). Values in IHC dogs were compared with respective values in non-conditioned, control dogs. IHC lowered left and right ventricular NOS activities by 60%, from 100–115 to 40–45 mU/g protein ( P < 0.01), and decreased eNOS content by 30% ( P < 0.05). IHC dampened cumulative NO2− release during the first 5 min reperfusion from 32 ± 7 to 14 ± 2 μmol/g ( P < 0.05), but did not alter hyperemic LAD flow (15 ± 2 vs. 13 ± 2 ml/g). Thus, IHC suppressed myocardial NOS activity, eNOS content, and excessive NO formation upon reperfusion without compromising reactive hyperemia. Attenuation of the NOS/NO system may contribute to IHC-induced protection of myocardium from ischemia-reperfusion injury.
Effect of Buddleja officinalis on High-Glucose-Induced Vascular Inflammation in Human Umbilical Vein Endothelial Cells
Authors: Lee Yun Jung , Kang Dae Gill , Kim Jin Sook , Lee Ho Sub
Published: April 2008

In this study, we aimed to investigate whether an aqueous extract of Buddleja officinalis (ABO) suppresses high-glucose-induced vascular inflammatory processes in the primary cultured human umbilical vein endothelial cells (HUVEC). The high-glucose-induced increase in expression of cell adhesion molecules (CAMs) such as intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial-selectin (E-selectin) was significantly attenuated by pretreatment with ABO in a dose-dependent manner. Enhanced cell adhesion caused by high glucose in co-cultured U937 and HUVEC was also blocked by pretreatment with ABO. Pretreatment with ABO also blocked formation of high-glucose-induced reactive oxygen species (ROS). In addition, ABO suppressed the transcriptional activity of NF-κB and IκB phosphorylation under high-glucose conditions. Pretreatment with N(G)-nitro-l-arginine methyl ester (L-NAME), an endothelial nitric oxide (NO) synthase inhibitor, attenuated the protective action of ABO on high-glucose-induced CAM expression, suggesting a potential role of NO signaling. The present data suggest that ABO could suppress high-glucose-induced vascular inflammatory processes, and ABO may be closely related with the inhibition of ROS and NF-κB activation in HUVEC.
Generation of Mature Dendritic Cells with Unique Phenotype and Function byIn VitroShort-Term Culture of Human Monocytes in the Presence of Interleukin-4 and Interferon-β
Authors: Zhang Li Feng , Okuma Kazu , Tanaka Reiko , Kodama Akira , Kondo Kayo , Ansari Aftab A. , Tanaka Yuetsu
Published: April 2008

Dendritic cell (DC)-based immunotherapy has been utilized for the treatment of not only a number of human malignancies but also a select group of infectious diseases. Conventional techniques for the generation and maturation of DCs require 7 days of in vitro culture, which prompted us to seek alternative methods that would hasten the generation of functional human myeloid DCs in vitro. Following the use of a number of cytokines/growth factors, we found that in vitro culture of purified human monocytes, in media containing interleukin (IL)-4, together with interferon (IFN)-β for 24 hrs, followed by the addition of non-specific antigenic stimuli, such as keyhole limpet hemocyanin (KLH), lipopolysaccharide (LPS), or inactivated human immunodeficiency virus (HIV)-1 induced the monocytes to differentiated by 3 days into mature DCs (4B-DCs). These 4B-DCs expressed high levels of CD83 and CD11c, as well as markers of immune activation, including CD80 and CD86, human leukocyte antigen (HLA) class I and II, and CD14, but not CD1a. Anti-CD14 blocking antibody interfered with generation of 4B-DCs by LPS, but not by KLH or HIV-1. Interestingly, 4B-DCs, but not conventional DCs generated using macrophage-colony stimulating factor and IL-4 (G4-DCs), expressed OX40 and OX40L. 4B-DCs showed phagocytic activity, and spontaneously produced IL-12 and tumor necrosis factor (TNF)-α, but not IL-10. 4B-DCs promoted proliferation of allogeneic naïve CD4+T cells, producing IFN-λat lower levels than those stimulated with G4-DCs. 4B-DCs were more potent stimulators of allogeneic bulk CD8+T cells producing IFN-λthan G4-DCs. These data indicate that 4B-DCs are unique and may provide a relatively more rapid alternative tool for potential clinical use, as compared with conventional G4-DCs.
Coordinated Upregulation of a Series of Endogenous Antioxidants and Phase 2 Enzymes as a Novel Strategy for Protecting Renal Tubular Cells from Oxidative and Electrophilic Stress
Authors: Zhu Hong , Zhang Li , Amin Ashok R. , Li Yunbo
Published: April 2008

In view of the crucial involvement of oxidative and electrophilic stress in various kidney disorders, this study was undertaken to test the hypothesis that pharmacologically-mediated coordinated upregulation of endogenous renal antioxidants and phase 2 enzymes is an effective strategy for renal protection. Notably, studies on the pharmacological inducibility of a series of antioxidants and phase 2 enzymes in renal tubular cells are lacking. Here we reported that incubation of normal rat kidney (NRK-52E) proximal tubular cells with low micromolar concentrations (10–50 μM) of the cruciferous nutraceutical, 1,2-dithiole-3-thione (D3T), led to a significant concentration-dependent induction of a wide spectrum of antioxidants and phase 2 enzymes, including catalase (CAT), reduced form of glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), NAD(P)H:quinone oxidoreductase 1 (NQO1), and heme oxygenase (HO). We further observed that D3T treatment also increased the protein and mRNA expression for CAT, γ-glutamylcysteine ligase, GR, GST-A, GST-M, NQO1, and HO-1. Incubation of the renal tubular cells with H2O2, SIN-1-derived peroxynitrite, or 4-hydroxy-2-nonenal led to concentration-dependent decreases in cell viability. Pretreatment of the renal tubular cells with 10–50 μM D3T afforded remarkable protection against the nephrocytotoxicity elicited by the above oxidative and electrophilic species. The D3T-mediated cytoprotection showed a concentration-dependent relationship. Taken together, this study for the first time comprehensively characterized the inducibility by a unique nutraceutical of a wide spectrum of antioxidative and phase 2 defenses in renal tubular cells at the levels of enzyme activity as well as protein and mRNA expression, and demonstrated that such a coordinated upregulation of cellular defenses led to remarkable protection of renal tubular cell from oxidative and electrophilic stress. Because of the crucial role of oxidative and electrophilic stress in inflammatory injury, D3T-mediated coordinated induction of endogenous antioxidative and phase 2 defenses may also serve as an important anti-inflammatory mechanism in kidneys.
Touch Study of Polymer Materials Surfaces — Description of Raspiness by a Correlation Approach Between Sensorial Analysis and Physical Measurements
Authors: Sabiri N. , Leblond L. , Villoutreix J. , Lavergne M. , Acétarin J.‐D. , Villoutreix G.
Published: April 2008

To the various criteria such as durability and comfort, always taken into account for the purchase of a vehicle, nowadays criteria of sensory size like smell and touch are to be added. We carried out this study on evaluation of touch and more particularly on touch of plastics surfaces as these materials are largely used in automobile cockpits (handles of door, seats, dashboards). The touch of these materials must first be evaluated in order to be controlled. It is the role of the panels of skilled experts, who use various tactile descriptors to characterize surfaces according to human sensitivity. The objective of this work is to undergo a statistical analysis of tactile data on the basis of precise criteria (repeatability, consistency, precision of analysis) in order to achieve a characteristic model of a given descriptor, selected for the tactile sensory analysis. In parallel, with the analysis of the panel data, we tried to characterize the surface of samples by instrumental physical measurements. A second part of this work will lead us, in the framework of the study of roughness, to try to establish a correlation between these measurements and the data obtained according to the protocol of the raspy descriptor of sensory analysis.
Influence of Laser‐Induced Topography Changes on the Activity of Catalyst Coatings as Examined by Infrared Thermography
Authors: Seyler Michael , Selzner Christian , Holzapfel Christian , Mücklich Frank , Maier Wilhelm F.
Published: April 2008

A mixed metal oxide catalyst coating is subjected to laser irradiation by a Nd:YAG laser operating at 266 nm to induce local changes in surface topography. The coating is exposed to laser interference patterns as well as to direct laser irradiation without interference. Samples are characterized by means of White Light Interferometry and Scanning Electron Microscopy. Irradiation with interference patterns causes the formation of wave‐like surface patterns in micrometer scale whereas direct laser irradiation generates porosity with pore sizes in the range of 100nm. Emissivity‐corrected infrared thermography (ecIRT) is applied to analyze the effect of surface topography changes on the catalytic activity of coatings in parallel. The catalytic combustion of iso‐octane with different contents of oxygen in nitrogen is used as a test reaction for catalytic activity. Local temperature increase on the substrate is chosen as a measure for catalytic activity. For laser interference structured coating, the catalytic activity improves with increase in geometric surface area caused by the wave‐like pattern. For direct laser irradiation, the porosity created by the laser enhances catalytic activity with respect to the unstructured coating.
Fabrication of a Memory Chip by a Complete Self‐Assembly Process Using State‐of‐the‐Art Multilevel Cell (MLC) Technology
Authors: Bandyopadhyay Anirban , Miki Kazushi
Published: April 2008

Using a two bit molecular switch, an ultra‐dense memory chip has been built following a fully automated fabrication process. Well‐ordered templates are grown naturally using a well‐defined protocol of temperature variation. This template is so designed that molecules are adsorbed selectively only into particular sites whenever they are bombarded on the template through an e‐beam evaporator for a particular time. The technique is a generalized protocol that has been used to grow atomic‐scale templates by proper tuning of basic global parameters like temperature and evaporation time. Tuning of the basic template parameters is also demonstrated here, and has been used to scale down parameter values following the same route. Tuning the junction profile should allow selective adsorption of more complicated multi‐level switches in future. Therefore, a fairly simple technology has been established that addresses one of the most fundamental issues of continuous miniaturization, i.e., simultaneous automated growth of thousands of atomically precise single molecular devices.
Poly(vinyl alcohol) Rehydratable Photonic Crystal Sensor Materials
Authors: Muscatello Michelle M. Ward , Asher Sanford A.
Published: April 2008

We developed a new photonic crystal hydrogel material based on the biocompatible polymer poly (vinyl alcohol) (PVA), which can be reversibly dehydrated and rehydrated, without the use of additional fillers, while retaining the diffraction and swelling properties of polymerized crystalline colloidal arrays (PCCA). This chemically modified PVA hydrogel photonic crystal efficiently diffracts light from the embedded crystalline colloidal array. This diffraction optically reports on volume changes occurring in the hydrogel by shifts in the wavelength of the diffracted light. We fabricated a pH sensor, which demonstrates a 350 nm wavelength shift between pH values of 3.3 and 8.5. We have also fabricated a Pb+2 sensor, in which pendant crown ether groups bind lead ions. Immobilization of the ions within the hydrogel increases the osmotic pressure due to the formation of a Donnan potential, swelling the hydrogel and shifting the observed diffraction in proportion to the concentration of bound ions. The sensing responses of rehydrated PVA pH and Pb+2 sensors were similar to that before drying. This reversibility of rehydration enables storage of these hydrogel photonic crystal sensors in the dry state, which makes them much more useful for commercial applications.
Mechanistic Inferences Derived from Competitive Catalytic Reactions: Pd(binap)‐Catalyzed Amination of Aryl Halides
Authors: Ferretti Antonio C. , Mathew Jinu S. , Ashworth Ian , Purdy Malcolm , Brennan Colin , Blackmond Donna G.
Published: April 2008

Healthy competition: The Pd(binap)‐catalyzed amination of aryl halides demonstrates how the results from competitive reactions can be strikingly different from those obtained from study of the separate reactions. We show how the competitive network provides mechanistic information not accessible from study of the reactions separately.
Diastereoselective Synthesis of Trifluoromethylated γ‐Butyrolactones via N‐Heterocyclic Carbene‐Catalyzed Conjugated Umpolung of α,β‐Unsaturated Aldehydes
Authors: Hirano Keiichi , Piel Isabel , Glorius Frank
Published: April 2008

The N‐heterocyclic carbene‐catalyzed conjugate umpolung of differently substituted α,β‐unsaturated aldehydes is described. Coupling of these compounds with a variety of trifluoromethylated ketones results in the selective formation of fluorinated γ‐butyrolactones. Using thiazolium‐derived N‐heterocyclic carbenes, the unlike stereoisomers are formed predominantly, whereas the imidazol‐2‐ylidene IMes results in lower selectivities and the preferred formation of the like isomer.
Enantioselective Organocatalytic Epoxidation Driven by Electrochemically Generated Percarbonate and Persulfate
Authors: Page Philip C. Bulman , Marken Frank , Williamson Craig , Chan Yohan , Buckley Benjamin R. , Bethell Donald
Published: April 2008

An organocatalytic asymmetric epoxidation reaction using iminium salt catalysts is described, in which the stoichiometric persulfate oxidant is generated electrochemically. This system offers comparable ees to the use of commercially available persulfate. Electrochemically generated percarbonate ion is also a successful and novel oxidant system for use with iminium salts.
Bakterielle Acyltransferasen als Alternative für lipasekatalysierte Acylierungen zur Produktion von Oleochemikalien und Brennstoffen
Authors: Stöveken Tim , Steinbüchel Alexander
Published: April 2008

Bakterielle Acyltransferasen bilden eine neue Enzymklasse, als deren erstes Mitglied die WS/DGAT in Acinetobacter baylyi ADP1 identifiziert wurde. Ihre geringe Spezifität wurde für zahlreiche biotechnologische Anwendungen zur Lipidmodifizierung genutzt, ein Gebiet, auf dem bisher hauptsächlich Lipasen Verwendung finden. Beispiele sind die Biosynthesen von Jojoba‐ähnlichen Wachsestern und von Fettsäureethylestern. Darüber hinaus lassen sich mit diesen Enzymen Acylthioester synthetisieren. Acyltransferasen sind eine mögliche Alternative zu Lipasen. Mit ihnen können Acyloxoester und Acylthioester statt durch In‐vitro‐Katalyse im Enzymreaktor in vivo durch Ganzzellkatalyse hergestellt werden. In diesem Kurzaufsatz beleuchten wir die biotechnologische Verwendung der Acyltransferasen für die Produktion von modifizierten Lipiden, ausgehend von erneuerbaren Rohstoffen.
Bacterial Acyltransferases as an Alternative for Lipase‐Catalyzed Acylation for the Production of Oleochemicals and Fuels
Authors: Stöveken Tim , Steinbüchel Alexander
Published: April 2008

Bacterial acyltransferases are a new class of enzymes, and the first member was identified as WS/DGAT in Acinetobacter baylyi ADP1. Their unspecificity have been used in several biotechnological applications for lipid modification, a field that has been dominated by the use of lipases. Examples are the biosynthesis of jojoba‐like wax esters and fatty‐acid ethyl esters. In addition, these enzymes are also capable of synthesizing acylthioesters. Acyloxoesters and acylthioesters can thus be produced in vivo by whole‐cell fermentations rather than in vitro in an enzyme reactor. In this Minireview, we focus on the biotechnological utilization of acyltransferases for the production of modified lipids from renewable resources.
A Ruthenium Bridge in Fullerene–Ferrocene Arrays: Synthesis of [Ru(C60Me5)R(CO)2] (R=C6H4Fc, C≡CFc) and Their Charge‐Transfer Properties
Authors: Matsuo Yutaka , Matsuo Keiko , Nanao Takeshi , Marczak Renata , Gayathri S. Shankara , Guldi Dirk M. , Nakamura Eiichi
Published: April 2008

New fullerene–ferrocene arrays, [Ru(C60Me5)(C4H6Fc)(CO)2] (Fc=ferrocenyl) and [Ru(C60Me5)(CCFc)(CO)2], in which the ruthenium complex functions as a conjugative bridge, were synthesized by the reaction of [Ru(C60Me5)Cl(CO)2] with FcC6H4MgBr and FcCCLi, respectively. These compounds were investigated by electrochemical measurement, single‐crystal X‐ray structural analysis, and photophysical measurement. Upon photoirradiation, the former compound was converted rapidly into the corresponding triplet state in toluene (τsinglet=21 ps), whereas the charge‐separated state was predominant in THF (τsinglet=10.5 ps; τCS=355 ps). The latter compound, on the other hand, formed the charge‐separated state in both toluene and THF (τsinglet=3.0 ps; τCS=152 ps). Thus, the structural difference between the phenylene and acetylene bridges in 1 and 2, respectively, was found to change the outcome of the photophysical processes.
Tailored Control and Optimisation of the Number of Phosphonic Acid Termini on Phosphorus‐Containing Dendrimers for the Ex‐Vivo Activation of Human Monocytes
Authors: Rolland Olivier , Griffe Laurent , Poupot Mary , Maraval Alexandrine , Ouali Armelle , Coppel Yannick , Fournié Jean‐Jacques , Bacquet Gérard , Turrin Cédric‐Olivier , Caminade Anne‐Marie , Majoral Jean‐Pierre , Poupot Rémy
Published: April 2008

The syntheses of a series of phosphonic acid‐capped dendrimers is described. This collection is based on a unique set of dendritic structural parameters—cyclo(triphosphazene) core, benzylhydrazone branches and phosphonic acid surface—and was designed to study the influence of phosphonate (phosphonic acid) surface loading towards the activation of human monocytes ex vivo. Starting from the versatile hexachloro‐cyclo(triphosphazene) N3P3Cl6, six first‐generation dendrimers were obtained, bearing one to six full branches, that lead to 4, 8, 12, 16, 20 and 24 phosphonate termini, respectively. The surface loading was also explored at the limit of dense packing by means of a first‐generation dendrimer having a cyclo(tetraphosphazene) core and bearing 32 termini, and with a first‐generation dendrimer based on a AB2/CD5 growing pattern and bearing 60 termini. Human monocyte activation by these dendrimers confirms the requirement of the whole dendritic structure for bioactivity and identifies the dendrimer bearing four branches, thus 16 phosphonate termini, as the most bioactive.
Estimating the Temperature Dependence of Peptide Folding Entropies and Free Enthalpies from Total Energies in Molecular Dynamics Simulations
Authors: Boned Ricard , van Gunsteren Wilfred F. , Daura Xavier
Published: April 2008

The temperature dependence of thermodynamic quantities, such as heat capacity, entropy and free enthalpy, may be obtained by using well‐known equations that relate these quantities to the enthalpy of the molecular system of interest at a range of temperatures. In turn, the enthalpy of a molecular system can be estimated from molecular dynamics simulations of an appropriate model. To demonstrate this, we have investigated the temperature dependence of the enthalpy, heat capacity, entropy and free enthalpy of a system that consists of a β‐heptapeptide in methanol and have used the statistical mechanics relationships to describe the thermodynamics of the folding/unfolding equilibrium of the peptide. The results illustrate the power of current molecular simulation force fields and techniques in establishing the link between thermodynamic quantities and conformational distributions.
Tandem Cofacial Stacks of Porphyrin–Phthalocyanine Dyads through Complementary Coordination
Authors: Morisue Mitsuhiko , Kobuke Yoshiaki
Published: April 2008

A novel straightforward methodology to organize discrete heterogeneous stacks of porphyrin and phthalocyanine employed an imidazolyl‐to‐zinc complementary coordination protocol for a ZnIIphthalocyanine that contains an imidazolyl terminal with an ethynylporphyrin as a coplanar spacer. Structural elucidation was performed by means of size‐exclusion chromatography, spectral titration, and NMR spectroscopy. The association constants for the complementary coordination of the heterogeneous slipped‐cofacial tetrads reached extremely high values, in the order of 1014 M−1. Close contact of the porphyrin and phthalocyanine planes led to a strong shielding of the cofacial protons, which were split due to the slipped‐cofacial heterogeneous environment. In variable‐temperature NMR spectroscopy, the split signals remained in the aromatic region, a result suggesting structural robustness. Addition of trifluoroacetic acid dissociated the coordination structure to unify the split signals. The stacked tetrads showed unique electronic structures, such as strong exciton coupling and charge‐transfer properties between the porphyrin and phthalocyanine units, which were modulated by the peripheral substituents of the phthalocyanine subunit and by the solvent. Interconversion between the coordination tetrad and the corresponding dyad was observed upon addition of an axial ligand.