bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential expression of leukocyte immunoglobulin-like receptors on cord blood-derived human mast cell progenitors and mature mast cells
Authors: Tedla Nicodemus , Lee Chyh-Woei , Borges Luis , Geczy Carolyn L , Arm Jonathan P
Published: November 2007

The leukocyte Ig-like receptors (LILRs) comprise a family of cell-surface immunoregulatory receptors with activating and inhibitory members. The inhibitory LILRs possess cytoplasmic ITIMs that down-regulate signaling by nonreceptor tyrosine kinase cascades. The activating members have a truncated cytoplasmic domain and signal through the FcRγ chain. We examined the expression of LILRs on human mast cells during their development in vitro. Progenitor mast cells expressed cell surface inhibitory LILRB1, -B2, -B3, and -B4 and activating LILRA1. However, although mature cord blood-derived mast cells (hMCs) had detectable mRNA encoding multiple LILRs, none were expressed on the cell surface. Culture of progenitor mast cells or hMCs with various cytokine combinations failed to retain or induce cell surface expression of the LILRs. It is interesting that hMCs expressed LILRB5 in cytoplasmic granules and upon cross-linking of the high-affinity IgE receptor, released LILRB5 into the culture medium. Our results demonstrate that LILRs are developmentally regulated in human mast cells and that LILRB5 is expressed in mast cell granules and the release of soluble LILRB5 following IgE FcR-dependent stimulation, which has potential for amplification of mast cell-dependent, inflammatory responses.
Dendritic cells at the interface of innate and acquired immunity: the role for epigenetic changes
Authors: Wen Haitao , Schaller Matthew A , Dou Yali , Hogaboam Cory M , Kunkel Steven L
Published: November 2007

Dendritic cells (DC) are known to be essential immune cells in innate immunity and in the initiation of adaptive immunity. The shaping of adaptive immunity by innate immunity is dependent on DC unique cellular functions and DC-derived effector molecules such as cytokines and chemokines. Thus, it is not surprising that numerous studies have identified alterations in DC number, function, and subset ratios in various diseases, such as infections, cancers, and autoimmune diseases. Recent evidence has also identified that immunosuppression occurring after severe systemic inflammation, such as found in sepsis, is a result of depletion in DC numbers and a later dysfunction in DC activity. This correlation suggests that the sustained DC dysfunction initiated by life-threatening inflammation may contribute to the subsequent immunoparalysis, potentially as a result of the long-term maintenance of an abnormal gene expression pattern. In this review, we summarized the present information regarding altered DC function after a severe, acute inflammatory response and propose a mechanism, whereby epigenetic changes can influence long-term gene expression patterns by DC, thus supporting an immunosuppression phenotype.
Role of preprotachykinin-A gene products on multiple organ injury in LPS-induced endotoxemia
Authors: Ng Siaw Wei , Zhang Huili , Hegde Akhil , Bhatia Madhav
Published: November 2007

Endotoxemia is a life-threatening, inflammatory condition that involves multiple organ injury and dysfunction. Preprotachykinin-A (PPT-A) gene products, substance P (SP), and neurokinin-A have been shown to play an important role in neurogenic inflammation. To investigate the role of PPT-A gene products on multiple organ injury in LPS-induced endotoxemia, endotoxemia was induced by LPS administration (10 mg/kg, i.p.) in PPT-A gene-deficient mice (PPTA−/−) and the wild-type (WT) control mice (PPT-A+/+). I.p. administration of LPS to WT mice caused a significant increase in circulating levels of SP as well as in liver, lung, and kidney. PPT-A gene deletion significantly protected against liver, pulmonary, and renal injury following LPS-induced endotoxemia, as evidenced by tissue myeloperoxidase activities, plasma alanine aminotransferase, aspartate aminotransferase levels, and histological examination. Furthermore, PPT-A−/− mice had significantly attenuated chemokines, proinflammatory cytokines, and adhesion molecule levels in the liver, lung, and kidney. These results show that PPT-A gene products are critical proinflammatory mediators in endotoxemia and the associated multiple organ injury. In addition, the data suggest that deletion of the PPT-A gene protected mice against organ damage in endotoxemia by disruption in neutrophil recruitment.
Issues and Challenges With Integrating Patient-Reported Outcomes in Clinical Trials Supported by the National Cancer Institute–Sponsored Clinical Trials Networks
Authors: Watkins Bruner Deborah , Bryan Charlene J. , Aaronson Neil , Blackmore C. Craig , Brundage Michael , Cella David , Ganz Patricia A. , Gotay Carolyn , Hinds Pamela S. , Kornblith Alice B. , Movsas Benjamin , Sloan Jeff , Wenzel Lari , Whalen Giles
Published: November 2007

Purpose

The objective of this report is to provide a historical overview of and the issues and challenges inherent in the incorporation of patient-reported outcomes (PROs) into multinational cancer clinical trials in the cancer cooperative groups.

Methods

An online survey of 12 cancer cooperative groups from the United States, Canada, and Europe was conducted between June and August of 2006. Each of the cooperative groups designated one respondent, who was a member of one of the PRO committees within the cooperative group.

Results

There was a 100% response rate, and all of the cancer clinical trial cooperative groups reported conducting PRO research. PRO research has been conducted in the cancer cooperative groups for an average of 15 years (range, 6 to 30 years), and all groups had multidisciplinary committees focused on the design of PRO end points and the choice of appropriate PRO measures for cancer clinical trials. The cooperative groups reported that 5% to 50% of cancer treatment trials and an estimated 50% to 75% of cancer control trials contained PRO primary and secondary end points. There was considerable heterogeneity among the cooperative groups with respect to the formal and informal policies and procedures or cooperative group culture towards PROs, investigator training/mentorship, and resource availability for the measurement and conduct of PRO research within the individual cooperatives.

Conclusion

The challenges faced by the cooperative groups to the incorporation of PROs into cancer clinical trials are varied. Some common opportunities for improvement include the adoption of standardized training/mentorship mechanisms for investigators for the conduct of PRO assessments and data collection and the development of minimal criteria for PRO measure acceptability. A positive cultural shift has occurred in most of the cooperative groups related to the incorporation of PROs in clinical trials; however, financial and other resource barriers remain and need to be addressed.
Lessons Learned in the Assessment of Health-Related Quality of Life: Selected Examples From the National Cancer Institute of Canada Clinical Trials Group
Authors: Brundage Michael , Osoba David , Bezjak Andrea , Tu Dongsheng , Palmer Michael , Pater Joseph
Published: November 2007

In this article, we provide a brief historical review of the development of patient-reported outcome measurement, analysis, and reporting in clinical trials of the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG). In doing so, we examine selected lessons learned in furthering the quality of these data and their application to clinical practice. We conclude that sequential institution of key policies within the NCIC CTG and the development of a collective philosophy within the group has enabled the routine incorporation of health-related quality of life into clinical trial protocols according to robust scientific principles; that collection of quality data is possible in a variety of circumstances (although not universally so); that patient-reported data on subjective experiences is likely to be more reliable and valid than conventional toxicity information; and that simple analyses that report group trends as well as individual patient response rates are preferred.
Compliance With Patient-Reported Outcomes in Multicenter Clinical Trials: Methodologic and Practical Approaches
Authors: Land Stephanie R. , Ritter Marcie W. , Costantino Joseph P. , Julian Thomas B. , Cronin Walter M. , Haile Sarah R. , Wolmark Norman , Ganz Patricia A.
Published: November 2007

Purpose

This report describes interventions undertaken by the National Surgical Adjuvant Breast and Bowel Project (NSABP) to improve compliance with patient-reported outcome (PRO) assessments in the setting of multicenter cancer clinical trials. We describe the effectiveness of several interventions and of observational factors.

Methods

PRO submission rates were analyzed for the following three NSABP protocols: the Study of Raloxifene and Tamoxifen (STAR), B-32, and B-35. Institutions participating in protocol B-35 were randomly assigned to receive automated reminders of upcoming assessments or not. Compliance was analyzed with a logistic repeated measures mixed modeling.

Results

Compliance was high in the three protocols, with rates greater than 80% for nearly all time points. Institutions were a significant source of variability (P < .01). The largest institutions had the highest compliance in STAR (odds ratio [OR] = 0.68 for < 50 participants enrolled and OR = 0.82 for 50 to 99 participants enrolled v larger institutions; P < .001). Midsized institutions had highest compliance in B-32 (OR = 4.63 for 31 to 50 patients enrolled and OR = 3.12 for > 50 patients enrolled v small institutions; P = .007). Compliance increased with participant age in STAR (OR = 0.57, 0.89, and 1.01 for ages < 50, 50 to 60, and 60 to 70 years, respectively, v > 70 years; P < .001). Race was significant in B-32 (OR = 2.63 for white v nonwhite; P < .001) and in STAR (OR = 1.41 for white v nonwhite; P < .001). Treatment group was significant in B-32 (OR = 0.74; P = .006). The B-35 prospective reminder did not improve compliance significantly (P = .30), but in B-32, delinquency sanctions were significant (OR = 1.56; P = .007).

Conclusion

Compliance in NSABP PRO studies is higher now than a decade ago. Results for compliance initiatives were mixed. Age and race are important factors, but institutional variation remains significant and largely unexplained.
Familial Chronic Myeloproliferative Disorders: Clinical Phenotype and Evidence of Disease Anticipation
Authors: Rumi Elisa , Passamonti Francesco , Della Porta Matteo G. , Elena Chiara , Arcaini Luca , Vanelli Laura , Del Curto Cecilia , Pietra Daniela , Boveri Emanuela , Pascutto Cristiana , Cazzola Mario , Lazzarino Mario
Published: November 2007

Purpose

Chronic myeloproliferative disorders (CMDs) have sporadic occurrence. However, familial clustering is reported. The purpose of this study was to assess the prevalence and the clinical phenotype of familial CMDs, and to study the anticipation of disease onset in successive generations.

Patients and Methods

Among 458 patients with apparently sporadic CMDs, an interview-based investigation of family history was performed to identify familial cases. The clinical phenotype of familial CMDs was compared with that of sporadic CMDs. Anticipation was studied evaluating age at diagnosis and telomere length in successive generations.

Results

Among 458 patients with apparently sporadic CMDs, the prevalence of familial cases was 7.6% (35 pedigrees; 75 patients). Kolmogorov-Smirnov and two-tailed Fisher's exact tests did not demonstrate significant differences in clinical presentation between patients with familial and sporadic CMDs. Within 544 person-years of follow-up, patients with familial CMDs developed similar complications and disease evolutions as those with sporadic CMDs. The comparison of second-generation and first-generation patients showed a significantly younger age at diagnosis (Wilcoxon matched-pair test, P = .001) and a significantly higher age-dependent hazard of CMD onset (Nelson-Aalen method, P < .001) in patients of the second generation. A significant shortening of telomere length was highlighted in offspring compared with parent (P = .043).

Conclusion

This study indicates that a thorough investigation of family history should be part of the initial work-up of patients with CMDs. Patients with familial CMDs show the same clinical features and suffer the same complications as patients with sporadic disease. Age distribution between parent and offspring and telomere length shortening provide evidence of disease anticipation.
Diminished Phosphodiesterase-8B Potentiates Biphasic Insulin Response to Glucose
Authors: Dov Avital , Abramovitch Eva , Warwar Nasim , Nesher Rafael
Published: November 2007

cAMP activates multiple signal pathways, crucial for the pancreatic β-cells function and survival and is a major potentiator of insulin release. A family of phosphodiesterases (PDEs) terminate the cAMP signals. We examined the expression of PDEs in rat β-cells and their role in the regulation of insulin response. Using RT-PCR and Western blot analyses, we identified PDE3A, PDE3B, PDE4B, PDE4D, and PDE8B in rat islets and in INS-1E cells and several possible splice variants of these PDEs. Specific depletion of PDE3A with small interfering (si) RNA (siPDE3A) led to a small (67%) increase in the insulin response to glucose in INS-1E cells but not rat islets. siPDE3A had no effect on the glucagon-like peptide-1 (10 nmol/liter) potentiated insulin response in rat islets. Depletion in PDE8B levels in rat islets using similar technology (siPDE8B) increased insulin response to glucose by 70%, the potentiation being of similar magnitude during the first and second phase insulin release. The siPDE8B-potentiated insulin response was further increased by 23% when glucagon-like peptide-1 was included during the glucose stimulus. In conclusion, PDE8B is expressed in a small number of tissues unrelated to glucose or fat metabolism. We propose that PDE8B, an 3-isobutyl-1-methylxanthine-insensitive cAMP-specific phosphodiesterase, could prove a novel target for enhanced insulin response, affecting a specific pool of cAMP involved in the control of insulin granule trafficking and exocytosis. Finally, we discuss evidence for functional compartmentation of cAMP in pancreatic β-cells.
Endogenous Relaxin Does Not Affect Chronic Pressure Overload-Induced Cardiac Hypertrophy and Fibrosis
Authors: Xu Qi , Lekgabe Edna D. , Gao Xiao-Ming , Ming Ziqiu , Tregear Geoffrey W. , Dart Anthony M. , Bathgate Ross A. D. , Samuel Chrishan S. , Du Xiao-Jun
Published: November 2007

The effect of endogenous relaxin on the development of cardiac hypertrophy, dysfunction, and fibrosis remains completely unknown. We addressed this question by subjecting relaxin-1 deficient (Rln1−/−) and littermate control (Rln1+/+) mice of both genders to chronic transverse aortic constriction (TAC). The extent of left ventricular (LV) remodeling and dysfunction were studied by serial echocardiography over an 8-wk period and by micromanometry. The degree of hypertrophy was estimated by LV weight, cardiomyocyte size, and expression of relevant genes. Cardiac fibrosis was determined by hydroxyproline assay and quantitative histology. Expression of endogenous relaxin during the course of TAC was also examined. In response to an 8-wk period of pressure overload, TAC mice of both genotypes developed significant LV hypertrophy, fibrosis, hypertrophy related gene profile, and signs indicating congestive heart failure when compared with respective sham controls. The severity of these alterations was not statistically different between the two genotypes of either gender. Relaxin mRNA expression was up-regulated, whereas that of its receptor was unchanged in the hypertrophic myocardium of wild-type mice. Collectively, the extent of pressure overload-induced LV hypertrophy, fibrosis, and dysfunction were comparable between Rln1+/+ and Rln1−/− mice. Thus, although up-regulated in its expression, endogenous relaxin had no significant effect on the progression of cardiac maladaptation and dysfunction in the setting of chronic pressure overload.
Family Caregivers: A Shadow Workforce in the Geriatric Health Care System?
Authors: Bookman Ann , Harrington Mona
Published: November 2007

Based on two years of fieldwork, conducted between March 2003 and March 2005 in the health care industry of the northeastern United States, this study shows that the work of family caregivers of elders goes far beyond previously recognized care in the home to acknowledge care inside health care facilities and in conjunction with community services. It reveals that family caregivers — untrained, undersupported, and unseen — constitute a “shadow workforce,” acting as geriatric case managers, medical record keepers, paramedics, and patient advocates to fill dangerous gaps in a system that is uncoordinated, fragmented, bureaucratic, and often depersonalized. Detailed examination of what family caregivers actually do in traversing multiple domains reveals the extent of their contribution to and the weaknesses in the present geriatric health care system. It suggests that the experiences of family caregivers must be central to the creation of new policies and a more coordinated system that uses the complex work of family caregivers by providing the training and support that they need.
PAR1 specifies ciliated cells in vertebrate ectoderm downstream of aPKC
Authors: Ossipova Olga , Tabler Jacqui , Green Jeremy B. A. , Sokol Sergei Y.
Published: November 2007

Partitioning-defective 1 (PAR1) and atypical protein kinase C (aPKC) are conserved serine/threonine protein kinases implicated in the establishment of cell polarity in many species from yeast to humans. Here we investigate the roles of these protein kinases in cell fate determination in Xenopusepidermis. Early asymmetric cell divisions at blastula and gastrula stages give rise to the superficial (apical) and the deep (basal) cell layers of epidermal ectoderm. These two layers consist of cells with different intrinsic developmental potential, including superficial epidermal cells and deep ciliated cells. Our gain- and loss-of-function studies demonstrate that aPKC inhibits ciliated cell differentiation in Xenopus ectoderm and promotes superficial cell fates. We find that the crucial molecular substrate for aPKC is PAR1, which is localized in a complementary domain in superficial ectoderm cells. We show that PAR1 acts downstream of aPKC and is sufficient to stimulate ciliated cell differentiation and inhibit superficial epidermal cell fates. Our results suggest that aPKC and PAR1 function sequentially in a conserved molecular pathway that links apical-basal cell polarity to Notch signaling and cell fate determination. The observed patterning mechanism may operate in a wide range of epithelial tissues in many species.
Divergent functions of two ancientHydra Brachyuryparalogues suggest specific roles for their C-terminal domains in tissue fate induction
Authors: Bielen Holger , Oberleitner Sabine , Marcellini Sylvain , Gee Lydia , Lemaire Patrick , Bode Hans R. , Rupp Ralph , Technau Ulrich
Published: November 2007

Homologues of the T-box gene Brachyury play important roles in mesoderm differentiation and other aspects of early development in all bilaterians. In the diploblast Hydra, the Brachyuryhomologue HyBra1 acts early in the formation of the hypostome, the location of the organiser in adult Hydra. We now report the isolation and characterisation of a second Brachyury gene, HyBra2. Sequence analysis suggests that HyBra1 and HyBra2 are paralogues, resulting from an ancient lineage-specific gene duplication. We show that both paralogues acquired novel functions, both at the level of their cis-regulation as well as through significant divergence of the coding sequence. Both genes are expressed in the hypostome, but HyBra1 is predominantly endodermal, whereas HyBra2 transcripts are found primarily in the ectoderm. During bud formation, both genes are activated before any sign of evagination, suggesting an early role in head formation. During regeneration, HyBra1 is an immediate-early response gene and is insensitive to protein synthesis inhibition, whereas the onset of expression of HyBra2 is delayed and requires protein synthesis. The functional consequence of HyBra1/2 protein divergence on cell fate decisions was tested in Xenopus. HyBra1 induces mesoderm, like vertebrate Brachyury proteins. By contrast, HyBra2 shows a strong cement-gland and neural-inducing activity. Domain-swapping experiments show that the C-terminal domain of HyBra2 is responsible for this specific phenotype. Our data support the concept of sub- and neofunctionalisation upon gene duplication and show that divergence of cis-regulation and coding sequence in paralogues can lead to dramatic changes in structure and function.
Proportional-integral-plus control applications of state-dependent parameter models
Authors: Taylor C. J. , Shaban E. M. , Stables M. A. , Ako S
Published: November 2007

This paper considers proportional-integral-plus (PIP) control of non-linear systems defined by state-dependent parameter models, with particular emphasis on three practical demonstrators: a microclimate test chamber, a 1/5th-scale laboratory representation of an intelligent excavator, and a full-scale (commercial) vibrolance system used for ground improvement on a construction site. In each case, the system is represented using a quasi-linear state-dependent parameter (SDP) model structure, in which the parameters are functionally dependent on other variables in the system. The approach yields novel SDP-PIP control algorithms with improved performance and robustness in comparison with conventional linear PIP control. In particular, the new approach better handles the large disturbances and other non-linearities typical in the application areas considered.
Separation of Sulfur Compounds in Straight-Run Naphtha
Authors: Miki Yasuo , Toba Makoto , Yoshimura Yuji
Published: November 2007

Sulfur-containing compounds in straight-run naphtha were separated from coexisting hydrocarbons by means of open-column chromatography. Elution with hexane was continued after outflow of saturated hydrocarbons in the original sample, and aromatic hydrocarbons eluted gradually without any accompanying sulfur-containing compounds. When aromatic hydrocarbons ceased to be observed in the effluent, hexane was changed to benzene. A mixture of thiophenes, disulfides, and thiols then began to elute, followed ultimately by a mixture of sulfides and thiacycloalkanes. The obtained sulfur-containing compounds contained very small amounts of hydrocarbons other than the elution solvent, and their mass spectra could be observed by means of gas chromatograph-mass spectrometry.
Synthesis of CD3-Labeled 11-cis-Retinals and Application to Solid-State Deuterium NMR Spectroscopy of Rhodopsin
Authors: Tanaka Katsunori , Struts Andrey V , Krane Sonja , Fujioka Naoko , Salgado Gilmar F J , Martínez-Mayorga Karina , Brown Michael F , Nakanishi Koji
Published: November 2007

Efficient synthesis of 11-Z-retinals labeled with 2H at the C5, C9, or C13 methyl groups is described. The 2H-labeled retinals were used to regenerate the visual pigment rhodopsin for structural investigations. Solid-state 2H NMR data provided the orientation of retinal within the rhodopsin binding pocket as well as its conformation. Extension of the approach to other membrane receptors can yield knowledge of their mechanisms of activation as a guide for ligand-based drug design.
Lanthanide Ion-Induced Folding of De Novo Designed Coiled-Coil Polypeptides
Authors: Kashiwada Ayumi , Ishida Kengo , Matsuda Kiyomi
Published: November 2007

To construct a novel isoleucine zipper polypeptide that undergoes a random to coiled coil transition upon lanthanide ion binding, we designed a 37-residue polypeptide (Pep3) with a γ-carboxy glutamic acid (γ-Gla) as metal binding site. Pep3 was designed based on the sequence of the isoleucine zipper polypeptide (Pep1), forming a triple-stranded coiled coil. The coiled-coil structure was destabilized by ionic repulsions among γ-Gla residues at position 21 (hydrophobic 3a position) of one strand. On the other hand, a stable coiled coil formed in the presence of Eu3+ ions. This structural change in the designed polypeptide was selective toward Eu3+ ion from the circular dichroism (CD) measurements. Furthermore, we designed a lanthanide ion-induced heterotrimeric coiled-coil-assembled system by using two kinds of polypeptides, Pep4 and Pep5. CD spectroscopy, sedimentation equilibrium centrifugation, gel filtration, and HPLC analyses indicate that Pep4 and Pep5 could noncovalently assemble in a 1:2 ratio in the presence of Eu3+ ions.
The Alkylation of Biphenyl over One-Dimensional Twelve-Membered Ring Zeolites. The Influence of Zeolite Structure and Alkylating Agent on the Selectivity for 4,4′-Dialkylbiphenyl
Authors: Sugi Yoshihiro , Maekawa Hiroyoshi , Ito Akira , Ozawa Chikako , Shibata Tomoko , Niimi Akihiro , Asaoka Chihara , Komura Kenichi , Kubota Yoshihiro , Lee Jae-Youl , Kim Jong-Ho , Seo Gon
Published: November 2007

Alkylation, i.e., isopropylation, s-butylation, and t-butylation, of biphenyl (BP) was examined over one-dimensional twelve-membered (12-MR) zeolites: Mordenite (MOR) and SSZ-24 (AFI) with straight channels, and SSZ-55 (ATS) and SSZ-42 (IFR) with corrugated channels. Types of zeolites and alkylating agents highly influenced the selectivities for dialkylbiphenyl (DABP) isomers. Shape-selective formation of 4,4′-diisopropylbiphenyl (4,4′-DIPB) was observed over MOR and AFI; however, ATS and IFR gave 4,4′-DIPB only in low selectivities at 250 °C: 87% over MOR, 60% over AFI, 20% over ATS, and 30% over IFR. The selectivities for 4,4′-di-s-butylbiphenyl (4,4′-DSBB) in the s-butylation were higher than those for 4,4′-DIPB: 95% over MOR, 85% over AFI, 75% over ATS, and 50% over IFR. The t-butylation afforded selectively 4,4′-di-t-butylbiphenyl (4,4′-DTBB) over the zeolites: 96–97% over MOR and AFI, 90% over ATS, and 80% over IFR. These results in the alkylation indicate the exclusion of 4,4′-DABP from other bulky DABP isomers by steric restriction in zeolite channels is an important key for the high shape-selectivity. Even zeolites with large channels, such as ATS and IFR, can have shape-selective nature if the bulky moieties, such as s-butyl and t-butyl groups, are large enough to differentiate the transition state of the least bulky 4,4′-DABP from those of the other isomers inside their channels. The selectivity for 4,4′-DABP decreased at high temperatures in some alkylations: isopropylation over MOR, and s-butylation and t-butylation over MOR, AFI, and ATS. The decreases are due to the isomerization of 4,4′-DABP at external acid sites, because the channels are not large enough for the isomerization of 4,4′-DABP to bulkier 3,4′-DABP. However, the isopropylation over AFI was accompanied by the isomerization of 4,4′-DIPB at external and internal acid sites, because the channels are large enough for the isomerization of 4,4′-DIPB.
Hydrogen Gas Diffusion Electrode Prepared from Porous Carbon Spheres Dispersed with Pd–Ag Alloy Nanoparticles
Authors: Horigome Masataka , Pacheco Tanaka David A , Llosa Tanco Margot A , Yukita Waki , Kobayashi Kiyoshi , Suzuki Toshishige M
Published: November 2007

Hydrogen gas diffusion electrodes were prepared from porous carbon spheres dispersed with Pd–Ag alloy nanoparticles with various Pd/Ag ratios. The performance of the electrodes evaluated by observing the polarization characteristics in the electro-oxidation of hydrogen markedly depended on the ratio of Pd and Ag in the alloy.
A Noniterative Algorithm for the Linear-Quadratic Profit-Maximization Model for Smoothing Multiproduct Production
Authors: Singhal Jaya , Singhal Kalyan
Published: November 2007

In multiproduct-production and workforce-smoothing problems, the objective is to determine the levels of employment and production for each product in each period that will maximize the total profit over a planning horizon of N periods given quadratic revenue and cost functions for M products. The planned levels of production, in turn, determine the planned levels of inventory or backorders for each product in each period. A real-world problem may involve 20,000 products and 12 periods, leading to over 480,000 variables. This requires solving simultaneous equations with as many variables. We exploited the staircase structure of optimality conditions to develop an algorithm that requires solving, without iterations, simultaneous equations with only three variables. The computation time, regardless of the number of variables in the model, is of the order of one second on a Vax 11/780. This algorithm also facilitates sensitivity analysis and generation of alternate plans for production, the workforce, and sales.
Selecting a Selection Procedure
Authors: Branke Jürgen , Chick Stephen E. , Schmidt Christian
Published: November 2007

Selection procedures are used in a variety of applications to select the best of a finite set of alternatives. “Best” is defined with respect to the largest mean, but the mean is inferred with statistical sampling, as in simulation optimization. There are a wide variety of procedures, which begs the question of which selection procedure to select. The main contribution of this paper is to identify, through extensive experimentation, the most effective selection procedures when samples are independent and normally distributed. We also (a) summarize the main structural approaches to deriving selection procedures, (b) formalize new sampling allocations and stopping rules, (c) identify strengths and weaknesses of the procedures, (d) identify some theoretical links between them, and (e) present an innovative empirical test bed with the most extensive numerical comparison of selection procedures to date. The most efficient and easiest to control procedures allocate samples with a Bayesian model for uncertainty about the means and use new adaptive stopping rules proposed here.
Choosing Among Living-Donor and Cadaveric Livers
Authors: Alagoz Oguzhan , Maillart Lisa M. , Schaefer Andrew J. , Roberts Mark S.
Published: November 2007

The only therapy for a patient with end-stage liver disease (ESLD) is liver transplantation, which is performed by using either a cadaveric liver from a deceased donor or a portion of a living-donor's liver. This study addresses the following decision problem for an ESLD patient with an available living donor. Should she have a transplantation now or wait? If she decides to have the transplantation now, should she use her living-donor liver or a cadaveric liver for transplantation? We formulate this problem as a discrete-time, infinite-horizon Markov decision process model and solve it using clinical data. Because living donors are typically related to the recipient, we incorporate a disutility associated with using the living-donor liver as opposed to using a cadaveric liver. We perform a structural analysis of the model, including a set of intuitive conditions that ensure the existence of structured policies such as an at-most-three-region (AM3R) optimal policy. Our computational experiments confirm that the optimal policy is typically of AM3R type.
Coherence and Consistency of Investors' Probability Judgments
Authors: Budescu David V. , Du Ning
Published: November 2007

This study investigates the quality of direct probability judgments and quantile estimates with a focus on calibration and consistency. The two response modes use different measures of miscalibration, so it is difficult to directly compare their relative (in)accuracy. We employed a more refined within-subject design in which decision makers (DMs) used both response modes to make judgments about a random sample of stocks accompanied by identical information to facilitate comparison between the two judgment methods. DMs judged the probabilities that the stocks will reach a certain threshold, provided lower and upper bounds of these forecasts, and estimated median, 50%, 70%, and 90% confidence intervals of their future prices. We found that the judgments were internally consistent and coherent, but in most cases they were slightly miscalibrated. We used several new methods of analysis that allow for more precise and reliable comparison between the two response modes. We inferred point probability estimates for the target events from the confidence intervals and analyzed them by the same methods applied to binary judgments. Interestingly, when we quantified miscalibration in identical fashion for both methods we did not find evidence of differential levels of miscalibration for the probability judgments and the confidence intervals. We discuss the theoretical and practical implications of these results.
Research Note—Should Consumers Use the Halo to Form Product Evaluations?
Authors: Boatwright Peter , Kalra Ajay , Zhang Wei
Published: November 2007

In purchase situations where attribute information is either missing or difficult to judge, a well-known heuristic that consumers use to form evaluations is the halo effect. The psychology literature has widely considered the halo a reflection of consumers' inability to discriminate between different attributes and have therefore labeled it the “halo error” or the “logical error.” The objective of this paper is to offer a rationale for the halo effect. We use a decision-theory framework to show that the halo is consistent with the goal of minimizing estimation risk. Contrary to conventional wisdom, we demonstrate that a decision using the halo has lower estimation risk compared to not using the halo heuristic. Therefore, using the halo results in utility maximization and is indicative of rational behavior.
An Empirical Study of System Improvement by Frontline Employees in Hospital Units
Authors: Tucker Anita L.
Published: November 2007

This paper investigates the conditions under which frontline employees take initiative to improve their work systems to prevent operational failures. Drawing on the system improvement and team learning literatures, we develop a framework of frontline system improvement and test it using survey data from 37 workgroups. We find that psychological safety—the belief that one can talk about errors without risk of punishment—and problem-solving efficacy—the belief that the organization will support employees' system improvement efforts—were positively correlated with frontline system improvement (FLSI). Surprisingly, felt responsibility was negatively associated with FLSI. These findings suggest that rather than relying on hiring motivated individuals, managers need to support employees' efforts to improve their work systems by creating a work environment where it is safe to talk about operational failures and responding to employee communication about operational failures. Doing this may result in higher levels of FLSI efforts and ultimately improve work processes.
Demand Estimation and Assortment Optimization Under Substitution: Methodology and Application
Authors: Kök A. Gürhan , Fisher Marshall L.
Published: November 2007

Assortment planning at a retailer entails both selecting the set of products to be carried and setting inventory levels for each product. We study an assortment planning model in which consumers might accept substitutes when their favorite product is unavailable. We develop an algorithmic process to help retailers compute the best assortment for each store. First, we present a procedure for estimating the parameters of substitution behavior and demand for products in each store, including the products that have not been previously carried in that store. Second, we propose an iterative optimization heuristic for solving the assortment planning problem. In a computational study, we find that its solutions, on average, are within 0.5% of the optimal solution. Third, we establish new structural properties (based on the heuristic solution) that relate the products included in the assortment and their inventory levels to product characteristics such as gross margin, case-pack sizes, and demand variability. We applied our method at Albert Heijn, a supermarket chain in The Netherlands. Comparing the recommendations of our system with the existing assortments suggests a more than 50% increase in profits.
Supply Chain Scheduling: Conflict and Cooperation in Assembly Systems
Authors: Chen Zhi-Long , Hall Nicholas G.
Published: November 2007

We study conflict and cooperation issues in supply chain manufacturing. Consider an assembly system where suppliers provide parts to a manufacturer. A product cannot be delivered until all its parts have been supplied. The manufacturer performs nonbottleneck operations, for example, outsourced assembly, packaging, and delivery for each product. Two classical scheduling objectives are considered: minimization of the total completion time and of the maximum lateness. We analyze how far from optimal the best schedule for a suppliers' scheduling problem can be for the corresponding manufacturer's problem, and vice versa. To resolve these conflicts, we consider four alternative scenarios for the relative bargaining power of the suppliers and the manufacturer, and in each case describe a practical mechanism for cooperation between the decision makers. Evaluating the cost of conflict and the benefit of cooperation in these scenarios requires the solution of various scheduling problems by the suppliers, the manufacturer, and the overall system. For all these scheduling problems, we provide either an efficient algorithm or a proof of intractability. Moreover, for two problems that we show are intractable, we describe heuristics and analyze their worst case performance or demonstrate asymptotic optimality of their solutions. We demonstrate computationally that the cost saving realized by cooperation between the decision makers is significant in many cases. Extensions of our models to consider bottleneck operations at the manufacturer and transportation times are also developed.
Diversity Maximization Approach for Multiobjective Optimization
Authors: Masin Michael , Bukchin Yossi
Published: November 2007

One of the most common approaches for multiobjective optimization is to generate the whole or partial efficient frontier and then decide about the preferred solution in a higher-level decision-making process. In this paper, a new method for generating the efficient frontier for multiobjective problems is developed, called the diversity maximization approach (DMA). This approach is capable of solving mixed-integer and combinatorial problems. The DMA finds Pareto optimal solutions by maximizing a proposed diversity measure and guarantees generating the complete set of efficient points. Given a subset of the efficient frontier, DMA finds the next Pareto optimal solution which, combined with the existing ones, yields the most diversified subset of efficient points. This solution is defined as the most diverse solution. In fact, it aims to maximize the distance between the new efficient point and the closest point in the given subset of the efficient frontier. The proposed approach can be applied to any problem that can be solved for the single-objective case. We can use the DMA by solving directly a modified version of the mixed-integer programming (MIP) formulation of the multiobjective problem. In this case, the Pareto optimal solutions are found sequentially in an iterative way. Consequently, as we terminate the procedure before completion, a partial efficient frontier is available. The diversity measure assures that in every stage of the procedure, the partial efficient frontier is well diversified. This partial efficient frontier can be perceived as a filtered set of the complete efficient frontier and can be used by the decision maker in case the complete efficient frontier contains too many points. An additional way of using DMA is by incorporating it in a problem oriented branch-and-bound algorithm. Detailed examples of both approaches are given.
Pricing Options in Jump-Diffusion Models: An Extrapolation Approach
Authors: Feng Liming , Linetsky Vadim
Published: November 2007

We propose a new computational method for the valuation of options in jump-diffusion models. The option value function for European and barrier options satisfies a partial integrodifferential equation (PIDE). This PIDE is commonly integrated in time by implicit-explicit (IMEX) time discretization schemes, where the differential (diffusion) term is treated implicitly, while the integral (jump) term is treated explicitly. In particular, the popular IMEX Euler scheme is first-order accurate in time. Second-order accuracy in time can be achieved by using the IMEX midpoint scheme. In contrast to the above approaches, we propose a new high-order time discretization scheme for the PIDE based on the extrapolation approach to the solution of ODEs that also treats the diffusion term implicitly and the jump term explicitly. The scheme is simple to implement, can be added to any PIDE solver based on the IMEX Euler scheme, and is remarkably fast and accurate. We demonstrate our approach on the examples of Merton's and Kou's jump-diffusion models, the diffusion-extended variance gamma model, as well as the two-dimensional Duffie-Pan-Singleton model with correlated and contemporaneous jumps in the stock price and its volatility. By way of example, pricing a one-year double-barrier option in Kou's jump-diffusion model, our scheme attains accuracy of 10−5 in 72 time steps (in 0.05 seconds). In contrast, it takes the first-order IMEX Euler scheme more than 1.3 million time steps (in 873 seconds) and the second-order IMEX midpoint scheme 768 time steps (in 0.49 seconds) to attain the same accuracy. Our scheme is also well suited for Bermudan options. Combining simplicity of implementation and remarkable gains in computational efficiency, we expect this method to be very attractive to financial engineering modelers.
Technical Note—Note on “Myopic Heuristics for the Random Yield Problem”
Authors: Inderfurth Karl , Transchel Sandra
Published: November 2007

Bollapragada and Morton (1999) present several well-performing heuristics for solving the periodic inventory problem with random yield and demand. Their approach is essentially based on a transformation of the single-period problem into a standard newsvendor problem with deterministic yield and random demand which, however, is supply dependent. In our note, we show that their evaluation of the respective optimality condition is not correct. This explains the steady deterioration of their myopic heuristics for parameter constellations that correspond to increasing service levels. Some computational investigations reveal that the performance of the heuristics can become quite poor if service levels are high and exceed those values for which results are reported in the original study. Nonetheless, up to now these heuristics are still the best ones available for solving the joint random yield problem.
Errata to “Inventory Cost Rate Functions with Nonlinear Shortage Costs”
Authors: Rosling Kaj
Published: November 2007

Rosling (2002) presents and analyzes five different cost-rate functions for single-item inventory models. The functions are referred to as Models 1–5. These errata correct an erroneous comment concerning Model 3 and render a rigorous argument for the functional form of Model 2.
A Learning Approach for Interactive Marketing to a Customer Segment
Authors: Bertsimas Dimitris , Mersereau Adam J.
Published: November 2007

When a marketer in an interactive environment decides which messages to send to her customers, she may send messages currently thought to be most promising (exploitation) or use poorly understood messages for the purpose of information gathering (exploration). We assume that customers are already clustered into homogeneous segments, and we consider the adaptive learning of message effectiveness within a customer segment. We present a Bayesian formulation of the problem in which decisions are made for batches of customers simultaneously, although decisions may vary within a batch. This extends the classical multiarmed bandit problem for sampling one-by-one from a set of reward populations. Our solution methods include a Lagrangian decomposition-based approximate dynamic programming approach and a heuristic based on a known asymptotic approximation to the multiarmed bandit solution. Computational results show that our methods clearly outperform approaches that ignore the effects of information gain.
The Capacitated m-Ring-Star Problem
Authors: Baldacci R. , Dell'Amico M. , González J. Salazar
Published: November 2007

The Capacitated m-Ring-Star Problem (CmRSP) is the problem of designing a set of rings that pass through a central depot and through some transition points and/or customers, and then assigning each nonvisited customer to a visited point or customer. The number of customers visited and assigned to a ring is bounded by an upper limit: the capacity of the ring. The objective is to minimize the total routing cost plus assignment costs. The problem has practical applications in the design of urban optical telecommunication networks. This paper presents and discusses two integer programming formulations for the CmRSP. Valid inequalities are proposed to strengthen the linear programming relaxation and are used as cutting planes in a branch-and-cut approach. The procedure is implemented and tested on a large family of instances, including real-world instances, and the good performance of the proposed approach is demonstrated.
Repeated Commit-or-Defer Decisions with a Deadline: The Influenza Vaccine Composition
Authors: Kornish Laura J. , Keeney Ralph L.
Published: November 2007

Seasonal products have an effective inventory deadline, a time by which the inventory must be ready to distribute. The deadline creates an incentive to start early with production. However, opportunities to gather information that might change production decisions provide an incentive to defer the start of production. We study the resultant dynamic decision problem with alternatives that commit to one of several courses of action now and an alternative to defer the commitment to gather more information about the possible consequences of each alternative. The deadline increases the effective cost of gathering information because that cost includes the value sacrificed by reducing the time available to produce inventory. We frame our model using the annual influenza vaccine composition decision: deciding between strains of the virus to include, which must happen in the spring to allow time for vaccine production before the fall flu season begins. Our analysis describes the optimal decision strategies for this commit-or-defer decision. Many insights are drawn from this model that could contribute to more informed flu vaccine composition decisions. We comment on the relevance of this commit-or-defer decision model to a firm's production decisions for other seasonal products with an inventory deadline such as fashion goods.
Scything the grass: agenda-setting consequences of appointing public inquiries in the UK. A longitudinal analysis
Authors: Sulitzeanu-Kenan Raanan
Published: November 2007

English

The media salience trends of 40 events in the UK between 1984 and 2003 were examined to determine the validity of allegations regarding the agenda-setting effect of appointing public inquiries. Results show that, contrary to the ‘long grass’ argument, the attenuation in media salience following the appointment of a public inquiry is not different from that of non-inquired events. The findings are analysed and an alternative explanation is suggested for the prevalence of the ‘long grass’ argument.