bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Website Characteristics on a Consumer's Urge to Buy Impulsively
Authors: Parboteeah D. Veena , Valacich Joseph S. , Wells John D.
Published: June 2008

With the proliferation of e-commerce, there is growing evidence that online impulse buying is occurring, yet relatively few researchers have studied this phenomenon. This paper reports on two studies that examine how variations in a website influence online impulse buying. The results reveal some relevant insights about this phenomenon. Specifically, although many participants had the urge to buy impulsively, regardless of website quality, this behavior's likelihood and magnitude was directly influenced by varying the quality of task-relevant and mood-relevant cues. Task-relevant cues include characteristics, such as navigability, that help in the attainment of the online consumer's shopping goal. Conversely, mood-relevant cues refer to the characteristics, such as visual appeal, that affect the degree to which a user enjoys browsing a website but that do not directly support a particular shopping goal. The implications of the results for both future research and the design of human-computer interfaces are discussed.
User Awareness of Security Countermeasures and Its Impact on Information Systems Misuse: A Deterrence Approach
Authors: D'Arcy John , Hovav Anat , Galletta Dennis
Published: June 2008

Intentional insider misuse of information systems resources (i.e., IS misuse) represents a significant threat to organizations. For example, industry statistics suggest that between 50%–75% of security incidents originate from within an organization. Because of the large number of misuse incidents, it has become important to understand how to reduce such behavior. General deterrence theory suggests that certain controls can serve as deterrent mechanisms by increasing the perceived threat of punishment for IS misuse. This paper presents an extended deterrence theory model that combines work from criminology, social psychology, and information systems. The model posits that user awareness of security countermeasures directly influences the perceived certainty and severity of organizational sanctions associated with IS misuse, which leads to reduced IS misuse intention. The model is then tested on 269 computer users from eight different companies. The results suggest that three practices deter IS misuse: user awareness of security policies; security education, training, and awareness (SETA) programs; and computer monitoring. The results also suggest that perceived severity of sanctions is more effective in reducing IS misuse than certainty of sanctions. Further, there is evidence that the impact of sanction perceptions vary based on one's level of morality. Implications for the research and practice of IS security are discussed.
Impact of the Union and Difference Operations on the Quality of Information Products
Authors: Parssian Amir , Sarkar Sumit , Jacob Varghese S.
Published: June 2008

Information derived from relational databases is routinely used for decision making. However, little thought is usually given to the quality of the source data, its impact on the quality of the derived information, and how this in turn affects decisions. To assess quality, one needs a framework that defines relevant metrics that constitute the quality profile of a relation, and provides mechanisms for their evaluation. We build on a quality framework proposed in prior work, and develop quality profiles for the result of the primitive relational operations Difference and Union. These operations have nuances that make both the classification of the resulting records as well as the estimation of the different classes quite difficult to address, and very different from that for other operations. We first determine how tuples appearing in the results of these operations should be classified as accurate, inaccurate or mismember, and when tuples that should appear do not (called incomplete) in the result. Although estimating the cardinalities of these subsets directly is difficult, we resolve this by decomposing the problem into a sequence of drawing processes, each of which follows a hyper-geometric distribution. Finally, we discuss how decisions would be influenced based on the resulting quality profiles.
Does Fit Matter? The Impact of Task-Technology Fit and Appropriation on Team Performance in Repeated Tasks
Authors: Fuller Robert M. , Dennis Alan R.
Published: June 2008

Prior research on technology and team performance concludes that the fit of the technology to tasks influences team performance. It also suggests that the way teams appropriate technology influences performance. This research examines how fit and appropriation (from the Fit Appropriation Model) influence performance over time. Initially, the results show that fit better predicted performance; teams using poor-fitting technology performed worse than teams with better fitting technology. However, over a short time period (two days in this study), this initial fit no longer predicted performance; performance of teams using better fitting technology remained constant while teams using poor-fitting technology innovated and adapted, improving performance. There are two key findings from this study. First, fit can predict team performance soon after technology adoption, but initial assessments of fit are temporary as teams innovate and adapt; thus, our current theoretical models of fitting technology to a task likely will not be useful beyond the first use. Second, teams should understand how to better adapt existing technology and work structures. Because our current theories of task-technology fit failed to predict performance beyond the first use of technology, we believe that this calls for a reconsideration of what fit means for teams using technology.
Designing Intelligent Software Agents for Auctions with Limited Information Feedback
Authors: Adomavicius Gediminas , Gupta Alok , Zhdanov Dmitry
Published: June 2008

This paper presents analytical, computational, and empirical analyses of strategies for intelligent bid formulations in online auctions. We present results related to a weighted-average ascending price auction mechanism that is designed to provide opaque feedback information to bidders and presents a challenge in formulating appropriate bids. Using limited information provided by the mechanism, we design strategies for software agents to make bids intelligently. In particular, we derive analytical results for the important characteristics of the auction, which allow estimation of the key parameters; we then use these theoretical results to design several bidding strategies. We demonstrate the validity of designed strategies using a discrete event simulation model that resembles the mechanisms used in treasury bills auctions, business-to-consumer (B2C) auctions, and auctions for environmental emission allowances. In addition, using the data generated by the simulation model, we show that intelligent strategies can provide a high probability of winning an auction without significant loss in surplus.
Choice and Chance: A Conceptual Model of Paths to Information Security Compromise
Authors: Ransbotham Sam , Mitra Sabyasachi
Published: June 2008

No longer the exclusive domain of technology experts, information security is now a management issue. Through a grounded approach using interviews, observations, and secondary data, we advance a model of the information security compromise process from the perspective of the attacked organization. We distinguish between deliberate and opportunistic paths of compromise through the Internet, labeled choice and chance, and include the role of countermeasures, the Internet presence of the firm, and the attractiveness of the firm for information security compromise. Further, using one year of alert data from intrusion detection devices, we find empirical support for the key contributions of the model. We discuss the implications of the model for the emerging research stream on information security in the information systems literature.
Fluid Models for Overloaded Multiclass Many-Server Queueing Systems with First-Come, First-Served Routing
Authors: Talreja Rishi , Whitt Ward
Published: June 2008

Motivated by models of tenant assignment in public housing, we study approximating deterministic fluid models for overloaded queueing systems having multiple customer classes (classes of tenants) and multiple service pools (housing authorities), each with many servers (housing units). Customer abandonment acts to keep the system stable, yielding a proper steady-state description. Motivated by fairness considerations, we assume that customers are selected for service by newly available servers on a first-come, first-served (FCFS) basis from all classes the corresponding service pools are allowed to serve. In this context, it is challenging to determine stationary routing flow rates between customer classes and service pools. Given those routing flow rates, each single fluid queue can be analyzed separately using previously established methods. Our ability to determine the routing flow rates depends on the structure of the network routing graph. We obtain the desired routing flow rates in three cases: when the routing graph is (i) a tree (sparsely connected), (ii) complete bipartite (fully connected), and (iii) an appropriate combination of the previous two cases. Other cases remain unsolved. In the last two solved cases, the routing flow rates are actually not uniquely determined by the fluid model, but become so once we make stochastic assumptions about the queueing models that the fluid model approximates.
An Integrated Decision-Making Approach for Improving European Air Traffic Management
Authors: Grushka-Cockayne Yael , Reyck Bert De , Degraeve Zeger
Published: June 2008

We develop a multistakeholder, multicriteria decision-making framework for Eurocontrol, the European air traffic management organization, for evaluating and selecting operational improvements to the air traffic management system. The selected set of improvements will form the master plan of the Single European Sky initiative for harmonizing air traffic, in an effort to cope with the forecasted increase in air traffic, while maintaining safety, protecting the environment, and improving predictability and efficiency. The challenge is to select the set of enhancements such that the required performance targets are met and all key stakeholders are committed to the decisions. In this paper, we develop and implement a model to identify a preferred set of improvements to the arrival and departure procedures to and from airports. We provide an integrated approach for valuing a large number of alternatives, while considering interactions among them. The model combines quantitative and qualitative expert assessments of the possible enhancements and identifies commonalities and differences in the stakeholders' perspectives, ultimately recommending a preferred course of action. The model is currently being adopted by Eurocontrol as the formal trade-off analysis methodology supporting all enhancements' decision-making discussions throughout the construction of the master plan.
Videoconferencing in the Field: A Heuristic Processing Model
Authors: Ferran Carlos , Watts Stephanie
Published: June 2008

This research uses dual-process cognitive theory to describe how people process information differently when it is delivered via videoconference rather than when it is delivered face-to-face. According to this theory, relative to face-to-face communication, people in videoconferences tend to be more influenced by heuristic cues—such as how likeable they perceive the speaker to be—than by the quality of the arguments presented by the speaker. This is due to the higher cognitive demands that videoconferencing places on participants. We report on a field study of medical professionals in which we found differences in information processing as predicted: participants attending a seminar via videoconference were more influenced by the likeability of the speaker than by the quality of the arguments presented, whereas the opposite pattern was true for participants attending in-person. We also found that differences in cognitive load explain these effects. The discussion on the theoretical model and associated findings explains why prior videoconference studies have not consistently found main effects for media. The findings also show that videoconferencing is not like face-to-face communication, despite apparent similarities.
Multiple Part-Type Production in Robotic Cells: Equivalence of Two Real-World Models
Authors: Dawande Milind , Pinedo Michael , Sriskandarajah Chelliah
Published: June 2008

We address the scheduling of operations in a robotic cell that produces multiple part-types. The objective is to obtain a cyclic schedule—a sequence of robot moves and an ordering of the parts—that minimizes the long-run average time to produce a part or, equivalently, maximizes the throughput.

We consider two different models that are currently used in practice. The first is a single-gripper cell with a unit-capacity output buffer at each machine. The second is a bufferless dual-gripper cell. We focus our analysis on a widely used class of cyclic solutions, referred to as CRM cycles. The main outcome of our analysis is the equivalence of the two models (i.e., the maximum throughput is the same for both models) under conditions that are common in practice. The equivalence is established in two steps: (i) identification of a subset of dominating cyclic solutions for each model, and (ii) provision of a one-to-one mapping between these dominating cycles such that corresponding cycles have the same throughput. We also analyze the computational complexity of the throughput maximization problem for the two models.

The enhanced capabilities (i.e., output buffers and dual gripper) of both models were motivated by a need to improve the throughput. However, the costs of acquiring these capabilities differ significantly. Our discussions with operations managers at a Dallas-area robotic cell manufacturer revealed that the total cost of designing and programming the robot's control mechanism for a cell with output buffers is about 20% less than that for a dual-gripper cell. The equivalence of the two models is, therefore, somewhat surprising and has significant practical implications. For cells that operationalize CRM cycles, the use of output buffers instead of a dual gripper can result in considerable savings without compromising throughput.
Unpacking Prior Experience: How Career History Affects Job Performance
Authors: Dokko Gina , Wilk Steffanie L. , Rothbard Nancy P.
Published: June 2008

As individuals change jobs more frequently, it is increasingly important to understand what they carry from their prior work experience that affects their performance in a new organizational context. So far, explanations about the imperfect portability of experience have primarily been about firm specificity of knowledge and skill. We draw on psychological theory to propose additional sociocognitive factors that interfere with the transfer of knowledge and skill acquired from prior related work experience. As we hypothesized, we find that task-relevant knowledge and skill mediates the relationship between prior related experience and job performance and that it acts as suppressing mediator of a negative direct relationship between prior related experience and current job performance. We also find that the positive effect of prior related experience on task-relevant knowledge and skill is attenuated by higher levels of experience within the current firm.
Within-Subject Variability and Analytic Imprecision of Insulinlike Growth Factor Axis and Collagen Markers: Implications for Clinical Diagnosis and Doping Tests
Authors: Nguyen Tuan V , Nelson Anne E , Howe Christopher J , Seibel Markus J , Baxter Robert C , Handelsman David J , Kazlauskas Ray , Ho Ken K
Published: June 2008

Background: The utility of insulinlike growth factor (IGF) axis and collagen markers for a growth hormone (GH) doping test in sport depends on their stability and reproducibility. We sought to determine short-term within-subject variability of these markers in a large cohort of healthy individuals.

Methods: We measured IGF-I, IGF binding protein 3 (IGFBP-3), acid labile subunit (ALS), and the collagen markers N-terminal propeptide of type I procollagen (PINP), C-terminal telopeptide of type I collagen (ICTP), and N-terminal propeptide of type III procollagen (PIIINP) in serum samples obtained on multiple occasions (median 3 per participant) over a 2- to 3-week period from 1103 elite athletes (699 men, 404 women) ages 22.2 (5.2) years [mean (SD)]. We estimated between-subject and within-subject variances by mixed–effects ANOVA.

Results: Within-subject variance accounted for 32% to 36% and 4% to 13% of the total variance in IGF markers and collagen markers, respectively. The within-subject CV ranged from 11% to 21% for the IGF axis markers and from 13% to 15% for the collagen markers. The index of individuality for the IGF axis markers was 0.66–0.76, and for the collagen markers, 0.26–0.45. For each marker, individuals with initial extreme measured values tended to regress toward the population mean in subsequent repeated measurements. We developed a Bayesian model to estimate the long-term probable value for each marker.

Conclusions: These results indicate that in healthy individuals the within-subject variability was greater for IGF-I than for the collagen markers, and that where a single measurement is available, it is possible to estimate the long-term probable value of each of the markers by applying the Bayesian approach. Such an application can increase the reliability and decrease the cost of detecting GH doping.
The success rate of I-131 ablation in differentiated thyroid cancer: comparison of uptake-related and fixed-dose strategies
Authors: Verkooijen Robbert B T , Verburg Frederik A , van Isselt Johannes W , Lips Cornelis J M , Smit Jan W , Stokkel Marcel P M
Published: June 2008

Introduction

The aim of the study was to compare the success rate of an uptake-related ablation protocol in which the dose depends on an I-131 24-h neck uptake measurement and a fixed-dose ablation protocol in which the dose depends on tumour stage.

Methods

All differentiated thyroid carcinoma patients with M0 disease who had undergone (near-) total thyroidectomy followed by I-131 ablation were included. In the uptake-related ablation protocol, 1100 (uptake >10%), 1850 (uptake 5–10%) and 2800 MBq (uptake <5%) were used. In the fixed-dosage ablation strategy, 3700 (T1–3, N0 stage) and 5550 MBq (N1 and/or T4 stage) were applied. We used I-131 uptake on whole-body scintigraphy and thyroglobulin-off values to evaluate the ablation 6–12 months after treatment.

Results

In the uptake-related ablation protocol, 60 out of 139 (43%) patients were successfully treated versus 111 out of 199 for the fixed-dose ablation protocol (56%) (P=0.022). The differences were not statistically significant for patients with T4 (P=0.581) and/or N1 (P=0.08) disease or for patients with T4N1 tumour stage (P=0.937).

Conclusion

The fixed-dose I-131 ablation protocol is more effective in ablation of the thyroid remnant in differentiated thyroid carcinoma patients than an uptake-related ablation protocol. This difference is not observed in patients with a N1 and/or T4 tumour stage.
Hormone-related tumors in transsexuals receiving treatment with cross-sex hormones
Authors: Mueller Andreas , Gooren Louis
Published: June 2008

Objective

To assess the risk of development of hormone-related tumors in transsexuals receiving treatment with cross-sex hormones.

Design

Description of cases of transsexuals who have developed a hormone-related malignancy observed in their own clinic or reported in the literature. Recommendations for early diagnosis and prevention are presented.

Methods

Review of the literature in PubMed.

Results

In male-to-female transsexuals receiving estrogen administration, lactotroph adenomas, breast cancer, and prostate cancer have been reported. In female-to-male transsexuals receiving treatment with testosterone, a single case of breast carcinoma and several cases of ovarian cancer have been reported. So far endometrial cancer has not been encountered though it remains a potential malignant development.

Conclusions

There are so far only a few cases of hormone-related cancer in transsexuals. There may be an underreporting. The probability of a hormone-related tumor increases with the duration of exposure to cross-sex hormones and the aging of the population of transsexuals.
Deletion of Cd39/Entpd1 Results in Hepatic Insulin Resistance
Authors: Enjyoji Keiichi , Kotani Ko , Thukral Chandrashekar , Blumel Benjamin , Sun Xiaofeng , Wu Yan , Imai Masato , Friedman David , Csizmadia Eva , Bleibel Wissam , Kahn Barbara B. , Robson Simon C.
Published: June 2008

OBJECTIVE—Extracellular nucleotides are important mediators of inflammatory responses and could also impact metabolic homeostasis. Type 2 purinergic (P2) receptors bind extracellular nucleotides and are expressed by major peripheral tissues responsible for glucose homeostasis. CD39/ENTPD1 is the dominant vascular and immune cell ectoenzyme that hydrolyzes extracellular nucleotides to regulate purinergic signaling.

RESEARCH DESIGN AND METHODS—We have studied Cd39/Entpd1-null mice to determine whether any associated changes in extracellular nucleotide concentrations influence glucose homeostasis.

RESULTS—Cd39/Entpd1-null mice have impaired glucose tolerance and decreased insulin sensitivity with significantly higher plasma insulin levels. Hyperinsulinemic-euglycemic clamp studies indicate altered hepatic glucose metabolism. These effects are mimicked in vivo by injection into wild-type mice of either exogenous ATP or an ecto-ATPase inhibitor, ARL-67156, and by exposure of hepatocytes to extracellular nucleotides in vitro. Increased serum interleukin-1β, interleukin-6, interferon-γ, and tumor necrosis factor-α levels are observed in Cd39/Entpd1-null mice in keeping with a proinflammatory phenotype. Impaired insulin sensitivity is accompanied by increased activation of hepatic c-Jun NH2-terminal kinase/stress-activated protein kinase in Cd39/Entpd1 mice after injection of ATP in vivo. This results in decreased tyrosine phosphorylation of insulin receptor substrate-2 with impeded insulin signaling.

CONCLUSIONS—CD39/Entpd1 is a modulator of extracellular nucleotide signaling and also influences metabolism. Deletion of Cd39/Entpd1 both directly and indirectly impacts insulin regulation and hepatic glucose metabolism. Extracellular nucleotides serve as “metabolokines,” indicating further links between inflammation and associated metabolic derangements.
Effects of a Selective Serotonin Reuptake Inhibitor, Fluoxetine, on Counterregulatory Responses to Hypoglycemia in Healthy Individuals
Authors: Briscoe Vanessa J. , Ertl Andrew C. , Tate Donna B. , Dawling Sheila , Davis Stephen N.
Published: June 2008

OBJECTIVE—Hypoglycemia commonly occurs in intensively-treated diabetic patients. Repeated hypoglycemia blunts counterregulatory responses, thereby increasing the risk for further hypoglycemic events. Currently, physiologic approaches to augment counterregulatory responses to hypoglycemia have not been established. Therefore, the specific aim of this study was to test the hypothesis that 6 weeks’ administration of the selective serotonin reuptake inhibitor (SSRI) fluoxetine would amplify autonomic nervous system (ANS) and neuroendocrine counterregulatory mechanisms during hypoglycemia.

RESEARCH DESIGN AND METHODS—A total of 20 healthy (10 male and 10 female) subjects participated in an initial single-step hyperinsulinemic (9 pmol · kg−1 · min−1)-hypoglycemic (means ± SE 2.9 ± 0.1 mmol/l) clamp study and were then randomized to receive 6 weeks’ administration of fluoxetine (n = 14) or identical placebo (n = 6) in a double-blind fashion. After 6 weeks, subjects returned for a second hypoglycemic clamp. Glucose kinetics were determined by three-tritiated glucose, and muscle sympathetic nerve activity (MSNA) was measured by microneurography.

RESULTS—Despite identical hypoglycemia (2.9 ± 0.1 mmol/l) and insulinemia during all clamp studies, key ANS (epinephrine, norepinephrine, and MSNA but not symptoms), neuroendocrine (cortisol), and metabolic (endogenous glucose production, glycogenolysis, and lipolysis) responses were increased (P < 0.01) following fluoxetine.

CONCLUSIONS—This study demonstrated that 6 weeks’ administration of the SSRI fluoxetine can amplify a wide spectrum of ANS and metabolic counterregulatory responses during hypoglycemia in healthy individuals. These data further suggest that serotonergic transmission may be an important mechanism in modulating sympathetic nervous system drive during hypoglycemia in healthy individuals.
Plasmacytoid Precursor Dendritic Cells From NOD Mice Exhibit Impaired Function
Authors: Huang Yiming , Fugier-Vivier Isabelle J. , Miller Thomas , Elliott Mary J. , Xu Hong , Bozulic Larry D. , Chilton Paula M. , Ildstad Suzanne T.
Published: June 2008

OBJECTIVE—Plasmacytoid precursor dendritic cell facilitating cells (p-preDC FCs) play a critical role in facilitation of syngeneic and allogeneic hematopoietic stem cell (HSC) engraftment. Here, we evaluated the phenotype and function of CD8+/TCR− FCs from NOD mice.

RESEARCH DESIGN AND METHODS—The phenotype of CD8+/TCR− FCs was analyzed by flow cytometry using sorted FCs from NOD, NOR, or B6 mice. The function of NOD FCs was evaluated by colony-forming cell (CFC) assay in vitro and syngeneic or allogeneic HSC transplantation in vivo.

RESULTS—We report for the first time that NOD FCs are functionally impaired. They fail to facilitate engraftment of syngeneic and allogeneic HSCs in vivo and do not enhance HSC clonogenicity in vitro. NOD FCs contain subpopulations similar to those previously described in B6 FCs, including p-preDC, CD19+, NK1.1+DX5+, and myeloid cells. However, the CD19+ and NK1.1+DX5+ subpopulations are significantly decreased in number in NOD FCs compared with disease-resistant controls. Removal of the CD19+ or NK1.1+DX5+ subpopulations from FCs did not significantly affect facilitation. Notably, Flt3 ligand (FL) treatment of NOD donors expanded FC total in peripheral blood and restored facilitating function in vivo.

CONCLUSIONS—These data demonstrate that NOD FCs exhibit significantly impaired function that is reversible, since FL restored production of functional FCs in NOD mice and suggest that FL plays an important role in the regulation and development of FC function. FCs may therefore be linked to diabetes pathogenesis and prevention.
Occupation-Related Differences in the Prevalence of Metabolic Syndrome
Authors: Sánchez-Chaparro Miguel-Angel , Calvo-Bonacho Eva , González-Quintela Arturo , Fernández-Labandera Carlos , Cabrera Martha , Sáinz Juan-Carlos , Fernández-Meseguer Ana , Banegas José R. , Ruilope Luis-Miguel , Valdivielso Pedro , Román-García Javier ,   on behalf of the Ibermutuamur Cardiovascular Risk Assessment (ICARIA) Study Group
Published: June 2008

OBJECTIVE—To investigate the prevalence of metabolic syndrome in the Spanish working population and determine how the prevalence varies according to occupation and sex.

RESEARCH DESIGN AND METHODS—This was a cross-sectional study of 259,014 workers (mean age 36.4 years, range [16–74]; 72.9% male) who underwent a routine medical checkup. The Adult Treatment Panel III (2001) definition for metabolic syndrome was used.

RESULTS—The prevalence of metabolic syndrome was 11.6% (95% CI 11.5–11.7) in male subjects and 4.1% (4.0–4.2) in female subjects and increased with age. The prevalence of metabolic syndrome varied in the different categories of occupational activity depending on the sex considered. Among female subjects, the age-adjusted prevalence of metabolic syndrome was higher in blue-collar than in white-collar workers, but this difference was not evident among male workers.

CONCLUSIONS—The prevalence of metabolic syndrome varies in the different categories of occupational activity in the Spanish working population. This variation also depends on sex.
Mathematical model of light propagation through liquid crystal display working under real conditions
Authors: Olifierczuk M.
Published: June 2008

The main aim of our work is to present a theory of light propagation through a liquid crystal display worked out in our University. This theory takes into account real conditions of a display operation such as temporal coherence of light source, interference phenomena, spectral characteristics of refractive coefficients of individual layers and their complex forms, real directions of ordinary and extraordinary wavevectors into each layer, real directions of light polarization into anisotropic or dichroic layers etc. Therefore, our theory can be used to determine optical parameters of a liquid crystal display operating under real or at least quasi-real conditions. Contrary to other theories (e.g., Beremann or geometric optics approximation), this model is characterized by a small number of simplifications. Thus, it can be used to analyse a display operating in special conditions, such as military or out-door applications. In these cases, very high optical parameters (luminance and contrast ratio) aare needed. Application of even small simplifications conducts to significant changes of calculated parameters.
Allogeneic hematopoietic stem cell transplantation for Epstein–Barr virus‐associated T/natural killer‐cell lymphoproliferative disease in Japan
Authors: Sato Emiko , Ohga Shouichi , Kuroda Hiroshi , Yoshiba Fumiaki , Nishimura Miki , Nagasawa Masayuki , Inoue Masami , Kawa Keisei
Published: June 2008

Epstein–Barr virus (EBV)‐associated T/NK‐cell lymphoproliferative disease (LPD) has been linked to several different disorders. Its prognosis is generally poor and a treatment strategy has yet to be established. There are reports, however, that hematopoietic stem cell transplantation (HSCT) can cure this disease. To clarify the current situation regarding allogeneic hematopoietic stem cell transplantation (allo‐HSCT) for EBV‐associated T/NK‐LPD, a nationwide survey was performed in Japan. Data for 74 patients were collected. There were 42 cases of chronic active EBV infection (CAEBV), 10 cases of EBV‐associated hemophagocytic lymphohistiocytosis (EBV‐HLH), and 22 cases of EBV‐associated lymphoma/leukemia (EBV‐lymphoma/leukemia). Of those with CAEBV, 54% had the EBV‐infected T‐cell type and 59% with EBV‐lymphoma/leukemia had the EBV‐infected NK‐cell type. Most patients with EBV‐HLH and EBV‐lymphoma/leukemia received allo‐HSCT within 1 year after onset compared to only 14% of patients with CAEBV. The event‐free survival (EFS) rate following allo‐HSCT was 0.561 ± 0.086 for CAEBV, 0.614 ± 0.186 for EBV‐HLH, and 0.309 ± 0.107 for EBV‐lymphoma/leukemia. The EFS of allo‐HSCT with conventional conditioning was 0.488 ± 0.074 and with reduced‐intensity conditioning was 0.563 ± 0.124. Thus, in a substantial number of cases, EBV‐associated T/NK‐LPD can be cured by either allogeneic conventional stem cell transplantation or reduced‐intensity stem cell transplantation. © 2008 Wiley‐Liss, Inc. Am. J. Hematol., 2008.
Risk of cognitive impairment in female premutation carriers of fragile X premutation: Analysis by means of robust segmented linear regression models
Authors: Mínguez Mónica , Ibáñez Berta , Ribate Maria‐Pilar , Ramos Feliciano , García‐Alegría Eva , Fernández‐Rivas Aránzazu , Ruiz‐Parra Eduardo , Poch Marisa , Alonso Angel , Martinez‐Bouzas Cristina , Beristain Elena , Tejada Maria‐Isabel
Published: June 2008

This report describes a study focused on the relationship between CGG repeat length, FMRP, mRNA levels and cognitive functioning in premutation carriers (PM) carriers of Fragile X Syndrome (FXS). We studied 60 females—43 with PM and 17 with normal (N) alleles—from 25 FXS Spanish families. The Wechsler scales were administered to all subjects and new blood samples and hair roots were taken to study mRNA and FMRP levels. Using lowess curves together with segmented models we showed that within the premutation range, IQ scores tend to decrease when the number of CGG repeats increases and the FMRP values decrease. Furthermore, we discovered cut‐off points in the molecular variables that seem to change the probability of having some cognitive impairment. Specifically, for those PM females in the upper premutation range (CGG ≥ 100) and with FMRP expression < 60% in hair roots, a 10% decrement of FMRP expression represents a significant decrease in IQ scores of about six points, which is more evident for Full‐Scale IQ (P‐value = 0.035) and Performance IQ (P‐value = 0.045) than for Verbal IQ (P‐value = 0.074). On the contrary, we did not find any significant correlation between FMR1 mRNA levels and the IQ scores, probably due to the fact that mRNA levels were measured in blood. In conclusion, our findings suggest that the PM can have some effect on cognitive ability in female carriers, although these effects may be subtle. In these cases, it would be advisable to carry out a hair root analysis of FMRP. © 2008 Wiley‐Liss, Inc.
Pharmacogenetics of methylphenidate response in attention deficit/hyperactivity disorder: Association with the dopamine transporter gene (SLC6A3)
Authors: Purper‐Ouakil D. , Wohl M. , Orejarena S. , Cortese S. , Boni C. , Asch M. , Mouren M.C. , Gorwood P.
Published: June 2008

Pharmacogenetic studies investigating the 40‐bp VNTR polymorphism at SLC6A3 and methylphenidate response have shown conflicting results and large differences in study design and efficacy endpoints. Our objective was to investigate the relation between the 3′‐VNTR at SLC6A3 and variability in methylphenidate response in a sample of 141 ADHD children and adolescents, assessed before and after methylphenidate treatment with both clinical and neuropsychological outcome measures. 10‐R homozygotes were significantly overrepresented in the low response group, but no genotype effect was shown in cognitive variables improvement. A meta‐analysis of pharmacogenetic studies with comparable data (responders vs. non‐responders) on a total of 475 subjects showed a significant association between the 10‐10 genotype and low rates of methylphenidate response (mean Odds Ratio = 0.46; 95% CI [0.28–0.76]). Heterogeneity between these studies did not reach a significant level but, as publications with different endpoints were excluded from this meta‐analysis, our results do not rule out a possible influence of study design. © 2008 Wiley‐Liss, Inc.
Surfactant‐Free Nonaqueous Synthesis of Metal Oxide Nanostructures
Authors: Pinna Nicola , Niederberger Markus
Published: June 2008

Surfactant‐free nonaqueous (and/or nonhydrolytic) sol–gel routes constitute one of the most versatile and powerful synthesis methodologies for nanocrystalline metal oxides with high compositional homogeneity and purity. Although the synthesis protocols are particularly simple, involving only metal oxide precursors and common organic solvents, the obtained uniform nanocrystals exhibit an immense variety of sizes and shapes. The small number of reactants in these routes enables the study of the chemical mechanisms involved in metal oxide formation. Nonhydrolytic routes to inorganic nanomaterials that used surfactants as size‐ and shape‐controlling agents have been discussed recently. This Minireview supplements this topic by discussing surfactant‐free processes, which have become a valuable alternative to surfactant‐assisted as well as to traditional aqueous sol–gel chemistry routes.
Synthesis of charged ultrafiltration poly(styrene‐ co‐divinyl benzene) composite membrane
Authors: Sachdeva Sonny , Kumar Anil
Published: June 2008

A ceramic supported crosslinked polystyrene composite membrane has been prepared from its monomers using a dual initiator system. The nonionic hydrophobic membrane so prepared has been chemically modified by a low temperature (50°C), single step reaction with chloroacetic acid. The carboxylated membrane has acid functional groups on its surface making it negatively charged and highly hydrophilic in nature. The membranes (unmodified and carboxylated) have been used for the separation of hazardous chromium (VI) salt solution where observed and intrinsic rejection has been studied as a function of pressure and concentration of the feed solution. The intrinsic rejection has been determined by calculating the concentration at the membrane surface (Cm) using Speigler‐Kedam model and osmotic pressure model. The observed rejection for the chemically modified membrane decreases with increasing pressure but the intrinsic rejection is found to be more than 80% for all concentrations in the range of study. The experimental results have been fitted using Space‐Charge model to obtain the membrane wall potential and the membrane surface concentration which are difficult to measure directly. The transport through the membrane capillaries has been described by the two dimensional model using Nernst‐Planck equation for ion transport, Navier‐Stokes equation and Poisson‐Boltzmann equation for the radial distribution of potential. We have then presented a semianalytical series solution to the highly nonlinear Poisson‐Boltzmann equation to reduce the computational time required to solve the set of coupled differential equations. The effective wall potential of the carboxylated membrane was found to be −28.07 mV. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Molecular characterization of a novel patched‐related protein in Apis mellifera and Drosophila melanogaster
Authors: Pastenes Luis , Ibáñez Freddy , Bolatto Carmen , Pavéz Leonardo , Cambiazo Verónica
Published: June 2008

The molecular identification and characterization of the patched‐related (ptr) gene and protein in Apis mellifera and Drosophila melanogaster are reported. Ptr proteins are closely related in predicted topology and domain organization to the protein encoded by the Drosophila segment polarity gene patched. Ptrs have 12 potential transmembrane domains arranged in two sets of 1+5 membrane‐spanning segments containing a conserved sterol‐sensing domain (SSD) and functional GxxxD and PPXY motifs. Phylogenetic analysis showed that Ptrs belong to a previously uncharacterized class of insect proteins that share a high level of sequence identity. Analysis using quantitative real‐time polymerase chain reaction (qPCR) indicates that ptr gene is preferentially expressed during embryo stages of A. mellifera development; interestingly, this pattern of temporal expression was also observed for the D. melanogaster homologue, suggesting that these proteins might be involved in embryo morphogenesis. To understand Ptr function at the molecular level, we investigated the subcellular distribution of DmPtr. We have shown by biochemical analysis that DmPtr protein is tightly associated with membranes. Consistently, Ptr immunoreactivity appears to be localized at the sites of membrane furrow formation during cellularization of D. melanogaster embryos. These studies indicated that Ptrs belong to a previously uncharacterized class of insect transmembrane proteins that share a high level of sequence identity. Our analysis of ptr gene expression and protein localization suggest that Ptr might fulfil a developmental role by participating in processes that require growth and stabilization of plasma membrane. Arch. Insect Biochem. Physiol. 68:156–170, 2008. © 2008 Wiley‐Liss, Inc.
Seeding density modulates migration and morphology of rabbit chondrocytes cultured in collagen gels
Authors: Khoshfetrat Ali Baradar , Kino‐oka Masahiro , Takezawa Yasunori , Yamamoto Takeyuki , Sugawara Katsura , Taya Masahito
Published: June 2008

The cultures of rabbit chondrocytes embedded in collagen gels were conducted to investigate the cell behaviors and consequent architectures of cell aggregation in an early culture phase. The chondrocyte cells seeded at 1.0 × 105 cells/cm3 underwent a transition to spindle‐shaped morphology, and formed the loose aggregates with a starburst shape by means of possible migration and gathering. These aggregates accompanied the poor production of collagen type II, while the cells seeded at 1.6 × 106 cells/cm3 exhibited active proliferation to form the dense aggregates rich in collagen type II. Stereoscopic observation was performed at 5 days to define the migrating cells in terms of a morphology‐relating parameter of sphericity determined for individual cells in the gels. The frequency of migrating cells decreased with increasing seeding density, while the frequency of dividing cells showed the counter trend. The culture seeded at 1.0 × 105 cells/cm3 gave the migrating cell frequency of 0.25, the value of which was 25 times higher than that at 1.6 × 106 cells/cm3. In addition, the analysis of mRNA expression revealed that the chondrocyte cells seeded at 1.0 × 105 cells/cm3 showed appreciable down‐regulation in collagen type II relating to differentiation and up‐regulation in matrix metalloproteinases relating to migration, as compared to the cells seeded at 1.6 × 106 cells/cm3. These data supports the morphological analyses concerning the cell migration and aggregate formation in the cultures with varied seeding densities. It is concluded that the seeding density is an important factor to affect the cell behaviors and architecture of aggregates and thereby to modulate the quality of cultured cartilage. © 2008 Wiley Periodicals, Inc. Biotechnol. Bioeng. 2009;102: 294–302. © 2008 Wiley Periodicals, Inc.
Postoperative medical complications are the main cause of early death after emergency surgery for colonic cancer
Authors: Iversen L H , Bülow S , Christensen I J , Laurberg S , Harling H
Published: June 2008

Background

Only a few small studies have evaluated risk factors related to early death following emergency surgery for colonic cancer. The aim of this study was to identify risk factors for death within 30 days after such surgery.

Methods

Some 2157 patients who underwent emergency treatment for colonic cancer from May 2001 to December 2005 were identified from the national colorectal cancer registry. Thirty-day mortality rates were calculated and risk factors for early death were identified using logistic regression analysis.

Results

The overall 30-day mortality rate was 22·1 per cent. The strongest risk factor for early death was postoperative medical complications (cardiopulmonary, renal, thromboembolic and infectious), with an odds ratio of 11·7 (95 per cent confidence interval 8·8 to 15·5). Such complications occurred in 24·4 per cent of patients, of whom 57·8 per cent died. Other independent risk factors were age at least 71 years, male sex, American Society of Anesthesiologists grade III or more, palliative outcome, tumour perforation, splenectomy and adverse intraoperative surgical events. Postoperative surgical complications were noted in 20·4 per cent of the patients but had no statistically significant influence on mortality.

Conclusion

Emergency surgery for colonic cancer is still associated with an increased risk of death. There is a need for a system providing increased safety in the perioperative period.
An EXAFS Spectroscopic, Large‐Angle X‐Ray Scattering, and Crystallographic Study of Hexahydrated, Dimethyl Sulfoxide and Pyridine 1‐Oxide Hexasolvated Mercury(II) Ions
Authors: Persson Ingmar , Eriksson Lars , Lindqvist‐Reis Patric , Persson Per , Sandström Magnus
Published: June 2008

The structure of the solvated mercury(II) ion in water and dimethyl sulfoxide has been studied by means of large‐angle X‐ray scattering (LAXS) and extended X‐ray absorption fine structure (EXAFS) techniques. The distribution of the HgO distances is unusually wide and asymmetric in both solvents. In aqueous solution, hexahydrated [Hg(OH2)6]2+ ions in a distorted octahedral configuration, with the centroid of the HgO distance at 2.38(1) Å, are surrounded by a diffuse second hydration sphere with Hg⋅⋅⋅OII distances of 4.20(2) Å. In dimethyl sulfoxide, the six HgO and Hg⋅⋅⋅S distances of the hexasolvated [Hg{OS(CH3)2}6]2+ complex are centered around 2.38(1) and 3.45(2) Å, respectively. The crystal structure of hexakis(pyridine 1‐oxide)mercury(II) perchlorate has been redetermined. The space group R$\bar 3$ implies six equal HgO distances of 2.3416(7) Å for the [Hg(ONC5H5)6]2+ complex at 100 K. However, EXAFS studies of this compound, and of the solids hexaaquamercury(II) perchlorate and hexakis(dimethyl sulfoxide)mercury(II) trifluoromethanesulfonate, also with six equidistant HgO bonds according to crystallographic results, reveal in all cases strongly asymmetric HgO distance distributions. Vibronic coupling of valence states in a so‐called pseudo‐Jahn–Teller effect probably induces the distorted configurations.
Highly Convenient Amine‐Free Sonogashira Coupling in Air in a Polar Mixed Aqueous Medium by trans‐ and cis‐[(NHC)2PdX2] (X=Cl, Br) Complexes of N/O‐Functionalized N‐Heterocyclic Carbenes
Authors: Ray Lipika , Barman Samir , Shaikh Mobin M. , Ghosh Prasenjit
Published: June 2008

Two new trans‐ and cis‐[(NHC)2PdX2] (X=Cl, Br) complexes of N/O‐functionalized N‐heterocyclic carbenes employed in a highly convenient amine‐free Sonogashira cross‐coupling reaction in air in a polar mixed aqueous medium are reported. Specifically, the trans‐[{1‐benzyl‐3‐(3,3‐dimethyl‐2‐oxobutyl)imidazol‐2‐ylidene}2PdBr2] (3) and cis‐[{1‐benzyl‐3‐(N‐tert‐butylacetamido)imidazol‐2‐ylidene}2PdCl2] (4) complexes effectively catalyzed the Sonogashira cross‐coupling reaction of aryl iodides with substituted acetylenes in air in a mixed solvent (DMF/H2O, 3:1 v/v) under amine‐free conditions. Interestingly, these trans‐ and cis‐[(NHC)2PdX2] (X=Cl, Br) complexes, with two N‐heterocyclic carbene ligands, exhibited superior activity compared with the now popular PEPPSI (pyridine enhanced precatalyst preparation, stabilization and initiation)‐themed analogues, trans‐[(NHC)Pd(pyridine)X2] (X=Cl, Br), 3 a and 4 a, with one N‐heterocyclic carbene ligand and a “throw away” pyridine ligand in a trans disposition to each other. The higher activities of 3 and 4 compared with PEPPSI analogues 3 a and 4 a are attributed to more‐electron‐rich metal centers, as revealed by DFT studies, in the former complexes and is in concurrence with a more electron‐rich metal center being effective in facilitating the oxidative addition of aryl halide, often a rate‐determining step in palladium‐mediated cross‐coupling reactions. Complexes 3 and 4 were prepared from the corresponding silver analogues by transmetalation with [(cod)PdCl2], whereas the corresponding PEPPSI analogues 3 a and 4 a were obtained directly from the imidazolium halide salts by reaction with PdCl2 in pyridine in the presence of K2CO3 as base.
Feasibility Study of New Limestone Flue Gas Desulfurization Process
Authors: Shengyu Liu , Wende Xiao , Pei Liu , Zhixiang Ye
Published: June 2008

A new method based on conventional limestone flue gas desulfurization (FGD) has been developed. The main difference compared to the conventional wet FGD is the utilization of granular limestone with acetic acid additives as the absorbent, which should save on the power required for pulverization of limestone and pumping the circulation slurry. This paper focuses on a feasibility study of the new limestone FGD process by comparing SO2 removal efficiency, SO2 absorption rate, limestone utilization and FGD system stability of the new FGD with those of the conventional FGD, in the same absorption equipment under the same experimental conditions. The results show that when the coarse limestone slurry (–80+100 mesh, US standard) is used directly as the absorbent, its utilization and SO2 removal efficiency, are very low at 44 and 60.7%, respectively. When the mixed slurry, which is composed of coarse limestone and 10–30 mmol/L acetic acid absorbs SO2, the degree of desulfurization is increased to 95% and the limestone utilization is enhanced to 93.5%. Finally, for the absorbent consisting of a fine limestone slurry (–300 mesh), the desulfurization efficiency and limestone utilization are 88 and 92.9%, respectively, under the same operating conditions. Therefore, the new desulfurization process is shown to be very feasible.