bluuebunny/crossref_metadata_2025 huggingface dataset:
A new rat model for vulnerability to epilepsy and autism spectrum disorders
Authors: Gilby Krista L.
Published: November 2008

Summary

Tremendous concern has arisen in response to the recent diagnostic outbreak of childhood developmental disorders, particularly involving attention deficit hyperactivity disorder (ADHD) and the autism spectrum disorders (ASD). Interestingly, similarities in clinical presentation across these disorders may suggest common predisposing factors. For instance, though not widely recognized, an increased predisposition toward seizure is a symptom that is very often associated with ADHD and ASD. Accordingly, a rat strain naturally bred to be seizure‐prone simultaneously developed behavioral and physical characteristics analogous to those observed in ADHD/ASD patients. These rats also show early signs of aberrant lipid handling, which is another symptom common to human patients with these disorders. As such, this rat strain could serve as an excellent model system through which to identify common pathophysiological events that constitute a“spectrum of vulnerability”toward ADHD/ASD and epilepsy.
Targeting energy metabolism in brain cancer with calorically restricted ketogenic diets
Authors: Seyfried Thomas N. , Kiebish Michael , Mukherjee Purna , Marsh Jeremy
Published: November 2008

Summary

Information is presented on the calorically restricted ketogenic diet (CRKD) as an alternative therapy for brain cancer. In contrast to normal neurons and glia, which evolved to metabolize ketone bodies as an alternative fuel to glucose under energy‐restricted conditions, brain tumor cells are largely glycolytic due to mitochondrial defects and have a reduced ability to metabolize ketone bodies. The CRKD is effective in managing brain tumor growth in animal models and in patients, and appears to act through antiangiogenic, anti‐inflammatory, and proapoptotic mechanisms.
UCP‐mediated free fatty acid uncoupling of isolated cortical mitochondria from fasted animals: Correlations to dietary modulations
Authors: Davis Laurie M. , Rho Jong M. , Sullivan Patrick G.
Published: November 2008

Summary

Uncoupling proteins (UCP) translocate protons from the mitochondrial intermembrane space to the matrix, thereby “uncoupling” electron transport from the production of ATP. It has been shown that these proteins are highly expressed in animals maintained on the ketogenic diet (KD). Although the exact mechanism remains unclear, it is known that these proteins are activated within a protective antireactive oxygen species (ROS) mechanism by free fatty acids (FFA). In our current studies, mitochondrial samples were probed for the presence of UCP2, which is the most ubiquitously expressed UCP isoform. We found that both traumatic brain injury and fasting upregulated the expression of UCP2, with a synergistic upregulation in fasted injured animals. We then used mitochondria from fasted naive animals to screen a number of FFA for their activation of uncoupling as well as their ability to reduce ROS. We found that arachidonic acid (AA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), palmitoleic acid, myristic acid, and butyric acid increased mitochondrial uncoupling when added after oligomycin. These FFA, along with oleic acid, also reduced ROS in mitochondria incubated with oligomycin. In order to correlate our data to KD and fasting, both of which have been shown to be neuroprotective after neurologic insult, we determined the serum levels of FFA in KD and fasted animals using gas chromatography/mass spectroscopy. We also determined brain and cerebrospinal fluid (CSF) FFA levels from fasted animals.
The ketogenic diet in a pill: Is this possible?
Authors: Rho Jong M. , Sankar Raman
Published: November 2008

Summary

Over the past decade, much progress has been made in understanding the mechanisms of ketogenic diet (KD) action. From the complex systemic and metabolic changes induced by the KD have emerged innovative hypotheses attempting to link biochemical adaptations to its clinical effects. Despite such developments, the fundamental question of how the KD works remains as elusive as ever. At present, it is unclear which of the many potential mechanisms proposed thus far are directly relevant to the clinical effects of the KD. It is unlikely that these numerous hypotheses can be unified into a single mechanism (or a final common pathway). Nevertheless, it may be instructive to consider each of these putative mechanisms in turn and ask the following question: if the mechanism or target in question is a critical determinant of the anticonvulsant efficacy of the KD, then would a similar intervention known to be based on that mechanism yield a comparable effect? Perhaps answering this question for each mechanistic speculation might help substantiate (or invalidate) that particular hypothesis. Can the KD be packaged into a pill? At present, the answer is likely “no.” We have yet to discover a “magic bullet” that completely mirrors the anticonvulsant (and potential neuroprotective) effects of the KD. However, without a clearer understanding of the mechanistic elements comprising the complex metabolic puzzle posed by the KD, we would be left only with empiric observations, and to wonder curiously how a high‐fat diet can exert such profound clinical effects.
Intermittent Wound Perfusion for Postoperative Pain Relief Following Upper Abdominal Surgery: A Surgeon's Perspective
Authors: Sistla Sarath Chandra , Sibal Amul Kumar , Ravishankar M.
Published: November 2008

Background:  Although there are many methods for postoperative pain management, implementation may be limited in some settings due to practical or financial constraints. Simple, inexpensive and easily implemented analgesic methods may improve access to effective pain relief.

Methods:  Fifty patients undergoing truncal vagotomy and gastrojejunostomy for pyloric stenosis secondary to chronic duodenal ulceration were studied in this prospective randomized trial. Subjects were assigned to receive either wound perfusion with 8 mL of 0.25% bupivacaine every 5 hours through a catheter placed subcutaneously or intravenous pethidine 0.2 mg/kg on demand for postoperative pain relief. Postoperative pain scores at rest were measured by visual analog scale and the opioid requirement at 0–12 hours, at 12–24 hours and at 24–36 hours were compared. Changes in respiratory parameters were also compared between the two groups.

Results:  Pain scores at 0–12 hours were significantly lower in the wound perfusion group compared with the intravenous pethidine group (5.7 ± 1.3 vs. 4.3 ± 1.2, mean ± SD; P < 0.001). The number of doses of analgesic required in the wound perfusion group was significantly lower compared with the controls during the 36 hours of study (3.5 ± 1.3 vs. 1.4 ± 1.0, P < 0.001). There were no differences in respiratory parameters, vital capacity, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and peak expiratory flow rate between the two groups. The FEV1 : FVC ratio, however, was significantly higher in the intravenous pethidine group. There were no wound complications due to catheter placement or systemic toxicity due to the anesthetic.

Conclusion:  Intermittent wound perfusion with 0.25% bupivacaine is a safe and efficient method to reduce pain scores and opioid requirement in the early postoperative period. Wound perfusion, however, had no beneficial effect on the postoperative respiratory function.
A Comparison of Egg Consumption with Other Modifiable Coronary Heart Disease Lifestyle Risk Factors: A Relative Risk Apportionment Study
Authors: Barraj Leila , Tran Nga , Mink Pamela
Published: November 2008

Guidelines from the American Heart Association (AHA) recommend that healthy adults limit their intake of dietary cholesterol to less than 300 mg per day. Since a large egg contains about 71% of that amount, the AHA recommends restricting egg consumption unless dietary cholesterol intakes from other sources are limited. We applied a risk apportionment approach to estimate the contribution of egg consumption and other modifiable lifestyle risk factors (e.g., smoking, poor diet, minimal exercise, and alcohol intake) to coronary heart disease (CHD) risk at the population level. Specifically, we categorized the U.S. adult population ages 25+ into distinct risk groups based on the prevalence of modifiable lifestyle risk factors and applied an apportionment model, typically used to assess risk contribution at the individual level, to estimate the contribution of egg intake to CHD risk. Our analysis shows that the combination of modifiable lifestyle risk factors accounts for less than 40% of the population CHD mortality. For the majority of U.S. adults age 25+, consuming one egg a day accounts for <1% of CHD risk. Hence, focusing on decreasing egg intake as an approach to modify CHD risk would be expected to yield minimal results relative to changing other behaviors such as smoking and other dietary habits.
Resource Allocation in Integrated Preoperational and Operational Management of Natural Hazards
Authors: Minciardi Riccardo , Sacile Roberto , Trasforini Eva
Published: November 2008

The management of natural hazards occurring over a territory entails two main phases: a preoperational—or pre‐event—phase, whose objective is to relocate resources closer to sites characterized by the highest hazard, and an operational—during the event—phase, whose objective is to manage in real time the available resources by allocating them to sites where their intervention is needed. Obviously, the two phases are closely related, and demand a unified and integrated treatment. This work presents a unifying framework that integrates various decisional problems arising in the management of different kinds of natural hazards. The proposed approach, which is based on a mathematical programming formulation, can support the decisionmakers in the optimal resource allocation before (preoperational phase) and during (operational phase) an emergency due to natural hazard events. Different alternatives of modeling the resources and the territory are proposed and discussed according to their appropriateness in the preoperational and operational phases. The proposed approach can be applied to the management of any natural hazard and, from an integration perspective, may be particularly useful for risk management in civil protection operations. An application related to the management of wildfire hazard is presented.
Fabrication of Nanocomposite Ceramics by Crystallization of Rapidly Solidified Eutectic Melts
Authors: Sakamoto Naonori , Araki Shunji , Yoshimura Masahiro
Published: November 2008

Eutectic melt solidification is shown to avoid cracking during solidification by quenching an amorphous phase. Subsequent annealing results in micro/nanostructure ceramics. This strategy has been applied to HfO2–Al2O3–GdAlO3 and Y2O3–CaO–Al2O3 ternary systems that have deep eutectics. In most cases, ceramic materials cracks when they are solidified from melt due to the thermal stress accumulated on the grain boundaries, the large specific volume difference between the melt and the crystalline solid, etc. The main reason why this strategy works is that a eutectic composition yields an amorphous phase from the melts by rapid cooling and the amorphous phase enables to design crystallization without cracking by postannealing. Appropriate postannealing for the quenched amorphous enables to control the crystallization behavior from the amorphous phase, which yields nanostructured composites without cracking. For the HfO2–Al2O3–GdAlO3 case, the melt solidification and postannealing yields a nanocomposite with high transparency due to reduced scattering of 5–10 nm crystallites. For the Y2O3–CaO–Al2O3 case, a plate‐shaped bulk composite is obtained without cracking by molding the melt and postannealing.
Control of Interface Properties in Oxide Composites Via Fugitive Coatings
Authors: Weaver Jared H. , Yang James , Zok Frank W.
Published: November 2008

Long‐term durability of ceramic composites requires the retention of weak interfaces to promote crack deflection and subsequent sliding at the fiber–matrix boundary. The present article addresses the efficacy of fugitive carbon coatings in achieving this goal in all‐oxide systems. A solution precursor route with a low‐temperature pyrolysis treatment has been devised and implemented for coating oxide fibers within a woven cloth. The coating is oxidized following completion of matrix processing to produce an interfacial gap. Upon comparing the mechanical properties of two continuous fiber ceramic composites—with and without a fugitive coating—the gap is shown to reduce the interfacial sliding resistance and significantly enhance the fracture resistance of the composite. It also enables an extension in the useful life of the composite when subjected to long‐term (1000 h) exposure at high temperature (1200°C). The results also suggest that modifications in the coating thickness may provide additional enhancement in composite durability.
Low‐Temperature Growth of Rutile Nanorod Thin Films and their Photon‐Induced Property
Authors: Wu Jin‐Ming , Qi Bin
Published: November 2008

Thin films of well‐crystallized pure rutile nanorods were deposited on Ti substrates through a simple solution approach at a low temperature of 353 K. Field emission scanning electron microscopic and atomic force microscopic investigations revealed topographies of both quasi‐aligned and less‐aligned nanorod arrays, depending on Ti grain facets. X‐ray diffraction and Raman spectra analysis verified that the deposited nanorod thin film was phase‐pure rutile. This rutile nanorod was identified to be single crystalline growing along the [001] direction by high‐resolution transmission electron microscopy. UV‐Vis diffuse reflectance spectra estimated a remarkable red shift in responsive light for the nanorods when compared with that of bulk rutile. Under illumination of artificial solar light, the ability of the rutile nanorod film to aid photodegradation of rhodamine B in water was argued to be superior to the rutile nanoparticles isolated from commercial Degussa P25, which was attributed to the unique rod‐like nanostructure.
Designing Precursors for Geopolymer Cements
Authors: Duxson Peter , Provis John L.
Published: November 2008

This paper presents a discussion of the ability to design raw materials for use in geopolymers. To provide a “green” material to complement existing cement binders, as well as in the interests of waste beneficiation, various potential means of tailoring geopolymer precursor chemistry and particle behavior are outlined. The opportunities presented by the development of one‐part “just add water” geopolymer formulations are identified as exceeding the potential of the traditional two‐part (solid plus alkaline activator solution) mix design. The key roles played by network‐modifying (alkali and alkaline earth) cations and alumina in rendering glassy phases “ideal” for geopolymerization are discussed, and the potential value of ASTM Class C ashes in synthesis of high‐performance geopolymers becomes evident. This provides a significant step toward the development of international standards for the application of geopolymer binders in the construction industry worldwide, and raises a number of important challenges for researchers in the field of geopolymer and cement technology.
Transparent MgAl2O4Spinel from a Powder Prepared by Flame Spray Pyrolysis
Authors: Goldstein Adrian , Goldenberg Ayala , Yeshurun Yehoshua , Hefetz Meir
Published: November 2008

The densification of an MgAl2O4spinel powder prepared by flame spray pyrolysis was examined in order to determine whether it is suitable for fabricating transparent parts using a sinter/HIP approach. It was found that the powder exhibits excellent sinterability. Firing pressed powder compacts to 1650°C/2 h in air increases the bulk density to 99.9% TD. Similar densification, within the precision range of He picnometry, but a higher level of light transmission, is obtained by firing for 80 h at 1400°C. By HIPing, both specimens, sintered at 1650° and 1400°C, are made transparent but the level of transparency attained is higher in the case of specimens presintered according to the latter conditions. Such specimens (2 mm thick) exhibit, after HIPing at 1500°C/3 h (Ar, 200 MPa), a real in‐line transmission (RIT) of 63% (635 nm), an average grain size of 2.2 μm, and a hardness of 13.2 GPa. After HIPing at 1700°C, the RIT attains a value of 77%, while the average grain increases to 17 μm and the Vickers hardness slightly decreases to 12.8 GPa.
Anelastic Behavior of Plasma‐Sprayed Zirconia Coatings
Authors: Liu Yajie , Nakamura Toshio , Dwivedi Gopal , Valarezo Alfredo , Sampath Sanjay
Published: November 2008

Low‐temperature thermal cycling of plasma‐sprayed zirconia coatings reveals unique mechanical responses in their curvature measurements, namely nonlinear and cyclic hysteresis, collectively termed as anelastic. These features arise from the inherent layered, porous, and cracked morphology of thermal‐sprayed ceramic materials. In this paper, the mechanisms of anelasticity are characterized by crack closure and frictional sliding models, and stress–strain relations of various thermal‐sprayed zirconia coatings were determined via an inverse analysis procedure. These results demonstrate process conditions such as powder morphology and spray parameters significantly influence the mechanical behaviors of coatings. The unique anelastic responses can be used as valuable parameters in identifying coating quality as well as process reliability in manufacturing.
Synthesis of Single‐Phase α‐Fe2O3 Nanopowders by Using A Novel Low Temperature Chemical Synthesis Route
Authors: Sarangi Prita Pant , Naik Bhanudas , Ghosh Narendra Nath
Published: November 2008

A simple aqueous solution‐based chemical methodology has been developed for the preparation of single‐phase α‐Fe2O3 nanopowder with average particle size ∼30 nm. Precursor powder was synthesized by reacting aqueous solutions of ferric nitrate with EDTA and then evaporating the resulting solution to dryness. The precursor was then calcined in air for 2.30 h at different temperatures ranging from 250° to 450°C. The synthesized powders were characterized by using thermogravimetric analysis‐differential scanning calorimetric analysis, X‐ray diffraction, Brunauer–Emmett–Teller surface area measurement, transmission electron microscopy, and scanning electron microscopy. DC electrical resistivity was measured by using the two‐probe method. Presence of pure α‐Fe2O3 nanophase was observed in precursor powder itself, which is the important feature of this method. The synthetic route described here provides a simple but cost‐effective method to produce single phase, α‐Fe2O3 nanopowders at a comparatively low temperature.
Manipulation of Porous Bioceramic Microstructures by Freezing of Suspensions Containing Binary Mixtures of Solvents
Authors: Rahaman Mohamed N. , Fu Qiang
Published: November 2008

In our previous work, using a unidirectional freeze‐casting method, it was observed that the addition of certain polar organic solvents, such as 1,4‐dioxane and glycerol, to aqueous suspensions of hydroxyapatite (HA) resulted in drastic changes to the microstructure. The objective of the present work is to provide a rationalization of the observed microstructures. Phase separation of the binary water–dioxane and water–glycerol mixtures during freezing, and the physical chemistry of the solvent mixtures, such as the ability of the polar organic solvents to modify the hydrogen bonding of water, are the key factors influencing the freeze‐cast microstructures. The porous HA constructs could be applied as scaffolds for bone repair.
The upregulation of cystatin C in human gingival fibroblasts stimulated with cyclosporine A
Authors: Tsai C.‐H. , Yang S.‐F. , Huang F.‐M. , Chang Y.‐C.
Published: November 2008

Background and Objective:  Cystatin C is a 13 kDa non‐glycosylated, basic protein belonging to the cystatin family. It is consistently and dramatically upregulated in a variety of fibrotic diseases. However, little is known about the correlation between cystatin C and cyclosporine A‐induced gingival overgrowth. The aim of this study was to compare cystatin C expression in normal, healthy gingival tissues and cyclosporine A‐induced gingival overgrowth specimens and further explore the potential mechanism that may result in cystatin C expression.

Material and Methods:  Fifteen cyclosporine A‐induced gingival overgrowth specimens and five normal gingival tissues were examined by immunohistochemistry. Three human gingival fibroblast (HGF) strains were established from crown‐lengthening surgery. The reverse transcriptase‐polymerase chain reaction was used to investigate the effects on HGFs exposed to cyclosporine A. In addition, predominant periodontal pathogens (Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis) and proinflammatory cytokines (interleukin‐1α and tumor necrosis factor‐α) were added to seek the possible regulatory mechanisms of cystatin C expression.

Results:  The cystatin C staining in gingival tissue was stronger in the cyclosporine A‐induced gingival overgrowth group than in the normal gingival group (p < 0.05). Intensive staining for cystatin C expression was observed mainly in the cytoplasm of fibroblasts, epithelial cells and inflammatory cells. Moreover, cystatin C expression was significantly higher in cyclosporine A‐induced gingival overgrowth specimens with higher levels of inflammatory infiltrates (p < 0.05). A concentration of 200 ng/mL cyclosporine A was found to increase cystatin C expression in HGFs in a time‐dependent manner (p < 0.05). The addition of periodontal pathogens and proinflammatory cytokines significantly increased the expression of cystatin C compared with cyclosporine A alone (p < 0.05).

Conclusion:  The increased ability of protein accumulation by cystatin C is one of several factors mediating cyclosporine A‐induced gingival overgrowth. In addition, cyclosporine A may predispose to gingival overgrowth in inflammatory environments.
The tumour microenvironment: a novel target for cancer therapy
Authors: Hanna E , Quick J , Libutti SK
Published: November 2008

Cancer therapy is in the midst of a major paradigm shift. Traditionally, cancer treatments have focused on tumour cells. However, studies over the past few decades have demonstrated that cancer is a vastly complex entity with multiple components affecting a tumour’s growth, invasion and metastasis. These components, collectively termed the ‘tumour microenvironment’, include endothelial cells, pericytes, fibroblasts, inflammatory cells, leucocytes and elements of the extracellular matrix (ECM). Biological agents that target components of the tumour microenvironment may provide an interesting alternative to traditional tumour cell‐directed therapy. Because of the complexity of the tumour milieu, the most beneficial therapy will likely involve the combination of one or more agents directed at this new target. This review highlights recent preclinical and clinical studies involving agents that target tumour vasculature, leucocytes, pericytes, cancer‐associated fibroblasts and ECM components. We pay particular attention to combination therapies targeting multiple components of the tumour microenvironment, and aim to demonstrate that this strategy holds promise for the future of cancer treatment.
Overexpression of cytokeratin 17 protein in oral squamous cell carcinoma in vitro and in vivo
Authors: Wei K‐J , Zhang L , Yang X , Zhong L‐P , Zhou X‐J , Pan H‐Y , Li J , Chen W‐T , Zhang Z‐Y
Published: November 2008

Objective:  To determine the cytokeratin 17 (CK17) expression in oral squamous cell carcinoma (OSCC) both in vitro and in vivo.

Methods:  Comparative proteomic analysis of an in vitro cellular carcinogenesis model of OSCC (including a line of human immortalized oral epithelia cells (HIOECs), a line of cancerous HB96 cells and another kind of cells (HB56 cells) at the early stage of carcinogenesis was performed to identify differentially expressed proteins. CK17 was further validated in vitro (cellular carcinogenesis model and other three OSCC lines) and in vivo (tissues from six healthy persons and 30 primary OSCC patients) by Western blotting and immunohistochemistry respectively.

Results:  Increased CK17 expression was identified by two‐dimensional gel electrophoresis and liquid chromatography–tandem mass chromatography in the HB56 and HB96 cells over HIOECs. Western blotting confirmed the increased CK17 expression in the HB56, HB96 cells and other three OSCC lines. Immunohistochemistry confirmed the increased CK17 expression in the cancerous tissues from OSCC patients compared with the paired adjacent non‐malignant epithelia.

Conclusion:  Increased CK17 expression may play an important role in the carcinogenesis progression of OSCC; however, further studies on the molecular function of CK17 are encouraged to clear the precise mechanism of CK17 in OSCC.
Polypyrimidine tract binding protein regulates alternative splicing of an aberrant pseudoexon in NF1
Authors: Raponi Michela , Buratti Emanuele , Llorian Miriam , Stuani Cristiana , Smith Christopher W. J. , Baralle Diana
Published: November 2008

In disease‐associated genes, understanding the functional significance of deep intronic nucleotide variants represents a difficult challenge. We previously reported that an NF1 intron 30 exonization event is triggered from a single correct nomenclature is ‘c.293‐279 A>G’ mutation [Raponi M, Upadhyaya M & Baralle D (2006) Hum Mutat 27, 294–295]. In this paper, we investigate which characteristics play a role in regulating inclusion of the aberrant pseudoexon. Our investigation shows that pseudoexon inclusion levels are strongly downregulated by polypyrimidine tract binding protein and its homologue neuronal polypyrimidine tract binding protein. In particular, we provide evidence that the functional effect of polypyrimidine tract binding protein is proportional to its concentration, and map the cis‐acting elements that are principally responsible for this negative regulation. These results highlight the importance of evaluating local sequence context for diagnostic purposes, and the utility of developing therapies to turn off activated pseudoexons.
Mycobacterium tuberculosis ClpC1
Authors: Kar Narayani P. , Sikriwal Deepa , Rath Parthasarathi , Choudhary Rakesh K. , Batra Janendra K.
Published: November 2008

Caseinolytic protein, ClpC is a general stress protein which belongs to the heat shock protein HSP100 family of molecular chaperones. Some of the Clp group proteins have been identified as having a role in the pathogenesis of many bacteria. The Mycobacterium tuberculosis genome demonstrates the presence of a ClpC homolog, ClpC1. M. tuberculosis ClpC1 is an 848‐amino acid protein, has two repeat sequences at its N‐terminus and contains all the determinants to be classified as a member of the HSP100 family. In this study, we overexpressed, purified and functionally characterized M. tuberculosis ClpC1. Recombinant M. tuberculosis ClpC1 showed an inherent ATPase activity, and prevented protein aggregation. Furthermore, to investigate the contribution made by the N‐terminal repeats of ClpC1 to its functional activity, two deletion variants, ClpC1Δ1 and ClpC1Δ2, lacking N‐terminal repeat I and N‐terminal repeat I along with the linker between N‐terminal repeats I and II, respectively were generated. Neither deletion affected the ATPase activity. However, ClpC1Δ1 was structurally altered, less stable and was unable to prevent protein aggregation. Compared with wild‐type protein, ClpC1Δ2 was more active in preventing protein aggregation and displayed higher ATPase activity at high pH values and temperatures. The study demonstrates that M. tuberculosis ClpC1 manifests chaperone activity in the absence of any adaptor protein and only one of the two N‐terminal repeats is sufficient for the chaperone activity. Also, an exposed repeat II makes the protein more stable and functionally more active.
UNDERWATER STOCK OPTIONS AND VOLUNTARY EXECUTIVE TURNOVER: A MULTIDISCIPLINARY PERSPECTIVE INTEGRATING BEHAVIORAL AND ECONOMIC THEORIES
Authors: DUNFORD BENJAMIN B. , OLER DEREK K. , BOUDREAU JOHN W.
Published: November 2008

In a study of top U.S. executives between 1996 and 2006, we examined the impact of underwater stock options on voluntary turnover. Financial and economic logic suggests that underwater options may carry a positive valuation based on Black–Scholes (BS) pricing, even when the current market price is below the exercise price. However, a variety of psychological and behavioral theories suggest that underwater option portfolios may motivate voluntary turnover to a greater extent than what can be captured by Black–Scholes valuation. Findings supported these perspectives, as underwater options were associated with voluntary executive turnover, after controlling for the BS value of the options and other factors. Moreover, we found evidence that voluntary turnover dynamics differed substantially between CEOs and non‐CEOs.
DEVELOPMENT ENGAGEMENT WITHIN AND FOLLOWING DEVELOPMENTAL ASSESSMENT CENTERS: CONSIDERING FEEDBACK FAVORABILITY AND SELF–ASSESSOR AGREEMENT
Authors: WOO SANG E. , SIMS CARRA S. , RUPP DEBORAH E. , GIBBONS ALYSSA M.
Published: November 2008

This study sought to understand employees' level of behavioral engagement in response to feedback received in developmental assessment center (DAC) programs. Hypotheses were drawn from theories of self‐enhancement and self‐consistency and from findings in the multisource feedback and assessment center literatures regarding recipients' perceptions of feedback. Data were gathered from 172 U.S. middle managers participating in a DAC program. Results suggested that more favorable feedback was related to higher behavioral engagement. When discrepancies between self‐ and assessor ratings were examined, overraters (participants whose overall self‐ratings were higher than their assessor ratings) tended to show less engagement in the program compared to underraters. However, pattern agreement on the participant's dimension profile did not significantly correlate with behavioral engagement. Based on these findings, avenues for future research are presented and practical implications are discussed.
THE ROLE OF JOB EMBEDDEDNESS ON EMPLOYEE PERFORMANCE: THE INTERACTIVE EFFECTS WITH LEADER–MEMBER EXCHANGE AND ORGANIZATION‐BASED SELF‐ESTEEM
Authors: SEKIGUCHI TOMOKI , BURTON JAMES P. , SABLYNSKI CHRIS J.
Published: November 2008

Although job embeddedness was originally conceptualized to explain job stability or “why people stay” in their organizations, this investigation examines the role of job embeddedness as a hypothesized moderator of relationships among leader–member exchange (LMX), organization‐based self‐esteem (OBSE), organizational citizenship behaviors (OCBs), and task performance. Findings from 2 studies involving 367 employees and 41 supervisors, 1 in a telecommunications company and another in a manufacturing setting, support hypotheses concerning job embeddedness as a moderator of the relationship between (a) LMX and task performance within a telecommunication sample and LMX and OCBs in a sample of manufacturing employees, and (b) OBSE and OCBs in a manufacturing sample. Further, a hypothesized 3‐way interaction involving job embeddedness, LMX, and OBSE on task performance was found in a sample of manufacturing employees. The implications of these findings for studying and managing job embeddedness in relation to employee performance are discussed.
HOW TRANSFORMATIONAL LEADERSHIP WEAVES ITS INFLUENCE ON INDIVIDUAL JOB PERFORMANCE: THE ROLE OF IDENTIFICATION AND EFFICACY BELIEFS
Authors: WALUMBWA FRED O. , AVOLIO BRUCE J. , ZHU WEICHUN
Published: November 2008

This study examined how transformational leadership directly and indirectly relates to supervisory‐rated performance collected over time including 437 participants employed by 6 U.S. banking organizations in the midwest. Results revealed that one's identification with his or her work unit, self‐efficacy, and means efficacy were related to supervisor‐rated performance. The effect of transformational leadership on rated performance was also mediated by the interaction of identification and means efficacy, as well as partially mediated by the interaction of self‐efficacy and means efficacy. Implications for research, theory, and practice are discussed.
INCREASED ACCURACY FOR RANGE RESTRICTION CORRECTIONS: IMPLICATIONS FOR THE ROLE OF PERSONALITY AND GENERAL MENTAL ABILITY IN JOB AND TRAINING PERFORMANCE
Authors: SCHMIDT FRANK L. , SHAFFER JONATHAN A. , OH IN‐SUE
Published: November 2008

A recently developed procedure produces substantial improvements in the accuracy of corrections for range restriction and reveals that predictive validities of employment selection methods are higher than previously thought. This study applied this procedure to meta‐analytic validities of 2 personality measures (Conscientiousness and Emotional Stability) and general cognitive ability measures. Results show that the increases in validity estimates are greater for cognitive ability than for personality, reducing the relative validity of personality. In addition, the incremental validity of these personality measures over that provided by cognitive ability is smaller than previously estimated. Path analyses based on the more accurate data reveal relatively smaller path coefficients from these personality traits to job and training performance. These findings have implications for theories of job performance and for the practical value in selection of personality measures relative to cognitive ability measures.
DEVELOPMENTS IN THE CRITERION‐RELATED VALIDATION OF SELECTION PROCEDURES: A CRITICAL REVIEW AND RECOMMENDATIONS FOR PRACTICE
Authors: VAN IDDEKINGE CHAD H. , PLOYHART ROBERT E.
Published: November 2008

The use of validated employee selection and promotion procedures is critical to workforce productivity and to the legal defensibility of the personnel decisions made on the basis of those procedures. Consequently, there have been numerous scholarly developments that have considerable implications for the appropriate conduct of criterion‐related validity studies. However, there is no single resource researchers can consult to understand how these developments impact practice. The purpose of this article is to summarize and critically review studies published primarily within the past 10 years that address issues pertinent to criterion‐related validation. Key topics include (a) validity coefficient correction procedures, (b) the evaluation of multiple predictors, (c) differential prediction analyses, (d) validation sample characteristics, and (e) criterion issues. In each section, we discuss key findings, critique and note limitations of the extant research, and offer conclusions and recommendations for the planning and conduct of criterion‐related studies. We conclude by discussing some important but neglected validation issues for which more research is needed.
Cost‐Effectiveness of a School‐Based Obesity Prevention Program
Authors: Wang Li Yan , Gutin Bernard , Barbeau Paule , Moore Justin B. , Hanes John , Johnson Maribeth H. , Cavnar Marlo , Thornburg Janet , Yin Zenong
Published: November 2008

BACKGROUND:  A school‐based obesity prevention study (Medical College of Georgia FitKid Project) started in the fall of 2003 in 18 elementary schools. Half of the schools were randomized to an after‐school program that included moderate‐to‐vigorous physical activity, healthy snacks, homework assistance, and academic enrichment. All third graders were invited to enroll. The objective of this study was to assess the cost‐effectiveness (CE) of the first‐year intervention.

METHODS:  Standard CE analysis methods and a societal perspective were used. Program delivery costs incurred during the first‐year intervention and the usual after‐school care costs that would occur in the absence of the intervention were estimated (in 2003 dollars). Net intervention costs were calculated by subtracting the usual after‐school care costs from the intervention costs. The effectiveness of the intervention was measured as percent body fat (%BF) reduction compared with a control condition. The CE was assessed as the net intervention cost divided by the effectiveness of the intervention.

RESULTS:  The intervention costs totaled $174,070, $558/student, or $956/student who attended ≥40% of the intervention sessions. The usual after‐school care costs were estimated at $639/student. Students who attended ≥40% of the intervention reduced %BF by 0.76% (95% confidence interval: −1.42 to −0.09) at an additional cost of $317/student.

CONCLUSIONS:  Subjects who attended ≥40% of the intervention achieved a significant reduction in %BF at a relatively low cost. School‐based obesity prevention programs of this type are likely to be a cost‐effective use of public funds and warrant careful consideration by policy makers and program planners.
A Statewide Movement to Promote the Adoption of Tobacco‐Free School Policies*
Authors: Summerlin‐Long Shelley K. , Goldstein Adam O.
Published: November 2008

BACKGROUND:  Since most tobacco users become addicted to nicotine as teenagers, prevention efforts for youth remain central to comprehensive prevention programs. National and state efforts that encourage adoption and enforcement of comprehensive tobacco‐free school (TFS) policies can lead to significant reductions of youth tobacco use. In 2003, North Carolina (NC) Health and Wellness Trust Fund grantees began to focus statewide on the adoption of and compliance with TFS policies in NC schools. This study examined 46 NC districts that passed TFS policies between 2003 and early August of 2005 to see what factors were important in policy passage in order to support the continued promotion of TFS policy adoption across the state.

METHODS:  Detailed interviews were conducted with 118 key informants who were intimately involved with passage of their school districts’ TFS policies, and results were coded and analyzed for common themes.

RESULTS:  The study found several strategies key to adoption of TFS policies: effective leadership from organizations and individuals in positions of influence, grassroots organizing from community coalitions and youth groups, and communication strategies that optimally position policy adoption and compliance.

CONCLUSION:  States that have not yet achieved TFS policy adoption can focus on leadership development, grassroots organizing, and improved communication to advance their advocacy efforts.
Kickin’ Asthma: School‐Based Asthma Education in an Urban Community
Authors: Magzamen Sheryl , Patel Bina , Davis Adam , Edelstein Joan , Tager Ira B.
Published: November 2008

BACKGROUND:  In urban communities with high prevalence of childhood asthma, school‐based educational programs may be the most appropriate approach to deliver interventions to improve asthma morbidity and asthma‐related outcomes. The purpose of this study was to evaluate the implementation of Kickin’ Asthma, a school‐based asthma curriculum designed by health educators and local students, which teaches asthma physiology and asthma self‐management techniques to middle and high school students in Oakland, CA.

METHODS:  Eligible students were identified through an in‐class asthma case identification survey. Approximately 10‐15 students identified as asthmatic were recruited for each series of the Kickin’ Asthma intervention. The curriculum was delivered by an asthma nurse in a series of four 50‐minute sessions. Students completed a baseline and a 3‐month follow‐up survey that compared symptom frequency, health care utilization, activity limitations, and medication use.

RESULTS:  Of the 8488 students surveyed during the first 3 years of the intervention (2003‐2006), 15.4% (n = 1309) were identified as asthmatic; approximately 76% of eligible students (n = 990) from 15 middle schools and 3 high schools participated in the program. Comparison of baseline to follow‐up data indicated that students experienced significantly fewer days with activity limitations and significantly fewer nights of sleep disturbance after participation in the intervention. For health care utilization, students reported significantly less frequent emergency department visits or hospitalizations between the baseline and follow‐up surveys.

CONCLUSIONS:  A school‐based asthma curriculum designed specifically for urban students has been shown to reduce symptoms, activity limitations, and health care utilization for intervention participants.
Local Ca2+ influx through CRAC channels activates temporally and spatially distinct cellular responses
Authors: Parekh A. B.
Published: November 2008

Ca2+ entry through store‐operated Ca2+ release‐activated Ca2+ (CRAC) channels controls a disparate array of key cellular responses. In this review, recent work will be described that shows local Ca2+ influx through CRAC channels has important spatial and temporal consequences on cell function. A localized Ca2+ rise below the plasma membrane activates, within tens of seconds, catabolic enzymes resulting in the generation of the intracellular messenger arachidonic acid and the paracrine pro‐inflammatory molecule LTC4. In addition, local Ca2+ entry can activate gene expression, which develops over tens of minutes. Local Ca2+ influx through CRAC channels therefore has far‐reaching consequences on intra‐ and intercellular communication.
Modulation of calcium signalling by intracellular organelles seen with targeted aequorins
Authors: Alonso M. T. , Manjarrés I. M. , García‐Sancho J.
Published: November 2008

The cytosolic Ca2+ signals that trigger cell responses occur either as localized domains of high Ca2+ concentration or as propagating Ca2+ waves. Cytoplasmic organelles, taking up or releasing Ca2+ to the cytosol, shape the cytosolic signals. On the other hand, Ca2+ concentration inside organelles is also important in physiology and pathophysiology. Comprehensive study of these matters requires to measure [Ca2+] inside organelles and at the relevant cytosolic domains. Aequorins, the best‐known chemiluminescent Ca2+ probes, are excellent for this end as they do not require stressing illumination, have a large dynamic range and a sharp Ca2+‐dependence, can be targeted to the appropriate location and engineered to have the proper Ca2+ affinity. Using this methodology, we have evidenced the existence in chromaffin cells of functional units composed by three closely interrelated elements: (1) plasma membrane Ca2+ channels, (2) subplasmalemmal endoplasmic reticulum and (3) mitochondria. These Ca2+‐signalling triads optimize Ca2+ microdomains for secretion and prevent propagation of the Ca2+ wave towards the cell core. Oscillatory cytosolic Ca2+ signals originate also oscillations of mitochondrial Ca2+ in several cell types. The nuclear envelope slows down the propagation of the Ca2+ wave to the nucleus and filters high frequencies. On the other hand, inositol‐trisphosphate may produce direct release of Ca2+ to the nucleoplasm in GH3 pituitary cells, thus providing mechanisms for selective nuclear signalling. Aequorins emitting at different wavelengths, prepared by fusion either with green or red fluorescent protein, permit simultaneous and independent monitorization of the Ca2+ signals in different subcellular domains within the same cell.
Roles of the actin‐binding proteins in intracellular Ca2+ signalling
Authors: Chun J. T. , Santella L.
Published: November 2008

Starfish oocytes undergo massive intracellular Ca2+ signalling during meiotic maturation and fertilization. Although the igniting stimulus of Ca2+ mobilization may differ in different cell contexts, its final leverage is usually the Ca2+‐releasing second messengers such as InsP3, cADPr and NAADP. The general scheme of intracellular Ca2+ release is that the corresponding receptors for these molecules serve as ion channels to release free Ca2+ from its internal stores such as the lumen of the endoplasmic reticulum. However, a growing body of evidence has suggested that intracellular Ca2+ release can be strongly modulated by the actin cytoskeleton. Although it is known that Ca2+ contributes to remodelling of the actin cytoskeleton, whether the actin cytoskeleton modulates Ca2+ signalling in return has not been much explored. An emerging candidate to answer to this reciprocal causality of Ca2+ and the actin cytoskeleton may be actin‐binding proteins. In this review, we discuss how the actin cytoskeleton may fit into the known mechanisms of intracellular Ca2+ release, and propose two models to explain the experimental data.
Physiological functions of glucose‐inhibited neurones
Authors: Burdakov D. , González J. A.
Published: November 2008

Glucose‐inhibited neurones are an integral part of neurocircuits regulating cognitive arousal, body weight and vital adaptive behaviours. Their firing is directly suppressed by extracellular glucose through poorly understood signalling cascades culminating in opening of post‐synaptic K+ or possibly Cl− channels. In mammalian brains, two groups of glucose‐inhibited neurones are best understood at present: neurones of the hypothalamic arcuate nucleus (ARC) that express peptide transmitters NPY and agouti‐related peptide (AgRP) and neurones of the lateral hypothalamus (LH) that express peptide transmitters orexins/hypocretins. The activity of ARC NPY/AgRP neurones promotes food intake and suppresses energy expenditure, and their destruction causes a severe reduction in food intake and body weight. The physiological actions of ARC NPY/AgRP cells are mediated by projections to numerous hypothalamic areas, as well as extrahypothalamic sites such as the thalamus and ventral tegmental area. Orexin/hypocretin neurones of the LH are critical for normal wakefulness, energy expenditure and reward‐seeking, and their destruction causes narcolepsy. Orexin actions are mediated by highly widespread central projections to virtually all brain areas except the cerebellum, including monosynaptic innervation of the cerebral cortex and autonomic pre‐ganglionic neurones. There, orexins act on two specific G‐protein‐coupled receptors generally linked to neuronal excitation. In addition to sensing physiological changes in sugar levels, the firing of both NPY/AgRP and orexin neurones is inhibited by the ‘satiety’ hormone leptin and stimulated by the ‘hunger’ hormone ghrelin. Glucose‐inhibited neurones are thus well placed to coordinate diverse brain states and behaviours based on energy levels.
Genetic manipulation, whole‐cell recordings and functional imaging of the sensorimotor cortex of behaving mice
Authors: Petersen C. C. H.
Published: November 2008

Sensory processing, sensorimotor integration and motor control are amongst the most basic functions of the brain and yet our understanding of how the underlying neuronal networks operate and contribute to behaviour is very limited. The relative simplicity of the mouse whisker sensorimotor system is helpful for detailed quantitative analyses of motor control and perception during active sensory processing. Recent technical advances now allow the measurement of membrane potential in awake‐behaving mice, using whole‐cell recordings and voltage‐sensitive dye imaging. With these recording techniques, it is possible to directly correlate neuronal activity with behaviour. However, in order to obtain causal evidence for the specific contributions of different neuronal networks to behaviour, it is critical to manipulate the system in a highly controlled manner. Advances in molecular neurobiology, gene delivery and mouse genetics provide techniques capable of layer, column and cell‐type specific control of gene expression in the mouse neocortex. Over the next years, we anticipate considerable advances in our understanding of brain function through measuring and manipulating neuronal activity with unprecedented precision to probe the molecular and synaptic mechanisms underlying simple forms of active sensory perception and associative learning.