bluuebunny/crossref_metadata_2025_split huggingface dataset:
The development of orientated symplectites during deformation
Authors: BRODIE K. H. 
Published: May 2007

Abstract
Orientated symplectites have been observed in deformed granulite facies metabasic rocks from the Ivrea‐Verbano zone in northern Italy. The area underwent lower crustal extension, accommodated by movement on localized high‐T shear zones. In areas of relatively low strain, such as at the margins of shear zones, symplectites of orthopyroxene, plagioclase and spinel have formed. The symplectites are vermiform and orientated parallel to the main foliation and in the regional stretching direction. The reaction was synkinematic with the deformation, and only developed in potentially dilatant grain boundaries in the rock. It was presumably inhibited in grain boundaries subjected to higher normal stress due to the relatively large volume increase involved in the reaction.The observations support the interpretation that the deformation was related to regional extension under high‐T granulite facies conditions, the symplectites forming as a result of decreasing pressure.
The Phe‐124‐Cys and A‐161T Variants of the Human 5‐HT1B Receptor Gene Are Not Major Determinants of the Clinical Response to Sumatriptan
Authors: Mehrotra Suneet , Vanmolkot Kaate R. J. , Frants Rune R. , Van Den Maagdenberg Arn M. J. M. , Ferrari Michel D. , MaassenVanDenBrink Antoinette 
Published: May 2007

Background.—The 5‐HT1B/1D receptor agonist sumatriptan is highly effective in the treatment of migraine. However, some patients do not respond to sumatriptan or experience recurrence of the headache after initial relief. In addition, some patients report chest symptoms after the use of sumatriptan.Objective.—To assess whether 2 genetic variants (F124C changing a phenylalanine for a cysteine and polymorphism A/T at nucleotide position ‐161 in the 5′ regulatory region) of the 5‐HT1B receptor play a major role in the therapeutic response to sumatriptan. The 5‐HT1B receptor most likely mediates the therapeutic action and coronary side effects of sumatriptan, and both F124C and A‐161T have relevant functional consequences on either the affinity of sumatriptan to bind to the 5‐HT1B receptor or on receptor expression level itself, respectively.Method.—Genomic DNA of a relatively small but very well‐characterized set of migraine patients with consistently good response to sumatriptan (n = 14), with no response (n = 12), with recurrence of the headache (n = 12), with chest symptoms (n = 13), and patients without chest symptoms (n = 27) was available for the genetic analyses and screened for the F124C variant and the A‐161T polymorphism in the human 5‐HT1B receptor gene.Results.—F124C was not detected in any of the patients studied. In addition, we did not observe drastic changes in allele frequencies of the A‐161T polymorphism that might hint to a causal relation with the therapeutic effect of sumatriptan.Conclusion.—We have not obtained any evidence that variants F124C and A‐161T of the 5‐HT1B receptor are major determinants in the clinical response to sumatriptan.
Cardiovascular Effects of Tibolone: A Selective Tissue Estrogenic Activity Regulator
Authors: Campisi Roxana , Marengo Fernando D. 
Published: May 2007

ABSTRACTTraditionally, it was accepted that long‐term hormone replacement therapy (HRT) has a cardiovascular beneficial effect in postmenopausal women with and without coronary artery disease (CAD). However, randomized trials in postmenopausal women have not shown any benefit in either primary or secondary prevention of cardiovascular events. Therefore, these findings have raised the question of whether traditional HRT (i.e., estrogen and progesterone) has a cardioprotective effect in women at risk for or with established CAD. Concerns about the use of conventional HRT have led to a search for alternatives. Tibolone is a synthetic compound with estrogenic, androgenic, and progestogenic properties that relieves climacteric symptoms and prevents postmenopausal bone loss. Tibolone possesses a tissue‐selective mechanism of action that differs from that of estrogen and/or progestogen. Unlike these compounds, tibolone's metabolites play a central role in its mode of action. Tibolone is widely used for HRT. However, its clinical impact on cardiovascular disease is still under study. The current review focuses on the effects of tibolone on the cardiovascular system and discusses clinical investigations with this compound in postmenopausal women.
ANALYSES OF EXPRESSED SEQUENCE TAGS FROM SARGASSUM BINDERI (PHAEOPHYTA)1
Authors: Wong Tony Kok‐Min , Ho Chai‐Ling , Lee Weng‐Wah , Rahim Raha Abd. , Phang Siew‐Moi 
Published: May 2007

Sargassum is a source for many metabolites, including alginic acid, alginates, sulfated fucoidans, pigments, oils, sterols, and mannitols. The present study is the first attempt to examine Sargassum binderi (Sonder) J. Agardh, a tropical brown seaweed, using an expressed sequence tag (EST) approach. Single‐pass 5′ sequencing of 2304 cDNA clones generated 1876 ESTs of good quality, from which 1270 tentative unique genes (TUGs) consisting of 991 singletons and 279 contigs were obtained. Approximately 39.5% of the TUGs from S. binderi showed significant matches to the existing data bases and were further divided into nine subcategories: metabolism (24.9%); transcription and translation (22.5%); cellular processes (7.2%); protein folding, sorting, and degradation (5.6%); signaling (2.8%); membrane and transport (3%); receptor (1.1%); other functions (4.2%); and unknown proteins (28.7%). The sequences were compared with ESTs from Laminaria digitata (Hudson) J. V. Lamour.
Stroke: A Randomized Trial of Exercise or Relaxation
Authors: Mead Gillian E. , Greig Carolyn A. , Cunningham Irene , Lewis Susan J. , Dinan Susie , Saunders David H. , Fitzsimons Claire , Young Archie 
Published: May 2007

OBJECTIVES: To determine the feasibility and effect of exercise training after stroke.DESIGN: Randomized exploratory trial comparing exercise training (including progressive endurance and resistance training) with relaxation (attention control).SETTING: Interventions were performed in a rehabilitation hospital.PARTICIPANTS: Sixty‐six independently ambulatory patients (mean age 72, 36 men) without significant dysphasia, confusion, or medical contraindications to exercise training who had completed their usual rehabilitation and had been discharged from hospital.INTERVENTION: Both interventions were held three times a week for 12 weeks. Up to seven patients attended each session.MEASUREMENTS: The Functional Independence Measure; Nottingham Extended Activities of Daily Living; Rivermead Mobility Index; functional reach; sit‐to‐stand; elderly mobility score; timed up‐and‐go; Medical Outcomes Study 36‐Item Short Form Questionnaire, version 2 (SF‐36); Hospital Anxiety and Depression Score; aspects of physical fitness (comfortable walking speed, walking economy, and explosive leg extensor power) were measured at baseline, immediately after interventions (3 months), and 7 months after baseline.RESULTS: The median number of intervention sessions attended was 36 (interquartile range (IQR) 30.00–36.75) for exercise and 36 (IQR 30.50–37.00) for relaxation. Adherence to the individual exercises ranged from 94% to 99%. At 3 months, role‐physical (an item in SF‐36), timed up‐and‐go, and walking economy were significantly better in the exercise group (analysis of covariance). At 7 months, role‐physical was the only significant difference between groups.CONCLUSION: Exercise training for ambulatory stroke patients was feasible and led to significantly greater benefits in aspects of physical function and perceived effect of physical health on daily life.
Faculty Development for the 21st Century: Lessons from the Society of General Internal Medicine–Hartford Collaborative Centers for the Care of Older Adults
Authors: Williams Brent C. , Weber Valerie , Babbott Stewart F. , Kirk Lynne M. , Heflin Mitchell T. , O'Toole Elizabeth , Schapira Marilyn M. , Eckstrom Elizabeth , Tulsky Asher , Wolf Andrew M. , Landefeld Seth 
Published: May 2007

In this review of a recent set of faculty development initiatives to promote geriatrics teaching by general internists, nontraditional strategies to promote sustained change were identified, included enrolling a limited number of “star” faculty, creating ongoing working relationships between faculty, and developing projects for clinical or education program improvement. External funding, although limited, garnered administration support and was associated with changes in individual career trajectories. Activities to enfranchise top leadership were felt essential to sustain change.Traditional faculty development programs for clinician educators are periodic, seminar‐based interventions to enhance teaching and clinical skills. In 2003/04 the Collaborative Centers for Research and Education in the Care of Older Adults were funded by the John A. Hartford Foundation and administered by the Society of General Internal Medicine. Ten academic medical centers received individual grants of $91,000, with required cost sharing, to develop collaborations between general internists and geriatricians to create sustained change in geriatrics clinical teaching and learning. Through written and structured telephone surveys, activities designed to foster sustainability at funded sites were identified, and the activities and perceived effects of funding at the 10 funded sites were compared with those of the 11 highest‐ranking unfunded sites.The experience of the Collaborative Centers supports the conclusion that modest, targeted funding can provide the credibility and legitimacy crucial for clinician educators to allocate time and energy in new directions. Key success factors likely include high intensity and duration, integration into career trajectories, integration into clinical programs, and activities to enfranchise institutional leadership.
Benefits of a blood donation archive repository: international survey of donor repository procedures and Scottish experiences
Authors: Franklin I.M. , Dow B.C. , Jordan A.D. 
Published: May 2007

BACKGROUND: The use of a donation sample archive has been in place within the Scottish National Blood Transfusion Service for almost 35 years but the advent of human immunodeficiency virus donor testing led to this archive being kept for an indefinite period. This article describes the uses made of our archive repository.STUDY DESIGN AND METHODS: Records of various potential transfusion transmission episodes were accessed and examined to assess the age of the archives investigated and the outcome of the investigations. Other uses of the archive repository were also investigated by reviewing the records of retrievals. The use of the archive to aid the interpretation of hepatitis C virus–indeterminate results was also conducted. Finally a global survey was performed to ascertain the temperature and length of storage used by various transfusion services.RESULTS: A 3‐year archive would have allowed for the investigation of 45 percent of cases (including all hepatitis B virus cases), while a 10‐year archive would have allowed for 90 percent of cases. Only 34 percent of cases were shown to be transfusion‐transmitted. Of 16 donors with c22‐indeterminate bands on recombinant immunoblot assay, 2 (12%) could have been classified as confirmed‐positive on the basis of their archive samples. A considerable proportion (41%) of the most recent requests for retrieval from the archive have been associated with the need to perform new mandatory tests for tissue donations at issue. Samples older than 3 years accounted for 25 percent of all samples retrieved. The global survey showed a variety of conditions in terms of both length and temperature of storage.CONCLUSION: The use of a donation archive has been shown to be extremely useful in the investigation of potential transfusion‐transmitted infections with most (66%) having no evidence of transfusion transmission. Although 90 percent of our cases could have been fully investigated with only a 10‐year archive, perhaps the future retention period of hospital records should be considered when determining the length of storage of current donation archive samples.
Clinic Overbooking to Improve Patient Access and Increase Provider Productivity*
Authors: LaGanga Linda R. , Lawrence Stephen R. 
Published: May 2007

ABSTRACTThe problem of patientno‐shows(patients who do not arrive for scheduled appointments) is significant in many health care settings, where no‐show rates can vary widely. No‐shows reduce provider productivity and clinic efficiency, increase health care costs, and limit the ability of a clinic to serve its client population by reducing its effective capacity. In this article, we examine the problem of no‐shows and propose appointment overbooking as one means of reducing the negative impact of no‐shows. We find that patient access and provider productivity are significantly improved with overbooking, but that overbooking causes increases in both patient wait times and provider overtime. We develop a new clinic utility function to capture the trade‐offs between these benefits and costs, and we show that the relative values that a clinic assigns to serving additional patients, minimizing patient waiting times, and minimizing clinic overtime will determine whether overbooking is warranted. From the results of a series of simulation experiments, we determine that overbooking provides greater utility when clinics serve larger numbers of patients, no‐show rates are higher, and service variability is lower. Even with highly variable service times, many clinics will achieve positive net results with overbooking. Our analysis provides valuable guidance to clinic administrators about the use of appointment overbooking to improve patient access, provider productivity, and overall clinic performance.
Improving Revenue Management Decision Making for Airlines by Evaluating Analyst‐Adjusted Passenger Demand Forecasts*
Authors: Mukhopadhyay Somnath , Samaddar Subhashish , Colville Glenn 
Published: May 2007

ABSTRACTTo maximize revenue, airline revenue management analysts (RMAs) attempt to protect the right number of seats for late‐booking, high‐revenue‐generating passengers from low‐valued leisure passengers. Simulation results in the past showed that a major airline can generate approximately $500 million per year through efficient RM operations. Accurate passenger demand forecasts are required, because reduced forecast error significantly improves revenue. RMAs often adjust the system forecasts to improve revenue opportunity. Analysis of system forecast performance and analyst adjustment is complex, because one must account for all unseen demands throughout the life of a flight. This article proposes a method to account for unseen demand and evaluate forecast performance (adjusted or unadjusted) through a forecast monitoring system. Initial results from one major airline's origin‐destination market data justify the value of RMA forecasting adjustments.
Why Do Firms Become Widely Held? An Analysis of the Dynamics of Corporate Ownership
Authors: HELWEGE JEAN , PIRINSKY CHRISTO , STULZ RENÉ M. 
Published: May 2007

ABSTRACTWe examine the evolution of insider ownership of IPO firms from 1970 to 2001 to understand how U.S. firms become widely held. A majority of these firms has insider ownership below 20% after 10 years. Stock market performance and liquidity play an extremely important role in ownership dynamics. Firms with stocks that are highly valued, are liquid, and have performed well experience large decreases in insider ownership and become widely held. Ownership also falls for low cash flow and high capital expenditures firms. Surprisingly, variables proxying for agency costs have limited success in explaining the evolution of insider ownership.
Reputation Effects in Trading on the New York Stock Exchange
Authors: BATTALIO ROBERT , ELLUL ANDREW , JENNINGS ROBERT 
Published: May 2007

ABSTRACTTheory suggests that reputations allow nonanonymous markets to attenuate adverse selection in trading. We identify instances in which New York Stock Exchange (NYSE) stocks experience trading floor relocations. Although specialists follow the stocks to their new locations, most brokers do not. We find a discernable increase in liquidity costs around a stock's relocation that is larger for stocks with higher adverse selection and greater broker turnover. We also find that floor brokers relocating with the stock obtain lower trading costs than brokers not moving and brokers beginning trading post‐move. Our results suggest that reputation plays an important role in the NYSE's liquidity provision process.
Participation Costs and the Sensitivity of Fund Flows to Past Performance
Authors: HUANG JENNIFER , WEI KELSEY D. , YAN HONG 
Published: May 2007

ABSTRACTWe present a simple rational model to highlight the effect of investors' participation costs on the response of mutual fund flows to past fund performance. By incorporating participation costs into a model in which investors learn about managers' ability from past returns, we show that mutual funds with lower participation costs have a higher flow sensitivity to medium performance and a lower flow sensitivity to high performance than their higher‐cost peers. Using various fund characteristics as proxies for the reduction in participation costs, we provide empirical evidence supporting the model's implications for the asymmetric flow‐performance relationship.
The Value of Corporate Risk Management
Authors: MACKAY PETER , MOELLER SARA B. 
Published: May 2007

ABSTRACTWe model and estimate the value of corporate risk management. We show how risk management can add value when revenues and costs are nonlinearly related to prices and estimate the model by regressing quarterly firm sales and costs on the second and higher moments of output and input prices. For a sample of 34 oil refiners, we find that hedging concave revenues and leaving concave costs exposed each represent between 2% and 3% of firm value. We validate our approach by regressing Tobin's q on the estimated value and level of risk management and find results consistent with the model.
Prolongation of Ventricular Refractoriness by Defibrillation Shocks May be Due to Additional Depolarization of the Action Potential
Authors: DILLON STEPHEN M. , MEHRA RAHUL 
Published: May 2007

Shock‐Induced Refractoriness Prolongation in Canines. Introduction: A comparison of the effects of shock timing and strength on the effective refractory periods (ERPs) of open chest canine hearts to the duration of depolarization in optically recorded action potentials from the rabbit heart was conducted in order to investigate the mechanism of ERP prolongation in the canine. Methods and Results: Studies were conducted in four open chest canines hearts and three isolated, perfused rabbit hearts. Shocks were applied during ventricular pacing and the strength and timing were varied. The shock voltage gradient was measured at the stimulating site used to assess the ERP in the canine and at the optical recording site in the rabbit. Shock voltage gradients ranged from 7.5 to 53 V/cm in the canine and 2 to 25 V/cm in the rabbit. Shock coupling intervals (CIs) were varied over a range of 15% to 105% of the control ERP (canine) and 10% to 115% of the control action potential duration (APD) (rabbit). Shocks prolonged the ERP in the canine and they caused an additional period of depolarization that prolonged the action potential in the rabbit. ERP and APD prolongation showed similar dependencies on the shock strength and CI: both increased with increasing shock strength and CI. Conclusion: ERP prolongation in the canine may be due to the same type of responses seen on the optically recorded action potentials in the rabbit. ERP prolongation by low‐strength shocks at long CIs in the canine may be due to graded responses and premature action potentials. ERP prolongation by high‐strength shocks over a range of CIs may be due to the additional depolarization time response that prolongs the action potential in rabbits. (J Cardiovasc Electrophysiol, Vol. 3, pp. 442–456. October 1992)
Activation of Guinea Pig Atrial Muscarinic K+ Channels by Nucleoside Triphosphates in the Absence of Acetylcholine
Authors: HEIDBÜCHEL HEIN , CALLEWAERT GEERT , VEREECKE JOHAN , CARMELIET EDWARD 
Published: May 2007

Atrial Muscarinic K+ Channel Activation. Introduction: We studied the possible association of a nucieoside diphosphate kinase (NDPK) to the atrial muscarinic receptor‐G proten‐K+ channel triad and its functional importance in the activation of muscarinic K channels under basal conditions, i.e., in the absence of acetylcholine (ACh). Methods and Results: We performed cell‐attached and inside‐out patch clamp experiments in single atrial cells isolated from guinea pig hearts. Muscarinic K+ channels in inside‐out patches can be fully activated in the absence of ACh and guanosine triphosphate (GTP), provided that adenosine triphosphate (ATP)‐Mg2 + is present at the intracellular side of the membrane. The K 50 for ATP and Mg2 + are 224 μM and 105 μ respectively. The activation by ATP‐ Mg2+ is the result of a phosphorylating reaction. Other nucleoside triphosphates (NTPs) such as ITP, GTP, UTP, and CTP can substitute for ATP, but their efficiency is lower than that of ATP. The NTP‐dependent activation can be explained by a membrane‐bound NDPK that directly phosphorylates GDP that is bound to the G protein, GK. This NDPK‐catalyzed transsphosphory lation to activate GK is distinct from the classical agonist‐induced GDP‐to‐GTP exchange. The ATP‐dependent activation can be blocked as a result of competition between different intracellular nucleotides for the binding sites on NDPK. Conclusion: Under physiological conditions and in the absence of ACh, tbe block by G nucleotides and ADP will prevent full activation of the channels by intracellular ATP (present in millimolar concentrations). However, sporadic transphosphorylation of G K‐bound GDP may contribute to tbe basal activity of the channels and hence to the basal K* conductance of atrial cells. (J Cardiovasc Electrophysiol, Vol. 3, pp. 457–473, October 1992)