bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of stroke volume estimation for non‐steady‐state and steady‐state graded exercise testing
Authors: Davis James A. , Sorrentino Kristin M. , Soriano April C. , Pham Patrick H.
Published: January 2005

The stroke volume (SV) during exercise is an important index of the heart's functional capacity. A new method has been developed for the non‐invasive estimation of exercise SV (SVex). It requires the determination of the slope for the oxygen uptake versus heart rate relationship in the steady state of graded exercise testing (GXT). The product of the slope and a constant (reciprocal of an assumed value of the arterial oxygen content) equals an estimated value for SVex. It was validated in a previous study using invasive measurements while subjects were performing steady‐state GXT. However, currently the most commonly used GXT protocols are non‐steady state, e.g. protocols with 1‐min increment durations. We tested the hypothesis that SVex is the same for steady‐state and non‐steady‐state GXT. A total of 30 subjects (15 males and 15 females) served as subjects for the study. Each subject performed two GXTs on different days with different increment durations – 1 and 4 min. Ventilation and gas exchange were measured with the Vacumed metabolic cart. For the male subjects, the mean (SD) SVex values for the 1‐ and 4‐min GXTs were 155·4 (39·5) and 134·6 (27·5) ml, respectively. The corresponding values for the female subjects were 151·6 (37·6) and 134·3 (36·4) ml. Paired t‐test analysis demonstrated that for both genders the mean SVex for the 1‐min GXT was significantly larger than the 4‐min GXT mean value (P<0·05). Hence, the commonly used 1‐min GXT does not yield the same values for SVex as the steady‐state GXT.
The temnospondyl amphibian Cyclotosaurus from the Upper Triassic of Poland
Authors: SULEJ T. , MAJER D.
Published: January 2005

Abstract:  A gap in the Late Triassic fossil record of the capitosaur amphibian Cyclotosaurus is filled by new material from lacustrine deposits at Krasiejów, Poland, corresponding in age to the Lehrberg Beds (late Carnian) of Germany. The skull of the Polish cyclotosaur is intermediate in several respects between that of Cyclotosaurus robustus from the middle Carnian Schilfsandstein of Germany and the younger C. mordax from the early Norian Stubensandstein. It shows a decrease in the width of the skull and in the degree of concavity of the posterior margin of the skull roof. The differences are significant enough to warrant erection of a novel species, the name Cyclotosaurus intermedius sp. nov. being proposed. The pectoral girdle, identified for the first time in Cyclotosaurus, suggests the genus was more fully adapted to an aquatic mode of life than was Paracyclotosaurus.
Early Permian (Asselian) brachiopods from Karakorum (Pakistan) and their palaeobiogeographical significance
Authors: ANGIOLINI LUCIA , BRUNTON HOWARD , GAETANI MAURIZIO
Published: January 2005

Abstract: Early Permian (Asselian) brachiopods collected from the Gircha Formation of western Karakorum (Pakistan) are described. They include Bandoproductus girchensis sp. nov., Kiangsiella sp. indet., Trigonotreta lyonsensis Archbold and Thomas, Trigonotreta larghii sp. nov., Spirelytha petaliformis (Pavlova), Punctospirifer afghanus Termier, Termier, de Lapparent and Marin, and ?Dielasma sp. indet. and belong to the Trigonotreta lyonsensis–Punctospirifer afghanus Assemblage Biozone, the oldest so far recovered from the Permian succession of Karakorum. The faunal succession of Karakorum records a significant biotic change from the Asselian to the Sakmarian, a shift in diversity and composition that is also recorded along most of the Gondwanan margin and Peri‐Gondwanan regions and that should be related to a major climatic change: the end of the Gondwanan glaciation. A palaeobiogeographical analysis has been performed by means of multivariate methods applying cluster and ordination analyses based on the Jaccard Coefficient and Simpson Index to a matrix consisting of the presence/absence of 23 brachiopod genera from seven geographical operational units from central Afghanistan to eastern Australia. The results suggest the occurrence of a single biotic province during the Asselian, the Indoralian Province, embracing all the faunal stations examined, as a consequence of the global cold phase related to the last pulse of the Gondwanan glaciation.
The relationship between job satisfaction and health: a meta-analysis
Authors: Faragher E B , Cass M , Cooper C L
Published: January 2005

Background:A vast number of published studies have suggested a link between job satisfaction levels and health. The sizes of the relationships reported vary widely. Narrative overviews of this relationship have been published, but no systematic meta-analysis review has been conducted.

Methods:A systematic review and meta-analysis of 485 studies with a combined sample size of 267 995 individuals was conducted, evaluating the research evidence linking self-report measures of job satisfaction to measures of physical and mental wellbeing.

Results:The overall correlation combined across all health measures was r = 0.312 (0.370 after Schmidt-Hunter adjustment). Job satisfaction was most strongly associated with mental/psychological problems; strongest relationships were found for burnout (corrected r = 0.478), self-esteem(r = 0.429), depression (r = 0.428), and anxiety(r = 0.420). The correlation with subjective physical illness was more modest (r = 0.287).

Conclusions:Correlations in excess of 0.3 are rare in this context. The relationships found suggest that job satisfaction level is an important factor influencing the health of workers. Organisations should include the development of stress management policies to identify and eradicate work practices that cause most job dissatisfaction as part of any exercise aimed at improving employee health. Occupational health clinicians should consider counselling employees diagnosed as having psychological problems to critically evaluate their work—and help them to explore ways of gaining greater satisfaction from this important aspect of their life.
Insomnia is more common among subjects living in damp buildings
Authors: Janson C , Norbäck D , Omenaas E , Gislason T , Nyström L , Jõgi R , Lindberg E , Gunnbjörnsdottir M , Norrman E , Wentzel-Larsen T , Svanes C , Jensen E J , Torén K
Published: January 2005

Background:Insomnia is a condition with a high prevalence and a great impact on quality of life. Little is known about the relation between and sleep disturbances and the home environment.

Aim:To analyse the association between insomnia and building dampness.

Methods:In a cross-sectional, multicentre, population study, 16 190 subjects (mean age 40 years, 53% women) were studied from Reykjavik in Iceland, Bergen in Norway, Umeå, Uppsala, and Göteborg in Sweden, Aarhus in Denmark, and Tartu in Estonia. Symptoms related to insomnia were assessed by questionnaire.

Results:Subjects living in houses with reported signs of building dampness (n = 2873) had a higher prevalence of insomnia (29.4v23.6%; crude odds ratio 1.35, 95% CI 1.23 to 1.48). The association between insomnia and different indicators of building dampness was strongest for floor dampness: “bubbles or discoloration on plastic floor covering or discoloration of parquet floor” (crude odds ratio 1.96, 95% CI 1.66 to 2.32). The associations remained significant after adjusting for possible confounders such as sex, age, smoking history, housing, body mass index, and respiratory diseases. There was no significant difference between the centres in the association between insomnia and building dampness.

Conclusion:Insomnia is more common in subjects living in damp buildings. This indicates that avoiding dampness in building constructions and improving ventilation in homes may possibly have a positive effect on the quality of sleep.
Haloacetic acids in drinking water and risk for stillbirth
Authors: King W D , Dodds L , Allen A C , Armson B A , Fell D , Nimrod C
Published: January 2005

Background:Trihalomethanes (THMs) occurring in public drinking water sources have been investigated in several epidemiological studies of fetal death and results support a modest association. Other classes of disinfection by-products found in drinking water have not been investigated.

Aims:To investigate the effects of haloacetic acid (HAA) compounds in drinking water on stillbirth risk.

Methods:A population based case-control study was conducted in Nova Scotia and Eastern Ontario, Canada. Estimates of daily exposure to total and specific HAAs were based on household water samples and questionnaire information on water consumption at home and work.

Results:The analysis included 112 stillbirth cases and 398 live birth controls. In analysis without adjustment for total THM exposure, a relative risk greater than 2 was observed for an intermediate exposure category for total HAA and dichloroacetic acid measures. After adjustment for total THM exposure, the risk estimates for intermediate exposure categories were diminished, the relative risk associated with the highest category was in the direction of a protective effect, and all confidence intervals included the null value.

Conclusions:No association was observed between HAA exposures and stillbirth risk after controlling for THM exposures.
A comparison of self-reported sickness absence with absences recorded in employers’ registers: evidence from the Whitehall II study
Authors: Ferrie J E , Kivimäki M , Head J , Shipley M J , Vahtera J , Marmot M G
Published: January 2005

Aim:To compare self-reported sickness absence days in the last 12 months with recorded absences from the employers’ registers for the same period.

Methods:Self-reported sickness absence data over the 12 months preceding baseline (1985–88) were compared with absence records from the employers’ registers over the same period for 2406 women and 5589 men, participants in the Whitehall II study of British civil servants. Associations with self-rated health, longstanding illness, minor psychiatric disorder, physical illness, and prevalent coronary heart disease at baseline were determined.

Results:In general, women reported less sickness absence over the last year than was recorded in the employers’ registers, while men, with the exception of those in the lower employment grades, reported more. Agreement between self-reported and recorded absence days decreased as the total number of days increased. After adjustment for employment grade and the average number of recorded and self-reported absence days, the total number of self-reported absence days was within two days of the recorded number of days for 63% of women and 67% of men. Associations between annual self-reported sickness absence days and self-rated health, longstanding illness, minor psychiatric disorder, physical illness, and prevalent coronary heart disease were as strong as those for recorded absence days.

Conclusion:These findings suggest that agreement between the annual number of self-reported and the annual number of recorded sickness absence days is relatively good in both sexes and that associations with health are equivalent for both measures.
Health of children working in small urban industrial shops
Authors: Nuwayhid I A , Usta J , Makarem M , Khudr A , El-Zein A
Published: January 2005

Aims:To explore associations between work status and multidimensional health indices in a sample of urban Lebanese children.

Methods:A cross-sectional survey was used to compare 78 male children (aged 10–17 years) working full time in small industrial shops, and a comparison group of 60 non-working male schoolchildren. All children lived and worked or studied in the poor neighbourhoods of three main Lebanese cities.

Results:Working children reported frequent abuses. They smoked and dated more than the comparison group. They also reported a higher number of injuries (last 12 months) and recent skin, eye, and ear complaints (last two weeks). Physical examination revealed more changes in their skin and nails, but no differences in height or weight compared to non-working group. A higher blood lead concentration was detected among working children, but no differences in haemoglobin and ferritin. No differences were noted between the two groups of children regarding anxiety, hopelessness, and self-esteem. The drawings of the working children, however, revealed a higher tendency to place themselves outside home and a wider deficit in developmental age when compared to non-working children.

Conclusion:Significant differences were found between working and non-working children with respect to physical and social health parameters, but differences were less with regard to mental health. Future research should focus on (1) more sensitive and early predictors of health effects, and (2) long term health effects. The generality of findings to other work settings in the developing world should also be tested.
Effect of different approaches to treatment of smoking as a potential confounder in a case–control study on occupational exposures
Authors: Richiardi L , Forastiere F , Boffetta P , Simonato L , Merletti F
Published: January 2005

Aim:To evaluate the effect of different approaches to treatment of smoking as a potential confounder in an occupational study of lung cancer.

Methods:Data were used from a case–control study on 956 men with lung cancer and 1253 population controls recruited in two northern Italian areas during 1990–1992. The risk of lung cancer associated with 11 selected job titles and eight selected industrial activities was estimated using seven different methods to treat smoking history. To evaluate the confounding effect of smoking, odds ratios obtained using the first six models were compared with estimates from the seventh and most complex model, in which cumulative tobacco consumption and time since cessation were considered.

Results:Although crude odds ratios for some of the occupational categories were biased by up to 25%, such bias decreased to less than 10% when a simple model including smoking status (never, ex-, current) was used.

Conclusions:In occupational studies on lung cancer risk, information on smoking status may allow satisfactory control of the potential confounding effect of the habit.
HYDROGEN-FREE DIAMOND-LIKE CARBON DEPOSITED BY A LAYER-BY-LAYER TECHNIQUE USING PECVD
Authors: JIANG JIN , CHUNG SUK JAE
Published: January 2005

We developed a hydrogen-free diamond like carbon (DLC) film by a novel deposition technique of a layer-by-layer technique using plasma enhanced chemical vapor deposition (PECVD) in which a repeated deposition of a thin DLC layer and subsequently CF 4 plasma treatment on its surface have been carried out. The electrical, optical and structural properties of the DLC films deposited depend on the CF 4 plasma exposure time. The hydrogen content is less than 1 at % when the CF4 plasma exposure time is 140s. Its emission current is much higher and stability is much improved compared with conventional DLC.N-type, hydrogen-free DLC could be obtained by N ion doping N2 gas-phase doping in the CF 4 plasma. The optimum [ N 2][ CH 4] flow rate was found to be 9% for the efficient electron emission, at which the onset-field was 7.2 V /μ. The nitrogen gas-phase doped hydrogen-free DLC coating on Mo tip field emitter arrays (FEAs) increased the electron emission current from 160μ A to 1.52 mA and improved the stability in electron emission current.
ULTRA-THIN FILM DEPOSITION AND CHARACTERISATION OF 10nm AMORPHOUS CARBON LAYERS FOR APPLICATIONS IN MAGNETIC STORAGE DEVICES
Authors: Mc Lauglin J. , Maguire P. , Ogwu A. , Lamberton R. , Zhao Jun Fu , Lemoine P.
Published: January 2005

The paper will present an overview of our latest results using various ultra-thin film amorphous carbon deposition techniques, and focus on first to grow studies, nano-characterisation of the electrical, mechanical and barrier properties associated with films grown on various substrate types applied to the magnetic recording industry. Although some of the characterisation is carried out on 10nm coatings, the nanomechanical measurements are performed on samples with thickness values between 30nm to 200nm. This overview of our work deals with PECVD deposition techniques and examines ultra-thin film growth on Si and Al 2 O 3: TiC substrates. Some results are presented on the functional benefits of doping a-C:H films with Silicon and Nitrogen. All the work is related to the ability to produce effective 3nm to 10nm overcoat layers for new magnetic recording applications.
TRIBOLOGICAL PROPERTIES OF ULTRATHIN a-C:H OVERCOAT ON A MAGNETIC HARD DISK
Authors: YAMAMOTO TAKAYUKI , TOYOGUCHI TAKASHI , HONDA FUMIHIRO
Published: January 2005

The durability of the carbon thin film on magnetic hard disk has become increasingly important due to the reduced head to disk spacing. Amorphous hydrogenated carbon (a-C: H) films formed by plasma chemical vapor deposition (p-CVD) show superior tribological properties on magnetic hard disk. We need p-CVD deposition system with hot filament plasma source and toluence as a precursor material. In this paper, the material characterization and the tribological properties of a few nonometers thick a-C:H films by p-CVD are discussed by using XPS and Raman scattering spectroscopy, and pin-on-disk sliding test.
THE EFFECTS OF DEFECTS ON THE ELECTRICAL PROPERTIES OF AMORPHOUS CARBON LAYER FORMED BY ION IMPLANTATION INTO CVD DIAMOND FILMS
Authors: SHOW YOSHIYUKI , SEKINE DAISUKE , ITO HIROKAZU , IZUMI TOMIO , IWASE MITSUO
Published: January 2005

Correlation between defects and electrical properties in an amorphous carbon layer, formed by ion implantation into diamond film, have been studied by ESR method. The ion implantation produced dense defect structures (carbon dangling bonds) in the surface layer and led the implanted layer to a low resistance, as the high-density defect introduced variable range hopping conduction. The variable range hopping conduction was observed even after annealing at 1000°C, because the high-density defect existed in the surface region.
EFFECT OF DISORDER ON THE ELECTRICAL PROPERTIES OF AMORPHOUS CONDUCTING CARBON FILMS: OBSERVANCE OF FIELD INDUCED METAL-INSULATOR TRANSITION?
Authors: MEENAKSHI V. , SUBRAMANYAM S. V.
Published: January 2005

In this work, the influence of disorder on the electrical properties (DC conductivity and Magnetoresistance) of amorphous conducting carbon films, prepared by the pyrolysis of Tetra chloro phthalic anhydride, is reported and discussed. The low temperature electrical properties are analyzed in terms of the various models developed for disordered electronic systems. The results indicate the possibility of a metal - insulator (M-I) transition, both as a function of preparation temperature and an external magnetic field.
STRAIN FIELDS IN DIAMONDLIKE AMORPHOUS CARBON
Authors: KELIRES P. C.
Published: January 2005

This paper reviews the fundamental ideas related to the concept of local atomic stresses and their application to the study of strain fields in ta-C. The calculations are based on Monte Carlo simulations within the empirical potential approach. We find that the stress distributions in ta-C are high inhomogeneous, both in the bulk as well as in the surface and interface regions. There is a close relationship between local stress and hybridization. The most probable stress state for fourfold sites is compression, while threefold sites prefer to be under tension. Local-atomic behavior dominates longer-ranged stress conditions. Interdiffusion following thermal annealing is an important factor for the reduction of compressive stress in ta-C films grown on silicon substrates.
FIELD EMISSION FROM CARBON FILMS GROWN BY THE CATHODIC ARC PROCESS
Authors: MILNE W. I. , ROBERTSON J. , SATYANARAYANA B. S. , HART A.
Published: January 2005

By using the catholic vacuum are deposition process, carbon films with variable sp3/ sp2bonding ratio can be deposited on a variety of substrates at room temperature. The morphology of the films can be varied from the mirror like smooth tetrahedrally bonded carbon (ta-C) films through nanocluster to fibrous type carbon by altering the deposition parameters. This paper reviews the work carried out on Field Emission from such carbon films and compares the results with those on nanocluster films prepared using supersonic cluster beams. Threshold fields as low as 1 V /μ m with emission site densities of up to 104-105/ cm2have been obtained.
CHARACTERIZATION OF ta-C AND GRANULAR Co-C FILMS PREPARED BY PULSED FILTERED VACUUM ARC DEPOSITION
Authors: WONG S. P. , WANG H. , KE N. , CHEUNG W. Y. , CHIAH M. F. , CHEN D. H. , LI Q. J. , LIU H. , ZHANG X. X.
Published: January 2005

A pulsed filtered vacuum are deposition system was used to prepare ta-C thin films and granular Co-C films. The ta-C films prepared at various substrate bias voltages were characterized using Raman spectroscopy and spectroscopic ellipsometry of which the results confirmed that these ta-C films exhibit high sp 3 fraction of over 80%. The composition of the granular Co-C films prepared by the same system was determined by non-Rutherford backscattering spectrometry. The properties of these Co-C Films, as deposited and after vacuum annealing at various temperatures, were studied using Raman spectroscopy, electrical measurements, magnetic measurements by a SQUID magnetometer, atomic force microscopy and magnetic force microscopy. It was found that the dependence of the Raman spectra of these films on annealing temperature was associated with the formation and dissociation of a cobalt carbide phase and the graphitization of amorphous carbon. The magnetic properties showed complicated composition and annealing temperature dependence. The optimum annealing temperature for the maximum coercivity was found to depend on the composition of the film. For a film of Co 65 C 35 after annealing at 623K in vacuum for one hour, the coercivity was measured to be 460 Oe at 300K and 1380 Oe at 3K. Clear MFM images of the domain structures were observed for films after annealing at sufficiently high temperature, showing that there was perpendicular magnetic anisotropy in these films. A nearly-temperature-independent electrical resistance in the range from 20K to 300K was also observed. A more detailed analysis indicated that the low temperature electrical transport is consistent with a theory for granular metal films.
ERRATA: PHOTOLUMINESCENCE PROPERTIES AND LOCAL STRUCTURE OF POLYMER-LIKE a-C:H FILMS
Authors: GODET C. , HEITZ T. , DRAVILLON B. , BOURÉE J. E.
Published: January 2005

In order to understand better the electronic properties of π-bonded materials, some optical and photoluminescence properties of amorphous carbon films have been investigated as a function of film density (0.9 to 1.7 g·cm-3). This study gives an overview of the radiative recombination properties in relation with local structure characterizations (in situ infrared ellipsometry and Raman spectroscopies) for a series of dual-plasma deposited polymer-like a-C:H films. Medium range topology has consequences in the hyperconjugation effects seen on infrared bands, as well as in optical and resonant Raman characteristics. Photoluminescence (PL) excitation spectroscopy reveals resonance features which are attributed to exciton-like electron-hole pairs in close Coulomb interaction. The PL efficiency shows a sharp quenching for densities above 1.3 g·cm-3 where a clear transition also occurs in the Raman "fingerprint". In addition, quantitative analysis of IR ellipsometry and Elastic Recoil Detection give evidence of a strong decrease of both the effective dynamical charge e*(C-H) and the bandwidth of sp3 C-H vibrations; this is interpreted as being a result of the increase of local strains in the carbon skeleton, meaning that matrix distortions already appear at H content values as high as 46 H at.% due to film densification. An expected consequence is the mixing between π and σ molecular orbitals and the enhancement of the dissociation rate of confined electron-hole pairs. PL quenching would thus result from both a decrease of exciton confinement and an increase of the density of accessible nonradiative centers.
TOWARD A PLUG-AND-PLAY APPROACH FOR ACTIVE POWER FACTOR CORRECTION
Authors: ZELTSER ILYA , BEN-YAAKOV SAM
Published: January 2005

The feasibility of producing a modular Active Power Factor Correction (APFC) system was studied analytically and experimentally. It is shown that the novel control scheme that does not need the sensing of the input voltage is highly compatible with the modular, plug-and-play concept. Modularity is achieved by aggregating practically all the electronics in an IC or hybrid unit that may also include the power switch. This unit plus a line rectifier, inductor and bus capacitor are all that it takes to form an APFC system. It is demonstrated that dynamic stability is assured by the proposed inherent robust control method. This plug-and-play solution will greatly simplify and reduce the cost of the design and manufacturing of APFC front ends.
SINGLE-STAGE SINGLE-SWITCHED RECTIFIER/REGULATOR WITH MAGNETIC COUPLED NONDISSIPATIVE SNUBBER
Authors: ROH CHUNG-WOOK , MOON GUN-WOO , YOUN MYUNG-JOONG
Published: January 2005

This paper presents a new single-stage single-switched forward converter with magnetic coupled nondissipative snubber, which gives good power factor correction (PFC), low current harmonic distortion, and tight output voltage regulation. The proposed converter features low switch current and voltage stresses, essential for the design of a single-stage power factor correction converter. The prototype shows that the IEC1000-3-2 requirements are met satisfactorily with nearly unity power factor. This proposed converter with magnetic coupled nondissipative snubber is particularly suited for power supply applications with low power level.
ANALYSIS AND EXPERIMENT OF A SINGLE-STAGE THREE-PHASE FULL-BRIDGE CONVERTER WITH INHERENT POWER FACTOR CORRECTION AND ISOLATED OUTPUT
Authors: HUANG NIANCI , HUANG SHAN , FAN MUWEN
Published: January 2005

A novel switching mode power supply (SMPS) with input/output isolation is presented, which compounds the three-phase power factor corrector (PFC) with a full bridge converter in a single-stage. It solves the problem of over-voltage on the DC link due to pseudo-phase-shifting control (PPSC) mode. Its operating principle and critical parameters are analyzed. Experiment results of an isolated 10 Kw prototype show that the power factor of the system is above 0.99 and the soft-switching mode reduces most of the EMI.
SURVEY OF STATE-OF-THE-ART TECHNOLOGIES FOR COMPUTER–NETWORK SERVER AC/DC POWER SUPPLIES
Authors: JOVANOVIĆ MILAN M.
Published: January 2005

Due to a continuously increasing power demand of computer–network server equipment, power supply manufacturers are faced with requirements for ac/dc server power supplies with significantly higher power densities. In this paper, circuit technologies and optimization techniques that are suitable for meeting these new power-density requirements are discussed. The focus of the paper is on single-phase, single-output ac/dc power supplies that are used to generate a dc-bus voltage in distributed power systems employed in high-end network servers and telecom systems.
LARGE-SIGNAL ANALYSIS AND SIMULATION OF A ZVT BOOST CONVERTER
Authors: GURUNATHAN RANGANATHAN , BHAT ASHOKA K. S.
Published: January 2005

Large-signal analysis of a zero-voltage transition (ZVT) boost converter is presented. The proposed ZVT converter uses an auxiliary circuit with two auxiliary switches both having ZVS. Analysis is used to study the converter behavior for step changes in input voltage and load using MATLAB. SPICE simulation results are presented to verify the theoretical results. It is shown that the main switch and auxiliary switches of the proposed converter maintains soft-switching for large-signal transients.
Heart Failure and Death After Myocardial Infarction in the Community
Authors: Bursi Francesca , Enriquez-Sarano Maurice , Nkomo Vuyisile T. , Jacobsen Steven J. , Weston Susan A. , Meverden Ryan A. , Roger Véronique L.
Published: January 2005

Background—

In case series, mitral regurgitation (MR) increased the risk of death after myocardial infarction (MI), yet the prevalence of MR, its incremental prognostic value over ejection fraction (EF), and its association with heart failure and death after MI in the community is not known.

Methods and Results—

The prevalence of MR and its association with heart failure and death were examined among 1331 patients within a geographically defined MI incidence cohort between 1988 and 1998. Echocardiography was performed within 30 days after MI in 773 patients (58%), and MR was present in 50% of cases, mild in 38%, and moderate or severe in 12%. Among patients with MR, a murmur was inconsistently detected clinically. After 4.7±3.3 years of follow-up, 109 episodes of heart failure and 335 deaths occurred. There was a graded positive association between the presence and severity of MR and heart failure or death. Moderate or severe MR was associated with a large increase in the risk of heart failure (relative risk 3.44, 95% CI 1.74 to 6.82,
P
<0.001) and death (relative risk 1.55, 95% CI 1.08 to 2.22,
P
=0.019) among 30-day survivors independent of age, gender, EF, and Killip class.

Conclusions—

In the community, MR is frequent and often silent after MI. It carries information to predict heart failure or death among 30-day survivors independently of age, gender, EF, and Killip class. These findings, which are applicable to a large community-based MI cohort, suggest that the assessment of MR should be included in post-MI risk stratification.
Role of Permanent Pacing to Prevent Atrial Fibrillation
Authors: Knight Bradley P. , Gersh Bernard J. , Carlson Mark D. , Friedman Paul A. , McNamara Robert L. , Strickberger S. Adam , Tse Hung Fat , Waldo Albert L.
Published: January 2005

This advisory summarizes the current database on pacing modalities and algorithms used to prevent and terminate atrial fibrillation (AF). On the basis of the evidence indicating that ventricular pacing is associated with a higher incidence of AF in patients with sinus node dysfunction, a patient who has a history of AF and needs a pacemaker for bradycardia should receive a physiological pacemaker (dual chamber or atrial) rather than a single-chamber ventricular pacemaker. For patients who need a dual-chamber pacemaker, efforts should be made to program the device to minimize the amount of ventricular pacing when atrioventricular conduction is intact. Many pacemakers and implantable defibrillators have features designed to prevent AF and to terminate AF with rapid atrial pacing. The evidence to support their use is limited, although these algorithms appear to be safe and usually add little additional cost. For patients who have a bradycardia indication for pacing and also have AF, no consistent data from large randomized trials support the use of alternative single-site atrial pacing, multisite right atrial pacing, biatrial pacing, overdrive pacing, or antitachycardia atrial pacing. Even fewer data support the use of atrial pacing in the management of AF in patients without symptomatic bradycardia. At present, permanent pacing to prevent AF is not indicated; however, additional studies are ongoing, which will help to clarify the role of permanent pacing for AF.
Patients With Depressive Symptoms Have Lower Health Status Benefits After Coronary Artery Bypass Surgery
Authors: Mallik Susmita , Krumholz Harlan M. , Lin Zhen Qiu , Kasl Stanislav V. , Mattera Jennifer A. , Roumains Sarah A. , Vaccarino Viola
Published: January 2005

Background—

Depression is an established independent prognostic factor for mortality, readmission, and cardiac events after CABG surgery. However, limited data exist on whether depression influences functional outcomes after CABG.

Methods and Results—

We followed 963 patients who underwent first CABG between February 1999 and February 2001. At baseline and at 6 months after CABG, we interviewed patients to assess depressive symptoms using the Geriatric Depression Scale (GDS) and physical function using the Short Form-36 Physical Component Scale (PCS). The patient’s physical function was considered improved if the PCS score increased ≥5 points at 6 months. Patients with high GDS scores were younger, were more often female, and had worse physical function and higher comorbidity than patients with low GDS scores. Rates of improvement in physical function were 60.1% for a GDS score <5 (below 75th percentile), 49.8% for a GDS score between 5 and 9 (75th to 90th percentile), and 39.7% for a GDS score ≥10 (≥90th percentile;
P
=0.002 for the trend). Depressive symptoms remained a significant independent predictor of lack of functional improvement after adjustment for severity of coronary artery disease, angina class, baseline PCS score, and medical history. A GDS score ≥10 was a stronger inverse risk factor for functional improvement after CABG than such traditional measures of disease severity as previous myocardial infarction, heart failure on admission, history of diabetes, and left ventricular ejection fraction.

Conclusions—

Higher levels of depressive symptoms at the time of CABG are a strong risk factor for lack of functional benefits 6 months after CABG.
Losartan Increases Bradykinin Levels in Hypertensive Humans
Authors: Campbell Duncan J. , Krum Henry , Esler Murray D.
Published: January 2005

Background—

Studies in animals and humans indicate a role for kinins in the actions of angiotensin type 1 (AT
1
) receptor blockers. However, the effect of these compounds on kinin levels in humans is unknown.

Methods and Results—

We measured angiotensin (Ang), bradykinin (BK), and kallidin peptides in subjects with essential hypertension administered placebo, losartan (50 mg OD), and eprosartan (600 mg OD) in randomized order in a double-blind, 3-period, 3-treatment, crossover trial. Peptides were measured in arterial blood using high-performance liquid chromatography–based radioimmunoassays. Losartan increased blood levels of BK-(1–9) and hydroxylated BK-(1–9) by ≈2-fold and reduced the BK-(1–7)/BK-(1–9) ratio by 55%. There was a trend for eprosartan to produce similar changes in bradykinin levels. There were no changes in blood kallidin levels. Both losartan and eprosartan increased plasma levels of Ang I, Ang II, and Ang-(2–8), and eprosartan increased Ang-(3–8) levels. Ang-(1–7) and Ang-(1–9) levels were unchanged. There was an associated 30% to 35% reduction in Ang II/Ang I ratio and 63% to 69% reduction in Ang-(1–7)/Ang I ratio. Plasma ACE activity was unchanged.

Conclusions—

Losartan increases bradykinin levels. The reductions in BK-(1–7)/BK-(1–9), Ang II/Ang I, and Ang-(1–7)/Ang I ratios suggest that the increased bradykinin levels were the result of reduced metabolism by ACE and neutral endopeptidase. Increased bradykinin levels may represent a class effect of AT
1
receptor blockers that contributes to their therapeutic actions and may also contribute to the angioedema that may accompany this therapy.
Irbesartan and Lipoic Acid Improve Endothelial Function and Reduce Markers of Inflammation in the Metabolic Syndrome
Authors: Sola Srikanth , Mir Muhammad Q.S. , Cheema Faiz A. , Khan-Merchant Nadya , Menon Rekha G. , Parthasarathy Sampath , Khan Bobby V.
Published: January 2005

Background—

The metabolic syndrome is associated with increased angiotensin II activity, induction of a proinflammatory and oxidative state, and endothelial dysfunction. We evaluated the ability of irbesartan, an angiotensin receptor blocker, and lipoic acid, an antioxidant, to affect endothelial function and inflammation in patients with the metabolic syndrome.

Methods and Results—

We randomized 58 subjects with the metabolic syndrome in a double-blinded manner to irbesartan 150 mg/d (n=14), lipoic acid 300 mg/d (n=15), both irbesartan and lipoic acid (n=15), or matching placebo (n=14) for 4 weeks. Endothelium-dependent and -independent flow-mediated vasodilation was determined under standard conditions. Plasma levels of interleukin-6, plasminogen activator-1, and 8-isoprostane were measured. After 4 weeks of therapy, endothelium-dependent flow-mediated vasodilation of the brachial artery was increased by 67%, 44%, and 75% in the irbesartan, lipoic acid, and irbesartan plus lipoic acid groups, respectively, compared with the placebo group. Treatment with irbesartan and/or lipoic acid was associated with statistically significant reductions in plasma levels of interleukin-6 and plasminogen activator-1. In addition, treatment with irbesartan or irbesartan plus lipoic acid decreased 8-isoprostane levels. No significant changes in blood pressure were noted in any of the study groups.

Conclusions—

Administration of irbesartan and/or lipoic acid to patients with the metabolic syndrome improves endothelial function and reduces proinflammatory markers, factors that are implicated in the pathogenesis of atherosclerosis.
Cholesteryl Ester Transfer Protein TaqIB Variant, High-Density Lipoprotein Cholesterol Levels, Cardiovascular Risk, and Efficacy of Pravastatin Treatment
Authors: Boekholdt S.M. , Sacks F.M. , Jukema J.W. , Shepherd J. , Freeman D.J. , McMahon A.D. , Cambien F. , Nicaud V. , de Grooth G.J. , Talmud P.J. , Humphries S.E. , Miller G.J. , Eiriksdottir G. , Gudnason V. , Kauma H. , Kakko S. , Savolainen M.J. , Arca M. , Montali A. , Liu S. , Lanz H.J. , Zwinderman A.H. , Kuivenhoven J.A. , Kastelein J.J.P.
Published: January 2005

Background—

Several studies have reported that the cholesteryl ester transfer protein (CETP)
TaqIB
gene polymorphism is associated with HDL cholesterol (HDL-C) levels and the risk of coronary artery disease (CAD), but the results are inconsistent. In addition, an interaction has been implicated between this genetic variant and pravastatin treatment, but this has not been confirmed.

Methods and Results—

A meta-analysis was performed on individual patient data from 7 large, population-based studies (each >500 individuals) and 3 randomized, placebo-controlled, pravastatin trials. Linear and logistic regression models were used to assess the relation between
TaqIB
genotype and HDL-C levels and CAD risk. After adjustment for study, age, sex, smoking, body mass index (BMI), diabetes, LDL-C, use of alcohol, and prevalence of CAD,
TaqIB
genotype exhibited a highly significant association with HDL-C levels, such that
B2B2
individuals had 0.11 mmol/L (0.10 to 0.12,
P
<0.0001) higher HDL-C levels than did
B1B1
individuals. Second, after adjustment for study, sex, age, smoking, BMI, diabetes, systolic blood pressure, LDL-C, and use of alcohol,
TaqIB
genotype was significantly associated with the risk of CAD (odds ratio=0.78 [0.66 to 0.93]) in
B2B2
individuals compared with
B1B1
individuals (
P
for linearity=0.008). Additional adjustment for HDL-C levels rendered a loss of statistical significance (
P
=0.4). Last, no pharmacogenetic interaction between
TaqIB
genotype and pravastatin treatment could be demonstrated.

Conclusions—

The CETP
TaqIB
variant is firmly associated with HDL-C plasma levels and as a result, with the risk of CAD. Importantly, this CETP variant does not influence the response to pravastatin therapy.
Vascular Endothelial Dysfunction and Mortality Risk in Patients With Chronic Heart Failure
Authors: Katz Stuart D. , Hryniewicz Katarzyna , Hriljac Ingrid , Balidemaj Kujtim , Dimayuga Clarito , Hudaihed Alhakam , Yasskiy Aleksandr
Published: January 2005

Background—

Endothelial function is known to be impaired in subjects with chronic heart failure (CHF), but the association between endothelial function and subsequent mortality risk in CHF has not been previously reported.

Methods and Results—

Biomarkers of endothelial function in the systemic arterial circulation (flow-mediated dilation [FMD] in the brachial artery) and the pulmonary circulation (exhaled nitric oxide [NO] production during submaximal exercise) were prospectively assessed in 259 subjects with New York Heart Association class II–III CHF. In subjects with FMD measurements (n=149), there were 12 deaths and 5 urgent transplantations over a median follow-up period of 841 days. In subjects with exhaled NO production measurements (n=110), there were 18 deaths and 1 urgent transplantation over a median follow-up period of 396 days. Both decreased FMD and decreased exhaled NO production were associated with increased risk of death or urgent transplantation after adjustment for other known CHF prognostic factors (age, etiology of CHF, functional class, left ventricular ejection fraction) in Cox multivariate proportional-hazards models (adjusted hazard ratio [HR] estimate for a 1% decrease in FMD=1.20; 95% confidence interval [CI], 1.03 to 1.45;
P
=0.027; adjusted HR estimate for a 1-ppb/min decrease in exhaled NO production=1.31, 95% CI, 1.01 to 1.69,
P
=0.04).

Conclusions—

Endothelial dysfunction in CHF, as assessed by FMD in the brachial artery and exhaled NO production during submaximal exercise, is associated with an increased mortality risk in subjects with both ischemic and nonischemic CHF.
Relationship of Late Loss in Lumen Diameter to Coronary Restenosis in Sirolimus-Eluting Stents
Authors: Mauri Laura , Orav E. John , O’Malley A. James , Moses Jeffrey W. , Leon Martin B. , Holmes David R. , Teirstein Paul S. , Schofer Joachim , Breithardt Günter , Cutlip Donald E. , Kereiakes Dean J. , Shi Chunxue , Firth Brian G. , Donohoe Dennis J. , Kuntz Richard E.
Published: January 2005

Background—

Observed rates of restenosis after drug-eluting stenting are low (<10%). Identification of a reliable and powerful angiographic end point will be useful in future trials.

Methods and Results—

Late loss (postprocedural minimum lumen diameter minus 8-month minimum lumen diameter) was measured in the angiographic cohorts of the SIRIUS (n=703) and E-SIRIUS (n=308) trials. Two techniques, the standard normal approximation and an optimized power transformation, were used to predict binary angiographic restenosis rates and compare them with observed restenosis rates. The mean in-stent late loss observed in the SIRIUS trial was 0.17±0.45 mm (sirolimus) versus 1.00±0.70 mm (control). If a normal distribution was assumed, late loss accurately estimated in-stent binary angiographic restenosis for the control arm (predicted 35.4% versus observed 35.4%) but underestimated it in the sirolimus arm (predicted 0.6% versus observed 3.2%). Power transformation improved the reliability of the estimate in the sirolimus arm (predicted 3.2% [CI 1.0% to 6.7%]) with similar improvements in the E-SIRIUS trial (predicted 4.0% [CI 1.2% to 7.0%] versus observed 3.9%). In the sirolimus-eluting stent arm, in-stent late loss correlated better with target-lesion revascularization than in-segment late loss (c-statistic=0.915 versus 0.665).

Conclusions—

Because distributions of late loss with a low mean are right-skewed, the use of a transformation improves the accuracy of predicting low binary restenosis rates. Late loss is monotonically correlated with the probability of restenosis and yields a more efficient estimate of the restenosis process in the era of lower binary restenosis rates.
Cyclooxygenases, Thromboxane, and Atherosclerosis
Authors: Egan Karine M. , Wang Miao , Lucitt Margaret B. , Zukas Alicia M. , Puré Ellen , Lawson John A. , FitzGerald Garret A.
Published: January 2005

Background—

Antagonism or deletion of the receptor (the TP) for the cyclooxygenase (COX) product thromboxane (Tx)A
2
, retards atherogenesis in apolipoprotein E knockout (ApoE KO) mice. Although inhibition or deletion of COX-1 retards atherogenesis in ApoE and LDL receptor (LDLR) KOs, the role of COX-2 in atherogenesis remains controversial. Other products of COX-2, such as prostaglandin (PG) I
2
and PGE
2
, may both promote inflammation and restrain the effects of TxA
2
. Thus, combination with a TP antagonist might reveal an antiinflammatory effect of a COX-2 inhibitor in this disease. We addressed this issue and the role of TxA
2
in the promotion and regression of diffuse, established atherosclerosis in Apobec-1/LDLR double KOs (DKOs).

Methods and Results—

TP antagonism with S18886, but not combined inhibition of COX-1 and COX-2 with indomethacin or selective inhibition of COX-2 with Merck Frosst (MF) tricyclic, retards significantly atherogenesis in DKOs. Although indomethacin depressed urinary excretion of major metabolites of both TxA
2
, 2,3-dinor TxB
2
(Tx-M), and PGI
2
, 2,3-dinor 6-keto PGF
1α
(PGI-M), only PGI-M was depressed by the COX-2 inhibitor. None of the treatments modified significantly the increase in lipid peroxidation during atherogenesis, reflected by urinary 8,12-iso-iPF
2α
-VI. Combination with the COX-2 inhibitor failed to augment the impact of TP antagonism alone on lesion area. Rather, analysis of plaque morphology reflected changes consistent with destabilization of the lesion coincident with augmented formation of TxA
2
. Despite a marked effect on disease progression, TP antagonism failed to induce regression of established atherosclerotic disease in this model.

Conclusions—

TP antagonism is more effective than combined inhibition of COX-1 and COX-2 in retarding atherogenesis in Apobec-1/LDLR DKO mice, which perhaps reflects activation of the receptor by multiple ligands during disease initiation and early progression. Despite early intervention, selective inhibition of COX-2, alone or in combination with a TP antagonist, failed to modify disease progression but may undermine plaque stability when combined with the antagonist. TP antagonism failed to induce regression of established atherosclerotic disease. TP ligands, including COX-1 (but not COX-2)–derived TxA
2
, promote initiation and early progression of atherogenesis in Apobec-1/LDLR DKOs but appear unimportant in the maintenance of established disease.
Locating a Blood Pressure Quantitative Trait Locus Within 117 kb on the Rat Genome
Authors: Garrett Michael R. , Meng Haijin , Rapp John P. , Joe Bina
Published: January 2005

Previously, a blood pressure (BP) quantitative trait locus (QTL) on rat chromosome 9 (RNO9) was localized to a <2.4 cM interval using congenic strains generated by introgressing segments of RNO9 from the Dahl salt-resistant (R) rat into the background of the Dahl salt-sensitive (S) rat. Renal gene expression using Affymetrix gene chips was profiled on S and a congenic strain spanning the 2.4-cM BP QTL interval. This analysis identified 20 differentially expressed genes/expressed sequence tags. Of these, the locus with the greatest differential expression (30- to 35-fold) was regulated endocrine-specific protein 18 (
Resp18
), which also mapped in the 2.4-cM BP QTL interval. Additional substitution mapping located the QTL to <0.4 cM or ≈493 kb. This newly defined QTL region still included
Resp18
. Nucleotide variants were identified between S and R genomic DNA of
Resp18
in the coding, 5′ regulatory and 3′ untranslated regions. The coding sequence variation (T/C) occurs in exon 2 and predicts an amino acid change (Ile/Val) in the protein product.
Resp18
was considered a differentially expressed positional candidate for the QTL. To fine-map the BP QTL, we constructed a congenic strain with a smaller introgressed region. Compared with the S rat, this strain (1) had significantly lower BP, (2) did not contain the R form of
Resp18
, and (3) did not retain the rather spectacular differential expression of
Resp18.
Together, these results demonstrate that a BP QTL independent of
Resp18
exists within the newly defined 117-kb QTL region on RNO9.