bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Maximum Tracking Rate of Dual‐Chamber Pacemakers Required by Children and Young Adults for a Maximal Cardiorespiratory Performance
Authors: MATHONY U. , SCHMIDT HENDRIK , GRÖGER C. , FRANCIS DARREL P. , KONZAG I. , MÜLLER‐WERDAN URSULA , WERDAN KARL , SYSKA JOACHIM
Published: May 2005

Introduction: Children and young adults require a higher maximum tracking rate (MTR) for physical activity. The objective of the present study was to observe whether higher MTR of 170 or 190 beats per minute (bpm) have a positive impact on the maximal cardiorespiratory capacity of children and young adults in comparison with a lower MTR of 140 bpm.

Methods: Fifteen patients with atrioventricular block and normal sinus‐node chronotropic function (age 7–24 years) with DDD‐ (14) or VDD‐pacemakers (PM) (1) were enrolled. First, the MTR was adjusted to 140 bpm for 6 weeks and elevated in a second step to 170 or 190 bpm. At the end of each period two cardiopulmonary exercise tests, a 24‐hour ECG and a PM test were performed.

Results: All patients increased their maximal heart rate (139.0 ± 1.0 vs 177.0 ± 10.0 bpm, P < 0.001), peak cardiorespiratory capacity (2.4 ± 0.6 vs 2.8 ± 0.7 W/kg, P < 0.001), peak oxygen uptake (28.3 ± 7.0 vs 35.7 ± 9.5 mL/kg/min, P < 0.005), and oxygen uptake (23.7 ± 7.4 vs 29.3 ± 8.4 mL/kg/min, P < 0.02) at the anaerobic threshold. There were no evident heart rhythm disturbances with elevated MTR. Patients with a Wenckebach behavior of the PM had an attenuated increase of maximal cardiorespiratory performance.

Conclusion: Children and young adults with DDD‐/VDD‐PM benefit from an elevated MTR by an increased cardiorespiratory capacity, without having more heart rhythm disturbances. A Wenckebach behavior of the PM should be avoided.
QT Interval Prolongation and Torsades de Pointes Due to a Coadministration of Metronidazole and Amiodarone
Authors: KOUNAS STAVROS P. , LETSAS KONSTANTINOS P. , SIDERIS ANTONIOS , EFRAIMIDIS MICHALIS , KARDARAS FOTIOS
Published: May 2005

This report documents the occurrence of torsades de pointes (TdP) caused by marked QT interval prolongation in the case of a 71‐year‐old woman receiving both metronidazole and amiodarone for the treatment of pseudomembranous colitis and paroxysmal atrial fibrillation. The case highlights a previously unknown drug interaction. The role of inhibition of cytochrome P‐450 CYP3A4 is discussed.
Variable Electrocardiographic Effects of Short‐Term Quinidine Sulfate Administration in Brugada Syndrome
Authors: WATANABE HIROSHI , CHINUSHI MASAOMI , WASHIZUKA TAKASHI , SUGIURA HIROTAKA , HIRONO TAKASHI , KOMURA SATORU , HOSAKA YUKIO , YAMAURA MASAYUKI , TANABE YASUTAKA , FURUSHIMA HIROSHI , FUJITA SATORU , AIZAWA YOSHIFUSA
Published: May 2005

Quinidine, a class I antiarrhythmic agent with blocking property of transient outward current, is a possible candidate for the suppression of ventricular fibrillation in patients with Brugada syndrome; although there is a concern that its ability to these effects may be proarrhythmic. Therefore, we evaluated the effect of quinidine sulfate on ST‐segment elevation in Brugada syndrome. In 8 patients with Brugada syndrome, the magnitude of ST‐elevation at the J‐point (STJ), and the ST‐segment configuration in leads V1–V3, were compared before and on day 2 after the initiation of quinidine administration. In 3 patients, quinidine attenuated STJ by ≥0.1 mV. Of these 3 patients, ST‐segment elevation was normalized in 2 patients, while the ST‐segment configuration was unchanged in another. In another 3 patients, quinidine augmented STJ by ≥0.1 mV without any change of ST‐segment configuration, and the augmentation was returned to baseline after the discontinuation of quinidine. Quinidine exhibited no effect on the ST‐segment in the remaining 2 patients. The favorable effects of quinidine on the ST‐segment tended to be more pronounced in patients with prominent ST‐elevation at baseline. In 1 patient, quinidine was effective in eliminating both ST‐segment elevation and repetitive tachyarrhythmia episodes. In conclusion, the effects of quinidine on ST‐segment elevation were variable. Quinidine may potentially augment the ST‐segment elevation in some patients with Brugada syndrome.
Prevalence of Venous Anatomic Variants and Occlusion Among Patients Undergoing Implantation of Transvenous Leads
Authors: OGINOSAWA YASUSHI , ABE HARUHIKO , NAKASHIMA YASUHIDE
Published: May 2005

Background: The implantation of transvenous leads may be prohibited by venous occlusion or anatomical variants. The prevalence of these conditions among patients undergoing transvenous pacing or implantable cardioverter defibrillator (ICD) leads implantation has not been systematically studied. This study examined the prevalence of venous anatomic variants and/or venous occlusion, and related risk factors, prior to lead implantation.

Method: The study included 273 consecutive patients scheduled for implantation of transvenous pacing or ICD leads. Before the procedure, the venous network of arms, neck, and thorax was evaluated by bilateral intravenous digital subtraction angiography (DSA).

Results: Complete venous occlusion associated with developed collateral circulation was observed in 12 patients (4.4%); at the site of the left innominate vein in 9, left subclavian vein in 2, and right subclavian vein in 1 patient. Of 12 patients with venous occlusion, 7 patients had a history of prior surgical procedure. A persistent left superior vena cava was observed in 1 patient (0.4%). The presence of abnormal findings on DSA was significantly higher on the left than the right side (P < 0.001). The cardio‐thoracic ratio (CTR) was significantly greater in patients with venous occlusions than patients with normal circulation (P = 0.012).

Conclusions: Asymptomatic venous abnormalities are not rare among patients requiring transvenous pacing lead implantation. Careful attention should be paid when implanting pacing or ICD leads from the left side, especially in patients with an increased CTR or history of prior insertion for central venous catheter.
Utility of Echocardiographic Tissue Synchronization Imaging to Redirect Left Ventricular Lead Placement for Improved Cardiac Resynchronization Therapy
Authors: DOHI KAORU , SUFFOLETTO MATTHEW , GANZ LEONARD , ZENATI MARCO , GORCSAN JOHN
Published: May 2005

An 80‐year‐old woman with severe symptomatic heart failure (ejection fraction of 13%), and left bundle branch block (QRS duration of 160 ms) underwent cardiac resynchronization therapy (CRT). She had significant baseline dyssynchrony with a septal to posterior wall delay of 160 ms by echocardiographic tissue synchronization imaging (TSI). Despite exhaustive efforts, a stable posterior‐lateral coronary vein lead position could not be achieved with the standard percutaneous approach, resulting in anterior coronary vein lead placement. This resulted in no improvement in the patient's symptoms or ventricular function. Follow‐up TSI revealed earlier activation of the anteroseptal site and worsened dyssynchrony with septal to posterior wall delay of now 290 ms. This information prompted surgical revision of the left ventricular (LV) lead position via limited thoracotomy and posterior‐lateral epicardial lead implantation. Pacing at the new lead site resulted in a 30% increase in stroke volume and symptomatic improvement. TSI in this case redirected lead position in a clinical nonresponder, resulting in a favorable response to CRT.
Successful Pulmonary Vein Isolation Using Transvenous Catheter Cryoablation Improves Quality‐of‐Life in Patients with Atrial Fibrillation
Authors: TSE HUNG‐FAT , SIN PUI‐YEE , SIU CHUNG‐WAH , TSANG VELLA , LAM CINDY L.K. , LAU CHU‐PAK
Published: May 2005

Background: Recent studies have demonstrated that transvenous catheter cryoablation is a safe and effective technique for creating pulmonary veins (PVs) electrical isolation for the treatment of atrial fibrillation (AF). However, the impacts of this procedure on quality‐of‐life (QoL) have not been evaluated.

Methods and Results: We studied the effects of PV isolation using transvenous catheter cryoablation on QoL in 46 patients (34 men, mean age: 50 ± 12 years) with drug‐refractory AF. QoL was assessed by Medical Outcomes Study Short Form‐36 (SF‐36) and Symptom Checklist at baseline and 3‐month after cryoablation, and compared with those in a sex‐age matched normal control. At 3‐month follow‐up, 24 of 46 patients (52%) had no recurrence of AF, including 11 patients who were not taking antiarrhythmic drugs. At baseline, patients with AF had significantly lower QoL scores in overall and in 5/8 subscales of SF‐36 than the sex‐age matched control group (P < 0.05). In patients with successful outcome after cryoablation showed a significant improvement in overall and in 5/8 subscales of SF‐36 QoL scores have significantly increased as compared with the baseline (P < 0.05). Furthermore, their QoL scores in overall and in 6/8 subscales of SF‐36 were similar to the sex‐age matched control group (P > 0.05). The Symptom Checklist also showed significant reduction in both the symptoms frequency scores and symptoms severity scores at 3‐month follow‐up as compared with baseline (P < 0.05).

Conclusions: Successful PV isolation using transvenous catheter cryoablation is associated with significant reduction in the frequency and severity of AF symptoms and improvement in the general QoL, reaching the levels of normal controls.
Right Ventricular Outflow Tract Endocardial Pacing Complicated by Intercostal Muscle Twitching
Authors: OGINOSAWA YASUSHI , ABE HARUHIKO , TAKEMASA HIROKO , KOHNO RITSUKO
Published: May 2005

A recipient of a dual‐chamber pacing system, with a bipolar endocardial lead screwed into the right ventricular outflow tract (RVOT), developed intercostal muscle twitching. No lead perforation was identified. This observation suggests that meticulous attention should be paid to this potential complication when choosing the RVOT as a site of permanent endocardial pacing.
Institutionalizing Neutrally Competent Policy Analysis: Resources for Promoting Objectivity and Balance in Consolidating Democracies
Authors: Weimer David L.
Published: May 2005

Creating institutions that foster the production of objective and balanced policy analysis is a challenging task for all types of regimes. The value of neutral competence often suffers in tradeoffs with the value of responsiveness, especially in the exercise of executive authority. Institutional designers, however, are not without resources for structuring arrangements to promote the production of objective and balanced policy analysis: organizations can be created with an incentive to achieve “reputations” for neutral competence; organizations can be isolated from being too politically responsive through forms of “independence”; for promoting interaction based on “professional norms” can be created to resolve conflicts about prediction; “participation in international organizations” can be leveraged to counteract domestic biases; and “transparency” can be employed to facilitate balancing of views or to shame severe abuses. This essay sets out the logic underlying design with these sorts of institutional resources, illustrates their use primarily in the U.S. context, and speculates on their application in consolidating democracies.
Keeping Policy Churn Off the Agenda: Urban Education and Civic Capacity
Authors: Marschall Melissa , Shah Paru
Published: May 2005

Building on the conceptual framework developed by the Civic Capacity and Urban Education Project, we investigate why sustained reform is so difficult in urban school systems. Our study addresses two questions: How does the concept of civic capacity relate to the policy change process and how do its various components relate to each other? And to what extent does civic capacity foster agenda consensus in the context of urban education reform? To address these questions we focus on the connection between problems and solutions and deal directly with the question of how mayoral leadership impacts this process. Using the Project's survey of key stakeholders and independent indicators of agenda setting and stakeholder support/opposition culled from media coverage in 11 large U.S. cities, we find considerable variation in levels of civic capacity, particularly low levels of stakeholder agreement on reform solutions, but also convincing evidence that strong mayoral leadership may indeed play an important role in fostering greater agenda consensus.
Mating frequency in dispersing potato tuber moth, Phthorimaea operculella, and its influence on the design of refugia to manage resistance in Bt transgenic crops
Authors: Cameron P.J. , Wallace A.R. , Madhusudhan V.V. , Wigley P.J. , Qureshi M.S. , Walker G.P.
Published: May 2005

Mating of potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), was investigated in relation to the dispersal of males in laboratory and field trials. The effect of stimulating the flight of males to light sources in a large cage on their mating ability was estimated for three age groups, and compared with similar estimates for confined moths. Although the mating of males declined with ages of up to 15 days, simulated dispersal had no effect on subsequent mating when the males were paired with virgin females. The dispersal of male moths was also categorised by the initial flight activity of untethered moths to a light source. Scores for poor, moderate, and good flight provided a repeatable measure of initial male flight activity, but the degree of activity was not related to their subsequent mating ability. In the field, virgin female potato tuber moths were tethered at various distances from the edge of isolated potato crops and then dissected to determine their mating status. Female mating frequency averaged 75% at the crop margin, remained above 50% up to 200 m, and then declined to 19% at 360 m from the margin. Derivation of the mating probability for an individual male potato tuber moth confirmed earlier work by other researchers that has indicated a tendency for dispersal prior to mating, and that males retain their ability to mate as they disperse from a crop. The influence of dispersal and mating on gene flow between crops, and its potential effects on refuge size required to minimise the development of resistance to Bt transgenic potato crops was examined.
Effects of elevated CO2 and transgenic Bt cotton on plant chemistry, performance, and feeding of an insect herbivore, the cotton bollworm
Authors: Chen Fajun , Wu Gang , Ge Feng , Parajulee Megha N. , Shrestha Ram B.
Published: May 2005

Effects of elevated atmospheric CO2 (double‐ambient CO2) on the growth and metabolism of cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), fed on transgenic Bacillus thuringiensis (Berliner) (Bt) cotton [Cry1A(c)], grown in open‐top chambers, were studied. Two levels of CO2 (ambient and double‐ambient) and two cotton cultivars (non‐transgenic Simian‐3 and transgenic GK‐12) were deployed in a completely randomized design with four treatment combinations, and the cotton bollworm was reared on each treatment simultaneously. Plants of both cotton cultivars had lower nitrogen and higher total non‐structural carbohydrates (TNC), TNC:Nitrogen ratio, condensed tannin, and gossypol under elevated CO2. Elevated CO2 further resulted in a significant decrease in Bt toxin level in GK‐12. The changes in chemical components in the host plants due to increased CO2 significantly affected the growth parameters of H. armigera. Both transgenic Bt cotton and elevated CO2 resulted in a reduced body mass, lower fecundity, decreased relative growth rate (RGR), and decreased mean relative growth rate in the bollworms. Larval life‐span was significantly longer for H. armigera fed transgenic Bt cotton. Significantly reduced larval, pupal, and adult moth weights were observed in the bollworms fed elevated CO2‐grown transgenic Bt cotton compared with those of bollworms reared on non‐transgenic cotton, regardless of the CO2 level. The efficiency of conversion of ingested food and of digested food of the bollworm were significantly reduced when fed transgenic Bt cotton, but there was no significant CO2 or CO2× cotton cultivar interaction. Approximate digestibility of larvae reared on transgenic cotton grown in elevated CO2 was higher compared to that of larvae fed non‐transgenic cotton grown at ambient CO2. The damage inflicted by cotton bollworm on cotton, regardless of the presence or absence of insecticidal genes, is predicted to be more serious under elevated CO2 conditions because of individual compensatory feeding on host plants caused by nitrogen deficiency.
Oviposition vs. offspring fitness in Aphidius colemani parasitizing different aphid species
Authors: Ode Paul J. , Hopper Keith R. , Coll Moshe
Published: May 2005

We measured the acceptance and suitability of four aphid species [Aphis gossypii Glover, Myzus persicae (Sulzer), Rhopalosiphum padi (L.), and Schizaphis graminum (Rondani)] (Homoptera: Aphididae) for the parasitoid Aphidius colemani Viereck (Hymenoptera: Braconidae). Female parasitoids parasitized fewer R. padi than the other three aphid species, and fewer offspring successfully completed development in R. padi than in the other three host species. Sex ratios of emerging adults were more male‐biased from R. padi than from the other three aphid species, suggesting that R. padi is a poor quality host for this population of A. colemani. Ovipositing A. colemani encountered R. padi at a slower rate, spent more time handling R. padi, and parasitoid offspring died at a higher rate in R. padi compared to A. gossypii. Our results show that oviposition behavior and offspring performance are correlated. In each experiment, we tested the effect of the host species in which the parasitoids developed (parental host) on the number of hosts attacked, the proportion of each host species accepted for oviposition and the survival of progeny. Parental host affected maternal body size and, through its effect on body size, the rate of encounter with hosts. Other than this, parental host species did not affect parasitism.
EMPIRICAL AND ETHICAL PROBLEMS WITH CUSTODY RECOMMENDATIONS:
Authors: Tippins Timothy M. , Wittmann Jeffrey P.
Published: May 2005

This article proposes a four‐level model of clinical inferences to analyze the psychological evaluation process in custody matters. At each level the authors summarize the status of the relevant psychological literature and conclude that, as clinicians respond to the ultimate issues (e.g., who should be the custodial parent) the empirical foundation for such conclusions is tenuous or non‐existent. A jurisprudence argument is also made that such opinions should be routinely excluded from the fact‐finding process. Given the significant potential for specific custody recommendations to limit personal liberties and the trajectory of a child's life, the paucity of relevant research available in this area, and profound evidentiary issues, such recommendations should be viewed as ethically inappropriate. A model for what clinicians can ethically say to courts is proposed.
MAKING A PLACE AT THE TABLE:
Authors: Kisthardt Mary Kay , Fines Barbara Glesner
Published: May 2005

This response to Timothy Tippins and Jeffrey Wittmann's article “Empirical and Ethical Problems with Custody Recommendations: A Call for Clinical Humility and Judicial Vigilance” builds upon the authors’ conclusions that custody evaluations cannot and should not be a substitute for the socio‐legal judgment of the best interests of the child. Recognizing that clinical humility and judicial vigilance may not be sufficient to restrain the misuse of psychological evaluation, we offer for consideration three structural changes that would provide for a more appropriate use of the skills and talents custody evaluators bring to legal decisions. We suggest using custody evaluators in the less adversarial setting of preparing parenting plans, revising the procedures by which custody evaluations are elicited in litigation, and adopting the approximation standard for child custody determinations.
TO RECOMMEND OR NOT TO RECOMMEND: THAT IS NOT THE QUESTION
Authors: Martin Lorraine
Published: May 2005

Tippins and Wittmann provide a cogent argument for custody evaluators not to make recommendations to the court. From their forensic and scientific perspectives, they have identified some important issues, which will certainly stimulate interesting discussion among custody evaluators. In response to their article, it is my view that public sector custody evaluations offer a philosophical and procedural alternative to forensic evaluations. This article proposes that recommendations should be viewed as part of the process of evaluations rather than the outcome. Based on a qualitative and interpretive model, recommendations are judged based on their applicability, transferability, and transparency. Recommendations viewed in qualitative terms provide parents with opportunities to step out of litigation and provide guidance for parents’ ongoing roles postseparation.
A SECOND CALL FOR CLINICAL HUMILITY AND JUDICIAL VIGILANCE:
Authors: Gould Jonathan W. , Martindale David A.
Published: May 2005

Offering commentary on “Empirical and Ethical Problems with Custody Recommendations: A Call for Clinical Humility and Judicial Vigilance,” we express our agreement with Tippins and Wittmann. We opine that professional activity stimulates inquiry and it is through inquiry that our knowledge base will be expanded and our skills will be improved. In the interim, we should be mindful of our limitations, and actively articulate the ways in which the incompleteness of our knowledge base and the deficiencies of our assessment tools limit the confidence that can be placed in the recommendations that we offer.
A SHORT COMMENTARY ON TIMOTHY M. TIPPINS AND JEFFREY P. WITTMANN'S “EMPIRICAL AND ETHICAL PROBLEMS WITH CUSTODY RECOMMENDATIONS
Authors: Dessau Hon. Linda
Published: May 2005

In this commentary, the call for clinical humility and judicial vigilance in custody recommendations is confirmed as valid and the Australian experience, where the child custody report writer has for some years been permitted to express an opinion on the ultimate issue, is considered. The inherent risks are briefly discussed, and the question of who of the judge and the social scientist might be better placed to decide the exquisitely difficult children's issues after family breakdown is touched upon. It suggests that a combination of the expert's opinion and judicial fact finding probably produces a result that is as good as it gets. But a greater danger is highlighted. It is the impact of the adversary system, and whether it is suitable in any event to these sensitive court decisions.
ALLEGATIONS AND SUBSTANTIATIONS OF ABUSE IN CUSTODY‐DISPUTING FAMILIES1
Authors: Johnston Janet R. , Lee Soyoung , Olesen Nancy W. , Walters Marjorie G.
Published: May 2005

In this study of 120 divorced families referred for child custody evaluations and custody counseling, multiple allegations of child abuse, neglect, and family violence were raised in the majority of cases. About half of the alleged abuse was substantiated in some way with one fourth involving abuse perpetrated by both parents. Different kinds of allegations were raised against mothers compared with fathers. Implications of these findings for social policy, family court interventions, and the provision of coordinated services within the community are discussed.
EMPLOYING MEDIATION TO APPROACH TRUANTS
Authors: Lindstadt Michael A.
Published: May 2005

Truants have been dealt with by state and school officials with heedlessness, suspension, expulsion, and placement under the power of the courts. One problem faced in decreasing truancy is its lack of a common definition. Statistics show high rates of truancy with kids who subsequently drop out of school and there is a strong correlation between drop‐out and unemployment, welfare, low salary, and imprisonment. The juvenile justice system does not reach the root of the truant's individual problems or adequately attempt to solve or assist the child and family in its goal to develop constructive and autonomous individuals.

Mediation is an alternative to a punishment‐oriented approach to truancy. Mediation is a process in which a neutral third party helps participants reach their own agreement for resolving a dispute. Mediation is adaptable to the many different causes of truancy and can provide multiple benefits to truants and their families. The Ohio Commission On Dispute Resolution & Conflict Management has the most accomplished and consistently progressing truancy mediation program in the nation.

Critics of mediation have scrutinized the process for not placing enough emphasis on mediation's major elements, such as premediation instruction, exploitation of the informality of the process, and a lack of funding, which may render mediation weak and inefficient. Maintaining and emphasizing particular elements will benefit jurisdictions in their utilization of the process.
Test Response and Nonlinear Analysis of a Turbocharger Supported on Floating Ring Bearings
Authors: Holt Chris , San Andre´s Luis , Sahay Sunil , Tang Peter , La Rue Gerry , Gjika Kostandin
Published: May 2005

Measurements of casing acceleration on an automotive turbocharger running to a top speed of 115 krpm and driven by ambient temperature pressurized air are reported. Waterfall acceleration spectra versus rotor speed show the effects of increasing lubricant inlet pressure and temperature on turbocharger rotordynamic response. A comprehensive analysis of the test data shows regimes of speed operation with two subsynchronous whirl motions (rotordynamic instabilities). Increasing the lubricant feed pressure delays the onset speed of instability for the most severe subsynchronous motion. However, increasing the lubricant feed pressure also produces larger synchronous displacements. The effect of lubricant feed temperature is minimal on the onset and end speeds of rotordynamic instability. Nevertheless, operation with a cold lubricant exhibits lower amplitudes of motion, synchronous and subsynchronous. The experimental results show the subsynchronous frequencies of motion do not lock (whip) at system natural frequencies but continuously track the rotor speed. No instabilities (subsynchronous whirl) remain for operating speeds above 90 krpm. Linear and nonlinear analysis results for the operation of a small automotive turbocharger supported on floating ring bearings are presented. A comprehensive fluid film bearing model predicting the forced response of floating ring bearings is also described. The linear rotordynamic model predicts well the rotor free–free modes and onset speed of instability using linearized bearing force coefficients. The nonlinear model incorporating instantaneous bearing reaction forces in the numerical integration of the rotor equations of motion predicts the limit cycle amplitudes with two fundamental subsynchronous whirl frequencies. Comparisons of both models to experimental results follow. The predictions evidence two unstable whirl ratios at approximately 12 ring speed and 12 ring speed plus 12 journal speed. The transient nonlinear responses reveal the importance of rotor imbalance in suppressing the subsynchronous instabilities at large rotor speeds as also observed in the experiments.
Removal of particles during plasma processes using a collector based on the properties of particles suspended in the plasma
Authors: Setyawan Heru , Shimada Manabu , Hayashi Yutaka , Okuyama Kikuo
Published: May 2005

A particle removal system based on the properties of charged particles suspended in a plasma for use in controlling particle contamination during the preparation of silicon dioxide thin films in a plasma-enhanced chemical vapor deposition reactor is described. Since the particles suspended in the plasma carry a negative charge, the application of a positive bias to a metal tube inserted into the plasma would attract negatively charged particles. The system effectively removes particles from the trap regions during operation of the plasma. Even particles as small as about 10nm in size can be removed using this method. Films prepared using the installed particle removal system were found to be nearly free from particle contamination. This is different from the case when the particle removal system is not installed, where some particles are deposited on the film. Even though the particle removal system reduces the rate of film growth by about 40%, it is offset by theresulting clean film, which is free from particle contamination.
Amorphous transparent conductive oxide films of In2O3-ZnO with additional Al2O3 impurities
Authors: Tominaga K. , Fukumoto H. , Kondou K. , Hayashi Y. , Murai K. , Moriga T. , Nakabayashi I.
Published: May 2005

Al-doped In2O3-ZnO films were developed and the influence of Al doping in electrical and optical properties of In2O3-ZnO films was investigated. Amorphous and homologous phases appeared with increasing δ=Zn∕(Zn+In) ratios. The carrier generation mechanism is discussed for these films. Native oxygen defects are the primary donors for the In2O3-ZnO films. Then the low resistivities of 2–4×10−4Ωcm were attained within a narrow range of δ=Zn∕(Zn+In) in the amorphous phase film. Two wt % (percent by weight) Al2O3-doping decreased the resistivity to 1.5–2.1×10−4Ωcm. At doping of 3 and 4 wt % Al2O3, film resistivities of 2–4×10−4Ωcm were attained for a relatively wide range of δ in the amorphous phase due to an increase in carrier concentration at δ=0.3–0.6. However, Al2O3 doping in homologous phase In2O3-ZnO films decreased carrier concentration independently of the levels of Al2O3 doping. Al2O3 doped in the homologous ZnkIn2Ok+3 crystalline films did not act as a donor impurity. The optical band-gap energy for the films deposited above 2 wt% Al2O3 for amorphous film was proportional to Al2O3 content. This is ascribed to lattice distortion caused by Al2O3.
Enhancement of mechanical properties of organosilicon thin films deposited from diethylsilane
Authors: Ross April D. , Gleason Karen K.
Published: May 2005

A strong demand exists for improved low-k intermetal dielectric materials, such as organosilicons, to enhance the performance of ultralarge scale integrated circuits. Pulsed-plasma enhanced chemical vapor deposition was used to deposit organosilicon thin films from diethylsilane and oxygen. Fourier-transform infrared (FTIR) analysis showed significant organic content as well as hydroxyl and silanol moieties in the as-deposited materials. FTIR showed a complete removal of hydroxyl groups after annealing at 400°C for 1h. This removal indicates a condensation reaction between proximal hydroxyl groups leading to the formation of additional Si–O–Si linkages, which would increase both the hardness and modulus of the film. Mechanical property measurements were in accordance with this hypothesis, as both the hardness and modulus increased by over 50% after annealing. Film structure and properties were strongly dependent on the precursor feed ratio.
Electron impact effects on the oxidation of Si(111) at 90 K
Authors: Ohno Shin-ya , Yates John T.
Published: May 2005

The Si(111)-7×7 surface has been subjected to oxidation by molecular O2 at 90 K and the kinetics of this process have been studied by x-ray photoelectron spectroscopy (XPS). In the midst of the oxidation process, the thin oxide layer was electronically excited in ultrahigh vacuum using 100 eV electron bombardment. No charging of the oxide layer was observed. It was found that excitation of the oxide layer by electron bombardment led to almost no change in the oxidation kinetics, measured following bombardment. XPS studies showed that two oxygen-containing surface species are produced by oxidation (in the absence of electrons) with O(1s) binding energies of 533.1 and 535.1 eV. Upon electron bombardment, the higher binding energy species is converted to the lower binding energy species. Continued oxidation after electron bombardment showed that the higher binding energy species was replenished again. This result suggests that adsorption at 90 K leads to highly strained Si–O–Si species and that electron bombardment of these species produces the stable oxidized structure. The results are compared to similar experiments on Al2O3 where, in contrast to a SiO2 film, it was found that surface charging of a thin Al2O3 film on Al(111) leads to a greatly enhanced oxidation rate.
Plasma enhanced atomic layer deposition of HfO2 and ZrO2 high-k thin films
Authors: Lao Sandy X. , Martin Ryan M. , Chang Jane P.
Published: May 2005

A plasma enhanced atomic layer deposition (PEALD) process was developed to deposit high-k dielectric constant materials using alternative metal t-butoxide and oxygen plasma exposures. The deposited thickness increased linearly with an increasing number of precursor/oxygen plasma cycles, and the growth rates of HfO2 and ZrO2 were determined to be 1.1 and 2.8Å∕cycle, respectively. The as-deposited films were determined to be fully oxidized and amorphous by the x-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR). The PEALD films were found to have high concentrations of bridging oxygen bonds with metals (M–O–M) as the film thickness increased, in contrast to the high concentrations of M–O–H in the films deposited by plasma enhanced chemical vapor deposition (PECVD). The M–O–M bonds in the PEALD films were further increased upon annealing at 250 °C in atmosphere with a corresponding decrease in M–O–H concentrations, suggesting the elimination of hydroxyl groups upon annealing. The PEALD HfO2 and ZrO2 films showed higher dielectric constants (25, 22) than those of PECVD deposited films (21, 19), likely due to the enhanced ionic contribution from the M–O–M bonds in the PEALD films. The smallest equivalent oxide thickness (EOT) of 13 Å was achieved by PEALD HfO2 with a leakage current density of 0.2A∕cm2, several orders of magnitude below that of thermally grown SiO2 films with the same EOT.
Temperature dependence of resistivity of Si–Ta film deposited by magnetron sputtering
Authors: Berlicki T. M. , Prociów E. L. , Brzeziński J. , Osadnik S. J.
Published: May 2005

Analysis of conductivity of silicon films doped with tantalum, based on percolation theory, has been carried out. The dependence of resistivity on Ta content in the film and temperature has been presented. The films were deposited by magnetron sputtering on glass substrates. The films with the thickness of ∼0.3μm contained from 2% to 20% of Ta. Based on percolation theory, the effect of Ta content on resistivity and its dependence on temperature were determined.
Anti-emission characteristics of the grid coated with hafnium film
Authors: Jiang Jun , Jiang Bingyao , Ren Congxin , Feng Tao , Wang Xi , Liu Xianghuai , Zou Shichang
Published: May 2005

Hf was deposited onto the surface of Mo grids by ion-beam-assisted deposition. The electron-emission characteristics of the grids with and without Hf, which were contaminated by active electron-emission substances (Ba, BaO) of the cathode, were measured using an analogous-diode method. The surfaces of the grids were analyzed by x-ray diffraction and x-ray photoelectron spectroscopy. The results showed that electron-emission current from the Mo grid coated with Hf film was less than that from the Mo grid without Hf. During the course of the testing, active electron-emission substances from the cathode were deposited continuously onto the surface of the grid. Due to BaHfO3 compounds and Ba-Hf diffusion, the Mo grid coated with Hf effectively reduced the electron-emission substances on the grid from the cathode, which reduced grid electron emission.
Etching of oxynitride thin films using inductively coupled plasma
Authors: Kim Byungwhan , Lee Dukwoo , Kim Nam Jung , Lee Byung Teak
Published: May 2005

In this study, silicon oxynitride (SiON) has been etched in a C2F6 inductively coupled plasma. The process parameters examined include a radio frequency source power, bias power, pressure, and C2F6 flow rate. For process optimization, a statistical experimental design was employed to investigate parameter effects under various plasma conditions. The etch rate increased almost linearly with increasing the source or bias power. Main effect analysis revealed that the etch rate is dominated by the source power. The C2F6 flow rate exerted the least impact on both etch rate and profile angle. It was estimated that the C2F6 effect is transparent only as the etchant is supplied sufficiently. Depending on the pressure levels, the etch rate varied in a complicated way. Parameter effects on the profile angle were very small and the profile angle varied between 83° and 87° for all etching experiments. In nearly all experiments, microtrenching was observed. The etch rate and profile angle, optimized at 1000W source power, 30W bias power, 6mTorr pressure, and 60sccm C2F6 flow rate, are 434nm∕min and 86°, respectively.
Surface and corrosion characteristics of carbon plasma implanted and deposited nickel-titanium alloy
Authors: Poon R. W. Y. , Liu X. Y. , Chung C. Y. , Chu P. K. , Yeung K. W. K. , Lu W. W. , Cheung K. M. C.
Published: May 2005

Nickel-titanium shape memory alloys (NiTi) are potentially useful in orthopedic implants on account of their super-elastic and shape memory properties. However, the materials are prone to surface corrosion and the most common problem is out-diffusion of harmful Ni ions from the substrate into body tissues and fluids. In order to improve the corrosion resistance and related surface properties, we used the technique of plasma immersion ion implantation and deposition to deposit an amorphous hydrogenated carbon coating onto NiTi and implant carbon into NiTi. Both the deposited amorphous carbon film and carbon plasma implanted samples exhibit much improved corrosion resistances and surface mechanical properties and possible mechanisms are suggested.
Kind of oxide-composed superhard nanomultilayer prepared by magnetron sputtering
Authors: Lun Wei , Nan Shao , Fanghua Mei , Geyang Li , Jianguo Li
Published: May 2005

Ti N ∕ Si O 2 nanomultilayers with various modulation layer thicknesses were prepared by multi-target magnetron sputtering method. The composition, growth structures, and mechanical properties of the nanomultilayers were studied by energy dispersive x-ray spectrometry, x-ray diffraction, scanning electron microscope, high-resolution transmission electron microscope, and nanoindenter. The results reveal that although SiO2 and TiN monolithic films formed amorphous and nanocrystalline structures, respectively, the TiN∕SiO2 nanomultilayers crystallized entirely and grew coherently at smaller SiO2 layer thickness (<∼1nm), and columnar crystals with (111) preferred orientation were formed. Correspondingly, the multilayers show superhardness and high elastic modulus with maximum values of 44.5 and 473GPa, respectively. With the further increase of layer thickness, SiO2 layers formed an amorphous structure and blocked the coherent growth of the multilayers, and then the hardness and elastic modulus decreased gradually. On the other hand, the increase of TiN layer thickness caused the hardness and elastic modulus of the multilayers to decrease slightly. However, a high hardness of 38GPa can still be obtained even when TiN layer thickness increases to 8.8nm.
Thermoelectric characterization of sputter-deposited Bi∕Te bilayer thin films
Authors: Liao C. N. , Kuo S. W.
Published: May 2005

Bi ∕ Te bilayer thin films were deposited in sequence on oxidized Si wafers by sputtering and converted into Bi2Te3 alloys by thermal annealing. It was found that the Seebeck coefficient rose from −38μV∕Kto−202μV∕K, the resistivity increased slightly from 2.0×10−3to2.3×10−3Ωcm, and the thermal conductivity decreased from 2.56to0.71W∕mK after the Bi∕Te bilayer samples were annealed at 200°C for 24h. Bi2Te3 is the only compound phase identified in the annealed Bi∕Te bilayer samples by x-ray diffraction analysis. The effects of deposition parameters and postannealing condition on the microstructure and the thermoelectric properties of the Bi∕Te bilayer thin films were investigated.
Summary: Update to ASTM guide E 1523 to charge control and charge referencing techniques in x-ray photoelectron spectroscopy
Authors: Baer D. R.
Published: May 2005

An updated version of the American Society for Testing and Materials (ASTM) guide E 1523 to the methods to charge control and charge referencing techniques in x-ray photoelectron spectroscopy has been released by ASTM [Annual Book of ASTM Standards Surface Analysis (American Society for Testing and Materials, West Conshohocken, PA, 2004), Vol. 03.06]. The guide is meant to acquaint x-ray photoelectron spectroscopy (XPS) users with the various charge control and charge referencing techniques that are and have been used in the acquisition and interpretation of XPS data from surfaces of insulating specimens. The current guide has been expanded to include new references as well as recommendations for reporting information on charge control and charge referencing. The previous version of the document had been published in 1997 [D. R. Baer and K. D. Bomben, J. Vac. Sci. Technol. A 16, 754 (1998)].
Low temperature rf sputtering deposition of (Ba, Sr) TiO3 thin film with crystallization enhancement by rf power supplied to the substrate
Authors: Yoshimaru Masaki , Takehiro Shinobu , Abe Kazuhide , Onoda Hiroshi
Published: May 2005

The (Ba, Sr) TiO3 thin film deposited by radio frequency (rf) sputtering requires a high deposition temperature near 500°C to realize a high relative dielectric constant over of 300. For example, the film deposited at 330°C contains an amorphous phase and shows a low relative dielectric constant of less than 100. We found that rf power supplied not only to the (Ba, Sr) TiO3 sputtering target, but also to the substrate during the initial step of film deposition, enhanced the crystallization of the (Ba, Sr) TiO3 film drastically and realized a high dielectric constant of the film even at low deposition temperatures near 300°C. The 50-nm-thick film with only a 10nm initial layer deposited with the substrate rf biasing is crystallized completely and shows a high relative dielectric constant of 380 at the deposition temperature of 330°C. The (Ba, Sr) TiO3 film deposited at higher temperatures (upwards of 400°C) shows ⟨110⟩ preferred orientation, while the film deposited at 330°C with the 10nm initial layer shows a ⟨111⟩ preferred orientation on a ⟨001⟩-oriented ruthenium electrode. The unit cell of (Ba, Sr) TiO3 (111) plane is similar to that of ruthenium (001) plane. We conclude that the rf power supplied to the substrate causes ion bombardments on the (Ba, Sr) TiO3 film surface, which assists the quasiepitaxial growth of (Ba, Sr) TiO3 film on the ruthenium electrode at low temperatures of less than 400°C.
Construction of a ColD
cda
Promoter-Based SOS-Green Fluorescent Protein Whole-Cell Biosensor with Higher Sensitivity toward Genotoxic Compounds than Constructs Based on
recA
,
umuDC
, or
sulA
Promoters
Authors: Norman Anders , Hestbjerg Hansen Lars , Sørensen Søren J.
Published: May 2005

Four different green fluorescent protein (GFP)-based whole-cell biosensors were created based on the DNA damage inducible SOS response of
Escherichia coli
in order to evaluate the sensitivity of individual SOS promoters toward genotoxic substances. Treatment with the known carcinogen
N
-methyl-
N′
-nitro-
N
-nitrosoguanidine (MNNG) revealed that the promoter for the ColD plasmid-borne
cda
gene had responses 12, 5, and 3 times greater than the
recA
,
sulA
, and
umuDC
promoters, respectively, and also considerably higher sensitivity. Furthermore, we showed that when the SOS-GFP construct was introduced into an
E. coli
host deficient in the
tolC
gene, the minimal detection limits toward mitomycin C, MNNG, nalidixic acid, and formaldehyde were lowered to 9.1 nM, 0.16 μM, 1.1 μM, and 141 μM, respectively, which were two to six times lower than those in the wild-type strain. This study thus presents a new SOS-GFP whole-cell biosensor which is not only able to detect minute levels of genotoxins but, due to its use of the green fluorescent protein, also a reporter system which should be applicable in high-throughput screening assays as well as a wide variety of in situ detection studies.
Use of Stochastic Models To Assess the Effect of Environmental Factors on Microbial Growth
Authors: Ponciano José Miguel , Vandecasteele Frederik P. J. , Hess Thomas F. , Forney Larry J. , Crawford Ronald L. , Joyce Paul
Published: May 2005

We present a novel application of a stochastic ecological model to the study and analysis of microbial growth dynamics as influenced by environmental conditions in an extensive experimental data set. The model proved to be useful in bridging the gap between theoretical ideas in ecology and an applied problem in microbiology. The data consisted of recorded growth curves ofEscherichia coligrown in triplicate in a base medium with all 32 possible combinations of five supplements: glucose, NH4Cl, HCl, EDTA, and NaCl. The potential complexity of 25experimental treatments and their effects was reduced to 22as just the metal chelator EDTA, the presumed osmotic pressure imposed by NaCl, and the interaction between these two factors were enough to explain the variability seen in the data. The statistical analysis showed that the positive and negative effects of the five chemical supplements and their combinations were directly translated into an increase or decrease in time required to attain stationary phase and the population size at which the stationary phase started. The stochastic ecological model proved to be useful, as it effectively explained and summarized the uncertainty seen in the recorded growth curves. Our findings have broad implications for both basic and applied research and illustrate how stochastic mathematical modeling coupled with rigorous statistical methods can be of great assistance in understanding basic processes in microbial ecology.
Adaptation ofCorynebacterium glutamicumto Ammonium Limitation: a Global Analysis Using Transcriptome and Proteome Techniques
Authors: Silberbach Maike , Schäfer Mathias , Hüser Andrea T. , Kalinowski Jörn , Pühler Alfred , Krämer Reinhard , Burkovski Andreas
Published: May 2005

Theresponse ofCorynebacterium glutamicumto ammonium limitation was studied by transcriptional and proteome profiling of cells grown in a chemostat. Our results show that ammonium-limited growth ofC. glutamicumresults in a rearrangement of the cellular transport capacity, changes in metabolic pathways for nitrogen assimilation, amino acid biosynthesis, and carbon metabolism, as well as a decreased cell division. Since transcription at different growth rates was studied, it was possible to distinguish specific responses to ammonium limitation and more general, growth rate-dependent alterations in gene expression. The latter include a number of genes encoding ribosomal proteins and genes for FoF1-ATP synthase subunits.