bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeting population entering phase III trials: A new stratified adaptive phase II design
Authors: Tournoux‐Facon Caroline , Rycke Yann De , Tubert‐Bitter Pascale
Published: January 2011

The primary goal of phase II studies is to assess the efficacy of the new treatment in order to decide whether it has sufficient activity to warrant further evaluation in a phase III comparative trial. However, many adequately conducted phase II trials are negative leading to termination of drug development. Heterogeneity of the population is often considered to be a cause of treatment effect dilution. One approach to determine the sensitive subpopulation is to conduct several phase II trials, one in each specific subset of patients. This option might unethically increase the number of non‐sensitive patients under evaluation. Adaptive two‐stage designs have been recently proposed. London and Chang proposed a global one‐sample test for response rates for stratified phase II clinical trials, whereas Jones and Holmgren proposed an adaptive design that allows preliminary determination of efficacy that may be restricted to a specific subpopulation defined by biomarker status. These two methods do not allow early termination for efficacy in one or several subgroups as they are extensions of the Simon design. The authors propose an alternative method to deal with stratification in phase II clinical trials and identification of the best target population. This method is based on the multiple‐stage Fleming design allowing for early stopping rules for either efficacy or inefficacy. It also integrates a procedure testing whether treatment effects are similar or heterogeneous between the two groups. The operating characteristics of this method were compared with those of a standard Fleming design using exact binomial probabilities. Copyright © 2011 John Wiley & Sons, Ltd.
Detection of spatial disease clusters with LISA functions
Authors: Moraga Paula , Montes Francisco
Published: January 2011

Detection of disease clusters is an important tool in epidemiology that can help to identify risk factors associated with the disease and in understanding its etiology. In this article we propose a method for the detection of spatial clusters where the locations of a set of cases and a set of controls are available. The method is based on local indicators of spatial association functions (LISA functions), particularly on the development of a local version of the product density, which is a second‐order characteristic of spatial point processes. The behavior of the method is evaluated and compared with Kulldorff's spatial scan statistic by means of a simulation study. It is shown that the LISA method yields high sensitivity and specificity when it is used to detect simulated clusters of different sizes and shapes. It also performs better than the spatial scan statistic when they are used to detect clusters of irregular shape; however, it presents relatively high type I error in situations where the number of cases is high. Both methods are applied for detecting spatial clusters of kidney disease in the city of Valencia, Spain, in the year 2008. Copyright © 2011 John Wiley & Sons, Ltd.
A framework for the collaborative specification of semantically annotated business processes
Authors: Francescomarino Chiara Di , Ghidini Chiara , Rospocher Marco , Serafini Luciano , Tonella Paolo
Published: January 2011

Semantic annotations are a way to provide a precise meaning to business process elements, which supports reasoning on properties and constraints. Among the obstacles preventing widespread adoption of semantic annotations are the technical skills required to manage the formalization of the semantics and the difficulty of reconciling the different viewpoints of different analysts working on the same business process. In this paper, we support business analysts in the collaborative annotation of business processes by means of a tool inspired to the Wiki pages model. Using this tool, analysts can concurrently work on process elements, ontology concepts, process annotation or constraint specification. The underlying formalism is not exposed in the Wiki pages, where natural language templates are used. Copyright © 2011 John Wiley & Sons, Ltd.
Portable imaging system for on‐site analysis using CMOS imager—microfluidic analysis and fluorescence imaging
Authors: Misawa Nobuo , Takeuchi Shoji
Published: January 2011

This paper reports on a portable imaging system using a complementary metal oxide semiconductor (CMOS) imager for microfluidic analysis and fluorescence imaging with an organic light emitting diode (OLED). The portable CMOS imager is useful for onsite microfluidic analysis, and the OLED works as a light source for fluorescent observations. The system needs only five elements: a laptop computer, a CMOS imaging device, an optical filter, microfluidic channels, and OLEDs. Using this system, we succeeded in a bead‐based microfluidic assay, capturing the video of the trapping and releasing process. Furthermore, we observed the fluorescent beads and the dye using an OLED as the light source in this system. As a result, we found that (i) submillimeter objects could be in focus with about 1 mm distance from CMOS imaging device surface without a lens; (ii) microfluidic experiments with poly(dimethylsiloxane) channels were possible on the CMOS imager; and (iii) OLED can potentially be used as a light source for this system. We believe that this system is useful for point‐of‐care diagnostic sensing and onsite microfluidic analysis including fluorescence detection. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Recent progress in MEMS electret generator for energy harvesting
Authors: Suzuki Yuji
Published: January 2011

Energy harvesting is a method by which energy naturally present in the environment is captured and then converted into electricity for use in low‐power electronics. Among the various energy sources, structural vibration is believed to be useful for powering wireless sensors in various applications such as sensor network and structural health monitoring. In the present paper, after a brief introduction to electret materials and charging technologies, recent progress in microelectromechanical systems (MEMS) electret generators is reviewed. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A study of making clear body‐conducted speech using differential acceleration
Authors: Nakayama Masashi , Ishimitsu Shunsuke , Nakagawa Seiji
Published: January 2011

An existing problem for speech recognition is that the recognition rate tends to decrease because of the noise. Body‐conducted speech offers a robust signal extraction method to extract speech signals from noisy environments, particularly because body‐conducted speech is a propagated sound and not easily influenced by noise. However, when body‐conducted speech is extracted with an accelerator, the typical frequency component of 2 kHz or more decreases in comparison with normal speech. Therefore, much research has been carried out investigating the techniques for improving the sound quality of body‐conducted speech. Particularly, conventional methods require normal speech to estimate clear speech. Here, we propose a technique that combines differential acceleration and noise reduction to estimate a clear signal using only body‐conducted speech. By comparing spectrogram differences with each method, we found that the Wiener filtering method was suitable for eliminating noise with differential acceleration. Thereafter, improvements in recognition rates were obtained using retrieval signals although the decoder has an acoustic model made by speech parameters. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Development of spatially separated coculture system of the sympathetic neuron and the cardiomyocyte
Authors: Takeuchi Akimasa , Moriguchi Hiroyuki , Kotani Kiyoshi , Miwa Keiko , Lee Jong‐Kook , Noshiro Makoto , Jimbo Yasuhiko
Published: January 2011

Rat superior cervical ganglion (SCG) neurons and the ventricular myocytes (VMs) were cocultured in chambers made of polydimethylsiloxane. The chambers were placed on a microelectrode array (MEA) substrate and connected with a pathway. Twenty‐four hours after dissemination of the VMs, neurites of the SCG neurons outgrew through the pathway and reached the VMs. Spontaneous electrical activities of the SCG neurons and the VMs were observed several days after the dissemination. Constant‐voltage stimulation (1 V, 1 ms, biphasic square pulses) was applied to the SCG neurons at the frequency of 10 Hz using 32 electrodes. Contraction rate of the VMs increased by 153 ± 110% immediately after the stimulation to the SCG neurons was stopped. Then contraction rate gradually decreased and returned to almost the same rate as before the stimulation 5 min after the stimulation. Propranolol (β‐adrenergic receptor antagonist) prevented contraction rate of the VMs from increasing after electrical stimulation to the SCG neurons. These results suggest that neuromuscular junctions were formed between the SCG neurons and the VMs and that this coculture system can be utilized in the research of cell–cell interactions between the sympathetic neurons and the cardiomyocytes. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A revised method to detect erroneous characters wrongly substituted, deleted, and inserted at the end position in Japanese sentences and ‘bunsetsu’s
Authors: Araki Chikahiro , Mori Mikio , Taniguchi Shuji
Published: January 2011

A method to detect the erroneous characters wrongly substituted, deleted, and inserted at the interior location of Japanese sentences and ‘bunsetsu’s using mth‐order Markov chain model has been proposed earlier and was found to be useful in detecting these erroneous characters. However, with this method it is difficult to detect erroneous characters at the end position of Japanese sentences and ‘bunsetsu’s, because the Markov chain probabilities of erroneous characters at the end position of sentences and ‘bunsetsu’s, do not remain smaller than the critical value T the same number of times. This paper proposes a method to detect erroneous characters located at the end position of sentences and ‘bunsetsu’s using the ‘skipped Markov chain model’ in addition to the ‘connected Markov chain model’. From experiments with newspaper articles, the proposed method is shown to be useful to correct erroneous characters located at the end position of sentences and ‘bunsetsu’s. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A vibration control method for power‐assisted moving vibration systems
Authors: Hara Susumu , Yamada Yoji , Ito Koji , Morita Yoshifumi
Published: January 2011

In order to reduce physical burden of workers in industries, power‐assist devices (PADs) have been introduced. In many conventional PADs, the controlled objects are assumed as rigid bodies. This letter presents a vibration control method for power‐assisted moving vibration systems. The power assist is realized by an impedance control. If the impedance characteristics of the power‐assisted system are perfectly realized, they correspond to the disturbance dynamics for the vibration control. In this letter, we adopt the disturbance‐accommodating LQ optimal control method. A cart with a one‐degree‐of‐freedom vibration system is selected as a controlled object example. The effectiveness of the proposed method is verified by simulations. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Intrauterine aortic valvuloplasty in fetuses with critical aortic stenosis: experience and results of 24 procedures
Authors: Arzt W. , Wertaschnigg D. , Veit I. , Klement F. , Gitter R. , Tulzer G.
Published: January 2011

Objective

Valvuloplasty of the fetal aortic valve has the potential to prevent progression of critical aortic stenosis (AS) to hypoplastic left heart syndrome (HLHS). The aim of the study was to assess 24 aortic valvuloplasties regarding indications, success rate, procedure‐related risks and outcome.

Methods

Between January 2001 and December 2009 we performed 24 aortic valvuloplasties in 23 fetuses with critical AS at a median gestational age of 26 + 4 (range, 21 + 3 to 32 + 5) weeks by a transabdominal ultrasound‐guided approach. Four fetuses had hydrops as a late sign of heart failure.

Results

In 16/24 procedures (66.7%) corresponding to 16/23 fetuses (69.6%) the procedures were technically successful, with one intrauterine death in this group. After an initial learning curve, success rate improved to 78.6% (11 of the last 14 interventions were successful). In 10 out of the 15 (66.7%) successfully‐treated and liveborn fetuses a biventricular circulation could be achieved postnatally. All four fetuses with hydrops had successful interventions, hydrops disappearing within 5 weeks. In 8/24 interventions (33.3%) the aortic valve could not be treated successfully, with intrauterine fetal death in two of these cases. In one fetus a repeat procedure was successful. All surviving fetuses with unsuccessful (n = 5) or no (n = 5) procedure performed developed HLHS until delivery.

Conclusions

Fetal aortic valvuloplasty could be performed successfully in selected fetuses with critical AS and evolving HLHS, with a biventricular outcome in two thirds of the patients. Safety and success rate were dependent on patient selection and the level of experience of the whole interventional team. In fetuses with AS and hydrops, aortic valvuloplasty could reverse end‐stage heart failure and hydrops and ensure fetal survival. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Accuracy of sonographic fetal weight estimation: a matter of presentation
Authors: Melamed N. , Ben‐Haroush A. , Meizner I. , Mashiach R. , Yogev Y. , Pardo J.
Published: January 2011

Objectives

To assess the accuracy of sonographic weight estimation for fetuses in breech presentation, and to determine whether certain sonographic models perform better than others in cases of breech presentation.

Methods

This was a retrospective cohort study of all sonographic weight estimations of fetuses in breech presentation performed within 3 days prior to delivery (n = 165). The accuracy of weight estimation was evaluated using eight sonographic models and was compared with a control group of fetuses in vertex presentation matched to the study group by birth weight and fetal gender (n = 165).

Results

After exclusion of a model based on femur diaphysis length alone, which was found to be highly inaccurate, the systematic error for fetuses in breech presentation was smaller than that observed for fetuses in vertex presentation (mean of all models − 0.14% vs. 2.0%, P = 0.01). The random error was higher in cases of breech presentation (9.4–13.2% vs. 7.5–8.9%, P < 0.05), and was lower for models that are based on three to four biometric indices (9.4–9.5%) compared with models that incorporate one to two biometric indices (10.8–13.6%, P < 0.05). Overall, the higher random error outweighed the decrease in the systematic error, as reflected by the lower fraction of weight estimations within 10% of birth weight among fetuses in breech presentation. Models based on three to four biometric indices were more accurate in detecting the weight thresholds beyond which a trial of vaginal delivery is usually not recommended.

Conclusion

Sonographic weight estimation appears to be less accurate for fetuses in breech presentation, principally because of a larger random error. The use of sonographic models that are based on three to four biometric indices, training aimed at improving measurement in breech fetuses and the development of sonographic models derived from fetuses in breech presentation, may improve the accuracy of weight estimation in these cases. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
First‐trimester screening for trisomy 21 in Denmark: implications for detection and birth rates of trisomy 18 and trisomy 13
Authors: Ekelund C. K. , Petersen O. B. , Skibsted L. , Kjaergaard S. , Vogel I. , Tabor A. ,   and the Danish Fetal Medicine Research Group
Published: January 2011

Objectives

In Denmark a new national guideline for prenatal screening and diagnosis was issued in 2004 according to which all pregnant women should be offered a first‐trimester combined risk assessment for trisomy 21 (T21). The aim of this study was to investigate whether the new screening strategy for T21 has changed the gestational age at which trisomy 18 (T18) and trisomy 13 (T13) are diagnosed prenatally, and the number of infants born with T18 or T13.

Methods

We collected from the Danish Cytogenetic Central Register information on all prenatal and postnatal chromosome analyses for T18 or T13, registered from 1997 to 2007. Information on first‐trimester screening results was collected from each department of obstetrics and gynecology performing the nuchal translucency scans. The cut‐off used for referral to invasive diagnostic testing for T21 and for T18/T13 was 1 : 300 and 1 : 150 at screening, respectively.

Results

In total, there were 435 cases with T18 and 168 cases with T13 between 1997 and 2007 in Denmark. The estimated incidence of T18 and T13 at the time of delivery was calculated as 2.5 and 1.6 per 10 000 deliveries, respectively. The number (proportion) of cases diagnosed before week 18 increased significantly, from 63 (59.4%) in 1997 and 1998 to 90 (80.4%) in 2006 and 2007 (P < 0.001). In addition, the number of T18 and T13 cases diagnosed prenatally after week 22 or postnatally decreased significantly, from 34 (32.1%) in 1997 and 1998 to seven (6.3%) in 2006 and 2007 (P < 0.0001). For women participating in first‐trimester risk assessment in 2006 and 2007, the detection rate of T18 and T13 was 78.8% (95% CI, 71.0–86.7%).

Conclusion

The number of T18 and T13 fetuses diagnosed before week 18 increased significantly after the introduction of a combined first‐trimester screening strategy for T21 in Denmark. In addition, the total number of fetuses diagnosed late in pregnancy and infants born with T18 or T13 decreased significantly. The national detection rate for T18 and T13 in the first trimester is comparable with detection rates found in modeled datasets and other prospective studies. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Prediction of fetal macrosomia: effect of sonographic fetal weight‐estimation model and threshold used
Authors: Melamed N. , Yogev Y. , Meizner I. , Mashiach R. , Pardo J. , Ben‐Haroush A.
Published: January 2011

Objective

To compare the accuracy of 21 sonographic fetal weight‐estimation models and abdominal circumference (AC) as a single measure for the prediction of fetal macrosomia (> 4000 g) using either fixed or optimal model‐specific thresholds.

Methods

A total of 4765 sonographic weight estimations performed within 3 days prior to delivery were analyzed. The predictive accuracy of 21 published sonographic fetal weight‐estimation models was calculated using three different thresholds: a fixed threshold of 4000 g; a model‐specific threshold obtained from the inflexion point of the receiver–operating characteristics (ROC) curve; and a model‐specific threshold associated with the highest overall accuracy. Cluster analysis was used to determine whether a certain combination of fetal biometric indices is associated with a higher predictive accuracy than others.

Results

For a fixed threshold of > 4000 g, there was considerable variation among the models in sensitivity (range, 13.6–98.5%) and specificity (range, 63.6–99.8%) for fetal macrosomia. Use of the threshold derived from the inflexion point of the ROC curve decreased the intermodel variation to a minimum (sensitivity, 84.4–91.4%; and specificity, 79.5–86.3%). Even when this optimal model‐specific threshold was applied, models based on three to four biometric indices were more accurate than were models based on only two biometric indices or on AC as a single measure (P = 0.03).

Conclusions

Sonographic fetal weight‐estimation models based on three to four biometric indices appear to be more accurate than are models based on two indices or on AC as a single measure, for the diagnosis of macrosomia. In these cases, the use of an optimal, model‐specific threshold is associated with a higher degree of accuracy than is the uniform use of a fixed threshold of an estimated weight of > 4000 g. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Accuracy of prenatal three‐dimensional ultrasound in the diagnosis of cleft hard palate when cleft lip is present
Authors: Bäumler M. , Faure J.‐M. , Bigorre M. , Bäumler‐Patris C. , Boulot P. , Demattei C. , Captier G.
Published: January 2011

Objective

To investigate the accuracy of prenatal axial three‐dimensional (3D) ultrasound in predicting the absence or presence of cleft palate in the presence of cleft lip.

Methods

Between March 2005 and January 2009, there were 81 cases with a prenatal two‐dimensional (2D) ultrasound screening diagnosis of unilateral or bilateral cleft lip at 22–25 weeks of gestation referred to our tertiary care center. Of these, 79 fetuses were included in this prospective study and two were excluded. Axial 3D ultrasound imaging of the fetal palate was performed and the diagnoses were compared with clinical findings at delivery. The frequencies of intact and cleft palate, the degree of association between the prenatal predictions and postnatal findings and the probability of detection of cleft lip and palate were determined.

Results

Of 79 prenatal predictions, 77 (97%) were correct and the association between the prenatal predictions and postnatal findings was strong. The sensitivity for detection of cleft lip and palate within this high‐risk population was 100% and the specificity was 90%. In one of the excluded cases, the palate could not be visualized due to a fetal prone position. There were chromosomal anomalies in 4% of cases and associated structural or growth anomalies in 23%, termination of pregnancy was carried out in 4% and intrauterine fetal demise occurred in 3%.

Conclusion

Axial 3D ultrasound of the fetal palate has high accuracy in identifying prenatal cleft palate when cleft lip is diagnosed at mid‐trimester 2D ultrasound screening. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Transvaginal sonography vs. clinical examination in the preoperative diagnosis of deep infiltrating endometriosis
Authors: Hudelist G. , Ballard K. , English J. , Wright J. , Banerjee S. , Mastoroudes H. , Thomas A. , Singer C. F. , Keckstein J.
Published: January 2011

Objective

The aim of this study was to compare the diagnostic performance of clinical vaginal examination with that of transvaginal sonography (TVS) in the presurgical diagnosis of deep infiltrating endometriosis.

Methods

One‐hundred and fifty‐five women with symptoms suggestive of endometriosis were included. One‐hundred and twenty‐nine patients met the inclusion criteria and were prospectively and independently assessed by vaginal examination and TVS prior to a diagnostic laparoscopy and, where appropriate, radical resection and histological confirmation of endometriosis was performed. Sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV) and positive and negative likelihood ratios (LR+ and LR−) were calculated for each test method.

Results

In total, 83 (64%) women had histological confirmation of endometriosis, 52 (40%) of whom had deep infiltrating endometriosis. The prevalence of endometriosis on the uterosacral ligaments, pouch of Douglas, vagina, bladder, rectovaginal space and rectosigmoid was 23.3%, 16.3%, 8.5%, 3.1%, 6.9% and 24%. PPV, NPV, LR+ and LR− for vaginal examination were 92%, 87%, 41.56 and 0.60 for ovarian endometriosis; 43%, 84%, 2.48 and 0.63 for uterosacral ligament disease; 64%, 95%, 9.14 and 0.26 for involvement of the pouch of Douglas; 80%, 97%, 42.91 and 0.28 for vaginal endometriosis; 78%, 98%, 46.67 and 0.23 for endometriosis of the rectovaginal space; 100%, 98%, 75.60 and 0.75 for bladder involvement; 86%, 84%, 18.97 and 0.63 for rectosigmoidal endometriosis. Values for TVS were similar with regard to vaginal and rectovaginal space endometriosis, but were clearly superior to vaginal examination in cases of ovarian (87%, 99%, 24.56 and 0.04), uterosacral ligament (91%, 90%, 31.35 and 0.37) and rectosigmoidal (97%, 97%, 88.51 and 0.1) endometriosis.

Conclusions

TVS is a more useful test than is vaginal examination in detecting endometriosis in the ovaries and rectosigmoid. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Interview Prof. Peatman
Authors: Peatman William B.
Published: January 2011

Für Grundlagenforschung an Atomen, Molekülen, Adsorbaten und Festkörpern sowie für angewandte Forschung ist in den letzten Jahrzehnten die Synchrotronstrahlung zu einem wesentlichen Werkzeug geworden. Synchrotronstrahlung ist eine hervorragende Quelle elektromagnetischer Strahlung (Licht) vom Infraroten bis zum Röntgenbereich. Diese Strahlung wird in speziellen Beschleunigern erzeugt. Ein international renommiertes Forschungsinstitut auf diesem Gebiet der Synchrotronstrahlung ist BESSY in Berlin.
Die Entwicklung der Drehschiebervakuumpumpe
Authors: Oswald Dieter
Published: January 2011

Seit ihrer Erfindung durch Karl Wittig vor über 100 Jahren wurde die Drehschieber‐vakuumpumpe entsprechend der an sie gestellten Anforderungen stetig weiterentwickelt. Wurde sie anfanglich nur als “Luftpumpe” in der physikalischen Forschung benutzt, so verlangte

in den folgenden Jahren ihr größer werdender Einsatz als Prozeßvakuumpumpe in der chemischen Industrie verstarkt Modifikationen, weniger des eigentlichen Pumpenprinzips

als vielmehr der Details und der verwendeten Materialien.
Das Hochvakuumsystem des CERN am 450 GeV Super‐Protonen‐Synchrotron und Speicherring (SPS)
Authors: Wahl Hartmut
Published: January 2011

CERN betreibt seit 1976 sein 450 GeV Super‐Protonen‐Synchrotron (SPS). Das Vakuumsystem des SPS hat eine Gesamtlänge von ca. 10 km; 7 km für den Ring und etwa 3 km für die Strahltransferlinien. Es ist ganzmetallisch, jedoch nicht ausheizbar und ursprünglich so ausgelegt, daß ein Druck von 3.10−7 mbar in 24 Stunden erreicht wurde. Der mittlere Enddruck betrug dann nach mehrmonatiger Pumpzeit etwa 10−8 mbar. Um das SPS ab 1981 zusätzlich als Speicherring für Protonen/Antiprotonen betreiben zu können, mußte im Ring ein Druck von 3.10−9 mbar in 10 Tagen nach Pumpbeginn erreicht werden. Da Ausheizen zur Reduzierung der Abgasrate des Systems nicht möglich ist, konnte man diese Forderung nur durch erhöhte Pumpleistung (mehr Ionenzerstäuberpumpen kombiniert mit Sublimationspumpen) in Verbindung mit einem auf das SPS‐Vakuumsystem abgestimmten Pumpzyklus erfüllen. Der mittlere Enddruck ist nun etwa 5.10−10 mbar nach ca. 2 Monaten Pumpzeit.
Vakuum Lexikon: Normen Für Benennungen Und Meßverfahren
Authors: Jitschin Wolfgang
Published: January 2011

In Diskussionen mit Kollegen stellt man immer wieder fest, daß man zwar die gleiche Sprache (Deutsch) spricht, aber mit den gleichen Worten Verschiedenes meint. Was ist zum Beispiel „Vakuum”︁? Oder was ist „gutes”︁ Vakuum und was ist „schlechtes”︁ Vakuum? Was ist die Empfindlichkeit eines Meßgerätes? Es ist in der Praxis zweckmäßig und imgeschäftlichen Bereich notwendig, die Bedeutung der wichtigen Fachbegriffe eindeutig zu beschreiben, oder anders ausgedrückt, die Benennungen zu normen.
Plasmapolymerisation — Ein Verfahren für viele Anwendungen
Authors: Leiber Jörn , Londschien Martin , Telgenbüscher Klaus , Michaeli Walter
Published: January 2011

Die Plasmapolymerisation ist ein relativ junges Vakuumbeschichtungsverfahren, welches sich durch vielfältige Schichteigenschaften auszeichnet. Aufgrund der geringen thermischen Belastung des Substrates eignet sie sich insbesondere zur Beschichtung von Kunststoffen. In diesem Beitrag wird das Verfahren anhand der Mikrowellen‐Plasmapoly‐merisation erläutert. Das Plasma, der Prozeß und der Anlagenaufbau werden beschrieben, bevor eine Übersicht über einige Anwendungen zeigt, wie vielseitig dieses Beschichtungsverfahren ist. Dabei werden Aspekte berücksichtigt, die für den industriellen Einsatz von Bedeutung sind. Hierzu gehören Beschichtungsabmessungen, Prozeßgeschwindigkeit und Wirtschaftlichkeit des Verfahrens.
Vakuumsystem für den Hochenthalpie‐Windkanal
Authors: Steinmüller Jürgen
Published: January 2011

Das Institut für experimentelle Strömungsmechanik der DLR in Göttingen wurde mit der Aufgabe betraut, einen neuen (in Europa einzigartigen) Windkanal für die Untersuchung der Wiedereintrittsaerodynamik mit der Fähigkeit Hochenthalpieströmung für die Simulation der Realgaseffekte herzustellen.

In Europa gibt es derzeit noch keine Möglichkeit, den hochinteressanten Simulationsbereich zu erforschen. Dies soll sich nun unter Zuhilfenahme von Vakuum ändern.
Dünnschichtanlagen zur Herstellung von flachen Bildschirmen
Authors: Gegenwart Rainer
Published: January 2011

Die Herstellung von flachen Bildschirmen erfordert Dünnschichtverfahren, die auch aus der Mikroelektronik bekannt sind. Ein wesentlicher Unterschied liegt jedoch in den Substratgrößen.

Die Abscheidung von Metallen, Isolatoren und Halbleitern erfolgt mit Sputterund CVD Verfahren in großflächigen Durchlaufanlagen. Zur Strukturierung der Substrate mit Trockenätzverfahren werden statische Einzelsubstratanlagen eingesetzt.
Abprodukte und Abgasentsorgung von Fluor‐ und Chlorverbindungen aus plasmachemischen Prozessen
Authors: Tiller H.‐J. , Meyer J. , Berg D. , Bürger H.‐D.
Published: January 2011

Plasmaprozesse, die mit fluor‐ oder chlorhaltigen Prozeßgasen geführt werden und denen entweder in die Ausgangs mischung oder im Prozeßverlauf durch Reaktionen mit entsprechenden Substraten Kohlenstoffe zugefügt werden, können zur Bildung von ungesättigten Fluorkohlenstoffen bzw. im Falle von Chlor zu höhermolekularen aromatischen Chlorkohlenstoffen führen. Beide Produktarten führen durch Akkumulation an den Wänden der Vakuumanlage bzw. im Pumpenöl zu Mengen, die eine erhöhte Sicherheitsaufmerksamkeit verdienen. Neben der Diskussion der Bildungsbedingungen in Plasmen wurden Konzepte für die Entsorgung von Cl2 und von Fluorkohlenstoffen vorgeschlagen. Beiden Verfahren liegen Hochtemperaturprozesse zugrunde. Im Falle des Chlors erweist sich ein Fe‐Reaktor im Vakuumsystem als sehr effizient. Für Fluorkohlenstoff wird ein Konzept einer Hochtemperaturreaktion auf der Druckseite der Vakuumapparatur vorgeschlagen und deren Wirksamkeit mit Hilfe gaschromatografischer Untersuchungen nachgewiesen.

Friedrich‐Schiller‐Universität Jena, Chemische Fakultät, Institut für Physikalische Chemie, Jena
Schwingquarz — Schichtdickenmessung
Authors: Sotier Stefan
Published: January 2011

Die Beschichtung von Quarzkristallen mit Edelmetallen zur feinen Frequenzabstimmung von Quarzoszillatoren wird seit Jahrzehnten praktiziert, während die Idee, Frequenzänderungen zur Bestimmung der Masse einer Beschichtung heranzuziehen, dagegen relativ neu ist.

An Hand der historischen Entwicklung von einfachen Frequenzmeßverfahren bis zum vollautomatischen „Auto‐Z”︁‐Meßgerät wird gezeigt, wie durch eine stetige Verbesserung der zugrundeliegenden physikalischen Modelle höhere Präzision und längere Lebensdauer der Quarze erreicht werden konnten.

Abschließend werden einige praktische Aspekte skizziert.
Kryopumpen mit neuartiger Regenerationstechnologie
Authors: Kiese Gerhard , Voß Gerhard
Published: January 2011

Es wird eine neue, innovative Kryopump‐Technologie vorgestellt, mit der Kryopumpen innerhalb einer Stunde regeneriert werden können. Für den Anlagenbetreiber resultiert daraus im Vergleich mit der konventionellen Kryo‐pump‐Technologie ein deutlicher, geldwerter Vorteil: mehr Produktionszeit.
Raster‐Tunnel‐Mikroskopie zur Untersuchung und Modifizierung von Festkörperoberflächen
Authors: Hietschold Michael
Published: January 2011

Es wird ein kurzer Überblick zu den Möglichkeiten und Perspektiven der Raster‐Tunnel‐Mikroskopie (STM) gegeben. Ultrahochvakuum sichert — obwohl für die STM‐Funktion selbst nicht unbedingt erforderlich — definierte Oberflächen‐ und Tunnelbedingungen. Letztere sind besonders wichtig für das Erzielen atomarer Auflösung sowie für spektroskopische Anwendungen. Mit überzeugenden Beispielen aus der mittlerweile exzessiven Literatur wird die neue Qualität der lokalen Oberflächen‐Strukturanalyse, ‐Spektroskopie und ‐Modifikation demonstriert, die mit dem Einzug der STM sowie verwandter Raster‐Sonden‐Techniken ermöglicht worden ist.
Untersuchungen zu Zusammenhängen zwischen Schichtmorphologie und Herstellungsbedingungen an amorphen Siliziumnitridschichten
Authors: Zösch Antje , Heberlein Thomas , Feyer Manfred , Wuttke Werner
Published: January 2011

Die Morphologie magnetrongesputterter amorpher SiNx‐Schichten wurde mittels Elektronenmikroskopie untersucht. Dabei wurden kolumnare Strukturen nachgewiesen, die sich in Abhängigkeit der Herstellungsparameter entsprechend der bekannten Strukturzonenmodelle ändern.
Animal clocks: a multitude of molecular mechanisms for circadian timekeeping
Authors: Pegoraro Mirko , Tauber Eran
Published: January 2011

Studies in various model organisms reveal that the expression level of a substantial part of the transcriptome and the proteome exhibits regular daily oscillations. These oscillations are translated to physiological and behavioral rhythms allowing organisms to efficiently anticipate and respond to the daily and seasonally changing environment (e.g., temperature and light). A rather small subset of evolutionary conserved genes drives these oscillations and constitutes the core molecular circadian clock. Here, we review the multiple mechanisms that coexist at various molecular and cellular levels and are involved in the metazoan circadian clock, including transcription/translation negative feedback loops, post‐transcriptional and post‐translational modifications, intracellular translocation, and intercellular signaling. WIREs RNA 2011 2 312–320 DOI: 10.1002/wrna.58

This article is categorized under:

RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications

RNA in Disease and Development > RNA in Development
Recognition ofS‐adenosylmethionine by riboswitches
Authors: Batey Robert T.
Published: January 2011

Riboswitches are regulatory elements commonly found in the 5′ leader sequences of bacterial mRNAs that bind cellular metabolites to direct expression at either the transcriptional or translational level. The effectors of these RNAs are chemically diverse, including nucleobases and nucleosides, amino acids, cofactors, and second messenger molecules. Over the last few years, a number of structures have revealed the architectural means by which RNA creates binding pockets of high affinity and specificity for these compounds. For most effectors, there is a single class of associated riboswitches. However, eight individual classes ofS‐adenosylmethionine (SAM) and/orS‐adenosylhomocysteine (SAH) responsive riboswitches that control various aspects of sulfur metabolism have been validated, revealing a diverse set of solutions to the recognition of these ubiquitous metabolites. This review focuses upon the structures of RNAs that bind SAM and SAH and how they discriminate between these compounds.WIREs RNA2011 2 299–311 DOI: 10.1002/wrna.63

This article is categorized under:

RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry

Regulatory RNAs/RNAi/Riboswitches > Riboswitches
C‐ and N‐catabolic utilization of tricarboxylic acid cycle‐related amino acids by Scheffersomyces stipitis and other yeasts
Authors: Freese Stefan , Vogts Tanja , Speer Falk , Schäfer Bernd , Passoth Volkmar , Klinner Ulrich
Published: January 2011

Scheffersomyces stipitis and the closely related yeast Candida shehatae assimilated the L‐amino acids glutamate, aspartate and proline as both carbon and nitrogen sole sources. We also found this rarely investigated ability in ascomycetous species such as Candida glabrata, C. reukaufii, C. utilis, Debaryomyces hansenii, Kluyveromyces lactis, K. marxianus, Candida albicans, L. elongisporus, Meyerozyma guilliermondii, C. maltosa, Pichia capsulata and Yarrowia lipolytica and in basidiomycetous species such as Rhodotorula rubra and Trichosporon beigelii. Glutamate was a very efficient carbon source for Sc. stipitis, which enabled a high biomass yield/mole, although the growth rate was lower when compared to growth on glucose medium. The cells secreted waste ammonium during growth on glutamate alone. In Sc. stipitis cultures grown in glucose medium containing glutamate as the nitrogen source the biomass yield was maximal, and ethanol concentration and specific ethanol formation rate were significantly higher than in glucose medium containing ammonium as the nitrogen source. Mainly C‐assimilation of glutamate but also N‐assimilation in glucose‐containing medium correlated with enhanced activity of the NAD‐dependent glutamate dehydrogenase 2 (GDH2). A Δgdh2 disruptant was unable to utilize glutamate as either a carbon or a nitrogen source; moreover, this disruptant was also unable to utilize aspartate as a carbon source. The mutation was complemented by retransformation of the GDH2 ORF into the Δgdh2 strain. The results show that Gdh2p plays a dual role in Sc. stipitis as both C‐ and N‐catabolic enzyme, which indicates its role as an interface between the carbon and nitrogen metabolism of this yeast. Copyright © 2011 John Wiley & Sons, Ltd.
Ein neues Salz der Monoperoxokohlensäure: K2(O2)CO2·3.5H2O2
Authors: Hinrichs Friederike , Adam Arnold
Published: January 2011

Potassium peroxocarbonate hemihepta peroxohydrate, K2(O2)CO2·3.5H2O2, crystallizes in the monoclinic space group C2/c (No. 15) with Z = 8 and the lattice parameters a = 17.362(3) Å, b = 8.451(1) Å, c = 13.195(2) Å, β = 112.71(1)° und V = 1786.0(5) Å3. The salt of the monoperoxocarbonic acid could be obtained as colorless needles in a concentrated solution of hydrogen peroxide and potassium hydrogen carbonate. The structure consists of two crystallographic different potassium atoms, one peroxocarbonate group and five hydrogen peroxide molecules. The K–O bond lengths are in the range of 2.699–3.291 Å. Along the c‐axis [(K+)(H2O2)2] layers alternate with [(H2O2)(O2CO2)2–] layers. Along [010] the peroxocarbonate group acts as a mono‐ and bidentate ligand towards one potassium atom. The structure is stabilized via hydrogen bonds with donor‐acceptor‐distances from 2.567 to 2.796 Å and hydrogen bond angles from 163.3 to 178.9°. A Raman spectrum has been measured to confirm the structure.
On Ammonium‐tetrakis(dithiocarbamato)‐bismuth(III)‐monohydrate and Tris(dithiocarbamato)‐bismuth(III)
Authors: Teske Christoph L. , Bensch Wolfgang
Published: January 2011

The title compounds were prepared from aqueous alcoholic solutions by reaction of ammoniumdithiocarbamate with bismuth trichloride. NH4Bi(S2CNH2)4·H2O crystallises in the monoclinic space group P21/c (No. 14) with a = 8.4109(17), b = 13.198(3) and c = 16.678(3) Å, β = 97.17(3)°and Bi(S2CNH2)3 crystallises in the triclinic space group P$\bar{1}$ (No. 2) with a = 5.8951(5), b = 8.3026(7), c = 12.5030(10) Å, α = 103.460(10), β = 95.080(10) and γ = 91.330(10) °. The crystal structure of NH4Bi(S2CNH2)4·H2O comprises isolated polyhedrons around bismuth (eightfold coordination) linked by hydrogen bonds originating from ammonium, the co‐crystallised water and the dithiocarbamate. In the crystal structure of Bi(S2CNH2)3 exist dimeric aggregates comprising two distorted square antiprisms around bismuth, which are linked together by a common edge. They form infinite double chains with composition [Bi2(S2CNH2)6]∞, which are bridged by N–H···S hydrogen bonds. Evaluation of differential thermal analysis data shows that Bi2S3 develops in the temperature range between 125 and 150 °C, whereas mainly gaseous NH3 and CS2 are emitted during the decomposition reaction.
Disorders of bile acid synthesis
Authors: Clayton Peter Theodore
Published: January 2011

Inborn errors of bile acid synthesis can produce life‐threatening cholestatic liver disease (which usually presents in infancy) and progressive neurological disease presenting later in childhood or in adult life. Both types of disease can often be treated very effectively with bile acid replacement therapy and it is therefore important to diagnose these disorders as early as possible. The cholestatic disease in infancy is characterised by conjugated hyperbilirubinaemia with raised transaminases but normal γ‐glutamyl transpeptidase and a biopsy showing a giant cell hepatitis. There is usually evidence of fat‐soluble vitamin malabsorption. The neurological presentation often includes signs of upper motor neurone damage (spastic paraparesis). The most useful screening test for many of these disorders is analysis of urinary cholanoids (bile acids and bile alcohols); this is usually now achieved by electrospray ionisation tandem mass spectrometry. The disorders that are discussed in this review are: 3β‐hydroxysteroid‐Δ5‐C27‐steroid dehydrogenase deficiency, Δ4‐3‐oxosteroid 5β‐reductase deficiency, sterol 27‐hydroxylase deficiency (cerberotendinous xanthomatosis, CTX), oxysterol 7α‐hydroxylase deficiency (including one form of hereditary spastic paraparesis) and the amidation defects, bile acid‐CoA: aminoacid N‐acyltransferase (BAAT) deficiency and bile acid‐CoA ligase deficiency. The disorders of peroxisome biogenesis and peroxisomal β‐oxidation that affect bile acid synthesis will be covered in the review by Ferdinandusse et al.
Dystonic tremor caused by mutation of the glucose transporter gene GLUT1
Authors: Roubergue Anne , Apartis Emmanuelle , Mesnage Valérie , Doummar Diane , Trocello Jean‐Marc , Roze Emmanuel , Taieb Guillaume , De Villemeur Thierry Billette , Vuillaumier‐Barrot Sandrine , Vidailhet Marie , Levy Richard
Published: January 2011

Glucose transporter 1 deficiency syndrome (GLUT1‐DS) is due to heterozygous mutation of the glucose transporter type 1 gene (GLUT1/SLC2A1). GLUT1‐DS is characterized by movement disorders, including paroxysmal exercise‐induced dystonia (PED), as well as seizures, mental retardation and hypoglycorrhachia. Tremor was recently shown to be part of the phenotype, but its clinical and electrophysiological features have not yet been described in detail, and GLUT1 tremor reports are rare. We describe two patients, a young woman and her mother, who were referred to us for tremor. We also systematically review published cases of GLUT1‐DS with tremor (14 cases, including ours), focusing on clinical features. In most cases (10/14), the tremor, which involved the limbs and voice, fulfilled clinical criteria for dystonic tremor (DT), occurring in body areas affected by dystonia. Tremor was the only permanent symptom in 2 cases. Recordings, reported here for the first time, showed an irregular 6‐ to 8.5‐Hz tremor compatible with DT in our two patients. These findings show that tremor, and particularly DT, may be a presenting symptom of GLUT1‐DS. Patients who present with dystonic tremor, with or without mental retardation, seizures, movement disorders and/or a family history, should therefore be screened for GLUT1‐DS.
In Vitro Hemagglutination Activity of β‐Conglycinin and Glycinin Fractions and Feeding Study of Non‐Thermal Treated Soy Protein
Authors: Ma Yating , Wang Tong , Faris Richard , Spurlock Michael
Published: January 2011

The purpose of this study was to use non‐thermal means to reduce hemagglutination activities of soy proteins and thereby improve the feeding quality of the resulting treated proteins. Two storage proteins in soybeans, β‐conglycinin‐ and glycinin‐rich fractions, were shown to have in vitro hemagglutination activity. The activity of the β‐conglycinin fraction was not reduced by hydrolysis with single proteases, but the hemagglutination activity was fully eliminated by multiple enzyme treatments if it was first heated. However, the activity of glycinin fraction was not fully eliminated by either single or multiple enzyme hydrolysis. Pepsin and pancreatin hydrolysis, which was effective in eliminating hemagglutination activity of soybean agglutinin (SBA), was used to generate a feed material for in vivo evaluation of nutritional quality of soy white flake (SWF). SBA in reducing agent‐treated then pepsin–pancreatin treated SWF was deactivated on analytical scale experiment, but not in the feed material. The treated SWF feed material did not improve chick growth performance compared with the raw SWF. However, chicks did not show enlargement of the pancreas or the intestines compared to the raw SWF feed, indicating deactivation of anti‐nutritional factors. The trypsin inhibitors seemed to play a more important role than the hemagglutination activity of soy proteins in this nutritional test.
Continued growth of the hip after fixation of slipped capital femoral epiphysis using a single cannulated screw with a proximal threading
Authors: Sailhan Frédéric , Courvoisier Aurélien , Brunet Océane , Chotel Franck , Berard Jérôme
Published: January 2011

Background

The most commonly used method for unstable slipped capital femoral epiphysis (SCFE) remains in situ fixation. Depending on the surgeon's preference, screws or Kirschner wires are used for stabilizing the slipped upper femoral epiphysis. The purpose of this study was to evaluate the ability of a single cannulated screw with a proximal threading to ensure stabilization, growth, and remodeling of the slipped epiphysis.

Methods

A retrospective study was performed identifying 23 children treated for unstable SCFE under 50° by means of a single cannulated screw with proximal threading. All patients attended a radiological evaluation immediately after surgery and at physeal closure. The width of the epiphysis cut by the Klein line, the width and length of the femoral neck, the centrocalcar distance (CCD) angle, and the articulotrochanteric distance (ATD) were evaluated.

Results

All patients had a stabilized epiphysis at the last follow-up, with no case of recurring slip. Radiological comparison of the affected side between the preoperative and the last follow-up evaluation showed a statistically significant improvement in the neck length and width.

Conclusion

Fixation of the epiphysis using proximally threaded screws allows the preservation of femoral neck growth. The cannulated screw with proximal threading seems to be a safe and relevant implant to help to restore a close-to-normal hip at skeletal maturity.
Human aspects of internet services: considering the needs of users and providers
Authors: Pinhanez Claudio S.
Published: January 2011

This paper discusses the need and possible forms of human interfaces to Internet services, challenging the common notion that Internet services are simply computer-computer systems governed by machine protocols with little need of concern for human issues. We first examine the case where Internet services are provided to human users, showing that the user-system interaction becomes a typical service relationship, which can be better understood in the framework of Service Science. Based on the six basic characteristics of services we explore 15 issues which should be taken in account when designing human interfaces for Internet services. We also depart from traditional HCI by arguing that the fundamental goal of the human interface of an Internet service is to create and maintain a relationship with the user. We then look into Internet services being used by computer applications, where we discuss the need of a backdoor human interface for the maintenance and control people working in the Internet service provision system. Both situations have been little explored by the Internet services or the HCI fields of research.