bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical assessment of the automated AutoDock as a new docking tool for virtual screening
Authors: Park Hwangseo , Lee Jinuk , Lee Sangyoub
Published: September 2006

A major problem in virtual screening concerns the accuracy of the binding free energy between a target protein and a putative ligand. Here we report an example supporting the outperformance of the AutoDock scoring function in virtual screening in comparison to the other popular docking programs. The original AutoDock program is in itself inefficient to be used in virtual screening because the grids of interaction energy have to be calculated for each putative ligand in chemical database. However, the automation of the AutoDock program with the potential grids defined in common for all putative ligands leads to more than twofold increase in the speed of virtual database screening. The utility of the automated AutoDock in virtual screening is further demonstrated by identifying the actual inhibitors of various target enzymes in chemical databases with accuracy higher than the other docking tools including DOCK and FlexX. These results exemplify the usefulness of the automated AutoDock as a new promising tool in structure‐based virtual screening. Proteins 2006. © 2006 Wiley‐Liss, Inc.
A tunable‐fairness cross‐layer scheduler for DVB‐S2
Authors: Vieira F. , Vázquez Castro M. A. , Seco Granados G.
Published: September 2006

Adaptability of the physical layer has become mandatory for unicast services by the second generation of the DVB‐S standard, DVB‐S2. This introduces new challenges as well as degrees of freedom in the design of the packet schedulers operating on the forward link. A main challenge lies in providing quality‐of‐service (QoS) suitable for multimedia applications meeting at the same time the required service level agreements (SLA). In this paper, we present a cross‐layer approach for the design of the forward link packet scheduler that introduces fairness as a tunable parameter. This approach makes it possible to dynamically adapt the scheduler behaviour in order to guarantee fairness depending on the channel conditions. The proposed algorithm also supports differentiation of services that comply with the requirements for implementing QoS. An example scenario is proposed and system performance is computed as a function of the tunable fairness index. Our results show that tunable fairness is an effective scheduling tool for broadband satellite systems implementing adaptive physical layer. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of rate compatible block turbo codes for multimedia application in satellite communication network
Authors: Kim Sooyoung , Ryoo Sunheui , Seob Ahn Do
Published: September 2006

In this paper, we evaluate the performance of the hybrid automatic repeat request (ARQ) scheme combined with adaptive coding in satellite communication systems. A cross‐layer design which combines the ARQ scheme in the data link layer and adaptive coding and modulation in the physical layer is very important to maximize system throughput and/or performance. Due to the long round trip delay in satellite systems, the strategy to adopt may need to be different from that is used in the terrestrial systems. A rate compatible code is a desirable scheme for adaptive coding and hybrid ARQ. In this paper, we propose an adaptive coding scheme with hybrid ARQ using rate compatible block turbo codes, and demonstrate its performance on a mobile satellite channel for multimedia applications. The proposed rate compatible block turbo codes are a very effective tool to improve the performance of satellite systems using adaptive coding with hybrid ARQ. The simulation results presented in this paper reveal that the hybrid ARQ scheme combined with adaptive coding can improve the system performance by effectively compensating for the various channel attenuations. Copyright © 2006 John Wiley & Sons, Ltd.
Networking with multi‐service GEO satellites: cross‐layer approaches for bandwidth allocation
Authors: Celandroni Nedo , Davoli Franco , Ferro Erina , Gotta Alberto
Published: September 2006

Cross‐layer Radio Resource Management (CL‐RRM) has been recently investigated by quite a few research groups in wireless communications. In the specific satellite‐networking environment, the paper presents an overview of different CL‐RRM techniques devoted to dynamic bandwidth allocation, whose interactions span the physical, data link, network and transport layers, in various combinations. A multi‐service setting is considered, in the presence of variations in both traffic and channel conditions. Regarding the latter, bit and coding rate adaptation are adopted as fade countermeasure, and their effect on the higher layers is modelled as a bandwidth reduction. Traffic models and methodologies for dynamic bandwidth allocation and performance optimization are discussed. Numerical examples are presented to highlight throughput/fairness trade‐offs for long‐lived TCP connections that share multiple channels with different fading depth. Copyright © 2006 John Wiley & Sons, Ltd.
Cross‐layer protocol optimization for satellite communications networks: a survey
Authors: Giambene Giovanni , Kota Sastri
Published: September 2006

Satellite links are expected to be one important component of the next‐generation Internet. New satellite system architectures are being envisaged to be fully IP based and support digital video broadcasting and return channel protocols (e.g. DVB‐S, DVB‐S2 and DVB‐RCS). To make the upcoming satellite network systems fully realizable, meeting new services and application requirements, a complete system optimization is needed spanning the different layers of the OSI, and TCP/IP protocol stack. This paper deals with the cross‐layer approach to be adopted in novel satellite systems and architectures. Different cross‐layer techniques will be discussed, addressing the interactions among application, transport, MAC and physical layers. The impacts of these techniques will be investigated and numerical examples dealing with the joint optimization of different transport control schemes and lower layers will be considered referring to a geostationary‐based architecture. Our aim is to prove that the interaction of different layers can permit to improve the higher‐layer goodput as well as user satisfaction. Copyright © 2006 John Wiley & Sons, Ltd.
Oesophagitis dissecans superficialis complicating repeated rigid oesophagoscopy and dilatation
Authors: Ramaswami G , Jain P K , Talati V R
Published: September 2006

Oesophagitis dissecans superficialis is an extremely rare and benign condition where the mucosal epithelium of the oesophagus sloughs off along the whole length of the oesophagus and is expelled as an oesophageal cast. This condition has been reported in association with various aetiological factors. We report a case of an oesophageal cast in a patient who underwent repeated oesophagoscopy and dilatation for a postcricoid web. We discuss the possible relationship between trauma to the upper oesophagus and the development of oesophagitis dissecans superficialis.
Study on breakdown characteristics of a low-pressure dielectric barrier discharge
Authors: LING YI-MING
Published: September 2006

The breakdown characteristics of a low-frequency dielectric barrier discharge (DBD) at low pressure are investigated experimentally in He, Ne and Ar. The current waveform of this DBD, a series of pulses, is caused by the results of the electron avalanches under the action of the applied field and the quenching effect of the wall-charge field on the avalanches. Taking into consideration the diffusion loss of the charged particles in the breakdown processes, the experimental investigation and the theoretical analysis of its breakdown characteristics indicate that its breakdown voltage is higher than the calculation by the Paschen law and depends on the filled-gas pressure and the distance between the electrodes, instead of their product. The ion-induced secondary electron emission coefficient and the mean electron energy at the moment of breakdown can also be determined approximately by measuring the breakdown characteristics of the discharge tubes with different distances between the electrodes and combining the theoretical deductions. The experimental results and the theoretical analysis of the breakdown characteristics of this DBD are discussed.
The Study of Finger Flutings
Authors: Sharpe Kevin , Van Gelder Leslie
Published: September 2006

Archaeologists have usually glossed over parietal finger flutings, especially non-figurative and non-symbolic lines. This article develops a nomenclature and defines four forms to provide a descriptive structure from which to build analyses. It then develops methods for such investigations, using experiments and studies of physiology to derive information about the fluters from the flutings. The methods are applied to each of the four forms of fluting, showing which approaches may be most useful for each form. Broader questions and applications are touched on, including approaches to meaning, figures, and other families of parietal markings such as hand stencils. This approach to flutings augments other approaches to prehistoric ‘art’ by seeking to know about the artists themselves, their gender, age, size, handedness, and the number of individuals involved in creating a panel.
Fragmentation, Personhood and the Social Construction of Technology in Middle and Late Bronze Age Britain
Authors: Brück Joanna
Published: September 2006

This article examines a range of practices involving the deliberate fragmentation of human bodies and objects in Middle and Late Bronze Age Britain. Focusing on evidence from settlements and mortuary sites, it is suggested that metaphorical links were drawn between people and things, and that productive processes such as potting and metallurgy provided potent metaphors for the construction of the human self. Building on these points, it is argued that current models which posit the rise of an ideology of the ‘individual’ during the Bronze Age may be inappropriate in this cultural context.
The management of hypoplastic left heart syndrome with a
right aortic arch
Authors: Tatum Gregory H. , Morell Victor O. , Park Sang C.
Published: September 2006

The combination of hypoplastic left heart syndrome and a right-sided aortic arch is extremely rare and lethal. To the best of our knowledge, no patient with this combination has previously been reported as surviving initial palliation. The anatomic variant is associated with abnormalities in the arteries branching from the aortic arch, making it difficult to construct a reliable source of flow of blood to the lungs. We present here a patient with this combination who survived an initial Damus-Kay-Stansel procedure combined with placement of a conduit from the right ventricle to the pulmonary arteries, and who has subsequently undergone a successful bidirectional cavopulmonary anastomosis. We believe that the conduit placed from the right ventricle provides the most reliable source of flow of blood to the lungs at the time of initial palliation in this usual combination of cardiac lesions.
Experience with intraoperative ultrasound in paediatric cardiac surgery
Authors: Balmer Christian , Barron David , Wright John G.C. , de Giovanni Joe V. , Miller Paul , Dhillon Rami , Brawn William J. , Stümper Oliver
Published: September 2006

Objective: Intraoperative ultrasound was introduced to evaluate the adequacy of repair after surgical repair of congenital cardiac malformations. Our purpose was to review the evolution of this technique at our centre.Methods: We evaluated all intraoperative ultrasound studies undertaken between 1997 and 2002, reviewing the data from 1997 through 2001 retrospectively, but undertaking a prospective audit of studies undertaken from 2002 onwards. In all, we carried out a total number of 639 intraoperative ultrasound studies, from a possible 2737 cardiac operations (23.3%), using the epicardal approach in 580 (90.7%), and transoesophageal ultrasound in the other 59 patients (9.3%). Median age was 0.6 years, with an interquartile range from 0.06 to 3.6 years.Results: The findings obtained using intraoperative ultrasound influenced the surgical management in 63 of the 639 patients (9.9%), suggesting the need for additional surgery in 26, adjustment of the band placed round the pulmonary trunk in 16, preoperative assessment of the cardiac malformation in 5, and confirming the need for prolonged support with cardiopulmonary bypass for impaired ventricular function in 16. There were 18 early reoperations, 5 of which may have been predicted by intraoperative ultrasound. Of the 183 studies reviewed prospectively in 2002, it was not possible to obtain the complete range of views in 8 (4.4%), while in 27 patients (14.7%), the postoperative findings using transthoracic interrogation differed from the findings obtained immediately following bypass.Conclusion: Intraoperative ultrasound is an important technique for monitoring the results of complex congenital cardiac surgery. The immediate recognition of significant lesions, together with multidisciplinary discussion, allows for improved management and prevention of early surgical reintervention.
Criterions for selection of patients for, and results of, a new technique for construction of the modified Blalock-Taussig shunt
Authors: Chowdhury Ujjwal K. , Venugopal Panangipalli , Kothari Shyam S. , Saxena Anita , Talwar Sachin , Subramaniam Ganapathy , Singh Rajvir , Pradeep Kizakke K. , Sathia Siddhartha , Kumar A. Sampath
Published: September 2006

Background: We describe alternative surgical techniques for construction of systemic-to-pulmonary arterial shunts, and propose criterions for their application in selected patients.Patients and methods: We constructed a variety of modified systemic-to-pulmonary arterial shunts, using polytetrafluroethylene grafts, in 92 selected patients with cyanotic congenital heart disease and anomalies of the aortic arch and systemic veins. Their age ranged from 7 days to 3.6 years, with a mean of 7.08 months. We performed 88 operations through a thoracotomy. Of this cohort, 60 patients underwent a second-stage operation, with 15 receiving a superior cavopulmonary connection, 16 a total cavopulmonary connection, and 29 proceeding to biventricular repair after a mean interval of 15.6 months. We have 21 patients awaiting their second or final stage of palliation.Results: There were five early (5.4%) and six late deaths (6.8%), two of which were related to construction of the shunts. At a mean follow-up of 45.29 months, the increase in diameter of pulmonary trunk and its right and left branches was uniform and significant (p value less than 0.001). Pulmonary arterial distortion requiring correction at the time of second-stage operation was observed in 5 patients (6.1%). Adequate overall palliation was achieved in 98% of the cohort at 8 months, 91% at 12 months, and 58% at 18 months.Conclusions: Patients with a right- or left-sided aortic arch and right-sided descending thoracic aorta, those with anomalies of systemic venous drainage masking the origin of great arterial branches, and those withdisproportionately small subclavian arteries, constitute the ideal candidates for our suggested modification of the construction of a modified Blalock-Taussig shunt. The palliation provided by these shunts was satisfactory, with predictable growth of pulmonary arteries, insignificant distortion in the great majority, and easy take-down.
Who benefits from intervention in, as opposed to screening of, overweight and obese children?
Authors: Graf Christine , Koch Benjamin , Bjarnason-Wehrens Birna , Sreeram Narayanswami , Brockmeier Konrad , Tokarski Walter , Dordel Sigrid , Predel Hans-Georg
Published: September 2006

Aims: StEP TWO is a school- and family-based intervention consisting of extra lessons, healthy nutrition and physical education for overweight and obese children in primary schools, aimed at reducing body mass index by maintenance or reduction of weight, and improving motor abilities. We analysed differences in changes in anthropometric, cardiovascular and obesity parameters between children who underwent intervention, non-participants in intervention, and controls.Methods: Anthropometric data and waist circumference were recorded for 1678 children; body mass index and body mass index–standard deviation score were calculated. Blood pressure was measured after 5 minutes at rest. 121 overweight and obese children enrolled at 3 schools involved in programmes of intervention were invited to take part; 40 of them completed the programme from November 2003 to July 2004. Of these overweight children, 74 were invited, but did not take part. As controls, we enrolled 155 overweight and obese children from 4 other schools.Results: After the programme, the children involved in intervention showed a lower increase in the body mass index (0.3 plus or minus 1.3 versus 0.7 plus or minus 1.2 kilograms per metre squared) and an approximately three times higher diminution of the body mass index–standard deviation score in comparison with their controls (−0.15 plus or minus 0.26 versus 0.05 plus or minus 0.27). Systolic blood pressure was significantly lowered by 9.5 plus or minus 19.6 millimetres of mercury in those involved in intervention, but increased in the control group by 0.5 plus or minus 16.5 millimetres of mercury. Among those invited but not participating, the increase of the body mass index (0.5 plus or minus 1.3 kilograms per metre squared) was less, and the reduction of the body mass index-standard deviation score (−0.09 plus or minus 0.31) and systolic blood pressure (−5.3 plus or minus 15.6 millimetres of mercury) was higher than in the control group. Overweight but not obese children seem to benefit from a screening examination alone.Conclusions: Early preventive measures in schools are necessary and effective for overweight and obese primary school children. The screening itself seems also to have a minor positive effect, especially for overweight children. Sustainability of the observed improvements over a longer period remains to be confirmed.
Clinical and epidemiological description of aortic dissection in Turner's syndrome
Authors: Højbjerg Gravholt Claus , Landin-Wilhelmsen Kerstin , Stochholm Kirstine , Eilersen Hjerrild Britta , Ledet Thomas , Born Djurhuus Christian , Sylvén Lisskulla , Baandrup Ulrik , Østergaard Kristensen Bent , Sandahl Christiansen Jens
Published: September 2006

Background: Women with Turner's syndrome have an increased risk of congenital cardiac malformations, ischaemic heart disease, hypertension and stroke. Aortic dissection seems to occur with increased frequency. Aim: To describe in more detail aortic dissection as encountered in Turner's syndrome, giving attention to clinical, histological and epidemiological aspects. Materials and methods: Based on a retrospective study, we describe the clinical, karyotypic, and epidemiological aspects of aortic dissection as encountered in cases of Turner's syndrome seen in Denmark and Sweden. Results: The median age at onset of aortic dissection in 18 women was 35 years, ranging from 18 to 61 years. Fourteen of 18 women had a 45,X karyotype, while 2 patients had 45,X/45,XY, and 2 had the 45,X/46,X+r(X) complement, respectively. Echocardiography was performed in 10 of 18 patients before their acute illness, and showed signs of congenital cardiac disease, with either bifoliate aortic valves, dilation of the aortic root, or previous aortic coarctation evident in most patients. In 5 patients evidence of a bifoliate aortic valve was conclusive. Hypertension was present in 5 of 18 patients, while 10 of the patients died from aortic dissection, of so-called type A in 6, type B in 3, while in the final case the origin of dissection could not be determined. Biochemical analysis showed altered ratio between type I and type III collagen. Histology showed cystic medial necrosis in 3 of 7 cases. We estimated an incidence of dissection of 36 per 100,000 Turner's syndrome years, compared with an incidence of 6 per 100,000 in the general population, and a cumulated rate of incidence of 14, 73, 78, and 50 per 100,000 among 0–19, 20–29, 30–39, and 40+ year olds, respectively. Conclusion: Aortic dissection is extremely common in the setting of Turner's syndrome, and occurs early in life. Patients with Turner's syndrome should be offered a protocol for clinical follow-up similar to that provided for patients with Marfan syndrome, and each clinic should embrace a programme for follow-up.
Correlations with operative anatomy of real time three-dimensional echocardiographic imaging of congenital aortic valvar stenosis
Authors: Sadagopan Shankar N. , Veldtman Gruschen R. , Sivaprakasam Muthukumaran C. , Keeton Barry R. , Gnanapragasam James P. , Salmon Anthony P. , Haw Marcus P. , Vettukattil Joseph J.
Published: September 2006

Objective: To define the anatomic characteristics of the congenitally malformed and severely stenotic aortic valve using trans-thoracic real time three-dimensional echocardiography, and to compare and contrast this with the valvar morphology as seen at surgery. Design: Prospective cross-sectional observational study Setting: Tertiary centre for paediatric cardiology Methods: All patients requiring aortic valvotomy between December 2003 and July 2004 were evaluated prior to surgery with three-dimensional echocardiography. Full volume loop images were acquired using the Phillips Sonos 7500 system. A single observer analysed the images using “Q lab 4.1” software. The details were then compared with operative findings. Results: We identified 8 consecutive patients, with a median age of 16 weeks, ranging from 1 day to 11 years, with median weight of 7.22 kilograms, ranging from 2.78 to 22 kilograms. The measured diameter of the valvar orifice, and the number of leaflets identified, corresponded closely with surgical assessment. The sites of fusion of the leaflets were correctly identified by the echocardiographic imaging in all cases. Fusion between the right and non-coronary leaflets was identified in half the patients. Dysplasia was observed in 3 patients, with 1 patient having nodules and 2 shown to have excrescences. At surgery, nodules were excised, and excrescences were trimmed. The dysplastic changes correlated well with operative findings, though statistically not significant. Conclusion: We recommend trans-thoracic real time three-dimensional echocardiography for the assessment of the congenitally malformed aortic valve, particularly to identify sites of fusion between leaflets and to measure the orificial diameter. The definition of nodularity, and the prognosis of nodules based on the mode of intervention, will need a comparative study of patients submitted to balloon dilation as well as those undergoing surgical valvotomy
Successful release of recurrent pulmonary venous obstruction after repair of totally anomalous pulmonary venous connection by transcatheter implantation of stents
Authors: Waki Kenji , Arakaki Yoshio , Baba Kiyoshi
Published: September 2006

We report a 3-month-old female infant, in whom pulmonary venous obstruction occurred after repair of totally anomalous pulmonary venous connection, and which was successfully released by a transcatheter implantation of a stent using the transseptal approach. Close follow-up is required, since the long-term outcome is still unclear. Nevertheless, transcatheter implantation of stents is a promising option for treating this challenging lesion.
Terminal arrhythmia in a patient with Mustard's operation
Authors: Chakrabarti Shanta , Graham Stuart Alan
Published: September 2006

In spite of significant improvements in outcome, adults surviving the Mustard procedure continue to be at risk of premature death, cardiac failure, and arrhythmias. Primary ventricular fibrillation as a cause of sudden death in these patients may not be uncommon, and implantation of a defibrillator should be considered, particularly if there is systemic ventricular dysfunction and pre-existing heart block.
ErbB receptors and their ligands in the breast
Authors: Zahnow Cynthia A.
Published: September 2006

ErbB receptor tyrosine kinases are membrane-bound receptors that possess intrinsic, ligand-activated, tyrosine kinase activity. Binding of growth factors to these receptors induces the formation of ErbB homo- and heterodimers and initiates a signalling cascade that traverses the cytoplasm to communicate with the nucleus and the cytoskeleton. The effect of this cascade is the regulation of cellular proliferation, differentiation, apoptosis, migration and adhesion. Although ErbB signalling is important for normal growth and development in the breast, a dysregulation of ErbB activity can lead to tumourigenesis. This review will focus on the role of ErbB signalling in both normal mammary gland development and breast cancer, with an emphasis on the mechanisms behind receptor activation and the therapeutic agents designed to inhibit ErbB activity.
Therapie der chronischen Hepatitis C
Authors: Moradpour  , Blum
Published: September 2006

Die Infektion mit dem Hepatitis-C-Virus (HCV) ist weltweit eine der häufigsten Ursachen der chronischen Hepatitis, Leberzirrhose und des hepatozellulären Karzinoms. In diesem Beitrag werden der aktuelle Stand und neue Entwicklungen auf dem Gebiet der Therapie der chronischen Hepatitis C kurz zusammengefasst. Die Standardtherapie mit pegyliertem Interferon-α und Ribavirin führt bei bis zu 40–50% der Genotyp-1- und ca. 80% der Genotyp-2- und -3-infizierten Patienten zur anhaltenden Viruselimination. Eine besondere Bedeutung kommt der Erkennung und Beeinflussung von Kofaktoren der Krankheitsprogression zu (Alkohol- und Nikotinkarenz bzw. -reduktion, Impfung gegen Hepatitis A und B, Reduktion von Übergewicht). Aufbauend auf einem verbesserten Verständnis der molekularen Virologie und Pathogenese der Hepatitis C werden heute vielversprechende neue präventive und therapeutische Strategien exploriert.
Therapie von Problemfällen mit chronischer Hepatitis C
Authors: Zeuzem
Published: September 2006

Die Standardtherapie der chronischen Hepatitis C ist die Kombination eines pegylierten Interferons mit Ribavirin. Primäres Therapieziel einer antiviralen Therapie bei Patienten mit Hepatitis C ist der fehlende Nachweis Hepatitis-C-spezifischer RNA im Serum sechs Monate nach Therapieende mittels eines sensitiven molekularen Nachweisverfahrens. Unter den so genannten «Problemfällen» werden Patienten mit schwieriger Indikationsstellung (asymptomatisch, minimale histologische Veränderungen, persistierend normale Transaminasen, etc.), Patienten mit geringen therapeutischen Erfolgschancen (z.B. HCV-Genotyp-1-Infektion mit hoher Ausgangsviruslast, Vorliegen einer Leberzirrhose, Immunsuppression, HIV-Koinfektion, etc.), Patienten, die bei der Ersttherapie nicht erfolgreich behandelt wurden, Patienten, die Interferon-α und/oder Ribavirin nicht vertragen und Patienten mit unzureichender Compliance zusammengefasst. Bei schwieriger Indikationsstellung sollte die Vorstellung in einer Schwerpunktpraxis oder einem Zentrum erfolgen. Optionen für Patienten mit geringen Erfolgschancen und bei Nonrespondern umfassen die Re-Therapie mit pegyliertem Interferon und Ribavirin in höherer Dosis und/oder über längere Therapiezeiträume. Für diese Patienten sowie für solche, die nicht mit Interferon und/oder Ribavirin behandelt werden können, stehen zahlreiche neue Medikamente im Rahmen klinischer Prüfungen zur Verfügung. Bei allen Therapien mit pegyliertem Interferon und Ribavirin steht zudem die Optimierung der Compliance und die aktive Behandlung von Nebenwirkungen (z.B. Serotonin-Reuptake-Inhibitoren bei Depression, Erythropoetin bei Ribavirin-assoziierter Anämie, etc.) im Mittelpunkt.
Lebertransplantation
Authors: Steurer
Published: September 2006

Die orthotope Lebertransplantation (LTX) ist heute eine Standardtherapie mit guten Ergebnissen. Neue Techniken wie Split- oder Lebendspende erhöhten die Zahl an Lebertransplantationen nicht entscheidend, sind jedoch vor allem für Kinder eine optimale Alternative. Insgesamt bietet die LTX eine gute therapeutische Möglichkeit für Patienten im Endstadium einer Lebererkrankung sowie für Personen mit akutem Leberversagen. Leider stellt der zunehmende Organmangel ein grosses Problem dar und der Tod auf der Warteliste wird für mehr und mehr Patienten bittere Realität.
Palpable Purpura und nephrotisches Syndrom – Ätiologie?
Authors: Cuculi  , Brink  , Hadjeres  , Arnold  , Glatz  , Fischer
Published: September 2006

Ein 46-jähriger Diabetiker stellt sich mit palpabler Purpura an den unteren Extremitäten und mit einer nephrotischen Proteinurie vor. Die Biopsie aus dem Unterschenkel ergibt eine leukozytoklastische Vaskulitis. In der Nierenbiopsie stellt man eine Purpura-Schönlein-Henoch-Nephritis (PSHN) fest. Da einzelne Berichte und Fallserien von einer Assoziation von HSPN mit Tumoren berichten, wird zwecks Tumorsuche eine Computertomographie des Abdomens und des Thoraxes durchgeführt. Man stellt einen Sigmapolypen fest, der später endoskopisch entfernt wird und sich als Carcinoma in situ entpuppt. Es stellt sich die Frage, ob Erwachsene, die sich mit PSHN vorstellen, einer Tumorsuche unterzogen werden sollten.
A simulation study on the semiannual variation of the ionospheric F2 layer zonal electric fields at the magnetic equator
Authors: Yu Tao , Wan Weixing , Liu Libo , Li Xiaoyin , Luan XiaoLi , Tang Wei
Published: September 2006

With a theoretical model which yields ionospheric electric fields, we study the yearly variation of ionospheric electric fields at middle and low latitudes under the condition of low solar and quiet geomagnetic activities. The results show the following characteristics. When the ionospheric electric fields are calculated individually in the Northern (or Southern) Hemisphere without including the influence of the other hemisphere (uncoupled), the electric field in the Northern (or Southern) Hemisphere varies in an obvious annual pattern; when the electric field is calculated simultaneously in both hemispheres including the influence of the other hemispheres (coupled), the electric field varies in a predominantly semiannual pattern. Moreover, quite good consistency was found between the behaviors of semiannual variation calculated by our theoretical electric field model and an empirical model of Richmond et al. (1980).
On the interplanetary magnetic field By control of substorm bulge expansion
Authors: Liou Kan , Meng Ching‐I , Wu Chin‐Chun
Published: September 2006

We investigate the azimuthal expansion/motion of auroral bulges in 27 large substorms using global auroral images acquired from the ultraviolet imager on board the Polar spacecraft. The region of each auroral bulge is first isolated using a region‐growing image processing technique and the location of the auroral bulge is calculated and represented by its luminosity centroid position. It is found that eastward moving auroral bulges are as common as westward moving ones during the substorm expansion phase for the events studied. To exploit the possible cause of the east‐west auroral bulge motion, we further correlate the azimuthal velocity of the auroral bulges with the dawn‐dusk component (y‐component in geocentric solar magnetic coordinates) of propagated interplanetary magnetic field (IMF) data from the Wind spacecraft. It is found that the centroid of the bulges during the expansion phase tends to move in the same direction as the y‐component of IMF. We suggest that the asymmetry in the global magnetospheric/ionospheric convection associated with a nonzero value of IMF By may be the cause of the azimuthal motion of auroral bulge.
Atmospheric controls on sea ice motion in the southern Beaufort Sea
Authors: Lukovich J. V. , Barber D. G.
Published: September 2006

The Beaufort sea ice gyre is characterized in winter months by an anticyclonic regime associated with sea level pressure (SLP) highs. Previous studies have shown instances of a reversal in this regime in summer months with the arrival of SLP lows over the Beaufort Sea, while also demonstrating a link to variations in lower stratospheric potential vorticity. In this study we examine the role of relative vorticity in describing dynamic variability on weekly timescales from the surface to the middle stratosphere. Results from this analysis show that the Beaufort Gyre is characterized predominantly by anticyclonic activity throughout the year for the time interval considered (from 1979 to 2000), with a summer reversal to cyclonic activity, whose strength and duration varies between years. These reversals coincide with reversals in SLP based on a correlation analysis. Comparison of ice and atmospheric relative vorticity fields in the Beaufort Sea region (BSR) for all weeks from 1979 to 2000 indicates that sea ice and lower tropospheric processes are anticorrelated at zero time lag. This is in contrast to relative vorticity fields at 10 mbar, which exhibit maximum correlation between stratospheric and sea ice responses when 10 mbar leads ice relative vorticity by 2–6 weeks.
Determining the dispersion characteristics of rivers from the frequency response of the system
Authors: Lambertz Peter , Palancar María C. , Aragón José M. , Gil Roberto
Published: September 2006

A new method of determining the parameters of an aggregated dead zone model (ADZ) to predict longitudinal dispersion in rivers is presented. The method is based on the frequency response analysis (FRA) of observed field tests, which consist of tracer injections (input) and measurement of tracer in downstream sampling points (output) located downstream from the injection point. The ADZ is a combination of plug and completely mixed flow compartments. The ADZ parameters (number of compartments, mean residence time, and delay time) are evaluated by means of Bode plots that give the system order (number of compartments), gain, time constant (mean residence time of each compartment) and delay time. The FRA‐ADZ method was checked with tracer data runs in two Spanish rivers, the Tagus and the Ebro rivers. The experimental tracer concentration versus time distributions were compared with the ADZ predicted curves, which were calculated using parameters obtained from the FRA method, and with curves predicted by several classical models. The residence time of several reaches within the two studied rivers was predicted by the FRA‐ADZ method with a relative error lower than 10%. The method is generally applicable to ideal and nonideal inputs and is particularly well suited to arbitrary‐shaped initial source concentration distributions.
Monsoonal reversal of remote sensing biases in latent heat flux over the eastern Arabian Sea
Authors: Muraleedharan P. M. , Pankajakshan T. , Sathe P. V. , Murty V. S. N. , Santosh K. R.
Published: September 2006

The Arabian Sea is a unique basin where a number of atmospheric and oceanographic processes occur due to the contrasting climatic conditions, which it experiences. The drastic monsoonal variability occurring in the boundary layer adversely affects the quality of remote sensing data and derived products. Comparisons of satellite‐based estimate of Latent Heat Flux (LHF) with in situ values demonstrate the nature and extent of such variabilities. Mean satellite fluxes underestimate in situ values during summer (July to September) and overestimate them during fall (October to November). The underestimation peaked for high LHF values and disappeared for low LHF during summer. During fall, maximum over‐estimation occurred when the LHF values were relatively low and it disappeared for higher LHF. These observations closely followed the behavior of satellite biases of sea surface temperature (SST) and wind speed (WS) during the two contrasting periods. Biases of SST and WS indicated opposite trends on either side of a threshold of 28.5°C and 5 m/s, respectively.
Identification of the temperature gradient instability as the source of decameter‐scale ionospheric irregularities on plasmapause field lines
Authors: Greenwald Raymond A. , Oksavik Kjellmar , Erickson Philip J. , Lind Frank D. , Ruohoniemi J. Michael , Baker Joseph B. H. , Gjerloev Jesper W.
Published: September 2006

Recent observations with the new mid‐latitude SuperDARN HF radar located at Wallops Island, Virginia have identified a class of ionospheric irregularities that is prevalent in the nightside sub‐auroral ionosphere under low‐to‐moderate Kp conditions. These irregularities can be observed for many hours and generally exhibit very low Doppler velocities. A recent collaborative experiment using the Wallops radar and the Millstone Hill incoherent scatter radar has determined that these irregularities are located at the ionospheric footprint of the plasmapause and in a region of opposed electron density and electron temperature gradients. We conclude that the irregularities are produced by the temperature gradient instability (TGI) or by turbulent cascade from primary irregularity structures produced from this instability. This is the first experimental confirmation that the TGI is effective in producing decameter‐scale ionospheric irregularities.
Direct estimation of the Rayleigh wave phase velocity in microtremors
Authors: Shiraishi Hidetaka , Matsuoka Tatsuro , Asanuma Hiroshi
Published: September 2006

We present a new estimation technique using a circular array for the Rayleigh wave phase velocity in microtremors. This technique allows us to employ more flexible sensor arrangements than that of Aki's spatial autocorrelation(SPAC) technique. One of the features is that the array output is represented by simultaneous equations consisting of complex coherence functions(CCFs). A CCF consists of two components:the Bessel function J0(r/c)(ω:angular frequency, r:radius, c:phase velocity) and an error term that varies with the azimuth of the sources. An analysis of the SPAC operation has demonstrated that the azimuthal averaging of the CCFs reduces the error term, and the average value can be approximated to J0(r/c). This result suggests the phase velocity can be determined by extracting J0(r/c) from the CCFs. Therefore, we tried to directly estimate J0(r/c) without the azimuthal averaging and developed a solution method referred to as the direct estimation method(DEM).
Mega‐pulses and megacycles in East Asian monsoon variations recorded in Chinese loess‐red clay magnetic susceptibility
Authors: Xiong Shangfa , Jiang Wenying , Liu Tungsheng
Published: September 2006

Three mega‐pulses (first order variations) and four megacycles (second order variations) in loess‐red clay magnetic susceptibility are identified in a loess section in the central Chinese Loess Plateau, implying pulsed fluctuations in East Asian monsoon intensity on tectonic timescales. Comparisons of the loess record with the mineral flux from ODP Site 758 and the diatom record in Lake Baikal core BDP‐98 suggests that the loess‐red clay magnetic susceptibility may represent a continental‐scale signal of climate change. It is apparent that the stepwise‐diachronous rise of the Tibetan Plateau and its resulting climatic influence may be the main cause of the observed monsoon pulses.
Optical observations of the development of secondary instabilities on the eastern wall of an equatorial plasma bubble
Authors: Makela J. J. , Kelley M. C. , Nicolls M. J.
Published: September 2006

Optical evidence is presented for the growth of a local secondary plasma instability on the eastern wall of an equatorial plasma bubble observed from the Haleakala Volcano, Hawaii (geographic: 20.71 N, 203.83 E; geomagnetic: 21.31 N, 271.45 E). Typically, only the western wall of depletions at tropical latitudes are susceptible to secondary structuring. This event occurs during a minor geomagnetic storm when the plasma bubble is observed to be drifting to the west, rather than with the typical eastward drift velocity. The data are interpreted in terms of the generalized E × B instability with an anomalous wind directed westward and toward the equator. This wind drives the eastern wall of the depletion region unstable. The anomalous wind is associated with an equatorward propagating neutral wind surge caused by an ongoing geomagnetic storm. The observations of the growth of these instabilities in the local tropical ionosphere are in stark contrast to the typical development of secondary instabilities on equatorial plasma bubbles, which grow near the equatorial plane on the western wall of the primary depletion and map along the magnetic field lines to off‐equatorial latitudes.
Enceladus: A significant plasma source for Saturn's magnetosphere
Authors: Pontius D. H. , Hill T. W.
Published: September 2006

The Cassini Plasma Spectrometer has reported dramatic perturbations of the magnetospheric plasma flow in a region extending at least 30 satellite radii away from Saturn's small but active icy satellite Enceladus. We interpret these observations here by means of a steady state model of the electrodynamic coupling between Enceladus and Saturn. Neutral water molecules from Enceladus are ionized, predominantly by charge exchange with ambient ions, to produce a pickup current that accelerates them to the local plasma velocity. The consequent addition of angular momentum requires Birkeland (magnetic field‐aligned) currents that couple the newly injected plasma to distant parts of the flux tube and ultimately to Saturn's ionosphere. The rate of local ionization in our model varies with the inverse square of distance from the satellite and is scaled by a free parameter proportional to the ratio of the total mass‐loading rate to Saturn's ionospheric Pedersen conductance. To explain the observed velocity perturbations, we require a total mass‐loading rate ≳100 kg/s if the conductance is ≳0.1 S as expected. If the mass‐loading region is not strongly coupled to Saturn's ionosphere, then the appropriate conductance is the Alfvén “wing” conductance ∼2 S, requiring more than an order of magnitude more mass loading. In either case, Enceladus is clearly implicated as a significant, if not dominant, source of Saturn's magnetospheric plasma.
Global trends, seasonal cycles, and European emissions of dichloromethane, trichloroethene, and tetrachloroethene from the AGAGE observations at Mace Head, Ireland, and Cape Grim, Tasmania
Authors: Simmonds P. G. , Manning A. J. , Cunnold D. M. , McCulloch A. , O'Doherty S. , Derwent R. G. , Krummel P. B. , Fraser P. J. , Dunse B. , Porter L. W. , Wang R. H. J. , Greally B. R. , Miller B. R. , Salameh P. , Weiss R. F. , Prinn R. G.
Published: September 2006

In situ observations (every 4 hours) of dichloromethane (CH2Cl2) from April 1995 to December 2004 and trichloroethene (C2HCl3) and tetrachloroethene (C2Cl4) from September 2000 to December 2004 are reported for the Advanced Global Atmospheric Gases Experiment (AGAGE) station at Mace Head, Ireland. At a second AGAGE station at Cape Grim, Tasmania, CH2Cl2 and C2Cl4 data collection commenced in 1998 and 2000, respectively. C2HCl3 is below the limit of detection at Cape Grim except during pollution episodes. At Mace Head CH2Cl2 shows a downward trend from 1995 to 2004 of 0.7 ± 0.2 ppt yr−1 (ppt: expressed as dry mole fractions in 1012), although from 1998 to 2004 the decrease has been only 0.3 ± 0.1ppt yr−1. Conversely, there has been a small but significant growth of 0.05 ± 0.01 ppt yr−1 in CH2Cl2 at Cape Grim. The time series for C2HCl3 and C2Cl4 are relatively short for accurate trend analyses; however, we observe a small but significant decline in C2Cl4 (0.18 ± 0.05 ppt yr−1) at Mace Head. European emissions inferred from AGAGE measurements are compared to recent estimates from industry data and show general agreement for C2HCl3. Emissions estimated from observations are lower than industry emission estimates for C2Cl4 and much lower in the case of CH2Cl2. A study of wildfires in Tasmania, uncontaminated by urban emissions, suggests that the biomass burning source of CH2Cl2 may have been previously overestimated. All three solvents have distinct annual cycles, with the phases and amplitudes reflecting their different chemical reactivity with OH as the primary sink.
Addiction
Authors: Treistman Steven N
Published: September 2006

Addiction refers to compulsive seeking of a class of drugs commonly referred to as drugs of abuse (because of their potential for destructive consequences to the individual). These drugs typically produce a positive emotional state following intake, and in addition, after continued drug use, may lead to negative‐feeling states in the absence of the drug.
Adrenergic Receptors
Authors: Malbon Craig C , Wang Hsien‐yu
Published: September 2006

Adrenergic receptors are cell‐surface receptors for two major catecholamine hormones and neurotransmitters that regulate key physiological responses, including cardiovascular and pulmonary function. Operating via heterotrimeric G proteins, adrenergic receptors constitute one of the most intensely studied classes of membrane proteins, whose expression and function are subject to regulation at many different levels, including transcriptional, posttranscriptional and posttranslational.
AIDS
and the Nervous System
Authors: Glass Jonathan D , Wesselingh Steven L
Published: September 2006

Infection with
Human immunodeficiency virus
(HIV) is associated with a number of neurological disorders. These disorders arise either as a result of systemic immunosuppression or due to infection with HIV itself.
Amino Acid Transporters
Authors: Kilberg Michael S , Matthews James C
Published: September 2006

Amino acid transporters are proteins that recognize and
transport free amino acids across the plasma membranes of cells. Different
families of transporters are associated with different types of amino acid,
for example cationic, anionic and zwitterionic.
Amnesia
Authors: Wingfield Arthur , Cronin‐Golomb Alice
Published: September 2006

Amnesia is a general term that refers to a serious memory
deficit typically associated with medial temporal lobe or diencephalic
lesions. Reference to amnesia implies a memory impairment in the absence of,
or out of proportion to, deficits in other intellectual domains, such as
problem solving or general cognitive function.
Astrocytes and Brain Signalling
Authors: Robitaille Richard
Published: September 2006

Astrocytes are active, receptive and complex cells that are
intimately related to neurons and synapses. They are involved in the
regulation of nerve cell activity and in processing neuronal information.
Autonomic Control
Authors: Jordan David
Published: September 2006

Autonomic reflexes are organized at the spinal and brainstem level. These homeostatic reflexes are modulated by other neural regions. The hypothalamus and forebrain organize patterns of autonomic, behavioural and endocrine responses appropriate for the stimuli evoking them.
Basal Ganglia and the Regulation of Movement
Authors: Anderson Marjorie E , Graybiel Ann M
Published: September 2006

The basal ganglia, composed of several groups of cells at the base of the cerebrum, plays an important role in the production of smoothly‐linked behaviours. The means by which information is modulated in the basal ganglia by neurotransmitters and neuromodulators released in response to expected reward and to specific motor commands is a topic of active investigation.
Bird Song: Steroid Hormones and Plasticity
Authors: Wade Juli
Published: September 2006

In many species of birds, males sing to court females and to defend territories, whereas females sing little, if at all. This behavioural sex difference is paralleled by sexual dimorphisms in neural and peripheral structures involved in song production. In adulthood, singing is generally activated by gonadal steroids, such as testosterone, but the role these hormones play in the natural development of the structural and functional sex differences is at present an intriguing mystery.
Brain Imaging as a Diagnostic Tool
Authors: Brownell Anna‐Liisa , Eidelberg David , Dhawan Vijay , Isacson Ole
Published: September 2006

Brain imaging provides anatomical and functional techniques for
experimental and clinical sciences.
Brainstem
Authors: Holstege G , Gerrits PO
Published: September 2006

The brainstem consists of several major components of the
central nervous system; including the pons, the medulla oblongata and the
mid‐brain. It is continuous with the spinal cord which it links to the
forebrain.