Entwicklungsumgebung für den rechnerunterstützten Entwurf von Mikrokomponenten

Im Rahmen dieser Arbeit wurde eine Konstruktionsumgebung für den rechnerunterstützten Entwurf mikromechanischer Komponenten auf der Grundlage des naßchemischen, anisotropen Tiefenätzens von monokristallinem Silizium entwickelt. Die Inhalte spannen einen Bogen vom Stand der Konstruktionsmethodik mikrotechnischer Systeme über die Konzeption und Implementierung einer neuen Entwurfssystematik bis hin zu deren Einsatz im Entwurf einer komplexen mikromechanischen Funktionsstruktur. Das Konzept der Umgebung trägt der Tatsache Rechnung, daß bislang kaum standardisierte mikrotechnische Bauteile am Markt verfügbar sind und sich daher primär die Aufgabe einer Neukonstruktion und Charakterisierung seiner Funktionskomponenten stellt. Die Komplexität und Heterogenität mikrotechnischer Bauelemente verhinderte bislang die einheitliche und überschaubare Integration einer rechnerunterstützten Entwicklung mikrotechnischer Komponenten und Systeme. Dem Funktionskonzept des mikrotechnischen Bauteils steht zudem vielfach ein restriktiver Einfluß der Fertigungstechnologie auf den Gestaltungsraum gegenüber. Die derzeit praktizierte, analytische Entwurfsmethodik, ausgehend vom Layout einer zweidimensionalen Maske auf die dreidimensionale (3D) Mikrostruktur zu schließen, ist daher schwierig und fehlerträchtig. Im Fall des anisotropen Ätzens gilt dieses insbesondere für komplexe Strukturen, deren Form nicht direkt aus dem Si-Kristall abgeleitet werden kann. In der Entwurfspraxis führt dies häufig zu einer Einengung des theoretisch nutzbaren Gestaltungsraums. Vor diesem Hintergrund realisiert die Konstruktionsumgebung folgende Zielsetzungen: - anwendergerechte Abbildung und Steuerung des Entwurfsablaufs anisotrop geätzter Mikrostrukturen und Dekomposition der Entwurfsaufgabe im Rahmen eines einheitlichen Integrationskonzepts der vorhandenen Entwurfswerkzeuge sowie Unterstützung einer kooperativen Aufgabenbearbeitung der Entwurfsaufgabe auf der Basis eines Workflow-Managementsystems. Das workflowbasierte Organisationskonzept der Umgebung unterstützt die einheitliche Integration weiterer domänenspezifischer Konstruktionsabläufe. - Verbesserung der Gestaltungsmethodik mikromechanischer Funktionskomponenten und Erweiterung des technologischen Anwendungsspektrums der anisotropen Ätztechnik durch die teilweise Umkehrung des klassischen Entwurfs-Grundformalismus. Grundlage ist die Entwicklung eines neuenWerkzeugs zur automatisierten Synthese lithographischer Maskenlayouts aus der 3DKomponentenbeschreibung (Layoutsynthese) auf der Basis genetischer Algorithmen. Die Layoutsynthese nutzt hierzu einen in die Konstruktionsumgebung integrierten Ätzsimulator. Das Programmsystem ist langfristig auf die Angliederung weiterer, lithographieorientierter Prozeßsimulationen ausgelegt. - Implementierung eines durchgängigen Informationsflusses im Entwurfsprozeß, ausgehend von der funktionalen Konzeption bis hin zur strukturellen Verifikation des Bauteils. Die Realisierung erfolgt im wesentlichen durch die Entwicklung einer Transformation der Ätzsimulationsergebnisse in ein Geometriemodell der Finite-Elemente-Methode auf der Grundlage rekursiver Octree- Datenstrukturen. Der Ansatz schließt die Lücke in der von der Entwurfssystematik unterstützten Wechselbeziehung einer zugleich technologie- und strukturorientierten Gestaltentwicklung mikromechanischer Funktionselemente. Zur Demonstration der Effektivität der Konstruktionsumgebung wird anhand des Entwurfs eines aus Sicht der Prozeßtechnik komplexen mikromechanischen Funktionsstruktur der Nutzen der Entwurfsmethodik und seiner Implementierung im Rahmen der vorliegenden Konstruktionsumgebung nachgewiesen. Die simulatorischen und technologischen Ergebnisse des Beispiels verdeutlichen insbesondere die erweiterten Gestaltungsmöglichkeiten anisotrop geätzter Mikrostrukturen

Inflammatory Characteristics of Stenotic Aortic Valves: A Comparison between Rheumatic and Nonrheumatic Aortic Stenosis.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Background. Although our comprehension of nonrheumatic aortic stenosis (NRAS) has increased substantially during the last decade, less is known about the histopathology of rheumatic aortic stenosis (RAS). The aim of this study was to investigate rheumatic aortic stenosis by means of analyses previously used in nonrheumatic stenosis. Material and Methods. Valve specimens were obtained from 39 patients referred to hospital due to significant aortic stenosis. According to established macroscopic criteria the valves were divided into two groups consisting of 29 NRAS and 10 RAS valves. Mononuclear inflammatory cells and apolipoproteins were investigated using immunohistochemical analyses. Results. The localisation of calcification differed in tricuspid nonrheumatic valves when compared to bicuspid nonrheumatic and rheumatic valves. The RAS valves revealed a lower degree of T lymphocyte infiltration compared with the NRAS valves. Infiltration of macrophages was seen in all valves and there were no differences regarding deposition of apolipoprotein. Conclusion. Rheumatic and nonrheumatic aortic stenotic valves show a similar and significant chronic inflammation. The similarities regarding the localisation of calcification indicate that the valve anomaly/morphology can influence the pathogenesis of aortic stenosis. Finally, our findings highlight the question of a postinflammatory valvular disease of other causes than rheumatic fever.Swedish Heart-Lung Foundation, Östergötland County Council, Linköping University Hospital

Biblioteket som udstillingsobjekt

Med udstillingen ”Design Kloden Rundt” har Kunstindustrimuseets Bibliotek frem til marts 2011 sat sig selv på museum. I transparente glasmontrer repræsenterer udstillede bøger, tidsskrifter og objekter bibliotekets samlede genstandsfelt

The low binding affinity of D-serine at the ionotropic glutamate receptor GluD2 can be attributed to the hinge region

Ionotropic glutamate receptors (iGluRs) are responsible for most of the fast excitatory communication between neurons in our brain. The GluD2 receptor is a puzzling member of the iGluR family: It is involved in synaptic plasticity, plays a role in human diseases, e.g. ataxia, binds glycine and D-serine with low affinity, yet no ligand has been discovered so far that can activate its ion channel. In this study, we show that the hinge region connecting the two subdomains of the GluD2 ligand-binding domain is responsible for the low affinity of D-serine, by analysing GluD2 mutants with electrophysiology, isothermal titration calorimetry and molecular dynamics calculations. The hinge region is highly variable among iGluRs and fine-tunes gating activity, suggesting that in GluD2 this region has evolved to only respond to micromolar concentrations of D-serine

Shuttle-box systems for studying preferred environmental ranges by aquatic animals

Animals’ selection of environments within a preferred range is key to understanding their habitat selection, tolerance to stressors and responses to environmental change. For aquatic animals, preferred environmental ranges can be studied in so-called shuttle-boxes, where an animal can choose its ambient environment by shuttling between separate choice chambers with differences in an environmental variable. Over time, researchers have refined the shuttle-box technology and applied them in many different research contexts, and we here review the use of shuttle-boxes as a research tool with aquatic animals over the past 50 years. Most studies on the methodology have been published in the latest decade, probably due to an increasing research interest in the effects of environmental change, which underlines the current popularity of the system. The shuttle-box has been applied to a wide range of research topics with regards to preferred ranges of temperature, CO2, salinity and O2 in a vast diversity of species, showing broad applicability for the system. We have synthesized the current state-of-the-art of the methodology and provided best practice guidelines with regards to setup, data analyses, experimental design and study reporting. We have also identified a series of knowledge gaps, which can and should be addressed in future studies. We conclude with highlighting directions for research using shuttle-boxes within evolutionary biology and behavioural and physiological ecology

Mannose-Binding Lectin 2 Polymorphisms Do Not Influence Frequency or Type of Infection in Adults with Chemotherapy Induced Neutropaenia

BACKGROUND: Mannose-binding Lectin protein (MBL) has been suggested to be relevant in the defence against infections in immunosuppressed individuals. In a Swedish adult cohort immunosuppressed from both the underlying disease and from iatrogenic treatments for their underlying disease we investigated the role of MBL in susceptibility to infection. METHODS: In this cross sectional, prospective study, blood samples obtained from 96 neutropaenic febrile episodes, representing 82 individuals were analysed for single nucleotide polymorphism (SNP) in the MBL2 gene. Concurrent measurement of plasma MBL protein concentrations was also performed for observation of acute response during febrile episodes. FINDINGS: No association was observed between MBL2 genotype or plasma MBL concentrations, and the type or frequency of infection. Adding to the literature, we found no evidence that viral infections or co-infections with virus and bacteria would be predisposed by MBL deficiency. We further saw no correlation between MBL2 genotype and the risk of fever. However, fever duration in febrile neutropaenic episodes was negatively associated with MBL2 SNP mutations (p<0.05). Patients with MBL2 SNP mutations presented a median febrile duration of 1.8 days compared with 3 days amongst patients with wildtype MBL2 genotype. INTERPRETATION: We found no clear association between infection, or infection type to MBL2 genotypes or plasma MBL concentration, and add to the reports casting doubts on the benefit of recombinant MBL replacement therapy use during iatrogenic neutropaenia

Identification of a Danish breast/ovarian cancer family double heterozygote for BRCA1 and BRCA2 mutations

Mutations in the two breast cancer susceptibility genes BRCA1 and BRCA2 are associated with increased risk of breast and ovarian cancer. Patients with mutations in both genes are rarely reported and often involve Ashkenazi founder mutations. Here we report the first identification of a Danish breast and ovarian cancer family heterozygote for mutations in the BRCA1 and BRCA2 genes. The BRCA1 nucleotide 5215G > A/c.5096G > A mutation results in the missense mutation Arg1699Gln, while the BRCA2 nucleotide 859 + 4A > G/c.631 + 4A > G is novel. Exon trapping experiments and reverse transcriptase (RT)–PCR analysis revealed that the BRCA2 mutation results in skipping of exon 7, thereby introducing a frameshift and a premature stop codon. We therefore classify the mutation as disease causing. Since the BRCA1 Arg1699Gln mutation is also suggested to be disease-causing, we consider this family double heterozygote for BRCA1 and BRCA2 mutations

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection