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  • Chemistry  (27,154)
  • Cell & Developmental Biology  (960)
  • ddc:330
  • Wiley-Blackwell  (28,114)
  • Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie  (25)
  • 2015-2019  (25)
  • 1970-1974  (28,114)
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  • 1
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    Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
    Publication Date: 2021-08-06
    Description: Mit fortschreitender Energiewende steigt der Anteil erneuerbarer Energien im Strommix. Deren Angebot variiert im Tagesverlauf, nach Wetterlage und saisonal. Um Angebot und Nachfrage zur Deckung zu bringen, benötigt es daher Speicher mit großen Kapazitäten. Von allen technologischen Optionen mit großer Speicherkapazität sind Wasser-Pumpspeicherwerke die einzige, die langjährig erprobt und wirtschaftlich ist. Diese könnten in Braunkohletagebauen, welche im Zuge der Energiewende aufgegeben werden, errichtet werden. Unsere Überschlagsrechnung am Beispiel eines Pumpspeicherwerks in den heutigen Tagebauen Hambach, Garzweiler und Inden zeigt, dass diese mit bis zu 400 GWh ein signifikantes technisches Speicherpotenzial haben. Dies entspricht etwa der kontinuierlichen Maximalleistung eines Kernkraftwerks über zwei Wochen. Im Kontext der Diskussion um den Braunkohleausstieg skizziert das Papier ein netzdienliches Nachnutzungskonzept für Braunkohletagebaue, das zumindest für einen Teil der heute in der Kohleförderung und -Verstromung Beschäftigten mögliche Zukunftsperspektiven bietet.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: workingpaper , doc-type:workingPaper
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  • 2
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    Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
    Publication Date: 2022-11-09
    Description: Die Autoren verdeutlichen in diesem Papier, dass der Megatrend Digitalisierung nicht zwingend unkontrollierbar über die Wirtschaft und die Gesellschaft hereinbricht. Seine Wirkung hängt vom menschlichen Verhalten, von der Gestaltung neuer Prozessen in Organisationen, aber auch Anpassungen der gesetzlichen Rahmenbedingungen ab. Dieses sozio-kulturelle, organisatorische und institutionelle Umfeld der digitalen Innovationen könne und müsse im Sinne ökologischer Nachhaltigkeit beeinflusst werden. Politik sei hier aufgefordert auf der Basis fundierter Analysen flankierend tätig zu werden. Die Autoren fordern daher, für die Digitalwirtschaft eine eigene sektorspezifische Politik zu entwickeln, wie sie für andere umweltrelevante Sektoren - etwa die Energiewirtschaft, Chemieindustrie oder Autoindustrie - bereits etabliert ist.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: workingpaper , doc-type:workingPaper
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  • 3
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    Unknown
    Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
    Publication Date: 2022-11-10
    Description: Mit fortschreitender Energiewende steigt der Anteil erneuerbarer Energien im Strommix. Deren Angebot variiert im Tagesverlauf, nach Wetterlage und saisonal. Um Angebot und Nachfrage zur Deckung zu bringen, benötigt es daher Speicher mit großen Kapazitäten. Von allen technologischen Optionen mit großer Speicherkapazität sind Wasser-Pumpspeicherwerke die einzige, die langjährig erprobt und wirtschaftlich ist. Diese könnten in Braunkohletagebauen, welche im Zuge der Energiewende aufgegeben werden, errichtet werden. Unsere Überschlagsrechnung am Beispiel eines Pumpspeicherwerks in den heutigen Tagebauen Hambach, Garzweiler und Inden zeigt, dass diese mit bis zu 400 GWh ein signifikantes technisches Speicherpotenzial haben. Dies entspricht etwa der kontinuierlichen Maximalleistung eines Kernkraftwerks über zwei Wochen. Im Kontext der Diskussion um den Braunkohleausstieg skizziert das Papier ein netzdienliches Nachnutzungskonzept für Braunkohletagebaue, das zumindest für einen Teil der heute in der Kohleförderung und -Verstromung Beschäftigten mögliche Zukunftsperspektiven bietet.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: workingpaper , doc-type:workingPaper
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  • 4
    Publication Date: 2022-11-10
    Description: Die vorliegende Arbeit verfolgt die Zielsetzung, den Beitrag verschiedener politischer Handlungsoptionen zur Steigerung der betrieblichen Energieeffizienz zu ermitteln. Eingangs wird aufgezeigt, inwieweit die Steigerung der Energieeffizienz aufgrund ihrer vielfältigen Vorteile eine Einstufung als eigenständige Zielgröße rechtfertigt im Gegensatz zu einer bloßen Betrachtung als Mittel zum Zweck des Klimaschutzes. Für die anschließende quantitative Analyse wurden Daten aus dem Projekt Energieeffizienz Impulsgespräche des Rationalisierungs- und Innovationszentrums der Deutschen Wirtschaft (RKW) e.V. aus den Jahren 2011 bis 2013 mit eigens für diese Arbeit erhobenen Daten von 2017 für dieselben Unternehmen verglichen. Zu diesem Zweck wird ein difference-in-differences-Ansatz genutzt. Im Ergebnis erweisen sich Preise im Gegensatz zu anderen Maßnahmen wie Energieberatungen, Fördermitteln und Energiemanagementsystemen als zumindest teilweise wirksame Einflussgröße für die Energieeffizienz. Der Autor empfiehlt auf dieser Basis eine stärker marktwirtschaftlich ausgerichtete Effizienzpolitik.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 5
    Publication Date: 2022-11-10
    Description: Im Rahmen des Forschungsprojekts "Wirtschaftsförderung 4.0" leistet die vorliegende Arbeit einen Beitrag zum besseren Verständnis der systematischen Stärkung zivilgesellschaftlicher Nachhaltigkeitsinitiativen. Das Ziel der Analyse besteht darin, Ansatzpunkte möglicher Unterstützungsmaßnahmen aufzuzeigen, die im Zuge kommunaler Wirtschaftsförderung aufgegriffen werden können. Zur Erarbeitung wurden zunächst mithilfe theoretischer Grundlagen aus der Transition- und Diffusionsforschung zentrale Einflussfaktoren zusammengetragen, die förderlich oder hemmend auf transformative Nachhaltigkeitsinitiativen wirken können. Mit dem Ziel, kontextangepasste Maßnahmen zu entwickeln, wurden die literaturbasierten Faktoren anschließend in einer qualitativen Befragung mit einer Praxisperspektive verglichen und ergänzt: Mittels leitfadengestützter Experteninterviews mit nachhaltigkeitsorientierten Initiativen in der Region Osnabrück wurden kommunale Gegebenheiten sowie die jeweiligen Erfolgsfaktoren, Herausforderungen und Bedarfe der Graswurzelinitiativen erfasst. Im Ergebnis zeigen sich sieben übergreifende Bedarfsfelder, die vor allem aus der empirischen Erhebung abgeleitet wurden. Aus ihnen wurden Handlungsempfehlungen und Ansatzpunkte kommunaler Unterstützung erarbeitet und diskutiert.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 6
    Publication Date: 2021-05-04
    Description: Germany's waste management system is one of the world's most advanced - its primary objective is to dispose of waste in a way that is safe for both people and the environ- ment. However, only about 14 per cent of the raw materials used in industry are derived from recycling processes; the remainder are still sourced from primary materials. The circular economy is not yet being implemented on a large enough scale. Recyclates or recycled materials, i.e. secondary raw materials recovered from waste, are being fed back into production and usage processes at volumes that are far below what is possible. If this system were to be improved, loss of value, dependence on volatile commodity markets, lower resource productivity, and externalities in the form of environmental pollution could be avoided. A drive towards digitalisation in industry and the waste management sector could make this happen. A study by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) indicates that no other lead market in the environmental sector stands to benefit from digitalisation more than the circular economy - and that, at the same time, no sector has ever been so poorly positioned.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
    Type: workingpaper , doc-type:workingPaper
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  • 7
    Publication Date: 2022-02-18
    Description: Eine Kosten-Nutzen-Analyse ist ein bewährtes Mittel, um die Rentabilität einer Energieeffizienzmaßnahme zu bewerten: Die Investitionskosten werden mit den eingesparten Energiekosten verglichen. Investitionsentscheidungen für Energieeffizienzmaßnahmen erfolgen allerdings häufig nicht nach einer reinen Erwägung der direkten Kosten und Nutzen. Gründe hierfür sind unter anderem "versteckte" Kosten und Risiken (z. B. Kosten für die Beschaffung von Informationen, Unsicherheiten über zukünftige Energiepreise und Einsparungen), aber auch nicht-monetäre Hemmnisse, die bei Entscheidungen eine Rolle spielen (z. B. beschränkte Rationalität, Präferenzen, Zeitverfügbarkeit). Vor diesem Hintergrund verfolgt der Bericht das Ziel, ein besseres Verständnis der Kosten-Nutzen-Erwägungen von Investoren und deren Entscheidungswirklichkeit zu erlangen. Die Untersuchung zeigt, dass Energieeffizienzdienstleistungen (EEDL) generell die versteckten Kosten - Transaktionskosten - reduzieren können. Das setzt aber voraus, dass EEDL sachgerecht durchgeführt werden. Transaktionskosten werden allerdings im Zusammenhang mit Energieeffizienzmaßnahmen von den Akteuren kaum wahrgenommen und entsprechend nicht quantifiziert. Des Weiteren zeigt sich, dass insbesondere bei Unternehmen die EEDL-Kosten für bestimmte Maßnahmen hoch sein können. Doch werden gerade in diesen Fällen die Transaktionskosten reduziert. Grundsätzlich erscheinen kostenaufwendigere EEDL, wie umfassendere Vor-Ort-Beratungen, im Gegensatz zu den preiswerteren Vor-Ort-Checks besser geeignet, um Transaktionskosten zu reduzieren.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: report , doc-type:report
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  • 8
    Publication Date: 2022-02-18
    Description: Dieses Inputpapier soll für japanische Entscheidungsträgerinnen und -träger aufzeigen, was die Hintergründe der in Deutschland zu beobachtenden Welle an Stadtwerke-Neugründungen und Rekommunalisierungen sind. Dabei wird auf aktuelle energiewirtschaftliche Entwicklungen und Rahmenbedingungen in Deutschland eingegangen, die ein besseres Verständnis vermitteln werden. Das Inputpapier soll vor allem japanische Kommunalpolitikerinnen und -politiker in die Lage versetzen, in ihren eigenen Gemeinden fundierte Diskussionen über eine mögliche Stadtwerkegründung zu führen und Entscheidungen vorzubereiten. Dies können sie auf Basis wichtiger Grundkenntnisse und Erfahrungen deutscher Städte und Gemeinden initiieren. Im Laufe des Gesamtprojektes wird im Herbst 2018 ein Werkzeugkasten entwickelt, der zur Unternehmens-Neugründung in Japan wichtige Hilfestellungen wird leisten können. Ergänzend dazu bleiben juristische und energiewirtschaftliche Fachberatungen unerlässlich, um einen erfolgreichen Start der neuen kommunalwirtschaftlichen Unternehmen zu gewährleisten. Dieses Inputpapier versteht sich daher als erste Handreichung und Hilfestellung für kommunale Entscheidungsträgerinnen und -träger in Japan, damit dort ein Grundverständnis des "Stadtwerkeprinzips" entstehen kann.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 9
    Publication Date: 2022-02-18
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 10
    Publication Date: 2022-02-18
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: Japanese
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  • 11
    Publication Date: 2022-11-09
    Description: Deutschland verfügt über eines der weltweit führenden Systeme im Bereich der Abfallwirtschaft - vorrangiges Ziel ist es, Abfall sicher und umweltschonend zu entsorgen. Allerdings kommen nur ca. 14 Prozent der in der Industrie eingesetzten Rohstoffe aus dem Recycling, der Rest sind noch immer Primärmaterialien. Kreislaufwirtschaft findet noch nicht ausreichend statt: Rezyklate, aus Abfällen gewonnene Sekundärrohstoffe, werden noch weit unterhalb der möglichen Mengen in Produktions- und Nutzungsprozesse zurückführt. Werteverlust, Abhängigkeit von volatilen Rohstoffmärkten, geringere Ressourcenproduktivität und Externalitäten in Form von Umweltverschmutzung ließen sich damit vermeiden. Eine Digitalisierungsoffensive in Industrie und Abfallwirtschaft könnte dies bewirken. Eine Studie des Bundesministeriums für Umwelt, Naturschutz, Bau und Reaktorsicherheit (BMUB) verweist darauf, dass kein Umweltleitmarkt so stark von der Digitalisierung profitieren könnte wie die Kreislaufwirtschaft - und dass gleichzeitig kein Sektor bisher so schlecht aufgestellt ist.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 12
    Publication Date: 2022-11-10
    Description: Stadtwerke spielen für die Energiewende eine zentrale Rolle. Zum einen stellen sie in Deutschland weit über die Hälfte der Versorgung an Strom, Gas und Wärme sicher, zum anderen haben Stadtwerke aufgrund ihrer kommunalen Verankerung eine besondere Position im Spannungsgefüge von Politik, Wirtschaft und Privathaushalten. Wenn es aber um die Frage geht, was den Erfolg von neugegründeten Stadtwerken ausmacht, besteht in der Literatur in gewissem Maße eine Forschungslücke. Die vorliegende Studie, die vom Wuppertal Institut und der BLUBERRIES GmbH gemeinsam erstellt wurde, behandelt ausgewählte Handlungsfelder, bei denen ein Einfluss auf den Unternehmenserfolg von neugegründeten Stadtwerken zu vermuten ist. Dabei werden als Rahmen die Ziele der Rekommunalisierung herangezogen und konkret vier Handlungsfelder in den Vordergrund gerückt. Der Fokus der Studie liegt auf Fragestellungen nach dem wirtschaftlichen Erfolg neugegründeter Stadtwerke sowie deren Zielerreichung. Dabei wird auf den klassischen Ansatz der Erfolgsfaktorenforschung zurückgegriffen. Ziel dieser Studie ist die Formulierung erster Aussagen darüber, wie einerseits die unterstellten Handlungsfelder in ihrer Ausgestaltung, andererseits die Erfolgsmaße durch neugegründete Stadtwerke beurteilt werden. Aufgrund der im Rahmen dieser Untersuchung vorgenommenen Online-Befragung lassen sich für die in den Focus genommenen vier Handlungsfelder (Kooperationen, Digitalisierung, Resilienz und Soziale Verantwortung) die wichtigsten Ergebnisse wie folgt zusammenfassen: Kooperationen und verschiedene Formen der Zusammenarbeit in der Gründungsphase spielen für den Erfolg neu gegründeter Stadtwerke eine sehr große Rolle. Neu gegründete Stadtwerke legen meist großen Wert auf nachhaltige Geschäftsbeziehungen zu örtlichen Unternehmen, was einen wesentlichen Beitrag zum Public Value darstellt. Insbesondere gut ausgearbeitete Geschäftsstrategien in den Bereichen Erneuerbare Energien, Verteilnetzbetrieb, Vertrieb und Diversifikation unterstützen die Umsetzung der Unternehmensziele in Bezug auf Resilienz und Nachhaltigkeit. Die eher durchschnittliche Bewertung der Resilienz-Relevanz für den Ausbau eines Smart Grids im Verteilnetzbereich ist ein Indiz dafür, dass der Ordnungsrahmen so geändert werden müsste, dass Investitionen in diesem Bereich attraktiver werden. Aufgrund des explorativen Charakters der vorgelegten Studie, der keine repräsentativen Aussagen über die Erfolgsfaktoren von neugegründeten Stadtwerken zulässt, werden folgende vier Hypothesen abgeleitet: 1. Der Einsatz von horizontal-kooperativen Ansätzen in der Gründungsphase als ein spezifisches Wesensmerkmal der deutschen Stadtwerkelandschaft hat positive Auswirkungen auf die Verbesserung des wirtschaftlichen Erfolgs und der Rentabilität. 2. Der Fokus auf Resilienz, Nachhaltigkeit und Klimaschutz als zentrale Werte des Stadtwerks und als integrale Bestandteile des Unternehmensleitbildes unterstützt die Erreichung der strategischen Ziele des neugegründeten Stadtwerks. 3. Das Anbieten von Smart Metern zur Erhöhung der Kundentransparenz, zur Verbesserung des Kundennutzens und zur Optimierung des Verteilnetzmanagements kann als Erfolgsfaktor eingestuft werden und unterstützt seitens der Stadtwerke eine positive Unternehmensentwicklung nicht nur in der Startphase. 4. Die explizite Wahrnehmung von sozialer Verantwortung wirkt sich positiv auf den Unternehmenserfolg aus. Es müsste nun anschließend auf der Basis einer größeren Grundgesamtheit geprüft werden, ob und inwieweit die beschriebenen Tendenzen (die sich aus der Online-Befragung ergeben) und die explorativen Hypothesen im Rahmen eines konfirmatorischen Untersuchungsansatzes wissenschaftlich verifiziert werden können.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: report , doc-type:report
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  • 13
    Publication Date: 2022-11-10
    Description: Seit Mitte der 2000er Jahre ist in Deutschland ein Großteil der Konzessionsverträge für örtliche Strom-Verteilnetze ausgelaufen. Dies eröffnete den Kommunen vielerorts die Möglichkeit ihre bis dahin in privatem Besitz befindlichen Strom-Verteilnetze zu rekommunalisieren. Vor dem Hintergrund der Energiewende und dem damit einhergehenden Umbau der deutschen Energielandschaft hin zu dezentralen Versorgungsstrukturen eröffnete sich kommunalen Verantwortlichen so die Möglichkeit die Umsetzung energiepolitischer Ziele der Bundesregierung auf kommunaler Ebene aktiv mitzugestalten. Eine im Jahr 2013 durch das Wuppertal Institut durchgeführte Sondierungsstudie erfasste für den Zeitraum 2005 bis 2016 zahlreiche Stadtwerke-Neugründungen, welche einen Trend zur Rekommunalisierung im Bereich der Energieversorgung andeutete. Darüber hinaus versuchen sich Institutionen wie das Deutsche Institut für Urbanistik (Difu) und der Verband kommunaler Unternehmen e.V. (VKU) bereits seit Jahren einen Überblick über die Entwicklung von Rekommunalisierungen zu verschaffen. Trotzdem existiert bis heute keine flächendeckende Erhebung über Rekommunalisierungen in Deutschland. Ziel dieser Arbeit war es daher eine Bestandsaufnahme über die Rekommunalisierung von Strom-Verteilnetzkonzessionen im Untersuchungsraum Nordrhein-Westfalen zwischen 2005 und 2016 vorzunehmen. In diesem Zeitraum konnten für den Untersuchungsraum insgesamt 119 Rekommunalisierungen festgestellt werden. Damit lagen bis Ende 2016 bereits zwei Drittel aller nordrhein-westfälischen Strom-Verteilnetzkonzessionen in kommunaler Hand, womit der Trend zur Rekommunalisierung eindeutig belegt werden konnte.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 14
    Publication Date: 2022-02-18
    Description: Kern des Projektes war es zu untersuchen, wie der Untersuchungsraum in Bezug auf die Energiewende aufgestellt ist und welche Entwicklungspotenziale künftig im Zuge einer gesellschaftlich und politisch gewollten Energiewende genutzt werden können. Zur Qualifizierung des wissenschaftlichen Nachwuchs wurde im Rahmen der hier bearbeiteten Forschungsfragen Studierende darin angeleitet, im Bereich der energiebezogenen Transformationsforschung eigenständig Teilaspekte zu untersuchen. Dementsprechend wurden vom Wuppertal Institut insgesamt vier Studienarbeiten mit verschiedenen Themenschwerpunkten ausgeschrieben. Diese sollten am konkreten Beispiel der zu untersuchenden Region aufzeigen, welche Stärken und Schwächen, aber auch Chancen und Risiken in Bezug auf die pro-aktive Gestaltung der Energiewende bestehen. Zusätzlich sollte untersucht werden, wie stark kleine und mittlere Unternehmen (KMU) in der Region Unna davon betroffen sind beziehungsweise inwieweit sie als Akteure der Energiewende die Nachhaltigkeit ihrer unternehmerischen Tätigkeit stärken und sichern können. Auch die regionalwirtschaftlichen Effekte wie Wertschöpfungs- und Arbeitsplatzeffekte, die erzielbar wären, wenn die mittelständischen Unternehmen der Region pro aktiv die Herausforderungen der Energiewende in den Bereichen Energieeffizienz, erneuerbare Energien und dezentrale KWK aufgreifen, waren Bestandteil der Studienarbeiten. Der Schwerpunkt lag hier insbesondere im Bereich Energieeffizienz.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 15
    Publication Date: 2022-02-18
    Description: Mit der Nachhaltigkeitsanleihe NRW erschließt das Land das international wachsende Segment des nachhaltigen Investments für die Kreditfinanzierung des Landeshaushalts. Ziel der vorliegenden Studie ist es, die Bewertung positiver Nachhaltigkeitseffekte für die in 2016 emittierte Nachhaltigkeitsanleihe NRW zu erproben und Handlungsempfehlungen zur Bewertung zukünftiger Nachhaltigkeitsanleihen zu entwickeln. Für eine umfassende Nachhaltigkeitsanalyse ist aufgrund der Vielschichtigkeit der finanzierten Projekte und fehlender Standards zur Bewertung sozialer Kriterien eine umfangreiche Untersuchung erforderlich, wodurch sie für eine regelmäßige und standardisierte Wirkungsanalyse zukünftiger Anleihen nicht in Frage kommt. Stattdessen verfolgt die vorliegende Studie einen pragmatischen Ansatz zur Bewertung. Der Fokus liegt auf der Evaluation der potenziellen Treibhausgas-Minderung (THG-Minderung), da deren Bewertung sich derzeit als Standard für eine Wirkungsanalyse solcher Anleihen abzeichnet. Darüber hinaus werden die nächsten Schritte für eine Weiterentwicklung der Methodik und des Indikatorensets im Rahmen zukünftiger Wirkungsanalysen aufgezeigt.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 16
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    Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
    Publication Date: 2022-11-10
    Description: Seit 2005 ist ein Großteil der deutschen Strom- und Gaskonzessionsverträge ausgelaufen und eröffnete vielen Kommunen die Chance, die Energieversorgung wieder in die eigenen Hände zu nehmen. Gleichzeitig übernimmt die kommunale Ebene in einem zunehmend dezentral strukturierten Energieversorgungssystem eine immer wichtigere Rolle, da die Umsetzung der energiepolitischen Ziele der Bundesregierung vor allem vor Ort, in den Kommunen stattfindet. Ziel dieser Arbeit war es daher, zu ermitteln wie viele Kommunen im Zeitraum von 2005 bis 2016 durch die Gründung neuer Unternehmen im Bereich der Energieversorgung tätig geworden sind und welche Rolle die kommunalen Energieversorgungsunternehmen im Rahmen der Energiewende einnehmen können. Auf Grundlage der bereits 2013 vom Wuppertal Institut durchgeführten Sondierungsstudie, die zahlreiche Neugründungen bis 2012 erfasste, konnten in dieser Arbeit insgesamt 139 kommunale Energieversorgungsunternehmen ermittelt werden, deren Gründung zwischen 2005 und 2016 stattfand. Dieses Ergebnis belegt für diesen Zeitraum einen ausgeprägten Trend zur Rekommunalisierung im Bereich der Energieversorgung. In einer umfangreichen Literaturanalyse sowie acht Experteninterviews mit kommunalen Ansprechpartnern und Geschäftsführern junger Stadtwerke, konnte darüber hinaus belegt werden, dass die kommunalen Energieversorger aufgrund ihrer Fachexpertise und ihrer ausgeprägten Vernetzung mit den Bürgern, örtlichen und regionalen Akteuren und der Kommune, wichtige Instrumente zur Umsetzung kommunaler Klimaschutzziele darstellen. Sie sind nicht nur in der Lage, sich im energiewirtschaftlichen Wettbewerb zu beweisen und zu positionieren, sondern können aufgrund ihrer lokalen Verankerung auch Potenziale erschließen, die von privaten Versorgern weitgehend ungenutzt bleiben. Diese umfassen beispielsweise Potenziale zur Energieerzeugung und -einsparung auf Kundenseite, aber auch die Möglichkeiten regenerativer Wärmeversorgung durch Nah- oder Fernwärme und eine stärkere Beteiligung der Bürger. Neben den zusätzlichen Wertschöpfungseffekten, von denen die Kommunen profitieren, ermöglichen die kommunalen Energieversorgungsunternehmen somit auch die aktive Mitgestaltung der Energiewende vor Ort, unter Einbeziehung der lokalen Akteure und Bürger.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 17
    Publication Date: 2022-11-10
    Description: Stadtwerke sind im Ruhrgebiet strukturprägend und haben eine lange Tradition. Sie sind fester Bestandteil der Akteurskonstellation im Energiebereich der Emscher-Lippe-Zone. Schon heute zeichnen sich die Stadtwerke des Ruhrgebiets vielfach dadurch aus, dass sie die mit der Energiewende verbundenen Chancen nutzen. Ihre technische und gesellschaftliche Struktur entspricht weitgehend den mit der Energiewende verbundenen Transformationsprozessen hin zu einer stärkeren Dezentralität der Erzeugung und der Demokratisierung der Energieversorgung. Die meisten Stadtwerke des Ruhrgebiets sind auf mehreren Wertschöpfungsstufen im Energiebereich tätig. In der Stromerzeugung haben sie einen Schwerpunkt im Bereich der Kraft-Wärme-Kopplung und bei erneuerbaren Energien. Zudem sind sie vielerorts Partner und teilweise sogar Mitinitiator bürgerschaftlichen Engagements zum Ausbau erneuerbarer Energien. Als Verteilnetzbetreiber für Strom, Gas und Wärme sorgen sie vielerorts für die Integration und Verteilung erneuerbarer Energien. Die Energiewende findet weitgehend in den örtlichen Verteilnetzen statt und bedeutet für die Stadtwerke des Ruhrgebiets eine Zunahme an komplexen Koordinierungsfunktionen und teilweise auch die Herausbildung völlig neuer Aufgaben.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 18
    Publication Date: 2022-11-10
    Description: Die Energiewende gilt als eine der zentralen gesellschaftlichen Projekte unserer Zeit. Ihre Bedeutung beschränkt sich nicht nur auf ihren bekannten Beitrag zum globalen Klimaschutz und auf die Reduzierung der Gefahren durch den Gebrauch von Atomenergie. Sie soll auch dazu dienen, die Energieimportabhängigkeit Deutschlands, mögliche Auswirkungen von Energiepreisschocks und die Wahrscheinlichkeit der Einbeziehung in zukünftige Ressourcenkriege zu reduzieren. Neben diesen Schutzfunktionen kann sie aber auch neue Geschäftsfelder und Arbeitsplätze schaffen und Innovationen in den Bereichen Effizienz und erneuerbare Energien voranbringen und damit einen Beitrag zu einer zukunftsorientierten, ökologischeren wirtschaftlichen Entwicklung beitragen. Bereits 2010 hat die Bundesregierung Ziele in Bezug auf den Ausbau erneuerbarer Energien, die Steigerung der Energieeffizienz sowie die Reduktion des CO2-Ausstoßes formuliert. Während die Ziele hinsichtlich des Ausbaus erneuerbarer Energien im Stromsektor und am Wärmeverbrauch voraussichtlich erreicht werden, sind im Bereich der Energieeffizienzsteigerung weitere Anstrengungen notwendig. Zwar gibt es zahlreiche Energiedienstleistungsangebote und Förderprogramme, mit denen die Energieeffizienz gesteigert werden sollen, allerdings haben diese - insbesondere bei kleinen und mittleren Unternehmen (KMU) - bisher nicht zu den gewünschten Ergebnissen geführt. Daher ist es Ziel der Arbeit, Ansätze für ein Konzept zur Realisierung von Energieeffizienzpotentialen in KMU zu entwickeln. Der Untersuchungsraum der Arbeit liegt im östlichen Ruhrgebiet in der Region Unna/Kamen/Bergkamen/Bönen/Holzwickede und ist auf das Projekt "SWOT-Analyse zur Energiewende Unna/Kamen/Bergkamen/Bönen/Holzwickede“ des Wuppertal Instituts zurückzuführen, in dessen Rahmen diese Arbeit entstand. Im Zuge der Analyse wurden zentrale interne und externe Einflussfaktoren auf die Entscheidung regionaler KMU zur Durchführung von Energieeffizienzmaßnahmen analysiert sowie Praxisbeispiele zur Realisierung von Energieeffizienzpotentialen ausgewertet. Abschließend wurden die Analyseergebnisse zu ersten Ideen für ein Konzept zur Realisierung von Energieeffizienzpotentialen in KMU ausgearbeitet und als Handlungsempfehlungen formuliert.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 19
    Publication Date: 2021-05-04
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 20
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    Wiesbaden : Springer VS | Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
    Publication Date: 2018-11-19
    Description: Alexandra Seibt untersucht Wirtschaftsverbände im Längsschnitt anhand eines Mehrmethodendesigns, bestehend aus Dokumentenanalysen, Inhaltsanalysen und teilstandardisierten Leitfadeninterviews. Die Autorin kann bei den Verbänden einen zunehmenden kombinierten Einsatz von öffentlichen und nicht öffentlichen Kommunikationsstrategien im Sinne des PA-Managements nachweisen. Verbände nutzen hierbei - wie Protestgruppen und NGOs - die Öffentlichkeit, um über die externe Kommunikation Aufmerksamkeit und Zustimmung für ihre Interessen im politischen System zu generieren. Als Fallbeispiel dienen die Verbände der Branche der erneuerbaren Energien während der Novellierungen zum Erneuerbare-Energien-Gesetz.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: doctoralthesis , doc-type:doctoralThesis
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  • 21
    Publication Date: 2018-11-19
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 22
    Publication Date: 2022-02-18
    Description: Die Produktion von Kunststoffen ist eine Geschichte extremen Wachstums: waren es global 1950 noch 1,7 Millionen, sind es 2012 weltweit 288 Millionen Tonnen (Mt). 57 Mt davon werden in der EU erzeugt mit einem gleichzeitigen Abfallvolumen von 25 Mt. Einher gehen hohe Verbräuche fossiler Rohstoffe mit entsprechenden Umweltbelastungen und massiven Schäden, die durch Plastikmüll verursacht werden. Das Wuppertal Institut hat im Auftrag des Naturschutzbunds Deutschland (NABU) untersucht, wie sich dieser Wachstumstrend in Deutschland ohne Gegensteuerung fortsetzen wird und mit welchen Strategien die Plastikflut eingedämmt werden kann. Die Autoren der Studie errechneten einen Steigerung um 28 Prozent bis zum Jahr 2030, insbesondere in den Bereichen Verpackungen und Bau. Für die künftig wichtigsten Anwendungsbereiche wurden in der Studie jeweils drei konkrete Ansätze zur Verringerung des Kunststoffeinsatzes aus den Bereichen Industrie, Handel und Haushalte ausgewählt. Diese neun Optionen wurden an Fallbeispielen auf ihre Vor- und Nachteile und die grundsätzliche technische, rechtliche und ökonomische Machbarkeit hin diskutiert. Umsetzungsansätze liefert die Studie für den politischen Raum, für Unternehmen und den privaten Konsum.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
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  • 23
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    München : Oekom-Verl. | Wuppertal : Wuppertal Institut für Klima, Umwelt, Energie
    Publication Date: 2022-02-18
    Description: Unternehmen sind heutzutage mit einer Vielzahl von Herausforderungen und Veränderungen konfrontiert, die zugleich Chance und Risiko für ihre wirtschaftliche Weiterentwicklung darstellen. Dazu gehören nicht nur grundlegende Trends wie Klimawandel, Ressourcenknappheit oder Urbanisierung, sondern auch der Wandel von Technologien, Geschäftsmodellen, gesetzlichen Rahmenbedingungen oder der gesellschaftlichen Akzeptanz. All dies hat globale und nationale Veränderungen in Märkten zur Folge und stellt die darin operierenden Unternehmen vor konkrete Herausforderungen. Die Auseinandersetzung mit der Zukunft gewinnt somit immer mehr an Bedeutung und stellt einen wichtigen Faktor für den langfristigen und nachhaltigen Erfolg eines Unternehmens dar. Die Strategische Frühaufklärung unterstützt Unternehmen dabei, Herausforderungen und Veränderungen rechtzeitig zu identifizieren und darauf zu reagieren. Stefan Reicherz erstellt eine flexible Blaupause hierfür: Individuell an ein Unternehmen angepasst, liefert sie diesem die notwendigen Informationen und Hilfsmittel, um erfolgreiche Strategische Frühaufklärung durchzuführen - und damit aus Risiken Chancen werden zu lassen.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: doctoralthesis , doc-type:doctoralThesis
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  • 24
    Publication Date: 2022-02-18
    Description: Ziel dieser Studie ist es, einen aktuellen Überblick über den Stand der Recyclingwirtschaft in Deutschland zu geben. Der Fokus liegt dabei vor allem auf den Marktprozessen, die bereits heute ökonomische Anreize zur Schließung von Stoffkreisläufen geben, bzw. auf spezifischen Hemmnissen, die genau solchen Entwicklungen im Wege stehen. Aufbauend auf der Analyse spezifischer Hemmnisse für einzelne Abfallfraktionen (rechtliche und institutionelle Hemmnisse, Marktmacht, Informationsdefizite etc.) leitet die Studie verschiedene Instrumente und handlungsorientierte Ansätze ab, die zu einer Verbesserung der Kreislaufführung beitragen könnten; dabei kann Deutschland auch von bestehenden Best-Practice-Ansätzen im Ausland profitieren. Dazu gehören unter anderem der verstärkte Einsatz ökonomischer Instrumente, Maßnahmen zur verstärkten Integration von Abfallwirtschaft und Produktionssektor, Urban Mining Konzepte, internationale Vereinbarungen zum Rohstoffrecycling sowie Green Tech Funds.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 25
    Publication Date: 2022-11-10
    Description: Dieses Wuppertal Paper befasst sich mit folgenden Leitfragen: Wie wichtig sind Stadtwerke für die Energiewende? Was sind dabei die besonderen Beiträge von Stadtwerken? Hier ist insbesondere zu berücksichtigen, dass kommunal betriebene Kraft-Wärme-Kopplungs-Anlagen (KWK-Anlagen) ein wichtiger Komplementär zum Ausbau der erneuerbaren Energien darstellen und dass kommunale KWK-Anlagen inzwischen einen nennenswerten Beitrag zur Sicherstellung der Residuallast liefern. Zudem geht es um die Leitfrage, welche Rahmenbedingungen die Rolle von Stadtwerken als zentrale Akteure der Energiewende und insbesondere als Betreiber von KWK-Anlagen erschweren.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 26
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 1-27 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We describe a method for determining chemical kinetic constants and diffusion coefficients by measuring the rates of decay of spontaneous concentration fluctuations. The equilibrium of the system is not disturbed during the measurement. We measure the number of molecules of a specified type in a defined open volume as a function of time and compute the time course of the deviations from the thermodynamic mean concentration. The method is based on the principle that the rates of decay of spontaneous microscopic fluctuations are determined by the same phenomenological rate coefficients as those of macroscopic departures from equilibrium which result from external perturbations. Hence, an analysis of fluctuations yields the same chemical rate constants and diffusion coefficients as are measured by conventional procedures. In practice the number of the specified molecules is measured by a property such as absorbance or fluorescence which is specific and sensitive to chemical change. The sample volume is defined by a light beam which traverses the cell. As the molecules appear in or disappear from the light beam, either due to diffusion or chemical reaction, their concentration fluctuations give rise to corresponding fluctuations of the intensity of absorbed or emitted light. This paper presents the theory needed to derive chemical rate constants and diffusion coefficients from these fluctuations in light intensity. The theory is applied to three examples of general interest: pure diffusion in the absence of chemical reaction; the binding of a small rapidly diffusing ligand to a larger slowly diffusing macromolecule; and a unimolecular isomerization. The method should be especially useful in studying highly cooperative systems, relatively noncooperative systems with intermediate states closely spaced in free energy, small systems, and systems not readily subject to perturbations of state.
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  • 27
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    Biopolymers 13 (1974), S. 97-114 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular conformations and dynamics of poly(L-prolyl), poly(hydroxyl-L-prolyl), poly(L-prolyl-glycyl), poly(hydroxyl-L-prolyl), and poly(glycyl-glycyl-L-prolyl-glycyl), in aqueous solution, have been studied using 13C pulse Fourier transform nmr spectroscopy. From a measurement of the intensities of major and minor resonances in the spectra of the copolypeptides, it was determined that 15-20% of the glycyl-prolyl and glycyl-hydroxyprolyl peptide bonds are cis. Effective rotational correlation times (τeff), obtained from measurements of spin-lattice relaxation times (T1) of individual backbone and side-chain carbons, demonstrated that backbone reorientation is approximately isotropic for the five polypeptides and is characterized by correlation times of ca. 0.3-0.6 nanoseconds as a result of rapid segmental motion. In a given polypeptide glycyl and pyrrolidine residues were found to have the same backbone correlation times, but backbone carbon τeff values did decrease as the glycyl content of the peptides increased. A semi-quantitative analysis of Cβ, Cγ, and Cδ correlation times suggests that rapid ring motion in both prolyl and hydroxyprolyl involves primarily Cγ and Cβ, with the prolyl ring being more mobile than the hydroxyprolyl ring.
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  • 28
    Electronic Resource
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    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 237-238 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No. Abstract.
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  • 29
    Electronic Resource
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    Biopolymers 13 (1974), S. 217-226 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A model for the flexibility of DNA is proposed that is based on discrete variations in the direction of propagation in going from one subunit to the next. Expansion of the local free energy in terms of the local bending gives a Gaussian distribution function. The assumption of the independence of local bends on neighbors lead to very simple formulae for the persistence length and the characteristic ratio. Emphasis, however, is placed on the application of the formulae for molecules of finite size where the persistence length and C∞ are not defined. The formulae are worked out for two models, which should serve as limits for the real physical situation.
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  • 30
    Electronic Resource
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    Biopolymers 13 (1974), S. 735-743 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: If dispersion effects are not taken into account, the dimensions of particles in suspension estimated from spectrophotometric data (slope of the log OD versus log λ plot) are too low. By measuring dispersion curves for the medium and for the suspension, a consistent estimate of the size of latex particles of different diameter is obtained from the OD data.
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  • 31
    Electronic Resource
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    Biopolymers 13 (1974), S. 765-768 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helix-coil transition of poly-N5-(3-hydroxypropyl)-L-glutamine in methanol-water solutions has been observed using 13C nuclear magnetic resonance. Two signals appear in the α-CH region in the course of the transition; this is in contrast with previous proton magnetic resonance experiments carried out on this polymer in the same solvent system.
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  • 32
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    Biopolymers 13 (1974), S. 779-790 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: X-ray diffraction and stereochemical analyses were used to study the hydrated structure of the helical amylose polymorph having a fiber repeat spacing of 8 Å. Intensity calculations using computer models confirmed six as the number of residues per turn and supported the space group P212121. Both diffraction intensity and stereochemical methods indicate the suitability of residue G3 from the potassium acetate complex of cyclohexaamylose as opposed to residues with longer O(4)-O(1) vectors. Comparison of the present results with those obtained for V amylose dehydrate indicated no major conformational differences between the two helix skeletons. A net helical rotation of approximately 30° accompanied the hydrate-dehydrate transition and the rotational position in the hydrate allowed packing that was less close. Hydration water molecules were not located; noncarbohydrate peaks on the electron density maps were primarily due to Fourier series termination errors.
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  • 33
    Electronic Resource
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    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 843-852 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have measured the circular dichroism spectra and have obtained melting curves for samples of purified satellite DNA's from three species of crab, Cancer borealis, Gecarcinus lateralis, and Callinectes sapidus. Although all three satellite DNA's have the same density in neutral CsCl, their circular dichroism spectra and melting and reassociation characteristics are different, as are other properties of these DNA's. The circular dichroism spectra are analyzed to give estimates of nearest-neighbor frequencies. We estimate that about 90% of the Cancer borealis satellite DNA and over 80% of the Gecarcinus lateralis satellite DNA consist of d(AT)n:d(AT)n sequences, while the serially repeating unit of the Callinectes sapidus satellite DNA may not contain any extended d(AT)n:d(AT)n sequences. The results from the circular dichroism spectra for the Cancer borealis, Gecarcinus lateralis, and the Callinectes sapidus satellite DNA's are in agreement with base composition analyses, which give 2.4, 8, and 25% G+C, respectively, for these DNA's.
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  • 34
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    Biopolymers 13 (1974), S. 879-890 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Samples of epichlorohydrin crosslinked potato starch were prepared by using a high ratio of starch to water and alkali concentration below the gelatinization level. This yielded crosslinked samples that were partially crystalline, and where the number of crosslinks could be varied between 1 and 20 crosslinks per 100 anhydroglucose units. The degree of swelling varied regularly with degree of crosslinking, and the molecular weight between crosslinks Mc as derived from swelling data in a good swelling agent compared favorably with Mc derived from chemical analysis.From the heat of gelatinization of the crosslinked starches, as observed in a differential scanning calorimeter, for gelatinization in glycerol, water, and dimethylsulfoxide, a model for the gel state of the crosslinked starch is proposed. It is concluded that the entropy of melting is the determining factor in establishing the temperature of gelatinization.
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  • 35
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    Biopolymers 13 (1974), S. 909-917 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Circular dichroism studies of the interaction of β-cyclodextrin with a series of eight dinucleoside phosphates, and with 3′-AMP are reported. From results with ApU and ApA, it is shown that β-cyclodextrin binding is sensitive to dinucleoside stacking in approximately the same way as optical measures of stacking. Some qualitative uses of β-cyclodextrin binding are suggested, based on the fact that the change in the CD spectrum caused by cyclodextrin binding is unique to each of the dinucleosides studied. Hoffman and Bock have previously suggested the use of β-cyclodextrin as a probe of nucleic acid structure. Their work indicated that only binding to adenosine and inosine would have to be considered. The present paper shows that binding to other bases cannot be neglected, and will impose serious restrictions on the use of β-cyclodextrin as a structural probe.
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  • 36
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    Biopolymers 13 (1974), S. 987-993 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(1,N6-etheno-2-aza-adenylic acid) [poly(2-aza-εA)] was synthesized from 1,N6-etheno-2-aza-adenosine 5′-diphosphate (2-aza-εADP) and Escherichia coli polynucleotide phosphorylase. The values Km = 1.02 mM, V = 1.06 μmol hr-1 enzyme unit-1 were found for the polymerization reaction. In contrast to polyadenylic acid, this novel fluorescent polymer has a random structure in solution. The application of the 2-aza-εADP for localization of polynucleotide phosphorylase was also described.
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  • 37
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    Biopolymers 13 (1974), S. 1011-1022 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of L-methionine oligomers [BOC-(Met)n-OMe] (n = 2-7) and the corresponding diastereomeric di- and tripeptides were synthesized using the mixed anhydride method. Oligomers prepared in this manner were optically pure and were obtained in reasonable yield. Preliminary optical examination of the peptides suggests that secondary structures may begin forming in the pentamer or hexamer in trifluoroethanol. BOC-(Met)4-OMe and BOC-(Met)5-OMe were also synthesized using an insoluble resin containing BOC-L-methionine as the nitrophenol active ester.
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  • 38
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational studies of a series of oligopeptides (from the tripeptide to the octadecapeptide) with the repeating sequence L-norvalyl-glycyl-L-proline and a polytripeptide with this sequence are reported. By means of chiroptical techniques, unordered conformations are found for all oligopeptides in water, trifluoroethanol, and ethylene glycol and for the water-insoluble polymer in trifluoroethanol. In ethylene glycol the polymer assumes a collagen-like structure. Infrared studies indicate that all the oligomers, in contrast to the polymer, are unordered in the solid state.
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  • 39
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    Biopolymers 13 (1974), S. 1109-1116 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Uncharged poly(Nε-methyl-L-lysine) (PMLL) and its isomer, poly(Nδ-ethyl-L-ornithine) (PELO), in alkaline solution (pH ca. 12) undergo a helix-to-β transition upon mild heating at 50°C or higher in a manner similar to that of poly(L-lysine) (PLL). The rate of conversion follows the order: PMLL 〈 PELO 〈 PLL. The helix can be regenerated upon cooling near zero degrees, for instance, after more than 12 hr at 2°C. At concentrations less than 0.02% the β form is intramolecular, but at higher concentrations both intra- and intermolecular β forms are generated. Poly(Nδ-methyl-L-ornithine) (PMLO), an isomer of PLL, behaves like poly(L-ornithine); uncharged PMLO in alkaline solution is partially helical and becomes disordered at elevated temperatures.
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  • 40
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    Biopolymers 13 (1974), S. 1161-1171 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to study the effect of side-chain length on the conformation of polypeptides, conformational changes of various ionic polypeptides with various lengths of side chain, poly-Nε-glutaryl-L-lysine (PGL), poly-Nδ-glutaryl-L-ornithine (PGO), poly-Nε-succinyl-L-lysine (PSL), and poly-Nδ-succinyl-L-ornithine (PGO), were investigated by ORD, potentiometric titration, and dilatometric measurements in aqueous solution. The results of optical rotation and potentiometric titration measurements indicate strongly that the α-helix stability increases in the sequence PSO 〈 PSL ∼ PGO 〈 PGL, which corresponds to increased side-chain length. The volume change associated with the helix-coil transition also increased in the above sequence. This series of polymers seems to be more hydrophobic compared with poly-L-glutamic acid or poly-L-lysine, as suggested from the values of enthalpy and entropy changes for coil-helix transitions.
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  • 41
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    Biopolymers 13 (1974), S. 1195-1203 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational changes of poly-Nε-glutaryl-L-lysine (PGL) and poly-Nε-succinyl-L-lysine (PSL) in various salt solutions were studied by use of ORD and potentiometric titration measurements. The addition of alkali metal salts to the fully ionized PGL or PSL solution caused helix formation. The helical content of the polymers increases in the following sequences: at salt concentration 0-2 M, CsCl 〈 KCl 〈 LiCl 〈 NaCl; and at 2-3 M, LiCl 〈 CsCl 〈 KCl ∼ NaCl. The preferential binding of the solvent components with various alkali metal salts of PGL or PSL was measured in LiCl, NaCl, and KCl solutions by means of equilibrium dialysis and differential refractometry. It was found that with increasing salt concentration, the polymers were preferentially hydrated in NaCl and KCl soultions; however the salt was preferentially bound to the polymers in LiCl solution. Such preferential binding was suggested to be closely related to conformational change. The addition of CaCl2 to polymer solutions led to the stabilization of the helical structure of PGL or PSL.
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  • 42
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    Biopolymers 13 (1974), S. 1261-1267 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Refractive indices of bovine serum albumin solutions in saline and in 2-chloro ethanol are measured for the spectral region 1770-10000 Å by a reflectance method. A procedure for the determination of a dispersion formula for binary mixtures is developed and applied. The electronic polarizability of bovine serum albumin is determined and is found to be almost independent of the solvent and concentration. Hence it follows that the electronic polarizability of bovine serum albumin is almost independent of the molecular environment.
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  • 43
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    Biopolymers 13 (1974) 
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    Keywords: Chemistry ; Polymer and Materials Science
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  • 44
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: The dielectric absorption of poly-DL-phenylalanine and poly-γ-benzyl-L-aspartate (PLAB) was measured in very dilute solutions to determine the type of molecular association and to locate the helix-coil transition. Both polypeptides were present as associated helices in chloroform. The mode of aggregation, which was determined by measuring the dipole moment and the critical frequency, did not depend on the polarity of the side chain but rather on that of the solvent.In both polymers, the dissociation of the aggregates in chloroform was observed on addition of small amounts of dichloroacetic acid; further addition of the acid lead to the helix-coil transition.No second region of dielectric absorption that might be related to the kinetics of the transition was found during the helix-coil transition of PBLA.
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  • 45
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    Topics: Chemistry and Pharmacology
    Notes: Molecular conformation of some polysaccharides in aqueous solution in evidenced by changes in the optical rotation and in the elution pattern of gel filtration. The changes in the specific rotation against that in water are expressed as a molar conformational value [K]D21: -495° for colominic acid in 1.0 N NaOH solution, and -180° for hyaluronate (HA), +85° for corneal keratin sulfate, and +234° for amylose in 8 M urea solution. The gel filtration of amylose and HA dissolved in 8 M urea solution shows elution patterns distinctly different from those dissolved in water. The phenomena are attributable to a molecular conformational transition of polysaccharide molecules in aqueous solution.
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  • 46
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    Topics: Chemistry and Pharmacology
    Notes: A previously described procedure for simultaneous optimization of bond lengths and angles was used to test different models for mannan I. Potential hydrogen bonds and the glycosidic angle were included in the optimization. A conformational model with bifurcated intramolecular hydrogen bonds of the type observed in the methyl cellobioside methanol complex showed the best agreement with available exprerimental data. The coordinates of this model were provided by computer calculations. The available X-ray data, however, were not sufficient for selecting this model; rather, ir data were necessary to furnish the needed information. The different conformational models tested all showed an almost constant virtual bond length O(1)-O(4) of the β-pyranose residue. This was in contrast to the previously obtained results for the α-pyranose residues.
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  • 47
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    Biopolymers 13 (1974), S. 1187-1193 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The longitudinal proton magnetic relaxation times T1 were measured for ferri (met)-and carbonmonoxy-bovine haemoglobin and equine myoglobin in 0.1 M KH2PO4 aqueous solutions near pH 6 at 5°C and 35°C from 1.5- to 60-MHz Larmor frequencies. It is concluded that the correlation time τC for the dipole-dipole interaction of electron and nuclear spins is in fact the electron (ferric) spin relaxation time τS being close to 1.5 × 10-10 sec for both metHb and metMb at 5°C. At 35°C the paramagnetic relaxation rates are not determined solely by the relaxation of protons exchanging from the haem pocket with bulk solvent. Hence, τC at 35°C cannot be calculated from the dispersion data obtained at this temperature. The relevance of this for the determination of interspin distances r is discussed.
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  • 48
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    Biopolymers 13 (1974), S. 1213-1222 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The orientation of naphthalene rings in the side chain of poly-γ-1-naphthylmethyl-L-glutamate (PNLG) in mixed solvents of dichoroethane (DCE) and hexafluoroisopropanol (HFIP) has been studied together with its conformation by infrared, circular dichroism, and fluorescence spectra. The CD pattern of PNLG varies with the solvent composition while it maintains the α-helical conformation. The fluorescence spectra of PNLG in solution show excimer emission of the naphthalene chromophores. The ratio of intensity of the excimer emission to that of the normal fluorescence decreases as the HFIP component in the solvent increases. It is suggested that the naphthalene rings in the side chain of α-helical PNLG are more rigidly orientated in the solvents of higher HFIP ratio.
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  • 49
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    Biopolymers 13 (1974), S. 1269-1290 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The near ultraviolet chiroptical properties of L-cystine conformational isomers are examined on a static, “one-electron” model in which the disulfide moiety is the chromophoric group and the atoms of the L-alanyl fragments are treated as perturbers. The zeroth order chromophoric wave functions are calculated on a semiempirical molecular orbital model in which excited states are constructed in the virtual orbital-configuration interaction approximation. The perturbing environment is represented by point charges located at the atomic centers of the L-alanyl fragments. Chromophore-perturber interactions are expressed as charge-multipole moments with only the charge-dipole and charged-quadrupole terms being retained in the calculations. Vicinal contributions to the rotatory strengths of the five lowest energy disulfide transitions are computed for 30 conformational isomers of the L-cystine dizwitterion. The results provide support for the view that vicinal or peripheral effects can account entirely for the observed near ultraviolet (λ 〉 230 nm) chiroptical properties of L-cystine and its derivatives and that these properties are diagnostic of conformational features external to the disulfide moiety.
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  • 50
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    Topics: Chemistry and Pharmacology
    Notes: The circular dichroic spectrum of poly(Tyr,TyrBr) in trimethylphosphate from 180 to 320 nm is found to be a linear function of composition from 25 to 68% TyrBr, and the spectra of the Tyr and TyrBr components are resolved. For Tyr the resolved spectrum is in agreement with available CD spectra of poly(Tyr). These results are interpreted to mean that the side-chain conformations of Tyr and TyrBr are not affected by the other component, and that for Tyr the conformation is the same as in poly(Tyr). It is also concluded that poly(Tyr,TyrBr) is helical with the same helix sense as poly(Tyr). The restrictions on the side-chain conformations are discussed, and it is suggested that the Tyr and TyrBr side chains are all in the same χ1 region.
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    Biopolymers 13 (1974), S. 1377-1389 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of double-helical nucleic acids was calculated as a function of geometry using the theory of Tinoco and Johnson. This theory does not include contributions of near ultraviolet transitions that are not π → π* in nature. The calculated circular dichroism shows a strong dependence on the distance of base pairs from the helix axis and the tilt of the base pair. Smaller dependences are predicted for the propeller-like twist of a base pair and for variation of the angular increment per base pair. Moderately good agreement between calculated and many experimentally observed spectra could be generated.
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    Biopolymers 13 (1974), S. 1427-1434 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The maximum at 220 nm in the circular dichroism spectrum of native collagen solution changed to a negative value after heat denaturation or collagenase hydrolysis. The enzyme induced rate of CD change at 220 nm was shown to be first order in collagen concentration. The specific rate constant k is actually a combined rate constant kfast and kslow in which the ratio kf/ks is 4.1. The initial rates were linear with respect to enzyme concentration, and the Km was found to be 5.5 × 10-7 M. The rate of ultraviolet hyperchromicity at 220 nm on collagen hydrolysis was determined. The kfast was the same as that obtained by CD. The kf/ks ratio was 4.6. Both methods may be readily used to assay for collagenase activity.
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    Biopolymers 13 (1974), S. 1461-1482 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal and molecular structure of the complex of amylose with dimethyl sulfoxide has been studied by a combination of stereochemical analysis, potential energy, and X-ray diffraction methods. The complex crystallizes in a pseudotetragonal unit cell with a = b = 19.17 Å and c (fiber axis) = 24.39 Å, with two antiparallel chains per unit cell and space group P212121. The amylose chain is a left-handed 61(1.355) helix with three turns per crystallographic repeat. The O(6) rotational position is approximately gt. Dimethyl sulfoxide is located inside the helix with one DMSO molecule for every three glucose residues. An additional four DMSO molecules and eight water molecules each are located in the large interstices between chains, and it is the interaction of these molecules with the helix that results in the pseudotetragonal chain packing. The interstitial DMSO is the source of the previously reported additional layer lines, which are not consistent with the 8.13-Å amylose repeat distance. The final R factor for the layers with amylose contribution to the structure factors was 0.29, while the overall R factor was 0.35. The stereochemical packing analysis provided suitable phasing models for the subsequent X-ray refinement.
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    Biopolymers 13 (1974), S. 1549-1556 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dielectric dispersion of DNA was studied in the frequency range 100 Hz-100 kHz at four different temperatures (6-30°C). The dielectric increment ε0-ε∞ increased with the rise of temperature. The relaxation time, on the other hand, decreased. Both the increase in dielectric increment and the decrease in relaxation time could not be explained on the basis of the counterion polarization theory. Dipole moment was estimated from Kirkwood theory. It was found to decrease systematically with temperature. Even at 0°C there was a dipole moment of 104D.
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    Biopolymers 13 (1974), S. 1573-1605 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dependence of Förster long-range resonance energy transfer efficiency on the orientational freedom of donor D and acceptor A molecules attached to a macromolecular substrate is examined. The usefulness of polarized emission measurements in determining the mutual orientation as well as the degree of orientational freedom of D and A and thereby deriving maximum and minimum values for the D-A separation from the transfer efficieny is demonstrated.
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    Biopolymers 13 (1974), S. 1653-1659 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five human hemoglobins whose genetic relationship to one another involves one set of alleles, hemoglobins CC, SC, SS, AS, and AA, were studied in the deoxygenated form within a McBain gravimetric sorption system at 28°C. Water was used as the adsorbate at relative vapor pressures ranging from 0.11 to 0.39. The results of this study are reported and compared with a similar study on the ferric form of these same five hemoglobins. For both forms of hemoglobin studied, a slight increase was measured in the number of polar sites accessible to H2O vapor for those genotypes in which the substituent in the sixth position from the N terminus of the two β chains had a positively charged side chain, i.e., hemoglobin C. Those samples containing hemoglobin S (less soluble in the deoxy form) show an increased BET monolayer coverage in the deoxy as compared to the ferric form. For each genotype, the deoxygenated form had more polar sites accessible to H2O vapor than its ferric form. This finding is in agreement with an increase in the size of the central cavity as shown by crystallographic analysis.
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  • 57
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    Topics: Chemistry and Pharmacology
    Notes: Thermal denaturation of direct-mixed and reconstituted polylysine-DNA complexes in 2.5 × 10-4 M EDTA, pH 8.0 and various concentrations of NaCl has been studied. For both complexes, increasing ionic strength of the solution raises Tm, the melting temperature of free base pairs. The linear dependence of Tm on log Na+ indicates that the concept of electrostatic shielding on phosphate lattice of an infinitely long pure DNA by Na+ can be applied to short free DNA segments in a nucleoprotein. For a direct-mixed polylysine-DNA complex, the melting temperature of bound base pairs Tm′ remains constant at various ionic strengths. On the other hand, the Tm′ in a reconstituted polylysine-DNA complex is shifted to lower temperature at higher ionic strength. This phenomenon occurs for reconstituted complex with long polylysine of one thousand residues or short polylysine of one hundred residues. It is shown that such a decrease of Tm′ is not due to a reduction of coupling melting between free and bound regions in a complex when the ionic strength is raised. It is also not due to intermolecular or intramolecular change from a reconstituted to a direct-mixed complex. It is suggested that this phenomenon is due to structural change on polylysine-bound regions by ionic strength. It is suggested further that Na+ may replace water molecules and bind polylysine-bound regions in a reconstituted complex. Such a dehydration effect destabilizes these regions and lowers Tm′. This explanation is supported by circular dichroism (CD) results.
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    Topics: Chemistry and Pharmacology
    Notes: Theoretical values are reported for the specific conductivity, charge carrier mobilities, and delocalized free paths in β-polyglycine using the parallel-chain pleated sheet conformation and the all-valence electron energy band structure obtained previously. The mobilities are found to be much larger along the polypeptide backbones than in the direction of the hydrogen bonds. This indicates a mechanism of conduction in which the former path is favored for electronic delocalization. The preexponential factor of the specific conductivity obtained theoretically agrees well with experimental results.
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    Biopolymers 13 (1974), S. 1747-1750 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of a series of L-methionine oligopeptides [BOC-(Met)n-OMe] was examined in trifluoroethanol and hexafluoroacetone sesquihydrate. The results indicate that the trimer through the hexamer exists predominantly in disordered conformations in these solvents. An abrupt change in the CD pattern at the heptamer in trifluoroethanol suggests that L-methionine oligopeptides begin forming helices at this chain length.
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    Biopolymers 13 (1974), S. 1767-1776 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spin-lattice relaxation time (T1) of water adsorbed on collagen fibers was determined at six frequencies and temperatures varying from 25° to -80°C. Care was taken to eliminate the contributions to the signal of protons other than those in the adsorbed water. Quantitative calculations were made on T1 and the results were compared with the experimental data. It is suggested that a maximum of about 0.50-0.55 g water per g collagen forms a hydration layer, which cannot be frozen down to -90°C and exhibits a distribution of motional correlation times. For collagen samples containing a larger quantity of adsorbed water, the additional water molecules behave like ordinary isotropic water, having a single correlation time and a freezing temperature of about -10°C.
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    Biopolymers 13 (1974), S. 1821-1845 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser Raman spectra of the trinucleoside diphoshate ApApA and dinucleoside phosphates ApU, UpA, GpC, CpG, and GpU are reported and discussed. Assignments of conformationally sensitive frequencies are-facilitated by comparison with spectra reported here of poly(rA), poly(rC), and poly(rU) in deuterium oxide solutions. The significant spectral differences between ApU and UpA, and between GpC and CpG, reveal that the sequence isomers have nonidentical conformations in aqueous solution. In UpA at low temperature the bases are stacked and the backbone conformation is similar to that found in ordered polynucleotide structures and RNA. In ApU no base stacking can be detected and the backbone conformation differs from that found in UpA, both in the orientation of phosphodiester linkages and in the internal conformation of ribose. At the conditions employed neither ApU nor UpA exhibits base pairing in aqueous solutions. In both GpC and CpG the bases are stacked and the phosphodiester conformations are similar to those encountered for UpA and RNA. However, major differences between spectra of GpC and CpG indicate that the geometries of stacking and ribosyl conformations are different. In GpC the Raman data favor the formation of hydrogen bonded dimers containing GC pairs. Protonation of C in GpC is sufficient to eliminate the ordered conformation detected by Raman spectroscopy. Despite the ordered backbone conformation evident in GpU, this dinucleoside apparently contains neither stacked nor hydrogen bonded bases at the conditions employed here. The Raman data also confirm the stacking interactions in ApApA, poly(rA), and poly(rC) but suggest that the backbone conformation in poly(rC) differs qualitatively from that found in most ordered polynucleotide structures and is thermally more stable. The present results demonstrate the sensitivity of the Raman technique to sequence-related structural differences in oligonucleotides and provide additional spectra-structure correlations for future conformational studies of RNA by laser Raman spectroscopy.
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    Biopolymers 13 (1974) 
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    Keywords: Chemistry ; Polymer and Materials Science
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  • 63
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    Topics: Chemistry and Pharmacology
    Notes: The 300-MHz proton nmr spectra (between 11 and 14 ppm) of a series of double-stranded deoxy oligonucleotides of known sequence have been recorded in H2O solution. These resonances have been assigned to the G—N1H and T—N3H protons of specific base pairs from an evaluation of the temperature dependence of the ring NH linewidths and from the selective ring NH chemical shift changes on actinomycin-D binding. The deoxy oligonucleotides exist predominantly in the DNA-B conformation as evaluated from antibiotic binding studies. Ring-current calculations have been utilized to evaluate the up-field shifts of the G—N1H and T—N3H protons in Watson-Crick base pairs due to the ring currents from the pyrimidine and purine rings of nearest neighbor base pairs in regular DNA-B- and RNA-A-type helices. The perturbations on these up-field ring-current contributions that arise from twisting and tilting a base pair adjacent to the ring NH under study have been evaluated and found to change the calculated chemical shift by ±0.6 ppm for twist and tilt distortions of 〈30°C in a single adjacent base pair. A knowledge of the experimentally assigned ring NH chemical shifts of specific base pairs in known sequences of double-stranded deoxy oligonucleotides coupled with the ring-current tables for the DNA-B helical structure permit the assignment of 13.6 ± 0.1 ppm and 14.6 ± 0.2 ppm for the G—N1H proton of an isolated GC base pair and the T—N3H proton of an isolated AT base pair, respectively.
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    Chemie in unserer Zeit 8 (1974), S. A4 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
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    Chemie in unserer Zeit 8 (1974), S. 65-71 
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    Keywords: Chemistry ; Chemistry
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    Topics: Chemistry and Pharmacology
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    Chemie in unserer Zeit 8 (1974), S. A40 
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    Keywords: Chemistry ; Chemistry
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    Chemie in unserer Zeit 8 (1974), S. 112-120 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
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    Topics: Chemistry and Pharmacology
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  • 69
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    Chemie in unserer Zeit 8 (1974) 
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    Chemie in unserer Zeit 8 (1974), S. 159-160 
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    Keywords: Chemistry ; Chemistry
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    Chemie in unserer Zeit 8 (1974), S. 192-193 
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    Chemie in unserer Zeit 8 (1974), S. A78 
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    Chemie in unserer Zeit 8 (1974), S. 121-123 
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    Keywords: Chemistry ; Chemistry
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    Topics: Chemistry and Pharmacology
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    Chemie in unserer Zeit 8 (1974), S. 129-134 
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    Keywords: Chemistry ; Chemistry
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    Topics: Chemistry and Pharmacology
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    Chemie in unserer Zeit 8 (1974), S. A66 
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    Chemie in unserer Zeit 8 (1974), S. 177-183 
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    Chemie in unserer Zeit 8 (1974) 
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    Chemie in unserer Zeit 8 (1974), S. 31-32 
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  • 80
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  • 81
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    Biopolymers 13 (1974), S. 29-61 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes the first experimental application of fluorescence correlation spectroscopy, a new method for determining chemical kinetic constants and diffusion coefficients. These quantities are measured by observing the time behaviour of the tiny concentration fluctuations which occur spontaneously in the reaction system even when it is in equilibrium. The equilibrium of the system is not disturbed during the experiment. The diffusion coefficients and chemical rate constants which determine the average time behaviour of these spontaneous fluctuations are the same as those sought by more conventional methods including temperature-jump or other perturbation techniques. The experiment consists essentially in measuring the variation with time of the number of molecules of specified reactants in a defined open volume of solution. The concentration of a reactant is measured by its fluorescence; the sample volume is defined by a focused laser beam which excites the fluorescence. The fluorescent emission fluctuates in proportion with the changes in the number of fluorescent molecules as they diffuse into and out of the sample volume and as they are created or eliminated by the chemical reactions. The number of these reactant molecules must be small to permit detection of the concentration fluctuations. Hence the sample volume is small (10-8 ml) and the concentration of the solutes is low (∼ 10-9 M). We have applied this technique to the study of two prototype systems: the simple example of pure diffusion of a single fluorescent species, rhodamine 6G, and the more interesting but more challenging example of the reaction of macromolecular DNA with the drug ethidium bromide to form a fluorescent complex. The increase of the fluorescence of the ethidium bromide upon formation of the complex permits the observation of the decay of concentration fluctuations via the chemical reaction and consequently the determination of chemical rate constants.
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  • 82
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    Biopolymers 13 (1974), S. 129-138 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The D and L copolymerizations of N-carboxy γ-benzyl glutamate anhydride (NCA) were carried out in a homogeneous solution with various D/L ratios, initiated by either n-butylamine or sodium methoxide, and were followed directly by circular dichroism (CD) to observe the behavior of the secondary structure of growing polymer molecules. In the n-butylamine system, the difference of the helical content between the righthanded and the lefthanded (Δα-helix) gradually increased as the polymerization proceeded, while in the sodium methoxide system, the Δα-helix had a tendency to decrease during the later stages of the polymerization. These results suggest a difference of the power of stereo-selection of monomer antipodes by the growing chain end between these systems, the stereoselectivity by the growing chain end in the sodium methoxide system being higher than that in the n-butylamine system.
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  • 83
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    Biopolymers 13 (1974), S. 169-183 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of Ac-Ala-NHMe, cyclo(-Ala-Ala-), Ac-Ala-OMe, Ac-Ala-Ala-OMe, and Ac-Ala-Ala-Ala-OMe has been measured in water and in aqueous salt solutions as a function of temperature. Only cyclo(-Ala-Ala-) exhibits circular dichroism which is independent of temperature. Each of the linear derivatives of L-alanine exhibits a positive circular dichroism in the range 208-218 nm at 15°C in water. Heating reduces the intensity of the positive circular dichroism, and only Ac-Ala-OMe retains positive circular dichroism at 75°C in water. Isothermal addition of salts produces changes in the circular dichroism of linear derivatives of L-alanine which resemble those seen on heating. The relative effectiveness of the salts tested, at a concentration of 4M, is LiCl ≤ KCl = NaCl 〈 MgCl2 ≤ CaCl2 ≤ NaClO4. The circular dichroism of cyclo(-Ala-Ala-) is also affected by the salts. Extrapolation of the results obtained with Ac-Ala-OMe, Ac-Ala-Ala-OMe, and Ac-Ala-Ala-Ala-OMe to a long polypeptide with a -CH2R side chain in the L-configuration leads to the conclusion that this polypeptide should exhibit a temperature-dependent salt-sensitive positive circular dichroism between 208 and 218 nm when it exists as a statstical coil.
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  • 84
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    Biopolymers 13 (1974), S. 227-235 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The heats of the conformational conversion ΔHc of polyuridylic acid (polyU) in the presence of various cations were determined using a differential scanning microcalorimeter and an isothermal mixing calorimeter. The first method yields a value of ΔHc = 5.2 kcal/mol of base pairs, the second one a value of ΔHc = 6.4 kcal/mol of base pairs. Knowing ΔHc and the maximal slope of the degree of conversion, which was determined from the temperature dependence of the absorbance of polyU solutions at 260 nm, we were able to evaluate the parameter of cooperativity σ. From the relation σ = eΔFstack/RT the stacking free energy ΔFstack could be calculated. Dividing the apparent enthalpy of conversion by the calorimetrically measured enthalpy yields the cooperative length N0 of one helical segment at the midpoint of conversion. The results show that the type of the cation has no influence on the magnitude of ΔHc, whereas the cooperativity of polyU is influenced by the various cations.
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  • 85
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    Biopolymers 13 (1974), S. 861-862 
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    Keywords: Chemistry ; Polymer and Materials Science
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  • 86
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    Biopolymers 13 (1974), S. 903-908 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Clipped autocorrelation functions for the fluctuating intensity of light scattered from dilute solutions of poly-L-lysine in 0.2 M NaBr have been observed over a wide range of time scales down to 1.83 μsec, and over a wide range of pH. Two poly-L-lysine samples of molecular weight 35,000 and 200,000, respectively, were compared to determine the extent of draining of the so-called random-coil configuration. The observed correlation functions were in general very satisfactorily represented by simple translation diffusion of single molecules. At high pH ∼10-10.4, there was evidence of considerable aggregation, but no indication whatsoever of any unusually fast component, as reported recently by Jamieson et al. for poly-L-lysine HBr in the absence of salt.A 30% rise in the diffusion coefficient to a peak at pH 10 parallels the previously reported dip in the intrinsic viscosity, and is interpreted in terms of a more compact structure in that pH region between the coil and helix extremes.
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  • 87
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformation of deoxyribonucleoprotein (DNP) from calf thymus at different stages of deproteinization was studied.The dissociation of the first portion of histone produces no effect on the hydrodynamical and optical behavior of DNP particles. The conformational transition of a macromolecule was observed as soon as the ratio of protein to DNA ≤ 0.9.The effect of ionic strength on the conformation of DNP particles with high protein content was more strongly pronounced than that for DNA. On the contrary, DNP particles depleted of proteins (protein/DNA 〈 0.9) were found to be less sensitive than DNA to the variation of ionic strength. These data imply that the DNP molecules rich in proteins possess a superstructure that is destroyed as the protein/DNA ratio becomes 0.9.The data were analyzed in view of current theories on various model concepts. The most probable model to describe the DNP molecule was chosen by comparing the calculated and experimentally obtained parameters. We believe that DNP is best described as a “compressed coil,” possibly including superhelical regions.
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  • 88
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    Topics: Chemistry and Pharmacology
    Notes: The synthesis of some high-molecular-weight protenoid structures in radiofrequency cold plasma conditions are discussed. The fractionation results of the raw product and the spectrum of free and protenoid-bound amino acids are given. The uv analysis of these compounds is presented.A protein-forming mechanism that might have existed on the primitive earth is proposed.
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  • 89
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    Topics: Chemistry and Pharmacology
    Notes: Double-stranded DNA can be readily adsorbed on mica or directly on carbon coated grids from the surface of solutions containing ethidium bromide, actinomine, or propidium diiodide. The DNA molecules are unfolded, well separated, and show a length distribution similar to molecules prepared by protein monolayer techniques.Since the intercalating dyes tested do not lead to an increased apparent diameter of the nucleic acid the method is useful for the study of nucleic acid-protein complexes. As a model, the binding of E. coli RNA polymerase to phage T7 and T3 DNA was examined under different conditions. The enzyme can easily be identified and its position along the DNA molecule can be mapped.
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  • 90
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization of a series of oligopeptides (from the tripeptide to the octadecapeptide) with the repeating sequence L-norvalyl-glycyl-L-proline and a polytripeptide with this sequence are reported. The oligomers were synthesized step by step using the mixed anhydride method. All the products were chemically and optically pure. The polymer was prepared by the active ester method, using the p-nitrophenyl ester as the polymerizable tripeptide derivative. Good yield of relatively high average molecular-weight polymer was obtained. In the accompanying paper conformational investigations, both in solution and in the solid state, on the oligomers and the polymer are described.
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  • 91
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: Poly(Nδ-carbobenzoxy, Nδ-benzyl-L-ornithine) (PCBLO) was prepared by the standard NCA method. PCBLO was converted into poly(Nδ-benzyl-L-ornithine) (PBLO) through decarbobenzoxylation with hydrogen bromide. The monomer Nδ-benzyl-L-ornithine was synthesized by reacting L-ornithine with benzaldehyde, followed by hydrogenation. The conformation of the two polypeptides was studied by optical rotatory dispersion and circular dichroism. PCBLO forms a right-handed helix in helix-promoting solvents. In mixed solvents of chloroform and dichloroacetic acid (DCA) it undergoes a sharp helix-coil transition at 12% (v/v) DCA at 25°C, as compared with 36% for poly(Nδ-carbobenzoxy-L-ornithine) (PCLO). Like PCLO, the helix-coil transition is “inverse,” that is, high temperature favors the helical form. PBLO is soluble in water at pH below 7 and has a “coiled” conformation. In 88% (v/v) 1-propanol above pH (apparent) 9.6 it is completely helical. In 50% 1-propanol the transition pH (apparent) is about 7.4; this compares with a pHtr of about 10 for poly-L-ornithine in the same solvent.
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  • 92
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    Biopolymers 13 (1974), S. 1141-1160 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The binding of ethidium bromide to DNA has been studied by various optical methods. From fluorescence polarization studies, and film, electric linear dichroism, and circular dichroism spectra, we propose assignments of the absorption bands of the dye, which are discussed in connection with wave-mechanical calculations recently reported.The optical activity induced in the dye absorption bands upon binding to DNA was attributed to various origins depending on the electronic transition considered. The visible absorption band displayed a circular dichroism due to the asymmetry of the binding site and independent of the amount of binding. The transition identified at 378 nm from the circular dichroism and electric dichroism observations was thought to be due to a magnetic-dipole transition. It remained constant with increasing amounts of dye bound. The main ultraviolet band showed circular dichroism characteristics corresponding to exciton interactions between dye molecules bound to neighboring sites.The electric dichroism observed for the strongly bound dye molecules indicated that the phenanthridinium ring of ethidium bromide was probably not perfectly parallel to the DNA base planes. When the amount of dye bound to DNA exceeded the maximum amount compatible with the exclusion of adjacent binding sites, the electric dichroism decreased owing to the appearance of externally bound dye molecules with no contribution to the dichroism.Sonicated DNA was used to study the lengthening of the DNA molecule upon complexation. Although the viscosity of the complexes increased with the amount of binding, the rotational diffusion coefficient measured by the electric birefringence relaxation was not detectably affected. The absence of variation in the electric birefringence with the binding indicated that the DNA base stacking remained unaltered.
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    Biopolymers 13 (1974), S. 1205-1212 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the polymerization of phenylalanine N-carboxyanhydride (NCA) using poly(N-methyl-L-or DL-alanine) diethylamide as initiator, the polymerization rate was L-NCA ≃ D-NCA 〉 DL-NCA. This is a new type of selective polymerization and indicates the incompleteness of earlier investigations to study the asymmetrically selective polymerization without D-NCA. Neither secondary structure nor optical activity of the polymeric initiator is a reason for the selectivity. Hence the cause for the selectivity was sought in the properties of the NCA's in solution. However, the selectivity was not observed in the polymerization initiated by poly(L-phenylalanine) dimethylamide. The importance of the initiator being a secondary amine type was suggested. The experimental results are discussed on the basis of these considerations.
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  • 94
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    Topics: Chemistry and Pharmacology
    Notes: Classical potential energy calculations were performed for the dinucleoside phosphates UpA and GpC. Two widely accessible low-energy regions of conformation space were found for the ω′, ω pair. That of lowest energy contains conformations similar to helical RNA, with ω′ and ω in the vicinity of 300° and 280°, respectively. All five experimental observations of crystalline GpC, two of ApU, and the helical fragment of ApApA fall in this range. The second lowest region has ω′ and ω at about 20° and 80°, respectively, which is in the general region of one experimentally observed crystalline conformer of UpA, and the nonhelical region of ApApA.It is concluded that GpC and ApU, which were crystallized as either sodium or calcium salts, are shielded from each other in the crystal by the water of hydration and are therefore free to adopt their predicted in vacuo minimum energy helical conformations. By contrast, crystalline UpA had only 1/2 water per molecule, and was forced into higher energy conformations in order to maximize intermolecular hydrogen bonding.
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  • 95
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dielectric dispersion measurements on poly-γ-benzyl-L-glutamate (PBLG) in dioxane and dioxane-dichloroacetic acid (DCA) mixtures in the frequency range 200 Hz-2 MHz were made in order to study the structure of molecular aggregates. The structure of aggregates is explained on the basis of the variation of dipole moment and relaxation time with degree of aggregation. PBLG was found to form linear head-to-tail-type aggregates in dioxane. These aggregates gradually reduce in size without loosing their α-helical structure during the process of disaggregation obtained by either adding DCA to the solution in dioxane or by heating. It was confirmed that the addition of 30 wt % DCA completely destroys the aggregation of PBLG in dioxane at 30°C. Thermal disaggregation, however, was not complete even at a temperature approaching the boiling point of the solvent.A reaction scheme for aggregation is proposed and equilibrium constants are calculated at various stages of aggregation. The enthalpy of aggregate formation is found to be -3 kcal/mol. Results of optical rotatory dispersion measurements of the helix-coil transition in this system are also presented.
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  • 96
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Zimm-Bragg parameters s and σ were determined for poly(γ-benzyl L-glutamate) (PBLG) in m-cresol and in dimethylformamide (DMF) from ORD data as a function of molecular weight. It was found that, within the temperature range between 10 and 55°C and on the average, s = 1.61 ± 0.1 and √σ = 0.04 ± 0.01 in m-cresol and s = 1.65 ± 0.05 and √σ = 0.045 ± 0.015 in DMF. The values of s in m-cresol decreased with increasing temperature, while the values of σ in the same solvent increased. This result for s suggests that PBLG in m-cresol will undergo a thermal helix-coil transition of normal type. The parameters in DMF showed no appreciable trend to vary with temperature. Aside from the difference between the two solvents, our results are consistent with existing data for various conformation-dependent properties such as light-scattering radius, intrinsic viscosity, and dipole moment, each indicating that the polypeptide chain has some flexibility in helicogenic solvents.
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  • 97
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    Biopolymers 13 (1974), S. 1391-1403 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism of double-helical nucleic acids was calculated as a function of geometry, including terms involving n → π* transitions. The “nonbonding” n or σ orbitals were of the azine type, delocalized, but concentrated at the nitrogen atoms of the purines and pyrimidines. Dynamic coupling of the magnetic moments of the n → π* transitions with the electric moments of π → π* transitions generated important terms. Mixing of electric dipole character into n → π* transitions by the static electric field perturbation of the molecule is of lesser importance. The largest contributions of n → π* transitions to the circular dichroism of double-helical nucleic acids are comparable in magnitude to the sum of π → π* terms only for geometries where the circular dichroism is weak. Using both n → π* and π → π* contributions one is able to match experimental and calculated circular dichroism spectra for DNA's over a much wider range of conditions than was possible previously.
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  • 98
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    Biopolymers 13 (1974), S. 1435-1445 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Laser Raman spectra are reported for solid films cast from a series of solutions containing mixtures of right- and left-handed α-helices of poly-γ-benzyl-L- and D-glutamate. Procedures were established for producing spectra that were reproducible in position to ±0.3 cm-1 and in relative intensity to a few percent for features of interest. Spectra for the pure L and pure D polymers were identical, as expected. Several small but definite spectral changes appear in the mixtures, reaching a maximum for the racemic 50:50 mixture. The changes are a shift of -1.4 cm-1 in the amide I peak at 1650.5 cm-1; a shift of about -5 cm-1 in the partially resolved amide III peak at 1291 cm-1; a shift of +2.5 cm-1 in the benzyl peak at 3062.5 cm-1; changes in relative intensity of as much as 50% in several regions; and the marked enhancement of several peaks, particularly that at 254 cm-1. These changes are discussed in terms of side-chain interactions in the packing of right- and left-handed helices.
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  • 99
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    Biopolymers 13 (1974), S. 1535-1548 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Self-diffusion coefficient measurements have been applied to the study of Na+, Ca++, and Sr++ in the presence of a linear acidic polysaccharide extracted from cartilage, i.e., chondroitin sulfate. A series of experimental determinations was made with and without supporting electrolytes, and an analysis of experiments involving the separation of the electrostatic interaction terms by an extension of Manning's theory produced results showing the preponderant nature of these electrostatic terms. The specificity of each type of ion or the influence of the pH can be considered merely as higher order corrections with respect to the preceding interactions. Counterion concentration ranges and pH ranges were determined, where either the alkaline-earth counterions become free and hence move with their normal diffusion rate, or these cations are associated with the polyelectrolyte molecule, thus giving a diffusion coefficient similar to that of the macromolecule, or the apparent diffusion coefficients vary between these two extreme diffusion rates as a function of the association equilibria. This variation can be expressed as a function of the linear charge density parameter ξ related to the structure of the polyelectrolyte, the value of which was determined and found in good agreement with published values.
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  • 100
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    Biopolymers 13 (1974), S. 1635-1651 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism (CD) spectrum of polyproline II (PPII) has heretofore been moderately well calculated from exciton theory only at the expense of assuming unreasonable chain conformations and accepting a conservative spectrum in the 180-250-nm region (which is not observed). We have incorporated far uv transitions in the polarizability approximation and, together with the π2π* transition, have calculated the resulting correction to the exciton model. This has been accompanied by a modified assignment of the ππ* transition in PPII, and a simultaneous calculation of the absorption and CD spectra of the α-helix, β structure, PPI, and PPII. We obtain good agreement with the observed CD spectrum of PPII in the 180-250-nm region for acceptable chain conformations. In addition, we predict a negative CD into the far uv, in agreement with recent experimental observations. Our calculations also reproduce features of the far uv CD spectrum of the α-helix, and are in agreement with the CD spectra of the β chain and PPI. The calculated CD of the unordered polypeptide chain is not significantly influenced by far uv contributions, indicating that our previous calculation is valid for such a system. These results demonstrate the importance of incorporating far uv transitions in order to achieve an adequate theoretical explanation of the CD spectra of polypeptides.
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