Kanadas Politik des Multikulturalismus vor dem Hintergrund der kanadischen Immigrationsgeschichte

Am 8. Oktober 1971 rief der damalige kanadische Premierminister Pierre Elliott Trudeau die Politik des Multikulturalismus aus, eine Politik deren Ziel die Förderung der kulturellen Vielfalt Kanadas ist. Zu dem Zeitpunkt bestand die Nation aus über 21 Millionen Menschen, darunter viele Immigranten, die zahlreiche Nationalitäten und Kulturen repräsentierten. Knapp hundert Jahre zuvor hatte dieses Bild noch anders ausgesehen. Eine Volkszählung im Jahr 1871 ergab, dass die Bevölkerung des Dominion of Canada zu 60 Prozent aus Briten und zu 30 Prozent aus Franzosen bestand. Diese Entwicklung von einem Zwei-Nationen-Staat hin zu einer multikulturellen Gesellschaft kann durch Kanadas Immigrationsgeschichte erklärt werden. Immigranten waren immer ein wesentlicher Bestandteil Kanadas, weswegen oft von einer Einwanderernation gesprochen wird. Die Untersuchung dieser Masterarbeit konzentriert sich dabei auf die Immigrationspolitik. Es wird aufgezeigt werden wer als Immigrant erwünscht war und wer nicht, und wie man in Krisenzeiten die Einwanderung handhabte. Denn bis zum offiziell anerkannten Multikulturalismus 1971 war es ein langer Weg. Immigration galt als Privileg und folglich ging man bei der Auswahl der Einwanderer sehr selektiv vor. Der Immigrant sollte so “beschaffen” sein, dass er sich leicht in die vor allem anglophone Gesellschaft integrieren konnte. Rassismus und Diskriminierung waren bis in die 1960er Jahre hinein wesentliche Bestandteile der kanadischen Immigrationspolitik.On October 8, 1971, the former Canadian prime minister Pierre Elliott Trudeau proclaimed a policy of multiculturalism, a policy whose aim is to support and foster the cultural variety of Canada. At that time the Canadian nation consisted of more than 21 million people, including many immigrants, who represented various nationalities and cultures. Just a hundred years before the ethnic composition was quite different. A census in 1871 proved that the population of the "Dominion of Canada" was made up to 60 percent of Britons and to 30 percent of French. This development from a Two-Nations-State to a multicultural society can be explained by the immigration history of Canada. Immigration was always an essential component of Canada, this is why it is often referred to as a “nation of immigrants”. The analysis of this master thesis focuses on the immigration policy of Canada. It will be indicated who was welcome as an immigrant and who not, and how Canada dealt with the topic during times of crisis. It was a long way until the policy of multiculturalism was finally approved in 1971. Immigration was considered being a privilege and consequently the immigrants were chosen very carefully. The immigrant had to be the kind that could easily fit into the mainly anglophone society. Racism and discrimination were till the 1960s essential components of the Canadian immigration policy

B-Zell-Rezeptor vermittelte Therapieansätze des primären ZNS-Lymphoms

Das primäre ZNS-Lymphom (PZNSL) zählt zu den hochmalignen B-Zell-Non-Hodgkin-Lymphomen vom diffus großzelligen Typ. Seit dem Ausbruch der AIDS-Epidemie in den 80er-Jahren kam es zu einer Zunahme der Inzidenz dieses Tumors, da eine starke Assoziation zwischen dem primären ZNS-Lymphom und Immunsuppression besteht. Bei immunkompetenten Patienten handelt es sich um einen seltenen Tumor des Lymphsystems, der vorwiegend ab dem 5. Lebensjahrzehnt diagnostiziert wird. Sein Auftreten im ZNS stellt eine Herausforderung für die Behandlung dar. Im Vordergrund der Therapie stehen hirngängige Chemotherapien, vor allem Methotrexat, und die Ganzhirnbestrahlung. Trotz dieser intensiven Therapien, die mit starken Nebenwirkungen behaftet sind, kommt es häufig zu Rezidiven, welche mit einer schlechten Prognose des Gesamtüberlebens einhergehen. Aus diesem Grund ist es wichtig, dass an neuen, gut wirksamen und nebenwirkungsarmen Therapieansätzen geforscht wird. Über den B-Zell-Rezeptor (BZR) erkennen B-Lymphozyten ein für sie spezifisches Antigen, wobei jeder B-Lymphozyt einen in der variablen Region etwas unterschiedlichen BZR besitzt. Da B-Zell-Lymphome von einer entarteten B-Zelle, dem malignen Klon, ausgehen, besitzt jede B-Zelle eines B-Zell-Lymphoms einen identischen BZR, der sie von allen anderen, gesunden B-Lymphozyten unterscheidet. Mit der Entdeckung von BZR-Antigenen maligner Lymphome ergibt sich ein neues, hochspezifisches Therapiekonzept, welches ausschließlich den malignen B-Zell-Klon über dessen B-Zell-Rezeptor angreift. Dieses neue Therapiekonzept wurde BARs („B-cell receptor antigens for reverse targeting“) genannt. Bei circa 67% der Patienten mit PZNSL exprimieren die Lymphomzellen einen BZR, welcher spezifisch das Antigen und BAR Neurabin I bindet. In welchem Format BARs und damit Neurabin I therapeutisch eingesetzt werden können ist unklar. BAR-Bodies integrieren BARs in ein Fab-Antikörper-Format, wobei die variablen Domänen der Schwer- und Leichtkette durch die DNA-Sequenz eines BZR-Antigens, zum Beispiel Neurabin I, ersetzt werden. Ein Neurabin-BAR-Body wurde in dieser Arbeit hergestellt und an das Pseudomonas aeruginosa Exotoxin A gekoppelt, welches nach Internalisierung über den BZR als toxische Wirkkomponente dienen soll. Das BAR-Body-Konstrukt wurde in einem pCES1-Vektor über mehrere Zwischenschritte kloniert und von TGI E. coli-Bakterien exprimiert. Die spezifische Bindung des BAR-Body an Lymphomzellen und deren Internalisierung wurde mittels Durchflusszytometrie ermittelt. Nach Änderung des Fab-Formats in eine reduzierte, nur noch die Schwerkette enthaltende Form, konnte eine spezifische Bindung und Internalisierung nachgewiesen werden. In Zytotoxizitäts-Assays konnte die spezifische Lyse einer, mit einem Neurabin-spezifischen BZR transfizierten, Lymphomzelllinie gezeigt werden. Diese Arbeit beschreibt eine erste potentielle Therapieform des primären ZNS-Lymphoms, welche ausschließlich den malignen Klon trifft, indem die spezifische BZR-Antigen-Interaktion ausgenutzt wird.The primary CNS lymphoma (PCNSL) is an aggressive diffuse large B-cell-Non-Hodgkin-lymphoma. Since the AIDS-epidemic in the 80ies, the incidence of this tumor has increased due to the correlation between primary CNS lymphoma and immunosuppression. In immunocompetent patients, it is a rare tumor of the lymph system, which occurs mainly after the 5th life-decade. Its appearance in the central nervous system poses a challenge for its therapy. Chemotherapy, mostly Methotrexat, and brain radiation are the mainly used therapeutic options. However, they go along with many side effects and even after successful completion of therapy, relapses occur frequently and lead to poor overall-survival. For these reasons new and effective therapies with less side effects are needed urgently. B-lymphocytes recognize antigens specific for them via their B-cell receptor (BCR), each B-lymphocyte having a slightly different BCR in the variable region to cover a wide variety of antigens. As B-cell lymphomas emanate from a degenerate B-cell, the malignant clone, each B-cell of a B-cell lymphoma has an identical BCR that distinguishes it from all other healthy B-lymphocytes. With the discovery of B-cell receptor antigens of malignant lymphomas results a new, highly specific therapy concept, which exclusively attacks the malignant B-cell clone via its B-cell receptor. This new therapy concept was called BARs (“B-cell receptor antigens for reverse targeting”). In about 67% of patients with primary CNS lymphoma, the lymphoma cells express a B-cell receptor on their surface that specifically binds the antigen and BAR Neurabin I. In what format BARs and thus Neurabin I can be used therapeutically is unclear. BAR-Bodies integrate BARs into an antibody Fab-format, replacing the variable domains of the heavy and light chains with the DNA sequence of a B-cell receptor antigen. A Neurabin-BAR-Body was constructed and coupled to the Pseudomonas aeruginosa exotoxin A to serve as a toxic component after internalization via the B-cell receptor of the lymphoma cell. The BAR-Body construct was cloned in a pCES1-vector through intermediate steps and expressed by TGI E. coli bacteria. The specific binding of the BAR-Body to lymphoma cells and their internalization was determined by flow cytometry. After changing the Fab-format to a reduced form containing only the heavy chain, specific binding and internalization could be demonstrated. Cytotoxicity assays revealed the specific lysis of a lymphoma cell line transfected with a Neurabin I specific BZR. This work describes the first potential therapy form of primary CNS lymphoma that exclusively targets the malignant clone by exploiting the specific BZR antigen interaction

MLH1-deficient HCT116 colon tumor cells exhibit resistance to the cytostatic and cytotoxic effect of the poly(A) polymerase inhibitor cordycepin (3'-deoxyadenosine) in vitro

Cordycepin (3'-deoxyadenosine) is an inhibitor of poly(A) polymerase (PAP), an enzyme crucial to mRNA 3'-end processing, which produces the shortening of poly(A) tails, leading to the destabilization of mRNAs. Cordycepin inhibits proliferation and induces apoptosis in tumor cells, indicating its antitumor activity. Defective 3'-end processing is associated with hypersensitivity to UV treatment. We investigated the effects of cordycepin on proliferation and apoptosis in MLH1-deficient and MLH1-proficient HCT116 colon tumor cells. MLH1 is a DNA mismatch repair (MMR) protein involved in the processing of damaged DNA. Cells with defective MMR show resistance to certain anticancer drugs. The results showed that MLH1-deficient HCT116 cells are 2-fold less sensitive to the cytostatic effect of cordycepin, as compared to MLH1-proficient cells. This reduced sensitivity to cordycepin in MLH1-deficient cells was associated with reduced upregulation of the cell cycle inhibitor p21. MLH1-deficient cells also exhibited reduced susceptibility to apoptosis upon treatment with cordycepin, as demonstrated by the reduced PARP-1 cleavage. Our findings showed that MLH1-deficient HCT116 colon tumor cells are resistant to the cytostatic and cytotoxic effect of cordycepin, indicating a possible involvement of MMR in mRNA polyadenylation. The findings also suggest that cordycepin is not suitable to therapeutically encounter tumor cells lacking MLH1 expression

СЛОВО ПРО ПРОФЕСОРА В. В. КРУТІКОВА

The electronic structures of “Ti9-nFe2+nRu18B8” (n = 0, 0.5, 1, 2, 3), in connection to the recently synthesized Ti9-nFe2+nRu18B8 (n = 1, 2), have been investigated and analyzed using LSDA tight-binding calculations to elucidate the distribution of Fe and Ti, to determine the maximum Fe content, and to explore possible magnetic structures to interpret experimental magnetization results. Through a combination of calculations on specific models and using the rigid band approximation, which is validated by the DOS curves for “Ti9-nFe2+nRu18B8” (n = 0, 0.5, 1, 2, 3), mixing of Fe and Ti is anticipated at both the 2b- and 4h-chain sites. The model “Ti8.5Fe2.5Ru18B8” (n = 0.5) revealed that both Brewer-type Ti−Ru interactions as well as ligand field splitting of the Fe 3d orbitals regulated the observed valence electron counts between 220 and 228 electrons/formula unit. Finally, models of magnetic structures were created using “Ti6Fe5Ru18B8” (n = 3). A rigid band analysis of the LSDA DOS curves concluded preferred ferromagnetic ordering at low Fe content (n ≤ 0.75) and ferrimagnetic ordering at higher Fe content (n \u3e 0.75). Ferrimagnetism arises from antiferromagnetic exchange coupling in the scaffold of Fe1-ladder and 4h-chain sites

Torsional selection rules, Raman tensors, and cross sections for degenerate modes of C2H6

16 pages, 12 figures.-- PACS nrs.: 33.20.Tp, 33.15.Mt, 33.70.Fd.We analyze the peculiarities induced by the torsional motion on the Raman spectra of the degenerate vibrational bands of ethane. Selection rules for the Raman transitions between the torsionally split energy levels are derived first in terms of symmetry arguments. Then, their associated intensities are calculated with a model for the torsional dependence of the molecular polarizability. New experimental spectra of the Raman degenerate bands of C2H6, some recorded in jet expansions, are also included and analyzed to show the current state of the problem.This work was supported by the Spanish DGICYT and DGES, research projects PB94-1526 and PB97-1203.Peer reviewe

Шляхи підвищення ефективності використання виробничих ресурсів сільськогосподарських підприємств

Single-phase polycrystalline samples and single crystals of the complex boride phases Ti8Fe3Ru18B8 and Ti7Fe4Ru18B8 have been synthesized by arc melting the elements. The phases were characterized by powder and single-crystal X-ray diffraction as well as energy-dispersive X-ray analysis. They are new substitutional variants of the Zn11Rh18B8 structure type, space group P4/mbm (no. 127). The particularity of their crystal structure lies in the simultaneous presence of dumbbells which form ladders of magnetically active iron atoms along the [001] direction and two additional mixed iron/titanium chains occupying Wyckoff sites 4h and 2b. The ladder substructure is ca. 3.0 Å from the two chains at the 4h, which creates the sequence chain–ladder–chain, establishing a new structural and magnetic motif, the scaffold. The other chain (at 2b) is separated by at least 6.5 Å from this scaffold. According to magnetization measurements, Ti8Fe3Ru18B8 and Ti7Fe4Ru18B8 order ferrimagnetically below 210 and 220 K, respectively, with the latter having much higher magnetic moments than the former. However, the magnetic moment observed for Ti8Fe3Ru18B8 is unexpectedly smaller than the recently reported Ti9Fe2Ru18B8 ferromagnet. The variation of the magnetic moments observed in these new phases can be adequately understood by assuming a ferrimagnetic ordering involving the three different iron sites. Furthermore, the recorded hysteresis loops indicate a semihard magnetic behavior for the two phases. The highest Hc value (28.6 kA/m), measured for Ti7Fe4Ru18B8, lies just at the border of those of hard magnetic materials