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| 72. |
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| 73. |
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| 74. |
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| 75. |
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| 76. |
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| 77. |
- Alonso, Juan M.
(författare)
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Contributions to certain problems in algebraic topology
- 1984
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We consider two problems. The first one is to determine when a fibration is also a (homotopy) cofibration. We use a classic result of T. Ganea to give a complete algebraic solution. When the correspondence between topology and algebra is very close (i.e., when the total space of the fibration is nilpotent} we show that such fibrations can be described quite explicitly and that, in the absence of nilpotency, no such simple characterization exists.The second problem is to find a topological interpretation of the property of having finite quasi-projective dimension (qpd). Groups with this property were introduced by J. Howie and H.R. Schneebeli as a generalization of the Identity Property. We begin by showing that if the group G has qpd G = n, then the relative cohomological dimension of G, rd G, (relative to the maximal finite subgroups of G) is at most n, and we make precise the relationship between qpd G and rd G.By introducing 0-unfree actions we obtain a topological interpretation of the property of having finite rd. We then give the desired interpretation of finite qpd in terms of 0-unfree, periodic actions.Finally, we extend a related result of C.T.C. Wall. Let IG denote the augmentation ideal of G and, if H is a subgroup of G, let JH(G) denote the ideal of ZZG generated by IH. Wall has shown (as sharpened by Dunwoody) that if JH(G) is a direct summand of IG, the pair (G,H) is accessible and Δ= IG/ JH(G) is a ZZG -projective module, then H is a free factor of G. We relax the last condition by demanding instead that the projective dimension of Δ over ZZG be finite.
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| 78. |
- Alpay, Sahin
(författare)
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Turkar i Stockholm : En studie av invandrare, politik och samhälle
- 1980
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present study which is a product of the research project "Political Resocialization of Immigrants (PRI)" carried out at the Political Science Department of the Stockholm University is based primarily on interviews in 1976 with Turkish immigrants in the 18—67 age group domiciled in the Stockholm municipality. The questions this study addresses itself are: — Which pre-migration and migration characteristics of Turkish immigrants in Stockholm are of special importance with respect to their political resocialization? — What are the living conditions of Turks in Stockholm and what are their perceptions and subjective evaluations of these conditions? — In what ways and to what extent do Turks participate in politics in Sweden? — What are the consequences of Turkish immigrants' background characteristics, living conditions and subjective evaluations of these conditions for their political resocialization? The study consists of nine chapters. The first three provide an introduction to this field of research, a discussion of theoretical points of departure, and an account of methods of data-collection. Next two chapters give background information on emigration from Turkey and immigration to Sweden and Stockholm. Chapter six presents data on the Turks' living conditions. They appear to be highly concentrated in the unskilled manual occupations and certain residential areas. Their social contacts are largely limited to relations with fellow countrymen, and they display very poor knowledge of the Swedish language. Chapter seven gives data on the Turks' perceptions and subjective evaluations of their living conditions. Results reveal a relatively high degree of satisfaction primarily with the material welfare they have attained in Sweden, and a rather strong attachment to Turkish culture and identity. Chapter eight discusses the political-cultural background of Turks and provides data on their political participation in Sweden. Findings indicate lower levels of political information, exposure, interest and activity among the Turks as compared to other immigrant groups under study in the PRI-project. The final chapter summarizes the results of the study which show that the political resocialization of Turkish immigrants has so far made little progress. Their political-cultural background characteristics and their living conditions in Stockholm are closely related with their political relearning.
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| 79. |
- Alsberg, Tomas, 1951-
(författare)
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Chemical analysis of complex mixtures with regard to potentially genotoxic organic compounds
- 1984
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes different methods for the extraction, fractionation, and analysis of particle adsorbed organic compounds. The utility of capillary gas chromatography mass spectrometry (GC-MS) for the analysis of polycyclic aromatic compounds (PAC) is demonstrated. Negative ion chemical ionization mass spectrometry (NCI-MS) was used for the selective detection of organic bromides in automobile exhaust extracts. Papers I and II are concerned with the characterization of different sources with respect to their emissions of polynuclear aromatic hydrocarbons (PAH). In Paper III vacuum sublimation is compared to Soxhlet extraction as a means for the extraction of PAC from carbonaceous material.Papers IV, VI, and VII describe a combination of chemical analysis and biological testing. Complex mixtures of PAC obtained from carbon black and from gasoline vehicle exhaust particulates were fractionated into compound classes and tested for genotoxic activity in the Salmonella/microsome test. Fractionation was performed with low pressure liquid chromatography on silica gel, and high-performance liquid chromatography (HPLC) using both normal and reversed phase columns. The genotoxic effects of the different fractions are discussed in relation to the results from the chemical analysis.
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| 80. |
- Alsheikhly, Abdul-Razzak
(författare)
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Virus mediated induction of antibody independent cytotoxicity (VDCC) and enhancement of antibody dependent cytotoxicity (ADCC) in human lymphocytes in vitro
- 1984
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Addition in vitro of small amounts of paramyxoviruses (Mumps or Sendai) to lymphocytes from healthy human donors induces a strong and non-selective cytotoxicity against a variety of target cells (VDCC, virus dependent cellular cytotoxicity). VDCC-like reactions are believed to play a role in vivo in the defense against virus infection and/or the causation of the tissue lesions associated with virus disease. The aim of this study was to investigate the mechanism of VDCC induction, its relationship to other lymphocyte mediated cytotoxic reactions and the nature of the effector cells involved.UV-inactivated virions induce VDCC as efficiently as live virus, indicating that it is not dependent on infection of either lymphocytes or target cells. Removal from the virions of the HN-surface glycoprotein carrying hemagglutination and neuraminidase activities abrogated VDCC. Removal of the F protein (F=fusion) was less efficient. When the lymphocytes were treated with solubilized HN- or F proteins, the HNprotein had full capacity to induce VDCC while the F protein was inactive. The importance of the HN-protein for VDCC was also supported by inhibition experiments with virus specific antibodies. Monoclonal anti-HN antibodies (mumps) inhibited VDCC whereas anti-F, anti-M (membrane) or anti-NP (nucleoprotein) antibodies did not. By using a panel of monoclonals directed to several distinct determinants of the HN-polypeptide, it was shown that at least 3 serologically defined structures of this protein were involved in VDCC induction. These structures appeared to be different from those involved in hemagglutination, hemolysis, neuraminidase activity and infectivity of the virus.When assayed at the level of the effector cell population (51Cr-release), VDCC was reflected by increased target cell lysis. At the effector cell level (single cell conjugate assay), VDCC was the expression of recruitment of both target-binding cells and target killing cells. In short term assays, virus treatment of the lymphocytes did not increase their recycling capacity, confirming that VDCC was primarily due to recruitment. Virus treatment of lymphocytes induces the release of interferon, known to enhance their cytotoxicity. VDCC induction appears to be independent of interferon. However, an activating effect of interferon in later phases of VDCC is not excluded.Cell fractionation experiments and single cell assays in combination with surface marker studies showed that VDCC effector cells were heterogeneous, including both large granular lymphocytes (LGL) and small to medium sized lymphocytes with Tcell characteristics. The cytotoxic effector cells recruited by virus comprised both lymphocytes bearing the LGL-associated HNK-1 antigen and lymphocytes bearing T-cell associated antigens. In absolute numbers, the majority of die effector cells had T-cell characteristics. However, the proportion of the latter differed for target cells of different types, suggesting that the target cells play a role in effector cell selection.VDCC is non-selective and is not MHC restricted, indicating that it is not mediated by specifically cytotoxic T-lymphocytes (CTL). Experiments with cord blood lymphocytes also showed that VDCC was not induced through specific or polyclonal activation by some viral material. VDCC induction is also independent of the participation of anti-target cell antibodies. However, virus treatment of the lymphocytes strongly enhanced their antibody dependent cytotoxicity (ADCC) both against VDCC susceptible tumor target cells and against VDCC resistant erythrocytic target cells. ADCC enhancement was a reflection of effector cell recruitment, primarily involving lymphocytes bearing T-cell markers. It was inhibited by monoclonal antibodies to the HN-protein. Taken together, these experiments showed that virus enhances ADCC by improving the effector cell target cell contacts necessary for cytotoxicity expression. This also results in a significant reduction in the amounts of antitarget cell antibodies required for the triggering of cytotoxicity.
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