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Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę

Single- and multi-photon excited fluorescence from serotonin complexed with B-cyclodextrin

The fluorescence of serotonin on binding with B-cyclodextrin has been studied using both steady-state and time-resolved methods. Steady state fluorescence intensity of serotonin at 340 nm showed ~ 30% increase in intensity on binding with Ka ~ 60 dm3 mol 1 and the fluorescence lifetimes showed a corresponding increase. In contrast, the characteristic green fluorescence (‘hyperluminescence’) of serotonin observed upon multiphoton near-infrared excitation with sub-picosecond pulses was resolved into two lifetime components assigned to free and bound serotonin. The results are of interest in relation to selective imaging and detection of serotonin using the unusual hyperluminescence emission and in respect to recent determinations of serotonin by capillary electrophoresis in the presence of cyclodextrin. The results also suggest that hyperluminescence occurs from multiphoton excitation of a single isolated serotonin molecule

Metabolic activity of tree saps of different origin towards cultured human cells in the light of grade correspondence analysis and multiple regression modeling

Tree saps are nourishing biological media commonly used for beverage and syrup production. Although the nutritional aspect of tree saps is widely acknowledged, the exact relationship between the sap composition, origin, and effect on the metabolic rate of human cells is still elusive. Thus, we collected saps from seven different tree species and conducted composition-activity analysis. Saps from trees of Betulaceae, but not from Salicaceae, Sapindaceae, nor Juglandaceae families, were increasing the metabolic rate of HepG2 cells, as measured using tetrazolium-based assay. Content of glucose, fructose, sucrose, chlorides, nitrates, sulphates, fumarates, malates, and succinates in sap samples varied across different tree species. Grade correspondence analysis clustered trees based on the saps’ chemical footprint indicating its usability in chemotaxonomy. Multiple regression modeling showed that glucose and fumarate present in saps from silver birch (Betula pendula Roth.), black alder (Alnus glutinosa Gaertn.), and European hornbeam (Carpinus betulus L.) are positively affecting the metabolic activity of HepG2 cells

Nanoscale hydroxyl radical generation from multiphoton ionization of tryptophan

Exposure of solutions containing both tryptophan and hydrogen peroxide to a pulsed (~180 fs) laser beam at 750 nm induces luminescence characteristic of 5 hydroxytryptophan. The results indicate that 3-photon excitation of tryptophan results in photoionization within the focal volume of the laser beam. The resulting hydrated electron is scavenged by the hydrogen peroxide to produce the hydroxyl radical. The latter subsequently reacts with tryptophan to form 5-hydroxytryptophan. The involvement of hydroxyl radicals is confirmed by use of ethanol and nitrous oxide as scavengers and their effects on the fluorescence yield in this system. It is postulated that such multiphoton ionization of tryptophanyl residues in cellular proteins may contribute to the photodamage observed during imaging of cells and tissues using multiphoton microscopy

Sur les presupposes et la necessite de recherches relative aux techniques de recherché sociologique

Establishing an adequate research contact with a social reality requires body of preliminary knowledge about it. Such a knowledge should have, one hand, a very general character, i.e., it should concern the nature facts under study (ontological theses, theoretical assumptions, etc.); on p other hand, it should be also very specific and concrete, as it should inform a researcher how the reality under investigation would react to the contact with research techniques when applied to it. In other words, is the question of those aspects or characteristics of reality that are important from the point of view of applicability of available research techniques. These aspects of reality are very often irrelevant to the substantive hypotheses and theories guiding a given research; nevertheless they may predetermine what material will be gathered by means of a chosen research technique, thus influencing substantive results. The knowledge about such meta-substantive or “workshop” traits and aspects of reality under investigation serves a double function, as it constitutes a basis for two kinds of research decisions 1° those concerning the delimitation for research of a segment of the total reality, 2° those concerning the choice or/and the construction of research tools (most often it is a question of techniques designed to evoke some verbal behaviour in collectivities of respondents). A number of examples of concrete survey problems shows that the knowledge of this kind is very heterogeneous (it may concern linguistic problems, demographic structures, various specific regularities in mass as well as in interviewer behavior, etc.). The knowledge of the second kind pertains to the social conditions of applicability of interviewing and questionnaire techniques in various societies, sub-cultures, social milieus, etc. It is necessary to launch a program of empirical research aiming at the systematic cumulation of this kind of knowledge. Such a program is especially imperative when, in a given society, there start up large scale surveys conducted with the help of research techniques developed in the USA and having in the view an international comparison of results. Then, the crucial problem becomes that of the “artificiality” of research situation as well as of the degree of sincerity of answers on the part of respondents. In USA, survey techniques like interviewing and questionnaires constitute a part and parcel of the culture, as they are integrated with well crystallized social roles. Such conditions do not exist as yet in socialist and ‘'third world” countries which “import” American research techniques. In these societies the development of surveys, if they are to bring valid and reliable results, should go hand in hand with the process of acculturation of research techniques used as well as with the intra-national standardization of popular notions and opinions on the character and socio-political functions of sociological researches and their links with the power holders. When starting a research under conditions characterized by a lack of the full acculturation of interviewing and questionnaire techniques, it becomes necessary to choose the most suitable and genuine method of arranging the roles for participants in research situation, i.e. for respondents and interviewers. Such a method should, at the starting point, take into account the existing expectations, experiences, stereotypes and knowledge on the part of the studied population; it should also make allowance for the current popular notion of science and its aims. There are two ways of introducing, into the unprepared social milieu, of interviews or fill-in questionnaires: 1° – a researcher avails himself of the existing, i.e. well known and familiar to his subjects, pattern of social roles, by inserting into it an interview (a “talk”) or fill-in questionnaire (This would be exemplified by a role of a teacher-interviewer who talks with the parents of schoolchildren about the choice of professional career); 2° – the researcher makes his subjects assimilate the new role of informants, i.e. of participants in a scientific research. This requires, however, a longer initiatory action based on the previous field reconnaissance devoted specially to this problem. The answers obtained in a research should be treated as a correlate; of the cristallized pattern of two complementary roles: the one for a researcher (interviewer) and the other for the subject (respondent). Such a role pattern determines least strongly the content of answers expressing only the information level of respondents; it determines more strongly the answers concerning occurrence or non-occurrence of the acts of respondents’ own behavior or of those of in-group members; and finally, it determines to the highest degree the answers being the expression of value judgements and opinions. Opinions and attitudes are functionally connected with a given group situation so that it is normal to express sincerely two contradictory opinions in two corresponding different situations, viz. within two different role patterns. Such an ambivalence, inherent in attitudes and opinions is a phenomenon characteristics of the conditions of rapid social changes, tinder which there coexist two or more different value systems; this is especially the case when there is a sharp division between the private and official sphere of opinion and action, as in socialist countries. The relation between private and official opinions in the same person was investigated in Poland by means of a special technique consisting in the repetition of interviews in two differing social situations. An author of any field research always constructs, more or less consciously, a certain imaginary model of the respondents’ behavior in his research. But the actual behavior always deviates, to some degree, from what such a model presupposes. To assess empirically the scope of contingency between a model and an actual behavior evoked by means of interviewing or questionnaire techniques, it is necessary to obtain systematic; reports prepared by interviewers about the total reactions of respondents to interviewing situations that arise in the field. This would permit to make adjustments in research techniques so as to make them reach model expectations, thus enlarging the scope of validity of such techniques. The existing conceptualizations of situational factors and the sources of bias in interviewing are too schematic because they treat of an interview or a fill-in questionnaire merely from the viewpoint of psychology of communication, at the same time prescinding from the culturally determined social roles in whose framework the research process takes place. The present collection contains the works being an attempt to apply a more comprehensive conceptual scheme to empirical investigations on the factors involved in various research situations

Types of Remunerative Egalitarianism and Meritocratism Distinguished on the Basis of Various Ways of Modification by the Respondents of Actual Salaries of a Director, a Foreman and a Charwoman

Respondents in two representative samples of inhabitants of the city of Łódź in 1977 and 1984 were asked to modify the three demonstrated salaries. Thirteen possible egalitarian and as many meritocratic kinds of modifications were distinguished, the former being those reducing the gap within each of the three pairs of salaries and the latter those enlarging it. Each way of achieving a given modification was given a motivational meaning and appropriate name (e.g.a. “Robin Hood modification”, “equal sharing of poverty”, “jealousy modification”, “enlarging a gap at a generally higher level”, etc.). Empirically ascertained kinds of modifications in two samples were found and their percentage distributions calculated among qualified and unqualified manual workers, white collar workers and pensioners. Diachronic changes in these distributions which occurred between 1977 and 1984 were found and explained by referring to the change in the level of and relations between the three salaries and to the rise of popular radicalism in 1984.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę

The range and direction of bias in a press questionnaire

The present article is a comparative analysis of results of two research works on the popularity of „Głos Szczeciński“ (The Voice of Szczecin) daily paper. One of them was based on questionnaires attached to the paper and returned by riders by mail, and the other on interviews with questionnaires with residents of Szczecin selected at random. The questions put in the two questionnaires were the same: they concerned, among other items, bow often paper was bought, opinions as regards the paper, and preferences as regards various columns and articles. Afterwards, the results obtained in the two investigations were compared in order to ascertain the differences in answers to particular questions and thus to verify following hypotheses; among there who answered the questionnaire a) men, b) people of good education, c) long-established residents of Szczecin, d) the middle-aged, e) regular readers, f) members of political parties, g) individuals with clearly established opinions as regards the content of the daily – will be over-represented. The comparative analysis did indeed confirm most of these hypotheses. No tendentiousness in answering the questionnaire was established as arising from age structure and- the duration of residence in Szczecin. The structure of bias indicated above is explained by the mechanism of the shaping of such phenomena. They are a result of the cumulative effect of objective and -situational factors (the more often the reader purchases the particular daily, the more likely is he to come across the questionnaire), and factors of autoselection (readers having certain social and demographic characteristics who come in contact with the questionnaire are more willing to complete and mail it); the correlation between, the frequency rot reading (or buying) the daily, and similar features account for the very marked over-representation among those who answered the questionnaire, of party, members, men, and people having a higher standard of education. On the basis of a series of similar investigations concerning the direction and range of bias in self-returning questionnaires, it has been possible to establish, a coefficient of tendentiousness in relation, to each of the questions according to the formula: [SEE summary_Gostkowski.pdf] where a = the percentage of answers to the questionnaire, p = the percentage of answers obtained in interviews with the representative sample of readers. Knowing the coefficient Wa, it is possible – on the basis of data from the questionnaire – to establish the percentage of answers to be found in the representative research according to the following formula: [SEE summary_Gostkowski.pdf