Influence of hydralazine on interstitial fluid pressure in experimental tumors - a preliminary study

Background. Interstitial fluid pressure (IFP) has been recognised as the most important obstacle in macromolecular drug delivery to solid tumors. Our interest was to reduce differentialy tumor IFP with respect to IFP in surrounding and normal tissues in order to increase drug delivery to tumors aswell to increase tumor blood flow and potentialy tumor tissue oxygenation. In this preliminary study we used hydralazine, a longacting arterial vasodilator. Materials and methods. Measurements of interstitial fluid pressure were performed in vivo on CBA mice bearing SAF tumors using wick-in-needle technigue. Altogether eleven measurements were obtained on different animals with tumors of different size. Results. IFP in tumors after hydralazine administration was significantly lower than initial values in corresponding tumors. On average tumor IFP decreased for 33 % from initial value. On the contrary, no change in IFP in normal tissue was observed after hydralazine administration. Also, after injection of physiological saline instead of hydralazine there was no change in IFP neither in tumors nor in muscle. The results of our preliminary study on the effect of hydralazine on IFP in SAF tumor model is in accordance to previously reported studies. The decrease in tumor IFP was only observed in tumors, but not in muscle and surrounding subcutis. Conclusion. Hydralazine is a vasodilator which is capable of decreasing tumor IFP, reproducibly and with favorably long lasting dynamics

Alexander Dugin and the Theory of a Multipolar World

Aleksander Dugin je politični filozof, sociolog ter politični aktivist in ideolog novoevrazijstva in z njim tesno povezanega projekta snovanja »četrte politične teorije«. Ta naj bi predstavljala politično-filozofski temelj sveta po koncu dobe prevladujočega vpliva Zahoda. Ugotavljamo, da je izhodišče multipolarne teorije zavrnitev a priornega preferiranja značilno modernih političnih konceptov, kakršen naj bi bil tudi nacionalna država. Tej zavrnitvi sledi postuliranje civilizacije kot političnega subjekta, ki odgovarja tako post-moderni globalni stvarnosti kot normativnemu izhodišču kulturnega oziroma civilizacijskega pluralizma. V drugem delu pregledamo nekaj recepcij Duginovega dela in avtorja postavimo v dialog z uveljavljenimi teoretiki na polju sociologije globalizacije in na polju kritične teorije, pregledamo avtorjevo umeščenost in vpliv v ruski javnosti in politiki, v slovenski politični in intelektualni sferi, ob koncu pa podamo nekaj izvirnih kritik in predlogov za nadaljnje raziskovanje. Delo povzema ugotovitev, da opredeljevanje Dugina kot skrajnodesničarskega teoretika in obskurnega ruskega filozofa ni zadostno, kar nas napeljuje na pomen nadaljnjega raziskovanja misli in dela tega kontroverznega misleca.Aleksander Dugin is a political philosopher, sociologist, political activist and ideologue of New Eurasianism and of the closely related project of developing the "fourth political theory", which is supposed to represent the political-philosophical foundations of the world after the end of the era of dominant Western influence. We note that the starting point of the multipolar theory is the rejection of a priori preference for the typical modern political concepts, such as the nation-state. This rejection is followed by the postulation of civilization as a political subject, which corresponds to both the post-modern global reality and to the normative axiom of cultural and civilizational pluralism. In the second part, we examine some of the receptions of Dugin\u27s work and put the author in dialogue with established theorists in the field of sociology of globalization and in the field of critical theory, we examine the author\u27s place and influence in the Russian public and politics, and in the Slovenian political and intellectual sphere. At the end, we give some original criticism and suggestions for further research. We conclude that defining Dugin as a far-right theoretician and an obscure Russian philosopher is insufficient, which leads us to the importance of further research into the thoughts and work of this controversial thinker

Measurement invariance of multilevel variables

Primerjanje med skupinami igra pomembno vlogo v psihologiji in znanosti na splošno. Ko primerjamo skupine med sabo, predpostavljamo, da merski pripomoček meri isti konstrukt v obeh skupinah. Merska invariantnosti preverja psihometrično enakovrednost med skupinami in s tem omogoča primerljivost dosežkov med njimi. Preverjanje merske invariantnosti s potrjevalno faktorsko analizo poteka s pomočjo več gnezdenih modelov. Najprej preverimo konfiguralno invariantnost (enakodimenzionalno strukturo), ki nam omogoča enoten opis testnih dosežkov. Sledi metrična invariantnost (enakost faktorskih uteži), ki omogoča enako interpretacijo faktorjev prek skupin. Ko potrdimo tretji gnezdeni model, ki preverja skalarno invariantnost (enakost presečišč), lahko med sabo neposredno primerjamo skupine udeležencev. V vsakem koraku preverjamo, ali se bolj restriktiven model enako dobro prilega predhodnemu modelu. Prileganje preverjamo s pomočjo indeksov prileganja, kot so CFI, RMSEA, SRMR. Likertove lestvice so v psihologiji pogosto uporabljene za primerjanje med skupinami. Vprašanje, ali je za analizo merske invariantnosti primerneje uporabiti metode za številske ali kategorialne podatke, smo v magistrskem delu preverili s pomočjo simulacijske študije. Preverili smo vedenje indeksov prileganja in p-vrednosti χ2-testa glede na velikost vzorca, število odgovornih kategorij, število postavk, asimetričnost podatkov in simulirano pristranost podatkov. Na podlagi mejnih vrednosti smo preverili, ali so indeksi prileganja pod njihovo mejno vrednostjo za metrično in skalarno invariantnost. Mersko invariantnost vzorca smo potrdili, ko so trije izmed štirih kazalnikov potrdili dobro prileganje. Rezultati, pridobljeni v tej študiji, niso enoznačni. Postopki za analizo merske invariantnosti kategorialnih spremenljivk so bolj priporočljivi v vzorcih s 500 in 1000 udeleženci, medtem ko so postopki za številske podatke enako dobri ali boljši pri vzorcih s sedmimi odgovornimi kategorijami. Indeks prileganja CFI in p-vrednost χ2-testa sta se izkazala kot najprimernejši meri za ocenjevanje razlik med modeli za kategorialne podatke. Študija je pomembna, saj je ena izmed redkih študij, ki je raziskala vpliv mnogih faktorjev na indekse prileganja pri preverjanju merske invariantnosti kategorialnih spremenljivk.Group comparisons is one of the fundamental analytical procedures in psychology and science in general. When comparing groups, it is assumed that the scale, questionnaire, or metric, measures the same construct in both groups. However, due to measurement invariance this is not always the case. It is therefore important to implement measurement invariance when using such measures to assess the psychometric equivalence between groups, enabling comparability between them. Measurement invariance testing using factor analysis involves the use of multiple nested models. This is done by first testing for configural invariance (equidimensional structure), allowing a unified description of test scores. This is followed by testing for metric invariance (equality of factor loadings), enabling the same interpretation of factors across groups. Once the third nested model assessing scalar invariance (equality of intercepts) is tested for, direct comparisons between groups of participants can then be made. Each step of the nested model compares how well the data fits the more restrictive model in comparison to the baseline model. Model fit is assessed using fit indices such as CFI, RMSEA, SRMR. This research explored whether methods for numerical or categorical data are more suitable for analysing measurement invariance by utilising a simulation study. As Likert scales are often used for group comparisons in psychological research, measurement invariance was tested using simulated Likert-type survey responses. Using this data, the behaviour of fit indices and p-values of the χ2 test based on sample size, number of response categories, number of items, data asymmetry, and simulated data bias, were investigated. Using threshold values, it was then explored whether fit indices are below their threshold for metric and scalar invariance. Measurement invariance was confirmed when three out of four indicators showed a good fit. Results from this study therefore indicate that categorical methods are more suitable for analysing measurement invariance in samples with 500 and 1000 participants while numerical methods are similarly or better suited for samples using a seven point Likert scale. CFI and χ2 test p-value proved to be the most appropriate measures for evaluating differences between models for categorical data. This study is one of very few that has explored the impact of several factors on fit indices when assessing measurement invariance of Likert scales

Tipovi motivacije kod volontera, njihove osobine ličnosti i subjektivno blagostanje

Using a person-centered approach, this study sought to identify motivation types of volunteers based on their pattern of motives for volunteering and to compare volunteer types in terms of personality and subjective well-being. A two-step cluster analysis conducted on a sample of 441 volunteers revealed four clusters: integrated high function (high on all motives)integrated low function (low on all motives)self-oriented (primarily motivated to advance own career)other-oriented (primarily motivated to pursue values to help others). The other-oriented and the integrated high function clusters reported the highest levels of extraversion, agreeableness, and openness. While satisfaction with volunteering, subjective well-being, and satisfaction of the needs for relatedness and competence were highest in the integrated high function cluster, the other-oriented cluster exhibited the highest satisfaction of the need for autonomy. Our results complement the dimensional approaches to volunteer motivation and show that optimal motivation is achieved by pursuing multiple motives.Korišćenjem pristupa usmerenog ka osobi, ova studija je imala za cilj da identifikuje tipove motivacije volontera na osnovu šema motiva za volontiranje kao i da poredi tipove volontera u pogledu njihove ličnosti i subjektivnog blagostanja. Klaster analiza iz dva koraka, sprovedena na uzorku od 441 volontera, ukazuje na postojanje četiri klastera: integrisani visoko funkcionalni (sa visokim skorovima na svim motivima)integrisani nisko funkcionalni (sa niskim skorovima na svim motivima)okrenuti ka sebi (eng. self-orientedprimarno motivisani da unaprede sopstvenu karijeru)okrenuti ka drugima (eng. other-orientedprimarno motivisani da teže vrednostima pomaganja drugima). Volonteri koje spadaju u klastere okrenuti ka drugima i integrisani visoko funkcionalni pokazuju najviše nivoe ekstraverzije, saradljivosti i otvorenosti. Sa druge strane, dok su zadovoljstvo volontiranjem, subjektivno blagostanje i zadovoljenje potreba za povezanošću i komptencijom su bili najviši kod integrisanog visoko funkcionalnog klastera, volonteri koji spadaju u klaster okrenuti ka drugima poseduju najviše skorove na zadovoljenju potrebe za autonomijom. Naši rezultati dopunjavaju dimenzionalni pristup motivaciji volontera i pokazuju da se optimalna motivacija može postići putem pokušaja zadovoljenja više motiva