1,520 research outputs found

    Products Liability and Evidence of Subsequent Repairs

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    Cannabis Àr den mest anvÀnda drogen i vÀrlden och attityderna gentemot den blir allt mer liberala. DÄ mÄnga syntetiskt framstÀllda cannabinoider stÀndigt dyker upp pÄ marknaden visar studier pÄ olika resultat angÄende utbredningen av drogen. Det Àr personer i de yngre Äldrarna som i störst utstrÀckning anvÀnder cannabis. I dagens samhÀlle stÀlls det allt mer krav pÄ unga vuxna, inte minst nÀr det gÀller att skaffa sig en utbildning. Syftet med denna studie var dÀrför att undersöka om det fanns nÄgot samband mellan anvÀndningen av cannabis och upplevelser av studiesituationen bland studenter vid Linköpings universitet.Studiens teoretiska utgÄngspunkt utgjordes av Robert K. Mertons strainteori dÀr fokus lÄg pÄ huruvida studenterna upplevde sig ha förutsÀttningar och medel att uppnÄ sitt mÄl; att klara av en utbildning. Populationen för studien var alla studenter som var registrerade pÄ ett program. En totalundersökning gjordes av de studenter som vÄren 2014 studerade pÄ ett program i termin fyra. Det empiriska materialet samlades in via en onlineenkÀt som besvarades av 1 481 respondenter.Resultatet visade att 36,8 % av respondenterna nÄgon gÄng hade testat cannabis, mÀnnen var signifikant överrepresenterade. De flesta hade testat cannabis första gÄngen dÄ de studerade pÄ gymnasiet. Respondenterna var över lag nöjda med sin studiesituation. Det var inte möjligt att se nÄgot samband mellan anvÀndningen av cannabis och upplevelser av studiesituationen som helhet

    Regulation of non-responsiveness and death in cytotoxic T cells by the agonistic potency of MHC : Peptide ligands

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    CD8+ T lymphocytes are important for immunological control of infections and tumors. The key interaction required to initiate the process of T cell activation is the engagement of the T cell receptor (TCR) with a major histocompatibility complex (MHC) class I/peptide complex on an antigen presenting cell (APC). Depending on the affinity of the interaction between the TCR and MHC class I molecule, different arrays of signaling pathways can be activated in the T cell. Molecular alterations in the peptide bound to the MHC class I can lead to a lower affinity of the MHCTCRinteraction resulting in incomplete or qualitatively different T-cell responses. Altered peptide ligands (APLs) exhibiting such activity are referred to as partial agonists and often occur naturally through genetic instability, which affects T cell epitopes derived from rapidly mutating viruses or tumor-associated cellular antigens. We studied the molecular basis of partial agonism using MHC class I/peptide tetramer complexes. By using tetramers assembled with a fully agonist peptide or its synthetic variant we could study the relationship between tetramer staining, cytokine production and different pathways of activation induced cell death (AICD). We found that positive tetramer staining correlated with at least two different activation programs in CD8+ T lymphocytes: full scale activation associated with Fas-dependent AICD and an incomplete activation followed by Fasindependent AICD. Further, we used raft-disrupting agents to assess the role of lipid rafts in determining the agonistic potency of different peptide ligands. We showed that overall binding of specific tetramers to CTLs was reduced upon raft disruption, although the half-life of tetramer:TCR complexes formed under these conditions was not affected. These findings suggest that different TCR complexes on the surface of CTLs may have different requirements for cholesterol and CTLs may be heterogeneous in their raft structure. In addition we analyzed programs of negative regulation of CD8+ T lymphocytes and the capacity of APLs to activate and modulate such programs. Upon specific triggering CD8+ T-cells become refractory to a secondary stimulus; a condition referred to Activation induced Non-Responsiveness (AINR). We have shown that TCRtriggering results in a novel degradation pathway of Lck, a kinase which plays a critical role in the initiation of T cell activation. Down-regulation of Lck through degradation correlated with AINR in CTLs. By blocking Lck degradation we could prevent the development of AINR. We further investigated how activation of CTLs with APLs affected Lck expression. The capacity of different peptide variants to induce Lck degradation correlated with their agonistic potency. Inefficient recognition of APLs by specific T lymphocytes is believed to contribute to the failure of the immune system to control certain tumor types and progressive viral diseases. To better understand the regulation of APL, activity by immunologic help, we analyzed the capacity of exogenous IL-2 and IL-15 to influence different aspects of activation triggered in CTLs by either fully or partially agonistic peptide ligands. We showed that signals induced by the lymphokines synergize with weak TCR signaling induced by partially agonistic APL, converting many of these peptides from inhibitory to stimulatory ligands. We also demonstrated that IL-2 and IL-15 suppress induction of a death receptor-independent apoptotic program triggered by partially agonistic APL. In conclusion, we have analyzed the molecular basis of partial agonism in CTL recognition of peptide epitopes and characterized molecular changes associated with death and AINR in specific CTLs. We have shown that structural changes in the sequence of CTL peptide epitopes may decrease the affinity of MHC/TCR interactions and generate APLs, which not only trigger incomplete activation programs but also induce and modulate negative regulation programs in CTLs. This APL induced signaling of suppressive nature appears to be more prominent in the absence of immunological help, suggesting that under conditions of immune deregulation APLs may actively suppress CTL responses against infectious agents or tumors

    D i g i t a l i z a t i o n a n d N e w B u y e r B e h a v i o r i s C h a n g i n g B 2 B R e l a t i o n s h i p M a r k e t i n g

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    Problem definition: The increasingly informed customer will lead to an even greater demand for expertise and knowledge of marketers. Firms need to find new ways to utilize the informed customer as a co-creator of value by more proficiently analyzing behavior, both online and offline. An uncertainty lies in to which extent the operational standards of KIBS firms translate to their marketing and sales efforts, or to what degree they are using potential customers to help shape their value propositions. The research question that has been identified is how the relationships seen in knowledgeintensive B2B marketing are affected by the digitalization of society and the change in buyer behavior that is a result of these societal changes. Purpose: The purpose of this thesis will be to identify the effects of digitalization and changing buyer behavior on relationships seen across marketing and sales of knowledge-intensive services in a B2B context. This will lead to a recommendation for the case company’s future direction of its marketing and sales functions. Methodology: The research approach of this master’s thesis has been a combination of a descriptive and !! ! IV! Digitalization and New Buyer Behavior is Changing B2B Relationship Marketing Tobias Olsson Emil Uhlin an explorative study. The descriptive approach intends to describe the overall areas of the problem formulation, while the explorative approach aims to collect as much information as possible regarding these areas. The goal of research has been to put more weight on the explorative approach. The research is approached as a case study focusing on a company that is both B2B and in a sector that includes many interesting angles of the problem. Case company: The choice of Company X as case company for this thesis was rooted in three overall observations. First off, the area of digital marketing is currently seeing increased urgency in B2B. The sector of IT and business consultancy is also interesting. The companies in this sector often have many different ways of working within the same company. The choice of a B2B company is motivated by the fact that the new wave of digital marketing has seen greater advancements in B2C. B2B is historically stronger in much of the relationship marketing basics, like close network relationships. The digital advancements in B2B deviate from those in B2C, and are probably not as standardized. Lastly, an interesting aspect of Company X is that it offers business units on opposite sides of the spectrum in regards to overall digital advancements. Conclusions: Information really is the common denominator for everything that pertains to the power balance of supplier and customer. The authors believe that the presented framework provides a good intersection of assessing relational strength in B2B, the ability to grade strengths and weaknesses as well as opportunities and threats in digitalization, and lastly the level of current buyer insight. The models are secondary and may be modified, but the choice to observe relationships, digitalization and more in-depth buyer behavior should provide a holistic view for similar studies

    Civil Society Elites: A Research Agenda

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    This editorial introduces the thematic issue on ‘civil society elites,’ a topic that has been neglected in elite research as well as civil society studies. It elaborates on the concept of ‘civil society elites’ and explains why this is an important emerging research field. By highlighting different methodological approaches and key findings in the contributions to the thematic issue, this article aims at formulating an agenda for future research in this field

    Cyclic sieving, skew Macdonald polynomials and Schur positivity

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    When λ\lambda is a partition, the specialized non-symmetric Macdonald polynomial Eλ(x;q;0)E_{\lambda}(x;q;0) is symmetric and related to a modified Hall--Littlewood polynomial. We show that whenever all parts of the integer partition λ\lambda is a multiple of nn, the underlying set of fillings exhibit the cyclic sieving phenomenon (CSP) under a cyclic shift of the columns. The corresponding CSP polynomial is given by Eλ(x;q;0)E_{\lambda}(x;q;0). In addition, we prove a refined cyclic sieving phenomenon where the content of the fillings is fixed. This refinement is closely related to an earlier result by B.~Rhoades. We also introduce a skew version of Eλ(x;q;0)E_{\lambda}(x;q;0). We show that these are symmetric and Schur-positive via a variant of the Robinson--Schenstedt--Knuth correspondence and we also describe crystal raising- and lowering operators for the underlying fillings. Moreover, we show that the skew specialized non-symmetric Macdonald polynomials are in some cases vertical-strip LLT polynomials. As a consequence, we get a combinatorial Schur expansion of a new family of LLT polynomials

    Sustainable Filmmaking: Understanding Image as Resource

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    Crystal structure of the Ï” subunit of the proton-translocating ATP synthase from Escherichia coli

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    AbstractBackground: Proton-translocating ATP synthases convert the energy generated from photosynthesis or respiration into ATP. These enzymes, termed F0F1-ATPases, are structurally highly conserved. In Escherichia coli, F0F1-ATPase consists of a membrane portion, F0, made up of three different polypeptides (a, b and c) and an F1 portion comprising five different polypeptides in the stoichiometry α3ÎČ3ÎłÎŽÏ”. The minor subunits Îł, ÎŽ and Ï” are required for the coupling of proton translocation with ATP synthesis; the Ï” subunit is in close contact with the α, ÎČ , Îł and c subunits. The structure of the Ï” subunit provides clues to its essential role in this complex enzyme.Results: The structure of the E. coli F0F1-ATPase Ï” subunit has been solved at 2.3 Å resolution by multiple isomorphous replacement. The structure, comprising residues 2–136 of the polypeptide chain and 14 water molecules, refined to an R value of 0.214 (Rfree = 0.288). The molecule has a novel fold with two domains. The N-terminal domain is a ÎČ sandwich with two five-stranded sheets. The C-terminal domain is formed from two α helices arranged in an antiparallel coiled-coil. A series of alanine residues from each helix form the central contacting residues in the helical domain and can be described as an ‘alanine zipper’. There is an extensive hydrophobic contact region between the two domains providing a stable interface. The individual domains of the crystal structure closely resemble the structures determined in solution by NMR spectroscopy.Conclusions: Sequence alignments of a number of Ï” subunits from diverse sources suggest that the C-terminal domain, which is absent in some species, is not essential for function. In the crystal the N-terminal domains of two Ï” subunits make a close hydrophobic interaction across a crystallographic twofold axis. This region has previously been proposed as the contact surface between the Ï” and Îł subunits in the complete F1-ATPase complex. In the crystal structure, we observe what is apparently a stable interface between the two domains of the Ï” subunit, consistent with the fact that the crystal and solution structures are quite similar despite close crystal packing. This suggests that a gross conformational change in the Ï” subunit, to transmit the effect of proton translocation to the catalytic domain, is unlikely, but cannot be ruled out
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