Integrable Spin Chains with U(1)^3 symmetry and generalized Lunin-Maldacena backgrounds

We consider the most general three-state spin chain with U(1)^3 symmetry and nearest neighbour interaction. Our model contains as a special case the spin chain describing the holomorphic three scalar sector of the three parameter complex deformation of N=4 SYM, dual to type IIB string theory in the generalized Lunin-Maldacena backgrounds discovered by Frolov. We formulate the coordinate space Bethe ansatz, calculate the S-matrix and determine for which choices of parameters the S-matrix fulfills the Yang-Baxter equations. For these choices of parameters we furthermore write down the R-matrix. We find in total four classes of integrable models. In particular, each already known model of the above type is nothing but one in a family of such models.Comment: 16 pages, 3 figures, references correcte

CXCR2 and CXCL4 regulate survival and self-renewal of hematopoietic stem/progenitor cells

The regulation of hematopoietic stem cell (HSC) survival and self-renewal within the bone marrow (BM) niche is not well understood. We therefore investigated global transcriptomic profiling of normal human hematopoietic stem/progenitor cells, revealing that several chemokine ligands (CXCL1-4, CXCL6, CXCL10, CXCL11, CXCL13) were up-regulated in human quiescent CD34+Hoescht-Pyronin Y- and primitive CD34+38-, as compared to proliferating CD34+Hoechst+Pyronin Y+ and CD34+38+ stem/progenitor cells. This suggested that chemokines may play an important role in the homeostasis of HSCs. In human CD34+ hematopoietic cells, knock-down of CXCL4 or pharmacological inhibition of the chemokine receptor CXCR2, significantly decreased cell viability and colony forming cell (CFC) potential. Studies on Cxcr2-/- mice demonstrated enhanced BM and spleen cellularity, with significantly increased numbers of HSC, hematopoietic progenitor cell (HPC)-1, HPC-2 and Lin-Sca-1+c-Kit+ sub-populations. Cxcr2-/- stem/progenitor cells showed reduced self-renewal capacity as measured in serial transplantation assays. Parallel studies on Cxcl4 demonstrated reduced numbers of CFC in primary and secondary assays following knock-down in murine c-Kit+ cells and Cxcl4-/- mice showed a decrease in HSC and reduced self-renewal capacity after secondary transplantation. These data demonstrate that the CXCR2 network and CXCL4 play a role in the maintenance of normal hematopoietic stem/progenitor cell fates, including survival and self-renewal

Pre-closing formulations in Meeting Talk : A Study of a Cross-functional Team Meeting at Ericsson in Stockholm

Meetings are important arenas where institutional roles and relationships are acted out. Conversation analysis, a data-driven qualitative methodology utilized to study naturally occurring talk-in-interaction, was used in this study to uncover the mechanisms behind meeting talk. In a meeting shared understanding is essential and must be done in an economical manner. One interactional device to reach common agreement are formulations that summarize what has been said or draw out its relevant implication. In this essay, a sub-class of formulations, pre-closing formulations, are in focus. They serve to close the current topic and move on to the next. The aim of this thesis was to find out what kind of interactional devices are used in pre-closure formulations. The findings from the analysis of data, from a cross-functional team meeting at Ericsson in Stockholm, show how a pre-closing formulation followed by silence from the participants is the basis for an agreement. Furthermore the chair can utilize a pre-closing formulation to emphasize the topic of discussion and to influence the sense-making and thus “do” leadership. With a pre-closing formulation the meeting participants can be prepared to be held accountable for the status in a project. However, a pre-closing must not lead to a closing of the topic, the findings show how meeting participants act to continue after the chair’s candidate pre-closing formulation

Visualizing the dynamic interplay between the host and bacterial pathogen : A real-time study of renal infection

The human body is a complex entity capable of handling a variety of pathogenic challenges without developing disease symptoms. Sometimes, however, the pathogens are superior and the host immune system is unable to clear the infection. Alternatively, the host tissue suffers substantial damage during the inflammatory response, which may lead to serious physiological complications. The processes by which this is accomplished are widely dynamic and cannot be understood by studies utilizing simplified model systems containing one cell-type. Until recently the availability of techniques for studying the infection process inside a living organ has been limited. By combining intravital multiphoton microscopy and bacterial genetics we have developed a technique facilitating real-time imaging of the progression of infection in a live animal. Microinjection of GFP+-expressing uropathogenic E. coli (UPEC) into tubules of exteriorized kidneys enabled spatial and temporal control of the experiment. The infection process was followed from the first interaction of bacteria with the epithelial lining, through the dynamic immune response, to the end stage of massive tissue destruction. This dynamic course of events was accomplished within 22 h, a time frame substantially shorter then previously appreciated. For the first time the localized immune cell recruitment was imaged in real-time. Within hours of infection the tubular and vascular integrity was compromized, with subsequent perivascular leakage and ischemic effects. We found UPEC forming multicellular communities on the tubular epithelial lining, indicative of biofilm formation. During later stages of infection, an intermediate filamentous phenotype of the bacteria was observed and UPEC was also found internalized in renal epithelial as well as endothelial cells. This technique also allows a unique opportunity to study subtle and transient in vivo effects of bacterial virulence factors. We found a marked delay in the immune response triggered by a hemolysin (Hly) knock out UPEC strain in comparison to the isogenic wild type strain, even though the level of tissue destruction in the later stage of infection was similar. This is in correlation with the in vitro finding that sub-lytic concentrations of this bacterial exotoxin induces a pro-inflammatory response in renal epithelial cells, while high doses are lytic to both erythrocytes and nucleated cells. Hly is known to tightly interact with the bacterial outer membrane component lipopolysacharide (LPS) and we investigated whether this interaction is important for the dual concentration-dependent activities of Hly. Our findings show that LPS is essential for the pro-inflammatory signaling triggered by Hly, but not for the lytic activity. The Hly-LPS complex is targeted to lipid rafts in the host membrane through interaction with LBP and CD14, which represents a novel molecular mechanism for toxin delivery in bacterial pathogenesis. The visualization techniques presented in this thesis can be applied to study the tissue response to a variety of bacterial pathogens. A detailed understanding of how the host responds to invading microbial pathogens and the in vivo importance of bacterial virulence factors is crucial for the development of new approaches to combat microbial infections

Livsviktigt arbete bakom en skärm : En studie i socialt arbete om ideella tjej- och transjourares syn på sin roll som stödjare

The purpose of this study was to investigate how volunteers at young women´s and transgender empowerment centers in Sweden reason about their role and their discretion in order to better understand and problematize the responsibility of conducting social work without necessarily holding an education as a social worker. The study focuses on their supportive role in online chats with young callers who make contact in need of more or less urgent support. The method chosen was qualitative semi-structured interviews with six volunteers from five different young women’s or young women’s and transgender empowerment centers. For the analysis theoretical perspectives on discretion were used. A major finding was that the interviewees experience the anonymity of the young callers as both a positive and a negative aspect of the set-up of their task as supporters, behind a screen. One expressed negative aspect was that the anonymity limits both the reach and the kind of support they are able to provide, which therefore also limits their discretion. The volunteers described themselves to be using knowledge that is provided to them by the empowerment centers, continuously. The skill to be a good supporter is also spoken of as being achieved within the team while working, through helping each other out with difficult online chats. Sometimes they also use their own personal experiences. Instead of talking about their role as professional the volunteers described themselves as friends or sisters. Because this is the way they use their role, and – somewhat paradoxically - due to their limited discretion, the online chat becomes a safe place for young people in need of support. The volunteers all emphasises this ’unprofessional’ role as many times vital to the callers

Remissen som kommunikationsmedel mellan remittent och röntgenavdelningen : En litteraturstudie

Radiology is an accepted part of medical practice and is justified if the radiation dose is as low as reasonably achievable while it ensures desired diagnostic value. The unnecessary utilization of diagnostic modalities is often caused by reasons which could be eliminated with improved and more informative x-ray referrals. The x-ray referral should justify the required examination and a good anamnesis must be included, with important clinical data and a current request, to optimize the examination. Despite this the information in the referral is often insufficient, inaccurate and misleading. The overall aim of this literature study was to describe the deficiencies in the incoming data in X-ray referrals. According to the overall aim of the study two questions at issue where formulated and scientific support for these where searched. In this study 16 scientific articles are included. The articles in the analysis indicate a high frequency of referrals lacking justification in response to the required examination, and the occurrence of unnecessary and suboptimal diagnostic examinations due to lack of information in the referrals. Unspecified referral, poorly articulated inquires and incorrect choice of method complicated the diagnostic procedures and slowed down the workflow in the Department of radiology. To achieve improvement of the referrals education is required along with implementation of guidelines in the referents’ work setting.Validerat; 20120208 (anonymous

Att gå i svensk skola med invandrarbakgrund - en studie om kulturella möten

Arbetet handlar om de kulturmöten som en elev med invandrarbakgrund kan uppleva i mötet med en svensk skola. I uppsatsen presenteras historik och fakta om invandrarbarn. De frågor vi har valt att undersöka är om skolmaten anpassas till elevernas kulturella bakgrund och hur man förhåller sig till olika högtider i skolan. Problemen som uppmärksammas i litteraturen stämmer inte med den verklighet vi har stött på genom de intervjuer vi gjort. Exempel på detta är skolan, maten och högtiderna. För att få svar på undersökningen frågor har en kvalitativ intervjuform använts. Vi har vänt oss till elever i olika åldrar och på olika skolor. Resultaten visar olikheter mellan litteratur och intervjuer. De elever vi intervjuat med anser sig inte ha några problem med vare sig skolan, maten eller högtiderna. Man får stöd och hjälp i form av förberedelseklasser, maten anpassas och man firar oftast både sina egna och våra högtider

Extracellular Optogenetics at the Interface of Synthetic Biology and Materials Science.

We review fundamental mechanisms and applications of OptoGels: hydrogels with light-programmable properties endowed by photoswitchable proteins (optoproteins) found in nature. Light, as the primary source of energy on earth, has driven evolution to develop highly-tuned functionalities, such as phototropism and circadian entrainment. These functions are mediated through a growing family of optoproteins that respond to the entire visible spectrum ranging from ultraviolet to infrared by changing their structure to transmit signals inside of cells. In a recent series of articles, engineers and biochemists have incorporated optoproteins into a variety of extracellular systems, endowing them with photocontrollability. While other routes exist for dynamically controlling material properties, light-sensitive proteins have several distinct advantages, including precise spatiotemporal control, reversibility, substrate selectivity, as well as biodegradability and biocompatibility. Available conjugation chemistries endow OptoGels with a combinatorially large design space determined by the set of optoproteins and polymer networks. These combinations result in a variety of tunable material properties. Despite their potential, relatively little of the OptoGel design space has been explored. Here, we aim to summarize innovations in this emerging field and highlight potential future applications of these next generation materials. OptoGels show great promise in applications ranging from mechanobiology, to 3D cell and organoid engineering, and programmable cell eluting materials

Hiv i Sverige : kunskaper, attityder och beteenden hos allmänheten 1987-2011

Syftet med denna rapport är att undersöka hur allmänhetens attityder, kunskaper och beteenden i fråga om hiv har förändrats under perioden 1987–2011. Den baseras på åtta enkätundersökningar, vardera riktade till ett slumpmässigt urval av 4 000–6 000 individer ur den svenska befolkningen