Evaluating Search Systems through Field Codes and Classifications: The Case of the First Published Swedish Nursing Study

The aim of the study was to assess and compare established search systems and approaches by using the search goal of identifying the first (as in oldest) nursing-related document, with reference to the first Swedish-affiliated document, in Scopus, Web of Science, and PubMed (Medline). In doing so, the objective was to provide concrete examples and illustrate how search systems and field code searches versus classification-based searches differ. The Scopus database, Web of Science database aggregator, and the PubMed (Medline) search engine were used for evaluations. Two different search strategies were compared in each database: one guided by field codes (i.e., text-based), and one guided by pre-existing categorizations within database infrastructures. Findings highlight several factors that are important to consider when formulating and executing a search strategy. The findings illustrate important aspects of search systems and search approaches, namely the publication year, delimitations related to a country or region, and features related to a subject or research area. The findings also highlight the importance of prioritizing between different ideals in retrieval. For example, is it more important to reach the oldest records (publication year), to identify as many records as possible (exhaustiveness), or to make sure they are as subject-relevant as possible (e.g., in terms of authors belonging to the same field)? Secondly, researchers using bibliometric methods to analyze research literature should be more transparent when reporting searches, as different search systems and search approaches yield varied numbers and quality of records. While most bibliometric researchers strive to combine different approaches, this is not always made clear in reporting.Comment: 12 pages in total (including first page and pages containing bibliography). 4 table

The secretome of myofibroblasts and its significance in gastric cancer

The microenvironment is important in regulating the behaviour of cancer cells. Myofibroblasts are a key stromal cell type with important roles in defining microenvironments in both health and disease by secreting proteins including growth factors, proteases andextracellular matrix (ECM) components. In the case of gastric cancer, the myofibroblast population is significantly expanded compared with the adjacent non-cancer tissue, and with healthy gastric tissue. It has been shown in other cancers that cancer-associated myofibroblasts (CAMs) can promote tumour development and progression via secreted proteins such as hepatocyte growth factor (HGF) and stromal cell-derived factor 1 (SDF-I). In the stomach it has been shown that changes in the signalling between myofibroblasts and the adjacent epithelial cells are important in mediating the effects of the gastric pathogen Helicobacter pylori. Proteomic studies showed that increased secretion of matrix metalloproteinase 7 (MMP7) by the epithelial cells during H pylori infection causes cleavage of insulinlike growth factor binding protein-5 (IGFBP-5) in the myofibroblast secretome, resulting in increased bioavailability of IGF-II. This thesis is the first comprehensive study of gastric myofibroblast secretomes. The aim of this thesis was to define the differences between gastric CAMs and their adjacent non-cancer tissue myofibroblast (ANM) counterparts. This study made use of the unique availability in the group of cultures of myofibroblasts derived from human gastric carcinoma samples and adjacent noncancer tissue. In vitro assays revealed that CAMs were more migratory than ANMs, both in response to IGF-II and when unstimulated. Comparison of CAM and ANM transcriptomes by gene expression array revealed significant differences, particularly in genes related to transforming growth factor beta (TGF~) signalling. Myofibroblast conditioned media was used to stimulate AGS cells, a gastric cancer cell line. This revealed that CAM conditioned media induced greater AGS migration and invasion than ANM conditioned media. Gene expression array analysis of the stimulated AGS cells showed that these phenotypic differences were accompanied by significant changes in gene expression. Again, many of the differences were in genes involved in TGFp signalling. These experiments suggested that the most important differences between CAMs and ANMs were in their secretomes. Quantitative proteomic analysis of the myofibroblast secretomes and proteomes using the isobaric tagging for relative and absolute quantitation (iTRAQ) system revealed that a large proportion of the secreted proteins were differentially abundant in CAM media compared with ANM media. Most of these proteins, including ECM components and protease inhibitors, were less abundant in the CAM media. Only a small number of proteins, including proteases, were more abundant in CAM media than in ANM media. These results suggested a higher level of proteolytic activity in the CAM secretome. Analysis of the secretome of one CAM and ANM pair by combined fractional diagonal chromatography (COFRADIC) revealed greater proteolytic processing of several proteins in CAM media compared with ANM media. These included proteins with roles in TGFp signalling, ECM components and proteases. One protein which was often identified in proteomic experiments as being less abundant in CAM media than ANM media was TGFp ig-h3. This is a TGFp-induced extracellular protein with a known role in cellular adhesion. It was shown by Western blotting that in several cases Pig-h3 was either less abundant or more degraded in CAM media than ANM media, With proteomic and Western blot data taken together there was evidence for either reduced abundance or increased degradation of ~ig-h3 in 9 out of 11 CAMs compared with their matching ANMs. In vitro assays revealed that ~ig-h3 inhibited AGS cell migration in response to myofibroblast conditioned media. It was also shown that ~ig-h3 could be cleaved by plasmin, and that inhibiting urokinase plasminogen activator (uPA), which can convert plasminogen into active plasmin, also inhibited AGS cell migration in response to myofibroblast conditioned media. Together these data show that there are significant differences between gastric CAMs and ANMs. Many of these differences involve genes and proteins with known roles in TGF~ signalling, and the key differences are in the secretome. These differences, including a higher level of proteolytic activity in CAM media, result in a more migratory response in AGS cells. This suggests that CAMs could be important in defining a microenvironment in cancer which might promote a more aggressive cancer phenotype

Weight Status and BMI-Related Traits in Adolescent Friendship Groups and Role of Sociodemographic Factors : The European IDEFICS/I.Family Cohort

Background: During adolescence, health behaviors and weight status are increasingly influenced by friendship and peer networks. This paper examines resemblances in weight-related characteristics and how they differ by sociodemographic factors. Methods: Over 3,000 friendships were reported by 1,603 adolescents, aged 11-16 years, who participated in the school-based I.Family study in 6 European countries. Each "source child" named 1-10 friends for whom standardized weight-related traits were available in the same survey. The mean value of the friends' traits weighted by time spent together was calculated, and related to the source child's trait. Country, age and sex of the source child, parental education, and immigrant background were considered for confounding and moderation. Results: Source children's z-scores of body fat percent and BMI were positively associated with their friends' characteristics, in particular if they had highly educated parents. Positive associations were also found regarding the frequency of fast-food consumption, impulsivity, screen time, preference for sugar-sweetened foods, and hours spent in sports clubs, in increasing order of effect size. Additionally, correlations were observed between friends' cognitive and school functioning and being bullied. No associations were seen for a preference for high-fat foods, weight concerns, and health-related quality of life. Finally, parental education and immigrant background were associated between friends in all countries except Sweden, where no associations were observed. Conclusion: Adolescent friends shared a number of weight-related characteristics. For weight measures per se, positive associations with friends' characteristics were only observed in adolescents with high parental education. Associations regarding energy-balance behaviors and indicators of school-related well-being did not differ by parental education. Parental education and immigrant background correlated positively in friends in most countries showing that social aggregation is already occurring in adolescence. The wide spectrum of friendship associations in weight-related traits and behaviors suggests that health promotion initiatives in adolescents should be directed towards peer groups in both school-related and leisure-time environments. ISRCTN Registry: Pan-European IDEFICS/I.Family children cohort (ID ISRCTN62310987; https://doi.org/10.1186/ISRCTN62310987).Peer reviewe

The Quantity of Intracluster Light: Comparing Theoretical and Observational Measurement Techniques Using Simulated Clusters

Using a suite of N-body simulations of galaxy clusters specifically tailored to study the intracluster light (ICL) component, we measure the quantity of ICL using a number of different methods previously employed in the literature for both observational and simulation data sets. By measuring the ICL of the clusters using multiple techniques, we identify systematic differences in how each detection method identifies the ICL. We find that techniques which define the ICL solely based on the current position of the cluster luminosity, such as a surface brightness or local density threshold, tend to find less ICL than methods utilizing time or velocity information, including stellar particles' density history or binding energy. The range of ICL fractions (the fraction of the clusters' total luminosity found in the ICL component) we measure at z=0 across all our clusters using any definition span the range from 9-36%, and even within a single cluster different methods can change the measured ICL fraction by up to a factor of two. Separating the cluster's central galaxy from the surrounding ICL component is a challenge for all ICL techniques, and because the ICL is centrally concentrated within the cluster, the differences in the measured ICL quantity between techniques are largely a consequence of this central galaxy/ICL separation. We thoroughly explore the free parameters involved with each measurement method, and find that adjusting these parameters can change the measured ICL fraction by up to a factor of two. While for all definitions the quantity of ICL tends to increase with time, the ICL fraction does not grow at a uniform rate, nor even monotonically under some definitions. Thus, the ICL can be used as a rough indicator of dynamical age, where more dynamically advanced clusters will on average have higher ICL fractions.Comment: 18 pages, 11 figues. Accepted for publication in Ap

White Dwarf Kinematics vs Mass

We have investigated the relationship between the kinematics and mass of young (<3x10^8 years) white dwarfs using proper motions. Our sample is taken from the colour selected catalogues of SDSS (Eisenstein et al. 2006) and the Palomar-Green Survey (Liebert, Bergeron & Holberg 2005), both of which have spectroscopic temperature and gravity determinations. We find that the dispersion decreases with increasing white dwarf mass. This can be explained as a result of less scattering by objects in the Galactic disk during the shorter lifetime of their more massive progenitors. A direct result of this is that white dwarfs with high mass have a reduced scale height, and hence their local density is enhanced over their less massive counterparts. In addition, we have investigated whether the kinematics of the highest mass white dwarfs (>0.95Msun) are consistent with the expected relative contributions of single star evolution and mergers. We find that the kinematics are consistent with the majority of high-mass white dwarfs being formed through single star evolution.Comment: 14 pages, 15 figures. Accepted by MNRA

Mapping proteolytic processing in the secretome of gastric cancer-associated myofibroblasts reveals activation of MMP-1, MMP-2, and MMP-3

Cancer progression involves changes in extracellular proteolysis, but the contribution of stromal cell secretomes to the cancer degradome remains uncertain. We have now defined the secretome of a. specific stromal cell type, the rnyofibroblast, in gastric cancer and its modification by proteolysis. SILAC labeling and COFRADIC isolation of methionine containing peptides allowed us to quantify differences in gastric cancer-derived myofibroblasts compared with myofibroblasts from adjacent tissue, revealing increased abundance of several proteases in cancer myofibroblasts including matrix metalloproteinases (MMP)-1 and -3. Moreover, N-terminal COFRADIC analysis identified cancer-restricted proteolytic cleavages, including liberation of the active forms of MMP-1, -2, and -3 from their inactive precursors. In vivo imaging confirmed increased MMP activity when gastric cancer cells were xenografted in mice together with gastric cancer myofibroblasts. Western blot and enzyme activity assays confirmed increased MMP-1, -2, and -3 activity in cancer myofibroblasts, and cancer cell migration assays indicated stimulation by MMP-1, -2, and -3 in cancer-associated rnyofibroblast media. Thus, cancer-derived myofibroblasts differ from their normal counterparts by increased production and activation of MMP-1, -2, and -3, and this may contribute to the remodelling of the cancer cell microenvironment

UV Star Formation Rates in the Local Universe

We measure star formation rates of ~50,000 optically-selected galaxies in the local universe (z~0.1), spanning a range from gas-rich dwarfs to massive ellipticals. We obtain dust-corrected SFRs by fitting the GALEX (UV) and SDSS (optical) photometry to a library of population synthesis models that include dust attenuation. For star-forming galaxies, our UV-based SFRs compare remarkably well with those derived from SDSS H alpha. Deviations from perfect agreement between these two methods are due to differences in the dust attenuation estimates. In contrast to H alpha, UV provides reliable SFRs for galaxies with weak or no H alpha emission, and where H alpha is contaminated with an emission from an AGN. We use full-SED SFRs to calibrate a simple prescription that uses GALEX UV magnitudes to produce good SFRs for normal star-forming galaxies. The specific SFR is considered as a function of stellar mass for (1) star-forming galaxies with no AGN, (2) those hosting an AGN, and for (3) galaxies without H alpha emission. We find that the three have distinct star formation histories, with AGN lying intermediate between the star-forming and the quiescent galaxies. Normal star forming galaxies (without an AGN) lie on a relatively narrow linear sequence. Remarkably, galaxies hosting a strong AGN appear to represent the massive continuation of this sequence. Weak AGN, while also massive, have lower SFR, sometimes extending to the realm of quiescent galaxies. We propose an evolutionary sequence for massive galaxies that smoothly connects normal star-forming galaxies to quiescent (red sequence) galaxies via strong and weak AGN. We confirm that some galaxies with no H alpha emission show signs of SF in the UV. We derive a UV-based cosmic SFR density at z=0.1 with smaller total error than previous measurements (abridged).Comment: Accepted for publication in ApJ (Special GALEX Supplement issue - Dec 2007). v2: Typo in Eq. 2 correcte

Catalogs of Hot White Dwarfs in the Milky Way from GALEX's Ultraviolet Sky Surveys. Constraining Stellar Evolution

We present comprehensive catalogs of hot star candidates in the Milky Way, selected from GALEX far-UV (FUV, 1344-1786 AA) and near-UV (NUV, 1771-2831 AA) imaging. The FUV and NUV photometry allows us to extract the hottest stellar objects, in particular hot white dwarfs (WD), which are elusive at other wavelengths because of their high temperatures and faint optical luminosities. We generated catalogs of UV sources from two GALEX's surveys: AIS (All-Sky Imaging Survey, depth ABmag~19.9/20.8 in FUV/NUV) and MIS (Medium-depth Imaging Survey, depth ~22.6/22.7mag). The two catalogs (from GALEX fifth data release) contain 65.3/12.6 million (AIS/MIS) unique UV sources with error(NUV)<0.5mag, over 21,435/1,579 square degrees. We also constructed subcatalogs of the UV sources with matched optical photometry from SDSS (7th data release): these contain 0.6/0.9million (AIS/MIS) sources with errors <0.3mag in both FUV and NUV, excluding sources with multiple optical counterparts, over an area of 7,325/1,103 square degrees. All catalogs are available online. We then selected 28,319(AIS)/9,028(MIS) matched sources with FUV-NUV<-0.13; this color cut corresponds to stellar Teff hotter than ~18,000 K. An additional color cut of NUV-r>0.1 isolates binaries with largely differing Teff's, and some intruding QSOs. Available spectroscopy for a subsample indicates that hot-star candidates with NUV-r<0.1 have negligible contamination by non-stellar objects. We discuss the distribution of sources in the catalogs, and the effects of error and color cuts on the samples. The density of hot-star candidates increases from high to low Galactic latitudes, but drops on the MW plane due to dust extinction. Our hot-star counts at all latitudes are better matched by Milky Way models computed with an initial-final mass relation that favours lower final masses. (ABRIDGED)Comment: To appear in MNRAS. Better printed in colou

Exploring the promotion of synthons of choice: halogen bonding in molecular lanthanide complexes characterized via X-ray diffraction, luminescence spectroscopy, and magnetic measurements

Promotion of a synthon of choice for the non-covalent assembly of lanthanide tectons represents both a noteworthy challenge and opportunity within LnIII hybrid materials. We have developed a system, wherein some control can be exercised over supramolecular assembly and, as part of continued efforts to improve this process we have generated a family of ten new lanthanide (Ln = Sm3+ – Lu3+) 2,4,6-trichlorobenzoic acid-1,10-phenanthroline molecular complexes. Delineation of criteria for promoting assembly via halogen based interactions was introduced previously and is refined herein based on the characterization of complexes 1–10 via single-crystal X-ray diffraction. Direct comparison of means of supramolecular assembly for 1–10 with isostructural Ln-p-chlorobenzoic acid-1,10-phenanthroline analogues verifies that increasing the number of halogen atoms at the periphery of a tecton is one route that increases the frequency of halogen bonding interactions. Additionally, solid-state visible and near-IR photoluminescence and luminescent lifetime data were collected for complexes 1 (Sm3+), 2 (Eu3+), 4 (Tb3+), 5 (Dy3+), 6 (Ho3+), 7 (Er3+), and 9 (Yb3+) and characteristic emission was observed for all complexes except 6. Further, direct current magnetic susceptibility measurements were carried out for complexes 5 (Dy3+) and 7 (Er3+), and two slow magnetic relaxation processes were characterized using alternating current magnetic susceptibility measurements for 5

Weight Status and BMI-related traits in adolescent friendship groups and role of sociodemographic factors : the European IDEFICS/I.Family Cohort

Background: During adolescence, health behaviors and weight status are increasingly influenced by friendship and peer networks. This paper examines resemblances in weight-related characteristics and how they differ by sociodemographic factors. Methods: Over 3,000 friendships were reported by 1,603 adolescents, aged 11-16 years, who participated in the school-based I.Family study in 6 European countries. Each "source child" named 1-10 friends for whom standardized weight-related traits were available in the same survey. The mean value of the friends' traits weighted by time spent together was calculated, and related to the source child's trait. Country, age and sex of the source child, parental education, and immigrant background were considered for confounding and moderation. Results: Source children's z-scores of body fat percent and BMI were positively associated with their friends' characteristics, in particular if they had highly educated parents. Positive associations were also found regarding the frequency of fast-food consumption, impulsivity, screen time, preference for sugar-sweetened foods, and hours spent in sports clubs, in increasing order of effect size. Additionally, correlations were observed between friends' cognitive and school functioning and being bullied. No associations were seen for a preference for high-fat foods, weight concerns, and health-related quality of life. Finally, parental education and immigrant background were associated between friends in all countries except Sweden, where no associations were observed. Conclusion: Adolescent friends shared a number of weight-related characteristics. For weight measures per se, positive associations with friends' characteristics were only observed in adolescents with high parental education. Associations regarding energy-balance behaviors and indicators of school-related well-being did not differ by parental education. Parental education and immigrant background correlated positively in friends in most countries showing that social aggregation is already occurring in adolescence. The wide spectrum of friendship associations in weight-related traits and behaviors suggests that health promotion initiatives in adolescents should be directed towards peer groups in both school-related and leisure-time environments. ISRCTN Registry: Pan-European IDEFICS/I.Family children cohort (ID ISRCTN62310987; https://doi.org/10.1186/ISRCTN62310987)