We collected multi-wave survey data to assess the lagged effects of entrepreneurial self-efficacy (ESE) and entrepreneurial orientation (EO) on firm performance over a five-year period. The results ...of our study indicate that ESE and EO are both positively associated with firm performance but in different, and interesting, ways. Entrepreneurially self-efficacious founder/managers may help improve the performance of very young firms but such benefits dissipate over time. An EO, on the other hand, does not appear to be particularly beneficial to very young firms. However, our results suggest an EO may play an increasingly valuable role as new firms mature.
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BFBNIB, FZAB, GIS, IJS, KILJ, NUK, OILJ, PILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Chikungunya virus (CHIKV) is an emerging arbovirus associated with several recent large-scale epidemics. The 2005-2006 epidemic on Reunion island that resulted in approximately 266,000 human cases ...was associated with a strain of CHIKV with a mutation in the envelope protein gene (E1-A226V). To test the hypothesis that this mutation in the epidemic CHIKV (strain LR2006 OPY1) might influence fitness for different vector species, viral infectivity, dissemination, and transmission of CHIKV were compared in Aedes albopictus, the species implicated in the epidemic, and the recognized vector Ae. aegypti. Using viral infectious clones of the Reunion strain and a West African strain of CHIKV, into which either the E1-226 A or V mutation was engineered, we demonstrated that the E1-A226V mutation was directly responsible for a significant increase in CHIKV infectivity for Ae. albopictus, and led to more efficient viral dissemination into mosquito secondary organs and transmission to suckling mice. This mutation caused a marginal decrease in CHIKV Ae. aegypti midgut infectivity, had no effect on viral dissemination, and was associated with a slight increase in transmission by Ae. aegypti to suckling mice in competition experiments. The effect of the E1-A226V mutation on cholesterol dependence of CHIKV was also analyzed, revealing an association between cholesterol dependence and increased fitness of CHIKV in Ae. albopictus. Our observation that a single amino acid substitution can influence vector specificity provides a plausible explanation of how this mutant virus caused an epidemic in a region lacking the typical vector. This has important implications with respect to how viruses may establish a transmission cycle when introduced into a new area. Due to the widespread distribution of Ae. albopictus, this mutation increases the potential for CHIKV to permanently extend its range into Europe and the Americas.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Between 2005 and 2007 Chikungunya virus (CHIKV) caused its largest outbreak/epidemic in documented history. An unusual feature of this epidemic is the involvement of Ae. albopictus as a principal ...vector. Previously we have demonstrated that a single mutation E1-A226V significantly changed the ability of the virus to infect and be transmitted by this vector when expressed in the background of well characterized CHIKV strains LR2006 OPY1 and 37997. However, in the current study we demonstrate that introduction of the E1-A226V mutation into the background of an infectious clone derived from the Ag41855 strain (isolated in Uganda in 1982) does not significantly increase infectivity for Ae. albopictus. In order to elucidate the genetic determinants that affect CHIKV sensitivity to the E1-A226V mutation in Ae. albopictus, the genomes of the LR2006 OPY1 and Ag41855 strains were used for construction of chimeric viruses and viruses with a specific combination of point mutations at selected positions. Based upon the midgut infection rates of the derived viruses in Ae. albopictus and Ae. aegypti mosquitoes, a critical role of the mutations at positions E2-60 and E2-211 on vector infection was revealed. The E2-G60D mutation was an important determinant of CHIKV infectivity for both Ae. albopictus and Ae. aegypti, but only moderately modulated the effect of the E1-A226V mutation in Ae. albopictus. However, the effect of the E2-I211T mutation with respect to mosquito infections was much more specific, strongly modifying the effect of the E1-A226V mutation in Ae. albopictus. In contrast, CHIKV infectivity for Ae. aegypti was not influenced by the E2-1211T mutation. The occurrence of the E2-60G and E2-211I residues among CHIKV isolates was analyzed, revealing a high prevalence of E2-211I among strains belonging to the Eastern/Central/South African (ECSA) clade. This suggests that the E2-211I might be important for adaptation of CHIKV to some particular conditions prevalent in areas occupied by ECSA stains. These newly described determinants of CHIKV mosquito infectivity for Ae. albopictus and Ae. aegypti are of particular importance for studies aimed at the investigation of the detailed mechanisms of CHIKV adaptations to its vector species.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Bone loss in aging is linked with chronic low-grade inflammation and the accumulation of marrowfat in animals and humans. Peroxisome proliferator-activated receptor gamma (PPARγ), an ...adipogenic regulator, plays key roles in these biological processes. However, studies of the roles of PPARγ in age-related bone loss and inflammation are lacking. We hypothesized that deletion of PPARγ in bone marrow mesenchymal lineage cells would reduce bone loss with aging, potentially through a reduction in fat-generated inflammatory responses and an increase in osteoblastic activity. In the present study, we show that mice deficient of PPARγ in Dermo1-expressing mesenchymal lineage cells (Dermo1-Cre:PPARγ fl/fl) have reduced fat mass and increased cortical bone thickness but that deficiency of PPARγ had limited effect on protection of trabecular bone with aging as demonstrated by dual-energy X-ray absorptiometry, µCT, and histomorphometric analyses. Conditional knockout of PPARγ reduced serum concentrations of adipokines, including adiponectin, resistin, and leptin, and reduced marrow stromal cell expression levels of inflammation-related genes. Inflammation genes involved in the interferon signaling pathway were reduced the most. These results demonstrate that disruption of the master adipogenic regulator, PPARγ, has a certain protective effect on aging-induced bone loss, suggesting that regulation of adipose function and modulation of interferon signaling are among the key mechanisms by which PPARγ regulates bone homeostasis during aging process.
IMPORTANCE: Despite the potential importance of understanding excess mortality among people with mental disorders, no comprehensive meta-analyses have been conducted quantifying mortality across ...mental disorders. OBJECTIVE: To conduct a systematic review and meta-analysis of mortality among people with mental disorders and examine differences in mortality risks by type of death, diagnosis, and study characteristics. DATA SOURCES: We searched EMBASE, MEDLINE, PsychINFO, and Web of Science from inception through May 7, 2014, including references of eligible articles. Our search strategy included terms for mental disorders (eg, mental disorders, serious mental illness, and severe mental illness), specific diagnoses (eg, schizophrenia, depression, anxiety, and bipolar disorder), and mortality. We also used Google Scholar to identify articles that cited eligible articles. STUDY SELECTION: English-language cohort studies that reported a mortality estimate of mental disorders compared with a general population or controls from the same study setting without mental illness were included. Two reviewers independently reviewed the titles, abstracts, and articles. Of 2481 studies identified, 203 articles met the eligibility criteria and represented 29 countries in 6 continents. DATA EXTRACTION AND SYNTHESIS: One reviewer conducted a full abstraction of all data, and 2 reviewers verified accuracy. MAIN OUTCOMES AND MEASURES: Mortality estimates (eg, standardized mortality ratios, relative risks, hazard ratios, odds ratios, and years of potential life lost) comparing people with mental disorders and the general population or people without mental disorders. We used random-effects meta-analysis models to pool mortality ratios for all, natural, and unnatural causes of death. We also examined years of potential life lost and estimated the population attributable risk of mortality due to mental disorders. RESULTS: For all-cause mortality, the pooled relative risk of mortality among those with mental disorders (from 148 studies) was 2.22 (95% CI, 2.12-2.33). Of these, 135 studies revealed that mortality was significantly higher among people with mental disorders than among the comparison population. A total of 67.3% of deaths among people with mental disorders were due to natural causes, 17.5% to unnatural causes, and the remainder to other or unknown causes. The median years of potential life lost was 10 years (n = 24 studies). We estimate that 14.3% of deaths worldwide, or approximately 8 million deaths each year, are attributable to mental disorders. CONCLUSIONS AND RELEVANCE: These estimates suggest that mental disorders rank among the most substantial causes of death worldwide. Efforts to quantify and address the global burden of illness need to better consider the role of mental disorders in preventable mortality.
The use of research evidence to underpin public health practice and policy decisions in local government is strongly promoted but its implementation has not been straightforward. This study aimed to ...explore the factors, relationships and processes that contribute towards accessing, using, and generating research evidence that is relevant to local authority public health and social care and shapes its practice.
Semi-structured individual interviews with elected councillors, officers directly involved with public health and social care and with community members from one urban unitary authority in South England were conducted. Interviews were audio recorded, transcribed verbatim and thematically analysed.
Fourteen participants took part in the semi-structured interviews. Local knowledge and evidence are prioritised, and anecdotal evidence is valued. The Director of Public Health was the principal source of information and support. Academics were rarely mentioned as information sources, and their involvement was ad hoc. The use of research evidence varied between individuals and departments, with wider engagement among public health specialists. Key barriers to the use of research evidence included access (not reported among public health professionals), research timeliness, local applicability, competence in finding and interpreting evidence and the role of research evidence within a political context. Public health and adult social care teams are not currently research active or research ready. Major barriers exist due to financial constraints and the socio-political context of local authorities. COVID-19 disrupted siloed ways of working, strengthening and opening potential collaborations within the local authority. This changed perspectives about the value of research but is likely time-limited unless underpinned by sustainable funding.
Creating strategic level roles within local government to work with the Director of Public Health to champion the research agenda and embedding researchers within and across teams would build capacity for local authorities to sustainably co-create, undertake, and use evidence to better inform future actions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Epigenetic control of gene expression is critical for normal fetal development. However, chromatin-related mechanisms that activate bone-specific programs during osteogenesis have remained ...underexplored. Therefore, we investigated the expression profiles of a large cohort of epigenetic regulators (>300) during osteogenic differentiation of human mesenchymal cells derived from the stromal vascular fraction of adipose tissue (AMSCs). Molecular analyses establish that the polycomb group protein EZH2 (enhancer of zeste homolog 2) is down-regulated during osteoblastic differentiation of AMSCs. Chemical inhibitor and siRNA knockdown studies show that EZH2, a histone methyltransferase that catalyzes trimethylation of histone 3 lysine 27 (H3K27me3), suppresses osteogenic differentiation. Blocking EZH2 activity promotes osteoblast differentiation and suppresses adipogenic differentiation of AMSCs. High throughput RNA sequence (mRNASeq) analysis reveals that EZH2 inhibition stimulates cell cycle inhibitory proteins and enhances the production of extracellular matrix proteins. Conditional genetic loss of Ezh2 in uncommitted mesenchymal cells (Prrx1-Cre) results in multiple defects in skeletal patterning and bone formation, including shortened forelimbs, craniosynostosis, and clinodactyly. Histological analysis and mRNASeq profiling suggest that these effects are attributable to growth plate abnormalities and premature cranial suture closure because of precocious maturation of osteoblasts. We conclude that the epigenetic activity of EZH2 is required for skeletal patterning and development, but EZH2 expression declines during terminal osteoblast differentiation and matrix production.
Osteogenic differentiation is initiated by transcriptional and post-transcriptional epigenetic mechanisms.
Inhibition of H3K27 methyltransferase EZH2 enhances osteogenic commitment of human mesenchymal progenitors, and its depletion in mouse mesenchymal cells causes multiple skeletal abnormalities.
EZH2 is required for skeletal patterning and bone formation.
EZH2-dependent epigenetic mechanisms control osteogenesis both in vitro and in vivo.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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