The molecular phylogeny of eph receptors and ephrin ligands

<p>Abstract</p> <p>Background</p> <p>The tissue distributions and functions of Eph receptors and their ephrin ligands have been well studied, however less is known about their evolutionary history. We have undertaken a phylogenetic analysis of Eph receptors and ephrins from a number of invertebrate and vertebrate species.</p> <p>Results</p> <p>Our findings indicate that Eph receptors form three major clades: one comprised of non-chordate and cephalochordate Eph receptors, a second comprised of urochordate Eph receptors, and a third comprised of vertebrate Eph receptors. Ephrins, on the other hand, fall into either a clade made up of the non-chordate and cephalochordate ephrins plus the urochordate and vertebrate ephrin-Bs or a clade made up of the urochordate and vertebrate ephrin-As.</p> <p>Conclusion</p> <p>We have concluded that Eph receptors and ephrins diverged into A and B-types at different points in their evolutionary history, such that primitive chordates likely possessed an ancestral ephrin-A and an ancestral ephrin-B, but only a single Eph receptor. Furthermore, ephrin-As appear to have arisen in the common ancestor of urochordates and vertebrates, whereas ephrin-Bs have a more ancient bilaterian origin. Ancestral ephrin-B-like ligands had transmembrane domains; as GPI anchors appear to have arisen or been lost at least 3 times.</p

Factors associated with HIV testing among male injecting drug users: findings from a cross-sectional behavioural and biological survey in Manipur and Nagaland, India

BACKGROUND: Although targeted interventions in India require all high-risk groups, including injecting drug users (IDUs), to test for HIV every 6 months, testing uptake among IDUs remains far from universal. Our study estimates the proportion of IDUs who have taken an HIV test and identifies the factors associated with HIV testing uptake in Nagaland and Manipur, two high HIV prevalence states in India where the epidemic is driven by injecting drug use. METHODS: Data are drawn from the cross-sectional Integrated Behavioural and Biological Assessment (2009) of 1650 male IDUs from two districts each of Manipur and Nagaland. Participants were recruited using respondent-driven sampling (RDS). Descriptive data were analysed using RDSAT 7.1. Multivariate logistic regression analysis was undertaken using STATA 11 to examine the association between HIV testing and socio-demographic, behavioural and programme exposure variables. RESULTS: One third of IDUs reported prior HIV testing, of whom 8 % had tested HIV-positive. Among those without prior testing, 6.2 % tested HIV-positive in the current survey. IDUs aged 25–34 years (adjusted odds ratio (OR) = 1.41; 95 % confidence interval (CI) = 1.03–1.93), married (Adjusted OR = 1.56; 95 % CI = 1.15–2.12), had a paid sexual partner (Adjusted OR = 1.64; 95 % CI = 1.24–2.18), injected drugs for more than 36 months (Adjusted OR = 1.38; 95 % CI = 1.06–1.81), injected frequently (Adjusted OR = 1.49; 95 % CI = 1.12–1.98) and had high-risk perception (Adjusted OR = 1.68; 95 % CI = 1.32–2.14) were more likely than others to test for HIV. Compared to those with no programme exposure, IDUs who received counselling, or counselling and needle/syringe services, were more likely to test for HIV. CONCLUSIONS: HIV testing uptake among IDUs is low in Manipur and Nagaland, and a critical group of HIV-positive IDUs who have never tested for HIV are being missed by current programmes. This study identifies key sub-groups—including early initiators, short duration and less frequent injectors, perceived to be at low risk—for promoting HIV testing. Providing needles/syringes alone is not adequate to increase HIV testing; additionally, interventions must provide counselling services to inform all IDUs about HIV testing benefits, facilitate visits to testing centres and link those testing positive to timely treatment and care

Crevasses detection in Himalayan glaciers using ground-penetrating radar

Identification and mapping of crevasses in glaciated regions is important for safe movement. However, the remote and rugged glacial terrain in the Himalaya poses greater challenges for field data collection. In the present study crevasse signatures were collected from Siachen and Samudra Tapu glaciers in the Indian Himalaya using ground-penetrating radar (GPR). The surveys were conducted using the antennas of 250 MHz frequency in ground mode and 350 MHz in airborne mode. The identified signatures of open and hidden crevasses in GPR profiles collected in ground mode were validated by ground truthing. The crevasse zones and buried boulder areas in a glacier were identified using a combination of airborne GPR profiles and SAR data, and the same have been validated with the high-resolution optical satellite imagery (Cartosat-1) and Survey of India mapsheet. Using multi-sensor data, a crevasse map for Samudra Tapu glacier was prepared. The present methodology can also be used for mapping the crevasse zones in other glaciers in the Himalaya

A conceptual knowledge visualisation framework for transfer of knowledge : an organisational context

Revolutionary advances in science and technology enables organisations to apply and optimise a world of visual and experiential learning in order to enhance the skills and knowledge of their employees. Furthermore, the volume and complexity of knowledge and information are such that unless a reporting structure is overlaid upon it, it may remain meaningless. Knowledge visualisation uses graphical representations to convey organisational knowledge, enabling employees to share and recall relevant knowledge. However, in order to assist organisations to create and transfer knowledge more effectively through knowledge visualisation, the aim of this study is to provide a conceptual knowledge visualisation framework for the transfer of knowledge for organisations. A conceptual knowledge visualisation framework was designed through a systematic literature review process where 15 organisational knowledge visualisation elements were identified. The 15 elements were grouped and presented in a 4-layered, embedded conceptual framework that organisations may apply to their knowledge visualisation efforts. By using such a framework, organisations may optimise learning and improve knowledge and skills of its employees.http://link.springer.combookseries/558hj2021Informatic

Critical success factors for dynamic enterprise risk management in responsive organisations : a factor analysis approach

Globalisation and technology advancements have disrupted the organisational landscape and with the proliferation of new technology; risk management is fundamental to transforming the business especially considering the dynamic nature of the digital society organisations now exist in. However, the challenge faced by the enterprise risk management (ERM) function operating in such a dynamic and transformative environment, is the capability to continuously innovate, evolve and transform its risk management processes to meet the needs of the organisation. Questionnaire survey research examined the relative importance of 18 critical success factors for dynamic ERM. Factor analysis revealed that the appropriate grouping of the 18 critical success factors (CSFs) are ERM charter, ERM processes, and ERM business alignment. These findings should empower organisations to identify risk management processes influencing agility in the risk management practise applied.http://link.springer.combookseries/558hj2020Informatic

Differential expression of FAK and Pyk2 in metastatic and non-metastatic EL4 lymphoma cell lines

The murine EL4 lymphoma cell line exists in variants that are either sensitive or resistant to phorbol 12-myristate 13-acetate (PMA). In sensitive cells, PMA causes Erk MAPK activation and Erk-mediated growth arrest. In resistant cells, PMA induces a low level of Erk activation, without growth arrest. A relatively unexplored aspect of the phenotypes is that resistant cells are more adherent to culture substrate than are sensitive cells. In this study, the roles of the protein tyrosine kinases FAK and Pyk2 in EL4 phenotype were examined, with a particular emphasis on the role of these proteins in metastasis. FAK is expressed only in PMA-resistant (or intermediate phenotype) EL4 cells, correlating with enhanced cell-substrate adherence, while Pyk2 is more highly expressed in non-adherent PMA-sensitive cells. PMA treatment causes modulation of mRNA for FAK (up-regulation) and Pyk2 (down-regulation) in PMA-sensitive but not PMA-resistant EL4 cells. The increase in Pyk2 mRNA is correlated with an increase in Pyk2 protein expression. The roles of FAK in cell phenotype were further explored using transfection and knockdown experiments. The results showed that FAK does not play a major role in modulating PMA-induced Erk activation in EL4 cells. However, the knockdown studies demonstrated that FAK expression is required for proliferation and migration of PMA-resistant cells. In an experimental metastasis model using syngeneic mice, only FAK-expressing (PMA-resistant) EL4 cells form liver tumors. Taken together, these studies suggest that FAK expression promotes metastasis of EL4 lymphoma cells