Entrapment of hemocyanin conformers as a tool for the definition of the structural model of cooperativity

Allostery has been established as a fundamental mechanism of regulation in most biological processes (Changeux, 2012). The most studied allosteric protein is hemoglobin, that has long been considered a paradigm for the investigation of allostery and cooperativity in macromolecules (Cui & Karplus, 2008). A phenomenological characterization of the cooperative oxygen binding in hemoglobin has been given by the classic Monod, Wyman, Changeux model (MWC) (Monod et al., 1965), which described the cooperativity process as the allosteric transition between two different allosteric conformers: the high oxygen affinity R-state and the low oxygen affinity T-state. In this work we wanted to characterize the highly cooperative oxygen binding process of the hemocyanin (in its dodecameric state) from the arthropod Carcinus aesturaii, which represents a more complex case study. To this aim the functional and structural properties of the different conformational states were investigated, through the encapsulation of the hemocyanin into a sol-gel matrix to avoid the allosteric transition between T- and R-state. Firstly we characterized the structural and optical properties of the sol-gel matrix in order to find the better conditions for protein encapsulation. The effect of the pH, glycerol and aging time was assessed by collecting Small Angler X-Ray Scattering spectra of undoped sol-gel matrices at ELETTRA (Trieste, Italy). The fractal analysis of all the spectra did not evidence any significant effect of the three factors on the properties of the matrix, with the exception of the decrease of the radius of the silica particles that form the gel network in presence of glycerol. Moreover, the spectroscopic analysis of the undoped matrix revealed a good transparence of the matrix. The key point of the work was to evaluate if the sol-gel matrix was a suitable way for the entrapment of hemocyanin in a single conformational state, through the analysis of the oxygen binding curves and the Hill-plots of the hemocyanin entrapped into the silica matrix (in presence and absence of oxygen). The results suggested that the sol-gel matrix can avoid the allosteric transitions, although the full entrapment of distinct conformers strongly depend on the pH. Oxygen binding experiments performed in presence of different concentrations of salt demonstrated that changes of the charge to charge interactions between protein and matrix may play an important role in conformational entrapment. The entrapment of different conformers was confirmed by spectroscopic analysis that revealed small but significant differences in the shape of the CD-spectra in the aromatic region and shifts of the peaks of fluorescence emission for the two conformers. To verify if the oxygen equilibrium data were in agreement with the MWC model we compared the equilibrium constants of the curves obtained by the hemocyanin entrapped into the sol-gel with those predicted by the model, suggesting that the cooperativity in this hemocyanin occurs in a more complicated way. A three-state model was proposed. The validation of the three-state model was performed through Small Angle Neutron Scattering (SANS) measurements at ILL neutron radiation facility (Grenoble, France), that allowed us to characterize the structure of the conformers both in the oxy- and deoxygenated state. The analysis of the SANS spectra seems to confirm the presence of three different conformers, with a different arrangement of the two hexamers. In order to determine if these differences in the quaternary structure were correlated to changes in the active sties, we collected XAS spectra at ESRF (Grenoble, France), which shown differences between the different conformers, suggesting a different coordination geometry of the active sites in the deoxygenated form. An investigation of the functional and structural effects of the positive allosteric effector lactate was also performed, by the analysis of oxygen binding curves and SANS spectra. In conclusion, with this work it is defined a structural model of cooperativity for hemocyanin, with a functional and structural characterization of the different conformers. We also proposed a possible mechanism to describe how the quaternary conformational changes are linked to the different coordination geometry of the active site during the oxygen binding process. This study method can be exported to other cooperative systems and the results also provide a solid start point for the development of an oxygen biosensor

A Survey of Disaster Risk and Resilience in Small Island States

This paper surveys the conceptual framework of disaster risk that relies on its associated components of hazard, vulnerability and exposure. How we measure these risks depends on how we define disaster risk and its components. We focus on the implication and applicability of available conceptual frameworks of disaster risk on small and low-lying islands in the Pacific. We examine some of the available measurements of these disaster risks as they are imperative to the formulation of appropriate disaster risk reduction (DRR) policies for Tuvalu. Though there are diverse views on these definitions in different disciplines, we can capitalise on their commonalities to frame disaster risk models. Here, we intend to use the findings and set a pathway for potential research and to contribute into building resilience, reducing DRR and improving responsiveness to the impact of climatic disasters in Pacific Islands

The relationship between chief executive officer remuneration and financial performance in South Africa between 2006 and 2012

Orientation: The relationship between Chief Executive Officer (CEO) remuneration and organisation performance has been a topic of close scrutiny, especially since the global financial crisis. Optimal contracting relies on the premise that effective incentives will link organisation financial performance and CEO remuneration in ways that will be in the best interests of both shareholders and CEOs. Research purpose: The purpose of this research study was to investigate the relationship between CEO remuneration and organisation performance in South Africa between 2006 and 2012 and to determine whether the two constructs were positively correlated. Motivation for the study: The study provides an evidenced-based understanding of the nature of the CEO pay-performance relationship in South Africa. Understanding this relationship is critical to finding a suitable model to structure executive remuneration that will protect shareholders from over-remunerating executives in times of economic appreciation, whilst protecting executives from being underpaid in times of economic depreciation. Method: The financial results and CEO remuneration of 21 of the top 40 listed companies on the Johannesburg Stock Exchange were analysed for the period 2006–2012. The research was a quantitative, archival study. The primary statistical techniques used in the study were correlation analysis and multiple regression analysis. Main findings: The primary finding of the current research indicates that between 2006 and 2012 organisation executives have noticeably been moving away from focusing on short-term incentives, which are categorised as performance-related elements of remuneration packages. Based on these findings, it is evident that the relationship between executive remuneration and organisational financial performance has been experiencing a decline, especially since the 2008 global financial crisis. The decline has predominantly been due to a move away from performance-related elements of remuneration contracts by CEOs, creating a disconnect between CEO remuneration and organisational performance. The findings suggest that, to a large extent, remuneration contracts for CEOs are no longer optimal for the organisation and its shareholders, but are influenced by the propensity of executives to enhance their own remuneration. There exists a link between short-term incentives received by CEOs and accounting-based organisational performance measures; on the other hand, fixed pay linked with organisational performance measures continue to be eroded as organisations’ executives become more innovative as they are noticeably moving away from focusing on short-term incentives...

The relationship between chief executive officer remuneration and financial performance in South Africa between 2006 and 2012

ORIENTATION : The relationship between Chief Executive Officer (CEO) remuneration and organisation performance has been a topic of close scrutiny, especially since the global financial crisis. Optimal contracting relies on the premise that effective incentives will link organisation financial performance and CEO remuneration in ways that will be in the best interests of both shareholders and CEOs. RESEARCH PURPOSE : The purpose of this research study was to investigate the relationship between CEO remuneration and organisation performance in South Africa between 2006 and 2012 and to determine whether the two constructs were positively correlated. MOTIVATION FOR THE STUDY : The study provides an evidenced-based understanding of the nature of the CEO pay-performance relationship in South Africa. Understanding this relationship is critical to finding a suitable model to structure executive remuneration that will protect shareholders from over-remunerating executives in times of economic appreciation, whilst protecting executives from being underpaid in times of economic depreciation. METHOD : The financial results and CEO remuneration of 21 of the top 40 listed companies on the Johannesburg Stock Exchange were analysed for the period 2006–2012. The research was a quantitative, archival study. The primary statistical techniques used in the study were correlation analysis and multiple regression analysis. MAIN FINDINGS : The primary finding of the current research indicates that between 2006 and 2012 organisation executives have noticeably been moving away from focusing on short-term incentives, which are categorised as performance-related elements of remuneration packages. Based on these findings, it is evident that the relationship between executive remuneration and organisational financial performance has been experiencing a decline, especially since the 2008 global financial crisis. The decline has predominantly been due to a move away from performance-related elements of remuneration contracts by CEOs, creating a disconnect between CEO remuneration and organisational performance. The findings suggest that, to a large extent, remuneration contracts for CEOs are no longer optimal for the organisation and its shareholders, but are influenced by the propensity of executives to enhance their own remuneration. There exists a link between short-term incentives received by CEOs and accounting-based organisational performance measures; on the other hand, fixed pay linked with organisational performance measures continue to be eroded as organisations’ executives become more innovative as they are noticeably moving away from focusing on short-term incentives. PRACTICAL/MANEGERIAL IMPLICATIONS : A stronger test of the pay-performance link and the power of incentive design are required in order to ensure that executives are rewarded or penalised for poor performance. The question of how executives are paid also needs to be considered. CONTRIBUTION : This research contributes to the literature on CEO remuneration by providing an evidenced-based understanding of the nature of the CEO pay-performance relationship in South Africa. Understanding this relationship is critical to finding a suitable model to structure executive remuneration that will protect shareholders from over-remunerating executives in times of economic appreciation, whilst protecting executives from being underpaid in times of economic depreciation.http://www.sajhrm.org.zaam201

Structural Analysis Peer Review for the Static Display of the Orbiter Atlantis at the Kennedy Space Center Visitors Center

Mr. Christopher Miller with the Kennedy Space Center (KSC) NASA Safety & Mission Assurance (S&MA) office requested the NASA Engineering and Safety Center's (NESC) technical support on March 15, 2012, to review and make recommendations on the structural analysis being performed for the Orbiter Atlantis static display at the KSC Visitor Center. The principal focus of the assessment was to review the engineering firm's structural analysis for lifting and aligning the orbiter and its static display configuratio

Kinetics of substrate oxidation and hydrogen peroxide production by Mycoplasma mycoides subsp. mycoides Large Colony (LC) type and Mycoplasma mycoides subsp. capri

Mycoplasma mycoides subsp. mycoides Large Colony (LC) type is a pathogen of goats causing contagious agalactia and respiratory disease, found on all continents where small ruminants are kept. It shares close genetic characteristics with M. mycoides subsp. capri. Substrate oxidation by 22 strains of M. mycoides subsp. mycoides LC from nine countries was compared with that of eight strains of M. mycoides subsp. capri from five countries. There was considerable similarity in the substrates used, but substrate saturation coefficients (Ks) varied for different substrates. Substrate utilization patterns and Ks values did not (1) significantly differentiate the LC strains from each other, (2) show any correlation with geographical origin, or (3) distinguish the LC strains from the capri strains. These results support previous studies justifying the reclassification of these subspecies as a single species

A quasi randomized-controlled trial to evaluate the effectiveness of clowntherapy on children\u2019s anxiety and pain levels in emergency department

The aim of the study is to investigate if the presence of medical clowns during painful procedures in the emergency department (ED) affects children's anxiety and pain. Forty children (4-11 years) admitted to the ED with the need of painful procedures were prospectively enrolled. They were randomly assigned to the clown group, where children interacted with clowns or to the control group in which they were entertained by parents and ED nurses. The children's anxiety was assessed by the Children's Anxiety and Pain Scales; pain was evaluated with the Numerical Rating Scale and Wong-Backer Scale, according to the children's age. Staff and clown's opinions were evaluated by means of dedicated questionnaires. Children's anxiety levels in the clown group were significantly lower than those compared with the control group, while children's pain levels did not change between the two groups. CONCLUSION: The presence of clowns in the ED before and during painful procedures was effective in reducing children's anxiety. WHAT IS KNOWN: \u2022 Anxiety and fear caused by medical procedures exacerbate children's pain and may interfere with the procedure. \u2022 To reduce anxiety, fear, and pain and to facilitate patient's evaluation, different non-pharmacological approaches have been proposed and positive effects of laughter and humor have been reported. What is New: \u2022 The presence of clowns in the waiting room and in the ED during medical evaluation and painful procedures helps to reduce children's anxiet

Somatic symptom disorder was common in children and adolescents attending an emergency department complaining of pain

AIM: The aim of this study was to quantify the prevalence of somatic pain in a paediatric emergency department (ED). METHODS: We conducted a prospective observational study using patients admitted to the ED of an Italian children's hospital between December 2014 and February 2015. We enrolled children aged 7-17 who turned up at the ED complaining of pain. Patients and parents were asked to fill in a questionnaire to allow the analysis of the patients' medical history and provide contact details for follow-up. We divided the enrolled patients into four groups: post-traumatic pain, organic pain, functional pain and somatic pain. The questionnaire was used to define pain characteristics and to generate an impairment score. RESULTS: Of the 713 patients who met inclusion criteria, 306 (42.9%) were enrolled in the study. Of these, 135 (44.0%) suffered from post-traumatic pain, 104 (34.0%) from organic pain, 41 (13.4%) from functional pain and 26 (8.6%) from somatic pain. Somatic pain patients had endured pain longer, had missed more school days and had suffered severe functional impairment. CONCLUSION: This study highlighted that somatic pain was a significant contributor to paediatric emergency room visits and should be suspected and diagnosed in children reporting pain

REGULUS CubeSat Propulsion System: In-Orbit Operations

A robust, versatile, and cost-effective propulsion system to provide wide mobility to small satellite platforms and nanosatellite deployers. A Plug&Play propulsion system designed to be easily integrated into different satellite platforms and to match customer\u27s requirements, with minimal customization efforts and costs

Impact of prophylactic TNF blockade in the dual PD-1 and CTLA-4 immunotherapy efficacy and toxicity

The TNF blockade therapy is currently a well-established treatment option for a variety of autoimmune diseases such as rheumatoid arthritis (RA), psoriasis or Crohn's disease, given the proinflammatory role of TNF in the course of these diseases. Importantly, TNF neutralization is also used for the treatment of corticosteroid-refractory immune-related adverse events (irAEs) induced by the combined anti-PD-1 and anti-CTLA-4 immunotherapy. The manifestation of these toxicities is an important limiting factor for the successful implementation of the inhibitory checkpoint blockade therapy (ICB), restraining its anti-tumor efficacy. In our recent study (Perez-Ruiz et al., Nature 569(7756): 428-432.), we analyzed the potential impact of prophylactic TNF neutralization therapy in the anti-PD1/CTLA-4 efficacy. Through several mouse models, we demonstrated that TNF neutralization ameliorated ICB-exacerbated colitis in addition to improving ICB-dependent anti-tumor efficacy. Similar results were obtained after prophylactic TNF blockade in graft vs host xenografted mouse models with human immune cells, which showed a reduction in colitis and hepatitis. Importantly, there was a preservation of the immunotherapeutic control of xenografted tumors after ICB treatment. Moreover, TNF and TNF-dependent gene expression is upregulated in the colon mucosa from patients affected by colitis as a side effect of ipilimumab and nivolumab. Our results, thus, provide evidence of the successful combination of prophylactic TNF neutralization with ICB therapy strategy to ameliorate toxicities, while keeping or even ameliorating anti-tumor efficacy. The prophylactic TNF blockade strategy is clinically feasible since excellent TNF inhibitors have been approved for the treatment of autoimmunity and are used for the immune-related serious adverse events in immunotherapy