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To evaluate the effect of synthesised calixarenes as new inhibitors on the corrosion of steel in HCl media at various temperatures.

Calixarenes have been synthesised and tested as corrosion inhibitors. Gravimetric technique and potentiodynamic polarisation and impedance spectroscopy methods were used.

Calixarenes exhibited a good inhibition. Their efficiency decreases slightly with temperature.

It was found that the inhibition efficiency increases with the concentration of inhibitors to reach 92 per cent at 10⁻⁴M.

The efficiency of calixarene derivatives increases with the concentration and falls slowly with temperature to attain 84 per cent at 353 K range. Calixarenes can be used in chemical cleaning and pickling processes.

The originality of this work is to find an inhibitor to give protection close to 100 per cent.

The privatization of State Owned Enterprises (SOE) has significant implications for SOE stakeholders. However, the effects on stakeholders will vary depending on characteristics of the privatization process and the structure of the SOE. This paper identifies privatization process characteristics of wealth creation and wealth distribution, and describes SOE structures on a continuum between government corporation and government agency. The privatization effectiveness for stakeholders is discussed and examples provided for each classification of privatization.

The purpose of this study is to ascertain whether nonlinearities could be present in electricity loads observed in subtropical environments, where none or little heating is required, and whether threshold autoregressive (TAR)-type regime switching models could be advantageous in the modeling of those loads.

The actual observed load of a Brazilian regional electricity distributor from January 2013 to August 2012 was modeled using a popularly employed ARMA model for reference, and smooth and non-smooth TAR transition (non-linear) models were used as non-linear regime switching models.

Evidence of nonlinearities were found in the load series, and evidence was also found on the intrinsic resistance of this type of models to structural breaks in the data. Additionally, to reacting well to asymmetries in the data, these models avoid the use of exogenous variables. Altogether, this could prove to be a definite advantage of the use of such model alternatives.

However, even if the present work may have been limited by the observation frequency of the available data, it appears TAR models appear to be a viable alternative to forecasting short-term electricity loads. Nonetheless, additional research is required to achieve a higher accuracy of forecast data.

If such models can be successfully used, it will be a great advantage for electricity generators, as the computational effort involved in the use of such models is not significantly larger than regular linear ones.

To our knowledge, this type of research has not yet been made with subtropical/tropical electricity load data.

This paper aims to provide an insight into recent advancements and developments of robotics for Natural Orifice Transluminal Surgery (NOTES) procedures.

Following an introduction that highlights the evolution from Minimally Invasive Surgery (MIS) to NOTES in the medical field, this paper reviews the main robotics systems that have been designed and implemented for MIS and NOTES, summarising their advantages and limitations and remarking the technological challenges and the requirements that still should be addressed and fulfilled.

The state-of-the-art presented in this paper shows that the majority of the platforms created for NOTES are laboratory prototypes, and their performances are still far from being optimal. New solutions are required to solve the problems confronted by the proposed systems such as the limited number of DOFs, the limited resolution, the optimal fixation and stiffening of the instruments for enabling stable and precise operation, the effective transmission of forces to the tip tools, the improvement of the force feedback feeling and the proper visualization and spatial orientation of the surgical field. Advances in robotics can contribute significantly to the development and future implementation of the NOTES procedure.

This paper highlights the current trends and challenges ahead in robotics applied to NOTES procedure.

Fused deposition modelling (FDM) has gained popularity owing to its capability of producing complex and customized profiles at relatively low cost and in shorter periods. The study aims to extend the use of FDM printers for 3D printing of low melting point alloy (LMPA), which has applications in the electronics industry, rapid tooling, biomedical, etc.

Solder is the LMPA with alloy’s melting temperature (around 200°C) lower than the parent metals. The most common composition of the solder, which is widely used, is tin and lead. However, lead is a hazardous material having environmental and health deteriorating effects. Therefore, lead-free Sn89Bi10Cu non-eutectic alloy in the form of filament was used. The step-by-step method has been used to identify the process window for temperature, print speed, filament length (E) and layer height. The existing FDM printer was customized for the present work.

Analysis of infrared images has been done to understand discontinuity at a certain range of process parameters. The effect of printing parameters on inter-bonding, width and thickness of the layers has also been studied. The microstructure of the parent material and deposited bead has been observed. Conclusions were drawn out based on the results, and the scope for the future has been pointed out.

The experiments resulted in the process window identification of print speed, extrusion temperature, filament length and layer height of Sn89Bi10Cu which is not done previously.

The purpose of this paper is to explore the effects of low doses of caffeine (<3 mg/kg) on jumping performance using a meta-analysis.

The search for eligible studies was performed through six databases, with additional backward and forward citation tracking. A random-effects meta-analysis was performed to compare the effects of caffeine vs placebo on jump height. The methodological quality of the included studies was appraised using the physiotherapy evidence database checklist.

Eight studies were included in the review. They were classified as good or excellent methodological quality. The pooled number of participants across all studies was 203. Four studies provided caffeine in relative doses, ranging from 1 to 2 mg/kg. Four studies provided caffeine supplementation in absolute doses of 80, 150 or 200 mg. The meta-analysis found that caffeine ingestion increased vertical jump height (Cohen’s d: 0.21; 95% confidence interval: 0.10, 0.31; p < 0.001; +3.5%).

The present meta-analysis found that caffeine doses of ∼1 to 2 mg/kg enhance jumping height. The effects observed herein are similar to those with higher caffeine doses, which is relevant as low caffeine doses produce minimal side effects. For most individuals, a caffeine dose of ∼1 to 2 mg/kg is equivalent to an amount of caffeine in an energy drink, one to two cups of coffee, one to two pieces of caffeinated chewing gum or several cups of green tea.

Caffeine is a popular ergogenic aid, but its effects on swimming performance are not yet fully clear. Therefore, the purpose of this paper is to examine the effects of caffeine on swimming performance.

Crossover placebo-controlled studies that explored the effects of caffeine on swimming performance were included. Six databases were searched to find relevant studies with additional forward and backward citation tracking. The data were pooled in a random-effects meta-analysis.

Eight studies were included in the review. The main meta-analysis showed a significant ergogenic effect of caffeine ingestion on swimming performance (Cohen’s d: –0.20; 95% confidence interval: −0.32, −0.08; p = 0.0008; –1.7%). In the analysis for short-distance swimming events, caffeine ingestion had a significant ergogenic effect on swimming performance (Cohen’s d: –0.14; 95% confidence interval: –0.27, −0.01; p = 0.03; −1.4%). An ergogenic effect of caffeine was also found in the analysis for moderate-to-long swimming distance events (Cohen’s d: –0.36; 95% confidence interval: −0.67, −0.05; p = 0.02; −2.2%).

The present meta-analysis found that caffeine ingestion decreases the time needed to complete a given swimming event. While these ergogenic effects may be classified as small, they are likely important in swimming, where narrow margins commonly determine placings.

The article applies the citizen science phenomenon – i.e. lay people involvement in research endeavours aimed at pushing forward scientific knowledge – to healthcare. Attention is paid to initiatives intended to tackle the COVID-19 pandemic as an illustrative case to exemplify the contribution of citizen science to system-wide innovation in healthcare.

A mixed methodology consisting of three sequential steps was developed. Firstly, a realist literature review was carried out to contextualize citizen science to healthcare. Then, an account of successfully completed large-scale, online citizen science projects dealing with healthcare and medicine has been conducted in order to obtain preliminary information about distinguishing features of citizen science in healthcare. Thirdly, a broad search of citizen science initiatives targeted to tackling the COVID-19 pandemic has been performed. A comparative case study approach has been undertaken to examine the attributes of such projects and to unravel their peculiarities.

Citizen science enacts the development of a lively healthcare ecosystem, which takes its nourishment from the voluntary contribution of lay people. Citizen scientists play different roles in accomplishing citizen science initiatives, ranging from data collectors to data analysts. Alongside enabling big data management, citizen science contributes to lay people's education and empowerment, soliciting their active involvement in service co-production and value co-creation.

Citizen science is still underexplored in healthcare. Even though further evidence is needed to emphasize the value of lay people's involvement in scientific research applied to healthcare, citizen science is expected to revolutionize the way innovation is pursued and achieved in the healthcare ecosystem. Engaging lay people in a co-creating partnership with expert scientist can help us to address unprecedented health-related challenges and to shape the future of healthcare. Tailored health policy and management interventions are required to empower lay people and to stimulate their active engagement in value co-creation.

Citizen science relies on the wisdom of the crowd to address major issues faced by healthcare organizations. The article comes up with a state of the art investigation of citizen science in healthcare, shedding light on its attributes and envisioning avenues for further development.

The purpose of this paper is to explore the sources of caffeine and its utilization in different food products, along with its impact on human health in terms of benefits and adverse effect.

The papers reviewed were selected based on the following key descriptors such as caffeine, sources, trends of consumption, utilization, benefits and adverse effects, regulation and labelling.

There are many physiological effects of caffeine on respiratory, cardiovascular, gastrointestinal, reproductive and central nervous system. It has a positive effect in reducing the risk of diabetes, Alzheimer’s disease, Parkinson’s disease and liver injury and, at the same time, in improving mood, psychomotor performance and immune response. On the other hand, the negative effects of caffeine include addiction, cancer, heart diseases, insomnia, gastrointestinal disturbances and intoxication. As caffeine, when taken in large amount, is harmful, therefore as per the regulatory bodies, its concentration should not exceed the set limit, and its presence needs to be listed on the label of that particular food product. In a nutshell, it can be said that caffeine acts as a boon as well as bane because it possesses both beneficial and adverse effects.

This is a unique and comprehensive review that will provide a brief overview of sources, utilization, healthful as well as harmful effect of caffeine to the readers.

Libraries are currently undergoing a significant transformation, emerging as dynamic advocates for environmental sustainability, surpassing their conventional roles as mere repositories of knowledge. In today’s world, dominated by the growing climate crisis, these evolving institutions are poised to play a pivotal role in addressing climate change. However, they confront a range of challenges, including the need to establish sustainable operations, provide accessible climate information, engage diverse audiences and uphold ethical standards.

The research methodology used for this study involves an extensive review of literature. The authors analyze existing studies concerning green libraries and their role as catalysts for climate change action globally. This analysis draws from a variety of scholarly sources, encompassing articles, books and reports, to provide a comprehensive overview of the subject.

The findings indicate that despite the aforementioned challenges, libraries in developed countries worldwide have demonstrated noteworthy success through initiatives such as green building projects, community engagement programs, collaborative partnerships, expansion of digital resources, innovative climate literacy initiatives and a commitment to ethical stewardship. These achievements serve as a source of inspiration, fostering hope and spurring action as libraries empower communities to embrace environmental stewardship. They showcase the potential of libraries as catalysts for positive environmental change.

The originality and value of this research lie in its insights into the potential of green libraries initiative as a catalyst for climate change action. Ultimately, this study opens the door to untold literary exploration, revolutionizing the art of green library capacity in the ever-evolving technological landscape. To augment their impact, libraries are encouraged to broaden the scope of their climate education initiatives, expand their digital resources, cultivate strategic collaborations, prioritize ethical responsibility and implement thorough evaluation and communication practices.