Alginate-silver nanocomposites in the form of spherical beads and films were prepared using a green approach by using the aqueous extract of Ajwa date seeds. The nanocomposites were fabricated by in situ reduction and gelation by ionotropic crosslinking using calcium ions in solution. The rich phytochemicals of the date seed extract played a dual role as a reducing and stabilizing agent in the synthesis of silver nanoparticles. The formation of silver nanoparticles was studied using UV-Vis absorption spectroscopy, and a distinct surface plasmon resonance peak at 421 nm characteristic of silver nanoparticles confirmed the green synthesis of silver nanoparticles. The morphology of the nanocomposite beads and film was compact, with an even distribution of silver nanoclusters. The catalytic property of the nanocomposite beads was evaluated for the degradation of 2-nitrophenol in the presence of sodium borohydride. The degradation followed pseudo-first-order kinetics with a rate constant of 1.40 × 10−3 s−1 at 23 ℃ and an activation energy of 18.45 kJ mol−1. The thermodynamic parameters, such as changes in enthalpy and entropy, were evaluated to be 15.22 kJ mol−1 and −197.50 J mol−1 K−1, respectively. The nanocomposite exhibited properties against three clinically important pathogens (gram-positive and gram-negative bacteria).
The objective of this work was to evaluate the combined effect of bovine manure, Pseudomonas putida and Trichoderma aureoviride on the development of lettuce (Lactuca sativa). The promotion of plant growth by microorganisms may be a viable and sustainable alternative for lettuce crop management. The experimental design was entirely randomized with five treatments: T0 (witness without fertilization, P. putida and T. aureoviride), TE (cattle manure), TEB (cattle manure + P. putida), TEF (cattle manure + T. aureoviride), TEFB (cattle manure + P. putida + T. aureoviride) and ten repetitions each. The following variables were analyzed: germination velocity index (GVI), first count (FC), germination percentage (GP), leaf area index and productivity. The TEFB treatment proved to be a viable alternative for the production of lettuce, especially for small producers, since all the vegetable production in the region comes from family farming.
Introduction: Chest trauma has a high incidence and pneumothorax is the most frequent finding. The literature is scarce on what to do with asymptomatic patients with pneumothorax due to penetrating chest trauma. The aim of this study was to evaluate what are the findings of the control radiography of patients with penetrating chest trauma who are not initially taken to surgery, and their usefulness in determining the need for further treatment. Methods: A retrospective cohort study was performed, including patients older than 15 years who were admitted for penetrating chest trauma between January 2015 and December 2017 and who did not require initial surgical management. We analyzed the results of chest radiography, the time of its acquisition, and the behavior decided according to the findings in patients initially left under observation. Results: A total of 1,554 patients were included, whose average age was 30 years, 92.5% were male and 97% had a sharp weapon wound. Of these, 186 (51.5%) had no alterations in their initial X-ray, 142 had pneumothorax less than 30% and 33 had pneumothorax greater than 30 %, hemopneumothorax or hemothorax. Closed thoracostomy was required as the final procedure in 78 cases, sternotomy or thoracotomy in 2 cases and discharged in 281. Conclusion: In asymptomatic patients with small or moderate pneumothorax and no other significant lesions, longer observation times, radiographs and closed thoracostomy may be unnecessary.
The heat collection evaporator was modeled based on equilibrium homogeneous theory, and the Runge-Kutta calculation method was used to analyze and solve the flow in the heat collection evaporator. The influence of environmental factors such as solar irradiance, ambient temperature and wind speed on the variation of refrigerant pressure in two kinds of heat collecting evaporator was analyzed under the set working conditions. The results show that the solar energy irradiance has a great influence on the pressure drop in the tube of serpentine heat collecting evaporator, and the maximum pressure drop of the refrigerant in the tube is 16.3%, minimum pressure drop is 7.8%. However, it has little influence on the pressure drop of the tube sheet evaporator. The maximum pressure drop in the refrigerant tube of the tube sheet evaporator is 4.8%, minimum pressure drop is 1.8%. When the irradiance reaches 800 W/m2, the refrigerant in the serpentine-tube evaporator has been completely vaporized at 6 m, it’s completely vaporized at 3 m.
The Belt and Road Initiative (BRI) aims to enhance connectivity and collaboration among 60 countries and beyond in Asia, Africa and Europe. Information and communications technology (ICT) is an indispensable component of the initiative, critical in providing fundamental communication channels for global financial transactions, trade exchanges and transport and energy connectivity, and socio cultural collaboration and scientific exchanges between people, organizations and countries along the BRI corridors. Previously constrained by infrastructure deficits in ICT, the Asia-Pacific region is accelerating its efforts to provide reliable and affordable broadband networks throughout the region, to contribute to successful implementation of the Sustainable Development Goals (SDG).
Within the BRI corridors, this study which has been undertaken as part of the research programme of the United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) on promoting regional economic cooperation and integration, focuses on the China-Central Asia Corridor (China, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan), giving attention to the sub-region’s specific challenges, namely limited international transit opportunities and an increase in bandwidth requirements that is expected to grow exponentially, as the fourth industrial evolution centered on automation and artificial intelligence gathers momentum. The sub-region is characterized as highly dependent on the ease and costs of connecting to neighboring countries for transit, as many countries in the sub-region are landlocked developing countries (LLDC). Because of the geographical features and other factors, the development potential of Central Asia and its integration into globalization, continues to be stymied by insufficient international bandwidth and high transit costs to access international links. Therefore, improved ICT connectivity in Central Asia through the BRI corridor could result in improved availability and affordability of broadband networks and services in the sub-region.
For the purpose of this study, a gap analysis is the methodology that underpins the proposed topology for the China-Central Asia Corridor. The analysis included examining the current state of the optic infrastructure, such as existing and planned fiber-optic networks, existing Internet Exchange Points (IXPs) and international gateways. The study also identifies the key factors that determine the desired future state of infrastructure deployment for the BRI initiative. A topology that consists of connecting Almaty (Kazakhstan) and Urumqi (China), as core nodes, is proposed based on a partial mesh topology. Over and above this core finding, the study concludes that digital infrastructure connectivity has a tendency of lagging behind the rapid opportunities evolving, and the study therefore advocates for sub-regional and regional approaches, including the BRI and Asia-Pacific Information Superhighway (AP-IS) in further expanding regional broadband networks. A key recommendation of the study is co-deployment of broadband infrastructure along passive infrastructure, as an additional cost effective means of achieving fast and affordable broadband connectivity for all.
Copyright © by EnPress Publisher. All rights reserved.