Twisting and tweezing the spin wave: on vortices, skyrmions, helical waves, and the magnonic spiral phase plate

Spin waves are the low-energy excitations of magnetically ordered materials. They are key elements in the stability analysis of the ordered phase and have a wealth of technological applications. Recently, we showed that spin waves of a magnetic nanowire may carry a definite amount of orbital angular momentum components along the propagation direction. This helical, in addition to the chiral, character of the spin waves is related to the spatial modulations of the spin wave phase across the wire. It, however, remains a challenge to generate and control such modes with conventional magnetic fields. Here, we make the first proposal for a \textit{magnetic} spiral phase plate by appropriately synthesizing two magnetic materials that have different speeds of spin waves. It is demonstrated with full-numerical micromagnetic simulations that despite the complicated structure of demagnetization fields, a homogeneous spin wave passing through the spiral phase plate attains the required twist and propagates further with the desired orbital angular momentum. While excitations from the ordered phase may have a twist, the magnetization itself can be twisted due to internal fields and forms what is known as a magnetic vortex. We point out the differences between both types of magnetic phenomena and discuss their possible interaction.Comment: 6 pages, 5 figure

Advanced Machine Learning Approach of Power Flow Optimization in Community Microgrid

With the increasing penetration of distributed renewable energy (DERs), the electrical grid is experiencing, on a daily basis, rapid and massive fluctuations in power and voltage profiles. Fast and precise control strategies in realtime have played an important role to ensure that the power system operates at an optimal status. Solving real-time optimal power flow (OPF) problems while satisfying the operational constraints of the community microgrid (CMG) is considered a promising technique to control the fluctuations of renewable sources and loads. This paper adopts a new deep reinforcement learning algorithm (DRL), called Twin-Delayed Deep Deterministic Policy Gradient (TD3), to solve the real-time OPF with consideration of DERs and distributed energy storages (DESs) in the CMG. Training and testing of the algorithm are conducted on an IEEE 14-bus test system. Comparative results show the effectiveness of the proposed algorithm

Real-time Energy Management in Smart Homes through Deep Reinforcement Learning

In light of the growing prevalence of distributed energy resources, energy storage systems (ESs), and electric vehicles (EVs) at the residential scale, home energy management (HEM) systems have become instrumental in amplifying economic advantages for consumers. These systems traditionally prioritize curtailing active power consumption, often at an expense of overlooking reactive power. A significant imbalance between active and reactive power can detrimentally impact the power factor in the home-to-grid interface. This research presents an innovative strategy designed to optimize the performance of HEM systems, ensuring they not only meet financial and operational goals but also enhance the power factor. The approach involves the strategic operation of flexible loads, meticulous control of thermostatic load in line with user preferences, and precise determination of active and reactive power values for both ES and EV. This optimizes cost savings and augments the power factor. Recognizing the uncertainties in user behaviors, renewable energy generations, and external temperature fluctuations, our model employs a Markov decision process for depiction. Moreover, the research advances a model-free HEM system grounded in deep reinforcement learning, thereby offering a notable proficiency in handling the multifaceted nature of smart home settings and ensuring real-time optimal load scheduling. Comprehensive assessments using real-world datasets validate our approach. Notably, the proposed methodology can elevate the power factor from 0.44 to 0.9 and achieve a significant 31.5% reduction in electricity bills, while upholding consumer satisfaction

E. coli in tropical urban rivers : a case study of the Sungai Gombak basin

The primary study area is Sg. Gombak, a river that flows through the mostly urbanized state of Selangor and transcends the capital of Malaysia, Kuala Lumpur. The study aims to characterize E. coli, organics and nutrients on the main stem of the river and its tributaries of Sg. Batu and Sg. Kerayong. There were 28 identified spatial sampling stations throughout the basin. The results on the upper reaches of Sg. Gombak showed E. coli levels ranged between 100 – 400 cfu/100mL. The levels increased and remained between 11,000 cfu/100mL to 18,000 cfu/100 mL downstream upon receiving sewage effluent and other pollution sources. This was comparable to Sg. Batu. Conditions were even worse in Sg. Kerayong as E. coli levels were in excess of 140,000 cfu/100 mL. Ambient temperature increase in excess of 30°C with a ∆T rise of 3 to 4°C appeared to result in some decrement of E. coli; at 0.08/°C for Sg. Gombak and 0.20/°C for Sg. Batu, albeit this only occurred at single spatial points in both rivers. Variation in BOD5, NH3-N and NO3-N did not appear to significantly influence bacterial count in the basin. The study results also showed for the water to be deemed suitable for skin contact, a removal efficiency of at least 92% has to be achieved, which in turn, translated to a die-off period of at least two hours

Impact of Porous Silica Nanosphere Architectures on the Catalytic Performance of Supported Sulphonic Acid Sites for Fructose Dehydration to 5‐Hydroxymethylfurfural

5‐hydroxymethylfurfural represents a key chemical in the drive towards a sustainable circular economy within the chemical industry. The final step in 5‐hydroxymethylfurfural production is the acid catalysed dehydration of fructose, for which supported organoacids are excellent potential catalyst candidates. Here we report a range of solid acid catalysis based on sulphonic acid grafted onto different porous silica nanosphere architectures, as confirmed by TEM, N2 porosimetry, XPS and ATR‐IR. All four catalysts display enhanced active site normalised activity and productivity, relative to alternative silica supported equivalent systems in the literature, with in‐pore diffusion of both substrate and product key to both performance and humin formation pathway. An increase in‐pore diffusion coefficient of 5‐hydroxymethylfurfural within wormlike and stellate structures results in optimal productivity. In contrast, poor diffusion within a raspberry‐like morphology decreases rates of 5‐hydroxymethylfurfural production and increases its consumption within humin formation

Viability-reducing activity of Coryllus avellana L. extracts against human cancer cell lines

The increasing rate of cancer incidence has encouraged the search for novel natural sources of anticancer compounds. The presence of small quantities of taxol and taxanes in Corylus avellana L. has impelled new potential applications for this plant in the field of biomedicine. In the present work, the cell viability-reducing activity of stems and leaves from three different hazel trees was studied against three human-derived cancer cell lines (HeLa, HepG2 and MCF-7). Both leaf and stem extracts significantly reduced viability of the three cell lines either after maceration with methanol or using taxane extraction methods. Since maceration reduced cell viability to a greater extent than taxane extraction methods, we scaled up the maceration extraction process using a method for solid/liquid extraction (Zippertex technology). Methanol leaf extracts promoted a higher reduction in viability of all cell lines assayed than stem extracts. Fractionation of methanol leaf extracts using silica gel chromatography led to the purification and identification of two compounds by HPLC-MS and NMR: (3R,5R)-3,5-dihydroxy-1,7-bis(4-hydroxyphenyl) heptane 3-O-β-d-glucopyranoside and quercetin-3-O-rhamnoside. The isolated compounds decreased viability of HeLa and HepG2 cells to a greater extent than MCF-7 cells. Our results suggest a potential use of C. avellana extracts in the pharmacotherapy of cervical cancer and hepatocarcinoma and, to a lesser extent, breast cancer

Isolation and characterization of halophilic bacteria producing exopolymers with emulsifuing and antioxidant activities

Halophilic bacteria are considered a great source of new strains producing novel exopolymers with functional properties. In this work we isolated ten halophilic strains producing exopolymers from different hypersaline environments in Morocco. Phenotypic characterization showed that the strains were moderately halophilic, mesophilic and neutrophilic with the ability to produce some hydrolytic enzymes. Strains identification based on 16S rRNA gene sequences comparison showed that nine strains, designed as N1, N2, N5, N7, N8, N9, N10, N11 and N12 belong to Halomonas genus and one strain, designed as N4, to Marinobacter genus. The majority of the strains showed high levels of exopolymer production. The study of emulsifying and antioxidant activities revealed that all the polymers have an interesting emulsifying and antioxidant activities with the polymer from Marinobacter sp. N4 forming the highest and most stable emulsions and exhibiting the best antioxidant activity in comparison with other exopolymers produced by Halomonas strains. The obtained results demonstrate the great potential of exopolymers from halophilic bacteria to be applied as emulsifying and antioxidant agents in food, cosmetics and oil industries

TAT-peptide conjugated repurposing drug against SARS-CoV-2 main protease (3CLpro): potential therapeutic intervention to combat COVID-19

The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that originated in Chinese city of Wuhan has caused around 906,092 deaths and 28,040,853 confirmed cases worldwide (WHO, 11 September, 2020). In a life-threatening situation, where there is no specific and licensed anti-COVID-19 vaccine or medicine available; the repurposed drug might act as a silver bullet. Currently, more than 211 vaccines, 80 antibodies, 31 antiviral drugs, 35 cell-based, 6 RNA-based and 131 other drugs are in clinical trials. It is therefore utter need of the hour to develop an effective drug that can be used for the treatment of COVID-19 before a vaccine can be developed. One of the best-characterized and attractive drug targets among coronaviruses is the main protease (3CL^{pro}). Therefore, the current study focuses on the molecular docking analysis of TAT-peptide^{47–57} (GRKKRRQRRRP)-conjugated repurposed drugs (i.e., lopinavir, ritonavir, favipiravir, and hydroxychloroquine) with SARS-CoV-2 main protease (3CL^{pro} to discover potential efficacy of TAT-peptide (TP) - conjugated repurposing drugs against SARS-CoV-2. The molecular docking results validated that TP-conjugated ritonavir, lopinavir, favipiravir, and hydroxychloroquine have superior and significantly enhanced interactions with the target SARS-CoV-2 main protease. In-silico approach employed in this study suggests that the combination of the drug with TP is an excelling alternative to develop a novel drug for the treatment of SARS-CoV-2 infected patients. The development of TP based delivery of repurposing drugs might be an excellent approach to enhance the efficacy of the existing drugs for the treatment of COVID-19. The predictions from the results obtained provide invaluable information that can be utilized for the choice of candidate drugs for in vitro, in vivo and clinical trials. The outcome from this work prove crucial for exploring and developing novel cost-effective and biocompatible TP conjugated anti-SARS-CoV-2 therapeutic agents in immediate future

How Trade Liberalization and Labor Development Could Coincide in the Philippines

As the world adapts to the rapid pace of globalization in the 21st century, countries ease trade restrictions by gradually removing tariffs and non-tariff barriers to incentivize the free flow of goods across nations. This prevalence of trade liberalization policies propelled policymakers and economists to investigate the relationship between trade reforms and economic outcomes including wage inequality around the world. They found that trade liberalization, on average, has had a positive impact on economic growth, but prior studies that examine the effects of trade liberalization on wage inequality in developing countries have found mixed results. Recently, Murakami (2021) examined the impact of trade liberalization on wage inequality in Chile through the reduction in effective tariffs brought about by the regional trade agreements of the country. Following his empirical strategy, we examine the impact of trade liberalization on wage inequality in the Philippines. In this policy brief, we provide insights on our findings and policy recommendations that the Philippines can undertak