Complete Transition Research Articles

Transient agonism of the sonic hedgehog pathway triggers a permanent transition of skin appendage fate in the chicken embryo.

Vertebrate skin appendage early development is mediated by conserved molecular signaling composing a dynamical reaction-diffusion-like system. Variations to such systems contribute to the remarkable diversity of skin appendage forms within and among species. Here, we demonstrate that stage-specific transient agonism of sonic hedgehog (Shh) pathway signaling in chicken triggers a complete and permanent transition from reticulate scales to feathers on the ventral surfaces of the foot and digits. Resulting ectopic feathers are developmentally comparable to feathers adorning the body, with down-type feathers transitioning into regenerative, bilaterally symmetric contour feathers in adult chickens. Crucially, this spectacular transition of skin appendage fate (from nodular reticulate scales to bona fide adult feathers) does not require sustained treatment. Our RNA sequencing analyses confirm that smoothened agonist treatment specifically promotes the expression of key Shh pathway-associated genes. These results indicate that variations in Shh pathway signaling likely contribute to the natural diversity and regionalization of avian integumentary appendages.

Modern accounting in foreign countries and the Republic of Belarus: models, evaluation and automation

Accounting models are considered and classified. The level of development of accounting systems of foreign countries is revealed. The degree of complexity of national accounting and taxation systems is reflected, the main evaluation criteria are determined.It has been determined that the main direction of improving accounting is a complete transition to an automated type of accounting, which will improve the level and quality of decisions made.

Convergence study for composite gas flow in pipes

AbstractUtilizing hydrogen in energy sources plays a crucial step towards a complete transition to renewable energies since production at‐scale is possible. The study works towards developing monitoring and control strategies of proportionally induced hydrogen in existing pipeline infrastructure. With this aim, a scalable model is utilized to compute the flow of composite gas along a pipe. The transient model is solved using finite element discretization and error convergence is studied for a test case. Coupling of species transport to track mixture composition along the pipe is also studied for a test case and error behaviors are investigated. Finally, simulations performed for a practical testcase are compared with a recently available open‐source tool for studying flow dynamics. The study highlights the deployment and usage of state‐of‐the‐art simulation tools against existing industrial necessities while providing invaluable insights into dynamics of gas mixtures.

Kinetic Control of Solvate Intermediate Evolution for High-Performance Perovskite Solar Cells by the Facial Mask Incubation Technique

The growth of high-quality perovskite films is complicated by the fact of uncontrollable crystallization pathways from perovskite precursors. During solution processing, extensive undesired nonperovskite products including residual solvate intermediates are produced due to quick solvent evaporation, which will adversely affect the efficiency and stability of perovskite solar cells (PSCs). Herein, we developed a highly efficient phase-transition pathway using a polydimethylsiloxane (PDMS)-based facial mask (FM) incubation technique, which enables significant reduction of the perovskite crystallization rate and depression of perovskite aggregation behavior. A surprising finding reveals that this technique induces complete phase transition from solvate intermediates to the perovskite phase, thereby obtaining phase-pure perovskite film. Meanwhile, a high-quality perovskite film with a shiny smooth surface, decreased defect states, and alleviated lattice strain is achieved after utilizing the FM strategy. Consequently, the target-inverted PSCs deliver a respectable efficiency of ∼21% and superior stability in both shelf storage (over 3700 h with 90% of initial efficiency) and light soaking (over 1000 h with 80% of initial efficiency) conditions. Our work highlights the importance of eliminating residual solvate intermediates to construct high-quality perovskites with excellent phase purity for ongoing production of high-performance perovskite-based optoelectronic devices.

Transition from hierarchy to adhocratic organizational culture in a Ukrainian university: From survival to successful development in the conditions of war

This study aims to investigate the transformation of organizational culture during year of the of the active phase of the russian-Ukrainian war that contributes to the survival of Bogdan Khmelnitsky Melitopol State Pedagogical University as an organization and is a factor in the transition from the survival to the phase of successful and dynamic development. Due to the war and the occupation of certain territories of Ukraine, the university was forced to relocate to the free territory in the city of Zaporizhzhia. It lost all its buildings and other material resources; around 25% of students, 25% of faculty, and 25% of funding. Despite the extreme conditions of the university’s functioning and the stress of teachers and students under constant attacks on civilians by the occupiers, the university has resumed its educational process and research. A formal sign of the success of the scientific work is the growth of the university’s position in the Consolidated ranking of Ukrainian universities. In the educational sphere, interdisciplinary academic programs have become a significant trend during the war. Innovations in management ensured that the university quickly adapted to the extreme environment. These innovations were primarily related to transitioning from a hierarchy to an adhocratic organizational culture. The main areas of changes in the university management were: renewal of the personal composition of the university management, reorganization of structural units, updating of the system of university regulations, and complete transition to electronic document management.

Injectable, self-healable and antibacterial multi-responsive tunicate cellulose nanocrystals strengthened supramolecular hydrogels for wound dressings

Wound dressing with an improved structural and functional recapitulation of damaged organs, efficient self-healing and antibacterial properties that can well integrate with tissue are urgently needed in wound management. Supramolecular hydrogels confer control over structural properties in a reversible, dynamic and biomimetic fashion. Herein, a kind of injectable, self-healing and antibacterial supramolecular hydrogel with multi-responses were fabricated by mixing phenylazo-terminated Pluronic F127, quaternized chitosan-graft-cyclodextrin and polydopamine coated tunicate cellulose nanocrystals under physiological conditions. By exploiting the photoisomerization of azobenzene under different wavelengths, a supramolecular hydrogel featuring a changing crosslink density of network was obtained. The corporation of polydopamine coated tunicate cellulose nanocrystals strengthens the hydrogel network with Schiff base bonds and hydrogen bonds, which avoids complete gel-sol transition. The inherent antibacterial property, drug release behavior, self-healing ability, hemostatic performance and biocompatibility were investigated to confirm superiority in wound healing. Moreover, the curcumin loaded hydrogel (Cur-hydrogel) showed multi-responsive release profiles (light, pH, and temperature). A full-thickness skin defect model was built to confirm that Cur-hydrogels significantly accelerated wound healing rate with better granulation tissue thickness and collagen disposition. Overall, the novel photo-responsive hydrogel with coherent antibacterial property has great potential in the healthcare of wound healing.

An online reinforcement learning approach to charging and order-dispatching optimization for an e-hailing electric vehicle fleet

Given the uncertainty of orders and the dynamically changing workload of charging stations, how to dispatch and charge electric vehicle (EV) fleets becomes a significant challenge facing e-hailing platforms. The common practice is to dispatch EVs to serve orders by heuristic matching methods but enable EV drivers to independently make charging decisions based on their experiences, which may compromise the platform’s performance. This study proposes a Markov decision process to jointly optimize the charging and order-dispatching schemes for an e-hailing EV fleet, which provides pick-up services for passengers only from a designated transportation hub (i.e., no pick-up from different locations). The objective is to maximize the total revenue of the fleet throughout a finite horizon. The complete state transition equations of the EV fleet are formulated to track the state-of-charge of their batteries. To learn the charging and order-dispatching policy in a dynamic stochastic environment, an online approximation algorithm is developed, which integrates the model-based reinforcement learning (RL) framework with a novel SARSA(Δ)-sample average approximation (SAA) architecture. Compared with the model-free RL algorithm and approximation dynamic programming (ADP), our algorithm explores high-quality decisions by an SAA model with empirical state transitions and exploits the best decisions so far by an SARSA(Δ) sample-trajectory updating. Computational results based on a real case show that, compared with the existing heuristic method and the ADP in the literature, the proposed approach increases the daily revenue by an average of 31.76% and 14.22%, respectively.

Long term lithium availability and electric mobility: What can we learn from resource assessment?

A more sustainable global mobility system in which Internal Combustion Engine (ICE) vehicles are replaced by electric vehicles (EVs) powered by lithium-ion batteries (LiBs), taking into account the existing, or inferred, resource, is still possible? The present study aims at providing an answer to this question, through the design of an innovative compartmental model. Model scenarios have been considered accounting for three different estimates of the resource, i.e. the declared reserves, the hypothesized resources, and the full beneficiation of dissolved Li in the oceans. Input data were provided from the historical data of Li primary production, EVs production and recycling rates.The replacement of the ICE vehicles fleet appears possible only under extreme, unrealistic situations, unless the Li “stored” in the oceans is considered exploitable. The main viable policies, i.e. the optimisation of the resource share (almost entirely devoted to mobility issues) and of recycling strategies (pushed up to >90 %) have a modest effect on the achievement of fleet replacement. The total amount of geological lithium resources results as the main limiting factor for the complete transition to EVs. According to the developed model, the peak of production would occur between 2078 and 2130, unless seawater Li is accounted for.The future of the global mobility in a resource-constrained world should be driven toward a model based on the service rather than the individual property of vehicles. Planning a total number of electric vehicles able to assure long term sustainability will be also highly relevant.

The Study of Total Sediment Transport Characteristics at Kanching Forest Waterfall

Families and environment enthusiasts frequently visit Kanching Rainforest Waterfall, also known as Kanching Recreational Forest. It is located nearby in the Rawang neighbourhood to the north of Kuala Lumpur and has an area of around 47,000 square metres. Due to its proximity to the city, the region has become a popular place for people to enjoy picnics, camping, swimming, and jungle walks during the holidays. The movement or discharge of water flow is closely related with sediment. Since a specific discharge is necessary to propel and carry particles of a particular weight or size along the pathways. In essence, sediment estimates are so crucial because rivers in Malaysia continue to fill reservoirs with river water for daily use. Sedimentation in reservoirs can reduce the amount of accessible water, hence restricting its application. In this study, the Hjulström graph were used to predict the sediments and particles flow distributions, and the correlation between particle size and particle mobility in the flows of rivers was determined at three (3) checkpoints to examine the sediments and particles flow distributions. According to the data obtained, Checkpoint 1 has a particle velocity of around 0.4703 N/s, or 40 grammes per second, whereas Checkpoint 2 has a velocity of roughly 1.534 N/s, or 156 grammes per second. Lastly, Checkpoint 3 lacks a full load transfer. In addition to preserving one of the region's leisure areas, the significance of complete load transit estimation will ensure its maintenance. By using this method, the estimation of the total load that may be eroded along the river by calculating the total transport load can be forecasted hence, provide a maintenance program toward the rehabilitation of the Kanching Recreational Forest.

One-Step Fabrication of Droplet Arrays Using a Biomimetic Structural Chip.

In the field of one-step efficient preparation of dewetting droplet arrays, the process is hampered by the requirement for low chemical wettability of solid surfaces, which restricts the complete transition of wetting state and its broad prospects in biological applications. Inspired by the physical structure of the lotus leaf, enabling it to promote the change of the infiltration state of an aqueous solution on the surface, we developed a method of one-step fabrication of droplet arrays on the biomimetic structural chip designed in the present work. This greatly reduces the need for chemical modification techniques to achieve low wettability and reduces the reliance on complex and sophisticated surface preparation techniques, thus improving the fabrication efficiency of droplet arrays fully generated on a chip by one-step operation without the need for extra liquid phase or the control of harsh barometric pressure. We also studied the influence of dimensions of the biomimetic structure and the preparation process parameters such as number of smears and speed of smearing on the preparation rate and uniformity of the droplet arrays. The amplification of templating DNA molecules in the droplet arrays prepared in a one-step fabrication way is also performed to verify its application potential for DNA molecular diagnosis.

Fiscal rules and the cyclicality of fiscal policy in the East African community

ABSTRACT We examine the cyclicality of government expenditure and the impact of fiscal rules in a panel of five East African Community (EAC) countries using annual data for the period 1980–2019. The analysis is based on pooled ordinary least squares and panel autoregressive distributed lag regressions. We find that government consumption is acyclical while investment is procyclical. In addition, we find suggestive evidence that fiscal policy became less procyclical following the adoption of fiscal rules consistent with the EAC macroeconomic convergence criteria. These results highlight the importance of strengthening the scope and implementation of existing fiscal rules to facilitate the complete transition to countercyclical fiscal policy stance.

Re-examining the Entry-to-Practice PharmD Experiment

Since 2000, the Doctor of Pharmacy degree has served as the entry-level credential for pharmacy practice in the United States, Some 20-plus years following the complete transition to an entry-level clinical doctorate in pharmacy, a re-examination of the outcomes of this move and the trajectory of the profession is merited. Particular attention might be given to the increasing diversity within pharmacy and the myriad of practice types. Regardless of the path forward, intentional and critical appraisals of both the pros and cons of the entry-level Doctor of Pharmacy, as well as the future of pharmacy practice, are warranted. Nursing is a case study in contrast to pharmacy, with its multiple degree and training programs and its hierarchical and graded system of practice. Nursing practice clearly links progressive levels of education to increasing clinical privileges.

Landau theory-based relaxational modeling of first-order magnetic transition dynamics in magnetocaloric materials

The magnetocaloric effect is often largest within the neighborhood of a first-order phase transition. This effect can be utilized in magnetocaloric refrigeration, which completely eliminates the need for the greenhouse gases utilized in conventional refrigeration. However, such transitions present unique dynamical effects and are accompanied by hysteresis, which can be detrimental for such refrigeration applications. In this work, a Landau theory-based relaxational model is used to study the magnetic hysteresis and dynamics of the first-order magnetic transition of LaFe13−x Si x . Fitting the experimental magnetization data as a function of applied magnetic field under different field sweep rates with this model provided the Landau parameters (A, B, and C) and the kinetic coefficient of the studied material. We demonstrate the tendency of the magnetic hysteresis to increase with the magnetic field sweep rate, underlining the importance of studying and minimizing the magnetic hysteresis in magnetic refrigerants at practical field sweep rates. While evaluating the temperature dependence of the time required for a complete transition to occur, a nonmonotonic behavior and a sharp peak were found for temperatures near the transition temperature. Such peaks occur at the same temperature as the peak of the magnetic entropy change for low fields, whereas for higher fields the two peaks decouple. This information is critical for technological applications (such as refrigerators/heat pumps) as it provides guidelines for the optimization of the magnetic field amplitude in order to reduce the transition timescale and consequently maximize the machine operational frequency and amount of heat that is pumped in/out per second.

Spinel-Derived Formation and Amorphization of Bimetallic Oxyhydroxides for Efficient Electrocatalytic Biomass Oxidation

Replacing the oxygen evolution reaction (OER) with water-assisted oxidation of organic molecules represents a promising approach for achieving sustainable electrochemical biomass utilization. Among numerous OER catalysts, spinels have received substantial attention due to their manifold compositions and valence states, yet their application in biomass conversions remains rare. Herein, a series of spinels were investigated for the selective electrooxidation of furfural and 5-hydroxymethylfurfural, two model substrates for versatile value-added chemical products. Spinel sulfides universally exhibit superior catalytic performance compared to that of spinel oxides, and further investigations show that the replacement of oxygen with sulfur led to the complete phase transition of spinel sulfides into amorphous bimetallic oxyhydroxides during electrochemical activation, serving as the active species. Excellent values of conversion rate (100%), selectivity (100%), faradaic efficiency (>95%), and stability were achieved via sulfide-derived amorphous CuCo-oxyhydroxide. Furthermore, a volcano-like correlation was established between their BEOR and OER activities based on an OER-assisted organic oxidation mechanism.

Iron(II) Complexes of 2,6-Di[4-(ethylcarboxy)pyrazol-1-yl]pyridine with Reversible Guest-Modulated Spin-Crossover Behavior.

Three solvatomorphs of the iron(II) complex of 2,6-di[4-(ethylcarboxy)pyrazol-1-yl]pyridine (bpCOOEt2p) of formulas [Fe(bpCOOEt2p)2](ClO4)2·1.5MeNO2 (1), [Fe(bpCOOEt2p)2](ClO4)2·MeNO2 (2), and [Fe(bpCOOEt2p)2](ClO4)2·2MeNO2 (3) have been prepared and characterized. They show interesting spin-crossover (SCO) properties ranging from partial to complete thermal spin transitions and a light-induced excited spin-state trapping (LIESST) effect. In solvatomorph 2, a robust structure is formed with channels that enable the entrance or removal of solvent molecules by vapor diffusion without losing the crystallinity. Thus, solvent-exchanged samples [Fe(bpCOOEt2p)2](ClO4)2·MeNO2 (2·MeNO 2 ), [Fe(bpCOOEt2p)2](ClO4)2·MeCN (2·MeCN), [Fe(bpCOOEt2p)2](ClO4)2·0.5Me2CO (2·Me 2 CO), and [Fe(bpCOOEt2p)2](ClO4)2·MeCOOH (2·MeCOOH) were prepared by vapor diffusion of the solvents in a crystal of the compound previously heated to 400 K in a single-crystal to single-crystal (SCSC) fashion. Interestingly, this causes a change of spin state with a stabilization of the low-spin state in 2·Me 2 CO and the high-spin state in 2·MeCN. Therefore, the SCO properties of 2 can be tuned in a reversible way by exposure to different solvents.

Water-Induced Structural Evolution of LaTMSi Ternary Intermetallic Electrides

Ternary intermetallic electrides (LaTMSi) are a class of electride materials that show excellent catalytic performance in hydrogenation reactions due to their unique geometric and electronic structures. Compared with conventional electrides, such as C12A7: e–, LaTMSi show higher structural stability of bulk phase in air and water. However, their catalytic activities decrease gradually in reaction systems with H2O as the product. In the previous literatures, the deactivation behavior was attributed to the fact that H atoms enter into the LaTMSi lattice, occupy the electron sites, and lower the electron-donating ability. As a solution, the catalytic activities were supposed to be recovered by calcinating LaTMSi at high temperatures. Herein, under a H2O-containing atmosphere, TEM observations reveal that an amorphous shell with a thickness of ∼3 nm can form on the surface of the LaCu0.67Si1.33 phase even at room temperature. This amorphous layer is relatively stable at room temperature and can prevent the bulk phase from further structural evolution. However, the amorphous layer will undergo peeling off at a high temperature, thus resulting in a new catalytic active surface. Therefore, high-temperature calcination is an effective method to strip away the deactivated surface on LaTMSi which was caused by occasional exposures to H2O. However, for H2O-containing catalytic systems, frequently alternating reactions with H2O and calcination will lead to complete phase transition from LaTMSi to the corresponding oxides. Taking the LaCu0.67Si1.33 sample as an example, X-ray powder diffraction proves the formation of the CuO2 phase at 500 °C under a H2O atmosphere. Therefore, LaTMSi materials should not be applied as catalysts in H2O-containing systems. In addition, the facile H2O dissociation over the LaCu0.67Si1.33 phase is verified by using various experimental approaches (e.g., cyclic H218O pulse-TPD, high-temperature H218O pulse-TPSR, and IR) and theoretical calculations. Moreover, similar surface dissociation of H2O and phase transition are also observed over LaCoSi and LaNiSi ternary intermetallic electrides.

Study on the Performance of Flexible Memory Device Based on Antimony Film

Antimony films and devices based on polyether-ether-ketone (PEEK) flexible substrates were fabricated. After bending at different radii for 24 hours, the antimony film still achieved a complete phase transition after heating. When the bending cycle was more than 10000 times, the resistance difference between amorphous and crystalline states kept more than one order of magnitude. With the increase of bending times, grains tended to be refined, resulting in a wider band gap. The good ductility of antimony film made it have small resistance drift in tensile state. The reversible SET and RESET operations were realized in bending phase change memory device. Antimony films based on PEEK substrates had great potential applications in flexible phase change memories.

A Survey on the Understanding and Viewpoints of Renewable Energy among South African School Students

Renewable energy has become an essential component for the survival of human beings. This is because conventional energy supply is limited, nearing its limits, and or destroying our environment. The complete transition to renewable energy is a major approach to achieving sustainable and clean energy distribution progress in this ever-changing and demanding world. This research work investigates the knowledge of renewable energy among the youth and their understanding of sustainable energy prosperity towards meeting the future generation's energy needs. To achieve this, a set of questionnaires was developed to identify their knowledge of various renewable energy resources, energy aspects, applications, and the extent to which the current syllabus provides a well-developed background. They were administered to high school students in KwaZulu-Natal, Durban. The main findings of this investigation reveal that the students were most familiar with solar energy, which could be due to the increasing availability of solar panels across the nation. However, a lack of awareness and little understanding of geothermal energy was noted among the high school students. This indicates a poor future for its development. Furthermore, 86% of the students agreed that conventional energy sources would likely still be relied upon by a significant portion of the global population to meet daily energy needs. Therefore, the government must take swift action to address these issues, by promoting the deployment of renewable energy sources in schools.

Facile fabrication of Cu2O nanowire networks with large Seebeck coefficient for application in flexible thermoelectrics

The development of thermoelectrical nanowires and nanowire networks is crucial for application in self-powered electronics and flexible heat-to-power conversion devices. While Cu2O is a perspective p-type thermoelectric material, its research is mostly focused on the investigation of the properties of thin films or rigid cement composites with Cu2O powder fillers. In this work, Cu2O nanowire networks were fabricated by a simple technique and their thermoelectrical properties were investigated for the first time. Cu2O nanowire networks were obtained by annealing prefabricated CuO nanowire networks in an inert atmosphere at low pressure of 0.2 Torr. After annealing, nanowire networks showed a complete transition of CuO phase to Cu2O. Seebeck coefficient of Cu2O nanowire networks reached 2000 μV K−1. The estimated power factor of the Cu2O networks was found to be comparable with the Seebeck coefficient values of the state-of-the-art Cu2O thin films. The demonstrated in this work simple low-cost method for the fabrication of Cu2O nanowire networks illustrates the potential of this material for further applications in flexible thermoelectric devices.

Characterizing Hydrogen Storage Potential in U.S. Underground Gas Storage Facilities

AbstractUnderground hydrogen storage is a long‐duration energy storage option for a low‐carbon economy. Although research into the technical feasibility of underground hydrogen storage is ongoing, existing underground gas storage (UGS) facilities are appealing candidates for the technology because of their ability to store and deliver natural gas. We estimate that UGS facilities in the United States (U.S.) can store 327 TWh (9.8 MMT) of pure hydrogen. A complete transition to hydrogen storage would reduce the collective working‐gas energy of UGS facilities by ∼75%; however, most (73.2%) UGS facilities could maintain current energy demand using a 20% hydrogen‐natural gas blend. U.S. UGS facilities can buffer 23.9%–44.6% of the high and low hydrogen demand projected for 2050, respectively, which exceeds the current percentage of natural gas demand buffered by storage. Thus, transitioning UGS infrastructure to hydrogen could substantially reduce the number of new hydrogen storage facilities needed to support a hydrogen economy.