Specific Phase Research Articles

Chromatographic analysis of selected phytosterols from Cyathea and their characterization by in silico docking to potential therapeutic targets

Separation and quantification of lupeol, stigmasterol and swertiamarin in ethanolic extracts of selected Cyathea species have been developed using HPTLC and an attempt is made to explore the biopotential of phytochemicals against various proteins by computational analysis. Compounds were separated using the specific mobile phase and the developed plates were sprayed with respective spraying reagents. The 3D structure of the receptor proteins viz., 1VSN, 5BNQ, 6HN8, 7DN4 and 3TJU, and the 3D SDF structures of ligands like lupeol, stigmasterol and swertiamarin were retrieved from the Protein Data Bank (PDB) and NCBI-Pub Chem Compound database respectively. The Argus 4.0.1 is computer generated drug design screening software is employed to analyze the binding affinity of test compounds against the selected proteins in the form of E-values versus potential drug targets. The docking result was saved and visualized using Discovery Studio Visualizer. The terpenoid band with Rf value 0.79 depicted the presence of lupeol in C. gigantea (0.04%) and C. crinita (0.02%). The steroid band with Rf value 0.41 confirmed the presence of stigmasterol with varied frequency viz., C. nilgirensis (0.33%), C. gigantea (0.29%) and C. crinita (0.52%). Lupeol, stigmasterol and swertiamarin showed the interaction against the studied proteins viz., 1VSN, 5BNQ, 6HN8, 7DN4, 3TJU with varied energy values and interacting residues. The results of the virtual screening and molecular docking analysis suggest that the phytochemical compounds of Cyathea species viz., lupeol and stigmasterol were identified as possible lead molecules to fight against cancer and cytotoxicity.

The Great Instauration of the Eighteenth Century

This paper argues that there took place in the eighteenth century a specific, distinctive and essential phase in the emergence of modern science, a phase which can be characterised as “the Great Instauration” in that it witnessed the large-scale realisation of Francis Bacon’s earlier vision—albeit not, for the most part, through the specific means which Bacon had proposed. That claim is exemplified in three fields—the “physico-mathematical sciences,” chemistry and electricity—each of which yielded dramatic and permanent advances in knowledge; and an attempt is then made to render those advances intelligible in terms of specific social and technical themes. The paper proposes that the eighteenth-century Great Instauration arose from the development of an international natural-philosophical community, made possible by new institutions and especially by new publication media. And it suggests that what made this social development epistemologically fruitful was an inherently progressive process which had been anticipated by Bacon, namely what Sophie Weeks has called his “cybernetic” account of knowledge-making—the refinement of both questions and techniques in the light of Nature’s response to investigation.

Potential of phase change materials and their effective use in solar thermal applications: A critical review

• Different PCMs operated solar thermal systems are studied for performance enhancement. • Thermo-physical properties of a PCM are the key factors for its selection. • Complete charging & discharging of a PCM is essential for its complete life cycle. • Cost effectiveness is a major issue for adoption of a PCM for solar thermal systems. • Assessment of different PCMs is further required for their technology readiness level. Potential of the thermal energy storage materials especially phase change materials (PCM) is great support to the thermal systems for their performance enhancement especially for those systems which are operated on solar energy. In the present review study, some PCM operated solar thermal systems have been studied thoroughly to observe the real behavior of their improved performance by using a specific phase change material under variable ambient conditions. Apart from this, it has been observed that a complete charging and discharging cycle is necessary for a specified life cycle of the tested PCM. Heat transfer studies of different solar applications which operates on a variety of phase change materials shows that the performance improvement is fairly possible if the PCM is selected by considering the thermodynamic behavior of ‘to be used’ thermal system under a specific environment. It helps in selecting a suitable phase change material for a specific solar energy application. Results of the review study recommends some suitable phase change materials for solar cookers, solar stills, solar ponds, air heaters, PV systems and water heaters on the basis of their thermal characteristics specially operating temperature and their costs. A brief study on technology readiness level and levelized cost of storage shows the appropriateness of phase change materials for a wide adoption of them to be used in solar thermal applications. Overall, this study provides a very useful information about the thermal behavior, selection and the possible use of different phase change materials in solar energy systems, round the globe.

Solution characterization of a hyperbranched polysaccharide carbamate derivative and specific phase separation behavior due to chain branching.

A hyperbranched polymer consisting of rigid helical part chains was prepared as highly branched cyclic dextrin tris(phenylcarbamate) (HTPC) with the weight-average molar masses of 880 and 590 kg mol-1. Small-angle X-ray scattering (SAXS) measurement and viscometry were performed on the samples in good and poor solvents to determine the dimensional and hydrodynamic properties in solution. The HTPC molecule has a much more compact conformation than the linear chain with the same molar mass as expected for the hyperbranched architecture. While the corresponding linear polymer is soluble in methyl acetate (MEA) over a wide temperature range, HTPC is only soluble in the solvent at low temperatures. A typical LCST-type phase diagram was observed for the HTPC-MEA system, indicating that the interactions between the polymer segment of HTPC and the MEA molecules are substantially different from those of the linear chains. This is most likely due to the bending helical chains near the branching point of HTPC having different interactions with solvent molecules.

HOW THE LOWERING OF PRESSURE OR THE FORMATION OF ICE AFFECT THE FORMATION AND DISSOCIATION OF METHANE HYDRATES: VARIATIONS IN TERMS OF METASTABLE PHASE AND ANOMALOUS SELF-PRESERVATION

This research proposes the multiple and consecutive formation of methane hydrates with the same gas-water mixture and in a small-scale reactor. The scope consisted of better exploring how the variation of the initial pressure of the system modified the formation and dissociation processes. One of the most promising solutions for gas hydrates exploitation consists in the replacement of methane with carbon dioxide. This process inevitably requires the formation of CO<sub>2</sub> hydrates; thus, more details and analyses on the driving forces of the formation process are required in order to improve the overall replacement efficiency. Also, the competition with ice was analyzed. Nine tests were carried out in order to consider all these parameters. Each test was characterized thermodynamically and the time required to complete each specific phase of the process was measured. The tests were carried out at two different initial pressures: 60 and 50 bar, respectively. It was found that the main effect, associated with a lower initial pressure and/or with the presence of ice, is the stretching of the so-called metastable phase; since the local conditions became suitable for the formation of hydrates, the system required more time to begin in these latter cases. In the tests made at 60 bar, the delay in hydrate formation related to the metastable phase was equal to 0.73-1.04 h, while it ranged from 7.29 to 15.16 h in the tests made at 50 bar. Moreover, the results proved that the presence of ice hindered the formation process by reducing the heat transfer rate and by lowering the volume available for the process. Conversely, the begin of the dissociation phase was similar in all the experiments: the anomalous self-preservation, or the capability of the system to preserve itself even outside the hydrate stability zone was not observed, proving again that these limiting factors (lower initial pressure and ice formation) mainly affected the process during the formation phase.

THEORETICAL FRAMEWORK OF MANAGERIAL DECISIONMAKING DURING A CRISIS IN A DISCONTINUOUS BUSINESS ENVIRONMENT

Crisis are integral development components of all organizations which are functioning within a discontinuous environment. That is why management in organizations must become aware of the need for implementing the function of crisis management. Crisis management within organizations can be divided into two separate categories: active and reactive crisis management, depending on the specific crisis development phase. Crisis management existence will simplify the process of managerial decision-making in a crisis. It will also facilitate the prevention and recovery of crises. This paper explains the notion of crisis and its development phases, and indicates the need for crisis management within contemporary organizations. It analyses the problems of managerial decision-making during crisis periods from a certain point of view and it emphasises one approach to managerial decision-making.

Evidence-based improvement of gait in post-stroke patients following robot-assisted training: A systematic review.

The recovery of walking after stroke is a priority goal for recovering autonomy. In the last years robotic systems employed for Robotic Assisted Gait Training (RAGT) were developed. However, literature and clinical practice did not offer standardized RAGT protocol or pattern of evaluation scales. This systematic review aimed to summarize the available evidence on the use of RAGT in post-stroke, following the CICERONE Consensus indications. The literature search was conducted on Pubmed, Cochrane library and PEDro, including studies with the following criteria: 1) adult post-stroke survivors with gait disability in acute/subacute/chronic phase; 2) RAGT as intervention; 3) any comparators; 4) outcome regarding impairment, activity, and participation; 5) both primary studies and reviews. Sixty-one articles were selected. Data about characteristics of patients, level of disability, robotic devices used, RAGT protocols, outcome measures, and level of evidence were extracted. It is possible to identify robotic devices that are more suitable for specific phase disease and level of disability, but we identified significant variability in dose and protocols. RAGT as an add-on treatment seemed to be prevalent. Further studies are needed to investigate the outcomes achieved as a function of RAGT doses delivered.

Characterization and temporal dynamics of the intra- and extracellular environments of Lactiplantibacillus plantarum using multi-platform metabolomics

The characterization and temporal changes of intracellular and extracellular metabolome of Lactiplantibacillus plantarum under different growth times were studied using multi-platform metabolomics. A multi-platform approach consisting of both non-targeted profiling and targeted quantification has identified a total of 168 metabolites among which, 41 and 110 in the intra- and extracellular metabolomes were determined to be significantly different. We constructed an expanded metabolic pathway map that combines the amino acid, fatty acid, carbohydrate, purine, and pyrimidine pathways. Notably, we observed the dramatic increase of bioactive compound during growth such as indoles, phenylpropanoid, and hydroxy fatty acids produced by amino acid and fatty acid metabolism in the extracellular metabolome. Several B vitamins (pantothenic acid in intracellular metabolome and nicotinic acid, pyridoxine, and pyridoxal in extracellular metabolome) significantly increased in specific growth phase. In conclusion, this study has demonstrated the usefulness of a multi-platform approach in identifying a large pool of metabolites which, thus, has led, to a more robust understanding of the metabolic processes involved in the growth of L. plantarum HAC01. Furthermore, the change of discriminant metabolites with integrated metabolic pathway were revealed, which can be useful in identifying candidates for compound markers and postbiotic components for commercialization of probiotics formulation.

Prestimulus oscillatory brain activity interacts with evoked recurrent processing to facilitate conscious visual perception

We investigated whether prestimulus alpha-band oscillatory activity and stimulus-elicited recurrent processing interact to facilitate conscious visual perception. Participants tried to perceive a visual stimulus that was perceptually masked through object substitution masking (OSM). We showed that attenuated prestimulus alpha power was associated with greater negative-polarity stimulus-evoked ERP activity that resembled the visual awareness negativity (VAN), previously argued to reflect recurrent processing related to conscious perception. This effect, however, was not associated with better perception. Instead, when prestimulus alpha power was elevated, a preferred prestimulus alpha phase was associated with a greater VAN-like negativity, which was then associated with better cue perception. Cue perception was worse when prestimulus alpha power was elevated but the stimulus occurred at a nonoptimal prestimulus alpha phase and the VAN-like negativity was low. Our findings suggest that prestimulus alpha activity at a specific phase enables temporally selective recurrent processing that facilitates conscious perception in OSM.

On the interaction between Kelvin waves at different phase speeds and the background flow

AbstractKelvin waves have been theorized to be absorbed near the critical layer, where the phase speed matches the speed of the background flow. Nevertheless, it is not clear through observations how the structure of the Kelvin waves evolves near the critical layer or in response to vertical wind shear with or without a critical layer. A novel varying‐coefficient regression technique that has been used to study evolving relationships across the seasonal cycle is used to capture how the wavelet‐filtered waves with a specific phase speed appear in different background winds or vertical shear regimes or a combination of both. Results show a relaxation of the in‐phase relationship between the zonal wind and geopotential height anomalies at slower Doppler‐shifted speeds, followed by the appearance of the Gill pattern at further reduction of the Doppler‐shifted speed, demonstrating a lack of dominant Kelvin wave signals in those conditions. We define the “observed critical layer” as the layer where the signals consistent with Kelvin waves fade away irrespective of the value of the Doppler‐shifted speed, which reduces to zero at the “theoretical critical layer.” Results show that wave structures consistent with Kelvin waves are not present at the top of layer with westerly vertical shear of the zonal wind, yet they exist during the easterly vertical shear of the zonal wind. The second part of the paper presents the dispersion equation of the Kelvin wave under vertical wind shear. The phase speed of the Kelvin wave proportionally increases with the Richardson number (and hence proportionally decreases with the vertical wind shear). The Richardson number varies with the vertical resolution of the data used, adding uncertainty to the calculated phase speed of the wave in the presence of vertical wind shear.

Preliminary Study on Red Wine Aroma: The Volatile Profiles of Six Grape Cultivars in Different Vinification Phases

Consumers’ appreciation of wines is mainly driven by their aroma, which is the most important organoleptic characteristic and key attribute. The volatile bouquet derives from the grape berries and from the processing phases of vinification. In the present study, the volatile emission of six grapevine cultivars has been analysed through four phases of vinification: the headspaces of crushed grapes, fermented must, new wine (2 months old), and wine (7 months old) have been sampled and analysed. This showed the evolution of the volatile compounds based on the chemical and mechanical processes involved in the specific vinification phase. Chemometric tools (hierarchical cluster and principal component analyses) have revealed that samples gather in statistical groups based on the vinification phase they belong to, though they maintain an aroma composition that is typical of the grape berry of origin.

Phase-adaptive brain stimulation of striatal D1 medium spiny neurons in dopamine-depleted mice

Brain rhythms are strongly linked with behavior, and abnormal rhythms can signify pathophysiology. For instance, the basal ganglia exhibit a wide range of low-frequency oscillations during movement, but pathological “beta” rhythms at ~ 20 Hz have been observed in Parkinson’s disease (PD) and in PD animal models. All brain rhythms have a frequency, which describes how often they oscillate, and a phase, which describes the precise time that peaks and troughs of brain rhythms occur. Although frequency has been extensively studied, the relevance of phase is unknown, in part because it is difficult to causally manipulate the instantaneous phase of ongoing brain rhythms. Here, we developed a phase-adaptive, real-time, closed-loop algorithm to deliver optogenetic stimulation at a specific phase with millisecond latency. We combined this Phase-Adaptive Brain STimulation (PABST) approach with cell-type-specific optogenetic methods to stimulate basal ganglia networks in dopamine-depleted mice that model motor aspects of human PD. We focused on striatal medium spiny neurons expressing D1-type dopamine receptors because these neurons can facilitate movement. We report three main results. First, we found that our approach delivered PABST within system latencies of 13 ms. Second, we report that closed-loop stimulation powerfully influenced the spike-field coherence of local brain rhythms within the dorsal striatum. Finally, we found that both 4 Hz PABST and 20 Hz PABST improved movement speed, but we found differences between phase only with 4 Hz PABST. These data provide causal evidence that phase is relevant for brain stimulation, which will allow for more precise, targeted, and individualized brain stimulation. Our findings are applicable to a broad range of preclinical brain stimulation approaches and could also inform circuit-specific neuromodulation treatments for human brain disease.

Growth Phase Influence the Gene Expression and Metabolite Production Related to Indole-3-Acetic Acid (IAA) Biosynthesis by Serratia plymuthica UBCF_13.

<b>Background and Objective:</b> The optimization of the indole-3-acetic acid (IAA) producing capability of <i>Serratia plymuthica</i> UBCF_13 has been intensively studied. This work tried to reveal the effect of growth phases on IAA production, gene expression and metabolite synthesis related to the IAA biosynthesis pathway. <b>Materials and Methods:</b> The growth curve and IAA production were measured every 3 hrs. The putative IAA biosynthesis pathway was investigated based on the UBCF_13 genome. To identify the possible pathway of IAA biosynthesis in UBCF_13, we applied the Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) and High-Performance Liquid Chromatography (HPLC) analysis to measure the transcript levels of each gene and indole metabolite production based on tryptophan treatment at different times of incubation. <b>Results:</b> The optimal IAA production on colorimetric assay was at 9 hrs of incubation (initial stationary phase). The level expression of <i>puuC</i>, <i>DDC</i>, <i>oxdA</i>, <i>amiE</i>, <i>nthA</i> and <i>nthB</i> have been upregulated maximum in 3 hrs of culture time (lag phase), except <i>tyrB</i> and <i>ipdC</i>. The highest transcript level of the genes was found in nitrile hydratase genes (<i>nthA</i> and <i>nthB</i>) and indole-3- acetamide (IAM) has been detected as the only intermediate in the crude extract of UBCF_13 thus the IAM pathway may be used to produce IAA. The maximum IAA production on HPLC analysis was found at 21 hrs of incubation (late stationary phase). <b>Conclusion:</b> This study gives a new insight that the best time to measure gene expression and intermediates related to the IAA biosynthetic pathway in bacteria was found at a specific growth phase.

Short report: A co-designed psychoeducation for older autistic adults-a multiple case study.

After receiving an autism diagnosis by a clinician, psychoeducation (i.e. information regarding autism) is often offered. However, older autistic adults (55+ years) may need specific information about the challenges they face in daily life as they are in a specific life phase. A psychoeducation program for this specific age group does not exist yet. We first developed such a program together with autistic adults and clinicians working with autistic people, after which we tested the program with nine autistic adults (56-73 years) and someone close to them (so-called proxy). Before testing the program, we determined together with autistic older adults what they thought should be the outcome of this intervention in order to state whether it was, indeed, a useful intervention. Earlier studies found that autistic people often think differently about their own autistic characteristics than their proxy. A reduction of this difference could increase mutual understanding. Therefore, the main hypothesis was that the program would decrease this difference with respect to autistic characteristics and cognitive challenges (e.g. memory problems). Another hypothesis was that the program would have a positive impact on a series of other factors, such as self-esteem. The results showed that the program did neither decrease the difference in insight nor the other tested factors. Nonetheless, we believe it is important to keep on working on a psychoeducation program for older autistic adults, because participants informed us the program had still helped them in certain ways and they gave helpful feedback for improvements of the program.

Experimental research on the variation of microclimate factors in healing tunnels designed for grafted vegetable seedlings

During the healing process, the scion and the rootstock must establish vascular connection, which is considered the most critical process in the production of grafted vegetables. Therefore, the healing process must be carried out in a monitored and controlled environment, in special healing areas, where parameters characterizing the microclimate must be maintained at the optimal values, ideally with great precision. The main objective of the current experiment was to analyse the variation of microclimate factors in the curing and acclimatization chambers of grafted vegetable seedlings during specific technological phase. The measurements of different abiotic factors such as relative humidity, temperature, light radiation intensity and CO2 concentration were carried out inside an experimental research healing tunnel situated inside a greenhouse. After grafting, the grafted seedlings were placed in specialized enclosures for their healing and the results shown that variations of the plants density and determined microclimate factors significantly affect the quality of seedlings. Because the stages of obtaining grafted seedlings are relatively short, fluctuations in environmental factors can have dramatic effects on the quality and quantity of grafted seedling production. Such a study of the prediction of microclimate factors must lead to the development of a versatile prediction model that can be used in any climatic conditions, at any time of the year and in any geographical location.

Inferring oscillator’s phase and amplitude response from a scalar signal exploiting test stimulation

The phase sensitivity curve or phase response curve (PRC) quantifies the oscillator’s reaction to stimulation at a specific phase and is a primary characteristic of a self-sustained oscillatory unit. Knowledge of this curve yields a phase dynamics description of the oscillator for arbitrary weak forcing. Similar, though much less studied characteristic, is the amplitude response that can be defined either using an ad hoc approach to amplitude estimation or via the isostable variables. Here, we discuss the problem of the phase and amplitude response inference from observations using test stimulation. Although PRC determination for noise-free neuronal-like oscillators perturbed by narrow pulses is a well-known task, the general case remains a challenging problem. Even more challenging is the inference of the amplitude response. This characteristic is crucial, e.g. for controlling the amplitude of the collective mode in a network of interacting units—a task relevant to neuroscience. Here, we compare the performance of different techniques suitable for inferring the phase and amplitude response, particularly with application to macroscopic oscillators. We suggest improvements to these techniques, e.g. demonstrating how to obtain the PRC in case of stimuli of arbitrary shape. Our main result is a novel technique denoted by IPID-1, based on the direct reconstruction of the Winfree equation and the analogous first-order equation for isostable dynamics. The technique works for signals with or without well-pronounced marker events and pulses of arbitrary shape; in particular, we consider charge-balanced pulses typical in neuroscience applications. Moreover, this technique is superior for noisy and high-dimensional systems. Additionally, we describe an error measure that can be computed solely from data and complements any inference technique.

Size Reduction and Performance Enhancement of Coplanar-Waveguide Resonators for Surface Plasmonic Applications

Coplanar waveguide (CPW) is partially integrated with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> -strip TLs at critical areas with locally strong electromagnetic field confinement. The new integration is shown to impact the propagation constant of the structure.The impacts of the added <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> -strip TL are theoretically discussed on a loaded CPW using the incident-reflected wave concept. It is mathematically shown that a specific phase is added to the phase of conventional CPWs by the proposed modification. The added phase is then used for physical size reduction and performance enhancement of the structure. Considering the propagation manipulation of the CPWs, the modified structure is researched as a unit cell for spoof surface plasmon polariton (SSPP).

Highly Efficient Decoupled Triple‐Channel OAM Generation with a Single‐Layer Shared Aperture Reflective Metasurface

AbstractMetasurface is extensively studied for generating multicharacteristic orbital angular momentum (OAM) beams. However, designing a highly integrated and independent polarization‐frequency multiplexing metasurface for efficient multiscenario OAM‐related applications is still a challenge. Here, a triple‐band single‐layer shared aperture reflective metasurface for triple‐polarization channels independent OAM modulations is proposed. The specific frequency quantitative customization resonance phase and quasi‐static geometric phase are utilized to manipulate the dual‐band (Ku‐ and K‐band) orthogonal linearly polarized (LP) channel and C&amp;X‐band right‐handed circularly polarized (RHCP) channel. An isolation ring is introduced for eliminating the strong coupling between the structurally compatible RHCP and orthogonal‐LP subunits in a shared aperture meta‐atom. It is revealed that the isolation ring not only helps realize efficient multipolarization, multiband, and multimode OAM generation, but also expands the operation bandwidth of the RHCP channel OAM. A proof‐of‐concept prototype of the designed metasurface is constructed to verify the methodology and the experimental results are in excellent agreement with simulations. The proposed independent OAM modulation scheme for extending the functionality of metasurface offers a novel route to realize multipolarization and multiband OAM beams with high isolation, which may have potential applications in OAM‐based multichannel multiplexing communications.

Heterogeneity-induced synchronization in delay-coupled electronic oscillators.

We study synchronization in networks of delay-coupled electronic oscillators, so-called phase-locked loops (PLLs). Using a phase-model description, we study the collective dynamics of mutually coupled PLLs and report the phenomenon of heterogeneity-induced synchronization. This phenomenon refers to the observation that heterogeneity in the system's parameters can induce synchronization by stabilizing the states which are unstable without such heterogeneity. In systems where component heterogeneity can be tuned and controlled, we show how the complex collective self-organized dynamics can be guided towards synchronized states with specific operational frequencies and phase relations. This is of importance for the technical applicability of self-organized dynamics. In electrical engineering, for example, where components can be strongly heterogeneous, our theoretical framework can inform the design process for networks of spatially distributed PLLs. The results presented here are also useful in understanding the collective dynamics in ensembles of phase oscillators with time-delayed interactions, inertia, and heterogeneity.

Controlling the Crystal Phase Structure of WO3 Nanosheet-Based Hierarchical Spheres for Enhanced Gas Sensing Performance

The pursuit of high performance is the eternal theme in gas sensor research. Because of the complexity of the response and recovery processes, the selective detection, high response, rapid response, and recovery remain challenging in the atmospheric environment. In this paper, WO3 hierarchical spheres (WO3 HS) with different crystalline phase ratios are successfully synthesized to evaluate the relationship between the phase structure and gas-sensitive properties. The as-prepared WO3-2 HS samples achieve superior gas sensing characteristics including high response (S = 24.2) and fast response and recovery speed (1 and 19 s) to 100 ppm acetone at 300 °C. The superior acetone sensing performance probably originates from the regulation of the phase ratios of nanosheet-based WO3. With the decrease of orthorhombic phase and the increase of monoclinic phase, the specificity detection to acetone is increased significantly. The reasons for such a huge selectivity change are discussed in detail. From the perspective of reaction kinetics, we also compare the contributions of specific surface area and crystalline phase impacting the gas sensing performance.