Role of acemannan and pectic polysaccharides in saline-water stress tolerance of Aloe vera (Aloe barbadensis Miller) plant.

This study investigates the impact of water and salinity stress on Aloe vera, focusing on the role of Aloe vera polysaccharides in mitigating these stresses. Pectins and acemannan were the most affected polymers. Low soil moisture and high salinity (NaCl 80 mM) increased pectic substances, altering rhamnogalacturonan type I in Aloe vera gel. Aloe vera pectins maintained a consistent 60 % methyl-esterification regardless of conditions. Interestingly, acemannan content rose with salinity, particularly under low moisture, accompanied by 90 to 150 % acetylation increase. These changes improved the functionality of Aloe vera polysaccharides: pectins increased cell wall reinforcement and interactions, while highly acetylated acemannan retained water for sustained plant functions. This study highlights the crucial role of Aloe vera polysaccharides in enhancing plant resilience to water and salinity stress, leading to improved functional properties.

Spatial Photo-Patterning of Nematic Liquid Crystal Pretilt and its Application in Fabricating Flat Gradient-Index Lenses.

Liquid crystals offer a dynamic platform for developing advanced photonics and soft actuation systems due to their unique and facile tunability and reconfigurability. Achieving precise spatial patterning of the liquid crystal alignment is critical to developing electro-optical devices, programmable origami, directed colloidal assembly, and controlling active matter. Here, a simple method is demonstrated to achieve continuous 3D control of the directions of liquid crystal mesogens using a two-step photo-exposure process. In the first step, polarized light sets the orientation in the plane of confining substrates; the second step uses unpolarized light of a prescribed dose to set the out-of-plane orientation. The method enables smoothly varying orientational patterns with sub-micrometer precision. As a demonstration, the setup is used to create gradient-index lenses with parabolic refractive index profiles that remain stable without external electric fields. The lenses' focal length and sensitivity to light polarization are characterized through experimental and numerical methods. The findings pave the way for developing next-generation photonic devices and actuated materials, with potential applications in molecular self-assembly, re-configurable optics, and responsive matter.

Evaluation of Acemannan in Different Commercial Beverages Containing Aloe Vera (Aloe barbadensis Miller) Gel.

Aloe vera (Aloe barbadensis Miller) gel is a frequently used ingredient in many food pro-ducts, particularly beverages, due to its reported health benefits. Studies have identified acemannan, a polysaccharide rich in mannose units which are partially or fully acetylated, as the primary bioactive compound in Aloe vera gel. The acemannan content and its degree of acetylation (DA) were measured in 15 different commercial beverages containing Aloe vera at varying concentrations (from 30% to 99.8%) as listed on the label. Other biopolymers such as pectins, hemicelluloses, and cellulose were also evaluated. Flavoured beverages (seven samples labelled as containing from 30% to 77% Aloe vera) presented low levels of acemannan (<30 mg/100 g of fresh sample) and were fully deacetylated in most cases. These samples had high levels of other polymers such as pectins, hemicelluloses, and cellulose, likely due to the addition of fruit juices for flavour. Unflavoured beverages (eight samples, with Aloe vera concentrations above 99% according to their labels) had variable levels of acemannan, with only three containing more than 160 mg/100 g of fresh sample. In fact, four samples had less than 35 mg acemannan/100 g of fresh sample. DA levels in all but one sample were lower than 35%, possibly due to processing techniques such as pasteurization causing degradation and deacetylation of the acemannan polymer. Legislation regarding Aloe vera products is limited, and manufacturers are not required to disclose the presence or quality of bioactive compounds in their products, leaving consumers uncertain about the true properties of the products they purchase.

Migration and division in cell monolayers on substrates with topological defects.

Collective movement and organization of cell monolayers are important for wound healing and tissue development. Recent experiments highlighted the importance of liquid crystal order within these layers, suggesting that +1 topological defects have a role in organizing tissue morphogenesis. We study fibroblast organization, motion, and proliferation on a substrate with micron-sized ridges that induce +1 and -1 topological defects using simulation and experiment. We model cells as self-propelled deformable ellipses that interact via a Gay-Berne potential. Unlike earlier work on other cell types, we see that density variation near defects is not explained by collective migration. We propose instead that fibroblasts have different division rates depending on their area and aspect ratio. This model captures key features of our previous experiments: the alignment quality worsens at high cell density and, at the center of the +1 defects, cells can adopt either highly anisotropic or primarily isotropic morphologies. Experiments performed with different ridge heights confirm a prediction of this model: Suppressing migration across ridges promotes higher cell density at the +1 defect. Our work enables a mechanism for tissue patterning using topological defects without relying on cell migration.

Tunable three-dimensional architecture of nematic disclination lines.

Disclination lines play a key role in many physical processes, from the fracture of materials to the formation of the early universe. Achieving versatile control over disclinations is key to developing novel electro-optical devices, programmable origami, directed colloidal assembly, and controlling active matter. Here, we introduce a theoretical framework to tailor three-dimensional disclination architecture in nematic liquid crystals experimentally. We produce quantitative predictions for the connectivity and shape of disclination lines found in nematics confined between two thinly spaced glass substrates with strong patterned planar anchoring. By drawing an analogy between nematic liquid crystals and magnetostatics, we find that i) disclination lines connect defects with the same topological charge on opposite surfaces and ii) disclination lines are attracted to regions of the highest twist. Using polarized light to pattern the in-plane alignment of liquid crystal molecules, we test these predictions experimentally and identify critical parameters that tune the disclination lines' curvature. We verify our predictions with computer simulations and find nondimensional parameters enabling us to match experiments and simulations at different length scales. Our work provides a powerful method to understand and practically control defect lines in nematic liquid crystals.

Reversible Microscale Assembly of Nanoparticles Driven by the Phase Transition of a Thermotropic Liquid Crystal.

The arrangement of nanoscale building blocks into patterns with microscale periodicity is challenging to achieve via self-assembly processes. Here, we report on the phase-transition-driven collective assembly of gold nanoparticles in a thermotropic liquid crystal. A temperature-induced transition from the isotropic to the nematic phase under anchoring-driven planar alignment leads to the assembly of individual nanometer-sized particles into arrays of micrometer-sized agglomerates, whose size and characteristic spacing can be tuned by varying the cooling rate. Phase field simulations coupling the conserved and nonconserved order parameters exhibit a similar evolution of the morphology as the experimental observations. This fully reversible process offers control over structural order on the microscopic level and is an interesting model system for the programmable and reconfigurable patterning of nanocomposites with access to micrometer-sized periodicities.

A New Functional Food Ingredient Obtained from Aloe ferox by Spray Drying.

Aloe mucilages of Aloe ferox (A. ferox) and Aloe vera (A. vera) were spray-dried (SD) at 150, 160 and 170 °C. Polysaccharide composition, total phenolic compounds (TPC), antioxidant capacity and functional properties (FP) were determined. A. ferox polysaccharides were comprised mainly of mannose, accounting for >70% of SD aloe mucilages; similar results were observed for A. vera. Further, an acetylated mannan with a degree of acetylation >90% was detected in A. ferox by 1H NMR and FTIR. SD increased the TPC as well as the antioxidant capacity of A. ferox measured by both ABTS and DPPH methods, in particular by ~30%, ~28% and ~35%, respectively, whereas in A. vera, the antioxidant capacity measured by ABTS was reduced (>20%) as a consequence of SD. Further, FP, such as swelling, increased around 25% when A. ferox was spray-dried at 160 °C, while water retention and fat adsorption capacities exhibited lower values when the drying temperature increased. The occurrence of an acetylated mannan with a high degree of acetylation, together with the enhanced antioxidant capacity, suggests that SD A. ferox could be a valuable alternative raw material for the development of new functional food ingredients based on Aloe plants.

Emergence and stabilization of transient twisted defect structures in confined achiral liquid crystals at a phase transition.

Spontaneous emergence of chirality is a pervasive theme in soft matter. We report a transient twist forming in achiral nematic liquid crystals confined to a capillary tube with square cross section. At the smectic-nematic phase transition, intertwined disclination line pairs are observed with both helical and kinked lozenge-like contours, configurations that we promote through capillary cross-section geometry and stabilize using fluorescent amphiphilic molecules. The observed texture is similar to that found in "exotic" materials such as chromonics, but it is here observed in common thermotropic nematics upon heating from the smectic into the nematic phase. Numerical modeling further reveals that the disclinations may possess winding characters that are intermediate between wedge and twist, and that vary along the defect contours. In our experiments, we utilize a phase transition to generate otherwise elusive defect structures in common liquid crystal materials.

Topological defects of integer charge in cell monolayers.

Many cell types spontaneously order like nematic liquid crystals, and, as such, they form topological defects, which influence the cell organization. While defects with topological charge ±1/2 are common in cell monolayers, defects with charge ±1, which are thought to be relevant in the formation of protrusions in living systems, are more elusive. We use topographical patterns to impose topological charge of ±1 in controlled locations in cell monolayers. We study two types of cells, 3T6 fibroblasts and EpH-4 epithelial cells, and we compare their behavior on such patterns, characterizing the degree of alignment, the cell density near the defects, and their behavior at the defect core. We observe density variation in the 3T6 monolayers near both types of defects over the same length-scale. By choosing appropriate geometrical parameters of our topographical features, we identify a new behavior of 3T6 cells near the defects with topological charge +1, leading to a change in the cells' preferred shape. Our strategy allows a fine control of cell alignment near defects as a platform to study liquid crystalline properties of cells.

The 50 most-cited articles on clear aligner treatment: A bibliometric and visualized analysis.

INTRODUCTION: Research on clear aligner treatment (CAT) has increased in recent years. In this study, we aimed to perform a bibliometric and visualized analysis to identify and critically assess the 50 most highly cited articles on CAT. METHODS: Web of Science was selected as a data source and consulted until March 2020 to identify all articles potentially relevant to the analysis. All the eligible articles were collected until 50 manuscripts were listed. Article-based parameters, journal-based parameters, and author-based parameters were registered to perform the bibliometric analysis. Keywords were automatically harvested from the selected articles to implement the visualized analysis. RESULTS: The search identified a total of 378 articles; the total number of citations of the selected articles varied from 15 to 112. The average number of citations per year varied from 1.15 to 13.83. The predominant study design was clinical (31.7%). Over the 15 journals in which the most cited articles were published, the American Journal of Orthodontics and Dentofacial Orthopedics published the majority of those included in the list (14) and also received the greatest number of citations (671). A total of 195 authors contributed to the 50 most cited articles; a significant portion of them (26) were unaffiliated with academic institutions. A total of 184 keywords were gathered from the article list. CONCLUSIONS: The number of citations on CAT is expected to grow steadily in parallel with the rising number of research projects. The present work identifies the most influential articles on CAT and their characteristics, placing emphasis on the journals, the authors, and the topics addressed.

Chiral Liquid Crystal Lenses Confined in Microchannels.

It is known that the liquid crystalline smectic-A phase has geometric defects, called focal conic domains, which can be used as gradient-index microlenses. Cholesteric (chiral nematic) phases also have topological defects with a central symmetry and a singularity at their center. We explore a weakly chiral system in which both types of defects can be present in the same material at different temperatures, and with this strategy we create lenses whose focal length is tunable with temperature. We measure the focal length of the tunable lenses, and we investigate the behavior of the defects near the phase transition. We identify the experimental conditions that make the simultaneous presence of the smectic focal conic domains and the circular cholesteric domains possible, such as the concentration of chiral dopant and the rate of heating and cooling. The transformation of focal conic domains into circular cholesteric domains is a new example of memory at the phase transition between smectic-A and nematic liquid crystals.

Shape-Memory Polymers in Dentistry: Systematic Review and Patent Landscape Report.

OBJECTIVE: To perform a systematic review (SR) of existing literature and a patent landscape report (PLR) regarding the potential applications of shape-memory polymers (SMPs) in dentistry. SEARCH STRATEGY: Clinical and Biomedical online databases (Pubmed, Medline via Embase, Scopus, LILACS, Web of Science, Cochrane Library), Materials Science and Engineering databases (IEEE Explore, Compendex, Proquest), Material Science and Chemical database (Reaxys) so as Patents databases (Questel-Orbit, Espacenet, Patentscope) were consulted as recently as January 2019 to identify all papers and patents potentially relevant to the review. The reference lists of all eligible studies were hand searched for additional published work. RESULTS: After duplicate selection and extraction procedures, 6 relevant full-text articles from the initial 302 and 45 relevant patents from 497 were selected. A modified Consolidated Standards of Reporting Trials (CONSORT) checklist of 14 items for reporting pre-clinical in-vitro studies was used to rate the methodological quality of the selected papers. The overall quality was judged low. CONCLUSIONS: Despite the great potential and versatility of SMPs, it was not possible to draw evidence-based conclusions supporting their immediate employment in clinical dentistry. This was due to the weak design and a limited number of studies included within this review and reflects the fact that additional research is mandatory to determine whether or not the use of SMPs in dentistry could be effective. Nevertheless, the qualitative analysis of selected papers and patents indicate that SMPs are promising materials in dentistry because of their programmable physical properties. These findings suggest the importance of furtherly pursuing this line of research.

Energy dispersion spectroscopy analysis on failed implants: a preliminary survey.

BACKGROUND: Peri-implantitis or implant infection is a biologic complication involving soft and hard tissues around implants. The prevalence of the disease was recently estimated between 12% and 14% according to studies dealing with the private practice, which is also consistent with university statistics. Different methods were presented to minimize or even to remove biofilm from contaminated surfaces completely. Chemical and air-abrasive treatments have been shown to be able to disrupt biofilm. Chemical cleaning solution in combination with mechanical debridement is ineffective to eliminate bacterial biofilm. Lasers and photodynamic therapy presented inconsistent results. Interestingly, implantoplasty remains a preferred way to remove infected contaminants. When re-osseointegration of these treated contaminated implant surfaces was assessed, the quality of the implant surface after decontamination dictates the outcome. No matter the type of intervention implemented to counteract peri-implantitis, implant failure sometimes remains an unavoidable outcome. In this in-vitro report, the authors propose an automated EDS analysis of the whole dental implant surface to determine the percentage directly involved by the bacterial biofilm on failed fixtures. METHODS: Samples morphology was studied using a Scanning Electron Microscope (SEM, Zeiss Evo 50 XVP with LaB6 source). The instrument is endowed with detectors for secondary and backscattered electrons collection, as well as energy dispersion spectroscopy (EDS) analyzer for elemental analysis. All the materials were observed using 10kV of voltage. Samples, soon after being collected and fixed in 4% paraformaldehyde, were covered with a golden layer of about 10 nm in order to avoid charge accumulation during SEM-EDS analysis. Automated EDS mapping was obtained on the entire surface. RESULTS: On the samples analyzed (N.=10), the mean surface covered by bacterial biofilm was 79.3±7.6% (Mean±95% CI) based on the percentage of titanium, oxygen, and phosphorous. As a control, direct observation of the samples was also performed owing to SEM images finding an optimal correlation between the automatic EDS mapping and human-driven quantification of the bacterial biofilm. CONCLUSIONS: Based on these preliminary data, EDS automatic mapping may be considered an exciting method to analyze failed implants. Furthermore, the possible future applications in this field, once the bacteria have been identified, could involve a more specific treatment with the aim of remove infected contaminants on the implant surfaces.

Deck the Walls with Anisotropic Colloids in Nematic Liquid Crystals.

Nematic liquid crystals (NLCs) offer remarkable opportunities to direct colloids to form complex structures. The elastic energy field that dictates colloid interactions is determined by the NLC director field, which is sensitive to and can be controlled by boundaries including vessel walls and colloid surfaces. By molding the director field via liquid-crystal alignment on these surfaces, elastic energy landscapes can be defined to drive structure formation. We focus on colloids in otherwise defect-free director fields formed near undulating walls. Colloids can be driven along prescribed paths and directed to well-defined docking sites on such wavy boundaries. Colloids that impose strong alignment generate topologically required companion defects. Configurations for homeotropic colloids include a dipolar structure formed by the colloid and its companion hedgehog defect or a quadrupolar structure formed by the colloid and its companion Saturn ring. Adjacent to wavy walls with wavelengths larger than the colloid diameter, spherical particles are attracted to locations along the wall with distortions in the nematic director field that complement those from the colloid. This is the basis of lock-and-key interactions. Here, we study ellipsoidal colloids with homeotropic anchoring near complex undulating walls. The walls impose distortions that decay with distance from the wall to a uniform director in the far field. Ellipsoids form dipolar defect configurations with the colloid's major axis aligned with the far field director. Two distinct quadrupolar defect structures also form, stabilized by confinement; these include the Saturn I configuration with the ellipsoid's major axis aligned with the far field director and the Saturn II configuration with the major axis perpendicular to the far field director. The ellipsoid orientation varies only weakly in bulk and near undulating walls. All configurations are attracted to walls with long, shallow waves. However, for walls with wavelengths that are small compared to the colloid length, Saturn II is repelled, allowing selective docking of aligned objects. Deep, narrow wells prompt the insertion of a vertical ellipsoid. By introducing an opening at the bottom of such a deep well, we study colloids within pores that connect two domains. Ellipsoids with different aspect ratios find different equilibrium positions. An ellipsoid of the right dimension and aspect ratio can plug the pore, creating a class of 2D selective membranes.

Colloids in confined liquid crystals: a plot twist in the lock-and-key mechanism.

By confining soft materials within tailored boundaries it is possible to design energy landscapes to address and control colloidal dynamics. This provides unique opportunities to create reconfigurable, hierarchically organized structures, a leading challenge in materials science. Example soft matter systems include liquid crystals. For instance, when nematic liquid crystals (NLCs) are confined in a vessel with undulated boundaries, bend and splay distortions can be used to position particles. Here we confine this system in a twist cell. We also study cholesteric liquid crystals, which have an "intrinsic" twist distortion which adds to the ones imposed by the solid boundaries. The cholesteric pitch competes with the other length scales in the system (colloid radius, vessel thickness, wavelength of boundary undulations), enriching the possible configurations. Depending on the pitch-to-radius and pitch-to-thickness ratios the interaction can be attractive or repulsive. By tuning the pitch (i.e. changing the concentration of the chiral dopant), it is possible to selectively promote or inhibit particle trapping at the docking sites.

Agitated depression in bipolar disorder.

OBJECTIVES: It has been suggested that agitated depression (AD) is a common, severe feature in bipolar disorder. We aimed to estimate the prevalence of AD and investigate whether presence of AD was associated with episodic and lifetime clinical features in a large well-characterized bipolar disorder sample. METHOD: The prevalence of agitation, based on semi-structured interview and medical case-notes, in the most severe depressive episode was estimated in 2925 individuals with DSM-IV bipolar disorder recruited into the UK Bipolar Disorder Research Network. Predictors of agitation were ascertained using symptoms within the same episode and lifetime clinical features using multivariate models. RESULTS: 32.3% (n = 946) experienced agitation during the worst depressive episode. Within the same episode, significant predictors of presence of agitation were: insomnia (OR 2.119, P < 0.001), poor concentration (OR 1.966, P = 0.027), decreased libido (OR 1.960, P < 0.001), suicidal ideation (OR 1.861, P < 0.001), slowed activity (OR 1.504, P = 0.001), and poor appetite (OR 1.297, P = 0.029). Over the lifetime illness course, co-morbid panic disorder (OR 2.000, P < 0.001), suicide attempt (OR 1.399, P = 0.007), and dysphoric mania (OR 1.354, P = 0.017) were significantly associated with AD. CONCLUSIONS: Agitation accompanied bipolar depression in at least one-third of cases in our sample and was associated with concurrent somatic depressive symptoms, which are also common features of mixed manic states. Furthermore, AD in our sample was associated with lifetime experience of mixed mania, in addition to severe lifetime illness course including comorbid panic disorder and suicidal behavior. Our results have implications for the diagnosis and treatment of agitated features in bipolar depression.

Tunable colloid trajectories in nematic liquid crystals near wavy walls.

The ability to dictate the motion of microscopic objects is an important challenge in fields ranging from materials science to biology. Field-directed assembly drives microparticles along paths defined by energy gradients. Nematic liquid crystals, consisting of rod-like molecules, provide new opportunities in this domain. Deviations of nematic liquid crystal molecules from uniform orientation cost elastic energy, and such deviations can be molded by bounding vessel shape. Here, by placing a wavy wall in a nematic liquid crystal, we impose alternating splay and bend distortions, and define a smoothly varying elastic energy field. A microparticle in this field displays a rich set of behaviors, as this system has multiple stable states, repulsive and attractive loci, and interaction strengths that can be tuned to allow reconfigurable states. Microparticles can transition between defect configurations, move along distinct paths, and select sites for preferred docking. Such tailored landscapes have promise in reconfigurable systems and in microrobotics applications.

New Perspectives in the Adaptive Assessment of Depression: The ATS-PD Version of the QuEDS.

Measurement is a crucial issue in psychological assessment. In this paper a contribution to this task is provided by means of the implementation of an adaptive algorithm for the assessment of depression. More specifically, the Adaptive Testing System for Psychological Disorders (ATS-PD) version of the Qualitative-Quantitative Evaluation of Depressive Symptomatology questionnaire (QuEDS) is introduced. Such implementation refers to the theoretical background of Formal Psychological Assessment (FPA) with respect to both its deterministic and probabilistic issues. Three models (one for each sub-scale of the QuEDS) are fitted on a sample of 383 individuals. The obtained estimates are then used to calibrate the adaptive procedure whose performance is tested in terms of both efficiency and accuracy by means of a simulation study. Results indicate that the ATS-PD version of the QuEDS allows for both obtaining an accurate description of the patient in terms of symptomatology, and reducing the number of items asked by 40%. Further developments of the adaptive procedure are then discussed.

Compositional and Structural Features of the Main Bioactive Polysaccharides Present in the Aloe vera Plant.

Aloe vera (A. barbadensis Miller) is probably one of the most popular plants, widely studied because of numerous properties associated with the polysaccharides present in its gel. In particular, two main types of bioactive polysaccharides can be distinguished in the A. vera gel: an acetylated mannose-rich polymer that functions as storage polysaccharide, and a galacturonic acid-rich polymer as the main component comprising the cell walls of the parenchymatous tissue. Interestingly, most of the beneficial properties related to the aloe plant have been associated with the acetylated mannose-rich polysaccharide, also known as acemannan. However, the composition and structural features of these polysaccharides, as well as the beneficial properties associated with them, may be altered by different factors, such as the climate, soil, postharvest treatments, and processing. Further, different analytical methods have been used not only to identify but also to characterize the main polysaccharides found in parenchyma of A. vera leaf. Within this context, the main aim of this review is to summarize the most relevant information about the structural and compositional features of the main polysaccharides found in the A. vera gel as well as the most relevant analytical techniques used for their identification and their influence on the technological, functional, and beneficial properties related to the A. vera plant.