Stepwise Modulation Research Articles

Modulating the Microenvironment of Coumarin Dyes within Multihierarchical Supraparticles: En Route toward Versatile Luminescent Dual‐Threshold Temperature Indicators with Ratiometric Readout

AbstractTemperature indicators trace (un)desired thermal impacts across their thermal history upon readout at every point of interest via defined irreversible signal changes. Ratiometric luminescent temperature indicators are attractive due to their fast, sensitive, contactless, spatially‐resolved, and self‐referenced readout. However, they have a limited working range as commonly only one specific temperature‐induced physicochemical effect is exploited. Herein, dual‐threshold temperature indicator supraparticles (SPs) are introduced that expand the working range of individual luminescent probes and enhance the extractable information on the thermal history. These SPs derive their functionality from the synergistic interplay of three spectrally distinguishable luminescent species assembled in one multihierarchical, micrometer‐sized particle of hybrid organic‐inorganic nature. This engineered nanostructure enables the stepwise modulation of the physicochemical microenvironment of two incorporated coumarin species at programmable threshold temperatures, resulting in distinct changes in their emission. As these changes are based on dye‐specific mechanisms that are induced in consecutive temperature regimes, the SPs achieve a scarcely reported broad working range (60–200 °C) with temperature‐dependent response times of minutes to seconds. From a broader perspective, the conceptualized SPs pioneer in how multiple individual luminescent probes with different excitation‐emission properties and indicator mechanisms are synergistically united in one advanced indicator system by precise material engineering.

Electronic state modulation of Ag30 nanoclusters within a ring-shaped polyoxometalate.

Atomically precise Ag nanoclusters display distinctive properties that are dictated by their structures and electronic states. However, manipulating the electronic states of Ag nanoclusters is challenging owing to their inherent instability and susceptibility to undesired structural changes, decomposition, and aggregation. Recently, we reported the synthesis of a body-centered cubic {Ag30}22+ nanocluster encapsulated within a ring-shaped polyoxometalate (POM) [P8W48O184]40- by reacting 16 Ag+-containing [P8W48O184]40- with Ag+ using N,N-dimethylformamide (DMF) as a mild reducing agent. This led to a redox-induced structural transformation into a face-centered cubic {Ag30}16+ nanocluster. In this study, we demonstrated the modulation of the electronic states of Ag30 nanoclusters within the ring-shaped POM through two different approaches. A face-centered cubic {Ag30}18+ nanocluster, featuring distinct oxidation states compared to previously reported {Ag30}22+ and {Ag30}16+ nanoclusters, was synthesized using tetra-n-butylammonium borohydride, a stronger reducing agent than DMF, in the reaction of 16 Ag+-containing [P8W48O184]40- and Ag+. Additionally, by leveraging the acid-base properties of POMs, we demonstrated the reversible, stepwise modulation of the charge distribution in the Ag30 nanocluster through controlling protonation states of the ring-shaped POM ligand. These results highlight the potential of engineering POM-stabilized Ag nanoclusters with diverse structures and electronic states, thereby facilitating the exploration of novel properties and applications utilizing the unique characteristics of the POM ligands.

Preparation of gradient refractive index films on glass surface and its anti-reflection properties

This study presents the creation of a gradient refractive index film on the surface of aluminosilicate glass using a two-step process involving chemical etching and subsequent multilayer sol-gel coating with hollow silica nanospheres. The primary objective was to achieve effective anti-reflection properties. Various analytical techniques such as FESEM, TEM, UV-Vis-NIR spectrophotometry, ellipsometer, and FT-IR spectrometry were employed to investigate the impact of glass surface morphology and refractive index on optical characteristics. The results revealed the successful formation of a porous structure on the glass surface through chemical etching. Subsequently, this porous structure was uniformly filled and layered with hollow silica spheres of different sizes, resulting in a stepwise gradient refractive index coating. Notably, the pore size of the hollow spherical silica colloidal particles progressively increased from 0 nm to 23 nm, corresponding to distinct film thicknesses and refractive indices. This stepwise modulation contributed to the establishment of a gradient refractive index within the coating. By transitioning the refractive index of the film layer from that of glass to air, the film acted as a matching layer, thereby achieving broadband anti-reflection. The efficiency of this anti-reflection was demonstrated by an increase in transmittance from an initial value of 91.8–95.32% following the two-step etching process. With the subsequent SiO2 coating, the transmittance continued to improve, ultimately reaching a high value of 97.47%. This improvement in transmittance was attributed to the gradual enhancement of the film layer.

Stepwise modulation of apical orientational cell adhesions for vertebrate neurulation.

Neurulation transforms the neuroectoderm into the neural tube. This transformation relies on reorganising the configurational relationships between the orientations of intrinsic polarities of neighbouring cells. These orientational intercellular relationships are established, maintained, and modulated by orientational cell adhesions (OCAs). Here, using zebrafish (Danio rerio) neurulation as a major model, we propose a new perspective on how OCAs contribute to the parallel, antiparallel, and opposing intercellular relationships that underlie the neural plate-keel-rod-tube transformation, a stepwise process of cell aggregation followed by cord hollowing. We also discuss how OCAs in neurulation may be regulated by various adhesion molecules, including cadherins, Eph/Ephrins, Claudins, Occludins, Crumbs, Na+ /K+ -ATPase, and integrins. By comparing neurulation among species, we reveal that antiparallel OCAs represent a conserved mechanism for the fusion of the neural tube. Throughout, we highlight some outstanding questions regarding OCAs in neurulation. Answers to these questions will help us understand better the mechanisms of tubulogenesis of many tissues.

Three-dimensional planning accuracy and follow-up of Le Fort I osteotomy in cleft lip/palate patients.

ObjectivesOur aim was to determine the accuracy of the three-dimensional (3D) virtual planning and stability of LeFort I osteotomy in cleft lip and/or palate patients (CLP) using a validated 3D method. Materials and methodsEight patients with a history of cleft lip/palate treated with LeFort I osteotomy for maxillary hypoplasia between January 2016 and April 2020 were included in this retrospective study. Three-dimensional virtual planning was performed using Proplan software then transferred to the operation theater via 3D printed occlusal wafers. The accuracy of the 3D planning and the 1-year stability of the maxilla were evaluated by means of a validated semiautomatic stepwise module in Amira software resulting into 3 linear measurements: anterior/posterior, medial/lateral, superior/inferior and 3 rotational measurements: pitch, roll, yaw. ResultsThe largest mean absolute difference (MAD) for accuracy assessment was found in the A/P direction (2.75mm±2.25 mm) and in pitch (3.23°±2.11°). For A/P translation, an error of >2 mm was observed in 5(62.5%), for S/I translation an error of >2 mm was observed in 4(50.0%) of the 8 patients, whereas for pitch 3 patients(37,5%) showed an error >4° At one year follow-up, the largest linear and rotational MAD was found in the A/P direction (1.20mm±0.92 mm) and in pitch (3.31°±2.31°). ConclusionsFindings of this study show that 3D virtual computer-assisted orthognathic surgery enables an accurate repositioning of the hypoplastic maxilla in CLP patients. However, A/P translations and pitch rotations remain challenging to achieve during surgery. These movements were also found to be least stable at one year follow-up.

The GLI code controls HNF1A levels during foregut differentiation.

Differentiation of human induced pluripotent stem cells towards pancreatic islet endocrine cells is a complex process, involving the stepwise modulation of key developmental pathways, such as the Hedgehog signaling inhibition during early differentiation stages. In tandem with this active inhibition, key transcription factors for the islet endocrine cell fate, such as HNF1A, show specific changes in their expression patterns. Here we designed a pilot study aimed at investigating the potential interconnection between HH-signaling inhibition and the increase in the HNF1A expression during early regeneration, by inducing changes in the GLI code. This unveiled a link between the two, where GLI3-R mediated Hedgehog target genes inhibition is apparently required for HNF1A efficient expression.

Optogenetic polymerization and assembly of electrically functional polymers for modulation of single-neuron excitability.

Ionic conductivity and membrane capacitance are two foundational parameters that govern neuron excitability. Conventional optogenetics has emerged as a powerful tool to temporarily manipulate membrane ionic conductivity in intact biological systems. However, no analogous method exists for precisely manipulating cell membrane capacitance to enable long-lasting modulation of neuronal excitability. Genetically targetable chemical assembly of conductive and insulating polymers can modulate cell membrane capacitance, but further development of this technique has been hindered by poor spatiotemporal control of the polymer deposition and cytotoxicity from the widely diffused peroxide. We address these issues by harnessing genetically targetable photosensitizer proteins to assemble electrically functional polymers in neurons with precise spatiotemporal control. Using whole-cell patch-clamp recordings, we demonstrate that this optogenetic polymerization can achieve stepwise modulation of both neuron membrane capacitance and intrinsic excitability. Furthermore, cytotoxicity can be limited by controlling light exposure, demonstrating a promising new method for precisely modulating cell excitability.

Hollywood Harmony: Musical Wonder and the Sound of Cinema

Hollywood Harmony: Musical Wonder and the Sound of Cinema

Interprofessional education on complex patients in nursing homes: a focus group study

BackgroundAn ageing population leads up to increasing multi-morbidity and polypharmacy. This demands a comprehensive and interprofessional approach in meeting patients’ complex needs. This study describes graduate students’ experiences of working practice based in interprofessional teams with complex patients’ care needs in nursing homes.MethodStudents from advanced geriatric nursing, clinical nutrition, dentistry, medicine and pharmacy at the University of Oslo in Norway were assigned to groups to examine and develop a care plan for a nursing home patient during a course. Focus groups were used, 21 graduate students participating in four groups. Data were collected during spring 2018, were inductively analysed according to a thematic analysis method (Systematic Text Condensation). An analytical framework of co-ordination practices was applied to get an in-depth understanding of the data.ResultsThree themes were identified: 1) Complex patients as learning opportunities- an eye-opener for future interprofessional collaboration 2) A cobweb of relations, and 3) Structural facilitators for new collective knowledge. Graduate university students experienced interprofessional education (IPE) on complex patients in nursing homes as a comprehensive learning arena. Overall, different co-ordination practices for work organization among the students were identified.ConclusionsIPE in nursing homes facilitated the students’ scope from a fragmented approach of the patients towards a relational and collaborative practice that can improve patient care and strengthen understanding of IPE. The study also demonstrated the need for preparatory teamwork training to gain maximum benefit from the experience. Something that can be organized by the education institutions in the form of a stepwise learning module and as an online pre-training course in interprofessional teamwork. Further, focusing on the need for well thought through processes of the activity by the institutions and the timing the practice component in students’ curricula. This could ensure that IPE is experienced more efficient by the students.

Colorimetric properties and structural evolution of cathodic electrochromic WO3 thin films

Cathodic amorphous tungsten trioxide (WO3) thin films have been deposited by reactive direct current magnetron sputtering and have been studied for their colorimetric and electrochromic properties. Those studies were carried out under two different potential cycling process: (i) switching mode (the response between coloration and bleaching in increasing potential steps) and (ii) modulation mode (the stepwise modulation to coloration with increasing potential and back to bleaching). Optical measurements, performed as a function of applied potential, showed excellent transmittance contrasts (∼80%) between colored and bleached states. The color stimuli and the changes that take place upon reversible switching or modulation were recorded based on the Commisson International de l’Éclairage (CIE) system. It was found that, under various potentials, significant changes occurred in the hue and saturation for WO3, as exhibited by the CIE 1931 xy chromaticity coordinates. As WO3 was reduced (W6+ + e– → W5+), a sharp decrease in luminance was observed. Excellent reversibility is demonstrated not only by colorimetric properties, but also by the corresponding intrinsic structures of the films, as investigated by µ-Raman spectroscopy. Furthermore, the WO3 films displayed a fast response time and good long-term cycling durability, which was attributed to their amorphous nature.

Influence of an External Signal with Harmonic or Stepwise-Modulated Parameters on the High-Power Gyrotron Operation

Nonlinear dynamics of a gyrotron with high-order operating mode, driven by an external signal with harmonic or stepwise modulation of its parameters or by two monochromatic signals, was studied theoretically. Conditions for locking and control of the radiation frequency were found. Exit from the locking regime is accompanied by the beats of the operating mode or excitation of spurious modes. Simulations were performed using a megawatt-power TE28.12 mode gyrotron as the example (Chirkov et al., Appl Phys Lett 106(26), 2015).

Hair-bearing human skin generated entirely from pluripotent stem cells.

The skin is a multi-layered organ equipped with appendages (i.e. follicles and glands) critical for regulating bodily fluid retention and temperature, guarding against external stresses, and mediating touch and pain sensation1,2. Reconstruction of appendage-bearing skin in cultures and in bioengineered grafts remains an unmet biomedical challenge3–9. Here, we report an organoid culture system that generates complex skin from human pluripotent stem cells. We use step-wise modulation of the TGFβ and FGF signalling pathways to co-induce cranial epithelial cells and neural crest cells within a spherical cell aggregate. During 4–5 months incubation, we observe the emergence of a cyst-like skin organoid composed of stratified epidermis, fat-rich dermis, and pigmented hair follicles equipped with sebaceous glands. A network of sensory neurons and Schwann cells form nerve-like bundles that target Merkel cells in organoid hair follicles, mimicking human touch circuitry. Single-cell RNA-sequencing and direct comparison to foetal specimens suggest that skin organoids are equivalent to human facial skin in the second-trimester of development. Moreover, we show that skin organoids form planar hair-bearing skin when grafted on nude mice. Together, our results demonstrate that nearly complete skin can self-assemble in vitro and be used to reconstitute skin in vivo. We anticipate skin organoids will be foundational to future studies of human skin development, disease modelling, or reconstructive surgery.

Electrochromic and colorimetric properties of anodic NiO thin films: Uncovering electrochromic mechanism of NiO

In this work anodic NiO electrochromism is investigated under two potential cycling modes: i) the response between coloration and bleaching in increasing potential steps (switching); ii) the stepwise modulation to coloration with increasing potential and back to bleaching (modulation). The films’ response is investigated by optical spectroscopy, colorimetry studies, Raman spectroscopy, XRD, cyclic voltammetry and chronoamperometry. Using the CIE (Commisson International de l’Éclairage) system of colorimetry the color stimuli of the films and the changes that take place upon reversible switching/modulation are recorded under various potentials. As shown by the CIE 1931 xy chromaticity coordinates, when NiO film is oxidized, a sharp decrease in luminance is observed. Optical measurements, performed as a function of applied potential, show excellent contrast between colored and bleached states. Up to now, for NiO, the coloration mechanism was considered as a surface phenomenon. Here, for the first time we show that upon ion insertion/extraction the lattice constant of NiO changes, proving that the EC coloration mechanism involves the unit cells in the bulk material. Furthermore, the fraction ratio of Li to Ni atoms (LiNi) is proposed. Considering the actual film fabrication conditions, the x value in LixNiO is found to be equal to 0.0046.

Towards monitoring laser welding process via a coaxial pyrometer

Abstract The sensing and controlling of weld metrics, such as weld bead width, depth of penetration and defects, are important for adopting laser welding technology into the industry to meet the increasing demands on product quality. In this research, a weld monitoring system for laser welding is designed using a coaxial infrared pyrometer. Welds with different geometries are induced by stepwise modulation of laser power in bead-on-plate welds at three different beam diameters. The temperature signal calculated from coaxial infrared radiation are successfully correlated to weld width and penetration depth, measured by cross-sectional optical microscopy. Moreover, the temperature signal can be used as a direct indicator of welding transition mode between conduction and keyhole. The monitor is also capable of tracking geometric defects during laser welding. The use of coaxial infrared radiation can be a promising tool for the on-line detection and control of weld metrics, hence, to improve weld quality.

Rapid Differentiation of Asian and American Ginseng by Differential Ion Mobility Spectrometry-Tandem Mass Spectrometry Using Stepwise Modulation of Gas Modifier Concentration.

This study reports a rapid and robust method for the differentiation of Asian and American ginseng samples based on differential ion mobility spectrometry-tandem mass spectrometry (DMS-MS/MS). Groups of bioactive ginsenoside/pseudo-ginsenoside isomers, including Rf/Rg1/F11, Rb2/Rb3/Rc, and Rd/Re, in the ginseng extracts were sequentially separated using DMS with stepwise changes in the gas modifier concentration prior to MS analysis. The identities of the spatially separated ginsenoside/pseudo-ginsenoside isomers were confirmed by their characteristic compensation voltages at specific modifier loading and MS/MS product ions. As expected, Asian ginseng samples contained some Rf and an insignificant amount of F11, whereas American ginseng samples had a high level of F11 but no Rf. The origin of the whole and sliced ginseng could further be confirmed using the quantitative ratios of three sets of ginsenoside markers, namely, Rg1/Re, Rb1/Rg1, and Rb2/Rc. Based on our results, new benchmark ratios of Rg1/Re < 0.15, Rb1/Rg1 > 2.15, and Rb2/Rc < 0.26 were proposed for American ginseng (as opposed to Asian ginseng).

Mismatch Negativity on Presentation of Amplitude-Modulated Sound Signals

The studies reported here addressed analysis of the N1 and P2 components and mismatch negativity (MMN) on discrimination of signals with dynamic changes in intensity in different acoustic contexts. Changes in context in the conditions of the oddball paradigm were created on the basis that each stimulus operated both as a standard and as a deviant in different series, such that the physical differences between signals remained unaltered and their functional relationship flipped to the opposite. Three types of sound signal were used: stimuli with constant intensity and two amplitude-modulated stimuli (linear and stepwise, each with an increase or decrease in intensity). Increases and decreases in the intensity of deviant stimuli induced MMN in the late latency period (>250 msec) without overlap with the N1 component. The difference in signals with linear and stepwise amplitude modulation indexed by mismatch negativity was determined by the direction of deviation in the structure of the sound series. Increment MMN anticipated decrement MMN by 90–100 msec regardless of the type of modulation. Amplitude differences were seen in responses to deviants with stepwise modulation in the context of consistent standards: increment MMN was greater than decrement MMN. The acoustic context affected only increment MMN. These results are consistent with views of the asymmetry in the perception of increasing and decreasing sound intensity, associated with their different biological significance.

Three-dimensional planning accuracy and follow-up protocol in orthognathic surgery: a validation study

The purpose of the study was to propose and validate a three-dimensional (3D) tool for the assessment of orthognathic surgery planning accuracy and postoperative follow-up. A total of 15 patients (four male, 11 female; mean age 29.6 years) with skeletal class II and III, who underwent bimaxillary surgery were recruited for the study. All patients had preoperative computed tomography (CT), and cone-beam computerized tomography (CBCT) scans 1–6 weeks and 6 months postoperatively. The data was exported to a customized stepwise module developed in Amira software resulting in the accuracy being presented as translational and rotational differences between the planning and the actual outcome. To evaluate the reliability of the proposed method, intra-class correlation coefficient (ICC) was applied at a 95% confidence interval on the translational and rotational output of two observers. The inter- and intra-observer reliability were found to be high (ICC range: 0.94–0.98) with mean variability of less than 0.4mm and 0.7° for translational and rotational movements for both planning accuracy and follow-up protocols. The study provides a reliable, quantitative and time-efficient method for evaluating the accuracy of virtual surgical planning and postoperative follow-up.

Reversible CO2-Responsive and Photopolymerizable Prepolymers for Stepwise Regulation on Demand

CO2-responsive and photopolymerizable prepolymers are designed and synthesized. Their good photopolymerization kinetics and reversible CO2 and N2 responses to a bulk state and in a solution are reported. Stepwise modulation is verified in template imprinting. Results reveal that stable and high-resolution patterns can be produced by imprinting liquid prepolymers in CO2 atmosphere, erased by warm heating, or retained permanently by chemical cross-linking through photopolymerization with the aid of a photoinitiator. By contrast, only blurry patterns are obtained in air.

High-Resolution FluoRespirometry and OXPHOS Protocols for Human Cells, Permeabilized Fibers from Small Biopsies of Muscle, and Isolated Mitochondria.

Protocols for High-Resolution FluoRespirometry of intact cells, permeabilized cells, permeabilized muscle fibers, isolated mitochondria, and tissue homogenates offer sensitive diagnostic tests of integrated mitochondrial function using standard cell culture techniques, small needle biopsies of muscle, and mitochondrial preparation methods. Multiple substrate-uncoupler-inhibitor titration (SUIT) protocols for analysis of oxidative phosphorylation (OXPHOS) improve our understanding of mitochondrial respiratory control and the pathophysiology of mitochondrial diseases. Respiratory states are defined in functional terms to account for the network of metabolic interactions in complex SUIT protocols with stepwise modulation of coupling control and electron transfer pathway states. A regulated degree of intrinsic uncoupling is a hallmark of oxidative phosphorylation, whereas pathological and toxicological dyscoupling is evaluated as a mitochondrial defect. The noncoupled state of maximum respiration is experimentally induced by titration of established uncouplers (CCCP, FCCP, DNP) to collapse the protonmotive force across the mitochondrial inner membrane and measure the electron transfer (ET) capacity (open-circuit operation of respiration). Intrinsic uncoupling and dyscoupling are evaluated as the flux control ratio between non-phosphorylating LEAK respiration (electron flow coupled to proton pumping to compensate for proton leaks) and ET capacity. If OXPHOS capacity (maximally ADP-stimulated O2 flux) is less than ET capacity, the phosphorylation pathway contributes to flux control. Physiological substrate combinations supporting the NADH and succinate pathway are required to reconstitute tricarboxylic acid cycle function. This supports maximum ET and OXPHOS capacities, due to the additive effect of multiple electron supply pathways converging at the Q-junction. ET pathways with electron entry separately through NADH (pyruvate and malate or glutamate and malate) or succinate (succinate and rotenone) restrict ET capacity and artificially enhance flux control upstream of the Q-cycle, providing diagnostic information on specific ET-pathway branches. O2 concentration is maintained above air saturation in protocols with permeabilized muscle fibers to avoid experimental O2 limitation of respiration. Standardized two-point calibration of the polarographic oxygen sensor (static sensor calibration), calibration of the sensor response time (dynamic sensor calibration), and evaluation of instrumental background O2 flux (systemic flux compensation) provide the unique experimental basis for high accuracy of quantitative results and quality control in High-Resolution FluoRespirometry.

Teaching Spinal Cord Neuroanatomy through Drawing: An Interactive, Step-Wise Module.

This interactive, case-based module was created to provide medical students with self-guided practice to improve their confidence with, and understanding of, neuroanatomy. The module was created to supplement neuroanatomy instruction. It is based on the idea that pictures and drawings are effective tools for teaching clinical neuroanatomy, especially when paired with a step-wise approach to solving clinical cases. The learning module focuses on the basics of spinal cord anatomy and lesion localization, topics fundamental to neuroanatomy. Students who have had a basic introduction to these topics in their neuroanatomy course will find this module a useful educational supplement. A full version of the module, which includes a self-drawing component for additional reinforcement, can be completed in approximately an hour. A shorter version without the self-drawing component, can be completed in less time. The materials associated with the module include an answer packet to use as a guide through the module cases, and both pre- and postmodule practice questions for self-evaluation. Both modules were tested at our institution by separate groups of second-year medical students in the early portion of their neuroanatomy course. Both module versions showed significant improvement in confidence levels when describing spinal cord anatomy and lesion localization. Furthermore, students were highly satisfied with the material and reported they were likely to reuse it for additional studying. The use of this module by medical students during their neuroanatomy course provides a step-wise, case-based approach that simplifies the learning of learning neuroanatomy, and improves their confidence through pictures and drawings.