Elucidating the callus-to-shoot-forming mechanism in Capsicum annuum 'Dempsey' through comparative transcriptome analyses.

BACKGROUND: The formation of shoots plays a pivotal role in plant organogenesis and productivity. Despite its significance, the underlying molecular mechanism of de novo regeneration has not been extensively elucidated in Capsicum annuum 'Dempsey', a bell pepper cultivar. To address this, we performed a comparative transcriptome analysis focusing on the differential expression in C. annuum 'Dempsey' shoot, callus, and leaf tissue. We further investigated phytohormone-related biological processes and their interacting genes in the C. annuum 'Dempsey' transcriptome based on comparative transcriptomic analysis across five species. RESULTS: We provided a comprehensive view of the gene networks regulating shoot formation on the callus, revealing a strong involvement of hypoxia responses and oxidative stress. Our comparative transcriptome analysis revealed a significant conservation in the increase of gene expression patterns related to auxin and defense mechanisms in both callus and shoot tissues. Consequently, hypoxia response and defense mechanism emerged as critical regulators in callus and shoot formation in C. annuum 'Dempsey'. Current transcriptome data also indicated a substantial decline in gene expression linked to photosynthesis within regenerative tissues, implying a deactivation of the regulatory system governing photosynthesis in C. annuum 'Dempsey'. CONCLUSION: Coupled with defense mechanisms, we thus considered spatial redistribution of auxin to play a critical role in the shoot morphogenesis via primordia outgrowth. Our findings shed light on shoot formation mechanisms in C. annuum 'Dempsey' explants, important information for regeneration programs, and have broader implications for precise molecular breeding in recalcitrant crops.

Liquid crystal between two distributed Bragg reflectors enables multispectral small-pitch spatial light modulator.

The ability of controlling the phase of light at the subwavelength scale can be a game-changer due to its extraordinally wide angle-range in the wavefront shaping. By combining two conventional material and configuration, liquid crystal and distributed Bragg reflectors, we are getting close to this ultimate goal.

Optimization of Optical Phase Profile in Beam Deflector with Advanced Simulation Method for High Diffraction Efficiency.

Controlling the phase of light with a high efficiency and precision is essential for applications in imaging, tunable devices, and optical systems. Spatial light modulators (SLMs) based on liquid crystals (LCs) have been regarded as one of the best choices for the generation of phase profiles for the steering of light. The upper glass substrate has an unpatterned electrode for a common electrode, while the lower glass substrate has one-dimensional micro-patterned electrodes for controlling the single pixel level by the applied voltages. By applying different voltages to each electrode to create a sawtooth-shaped phase profile, the collimated input beam is deflected to the desired angle. To maximize the diffraction efficiency (DE) values, an advanced simulation method has been developed to find the optimized phase profile through the analysis of LC director distributions. The resulting diffraction patterns are investigated both computationally and experimentally, with a good agreement between the results obtained. Finally, the beam deflector (BD) system with an advanced driving algorithm has a high 1st order DE, about 60%, 37%, and 7.5% at 1°, 2.5°, and a maximum steering angle of 7.5°, respectively. The LC director distributions in relation to various diffraction angles are simulated and an experimental success in realizing enhanced DE for the beam steering device is presented.

Past, current, and future of holographic video display [Invited].

Holography has been considered as the ultimate technology for three-dimensional visual experience. Compared to the well-established static holographic technology, holographic video display is still in the research and development stage, before commercial products. This paper reviews various kinds of researches and related systems from the beginning of holographic video display to recent improvements, compares each specification, and describes their features. We discuss the key requirements for holographic display to be commercialized and widely used in everyday life.

Prediction of Life-Threatening Intracranial Hypertension During the Acute Phase of Traumatic Brain Injury Using Machine Learning.

Intracranial hypertension (IH) following acute phase traumatic brain injury (TBI) is associated with high mortality. Objective: This study proposes a novel parameter that may identify a potentially life-threatening IH (LTH) event and designs a machine learning model to predict LTH. Continuous recordings of intracranial pressure (ICP) and arterial blood pressure (ABP) from 273 TBI patients were used as the development dataset. The pressure-time dose (PTD) and pressure reactivity index (PRx) were calculated for each IH event, and an IH event with PRx > 0 and PTD > 5 was considered an LTH event. The association between the LTH parameters accumulated over five days and mortality was analyzed. A categorical boosting (CatBoost) model was employed to predict the occurrence of a future LTH event from the onset of IH using the ABP- and ICP-related parameters. Training and validation were performed on a total of 5,938 IH events. External performance evaluation was performed in 307 IH events included in the Cerebral Haemodynamic Autoregulatory Information System (CHARIS) database. The performance of the proposed model was evaluated through the area under the receiver operating characteristic curve (AUROC). The LTH parameters were able to distinguish between the deceased and surviving patients (AUROC > 0.7, p < 0.001). The CatBoost model predicted LTH with an AUROC = 0.7 on the external test dataset. This study demonstrated that the proposed LTH prediction model has a reasonable predictive capacity for mortality. The CatBoost model anticipates whether an IH event will develop into an LTH event. The findings of this study support the usefulness of ICP monitoring.

Electrically Actuated Varifocal Lens Based on Liquid-Crystal-Embedded Dielectric Metasurfaces.

Compact varifocal lenses are essential to various imaging and vision technologies. However, existing varifocal elements typically rely on mechanically actuated systems with limited tuning speeds and scalability. Here, an ultrathin electrically controlled varifocal lens based on a liquid crystal (LC) encapsulated dielectric metasurface is demonstrated. Enabled by the field-dependent LC anisotropy, applying a voltage bias across the LC cell modifies the local phase response of the silicon meta-atoms, in turn modifying the metalens focal length. In a numerical implementation, a voltage-actuated metalens with continuous zoom and up to 20% total focal shift is demonstrated. The LC-based metalens concept is experimentally verified through the design and fabrication of a bifocal metalens that facilitates high-contrast switching between two discrete focal lengths upon application of a 9.8 Vpp voltage bias. Owing to their ultrathin thickness and adaptable design, LC-driven dielectric metasurfaces open new opportunities for compact varifocal lensing in a diversity of modern imaging applications.

Slim-panel holographic video display.

Since its discovery almost 70 years ago, the hologram has been considered to reproduce the most realistic three dimensional images without visual side effects. Holographic video has been extensively researched for commercialization, since Benton et al. at MIT Media Lab developed the first holographic video systems in 1990. However, commercially available holographic video displays have not been introduced yet for several reasons: narrow viewing angle, bulky optics and heavy computing power. Here we present an interactive slim-panel holographic video display using a steering-backlight unit and a holographic video processor to solve the above issues. The steering-backlight unit enables to expand the viewing angle by 30 times and its diffractive waveguide architecture makes a slim display form-factor. The holographic video processor computes high quality holograms in real-time on a single-chip. We suggest that the slim-panel holographic display can provide realistic three-dimensional video in office and household environments.

A stable DNA-free screening system for CRISPR/RNPs-mediated gene editing in hot and sweet cultivars of Capsicum annuum.

BACKGROUND: DNA-free, clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein (Cas) ribonucleoprotein (RNP)-based genome editing is a simple, convincing, and promising tool for precision crop breeding. The efficacy of designed CRISPR-based genome editing tools is a critical prerequisite for successful precision gene editing in crops. RESULTS: This study demonstrates that soil-grown leaf- or callus-derived pepper protoplasts are a useful system for screening of efficient guide RNAs for CRISPR/Cas9 or CRISPR/Cas12a (Cpf1). CRISPR/Cas9 or Cpf1 were delivered as CRISPR/RNP complexes of purified endonucleases mixed with the designed single guide RNA, which can edit the target gene, CaMLO2 in two pepper cultivars with whole genome sequenced, Capsicum annuum 'CM334' and C. annuum 'Dempsey'. The designed guide RNAs (sgRNAs for Cas9 or crRNAs for Cpf1) are conserved for CaMLO2 in both CM334 and Dempsey and cleave CaMLO2 in vitro. CRISPR/Cas9- or /Cpf1-RNP complexes were transfected into purely isolated protoplasts of the hot pepper CM334 and sweet pepper Dempsey by PEG-mediated delivery. Targeted deep sequencing analysis indicated that the targeted CaMLO2 gene was differentially edited in both cultivars, depending on the applied CRISPR/RNPs. CONCLUSIONS: Pepper protoplast-based CRISPR guide-RNA selection is a robust method to check the efficacy of designed CRISPR tools and is a prerequisite for regenerating edited plants, which is a critical time-limiting procedure. The rapid and convincing selection of guide RNA against a target genome reduces the laborious efforts for tissue culture and facilitates effective gene editing for pepper improvement.

Large-area liquid crystal beam deflector with wide steering angle.

A slim beam deflector that satisfies both a large steering angle and a large area can be very useful in various applications. However, a smaller electrode pitch for a large steering angle and enlargement of its area are trade-off relations due to the limited number of control channels in an electrically tunable beam deflector system. For a large steering angle in the active area where actual diffraction occurs, an indium tin oxide electrode of 2 µm pitch was implemented through a stepper lithography. The via-hole process was developed to expand the reduced active area due to the small electrode pitch. We developed a beam deflector with 7200 controllable channels in an active area of 14.4mm×14.4mm. The maximum steering angle is 7.643° at a wavelength of 532 nm.

Functions of the Plant Qbc SNARE SNAP25 in Cytokinesis and Biotic and Abiotic Stress Responses.

Eukaryotes transport biomolecules between intracellular organelles and between cells and the environment via vesicle trafficking. Soluble N -ethylmaleimide-sensitive factor attachment protein receptors (SNARE proteins) play pivotal roles in vesicle and membrane trafficking. These proteins are categorized as Qa, Qb, Qc, and R SNAREs and form a complex that induces vesicle fusion for targeting of vesicle cargos. As the core components of the SNARE complex, the SNAP25 Qbc SNAREs perform various functions related to cellular homeostasis. The Arabidopsis thaliana SNAP25 homolog AtSNAP33 interacts with Qa and R SNAREs and plays a key role in cytokinesis and in triggering innate immune responses. However, other Arabidopsis SNAP25 homologs, such as AtSNAP29 and AtSNAP30, are not well studied; this includes their localization, interactions, structures, and functions. Here, we discuss three biological functions of plant SNAP25 orthologs in the context of AtSNAP33 and highlight recent findings on SNAP25 orthologs in various plants. We propose future directions for determining the roles of the less well-characterized AtSNAP29 and AtSNAP30 proteins.

Electrically tunable transmission-type beam deflector using liquid crystal with high angular resolution.

Highly efficient transmission-type beam deflectors that have high angular resolution have been widely used for various applications. Continuously tunable beam deflectors have also been needed for many purposes. An indium-tin-oxide (ITO), widely used for transparent electrodes, was placed on the upper and lower glass substrate. The ITO layer on the lower substrate was patterned by the contact mask aligner for relatively wide input and output pad compared to main grating ITO patterns in the active area. These input and output pads on the lower substrate are connected to each driving integrated circuit (IC), which has 360 channels for continuous control. A small pixel pitch of grating patterns of 6 µm (the electrode width is 3 µm with a 3 µm spacing) was developed, and the maximum diffraction angle is calculated and measured at 2.541° with a wavelength of 532 nm. A minimal cell gap of 2.5 µm was applied for the full 2π phase modulation by using a high-birefringence liquid crystal. A driving module for continuous beam steering is also developed and applied to the beam deflector system. A diffraction efficiency of about 50.9% is observed at an angle of diffraction about 2.541°.

Slim coherent backlight unit for holographic display using full color holographic optical elements.

The coherent backlight unit (BLU) using a holographic optical element (HOE) for full-color flat-panel holographic display is proposed. The HOE BLU consists of two reflection type HOEs that change the optical beam path and shape by diffraction. The illumination area of backlight is 150 mm x 90 mm and the thickness is 10 mm, which is slim compared to other conventional coherent backlight units for holographic display systems. This backlight unit exhibits a total efficiency of 8.0% at red (660 nm), 7.7% at green (532 nm), and 3.2% at blue (460 nm) using optimized recording conditions for each wavelength. As a result, we could get a bright full color hologram image.

Modulation efficiency of double-phase hologram complex light modulation macro-pixels.

The modulation efficiency of the double-phase hologram macro-pixel that is designed for complex modulation of light waves is defined and analyzed. The scale-down of the double-phase hologram macro-pixel associated with the construction of complex spatial light modulators is discussed.

Optimization of nanotube electrode geometry in a liquid crystal media from wavefront aberrations.

This paper presents experimental optimization of number and geometry of nanotube electrodes in a liquid crystal media from wavefront aberrations for realizing nanophotonic devices. The refractive-index gradient profiles from different nanotube geometries--arrays of one, three, four, and five--were studied along with wavefront aberrations using Zernike polynomials. The optimizations help the device to make application in the areas of voltage reconfigurable microlens arrays, high-resolution displays, wavefront sensors, holograms, and phase modulators.

Optimal synthesis of double-phase computer generated holograms using a phase-only spatial light modulator with grating filter.

We propose an optical system for synthesizing double-phase complex computer-generated holograms using a phase-only spatial light modulator and a phase grating filter. Two separated areas of the phase-only spatial light modulator are optically superposed by 4-f configuration with an optimally designed grating filter to synthesize arbitrary complex optical field distributions. The tolerances related to misalignment factors are analyzed, and the optimal synthesis method of double-phase computer-generated holograms is described.

Transparent liquid-crystal-based microlens array using vertically aligned carbon nanofiber electrodes on quartz substrates.

A novel transparent liquid-crystal-based microlens array has been fabricated using an array of vertically aligned multi-wall carbon nanofibers (MWCNFs) on a quartz substrate and its optical characteristics investigated. Electron beam lithography was used for the catalyst patterning on a quartz substrate to grow the MWCNF array of electrodes. The structure of the electrode array was determined through simulation to achieve the best optical performance. Both the patterned catalyst and growth parameters were optimized for optimal MWCNF properties. We report an in-depth optical characterization of these reconfigurable hybrid liquid crystal and nanofiber microlens arrays.