Publications by authors named "Bahk S"

Heat stress is a substantial and imminent threat to plant growth and development. Understanding its adverse effects on plant development at the molecular level is crucial for sustainable agriculture. However, the molecular mechanism underlying how heat stress causes developmental defects in flowers remains poorly understood.

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Mitogen-activated protein kinase (MPK) cascades are essential signal transduction components that control a variety of cellular responses in all eukaryotes. MPKs convert extracellular stimuli into cellular responses by the phosphorylation of downstream substrates. Although MPK cascades are predicted to be very complex, only limited numbers of MPK substrates have been identified in plants.

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Quercetin is a flavonol belonging to the flavonoid group of polyphenols. Quercetin is reported to have a variety of biological functions, including antioxidant, pigment, auxin transport inhibitor and root nodulation factor. Additionally, quercetin is known to be involved in bacterial pathogen resistance in through the transcriptional increase of () genes.

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Optical parametric chirped-pulse amplification (OPCPA) using high-energy Nd:glass lasers has the potential to produce ultra-intense pulses (>10 W/cm). We report on the performance of the final high-efficiency amplifier in an OPCPA system based on large-aperture (63 × 63-mm) partially deuterated potassium dihydrogen phosphate (DKDP) crystals. The seed beam (180-nm bandwidth, 110 mJ) was provided by the preceding OPCPA stages.

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Plasmodesmata (PD) play a critical role in symplasmic communication, coordinating plant activities related to growth & development, and environmental stress responses. Most developmental and environmental stress signals induce reactive oxygen species (ROS)-mediated signaling in the apoplast that causes PD closure by callose deposition. Although the apoplastic ROS signals are primarily perceived at the plasma membrane (PM) by receptor-like kinases (RLKs), such components involved in PD regulation are not yet known.

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Since plants are sessile organisms, developmental plasticity in response to environmental stresses is essential for their survival. Upon exposure to drought, lateral root development is suppressed to induce drought tolerance. However, the molecular mechanism by which the development of lateral roots is inhibited by drought is largely unknown.

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We present a theoretical and experimental analysis of the signal phase introduced by the pump-beam wavefront and spatial profile during optical parametric amplification (OPA) process. The theory predicts the appearance of an additional wavefront in the amplified signal beam that is proportional to the spatial derivative of the pump-beam wavefront. The effect of the pump-beam profile on the signal-beam wavefront is also investigated.

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The multiterawatt (MTW) laser, built initially as the prototype front end for a petawatt laser system, is a 1053 nm hybrid system with gain from optical parametric chirped-pulse amplification (OPCPA) and Nd:glass. Compressors and target chambers were added, making MTW a complete laser facility (output energy up to 120 J, pulse duration from 20 fs to 2.8 ns) for studying high-energy-density physics and developing short-pulse laser technologies and target diagnostics.

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Closed-form analytic phase solutions of three-wave interactions are presented for the first time, to the best of my knowledge. Cases from simple second-harmonic generation to the most general three-wave interactions without any constraints are considered. The phase amplification or deamplification behavior in the phase-sensitive parametric process is illustrated using the results obtained here.

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Flavonoids are well known for the coloration of plant organs to protect UV and ROS and to attract pollinators as well. Flavonoids also play roles in many aspects of physiological processes including pathogen resistance. However, the molecular mechanism to explain how flavonoids play roles in pathogen resistance was not extensively studied.

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Lateral root development is known to be regulated by Aux/IAA-ARF modules in . As components, several Aux/IAAs have participated in these Aux/IAA-ARF modules. In this study, to identify the biological function of IAA15 in plant developments, transgenic plant overexpressing the gain-of-function mutant of IAA15 (IAA15 OX) under the control of dexamethasone (DEX) inducible promoter, in which IAA15 protein was mutated by changing Pro-75 residue to Ser at the degron motif in conserved domain II, was constructed.

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Seed germination is a complex biological process controlled by various regulators, including phytohormones. Among these, abscisic acid and gibberellic acid inhibit and promote seed germination, respectively. Many studies have addressed the biological roles of auxin in plant growth and development, but very few have considered its role in seed germination.

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We describe the design and alignment of an unobscured reflective image relay for use in an ultra-broadband half-petawatt laser system in development at the University of Rochester's Laboratory for Laser Energetics. The design consists of four spherical mirrors in an unobscured configuration. We show the theoretical basis for such a four-mirror design using first-order optical matrix methods and nodal aberration theory.

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Background Context: Lumbosacral disc herniation (LDH) is one of the most frequent musculoskeletal diseases causative of sick leave in the workplace and morbidity in daily activities. Nonsurgical managements are considered as first line treatment before surgical treatment.

Purpose: This clinical practice guideline (CPG) is intended to provide physicians who treat patients diagnosed with LDH with a guideline supported by scientific evidence to assist in decision-making for appropriate and reasonable treatments.

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Spatio-temporal coupling in the field of ultrashort optical pulses is a technical enabler for applications but can result in detrimental effects such as increased on-target pulse duration and decreased intensity. Spectrally resolved spatial-phase measurements of a broadband field are demonstrated using a custom multispectral camera combined with two different wavefront sensors: a multilateral spatial shearing interferometer based on an amplitude checkerboard mask and an apodized imaged Hartmann sensor. The spatially and spectrally resolved phase is processed to quantify the commonly occurring pulse-front tilt and radial group delay, which are experimentally found to be in good agreement with models.

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We derive the relationship between Coddington's equations and the Gaussian curvature for a stigmatic reflective imaging system. This relationship allows parameterizing off-axis conic optical systems using traditional first-order optics by considering the effective curvature at the center of the off-axis sections. Specifically, we demonstrate parameterizing the system requirements of a 2× achromatic image relay for a terawatt laser system.

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Quantitative wavefront measurements are demonstrated using a Hartmann mask re-imaged onto a camera. The wavefront is reconstructed using standard algorithms applied to the difference of beamlet centroids determined from fluence distributions obtained for two different longitudinal locations of the mask. The wavefront of the optical wave in the object plane is measured independently of imaging-system collimation.

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Background Context: Epidural steroid injection has been used to treat back or radicular pain from lumbar and lumbosacral disc herniation (LDH). However, the superiority of transforaminal injection (TFESI) to caudal injection (CESI) remains controversial.

Purpose: This systematic review and meta-analysis aimed to investigate whether TFESI was more useful than CESI for achieving clinical outcomes in patients with LDH.

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We present a patient who showed a sterile abscess after facial bone fixation with bioabsorbable plates and screws. He had zygomaticomaxillary complex and periorbital fracture due to falling down. The displaced bones were treated by open reduction and internal fixation successfully using bioabsorbable plate system.

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Two-dimensional chromatic aberrations are characterized by a single-shot scheme based on a simultaneous measurement of chromatically diversified focal spots. The chromatic diversity is introduced by a 2-D grating with holographic defocus terms. The chromatic aberrations in the beam are either subtracted or added by the additional known chromatic aberrations in the grating, depending on the diffraction order.

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Reconstruction of soft tissue defects in the foot remains a challenge due to its specialized tissue for weightbearing and ambulation. Considering the principle of replacing "like with like," adjacent soft tissues would be a best option for a donor site. Although several kinds of reverse-flow island flaps for the lower leg have been well described, intrinsic foot reverse flow flaps have been rarely reported.

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The expression of CBF (C-repeat-binding factor) genes is required for freezing tolerance in Arabidopsis thaliana. CBFs are positively regulated by INDUCER OF CBF EXPRESSION1 (ICE1) and negatively regulated by MYB15. These transcription factors directly interact with specific elements in the CBF promoters.

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The infraorbital nerve (ION) can easily be damaged by orbital trauma and periorbital surgical manipulations, due to its abutment to the orbital floor. Anatomic variability of the ION and surrounding structures has infrequently been documented. The aim of this study is to give precise anatomical knowledge about the ION with surrounding structures, to avoid iatrogenic injury of the ION during periorbital procedures.

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Facial synkinesis is the simultaneous contraction of the certain facial musculature accompanying a motion of designated muscle in the face. With the exception of rare afflictions that are congenital in origin, most patients develop as a sequel to facial nerve paralysis due to trauma, tumor, and surgical injury. As an idiopathic congenital form, oculo-nasal synkinesis which reveals co-contraction of orbicularis oculi and the compressor narium minor muscles which are innervated by separate branches of the facial nerve have been already reported.

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Background: Like most animals, insects rely on their olfactory systems for finding food and mates and in avoiding noxious chemicals and predators. Most insect olfactory neurons express an odorant-specific odorant receptor (OR) along with Orco, the olfactory co-receptor. Orco binds ORs and permits their trafficking to the dendrites of antennal olfactory sensory neurons (OSNs), where together, they are suggested to form heteromeric ligand-gated non-selective cation channels.

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