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Scientific Reports May 2021It is already known that there are many factors responsible for the successful formation of a graft union. However, the role of light has been little studied. In an...
It is already known that there are many factors responsible for the successful formation of a graft union. However, the role of light has been little studied. In an anatomical study, Scanning Electronic Microscope (SEM) was used to explore the effects of different light-emitting diodes (LEDs) on graft union formation in grafted tomato. In addition, the expression genes related to Auxin hormone signaling pathway (SAUR67, AUX1, ARF30, and LAX3) was investigated. The obtained results showed that the concrescence process occurred faster under R7:B3 light conditions, as compared to blue (B) and white fluorescent (WFL) lights. Red light application caused a delay in the vascular tissue differentiation, which may lead to callus development on both sides, causing junctional failure and resulting in ineffective graft junctional arrangement. The expression of genes related to Auxin hormone significantly increased by R7:B3 application. We suggest that LED spectra affects the graft development of tomato plants and can improve the performance of grafted tomato seedlings.
Topics: Color; Crop Production; Gene Expression Regulation, Plant; Indoleacetic Acids; Light; Solanum lycopersicum; Plant Proteins; Seedlings; Semiconductors; Signal Transduction
PubMed: 33972562
DOI: 10.1038/s41598-021-88971-5 -
Science (New York, N.Y.) Jan 2002The pack ice of Earth's polar oceans appears to be frozen white desert, devoid of life. However, beneath the snow lies a unique habitat for a group of bacteria and... (Review)
Review
The pack ice of Earth's polar oceans appears to be frozen white desert, devoid of life. However, beneath the snow lies a unique habitat for a group of bacteria and microscopic plants and animals that are encased in an ice matrix at low temperatures and light levels, with the only liquid being pockets of concentrated brines. Survival in these conditions requires a complex suite of physiological and metabolic adaptations, but sea-ice organisms thrive in the ice, and their prolific growth ensures they play a fundamental role in polar ecosystems. Apart from their ecological importance, the bacterial and algae species found in sea ice have become the focus for novel biotechnology, as well as being considered proxies for possible life forms on ice-covered extraterrestrial bodies.
Topics: Animals; Antarctic Regions; Bacterial Physiological Phenomena; Biotechnology; Ecosystem; Environment; Eukaryota; Exobiology; Freezing; Ice; Light; Seawater; Sodium Chloride; Temperature; Ultraviolet Rays
PubMed: 11809961
DOI: 10.1126/science.1063391 -
Sensors (Basel, Switzerland) Jan 2023Lensless holographic microscopy (LHM) comes out as a promising label-free technique since it supplies high-quality imaging and adaptive magnification in a lens-free,... (Review)
Review
Lensless holographic microscopy (LHM) comes out as a promising label-free technique since it supplies high-quality imaging and adaptive magnification in a lens-free, compact and cost-effective way. Compact sizes and reduced prices of LHMs make them a perfect instrument for point-of-care diagnosis and increase their usability in limited-resource laboratories, remote areas, and poor countries. LHM can provide excellent intensity and phase imaging when the twin image is removed. In that sense, multi-illumination single-holographic-exposure lensless Fresnel (MISHELF) microscopy appears as a single-shot and phase-retrieved imaging technique employing multiple illumination/detection channels and a fast-iterative phase-retrieval algorithm. In this contribution, we review MISHELF microscopy through the description of the principles, the analysis of the performance, the presentation of the microscope prototypes and the inclusion of the main biomedical applications reported so far.
Topics: Microscopy; Lighting; Holography; Lenses; Algorithms
PubMed: 36772511
DOI: 10.3390/s23031472 -
Advances in Cancer Research 2014Medical imaging plays a critical role in cancer diagnosis and planning. Many of these patients rely on surgical intervention for curative outcomes. This requires a... (Review)
Review
Medical imaging plays a critical role in cancer diagnosis and planning. Many of these patients rely on surgical intervention for curative outcomes. This requires a careful identification of the primary and microscopic tumors, and the complete removal of cancer. Although there have been efforts to adapt traditional-imaging modalities for intraoperative image guidance, they suffer from several constraints such as large hardware footprint, high-operation cost, and disruption of the surgical workflow. Because of the ease of image acquisition, relatively low-cost devices and intuitive operation, optical imaging methods have received tremendous interests for use in real-time image-guided surgery. To improve imaging depth under low interference by tissue autofluorescence, many of these applications utilize light in the near-infrared (NIR) wavelengths, which is invisible to human eyes. With the availability of a wide selection of tumor-avid contrast agents, advancements in imaging sensors, electronic and optical designs, surgeons are able to combine different attributes of NIR optical imaging techniques to improve treatment outcomes. The emergence of diverse commercial and experimental image guidance systems, which are in various stages of clinical translation, attests to the potential high impact of intraoperative optical imaging methods to improve speed of oncologic surgery with high accuracy and minimal margin positivity.
Topics: Animals; Fluorescence; Humans; Neoplasms; Surgery, Computer-Assisted
PubMed: 25287689
DOI: 10.1016/B978-0-12-411638-2.00005-7 -
Yakugaku Zasshi : Journal of the... 2022Technologies for the optical control of biomolecular functions have recently attracted considerable attention because they can be combined with advanced laser and... (Review)
Review
Technologies for the optical control of biomolecular functions have recently attracted considerable attention because they can be combined with advanced laser and microscopic techniques for diverse applications at the cellular and intravital levels. In this account, I review the summary of optical control technologies for biomolecular functions based on organic chemistry or protein science, and then introduce our recent studies on the development of small molecule-based photoregulation techniques. The first is the development of a photoactivatable protein labeling method based on a caged ligand. This method was applied to the photocontrol of intracellular protein dimerization and localization. The second is the development of a reversibly photoswitchable enzyme inhibitor, which was designed from the conformation of the inhibitor in the crystal structure of the enzyme-inhibitor complex. Based on our research strategies and results, I have also outlined the respective advantages and disadvantages of these two technologies: caged compounds and photoswitchable compounds.
Topics: Cell Physiological Phenomena; Ligands; Light; Proteins
PubMed: 35491156
DOI: 10.1248/yakushi.21-00203-4 -
International Journal of Environmental... Aug 2022We investigated ocular accommodative responses and pupil diameters under different light intensities in order to explore whether changes in light intensity aid effective...
PURPOSE
We investigated ocular accommodative responses and pupil diameters under different light intensities in order to explore whether changes in light intensity aid effective accommodation function training.
METHODS
A total of 29 emmetropic and myopic subjects (age range: 12-18 years) viewed a target in dynamic ambient light (luminance: 5, 100, 200, 500, 1000, 2000 and 3000 lux) and static ambient light (luminance: 1000 lux) at a 40 cm distance with refractive correction. Accommodation and pupil diameter were recorded using an open-field infrared autorefractor and an ultrasound biological microscope, respectively.
RESULTS
The changes in the amplitude of accommodative response and pupil diameter under dynamic lighting were 1.01 ± 0.53 D and 2.80 ± 0.75 mm, respectively, whereas in static lighting, those values were 0.43 ± 0.24 D and 0.77 ± 0.27 mm, respectively. The amplitude of accommodation and pupil diameter change in dynamic lighting (t = 6.097, < 0.001) was significantly larger than that under static lighting (t = 16.115, < 0.001).The effects of light level on both accommodation and pupil diameter were significant ( < 0.001).
CONCLUSION
Accommodation was positively correlated with light intensity. The difference was about 1.0 D in the range of 0-3000 lux, which may lay the foundation for accommodative training through light intervention.
Topics: Accommodation, Ocular; Adolescent; Child; Humans; Lighting; Pupil; Refraction, Ocular; Vision Tests
PubMed: 36078207
DOI: 10.3390/ijerph191710490 -
Optics Express Nov 2023Two decades after its introduction, optogenetics - a biological technique to control the activity of neurons or other cell types with light - remains a cutting edge and...
Two decades after its introduction, optogenetics - a biological technique to control the activity of neurons or other cell types with light - remains a cutting edge and promising tool to study biological processes. Its increasing usage in research varies widely from causally exploring biological mechanisms and neural computations, to neurostimulation and sensory restauration. To stimulate neurons in the brain, a variety of approaches have been developed to generate precise spatiotemporal light patterns. Yet certain constrains still exists in the current optical techniques to activate a neuronal population with both cellular resolution and millisecond precision. Here, we describe an experimental setup allowing to stimulate a few tens of neurons in a plane at sub-millisecond rates using 2-photon activation. A liquid crystal on silicon spatial light modulator (LCoS-SLM) was used to generate spatial patterns in 2 dimensions. The image of the patterns was formed on the plane of a digital micromirror device (DMD) that was used as a fast temporal modulator of each region of interest. Using fluorescent microscopy and patch-clamp recording of neurons in culture expressing the light-gated ion channels, we characterized the temporal and spatial resolution of the microscope. We described the advantages of combining the LCoS-SLM with the DMD to maximize the temporal precision, modulate the illumination amplitude, and reduce background activation. Finally, we showed that this approach can be extended to patterns in 3 dimensions. We concluded that the methodology is well suited to address important questions about the role of temporal information in neuronal coding.
Topics: Photons; Photic Stimulation; Holography; Neurons; Brain
PubMed: 38018006
DOI: 10.1364/OE.498644 -
Optics Express Aug 2022Structured Illumination Microscopy (SIM) is a key technology for high resolution and super-resolution imaging of biological cells and molecules. The spread of portable...
Structured Illumination Microscopy (SIM) is a key technology for high resolution and super-resolution imaging of biological cells and molecules. The spread of portable and easy-to-align SIM systems requires the development of novel methods to generate a light pattern and to shift it across the field of view of the microscope. Here we show a miniaturized chip that incorporates optical waveguides, splitters, and phase shifters, to generate a 2D structured illumination pattern suitable for SIM microscopy. The chip creates three point-sources, coherent and controlled in phase, without the need for further alignment. Placed in the pupil of a microscope's objective, the three sources generate a hexagonal illumination pattern on the sample, which is spatially translated thanks to thermal phase shifters. We validate and use the chip, upgrading a commercial inverted fluorescence microscope to a SIM setup and we image biological sample slides, extending the resolution of the microscope.
Topics: Lighting; Microscopy, Fluorescence; Optical Devices
PubMed: 36242132
DOI: 10.1364/OE.466225 -
Optics Express Sep 2022Graded index (GRIN) lens endoscopy has broadly benefited biomedical microscopic imaging by enabling accessibility to sites not reachable by traditional benchtop...
Graded index (GRIN) lens endoscopy has broadly benefited biomedical microscopic imaging by enabling accessibility to sites not reachable by traditional benchtop microscopes. It is a long-held notion that GRIN lenses can only be used as rigid probes, which may limit their potential for certain applications. Here, we describe bendable and long-range GRIN microimaging probes for a variety of potential micro-endoscopic biomedical applications. Using a two-photon fluorescence imaging system, we have experimentally demonstrated the feasibility of three-dimensional imaging through a 500-µm-diameter and ∼11 cm long GRIN lens subject to a cantilever beam-like deflection with a minimum bend radius of ∼25 cm. Bend-induced perturbation to the field of view and resolution has also been investigated quantitatively. Our development alters the conventional notion of GRIN lenses and enables a range of innovative applications. For example, the demonstrated flexibility is highly desirable for implementation into current and emerging minimally invasive clinical procedures, including a pioneering microdevice for high-throughput cancer drug selection.
Topics: Lenses; Lens, Crystalline; Photons; Endoscopy; Imaging, Three-Dimensional
PubMed: 36258589
DOI: 10.1364/OE.468827 -
Journal of Biomedical Optics May 2020The onset of several diseases is frequently marked with anomalous mechanical alteration of the affected tissue at the intersection of cells and their microenvironment.... (Review)
Review
SIGNIFICANCE
The onset of several diseases is frequently marked with anomalous mechanical alteration of the affected tissue at the intersection of cells and their microenvironment. Therefore, mapping the micromechanical attributes of the tissues could enhance our understanding of the etiology of human disease, improve the diagnosis, and help stratify therapies that target these mechanical aberrations.
AIM
We review the tremendous opportunities offered through using optics for imaging the micromechanical properties, at length scales inaccessible to other modalities, in both basic research and clinical medicine. We specifically focus on laser speckle rheology (LSR), a technology that quantifies the mechanical properties of tissues in a rapid, noncontact manner.
APPROACH
In LSR, the shear viscoelastic modulus is measured from the time-variant speckle intensity fluctuations reflected off the tissue. The LSR technology is engineered and configured into several embodiments, including bench-top optical systems, endoscopes for minimally invasive procedures, portable point-of-care devices, and microscopes.
RESULTS
These technological nuances have primed the LSR for widespread applications in diagnosis and therapeutic monitoring, as demonstrated here, in cardiovascular disease, coagulation disorders, and tumor malignancies.
CONCLUSION
The fast-paced technological advancements, elaborated here, position the LSR as a competent candidate for many more exciting opportunities in basic research and medicine.
Topics: Humans; Lasers; Light; Optical Devices; Rheology; Technology
PubMed: 32358928
DOI: 10.1117/1.JBO.25.5.050801