1
|
Roy S, Wang D, Rudzite AM, Perry B, Scalabrino ML, Thapa M, Gong Y, Sher A, Field GD. Large-scale interrogation of retinal cell functions by 1-photon light-sheet microscopy. CELL REPORTS METHODS 2023; 3:100453. [PMID: 37159670 PMCID: PMC10163030 DOI: 10.1016/j.crmeth.2023.100453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/05/2023] [Accepted: 03/24/2023] [Indexed: 05/11/2023]
Abstract
Visual processing in the retina depends on the collective activity of large ensembles of neurons organized in different layers. Current techniques for measuring activity of layer-specific neural ensembles rely on expensive pulsed infrared lasers to drive 2-photon activation of calcium-dependent fluorescent reporters. We present a 1-photon light-sheet imaging system that can measure the activity in hundreds of neurons in the ex vivo retina over a large field of view while presenting visual stimuli. This allows for a reliable functional classification of different retinal cell types. We also demonstrate that the system has sufficient resolution to image calcium entry at individual synaptic release sites across the axon terminals of dozens of simultaneously imaged bipolar cells. The simple design, large field of view, and fast image acquisition make this a powerful system for high-throughput and high-resolution measurements of retinal processing at a fraction of the cost of alternative approaches.
Collapse
Affiliation(s)
- Suva Roy
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Depeng Wang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Andra M. Rudzite
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Benjamin Perry
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Miranda L. Scalabrino
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
- Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles, Los Angeles, CA 90024, USA
| | - Mishek Thapa
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
- Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles, Los Angeles, CA 90024, USA
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Alexander Sher
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Greg D. Field
- Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA
- Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles, Los Angeles, CA 90024, USA
| |
Collapse
|
2
|
Tomanič T, Rogelj L, Milanič M. Robustness of diffuse reflectance spectra analysis by inverse adding doubling algorithm. BIOMEDICAL OPTICS EXPRESS 2022; 13:921-949. [PMID: 35284194 PMCID: PMC8884198 DOI: 10.1364/boe.443880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/12/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Analysing diffuse reflectance spectra to extract properties of biological tissue requires modelling of light transport within the tissue, considering its absorption, scattering, and geometrical properties. Due to the layered skin structure, skin tissue models are often divided into multiple layers with their associated optical properties. Typically, in the analysis, some model parameters defining these properties are fixed to values reported in the literature to speed up the fitting process and improve its performance. In the absence of consensus, various studies use different approaches in fixing the model parameters. This study aims to assess the effect of fixing various model parameters in the skin spectra fitting process on the accuracy and robustness of a GPU-accelerated two-layer inverse adding-doubling (IAD) algorithm. Specifically, the performance of the IAD method is determined for noiseless simulated skin spectra, simulated spectra with different levels of noise applied, and in-vivo measured reflectance spectra from hyperspectral images of human hands recorded before, during, and after the arterial occlusion. Our results suggest that fixing multiple parameters to a priori known values generally improves the robustness and accuracy of the IAD algorithm for simulated spectra. However, for in-vivo measured spectra, these values are unknown in advance and fixing optical parameters to incorrect values significantly deteriorates the overall performance. Therefore, we propose a method to improve the fitting performance by pre-estimating model parameters. Our findings could be considered in all future research involving the analysis of diffuse reflectance spectra to extract optical properties of skin tissue.
Collapse
Affiliation(s)
- Tadej Tomanič
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia
| | - Luka Rogelj
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia
| | - Matija Milanič
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia
- Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| |
Collapse
|
3
|
Garzón I, Chato-Astrain J, González-Gallardo C, Ionescu A, Cardona JDLC, Mateu M, Carda C, Pérez MDM, Martín-Piedra MÁ, Alaminos M. Long-Term in vivo Evaluation of Orthotypical and Heterotypical Bioengineered Human Corneas. Front Bioeng Biotechnol 2020; 8:681. [PMID: 32671048 PMCID: PMC7327129 DOI: 10.3389/fbioe.2020.00681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/02/2020] [Indexed: 12/03/2022] Open
Abstract
Purpose Human cornea substitutes generated by tissue engineering currently require limbal stem cells for the generation of orthotypical epithelial cell cultures. We recently reported that bioengineered corneas can be fabricated in vitro from a heterotypical source obtained from Wharton’s jelly in the human umbilical cord (HWJSC). Methods Here, we generated a partial thickness cornea model based on plastic compression nanostructured fibrin-agarose biomaterials with cornea epithelial cells on top, as an orthotypical model (HOC), or with HWJSC, as a heterotypical model (HHC), and determined their potential in vivo usefulness by implantation in an animal model. Results No major side effects were seen 3 and 12 months after implantation of either bioengineered partial cornea model in rabbit corneas. Clinical results determined by slit lamp and optical coherence tomography were positive after 12 months. Histological and immunohistochemical findings demonstrated that in vitro HOC and HHC had moderate levels of stromal and epithelial cell marker expression, whereas in vivo grafted corneas were more similar to control corneas. Conclusion These results suggest that both models are potentially useful to treat diseases requiring anterior cornea replacement, and that HHC may be an efficient alternative to the use of HOC which circumvents the need to generate cornea epithelial cell cultures.
Collapse
Affiliation(s)
- Ingrid Garzón
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - Jesus Chato-Astrain
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | | | - Ana Ionescu
- Biomaterials Optics Group, Department of Optics, University of Granada, Granada, Spain
| | | | - Miguel Mateu
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - Carmen Carda
- Department of Histology and Pathology, University of Valencia, Valencia, Spain
| | - María Del Mar Pérez
- Biomaterials Optics Group, Department of Optics, University of Granada, Granada, Spain
| | - Miguel Ángel Martín-Piedra
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - Miguel Alaminos
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| |
Collapse
|
4
|
Shao W, Song W, Yi J. Is oblique scanning laser ophthalmoscope applicable to human ocular optics? A feasibility study using an eye model for volumetric imaging. JOURNAL OF BIOPHOTONICS 2020; 13:e201960174. [PMID: 32101361 PMCID: PMC7278210 DOI: 10.1002/jbio.201960174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/02/2020] [Accepted: 02/22/2020] [Indexed: 05/11/2023]
Abstract
Oblique scanning laser ophthalmoscopy (oSLO) is a novel imaging modality to provide volumetric retinal imaging without depth sectioning over a large field of view (FOV). It has been successfully demonstrated in vivo in rodent eyes for volumetric fluorescein angiography (vFA). However, engineering oSLO for human retinal imaging is challenging because of the low numerical aperture (NA) of human ocular optics. To overcome this challenge, we implement optical designs to (a) increase the angle of the intermediate image under Scheimpflug condition, and (b) expand the magnification in the depth dimension with cylindrical lens to enable sufficient sampling density. In addition, we adopt a scanning-and-descaning strategy, resulting in a compact oSLO system. We experimentally show that the current setup can achieve a FOV of ~3 × 6 × 0.8 mm3 , and the transverse and axial resolutions of 7 and 41 μm, respectively. This feasibility study serves an important step for future in vivo human retinal imaging.
Collapse
Affiliation(s)
- Wenjun Shao
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
- Department of Electric and Computer Engineering, Boston University, Boston, Massachusetts
| |
Collapse
|
5
|
Ionescu AM, Chato-Astrain J, Cardona JDLC, Campos F, Pérez MM, Alaminos M, Garzón I. Evaluation of the optical and biomechanical properties of bioengineered human skin generated with fibrin-agarose biomaterials. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-16. [PMID: 32383372 PMCID: PMC7203517 DOI: 10.1117/1.jbo.25.5.055002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/24/2020] [Indexed: 05/21/2023]
Abstract
SIGNIFICANCE Recent generation of bioengineered human skin allowed the efficient treatment of patients with severe skin defects. However, the optical and biomechanical properties of these models are not known. AIM Three models of bioengineered human skin based on fibrin-agarose biomaterials (acellular, dermal skin substitutes, and complete dermoepidermal skin substitutes) were generated and analyzed. APPROACH Optical and biomechanical properties of these artificial human skin substitutes were investigated using the inverse adding-doubling method and tensile tests, respectively. RESULTS The analysis of the optical properties revealed that the model that most resembled the optical behavior of the native human skin in terms of absorption and scattering properties was the dermoepidermal human skin substitutes after 7 to 14 days in culture. The time-course evaluation of the biomechanical parameters showed that the dermoepidermal substitutes displayed significant higher values than acellular and dermal skin substitutes for all parameters analyzed and did not differ from the control skin for traction deformation, stress, and strain at fracture break. CONCLUSIONS We demonstrate the crucial role of the cells from a physical point of view, confirming that a bioengineered dermoepidermal human skin substitute based on fibrin-agarose biomaterials is able to fulfill the minimal requirements for skin transplants for future clinical use at early stages of in vitro development.
Collapse
Affiliation(s)
- Ana Maria Ionescu
- University of Granada, Laboratory of Biomaterials Optics, Department of Optics, Faculty of Sciences, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - Jesus Chato-Astrain
- University of Granada, Department of Histology, Faculty of Medicine, Tissue Engineering Group, Granada, Spain
| | - Juan de la Cruz Cardona
- University of Granada, Laboratory of Biomaterials Optics, Department of Optics, Faculty of Sciences, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - Fernando Campos
- University of Granada, Department of Histology, Faculty of Medicine, Tissue Engineering Group, Granada, Spain
| | - Maria M. Pérez
- University of Granada, Laboratory of Biomaterials Optics, Department of Optics, Faculty of Sciences, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - Miguel Alaminos
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
- University of Granada, Department of Histology, Faculty of Medicine, Tissue Engineering Group, Granada, Spain
| | - Ingrid Garzón
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
- University of Granada, Department of Histology, Faculty of Medicine, Tissue Engineering Group, Granada, Spain
| |
Collapse
|
6
|
Comparison of light propagation in dental tissues and nano-filled resin-based composite. Clin Oral Investig 2018; 23:423-433. [DOI: 10.1007/s00784-018-2451-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 04/16/2018] [Indexed: 11/27/2022]
|
7
|
Simmons ZJ, Rogers JD. Microscope objective based 4 π spectroscopic tissue scattering goniometry. BIOMEDICAL OPTICS EXPRESS 2017; 8:3828-3841. [PMID: 28856053 PMCID: PMC5560844 DOI: 10.1364/boe.8.003828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/12/2017] [Indexed: 06/07/2023]
Abstract
The measurement of optical scattering as a function of angle, goniometry, can provide a wealth of information about tissue. The goniometry technique described here measures the intensity profile at the pupil planes of two microscope objectives with a scattering sample between them. The maximum observable scattering angle is extended by employing off-axis illumination. This configuration permits several advantages including: i) rapid measurement of scattering into 4π sr to characterize the entire scattering phase function in isotropic tissue, ii) sensitivity to axially asymmetric scattering from anisotropic fibrous tissue, iii) selective interrogation of small regions within spatially inhomogenous tissue, iv) concurrent measurement of scattering coefficient μs , and v) measurement of wavelength dependent scattering properties via spectrally tunable source. The instrument is validated by comparing measurements of microsphere suspensions to the Mie scattering solution. Instrument capabilities are demonstrated with samples of rat brain and mouse eye tissues.
Collapse
Affiliation(s)
- Z. J. Simmons
- Department of Biomedical Engineering, University of Wisconsin–Madison, 1550 Engineering Drive, Madison, WI 53706,
USA
- McPherson Eye Research Institute, University of Wisconsin–Madison, 1111 Highland Avenue, WIMR 9433, Madison, WI 53705,
USA
| | - J. D. Rogers
- Department of Biomedical Engineering, University of Wisconsin–Madison, 1550 Engineering Drive, Madison, WI 53706,
USA
- McPherson Eye Research Institute, University of Wisconsin–Madison, 1111 Highland Avenue, WIMR 9433, Madison, WI 53705,
USA
| |
Collapse
|
8
|
Gonzalez-Andrades M, Cardona JDLC, Ionescu AM, Mosse CA, Brown RA. Photographic-Based Optical Evaluation of Tissues and Biomaterials Used for Corneal Surface Repair: A New Easy-Applied Method. PLoS One 2015; 10:e0142099. [PMID: 26566050 PMCID: PMC4643926 DOI: 10.1371/journal.pone.0142099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 10/16/2015] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Tissues and biomaterials used for corneal surface repair require fulfilling specific optical standards prior to implantation in the patient. However, there is not a feasible evaluation method to be applied in clinical or Good Manufacturing Practice settings. In this study, we describe and assess an innovative easy-applied photographic-based method (PBM) for measuring functional optical blurring and transparency in corneal surface grafts. METHODS Plastic compressed collagen scaffolds (PCCS) and multilayered amniotic membranes (AM) samples were optically and histologically evaluated. Transparency and image blurring measures were obtained by PBM, analyzing photographic images of a standardized band pattern taken through the samples. These measures were compared and correlated to those obtained applying the Inverse Adding-Doubling (IAD) technique, which is the gold standard method. RESULTS All the samples used for optical evaluation by PBM or IAD were histological suitable. PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD. The PBM indicated that PCCS had a transparency ratio (TR) value of 80.3 ± 2.8%, with a blurring index (BI) of 50.6 ± 4.2%. TR and BI obtained from the PBM showed a high correlation (ρ>|0.6|) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005). The AM optical properties showed that there was a largely linear relationship between the blurring and the number of amnion layers, with more layers producing greater blurring. CONCLUSIONS This innovative proposed method represents an easy-applied technique for evaluating transparency and blurriness of tissues and biomaterials used for corneal surface repair.
Collapse
Affiliation(s)
- Miguel Gonzalez-Andrades
- Tissue Repair & Engineering Centre, University College of London, London, United Kingdom
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain
- Ophthalmology Department, San Cecilio University Hospital, Granada, Spain
- * E-mail:
| | - Juan de la Cruz Cardona
- Laboratory of Biomaterials and Optics—Optics Department, University of Granada, Granada, Spain
| | - Ana Maria Ionescu
- Laboratory of Biomaterials and Optics—Optics Department, University of Granada, Granada, Spain
| | - Charles A. Mosse
- Optics Department, University College of London, London, United Kingdom
| | - Robert A. Brown
- Tissue Repair & Engineering Centre, University College of London, London, United Kingdom
| |
Collapse
|
9
|
Akimov NP, Marshak DW, Frishman LJ, Glickman RD, Yusupov RG. Histamine reduces flash sensitivity of on ganglion cells in the primate retina. Invest Ophthalmol Vis Sci 2010; 51:3825-34. [PMID: 20207974 DOI: 10.1167/iovs.09-4806] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE. In Old World primates, the retina receives input from histaminergic neurons in the posterior hypothalamus. They are a subset of the neurons that project throughout the central nervous system and fire maximally during the day. The contribution of these neurons to vision, was examined by applying histamine to a dark-adapted, superfused baboon eye cup preparation while making extracellular recordings from peripheral retinal ganglion cells. METHODS. The stimuli were 5-ms, 560-nm, weak, full-field flashes in the low scotopic range. Ganglion cells with sustained and transient ON responses and two cell types with OFF responses were distinguished; their responses were recorded with a 16-channel microelectrode array. RESULTS. Low micromolar doses of histamine decreased the rate of maintained firing and the light sensitivity of ON ganglion cells. Both sustained and transient ON cells responded similarly to histamine. There were no statistically significant effects of histamine in a more limited study of OFF ganglion cells. The response latencies of ON cells were approximately 5 ms slower, on average, when histamine was present. Histamine also reduced the signal-to-noise ratio of ON cells, particularly in those cells with a histamine-induced increase in maintained activity. CONCLUSIONS. A major action of histamine released from retinopetal axons under dark-adapted conditions, when rod signals dominate the response, is to reduce the sensitivity of ON ganglion cells to light flashes. These findings may relate to reports that humans are less sensitive to light stimuli in the scotopic range during the day, when histamine release in the retina is expected to be at its maximum.
Collapse
Affiliation(s)
- Nikolay P Akimov
- Departments of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA
| | | | | | | | | |
Collapse
|
10
|
Optical absorption and scattering of bovine cornea, lens and retina in the visible region. Lasers Med Sci 2009; 24:839-47. [PMID: 19495828 DOI: 10.1007/s10103-009-0677-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
Optical properties of bovine ocular tissues were determined at laser wavelengths in the visible region. The inverse adding doubling (IAD), Kubelka-Munk (KM), and inverse Monte Carlo (IMC) methods were applied to the measured values of the total diffuse transmission, total diffuse reflection, and collimated transmission to determine the optical absorption and scattering coefficients of the bovine cornea, lens and retina at 457.9 nm, 488 nm, and 514.5 nm laser lines from an argon ion laser. The optical properties obtained from these three methods were compared, and their validity is discussed.
Collapse
|
11
|
Ao H, Xing D, Wei H, Gu H, Wu G, Lu J. Thermal coagulation-induced changes of the optical properties of normal and adenomatous human colon tissues in vitro in the spectral range 400-1,100 nm. Phys Med Biol 2008; 53:2197-206. [PMID: 18385526 DOI: 10.1088/0031-9155/53/8/013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The absorption coefficients, the reduced scattering coefficients and the optical penetration depths for native and coagulated human normal and adenomatous colon tissues in vitro were determined over the range of 400-1,100 nm using a spectrophotometer with an internal integrating sphere system, and the inverse adding-doubling method was applied to calculate the tissue optical properties from diffuse reflectance and total transmittance measurements. The experimental results showed that in the range of 400-1,100 nm there were larger absorption coefficients (P < 0.01) and smaller reduced scattering coefficients (P < 0.01) for adenomatous colon tissues than for normal colon tissues, and there were smaller optical penetration depths for adenomatous colon tissues than for normal colon tissues, especially in the near-infrared wavelength. Thermal coagulation induced significant increase of the absorption coefficients and reduced scattering coefficients for the normal and adenomatous colon tissues, and significantly reduced decrease of the optical penetration depths for the normal and adenomatous colon tissues. The smaller optical penetration depth for coagulated adenomatous colon tissues is a disadvantage for laser-induced thermotherapy (LITT) and photodynamic therapy (PDT). It is necessary to adjust the application parameters of lasers to achieve optimal therapy.
Collapse
Affiliation(s)
- Huilan Ao
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, ina Normal University, Guangzhou 510631, People's Republic of China
| | | | | | | | | | | |
Collapse
|