A Model-based approach for microvasculature structure distortion correction in two-photon fluorescence microscopy images.

This paper investigates a postprocessing approach to correct spatial distortion in two-photon fluorescence microscopy images for vascular network reconstruction. It is aimed at in vivo imaging of large field-of-view, deep-tissue studies of vascular structures. Based on simple geometric modelling of the object-of-interest, a distortion function is directly estimated from the image volume by deconvolution analysis. Such distortion function is then applied to subvolumes of the image stack to adaptively adjust for spatially varying distortion and reduce the image blurring through blind deconvolution. The proposed technique was first evaluated in phantom imaging of fluorescent microspheres that are comparable in size to the underlying capillary vascular structures. The effectiveness of restoring three-dimensional (3D) spherical geometry of the microspheres using the estimated distortion function was compared with empirically measured point-spread function. Next, the proposed approach was applied to in vivo vascular imaging of mouse skeletal muscle to reduce the image distortion of the capillary structures. We show that the proposed method effectively improve the image quality and reduce spatially varying distortion that occurs in large field-of-view deep-tissue vascular dataset. The proposed method will help in qualitative interpretation and quantitative analysis of vascular structures from fluorescence microscopy images.

In vivo microscopy reveals extensive embedding of capillaries within the sarcolemma of skeletal muscle fibers.

OBJECTIVE: To provide insight into mitochondrial function in vivo, we evaluated the 3D spatial relationship between capillaries, mitochondria, and muscle fibers in live mice. METHODS: 3D volumes of in vivo murine TA muscles were imaged by MPM. Muscle fiber type, mitochondrial distribution, number of capillaries, and capillary-to-fiber contact were assessed. The role of Mb-facilitated diffusion was examined in Mb KO mice. Distribution of GLUT4 was also evaluated in the context of the capillary and mitochondrial network. RESULTS: MPM revealed that 43.6 ± 3.3% of oxidative fiber capillaries had ≥50% of their circumference embedded in a groove in the sarcolemma, in vivo. Embedded capillaries were tightly associated with dense mitochondrial populations lateral to capillary grooves and nearly absent below the groove. Mitochondrial distribution, number of embedded capillaries, and capillary-to-fiber contact were proportional to fiber oxidative capacity and unaffected by Mb KO. GLUT4 did not preferentially localize to embedded capillaries. CONCLUSIONS: Embedding capillaries in the sarcolemma may provide a regulatory mechanism to optimize delivery of oxygen to heterogeneous groups of muscle fibers. We hypothesize that mitochondria locate to PV regions due to myofibril voids created by embedded capillaries, not to enhance the delivery of oxygen to the mitochondria.

Highly stable, substrate-free, and flexible broadband halide perovskite paper photodetectors.

In this work, we aim to fabricate a highly stable and flexible perovskite paper photodetector based on a Zn-doped MA0.6FA0.4PbI3 perovskite and CNC. The paper photodetector has been successfully synthesized by the vacuum filtration method and deposited with interdigitated electrodes. The paper photodetector exhibits a significant photoresponse with a responsivity of 0.23 A W-1 under 650 nm light irradiation when operated at 5 V. The stability of the paper photodetector has also been tested and it shows high photoresponse after 30 days under ambient conditions. Therefore, this paper photodetector holds promise for developing efficient, stable, and flexible optoelectronic devices in the future.

Ultrasound Biomicroscopic Diagnosis of Angle-closure Mechanisms in Vietnamese Subjects With Unilateral Angle-closure Glaucoma.

OBJECTIVE: To identify the mechanisms of angle closure in the fellow eyes of Vietnamese subjects with unilateral primary angle-closure glaucoma (PACG) using ultrasound biomicroscopy (UBM) before and after prophylactic laser peripheral iridotomy (LPI). DESIGN: This is a prospective observational study. PARTICIPANTS: Patients diagnosed with PACG in one eye and primary angle-closure suspect (PACS) in the other eye were included in this study, conducted from January 2014 to October 2014 at Vietnam National Institute of Ophthalmology. MATERIALS AND METHODS: A total of 112 PACS fellow eyes of 112 patients presenting with unilateral PACG were evaluated. All subjects underwent standard ophthalmic clinical examination and UBM imaging a week before and after LPI. On the basis of UBM images, the angle-closure mechanism was defined according to the classification of Svend Vedel Kessing and John Thygesen as pupillary block (PB), plateau iris (PI), and mixed pattern. RESULTS: The proportion of PACS subjects who showed PB was 86.6%, while 13.4% showed a PI configuration before LPI. After LPI the pre-LPI PB group was reclassified, with 55.4% showing pure PB, and 31.3% showing mixed mechanisms (PB and PI). The proportion of patients with PI remained unchanged (13.4%) even after LPI. After the LPI, the angle opening significantly increased in the PB subgroup (14.01±2.43 degrees, P<0.01) and reclassified mixed group (6.34±1.71 degrees, P<0.01) but remained almost unchanged in the PI group (1.81±0.98 degrees, P>0.05). CONCLUSION: On the basis of the UBM criteria, PI was found in 13.4% of PACS fellow eyes of Vietnamese subjects with PACG. The clinical and UBM features of patients showing PI before LPI remained almost unchanged after the procedure. The proportion of patients showing PB pre-LPI reduced from 86.6% to 55.4% showing the important role of mixed mechanisms in PACG.

Study of the development of the mouse thoracic aorta three-dimensional macromolecular structure using two-photon microscopy.

Using the intrinsic optical properties of collagen and elastin, two-photon microscopy was applied to evaluate the three-dimensional (3D) macromolecular structural development of the mouse thoracic aorta from birth to 60 days old. Baseline development was established in the Scavenger Receptor Class B Type I-Deficient, Hypomorphic Apolipoprotein ER61 (SR-BI KO/ApoeR61(h/h)) mouse in preparation for modeling atherosclerosis. Precise dissection enabled direct observation of the artery wall in situ. En-face, optical sectioning of the aorta provided a novel assessment of the macromolecular structural development. During aortic development, the undulating lamellar elastin layers compressed consistent with the increases in mean aortic pressure with age. In parallel, a net increase in overall wall thickness (p<0.05, in day 60 compared with day 1 mice) occurred with age whereas the ratio of the tunicas adventitia and media to full aortic thickness remained nearly constant across age groups (~1:2.6, respectively). Histochemical analyses by brightfield microscopy and ultrastructure validated structural proteins and lipid deposition findings derived from two-photon microscopy. Development was associated with decreased decorin but not biglycan proteoglycan expression. This non-destructive 3D in situ approach revealed the aortic wall microstructure development. Coupling this approach with the intrinsic optical properties of the macromolecules may provide unique vascular wall 3D structure in many pathological conditions, including aortic atherosclerosis, dissections and aneurysms.