The Physicochemical Attributes, Volatile Compounds, and Antioxidant Activities of Five Plum Cultivars in Sichuan.

Plum (Prunus salicina Lindl.) is an important stone fruit crop in Sichuan that is increasingly in demand by consumers owing to its flavor and outstanding nutraceutical properties. The physicochemical characteristics, antioxidant capacity, and volatile profiles of five traditional and new plum cultivars in Sichuan were determined using high-performance liquid chromatography and gas chromatography time-of-flight mass spectrometry. The results showed that all plums exhibited an appropriate quality profile for fresh consumption; the new cultivar 'ZH' exhibited the highest soluble solids content, sugar-acid ratio, total phenolic content, total flavonoid content, and antioxidant capacity. High sugar-low acid properties were observed in five plum cultivars. Sucrose was the main sugar, while quinic acid and malic acid were the main organic acids. The plums were rich in volatile compounds and had specific volatile characteristics. A total of 737 volatiles were identified in the plum fruit, and orthogonal partial least-squares discriminant analysis was employed to screen 40 differential volatiles as markers for cultivar distinction. These findings offer comprehensive information on the physicochemical characteristics, antioxidant capacity, and volatile profiles of plums.

Shear wave elastography can stratify rectal cancer response to short-course radiation therapy.

Rectal cancer is a deadly disease typically treated using neoadjuvant chemoradiotherapy followed by total mesorectal excision surgery. To reduce the occurrence of mesorectal excision surgery for patients whose tumors regress from the neoadjuvant therapy alone, conventional imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), is used to assess tumor response to neoadjuvant therapy before surgery. In this work, we hypothesize that shear wave elastography offers valuable insights into tumor response to short-course radiation therapy (SCRT)-information that could help distinguish radiation-responsive from radiation-non-responsive tumors and shed light on changes in the tumor microenvironment that may affect radiation response. To test this hypothesis, we performed elastographic imaging on murine rectal tumors (n = 32) on days 6, 10, 12, 16, 18, 20, 23, and 25 post-tumor cell injection. The study revealed that radiation-responsive and non-radiation-responsive tumors had different mechanical properties. Specifically, radiation-non-responsive tumors showed significantly higher shear wave speed SWS (p < 0.01) than radiation-responsive tumors 11 days after SCRT. Furthermore, there was a significant difference in shear wave attenuation (SWA) (p < 0.01) in radiation-non-responsive tumors 16 days after SCRT compared to SWA measured just one day after SCRT. These results demonstrate the potential of shear wave elastography to provide valuable insights into tumor response to SCRT and aid in exploring the underlying biology that drives tumors' responses to radiation.

Inhibition of Perilla frutescens Essential Oil on Pellicle Formation of Candida tropicalis and Pichia kluyveri and Its Effect on Volatile Compounds in Sichuan Pickles.

Pellicle formation is the most typical characteristic of deteriorating fermented vegetable products. Perilla frutescens essential oil (PEO) is widely used as a useful natural preservative. However, few studies have addressed the antifungal activity and mechanism of PEO in pellicle formation microorganisms, and it is still unclear whether it can inhibit pellicle formation and affect its volatile compounds in Sichuan pickles. The current study showed that PEO can inhibit pellicle formation during fermentation of Sichuan pickles as it had significant antifungal activity against the pellicle formation microorganisms Candida tropicalis SH1 and Pichia kluyveri SH2. The minimum inhibitory concentration (MIC) of PEO against C. tropicalis SH1 and P. kluyveri SH2 was determined to be 0.4 µL/mL, and the minimum fungicidal concentrations (MFCs) were 1.6 µL/mL and 0.8 µL/mL, respectively. The antifungal mechanism was activated as a result of damage to the cell membrane, an increase in the cell permeability, a decrease in the mitochondrial membrane potential, and the inhibition of ATPase activity. Meanwhile, the addition of PEO to Sichuan pickles can enrich the profiles of volatile compounds during fermentation, including limonene, myrcene, 1,8-cineole, linalool, perilla ketone, heptanal, hexanal, α-thujone and ß-terpineol and thus improve the overall sensory acceptability. These results indicated that PEO has the potential to be used as a novel food preservative to control pellicle formation in fermented vegetables.

Single-wavelength, single-shot pulse oximetry using an LED-generated vector beam.

Photoplethysmography (PPG) is an optical technique that monitors blood oxygen saturation levels, typically with the use of pulse oximeters. Conventional pulse oximetry estimates the ratio of light absorbed at two wavelengths. Attempts have been made to improve the precision of these measurements by using polarized light, with the tradeoff of requiring multiple sequential measurements. We demonstrate a novel PPG technique that uses radially polarized light generated by a light-emitting diode (LED) to obtain single-shot, blood oxygen-saturation measurements using a single wavelength at a rate of 50 fps. Our work, to the best of our knowledge, presents both a novel use of a vector beam and a first demonstration of vector-beam generation using LEDs.

Demonstration of speckle resistance using space-time light sheets.

The capacity of self-healing fields to reconstruct after passing through scattering media may prove useful in reducing speckle formation. Here, we study the speckle response of the space-time (ST) light sheet compared to a Gaussian wave packet, Airy beam, and Bessel Gauss beam. We find that the Pearson's correlation coefficient for the ST light sheet is 50%, 48% and 40% larger than that of the Gaussian, Airy beam and Bessel Gauss beams, respectively, demonstrating a strong correlation to an input beam that has not been speckled. These results suggest that the ST light sheet exhibits considerable resistance to speckle generation. We also investigate the speckle response of the ST light sheet at its second-harmonic frequency and observe a mean Pearson's correlation coefficient close to 0.6, comparable to the second-harmonic Bessel Gauss beam, and 2.8 × the value obtained for the second-harmonic Gaussian beam. Our results lend themselves to a variety of applications including bioimaging, communications, and optical tweezers.

Label-retention expansion microscopy.

Expansion microscopy (ExM) increases the effective resolving power of any microscope by expanding the sample with swellable hydrogel. Since its invention, ExM has been successfully applied to a wide range of cell, tissue, and animal samples. Still, fluorescence signal loss during polymerization and digestion limits molecular-scale imaging using ExM. Here, we report the development of label-retention ExM (LR-ExM) with a set of trifunctional anchors that not only prevent signal loss but also enable high-efficiency labeling using SNAP and CLIP tags. We have demonstrated multicolor LR-ExM for a variety of subcellular structures. Combining LR-ExM with superresolution stochastic optical reconstruction microscopy (STORM), we have achieved molecular resolution in the visualization of polyhedral lattice of clathrin-coated pits in situ.

Quantitative Classification of 3D Collagen Fiber Organization From Volumetric Images.

Collagen fibers in biological tissues have a complex 3D organization containing rich information linked to tissue mechanical properties and are affected by mutations that lead to diseases. Quantitative assessment of this 3D collagen fiber organization could help to develop reliable biomechanical models and understand tissue structure-function relationships, which impact diagnosis and treatment of diseases or injuries. While there are advanced techniques for imaging collagen fibers, published methods for quantifying 3D collagen fiber organization have been sparse and give limited structural information which cannot distinguish a wide range of 3D organizations. In this article, we demonstrate an algorithm for quantitative classification of 3D collagen fiber organization. The algorithm first simulates five groups, or classifications, of fiber organization: unidirectional, crimped, disordered, two-fiber family, and helical. These five groups are widespread in natural tissues and are known to affect the tissue's mechanical properties. We use quantitative metrics based on features such as preferred 3D fiber orientation and spherical variance to differentiate each classification in a repeatable manner. We validate our algorithm by applying it to second-harmonic generation images of collagen fibers in tendon and cervix tissue that has been sectioned in specified orientations, and we find strong agreement between classification from simulated data and the physical fiber organization. Our approach provides insight for interpreting 3D fiber organization directly from volumetric images. This algorithm could be applied to other fiber-like structures that are not necessarily made of collagen.

Expansion enhanced nanoscopy.

The advance of optical super-resolution fluorescence microscopy has revolutionized our vision of the subcellular world. Further improvement in the spatial resolution is of great significance for structural and functional investigations. The recently developed expansion microscopy (ExM), which achieves sub-diffraction imaging via physical expansion of the sample, provides a great opportunity for further resolution enhancement of existing optical super-resolution techniques. However, although such combination seems apparent, several technical obstacles, especially the dramatic loss of fluorescence signal during ExM sample preparation, have hampered this goal. In this work, aiming at this challenge, we have developed new strategies to retain and increase the fluorescence of the expanded sample. With the new labeling methods, we have successfully made the labeling density of expanded samples sufficing the Nyquist sampling criteria for optical super-resolution imaging, such as stimulated emission depletion microscopy (STED) and super-resolution optical fluctuation imaging (SOFI). The newly developed expansion nanoscopic imaging (ExN) approaches, i.e. ExSTED and ExSOFI, demonstrated up to 4-fold resolution enhancement compared to standard STED and SOFI, providing a simple and effective way to realize high resolution imaging both at the cellular and tissue level.