Stable and simple quantitative phase-contrast imaging by Fresnel biprism

Digital holographic (DH) microscopy has grown into a powerful nondestructive technique for the real-time study of living cells including dynamic membrane changes and cell fluctuations in nanometer and sub-nanometer scales. The conventional DH microscopy configurations require a separately generated coherent reference wave that results in a low phase stability and a necessity to precisely adjust the intensity ratio between two overlapping beams. In this work, we present a compact, simple, and very stable common-path DH microscope, employing a self-referencing configuration. The microscope is implemented by a diode laser as the source and a Fresnel biprism for splitting and recombining the beams simultaneously. In the overlapping area, linear interference fringes with high contrast are produced. The frequency of the interference pattern could be easily adjusted by displacement of the biprism along the optical axis without a decrease in fringe contrast. To evaluate the validity of the method, the spatial noise and temporal stability of the setup are compared with the common off-axis DH microscope based on a Mach-Zehnder interferometer. It is shown that the proposed technique has low mechanical noise as well as superb temporal stability with sub-nanometer precision without any external vibration isolation. The higher temporal stability improves the capabilities of the microscope for studying micro-object fluctuations, particularly in the case of biological specimens. Experimental results are presented using red blood cells and silica microspheres to demonstrate the system performance

Solar photodegradation of carbamazepine from aqueous solutions using a compound parabolic concentrator equipped with a sun tracking system

The primary purpose of this study was to investigate the efficiency of a Compound Parabolic Concentrator (CPC) equipped with a sun tracking system in the photolysis of carbamazepine as a refractory organic compound. The natural sunlight experiments were accomplished during the period May–July 2017 in Tehran, Iran. The intermediate by-products of the process of solar photodegradation of carbamazepine (CBZ) were characterized using LC–MS. The results showed that increasing the reactor temperature did not significantly change CBZ degradation efficiency. However, the solution pH played a comparatively important role in CBZ solar photo degradation: removal efficiency increased considerably with pH from about 49% at pH 7 to almost 61% at pH 9. According to our findings, using a CPC reactor equipped with a sun tracker system promotes the solar photo-transformation rate of CBZ by 2-3 fold. In addition, LC/MS analysis showed that eight main intermediates were formed in the treated solution after solar photodegradation of CBZ. Therefore, complete mineralization of CBZ was not accomplished

Common-path, single-shot phase-shifting digital holographic microscopy using a Ronchi ruling

Phase-shifting digital holography is widely considered to be a groundbreaking method to quantitatively investigate the phase distribution of specimens, such as living cells. The main flaws of this method, however, are that the requirement for several sequential phase-shifted holograms eliminates the possibility of single-shot imaging and complex configurations would also increase the temporal noise. The present paper aims to validate a single-shot, common-path, phase-shifting digital holographic microscopy, employing a self-referencing geometry. A Ronchi ruling, located in the Fourier plane of a standard microscopic imaging system, produces multiple replicas of sample information in the image plane. The phase retrieval algorithm is performed by superposition of the sample-free portion of each replica with the object information, and requires at least three adjacent diffraction orders. To evaluate the performance of the proposed method, the phase distribution of silica microspheres as a test sample and the morphology of red blood cells as a biological specimen are determined. This configuration offers improved temporal stability in comparison with previously reported Mach-Zehnder interferometers, and may serve as an alternative for real-time surveying of nanometric and subnanometric fluctuations of living microscopic specimens

Exploring Intercellular Dynamics: Ultra-Weak Biophoton Emission as a Novel Indicator of Altered Cell Functions and Disease in Oligospermia Mice: Ultraweak photon emission and disrupt the normal pattern of testicular cells

Introduction: Biophoton emission, the spontaneous release of photons from living cells, has emerged as an attractive field of research in the study of biological systems. Scientists have recently discovered that changes in biophoton emission could serve as potential indicators of pathological conditions. This intriguing phenomenon suggests that cells might communicate and interact with each other through the exchange of these faint but significant light signals. Therefore, the present study introduces intercellular relationships with biophoton release to detect normal and abnormal cell functions to further achieve cellular interactions by focusing on cell and cell arrangement in disease conditions.Methods: Twenty male mice were assigned to control and busulfan groups. Five weeks after the injection of busulfan, the testis was removed, and then the stereological techniques and TUNEL assay were applied to estimate the histopathology of the testis tissue sections.Results: The findings revealed that the ultra-weak biophoton emission in the control group was significantly lower than in the busulfan group. The oligospermia mice model showed that it significantly changed the spatial arrangement of testicular cells and notably decreased the testis volume, length of seminiferous tubules, and the number of testicular cells. The results of the TUNEL assay showed that the percentage of apoptotic cells significantly increased in the busulfan group.Conclusion: The ultra-weak biophoton emission from testis tissue was reduced in oligospermia mice. As a result, the decline of ultra-weak biophoton can indicate a change in cell arrangement, a decrease in intercellular interaction, and eventually disease