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The article presents an illegal drug detector that utilizes photonic crystal fiber (PCF). The fiber structure of the H-PCF comprises a dodecagonal core and circular air gaps in cladding areas. We have analyzed the designed terahertz (THz) frequency range utilizing the Finite Element Method (FEM) and the COMSOL Multiphysics application. The revised design has a high sensitivity in detecting amphetamine (n = 1.518) and cocaine (n = 1.5022) at a frequency of 3 THz, via detection rates of 99.43% and 99.20%, correspondingly. Furthermore, the suggested fiber, which operates at a frequency of 3 THz, has a relatively tiny confinement loss of 4.93×10-08 dB/m and 6.16×10-09 dB/m and a minimal effective material loss of construction of 0.0032 cm-1. In conclusion, it may be stated that drug misuse not only leads to immediate repercussions but also has severe and enduring impacts on human health, potentially resulting in fatality. Hence, it is imperative to accurately and effectively detect illicit substances. H-PCF architecture we offered is well-suited to detect illegal drugs. Doi: 10.28991/ESJ-2024-08-06-020 Full Text: PDF

This model introduced an innovative hollow-core optical waveguide with an octagonal core, specifically designed for rapid detection of various food oil contaminations is founded on the principles of Photonic Crystal Fiber (PCF). By analyzing the refractive index (RI) variations between pure and contaminated oil, we evaluate other essential optical parameters. The characteristics inherent to the suggested food oil sensor are examined using COMSOL Multiphysics v6.1, employing the Finite Element Method (FEM). Highly precise mesh components are included to provide optimal simulation accuracy. The outcomes from the suggested sensor model demonstrate exceptionally strong relative sensitivity of 98.52 % for castor oil, 98.46 % for sunflower oil, 98.41 % for mustard oil, 98.32 % for olive oil, and 98.03 % for coconut oil, all measured at 2 THz. Additionally, the simulation shows a very low confinement loss of 2.37 × 10−12 cm-1, a numerical aperture of 0.242, effective area of 1.1459 × 10–7 m², and effective material loss of 0.0038 cm-1 for castor oil under optimal structural circumstances. The straightforward design of the PCF in the sensor indicates that it can be implemented with ease, given these standard performance indicators. Therefore, it is anticipated that this sensor will open improved avenues for detection and identification of several distinct food oil contaminations. It can be produced using standard fabrication processes.

In this article, an advanced-level type of Photonic Crystal Fiber (PCF) sensor, having a flower shape core with a unique hexagonal cladding, is proposed. Performance for detecting is evaluated in various animal's milk, such as camel, cow, and buffalo milk, with the suggested PCF sensor. The maximum Relative Sensitivities (RS) of the PCF sensor are 88.2 %, 88.5 %, and 88.8 % for detecting camel milk, cow milk, and buffalo milk, respectively. Moreover, it has a negligible Confinement Loss (CL) of 2.04018402 × 10−14 dB/m and Total Loss (TL) of 2.1520000 × 10−01 dB/m and Effective Material Loss (EML) of 0.21520 cm−1. Since Milk is as great source of nutrients such as Calcium, Vitamin D, Vitamin B12, Phosphorus and Protein. The nutrient composition of different animals' milks and their respective quantities are determined by set values at the beginning and differ among the types of milk. As all of them hold the same tone, it becomes challenging to identify them. Our suggested PCF sensor comes with its remarkable detection capacity to identify them. Therefore, the use of suggested PCF sensor will be helpful for both the industry and consumers. For the industry, it aids in ensuring the quality and composition of animal milk. For consumers, it means they can trust that the milk they purchase has been accurately tested and verified for its nutrient content and safety. With the implementation of the PCF sensor, the industry can better ensure the quality and authenticity of animal milk, reducing the risk of fraud and helping consumers make more informed choices about the milk they consume. This contributes to better assurance of proper nutrient intake.

Cyanide is very poisonous and raises environmental problems because of its industrial application and potential as a terrorist weapon. Given CN's toxicity and possible hazard to people, an effective and adaptive detection approach is needed. This specification suggests using a PCF to build a terahertz Hexagonal Core and Curved rectangular air holes sensor to detect NaCN and KCN. The recently created PCF analysis, which was promptly delivered, reveals an RS concentration of 99.62 % for NaCN and a maximum concentration of KCN is 99.08 %. In addition, we analyzed the Confinement Loss (CL) at a value of 5.88 × 10−09 dB/m and 2.07 × 10−05 dB/m, as well as EML at values of 0.0020 cm−1 and 0.0026 cm−1, accordingly, about these hazardous substances. The designed detector can identify NaCN and KCN at low concentrations even with small RI shifts due to its high sensitivity. Real-time NaCN and KCN detection and monitoring through nerve reflexes is essential for life-threatening conditions. It can selectively work in NaCN and KCN, ensuring accurate detection even in complex chemical compositions. Additionally, its tiny size allows for emergency use.

Ethanol and Benzene are two compounds constitute two different chemicals with unique properties and compositions. The adopted material describes a state-of-the-art Photonic Crystal Fiber (PCF) containing an unusual hexagon covering an unparalleled web-like core. A greater estimated performance for our PCF monitor is the limit utilization of the above variables, benzene, and ethanol as dangerous chemicals. The newly developed PCF analysis, which was immediately presented out, exposes a most RS, specifically 95.21% as well as a 94.67% maximum benzene plus ethanol. Additionally, we examined Confinement Loss (CL) about 4.674 × 10−3 dB/m, 1.378 × 10−2 dB/m, plus Effective Material Loss (EML) about 0.0078 cm-1, 0.0083 cm−1 related to these harmful chemicals. For to their intense responsiveness, designed detector simplifies identifying benzene as well as ethanol at the trace level if even slight shifts in the RI are detected. Nervous reactions allow swiftly tracking the level of ethanol and benzene in, almost, real-time, which is critical for immediate measures when in a life-threatening situation. They can be targeted very particularly to attract only to ethanol and benzene, so, detection, even in the existence of quite complex chemical records, is precise. Additionally, due to its smallness, it can be applied in emergencies. [ABSTRACT FROM AUTHOR]

Cyanide is very poisonous and raises environmental problems because of its industrial application and potential as a terrorist weapon. Given CN's toxicity and possible hazard to people, an effective and adaptive detection approach is needed. This specification suggests using a PCF to build a terahertz Hexagonal Core and Curved rectangular air holes sensor to detect NaCN and KCN. The recently created PCF analysis, which was promptly delivered, reveals an RS concentration of 99.62 % for NaCN and a maximum concentration of KCN is 99.08 %. In addition, we analyzed the Confinement Loss (CL) at a value of 5.88 × 10 -09  dB/m and 2.07 × 10 -05  dB/m, as well as EML at values of 0.0020 cm -1 and 0.0026 cm -1 , accordingly, about these hazardous substances. The designed detector can identify NaCN and KCN at low concentrations even with small RI shifts due to its high sensitivity. Real-time NaCN and KCN detection and monitoring through nerve reflexes is essential for life-threatening conditions. It can selectively work in NaCN and KCN, ensuring accurate detection even in complex chemical compositions. Additionally, its tiny size allows for emergency use., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

This work is to investigate the instrumentation implementing issues of back focal plane (BFP)-typed apertometer. Firstly, we introduce a general instrument architecture of the BFP-typed apertometer, including the hardware (optics and mechanics) of the system, operation procedures of control and measurement system, and also the digital image processing algorithm/software. Secondly, we are the first to discuss the gradual rising effect of total-internal-reflection (TIR) phenomenon, the criteria on how to “exactly” locate the reference ring on BFP images, and the corresponding accuracies. As a significantly important complement, we further discuss three important issues: 1) the influence of Goos–Hänchen shift on numerical aperture (NA) measurement; 2) comparison of one-dimension and two-dimension identification algorithms; and 3) comparison of center locating using Fourier correlation analysis (FCA) and Hough transformation (HT) algorithms. [ABSTRACT FROM AUTHOR]

A solid immersion objective is generally composed of a truncated solid ball and a commercial objective lens. It features higher numerical aperture (NA) than oil-immersion objectives and thus shows capabilities in some applications requiring higher NA or spatial resolutions. Different from commercial products of oil-immersion objectives and their pre labeled NA values, solid immersion objective is generally home-designed/developed, and the theoretical NA is taken as its practical value, which is not suggested. So far, there has been no proper and commercial apparatus to measure this NA value especially for bare solid immersion objectives. In this work, we propose an extremely simple but very practical approach for the measurement, which inherits the concept of Fourier optics but offers some specific features. Furthermore, we specifically propose an algorithm of multipoint reference to achieve high accuracy of NA value. Detailed comparisons between the proposed algorithm and the previous algorithm of single-point reference are elaborated. An experimental prototype of apertometer for solid immersion objective is built up to verify the proposed approach and algorithm. To the best of the authors’ knowledge, this is the simplest, cheapest, and most practical approach and apparatus for the NA measurement of bare solid immersion objective. [ABSTRACT FROM AUTHOR]

We present an endlessly single-mode, bend-insensitive and highly birefringent photonic crystal fibre (PCF) for efficient wave transmission in the terahertz (THz) spectrum. To facilitate flat dispersion and high birefringence, a diamond-shaped porous core is introduced inside the Zeonex (background material)-based hexagonal porous cladding. Moreover, the dense geometrical arrangement of the regular hexagonal lattice in the cladding region holds maximum usable optical power inside the porous core. The major geometrical parameter of the proposed PCF such as core porosity has been optimized to improve the optical guiding parameters. The numerically investigated outcomes have shown an ultrahigh birefringence and numerical aperture of 0.0888 and 0.57, respectively. Apart from this, very low bending and material losses of 3.01 × 10 - 20 cm−1 and 0.01451 cm−1 with flattened dispersion variation of ± 0.2463 ps/THz/cm have been achieved over the broad THz band (i.e. 0.8–1.3 THz). Additionally, our proposed PCF sustains endlessly single-mode operation with a very high core power fraction of 75.28%. With all these promising results, the proposed PCF would be a potential candidate for polarization preserving as well as for efficient broadband transmission applications in the THz regime. [ABSTRACT FROM AUTHOR]

Abstract: Notch4 is a divergent member of the Notch family of receptors that is primarily expressed in the vasculature. Its expression implies an important role for Notch4 in the vasculature; however, mice homozygous for the Notch4d1 knockout allele are viable. Since little is known about the role of Notch4 in the vasculature and how it functions, we further investigated Notch4 in mice and in cultured cells. We found that the Notch4d1 allele is not null as it expresses a truncated transcript encoding most of the NOTCH4 extracellular domain. In cultured cells, NOTCH4 did not signal in response to ligand. Moreover, NOTCH4 inhibited signalling from the NOTCH1 receptor. This is the first report of cis-inhibition of signalling by another Notch receptor. The NOTCH4 extracellular domain also inhibits NOTCH1 signalling when expressed in cis, raising the possibility that reported Notch4 phenotypes may not be due to loss of NOTCH4 function. To better address the role of NOTCH4 in vivo, we generated a Notch4 null mouse in which the entire coding region was deleted. Notch4 null mice exhibited slightly delayed vessel growth in the retina, consistent with our novel finding that NOTCH4 protein is expressed in the newly formed vasculature. These findings indicate a role of NOTCH4 in fine-tuning the forming vascular plexus. [Copyright &y& Elsevier]

Abstract: A novel cryogenic optical-microscope system was developed in which the objective lens is set inside of the cryostat adiabatic vacuum space. Being isolated from the sample when it was cooled, the objective lens was maintained at room temperature during the cryogenic measurement. Therefore, the authors were able to use a color-aberration corrected objective lens with a numerical aperture of 0.9. The lens is equipped with an air vent for compatibility to the vacuum. The theoretically expected spatial resolutions of 0.39μm along the lateral direction and 1.3μm along the axial direction were achieved by the developed system. The system was applied to the observations of non-uniform distributions of the photosystems in the cells of a green alga, Chlamydomonas reinhardtii, at 94K. Gaussian decomposition analysis of the fluorescence spectra at all the pixels clearly demonstrated a non-uniform distribution of the two photosystems, as reflected in the variable ratios of the fluorescence intensities assigned to photosystem II and to those assigned to photosystem I. The system was also applied to the fluorescence spectroscopy of single isolated photosystem I complexes at 90K. The fluorescence, assigned to be emitted from a single photosystem I trimer, showed an intermittent fluctuation called blinking, which is typical for a fluorescence signal from a single molecule. The vibronic fluorescence bands at around 790nm were observed for single photosystem I trimers, suggesting that the color aberration is not serious up to the 800nm spectral region. [Copyright &y& Elsevier]