Low loss and low dispersion hybrid core photonic crystal fiber for terahertz propagation

In this paper, a hybrid-core circular cladded photonic crystal fiber is designed and analyzed for application in the terahertz frequency range. We introduce a rectangular structure in addition to a conventional hexagonal structure in the core to reduce the material absorption loss. The modal characteristics of the fiber have been investigated using full vector finite element method. Simulated results exhibit an ultra-low effective material loss of 0.035 cm\(^{-1}\) and ultra-flattened dispersion of 0.07 ps/THz/cm. Some other important fiber characteristics suitable for terahertz signal transmission including confinement loss, core power fraction, effective area and single-mode conditions of the fiber have also been investigated. In order to simplify design and facilitate fabrication, only circular shaped air holes have been employed. Due to its promising characteristics, the proposed waveguide may provide efficient transmission of broadband terahertz signals.     

An assessment of the protein quality and vitamin b content of commonly used fermented products of legumes and millets

Fermented products of legumes, Bengal gram dhal (Cicer arietinum) and green gram dhal (Phaseolus aureus), and millets, bajra (Pennisetum typhoideum), jowar (Sorghum vulgare) and ragi (Eleucine coracana), were analysed for protein quality and vitamin B content. Fermentation reduced total crude protein by 6-8 % in the legume products and 4-6% in the millet products of bajra and ragi. No reduction in crude protein was observed in fermented jowar products. Temperature of batters increased considerably on fermentation, while pH decreased. The protein efficiency ratio (PER) and the true digestibility (TD) of legume products were not altered by fermentation, the biological value (BV) and net protein utilisation, (NPU), of Bengal gram dhokla improved significantly (P<0.05). The TD of fermented jowar increased significantly (P < 0.05) but not that of ragi, bajra and the legume products. BV and NPU of both jowar and ragi products increased significantly on fermentation (P<0.05) but not that of bajra. The thiamin and riboflavin contents of both the legume and millet products increased with increase in fermentation time. Steaming and cooking after fermentation reduced the thiamin and riboflavin content. However, fermentation after cooking of millet batters increased the levels of both vitamins markedly.     

Dental erosion potential of beverages and bottled drinking water in Bangladesh

Dental erosion is a growing health problem linked to the exceptional increase in the consumption of soft drinks, fruit juices, and sport drinks in many countries including Bangladesh. Dental erosion is the chemical dissolution of the dental hard tissues by acids without the involvement of microorganisms. Hydrogen ions (H⁺) from acidic solutions can replace the calcium ions (Ca²⁺) of the enamel, consequently breaking the crystal structure of the enamel and initiating dental erosion. Erosive tooth wear can lead to severe impairment of esthetics along with loss of hardness and functionality. Sources of the erosive acidic challenges can be intrinsic (i.e., gastroesophaegal reflux disease) and/or extrinsic (i.e., exposure from acidic foods and beverages). Continuous intake of drinks or food with pH lower than the critical erosive pH of enamel (5.2–5.5) and root dentin (~6.7) are considered to be responsible for dental erosion. Drinks with low pH and high titratable acidity (TA) have more potential to dissolved enamel and root dentin; on the other hand, drinks with low degree of saturation can stimulate leaching of minerals. In Bangladesh, there is limited scientific information available to assess the potential of dental erosion of the commercially available beverages and drinking water. This research aims to characterize the dental erosion potential of soft drinks, energy drinks, fruit juices, and bottled drinking water available in Bangladesh by determining their pH, TA, calcium (Ca²⁺), and phosphate (PO₄^3?). The degrees of saturation of the selected samples were calculated from the experimental results of pH, calcium, and phosphate levels. Soft drinks were found to have high erosion potential followed by energy drinks, fruit juices, and bottled drinking water. Most of the beverages locally available were found highly acidic. Phosphate levels were high in black cola drinks. Total TA was highest for the energy drinks, and moderate for soft drinks and fruit juices. Fruit juices contained high level of calcium compared with other beverages. The degree of saturation was moderate for fruit juices, and very low for few of the soft drinks and most of the bottled drinking waters. This study will be useful as a reference line for the health professionals and regulatory authorities for quality control of the beverages and bottled drinking water available in the local market.     

Universal mitochondrial 16s rRNA biomarker for mini-barcode to identify fish species in Malaysian fish products

Mislabelling in fish products is a highly significant emerging issue in world fish trade in terms of health and economic concerns. DNA barcoding is an efficient sequencing-based tool for detecting fish species substitution but due to DNA degradation, it is in many cases difficult to amplify PCR products of the full-length barcode marker (~650 bp), especially in severely processed products. In the present study, a pair of universal primers targeting a 198 bp sequence of the mitochondrial 16s rRNA gene was designed for identification of fish species in the processed fish products commonly consumed in Malaysia. The specificity of the universal primers was tested by both in-silico studies using bioinformatics software and through cross-reaction assessment by practical PCR experiments against the DNA from 38 fish species and 22 other non-target species (animals and plants) and found to be specific for all the tested fish species. To eliminate the possibility of any false-negative detection, eukaryotic endogenous control was used during specificity evaluation. The developed primer set was validated with various heat-treated (boiled, autoclaved and microwaved) fish samples and was found to show high stability under all processing conditions. The newly developed marker successfully identified 92% of the tested commercial fish products with 96–100% sequence similarities. This study reveals a considerable degree of species mislabelling (20.8%); 5 out of 24 fish products were found to be mislabelled. The new marker developed in this work is a reliable tool to identify fish species even in highly processed products and might be useful in detecting fish species substitution thus protecting consumers’ health and economic interests.     

Enhancement of Chilling Stress Tolerance of Tomato Fruit by Postharvest Brassinolide Treatment

Tomatoes, originally a tropical fruit, cannot easily be stored at low temperatures, due to the risk of chilling injury (CI). To develop an effective technique to reduce CI, the effects of treatment with 0, 3, and 6 μM brassinolide (BR) on chilling injury, electrolyte leakage (EL), contents of malondialdehyde (MDA) and proline, and activities of phospholipase D (PLD) and lipoxygenase (LOX) were investigated in tomato fruit stored at 1 °C for 21 days. Treatment with BR, especially at 6 μM, significantly alleviated chilling injury, reduced EL and MDA content, and increased proline content. Also, fruit treated with BR exhibited significantly lower PLD and LOX activities as compared with the control fruit. These results suggest that PLD and LOX are associated with the induction of CI in tomato fruit. BR might reduce CI by inhibiting PLD and LOX activities and by enhancing membrane integrity.     

Quantitative duplex real-time polymerase chain reaction assay with TaqMan probe detects and quantifies Crocodylus porosus in food chain and traditional medicines

Consumption and exploitation of crocodiles have been rampant for their exotic, nutritive and medicinal attributes. These depredations are alarming and although they have continued to be monitored by wildlife and conservation agencies, unlawful trading of crocodiles shows an increasing trend worldwide. Recently, conventional polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) assays for crocodile have been documented but they are only suitable for identification and cannot quantify adulterations. We described here a quantitative duplex real-time PCR assay with probes to quantify contributions from Crocodylus porosus materials simultaneously. A very short amplicon size of 127bp was used because longer targets could have been broken down in samples, bringing considerable uncertainty in molecular analysis. We have validated a TaqMan probe-based duplex real-time PCR (qPCR) assay for the detection of 0.004 ng DNA in pure state and 0.1% target meat in model chicken meatball. False negative detection was eliminated through an endogenous control (141-bp site of eukaryotic 18S rRNA). Analysis of 12 model chicken meatballs adulterated with C. porosus reflected 96.3?120.2% target recovery at 0.1?10% adulterations. A validation test of 21 commercial food and traditional medicine (TM) crocodile-based products showed 100% effectiveness. Short amplicon sizes, alternative complementary target, exceptional stability and superior sensitivity suggested the assay could be used for the identification and quantitative determination of C. porosus in any food or TM samples even under degraded conditions.     

Response to Heethoff,Norton, and Raspotnig: Ant and Mite Diversity Drives Toxin Variation in the Little Devil Poison Frog and Erratum

Our recent publication titled “Ant and Mite Diversity Drives Toxin Variation in the Little Devil Poison Frog” aimed to describe how variation in diet contributes to population differences in toxin profiles of poison frogs. Some poison frogs (Family Dendrobatidae) sequester alkaloid toxins from their arthropod diet, which is composed mainly of ants and mites. Our publication demonstrated that arthropods from the stomach contents of three different frog populations were diverse in both chemistry and species composition. To make progress towards understanding this trophic relationship, our main goal was to identify alkaloids that are found in either ants or mites. With the remaining samples that were not used for chemical analysis, we attempted to identify the arthropods using DNA barcoding of cytochrome oxidase 1 (CO1). The critique of Heethoff, Norton, and Raspotnig refers to the genetic analysis of a small number of mites. Here, we respond to the general argument of the critique as well as other minor issues detailed by Heethoff, Norton, and Raspotnig.     

Coal combustion residues from pulp and paper mills for potential applications

Coal combustion power stations generate huge quantities of ash annually; thus, utilization of such waste residues is an important and essential component for sustainable disposal and management. This paper summarizes an investigation carried out on the coal combustion residues (CCRs) collected from Cachar Paper Mill, Assam, India. A thorough characterization of ash has been carried out with respect to its physicochemical, mineralogical, and morphological features by using density determination, loss on ignition (LOI) determination, Fourier transform infrared, X-ray diffraction, X-ray fluorescence, scanning electron microscopy with electron dispersive X-ray, etc. . The coarser fraction appears to contain a high percentage of char, semi-coked/coked carbonaceous particles, and exceptionally high LOI (86%) values. The carbonaceous matters contain some aliphatic carbon, which implies incomplete combustion. For correlating the total characteristic features, various experiments were performed based on which a number of possible potential utilization directions were suggested. Furthermore, the coarser particles showed excellent water-holding capacities (WHCs, 400%) and good adsorption capabilities, due to the presence of micro- and macropores.     

Analysis and price prediction of cryptocurrencies for historical and live data using ensemble-based neural networks

Knowledge and Information Systems - The popularity of cryptocurrencies has been on the rise with the emergence of blockchain technologies. There have been enormous investments in the cryptocurrency...     

Miniaturized Novel UWB Band-Notch Textile Antenna for Body Area Networks

This paper presents the design and analysis of a miniaturized and novel wearable ultra-wideband (UWB) band-notch textile antenna for Body Area Networks (BANs). The major goal of building the antenna for wearable applications with band notch in X-band is to reject the downlink band (7.25 to 7.75 GHz) of satellite communication in the UWB frequency ranges of 3.1–10.6 GHz to keep away from interference. Computer Simulation Technology (CST) TM Microwave Studio, which is user-friendly and reliable, was used to model and simulate the antenna. The radiating element of the antenna is designed on Jeans’ textile substrate, which has a relative permittivity of 1.7. The thickness of the jeans’ fabric substrate has been considered to be 1 mm. Return loss, gain, bandwidth, impedance, radiation, and total efficiency, and radiation patterns are presented and investigated. The antenna is simulated placed on the three layers of the human body model, and the on-body results are summarized in comparison with free space. Results and analysis indicate that this antenna has good band-notch characteristics in the frequency range of 7.25 GHz to 7.75 GHz. The parametric study varying the relative permittivity of Jeans’ fabric substrate of this antenna is also evaluated. In addition, effects on the antenna parameters of variation of ground plane size have been reported. The antenna is 25 mm × 16 mm × 1.07 mm in total volume. Results reveal that this antenna achieves the design goal and performs well both in free space and on the body.