Popper's experiment, Copenhagen Interpretation and Nonlocality

A thought experiment, proposed by Karl Popper, which has been experimentally realized recently, is critically examined. A basic flaw in Popper's argument which has also been prevailing in subsequent debates, is pointed out. It is shown that Popper's experiment can be understood easily within the Copenhagen interpretation of quantum mechanics. An alternate experiment, based on discrete variables, is proposed, which constitutes Popper's test in a clearer way. It refutes the argument of absence of nonlocality in quantum mechanics.Comment: Thoroughly revised. To appear in Int. J. Quantum Informatio

Rapid and label-free detection of COVID-19 using coherent anti-Stokes Raman scattering microscopy

From the 1918 influenza pandemic (H1N1) until the recent 2019 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, no efficient diagnostic tools have been developed for sensitive identification of viral pathogens. Rigorous, early, and accurate detection of viral pathogens is not only linked to preventing transmission but also to timely treatment and monitoring of drug resistance. Reverse transcription-polymerase chain reaction (RT-PCR), the gold standard method for microbiology and virology testing, suffers from both false-negative and false-positive results arising from the detection limit, contamination of samples/templates, exponential DNA amplification, and variation of viral ribonucleic acid sequences within a single individual during the course of the infection. Rapid, sensitive, and label-free detection of SARS-CoV-2 can provide a first line of defense against the current pandemic. A promising technique is non-linear coherent anti-Stokes Raman scattering (CARS) microscopy, which has the ability to capture rich spatiotemporal structural and functional information at a high acquisition speed in a label-free manner from a biological system. Raman scattering is a process in which the distinctive spectral signatures associated with light-sample interaction provide information on the chemical composition of the sample. In this prospective, we briefly discuss the development and future prospects of CARS for real-time multiplexed label-free detection of SARS-CoV-2 pathogens

Graphene-Based Nanocomposites as Antibacterial, Antiviral and Antifungal Agents

Over the past decade, there have been many interesting studies in the scientific literature about the interaction of graphene-based polymeric nanocomposites with microorganisms to tackle antimicrobial resistance. These studies have reported variable intensities of biocompatibility and selectivity for the nanocomposites toward a specific strain, but it is widely believed that graphene nanocomposites have antibacterial, antiviral, and antifungal activities. Such antibacterial activity is due to several mechanisms by which graphene nanocomposites can act on cells including stimulating oxidative stress; disrupting membranes due to sharp edges; greatly changing core structure mechanical strength and coarseness. However, the underlying mechanisms of graphene nanocomposites as antiviral and antifungal agents remain relatively scarce. In this review, recent advances in the synthesis, functional tailoring, and antibacterial, antiviral, and antifungal applications of graphene nanocomposites are summarized. The synthesis of graphene materials and graphene-based polymeric nanocomposites with techniques such as pressurized gyration, electrospinning, chemical vapor deposition, and layer-by-layer self-assembly is first introduced. Then, the antimicrobial mechanisms of graphene membranes are presented and demonstrated typical in vitro and in vivo studies on the use of graphene nanocomposites for antibacterial, antiviral, and antifungal applications. Finally, the review describes the biosafety, current limitations, and potential of antimicrobial graphene-based nanocomposites

Porous Graphene Composite Polymer Fibres

Since the isolation of graphene, there have been boundless pursuits to exploit the many superior properties that this material possesses; nearing the two-decade mark, progress has been made, but more is yet to be done for it to be truly exploited at a commercial scale. Porous graphene (PG) has recently been explored as a promising membrane material for polymer composite fibres. However, controlling the incorporation of high surface area PG into polymer fibres remain largely unexplored. Additionally, most polymer-graphene composites suffer from low production rates and yields. In this paper, graphene-loaded microfibres, which can be produced at a very high rate and yield have been formed with a carrier polymer, polycaprolactone. For the first time, PG has been incorporated into polymer matrices produced by a high-output manufacturing process and analysed via multiple techniques; scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Raman spectra showed that single layer graphene structures were achieved, evidence for which was also backed up by the other techniques. Fibres with an average diameter ranging from 3–8 µm were produced with 3–5 wt% PG. Here, we show how PG can be easily processed into polymeric fibres, allowing for widespread use in electrical and ultrafiltration system

Boron nitride nanoscrolls: structure, synthesis, and applications

This is the author accepted manuscriptBoron nitride nanoscrolls (BNS) are open-ended, one-dimensional (1D) nanostructures made by the process of rolling boron nitride nanosheets (BNNS) into a scroll-like morphology. BNS offer a high surface area to volume ratio and possess many unique properties (similar to carbon nanotubes (CNT), carbon nanoscrolls (CNS) and boron nitride nanotubes (BNT)) such as high resistance to oxidation, chemical stability, increased lubrication, high-temperature resistance, electrical insulation, the ability to cap molecules inside and at the ends,and a wide band gap regardless of chirality. Despite these attractive featuresand properties well suited for applications in biotechnology, energy storage, and electronics, the true potential of boron nitride, and BNS as the next ‘miracle material’ is yet to be fully explored. In this critical review, we assess, for the first time, various studies published on the formation, structural and dynamic characteristics of BNS, potential routes for BNS synthesis, and the toxicology of BNS. Finally, the future perspectives of BNS are discussed in view of its unique and exceptional candidacy for many (real-world) applications

Tracing the Bioavailability of Three-Dimensional Graphene Foam in Biological Tissues

This is the final version of the article. Available from MDPI via the DOI in this record.Graphene-based materials with a three-dimensional (3D) framework have been investigated for a variety of biomedical applications because of their 3D morphology, excellent physiochemical properties, volume stability, and their controllable degradation rate. Current knowledge on the toxicological implications and bioavailability of graphene foam (GF) has major uncertainties surrounding the fate and behavior of GF in exposed environments. Bioavailability, uptake, and partitioning could have potential effects on the behavior of GF in living organisms, which has not yet been investigated. Here, we report a pilot toxicology study on 3D GF in common carps. Our results showed that GF did not show any noticeable toxicity in common carps, and the antioxidant enzymatic activities, biochemical and blood parameters persisted within the standard series. Further histological imaging revealed that GF remained within liver and kidney macrophages for 7 days without showing obvious toxicity. An in vivo study also demonstrated a direct interaction between GF and biological systems, verifying its eco-friendly nature and high biocompatibility.This work was supported by EPSRC Centre for Doctoral Training in Metamaterials, XM2 (Grant No. EP/L015331/1) University of Exeter EX4 4QF, United Kingdom

Cosmological Aspects of Rolling Tachyon

Abstract We examine the possibility of rolling tachyon to play the dual roll of inflaton at early epochs and dark matter at late times. We argue that enough inflation can be generated with the rolling tachyon either by invoking the large number of branes or brane world assisted inflation. However, reheating is problematic in this model

Histopathological changes and antioxidant responses in common carp (Cyprinus carpio) exposed to copper nanoparticles

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordDespite the rapid increase of nanotechnology in a wide array of industrial sectors, the biosafety profile of nanomaterials remains undefined. The accelerated use of nanomaterials has increased the potential discharge of nanomaterials into the environment in different ways. The aquatic environment is mainly susceptible as it is likely to act as an ultimate sink for all contaminants. Therefore, this study assessed the toxicological impacts of waterborne engineered copper nanoparticles (Cu-NPs) on histology, lipid peroxidation (LPO), catalase (CAT), and glutathione (GSH) levels in the gills of common carp (Cyprinus carpio). Nanoparticles were characterized by XRD and SEM techniques. Before starting the sub-acute toxicity testing, 96 h LC50 of Cu-NPs for C. carpio was calculated as 4.44 mg/l. Then based on LC50, C. carpio of 40–45 g in weight were exposed to three sub-lethal doses of waterborne engineered Cu-NPs (0 or 0.5 or 1 or 1.5 mg/l) for a period of 14 days. The waterborne Cu-NPs have appeared to induce alterations in gill histology and oxidative stress parameters in a dose-dependent manner. The gill tissues showed degenerative secondary lamellae, necrotic lamella, fused lamella, necrosis of the primary and secondary lamella, edema, complete degeneration, epithelial lifting, degenerative epithelium, and hyperplasia in a dose-dependent manner. In the gill tissues, waterborne Cu-NPs caused a decreased level of CAT and elevated levels of LPO, and GSH in the fish exposed to the highest dose of 1.5 mg Cu-NPs/l of water. Our results indicate that the exposure to waterborne Cu-NPs was toxic to the aquatic organisms as shown by the oxidative stresses and histological alterations in C. carpio, a freshwater fish of good economic value

Cosmological Aspects of Rolling Tachyon

We examine the possibility of rolling tachyon to play the dual roll of inflaton at early epochs and dark matter at late times. We argue that enough inflation can be generated with the rolling tachyon either by invoking the large number of branes or brane world assisted inflation. However, reheating is problematic in this model.Comment: RevTeX 4 pages, Talk delivered in PASCOS held at TIFR (Mumbai) from 3rd Jan to 9th Jan. To appear in the proceedings of PASCOS to be published in a special issue of Praman

Biocompatibility behavior and biomedical applications of Ti-Ni based shape memory alloys: a brief review

Shape memory alloys provide new areas for the design of biomaterials in biomedical engineering and also for the design of artificial hard tissues and surgical instruments, since they have definite distinctiveness and remarkable characteristics. This study will look at the biocompatibility behavior of Ti-Ni based shape memory alloys and its medical applications with high possible for improving the present and future quality of bioengineering. In particular, the biocompatibility behavior, vivo and vitro corrosion analysis, histological studies of tissues, vitro and vivo cytotoxicity and applications of Ti-Ni based shape memory alloys in the fields of Cardiovascular, Gastroenterology and Urology, Orthopedics and bone-related purposes have been discussed in this paper