Production of Biodegradable Polymer from Agro-Wastes in Alcaligenes sp. and Pseudomonas sp.

The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.     

Graphene quantum dot–based electrochemical biosensing for early cancer detection

Electrochemical biosensing systems coupled with graphene quantum dots (GQDs) have demonstrated suitability for cancer diagnostic strategies, particularly to identify the changes facilitating the early phases of tumorigenesis as well as to detect ultralow concentrations of biomarkers that distinguish between normal and malignant cells. GQDs, known as a novel class of zero-dimensional semiconductor nanocrystals, are tiny graphene particles arranged in a honeycomb structure with a size range of 1–50 nm. The size of these GQDs is comparable with the size of biomolecules, thereby providing an ideal platform to study biomolecules such as proteins, cells, and viruses. GQDs are a superior platform for specific and sensitive recognition of cancer biomarkers; they are highly synergistic with electrochemical sensors. This review will shed light on the recent advancements made in the field of GQD-based electrochemical sensors for early cancer detection, with the aim of highlighting the prospects for further development in cancer diagnostics.     

Decoherence, time scales and pointer states

Certain issues regarding the time-scales over which environment-induced decoherence occurs, and the nature of emergent pointer states, are discussed. A model system, namely a Stern-Gerlach setup coupled to a quantum mechanical “heat-bath” is studied. The emergent pointer states for this system are obtained, which are different from those discussed in the literature. It is pointed out that this difference is due to some confusion regarding the decoherence time-scale, which is clarified here.     

Cosmology with rolling tachyon

We examine the possibility of rolling tachyon to play the dual role 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. On leave from Jamia Millia Islamia, New Delhi 110 025, India     

A stochastic model for transient magnetic fields as observed by perturbed angular distribution of gamma rays

A stochastic model is introduced to study the transient magnetic field (TF) experienced by the nuclei of fast ions traversing a ferromagnetic medium. The field is assumed to arise primarily from the bound electrons of the ion, polarized by the internal magnetic field of the ferromagnetic specimen. Spin-flip scattering is considered to be the dominant mechanism for polarization transfer from the host to the ion. Electron capture and loss mechanisms are also taken into account in a phenomenological manner. An analytical expression is derived for the TF which depends on the electron capture and loss cross-sections. The result for the perturbation factor is shown to be more general than that derived by Abragam and Pound and reduces to their result in the appropriate limit.     

Dye adsorbed few-layer thick Ti3C2Tx-MXenes for direct electrochemical detection of CD44 proteins

The direct electrochemical detection of cancer biomarkers using single single-component platforms is challenging. Herein, we propose constructing an efficient screen-printed electrode (SPE) based platform for selective detection of CD44 proteins, a non-kinase transmembrane glycoprotein. A sensing platform, MB-MX/HA/SPE, was developed by incorporating few-layered Ti₃C₂T_x nanosheets pre-loaded with methylene blue (MB) dye. The nanosheets were subsequently immobilized with hyaluronic acid (HA), which served as a ligand for the specific recognition of CD44. The simple electrode configuration and the highly conductive Ti₃C₂T_x facilitated the electrochemical oxidation of MB, generating a reference SWV signal that declined proportionally with the increasing concentration of CD44 owing to ligand (HA)-protein interaction. The sensor could register a sensitive inhibition response in the concentration range of 0.1 to 7.25 ng.mL⁻¹ with a detection limit of 1.2×10⁻² ng.mL⁻¹ for CD44 proteins. Moreover, the synergistic combination of the highly conductive/adsorptive Ti₃C₂T_x nanosheets and hyaluronic acid (HA) led to strong antifouling characteristics even in the presence of other common proteins, such as bovine serum albumin (BSA), haemoglobin (Ig), immunoglobulin G (IgG), prostate-specific antigen (PSA), and neuron-specific enolase (NSE). The proposed strategy eliminates the need for additional components in the electrode modification procedure. In addition, incorporating MXenes as electrode material paves the way for developing sensitive biosensors with prospective applications in cancer diagnosis.     

Quantum eraser for three-slit interference

It is well known that in a two-slit interference experiment, if the information, on which of the two paths the particle followed, is stored in a quantum path detector, the interference is destroyed. However, in a set-up where this path information is ‘erased’, the interference can reappear. Such a set-up is known as a quantum eraser. A generalization of quantum eraser to a ‘three-slit’ interference is theoretically analysed. It is shown that three complementary interference patterns can arise out of the quantum erasing process.     

Exploration of superhalogen nature of Pt(CN)n complexes (n = 1–6) and their abilities to form supersalts and superacids: a DFT–D3 study

Structural Chemistry - Unique superhalogen properties of Pt(CN)n complexes (n = 1–6) have been investigated under the quantum chemical formalism. The study involves theoretical calculations...