Synthesis of magnetic core–shell Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>–Au nanoparticle for biomolecule immobilization and detection

The production of monodispersed magnetic nanoparticles with appropriate surface modification has attracted increasing attention in biomedical applications including drug delivery, separation, and purification of biomolecules from the matrices. In the present study, we report rapid and room temperature reaction synthesis of gold-coated iron nanoparticles in aqueous solution using the borohydride reduction of HAuCl₄ under sonication for the first time. The resulting nanoparticles were characterized with transmission electron microscopy (TEM), electron spectroscopy for chemical analysis (ESCA), ultraviolet visible spectroscopy (UV–Vis), and X-ray diffraction (XRD). Surface charges and magnetic properties of the nanoparticles were also examined. The pattern of Fe₃O₄ nanoparticles is face centered cubic with an average diameter of 9.5 nm and the initial reduction of gold on the surface of Fe₃O₄ particles exhibits uniform Fe₃O₄–Au nanoparticles with an average diameter of 12.5 nm. The saturation magnetization values for the uncoated and gold-coated Fe₃O₄ nanoparticles were found to be 30 and 4.5 emu/g, respectively, at 300 K. The progression of binding events between boronic acid terminated ligand shell and fructose based on the covalent bonding interaction was measured by absorbance spectral changes. Immunomagnetic separation was also performed at different E. coli concentration to evaluate capturing efficiency of resulting nanoparticles. Immunomagnetic separation percentages were varied in a range of 52.1 and 21.9% depend on the initial bacteria counts.     

An introduced effective-field theory study of spin-1 transverse Ising model with crystal field anisotropy in a longitudinal magnetic field

A spin-1 transverse Ising model with longitudinal crystal field in a longitudinal magnetic field is examined by introducing an effective field approximation (IEFT) which includes the correlations between different spins that emerge when expanding the identities. The effects of the crystal field as well as the transverse and longitudinal magnetic fields on the thermal and magnetic properties of the spin system are discussed in detail. The order parameters, Helmholtz free energy, entropy and specific heat curves are calculated numerically as functions of the temperature and Hamiltonian parameters. A number of interesting phenomena such as reentrant phenomena originating from the temperature, crystal field, transverse and longitudinal magnetic fields have been found.     

Optical Solitons and Stability Analysis in Ring-Cavity Fiber System with Carbon Nanotube as Saturable Absorber

This paper addresses the ring-cavity fiber laser system. A class of gray and black soliton solutions of the model are reported by adopting an appropriate envelope ansatz. Further more, the modulation instability (MI) of the equation is studied using the linear-stability analysis (LSA) technique and the MI gain spectrum is derived. Some physical interpretations and analysis of the results obtained are also presented.     

Evaluating the Learning Procedure of CNNs through a Sequence of Prognostic Tests Utilising Information Theoretical Measures

Deep learning has proven to be an important element of modern data processing technology, which has found its application in many areas such as multimodal sensor data processing and understanding, data generation and anomaly detection. While the use of deep learning is booming in many real-world tasks, the internal processes of how it draws results is still uncertain. Understanding the data processing pathways within a deep neural network is important for transparency and better resource utilisation. In this paper, a method utilising information theoretic measures is used to reveal the typical learning patterns of convolutional neural networks, which are commonly used for image processing tasks. For this purpose, training samples, true labels and estimated labels are considered to be random variables. The mutual information and conditional entropy between these variables are then studied using information theoretical measures. This paper shows that more convolutional layers in the network improve its learning and unnecessarily higher numbers of convolutional layers do not improve the learning any further. The number of convolutional layers that need to be added to a neural network to gain the desired learning level can be determined with the help of theoretic information quantities including entropy, inequality and mutual information among the inputs to the network. The kernel size of convolutional layers only affects the learning speed of the network. This study also shows that where the dropout layer is applied to has no significant effects on the learning of networks with a lower dropout rate, and it is better placed immediately after the last convolutional layer with higher dropout rates.     

Electron Transfer Reactions of Radical Anions with TEMPO: A Versatile Route for Transformation of Living Anionic Polymerization into Stable Radical‐Mediated Polymerization

Summary: The possibility of transforming a living anionic polymerization into a stable radical‐mediated radical polymerization (SFRP) was demonstrated. For this purpose, 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) alcoholate, formed by a one‐electron redox reaction between potassium naphthalene and TEMPO, was used to initiate the living anionic polymerization of ethylene oxide (EO). Poly(ethylene oxide) obtained in this way possessed TEMPO terminal units and was subsequently used as an initiator for the SFRP of styrene to give block copolymers.

A one‐electron redox reaction gives rise to TEMPO alcoholate, which is able to initiate the living anionic polymerization of ethylene oxide (EO).     

Direct and sensitized photoinitiated cationic polymerization using pyridinium salts

Results of polymerization and laser flash photolysis studies concerning the direct and indirect photoinitiation of cationic polymerizations using N-alkoxy pyridinium and N-alkoxy quinolinium salts are presented. The indirect action can be based on (a) the generation of carbocations via the oxidation of photochemically produced free radicals and (b) the generation of radical cations via the reaction of electronically excited sensitizers with pyridinium or quinolinium ions. With respect to (a) substituted vinyl bromides were found be an effective source of oxidizable free radicals (vinyl radicals), and regarding (b) singlet or triplet excited states of thioxanthone, anthracene, perylene and phenothiazine, which, in the ground state, strongly absorb light in the 300 to 400 nm range, were found to react rapidly with pyridinium salts.     

Hybrid thermotropic liquid-crystalline block copolymers

A new approach to the preparation of two classes of block copolymers containing liquid-crystalline segments is reported. Copolymers 1 and 2 are constituted by polytetrahydrofuran and side-chain liquid-crystalline polymethacrylate blocks, whereas block copolymers 3 consist of polystyrene and main-chain liquid-crystalline polyester blocks. The synthetic procedures leading to copolymers 1-3 are extremely versatile and can be used to prepare a great variety of block copolymer architectures. In both copolymer classes the chemically different blocks are strongly segregated in the solid and melt phases and undergo individual phase transitions. The mesophase transition temperatures of the liquid-crystalline blocks are very similar to those of the corresponding homopolymers, and their enthalpies are directly proportional to the content of the liquid-crystalline block.     

Assessment of Agroeconomic Indicators of Sesamum indicum L. as Influenced by Application of Boron at Different Levels and Plant Growth Stages

To achieve the nutritional target of human food, boron (B) has been described as an essential mineral in determining seed and theoretical oil yield of Sesamum indicum L. The research to increase its cultivation is garnering attention due to its high oil content, quality and its utilization for various purposes, which include human nutrition as well as its use in the food industry. For this, a two-year field experiment was performed at PAU, Punjab, India to determine the effect of different concentrations of foliar-applied B (20, 30 and 40 mg L⁻¹) and different growth stages of crop, i.e., we measured the effects on agroeconomic indicators and certain quality parameters of sesame using different concentrations of B applied at the flowering and capsule formation stages as compared to using water spray and untreated plants. Water spray did not significantly affect the studied parameters. However, B application significantly increased the yield, uptake, antioxidant activity (AOA) and theoretical oil content (TOC) compared to those of untreated plants. The maximum increase in seed yield (26.75%), B seed and stover uptake (64.08% and 69.25%, respectively) as well as highest AOA (69.41%) and benefit to cost ratio (B:C ratio 2.63) was recorded when B was applied at 30 mg L⁻¹ at the flowering and capsule formation stages. However, the maximum sesame yield and B uptake were recorded when B was applied at a rate of 30 mg L⁻¹. A significant increase in TOC was also recorded with a B application rate of 30 mg L⁻¹. For efficiency indices, the higher values of boron agronomic efficiency (BAE) and boron crop recovery efficiency (BCRE) were recorded when B was applied at 20 mg L⁻¹ (5.25 and 30.56, respectively) and 30 mg L⁻¹ (4.96 and 26.11, respectively) at the flowering and capsule formation stages. In conclusion, application of B @ 30 mg L⁻¹ at the flowering and capsule formation stages seemed a viable technique to enhance yield, B uptake and economic returns of sesame.     

Measuring the temperature of the spin via weak measurement

In this study, we give a new proposal to measure the temperature of the spin in a sample in a magnetic resonance force microscopy system by using postselected weak measurement, and investigating the Fisher information to estimate the precision of the scheme. We show that in a high temperature regime the temperature of the spin can be measured via a weak measurement technique with proper postselection and our scheme is able to increase the precision of temperature estimation.     

Photosensitized Cationic Polymerization of Cyclohexene Oxide Using a Phenacylanilinium Salt

The photoinitiated cationic polymerization of cyclohexene oxide with N‐phenacyl‐N,N‐dimethylanilinium hexafluoroantimonate (PDA⁺SbF₆^–) and a polynuclear aromatic compound, such as perylene, anthracene or phenothiazine, or an aromatic carbonyl compound, such as benzophenone or thioxanthone, was studied at λ_inc > 340 nm. All the aromatic sensitizers except benzophenone and thioxanthone are effective in initiating the polymerization at wavelengths where PDA⁺SbF₆^– is transparent. An initiation mechanism is proposed that involves electron transfer from the excited sensitizer to PDA⁺SbF₆^–.