Synthesis and characterization of multiwalled carbon nanotubes‐polymethyl methacrylate composites prepared by in situ polymerization method

Multiwalled carbon nanotubes‐polymethyl methacrylate composites (MWCNT‐PMMA) were prepared by an in situ polymerization method. The effect of nanotube content and their surface functionalization on the mechanical properties of the resulting nanocomposites was investigated. The use of only 1.8 wt% functionalized tubes improved flexural modulus by about 43% and flexural strength by about 60%. In situ polymerization using functionalized tubes improved interfacial bonding strength due to a chemical interaction between carbon nanotubes and the growing PMMA, which resulted in improved load transfer mechanism. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Lyophilization of unit dose pharmaceutical dosage forms

A lyophilization process for a pharmaceutical unit dosage form was developed which comprised a container closed with an impermeable membrane pierced with one or more holes through which the material in the container can be lyophilized. The hole or holes in the membrane have to be sufficiently large to allow water vapor to escape but small to ensure that the material is kept within the container. Lyophilization from sealed, perforated, unit-dose package has shown to be feasible. The technique offers a novel convenient means of lyophilizing nonsterile products in their primary pack and increases the potential for the development of lyophilized formulations for nonparenteral applications.     

Adapted Long Short-Term Memory (LSTM) for Concurrent\\ Human Activity Recognition

In this era, deep learning methods offer a broad spectrum of efficient and original algorithms to recognize or predict an output when given a sequence of inputs. In current trends, deep learning methods using recent long short-term memory (LSTM) algorithms try to provide superior performance, but they still have limited effectiveness when detecting sequences of complex human activity. In this work, we adapted the LSTM algorithm into a synchronous algorithm (sync-LSTM), enabling the model to take multiple parallel input sequences to produce multiple parallel synchronized output sequences. The proposed method is implemented for simultaneous human activity recognition (HAR) using heterogeneous sensor data in a smart home. HAR assists artificial intelligence in providing services to users according to their preferences. The sync-LSTM algorithm improves learning performance and sees its potential for real-world applications in complex HAR, such as concurrent activity, with higher accuracy and satisfactory computational complexity. The adapted algorithm for HAR is also applicable in the fields of ambient assistive living, healthcare, robotics, pervasive computing, and astronomy. Extensive experimental evaluation with publicly available datasets demonstrates the competitive recognition capabilities of our approach. The sync-LSTM algorithm improves learning performance and has the potential for real-life applications in complex HAR. For concurrent activity recognition, our proposed method shows an accuracy of more than 97%.     

Low temperature synthesis of magnetite and maghemite nanoparticles

We report on the synthesis of iron oxide nanoparticles below 100 degrees C by a simple chemical protocol. The uniqueness of the method lies in the use of Ferrous ammonium sulphate (in conjugation with FeCl3) which helps maintain the stability of Fe2+ state in the reaction sequence thereby controlling the phase formation. Hexamine was added as the stabilizer. The nanoparticles synthesized at three different temperatures viz, 5 degrees, 27 degrees, and 95 degrees C are characterized by several techniques. Generally, when a mixture of Fe3+ and Fe2+ is added to sodium hydroxide, alpha-Fe2O3 (the anti-ferromagnetic phase) is formed after the dehydration process of the hydroxide. In our case however, the phases formed at all the three temperatures were found to be ferro (ferri) magnetic, implying modification of the formation chemistry due to the specifics of our method. The nanoparticles synthesized at the lowest temperature exhibit magnetite phase, while increase in growth temperature to 95 degrees C leads to the maghemite phase.     

Synthesis and characterization of poly(butylene oxide) grafted carbon nanofibers

The grafting of polybutylene oxide onto purified and functionalized carbon nanofibers is reported. Grafting was possible after the insertion of 2-(formyloxy)ethyl 2-bromo-2-methylpropanoate onto the carbon nanofibers. The polymerization of tetrahydrofuran was mediated by copper(I) bromide and 1,1,4,7-pentamethyl diethylenetriamine. The polymer-grafted carbon nanofibers were characterized by Raman spectrsocopy, Transmission Electron Microscopy, and Thermogravimetric Analysis. TEM images of CNF-COOH (A), CNF-PBO (B), completely open tip of CNF-COOH, and coated tip of CNF-PBO (D) are shown in the left panel. The right panel depicts the distribution of bromine (blue), and carbon (red) atoms inside and in the vicinity of CNF-Br (as obtained by Electron Energy Loss Spectroscopy). The bottom shows the actual doped CNF. Preliminary data showed that these modified fibers have potential applications as smart (electrorheological) fluids.     

A case study: Te in ZnSe and Mn-doped ZnSe quantum dots

Photoluminescence (PL) behavior of ZnSe(1-y)Te(y) quantum dots is investigated by varying Te concentration as well as size. The striking effect of quantum confinement is the observation of isoelectronic center-related emission at room temperature in lieu of near-band-edge emission that dominates the optical scenario. ZnSe(0.99)Te(0.01) quantum dots were also doped by Mn(2+) ions. The Mn(2+) ion-related d-d transition is drastically suppressed by Te isoelectronic centers. Incorporation of Mn(2+) at substitutional sites in ZnSe(0.99)Te(0.01) quantum dots is also confirmed by the electron paramagnetic resonance measurements. Effect of Te isoelectronic impurity on the emission behavior is more pronounced than that of Mn(2+) ions. A subtle blueshift in the orange d-d transition is a sign of a decrease in crystal field strength. PL and photoluminescence excitation measurements on Zn(1-x)Se(0.99)Te(0.01)Mn(x) quantum dots indicate that the transition probability from the lowest unoccupied molecular orbital to Te levels is substantially larger than that to Mn(2+) d-d levels.     

Role of the Pangolin in Origin of SARS-CoV-2: An Evolutionary Perspective

After the recent emergence of SARS-CoV-2 infection, unanswered questions remain related to its evolutionary history, path of transmission or divergence and role of recombination. There is emerging evidence on amino acid substitutions occurring in key residues of the receptor-binding domain of the spike glycoprotein in coronavirus isolates from bat and pangolins. In this article, we summarize our current knowledge on the origin of SARS-CoV-2. We also analyze the host ACE2-interacting residues of the receptor-binding domain of spike glycoprotein in SARS-CoV-2 isolates from bats, and compare it to pangolin SARS-CoV-2 isolates collected from Guangdong province (GD Pangolin-CoV) and Guangxi autonomous regions (GX Pangolin-CoV) of South China. Based on our comparative analysis, we support the view that the Guangdong Pangolins are the intermediate hosts that adapted the SARS-CoV-2 and represented a significant evolutionary link in the path of transmission of SARS-CoV-2 virus. We also discuss the role of intermediate hosts in the origin of Omicron.     

Omnidirectional Reflectance of Superconductor-Dielectric Photonic Crystal in THz Frequency Range

Journal of Superconductivity and Novel Magnetism - In this paper, we analyze the omnidirectional reflection characteristics of a superconductor photonic crystal for TE and TM modes, by using the...     

Analysis of dipyridine dipyrrole based molecules for solar cell application using computational approach

Journal of Computational Electronics - In this work, six dipyridine dipyrrole (DPDP) derivatives are reported as π-conjugated, electron donor molecules used in BHJ solar cells. Density...