Oblique Long Wave Scattering by an Array of Bottom-Standing Non-Smooth Breakwaters

Bragg scattering of surface gravity waves by an array of submerged bottom-standing non-smooth breakwaters is studied under the assumption of linearized long wave theory. The closed-form long-wave analytical solutions are derived and validated by comparing them with the results available in the literature. The role of various physical parameters such as breakwaters friction coefficient, depth, width and gap between the adjacent breakwaters are investigated by analyzing the reflection and transmission coefficients. Further, the time-domain simulation for the scattering of long gravity waves over multiple breakwaters is analysed for different values of parameters of breakwaters. The results reveal that the rough surface of the breakwater plays a vital role in reducing wave reflection and transmission. Moreover, it is observed that the transmitted wave dissipates completely for larger values of friction parameters. For certain critical angles, change in wave dissipation becomes maximum due to the variation of phase of the incident wave. Various findings can be considered as benchmark results for the design of the non-smooth structures to attenuate the waves based on the Bragg reflection

Temperature-dependent loop formation kinetics in flexible peptides studied by time-resolved fluorescence spectroscopy

Looping rates in short polypeptides can be determined by intramolecular fluorescence quenching of a 2,3-diazabicyclo[2.2.2]oct-2-ene-labeled asparagine (Dbo) by tryptophan. By this methodology, the looping rates in glycine-serine peptides with the structure Trp-(Gly-Ser)n-Dbo-NH2 of different lengths (n = 0–10) were determined in dependence on temperature in D2O and the activation parameters were derived. In general, the looping rate increases with decreasing peptide length, but the shortest peptide (n=0) shows exceptional behavior because its looping rate is slower than that for the next longer ones (n=1,2). The activation energies increase from 17.5 kJ mol−1 for the longest peptide (n=10) to 20.5 kJ mol−1 for the shortest one (n=0), while the pre-exponential factors (log⁡(A/s−1)) range from 10.20 to 11.38. The data are interpreted in terms of an interplay between internal friction (stiffness of the biopolymer backbone and steric hindrance effects) and solvent friction (viscosity-limited diffusion). For the longest peptides, the activation energies resemble more and more the value expected for solvent viscous flow. Internal friction is most important for the shortest peptides, causing a negative curvature and a smaller than ideal slope (ca. –1.1) of the double-logarithmic plots of the looping rates versus the number of peptide chain segments (N). Interestingly, the corresponding plot for the pre-exponential factors (logA versus logN) shows the ideal slope (–1.5). While the looping rates can be used to assess the flexibility of peptides in a global way, it is suggested that the activation energies provide a measure of the “thermodynamic” flexibility of a peptide, while the pre-exponential factors reflect the “dynamic” flexibility

An investigation of heavy metal adsorption by hexa-dentate ligand-modified magnetic nanocomposites

<p>Advancement of an efficient and cost-effective method for heavy metal removal from contaminated water utilising Fe₃O₄–APTES–EDTA (FAE) nanocomposite, a productive reusable adsorbent, is explained in this study. The novel FAE nanocomposite was prepared and characterised using different techniques such as FTIR, XRD, TEM, EDS, BET, TGA, EDX and Zeta potential techniques. FAE is found to be a good adsorbent for Pb²⁺, Cd²⁺, Ni²⁺, Co²⁺ and Cu²⁺ removal with a higher adsorption capacity. The maximum adsorption capacity of Pb²⁺, Cd²⁺, Ni²⁺, Co²⁺ and Cu²⁺ are found to be 11.31, 13.88, 7.64, 4.86 and 78.67 mg/g, respectively. The adsorption and desorption cycle was studied for five cycles with minimal loss of efficiency.</p

A Spectroscopic and Molecular Simulation Approach toward the Binding Affinity between Lysozyme and Phenazinium Dyes: An Effect on Protein Conformation

A comparative study of binding interaction between Safranin O (SO) and Neutral Red (NR) with lysozyme (Lyz) has been reported using several spectroscopic methods along with computational approaches. Steady-state fluorescence measurements revealed static quenching as the major quenching mechanism in Lyz–SO and Lyz–NR interaction, which is further supported by time-resolved fluorescence and UV–vis measurements. Additionally, binding and thermodynamic parameters of these interactions are calculated from temperature dependent fluorescence data. Moreover, conformational changes of protein upon binding with SO and NR are provided by synchronous and circular dichroism (CD) measurements. Molecular docking study provided the exact binding location of SO and NR in lysozyme. Along with this study, molecular dynamics simulation is carried out to measure the stability of Lyz, Lyz–SO, and Lyz–NR complex. The present study revealed the strong binding affinity of dyes with lysozyme, and this study would be helpful toward medical and environmental science