Synthetic Characterization of Cellulose from Moringa oleifera seeds and Potential Application in Water Purification

The use of Moringa oleifera seeds for purifying water has been attempted locally in various forms without putting scientific potency of the material into consideration. The cellulose sample isolated from Moringa {oleifera} seed was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The value of the crystallinity index (CIr ) from the XRD pattern is 63.1%. The high degree of crystallinity obtained is attributed to the high percentage of crystallinity index, CIr (i.e. 63.1%). The morphology revealed aggregates of conical and needle-like structure. The FTIR revealed O-H stretching, C-H stretching vibration, and C=O bond stretching functional groups. These characteristics are indicative of the potential of the material in water purification.

Chemical and biological characterization of sulfated chitosan oligomer as heparin mimics

In the present study, chitosan oligomer was modified to sulfated chitosan oligomer (ShCsO) to mimic heparin. Its chemical structure was determined by infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis. The results showed that the FT-IR spectrum band at 799 cm−1 corresponds to C–O–S and that at 1212 cm−1 corresponds to S=O bond stretching, which prove that the sulfate groups are incorporated into chitosan oligomer successfully. The antimicrobial activity of ShCsO against to Bacillus subtilis in 1% concentration was 89.1 ± 1.7% . The IC50 (μg/ml) of ShCsO was 67.75, 56.07, 85.47, and 84.68 for A2780, MCF-7, DU-145, and HepG2, respectively. The results show that this newly synthesized material is a potential candidate to heparin-like chitosan derivatives. According to the literature, it was the first time that chitosan oligomer was modified to mimic heparin.

Synthesis, Characterization And Assessment of Anti Microbial Behaviour of Goat Faecal Mediated Silver Nanoparticles- Fed on Tirumala Hills

To synthesize, characterize, and to assess the anti-microbial activity of silver nanoparticles (AgNPs) induced by goat fecal matter. The AgNPs were processed by the microwave heating method and the characterization was accomplished by employing various spectroscopic approaches such as UV-Visible, FTIR spectroscopy, XRD, Particle size, and Zeta potential analysis. The lmax for both extracts were found at 426& 438nm. The wideband corresponded to O-H stretching vibrations at 3384.0 cm-1, 3273.9 cm-1 and 3366.2 cm-1, bands at 2918.5 cm-1, 2922.5 cm-1, 2853.2 cm-1, and 2850.2 cm-1 corresponded to the N–H and C–H stretching. The bands at 1638.1 cm-1, 1651.9, and 1686.5 cm-1 corresponded to the C=C stretch. Bands of 1460.3 cm-1, 1450.4 cm-1, 1409.2 cm-1 and 1376.3 cm-1 corresponded to C-N, C-C bond stretching vibrations. The stretch of C-O indicates bands at 1159.7 cm-1, 1033.2 cm-1, and 1032.8 cm-1. The synthesized AgNPsdemonstrated good anti-microbial activity on gram +Ve (S.aureus) and gram -Ve (E.coli) bacteria. Bio/Green synthesized AgNPs have shown improved biological performance, this tends to minimize production cost, pollution-free, less chemical usage, and stable generation of nanoparticles.

Synthesis, Characterization And Assessment of Anti Microbial Behaviour of Goat Faecal Mediated Silver Nanoparticles- Fed on Tirumala Hills

To synthesize, characterize, and to assess the anti-microbial activity of silver nanoparticles (AgNPs) induced by goat fecal matter. The AgNPs were processed by the microwave heating method and the characterization was accomplished by employing various spectroscopic approaches such as UV-Visible, FTIR spectroscopy, XRD, Particle size, and Zeta potential analysis. The lmax for both extracts were found at 426& 438nm. The wideband corresponded to O-H stretching vibrations at 3384.0 cm-1, 3273.9 cm-1 and 3366.2 cm-1, bands at 2918.5 cm-1, 2922.5 cm-1, 2853.2 cm-1, and 2850.2 cm-1 corresponded to the N–H and C–H stretching. The bands at 1638.1 cm-1, 1651.9, and 1686.5 cm-1 corresponded to the C=C stretch. Bands of 1460.3 cm-1, 1450.4 cm-1, 1409.2 cm-1 and 1376.3 cm-1 corresponded to C-N, C-C bond stretching vibrations. The stretch of C-O indicates bands at 1159.7 cm-1, 1033.2 cm-1, and 1032.8 cm-1. The synthesized AgNPsdemonstrated good anti-microbial activity on gram +Ve (S.aureus) and gram -Ve (E.coli) bacteria. Bio/Green synthesized AgNPs have shown improved biological performance, this tends to minimize production cost, pollution-free, less chemical usage, and stable generation of nanoparticles.

Charge disproportionation and nano phase separation in $$\textit{R}\mathrm{SrNiO}_{4}$$

We have successfully grown centimeter-sized layered $$\textit{R}\mathrm{SrNiO}_{4}$$ R SrNiO 4 single crystals under high oxygen pressures of 120–150 bar by the floating zone technique. This enabled us to perform neutron scattering experiments where we observe close to quarter-integer magnetic peaks below $$\sim 77~\mathrm{K}$$ ∼ 77 K that are accompanied by steep upwards dispersing spin excitations. Within the high-frequency Ni–O bond stretching phonon dispersion, a softening at the propagation vector for a checkerboard modulation can be observed. We were able to simulate the magnetic excitation spectra using a model that includes two essential ingredients, namely checkerboard charge disproportionation and nano phase separation. The results thus suggest that charge disproportionation is preferred instead of a Jahn–Teller distortion even for this layered $$\mathrm{Ni}^{3+}$$ Ni 3 + system.

Probing the heterogeneous structure of eumelanin using ultrafast vibrational fingerprinting

Eumelanin is a brown-black biological pigment with sunscreen and radical scavenging functions important to numerous organisms. Eumelanin is also a promising redox-active material for energy conversion and storage, but the chemical structures present in this heterogeneous pigment remain unknown, limiting understanding of the properties of its light-responsive subunits. Here, we introduce an ultrafast vibrational fingerprinting approach for probing the structure and interactions of chromophores in heterogeneous materials like eumelanin. Specifically, transient vibrational spectra in the double-bond stretching region are recorded for subsets of electronic chromophores photoselected by an ultrafast excitation pulse tuned through the UV-visible spectrum. All subsets show a common vibrational fingerprint, indicating that the diverse electronic absorbers in eumelanin, regardless of transition energy, contain the same distribution of IR-active functional groups. Aggregation of chromophores diverse in oxidation state is the key structural property underlying the universal, ultrafast deactivation behavior of eumelanin in response to photoexcitation with any wavelength.

“On-The-Fly” Calculation of the Vibrational Sum-Frequency Generation Spectrum at the Air-Water Interface

In the present work, we provide an electronic structure based method for the “on-the-fly” determination of vibrational sum frequency generation (v-SFG) spectra. The predictive power of this scheme is demonstrated at the air-water interface. While the instantaneous fluctuations in dipole moment are obtained using the maximally localized Wannier functions, the fluctuations in polarizability are approximated to be proportional to the second moment of Wannier functions. The spectrum henceforth obtained captures the signatures of hydrogen bond stretching, bending, as well as low-frequency librational modes.

“On-the-fly” calculation of the Vibrational Sum-frequency Generation Spectrum at the Air-water Interface

In the present work, we provide an electronic structure based method for the “on-the-fly” deter- mination of vibrational sum frequency generation (v-SFG) spectra. The predictive power of this scheme is demonstrated at the air-water interface. While the instantaneous fluctuations in dipole moment are obtained using the maximally localized Wannier functions, the fluctuations in polar- izability are approximated to be proportional to the second moment of Wannier functions. The spectrum henceforth obtained captures the signatures of hydrogen bond stretching, bending, as well as low-frequency librational modes.

Mechanisms and measures for the ductility of materials failure

An operational definition for the ductility of failure is given. Many examples illustrate the procedure for specific applications. The ductile/brittle transition is an integral part of the formalism. Further applications are made to the solids forming elements in the Periodic Table. The cases of graphene and diamond are used to verify the procedure. Bond bending and bond stretching are shown to provide an atomic scale criterion for ductile versus brittle failure behaviours.