Preparation and in vitro antiproliferative effect of tocotrienol loaded lipid nanoparticles

The primary objective of this study was to prepare nanostructured lipid carriers loaded with tocotrienol-rich-fraction of palm oil (TRF-NLCs) and to evaluate their antiproliferative effects against neoplastic +SA mammary epithelial cells. This necessitated optimizing the ultrasonic homogenization process parameters and the surfactant to lipid ratio within the NLCs. Therefore, sonication time and pulsar rate were initially evaluated for their effect on the size and polydispersity of the nanoparticles using a full factorial design. Also, varying the surfactant to lipid ratio from 0.25:1 to 3:1 was evaluated for its effect on the same responses. Optimal nanoparticles were obtained when dispersions containing a surfactant to lipid ratio of 0.5:1, with a total lipid concentration of 0.25 (w/v), were sonicated at 60% pulsar rate for 10 min. These parameters were subsequently used to prepare TRF-NLCs. TRF was loaded into the nanoparticles by substituting 10% (TRF-10-NLC) or 50% (TRF-50-NLC) of the lipid phase with TRF. In an extended stability study, no significant change in particle size of the TRF-NLCs was observed over 6 months of storage. In the cell culture studies, TRF-NLCs were shown to exhibit potent antiproliferative effect against neoplastic +SA mammary epithelial cells. The IC₅₀ values of TRF-10-NLCs were 2-fold lower than the IC₅₀ value of the reference TRF/BSA solution. In contrast, TRF-50-NLCs had comparable IC₅₀ values as the TRF/BSA solution, which signified the importance of TRF encapsulation within NLCs on their activity. Furthermore, these findings suggested that TRF-NLCs may have potential value in the treatment of breast cancer.     

Computing well diagrams for vector fields on Rn

Using topological degree theory, we present a fast algorithm for computing the well diagram, a quantitative property, of a vector field on Euclidean space.     

A loop-by-loop defect rectification procedure for optimal synthesis of Stephenson III path generators

This paper presents a formulation of constraints for the synthesis of Stephenson III mechanism and a loop-by-loop defect-rectification procedure. The procedure divides the Stephenson III mechanism into two loops, namely, Loop I, i.e., four-bar, and Loop II, i.e., five-bar mechanisms. Then, the defects are identified using the established methodology to formulate the defect-specific constraints in the simplified form. Based on the constraints, an optimization problem is formulated to synthesize a Stephenson III mechanism for path generation. A well-established meta-heuristic algorithm is used to solve the constrained optimization problem. For demonstrating the effectiveness of the formulated constraints, two numerical examples are considered, in which Stephenson III path generator mechanisms are synthesized. It is found that the mechanisms synthesized using the proposed procedure are defect-free when constraints are imposed, which is verified using the stick-diagram.

     

Magnetic field effect on an exciplex between N-vinyl carbazole grafted on cellulose acetate film and 1,4-dicyanobenzene

The present work emphasises the investigation of photoinduced electron transfer reaction between an electron-donor fluorophore, N-vinyl carbazole (VCZ), grafted on a polymeric cellulose acetate film and an electron-acceptor, 1,4-dicyanobenzene, in the presence of an external magnetic field that serves as a powerful tool to identify the spin states where the initial electron transfer occurs and to modulate the course of the reaction as desire. Here initial electron transfer occurs in the singlet spin state, and the formation of exciplex increases in the presence of magnetic field. The maximum field effect is obtained in the solvent with medium dielectric constant (ε_max) around 8.0. The ε_max value indicates that the extent of charge transfer in this exciplex is less compared to other similar systems studied so far, owing to the characteristic binding of VCZ to the polymeric backbone through oxygen atom. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3910–3915, 1999     

Stiff chain persistence lengths in liquid crystalline copolyesters

This paper describes a continuation of our X-ray diffraction work on the structure of the mesomorphic copolyesters prepared from p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA). The X-ray patterns of meltspun fibers of these copolymers show a series of aperiodic meridional maxima, and these are predicted by a model consisting of stiff extended chains of completely random copolymer sequence. The calculated intensity data are independent of the chain length for the model, except that the width of the peak at d≃2.1Å decreases with increasing chain length. For 58/42 copoly(HBA/HNA) the best agreement obtained is for a chain length of 11 monomers, and this corresponds to a correlation or persistence length for the stiff chain conformation in the solid state. This effect has been modeled for an infinite chain by deriving experimental monomer length distribution functions, from a survey of the conformations of models of typical random chain sequences. The distribution function is then incorporated into the intensity calculations and leads to prediction of peak widths that are comparable to those observed.     

Site Density Functional Theory and Structural Bioinformatics Analysis of the SARS-CoV Spike Protein and hACE2 Complex

The entry of the SARS-CoV-2, a causative agent of COVID-19, into human host cells is mediated by the SARS-CoV-2 spike (S) glycoprotein, which critically depends on the formation of complexes involving the spike protein receptor-binding domain (RBD) and the human cellular membrane receptor angiotensin-converting enzyme 2 (hACE2). Using classical site density functional theory (SDFT) and structural bioinformatics methods, we investigate binding and conformational properties of these complexes and study the overlooked role of water-mediated interactions. Analysis of the three-dimensional reference interaction site model (3DRISM) of SDFT indicates that water mediated interactions in the form of additional water bridges strongly increases the binding between SARS-CoV-2 spike protein and hACE2 compared to SARS-CoV-1-hACE2 complex. By analyzing structures of SARS-CoV-2 and SARS-CoV-1, we find that the homotrimer SARS-CoV-2 S receptor-binding domain (RBD) has expanded in size, indicating large conformational change relative to SARS-CoV-1 S protein. Protomer with the up-conformational form of RBD, which binds with hACE2, exhibits stronger intermolecular interactions at the RBD-ACE2 interface, with differential distributions and the inclusion of specific H-bonds in the CoV-2 complex. Further interface analysis has shown that interfacial water promotes and stabilizes the formation of CoV-2/hACE2 complex. This interaction causes a significant structural rigidification of the spike protein, favoring proteolytic processing of the S protein for the fusion of the viral and cellular membrane. Moreover, conformational dynamics simulations of RBD motions in SARS-CoV-2 and SARS-CoV-1 point to the role in modification of the RBD dynamics and their impact on infectivity.     

Higher-Order Nonclassicality in Photon Added and Subtracted Qudit States

Higher-order nonclassical properties of r photon added and t photon subtracted qudit states (referred to as rPAQS and tPSQS, respectively) are investigated here to answer: How addition and subtraction of photon can be used to engineer higher-order nonclassical properties of qudit states? To obtain the answer, higher-order moment of relevant bosonic field operators is first obtained and subsequently used to study the higher-order nonclassical properties (e.g., higher-order antibunching, higher-order squeezing, and higher-order sub-Poissonian photon statistics) of the corresponding states. These witnesses establish that rPAQS and tPSQS are highly nonclassical. To quantitatively establish this observation and to make a comparison between rPAQS and tPSQS, volumes of the negative part of Wigner function are computed. Finally, for the sake of verifiability of the obtained results, optical tomograms are also reported. Throughout the study, a particular type of qudit state named as a new generalized binomial state is used as an example.