Enhancement in physicochemical properties of citric acid/nano SiO<Subscript>2</Subscript> treated sustainable wood-starch nanocomposites

Citric acid was used as the cross-linker to prepare the sustainable wood starch nanocomposites (WSNC) from the renewable resources like starch and soft wood flour using water as the solvent. Nano SiO₂ was employed to develop the physicochemical properties of the WSNC via a green path. In this process, starch was grafted with methylmethacrylate (MMA) and SiO₂ was modified with N-cetyl-N,N,N-trimethyl ammonium bromide. Three different percentage of modified nano SiO₂ (1–5 phr) were employed in the preparation of the composites and their properties were characterized by Fourier transform infrared spectroscopy. The morphological features of the composites were investigated through transmission electron microscopy and scanning electron microscopy study. Mechanical and dynamic mechanical properties like storage modulus, loss factors and tan δ value of the composites were thoroughly investigated. Thermal stability, water resistance and flammability of the composites were significantly improved after incorporation of modified SiO₂. The maximum improvements in properties were achieved containing 3 phr modified SiO₂ composites.     

Nondegenerate dual atomic parametric amplifier: entangled atomic fields

In this paper, we investigate the dynamics of two coupled quantum degenerate atomic fields (BEC) interacting with two classical optical fields in the nonlinear atom optics regime. Two-photon interaction produces entangled atom-atom pairs which exhibit nonclassical correlations. Since the system involves the creation of two correlated atom pairs, we call it the nondegenerate dual atomic parametric amplifier.     

pH‐Triggered Sustained Drug Delivery from a Polymer Micelle having the β‐Thiopropionate Linkage

The synthesis, micellar aggregation, and pH‐triggered intracellular drug delivery ability of an amphiphilic statistical copolymer (P2) are studied. Two methacrylate derivatives, one containing a hydrophilic pendant and the other containing a hydrophobic pendant chain, are copolymerized to produce P2. The hydrophobic pendant chain is linked to the polymer backbone by a β‐thiopropionate linkage, known to undergo slow hydrolysis at mild acidic pH. P2 forms a multimicellar cluster in water with a critical aggregation concentration of 0.02 mg mL⁻¹ and encapsulates a hydrophobic guest such as pyrene, Nile red, or the anti‐cancer drug doxorubicin (Dox). Sustained release of the entrapped Dox (80% after 100 h) is noticed at pH 5.2, while release is significantly slower (35% after 100 h) at pH 7.4. Acidic hydrolysis of the β‐thiopropionate linkage leading to the reduction of the hydrophobicity is established as the cause for micellar disassembly and triggered drug release. Cell‐culture studies with the human breast cancer cell line, MCF‐7, reveal biocompatibility of P2 (below 150 μg mL⁻¹). It is further tested for intracellular delivery of Dox. MCF‐7 cells remain healthy at pH 7.4 but become unhealthy at pH 5.2 when treated with a Dox‐loaded P2 micelles.

     

Synthesis of tetrahydroxy perhydroaza-azulenes: tandem Johnson-Claisen rearrangement of D-glucose-derived allylic alcohols

The Johnson-Claisen rearrangement of D-glucose-derived allylic alcohols 5a,b, afforded sugar-substituted gamma,delta-unsaturated ester in high yield. Conversion of the ester group to an azidomethyl group, epoxidation of the double bond and hydrogenation gave pyrrolidine ring skeletons 13a and 13b, which were transformed to tetrahydroxy perhydroaza-azulenes 1a and 1b, respectively. Glycosidase inhibitory activity was also evaluated.     

(Non-)expansivity in functional envelopes

We study expansivity in functional envelopes of dynamical systems. Our main result is that if the phase space of the original system contains an arc or if it contains a free infinite zero dimensional set, then the expansivity in the functional envelope with Hausdorff metric is impossible. This is in contrast with the fact that, when considering the uniform metric in functional envelopes, the expansivity of a system is equivalent with the expansivity of its functional envelope.     

Tolerance Factors of A2ScNbO7 (A3+ = Pr,Nd, Eu,Gd, Dy) Pyrochlore Type Oxide

Crystallography Reports - In this work, we apply the concept of tolerance factors to pyrochlore solid solution, especially when the B-site contains two different ions with different masses (as well...     

Results on L-functions and certain uniqueness questions of Gross

In this paper, we study the value distribution of L-functions in the Selberg class and concentrate on the uniqueness questions of L-functions that share one or two sets with an arbitrary meromorphic function. The results obtained in this paper improve the recent results due to Q.-Q. Yuan, X.-M. Li, and H.-X. Yi [Value distribution of L-functions and uniqueness questions of F. Gross, Lith. Math. J., 58(2):249–262, 2018] and also extend a result due to B.Q. Li [A result on value distribution of L-functions, Proc. Am. Math. Soc., 138(6):2071–2077, 2010].

     

Sourcing under incomplete information and negative capacity-cost correlation

We study a sourcing problem where a buyer reserves capacity from a set of suppliers. The suppliers have finite capacity and their unit production cost is a decreasing function of their capacity, implying scale economies. The capacity of each supplier and therefore the cost is his private information. The buyer and other suppliers only know the probability distribution of the supplier’s capacity. The buyer’s demand is random and she has to decide how much capacity to reserve in advance from a subset of suppliers and how much to source from marketplace. In this study we determine the buyer’s optimum reservation quantity and the size of the supply base. We find the presence of such capacity cost correlation leads to supply base reduction.     

UV–Vis and NMR spectroscopic investigations on effective and selective non-covalent interactions between fullerenes and calix[6]arene

Ground state non-covalent interactions between a macro cyclic calixarene receptor, namely, 4-tert-butylcalix[6]arene (1), and fullerenes (C₆₀ and C₇₀) were studied in toluene medium by absorption spectrophotometric method. Absorption band due to the charge transfer (CT) transition have been observed in the visible region between fullerenes and 1. Utilizing the CT absorption bands, various important physicochemical parameters like oscillator strength, resonance energy, transition dipole strength of the fullerene-1 complexes and ionization potential of 1 is determined in present investigations. From Jobs method of continuous variation, it is observed that both C₆₀ and C₇₀ form stable 1:1 complexes with 1. The most fascinating feature of the present study is that 1 binds selectively C₇₀ compared to C₆₀ as obtained from binding constant (K) data of C₆₀–1 (K_C60–1) and C₇₀–1 (K_C70–1) complexes, i.e., K_C60–1 = 32,400 dm³·mol^? 1 and K_C70–1 = 110,000 dm³.mol^? 1 and selectivity (K_C70–1/K_C60–1) = 3.4. ¹H NMR analysis provides very good support in favor of strong binding between C₇₀ and 1.     

Fluorescence Blinking Beyond Nanoconfinement: Spatially Synchronous Intermittency of Entire Perovskite Microcrystals

Abrupt fluorescence intermittency or blinking is long recognized to be characteristic of single nano‐emitters. Extended quantum‐confined nanostructures also undergo spatially heterogeneous blinking; however, there is no such precedent in dimensionally unconfined (bulk) materials. Herein, we report multi‐level blinking of entire individual organo–lead bromide perovskite microcrystals (volume=0.1–3 μm³) under ambient conditions. Extremely high spatiotemporal correlation (>0.9) in intracrystal emission intensity fluctuations signifies effective communication amongst photogenerated carriers at distal locations (up to ca. 4 μm) within each crystal. Fused polycrystalline grains also exhibit this intriguing phenomenon, which is rationalized by correlated and efficient migration of carriers to a few transient nonradiative traps, the nature and population of which determine blinking propensity. Observation of spatiotemporally correlated emission intermittency in bulk semiconductor crystals opens the possibility of designing novel devices involving long‐range (mesoscopic) electronic communication.