Tunable wavelength division multiplexing channel isolation filter based on dual chirped long-period fiber gratings

We propose and demonstrate a wavelength tunable wavelength division multiplexing channel isolation filter based on two concatenated chirped long-period fiber gratings (LPGs). An intergrating space (IGS), deliberately introduced between the two gratings, provides an extra phase difference between the core and cladding modes. Changing this phase by heating the IGS without affecting the gratings tunes the channels. A theoretical account of the filter action is also presented and the results are found to be in excellent agreement with the experiments. Unlike the filters based on normal concatenated chirped LPGs without an IGS, the current filter shows a linear tuning over an increased spectral range.     

Vector valued bilinear maximal operator and method of rotations

In this paper we obtain a bilinear analogue of Fefferman-Stein?s vector valued inequality for classical Hardy-Littlewood maximal function. Also, we prove the boundedness of bilinear Hardy-Littlewood maximal operator from Lp₁(Rn)×Lp₂(Rn)→L¹(Rn), where , by applying the method of rotations.     

Mechanical response of multicrystalline thin films in mesoscale field dislocation mechanics

A continuum model of plasticity, Phenomenological Mesoscopic Field Dislocation Mechanics (PMFDM), is used to study the effect of surface passivation, grain orientation, grain boundary constraints, and film thickness on the mechanical response of multicrystalline thin films. The numerical experiments presented in this paper show that a surface passivation layer on thin films introduces thickness dependence of the mechanical response. However, the effect of passivation decreases in films with impenetrable grain boundaries. The orientation of individual grains of the multicrystal also has a significant effect on the mechanical response. Our results are in qualitative agreement with experimental observations. A primary contribution of this work is the implementation of a jump condition that enables the modeling of important limits of grain boundary constraints to plastic flow, independent of ad-hoc constitutive assumptions and interface conditions.     

Structural diversity for phosphine complexes of stibenium and stibinidenium cations

Reactions of trimethylphosphine or diphosphines with SbCl(3) in the presence of AlCl(3) or Me(3)SiSO(3)CF(3) give ligand stabilized stibenium and stibinidenium cations. The geometry at each antimony center reveals a variety of environments for antimony that describes new bonding and highlights new directions in the chemistry of the pnictogen elements.     

Molecular Dynamic and Docking Interaction Study of Heterodera glycines Serine Proteinase with Vigna mungo Proteinase Inhibitor

Many plants do produce various defense proteins like proteinase inhibitors (PIs) to protect them against various pests. PIs function as pseudosubstrates of digestive proteinase, which inhibits proteolysis in pests and leads to amino acid deficiency-based mortality. This work reports the structural interaction studies of serine proteinase of Heterodera glycines (SPHG) with Vigna mungo proteinase inhibitor (VMPI). 3D protein structure modeling, validation of SPHG and VMPI, and their putative protein–protein binding sites were predicted. Protein–protein docking followed by molecular dynamic simulation was performed to find the reliable confirmation of SPHG–VMPI complex. Trajectory analysis of each successive conformation concludes better interaction of first loop in comparison with second loop. Lysine residues of first loop were actively participating in complex formation. Overall, this study discloses the structural aspects and interaction mechanisms of VMPI with SPHG, and it would be helpful in the development of pest-resistant genetically modified crops.     

Microwave Assisted Synthesis of Poly(ether sulfone) – An Efficient Synthetic Route to Control Polymer Chain Structure

A novel synthetic process for the efficient control over molecular weight of the poly(ether sulfone) has been studied. The application of microwave irradiation for the condensation polymerization to synthesize poly(ether sulfone) is demonstrated. Microwave assisted polymerization results in significant reduction of reaction time. Microwave based process is also feasible at lower temperature for the synthesis of poly(ether sulfone). Polymers synthesized have been characterized using NMR and FTIR spectroscopy. Polymer film morphology and surface composition have been studied using SEM and EDX. An increase in the molecular weight is observed with increasing microwave irradiation time.     

Solvent sensitivity of ortho substituent effect on 13C NMR chemical shift of the carboxyl carbon (δco) in benzoic acid

A reverse ortho effect is observed for the (13)C NMR chemical shifts of the carboxyl carbon (δ(co)) in benzoic acids measured in aprotic solvents of varying polarity. The ortho effect on δ(co) is best described by a combination of the reverse field and steric accelerating effects of the substituent in an 80: 20 pattern in apolar aprotic solvents and a 60: 40 pattern in dipolar aprotic ones. Interestingly, no good enough correlation was found between δ(co) and log k(1) of the acids measured in similar solvents. A critical analysis of the results clearly indicates the use of an apolar aprotic solvent and not a dipolar aprotic one as the solvent of choice for investigating intrinsic substituent effects on δ(c) in an aromatic system.     

Simple analytical model of a thermal diode

Recently there is a lot of attention given to manipulation of heat by constructing thermal devices such as thermal diodes, transistors and logic gates. Many of the models proposed have an asymmetry which leads to the desired effect. Presence of non-linear interactions among the particles is also essential. But, such models lack analytical understanding. Here we propose a simple, analytically solvable model of a thermal diode. Our model consists of classical spins in contact with multiple heat baths and constant external magnetic fields. Interestingly the magnetic field is the only parameter required to get the effect of heat rectification.     

Debye temperature and melting point of II‐VI and III‐V semiconductors

In this paper, simple relations are proposed for the calculation of Debye temperature θ_D and melting point T_mof II‐VI and III‐V zincblende semiconductors. Six relations are proposed to calculate the value of θ_D. Out of these six relations, two are based on plasmon energy data and the others on molecular weight, melting point, ionicity and energy gap. Three simple relations are proposed to calculate the value of T_m. They are based on plasmon energy, molecular weight and ionicity of the semiconductors. The average percentage deviation of all nine equations was calculated. In all cases, except one, it was estimated between 3.34 to 17.42 % for θ_D and between 2.37 to 10.45 % for T_m. However, in earlier correlations, it was reported between 10.59 to 33.38% for θ_D and 6.96 to 14.95% for T_m. The lower percentage deviation shows a significant improvement over the empirical relations proposed by earlier workers. The calculated values of θ_D and T_m from all equations are in good agreement with the available experimental values and the values reported by different workers. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Self-assembled neutral and ionic [2 + 2] metallomacrocycles using a new flexible ditopic Pt(II)-based organometallic tecton bearing a pyrimidine motif: Facile syntheses and enhanced anticancer potency

A new di-platinum(II) organometallic compound ( 3 ) has been synthesized from a readily available pyrimidine derivative in two steps. 3 is a conformationally flexible molecule due to the presence of ethereal linkages. The application of 3 as an acceptor tecton in supramolecular chemistry was explored using coordination-driven self-assembly protocol. Thus, three neutral ( M ₁ – M ₃ ) and two ionic ( M ₄ and M ₅ ) metallomacrocycles were obtained in high yields, the structures of which included biologically active pyrimidine and π-conjugated trans-Pt(II)-alkynyl motifs. Formation of these five flexible [2 + 2] ensembles ( M ₁ – M ₅ ) was confirmed using FT-IR and NMR spectroscopy (¹H, ³¹P{¹H}, ¹³C{¹H}, and ¹H DOSY) as well as HRMS experiments. DFT calculations suggest that the macrocycles have nano-scalar dimensions with well-defined cavities. Cytotoxicity of 3 and macrocycles ( M ₁ – M ₅ ) were estimated against A549 human lung cancer cell line. Results indicate improvement in cytotoxicity upon self-assembly of 3 with neutral and ionic donor tectons to yield, respectively ionic and neutral macrocycles ( M ₁ – M ₅ ). Although the organometallic molecule 3 is almost seven times more potent than cisplatin, the antiproliferative potencies of the macrocycles ( M ₁ – M ₅ ) are up to 17 times better than cisplatin. Annexin V-FITC assay studies show that post-treatment with the organometallic 3 , or the macrocycles ( M ₁ – M ₅ ), the A549 cancer cells are present in the early apoptosis stage.