Chromatic and opto-mechanical dispersion of some characteristic parameters of optical fiber undergoing macrobending

Bending of optical fiber leads to an induced-anisotropy in the index profile that influences many important guiding fiber parameters. An analytical method is described for the measurement of refractive-index-wavelength dispersion in bent optical fibers. Multiple-beam Fizeau fringes technique at transmission is used to analyze the opto-mechanical properties and induced-index anisotropy in a standard single-mode fiber undergoes pure mechanical macrobending. The shift in Fizeau fringes is employed to evaluate the dispersion of the cladding material of the bent fiber. The radial variations in Cauchy’s coefficients and the associated variations of some fiber parameters due to macrobending are carried out. The radial profiles of some material parameters such as oscillation energy, dispersion energy, lattice energy and material dispersion are measured as well. The presented method is capable to achieve quantitative and qualitative measurements, which is not available with other methods. The method has a good index resolution in the order of 10⁻⁴ and spatial resolution of 1.3 μm.     

A note on the two-stage hybrid flow shop problem with dedicated machines

In this paper we introduce a new dominance rule for the two-stage hybrid flow shop problem with dedicated machines. The rule is then used to construct a dominating set. The efficiency of the proposed rule is shown through an analysis of the dominating set cardinality.     

Attraction behaviour of Anagrus nilaparvatae to remote lemongrass (Cymbopogon distans) oil and its volatile compounds

Utilisation of Anagrus nilaparvatae is a promising and effective method for planthoppers manipulation. Twenty-seven components of remote lemongrass (Cymbopogon distans) oil were identified by GC/MS and nine volatiles were selected for behavioural experiments. In this study, we noted that the remote lemongrass oil was attractive to female A. nilaparvatae at concentrations of 0.1 and 1 mg/L. α-Pinene, β-pinene, eucalyptol, carveol and D-carvone attracted female wasps in the dose-dependent bioassays. Blend 1 (a mixture of eucalyptol, D-carvone, carveol, α-pinene, and β-pinene with ratios of remote lemongrass oil volatiles of 625:80:11:5:3) attracted female wasps at 10 mg/L, while blend 2 (a mixture of the same five volatiles at the same loading ratio) attracted them at 0.1 and 1 mg/L. These results suggested that plant essential oils could be attractants for natural enemies to control pests. The ratios of volatiles in the mixtures affect the attractiveness of the synthetic mixtures.     

Disappearing Polymorphs in Metal–Organic Framework Chemistry: Unexpected Stabilization of a Layered Polymorph over an Interpenetrated Three-Dimensional Structure in Mercury Imidazolate

The “disappearing polymorph” phenomenon is well established in organic solids, and has had a profound effect in pharmaceutical materials science. The first example of this effect in metal-containing systems in general, and in coordination-network solids in particular, is here reported. Specifically, attempts to mechanochemically synthesize a known interpenetrated diamondoid (dia) mercury(II) imidazolate metal–organic framework (MOF) yielded a novel, more stable polymorph based on square-grid (sql) layers. Simultaneously, the dia-form was found to be highly elusive, observed only as a short-lived intermediate in monitoring solvent-free synthesis and not at all from solution. The destabilization of a dense dia-framework relative to a lower dimensionality one is in contrast to the behavior of other imidazolate MOFs, with periodic density functional theory (DFT) calculations showing that it arises from weak interactions, including structure-stabilizing agostic C−H⋅⋅⋅Hg contacts. While providing a new link between MOFs and crystal engineering of organic solids, these findings highlight a possible role for agostic interactions in directing topology and stability of MOF polymorphs.     

Cyclodesulfurization of Substituted Thiosemicarbazides into 1,3,4-Oxadiazoles via Hydrazonoyl Chlorides

Abstract

The reaction of thiosemicarbazides 1a–h with hydrazonoyl chlorides 2a–g at ambient temperature, in the presence of triethylamine yielded, in each case, two products. The structure of these compounds was confirmed as 1,3,4-oxadiazoles 14a–h and hydrazonothioates 15a–g. The structure of 15b was confirmed through single crystal X-ray diffraction. A mechanism was proposed for this cyclodesulfurization reaction.     

Dipolar Cycloaddition Reactions with Thiazolonylhydrazones: A New Route for the Synthesis of Several New Thienyl- and Furyl-Thiazolonylpyrrolopyrazole Derivatives of Expected Biological Activities

Several new pyrrolopyrazoles were synthesized via the reactions of each of 2-thiophenecarboxaldehyde thiazolonylhydrazone or 2-furaldehyde thiazolonylhydrazone with N -substituted maleimides followed by partial dehydogenation using bromobenzene and complete aromatization using nitrobenzene. Structures were established on the basis of elemental analyses and spectroscopic data studies.     

Studies on 2-Aminothiophenes: Synthesis,Transformations, and Biological Evaluation of Functionally-Substituted Thiophenes and Their Fused Derivatives

Abstract

Heterocyclic enamines1 reacted with ethyl acetoacetate to afford the corresponding amide derivatives2. Treatment of2 with carbon disulphide yielded the dipotassium salts3which reacted in-situ with a variety of α -haloketones to give the respective substituted thiophenes5,8, and13. The reactivity of the latter products towards various chemical reagents was studied to yield their fused thiophene derivatives7,10,12, and14, respectively. Some representative compounds were tested for antimicrobial activity.     

Link between perpendicular coupling and exchange biasing in Fe(3)O(4)/CoOMultilayers

In studying well-characterized, exchange-biased Fe(3)O(4)/CoO superlattices, we demonstrate a causal link between the exchange bias effect and the perpendicular coupling of the ferrimagnetic and antiferromagnetic spins. Neutron diffraction studies reveal that for thin CoO layers the onset temperature for exchange biasing T(B) matches the onset of locked-in, preferential perpendicular coupling of the spins, rather than the antiferromagnetic ordering temperature T(N). The results are explained by considering the role of anisotropic exchange first proposed by Dzyaloshinsky and Moriya and developing a model based purely on information on structural defects and exchange for these oxides. The devised mechanism provides a general explanation of biasing in systems with perpendicular coupling.     

Deciphering the Role of Filamin B Calponin-Homology Domain in Causing the Larsen Syndrome,Boomerang Dysplasia,and Atelosteogenesis Type I Spectrum Disorders via a Computational Approach

Filamins (FLN) are a family of actin-binding proteins involved in regulating the cytoskeleton and signaling phenomenon by developing a network with F-actin and FLN-binding partners. The FLN family comprises three conserved isoforms in mammals: FLNA, FLNB, and FLNC. FLNB is a multidomain monomer protein with domains containing an actin-binding N-terminal domain (ABD 1–242), encompassing two calponin-homology domains (assigned CH1 and CH2). Primary variants in FLNB mostly occur in the domain (CH2) and surrounding the hinge-1 region. The four autosomal dominant disorders that are associated with FLNB variants are Larsen syndrome, atelosteogenesis type I (AOI), atelosteogenesis type III (AOIII), and boomerang dysplasia (BD). Despite the intense clustering of FLNB variants contributing to the LS-AO-BD disorders, the genotype-phenotype correlation is still enigmatic. In silico prediction tools and molecular dynamics simulation (MDS) approaches have offered the potential for variant classification and pathogenicity predictions. We retrieved 285 FLNB missense variants from the UniProt, ClinVar, and HGMD databases in the current study. Of these, five and 39 variants were located in the CH1 and CH2 domains, respectively. These variants were subjected to various pathogenicity and stability prediction tools, evolutionary and conservation analyses, and biophysical and physicochemical properties analyses. Molecular dynamics simulation (MDS) was performed on the three candidate variants in the CH2 domain (W148R, F161C, and L171R) that were predicted to be the most pathogenic. The MDS analysis results showed that these three variants are highly compact compared to the native protein, suggesting that they could affect the protein on the structural and functional levels. The computational approach demonstrates the differences between the FLNB mutants and the wild type in a structural and functional context. Our findings expand our knowledge on the genotype-phenotype correlation in FLNB-related LS-AO-BD disorders on the molecular level, which may pave the way for optimizing drug therapy by integrating precision medicine.