Heronapyrroles A-C: farnesylated 2-nitropyrroles from an Australian marine-derived Streptomyces sp

Chemical analysis of a marine-derived Streptomyces sp. (CMB-M0423) isolated from beach sand off Heron Island, Australia, yielded three new members of the rare pyrroloterpene biosynthetic structure class. Identified by detailed spectroscopic analysis as the first reported examples of naturally occurring 2-nitropyrroles, heronapyrroles A-C (1-3) displayed promising biological activity-with low to submicromolar IC(50) activity against Gram-positive bacteria but no cytotoxicity toward mammalian cell lines.     

Synthesis and characterization of optically active polyamides based on 2-(1,3-isoindolinedione-2-yl)glutaric acid by direct polycondensation

<正>Five new optically active polyamides(PAs) 6a-6e were prepared by direct polycondensation reaction of 2-(1,3- isoindolinedione-2-yl)-glutaric acid 4 as a new chiral diacid with various aromatic diamines 5a-5e in a medium consisting of triphenyl phosphite(TPP),calcium chloride,pyridine(Py) and N-methyl-2-pyrrolidone(NMP).The polycondensation reaction produced a series of polyamids 6a-6e in quantitative yields with inherent viscosities of 0.26-0.39 dL/g.The resulting polymers were fully characterized by means of ~1H-NMR,FT-IR spectroscopy,elemental analysis,inherent viscosity and specific rotation.Thermal properties of these polymers were investigated using thermal gravimetric analysis (TGA) and differential thermal gravimetry(DTG).Phthalimide rings as a bulky pendent group in the polymer chains disturb the interchain and intrachain interactions and make these PAs readily soluble in polar,aprotic solvents such as N,N-dimethyl acetamide(DMAc),N,N-dimethyl formamide(DMF),dimethyl sulfoxide(DMSO),N-methyl-2-pyrrolidone(NMP) and sulfuric acid.     

Synthesis and characterization of optically active poly(amide-imide)s containing photosensitive chalcone units in the main chain

<正>A series of new optically active poly(amide-imide)s were synthesized by direct polycondensation reaction of 4,4'-diaminochalcone with several N-trimellitylimido-L-amino acids using a tosyl chloride(TsCl),pyridine(Py) and dimethylformamide(DMF) system as condensing agent.The resulting thermally stable poly(amide-imide)s were obtained in good to high yields and inherent viscosities ranging between 0.35 dL/g and 0.58 dL/g and were characterized with FTIR, ~1H-NMR,CHN,Ultraviolet,TGA and DTG techniques.     

Observable T7 lepton flavor symmetry at the Large Hadron Collider

More often than not, models of flavor symmetry rely on the use of nonrenormalizable operators (in the guise of flavons) to accomplish the phenomenologically successful tribimaximal mixing of neutrinos. We show instead how a simple renormalizable two-parameter neutrino mass model of tribimaximal mixing can be constructed with the non-Abelian discrete symmetry T(7) and the gauging of B-L. This is also achieved without the addition of auxiliary symmetries and particles present in almost all other proposals. Most importantly, it is verifiable at the Large Hadron Collider.     

Four New Briarane Diterpenoids from the Gorgonian Coral Junceella fragilis

Chemical investigation of the gorgonian coral Junceella fragilis, collected by scuba diving in Taiwan, resulted in the isolation of four new briarane‐type diterpenoids, frajunolides A–D ( 1 – 4 ), along with three known briaranes. Their structures were elucidated on the basis of spectroscopic studies, especially 1‐ and 2D‐NMR as well as HR‐MS experiments. The inhibitory effect of all isolated metabolites towards superoxide‐anion generation and elastase release by human neutrophils in response to formylmethionyl‐leucyl‐phenylalanine/dihydrocytochalasin B (FMLP/CB) was evaluated.     

Some analytical results for congestion in subscriber line modules

In modern telephone exchanges, subscriber lines are usually connected to the so-called subscriber line modules. These modules serve both incoming and outgoing traffic. An important difference between these two types of calls lies in the fact that in the case of blocking due to all channels busy in the module, outgoing calls can be queued whereas incoming calls get busy signal and must be re-initiated in order to establish the required connection. The corresponding queueing model was discussed recently by Lederman, but only the model with losses has been studied analytically. In the present contribution, we study the model which takes into account subscriber retrials and investigate some of its properties such as existence of stationary regime, derive explicit formulas for the system characteristics, limit theorems for systems under high repetition intensity of blocked calls and limit theorems for systems under heavy traffic.     

Applications of ion associates for the microdetermination of vardenafil using atomic emission spectrometry

A simple, accurate, precise and sensitive method has been developed for the determination of Vardenafil (Vd) using direct coupled plasma atomic emission spectrometry. The ion associates formed as a result of the reaction of vardenafil with ammonium reineckate, Mn(II) and Co(II) thiocyanates and sodium cobaltinitrite are precipitated. The solubility of the solid complexes under the optimum conditions of pH and ionic strength was studied. Saturated solutions of each ion associate at different temperatures under the optimum precipitation conditions were prepared, and the metal ion content in the supernatant was determined. The solubility products were thus calculated at different temperatures, and the thermodynamic parameters ΔH, ΔG and ΔS were calculated. The method has been used for the determination of vardenafil (1.36–68.32 μg·mL⁻¹) in pure solutions and in Levitra tablets.     

Massera type theorem for almost automorphic solutions of functional differential equations of neutral type

In this work, we study the existence of almost automorphic solutions for functional differential equations of neutral type. We prove that the existence of a bounded solution on R⁺ implies the existence of an almost automorphic solution.     

Three New Clerodane Diterpene Derivatives from Casearia Membranacea

Three new clerodane diterpene derivatives were isolated from the leaves of Casearia membranacea Hance collected in Taiwan. The isolated metabolites were identified as caseamembrins P (1), Q (2), and R (3). Identification of the structures was based on detailed analysis of the spectral data, especially 2D NMR.