Radiosynthesis and biological evaluation of <Superscript>99m</Superscript>TcN-sitafloxacin dithiocarbamate as a potential radiotracer for <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> infection

Sitafloxacin dithocarbamate (SFDE) was synthesized, radiolabeled with technetium-99m (^99mTc) using [^99mTc-N]²⁺ core and evaluated its biological efficacy as a potential radiotracer for Staphylococcus aureus (S. aureus) infection in artificially infected rats (AIRT) and rabbits (AIRB). The radiochemical stability of the ^99mTc labeled SFDE (^99mTcN-SFDE) in saline and serum was determined by radio-HPLC and TLC methods, respectively. After, 1 min of reconstitution the value of radiochemical purity (RCP) was 99.00 ± 0.20% and was remained more than 90% unwavering even after 240 min of the radiolabeling. The ^99mTcN-SFDE complex showed similar radiochemical permanence behavior in serum at 37 °C. The complex showed almost six fold higher specific in vitro binding with living than heat killed S. aureus. Biodistribution behavior was evaluated in S. aureus AIRT and whole body imaging (WBI) in AIRB, respectively. Seven fold up take was observed in infected muscle of the AIRT as compared to inflamed and normal muscles. The disappearance of activity from blood and appearance in urinary system indicated normal route of excretion of the complex. Scintigraphically, it was confirmed that the labeled SFDE was higher accumulated in the infected muscle higher than in inflamed and normal muscle. The high radiochemical stability in saline and serum, specific in vitro binding with S. aureus, precise in vivo distribution in S. aureus AIRT and targeted WBI in AIRB confirmed the possibility of the ^99mTcN-SFDE complex as a potential and promising S. aureus infection radiotracer.     

Controlled isoprene polymerization mediated by iminopyridine‐iron (II) acetylacetonate pre‐catalysts

A ligand controlled stereoselective polymerization of isoprene has been developed. A series of (aryl/alkyl)‐iminopyridine iron (II) acetylacetonate complexes: (aryl = Ph Fe1 ; alkyl = CH₂Ph Fe2 , CH (Ph)₂ Fe3 , CH (Me)₂ Fe4 , C (Me)₃ Fe5 , C (Me)₂CH₂C(Me)₃ Fe6 ), has been prepared in which steric and electronic substituents systematically modified to investigate their influences for isoprene polymerization. The molecular structure of representative complex Fe2 was confirmed by single crystal X‐ray diffraction and, revealed a distorted octahedral geometry at iron center. On treatment with methylaluminoxane (MAO), Fe1 – Fe6 displayed low ( Fe5 & Fe6 ) to high activities ( Fe1 – Fe4 ) with quantitative monomer conversion (>99%) for isoprene polymerization producing polyisoprene of high molecular weight (up to 2.0 × 10⁵ g/mol) and unimodal molecular weight distribution (1.4–3.3). Specifically, complex Fe2 (alkyl = CH₂Ph) displayed the highest activity of 7.0 × 10⁶ g (mol of Fe)^?1 h^?1 with 85% conversion of monomer over run time of 10 min at 25 °C. While, Fe6 catalyzed polyisoprene possessed high content of trans‐1,4 unit (up to 87%). Furthermore, the influence of the reaction parameters and the nature of the ligands on the catalytic activities and microstructural properties of the polymer were investigated in detail.     

A Conductive polylactic acid/polyaniline porous scaffold via freeze extraction for potential biomedical applications

This paper reports for the first time a simple yet effective method for fabricating a conductive and highly porous scaffold material made up of polylactic acid (PLA) and conducting polyaniline (PANI). The electrical percolation state was successfully obtained at 3 wt% of PANI inclusions and reached a conductivity level of useable tissue engineering applications at 4 wt%. In addition, preliminary bioactivity test results indicated that the protonating agent could form a chelate at the scaffold surface leading to good in-vitro apatite forming ability during biomimetic immersion. This new conductive scaffold has potential as a suitable biomedical material that requires electrical conductivity.     

Synthesis and ethylene polymerization of 8‐(fluorenylarylimino)‐5,6,7‐trihydroquinolylnickel chlorides: Tailoring polyethylenes by adjusting fluorenyl position and adduct Et2Zn

A series of 8‐(arylimino)‐5,6,7‐trihydroquinolines ligand pendant fluorenyl group at N‐aryl ring, and their nickel complexes ( Ni1 ? Ni5 ) have been prepared and characterized. Once activated with Et₂AlCl, the complexes Ni1 , Ni2 , and Ni3 bearing ligands from para‐fluorenylaniline produced unimodal polyethylenes; on the contrary complexes Ni4 and Ni5 gave bimodal polyethylenes due to steric influence of ligands from ortho‐fluorenyl anilines. With a increment of Et₂Zn/ Ni4 ratio from 0 to 400, the distinct bimodel polyethylenes were obtained with molecular weights shifted from 14.3 to 57.6 kg·mol^?1; apart shiftment to higher molecular weights, the portion of low molecular weight decreased along with higher portion of high molecular weight. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1910–1919     

Judiciously balancing steric and electronic influences on 2,3‐diiminobutane‐based Pd(II) complexes in nourishing polyethylene properties

A new series of palladium complexes ( Pd1–Pd5 ) ligated by symmetrical 2,3‐diiminobutane derivatives, 2,3‐bis[2,6‐bis{bis(4‐FC₆H₄)₂CH}₂‐4‐(alkyl)C₆H₂N]C₄H₆ (alkyl = Me L1 , Et L2 , ⁱ Pr L3 , ^t Bu L4 ) and 2,3‐bis[2,6‐bis{bis(C₆H₅)₂CH}₂‐4‐{(CH₃)₃C}C₆H₂N]C₄H₆ L5 , have been prepared and well characterized, and their catalytic scope toward ethylene polymerization have been investigated. Upon activation with MAO, all palladium complexes ( Pd1–Pd5) exhibited good activities (up to 1.44 × 10⁶ g (PE) mol^?1(Pd) h^?1) and produced higher molecular weight polyethylene in the range of 10⁵ g mol^?1 with precise molecular weight distribution (M _w/M _n = 1.37–1.77). One of the long‐standing limiting features of the Brookhart type α‐diimine Pd(II) catalysts is that they produce highly branched (ca. 100/1000 C atoms) and totally amorphous polymer. Conversely, herein Pd5 produced polymers having dramatically lower branching number (28/1000) as well as improved melting temperature up to 73.1 °C showing well‐controlled linear architecture, and very similar to polyethylene materials generated by early‐transition‐metal based catalysts. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3214–3222     

Structure cristalline de (NH4)2PO3H,H2O: Stereochimie de l'Ion PO3H2− et ses relations avec PO3F2− et SO32−

(NH₄)₂PO₃H, H₂O crystallizes in the monoclinic system, space group P2₁/c, with a = 6.322(1) Å, b = 8.323(1) Å, c = 12.676(1) Å, β = 98.84(1) and Z = 4. The structure was refined to R = 0.022 based on 853 independent X-Rays intensities. Improved dimensions of the tetrahedral PO₃H^2? ion have been obtained: P?H = 1.34(2) and P?O = 1.514(2) Å. The geometry of this ion is compared with that of PO₃F^2? and SO₃^2? ions and we find a decrease of the volume: V_F? > V_H+ > V_{lone pair}.     

Pyridine Scaffolds,Phenols and Derivatives of Azo Moiety: Current Therapeutic Perspectives

Synthetic heterocyclic compounds have incredible potential against different diseases; pyridines, phenolic compounds and the derivatives of azo moiety have shown excellent antimicrobial, antiviral, antidiabetic, anti-melanogenic, anti-ulcer, anticancer, anti-mycobacterial, anti-inflammatory, DNA binding and chemosensing activities. In the present review, the above-mentioned activities of the nitrogen-containing heterocyclic compounds (pyridines), hydroxyl (phenols) and azo derivatives are discussed with reference to the minimum inhibitory concentration and structure–activity relationship, which clearly indicate that the presence of nitrogen in the phenyl ring; in addition, the hydroxyl substituent and the incorporation of a diazo group is crucial for the improved efficacies of the compounds in probing different diseases. The comparison was made with the reported drugs and new synthetic derivatives that showed recent therapeutic perspectives made in the last five years.     

Development of porous,antibacterial and biocompatible GO/n-HAp/bacterial cellulose/β-glucan biocomposite scaffold for bone tissue engineering

Due to their potential renewable materials-based tissue engineering scaffolds has gained more attention. Therefore, researchers are looking for new materials to be used as a scaffold. In this study, we have focused on the development of a nanocomposite scaffold for bone tissue engineering (using bacterial cellulose (BC) and β-glucan (β-G)) via free radical polymerization and freeze-drying technique. Hydroxyapatite nanoparticles (n-HAp) and graphene oxide (GO) were added as reinforcement materials. The structural changes, surface morphology, porosity, and mechanical properties were investigated through spectroscopic and analytical techniques like Fourier transformation infrared (FT-IR), scanning electron microscope (SEM), Brunauer–Emmett-Teller (BET), and universal testing machine Instron. The scaffolds showed remarkable stability, aqueous degradation, spongy morphology, porosity, and mechanical properties. Antibacterial activities were performed against gram -ive and gram + ive bacterial strains. The BgC-1.4 scaffold was found more antibacterial compared to BgC-1.3, BgC-1.2, and BgC-1.1. The cell culture and cytotoxicity were evaluated using the MC3T3-E1 cell line. More cell growth was observed onto BgC-1.4 due to its uniform interrelated pores distribution, surface roughness, better mechanical properties, considerable biochemical affinity towards cell adhesion, proliferation, and biocompatibility. These nanocomposite scaffolds can be potential biomaterials for fractured bones in orthopedic tissue engineering.