659 research outputs found

    4-[(E)-(5-Chloro-2-hydroxy­benzyl­idene)amino]benzene­sulfonamide

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    In the mol­ecule of title compound, C13H11ClN2O3S, the aromatic rings are oriented at a dihedral angle of 12.27 (3)°. An intra­molecular O—H⋯N hydrogen bond results in the formation of a planar (mean deviation 0.0083 Å) six-membered ring, which is nearly coplanar with the adjacent ring at a dihedral angle of 2.36 (13)°. In the sulfonamide group, the S atom is 0.457 (3) Å from the plane through the O and N atoms. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules

    Chronic HIV-1 Infection Frequently Fails to Protect against Superinfection

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    Reports of HIV-1 superinfection (re-infection) have demonstrated that the immune response generated against one strain of HIV-1 does not always protect against other strains. However, studies to determine the incidence of HIV-1 superinfection have yielded conflicting results. Furthermore, few studies have attempted to identify superinfection cases occurring more than a year after initial infection, a time when HIV-1-specific immune responses would be most likely to have developed. We screened a cohort of high-risk Kenyan women for HIV-1 superinfection by comparing partial gag and envelope sequences over a 5-y period beginning at primary infection. Among 36 individuals, we detected seven cases of superinfection, including cases in which both viruses belonged to the same HIV-1 subtype, subtype A. In five of these cases, the superinfecting strain was detected in only one of the two genome regions examined, suggesting that recombination frequently occurs following HIV-1 superinfection. In addition, we found that superinfection occurred throughout the course of the first infection: during acute infection in two cases, between 1–2 y after infection in three cases, and as late as 5 y after infection in two cases. Our results indicate that superinfection commonly occurs after the immune response against the initial infection has had time to develop and mature. Implications from HIV-1 superinfection cases, in which natural re-exposure leads to re-infection, will need to be considered in developing strategies for eliciting protective immunity to HIV-1

    Non-invasive single-bunch matching and emittance monitor

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    On-line monitoring of beam quality for high brightness beams is only possible using non-invasive instruments. For matching measurements, very few such instruments are available. One candidate is a quadrupole pick-up. Therefore, a new type of quadrupole pick-up has been developed for the 26 GeV Proton Synchrotron (PS) at CERN, and a measurement system consisting of two such pick-ups is now installed in this accelerator. Using the information from these pick-ups, it is possible to determine both injection matching and emittance in the horizontal and vertical planes, for each bunch separately. This paper presents the measurement method and some of the results from the first year of use, as well as comparisons with other measurement methods.Comment: 10 pages, 10 figures; added figure, minor textual additions; To be resubmitted to Phys. Rev. ST-A

    Tune measurement for the CERN proton synchrotron booster rings using DSP in VME

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    The CERN PS Booster (PSB) consists of 4 superposed rings supplied with protons from a 50 MeV Linac The CERN PS Booster (PSB) consists of 4 superposed rings supplied with protons from a 50 MeV Linac. The proton beam is then accelerated to 1 GeV and sent either to the 26 GeV Proton Synchrotron (PS) or to the ISOLDE facility. This is carried out in a multi-cycle mode every 1.2 s. For high-intensity beams, the working-point in the tune diagram needs to be changed considerably during acceleration from 50 MeV to 1 GeV and the repeated measurement of the tunes throughout the cycle is an important requirement. Up to now, tune values were obtained through calculations based on quadrupole currents. However, practical experience has shown the need for a direct tune measurement system. For this purpose, a classical kick technique is used. A fixed amplitude kick of duration equal to one revolution period excites coherent betatron oscillations. For fast treatment, a Digital Signal Processing (DSP) module in a VME-standard crate was selected. It carries out the Fast Fourier Transform (FFT) analyses of signals from position-sensitive pickups in both planes and evaluates the tunes. These measurements are carried out every 10 ms during the 450 ms acceleration ramp. The paper presents the novel features of this system, particularly the beam-offset signal suppression as well as the peak-search algorithm which yields the tune values

    Structural and Biological Behaviour of Co(II), Cu(II) and Ni(II) Metal Complexes of Some Amino Acid Derived Schiff-Bases

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    Biologically active tridentate amino acid (Alanine, Glycine & Tyrosine) derived Schiff-bases and their Co(II), Cu(II) & Ni(II) complexes have been synthesised and characterised on the basis of their conductance and magnetic measurements, elemental analysis and 13C-NMR, 1H-NMR, IR and electronic spectral data. These Schiff-bases and their complexes have been evaluated for their antibacterial activity against bacterial species such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumonae, Proteus vulgarus and Pseudomonas aeruginosa and this activity data show the metal complexes to be more antibacterial than the Schiff-bases against one or more bacterial species

    Spectral, Magnetic and Biological Studie on Some Bivalent 3d Metal Complexes of Hydrazine Derived Schiff-Base Ligands

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    Metal(II) complexes of hydrazine derived Schiff-base ligands of the type M(L)2Cl2 where M = Co, Cu, Ni and Zn and L = L1 and L2 have been prepared and characterised by molar conductance, magnetic moment, elemental analysis and electronic, IR, H-NMR and 13C spectral data.The different modes of chelation of the ligands and their comparative biological properties against different bacterial species are reported

    Estimation of blood loss during Caesarean section: an audit

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    Objective: To evaluate the blood ordering practice and blood transfusion for Caesarean sections at our institution and to compare the estimated blood loss between anaesthetists and obstetricians.Methods: A review of 126 patients undergoing both elective and emergency Caesarean section was undertaken in 2002. Information collected included the number of blood units cross-matched preoperatively, type of surgery (emergency or elective), type of anaesthesia, parity of the patient, estimated blood loss by both anaesthetists and obstetricians, intraoperative and postoperative transfusion within 48 hours and pre and post operative haemoglobin (Hb) and haemocrit (Hct).Results: A total of 215 units were cross-matched for 126 patients undergoing Caesarean section delivery. A small amount (9.5%) were transfused intraoperatively and 5.5% postoperatively. The average blood loss estimated by anaesthetists was 498 +/- 176 ml and that by obstetricians was 592 +/- 222 ml. The calculated blood loss based on patients blood volume and drop in Hct was 787 +/- 519 ml. The cross-match transfusion ratio was 9.7.CONCLUSION: Only 13% of our patients needed blood transfusion. The mean blood loss was estimated to be more by the obstetricians as compared to the anaesthetists. We recommend that the practice of routine cross-match practice prior to Caesarean section should be re-looked by institutions practicing obstetric anaesthesia

    Copper (II) Acylhydrazinates. Their Synthesis and Characterization

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    Acylhydrazine derived furanyl and thienyl Schiff bases and their Cu(II) complexes have been prepared and characterized on the basis of their physical, spectral and analytical data. The preferred enolic form of the Schiff base function as a tetradentate ligand during coordination to the metal ion yielding a square planar complex. The Schiff bases and their complexes with different anions were tested for their antibacterial activity against bacterial species such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa andKlebsiella pneumonae
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