114 research outputs found
Utility of lytic bacteriophage in the treatment of multidrug-resistant <i> Pseudomonas aeruginosa</i> septicemia in mice
No full textDrug resistance is the major cause of increase in morbidity and mortality in neonates. One thousand six hundred forty-seven suspected septicemic neonates were subjected for microbiological analysis over a period of 5 years. Forty-two P. aeruginosa were isolated and the antibiogram revealed that 28 P. aeruginosa were resistant to almost all the common drugs used (multidrug-resistant). The emergence of antibiotic-resistant bacterial strains is one of the most critical problems of modern medicine. As a result, a novel and most effective approaches for treating infection caused by multidrug-resistant bacteria are urgently required. In this context, one intriguing approach is to use bacteriophages (viruses that kill bacteria) in the treatment of infection caused by drug-resistant bacteria. In the present study, the utility of lytic bacteriophages to rescue septicemic mice with multidrug-resistant (MDR) P. aeruginosa infection was evaluated. MDR P. aeruginosa was used to induce septicemia in mice by intraperitoneal (i.p.) injection of 10 7 CFU. The resulting bacteremia was fatal within 48 hrs. The phage strain used in this study had lytic activity against a wide range of clinical isolates of MDR P. aeruginosa. A single i.p. injection of 3 x 10 9 PFU of the phage strain, administered 45 min after the bacterial challenge, was sufficient to rescue 100% of the animals. Even when treatment was delayed to the point where all animals were moribund, approximately 50% of them were rescued by a single injection of this phage preparation. The ability of this phage to rescue septicemic mice was demonstrated to be due to the functional capabilities of the phage and not to a nonspecific immune effect. The rescue of septicemic mice could be affected only by phage strains able to grow in vitro on the bacterial host used to infect the animals and when such strains are heat-inactivated, they lose their ability to rescue the infected mice. Multidrug-resistant bacteria have opened a second window for phage therapy. It would seem timely to begin to look afresh at this approach. A scientific methodology can make phage therapy as a stand-alone therapy for infections that are fully resistant to antibiotics
Complex scattering potential – ionization contribution (CSP-ic) method for calculating total ionization cross sections on electron impact
No full textIn this article, we report calculations of total
ionization cross sections, Qion, for simple atoms (C, N, O, F) and
molecules (NO and NH of atmospheric interest on electron impact at
energies from threshold to 2000 eV. We have employed the complex scattering
potential – ionization contribution (CSP-ic) method for the present study.
Attempt has been made to improve the method by computing the parameter that
involves the ratio of sum of the total excitation cross sections
(Σ Qexc) and total inelastic cross section (Qinel) at the peak of the
inelastic cross section. The present study not only provided a better
estimation of the parameter involved in the CSP-ic method but also provided
better agreement with the available experimental and theoretical data on the
ionization cross sections of the simple atomic and molecular targets studied
here
Single heavy flavour baryons using Coulomb plus a power law interquark potential
No full textProperties of single heavy flavor baryons in a non-relativistic potential model with colour Coulomb plus a power law confinement potential have been studied using a simple variational method. The ground-state masses of single heavy baryons and the mass difference between the J
P =
+ and J
P =
+ states are computed using a spin-dependent two-body potential. Using the spin-flavour structure of the constituting quarks and by defining an effective confined mass of the constituent quarks within the baryons, the magnetic moments are computed. The masses and magnetic moments of the single heavy baryons are found to be in accordance with the existing experimental values and with other theoretical predictions. It is found that an additional attractive interaction of the order of -200 MeV is required for the antisymmetric states of (Q
c, b) . It is also found that the spin-hyperfine interaction parameters play a decisive role in hadron spectroscopy
Tetraquark states in the bottom sector and the status of the Y b (10890) state
No full textWe have performed an exploratory study of bottom tetraquarks () in the diquark–antidiquark framework with the inclusion of spin hyperfine, spin–orbit and tensor components of the one gluon exchange interaction. Our focus here is on the (10890) and other exotic states in the bottom sector. We have predicted some of the bottom counterparts to the charm tetraquark candidates. Our present study shows that if and are diquark–diantiquark states then they have to be first radial excitations only and we have predicted the state as first radial excitation of tetraquark state (10.143–10.230). We have identified state with as being the analog of . The observation of the will provide a deeper insight into the exotic hadron spectroscopy and is helpful to unravel the nature of the states connected by the heavy quark symmetry. We particularly focus on the lowest P-wave states with by computing their leptonic, hadronic, and radiative decay widths to predict the status of the still controversial (10890) state. Apart from this, we have also shown here the possibility of mixing of P-wave states. In the case of mixing of the state with different spin multiplicities, we found that the predicted masses of the mixed P states differ from the (10890) state only by MeV energy difference, which can be helpful to resolve further the structure of (10890)
Mass spectra of four-quark states in the hidden charm sector
No full textMasses of the low-lying four-quark states in the hidden charm sector ( are calculated within the framework of a non-relativistic quark model. The four-body system is considered as two two-body systems such as diquark-antidiquark ( -
and quark-antiquark-quark-antiquark ( -
q molecular-like four-quark states. Here, the Cornell-type potential has been used for describing the two-body interactions among Q -q , - , Q - , Qq - and Q
-
q , with appropriate string tensions. Our present analysis suggests the following exotic states: X(3823) , Z
c(3900) , X(3915) , Z
c(4025) , (4040) , Z
1(4050) and X(4160) as Q
-
q molecular-like four-quark states, while Z
c(3885) , X(3940) and Y(4140) as the diquark-antidiquark four-quark states. We have been able to assign the JPC values for many of the recently observed exotic states according to their structure. Apart from this, we have identified the charged state Z(4430) recently confirmed by LHCb as the first radial excitation of Zc(3885) with G = + 1 and Y(4360) state as the first radial excitation of Y(4008) with G = - 1 and the state as the first radial excitation of the state
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