Candidates for twin chiral bands in 102Rh.

Excited states in 102Rh, populated in the fusion-evaporation reaction Zr94(11B,3n)102Rh at a beam energy of 36 MeV, were studied using the Indian National Gamma Array spectrometer at Inter University Accelerator Center, New Delhi. The angular correlations and the electromagnetic character of some of the gamma-ray transitions observed were investigated in detail. A new chiral candidate sister band was found. Lifetimes of exited states in both chiral candidate bands of 102Rh were measured for the first time in the A∼100 mass region by means of the Doppler-shift attenuation technique. The derived reduced transition probabilities are compared to the predictions of the two quasiparticles plus triaxial rotor model. Both experimental results and calculations do not support the presence of static chirality in 102Rh.

Ultrahigh-resolution γ-ray spectroscopy of 156Gd: a test of tetrahedral symmetry.

Tetrahedral symmetry in strongly interacting systems would establish a new class of quantum effects at subatomic scale. Excited states in 156Gd that could carry the information about the tetrahedral symmetry were populated in the 155Gd(n,γ)156Gd reaction and studied using the GAMS4/5 Bragg spectrometers at the Institut Laue-Langevin. We have identified the 5(1)- → 3(1)- transition of 131.983(12) keV in 156Gd and determined its intensity to be 1.9(3)x10(-6) per neutron capture. The lifetime τ=220(-30)(+180) fs of the 5(1)- state in 156Gd has been measured using the GRID technique. The resulting B(E2)=293(-134)(+6) Weisskopf unit rate of the 131.983 keV transition provides the intrinsic quadrupole moment of the 5(1)- state in 156Gd to be Q0=7.1(-1.6)(+0.7) b. This large value, comparable to the quadrupole moment of the ground state in 156Gd, gives strong evidence against tetrahedral symmetry in the lowest odd-spin, negative-parity band of 156Gd.

Coherent contributions to isospin mixing in the mirror pair 67As and 67Se.

Isospin symmetry breaking has been investigated in mass A=67 mirror nuclei through the experimental determination of the E1 strengths of analog electromagnetic transitions. Lifetimes of excited states have been measured in (67)Se and (67)As with the centroid shift method. Through the comparison of the B(E1) strengths of the mirror 9/2(+)-->7/2(-) transitions, the isovector and the isoscalar components of the electromagnetic transition amplitude were extracted. The presence of a large isoscalar component provides evidence for coherent contributions to isospin mixing, probably involving the isovector giant monopole resonance.

Transition probabilities in 134Pr: a test for chirality in nuclear systems.

Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F,4n)134Pr. Recoil distance Doppler-shift and Doppler-shift attenuation measurements using the Euroball spectrometer, in conjunction with the inner Bismuth Germanate ball and the Cologne plunger, were performed at beam energies of 87 MeV and 83 MeV, respectively. Reduced transition probabilities in 134Pr are compared to the predictions of the two quasiparticle + triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134Pr can be supported.

Effective charges in the fp shell.

Following the heavy-ion fusion-evaporation reaction 32S+24Mg at 95 MeV beam energy the lifetimes of analogue states in the T(z)=+/-1/2 A=51 mirror nuclei 51Fe and 51Mn have been measured using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The deduced B(E2;27/2(-)-->23/2(-)) values afford a unique opportunity to probe isoscalar and isovector polarization charges and to derive effective proton and neutron charges, epsilon(p) and epsilon(n), in the fp shell. A comparison between the experimental results and several different large-scale shell-model calculations yields epsilon(p) approximately 1.15e and epsilon(n) approximately 0.80e.

Coulomb energy differences in t = 1 mirror rotational bands in (50)Fe and (50)Cr.

Gamma rays from the N = Z-2 nucleus (50)Fe have been observed, establishing the rotational ground state band up to the state J(pi) = 11+ at 6.994 MeV excitation energy. The experimental Coulomb energy differences, obtained by comparison with the isobaric analog states in its mirror (50)Cr, confirm the qualitative interpretation of the backbending patterns in terms of successive alignments of proton and neutron pairs. A quantitative agreement with experiment has been achieved by exact shell model calculations, incorporating the differences in radii along the yrast bands, and properly renormalizing the Coulomb matrix elements in the pf model space.

[Changing susceptibility patterns of surgical site infection pathogens after the introduction of modern perioperative chemotherapy in the emergency surgery clinic]. / Promeni v chuvstvitelnostta na prichinitelite na raneva infektsiia sled vuvezhdaneto na suvremenna perioperativna khimioprofilaktika v klinikata po speshna khirurgiia.

993 surgical site infection aerobic pathogens are isolated over a six-year period (I.1994-I.2000) by the Microbiology Laboratory at University Hospital "Tzaritza Joana". 224 (22.6%) of them are isolated from patients undergoing abdominal surgery in the Emergency Surgery Clinic. The period covers 3 years before the introduction of current single-dose perioperative prophylaxis (i.e. under the conditions of long-term one) as well as the next 3 years following its introduction in the Emergency Surgery Clinic. The changes of pathogens susceptibility patterns to single-dose drug schemes in both hospital elective abdominal surgery and emergency surgery clinics are followed during the whole period. Our microbial susceptibility data support the ecological expedience of single-dose approach categorically.

[Our experience in introducing current antibiotic prophylaxis into abdominal surgery--the initial results]. / Nashiiat opit pri vuvezhdane na suvremenna antibiotichna profilaktika v koremnata khirurgiia--nachalni rezultati.

Over a one-year period (Nov. 1996-Nov. 1997), a total of 154 patients are admitted on an emergency basis, with deferred emergency and for routine treatment in the Clinic of Emergency Surgery. They are distributed in three groups, as follows: patients not requiring perioperative antibiotic prophylaxis and postoperative antibiotic therapy--27, patients subjected to perioperative parenteral antibiotic prophylaxis under adequate hospital conditions--121, and patients undergoing antibiotic prophylaxis in conditions inappropriate for its application--six. The drug schemes elaborated are in conformity with worldwide and Bulgarian experience along this line, and with the concrete hospital and economical conditions in this country. In all patient indicated for antibiotic prophylaxis the listed below antibacterial agents (presented as drug schemes) are administered i.v. a single time prior to anesthesia induction: in operations on the gastrointestinal tract except for interventions in acute appendicitis: cephalotin/cefazolin 2.0 g and metronidazole 0.5 g i.v.; in operations for acute appendicitis: amoxicillin/clavulanate 1.2 g and petronidazole 0.5 f i.v.; biliary surgery free of extrahepatic cholestasis: cephalotin/cefazolin 2.0 g i.v.; biliary surgery with present or preceding extrahepatic cholestasis: cefotetan 2 g i.v.; contaminated liver cysts (parasitic and nonparasitic): cefotetan 2 g i.v.; abdominal trauma without perforation of a hollow organ: cefotetan 2 g i.v.; in plastic repair of the anterior abdominal wall (congenital defects, postoperative eventration) and in poor risk patients (local and general status: cephalotin/cefazolin 2.0 g i.v. In 135 patients the postoperative period runs a course free of complications worthy of notice. Complications directly linked to introduction of the method proposed are recorded in ten cases: operative wound suppuration (4) and hospital infection (6). Complications not related directly to the procedure are observed in nine cases: urinary tract infection (4), bronchopneumonia (2), fever with unknown source of infection (including negative hemoculture) necessitating additional antibiotic therapy (2) and secondary infection (within a week of intervention) necessitating further therapy with antibiotics. The specific features of antibiotic prophylaxis used in the various types of operative interventions are discussed from microbiological, clinical and pharmacotherapeutic viewpoints. The obtained results are compared with pertinent literature data on the issue with a special reference to the clinical efficacy attained. They mirror the approach against the background of the concrete hospital conditions in this country. The method developed is fully consistent with the level of surgical expertise in Bulgaria. All efforts should be aimed at intrahospital environment improvement by means of meticulous asepsis and antisepsis.

[Current antibiotic prophylaxis in colorectal surgery]. / Suvremenna antibiotichna profilaktika v kolorektalnata khirurgiia.

Over a one-year period (November 1996 to November 1997), in the Emergency Surgery Clinic perioperative parenteral antibiotic prophylaxis during colorectal operations is performed in a series of 32 patients, admitted on an emergency and deferred urgency basis, or for routine operative treatment. Of them 30 present malignant processes involving colon and rectum, and two--inflammatory diseases. All patients receive single i.v. injections with Cephalothin/Cefazolin at dose 2.0 g and Metronidazole 0.5 g immediately after anesthesia induction. In nine cases additional early treatment is necessitated--within 24 hours after the operative intervention--by administration of the same drug combination 4 times at 6-hour intervals, and in another two prophylaxis is substituted for continuous 5-day treatment using the same therapeutic scheme. In 30 patients the postoperative period runs a course free of noteworthy complications. In two instances there is evidence of operative wound suppuration, and in further two--urinary tract infection development unrelated to the antibiotic prophylaxis applied. The specific features characterizing the application of antibiotic prophylaxis during colorectal surgery are discussed, and appropriate drug therapy schemes are recommended, consistent with worldwide and Bulgarian experience along this line, as well as with the concrete hospital and economical conditions in this country. Special emphasis is laid on two aspects: optimization of the timing of antibiotic agent/agents injection, and reaching peak serum and tissue bactericidal concentrations in the immediate vicinity of the surgical incision; optimization of the duration of antibiotic prophylaxis on the ground of well established indications for the application of antibiotic prophylaxis in colorectal surgery in compliance with the dynamic patterns of intra- and postoperative septic risk. The modest number of patients subjected to updated parenteral perioperative antibiotic prophylaxis does not warrant a definitive interpretation of the data from the comparative clinical and pharmaco-economical analyses performed. Nevertheless, the preliminary results point to the economical expedience of the therapeutic approach suggested.

[Anaerobic surgical infection and septic shock]. / Anaerobna khirurgichna infektsiia i septichen shok.

In the period 1990 through 1995, one-hundred patients operated for acute abdomen or admitted on a routine basis, presenting evidence of anaerobic infection, undergo treatment in the clinic of emergency surgery. Septic shock develops in 10/100 patients (10 per cent). In six of the latter the outcome is fatal--three with infection caused by spore-forming anaerobes (gas gangrene of the inguinal region--of Fournier, and anterior abdominal wall--anus praeternaturalis--two), and three with infection caused by non-spore-forming anaerobes (mixed anaerobic-aerobic infection). Anaerobic surgical infection and septic shock specificity is discussed, with an algorithm of therapeutic approach, based on clinical experience had with 100 patients, being proposed in either of them. Special emphasis is laid on antibiotic prophylaxis against anaerobic surgical infection. Its implementation in the concrete clinical conditions in this country demands a clearcut hospital drug policy (adoption of the "Drug Formularies" system), and elaboration of a new economical approach to the choice of antibacterial agents (using some of the forms of pharmaco-economical analysis, practicable with a view to the Bulgarian health-care model).

[The clinical use of lincomycin in treating anaerobic infection in patients with surgical abdomen]. / Klinichno prilozhenie na linkomitsin pri lechenie na anaerobna infektsiia pri bolni s khirurgichen korem.

Experience is recorded with lincomycin treatment of 59 patients with acute surgical abdomen. The primary anaerobic flora was eradicated in 86 per cent of the patients. For the very good therapeutic results essential was the early instituted adequate antibiotic therapy in adequate dose and for adequate length of time.