Early outcome of Mitral Valve replacement: Results from Chordal Preservation at Muhimbiba National Hospital, Tanzania

No Abstrac

Prevalence of clindamycin inducible resistance among methicillin-resistant Staphylococcus aureus at Bugando Medical Centre, Mwanza, Tanzania

Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) has been recognized world wide as an important causative agent of nosocomial and community acquired infections. Clindamycin has been considered as analternative drug for the treatment of such strains. However, the possibility of clindamycin inducible resistance complicates the choice of treatment. The aim of this study was to determine the prevalence of clindamycininducible resistance of MRSA at Bugando Medical Centre (BMC) in Mwanza Tanzania. A total of 600 clinical specimens of pus, wound swabs and aspirates from patients admitted at BMC surgical wards were processedover a period of 4 months. Of these, 160 of S. aureus clinical isolates were analysed. MRSA was identified using cefoxitin disc, oxacillin disc and oxacillin agar. Inducible clindamycin resistance was detected usingerythromycin (15μg) and clindamycin (2μg) discs placed 15mm apart on Muller Hinton agar. Of the 160 isolates, 26 (16.3%) were found to be MRSA. Overall prevalence of inducible clindamycin resistance (iMLSB)was 28.8% (46/160), with 22% (30/134) of methicillin-susceptible S. aureus (MSSA) and 61% (16/26) of MRSA exhibiting inducible clindamycin resistance (P=0.0001). Constitutive resistance (cMLSB) was found in 1 (3.7%) of the MRSA isolates and was not detected among MSSA. MSB phenotype was detected in 1 (3.8%) of MRSA isolates and 2 (1.5%) of MSSA. Eight (29.6%) of the MRSA isolates were sensitive to both clindamycin and erythromycin. In conclusion, a high prevalence of inducible clindamycin resistance was observed among S. aureus with significant association between MRSA and inducible clindamycin resistance. It is important that susceptibility test of staphylococci is routinely done to facilitate early detection of clindamycin inducible resistance in the country

Cardiac Surgery: One year experience of cardiac surgery at Muhimbili National Hospital, Dar es Salaam- TANZANIA

Background: Establishing a cardiac unit in developing countries is usually difficult as it is associated with many obstacles of both expertise and financial constraints and more alarming is the mortality rate that may be high. Even after success in the initial stage sustainability of such program is a dilemma. The aim of this study was to determine pattern of disease profile, type of cardiac surgery done and the overall outcome.Methods: All patients who underwent cardiac operation at the centre were prospectively recruited. Patients’ demography and disease characteristics as demonstrated at echocardiography and its confirmation at operation were recorded. Peri-operative factors were the measurable statistics that determined the overall patients’ outcome. All data were entered and analyzed using a spss11.5 window program.Results: A total of 105 cases of cardiac surgery were done 21% were male and 79% were females. Mean age was 19.4±12.3. The majority of cases were due to Rheumatic heart diseases (47.6%), congenital heart disease (35.2%), myxomatous valvular degeneration (16.2%) and pericardial disease 1%. Mitral valve disease was the commonest cause of cardiac disease (58.1%). Prolonged duration of aortic cross-clamp and total operation time were associated with prolonged intensive care stay and poor patients’ outcome respectively (p<0.05). While, ventricular dysfunction and total cardiopulmonary bypass time were not. The overall mortality rate was 13.3%. Majority of all death (64.3%) followed mitral valve repair.Conclusion: The majority of patients (86.7%) who underwent cardiac surgery had full recovery. The mortality of (13.3%) is probably comparable to other settings. The diversity of spectrum of cardiac disease found elsewhere is also found in our community and therefore need to increase community awareness. Mitral valve repair deserve a special entity that requires skills and expertise. The mere presence of suboptimal ventricular dysfunction is probably not a contraindication to cardiac operation. The duration of aortic cross-clamp and total operation time were determinant of postoperative outcome

Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization

One fundamental requirement for quantum computation is to perform universal manipulations of quantum bits at rates much faster than the qubit's rate of decoherence. Recently, fast gate operations have been demonstrated in logical spin qubits composed of two electron spins where the rapid exchange of the two electrons permits electrically controllable rotations around one axis of the qubit. However, universal control of the qubit requires arbitrary rotations around at least two axes. Here we show that by subjecting each electron spin to a magnetic field of different magnitude we achieve full quantum control of the two-electron logical spin qubit with nanosecond operation times. Using a single device, a magnetic field gradient of several hundred milliTesla is generated and sustained using dynamic nuclear polarization of the underlying Ga and As nuclei. Universal control of the two-electron qubit is then demonstrated using quantum state tomography. The presented technique provides the basis for single and potentially multiple qubit operations with gate times that approach the threshold required for quantum error correction.Comment: 11 pages, 4 figures. Supplementary Material included as ancillary fil

From the Kondo Regime to the Mixed-Valence Regime in a Single-Electron Transistor

We demonstrate that the conductance through a single-electron transistor at low temperature is in quantitative agreement with predictions of the equilibrium Anderson model. When an unpaired electron is localized within the transistor, the Kondo effect is observed. Tuning the unpaired electron's energy toward the Fermi level in nearby leads produces a cross-over between the Kondo and mixed-valence regimes of the Anderson model.Comment: 3 pages plus one 2 page postscript file of 5 figures. Submitted to PR

Fano Resonances in Electronic Transport through a Single Electron Transistor

We have observed asymmetric Fano resonances in the conductance of a single electron transistor resulting from interference between a resonant and a nonresonant path through the system. The resonant component shows all the features typical of quantum dots, but the origin of the non-resonant path is unclear. A unique feature of this experimental system, compared to others that show Fano line shapes, is that changing the voltages on various gates allows one to alter the interference between the two paths.Comment: 8 pages, 6 figures. Submitted to PR

Towards identification of a non-abelian state: observation of a quarter of electron charge at ν=5/2\nu=5/2 quantum Hall state

The fractional quantum Hall effect, where plateaus in the Hall resistance at values of coexist with zeros in the longitudinal resistance, results from electron correlations in two dimensions under a strong magnetic field. Current flows along the edges carried by charged excitations (quasi particles) whose charge is a fraction of the electron charge. While earlier research concentrated on odd denominator fractional values of $\nu$, the observation of the even denominator $\nu=5/2$ state sparked a vast interest. This state is conjectured to be characterized by quasiparticles of charge e/4, whose statistics is non-abelian. In other words, interchanging of two quasi particles may modify the state of the system to an orthogonal one, and does not just add a phase as in for fermions or bosons. As such, these quasiparticles may be useful for the construction of a topological quantum computer. Here we report data of shot noise generated by partitioning edge currents in the $\nu=5/2$ state, consistent with the charge of the quasiparticle being e/4, and inconsistent with other potentially possible values, such as e/2 and e. While not proving the non-abelian nature of the $\nu=5/2$ state, this observation is the first step toward a full understanding of these new fractional charges

Empyema in children: a review of fifty-two cases

A clinical study of children suffering from Empyema in one Zimbabwean hospital.A prospective study was undertaken to assess the clinical pattern, management and outcome in children admitted with empyema at Harare Hospital. Fifty-two children were seen and followed up during the three-year period, 1984-1987. All patients were managed with intrapleural drain and antibiotics. Two needed decortication. The predominant pathogen isolated from the pleural cavity was Staphylococus aureus. All survived and on follow up only one child was found to have persistent radiological abnormality and poor exercise tolerance. Early intrapleural drainage and appropriate antibiotics should be the mainstay of treatment for empyema for the majority of children in Zimbabwe