Diagnostic issues in abdominal tuberculosis

Objective: To analyze the modes of presentation and diagnostic issues in the management of abdominal tuberculosis at a tertiary care hospital in a developing country, where most of the established diagnostic modalities are available.SETTING: The Aga Khan University Hospital, Karachi.Methods: This study is a retrospective review of medical records of all inpatients, diagnosed to have abdominal tuberculosis, from January 1991 to December 1997. The data was collected and particularly analyzed for spectrum of presentation and role of various diagnostic modalities. Of special interest was the sub-group of patients, who after all investigations did not have a firm diagnosis. Following a literature review recommendations have been developed for empiric antituberculous therapy in such patients.Results: A total of 135 patients were diagnosed to have abdominal tuberculosis with a mean age of 34 years and a male to female ratio of 1:2. Ninety-six (71%) patients presented with chronic abdominal symptoms, while 39 (29%) presented as an acute surgical emergency mandating exploratory laparotomy. A tissue-based diagnosis was established in 95 (70.30%) patients, while radiological diagnosis was made in 30 (22.2%) patients. In 10 (7.4%) patients all investigations undertaken could not reveal a final diagnosis; these were treated empirically on the basis of a strong clinical suspicion.CONCLUSION: The diagnosis of abdominal tuberculosis can be made confidently in most of the cases. There may be a small group of patients where diagnosis cannot be made despite appropriate investigations and a therapeutic trial of ATT may be considered with close monitoring according to a pre-fixed protocol

Cardiovascular outcomes of type 2 diabetic patients treated with DPP‑4 inhibitors versus sulphonylureas as add-on to metformin in clinical practice

DPP-4 inhibitors (DPP-4i) and sulphonylureas remain the most widely prescribed add-on treatments after metformin. However, there is limited evidence from clinical practice comparing major adverse cardiovascular events (MACE) in patients prescribed these treatments, particularly among those without prior history of MACE and from vulnerable population groups. Using electronic health records from UK primary care, we undertook a retrospective cohort study with people diagnosed type-2 diabetes mellitus, comparing incidence of MACE (myocardial infarction, stroke, major cardiovascular surgery, unstable angina) and all-cause mortality among those prescribed DPP-4i versus sulphonylureas as add-on to metformin. We stratified analysis by history of MACE, age, social deprivation and comorbidities and adjusted for HbA1c, weight, smoking-status, comorbidities and medications. We identified 17,570 patients prescribed sulphonylureas and 6,267 prescribed DPP-4i between 2008–2017. Of these, 16.3% had pre-existing MACE. Primary incidence of MACE was similar in patients prescribed DPP-4i and sulphonylureas (10.3 vs 8.5 events per 1000 person-years; adjusted Hazard Ratio (adjHR): 0.94; 95%CI 0.80–1.14). For those with pre-existing MACE, rates for recurrence were higher overall, but similar between the two groups (21.8 vs 17.2 events per 1000 person-years; adjHR: 0.93; 95%CI 0.69–1.24). For those aged over 75 and with BMI less than 25 kg/m2 there was a protective effect for DPP-I, warranting further investigation. Patients initiating a DPP-4i had similar risk of cardiovascular outcomes to those initiating a sulphonylurea. This indicates the choice should be based on safety and cost, not cardiovascular prognosis, when deciding between a DPP-4i or sulphonylurea as add-on to metformin

Mn induced modifications of Ga 3d photoemission from (Ga, Mn)As: evidence for long range effects

Using synchrotron based photoemission, we have investigated the Mn-induced changes in Ga 3d core level spectra from as-grown ${\rm Ga}_{1-x}{\rm Mn}_{x}{\rm As}$. Although Mn is located in Ga substitutional sites, and does therefore not have any Ga nearest neighbours, the impact of Mn on the Ga core level spectra is pronounced even at Mn concentrations in the range of 0.5%. The analysis shows that each Mn atom affects a volume corresponding to a sphere with around 1.4 nm diameter.Comment: Submitted to Physical Review B, Brief Repor

Non-uniqueness of the Dirac theory in a curved spacetime

We summarize a recent work on the subject title. The Dirac equation in a curved spacetime depends on a field of coefficients (essentially the Dirac matrices), for which a continuum of different choices are possible. We study the conditions under which a change of the coefficient fields leads to an equivalent Hamiltonian operator H, or to an equivalent energy operator E. In this paper, we focus on the standard version of the gravitational Dirac equation, but the non-uniqueness applies also to our alternative versions. We find that the changes which lead to an equivalent operator H, or respectively to an equivalent operator E, are determined by initial data, or respectively have to make some point-dependent antihermitian matrix vanish. Thus, the vast majority of the possible coefficient changes lead neither to an equivalent operator H, nor to an equivalent operator E, whence a lack of uniqueness. We show that even the Dirac energy spectrum is not unique.Comment: 13 pages (standard 12pt article format). Text of a talk given at the 1st Mediterranean Conference on Classical and Quantum Gravity, Kolymbari (Greece), Sept. 14-18, 200

Magnetization hysteresis and time decay measurements in FeSe0.50_{0.50}Te0.50_{0.50} : Evidence for fluctuation in mean free path induced pinning

We present results of magnetic measurements relating to vortex phase diagram in a single crystal of FeSe$_{0.5}$Te$_{0.5}$ which displays second magnetization peak anomaly for $H \parallel c$. The possible role of the crystalline anisotropy on vortex pinning is explored via magnetic torque magnetometry. We present evidence in favor of pinning related to spatial variations of the charge carrier mean free path leading to small bundle vortex pinning by randomly distributed (weak) pinning centers for both $H \parallel c$ and $H \perp c$. This is further corroborated using magnetization data for $H \parallel c$ in a single crystal of FeSe$_{0.35}$Te$_{0.65}$. Dynamical response across second magnetization peak (SMP) anomaly in FeSe$_{0.5}$Te$_{0.5}$ has been compared with that across the well researched phenomenon of peak effect (PE) in a single crystal of CeRu$_2$.Comment: 11 figures, provided additional data in another sample, added Fig.

Quantum Discord in the Ground and Thermal States of Spin Clusters

Quantum discord is a general measure of bipartite quantum correlations with a potential role in quantum information processing tasks. Spin clusters serve as ideal candidates for the implementation of some of the associated protocols. In this paper, we consider a symmetric spin trimer and a tetramer, which describe a number of known molecular magnets, and compute the quantum discord in the ground and thermal states of the clusters. The variations of the quantum discord as a function of anisotropy parameter, magnetic field and temperature are investigated. We obtain a number of interesting results such as a finite value of the quantum discord in the trimer ground state for which the pairwise entanglement is known to be zero, differences in the nature of some of the variations in the ferromagnetic and antiferromagnetic cases and discontinuous jumps in the magnitude of the quantum discord at first order quantum phase transition points. A remarkable feature that is observed is that the quantum discord completely vanishes only in the asymptotic limit of temperature $T\rightarrow\infty$. We further study the dynamics of the quantum discord and the pairwise entanglement at T=0 under the effect of a dephasing channel describing the interaction of the reduced spin cluster state with independent local environments. The QD is found to vanish asymptotically as $t\rightarrow\infty$. In the case of the spin trimer, the pairwise entanglement has a zero value at all times and reaches a zero value in a finite time in the case of the tetramer.Comment: Article, 16 pages, 9 figure