Venous thromboembolism risk and prophylaxis prescription in surgical patients at a tertiary hospital in Eastern Cape Province, South Africa

Background. Venous thromboembolism (VTE) is a common complication during and after hospitalisation, and is regarded as the most common cause of preventable death in hospitalised patients worldwide. Despite its importance, there are few data on VTE risk and adherence to prophylaxis prescription guidelines in surgical patients from the South African (SA) public sector, especially from lowresource environments such as Eastern Cape Province.Objectives. To evaluate the risk and prescription of VTE prophylaxis to surgical patients at a tertiary government hospital in the Eastern Cape.Methods. A cross-sectional clinical audit of general surgical inpatients was performed on two dates during July and August 2017. Patients’ VTE risk was calculated by using the Caprini risk assessment model (RAM) and thromboprophylaxis prescription evaluated accordingly.Results. A total of 179 patients were included in the study, of whom 56% were male and 44% female. The average age was 45 (range 18 - 83) years. Of the total number of participants, 33% were elective cases and 67% were emergency admissions. With application of RAM, 77% of patients were at risk of VTE (Caprini score ≥2), with 81% of elective and 74% of emergency patients being at risk. The most prevalent risk factors for VTE were major surgery (34%), age 41 - 60 years (30%), age 61 - 74 years (20%) and sepsis during the previous month (27%). A contraindication to chemoprophylaxis was recorded in 30% of patients, with the most prevalent being renal dysfunction (40%), peptic ulcer disease (34%), active bleeding (17%), liver dysfunction (17%), coagulopathy (6%) and recent cerebral haemorrhage (6%). With regard to VTE risk profile and contraindications to chemoprophylaxis, the correct thromboprophylactic treatment was prescribed to 26% of at-risk patients, with 21% of elective and 27% of emergency admission patients receiving the correct therapy.Conclusions. Despite a high proportion of patients being at risk of VTE, the rate of adequate thromboprophylaxis prescription for surgical inpatients at Frere Hospital, East London, SA is very low. Increased availability of mechanical prophylaxis, as well as interventions to improve the rate of adequate prophylaxis prescription, needs to be evaluated for feasibility and effect in this hospital and other SA public hospitals

Scattering of cosmic strings by black holes: loop formation

We study the deformation of a long cosmic string by a nearby rotating black hole. We examine whether the deformation of a cosmic string, induced by the gravitational field of a Kerr black hole, may lead to the formation of a loop of cosmic string. The segment of the string which enters the ergosphere of a rotating black hole gets deformed and, if it is sufficiently twisted, it can self-intersect chopping off a loop of cosmic string. We find that the formation of a loop, via this mechanism, is a rare event. It will only arise in a small region of the collision phase space, which depends on the string velocity, the impact parameter and the black hole angular momentum. We conclude that generically, the cosmic string is simply scattered or captured by the rotating black hole.Comment: 11 pages, 2 figures, RevTe

Venous thromboembolism risk and prophylaxis prescription in surgical patients at a tertiary hospital in Eastern Cape Province, South Africa

Background. Venous thromboembolism (VTE) is a common complication during and after hospitalisation, and is regarded as the most common cause of preventable death in hospitalised patients worldwide. Despite its importance, there are few data on VTE risk and adherence to prophylaxis prescription guidelines in surgical patients from the South African (SA) public sector, especially from low-resource environments such as Eastern Cape Province.Objectives. To evaluate the risk and prescription of VTE prophylaxis to surgical patients at a tertiary government hospital in the Eastern Cape.Methods. A cross-sectional clinical audit of general surgical inpatients was performed on two dates during July and August 2017. Patients’ VTE risk was calculated by using the Caprini risk assessment model (RAM) and thromboprophylaxis prescription evaluated accordingly.Results. A total of 179 patients were included in the study, of whom 56% were male and 44% female. The average age was 45 (range 18 - 83) years. Of the total number of participants, 33% were elective cases and 67% were emergency admissions. With application of RAM, 77% of patients were at risk of VTE (Caprini score ≥2), with 81% of elective and 74% of emergency patients being at risk. The most prevalent risk factors for VTE were major surgery (34%), age 41 - 60 years (30%), age 61 - 74 years (20%) and sepsis during the previous month (27%). A contraindication to chemoprophylaxis was recorded in 30% of patients, with the most prevalent being renal dysfunction (40%), peptic ulcer disease (34%), active bleeding (17%), liver dysfunction (17%), coagulopathy (6%) and recent cerebral haemorrhage (6%). With regard to VTE risk profile and contraindications to chemoprophylaxis, the correct thromboprophylactic treatment was prescribed to 26% of at-risk patients, with 21% of elective and 27% of emergency admission patients receiving the correct therapy.Conclusions. Despite a high proportion of patients being at risk of VTE, the rate of adequate thromboprophylaxis prescription for surgical inpatients at Frere Hospital, East London, SA is very low. Increased availability of mechanical prophylaxis, as well as interventions to improve the rate of adequate prophylaxis prescription, needs to be evaluated for feasibility and effect in this hospital and other SA public hospitals

Cosmic strings and Natural Inflation

In the present work we discuss cosmic strings in natural inflation. Our analysis is based entirely on the CMB quadrupole temperature anisotropy and on the existing upper bound on the cosmic string tension. Our results show that the allowed range for both parameters of the inflationary model is very different from the range obtained recently if cosmic strings are formed at the same time with inflation, while if strings are formed after inflation we find that the parameters of the inflationary model are similar to the ones obtained recently.Comment: 12 pages, 0 tables, 4 figures, accepted for publication in JHE

Constraints on Supersymmetric Grand Unified Theories from Cosmology

Within the context of SUSY GUTs, cosmic strings are generically formed at the end of hybrid inflation. However, the WMAP CMB measurements strongly constrain the possible cosmic strings contribution to the angular power spectrum of anisotropies. We investigate the parameter space of SUSY hybrid (F- and D- term) inflation, to get the conditions under which theoretical predictions are in agreement with data. The predictions of F-term inflation are in agreement with data, only if the superpotential coupling $\kappa$ is small. In particular, for SUSY SO(10), the upper bound is \kappa\lsim 7\times 10^{-7}. This fine tuning problem can be lifted if we employ the curvaton mechanism, in which case \kappa\lsim 8\times 10^{-3}; higher values are not allowed by the gravitino constraint. The constraint on $\kappa$ is equivalent to a constraint on the SSB mass scale $M$, namely M \lsim 2\times 10^{15} GeV. The study of D-term inflation shows that the inflaton field is of the order of the Planck scale; one should therefore consider SUGRA. We find that the cosmic strings contribution to the CMB anisotropies is not constant, but it is strongly dependent on the gauge coupling $g$ and on the superpotential coupling $\lambda$. We obtain g\lsim 2\times 10^{-2} and \lambda \lsim 3\times 10^{-5}. SUGRA corrections induce also a lower limit for $\lambda$. Equivalently, the Fayet-Iliopoulos term $\xi$ must satisfy \sqrt\xi \lsim 2\times 10^{15} GeV. This constraint holds for all allowed values of $g$.Comment: 32 pages, 7 figures. To match published versio

Driving Under the Influence of Drugs: A Single Parallel Monitoring-Based Quantification Approach on Whole Blood.

Driving under the influence of psychoactive substances is a major cause of motor vehicle crashes. The identification and quantification of substances most frequently involved in impaired-driving cases in a single analytic procedure could be an important asset in forensic toxicology. In this study, a highly sensitive and selective liquid chromatography (LC) approach hyphenated with Orbitrap high-resolution mass spectrometry (HRMS) was developed for the quantification of the main drugs present in the context of driving under the influence of drugs (DUID) using 100 μL of whole blood. This procedure involves a simple sample preparation and benefit from the selectivity brought by parallel reaction monitoring (PRM) allowing to solve most DUID cases using a single multi-analyte injection. The method was fully validated for the quantification of the major classes of psychoactive substances associated with impaired-driving (cannabinoids, cocaine and its metabolites, amphetamines, opiates and opioids, and the major benzodiazepines and z-drugs). The validation guidelines set by the "Société Française des Sciences et des Techniques Pharmaceutiques" (SFSTP) were respected for 22 psychoactive substances using 15 internal standards. Trueness was measured to be between 95.3 and 107.6% for all the tested concentrations. Precision represented by repeatability and intermediate precision was lower than 12% while recovery (RE) and matrix effect (ME) ranged from 49 to 105% and from -51 to 3%, respectively. The validated procedure provides an efficient approach for the simultaneous and simple quantification of the major drugs associated with impaired driving benefiting from the selectivity of PRM

Hybrid inflation followed by modular inflation

Inflationary models with a superheavy scale F-term hybrid inflation followed by an intermediate scale modular inflation are considered. The restrictions on the power spectrum P_R of curvature perturbation and the spectral index n_s from the recent data within the power-law cosmological model with cold dark matter and a cosmological constant can be met provided that the number of e-foldings N_HI* suffered by the pivot scale k_*=0.002/Mpc during hybrid inflation is suitably restricted. The additional e-foldings needed for solving the horizon and flatness problems are generated by modular inflation with a string axion as inflaton. For central values of P_R and n_s, the grand unification scale comes out, in the case of standard hybrid inflation, close to its supersymmetric value M_GUT=2.86 x 10^16 GeV, the relevant coupling constant is relatively large (0.005-0.14), and N_HI* is between 10 and 21.7. In the shifted [smooth] hybrid inflation case, the grand unification scale can be identified with M_GUT for N_HI*=21 [N_HI*=18].Comment: 13 pages including 3 figures, uses ws-ijmpa.cls, minor corrections included, talk given at the CTP Symposium on Supersymmetry at LHC: Theoretical and Experimental Perspectives, British University in Egypt (BUE), Cairo, 11-14 March 2007 (to appear in the proceedings

Production of topological defects at the end of inflation

Hybrid inflation within supersymmetric grand unified theories, as well as inflation through brane collisions within braneworld cosmological models, lead to the formation of one-dimensional defects. Observational data, mainly from the cosmic microwave background temperature anisotropies but also from the gravitational wave background, impose constraints on the free parameters of the models. I review these inflationary models and discuss the constraints from the currently available data.Comment: 9 pages, Invited talk in the Conference "Challenges in Particle Astrophysics" -- 6th Rencontres du Vietnam, Hanoi (Vietnam) 6-12 Aug. 200

A Note on the evolution of cosmic string/superstring networks

In the context of brane world scenario, cosmic superstrings can be formed in D-brane annihilation at the end of the brane inflationary era. The cosmic superstring network has a scaling solution and the characteristic scale of the network is proportional to the square root of the reconnection probability.Comment: 13 pages, 12 figures (revised version