Optimal power allocation for MIMO-OFDM based Cognitive Radio systems with arbitrary input distributions

In Cognitive Radio (CR) systems, the data rate of the Secondary User (SU) can be maximized by optimizing the transmit power, given a threshold for the interference caused to the Primary User (PU). In conventional power optimization algorithms, the Gaussian input distribution is assumed, which is unrealistic, whereas the Finite Symbol Alphabet (FSA) input distribution, (i.e., M-QAM) is more applicable to practical systems. In this paper, we consider the power optimization problem in multiple input multiple output orthogonal frequency division multiplexing based CR systems given FSA inputs, and derive an optimal power allocation scheme by capitalizing on the relationship between mutual information and minimum mean square error. The proposed scheme is shown to save transmit power compared to its conventional counterpart. Furthermore, our proposed scheme achieves higher data rate compared to the Gaussian optimized power due to fewer number of subcarriers being nulled. The proposed optimal power algorithm is evaluated and compared with the conventional power allocation algorithms using Monte Carlo simulations. Numerical results reveal that, for distances between the SU transmitter and the PU receiver ranging between 50m to 85m, the transmit power saving with the proposed algorithm is in the range 13-90%, whereas the rate gain is in the range 5-31% depending on the modulation scheme (i.e., BPSK, QPSK and 16-QAM) used

Urethral Caruncle with Associated Renoureteric Anomalies

A urethral caruncle is a rare differential diagnosis for a prolapsed mass at the urethral meatus in a prepubertal girl. The aetiopathogenesis of this entity is unclear. We describe the presentation and treatment of a patient with a urethral caruncle and associated renal anomalies that have not been described earlier. The aetiology and treatment of the entity has also been discussed. Keywords: Urethral Caruncle, Premature menarche, Paediatric Bleeding per vagina, Crossed fused ectopi

Uncovering interactions between oral hormone contraceptives and human gut microbiota

The effect of pharmaceuticals, including hormone-based contraceptives, on gut microbiota is both unclear and understudied. Our goal is to evaluate the bidirectional interactions between these drugs and gut microbiota. Specifically, we hypothesize that hormones influence the structure and function of gut microbial communities. Secondly, we predict that microbial community members can metabolize the contraceptive hormones administered in the most common prescriptions. In this study, we use an in vitro culture system exposing gut microbiota to the most common hormones used in hormonal contraceptives. This in-process project will provide information to the research community on the role of gut microbial communities in women relying on orally delivered hormones for contraceptive or health purposes

Prevalence of non-aureus Staphylococcus species causing intramammary infections in Canadian dairy herds

Non-aureus staphylococci (NAS), the microorganisms most frequently isolated from bovine milk worldwide, are a heterogeneous group of numerous species. To establish their importance as a group, the distribution of individual species needs to be determined. In the present study, NAS intramammary infection (IMI) was defined as a milk sample containing ≥1,000 cfu/mL in pure or mixed culture that was obtained from a cohort of cows assembled by the Canadian Bovine Mastitis Research Network. Overall, 6,213 (6.3%) of 98,233 quarter-milk samples from 5,149 cows and 20,305 udder quarters were associated with an NAS IMI. Of the 6,213 phenotypically identified NAS isolates, 5,509 (89%) were stored by the Canadian Bovine Mastitis Research Network Mastitis Pathogen Collection and characterized using partial sequencing of the rpoB housekeeping gene, confirming 5,434 isolates as NAS. Prevalence of each NAS species IMI was estimated using Bayesian models, with presence of a specific NAS species as the outcome. Overall quarter-level NAS IMI prevalence was 26%. The most prevalent species causing IMI were Staphylococcus chromogenes (13%), Staphylococcus simulans (4%), Staphylococcus haemolyticus (3%), Staphylococcus xylosus (2%), and Staphylococcus epidermidis (1%). The prevalence of NAS IMI as a group was highest in first-parity heifers and was evenly distributed throughout cows in parities ≥2. The IMI prevalence of some species such as S. chromogenes, S. simulans, and S. epidermidis differed among parities. Overall prevalence of NAS IMI was 35% at calving, decreased over the next 10 d, and then gradually increased until the end of lactation. The prevalence of S. chromogenes, Staphylococcus gallinarum, Staphylococcus cohnii, and Staphylococcus capitis was highest at calving, whereas the prevalence of S. chromogenes, S. haemolyticus, S. xylosus, and S. cohnii increased during lactation. Although the overall prevalence of NAS IMI was similar across barn types, the prevalence of S. simulans, S. xylosus, S. cohnii, Staphylococcus saprophyticus, S. capitis, and Staphylococcus arlettae IMI was higher in tie-stall barns; the prevalence of S. epidermidis IMI was lowest; and the prevalence of S. chromogenes and Staphylococcus sciuri IMI was highest in bedded-pack barns. Staphylococcus simulans, S. epidermidis, S. xylosus, and S. cohnii IMI were more prevalent in herds with intermediate to high bulk milk somatic cell count (BMSCC) and S. haemolyticus IMI was more prevalent in herds with high BMSCC, whereas other common NAS species IMI were equally prevalent in all 3 BMSCC categories. Distribution of NAS species IMI differed among the 4 regions of Canada. In conclusion, distribution differed considerably among NAS species IMI; therefore, accurate identification (species level) is essential for studying NAS epidemiology

A headspace-gas chromatography method for isopropanol determination in warfarin sodium products as a measure of drug crystallinity

Coumadin® and several generic products of warfarin sodium (WS) contain the crystalline form (clathrate) in which WS and isopropanol (IPA) are associated in a 2:1 molar ratio. IPA is critical in maintaining the WS crystalline structure. Physicochemical properties of the drug and drug product may change when the crystalline drug transforms to amorphous form. A headspace-gas chromatography (HS-GC) method was developed and validated for IPA determination in the WS drug product. n-propanol (NPA) was used as internal standard and the method was validated for specificity, system suitability, linearity, accuracy, precision, range, limits of detection and quantification, and robustness. The method was specific, with good resolution between IPA and NPA peaks. Chromatographic parameters (retention time, IPA/NPA area ratio, tailing factor, theoretical plates, USP symmetry, capacity factor, selectivity and resolution) were consistent over three days of validation. The analytical method was linear from 2–200 µg mL–1 (0.1–10 % IPA present in the drug product). LOD and LOQ were 0.1 and 2 µg mL–1, respectively. Accuracy at low (2 µg mL–1) and high (200 µg mL–1) IPA concentrations of the calibration curve was 103.3–113.3 and 98.9–102.2 % of the nominal value, resp. The validated method was precise, as indicated by the RSD value of less than 2 % at three concentration levels of the calibration curve. The method reported here was utilized to determine accurately and precisely the IPA content in in-house formulations and commercial products. In summary, IPA determination by HS-GC provides an indirect measure of WS crystallinity in the drug product. Nevertheless, it should be confirmed by another analytical method since IPA from the drug substance is not distinguishable from IPA that may be present outside the drug crystals in a dosage form when prepared by wet granulation with IPA

Iatrogenic insertion of impression mould into middle ear and mastoid and its retrieval after 9 years: a case report

The magnitude of hearing loss in Pakistan is enormous. One in twelve children of Pakistan suffers from some form of hearing impairment. Many of them are unable to afford surgical procedures and resort to the use of cheap hearing aids fitted by untrained individuals or people lacking the required expertise. This predisposes the patients to significant complications during a process that is otherwise considered safe. We report the case of a child, where the process of making the mould for a hearing aid led to the perforation of the tympanic membrane and pouring of mould material into the middle ear, necessitating surgical intervention. During initial surgery it was thought that all mould had been removed from the middle ear but 9 years later this child underwent cochlear implantation at the same center and remaining part of ear mould was discovered from mastoid cavity