Publications

Niobium carbides and nitrides have been proposed as potential candidates for hardness and related applications, however, comprehensive studies are still needed for better understanding that may pave way for their re-engineering for the ultra hard industry. Here we present ab initio Density Functional Theory calculations that provide a comprehensive description of various hardness characterization parameters. Our results show that NbC in rocksalt (RS) had a higher shear modulus, Young's modulus, and Voigt-Reuss-Hill shear modulus compared to other phases of NbC and NbN considered in this work. Further, it was noted that NbC in RS had a higher value of Vickers hardness amongst the various phases NbC and NbN studied, thus identified as a potential candidate for hardness and related application. Finally, we showed that compounds with Vickers hardness (Hv) > 20 GPa were found to be brittle while those with Hv < 20 GPa were ductile.

OBJECTIVE: To obtain an estimate of the size of, and human immunodeficiency (HIV) prevalence among, young people and children living on the streets of Eldoret, Kenya. METHODS: We counted young people and children using a point-in-time approach, ensuring we reached our target population by engaging relevant community leaders during the planning of the study. We acquired point-in-time count data over a period of 1 week between the hours of 08:00 and 23:00, from both a stationary site and by mobile teams. Participants provided demographic data and a fingerprint (to avoid double-counting) and were encouraged to speak with an HIV counsellor and undergo HIV testing. We used a logistic regression model to test for an association between age or sex and uptake of HIV testing and seropositivity. FINDINGS: Of the 1419 eligible participants counted, 1049 (73.9%) were male with a median age of 18 years. Of the 1029 who spoke with a counsellor, 1004 individuals accepted HIV counselling and 947 agreed to undergo an HIV test. Combining those who were already aware of their HIV-positive status with those who were tested during our study resulted in an overall HIV seroprevalence of 4.1%. The seroprevalence was 2.7% (19/698) for males and 8.9% (23/259) for females. We observed an increase in seroprevalence with increasing age for both sexes, but of much greater magnitude for females. CONCLUSION: By counting young people and children living on the streets and offering them HIV counselling and testing, we could obtain population-based estimates of HIV prevalence.