On machinability of titanium grade 4 under minimum quantity lubrication assisted high speed machining

Abstract: The wonder metal Titanium and its alloys are prime candidate for various automotive, biomedical and aerospace applications due to their good strength-to-weight ratio, biocompatibility and corrosion resistance. Titanium and its alloys are known as difficult-to-machine materials i.e. their machining is challenging. The experimental work reported in the present paper attempts to enhance the machinability of Titanium Grade 4 under the influence of minimum quantity lubrication at high speed conditions. In this work a total of twenty seven experiments has been conducted based on full factorial design of experiment technique. Cutting speed, feed rate, and depth of cut are varied at three levels each and the values of important MQL parameters are fixed. The effects of machining parameters on surface roughness are discussed. Machining at optimum combination of parameters resulted in precision finish with maximum roughness value 2.16 μm and maximum tool flank wear value 0.201 mm. The research results reveal the superiority of MQL over conventional wet cooling to successfully machine Titanium Grade 4 at high speed conditions with sustainability

Tracking mortality in near to real time provides essential information about the impact of the COVID-19 pandemic in South Africa in 2020

Background. Producing timely and accurate estimates of the impact of COVID-19 on mortality is challenging for most countries, but impossible for South Africa (SA) from cause-of-death statistics. Objectives. To quantify the excess deaths and likely magnitude of COVID-19 in SA in 2020 and draw conclusions on monitoring the epidemic in 2021. Methods. Basic details of deaths registered on the National Population Register by the Department of Home Affairs (DoHA) are provided to the South African Medical Research Council weekly. Adjustments are made to the numbers of weekly deaths to account for non-registration on the population register, as well as late registration of death with the DoHA. The weekly number of deaths is compared with the number predicted based on the Holt-Winters time-series analysis of past deaths for provinces and metropolitan areas. Excess deaths were calculated for all-causes deaths and natural deaths, using the predicted deaths as a baseline. In addition, an adjustment was made to the baseline for natural deaths to account for the drop in natural deaths due to lockdown. Results. We estimated that just over 550 000 deaths occurred among persons aged ≥1 year during 2020, 13% higher than the 485 000 predicted before the pandemic. A pronounced increase in weekly deaths from natural causes peaked in the middle of July across all ages except <20 years, and across all provinces with slightly different timing. During December, it became clear that SA was experiencing a second wave of COVID-19 that would exceed the death toll of the first wave. In 2020, there were 70 000 - 76 000 excess deaths from natural causes, depending on the base. Using the adjusted base, the excess death rate from natural causes was 122 per 100 000 population, with a male-to-female ratio of 0.78. Deaths from unnatural causes halved for both males and females during the stringent lockdown level 5. The numbers reverted towards the predicted number with some fluctuations as lockdown restrictions varied. Just under 5 000 unnatural deaths were averted. Conclusions. Tracking the weekly numbers of deaths in near to real time has provided important information about the spatiotemporal impact of the pandemic and highlights that the ~28 000 reported COVID-19 deaths during 2020 substantially understate the death toll from COVID-19. There is an urgent need to re-engineer the system of collecting and processing cause-of-death information so that it can be accessed in a timely way to inform public health actions

Risk factors for the development of osteoporosis in a South African population: A prospective analysis

Despite the vast number of risk factors that apparently predispose to the development ofosteoporosis (OP), they have not been accurately identified and given relative priority. In order to analyse possible risk factors prospectively in a local patient population with overt OP (histomorphometrically confirmed and characterised) and compare it with an appropriately matched non-OP control group (with normal bone mass on dualenergy X-ray absorptiometry), a detailed general history, risk factor analysis, dietary history and anthropometric data were obtained from 56 OP and 125 non-OP subjects. In females a positive family history of OP (P =0,002), a fair complexion (P =0,009), lower body mass (P =0,02) and height (P =0,03), no breast-feeding of babies (P =0,006), a history of smoking (P =0,001) and fat distribution around the waist (P =0,009) were identified as risk factors. In males lack of exercise (P =0,008), a history of smoking (P =0,01), lower body mass (P = 0,04) and height (P = 0,04), a preference for salty food (P =0,02) and fat distribution around the waist (P =0,002) appeared to predispose. Dietary calcium, phosphorus, protein and caffeine intakes were similar in OP and control subjects, but alcohol consumption was clearly higher in both OP males (P = 0,001) and females (P = 0,01)

Issues in public health: Unnatural deaths, alcohol bans and curfews: Evidence from a quasi-natural experiment during COVID-19

Background. Coronavirus disease-19 (COVID-19) restrictions, particularly relating to the sale of alcohol and hours of curfew, have had a marked effect on the temporal pattern of unnatural deaths in South Africa. Methods. Death data were collected over 68 weeks from January 2020 to April 2021, together with information on the nature of restrictions (if any) on the sale of alcohol, and hours of curfew. Data were analysed using a simple ordinary least square (OLS) regression model to estimate the relative contribution of restrictions on the sale of alcohol and hours of curfew to the pattern of excess unnatural deaths. Results. The complete restriction on the sale of alcohol resulted in a statistically significant reduction in unnatural deaths regardless of the length of curfew. To the contrary, periods where no or limited restrictions on alcohol were in force had no significant effect, or resulted in significantly increased unnatural deaths. Conclusion. The present study highlights an association between alcohol availability and the number of unnatural deaths and demonstrates the extent to which those deaths might be averted by disrupting the alcohol supply. While this is not a long-term solution to addressing alcohol-related harm, it further raises the importance of implementing evidence-based alcohol control measures

Nearly Complete Genome Sequence of a Novel Phlebovirus-Like Virus Detected in a Human Plasma Sample by High-Throughput Sequencing.

Here, we report a novel phlebovirus-like virus sequence detected in a plasma sample from a febrile adult patient collected in the United Republic of Tanzania in 2014. A nearly complete RNA sequence was generated by high-throughput sequencing on a HiSeq 2500 instrument and further confirmed after repeating the analysis, starting from the initial sample

Virosaurus A Reference to Explore and Capture Virus Genetic Diversity.

The huge genetic diversity of circulating viruses is a challenge for diagnostic assays for emerging or rare viral diseases. High-throughput technology offers a new opportunity to explore the global virome of patients without preconception about the culpable pathogens. It requires a solid reference dataset to be accurate. Virosaurus has been designed to offer a non-biased, automatized and annotated database for clinical metagenomics studies and diagnosis. Raw viral sequences have been extracted from GenBank, and cleaned up to remove potentially erroneous sequences. Complete sequences have been identified for all genera infecting vertebrates, plants and other eukaryotes (insect, fungus, etc.). To facilitate the analysis of clinically relevant viruses, we have annotated all sequences with official and common virus names, acronym, genotypes, and genomic features (linear, circular, DNA, RNA, etc.). Sequences have been clustered to remove redundancy at 90% or 98% identity. The analysis of clustering results reveals the state of the virus genetic landscape knowledge. Because herpes and poxviruses were under-represented in complete genomes considering their potential diversity in nature, we used genes instead of complete genomes for those in Virosaurus

Drastic reduction of orthopaedic services at an urban tertiary hospital in South Africa during COVID-19: Lessons for the future response to the pandemic

Background. The COVID-19 pandemic has impacted on the global surgery landscape.Objectives. To analyse and describe the initial impact of the COVID-19 pandemic on orthopaedic surgery at Groote Schuur Hospital, a tertiary academic hospital in South Africa.Methods. The number of orthopaedic surgical cases, emergency theatre patient waiting times, and numbers of outpatient clinic visits, ward admissions, bed occupancies and total inpatient days for January - April 2019 (pre-COVID-19) were compared with the same time frame in 2020 (COVID-19). The COVID-19 timeframe included initiation of a national ‘hard lockdown’ from 26 March 2020, in preparation for an increasing volume of COVID-19 cases.Results. April 2020, the time of the imposed hard lockdown, was the most affected month, although the number of surgical cases had started to decrease slowly during the 3 preceding months. The total number of surgeries, outpatient visits and ward admissions decreased significantly during April 2020 (55.2%, 69.1% and 60.6%, respectively) compared with April 2019 (p<0.05). Trauma cases were reduced by 40% in April 2020. Overall emergency theatre patient waiting time was 30% lower for April 2020 compared with 2019.Conclusions. COVID-19 and the associated lockdown has heavily impacted on both orthopaedic inpatient and outpatient services. Lockdown led to a larger reduction in the orthopaedic trauma burden than in international centres, but the overall reduction in surgeries, outpatient visits and hospital admissions was less. This lesser reduction was probably due to local factors, but also to a conscious decision to avoid total collapse of our surgical services

Low 30-day mortality in South African orthopaedic patients undergoing surgery at an academic hospital during the first wave of the COVID-19 pandemic: It was safe to perform orthopaedic procedures at our hospital during the first COVID-19 peak

Background. Initial local and global evidence suggests that SARS-CoV-2-infected patients who undergo surgery, and those who become infected perioperatively, have an increased mortality risk post surgery.Objectives. To analyse and describe the 30-day mortality, presurgical COVID-19 status and hospital-acquired SARS-CoV-2 infection rates of patients, both SARS-CoV-2-positive and negative, undergoing orthopaedic surgery at a tertiary academic hospital in South Africa (SA) during the first COVID-19 peak.Methods. This single-centre, observational, prospective study included patients who underwent orthopaedic procedures from 1 April 2020 (beginning of the COVID-19 case increase in SA) to 31 July 2020 (first COVID-19 peak in SA). All patients were screened for COVID-19 and were confirmed positive if they had a positive laboratory quantitative polymerase chain reaction test for SARS-CoV-2 RNA on a nasopharyngeal or oral swab. Thirty-day mortality, presurgical COVID-19 status and hospital-acquired SARS-CoV-2 infection were assessed.Results. Overall, a total of 433 operations were performed on 346 patients during the timeframe. Of these patients, 65.9% (n=228) were male and 34.1% (n=118) were female. The mean (standard deviation) age was 42.5 (16.8) years (range 9 - 89). Of the patients, 5 (1.4%) were identified as COVID-19 patients under investigation (PUI) on admission and tested positive for SARS-CoV-2 before surgery, and 1 (0.3%) contracted SARS-CoV-2 perioperatively; all survived 30 days post surgery. Twenty-nine patients were lost to follow-up, and data were missing for 6 patients. The final analysis was performed excluding these 35 patients. Of the 311 patients included in the final 30-day mortality analysis, 303 (97%) had a follow-up observation ≥30 days after the operation. The overall 30-day mortality for these patients was 2.5% (n=8 deaths). None of the recorded deaths were of screened COVID-19 PUI.Conclusions. We report a low 30-day mortality rate of 2.5% (n=8) for patients undergoing orthopaedic surgery at our hospital during the first COVID-19 peak. None of the deaths were COVID-19 related, and all patients who tested SARS-CoV-2-positive, before or after surgery, survived. Our overall 30-day mortality rate correlates with several other reports of orthopaedic centres analysing over similar timeframes during the first peak of the COVID-19 pandemic. Regarding mortality and SARS-CoV-2 infection risk, we can conclude that with the appropriate measures taken, it was safe to undergo orthopaedic procedures at our hospital during the first peak of the COVID-19 pandemic in SA