An Enhanced Software Quality Testing Approach Using Metamorphic Testing Technique

The software testing process plays an important role in improving the quality of the software product. The product or program which is free from errors greatly contributes to assuring the quality of the software. An oracle in software testing is a person (tester) who performs the testing process. The oracle problem is the difficulty of determining the expected outcomes of selected test cases. A tester (oracle) may not always be available, or might be available but the process is too expensive and difficult to apply. The research presented in this paper proposes an approach for reducing the effect of the oracle problem during testing software and hence enhancing the quality of testing. Metamorphic Testing (MT) approach has been introduced and applied to generate a follow-up test case for multiple executions of program under test and verify the result automatically.  An experimental method has been used to explain the mechanism of work for (MT). JUNIT tool which supports MT has been used to apply selected case studies (trigonometric function, geometric shapes classification, booking web service). The obtained results showed a good enhancement in the testing process. The importance of this research lies in overcoming oracle problem or alleviates it and thus, the research contributes to knowledge the domain by guiding researchers to use the metamorphic method because of its great advantages, as well as evaluating the effect of metamorphic method through empirical studies

Antimicrobial Activity of Terpenoids Extracted from Annona muricata Seeds and its Endophytic Aspergillus niger Strain SH3 Either Singly or in Combination

BACKGROUND: Annona muricata (Soursop) has an antimicrobial activity toward various pathogenic microorganisms which support its ethnomedicinal for the treatment of many infectious diseases. AIM: Aim of the present study to evaluate the relation between antimicrobial activities of terpenoids extracted from different soursop parts with the isolated endophytic fungi. METHODS: Endophytic fungal species of pulp and peel of Annona fruit along with those of seeds were isolated. Salkowski test was used for qualitative screening of terpenoids in plant and the isolated endophytic Aspergillus niger strain SH3. RESULTS: Endophytic A. niger strain SH3 and Annona seed extract showed high terpenoid content indicated by the high intensity of reddish-brown colour. GC/Mass analysis revealed six compounds of terpenoids from endophytic A. niger strain SH3 extract and four compounds from seed extract with different retention times. The antimicrobial assay was performed using A. niger strain SH3 extract and Annona seed extract singly or in combinations against S. aureus, P. aeruginosa, E. coli and C. albicans. CONCLUSION: The results revealed the significant antimicrobial activity of both extracts. However, the combined extract showed some reduction in antimicrobial activity which could be attributed to the antagonistic effect exhibited by their constituents

Effect of Occupational Cadmium Exposure on Parathyroid Gland

BACKGROUND: Cadmium (Cd) is used in many industries. High-level exposure is associated with severe kidney and bone damage.AIM: This study investigates the possible effect of occupational cadmium exposure on parathyroid gland and some minerals in workers.METHODS: Environmental air monitoring of cadmium was done. Serum and urine cadmium levels, kidney function, some minerals, and plasma parathormone were estimated in the studied groups. RESULTS: The exposed workers had significantly higher Cd concentration in serum and urine than controls. The mean levels of plasma parathyroid hormone, serum phosphorus and magnesium were significantly lower among the exposed group. However, the mean levels of serum creatinine and calcium were significantly higher in the same group when compared to referents. There was a significant positive correlation between Cd concentration in the serum and urine for the exposed group. The biological Cd exposure indices correlated positively with serum calcium and negatively with plasma PTH level. The prevalence of musculoskeletal complaints, bone ache, joint pain and muscle spasm were more prevalent among the exposed workers compared with the controls with odds ratio 4.316, 3.053 and 3.103 respectively.CONCLUSIONS: Occupational cadmium exposure has an adverse effect on PTH level and serum human minerals

Effects of the Switching Frequency of Random Modulated Power Converter on the G3 Power Line Communication System

Power Line Communication (PLC) technologies utilize existing power cables for both power and data transmission which minimizes cost and complexity. However, recent studies show that alternative modulation schemes such as Random Pulse Width Modulation (RPWM), applied to power converter to minimize conducted emissions, have possible side effects on the PLC system. In this work, the effects of the switching frequency of randomly modulated power converter on the G3-PLC system is investigated. To this end, a range of switching frequencies from 10 kHz-100 kHz is applied to a randomly modulated DC-DC converter and its potential effect on the G3-PLC is studied. Experimental results confirmed that switching frequencies near the bandwidth of the G3-PLC caused significant disturbance and possible coexistence issue compared to the frequencies out of this range. Moreover, there is a tradeoff between Electromagnetic Interference (EMI) reduction and coexistence issue that is Random Frequency Modulation, which is very effective for EMI reduction, is found to be very disruptive for G3-PLC, compared to alternative random modulation techniques like Random Pulse Position Modulation

Emergence of Undetectable Malaria Parasites: A Threat under the Radar amid the COVID-19 Pandemic?

Rapid diagnostic tests (RDTs) play a critical role in malaria diagnosis and control. The emergence of Plasmodium falciparum parasites that can evade detection by RDTs threatens control and elimination efforts. These parasites lack or have altered genes encoding histidine-rich proteins (HRPs) 2 and 3, the antigens recognized by HRP2-based RDTs. Surveillance of such parasites is dependent on identifying false-negative RDT results among suspected malaria cases, a task made more challenging during the current pandemic because of the overlap of symptoms between malaria and COVID-19, particularly in areas of low malaria transmission. Here, we share our perspective on the emergence of P. falciparum parasites lacking HRP2 and HRP3, and the surveillance needed to identify them amid the COVID-19 pandemic

The usefulness of rapid diagnostic tests in the new context of low malaria transmission in zanzibar.

BACKGROUND\ud \ud We assessed if histidine-rich-protein-2 (HRP2) based rapid diagnostic test (RDT) remains an efficient tool for Plasmodium falciparum case detection among fever patients in Zanzibar and if primary health care workers continue to adhere to RDT results in the new epidemiological context of low malaria transmission. Further, we evaluated the performance of RDT within the newly adopted integrated management of childhood illness (IMCI) algorithm in Zanzibar.\ud \ud METHODS AND FINDINGS\ud \ud We enrolled 3890 patients aged ≥2 months with uncomplicated febrile illness in this health facility based observational study conducted in 12 primary health care facilities in Zanzibar, between May-July 2010. One patient had an inconclusive RDT result. Overall 121/3889 (3.1%) patients were RDT positive. The highest RDT positivity rate, 32/528 (6.1%), was found in children aged 5-14 years. RDT sensitivity and specificity against PCR was 76.5% (95% CI 69.0-83.9%) and 99.9% (95% CI 99.7-100%), and against blood smear microscopy 78.6% (95% CI 70.8-85.1%) and 99.7% (95% CI 99.6-99.9%), respectively. All RDT positive, but only 3/3768 RDT negative patients received anti-malarial treatment. Adherence to RDT results was thus 3887/3889 (99.9%). RDT performed well in the IMCI algorithm with equally high adherence among children <5 years as compared with other age groups.\ud \ud CONCLUSIONS\ud \ud The sensitivity of HRP-2 based RDT in the hands of health care workers compared with both PCR and microscopy for P. falciparum case detection was relatively low, whereas adherence to test results with anti-malarial treatment was excellent. Moreover, the results provide evidence that RDT can be reliably integrated in IMCI as a tool for improved childhood fever management. However, the relatively low RDT sensitivity highlights the need for improved quality control of RDT use in primary health care facilities, but also for more sensitive point-of-care malaria diagnostic tools in the new epidemiological context of low malaria transmission in Zanzibar.\ud \ud TRIAL REGISTRATION\ud \ud ClinicalTrials.gov NCT01002066

Snapshot PCR surveillance for SARS-CoV-2 in hospital staff in England

Background: Significant nosocomial transmission of SARS-CoV-2 has been demonstrated. Understanding the prevalence of SARS-CoV-2 carriage amongst HCWs at work is necessary to inform the development of HCW screening programmes to control nosocomial spread. / Methods: Cross-sectional ‘snapshot’ survey from April-May 2020; HCWs recruited from six UK hospitals. Participants self-completed a health questionnaire and underwent a combined viral nose and throat swab, tested by Polymerase Chain Reaction (PCR) for SARS-CoV-2 with viral culture on majority of positive samples. / Findings: Point prevalence of SARS-CoV-2 carriage across the sites was 2.0% (23/1152 participants), median cycle threshold value 35.70 (IQR:32.42–37.57). 17 were previously symptomatic, two currently symptomatic (isolated anosmia and sore throat); the remainder declared no prior or current symptoms. Symptoms in the past month were associated with threefold increased odds of testing positive (aOR 3.46, 95%CI 1.38–8.67; p = 0.008). SARS-CoV-2 virus was isolated from only one (5%) of nineteen cultured samples. A large proportion (39%) of participants reported symptoms in the past month. / Interpretation: The point-prevalence is similar to previous estimates for HCWs in April 2020, though a magnitude higher than in the general population. Based upon interpretation of symptom history and testing results including viral culture, the majority of those testing positive were unlikely to be infectious at time of sampling. Development of screening programmes must balance the potential to identify additional cases based upon likely prevalence, expanding the symptoms list to encourage HCW testing, with resource implications and risks of excluding those unlikely to be infectious with positive tests. / Funding: Public Health England

Drug-resistant genotypes and multi-clonality in Plasmodium falciparum analysed by direct genome sequencing from peripheral blood of malaria patients.

Naturally acquired blood-stage infections of the malaria parasite Plasmodium falciparum typically harbour multiple haploid clones. The apparent number of clones observed in any single infection depends on the diversity of the polymorphic markers used for the analysis, and the relative abundance of rare clones, which frequently fail to be detected among PCR products derived from numerically dominant clones. However, minority clones are of clinical interest as they may harbour genes conferring drug resistance, leading to enhanced survival after treatment and the possibility of subsequent therapeutic failure. We deployed new generation sequencing to derive genome data for five non-propagated parasite isolates taken directly from 4 different patients treated for clinical malaria in a UK hospital. Analysis of depth of coverage and length of sequence intervals between paired reads identified both previously described and novel gene deletions and amplifications. Full-length sequence data was extracted for 6 loci considered to be under selection by antimalarial drugs, and both known and previously unknown amino acid substitutions were identified. Full mitochondrial genomes were extracted from the sequencing data for each isolate, and these are compared against a panel of polymorphic sites derived from published or unpublished but publicly available data. Finally, genome-wide analysis of clone multiplicity was performed, and the number of infecting parasite clones estimated for each isolate. Each patient harboured at least 3 clones of P. falciparum by this analysis, consistent with results obtained with conventional PCR analysis of polymorphic merozoite antigen loci. We conclude that genome sequencing of peripheral blood P. falciparum taken directly from malaria patients provides high quality data useful for drug resistance studies, genomic structural analyses and population genetics, and also robustly represents clonal multiplicity

The global, regional, and national burden of oesophageal cancer and its attributable risk factors in 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

Background Oesophageal cancer is a common and often fatal cancer that has two main histological subtypes: oesophageal squamous cell carcinoma and oesophageal adenocarcinoma. Updated statistics on the incidence and mortality of oesophageal cancer, and on the disability-adjusted life-years (DALYs) caused by the disease, can assist policy makers in allocating resources for prevention, treatment, and care of oesophageal cancer. We report the latest estimates of these statistics for 195 countries and territories between 1990 and 2017, by age, sex, and Socio-demographic Index (SDI), using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD). Methods We used data from vital registration systems, vital registration-samples, verbal autopsy records, and cancer registries, combined with relevant modelling, to estimate the mortality, incidence, and burden of oesophageal cancer from 1990 to 2017. Mortality-to-incidence ratios (MIRs) were estimated and fed into a Cause of Death Ensemble model (CODEm) including risk factors. MIRs were used for mortality and non-fatal modelling. Estimates of DALYs attributable to the main risk factors of oesophageal cancer available in GBD were also calculated. The proportion of oesophageal squamous cell carcinoma to all oesophageal cancers was extracted by use of publicly available data, and its variation was examined against SDI, the Healthcare Access and Quality (HAQ) Index, and available risk factors in GBD that are specific for oesophageal squamous cell carcinoma (eg, unimproved water source and indoor air pollution) and for oesophageal adenocarcinoma (gastro-oesophageal reflux disease). Findings There were 473 000 (95% uncertainty interval [95% UI] 459 000–485 000) new cases of oesophageal cancer and 436 000 (425 000–448 000) deaths due to oesophageal cancer in 2017. Age-standardised incidence was 5·9 (5·7–6·1) per 100 000 population and age-standardised mortality was 5·5 (5·3–5·6) per 100 000. Oesophageal cancer caused 9·78 million (9·53–10·03) DALYs, with an age-standardised rate of 120 (117–123) per 100 000 population. Between 1990 and 2017, age-standardised incidence decreased by 22·0% (18·6–25·2), mortality decreased by 29·0% (25·8–32·0), and DALYs decreased by 33·4% (30·4–36·1) globally. However, as a result of population growth and ageing, the total number of new cases increased by 52·3% (45·9–58·9), from 310 000 (300 000–322 000) to 473 000 (459 000–485 000); the number of deaths increased by 40·0% (34·1–46·3), from 311 000 (301 000–323 000) to 436 000 (425 000–448 000); and total DALYs increased by 27·4% (22·1–33·1), from 7·68 million (7·42–7·97) to 9·78 million (9·53–10·03). At the national level, China had the highest number of incident cases (235 000 [223 000–246 000]), deaths (213 000 [203 000–223 000]), and DALYs (4·46 million [4·25–4·69]) in 2017. The highest national-level age-standardised incidence rates in 2017 were observed in Malawi (23·0 [19·4–26·5] per 100 000 population) and Mongolia (18·5 [16·4–20·8] per 100 000). In 2017, age-standardised incidence was 2·7 times higher, mortality 2·9 times higher, and DALYs 3·0 times higher in males than in females. In 2017, a substantial proportion of oesophageal cancer DALYs were attributable to known risk factors: tobacco smoking (39·0% [35·5–42·2]), alcohol consumption (33·8% [27·3–39·9]), high BMI (19·5% [6·3–36·0]), a diet low in fruits (19·1% [4·2–34·6]), and use of chewing tobacco (7·5% [5·2–9·6]). Countries with a low SDI and HAQ Index and high levels of indoor air pollution had a higher proportion of oesophageal squamous cell carcinoma to all oesophageal cancer cases than did countries with a high SDI and HAQ Index and with low levels of indoor air pollution. Interpretation Despite reductions in age-standardised incidence and mortality rates, oesophageal cancer remains a major cause of cancer mortality and burden across the world. Oesophageal cancer is a highly fatal disease, requiring increased primary prevention efforts and, possibly, screening in some high-risk areas. Substantial variation exists in age-standardised incidence rates across regions and countries, for reasons that are unclear.publishedVersio

Modelling the effects of boundary walls on the fire dynamics of informal settlement dwellings

AbstractCharacterising the risk of the fire spread in informal settlements relies on the ability to understand compartment fires with boundary conditions that are significantly different to normal residential compartments. Informal settlement dwellings frequently have thermally thin and leaky boundaries. Due to the unique design of these compartments, detailed experimental studies were conducted to understand their fire dynamics. This paper presents the ability of FDS to model these under-ventilated steel sheeted fire tests. Four compartment fire tests were modelled with different wall boundary conditions, namely sealed walls (no leakage), non-sealed walls (leaky), leaky walls with cardboard lining, and highly insulated walls; with wood cribs as fuel and ISO-9705 room dimensions. FDS managed to capture the main fire dynamics and trends both qualitatively and quantitatively. However, using a cell size of 6 cm, the ability of FDS to accurately model the combustion at locations with high turbulent flows (using the infinitely fast chemistry mixing controlled combustion model), and the effect of leakage, was relatively poor and both factors should be further studied with finer LES filter width. Using the validated FDS models, new flashover criteria for thermally thin compartments were defined as a combination of critical hot gas layer and wall temperatures. Additionally, a parametric study was conducted to propose an empirical correlation to estimate the onset Heat Release Rate required for flashover, as current knowledge fails to account properly for large scale compartments with thermally thin boundaries. The empirical correlation is demonstrated to have an accuracy of ≈ ± 10% compared with the FDS models