The Effect of Grain Refining of Primary Aluminum on the Fluidity of Al-Si Casting Alloys

Aluminium alloys, and particularly aluminium silicon alloys, have found extensive use in engineering applications. Improving the mechanical properties of the cast alloys is important. One of the means of achieving this is by grain refinement using grain refiners. The grain refiners affect the fluidity, and consequently solidification, of the alloys. In this study, the fluidity of nineteen Al-Si alloys made with silicon of 99.999% purity and aluminum of 99.999% purity were investigated using a straight channels mold. The casting modulus of the channels varied between 0.2 mm and 2.9 mm. Using the same quality of materials, Ti-B-Al was added to alloys with silicon content between 0% and 16%. In the 0.91 mm modulus channel a decrease varying from 50% to 2% was observed in the solid solution alloys while in the hypo-eutectic alloys fluidity decreased by 16% to 45%. However, in the hyper-eutectic alloys, fluidity increased by 8% to 18%. Keywords: Fluidity, casting, grain-refinement, solidification DOI: 10.7176/CMR/13-1-05 Publication date: April 30th 202

Condom Use among Young African American Men: Implications for Planning Interventions

Condom Use among Young African American Men: Implications for Planning Interventions Sexually transmitted diseases, including HIV, continue to present significant public health problems affecting young people in the United States, especially African Americans. While African Americans make up about 12% of the U.S. population, in 2010 they accounted for 44% of new HIV infections in 2010 and 48% of all persons living with AIDS in 2007. The 2010 data shows that of these new cases, 38% occurred among African American males ages 13-24 years old. Correct condom use remains a challenge in this population and efforts to increase condom use among minority males has been a formidable challenge. This paper reports the results of formative research conducted in order to guide the development of an intervention to increase consistent, effective condom use for young African American males. Methods: A snowball sampling approach was used to recruit participants. African American males, ages 18-24, who self-reported as sexually active were eligible to participate in one of four focus groups or one of six individual interviews. All study events were conducted at community locations. Each event was audiotaped and notes were taken. Analysis was performed using using NVivo-9. The coding strategy included emic and etic codes and a coding tree was developed which was used to identify themes. Results: A total of 36 African American males between the ages of 18-24 (mean 20.7 years) took part. In general, participants felt condom use was highly influenced by contextual factors including partner interest, partner communication, length of relationship and trust. Condom use was also influenced by a sense of invincibility and being caught up in the moment. Notably, most sexual activity occurred outside of a relationship, most often within the party scene or as quickly arranged hook-ups. Analysis: In order to ensure maximum impact on the development of the intervention, the results from this formative phase were viewed through the Transtheoretical Model of Behavior Change (TTM) and most participants would be described as being in the pre-contemplation or contemplation stages of behavioral change. While all participants expressed some understanding of the risks of unprotected sex, many did not connect risks to consequences. While the data did not indicate that condom use behavior was likely to change in the short-term (less than 6 months), several participants were contemplating making a change. Discussion: The snowball sampling approach allowed us to understand the participants’ social network and allowed us to consider social influences as well as about individual attitudes and beliefs. In the TTM frame, interventions designed for this population need to include contemplators and pre-contemplators and should focus on modification of cognition, affect and behaviors. Our research also shows that several of the underlying assumptions of TTM are at odds with the framework within which sex often occurs for this population and condom use decisions are highly influenced by the social context. In light of the results, the intervention placed condom use into a health promotion context. It combines group activities and one-on-one interaction. Group activities can impact shared values and beliefs and, thus, the intervention builds social support for behavior changes while addressing individual capacity

HIV sexual risk behaviors and perception of risk among college students: implications for planning interventions

<p>Abstract</p> <p>Background</p> <p>The college environment offers great opportunity for HIV high-risk behaviors, including unsafe sex and multiple partnerships. While the overall incidence of HIV infection has seen some decline in recent years, rates of HIV infection among young adults have not seen a proportionate decline. As in the general population, African American young adults have been disproportionately affected by the HIV/AIDS epidemic. This study examined the sexual risk behaviors and perception of HIV risk of students in a predominantly African American commuter urban university in the Midwest.</p> <p>Methods</p> <p>Students enrolled in randomly selected general education courses completed a paper and pencil survey. Data were collected in Fall 2007, and univariate, bivariate, and multivariate analyses were conducted using SPSS for Windows v.16.</p> <p>Results</p> <p>The sample included 390 students, the majority (83%) of whom were never married and 87% were sexually experienced. Among males reporting male partnerships those who used marijuana (OR = 17.5, p = 0.01) and those who used alcohol along with illegal drugs (OR = 8.8, p = 0.03) were significantly more likely to report multiple partnerships. Among females reporting male partnerships, those 30 years and older were significantly less likely (OR = 0.09, p = 0.03) to report having multiple male partners. There were significant differences in condom use last sex (p = 0.01) and consistent condom use (p = 0.002) among the different age groups. Older students were less likely to report condom use. Females age 30 years and older (OR = 3.74, p = 0.05) and respondents age 2029 years (OR = 2.41, p = 0.03) were more likely to report inconsistent condom use than those below 20 years. Marijuana use was correlated with inconsistent condom use (p = 0.02) and alcohol with not using condom last sex among females. Perception of HIV risk was generally poor with 54% of those age 30 years and older, 48.1% of 2029 year olds, and 57.9% of those below the age of 20 years perceived themselves as not having any chance of being infected with HIV. Predictors of moderate/good perception of HIV risk were drug and alcohol use, inconsistent condom use, and multiple partnerships.</p> <p>Conclusion</p> <p>Students in the study sample engaged in various HIV risk behaviors but have a poor appreciation of their risk of HIV infection. While low rates of condom use was a problem among older students (30 years and older), multiple partnerships were more common among younger students, and marijuana and alcohol use were related to low condom use among females. Our findings support the need for targeted HIV prevention interventions on college campuses.</p

Readability and test-retest reliability of a psychometric instrument designed to assess HIV/AIDS attitudes, beliefs, behaviours and sources of HIV prevention information of young adults

Objective: This comparative study evaluated the readability and test-retest reliability of a questionnaire designed to assess the attitudes, beliefs behaviours and sources of information about HIV/AIDS among young adults recruited from universities in the United States of America (USA), Turkey and South Africa. Design/Setting: The instrument was administered on two occasions, within a two week interval, to 219 university students in the USA (n = 66), Turkey (n = 53) and South Africa (n = 100). Method: The psychometric instrument developed has five major subscales: demographic, HIV/AIDS attitudes and beliefs, HIV risk sexual behaviour, alcohol and drug use, and HIV sources of information. Results: The instrument’s readability evaluation revealed a Flesch-Kincaid score (literacy difficulty level of the questionnaire) of 8.4, indicating that respondents would need an eighth grade reading level to understand the survey. The overall test-retest reliability coefficients for the items on the demographic subscale were generally high (0.893–0.997). Similarly, high test-retest reliability was obtained for the HIV risk sexual behaviour (0.738–0.996) and the alcohol and drug use (0.562–1.000) subscales. Much lower test-retest reliability was obtained for the HIV/AIDS attitudes and beliefs (0.32–0.80), and sources of information about HIV/AIDS (0.370–0.892) subscales. Conclusion: We found no discernible difference in the reliability data among the respondents from the three countries. The instrument should be of interest to clinicians and researchers investigating the HIV risk behaviours of young adults and older age groups with an eighth grade reading level. The availability of this instrument may enhance HIV population and intervention studies internationally.Web of Scienc

Efficacy and safety of nitazoxanide plus atazanavir/ritonavir for the treatment of moderate to severe COVID-19 (NACOVID): A structured summary of a study protocol for a randomised controlled trial

Abstract Objectives To investigate the efficacy and safety of repurposed antiprotozoal and antiretroviral drugs, nitazoxanide and atazanavir/ritonavir, in shortening the time to clinical improvement and achievement of SARS-CoV-2 polymerase chain reaction (PCR) negativity in patients diagnosed with moderate to severe COVID-19. Trial design This is a pilot phase 2, multicentre 2-arm (1:1 ratio) open-label randomised controlled trial. Participants Patients with confirmed COVID-19 diagnosis (defined as SARS-CoV-2 PCR positive nasopharyngeal swab) will be recruited from four participating isolation and treatment centres in Nigeria: two secondary care facilities (Infectious Diseases Hospital, Olodo, Ibadan, Oyo State and Specialist State Hospital, Asubiaro, Osogbo, Osun State) and two tertiary care facilities (Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State and Olabisi Onabanjo University Teaching Hospital, Sagamu, Ogun State). These facilities have a combined capacity of 146-bed COVID-19 isolation and treatment ward. Inclusion criteria Confirmation of SARS-CoV-2 infection by PCR test within two days before randomisation and initiation of treatment, age bracket of 18 and 75 years, symptomatic, able to understand study information and willingness to participate. Exclusion criteria include the inability to take orally administered medication or food, known hypersensitivity to any of the study drugs, pregnant or lactating, current or recent (within 24 hours of enrolment) treatment with agents with actual or likely antiviral activity against SARS-CoV-2, concurrent use of agents with known or suspected interaction with study drugs, and requiring mechanical ventilation at screening. Intervention and comparator Participants in the intervention group will receive 1000 mg of nitazoxanide twice daily orally and 300/100 mg of atazanvir/ritonavir once daily orally in addition to standard of care while participants in the control group will receive only standard of care. Standard of care will be determined by the physician at the treatment centre in line with the current guidelines for clinical management of COVID-19 in Nigeria. Main outcome measures Main outcome measures are: (1) Time to clinical improvement (defined as time from randomisation to either an improvement of two points on a 10-category ordinal scale (developed by the WHO Working Group on the Clinical Characterisation and Management of COVID-19 infection) or discharge from the hospital, whichever came first); (2) Proportion of participants with SARS-CoV-2 polymerase chain reaction (PCR) negative result at days 2, 4, 6, 7, 14 and 28; (3) Temporal patterns of SARS-CoV-2 viral load on days 2, 4, 6, 7, 14 and 28 quantified by RT-PCR from saliva of patients receiving standard of care alone versus standard of care plus study drugs. Randomisation Allocation of participants to study arm is randomised within each site with a ratio 1:1 based on randomisation sequences generated centrally at Obafemi Awolowo University. The model was implemented in REDCap and includes stratification by age, gender, viral load at diagnosis and presence of relevant comorbidities. Blinding None, this is an open-label trial. Number to be randomised (sample size) 98 patients (49 per arm). Trial status Regulatory approval was issued by the National Agency for Food and Drug Administration and Control on 06 October 2020 (protocol version number is 2.1 dated 06 August 2020). Recruitment started on 9 October 2020 and is anticipated to end before April 2021. Trial registration The trial has been registered on ClinicalTrials.gov (July 7, 2020), with identifier number NCT04459286 and on Pan African Clinical Trials Registry (August 13, 2020), with identifier number PACTR202008855701534. Full protocol The full protocol is attached as an additional file which will be made available on the trial website. In the interest of expediting dissemination of this material, the traditional formatting has been eliminated, and this letter serves as a summary of the key elements in the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2). </jats:sec

A randomized, open-label trial of combined nitazoxanide and atazanavir/ritonavir for mild to moderate COVID-19

BackgroundThe nitazoxanide plus atazanavir/ritonavir for COVID-19 (NACOVID) trial investigated the efficacy and safety of repurposed nitazoxanide combined with atazanavir/ritonavir for COVID-19.MethodsThis is a pilot, randomized, open-label multicenter trial conducted in Nigeria. Mild to moderate COVID-19 patients were randomly assigned to receive standard of care (SoC) or SoC plus a 14-day course of nitazoxanide (1,000 mg b.i.d.) and atazanavir/ritonavir (300/100 mg od) and followed through day 28. Study endpoints included time to clinical improvement, SARS-CoV-2 viral load change, and time to complete symptom resolution. Safety and pharmacokinetics were also evaluated (ClinicalTrials.gov ID: NCT04459286).ResultsThere was no difference in time to clinical improvement between the SoC (n = 26) and SoC plus intervention arms (n = 31; Cox proportional hazards regression analysis adjusted hazard ratio, aHR = 0.898, 95% CI: 0.492–1.638, p = 0.725). No difference was observed in the pattern of saliva SARS-CoV-2 viral load changes from days 2–28 in the 35% of patients with detectable virus at baseline (20/57) (aHR = 0.948, 95% CI: 0.341–2.636, p = 0.919). There was no significant difference in time to complete symptom resolution (aHR = 0.535, 95% CI: 0.251–1.140, p = 0.105). Atazanavir/ritonavir increased tizoxanide plasma exposure by 68% and median trough plasma concentration was 1,546 ng/ml (95% CI: 797–2,557), above its putative EC90 in 54% of patients. Tizoxanide was undetectable in saliva.ConclusionNitazoxanide co-administered with atazanavir/ritonavir was safe but not better than standard of care in treating COVID-19. These findings should be interpreted in the context of incomplete enrollment (64%) and the limited number of patients with detectable SARS-CoV-2 in saliva at baseline in this trial.Clinical trial registration[https://clinicaltrials.gov/ct2/show/NCT04459286], identifier [NCT04459286].</jats:sec

Data_Sheet_1_A randomized, open-label trial of combined nitazoxanide and atazanavir/ritonavir for mild to moderate COVID-19.docx

BackgroundThe nitazoxanide plus atazanavir/ritonavir for COVID-19 (NACOVID) trial investigated the efficacy and safety of repurposed nitazoxanide combined with atazanavir/ritonavir for COVID-19.MethodsThis is a pilot, randomized, open-label multicenter trial conducted in Nigeria. Mild to moderate COVID-19 patients were randomly assigned to receive standard of care (SoC) or SoC plus a 14-day course of nitazoxanide (1,000 mg b.i.d.) and atazanavir/ritonavir (300/100 mg od) and followed through day 28. Study endpoints included time to clinical improvement, SARS-CoV-2 viral load change, and time to complete symptom resolution. Safety and pharmacokinetics were also evaluated (ClinicalTrials.gov ID: NCT04459286).ResultsThere was no difference in time to clinical improvement between the SoC (n = 26) and SoC plus intervention arms (n = 31; Cox proportional hazards regression analysis adjusted hazard ratio, aHR = 0.898, 95% CI: 0.492–1.638, p = 0.725). No difference was observed in the pattern of saliva SARS-CoV-2 viral load changes from days 2–28 in the 35% of patients with detectable virus at baseline (20/57) (aHR = 0.948, 95% CI: 0.341–2.636, p = 0.919). There was no significant difference in time to complete symptom resolution (aHR = 0.535, 95% CI: 0.251–1.140, p = 0.105). Atazanavir/ritonavir increased tizoxanide plasma exposure by 68% and median trough plasma concentration was 1,546 ng/ml (95% CI: 797–2,557), above its putative EC90 in 54% of patients. Tizoxanide was undetectable in saliva.ConclusionNitazoxanide co-administered with atazanavir/ritonavir was safe but not better than standard of care in treating COVID-19. These findings should be interpreted in the context of incomplete enrollment (64%) and the limited number of patients with detectable SARS-CoV-2 in saliva at baseline in this trial.Clinical trial registration[https://clinicaltrials.gov/ct2/show/NCT04459286], identifier [NCT04459286].</p