Novel smart composite materials for industrial wastewater treatment and reuse

Abstract: With the current levels of industrial development it is very difficult to prevent organic pollutants and toxic heavy metals from contaminating water. Thus purification of contaminated industrial water and its reuse is a global concern. The present study highlights application of a novel standalone technology in the form of polymers that efficiently extract a range of organic and inorganic impurities simultaneously for reuse of industrial effluent. Previous studies have focused on water soluble synthetic polymers for removal of organic contaminants, while biodegradable polymers are being used for extraction of toxic metals from water. Our earlier reports already describe a combination of synthetic and natural polymers with the ability to eliminate organic and inorganic spiked impurities from water on a lab scale. In the present work a series of novel smart composite materials have been synthesized and fully characterized. The avant-garde novelty of these materials for simultaneous removal of organic impurities such as phenols, anhydrides, textile dyes, pesticides, herbicides, antibiotics and inorganic heavy metals has been demonstrated and the novel polymers have shown a removal efficiency of more than 90% for each of the contaminants. Furthermore, the established 4-cycle reusability and an extensive reduction in levels of chemical oxygen demand suggests these materials would act as an improvement to the current methods for treating effluent water. The high reproducibility in synthesis, properties and elimination spectrum brands them as promising materials for industrial water remediation and reuse

Nanomechanical Characterization of Indium Nano/Microwires

Nanomechanical properties of indium nanowires like structures fabricated on quartz substrate by trench template technique, measured using nanoindentation. The hardness and elastic modulus of wires were measured and compared with the values of indium thin film. Displacement burst observed while indenting the nanowire. ‘Wire-only hardness’ obtained using Korsunsky model from composite hardness. Nanowires have exhibited almost same modulus as indium thin film but considerable changes were observed in hardness value

Repeated Assessments of Informed Consent Comprehension among HIV-Infected Participants of a Three-Year Clinical Trial in Botswana

Informed consent (IC) has been an international standard for decades for the ethical conduct of clinical trials. Yet frequently study participants have incomplete understanding of key issues, a problem exacerbated by language barriers or lack of familiarity with research concepts. Few investigators measure participant comprehension of IC, while even fewer conduct interim assessments once a trial is underway.We assessed comprehension of IC using a 20-question true/false quiz administered in 6-month intervals in the context of a placebo-controlled, randomized trial for the prevention of tuberculosis among HIV-infected adults in Botswana (2004-2009). Quizzes were offered in both Setswana and English. To enroll in the TB trial, participants were required to have ≥ 16/20 correct responses. We examined concepts understood and the degree to which understanding changed over three-years. We analyzed 5,555 quizzes from 1,835 participants. The participants' highest education levels were: 28% primary, 59% secondary, 9% tertiary and 7% no formal education. Eighty percent of participants passed the enrollment quiz (Quiz1) on their first attempt and the remainder passed on their second attempt. Those having higher than primary education and those who took the quiz in English were more likely to receive a passing score on their first attempt (adjusted odds ratios and 95% confidence intervals, 3.1 (2.4-4.0) and 1.5 (1.2, 1.9), respectively). The trial's purpose or procedures were understood by 90-100% of participants, while 44-77% understood randomization, placebos, or risks. Participants who failed Quiz1 on their initial attempt were more likely to fail quizzes later in the trial. Pass rates improved with quiz re-administration in subsequent years.Administration of a comprehension quiz at enrollment and during follow-up was feasible in a large, international collaboration and efficiently determined IC comprehension by trial participants. Strategies to improve understanding of concepts like placebos and randomization are needed. Comprehension assessments throughout a study may reinforce key concepts

Strategies for Treating Latent Multiple-Drug Resistant Tuberculosis: A Decision Analysis

BACKGROUND: The optimal treatment for latent multiple-drug resistant tuberculosis infection remains unclear. In anticipation of future clinical trials, we modeled the expected performance of six potential regimens for treatment of latent multiple-drug resistant tuberculosis. METHODS: A computerized Markov model to analyze the total cost of treatment for six different regimens: Pyrazinamide/ethambutol, moxifloxacin monotherapy, moxifloxacin/pyrazinamide, moxifloxacin/ethambutol, moxifloxacin/ethionamide, and moxifloxacin/PA-824. Efficacy estimates were extrapolated from mouse models and examined over a wide range of assumptions. RESULTS: In the base-case, moxifloxacin monotherapy was the lowest cost strategy, but moxifloxacin/ethambutol was cost-effective at an incremental cost-effectiveness ratio of $21,252 per quality-adjusted life-year. Both pyrazinamide-containing regimens were dominated due to their toxicity. A hypothetical regimen of low toxicity and even modest efficacy was cost-effective compared to "no treatment." CONCLUSION: In our model, moxifloxacin/ethambutol was the preferred treatment strategy under a wide range of assumptions; pyrazinamide-containing regimens fared poorly because of high rates of toxicity. Although more data are needed on efficacy of treatments for latent MDR-TB infection, data on toxicity and treatment discontinuation, which are easier to obtain, could have a substantial impact on public health practice

The effects of material formulation and manufacturing process on mechanical and thermal properties of epoxy/clay nanocomposites

A holistic study was conducted to investigate the combined effect of three different pre-mixing processes, namely mechanical mixing, ultrasonication and centrifugation, on mechanical and thermal properties of epoxy/clay nanocomposites reinforced with different platelet-like montmorillonite (MMT) clays (Cloisite Na+, Cloisite 10A, Cloisite 15 or Cloisite 93A) at clay contents of 3–10 wt%. Furthermore, the effect of combined pre-mixing processes and material formulation on clay dispersion and corresponding material properties of resulting composites was investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), flexural and Charpy impact tests, Rockwell hardness tests and differential scanning calorimetry (DSC). A high level of clay agglomeration and partially intercalated/exfoliated clay structures were observed regardless of clay type and content. Epoxy/clay nanocomposites demonstrate an overall noticeable improvement of up to 10 % in the glass transition temperature (Tg) compared to that of neat epoxy, which is interpreted by the inclusion of MMT clays acting as rigid fillers to restrict the chain mobility of epoxy matrices. The impact strength of epoxy/clay nanocomposites was also found to increase by up to 24 % with the addition of 3 wt% Cloisite Na+ clays. However, their flexural strength and hardness diminished when compared to those of neat epoxy, arising from several effects including clay agglomeration, widely distributed microvoids and microcracks as well as weak interfacial bonding between clay particles and epoxy matrices, as confirmed from TEM and SEM results. Overall, it is suggested that an improved technique should be used for the combination of pre-mixing processes in order to achieve the optimal manufacturing condition of uniform clay dispersion and minimal void contents

The Cost-Effectiveness of Tuberculosis Preventive Therapy for HIV-Infected Individuals in Southern India: A Trial-Based Analysis

Regimens for isoniazid-based preventive therapy (IPT) for tuberculosis (TB) in HIV-infected individuals have not been widely adopted given concerns regarding efficacy, adherence and drug resistance. Further, the cost-effectiveness of IPT has not been studied in India.We used an HIV/TB model to project TB incidence, life expectancy, cost and incremental cost-effectiveness of six months of isoniazid plus ethambutol (6EH), thirty-six months of isoniazid (36H) and no IPT for HIV-infected patients in India. Model input parameters included a median CD4 count of 324 cells/mm(3), and a rate ratio of developing TB of 0.35 for 6EH and 0.22 for 36H at three years as compared to no IPT. Results of 6EH and 36H were also compared to six months of isoniazid (6H), three months of isoniazid plus rifampin (3RH) and three months of isoniazid plus rifapentine (3RPTH).Projected TB incidence decreased in the 6EH and 36H regimens by 51% and 62% respectively at three-year follow-up compared to no IPT. Without IPT, projected life expectancy was 136.1 months at a lifetime per person cost of $5,630. 6EH increased life expectancy by 0.8 months at an additional per person cost of$100 (incremental cost-effectiveness ratio (ICER) of $1,490/year of life saved (YLS)). 36H further increased life expectancy by 0.2 months with an additional per person cost of$55 (ICER of $3,120/YLS). The projected clinical impact of 6EH was comparable to 6H and 3RH; however when compared to these other options, 6EH was no longer cost-effective given the high cost of ethambutol. Results were sensitive to baseline CD4 count and adherence.Three, six and thirty-six-month regimens of isoniazid-based therapy are effective in preventing TB. Three months of isoniazid plus rifampin and six-months of isoniazid are similarly cost-effective in India, and should be considered part of HIV care

Consensual unions in Central America : historical continuities and new emerging patterns

Central America has a long history of family formation via consensual union instead of formal marriage. The historically high levels of cohabitation have persisted throughout the twentieth century up to the present day and can be traced in the remarkably high levels of nonmarital childbearing in the region. This chapter reviews past and recent trends in the prevalence of consensual unions in six Central American countries - Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama - in order to ascertain whether cohabitation has reached an upper ceiling in the region and whether the apparent stability at the aggregate level conceals significant changes in cohabiting patterns across social groups. The analyses reveal that the expansion of cohabitation has not come to an end so far, largely because of the recent increase in consensual unions among the higher educated strata. The historically negative educational gradient of cohabitation remains largely in place, but differentials in union patterns across countries and across social groups have narrowed considerably in the past two decades