Physicochemical Properties of Organic Molecular Ferroelectric Diisopropylammonium Chloride Thin Films.

We fabricated ferroelectric films of the organic molecular diisopropylammonium chloride (DIPAC) using the dip-coating technique and characterized their properties using various methods. Fourier-transform infrared, scanning electron microscopy, and X-ray diffraction analysis revealed the structural features of the films. We also performed ab-initio calculations to investigate the electronic and polar properties of the DIPAC crystal, which were found to be consistent with the experimental results. In particular, the optical band gap of the DIPAC crystal was estimated to be around 4.5 eV from the band structure total density-of-states obtained by HSE06 hybrid functional methods, in good agreement with the value derived from the Tauc plot analysis (4.05 ± 0.16 eV). The films displayed an island-like morphology on the surface and showed increasing electrical conductivity with temperature, with a calculated thermal activation energy of 2.24 ± 0.03 eV. Our findings suggest that DIPAC films could be a promising alternative to lead-based perovskites for various applications such as piezoelectric devices, optoelectronics, sensors, data storage, and microelectromechanical systems.

Preparation and Characterization of Polymer Membranes Impregnated with Carbon Nanotubes for Olive Mill Wastewater.

In this study, polymer membrane(s) impregnated with carbon nanotubes (CNTs) were developed, characterized and evaluated for removing phenolic compounds from olive mill wastewater; thus, protecting the environment and public health. Polyethersulfone/functionalized, multi-walled carbon nanotube (PES/fCNTs) membranes were synthesized via the phase inversion method using PES and acid-treated CNTs. The prepared membranes were then characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and contact angle. Results obtained from this study indicate a more hydrophilic surface for the prepared PES/fCNTs membranes, with a higher pure water flux compared to the polyethersulfone (PES) membranes. In addition, the amount of fCNTs in the membranes was found to be the most significant factor affecting the morphology and water flux of the membranes. The PES/fCNTs membranes at 1 bar with 0 wt.% and 1 wt.% of CNTs showed water flux of 37.8 and 69.71 kg/h.m2, respectively. In addition, PES/fCNTs membranes with 0.5 wt.% fCNTs showed the highest total phenol content removal of 74%.

Photocatalytic Degradation of Methylene Blue Using Polymeric Membranes Based on Cellulose Acetate Impregnated with ZnO Nanostructures.

This paper studied the photocatalytic degradation of methylene blue (MB) using polymeric membrane impregnated with ZnO nanostructures under UV-light and sunlight irradiation. ZnO nanoparticles and ZnO nanowires were prepared using the hydrothermal technique. Cellulose acetate polymeric membranes were fabricated by the phase inversion method using dimethylformamide (DMF) as a solvent and ZnO nanostructures. The structural properties of the nanostructures and the membranes were investigated using XRD, SEM, FTIR, and TGA measurements. The membranes were tested for photocatalytic degradation of MB using a UV lamp and a sunlight simulator. The photocatalytic results under sunlight irradiation in the presence of cellulose acetate impregnated with ZnO nanoparticles (CA-ZnO-NP) showed a more rapid degradation of MB (about 75%) compared to the results obtained under UV-light irradiation degradation (about 30%). The results show that CA-ZnO-NP possesses the photocatalytic ability to degrade MB efficiently at different levels under UV-light and sunlight irradiation. Modified membranes with ZnO nanoparticles and ZnO nanowires were found to be chemically stable, recyclable, and reproducible. The addition of ZnO nanostructure to the cellulose membranes generally enhanced their photocatalytic activity toward MB, making these potential membranes candidates for removing organic pollutants from aqueous solutions.

Clinical Impact of Pretreatment Human Immunodeficiency Virus Drug Resistance in People Initiating Nonnucleoside Reverse Transcriptase Inhibitor-Containing Antiretroviral Therapy: A Systematic Review and Meta-analysis.

BACKGROUND: Increased access to antiretroviral therapy (ART) has resulted in rising levels of pretreatment human immunodeficiency virus drug resistance (PDR). This is the first systematic review and meta-analysis to assess the impact of PDR on treatment outcomes among people initiating nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART, including the combination of efavirenz (EFV), tenofovir (TDF), and lamivudine or emtricitabine (XTC). METHODS: We systematically reviewed studies and conference proceedings comparing treatment outcomes in populations initiating NNRTI-based ART with and without PDR. We conducted subgroup analyses by regimen: (1) NNRTIs + 2 nucleoside reverse transcriptase inhibitors (NRTIs), (2) EFV + 2 NRTIs, or (3) EFV/TDF/XTC; by population (children vs adults); and by definition of resistance (PDR vs NNRTI PDR). RESULTS: Among 6197 studies screened, 32 were analyzed (31 441 patients). We found that individuals with PDR initiating NNRTIs across all the subgroups had increased risk of virological failure compared to those without PDR. Risk of acquisition of new resistance mutations and ART switch was also higher in people with PDR. CONCLUSIONS: This review shows poorer treatment outcomes in the presence of PDR, supporting the World Health Organization's recommendation to avoid using NNRTIs in countries where levels of PDR are high.

The methodological quality of dose-response meta-analyses needed substantial improvement: a cross-sectional survey and proposed recommendations.

OBJECTIVES: To investigate methodological quality of published dose-response meta-analysis (DRMA) and explore study characteristics associated with the quality. STUDY DESIGN AND SETTING: We searched three databases for published DRMAs and used a modified AMSTAR (15 items) checklist to assess the methodological quality. We summarized the compliance of those DRMAs to the AMSTAR items and used multivariable regression analysis to explore the association between prespecified study characteristics with the overall methodological quality. RESULTS: We identified 529 DRMAs. Of the methodological quality items, six were well complied (80% or more) and six poorly complied (30% or fewer) by these DRMAs. The median score was nine points [first and third quartile: 7, 10] and only 64/529 had score over 10 points. Regression analysis suggested that studies with more authors (ß = 0.19; 95% confidence interval [CI]: 0.05, 0.33), published more recently (ß = 0.29; 95% CI: 0.21, 0.36), with financial support (ß = 0.41; 95% CI: 0.13, 0.70), conducted by authors from European (other regions vs. European, ß = -0.68; 95% CI: -1.05, -0.31) were associated with better methodological quality. CONCLUSION: The methodological quality of published DRMAs was suboptimal. Substantial efforts are warranted to improve the quality, including developing methodology guideline, involving more methodological trained authors, and so forth.

A cluster randomised trial of a classroom communication resource program to change peer attitudes towards children who stutter among grade 7 students.

BACKGROUND: Classroom-based stuttering intervention addressing negative peer attitudes, perceptions, teasing and bullying of children who stutter (CWS) is required as part of holistic stuttering management because of its occurrence in primary school. This study was conducted in 2017, in 10 primary schools in the Western Cape, South Africa within lower (second and third) and higher (fourth and fifth) quintiles. OBJECTIVES: The primary objective of this study was to determine treatment effect at six months after intervention of grade 7 participants (Classroom Communication Resource [CCR] intervention versus no CCR) using global Stuttering Resource Outcomes Measure (SROM) scores in school clusters. The secondary objective was to determine grade 7 participant treatment effect on the SROM subscales including Positive Social Distance (PSD), Social Pressure (SP) and Verbal Interaction (VI). The subgroup objective was to determine any difference in the primary outcome between schools between and across quintile clusters (lower and higher). METHODS: Once schools were stratified into lower and higher quintile (which are defined according to geographical location, fee per school and resources) subgroup clusters, schools were assigned randomly to control and intervention groups consisting of grade 7 participants who were typically aged ≥ 11 years. Teachers received 1 h of training before administering the single-dose CCR intervention over a 60-90-min session. The CCR intervention included a social story, role-play and discussion. All participants viewed a video of a CWS and stuttering was defined at baseline. The SROM measured peer attitudes at six months after intervention. Randomisation was stratified by quintile group using a 1:1 allocation ratio. Full blinding was not possible; however, the outcome assessor was partially blinded and the analyst was also blinded. Generalised estimating equations (GEE) was used assuming an exchangeable correlation structure to analyse the data adopting an intention-to-treat principle. Multiple imputation was used to handle missing data. Criterion for statistical significance was set at alpha = 0.05. RESULTS: Ten schools were randomly allocated to control (k = 5) and intervention groups (k = 5), with n = 223 participants allocated to intervention and n = 231 to control groups. A total of 454 participants completed the SROMs in control (n = 231) and intervention (n = 223) groups and were analysed at baseline and six months after intervention. There was no statistically significant difference on the global SROM score (mean difference - 0.11; 95% confidence interval [CI] - 1.56-1.34; p = 0.88). There were also no significant differences on SROM subscales: PSD (mean difference 1.04; 95% CI - 1.02-311; p = 0.32), SP (mean difference - 0.45; 95% CI - 1.22-0.26; p = 0.21) and VI (mean difference 0.05; 95% CI - 1.01-1.11; p = 0.93). Additionally, there was no significant subgroup effect on the global SROM score (lower versus higher quintile subgroups) (interaction p value = 0.52). No harms were noted or reported. CONCLUSION: No statistically significant differences were noted. It is possible that the time frame was too short to note changes in peer attitudes and that further study is required to confirm the findings of this study. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03111524 . Registered on 9 March 2017.

A pilot study to determine the feasibility of a cluster randomised controlled trial of an intervention to change peer attitudes towards children who stutter.

BACKGROUND:  While randomised controlled trials (RCTs) are considered the gold standard of research, prior study is needed to determine the feasibility of a future large-scale RCT study. Objectives: This pilot study, therefore, aimed to determine feasibility of an RCT by exploring: (1) procedural issues and (2) treatment effect of the Classroom Communication Resource (CCR), an intervention for changing peer attitudes towards children who stutter. Method: A pilot cluster stratified RCT design was employed whereby the recruitment took place first at school-level and then at individual level. The dropout rate was reported at baseline, 1 and 6 months post-intervention. For treatment effect, schools were the unit of randomisation and were randomised to receive either the CCR intervention administered by teachers or usual practice, using a 1:1 allocation ratio. The stuttering resource outcomes measure (SROM) measured treatment effect at baseline, 1 and 6 months post-intervention overall and within the constructs (positive social distance, social pressure and verbal interaction). Results: For school recruitment, 11 schools were invited to participate and 82% (n = 9) were recruited. Based on the school recruitment, N = 610 participants were eligible for this study while only n = 449 were recruited, where there was n = 183 in the intervention group and n = 266 in the control group. The dropout rate from recruitment to baseline was as follows: intervention, 23% (n = 34), and control, 6% (n = 15). At 1 month a dropout rate of 7% (n = 10) was noted in the intervention and 6% (n = 15) in the control group, whereas at 6 months, dropout rates of 7% (n = 10) and 17% (n = 44) were found in the intervention and control groups, respectively. For treatment effect on the SROM, the estimated mean differences between intervention and control groups were (95% Confidence Interval (CI): -1.07, 5.11) at 1 month and 3.01 (95% CI: -0.69, 6.69) at 6 months. A statistically significant difference was observed at 6 months on the VI subscale of the SROM, with 1.35 (95% CI: 0.58, 2.13). Conclusion: A high recruitment rate of schools and participants was observed with a high dropout rate of participants. Significant differences were only noted at 6 months post-intervention within one of the constructs of the SROM. These findings suggest that a future RCT study is warranted and feasible.

Hemosiderin in sputum macrophages may predict infective exacerbations of chronic obstructive pulmonary disease: a retrospective observational study.

BACKGROUND: Infective exacerbations of COPD are common and are accompanied by neutrophilic bronchitis in sputum. Increased respiratory iron content has been associated with respiratory tract infection, though it is unclear if this represents a predisposing factor for infection or the sequelae of inflammation. Iron overload, as assessed in the airways, may be an important biomarker for recurrent infective exacerbations of COPD. The purpose of our study was to determine if hemosiderin in sputum macrophages is related to infective exacerbations of COPD. METHODS: We undertook a retrospective observational study of 54 consecutive patients who presented with an exacerbation of COPD and had sputum examined including assessment for hemosiderin in alveolar macrophages. The relation between infective exacerbations in the previous two years and the percent of hemosiderin-positive macrophages was analyzed with linear regression. To account for the non-parametric distribution of infective exacerbations, negative binomial regression modelling was used to account for other covariates. RESULTS: The percent of hemosiderin positive alveolar macrophages (hemosiderin index), analyzed parametrically and non-parametrically, demonstrated a significant correlation with increasing numbers of infective exacerbations in the previous two years. In a multivariate regression analysis, hemosiderin index was an independent predictor of infective exacerbations. COPD patients with raised hemosiderin index (≥20%) had higher levels of sputum IL-6 compared to patients with lower levels (<20%). CONCLUSIONS: High hemosiderin index in sputum alveolar macrophages measured at the time of AECOPD may be related to the frequency of infective exacerbations of COPD.

Cerium oxide and iron oxide nanoparticles abolish the antibacterial activity of ciprofloxacin against gram positive and gram negative biofilm bacteria.

Metal oxide nanoparticles have been suggested as good candidates for the development of antibacterial agents. Cerium oxide (CeO2) and iron oxide (Fe2O3) nanoparticles have been utilized in a number of biomedical applications. Here, the antibacterial activity of CeO2 and Fe2O3 nanoparticles were evaluated on a panel of gram positive and gram negative bacteria in both the planktonic and biofilm cultures. Additionally, the effect of combining CeO2 and Fe2O3 nanoparticles with the broad spectrum antibiotic ciprofloxacin on tested bacteria was investigated. Thus, minimum inhibitory concentrations (MICs) of CeO2 and Fe2O3 nanoparticles that are required to inhibit bacterial planktonic growth and bacterial biofilm, were evaluated, and were compared to the MICs of the broad spectrum antibiotic ciprofloxacin alone or in the presence of CeO2 and Fe2O3 nanoparticles. Results of this study show that both CeO2 and Fe2O3 nanoparticles fail to inhibit bacterial growth and biofilm biomass for all the bacterial strains tested. Moreover, adding CeO2 or Fe2O3 nanoparticles to the broad spectrum antibiotic ciprofloxacin almost abolished its antibacterial activity. Results of this study suggest that CeO2 and Fe2O3 nanoparticles are not good candidates as antibacterial agents, and they could interfere with the activity of important antibiotics.

Magnetic nanoparticles: surface effects and properties related to biomedicine applications.

Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10-100 µm), viruses, genes, down to proteins (3-50 nm). The optimization of the nanoparticles' size, size distribution, agglomeration, coating, and shapes along with their unique magnetic properties prompted the application of nanoparticles of this type in diverse fields. Biomedicine is one of these fields where intensive research is currently being conducted. In this review, we will discuss the magnetic properties of nanoparticles which are directly related to their applications in biomedicine. We will focus mainly on surface effects and ferrite nanoparticles, and on one diagnostic application of magnetic nanoparticles as magnetic resonance imaging contrast agents.

Stability of the Shape of a Viscous Drop under Buoyancy-Driven Translation in a Hele-Shaw Cell.

It has been shown (N. R. Gupta, A. Nadim, H. Haj-Hariri, and A. Borhan, J. Colloid Interface Sci. 218, 338 1999) that a circular drop translating in a Hele-Shaw cell under the action of gravity is linearly stable for nonzero interfacial tension. In this paper, we use the boundary integral method to examine the nonlinear evolution of the shape of initially noncircular drops translating in a Hele-Shaw cell. For prolate initial deformations, it is found that the drop reverts to a circular shape for all finite Bond numbers considered. Initially oblate drops, on the other hand, are found to become unstable and break up if the initial shape perturbation is of sufficiently large magnitude. The critical conditions for the onset of drop breakup are examined in terms of the magnitude of the initial deformation as a function of Bond number. Two branches of marginal stability are identified and the effects of viscosity ratio and asymmetric initial perturbations on the stability diagram are discussed. Copyright 2000 Academic Press.

Effect of Insoluble Surfactants on the Pressure-Driven Motion of a Drop in a Tube in the Limit of High Surface Coverage.

The effect of surfactants on the axisymmetric pressure-driven motion of a droplet in a tube is investigated under low Reynolds number conditions. In the presence of surface-active impurities, the motion of the drop results in constant redistribution of the adsorbed surfactant along the interface by convection and diffusion, leading to nonuniformities in interfacial tension (i.e., Marangoni stresses) which modify the viscous stress balance at the interface. These, in turn, affect the mobility of the drop and its steady or transient shape deformations. In this study, the steady-state behavior of such a drop is examined in the presence of nondilute concentrations of bulk-insoluble surfactants on the surface of the drop. The boundary integral method is used in conjunction with a finite-difference scheme to solve the unsteady surface convective-diffusion equation for surfactant transport. The Frumkin adsorption framework is used to explore the effects of monolayer saturation and nonideal surfactant interactions on the steady drop shape and speed in the limit of high surface coverage. It is found that for surfactants with strong cohesive interactions, the drop mobility increases with increasing surface coverage, attaining maximum mobility at about 50% initial coverage. Furthermore, surface-convection-dominated systems with strong cohesive interactions exhibit surface flow patterns corresponding to the formation of a stagnant cap at the trailing end of the drop. All other systems exhibit surface flow patterns corresponding to uniform retardation of interface mobility as a fully immobilized interface is approached with increasing surface convection. Copyright 1999 Academic Press.

On the Linear Stability of a Circular Drop Translating in a Hele-Shaw Cell.

For the buoyancy-driven motion of a drop in a Hele-Shaw cell, a circle is an exact solution for the shape of the drop. The stability of the shape of a circular drop translating in a Hele-Shaw cell under the action of gravity is investigated. It is shown that for nonzero interfacial tension, the circular shape is linearly stable. Copyright 1999 Academic Press.

Upper ureteral reconstructive surgery.

Upper ureteral reconstructive surgery encompasses a wide variety of procedures directed at the correction of abnormal processes and structural defects in the proximal ureter. Although some of these techniques have strict indications for specific causes, technical innovations have led to development of numerous alternatives in upper ureteral reconstructive surgery. These innovations provide the practicing urologist with various options from which to choose for the management of upper ureteral disease.

Anatomical basis of latissimus dorsi myocutaneous flap: clinical applications.

The anatomical study was carried out using 40 preserved cadaveric specimens of latissimus dorsi myocutaneous flaps. It included dissections, angiographies and tissue clearing after arterial injection with latex. The results proved that the dominant vascular supply, the thoracodorsal a., has an almost constant pattern of intramuscular distribution. In addition, there are two sets of segmental pedicles, from the intercostal and lumbar vessels, supplying the medial third of the muscle. The accurate localization of the intramuscular distribution of the thoracodorsal a. permitted the proper design of several island flaps with competent vascularity. The designed flaps were successfully applied in 10 cases for reconstruction of breast, axilla, neck and chest wall.