Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 10¹³ to 10⁵ Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.     

Coexistencia de artritis séptica y microcristalina: un reto diagnóstico. A propósito de 25 casos

ObjectiveSeptic arthritis is a medical emergency and crystal-induced arthritis is a risk factor for its development. If both occur simultaneously, crystal-induced arthritis may mask the diagnosis of infection and delay antibiotic therapy.MethodRetrospective analysis of patients with coexistence of septic and crystal-induced arthritis. We included only patients with isolation of crystals in synovial fluid analysis and positive culture of synovial fluid and/or blood culture.ResultsA total of 25 patients (17 men and 8 women) with a mean age of 67 years. The most commonly affected joint was the knee. In synovial fluid cytological studies, the most frequently identified crystals were monosodium urate. Risk factors included diabetes and chronic renal failure. The most frequently isolated germs were methicillin-sensitive S. aureus (48%), methicillin-resistant S. aureus (12%) and Mycobacterium tuberculosis (12%). In all, 36% of subjects required surgical drainage (excluding those caused by M. tuberculosis). Clinical outcome was favorable in 56%, although intercurrent complications were usual (40%). Mortality was 8%.ConclusionsCoexistence of septic and crystal-induced arthritis represents a diagnostic challenge and requires a high index of suspicion. Gout was the most prevalent crystal-induced arthritis. S. aureus was the most commonly causative pathogen, with a high rate of methicillin-resistant S. aureus infection. If treated early, the outcome is usually favorable, making synovial fluid microbiological study imperative.     

Job hazards and respiratory symptoms in Hispanic female domestic cleaners

Abstract

The occupational hazards and respiratory symptoms of domestic cleaners in USA are largely unknown. We conducted a cross-sectional study among 56 Hispanic female domestic cleaner on their health status and frequency of cleaning products used and tasks performed. While women used multi-use products (60.0%) and toilet bowl cleaners (51.8%) most days of the week, many (39.3%) reported not using personal protective equipment while cleaning. Itchy/watery eyes (61.8%) and itchy nose (56.4%) were the most frequently reported symptoms. A history of physician-diagnosed asthma was reported by 14.3% while 33.9% had symptoms of bronchial hyperresponsiveness (BHR). In conclusion, this vulnerable population has high prevalence of physician-diagnosis asthma and BHR symptoms and is potentially exposed to myriad occupational hazards. Further research exploring associations between products use, cleaning tasks and respiratory symptoms is warranted.     

Dentistry, neurology and nephrology--what is the connection?

Case report A 28-year-old female patient was admitted because of painlessmacroscopic haematuria. Past history included severe mentalretardation and nystagmus. At age 17, a computed tomography(CT) scan of the brain showed an absent cerebellar vermis andcerebellar hypoplasia. There was no     

Replacement of adjacent missing anterior teeth with scalloped implants: a case report.

As the biological width is established around neighboring implants, there is a flattening of the interimplant bone and a change in the position of the soft tissue. As a result, a normal progression of papilla from natural teeth through the adjacent implant area is lost. This presentation describes various techniques and strategies to improve the aesthetic outcome of anterior implant restorations, together with the use of a scalloped implant designed to sustain the interdental bony peaks, and in doing so, maintain the interimplant papillae.     

Efficacy of epoetin-beta 30,000 IU/week in correcting anaemia in patients with gastrointestinal tumours subjected to concomitant chemoradiotherapy

Objective  

The aim of the project was to assess the effectiveness and safety of weekly epoetin-beta (EB) in patients with gastrointestinal cancer (GIC) subjected to concomitant chemoradiotherapy (CCTRT).