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.     

An investigation into the architecture of the vastus medialis oblique muscle in athletic and sedentary individuals: An in vivo ultrasound study

There is thought to be a relationship between the vastus medialis oblique muscle (VMO) and patellofemoral pain syndrome (PFPS), a condition that has a high prevalence in young athletic individuals. Following a suggestion that there may be a link between the architecture of the VMO and an individual's activity level, the aim of this study was to determine any differences in two measurable parameters of the VMO between two populations with widely differing activity levels. The parameters measured were VMO fiber angle and insertion ratio, which is the proportion of the medial patellar border with VMO fibers inserting onto it (%). Eighty‐two knees from 26 athletic volunteers and 15 sedentary volunteers (aged 20–28 years) were assessed using ultrasound. Activity level was defined using the Tegner scoring system. The mean VMO angle (°) for the athletic group was significantly higher than for the sedentary group at 67.8° and 53.6°, respectively. There was no significant difference in insertion ratio between the athletic group, 43.0%, and the sedentary group, 39.5%. This study found that greater VMO fiber angles were seen in individuals with higher activity levels, exerting a stronger medial stabilizing force on the patella. This has important implications for the treatment of PFPS, particularly in athletic patients, which frequently focus on VMO strengthening exercises. Clin. Anat. 28:262–268, 2015. © 2014 Wiley Periodicals, Inc.     

Using ultrasound to teach anatomy in the undergraduate medical curriculum: an evaluation of the experiences of tutors and medical students

This paper describes the experiences of staff and students at two UK medical schools, who introduced portable ultrasound (PU) as an imaging technology to deliver clinical anatomy teaching and to aid skill development in interpretation of cross-sectional anatomy (CSA). A sonographer contributed to curriculum design and teaching, but mostly anatomy tutors delivered the teaching. This case study method evaluates staff and student perspectives on the ultrasound-based anatomy teaching. Quantitative data and qualitative data were collected and analysed. Staff were positive about the experience. They described their expectations for students and solutions for practical issues regarding the teaching, but were concerned about their competency in scanning and wanted bespoke training for sonoanatomy teaching. Curriculum development was accelerated through engagement with a sonographer and an ultrasound champion. Students were extremely positive about their experience; they valued the expertise of a sonographer who taught more challenging sonoanatomy, but were equally positive regarding teaching sessions led by well-trained anatomy tutors who taught more simple sonoanatomy. Students affirmed most tutors’ expectations that ultrasound could reinforce existing anatomical knowledge, added clinical contextualisation, but not that use of ultrasound (US) assisted in interpreting CSA. Students valued the introduction to the technology and found sonoimage interpretation challenging, but not insurmountable. Students wanted more instruction on ultrasound physics, an expansion of ultrasound curriculum, with smaller groups and opportunities to scan volunteers. These data support the case for the use of PU to deliver anatomy teaching and to prime medical students for later clinical encounters with PU.     

My patient is injured: identifying foreign bodies with ultrasound

Patients commonly present to the emergency department with a suspected retained foreign body, following penetrating injury. While plain radiography is often the first line in identifying radio-opaque foreign bodies, radiolucent foreign bodies such as wood and plastic can easily be missed. Furthermore, real-time visualization of such a foreign body can assist in its removal. This article evaluates the use of point-of-care ultrasound by emergency physicians in the identification and removal of soft-tissue foreign bodies along with describing the appropriate technique and highlighting the potential pitfalls. An illustrated case example is presented that highlights the benefits of point-of-care ultrasound foreign body detection and guided removal.     

Diagnosis of abdominal mural aortic thrombus following discovery of common femoral artery and vein thrombosis by point-of-care ultrasound

Acute limb ischemia (ALI) is a limb-threatening and life-threatening disease process. Mural aortic thrombosis (MAT) is a rare cause of ALI. While there is limited evidence on the use of bedside ultrasound for the detection of ALI or MAT, duplex ultrasound remains the standard in the diagnosis and ultimate medical decision-making in patients with acute and chronic limb ischemia. Point-of-care ultrasound may be used in the evaluation of patients with signs and symptoms of this disease entity. This is a case of a 79-year-old female with a complicated medical history, who presented with a pulseless right leg and abdominal tenderness. The patient quickly decompensated requiring intubation for airway protection. A post-intubation arterial blood gas (ABG) was unsuccessfully attempted in the right femoral artery, prompting an ultrasound-guided ABG. On B-mode ultrasound evaluation, echogenic material was visualized in the right common femoral artery without evidence of Doppler flow signal. Additionally, a partially obstructing echogenic material was also noted at the femoro-saphenous vein junction with only partial compressibility by compression sonography. A computed tomography angiography of the aorta was performed indicating extensive infrarenal aortic thrombosis. The patient expired despite the relatively prompt diagnosis, highlighting the importance of early identification of acute arterial occlusion.