Analysis of Models Predicting Morphology Transitions in Reactive Twin-Screw Extrusion of Bio-Based Polyester/Polyamide Blends

Immiscible PLA/PA11 of 80/20 and 50/50 wt% were compatibilized through addition of p-toluenesulfonic acid (TsOH) catalyst in reactive ultra-high speed twin-screw extrusion. Two mixing screw designs were compared for their ability to disperse the PA11 droplets in the PLA matrix as a function of screw speed up to 2000 rpm. The size and polydispersity of droplets of dispersed PA11 decreased when a high shear (HS) screw was used, whereas broad droplet size distribution was produced in the low shear (LS) screw. Two models predicting the droplet size dependence on shear rate, viscosity ratio and interfacial tension were fit to the experimental data. The Serpe model including volume fraction effects produced a better fit compared to the Wu model, which does not include volume fraction effects. Mechanical testing indicated that the compatibility of PLA/PA11 blends was improved through addition of TsOH catalyst for 50/50 wt% blends due to ester – amide exchange reactions at the interfaces in the immiscible PLA and PA11 phases. The enhancement of ductility was greater after processing with the LS screw configuration than the HS screw configuration. The inferior properties after high shear mixing were likely due to molecular weight degradation during processing. While the aggressive shear in the HS screw design resulted in fine dispersion, care should be taken to minimize degradation, especially for shear sensitive polymers.

Application of cone beam computed tomography in oral and maxillofacial surgery

In the past decade, the utility of cone beam computed tomography (CBCT) images in oral and maxillofacial surgery has seen continuous increase. However, CBCT images are not always able to replace other imaging modalities. Based on the current published knowledge, this paper discusses advantages and limitations of CBCT images in the diagnosis and surgical planning of dentoalveolar procedures, odontogenic cysts, benign and malignant tumours, inflammatory changes, orthognathic surgery, maxillofacial trauma, sinus disorders, and systemic and osseous conditions that manifest in the maxillofacial area. This paper also suggests alternative imaging modalities when CBCT images are not adequate for surgical planning.

Pharyngeal airway space changes after counterclockwise rotation of the maxillomandibular complex

The purpose of this study was to evaluate the effects of double-jaw surgery with counterclockwise rotation of the maxillomandibular complex on the pharyngeal airway space and velopharyngeal anatomy in patients with high occlusal plane facial morphology. Fifty patients (22 men, 28 women) with high occlusal plane facial morphology underwent double-jaw surgery with counterclockwise rotation of the maxillomandibular complex. The patients were divided into 2 groups: group 1, 30 patients (8 men, 22 women) who underwent maxillary and mandibular advancement and group 2, 20 patients (14 men, 6 women) who underwent maxillary advancement and mandibular setback. Presurgery and postsurgery lateral cephalometric radiographs were analyzed to correlate changes in pharyngeal airway space dimensions and velopharyngeal anatomy with maxillary and mandibular positional changes. The calibration showed a more than 0.94 correlation for both intra- and interoperator error. The average follow-up time was 29.6 months in group 1 and 22.2 months in group 2. Mean maxillary surgical change at point A was 4.15 mm in group 1 and 2.5 mm in group 2. Mean mandibular surgical change at the genial tubercles was 7.5 mm in group 1 and -4.95 mm in group 2. After surgery, group 1 patients had an increase in pharyngeal airway space of 47% at the soft palate and 76% at the base of the tongue relative to the amount of mandibular advancement. Group 2 patients had a decrease in pharyngeal airway space of 47% at the soft palate and 65% at the base of the tongue relative to the amount of mandibular setback. Double-jaw surgery with counterclockwise rotation of the maxillomandibular complex significantly affects the pharyngeal airway space and velopharyngeal anatomy in patients with high occlusal plane facial morphology, with both mandibular advancement and setback.

The organ maintained human sebaceous gland

<i>Objective:</i> Antiphospholipid syndrome (APS) or Hughes syndrome is a frequently seen condition in Kuwait that is characterised by the presence of significant titres of a variety of antiphospholipid antibodies (aPL). The main clinical features of this syndrome include thrombosis (both venous and arterial), recurrent fetal wastage and thrombocytopenia. The aim of the present study was to find out the antibodies with a high predictive value for the diagnosis of APS. <i>Methodology:</i> The study included a total of 38 subjects. Nine of them were patients with proven primary APS, 10 with secondary APS and 19 were patients (controls) with weak clinical evidence of APS. After a complete clinical examination and routine investigations, the following categories of aPL were estimated by standard laboratory techniques: anticardiolipin antibodies of IgG and IgM isotypes (GPL and MPL, respectively), anti-β₂-glycoprotein-I antibodies (anti-β₂-GPI) of IgG and IgM isotypes and activated partial thromboplastin time as a surrogate for lupus anticoagulant (LAC). The tests were considered positive if the titres were more than a standard cut-off value provided by the manufacturer of the kits, and in one instance, the normal range was established in our laboratory (LAC). <i>Results:</i> The highest sensitivity (78.9%) and diagnostic accuracy (71.1%) were obtained by the estimation of GPL. However, excellent specificity (100%) and positive predictive value (100%) with almost as good a diagnostic accuracy (68.4%) were also obtained with anti-β₂-GPI of IgG isotype. All the other tests performed poorly when compared with these two. There was no difference in the performance of these tests between primary and secondary APS. <i>Conclusion:</i> Of the various aPL estimated, GPL and anti-β₂-GPI of IgG isotype were statistically sensitive and specific investigations for confirming the diagnosis of APS.

New reference reagent for the quality assurance of anti-D antibody detection

A UK BTS-NIBSC freeze-dried anti-D preparation has been prepared and used to monitor the performance of routine antibody detection tests and of the test operators. With the day-to-day use of this preparation, adverse changes in test performance and in test operator may be detected and appropriate action taken before the effect becomes significant. Two dilutions of this preparation have been defined, one which should be detected unequivocally in every test; the other, more dilute, may not be detected in every test but is used to monitor changes in performance. Experience with the use of this preparation is reported from three test centres undertaking routine antibody detection tests. By monitoring results over a series of working days, significant differences were noted in operator performance within one test centre, as was a reduced sensitivity of a given test system within one test centre compared with the same system in the other test centres. These differences were detected only by monitoring the results obtained with this preparation.

Australian trial of topical minoxidil and placebo in early male pattern baldness

One hundred and sixty nine men with early male pattern baldness (androgenic alopecia) were treated in a random, double-blind fashion with either 2% minoxidil solution or placebo vehicle for 24 weeks, one ml applied twice daily. After 24 weeks all patients received the active solution until week 48. After 24 weeks the minoxidil treated patients had increased their non-vellus hair counts significantly more than the placebo treated group; means were 37.6 and 8.8 hairs per reference area, 95% C.I. for difference = 10.85 to 60.75. The rate of non-vellus hair regrowth was also greater among minoxidil treated patients than placebo treated patients. Nine (12.5%) evaluable minoxidil treated patients compared with 2 (2.7%) evaluable placebo treated patients reported moderate or dense hair regrowth at week 24. Minimal regrowth was reported by 18 (25%) active group and 15 (20%) placebo group patients. The investigators considered that 3 (2%) of the minoxidil group and none of the placebo group had moderate hair regrowth and that none had dense regrowth. After 48 weeks treatment 28 (23%) patients considered that they had moderate hair regrowth and the investigators considered that 14 (12%) patients had moderate regrowth. None had dense growth. No serious adverse reactions or deaths were reported. Minoxidil solution appeared to be an efficacious and safe treatment for early androgenic alopecia.

Quantitation of antibody binding to erythrocytes in LISS

The amount of antibody bound to cells in a low ionic strength solution (LISS) has been quantitated for several antibodies including anti-D, anti-c, anti-Kell, anti-Fya, and anti-Jka. With the exception of the Kell antibodies there was an enhancement of the rate of antibody uptake in LISS. For Rh antibodies the amount bound after a 5-min LISS incubation is comparable to that bound after 45 min in saline. For Kell antibodies a smaller amount was bound in LISS than in saline. The effect of the ratio of serum to cells was also studied, and with several antibodies there was an increase in the amount of antibody bound with a higher serum to cell ratio irrespective of suspending medium. For Kell antibodies this ratio appears to be of greater importance than the ionic strength for antibody detection. A modification to the LISS method to increase the serum to cell ratio is, therefore, presented.