Medial pterygoid muscle and stylomandibular ligament: the effects on postoperative stability.

The postoperative skeletal stability following surgical advancement of the mandible can be influenced by several factors. The effect of the medial pterygoid muscle and the stylomandibular ligament on the stability of results following surgical advancement has possibly been underestimated. In this retrospective study, the long-term postoperative skeletal stability following surgical advancement of the mandible in two groups of patients was studied and compared. In one group the medial pterygoid muscle and the stylomandibular ligament were stripped from the medial side of the angle of the mandible during the bilateral sagittal split osteotomy (BSSO) procedure while for the other group of patients these muscles and ligaments were left attached. The long term skeletal stability of the two groups was compared and the group that had the muscles and the ligaments stripped proved to be more stable than the other group.

Variations in the anatomical dimensions of the mandibular ramus and the presence of third molars: its effect on the sagittal split ramus osteotomy.

The authors undertook a prospective study to evaluate the influence that the anatomical dimensions of the ramus of the mandible and the presence of lower third molar teeth may have on the sagittal split ramus osteotomy. The anatomical dimensions measured included the width of the anterior mandibular ramus, the height of the corpus posterior to the second mandibular molar and the antero-posterior anatomical position of the lingual. The influence that these dimensions of the mandible may have on the successful splitting of the mandibular ramus was investigated. The effect that the presence of wisdom teeth had on the difficulty of the procedure was also investigated. This study found that, unlike the presence of third molars, there was no single anatomical measurement that contributed to the level of difficulty of the sagittal split osteotomy. For descriptive purposes the authors proposes a classification of the four typical patterns of unfavourable splits.

How reliable are odour assessments?

This paper will demonstrate the differences found in odour test results, when odour sampling is performed at the same sources by two different consultants. By examining two case studies, this paper will highlight that the difference between the results can be significant. Both studies are based on odour sampling programs determining the odour removal efficiency of odour control units installed at two different facilities: a pet food facility and an oil/grease recycling facility. The first study is based on odour measurements at the inlet and outlet of the unit installed by Applied Plasma Physics AS at the pet food facility. Odour assessments were performed by two separate consultants at the same time. The second study is based on testing of the odour removal effectiveness of two units: a scrubber and a biofilter at an oil/grease recycling facility. During this study two odour sampling programs were performed by two consultants at different times, but under the same process conditions. This paper will show how varying results can play a role in choosing the adequate odour control technologies. The final results suggest that although, an odour control unit may appear to be insufficient, it actually is successful at removing the odours.

Use of non-thermal plasma and UV-light for removal of odour from sludge treatment.

Non-thermal plasma (NTP) systems can be used for abatement of odour nuisances. Odour reductions are achieved by radical-initiated oxidation and dust collection in the plasma reactor. For some emissions a sequence of NTP followed by UV-light can improve the odour reduction further. This study was conducted to evaluate the efficiency of NTP technology combined with UV-light towards odour emissions from sludge treatment. Air from a pilot sludge dryer was treated with a pilot NTP and a UV unit. The effect of using an acid scrubber upstream the NTP system was also tested. Thermal desorption gas chromatography and mass spectrometry (TD-GC/MS) was used to analyse samples taken from the inlet and the outlet of the NTP system. The TD-GC/MS used was also equipped with a sniffing port that made it possible to record odour-active compounds eluting from the column. Relative amounts of odour-active compounds in the inlet and the outlet flow from the NTP system were compared. Bag samples from inlet and outlet were also separately analysed by an external lab and by two operators using a one-man olfactometer, a modified NasalRanger(TM). These results indicated a significant odour removal efficiency of 70-90% depending on the settings and combinations of abatement equipment.

X-Ray induced radiation damage in taurine: a combined X-ray diffraction and Raman study.

The impact of X-radiation on crystalline taurine has been investigated by time resolved synchrotron X-ray powder and single crystal diffraction and Raman spectroscopy. Multiple data sets have been collected at 120 and 296 K. All the observed effects of radiation, i.e. broadening and shifts of Raman and diffraction lines, a dose dependent irreversible increase in the atomic displacement parameters (ADPs) as well as in one of the unit-cell axes, and an apparent enhancement of electron density in the SO(3) group can be tentatively attributed to primary radical formation predominantly involving the SO(3) group. In secondary reactions molecular species that are distinct from taurine are created in minute quantities, thereby introducing local departure from crystalline order, i.e. enhanced static disorder and a build-up of local strain. Our study provides evidence for ascribing the linear increase in ADPs as well as the expansion of the c axis to the accumulation of foreign species in the crystal, and not to a thermal effect. Once initiated, this process appears to continue also without radiation, however, then at a much reduced rate.

HPLC combined with multiple mass spectrometry (MSn): an alternative for the structure elucidation of compounds and artefacts found in smog chamber samples.

Ion trap multiple mass spectrometry combined with high-performance liquid chromatography (online HPLC-MSn) was used to identify carbonyl compounds and artefacts found in air samples of 2-3 L taken during the OH-radical reaction study of cis-3-acetyl-2,2-dimethylcyclobutylethanal (pinonal) or cis-3-acetyl-2,2-dimethylcyclobutylcarbaldehyde (nor-pinonal) in a smog chamber. Carbonyls were transformed into 2,4-dinitrophenylhydrazones. Detection of low picogram quantities was possible. Twenty-eight compounds could be identified based on the presence of structure characteristic fragments, a developed fragmentation scheme, comparison of retention times and a library of MSn spectra of selected carbonyls. Furthermore, the additional elucidation of the sub-structures of sixteen unknowns was possible. Details about the structure elucidation procedure and the formation of the observed fragments are presented.