Validation of a Database of Formation Enthalpies and of Mid-Level Model Chemistries.

In order to test new procedures for the calculation of basic molecular properties, a properly validated database and computational method appropriate to the range of species at hand is essential. Here formation enthalpies of chemical species CmHnNpOq from their constituent atoms are computed by midlevel composite model chemistries in order to check the contents of the best established and most accurate database, ATcT. Once discrepancies are identified alternative independent procedures and/or higher level model chemistries, which include CCSDT(Q) calculations, are employed to resolve the problems. Shortcomings of the midlevel methods used are signaled where these occur. In addition a more visual statistical analysis than is usual is presented which highlights the outliers and identifies the bias of each method together with associated error bars and the 95% limits of agreement and its error bars.

Neuromas as the cause of pain in the residual limbs of amputees. An ultrasound study.

AIM: To explore the morphology of neuromas and to determine the differences, if any, between asymptomatic and symptomatic neuromas using ultrasound. MATERIALS AND METHODS: Eighty patients with symptomatic neuromas were included in this retrospective review. High-resolution ultrasound examination was performed. Transducer pressure allowed real-time analysis of both symptomatic and asymptomatic neuromas. Quantifiable assessment of pain by the patient assigned a pain score of 0, 1, 2, or 3, to each neuroma. RESULTS: One hundred and fifty-nine neuromas were identified in total. Fifty-three neuromas were asymptomatic (pain score=0), very severe pain was recorded in 54 (pain score=3), 16 neuromas were mildly painful (pain score=1) and 36 were moderately painful (pain score=2). The average number of neuromas per patient was 1.98, and the average number of symptomatic neuromas per patient was 1.3. There was no correlation between pain score and patient age, neuroma volume, amputation type, and time since amputation. CONCLUSIONS: High-resolution ultrasound can distinguish between asymptomatic and symptomatic neuromas. Patient age, time since amputation, the type of amputation, and the neuroma volume were not related to the presence of pain.

The ultrasonically activated scalpel versus bipolar diathermy for tonsillectomy: a prospective, randomized trial.

Among patients undergoing tonsillectomy, the ultrasonic scalpel has been reported to lead to less intraoperative blood loss than cold dissection, and less postoperative pain and faster recovery than monopolar electrocautery. However, the ultrasonic scalpel has not been compared with bipolar diathermy. The present study was a prospective, randomized, single-blind trial, comparing these two techniques with respect to postoperative pain. Twenty-one adults underwent tonsillectomy on one side using the ultrasonic scalpel, and on the other using bipolar diathermy. Pain scores were obtained on postoperative days 1, 2, 7 and week 3. There was no difference between the two treatments at any of the time points (P = 0.6047, 0.4018, 0.6047 and 0.5000, respectively). Inability to control bleeding with the ultrasonic scalpel resulted in the rescue use of an alternative technique of haemostasis in 14 cases. We conclude that the use of the ultrasonic scalpel in adult tonsillectomy is likely to be limited by its substantial costs and difficulties with haemostasis.

Effect of tumour thickness and other factors on the risk of regional disease and treatment of the N0 neck in early oral squamous carcinoma.

A high occult metastatic rate and a high regional recurrence rate are reported among patients with early oral squamous carcinoma; however, considerable controversy exists regarding the merits of elective neck dissection in this group. The purpose of the present study was to examine the influence of various histological factors on the risk of occult neck disease, neck conversion and recurrence among 63 patients with stage I and II oral cancer. Tumour thickness (P = 0.0175) and size (P = 0.023) were both significantly predictive of outcome. Among tumours of a given thickness, those with infiltrative margins also showed a tendency towards a poorer outcome; however, this was not significant (P = 0.0768). Patients undergoing elective neck dissection with pathological evidence of cervical metastases or with subsequent neck recurrence had a better 3-year survival (55%) than those developing neck conversion after primary neck observation (20%). Our data would suggest considering tumours greater than 5 mm in thickness or with infiltrative margins as potential candidates for elective neck treatment.

Sequelae of otitis media with effusion among children with cleft lip and/or cleft palate.

Otitis media with effusion (OME) is common among children with cleft palate, and may lead to such long-term consequences as hearing loss, tympanic membrane retraction, and chronic otitis media (COM). In total, 104 children with cleft lip and/or palate treated for OME at our institution were reviewed. Mean duration of follow-up was 6.9 years, and mean age at latest follow-up was 9.6 years. The incidence of COM was 19%, and the incidence of cholesteatoma was 1.9%. Ears showing such long-term sequelae of OME as hearing loss, tympanic membrane retraction, and chronic otitis media, were noted to have undergone a significantly greater number of ventilation tube insertions than ears not showing these sequalae. Our findings would suggest that a conservative approach to the management of OME in children with cleft palate is more likely to be beneficial in the long term.