In situ size sorting in CVD synthesis of Si microspheres

Silicon microspheres produced in gas-phase by hot-wall CVD offer unique quality in terms of sphericity, surface smoothness, and size. However, the spheres produced are polydisperse in size, which typically range from 0.5 μm to 5 μm. In this work we show through experiments and calculations that thermophoretic forces arising from strong temperature gradients inside the reactor volume effectively sort the particles in size along the reactor. These temperature gradients are shown to be produced by a convective gas flow. The results prove that it is possible to select the particle size by collecting them in a particular reactor region, opening new possibilities towards the production by CVD of size-controlled high-quality silicon microspheres.

Global oral health inequalities in incidence and outcomes for oral cancer: causes and solutions

The mouth and oropharynx are among the ten most common sites affected by cancer worldwide, but global incidence varies widely. Five-year survival rates exceed 50% in only the best treatment centers. Causes are predominantly lifestyle-related: Tobacco, areca nut, alcohol, poor diet, viral infections, and pollution are all important etiological factors. Oral cancer is a disease of the poor and dispossessed, and reducing social inequalities requires national policies co-ordinated with wider health and social initiatives - the common risk factor approach: control of the environment; safe water; adequate food; public and professional education about early signs and symptoms; early diagnosis and intervention; evidence-based treatments appropriate to available resources; and thoughtful rehabilitation and palliative care. Reductions in inequalities, both within and between countries, are more likely to accrue from the application of existing knowledge in a whole-of-society approach. Basic research aimed at determining individual predisposition and acquired genetic determinants of carcinogenesis and tumor progression, thus allowing for targeted therapies, should be pursued opportunistically.

Bilateral radical neck dissection: results in 193 cases

BACKGROUND AND OBJECTIVES

Indications of simultaneous bilateral radical neck dissection remains controversial. The main objectives of this analysis were to study: a) the frequency of postoperative complications, b) the patterns of metastatic lymph nodes in the surgical specimen, c) the predictive factors of neck recurrences, d) the prognostic factors related to overall survival.

METHODS

A retrospective review of results in 193 consecutive patients submitted to a simultaneous bilateral radical neck dissection from 1960-1990.

RESULTS

Postoperative complications occurred in 60.8% of the cases. The most frequent ones were: fistula, wound infection, flap dehiscence and necrosis. There were four postoperative deaths (2.7%). The lymph nodes most frequently involved were of the upper jugular and upper accessory groups. Only patients with lip and paranasal sinus tumors never presented metastatic nodes at Levels IV and V. Tumor recurrences were more common at the ipsilateral neck (13.5%) or at distant sites (12.4%). The predictive factors of neck recurrences were: age, N stage, ipsilateral metastasis at Level II, and contralateral metastasis at Levels II and IV. The overall 5-year survival rates for the two age groups, that is, younger than 40 and older than 40 years of age, were respectively, of 8.5% and 35.6% (P = 0.0296). There were no survivals among the group of patients with neck lymph nodes staged as N3 or Nx. The overall 5-year survival rates were significantly influenced by contralateral metastatic lymph nodes at any level. The results of multivariate analysis using the Cox regression technique, showed that Level II ipsilateral metastatic lymph nodes, Levels II and IV contralateral metastatic lymph nodes, and age were the independent predictors of the risk of death.

CONCLUSIONS

This study demonstrates that simultaneous bilateral neck dissection has a high morbidity and should be contraindicated as an elective procedure. Further studies with selective neck dissections are warranted.

Balance of mass, momentum, and energy in splintering central collisions for 40Ar up to 115 MeV /Nucleon

For central collisions of (17-115)A MeV 40Ar+Cu, Ag, Au, an overall balance is determined for the average mass, energy, and longitudinal momentum. Light charged particles and fragments are separated into forward-focused and isotropic components in the frame of the heaviest fragment. Energy removal by the isotropic component reaches 1-2 GeV. For such high deposition energies, statistical multifragmentation models predict much more extensive nuclear disassembly than is observed.

Argyrophilic nucleolar organizer regions staining is useful in predicting recurrence-free interval in oral tongue and floor of mouth squamous cell carcinoma

BACKGROUND

Argyrophilic nucleolar organizer regions (AgNORs) represent a tissue marker of cell proliferative activity. The purpose of this study was to assess the prognostic value of AgNORs expression in oral squamous cell carcinoma (SCC).

METHODS

The AgNORs area/nucleus was studied in paraffin sections by means of digital image analysis in 43 cases of stage II oral tongue and floor of the mouth SCC.

RESULTS

Time free of disease was considered a dependent variable of a binary indicator of AgNORs expression (7.77 microns2/nucleus as a cut-off point). High AgNORs level was associated with a statistically significant negative effect on recurrence-free interval of disease in a Cox proportional hazards models controlled for occult lymph node metastasis, involvement of the surgical margins, thickness of the lesion, and vascular invasion.

CONCLUSIONS

The AgNORs area increased the capability of predicting which patients have a high risk of recurrence of cancer, and its evaluation may provide useful information for the therapeutic approach to the oral tongue and floor of the mouth SCC.

Effect of cyclical therapy with phosphorus and etidronate on axial bone mineral density in postmenopausal osteoporotic women

Forty seven women with postmenopausal osteoporosis and at least one but no more than four vertebral compression fractures received sequential and cyclical therapy with phosphorus and etidronate (p/etid). During the same 2-year period of observation, three other groups of patients received either sodium fluoride (n = 12), estrogen replacement therapy (n = 12), or vitamin D and calcium (Ca++) alone (n = 15). Axial bone mineral density (BMD) was measured by means of dual-photon absorptiometry. Lateral thoracic and lumbar spine radiographs were taken to assess fractures. Bone mineral density increased from baseline during p/etid therapy: Mean 15.7 +/- 1.6% (SD) (P less than 0.001). During the same time, the patients in the sodium fluoride group showed a comparable increase in their BMD from baseline: mean 15.7 +/- 1.1% (P less than 0.001). During the first year of therapy, patients in the estrogen replacement group had an increase in their BMD from baseline: mean: 4.6% +/- 1.1% (P less than 0.05). No change in BMD was seen in the control group that received vitamin D and Ca++ alone. No patient who received p/etid, sodium fluoride, or estrogen replacement therapy had any new vertebral compression fractures or height loss, whereas in the control group that received vitamin D and Ca++ alone 6 out of 15 had height loss and at least one new vertebral fracture (P less than 0.01). p/etid therapy increases BMD in women with postmenopausal osteoporosis comparable to sodium fluoride but without side effects or toxicity and stabilizes vertebral compression fractures.

Conservation surgery for radiation-failure carcinoma of the glottic larynx

A consecutive series of 28 patients treated by conservation surgery of the larynx for radiation-failure, recurrent rT1 and T2 (postradiotherapy staging) glottic squamous cell carcinoma treated at Memorial Sloan-Kettering Cancer Center from 1966 to 1983 is reviewed. The majority of patients were men with the age ranging from 46 to 76 years. The disease-free interval ranged from 0 to 113 months (median, 8.5 months). The stage at presentation was rT1 in 25 patients and rT2 in 3 patients. Surgery consisted of cordectomy (7 patients), hemilaryngectomy (18), and extended hemilaryngectomy (3). There was no operative mortality. Local recurrence developed in 8 patients (28.5%), cervical metastasis in 2, and distant metastasis in 1. Only 3 patients were salvaged by further treatment. The rate of local control was influenced by positive surgical margins. Overall, voice preservation was achieved in 75% of patients. The ultimate local control was 82.1% during a follow-up period that ranged from 1.3 to 16.7 years (median, 6.3 years). The actuarial survival at 5 and 10 years was 73% and 71% following conservation surgery of the larynx.