Depositions of nitrogen on NiTi instruments

This study was designed to obtain nitrogen-rich layers on the surfaces of endodontic files made of nickel-titanium (NiTi) alloy by chemical vapor deposition. Experimental samples (GT rotary instruments) were deposited by using two different methods. The first one was based on the reaction of wet NH3 with NiTi under high temperatures (300 degrees C). The second technique is a typical MOCVD (metal organic chemical vapor deposition) procedure that uses Ti(Et2N)4 as a titanium and nitrogen precursor. Control samples were not exposed to any process. The chemical composition of the surface layers of each sample was determined by means of X-ray photoelectron spectroscopy and X-ray diffraction measurements. The experimental instruments showed surface chemical composition that was different from that seen in the control group; samples treated with gaseous NH3 showed a surface nitrogen/titanium (N/Ti) ratio = 0.9; MOCVD instruments showed a surface N/Ti ratio of 2; control samples showed a N/Ti ratio = 0.2; MOCVD of nitrogen ion of nickel-titanium files produced a higher concentration of nitrogen on the surface.     

An unusual anomaly of the radial artery with potential significance to the forearm free flap. Case report.

INTRODUCTION: The radial forearm free flap has become the favourite transplant for microsurgical repair of small-to-medium sized soft tissue defects of the oral cavity. This flap derives its blood supply from perforators of the radial artery. As the radial forearm flap gains ever more popularity, it is likely that anomalous forearm vascular patterns will be encountered by more surgeons. PURPOSE: In this paper, a rare anomaly found in a patient during flap elevation is described. This 63-year-old male had a squamous cell carcinoma of the floor of the mouth and a radial forearm free flap was harvested to repair the defect. During this procedure an aberrant duplication of the radial artery was found which could have significance in harvesting such a flap in other patients. CONCLUSION: There are anomalies of the radial artery that may jeopardize the vascular supply to the radial forearm free flap. Surgeons performing this flap must be aware of the most common variants of the vascular anatomy of the forearm.     

Substantia nigra in Parkinson’s disease: a multimodal MRI comparison between early and advanced stages of the disease

This study focused on the substantia nigra (SN) in Parkinson’s disease (PD). We measured its area and volume, mean diffusivity (MD), fractional anisotropy (FA) and iron concentration in early and late PD and correlated the values with clinical scores. Twenty-two early PD (EPD), 20 late PD (LPD) and 20 healthy subjects (age 64.7 ± 4.9, 60.5 ± 6.1, and 61 ± 7.2 years, respectively) underwent 1.5 T MR imaging with double-TI-IR T1-weighted, T2*-weighted and diffusion tensor imaging scans. Relative SN area, MD, FA and R2* were measured in ROIs traced on SN. Correlation with Unified Parkinson Disease Rating Scale (UPDRS) scores was assessed. In LPD, the SN area was significantly reduced with respect to EPD (p = 0.04) and control subjects (p < 0.001). In EPD, the SN area was also significantly smaller than in controls (p = 0.006). Similarly, the SN volume significantly differed between LPD and controls (p = 0.001) and between EPD and LPD (p = 0.049), while no significant differences were found between controls and EPD. Both SN area (r = 0.47, p = 0.004) and volume (r = 0.46, p = 0.005) correlated with UPDRS scores. At 1.5 T, SN morphological measurements were sensitive to early PD changes and able to track the disease progression, while MD and FA measures and relaxometry did not provide significant results.     

Back to the Future with Phenotypic Screening

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