Magnetic diagnostic suite of the C-2W field-reversed configuration experiment.

A fundamental component of any magnetically confined fusion experiment is a firm understanding of the magnetic field. The increased complexity of the C-2W machine warrants an equally enhanced diagnostic capability. C-2W is outfitted with over 700 magnetic field probes of various types. They are both internal and external to the vacuum vessel. Inside, a linear array of innovative in-vacuum annular flux loop/B-dot combination probes provide information about plasma shape, size, pressure, energy, temperature, and trapped flux when coupled with established theoretical interpretations. A linear array of B-dot probes complement the azimuthally averaged measurements. A Mirnov array of 64 3D probes, with both low and high frequency resolution, detail plasma motion and MHD modal content via singular value decomposition analysis. Internal Rogowski probes measure axial currents flowing in the plasma jet. Outside, every feed-through for an internal probe has an external axial field probe. There are many external loops that measure the plasma formation dynamics and the total external magnetic flux. The external measurements are primarily used to characterize eddy currents in the vessel during a plasma shot. Details of these probes and the data derived from their signals are described.

Characterization and calibration of the Thomson scattering diagnostic suite for the C-2W field-reversed configuration experiment.

The new C-2W Thomson scattering (TS) diagnostic consists of two individual subsystems for monitoring electron temperature (Te) and density (ne): one system in the central region is currently operational, and the second system is being commissioned to monitor the open field line region. Validating the performance of the TS's custom designed system components and unique calibration of the detection system and diagnostic as a whole is crucial to obtaining high precision Te and ne profiles of C-2W's plasma. The major components include a diode-pumped Nd:YAG laser which produces 35 pulses at up to 20 kHz, uniquely designed collection lenses with a fast numerical aperture, and uniquely designed polychromators with filters sets to optimize a Te ranging from 10 eV to 2 keV. This paper describes the design principles and techniques used to characterize the main components of the TS diagnostic on C-2W, as well as the results of Rayleigh scattering calibrations performed for the whole system response.

Development of a three-wave far-infrared laser interferometry and polarimetry diagnostic system for the C-2W field-reversed configuration plasmas.

Great advancements in modern field-reversed configuration (FRC) experiments motivated the development of a 14-chord three-wave far infrared (FIR) laser interferometry and polarimetry diagnostic system, which can provide simultaneous high temporal resolution measurements of density and Faraday rotation profiles with high accuracy. The unique challenges facing FIR diagnostics in high beta FRC plasmas are the extremely small (<0.5°) Faraday rotation angles, and severe laser beam refraction effects due to high density gradient and choice of long wavelength. The diagnostic system design and development are described with methods to overcome the challenges, and initial experimental data are also presented.

Thomson scattering systems on C-2W field-reversed configuration plasma experiment.

TAE Technologies' newly constructed C-2W experiment aims to improve the ion and electron temperatures in a sustained field-reversed configuration plasma. A suite of Thomson scattering systems has been designed and constructed for electron temperature and density profile measurements. The systems are designed for electron densities of 1 × 1012 cm-3 to 2 × 1014 cm-3 and temperature ranges from 10 eV to 2 keV. The central system will provide profile measurements of Te and ne at 16 radial locations from r = -9 cm to r = 64 cm with a temporal resolution of 20 kHz for 4 pulses or 1 kHz for 30 pulses. The jet system will provide profile measurements of Te and ne at 5 radial locations in the open field region from r = -5 cm to r = 15 cm with a temporal resolution of 100 Hz. The central system and its components have been characterized, calibrated, installed, and commissioned. A maximum-likelihood algorithm has been applied for data processing and analysis.

[A single effective way to reduce post-thyroidectomy discomfort: a clinical trial]. / Un metodo semplice ed efficace per ridure il discomfort dopo tiroidectomia: un trial clinico.

AIM: Nausea, with or without vomiting (postoperative nausea and vomiting, PONV), occurs up to 60-76% after thyroidectomy and other head and neck surgeries. Due to the fact that patients typically have only mild-to-moderate pain after thyroid or parathyroid surgery, PONV might be the main source of discomfort, and it may be perceived as the most unpleasant aspect of postoperative recovery. This study aims to assess the effects of a preoperative single dose of 8 mg dexamethasone on the nausea, vomiting, pain, and subjective vocal function after thyroidectomy in patients undergoing surgery for benign disease. METHODS: Seventy patients operated on for thyroidectomy were randomized in two groups: Group A, 8 mg/2 mL of dexamethasone administered in 100 mL of physiologic saline given intravenously (i.v.) 20 minutes before the induction of anesthesia; group B, 2 mL NaCl 0.9% in 100 mL of physiologic saline. Postoperative therapy has been standardized. PONV have been evaluated with a scale of 4, degrees (0-3), pain by a Visual Analog Scale (0-100) and subjective vocal function by a Visual Analog Scale (0-100) at 8, 24, 32 and 48 hours after surgery. RESULTS: The severity of nausea was less in patients of group A (P=0.0001); Dexamethasone patients reported significantly less pain (P=0.008); no differences were noted about the subjective voice analysis (P=0.693). No steroid-related complications occurred. CONCLUSION: Dexamethasone 8 mg i.v. is a safe and effective method to reduce PONV and pain after thyroid resection and we advise its routine use.

[A new effective method to reduce pain after laparoscopic cholecystectomy]. / Un nuovo efficace sistema per ridurre il dolore dopo videolaparocolecistectomia.

BACKGROUND: The primary aim of this randomized controlled prospective study (www.clinicaltrials.gov NCT00599144) was assessing effectiveness on pain control after videolaparoscopic cholecystectomy (VLC) of 0.5% Bupivacaine-soaked sheet of regenerated oxidized cellulose positioned in the gallbladder bed. PATIENTS AND METHODS: We randomized in three equal groups 45 patients that underwent elective videolaparoscopic cholecystectomy: group A - Bupivacaine-soaked sheet of regenerated oxidized cellulose positioned in the gallbladder bed; group B - Bupivacaine infiltrated in the muscular fasciae of the trocars' seat; group C - control group, not using local anesthetic. Six and 24 hours after the intervention we recorded the type of the pain and its intensity, using a visual analog scale (VAS). RESULTS: We observed no statistically significant difference in pain intensity. Considering the type of pain, 55,56% of patients referred visceral pain, 62,22% parietal pain and 44,44% shoulder pain. Group A shows, at both endpoints, a statistically significant reduction (p < 0.05) of visceral and shoulder pain versus other groups. Moreover, the use of a local anesthetic significantly reduces the use of post-operative pain drugs, both for group A and B. CONCLUSION: A Bupivacaine-soaked sheet of regenerated oxidized cellulose positioned in the gallbladder bed post-VLC is safe and not economically demanding, and can give advantages in increasing post-operative comfort.

Voltage breakdown follower avoids hard thermal constraints in a Geiger mode avalanche photodiode.

A novel approach to single-photon detection by means of an avalanche photodiode is described and preliminary results obtained by implementation of a prototype are reported. The electronic circuit (breakdown voltage follower) avoids the use of complex temperature controls typically used with these devices, thus reducing system complexity and cost. Data obtained without any thermoregulation show the same behavior with respect to systems thermoregulated to within a few hundredths of a degree celsius.

[Hazards of thrombolysis. A clinical case]. / I pericoli della trombolisi. Caso clinico.

Thrombolytic therapy has led to a reduction in early and late mortality in myocardial infarction but it is not without its dangers. Two cases are reported in which it was adopted inadvisedly considering that later pathologies other than acute myocardial infarction were demonstrated. A less aggressive attitude is advised for emergency thrombolysis (pending the arrival of more effective, safer drugs) in the more peripheral centres where possible complications may be more difficult to handle.

To assess the efficacy of prophylaxis in digestive tract surgery using a predictive model of complication risk.

One hundred and ninety-one patients, all candidates for major clean-contaminated surgery, were classified according to the risk of developing postoperative wound infection, using clinical and nutritional factors. A widely validated nutritional assessment model, the Prognostic Nutritional Index (PNI), was used preoperatively to evaluate the risk and probability of post-operative septic complications. Based on the predicted outcome, patients were assigned to either a poor or a good risk group for statistical comparison. A prospective, double-blind, randomized trial was performed to compare the effectiveness of the monocyclic beta-lactam, aztreonam, with gentamicin for short-term perioperative prophylaxis. In the poor risk group (PNI greater than 40), aztreonam prophylaxis significantly reduced postoperative septic complications (p less than 0.05). The use of an objective scoring system to assess the risk of postoperative sepsis is recommended for future studies on antibiotic prophylaxis as it offers a realistic assessment basis.