462 research outputs found
Hard macrocells for DC/DC converter in automotive embedded mechatronic systems
A novel configurable DC/DC converter architecture, to be integrated as hard macrocell in automotive embedded systems, is proposed in the paper. It aims at realizing an intelligent voltage regulator. With respect to the state of the art, the challenge is the integration into an automotive-qualified chip of several advanced features like dithering of switching frequency, nested control loops with both current and voltage feedback, asynchronous hysteretic control for low power mode, slope control of the power FET gate driver, and diagnostic block against out-of-range current or voltage or temperature conditions. Moreover, the converter macrocell can be connected to the in-vehicle digital network, exchanging with the main vehicle control unit status/diagnostic flags and commands. The proposed design can be configured to work both in step-up and step-down modes, to face a very wide operating input voltage range from 2.5 to 60 V and absolute range from −0.3 to 70 V. The main target is regulating all voltages required in the emerging hybrid/electric vehicles where, besides the conventional 12 V DC bus, also a 48 V DC bus is present. The proposed design supports also digital configurability of the output regulated voltage, through a programmable divider, and of the coefficients of the proportional-integrative controller inside the nested control loops. Fabricated in 0.35 μm CMOS technology, experimental measurements prove that the IC can operate in harsh automotive environments since it meets stringent requirements in terms of electrostatic discharge (ESD) protection, operating temperature range, out-of-range current, or voltage condition
Orthodontics and obstructive sleep apnea in children
Children who suffer from respiratory problems and obstructive sleep apnea (OSA)
commonly exhibit disturbances of craniofacial morphology. A significant number
have nasal obstruction associated with a narrow maxilla; maxillary constriction
may increase nasal resistance and alter the tongue posture, leading to narrowing
of the retroglossal airway and OSA. Sixty children with a case history of oral
breathing, snoring, and night time apneas were studied. An orthognathodontic
investigation was performed using radiographs that included not only the usual
examinations (posteroanterior cephalographs and intraoral radiographs) but also
computed tomographic scans. This article discusses the materials and methods and
the results of this study
Bis(monoacylglycero)phosphate Forms Stable Small Lamellar Vesicle Structures: Insights into Vesicular Body Formation in Endosomes
AbstractBis(monoacylglycero)phosphate (BMP) is an unusually shaped lipid found in relatively high percentage in the late endosome. Here, we report the characterization of the morphology and molecular organization of dioleoyl-BMP (DOBMP) with dynamic light scattering, transmission electron microscopy, nuclear magnetic resonance (NMR) spectroscopy, and electron paramagnetic resonance spectroscopy. The morphology of hydrated DOBMP dispersions varies with pH and ionic strength, and DOBMP vesicles are significantly smaller in diameter than phosphatidylcholine dispersions. At neutral pH, DOBMP forms highly structured, clustered dispersions 500 nm in size. On the other hand, at acidic pH, spherically shaped vesicles are formed. NMR and spin-labeled electron paramagnetic resonance demonstrate that DOBMP forms a lamellar mesophase with acyl-chain packing similar to that of other unsaturated phospholipids. 31P NMR reveals an orientation of the phosphate group in DOBMP that differs significantly from that of other phospholipids. These macroscopic and microscopic structural characterizations suggest that the biosynthesis of BMP on the inner luminal membrane of maturing endosomes may possibly produce budded vesicles high in BMP content, which form small vesicular structures stabilized by the physical properties of the BMP lipid
Characterization of adenomas and metastases in the adrenals: comparison between spin-echo sequences and Gd-DTPA enhanced dynamic studies.
Treatment of intermetatarsal Morton's neuroma with alcohol injection under US guide: 10-month follow-up
Mortons neuroma (MN) is a frequent cause of metatarsalgia. The aim of our study was to evaluate the efficacy of neuroma alcohol-sclerosing therapy (NAST) under US guide in MN after a 10-month follow-up. Forty intermetatarsal neuromas underwent alcohol-sclerosing therapy after sonographic evaluation of their dimensions and echotexture. After subcutaneous anesthesia, a sclerosing solution composed of anesthetic (carbocaine-adrenaline 70%) and ethylic alcohol (30%) was injected inside the mass under US guidance. The procedure was repeated at intervals of 15 days until the resolution of the symptoms. A total or partial symptomatic relief was obtained in 36 cases (90%). No procedure-related complications were observed. Transitory plantar pain, due to the flogistic reaction induced by the sclerosing solution, occurred in 6 cases (15%). The 10-month follow-up revealed a 20-30% mass volume reduction and an adiposus-like change in echotexture. In the 4 cases (10%) of therapeutic failure, the preliminary sonography demonstrated a hypoechoic echotexture with a strong US beam attenuation corresponding to a highly fibrous neuroma after surgical resection. The NAST is a feasible and cost-efficient procedure with high rates of therapeutic success
Modifications of midpalatal sutural density induced by rapid maxillary expansion: A low-dose computed-tomography evaluation.
INTRODUCTION: The aim of this study was to evaluate the density of the midpalatal
suture as assessed by low-dose computed tomography (CT) before rapid maxillary
expansion (RME) (T0), at the end of active expansion (T1), and after a retention
period of 6 months (T2).
METHODS: The study sample comprised 17 prepubertal subjects (mean age, 11.2
years) with constricted maxillary arches and unilateral or bilateral posterior
crossbite. The total amount of expansion was 7 mm in all subjects. Multi-slice
low-dose CT scans were taken at T0, T1, and T2. On axial CT scanned images, 4
regions of interest (ROIs) were placed along the midpalatal suture (anterior [AS
ROI] and posterior [PS ROI]) and in 2 regions of palatal bone (anterior and
posterior). Density was measured in Hounsfield units. The Mann-Whitney U test and
Friedman analysis of variance (ANOVA) with post-hoc test were used (P <0.05).
RESULTS: The densities in the AS and PS ROIs were significantly smaller than the
reference bone densities before RME therapy. Both AS and PS ROIs showed
significant decreases in density from T0 to T1, significant increases from T1 to
T2, and no significant differences from T0 to T2.
CONCLUSIONS: The effective opening of the midpalatal suture by RME in prepubertal
subjects was associated with a significant decrease in sutural density. The
sutural density after 6 months of retention post-RME indicated reorganization of
the midpalatal suture, since it showed values similar to the pretreatment ones
Immediate and post-retention effects of rapid maxillary expansion investigated by computed tomography in growing patients
Role of interventional radiology in pudendal neuralgia: A description of techniques and review of the literature [Ruolo della radiologia interventistica nella nevralgia del nervo pudendo: Descrizione della tecnica e revisione della letteratura]
Purpose: The authors sought to evaluate indications, technical feasibility and clinical efficacy of computed tomography (CT)-guided pudendal nerve infiltration in patients with chronic anoperineal pain by reviewing the role of the CT technique in their personal experience and in the recent interventional literature. Materials and methods: Twenty-eight women, mean age 50 years, and with a diagnosis of pudendal neuralgia on the basis of clinical and electromyographic criteria were enrolled in the study. CT-guided pudendal nerve injections were performed during three consecutive sessions held 2 weeks apart. In each session, patients received two percutaneous injections: one in the ischial spine, and the other in the pudendal (Alcock's) canal. Results: One patient dropped out of the study after the first session. At clinical assessment, 24h h after treatment, 21/27 patients reported significant pain relief. At follow-up at 3, 6, 9 and 12 months, 24/27 patients reported a ≥ 20% improvement in the Quality of Life (QOL) index. Conclusions. In pudendal nerve entrapment, CT-guided perineural injection in the anatomical sites of nerve impingement is a safe and reproducible treatment with a clinical efficacy of 92% at 12 months. © 2009 Springer-Verlag Italia
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