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Biomedical subjects

E Martines

Publications and source records attributed to E Martines.

16 recordsLinked to original sources
PubMed2006

Newborn hearing screening project using transient evoked otoacoustic emissions: Western Sicily experience.

OBJECTIVE: To study the incidence of congenital sensorineural hearing loss in all newborns introducing a screen test with a protocol no expensive, with a good "screen sensitivity" that could let an earlier identification of hearing impairment beginning early intervention by 2 months of age and increasing the probability of having language development within the normal range of development. METHODS: The study was conducted in Sciacca hospital from the beginning of 2003 to our days and was carried out with transient evoked otoacoustic emission using the criteria for PASS or RETEST and considering eventual prenatal and perinatal risk factors. All the newborns were divided into four groups each one with its personal secondary step program. RESULTS: In the years 2003-2004 the number of the newborns in Sciacca hospital was: 538 for 2003, 653 for 2004 with a total of 1191; all these infants were divided in three groups: resident in Sciacca, resident in the Sciacca borderlands and resident out of the district of Sciacca. The coverage (percentage of the target population who undergo the screen) was of 90% in the 2003 (483 newborns) and of 90% in the 2004 (585 newborns) with two cases of congenital sensorineural hearing loss identified. The incidence of sensorineural hearing loss, in the District of Sciacca, was estimated to be 2.07/1000 in 2003 and 1.70/1000 in 2004. CONCLUSIONS: The higher incidence of sensorineural hearing loss in our study is due to a high prevalence of consanguineous marriage in Sicily that was shown to be linked with hearing impairment. The "sensitivity value" was 95% at the first step but became 99% after the second step with a few number of false positive (0.74%). All the infants with a diagnosis of sensorineural hearing loss began a rehabilitation program before the age of 5 months and they have a good speech development and speech intelligibility.

Consanguinity↗
PubMed2004

Vortex-induced diffusivity in reversed field pinch plasmas.

Coherent structures identified in two reversed field pinch experiments are interpreted as a dynamic balance of dipolar and monopolar vortices growing and evolving under the effect of the ExB flow shear. For the first time their contribution to the anomalous transport has been estimated in fusion related plasmas, showing that they can account for up to 50% of the total plasma diffusivity. The experimental findings indicate that the diffusion coefficient associated with the coherent structures depends on the relative population of the two types of vortices and is minimum when the two populations are equal. An interpretative model is proposed to explain this feature.

Journal Article↗
PubMed2004

Kink instability in applied-field magneto-plasma-dynamic thrusters.

Measurements of magnetic and electrostatic fluctuations in an applied field magneto-plasma-dynamic thruster have shown that a m/n=1/1 kink mode becomes unstable whenever the Kruskal-Shafranov limit is violated. A positive correlation is established between the kink and performance degradation at high current, which has until now prevented the use of this kind of thruster in space missions.

Journal Article↗
PubMed2001

Transport processes in reversed-field-pinch plasmas: inconsistency with the self-organized-criticality paradigm.

A statistical analysis of the anomalous particle flux in the edge region of the RFX experiment has revealed that laminar times between bursts, which account for more than 50% of the losses, have a power law distribution and that flux fluctuations are not self-similar. These properties are found in contrast with a wide class of self-organized-criticality models so that it is concluded that there is no experimental evidence of avalanchelike process occurrence in the plasma of RFX.

Journal Article↗
PubMed2001

Search of self-organized criticality processes in magnetically confined plasmas: hints from the reversed field pinch configuration.

In order to test the self-organized criticality (SOC) paradigm in transport processes, a novel technique has been applied for the first time to plasmas confined in reversed field pinch configuration. This technique consists of an analysis of the probability distribution function of the times between bursts in density fluctuations measured by microwave reflectometry and electrostatic probes. The same analysis has also been applied to intermittent events sorted out from the Gaussian background. In both cases, the experimental results disagree with the predictions for a SOC system.

Journal Article↗
PubMed2000

Quasi-single-helicity reversed-field-pinch plasmas

The reversed field pinch (RFP) is a configuration for plasma magnetic confinement. It has been traditionally viewed as dominated by a bath of MHD instabilities producing magnetic chaos and high energy transport. We report experimental results which go beyond this view. They show a decrease of magnetic chaos and the formation of a coherent helical structure in the plasma, whose imaging and temperature profile are provided for the first time. These quasi-single-helicity states are observed both transiently and in stationary conditions. The last case is consistent with a theoretically predicted bifurcation. Our results set a new frame for improving confinement in high current nonchaotic RFP's.

Journal Article↗
PubMed2000

Intermittency and turbulence in a magnetically confined fusion plasma

We investigate the intermittency of magnetic turbulence as measured in reversed field pinch plasmas. We show that the probability distribution functions of magnetic field differences are not scale invariant; that is, the wings of these functions are more important at the smallest scales, a classical signature of intermittency. We show that scaling laws appear also in a region very close to the external wall of the confinement device, and we present evidences that the observed intermittency increases moving towards the wall.

Journal Article↗
PubMed1996

Photorefractive keratectomy for residual myopia after radial keratotomy.

PURPOSE: To evaluate the results of photorefractive keratectomy (PRK) to treat undercorrected radial keratotomy (RK). SETTING: Instituto de Oftalmologia Tadeu Cvintal, São Paulo, Brazil. METHODS: A consecutive series of 28 eyes that had PRK to treat residual myopia after RK were studied. Refractive visual and safety data were collected and evaluated. RESULTS: One year after PRK, 75% of eyes had an uncorrected visual acuity of 20/25 or better and 85%, 20/40 or better. All but one case maintained or improved best corrected visual acuity; one case decreased from 20/25 to 20/30. At 1 year, 75% of eyes were within 0.50 diopter (D) of emmetropia and 90% were within 1.00 D. Only one case was more than 1.00 D undercorrected (-1.125 D) at 1 year. Mean pre-RK myopia was -5.90 D (range -2.00 to 11.80 D). Mean spherical equivalent improved from the residual postoperative level of -2.71 D +/- 0.86 (SD) before PRK to -0.21 +/- 0.86 D 1 to 3 months after PRK and to -0.40 +/- 0.43 D 1 year after PRK. CONCLUSION: Photorefractive keratectomy was efficacious in correcting residual myopia after RK in a group of selected patients.

Cohort Studies↗
PubMed1996

The Martines enhancement technique for correcting residual myopia following laser assisted in situ keratomileusis.

BACKGROUND AND OBJECTIVE: Laser assisted in situ keratomileusis (LASIK) is highly effective for correcting moderate to severe levels of myopia with rapid visual recovery, minimal pain and easier post-operative management compared with Photorefractive keratectomy. Nevertheless, undercorrection may occur. The purpose of this paper is to evaluate 14 undercorrected LASIK cases in which the cap was dissected and the stromal bed re-ablated using a method developed by one of the authors (EM). PATIENTS AND METHODS: Among a series of 297 LASIK procedures, visual and refractive results of 14 cases undergoing enhancement were evaluated. All cases were targeted for plano refraction. RESULTS: All 14 cases were followed at least 6 months and 7 (50%) have been followed two years. Mean pre-LASIK myopia of -14.60 +/- 4.90 D had been reduced to a mean of -4.50 +/- 2.60 D prior to enhancement. Following enhancement mean spherical equivalent was -0.22 D at 6 months. Results were stable at two years. All cases were within 1.25 D of target and 11 of 14 were within one diopter. Uncorrected vision was improved in all cases. Best corrected vision was maintained or improved in all but one case. This case had a decentered ablation. CONCLUSION: Laser enhancement of undercorrected LASIK cases using the Martines Technique was predictable and efficacious.

Adult↗
PubMed1995

Small-diameter corneal inlay in presbyopic or pseudophakic patients.

We report the results of using the small-diameter corneal inlay to create a bifocal cornea. The inlay was implanted in five eyes in January 1993. At 12 months postoperatively, uncorrected near vision had improved from J4 to better than J2 in four of the five. The results indicate that the corneal inlay improves near vision and is compatible within the cornea.

Adult↗
PubMed1991

The Jervell and Lange-Nielsen syndrome.

Deafness and electrocardiographic changes (prolongation of the Q-T interval and inversion of the T wave) with a clinical picture of syncopal attacks and sudden death, were described as a distinct syndrome by Jervell and Lange-Nielsen in 1957. The syndrome is inherited as an autosomal recessive trait. In this study, all the cases reported since 1957 and their proposed prevalence are reviewed. The authors describe the 4 cases they have studied, all of which presented congenital sensorineural hearing loss and electrocardiographic changes characteristic of the syndrome. The relatively high number of cases they have encountered casts doubt on literature that states that the syndrome occurs more frequently in Northern-European populations. Consequently, it is advisable to perform an electrocardiogram in all children affected by congenital deafness.

Audiometry↗
PubMedDate not supplied

Photorefractive keratectomy following penetrating keratoplasty.

We present 3 eyes that underwent photorefractive keratectomy (PRK) for residual myopia after penetrating keratoplasty, and 1 eye that was treated for recurrent granular dystrophy and myopia following penetrating keratoplasty. The 3 refractive eyes experienced improvements in visual acuity and refractive error through 3 months postoperative, but exhibited regression of effect after 6 months postoperative. One eye also exhibited substantial corneal haze at three months postoperative that was not responsive to steroid retreatment. The eye with granular dystrophy obtained symptomatic relief as well as improvement in vision. We tentatively conclude that the corneal transplant reacts to photorefractive keratectomy in much the same way as a normal cornea. Eyes with substantial degrees of post-graft myopia exhibit regression of refractive effect, much like high myopes following primary photorefractive keratectomy. Photorefractive was unable to prevent the recurrence of granular dystrophy in the transplanted tissue. The eyes reported here achieved only modest long-term visual and refractive improvements.

Adult↗
PubMedDate not supplied

Excimer laser photoablation of primary familial amyloidosis of the cornea.

A 31-year old female underwent lamellar keratoplasty for the treatment of bilateral primary familial amyloidosis of the cornea in 1983 (OS), 1986 (OD), and 1989 (OS). The lesions recurred bilaterally and visual acuity in 1992 was 20/400 in each eye. After debridement of essentially all corneal epithelium, the entire cornea of the left eye was treated with excimer laser phototherapeutic keratectomy (PTK). One month postoperatively, visual acuity was 20/50 and the corneal surface appeared smooth and clear with no evidence of recurrence. Four months postoperatively, the patient continued to be free of recurrence.

Adult↗