Sensitivity-based investigation of threshold voltage variability in 32-nm flash memory cells and MOSFETs

We investigate variability of a 32 nm flash memory cell and of 32 nm MOSFETs with a methodology based on sensitivity analysis performed with a limited number of TCAD simulations. We show that – as far as the standard deviation of the threshold voltage is concerned – our method provides results in very good agreement with those from three-dimensional atomistic statistical simulations, with a computational burden that is orders of magnitude smaller. We show that the proposed approach is a powerful tool to understand the role of the main variability sources and to explore the device design parameter space

A simplified transfer matrix approach for the determination of the complex modulus of viscoelastic materials

Nowadays, several analytical and numerical approaches are available for analysing the performance of materials used in noise and vibration control applications. All these methodologies require knowledge of a set of input parameters which, in the case of viscoelastic materials, could exhibit strong dependence on frequency in the entire audible range. The aim of this paper is to present a simplified transfer matrix approach for the determination of the complex modulus for longitudinal waves of isotropic viscoelastic materials as a function of frequency. To that effect, the tested material is excited by an electromagnetic shaker and longitudinal waves are investigated. Using a frequency sweep as an excitation signal, the time domain response is measured downstream and upstream of the sample itself. A velocity transfer function is measured and, by using a transfer matrix model of the experimental setup, the complex wave number for longitudinal waves and, consequently, the complex modulus can be determined once the Poisson’s ratio is known in advance. The results are presented and discussed for different materials and compared with well-established quasi-static and dynamic techniques

Ocular Refraction at Birth and Its Development During the First Year of Life in a Large Cohort of Babies in a Single Center in Northern Italy

The purpose of this study was to investigate refraction at birth and during the first year of life in a large cohort of babies born in a single center in Northern Italy. We also aimed to analyze refractive errors in relation to the gestational age at birth. An observational ophthalmological assessment was performed within 24 h of birth on 12,427 newborns. Refraction was examined using streak retinoscopy after the administration of tropicamide (1%). Values in the range of between +0.50 ≤ D ≤ +4.00 were defined as physiological refraction at birth. Newborns with refraction values outside of the physiological range were followed up during the first year of life. Comparative analyses were conducted in a subgroup of babies with known gestational ages. The following distribution of refraction at birth was recorded: 88.03% of the babies had physiological refraction, 5.03% had moderate hyperopia, 2.14% had severe hyperopia, 3.4%, had emmetropia, 0.45%, had myopia, 0.94% had astigmatism, and 0.01% had anisometropia. By the end of the first year of life, we observed reductions in hyperopia and astigmatism, and stabilization of myopia. Preterm babies had a four-fold higher risk of congenital myopia and a three-fold higher risk of congenital emmetropia as compared to term babies. Refraction profiles obtained at birth changed during the first year of life, leading to a normalization of the refraction values. Gestational age at birth affected the incidence of refractive errors and amblyopia

Widening use of dexamethasone implant for the treatment of macular edema

Sustained-release intravitreal 0.7 mg dexamethasone (DEX) implant is approved in Europe for the treatment of macular edema related to diabetic retinopathy, branch retinal vein occlusion, central retinal vein occlusion, and non-infectious uveitis. The implant is formulated in a biodegradable copolymer to release the active ingredient within the vitreous chamber for up to 6 months after an intravitreal injection, allowing a prolonged interval of efficacy between injections with a good safety profile. Various other ocular pathologies with inflammatory etio­pathogeneses associated with macular edema have been treated by DEX implant, including neovascular age-related macular degeneration, Irvine–Gass syndrome, vasoproliferative retinal tumors, retinal telangiectasia, Coats’ disease, radiation maculopathy, retinitis pigmentosa, and macular edema secondary to scleral buckling and pars plana vitrectomy. We undertook a review to provide a comprehensive collection of all of the diseases that benefit from the use of the sustained-release DEX implant, alone or in combination with concomitant therapies. A MEDLINE search revealed lack of randomized controlled trials related to these indications. Therefore we included and analyzed all available studies (retrospective and prospective, com­parative and non-comparative, randomized and nonrandomized, single center and multicenter, and case report). There are reports in the literature of the use of DEX implant across a range of macular edema-related pathologies, with their clinical experience supporting the use of DEX implant on a case-by-case basis with the aim of improving patient outcomes in many macular pathologies. As many of the reported macular pathologies are difficult to treat, a new treat­ment option that has a beneficial influence on the clinical course of the disease may be useful in clinical practice

Visual Outcomes of Pupilloplasty in Ocular Trauma and Iatrogenic Damage

Purpose: To report the visual outcomes of different techniques for iris pupilloplasty in eyes after traumatic and iatrogenic damage. Methods: 70 consecutive eyes with posttraumatic (80%) and postoperative (20%) iris damage were included. According to the preoperative diagnosis, the eyes were divided into three groups: mydriasis (50%), partial iris defects (24%), and iridodialysis (26%). Multiple techniques were performed: the Siepser slip-knot technique, the “lasso” technique, and suturing to the sclera. These techniques were combined in some cases. Results: The best improvement of visual acuity was found for the Siepser slip-knot technique with a median of 0.7 (SD ± 0.83) before surgery and 0.52 logMAR (SD ± 0.65) after surgery with regard to the surgical technique, and for mydriasis with a median of 0.7 (SD ± 0.75) before surgery and 0.52 logMAR (SD ± 0.49) after surgery with regard to preoperative diagnosis. Pupilloplasty was combined with additional surgery (corneal suturing, secondary intraocular lens implantation, anterior or pars plana vitrectomy) in 80% of cases. Apart from corneal suturing, all additional procedures ensured improvement in visual acuity. Conclusions: The slip-knot technique was the only suturing technique that resulted in a significant improvement in visual acuity. Other surgical procedures are usually needed in the majority of cases that undergo pupilloplasty, and they also give visual gain

Screen-printed Organic Electrochemical Transistors for the detection of ascorbic acid in food

[EN] Methods traditionally used for ascorbic acid (AA) detection in food are often expensive and complex, making them unsuitable for day-to-day determinations. In this work, we report on the use of all- PEDOT:PSS Organic Electrochemical Transistors (OECTs) for fast, simple and low-cost determination of AA in food. The performance of these OECTs was tested first with in lab-prepared solutions of AA with different concentrations. The effect of the geometry on the transistors performance for AA sensing was also investigated by comparing the response of two OECTs with different channel and gate areas ratio (g), in terms of current modulation, sensitivity, background signal and limit of detection (LOD). OECTs with smaller gate electrode than the channel (large g) show the best performance for AA sensing: these devices display smaller background signal, higher sensitivity, larger modulation and better LOD value (80.10^-6 M). Since the AA content in food rich in Vitamin C is in the mM range, these transistors can be considered sensitive enough for quantitatively monitoring AA in food. In order to demonstrate the reliability of the proposed sensors in real food samples, the response of these transistors was additionally measured in a commercial orange juice. The amount of AA obtained with the OECTs is in good agreement with that determined by HPLC and with values reported in the literature for orange juices. Furthermore, these OECTs can be considered promising candidates for the selective detection of AA in the presence of other interfering antioxidants.This work was supported by Spanish Government/FEDER funds (grant number MAT2015-64139-C4-3-R (MINECO/FEDER)) and Generalitat Valenciana funds (grant number AICO/2015/103).Contat-Rodrigo, L.; Pérez Fuster, C.; Lidon-Roger, JV.; Bonfiglio, A.; Garcia-Breijo, E. (2017). Screen-printed Organic Electrochemical Transistors for the detection of ascorbic acid in food. Organic Electronics. 45:89-96. https://doi.org/10.1016/j.orgel.2017.02.03789964

Polypoidal choroidal vasculopathy in pachychoroid: combined treatment with photodynamic therapy and aflibercept

Introduction: To evaluate the effects of combined therapy using intravitreal Aflibercept (IVA) and photodynamic therapy (PDT) on polypoidal choroidal vasculopathy related to pachychoroid disease (PPCV). Methods: Patients with PPCV were treated with PDT combined with 3 IVA injections on a monthly basis, followed by pro re nata criteria. The 12-month follow-up consisted of multiple revaluations of visual acuity and SS-OCT parameters of clinical activity. Results: Nineteen eyes were included in the study; mean age was 65.5 years. Visual acuity improved after 12 months (0.35 ± 0.25 to 0.2 ± 0.20 logMAR, p = 0.005). Percentage of eyes with intraretinal and subretinal fluid reduced from baseline to the 12-month follow-up (from 52.6 to 10.5%, p = 0.12, and from 89.5 to 5.3% p = 0.0009, respectively). Central retinal and mean macular thicknesses reduced (258 ± 39.6 to 204.8 ± 38.8 μm p = 0.04 and 293.8 ± 32.1 to 248.1 ± 29.6 μm p = 0.017, respectively). Central choroidal and mean choroidal thicknesses also displayed a reduction (328.6 ± 54.9 to 289.8 ± 44.6 μm p = 0.001 and 314.5 ± 55.3 to 287.9 ± 47.6 μm p = 0.015, respectively). The mean number of injections was 4.6/year. Conclusion: The results support the use of a combined therapy with Aflibercept and PDT in PPCV. This treatment would act in synergy, with anti-VEGF controlling exudation and PDT closing the aneurysmal vessel and reducing choroidal congestion