1,720,995 research outputs found
Standards for transport of perishable goods are still adequate? Connections between standards and technologies in perishable foodstuffs transport
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Factors affecting energy consumptions and carbon footprint in refrigerated road transport: A brief review of recent advances in technology, materials and methods
No full textIn this paper some research related to the thermal insulation of the body, the energy consumption and the environmental impact of the cooling units are presented. The use of new materials such as the aerogels (both at ambient pressure and under vacuum conditions) is considered as an option and discussed in terms of performance, reliability and costs. Concerning usual solutions for the insulating walls based on polyurethane foams, the actual thermophysical properties of the blowing agents used in insulating walls are discussed in the view of the new regulations for the use of F-GAS refrigerants. The methods to calculate the air infiltration rate and radiative properties of the walls are commented. The ageing of the material used for the insulation body is discussed with the relative issues related to the appropriate prediction of the life of in-service units. Concerning the energy consumptions and environmental impact results from works related to the classic option of vapor compression cycles is compared to new ones such as cryogenic units in terms of total environmental impact, running costs and feasibility. Finally, works discussing new alternatives for refrigerants in vapor compression systems are presented
Optical Coherence Tomography Findings In Acute And Chronic Retinal Artery Occlusion.
No full textPurpose:To report spectral domain optical coherence tomography (SD-OCT) findings in acute and chronic retinal artery occlusions (RAO), and to compare these findings with other causes of inner retinal atrophy.
Methods:Two cases of central retinal artery occlusion (CRAO) with perfused cilio-retinal artery and one case of cilio-retinal artery occlusion were observed in the acute phase and then followed for four months with SD-OCT. Other 4 cases of chronic central and branch RAO were also evaluated. SD-OCT images of different causes of inner retinal atrophy (advanced glaucoma and ischemic optic neuropathy) are reported and compared.
Results:In the acute phase of RAO, SD-OCT discloses thickening and increased reflectivity of the inner retinal layers with shadowing effect on outer structures, and sharp demarcation between perfused and non-perfused retina. In the chronic phase, SD-OCT reveals severe and complete inner retinal atrophy and homogeneous intra-retinal structure, while outer nuclear layer and IS-OS/RPE hyper-reflective lines remain intact. On the contrary, in advanced glaucoma and optic neuropathy the inner retinal structure although reduced remains clearly detectable.
Conclusions:SD-OCT in acute-CRAO demonstrates swelling of the inner retinal layers and sharp demarcation of the affected. In the chronic phases the homogeneous inner atrophy with absence of identifiable retinal layers represents a distinctive marker of RAO compared with other causes of inner retinal atrophy
Dexamethasone Intravitreal Implant for Diabetic Macular Edema
No full textPurpose:It is well known that the presence of chronic and persistent diabetic macular edema (DME) can vanish the visual benefits of phacoemulsification (PE) in these patients. Nevertheless cataract extraction can be necessary both to maintain residual visual function and for a correct follow up of retinopathy. The use of dexamethasone intravitreal implant (Dex-I) at the time of surgery has an elevate rationale in these patients due to its combined high anti-inflammatory and anti-VEGF properties together with its long lasting effect and absence of systemic side effects. We here report the functional and anatomic results of a combined surgical procedure of Dex-I and PE in 7 patients with cataract and chronic DME followed for six months after surgery.
Methods:Seven consecutive type-2 diabetic patients with cystoid chronic DME and advanced nuclear cataract (N3-5 at LOCS-III chart) underwent PE. Dex-I was injected as the first surgical maneuver and than PE and IOL implantation proceeded as usual. Postop topical therapy for the first month included combined steroid/antibiotic and combined acetazolamide/β-blocker eye drops. Follow up visits were scheduled at one week and than monthly for 6 months. We measured variations in foveal thickness (FT) at SD-OCT, changes in ETDRS-visual acuity (VA) and in intraocular pressure (IOP).
Results:Mean preop FT was 344μ (range 278-489), preop visual acuity was 18 letters (range 5-26) and mean IOP 17mmHg (range 14-19). Mean preop glicated haemoglobin (HbA1c) was 7.2% (range 6.2-9.8). no complications were registered during or after the surgical procedure. During follow up, mean FT decreased by 122μ (range 81-213) at 1W, 137μ (76-198) at M1, remained unchanged at M2/M3 and than at M4 the gain reduced to 56μ (12-109) to progressively return to preop values at M5 and M6 (final mean FT 356μ). Mean VA change was +5 letters at 1W (range -1/+13), +8 (range +2/+12) at 1M, +11/13 (range +1/+16) at M2-3-4-5, and +9 (range +3/+8) at M6. IOP remained <23mmHg in all patients (hypotensive eye drops maintained until M6 in 3 patients).
Conclusions:In this small case series, Dex-I avoided worsening of chronic DME after cataract extraction and also improved foveal thickness for up to 4-5 months. Dex-I appears to be a good surgical adjuvant in these cases, but larger studies are necessary to confirm these data
Frammento premaculare di telino chirurgico: una possibile causa di deficit visivo post-operatorio
No full textChoroidal thickness changes during Anti-VEGF therapy for AMD.
No full textPurpose:to evaluate variations in choroidal thickness during anti-VEGF therapy for neovascular AMD
Methods:We retrospectively measured choroidal thickness (CT) in all eyes treated in the last six months with intravitreal ranibizumab for subfoveal choroidal neovascularization (CNV) secondary to AMD. CT was calculated with SD-OCT (Spectralis, Heidelberg) by two independent observers from the outer border of RPE line to the iperreflective line behind the large vessel layer of the choroid. We compared CT before the first injection (T0) with CT one month after the third monthly injection (T1). Type of CNV and BCVA (ETDRS chart) were also registered.
Results:We analyzed 33 consecutive eyes of 33 patients (mean age 76 yo). At T0 mean BCVA was 32 letters and the range of the refractive error was ± 2.3 SE. Twentyfour eyes had an occult CNV, 3 eyes had a classic CNV and 6 eyes had a minimally classic CNV. After four months of therapy, the mean foveal CT decreased from 187μm (± 71) to 166 μm (±67), and this difference resulted highly statistically significant (p <0.0001). CT remained stable in only 4 eyes, while in 29 eyes it decreased from 9 to 72 μm (mean 21 μm).
Conclusions:Anti-VEGF therapy seems to reduce choroidal thickness in neovascular AMD. Further studies with longer follow-up and higher number of eyes are necessary to confirm these data
Correlation between foveal choroidal thickness with age, refraction and axial lenght.
No full textPurpose:to correlate foveal choroidal thickness (CT) with age, refraction and axial lenght.
Methods:we examined with SD-OCT (OPKO-OTI) 84 healthy subjects ageing between 15 and 83 years with refraction between +2 and -35 Sferical Equivalent. We obtained an horizontal scan at foveal level and measured CT from RPE line to the iperreflective line behind the large vessel layer of the choroid. Axial length (IOL Master, Carl Zeiss Meditec) was also evaluated. We divided the eyes into 3 groups according to the age (GrA 65 yrs) and in each group CT was correlated with refraction and axial length.
Results:After excluding eyes with concomitant pathologies other than high myopia, 143 eyes were evaluated. Ageing was associated with a progressive decrease in CT, from a mean of 305 μm in GrA to 190 μm in GrB and 145 μm in GrC. Increasing myopic refraction and axial length were associated with a progressive CT decrease in each group of age. CT showed a statistical difference between emmetropic eyes (±2 D, mean CT 312 μm) and those presenting simple myopia (<6 D, mean CT 243 μm). Over 16 D, mean CT was 72.5 μm (about four times thinner than in emmetropic eyes). At high levels of myopia however, axial length was more correlated with CT decrease than refractive error.
Conclusions:Choroidal thickness progressively decreases according to the age, with a significant loss detectable since the age of forty. High myopia is characterized by a typical and marked choroidal thinning, more correlated to axial length than to refractive error
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