An automatic classification method for LANDSAT data as resulting from different experiences in the Italian environment

There are no author-identified significant results in this report

Green and soil brightness indicators obtained through a LANDSAT data transformation procedure

There are no author-identified significant results in this report

Evaluation of water transparency measurements derived from LANDSAT data and ground truth: An example from the Tiber River mouth

There are no author-identified significant results in this report

LANDSAT imagery of the Venetian Lagoon: A multitemporal analysis

The use of LANDSAT multispectral scanner images from 1975 to 1979 to determine pollution dispersion in the central basin of the lagoon under varying tidal conditions is described. Images taken during the late spring and representing both short and long range tidal dynamics were processed for partial haze removal and removal of residual striping. Selected spectral bands were correlated to different types of turbid water. The multitemporal data was calibrated, classified considering sea truth data, and evaluated. The classification differentiated tide diffusion, algae belts, and industrial, agricultural, and urban turbidity distributions. Pollution concentration is derived during the short time interval between inflow and outflow and from the distance between the two lagoon inlets and the industrial zones. Increasing pollution of the lagoon is indicated

Classification of submersed aquatic vegetation of the Venice lagoon using MIVIS airborne data

In July 2001 an aerial survey with MIVIS (Multispectral Infrared and Visible Spectrometer) hyperspectral sensor and an in situ survey campaign were performed on Venice lagoon to map benthic macro-algae and sea phanerogams distribution. On MIVIS VIS spectral range images, training areas for benthic macro-algae and sea phanerogams have been selected by using sea truth data collected by CNR-ISMAR from in situ campaign and periodic area surveys used in the lagoon by the local authorities. The derived spectral signature has been used to classify the area in order to produce the maps of the pure and mixture submersed vegetation population. The algorithm applied to the data is based on the Subpixel Spectral Analytical Process (SSAP) method. The method assumes that the spectrum of a single pixel is composed of a fraction of the material of interest while the remainder of the observed spectra contains background materials. In terms of recognition processes the produced maps present a very good agreement with the sea truth data even though the fraction material expressed in the maps does not represent a quantitative estimation of the material of interest

Knuckle pads mimic early psoriatic arthritis

Knuckle pads or Garrod\u2019s nodes are a rare, non-inflammatory condition. They consist of benign, well-circumscribed fibro-adipose tissue over the small joints of hands and feet. Knuckle pads may be under-diagnosed and mistaken for early arthritis. The rheumatologist should perform an accurate differential diagnosis in which he can be helped by ultrasound and by other colleagues, such as the dermatologist. Ultrasound is considered useful in the assessment of the thickening of the subcutaneous tissue, located usually on the extensor site of proximal interphalangeal and metacarpophalangeal hand joints. Dermoscopy may play a role in detecting epidermal and dermal changes. We hereby report the case of a female patient with knuckle pads mimicking psoriatic arthritis

Development and validation of a cell based model of insulin resistance and investigation into the intracellular molecular defects induced by diabetes and obesity

A reduction in the sensitivity of tissue to insulin is termed insulin resistance. In the clinic this condition is associated with obesity and inactivity and often leads to the development of type 2 diabetes. A major focus of antidiabetic therapy is to develop novel interventions to alleviate insulin resistance. However, the initial physiological and molecular defects in the development of insulin resistance remain elusive. This knowledge would greatly aid the development of novel and more effective insulin sensitisers.In an effort to improve the understanding of insulin resistance this thesis establishes that culturing liver cells in sera from obese diabetic patients reduces the ability of insulin to repress the key gluconeogenic gene, phosphoenolpyruvatecarboxykinase (PEPCK). Cells cultured in serum from obese diabetic human subjects exhibited defective PEPCK mRNA suppression by 0.1 and 0.5 nM insulin compared to cells cultured in control serum (p<0.0001), representing a shift to the right of the insulin dose response curve. Classification of human sera, using the response of the cell model following incubation with the sera, was actually more reliable than any single clinical biomarker at establishing whether the serum came from a volunteer with insulin resistance. This suggests that the cell model could be developed as a means to classify insulin resistance in the human population more reliably than simply measuring fasting glucose.The system was developed and optimised as a cell based humanised model of insulin resistance to aid the search for a biomarker for the development of obesity related insulin resistance. However, there was no linear relationship between any single biomarker and the resistance causing ability of the sera. Interestingly, cells cultured chronically in the presence of fetal calf serum supplemented with 5 pM insulin (the average increase in insulin between cases and controls) also exhibited reduced suppression of PEPCK by 0.1 and 0.5 nM insulin compared to controls (p=0.03 and 0.01 respectively). This has major implications for the understanding of how insulin resistance may develop. It suggests that minor increases in insulin release from beta cells, or minor loss of insulin clearance in the liver that elevate plasma insulin are potential initiating mechanisms for insulin resistance (at least in liver). Of course there may be many ways to initiate insulin resistance in vivo, but establishing the relative importance of the beta cell and the liver as an initial site for the development of insulin resistance is clearly important for effective intervention. Subsequent to the generation of insulin resistance in culture I could not detect significant differences in the response of the major post-receptor insulin signalling pathway components, between cells cultured under standard conditions and those cultured chronically in 5 pM insulin. Therefore the mechanism underlying this reduced insulin action on PEPCK gene transcription remains unclear.I then went on to develop reporter cell lines both for use in the study of the regulation of hepatic gene transcription by insulin and also as a potential screen for effective insulin sensitisers. Unfortunately the reporter cell lines did not turn out to be useful as hoped, as the reporter genes did not develop insulin resistance in response to chronic exposure to 5 pM insulin. In addition there were some differences between the reporter genes and endogenous genes in response to specific signalling inhibitors. This questions their suitability for the purposes proposed.Finally, I examined the signalling connections between the class of insulin sensitiser known as biguanides, and DNA repair mechanisms, as an initial characterisation of molecular links between diabetes and cancer. I established that inhibiting the DNA repair enzyme ATM reduces the phosphorylation of the biguanide target, AMPK in response to these drugs. However, although inhibition of ATM reduced biguanide suppression of G6Pase it had little effect on the regulation of PEPCK gene transcription by the drugs. This is consistent with AMPK not being the key mediator of biguanide regulation of PEPCK gene transcription and suggests that biguanide regulation of G6Pase and PEPCK gene transcription is mediated through distinct signalling pathways.In summary, I have developed a cell based model of insulin resistance that relies on factor (s) present in serum from humans with diabesity, and thus should be useful as a screen for more effective insulin sensitisers targeted at the population that donates the serum. It is likely that one of the factors responsible for generation of resistance is insulin itself as chronic exposure to low levels (albeit higher than background), of insulin reduces insulin sensitivity of the cells. The molecular details of the development of insulin resistance remain elusive as none of the major signalling pathways appear to be defective in the cells that have developed reduced insulin regulation of PEPCK. However, the data raise the intriguing possibility that chronic but mild hyperinsulinemia due to defective insulin secretion or clearance is an initial step in the development of insulin resistance. Hence, reducing insulin secretion (as opposed to current strategies of inducing insulin secretion) may be a more effective therapy for prevention of the development of insulin resistance. Finally, elements of the DNA repair pathways such as ATM may impinge on pathways that affect insulin sensitivity, including the biguanide target AMPK.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

a sonographic quantitative cutoff value of cerebral venous outflow in neurologic diseases a blinded study of 115 subjects

BACKGROUND AND PURPOSE: The autonomic nervous system maintains constant cerebral venous blood outflow in changing positions. Alterations in cerebral autoregulation can be revealed by postural changes at quantitative color Doppler sonography. The aim of this study was to reach an optimal cutoff value of the difference between the cerebral venous blood outflow in the supine and seated positions that can discriminate healthy controls from patients with multiple sclerosis and those with other neurologic diseases and to evaluate its specificity, sensitivity, and diagnostic accuracy. MATERIALS AND METHODS: One hundred fifteen subjects (54 with MS, 31 healthy controls, 30 with other neurologic diseases) underwent a blinded quantitative color Doppler sonography evaluation of cerebral venous blood outflow in the supine and sitting positions. An optimal difference value between the supine and sitting positions of the cerebral venous blood outflow cutoff value was sought. RESULTS: The difference value between supine and sitting positions of the cerebral venous blood outflow was ≤ 503.24 in 38/54 (70.37%) patients with MS, 9/31 (29.03%) healthy controls, and 13/30 (43.33%) subjects with other neurological diseases. A difference value between supine and sitting positions of the cerebral venous blood outflow at a 503.24 cutoff reached a sensitivity at 70.37%, a 70.96% specificity, a 80.85% positive predictive value, and a 57.89% negative predictive value; the quantitative color Doppler sonography parameters yielded significant differences. The difference value between supine and sitting positions of cerebral venous blood outflow ≤ 503.24 assessed the significant difference between MS versus other neurological diseases. CONCLUSIONS: Alteration of cerebral venous blood outflow discriminated MS versus other neurologic diseases and MS versus healthy controls. The difference value between supine and sitting positions of cerebral venous blood outflow ≤ 503.24 was statistically associated with MS

Experimental investigation of an atmospheric photoconductively switched high-voltage spark gap

We report on the experimental investigation of the photoconductively switched gas-filled spark gap. When the laser intensity of a femtosecond laser is high enough (around 1018 Wm-2), a plasma can be created that spans the complete distance between the electrodes. The gas-filled spark gap is then closed on a femtosecond timescale, similar to photoconductive switching of a semiconductor switch. Stochastic breakdown processes, such as avalanche and streamer formation that cause the breakdown in laser triggered spark gaps, are passed over, which results in faster risetime and less jitter. Measurements of the switched pulses as a function of laser energy were performed in a 1 mm gap at an applied voltage of 4.5 kV. A clear transition from triggering to switching was measured with increased laser energy. Measurements of the output pulses with the gap filled with nitrogen at 1 atm showed results very similar to measurements in air in the same gap. In the switching regime, the amplitude of the switched pulse did not depend strongly on the laser energy. Measurements at lower applied voltages but with the same gap distance showed that it was possible to switch voltages as low as 10% of the self-breakdown voltage. At low applied voltages, a significant difference between the applied voltage and the output voltage is measured. A possible explanation is given based on the dynamic behavior of the laser created plasma. The measured rise time and jitter of the switched pulses were both below the resolution of the measurement equipment, i.e., better than 100 ps and 15 ps, respectively

Transition phase towards psoriatic arthritis: Clinical and ultrasonographic characterisation of psoriatic arthralgia

Objective Non-specific musculoskeletal pain is common in subjects destined to develop psoriatic arthritis (PsA). We evaluated psoriatic patients with arthralgia (PsOAr) compared with psoriasis alone (PsO) and healthy controls (HCs) using ultrasonography (US) to investigate the anatomical basis for joint symptoms in PsOAr and the link between these imaging findings and subsequent PsA transition. Methods A cross-sectional prevalence analysis of clinical and US abnormalities (including inflammatory and structural lesions) in PsOAr (n=61), PsO (n=57) and HCs (n=57) was performed, with subsequent prospective follow-up for PsA development. Results Tenosynovitis was the only significant sonographic feature that differed between PsOAr and PsO (29.5% vs 5.3%, p<0.001), although synovitis and enthesitis were numerically more frequent in PsOAr. Five patients in PsOAr and one in PsO group developed PsA, with an incidence rate of 109.2/1000 person-years in PsOAr vs 13.4/1000 person-years in PsO (p=0.03). Visual Analogue Scale pain, Health Assessment Questionnaire, joint tenderness and US active enthesitis were baseline variables associated with PsA development. Conclusion Tenosynovitis was associated with arthralgia in subjects with psoriasis. Baseline US evidence of enthesitis was associated with clinical PsA development in the longitudinal analysis. These findings are relevant for enriching for subjects at risk of imminent PsA development