149 research outputs found
The influence of bond-rigidity and cluster diffusion on the self-diffusion of hard spheres with square-well interaction
Hard spheres interacting through a square-well potential were simulated using
two different methods: Brownian Cluster Dynamics (BCD) and Event Driven
Brownian Dynamics (EDBD). The structure of the equilibrium states obtained by
both methods were compared and found to be almost the identical. Self diffusion
coefficients () were determined as a function of the interaction strength.
The same values were found using BCD or EDBD. Contrary the EDBD, BCD allows one
to study the effect of bond rigidity and hydrodynamic interaction within the
clusters. When the bonds are flexible the effect of attraction on is
relatively weak compared to systems with rigid bonds. increases first with
increasing attraction strength, and then decreases for stronger interaction.
Introducing intra-cluster hydrodynamic interaction weakly increases for a
given interaction strength. Introducing bond rigidity causes a strong decrease
of which no longer shows a maximum as function of the attraction strength
Juxtapapillary Retinal Capillary Hemangioma: New Therapeutic Strategies
The treatment of juxtapapillary retinal capillary hemangiomas (JRCHs) is still a therapeutic dilemma without established guidelines. Because of the location of these hemangiomas on or adjacent to the optic nerve, treatment is difficult and complex, especially when JRCHs are located in the papillomacular bundle. This manuscript reviews the clinically relevant data on literature regarding the treatment of JRCHs, focusing on novel combined therapies that have shown promising results in these lesions
Amides and formamidines with antinociceptive activity: note II
Forty amides, formamidines and trifluoromethylsulfonylamides bearing on the nitrogen a cyclohexyl residue, eventually 2-substituted, were prepared and tested for analgesic activity against a chemical stimulus. Good activity was exhibited by amides 9, 11 and 28, by formamidine 34, as well as by triflyamide 40. Eleven additional compounds exhibited a moderate activity
Gaugino mass in AdS space
We study supersymmetric QED in AdS4 with massless matter. At 1-loop the
ultra-violet regulator of the theory generates a contribution to the gaugino
mass that is naively inconsistent with unbroken supersymmetry. We show that
this effect, known in flat space as anomaly mediated supersymmetry breaking, is
required to cancel an infra-red contribution arising from the boundary
conditions in AdS space, which necessarily break chiral symmetry. We also
discuss an analogous UV/IR cancellation that is independent of supersymmetry.Comment: 20 pages, 1 figur
Artificial intelligence in diabetic retinopathy screening: clinical assessment using handheld fundus camera in a real-life setting
Aim: Diabetic retinopathy (DR) represents the main cause of vision loss among working age people. A prompt screening of this condition may prevent its worst complications. This study aims to validate the in-built artificial intelligence (AI) algorithm Selena+ of a handheld fundus camera (Optomed Aurora, Optomed, Oulu, Finland) in a first line screening of a real-world clinical setting. Methods: It was an observational cross-sectional study including 256 eyes of 256 consecutive patients. The sample included both diabetic and non-diabetic patients. Each patient received a 50°, macula centered, non-mydriatic fundus photography and, after pupil dilation, a complete fundus examination by an experienced retina specialist. All images were after analyzed by a skilled operator and by the AI algorithm. The results of the three procedures were then compared. Results: The agreement between the operator-based fundus analysis in bio-microscopy and the fundus photographs was of 100%. Among the DR patients the AI algorithm revealed signs of DR in 121 out of 125 subjects (96.8%) and no signs of DR 122 of the 126 non-diabetic patients (96.8%). The sensitivity of the AI algorithm was 96.8% and the specificity 96.8%. The overall concordance coefficient k (95% CI) between AI-based assessment and fundus biomicroscopy was 0.935 (0.891-0.979). Conclusions: The Aurora fundus camera is effective in a first line screening of DR. Its in-built AI software can be considered a reliable tool to automatically identify the presence of signs of DR and therefore employed as a promising resource in large screening campaigns
Evidence that chronic hypoxia causes reversible impairment on male fertility
Aim: To evaluate the effect of chronic hypoxia on human spermatogenic parameters and their recovery time. Methods: Seminological parameters of six male healthy mountain trekkers were evaluated in normoxia at sea level. After 26 days exposure to altitude (ranging from 2 000 m to 5 600 m, Karakorum Expedition) the same parameters were again evaluated after returning to sea level. These parameters were once again evaluated after 1 month and then again after 6 months. Results: Sperm count was found to be lower immediately after returning to sea level (P = 0.0004) and again after a month (P = 0.0008). Normal levels were reached after 6 months. Spermatic motility (%) shows no reduction immediately after returning to sea level (P = 0.0583), whereas after 1 month this reduction was significant (P = 0.0066). After 6 months there was a recovery to pre-hypoxic exposure values. Abnormal or immature spermatozoa (%) increased immediately after returning to sea level (P = 0.0067) and then again after 1 month (P = 0.0004). After 6 months there was a complete recovery to initial values. The total number of motile sperm in the ejaculate was found to be lower immediately after returning to sea level (P = 0.0024) and then again after 1 month (P = 0.0021). After 6 months there was a recovery to pre-hypoxic exposure values. Conclusion: Chronic hypoxia induces a state of oligospermia and the normalization of such seminological parameters at the restoration of previous normoxic conditions after 6 months indicate the influence of oxygen supply in physiological mechanisms of spermatogenesis and male fertility. (Asian J Androl 2008 Jul; 10: 602–606
Advances in functional imaging of differentiated thyroid cancer
Abstract: The present review provides a description of recent advances in the field of functional imaging that takes advantage of the functional characteristics of thyroid neoplastic cells (such as radioiodine uptake and FDG uptake) and theragnostic approach of differentiated thyroid cancer (DTC). Physical and biological characteristics of available radiopharmaceuticals and their use with state-of-the-art technologies for diagnosis, treatment, and follow-up of DTC patients are depicted. Radioactive iodine is used mostly with a therapeutic intent, while PET/CT with 18F-FDG emerges as a useful tool in the diagnostic management and complements the use of radioactive iodine. Beyond 18F-FDG PET/CT, other tracers including 124I, 18F-TFB and 68Ga-PSMA, and new methods such as PET/MR, might offer new opportunities in selecting patients with DTC for specific imaging modalities or treatments
Role of serial cardiac 18F-FDG PET-MRI in Anderson-Fabry disease: a pilot study
Aim: We investigated the value of serial cardiac 18F-FDG PET-MRI in Anderson–Fabry disease (AFD) and the potential relationship of imaging results with FASTEX score.
Methods and results: Thirteen AFD patients underwent cardiac 18F-FDG PET-MRI at baseline and follow-up. Coefficient of variation (COV) of FDG uptake and FASTEX score were assessed. At baseline, 9 patients were enzyme replacement therapy (ERT) naïve and 4 patients were under treatment. Two patients presented a FASTEX score of 0 indicating stable disease and did not show any imaging abnormality at baseline and follow-up PET-MRI. Eleven patients had a FASTEX score > 20% indicating disease worsening. Four of these patients without late gadolinium enhancement (LGE) and with normal COV at baseline and follow-up had a FASTEX score of 35%. Three patients without LGE and with abnormal COV at baseline and follow-up had a FASTEX score ranging from 30 to 70%. Three patients with LGE and abnormal COV at baseline and follow-up had a FASTEX score between 35 and 75%. Finally, one patient with LGE and normal COV had a FASTEX score of 100%. Of the 12 patients on ERT at follow-up, FASTEX score was significantly higher in those 4 showing irreversible cardiac injury at baseline compared to 8 with negative LGE (66 ± 24 vs. 32 ± 21, p = 0.03).
Conclusion: 18F-FDG PET-MRI may be effective to monitor cardiac involvement in AFD
- …