The globalizability of temporal discounting.

Economic inequality is associated with preferences for smaller, immediate gains over larger, delayed ones. Such temporal discounting may feed into rising global inequality, yet it is unclear whether it is a function of choice preferences or norms, or rather the absence of sufficient resources for immediate needs. It is also not clear whether these reflect true differences in choice patterns between income groups. We tested temporal discounting and five intertemporal choice anomalies using local currencies and value standards in 61 countries (N = 13,629). Across a diverse sample, we found consistent, robust rates of choice anomalies. Lower-income groups were not significantly different, but economic inequality and broader financial circumstances were clearly correlated with population choice patterns.

Pulsed Wave Doppler Measurements of Maximum Velocity: Dependence on Sample Volume Size.

Pulsed wave (PW) Doppler ultrasound is routinely used in the clinic to assess blood flow. Our annual Doppler quality assurance tests revealed unexpectedly large errors in measurement of maximum velocity, exceeding our tolerance (error >20%), when using certain scanners with small Doppler sample volume dimensions. The aim of this study was to assess the dependence of maximum velocity estimates on PW Doppler sample volume size. A flow phantom with known steady flow was used to acquire maximum velocity estimates (maximum velocities of 24, 39 and 85 cm/s and sample volume range of 0.3-20 mm) with a variety of transducers and scanners in clinical use (51 probes from 4 manufacturers). Selected acoustic outputs were characterized using free-field hydrophone measurements. All maximum velocity estimates were within our tolerance for sample volume sizes ≥1.5 mm, although maximum velocity estimates typically increased with decreasing sample volume size. Errors exceeding our tolerance were commonly found for one manufacturer when using smaller sample volumes, resulting in up to 75% overestimation. Although intrinsic spectral broadening based on transit time considerations may help explain our findings, the sample volume dependence raises potential clinical concerns that users should be aware of and which manufacturers should consider addressing.

A Polyvinyl Alcohol-Based Thermochromic Material for Ultrasound Therapy Phantoms.

Temperature estimation is a fundamental step in assessment of the efficacy of thermal therapy. A thermochromic material sensitive within the temperature range 52.5°C-75°C has been developed. The material is based on polyvinyl alcohol cryogel with the addition of a commercial thermochromic ink. It is simple to manufacture, low cost, non-toxic and versatile. The thermal response of the material was evaluated using multiple methods, including immersion in a temperature-controlled water bath, a temperature-controlled heated needle and high-intensity focused ultrasound (HIFU) sonication. Changes in colour were evaluated using both RGB (red, green, blue) maps and pixel intensities. Acoustic and thermal properties of the material were measured. Thermo-acoustic simulations were run with an open-source software, and results were compared with the HIFU experiments, showing good agreement. The material has good potential for the development of ultrasound therapy phantoms.

A complex flow phantom for medical imaging: ring vortex phantom design and technical specification.

Cardiovascular fluid dynamics exhibit complex flow patterns, such as recirculation and vortices. Quantitative analysis of these complexities supports diagnosis, leading to early prediction of pathologies. Quality assurance of technologies that image such flows is challenging but essential, and to this end, a novel, cost-effective, portable, complex flow phantom is proposed and the design specifications are provided. The vortex ring is the flow of choice because it offers patterns comparable to physiological flows and is stable, predictable, reproducible and controllable. This design employs a piston/cylinder system for vortex ring generation, coupled to an imaging tank full of fluid, for vortex propagation. The phantom is motor-driven and by varying piston speed, piston displacement and orifice size, vortex rings with different characteristics can be produced. Two measurement methods, namely Laser-PIV and an optical/video technique, were used to test the phantom under a combination of configurations. Vortex rings with a range of travelling velocities (approximately 1-80 cm/s) and different output-orifice diameters (10-25 mm) were produced with reproducibility typically better than ±10%. Although ultrasound compatibility has been demonstrated, longer-term ambitions include adapting the design to support comparative studies with different modalities, such as MRA and X-ray-CTA.

Subconjunctival and/or intrastromal bevacizumab injections as preconditioning therapy to promote corneal graft survival.

The purpose of this study is to investigate whether subconjunctival and/or intrastromal Bevacizumab injections could help to prevent graft failure in high-risk keratoplasties. Twenty seven eyes of 27 patients, affected by high immune rejection risk and corneal neovascularization, were involved in this prospective interventional case-control series (case group: 14 eyes and control group: 13 eyes). Case group was submitted to a cycle of three subconjunctival and/or intrastromal injections of 5 mg/0.2 ml Bevacizumab. After a mean period of 6.36 months ± 3.38 SD from the last injection, all patients underwent keratoplasty. An adjunctive injection was performed intraoperatively at the end of the surgical procedure. Control group did not receive any Bevacizumab injection, but directly underwent keratoplasty. Each patient was submitted to a complete eye examination and corneal confocal microscopy. The absence of immune rejection signs in the graft, at clinical and confocal microscopy examination, was considered as main outcome measure. All cases showed less ocular inflammation and activity of vessels. No side effects were detected after the injection procedure. No corneal graft rejection was seen during the follow-up (mean 26.1 months ± 5.7 SD) in the case group. Six eyes of the control group showed graft rejection 3.8 months ± 1.4 SD after keratoplasty. As a conclusion, Bevacizumab injection may represent a preconditioning treatment to improve prognosis in high-risk corneal transplantation. The procedure seems to be safe and it may help to reduce the inflammatory stimulus that plays a key role in corneal graft rejection.

Ocular mucous membrane pemphigoid after Lyell syndrome: occasional finding or predisposing event?

PURPOSE: Ocular mucous membrane pemphigoid (OMMP) is an autoimmune disease involving the eye and characterized by subepithelial detachment resulting from an immunologic reaction against conjunctival basal membrane zone (BMZ) antigens. Lyell syndrome (LS) is a drug-induced, T cell-mediated, cytotoxic reaction involving the mucocutaneous areas. Two patients with LS are presented in whom OMMP developed. DESIGN: Report of 2 cases. PARTICIPANTS: Two male patients, 80 and 60 years old, with persistent corneal ulcerations, corneal melting, and inflammation some months after an LS episode. METHODS: Conjunctival biopsy samples were obtained to perform direct immunofluorescence (DIF) and histologic analyses. Indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) also were performed. MAIN OUTCOME MEASURES: Immunodeposit findings on the conjunctival BMZ obtained by DIF and IIF, inflammatory infiltration of the corneoconjunctival samples studied by histologic analysis, and autoantibodies of patient sera directed against BMZ antigens tested by ELISA. RESULTS: Direct immunofluorescence analyses showed immunoglobulin G and complement 3 component deposits along the BMZ in a linear pattern. Histologic analysis revealed the presence of eosinophils, neutrophils, and mast cells with fibrin deposition in the substantia propria of both patients; the data confirmed the clinical suspicion of OMMP. The IIF and ELISA results were negative. CONCLUSIONS: Chronic eye surface injury associated with LS may promote autoimmunization against ocular epithelial BMZ antigens, playing a strategic role in the subsequent onset of OMMP. The occurrence of OMMP after LS could be an occasional finding, or conversely, LS could be an underestimated predisposing factor in the development of OMMP.