Browsing by Subject "POSTERIOR"

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  • Lanne, Markku; Luoto, Jani Pentti (2018)
    We propose imposing data-driven identification constraints to alleviate the multimodality problem arising in the estimation of poorly identified dynamic stochastic general equilibrium models under non-informative prior distributions. We also devise an iterative procedure based on the posterior density of the parameters for finding these constraints. An empirical application to the Smets and Wouters () model demonstrates the properties of the estimation method, and shows how the problem of multimodal posterior distributions caused by parameter redundancy is eliminated by identification constraints. Out-of-sample forecast comparisons as well as Bayes factors lend support to the constrained model.
  • Junnuthula, Vijayabhaskarreddy; Sadeghi Boroujeni, Amir; Cao, Shoupeng; Tavakoli, Shirin; Ridolfo, Roxane; Toropainen, Elisa; Ruponen, Marika; van Hest, Jan C. M.; Urtti, Arto (2021)
    Posterior eye tissues, such as retina, are affected in many serious eye diseases, but drug delivery to these targets is challenging due to various anatomical eye barriers. Intravitreal injections are widely used, but the intervals between invasive injections should be prolonged. We synthesized and characterized (H-1 NMR, gel permeation chromatography) block copolymers of poly(ethylene glycol), poly(caprolactone), and trimethylene carbonate. These polymers self-assembled to polymersomes and polymeric micelles. The mean diameters of polymersomes and polymeric micelles, about 100 nm and 30-50 nm, respectively, were obtained with dynamic light scattering. Based on single particle tracking and asymmetric flow field-flow fractionation, the polymeric micelles and polymersomes were stable and diffusible in the vitreous. The materials did not show cellular toxicity in cultured human umbilical vein endothelial cells in the Alamar Blue Assay. Pharmacokinetics of the intravitreal nanocarriers in the rabbits were evaluated using in vivo fluorophotometry. The half-lives of the polymersomes (100 nm) and the micelles (30 nm) were 11.4-32.7 days and 4.3-9.5 days. The intravitreal clearance values were 1.7-8.7 mu L/h and 3.6-5.4 mu L/h for polymersomes and polymeric micelles, respectively. Apparent volumes of distribution of the particles in the rabbit vitreous were 0.6-1.3 mL for polymeric micelles and 1.9-3.4 mL for polymersomes. Polymersomes were found in the vitreous for at least 92 days post-dosing. Furthermore, fundus imaging revealed that the polymersomes accumulated near the optic nerve and retained there even at 111 days post-injection. Polymersomes represent a promising technology for controlled and site-specific drug delivery in the posterior eye segment.
  • Choque-Velasquez, Joham; Resendiz-Nieves, Julio; Jahromi, Behnam Rezai; Colasanti, Roberto; Baluszek, Szymon; Muhammad, Sajjad; Hernesniemi, Juha (2020)
    OBJECTIVE: The midline supracerebellar infratentorial (SCIT) approach and its paramedian development are commonly used for dealing with pineal lesions. Comparative clinical studies are lacking, however. We aim to establish the better performance of the paramedian SCIT approach in terms of clinical safety in surgically treated pineal cysts and pineal region tumors. Procedural functionality and effectiveness have been also analyzed. METHODS: A comparative analysis of clinical, radiologic, pathologic, and surgical features, and outcome was performed between 55 midline and 57 paramedian SCIT approaches that were exclusively performed in 112 patients (57 pineal cysts and 55 tumors of the pineal region) operated in sitting position by a single surgeon. Information was retrieved from hospital records and microsurgical videos. RESULTS: The paramedian SCIT approach linked with fewer postoperative complications (odds ratio [OR]: 0.40) and fewer approach-related complications (OR: 0.28) than the midline SCIT approach. The SCIT paramedian approach was achieved in a shorter time, by a smaller bone flap, and with fewer complex procedural steps than the midline approach. The SCIT paramedian approach did not require the opening of the falx cerebelli, midline cerebellar retraction, section of the midline cerebellar draining veins, nor wide opening of the dura. Gross total resection, size of the lesion, microsurgical time for removal, histopathological diagnosis and postoperative outcome were statistically similar in both groups. CONCLUSIONS: The SCIT approach represents a safer and more functional approach for the removal of cysts and tumors of the pineal region than the classic midline approach, while maintaining the same effectiveness.