Sustained Release Of Calcium Hydroxide From Poly(DL-lactide-co-glycolide) Acid Microspheres For Apexification

Calcium hydroxide (Ca(OH)2) loaded poly(DL-lactide-co-glycolide) acid (PLGA) microspheres (MS) might be employed for apexification requiring a sustained release of Ca++. The aim of this study was to formulate and characterize Ca(OH)2-PLGA-MS. The Ca(OH)2-loaded MS were prepared by either oil-in-water (O/W) or water-in-oil/in-water (W/O/W) emulsion solvent evaporation technique. MS produced by the O/W technique exhibited a larger diameter (18.63 ± 7.23 μm) than the MS produced by the W/O/W technique (15.25 ± 7.37 μm) (Mann Whitney U test P \u3c 0.001). The Ca(OH)2 encapsulation efficiency and Ca++ release were calculated from data obtained by absorption techniques. Ca++ release profile was evaluated for 30 days. The percentage of encapsulation efficiency of the O/W-produced MS was higher (24%) than the corresponding percentage of the W/O/W-produced MS (11%). O/W- and W/O/W-produced MS released slower and lower Ca++ than a control Ca(OH)2 paste with polyethylene glycol 400 (ANOVA 1 way, Tukey HSD P \u3c 0.01). O/W-produced MS released higher Ca++ than W/O/W-produced MS (statistically significant differences with t-Student test). We concluded that Ca(OH)2-PLGA-MS were successfully formulated; the technique of formulation influenced on the size, encapsulation efficiency and release profile. The MS were better sustained release system than the Ca(OH)2 paste

Fiscal Policy, Inequality and the Poor in the Developing World

Using comparable fiscal incidence analysis, this paper examines the impact of fiscal policy on inequality and poverty in 25 countries for around 2010. Success in fiscal redistribution is driven primarily by redistributive effort (share of social spending to GDP in each country) and the extent to which transfers/subsidies are targeted at the poor and direct taxes targeted at the rich. While fiscal policy always reduces inequality, this is not the case with poverty. Fiscal policy increases poverty in 4 countries using a US$1.25/day PPP poverty line, in 8 countries using a US$2.50/day line, and in 15 countries using a US$4/day line (over and above market income poverty). Net direct taxes are always equalizing and net indirect taxes are equalizing in 17 of the 25 countries. While spending on pre-school and primary school is pro-poor (i.e. the per capita transfer declines with income) in almost all countries, pro-poor secondary school spending is less prevalent, and tertiary education spending tends to be progressive only in relative terms (i.e. equalizing but not pro-poor). Health spending is always equalizing

Wireless multichannel optogenetic stimulators enabled by narrow bandwidth resonant tank circuits

Optogenetic neuromodulation is a powerful technique used to study cells that form part of neuronal circuits. Light stimulation of neurons has led to a deeper understanding of autism, schizophrenia and depression. However, researchers are often limited to tethered systems involving percutaneous plugs, hence, wireless power transmission to an implantable device is desirable. This work details the design, fabrication and testing of multichannel wirelessly powered optogenetic devices. By employing several carefully tuned resonant tank circuits, this work demonstrates the ability to address a scalable number of light sources on a single device. Single channel, dual channel and 16 channel devices were fabricated, achieving light output readings of up to 15mW at 473nm, suitable for activating channelrhodopsin. Wireless power transmission was characterized in air and porcine tissue for implant depths up to 30mm, making device implantation feasible. The device was successful in activating endogenous (in retinal ganglion cells) and exogenously transfected channelrhodopsin in human embryonic kidney cells, providing biological validation. The significance of this approach is the removal of power-hungry and area-consuming electronics from the implant, while the ability to address and modulate individual light sources is maintained by shifting this complexity to the external wireless power transmitter. © 2017 Elsevier B.V