Preparation and in vitro characterization of lipospheres as a carrier for the cosmetic application of glycolic acid

Lipospheres for the cosmetic delivery of glycolic acid were prepared by the melt method using tristearin as the lipid phase and hydrogenated soybean phosphatidylcholine as the emulsifier. The lipospheres, sized from 5 to 40 micron, contained a rather high glycolic acid loading level probably due to a partial polymorphic modification of the lipid and determined glycolic acid sustained release pattern

How citation boosts promote scientific paradigm shifts and Nobel Prizes

Nobel Prizes are commonly seen to be among the most prestigious achievements of our times. Based on mining several million citations, we quantitatively analyze the processes driving paradigm shifts in science. We find that groundbreaking discoveries of Nobel Prize Laureates and other famous scientists are not only acknowledged by many citations of their landmark papers. Surprisingly, they also boost the citation rates of their previous publications. Given that innovations must outcompete the rich-gets-richer effect for scientific citations, it turns out that they can make their way only through citation cascades. A quantitative analysis reveals how and why they happen. Science appears to behave like a self-organized critical system, in which citation cascades of all sizes occur, from continuous scientific progress all the way up to scientific revolutions, which change the way we see our world. Measuring the "boosting effect" of landmark papers, our analysis reveals how new ideas and new players can make their way and finally triumph in a world dominated by established paradigms. The underlying "boost factor" is also useful to discover scientific breakthroughs and talents much earlier than through classical citation analysis, which by now has become a widespread method to measure scientific excellence, influencing scientific careers and the distribution of research funds. Our findings reveal patterns of collective social behavior, which are also interesting from an attention economics perspective. Understanding the origin of scientific authority may therefore ultimately help to explain, how social influence comes about and why the value of goods depends so strongly on the attention they attract.Comment: 6 pages, 6 figure

Measurement of the 10 keV resonance in the 10^{10}B(p,α0p, \alpha_0)7^7Be reaction via the Trojan Horse Method

The $^{10}$B(p,$\alpha_0$)$^7$Be bare nucleus astrophysical S(E)-factor has been measured for the first time at energies from about 100 keV down to about 5 keV by means of the Trojan Horse Method (THM). In this energy region, the S(E)-factor is strongly dominated by the 8.699 MeV $^{11}$C level (J$^{\pi}$=$\frac{5}{2}$$^+$), producing an s-wave resonance centered at about 10 keV in the entrance channel. Up to now, only the high energy tail of this resonant has been measured, while the low-energy trend is extrapolated from the available direct data. The THM has been applied to the quasi-free $^2$H($^{10}$B,$\alpha_0$$^7$Be)n reaction induced at a boron-beam energy of 24.5 MeV. An accurate analysis brings to the determination of the $^{10}$B(p,$\alpha_0$)$^7$Be S(E)-factor and of the corresponding electron screening potential $U_e$, thus giving for the first time an independent evaluation of it.Comment: Authors thank the (anonymous) referee for detailed comments and suggestions. The paper is already submitted to Physical Review

Low-energy d+d fusion via the Trojan Horse Method

The 2H(d,p)3H and 2H(d,n)3He reactions have been recently investigated from Edd=1.5 MeV down to 2 keV, by means of the Trojan Horse Method (THM) applied to the Quasi Free 3He+d interaction at 18 MeV [1]. The knowledge of their fusion cross section at low energies is of interest for pure and applied physics. Both reactions belong to the network of processes to fuel the first inertial confinement fusion reactors in the range of kT= 1 to 30 keV. These energies overlap with the burning temperatures of deuterium in the Pre-main sequence of stellar evolution. They are key processes in the Standard Big Bang Nucleosynthesis (SBBN), in an energy region from 50 to 300 keV and experimental data at least up to 1 MeV are required for an accurate calculation of the reaction rate. Providing experimental data for both channels from a single experiment and over the entire energy range of interest is crucial for an accurate calculation of the reaction rates. This is what has been obtained from the present Trojan Horse (TH) investigation with new reaction rates which deviate by more than 20% from available direct data. This represents also the first pioneering experiment in quasi free regime where the charged spectator is detected

Electron screening effects in (p,α) reactions induced on boron isotopes studied via the Trojan Horse Method

The Trojan Horse Method is a powerful indirect technique allowing one to measure the bare nucleus S(E)-factor and the electron screening potential for astrophysically relevant reactions without the needs of extrapolations. The case of the (p,α) reactions induced on the two boron isotopes 10,11B is here discussed in view of the recent Trojan Horse (TH) applications to the quasi-free 10,11B+2H reactions. The comparison between the TH and the low-energy direct data allowed us to determine the electron screening potential for the 11B(p,α) reaction, while preliminary results on the 10B(p,α) reaction have been extracted

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Characterization of tamoxifen in crosslinked alginate microparticles

Purpose: Physical-chemical characterisation of tamoxifen (TMX) in alginate microparticles for the uptake by Peyer’s patches after oral administration. Methods: Uncrosslinked microparticles were prepared by spray-drying of hydro-alcoholic solutions of alginate/TMX (1:0.1) mixtures. A subsequent crosslinking process by calcium ions and chitosan provides crosslinked microparticles. The obtained microparticles were evaluated for morphology and size by SEM and drug loading level. Tamoxifen physical state inside the microparticles was analysed by DSC and IR analysis. Rheological analysis was performed to detected chemical interaction between the drug and the polysaccharide. Results: Tamoxifen citrate salt exists in two polymorphic forms, metastable form A, stable form B. Commercial product was metastable form A. The microscopic observation of the obtained microparticles revealed a size in 1-3 m range, which is considered proper to be taken up by M cells of Peyer’s patches. Following the spray-drying process, TMX was found in an amorphous state. The rheological analysis, detecting polyelectrolite electroviscous effect, demonstrated the TMX/alginate interaction leading to a suitable drug loading level and to a drug immobilisation within the microparticles. Conclusions: Tamoxifen citrate salt is widely used as the primary hormonal therapy for metastatic estrogen receptor-positive breast cancer. However, side effects include endometrial pathologies, liver cancer and ocular effects. The designed microparticles could be taken up by Peyer’s patches and translocate the drug to the lymphatic system, so avoiding the first-pass metabolism and enzymatic degradation from cytosolic enzymes of the epithelial cells. Therefore, an improved TMX bioavailability could lead to a decrease of the therapeutic dose and, consequently, of the side effects

In vivo investigation of an intragastric floating multi-unit system

Oral floating devices are made to be retained in the stomach for a long time assuring a slow delivery of the drug above its absorption site providing increased and more reproducible bioavailability.An air compartment multiple-unit system able to float immediately on being placed into artificial gastric fluid and obtainable by a simple technological approach was developed. The designed units are constituted by coated beads composed of a calcium alginate core separated by an air compartment from a calcium alginate/polyvinylalcohol membrane .The “in vivo” assay demonstrated the actual floatability of the units on the gastric content and a prolongation of the gastric residence time (GRT) in comparison with non floating units in different feeding conditions .In the present study, the floating system was loaded with riboflavin-5’-phosphate having absorption sites which are mainly limited to the upper region of the small intestine.The “in vivo” study was carried out by administering to healthy subjects floating and control systems according to a randomized crossover design on different separate sessions.Riboflavin urinary excretion values among subjects alternatively fed after a light meal or after a heavy meal were measured for 24 h.Riboflavin cumulative urinary excretion data, indicative of bioavailability values, were statistically analized by the one-way ANOVA method. The values estimated for the floating system resulted higher than those for the control system, with a more significant difference if formulations with similar “in vitro” release patterns were considered.This finding may suggest the possibility to achieve increased bioavailability by dosing riboflavin through a floating system

Gastroretentive multiple-unit delivery system in the treatment of Helicobacter pylori infection

Calcium alginate floating units loaded with tetracycline were prepared by means an interfacial crosslinking reaction of sodium alginate drops with calcium ions and freeze-drying providing porous units with apparent density values less than that of the gastric juice. Such a technological approach has simplified a previous manufacture for the development of calcium alginate air-compartment floating units which showed actual buoyancy properties and prolonged Gastric Residence Time (GRT) in human trials in fed conditions. The formulation study provided a sample with optimum property in terms of drug loading level for the treatment of Helicobacter pylori infection