Lotte Vermeulen

Challenging the other: exploring the role of opponent gender in digital game competition for female players

Abstract The present study investigated the effect of opponent gender on the game experience of female players. Concretely, it looked into skill perception and player emotions of women in same gender and cross-gender game competition. We set up a 2×2×2 (male vs. female opponent×low vs. high competitive women×lost vs. won game) experimental design in which women were instructed to play against a proclaimed male and female competitor. Unknowingly, however, participants played against an AI, which was configured to produce a winning and a losing condition for each opponent by manipulating difficulty. Results indicated that opponent gender only had an effect on perceived stress, which was higher with male opponents. Moreover, players evaluated their own gaming skills as lower and the skills of presumed male opponents as higher when they thought they were playing against men. Importantly, our results also showed that the above described pattern for self-perceived skills and perceived opponent skills was modulated by trait competitiveness with a larger effect size for low competitive women. Overall, this study illustrates that gender dynamics affect the play experience of women in cross-gender gaming competition. Implications and suggestions for future research are discussed.

Design of smart GE11-PLGA/PEG-PLGA blend nanoparticulate platforms for parenteral administration of hydrophilic macromolecular drugs: synthesis, preparation and in vitro/ex vivo characterization.

Active drug targeting and controlled release of hydrophilic macromolecular drugs represent crucial points in designing efficient polymeric drug delivery nanoplatforms. In the present work EGFR-targeted polylactide-co-glycolide (PLGA) nanoparticles were made by a blend of two different PLGA-based polymers. The first, GE11-PLGA, in which PLGA was functionalized with GE11, a small peptide and EGFR allosteric ligand, able to give nanoparticles selective targeting features. The second polymer was a PEGylated PLGA (PEG-PLGA) aimed at improving nanoparticles hydrophilicity and stealth features. GE11 and GE11-PLGA were custom synthetized through a simple and inexpensive method. The nanoprecipitation technique was exploited for the preparation of polymeric nanoparticles composed by a 1:1weight ratio between GE11-PLGA and PEG-PLGA, obtaining smart nanoplatforms with proper size for parenteral administration (143.9±5.0nm). In vitro cellular uptake in EGFR-overexpressing cell line (A549) demonstrated an active internalization of GE11-functionalized nanoparticles. GE11-PLGA/PEG-PLGA blend nanoparticles were loaded with Myoglobin, a model hydrophilic macromolecule, reaching a good loading (2.42% respect to the theoretical 4.00% w/w) and a prolonged release over 60days. GE11-PLGA/PEG-PLGA blend nanoparticles showed good in vitro stability for 30days in physiological saline solution at 4°C and for 24h in pH 7.4 or pH 5.0 buffer at 37°C respectively, giving indications about potential storage and administration conditions. Furthermore ex vivo stability study in human plasma using fluorescence Single Particle Tracking (fSPT) assessed good GE11-PLGA/PEG-PLGA nanoparticles dimensional stability after 1 and 4h. Thanks to the versatility in polymeric composition and relative tunable nanoparticles features in terms of drug incorporation and release, GE11-PLGA/PEG-PLGA blend NPs can be considered highly promising as smart nanoparticulate platforms for the treatment of diseases characterized by EGFR overexpression by parenteral administration .

“I Play So I Am?” A Gender Study into Stereotype Perception and Genre Choice of Digital Game Players

Stereotypes in game culture are still inhibiting the freedom of female players. This survey study aims to gain insight into these practices by looking at gaming stereotypes on two different, yet interrelated, levels. First, we inquire into perceptions of gamers regarding gender-related and general gamer stereotypes and how these relate to playing frequency. Second, genre choice is investigated in light of player’s gender and how this is associated with play motivations. Results suggest that high frequency female players disagree the most with gender-related stereotypical beliefs and that these women are more strongly drawn towards specific gaming genres than men.

Playing under threat. Examining stereotype threat in female game players

The present study assesses the impact of stereotype threat on how women experience digital gaming in an evaluative context. By means of a controlled lab experiment, this study tested the effects of reinforcing stereotypical information suggesting that women are less competent players versus the effects of countering this stereotype. In doing so, game leaderboard scores were manipulated distinguishing between Stereotype Neutral (high scores without gender cues), Stereotype Boost (female-dominated high scores) and Stereotype Threat (male-dominated high scores) conditions. Results indicated that gamer identity, trait competitiveness, and playing habits modulate the experience of social identity threat. Performance and affective responses elicited by the Stereotype Threat Condition were more negatively affected in case of strongly identified gamers, highly competitive women, and/or avid players when compared with the other conditions. However, virtually no differences were observed when comparing the Stereotype Neutral and Stereotype Boost conditions. Overall, the present study demonstrates the existence of the stereotype threat mechanism and how this undermines the game experience of female players within digital game culture. Investigating stereotype threat in the context of women playing games.Womens gamer identity and play habits as important moderators for threat effects.Worse performance in threat condition compared to neutral and boost conditions.Increased negative affect in threat condition compared to neutral and boost conditions.Female role modeling does not guarantee improved performance or affective responses.

Endosomal Size and Membrane Leakiness Influence Proton Sponge-Based Rupture of Endosomal Vesicles

In gene therapy, endosomal escape represents a major bottleneck since nanoparticles often remain entrapped inside endosomes and are trafficked toward the lysosomes for degradation. A detailed understanding of the endosomal barrier would be beneficial for developing rational strategies to improve transfection and endosomal escape. By visualizing individual endosomal escape events in live cells, we obtain insight into mechanistic factors that influence proton sponge-based endosomal escape. In a comparative study, we found that HeLa cells treated with JetPEI/pDNA polyplexes have a 3.5-fold increased endosomal escape frequency compared to ARPE-19 cells. We found that endosomal size has a major impact on the escape capacity. The smaller HeLa endosomes are more easily ruptured by the proton sponge effect than the larger ARPE-19 endosomes, a finding supported by a mathematical model based on the underlying physical principles. Still, it remains intriguing that even in the small HeLa endosomes, <10% of the polyplex-containing endosomes show endosomal escape. Further experiments revealed that the membrane of polyplex-containing endosomes becomes leaky to small compounds, preventing effective buildup of osmotic pressure, which in turn prevents endosomal rupture. Analysis of H1299 and A549 cells revealed that endosomal size determines endosomal escape efficiency when cells have comparable membrane leakiness. However, at high levels of membrane leakiness, buildup of osmotic pressure is no longer possible, regardless of endosomal size. Based on our findings that both endosomal size and membrane leakiness have a high impact on proton sponge-based endosomal rupture, we provide important clues toward further improvement of this escape strategy.

Effect of video lag on laparoscopic surgery: correlation between performance and usability at low latencies.

Few telesurgery studies assess the impact of latency on user experience, low latencies are often not studied despite evidence of negative effects, and some studies recruit inexperienced subjects instead of surgeons without evidence that latency affects both groups similarly.

Quantifying the average number of nucleic acid therapeutics per nanocarrier by Single Particle Tracking microscopy

Nucleic acid biopharmaceuticals are being investigated as potential therapeutics. They need to be incorporated into a biocompatible carrier so as to overcome several biological barriers. Rational development of suitable nanocarriers requires high-quality characterization techniques. While size, concentration, and stability can be very well measured these days, even in complex biological fluids, a method to accurately quantify the number of nucleic acid therapeutics encapsulated in nanocarriers is still missing. Here we present a method, based on concentration measurements with single particle tracking microscopy, with which it is possible to directly measure the number of plasmid DNA molecules per nanoparticle, referred to as the plasmid/NP ratio. Using DOTAP/DOPE liposomes as a model carrier, we demonstrate the usefulness of the method by investigating the influence of various experimental factors on the plasmid/NP ratio. We find that the plasmid/NP ratio is inversely proportional with the size of the pDNA and that the plasmid/NP decreases when lipoplexes are prepared at lower concentrations of pDNA and nanocarrier, with values ranging from 6.5 to 3 plasmid/NP. Furthermore, the effect of pre- and post-PEGylation of lipoplexes was examined, finding that pre-PEGylation results in a decreased plasmid/NP ratio, while post-PEGylation did not alter the plasmid/NP ratio. These proof-of-concept experiments show that single particle tracking offers an extension of the nanoparticle characterization toolbox and is expected to aid in the efficient development of nanoformulations for nucleic acid-based therapies.

Photothermally Triggered Endosomal Escape and Its Influence on Transfection Efficiency of Gold-Functionalized JetPEI/pDNA Nanoparticles

Plasmonic nanoparticles for drug delivery have attracted increasing interest over the last few years. Their localized surface plasmon resonance causes photothermal effects on laser irradiation, which allows for delivering drugs in a spatio-temporally controlled manner. Here, we explore the use of gold nanoparticles (AuNP) as carriers for pDNA in combination with pulsed laser irradiation to induce endosomal escape, which is currently considered to be one of the major bottlenecks in macromolecular drug delivery on the intracellular level. In particular, we evaluate nanocomplexes composed of JetPEI (polyethylenimine)pDNA and 10 nm AuNP, which do not exhibit endosomal escape by themselves. After incubating HeLa cells with these complexes, we evaluated endosomal escape and transfection efficiency using low- and high-energy laser pulses. At low laser energy heat is produced by the nanocomplexes, while, at higher laser energy, explosive vapour nanobubbles (VNB) are formed. We investigated the ability of heat transfer and VNB formation to induce endosomal escape and we examine the integrity of pDNA cargo after inducing both photothermal effects. We conclude that JetPEI/pDNA/AuNP complexes are unable to induce meaningful transfection efficiencies because laser treatment causes either dysfunctionality of the cargo when VNB are formed or forms too small pores in the endosomal membrane to allow pDNA to escape in case of heating. We conclude that laser-induced VNB is the most suitable to induce effective pDNA endosomal escape, but a different nanocomplex structure will be required to keep the pDNA intact.