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Microneedle Patch-Mediated Treatment of Bacterial Biofilms
No full textCurrent treatments of bacterial biofilms are limited by the poor penetration of antibiotics through their physical barrier as well as significant off-target toxicity of antibiotics and the induction of antibiotic resistance. Here we report a microneedle patch-mediated treatment for the effective elimination of biofilms by penetrating the biofilm and specifically delivering antibiotics to regions of active growth. We fabricated patches with self-dissolvable microneedles and needle tips loaded with chloramphenicol (CAM)-bearing and gelatinase-sensitive gelatin nanoparticles (CAM@GNPs). During the microneedle patch-mediated treatment, arrays of 225 microneedles simultaneously penetrate the biofilm matrix. Once inside, the microneedles dissolve and uniformly release CAM@GNPs into the surrounding area. In response to the gelatinase produced by the active bacterial community, the CAM@GNPs disassemble and release CAM into these active regions of the biofilm. Moreover, CAM@GNPs exhibited minimal off-target toxicity compared to direct CAM administration, which in turn favors wound healing. Importantly, we found that our microneedle-mediated treatment is more effective in treating Vibrio vulnificus biofilms than drug in free solution. We believe this new treatment strategy can be used to improve the delivery of a wide range of antimicrobial agents to biofilm-contaminated sites
Biased recommendations from biased and unbiased experts
No full textWhen can an expert be trusted to provide useful advice? We experimentally test a simplified recommendation game where an expert recommends one of two actions to a decision maker who may take either action or instead pursue an outside option. Consistent with predictions from the cheap talk literature, we find that decision makers partially discount recommendations for the action a biased expert favors, but that recommendations can still be persuasive in that they reduce the chance of the outside option. If the decision maker is uncertain whether the expert is biased toward an action, biased experts lie even more, while unbiased experts follow a political correctness strategy of recommending the opposite action so as to be more persuasive by appearing unbiased. Even if experts are known to be unbiased, experts pander by recommending the action that the decision maker already favors, and decision makers discount the recommendation. The results highlight that transparency of expert incentives can improve communication, but need not ensure unbiased advice
Better Together: How Faculty Development and Assessment Can Join Forces to Improve Student Learning
No full textDeveloping metacognitive skills through class activities: what makes students use metacognitive skills?
No full textMetacognitive skills can improve with appropriate instruction, however, educators may not be familiar with these methods of teaching. This study explores what factors influenced students to implement metacognitive skills and how students perceived the purposefully designed metacognitive activity in a high school classroom in South Korea. 252 students were involved in the study and a survey and focus group interviews were employed for the data collection. A linear regression analysis revealed that perceived task values predicted the use of metacognitive skills.Athematic analysis of the interviews showed the possibility of transferring the metacognitive skills to new contexts, and the benefits of student-teacher interactions in developing their metacognitive skills. Implications of the results for research and the instructional design of the metacognitive activities are discussed
The Use of Dress in Objectification Research
Get PDFTo objectify another person is to dehumanize and treat that person as an object. Objectification has interested dress scholars, and some objectification scholars have acknowledged that clothing and bodies act to facilitate or resist objectification. Research purposes were to determine the extent to which dress had been used to evoke objectification in experiments when objectification was an outcome and to determine whether internal validity had been correctly established. Experimental objectification research was content analyzed using descriptive statistics. A database search resulted in 80 refereed empirical research articles containing 91 experiments. Dress was used to evoke objectification in 57 experiments; yet, many provided no rationale for using dress stimuli or conducted manipulation checks or stimulus pretests. These practices call into question the validity of research results and may explain inconsistent results. Opportunities for dress scholars and recommendations for teaching and for research best practices are offered
The Pricing and Performance of Supercharged IPOs
Get PDFThis study examines a new form of initial public offerings, “supercharged” IPOs, where a firm organized pre-IPO as a pass-through entity undergoes a series of transactions that steps-up the adjusted tax basis of the IPO firm’s assets. This step-up imposes tax liabilities on pre-IPO owners but also creates significant future tax benefits for the firm; the average anticipated deferred tax asset is 13 per share) for our sample of supercharged IPO firms. Pursuant to tax receivable agreements, supercharged IPO firms pay a large portion of these tax benefits to pre-IPO owners as they are realized in the future. Future firm performance must be sufficiently strong for the IPO firm and the pre-IPO owners to realize the future tax benefits created by the supercharged transaction structure. We hypothesize and provide evidence of higher IPO offer prices and stronger future performance for supercharged IPO firms relative to traditional IPO firms
Intramolecular Hydrogen Bonding Facilitates Electrocatalytic Reduction of Nitrite in Aqueous Solutions
No full textThe nitride ligand in the iron(IV) complex, PhB(MesIm)Fe N reacts with excess HSiPh to afford PhB(MesIm)Fe(-H)(SiHPh) as the major product, which has been structurally and spectroscopically characterized. The bulkier silane HaSiPh provides the iron(II) amido complex PhB(MesIm)FeN(H)(SiHPh) as the initial product of the reaction, with excess HSiPh affording diamagnetic PhB(MesIm)Fe(-H)(SiPh) as the major product. The unobserved iron(II) hydride PhB(MesIm)Fe-H is implicated as an intermediate in this reaction, as suggested by the results of the reaction between the iron(II) amido PhB(MesIm)FeN(H)tBu and HSiPh, which provides PhB(MesIm)Fe(H)(-H)(Si(NHtBu)Ph) as the sole product
Ecohydrologic separation alters interpreted hydrologic stores and fluxes in a headwater mountain catchment
No full textRecent studies have demonstrated that compartmentalized pools of water preferentially supply either plant transpiration (poorly mobile water) or streamflow and groundwater (highly mobile water) in some catchments, a phenomenon referred to as ecohydrologic separation. The omission of processes accounting for ecohydrologic separation in standard applications of hydrological models is expected to influence estimates of water residence times and plant water availability. However, few studies have tested this expectation or investigated how ecohydrologic separation alters interpretations of stores and fluxes of water within a catchment. In this study, we compare two rainfall‐runoff models that integrate catchment‐scale representations of transport, one that incorporates ecohydrologic separation and one that does not. The models were developed for a second‐order watershed at the H.J. Andrews Experimental Forest (Oregon, USA), the site where ecohydrologic separation was first observed, and calibrated against multiple years of stream discharge and chloride concentration. Model structural variations caused mixed results for differences in calibrated parameters and differences in storage between reservoirs. However, large differences in catchment storage volumes and fluxes arise when considering only mobile water. These changes influence interpreted residence times for streamflow‐generating water, demonstrating the importance of ecohydrologic separation in catchment‐scale water and solute transport
One-shot learning of view-invariant object representations in newborn chicks
No full textCan newborn brains perform one-shot learning? To address this question, we reared newborn chicks in strictly controlled environments containing a single view of a single object, then tested their object recognition performance across 24 uniformly-spaced viewpoints. We found that chicks can build view-invariant object representations from a single view of an object: a case of one-shot learning in newborn brains. Chicks can also build the same viewinvariant object representation from different views of an object, showing that newborn brains converge on common object representations from different sets of sensory inputs. Finally, by rearing chicks with larger numbers of object views, we found that chicks develop enhanced recognition for familiar views. These results illuminate the earliest stages of object recognition, revealing (1) powerful one-shot learning that builds invariant object representations from the first views of an object and (2) view-based learning that enriches object representations, producing enhanced recognition for familiar views
Extended Prophylaxis With Nevirapine Does Not Affect Growth in HIV-Exposed Infants
No full textBackground: Effects of prolonged nevirapine prophylaxis exposure on growth among HIV-exposed uninfected (HEU) infants are unknown. This study examines the impact of extended nevirapine prophylaxis from 6 weeks to 6 months on the growth of HEU infants followed for 18 months and also identifies correlates of incident wasting, stunting, underweight, and low head circumference in the HPTN 046 trial. Methods: Intention-to-treat analysis examined the effect of extended nevirapine exposure on: weight-for-age Z-score, length-for-age Z-score, weight-for-length Z-score, and head circumference-for-age Z-score. Multivariable linear mixed-effects and Cox proportional hazard models were used to compare growth outcomes between the study arms and identify correlates of incident adverse growth outcomes, respectively. Results: Compared to placebo, extended prophylactic nevirapine given daily from 6 weeks to 6 months did not affect growth in HEU breastfeeding (BF) infants over time (treatment × time: P > 0.05). However, overall growth declined over time (time effect: P < 0.01) when compared with WHO general population norms. Male sex was associated with higher risk of all adverse growth outcomes (P < 0.05), whereas short BF duration was associated with wasting (P = 0.03). Maternal antiretroviral therapy exposure was protective against underweight (P = 0.02). Zimbabwe tended to have worse growth outcomes especially stunting, compared to South Africa, Uganda and Tanzania (P < 0.05). Conclusions: It is reassuring that prolonged exposure to nevirapine for prevention-of-mother-to-child HIV transmission does not restrict growth. However, targeted interventions are needed to improve growth outcomes among at-risk HEU infants (i.e., male sex, short BF duration, lack of maternal antiretroviral therapy exposure, and resident in Zimbabwe)