Dropwise Condensation of Low Surface Tension Fluids on Omniphobic Surfaces

Compared to the significant body of work devoted to surface engineering for promoting dropwise condensation heat transfer of steam, much less attention has been dedicated to fluids with lower interfacial tension. A vast array of low-surface tension fluids such as hydrocarbons, cryogens, and fluorinated refrigerants are used in a number of industrial applications, and the development of passive means for increasing their condensation heat transfer coefficients has potential for significant efficiency enhancements. Here we investigate condensation behavior of a variety of liquids with surface tensions in the range of 12 to 28 mN/m on three types of omniphobic surfaces: smooth oleophobic, re-entrant superomniphobic, and lubricant-impregnated surfaces. We demonstrate that although smooth oleophobic and lubricant-impregnated surfaces can promote dropwise condensation of the majority of these fluids, re-entrant omniphobic surfaces became flooded and reverted to filmwise condensation. We also demonstrate that on the lubricant-impregnated surfaces, the choice of lubricant and underlying surface texture play a crucial role in stabilizing the lubricant and reducing pinning of the condensate. With properly engineered surfaces to promote dropwise condensation of low-surface tension fluids, we demonstrate a four to eight-fold improvement in the heat transfer coefficient.National Science Foundation (U.S.). Graduate Research Fellowship ProgramNational Science Foundation (U.S.) (CAREER Award 0952564)MIT Energy Initiativ

Prevalence of Errors in Anaphylaxis in Kids (PEAK): A Multicenter Simulation-Based Study

Background Multi-institutional, international practice variation of pediatric anaphylaxis management by health care providers has not been reported. Objective To characterize variability in epinephrine administration for pediatric anaphylaxis across institutions, including frequency and types of medication errors. Methods A prospective, observational, study using a standardized in situ simulated anaphylaxis scenario was performed across 28 health care institutions in 6 countries. The on-duty health care team was called for a child (patient simulator) in anaphylaxis. Real medications and supplies were obtained from their actual locations. Demographic data about team members, institutional protocols for anaphylaxis, timing of epinephrine delivery, medication errors, and systems safety issues discovered during the simulation were collected. Results Thirty-seven in situ simulations were performed. Anaphylaxis guidelines existed in 41% (15 of 37) of institutions. Teams used a cognitive aid for medication dosing 41% (15 of 37) of the time and 32% (12 of 37) for preparation. Epinephrine autoinjectors were not available in 54% (20 of 37) of institutions and were used in only 14% (5 of 37) of simulations. Median time to epinephrine administration was 95 seconds (interquartile range, 77-252) for epinephrine autoinjector and 263 seconds (interquartile range, 146-407.5) for manually prepared epinephrine (P = .12). At least 1 medication error occurred in 68% (25 of 37) of simulations. Nursing experience with epinephrine administration for anaphylaxis was associated with fewer preparation (P = .04) and administration (P = .01) errors. Latent safety threats were reported by 30% (11 of 37) of institutions, and more than half of these (6 of 11) involved a cognitive aid. Conclusions A multicenter, international study of simulated pediatric anaphylaxis reveals (1) variation in management between institutions in the use of protocols, cognitive aids, and medication formularies, (2) frequent errors involving epinephrine, and (3) latent safety threats related to cognitive aids among multiple sites

Go Run That Code: Developing Trust in Trainees to Lead Pediatric Resuscitations

Background: Cardiopulmonary resuscitation is a high-acuity, low-frequency event. Studies show gaps in trainee confidence and experience. Resuscitation has been proposed as an entrustable professional activity for general pediatric and pediatric critical care trainees. Supervisor entrustment of trainees to lead pediatric resuscitations can be challenging given the characteristics of this professional activity. Previous studies investigating the development of trust have not focused on pediatric resuscitation or the impact of clinical context or models of supervision. Purpose: To describe trust development in pediatric resuscitation highlighting the impact of context and supervision model. Methods: Qualitative, multi-institutional study using semi-structured interviews of trainees and supervisors. Interviews elucidated roles and expectations of trainees and supervisors involved in pediatric resuscitation teams and factors impacting entrustment. Results: Ten interviews were conducted, 5 trainees and 5 supervisors. Thematic analysis to achieve saturation conducted by two coders. Themes about trust development differed significantly between supervisors and trainees. Context affected the development of trust. No significant difference was noted across different supervision models. Conclusions: The development of trust in trainees to lead pediatric resuscitations is complex and multi-faceted with clinical context an important factor. Training programs may be able to incorporate curricular and institutional changes to enhance trust development

Pediatric pyogenic sacroiliitis and osteomyelitis

Pyogenic sacroiliitis for 1-2% of all cases of septic arthritis with less than 200 cases reported in the English literature since the beginning of the twentieth century. Cultures of joint fluid usually grow Staphylococcus aureus. Prognosis is excellent; however, diagnosis may be difficult due to rarity of disease and non-specific signs, symptoms, and physical findings. Magnetic resonance imaging has been found to be the most useful imaging modality in diagnosis. Most reported cases required prolonged antimicrobial therapy of six to nine weeks. Presented here are two children with pyogenic sacroiliitis managed at a tertiary-care, university hospital and review of the literature on this relatively rare diagnosis

Moving beyond end-to-end path information to optimize cdn performance

Replicating content across a geographically distributed set of servers and redirecting clients to the closest server in terms of latency has emerged as a common paradigm for improving client performance. In this paper, we analyze latencies measured from servers in Google’s content distribution network (CDN) to clients all across the Internet to study the effectiveness of latency-based server selection. Our main result is that redirecting every client to the server with least latency does not suffice to optimize client latencies. First, even though most clients are served by a geographically nearby CDN node, a sizeable fraction of clients experience latencies several tens of milliseconds higher than other clients in the same region. Second, we find that queueing delays often override the benefits of a client interacting with a nearby server. To help the administrators of Google’s CDN cope with thes

Transportation-Related Guidelines for Hip Spica Application and Subsequent Discharge Planning

Hip spica casts are a common method to treat trauma or hip dysplasia for children aged ~6 months to 4 or 5 years. The cast is typically applied with the lower extremities positioned to achieve satisfactory fracture reduction and/or joint stability while avoiding a reduction in blood flow to the hip joint. A number of studies have observed that some spica cast positions can present a challenge to safely transport the child home. This is due to the posterior cast geometry which is typically not congruent with the child’s car seat. In the current study, a series of transportation options were evaluated to identify seats that accommodate a hip spica cast

Disulfiram is a DNA demethylating agent and inhibits prostate cancer cell growth

Background The clinical success of the nucleoside analogs 5-aza-cytidine (5-azaC) and 5-aza-2′deoxycytidine (5-aza-dC) as DNA methyltransferase (DNMT) inhibitors has spurred interest in the development of non-nucleoside inhibitors with improved pharmacologic and safety profiles. Because DNMT catalysis features attack of cytosine bases by an enzyme thiol group, we tested whether disulfiram (DSF), a thiol-reactive compound with known clinical safety, demonstrated DNMT inhibitory activity. Methods Inhibition of DNMT1 activity by DSF was assessed using methyltransferase activity assays with recombinant DNMT1. Next, prostate cancer cell lines were exposed to DSF and assessed for: i) reduction of global 5-methyl cytosine (5meC) content using liquid chromatography/tandem mass spectrometry (LC-MS/MS); ii) gene-specific promoter demethylation by methylation-specific PCR (MSP); and iii) gene-reactivation by real-time RT-PCR. DSF was also tested for growth inhibition using prostate cancer cell lines propagated in vitro in cell culture and in vivo as xenografts in nude mice. Results Disulfiram showed a dose-dependent inhibition of DNMT1 activity on a hemimethylated DNA substrate. In prostate cancer cells in culture, DSF exposure led to reduction of global genomic 5meC content, increase in unmethylated APC and RARB gene promoters, and associated re-expression of these genes, but did not significantly alter prostate-specific antigen (PSA) expression. DSF significantly inhibited growth and clonogenic survival of prostate cancer cell lines in culture and showed a trend for reduced growth of prostate cancer xenografts. Conclusions Disulfiram is a non-nucleoside DNMT1 inhibitor that can reduce global 5meC content, reactivate epigenetically silenced genes, and significantly inhibit growth in prostate cancer cell lines. © 2010 Wiley-Liss, Inc