1,176 research outputs found

    Tuning Pd-nanoparticle@MIL-101(Cr) catalysts for tandem reductive amination

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    The authors thank the EPSRC (EP/L505079/1), SASOL Technology UK and the University of St Andrews for funding.The versatility of MOFs as highly porous Lewis acidic supports for precious metal nanoparticles has been exploited for one-pot tandem reductive amination catalysis. MIL-101(Cr) loaded with Pd nanoparticles ca. 3 nm in size at 0.2–1 wt% has been used to catalyse the reaction of 4′-fluoroacetophenone with benzylamine under 10 bar of H2 to give the secondary amine, 4′-fluoro-α-methyl-N-phenylmethylbenzenemethanamine. For the highest Pd loading, major hydrogenolysis of the secondary amine occurs in a second tandem reaction, but by changing the ratio of Pd to Lewis acidic Cr3+ active sites it is possible to tune the catalytic selectivity to the desired 2° amine product. An empirical kinetic analysis was performed to demonstrate this active site complementarity.Publisher PDFPeer reviewe

    Outcome of all-inside second-generation meniscal repair: Minimum five-year follow-up

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    BACKGROUND: Meniscal repair and preservation are the goal, when possible, of the treatment of meniscal injury. Current research on second-generation all-inside repair systems has been limited to a maximum of three years of follow-up. The purpose of this study was to evaluate the mid-term clinical success (at more than five years) of meniscal repair performed with a second-generation all-inside repair device, both as an isolated procedure and with a concomitant anterior cruciate ligament (ACL) reconstruction. METHODS: This is a retrospective review of patients who underwent meniscal repair with use of the all-inside FAST-FIX Meniscal Repair System (Smith & Nephew Arthroscopy, Andover, Massachusetts) from December 1999 to January 2007. Eighty-three meniscal repairs (in eighty-one patients) were identified, and follow-up data were obtained for seventy-five (90%). Twenty-six (35%) of the meniscal repairs were performed as isolated procedures. Clinical failure was defined as repeat surgical intervention involving resection or revision repair. Clinical outcomes were also assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score, and the Marx activity score. RESULTS: The minimum duration of follow-up was five years (average, seven years). Twelve patients (16%) had failure of the meniscal repair, at an average of forty-seven months (range, fifteen to ninety-five months). The data did not offer enough statistical evidence, at alpha = 0.05, to establish a difference in average patient age, patient sex, or number of sutures utilized between successful repairs and failures. There was no difference in the failure rate between isolated repairs (12%; 95% confidence interval [CI]: −0.76% to 23.76%) and those performed with concurrent ACL reconstruction (18%; 95% CI: 7.47% to 29.13%), and the average time to failure was similar between these two groups (48.1 months versus 46.6 months, p = 0.939). Postoperative KOOS and IKDC outcome scores were also similar between the groups. CONCLUSIONS: This report of mid-term follow-up results of primary second-generation all-inside meniscal repair demonstrates its effectiveness both as an isolated procedure and when it is performed with concurrent ACL reconstruction. After a minimum of five years of follow-up, 84% of the patients continued to demonstrate successful repair. Treatment success was further supported by favorable results on patient-based outcome measures. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

    WISE Brown Dwarf Binaries: The Discovery of a T5+T5 and a T8.5+T9 System

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    The multiplicity properties of brown dwarfs are critical empirical constraints for formation theories, while multiples themselves provide unique opportunities to test evolutionary and atmospheric models and examine empirical trends. Studies using high-resolution imaging cannot only uncover faint companions, but they can also be used to determine dynamical masses through long-term monitoring of binary systems. We have begun a search for the coolest brown dwarfs using preliminary processing of data from the Wide-field Infrared Survey Explorer and have confirmed many of the candidates as late-type T dwarfs. In order to search for companions to these objects, we are conducting observations using the Laser Guide Star Adaptive Optics system on Keck II. Here we present the first results of that search, including a T5 binary with nearly equal mass components and a faint companion to a T8.5 dwarf with an estimated spectral type of T9

    Connecting Model Species to Nature: Predator-Induced Long-Term Sensitization in Aplysia californica

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    Previous research on sensitization in Aplysia was based entirely on unnatural noxious stimuli, usually electric shock, until our laboratory found that a natural noxious stimulus, a single sublethal lobster attack, causes short-term sensitization. We here extend that finding by demonstrating that multiple lobster attacks induce long-term sensitization (\u3e= 24 h) as well as similar, although not identical, neuronal correlates as observed after electric shock. Together these findings establish long-and short-term sensitization caused by sublethal predator attack as a natural equivalent to sensitization caused by artificial stimuli

    Language Matters: Developing Educators’ Expertise for English Learners in Linguistically Diverse Communities

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    The population of English learners (ELs) continues to grow in schools across the United States and around the world. In this article, we share one urban university’s collaborative approach to building educational capacity for cultural and linguistic diversity through professional development efforts that brought together stakeholders from classrooms, schools, communities, and districts. This grant-funded project aimed to build educator expertise to effectively support and positively influence students’ language development and disciplinary learning. Grounded in sociocultural theory, we used an apprenticeship framework of teacher development, strategically planning and implementing collaborative capacity building efforts to foster learning across individual, interpersonal, and institutional planes. In this paper, we share the results of professional development efforts across three years of this project, drawing from observation, interview, and focus group data. Findings indicate that classroom-, school-, and district-level educators developed knowledge of discipline-specific language development, pedagogical skills for effective EL teaching and learning, and leadership abilities to positively shape institutional responses to their culturally and linguistically diverse student populations. Implications focus on fostering teacher professionalism through bottom-up development of EL-specific expertise and expanded opportunities for leadership

    Ultra-compact and ultra-broadband hybrid plasmonic-photonic vertical coupler with high coupling efficiency, directivity, and polarisation extinction ratio

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    An ultra-compact, ultra-broadband vertical coupler for dense photonic integrated circuits is reported with a 1.07×0.62μm2 wavelength-scale footprint. This hybrid plasmonic-photonic coupler uses a unique two-plane plasmonic nanoantenna array on a silicon-on-insulator waveguide. The in- and out-of-plane interference of the multipole moments and dual-feed nanoantennas results in efficient, unidirectional coupling. Finite-element simulations show that, for a 0.8μm diameter Gaussian beam, the maximum coupling efficiency (CE) is −3.4dB across the telecommunication C-, L- and U-bands with a 3-dB bandwidth of 230nm. The CE is>9dB higher than recently reported ultra-compact plasmonic couplers. The maximum directivity and polarisation extinction ratio across the C- to U-bands are 9.2 and 24.1dB, respectively. Finally, as an out-coupler, it has a vertical directivity of >8.5dB, enabling its use for vertical optical interconnects between two vertically separated circuits

    Identifying moderating factors during the preschool period in the development of borderline personality disorder: A prospective longitudinal analysis

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    BACKGROUND: Despite a growing literature detailing early childhood risk factors for borderline personality disorder (BPD), few studies have examined moderating factors that might mitigate or exacerbate the effects of those risk factors. The current study examined whether three preschool-age characteristics-impulsivity, emotional lability, and initiative-taking-moderated the relationship between known preschool-age risk factors and adolescent BPD symptoms. METHODS: We performed multilevel modeling analyses in a sample (n = 151) from the Preschool Depression Study, a prospective longitudinal study with assessments from preschool through adolescence. Preschool risk factors included adverse childhood experiences, internalizing symptoms, and externalizing symptoms measured with parent clinical interviews. Preschool moderating factors were assessed via parent report and observational coding of temperament and behavior. The Borderline Personality Features Scale for Children measured BPD symptoms in adolescence. RESULTS: We found that observed initiative-taking moderated the relationship between preschool internalizing symptoms and adolescent BPD symptoms (b = 0.57, p = .011) and moderated the relationship between preschool externalizing symptoms and adolescent BPD symptoms (b = 1.42, p = .013). Greater initiative-taking was associated with lower BPD risk for children with high internalizing or externalizing symptoms. Conversely, for children with low internalizing or externalizing symptoms, greater initiative-taking was associated with increased BPD risk. CONCLUSIONS: We identify a potential moderating factor in BPD development, offer novel targets for screening and intervention, and provide a framework for using early childhood observational assessments in BPD research. Our findings suggest the need for future research on early moderating factors in BPD development, which could inform early childhood interventions targeting those factors to mitigate the effects of potentially less malleable risk factors
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