218 research outputs found

    Dibenzimidazolium Salts and Their Interactions with 1,5-dinaphtho-38-crown-10

    Get PDF
    The use of imidazolium salts in mechanically interlocked molecules, like pseudorotaxanes, is of interest because they can be functionalized with side arms that allow for coordination chemistry. It has been previously shown that tetraakylbenzobisimidazolium salts successfully thread through crown ethers, such as 15DN38C10 or BPP34C10, to form pseudorotaxanes. As an extension of the results that were gathered about this novel template, it was our goal to explore the degree to which larger imidazolium salts interact with such crown ethers. This research focused on the interactions between 15DN38C10 and dibenzimidazolium cations that were tetra-substituted with methyl groups, butyl groups, and benzyl groups, respectively. These interactions were assessed using 1H NMR spectroscopy

    Dibenzimidazolium Salts and Their Interactions with 1,5-dinaphtho-38-crown-10

    Get PDF
    The use of imidazolium salts in mechanically interlocked molecules, like pseudorotaxanes, is of interest because they can be functionalized with side arms that allow for coordination chemistry. It has been previously shown that tetraakylbenzobisimidazolium salts successfully thread through crown ethers, such as 15DN38C10 or BPP34C10, to form pseudorotaxanes. As an extension of the results that were gathered about this novel template, it was our goal to explore the degree to which larger imidazolium salts interact with such crown ethers. This research focused on the interactions between 15DN38C10 and dibenzimidazolium cations that were tetra-substituted with methyl groups, butyl groups, and benzyl groups, respectively. These interactions were assessed using 1H NMR spectroscopy

    Automatic recognition of schwa variants in spontaneous Hungarian speech

    Get PDF
    This paper analyzes the nature of the process involved in optional vowel reduction in Hungarian, and the acoustic structure of schwa variants in spontaneous speech. The study focuses on the acoustic patterns of both the basic realizations of Hungarian vowels and their realizations as neutral vowels (schwas), as well as on the design, implementation, and evaluation of a set of algorithms for the recognition of both types of realizations from the speech waveform. The authors address the question whether schwas form a unified group of vowels or they show some dependence on the originally intended articulation of the vowel they stand for. The acoustic study uses a database consisting of over 4,000 utterances extracted from continuous speech, and recorded from 19 speakers. The authors propose methods for the recognition of neutral vowels depending on the various vowels they replace in spontaneous speech. Mel-Frequency Cepstral Coefficients are calculated and used for the training of Hidden Markov Models. The recognition system was trained on 2,500 utterances and then tested on 1,500 utterances. The results show that a neutral vowel can be detected in 72% of all occurrences. Stressed and unstressed syllables can be distinguished in 92% of all cases. Neutralized vowels do not form a unified group of phoneme realizations. The pronunciation of schwa heavily depends on the original articulation configuration of the intended vowel

    A Mouse Model of Post-Arthroplasty Staphylococcus aureus Joint Infection to Evaluate In Vivo the Efficacy of Antimicrobial Implant Coatings

    Get PDF
    Post-arthroplasty infections represent a devastating complication of total joint replacement surgery, resulting in multiple reoperations, prolonged antibiotic use, extended disability and worse clinical outcomes. As the number of arthroplasties in the U.S. will exceed 3.8 million surgeries per year by 2030, the number of post-arthroplasty infections is projected to increase to over 266,000 infections annually. The treatment of these infections will exhaust healthcare resources and dramatically increase medical costs.To evaluate novel preventative therapeutic strategies against post-arthroplasty infections, a mouse model was developed in which a bioluminescent Staphylococcus aureus strain was inoculated into a knee joint containing an orthopaedic implant and advanced in vivo imaging was used to measure the bacterial burden in real-time. Mice inoculated with 5x10(3) and 5x10(4) CFUs developed increased bacterial counts with marked swelling of the affected leg, consistent with an acute joint infection. In contrast, mice inoculated with 5x10(2) CFUs developed a low-grade infection, resembling a more chronic infection. Ex vivo bacterial counts highly correlated with in vivo bioluminescence signals and EGFP-neutrophil fluorescence of LysEGFP mice was used to measure the infection-induced inflammation. Furthermore, biofilm formation on the implants was visualized at 7 and 14 postoperative days by variable-pressure scanning electron microscopy (VP-SEM). Using this model, a minocycline/rifampin-impregnated bioresorbable polymer implant coating was effective in reducing the infection, decreasing inflammation and preventing biofilm formation.Taken together, this mouse model may represent an alternative pre-clinical screening tool to evaluate novel in vivo therapeutic strategies before studies in larger animals and in human subjects. Furthermore, the antibiotic-polymer implant coating evaluated in this study was clinically effective, suggesting the potential for this strategy as a therapeutic intervention to combat post-arthroplasty infections

    One-Stage Synovectomies Result in Improved Short-Term Outcomes Compared to Two-Stage Synovectomies of Diffuse-Type Tenosynovial Giant Cell Tumor (D-TGCT) of the Knee: A Multicenter, Retrospective, Cohort Study

    Get PDF
    Diffuse-type tenosynovial giant cell tumors\u27 (D-TGCTs) intra- and extra-articular expansion about the knee often necessitates an anterior and posterior surgical approach to facilitate an extensive synovectomy. There is no consensus on whether two-sided synovectomies should be performed in one or two stages. This retrospective study included 191 D-TGCT patients from nine sarcoma centers worldwide to compare the postoperative short-term outcomes between both treatments. Secondary outcomes were rates of radiological progression and subsequent treatments. Between 2000 and 2020, 117 patients underwent one-stage and 74 patients underwent two-stage synovectomies. The maximum range of motion achieved within one year postoperatively was similar (flexion 123-120°, p = 0.109; extension 0°, p = 0.093). Patients undergoing two-stage synovectomies stayed longer in the hospital (6 vs. 4 days, p \u3c 0.0001). Complications occurred more often after two-stage synovectomies, although this was not statistically different (36% vs. 24%, p = 0.095). Patients treated with two-stage synovectomies exhibited more radiological progression and required subsequent treatments more often than patients treated with one-stage synovectomies (52% vs. 37%, p = 0.036) (54% vs. 34%, p = 0.007). In conclusion, D-TGCT of the knee requiring two-side synovectomies should be treated by one-stage synovectomies if feasible, since patients achieve a similar range of motion, do not have more complications, but stay for a shorter time in the hospital

    Posterior fossa tumours in childhood: Associated speech and language disorders post-surgery

    Get PDF
    Six children aged between 6 and 16 years who had undergone surgery for the removal of a posterior fossa tumour were assessed at least one year postoperatively to determine the incidence and severity of any associated speech or language deficits. Five males and one female were included in the sample. The subjects were administered a battery of speech/language assessments including: a language screening test, an articulation test, a dysarthria assessment and a perceptual speech analysis. The results indicated that dysarthria and/or language impairment occurs in some cases subsequent to surgical removal of posterior fossa tumours. The occurrence of muteness immediately post-surgery would appear to indicate a poor prognosis for speech abilities. A possible link between the occurrence of long term language disabilities in these children and post-surgical radiotherapy is documented

    Dibenzimidazolium salts and their interactions with 1,5-dinaphtho-38-crown-10

    No full text
    corecore