93 research outputs found

    Diamond Bur Cutting Efficiency of Dental Zirconia

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    Objectives: To monitor the rate of diamond bur cutting through sintered yttria stabilized zirconia. Through this observation, we intend to determine which bur(s) exhibit the greatest cutting efficiency and if a decline exists over time.;Methods: Seven dental diamond burs were used in an air-turbine hand piece to cut sintered Yttria Stabilized Zirconia blocks (3Y-TZP) at a constant 0.9N force for five minutes. The distance traveled was measured by a Linear Variable Differential Transformer (LVDT) and recorded per time by a data acquisition device. Time was divided into 100-second intervals for comparison. Individual effects of bur, time periods, and depth on cutting efficiency were evaluated. Combined effect of bur and time periods was also evaluated.;Results: Statistically significant differences were found between bur, time period and depth on bur cutting efficiency of 3Y-TZP. Combined effect of bur and time period did not demonstrate a significant difference. Burs with medium, coarse, and super coarse diamond particles exhibited greater cutting efficiency of sintered 3Y-TZP than burs with fine diamond particles. Cutting efficiency of all burs was significantly greater within the initial 100 second cutting time period.;Conclusions: For removal of 3Y-TZP crowns intraorally via sectioning, the results of this study suggest it is best to use a diamond bur with medium, coarse or super coarse particle grit size and limit its use to 100 seconds in order to maximize cutting efficiency. The super coarse diamond had the greatest cutting efficiency throughout the 5-minute evaluation period. Future studies are needed to evaluate cutting efficiency after low temperature degradation (LTD) and surface manipulations on 3Y-TZP in order to duplicate exposure to the oral environment, and expanding the testing time beyond 5 minutes to determine if and when a second significant difference in cutting efficiency occurs

    How Knowledge Workers Think Generative AI Will (Not) Transform Their Industries

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    Generative AI is expected to have transformative effects in multiple knowledge industries. To better understand how knowledge workers expect generative AI may affect their industries in the future, we conducted participatory research workshops for seven different industries, with a total of 54 participants across three US cities. We describe participants' expectations of generative AI's impact, including a dominant narrative that cut across the groups' discourse: participants largely envision generative AI as a tool to perform menial work, under human review. Participants do not generally anticipate the disruptive changes to knowledge industries currently projected in common media and academic narratives. Participants do however envision generative AI may amplify four social forces currently shaping their industries: deskilling, dehumanization, disconnection, and disinformation. We describe these forces, and then we provide additional detail regarding attitudes in specific knowledge industries. We conclude with a discussion of implications and research challenges for the HCI community.Comment: 40 pages, 5 tables, 6 figure

    A Scalable Biomimetic Synthesis of Resveratrol Dimers and Systematic Evaluation of their Antioxidant Activities

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    An efficient synthetic route to the resveratrol oligomers quadrangularin A and pallidol is reported. It features a scalable biomimetic oxidative dimerization that proceeds in excellent yield and with complete regioselectivity. A systematic evaluation of the natural products and their synthetic precursors as radical‐trapping antioxidants has revealed that, contrary to popular belief, this mode of action is unlikely to account for their observed biological activity.Hartnäckigkeit zahlt sich aus: Eine kurze Synthese der Resveratrol‐Oligomere Quadrangularin A und Pallidol macht sich die Stabilität der von 2,6‐Di‐tert‐butylphenol abgeleiteten Radikal‐ und der Chinonmethid‐Zwischenstufe zunutze. Untersuchungen dieser Verbindungen als antioxidative Radikalfänger ergaben, dass diese Eigenschaft höchstwahrscheinlich nicht die Ursache ihrer beobachteten biologischen Aktivität ist.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110868/1/3825_ftp.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110868/2/ange_201409773_sm_miscellaneous_information.pd

    Maturation of heterogeneity in afferent synapse ultrastructure in the mouse cochlea

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    Auditory nerve fibers (ANFs) innervating the same inner hair cell (IHC) may have identical frequency tuning but different sound response properties. In cat and guinea pig, ANF response properties correlate with afferent synapse morphology and position on the IHC, suggesting a causal structure-function relationship. In mice, this relationship has not been fully characterized. Here we measured the emergence of synaptic morphological heterogeneities during maturation of the C57BL/6J mouse cochlea by comparing postnatal day 17 (p17, ∼3 days after hearing onset) with p34, when the mouse cochlea is mature. Using serial block face scanning electron microscopy and three-dimensional reconstruction we measured the size, shape, vesicle content, and position of 70 ribbon synapses from the mid-cochlea. Several features matured over late postnatal development. From p17 to p34, presynaptic densities (PDs) and post-synaptic densities (PSDs) became smaller on average (PDs: 0.75 to 0.33; PSDs: 0.58 to 0.31 μ

    Intranasal Acellular Pertussis Vaccine Provides Mucosal Immunity and Protects Mice from Bordetella Pertussis

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    Current acellular pertussis vaccines fall short of optimal protection against the human respiratory pathogen Bordetella pertussis resulting in increased incidence of a previously controlled vaccine- preventable disease. Natural infection is known to induce a protective mucosal immunity. Therefore, in this study, we aimed to use acellular pertussis vaccines to recapitulate these mucosal immune responses. We utilized a murine immunization and challenge model to characterize the efficacy of intranasal immunization (IN) with DTaP vaccine or DTaP vaccine supplemented with curdlan, a known Th1/Th17 promoting adjuvant. Protection from IN delivered DTaP was compared to protection mediated by intraperitoneal injection of DTaP and whole-cell pertussis vaccines. We tracked fluorescently labeled DTaP after immunization and detected that DTaP localized preferentially in the lungs while DTaP with curdlan was predominantly in the nasal turbinates. IN immunization with DTaP, with or without curdlan adjuvant, resulted in anti-B. pertussis and anti-pertussis toxin IgG titers at the same level as intraperitoneally administered DTaP. IN immunization was able to protect against B. pertussis challenge and we observed decreased pulmonary pro-inflammatory cytokines, neutrophil infiltrates in the lung, and bacterial burden in the upper and lower respiratory tract at day 3 post challenge. Furthermore, IN immunization with DTaP triggered mucosal immune responses such as production of B. pertussis-specific IgA, and increased IL-17A. Together, the induction of a mucosal immune response and humoral antibody-mediated protection associated with an IN administered DTaP and curdlan adjuvant warrant further exploration as a pertussis vaccine candidate formulation

    Intranasal acellular pertussis vaccine provides mucosal immunity and protects mice from <i>Bordetella pertussis</i>

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    Current acellular pertussis vaccines fall short of optimal protection against the human respiratory pathogen Bordetella pertussis resulting in increased incidence of a previously controlled vaccine- preventable disease. Natural infection is known to induce a protective mucosal immunity. Therefore, in this study, we aimed to use acellular pertussis vaccines to recapitulate these mucosal immune responses. We utilized a murine immunization and challenge model to characterize the efficacy of intranasal immunization (IN) with DTaP vaccine or DTaP vaccine supplemented with curdlan, a known Th1/Th17 promoting adjuvant. Protection from IN delivered DTaP was compared to protection mediated by intraperitoneal injection of DTaP and whole-cell pertussis vaccines. We tracked fluorescently labeled DTaP after immunization and detected that DTaP localized preferentially in the lungs while DTaP with curdlan was predominantly in the nasal turbinates. IN immunization with DTaP, with or without curdlan adjuvant, resulted in anti-B. pertussis and anti-pertussis toxin IgG titers at the same level as intraperitoneally administered DTaP. IN immunization was able to protect against B. pertussis challenge and we observed decreased pulmonary pro-inflammatory cytokines, neutrophil infiltrates in the lung, and bacterial burden in the upper and lower respiratory tract at day 3 post challenge. Furthermore, IN immunization with DTaP triggered mucosal immune responses such as production of B. pertussis-specific IgA, and increased IL-17A. Together, the induction of a mucosal immune response and humoral antibody-mediated protection associated with an IN administered DTaP and curdlan adjuvant warrant further exploration as a pertussis vaccine candidate formulation.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula
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