642 research outputs found

    Zero kinetic energy-pulsed field ionization and resonance enhanced multiphoton ionization photoelectron spectroscopy: Ionization dynamics of Rydberg states in HBr

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    The results of rotationally resolved resonance enhanced multiphoton ionization photoelectron spectroscopy and zero kinetic energy‐pulsed field ionization studies on HBr via various rotational levels of the F^ 1Δ_2 and f^ 3Δ_2 Rydberg states are reported. These studies lead to an accurate determination of the lowest ionization threshold as 94 098.9±1 cm^(−1). Observed rotational and spin–orbit branching ratios are compared to the results of ab initio calculations. The differences between theory and experiment highlight the dominant role of rotational and spin–orbit interactions for the dynamic properties of the high‐n Rydberg states involved in the pulsed field ionization process

    Impaction grafting and cement in acetabular revision arthroplasty

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    Tissue adhesives for meniscus tear repair:an overview of current advances and prospects for future clinical solutions

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    Contains fulltext : 171814.pdf (publisher's version ) (Open Access)Menisci are crucial structures in the knee joint as they play important functions in load transfer, maintaining joint stability and in homeostasis of articular cartilage. Unfortunately, ones of the most frequently occurring knee injuries are meniscal tears. Particularly tears in the avascular zone of the meniscus usually do not heal spontaneously and lead to pain, swelling and locking of the knee joint. Eventually, after a (partial) meniscectomy, they will lead to osteoarthritis. Current treatment modalities to repair tears and by that restore the integrity of the native meniscus still carry their drawbacks and a new robust solution is desired. A strong tissue adhesive could provide such a solution and could potentially improve on sutures, which are the current gold standard. Moreover, a glue could serve as a carrier for biological compounds known to enhance tissue healing. Only few tissue adhesives, e.g., Dermabond((R)) and fibrin glue, are already successfully used in clinical practice for other applications, but are not considered suitable for gluing meniscus tissue due to their sub-optimal mechanical properties or toxicity. There is a growing interest and research field focusing on the development of novel polymer-based tissue adhesives, but up to now, there is no material specially designed for the repair of meniscal tears. In this review, we discuss the current clinical gold standard treatment of meniscal tears and present an overview of new developments in this field. Moreover, we discuss the properties of different tissue adhesives for their potential use in meniscal tear repair. Finally, we formulate recommendations regarding the design criteria of material properties and adhesive strength for clinically applicable glues for meniscal tears

    Impaction grafting and cement in acetabular revision arthroplasty

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    Impaction grafting and cemented acetabular revision

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    Environmental and nutrient conditions influence fucoxanthin productivity of the marine diatom Phaeodactylum tricornutum grown on palm oil mill effluent

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    Palm oil mill effluent (POME) is a type of wastewater posing large problems when discharged in the environment. Yet, due to its high nutrient content, POME may offer opportunities for algal growth and subsequent harvesting of high-value products. The marine diatom Phaeodactylum tricornutum is a potential feedstock diatom for bioactive compounds such as the carotenoid fucoxanthin, which has been shown to have pharmaceutical applications. The aim of this paper was to evaluate the growth and fucoxanthin productivity of P. tricornutum grown on POME, as a function of light intensity, temperature, salinity, and nutrient enrichment. High-saturating irradiance (300molphotonsm(-2)s(-1)) levels at 25 degrees C showed highest growth rates but decreased the fucoxanthin productivity of P. tricornutum. Box-Behnken response surface methodology revealed that the optimum fucoxanthin productivity was influenced by temperature, salinity, and the addition of urea. Nutrient enrichment by phosphorus did not enhance cell density and fucoxanthin productivity, while urea addition was found to stimulate both. We conclude that POME wastewater, supplemented with urea, can be considered as the potential medium for P. tricornutum to replace commercial nutrients while producing high amounts of fucoxanthin.</p

    Enhancement of C-phycocyanin productivity by Arthrospira platensis when growing on palm oil mill effluent in a two-stage semi-continuous cultivation mode

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    Palm oil mill effluent (POME) is well known as agricultural wastewater that has a high potential as a medium for microalgal growth due to its high macro- and micronutrient content. The cyanobacterium Arthrospira platensis is considered as a species with a high C-phycocyanin (C-PC) content which is important for fine chemical and pharmaceutical applications. However, cultivation of A. platensis on POME to produce economically feasible amounts of C-PC has not been well explored. For this, environmental, nutritional, and cultivation modes (batch, semi-continuous) were varied to optimize C-PC productivity when cultivated at various POME concentrations. Arthrospira platensis was found to grow well on POME. Highest biomass and C-PC concentrations were found on 30–100% POME. Central composite rotatable design (CCRD) response surface methodology demonstrated that C-PC productivity was influenced by urea addition at the optimum salinity. The highest C-PC productivity was found on 100% POME during semi-continuous cultivation, while the addition of phosphorus and urea did not significantly improve C-PC productivity. By applying semi-continuous cultivation with 50% POME at the first stage and 100% POME at the second stage, a similarly high C-PC productivity (4.08 ± 1.3 mg L−1 day−1) was achieved as compared with (artificial) Zarrouk medium during batch cultivation. We conclude that, when using a two-stage semi-continuous cultivation process, A. platensis can produce economically feasible amounts of C-PC when cultivated on 100% POME
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