110 research outputs found
MR-Imaging of Meniscal Substitution
More than a century ago, the menisci were considered to be the functionless remains of a leg muscle. Gradually the usefulness and function of the meniscus was investigated and proven, and the link between total meniscectomy, radiographic osteoarthritis and reduced knee function was made. Subsequently, partial meniscectomy was introduced in the clinical practice. However, the frequency of symptomatic knee osteoarthritis was not substantially lowered. Therefore, meniscal repair was introduced for younger individuals with traumatic meniscus lesions with a good healing potential. Later on in the development process, the quest for meniscal replacement strategies arose. The introduction of allogenic, xenogenic and artificial materials followed in research and clinical settings. Nowadays, a lot of research is conducted on meniscal substitutes, because meniscal injuries are a very common problem in the general population. The imaging of the meniscus is running parallel to this evolution. With the development of magnetic resonance imaging (MRI), the meniscus could be perfectly visualized. A lot of studies were published on imaging of the normal meniscus, and subsequently meniscal pathology on MRI was investigated. In the current literature, a growing number of papers describe the MRI findings in artificial meniscus replacements
Adapted Morris Water Maze protocol to prevent interference from confounding motor deficits on cognitive functioning
Purpose/aim of the study: Cognitive functioning in the Morris Water Maze (MWM) is assumed to be reflected by path length. In this study, the interference of motor deficits, as a confounding factor on cognitive functioning, was assessed by means of a lateralization study with hemicerebellectomized (HCX) mice. This model is characterized by motor deficits restricted to the lesion side, allowing comparison within the model itself (left vs. right), rather than the effect of the manipulation on this measure (experimental vs. control).Materials and methods: Spatial learning was assessed after left or right hemicerebellectomy in adult mice by means of two MWM designs in which the location of the starting positions was altered for one condition in the adapted (Adap) MWM experiment, hypothesizing that motor impairments ipsilateral to the lesion side result in a difference in path length.Results: When the starting positions were equal for both conditions in the traditional (Trad) MWM experiment, path length during the acquisition phase and spatial memory were more affected for the left HCX, while these effects disappeared after mirroring the starting positions in the Adap MWM, implying that motor phenotype and corresponding increase in task difficulty are responsible for the contradictory results in the Trad MWM experiment.Conclusion: The differences found in the latter experiment were circumvented in the adapted MWM protocol, and therefore, excluding the motor deficit as a confounding factor on cognitive MWM parameters
What are sources of carbon lock-in in energy-intensive industry? A case study into Dutch chemicals production
Keeping global mean temperature rise well below 2 °C requires deep emission reductions in all industrial sectors, but several barriers inhibit such transitions. A special type of barrier is carbon lock-in, defined as a process whereby various forms of increasing returns to adoption inhibit innovation and the competitiveness of low-carbon alternatives, resulting in further path dependency. Here, we explore potential carbon lock-in in the Dutch chemical industry via semi-structured interviews with eleven key actors. We find that carbon lock-in may be the result of (i) technological incompatibility between deep emission reduction options over time, (ii) system integration in chemical clusters, (iii) increasing sunk costs as firms continue to invest in incremental improvements in incumbent installations, (iv) governmental policy inconsistency between targets for energy efficiency and deep emission reductions, and (v) existing safety routines and standards. We also identify barriers that do not have the self-reinforcing character of lock-in, but do inhibit deep emission reductions. Examples include high operating costs of low-carbon options and low risk acceptance by capital providers and shareholders. Rooted in the Dutch policy setting, we discuss policy responses for avoiding carbon lock-in and overcoming barriers based on the interviews, such as transition plans for individual industries and infrastructure subsidies
Laser Ablation Efficiency, Laser Ablation Speed, and Laser Energy Consumption During Lithotripsy: What Are They and How Are They Defined? A Systematic Review and Proposal for a Standardized Terminology
Context
Laser performance for lithotripsy is currently reported using units of measurement such as J/mm3, mm3/J, mm3/s, s/mm3, and mm3/min. However, there are no current standardized definitions or terminology for these metrics. This may lead to confusion when assessing and comparing different laser systems.
Objective
The primary objective was to summarize outcome values and corresponding terminology from studies on laser lithotripsy performance using stone volume in relation to time or energy. The secondary objective was to propose a standardized terminology for reporting laser performance metrics.
Evidence acquisition
A systematic review of the literature was conducted using the search string (“j*/mm3” OR “mm3/j*” OR “mm3/s*” OR “s*/mm3” OR “mm3/min*” OR “min*/mm3” AND “lithotripsy”) on Scopus, Web of Science, Embase, and PubMed databases. Study selection, data extraction, and quality assessment were performed independently by two authors.
Evidence synthesis
A total of 28 studies were included, covering holmium:yttrium-aluminum-garnet (Ho:YAG), MOSES, and thulium fiber laser (TFL) technologies. Laser energy consumption values reported for the studies ranged from 2.0 – 43.5 J/mm3 in vitro and from 2.7 – 47.8 J/mm3 in vivo, translating to laser ablation efficiency of 0.023 – 0.500 mm3/J and 0.021 – 0.370 mm3/J, respectively. Laser ablation speeds ranged from 0.3 – 8.5 mm3/s in vivo, translating to lasing time consumption of 0.12 – 3.33 s/mm3. Laser efficacy ranged from 4.35 – 51.7 mm3/min in vivo. There was high heterogeneity for the terminology used to describe laser performance for the same metrics.
Conclusions
The range of laser performance metric values relating stone volume to energy or time is wide, with corresponding differing terminology. We propose a standardized terminology for future studies on laser lithotripsy, including laser ablation efficiency (mm3/J), laser ablation speed (mm3/s), and laser energy consumption (J/mm3). Laser efficacy (mm3/min) is proposed as a broader term that is based on the total operative time, encompassing the whole technique using the laser.
Patient summary
We reviewed studies to identify the units and terms used for laser performance when treating urinary stones. The review revealed a wide range of differing units, outcomes, and terms. Therefore, we propose a standardized terminology for future studies on laser stone treatment.
Keywords
UreteroscopyPercutaneous nephrolithotomyLaserStone diseaseLithotripsyPerformanceUrolithiasi
Embry-Riddle Fly Paper 1943-01-15
https://commons.erau.edu/fly-paper/1159/thumbnail.jp
Potential release of aluminum and other metals by food-grade aluminum foil used for skin allograft cryo preservation
Since 1991, the skin bank of the Queen Astrid Military Hospital uses food-grade aluminum foil as a primary support for storing cryo preserved human donor skin (511 donors). The possible release of heavy metals into the cryo preservation media (30% (v/v) glycerol in physiological water) and the possible impact this release could have on the quality of the cryo preserved donor skin was evaluated. Aluminum was the principal detection target. Possible contaminants of the aluminum foil as such (arsenic, cadmium, chromium and lead) were also investigated. The evaluation was set up after a Belgian Competent Authority inspection remark. Aluminum was detected at a concentration of 1.4 mg/l, arsenic and lead were not detected, while cadmium and chromium were detected in trace element quantities. An histological analysis revealed no differences between cryo preserved and fresh donor skin. No adverse reactions in patients, related to the presence of aluminum or heavy metal traces, were reported since the introduction of the cryo preserved donor skin in our burn wound centre
Phase II study of helical tomotherapy in the multidisciplinary treatment of oligometastatic colorectal cancer
<p>Abstract</p> <p>Background</p> <p>Complete metastasectomy provides a real chance for long-term survival in patients with oligometastatic colorectal cancer (CRC). For inoperable patients, we evaluated in this study intensity-modulated and image-guided radiotherapy (IMRT-IGRT) by helical tomotherapy.</p> <p>Methods</p> <p>Twenty-four CRC patients with ≤ 5 metastases were enrolled, receiving a dose of 50 Gy in fractions of 5 Gy. No limitations concerning dimension or localization of the metastases were imposed. Whole body PET-CT was performed at baseline and 3 months after the initiation of RT to evaluate the metabolic response rate according to PET Response Criteria in Solid Tumors (PERCIST) version 1.0.</p> <p>Results</p> <p>A total of 53 metastases were treated. Seventeen patients (71%) received previously ≥ 1 line of chemotherapy for metastatic disease, displaying residual (n = 7) or progressive (n = 10) metabolic active oligometastatic disease at time of inclusion. Most common sites were the lung, liver and lymphnodes. One patient (4%) experienced grade 3 dysphagia. Twenty-two patients were evaluated by post-treatment PET-CT. Twelve patients achieved a complete (n = 6) or partial (n = 6) metabolic response, resulting in an overall metabolic response rate of 55%. At a median follow-up of 10 months, 7 patients (29%) are in remission, of which 5 received previous chemotherapy with residual oligometastatic disease at time of inclusion. The actuarial 1-year local control, progression-free survival, and overall survival were 54%, 14% and 78%.</p> <p>Conclusions</p> <p>Helical tomotherapy delivering 10 fractions of 5 Gy resulted in a metabolic response rate of 55%, and appeared to be attractive as consolidation of inoperable oligometastatic disease after effective chemotherapy.</p> <p>Trial registration</p> <p>Eudract 2008-008300-40; <a href="http://www.clinicaltrials.gov/ct2/show/NCT00807313">NCT00807313</a></p
Glycerol treatment as recovery procedure for cryopreserved human skin allografts positive for bacteria and fungi
Human donor skin allografts are suitable and much used temporary biological (burn) wound dressings. They prepare the excised wound bed for final autografting and form an excellent substrate for revascularisation and for the formation of granulation tissue. Two preservation methods, glycerol preservation and cryopreservation, are commonly used by tissue banks for the long-term storage of skin grafts. The burn surgeons of the Queen Astrid Military Hospital preferentially use partly viable cryopreserved skin allografts. After mandatory 14-day bacterial and mycological culture, however, approximately 15% of the cryopreserved skin allografts cannot be released from quarantine because of positive culture. To maximize the use of our scarce and precious donor skin, we developed a glycerolisation-based recovery method for these culture positive cryopreserved allografts. The inactivation and preservation method, described in this paper, allowed for an efficient inactivation of the colonising bacteria and fungi, with the exception of spore-formers, and did not influence the structural and functional aspects of the skin allografts
Feeder layer- and animal product-free culture of neonatal foreskin keratinocytes: improved performance, usability, quality and safety
Since 1987, keratinocytes have been cultured at the Queen Astrid Military Hospital. These keratinocytes have been used routinely as auto and allografts on more than 1,000 patients, primarily to accelerate the healing of burns and chronic wounds. Initially the method of Rheinwald and Green was used to prepare cultured epithelial autografts, starting from skin samples from burn patients and using animal-derived feeder layers and media containing animal-derived products. More recently we systematically optimised our production system to accommodate scientific advances and legal changes. An important step was the removal of the mouse fibroblast feeder layer from the cell culture system. Thereafter we introduced neonatal foreskin keratinocytes (NFK) as source of cultured epithelial allografts, which significantly increased the consistency and the reliability of our cell production. NFK master and working cell banks were established, which were extensively screened and characterised. An ISO 9001 certified Quality Management System (QMS) governs all aspects of testing, validation and traceability. Finally, as far as possible, animal components were systematically removed from the cell culture environment. Today, quality controlled allograft production batches are routine and, due to efficient cryopreservation, stocks are created for off-the-shelf use. These optimisations have significantly increased the performance, usability, quality and safety of our allografts. This paper describes, in detail, our current cryopreserved allograft production process
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