88 research outputs found

    Stable Field Emitters for a Miniature X-ray Tube Using Carbon Nanotube Drop Drying on a Flat Metal Tip

    Get PDF
    Stable carbon nanotube (CNT) field emitters for a vacuum-sealed miniature X-ray tube have been fabricated. The field emitters with a uniform CNT coating are prepared by a simple drop drying of a CNT mixture solution that is composed of chemically modified multi-walled CNTs, silver nanoparticles, and isopropyl alcohol on flat tungsten tips. A highly thermal- and electrical-conductive silver layer strongly attaches CNTs to the tungsten tips. Consequently, the field emitters exhibit good electron emission stability: continuous electron emission of around 100 ÎŒA at 2.3 V/ÎŒm has stably lasted over 40 h even at non-high vacuum ambient (~10−3 Pa)

    Chemical vapour deposition synthetic diamond: materials, technology and applications

    Full text link
    Substantial developments have been achieved in the synthesis of chemical vapour deposition (CVD) diamond in recent years, providing engineers and designers with access to a large range of new diamond materials. CVD diamond has a number of outstanding material properties that can enable exceptional performance in applications as diverse as medical diagnostics, water treatment, radiation detection, high power electronics, consumer audio, magnetometry and novel lasers. Often the material is synthesized in planar form, however non-planar geometries are also possible and enable a number of key applications. This article reviews the material properties and characteristics of single crystal and polycrystalline CVD diamond, and how these can be utilized, focusing particularly on optics, electronics and electrochemistry. It also summarizes how CVD diamond can be tailored for specific applications, based on the ability to synthesize a consistent and engineered high performance product.Comment: 51 pages, 16 figure

    Stage-I osteochondritis dissecans versus normal variants of ossification in the knee in children

    Full text link
    Background: Juvenile osteochondritis dissecans (OCD) has a better prognosis than the adult type. Objective : We postulated that the excellent prognosis of juvenile OCD could be explained, at least in part, by the erroneous diagnosis of some developmental variants of ossification as stage-I OCD. Materials and methods : Knee MRIs of 38 children, ages 7.5–17.7 years (mean and median age 13 years), were retrospectively reviewed to look for features that might separate normal variants of ossification from stage-I OCD. These included age, gender, site, configuration of the lesion, residual cartilaginous model and presence of edema. Results : Twenty-three patients (32 condyles) had ossification defects with intact articular cartilage suggestive of stage-I lesions. No stage-II lesions were seen in the posterior femoral condyles. Accessory ossification centers were seen in 11/16 posterior condyles and 3/16 central condyles. Spiculation of existing ossification was seen in 12/16 posterior condylar lesions and 1/16 central condyles. There was a predominance of accessory ossifications and spiculations in the patients with 10% or greater residual cartilaginous model. No edema signal greater than diaphyseal red-marrow signal was seen in the posterior condyles. Clinical follow-up ranged from 0.5 to 38 months, with clinical improvement in 22 out of 23 patients. Conclusion : Inclusion of normal variants in the stage-I OCD category might explain, in part, the marked difference in published outcome between the juvenile and adult forms of OCD. Ossification defects in the posterior femoral condyles with intact overlying articular cartilage, accessory ossification centers, spiculation, residual cartilaginous model, and lack of bone-marrow edema are features of developmental variants rather than OCD.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46719/1/247_2005_Article_1507.pd

    Pattern recognition receptors in immune disorders affecting the skin.

    Get PDF
    Contains fulltext : 109004.pdf (publisher's version ) (Open Access)Pattern recognition receptors (PRRs) evolved to protect organisms against pathogens, but excessive signaling can induce immune responses that are harmful to the host. Putative PRR dysfunction is associated with numerous immune disorders that affect the skin, such as systemic lupus erythematosus, cryopyrin-associated periodic syndrome, and primary inflammatory skin diseases including psoriasis and atopic dermatitis. As yet, the evidence is often confined to genetic association studies without additional proof of a causal relationship. However, insight into the role of PRRs in the pathophysiology of some disorders has already resulted in new therapeutic approaches based on immunomodulation of PRRs

    A guide for reporting the results of population pharmacokinetic analyses: A Swedish perspective

    No full text
    Population pharmacokinetic analyses are frequently part of regulatory submissions and are mainly used to provide information on special populations (effects of age, renal impairment, etc) and drug-drug interactions. A varying standard of population analysis reports has been received at the Medical Products Agency in Sweden, some very good and some unassessable. In the latter case, it may be that it is a report of an inadequate analysis or may be a report of a perfectly acceptable analysis, but too little detail has been provided in the report for the conclusions reached to be properly assessed. A sufficient level of detail must be present in these reports in order for them to be assessable and to allow the conclusions reached to be incorporated into the summary of product characteristics. The report should specify the goal(s) of the analysis, describe in detail the origin and nature of the data, clearly describe the model-building process, include a range of goodness of fit (GOF) plots to support decisions made during the model-building process, and demonstrate that the final model is a good description of the data. The use of color in GOF plots is encouraged so that key features are easily visible. Covariate effects in the final model should be clearly presented and their clinical relevance discussed. In the case of many covariates in the final model, it may be useful to perform some simulations to illustrate the effect of various covariate combinations for a series of different “typical” subjects
    • 

    corecore