Self-trapped exciton state in Si nanocrystals revealed by induced absorption

We report results of time-resolved induced absorption (IA) spectroscopy on Si nanocrystals (Si NCs) embedded in a SiO 2 matrix. In line with theoretical modeling, the IA amplitude decreases with probing photon energy, however only until a certain threshold value. For larger photon energies, an increase of IA is observed. This unexpected behavior is interpreted in terms of the self-trapped exciton state whose formation in Si NCs was put forward some time ago based on theoretical considerations. Here, we present a direct experimental confirmation of this supposition. © 2012 American Physical Society

Celecoxib: considerations regarding its potential disease-modifying properties in osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive loss of articular cartilage, subchondral bone sclerosis, osteophyte formation, and synovial inflammation, causing substantial physical disability, impaired quality of life, and significant health care utilization. Traditionally, non-steroidal anti-inflammatory drugs (NSAIDs), including selective cyclooxygenase (COX)-2 inhibitors, have been used to treat pain and inflammation in OA. Besides its anti-inflammatory properties, evidence is accumulating that celecoxib, one of the selective COX-2 inhibitors, has additional disease-modifying effects. Celecoxib was shown to affect all structures involved in OA pathogenesis: cartilage, bone, and synovium. As well as COX-2 inhibition, evidence indicates that celecoxib also modulates COX-2-independent signal transduction pathways. These findings raise the question of whether celecoxib, and potentially other coxibs, is more than just an anti-inflammatory and analgesic drug. Can celecoxib be considered a disease-modifying osteoarthritic drug? In this review, these direct effects of celecoxib on cartilage, bone, and synoviocytes in OA treatment are discussed

Carrier dynamics in Si nanocrystals in an SiO<inf>2</inf> matrix investigated by transient light absorption

We report on investigations of optical carrier generation in silicon nanocrystals embedded in an SiO2 matrix. Carrier relaxation and recombination processes are monitored by means of time-resolved induced absorption, using a conventional femtosecond pump-probe setup for samples containing different average sizes of nanocrystals (dNC = 2.5-5.5 nm). The electron-hole pairs generated by the pump pulse are probed by a second pulse over a broad spectral range (Eprobe = 0.95-1.35 or 1.6-3.25 eV), by which information on excited states is obtained. Under the same excitation conditions, we observe that the induced absorption intensity in the near-infrared range is a factor of ∼10 higher than in the visible range. To account for these observations, we model the spectral dependence of the induced absorption signal using an empirical sp3d5s* tight-binding technique, by which the spectrum can be well reproduced up to a certain threshold. For probe photon energies above this threshold (dependent on nanocrystal size), the induced absorption signal is found to feature a long-standing component, whereas the induced absorption signal for probe photon energies below this value vanishes within 0.5 ns. We explain this by self-trapping of excitons on surface-related states. © 2013 American Physical Society

Health-related quality of life and functional ability in patients with early arthritis during remission steered treatment: results of the IMPROVED study

INTRODUCTION: The aim of this study was to investigate patient reported outcomes (PROs) of functional ability and health related quality of life (HRQoL) in patients with early (rheumatoid) arthritis during one year of remission steered treatment. METHODS: In this study, 610 patients with early rheumatoid arthritis (RA) or undifferentiated arthritis (UA) were treated with methotrexate (MTX) and tapered high dose of prednisone. Patients in early remission (Disease Activity Score (DAS) <1.6 after 4 months) tapered prednisone to zero and when in persistent remission, also tapered MTX. Patients not in early remission were randomized to either MTX + hydroxychloroquine + sulphasalazine + prednisone (arm 1) or to MTX + adalimumab (arm 2). Every 4 months, patients filled out the Health Assessment Questionnaire (HAQ) and the McMaster Toronto Arthritis Patient Preference Questionnaire (MACTAR), the Short Form 36 (SF-36) and visual analogue scales (VAS). Change scores were compared between treatment groups. The association with achieving remission was analyzed using linear mixed models. RESULTS: During year 1, patients who achieved early remission had the most improvement in PROs with scores comparable to the general population. Patients in the randomization arms showed less improvement. Scores were comparable between the arms. There was a significant association between achieving remission and scores of HAQ, MACTAR and physical HRQoL. CONCLUSIONS: In early arthritis, PROs of functional ability and HRQoL after one year of remission steered treatment reach normal values in patients who achieved early remission. In patients not in early remission, who were randomized to two strategy arms, PROs improved less, with similar scores in both treatment arms. TRIAL REGISTRATIONS: ISRCTN11916566 and EudraCT2006-006186-1

Interviews for the assessment of long-term incapacity for work: a study on adherence to protocols and principles

<p>Abstract</p> <p>Background</p> <p>Assessments for long-term incapacity for work are performed by Social Insurance Physicians (SIPs) who rely on interviews with claimants as an important part of the process. These interviews are susceptible to bias. In the Netherlands three protocols have been developed to conduct these interviews. These protocols are expert- and practice-based. We studied to what extent these protocols are adhered to by practitioners.</p> <p>Methods</p> <p>We compared the protocols with one another and with the ICF and the biopsychosocial approach. The protocols describe semi-structured interviews with comparable but not identical topics. All protocols prescribe that the client's opinion on his capacity for work, and his arguments, need to be determined and assessed. We developed a questionnaire to elicit the adherence SIPs have to the protocols, their underlying principles and topics. We conducted a survey among one hundred fifty-five experienced SIPs in the Netherlands.</p> <p>Results</p> <p>Ninety-eight SIPs responded (64%). All respondents used some form of protocol, either one of the published protocols or their own mix. We found no significant relation between training and the use of a particular protocol. Ninety percent use a semi-structured interview. Ninety-five percent recognise having to verify what the claimant says and eighty-three percent feel the need to establish a good relation (p = 0.019). Twelve topics are basically always addressed by over eighty percent of the respondents. The claimant's opinion of being fit for his own work or other work, and his claim of incapacity and his health arguments for that claim, reach a hundred percent. Description of claimants' previous work reaches ninety-nine percent.</p> <p>Conclusion</p> <p>Our study shows professional consensus among experienced Dutch SIPs about the principle of assessment on arguments, the principle of conducting a semi-structured interview and the most crucial interview topics. This consensus can be used to further develop a protocol for interviewing in the assessment of incapacity for work in social insurance. Such a protocol can improve the quality of the assessments in terms of transparency and reproducibility, as well as by enabling clients to better prepare themselves for the assessments.</p

Safe administration of etoposide phosphate after hypersensitivity reaction to intravenous etoposide

Etoposide is commonly used in a variety of malignancies. A well known but rare toxicity are hypersensitivity reactions, usually manifested by chest discomfort, dyspnoea, bronchospasm and hypotension. We report the details of a patient who developed hypersensitivity reactions to intravenous etoposide, but subsequently tolerated the administration of intravenous etoposide phosphate with no sequalae