Factors influencing the photofading of commercial anthraquinone dyes in solution

The photofading of two anthraquinone dyes has been studied in aqueous solution using ultraviolet-visible absorption spectroscopy and flash photolysis. The influence of alcohol concentration, pH, atmosphere, photosensitisers and stabilisers have been examined and these lead to some important conclusions on the mechanism of dye fading. Essentially, the results indicate the photoexcited triplet state of the dye undergoes a process of either electron or hydrogen-atom abstraction depending on the nature of the environment. Other factors such as aggregation and singlet oxygen also appear to play an important role in solution photofading. The relevance of these results to photofading in a polymeric phase is discussed.     

The structure and content of programming knowledge: Disentangling training and language effects in theories of skill development

This article reviews the extensive literature emerging from studies concerned with skill acquisition and the development of knowledge representation in programming. In particular, it focuses upon theories of program comprehension that suggest programming knowledge can be described in terms of stereotypical knowledge structures that can in some way capture programming expertise independently of the programming language used and in isolation from a programmer's specific training experience. An attempt is made to demonstrate why existing views are inappropriate. On the one hand, programs are represented in terms of a variety of formal notations ranging from the quasi‐mathematical to the near textual. It is argued that different languages may lead to different forms of knowledge representation, perhaps emphasizing certain structures at the expense of others or facilitating particular strategies. On the other hand, programmers are typically taught problem‐solving techniques that suggest a strict approach to problem decomposition. Hence, it seems likely that another factor that may mediate the development of knowledge representation, and that has not received significant attention elsewhere, is related to the training experience that programmers typically encounter. In this article, recent empirical studies that have addressed these issues are reviewed, and the implications of these studies for theories of skill acquisition and for knowledge representation are discussed. In conclusion, a more extensive account of knowledge representation in programming is presented that emphasizes training effects and the role played by specific language features in the development of knowledge representation within the programming domain.     

Development and field demonstration of a hardware-compressive fiber-optic true-time-delay steering system for phased-array antennas

We describe the design, fabrication, testing, and antenna-range demonstration of a photonic wavelengthmultiplexed true-time-delay steering system for use with broadband phased-array antennas. The prototype system is based on a unique hardware-compressive architecture and can drive 16 antenna elements over the 0.35-2.1-GHz band with 6-bit angular resolution over a ±45° scan angle.     

Interpretation time of serial chest CT examinations with stacked-metaphor workstation versus film alternator

PURPOSE: Interpretation time of serial staging chest CT cases, which each contained current and previous examinations, with a simple prototype workstation called filmstack was experimentally compared with interpretation time with a film alternator. MATERIALS AND METHODS: The filmstack displayed a "stack" of sections for each examination; user controls allowed rapid selection of preset attenuation windows and both synchronized and unsynchronized scrolling. Eight radiologists were timed as they used the filmstack and the film alternator to interpret four ergonomically complex serial CT cases. RESULTS: All reports dictated on the basis of findings with filmstack and film were of acceptable clinical accuracy. The time to examine a case with filmstack was significantly faster than the time with film, including the time to load and unload the alternator (99% confidence [P = .01]). There was no statistically significant difference in interpretation time between filmstack and prehung film. CONCLUSION: Use of a low-cost stacked CT workstation with a single 1,024 x 1,024 monitor is an effective means of interpreting cases that require comparison of multiple CT examinations.     

Anaplastic large cell lymphoma Hodgkin's-like: a randomized trial of ABVD versus MACOP-B with and without radiation therapy

During the last few years, morphological, immunohistochemical, and genetic findings have placed anaplastic large cell lymphoma (ALCL) as a distinct clinicopathologic entity, and several reports have focused on the existence of different subtypes of the tumor. Particular attention has been paid to the ALCL-Hodgkin's-like (HL) subtype, which seems to be on the border between Hodgkin's disease (HD) and high-grade non-Hodgkin's lymphoma (HG-NHL). From September 1994 to July 1997, during the course of an Italian multicentric trial, 40 ALCL-HLs were randomized to receive as front-line chemotherapy MACOP-B (methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin-a third-generation HG-NHL regimen) or ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine-a scheme specific for HD). All patients with bulky disease in the mediastinum at diagnosis underwent local radiotherapy after the chemotherapeutic program. Complete response (CR) was achieved in 17 of the 19 (90%) patients who were treated with MACOP-B, and in 19 of the 21 (91%) patients who were administered ABVD. The probability of relapse-free survival, projected at 32 months, was 94% for the MACOP-B subset and 91% for the ABVD subset. The majority of patients with mediastinal bulky disease obtained CR (evaluated with 67Ga single photon emission computed tomography [SPECT]) after their radiotherapy. The present study suggests that ALCL-HL, in line with its borderline status, responds in an equivalent way to third-generation chemotherapy for HG-NHL and to conventional HD treatment in terms of both CR and relapse-free survival rates. However, as to the latter, a longer follow-up period may be needed before stating the absolute equivalence of the two regimens used.     

Urinary stress incontinence. Comparison of the Raz technique and the Bologna technique. Analysis of a series of 188 patients

OBJECTIVE: Our purpose was to evaluate and compare the perioperative morbidity and the long-term results of the Raz colposuspension and the Bologna operation for the treatment of stress urinary incontinence in women. STUDY DESIGN: Data of 188 women who underwent either a Bologna operation (group 1) or a Raz colposuspension (group 2) for the treatment of stress urinary incontinence between January 1, 1987 and December 1, 1995 were analysed retrospectively regarding history, preoperative evaluation, associated surgical procedures, complications and cure and failure rate. POPULATION AND METHODS: 80 patients were treated with the Bologna operation and 108 with the Raz colposuspension. Patients with prior anti-incontinence surgery, and patients with a preoperative diagnosis of urge incontinence were excluded from the study. Success was defined both subjectively (complete absence of complaint of stress urinary incontinence) and objectively (no evidence of loss of urine on cough provocation during physical examination). Survival curves were generated in each group for time to event data: "time to recurrent stress incontinence" and compared by the logrank test. A multivariate analysis using a Cox proportional hazards regression model was performed to indentify possible outcome predictors. RESULTS: The success rate of group 1 was significantly higher than that of group 2 (p = 0.00001). The median of success was 51 months in group 1 and 21 months in group 2 (p = 0.00001). The incidence of intraoperative complications in each group (inadvertent cystostomy, hemorrhage) did not differ. The multivariate analyses using the Cox regression model showed that the most highly correlated variable with the surgical cure rate was the type of surgical anti-incontinence procedure adopted: Bologna or Raz (p = 0.00001) CONCLUSION: In our hands, the Bologna operation has a higher cure rate than the Raz colposuspension. For us, when treating patients with stress urinary incontinence by the vaginal route, the Bologna operation is indicated when sufficient anterior vaginal tissue is available to create vaginal bands.     

The Cartwright Report ten years on: the obligations and rights of health consumers and providers

It is ten years since the Cartwright report was published, three years since the code of health and disability services consumers' rights was promulgated and two years since the code came into force which makes it due for review next year. This paper reviews the issues identified by Cartwright and the effect that her investigation into the "Unfortunate Experiment" has had on the provision of health services. Issues of clinical freedom, peer supervision and informed consent are discussed in relation to the Health and Disability Commissioner Act, the Privacy Act and concepts of partnership in health care. Some comments on the present state of the relationships between consumers and providers in the health system are included.     

Carbohydrate chromatography: towards yoctomole sensitivity

Ward atmosphere was assessed with the help of the Ward Atmosphere Scale (WAS) by patients, nurses and physicians on 8 admission units before and after the introduction of the partial open door system. On average, on 45% of the days on which the units could have been potentially open, they were indeed at least temporarily open. Several significant changes in the WAS scores, mostly in desirable direction, were registered. However, close relationship with the partial opening of the units could be substantiated only with regard to the scale "praxis orientation"; still a positive result. No unequivocal relationships could be demonstrated between the introduction of the partial open door system and the changes in the frequency of "special events".