Collecting standardized urban health indicator data at an individual level for school-aged children living in urban areas: methods from EURO-URHIS 2.

Background: Measuring health and its determinants in urban populations is essential to effectively develop public health policies maximizing health gain within this context. Adolescents are important in this regard given the origins of leading causes of morbidity and mortality develop pre-adulthood. Comprehensive, accurate and comparable information on adolescent urban health indicators from heterogeneous urban contexts is an important challenge. EURO-URHIS 2 aimed to develop standardized tools and methodologies collecting data from adolescents across heterogenous European urban contexts. Questionnaires were developed including (i) comprehensive assessment of urban health indicators from 7 pre-defined domains, (ii) use of previously validated questions from a literature review and other European surveys, (iii) translation/back-translation into European languages and (iv) piloting. Urban area-specific data collection methodologies were established through literature review, consultation and piloting. School-based surveys of 14-16-year olds (400-800 per urban area) were conducted in 13 European countries (33 urban areas). Participation rates were high (80-100%) for students from schools taking part in the surveys from all urban areas, and data quality was generally good (low rates of missing/spoiled data). Overall, 13 850 questionnaires were collected, coded and entered for EURO-URHIS 2. Dissemination included production of urban area health profiles (allowing benchmarking for a number of important public health indicators in young people) and use of visualization tools as part of the EURO-URHIS 2 project. EURO-URHIS 2 has developed standardized survey tools and methodologies for assessing key measures of health and its determinants in adolescents from heterogenous urban contexts and demonstrated the utility of this data to public health practitioners and policy makers.

Long-term adverse outcomes in survivors of childhood bone sarcoma: the British Childhood Cancer Survivor Study.

BACKGROUND: With improved survival, more bone sarcoma survivors are approaching middle age making it crucial to investigate the late effects of their cancer and its treatment. We investigated the long-term risks of adverse outcomes among 5-year bone sarcoma survivors within the British Childhood Cancer Survivor Study. METHODS: Cause-specific mortality and risk of subsequent primary neoplasms (SPNs) were investigated for 664 bone sarcoma survivors. Use of health services, health and marital status, alcohol and smoking habits, and educational qualifications were investigated for survivors who completed a questionnaire. RESULTS: Survivors were seven times more likely to experience all-cause mortality than expected, and there were substantial differences in risk depending on tumour type. Beyond 25 years follow-up the risk of dying from all-causes was comparable to the general population. This is in contrast to dying before 25 years where the risk was 12.7-fold that expected. Survivors were also four times more likely to develop a SPN than expected, where the excess was restricted to 5-24 years post diagnosis. Increased health-care usage and poor health status were also found. Nonetheless, for some psychosocial outcomes survivors were better off than expected. CONCLUSIONS: Up to 25 years after 5-year survival, bone sarcoma survivors are at substantial risk of death and SPNs, but this is greatly reduced thereafter. As 95% of all excess deaths before 25 years follow-up were due to recurrences and SPNs, increased monitoring of survivors could prevent mortality. Furthermore, bone and breast SPNs should be a particular concern. Since there are variations in the magnitude of excess risk depending on the specific adverse outcome under investigation and whether the survivors were initially diagnosed with osteosarcoma or Ewing sarcoma, risks need to be assessed in relation to these factors. These findings should provide useful evidence for risk stratification and updating clinical follow-up guidelines.

Plasma-surface reactions at a spinning wall.

We report a new method for studying surface reactions and kinetics at moderately high pressures (<10 Torr) in near real time. A cylindrical substrate in a reactor wall is rotated at up to 200,000 rpm, allowing the surface to be periodically exposed to a reactive environment and then analyzed by a triple-differentially pumped mass spectrometer in as little as 150 micros thereafter. We used this method to study oxygen plasma reactions on anodized aluminum. When the substrate is spun with the plasma on, a large increase in O2 signal at m/e = 32 is observed with increasing rotation frequency, due to O atoms that impinge and stick on the surface when it is in the plasma, and then recombine over the approximately 0.7 to 40 ms period probed by changing the rotation frequency. Simulations of O2 signal versus rotation frequency indicate a wide range of recombination rate constants, ascribed to a range of O-binding energies.

Recombination reactions of oxygen atoms on an anodized aluminum plasma reactor wall, studied by a spinning wall method.

We have studied the recombination of O atoms on an anodized Al surface in an oxygen plasma, using a new "spinning wall" technique. With this method, a cylindrical section of the wall of the plasma reactor is rotated and the surface is periodically exposed to an oxygen plasma and then to a differentially pumped mass spectrometer (MS). By varying the substrate rotation frequency (r), we vary the reaction time (t(r)), that is, the time between exposure of the surface to O atoms in the plasma and MS detection of desorbing O(2) (t(r) = 1/2r). As t(r) is increased from 0.7 to 40 ms, the O(2) desorption signal decreases by a factor of 2 for an O-atom flux of 1 x 10(16) cm(-2) s(-1) and by a factor of 6 when the O flux is 1 x 10(17) cm(-2) s(-1). The O(2) signal decay is highly nonexponential, slowing at longer times and reaching zero signal as r --> 0. A model of O-atom recombination is compared with these time-dependent results. The model assumes adsorption occurs at surface sites with a range of binding energies. O can detach from these sites, become mobile, and diffuse along the surface. This leads to desorption of O, reattachment at free adsorption sites, and recombination to form O(2) that promptly desorbs. With several adjustable parameters, the model reproduces the observed shapes of the O(2) desorption decay curves and the lack of detectable desorption of O and predicts a high O-atom recombination coefficient on anodized aluminum.

Performance of an annular resonator with a polarizer in the annular leg.

Experiments were performed on a CO(2) laser with an annular resonator. The objective of these experiments was to control the polarization in an annular laser and to verify computer code predictions. A Mylar pellicle was placed in the annular leg, and its angular orientation with respect to the optical axis was varied. The pellicle had different transmittances for horizontal and vertical polarizations and also had stress-induced birefringence. At small angles of incidence in the pellicle, the birefringence dominated, and the output had a complicated nature. However, at large angles of incidence, the transmittance difference forced the laser into a well-defined mode for which the near field was horizontally polarized at the top and bottom and the two sides and vertically polarized at intermediate locations. The experimental results were in good agreement with the computer code calculations.

Effect of infrared coating nonuniformity on optical systems.

For precision optical systems, the focus and tilt errors caused by coating thickness nonuniformity can be a serious concern. These errors are wavelength dependent and hence cannot be compensated in an IR optical system by aligning and focusing with an auxiliary visible alignment laser. It is shown here that the coating design can be modified so as to make the aberrations caused by coating thickness nonuniformity approximately equal at the IR design wavelength and the wavelength of the auxiliary laser. In that case, focusing and alignment with an auxiliary laser can substantially correct the effect of coating nonuniformity.

Laser beam characteristics using dc-induced second harmonic generation.

Previous measurements of electric field induced second harmonic generation indicated that the confocal parameter for a laser beam as calculated from the second harmonic intensity profile was in disagreement with that calculated from the measured beam diameter. In this paper, we show that this discrepancy is caused by the departure of the beam from the pure TEM(00) mode. We expand a distorted beam in terms of the component modes by using the experimental beamscan and calculate the second harmonic profile using this expansion. This calculational procedure is found to be consistent with experimental observations.