Making cities mental health friendly for adolescents and young adults.

Urban life shapes the mental health of city dwellers, and although cities provide access to health, education and economic gain, urban environments are often detrimental to mental health. Increasing urbanization over the next three decades will be accompanied by a growing population of children and adolescents living in cities. Shaping the aspects of urban life that influence youth mental health could have an enormous impact on adolescent well-being and adult trajectories.

Agents of Change for Mental Health: A Survey of Young People's Aspirations for Participation Across Five Low- and Middle-Income Countries.

Purpose: Effective intervention, policy, and research in mental health and well-being (MHWB) require young people to be understood not only as beneficiaries, but also as active agents in codesigning and implementing initiatives. To identify pathways for young people's participation in promoting MHWB in low- and middle-income countries (LMICs), this study surveyed young people's aspirations for engagement, their spheres of influence, capacity building needs, and key barriers to participation.

Methods: Using U-Report, United Nations Children's Emergency Fund's social messaging tool and data collection platform, we distributed a short quantitative survey to a nonrepresentative, but large sample of young people aged 15-29 across five LMICs: Nigeria, Brazil, Jamaica, South Africa, and Burundi.

Global priorities for climate change and mental health research.

Background: Compared with other health areas, the mental health impacts of climate change have received less research attention. The literature on climate change and mental health is growing rapidly but is characterised by several limitations and research gaps. In a field where the need for designing evidence-based adaptation strategies is urgent, and research gaps are vast, implementing a broad, all-encompassing research agenda will require some strategic focus.

Design of apparatus for precise x-ray dose chamber calibrations.

An apparatus for precision calibration of ion chambers in the x-ray region from 16 to 320 kV is described. The development of a fast-acting shutter with "opening" and "closing" times of less than 3-ms eliminates the requirement for operating time corrections. Controls from outside the radiation room permit changing x-ray filters and alternately positioning both test and standard ion chambers in the x-ray beam.

Free radical production by high energy shock waves--comparison with ionizing irradiation.

Fricke chemical dosimetry is used as an indirect measure of the free radical production of ionizing irradiation. We adapted the Fricke ferrous sulfate radiation dosimeter to examine the chemical effects of high energy shock waves. Significant free radical production was documented.

Increased radiation-induced transformation in C3H/10T1/2 cells after transfer of an exogenous c-myc gene.

C3H/10T1/2 cells were infected with a retroviral vector expressing a mouse c-myc oncogene and a drug-selection marker. The resulting cells, morphologically indistinguishable from C3H/10T1/2, displayed a greatly enhanced sensitivity to neoplastic transformation by ionizing radiation or by a chemical carcinogen. Constitutive expression of myc therefore appears to synergize with an initial carcinogenic event, providing a function analogous to a subsequent event that apparently is required for the neoplastic transformation of these cells.

Potentiation of growth factor activity by exogenous c-myc expression.

The c-myc oncogene has been implicated in deregulation of cell growth in neoplastic cells and response to "competence-inducing" growth factors in normal cells. In the latter case, expression of c-myc has been shown to be associated with the transition from the G0 to the G1 phase of the cell cycle induced by platelet-derived growth factor (PDGF). In the work reported here, we have introduced the c-myc coding region, in a retroviral vector, into mouse and rat cells.

Improved "nonisolated-sensor" solid polystyrene calorimeter.

A "nonisolated-sensor" solid polystyrene calorimeter is described which permits absorbed dose measurements with precision of less than 0.3% (standard error of the mean). The accuracy for obtaining absolute absorbed dose was estimated by comparisons with cavity ionization measurements.

Phosphorus activation neutron dosimetry and its application to an 18-MV radiotherapy accelerator.

Neutron fluxes and dose rates in and near the 18-MV x-ray beam of a Therac-20 accelerator were determined with measured activities from the nuclear reactions 31P(n, rho)31Si (fast neutrons) and 31P(n, gamma)32P (thermal neutrons), published cross sections, and neutron energy spectra from Monte Carlo calculations. Measurements were made in the patient plane in air and at a 10-cm depth in a tissue-similar phantom, and in a plane containing the x-ray target. Orthophosphoric acid solution was identified as a suitable and convenient phosphorus dosimeter material.

"Nonisolated-sensor" solid polystyrene absorbed dose measurements.

A "nonisolated-sensor" solid polystyrene calorimeter was constructed to test the role of thermal diffusion in limiting the length of irradiation time during which temperature measurements with nonisolated sensors could be made sufficiently free of drift for determining dose with radiation fields such as gamma rays, x rays, and high-energy electrons. From measured ratios of dose at 5.0 and 0.

Suppression of melanoma cell tyrosinase activity and tumorigenicity after incorporation of bromouracil for one or two cell divisions.

We have studied the kinetics of suppression of tyrosinase activity and tumorigenicity in unsynchronized B16 mouse melanoma cells (clone B559) exposed to 5-bromodeoxyuridine (BrdU, 3 mug/ml) for one or two cell divisions, then cultured in BrdU-free medium (RM) for five or six days. Bromouracil replaced about 23% of thymine residues after 24 hours (1 cell division) and almost 40% after 48 hours (2 cell divisions) in the presence of BrdU. Upon subsequent growth in RM the extent of replacement declined in a manner consistent with dilution by new DNA synthesis, reaching 5-10% substitution by day 7 of these experiments.